液相色谱-质谱法测定水中氨基甲酸酯类农药及其代谢物

建立了直接测定水中10种氨基甲酸酯类农药及其代谢物的超高效液相色谱-质谱分析方法。该方法对水样无需进行富集处理,水样过滤后就可以直接测定。实验结果表明:测定液中各氨基甲酸酯类农药及其代谢物的质量浓度与离子对峰面积在质量浓度0.5～1 000.0μg/L内具有良好的线性关系;方法检出限为0.1～5.0μg/L;加标回收率91%～103%;相对标准偏差为2%～5%。该方法具有简便快捷、灵敏度高的特点。     

偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附

以腈纶纤维为原料络合Fe3+制得偕胺肟合铁(Ⅲ)纤维,用其处理α-萘酚溶液,研究了偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附工艺条件和吸附动力学参数。实验结果表明,偕胺肟合铁(Ⅲ)纤维对α-萘酚的最佳吸附工艺条件为pH=3.0、吸附温度313.15K和吸附时间45min。在最佳工艺条件下,偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附在所研究的α-萘酚浓度范围内符合Freundlich等温吸附方程。未达到饱和吸附前,偕胺肟合铁(Ⅲ)纤维对α-萘酚的吸附符合一级反应动力学特征。     

钢筋混凝土梁裂缝宽度与裂缝深度的相关性试验研究

裂缝的出现极大地降低梁的使用寿命。裂缝宽度和裂缝深度作为裂缝的两个主要参数,目前对前者的研究相对成熟,而后者的研究甚少。通过对8根钢筋混凝土梁的静力加载试验,研究由荷载引起的结构裂缝宽度与深度的相关性发展形态,并考虑混凝土强度、保护层厚度和钢筋直径对裂缝特征的影响。结果表明:混凝土梁裂缝宽度的发展主要与钢筋配筋率有关;梁的开裂荷载与混凝土的劈裂抗拉强度有一定关系;裂缝宽度与深度的相关性大致呈三段式的发展,并拟合二者的曲线。     

一起直流单极连续3次闭锁故障仿真分析

宁夏电网目前已接入3回直流,其中第1回直流为±660 kV接入,容量为4 GW;第2回直流为±800 kV,容量为8 GW;第3回直流为±800 kV,容量为10 GW,并正式形成了送端直流群。随着特高压直流的接入,宁夏电网发生直流故障的次数逐渐增多。针对第2回直流某次典型单极连续3次闭锁故障,详细介绍了事故发生的过程和故障前后宁夏电网运行方式及系统动态特性的变化情况。利用PSASP程序建立宁夏电网仿真模型,还原了故障前电网运行方式,并仿真再现了故障后的电网动态过程。通过仿真与实测结果的对比,进一步明确了直流故障期间电网特性的变化情况,同时验证了仿真模型的准确性。     

Acoustic detection technology for gas pipeline leakage

Gas leakage from pipeline leads to significant environmental damages and industrial hazards, so small leakage detection for gas pipeline is essential to avoid these serious leakages. However, because of the high frequency component of leakage signal attenuates quickly, traditional detection method which inspects pressure or vibration signal has problem to get effective information from leakage signal. So, a novel detection method based on acoustic wave is proposed. This paper, firstly, researches on the phonation principle of pipeline leakage and the characteristic of sound source, and simulates the leakage acoustic field on the basis of aero acoustics. Secondly, using Wavelet Packet Transform method and Fuzzy Support Vector Machine pattern classification, the laboratory testing for identifying acoustic signal of gas pipeline leakage is presented. Finally, the field application demonstrates that the detection system could identify small gas leakage effectively and avoids false-alarms which caused by running conditions with a good prospect.     

电磁辐射职业危害及防护对策

科技飞速发展的今天,射频及微波技术已经广泛应用于国民经济的各个领域,这使得越来越多的从业人员在工作场所受到电磁辐射污染的影响。本文总结归纳了我国电磁辐射职业危害状况,分析了现代企业电磁辐射防护的新特点,并提出企业电磁辐射防护对策。     

北京市2006年9月至10月火灾简析

今年9至10月份,本市共发生火灾859起,死2人,伤7人,直接财产损失105万余元.与去年同比,除火灾死人持平外,其余三项指标均是下降的,其中火灾次数减少100起,下降10.4%,伤人减少5人,下降41.7%,直接财产损失减少27万元,下降20.5%.     

Effects of organic matter on Leymus chinensis germination,growth, and urease activity and available nitrogen in coastal saline soil

ABSTRACT

The present study was carried out to investigate the effect of three organic matters (stalk powder, microbial fertilizer, and manure) on Leymus chinensis germination, growth, and urease activity and available nitrogen (N) in coastal saline soil. The study was conducted in a completely randomized design with eight treatments: J₀V₀Y₀, J₁V₀Y₀, J₀V₁Y₀, J₀V₀Y₁, J₁V₁Y₀, J₁V₀Y₁, J₀V₁Y₁, J₁V₁Y₁. The notations were based on the quantities of each agent added to 1 kg of coastal saline soil: J₀ – no straw powder, J₁ – 0.2 kg straw powder, Y₀ – no manure, Y₁ – 0.3 kg manure, V₀ – no microbial fertilizer, V₁ – 0.2 L microbial fertilizer, each in quantic repeat. L. chinensis was sown as 50 seeds per pot. Results indicated that addition of organic agents exerted a significantly enhanced germination, increase in fresh weight and elevated soil urease activity. Soil available N levels were significantly positively correlated with soil urease activity and fresh weight, but not with germination rate. It is noteworthy that the halophyte L. chinensis showed improved characteristics when grown in coastal saline soil with addition of organic amendments.