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31.
32.
杜仲胶研究进展及发展前景 总被引:32,自引:0,他引:32
本文介绍了杜仲胶发展简史及其塞础研究和应用开发取得的新进展。指出:高弹性杜仲胶的诞生,杜仲胶硫化过程三阶段及与之对应的三类不同材料的发现,杜仲胶材料工程学的形成及“橡一塑统一材料谱”概念的提出,把杜仲胶的研究及开发带到了一个新阶段,进而推动了系列功能材料的开发。最后讨论了以杜仲胶为中心的杜仲资源综合利月的前景。 相似文献
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Ylenia Pieracci Roberta Ascrizzi Valentina Terreni Luisa Pistelli Guido Flamini Laura Bassolino Flavia Fulvio Massimo Montanari Roberta Paris 《Molecules (Basel, Switzerland)》2021,26(13)
Cannabis sativa L. is an annual species cultivated since antiquity for different purposes. While, in the past, hemp inflorescences were considered crop residues, at present, they are regarded as valuable raw materials with different applications, among which extraction of the essential oil (EO) has gained increasing interest in many fields. The aim of the present study is the evaluation of the yield and the chemical composition of the EO obtained by hydrodistillation from eleven hemp genotypes, cultivated in the same location for two consecutive growing seasons. The composition of the EOs was analyzed by GC–MS, and then subjected to multivariate statistical analysis. Sesquiterpenes represented the main class of compounds in all the EOs, both in their hydrocarbon and oxygenated forms, with relative abundances ranging from 47.1 to 78.5%; the only exception was the Felina 32 sample collected in 2019, in which cannabinoids predominated. Cannabinoids were the second most abundant class of compounds, of which cannabidiol was the main one, with relative abundances between 11.8 and 51.5%. The statistical distribution of the samples, performed on the complete chemical composition of the EOs, evidenced a partition based on the year of cultivation, rather than on the genotype, with the exception of Uso-31. Regarding the extraction yield, a significant variation was evidenced among both the genotypes and the years of cultivation. 相似文献
35.
Andriy Panasyuk 《Annals of Global Analysis and Geometry》2008,33(1):1-10
For a quite general class of Lie algebras with a nontrivial ideal we derive a formula for the index generalizing the Raïs formula for the index of semidirect products. The method of proof of our formula is based on the so-called “symplectic reduction by stages” scheme. 相似文献
36.
A. F. Aleksandrov D. N. Vaulin A. P. Ershov V. A. Chernikov 《Moscow University Physics Bulletin》2009,64(1):100-102
Three stages of a pulse electric discharge were revealed. The discharge occurred in the atmosphere along a free water surface
between a tip placed at some distance from the water surface and a distant electrode immersed in the water.
Original Russian Text ? A.F. Aleksandrov, D.N. Vaulin, A.P. Ershov, V.A. Chernikov, 2009, published in Vestnik Moskovskogo
Universiteta. Fizika, 2009, No. 1, pp. 95–97. 相似文献
37.
具有急慢性阶段的SIS流行病模型的稳定性 总被引:5,自引:0,他引:5
本文系统研究了具有急性和慢性两个阶段的SIS流行病模型.由两节构成,第一节建立和研究了具有急性和慢性两个阶段的SIS流行病模型,该模型是由三个常微分方程构成的方程组;第二节在第一节的基础上建立和研究了具有慢性病病程的SIS流行病模型;该模型既含有常微分方程,又含有偏微分方程.假设所研究的国家或地区的总人口N(t)服从增长规律: N'(t)=A—μN(t),运用微分方程和积分方程中的理论和方法,得到了这两个模型再生数R0的表达式.证明了无病平衡态的全局渐近稳定性,给出了两模型地方病平衡态的存在性和稳定性条件. 相似文献
38.
Proteome maps obtained by synchronization of the wild-type Caenorhabditis elegans development reflected stage-dependent molecular differences and revealed dynamic cytoskeletal processes during ontogenesis. Distinct protein spots that may function as molecular markers for the corresponding developmental stages were mass spectrometrically identified. The amount of the Cu(2+)- Zn(2+) superoxide dismutase (CE23550) and an aspartyl proteinase (CE21681) was highest in the first larval stage (L1) and decreased during the ontogenesis from the first larval stage to the adult. Tropomyosin III (CE29059) was prominently present in the first and second larval stage (L1/L2). Abundances of actin 1 or 4 (CE12358 or CE13148) and tropomyosin I (CE28782) were particularly high in multiple spots in the third larval stage (L3). Interestingly, the amount of DIM-1 protein (CE27706), reflected by two spots, was the lowest in this stage. A particular splicing factor (CE31089) was detected only in the fourth larval stage (L4), whereas a spot with high abundance representing the cuticle collagen (CE02272) was only found highly expressed in adult animals (A). In addition, a Ca(2+)-binding protein (CE12368) and one protein spot which has not yet been identified, both reached their maximal spot intensities in the adult stage (A). Moreover, the ASP-1, CCT-5, GPD-1, GPD-2, HSP-6, HSP-16.2, IFB-2, LEC-2, LIN-53, LMN-1, MDH-1, NUD-1, RPA-0, RSP-12, SOD-1, TBB-1, TBB-2, TMY-1, UNC-60, and VIT-2 proteins for which mutants are available and two still unidentified protein spots which were present in all developmental stages, have been reproducibly localized in proteome maps of distinct ontogenesis states. 相似文献
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EAST����Դʧ������ϵͳ����Ƽ�ģ��ʵ�� 总被引:1,自引:0,他引:1
给出了EAST极向场磁体电源失超保护系统的设计方案,描述了两种失超保护开关——直流快速开关和爆炸开关采用的两级换流结构的设计和工作原理,分析了这种结构在换流过程中的规律,该结构有效地解决了开关开断直流大电流的难点。通过模拟实验证明了该失超保护系统满足设计要求。 相似文献