钛精矿中亚铁的测定     

张念慈 《安徽地质》1998,(4)

研究用重铬酸钾容量法测定钛精矿中的亚铁,对试样的分解、滴定条件及防空气氧化措施等做了较详细的试验。所制定的分析方法准确可靠,操作简便,已于１９９７年通过冶金部初审。  相似文献   

环渤海三省一市溶解态无机氮容量总量控制   总被引：4，自引：0，他引：4  

王修林  CUI Zheng-Guo  李克强  HAN Xiu-Rong  李雁宾  ZHU Chen-Jian 《中国海洋大学学报(自然科学版)》2008,38(4)

对溶解无机氮(DIN)容量总量控制实施的具体原理和方法进行了研究.1979～2005年渤海DIN排海通量总体上呈"N"形变化趋势,年均入海通量34×104 t/a.基于多介质海洋环境中的迁移-转化箱式模型,推算出在Ⅰ类、Ⅱ类、Ⅲ类和Ⅳ类海水水质标准下渤海DIN极小海洋环境容量分别为(22,29,38,47)×104 t/a.分配容量优化结果表明,在在国家Ⅰ类、Ⅱ类海水水质标准条件下,2010年辽宁、河北、天津和山东三省一市DIN排放量均超过其最大允许排放量,均需不同程度的削减,平均削减预计排放量的37%和29%.  相似文献   

基于非线性动力学模型的旅游生态容量分析   总被引：1，自引：0，他引：1  

吕龙  黄震方  吴江 《地球信息科学学报》2009,11(2):163-168

近年来,大量增加的游客给景区的旅游生态容量带来了较大的压力,矛盾日渐突出。为了实现景区的环境保护与可持续发展,研究游客活动量与景区旅游生态容量之间的关系是十分必要的。本文从非线性动力学观点出发,构建二者非线性动力学模型,并进行平衡态分析。研究结果表明:(1)系统要达到可持续发展,必须建立在景区环境的自我更新能力及人工恢复程度之和大于外界污染水平,且游客的增长率必须保持在较低水平的基础上;(2)景区旅游生态容量的承载力是有限的,所能容纳的游客也是有限的,超过一定的限度就会引起生态系统失衡。采取严格控制游客量,加强对景区内外环境的保护和改善、提升游客素养等措施,对于系统的协调发展至关重要。  相似文献   

Fuzzy comprehensive evaluation model for water resources carrying capacity in Tarim River Basin, Xinjiang, China   总被引：12，自引：0，他引：12  

Lihong Meng  Yaning Chen  Weihong Li  Ruifeng Zhao 《中国地理科学(英文版)》2009,19(1):89-95

This paper explores the method of comprehensive evaluation of water resources carrying capacity and sets up an evaluation model applying the fuzzy comprehensive evaluation method. Based on the data of nature, society, economics and water resources of the Tarim River Basin in 2002, we evaluated the water resources carrying capacity of the basin by means of the model. The results show that the comprehensive grades are 0.438 and 0.454 for Aksu and Kashi prefectures respectively, where the current water resources exploitation and utilization has reached a relative high degree and there is only a very limited water carrying capacity, 0.620 for Kizilsu Kirgiz Autonomous Prefecture, where water resources carrying capacity is much higher, and in between for Hotan Prefecture and Bayingolin Mongolian Autonomous Prefecture. As a whole, the comprehensive grade of the Tarim River Basin is 0.508 and the current water resources exploitation and utilization has reached a relative high degree. Thus, we suggest that the integrated management of the water resources in the basin should be strengthened in order to utilize water resources scientifically and sustainably.  相似文献   

浅析气象服务对民航运输业全过程决策的支持作用     

吴风波  肖海平  成永勤 《广东气象》2015,37(1):47-51

从机场拟选阶段、航空公司航班计划制定、空域容量以及协同决策等多方面分析航空气象对我国民航运输业全过程决策的支持作用。分析表明,综合分析收集到的场址气象、气候资料,有助于择优确定跑道长度、跑道方向,掌握雷暴、台风、低云、低能见度、大风、冰雹等恶劣天气的季节特征、日变化等特点,有利于有效地确定机场选址、减少天气对飞行的影响、提高飞行安全;在航空运输业航班计划的制定过程中,充分考虑恶劣天气的年际、季节性规律和日变化情况、出现频率、持续时间等特征,既能保障民航飞行安全,又能充分利用有利的天气条件最大限度地编排航班、提高航空公司和机场的运营效益;广州机场、终端区关键点和关键区域的0—1 h短时临近外推强对流天气预报产品具有较高准确率,可为管制部门制定空域流量决策,提高强对流天气情况下有限空域的使用率,保障航空运行安全,提高了航空公司航班进出港率、空域使用率;数值模拟实验能较好地再现2013年春季2次典型强飑线过程,为建立1—6 h强对流天气短时预报,实现短时临近外推和数值模拟融合预报提供了可行性参考。  相似文献   

多功能旋挖钻机长螺旋钻具的研制          下载免费PDF全文

王三牛  李洪  宋刚  邵玉涛 《探矿工程》2010,37(5):45-48

通过对长螺旋钻进过程中阻力矩的计算,得出了不同直径和孔深情况下的阻力矩值,依此对长螺旋钻具的强度进行比对,给出了不同口径的长螺旋钻具参数。还介绍了长螺旋钻头的不同结构形式及配套器具,简述了多功能钻机长螺旋钻进施工工艺。  相似文献   

浅析野外金的快速分析方法     

高翠芬 《山东地质》2010,(10):44-47

该文选择野外快速测金的2种方法：氢醌容量法和目视比色法,从原理、试样分析、富集方法、吸附机理、解脱方式、试剂及分析手续几方面进行对比分析,着重对氢醌容量法作研究和完善工作。针对通过比对实验,确立分析测试条件,选择确定了快速、简便、经济的测试流程,并应用于样品测试,提高了检测速度。  相似文献   

Soil and vegetation seasonal changes in the grazing Andean Mountain grasslands     

MU?OZ María ángeles  FAZ ángel 《山地科学学报》2014,11(5):1123-1137

Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna（Vicugna vicugna） and alpaca（Lama pacos）. The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined： total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.  相似文献   

遥感图像信息容量与植被指数的耦合关系研究     

李良军  王旭红  妙丹  申怡 《干旱区地理》2014,(2)

遥感信息容量能表征地表复杂度,为深入探究信息容量与植被之间关系,研究对植被盖度、NDVI、RVI等5种植被指数的均值、均方差与信息容量做了多种回归分析。结果表明:植被覆盖度均值、植被指数均方差与信息容量有明显相关性,其中植被盖度均方差与信息容量相关性最大,确定系数R~2为0.851 8;相关系数最大R~2为0.8642,说明遥感信息容量与植被指数、植被盖度之间有明显的相关性,证明了信息容量能有效地表征地表覆盖的变化。  相似文献   

工程勘察设计行业未来发展趋势     

无 《中国勘察设计》2014,(5):36-39

固定资产投资减少,市场空间容量增幅下滑,行业竞争激烈,投资结构发生变化,业务结构将会发生改变2013年年底召开的中央经济工作会议明确提出,要继续把握好＂稳中求进＂的工作总基调,引导当前中国经济稳步经历＂两个转变＂,即从高速增长转为平稳增长,从规模扩张式转为治理效益型发展。从高速增长转为平稳增长,意味着过去依靠高速增长的投资拉动带来的＂遍地开花式＂高速增长将一去不复返。  相似文献