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On the Period Variation of the W UMa-type Contact Binary V502 Ophiuchi

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Chinese Journal of Astronomy and Astrophysics 2006年第3期6卷 331-337页

作者： Qing-Yao liu yu-Lan yang National Astronomical Observatories/yunnan Observatory Chinese Academy of Sciences Kunming 650011

The variation in the orbital period of the W UMa type contact binary V502 Oph is analyzed. The orbital period exhibits a wavelike variation with a periodicity of 23.0 years and an amplitude of AP = 1.24 ×10^-5 days superimposed on secular decrease of dP/dt = 1.68× 10^-7 day per year. The long-term decrease may be accompanied by the contraction of the secondary at a rate of 83 m per year and a mass transfer rate from the primary to the secondary of 4.28×10^-8M· per year. The short-term oscillation may be explained by the presence of a third component. Orbital elements of the third body and its possible mass are presented.

关键词： stars: contact binary - period change - star: individual: V502 Oph

Study of the permeability characteristics of porous media with methane hydrate by pore network model

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Journal of Natural Gas Chemistry 2010年第3期19卷 255-260页

作者： Haifeng Liang Yongchen Song yu liu Mingjun yang Xing Huang Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian 116024 Liaoning China

The permeability in the methane hydrate reservoir is one of the key parameters in estimating the gas production performance and the flow behavior of gas and water during *** this paper,a three-dimensional cubic pore-network model based on invasion percolation is developed to study the effect of hydrate particle formation and growth habit on the *** variation of permeability in porous media with different hydrate saturation is studied by solving the network *** simulation results are well consistent with the experimental *** proposed model predicts that the permeability will reduce exponentially with the increase of hydrate saturation,which is crucial in developing a deeper understanding of the mechanism of hydrate formation and dissociation in porous media.

关键词： pore network model hydrate saturation permeability porous media

Cerium-tannic acid passivation treatment on galvanized steel

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Rare Metals 2009年第3期28卷 284-288页

作者： liu Guangming yu Fei yang liu TIAN Jihong DU Nan Key Laboratory of Nondestructive Testing （Nanchang Hangkong University） Ministry of Education of China Nanchang 330063 China School of Aeronautic and Mechanical Engineering Nanchang Hangkong University Nanchang 330063 China

A novel cerium-tannic acid passivation treatment was performed on galvanized steel. The corrosion resistance of cerium-tannic passivated samples was tested by dropping test with 0.5 wt.% CuSO4 aqueous solution. The mass loss per unit area of passivated samples was measured after the corrosion in 0.5 mol/L NaCl ＋ 0.005 mol/L H2SO4 at room temperature for 96 h. The electrochemical behaviors of cerium, tannic acid, and cerium-tannic acid passivated samples on galvanized steel in 0.5 mol/L NaCl solution were investigated by polarization curves and electrochemical impendence spectra. The corrosion equivalent circuit was established according to the impedance characteristics. The results show that cerium-tannic acid treated samples exhibit better corrosion resistance than the sole cerium or tannic acid treated samples under the same condition. The mechanism of synergistic effect for cerium-tannic acid passivation on galvanized steel was discussed.

关键词： passivation cerium tannic acid galvanized steel corrosion

Synthesis and Tumor Cytotoxicity of Novel N-Substituted Glucosamine-bearing Oleanolic Acid Derivatives

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Chemical Research in Chinese Universities 2014年第4期30卷 639-643页

作者： REN Li liu yang yu Guihua GAO yuan liu Xin WANG Bo DENG Xiaonan CHENG Maosheng Key Laboratory of Structure-based Drug Design and Discovery Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 P. R. China

Eleven novel triterpenoid saponins,N-substituted-β-D-glucosaminide derivatives of oleanolic acid,were designed and synthesized via a stepwise glycosylation *** compounds were evaluated for in vitro cytotoxic activity against six different tumor cell *** of the compounds inhibited the growth of,at least,one tumor cell line effectively at micromolar *** structure-activity relationships（SARs） indicate that acylation of the nitrogen of the glucosamine-bearing triterpenoid saponins affords the compounds that are highly cytotoxic towards specific tumor cell lines.

关键词： N-Substituted glucosamine-bearing triterpenoid saponin Tumor cytotoxicity Oleanolic acid

Application of Current Hapten in the Production of Broad Specificity Antibodies Against Organophosphorus Pesticides

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Agricultural Sciences in China 2008年第11期7卷 1341-1347页

作者： liu Xian-jin YAN Chun-rong liu yuan yu Xiang-yang ZHANG Cun-zheng Food Safety Research and Inspection Center Jiangsu Academy of Agricultural Sciences Nanjing 210014 P.R. China

Diethylphosphono acetic acid （DPA） was used as a current hapten to generate broad specificity polycolonal antibodies against a group of organophosphorus pesticides. Six New Zealand white rabbits were immunized with immunogens synthesized by the active ester method （AEM） or 1-ethyl-3-（3-dimethylaminopropyl）-carbodimide method （EDC）. The titers of antisera reached 25 600 by AEM and 6 400 by EDC, respectively. Polyclonal antibodies raised against DPA were screened and selected for the competitive indirect enzyme-linked immunosorbent assay （CI-ELISA）. A CI-ELISA for DPA was developed with a detection limit of 3.536 ng mL^-1and an I50 value of 0.182 μg mL^-1. The assay specificity was evaluated by obtaining competitive curves for several structurally related compounds as competitors. The antiserum showed high affinities to chlorpyrifos, diazinon, omethoate, parathion-ethyl and profenofos with I50 of 0.12, 0.15, 0.21, 0.88, 0.97 and 2.5 μg mL^-1, respectively. The results indicate that the assay could be a screening tool for quantitation and semiquantitation determination of the above former five organophosphorus pesticides.

关键词： organophosphorus pesticides broad specificity antibody enzyme-linked immunosorbent assay (ELISA)

Profile and prevalence of aspirin resistance in patients with metabolic syndrome

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Journal of Geriatric Cardiology 2008年第1期5卷 7-10页

作者： Zhaoping liu yang yu yuanjie Mao Xinhua Wang Jianzhong Wang Yong Huo Department of Cardiology Peking University First HospitalBeijing 100034China Department of CardiologyPeking University First HospitalBeijing 100034China Department of CardiologyPeking University First HospitalBeijing 100034China Department of Clinical LaboratoryPeking University First HospitalBeijing 100034China Department of Clinical LaboratoryPeking University First HospitalBeijing 100034China Department of CardiologyPeking University First HospitalBeijing 100034China

Objective Aspirin has been used extensively in primary and secondary prevention of cardiovascular disease,particularly for subjects at high risk such as metabolic ***,the responsiveness to aspirin treatment may vary among *** present study was conducted to investigate the profile and prevalence of aspirin resistance in patients with metabolic *** In 221 consecutive patients,platelet aggregation induced by arachidonic acid (0.5mg/ml) was assessed after 10 days of aspirin treatment (200mg/d).Aspirin resistance was defined as mean optical platelet aggregation =20%.Results Aspirin resistance occurred in 39 patients (17.6%).Serum fibrinogen level was higher in patients with than in those without aspirin resistance (2.6_+0.4g/l vs 2.4±0.4g/L,P=0.017).The 2 groups,aspirin resistance group and no aspirin resistance group,did not differ significantly,with regard to gender,age,body mass index,waist-hip ratio,blood pressure level,serum cholesterol level and history of myocardial or cerebral *** logistic regression analysis revealed that only serum fibrinogen level entered the model (odds ratio 2.973,p=0.023).Subgroup analysis further showed that aspirin resistance occurred more in male patients with myocardial infarction (50% vs14.5%,P=0.02) and in female patients with diastolic blood pressure=85mmHg (34% vs 15.5%,P=0.043).But after multifactor logistic regression,in women blood pressure=85mmHg was not a predictor any *** In patients with metabolic syndrome,aspirin resistance is not uncommon,especially for men with history of myocardial *** with aspirin resistance have an increased serum fibrinogen level.(J Geriatr Cardio12008;5:7-10)

关键词： metabolic syndrome aspirin resistance fibrinogen

Petrel2ANSYS: Accessible software for simulation of crustal stress fields using constraints provided by multiple 3D models employing different types of grids

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Journal of Central South University 2019年第9期26卷 2447-2463页

作者： liu yu-yang PAN Mao liu Shi-qi School of Earth and Space Science Peking UniversityBeijing 100871China The Key Laboratory of Orogenic Belts and Crustal Evolution(MOE) Peking UniversityBeijing 100871China

Crustal stresses play an important role in both exploration and development in the oil and gas ***,it is difficult to simulate crustal stress distributions accurately,because of the incompatibilities that exist among different ***,a series of algorithms is developed and integrated in the Petrel2ANSYS to carry out two-way conversions between the 3D attribute models that employ corner-point grids used in Petrel and the 3D finite-element grids used in ***,a modified method of simulating stress characteristics and analyzing stress fields using the finite-element method and multiple finely resolved 3D models is *** to the traditional finite-element simulation-based approach,which involves describing the heterogeneous within a rock body or sedimentary facies in detail and simulating the stress distribution,the single grid cell-based approach focuses on a greater degree on combining the rock mechanics described by 3D corner-point grid models with the finely resolved material characteristics of 3D finite-element *** models that use structured and unstructured grids are verified in Petrel2ANSYS to assess the *** addition,with minor modifications,platforms based on the present algorithms can be extended to other models to convert corner-point grids to the finite-element grids constructed by other software.

关键词： numerical simulation of stress fields corner-point grids finite-element grids Petrel ANSYS

Diverse sesquiterpenoids from Litsea lancilimba *** potential neuroprotective effects against H_(2)O_(2)-induced SH-SY5Y cell injury

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Chinese Journal of Natural Medicines 2022年第9期20卷 701-711页

作者： ZHANG Yi-Jie BAI Ming LI Jia-Yi QIN Shu-Yan liu yu-yang HUANG Xiao-Xiao ZHENG Jiang SONG Shao-Jiang Key Laboratory of Computational Chemistry-Based Natural Antitumor Drug Research&Development Liaoning ProvinceEngineering Research Center of Natural Medicine Active Molecule Research&DevelopmentLiaoning ProvinceKey Laboratory of Natural Bioactive Compounds Discovery&ModificationShenyangSchool of Traditional Chinese Materia MedicaShenyang Pharmaceutical UniversityShenyang 110016China Wuya College of Innovation Shenyang Pharmaceutical UniversityShenyang 110016China State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Provincial Key Laboratory of PharmaceuticsGuizhou Medical UniversityGuiyang 550004China

Five undescribed sesquiterpenoids(1–5),and nine known sesquiterpenoids(6–14)were obtained from the fruits of Litsea lancilimba *** LC-MS/MS molecular networking *** A(1)possessed a unique 8-member ring through unexpected cyclization of the methyl group on C-10 of *** structures were elucidated by spectroscopic techniques including IR,UV,NMR,HR-ESI-MS,and their absolute configurations were assigned by ECD *** isolated sesquiterpenoids were analyzed by bioinformatics and evaluated for their neuroprotective effects against H_(2)O_(2)-induced injury in human neuroblastoma SH-SY5Y cells.

关键词： Litsea lancilimba Lauraceae Sesquiterpenoids Neuroprotective effect

Low-cost and fluoride-free synthesis of MFI zeolite nanosheets with enhanced stability for benzene alkylation with ethanol

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Journal of Energy Chemistry 2025年第1期100卷 458-468页

作者： Peng Zhu Cun liu Yiren yu Guoshu Gao yumeng Zhao Xiongfu Zhang Guodong liu Guohui yang State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences

Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented *** obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.

关键词： MFI zeolite ZSM-5 Nanosheets Scale-up synthesis Aromatic alkylation