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991.
Study on synthesis of polylactide from kitchen garbage 总被引:6,自引:0,他引:6
WANG Qunhui SUN Xiaohong Ma Rui & ZHAO Wenchao . Department of Environmental Science Engineering Harbin Insti-tute of Technology Harbin China . Department of Environmental Engineering University of Science Technology Beijing Beijing China 《科学通报(英文版)》2005,50(13):1315-1319
Polylactide, a kind of synthetical aliphatic polyesters, has excellent biologic compatibility and biodegradable properties. It can be degraded in the human body by sim-ple hydrolysis of the ester backbone to non-harmful and non-toxic compounds, and finally be biodegraded into CO2 and H2O in the environment. Therefore, for many years, the polylactide is widely used as drug delivery sys-tems, resorbable suture materials and implantable medical devices. Besides medical applications, it will be … 相似文献
992.
REN Zhibin JIANG Huilin LIU Guojun & SUN Qiang . State Key Laboratory on High Power Semiconductor Lasers Chang-chun University of Science Technology Changchun China . State Key Laboratory of Applied Optics Changchun Institute of Op-tics Fine Mechanics Physics Chinese Academy of Sciences Changchun China 《科学通报(英文版)》2005,50(13):1309-1314
Subwavelength surface-relief gratings whose periods are smaller than incident wavelength have antireflective characteristics[1―4]. People could etch the surface of an optical element or a substrate to fabricate subwavelength surface relief grating to acquire low reflectivity; therefore, the grating could take the place of conventional optical thin films. Because the material of the surface relief grat-ing is the same as its substrate, the stability of the grating is better than that of the co… 相似文献
993.
LIYong WEILuoxia NIUYi YINJunxun 《科学通报(英文版)》2005,50(13):1304-1308
Monkey language models are defined for Chinese Phrase Networks, and scale-free features of Chinese Phrase Networks are uncovered. It is pointed out that the ratio of average degree to the total number of nodes (K/N) is close to a constant. Simulation for the evolution of phrase networks indicates that one of the important reasons for power law distributions is the word selection frequency,which, when tuned aptly, can make the monkey language present similar statistic traits as that of natural languages.Power law tails emerge at large k, and the exponent is about 6. Comparison between monkey model and natural language shows that humans are able to use Chinese words resourcesin more effective and compact ways to express their intentions. All the results demonstrate an important fact that the least effort principle is the basis of Chinese Phrase Networks. 相似文献
994.
ZHANGXiao SHIMAZAKIKen-ichiro 《科学通报(英文版)》2005,50(11):1166-1168
Phototropins, following the discovery of phytochromes and cryptochromes, are the most recently characterized blue-light (BL) receptors in plants. The Nterminal regions of the proteins contain two light oxygen and voltage (LOV)--LOV1 and LOV2, which belong to PAS domain involved in protein-protein interaction and ligand binding, 相似文献
995.
YUShan WANGXiusong FUYu ZHANGJie MAYuanye ZHOUYifeng 《科学通报(英文版)》2005,50(11):1163-1165
Visual function declines during normal aging. The neural mechanisms underlying age-related changes have just begun to be revealed. It has been demonstrated that retinal ganglion cells and cells in dorsal lateral geniculate nucleus (dLGN) in old monkeys are relatively normal. However, age-related functional degradations have been found at cellular level in mammalian visual cortex. 相似文献
996.
LI Qiuli HEN Fukun WANG Xiuli LI Xianghui LI Chaofeng 《科学通报(英文版)》2005,50(24):2861-2865
Both low procedural blank and high-precision measurements of isotopic ratios are crucial for the analysis of micro samples. This study reports a chemical procedure of ultra-low blank for the high precision measurement of Sr isotopic ratios on micro samples (〈1 ng level) using a new-type thermal ionization mass spectrometer IsoProbe-T, with a case study of single-grain Rb-Sr isochron dating on phlogopite from the Fuxian kimberlite in Liaoning Province. This method can be employed in studies of high resolution Rb-Sr geochronology and Sr isotopic geochemistry and thus will broaden application of the Rb-Sr isotopic system to earth sciences. 相似文献
997.
ZHANG Yong WANG Mei YAO Yingming SHEN Qi 《科学通报(英文版)》2005,50(24):2817-2820
An unexpected carbon-oxygen bond cleavage of THF (THF = tetrahydrofuran) promoted by guanidinate titanium complex was described. Guanidinate lithium [Pr2 ^1NC(NCy)2]Li (Cy = cyclohexyl) formed in situ reacted with TiCl4(THF)2 in a 2:1 molar ratio to produce the guanidinate titanium chloride [Pr2 ^1NC(NCy)2]2TiCl2 (1) in good yield. The reaction of [Pr2 ^1NC(NCy)2]2TiCl2 with lithium diisopropylamide in THF afforded an unexpected [Pr2 ^1NC(NCy)2]2Ti(OBu^n)2 (2), which was formed by the cleavage of carbon-oxygen bond of THF. Complexes 1 and 2 were fully characterized by elemental analysis, NMR and IR spectroscopies, and X-ray crystal structure determination for complex 2. 相似文献
998.
HUMaobin WUQingsong KONGXiangzhao WUYonghong 《科学通报(英文版)》2005,50(11):1076-1078
A new siyle of discharge proteins from a vertical open-top pipe with eapillary outlet is reported. The outflux fluctaales greatly with time and the hulk condensed granular flow in Ihe pipe shows stop-and-go motion when the filling height is ahove a threshold. When the filling height falls towards the threshold, led by a transitional stage, the outflux and the bulk movement become much stable. The upper surface dropping velocity variatiun is measured. A heuristic theory is proposed to understand the stop-and-go mntion and the transitional behavior. 相似文献
999.
WANGHaiyan WANGXiaodong ZHAOJingsong SUNCheng WANGLiansheng 《科学通报(英文版)》2005,50(10):961-964
A new molecular representation, molecula rhologram, is employed to investigate the quantitative relationships between gas chromatographic retention indices (GC-RI) and molecular structures of polychlorinated dibenzofurans (PCDFs). Together with application of partial least squares (PLS) regression, the quantitative structure-retention relationship (QSRR) model is constructed for GC-RI of 135 PCDFs. This new QSRR model presents high statistical quality and predictive value with crossvalidation correlation coefficient q2Loo values of 0.998, and non-crossvalidationcorrelation coefficient r2 of 0.998. 100 PCDFs are selected randomly as training set and the rest as testing set. The resuit of PLS regressive analysis of training set yields r^2 of 0.998 and q2Loo of 0.997. The GC-RIs of testing set are predicted, and the correlation equation indicates that the model based on training set has excellent ability to predict the GC-RIs of PCDFs in testing set. 相似文献
1000.
“Insiders” and “outsiders” to social issues is a concept that is an integral part of Participatory Action Research, which emphasizes the partnering and working together with people who are closest to the problem by dint of personal experience and identity, in order to address complex social problems. The writer believes that working with “insiders” in regard to social issues is a powerful concept but not as simple as it might at first seem to be. This paper explores the problems associated with accepting the concept wholeheartedly by using a real-life example of a community issue to explore it. 相似文献