自动紧链装置在刮板输送机上的应用

对两种自动紧链装置在刮板运输机的应用原理及效果作了说明,并从应用现场的实际情况指明了刮板运输机使用自动紧链装置的发展方向。     

A Coupled 3-D PNP/ECP Model for Ion Transport in Biological Ion Channels

The Poisson-Nernst-Planck (PNP) or Drift-Diffusion theory can be used to compute macroscopic current in ion channels in an efficient manner. The major drawback of the standard PNP theory is that it is based on a continuum model for the charge flow, therefore it models ions as a gas of point particles. Water is also not simulated explicitly, but introduced as a background medium with a given permittivity. The PNP model can be modified to include effects of finite ion size and water occupation by including a correction term, the Excess Chemical Potential (ECP), in the standard model. Gillespie et al. [1] developed a model for ECP correction, based on Density Functional theory, which is introduced in an existing 3-D PNP solver for ion transport in biological ion channels realized using the numerical computational platform PROPHET. Since incorporation of the ECP correction directly into the PNP matrix formulation is not an easy task, for demonstration purposes we developed a relatively simple decoupled relaxed iteration algorithm. Preliminary tests were conducted on idealized channel geometries, showing how the adopted ECP correction model alters significantly the ion densities inside the channel from those predicted by the conventional PNP theory alone.     

基于 ERP、ECP 的国网批次物资计划审查工作探析

基于ERP、ECP的物资计划审查工作是一项繁忙而又重要的工作,计划审查质量的高低,决定后续物资采购、合同签订、物资供应及结算各个环节的工作效率,同时对同业对标指标影响很大。文章针对国网总部批次物资计划审查过程中存在的各种因素进行分析总结,积极探讨解决方案,整理出一套行之有效的工作措施,并取得了较好的成效。     

Grain refinement of pure Al with different electric current pulse modes

A comparative study on grain refinement of pure Al by applying electric current pulse (ECP) at different positions in the mould was carried out. The experimental results showed that fine equiaxed grains were generated by exerting ECP at different electrode positions, and the highest proportion of fine equiaxed grain area was obtained when ECP was applied at the upper and lower lateral wall of the mould. The refinement mechanism of exerting ECP and the reasons of different refining efficiency with various ECP employing modes were also discussed.     

割缝管+ECP特殊固井完井技术在渤海的应用

渤海湾BZ26-2-2D井首次应用割缝尾管及管外封隔器技术成功地进行了特殊固井完井工艺。固井时采用2只封隔器,1号封隔器挤胀时用完井液;2号封隔器挤胀时用水泥浆,采用水泥浆挤胀封隔器还是首次应用。该技术的主要特点是:保护储层,作业安全,工具结构合理简单。为渤海地区开发潜山油藏提供了一个良好的完井方式,同时也摸索和总结出了一些宝贵的经验。     

Coupling of sequencing batch reactor and mesh filtration: operational parameters and wastewater treatment performance

Wastewater treatment performance of the combined process of sequencing batch reactor (SBR) and mesh filtration bio-reactor was investigated with a synthetic wastewater. In this system, the filtration was performed only by the water level difference between the reactor and the effluent port, with the help of a sludge layer which accumulated on the mesh filter.

A half volume of the mixed liquor was filtrated for ca. 1 h, and the filtration time was not affected by the initial pressure within the range of 0.5–2.0 m-H₂O. Since the mesh filter could effectively reject the biomasses in the reactor, the effluents contained SS of less than 1 mg/L and BOD of less than 10 mg/L under continuous or intermittent aeration conditions. Nitrogen was also removed effectively with the adjustment of aeration time under the intermittent aeration conditions.

The results obtained in this work indicate that mesh filtration could be effectively combined with SBR and improve the performance of SBR.

In addition, it was shown that the performance of the mesh filtration such as filtration time and solids separation was influenced significantly by the saccharide content in the exocellular polymer of the activated sludge.     

Effect of corrosion potential on the corrosion fatigue crack growth behaviour of low-alloy steels in high-temperature water

The low-frequency corrosion fatigue (CF) crack growth behaviour of different low-alloy reactor pressure vessel steels was characterized under simulated boiling water reactor conditions by cyclic fatigue tests with pre-cracked fracture mechanics specimens. The experiments were performed in the temperature range of 240-288 °C with different loading parameters at different electrochemical corrosion potentials (ECPs). Modern high-temperature water loops, on-line crack growth monitoring (DCPD) and fractographical analysis by SEM were used to quantify the cracking response. In this paper the effect of ECP on the CF crack growth behaviour is discussed and compared with the crack growth model of General Electric (GE). The ECP mainly affected the transition from fast (‘high-sulphur’) to slow (‘low-sulphur’) CF crack growth, which appeared as critical frequencies ν_crit = f(ΔK, R, ECP) and ΔK-thresholds ΔK_EAC = f(ν, R, ECP) in the cycle-based form and as a critical air fatigue crack growth rate da/dt_Air,crit in the time-domain form. The critical crack growth rates, frequencies, and ΔK_EAC-thresholds were shifted to lower values with increasing ECP. The CF crack growth rates of all materials were conservatively covered by the ‘high-sulphur’ CF line of the GE-model for all investigated temperatures and frequencies. Under most system conditions, the model seems to reasonably well predict the experimentally observed parameter trends. Only under highly oxidizing conditions (ECP ? 0 mV_SHE) and slow strain rates/low loading frequencies the GE-model does not conservatively cover the experimentally gathered crack growth rate data. Based on the GE-model and the observed cracking behaviour a simple time-domain superposition-model could be used to develop improved reference CF crack growth curves for codes.     

CDMA网中双VLR故障的捕捉与分析

双VLR是移动网用户在位置更新过程中会遇到的较严重的网络故障,对用户呼叫,特别是用户作被叫时有严重影响.本文从问题的发现、问题的捕获过程、分析和解决的全过程进行了详细的介绍.     

脉冲电流对钢液凝固过程中夹杂物迁移行为的影响

在钢液凝固过程中施加脉冲电流,通过观察和分析凝固试样中夹杂物的形貌、数量、尺寸和分布状态等,以研究施加脉冲电流对钢中夹杂物迁移行为的影响。结果表明,在脉冲电流的影响下,钢液凝固初期形成的晶核会发生脱落而形成结晶雨;在晶核下落过程中,钢中夹杂物也会随之向下部迁移。随着脉冲电流强度的逐渐增加,钢锭上、中部夹杂物逐渐减少,晶粒尺寸变小。在本试验条件下,当电流强度为56.6 A/cm2 时,钢锭上、中部夹杂物的总面积和总数量分别比未施加脉冲电流时的降低46.9% 和35.6%。对于夹杂物含量要求较高的钢种而言,在钢锭凝固过程中施加脉冲电流,控制结晶雨的形成和迁移过程不失为一种有效去除钢中夹杂物、提高钢锭质量的技术手段。     

装配式ECP复合墙体热工性能有限元分析

为探究装配式中空挤出成型纤维水泥（ECP）墙板的热工性能,以3种钢柱形式和5种墙体保温材料类型为参数,建立了15种ECP复合墙体的有限元模型,并根据模拟结果分析各参数对于ECP复合墙体热工性能的影响;同时在模型分析基础上模拟了钢柱热桥处采取外保温措施、外保温层厚度取0～50mm时的墙体内表面温度分布情况.结果表明：ECP复合墙体传热系数为0226～0319W/(m2·K),低于JGJ 26—2018《严寒和寒冷地区居住建筑节能设计标准》对于寒冷地区外墙传热系数的限值035W/(m2·K);对钢柱热桥部位采用外保温措施时,ECP复合墙体内表面温度升高,热桥影响范围减小,保温隔热性能显著提高.