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1.
从润滑油的基础知识、轴承失效形式及机理等方面入手,重点分析机车牵引电机轴承润滑油在典型工况下的失效机理,找出机车牵引电机轴承润滑油在典型工况下的主要性能指标、检测方法以及各种试验规范,为典型工况下,轴承润滑油的失效分析提供理论和试验依据。 相似文献
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建立了黄瓜和土壤中啶氧菌酯残留量的检测分析方法,对啶氧菌酯在黄瓜和土壤中的消解动态及残留规律进行了研究。啶氧菌酯的最小检出量为3.5×10^-11g;在黄瓜和土壤基质中的最低检出浓度均为0.005mg·kg^-1。对黄瓜和土壤2种基质,设置了0.005、0.05、0.25 mg·kg^-13个添加水平,每个添加水平设置5个重复,啶氧菌酯在黄瓜和土壤中的添加回收率为68.61%-122.4%,变异系数为1.06%-17.2%。田间试验结果表明:啶氧菌酯在天津地区黄瓜和土壤中的残留消解半衰期分别为5.71d和12.9 d,在山东地区黄瓜和土壤中的残留消解半衰期分别为2.70d和10.3 d,在江苏地区黄瓜和土壤中的残留消解半衰期分别为9.76d和14.9 d。距最后一次施药5d时,啶氧菌酯在黄瓜中的最高残留量为0.014mg·kg^-1,远低于欧盟规定的黄瓜中啶氧菌酯最大残留限量0.05mg·kg^-1。 相似文献
3.
Seasonality of Soil Erosion Under Mediterranean Conditions at the Alqueva Dam Watershed 总被引:1,自引:0,他引:1
The Alqueva reservoir created the largest artificial lake of Western Europe in 2010. Since then, the region has faced challenges due to land-use changes that may increase the risk of erosion and shorten the lifetime of the reservoir, increasing the need to promote land management sustainability. This paper investigates the aspect of seasonality of soil erosion using a comprehensive methodology that integrates the Revised Universal Soil Loss Equation (RUSLE) approach, geographic information systems, geostatistics, and remote-sensing. An experimental agro-silvo pastoral area (typical land-use) was used for the RUSLE factors update. The study confirmed the effect of seasonality on soil erosion rates under Mediterranean conditions. The highest rainfall erosivity values occurred during the autumn season (433.6 MJ mm ha?1 h?1), when vegetation cover is reduced after the long dry season. As a result, the autumn season showed the highest predicted erosion (9.9 t ha?1), contributing 65 % of the total annual erosion. The predicted soil erosion for winter was low (1.1 t ha?1) despite the high rainfall erosivity during that season (196.6 MJ mm ha?1 h?1). The predicted annual soil loss was 15.1 t ha?1, and the sediment amount delivery was 4,314 × 103 kg. Knowledge of seasonal variation would be essential to outline sustainable land management practices. This model will be integrated with World Overview of Conservation Approaches and Technologies methods to support decision-making in that watershed, and it will involve collaboration with both local people and governmental institutions. 相似文献
4.
Ethical reflection deals not only with the moral standing and handling of animals, it should also include a critical analysis
of the underlying relationship. Anthropological, psychological, and sociological aspects of the human–animal-relationship
should be taken into account. Two conditions, asymmetry and ambivalence, are taken as the historical and empirical basis for
reflections on the human–animal-relationship in late modern societies. These conditions explain the variety of moral practice,
apart from paradoxes, and provide a framework to systematize animal ethical problems in a broader field. This allows the development
of ideal relationships as moral orientation across anthropocentric or sentientistic ethical theories. These ideal relationships
are called the patronage-model, the friendship-model and the partnership-model. The ethical problem of creating transgenic
animals is discussed in the light of these ideal relationships. 相似文献
5.
The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO(2) concentrations differed significantly between the urban (14.8 °C and 439 ppm CO(2)) and suburban (13.0 °C and 427 ppm CO(2)) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas. 相似文献
6.
利用Hopkinson压杆系统对PMMA变截面柱锥试样进行冲击加载,研究材料动态拉伸断裂特性和破坏机理。由于PMMA的拉压强度差别不大,采用圆柱状试件难以产生反射拉伸破坏,因此,将试样设计为圆柱锥状,实验时,将试样的圆柱端粘贴于输入杆上。实验结果表明,在一定的撞击速度下,由于应力波的汇聚作用,在试样锥段产生了反射拉伸破坏;当撞击速度较高时,在产生反射拉伸破坏的同时,试件中还产生了银纹区,随着打击速度的提高,银纹区域增大。同时根据断口的SEM观察,研究了材料的破坏机制。 相似文献
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Fuchaka Waswa Godfrey Netondo Lucy Maina Tabitha Naisiko Joseph Wangamati 《Journal of Agricultural and Environmental Ethics》2009,22(5):463-475
Although contract sugarcane farming is the most dominant and popular land use among farmers in Nzoia Sugarbelt, results from
a 2007 study suggests that the intended goal of increasing farmers’ incomes seems to have failed. With a mean monthly income
of Kenya Shillings 723 (US $ 10) from an average cane acreage of 0.38 hectares, it would be difficult for a household of eight
family members to meet their basic needs and lead a decent life. Analysis of farmer statements showed that up to 86% of the
changes in net income were significantly determined by six cost variables as a group (i.e., acreage, tillage costs, seedcane
costs, transport costs, yield, and farmer’s education level). Area under sugarcane had the greatest influence on net income
whereby an increase in one hectare under cane would result in an increase of Kenya Shillings 110,427 in net income (per crop
cycle of 21 months), holding other variables constant. This translates into Kenya shillings 5,258 per month (or 175 per day
per household, or for a family of eight people—KES 22 or US $ 10) from an average cane acreage of 0.38 hectares, it would be difficult for a household of eight
family members to meet their basic needs and lead a decent life. Analysis of farmer statements showed that up to 86% of the
changes in net income were significantly determined by six cost variables as a group (i.e., acreage, tillage costs, seedcane
costs, transport costs, yield, and farmer’s education level). Area under sugarcane had the greatest influence on net income
whereby an increase in one hectare under cane would result in an increase of Kenya Shillings 110,427 in net income (per crop
cycle of 21 months), holding other variables constant. This translates into Kenya shillings 5,258 per month (or 175 per day
per household, or for a family of eight people—KES 22 or US 0.3) per member, which is far below the international standard
of absolute poverty. Key net income depressors were tillage, seedcane, and transportation costs, all of which were determined
by the company with no input from farmers. To bridge income gaps between the company and farmers in favor of sustainable community
livelihoods, this paper argues strongly for the need to institutionalize Corporate Social Responsibility within the daily
operations of the company particularly to address net-income depressors. Ten key building blocks for such a policy for Nzoia
Sugar Company are suggested, based on farmers’ responses and ethical considerations. 相似文献
10.
Effects of Stonewalled Terracing Techniques on Soil-Water Conservation and Wheat Production Under Mediterranean Conditions 总被引:2,自引:0,他引:2
A field plot experiment was conducted in the Palestinian Autonomous Areas to study the effect of stonewalled terracing on soil and water conservation as compared to the nonterraced areas. Effects of the wheat canopy were considered as a second treatment. The experiment was undertaken over a period of two seasons (2000 and 2001). The results of the experiment found that the mean soil erosion was significantly lower (P < 0.05) in the terraced plots than in those that were nonterraced (182 kg/ha and 3525 kg/ha during the first season, 1769 kg/ha and 5057 kg/ha during the second season for terraced and nonterraced plots, respectively). A similar trend was observed with respect to runoff in areas under the same treatments. The wheat canopy showed lower, but not significant runoff and erosion in most of the cases for both seasons. Due to better soil and water conservation, the terraced plots obtained significantly higher total plant dry matter than nonterraced plots (1570 and 630 kg/ha in 2000, 2545 and 889 kg/ha in 2001 for terraced and nonterraced treatment, respectively). The runoff coefficient was 20% and 4% for the nonterraced and terraced plots, respectively. Rainstorms with intensity ≥4 mm/hand rainfall ≥10 mm are more likely to cause runoff and erosion. 相似文献
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Heather E. Golden Elizabeth W. Boyer Michael G. Brown S. Thomas Purucker René H. Germain 《Journal of the American Water Resources Association》2009,45(4):945-962
Abstract: Nitrate‐nitrogen (NO3‐N) concentrations in stream water often respond uniquely to changes in inter‐annual conditions (e.g., biological N uptake and precipitation) in individual catchments. In this paper, we assess (1) how the spatial distribution of NO3‐N concentrations varies across a dense network of nonnested catchments and (2) how relationships between multiple landscape factors [within whole catchments and hydrologically sensitive areas (HSAs) of the catchments] and stream NO3‐N are expressed under a variety of annual conditions. Stream NO3‐N data were collected during two synoptic sampling events across >55 tributaries and two synoptic sampling periods with >11 tributaries during summer low flow periods. Sample tributaries drain mixed land cover watersheds ranging in size from 0.150 to 312 km2 and outlet directly to Cayuga Lake, New York. Changes in NO3‐N concentration ratios between each sampling event suggest a high degree of spatial heterogeneity in catchment response across the Cayuga Lake Watershed, ranging from 0.230 to 61.4. Variations in NO3‐N concentrations within each of the large synoptic sampling events were also high, ranging from 0.040 to 8.7 mg NO3‐N/l (March) and 0.090 to 15.5 mg NO3‐N/l (October). Although Pearson correlation coefficients suggest that this variability is related to multiple landscape factors during all four sampling events, partial correlations suggest percentage of row crops in the catchments as the only similar factor in March and October and catchment area as the only factor during summer low flows. Further, the strength of the relationships is typically lower in the HSAs of catchment. Advancing current understanding of such variations and relationships to landscape factors across multiple catchments – and under a variety of biogeochemical and hydrological conditions – is important, as (1) nitrate continues to be employed as an indicator of regional aquatic ecosystem health and services and (2) a unified framework approach for understanding individual catchment processes is a rapidly evolving focus for catchment‐based science and management. 相似文献
12.
Corey Lee Wrenn 《Journal of Agricultural and Environmental Ethics》2016,29(2):143-165
Lack of diversity in the ranks as well as a failure to resonate with disadvantaged groups and other anti-oppression movements has been cited as one important barrier to the American Nonhuman Animal rights movement’s success (Kymlicka and Donaldson in Animal rights, multiculturalism and the Left. The Mellon Sawyer Seminar at the Graduate Center, CUNY. City University of New York, New York, 2013). It is possible that social movements are actively inhibiting diversity in the ranks and audience by producing literature that reflects a narrow activist identity. This article creates a platform from which these larger issues can be explored by investigating the actual demographic representations present in a small sample of popular media sources produced by the movement for other animals. A content analysis of 131 magazine covers produced by two highly visible movement actors, PETA and VegNews, was conducted to demonstrate that activist representations in at least some dominant American Nonhuman Animal rights media are mostly white, female, and thin. 相似文献
13.
采用田间试验方法研究了控释尿素不同施用条件对冬小麦产量、氮素利用和经济效益的影响。试验共设7个处理,即CK (空白处理,不施氮肥)、100%PU10/0(普通尿素全量基施,N 240 kg&#183;hm-2)、100%PU6/4(60%的普通尿素基施、40%的普通尿素于拔节期追施,N 240 kg&#183;hm-2)、80%PU6/4(60%的普通尿素基施、40%的普通尿素于拔节期追施,N 192 kg&#183;hm-2)、100%CRU(全量树脂包膜控释尿素基施,N 240 kg&#183;hm-2)、80%CRU(80%树脂包膜控释尿素基施,N 192 kg&#183;hm-2)和40%CRU+40%PU(40%树脂包膜控释尿素+40%的普通尿素基施,N 192 kg&#183;hm-2)。结果表明,无论是产量效应还是氮素利用效应,树脂包膜控释尿素(CRU)处理总体优于普通尿素(PU)处理,尤其树脂包膜控释尿素和普通尿素配施(40%CRU+40%PU)效果最佳,以7709 kg&#183;hm-2的产量、36.44%的氮肥吸收利用率、15946元&#183;hm-2的相对净收入达到处理间最高水平。该处理在减少氮素投入量的情况下,不仅促进了冬小麦增产,而且显著提高了肥料的利用率,拥有较高的产投比。因此,树脂包膜控释尿素和普通尿素的配施处理(40%CRU+40%PU)是本试验条件下最优的氮肥处理。 相似文献
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半导体器件失效案例统计与综合分析 总被引:2,自引:0,他引:2
电子元器件是电子产品最基本的组成部分,而半导体器件通常又是关键与核心器件;半导体器件失效数占电子元器件总失效数的一半以上。本文针对半导体器件的失效案例进行筛选、汇总,按照失效类别、失效模式和失效原因进行分类统计,并对统计数据进行分析;其结果可以为从事元器件质量管理、元器件研制、采购和整机设计人员在元器件研制、采购、试验、选用和使用等全过程控制半导体器件失效提供重要的参考数据。 相似文献
15.
《资源开发与市场》2016,(2)
农民由于对征地补偿不满而与地方政府产生冲突,以此为前提构造两者之间的演化博弈模型,对其博弈行为进行分析,讨论最终的演化稳定策略,并进行仿真分析,以说明如何达到理想的演化稳定策略解决征地冲突。通过博弈分析表明,对利益冲突的解决需要通过利益协商而非强制手段;博弈的关键在于地方政府如何根据被征地农民争取征地补偿的成本和对补偿的预期来确定合理的征地补偿增量;相对于农民争取征地补偿的成本而言,较高的征地补偿增量并不能解决利益冲突问题,很有可能适得其反,征地补偿增量接近或稍低才有可能达到理想的演化稳定结果。建议在土地征收中,地方政府应积极与农民沟通协商,拓宽农民的申诉渠道,充分了解农民的利益诉求;制定科学合理的土地补偿计算方法,公平分配征地收益。 相似文献
16.
本文根据20^#钢板镀铬材料在我国海洋环境的暴露结果,对20^#钢板镀铬材料在我国海洋环境条件下的腐蚀速度及腐蚀原因进行分析。 相似文献
17.
Continued concern for animal welfare may be alleviated when welfare would be monitored on farms. Monitoring can be characterized as an information system where various stakeholders periodically exchange relevant information. Stakeholders include producers, consumers, retailers, the government, scientists, and others. Valuating animal welfare in the animal-product market chain is regarded as a key challenge to further improve the welfare of farm animals and information on the welfare of animals must, therefore, be assessed objectively, for instance, through monitoring. Interviews with Dutch stakeholder representatives were conducted to identify their perceptions about the monitoring of animal welfare. Stakeholder perceptions were characterized in relation to the specific perspectives of each stakeholder. While producers tend to perceive welfare from a production point of view, consumers will use visual images derived from traditional farming and from the animals natural environments. Scientists perceptions of animal welfare are affected by the need to measure welfare with quantifiable parameters. Retailers and governments (policy makers) have views of welfare that are derived from their relationships with producers, consumers, non-governmental organizations (NGOs), and scientists. All interviewed stakeholder representatives stated that animal welfare is important. They varied in the extent to which they weighted economic considerations relative to concern for the animals welfare. Many stakeholders emphasized the importance of communication in making a monitoring system work. Overall, the perspectives for the development of a sustainable monitoring system that substantially improves farm animal welfare were assessed as being poor in the short term. However, a reliable system could be initiated under certain conditions, such as integrated chains and with influential and motivated stakeholders. A scheme is described with attention points for the development of sustainable monitoring systems for farm animal welfare in the long term. 相似文献
18.
Gustavo A. María Beatriz Mazas Francisco J. Zarza Genaro C. Miranda de la Lama 《Journal of Agricultural and Environmental Ethics》2017,30(6):809-826
Traditionally, in Spain bullfighting represents an ancient and well-respected tradition and a combined brand of sport, art and national identity. However, bullfighting has received considerable criticism from various segments of society, with the concomitant rise of the animal rights movement. The paper reports a survey of the Spanish citizens using a face-to-face survey during January 2016 with a total sample of 2522 citizens (1256 men and 1266 women). The survey asked about degree of liking and approving; culture, art and national identity; socio-economic aspects; emotional perception and animal welfare. The hypothesis proposed that the perception of bullfights may be affected by gender, age, occupation, origin and nationality of the persons surveyed. The hypothesis was confirmed. The majority of citizens surveyed do not like bullfights and great majorities do not attend or watch such events. Two extreme clusters were described: one representing favorable attitude towards bullfighting and other against bullfighting. The proportion of indifferent persons was important. Women and young people showed a more favorable attitude towards animal welfare issues associated with these events. Rural people were more accepting bullfights than urban people. Students were more anti-bullfight than those in other occupations. Additionally, technical economic factors made people favor more bullfights. The growth of claim against bullfights establishes an element of a far more multifaceted phenomenon that animal cruelty per se and support of a new paradigm called social change in countries as Spain. 相似文献
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电子信息行业长期以来都被定义为一个“高产值、低能耗”的清洁产业,其水环境压力经常被低估.以长三角电子信息产业集群的核心地区太湖流域为例,对电子信息行业的水资源消耗、废水和主要污染物排放以及危险废弃物的处置等方面进行了评估,发现高度集聚的巨大产能与特定区域水环境容量的矛盾、污染的产业链转移以及处于“微笑”曲线底部引致的环境投入压力是我国电子信息行业水环境压力的主要表现. 相似文献