共查询到20条相似文献,搜索用时 78 毫秒
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用多种核磁共振实验方法并结合其它结构信息,确定1,2,4,6-四苯基-2-羟基8-氮杂双环[3、2、1]辛烷的化学结构,并指定该化合物的核磁共振归属. 相似文献
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二维INADEQUATE谱在NMR研究中具有重要价值,本文以二维INADEQUATE谱为主,结合DEPT,同核及异核位移相关谱,指认了δ-维生素E的碳谱谱峰,并由碳氢相关谱给出了各氢的化学位移,本文对δ-维生素E碳谱某些峰和二维INADEQUATE谱做了讨论,并对文献数据做了讨论,并对文献数据做了修正. 相似文献
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本文报告了用多种核磁共振实验方法并结合其它结构信息,研究并首次确定了内蒙产的乌拉尔甘草(Glycyrrhiza uralensis Fisch)中一种新甘草三萜内酯的化学结构并命名为甘乌内酯(Glyuranolide)。 相似文献
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该文用NMR方法研究暗霉素T的化学结构.从1D谱和几种2D技术确认了暗霉素T是氨基糖苷类化合物.讨论了化合物的构型,并通过改变溶剂推断了氨基的连接位置. 相似文献
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在数学相关分析的基础上,建立了获得连续波电子自旋共振(continuous-wave electronspin resonance, CW-ESR)的二维相关谱的方法. 对光照产生的2-甲基-2-亚硝基-丙烷(2-methyl-2-nitrosopropane, MNP)的自捕捉自由基的一系列CW-ESR谱进行相关分析处理,首次得到了同步和异步的二维电子自旋共振(2D ESR)相关谱. 这种利用数学相关分析方法所得到的2D ESR相关谱将为扩大CW ESR的应用领域及获取更多的有用信息开拓新的途径. 相似文献
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本文用COSY,CHCOR等二维核磁共振技术对TRANILAST,2[]3-(3.4-二甲基苯基)1-氧代-2-丙烯基]氨基]苯甲到进行了~1H、~(13)C NMR谱数据分析及归属,并结合~(13)C弛豫时间T_1 及变温实验对合成产品进行了结构鉴定. 相似文献
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本文叙述测定半导体扩散层表面浓度、P-n结深度及扩散系数的霍耳效应法。导出了求算半导体扩散层表面浓度、P-n结深度及扩散系数的一组积分公式。对砷由气相扩散入锗这一情况进行了详细研究:对上述公式进行数值积分并给出一系列图线,利用这些图线从实验值求得表面浓度等上述参数。实验表明:此法所测得的结深度和表面浓度分别与光干涉法直接测得的结深度和平均电导法测得的表面浓度,在误差范围内很好符合;而且此法所测得的扩散系数与B?senberg用电容法测得的也极为接近。扩散系数与温度的关系为D=2.3exp(-2.36/(kT)),当N0=1014厘米-3;D=1.7exp(-2.36/(kT)),当N0=1016厘米-3。 相似文献
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Olivier Mathieu 《Communications in Mathematical Physics》1996,176(2):467-474
Letn be an integer. Denote byA
n one of the following two graded vector spaces: (a) the space of all multilinear Poisson polynomials of degreen (with a grading described below), or (b) the cohomology of the space of alln-uples of complex numbersz
1,..., zn withz
izj forij. We prove that the natural action of
n
on each homogeneous component ofA
n can be extented to an hidden
n+1
-action and we compute the corresponding character (the
n
-character being already given by Klyaschko and Lehrer-Solomon formulas). 相似文献
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介绍了8~9GHz极低噪声低温放大器的研制。在≤15K的工作温度下,实测放大器的主要性能指标如下:等效噪声温度≤7.9K;增益>31dB,带内起伏≤1dB;输入反射损耗<-21dB;输出反射损耗<-23dB。它的研制成功,实现了深空探测、天文观测等X波段宽带低温接收机的核心器件国产化。 相似文献
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本文测定了新合成的,具有生理活性的1-(4-吡啶甲酰)-4 -苯基氨基硫脲,1-(4-吡啶甲酰)-4-对氯苯基氨基硫脲,1-(4 -吡啶甲酰)-4-对溴苯基氨基硫脲3-(4-吡啶基)-4-苯基-1,2,4,-三唑啉-5-硫酮,3-(4-吡啶基)-4-对氯苯基-1,2,4,-三唑啉-5-硫酮,3-(4-吡啶基)-4-对溴苯基-1,2,4-三唑啉-5-硫酮六个新化合物的~(13)C-NMR谱,并通过~(13)C-NMR谱中的宽带去偶,偏共振及APT技术,模型化合物对照,讯号强度对比及芳基取代基常数计算等方法,进行了上述化合物~(13)C-NMR谱峰的归属,并得到了甲酰肼基在吡啶环4位取代后对吡啶环各碳所产生的取代基效应. 相似文献
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We apply the pseudoextension mechanism, which in the undeformed case gives the centrally extended Galilei group {ie137-02} as a contraction of a trivial extensionP×U(1) of the Poincaré group, to the case of the-Poincaré algebra. As a result, the four-dimensional {ie137-03}-deformed extended Galilei algebra is obtained.Presented at the 4th Colloquium Quantum Groups and Integrable Systems, Prague, 22–24 June 1995. 相似文献
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Jun Akimitsu Jiro Amano Masaki Yoshinari Michio Kokubun Tatsuya Iwasaki Satoshi Okuma Nobuhiko Nishida Kusuo Nishiyama Nobuo Mori 《Hyperfine Interactions》1994,85(1):187-192
We report SR measurements of Pr2CuO4– and (Pr2–xCex)CuO4– single crystals in the temperature range 4.2K300K. Two spin reorientation phase transitions were observed, although neutron scattering experiment could not detect these phase transitions. These allow us to conclude that magnetic moments of the Cu atoms order in an antiferromagnetic noncollinear cross like structure including a hidden canting spin arrangement. 相似文献
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We study instanton effects on inclusive semileptonicb→u decay using the heavy quark effective field theory and the operator product expansion. The effect contributes not only to the hadronic matrix element but also to the coefficient functions in the operator product expansion. We find that the coefficient function is singular near the boundaries of the phase space. In order to use perturbative QCD reliably, it is necessary to introduce smearing near the boundary. However the instanton contribution tob→c decay seems negligibly small. 相似文献
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Superconductivity in the Bi - Sr - Cu - O system 总被引:4,自引:0,他引:4
C. Michel M. Hervieu M. M. Borel A. Grandin F. Deslandes J. Provost B. Raveau 《Zeitschrift für Physik B Condensed Matter》1987,68(4):421-423
During the investigation of the system Bi–Sr–Cu–O a novel family of superconducting oxides, close to the composition Sr2Bi2Cu2O7+ has been isolated, with a midpoint critical temperature ranging from 7 K to 22 K. The X-ray diffraction and high-resolution electron microscopy studies have shown its relationships with perovskite and demonstrated its bidimensional character. The possible relationships of this lamellar oxide with Aurivillius phases is discussed. 相似文献