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1.
为准确、快速测定锂离子电池正极材料LiCoxMn2-xO4中锰、钴的含量,给出了一个快速、简便的测定方法。提出了用络合滴定法测定锰含量,返络合滴定法测定锰、钴总量,再利用差减法计算出钴含量。相关的进行了酸溶解选择试验、锰含量测定条件选择试验、总量测定指示剂选择试验。最后,对锂离子电池正极材料LiCo0 1Mnl 9O4中的锰、钴含量进行了测定,结果表明,具有较高的精密度和准确度。  相似文献   

2.
不同水位梯度小叶章叶绿素含量试验研究   总被引:6,自引:2,他引:6  
选择三江平原典型湿地植物———小叶章(Calam ogrostis angustifolia)为研究对象,通过人工试验控制水位条件,以对植被的非破坏性为原则,应用SPAD-502叶绿素仪测定该群落的优势种小叶章在5种不同的水位条件下的顶端第3位叶的叶绿素含量,定量地揭示了小叶章群落的优势种小叶章植株的叶绿素含量在人工控制试验条件下的季节性动态变化规律,及其与水位梯度之间的关系。6月中旬至8月中旬2个月时间的人工试验结果显示:①在设定的5种水位条件下,小叶章植株叶绿素含量随水位的升高,先下降而后上升,表明生境的水位条件明显影响小叶章种群植株的叶绿素含量;②对同一水位梯度而言,在试验期间,小叶章植株的叶绿素含量呈递减的季节性变化,反映了叶绿素含量的变化与小叶章植株生长发育的季节性变化特点具有统一性。③在试验期间,小叶章植株叶绿素含量的下降速率随着水位梯度的升高而逐渐增大。  相似文献   

3.
通过L27(9×39)混合水平正交试验确定天青石矿浮选的捕收剂和优化的工艺条件,具有试验次数少、考察因素充分的优点。正交试验的极差分析结果显示,捕收剂种类和捕收剂浓度对回收率的影响最大,原矿来源和捕收剂种类对精矿品位的影响最大。通过试验选择出对天青石矿捕收效果好的捕收剂,即十二烷基硫酸钠、十六烷基三甲基溴化铵和单烷基磷酸酯,初步得到一些关键工艺条件:浮选时间(10~15 min)、叶轮转速(2 340 r/min)、矿浆中固体质量分数(25%)和药剂与矿样的质量比(2∶1000)。  相似文献   

4.
高分散氢氧化镁的制备   总被引:11,自引:2,他引:9       下载免费PDF全文
以氯化镁和氨水为原料,进行各种工艺条件的试验,在此基础上通过加入外加剂获得过滤、洗涤性能良好的Mg(OH)2沉淀,并提高了产品的收率。根据试验得到最佳的工艺条件,制各出纯度高、成本低的氢氧化镁及氧化镁。  相似文献   

5.
纳米氢氧化镁的合成方法   总被引:8,自引:0,他引:8       下载免费PDF全文
以氯化镁和氨水为原料,进行各种工艺条件的试验,在此基础上通过加入各种分散剂获得过滤、洗涤性能良好的氢氧化镁沉淀,并加一定的CaCl2作为添加剂大大提高了产品的收率。根据试验得到最佳的工艺条件,制备出纯度高、成本低的纳米氢氧化镁。  相似文献   

6.
根据矿石的物质成份及化学成份,对矿石样品作了碱法和酸法搅拌浸出试验研究,探讨了碱、酸、氧化剂用量、浸出温度、时间等条件对铀的浸出率影响,并选用较好的工艺参数作验证试验。通过试验证明:用碱、酸法在一般搅拌条件下,均能获得较高的浸出率,属于易处理类型矿石。  相似文献   

7.
滦平郁金香引种驯化试验研究   总被引:1,自引:0,他引:1  
本文根据郁金香的生物学特性,结合我国河北滦平县的气候,土壤等自然资源条件,自1991年起,中国科学院滦平试验站从国内外引种50多个郁金香品种,经过几年的栽培,驯化试验,发现郁金香在当地的生长发育状况表现出:生根时间短,球根后期生长良好,经济效益等特点,试验研究证明燕山地区具备了郁金香种球生产的基本自然条件。  相似文献   

8.
周坚华  Y F ZHOU  周杰 《中国沙漠》2009,29(6):1186-1195
大气环流动力条件是沙尘暴发生、发展的重要影响因素之一。提出了一种新的沙尘暴分析预测模式,它以TOMS-EP卫星逐日大气气溶胶指数(Aerosol Index)数据提取区域气溶胶指数积分强度和以西风急流表征的大气环流动力条件,通过给出两者的相关性,来实现分析预测沙尘暴的目的。与此前有关沙尘暴预报的研究相比,有如下进展:①提出和试验了通过TOMS-EP数据提取大气环流动力条件的方法;②修正了区域气溶胶指数积分强度的定义和改善其提取精度;③提出和试验了表现扬沙强度的气溶胶指数积分强度与环流大气环流动力条件之间较稳定的统计相关形式,和试验分析了季节对这种相关关系的影响;④试验和分析了沙尘暴起尘的环流动力条件。本研究提出的模式/方法有可能为分析预报沙尘暴的发生时间和强度提供新的参考数据。  相似文献   

9.
地形条件约束下的区域发展模式选择   总被引:1,自引:0,他引:1  
实践已经证明,资源环境是人类社会生存和发展的基础所在。而区域发展是人类经济社会活动发展在空间上的表现形式,所以资源环境也是区域发展的基础所在,地形条件则是制约区域资源开发广度和深度的重要因素。为此,在假定区域其他投入要素不变的前提下,深入分析了地形条件和区域发展之间的机理关系,并选择具有较强代表性的京九铁路和陇海铁路作为实例,利用图形分析和相关分析方法,实证研究了沿线地形条件与经济社会发展之间的关系。通过研究发现地形条件能够通过交通运输负担影响区域发展,地形条件简单的地区,经济社会活动承担的交通运输负担较轻,经济社会发展水平较高。因此,不同地区应根据自身的资源环境基础和地形条件,选择适宜于自身发展的区域发展模式,避免发展模式的雷同,尤其山地丘陵地区应该选择物质流动负担较小的经济活动。  相似文献   

10.
黄淮海平原风沙化土地果树栽培技术研究   总被引:2,自引:1,他引:2  
李晓云  张小军 《中国沙漠》1996,16(3):319-325
为治理、开发黄淮海平原风沙化土地,3年间,从国内外引入149个果树品种,建果园15.3hm2。历时7年,选择出良种28个,有苗百万株,推广、辐射面积0.66hm2。研究表明:在现有条件下,本区采用引进选择、试验示范、推广辐射的办法,进行大穴栽植,截断淤积层,矮化密植,四季修剪,植物生长剂调控树体,少量、多次、浅施肥料,增施有机肥,间作留茬,冬春少耕、免耕,早防病虫害等一整套果树栽培、管理技术,是发展黄淮海风沙化地区果林业的一条快速、可靠、有效的方法。  相似文献   

11.
Many of the important questions facing farming systems in the world today require long-term studies to provide meaningful information and answers. A long-term agronomic experiment (LTAE) should (1) have long-term objectives; (2) study important soil processes or ecological processes; and (3) be related to the productivity and sustainability of systems. A well established LTAE can provide both insights into how the system operates and foresight into where the system goes. The prerequisites for setting up a LTAE are the secured land, continuous funding and dedicated scientists. A number of principles must be considered carefully when establishing a LTAE, (1) the site must be representative of large areas; (2) the treatments should be simple, but focusing on the big questions; (3) the plots should be large enough to allow subsequent modification of the experiment if this becomes necessary; (4) crop rotations should minimise, wherever possible, the risk of build-up of pests and diseases, and rotational phase should be considered in a rotational experiment; (5) a clearly defined experimental protocol should be developed to ensure data collected is scientifically valid and statistically analysable, but with flexibility to allow essential changes; (6) soil samples, possibly plant samples, should be achieved to provide better answer to the original questions when new, perhaps more accurate analytical techniques are developed, or answer new research questions that were not considered in the original design. The MASTER experiment in Australia was used as a case study to demonstrate how these principles are implemented in practice.  相似文献   

12.
钟伟青 《热带地理》1995,15(2):162-167
目前地貌学的研究方法可归纳为三种:①野外实地考察和记录方法;②定位观测和实地实验方法;③室内实验与模拟方法。地貌学的发展历史表明,地貌实验与模拟是地貌学今后发展的主要方向。  相似文献   

13.
李景保  邓名金 《热带地理》1994,14(2):172-179
本文讨论了地理学实验的基本特点与局限性,及其在地理学研究,教学上的应用,把地理学实验技术加以归纳总结,使之理论化,系统化和规范化,并从培养技术人才,着眼于实验手段现代化等方面提出了如何更好地应用和发展地理学实验技术的设想。  相似文献   

14.
Summary. Refraction seismic profiles in the Alpine area occasionally show seismic 'shadows' which cannot be explained by a horizontal low-velocity channel. An example is demonstrated where the low P -velocity zone (Flysch) dips below a wedge of high P -velocity (the Calcareous Alps) which is a typical Alpine structure. This feature has been studied by means of a seismic model experiment. The corner of the wedge works as a source of diffracted P -, S - and Rayleigh-waves, when met by seismic waves. The diffracted waves can be distinguished from conventional waves by their amplitude–distance relation when the extinction coefficient is well known by an independent experiment.  相似文献   

15.
土壤可蚀性研究述评   总被引:19,自引:0,他引:19  
宋阳  刘连友  严平  曹彤 《干旱区地理》2006,29(1):124-131
土壤可蚀性是土壤对侵蚀作用的敏感性。对土壤可蚀性的研究是认识土壤侵蚀机理的一个重要环节。土壤可蚀性可以通过测定土壤的理化性质、水冲、模拟降雨、小区和风洞试验测定,可以使用土壤侵蚀模型与诺谟图计算土壤可蚀性。研究中产生了许多可蚀性指数和计算公式。土壤可蚀性是一个相对的概念,它受空间变化、土壤性质的时间动态变化和人类活动等因素的影响。在土壤可蚀性的研究中存在着一些不足,具体表现为:农田土壤是土壤可蚀性研究的主要对象,区域之间的土壤可蚀性缺乏对比,因此加强对土壤可蚀性机理、实验与风水复合侵蚀作用下土壤可蚀性的研究有着十分重要的意义。  相似文献   

16.
Soil erodibility is an important index to evaluate the soil sensitivity to erosion. The research on soil erodibility is a crucial tache in understanding the mechanism of soil erosion. Soil erodibility can be evaluated by measuring soil physiochemical properties, scouring experiment, simulated rainfall experiment, plot experiment and wind tunnel experiment. We can use soil erosion model and nomogram to calculate soil erodibility. Many soil erodibility indices and formulae have been put forward. Soil erodibility is a complex concept, it is influenced by many factors, such as soil properties and human activities. Several obstacles restrict the research of soil erodibility. Firstly, the research on soil erodibility is mainly focused on farmland; Secondly, soil erodibility in different areas cannot be compared sufficiently; and thirdly, the research on soil erodibility in water-wind erosion is very scarce. In the prospective research, we should improve method to measure and calculate soil erodibility, strengthen the research on the mechanism of soil erodibility, and conduct research on soil erodibility by both water and wind agents.  相似文献   

17.
水蚀风蚀过程中土壤可蚀性研究述评   总被引:4,自引:1,他引:3  
1 IntroductionSoil erosion is the process of detachm ent and transport of soil particles caused by w ater andw ind (M organ,1995).Soilerosion by w ater and w ind leads to decline in soilfertility,brings ona series of negative im pacts of land degradation …  相似文献   

18.
Lakes regulate the water and heat exchange between the ground and the atmosphere on different temporal and spatial scales. However, studies of the lake effect in the high-altitude Tibetan Plateau(TP) rarely have been performed until recently, and little attention has been paid to modelling of frozen lakes. In this study, the Weather Research and Forecasting Model(WRF v. 3.6.1) is employed to conduct three numerical experiments in the Ngoring Lake Basin(the original experiment, an experiment with a tuned model, and a no-lake experiment) to investigate the influences of parameter optimization on the lake simulation and of the high-altitude lake on the regional climate. After the lake depth, the roughness lengths, and initial surface temperature are corrected in the model, the simulation of the air temperature is distinctly improved. In the experiment using a tuned model, the simulated sensible-heat flux(H) is clearly improved, especially during periods of ice melting(from late spring to early summer) and freezing(late fall). The improvement of latent-heat flux(LE) is mainly manifested by the sharp increase in the correlation coefficient between simulation and observation, whereas the improvement in the average value is small. The optimization of initial surface temperature shows the most prominent effect in the first year and distinctly weakens after a freezing period. After the lakes become grassland in the model, the daytime temperature clearly increases during the freezing and melting periods; but the nocturnal cooling appears in other stages, especially from September to October. The annual mean H increases by 6.4 times in the regions of the Ngoring Lake and the Gyaring Lake, and the LE declines by 56.2%. The sum of H and LE increases from 71.2 W/m2(with lake) to 84.6 W/m2(no lake). For the entire simulation region, the sum of H and LE also increases slightly. After the lakes are removed, the air temperature increases significantly from June to September over the area corresponding to the two lakes, and an abnormal convergence field appears; at the same time, the precipitation clearly increases over the two lakes and surrounding areas.  相似文献   

19.
Atriplex halimus L. is a valuable fodder shrub that has been widely used in arid Mediterranean regions. However, its response to several cumulative years of grazing management remains uncertain. Accordingly, we conducted a three-year experiment in south-eastern Spain to analyze the influence of repeated seasonal (winter-spring) sheep browsing on young A. halimus plants. Shrub growth, fodder and wood production, plant compactness and shoot moisture content were assessed through regular monitoring of the size of shrubs, sampling of summer shoots, and destructive procedures at the end of the experiment. Shrubs were on two closely located sites but where soil quality and water availability were different. At the better location, browsed shrubs grew less and were significantly smaller (P < 0.001) than the non-browsed saltbushes. In contrast, differences between groups were minimal where the growth conditions were poorer. In all cases, shrubs resprouted vigorously and maintained fodder production throughout the experiment. Browsing affected shrub structure, resulting in smaller but more compact plants (2.20 vs. 1.24 g dm−3, P < 0.001), but their proportion of fodder remained similar. The spring grazing increased shrub-shoot moisture content in the summer (62.5% vs. 56.0%, P < 0.001). Overall, this species responded very positively to repeated seasonal grazing.  相似文献   

20.
赵进平  李涛  李淑江  李翔 《极地研究》2008,20(3):287-298
本文介绍了在北冰洋冬季进行人造光源海冰光学实验中光源所产生的辐射场结构及其特性。文章论证了光源最小允许尺度需要由仪器的视场参数和距光源的最大距离同步确定。对光源测试的结果表明,荧光灯光源存在光源不稳定性、光场空间结构不均匀性、光场空间发散性、光源温度变化效应等可能影响测量结果的问题。文章仔细分析了上述问题可能引起的误差,在实验方案设计中采取三方面措施保证测量质量:光源的尺寸满足仪器的视场、现场定标、在有效测量区内测量。其中,现场定标是核心环节,是克服光场结构问题的关键。实践表明,光源形成的光场与实验方案必须非常协调才能取得理想的实验结果。本文利用获得的光场特性指导现场实验方案的制定,将光场结构产生的测量误差降低到最小。这次在北极开展的海冰人造光源实验没有先例,取得的经验对今后的研究有重要参考价值。  相似文献   

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