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411.
Rui Xu Jimei Lu Junxian Wu Daqing Yu Shanshan Chu Fengya Guan Weiwei Liu Jianpeng Hu Huasheng Peng Liangping Zha 《Journal of separation science》2022,45(5):1067-1079
Traditional Chinese medicine is made from the rhizome of Atractylodes lancea (Thunb.) DC. (Compositae), known as Cangzhu. In this study, gas chromatography-mass spectrometry was used to identify and quantify the volatile oils of different organs of A. lancea from four regions of China: Jiangsu, Anhui, Henan, and Hubei provinces. The volatile oils of A. lancea were qualitatively and quantitatively characterized using gas chromatography-mass spectrometry combined with laser microdissection. The results identified 21 components in A. lancea, the majority of the components were found in the rhizomes, followed by the fibrous roots, flowers, leaves, and stems. According to the contents of volatile oils in A. lancea, it was divided into Dabieshan (mainly includes hinesol and β-eudesmol) and Maoshan types (mainly includes atractylon and atractylodin), and the ratios of hinesol:β-eudesmol:atractylon:atractylodin were 17.06:4.55:0:1, 12.66:11.71:0.99:1, 7.43:6.23:0:1, and 0.13:0.16:1.52:1 in A. lancea from AH, HN, HB, and JS, respectively. Tissue-specific study indicated that Dabieshan type mainly includes elemol, hinesol, and β-eudesmol in the periderm and secretory cavities of A. lancea, whereas Maoshan type mainly includes atractylon, atractylodin, little hinesol, and β-eudesmol in the secretory cavities. Conversely, no volatile oils were detected in the cortex, phloem, xylem, vascular ray, or pith. This study provides a foundation for further evaluation and utilization of A. lancea. 相似文献
412.
Huashui Zhan 《Proceedings of the American Mathematical Society》2007,135(6):1923-1927
Let be a complete noncompact -manifold with collapsing volume and . The paper proves that is of finite topological type under some restrictions on volume growth.
413.
In this paper, we introduce and study a model of Lotka-volterra chemostat food chain chemostat with periodically varying dilution
rate, which contains with predator, prey, and substrate. We investigate the subsystem with substrate and prey and study the
stability of the periodic solutions, which are the boundary periodic solutions of the system. The stability analysis of the
boundary periodic solution yields an invasion threshold. By use of standard techniques of bifurcation theory, we prove that
above this threshold there are periodic oscillations in substrate, prey, and predator. Simple cycles may give way to chaos
in a cascade of period-doubling bifurcations. Furthermore, we numerically simulate a model with sinusoidal dilution rate,
by comparing bifurcation diagrams with different bifurcation parameters, we can see that the system experiences following
process: periodic solution → periodic doubling cascade → chaos. 相似文献
414.
In this paper, we introduce and study a model of a Monod–Haldene type food chain chemostat with seasonally variably pulsed
input and washout. We investigate the subsystem with substrate and prey and study the stability of the periodic solutions,
which are the boundary periodic solutions of the system. The stability analysis of the boundary periodic solution yields an
invasion threshold. By use of standard techniques of bifurcation theory, we prove that above this threshold there are periodic
oscillations in substrate, prey and predator. Simple cycles may give way to chaos in a cascade of period-doubling bifurcations.
Furthermore, bifurcation diagrams have shown that there exists complexity for the pulsed system including periodic doubling
cascade, periodic halving cascade and Pitchfork bifurcations and tangent bifurcations.
相似文献
415.
Let \(\overline{p}(n)\) denote the number of overpartitions of n. Recently, congruences modulo powers of 2 for \(\overline{p}(n)\) were widely studied. In this paper, we prove several new infinite families of congruences modulo powers of 2 for \(\overline{p}(n)\). For example, for \(\alpha \ge 1\) and \(n\ge 0\),
相似文献
$$\begin{aligned} \overline{p}(8\cdot 3^{4\alpha +4}n+5\cdot 3^{4\alpha +3})\equiv 0 \quad (\mathrm{mod}\,\,{2^8}). \end{aligned}$$
416.
Let \(b_{13}(n)\) denote the number of partitions of n such that no parts are divisible by 13. In this paper, we shall prove several infinite families of congruence relations modulo 2 for \(b_{13}(n)\). In addition, we will give an elementary proof of the parity result on broken 6-diamond partitions, which was established by Radu and Sellers. We also find a new congruence relation modulo 2 for the number of broken 6-diamond partitions of n. 相似文献
417.
Shaoyu Mai Prof. Dr. Qiuling Song 《Angewandte Chemie (International ed. in English)》2017,56(27):7952-7957
An efficient and convenient synthesis of valuable disulfanes and benzenesulfonothioates, having a 2-aminofuran framework, has been developed by employing a copper-catalyzed transformation of readily available N-tosylhydrazone-bearing thiocarbamates. This method features an inexpensive metal catalyst, mild reaction conditions, good functional-group tolerance, short reaction times, and delivers valuable and complex products. A copper carbene generated from an N-tosylhydrazone-bearing thiocarbamate is proposed as the key intermediate for the transformation and it triggers the subsequent cascade. Remarkably, the Ts anion released from N-tosylhydrazone further serves as a nucleophile, thus rendering the formation of benzenesulfonothioates under controlled conditions. 相似文献
418.
Cu/Fe‐Cocatalyzed Formation of β‐Ketophosphonates by a Domino Knoevenagel–Decarboxylation–Oxyphosphorylation Sequence from Aromatic Aldehydes and H‐Phosphonates
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Mingxin Zhou Yao Zhou Prof. Qiuling Song 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10654-10659
A domino Knoevenagel–decarboxylation–alkene difunctionalization sequence has been developed for the conversion of benzaldehydes into β‐ketophosphonates, catalyzed by a cooperative Cu/Fe system, whereby C?P and C?O bonds are formed simultaneously in a one‐pot reaction. The reaction proceeds in good yields and with a broad substrate scope and environmentally benign conditions. 相似文献
419.
Shen Qiuwan Jiang Yuhang Li Shian Yang Guogang Zhang Hongpeng Zhang Zhonggang Pan Xinxiang 《Journal of Sol-Gel Science and Technology》2021,99(2):420-429
Journal of Sol-Gel Science and Technology - Achieving efficient and stable hydrogen production has always been the focus of the industry, and ethanol steam reforming (ESR) is one of the most... 相似文献
420.
THE VOLUME AND TOPOLOGY OF A COMPLETE REIMANNIAN MANIFOLD 总被引:3,自引:0,他引:3
51. IntroductionAn importallt problem in memannian geometry is whether the manifold is of finite topological type. By it we mean that there is a compact domain fi C M such that M C fi ishomeomorphic to off x [0, co). If the manifold has nonnegative Ricci curvature, some important results have been obtained by mathematicans (see [1,3,4,5,6, etc.]). It is well knownthat if Ric(M)20, one has Gromvo-Bishop volume comparison theorem and for any givenPPM, r > 0,c(n)vol[B(P, 1)]rsvol[B(p, r)]sw… 相似文献