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921.
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924.
本文用平均风速和最大风速法对若尔盖等三地的韦伯分布参数k、c进行估算,并用韦伯分布计算风能的指标。计算表明:若尔盖、红原属风能可利用区,用风力发电是有利用价值的;阿坝属风能贫乏地区。 相似文献
925.
顾客满意状态与企业利润率之间有着密切的联系,提高顾客满意度成了许多企业的重要经营目标.对红旗连锁的现状进行了分析,确定顾客满意度的各项指标与权重,建立了一个完善的指标和级度体系,通过对红旗连锁的顾客展开调查,综合评价了顾客现有的满意程度,并提出了提高顾客满意度的途径. 相似文献
926.
11月22日,由中国海洋学会、中国太平洋学会和河北省海洋局共同主办的第六届海洋强国战略论坛在石家庄市隆重召开。本届论坛以"保护渤海环境,推动海洋生态@明建设"为主题,提出举科学之力、聚专家之智,共同探讨海洋强国的战略内涵,探索决策海洋强国的理论,寻求建设海洋强 相似文献
927.
Sediment-water fluxes of N and P species in the Bohai Sea were investigated in September-October 1998 and April-May 1999. The benthic fluxes of nutrient species were determined by incubating sediment core samples with bottom seawater bubbled with air or nitrogen. NO^-2,NH4, dissolved organic nitrogen (DON) and phosphorus (DOP), total dissolved nitrogen (TDN) and phosphorus (TDP), and PO4^3- showed a net exchange flux from seawater to sediment, while NO^-3, dissolved inorganic nitrogen (DIN) and SiO3^2- were released from sediment to seawater in the Bohai Sea. Sediment-water nutrient exchange increases DIN and reduces the phosphorus load in the Bohai Sea. The release of silicate from sediment to overlying seawater reduces potential silicate limitation of primary production resulted from decrease of riverine discharge.The exchange flux of nutrients showed no obvious seasonal variation. The present study showed that the concentrations and composition of nutrients in the water column were affected by suspended sediment, and that not all the exchangeable phosphate in sediment could be released via sediment resuspension. 相似文献
928.
LeQuocDoanh HaDinhTuan 《山地科学学报》2004,1(3):270-275
More than 30 ethnic groups are now living in northern mountainous regions, Vietnam, mainly relying on shifting cultivation with the fallow period being shortened from time to time. Naturally, soil fertility reduces from cycle to cycle, entailing the reduction of productivity. Large areas of moderately sloping lands suitable for upland agriculture have become bare after many cultivation-fallow cycles. The soils there have been severely degraded with more toxicity, low porosity, low water retention capacity and poor floral diversity. Normally, these lands cannot be used for food crop cultivation. So farmers in uplands have to rely on slash-and-burn practices for their livelihood. As there is no more forest with good soil in medium slopes, farmers go to cut forests in watershed, high slope lands and old forests up to the mountains‘ top. There are ecologically and environmentally very sensitive areas, so their destruction will inevitably cause hazardous consequences in the whole basin. Meanwhile,cultivation in these areas has low economic efficiency and sustainability because the crop yield may decrease very fast due to severe erosion as the higher the slope, the more serious erosion. Consequently living standards of highland farmers remain low and unstable. Sustainable farming on these lands in the perspective of a seriously deteriorated ecology and environmental is not an easy task. There have been many projects trying to help mountainous farmers get out of their vicious circle. However, due to different reasons, the results gained are low, and in some cases,things ceased to move after the projects phased out. During past few years, based on the farmer experiences, the Vietnam Agricultural Science Institute has cooperated with local and international partners to implement different projects in order to solve the problems by developing simple, easy and cheap cultivation technologies, which can be accepted and applied by local poor farmers for sustainable agricultural production. The first results of our activities offered good opportunities for sustain food production, improve soil health, recharge of aquifers,and enhanced household income for better rural lively hoods in the upland eco-regions of northern Vietnam. 相似文献
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930.
3月7日至8日,全省土地利用规划管理工作座谈会在乐清雁荡召开。来自全省各地(市)国土资源局长、省厅规划处有关人员参加了会议。会上,省国土资源厅马奇副厅长部署了2007年全省土地利用规划管理工作。她指出,今年的工作重点主要抓好规划管理和计划管理两方面工作:一要加强规划管理工作,二要加强计划管理工作。马奇副厅长客观分析了2007年我省用地指标计划管理供应总量情况。对于折抵指标使用,2007年将继续作为指令性指标纳入控制计划;对于建设用地复垦置换和周转指标,必须要用足用好相关政策;对于转而未供的55万亩土地,今年要再完成供地20万亩。马奇副厅长还就2007年计划管理办法变化情况进行了分析。一是将未利用地列入计划管理范围;二是实行切块指标分解的办法,总量70%按经济指标(GDP、财政收入、人均耕地等)计算下达分解各市,30%依据各地工作开展情况(用地情况、标准农田建设完成情况、省委托造地完成情况、地质灾害避险实施情况、下山脱贫情况等)予以分解下达。对新增用地计划指标的使用,省厅将加强督查力度。会上,各市国土资源局长还就土地利用计划管理工作经验进行了交流座谈,提出了许多建设性意见和建议。[第一段] 相似文献