镇海乙烯裂解气阀组运行情况浅析

针对裂解气双闸板阀在国内乙烯厂应用的实例和出现的问题,介绍了镇海乙烯裂解气大阀在阀组设计、现场安装、管线施工、日常维护等方面所做的一些尝试。目前,12台裂解气阀组总体保持平稳运行超过24个月,尝试取得阶段性成果。     

大数据环境下云数据库安全防护方法研究

知识经济的时代,大数据独有的潜在价值正被逐渐发掘。然而,对数据安全的管控却面临着诸多挑战。依据现阶段云环境下数据库使用的发展状况和特点,探讨国网公司构建公共服务云、企业管理云和生产控制云(下称"三朵云")所面临的数据库安全风险。依照成熟的信息安全等级保护标准,对云环境下的数据库安全防护需求进行深入研究,提出云数据库安全的防护方法以及实施云数据库安全防护步骤,对推动云数据库安全起重要作用。     

The sticking behavior of an ultra purified ferritic stainless steel during hot strip rolling

During hot rolling of ferritic stainless steels (FSSs), sticking can cause severe surface defects both on work rolls and strips especially for ultra purified FSSs with the total amount of carbon and nitrogen being less than 150 ppm. In the present paper, high temperature oxidization behavior of the ultra purified FSSs was characterized. A new experimental method was invented to simulate the sticking behavior of ultra purified 21%Cr FSS, by which specially designed specimens were hot compressed with different processing parameters to simulate hot strip rolling process. The specimens were surface conditioned prior to the simulation test, either by mechanically polishing or by pre-oxidization to form oxide scales with certain thickness. Observation on the cross-section of sticky regions indicated that cracks had been formed by cyclic heating and cooling during hot deformation had been acting as nucleation sites for sticking particles. The results indicated that oxide scale could avoid the direct contact between roll surfaces and rolled materials to help reducing the sticking occurrence. The temperature region for easy sticking occurrence in the ultra purified 21%Cr FSS has been measured to be from 900 to 1100 °C, which is enlarged as compared to other plain FSSs. The tendency for sticking occurrence decreased with increasing strain rate and decreasing the hammer or work roll surface roughness.     

A framework for joint estimation of age,gender and ethnicity on a large database

Human age, gender and ethnicity are valuable demographic characteristics. They are also important soft biometric traits useful for human identification or verification. We present a framework that can estimate the three traits jointly. The joint estimation framework could deal with the mutual influence of age, gender, and ethnicity implicitly. Under this joint estimation framework, we explore different methods for simultaneous estimation of age, gender, and ethnicity. The canonical correlation analysis (CCA) based methods, and partial least squares (PLS) models are explored under our joint estimation framework. Both the linear and nonlinear methods are investigated to measure the performance. We also validate some extensions of these methods, such as the least squares formulations of the CCA methods. We found some consistent ranking of these methods under our joint estimation framework. More importantly, we found that the CCA based methods can derive an extremely low dimensionality in estimating age, gender and ethnicity. An analysis of this property is given based on the rank theory. The experiments are conducted on a very large database containing more than 55,000 face images.     

谈基础大体积混凝土施工裂缝控制

从养护、振捣方式、外部环境等方面对基础大体积混凝土出现裂缝的原因进行了分析,并对防止基础大体积混凝土裂缝的措施作了研究,主要包括削弱水泥水热化作用、严格施工管理、做好混凝土养护工作等,以期保证工程的施工质量。     

如何建立工程咨询企业的质量管理体系（提纲）

一、目的与要求 (一)目的:使咨询质量能满足顾客和相关方的需求和期望. 满足顾客(委托方)的要求.     

基于非参数核密度估计的扩展准蒙特卡洛随机潮流方法

扩展蒙特卡洛方法将随机潮流的误差转化为可控量,并可在样本数增加时保留已知的潮流计算结果。基于扩展拉丁超立方抽样的方法效率比简单随机抽样高,但仍存在两方面的问题:第一,扩展拉丁超立方抽样无法保证序列的差异性,这成为计算效率提高的瓶颈;第二,当输出变量偏离正态分布时,扩展拉丁超立方抽样方法缺乏性能良好的收敛判据。针对以上两个问题,采用基于Sobol序列的扩展准蒙特卡洛方法进行随机潮流计算,并提出基于非参数核密度估计方法的收敛判据。对IEEE 30和IEEE 118节点系统的仿真结果表明,所述方法比扩展拉丁超立方抽样方法更加方便、准确,同时效率更高、收敛更快;而基于非参数核密度估计的收敛判据直观、适应性强,对变量的概率分布没有附加条件,可准确指导扩展随机潮流的收敛。     

平朔东露天矿薄煤层开采方案

主要以平塑东露天矿在开采过程中出现的4#煤~9#煤之间夹杂的较为稳定的5#、8#薄煤层作为研究对象,综合考虑2个煤层上覆盖岩石及煤层厚度、走向、倾向、强度等因素,提出外包剥离、单斗-卡车、前装机-卡车、电铲、前装机-卡车联合开采4种开采方案;经过技术经济比较,证明推土机、电铲、前装机-卡车联合开采方案较适合东露天矿薄煤层开采。     

海洋用CRA双金属复合管管端全自动堆焊工艺改进

针对海洋用CRA双金属复合管薄壁基管堆焊过程中出现显著的管端缩径,机械加工后管端尺寸超差这一问题,设计了工艺革新及改进方案。通过采用优化焊接工艺参数和调整管端机械加工工艺等措施,使得双金属复合管管端机械加工后的尺寸满足了设计要求,同时Fe的稀释率降低。堆焊后对堆焊层进行拉伸试验、冲击试验、硬度测试、金相组织观察以及晶间腐蚀试验,结果表明,堆焊层的力学性能良好,且具备较好的耐腐蚀性能。