RF多功能芯片on-wafer评估系统的研究

评估RF多功能芯片在不同环境温度下的性能指标是十分重要的,从分析射频多功能芯片功能和主要性能指标出发,研制了一款自动化芯片在片评估系统。采用上位机进行多种芯片工作状态和设备仪器状态控制,实现了芯片在各种不同工作状态不同温度下的测试数据采集、判断和保存。经实际评估验证,该评估系统能高效高可靠性的完成射频多功能芯片在不同环境温度下的on-wafer级性能评估。     

耕作措施对土壤入渗产流影响的实验研究

采用人工模拟降雨和室内分析相结合的方法,研究了黄土区不同耕作措施对降雨入渗的影响。结果表明：①不同耕作管理措施对降雨入渗的影响效用不同,在相同雨强和坡度下,降雨入渗速率表现为：耙耱地〉人工掏挖〉直线坡,在中小雨强和较短滞后情况下,这种情况表现更为显著;②不同耕作管理措施对降雨产流的影响效用不同,在相同雨强和坡度下,产流滞后表现为：耙耱地〉人工掏挖〉直线坡,在中小雨强和较短滞后情况下,这种情况表现更为显著;③根据水量平衡原理,得出了不同耕作管理措施不同坡度下入渗及产流滞后随雨强的变化关系式。上述结果为黄土高原坡耕地水土流失的治理和管理,提供了一定的理论依据。     

不同温度下高压交联聚乙烯电缆绝缘老化程度检测方法

为了实现对不同温度下高压交联聚乙烯电缆绝缘老化程度检测,提出基于量化回归分析的高压交联聚乙烯电缆绝缘老化程度检测方法。构建不同温度下高压交联聚乙烯电缆绝缘老化程度的统计数据分析模型,采用谱特征分析方法进行不同温度下高压交联聚乙烯电缆绝缘老化程度的谱分析,提取反映不同温度下高压交联聚乙烯电缆绝缘老化程度的谱信息特征量,采用关联特征分析和定量递归图分析方法,进行不同温度下高压交联聚乙烯电缆绝缘老化程度的自适应检测,构建电缆绝缘老化程度的模糊相关性统计分析模型,结合模糊参数自适应寻优控制方法,实现电缆绝缘老化程度的检测优化设计。仿真结果表明,采用该方法进行电缆绝缘老化程度检测的准确性较高,检测结果可靠性较好。     

不同预案下的建设用地适宜性评价以湖北宜城市为例

以湖北宜城市为例,对宜城市未来不同发展模式和不同发展政策导向下的不同情景进行预测,设计基于目前发展趋势预案、城镇规划预案和生态环境保护预案的三种建设用地适宜性评价,利用ArcGIS软件的Model Builder建模评价三种预案下的建设用地适宜性。结果表明,不同预案下的建设用地适宜性评价结果存在着较大差别:城镇规划预案的各适宜区面积比例结构较均衡,其他两种预案的各适宜区比例结构不均衡;三种不同预案的高适宜区分布较集中,而中适宜区、低适宜区、不适宜区的分布特征在不同预案下的区别明显;将新增建设用地布局与各预案建设用地适宜性结果进行对比分析,城镇规划预案与新增建设用地布局最贴近,而生态环境保护预案的结果相差最大。由此可见,只有明确评价所基于的情景假设,才能使建设用地适宜性评价更科学合理。     

碳税下回收品不同质量水平制造/再制造企业运作策略研究CSSCI

在回收品不同质量水平的情况下,研究制造/再制造企业不同碳税下的最优运作。在多周期闭环混合系统中,需求由质量无差异的新产品和再制造品共同满足。假设回收品质量水平服从标准正态分布,回收成本、再制造成本、回收率是回收品质量水平的负指数函数,建立包含碳税成本(新产品和再制造品)在内的平均总成本模型,采用遗传算法(GA)、粒子群算法(PSO)验证模型的信度和效度。结果表明:企业可根据回收品的质量水平,合理安排再制造和制造批次来降低平均总成本;不同碳税水平下,合理的再制造和制造批次同样可降低总成本。该研究为企业在回收品不同质量水平下权衡碳排放因素降低总成本和政府制定合理的碳税政策提供参考。     

强噪音环境下基于震动信号的车辆适应性分析

传统的分析方法在强噪声环境下分析车辆适应性的能力较差,分析结果不准确,为了解决这一问题,基于震动信号研究了一种新的车辆适应性分析方法,采用场景模拟测试手段进行采集并记录不同强噪音干扰下小车的适应性,确定震动传感器系统的组成,在不同噪音频段和地点下采集数据,分别研究了发动机、工作轮胎与地面的摩擦、不同路面的状况对车辆适应性的影响,从震动结构和震动传感器两方面进行改进,提高车辆的适应性。实验结果表明,强噪音环境下基于震动信号的车辆适应性分析方法分析能力更强,分析结果准确率更高。     

高压电容器寿命试验检测装置的设计与实现

高压电容器在一定重复频率下的充放电寿命试验是考核其绝缘特性的关键指标,本文设计并制作了一个高压电容器寿命试验检测装置,它可以针对不同电容量的电容器进行不同电压和频率下的重复充放电试验.目前该检测装置己投入使用,正常工作超过1000小时.     

SC菌剂对废水中Cu~(2 )去除的初步研究

用研制的SC菌剂作生物吸附剂 ,研究了其在不同菌铜比 ,pH、温度及作用时间条件下对Cu2 的去除效果。结果表明 ,在获得的最佳条件下 ,对不同Cu2 浓度的印刷电路板废水中Cu2 的去除效果明显 ,达 95 48%和 86 74%。     

风力发电设备在我国不同气候条件下环境适应性分析

风力发电设备的环境适应性问题已经引起风电企业的重视,本文介绍了温度、湿度、盐雾、低气压、台风、雷电等环境因素对风力发电设备性能的影响,总结了我国不同地区和不同季节应该关注不同的环境因素,提出了风力发电设备在不同环境因素作用下的防护措施。     

沥青废气燃烧处理技术

在不同温度、不同沥青废气与天然气混合比及不同催化剂的条件下,用燃烧法对沥青熔化中产生的废气进行处理,研究其最佳处理效果,降低沥青废气排放浓度和废气中有害物质的浓度,解决了沥青废气严重污染环境的问题。     

An investigation of the relationship between raw coal characteristics and effluent quality of Kedla and Rajrappa Washeries, Jharkhand, India

An attempt was made to investigate the relationship between raw coal characteristics and effluent quality in two coking coal washeries of Central Coalfields Limited, Kedla and Rajrappa in Jharkhand State, India. Coal samples-raw coal feed, washed fine clean coal, washed coarse clean coal, middlings and rejects were collected. Similarly, raw water (intake to washery) and effluent samples generated in the washeries, namely, fine coal jig under water, coarse coal jig under water and slurry pond water were also collected over a period of 6 months. Parameters outlined in Ministry of Environment and Forest (MoEF) Schedule VI Indian standards were determined, both in coal samples and water/washery effluent samples. Apart from the parameters listed in the standard, sodium, potassium, calcium, magnesium, sulphate and chloride found to be present in coal were also determined in coal and water samples. The processing results essentially in production of huge quantities of suspended material, which is beyond the stipulated limit of 100mg/l as specified in the Standard. Lowering of pH was observed in both the washeries. The trace/heavy elements were found to be concentrated in the heavier fractions in rejects produced from the washery. The concentrations of major elements in coal-Na, K, Ca, Mg, and minor elements in coal-Mn; F, SO4 and Cl were found to be higher in process water than in raw water indicating that these elements are transferred from coal to the water in washeries. However, only in the case of Mn, the stipulated limit of the effluent standard was exceeded. Trace elements like As, Se, Hg, Cd, though found to be present in coal, were absent in the process water indicating that these elements are not released by coal during washing.     

Study of Fractionation and Potential Mobility of Metal from the Guadalquivir Estuary: Changes in Mobility with Time and Influence of the Aznalcollar Mining Spill

This study analyzed the evolution of metal levels in surface sediments from the Guadalquivir estuary between 1997 and 2002 and assessed the impact of the April 1998 Aznalcollar tailings dam failure and subsequent cleanup on metal concentrations in surface sediments. We also analyzed metal distribution with time in five chemical fractions of the surface sediments: exchangable, carbonate, reducible, oxidizable, and residual. This work showed that the April 1998 Aznalcollar tailings dam failure caused a considerable increase in the concentrations of Cd, Zn, Cu, and Pb in the surface sediments of the Guadalquivir estuary. It was also found there was a change in the distribution of Cd, Zn, Cu, and Pb between the chemical fractions of the sediment after the failure of the dam. There were increases in the percentages of Cd in the carbonate fraction, of Zn and Pb in the reducible fraction, and of Cu in the oxidizable fraction, whereas the percentages of these elements associated with the residual fraction decreased. In 1999, there was a decrease in the metal concentrations in the surface sediments from the Guadalquivir estuary, and by 2000 the chemical distribution and metal levels had returned to levels similar those before the dam failure.     

Assessing the impact of leather industries on the quality of water discharged into the East China Sea from Wenzhou Watersheds

Ammonium nitrogen and total germanium are among the main pollutants in the wastewater discharged from the leather industry. The intake of high concentrations of ammonium nitrogen and/or total germanium harms human health and biological species, as is well documented in literature. This paper focuses on assessing the trends of ammonium nitrogen and total germanium concentrations through time in two watersheds (Aojiang and Oujiang) in the Wenzhou metropolitan area of Zhejiang Province and their relationships with the released wastewater using regression and correlation statistics. The paper also utilizes the integrated pollution index to evaluate water quality in the two watersheds. Preliminary results show that, from 1992 to 1998 in the Aojing watershed, the concentrations of ammonium nitrogen and total germanium increased 13 and 14 times, respectively, decreasing somewhat after 1998, while between 1992 and 1997 in the Oujiang watershed, the concentrations increased, then decreased after 1997. The concentrations of ammonium nitrogen and total germanium are positively related to the amount of released wastewater. The concentrations of ammonium nitrogen and total germanium exceeded water standards 12 and 3 times, respectively, in Pingyang county of the Aojiang watershed, 14 and 3.3 times in Lucheng District of the Oujiang watershed, and 14 and 3.8 times in the Ouhai Oujiang watershed, respectively. In Pingyang county of the Aojiang watershed, the water quality degraded from Type III in 1992 to over Type V in 2003, and in the Oujiang watershed, the water quality degraded from Type II to over Type IV in 1999, when they were compared with the water quality standards. The water quality slightly improved in 2003 for the Oujiang watershed. It appears that pollution did have a direct positive correlation with leather industry production in the Pingyang Aojing watershed, while there was a negative correlation between the two in the Oujiang watershed. In these two watersheds, the integrated pollution index did not appear to relate to population dynamics and agricultural production. This paper also discusses the current new methodologies and approaches adopted nationally and internationally to reduce the contaminants and purify the environment for maintaining a sustainable and healthier environment in Wenzhou.     

Plant-available zinc and lead in mine spoils and soils at the mines of Spain, Iowa

To investigate the forms of Zn and Pb and their plant availability in mine spoil long after its abandonment, we studied seven sites in the Mines of Spain, near Dubuque, IA. Ores of Zn and Pb were mined from dolomitic limestone primarily during the 19th century, and there had been no subsequent remediation of metals-contaminated spoil. From both mine spoil and undisturbed areas, we collected root-zone soil samples as well as samples of the dominant ground-level, native plants, aniseroot [Osmorhiza longistylis (Torr.) DC.] and black snakeroot (Sanicular marilandica L.). We determined Zn and Pb concentrations in both the plant tissue and in the soil samples after strong-acid digestion, and we fractionated the solid-phase forms of Zn, Pb, and P in the soil samples by using sequential extraction. Concentrations of total Zn and Pb were 10- to 20-fold greater in the spoil than in the undisturbed soils. Plants growing in the mine spoil had Zn concentrations two to four times greater and Pb concentrations more than 26 times greater than did plants growing in the undisturbed soils. The highest concentrations of Zn and Pb were in the CBD-extractable and the residual fractions in both undisturbed and mine spoil samples. Although the mine spoil contained large amounts of P, Zn, and Pb were available for uptake by the two plant species in amounts proportional to Zn and Pb concentrations in the rooting zone.     

土壤微塑料污染及其分析方法

微塑料作为环境介质中的新型污染物,其对生态系统的影响越来越受到关注。土壤是环境中微塑料的重要蓄积库,结合近些年来国内外关于土壤中微塑料的研究,针对土壤中微塑料的来源、生态效应、分析方法及污染防治进行综述,以便更全面的了解土壤中微塑料污染的现状及其潜在的生态环境风险。塑料包装废弃物、农用地膜破碎、大气沉降是土壤中微塑料的主要来源。微塑料可吸附土壤中的重金属和有机物,作为其他污染物的载体危害生态环境健康,并会随着食物链逐渐富集,从而影响人类健康。土壤中的微塑料可通过筛分干燥后采用密度分离法、加压流体萃取法、石油提取法等进行分离,并通过消解去除土壤中的有机质。土壤中微塑料的识别与表征可采用目检法、红外光谱法、拉曼光谱法、扫描电镜法等。此外,根据土壤微塑料的生态效应提出污染治理措施与未来研究方向展望。     

Forest Management in Northeast China: History,Problems, and Challenges

Studies of the history and current status of forest resources in Northeast China have become important in discussions of sustainable forest management in the region. Prior to 1998, excessive logging and neglected cultivation led to a series of problems that left exploitable forest reserves in the region almost exhausted. A substantial decrease in the area of natural forests was accompanied by severe disruption of stand structure and serious degradation of overall forest quality and function. In 1998, China shifted the primary focus of forest management in the country from wood production to ecological sustainability, adopting ecological restoration and protection as key foci of management. In the process, China launched the Natural Forest Conversion Program and implemented a new system of Classification-based Forest Management. Since then, timber harvesting levels in Northeast China have decreased, and forest area and stocking levels have slowly increased. At present, the large area of low quality secondary forest lands, along with high levels of timber production, present researchers and government agencies in China with major challenges in deciding on management models and strategies that will best protect, restore and manage so large an area of secondary forest lands. This paper synthesizes information from a number of sources on forest area, stand characteristics and stocking levels, and forest policy changes in Northeastern China. Following a brief historical overview of forest harvesting and ecological research in Northeast China, the paper discusses the current state of forest resources and related problems in forest management in the region, concluding with key challenges in need of attention in order to meet the demands for multi-purpose forest sustainability and management in the future.     

Changes in Upland Wildlife Habitat on Farmland in Illinois 1920–1987

/ An index of upland wildlife habitat was developed to investigate patterns and changes in habitat over time, using four years (1920, 1940, 1964, 1987) and the state of Illinois as an example. The index was composed of two subdivisions that described, at the county level, the quantity of wildlife habitat and a third subdivision that described farming disturbances that impacted the quality of the habitat. Data came from the US Census of Agriculture. The first subdivision that reflected quantity of habitat was called the wildlife habitat subdivision and was the sum of percentage woodland on farms, percentage farmland in nonrow crops, and percentage farmland in set-aside programs. The second subdivision that reflected the quantity of habitat was termed the soil-related features subdivision and was the sum of the percentage of farmland that was not highly erodible, the percentage of farmland in soil-protecting crops, and the percentage of farmland in conservation tillage. The third subdivision, reflecting the quality of the habitat, was the farming disturbance subdivision and was the sum of the percentage of grazing and the percentage of land on which fertilizers, pesticides, and herbicides were applied. Overall, major decreases occurred between 1920 and 1987 in the subdivisions reflecting the quantity of wildlife habitat and a major increase occurred in the subdivision associated with farming disturbance, reflecting the intensification of agriculture in the state. However, there was variability throughout the state, with some counties being more favorable to wildlife (as measured by the subdivisions) than others. Most of the changes within the state for the subdivisions reflecting quantity of upland wildlife habitat occurred during 1940 while changes in the farming disturbance subdivision (reflecting habitat quality) occurred in 1964. By 1987, the western and southern parts of Illinois were the most favorable for wildlife as reflected in all three subdivisions. Upland wildlife harvest indices were related to the subdivisions in 1964 and 1987, when harvest indices were available. Cottontail and northern bobwhite harvests were higher in counties with higher amounts of the wildlife habitat subdivision in both years. Cottontail harvest was also higher in counties with lower levels of the farming disturbance subdivision in 1964 and higher levels of soil-related features subdivision in 1987. Indices at the county level have the potential to be used in a multiscale analysis to investigate the impact of policy changes on large-scale areas of the Midwest and to develop regional perspectives of the impacts of agriculture on upland wildlife and their habitats.KEY WORDS: Upland wildlife; Habitat; Agriculture; Illinois     

Traditional Land-Use Systems and Patterns of Forest Fragmentation in the Highlands of Chiapas, Mexico

The influence of slash-and-burn agriculture and tree extraction on the spatial and temporal pattern of forest fragmentation in two municipalities in the highlands of Chiapas, Mexico was analyzed. The data series were derived from two subsets of satellite images taken in 1974 and 1996. The analysis was based on area, edge, shape, core area, and neighbor indices. During the 22 years, the dense forest decreased by 8.9%/yr in Huistán and by 8.6%/yr in Chanal, while open/disturbed forest, secondary vegetation, and developed area increased in both municipalities. The total number of fragments increased by 1.4%/yr and 2.3%/yr in Huistán and Chanal, respectively. Dense forest showed the highest increase in the number of fragments (6%/yr in Huistán and 12%/yr in Chanal), while edge length, core area, and number of dense forest core areas decreased. The larger fragments of dense forest present in 1974 were divided into smaller fragments in 1996; at the same time, they experienced a process of degradation toward open/disturbed forest and secondary vegetation. Two different fragmentation patterns could be distinguished based on agricultural or forestry activities. Forest fragmentation did not occur as a continuous process; the pattern and degree of fragmentation were functions of land tenure, environmental conditions, and productive activities. The prevalence of rather poor soil conditions, small-holdings, growing human population densities, increasing poverty, and the absence of alternative economic options will maintain a high rate of deforestation and forest fragmentation in the studied region.