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中文
Table of Content
10 January 2005, Volume 26 Issue 1
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研究快报
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2005, 26(1): 1-7. doi:
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Articles
Thermoluminescence Properties of Electron Trapping Material Zn
4
B
6
O
13
:Dy
3+
LI Juan, HAO Jing-Quan, ZHANG Chun-Xiang, TANG Qiang, ZHANG Yan-Li ZHOU Ru-Xin, WANG Shu-Bin, SU Qiang
2005, 26(1): 1-4.
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The Dy
3+
-doped Zn
4-x
B
6
O
13
:xDy
3+
phosphors were prepared by solid-state reaction in air at high temperature. The thermoluminescence(TL) glow curves and three-dimensional(3D) spectrum after
60
Co gamma ray irradiation were studied at 293 K. The emission bands at about 480 nm and 580 nm were observed in the three dimensional(3D) spectrum, which are attributed to the characteristic emission from f-f transitions of Dy
3+
ions. The distributions of traps produced by the irradiation of gamma ray can be altered greatly by the change of the concentrations of Dy
3+
ion doped in Zn
4
B
6
O
13
. The peak temperatures shift to higher temperature with the increasing of concentration of Dy
3+
ions in the studied range, this can enhance thermal stability of dosimeter. All glow peaks shift towards higher temperatures with the increase of irradiation dose, i.e. the thermal activation energy(E) is increased with the enhancement of irradiation dose in the studied range. The trap depth E of the main peak of Zn 3.86B
6
O
13
:0.16Dy
3+
phosphor is calculated as 0.73 eV, the frequency factor S=2.43×10
9
s
-1
. The TL dose-response curve to
60
Co gamma-radiation for Zn 3.84B
6
O
13
:0.16Dy in the dose range from 1~100 Gy is linear. The experiment results showed that Zn 3.86B
6
O
13
:0.16Dy has potential use as the materials of gamma-ray thermoluminescence dosimeter(TLD) for clinical dosimeter.
Preface
Preparation and Characterization of Helical Carbon Nanofibers
YU Li-Yan, ZHANG Qian, CUI Zuo-Lin
2005, 26(1): 5-8.
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Helical carbon nanofibers with a symmetric growth mode were synthesized by the catalytic decomposition of acetylene using Cu-Ni alloy nanoparticles as the catalyst prepared by hydrogen-arc plasma method. The morphology of the coiled carbon nanofibers was examined by SEM, TEM and IR. We found that there were only two helical fibers symmetrically grown over a single Cu-Ni alloy nanoparticle, which was faceted with a regular shape(quadrangular, oblong, triangular and rhombus). The two coiled fibers have different coiled chirality, but have identical coil diameter, coil length, and fiber diameter. The angles between the two helical fibers grown on a single catalyst nanoparticles were different(60°, 90°, 110° and 160°). The IR analysis revealed that the molecular structure of helical nanofibers contained both unsaturated —CC— and saturated —CH
2
— and —CH
3
— groups. However, rectilinear carbon fibers were synthesized by the catalytic decomposition of acetylene with Cu nanoparticles and Ni nanoparticles as the catalyst prepared by hydrogen-arc plasma method.
Articles
Fluorescence Property of a Series of Hydroxylphenyl Porphyrins
SHI Ying-Yan, ZHENG Wen-Qi, LI Xiang-Qing, YU Lian-Xiang, WANG Xing-Qiao
2005, 26(1): 9-12.
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The spectral properties of five kinds of synthesized porphyrins were. Studied. It was found that the fluorescence intensity enhanced with the increase in number of peripheral hydroxyl group of porphyrin, and that the fluorescence intensities of tetrahydroxyphenyl porphyrin and tetraphenyl porphyrin at 430 nm were very low, which was related to the structure symmetry. The red-shift of the fluorescence spectra in DMF compared to that in CH
2
Cl
2
can be explained on the bases of the effect of solvation. These results indicate that the compounds with different fluorescence properties could be obtained by controlling the number and the position of peripheral substitute groups of porphyrin and using different solvents.
Synthesis in situ of Active Calcium Carbonate Nanoparticles via Simulating Biomineralization
WANG Cheng-Yu, ZHAO Jing-Zhe, LIU Yan-Hua, GUO Yu-Peng Zhao Xu, DENG Yan-Hui, YANG Hua, WANG Zi-Chen
2005, 26(1): 13-15.
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A new method for mimic biomineralization was used to synthesize CaCO
3
. The organized organic substrates, which could associate with Ca
2+
by means of molecular recognition and induce the nucleation and growth of CaCO
3
, were synthesized fristly, and followed by the preparation of the CaCO
3
by carbonation of a solution of Ca(OH)
2
with CO
2
. Well dispersed spindle-like nano-CaCO
3
particles with an average width of 50 nm and a ratio of diameter to length about 1:5 were obtained under the given experimental conditions. The products were characterized by FTIR spectra, TGA analysis and transmission electron microscope(TEM).
Effects of La
3+
on Outward K~+ Channels at Plasma Membrane in Vicia Mesophyll Cells
XUE Shao-Wu, YANG Pin
2005, 26(1): 16-18.
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The effects of La
3+
on outward K
+
channels at plasma membrane in vicia mesophyll cells were studied by using the whole-cell patch-clamp recording mode. It was shown that La
3+
on both sides of plasma membrane blocked outward K
+
currents in a concentration-dependent manner. The dose response was fitted by the Michalis-Menten relationship characterized by an inhibitory constant K i of (76.59±9.28) μmol/L(outside membrane) and (5.80±0.62)×10
-15
mol/L(inside membrane) respectively, suggesting that intra-cellular La
3+
had a stronger inhibitory effect on outward K
+
currents than extra-cellular La
3+
did. Since K
+
remains the dominant osmoticum in mesophyll cells, the inhibition of outward K
+
currents by La
3+
may contribute greatly to preventing the K
+
loss and promoting turgor maintenance. These results implied that rare earth elements might have potential practical values in regulating plant water status and strengthening plant drought endurance.
Synthesis, Structure and Property of a 2D Network of Silver Complex
ZHU Hui-Fang, FAN Jian, SUN Wei-Yin
2005, 26(1): 19-21.
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A new coordination complex, [Ag(IIMB)N
3
], was prepared by self-assembly of asymmetric ligand 1-(1-imidazolyl)-4-(imidazol-1-ylmethyl)benzene(IIMB) with [Ag(NH
3
)
2
]N
3
. The crystal structural analysis indicates that the structure of the complex contains fifty-two-membered macrometallacyclic rings, and the complex crystallizes in monoclinic system, space group of P2
1
/c with a=0.739 8(1) nm, b=1.045 1(1) nm, c=1.812 4(2)nm, β=91.65(1)°, V=1.400 7(3) nm
3
, Z=4, D
c
=1.774 g/cm
3
, F(000)=744, R=0.050 5, wR=0.084 0. It is notable that the azide ion bridges two silver(Ⅰ) atoms in end-on fashion.
Ordered Multilayer Film Electrode Containing Iron Phthalocyanine Based on Covalently Bonding
ZHAO Shuang, LI Xiao-Fang, SUN Chang-Qing
2005, 26(1): 22-26.
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Construction of a highly stable and covalently bonding multilayer film electrode containing iron phthalocyanine was achieved by UV irradiation of ionic self-assembled multilayer films of diazo-resin(DAR) and iron tetrasulfophthalocyanine(FeTsPc). The fabricated processes of the multilayer film electrode were characterized by UV and IR spectra. The modified electrode not only has stable electrochemical behavior but can also catalyze the electroreduction of TCA. Finally, the diffusion coefficient of TCA was also determined by using chronoamperometry.
Differentiation of the Flavonoid C-glycoside Isomers in Scutellaria baicalensis Georgi Using HPLC-ESI-MS/MS
WU Wei, SONG Feng-Rui, LIU Zhi-Qiang, LIU Shu-Ying
2005, 26(1): 27-30.
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HPLC-ESI-MS/MS is becoming one of the most important tools for the on-line identification of natural products in crude plant extracts. In this paper, a combined HPLC-ESI-MS/MS method was developed to character two flavonoid C-glycoside isomers in Scutellaria baicalensis Georgi. Using tandem mass spectrometry, useful fragments of the two flavonoid C-glycoside isomers were obtained. The experimental results demonstrate that cross-ring ions of [M-H-60]
-
, [M-H-90]
-
, [M-H-120]
-
are characteristic ions of flavonoid C-glycoside. By analyzing the differences of the retention time and the relative abundance of ions [M-H-60]
-
, the two isomers can be distinguished conveniently.
High-resolution Hadamard Transform Microscopic Fluorescence Image Analysis(Ⅲ) —— Influence of Systematic Resolution and the Process of Image Recovery on Single Cell Analysis
TANG Hong-Wu, LI Tao, LUO Mei-Na, WU Qiong-Shui, CHEN Guan-Quan
2005, 26(1): 31-34.
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An improved system of Hadamard transform(HT) microscopic fluorescence imaging was presented. Based on the measurements of single-cell samples, the resolving ability of the system and the process of image recovery were discussed respectively. The results show that the system can be used for both single-cell morphological and quantitative analysis. Pixel resolution of the HT images is identical in x and y two-dimension, and reaches to the resolving power of the microscope under the same imaging lens, hence the system's imaging ability is reliable when the two-dimensional HT image of micron-scale single-cell samples should be obtained, and the system can be effectively applied to the single-cell morphological analysis. The quantitative measurement of fluorescence bleaching of pollen cells demonstrates that the process of image recovery for all these samples should be initialized, when the quantitative data of a same series of samples provided by different HT images should be mathematically compared.
Preparation and Evaluation of Polymer-encapsulated Zirconia-based Packing Stationary Phase for HPLC
YANG Jun-Jiao, ZUO Yu-Min
2005, 26(1): 35-38.
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Novel alkyl and aromatic polymer-encapsulated zirconia-based packings for HPLC stationary phase were synthesized by radical polymerization of olefinic hydrocarbon and divinylbenzene with vinyl-modified zirconia in solution. SEM and
13
C CP/MAS NMR were used to determine the physical properties of these stationary phases. Chromatographic characteristics were evaluated, and pH stability was also examined. Its superior performance for the separation of mixtures of polycyclic aromatic hydrocarbon and anilines were demonstrated.
Application of Subspace Comparison Method in Studying the Relationship Between Topological Block Variables and Variable Selection
SHEN Ju-Wen, HU Qian-Nan, LIANG Yi-Zeng
2005, 26(1): 36-42.
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This paper cares about the relationship about the block variables instead of individual topological index so that we can use subspace comparison to study the high dimensional problem. The data are about five series of topological indices of 530 saturated hydrocarbons. By the cosines of the angles between any two block-variables, the linear correlation between different block variables is studied. It is a good model of boiling point of 530 saturated hydrocarbons with variables, which are selected by the subspace comparison. The subspace comparison is a new method to select variable.
Flow Cytometry and Single Cell Fluorescence Detection on a Microfluidic Device
YAO Bo, FENG Xue, LUO Guo-An, WANG Yi-Ming
2005, 26(1): 43-45.
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A microfluidic device was developed for flow cytometry and single cell fluorescence detection. TO-PRO-3 as a vital DNA dye was used to label dead cells and some of apoptosis cells which could be penetrated from their broken membranes and intercalated into DNA chains. Cells were driven by combined effect of hydrodynamic and electric power and passed through the detection point one by one in micro channels. A laser induced fluorescence detection system which employed a 635 nm semiconductor laser was the only measurement of the whole system. This micro flow cytometor system was applied to estimate the damage degree of those HeLa cells having been exposed to ultraviolet radiation for 10, 20 and 40 min, respectively by the number of cells determined and their fluorescence intensity.
Application of Molecule Wire Polymer in the Determination of Cyanide
ZHAI Qiu-Ge, HUANG Hong-Mei, WANG Ke-Min, TAN Wei-Hong HUANG Shan-Sheng, JIN Yan, LI Bang-Rui
2005, 26(1): 46-48.
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A new method, molecule wire polymer, was developed for the determination of cyanide based on the competitive reaction. The fluorescence of the molecule wire polymer is quenched due to ion-association with Pd
2+
and restored when cyanide was added into the system. The linear detection range is 5×10
-6
—2×10
-4
mol/L and the detection limit is 1×10
-7
mol/L for cyanide under optimal conditions. The possible mechanism of the method was investigated by using absorption spectra. This approach provides a potential useful method for anion detection with a high sensitivity and selectivity.
Solid Substrate Room Temperature Phosphorescence of Eosin-5-isothiocynate and Application in Immune Analysis Using CaCl
2
as an Enhancer
WU Ya-Lan, LI Long-Di, LIU Jia-Ming, ZHU Guo-Hui
2005, 26(1): 49-51.
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Room temperature phosphorescence(RTP) signal intensity of eosin-ITC on a polyamide membrane(PM) was very low, but the signal was increased obviously once some inorganic salts were added into the system at λ
ex
/λ
em
=532 nm/685 nm. The enhancement effect of ⅡA element ions(such as Ca
2+
, Sr
2+
and Ba
2+
) on RTP of eosin-ITC is much obvious than that of Pb
2+
and Hg
2+
used constantly as an outer heavy atom perturber in phosphorimetry. Based on that, a new solid substrate room temperature phosphorescence immunoassay(SS-RTP-IA) for the determination of the human IgG was proposed to demonstrate the feasibility using eosin-ITC as phosphorescent marker. It was found that a good linear relationship with the ΔI
P
was obtained when the amount of human IgG in the range from 6.25 to 400 pg/spot(corresponding to the mass concentration: 15.63 ng/mL—1 μg/L, sample volume of 0.4 μL/spot). The regression equation of working curve can be expressed as ΔI
P
=3.06
2+
0.00864x(pg)(n=7, r=0.996), The detection limit calculated as 3S
b
/k is 0.394 pg/spot. The method was applied directly to the determination of IgG in human serum with a satisfying result. These results show that eosin-ITC can be used conveniently as a RTP marker of high sensitivity.
Microfabrication and Performance of Poly(methyl methacrylate) Microfluidic Chip with Multi-channels
ZHOU Xiao-Mian, DAI Zhong-Peng, LUO Yong, LIU Da-Yu WANG Hui, MAO Xiu-Li, LIN Bing-Cheng
2005, 26(1): 52-54.
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The microchip capillary electrophoresis devices were fabricated by using poly(methyl methacrylate)(PMMA) plastic material via an injection-molding process. The molded devices were enclosed by utilizing a mixed organic solvent to another PMMA film. The channel structure was very well defined and the molded channel surfaces were very smooth. The transmissivity was in the range from 91% to 93%(at the wavelength of 400—1 000 nm). In comparison to glass microchannels, the electroosmotic flow(EOF) in native PMMA channels was low. DNA marker separation was demonstrated in these PMMA devices with a high-resolution separation of double-stranded DNA fragments, chip-to-chip and the run-to-run reproducibility was good, and the relative standard deviation(%) values were below 2.2% for run-to-run data and 2.3% for the chip-to-chip comparisons. The PCR amplification products and proteins were analyzed on the PMMA chips. Such devices lead to the production of low-cost, disposable chips suitable for a variety of separation applications, including DNA sizing, DNA sequencing, protein and medical analysis. The detection limits of Rhodamine 6G dye for the unmodified PMMA chip and the modified PMMA chips were 1.0×10
-10
and 6.67×10
-13
mol/L, respectively.
Effects of Electrostatic and Hydrophobic Interaction on the Stability of SARS Coronavirus 3CL Proteinase Dimer
ZHENG Ke-Wen, YU Qing-Sen, JIANG Yong-Jun, MA Guo-Zheng ZHAO Wen-Na, ZEN Min
2005, 26(1): 55-60.
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The crystal structure of the SARS 3CL proteinase was used to study the electrostatic and hydrophobic interactions between two monomers. Solving the Poisson-Boltzmann equation the finite difference method was used to calculate the electrostatic potential. The solvent accessible surface model was supplied for the molecular surface and hydrophobicity. The electrostatic and hydrophobic interactions were explored under the condition of different pH values. The results indicated that the electrostatic interaction energy, electrostatic desolvation free energy and hydrophobic desolvation free energy showed smaller values when pH values are between 5.5 and 8.5, which indicated that, under the condition, the electrostatic and hydrophobic interaction were favorable to the stability of SARS 3CL proteinase dimer. For the dimer was the active form of the SARS 3CL proteinase, the pH condition was good for retaining the activity of the enzyme. The proteinase had the highest activity at around pH= 7.0 for the strongest electrostatic and hydrophobic interaction, which was consistent with the experimental results. pH values had more influence on the electrostatic desolvation free energy than on the hydrophobic desolvation free energy, which implied that the electrostatic interaction was the key factor to the instability of SARS 3CL proteinase dimer under acidic or alkali condition.
Purification and Function Research of Active Peptide from Pig Blood Hydrolyzed by Trypsin
LI Yan-Wei, JIANG-Bo, TONG Xiang-Shan
2005, 26(1): 61-63.
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To purify the enzymolysis product of porcine blood by trypsin hydrolysis via the biological technique such as ultra-filter and chromatography, we obtain the aim product using HPLC to determine the purity of our aim peptide, its molecular weight is about 3 000. In order to identify the existence of our aim peptide, we performed T lymophocyte transformation test and E rosette forming test for the product of the progress. Furthermore, we carried out the experiments of immunology and pharmacology in vivo and in vitro to ensure that our aim peptide can prove the enhancement immunologic activity of organism.
Catalysis of Manganeseporphyrin Supported on Imidazole-modified Silica Gel for Cyclohexane Oxidation with Air
WANG Xu-Tao, CHU Ming-Fu, GUO Can-Cheng
2005, 26(1): 64-67.
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One of the most interesting trends in oxidation of hydrocarbons with metalloporphyrins as the catalysts is oxidation of alkanes in Lyons system with molecular oxygen. Great achievements made in this field showed that supported metalloporphyrins possessed important application prospects. In order to enhance the stability of the catalyst and make it be used repeatedly, simple manganese tetraphenylporphyrin was successfully supported on silica gel modified with 3-chloropropyltrimethoxysilane and imidazole. This macromolecular metalloporphyrin was used as the catalyst for the first time for cyclohexane oxidation to cyclohexanol and cyclohexanone with air in the absence of additives or solvents. The reaction catalyzed by the modified silica gel-supported manganeseporphyrin still gave yield of 7.1% and selectivity above 90% to cyclohexanol and cyclohexanone for the fourth time use. The results also showed that the molar ratio of cyclohexanone to cyclohexanol was enhanced from 1.35 to 1.76 after the supported catalyst was used for the reaction. The stability of the manganeseporphyrin was obviously improved and can be easily recovered for reuse. The effect of the support on the catalytic activity in this catalysis system has been discussed.
Identification of Interacting Molecules by Biomolecular Interaction Analysis Combined with Surface Plasmon Resonance-mass Spectrometry at 10
-15
mol Level
NIE Song, CHEN Ping, LIANG Song-Ping
2005, 26(1): 68-72.
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Biomolecular interaction analysis mass spectrometry(BIA/MS) is a very promising method applied in proteomics for the characterization of protein-protein interactions. BIA/MS is an approach combining the surface plasmon resonance(SPR) technology with mass spectrometry for the real-time analysis and identification of interaction molecules that interact specifically with a known immobilized ligand. In this study, by using the Biacore-X instrument, about 0.1 pmol β
2
-microglobulin was immobilized on sensor chip, the interacting protein in solution was delivered to the biosensor chip surface. Then, a microrecovery method of the principle of “sandwich” structure was used to elute the bonding microglobulin protein from the sensor chip, and the protein identification was then achieved after tryptic digestion by matrix-assisted laser desorption/ionization-time of flight mass fingerprint mapping and data-base search. The strategy was successfully applied to the model protein microglobulin interacting with its antibody, a unambiguous identification was obtained at 10
-15
mol level.
Antimicrobial and Hemolytic Activities of Melittin and Its Analogues and Their Interactions with Phospholipid Membranes
LI Shun-Zi, SUN Xue-Jun, YAN Hu-Sheng, HE Bing-Lin
2005, 26(1): 73-77.
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The secondary structures of melittin and its analogues in Tris buffer, containing 2 mo/L NaCl and 10% hexafluoroisopropanol(HFIP) were determined by CD method. The results showed that melittin and its analogues adopted random coil structures in Tris buffer. The α-helical content of melittin in the buffer containing 2 mol/L NaCl increased markedly, indicating the formation of aggregates, while the analogues did not show a unique conformation. No correlations between the aggregation and antimicrobial or hemolytic activities were found. The α-helical content of melittin and its analogues increased markedly in 10% HFIP, which was widely used to mimic the biomembrane environment in literature, indicating these peptides have an inherent helicity. By comparing the secondary structures and the antimicobial or hemolytic activities, it was found that membranes of bacteria might be a much stronger promoter of α-helical structures than those of erythrocytes and aqueous HFIP, and membranes of erythrocytes has a similar environment with aqueous HFIP.
Magnetic and Biomimetic Catalytic Properties of New Schiff Base Dinuclear Complexes as Model Compounds of Methane Monooxygenase
CHEN Xin-Bin, LIAO Dai-Zheng, SUN Yong-Fen HU Xin-Juan, YANG Yan, ZHU Shen-Jie
2005, 26(1): 78-80.
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This paper reports the biomimetic catalytic properties of new Schiff base mononuclear complexes MH
2
LM = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[ N,N'-ethylene-2,2'-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)] and dinuclear complexes MnML[M=Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)] for studying the monooxygenation of cyclohexane with PhIO and magnetic properties of the dinuclear complexes. The investigation of the magnetic properties(4—300 K) of the dinuclear complexes revealed that their antiferromagnetic spin exchange with J varied from -10.49 to -0.482 cm -1 except MnZnL, and antiferromagnetic spin exchange decreased in the order: Mn(Ⅱ)-Cu(Ⅱ)>Mn(Ⅱ)-Ni(Ⅱ)>Mn(Ⅱ)-Mn(Ⅱ)>Mn(Ⅱ)-Fe(Ⅲ)>Mn(Ⅱ)-Co(Ⅱ)>Mn(Ⅱ)-Cr(Ⅲ). The yield determination of monooxygenation of cyclohexane indicated that the catalytic reactivity of the dinuclear complex was better than that of the corresponding mononuclear complex, so we supposed that there was some cooperative action between the two metals in these dinuclear complexes. It was found that the cooperation lay in the decreasing order: Mn-Fe>Mn-Cr>Mn-Cu>Mn-Mn>Mn-Co>Mn-Ni>Mn-Zn. It seems that this cooperation increased with the increase of the number of unpaired d electrons and the magnetic exchange between the two metals in these dinuclear complexes.
Two New Steroidal Saponins from the Soft Coral Cladiella sp.
ZHANG Guang-Wen, MA Xiang-Quan, YAN Su-Jun, ZENG Long-Mei, SU Jing-Yu
2005, 26(1): 81-83.
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Two new steroidal glycosides and one polyhydroxylated sterol were isolated from the soft coral Cladiella sp. by HPLC fractionation. The animal material was collected from Sanya bay, Hainan province, China. On the basis of spectroscopic analysis and chemical conversion, their chemical structures were elucidated as pregn-5,20-dien-3β-ol-3-O-α-L-fucopyranoside(1), pregn-5,20-dien-3β-ol-3-O-β-D-xylopyranoside(2) and (22E,24R)-ergost-7,22-dien-3β,5α,6β-triol(3). Compounds 1 and 2 are new compounds.
TD-DFT Theortical Studies on Electronic Structures and Spectrum Properties for BPh
2
(mqp)
TAN Ke, TENG Yun-Lei, KAN Yu-He, YANG Shuang-Yang, SHI Li-Li
2005, 26(1): 84-87.
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BPh
2
(mqp) was optimized by using ab initio HF and DFT B3LYP theories, and the characteristics of the frontier molecular orbitals and the distribution of energy levels were analyzed. Time Depended Density Function Theory(TD-DFT) B3LYP was employed to investigate the electronic spectrum properties of BPh
2
(mqp). It is found that the luminescence originates from the π→π
*
electronic transition among the ligand of mqp. Ornament on the ligand of mqp can affect the distribution of the frontier molecular orbitals and tune the bands of luminescence.
Immobilization of Superoxide Dismutase by Layer-by-layer Assembly on Surface of PS Colloid Particles and Their Bioactivity
HE Cheng-Yi, LIANG Zhen-Peng, WANG Chao-Yang, LIU Xin-Xing, TONG Zhen
2005, 26(1): 88-92.
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Novel enzyme multilayer films on the surface of polystyrene(PS) colloid particles was fabricated by layer-by-layer(LbL) self-assembly. Superoxide dismutase(SOD) was adsorbed on the PS particles as either polycation or polyanion switched by adjusting pH alternatingly with the oppositely charged polyelectrolytes. zeta-Potential and TEM results indicated the regular and stepwise growth of the multilayer structure. The amount of the immobilized SOD was estimated from the difference in SOD bioactivity of the supernatant after adsorption and SOD solution before adsorption by using the pyrogallol oxidation method. The immobilization amount of SOD was 12 and 51 IU when adsorbed in pH=8.0 as a polyanion and in pH=4.3 as a polycation, respectively. However, the relative activity of the former was 23.4% while that of the latter was 2.9%, compared to that of free SOD in aqueous solution. Anionic SOD was found to form more regular and smooth layers on the PS particle surface and cationic SOD to aggregate. By adjusting pH of the adsorption solution we can optimize the assembled status and bioactivity of particle-immobilized enzyme.
Luminescent 1,2-Bis(2-pyridinecarboxamido)benzene Zinc(Ⅱ) Complexes
YE Kai-Qi, WU Ying, GUO Jian-Hua, SUN Ying-Hui, WANG Yue
2005, 26(1): 93-96.
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Luminescent complexes Zn(bpb)(1) and Zn 2(bpb)
2
(bpy)(2)(bpb=1,2-bis(2-pyridinecarboxamido)benzne, bpy=4,4'-bipyridine) were synthesized and complex 2 was characterized by single crystal X-ray diffraction. Crystal data for Complex 2: monoclinic, space group P1, a=0.962 51(6) nm, b=1.501 22(9) nm, c=1.642 52(12) nm, α=106.958(2)°, β=105.362(3)°, γ=102.978(2)°, V=2.068 5(2)nm
3
, Z=2, D
c
=1.563 g/cm
3
, F(000)=1000, R
1
=0.036 7, wR
2
=0.089 8. Complex 2 was formed by two molecules of complex 1, which were linked by a bpy ligand through coordination bonds. In the solid of complex 2, there were face-to-face intermolecular π-π stacking interactions resulting in the formation of one-dimensional molecular chains, which oriented along crystallographic b and c axis, respectively. The photo and electro-luminescent properties of complex 1 were characterized. Complex 1 was employed as an emitting material to fabricate electroluminescent device with a high efficiency.
Preparation and Spectral Behavior of N,N-Bis(α-naphthylphenyl)-4,4'-biphenyldiamine Nanotubes
ZHANG Xiu-Juan, GU Ming-Ming, WU Jia-Sheng, ZHOU Jian-HuaWANG Hui, ZHANG Xiao-Hong, WU Shi-Kang
2005, 26(1): 97-101.
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Aligned nanotubes of organic electroluminescent material(NPB) were prepared by a simple melting method with an anodic aluminum oxide(AAO) membrane as the template. The nanotubes arrays obtained were characterized by means of scanning electron microscope(SEM), energy dispersive X-ray(EDX) analyzer, transmission electron microscope(TEM) and fluorescence microscope, respectively. The prepared nanotubes possessed a uniform shape and regular size. Further investigation indicated that the surface modification of the templates played an important role in the process of preparation. It was also worth mentioning that the nanotubes with different sizes exhibited a very interesting size-dependent photo-luminescence(PL) behavior.
Homology Modeling of Three-dimension Structure of Hepatitis B Surface Antigen Fragment and Its Ligand Design
ZHANG Yuan, LI Ze-Sheng, SUN Miao, XIAO Jing-Fa BAI Yu-Bai, LI Tie-Jin, SUN Chia-Chung
2005, 26(1): 102-105.
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By means of the homology modeling and docking methods, a theoretical study on hepatitis B surface antigen(HBsAg) fragment(44_170) was performed. The three-dimension structure of HBsAg fragment(44_170) is built up based on the crystal structures of whey acidic protein(PDB code 1CJH) and ricin glycosidase (PDB code 2AAI). A new ligand is designed based on the structure of acceptor HBsAg(44_170) and the ligand is docking to HBsAg fragment. The result shows that Trp163 and Trp165 in the complex have strong van der Waals contacts with the ligand, and this result is in agreement with the experimental one in refrence reported by Wang et al. The hydrogen bonding interactions between ligand and tryptophan residues as well as proline residue of HBsAg also play an important role in locating effects. The results obtained may be helpful for further studies of the structure-based ligand designing of new compounds.
Size Effect of Zirconia Nanoparticles in Au/ZrO
2
Catalysts for 1,3-Butadiene Hydrogenation
ZHANG Xin, XU Bo-Qing
2005, 26(1): 106-110.
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This work explores the size-effect of zirconia nano particles on the catalysis of Au/ZrO
2
-AN catalyst for 1,3-butadiene hydrogenation. Zirconia nanoparticles with different sizes(6—30 nm) were prepared by pretreatment at different temperatures(673—1 073 K) and 0.7%Au/ZrO
2
-AN-T catalysts by deposition-precipitation method. The samples were characterized with XRD, TEM, XRF and nitrogen adsorption measurements. While the Au particles in all the 0.7%Au/ZrO
2
-AN-T catalysts appeared to show similar sizes(4—5 nm), the catalytic activity order for 1,3-butadiene hydrogenation clearly revealed that smaller zirconia nanoparticles led to 1%Au/ZrO
2
-AN-T catalyst with higher catalytic activities. A 100% selectivity to butenes is achieved and the trans to cis ratio in 2-butenes is 0.5—1 over all the 1%Au/ZrO
2
-AN-T catalysts. The activity improvement by reducing zirconia particle size seems attributable to increased Au-zirconia junctions in the catalyst, as evidenced by the TEM analysis.
Relationships Between Photoluminescence Performance and Photocatalytic Activity of ZnO and TiO
2
Nanoparticles
JING Li-Qiang, XIN Bai-Fu, WANG De-Jun, YUAN Fu-Long FU Hong-Gang, SUN Chia-Chung
2005, 26(1): 111-115.
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In this paper, ZnO, TiO
2
and Zn
2+
doped TiO
2
nanoparticles were prepared by chemical precipitation and sol-gel method, respectively, and characterized by means of XRD and FS spectra. We mainly investigated the relationships between the photoluminescence performance and photocatalytic activity of the as-prepared samples as well as the photoluminescence mechanism. The results show that ZnO and TiO
2
nanoparticles exhibit obvious FS signals by excitation with the light of higher energy than band-gap energy, and the intensity of FS signals decreased with increasing the temperature of thermal treatment. It should be pointed that the FS signal structure of ZnO and TiO
2
samples are similar, which was possibly related to their similar structure of electronic energy band. It could be demonstrated that FS signals are mainly originated from the energy level of exciton and surface states resulting mainly from surface oxygen vacancies and adsorbed oxygen species. Zn
2+
dopant made the FS intensity of TiO
2
nanoparticle increase, due to the increase in the content of surface oxygen vacancies and defects. In addition, during the experiment of photocatalytic oxidation of phenol, the orders of the photocatalytic activity of as-prepared samples were the same as that of the FS intensity, namely, the stronger the FS intensity, the higher the activity. This was the reason that FS spectra mainly resulted from the surface oxygen vacancies during the photoluminescence process, while surface oxygen vacancies were favourable for the photocatalytic oxidation reaction.
DFT Studies on the Pd
n
(n=2
1
3) Clusters
LI Chun-Sen, CAO Ze-Xing, WU Wei, LIN Meng-Hai, ZHANG Qian-Er
2005, 26(1): 116-120.
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In this paper geometry structures of Pd n(n=2-13) clusters are investigated by using density functional theory(DFT). The most stable cluster structures are in a lower symmetry due to the Jahn-Teller distortions. A variety of structures are very close in energy at the same clusters size. The mean polarizability of an atom in palladium clusters displays an oscillation behavior and the value of the odd-numbered cluster is relatively higher than that of even-size one.
Application of Pitzer's Theory to Multicomponent Electrolyte HCl+H
2
SO
4
+ Glucose Aqueous Solutions Containing Organic Compounds
YANG Jia-Zhen, CHANG Xiao-Hong, XU Wei-Guo, LV Xing-Mei
2005, 26(1): 121-124.
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The standard second ionization constant of sulfuric acid, K
2
, in 15% glucose+85% H
2
O at 298.15 K was determined from the elecromotive force values of cell Pt, H
2
(101.325 kPa)|HCl(m 1), H
2
SO
4
(m
2
), Glucose(x), H
2
O(1-x)|AgCl-Ag The medium effect defined by Owen can be indicated as Pitzer's equation including the parameters of binary terms and triple terms for neutral-neutral and neutral-ion interactions. The values of Pitzer's parameters can be determined by fitting the experimental data in this work. In addition, the experimental data of HCl activity coefficient in the organic solvent-water mixture were treated successfully by this method. The results obtained show that Pitzer's theory can be used to illustrate the medium effect.
Influence of Carbon Paper on Self-humidifying Performance of PEMFC
WANG Cheng, MAO Zong-Qiang, XU Jing-Ming, XIE Xiao-Feng, YANG Li-Zhai
2005, 26(1): 125-128.
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To study the effect of carbon paper on self-humidifying performance of proton exchange membrane fuel cell(PEMFC), the membrane electrode assemblies(MEAs) were prepared by three types of Toray carbon papers TGP-H-028(0.28 mm), TGP-H-060(0.19 mm) and TGP-H-030(0.11 mm), and single PEM fuel cells were assembled by the TGP-H-028 carbon papers treated with PTFE latex of different mass fractions for the experiment studies of polarization and AC impedance. The results showed that the thick carbon paper of TGP-H-028 had a better self-humidifying performance than other carbon papers, and its peak power density increased 0.05 W/cm
2
comparing with that of thin carbon paper TGP-H-030; moreover, the self-humidifying performance of MEA increased with increasing PTFE mass fractions in the range of 20%—40%, the peak power density could increase about 0.25 W/cm
2
. But the self-humidifying performance of the MEA with TGP-H-028 disposed by 60% PTFE was lower than that disposed by 40% PTFE. Finally, the microstructure, pore distribution, and hydrophobicity of the carbon papers were analyzed by methods of SEM, intrusion Hg measurement and surface tension measurement.
Statistical Characters of A
f
-A
a
D
d
Type Hydrogen Bonding System
WANG Hai-Jun, DIAO Jian-Zhi, HONG Zhong-Yan, BA Xin-Wu
2005, 26(1): 129-133.
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Based on the similarities between hydrogen bonding(HB) and polycondensations, we have investigated some properties of a modeling system of HB solutions by means of the statistical theory of polymeric reactions and theory of reaction dynamics. It is shown that some systems may undergo a sol-gel phase transition process under proper conditions. The gelation condition involving the critical HB degrees is given, on which the effects of compettion between the two types of proton donors are then presented. Moreover, we discussed the size distribution of HB clusters and the related problems.
Synthesis, Characterization of β-Diketoiminato Ni(Ⅱ) Complexes and Its Catalytic Performance in Polymerization of Ethylene
GAO Wei, MU Ying, LI Guang-Hua, LIU Xiao-Ming SU Qing, YAO Wei, FENG Shou-Hua
2005, 26(1): 134-137.
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A series of β-diketoiminato ligands with different phenyl substituents and their Ni(Ⅱ) complexes were synthesized. The ligands and the Ni(Ⅱ) complexes were characterized by elemental analysis, 1H NMR and X-ray crystallography. The reaction of NiCl
2
with lithium salt of the ligand and phenyl substituents in THF gives bis(β-diketoiminato) Ni(Ⅱ) complex 1, while the reactions with lithium salt of the ligand with 2,6-Me
2
C
6
H
3
or 2,6-iPr
2
C
6
H
3
substituents produce dimeric β-diketoiminato Ni(Ⅱ) chloride complexes 2 and 3. When activated by AlR
3
, complexes 2 and 3 exhibit high catalytic activities for ethylene polymerization, and polyethylenes with a high molecular weight were abtained.
Synthesis, Structure and Electrochemical Performance of Titanium-doped Spinel Lithium Manganese Oxides
TONG Qing-Song, LIU Han-Shan, LIN Su-Ying, YANG Yong
2005, 26(1): 138-141.
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A series of titanium|doped lithium manganese oxides spinel samples were synthesized by using titanium-doped electrolytic manganese dioxide sample as the manganese sources. It is shown that the titanium|doped samples possess an excellent electrochemical performance whether for 40-charge-discharge-cycle or for second 40-charge-discharge-cycle with samples which stored in the discharged state for 3 months after 40 charge-discharge cycles. The titanium|doped sample synthesized at 600 ℃ possesses a discharge capacities of 206 mA·h/g in the 1st cycle and that of 144 mA·h/g in the 1st cycle after being stored. X-ray diffraction analysis showed that titanium|doped lithium manganese oxides possesses a cubic structure. The vibrational spectroscopic techniques(i.e. IR, Raman) were employed to investigate why titanium can obviously improve the electrochemical performance of spinel lithium manganese oxides.
Morphology of the Silver Iodobromide T-grain Crystal Surface
CAO Li-Zhi, LIANG Xiao-Cong, JIAO Jia-Jun, ZHUANG Si-Yong
2005, 26(1): 142-145.
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The morphologies of the silver iodobromide T-grain crystal surface, the doped emulsion crystal surface with the dopant K
4
[Ru(CN) 6] and the sulfur plus gold sensitized doped emulsion crystal surface were observed. The effects of the light exposure on above crystal surfaces were also studied with AFM. The results show that while the grain surfaces appear to be flat when observed with a common electron microscope or an atomic force microscope with a low resolution power, many hills were revealed on the crystal surface with a high resolution power. After exposure the in situ observation showed that both the heights and sizes of the hills increased. The dopant might affect the amount of the hills. After sulfur plus gold sensitization, the arrangement of the hills turned more regular.
Synthesis of Ester Substituted Copper Phthalocyanines by Phase Transfer Catalysis Reaction and Their Photoconductivity
WANG Yong, CHEN Hong-Zheng, WANG Mang
2005, 26(1): 146-148.
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Copper-tetra-4-(butyloxycarbonyl) phthalocyanine, copper-tetra-4-(octyloxycarbonyl) phthalocyanine and copper-tetra-4-(dodecoxycarboxyl) phthalocyanine were synthesized by the phase transfer catalysis reaction. The reaction has several advantages in comparison with the previous carboxyl-esterified method, such as the milder conditions, the shorter reaction time(3—6 h), the higher yield(>95%), and so on. Because of the difference in the substituent group length of these compounds, the morphology and the congregation of the molecules in their casting films is different, leading to the different photoconductivities of them.
Addition of Cyclohexanone with Acrylonitrile Catalyzed by (R)-TTCA·K
SHANG Yan-Mei, WANG Hui-Ping, WANG Lei, LI Ye-Zhi, HUANG Hua-Min
2005, 26(1): 149-151.
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It is one of the most attractive types of asymmetric synthesis that chiral commpounts are generated under the influence of chiral catalysts. In recent years catalytic asymmetric Michael addition by chiral metal complexes has been recognized as an efficient method for obtaining asymmetric products. In this work we reported that using potassium thiazolidine -2-thione-4-carboxylate [(R)-TTCA·K] as the chiral catalyst, the addition reaction of cyclohexanone with acrylonitrile was carried out and optically active (S)-(+)-2-cyanoethyl cyclohexanone 1 ([α] 20 D=+2.8°, e.e. 19%) and hydrolysis product of 1, (S)-(-)-2-oxocyclohexanepropionic acid 2 ([α] 20 D=-2.95°, e.e. 19%), were obtained. Enantiomeric excess of compound 1 was determined by resolution of (R,S)-2-oxocyclohexanepropionic acid with (-)-quinine. Compounds 1 and 2 were easily racemized at a long time for laying aside and in the presence of dil H
2
SO
4
or dil base. When (S)-(+)-2-cyanoethyl cyclohexanone reacts with ethylene glycol in the presence of toluene sulfonic acid as the catalyst the racemic 2-ethylendioxy cyclohexyl propionitrile was obtained. The mechanism of the reaction of cyclohexanone with acrylonitrile would be a complicated catalysis process.
Modification of Zeolite Y Impregnated by Preformed MFI Alumino-silicate Precursors and Catalytic Properties in Benzene Alkylation with Isopropanol
LIN Sen, YIN Cheng-Yang, WANG Li-Feng, JIANG Da-Zhen, XIAO Feng-Shou
2005, 26(1): 152-154.
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A novel method for increasing the conversion and optimizing the product distribution over the catalyst of zeolite Y modified by MFI aluminosilicate precursors in the reaction of benzene alkylation with isopropanol is reported. The catalyst(PASP MFI/Y) is prepared from the impregnation of zeolite Y with preformed MFI aluminosilicate nanoclusters. The characterization of temperature-programmed desorption of ammonia shows that the PASP MFI/Y exhibits a stronger acidity than Y zeolite does. The catalytic results show that the PASP MFI/Y exhibits a more excellent activity(conversion for isopropanol and toluene) and shape selectivity(p-and m-cymene) in the reaction than zeolite Y.
Enhancement of the Stability of ZnSe Nanocrystals Doped in Silica by a New Method
KONG Fan-Tao, WANG Min-Qiang, WANG Yun-Peng, YAO Xi, JIANG Hai-Qing
2005, 26(1): 155-157.
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ZnSe nanocrystals doped in silica were prepared by using sol-gel process and in situ growth technique. It was found that when n(Zn):n(Se)=1:1 in the sol precursor, the resultant ZnSe nanocrystals were rather instable and after several days the color of the ZnSe nanocrystals-doped SiO
2
glass changed from yellow to red. According to the analysis results of XRD, UV-Vis transmission spectra and XPS, the existence of many zinc vacancies in the ZnSe nanocrystals was considered as the reason of the instability. Based on this reason, the synthesis process was improved by introducing much larger amount of zinc to the precursor sol and this made the stability of the ZnSe nanocrystals improved greatly from several days to more than 6 months.
Compatibility and Conducting Properties of PANI-DBSA/PAN Blend
JIANG Jian-Ming, PAN Wei, YANG Sheng-Lin, LI Guang
2005, 26(1): 158-161.
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Conducting composites of polyacrylonitrile(PAN) copolymer containing 10% mass fraction methylacrylate and dodecylbenzene sulfonic acid doped polyaniline(PANI-DBSA) were prepared by solution blending of the two components. The electrical properties of the blends were characterized by means of electrical conductivity measurements and the phase structures were investigated via scanning electron microscopy(SEM), X-ray diffraction(XRD), FTIR spectroscopy and different scanning calorimetry(DSC). DSC measurements showed that there was only one T g for each blend and the values of T g varied with the change of the PANI-DBSA content. This implies that the PANI-DBSA/PAN blend is at least partially compatible. The formation of the hydrogen bonding between the carbonyl groups in PAN copolymer and the imines groups in PANI-DBSA was identified by the FTIR spectra. XRD demonstrated that the intrinsic layered arrangement of PANI-DBSA was destroyed in the blends. Nanosize network structure of PANI-DBSA dispersed in PAN matrix and the so-called phase reverse occurring in the skin layer of the film samples at low PANI-DBSA loading were observed by SEM. {
Effect of a Fluoro-coating on Oxygen Transport Performance and Lifetime of a Polymer-cobaltporphyrin Membrane
SHENTU Bao-Qing, WENG Zhi-Xue, PAN Zu-Ren, NISHIDE Hiroyuki
2005, 26(1): 162-165.
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A membrane having a long lifetime was prepared by spin-coating a perfluororesin on the polymer-cobaltporphyrin membrane, while the coating had no significant effect on the oxygen permeability and oxygen/nitrogen selectivity of the membrane. The oxygen-binding properties of CoP and facilitated oxygen transport of the coated membrane were also studied. It was found that CoP fixed even in the coated membrane had rapid and reversible oxygen-binding properties in response to the partial oxygen pressures and the apparent oxygen-binding equilibrium constants of CoP were not influenced by the coating. Oxygen permeation was selectively facilitated with CoP fixed in the perfluororesin-coated membrane, whereas the water vapor permeability was significantly suppressed in comparison with that of the uncoated membrane. With increasing the coating thickness, the oxygen permeability coefficients slightly decreased, but the water vapor permeability coefficients significantly decreased. The lifetime of the CoP as an oxygen-carrier in the perfluororesin-coated membrane was prolonged, which was attributed to the hydrophobic property of the coating.
Synthesis and Characterization of a Novel Kind of Poly(aryl ether ketone) Rigid Macrocycle with a [1,1']-binaphthalenyl Structure and Its Manacle-like Dimmer
DANG Guo-Dong, ZHOU Hong-Wei, YANG Wei, CHEN Chun-HaiWU Zhong-Wen, LI Fei
2005, 26(1): 166-169.
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As a part of the work for the functionalization of aromatic macrocyclic oligomers, a novel kind of aromatic macrocyclic oligomer was designed and synthesized containing a [1,1']-binaphthalenyl structure and a p-chlorophenyl substituent. And then by a simple nickel-catalyzed coupling reaction, two macrocycles were connected with each other by a covalent bonding to get its manacle-like dimmer with two [1,1'] binaphthalenyl moieties. With MALDI-TOF MS analysis, 1H NMR spectrum and H-H COSY analyses, the structures of the macrocycle and its manacle-like dimmer were characterized.
Preparation and Properties of Polymeric Solid-solid Phase Change Materials of Polyethylene Glycol(PEG)/Poly(vinyl alcohol)(PVA) Copolymers by Graft Copolymerization
ZHANG Mei, NA Ying, JIANG Zhen-Hua
2005, 26(1): 170-174.
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New serials of PVA-g-PEG graft copolymers with different molecular weights and different graft ratios were prepared. In these new materials,the rigid polymer PVA served as a skeleton, and the flexible polymer PEG served as a functional branch chain. The structures of the copolymers were measured with FTIR. Their phase change properties and crystallization behavior were analyzed by DSC, POM, and WAXD. During the transition, the whole polymers remained in the solid state, they all had solid-solid phase transition properties, and the phase transitions were all reversible. Compared with pure PEG, the maximum crystalline temperatures and enthalpies of the graft copolymers declined because of the addition of PVA and the value of phase change temperatures and enthalpies had no relationship with their graft ratio. The crystalline degrees of these phase change materials were affected due to the intermolecular interaction and chemical bond.
Preparation of PEGT/PBT Tissue Engineering Scaffolds by Solution Spray Method
LIU Hou-Li, CHEN Jin-Wu, WANG Lian-Cai, WANG Chang-Yong, FENG Zeng-Guo
2005, 26(1): 175-178.
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A novel method for solution spray at a high nitrogen pressure was applied in the preparation of tissue engineering scaffolds. The chloroform solution of biodegradable poly(ether ester) poly(ethylene glycol terephthalate)/poly(butylene terephthalate)(PEGT/PBT) was nebulized to give fibers in the nitrogen current and subsequently to accumulate into non-woven scaffolds. At the same time, the hyaluronic acid(HA) aqueous solution was sprayed onto the surface of the resulted fibers to form more biocompatible scaffolds. The implant experiments indicated that these scaffolds were perfect in biocompatibility. HA used as an extracellular matrix improved the biocompatibility of the non-woven scaffolds.
Preparation and Structural Characterization of Several Oligoguluronic Acids
WANG Ying, YU Guang-Li, ZHAO Xia, GUAN Hua-Shi, DU Yu-Guo
2005, 26(1): 179-183.
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The polyguluronic acid obtained from alginate was degraded through acid hydrolysis. The oligosaccharides mixture was fractionated by LPGPC and HPLC methods, and Fluorophore-Assisted-Carbohydrate-Electrophoresis(FACE) was used to confirm their purity. The structure of these oligosaccharides were determined as diguluronic, triguluronic, tetraguluronic and pentaguluronic acids by IR, ESI/MS/MS and 1D, 2D NMR techniques.
Self-assembled Multilayers Films of Photopolymerizable Amphiphile Used as Nematic Liquid Crystals Photoalignment Layer
PENG Zeng-Hui, YU Tao, RUAN Sheng-Ping, XUAN Li
2005, 26(1): 184-188.
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A cationic bolaform amphiphile which had two double-bonds and could be polymerized by ultraviolet was synthesized. A layer-by-layer self-assembled film was prepared in aqueous solution by using this material and poly(sodium 4-styrenesulfonate). The UV-Vis spectra proved that the multilayers film was uniform. When polarized UV irradiated the film, the photosensitive double bond could be polymerized via [2+2] cycloaddition, and the production of reaction distributed along the polarized direction of incident UV. So that by this method an anisotropic film was prepared, we used this anisotropic film as alignment layer of nematic liquid crystals, and obtained a uniform and stable alignment result.
Surface Modification of Polypropylene Microporous Membrane by the Immobilization of Dextran
YANG Qian, XU Zhi-Kang, Mathias Ulbricht
2005, 26(1): 189-191.
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Aminoethyl methacrylate(AEMA) was grafted onto the polypropylene microporous membrane by photo-induced polymerization to immobilize dextran. XPS spectra confirmed the chemical change of the membrane surface after the graft polymerization of AEMA and the immobilization of dextran. The water contact angle measurement indicated that the hydrophilicity of the membrane surface can be increased reparably by the dextran immobilization.
AFM Observation of Sunflower-like Crystalline Morphology Formed in Ultra-thin Film of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)
WANG Zhen, XU Jun, XIE Xu-Ming, WANG Xiu-Feng
2005, 26(1): 192-194.
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Poly(3-hydroxybutyrate-co-103-hydroxyhexanoate)(PHBHHx) thin films were prepared by means of spin-coating PHBHHx/chloroform solutions on the silicon substrate. The crystalline morphologies of PHBHHx thin films were observed by atomic force microscopy(AFM) at room temperature. A novel crystalline morphology, that is like sunflower was found when the film is very thin and named as sunflower-like crystalline morphology. Compared with usual PHBHHx spherulites, there are obvious differences in aspects of nucleation, crystal growth process and crystalline morphology for the sunflowers. The PHBHHx/chloroform solution properties and the substrate have great effects on the formation of the sunflower. A circular boundary that may result from a liquid-liquid phase separation in PHBHHx solution first formed in the thin film during the spin-coating process, then it induced the formation of the sunflowers.
Direct Formation of Isotactic Poly(1-butene) Form Ⅰ Crystals in Solution-cast Thin Films
LV Kang-Bo, CHEN Ye, YANG De-Cai
2005, 26(1): 195-196.
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The morphology of solution-cast thin films of isotactic poly(1-butene)(iPB-1) was investigated by using transmission electron microscopy(TEM) and electron diffraction techniques. The crystalline morphology of the solution-cast films of iPB-1 is greatly dependent on the preparation temperature. When the temperature is in the range of 90—100 ℃, metastable form Ⅱ spherulities are formed. Stable iPB-1 form Ⅰ crystals are achieved directly when the preparation temperature is higher(105—115 ℃).
Effects of Self-seeding Nucleation on Crystallization Behavior of Syndiotactic 1,2-Polybutadiene
TONG Cui-Yan, XIE De-Min, YANG De-Cai
2005, 26(1): 197-198.
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We have reported the synthesis, morphological structure and single crystal structure of crystalline syndiotactic 1,2-polybutadiene. Now we want to study the effect of self-seeding nucleation on the crystallization behavior of it. In the report, the effects of self-seeding nucleation the crystallization behavior of syndiotactic 1,2-polybutadiene were studied by DSC and PLM techniques. The results indicated that the crystallization temperature of crystalline syndiotactic 1,2-polybutadiene increased obviously and the spherulite size decreased markedly after the process of self-seeding nucleation treatment.
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