塔式旋转混凝土布料机的工况计算及配重调控分析

塔式旋转混凝土布料机是一种可高效输送混凝土的工程机械,被广泛用于混凝土浇筑。施工过程中,为减小其布料端悬臂力矩、保证其塔架的稳定性,需要随时根据其伸缩桁架的伸缩量来调节其配重块的位置。运用有限元ANSYS软件,分析了布料机在极限工况条件下的结构强度和最大合力矩,计算了19种不同工况下力矩、桁架伸缩量及配重调节距离之间的数值关系。在此基础上,利用MATLAB的拟合优化功能得出三者之间的函数关系并绘制三维曲线。研究结果为塔式旋转混凝土布料机的安全运行提供数据支持,同时为其后续的优化设计提供参考。     

Squaring down of general MIMO systems to invertible uniform rank systems via pre- and/or post-compensators

Pre- and/or post-compensators are designed to square down a general MIMO system to a uniform rank system, the structure of which is almost similar to a SISO system. The method of squaring down either does not change the finite zero structure of the given MIMO system or simply adds additional finite zeros in the left half s-plane. The significance of such a squaring down lies in the simplicity of the structure of a uniform rank system lending itself for easy analysis and control design.     

Improving the performance of Invertible Bloom Lookup Tables

Invertible Bloom Lookup Tables (IBLTs) have been recently introduced as an extension of traditional Bloom filters. IBLTs store key-value pairs. Unlike traditional Bloom filters, IBLTs support both a lookup operation (given a key, return a value) and an operation that lists out all the key-value pairs stored. One issue with IBLTs is that there is a probability that a lookup operation will return “not found” for a key. In this paper, a technique to reduce this probability without affecting the storage requirement and only moderately increasing the search time is presented and evaluated. The results show that it can significantly reduce the probability of not returning a value that is actually stored in the IBLT. The overhead of the modified search procedure, compared to the standard IBLT search procedure, is small and has little impact on the average search time.     

混凝土构件的涂装保护

分析了自然环境对混凝土构件的影响，简述了混凝土构件涂装对防腐蚀涂料的要求及常规涂装保护措施。     

半刚性钢-混凝土组合节点受弯承载力的计算

在半刚性钢 -混凝土组合框架中 ,混凝土板中的纵向钢筋增加了节点的强度和刚度 ,但是 ,传统的设计方法往往忽略纵向钢筋的作用而采用简化的计算模型。因此 ,出于经济效益考虑 ,应该根据半刚性组合节点的实际受力性能建立更加准确的计算方法。这里详细介绍了考虑混凝土板纵向钢筋作用的半刚性组合节点受弯承载力的计算方法 ,计算结果表明 ,建议的公式与试验结果吻合良好 ,可供规范制定和工程应用参考。     

Gemini表面活性剂的结构特点及在采油中的应用

文章简要地介绍了Gemini表面活性剂的结构特点；从表面活性剂的作用原理出发，介绍了Gemini表面活性剂的优良性能：如表面张力、泡沫力、润湿力、优异的协同效应、耐温抗盐性等；在此基础上，阐述了该类表面活性剂在油田三次采油上的应用前景。     

Effect of the processing molding temperature on the crystalline structure and properties of acrylonitrile‐butadiene rubber/trinylon thermoplastic vulcanizates

The effect of the processing molding temperature on the properties and crystalline structure of acrylonitile‐butadiene rubber (NBR)/nylon 6,66,1010 (trinylon) thermoplastic vulcanizates (TPV) was studied. With decreasing molding temperature, the stress at 100% and elongation at break of TPV changed slightly, and the solvent resistance of TPV improved. The best conditions for processing molding were 170°C and 12 min. The crystalline structure of the nylon continuous phase in TPV was investigated by X‐ray diffraction, polarized optical microscopy, and differential scanning calorimetry. The results show that the crystalline structure of the nylon phase in TPV was more perfect/orderly and formed α‐crystalline structure at a processing molding temperature of 170°C. Therefore, the oil resistance of NBR/trinylon TPV clearly improved. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1374–1379, 2006     

Relationship of threshold diameter and Darcean permeability in unconsolidated porous structures

Experiment was conducted on the threshold pressure for atmospheric air through unconsolidated narrow size distributed mini sphere and sand particles at low flow rates. The threshold diameter calculated from measured threshold pressure showed that it does not follow the traditional similarity theory. This is consistent with our experiment on accurate permeability measurement, and can be explained as a result of gas slip flow within such micro pore structure. Our current work tend to find the method to predict the permeability-threshold pressure relationship for unconsolidated porous structures.     

Investigation of the effect of surface phosphate ester dispersant on viscosity by coarse-grain modeling of BaTiO slurry

To understand the role of phosphate ester dispersant, we investigated the rheology of a BaTiO slurry. For the model case, a coarse-grain molecular dynamics (CGMD) simulation was performed with the butyral polymer didodecyl hydrogen phosphate (DHP) in the toluene/ethanol solvent. By systematically analyzing the effect of DHP from an atomic-scale first principle and from all-atom MD to microscale CGMD simulation, we investigated how the adsorption of a DHP dispersant on a BaTiO surface affects the microstructure rheology of a BaTiO slurry. The first-principle and all-atom MD simulation suggests that DHP molecules prefer to locate near the BaTiO surface. CGMD simulation shows a reduction in viscosity with an increase in dispersants, suggesting that the dispersant population near the BaTiO surface plays a key role in controlling the rheology of the BaTiO slurry. In this study, we propose an approach for understanding the BaTiO slurry with molecular-level simulations, which would be a useful tool for efficient optimization of slurry preparation.     

Effect of the electrolyte composition on In and Ag–In alloy electrodeposition from cyanide electrolytes

A procedure for preparation of clear and stable indium cyanide electrolytes, containing indium salt, d(+)-Glucose and KCN is proposed. NMR investigations revealed that the formation of a complicated indium complex in which the products of the disintegration of d(+)-Glucose in the KCN-solution are closely situated to the indium ion ensures the clearness of the electrolyte. The effect of nitrate, chloride and sulphate ions on the electrochemical processes of indium and silver–indium alloy electrodeposition is studied by cyclic voltammetry. During alloy electrodeposition under galvanostatic conditions unique spatio–temporal structures are observed on the cathodic surface.