拟除虫菊酯综述

拟除虫菊酯类杀虫剂是70年代中期开始大量使用的新型农药，是天然除虫菊酯的模拟物，生物降解性好，对环境影响小。由于不断地探索研究，通过引入新的基团进行分子结构优化和对同分异构体的组合、折分，至今已有50余只品种，相比天然菊酯杀虫活性最高的Ⅰ型菊酯，大部分高效、广谱、光稳定性好，可用于大田，农药用量可比常规药量低一个数量级或更少，而且品种众多，形成各具特色的产品类型。目前拟除虫菊酯占全球杀虫剂市场的20％，每年销售额约156000美元，95％以上用于农业治虫，主要是棉花、水果和蔬菜，少部分用于畜禽、公共卫生和家庭…     

拟除虫菊酯的研究进展

拟除虫菊酯是一类重要的合成杀虫剂,具有高效、广谱、低毒和能生物降解等特性。本文简要评述了拟除虫菊酯的研究进展。     

拟除虫菊酯的开发应用

本文主要介绍了一种重要合成杀虫剂－－拟除虫菊酯,并且分析了其发展与广泛的应用,并提出了建议。     

卤素拟除虫菊酯毒理学研究进展

含卤素拟除虫菊酯冈其高效、低毒、低残留而被广泛应用于农业生产及日常生活中.但其引起的毒理学问题也越来越受到人们的关注.综述了卤素拟除虫菊酯的神经毒性、生殖和基因毒性、生理生化毒性及联合毒性,并对其发展趋势进行了展望.对新型卤素拟除虫菊酯的研究开发具有指导意义.     

非羧酸酯类拟除虫菊酯研究进展

论述了非酯型拟除虫菊酯的研究进展 ,介绍了其结构特点、生物活性、研究现状、立体异构及抗性方面的内容。     

拟除虫菊酯及有机磷的交互抗性研究

醚菊酯的出现,是八十年代拟除虫菊酯类杀虫剂研究的新进展。它除保持了一般拟除虫菊酯的高效、安全、杀虫谱广的特点外,其突出的优点是,在化学结构上只含碳、氢、氧,在生物活性上表现鱼毒低,可以在水稻田使用,同时具有较好杀螨活性。我国自八十年代以来,在农业和卫生防疫方面,拟除虫菊酯的用量迅速增加,害虫产生抗性的种类也越来越多,且大多数常用拟除虫菊酯品种之间都有不同程度的交互抗性。直接影响着新拟除虫菊酯的引进、开发及推广应用。为全面了解醚菊酯与常用拟除虫杀酯、有机磷在抗药性方面     

拟除虫菊酯中间体合成工艺改进

一、前言拟除虫菊酯这类合成杀虫剂具有天然除虫菊酯的杀虫作用快,击倒力强,有广谱性,容易降解,对高等动物低毒性等多种特点,可以弥补天然除虫菊酯产量低、含量少、不耐光和热等缺陷,是比较理想的杀虫剂。间苯氧基苯     

Ceramic laminates with improved mechanical reliability by tailoring the porosity of the constituting layers

Two different ceramic laminates composed of porous alumina and alumina/zirconia layers were designed and produced in the present work. The two symmetrical architectures were selected whose fundamental difference is the presence on the surface of a porous layer in the first and a compact alumina/zirconia composite layer in the second. The residual stress profile and corresponding fracture toughness were tailored to promote the stable growth of surface defects prior to final failure to increase the mechanical reliability of the material. The laminates were realized by stacking together different green laminae (containing specific pore former content) in a specific order, thermo-compression and co-sintering. The results point out an important reduction of the strength scatter and a clear insensitivity to surface damage. It is also shown that the mechanical performances are strictly related to the specific architecture of the laminate, this allowing to tailor a priori the mechanical performances of the composite.     

表面活性剂在农药使用中的作用研究

水稻、小麦及苞菜等难以被药液润湿的植物,临界表面张力小,棉花、黄瓜等易被药液润湿的植物,临界表面张力大。用表面活性剂降低溶液的表面张力后,在水稻和苞菜上的持液量增加,但在棉花和豇豆上的持液量下降。测定的30种常规杀虫剂中,大多数药剂推荐剂量药液的表面张力介于水稻和棉花等作物之间,不利于增加在这些作物的持液量。     

Effect of substrate temperature on the microstructure and properties of thick plasma-sprayed YSZ TBCs

Thick (∼1.2 mm) thermal barrier coatings (TBCs) consisting of YSZ were deposited by plasma spraying. Spraying parameters were varied in a controlled manner to produce different microstructures. The effect of substrate temperature on the microstructural features and subsequently on the Young's modulus was investigated. In addition, the residual stresses in the coatings were estimated using a numerical model and they were related to the microstructural features observed. Results showed that crack segmentation density, residual stresses in the coatings and thus coating properties are strongly affected not only by the average substrate temperature during spraying but also the variations between the minimum and maximum substrate temperature.     

阿司匹林载药淀粉微球吸附性能的研究

以可溶性淀粉为原料,研究了淀粉微球在反相悬浮体系中对阿司匹林的吸附作用。探讨了交联剂用量、引发剂用量、反应时间及搅拌速度对微球药物吸附量的影响,并考察其体外释放情况。结果表明：当交联剂用量为12g/L,引发剂用量为3g/L时,60℃下中速搅拌2.0h,淀粉微球对阿司匹林有较大吸附作用。在酸性条件下,阿司匹林淀粉微球在8h内有较好释放,交联剂用量对释药速率有较大影响。     

立体连续传质塔板板上清液层高度实验研究

对立体连续传质塔板( LLC - Tray)的板上清液层高度进行了测量.结果表明:LLC -Tray板上清液层高度随液体流量的增加而增加,随堰高的增加而增大,气速对清液层高度的影响很小.     

热粘液中引入挥发性冷剂进行汽化冷却的传热研究

研究了热粘液中引入挥发性冷剂进行汽化冷却的传热过程。在一垂直圆形循环管中,引入冷剂酒精液滴于热浓糖溶液中,获得了糖液的汽化冷却曲线：分析了冷剂通入量对瞬间主体温度及容积传热速率的影响,并以“界面汽化热阱”的概念对传热机理进行了分析。冷剂在热粘液中汽化,是以泡滴的形态进行的。由于酒精与糖液是互溶的,在圆形管中对于泡滴的形态以及酒精与浓糖溶液间的界面难以观察清楚,因而设计了一套便于观察、拍照和分析的由两块玻璃板组成的窄缝且外侧带有保温夹套的实验设备(类似于Hele．Shaw盒)。在该设备中,对不互溶冷剂及可互溶冷剂在热浓糖溶液中汽化时形成泡滴的状态进行了比较,并分析了它们具有不同状态的原因。     

Studies on the evolution of asphaltene structure during hydroconversion of petroleum residues

The evolution of asphaltenes has been studied under hydroconversion conditions with an ebullated bed on a Buzurgan (Middle East) feedstock. A bench unit was used to produce effluents in residue conversion conditions ranging from 55 to 85 wt.%. In those conditions, asphaltene conversion ranged 62–89 wt.%. Asphaltenes from the feedstock and unconverted asphaltenes have been characterized using Size Exclusion Chromatography to evaluate asphaltene size, and ¹³C Nuclear Magnetic Resonance to evaluate the evolution of the average molecular structure parameters of asphaltenes. Results obtained were compared to results obtained at moderate residue conversion levels in a fixed bed.

The work clearly shows that unconverted asphaltene evolution is continuous. Unit size decreases with increasing conversion while the aromaticity of the asphaltenes increases due to dealkylation. Our results suggest that the remaining asphaltenes are dissociated in smaller aggregates around 50% conversion. Below this level, asphaltene evolution may be related to dissociation mechanisms. Above 50% conversion, the chemical structure of asphaltene units still significantly evolves through dealkylation mechanisms, leading to fairly condensed structures that remain at high conversion. Based on these results, an attempt was conducted to interpret the evolution of unconverted asphaltenes as a function of residue conversion level using a simple molecular reconstruction method.     

立体传质塔板相对液体提升量的计算

液体提升量是影响立体传质塔板(CTST)气液传质的条件有关.今分析了气液两相在帽罩内部的流动特点和能量分布状况,以立体传质塔板帽罩单元为研究系统,分析了气液两相带入和带出系统的能量以及通过帽罩时的能量损失,同时考虑帽罩结构和气液物性的影响,建立了立体传质塔板相对液体提升量数学模型.由于影响流动过程能量损失的因素比较复杂,将其表达为阻力系数的形式,并作为模型的参数.在直径600 mm的实验塔中对液体提升量进行了实验研究,确定了模型参数,并对模型进行了检验.结果表明,所建模型能够较好地反映立体传质塔板上液体的相对提升量.     

Surface roughness effects on the frequency tuning performance of a nanoelectromechanical resonator

Electrothermal heating is one of radio frequency tuning method in nanoelectromechanical resonators with magnetomotive transduction. This study confirmed that the surface roughness of the nanoresonator affects the electrothermal tuning performance under moderate conditions at room temperature. The effect of surface roughness on electrothermal tuning is complicated and involves interactions of mechanical and electrical properties. In addition, the electrothermal damping varied depending on the nanoscale molecular solid structure. These factors affect the signal-to-noise ratio, the effective stress of the beam, and the quality Q-factor of the nanoresonator.