Significant effects of fishing gear selectivity on fish life history

Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual’s traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectiv-ity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. Ac-cording to the existing tend of exploited fish individual’s life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.     

压力驱动条件下页岩微纳米孔隙CO2/CH4竞争吸附特性

流动状态下的CO2/CH4竞争吸附特性对高效开采页岩气具有重要作用.引入吸附选择性系数和置换效率,建立石墨烯微纳米孔隙模型,采用非平衡分子动力学方法,在压力驱动条件下,模拟微纳米孔隙中注入压力、温度及压差对CO2/CH4二元混合物竞争吸附行为的影响.结果表明:CO2吸附能力强于CH4,流动状态下吸附选择性系数和置换效率与注入压力呈正比,与温度呈反比;流动状态下的CO2/CH4的吸附选择性较无流动时的低.该结果为研究页岩储层中CO2/CH4竞争吸附机理提供依据.     

An Inverse Analysis of the Comprehensive Medium Parameters and a Simulation of the Crustal Deformation of the Qinghai-Tibet Plateau

sedonthetheoryoffiniteelementanalysis,aninverseanalysismodelforthecomprehensivemediumparametersoftheQinghai-TibetPlateauissetup.WiththehelpofGPSvelocityfield,thecomprehensivecrustalmediumparametersoftheplateauareinverselyanalyzedandthecharacteristicsoftherelatedmovementmacroscopicallysimulated.ItisthenconcludedthatthetectonicdeformationoftheplateauismainlyintheformofaN-ScompressionaccompaniedbyanE-Wstretching,andthepresenttectonicsettingoftheplateaushouldbetheresultofthecollisionbetweentheIndianandtheEurasiancontinentsduringtheCenozoic.     

新疆罗布泊地区嗜盐细菌的分离及其嗜盐特性

从罗布泊"大耳朵"地区盐壳中分离获得108株嗜(耐)盐细菌.试验比较了不同培养基的分离效果,测定了嗜(耐)盐细菌对NaCl的耐受性,生长pH范围及对Na+、K+、Mg2+、Ca2+的选择性.结果表明,添加罗布泊盐壳浸提物的CM改良培养基更有利于嗜(耐)盐细菌的富集培养和分离.罗布泊嗜盐细菌中以革兰氏阴性菌、杆菌为主,大多具有产生色素的特性.大多菌株的pH生长范围是6.0～10.0,最适生长pH值是7.0～8.0.根据生长的NaCl浓度,将分离菌株划分为中等嗜盐细菌、极端嗜盐细菌和耐盐细菌,所占比例分别为24%,27%,49%.嗜(耐)盐细菌的分布与组成类型与分离地点的含盐量有一定的相关性.多数嗜盐细菌对Na+、K+、Mg2+有广泛的适应性,生长所需的Na+可以被一定浓度的K+、Mg2+替代,但缺乏对Ca2+的适应性.多数耐盐细菌对Na+、K+、Mg2+、Ca2+的选择性不强.少数嗜(耐)盐细菌对Na+、K+、Mg2+、Ca2+具有专一的选择适应性.     

从雷击的选择性谈雷电防御

通过对雷击选择性的探讨,提出在日常生活中怎样更好地防御雷电.     

气体选择性吸收的透过度计算

当太阳短波和地气系统长波辐射在地气中传输时,在各种形式的衰减中,气体的选择性吸收很重要,它由吸收气体万分、吸收气体状态参数等决定,在反演大气温度和大气吸收成分含量以及计算地球大气的加热冷却等方面都有重要作用。本文的内容主要是气体选择性吸收透地率的各种计算方法。     

Experimental study of the selective adsorption of heavy metals onto clay minerals

The interaction between minerals and heavy metals has been a hot object of study in environmental science,mineralogy and soil science,Through the selective adsorption experiment of Ca-montomorillonite,illite and kaolinite to Cu2 ,Pb^2 ,Zn^2 ,Cd^2 ,and Cr^3 ions at certain conditions,it could be concluded that Cr^3 is most effectively sorbed by all the three minerals.Also,it can be found that Pb^2 shows a strong affinity for illite and kaolinite while cu^2 for montmorillonite .Based on the adsorption experiment at varying pH of solution,it can be found that the amount of heavy etals sorbed by minerals increases with increasing pH of the solution.     

火山岩储层斜长石选择性溶蚀的岩石学及热力学研究

长石溶孔是火山岩中重要的孔隙类型之一,火山岩的主要孔隙类型中长石溶孔所占的比例在1.24%～60.61％之间,在储层中占有重要地位。从岩相学、岩石化学CIPW标准矿物成分、热力学等方面论证了斜长石的选择性溶蚀。岩相学特征表现出斜长石选择性溶蚀的特征,即钙长石溶蚀时钠长石没有溶蚀,同时出现斜长石选择性溶蚀时钠长石和钾长石生长的现象。斜长石选择性溶蚀得到了CIPW标准矿物成分的支持,在CIPW标准矿物成分中长石的端元组分主要为钠长石和钾长石,而钙长石绝大多数为0或接近0。热力学研究表明,在同样的温度、压力和地层水成分的条件下,在斜长石中优先溶解钙长石组分。当地层水中Na+和K+浓度达到饱和时发生钠长石和钾长石沉淀,出现斜长石选择性溶蚀的同时发生钠长石和钾长石生长的现象。     

基于视知觉金字塔模型的专题地图视觉层次设计

专题地图往往需要表达制图专题的空间分布特征、数量特征、时间变化特征等多层次的内容,故清晰的视觉层次对专题地图的信息表达至关重要.将视知觉金字塔模型和视觉选择性原理与专题地图的内容层次和图面表达视觉层次进行耦合,建立了"内容层次设计-视觉注意-视觉变量设计"的理论框架.在此基础上,以《深圳市历史风貌区和历史建筑》专题地图...     

胶结壳有孔虫对长石的选择性利用

文章采用扫描电镜、红外光谱、拉曼光谱、粒度分析等方法对浙江台州大港湾滨海沉积物中的胶结壳有孔虫亚洲波斯基砂虫（Polskiammina asiatica）和抱球砂抱球虫（Ammoglobigerina globigeriniformis）的壳壁进行了分析。结果表明，两种有孔虫壳壁具有相似的物质组成，主要包括矿物颗粒、有机外膜、有机内壁衬层、覆盖矿物的有机膜和连接矿物的丝状有机质。构筑壳壁的矿物主要有石英、长石和高岭石，有机物主要为酸性糖蛋白和脂肪。两种有孔虫倾向于选取沉积物中粒径较小的矿物，矿物粒径分布范围较小。壳壁中长石集中分布于有孔虫中心和外壁，很少出现于房室之间的隔板中。分析认为，壳壁曲率和矿物成分制约了长石的特异性分布，而长石的特异性分布有利于提高壳壁稳定性和有孔虫对能量及营养元素的获取。