超高效液相色谱法测定土壤中微量阿特拉津

采用超高效液相色谱仪,建立了土壤中微量阿特拉津的快速检测方法.研究结果表明:采用反相C18色谱柱,以甲醇/水(70:30,v/v)为流动相,流速为0.2 ml/min,柱温为30℃,检测波长为220 nm条件下,在12.5～1000μg/L质量浓度范围内线性关系良好(r=0.9999),检出限0.18×10-3 mg/...     

A Screening Test for the Determination of Ethylene Sensitivity

Ethephon, which releases ethylene within plant tissues after application, was chosen to perform assessments of the relative sensitivity of crops to ethylene and to determine which stages of plant development were most sensitive. The species chosen were: barley, wheat, oats, canola and field pea, all of which are important crops in the province of Alberta, Canada. Plants were treated with ethephon at one of 7 different stages. Plants were assessed for their vegetative and reproductive growth, including height, biomass, yield and seed quality. Visual symptoms were photographed and documented to compare them with symptoms caused by ethylene applied as a gas. It was concluded that in barley, wheat and canola the late vegetative and early reproductive stages were most sensitive, at least when sensitivity was defined as reductions in yield and quality. As for field pea, ethephon had no effect on yield but did cause increased numbers of pods, which in certain conditions could lead to increased yields. Significant effects on vegetative growth were only observed in the early vegetative stages of development but with no effects on yield. The screening protocol successfully identified sensitive cultivars and growth stages for further investigation of the effects of ethylene exposure.     

氨制冷压力容器定期检验相关问题分析

随着大量制冷装置的建成和使用,氨制冷企业安全问题日益突出,定期检验作为保证在役氨制冷压力容器安全使用的一个重要环节,目前仍存检验依据不清、检验项目不明、检验针对性不足等问题.文中对氨制冷压力容器定期检验现状进行了介绍,对氨制冷压力容器损伤机理进行了分析和讨论,从损伤模式判别的角度提出了相应的检验策略,给相关人员提供一些...     

大气颗粒物致机体损伤的OH自由基机制

流行病学研究表明可吸入大气颗粒物浓度上升与人群呼吸道和心血管疾病发病率上升密切相关.毒理学实验和人体暴露研究显示可吸入大气颗粒物可导致机体广泛的损伤,但其致毒机制尚未明确.大量体内和体外研究表明了活性氧在颗粒物致毒过程中的重要作用,其中OH自由基具有极高的反应活性,是可吸入颗粒物致毒的重要机制.在总结国内外相关研究基础上,综述了OH自由基可能造成的大分子损伤、大气可吸入颗粒物暴露引发机体产生OH自由基的分子机制以及生物体系中OH自由基的检测手段,并对该领域的研究方向进行了展望.     

The dynamic changes of arsenic biotransformation and bioaccumulation in muscle of freshwater food fish crucian carp during chronic dietborne exposure

Dietary uptake is the major way that inorganic arsenic (iAs) enters into benthic fish; however, the metabolic process of dietborne iAs in fish muscle following chronic exposure remains unclear. This was a 40-day study on chronic dietborne iAs [arsenite (AsIII) and arsenate (AsV)] exposure in the benthic freshwater food fish, the crucian carp (Carassius auratus), which determined the temporal profiles of iAs metabolism and toxicokinetics during exposure. We found that an adaptive response occurred in the fish body after iAs dietary exposure, which was associated with decreased As accumulation and increased As transformation into a non-toxic As form (arsenobetaine). The bioavailability of dietary AsIII was lower than that of AsV, probably because AsIII has a lower ability to pass through fish tissues. Dietary AsV exhibited a high potential for transformation into AsIII species, which then accumulated in fish muscle. The largely produced AsIII considered more toxic at the earlier stage of AsV exposure should attract sufficient attention to human exposure assessment. Therefore, the pristine As species and exposure duration had significant effects on As bioaccumulation and biotransformation in fish. The behavior determined for dietborne arsenic in food fish is crucial for not only arsenic ecotoxicology but also food safety.     

环氧丙烷生产废液中1,2 -二氯丙烷的回收

介绍了从环氧丙烷生产废液中回收1,2-二氯丙烷的新方法。采用常压精馏、减压精馏、共沸精馏工艺分离环氧丙烷生产废液中的1,2-二氯丙烷。实验结果显示,共沸精馏工艺的效果最好;在含有一定量的共沸剂、釜温100℃、顶温86℃、回流比为1的条件下,塔顶馏分中1,2-二氯丙烷的质量分数可达到98％以上,1,2-二氯丙烷的回收率可达到97％以上。     

生物还原-化学沉淀法自烟气中的SO2制备ZnS

采用生物还原—化学沉淀法自烟气中的SO2制备ZnS,将含有Zn(OH)2杂质的粗品ZnS通过化学提纯制得高纯度ZnS。实验结果表明,采用NH4C l-NH3.H2O混合液对含有Zn(OH)2杂质的粗品ZnS进行提纯的优化条件为:每500m g粗品ZnS加入NH4C l与NH3.H2O摩尔比为1∶1、两组分浓度均为3.0m o l/L的10mLNH4C l-NH3.H2O混合液。X射线衍射分析表明,提纯后的产物粉末全部为ZnS,其纯度与ZnS标准试样相当。     

CO2资源化利用的现状及前景

介绍了CO2分离捕集最新工艺——电化学法、膜法、化学循环燃烧法的研究进展。评述分析了CO2的各种资源化应用前景：CO2气体用作生物碳源、辅助注射成型剂及有机物（如氨基甲酸酯、表面活性剂）合成原料等;液态CO2用于人造金刚石、热泵干燥、超临界CO2萃取及固体干冰冷喷射清洗等。CO2作为一种潜在的丰富碳源,应不断研发其新的应用领域,加快其工业化应用。     

负载稀土元素活性碳纤维在微型反应器中净化NO废气

以NH3为还原剂,以活性碳纤维（ACF）、HNO,浸渍的ACF、负载CuO的ACF和负载La2O3的ACF为催化剂,在微型反应器中考察各种催化剂对NO催化还原的活性,并进行了差热-热重、扫描电镜分析。实验结果表明,ACF负载La能有效地改善催化剂的活性,且催化活性中心为非晶态的氧化物;当ACF负载20％的La2O3时具有最好的低温活性,NO的去除率最高可达92％以上。     

基于FHWA的兰州市道路交通噪声预测模型的建立

结合美国道路交通噪声污染预测模型(FHWA)和国内学者在该方面的大量研究成果,选择兰州市主、次干道共计52条、142个监测点的建模采样数据,并应用统计学原理分析了影响道路交通噪声的各个因子与道路交通噪声的相关性,最终得出了符合兰州市道路交通特征的噪声污染统计预测模型.随后通过兰州市15个监测点的预测与实测对比验证后发现二者具有较高的一致性,此模型可应用在兰州市道路交通噪声污染的预测评价中.