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Wellbore-heat-transfer-model-based optimization and control for cooling downhole drilling fluid

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Petroleum Science 2024年第3期21卷 1955-1968页

作者： chao Wang He Liu Guo-Wei yu Chen yu Xian-Ming Liu Peng Huang Yangtze University Jingzhou434023HubeiChina State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China CNPC Bohai Drilling Engineering Co. LtdTianjin300280China Exploration Development and Construction Engineering Division of PetroChina Jidong Oilfield Company Tangshan63200HebeiChin Henan University of Urban Construction Pingdingshan467036HenanChina

To address the two critical issues of evaluating the necessity of implementing cooling techniques and achieving real-time temperature control of drilling fluids underground in the current drilling fluid cooling technology,we first established a temperature and pressure coupled downhole heat transfer model,which can be used in both water-based and oil-based drilling ***,fourteen factors,which could affect wellbore temperature,were *** on the standard deviation of the downhole temperature corresponding to each influencing factor,the influence of each factor was *** influencing factors that can be used to guide the drilling fluid's cooling technology were drilling fluid thermal conductivity,drilling fluid heat capacity,drilling fluid density,drill strings rotation speed,pump rate,viscosity,ROP,and injection *** nondominated sorting genetic algorithm was used to optimize these six parameters,but the optimization process took 182 *** these eight parameters'influence rules with the nondominated sorting genetic algorithm can reduce the optimization time to 108 ***,the downhole temperature has been demonstrated to increase with the inlet temperature increasing linearly under quasi-steady *** this law and PID,the downhole temperature can be controlled,which can reduce the energy for cooling the surface drilling fluid and can ensure the downhole temperature reaches the set value as soon as possible.

关键词： Drilling Cooling Influencing factors Analysis Optimization Control

Transferable adversarial slow feature extraction network for few-shot quality prediction in coal-to-ethylene glycol process

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Chinese Journal of Chemical Engineering 2024年第7期71卷 258-271页

作者： Cheng Yang chao Jiang Guo yu Jun Li Cuimei Bo School of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816China Department of Intelligent Manufacturing Nanjing Tech UniversityNanjing 210009China

In the coal-to-ethylene glycol(CTEG)process,precisely estimating quality variables is crucial for process monitoring,optimization,and control.A significant challenge in this regard is relying on offline laboratory analysis to obtain these variables,which often incurs substantial monetary costs and significant time *** resulting few-shot learning scenarios present a hurdle to the efficient development of predictive *** address this issue,our study introduces the transferable adversarial slow feature extraction network(TASF-Net),an innovative approach designed specifically for few-shot quality prediction in the CTEG ***-Net uniquely integrates the slowness principle with a deep Bayesian framework,effectively capturing the nonlinear and inertial characteristics of the CTEG ***,the model employs a variable attention mechanism to identify quality-related input variables adaptively at each time step.A key strength of TASF-Net lies in its ability to navigate the complex measurement noise,outliers,and system interference typical in CTEG *** learning strategy using a min-max game is adopted to improve its robustness and ability to model irregular industrial data accurately and ***,an incremental refining transfer learning framework is designed to further improve few-shot prediction performance achieved by transferring knowledge from the pretrained model on the source domain to the target *** effectiveness and superiority of TASF-Net have been empirically validated using a real-world CTEG *** with some state-of-the-art methods,TASF-Net demonstrates exceptional capability in addressing the intricate challenges for few-shot quality prediction in the CTEG process.

关键词： Chemical process Neural networks Slowness principle Transfer learning Prediction

Consistent and Accurate TDOA Localization in Dynamic NLOS Environments via Prior Information Independent Estimation

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CHINA COMMUNICATIONS 2024年第9期21卷 198-210页

作者： Luo, Mei Long, yu Xiong, Youzhi qin, Shuang Sichuan Normal Univ Coll Phys & Elect Engn Key Lab Wireless Sensor Network Univ Sichuan Prov Chengdu 610101 Peoples R China

In the time-difference-of-arrival (TDOA) localization, robust least squares (LS) problems solved by mathematical programming were proven to be superior in mitigating the effects of non-line-of-sight (NLOS) propagation. However, the existing algorithms still suffer from two disadvantages: 1) The algorithms strongly depend on prior information; 2) The approaches do not satisfy the mean square error (MSE) optimal criterion of the measurement noise. To tackle the troubles, we first formulate an MSE minimization model for measurement noise by taking the source and the NLOS biases as variables. To obtain stable solutions, we introduce a penalty function to avoid abnormal estimates. We further tackle the nonconvex locating problem with semidefinite relaxation techniques. Finally, we incorporate mixed constraints and variable information to improve the estimation accuracy. Simulations and experiments show that the proposed method achieves consistent performance and good accuracy in dynamic NLOS environments.

关键词： mathematical programming NLOS mitigation robust least squares TDOA MITIGATION

Weak interaction-steered evolution of polyoxovanadate-based metal-organic polyhedra from transformation via interlock to packing

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Chinese Chemical Letters 2024年第2期35卷 527-533页

作者： Yan-Hu Wang Ke-Wei Tong chao-qin Chen Jing Du Peng Yang College of Chemistry and Chemical Engineering Advanced Catalytic Engineering Research Center of the Ministry of EducationHunan UniversityChangsha 410082China College of Chemistry and Materials Science Testing and Analysis CenterHebei Normal UniversityShijiazhuang 050024China

A bottleneck in biomimetic synthesis consists in the full copy of,for example,the hierarchical structure of proteins directed by weak *** contrast with covalent bonds bearing definite orientation and high stability,weak intermolecular forces within a continuous dynamic equilibrium can be hardly tamed for molecular *** this endeavor,a ligand-dominated strategy that embodies tunable electrostatic repulsion andπ···πstacking was first employed to shape polyoxovanadate-based metal-organic polyhedra(VMOPs).Structural evolution involving transformation,interlock,and discovery of an unprecedented prototype of the Star of David was hence *** only as a handy tool for the primary structural control over VMOPs,these weak forces allow for an advanced management on the spatial distribution of such manmade macromolecules as well as the associated physicochemical behaviors,representing an ideal model for simulating and interpreting the conformation-function relationship of proteins.

关键词： Polyoxometalates Polyoxovanadates Metal-organic polyhedron Interlock Weak intermolecular forces

Heterogeneous MXene-based films with graded electrical conductivity towards highly efficient EMI shielding and electrothermal heating

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Nano Research 2024年第8期17卷 7264-7274页

作者： yu Zhang Guangcheng Zhang Zhonglei Ma Jianbin qin Xi Shen Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Research Institute for Sports Science and Technology The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

The increasing need for electromagnetic interference(EMI)shielding of electronics in cold environments such as those in aircraft,space exploration,and wearable heaters to avoid hazardous icing conditions or hypothermia requires the development of thin and lightweight EMI shielding materials preferably by absorbing rather than reflecting electromagnetic(EM)waves while also generating heat through energy-efficient electrothermal ***,it is challenging to achieve absorption-dominant EMI shielding and energy-efficient electrothermal heating simultaneously in a thin and lightweight ***,we develop a heterogeneous composite film comprising a porous multi-walled carbon nanotubes(MWCNTs)/bacterial cellulose(BC)film and an aligned MXene/Ag nanowires(NWs)backing via a sequential vacuum filtration *** porous film contains random conductive networks of MWCNTs with moderate conductivity while the aligned MXene sheets atop Ag NWs network affords high conductivity in the backing,giving rise to graded electrical conductivity for absorption-dominant EMI *** increasing Ag NW coverage leads to significantly increased electrical conductivity without increasing the EM wave reflection as well as the density and thickness of the film,yielding excellent specific EMI shielding effectiveness(>8500 dB/(g·cm^(2))),low driving voltage for energy-efficient electrothermal heating(163℃at 2.5 V),and fast response time(60 s)at a low areal density of 0.015 mg/cm^(2).Combining EMI shielding and electrothermal heating,the heterogeneous film developed here are promising contenders for the protection of electronic equipment in low-temperature environment.

关键词： heterogenous composite film MXene electromagnetic interference(EMI)shielding thermal management

Understanding Discrepancy of Power System Dynamic Security Assessment with Unknown Faults: A Reliable Transfer Learning-based Method

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 427-431页

作者： chao Ren Han yu Yan Xu Zhao Yang Dong School of Computer Science and Engineering Nanyang Technological UniversitySingapore School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore

This letter proposes a reliable transfer learning(RTL)method for pre-fault dynamic security assessment(DSA)in power systems to improve DSA performance in the presence of potentially related unknown *** takes individual discrepancies into consideration and can handle unknown faults with incomplete *** experiment results demonstrate high DSA accuracy and computational efficiency of the proposed RTL *** analysis shows RTL can guarantee system performance.

关键词： Adversarial training dynamic security assessment maximum classifier discrepancy missing data transfer learning

Metallographic investigationof first full-sizehigh-Jc Nb_(3)Sn cable-in-conduit conductor aftercyclicloadingtests

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Superconductivity 2024年第1期9卷 1-8页

作者： chao Dai yunhao Liu Zichuan Guo yu Wu Arend Nijhuis Tianjun Xue Zuojiafeng Wu Jinggang qin Huainan New Energy Research Center Huainan 232000People’s Republic of China University of Twente EnergyMaterials and SystemsFaculty of Science and TechnologyEnschede 7500AENetherlands University of Science and Technology of China Hefei 230026People’s Republic of China Baiyin Non-ferrous Changtong Wire&Cable Co.Ltd BaiyinGansu 730900People’s Republic of China Longteng Mechanical and Electrical Co. LtdYiChun 336000People’s Republic of China

In order to verify the feasibility of applying high-Jc Nb_(3)Sn strand in fusion magnet,a full-size cable-in-conduit conductor(CICC)with short twist pitch(STP)cable pattern was manufactured and tested in SULTAN facility at SPC,*** levels of cyclic electromagnetic(EM)load were applied on the sample stepwise,no visible decrease of current sharing temperature(TcsT was observed until the EM load increased to 80 kA×10.8 T,after that the Tcs decreased dramatically with the EM cycles,which suggested that irreversible deformation,causing a change in the strain state,or even damage has occurred in the superconducting *** investigating the reason which caused the conductor performance degradation,the tested conductor was dissected for metallographic *** segments which subjected to different EM loads were extracted from one of the legs,the geometric feature changes of the cable cross-sections were analyzed and compared.A good correlation was found between the decrease of the Tcs and deformation of the cable cross section.A mass of cracks were found on the sub-elements of strands in the segment which subjected to highest EM load,but the amount of crack is much lower in other *** the analyses,it is speculated that the critical EM load which causes irreversible degradation is between 850 kN/m and 870 kN/m for this *** results could be a reference in high-Jc Nb_(3)Sn CICC design.

关键词： High‐Jc Nb_(3)Sn Cable‐in‐conduit conductor Metallography

Universal and efficient hybrid modeling and direct slicing method for additive manufacturing processes

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Advances in Manufacturing 2024年第2期12卷 300-316页

作者： Sen-Lin Wang Li-chao Zhang chao Cai Ming-Kai Tang Si Chen Jiang Huang yu-Sheng Shi State Key Laboratory of Materials Processing and Die and Mould Technology Huazhong University of Science and TechnologyWuhan430074People’s Republic of China School of Machinery and Automation Wuhan University of Science and TechnologyWuhan430081People’s Republic of China

Model design and slicing contour generation in additive manufacturing(AM)data processing face challenges in terms of efficiency and scalability when stereolithography files generated by complex functionally graded structures have millions of *** paper proposes a hybrid modeling and direct slicing method for AM to efficiently construct and handle complex three-dimensional(3D)*** 3D solids,including conformal multigradient structures,were uniformly described using a small amount of data via signed distance *** hybrid representations were quickly discretized into numerous disordered directed lines using an improved marching squares *** establishing a directional HashMap to construct the topological relationship between lines,a connecting algorithm with linear time complexity is proposed to generate slicing contours for *** method replaces the mesh reconstruction and Boolean operation stages and can efficiently construct complex conformal gradient models of arbitrary topologies through hybrid ***,the time and memory consumption of direct slicing are much lower than those of previous methods when handling hybrid models with hundreds of millions of faces after mesh reconstruction.

关键词： Additive manufacturing(AM) Hybrid modeling Direct slicing Signed distance field

Numerical simulation of formaldehyde distribution characteristics in the high-speed train cabin

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Building Simulation 2024年第2期17卷 285-300页

作者： Fan Wu Hang Dong chao yu Hengkui Li qingmin Cui Renze Xu Key Laboratory of Traffic Safety on Track Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangshaHunan410075China Joint International Research Laboratory of Key Technologies for Rail Traffic Safety ChangshaHunan410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle ChangshaHunan410075China School of Software Henan University of EngineeringZhengzhouHenan451191China

The global concern over indoor air pollution in public vehicles has grown *** a focus on enhancing passengers’comfort and health,this study endeavors to investigate the distribution characteristics of formaldehyde within a high-speed train cabin by employing a computational fluid dynamics(CFD)model which is experimentally validated in a real cabin *** research focuses on analyzing the impact of air supply modes,temperature,relative humidity,and fresh air change rate on the distribution and concentration of *** results demonstrate that the difference in average formaldehyde concentration between the two air supply modes is below 1.3%,but the top air supply mode leads to a higher accumulation of formaldehyde near the sidewalls,while the bottom air supply mode promotes a more uniform distribution of ***,the temperature,relative humidity,and fresh air change rate are the primary factors affecting formaldehyde concentration levels,but they have modest effects on formaldehyde’s distribution pattern within the *** the temperature and relative humidity increase,the changes in formaldehyde concentrations in response to variations in these factors become more ***,the formaldehyde concentration may surpass the standard limit of 0.10 mg/m^(3)if the fresh air change rate falls below 212 m^(3)/*** research provides a systematic approach and referenceable results for exploring formaldehyde pollution in high-speed train cabins.

关键词： indoor air pollution formaldehyde CFD simulation high-speed train ventilation