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721.
本文综述了天然水相(大气水相、地表水等)中Fe(Ⅲ)-草酸盐配合物的含量与分布、光化学性质、对天然水相中有机物的降解、及其在废水光化学处理中的应用研究及前景。  相似文献   
722.
Atmospheric simulation chambers,are unique tools for investigating atmospheric processes in the gas and heterogeneous phases.They can provide a controlled yet realistic environment that simulates atmospheric conditions.In the current study,a Teflon atmospheric simulation chamber of 600 L,named THALAMOS(thermally regulated atmospheric simulation chamber) has been developed and cross-validated.THALAMOS can be operated over the temperature range 233 to 373 K under both static and flow conditions.It...  相似文献   
723.
724.
为达到企业安全经济效益最大化的目标,运用系统动力学的方法对企业安全经济效益系统进行建模,并对其中的安全教育经济效益子系统进行仿真模拟。实验结果表明:改变系统中的影响因素,安全教育经济效益并没有立即发生变化,而存在一段“延迟阶段”。同时也证明了安全培训人员能力在安全教育经济效益系统中具有最大的影响效果。  相似文献   
725.
喷嘴角度对脱硫塔内气液两相流场的影响   总被引:1,自引:0,他引:1  
提出了采用数值模拟的方法研究喷嘴角度对脱硫塔内部气液两相流场的影响。由于实际脱硫塔尺寸庞大,给实验研究带来困难且成本很高,在数值模拟平台上,分别模拟了45°、75°和-30°3种喷嘴角度布置下脱硫塔内部速度场、温度场变化以及湍流强度的分布情况。结果表明,在角度为-30°布置时速度场变化不是很剧烈,脱硫塔进出口温差比较理想,湍流强度在脱硫塔底部较大随着塔高的增加缓慢降低,这样有助于气液两相均匀混合,并控制出口烟温,有利于提高脱硫效率。  相似文献   
726.
Volatile organic compounds at swine facilities: A critical review   总被引:3,自引:0,他引:3  
Ni JQ  Robarge WP  Xiao C  Heber AJ 《Chemosphere》2012,89(7):769-788
Volatile organic compounds (VOCs) are regulated aerial pollutants that have environmental and health concerns. Swine operations produce and emit a complex mixture of VOCs with a wide range of molecular weights and a variety of physicochemical properties. Significant progress has been made in this area since the first experiment on VOCs at a swine facility in the early 1960s. A total of 47 research institutions in 15 North American, European, and Asian countries contributed to an increasing number of scientific publications. Nearly half of the research papers were published by U.S. institutions.Investigated major VOC sources included air inside swine barns, in headspaces of manure storages and composts, in open atmosphere above swine wastewater, and surrounding swine farms. They also included liquid swine manure and wastewater, and dusts inside and outside swine barns. Most of the sample analyses have been focusing on identification of VOC compounds and their relationship with odors. More than 500 VOCs have been identified. About 60% and 10% of the studies contributed to the quantification of VOC concentrations and emissions, respectively. The largest numbers of VOC compounds with reported concentrations in a single experimental study were 82 in air, 36 in manure, and 34 in dust samples.The relatively abundant VOC compounds that were quantified in at least two independent studies included acetic acid, butanoic acid (butyric acid), dimethyl disulfide, dimethyl sulfide, iso-valeric, p-cresol, propionic acid, skatole, trimethyl amine, and valeric acid in air. They included acetic acid, p-cresol, iso-butyric acid, butyric acid, indole, phenol, propionic acid, iso-valeric acid, and skatole in manure. In dust samples, they were acetic acid, propionic acid, butyric acid, valeric acid, p-cresol, hexanal, and decanal. Swine facility VOCs were preferentially bound to smaller-size dusts.Identification and quantification of VOCs were restricted by using instruments based on gas Chromatography (GC) and liquid chromatography (LC) with different detectors most of which require time-consuming procedures to obtain results. Various methodologies and technologies in sampling, sample preparation, and sample analysis have been used. Only four publications reported using GC based analyzers and PTR-MS (proton-transfer-reaction mass spectrometry) that allowed continuous VOC measurement. Because of this, the majority of experimental studies were only performed on limited numbers of air, manure, or dust samples. Many aerial VOCs had concentrations that were too low to be identified by the GC peaks.Although VOCs emitted from swine facilities have environmental concerns, only a few studies investigated VOC emission rates, which ranged from 3.0 to 176.5 mg d−1 kg−1 pig at swine finishing barns and from 2.3 to 45.2 g d−1 m−2 at manure storages. Similar to the other pollutants, spatial and temporal variations of aerial VOC concentrations and emissions existed and were significantly affected by manure management systems, barn structural designs, and ventilation rates.Scientific research in this area has been mainly driven by odor nuisance, instead of environment or health concerns. Compared with other aerial pollutants in animal agriculture, the current scientific knowledge about VOCs at swine facilities is still very limited and far from sufficient to develop reliable emission factors.  相似文献   
727.
Polybrominated diphenyl ethers (PBDEs), commonly used flame retardants, have been reported as potential endocrine disruptor and neurodevelopmental toxicants, thus giving rise to the public health concern. The goal of this study was to investigate the relationship between umbilical cord blood, maternal blood, and breast milk concentrations of PBDEs in South Korean. We assessed PBDE levels in paired samples of umbilical cord blood, maternal blood, and breast milk. The levels of seven PBDE congeners were measured in 21 paired samples collected from the Cheil Woman’s Hospital (Seoul, Korea) in 2008. We also measured thyroid hormones levels in maternal and cord blood to assess the association between PBDEs exposure and thyroid hormone levels. However, there was no correlation between serum thyroxin (T4) and total PBDEs concentrations. The total PBDEs concentrations in the umbilical cord blood, maternal blood, and breast milk were 10.7 ± 5.1 ng g−1 lipid, 7.7 ± 4.2 ng g−1 lipid, and 3.0 ± 1.8 ng g−1 lipid, respectively. The ranges of total PBDE concentrations observed were 2.28-30.94 ng g−1 lipid in umbilical cord blood, 1.8-17.66 ng g−1 lipid in maternal blood, and 1.08-8.66 ng g−1 lipid in breast milk. BDE-47 (45-73% of total PBDEs) was observed to be present dominantly in all samples, followed by BDE-153. A strong correlation was found for major BDE-congeners between breast milk and cord blood or maternal blood and cord blood samples. The measurement of PBDEs concentrations in maternal blood or breast milk may help to determine the concentration of PBDEs in infant.  相似文献   
728.
采用固相萃取-高效液相色谱-电喷雾电离质谱法测定饮用水源地地表水中痕量微囊藻毒素MC-LR,优化了色谱和质谱条件,以甲醇/水(含0.1%甲酸)混合溶液(体积比60:40)为流动相,选择定量离子质荷比(m/z)996.3.方法在0.100 mg/L-2.00 mg/L范围内线性良好,检出限为0.02 μg/L,空白水样加...  相似文献   
729.
萃取技术在环境样品预处理中的应用及发展   总被引:8,自引:0,他引:8  
对萃取技术包括传统技术以及新近发展起来的如固相萃取、固相微萃取、膜萃取、超临界流体萃取、微波萃取等技术在环境样品预处理方面的运用进行综述,分析各自的优缺点以及发展前景.  相似文献   
730.
固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点。文章用固相微萃取富集水中9种硝基苯类及5种氯苯类化合物,毛细管气相色谱ECD检测器分离分析,整个分析过程只需25min,检出限可达0.0002~0.02μg/L,已用于地表水、海水与工厂废水中硝基苯类及氯苯类化合物含量的测定。  相似文献   
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