中国对虾(Penaeus chinensis)幼体血液循环的活体观察

溞对中国对虾早期幼体的循环系统及血液流向进行了活体观察 ,描述了中国对虾早期幼体发育阶段中幼体循环系统血管的走向与分布、血液的流向及循环路径等 ,比较各期幼体循环系统的形态 ,并探讨对虾早期幼体循环系统的发育过程。     

羊栖菜茎部愈伤组织再生苗的解剖学研究

利用石蜡切片法对羊栖菜纵裂主枝上愈伤组织再生苗的发生过程进行了形态解剖学观察。发现此种成苗方式是在主枝 (茎 )或假根处由外皮层分裂形成愈伤组织 ,再由愈伤组织分化成苗的一种无性繁殖方式。愈伤组织形成再生苗有望成为羊栖菜人工养殖种苗的来源之一。     

二(甲基环戊二烯)钐氯化物合成和晶体结构研究

作者以 Sm Cl3 与 (CH3 Cp) Na反应分离得到了三价稀土有机配合物 [(CH3 Cp) 2 Sm Cl·THF]2 的单晶 ,X-射线四圆衍射测定 ,该配合物属正交晶系 ,Pbna空间群 ,晶胞参数 a=9.6 6 2 (2 ) ,b=16 .4 76 (9) ,c=2 0 .582 (9) ;α=β=γ=90°,Z=4。并分析比较 [(CH3 Cp) 2 Sm Cl· THF]2 与其他三价稀土一氯化物的结构特点     

Modeling lateral circulation and its influence on the along-channel flow in a branched estuary

A numerical modeling study of the influence of the lateral flow on the estuarine exchange flow was conducted in the north passage of the Changjiang estuary. The lateral flows show substantial variabilities within a flood-ebb tidal cycle. The strong lateral flow occurring during flood tide is caused primarily by the unique cross-shoal flow that induces a strong northward (looking upstream) barotropic force near the surface and advects saltier water toward the northern part of the channel, resulting in a southward baroclinic force caused by the lateral density gradient. Thus, a two-layer structure of lateral flows is produced during the flood tide. The lateral flows are vigorous near the flood slack and the magnitude can exceed that of the along-channel tidal flow during that period. The strong vertical shear of the lateral flows and the salinity gradient in lateral direction generate lateral tidal straining, which are out of phase with the along-channel tidal straining. Consequently, stratification is enhanced at the early stage of the ebb tide. In contrast, strong along-channel straining is apparent during the late ebb tide. The vertical mixing disrupts the vertical density gradient, thus suppressing stratification. The impact of lateral straining on stratification during spring tide is more pronounced than that of along-channel straining during late flood and early ebb tides. The momentum balance along the estuary suggests that lateral flow can augment the residual exchange flow. The advection of lateral flows brings low-energy water from the shoal to the deep channel during the flood tide, whereas the energetic water is moved to the shoal via lateral advection during the ebb tide. The impact of lateral flow on estuarine circulation of this multiple-channel estuary is different from single-channel estuary. A model simulation by blocking the cross-shoal flow shows that the magnitudes of lateral flows and tidal straining are reduced. Moreover, the reduced lateral tidal straining results in a decrease in vertical stratification from the late flood to early ebb tides during the spring tide. By contrast, the along-channel tidal straining becomes dominant. The model results illustrate the important dynamic linkage between lateral flows and estuarine dynamics in the Changjiang estuary.     

大中小震与抗震设防标准

讨论二级抗震设计与超越概率标准、概率法与综合概率法给出的3个水平的地震动的关系. 通过危险性分析的实际例子,讨论了50年超越概率2%、10%和63%的地震动,即大震、中震和小震的相对大小关系,并提出抗震设防标准的确定方法.     

2017—2021年长江天鹅洲故道鱼类群落结构变化、成因分析及对长江江豚迁地保护的启示

长江天鹅洲故道是长江江豚首个迁地保护区,其中充足而适口的饵料鱼类资源是长江江豚种群健康发展的保障。为此,根据2017年10月—2021年4月对长江天鹅洲故道进行的7次鱼类调查数据,结合禁捕前的历史数据,对其鱼类群落结构演变进行了分析,并针对长江江豚饵料鱼的供应状况对天鹅洲故道内鱼类资源管理提出了建议。调查期间,共采集到鱼类57种,其中,蒙古鲌(Culter mongolicus)、鲢(Hypophthalmichthys molitrix)和鳙(Aristichthys nobilis)等大中型鱼类生物量明显增加,而?(Hemiculter leucisculus)和似鳊(Pseudobrama simoni)等小型鱼类生物量呈现下降趋势。鱼类群落优势种逐渐由太湖新银鱼(Neosalanx taihuensis)、短颌鲚(Coilia brachygnathus)和?等小型鱼类转变为鳙、蒙古鲌和拟尖头鲌(Culter oxycephaloides)等大中型鱼类,尤其是新近出现的拟尖头鲌种群发展迅速。同时,短颌鲚和?等小型鱼类的体重在减小,而鲢、鳙等大中型鱼类规格在持续提高。长江江豚以小...     

Discovery of the Natural Deformation Vestige of Gaixia Remains,Guzhen County,Anhui Province,China and Its Implications

Recognition of natural deformation during the excavation of ancient remains and tombs is important for tracing or enriching historic and prehistoric deformation records. Recently, the earthquake agencies,in cooperation with the cultural relics and archaeological institutions, conducted a special excavation investigation to the Gaixia remains archaeological scene in Guzhen,Anhui Province. Faults and fissures were discovered there, which,as demonstrated by the preliminary study,are the traces of two stratum d...     

国家安全发展示范城市建设的震灾预防对策研究

我国地震多、强度大、分布广,强地震的现实危害和潜在威胁是我国城市安全发展所面临的重大挑战。国内外城市地震灾害惨痛经验表明,震灾预防能力建设不足的城市往往在强震中毁于一旦。实现我国城市安全可持续发展,必须高度重视和持续推进城市震灾预防能力建设,切实防控和消除地震灾害风险。本文在深入分析城市地震灾害影响因素的基础上,从震灾预防能力建设、城市地震灾害风险防控工作、法规及技术标准和评价体系等方面入手,提出了进一步加强城市震灾预防能力建设的对策建议。     

2013-2016年乳山震群b值深度变化特征及意义

利用双差定位方法,对2013年10月—2016年12月乳山震群进行重定位,并计算乳山震群中地震集中活动区域b值,分析其深度分布变化。结果显示：地震重定位后表现为近NW向集中分布;b值在震源深度7.4 km上下最小,反映该深度处应力最强;乳山震群b值并不随震源深度增大而呈系统性减小变化,且深度10.2 km以下无有效b值,进一步证实该震群近NW向发震断裂的存在。根据b值随深度的变化特征,推测断裂活动的高应力区域集中在6.5—10.2 km深度范围内,断裂活动在深度7.4 km处应力最强,且水平分布最广;相比上下两侧地壳介质b值在5.5—6.2 km深度层位明显增大,反映该深度层位介质性质存在明显差异。