Distribution of CRH-and ACTH-like immunoreactive cells in amphioxus,Branchiostoma belcheri

Immunocytochemical studies on the nervous system,Hatschek's pit,digestive tract and gonads tissues of an amphioxus(Branchiostoma belcheri)were performed using polyclonal antibodies against human corticotrophin-releasing hormone(CRH)and human adrenocorticotropin(ACTH).The results showed that many CRH-like immunoreactive neurons were distributed specifically on the dorsal side and ventral side of brain vesicle,while a few CRH-like neurons and their fibers in spinal cord.At the same time,the epithelial cells in the basic region of Hatschek's pit were shown immunopositive to CRH antibody.In gonads(ovary and testis),CRH-immunopositive substance was localized in the cytoplasm near oocyte nucleus and in early spermatogenic cells.ACTH-like immunoreactivities were observed specially in the neurons and their protrusions localized on the ventral side of the brain vesicle and in spinal cord,and also in epithelial cells of Hatschek's pit,enteric neurons of digestive tract,oocytes in ovary and in early spermatogenic cells as well.It was found for the first time that CRH-like neurons existed in the middle region of brain vesicle(corresponding to the hypothalamus of vertebrates)and ACTH-like immunopositive cells existed in Hatschek's pit,implying that a control mechanism between brain vesicle and Hatschek's pit maybe had been already built in amphioxus as that in vertebrates.The present study will provide new morphological evidence for the origin and evolution of ACTH.In addition,the immunoreactivities of CRH and ACTH in the digestive tract and gonads suggested other physiological function of CRH and ACTH in amphioxus.     

Characteristics of Early Eocene radiolarian assemblases of the Sasa area, southern Tibet and their constraint on the closure history of the Tethys

Quantitative analysis of Early Eocene radiolarian assemblages discovered in the sedimentary melange （accretionary prism） of the Saga area, southern Tibet provides new information to constrain the timing of Tethys closure and the initial collision of India and Eurasia. The radiolarian species of Saga include Amphisphaera coronata （Ehrenberg）, Buryella hannae Bak ＆ Barwicz-Piskorz, Buryella clinata Foreman, Buryella tetradica Foreman, Calocycloma ampulla （Ehrenberg）, Lamptonium fabaeforme constrictum Riedel and Sanfilippo, Lamptonium pennatum Foreman, Lithomespilus coronatus Squinabol and Lamptonium （？） colymbus Foreman. The adequate and reliable correlation of these radiolarians specimens indicates that the assemblage is of Early Eocene in age. The age and depositional environment of these radiolarians testify that deep ocean basins existed between India Plate and Asia Plate during the Early Eocene. The complete closure of Tethys must have taken place at least after the Early Eocene.     

基坑变形及其安全性的随机预测

将基坑支护与周围土体视作一个不确定性系统，在对随机性很强的现场位移量实测数据建立提取趋势项和分离随机项方法的基础上，采用蒙特卡罗法建立了确定土性参数的随机反分析方法，由此得到可反映土体整体力学性质的不确定性参数。还据以建立了基坑变形的预测计算模型，包括预测基坑未来变形量的概率分布，及对基坑工程的安全性作概率意义上的判断。分析过程中，对土的流变性特征采用粘弹性本构模型进行了工程简化。提供的工程应用实例表明了此方法的可靠性。     

石墨形态对铸铁静海腐蚀性能的影响

分析了相同基体不同石墨形态的铸铁 ,在天然静海全浸条件下的腐蚀行为及其机理 ,静海中片状、球团状石墨的铸铁以较为均匀的全面腐蚀为主。球团状石墨铸铁的点蚀、坑蚀倾向大于片状石墨铸铁 ,具有最大的腐蚀深度     

一种采用步进电机的纠偏控制系统

介绍一种采用步进电机作为执行元件的纠偏控制系统，着重介绍偏差检测传感器、控制电路的结构、工作原理等。     

有限元法在深基坑支护中的应用

结合柱列式悬臂桩支护的工程实例 ,利用有限元法对桩身内力和变形进行了全过程分析 ,并对基坑开挖过程中支护结构的内力和变形进行了监测 ,对比理论分析和实验结果表明 ,有限元法比传统的极限平衡法更符合实际 .     

砼深受弯构件及圆形截面构件受剪承载力

结合 GBJ10 - 89混凝土结构设计规范修订课题 ,提出了混凝土深受弯构件和圆形截面偏压构件抗剪承载力的计算方法 .这些方法与试验资料吻合良好 ,并与矩形截面一般受弯构件的计算方法在一定程度上得到了统一 .     

城区工程爆破安全技术及管理

为了改善城区居民的生活环境，必须加快城市建设，在城市建设中经常要进行工程爆破。通过深孔扩奎爆破龙家山开发小区场地平整爆破工程中的实际应用，阐述了在城市中心地带及人口稠密地区的工程爆破中，采用适宜的爆破技术可显著地降低施工成本，加快工程进度，提高经济及社会效益，并对工程的安全生产及管理提出了一些建议。     

在用汽车排放状态监测管理系统的开发

随着汽车保有量的不断增加 ,汽车排放污染越来越引起人们的关注 ,本系统利用 VC 语言编程、Access建库对在用汽车的各种信息进行监测和管理 ,并能对所检测的数据信息进行多种统计分析 ,从中找出其污染物的排放规律 ,以切实加强对在用汽车的排放监测和管理 .     

基于小波变换的数字监控图像的噪声滤波方法

小波分析因具有多分辨率分析能力和时频局部化能力，在处理数字图像时占有很大优势.用小波变换技术的设计一种简单的实用性强的数字监控图像噪声滤波方法，在数字图像处理应用时效果理想.