Purification and characterization of extracellular chitinase from a novel strain Aspergillus fumigatus CS-01

Twelve samples derived from different locations in south central area of China are treated by enrichment and spread-plate technique for initial screening. Seven chitinase-producing strains are isolated. The chitinase present in the culture supernatant of strain CS-01 possesses the maximum activity of 0.118 U/mL. Analysis of the morphological feature and the ITS rDNA sequence reveals that strain CS-01 belongs to Aspergillus fumigatus. Production of the chitinase is regulated by a inducible way and the maximum activity appears at 36 h in colloidal chitin culture. Purification of the chitinase is carried out by salting out, gel filtrate chromatography and anion exchange chromatography sequentially. Native-PAGE and SDS-PAGE indicate that the chitinase from A. fumigatus CS-01 is a monomer with the relative molecular mass estimated to be 4.50×10⁴. Its maximum activity appears at pH 5 and 55 °C. The chitinase is stable at pH 4.0–7.5 and below 45 °C. Foundation item: Projects(50621063, 50674101) supported by the National Natural Science Foundation of China     

±800kV直流输电线路硬跳线的三维可视化设计

基于线长恒定的原理,预置了跳线软体部分的弧垂,建立了硬跳线系统的状态方程。根据斜抛物线理论和三维空间技术,提出了跳线三维轨迹和电气距离的计算方法,工程计算实例验证了该解决方案的可行性和可靠性。     

输电线路新型节能导线的推广应用

结合国家电网公司基建新技术的推广应用,介绍了高导电率钢芯铝绞线、铝合金芯铝绞线和中强度全铝合金绞线的节能原理和性能,对比分析了3种新型节能导线在电气、机械特性等方面的技术差异,并对影响线路造价的敏感因素进行了分析,采用年费用和投资回收期法对导线的经济性进行了评价,最后提出了3种新型节能导线的工程应用范围,为节能导线的推广应用提供了参考。     

A new strain Leptospirillum ferriphilum YTW315 for bioleaching of metal sulfides ores

A new strain named YTW315 was isolated from Dexing area using the double-layer culture technique. The morphological, biochemical and physiological characteristics of YTW315 were studied. Physiological investigation indicates that the strain YTW315 is a strict (obligate) chemolithoautotroph, metabolizing ferrous iron and pyrite. The optimal growth conditions for the strain are 40 ℃ and pH 1.6. A phylogenetic analysis based on 16S rRNA sequences shows that the isolate is clustered to Leptospirillum ferriphilum with 99.8% similarity to Leptospirillum ferriphilum strain Fairview and ATCC 49881. The molar fraction of DNA (G+C) of the isolate is 58.1%. The strain can tolerate high concentration of Fe(Ⅲ) and As(V) (500 mmol/L and 50 mmol/L, respectively). Bioleaching experiment indicates that the strain can oxidize Fe(Ⅱ) efficiently, and after 30 d, 44.56% of copper and 95.31% of iron are extracted from chalcopyrite and pyrite, respectively.     

浅谈建设工程造价的确定与控制

建设工程造价的确定与控制是工程建设管理的重要组成部分,并贯穿于项目建设全过程。在工程造价管理的过程中,应加强控制目标的分阶段设置及以设计阶段为重点的建设全过程投资控制,同时应做到工程量的准确计量。     

10 kV纤维增强复合材料电杆结构设计

复合材料电杆具有轻质高强的特点,适用于复杂地形使用。以使用工况为依据,计算了水泥电杆的弯矩,构建了复合材料电杆的结构,采用有限元分析了其受力状态,结果表明,依此设计的电杆能够替代目前的水泥电杆,达到使用要求。     

三维建模在线路施工图设计中的应用

在输电线路工程的施工图设计中,提出了一种基于SLW软件接口的施工图三维地物建模技术路线,给出了道亨SLW文件的平面地物建模、输电设备解析的方法,并基于此开发了线路三维平台,最后结合滇西北至广东±800kV工程进行了实践应用。     

基于改进粒子群算法的进线档导线相间距离计算分析

为了校验并解决进线档最小相间距离的工程实际问题,建立进线档相导线的任意一点三维数学模型,通过改进粒子群算法,快速精确计算进线档相邻两相的最小相间距离。运用MATLAB程序仿真分析了相邻相的最小相间距离与档距、相导线张力、挂点高差的关系。仿真结果表明随着档距的增大,相邻两相的最小相间距离增加较快,随后增加趋势变缓;相邻两相的最小相间距离随着某一控制相的导线张力变大而减小;相邻两相的最小相间随挂点高差的增大而迅速减小。最后指出,敏感因素均有一临界值,超过该临界值,相邻两相的最小相间距离不满足合格距离要求。     

基于改进单纯形法的杆塔优化规划

输电线路的杆塔规划问题是一个由简单不等式约束的多维、非线性最优化问题,且不能保证其目标函数连续或可导,故传统的算法如穷举法、试凑法、解析法等求解均有较大局限性。为了解决上述问题,采用改进单纯形算法结合外点法罚函数求解此类问题,结果表明,算法辅以将约束条件作为指数罚函数的外点法构造增广目标函数,可以方便地处理各项约束条件的限制,计算效率高,鲁棒性强,程序实现简单。同时,文中采用的算法对于可能出现的局部最优解可以根据工程经验加以判别和剔除,适用性强。     

基于实测数据的海杂波特性分析

海杂波特性分析是进行海面目标检测算法优化设计和雷达性能预测的先决条件,文中对实测海杂波数据的统计特性和混沌特性进行了全面分析,进一步加深对海杂波的认识和了解。分析结果表明,所录取的数据符合K分布统计特性;根据现有的混沌特性判断准则,在一定程度上可以认为海杂波是具有混沌特性的,并利用Volterra滤波器构造一个非线性预测模型,验证了海杂渡是局部可预测的。