有机中微肥的生产及其应用前景

我国中低产田面积占总耕地面积70%以上,其中大部分存在有机质和中微量元素缺乏和肥料利用率低的问题。为防止中微量元素施入土壤后被固定而失效,提出利用废弃资源,生产有机中微肥(如氨基酸、木质素磺酸、腐植酸中微肥等),其生产成本比EDTA螯合中微肥低,并简要介绍了各种有机中微肥的生产工艺过程。只要做到测土施肥,有针对性加入有机中微肥,即可达到提高作物产量、品质,提高肥料利用率,提高土壤肥力的良好效果。     

ICP-MS法测定陶瓷容器中重金属元素的研究

采用电感耦合等离子体—质谱(ICP—MS)法同时测定了陶瓷容器中重金属元素PB、CA、Cr、Ni，对影响其测量的各种因素进行了较为详细的研究，确定了实验的最佳测定条件。结果表明，方法的检出限为0．002—0．008μg/L，回收率为90．0％-110．0％，RSD小于9．21％。该法准确、快速、简便，应用于陶瓷容器中重金属元素的测定，结果满意。     

面向信息检索的藏文文本索引策略研究

互联网文本数量持续爆炸式增长,用户通过互联网查找信息变得更加困难,响应时间得不到满足。针对藏文本身的语言学特点,探讨一种面向信息搜索的藏文文本索引建立策略,建立一种高效的藏文文本索引,以提高藏文信息检索速度。     

FAST LINEAR ESTIMATION METHODS FOR VECTOR AUTOREGRESSIVE MOVING-AVERAGE MODELS

Abstract. Three linear methods for estimating parameter values of vector auto-regressive moving-average (VARMA) models which are in general at least an order of magnitude faster than maximum likelihood estimation are developed in this paper. Simulation results for different model structures with varying numbers of component series and observations suggest that the accuracy of these procedures is in most cases comparable with maximum likelihood estimation. Procedures for estimating parameter standard error are also discussed and used for identification of nonzero elements in the VARMA polynomial structures. These methods can also be used to establish the order of the VARMA structure. We note, however, that the primary purpose of these estimates is to generate initial estimates for the nonzero parameters in order to reduce subsequent computational time of more efficient estimation procedures such as exact maximum likelihood.     

因特网上化学化工资源的开发及利用

随着计算机网络技术的迅速发展，利用Internet游览和获取化学信息已成为查阅化学化工文献最重要的方法之一，在化学化工工作者中普及Intemet网上查阅各类化学化工信息和获取这些资源的方法非常重要。本文详细介绍了因特网上化学化工信息的检索方法，包括搜索引擎和信息导航系统、化学化工专业网站、数据库、专利、网上图书馆及电子期刊、化学化工软件、化学仪器及化学试剂供应商的网站，并提供了一些非常实用的专业站点。     

ICP-AES法测定精制盐水中的微量元素

采用电感耦合等离子体发射光谱法测定二次精制盐水中Ca、Mg、Sr、Fe、Ba、S i等微量元素含量。方法简便、快速、精密度高,结果准确可靠。     

Effect of vermicomposting on the transformation of some trace elements in fly ash

One major constraint of the agricultural uses of fly ash (FA) is the low availability of different plant nutrients despite their high occurrence in the total amount. However, degrading FA through increased microbial activity can improve the availability of these nutrients substantially. It has been found that intestines of epigeic earthworms contain a high concentration of different microorganisms. Therefore, in the present study we addressed the effects of vermicomposting technology on the solubility of some micronutrient cations (Fe, Mn, Cu, and Zn) and some heavy metals (Pb, Cd, and Cr) in different combinations of fly ash and organic matter, applied in the form of cow dung (CD). Various combinations of FA and CD were treated with and without an epigeic earthworm (Eisenia fetida) and the solubility of different trace elements in the treatments were estimated periodically. The results revealed that the inclusion of epigeic earthworm Eisenia fetida in different combinations of fly ash and cow dung converted a considerable amount of the micronutrients into bio-available forms. On the other hand, the solubility of heavy metals tended to be reduced by the microorganisms, presumably by formation of some organo-metallic complex. Application of these vermicomposted FA and CD combinations to a red lateritic soil was found to improve the soluble Fe, Mn, Cu, and Zn status of the soil. Furthermore, the use of vermicomposted FA and CD (1:1) in potato cultivation demonstrated that use of this mixture at 10 ton per hectare (t ha⁻¹; fresh weight) was able to compensate 80% of the recommended NPK fertiliser, along with farm yard manure application, without compromising the crop yield.     

MIKE21模型在南新联圩洪水模拟中的应用

为了分析江西省南新联圩防洪保护区在圩提溃决后洪水在区内的演进过程,根据南新联圩防洪保护区周围湖泊、河流及圩区情况,建立了模拟保护区内洪水演进的MIKE21模型。分别采用2010年和2012年实测洪水资料对模型进行率定和验证,结果表明模型具有较高的模拟精度。在赣江50 a一遇洪水叠加湖口22.5 m洪水位(1954年型)的工况下,利用所建立的模型对防洪保护区内的淹没水深、流速和洪水演进过程等进行计算分析,获得了南新联圩防洪保护区发生溃堤后的受灾发展情况。研究成果可为南新联圩防洪预警及时发布、转移财产、逃生避险等提供技术支撑。