Totally found 10042821 items.

  • [专利] 一种制备雷酚新内酯和异雷酚新内酯的方法
    本发明公开了一种制备雷酚新内酯和异雷酚新内酯的方法,包括:步骤1、取雷公藤干燥根粉碎,用95%乙醇回流提取,抽滤,滤液减压浓缩至无醇味,等体积石油醚脱脂,收集水溶液;步骤2、以NKA‑9大孔树脂为吸附树脂,采用湿法将预处理的树脂装入吸附柱中,将上述水溶液上样于NKA‑9大孔树脂,先用15%乙醇洗脱10个柱体积,再用68%乙醇洗脱,收集第13个柱体积的68%乙醇洗脱液,浓缩、冷冻干燥得混合粗品;步骤3、混合粗品的HSCCC分离纯化,两相溶剂系统为体积比为8:7:7:6的正己烷‑乙酸乙酯‑乙醇‑水。本发明方法制备的雷酚新内酯、异雷酚新内酯的纯度分别高达98.2%、98.7%;该方法对雷公藤干燥根中雷酚新内酯、异雷酚新内酯的制备回收率分别高达76.5%、93.6%。
  • [资讯] 08月17日中沙石化丙酮为5500元
    08月17日中沙(天津)石化有限公司关于丙酮的报价为5500元/吨。丙酮的出产地为天津;丙酮的属性:产品等级:优等品;含量:99.8%。该报价有效期为1天。
  • [期刊] Siting assessment of a water-electricity cogeneration nuclear power plant in Egypt
    Fresh water sources in Egypt are less than 13% of the world average per capita. To meet growing wtaer and electricity demands, projections were made up to the year 2025 cnsidering population growth, rise in standard of living, and development plans. A medium-sized nuclear desalination reactor was found to be a viable choice. This study was made to determine a suitable site for a plant in the water-sarce coastal governates of Matrouh, Red Sea, North Sinai, and South Sinai. Considering the effect of extreme climatic and geomorphological conditions on the plant and the effect of the plant on the area, it was found that the coastal strips from El-Arish to Rafah and from El-Dabaa to Saloum are the most suitable areas for construction of a nuclear power plant.
  • [期刊] 简析白龙江拟建引水工程对供水区水资源的影响
    利用白龙江干流白云和舟曲水文站实测径流资料,拟算出代古寺断面径流过程用以分析供水区不同保证率下水资源总量、天然河道径流量、水环境等指标的变化情况,从而定量的分析引水工程对供水区水资源配置的影响.研究表明:白龙江引水工程实施后对供水区水资源量影响有限,水功能区纳污能力略有降低,对水环境总体影响不大.
  • [期刊] Network analysis of the Chinese stock market during the turbulence of 2015-2016 using log-returns, volumes and mutual information
    We use mutual information and symbolization method of time series to construct minimum spanning tree of the financial network of log-returns and trading volumes of the top 110 companies on the Chinese stock market listed on the CSI 300 index from January 2014 to December 2017 to analyze the Chinese stock market's turbulence during 2015 to 2016. We construct three minimum spanning trees of pre-turbulence, turbulence and post-turbulence. The findings show that minimum spanning tree of turbulence has the significant differences in topological characteristics and network's measures with pre-turbulence and post-turbulence networks. Furthermore, the pre-turbulence network is robust against nodes attack while turbulence network is fragile against it. (C) 2019 Elsevier B.V. All rights reserved.
  • [期刊] The complete genome sequence of a second alphabaculovirus from the true armyworm, Mythimna unipuncta: implications for baculovirus phylogeny and host specificity
    The Mythimna unipuncta nucleopolyhedrovirus isolate KY310 (MyunNPV-KY310) is an alphabaculovirus isolated from a true armyworm (Mythimna unipuncta) population in Kentucky, USA. Occlusion bodies of this virus were examined by electron microscopy and the genome sequence was determined by 454 pyrosequencing. MyunNPV-KY310 occlusion bodies consisted of irregular polyhedra measuring 0.8-1.8 mu m in diameter and containing multiple virions, with one to six nucleocapsids per virion. The genome sequence was determined to be 156,647bp with a nucleotide distribution of 43.9% G+C. 152 ORFs and six homologous repeat (hr) regions were annotated for the sequence, including the 38 core genes of family Baculoviridae and an additional group of 26 conserved alphabaculovirus genes. BLAST queries and phylogenetic inference confirmed that MyunNPV-KY310 is most closely related to the alphabaculovirus Leucania separata nucleopolyhedrovirus isolate AH1, which infects Mythimna separata. In contrast, MyunNPV-KY310 did not exhibit a close relationship with Mythimna unipuncta nucleopolyhedrovirus isolate #7, an alphabaculovirus from the same host species. MyunNPV-KY310 lacks the gp64 envelope glycoprotein, which is a characteristic of group II alphabaculoviruses. However, this virus and five other alphabaculoviruses lacking gp64 are placed outside the group I and group II clades in core gene phylogenies, further demonstrating that viruses of genus Alphabaculovirus do not occur in two monophyletic clades. Potential instances of MyunNPV-KY310 ORFs arising by horizontal transfer were detected. Although there are now genome sequences of four different baculoviruses from M. unipuncta, comparison of their genome sequences provides little insight into the genetic basis for their host specificity.
  • [期刊] Newer Technologies in Breast Cancer Imaging: Dedicated Cone-Beam Breast Computed Tomography
    Dedicated breast computed tomography (CD is the latest in a long history of breast imaging techniques dating back to the 1960s. Breast imaging is performed both for cancer screening as well as for diagnostic evaluation of symptomatic patients. Dedicated breast CT received US Food and Drug Administration approval for diagnostic use in 2015 and is slowly gaining recognition for its value in diagnostic 3-dimensional imaging of the breast, and also for injected contrast-enhanced imaging applications. Conventional mammography has known limitations in sensitivity and specificity, especially in dense breasts. Breast tomosynthesis was US Food and Drug Administration approved in 2011 and is now widely used. Dedicated breast CT is the next technological advance, combining real 3-dimensional imaging with the ease of contrast administration. The lack of painful compression and manipulation of the breasts also makes dedicated breast CT much more acceptable for the patients. (C) 2018 Elsevier Inc. All rights reserved.
  • [期刊] China’s imports fall to 16-month low
    China’s thermal coal imports in November fell to their lowest level since July 2017, suggesting that the government’s stricter enforcement of import curbs is having an effect. Thermal coal imports — which include imported shipments of lignite, bituminous, and sub-bituminous coal — totalled 13.52mn t in November, down by 15pc from 15.97mn t in November 2017, according to China’s customs administration data. The imports also fell by 18pc compared with the previous month of October when thermal coal imports totalled 16.45mn t.
  • [学位] 韩国文化对延边朝鲜族的影响
    延边地区文化因为诸多的历史因素,她的传统文化可谓多姿多彩便丰富多样朝鲜族在近代和现代迁入到中国边疆延边,延边朝鲜族150多年的传承与发展,她的文化逐步形成了及区别与朝鲜半岛文化及其他世界各地的朝鲜族文化,又区别于汉族和其他民族的文化。延边朝鲜族的文化具有浓郁的民族性、时代性、传统性的特征。 2012年是中韩建交二十周年的日子。在建交二十周年期间,两国在各个领域的交流都出现了划时代的变化。建交以后的中韩关系,其发展势头非常迅猛,范围之广泛,程度之深入,在国际关系中实属罕见。一直以来,民族文化都是我国民族学、人类学和社会学的热门话题。在我国,由于受到历史变迁和社会发展的影响,少数民族大都不可避免地面临着文化的融合与同化。尤其少数民族往往扮演着弱势群体的角色,所以,少数民族的文化也自然的成为了主流文化背景下的一种弱势文化。 延边朝鲜民族是中国五十六个民族之一,延边朝鲜族文化也是中国文化中的一部分。而我国的朝鲜民族由于本身特殊的历史经历和现实的冲击中比较好的保存着自己固有的语言、风俗习惯、文化等。在经过无数次的考验后朝鲜民族依然保持着较高的文化水平和传统文化传承到至今。但随着改革开放的深入,市场经济的大潮和多元文化的影响之下,朝鲜族的传统文化体系逐渐被打破,而新的文化体系尚未形成之际,很多朝鲜族,特别是在新千年的年青一代在新的文化环境中感到困惑和迷茫。朝鲜由于近几年来经济发展比较滞后,政治的不安等因素,导致了我国的朝鲜民族和北朝之间的文化交流逐渐减少,而恰恰相反,韩国自从上世纪八十年代开始经济腾飞后,中国朝鲜族和韩国慢慢从经济上、文化上交流更多。特别是在中韩建交之后,延边朝鲜族用自己的亲戚、人缘关系、语言文化等优势,活跃的与韩国进行各种经济与文化交流。同时,在全球化的背景之下,也有不少韩国迁移者入住在延边州开始生活。这些因素更加有力的给了延边朝鲜族与韩国交流文化的时代机遇。 本论文采用的主要方法是实地调查方法和各种文献资料分析相结合的方法,根据韩国文化对延边朝鲜族的影响和变化为出发点,阐明韩国文化对延边朝鲜族文化在发展过程中的影响,以及延边朝鲜族本身在文化发展中出现的一些问题,并立足于延边朝鲜族的文化的实际,提出了可行的发展对策和建议。
    关键词: 延边朝鲜族;韩国文化;人缘关系;风俗习惯
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