热分析法研究水稻花药发育过程及其动力学

植物花药发育是植物个体发育过程中的一个重要组成部分。在此过程中,花药物质和组成不断变化,呈现出显著的动态过程。关于花药发育过程中物质和组成变化的研究,人们已经做了很多工作。但未见用热分析法研究水稻花药发育过程及其动力学的报道。本文用热分析法研究了不同花粉育期野败型和红莲型两类水稻保持系可育花药的热分解过程,测定了花粉不同育期可育花药的热重/差热(TG/DTA)及其差示扫描量热(DSC)曲线,获得了相应的热力学参数,分析了它们在不同时期的热分解规律以及发育过程中花药物质变化与其不同育期的关系,建立了发育过程中水稻花药干物质增长的动力学模型,并计算了它们的表观动力学参数。     

Cochliobolus miyabeanus湿热杀菌研究及TDT模型的建立

Ｃｏｃｈｌｉｏｂｏｌｕｓｍｉｙａｂｅａｎｕｓ在７５℃,相对湿度６５％、７０％、７５％、８０％、８５％下和８０℃,相对湿度５５％、６５％、７０％、７５％、８０％下进行不同时间的杀菌试验．在此基础上,用固定温度,以相对湿度同杀菌时间建立回归关系,并用等差法建立杀菌时间模型和以焓增量建立湿热杀菌时间模型,并对两种方法进行了比较     

马来海松酸聚酯氨基树脂耐热性研究

以马来海松酸和线性小分子二醇为原料,合成马来海松酸聚酯多元醇,再用氨基树脂交联,制备马来海松酸聚酯基树脂。利用热重分析,讨论了了不同原料种类及配比对树脂耐热性的影响。研究结果表明,马来海松酸聚酯多元醇和氨基树脂以及它们的配比直接最终树脂的耐热性。     

橡胶木胶合板阻燃技术研究 Ⅳ.橡胶木胶合板的燃烧性质及热性质

通过对橡胶木胶合板与水曲柳胶合板、杨木胶合板、椴木胶合板的点着性、燃烧释热性、火焰传播性、发烟性以及热重曲线的对比,了解橡胶木胶合板的燃烧性质和热性质,并进一步探讨ＷＦＲ作为橡胶木胶合板阻燃剂的处理效果。     

动力负熵场及其在短期天气预报中的应用

把纬圈气流虚拟平衡态原理具体应用到短期预报中,因时效短的缘故,决定了虚拟平衡态应在低层大气中寻找,倘若时效达到一定天数,则平衡态应在中层大气中定义。按照涡动原理计算出动力负熵值,由动力负熵值构成动力负熵场,其由正熵区,负熵区、０值线三部分组成,正熵区为无降水区,负熵区又分为负熵有效区和负熵无效区,前者为未来的降水区域,降水强度与负熵中心值和梯度的大小成正比。     

基于非稳态热探针法的稻谷导热系数的测定

根据传热理论,导出探针法测定稻谷导热系数的数学模型。通过测定探针的升温速率,由上述数学模型计算出不同含水率稻谷的导热系数。实验结果表明,在常温下,产于我国南方地区的短粒型稻谷的导热系数随含水率的增加而增大。回归分析表明,短粒型稻谷的导热系数与含水率之间为线性关系。     

基于圆筒瞬态热流法的短粒型稻谷导温系数的测定

根据圆筒瞬态热流法的理论模型 ,利用自制的导温系数测定仪 ,对产于我国南方地区的短粒型稻谷的导温系数进行了测定 ,并研究了含水率对稻谷导温系数的影响。结果显示 ,在 2 0～ 80℃的温度范围内 ,对于含水率在 6 .4 8%～ 19.8%的稻谷 ,其导温系数与含水率之间不具有线性相关性。置信度为 95 %时 ,短粒型稻谷的导温系数为 (0 .14 6± 0 .0 0 3)μm2 / s。     

汽车发动机尾气利用的现状与展望

对汽车尾气构成及其利用空间进行了分析。着重介绍了汽车尾气在涡轮增压、制冷技术等方面的应用。在此基础上探讨了技术、工艺和材料等方面对汽车尾气利用的影响以及国内、外汽车尾气利用技术的发展趋势,并指出了尾气利用的特点和发展的方向。     

Fate of Endosulfan in Cotton Soil under Sub-tropical Conditions of Northern India

Terrestrial field studies were conducted with endosulfan during the 1989–90 Kharif season in bare cotton soil, to investigate the fate of endosulfan and its downward movement under sub-tropical conditions of northern India. Field experiments consisted of spray application of endosulfan at 875 g ha^-1 42 and 63 days after the assumed date of sowing in two separate treatments. Soil samples drawn periodically from different depths were analysed by GC-ECD (Ni⁶³) for endosulfan and its breakdown products. Dissipation of the total endosulfan residues occurred to an extent of 92–97% in the first four-week period and by about 99% in 238 days in two distinct phases in first-order kinetics. Residue half life (T_1/2) varied from 39 to 42 days. The parent compound metabolized to endosulfan-diol and endosulfan sulfate. Endosulfan-diol remained confined in the upper 5-cm layer and dissipated completely in 28 days whereas endosulfan sulfate was first detectable seven days after treatment and persisted until the end of the experiment, remaining confined in the upper 0–10 cm soil layer. The β-isomer also did not leach down beyond 10 cm depth. © 1997 SCI.     

Persistence of tebufenozide in aquatic ecosystems under laboratory and field conditions

The persistence and dissipation behaviour of tebufenozide, an ecdysone agonist, were investigated: (1) under laboratory conditions in aquatic models set up in glass aquaria, and (2) under field conditions in in-situ aquatic enclosures deployed in a mixed-wood boreal forest lake. Two models were set up in the laboratory study (Study I), which was conducted at constant conditions of temperature, water pH and photoperiod. In Model I, partitioning of tebufenozide from sediment, treated at a concentration of 1400 μg kg^-1, into untreated water was examined. The results showed that the chemical moved very little from the treated sediment into water. The concentration in sediment and water decreased gradually during the 90-day incubation period. Tebufenozide disappeared faster from the top layer of sediment than from the middle and bottom layers. The half-lives of disappearance were 64 days for the top layer but >90 days for the middle and bottom layers respectively. In Model II, partitioning from water, treated at a concentration of 350 μg litre^-1, into untreated sediment was investigated. The results showed that the chemical moved from treated water into sediment due to adsorption. Little vertical downward movement of the adsorbed residues from the top layer of sediment occurred into layers beneath. The adsorbed residues were also not released readily back into water. The concentration in water and sediment decreased gradually during the 90-day incubation period. The half-life of dissipation from water was 67 days. The field microcosm study (Study II), conducted under fluctuating conditions of temperature, water pH and photoperiod, involved application of tebufenozide onto aquatic enclosures at four concentrations of 0·05, 0·10, 0·26 and 0·5 mg litre^-1. This study also showed that the chemical moved downwards from the applied location and was adsorbed onto sediment. The chemical persisted longer in Study II than in Study I. Tebufenozide, being photo-labile, probably degraded faster after constant exposure to light in Study I than after exposure to fluctuating light in Study II. At 90 days after treatment in Study I, only about 55% of the applied material persisted in the sediment, and there was little accumulation. In Study II, the material not only persisted but also was accumulated in the sediment, since at 92 days post-treatment the residues were about 25 times higher than the applied concentration level. Residues in water also decreased more rapidly in Study I than in Study II, because the concentration at 90 days post-treatment was about 41% of the applied value. In Study II, however, about 65% of the applied chemical persisted in water at 92 days post-treatment. While the long persistence of tebufenozide in both the laboratory and field studies was attributable to its low vapour pressure, low water solubility, high octanol/water partition coefficient etc., the differences in the persistence characteristics observed in the two studies were due to the fluctuating environmental conditions and water pH encountered in the field study, compared with the constant environmental conditions and water pH utilized in the laboratory study. © 1997 SCI.