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121.
通过对河道一级阶地粗砂层局部软弱地基进行换填处理的工程实例的分析,总结了换填处理对该地层的经济实用性,拓宽了换填处理及天然地基的应用范围,克服了该类场地桩基施工的难点,节省了工期和造价.同时积累了级配砂石换填处理的施工经验. 相似文献
122.
VINOGRADOVIgor 《科学通报(英文版)》2011,(Z2):3079-3081
Sliding plasma actuators were used to control the flow-induced broadband noise radiating from a bluff body. The structure consisted of a cylinder and a torque link that was installed on the lee side of the cylinder. The objective was to reduce the noise generated during the cylinder wake impinging on the torque link. By manipulating cylinder wake with the externally-imposed body force generated by the plasma actuators, the flow-structure interaction was reduced, leading to an attenuation of the broadband noise up to 3 dB in overall sound pressure level at a free stream speed of 30 m/s. 相似文献
123.
三线摆是研究转动惯量平行轴定理的重要仪器之一。在测量中使用传统方法用三线摆测量物体转动惯量时误差往往过大。而用补充法将两物体分别置于三线摆下摆盘的上下,使两物体的整体重心在下摆盘上,从而大大降低误差。 相似文献
124.
郑宇 《科技情报开发与经济》2009,19(7)
介绍了西门子DCS系统软件的特征,阐述了西门子DCS系统软件PCS7在现代大型焦--7.63 m焦炉控制系统中的应用. 相似文献
125.
女性紧身裤结构参数与样板优化设计的探讨 总被引:1,自引:0,他引:1
通过分析女下肢体特征及下肢体工学,指出常见紧身裤结构设计中,臀围松量、臀围与腰围前后差处理以及备细部结构数据的不合理性.探讨紧身裤的结构与样板优化设计,使紧身裤既能体现人体的曲线美,又不影响人们的活动与健康,并能与女下肢体达到吻合,符合下肢体运动功能,从而得到合理的、科学的紧身裤结构样板,为女紧身裤结构样板设计提供参考. 相似文献
126.
The hydrogen bonding pattern in complexes of the type [M2+(H2O)6](dmax)2 (M = Mn, Ni, Co, Zn, Cd, Hdmax = 1,3-dimethyl-8-azaxanthine), [M2+(H2O)4(py)2](dmax)2 (M = Mn, Co, Zn, Cd, py = pyridine) and [M2+(dmax)2(H2O)2(py)2]·2H2O (M = Ni, Cu) were studied by ab initio (MP2/LANL2DZ//B3LYP/LANL2DZ) and density functional theory methods (B3LYP/LANL2DZ, B3LYP/6-31G∗∗ and B3PW91/6-31G∗∗). The investigation includes a variety of theoretical analyses, which include interaction energy, many body analyses, electron density analysis, topological analysis, Mulliken atomic charges, natural atomic charges and harmonic vibrational analysis. The geometrical parameters and vibrational frequencies of dmax (the mono anion of 1,3-dimethyl-8-azaxanthine), [M2+(H2O)6] (M = Mn, Ni, Co, Zn, Cd), [M2+(H2O)4·(py)2] (M = Mn, Co, Zn, Cd) and the complexes, calculated by the theoretical methods, were compared with the recent X-ray crystallographic results and it was observed that the results are found to agree well with the crystallographic results. The present calculations provide an important physicochemical insight into metal cations with 1,3-dimethyl-8-azaxanthine. The results also reveal the active role of coordinated water molecules in modulating the binding of the cation through a specific network of hydrogen bonds. The topology of the motifs generated by these hydrogen bonds has been characterized, adapting to the second coordination sphere concepts usually applied to the first (monodentate, chelate, and bridge) coordination sphere. The optimized structures of the Cd2+, Zn2+ and Cu2+ complexes further interact among themselves in a less tight fashion to generate three dimensional structures (a tape-like hydrogen bond network). Finally these tape-like hydrogen bond network were optimized using the B3LYP/LANL2DZ basis set. 相似文献
127.
给排水工程中,对埋深较大而横截面尺寸相对不大的构筑物,采用大开槽施工将会造成占地面积大、土方量多等弊病,有时还受到施工场地限制。为此,常采用沉井法施工。沉井法适用于高地下水位、土质松软、流砂地段以及现场狭窄地段修建深埋构筑物。本文中沉井体积大,故采取先开挖再采用砂垫层很上铺承垫木扩大刃脚的施工技术。 相似文献
128.
Yongqing Li Jiuchuang Yuan Maodu Chen Fengcai Ma Mengtao Sun 《Journal of computational chemistry》2013,34(19):1686-1696
An accurate single‐sheeted double many‐body expansion potential energy surface is reported for the title system. A switching function formalism has been used to warrant the correct behavior at the and dissociation channels involving nitrogen in the ground and first excited states. The topographical features of the novel global potential energy surface are examined in detail, and found to be in good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. The novel surface can be using to treat well the Renner–Teller degeneracy of the and states of . Such a work can both be recommended for dynamics studies of the reaction and as building blocks for constructing the double many‐body expansion potential energy surface of larger nitrogen/hydrogen‐containing systems. In turn, a test theoretical study of the reaction has been carried out with the method of quantum wave packet on the new potential energy surface. Reaction probabilities, integral cross sections, and differential cross sections have been calculated. Threshold exists because of the energy barrier (68.5 meV) along the minimum energy path. On the curve of reaction probability for total angular momentum J = 0, there are two sharp peaks just above threshold. The value of integral cross section increases quickly from zero to maximum with the increase of collision energy, and then stays stable with small oscillations. The differential cross section result shows that the reaction is a typical forward and backward scatter in agreement with experimental measurement result. © 2013 Wiley Periodicals, Inc. 相似文献
129.
砂尘浓度指标严重影响砂尘风洞试验效果;在大型砂尘风洞中准确的测量及有效的控制砂尘浓度是砂尘风洞设备研制中的两个关键问题;针对动态试验工况环境中浓度传感器标定的问题,分析了浓度测量时标定参数与风速和浓度的关系,使用模型树算法建立了三者之间的关系模型,以此模型来预测各种动态情况下的标定参数;针对复杂环境下浓度动态控制问题,采用专家PID算法,提出了多回路控制系统结构和专家规则;工程实践表明该测量和控制方法满足了动态试验环境的需求,取得了良好效果;模型树算法和专家PID系统能有效的解决动态工况下砂尘浓度的测量与控制问题。 相似文献
130.
Classical problems in integral geometry and geometric probability involve the kinematic measure of congruent segments of fixed length within a convex body in R3. We give this measure from rotational formulae; that is, from isotropic plane sections through a fixed point. From this result we also obtain a new rotational formula for the volume of a convex body; which is proved to be equivalent to the wedge formula for the volume. 相似文献