贺兰山东麓两次大暴雨天气过程对比分析

利用NCEP再分析资料和常规观测资料,对2006年7月13日和2012年7月29日2次发生在贺兰山东麓的大暴雨天气过程进行天气学分析,并对物理量场进行诊断分析,得出造成宁夏暴雨的主要影响系统有副热带高压、青藏高压、西风槽、西风急流.其中,副热带高压为暴雨提供充沛的水汽与能量,青藏高压提供了高空辐散场的维持机制和次级垂直环流的加强作用;700 hPa相对湿度≥80%为宁夏暴雨出现的必要条件,而相对湿度≥90%是大暴雨出现的必要条件;当暴雨发生时,暴雨区上空存在低空辐合高空辐散的垂直结构和次级环流;抬升指数LI均对强降水的预报有较好的指示意义.     

AZ91D镁合金铸锻双控成形组织性能研究

铸锻双控成形，是综合了压力铸造和锻造工艺特性而提出的一种新的成形方法。采用正交试验的方法进行AZ91D镁合金样件的试制，并对铸锻双控成形制件进行T6热处理，然后对样件进行力学性能测试及微观组织观察，得出在相同工艺参数条件下，铸锻双控成形制件比普通压铸件的抗拉强度和伸长率分别提高84．394％和101．761％；经热处理后则分别提高94．672％和121．617％；且微观组织晶粒细小。     

成都市水资源利用“木桶”效应的量化分析

为了从经济学角度,量化分析水资源对成都市经济发展的约束效应以及国民经济各部门的用水特性,借用“木桶”原理,运用经济学发展理论和投入产出技术,对成都市水资源的“矮板效应”、“高板效应”和“疏板效应”进行分类计算分析。结果表明：目前水资源还不是约束成都市经济发展的“瓶颈”资源,但在时间和空间上,其约束程度表现出一定的差异性;农业、餐饮业等部门浪费水资源较严重,用水量与城市化水平还未呈现合理的倒“U”形关系;水资源在各部门间配置还欠合理,在建筑业、文化娱乐和房地产业等配置较多,而对交通运输、工业和金融业等配置较少。     

Holistic and partial facial features fusion by binary particle swarm optimization

This paper proposes a novel binary particle swarm optimization (PSO) algorithm using artificial immune system (AIS) for face recognition. Inspired by face recognition ability in human visual system (HVS), this algorithm fuses the information of the holistic and partial facial features. The holistic facial features are extracted by using principal component analysis (PCA), while the partial facial features are extracted by non-negative matrix factorization with sparseness constraints (NMFs). Linear discriminant analysis (LDA) is then applied to enhance adaptability to illumination and expression. The proposed algorithm is used to select the fusion rules by minimizing the Bayesian error cost. The fusion rules are finally applied for face recognition. Experimental results using UMIST and ORL face databases show that the proposed fusion algorithm outperforms individual algorithm based on PCA or NMFs.     

数据库应用系统的建模研究

介绍了当今的软件建模发展现状及UML的建模框架和策略,并针对高校机房计费系统的实例,讲解与RUP相容的建模框架,给出了基于UML的数据库应用系统建模的整体设计流程。     

Detection of urinary biomarkers for early diagnosis of acute renal allograft rejection by proteomic analysis

Acute allograft rejection has been recognized as a major impediment to improved success in renal transplantation. Timely detection and control of rejection are very important for the improvement in long-term renal allograft survival. Thus, biomarkers for early diagnosis of acute rejection are required urgently to clinical medication. This study seeks to search for such biomarker candidates by comparing patients' pre-treatment urinary protein profiling with their post-treatment urinary protein profiling. A total of 15 significantly and consistently down-regulated protein candidates were identified. Among them, alpha-1-antichymotrypsin precursor (AACT), tumor rejection antigen gp96 (GP96) and Zn-Alpha-2-Glycoprotein (ZAG) were selected for further analysis. The results indicated that Western Blot assay of AACT, GP96 and ZAG had advanced the diagnosis time of acute renal rejection by 3 days, compared with current standard clinical observation and laboratory examination. Furthermore, the double-blind detection revealed that the accuracy, sensitivity and specificity of the diagnosis of acute renal rejection of AACT, GP96 and ZAG were 66.67%/100%/60%, 83.33%/100%/80% and 66.67%/100%/60%, respectively, and 100%/100%/100% in combination. In conclusion, urinary protein AACT, GP96 and ZAG could be a set of potential biomarkers for early non-invasive diagnosis of the acute rejection after renal transplantation.     

Solar-Driven Interfacial Evaporation Accelerated Electrocatalytic Water Splitting on 2D Perovskite Oxide/MXene Heterostructure

The rational design of economic and high-performance electrocatalytic water-splitting systems is of great significance for energy and environmental sustainability. Developing a sustainable energy conversion-assisted electrocatalytic process provides a promising novel approach to effectively boost its performance. Herein, a self-sustained water-splitting system originated from the heterostructure of perovskite oxide with 2D Ti₃C₂T_x MXene on Ni foam (La_1-xSr_xCoO₃/Ti₃C₂T_x MXene/Ni) that shows high activity for solar-powered water evaporation and simultaneous electrocatalytic water splitting is presented. The all-in-one interfacial electrocatalyst exhibits highly improved oxygen evolution reaction (OER) performance with a low overpotential of 279 mV at 10 mA cm⁻² and a small Tafel slope of 74.3 mV dec⁻¹, superior to previously reported perovskite oxide-based electrocatalysts. Density functional theory calculations reveal that the integration of La_0.9Sr_0.1CoO₃ with Ti₃C₂T_x MXene can lower the energy barrier for the electron transfer and decrease the OER overpotential, while COMSOL simulations unveil that interfacial solar evaporation could induce OH⁻ enrichment near the catalyst surfaces and enhance the convection flow above the catalysts to remove the generated gas, remarkably accelerating the kinetics of electrocatalytic water splitting.     

基于升参数的亚临界W火焰锅炉整体提效改造方案研究

对在役机组进行综合节能提效改造,有助于早日实现碳达峰。为提升燃用高硫无烟煤的亚临界300 MW等级W火焰锅炉机组能效水平,分析了主要影响因素和技术路线,对锅炉提升蒸汽参数、提高燃烧效率、降低排烟温度、机炉耦合等主要提效技术进行了可行性研究,形成整体改造方案,即升参数受热面改造+增设烟气暖风器+空气预热器漏风治理+磨煤机增容+风箱配风均匀性改造+燃烧系统局部适应性小改+增设低温省煤器。结果表明,针对设计参数为540 ℃/540 ℃的案例机组,升参数至574 ℃/572 ℃的整体提效方案可将机组供电煤耗降低25 g/(kW?h)以上。     

基于附加频变增益控制的风电-柔性直流输电系统次同步振荡抑制方法

针对风电-柔性直流输电系统动态相互作用引发的次同步振荡(SSO)问题,提出了一种基于附加频变增益(SFDG)控制的SSO抑制策略。基于阻抗理论揭示了风电-柔性直流输电系统SSO的发生机理;采用参数灵敏度分析从多个变流控制环节中优选出施加SFDG控制的最佳位置;将SFDG控制设计规范为多工况约束优化问题并求解实现其参数优化;通过对比施加SFDG控制前、后系统聚合阻抗的频率特性变化,从理论上说明SFDG控制的原理和作用。通过电磁暂态仿真验证了单一和2个SFDG控制的SSO抑制效果。     

基于分群结构优化的储能配置规划

储能资源与源网荷资源的深度融合是构建高比例可再生能源新型电力系统的关键,随着系统规划和运行环节源网荷储互动程度的不断提高,在储能资源规划过程中考虑其与源网荷资源的时空耦合特性已是储能规划的核心环节。构建储能选址分群结构优化模型,决策储能布点待选站点集合,并以储能投资净收益最大为目标,联合采用遗传算法和二阶锥松弛算法,求解含分群结构优化的储能配置优化规划模型。算例分析表明,面向大规模复杂网络的储能规划,考虑发用电特性及网架空间分布,分群优化布点储能,有利于协调不同送受特性的集群间储能资源的配置与协同增效运行,经济提高可再生能源消纳水平。