基于差异沉降最小的桩筏基础分布分析

利用桩筏基础分析方法,对层状地基上不同布桩方式的桩筏基础进行计算,给出无量纲化的计算结果,并分析与探讨了布桩方式对桩筏基础的平均的沉降,差异沉降,筏板的负荷承担比和筏板弯矩的影响特征。     

USING ENZYME TO IMPROVE THE QUALITY OF SECONDARY FIBER

INTRODUCTIONIn recent years, the secondary fibers have played more important role in paper industry, especially for China, which has less forest area than other countries. However the recycled fibers have lower freeness and strengths than virgin fibers, and the low pulp freeness limits the speed at which the paper machine can operate, lower strengths limits the use of recycled fibers in fine paper [1].Many techniques have been studied for these defects. Refining or beating tends to optimi…     

基于边界层模糊调节的液压系统准滑模变结构控制

提出一种基于边界层模糊调节的准滑模变结构控制方法.基于滑模开关函数及其变化量,设计一个二维边界层模糊调节器,根据滑模开关平面状态的变化动态调整滑模边界层的宽度.应用于液压位置系统的控制实验结果表明,所提出的控制方法能保证液压系统响应速度,提高控制精度,削弱抖振,较好地协调了变结构控制鲁棒性与平滑控制抖振之间的矛盾.     

正交法在绿化基材配比中的应用

基础设施建设导致大量裸露边坡的产生,为保护生态环境的需要我们必须对其进行生态防护,厚层基材喷射绿化技术则是满足这一需要的有效手段,而基材的配比又是该技术的中心问题。现以实验为基础,详细地介绍了正交法在实验结果分析中的应用,有效地解决了基材配比中的难题,对工程实践的指导具有较强的现实意义。     

Intragenic tandem repeats generate functional variability

Tandemly repeated DNA sequences are highly dynamic components of genomes. Most repeats are in intergenic regions, but some are in coding sequences or pseudogenes. In humans, expansion of intragenic triplet repeats is associated with various diseases, including Huntington chorea and fragile X syndrome. The persistence of intragenic repeats in genomes suggests that there is a compensating benefit. Here we show that in the genome of Saccharomyces cerevisiae, most genes containing intragenic repeats encode cell-wall proteins. The repeats trigger frequent recombination events in the gene or between the gene and a pseudogene, causing expansion and contraction in the gene size. This size variation creates quantitative alterations in phenotypes (e.g., adhesion, flocculation or biofilm formation). We propose that variation in intragenic repeat number provides the functional diversity of cell surface antigens that, in fungi and other pathogens, allows rapid adaptation to the environment and elusion of the host immune system.     

不同因素对泡囊水溶液中磷脂酶A2活性的影响

首次在泡囊水溶液中研究磷脂酶A2 催化水解卵磷脂并考察了各种因素对该反应的影响.研究结果表明:在泡囊水溶液中磷脂酶A水解卵磷脂的最佳温度为 50℃.     

CCN蛋白家族研究进展

CCN蛋白家族包含多个成员,它们结构相似,富含半胱氮酸。作为分泌蛋白,CCN蛋白能够促进细胞生长、细胞粘附、细胞迁移;诱导细胞凋亡;并调控肿瘤生长、血管发生和软骨内骨化。由于CCN蛋白在癌症和其它疾病预测或／和诊断中的重要性,成为近几年研究的热点。本文将简述近几年在CCN蛋白领域的研究进展。     

双权A_r~λ(Ω)弱逆Hlder不等式

推导A-调和方程d*A(x,dω)=0解的局部Arλ(Ω)双权弱逆Hlder不等式,其x∈Ω,a.e,对任意ξ∈Λl(Rn),算子A:Ω×Λl(Rn)→Λl(Rn)满足条件|A(x,)ξ|≤α|ξ|p-1和〈A(x,ξ)ξ〉≥|ξ|p,常数α满足0<α≤1,固定指数p满足1相似文献   

中国海岸带耐盐经济植物资源

我国海岸带耐盐经济植物种类十分丰富,约有１１５科３５９属５１７种具有经济潜力的耐盐植物,其中药用资源植物４３６种,芳香资源植物４６种,纤维资源植物８３种,油脂及树脂资源植物５０种,饲草资源植物１５２种,此外还有蜜源植物和观赏植物。作者对其进行了分类评述,并在此基础上提出一些开发利用的建议。     

车床主轴系统精度对超声振动车削的影响

文章分析了超声振动车削时工件的装夹偏心和车床主轴的旋转精度对加工表面粗糙度的影响。