注聚区油井砾石分级充填防砂工艺技术研究

注聚区油井砾石分级充填防砂工艺技术是针对胜利油田注聚区见聚油井产出液黏度增大、携砂能力增强,提液引效措施加剧油井出砂使油井防砂有效期变短等问题进行研究的.该技术是在注聚区油井充填防砂时改变过去采用单一粒径砾石进行充填防砂的做法,将不同粒径砾石按不同比例分级充填到近井、炮眼附近和筛套环空,同时在中粒度粒径的砾石中加入经过...     

动力蓄电池包挤压失效仿真与实验

为提高动力蓄电池包挤压仿真的精度,将延性损伤准则引入到有限元仿真,通过单轴拉伸试验、纯剪切试验与缺口件拉伸试验与有限元仿真,获得了某动力蓄电池包结构所用材料6061-T6铝合金的延性损伤参数。型材三点弯曲试验、动力蓄电池包挤压试验与有限元仿真的结果表明：输入延性损伤参数的有限元仿真结果与试验结果误差小,能较为准确地模拟铝合金损伤对结构承载性能的影响;不考虑材料失效的结果与试验结果误差较大。     

无监督聚类在锂离子电池分类中的应用

单体电池的一致性,决定了电池组的性能,如何选出性能一致的单体电池又一直是电池组研究中的重点所在。本文采集了100个合格锂离子电池的6项性能指标(老化前后电压、容量、内阻、1C放电平台、电芯厚度),运用主成分分析(PCA)、核主成分分析(KPCA)、随机森林(RF)3种无监督聚类方法,对数据结构进行了研究。结果表明,数据指标之间存在复杂的非线性关系,主成分分析和核主成分分析,均未能形成明显聚类,但随机森林数据在低维空间显然形成4类,任意从中选4个电池组成电池组作循环性能仿真测试,结果显示由由该方法挑选出的单体电池具有较好的一致性。     

Research on heat dissipation performance and flow characteristics of air‐cooled battery pack

With the depletion of fossil fuels and the aggravation of environmental pollution, the research and development speed of electric vehicles has been accelerating, and the thermal management of battery pack has become increasingly important. This paper selects the electric vehicle battery pack with natural air cooling as the study subject, conducts simulation analysis of the heat dissipation performance of battery packs with and without vents. Then this paper researches on the influence of internal flow field and external flow field. Field synergy principle is used to analyze the effect of velocity field and temperature field amplitude. The results show the following: it is found that the maximum temperature rise and the internal maximum temperature difference of the battery pack with vents are reduced by about 23.1% and 19.9%, raising speed value can improve the heat dissipation performance, and raising temperature value can decrease the heat dissipation performance. Reasonable design of the vents can make the inner and outer flow field work synergistically to achieve the best cooling effect. Then the reference basis for the air cooling heat dissipation performance analysis of electric vehicle, battery pack structure arrangement, and air‐inlet and air‐outlet pattern choosing are offered.     

Freshness and quality attributes of cold stored Atlantic bonito (Sarda sarda) gravad

Quality and safety parameters of Atlantic bonito gravad during 42 days of storage at 7 ± 1 °C were analysed using monitoring sensory quality, microbial contamination, nucleotide degradation products, biogenic amines (BA), trimethylamine (TMA) and thiobarbituric acid reactive substances (TBARS). The shelf‐life of vacuum packed Atlantic bonito gravad was found to be 28 days. Total viable count (TVC) did not exceed 6 log CFU g^?1. Malonodialdehyde (MDA) content did not surpass 10 mg kg^?1. Nine biogenic amines were detected. Histamine level at the end of the storage was 355.3 mg kg^?1. TMA increased from 53.9 to 619.1 mg kg^?1. Among indicators based on the products of nucleotide degradation, the H value is best correlated with the sensory assessment. It can be concluded that the storage temperature of bonito gravad must be below 7 °C to prevent the threat to safety and quality posed by biogenic amines, especially histamine.     

热轧带钢卷及型钢全自动捆扎机的创新设计

在考察了国内现有热轧带钢卷与型钢生产线的捆扎现状以及研究了国内外多种钢材打捆机的基础上,研制了一种全新的带钢卷、型钢全自动捆扎机。详细介绍了该捆扎机的整体结构;系统阐述了该捆扎机主要组成部分以及性能原理。该捆扎机结构巧妙,易于操作和维护,能适应各种恶劣的工作环境。     

The bipolar plate of AISI 1045 steel with chromized coatings prepared by low-temperature pack cementation for proton exchange membrane fuel cell

The low-temperature pack chromization, a reforming pack cementation process, is employed to modify AISI 1045 steel for the application of bipolar plates in PEMFC. The process is conducted to yield a coating, containing major Cr-carbides and minor Cr-nitrides, on the substrate in view of enhancing the steel's corrosion resistance and lowering interfacial contact resistance between the bipolar plate and gas diffusion layer. Electrical discharge machining and rolling approach are used as the pretreatment to produce an activated surface on the steel before pack chromization process to reduce operating temperatures and increase deposition rates. The rolled-chromized steel shows the lowest corrosion current density, 3 × 10⁻⁸ A cm⁻², and the smallest interfacial contact resistance, 5.9 mΩ cm², at 140 N cm⁻² among all tested steels. This study clearly states the performance of 1045 carbon steel modified by activated and low-temperature pack chromization processes, which possess the potential to be bipolar plates in the application of PEMFC.     

矩形喷丝板组件设计

本文阐述了矩形喷丝板组件设计中较为关键的密封设计、导流板内腔设计及矩形喷丝板的刚度计算。     

防火墙技术的发展

随着Internet的迅速发展，网络越来越接近人们的生活，网络安全日益成为大家关注的问题，防火墙技术也越来越多地应用于网络中，文章对防火墙技术的发展作了全面介绍，并对几种防火墙技术作了比较。     

封隔高压一次充填防砂技术及其应用

管内外充填是当前砾石充填防砂技术的发展趋向,封隔高压一次充填正是这样的一种防砂技术。介绍了高压充填技术原理、工具结构及工作原理、施工程序,阐述了排量、压力等主要参数设计方法,介绍了在单层老井、多层大井段井、新井新层、斜井及粉细砂岩井的应用效果。该工艺施工简单,周期短,防砂有效期长,适应性强,采液强度高,便于后期处理,综合效益较高。