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31.
自然资源资产仍然是一个新概念,还需要在理论和方法层面进行系统的研究。就当今及今后一个时期看,自然资源资产负债表的编制和自然资源资产审计,是亟需研究的理论和现实问题。在此,重点对自然资源资产的概念、属性、分类进行探讨,并就自然资源资产负债表及编制的重点与基础,自然资源资产审计及其重点与方式等,进行系统讨论。  相似文献   
32.
光污染已经成为继水污染、大气污染、噪声污染、固体废物污染之后的第五大污染.是21世纪直接影响人类健康的又一环境杀手!  相似文献   
33.
城市控制爆破工程的爆破事故和爆破公害研究   总被引:4,自引:5,他引:4  
爆破事故和爆破公害是关于爆破工程中的安全问题,笔者对爆破事故中的早爆、拒爆和爆破公害中的爆破振动、爆破空气冲击波、爆破飞石进行了详细论述,分析了爆破事故及公害产生的原因,从而给出了相应的防止措施;进而依法采取了爆破安全管理可行办法.  相似文献   
34.
Prediction of the Fate and Transport Processes of Atrazine in a Reservoir   总被引:1,自引:0,他引:1  
The fate and transport processes of a toxic chemical such as atrazine, an herbicide, in a reservoir are significantly influenced by hydrodynamic regimes of the reservoir. The two-dimensional (2D) laterally-integrated hydrodynamics and mass transport model, CE-QUAL-W2, was enhanced by incorporating a submodel for toxic contaminants and applied to Saylorville Reservoir, Iowa. The submodel describes the physical, chemical, and biological processes and predicts unsteady vertical and longitudinal distributions of a toxic chemical. The simulation results from the enhanced 2D reservoir model were validated by measured temperatures and atrazine concentrations in the reservoir. Although a strong thermal stratification was not identified from both observed and predicted water temperatures, the spatial variation of atrazine concentrations was largely affected by seasonal flow circulation patterns in the reservoir. In particular, the results showed the effect of flow circulation on spatial distribution of atrazine during summer months as the river flow formed an underflow within the reservoir and resulted in greater concentrations near the surface of the reservoir. Atrazine concentrations in the reservoir peaked around the end of May and early June. A good agreement between predicted and observed times and magnitudes of peak concentrations was obtained. The use of time-variable decay rates of atrazine led to more accurate prediction of atrazine concentrations, while the use of a constant half-life (60 days) over the entire period resulted in a 40% overestimation of peak concentrations. The results provide a better understanding of the fate and transport of atrazine in the reservoir and information useful in the development of reservoir operation strategies with respect to timing, amount, and depth of withdrawal.  相似文献   
35.
芳香烃清洁硝化催化剂   总被引:2,自引:0,他引:2  
综述了国内外有关芳香烃硝化过程中替代硫酸的催化剂的研究进展;介绍了沸石类催化剂、粘土类催化剂、离子交换树脂催化剂、固载化液体酸催化剂、金属氧化物及金属盐催化剂、杂多酸催化剂以及固体超强酸催化剂的合成及催化效率与优缺点.  相似文献   
36.
用次氯酸钠法处理选矿废水   总被引:2,自引:0,他引:2  
采用次氯酸钠法处理铅锌硫化矿选矿废水,考察了废水初始pH、NaClO加入量及反应时间对选矿废水COD去除率的影响。在废水pH为4、NaClO加入量为100g/L、反应时间为30min的条件下,选矿废水的COD去除率可达到98.3%;当pH为11、反应时间为10min、NaClO加入量为1g/L时,选矿废水的COD去除率为39.4%。  相似文献   
37.
  总被引:1,自引:0,他引:1  
In recent years several types of sensors and measurement techniques have been developed for measuring the moisture content, water saturation, or the volumetric water content of landfilled wastes. In this work, we review several of the most promising techniques. The basic principles behind each technique are discussed and field applications of the techniques are presented, including cost estimates. For several sensors, previously unpublished data are given. Neutron probes, electrical resistivity (impedance) sensors, time domain reflectometry (TDR) sensors, and the partitioning gas tracer technique (PGTT) were field tested with results compared to gravimetric measurements or estimates of the volumetric water content or moisture content. Neutron probes were not able to accurately measure the volumetric water content, but could track changes in moisture conditions. Electrical resistivity and TDR sensors tended to provide biased estimates, with instrument-determined moisture contents larger than independent estimates. While the PGTT resulted in relatively accurate measurements, electrical resistivity and TDR sensors provide more rapid results and are better suited for tracking infiltration fronts. Fiber optic sensors and electrical resistivity tomography hold promise for measuring water distributions in situ, particularly during infiltration events, but have not been tested with independent measurements to quantify their accuracy. Additional work is recommended to advance the development of some of these instruments and to acquire an improved understanding of liquid movement in landfills by application of the most promising techniques in the field.  相似文献   
38.
A comparative study on Fe/Al, Fe/Al/Cu, and Fe/Al/Ni catalysts in high-temperature water–gas shift reaction (HT–WGS) using simulated waste-derived synthesis gas has been carried out. The metal oxide (Cu and Ni) and aluminum incorporated Fe catalysts were designed to get highly active HT–WGS catalysts. Despite the high CO concentration in the simulated waste-derived synthesis gas, Fe/Al/Cu catalyst exhibited the highest CO conversion (84 %) and 100 % selectivity to CO2 at a very high gas hourly space velocity (GHSV) of 40,057 h?1. The outstanding catalytic performance is mainly due to easier reducibility, the synergy effect of Cu and Al, and the stability of the magnetite.  相似文献   
39.
在N2保护下,以硝硬驱铈铵为引发剂,将壳聚糖(CTS)、丙烯酰胺(AM)及二甲基二烯丙基氯化铵(DMDAAC)接枝共聚得到CTS-AM-DMDAAC三元接枝共聚物,考察了反应条件对接枝共聚反应的影响。实验结果表明,在反应温度50℃、反应时间5-6h,m(CTS):m(AM):m(DMAAAC)=1:6:0.67、c(Ce^4+)=0.8mmol/L的最佳反应条件下,接枝共聚反应的接枝率和接枝效率分别为64%和10.5%。用傅里叶变换红外光谱仪对CTS-AM-DMDAAC进行了表征。絮凝实验结果表明:CTS-AM-DMDAAC对高岭土水样具有较强的絮凝能力,可在很宽的pH范围内使用。用CTS-AM-DMDAAC处理COD为165.5mg/L的啤酒生产废水,COD去除率达90.1%.  相似文献   
40.
    
A growing number of firms are realizing that entrepreneurial orientation (EO) is an effective means to cope with competition and maintain sustainable growth. However, with the results of extant studies on EO-performance relationship are not fully consistent, the potential mechanism about how EO influences firm performance needs to be further explored. Accordingly, this research investigates the mediating mechanism of EO-performance by considering the role of corporate social responsibility (CSR) from the resource dependence perspective. In addition, we assess the relationship between EO and CSR by examining the moderating roles of institutional support and dysfunctional competition. Using the sample data of 214 Chinese firms to test the hypotheses, we find that CSR mediates the relationship between EO and firm performance. Moreover, institutional support negatively moderates the EO-CSR relationship and dysfunctional competition positively moderates the relationship between EO and CSR. Based on the above results, our study provides practical implications for entrepreneurial firms striving to translate their EO into superior firm performance.  相似文献   
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