磁流间断面类型的讨论

本文从电磁流体力学间断面关系式出发，引进了无量纲参数ρ1Hn^2/4πJ2，对各种磁流间断面进行了讨论，讨论了各种磁流间断面间相互转换的可能性。     

Pedo‐ecological consequences of lithological discontinuities in soils—examples from Central Europe

Soil profiles having lithological discontinuities, i.e., stratified or layered profiles, occur worldwide. Their genesis as part of the upper‐regolith formation is comparatively well understood, particularly in Central Europe where extensive research on relic periglacial cover beds has been done. But the pedogenetic and ecological implications of lithologically discontinuous soils (LDS) are less well known. Most textbooks rely on the so‐called A‐B‐C‐model as a climate‐driven approach to soil formation. After reviewing definitions and concepts of lithological discontinuities and how they form, we present a pedogenetic model extending the traditional approach by considering substrate genesis and regolith dynamics. The consequences in the interpretation of vertical distributions of parameters of soil acidification and of heavy metals are investigated for typical soil profiles from the W Ore Mountains and the central‐German lowlands. Results show how lithological discontinuities influence the depth gradients and that properties inherited from substrate should be distinguished, if possible, from those developed by pedogenesis.     

异源抗体对接方法预测流感病毒血凝素B细胞构象表位

为了对异源抗体对接方法预测流感病毒血凝素B细胞构象表位的可行性进行分析,本研究基于蛋白质相互作用界面的形状互补理论,使用异源抗体(来自于抗原抗体复合物1G9M、1RVF、1TPX、1NCA、1A2Y)的晶体结构同流感病毒血凝素(A/Aichi/2/68(H3N2))的晶体结构进行刚性分子对接,通过计算B细胞表位的预测表面和实际表面C-α原子之间的RSMD以及表位氨基酸的准确率,分析用异源抗体探测出血凝素B细胞表位的可能性。结果表明,不同的异源抗体均可结合到A/Aichi/2/68(H3N2)的已知B细胞表位,最佳的对接构象与原晶体结构重叠后表位残基C-α原子的均方根偏差均小于0.6埃,表位氨基酸预测的准确性大于60%,说明异源抗体对接方法可以尝试用于B细胞构象表位的预测。     

昆明裂腹鱼不同组织乳酸脱氢酶同工酶研究

采用不连续聚丙烯酰胺凝胶电泳法,对昆明裂腹鱼的眼球、心脏、肾脏、性腺、脾脏、肝胰脏、脑、鳃和肌肉等9种组织的乳酸脱氢酶同工酶(LDH)进行了测定。结果表明:昆明裂腹鱼LDH共有15条酶带表现出特异性,在不同组织中检出的LDH酶带数量不同,以肝胰脏中最多,共检出9条;在酶活性方面,LDH在脑、鳃、肌肉和肾脏等组织中活性最强,而在眼球组织中最弱。     

泵站前池非连续挑流消能防沙技术措施

通过前池水力过流情况分析和改造前现场试验,发现前池流态紊乱导致了田山一级泵站机组的剧烈振动和颤振.提出了由非连续底坎、非连续挑流墩和两道压水板组成的非连续挑流消能防沙技术措施,并对改造后泵站的运行情况进行了现场试验.试验结果表明,采用技术措施改造后,前池、进水池流态和水泵进水条件得到了显著的改善,池中断面流速分布趋于均匀且断面紊动能量明显降低;测试机组单泵流量平均提高了0.14 m3/s,水泵效率平均提高了4.99%,泵站装置效率平均提高了3.88%;消除了泵体颤振,使水泵喇叭口振动标准由4.5级烈度降低到1.8级烈度;减缓了前池和进水池泥沙淤积,使试验前池和进水池清淤时间由改造前的运行800h延长至改造后的运行1 300 h,防沙效果良好.非连续挑流消能防沙措施为多泥沙河流泵站技术改造提供了一种简单有效的方法.     

不连续气体交换循环呼吸模式下西藏飞蝗和东亚飞蝗的呼吸特征参数

为解析西藏飞蝗对青藏高原干燥低氧环境的呼吸适应机制,本研究比较不连续气体交换循环(discontinuous gas exchange,DGC)呼吸模式下西藏飞蝗Locusta migratoria tibetensis与东亚飞蝗L.m.manilensis的呼吸特征参数。结果表明:西藏飞蝗和东亚飞蝗4、5龄蝗蝻及雄成虫均采用DGC呼吸模式,且雄成虫呼吸速率的峰值和周期比其4、5龄蝗蝻更稳定;西藏飞蝗4龄蝗蝻DGC历时为13.75 min,显著高于东亚飞蝗的6.46 min,而其5龄蝗蝻和雄成虫DGC历时分别为7.46 min和8.53 min,显著低于东亚飞蝗的15.70 min和14.44 min;西藏飞蝗4、5龄蝗蝻的暴发间期历时所占比例分别为7.40%和26.70%,显著低于东亚飞蝗4、5龄蝗蝻(分别为22.20%和67.20%),其雄成虫暴发间期历时所占比例为79.20%,显著高于东亚飞蝗雄成虫的53.60%;西藏飞蝗4、5龄蝗蝻和雄成虫代谢率分别为3.92、3.81和2.90 W/kg,与东亚飞蝗4、5龄蝗蝻和雄成虫差异不显著(分别为4.27、3.45和3.07 W/kg)。西藏飞蝗分布于低氧高海拔青藏高原,其DGC历时和暴发间期历时所占比例异于东亚飞蝗,表明DGC呼吸模式与其对高原环境的适应有关。     

Local convergence zones or discontinuous lines in the Taklimakan Desert, Northwest China

In order to study convergence zones or discontinuous lines formed locally in the Taklimakan Desert,we analyzed available MODIS images onboad TERRA or AQUA satellite for ten cases:29 March 2002,14 April 2002;2 January 2003;21 April 2003;26 March 2004;28 April 2004;30 January 2005;25 June 2005;3 December 2005;and 26 July 2006.We used weather maps published by the Japan Mete-orological Agency for the Asia and Pacific region at 500 hPa,700 hPa and 850 hPa,at 00Z and 12Z to analyze the meteorological conditions occurring in each case.We estimated the positions of air streams,convergence zones or discontinuous lines between them,and thermal conditions on the maps and con-firmed the presence of cumulus and cumulonimbus clouds through satellite images in particular.After a review of previous studies,this paper introduced the results of the present study.Closed warm areas in the Taklimakan Desert and on the Tibetan Plateau and local convergence zones or discontinuous lines in the Taklimakan Desert were discussed together with their diurnal changes,using composite maps of the ten cases.Along the long axis of the desert the convergence zones or discontinuous lines normally extend 70-80 km in a west-east direction,but are suspected to exceed 100 km in extreme cases.On the other hand,the convergence zones or discontinuous lines extending in a north-south direction on the southern fringe of the desert have a length of 40-60 km.The closed warm areas show clear diurnal changes,but they were not detected at the 500 hPa level.An example of a clear convergence zone running in a north-south direction on 26 July 2006 was presented in detail with corresponding satellite images.     

水平荷载作用下单桩的虚拟桩解法及参数

根据Muki&Sternberg的虚拟桩方法,将水平荷载作用下单桩的问题分解为弹性半空间扩展土和一根虚拟桩的叠加,其中虚拟桩的弹性模量等于桩的弹性模量与土的弹性模量之差。基于水平位移协调条件推导出求解桩土间相互作用所需要的第二类Fredholm积分方程,通过广义胡可定律推导出该积分方程间断点的显式解,从而提高了Fredholm积分方程的数值计算精度并简化了计算程序的编写,根据Mindlin解推导出位移影响函数,简化了位移函数的推导过程。参数分析表明,桩土弹性模量比对单位水平力作用下桩身最大弯矩的位置有明显的影响,随着桩刚度的增加,桩身最大弯矩的位置随之加深。     

TGEV细胞培养物超速离心与RT-PCR扩增的研究

研究猪传染性胃肠炎病毒(TGEV)细胞培养物的超速离心及鉴定方法.将TGEV的细胞培养物用饱和硫酸氨法浓缩后,用200 g/kg～500 g/kg蔗糖密度梯度离心分装,测定蛋白浓度并取峰值管进行RT-PCR,并设立15、25、35三个不同循环参数测定PCR产物volume值.结果表明,在35个循环条件下第14号样品PCR产物的volume值最大,表明该样品病毒核酸的含量最大,由此推算病毒粒子主要集中在360 g/kg～380 g/kg蔗糖区带处,这与理论值相符,证明猪传染性胃肠炎病毒经密度区带离心后,利用PCR产物量确定目的病毒区带效果显著.     

大步甲的分子系统与进化模式

大步甲主要分布于北半球,全世界大约有1000余种。因大步甲后翅退化,不能飞行,其移动能力和扩散范围都受到很大程度的限制,因此,容易产生地理隔离和遗传分化,从而成为研究物种分化和生物多样化的好材料。近年来,通过对大步甲分子系统的详细研究,不仅很大程度上解明了大步甲各分类群间的系统发育关系,而且对大步甲的系统演化过程和形态进化模式也有了较深的理解,获得了很多重要的见解。在此做一个简单的综述。