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排序方式: 共有188条查询结果,搜索用时 15 毫秒
1.
K. G. Korolev O. I. Lomovskii O. A. Rozhanskaya V. G. Vasil'ev 《Chemistry of Natural Compounds》2003,39(4):366-372
A waste-free technology for mechanochemical processing of fir needles into a biologically active preparation that regulates plant growth was developed. A preparation exhibiting cytokinin activity due to the presence in it of water-soluble forms of triterpene acids can be prepared using the proposed method. The effectiveness of the proposed method was confirmed by instrumental methods and biological tests. 相似文献
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Catalina Rosales-Lpez Felipe Arce-Torres Mariana Monge-Artavia Miguel Rojas-Chaves 《Molecules (Basel, Switzerland)》2022,27(13)
The use of substances or conditions as elicitors can significantly increase the production of secondary metabolites. In this research, the effects of different elicitors on the production of antioxidant secondary metabolites were evaluated in a strain of Ganoderma sp. The elicitors tested were pH changes in different growth phases of the fungus (pH 3, 5.5 and 8), different concentrations of peptone as a nitrogen source (1 g/L and 10 g/L), and the addition of chemical agents to the culture medium (ethanol, growth regulators, and salts). The alkaline pH during the stationary phase and the high availability of nitrogen were effective elicitors, producing cultures with higher antioxidant activity (37.87 g/L and 43.13 g/L dry biomass) although there were no significant differences with other treatments. 相似文献
4.
A novel anti-jamming integrated CMOS current-sensing circuit for current-mode buck regulators is presented. Based on the widely-used traditional current-sensing structure, anti-jamming performance is improved significantly by adding on-chip capacitors and one-shot circuit. Also the transient response is faster through the introduction of current offset. The circuit is concise, simple to implement and suits for SoC applications with single power supply. A dualoutput current-mode DC-DC buck converter with proposed structure has been fabricated with a 0.5 μm CMOS process for validation. In the 2.5–5.5 V input range, the two channels work steadily in the load current range of 0–600 mA. And the measured maximum efficiency is up to 96%. 相似文献
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随着5G、人工智能及物联网等技术的蓬勃发展和半导体工艺尺寸的不断缩小,终端设备处理器和服务器的数据处理能力及其他性能快速提升,这对电源管理芯片提出了新的需求。而多相并联结构变换器在低压大电流应用、快速瞬态响应等方面具有极大的优势,被公认为处理器电源的最佳解决方案之一。文章从多相Buck变换器的原理及优势出发,研究和探讨了多相Buck变换器设计中的多相电流均衡方法、控制模式及效率提升等关键技术的发展和最新的研究进展,进而明确多相Buck变换器的关键发展趋势和面临的挑战。 相似文献
6.
H.-D. Knöfel 《Isotopes in environmental and health studies》2013,49(8):316-320
In vorliegender Arbeit wird eine kurze Darstellung der Grundlagen, Erfordernisse, Vor- und Nachteile des Radioimmunoassay für Pflanzenhormone gegeben. The purpose of this paper is to discuss briefly the basis, requirements, advantages, and disadvantages of radioimmunoassay with respect to plant hormones. 相似文献
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液相色谱-四极杆飞行时间质谱法快速测定草莓中6种植物生长调节剂的残留量 总被引:6,自引:0,他引:6
建立了高效液相色谱-四极杆飞行时间串联质谱(HPLC-Q TOF MS)快速检测草莓中2,4-滴、对氯苯氧乙酸、3-吲哚丁酸、氯吡脲、脱落酸、玉米素6种植物生长调节剂的分析方法。样品采用QuEChERS方法(Quick, Easy, Cheap, Effective, Rugged and Safe method)进行前处理(乙腈提取,C18吸附剂净化),采用Eclipse XDB-C8色谱柱(150 mm×4.6 mm, 5 μm),以乙腈-5 mmol/L乙酸铵-0.1%(v/v)甲酸水溶液为流动相,梯度洗脱,Q TOF MS电喷雾负离子模式分析检测。在全扫描采集模式下,以准分子离子峰的峰面积定量,以化合物的精确质量数定性。在Target MS/MS采集模式下,通过碎片离子的精确质量数进一步确证化合物。各化合物在0.005~1.0 mg/L范围内均呈现良好的线性关系,相关系数均大于0.99。6种化合物的检出限为1~5 μg/kg,添加回收率为87%~107%,相对标准偏差(RSD)均小于10%(n=6)。本方法简便快捷,选择性好,灵敏度高,可满足国内外现行法规的限量要求。 相似文献
8.
Xiao-Qing Wu Juan Huang Mei-Zi Wang Zhe Zhang Xin-Lu Li Xin-Ling Yang Stephen S. Tobe 《中国化学快报》2016,27(4):559-562
Insect growth regulators play an important role in integrated pest management strategies.The FGLa–allatostatins(ASTs)are a family of neuropeptides that can inhibit juvenile hormone(JH)biosynthesis by the corpora allata(CA)of Diploptera punctata in vitro,are regarded as insect growth regulator candidates.In the search for new potential mimics and to explore the effect of linker length on inhibiting JH biosynthesis,a series of AST analogs were synthesized by modifying the linker of K24,which was found to have a significant effect on JH biosynthesis in vitro in our previous study.Functional evaluation demonstrated that all the target compounds can activate the Dippu-Ast R,albeit with different potencies.Analog L6 with the longest linker(n=5),exhibited not only a promising effect on inhibition of JH biosynthesis both in vitro and in vivo,but also good activity in inhibiting basal oocyte growth.Structure–activity relationships(SAR)studies showed that longer linkers provided greater contribution to activity. 相似文献
9.
对卫星电源系统控制结构进行介绍,比较了传统电源功率控制结构和改进结构的特点,并简要说明其控制方法,研究卫星电源系统中直流母线与负载间的降压变换器参数和控制策略设计过程,给出参数计算方法,通过Matlab软件仿真验证了所采用方法的正确性。 相似文献
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