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1.
新疆北部20年棉花物候计算和分析--以炮台镇为例   总被引:1,自引:2,他引:1  
基于single sine物候模型计算新疆北部20年棉花日度累积值,利用系统聚类法分析20年棉花物候变化规律,建立了物候日度和棉花产量之间的回归模型。结果表明:新疆北部棉花主要物候事件播种、出苗、现蕾、开花、裂铃、吐絮和停止生长所需要的日度累积值分别为53.1853.18、109.99、360.97、635.64、1169.61和1180.02日度;聚类分析将20年划分为4个类型即冷年类型、温暖类型、热年和特热年;棉花产量(y)和全年日度累积值(x1)、棉花停止生长日度累积值(x2)和9月份以后的日度累积值(x3)之间存在正相关。  相似文献   

2.
准噶尔南部沙尘暴发生的地表条件研究   总被引:12,自引:5,他引:7  
准噶尔南部可分出沙尘暴源区、易发区和少发区(或罕见区)三类,它们包括植被状况、土壤理化性质在内的地表条件存在差异。以植被盖度、植物群落多样性和土壤表层水分为变量,在费歇(Fisher)准则下建立起源区和少发区地表特征的判别函数R=-0.0576x1-0.1345x2-0.0695x2,并确定了两者划分的阈值R0=-10.07。在此基础上,对易发区地表条件的类型归属进行判别。最终查明影响沙尘暴发生的地表条件主要是植被状况,其中最为重要的是植物群落的多样性。  相似文献   

3.
新疆玛纳斯河蘑菇湖沉积物中粘土矿物及其环境意义   总被引:3,自引:0,他引:3  
大量研究表明粘土矿物可以作为研究环境演变的载体。玛纳斯河蘑菇湖剖面位于新疆石河子市附近的一个砖厂内,本文利用x衍射法分析了该剖面的粘土矿物的类型与含量变化。这些粘土矿物主要由伊利石、蒙皂石、高岭石和绿泥石组成。对粘土矿物含量的变化分析和对比表明,玛纳斯河流域全新世气候演变可划分为4个阶段。即6.2~9.1 ka BP与1.8—3.6 ka BP为温暖湿润期,0~1.8 ka BP与3.6~6.2 ka BP为干冷期。  相似文献   

4.
LiMxMn2—xO4(M=Cr、Al)尖晶石相阴极材料研究   总被引:2,自引:0,他引:2       下载免费PDF全文
用溶胶-凝胶法制备了LiMxMn2-xO4(M=Cr、Al;x≤0.2)尖晶石相锂离子电池阴极材料。SEM表面观测显示材料的晶形好,粒度均匀,粒径小于0.5微米。电化学测试表明,低水平量(0.02≤x≤0.05)的Cr、Al掺杂材料初始容量稍有降低,但却较大地改善了循环性能。在LiMxMn2-xO4中,掺A1降低了Li^ 、Mn^3 占位的无序度;Cr^3 和Al^3 取代了其中的部分Mn^3 ,占据八面体位(16d),抑制了Jahn-Teller效应,增强了尖晶石骨架的稳定性,提高了其电化学性能。在3.0-4.3V的充放电过程中,材料中的Cr、Al都保持+3价不变,不发生氧化还原。  相似文献   

5.
谢贤宁  周园 《盐湖研究》1998,6(4):20-27
采用惰性气体保护下的高温熔融反应及氮淬冷技术,制备了xLI2S·(1—X)B2O23玻璃。利用DSC量热法研究了玻璃的非等温晶化动力学,计算得到晶化活化能E,Avrami指数n及晶化热—△H等动力学参数。实验发现,xLi2S·(1—X)B2O3硫氧化物能在X≤0.45的区域形成玻璃,x=0.25玻璃组份具有最强的抗晶化能力,而x=0.45玻璃组份最易晶化。玻璃的晶化为一热激活过程,且主要由表面成核机理控制。玻璃晶化活化能在180—100μm颗粒范围有最大值,晶化热—△H与峰值温度Tp满足线性关系。  相似文献   

6.
投稿日期:201x—x-x-xx 基金项目:XXXX科学基金资助项目(项目编号:XXXX) 作者简介:姓名(出生年-),性别(民族),籍贯,职称,学位,从事x×××方面的研究,(电话)××××,(E-mail)××x×. 通讯作者:姓名(出生年-),性别(民族),籍贯,职称,学位,从事XXXX方面的研究,(电话)XXXX,(E-mail)xxxx.  相似文献   

7.
库仑法和电化学阻抗法测量LiFePO4锂离子扩散系数   总被引:1,自引:0,他引:1       下载免费PDF全文
库仑法和电化学阻抗法是测量锂离子扩散系数有效的测量手段。以实验室自制的LiFePO4为实验电池正极材料,介绍如何用库仑法和阻抗法测试并计算电极材料的锂离子扩散系数。库仑法计算得到锂离子扩散系数由Li1-xFePO4(x=0)的9.6×10-9cm2.s-1变化为Li1-xFePO4(x=0.7)的1.1×10-11cm2.s-1。用阻抗法的两种模型,分别计算了Li1-xFePO4(x=0.65)的电池材料的锂离子扩散系数,结果分别是8.5×10-11cm2.s-1和3.1×10-12cm2.s-1。三种方法的计算结果接近。  相似文献   

8.
珠江三角洲城镇建筑覆盖近期变化研究   总被引:17,自引:5,他引:12  
基于遥感与地理信息系统技术,从1988年与1998年两个时期研究区域的TM卫星影像提取各城镇的实际建筑覆盖区面积等专题信息,并利用Arc/Info802建立珠江三角洲乡镇级空间数据库。在此基础上重点对珠江三角洲城镇建筑覆盖近期变化的空间扩展特性,并就企业、交通设施、人口、区域经济与行政体制等驱动因子进行了初步综合分析。研究表明20世纪末珠江三角洲城镇建筑覆盖总体圈层格局相对稳定,核心增长与交通指向扩展非常显著,城镇建筑覆盖区增长总量与增长速率空间分布不一致,城镇扩展强度指数空间分布也显示出核心增长与交通轴向增长显著的特征  相似文献   

9.
为了研究造纸废水中化学需氧量含量对芦苇(Phragmites australis)秆纤维形态的影响,于2015年4月28日~10月28日,以辽宁省双台河口湿地灌溉造纸废水的芦苇秆为实验材料,在芦苇的不同生长期,灌溉化学需氧量质量浓度为300 mg/L、175 mg/L和50 mg/L的造纸废水,芦苇成熟后,测定芦苇秆纤维的长度、宽度和长宽比。研究结果表明,成熟芦苇秆的纤维长度、宽度和长宽比随着水中化学需氧量含量的增加而增大。在芦苇的快速生长期灌溉化学需氧量质量浓度300 mg/L的废水,成熟芦苇秆的纤维长度、宽度和长宽比都达到最大值,分别为1.49 mm、10.35μm和143.96。造纸废水中的化学需氧量质量浓度(x)与成熟芦苇秆纤维长度(y_1)(r=0.414)、宽度(y_2)(r=0.340)和长宽比(y_3)(r=0.715)都线性正相关,其关系式分别为y_1=0.001x+0.845,y_2=0.006x+7.057和y_3=0.039x+118.508。  相似文献   

10.
在山西霍山七里峪林场,采用间接的光学测量方法对沿着海拔分布的植物群落主要层叶面积指数(LAI)进行了测量,从不同的角度对LAI的垂直分布规律进行分析。结果表明:1.海拔不同,LAI表现出很大的差异,海拔1750m左右的LAI值大于较高与较低海拔的;对LAI和海拔之间的关系进行回归,得到LAI分布的拟合方程:y=b0+b1x+b2x^2+b3x^3(R=0.712,P〈0.01)。2.同一海拔样带,阴坡LAI均大于阳坡,但对同种种群来说,阴坡树种平均胸径并不一定均大于阳坡。3.植被类型LAI比较表现为:低山针叶林〈低山灌丛〈落叶阔叶林〈落叶针叶林〈常绿针叶林;而主要群系LAI比较表现为:油松林(0.38)〈落叶松林(0.78)〈山杨林及其混交林(1.09)〈白桦林(2.00)〈辽东栎林及其混交林(3.73)。4.典型群落LAI值变化分析和人工林与天然林以,比较表明,LAI值在一定海拔达到最大值,这对于山西霍山人工林栽培和丰产林培育等具有重要意义。  相似文献   

11.
东亚夏季风的年际变化及其与环流和降水的关系   总被引:2,自引:0,他引:2  
利用1951-2006 年6-8 月NCEP/NCAR 的500 hPa 高度场、850 hPa 高度场和风场、降 水率和海平面气压以及全国600 多站的降水量资料, 选择东亚-西太平洋地区(10o-80oN, 70o-180oE) 经9 点高通滤波、EOF 分析、合成分析和其它统计诊断手段, 研究了东亚夏季风的年际变化及其与环流和降水的关系, 得到如下的结论: 1. 东亚-西太平洋地区海平面气压 存在着蒙古低压和西太平洋高压之间纬向的偶极子振荡型(APD), APD 指数可以作为东亚夏季风强度指数; 2. 东亚-西太平洋地区500 hPa 高度距平EOF 的第一模态具有明显经向东亚遥相关型特征(EAP)。EAP 指数也可以作为东亚夏季风强度指数。3. APD 指数与500 hPa (或 850 hPa) 的东亚遥相关型关系密切。APD 指数和EAP 指数存在明显的反相关关系, 它们之间的相关系数为-0.23, 已超过了10%显著检验; 4. APD 指数和EAP 指数都和我国汛期降水、东亚-西太平洋降水率关系密切, 超过5%显著性的相关区主要在长江流域以南地区至日本南部海面一带, 前者为正相关, 后者为负相关。  相似文献   

12.
Using NCEP/NCAR reanalysis geopotential height (GHT) and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure (SLP) and precipitation observations from more than 600 stations nationwide in June–August from 1951 to 2006, and focusing on the East Asia–West Pacific region (10o–80oN, 70o–180oE), interannual variation of East Asian summer monsoon (EASM) and its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such as 9-point high pass filtering, empirical orthogonal function (EOF) analysis, composite analysis and other statistical diagnosis, etc. It is concluded as follows: (1) EOF analysis of SLP in the East Asia–West Pacific region shows the existence of the zonal dipole oscillation mode (APD) between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity index of EASM. (2) EOF analysis of GHT anomalies at 500 hPa in the East Asia–West Pacific region shows that the first EOF mode is characterized with an obvious meridional East Asian pattern (EAP), and EAP index can also be used as an EASM intensity index. (3) The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa (or 850 hPa). The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient of –0.23, which passes the confidence test at 0.10 level. (4) Both APD and EAP indexes are closely correlated with precipitation during flood-prone season in China and precipitation rate over the East Asia–West Pacific region. The significant correlation area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern Japan, and the former is a positive correlation and the latter is a negative one.  相似文献   

13.
采用分子动力学(MD)模拟研究了5.55 mol·kg~(-1)氯化钙溶液的微观结构特征,尤其是溶液中高配位Ca-Cl离子团簇的结构与性质,探究了温度对于高配位Ca-Cl离子团簇的影响。结果显示,5.55 mol·kg~(-1)氯化钙溶液中,除形成[CaCl]~+、[CaCl_2]~0离子对外,还存在一些高配位[CaCl_x]~(2-)~x(x=3~6)离子团簇。高配位[CaCl_x]~(2-)~x(x=3~6)离子团簇在5.55 mol·kg~(-1)氯化钙溶液中介稳存在,易解离或进一步缔合形成更大Ca-Cl离子团簇,这可能与溶液中大量未完全水合Ca~(2+)对高配位[CaCl_x]~(2-)~x(x=3~6)离子团簇水壳层的扰动破坏有关。温度升高,氯化钙溶液中Ca-Cl离子缔合增强,但高配位Ca-Cl离子团簇的平均存在时间(t_(av))减小,这表示高温下溶液中Ca-Cl离子团簇频繁地解离与缔合,离子团聚趋势更为显著。本工作观测到的高配位[CaCl_x]~(2-)~x(x=3~6)离子团簇可能是浓氯化钙溶液Ca-Cl离子缔合过程中一种热力学不稳定结构,但这些高配位Ca-Cl离子团簇的形成可能对溶液结晶及相关化学过程产生不利影响。  相似文献   

14.
Using NCEP/NCAR reanalysis geopotential height (GHT) and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure (SLP) and precipitation observations from more than 600 stations nationwide in June–August from 1951 to 2006, and focusing on the East Asia-West Pacific region (10°–80°N, 70°–180°E), interannual variation of East Asian summer monsoon (EASM) and its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such as 9-point high pass filtering, empirical orthogonal function (EOF) analysis, composite analysis and other statistical diagnosis, etc. It is concluded as follows: (1) EOF analysis of SLP in the East Asia-West Pacific region shows the existence of the zonal dipole oscillation mode (APD) between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity index of EASM. (2) EOF analysis of GHT anomalies at 500 hPa in the East Asia-West Pacific region shows that the first EOF mode is characterized with an obvious meridional East Asian pattern (EAP), and EAP index can also be used as an EASM intensity index. (3) The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa (or 850 hPa). The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient of −0.23, which passes the confidence test at 0.10 level. (4) Both APD and EAP indexes are closely correlated with precipitation during flood-prone season in China and precipitation rate over the East Asia-West Pacific region. The significant correlation area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern Japan, and the former is a positive correlation and the latter is a negative one. Foundation: Cooperative Project funded by the Ministry of Science and Technology of the People’s Republic of China, No.2007DFB20210; National Natural Science Foundation of China, No.90502003; JICA China-Japan Technical Cooperative Project “China-Japanese Cooperative Research Center on Meteorological Disasters”. Author: Yu Shuqiu, Associate Professor, specialized in climate and climate change.  相似文献   

15.
SOFTWARE REVIEWS     
software reviews are in this article BMDP/PC CONCEPTS COMPUTERIZED ATLAS EVALUATION OF ALTERNATE PROPOSALS (EAP) EXTRA: EXPRESS TRANSIT ANALYSIS MATC CAD MOTORS TRANSPORTATION PACKAGE PCMAP: Thematic Mapping Software for the IBM Personal Computer, Version 2.3 PLACE TRANPLAN . US-ATLAS  相似文献   

16.
For modeling the topological relations between spatial objects, the concepts of a bound on the intersection of the boundary and interior, and the boundary and exterior are defined in this paper based on the newly developed computational fuzzy topology. Furthermore, the qualitative measures for the intersections are specified based on the α‐cut induced fuzzy topology, which are (Aα∧?A)(x)<1?α and ((Ac)α∧?A)(x)<1?α. In other words, the intersection of the interior and boundary or boundary and exterior are always bounded by 1?α, where α is a value of a level cutting. Specifically, the following areas are covered: (a) the homeomorphic invariants of the fuzzy topology; (b) a definition of the connectivity of the newly developed fuzzy topology; (c) a model of the fuzzy topological relations between simple fuzzy regions in GIS; and (d) the quantitative values of topological relations can be calculated.  相似文献   

17.
用溶胶 -凝胶法制备了 L i Mx Mn2 - x O4( M=Cr、Al;x≤ 0 .2 )尖晶石相锂离子电池阴极材料。SEM表面观测显示材料的晶形好 ,粒度均匀 ,粒径小于 0 .5微米。电化学测试表明 ,低水平量 ( 0 .0 2≤ x≤ 0 .0 5 )的 Cr、Al掺杂材料初始容量稍有降低 ,但却较大地改善了循环性能。在 L i Mx Mn2 - x O4中 ,掺 Al降低了 L i+、Mn3+占位的无序度 ;Cr3+和 Al3+取代了其中的部分 Mn3+ ,占据八面体位 ( 16 d) ,抑制了 Jahn-Teller效应 ,增强了尖晶石骨架的稳定性 ,提高了其电化学性能。在 3.0~ 4.3V的充放电过程中 ,材料中的 Cr、Al都保持 +3价不变 ,不发生氧化还原  相似文献   

18.
We investigated the influence of deep forced temperature convection on aeration of the bottom water layer in the pelagic zone of Baikal. Temperature T (± 0.002°C) and oxygen O2 concentration (± 0.01 mg/L) were measured by using the SBE-25 probe with the SBE-43 oxygen sensor in May-July 2006?2007 and 2009?2013. Oxygen input into the bottom layer with cold intrusions was determined for 79 cases. The study revealed a quantitative correlation between the heat deficit and the rise in oxygen content in the bottom layer during cold intrusions. This correlation was used to reconstruct the values of intrusion aeration of the bottom layer during 1993?2005. It is ascertained that the intrusion-caused 2006?2013-average oxygen input into Baikal’s bottom layer is virtually close to the annual oxygen demand for oxidation processes in the water column and bottom sediments. In the southern and middle parts of Baikal, intrusion-caused input of oxygen corresponds to a higher rate of its demand (4.5?4.6x10-4 mg/L per day). A slight increase in oxygen concentration was detected in the bottom layer of the South and Middle Baikal and a slight decrease in the bottom layer of North Baikal during 1993?2013.  相似文献   

19.
陈世发 《地理科学》2016,36(10):1573-1580
选取1951~2013年韶关市分月降雨量数据,采用月降雨侵蚀力模型计算降雨侵蚀力,分析ENSO(厄尔尼诺-南方涛动)对韶关市降雨侵蚀力的影响。研究表明: 韶关市降雨侵蚀力年际变化和年内变化较大,总体呈现波动上升趋势;降雨侵蚀力与赤道太平洋SST距平值呈现极显著相关,降雨侵蚀力随SST距平值增加呈现先增加后递减的趋势。ENSO冷暖事件发生时降雨侵蚀力较小,在其它土壤侵蚀因素不变的条件下,此时期的土壤侵蚀相对较轻;降雨侵蚀力与SOI存在显著相关,降雨侵蚀力随着SOI增加而减小; 降雨侵蚀力与MEI呈现极显著的正相关关系。  相似文献   

20.
汶川地震在山区引发大量崩塌、滑坡,形成大量的固体松散碎屑物质堆积在沟谷内(CLCAR,崩滑碎屑区),使得地震山区泥石流活动性增强。以岷江上游四川省汶川县银杏乡、映秀镇的15条泥石流沟的SPOT遥感影像为基础,利用GIS技术对CLCAR空间分布进行分析。建立CLCAR与流域高程、主沟侧距和沟口纵距的分布函数T(x)、M(x)和G(x),对CLCAR的空间分布特征进行描述;并计算其积分(DT、DM和DG)作为CLCAR空间分布特征的定量化参数。结果表明,函数T(x)、M(x)和G(x)能够较全面描述CLCAR的空间分布特征,DT、DM和DG能够作为CLCAR空间分布特征的定量化参数。泥石流沟谷内CLCAR的空间分布对泥石流的形成及规模具有一定的影响;在对灾区泥石流研究时有必要考虑泥石流沟内CLCAR空间分布特征。  相似文献   

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