Two fishing methods including gillnetting and trawling to estimate attributes of fish assemblage were compared in Dianshan Lake from August 2009 to July 2010. Species composition dif fered significantly between the ge...Two fishing methods including gillnetting and trawling to estimate attributes of fish assemblage were compared in Dianshan Lake from August 2009 to July 2010. Species composition dif fered significantly between the gears, with four significant contributors in gillnet catches and one in trawl catches. Trawling collected more proportions of benthic species by number and biomass than gillnetting. Size distribution was significantly influenced by fishing technique; gillnetting captured relatively less small-sized fishes and trawling captured less large-sized individuals. Trawling produced species richness closer to the one expected than gillnetting. On the whole, trawl catch was a quadratic polynomial function of gillnet catch and a significantly negative correlation was found between them, both of which varied as dif ferent polynomial functions of temperature. However, trawl and gillnet catches were significantly correlated only in one of five month groups. It is concluded that single-gear-based surveys can be misleading in assessments of attributes of fish assemblages, bottom trawling is a more ef fective gear for assessing fish diversity than benthic gillnetting, and using gillnet catches as an indicator of fish density depends on fishing season in the lake.展开更多
Nucleotide sequences from 18S rDNA of 11 ostracodes, which represent four suborders and six superfamilies of podocopidan, were determined. The phylogenetic relationships were analyzed based on three kinds of methods (...Nucleotide sequences from 18S rDNA of 11 ostracodes, which represent four suborders and six superfamilies of podocopidan, were determined. The phylogenetic relationships were analyzed based on three kinds of methods (maximum-likelihood, maximum-parsimony, and neighbor-joining), and the three topologies gained were basically similar. The results have showed that (1) a monophyletic Podocopida was supported strongly; (2) the phylogenetic relationships of four suborders were (Darwinulocopina plus (Bairdiocopina plus (Cytherocopina plus Cypridocopina))), which indicated that a close relationship between Cytherocopina and Cypridocopina, and Darwinulocopina had separated early from the main podocopinan; (3) Cypridocopinan formed a monophyletic group, among which the phylogenetic relationship of three superfamilies was (Cypridoidea plus (Macrocypridoidea plus Pontocypridoidea)).展开更多
The preparation of lead-free thick-film resistors are reported:using RuO 2 and ruthenates as conductive particles,glass powders composed of B 2 O 3,SiO 2,CaO and Al2 O 3 as insulating phase,adding organic matter which...The preparation of lead-free thick-film resistors are reported:using RuO 2 and ruthenates as conductive particles,glass powders composed of B 2 O 3,SiO 2,CaO and Al2 O 3 as insulating phase,adding organic matter which mainly consists of ethyl cellulose and terpineol to form printable pastes.Resistors were fabricated and sintered by conventional screen-printing on 96%Al 2 O 3 substrates,and then sintering in a belt furnace.X-ray diffraction(XRD) and electron scanning microscopy(SEM) have been used to characterize the conductive particles.The resistors exhibit good refiring stability and low temperature coefficient of resistance.Sheet resistance spans from about 80Ω/□ to 600Ω/□.The resistors prepared are qualified for common use.展开更多
目的探讨青春期血清丙氨酸氨基转移酶(ALT)浓度与血压[收缩压(SBP)、舒张压(DBP)]水平的关系,为青春期人群慢性病区域性防控体系的建立提供一定理论依据。方法2018年2月至2019年6月,以深圳市9所中学的初一和高一学生为研究对象,按照性...目的探讨青春期血清丙氨酸氨基转移酶(ALT)浓度与血压[收缩压(SBP)、舒张压(DBP)]水平的关系,为青春期人群慢性病区域性防控体系的建立提供一定理论依据。方法2018年2月至2019年6月,以深圳市9所中学的初一和高一学生为研究对象,按照性别、年龄(10~13岁、14~17岁)和血清ALT四分位数分层后,分析血清ALT水平与血压的关系。结果7805例青少年中,平均SBP为(112.87±12.00)mmHg,平均DBP为(71.68±9.61)mmHg。男生组血压高于女生组,SBP为(115.81 vs 109.23)mmHg,DBP为(73.15 vs 69.86)mmHg(P<0.001);按血清ALT水平的四分位数分层分析显示,随ALT水平等级数值增长血压呈增长趋势(P<0.001);广义相加模型显示青少年人群血压与血清ALT水平呈相关关系,SBP-ALT(r=0.113~0.279,P<0.001),DBP-ALT(r=0.088~0.208,P<0.001);二分类logistic回归分析显示,青少年人群的高血压与血清ALT升高(OR=3.411,95%CI:2.215~5.251)及男性(OR=3.684,95%CI:2.594~5.231)有关联。结论青春期血压升高与血清ALT升高存在关联性,当地政府应提高监测中学生血压及ALT同步升高情况的警惕性。展开更多
Monodispersed magnetite Fe3O4 and hematite α-Fe2O3 nanocrystals have been grown in co-solvents of alcohol and water. Either the shape or the size of the nanocrystals could be easily controlled. Both the phases and na...Monodispersed magnetite Fe3O4 and hematite α-Fe2O3 nanocrystals have been grown in co-solvents of alcohol and water. Either the shape or the size of the nanocrystals could be easily controlled. Both the phases and nanostructures have been characterized by powder X-ray diffraction patterns and electron microscopy. The magnetic and catalytic properties of these products were investigated and compared with each other. The obtained results clearly demonstrate that these iron oxide nanocrystals are soft ferromagnetic at room temperature and α-Fe2O3 has a more effective catalytic property on the thermal decomposition of ammonium perchlorate than Fe3O4. Based on the experimental data, it is proposed that the magnetic and catalytic properties of these nanocrystals are dependent not only on the size and shape, but also on the surface structure of the nanocrystals. The nanoplates with significant anisotropic nanostructure demonstrate a highly enhanced performance as compared to nanoparticles.展开更多
基金Supported by the Science and Technology Commission of Shanghai Municipality(Nos.08DZ1203101,08DZ1203102)the Shanghai University Knowledge Service Platform,Shanghai Ocean University Aquatic Animal Breeding Center(No.ZF1206)
文摘Two fishing methods including gillnetting and trawling to estimate attributes of fish assemblage were compared in Dianshan Lake from August 2009 to July 2010. Species composition dif fered significantly between the gears, with four significant contributors in gillnet catches and one in trawl catches. Trawling collected more proportions of benthic species by number and biomass than gillnetting. Size distribution was significantly influenced by fishing technique; gillnetting captured relatively less small-sized fishes and trawling captured less large-sized individuals. Trawling produced species richness closer to the one expected than gillnetting. On the whole, trawl catch was a quadratic polynomial function of gillnet catch and a significantly negative correlation was found between them, both of which varied as dif ferent polynomial functions of temperature. However, trawl and gillnet catches were significantly correlated only in one of five month groups. It is concluded that single-gear-based surveys can be misleading in assessments of attributes of fish assemblages, bottom trawling is a more ef fective gear for assessing fish diversity than benthic gillnetting, and using gillnet catches as an indicator of fish density depends on fishing season in the lake.
基金supported by the Major Project of the National Natural Science Foundation of China under contract No.30130040the Cultivation Fund of the Key Scientific and Technical hmovation Project,Ministry of Education of China under contract No.704023+2 种基金E-institute of Shanghai Municipal Education Commission under contract No.E03009the Program of Shanghai Subject Chief Scientist under contract No.05XD14005 to Chen Liqiaothe PhD Program Scholarship Fund of ECNU 2005.
文摘Nucleotide sequences from 18S rDNA of 11 ostracodes, which represent four suborders and six superfamilies of podocopidan, were determined. The phylogenetic relationships were analyzed based on three kinds of methods (maximum-likelihood, maximum-parsimony, and neighbor-joining), and the three topologies gained were basically similar. The results have showed that (1) a monophyletic Podocopida was supported strongly; (2) the phylogenetic relationships of four suborders were (Darwinulocopina plus (Bairdiocopina plus (Cytherocopina plus Cypridocopina))), which indicated that a close relationship between Cytherocopina and Cypridocopina, and Darwinulocopina had separated early from the main podocopinan; (3) Cypridocopinan formed a monophyletic group, among which the phylogenetic relationship of three superfamilies was (Cypridoidea plus (Macrocypridoidea plus Pontocypridoidea)).
文摘The preparation of lead-free thick-film resistors are reported:using RuO 2 and ruthenates as conductive particles,glass powders composed of B 2 O 3,SiO 2,CaO and Al2 O 3 as insulating phase,adding organic matter which mainly consists of ethyl cellulose and terpineol to form printable pastes.Resistors were fabricated and sintered by conventional screen-printing on 96%Al 2 O 3 substrates,and then sintering in a belt furnace.X-ray diffraction(XRD) and electron scanning microscopy(SEM) have been used to characterize the conductive particles.The resistors exhibit good refiring stability and low temperature coefficient of resistance.Sheet resistance spans from about 80Ω/□ to 600Ω/□.The resistors prepared are qualified for common use.
文摘目的探讨青春期血清丙氨酸氨基转移酶(ALT)浓度与血压[收缩压(SBP)、舒张压(DBP)]水平的关系,为青春期人群慢性病区域性防控体系的建立提供一定理论依据。方法2018年2月至2019年6月,以深圳市9所中学的初一和高一学生为研究对象,按照性别、年龄(10~13岁、14~17岁)和血清ALT四分位数分层后,分析血清ALT水平与血压的关系。结果7805例青少年中,平均SBP为(112.87±12.00)mmHg,平均DBP为(71.68±9.61)mmHg。男生组血压高于女生组,SBP为(115.81 vs 109.23)mmHg,DBP为(73.15 vs 69.86)mmHg(P<0.001);按血清ALT水平的四分位数分层分析显示,随ALT水平等级数值增长血压呈增长趋势(P<0.001);广义相加模型显示青少年人群血压与血清ALT水平呈相关关系,SBP-ALT(r=0.113~0.279,P<0.001),DBP-ALT(r=0.088~0.208,P<0.001);二分类logistic回归分析显示,青少年人群的高血压与血清ALT升高(OR=3.411,95%CI:2.215~5.251)及男性(OR=3.684,95%CI:2.594~5.231)有关联。结论青春期血压升高与血清ALT升高存在关联性,当地政府应提高监测中学生血压及ALT同步升高情况的警惕性。
基金supported by the National Natural Science Foundation of China, Guangdong Province, Guangzhou Citythe Ph.D. Programs Foundation of Ministry of Education of China (U0734002, 50872158, 8251027501000010, 2010GN-C011 & 20090171110025)
文摘Monodispersed magnetite Fe3O4 and hematite α-Fe2O3 nanocrystals have been grown in co-solvents of alcohol and water. Either the shape or the size of the nanocrystals could be easily controlled. Both the phases and nanostructures have been characterized by powder X-ray diffraction patterns and electron microscopy. The magnetic and catalytic properties of these products were investigated and compared with each other. The obtained results clearly demonstrate that these iron oxide nanocrystals are soft ferromagnetic at room temperature and α-Fe2O3 has a more effective catalytic property on the thermal decomposition of ammonium perchlorate than Fe3O4. Based on the experimental data, it is proposed that the magnetic and catalytic properties of these nanocrystals are dependent not only on the size and shape, but also on the surface structure of the nanocrystals. The nanoplates with significant anisotropic nanostructure demonstrate a highly enhanced performance as compared to nanoparticles.
