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Constructive proof on the existence of periodic solution of Duffing equation

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Chinese Science Bulletin 1997年第22期42卷 1870-1874页

作者： Li, wg Shen, ZH Nanjing Univ Dept Math Nanjing 210093 Peoples R China

CONSIDER the following boundary value problem of Duffing equation:{x(t)+Cx’(t)+g(t,x)=e(t), x(0)-x’(zπ)=x’(0)-x’(2π)=0,} (1)where g: R×R→R is continuous and continuously differentiable with respect to x, continu-ous and 2π-periodic with respect to t. C is a constant. e: R→R is continuous and 2π-period-ic. If there exist two almost everywhere continuous functions a(t), b(t)

关键词： Duffing equation periodic solution continuation.

Prognostic values of tumor endothelial markers in patients with colorectal cancer

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World Journal of Gastroenterology 2005年第9期11卷 1283-1286页

作者： KA Rmali MCA Puntis wg Jiang Metastasis and Angiogenesis Research Group University Department of Surgery

AIM: Tumor endothelial markers (TEMs) are a newly discovered family of endothelial markers associated with tumor specificangiogenesis. This study sought to examine the levels of expression (qualitatively and quantitatively)for TEMs in human colon ***: Human colorectal cancer tissues (n = 48)and normal background tissues (n = 31) were obtained after surgery. RNA was extracted from frozen sections for gene amplification. The expression of TEMs (TEM-1to TEM-8) was assessed using RT-PCR and their transcript levels were determined using real-time-quantitative PCR(Q-RT-PCR).RESULTS: TEM-1 (P = 0.01), TEM-7 (P = 0.04), TEM-7R(P= 0.03), TEM-8 (P = 0.001) significantly raised in colon cancer tissues compared with the levels detected in normal background tissues. The expressions of TEM-2 and TEM-6were found to be not significantly different between tumor tissues and normal tissues (P＞0.05). Patients who had cancer penetrating into and through the muscularis propria of the bowel wall and developed nodal involvement(Dukes C) exhibited significantly higher levels of TEM -8compared to patients who were node negative (P＜0.05).TEM-7 and TEM-7R showed high level of transcripts in Dukes C, but they were not statistically ***: The level of the expression of TEM-1,TEM-7, TEM-7R and TEM-8 (but not TEM-2 and TEM-6)were associated with both nodal involvement and disease progression, and may therefore, have a prognostic value in colorectal cancer.

关键词： Colon cancer Angiogenesis Tumor endothelial markers Dukes stages

Synthesis of dimethyl 3-perfluoroalkyl-4-(3-oxo-2-triphenyl-phosphoranylidenbutanylidene)-pent-2-enedioate and its cyclization

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Chinese Journal of Chemistry 1995年第5期13卷 468-474页

作者： Ding, WY Cao, wg Yao, Y Zhu, ZM SHANGHAI UNIV SCI & TECHNOL DEPT CHEMSHANGHAI 201800PEOPLES R CHINA

The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroalkynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (2) with acetylmethylenetriphenylphosphorane (1) at -5-0 degrees C. Intramolecular elimination of Ph(3)PO took place when compound 5 was heated in aqueous methanol at 115-120 degrees C in sealed tube, yielding dimethyl 2-trifluoromethyl-4-methylisophthalate (6a) from 5a and methyl 5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate (6b) from 5b, respectively. The structures of compounds 5, 6a and 6b were confirmed by IR, MS, H-1 NMR, F-19 NMR and C-13 NMR spectroscopy and elemental analyses. Rection mechanisms for the formation of compounds 5, 6a and 6b were proposed.

关键词： phosphorane polysubstituted arene intramolecular cyclization

Synthesis, structure and conformation of 1,3-difluorotetraphenyl benzene

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Chinese Journal of Chemistry 1996年第2期14卷 160-166页

作者： Zheng, ZR Pan, YM Liu, wg Huan, ZW NANKAI UNIV DEPT CHEMNATL KEY LAB ELEMENTOORGAN CHEMTIANJIN 300071PEOPLES R CHINA

The compound trifluoroiodomethane can be activated to react with the electron donor, 1,4-dilithiotetraphenyl butadiene, by means of electron transfer catalysis (ETC). The structure of the product, 1,3-difluorotetraphenyl, benzene (1), was determined by MS, NMR, and X-ray single crystal diffraction. The conformations of compound 1 and its derivatives were analysized by molecular mechanics.

关键词： tetraphenylbenzene conformation molecular mechanics

Is EAAT2 a potential therapeutic intervention target for Alzheimer's disease?

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Neural Regeneration Research 2023年第8期18卷 1721-1722页

作者： Oliver wg Wood Jason HY Yeung Andrea Kwakowsky Centre for Brain Research Department of Anatomy and Medical ImagingFaculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreOllscoil na Gaillimhe-University of GalwayGalwayIreland

Alzheimer's disease(AD)is the most common form of dementia worldwide,impairing memory and cognitive functions due to widespread neuronal *** global incidence of this neurodegenerative disorder is predicted to increase... 详细信息

关键词： Alzheimer death EAAT2

Electronic structure and fluorescent property of endohedral terbium fullerenes

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Chinese Science Bulletin 1997年第21期42卷 1798-1802页

作者： Sun, DY Liu, ZY Guo, XH Xu, wg Liu, SY Chinese Acad Sci Changchun Inst Appl Chem State Key Lab Appl Chem Changchun 130022 Peoples R China

ENDOHEDRAL metallofullerencs is the important part of modern fullerene science *** the first determination of La@C2n, in laser mass spectrometry till now, great progresshas been made in this field. Varieties of endohedral metallofullerenes have been synthesizedby using arc evaporation method. The subsequent purification, characterization and derivatiza-

关键词： metallofullerenes terbium XPS fluorescent spectroscopy.

Isotopic compositions of chlorine in brine and saline minerals

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Chinese Science Bulletin 1997年第5期42卷 406-409页

作者： Xiao, YK Liu, wg Zhou, YM Sun, DP Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining China

CHLORINE in the nature has two stable isotopes, 35Cl and 37Cl. Two methods of determining isotopic ratios of chlorine were once developed. Owen, Kaufmann and Long determined 37Cl/35Cl ratios based on the measurement of CH3Cl+ ion produced by ionization of methyl chlorine. The precision of the measurement of Cl-（NTIMS） was reported by Shields and Vengosh. The NTIMS has less precision.

关键词： brine saline mineral chlorine isotope fractionation.

The mean properties and variations of the Southern Hemisphere subpolar gyres estimated by Simple Ocean Data Assimilation(SODA) products

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Acta Oceanologica Sinica 2016年第7期35卷 8-13页

作者： DUAN Yongliang LIU Hongwei YU Weidong hou Yijun Center for Ocean and Climate Research First Institute of OceanographyState Oceanic Administration Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences

Based on the Simple Ocean Data Assimilation （SODA） products, we study the mean properties and variations of the Southern Hemisphere subpolar gyres （SHSGs） in this paper. The results show that the gyre strengths in the SODA estimates are （55.9±9.8）×108 ma/s for the Weddell Gyre （wg）, （37.0±6.4） ×106 ma/s for the Ross Gyre （RG）, and （27.5±8.2）x 106 ma/s for the Australian-Antarctic Gyre （AG）, respectively. There exists distinct connectivity between the adjacent gyres and then forms an oceanic super gyre structure in the southern subpolar oceans. And the interior exchanges are about （8.0±3.2）× 106 ma/s at around 70°E and （4.3±3.1）× 106 m3/s at around 140°E. The most pronounced variation for all three SHSGs occurs on the seasonal time scale, with generally stronger （weaker） SHSGs during austral winter （summer）. And the seasonal changes of the gyre structures show that the eastern boundary of the wg and AG extends considerably further east during winter and the interior exchange in the super gyre structure increases accordingly. The wg and RG also show significant semi-annual changes. The correlation analyses confirm that the variations of the gyre strengths are strongly correlated with the changes in the local wind forcing on the semi-annual and seasonal time scales.

关键词： the subpolar gyres Southern Ocean wind stress wind stress curl

A Model for Liquid-Diffusion Catalytically Grown Fibrous Carbon Material

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Journal of Materials Science & Technology 1999年第1期15卷 1-4页

作者： Zhang, wg Cheng, HM Su, G Fan, YY Li, F Shen, ZH Zhou, BL Chinese Acad Sci Met Res Inst Shenyang 110015 Peoples R China

A mechanism for the catalytically growth of vapor grown fibrous carbon (VGFC) preparing from the floating catalyst method has been proposed, in which liquid diffusion-determined diffusion of carbon atoms through catalyst particles is described mathematically, and the physical and chemical properties of the catalyst particles during the growth process are taken into account. From the model the growth rate and grown length of VGFC are calculated theoretically which coincides with the experimental data; and the necessity of reducing gas such as hydrogen in preparing VGFC is explained as to reduce Fe3C, which acts as intermediate catalyst shown by the model. Fe3C formed on the surface of gamma-Fe will stop the growth of carbon fiber if they can not be reduced at once. Additionally, the growth temperature and diameter of VGFC are also discussed in the paper.

关键词： Li Cs A Model for Liquid-Diffusion Catalytically Grown Fibrous Carbon Material