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991.
LIU Na CHEN Hongxia CHEN Xianyao PAN Zengdi TAO Yi 《科学通报(英文版)》2005,50(19):2249-2253
The tropospheric teleconnection pattern between the Indian Ocean Dipole (IOD) and the Pacific Ocean was studied using GISST and NECP/NCAR reanalysis data. Results show that a structure of Rossby wave train extends from the tropical Indian Ocean over southern subtropical regions of Australia and Pacific Ocean to the tropical Pacific Ocean, where a strong correlation between IOD and geopotential height (GH) anomaly of Pacific Ocean exists. Energy propagating pathways of the planetary wave with wave numbers 1-3 are qualitatively in agreement with the Rossby wave train, which implies that the energy propagation of the stationary planetary wave could be responsible for the tropospheric teleconnection between IOD and tropical Pacific Ocean. 相似文献
992.
Precambrian phosphatized embryos and larvae from the Doushantuo Formation and their affinities, Guizhou (SW China) 总被引:1,自引:1,他引:0
CHEN Junyuan CHI Huimei 《科学通报(英文版)》2005,50(19):2193-2200
Weng'an phosphates of the Precambrian Doushantuo Formation, Guizhou (southwestern China) preserve a large number of exquisite biological structures, which are mostly micro-spherical and represent seaweeds, acritarchs and developing eggs related to various groups of metazoans. Here is a report of a variety of developing eggs and larvae, which are most probably of Cnidarian affinity. The eggs examined in the study are composed of early cleavage embryos and two-layered gastrulae. The early cleavage embryos are radial and total cleavage with equal-size blastomeres. The gastrulae mostly bear a large archenteron, which is filled with yolk-degrading organic matter. Ovoid to fusiform planula-like larvae identified in thin sections under light microscope are mostly mouthless and their gastrovascular cavity is filled with possible yolk-degrading organic matter. They are likely representatives of non-feeding larva. The uncommon planula-like structures are hollow, with each having a mouth-like structure on its narrow end. We interpret them as feeding larva. Study of these embryos with possible Cnidarian affinities shed new insight on the origin of metazoans. 相似文献
993.
WU Yu XU Boqing 《科学通报(英文版)》2005,50(19):2153-2156
A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is presented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followed by 2) calcination of the titanate nanosheets at elevated temperatures. The hydrogen titanate nanosheets were prepared first by autoclaving anatase TiO2 powders, obtained by air cal- cining an ethanol-gel of Ti(OH)4 at 500℃, in aqueous NaOH (10 mol/L) at 150-200℃, and then by washing with hydro- chloric acid under supersonic irradiation. While sizes of the nanosheets were found to increase with increasing the temperature of the hydrothermal treatment, the calcination at 400-500℃ of the hydrogen titanate nanosheets that were synthesized at higher autoclaving temperatures (180-200℃) produced monoclinic TiO2 nanosheets with a uniform morphology. By contrast, the same calcination of the titanate nanosheets synthesized at the autoclaving temperature 180℃ led to anatase TiO2 nanoparticles. 相似文献
994.
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
995.
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
996.
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
997.
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
998.
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
999.
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
1000.
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