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81.
以业已建成的稻麦作物净初级生产力模型为基本框架,建立了一个具有普适性的中国农业植被净初级生产力模型(CropC-)。CropC-的模拟对象为占我国农作物总播种面积2/3的水稻、小麦、玉米、棉花、油菜和大豆。该模型包括2个主要功能模块:光合作用和呼吸作用;土壤-作物系统氮素运移。前者综合考虑了环境因子和氮素的影响,后者包括了作物氮素吸收、土壤氮矿化和化肥氮释放。灵敏度分析表明,在输入参数变化±10%时,CropC-对6个主要输入参数响应的敏感性依次为温度>光合有效辐射>大气CO2浓度>土壤全氮含量>施氮量>降水。模型分析表明,气候变暖将降低作物净初级生产力。  相似文献   
82.
牙鲆、孔石莼分泌物对混合重金属在牙鲆组织蓄积的影响   总被引:1,自引:0,他引:1  
研究了海水中总有机碳(TOC)浓度、总有机碳种类对混合重金属(Cu Pb、Cu Cd、Cu Pb Cd)在牙鲆(Paralichthys olivaceus)内脏、肌肉、鳃组织蓄积的影响.结果表明,孔石莼分泌物、牙鲆分泌物均能降低Cu、Pb、Cd的生物有效性;当海水TOC种类相同时,随TOC浓度的升高,牙鲆的内脏、肌肉、鳃组织中Cu、Pb、Cd蓄积量均明显下降;当海水TOC浓度相近时,孔石莼分泌物比牙鲆分泌物更能降低牙鲆各组织Cu、Pb、Cd蓄积量.TOC浓度、种类的变化对牙鲆各组织中Cu、Pb、Cd蓄积分配均无影响,各组织重金属蓄积量顺序均为:内脏>鳃>肌肉.  相似文献   
83.
The Lawrence Berkeley National Laboratory (Berkeley Lab) and the Center for Sustainable Development in the Americas (CSDA) conducted technical studies and organized two training workshops to develop capacity in Central America for the evaluation of climate change projects. This paper describes the results of two baseline case studies conducted for these workshops, one for the power sector and one for the cement industry, that were devised to illustrate certain approaches to baseline setting. Multiproject baseline emission rates (BERs) for the main Guatemalan electricity grid were calculated from 2001 data. In recent years, the Guatemalan power sector has experienced rapid growth; thus, a sufficient number of new plants have been built to estimate viable BERs. We found that BERs for baseload plants offsetting additional baseload capacity ranged from 0.702 kgCO2/kWh (using a weighted average stringency) to 0.507 kgCO2/kWh (using a 10th percentile stringency), while the baseline for plants offsetting load-following capacity is lower at 0.567 kgCO2/kWh. For power displaced from existing load-following plants, the rate is higher, 0.735 kgCO2/kWh, as a result of the age of some plants used for meeting peak loads and the infrequency of their use. The approved consolidated methodology for the Clean Development Mechanism yields a single rate of 0.753 kgCO2/kWh. Due to the relatively small number of cement plants in the region and the regional nature of the cement market, all of Central America was chosen as the geographic boundary for setting cement industry BERs. Unfortunately, actual operations and output data were unobtainable for most of the plants in the region, and many data were estimated. Cement industry BERs ranged from 205 kgCO2 to 225 kgCO2 per metric ton of cement.  相似文献   
84.
Population demography, seed production, biomassallocation, net photosynthesis and transpiration of two Leymus chinensis divergence populations and between two years in Songnenplain, northeast China were compared. Strong differences betweenthe dry 1997 and moist 1998 occurred in vegetative shoot and sexualshoot densities, sexual differentiation and tiller densities, aswell as in the lengths of inflorescence, seed numbers perinflorescence, seed weights and biomass allocation in eachpopulation respectively (P<0.01). While strong differences betweenthe two populations occurred in vegetative shoot densities, sexualshoot densities, sexual differentiation and seed weights in eachyear (P<0.01). The differences between the two populations intiller densities and in biomass allocation to sexual shoots were significant (P<0.05). But there were no significant differences between the two populations in the lengths of inflorescence, seed numbers per inflorescence and biomass allocation to rhizomes and vegetative shoots (P>0.05). Excepting the transpiration rate in the early June, the differences between the two populations in net photosynthesis and transpiration rate of vegetative shoots and sexual shoots were strongly significant in the early June and July respectively (P<0.01). Relative stable variations in population demography and physiological traits between the two populations indicated that they are divergently in the Songnen Plain.  相似文献   
85.
There has been growing concern over the build-up of greenhouse gase(GHGs) in the atmosphere, particularly carbon dioxide (CO2), as acause of global warming. The IPCC Third Assessment Report (2001) suggests two ways in which the choice of materials could berelevant. First, some materials, particularly wood, have the advantage thatthey continue to hold carbon (C)in their cells even after being convertedto products. The implications of this feature are well researched. Second,an area that is not well researched relates to the different energyrequirements for producing similar products made with different materials. Using the findings of recent research, this paper compares the energyrequirements and C emissions of manufacturing a product using wood withthat of other materials. The case study of utility poles demonstrates thepositive C and global warming consequences of the lower energyrequirements of wood in the U.S., compared to other materials such assteel or concrete. It demonstrates that GHG emissions associated withutility poles are a small but significant percent of total US annual emissions. Wood utility poles are associated with GHG emission reductions of 163Terragrams (Tg) of CO2 when compared with steel poles. This isabout 2.8 percent of US annual GHG emissions, which are estimated atabout 5.28 Petragrams (Pg) of CO2 annually. Thus, the use ofwooden utility poles rather than steel results in a small but significantreduction in total US emissions.  相似文献   
86.
IntroductionBeforethe 1 980sconventionaltreatmentprocessesofphenolswastewateraresolventextraction ,physicaladsorption ,chemicaloxidationandaerobicbiologicalprocess.Amongthebiologicalunitprocessesactivatedsludgeprocessismainone.Afterthe 1 980sanaerobicbiologic…  相似文献   
87.
磷肥厂副产氟硅酸利用的新方法   总被引:4,自引:0,他引:4  
以磷肥厂副产氟硅酸为原料 ,加上碳酸钠 ,在适宜的工艺条件下反应 ,制取符合GB42 93— 84一级品的氟化钠和符合GB10 5 71— 89的白炭黑。该工艺具有原料易得、能耗低、成本低、投资省、无污染、经济效益好等优点  相似文献   
88.
测定了25℃时活性炭自水中吸附苯、苯酚、苯胺、对-氯苯酚、苯甲酸、对-羟基苯甲酸、对-氯苯胺、硝基苯、对-氨基苯甲酸、对-硝式苯酚、对-硝基苯胺、对硝基苯甲酸的等温线,它们的等温线均为Langmuir型的,利用Langmuir参数计算了吸吸标准自由能变化△G^0,计算结果表明,△G^0具有加和性,即化合物的△G^0是组成该化合物各基团贡献之总和,化合物的分子量及分子连接性指数与△G^0有近似的线性关系。  相似文献   
89.
载甲苯活性炭微波脱附再生试验   总被引:1,自引:0,他引:1  
研究了利用微波对载甲苯饱和活性炭的辐照再生。从甲苯的脱附和回收率2个方面探讨了活性炭再生的工艺条件。得出工艺的最佳条件:微波功率为500W、载气流速为300mL/min、辐射时间3min、活性炭量为10g。  相似文献   
90.
ACF的结构及其滤材特性的研究   总被引:3,自引:0,他引:3  
根据活性炭纤维与颗粒状活性炭的平行实验,对比了ACF与GAC的物化特性和基本结构,以说明ACF作为新型环境功能材料的特点,在实验室建立的流动法测定材料吸附特性的系统中,对ACF在不同流量下对不同上游浓度污染气体(NH3)的吸附性能进行了测定,获得了ACF的穿透曲线,对其吸附性能与吸附床流量和上游浓度进行了相关分析,并对以ACF为滤料的空气过滤器的除污性能进行了测试。  相似文献   
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