西南地区覆冰气象要素的变化特征及综合评估

论文采用西南地区(95°~110°E,25°~35°N)96个常规气象观测站1961年1月1日至2009年12月31日逐日气象要素资料,应用模糊信息分配方法对西南地区形成覆冰的主要气象要素配置进行研究。以连续覆冰日数为主,建立了该地区满足气象条件的覆冰综合评估指数。结果表明,当同时满足地面日最低气温在-10~1 ℃,相对湿度≥80%,日照时数≤2 h这3个条件时,最易发生电线覆冰现象。我国西南地区的云南、贵州、四川三省交界处以及云贵高原大部为电线覆冰最为严重的地方,且覆冰灾害有非常显著的年际及年代际变化规律。     

硫酸盐废水生物处理产生的硫化物处理含Pb2+、Zn2+的钢丝酸洗废水

在一套小型搅拌反应器中,研究了碱沉淀(KOH,处理a)、碱沉淀及硫酸盐废水厌氧处理产生的硫化物出水混合(KOH+出水混合,处理b)、碱沉淀及N2吹脱硫酸盐废水厌氧处理产生的硫化物(KOH+N2吹脱,处理c),以及碱沉淀、硫酸盐废水厌氧处理产生的硫化物出水混合和N2吹脱硫化物联合(KOH+出水混合+N2吹脱,处理d)等4组处理方式对含Zn2+、Pb2+的钢丝绳酸洗废水处理效果的影响.废水pH值为0.7,Zn2+和Pb2+含量分别为450和3274 mg.L-1.结果表明,KOH+出水混合+N2吹脱的处理方式对废水有较好的处理效果,Zn2+和Pb2+的去除为氢氧化物、硫化物沉淀的共同作用结果,处理后,废水中Zn2+和Pb2+的去除率均达99.6%以上,满足污水综合排放标准(GB 8978—1996).     

A Pt-Bi bimetallic nanoparticle catalyst for direct electrooxidation of formic acid in fuel cells

Direct formic acid fuel cells are a promising portable power-generating device, and the development of efficient anodic catalysts is essential for such a fuel cell. In this work Pt-Bi nanoparticles supported on micro-fabricated gold wire array substrate were synthesized using an electrochemical deposition method for formic acid oxidation in fuel cells. The surface morphology and element components of the Pt-Bi/Au nanoparticles were characterized, and the catalytic activities of the three Pt-Bi/Au nanoparticle electrodes with different Pt/Bi ratios for formic acid oxidation were evaluated. It was found that Pt₄Bi₉₆/Au had a much higher catalytic activity than Pt₁₁Bi₈₉/Au and Pt₁₃Bi₈₇/Au, and Pt₄Bi₉₆/Au exhibited a current density of 2.7 mA·cm^-2, which was 27-times greater than that of Pt/Au. The electro-catalytic activity of the Pt-Bi/Au electrode for formic acid oxidation increased with the increasing Bi content, suggesting that it would be possible to achieve an efficient formic acid oxidation on the low Pt-loading. Therefore, the Pt-Bi/Au electrode offers a promising catalyst with a high activity for direct oxidation of formic acid in fuel cells.     

高强钢绞线网-聚合物砂浆加固钢筋混凝土板的抗爆性能数值分析

为研究高强钢绞线网-聚合物砂浆加固混凝土板的抗爆能力,用混凝土HJC动力本构模型,建立了混凝土板、炸药及考虑空气介质影响的流固耦合有限元计算模型。用动力分析软件ANSYS/LS-DYNA,对在爆炸荷载作用下加固前、后混凝土板的破坏形态和抗爆性能进行了数值分析。研究结果表明:混凝土板用高强钢绞线网-聚合物砂浆加固后,抗爆炸冲击能力明显提高。当小药量爆炸时,板顶、板底同时加固的效果明显优于板底单一加固;当药量较大时,板顶、板底同时加固的效果与板底单一加固相差不大。     

基于IPSO-BP神经网络的钢丝绳断丝损伤识别模型研究

为解决传统钢丝绳断丝损伤识别方法精度低，BP神经网络陷入局部最优等问题，提出改进粒子群算法（IPSO）的BP神经网络识别模型。通过采集钢丝绳断丝损伤信号，提取缺陷信号特征，用峰值、峰峰值、波宽、波形下面积和波动能量5个特征值组成特征向量作为神经网络的输人，断丝数量作为神经网络的输出；利用改进粒子群算法对BP神经网络的初始权值和阈值进行优化；建立基于IPSO-BP算法的神经网络模型，用于钢丝绳断丝的定量识别。结果表明:IPSO-BPS神经网络模型的钢丝绳断丝损伤识别精度、泛化能力均高于传统BP神经网络模型，且改进的粒子群算法迭代寻优速度更快。     

太湖流域源头南苕溪河口生态工程恢复及其初期水质净化效应

针对太湖流域源头溪流农业面源污染严重和生态拦截净化较弱的问题,采用生态工程措施于南苕溪人青山湖水库河口处对河道进行恢复.综合考虑山溪性河流水文水动力特征,通过构建、稳定和保护河口与滨岸带生态系统实现河道恢复目标.所采用关键技术包括:合金钢网石兜抛石技术、深潭-浅滩/塘-洼地组合净化技术、分流沙嘴技术、T-型乱石抛筑透水坝技术、河岸侵蚀面防侵蚀的浅滩沙洲场技术、植被缓冲带技术、水生植物恢复技术等.对河口生态工程区进行连续9个月的监测结果显示,工程区上段浅滩及分流沙嘴区能有效复氧,提升pH值并降低电导率,同时对总磷、活性磷和悬浮颗粒物有较好的去除效果;中段深潭区通过强化的微生物活性能有效去除铵态氮与亚硝态氮;下游T-型坝能较好地拦截并沉积河口冲刷物质,但需对其定期清理以防引发二次污染.河口生态工程运行初期较好地改善了河道结构并提升了河流自净能力,对河流生态恢复最具指示作用的水质指标溶解氧饱和度、铵态氮去除率在工程实施后较工程实施前平均分别提高了14.5％、14.7％.     

一种门窗五金件用冷轧窄带钢的轧制新工艺

详细介绍了一种用圆钢线材经处理 ,轧制、热处理、精轧成门窗五金件生产用圆盘窄带钢的新生产工艺和设备 ,以提高窄带钢轧制精度、表面质量 ,减少设备投资 ,同时介绍了国内外的应用情况。     

钨合金棒材无模流变成形有限元分析

采用刚塑性有限元法分析钨合金棒材无模流变成形变形区速度场、应力场及变形力。收敛条件采用总能量泛函收敛准则、速度收敛准则、节点力不平衡量收敛准则的 3个条件同时满足的收敛判定。给出钨合金棒材无模流变成形力能参数的数值解。变形力理论计算值与实验结果相吻合 ,相对误差小于 10 %。     

预应力锚索与锚杆在深基坑支护中的联合应用

结合现有的基坑土钉支护设计规范,通过合理分析计算,介绍了贵阳某综合楼基坑支护中预应力锚索锚杆联合支护方案。实践证明,在岩体破碎和地下水资源较丰富的条件下,该类型支护方案能取得较好的效果。     

Meta‐Analysis of the Effectiveness of Marked Wire in Reducing Avian Collisions with Power Lines

Abstract: Collisions of birds with power transmission and distribution lines have been documented for many species, and cause millions of casualties worldwide. Attempts to reduce mortality from such collisions include placing bird flight diverters (i.e., wire markers in the form of, e.g., spirals, swivels, plates, or spheres) on static and some electrified wires to increase their visibility. Although studies of the effectiveness of such devices have yielded contradictory results, the implementation of flight diverters is increasing rapidly. We reviewed the results of studies in which transmission or distribution wires were marked and conducted a meta‐analysis to examine the effectiveness of flight diverters in reducing bird mortality. We included in our meta‐analysis all studies in which researchers searched for carcasses of birds killed by a collision with wires. In those studies that also included data on flight frequency, we examined 8 covariates of effectiveness: source of data, study design, alternate design (if marked and unmarked spans were alternated in the same line), periodicity of searches for carcasses, width of the search transect, and number of species, lines, and stretches of wire searched. The presence of flight diverters was associated with a decrease in bird collisions. At unmarked lines, there were 0.21 deaths/1000 birds (n =339,830) that flew among lines or over lines. At marked lines, the mortality rate was 78% lower (n =1,060,746). Only the number of species studied had a significant influence on effect size; this was larger in studies that addressed more species. When comparing mortality at marked and unmarked lines, we recommend use of the same time intervals and habitats and standardizing the periodicity of carcass searches.