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961.
山西煤系沉积型“阳泉式”硫铁矿床是山西的主要矿床类型。其分布广、储量大 ,且伴生、共生有多种稀有、稀土元素。通过综合回收利用 ,可以减少环境污染、提高资源利用率、扩大资源使用范围、延长矿山服务年限、增强矿山企业的经济效益和社会效益 ,使山西化工矿业持续、稳定、健康发展 相似文献
962.
963.
Dimethylsulphide (DMS) has been implicated in climate change as a possible negative feedback to global warming, and several Models have been developed that simulate the production of DMS in the marine environment. The focus of this study is to improve the nitrogen based Gabric Model, using field data collected during the Southern Hemisphere First Marine Aerosol Characterisation Experiment (ACE-1) in the Southern Ocean in 1995. Two Model Runs (Series A and B) were carried out with six simulations of varying biotic and abiotic inputs applied over the voyage transect (41-48°S), reflecting Model default values or field values from the experiment. The abiotic inputs were time-step, dissolved dimethylsulphoniopropionate (DMSP) and DMS, and the biotic nitrogen inputs were from phytoplankton, bacteria, zooflagellates, large protozoa, micro and mesozooplankton. The focus of the abiotic assessment was nutrient (nitrate) uptake and dissolved DMSP and DMS output. Model output of the biotic compartments was assessed for congruence with predicted ecological patterns of succession.
Despite a limited data set the study provides a good insight into the utility of the Model, which functioned as a heuristic rather than predictive tool. In simulation 1 (Series A) where the only field value was nitrate, all latitudes from 41-48°S concurred with the ecological succession predicted by the Model authors and the successional pattern predicted by other researchers, with a double phytoplankton peak indicating remineralisation of nitrogen via the microbial loop. In many simulations the Model produced lower values of dissolved DMS than were measured, and production of DMS in the Model appears constrained. However, in simulation 5 (Series A) DMS model outputs were closest to the mean dissolved DMS levels reported on RV Discoverer. In this simulation, field values were used for phytoplankton, nitrate, dissolved DMSP and DMS, with bacterial abundance and micro and mesozooplankton increased over their Gabric default values. Also, the phytoplankton double peak occurred earlier, as did the peaks in bacteria, zooflagellates, and large protozoa. Simulations that deviated more significantly from the predicted successional patterns were characterised by single peaks in phytoplankton growth and delayed bacterial growth. Series C simulations at latitude 43°S, in an attempt to reduce phytoplankton predation by bacteria, increased DMS output reasonably successfully. However, significant recalibration of the Model is recommended in conjunction with field studies to gather vital background biological data - particularly in the areas of nutrient limitation, phytoplankton speciation, and the cellular content of the DMS precursor compound, DMSP. 相似文献
Despite a limited data set the study provides a good insight into the utility of the Model, which functioned as a heuristic rather than predictive tool. In simulation 1 (Series A) where the only field value was nitrate, all latitudes from 41-48°S concurred with the ecological succession predicted by the Model authors and the successional pattern predicted by other researchers, with a double phytoplankton peak indicating remineralisation of nitrogen via the microbial loop. In many simulations the Model produced lower values of dissolved DMS than were measured, and production of DMS in the Model appears constrained. However, in simulation 5 (Series A) DMS model outputs were closest to the mean dissolved DMS levels reported on RV Discoverer. In this simulation, field values were used for phytoplankton, nitrate, dissolved DMSP and DMS, with bacterial abundance and micro and mesozooplankton increased over their Gabric default values. Also, the phytoplankton double peak occurred earlier, as did the peaks in bacteria, zooflagellates, and large protozoa. Simulations that deviated more significantly from the predicted successional patterns were characterised by single peaks in phytoplankton growth and delayed bacterial growth. Series C simulations at latitude 43°S, in an attempt to reduce phytoplankton predation by bacteria, increased DMS output reasonably successfully. However, significant recalibration of the Model is recommended in conjunction with field studies to gather vital background biological data - particularly in the areas of nutrient limitation, phytoplankton speciation, and the cellular content of the DMS precursor compound, DMSP. 相似文献
964.
变革一切不合理的生产组织和管理的方式,厉行节约,反对浪费,清除和防治各个环节造成浪费的痼疾,最大优化资源利用;以人为出发点和落脚点,建立富有特色的企业文化,实现民主管理、科学管理、自我管理,调动一切可以调动的因素,开拓创新,科学发展,创造绿色业绩。具有中国特色的精准之道,精益求精,乃希望之路,成功之路。 相似文献
965.
决策支持系统模型库管理系统的研究 总被引:2,自引:0,他引:2
作者在文中通过对稠油开采决策支持系统模型库管理系统的研究,提出并实现了一种决策支持系统模型管理系统建立的模型。并应用到稠油开发采决策支持系统中,取得了较好的应用结果。 相似文献
966.
967.
玉石洼铁矿伴生钴的赋存状态及综合利用初探 总被引:1,自引:0,他引:1
玉石洼铁矿伴生的钴含量较高,主要以类质同象形式存在于伴生的黄铁矿中,与硫存在着正相关关系,应用合适的提钴工艺,黄铁矿中大部分的钴可以提取出来。此区钴资源量丰富,如能综合利用,潜在经济效益可观。 相似文献
968.
Geothermal Characteristics and Geological Implications of Major Tectonic Units in China 总被引:4,自引:0,他引:4
969.
1971—2000年中国陆地植被净初级生产力的模拟 总被引:4,自引:0,他引:4
利用植被与大气相互作用模式(AVIM),基于气象台站的观测资料模拟了1971—2000年中国陆地生态系统NPP的变化特征.结果表明:1971—2000年我国陆地植被年均NPP变化范围在0~987.67 gC·m-2·a-1,全国平均值为349.74 gC·m-2·a-1,30 a呈现出递增的变化趋势.对各类植被NPP的模拟显示,最近30 a我国热带雨林、落叶阔叶林以及有地被层的阔叶林的年均NPP减小,而混交林、常绿针叶林、落叶针叶林、有裸土的灌丛、草地以及作物的年均NPP均为增加趋势.由于采用了先进的农业技术,与自然条件下我国作物的年均NPP变化相比,我国实际的粮食单产在上述时期呈显著的增长,表明了人类活动对于我国陆地植被净初级生产力有着深刻的影响. 相似文献
970.
以奈曼旗为例,根据农牧业生产综合模型对农牧业生产的主要方面进行了分析。农牧业生产中,资本对产出的贡献最大,有效劳动和土地生产力次之,表明奈曼旗的生产处于规模报酬递增的增长时期。农牧业生产基本呈指数增长,且1951-1980年增长较缓,1980年以后增长很快。固定资本的增长较为稳定和缓慢,生产费用的增长具有波动性。生产费用与施肥量和沙漠化程度关系显著,当年生产费用与上年产出高度相关,同时由于生产费用对产出增加有很高的贡献,说明农牧交错区的农牧业发展中存在负反馈关系。土地生产潜力利用率反映了农牧业生产与土地生产力之间的关系,该利用率在0~0\^4之间波动,并且1980年以前利用率低且波动小,说明这段时期的农牧业生产整体水平不高,1980年以后利用率高且波动大,资本对产出贡献的比重下降,土地生产潜力的重要性相对增大。 相似文献