吡虫啉在土壤中的降解动力学研究

在实验室条件下，研究了吡虫啉在4种土壤中的降解动态。结果发现，吡虫啉在浙江土壤中降解最快T0.5为10．3d，在江西红壤中降解最慢T0.5为12．9d。土壤有机质含量和农药浓度对吡虫啉在土壤中降解有一定影响，土壤有机质含量越高降解越快，反之亦然。此外微生物对吡虫啉在土壤中的降解起了主要作用。     

高效液相色谱测定吡虫啉的残留研究

采用高效液相色谱测定吡虫啉的残留量，研究了吡虫啉在不同提取方法下于稻杆和土壤中的回收率并研究其消解动态。试验结果表明：稻杆中有用二氯甲烷振荡提取法测定吡虫啉回收率可达77.66%－93.62%；土壤中采用甲醇索氏提取法回收率为82.22%-90.89%，变异系数分别为：0.31%-1.93%，1.33%-2.85%；吡虫啉在稻杆和土壤中的半衰期分别为4.9d，5.6d。     

土壤中吡虫啉残留量的HPLC测定方法

本文介绍了用高效液相色谱法测定稻田土壤中微量吡虫啉农药残留量的方法,样品经民国腈超声提取后,用反相液相色谱一紫外法测定,方法灵敏、快速、简单、回收率高。     

70%吡虫啉水分散剂防治水稻二化螟效果的探讨

选用70%吡虫啉水分散剂进行不同剂量防治水稻二化螟的试验,其结果表明70%吡虫啉水分散剂防治水稻二化螟,使用剂量不同,而效果相差很大。从药效和经济角度考虑,推荐施用量为45~60g/hm2,施药时注意水稻植株要均匀着药。同时,对供试作物水稻施用安全。     

超声波降解法对壳聚糖结构的影响研究

本文以天然大分子量壳聚糖为原料,利用超声波降解法制备不同分子量大小的低聚壳聚糖,并采用红外光谱仪分析各分子量大小的低聚壳聚糖,来探讨超声波对壳聚糖结构的影响,并确定超声波降解法的最大超声功率。结果表明,随着超声功率的增加,降解后对壳聚糖的结构的影响也逐渐增加,并确定了最大超声功率不超过550W。     

蔬菜中残留吡虫啉的提取净化和分析方法

文中系统综述近年来蔬菜中残留吡虫啉的提取和纯化以及分析方法,所遴选的这些方法具有简便、快速、准确等特点,各项技术指标均能满足残留检测的要求。     

光合细菌对马拉硫磷降解特性的研究

通过利用3因素3水平L9(33)的正交实验,研究了光合细菌对马拉硫磷的降解特性,结果表明,降解条件为pH7.0、温度30.C、接种量为108个/mL,180 rmin-1摇床培养时,光合细菌菌株对马拉硫磷的降解率可达90％左右.     

聚碳酸脂的热降解性能研究

本文采用TG方法研究了国内外五种PC在空气和N2中的热稳定性,采用动态FTIR方法探讨了热氧降解机理,并以TG方法计算了热降解动力学参数。结果表明,试样的平均分子量越高．分布越窄,端基活性越小,含量越少,分解温度越高。主链酯基的水解为其热氧降解的主要机理。Doyle－Ozawa积分法所得热降解活化能为117.5kJ／mol,幂前因子为1．11×107min(－1)。     

臭氧降解水中农药的试验研究

目的 评价臭氧对水中农药的降解率，并对降解副产物进行定性分析。方法将臭氧通入水中20min，检测臭氧对水中农药的降解率及副产物。结果通臭氧20min的去离子水中，臭氧的浓度为0．24mg／L；敌敌畏、乐果、对硫磷和甲胺磷降解率分别为97．6％、45．2％、40．2％和34．3％。乐果副产物氧乐果，对硫磷的副产物：0，0-二乙基0-（4-硝基苯基）磷酸酯。结论臭氧可以降解水中的4种有机磷农药．但会产生毒性更高的降解产物。     

弹性联轴器对柴油机输出转矩不均匀性衰减研究

从理论和试验两方面，研究四种弹性联轴器对柴油机输出转矩不均匀性的衰减效果及衰减规律。主要分析联轴器的扭转刚度和输入转速对柴油机输出转矩不均匀性的影响，为选择和改进弹性联轴器提供科学依据。     

氟化镁窗口氘灯真空辐射衰减特性研究

对氟化镁材料窗口、紫外-真空紫外波段辐射传递标准光源氘灯的真空辐射衰减机理进行了分析。在此基础上，研制了液氮制冷屏装置来抑制氘灯衰减。建立了氘灯真空辐射特性测试研究系统，利用该系统对液氮制冷屏装置的有效性进行了考察。测试结果表明，在160-300nm波段，氘灯平均衰减率可由原来的7%/h下降为1%/h。液氮制冷屏装置能十分有效的抑制氟化镁窗口氘灯在真空环境下的辐射衰减。     

The effects of pH on the degradation of isothiazolone biocides

In order to measure the effective lifetime and understand the mechanism of degradation, the stability of the active component, 5-chloro-2-methyl-4-isothiazolin-3-one in Kathon 886 MW and Kathon MWC biocides was investigated in both acidic and alkaline solutions. For kinetic data at different pH levels, the concentration of the chlorinated component was measured at regular intervals using reversed-phase liquid chromatography. It was found that the biocides are stable in acidic media. However, the active component undergoes degradation in alkaline solutions, and the rate of degradation is faster with an increase in pH. The first-order rate constant and half-life values for the degradation of the active component in the pH range of 8.5 to 10 were determined. The typical half-life values were found to be 47, 23, 3.3 and 2 days in media of pH 8.5, 9.0, 9.6 and 10, respectively. A high stability in acidic medium, and a linear relationship between hydroxyl ion concentration and first-order rate constant in the alkaline range, suggest that chemical degradation of Kathon biocides results from hydrolysis of the chlorinated isothiazolone.     

基于遗传算法的退化试验优化设计

在基于退化试验数据的可靠性研究中,如何能在试验资源有限的条件下获得较准确的可靠性评估结果,是退化试验方案设计首要解决的一个问题。以某国产航空液压泵的退化试验方案设计为例,推导并建立了p阶分位寿命分布的方差最小的优化目标函数,以试验预算费用为限定条件,采用遗传算法进行了优化算法设计,并对服从线性退化模型的一批试验样品进行了算例分析。结果表明:与传统优化算法相比,该方法具有运算量小、求解效率高、容易得到全局最优解的特点。     

Experimental study on the life prediction of servo motors through model-based system degradation assessment and accelerated degradation testing

The advent of smart factories has resulted in the frequent utilization of industrial robots within factories to increase production automation and efficiency. Due to the increase in the number of industrial robots, it has become more important to prevent any unexpected breakdowns of the factory. As a result, the lifespan prediction of machinery has become a crucial factor because such failures can be directly associated with factory productivity resulting in significant losses. Most of the failures occur within one of the core components of the robot arm, the servo motor, and thus we will focus on the analysis of the servo motor in this study. However, sensor attachment to such equipment is considered difficult due to the dynamic movement of the robot arm, meaning that internal instrumentation should be utilized during analysis. In addition, no definite measure to determine the degradation of the motor exists, and thus a new degradation index is proposed in this study. Therefore, in this study, the lifespan of the servo motor will be estimated through accelerated degradation testing methods based on a new system degradation assessment method, which estimates the fault of the system using observer-based residuals with encoder data obtained from internal instrumentation.     

Model of scuffing based on the vulnerability of an elastohydrodynamic oil film to chemical degradation catalyzed by the contacting surfaces

A model of scuffing is developed based on the premise that metallic surfaces can catalyze degradation of the lubricant film in situ. A failure mechanism for elastohydrodynamic films based on rapid decomposition of mineral and synthetic oils involving chemical reaction between entrapped oil and the containing surfaces is proposed. It is suggested that this destruction of the elastohydrodynamic oil film allows adhesion between nascent metal of opposing surfaces in the contact which in turn causes scuffing. Suppression of scuffing by the application of coatings that do not catalyze the oil decomposition and by the action of some lubricant additives which may block the catalytic effect of metallic surfaces is discussed. Effect of solid lubricant films and contaminant layers on scuffing is also described.     

基于系统稳定性的可靠性分析研究

从控制理论的角度出发，认为“可靠性”本质上是产品功能的稳定性问题，同时给出了基于稳定性的产品可靠性分析的定量方法与定性方法。进一步结合机械可靠性设计理论作了具体分析。