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91.
现浇混凝土防渗渠道普遍采用设置伸缩缝的方法防止混凝土产生裂缝,而伸缩缝的止水易因老化和长草等遭受破坏,导致渠道渗漏。针对上述弊端提出了无伸缩缝混凝土防渗衬砌渠道的隔板跳仓浇筑施工技术。经过在多个大中型灌区节水项目中推广应用,总结出该施工技术的操作步骤和技术要点,包括基面处理措施,浇筑方法,操作要点,浇筑,振捣、抹面等的质量要求及适用范围。多年的运行实践表明,该技术可明显节约投资、缩短工期、延长使用寿命、有效改善防渗效果,且施工简便、工程质量易于保证等。 相似文献
92.
本文将单一水库预泄能力约束法,推广到梯级水库汛期水位动态控制中,并建立了梯级水库汛期水位联合运用和动态控制模型,假定预报信息准确,在不降低下游保护对象的防洪标准的前提下,最大限度发挥梯级水库的兴利效益。以苗家坝、碧口水库为对象进行了实时调度模拟,其结果相比于原设计汛限水位动态控制方案,减少了弃水,且保证最大出库流量均在可控范围内,达到在不降低防洪标准的前提下提高梯级水库兴利效益的目的,大大提高了洪水资源利用率。 相似文献
93.
This paper proposes a miniature bending joint composed of serial rolling joints; it refers to the classification of small joints of other products and studies on surgical applications according to the structures and transmissions. To achieve this, a pulleyless rolling joint is introduced as a unit component and the basic design principle is established for the joint. A simple mechanism guarantees a smooth rolling contact using elastic fixtures. Underactuation, which prevents S-shaped curvature similar to buckling, is applied to drive the bending joint with a limited number of wire cables. Using a 1-DOF real-sized prototype, experiments were performed to measure the motion accuracy and payload capacity from various angles to evaluate the efficacy of an improved design that enhances the payload on the distal end. This novel joint is applicable to a wider variety of surgical tools and catheters relative to other candidates owing to its small constant curvature, reasonable payload capacity, and miniature size. 相似文献
94.
为正确有效地分割出髋关节的外轮廓,提出了一种基于最佳分割线的股骨近端外轮廓的提取方法。该方法利用自底向上CT序列图像的帧间相似性找到一条分割目标股骨与其他骨骼的闭合分割线,从而利用该分割线来精确定位目标骨骼的位置,并搜索边缘点。实验结果表明,该方法能够准确地识别出股骨近端的外轮廓,自适应强,抗干扰性好。 相似文献
95.
The objective of this study was to determine how the fracture of adhesive joints depends on elastic beam parameters describing the adherends and the applied loads. The basic specimen geometry was the cracked lap shear joint constructed of aluminium alloy with various adherend and bondline thicknesses. Loads were applied in different combinations of bending, tension and shear to generate a failure envelope for each adhesive and specimen geometry. It was found that crack propagation for precracked specimens occured at a critical strain energy release rate but was also a function of the GI/GII ratio and the bondline thickness. The experiments also showed that the loads required to propagate a crack in a precracked specimen were always lower than the loads required to break the fillet. Hence, by treating uncracked joints as being cracked, where the fictitious crack tip is assumed to coincide with the location of the fillet, a conservative estimate of the failure load is obtained. 相似文献
96.
多菌灵、硫及三环唑混配成悬浮剂,对抑制稻瘟病菌的菌丝生长、分生孢子萌发、附着胞的形成、产孢能力及纹枯病菌菌丝生长等都具有较明显的协同增效作用,协同作用比率(SR)分别为1.64、5.58、4.30、1.81及1.73。混配剂集合了多菌灵、硫及三环唑的优点,并显示出耐雨水冲刷、持效期长的特点。田间试验亦表明其防病增产作用比较显著。 相似文献
97.
98.
在真空粉末绝热低温贮罐的制造过程中、通过吸附器分子筛的活化、夹层真空系统的处理和充装珠光砂等工艺方法的改进,可较大地缩短产品的制造周期并提高产品的质量。 相似文献
99.
Hiroyuki Sumi Akio Takemura Mikio Kajiyama Yasunori Hatano Bunichiro Tomita Hiroshi Mizumachi 《The Journal of Adhesion》1992,38(3):173-184
Power feed copolymers were synthesized using styrene and n-butyl acrylate through non-uniform feeding emulsion polymerization. Poly(vinyl alcohol) (PVA) was used as a protective colloid, onto which vinyl monomers were grafted. Power feed copolymer had a very broad glass transition temperature compared with random copolymer, even if grafting and/or crosslinking were introduced to the system. This tendency was almost the same as the non-grafted power feed copolymer where only low molecular weight surfactant was used.
Adhesive joint strengths of power feed copolymers were evaluated compared with random copolymers. In the case of usual linear power feed copolymer, the adhesive joint strengths were not higher than those of random copolymer, which was considered to be due to the lower film strengths of the power feed copolymer. Power feed copolymer having grafting showed slightly higher adhesive joint strengths over a wide range of temperatures than random copolymer. When crosslinking was introduced to the system, power feed copolymer showed much higher adhesive joint strengths over a wide temperature range. 相似文献
Adhesive joint strengths of power feed copolymers were evaluated compared with random copolymers. In the case of usual linear power feed copolymer, the adhesive joint strengths were not higher than those of random copolymer, which was considered to be due to the lower film strengths of the power feed copolymer. Power feed copolymer having grafting showed slightly higher adhesive joint strengths over a wide range of temperatures than random copolymer. When crosslinking was introduced to the system, power feed copolymer showed much higher adhesive joint strengths over a wide temperature range. 相似文献
100.
为强化上海市黄浦江供水系统的重要组成部分金泽水源地取水安全,又兼顾太湖流域及太浦河沿线区域防洪、供水需求,开展了太浦河太浦闸与沿线88个闸控口门的多目标联合调度研究。在分析太浦闸及两岸河道现有调度方式的基础上,拟定了两类共10个联合调度方案。采用细化后的太湖流域水量水质模型,对各调度方案进行了模拟。然后,构建了反映防洪、供水、水环境需求的多目标函数,采用蚁群优选算法对所有调度方案进行了优选。结果表明:与现状调度方案相比,太浦闸同时根据太湖水位和金泽断面水质情况加大下泄流量,同时太浦河沿线河道闸门有序控制,可显著提高金泽水源地关键水质指标达标率、抬升金泽水源地最低水位,又基本不影响流域及区域其他调度需求。 相似文献