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噻唑类杀虫剂的研究进展 总被引:2,自引:0,他引:2
目前杂环化合物的发展呈现出多元化的趋势,其中噻唑类化合物是近年来发展的一个新亮点。尤其噻唑基团引入到各种不同的化合物结构中,通过结构修饰能产生一系列具有广谱生物活性化合物,使得它在新型超高效农药创制中发挥出越来越重要的作用。本文从杀虫方面对噻唑化合物的生物活性研究进行了综述,重点介绍了该类化合物的一些生物活性研究方面的工作,简述了不同取代基团对噻唑类衍生物生物活性的影响,并对它的发展趋势和应用前景作了展望。 相似文献
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笔者等对含硫杂环化合物的合成及其生物活性进行了研究。其间,亦对由有机硫化合物(例如二硫化碳和异硫氰酸酯)衍生的中间体的反应性进行了广泛的研究。为了创制新的生物活性化合物,其有效的方法之一,是对已知生物活性化合物进行化学结构的改进。防治水稻稻瘟病的内吸杀菌剂富士一号(2)对某些植物和害虫都呈现生长调节活性。鉴于富士一号化学结构的新颖性和生物活性的多样性,引起了笔者等人的注意,以它作为新的农药化学结构的先导化合物。 相似文献
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酰基硫脲类化合物的生物活性研究进展 总被引:3,自引:1,他引:2
酰基硫脲类化合物具有广泛的生物活性,可作为除草剂、杀菌剂及植物生长调节剂等。本文简要综述了近年来该类化合物生物活性的研究近况。 相似文献
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香豆素是一类重要杂环化合物,具多种生物活性,在医药、食品等领域有重要用途。本文综述了近年来香豆素生物活性研究进展,并简单介绍了含有苯并吡喃酮化合物的合成方法,为香豆素类化合物生物活性的深入研究提供依据。 相似文献
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采用DUO-ICP-AES同时测定精对苯二甲酸中钴、铬、铁、锰、钼、镍、钛,并对仪器的分析线选择、背景校正、入射功率、雾化器压力、辅助气流量、冷却气流量、蠕动泵转速的影响及共存元素的干扰、硝酸铯灰化助剂等因素进行了详细的研究。方法的检测限:钴0.0097 mg/L;铬0.0021 mg/L;铁0.0078 mg/L;锰0.0012 mg/L;钼0.0027 mg/L;镍0.016 mg/L;钛0.0027 mg/L,回收率和精密度分别为93.0%~99.5%和0.37%~3.2%。该方法快速简便,具有良好的精密度和准确度,适用于进出口精对苯二甲酸的日常检验。 相似文献
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The development of new methods for preparing polyfunctional organometallics has made a broad range of such reagents available for various transition metal-catalyzed cross-couplings. An overview of the most general preparation methods will be presented. Applications to practical cross-coupling procedures will be covered, emphasizing the functional group compatibility and the reaction scope. 相似文献
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Mailadil T. Sebastian Sam Solomon Ravindran Ratheesh Jacob George Pezholil Mohanan 《Journal of the American Ceramic Society》2001,84(7):1487-1489
Microwave ceramic dielectric resonators (DRs) based on RETiNbO6 (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, and Yb) have been prepared using the conventional solid-state ceramic route. The DR samples are characterized using XRD and SEM methods. The microwave dielectric properties are measured using resonant methods and a net work analyzer. The ceramics based on Ce, Pr, Nd, and Sm have dielectric constants in the range 32–54 and positive coefficient of thermal variation of resonant frequency (τf ). The ceramics based on Gd, Tb, Dy, Y, and Yb have dielectric constants in the range 19–22 and negative τf . 相似文献
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Clive A. Randall Zhongming Fan Ian Reaney Long-Qing Chen Susan Trolier-McKinstry 《Journal of the American Ceramic Society》2021,104(8):3775-3810
Antiferroelectric (AFE) materials are of great interest owing to their scientific richness and their utility in high-energy density capacitors. Here, the history of AFEs is reviewed, and the characteristics of antiferroelectricity and the phase transition of an AFE material are described. AFEs are energetically close to ferroelectric (FE) phases, and thus both the electric field strength and applied stress (pressure) influence the nature of the transition. With the comparable energetics between the AFE and FE phases, there can be a competition and frustration of these phases, and either incommensurate and/or a glassy (relaxor) structures may be observed. The phase transition in AFEs can also be influenced by the crystal/grain size, particularly at nanometric dimensions, and may be tuned through the formation of solid solutions. There have been extensive studies on the perovskite family of AFE materials, but many other crystal structures host AFE behavior, such as CuBiP2Se6. AFE applications include DC-link capacitors for power electronics, defibrillator capacitors, pulse power devices, and electromechanical actuators. The paper concludes with a perspective on the future needs and opportunities with respect to discovery, science, and applications of AFE. 相似文献
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ICP-OES测定大量元素水溶肥料中锌、镁、铜、铁、锰、钼、硼含量 总被引:1,自引:0,他引:1
采用ICP-OES对大量元素水溶肥料中微量元素锌、镁、铜、铁、锰、钼、硼进行分析,研究确定了最佳分析条件。加标回收率为96.94%~106.2%,RSD为0.50%~1.40%,检出限为0.001 8~0.218 0 mg/L,方法简便、快速、准确。 相似文献
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《国际聚合物材料杂志》2012,61(6):497-509
Glass fiber reinforced composites based on thermosets are the traditional materials used for many applications due to their good mechanical properties. The non-recyclability of these materials has led to the necessity to develop thermoplastic composites and industrial processes for their manufacture [1]. The present paper deals with the preparation of thermoplastic pre-pregs unidirectionally reinforced with Twarn® and their mechanical characterization. 相似文献
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对水镁石、水菱镁石和斜方云石资源及其加工和应用进行了评述。包括上述资源的发展历史、化学组成和物性参数、资源储量和矿石品位、生产加工以及在不同领域(如镁质阻燃剂、中和剂、重金属离子脱除剂、镁肥、饲料添加剂等)的应用,并对它们的发展前景进行了展望。 相似文献
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《Ceramics International》2020,46(4):4280-4288
Rare earths RE's (Pr, Y, Gd, Ho, Yb) substituted MnZn spinel ferrites with composition of Mn0.5Zn0.5M0.02Fe1.98O4 (M = Pr, Y, Gd, Ho, Yb) are prepared by sol gel combustion approach. Low sintering temperature (500 °C) is used to sinter the RE's doped MnZn samples. MnZn samples are further characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) to measure the cubic crystalline structure, particle size, morphology, porosity and grain size. Cubic crystalline phase of prepared RE's doped MnZn ferrites is confirmed by x-ray diffraction (XRD). The morphology, porosity and grain size are observed using FESEM. The magnetic properties of RE's doped MnZn nanoferrites are analyzed by vibrating sample magnetometer (VSM). Coercivity (Hc), remanence (Mr) and saturation magnetization (Ms) are calculated from the magnetic loops. The saturation and remanence of the nanoferrites are increased by the substitution of RE's metal ions and varies from 14.76 to 26.36 emu/g and 9.98–22.48 emu/g respectively. Bohr magneton and anisotropy constant are calculated from the recorded magnetic data. The conductive analysis of the prepared samples is studied at 40 °C −300 °C temperature, leading to the conductivity measurements from 1.12 × 10-2 Ω-1-cm-1 to 9.52 × 10-2 Ω-1-cm-1. UV–Vis spectroscopy is used to determine the semi conducting nature of RE's doped MnZn spinel ferrite samples. The magnetic, conductive and optical study of the RE's doped MnZn nanoferrites sintered at low temperature suggests the use of these materials for microwave absorption, supercapacitor, lithium ion batteries and nanoelectronics industrial applications. 相似文献
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In principle, the oil milling process is straightforward. The wide variety of equipment in use reflects, however, a multiparametric
process. The main limiting parameters are kind of seed, oil content, particle strength, particle structure, temperature, moisture,
particle size, residence time, mechanical forces, etc. Additionally, the seed specific parameters vary not only between kinds
of seed but also for the same seed, due to different conditions in climate, soil, and harvesting. Therefore, equipment design
must be widely based on statistical averages of the limiting parameters. In other words, exact precalculation of the single
technological steps is impossible. As a consequence, for more than 5,000 years, the oil milling process has been in the stage
of being optimized. The acutal technical standard is very satisfying, but there is still a strong need for further research
and development. Currently, as in the past, the oil milling process seems to be not so much a science as an art. 相似文献