检索结果-南通市图书馆

Study on genetic diversity of cultivated populations in 4 species of shrimps

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2003年第1期22卷 97-102页

作者： LiZhongbao WuZhongqing SchoolofOcean-environment XiamenUniversityXiamen361005China FisheriesCollege JimeiUniversityXiamen361021China

Genetic diversity of cultivated populations was investigated using assay of vertical slabpolyacrylamide gel electrophoresis in 4 species of shrimps, which were Penaeus japonicus, Penaeus monodon , Penaeus vannamei and Metapenaeus ensis, The results showed that the mean number of alle-les per locus (A) is 1.3±0.2. 1.3±0.1, 1.3±0.1 and 1.3 ±0.1 respectively; the percentage of polymorphic loci (P0.95) is 12.5, 6.7, 2. and 2..5 respectively; the expected heterozygosity (He) is 0.042.0.034,0.042.0.031, 0.094±0.042.and 0.097±0.047 respectively; and the observed heterozygosity (H0)is 0.02.±0.02., 0.02.±0.02.,0.154±0.082.and 0.150±0.084 respectively. The difference of genetic diversity is obvious in 4 species of shrimps. The degree of genetic diversity is M. ensis > P. vannamei > P. japonicus > P. monodon. In short, the lower level of genetic diversity is estimated in 4 species of shrimps.

关键词： Penaeus vannamei Penaeus japonicus Penaeus monodon Metapenaeus ensis allozyme genetic diversity

Preliminary study on nanodiatom in the Taiwan Strait

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2000年第1期19卷 91-98页

作者： Guo Jian Huang Bangqin Cheng Zhaodi Hong Huasheng (1. department of Biology, xiamen university,{2., china. 2. Research Lab of SEDC on Marine Ecological Environment, Environmental Science Research Center, xiamen university,{2., china. department of Biology Xiamen University Xiamen 361005 China Res. Lab. SEDC Mar. Ecol. Environ. Environ. Science Research Center Xiamen University Xiamen 361005 China

The preliminary study on nanodiatom in the Taiwan Strait was carried out using transmission electron microscopy (TEM) in February 1995. Thirty-three species of nanodiatom (2. μm) were identified, among which, 6 were new recorders in china. The dominant species were Minidiscus comicus Takano and Thalassiosira tenera Proschdinae -- Lavrenko in the northern Taiwan Strait (NTS), Minidiscus trioculatus (F. J. R. ) Hasle and Natvicula climacospheniae both in the southern Taiwan Strait (STS). Abundance of nanodiatom was much more than that of microdiatom (>2. μm), and the abundance of nanodiatom in NTS is higher than that in STS. The highest abundance of nanodiatom was at the depth of 10 m of N33o in NTS, while at the depth of 2. m of S105 in STS. The vertical distribution of nano- and micro-diatom of NCI showed that the peak was at the depth of 30 m.

关键词： Nanediatom Taiwan Strait abundance species diversity

Swift/BAT Observations of X-Ray Flashes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2008年第3期8卷 309-313页

作者： Yi-Qing Lin department of mathematics and Physics Xiamen University of Technology Xiamen 361024 China

An analysis of prompt gamma-rays of X-ray flashes （XRFs） observed with the Swift/BAT has been presented. Our sample includes 2.5 bursts. It is found that the BAT detection ratio of XRFs to typical Gamma-ray bursts （GRBs） is 42.193, for division at Г= 2.（roughly corresponding Ep ～ 50 keV）, Г being the power law index of the BAT spectrum and Ep, the peak energy （Ep） of the vfv, spectrum. This is consistent with the HETE-2.observations. For both XRFs and GRBs F are almost normally distributed in the range of 1 to 2.8, similar that observed with HETE-2. The distribution of F for the entire set of GRBs/XRFs is not available due to poor statistics on the peak at Г 〉 2.3. This result probably indicates that the BAT spectrum of a typical XRF could have a Г of roughly 2.3, if they indeed are a distinct soft component of the GRB population. By comparing the fluence and the peak flux in different energy bands, it is found that the XRFs are ordinarily softer than the GRBs, but during the peak time the spectra of both GRBs and XRF are similar, showing that the dominant radiation mechanisms of both GRBs and XRFs are similar.

关键词： gamma-rays bursts

Development rate of Labidocera euchaeta Giesbrecht in xiamen Harbor

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1990年第3期9卷 439-447页

作者： Lin Senjie and Li Song department of Oceanography, xiamen university, {2., china

-The development rate of Labidocera euchaeta Giesbrecht in the xiamen Harbor was studied in laboratory. The results showed that the development times of egg and larval stages ( D ) were significantly correlated with temperature ( T ), following the Belehradek function, D = α( T -7. 5)-1.0634. The development time from egg to larval stages and adult, as well as generation time can be predicted from the equation for egg development ( α=411/2.) by appropriately multipling the constant (α) with a proportion. The development was not isochronal over the whole larval period. Durations of naupliar stages were short and quasi-isochronal, which favored their non-feeding development. In contrast, durations of copepodid stages (C) were long. CV had the longest duration followed by CI, both of which are considered as the critical stages in the larval development. The acclimation effect of the seasonal temperature on the development rate was also observed.

关键词： Th Lab Development rate of Labidocera euchaeta Giesbrecht in xiamen Harbor rate

α-AMIDOALKYLATION　VIA　SULFONES:TOWARDS　THE　SYNTHESIS　OF　ANT　VENOM　ALKALOIDS

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1995年第9期6卷 739-742页

作者： Pei Qiang HUANG Xiang Su FEI and Hong ZHENG(department of Chemistry, xiamen university,{2.) xiamen Univ Dept Chem Xiamen 361005 Peoples R China

Abstract: We described the synthesis of two 5-substituted γ-lactams Ⅰand Ⅱ by sulfone-baaed α-amidoalkylation method. This constitiutes the formal synthesis of ant venom alkaloids 2.and 3 in racemic form. The key ... 详细信息

关键词： ANT OF VENOM AMIDOALKYLATION SULFONES SYNTHESIS VIA ALKALOIDS

Square ZnO nano-column and its thermal evolution

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第2期53卷 309-312页

作者： HUANG BinWang, ZHAN HuaHan, WU YaPing, CHEN XiaoHang & KANG JunYong Key Laboratory of Semiconductor Materials and Applications, department of Physics, xiamen university,{2., china 1. Key Laboratory of Semiconductor Materials and Applications Department of Physics Xiamen University Xiamen 361005 China

Square ZnO nano-columns have been manufactured by molecular beam epitaxy on p-type Si (100) substrate. The morphology and the evolution sequences after thermal annealing were investigated by in-situ scanning tunneling microscopy. We associated the morphology and microstructure evolution with the cubic Si (100) substrate, large lattice mismatching, the coexistence of wurtzite and zincblende phases of ZnO, and the thermal effect.

关键词： ZnO square nano-column anneal wurtzite phase zincblende phase Si (100)

Ab Initio Calculations of the Electronic Structures of Copper Pyrites CuS2. CuSe2.and CuTe2

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2004年第4期20卷 429-431页

作者： Zhufeng HOU, Aiyu LI, Zizhong ZHU and Meichun HUANGdepartment of Physics, xiamen university, Fujian {2., china Dept. of Phys. Xiamen Univ. Xiamen 361005 China

The electronic structures of CuS2. CuSe2.and CuTe2.with pyrite structures, within the framework the density-functional theory have been investigated. The calculated results explained the recent experimental results which show that there is no clear indication of strong electron correlations in the electronic properties of Cu pyrites, due to the dominant chalcogen p character rather than d characteristic of Cu at the Fermi level.

关键词： Ab initio calculations Copper pyrites Electronic structures

Distribution of dissolved organic carbon in and near the Prydz Bay, Antarctica

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2003年第4期22卷 547-556页

作者： Qiu Yusheng1, Chen Min1, Huang Yipu1, Liu Guangshan1 1. department of Oceanography, xiamen university,{2., china. xiamen Univ Dept Oceanog Xiamen 361005 Peoples R China

During the 16th Chinese National Antarctic Research Expedition (chinaRE) (from November 1999 to April 2.00) seawater samples were collected for (DOC) determination in the Prydz Bay and its nearby sea areas. DOC concentrations were determined-by high temperature catalytic oxidation (HTCO) method. The results shows that DOC concentrations, in the upper water column (0 similar to 100 in) range from 14.3 to 181.1 mumol/dm(3), with averaging 52.5 mumol/dm(3) (n = 55). These values are slightly higher than those reported for the Ross Sea, the Pacific Ocean and others. Profiles of DOC concentration in the study areas show a decreasing concentration with increasing depth in the upper 100 m, which is related to biological activities in the water column. DOC concentrations below 100 in are relatively constant with a mean of 40.4 gammamol/dm(3). These DOC are unactive for physical and biological activities and are called refractory DOC. Concentration of the refractory DOC in the study area is consistent with the previous reported values for the Southern Ocean, which is about 41 mumol/dm(3). Based on the difference between the measured DOC concentration and the refractory concentration, the excess DOC concentration in the upper column can be calculated at every station. The excess DOC shows a spatial variability with a higher excess in the north of 64degreesS and little excess in the south of 64degreesS. In conclusion, DOC concentrations in the Prydz Bay and its nearby sea areas,are, consistent with the previous reported values in the Southern Ocean, which show a low DOC concentration with respect to the other oceans. Distribution of surface DOC concentrations in the study areas shows an increase from the southwestern to the northeastern, which is ascribed to the northern spread of continental shelf water from the Prydz Bay in summer. Contents of DOC and their distribution in the Prydz Bay and its nearby sea areas are mainly controlled by physical and biological processes.

关键词： The Prydz Bay Antarctica dissolved organic carbon

Variation of Electronic Structure with C Content in Si_(1-x-y)Ge_xC_y/Si(001) System

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1999年第4期15卷 296-298页

作者： Meichun HUANG Liqing WU and Zizhong ZHU(department of Physics, xiamen university,{2., china)To whom correspondence should be addressedE-mail: wlq@yanan. xmu. edu. cn xiamen Univ Dept Phys Xiamen 361005 Peoples R China

The electronic structures of strained Si 1-x-.Ge. C. (y<0.09) alloys on Si(001) have been studiedby the ab initio pseudopotential method within the local density functionaI theory. The variationsof the minim um band gap. the valence-band offset and the strain properties in the heterojunctioninterface are calculated together with the average bond energy theory. It is found that thedependences of the minimum band gap and the valence-band offset on the alloy compositionchange around the point of zero lattice mismatch. A comparison between our theoreticaf results and the available experimental data indicates that some of the contradictions from differentresearch groups can be reasonably explained.

关键词： Ge x-y)Ge_xC_y/Si System