开关型高压电网故障限流装置研制

针对日趋严重的电网短路电流超标问题,采用基于爆炸式快速开断载流桥体的大容量高速开关装置(Fast Switching Release,FSR)与限流电抗器一体技术研制了“节能型限流装置”,并在宁夏220 kV步桥变电站成功运行;基于高速大遮断容量真空断路器技术、短路电流快速识别技术、相控技术与限流电抗器相结合研制了“330 kV 开关型零损耗电网限流装置”,并在宁夏330 kV迎安I线成功进行2次短路试验。现场运行及试验结果表明:2种开关型高压电网故障限流装置从根本上解决了电网故障限流技术实用化中面临的安全性、可靠性以及经济性等关键问题,标志着电网故障限流技术取得了一个突破性的进展。     

Evaluation of the sustainable land use status of the North China Plain

The North China Plain is one of the most important production areas for wheat and maize in China, and also has the densest agricultural population in China. How to use and develop the limited land resources reasonably, and improve and protect them, have become issues of major concern. This paper is based on sustainability theory, reviewing the fundamental principles of sustainability, and developing an index system with which to evaluate the sustainability status of land use. We also use this method to evaluate the land-use status of the North China Plain and to analyze current factors affecting sustainable land use in this area. In addition, we propose a specific method for evaluating sustainable land use.     

地方性砷中毒地区环境砷暴露健康风险研究进展

自然因素引起的环境高砷暴露及其健康效应,尤其是饮水型地方性砷中毒是砷污染健康风险评估的基础。总结地方性砷中毒在环境砷暴露的风险识别、暴露途径和暴露与健康效应关系研究中的作用基础上,指出了地方性砷中毒研究中仅强调了饮水污染,关注的暴露途径比较单一,因此,人体多途径联合砷暴露的健康风险评估过程存在较大的不确定性。我国是唯一存在饮水和燃煤2种自然环境高砷暴露的国家,是研究2种类型砷暴露异同的天然场地,然而目前环境高砷的暴露及其健康效应的研究均为独立研究,对燃煤型地方性砷中毒在呼吸链砷暴露风险评估中的作用重视不够。因此,通过开展两种环境砷暴露及其健康效应的综合比较研究,建立呼吸链暴露评估和暴露-健康效应模型,可以为人体多途径联合砷暴露的健康风险研究提供新的依据。     

Removal of phenol by powdered activated carbon adsorption

In this study, the adsorption performance of powdered activated carbon (PAC) on phenol was investigated in aqueous solutions. Batch adsorption studies were performed to evaluate the effects of various experimental parameters like PAC type, PAC dose, initial solution pH, temperature and pre-oxidation on the adsorption of phenol by PAC and establish the adsorption kinetics, thermodynamics and isothermal models. The results indicated that PAC adsorption is an effective method to remove phenol from water, and the effects of all the five factors on adsorption of phenol were significant. The adsorption rate of phenol by PAC was rapid, and more than 80% phenol could be absorbed by PAC within the initial 10 min. The adsorption process can be well described by pseudo-second-order adsorption kinetic model with rate constant amounted to 0.0313, 0.0305 and 0.0241 mg·μg ^-1·min ^-1 with coal, coconut shell and bamboo charcoal. The equilibrium data of phenol absorbed onto PAC were analyzed by Langmuir, Freundlich and Tempkin adsorption isotherms and Freundlich adsorption isotherm model gave the best correlation with the experimental data. Thermodynamic parameters such as the standard Gibbs free energy (?G^o), enthalpy (?H^o) and entropy (?S^o) obtained in this study indicated that the adsorption of phenol by PAC is spontaneous, exothermic and entropy decreasing.     

Simultaneous analysis of five taste and odor compounds in surface water using solid-phase extraction and gas chromatography-mass spectrometry

In this paper, a method using solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) was developed to simultaneously analyze five taste and odor compounds in surface water, i.e., 2-methylisoborneol (2-MIB), 2,4,6-trichloroanisole (TCA), 2-isopropyl-3-methoxy pyrazine (IPMP), 2-isobutyl-3-methoxy pyrazine (IBMP), and trans-1,10-dimethyl-trans-9-decalol (geosmin, GSM). The mass spectrometry was operated in selective ion monitoring (SIM) mode. Three kinds of SPE columns and three eluting solvents were compared, the C18 column was chosen as optimum SPE column, and methanol was chosen as the optimum eluting solvent. It was found that the method showed good linearity in the range of 1–200 ng·L^-1 and gave detection limits of 0.5–1.5 ng·L^-1 for individual compounds. Good recoveries (93.5%–108%) and relative standard deviations (1.58%–7.31%) were also obtained. Additionally, concentrations of these taste and odor compounds in Jinan’s surface and drinking water were analyzed by applying this method, and the results showed that GSM and 2-MIB were the dominant taste and odor compounds in Jinan’s raw water.     

Plant diversity reduces the effect of multiple heavy metal pollution on soil enzyme activities and microbial community structure

It is unclear whether certain plant species and plant diversity could reduce the impacts of multiple heavy metal pollution on soil microbial structure and soil enzyme activities. Random amplified polymorphic DNA (RAPD) was used to analyze the genetic diversity and microbial similarity in planted and unplanted soil under combined cadmium (Cd) and lead (Pb) pollution. A metal hyperaccumulator, Brassica juncea, and a common plant, Festuca arundinacea Schreb, were used in this research. The results showed that microorganism quantity in planted soil significantly increased, compared with that in unplanted soil with Cd and Pb pollution. The order of microbial community sensitivity in response to Cd and Pb stress was as follows: actinomycetes>bacteria>fungi. Respiration, phosphatase, urease and dehydrogenase activity were significantly inhibited due to Cd and Pb stress. Compared with unplanted soil, planted soils have frequently been reported to have higher rates of microbial activity due to the presence of additional surfaces for microbial colonization and organic compounds released by the plant roots. Two coexisting plants could increase microbe population and the activity of phosphatases, dehydrogenases and, in particular, ureases. Soil enzyme activity was higher in B. juncea phytoremediated soil than in F. arundinacea planted soil in this study. Heavy metal pollution decreased the richness of the soil microbial community, but plant diversity increased DNA sequence diversity and maintained DNA sequence diversity at high levels. The genetic polymorphism under heavy metal stress was higher in B. juncea phytoremediated soil than in F. arundinacea planted soil.     

Phosphorus release potential and pollution characteristics of sediment in downstream Nansi Lake, China

The research aimed to evaluate present and potential phosphorous pollution due to high sedimentary phosphorus load and release from sediment, when external phosphorus was reduced in downstream Nansi Lake. Pollution load of the sediment and overlying water was investigated. Kinetics and isotherms of adsorption/release of sedimentary phosphorus were studied to determine equilibrium phosphate concentration (EPC₀) and release potential. Kinetics of phosphorus adsorption on sediment and release from sediment were well described by both the pseudo-first-order rate equation and the pseudo-second-order rate equation, but more appropriate to the pseudo-second-order rate equation with the adsorption/release capacity more close to the measured values, suggesting that the processes were chemically rate controlled and dependent on adsorption capacity. Soluble reactive phosphorus (SRP) sorption isotherms on sediment were best fitted by the modified Langmuir model indicating a monolayer adsorption. By comparing EPC₀ and SRP of water, the status (adsorption, releasing or in equilibrium) of sediment phosphorus could be determined. The sediments at site S1, S3, S4, S5, and S7 where the EPC₀s were greater than the SRPs, had a potential to release phosphorus into the water column. However, those sediments at S9, S10, and S12, where the EPC₀s were approximately equal to the SRPs, were in impermanent equilibrium with overlying water in status of phosphorus, the sediments can be likely to release phosphorus to the water column once the equilibrium was broken. Therefore, sedimentary phosphorus can be a secondary pollution source in downstream Nansi Lake.     

石油烃对栉孔扇贝血淋巴细胞DNA损伤的初步研究

为研究石油烃对海洋生物的毒性效应,将栉孔扇贝(Chlamys farreri)暴露于0.08、0.21和0.88mg·L-1石油烃中,采用单细胞凝胶电泳实验(彗星实验)技术检测不同暴露时间扇贝血淋巴细胞的DNA损伤程度,对照组中石油烃背景浓度为0.04mg·L-1。结果显示,低浓度(0.08mg·L-1)的石油烃短期(<7d)内即可导致栉孔扇贝血淋巴细胞的DNA损伤,并且随石油烃浓度的增大和暴露时间的延长,DNA损伤程度增加,石油烃浓度达0.88mg·L-1时,DNA损伤程度已非常严重。3d恢复实验后,各浓度组DNA损伤又均有不同程度的恢复。研究表明,彗星实验是检测石油烃对海洋贝类DNA损伤的一种有效手段,贝类血淋巴细胞DNA损伤有望成为石油烃污染的一种生物标志物,用于海洋污染的早期预警监测。     

简易垃圾填埋场综合治理方案

结合牛山简易垃圾填埋场综合治理工程,分别从简易填埋场的封场和防渗两方面进行了综合治理方案的研究。结果表明:以生活垃圾填埋场封场技术规程为指导,以垂直防渗帷幕作为防渗方案,在工程中切实可行,可以为简易填埋场的综合治理提供借鉴。