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491.
基于灰色理论的甲型H1N1流感传染人数预测模型研究 总被引:1,自引:0,他引:1
就我国甲型H1N1流感传染人数的预测运用灰色系统理论,建立了GM(1,1)模型和1阶残差修正模型GMε(1,1),并分别作了精度分析。研究了GMε(1,1)的变化趋势,提出了临界值和有效域概念。用MATLAB确定了模型参数及模型预测值。 相似文献
492.
用酶联免疫检测方法对苏州河沉积物PCDD/Fs进行分析,结果表明,PCDD/Fs水平在3.6~13.7TEQpg/gdw之间(平均值为8.4TEQpg/gdw)。PCDD/Fs含量的空间分布差异较大,中游含量高于上游和下游。对柱状沉积物的分析显示,沉积物PCDD/Fs含量在9.0~18.8TEQpg/gdw之间(平均值为13.8TEQpg/gdw),1996年前后达到峰值。通过对苏州河PCDD/Fs组成模式进行主分量分析发现,河流沉积物的PCDD/Fs为混合来源,其中污水排放的贡献较大。 相似文献
493.
城区内小型加油站的消防安全对策 总被引:1,自引:0,他引:1
通过对遵义市高庄(东)加油站进行实例分析,发现加油站安全管理体制不健全,违章作业表现突出,存在消防安全隐患;结合实例分析结果,得出城区内小型加油站的消防安全对策. 相似文献
494.
Choi YH Kang HS Jun I Keum DK Park HK Choi GS Lee H Lee CW 《Journal of environmental radioactivity》2007,93(3):157-169
The transfer of 90Sr to rice plants following its acute ground deposition was examined experimentally in a greenhouse. Lysimeters were flooded after being filled with the soil monoliths from 12 paddy fields. A solution of 90Sr was applied to the standing water in the flooded lysimeters at the pre-transplanting stage or booting stage. Applied 90Sr was mixed with the topsoil only after the pre-transplanting application (PTA). The transfer was quantified with the areal transfer factor (TF(a), m2 kg(-1)-dry) defined as the ratio of the plant concentration to the initial ground deposition. In the PTA, the first-year TF(a) values in the 12 soils were in the range of 8.2 x 10(-3) -2.1 x 10(-2) and 1.7 x 10(-4) -3.6 x 10(-4) for the straws and hulled seeds, respectively. The TF(a) values from the booting-stage application (BSA) were higher than those from the PTA by a factor of up to four. The ratios of the seed TF(a) to the straw TF(a) were, on the whole, higher in the BSA. The 90Sr TF(a) in the PTA was negatively correlated with the soil pH and, to a lesser degree, the exchangeable Ca content. In the second year, the TF(a) in the PTA reduced to 53-90% of that in the first year. A more significant reduction, in general, occurred in a sandier soil. Based on the four consecutive years' transfer data, an overall half-time of the 90Sr TF(a) was estimated to be 2.2 years. 相似文献
495.
对于烟气脱硫系统,准确测定烟气中雾滴浓度是完成脱硫系统性能考核的必备技术,目前国内尚无脱硫系统除雾器性能测试统一标准规范。介绍了氨法烟气脱硫系统雾滴浓度的测定方法———硫酸根离子法,阐述了该方法的原理与特点,方法步骤,为氨法烟气脱硫工程考核除雾器性能提供了一种有效的参考方法。 相似文献
496.
497.
TGM measurements on board ships have proved to provide valuable complementary information to measurements by a ground based monitoring network. During the third China Arctic Research Expedition (from July 11 to September 24, 2008), TGM concentrations over the marine boundary layer along the cruise path were in-situ measured using an automatic mercury vapor analyzer. Here we firstly reported the results in Japan Sea, North Western Pacific Ocean and Bering Sea, where there are rare reports. The value ranged between 0.30 and 6.02 ng/m3 with an average of (1.52 ± 0.68) ng/m3, being slightly lower than the background value of Northern Hemisphere (1.7 ng/m3). Notably TGM showed considerably spatial and temporal variation. Geographically, the average value of TGM in Bering Sea was higher than those observed in Japan Sea and North Western Pacific Ocean. In the north of Japan Sea TGM levels were found to be lower than 0.5 ng/m3 during forward cruise and displayed obviously diurnal cycle, indicating potential oxidation of gaseous mercury in the atmosphere. The pronounced episode was recorded as well. Enhanced levels of TGM were observed in the coastal regions of southern Japan Sea during backward cruise due primarily to air masses transported from the adjacent mainland reflecting the contribution from anthropogenic sources. When ship returned back and passed through Kamchatka Peninsula TGM increased by the potential contamination from volcano emissions. 相似文献
498.
环境保护是我国的一项基本国策,交通建设尤其是公路建设项目的环境问题是环境保护工作的重要组成部分。做好公路建设中环境保护工作,是实现公路建设与经济、社会及环境的协调发展的必由之路。本文就道路交通建设中的环境保护与环境监测工作做以论述,并就公路环境保护工作提出展望,以期早日实现基于可持续发展理念下的现代绿色环保交通。 相似文献
499.
Robert K. Dixon Xi Wang Michael Q. Wang Ju Wang Zhihong Zhang 《Mitigation and Adaptation Strategies for Global Change》2011,16(7):775-789
The demand for urban transportation in China, including cars, motorbikes, buses, and trains, is growing substantially. China’s
transportation fleet is projected to expand from 16 to 94 million vehicles between 2000 and 2020, with liquid and electricity
transport fuel demand growing from about 5 Quadrillion British Thermal Units (Quads) to over 20 Quads in 2035. In response
to energy security, economic growth and environmental protection needs, Chinese government agencies, academia and the private
sector have organized their programs and investments to advance development and demonstration of sustainable alternative transportation
systems. This analysis surveys historic development of fuel cell vehicle (FCV) including fuel cell buses (FCB) technology
in China, summarizes recent efforts to scale-up FCV development and associated infrastructure in major Chinese cities, and
briefly addresses future directions in Chinese fuel cell and hydrogen energy technology development. Since the late 1990’s,
Chinese universities, government institutions and the private sector have implemented research, development, demonstration
and deployment programs for electric (EV), fuel cell (FCV), and hybrid electric vehicles (HEV). These efforts have advanced
the feasibility of FCVs to be a part of sustainable urban transportation system, including technical performance, infrastructure,
and customer acceptance. Three generations of FCVs, START I, START II and START III have been developed, demonstrated and
deployed. Similarly, several generations of FCBs have been developed and demonstrated. Collectively, these efforts have demonstrated
and deployed over 1,000 FCBs and FCVs in several Chinese cities. Large-scale, intensive-use FCV and FCB demonstration trials,
including those during the 2008 Beijing Olympics and the 2010 Shanghai World Exposition (EXPO), have been successfully built
and operated. Infrastructure, such as hydrogen production facilities, fuelling stations, and maintenance stations have been
constructed and operated to support the fleets of FCBs and FCVs. Experiences learned from these FCV research, development,
and demonstration activities are the foundation for scaling up infrastructure and fleet trials in a growing number of cities
in eastern and western China. An aggressive research and development vision and 2020 technology performance targets provide
a foundation for the next generation of EVs, FCVs and HEVs, and, options for China’s efforts to develop a portfolio of sustainable
transportation systems. 相似文献
500.
本文以嘉山台地电阻率数字化改造后的观测资料为基础,在台址条件、资料质量、干扰因素等方面进行了较为系统的整理,总结了地电阻率观测中的非震现象、典型干扰的变化及影响观测精度的因素,对干扰机制也进行了必要的判断,同时对嘉山台地电阻率的映震效能进行了尝试性的分析,为同类型地电台有效地识别和排除干扰提供参考和借鉴。 相似文献