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Integral precession calibration method of PIGA on linear vibration table

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Chinese Journal of Aeronautics 2024年第3期37卷 219-236页

作者： chuang SUN Shun-qing REN Jun-wei CAO Ru HUO Department of Automation Tsinghua UniversityBeijing 100084China School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Faculty of Information technology Beijing University of TechnologyBeijing 100124China

Linear vibration table can provide harmonic accelerations to excite the nonlinear error terms of Pendulous Integrating Gyro Accelerometer(PIGA).Integral precession calibration method is proposed to calibrate PIGA on a linear vibration table in this *** on the precise expressions of PIGA’s inputs,the error calibration model of PIGA is *** angular velocity errors of PIGA are suppressed by integer periodic precession and the errors caused by non-integer periods vibrating are *** complete calibration process,including planning,preparation,PIGA testing,and coefficient identification,is designed to optimize the test operations and evaluate the calibration *** effect of the main errors on calibration uncertainty is analyzed and the relative sensitivity function is proposed to further optimize the test *** and simulation results verify that the proposed 10-position calibration method can improve calibration uncertainties after compensating for the related *** order of calibration uncertainties of the second-and third-order coefficients are decreased to 10^(-8)(rad.s^(-1))/g^(2)and 10^(-8)(rad.s^(-1))/g3,*** with the other two classical calibration methods,the calibration uncertainties of PIGA’s nonlinear error coefficients can be effectively reduced and the proportional residual errors are decreased less than 3×10-6(rad.s^(-1))/g by using the proposed calibration method.

关键词： PIGA Linear vibration table Vibration measurement Calibration Error analysis Uncertainty analysis

Multiple damage zones around hydraulic fractures generated by high-frequency pulsating hydraulic fracturing

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Petroleum Science 2024年第4期21卷 2688-2702页

作者： Yan Peng Sheng-Jie wei Guang-Qing Zhang Da-wei Zhou chuang-Chao Xu School of Petroleum Engineering China University of Petroleum PetroChina Changqing Oilfield Company

Pulsating hydraulic fracturing(PHF) is a promising fracturing method and can generate a dynamic periodic pressure. The periodic pressure can induce fatigue failure of rocks and decrease initiation pressure of fracture. If the frequency of periodic pressure exceeds 10 Hz, the distribution of pressure along the main fracture will be heterogeneous, which is much different from the one induced by the common fracturing method. In this study, the impact of this special spatial feature of pressure on hydraulic fracture is mainly investigated. A coupled numerical simulation model is first proposed and verified through experimental and theoretical solutions. The mechanism of secondary fracture initiation around the main fracture is then discovered. In addition, sensitivity studies are conducted to find out the application potential of this new method. The results show that(1) this coupled numerical simulation model is accurate. Through comparison with experimental and theoretical data, the average error of this coupled model is less than 1.01%.(2) Even if a reservoir has no natural fracture, this heterogeneous distribution pressure can also cause many secondary fractures around the main fracture.(3) The mechanism of secondary fracture initiation is that this heterogeneous distribution pressure causes tensile stress at many locations along the main fracture.(4) Through adjusting the stimulation parameters, the stimulation efficiency can be improved. The average and amplitude of pressure can increase possibility of secondary fracture initiation. The frequency of this periodic pressure can increase number of secondary fractures. Even 6 secondary fractures along a 100 m-length main fracture can be generated.(5) The influence magnitudes of stimulation parameters are larger than ones of geomechanical properties, therefore, this new fracturing method has a wide application potential.

关键词： Tight reservoir Reservoir stimulation Numerical simulation Secondary fracture Fracture initiation

High-frequency Resonance Analysis and Impedance Reshaping Control of MMC-HVDC System Based on Frequency Coupling Impedance Model

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 646-657页

作者： Juanjuan Wang wei Chen Yuekun Liu chuang Fu Yunming Ye Junjie Feng School of Electric Power South China University of TechnologyGuangzhouChina Guangdong Power Grid Co. Ltd.GuangzhouChina Electric Power Research Institute China Southern Power GridGuangzhouChina

In recent years, high-frequency resonance (HFR) events occurred in several modular multilevel converter based high-voltage direct current (MMC-HVDC) projects. The time delay of an MMC-HVDC system is the critical factor that induces HFR. The frequency coupling affects the impedance characteristics of an MMC and further deteriorates system stability. Therefore, in this paper, a multi-input multi-output admittance model of an MMC-HVDC system is developed to analyze its frequency characteristics. The effects of current loop, power loop, phase-locked loop, and operating point on the MMC frequency coupling degree are analyzed in detail. Meanwhile, to further suppress HFR in the MMC-HVDC system, an enhanced impedance reshaping control strategy based on the equivalent single-input single-output impedance model is proposed. Finally, the accuracy of the enhanced impedance model and the effectiveness of the impedance reshaping control are verified by electromagnetic transient simulations in PSCAD.

关键词： Modular multilevel converter based high-voltage direct current(MMC-HVDC) high-frequency resonance frequency coupling impedance model impedance reshaping control

Adaptive mutation sparrow search algorithm-Elman-AdaBoost model for predicting the deformation of subway tunnels

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Underground Space 2024年第4期17卷 320-360页

作者： Xiangzhen Zhou wei Hu Zhongyong Zhang Junneng Ye chuang Zhao Xuecheng Bian MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou 310058China Hangzhou Canal Group Construction Management Co.LTD Hangzhou 310015China Ningbo Rail Transit Project Construction Headquarter Ningbo 315012China Center for Hypergravity Experimental and Interdisciplinary Research Zhejiang UniversityHangzhou 310058China

A novel coupled model integrating Elman-AdaBoost with adaptive mutation sparrow search algorithm(AM-SSA),called AMSSAElman-AdaBoost,is proposed for predicting the existing metro tunnel deformation induced by adjacent deep excavations in soft *** novelty is that the modified SSA proposes adaptive adjustment strategy to create a balance between the capacity of exploitation and *** AM-SSA,firstly,the population is initialized by cat mapping chaotic sequences to improve the ergodicity and randomness of the individual sparrow,enhancing the global search *** the individuals are adjusted by Tent chaotic disturbance and Cauchy mutation to avoid the population being too concentrated or scattered,expanding the local search ***,the adaptive producer-scrounger number adjustment formula is introduced to balance the ability to seek the global and local *** addition,it leads to the improved algorithm achieving a better accuracy level and convergence speed compared with the original *** demonstrate the effectiveness and reliability of AM-SSA,23 classical benchmark functions and 25 IEEE Congress on Evolutionary Computation benchmark test functions(CEC2005),are employed as the numerical examples and investigated in comparison with some wellknown optimization *** statistical results indicate the promising performance of AM-SSA in a variety of optimization with constrained and unknown search *** utilizing the AdaBoost algorithm,multiple sets of weak AMSSA-Elman predictor functions are restructured into one strong predictor by successive iterations for the tunnel deformation prediction ***,the on-site monitoring data acquired from a deep excavation project in Ningbo,China,were selected as the training and testing ***,the predictive outcomes are compared with those of other different optimization and machine learning *** the end,the obtained results in this real-world geotechnical eng

关键词： Adjacent deep excavations Existing subway tunnels Adaptive mutation sparrow search algorithm Metaheuristic optimization Benchmark test functions Elman neural networks

Effect of Preload Force on Heat Generation of Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2)/SiO_(x)-C System Batteries:The Discharge Process

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Journal of Thermal Science 2024年第5期33卷 1809-1825页

作者： LIN Chunjing LAI Zhenxing BAI Guangli MA Biao wei Zhen QI chuang LIU Shiqiang Key Laboratory of Advanced Manufacturing Technology for Automobile Parts Ministry of EducationChongqing University of TechnologyChongqing 400054China China Auto Research New Energy Vehicle Inspection Center(Tianjin)Co Tianjin 300300China

Lithium-ion batteries(LIBs)undergo various degradation phenomena such as material decomposition,structural change and uneven lithium ion distribution during long-term cycles,which would affect their performance and *** order to improve the performance of the LIBs during their life cycle,preload force is preset when the batteries are *** preload forces will in turn affect the cycle life and heat generation of the *** order to address this issue,this work carries out charge/discharge cycle tests on a NCM811 battery under different preload *** calorimetry tests are performed to investigate the battery heat generation under different states of health(SOHs)and preload *** on the test results,an empirical prediction model for heat generation power as a function of SOH is *** show that when the preload force is 5 N·m,the battery capacity decreases in the slowest rate and the average heat generation power is the *** in peaks of the incremental capacity curve can be used to characterize the loss of lithium at the electrode,which in turn characterizes the change of heat generation power of the *** average heat generation power is mainly affected by the SOH,going through a period of trough with the decrease of the SOH and continuing to increase after crossing the critical *** general,these findings emphasize the relationship between preload force,SOH and heat generation power,which is helpful for the judgment of optimal preload to improve the efficiency of LIBs.

关键词： lithium ion battery cyclic aging preload force heat generation characteristic

Improved performance of LiMn_(0.8)Fe_(0.2)PO_(4) by addition of fluoroethylene carbonate electrolyte additive

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Chinese Chemical Letters 2024年第6期35卷 229-233页

作者： Guihuang Fang wei Chen Hongwei Yang Haisheng Fang chuang Yu Maoxiang Wu Faculty of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming 650093China Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The addition of electrolyte additives is an effective strategy for tuning the property of the electrolyte to engineer the electrode/electrolyte interface,and there exist obvious discrepancies regarding the effect of fluoroethylene carbonate(FEC)as an electrolyte additive on the performance of *** FEC is introduced into the electrolyte of the LiMn_(0.8)Fe_(0.2)PO_(4)/Li cell and its effect on the properties of the LiMn_(0.8)Fe_(0.2)PO_(4) is *** is found that the addition of FEC in the electrolyte has a positive effect on the performance of the LiMn_(0.8)Fe_(0.2)PO_(4) cathode,which can be attributed to the reduced products generated by the interfacial side-reactions on the LiMn_(0.8)Fe_(0.2)PO_(4) cathode surface and the decreased metal dissolution in the FEC-containing electrolyte,thanks to the higher oxidation resistance of FEC and the easier and stronger binding of FEC and PF_6^(-).

关键词： Lithium-ion batteries LiMn_(0.8)Fe_(0.2)PO_(4) Cathode Electrolyte additives Fluoroethylene carbonate

Epitaxial growth of borophene on graphene surface towards efficient and broadband photodetector

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Nano Research 2024年第4期17卷 3053-3060页

作者： Zenghui Wu Chen Shifan Zitong Wu Yi Liu wei Shao Xinchao Liang chuang Hou Guoan Tai The State Key Laboratory of Mechanics and Control of Mechanical Structures and Laboratory of Intelligent Nano Materials and Devices of Ministry of Education College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

In-situ integration of multiple materials with well-defined interfaces as heterostructures is of great interest due to their unique properties and potential for new device *** of its polymorphism and diverse bonding geometries,borophene is a promising candidate for two-dimensional heterostructures,but suitable synthesis conditions have limited its potential *** this end,we demonstrate the vertical borophene and graphene heterostructures which form by epitaxial growth of borophene onto multilayer graphene on Cu substrates via chemical vapor deposition,where hydrogen and NaBH_(4) are respectively used as the carrier gas and the boron *** lattice structure of the as-synthesized borophene well coincides with the predictedα′-boron *** borophene-based photodetector shows an excellent broadband photoresponse from the ultraviolet(255 nm)to the infrared(940 nm)wavelengths,with enhanced responsivity compared to pristine borophene or graphene *** work informs emerging efforts to integrate borophene into nanoelectronic applications for both fundamental investigations and technological applications.

关键词： borophene graphene heterostructure photodetector two-dimensional materials

Inversion of Seabed Geotechnical Properties in the Arctic Chukchi Deep Sea Basin Based on Time Domain Adaptive Search Matching Algorithm

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Journal of Ocean University of China 2024年第4期23卷 933-942页

作者： AN Long XU Chong XING Junhui GONG wei JIANG Xiaodian XU Haowei LIU chuang YANG Boxue Jiangsu Automation Research Institute Lianyungang 222061China Key Laboratory of Submarine Geosciences and Prospecting Techniques MOE and College of Marine GeosciencesOcean University of ChinaQingdao 266100China Laboratory for Marine Mineral Resources Qingdao Marine Science and Technology CenterQingdao 266071China

The chirp sub-bottom profiler,for its high resolution,easy accessibility and cost-effectiveness,has been widely used in acoustic *** this paper,the acoustic impedance and grain size compositions were obtained based on the chirp sub-bottom profiler data collected in the Chukchi Plateau area during the 11th Arctic Expedition of *** time-domain adaptive search matching algorithm was used and validated on our established theoretical *** misfit between the inversion result and the theoretical model is less than 0.067%.The grain size was calculated according to the empirical relationship between the acoustic impedance and the grain size of the *** average acoustic impedance of sub-seafloor strata is 2.5026×10^(6) kg(s m^(2))^(-1)and the average grain size(θvalue)of the seafloor surface sediment is 7.1498,indicating the predominant occurrence of very fine silt sediment in the study *** of the inversion results and the laboratory measurements of nearby borehole samples shows that they are in general agreement.

关键词： time domain adaptive search matching algorithm acoustic impedance inversion sedimentary grain size Arctic Ocean Chukchi Deep Sea Basin

T-tube bridging fistula jejunal anastomosis for treatment of pancreatic lumbar dorsal fistula after necrotizing pancreatitis

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Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 428-430页

作者： Su-Lai Liu Guo-Guang Li wei Cheng chuang Peng Ying-Hui Song Department of Hepatobiliary Surgery Hunan Provincial People’s Hospital/The First Affiliated Hospital of Hunan Normal UniversityChangsha 410000China

Infectious pancreatic necrosis causes external pancreatic fistula in some ***,external pancreatic fistula requires fistula-gastric and/or intestinal anastomosis,and digestive endoscopic interventional treatment[1–3].It is especially difficult to treat external pancreatic fistulas with small fistulas where the external fistula is located in the lower *** common treatment is to remove the body and tail of the pancreas and the *** operation is very traumatic.A new pancreatic fistula may still occur at the pancreatic *** above operations may lead to unnecessary resection of the spleen,colon injury and other *** order to solve this problem,we innovatively used T-tube bridging fistula jejunal anastomosis plus continuous negative pressure suction to treat three cases of external pancreatic fistulas in the lower back,and all of them achieved good results.

关键词： fistula anastomosis spleen