地球气测量的若干问题   总被引：6，自引：0，他引：6  

卢荫庥  白金峰 《物探与化探》1999,23(6):401-407

从分析测试的角度,就影响地球气测量新技术推广应用的原因进行了讨论.认为集气材料的纯度和分析测试中使用试剂的纯度,以及在野外采气作业与室内分析时可能引起的污染是影响这一技术推广的关键所在.  相似文献   

棉铃虫的气象预测初探   总被引：3，自引：0，他引：3  

王瑞芳  任鹤麒 《气象科学》1999,(1)

通过对历史资料的分析研究,寻找出与棉铃虫发生发展有密切关系的气象条件及生物因子,建立各代棉铃虫始发期及发生程度的气象预测模式。对1994、1995年的各代棉铃虫发生情况进行了预测检验,效果良好。1996、1997年投入业务预报服务,预报与实际发生情况相符,为棉铃虫的有效防治提供了科学依据。  相似文献   

A STUDY ON RATIONAL LOCATION OF THE COTTON PRODUCTION IN CHINA     

祝卓 《中国地理科学(英文版)》1991,1(2):129-140

Cotton is the leading cash crop in China. The cotton sown area accounts for about 30per cent of the total sown area of all the various cash crops. It is the main material used in the textile industry in China. More than 95per cent of textile materials were cotton during the 1950s; and it still occupies 80per cent at present. There are some problems concerning rational location of cotton production in China. In order to solve the problems existing in civil cotton production and supply, in view of strategy, a number of cotton production bases must be selected and built step by step in a planned way. The location of cotton production should be adjusted progressively in accordance with the existing problems. The existing cotton production regions should be consolidated and improved. The cotton production region of the middle and lower reaches of the Huanghe River should be renewed quichly to make it become the largest stable and high-yield cotton preduction region. In the regions with suitable natural condi  相似文献   

Determination of total selenium in geological samples by HG-AFS after concentration with thiol cotton fiber     

FAN Haifeng WEN Hanjie HU Ruizhong CHANG Bin 《中国地球化学学报》2008,27(1):90-96

Standard reference material and different geological samples were dissolved by system A （the mixture of nitric and perchloric acids） and system B （mixture of nitric, perchloric and hydrofluoric acids）, and total Se in all samples was measured by hydride-generation atomic fluorescence spectrometry （HG-AFS） after concentration with thiol cotton fiber （TCF）. The analytical results obtained by the two digestion method are in good agreement （within the limit of errors） for most of the samples, particularly for those having recommended values. The Se concentrations determined by the two methods are of no difference, and the correlation coefficient is 0.9986; the relative standard deviation （RSD） for the determination of 0.04 μg/g Se is 10.2%. The recovery rates of systems A and B by the standard-addition method were 96%-106% and 99%-104%, respectively.  相似文献   

巯基棉分离富集ICP-AES法测定高盐冶金废水中痕量铅镉铜银   总被引：3，自引：1，他引：2  

张宁  郭秀平  李星  申玉民  姜云军  安彩秀  薛志坤 《岩矿测试》2014,33(4):551-555

矿山企业的冶金废水含有多种污染环境的金属元素,必须经过化学沉淀法处理达标后排放。冶金废水经化学沉淀后引入了大量盐分,使得金属元素含量变得极低给分析测试造成困难。针对此类高盐冶金废水,本文采用巯基棉分离富集其中的金属元素,建立了运用电感耦合等离子体光谱(ICP-AES)测定铅、镉、铜、银的分析方法。通过优化实验表明,巯基棉可有效地分离实际样品中大量存在的硫酸根离子和钠离子基体,富集待测元素的效果显著,硫酸根离子和钠离子回收率均小于0.05%,待测元素的回收率在88.7%~113.0%之间。实验条件方面,待测溶液的pH值对巯基棉吸附有较大的影响,使用巯基棉富集前应将溶液调节至适宜的pH值;待测溶液在富集柱中的流速和洗脱剂盐酸的浓度对分离富集效果也有一定的影响。在最佳实验条件下,本法回收率为95.0%~102.0%,精密度(RSD)为3.1%~9.4%,方法快速简便、准确度高,能够满足冶金废水中痕量金属元素的检测需求。  相似文献   

Evaluating a nonionic surfactant as a tool to improve water availability in irrigated cotton     

D. G. Sullivan  R. C. Nuti  C. C. Truman 《水文研究》2009,23(16):2326-2334

Nonionic surfactants have been well researched in turf grass environments as a tool to ameliorate water‐repellant conditions. However, few studies have evaluated the risks and benefits of nonionic surfactant applications in row‐crop agricultural systems. The objective of this study was to evaluate the impact of a nonionic surfactant on cotton (Gossypium hirsutum L.) production on a Faceville loamy sand (fine, kaolinitic thermic Typic Kandiudult) in the coastal plain region of Georgia. The experiment consisted of two components: (1) on‐site rainfall simulation and (2) agronomic cotton field trials. Treatments were designed to test the impact of rate and frequency of surfactant applications using six combinations of application rates and timings. For the rainfall simulation component, only the control (0·0 L ha^?1) and high rate (0·51 L ha^?1) of surfactant applications were evaluated. During the field trial, soil water content, cotton stand counts, and yield were measured. Rainfall simulations showed that the addition of surfactant increased runoff, decreased infiltration, and promoted surface sealing. Despite the demonstrated potential for water loss, agronomic field trials showed that crop yields were not significantly different between surfactant‐treated and untreated plots. No differences in soil water content were observed between treatments at 5 and 15 cm depths; however, soil water content was significantly higher in untreated control plots at the 30 cm depth. Data demonstrate the need for clarification of soil physical/chemical properties and surfactant interactions that may lend themselves to the creation of surface seals and how these seals impact soil/water conservation and crop yield. Published in 2009 by John Wiley & Sons, Ltd.  相似文献   

敦煌气候条件及对棉花产量因素的影响     

王秀琴  吴婷芳 《干旱气象》2014,32(6):1003-1006

甘肃敦煌地区气候条件虽然适宜棉花生长,但热量条件处于棉花正常生长适宜指标的下线,对棉花的产量和质量具有较大影响。利用敦煌市国家基准气象观测站1983~2012年农业气象观测资料,统计分析了敦煌棉花全生育期气象条件对棉花的株铃数、单铃重及僵烂铃率、蕾铃脱落率及产量的影响。结果表明：棉花花蕾期气温、花后热量和花期气温、裂铃吐絮阶段灌水量是造成棉花僵烂铃和蕾铃脱落的主要原因。花铃期的平均气温越高,热量越充足,越有利于棉铃数的增加;7月上旬至8月中旬夜温不足降低了棉株矿物质和贮存物的积累速率,导致花蕾及胚珠发育不良,单铃胚珠数减少;盛夏7月中旬高温造成棉铃代谢紊乱,导致单铃不孕,造成株铃数不足和单铃重下降,进而影响棉花产量。  相似文献   

大叶藻海草床的生态恢复: 根茎棉线绑石移植法及其效果     

刘鹏  周毅  刘炳舰  刘旭佳  张晓梅  杨红生 《海洋科学》2013,37(10):1-8

于2009年和2010年在青岛汇泉湾用根茎棉线绑石法进行大叶藻(Zostera marina L.)移植, 并于2012年4月20日至11月19日对移植大叶藻的生长情况进行观察(包括形态学变化、密度、茎枝高度、地上生物量、底质粒径几个方面)。观察期间水温为7.8～26.1℃。结果显示, 移植底质可定性为粉砂质;移植大叶藻的有性繁殖期为2012年4～8月; 无性繁殖在秋季达到高峰; 密度在6月和9月分别高达411茎枝/m²和481茎枝/m²; 高度与地上生物量的最大值出现在6～7 份。与2009年青岛湾天然大叶藻进行比较后可以发现, 移植大叶藻的高度、地上生物量及其季节变化与天然大叶藻基本保持一致,说明移植大叶藻的生长状况良好, 同时说明根茎棉线绑石法是一种高效且实用的海草床生态恢复方法。  相似文献   

抗虫棉早衰气象条件分析与防御对策     

武文安  李业民  马焕香  郝新  莫瑶 《气象科技》2010,38(1):125-128

利用山东省惠民县气象局1988～2007年(抗虫棉1998～2007年,常规棉1988～1997年)观测资料,对温度和降水影响棉花早衰问题进行了分析,得出5～7月平均气温和秋桃数呈明显负相关关系,5～7月平均气温越高,秋桃数越少,棉花早衰越严重;6月中旬至7月中旬降水偏少,干旱易形成老小苗,棉花发生早衰;8月中旬至9月上旬降水偏少、秋桃偏少,造成棉花早衰。从气象方面提出了抗虫棉早衰的防御对策。  相似文献   

晋南地区典型盐碱地棉田的NO排放特征   总被引：4，自引：1，他引：3  

李明  梁旺国  郑循华  杨治平  郑普山  陈玉成  陈德立 《气候与环境研究》2009,14(3):318-328

NO是一种主要的大气污染物,施肥农田是大气N0的第二大排放源,农田N0减排有利于减轻空气污染.但农田N0减排措施的制定需要以排放特征和清单研究为基础.本研究采用静态箱自动采样一化学发光在线实时测定方法,对晋南地区典型灌溉盐碱地棉田(实验期间以纯氮计的氮肥施用量为66. kg·hm-2·a-1)的NO排放进行了全天候周年连续观测.结果表明:对于该棉田的NO排放测定,提高观测频率比增加空间重复(增加采样箱)更重要;年度N0排放表现出春夏高、秋冬低的季节变化特点;晴天普遍发生着与温度同步的日间极大值单峰型日变化,且大多数情况下的NO日排放极大值比5 cm深度的土壤温度极大值提前大约3 h;NO-N背景排放率约为0.64 kg·hm-2·a-1,肥料氮的年NO-N直接排放系数为0.32%±0.09%.这些结果揭示了盐碱地棉田NO排放的一些重要特征,并为编制农田NO排放清单提供了排放系数实测数据.  相似文献