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181.
针对普通方箍柱,井字式复合配箍柱和内埋工字钢柱铰在低周反复荷载作用下的实测滞回特性,提出了相应的动力分析了恢复力模型,并编制了地震作用下的弹塑性动力分析程序,采用ELCentro波和两种人工波,对3种框架柱铰进行了不同地震量级作用下动力反应耗过程计算分析,结果表明,安字式复合配箍柱和内埋工钢柱具有良好的抗震性能。 相似文献
182.
预应力高强混凝土桁架转换层结构的试验研究 总被引:3,自引:0,他引:3
结合南京新世纪广场工程,进行了一榀预应力高强混凝土桁架转换层结构在低周反复荷载下的试验,对预应力高强混凝土桁架转换层结构的变形能力、延性系数等抗震性能及其破坏机制作了研究.提出了有关此类转换层结构的设计建议 相似文献
183.
活性粉末混凝土(RPC)在热养护条件下几乎没有收缩,并且在长期荷载作用下的徐变也很小,本文探讨了RPC在大跨梁式桥中应用的可能性.以主梁的应力和结构的刚度为控制目标,拟定了一座主跨为200 m的RPC连续刚构桥,通过与同跨度预应力普通混凝土刚构桥的比较,讨论了不同主梁材料对大跨度连续刚构桥静力性能、稳定性及抗震性能的影响.分析结果表明:由于RPC具有较高的韧性及强度,在不降低结构正常使用性能的前提下,RPC主梁比普通混凝土主梁减轻自重达53%,其主梁截面的几何尺寸往往是由结构的刚度而不是强度控制;同时更轻的结构自重降低了惯性荷载,从而改善了整个结构特别是桥墩的抗震性能;并且桥梁上部结构自重的减轻提高了结构抵抗使用荷载的有效性,增大了桥梁结构的跨径. 相似文献
184.
李秉团 《华中科技大学学报(自然科学版)》1989,(4)
本文通过引入一个积分方程,给出了方程y″(x)+P(x)y(x)=f(x)存在振动解与非振动解的充分条件;并给出了使该方程最多只有一个非振动解的条件。 相似文献
185.
A series of dodecenylsuccinylated starches( DSSs) with different degree of substitution( DS) were prepared via the esterification of dodencenylsuccinic anhydride with hydrolyzed cornstarch in aqueous dispersion for investigating the influences of starch dodecenylsuccinylation upon the performances such as apparent viscosity and surface tension of starch paste, film behaviors,and adhesion to fibers for warp sizing. It was found that the dodecenylsuccinylation was able to reduce the surface tension of cooked starch paste and enhance the adhesion of starch to polyester fibers. It was also capable of depressing the brittleness of native starch and improving the mechanical behaviours such as breaking elongation and work-to-break of starch film. Initial increase in DS level of dodecenylsuccinylation enhanced these positive effects,while excessively increasing the level resulted in marked reduction in tensile strength of starch film and significant decrement in reaction efficiency. X-ray diffraction patterns of starch films showed the dodecenylsuccinates derivatized onto the backbones of starch depressed the degree of crystallinity of starch film. Based on the paste behaviors, adhesion, and film properties, the dodecenylsuccinylation level is recommended in a range of 0. 015-0. 025 for sizing polyester warps. 相似文献
186.
Tatiane Archanjo de Sales Erik Daemon Juliane Floriano Santos Lopes 《Journal of Natural History》2016,50(15-16):971-974
This study aimed to identify the feeding habit of Pheidole radoszkowskii Mayr on Rattus norvegicus (Berkenhout) carcasses, as well as whether its presence limits the occurrence of flies. Pheidole radoszkowskii exhibited more necrophagous than predatory behaviour. Its abundance was inversely proportional to that of flies, confirming that this ant species may cause lesions in carcasses and its presence limits the occurrence of flies. This work clarifies the behaviour of an ant species often encountered on carcasses. 相似文献
187.
Summary The role of host plants in the synthesis and release of lepidopteran sex pheromones is examined. Females synthesise pheromones de novo and pheromone quality is not markedly influenced by larval food sources. However, host plants may have a significant effect on different physiological and behavioural parameters associated with pheromone production. Males in some species of Nymphalidae and Arctiidae use secondary plant compounds, such as pyrrolizidine alkaloids, as a pheromone precursor. In such cases these plant compounds serve an additional role, such as protection against predation, and may reflect potential male reproductive investment. In the one instance where the effect of larval host plants on the de novo synthesis of a male sex pheromone was examined, larval nutrition did not alter either the quality or quantity of the hairpencil contents. 相似文献
188.
谭学才 《湖北民族学院学报(自然科学版)》2000,18(1):51-52
在 0 .2mol/LNH3 -NH4 Cl( 1∶1 ,pH9.3 0 )溶液中 ,托美汀 (TOL)在单扫示波极谱议上有一灵敏的导数极谱波 ,峰电位Ep=-1 .4 7V(vs.SCE) ,峰电流ip 与TOL的浓渡在 3 .5×1 0 -6~ 7.0× 1 0 -8mol/L范围内呈线性关系 ,检测限可达 8.0× 1 0 -9mol/L。该法用于片剂中TOL含量的测定 ,结果良好。对TOL在汞电极上的电化学行为进行了研究 ,实验结果表明 ,体系属不可逆吸附波。 相似文献
189.
房地产投资系统动力学模型的建立及其长期演化行为研究 总被引:12,自引:1,他引:11
借助于经济增长理论及计量经济学知识,首先构建了一个能够描述房地产投资系统运行规律的动力学模型。然后基于非线性理论,以计算机模拟为基本手段,对房地产投资模型的长期演化行为进行了深入研究,并得出了关于房地产投资系统的几点结论及一些需要注意的问题。最后分析了房地产投资系统出现混沌现象的动因。 相似文献
190.
Wool top and knitted fabric were treated with ammonia in the presence of sodium chloride (salt-ammonia process). The effectiveness of salt-ammonia process traditionally used as pretreatment for low temperature dyeing has been investigated for conferring shrink-resistance of wool. The pretreatmont of salt-ammonia process followed by enzymatic treatment has been proved that contribute to not only the enhancement of dyeing behavionr but also shrinkage-resistance in the present studies. A novel composition of salt-ammonia pretreatment, oxidized and reduced treatment as well as protease modification was recommended to achieve low temperature dyeing and shrinkage-resistance of wool. At the same time, the process conditions were optimized by orthogonal array and assessed by dye uptake rate, weight loss and area shrinkage. Laboratory experiments showed that the knitted fabric treated according to optimized conditions of the combined process, achieved not only improvement of dye abilities but also the strict requirement of machine-washable, representing a possible alternative to chlorination. 相似文献