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Effect of tungsten carbide particles on microstructure and mechanical properties of Cu alloy composite bit matrix

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Journal of Iron and Steel Research(International) 2024年第2期31卷 519-530页

作者： Ding-qian Dong Feng-yuan He Xin-hui chen hui Li Kai-hua Shi hui-wen xiong Xin Xiang Li Zhang College of Mechanical Engineering Sichuan University of Science and EngineeringZigong643000SichuanChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083HunanChina Zigong Cemented Carbide Co. Ltd.Zigong643011SichuanChina Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Science and EngineeringZigong643000SichuanChina

Copper alloy composite bit matrix was prepared by pressureless vacuum infiltration,using at least one of the three kinds of tungsten carbide particles,for example,irregular cast tungsten carbide,monocrystalline tungsten carbide and sintered reduced tungsten carbide particles.The effects of powder particle morphology,particle size and mass fraction of tungsten carbide on the microstructure and mechanical properties of copper alloy composite were investigated by means of scanning electron microscopy,X-ray diffraction and abrasive wear test in detail.The results show that tungsten carbide morphology and particle size have obvious effects on the mechanical properties of copper alloy composites.Cast tungsten carbide partially dissolved in the copper alloy binding phase,and layers of Cu_(0.3)W_(0.5)Ni_(0.1)Mn_(0.1)C phase with a thickness of around 8–15μm were formed on the edge of the cast tungsten carbide.When 45%irregular crushed fine cast tungsten carbide and 15%monocrystalline cast tungsten carbide were used as the skeleton,satisfactory comprehensive performance of the reinforced copper alloy composite bit matrix was obtained,with the bending strength,impact toughness and hardness reaching 1048 MPa,4.95 J/cm^(2) and 43.6 HRC,respectively.The main wear mechanism was that the tungsten carbide particles firstly protruded from the friction surface after the copper alloy matrix was worn,and then peeled off from the matrix when further wear occurred.

关键词： Polycrystalline diamond compact Pressureless vacuum infiltration Copper alloy composite bit matrix Microstructure characterization Abrasive wear behavior

Theoretical understanding of correlation between magnetic phase transition and the superconducting dome in high-Tc cuprates

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 167-173页

作者： chen Zhang Cai-Xin Zhang Su-Huai Wei Haiqing Lin hui-xiong Deng State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Computational Science Research Center Beijing 100193China

Many issues concerning the origin of high-temperature superconductivity(HTS)are still under debate.For example,how the magnetic order varies with doping and its relationship with the superconducting temperature(Tc);and why Tcalways peaks near the quantum critical point.In this paper,taking hole-doped La_(2)CuO_(4)as a classical example,we employ the first-principles band structure and total energy calculations with Monte Carlo simulations to explore how the symmetry-breaking magnetic ground state evolves with hole doping and the origin of a dome-shaped superconductivity region in the phase diagram.We demonstrate that the local antiferromagnetic order and doping play key roles in determining the electron-phonon coupling,thus Tc.Initially,the La_(2)CuO_(4)possesses a checkerboard local antiferromagnetic ground state.As the hole doping increases,Tcincreases with the enhanced electron-phonon coupling strength.But as the doping increases further,the strength of the antiferromagnetic interaction weakens and spin fluctuation increases.At the critical doping level,a magnetic phase transition occurs that reduces the local antiferromagnetism-assisted electron-phonon coupling,thus diminishing the Tc.The superconductivity disappears in the heavily overdoped region when the ferromagnetic order dominates.These observations could account for why cuprates have a dome-shaped superconductivity region in the phase diagram.Our study,thus,contributes to a fundamental understanding of the correlation between doping,local magnetic order,and superconductivity of HTS.

关键词： high-temperature superconductivity antiferromagnetic order electron-phonon coupling doping effect cuprates

Respiratory Viruses and Mycoplasma Pneumoniae Surveillance Among Hospitalized Children with Acute Respiratory Infections—Wuhan City,Hubei Province,China,September-November 2023

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China CDC weekly 2024年第8期6卷 139-142页

作者： Ying Li Yi Yan Jiaming Huang Yue Shi hui Du Chao xiong Kai chen Di Liu Xiaoxia Lu Computational Virology Group Center for Bacteria and Viruses Resources and BioinformationWuhan Institute of VirologyChinese Academy of SciencesWuhan CityHubei ProvinceChina Department of Respiratory Medicine Wuhan Children’s HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan CityHubei ProvinceChina Pediatric Respiratory Disease Laboratory Institute of Maternal and Child HealthWuhan Children's HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan CityHubei ProvinceChina University of Chinese Academy of Sciences BeijingChina CAS Key Laboratory of Special Pathogens and Biosafety Wuhan Institute of VirologyCenter for Biosafety Mega-ScienceChinese Academy of SciencesWuhan CityHubei ProvinceChina Data Center Wuhan Children’s HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan CityHubei ProvinceChina

Summary What is already known about this topic?Acute respiratory infections(ARIs)are a significant contributor to illness and death in children.There has been a notable rise in the occurrence of ARIs and the associated pathogens in China,which has garnered worldwide attention.What is added by this report?This study conducted a retrospective analysis of the clinical characteristics of children with ARIs in Wuhan City from September to November 2023.

关键词： November Wuhan Hubei

Diagnostic values of questionnaires of Convergence Insufficiency Symptom Survey and College of Optometrists Vision Development Quality of Life in the screening of convergence insufficiency

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International Journal of Ophthalmology(English edition) 2024年第5期17卷 904-908页

作者： Ling xiong Qian chen Ye Wu Department of Ophthalmology West China HospitalSichuan University/Laboratory of Optometry and Vision ScienceWest China School of MedicineChengdu 610041Sichuan ProvinceChina Department of Clinical Research Management Center of BiostatisticsDesignMeasurement and EvaluationWest China HospitalSichuan UniversityChengdu 610041Sichuan ProvinceChina

AIM:To compare and analyse the diagnostic efficacy of the College of Optometrists Vision Development Quality of Life Questionnaire(COVD-QOL)and the Convergence Insufficiency Symptom Survey(CISS)in detecting convergence insufficiency and to compare their diagnostic value in clinical applications.METHODS:Using the diagnostic test method,62 adult patients with convergence insufficiency(age:24.74±3.75y)and 62 normal participants(age:23.61±3.13y)who visited the Optometry Clinic of West China Hospital of Sichuan University from April 2021 to January 2023 were included.All subjects completed the CISS and COVD-QOL.Statistical analysis of the sensitivity and specificity of the CISS and COVD-QOL and comparison and joint experimental analysis of their diagnostic efficacy were performed.RESULTS:The sensitivity of the CISS and COVD-QOL for convergence insufficiency was 64.5%and 71.0%,respectively,while the specificity was 96.8%and 67.7%,respectively.Compared to the CISS alone,the combination of the CISS and COVD-QOL demonstrated lower sensitivity and specificity.The areas under the receiver operating characteristic curve of CISS,COVD-QOL and CISS combined with COVD-QOL were 0.806,0.694 and 0.782,respectively.CONCLUSION:Considering the low sensitivity of the CISS and the low specificity of the COVD-QOL,it is recommended to supplement these questionnaires with other screening tests for the detection of convergence insufficiency.

关键词： convergence insufficiency symptom survey College of Optometrists Vision Development Quality of Life Questionnaire convergence insufficiency asthenopia

Gut microbiota affects the estrus return of sows by regulating the metabolism of sex steroid hormones

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Journal of Animal Science and Biotechnology 2024年第2期15卷 578-599页

作者： Min Liu Jia Zhang Yunyan Zhou Shuqi xiong Mengqing Zhou Lin Wu Qin Liu Zhe chen hui Jiang Jiawen Yang Yuxin Liu Yaxiang Wang Congying chen Lusheng Huang National Key Laboratory of Swine Genetic Improvement and Germplasm Innovation Jiangxi Agricultural UniversityNanchang 330045China

Background Sex hormones play important roles in the estrus return of post-weaning sows.Previous studies have demonstrated a complex and bi-directional regulation between sex hormones and gut microbiota.However,the extent to which the gut microbiota affects estrus return of post-weaning sows is largely unknown.Results In this study,we first screened 207 fecal samples from well-phenotyped sows by 16S rRNA gene sequencing and identified significant associations between microbes and estrus return of post-weaning sows.Using metagenomic sequencing data from 85 fecal samples,we identified 37 bacterial species that were significantly associated with estrus return.Normally returning sows were characterized by increased abundances of L.reuteri and P.copri and decreased abundances of B.fragilis,S.suis,and B.pseudolongum.The changes in gut microbial composition significantly altered the functional capacity of steroid hormone biosynthesis in the gut microbiome.The results were confirmed in a validation cohort.Significant changes in sex steroid hormones and related compounds were found between normal and non-return sows via metabolome analysis.An integrated analysis of differential bacterial species,metagenome,and fecal metabolome provided evidence that normal return-associated bacterial species L.reuteri and Prevotella spp.participated in the degradation of pregnenolone,progesterone,and testosterone,thereby promoting estrogen biosynthesis.Furthermore,the microbial metabolites related to sow energy and nutrient supply or metabolic disorders also showed relationships with sow estrus return.Conclusions An integrated analysis of differentially abundant bacterial species,metagenome,and fecal metabolome revealed the involvement of L.reuteri and Prevotella spp.in sow estrus return.These findings provide deep insight into the role of gut microbiota in the estrus return of post-weaning sows and the complex cross-talk between gut microbiota and sex hormones,suggesting that the manipulation of the gut microbiota could be an effective st

关键词： Estrus return Fecal metabolome Gut microbiota Metagenomics Sex steroid hormones Sow

Probing the interseismic locking state of the Xianshuihe fault based on a viscoelastic deformation model

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Science China Earth Sciences 2024年第1期67卷 134-145页

作者： Yage ZHU Faqi DIAO Fei chen Yuebing WANG Zhigang SHAO Rongjiang WANG xiong xiong Hubei Subsurface Multi-Scale Imaging Key Laboratory School of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China China Earthquake Networks Center Beijing 100045China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China

The interseismic locking state of tectonic faults is essential for regional seismic hazard assessments.However,it is challenging to obtain this parameter reliably due to the weak deformation and complex model configurations.To better probe the fault locking state,more reliable physical models and well-covered observations are required.Here we investigate the locking state of the Xianshuihe fault based on a new-developed viscoelastic deformation model.Meanwhile,we combine GPS velocities from 13 new near-field stations and existing stations in this region to improve the spatial resolution.Similar to the theoretical predictions,our results indicate that the elastic model will clearly overestimate the fault locking depth and seismic moment accumulation rate,and the fault slip rate inferred from the elastic model is slightly lower than that from the viscoelastic model.Relying on the locking distribution inferred from the viscoelastic model,we identify four potential asperities on the Xianshuihe fault.More importantly,we find a clear spatial correlation between the fault locking distribution and the rupture extent of historical earthquakes,which indicates that the fault locking state may control the rupture extent and thus the magnitude of earthquakes.In addition,our results show that the 2022 M6.8 Luding earthquake only ruptured the south part of a potential asperity,and the accumulated energy in the northern unruptured area is equivalent to an Mw6.9 earthquake,where the seismic hazard deserves special attention.

关键词： Fault kinematics Viscoelastic relaxation effect GPS observations Seismic hazard The 2022 M6.8 Luding earthquake

Adaptive composite anti-disturbance control for heavy haul trains

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Transportation Safety and Environment 2024年第1期6卷 75-82页

作者： Longsheng chen hui Yang School of Electrical and Automation Engineering East China Jiaotong UniversityNanchang 33013JiangxiChina School of Aircraft Engineering Nanchang Hangkong UniversityNanchang 330063JiangxiChina

In this paper,an adaptive composite anti-disturbance control of heavy haul trains(HHTs)is proposed.First,the mechanical principle and characteristics of couplers are analysed and the longitudinal multi-particles nonlinear dynamic model of HHTs is established,which can satisfy that the forces of vehicles in different positions are different.Subsequently,a radial basis function network(RBFNN)is employed to approximate the uncertainties of HHTs,and a nonlinear disturbance observer(NDO)is constructed to estimate the approximation error and external disturbances.To indicate and improve the approximation accuracy,a serial-parallel identification model of HHTs is constructed to generate a prediction error,and an adaptive composite anti-disturbance control scheme is developed,where the prediction error and tracking error are employed to update RBFNN weights and an auxiliary variable of NDO.Finally,the feasibility and effectiveness of the proposed control scheme are demonstrated through the Lyapunov theory and simulation experiments.

关键词： heavy haul train(HHT) radial basis function neural network nonlinear disturbance observer(NDO) serial-parallel identification model composite anti-disturbance control

B-cell lymphoma-2 phosphorylation at Ser70 site-related autophagy mediates puerarin-inhibited the apoptosis of MC3T3-E1 cells during osteoblastogenesis

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Journal of Traditional Chinese Medicine 2024年第1期44卷 27-34页

作者： LI Xi LIN Xiangquan chen Dongdong LIU hui the Third Clinical Medical College Fujian Medical University Department of Orthopedics Fuzhou Second HospitalFuzhou 350007China

OBJECTIVE:To explore the relationship between autophagy and apoptosis regulated by puerarin during osteoblastogenesis.METHODS:In this study,the effects of puerarin on the autophagic activity and apoptosis level of osteoblast precursors(MC3T3-E1 cells)was observed.Subsequently,the roles of puerarin on B-cell lymphoma-2(Bcl-2)phosphorylation at different sites in osteoblast precursors were observed.The effect of puerarin on the interaction between Bcl-2 and autophagy regulatory molecule or pro-apoptotic molecule was also investigated using Co-immunoprecipitation assays.In addition,the effect of puerarin on mitochondrial membrane potential of osteoblast precursors was also identified by mitochondrial membrane potential fluorescence probe assays.RESULTS:Our results showed that puerarin can promote the autophagic activity and apoptosis level of MC3T3-E1cells.In addition,puerarin promoted Bcl-2phosphorylation at Ser70 site,and the dissociation of Bcl-2-Beclin1 complex.Moreover,puerarin could enhance the binding of Bcl-2-Bcl-2-Associated X(Bax)complex in MC3T3-E1 cells.Furthermore,puerarin increased the mitochondrial membrane potential of MC3T3-E1 cells.CONCLUSIONS:Therefore,puerarin promotes Beclin1into autophagy flux through Bcl-2 phosphorylation at Ser70,thereby enhancing autophagy of osteoblast precursors,which mediates its anti-apoptotic role during osteoblastogenesis.Furthermore,the dissociation of Bcl-2-Beclin1 complex is conducive to the binding of Bcl-2-Bax complex,which resists the apoptosis of osteoblast precursors via the increased mitochondrial membrane potential.

关键词： puerarin osteoblasts autophagy apoptosis lymphoma B-cell

Understanding the mechanism underlying the anti-inflammatory effect of dietary flavonoids on IBD: a focus on gut microbiota and its metabolites involved in SCFA， bile acid， tryptophan and lipopolysaccharides

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Food Science and Human Wellness 2024年

作者： huihui xiong hui chen Lingli chen Kehui Ouyang Suyun Lin Wenjun Wang College of Food Science and Engineering Jiangxi Agricultural University College of Animal Science and Technology Jiangxi Agricultural University

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease with a high incidence. Treatment for IBD includes medications and diet， and common anti-inflammatory medications have limitations like drug resistance and serious adverse effects. Accumulating evidence has demonstrated that dietary flavonoids exhibit an alleviative effect on IBD by influencing gut microbiota. The microbiota-derived metabolites also regulate IBD and maintain intestinal homeostasis. In this review， we investigate the therapeutic effect of gut microbiota and metabolites on IBD by intestinal immune and intestinal barrier function. We demonstrate the underlying mechanism of dietary flavonoids as an anti-inflammatory molecule alleviating IBD by regulating gut microbiota， short chain fatty acid (SCFA)， bile acid (BA)， tryptophan (Trp) metabolism and lipopolysaccharides (LPS)-toll-like receptor 4 (TLR4) signaling pathway. Based on structural differences of flavonoids， we summarize the recent research progress on the role of different dietary flavonoids in alleviating IBD by gut microbiota and metabolites in animal and clinical trials. This review indicates that dietary flavonoids targeting gut microbiota and metabolites provide a promising strategy for the treatment of inflammation and novel insights into the management of IBD.

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