The Effect of Slabs on the Failure Mode of Reinforced Concrete Frame Structures

A majority of reinforced concrete frame structure failure patterns resulting from the May 12, 2008 earthquake in Wenchuan County, P. R. China were analyzed. It was found that the main failure mode of frame works was “strong beam, weak column”, which conflicts with the design criteria of “strong column, weak beam”. The cause of this failure pattern was analyzed. A new concept is put forward that should be considered in design work. The over strength caused by slabs connected monolithically to the beams is analyzed. The joint types, transverse beam stiffness and lateral drift influence the reinforcing effect of the sla, Moreover, a reinforced concrete frame model was simulated using the program ABAQUS. The slab reinforcement stress distributions at different lateral drifts were analyzed and the effective flange width value proposed.     

中亚热带侵蚀黄壤坡地润楠次生林的群落结构特征

为了探讨中亚热带侵蚀黄壤坡地植被恢复模式的群落结构,以武陵山区女儿寨小流域为例,运用群落生态学的研究方法对润楠次生林的垂直层次结构、种群水平分布格局、乔木层直径与树高分布结构进行了研究.结果表明:润楠次生林群落层次结构分化明显,可分为乔木层、灌木层、草本层及层外植物4个基本层次,物种数量排序为灌木层(23种)草本层(19种)乔木层(16种).乔、灌、草重要值在10以上的主要种群有7个,其水平分布格局以聚集分布占绝对优势,占主要种群的71.43%.β分布和r分布能较好地模拟乔木层直径与树高分布结构,径阶与树高分布曲线反映乔木层中小径阶、矮小林木占多数.多数种群的聚集分布有利于促进黄壤坡地的植被恢复与重建过程,但润楠次生林林分质量较低,应辅之以积极的人工措施来改善群落结构,以充分发挥其坡地水土流失治理等功能.     

东亚钳蝎神经毒素BmK CT三维结构分子建模及晶体生长条件的初步筛选

东亚钳蝎是一类广泛分布于我国且具有重要药用价值的野生资源.其氯离子通道神经毒素(BmK CT)对人脑神经胶质瘤细胞具有靶向特异性的抑制作用.利用SWISS-MODEL服务器对BmK CT进行蛋白质原子结构的同源建模,利用Insight II软件包对建模结果做能量最小化和分子动力学优化,获得最佳候选模型.三维结构对比分析表明,BmK CT与以色列蝎氯通道毒素(Cltx)三维结构极为相似,均由一个α-helix和两个反向平行的β-sheet构成,但BmK CT属于βαβ型,而Cltx属于αββ型.表面静电势分析表明,BmK CT和Cltx分子表面分布着大量正电势,暗示两分子功能相似,且其中的碱性氨基酸及产生的正电势对其与受体结合起决定作用.采用晶体生长试剂盒(Crystal Screening Kit)中的51个缓冲液配方筛选BmK CT的结晶条件,在7号配方(1.4 mol/L 乙酸钠,0.1 mol/L 甲次砷酸钠,pH 6.51中筛选到柱状六边形晶体.     

动词基本结构的建立及对汉语句子英译的意义

对题元角色的把握,有助于确定抽象句子中动词的配价情况以及空语类,进而建立起类的、潜在的、静态的、抽象的、具有概括性的动词基本结构（深层结构）。反过来,动词基本结构的建立,可以指导我们把握具体语句的题元角色、动词配价和空语类,有助于把握动词结构各种动态的、具体的变式（表层结构）。动词基本结构的建立对汉语句子的英译有着重要的指导意义。     

黄瓜叶片大小解剖结构的对比研究

通过制作石蜡切片对4个黄瓜品种在3个时期的解剖结构进行了观察。其中D9320、D2005为叶面积大品种,D0455、D0401为叶面积小品种。结果表明,D9320、D2005叶面积大的原因是细胞平均面积大,而非数量多;D0401、D0455叶面积小的原因是细胞平均面积小,而非数量少。黄瓜叶为典型异面叶,表皮由一层紧密的形状不规则的表皮细胞组成,维管组织较发达,导管分布较多,上下表皮均分布有表皮毛,但以下表皮为主。     

Glycosides from Marine Sponges (Porifera, Demospongiae): Structures, Taxonomical Distribution, Biological Activities and Biological Roles

Literature data about glycosides from sponges (Porifera, Demospongiae) are reviewed. Structural diversity, biological activities, taxonomic distribution and biological functions of these natural products are discussed.     

水砂石破坏混凝土坝力学机理

从水砂石宏观力学和微观力学的作用效果出发,定性地探讨了水砂石破坏混凝土坝的力学机理,得出了混凝土力学性能变化的趋势,并在此基础上提供了一些展望与看法。     

Reducing Sediment Connectivity Through man‐Made and Natural Sediment Sinks in the Minizr Catchment,Northwest Ethiopia

Man‐made and natural sediment sinks provide a practical means for reducing downstream reservoir sedimentation by decreasing soil erosion and enhancing the rate of sedimentation within a catchment. The Minizr catchment (20 km²) in the northwest Ethiopian highlands contains numerous man‐made soil and water conservation (SWC) structures such as soil bunds (Erken), fanya juu ridge (Cab) and micro‐trenches and natural sediment sinks such as wetlands, floodplains and grassed waterways. These sediment sinks reduce downstream sedimentation into the Koga reservoir, located at the catchment outlet, however, a large quantity of sediment is still reaching the reservoir. This study evaluates the function and effectiveness of both man‐made SWC structures and natural sediment sinks in reducing sediment export from the Minizr catchment. SWC structures and natural sediment sinks were digitized using Google Earth Imagery. Sediment pins and vertical sampling through the deposit were used to quantify the amount of deposited sediment. In addition, inflow and outflow of suspended sediment data were used to calculate the sediment‐trapping efficacies (STE) of man‐made SWC structures (soil bunds and fanya juu ridges) and natural sediment sinks. Results reveal that 144 km soil bunds and fanya juu ridges trapped 7,920 Mg y⁻¹ (55 kg m⁻¹ y⁻¹) and micro‐trenches trapped 13·26 Mg y⁻¹, each micro‐trench on average trapped 23 kg y⁻¹. The 17 ha floodplain located in the centre of the catchment trapped 9,970 Mg y⁻¹ (59 kg m⁻² y⁻¹), while a wetland with a surface area of 24 ha, located near the outlet of the catchment, trapped 8,715 Mg y⁻¹ (36 kg m⁻² y⁻¹). The STEs of soil bunds and fanya juu ridges, wetlands and floodplains were 54%, 85% and 77%, respectively. Substantial differences were observed between the STE of grassed and un‐grassed waterways at 75% and 21%, respectively. Existing man‐made and natural sediment sinks played an important role in trapping sediment, with 38% (26,600 Mg y⁻¹) of transported sediment being trapped, while 62% (43,000 Mg y⁻¹) is exported from the catchment and thus enters the Koga reservoir. Therefore, additional catchment treatment measures are required as an integrated catchment scale sediment trapping approach to help reduce sediment loads entering Koga reservoir. Moreover, to maximize the effectiveness of sediment trapping measures, avoid structural failure and ensure their sustainability, regular maintenance is needed. Copyright © 2016 John Wiley & Sons, Ltd.     

湖南南岭地区毛栲群落结构及空间格局分析

通过对湖南南岭地区毛栲群落的样地调查,分别对野生毛栲群落的水平结构、垂直结构、种群龄级结构、空间分布格局及动态进行了研究分析。结果表明:湖南南岭地区毛栲群落空间分布格局为聚集分布,但由于人为破坏,其种群结构已日趋简单化,自我更新弱。最后,提出了毛栲资源保护与开发的建议。     

灵武长枣正常果与裂果解剖结构的比较研究

运用石蜡切片对灵武长枣正常果实与裂果的解剖结构进行了观察,探讨裂果发生的原因。结果表明:长枣正常果角质层厚度、亚表皮细胞层数与裂果相近;但正常果实表皮细胞层数较裂果多,表皮厚度也较裂果厚;中果皮细胞排列较裂果的紧密;中果皮细胞大小、维管束粗细及多少、空腔大小及多少与裂果的相近。