在干扰环境中测量局部放电的新原理——调谐平衡法

传统的避部放电平衡测量法以电阻电容为输入电路，存在许多缺点，难以在高压和超高压领域推广使用，本文以电感电容为输入电路；全面分析了调谐平衡法局部放电测试管理；模拟实验的结果表明，在选定的测量中心频率下，在调谐电容的调节范围内，存在着无数组平衡点，试样与参考电容器的电容量可相差１００倍。干扰的抑制比可高达２０００－４０００。     

Treatment of pretreated coking wastewater by flocculation,alkali out,air stripping,and three-dimensional electrocatalytic oxidation with parallel plate electrodes

The coking wastewater generally comprises highly concentrated, recalcitrant, and toxic organic pollutants, so its treatment has been of great importance to prevent living beings and their environment from these hazardous contaminations. The treatment of pretreated coking wastewater by flocculation-coagulation, alkali out, air stripping, and three-dimensional (3-D) electrocatalytic oxidation was performed (gap between the used β-PbO₂/Ti anode and titanium cathode, 12 mm; mass ratio of Cu-Mn/granular activated carbon (GAC) to effluent, 1:4; cell voltage, 7 V). The results showed that the pH adjusting from 3.7 to 6.1 was necessary for coagulants; alkali out played an important role because it brought up precipitation containing higher fatty acids as well as other contaminants to decrease the chemical oxygen demand (COD) in the effluent, and it had also forced the reduction of ammonia nitrogen (NH₃-N) by incorporating with air stripping; for 3-D electrocatalytic oxidation with a bleaching liquid assisting, the initial pH 8.5 of effluent was suitable for Cu-Mn/GAC; moreover, it was considered that its Cu component was dedicated to the decrease of COD and NH₃-N, while the Mn component specialized in the decay of NH₃-N. The residual COD and NH₃-N values in the final effluent with pH 6.5 were 95.8 and 8.8 mg/L, respectively, demonstrating that the whole processes applied were feasible and low in cost.     

Heterogenous impacts of components in urban energy metabolism: evidences from gravity model

Environment, Development and Sustainability - The undergoing rapid urbanization is bringing dramatic economic development and social improvement for cities, but also a series of problems associated...     

未来十年中国煤炭碳排放量预测

应对全球气候变化,低碳经济是实现经济社会可持续发展的一种模式。为了对低碳经济进行深入研究,把握中国低碳经济研究文献现状是很有必要的,但运用文献计量学的方法对低碳经济进行定量方面的研究也是相当的必要。本文在对近十年中国煤炭碳排放量计算的基础上,运用移动平均法、滑动平滑法和回归分析法三种方法对未来十年中国煤炭碳排放量进行预测。预测结果表明:与近十年中国煤炭碳排放量相比,未来十年中国煤炭碳排放年均增长率虽有降低,但碳排放增长总量却呈上升的趋势。     

“自由落体”游乐设备直流电机故障分析

创新是大型游乐设施占领市场的核心竞争力,但创新也容易引发各类问题及不确定性,特别是涉及游乐设备可维护性方面,更容易在创新过程中忽视。本文以国外设备供应商生产的“自由落体”游乐设备的故障入手,从研究直流电机故障机理、维修方案以及设计维保建议等几个方面,提出提升直流电机可维护性的举措,主张行业的设计人员不但要聚焦大型游乐设施的趣味性,也要更多关注如何提高大型游乐设施的可靠性、可维护性。     

A laboratory study of the persistence of carbofuran and its 3‐hydroxy‐ and 3 keto‐metabolites in sterile and natural mineral and organic soils

Abstract

In a laboratory study, the persistence of carbofuran and its 3‐hydroxy‐ and 3‐keto‐metabolites was examined separately over 16 wk in sterile and natural organic (muck) and mineral (loam) soils. Carbofuran was relatively persistent in sterile soils; at 8 wk 77% remained in the sterile muck and about 50% remained in the sterile loam. In the natural muck 25% of initial carbofuran remained at 8 wk whereas in the natural loam carbofuran had completely disappeared by that time. The 3‐ketocarbofuran was very short‐lived even in the sterile muck where only 50% remained at 1 wk. The 3‐hydroxycarbofuran degraded appreciably on zero day in the natural soils (with conversion to 3‐ketocarbofuran) and about 90% had disappeared in 1 wk. A more detailed study of the persistence of 3‐hydroxycarbofuran in the natural soils showed complete disappearance in 2 days in loam and in 3 days in muck. The 3‐ketocarbofuran produced from the 3‐hydroxy‐carbofuran reached a maximum concentration in 1 day and then disappeared within 4 days in loam and about 1 wk in muck.     

Southeastward transport of Asian dust: Source,transport and its contributions to Taiwan

Atmospheric Aluminum measured in northern Taiwan from 2003 to 2006 is used as a dust tracer, from which dust concentrations are derived, and major Asian dust events are determined. The source locations for the major dust events are traced back and identified, and the processes leading to the southeastward transport of Asian dust is investigated. The derived dust concentrations are compared to the local PM₁₀ (particle with size less than 10 μm) concentrations, and the impacts of Asian dust on the air quality of Taiwan are quantified.According to the backward trajectory and dust observation analyses, most of the southeastward transport of major Asian dust events originate from Mongolia and Inner Mongolia in northern China, and only one out of 16 events is generated from western China. Modeling studies and weather analyses of dust events suggest that the southeastward transport of Asian dust is usually generated behind a surface front and transported downwind behind the associated upper level trough. The associated upper level trough is usually deep, in which the northwesterly wind behind the trough favors the southeastward transport of dust to lower latitudes. Dust transported to Taipei generally occur during periods of large-scale subsidence.Asian dust contributes about 15 μg m^?3 of aerosol particles to northern Taiwan during winter monsoon, which accounts for about 24–30% of the PM₁₀ concentrations to the northern Taiwan. The contributions of Asian dust are raised pronouncedly to about 60–70% during major dust events. The impacts of Asian dust on Taiwan's air quality are most substantial in December. The Asian dust impacts decrease in other months, but still remain at around 30% in the late winter to early spring.     

Effect of selected herbicides on activities of microorganisms in soils

Abstract

With the exception of EPTC, herbicide treatments showed inhibitory effects on bacterial colony counts in a sandy loam soil for the first week. Monolinuron and simazine were stimulatory to the growth of fungi in the organic soil after 2 wk. None of the herbicide treatments affected nitrification during the first week of incubation. Except the treatment of EPTC in organic soil, all herbicides inhibited nitrification after 2 wk in both soils. All herbicide treatments stimulated SO₄ formation during the 8‐wk period in the sandy loam soil. Simazine and tridiphane also stimulated sulfur oxidation after 4 wk in an organic soil. With the exception of EPTC and nitrapyrin, no significant inhibitory effect on the amount of biomass‐C was observed in the organic soil. A stimulatory effect on denitrification was observed with EPTC for 2 wk and monolinuron for 1 wk in the sandy loam soil and with simazine and tridiphane after 2 wk in the organic soil. It is apparent that the indigenous soil microorganisms can tolerate the effects of the chemicals for control of soil weeds.     

Spatial Variations in the Relationships between Land Use and Water Quality across an Urbanization Gradient in the Watersheds of Northern Georgia, USA

A spatial statistical technique, Geographically Weighted Regression (GWR) is applied to study the spatial variations in the relationships between four land use indicators, including percentages of urban land, forest, agricultural land, and wetland, and eight water quality indicators including specific conductance (SC), dissolved oxygen, dissolved nutrients, and dissolved organic carbon, in the watersheds of northern Georgia, USA. The results show that GWR has better model performance than ordinary least squares regression (OLS) to analyze the relationships between land use and water quality. There are great spatial variations in the relationships affected by the urbanization level of watersheds. The relationships between urban land and SC are stronger in less-urbanized watersheds, while those between urban land and dissolved nutrients are stronger in highly-urbanized watersheds. Percentage of forest is an indicator of good water quality. Agricultural land is usually associated with good water quality in highly-urbanized watersheds, but might be related to water pollution in less-urbanized watersheds. This study confirms the results obtained from a similar study in eastern Massachusetts, and so suggest that GWR technique is a very useful tool in water environmental research and also has the potential to be applied to other fields of environmental studies and management in other regions.     

生物脱氮除磷新工艺的研究进展

传统的脱氮除磷工艺存在许多不足之处 ,经济、高效、低耗的可持续脱氮除磷工艺已成为污水处理的发展方向。在分析中 ,介绍了运用短程硝化反硝化、厌氧氨氧化、反硝化除磷理论的工艺 :SHARON工艺、CANON工艺、ANAMMOX工艺、SHARON与ANAMMOX联合工艺、DEPHANOX工艺、BCFS○R工艺的机理和研究进展