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排序方式： 共有3986条查询结果，搜索用时 15 毫秒
1.
针对辽宁省菱镁矿区资源状况与环境问题,提出菱镁矿区土地生态修复技术对策,包括土壤污染等级分类对策、不同立地条件土地复垦适宜性评价与对策、板结土壤复垦技术与对策和排土场贫瘠土壤肥力改良修复对策,进行适宜性复垦植物筛选与复垦效果评价。 相似文献
2.
维持经济的持续稳定增长是我国的重要政策目标,然而面对日趋严峻的资源、环境制约,大力推进生态文明建设已刻不容缓。相应地,在理论方面,研究经济增长与环境污染的双向作用机制也非常必要。利用VAR模型,研究了辽宁省经济发展与环境之间的关系,发现两者之间的关系并不是EKC理论中所说的倒u型曲线,而是呈现w型、N型等更加复杂的曲线形状。实验结果也表明辽宁省环境与经济存在双向作用机制,其中,废气与废水对辽宁省经济增长影响最大。 相似文献
3.
针对城市热岛效应引起城区浅层土地温场升高这一观测结果,采用室内快速模拟试验方法,对城区酸性土壤腐蚀混凝土材料的温度效应开展了试验研究.试验研究了在温度为5℃、20℃和40℃条件下,混凝土试样在酸浓度分别为0%、5%和10%的沙土介质中放置30 d、90 d后的抗压强度变化规律,并对混凝土试样在腐蚀过程中的腐蚀系数变化规... 相似文献
4.
Chung-Ming Liu 《Chemistry and Ecology》1996,12(1):147-161
In this paper, three sensitivity studies are designed to analyze the effect of the NMHC (Non-Methane HydroCarbon) composition, the aerosol back-scattering and the high chimney NOx emission to the photochemical prodution of ozone by using a one-dimensional photochemistry-diffusion model under a favourable meteorological condition. Measurements of the NMHC composition in Taipei indicated that the percentage of iso-butene, cis-2-butene, trans-2-butene and benzene in a unit volume was much higher than of those observed in other major cities. the high ratio of benzene was directly linked to its high percentage in gasoline. As to the unusually high amount of iso-butene, cis-2-butene and trans-2-butene, more researches are needed to identify their source. Concerns are raised as to how productive is NMHC composition is to the photochemical production of the surface ozone. A rough estimate shows that the total reactivity of the Taipei NMHC composition is about 1.21 × 10-9 cm3 s-1 which is 1.6 times that of the Los Angeles (LA) NMHC composition, while the simulated noon peak will be different by 28 ppbv, i.e. 18% more than that simulated with a LA composition.
Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.
In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NOx from high chimneys cannot be ignored. in this study, NOx is assumed to be emitted in the layer between 235-460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NOx emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated. 相似文献
Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.
In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NOx from high chimneys cannot be ignored. in this study, NOx is assumed to be emitted in the layer between 235-460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NOx emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated. 相似文献
5.
Introduction: Driving under the influence (DUI) increases the probability of motor-vehicle collisions, especially for motorcycles with less protections. This study aimed to identify commonalities and differences between criminally DUI offenses (i.e., with a blood alcohol concentration (BAC) of 80 mg/dL or higher) committed by motorcyclists and car drivers. Methods: A total of 10,457 motorcycle DUIs and 8,402 car DUIs were compared using a series of logistic regression models, using data extracted from the documents of adjudication decisions by the courts of Jiangsu, China. Results: The results revealed that offenders from the high-BAC group (i.e., 200 mg/dL or higher) accounted for more than 20% of the total DUI offenses, and were more likely to be involved in a crash and punished with a longer detention. Motorcyclists had a higher likelihood of crash involvement, and were also more likely to be responsible for single-vehicle crashes associated with higher odds of injury sustained, compared to alcohol-impaired car drivers. In the verdict, motorcycle offenders were more likely to receive a less severe penalty. Conclusions: Interventions are clearly required to focus on reducing in the high-BAC group of offenders. For alcohol-impaired motorcyclists, their risks of crash and injury against BAC climb more steeply than the risks for car drivers. The factors including frequent occurrences, uncertainty of detection, and short-term sentences may weaken the deterrence effect of the criminalization of motorcycle DUI. Practical Applications: The traffic-related adjudication data support traffic safety analysis. Strategies such as combating motorcycle violations (e.g., unlicensed operators or driving unsafe vehicles), undertaking education and awareness campaigns, are expected for DUI prevention. 相似文献
6.
密闭爆炸容器实验研究及数值模拟 总被引：7，自引：0，他引：7
实验研究了三种结构的爆炸容器在爆炸载荷下的响应情况；并通过二维多流体欧拉程序对二维爆炸场进行了数值模拟．在这个基础上用ＮＩＫＥ－２Ｄ对壳体的动态响应进行数值模拟。 相似文献
7.
以氨氧化细菌—欧洲亚硝化单胞杆菌(Nitrosomonas europaea)为模式菌株,研究纳米银(silver nanoparticles,AgNPs)在不同离子强度水样中的赋存形态及对N.europaea氧化NH4+-N性能的影响。在N. europaea培养液、月牙湖水、生活污水、化工废水4种水样中分别添加AgNPs及不同形态Ag化合物,测试其对N.europaea的急性毒性,得到AgNPs及不同形态银对N.europaea的毒性效应浓度EC20、EC50和EC80。采用紫外可见吸收光谱法分析AgNPs在不同离子强度水样中的粒径变化。利用Visual MINTEQ模型预测AgNPs在4种水样中的主要化学形态分布,发现水样的离子组分及离子强度显著影响AgNPs的聚集和Ag的赋存状态。在4种水样中分别添加不同浓度(EC20、EC50和EC80)的AgNPs,探究不同离子强度水样中的AgNPs对N.europaea活性的影响,结果表明随着水样中外源添加AgNPs浓度的增加,N.europaea氧化NH4+-N的效率降低,特别在培养液和校园生活污水中,呈现较明显的剂量效应;但在月牙湖水和化工废水中,由于其含有高浓度SO42−、Cl−等离子组分,影响AgNPs对N.europaea的毒性效应。评价AgNPs在环境水体或污水中的生物毒性,应考虑水中离子组成和离子强度对其毒性的影响。 相似文献
8.
化石燃料燃烧产生的温室气体与大气污染物具有同根同源性,但具体治理中减污降碳的协同效果尚不明确。以浙江省11个设区市为研究样本,对环境空气质量和二氧化碳(CO2)排放数据进行分析研究,结果显示：2016—2020年浙江省环境空气质量持续改善,但CO2排放总量仍处于增长阶段。11个设区城市PM2.5年均浓度降幅在26%～41%之间,二氧化氮(NO2)年均浓度下降趋势不明显,大部分城市呈现碳排放增加、NO2浓度下降的特征,只有杭州和温州两市呈现碳排放总量和NO2、PM2.5浓度协同下降的趋势。因子相关性分析结果表明,各设区市呈现NO2浓度与碳排放相关性较大、协同性强,PM2.5浓度与碳排放相关性较小的特点。进一步通过减污降碳协同定量评价分析表明,浙江地区在环境空气质量改善和温室气体减排已表现出一定成效,但各设区市因产业结构、环境基础条件、协同程度等不同导致减污降碳综合绩效有明显差异。从源头减排实现... 相似文献
9.
Yuchen Gao Jianguo Jiang Yuan Meng Tongyao Ju Siyu Han 《Frontiers of Environmental Science & Engineering》2023,17(3):32
10.
Han Qu Hongting Diao Jiajun Han Bin Wang Gang Yu 《Frontiers of Environmental Science & Engineering》2023,17(1):12
Over the past decades, the plastic production has been dramatically increased. Indeed, a category of small plastic particles mainly with the shapes of fragments, fibers, or spheres, called microplastics (particles smaller than 5 mm) and nanoplastics (particles smaller than 1 μm) have attracted particular attention. Because of its wide distribution in the environment and potential adverse effects to animal and human, microplastic pollution has been reported as a serious environment problem receiving increased attention in recent years. As one of the commonly detected emerging contaminants in the environment, recent evidence indicates that the concentration of microplastics show an increasing trend, for the reason that up to 12.7 million metric tons of plastic litter is released into aquatic environment from land-based sources each year. Furthermore, microplastic exposure levels of model organisms in laboratory studies are usually several orders of magnitude higher than those found in environment, and the microplastics exposure conditions are also different with those observed in the environment. Additionally, the detection of microplastics in feces indicates that they can be excreted out of the bodies of animal and human. Hence, great uncertainties might exist in microplastics exposure and health risk assessment based on current studies, which might be exaggerated. Policies reduce microplastic emission sources and hence minimize their environmental risks are determined. To promote the above policies, we must first overcome the technical obstacles of detecting microplastics in various samples. 相似文献