Prediction of reinforcement corrosion based on electrochemical equivalent under loading

Experiment was carried out to simulate different loading level elements under coupling of stray current and 5% chlorine salt solution. When calculating corrosion of reinforcement, the influence of loading should be considered based on the first law of Faraday electrolysis. The current density of the corrosion was measured by the linear polarization resistance method. The function of corrosion current density was obtained by nonlinear fitting method, and the influence coefficient of loading level to electrochemical equivalent was obtained base on the function of corrosion current density. The experimental results show that the corrosion current density increases with stress ratio of concrete structures. The reinforcement corrosion weight can be calculated through the influence coefficients of electrochemical equivalent and the result is in line with the actual situation.     

Clifford分析中三正则函数的线性边值问题

讨论Clifford分析中三正则函数的两类线性边值问题,运用积分方程的方法和压缩映射原理,得到了该问题A的解的积分表达式,并给出问题A'的另一种解法.     

Minimizing total weighted completion time with an unexpected machine unavailable interval

In the past two decades, scheduling with machine availability constraints has received considerable attention. Until recently most research has focused on the setting where all machine unavailability information is known at the beginning of the scheduling horizon. In reality, this is not practical in some cases. The machine may become unavailable to process jobs due to a machine breakdown or an occurrence of an emergent job that has to be processed immediately. In both cases, the start time of the unavailable interval is unknown beforehand, and the length of the interval may not be known until the end of the interval. In this article, we consider the situation in which the scheduler has to make scheduling decisions without any knowledge of the machine unavailable intervals. Of particular interest is the problem of minimizing total weighted completion time. When there are two or more unavailable intervals on a single machine, Fu et al. (2009) have shown that the problem is exponentially inapproximable even when jobs’ weights are equal to their processing times and one has full knowledge of unavailability. So in this paper we consider the scheduling problem on a single machine with a single unavailable period. And, we assume that every job has a weight proportional to its processing time. Based on whether the unavailable interval is due to a breakdown or an emergent job, we have the breakdown model and the emergent job model. First we show that no $\tfrac{\sqrt{5}+1}{2}$ -competitive online algorithm exists for the breakdown model, and no $\tfrac{11-\sqrt{2}}{7}$ -competitive online algorithm exists for the emergent job model. Next, we show that the simple LPT rule can give a 2- and a $\tfrac{9}{5}$ -competitive ratio for the breakdown model and the emergent job model, respectively. Further, we show that the ratios are tight by examples. For the offline case, we show that the First Fit LPT (FF-LPT) rule can give a tight approximation ratio of 2 and 4/3 for the breakdown model and the emergent job model, respectively. Finally, our experimental results show that, in practice, both LPT and FF-LPT perform very well and the performance improves when the number of jobs $n$ increases. In both models, when $n \ge 50$ , the worst case error ratio is much better than the theoretical bounds.     

Effect of cooling parameters on the microstructure and properties of Mobearing and Cr-bearing steels

To develop low-cost low carbon bainitic steel,Mo-bearing and Cr-bearing steels were melted in a vacuum induction furnace and were researched by thermal simulation and hot rolling at the laboratory.As the cooling rate increases from 0.2 to 50℃/s,the transformation temperatures of two steels lie between 650 and 400℃,and the final microstructures of them change from quasi-polygonal ferrite and granular bainite to lath bainite.Compared with cooling in air or by interrupted cooling,Mo-bearing and Cr-bearing steel plates cooled by sprayed water boast higher strength and superior toughness,for large-size islands are responsible for the poor mechanical properties.Compared to Mo,Cr is effective to isolate the bainitic reaction in low carbon steel,and the bainitic microstructure can also be obtained in Cr-bearing steel cooled at a wide range of cooling rate.     

基于Verilog HDL的逻辑分析仪电路设计

本文设计的是一个基于Verilog HDL的简易逻辑分析仪电路,在满足触发条件时,对被测信号进行采集、存储、并在示波器上显示所采集到的信号波形和时间标志线。在该逻辑分析仪电路中,所有信号都与时间相关,从而可以观察到时间的设置与保持、脉冲宽度、外部丢失的数据关系、也能够帮助我们实施数字硬件故障检测。     

多源数据融合技术在后备干部管理系统中的应用

随着社会信息化进程的逐步深入,各部门中已有业务系统在数据集成和信息共享方面存在不足,已达不到对信息资源整体开发利用的要求,这给后备干部信息管理工作带来了诸多不便.针对后备干部管理的业务特点和信息化的发展趋势,研发一个以数据集成和信息共享为目标的后备干部管理系统显得尤为重要.通过全面分析后备干部管理的业务需求和数据特点,提出了基于.NET平台和SQLite数据库的后备干部管理系统的设计方案,并以河南省为应用实例,验证了该系统设计方案的合理性和有效性.     

Rapid,simple and low cost fabrication of a microfluidic direct methanol fuel cell based on polydimethylsiloxane

In this paper a simple and rapid fabrication method for a microfluidic direct methanol fuel cell using polydimethylsiloxane (PDMS) as substrate is demonstrated. A gold layer on PDMS substrate as seed layer was obtained by chemical plating instead of conventional metal evaporation or sputtering. The morphology of the gold layer can be controlled by adjusting the ratio of curing agent to the PDMS monomer. The chemical properties of the gold films were examined. Then catalyst nanoparticles were grown on the films either by cyclic voltammetry or electrophoretic deposition. The microfluidic fuel cell was assembled by simple oxygen plasma bonding between two PDMS substrates. The cell operated at room temperature with a maximum power density around 6.28 mW cm^?2. Such a fuel cell is low-cost and easy to construct, and is convenient to be integrated with other devices because of the viscosity of the PDMS. This work will facilitate the development of miniature on-chip power sources for portable electronic devices.     

Electrosynthesis of Polyaniline/SiO2 Composite at high pH in the Absence of Extra Supporting Electrolyte

Summary Electropolymerization of aniline was investigated in solutions of different pH from 1.0 to 12.1 without extra supporting electrolyte. FT-IR Spectra of the polymers display characteristic absorptions for polyaniline (PANI) including that for protonated PANI, although some of the polymers were obtained in solutions of high pH. PANI obtained from acidic solutions displayed the usual electroactivities in 0.5 mol·l^-1 H₂SO₄, while those obtained from solutions of pH 6.0 to 12.1 showed an unusual redox pair additionally on cyclic voltammograms at 0.04 V vs. SCE. This redox pair can be ascribed to the redox of phenazine ring, originated from the attack of nitrenium cation to PANI chain in the ortho-position. Electrocodeposition of PANI and SiO₂ was conducted through electrophoresis of silica particles towards anode as aniline anodically electropolymerized. Energy dispersive X-ray diffraction (EDX) analysis and SEM inspection were performed on obtained PANI/SiO₂ to investigate the composite film.     

Enhancement of wetting properties of water-insoluble surfactantsvia solubilization

Water-insoluble surfactants generally show poor wetting behavior in the Draves skein wetting test. This does not appear to be due to high equilibrium or dynamic surface tension values, but to the presence of insoluble surfactant in the system. The replacement of a small percentage of the insoluble surfactant by a water-soluble one capable of solubilizing the former can produce a dramatic improvement in wetting behavior, even when the equilibrium or dynamic surface tension of the system is not significantly changed. Increase in the strength of the attractive interaction between the two surfactants generally improves the clarity of the system and decreases its wetting time.     

Some synergistic properties of N- Alkyl- 2- pyrrolidones,a New class of surfactants 1

N-Alkylpyrrolidones, a new class of commercial surfactants, interact synergistically with anionic surfactants. Mixtures of the N-2-ethylhexyl-(C2,6P), N-octyl-(C8P), N-decyl-(ClOP), and N-dodecyl-(C12P) pyrrolidones with commercial linear sodium alkylbenzenesulfonate (LAS) were investigated. Measurements of the molecular interaction parameters,β ^a, and β^M, for mixed monolayer formation and mixed micelle formation, respectively, in these mixtures indicated that the first three compounds show synergism in surface tension reduction efficiency and all four compounds show synergism in surface tension reduction effectiveness, when mixed in the proper proportions with LAS. This was confirmed experimentally. The N-alkylpyrrolidone-LAS mixtures also exhibit synergism in Ross-Miles foaming and in Draves (skein) wetting. Presented at the 70th annual meeting of the American Oil Chemists’ Society, Phoenix, Arizona, May 9, 1988. JAOCS, Vol. 66, no. 7 (July 1989)