共查询到20条相似文献，搜索用时 46 毫秒
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分子折叠体是一类由非共价键稳定的、采用有序构象的寡聚物或聚合物. 我们设计并合成了三类非天然的折叠体，包括：1）由疏溶剂作用驱动的并入萘环板块的寡聚乙二醇折叠体，2）由分子内氢键驱动的寡聚酰肼折叠体，3）由分子内氢键驱动的并入锌卟啉板块的寡聚苯酰胺折叠体. 定性和定量的研究揭示，在有机溶剂中这些折叠体可以作为非天然受体分子高效络合或识别结构匹配的有机分子和离子，并且氢键驱动的折叠体可以通过络合作用实现超分子体系的手性诱导或手性放大. 相似文献
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对多年来垦东海区的调查资料分析表明,沉积体不稳定性比较突出,对海洋工程设施危害很大,主要表现在以下几个方面:(1)软弱层是沉积体不稳定的根本因素.(2)水下斜坡是垦东海区所在黄河三角洲上主要的工程不稳定区;(3)海底冲刷和海洋动力调整在海底形成的活动层对海底铺设的管线和构筑物造成危害,应引起高度重视. 相似文献
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目的:开发适合液质联用的聚合物检测方法,考察托西酸舒他西林的聚合物杂质.方法:采用ZORBAX Eclipse Plus C18色谱柱(4.6 mm×100 mm,3.5 μm),以甲酸盐缓冲液(0.01 mol/L甲酸铵溶液,甲酸调节pH至3.0)为流动相A,乙腈为流动相B,梯度洗脱,流速1mL/min;检测波长215 nm,柱温25℃,并联用质谱测试未知聚合物杂质峰的分子量.结果:在原料药杂质谱中识别出两个新聚合物杂质,分子量分别为721.2 m/z、926.3 m/z.结论:考察结果可为药品的质量控制提供参考. 相似文献
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为建立四方藤的指纹图谱,文章用高效液相色谱(HPLC)联合飞行时间质谱(TOF-MS)结合离子阱多级质谱(Ion-trap/MSn)分析研究不同产地四方藤中的化学物质。高效液相色谱配备DAD检测器及C_(18)色谱柱(250mm×4.6mm,5μm),在流动相为0.1%甲酸水-甲醇体系,流速为0.8mL/min,检测波长为254nm的条件下梯度洗脱。结果表明,不同产地的四方藤HPLC指纹图谱中有5个共有物质峰,该分析方法建立的指纹图谱可为四方藤质量标准的建立及质量评价提供实验依据。 相似文献
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生物标志化合物(或称分子化石)系指地质体中产出的特征有机化合物。由于它们具有生物体化合物的基本分子骨架,而能提供生物输入、沉积环境与成岩变化等多方面的信息,已在国内外石油勘探中发挥出重要作用。如进行原油对比、油源对比,有机质成熟度的判别、确定母质类型与生物输入源、生物降解油与重油研究,以及探讨石油的原生运移等,从而成为当代有机地球化学的重要生长点之一。 相似文献
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分析复杂地质体三维模型的构建方法,本地质体通过使用vbnet+Direct3D来建模实现.在Directx3D中,使用三种基本图元信息(点,线,和三角形面)来构建复杂的三维地质体模型.本三维地质体生成时,根据采集的离散数据,通过克里金插值算法生成地层表面,然后通过广义三棱柱法,将生成的地层表面通过三棱柱连接生成地质体模型. 相似文献
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对ZnO单晶材料不同温度下进行了光致发光研究。室温下ZnO单晶有两个发光峰,分别为375nm的紫外发光峰和570nm的可见光发光带。随着温度的降低,出现两个紫外发光峰,分别为自由激子(FX)和束缚激子(D0X)发光峰,并且束缚激子发光峰随着温度降低较自由激子变化明显。较低温度时在370nm到400nm出现多个发光峰,为声子(LO)参与的受主束缚激子(A0X)发光峰。10K时出现四个紫外发光峰,分别为自由激子(FX)、表面激子(SX)和束缚激子(D0X)发光峰。 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献
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《中国科学院院刊(英文版)》2014,(3):212-213
<正>In February 2014,the 30th Chinese Antarctic inland expedition team reported that they have successfully conducted the seeing measurement at the Antarctic Taishan Station using a Differential Image Motion Monitor(DIMM)developed by the Nanjing Institute of Astronomical Optic and Technology(NIAOT),Chinese Academy of Sciences.In astronomy,seeing is a physical parameter that describes the irregular movement and blur of the star 相似文献
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XIN Ling 《中国科学院院刊(英文版)》2014,(4):270-271
Amassive overhaul is coming to the Chinese Academy of Sciences （CAS）. To straighten its ＂fragmented, inefficient research＂, the academy has decided to restructure its 104 institutes for better teamwork. 相似文献
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SONG Jianlan 《中国科学院院刊(英文版)》2014,(4)
<正>DNA demethylation in mammalian zygotes,a biochemical process through which the parental genomes let go the epigenetic marks from their"past lives"to obtain totipotency,has long fascinated biologists:how does it happen?A joint team at the CAS Shanghai Institutes for Biological Sciences tells a surprising story. 相似文献
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China is one of the fastest growing economies worldwide. Are science and research also in the fast lane? We talked with LUO Yuan, scientist at the Institute of Coal Chemistry in Shanxi, and Axel Mosig, Professor at Ruhr University in Bochum, who has first-hand experience working and living in China. 相似文献
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INS 《中国科学院院刊(英文版)》2014,(4):311-311
Neonatal heart:Largely,postnatal coronary vessels might not have expanded from preexisting embryonic vasculature as formerly believed–see what CAS biologists revealed in page 311. 相似文献
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《中国科学院院刊(英文版)》2014,(4):312-312
<正>Recently a group of researchers at the unit of molecular virology,Institut Pasteur of Shanghai,Chinese Academy of Sciences revealed a new mechanism to regulate the survival of influenza A virus and reported their discoveries in the Journal of Virology on July 相似文献
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《中国科学院院刊(英文版)》2014,(4):319-320
<正>Amber-bearing deposits are among the most important Konservat-Lagersttten providing unique windows into past ecosystems.Fushun amber has been known for over a century and was traditionally regarded as an important source of medicine as well as organic gemstones.The inclusions,however,were not the subject of any comprehensive investigation 相似文献