聚苯硫醚新型滤料的特点及应用

介绍并分析了聚苯硫醚新型滤料的生产工艺及产品性能特点,提出了聚苯硫醚新型滤料在袋式除尘行业中的应用前景。     

入世前后中国农业贸易引致的就业“创造与替代”

我国加入世贸组织后,除了粮食安全、比较优势、竞争力等方面的影响研究外,农产品贸易开放对我国农业生产部门就业的影响一直令人关注,是具有比较优势的劳动密集型农产品出口带来更多就业创造,还是土地密集型农产品进口引致更多就业替代?本文运用1994-2009年数据,对入世前后农产品贸易开放引致的农业就业效应进行全面系统的实证分析,并对在不同情形下我国未来贸易引致的农业就业替代效应的程度和方式进行了模拟分析。研究结果表明:入世后我国农产品贸易引致的农业就业效应呈现出更明显的就业净替代变化;同时,在技术水平不变的情况下,我国未来劳动密集型农产品的实际出口增速与平抑就业替代压力的"理想增速"相距甚远,未来土地密集型净进口所产生的农业就业替代量将在较大程度上超过劳动密集型净出口创造的就业机会,我国农业就业整体"净替代"的趋势可能将长期持续。     

振动试验中常见问题的分析

振动试验是装备环境试验不可缺少的部分,本文分析了试验条件的制定、试验夹具的设计和试验样品安装等振动试验中比较重要的环节,提出了振动试验实施过程中常见的几个问题,并结合实际操作经验给出了解决方案。     

基于遥感技术的长江三角洲海岸带生态系统服务价值评估

长三角海岸带是长江三角洲与东海间的重要过渡性区域,基于联合国千年评估提出的生态系统服务框架,以生态学为原理、以遥感反演技术为手段、借助经济学方法,对2005年及2008年长三角海岸带的10项生态系统服务价值进行了评估。结果表明,长三角海岸带2005及2008年的生态系统服务总价值分别为1 235.92、1 493.04亿元,与长三角地区实际GDP对比得出,生态系统服务价值实际降低,海岸带生态环境退化;对于不同的生态系统来说,林地、耕地、湿地的生态系统服务价值较高,为增强生态系统可持续发展应重点加以保护;对于不同的生态系统服务功能来说,旅游娱乐服务、土壤保持、调节水源为价值量最大的3项服务,而调节空气质量、精神文化服务、养分循环为价值量最小的3项服务。     

A rapid and high-throughput quantum dots bioassay for monitoring of perfluorooctane sulfonate in environmental water samples

Currently HPLC/MS is the state of the art tool for environmental/drinking water perfluorooctane sulfonate (PFOS) monitoring. PFOS can bind to peroxisomal proliferator-activated receptor-alpha (PPARα), which forms heterodimers with retinoid X receptors (RXRs) and binds to PPAR response elements. In this bioassay free PFOS in water samples competes with immobilized PFOS in ELISA plates for a given amount of PPARα-RXRα. It can be determined indirectly by immobilizing PPARα-RXRα-PFOS complex to another plate coated with PPARα antibody and subsequent measuring the level of PPARα-RXRα by using biotin-modified PPARα-RXRα probes-quantum dots-streptavidin detection system. The rapid and high-throughput bioassay demonstrated a detection limit of 2.5 ng L⁻¹ with linear range between 2.5 ng L⁻¹ and 75 ng L⁻¹. Detection results of environmental water samples were highly consistent between the bioassay and HPLC/MS.     

Effect of aeration modes on the characteristics of composting emissions and the NH3 removal efficiency by using biotrickling filter

A pilot biotrickling filter (BTF) packed with ZX02 fibrous balls as packing material was tested for the treatment of ammonia (NH₃) released from a composting plant of dairy manure. In order to investigate the effects of three compost aeration modes (mode Co-I, Co-II and In-II) on the NH₃ removal efficiency, a field experiment was continuously carried out for more than eight months. The results demonstrated that under the intermittent aeration mode (In-II), the NH₃ removal efficiency reached 99.2 ± 0.1% when the inlet NH₃ concentration was 7.5-32.3 mg m⁻³ (9.8-42.5 ppmv). The maximum and critical elimination capacity of the biotrickling filter was 22.6 and 4.9 g NH₃ m⁻³ h⁻¹, respectively. The effluent concentration of NH₃ was lower than 1.0 mg m⁻³, which meets the first class discharge standards of GB14554-93. When the concentration of free ammonia in the trickling liquid was varied from 0.1 to 0.4 mg L⁻¹, the nitrification yield was between 47.9% and 103.8%. In addition, the optimum liquid tricking velocity (LTV) of the biotrickling filter was 0.5 m³ m⁻² h⁻¹ for low inlet concentrations and 2.2 m³ m⁻² h⁻¹ for high inlet concentrations. Therefore, the use of the biotrickling filter for the compost under the third aeration mode (In-II) yielded an effective optimum NH₃ removal and reduced the nitrogen loss in the compost.     

Persistent organic pollutants in food items collected in Hong Kong

This study aims to investigate levels of POPs in meat, edible oils, nuts, milk and wine collected from Hong Kong. Naphthalene, pp-DDE, beta-, gamma-HCH and PBDE 47 were detected in most of the food items. Goose liver accumulated the highest PAHs (47.9 ng g⁻¹ wet wt), DDTs (25.6), HCHs (13.0), PCBs (4.17), PBDEs (468 pg g⁻¹ wet wt) among all the selected food. Meat and nut groups had significant (p < 0.01 or 0.05) correlations between lipid contents and concentrations of PAHs (meat: r = 0.878), HCHs (meat: r = 0.753), DDTs (meat: r = 0.937; nuts: r = 0.968) and PCBs (meat: r = 0.832; nut: r = 0.946). The concentrations of DDTs, HCHs and PCBs in vegetable oil were lower, but HCHs in fish oil were higher, when compared with other countries. The concentrations of PAHs, DDTs, PCBs and PBDEs in food tested in the present study were all below various safety guidelines.     

Increased urinary 8-hydroxy-2��-deoxyguanosine levels in workers exposed to di-(2-ethylhexyl) phthalate in a waste plastic recycling site in China

Background

Di-(2-ethylhexyl) phthalate (DEHP) is a common plasticizer used in industrial and diverse consumer products. Animal studies indicate DEHP caused developmental, reproductive, and hepatic toxicities. However, human studies of the potential effects of DEHP are limited.

Methods

The exposed site with a history of over 20 years of waste plastic recycling was located in Hunan Province, China. The reference site without known DEHP pollution source was about 50 km far away from the exposed site. In this study, 181 workers working in plastic waste recycling and 160 gender?Cage matched farmers were recruited. DEHP concentrations in water and cultivated soil samples, serum thyroid-stimulating hormone, malondialdehyde (MDA), superoxide dismutase (SOD), urinary 8-hydroxy-2??-deoxyguanosine (8-OHdG), and micronuclei frequency in human capillary blood lymphocytes were analyzed.

Results

Mean levels of DEHP were greater in environment at the recycling site than at reference site (industry wastewater for the exposed: 42.43 ??g/l; well water: 14.20 vs. 0.79 ??g/l, pond water: 135.68 vs. 0.37 ??g/l, cultivated soil: 13.07 vs. 0.81 mg/kg, p?p?p?Conclusions The occupational DEHP exposure might contribute to oxidative deoxyribonucleic acid damage in the male workers.     

微波消解-ICP—MS测定土壤和水系沉积物中的重金属

建立了一种采用逆王水和氢氟酸的混合体系微波酸消解土壤与水系沉积物,电感耦合等离子体质谱法快速测定六种金属元素（As、Cd、Pb、Cu、Cr和Ni）含量的方法。本文研究了消解温度和消解时间对消解效果的影响。结果表明,在190℃下运行25分钟对土壤与水系沉积物中的六种金属元素均具有很好的消解能力,备元素的测定值与标准值相符。在对实际土壤与水系沉积物样品进行分析后得出采样区域的土壤与沉积物中这六种金属含量水平正常。     

生活垃圾焚烧处理方式的生命周期评价

与填埋、堆肥处理相比,生活垃圾焚烧处理在减量化和资源化方面有着巨大的优势,在未来将成为大城市生活垃圾的主要处理方式。采用生命周期评价方法,对不同余热利用和尾气处理方式下的生活垃圾焚烧处理方案对环境的影响进行评价。结果表明,在尾气处理系统中,干法、湿法、半干法3种酸性气体处理方式中,湿法处理的环境影响潜值最小,但是其资源耗竭系数最大。添加SNCR脱氮系统可以在酸性气体净化基础上将环境影响潜值降低70%左右,而资源耗竭系数变化不大。在单纯供热、供电和热电联供3种余热利用方式中,单纯供电的热利用效率最低,直接供热的热利用效率最高。