港口服务系统的计算机仿真研究

把港口生产视为随机服务系统,建立了模拟港口营运状况的计算机仿真系统。港口吞吐量,航船的平均等时间,平均服务时间和平均排队长度等港口营运参数的模拟计算值与实际统计值基本一致,表明该仿真系统能够客观反映港口的实际营状况,可为港口建设和发展提供决策依据。     

猪场废水厌氧消化液好氧后处理过程亚硝化/硝化调控因素研究

采用序批式反应器（SBR）进行猪场废水厌氧消化液好氧后处理,研究后处理过程中亚硝化／硝化调控因素．在厌氧消化液中配入原水比例10％-30％（V／V）的试验中,配水比例越低,反应体系pH值越低,出水氨氮浓度越高,亚硝化率也越高．在曝气量100L／h-260L/h的条件下,曝气量越大,出水氨氮浓度越低,亚硝化率也越低．一个运行周期的监测数据反映出：曝气结束时氨氮浓度和溶解氧是影响硝化进程的主要因素．只要将曝气控制在氨氮刚好氧化完全时停止,即使大的曝气量也能达到高的亚硝化率（87％以上）,用硝化过程动力学常数能很好解释这种现象．在进水氨氮浓度524937mg／L范围内,进水氨氮浓度越高,出水氨氮浓度越高,但是亚硝化率平均值都在75％左右,说明进水NH3-N浓度对亚硝化率没有影响．试验结果表明：通过调控出水氨氮浓度和溶解氧可以将硝化进程控制在亚硝化阶段．     

电学问题中的边界元方法及计算机模拟

传输线的性能好坏直接影响着通信效果，由于工艺水平的限制，在各类传输线的制造中均可能出现偏差，采用边界元方法研究同轴电缆轴心偏离程度及对实际传输特性的影响问题，为传输线的制造提供了计算机模拟及相应的数据，并为数学上无法求出解析解的电学问题提供了一种可行的研究方法。     

不同吸附材质对毒死蜱和溴氰菊酯的净化效果分析

为探明玄武岩和沙子对稻田水体毒死蜱和溴氰菊酯的净化效果,使用玄武岩和沙子构建2个生态槽,然后将稻田水引入2个生态槽和1个静置槽,采用固相萃取仪-气相色谱法(ECD)对3个水槽中的水体进行跟踪监测.实验结果表明:采用程序升温、不分流进样的色谱条件建立的溴氰菊酯和毒死蜱的标准曲线相关系数高,重现性好,方法可用;沙子对毒死蜱...     

Cell-specific mitotic defect and dyserythropoiesis associated with erythroid band 3 deficiency

Most eukaryotic cell types use a common program to regulate the process of cell division. During mitosis, successful partitioning of the genetic material depends on spatially coordinated chromosome movement and cell cleavage. Here we characterize a zebrafish mutant, retsina (ret), that exhibits an erythroid-specific defect in cell division with marked dyserythropoiesis similar to human congenital dyserythropoietic anemia. Erythroblasts from ret fish show binuclearity and undergo apoptosis due to a failure in the completion of chromosome segregation and cytokinesis. Through positional cloning, we show that the ret mutation is in a gene (slc4a1) encoding the anion exchanger 1 (also called band 3 and AE1), an erythroid-specific cytoskeletal protein. We further show an association between deficiency in Slc4a1 and mitotic defects in the mouse. Rescue experiments in ret zebrafish embryos expressing transgenic slc4a1 with a variety of mutations show that the requirement for band 3 in normal erythroid mitosis is mediated through its protein 4.1R-binding domains. Our report establishes an evolutionarily conserved role for band 3 in erythroid-specific cell division and illustrates the concept of cell-specific adaptation for mitosis.