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A new triterpenoid saponin from Clematis ganpiniana

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Chinese Chemical Letters 2007年第9期18卷 1078-1080页

作者： Feng Sun qing He Pei Gen Xiao Yi yu cheng Pharmaceutical Informatics Institute College of Pharmaceutical Sciences Zhejiang University Hangzhou 310027 China Institute of Medicinal Plant Development Chinese Academy of Medical Sciences Beijing 100094 China

A new triterpenoid saponin, named clematiganoside A (1), was isolated from the whole plant of Clematis ganpiniana. Its structure was elucidated on the basis of 1D, 2D NMR, TOF-MS and ESI-MS techniques, and physicochem... 详细信息

关键词： Clematis ganpiniana Triterpenoid saponin Clematiganoside A

Numerical simulation of hydraulic fracture propagation in tight oil reservoirs by volumetric fracturing

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Petroleum Science 2015年第4期12卷 674-682页

作者： Shi-cheng Zhang Xin Lei yu-Shi Zhou Guo-qing Xu College of Petroleum Engineering University of Petroleum

Volumetric fracturing is a primary stimulation technology for economical and effective exploitation of tight oil reservoirs. The main mechanism is to connect natural fractures to generate a fracture network system which can enhance the stimulated reservoir volume. By using the combined finite and discrete element method, a model was built to describe hydraulic fracture propagation in tight oil reservoirs. Considering the effect of horizontal stress difference, number and spacing of perforation clus- ters, injection rate, and the density of natural fractures on fracture propagation, we used this model to simulate the fracture propagation in a tight formation of a certain oil- field. Simulation results show that when the horizontal stress difference is lower than 5 MPa, it is beneficial to form a complex fracture network system. If the horizontal stress difference is higher than 6 MPa, it is easy to form a planar fracture system; with high horizontal stress differ- ence, increasing the number of perforation clusters is beneficial to open and connect more natural fractures, and to improve the complexity of fracture network and the stimulated reservoir volume （SRV）. As the injection rate increases, the effect of volumetric fracturing may be improved; the density of natural fractures may only have a great influence on the effect of volume stimulation in a low horizontal stress difference.

关键词： Tight oil reservoir Volumetric fracturingFracture propagation Horizontal stress difference Stimulated reservoir volume

Fault Detection for a Class of Impulsive Switched Systems

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International Journal of Automation and computing 2014年第2期11卷 223-230页

作者： qing-yu Su Yan-cheng Li Xing-Ze Dai Jian Li School of Automation Engineering Northeast Dianli University

The problem of fault detection for a class of nonlinear impulsive switched systems is investigated in this paper. Fault detection filters are designed such that the augmented systems are stable, and the residual error signal generated by the filters guarantees the H∞ performance for disturbances and faults. Sufficient conditions for the design of fault detection(FD) filters are presented by linear matrix inequalities. Moreover, the filter gains are characterized according to a solution of a convex optimization. Finally, an example derived from a pulse-width-modulation-driven boost converter is given to illustrate the effectiveness of the FD design approach.

关键词： Impulsive switched systems fault detection(FD) H∞ performance dwell time filter design.

Radio frequency conditioning of an S-band accelerating structure prototype for compact proton therapy facility

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Nuclear Science and Techniques 2021年第6期32卷 94-107页

作者： yu Zhang Wen-cheng Fang Xiao-Xia Huang Jian-Hao Tan Shao-Peng Zhong cheng-cheng Xiao Jun-Qiang Zhang cheng Wang yu-qing Yang Zhen-Tang Zhao Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Shanghai Tech University Shanghai 201210China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China

The development of a high-gradient accelerating structure is underway to construct a compact proton linear accelerator for cancer *** experiments and numerous studies are being conducted to develop compact linear accelerators for proton *** of the electromagnetic and mechanical design has been performed to simplify the manufacturing process and reduce costs.A novel high-gradient structure with a low relativistic proton velocity(β),v/c=0.38,was designed,fabricated,and tested at high *** first full-scale prototype was also successfully tested with high radio frequency(RF)power,a repetition rate of 50 Hz,and pulse length of 3μs to reach a high-gradient of 46 MV/m using a 50 MW S-band klystron power supply obtained from the Shanghai Soft X-ray Free Electron Laser *** is the first high-power test in China,which is in line with the expected experimental *** study presents preliminary high-power testing of S-band standing wave accelerating structures with 11 *** work aims to verify the feasibility of using a high-gradient RF accelerating structure in compact proton therapy *** cold test of the prototype cavity was completed in *** of the high-power RF test setup,the process of RF conditioning,and the high-power results are described.

关键词： S-band Standing wave(SW) High-gradient Accelerating structure RF conditioning

Analytical expression for betatron tune shift due to field errors in lump quadrupole

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Nuclear Science and Techniques 2016年第1期27卷 5-7页

作者： yuan Chen cheng-Hui yu qing Qin Jiu-qingWang Shou-Xian Fang Institute of High Energy Physics Chinese Academy of Sciences

The integrated gradient of a quadrupole will be deviated by a close neighboring sextupole, and this is called the effect of fringe field interference. Using the Lie algebra techniques, an analytical expression for the betatron tune shift due to this effect has been derived. The process does not depend on the supposition of the thin-lens quadrupoles. It can be used to estimate the tune shift differences between the designed lattice and the one including the fringe field interference. More generally, the method can be applied to other kinds of fringe field interference.

关键词：解析表达式四极杆场误差电场干扰李代数方法 Tron 薄透镜密相

High-temperature corrosion of Sn-Bi-Zn-Ga alloys as heat transfer fluid

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Rare Metals 2021年第8期40卷 2221-2229页

作者： qing-Meng Wang Xiao-Min cheng yuan-yuan Li Guo-Ming yu Zhi Liu School of Materials Science and Engineering Wuhan University of TechnologyWuhan430070China School of Mechanical and Electrical Engineering Huanggang Normal UniversityHuanggang438000China

The new heat transfer alloy is highly reactive at high temperatures,and the corrosion of the container material determines the service life of the heat transfer *** high-temperature corrosion of Sn-Bi-Zn-Ga alloys as heat transfer fluid was *** microstructure and elemental distribution were studied by field emission scanning electron microscopy(FESEM)and energy dispersive spectroscopy(EDS).The thermal properties before and after corrosion were studied by differential scanning calorimetry(DSC).The results show that the corrosion kinetics of the studied materials follows the parabolic law and the thermal properties after corrosion are *** significantly improves the thermal conductivity.316 stainless steel exhibits excellent corrosion resistance due to its high Cr and Ni *** mechanism analysis shows that the oxidation of Ga has a smaller Gibbs free energy,and an oxide forms at the corrosion interface to prevent dissolution corrosion and oxidative corrosion of the container material.

关键词： Sn-Bi-Zn-Ga Heat transfer fluids Thermophysical properties High-temperature corrosion

Dual modification of LiNi_(0.83)Co_(0.11)Mn_(0.06)O_(2) cathode materials by K^(+) doping and Li_(3)PO_(4) coating for lithium ions batteries

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Rare Metals 2024年第7期43卷 3007-3018页

作者： Wei Xiao Jia-Le Wang Zhi-cheng Yi cheng-Jin Liu Chang Miao yu Xin Shu-qing Nie College of Chemistry and Environmental Engineering Yangtze UniversityJingzhou 434023China

Li_(3)PO_(4)@Li_(0.99)K_(0.01)Ni_(0.83)Co_(0.11)Mn_(O.06)O_(2)(NCM-KP) cathode powders are synthesized via K^(+)doping in calcination processes and H_3PO_4 coating in sol-gel processes.K^(+) precisely enters into the lattice to widen the(003) plane to 0.4746 nm with a lower cationic disordered degree of 1.87%.Moreover,the surface residual lithium salts are treated by H_3PO_4 to generate a uniform Li_(3)PO_(4) coating layer of approximately 11.41 nm,which completely covers on the surface of secondary spherical particles to improve the interfacial *** 25℃,the NCM-KP electrode delivers a discharge specific capacity of 148.9 mAh·g^(-1) with a remarkable capacity retention ratio of 84.1% after 200 cycles at 1.0C and retains a high reversible specific capacity of 154.4 mAh·g^(-1) at *** at 1.0C and 60℃,it can maintain a reversible discharge specific capacity of 114.6 mAh·g^(-1) with 0.21% of capacity decay per cycle after 200 cycles,which is significantly lower than 0.40% for the pristine NCM ***,the charge transfer resistance of 238.89 Ω for the NCM-KP electrode is significantly lower than 947.41 Ω for the pristine NCM one by restricting the interfacial side ***,combining K+doping and Li_(3)PO_(4) coating is an effective strategy to enable the significant improvement of the electrochemical property of high-nickel cathode materials,which may be mainly attributed to the widened diffusion pathway and the formed Li_(3)PO_(4) protective layer,thus promoting Li~+diffusion rate and preventing the erosion of HF.

关键词： High-nickel cathode material Residual lithium K^(+)doping Li_(3)PO_(4)coating Lithium ions battery

Higher-dimensional integrable deformations of the classical Boussinesq-Burgers system

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Communications in Theoretical Physics 2024年第6期76卷 1-12页

作者： Xiaoyu cheng qing Huang School of Mathematics Northwest UniversityXi'an 710127China

In this paper,the(1+1)-dimensional classical Boussinesq-Burgers(CBB)system is extended to a(4+1)-dimensional CBB system by using its conservation laws and the deformation *** Lax integrability,symmetry integrability and a large number of reduced systems of the new higher-dimensional system are ***,for illustration,an exact solution of a(1+1)-dimensional reduced system is constructed from the viewpoint of Lie symmetry analysis and the power series method.

关键词： classical Boussinesq-Burgers system higher-dimensional system deformation algorithm Lax pair conservation law

Selective mono-arylation in palladium-catalyzed cross-coupling reaction of dichlorotriazines with phenylboronate ester derivatives

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Chinese Chemical Letters 2013年第1期24卷 41-44页

作者： Jin-Fu Dong Xin yu cheng-qing Ning Liang Hu Nie-Fang yu School of Pharmaceutical Sciences Central South University School of Pharmaceutical Sciences Sun Yat-sen University

Palladium-catalyzed cross-coupling reaction between dichlorotriazines and phenylboronate esters produced the mono-awlated triazines selectively and thus, the corresponding phenyltriazine derivatives could be assembled... 详细信息

关键词： Suzuki cross-coupling reactionDichlorotriazinesAryl boronic estersPd(PPh3)4