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301.
2004年,国家安全监管局印发了《关于开展安全质量标准化活动的指导意见》,煤矿、非煤矿山、危险化学品、烟花爆竹、冶金、机械等行业均 相似文献
302.
以虚拟区域和哈尔滨市道里区经纬街为研究区,以满足居民避难需求为目标,分别构建居民避难行动效率模型与应急避难所服务范围模型,并将二者进行耦合。先以虚拟区域说明利用耦合模型的适用性与可行性,再以研究区探讨居民避难所效率与应急避难所优化配置。研究结果表明:研究区现状应急避难所配置,在研究区有2处是应急避难所服务无法覆盖的范围。以耦合模型为基础,确定需要增加2个应急避难所,才能满足居民避难需求。该研究方法不仅为我国应急避难所优化配置理论与方法作了补充,其结果也为研究区及其他地区应急避难所优化配置提供了参考依据。 相似文献
303.
Mao Xinyou Wang Lan Gu Shiqing Duan Yanyan Zhu Yunqing Wang Chuanyi Lichtfouse Eric 《Environmental Chemistry Letters》2018,16(2):653-658
Environmental Chemistry Letters - Water pollution caused by heavy metals has dramatically impacted ecosystems in recent years. For instance, 45.4% of lakes in China are in the category of moderate... 相似文献
304.
为研究套箍法加固RC偏压柱的承载力实用计算方法,利用29根加固柱的试验资料,对《混凝土结构加固设计规范》GB 50367—2013和GB 50367—2006的承载力计算方法进行了研究,将试件承载力计算值与实测值进行对比发现,两部规范的承载力计算结果比较接近,计算结果的整体准确性都不够好、偏于不安全,尤其对大偏压柱的承载力计算较为不安全。根据加固柱的受力破坏特性,定义了3种破坏极限状态,基于3种极限状态下的截面应变分布分析,建立了加固柱的承载力计算公式,验证表明,该公式的计算结果与试验结果吻合较好,且偏于安全。 相似文献
305.
静电纺壳聚糖/聚乙烯醇纳米纤维膜对Cu~(2+)、Ni~(2+)及Cd~(2+)的吸附特性 总被引:3,自引:3,他引:0
采用SEM、FTIR、XRD、BET等技术对静电纺丝制得的吸附材料壳聚糖/聚乙烯醇(CS/PVA)纳米纤维膜进行表征,并通过对模拟重金属离子废水的吸附实验,系统考察了溶液pH、重金属离子(Cu2+、Ni2+及Cd2+)初始浓度和反应温度对吸附的影响.结果表明,在外加电压25kV、接触距离15.0 cm、纺丝速度0.15 m L·h-1的条件下,可制得CS/PVA质量比为20/80的连续无缺陷的平均直径76.31 nm、比表面积219.4m2·g-1的纤维膜.CS/PVA纳米纤维膜对重金属离子的吸附在2 h内达到平衡,其吸附容量随着温度的升高而升高,随着初始浓度的增大而增大,随着pH值的升高而提高,在pH=5.5时达到最大.在25℃和pH=5.5的条件下,用CS/PVA纳米纤维膜吸附浓度100 mg·L-1的Cu2+、Ni2+和Cd2+溶液,吸附容量分别为98.65、116.89和124.23 mg·g-1,且对重金属吸附无选择性.吸附过程符合Langmuir和Freundlich等温吸附模型,吸附动力学同时匹配准一级动力学模型和准二级动力学模型.热力学参数(ΔG、ΔH和ΔS)计算结果表明,CS/PVA纳米纤维膜对重金属离子的吸附是自发的吸热反应. 相似文献
306.
Jianhua Wang Yizi Shang Hao Wang Yong Zhao Yin Yin 《Journal of the American Water Resources Association》2015,51(3):614-623
Beijing's local water resources have been overexploited and the ecological and environmental pressures exceed the carrying capacity of this densely populated megacity. This article examines the current status of Beijing's water resources with respect to its industrial, residential, and eco‐environmental water usage and the challenges it may face in the near future. The article describes the context of water uses, the steps taken by Beijing to alleviate the water shortage problems, and challenges to Beijing's abilities to meet its urgent and future water needs. A multipronged strategy is proposed that aims at both the present problems and the anticipated future challenges. In particular, engineering and institutional approaches for Beijing's successful transition from overexploitation to sustainable utilization of water resources are explained. Actions include reasonable water utilization, water conservation, reclaimed wastewater, and importing water from neighboring areas. We conclude that Beijing must take additional steps in water resource management to ensure its sustainable development that involves continued urbanization sprawls and population growth. Future water resource management strategies should focus on strengthening water demand management through water conservation, efficient interbasin water transfers, use of nontraditional water resources, strategically reserving water supply, and promoting rehabilitation of the eco‐environments. 相似文献
307.
采用液液萃取和固相萃取前处理方法与气相色谱—质谱联用技术相结合对扎龙底泥中7种多氯联苯进行测定。该方法操作简便、快速、重现性好、精密度高、检出限低,结果令人满意。 相似文献
308.
We investigated the efficiency and kinetics of the degradation of soluble dyes over the p H range 5.0–9.0 using a method employing microwave radiation in combination with nanoscale zero-valent iron(MW–n ZVI). The n ZVI particles(40–70 nm in diameter) were prepared by a liquid-phase chemical reduction method employing starch as a dispersant.Compared to the removal of Solvent Blue 36 and Reactive Yellow K-RN using only n ZVI,more rapid and efficient dye removal and total organic carbon removal were achieved using MW–n ZVI. The dye removal efficiency increased significantly with decreasing p H, but was negligibly affected by variation in the microwave power. The kinetics of dye removal by MW–n ZVI followed both an empirical equation and the pseudo first-order model, while the kinetics of dye removal using n ZVI could only be described by an empirical equation. It was also concluded that microwave heating of the dye solutions as well as acceleration of corrosion of n ZVI and consumption of Fe(II) were possible reasons behind the enhanced dye degradation. 相似文献
309.
Photodegradation(PD) of methylmercury(MMHg) is a key process of mercury(Hg) cycling i water systems, maintaining MMHg at a low level in water systems. However, we posses little knowledge of this important process in the Jialing River of Chongqing, China. In sit incubation experiments were thus performed to measure temporal patterns and influencin factors of MMHg PD in this river. The results showed that MMHg underwent a ne demethylation process under solar radiation in the water column, which predominantl occurred in surface waters. For surface water, the highest PD rate constants were observed i spring(12 × 10-3± 1.5 × 10~(-3)m~2/E), followed by summer(9.0 × 10~(-3)± 1.2 × 10~(-3)m~2/E), autum(1.4 × 10~(-3)± 0.12 × 10~(-3)m~2/E), and winter(0.78 × 10~(-3)± 0.11 × 10~(-3)m~2/E). UV-A radiatio(320–400 nm), UV-B radiation(280–320 nm), and photosynthetically active radiation(PAR400–700 nm) accounted for 43%–64%, 14%–31%, and 16%–45% of MMHg PD, respectively. PD rat constants varied substantially with the treatments that filtered the river water and amended with chemicals(i.e., Cl-, NO_3~-, dissolved organic matter(DOM), Fe(III)), which reveals tha suspended particulate matter and water components are important factors in affecting the PD process. For the entire water column, the PD rate constant determined for each wavelengt range decreased rapidly with water depth. UV-A, UV-B, and PAR contributed 27%–46%, 6.2%12%, and 42%–65% to the PD process, respectively. PD flux was estimated to be 4.7 μg/(m~2·yea in the study site. Our results are very important to understand the cycling characteristics o MMHg in the Jialing River of Chongqing, China. 相似文献
310.
在依据出口能力不同对中国工业行业进行分类的基础上,利用灰色关联分析,定量比较了出口能力不同工业行业对环境污染的影响差异;通过构造环境影响系数,分析了依出口能力差异划分的工业结构变动对环境污染的影响趋势。研究表明,中国出口能力强的工业行业对环境污染影响较大,目前的工业行业出口能力结构变动趋势对环境污染有减轻迹象,适度降低工业行业结构中出口能力强行业的比重,有助于减轻中国环境污染压力。 相似文献