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Prediction of contact resistance of electrical contact wear using different machine learning algorithms

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Friction 2024年第6期12卷 1250-1271页

作者： Zhen-bing CAI Chun-lin li Lei you xu-dong chen li-ping HE Zhong-qing CAO Zhi-nan ZHANG Tribology Research Institute Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China

H62 brass material is one of the important materials in the process of electrical energy transmission and signal transmission,and has excellent performance in all *** the wear behavior of electrical contact pairs is particularly complex when they are in service,we evaluated the effects of load,sliding velocity,displacement amplitude,current intensity,and surface roughness on the changes in contact *** learning(ML)algorithms were used to predict the electrical contact performance of different factors after wear to determine the correlation between different factors and contact *** forest(RF),support vector regression(SVR)and BP neural network(BPNN)algorithms were used to establish RF,SVR and BPNN models,respectively,and the experimental data were trained and *** was proved that BP neural network model could better predict the stable mean resistance of H62 brass alloy after *** analysis shows that the load and current have great influence on the predicted electrical contact *** wear behavior of electrical contacts is influenced by factors such as load,sliding speed,displacement amplitude,current intensity,and surface roughness during *** learning algorithms can predict the electrical contact performance after wear caused by these *** results indicate that an increase in load,current,and surface roughness leads to a decrease in stable mean resistance,while an increase in displacement amplitude and frequency results in an increase in stable mean resistance,leading to a decline in electrical contact *** reduce testing time and costs and quickly obtain the electrical contact performance of H62 brass alloy after wear caused by different factors,three algorithms(random forest(RF),support vector regression(SVR),and BP neural network(BPNN))were used to train and test experimental results,resulting in a machine learning model suitable for predicting the stable mean

关键词： electrical contact wear contact resistance machine learning(ML) neural network

Quantum Neural Network for Quantum Neural Computing

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Research 2024年第1期2023卷 71-80页

作者： Min-Gang Zhou Zhi-ping liu hua-Lei Yin chen-Long li Tong-Kai xu Zeng-Bing chen National Laboratory of Solid State Microstructures School of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China MatricTime Digital Technology Co.Ltd. Nanjing 211899China

Neural networks have achieved impressive breakthroughs in both industry and *** to effectively develop neural networks on quantum computing devices is a challenging open ***,we propose a new quantum neural network model for quantum neural computing using(classically controlled)single-qubit operations and measurements on real-world quantum systems with naturally occurring environment-induced decoherence,which greatly reduces the difficulties of physical *** model circumvents the problem that the state-space size grows exponentially with the number of neurons,thereby greatly reducing memory requirements and allowing for fast optimization with traditional optimization *** benchmark our model for handwritten digit recognition and other nonlinear classification *** results show that our model has an amazing nonlinear classification ability and robustness to ***,our model allows quantum computing to be applied in a wider context and inspires the earlier development of a quantum neural computer than standard quantum computers.

关键词： quantum thereby breakthrough

Neutron irradiation influence on high-power thyristor device under fusion environment

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Nuclear Science and Techniques 2024年第4期35卷 65-81页

作者： Wei Tong hua li Meng xu Zhi-Quan Song Bo chen School of Electrical Engineering and Automation Hefei University of TechnologyHefei 230009China Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China

Because of their economy and applicability,high-power thyristor devices are widely used in the power supply systems for large fusion *** high-dose neutrons produced by deuterium–tritium(D–T)fusion reactions are irradiated on a thyristor device for a long time,the electrical characteristics of the device change,which may eventually cause irreversible *** this study,with the thyristor switch of the commutation circuit in the quench protection system(QPS)of a fusion device as the study object,the relationship between the internal physical structure and external electrical parameters of the irradiated thyristor is ***,a series of targeted thyristor physical simulations and neutron irradiation experiments are conducted to verify the accuracy of the theoretical *** addition,the effect of irradiated thyristor electrical characteristic changes on the entire QPS is studied by accurate simulation,providing valuable guidelines for the maintenance and renovation of the QPS.

关键词： Fusion device Neutron irradiation effects Thyristor Quench protection

Numerical investigation on thermomechanical behavior of alumina–calcium hexaluminate refractories for purging plug

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Journal of Iron and Steel Research International 2024年第2期31卷 389-400页

作者： li-ping Pan Ya-wei li Fang-guan Tan Yi-chen chen Yang-fan xu Zhu He Bao-kuan li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430081HubeiChina National-Provincial Joint Engineering Research Center of High Temperature Materials and lining Technology Wuhan University of Science and TechnologyWuhan430081HubeiChina

Alumina–spinel refractories used in slit-type purging plugs are susceptible to cross-sectional damage,resulting in a serious mismatch between their service life and that of ***–calcium hexaluminate refractories have gradually become the new trend in purging plug materials with the development of refining *** thermomechanical damage of slit-type purging plugs with alumina–calcium hexaluminate refractory was investigated by the thermo-solid coupling *** with the polynomial fitting and design of experiments methods,the influence of thermophysical parameters on temperature and thermal stress of alumina–calcium hexaluminate refractories for purging plugs was systematically *** results show that the maximum thermal stress of the purging plugs appears during the stages of steel transporting and stirring,and the vulnerable parts are located above Y=0.323 *** thermal conductivity and the coefficient of thermal expansion of the material are the most sensitive parameters to the temperature and thermal stress inside the structure,*** addition of more calcium hexaluminate can relieve the stress concentration and large deformation around the ***,when the content of calcium hexaluminate is 47 wt.%and in the form of aggregate-binder,the temperature and thermal stress distribution inside the refractory are optimal,which can effectively improve the service life of the slit-type purging plug.

关键词： Purging plug Thermomechanical damage Refractory Design of experiments method Stress

Clinically significant changes in anal sphincter hiatal area in patients with gestational diabetes mellitus and pelvic organ prolapse

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World Journal of Diabetes 2024年第8期15卷 1726-1733页

作者： Qing-Hong Wang li-hua liu hua Ying ming-xu chen Chang-Jiang Zhou Hui li Department of Sonography People's Hospital Affiliated to Shandong First Medical UniversityJinan 271100Shandong ProvinceChina Department of Obstetrics and Gynecology People's Hospital Affiliated to Shandong First Medical UniversityJinan 271100Shandong ProvinceChina

BACKGROUND The prevalence of pelvic organ prolapse(POP)increases with age and ***,the prevalence of POP among women aged 20 to 39 is 9.7%,while it rises to 49%among women over 80 years ***,as the number of deliveries increases,the prevalence of POP also rises accordingly,with a rate of 12.8%for women with one delivery history,18.7%for those with two deliveries,and 24.6%for women with three or more *** causes immense suffering for pregnant *** To evaluate the relationship between the levator ani muscle’s hiatus(LH)area and POP in patients with gestational diabetes mellitus(GDM)using perineal *** The study cohort comprised 104 patients aged 29.8±3.7 years who sought medical care at our institution between January 2021 and June *** were singleton pregnancies consisting of 75 primiparas and 29 multiparas,with an average parity of 1.7±*** to the POP diagnostic criteria,the 104 subjects were divided into two groups with 52 members each:POP group(patients with GDM combined with POP)and non-POP group(patients with GDM without POP).Perineal ultrasound was used to measure differences in the anteroposterior diameter,transverse diameter,and LH *** operating characteristic curves were drawn to determine the optimal cutoff values for the LH anteroposterior diameter,transverse diameter,and area for diagnosing *** Statistically significant increase in the LH area,anteroposterior diameter,and lateral diameter were observed in the POP group compared with the non-POP group(P<0.05).Both groups exhibited markedly elevated incidence rates of macrosomia and stress urinary *** the POP group,the area under the curve(AUC)for the LH area was 0.906 with a 95%confidence interval(CI):*** optimal cutoff was 13.54cm²,demonstrating a sensitivity of 83.2%and a specificity of 64.4%.The AUC for the anteroposterior diameter reached 0.836 with a 95%CI:*** optimal cutoff was 5

关键词： Ultrasound Levator ani muscle hiatus Gestational diabetes mellitus Pelvic organ prolapse

Species recognition and the divergences in the chemical and ultrasonic signals between two coexisting Rattus species

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Current Zoology 2024年第4期70卷 531-538页

作者： Wei-Chao Wang Zhi-ming li Yi chen Jin-hua Zhang Jian-xu Zhang Yao-hua Zhang The State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijing 100101China CAs Center for Excellence in Biotic Interactions University of Chinese Academy of SciencesBeijingChina

The ability to recognize and differentiate between conspecifics and heterospecifics as well as their signals is critical for the coexistence of closely related *** the genus Rattus,species are morphologically similar and multiple species often ***,we investigated the interspecific recognition and signal differentiation of two sympatric rat species,the brown rat(Rattus norvegicus,RN)and the Asian house rat(Rattus tanezumi,RT).In a two-way choice test,both RN and RT females showed a preference for conspecific male rats to heterospecific *** females showed a significant preference for accessible urine of males of same species to those of other species,but not for the inaccessi-ble *** the other hand,there were significant differences in the structural characteristics of the ultrasonic vocalization emitted by males of these two rat *** dodecyl sulphate-polyacrylamide gel electrophoresis(SDS-PAGE)and isoelectric focusing electrophoresis unveiled that major urinary proteins(MUPs)in voided urine were more highly expressed in RN males versus RT *** interspecific dif-ferences of urinary volatile compounds were also *** conclusion,female rats had the ability to distinguish between males of either species.

关键词： Asian house rats brown rats closely related species pheromones ultrasonic vocalization.

Design of dual-functional protic porous ionic liquids for boosting selective extractive desulfurization

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Petroleum Science 2024年第4期21卷 2817-2829页

作者： Jin-Rui Zhang Jie Yin Jing He Hong-Shun Ran Wei Jiang Hong-ping li Wen-Shuai Zhu hua-ming li ming Zhang School of the Environment and Safety Engineering & Institute for Energy Research Jiangsu University School of Chemistry and Chemical Engineering Jiangsu University

Porous ionic liquids have demonstrated excellent performance in the field of separation, attributed to their high specific surface area and efficient mass transfer. Herein, task-specific protic porous ionic liquids(PPILs) were prepared by employing a novel one-step coupling neutralization reaction strategy for extractive desulfurization. The single-extraction efficiency of PPILs reached 75.0% for ***, adding aromatic hydrocarbon interferents resulted in a slight decrease in the extraction efficiency of PPILs(from 45.2% to 37.3%, 37.9%, and 33.5%), indicating the excellent extraction selectivity of PPILs. The experimental measurements and density functional theory calculations reveal that the surface channels of porous structures can selectively capture dibenzothiophene by the stronger electrophilicity(Eint(HS surface channel/DBT)=-39.8 kcal mol-1), and the multiple extraction sites of ion pairs can effectively enrich and transport dibenzothiophene from the oil phase into PPILs through π...π, C-H...π and hydrogen bonds interactions. Furthermore, this straightforward synthetic strategy can be employed in preparing porous liquids, offering new possibilities for synthesizing PPILs with tailored functionalities.

关键词： Protic porous ionic liquids Extractive desulfurization Selectivity Density functional theory

Ultrahigh thermoelectric properties of p‐type Bi_(x)Sb_(2−x)Te_(3)thin films with exceptional flexibility for wearable energy harvesting

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Carbon Energy 2024年第8期6卷 273-284页

作者： Zhuang‐Hao Zheng Yi‐ming Zhong Yi‐liu li Mohammad Nisar Adil Mansoor Fu li Shuo chen Guang‐Xing liang ping Fan Dongyan xu Meng Wei Yue‐Xing chen Shenzhen Key Laboratory of Advanced Thin Films and Applications Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhenChina Department of Mechanical and Automation Engineering The Chinese University of Hong KongSha TinChina

Use of a flexible thermoelectric source is a feasible approach to realizing selfpowered wearable electronics and the Internet of *** thin films are promising candidates for fabricating flexible power supply,but obtaining highthermoelectric‐performance thin films remains a big *** the present work,a p‐type Bi_(x)Sb_(2−x)Te_(3)thin film is designed with a high figure of merit of 1.11 at 393 K and exceptional flexibility(less than 5%increase in resistance after 1000 cycles of bending at a radius of∼5 mm).The favorable comprehensive performance of the Bi_(x)Sb_(2−x)Te_(3)flexible thin film is due to its excellent crystallinity,optimized carrier concentration,and low elastic modulus,which have been verified by experiments and theoretical ***,a flexible device is fabricated using the prepared p‐type Bi_(x)Sb_(2−x)Te_(3)and n‐type Ag_(2)Se thin ***,an outstanding power density of∼1028μWcm^(−2)is achieved at a temperature difference of 25 *** work extends a novel concept to the fabrication of highperformance flexible thin films and devices for wearable energy harvesting.

关键词： Bi_(x)Sb_(2−x)Te_(3) electrical transport properties flexibility thermoelectric

Structural engineering of hard carbon through spark plasma sintering for enhanced sodium-ion storage

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Rare Metals 2024年第9期43卷 4274-4285页

作者： Hao-ming Xiao Heng Zheng ping Yuan Jun-Hui Luo lin-lin Shen Jie-Feng Tan Xian-you Luo De li Yong chen Guangdong Key Laboratory for Hydrogen Energy Technologies School of Materials Science and Hydrogen EnergyFoshan UniversityFoshan 528000China State Key Laboratory of Marine Resource Utilization in South China Sea Hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti ResourcesHainan UniversityHaikou 570228China

Hard carbon(HC)has emerged as one of the superior anode materials for sodium-ion batteries(SIBs),with its electrochemical performance significantly influenced by the presence of oxygen functional groups and its closed pore ***,current research on the structural adjustment of these oxygen functional groups and the closed pore architecture within HC remains ***,energy-efficient and contamination-free spark plasma sintering technology was employed to tune the structure of coconut-shell HC,resulting in significant adjustments to the content of carboxyl(decreasing from 5.71 at%to 2.12 at%)and hydroxyl groups(decreasing from 7.73 at%to 6.26 at%).Crucially,these modifications reduced the irreversible reaction of oxygen functional groups with Na^(+).Simultaneously,a substantial number of closed pores with an average diameter of 1.22 nm were generated within the HC,offering an ideal environment for efficient Na^(+)*** structural changes resulted in a remarkable improvement in the electrochemical performance of the modified *** reversible specific capacity of the modified HC surged from 73.89 mAh·g^(-1)to an impressive 251.97 m Ah·g^(-1)at a current density of 50 mA·g^(-1).Even at 400 mA·g^(-1),the reversible specific capacity increased significantly from 14.55 to 85.44 mAh·g^(-1).Hence,this study provides a novel perspective for designing tailored HC materials with the potential to develop high-performance SIBs.

关键词： Hard carbon Spark plasma sintering Sodiumion batteries Closed pores Oxygen functional groups