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61.
哈尔滨市区绿地对交通噪声衰减效果研究   总被引:1,自引:0,他引:1  
2007年4月6日-5月30日,采用HS-5633型数字声级仪分别对哈尔滨市区六处主要交通干道进行交通噪声测量,同时在干道周围的绿地进行对比测量,并将所得数据进行分析统计。结果表明,绿地(包括各类林地、草坪、隔离带及其不同组合)对交通噪声的衰减可达2dB(A)以上,减噪效果十分明显,减噪数值与绿地宽度和绿地植被组成有密切关系。因此,应对城市中各种类型的绿地及其组成的混合林地种植予以足够、有效的重视,如高大乔木+灌木、常绿树+草坪、乔木+灌木+草坪等配置紧凑的绿地类型,并应加大保护力度。  相似文献   
62.
丁佳  周华 《环境科学与管理》2011,36(9):113-117,141
HACH光度法测定CODcr优势在于操作简便、试剂成本低、能批量分析等,但消解时间与国标法一致,仍为2 h。本实验根据废水组分的不同,缩短消解时间,从而快速、准确测定CODcr。结果表明:印染废水消解时间为20 min;化工、生活废水消解时间同为60 min;医药废水消解时间则为80 min。上述消解时间测定的样品,其准确度、精密度、加标回收率均达到质控要求。通过本方法与国标法比对试验表明,两种方法测定结果无显著性差异,因此可在实际工作中借鉴并推广。  相似文献   
63.
废旧手机电池进行人工拆解后,将正极浸入N-甲基吡咯烷酮(NMP)中,使正极活性物质与铝箔分离.再利用酸浸-碱出方法回收正极活性物质中的钴和锂.确定最佳工艺参数为:0.8 molg·L-1的硫酸溶液,反应温度50℃,固液比1∶20g· L-1,水浴加热60 min.用饱和Na2CO3溶液沉淀锂得到Li2CO3,NaOH溶液将钴沉淀,400℃煅烧3h得到Co3 O4.按化学计量比将Co3O4与Li2CO3混合,预处理后700℃煅烧7h得到LiCoO2粉末.对再生的LiCoO2进行了结构和形貌测试,表明再生后生成了颗粒均匀、结晶度较好的LiCoO2.  相似文献   
64.
The impacts of climate change on potential rice production in Asia are reviewed in the light of the adaptation to climatic variability and change. Collaborative studies carried out by IRRI and US-EPA reported that using process-based crop simulation models increasing temperature may decrease rice potential yield up to 7.4% per degree increment of temperature. When climate scenarios predicted by GCMs were applied it was demonstrated that rice production in Asia may decline by 3.8% under the climates of the next century. Moreover, changes in rainfall pattern and distribution were also found suggesting the possible shift of agricultural lands in the region. The studies however have not taken the impacts of climatic variability into account, which often produce extreme events like that caused by monsoons and El Niño. Shifts in rice-growing areas are likely to be constrained by land-use changes occurring for other developmental reasons, which may force greater cultivation of marginal lands and further deforestation. This should be taken into account and lead to more integrated assessment, especially in developing countries where land-use change is more a top-down policy rather than farmers' decision. A key question is: To what extent will improving the ability of societies to cope with current climatic variability through changing design of agricultural systems and practices help the same societies cope with the likely changes in climate?  相似文献   
65.
在工业废油污染程度综合评价研究中,各类复杂油质和众多影响因素相互作用,各个理化指标间相互联系、相互干扰,因而在评价中存在一些模糊的概念和表象。采用熵权法客观赋权,灰色关联与模糊综合评价相结合的方法建立工业废油污染程度的评价排序模型。根据算例评价结果可知,该方法提供一种新的简便而快捷、适用的评价手段,为选择合适工业废油处理方式,以及工业废油的资源化和环境保护研究提供一定的理论依据。  相似文献   
66.
对某钢厂康斯迪电炉爆炸事故现场进行了调查,分析了引起电炉爆炸的原因,得出该事故是由于废钢铁中混有爆炸性物质的结论,提出钢厂对回炉熔炼用的废钢铁要严格分类、筛选,防止此类事故再次发生.  相似文献   
67.
矿山废弃地的生态恢复   总被引:27,自引:0,他引:27  
本文通过对矿山废弃地及其恢复情况调查,分析了我国矿山废弃地生态恢复的方向及蕴藏的产业机遇。  相似文献   
68.
Effective conservation of biological diversity on private lands will require changes in land‐use policy and development practice. Conservation development (CD) is an alternative form of residential development in which homes are built on smaller lots and clustered together and the remainder of the property is permanently protected for conservation purposes. We assessed the degree to which CD is permitted and encouraged by local land‐use regulations in 414 counties in the western United States. Thirty‐two percent of local planning jurisdictions have adopted CD ordinances, mostly within the past 10 years. CD ordinances were adopted in counties with human population densities that were 3.0 times greater and in counties with 2.5 times more land use at urban, suburban, and exurban densities than counties without CD ordinances. Despite strong economic incentives for CD (e.g., density bonuses, which allow for a mean of 66% more homes to be built per subdivision area), several issues may limit the effectiveness of CD for biological diversity conservation. Although most CD ordinances required a greater proportion of the site area be protected than in a typical residential development, just 13% (n = 17) of the ordinances required an ecological site analysis to identify and map features that should be protected. Few CD ordinances provided guidelines regarding the design and configuration of the protected lands, including specifying a minimum size for protected land parcels or encouraging contiguity with other protected lands within or near to the site. Eight percent (n =11) of CD ordinances encouraged consultation with a biological expert or compliance with a conservation plan. We recommend that conservation scientists help to improve the effectiveness of CD by educating planning staff and government officials regarding biological diversity conservation, volunteering for their local planning boards, or consulting on development reviews. Guías e Incentivos para el Desarrollo de la Conservación en Regulaciones de Uso Local de Suelos  相似文献   
69.
Studies on the vegetation and soil complexes in areas of the Kolyma River basin disturbed by mining, in the northeast of the Chukchi Peninsula, have been performed to reveal trends in natural restorative processes in posttechnogenic landscapes. Data on the flora, phytomass stock, chemical composition of plants pioneering in the overgrowing of disturbed areas, and physicochemical properties of soils and technogenic eluvia have been obtained. The results have shown that plant cover restoration in disturbed areas depends primarily on the type (genesis) of technogenic substrates, the content of fine earth in the surface layer, and the distance from natural plant complexes that serve as a source of seeds coming to the disturbed area.  相似文献   
70.
While there are increasing numbers of non-consumptive forest uses on public lands, some silvicultural management systems provide little flexibility for the realization of non-commodity values. Traditional economic decision-making tools, such as net present value, are often applied in a manner which inadequately accounts for the full value of the resource. As a result, sub-optimal management practices are often implemented. By applying a marginal analysis of the optimal externality of different silvicultural systems, it is possible to identify the optimal timber management strategy in terms of the total costs of the timber harvest under alternative uses. Although difficulties arise in valuing non-consumptive uses, contingent valuation with averting costs estimates can establish a lower bound on society's willingness to pay for foregone timber harvesting. Low impact harvest operations and “new forestry” techniques, such as selection harvest cuts, are helpful in reducing the external costs of timber cutting. Therefore, the implementation of such systems may actually increase the socially optimal area of public lands to be harvested under a multiple-use designation.  相似文献   
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