元素硫对825合金在高温高压含CO2/H2S环境中腐蚀行为的影响

目的研究元素硫对825合金在高温高压含CO2/H2S环境中腐蚀行为的影响,为评价825合金在高温高压含CO2/H2S和元素硫环境中的适应性提供依据。方法将825合金分别置于含元素硫和不含元素硫的模拟气田环境中,进行高温高压含硫实验。采用失重法、高温高压电化学法、扫描电镜和能谱测试方法对825合金的均匀腐蚀、局部腐蚀、电化学腐蚀、微观形貌和化学组成进行表征,揭示元素硫对825合金在高温高压含H2S和CO2环境中腐蚀行为的影响规律。结果在不含元素硫的环境中,825合金的均匀腐蚀速率仅为0.0217 mm/a,无局部腐蚀现象产生,也没有检测到明显的点蚀噪声信号;在含元素硫的环境中,825合金的均匀腐蚀速率高达0.469 mm/a,具有明显的局部腐蚀特征,且点蚀噪声信号显著,与光学照片观察结果一致。结论825合金在高温高压含元素硫和氯离子环境中容易发生局部腐蚀,这主要是由于元素硫在水溶液中发生水解反应,在局部区域生成了H2S和H2SO4,在高温和氯离子的耦合作用下,显著地加剧了825合金的腐蚀,腐蚀产物以氧化物和硫化物为主。     

将“5S”作为实施ISO14000的辅助方法

简单介绍了“5S”管理,提出了将“5S”作为实施ISO14000的辅助方法,并在实施ISO14000的企业中推行“5S”管理的方法。     

石油集输系统中硫酸盐还原菌的分布和多样性

分别用亚甲蓝比色法、MPN法和16S rRNA基因序列分析方法,研究中国长庆油田(陕北)石油集输系统中原油和水样中H2 S的分布以及硫酸盐还原菌(SRB)的分布和多样性.结果表明,从油井井口经石油计量站再到石油综合处理站的集输系统中,原油中H2S的含量依次为105.80、99.70、24.57 mg.L-1;SRB的数量依次为98、300、680 CFU.100 mL-1.水样中H2S的含量依次为1.13、2.80、3.49 mg.L-1;SRB的数量依次为9 500、40 000、76 000 CFU.100 mL-1.集输系统中水样中SRB的数量平均为原油样品的100倍以上.原油井口中高浓度的H2S抑制了SRB的生长,SRB数量较少;随着H2S浓度的降低,抑制作用削弱并消失,使集输系统中SRB的数量逐渐增加.水样中H2S初始浓度较低,SRB数量较多,系统中H2S的含量随着SRB数量的增大而逐渐增多.由16S rRNA基因的序列分析表明,能够同时在水样和原油样本中检测到与脱硫弧菌属(Desulfovibrionaceae sp.)以及脱硫球菌属(Desulfococcus sp.)相关的SRB基因序列.但是,在水样中能够检测到与脱硫念球菌属(Desulfomonile sp.)、脱硫弯杆菌属(Desulfotomaculum sp.)和脱硫八叠球菌属(Desulfosarcina sp.)相关的SRB基因序列,而在原油样本中未检测到.在石油集输过程中由于环境条件的变化,水样和原油样品中SRB的多样性都有一定的增加.     

The metabolism of neonicotinoid insecticide thiamethoxam by soil enrichment cultures,and the bacterial diversity and plant growth‐promoting properties of the cultured isolates

A soil enrichment culture (SEC) rapidly degraded 96% of 200 mg L^?1 neonicotinoid insecticide thiamethoxam (TMX) in MSM broth within 30 d; therefore, its metabolic pathway of TMX, bacterial diversity and plant growth‐promoting rhizobacteria (PGPR) activities of the cultured isolates were studied. The SEC transformed TMX via the nitro reduction pathway to form nitrso, urea metabolites and via cleavage of the oxadiazine cycle to form a new metabolite, hydroxyl CLO‐tri. In addition, 16S rRNA gene‐denaturing gradient gel electrophoresis analysis revealed that uncultured rhizobacteria are predominant in the SEC broth and that 77.8% of the identified bacteria belonged to uncultured bacteria. A total of 31 cultured bacterial strains including six genera (Achromobacter, Agromyces, Ensifer, Mesorhizobium, Microbacterium and Pseudoxanthomonas) were isolated from the SEC broth. The 12 strains of Ensifer adhaerens have the ability to degrade TMX. All six selected bacteria showed PGPR activities. E. adhaerens TMX‐23 and Agromyces mediolanus TMX‐25 produced indole‐3‐acetic acid, whereas E. adhaerens TMX‐23 and Mesorhizobium alhagi TMX‐36 are N₂‐fixing bacteria. The six‐isolated microbes were tolerant to 200 mg L^?1 TMX, and the growth of E. adhaerens was significantly enhanced by TMX, whereas that of Achromobacter sp. TMX‐5 and Microbacterium sp.TMX‐6 were enhanced slightly. The present study will help to explain the fate of TMX in the environment and its microbial degradation mechanism, as well as to facilitate future investigations of the mechanism through which TMX enhances plant vigor.     

基于3S技术和AHP的贵阳市土地综合承载力研究

近年来，随着中国经济的快速发展，人地关系变得越来越紧张。主要讨论了贵阳市研究区的土地综合承载力状况，利用GIS和RS技术对研究区土地利用现状和地形地貌特点进行深入分析，建立“空间属性一体化”数据库。构建了一套适合区域土地承载力综合评价指标体系，并运用层次分析法确定各个指标权重，求算出贵阳市各个地区土地承载力综合评价分值，最后将贵阳市的土地承载力划分为3个类型区：一是低承载力区（Y〈0．2），有花溪区、清镇市、修文县、息烽县、开阳县；二是中等承载力区（0．2〈Y〈0．5）。属于这种类型区的有4个地区，主要包括乌当区、白云区；三是高承载力区（Y〉0．5），主要有南明区、云岩区和小河区。这3个类型区分别代表土地承载力演替从低层次的均衡发展阶段到较高层次的不均衡发展阶段再到高层次的系统协调均衡发展阶段。结果表明，贵阳市目前的土地资源处于紧张状态，但不同的地区又有所差异，表现出一定的空间地域性，最后对当地土地利用政策制定，提出了建议。     

Studies on the origin of the methylsulfonyl‐containing metabolites from propachlor

Abstract

Metabolites in which the chlorine from propachlor has been replaced by a cysteine group or a methylsulfonyl group [‐S(O₂) CH₃] are present in the urine of rats dosed orally with propachlor. In the present study, urine from rats given single oral doses of ³⁵S‐labeled cysteine conjugate of propachlor contained metabolites having the methylsulfonyl groups labeled with S. No metabolites containing ¹⁴C‐labeled methylsulfonyl groups were isolated from urine of rats given single oral doses of the cysteine conjugate of propachlor in which the cysteine group was uniformly labeled with ¹⁴C. These findings show that the cysteine conjugate of propachlor is the source of sulfur in the methylsulfonyl‐containing metabolites. Therefore, we suggest that a C‐S lyase present in the animal cleaves the cysteine conjugate of propachlor and thus allows further metabolism of the sulfur to a methylsulfonyl moiety.     

Effects of DDT and piperonyl butoxide on the metabolic alterations in pigeon (columba livia)

Abstract

Effect of acute doses of technical grade of dichloro diphenyl trichloro ethane (DDT) and piperonyl butoxide (PB) on hepatic micro‐somal cytochrome P₄₅₀ (Cyt. P450) and cytosolic glutathione‐S‐transferase (GST) activity in pigeon were studied after 24 hours of treatment. A completely reverse trend of changes in Cyt. P450 and GST activity were found as increase in Cyt. ?450 paralleled with decrease in GST activity following exposure to DDT. However, intensity of changes in Cyt. P450 was greater than that of GST. A dose dependent decrease in Cyt. ?450 and GST activity was observed after PB treatment. The study may, therefore, throw some light on metabolic alterations in wild birds resulting from environmental pollution by DDT and allied chemicals.     

Effects of herbicide stress on wheat cultivars from organic and conventional cropping systems

Abstract

Wheat (Triticum aestivum L.) seedlings grown from seeds produced in “organic”; (non‐chemical) and “conventional”; cropping systems are characterized by a) similar rates of root and shoot growth, b) equal sensitivity to phytotoxicity by the herbicide glyphosate, and c) equivalent basal activity of the enzyme glutathione S‐transferase (both in the roots and in the shoots). In addition, treatment of these seedlings with glyphosate leads to significantly higher contents of this enzyme both in the shoots and in the roots. However, time‐course and dose‐response investigations indicate significant differences in the induction pattern of glutathione S‐transferase: the response of “conventional”; wheat seedlings takes place earlier and with higher efficiency, than that of the “organic”; ones.     

络合铁法脱除垃圾填埋气中的H2S

建立了以EDTA和柠檬酸为铁盐络合剂的循环脱硫体系,采用络合铁法对垃圾填埋气中的H2S进行脱硫中试实验,结果表明实验所建立的络合铁脱硫体系运行稳定,脱硫效率高,适合应用于垃圾填埋气中硫化氢脱除。     

BAF处理生活污水过程中同步去除H2S的试验研究

采用曝气生物滤池处理生活污水的过程中,以混和臭气的空气为气源,以掺入了陶粒和铁炭颗粒的复合填料为载体,研究了反应器的运行条件和参数,结果表明,以混合臭气的空气作为气源对污水处理过程的需氧量基本无影响。当反应器的进气量为40 L/h,进水容积负荷和进气H2S的浓度分别在0.3～1.6 kg COD/(m³·d)和0.8～2.3 mg/m³之间变化时,可以实现出气和出水中H₂S和COD分别小于0.04 mg/m³和90 mg/L,满足同时达标排放的要求。H₂S的同步去除可能是通过微生物的氧化分解和形成FeS沉淀来实现的。