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Dynamic recrystallization behavior and strengthening mechanism of a novel Mo-Ti_(3)AlC_(2) alloy at ultrahigh temperature

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Rare Metals 2024年第8期43卷 3946-3960页

作者： Lu Yang Xin-Yuan Zheng Yang Zhao Xi-ran Wang Fang-Nao Xiao Shi-Zhong Wei School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials Henan University of Science and TechnologyLuoyang 471003China Department of Applied Mechanics Univ.Bourgogne FrancheComteFEMTO-ST InstituteCNRS/UF/ENSMM/UTBM25000BesangonFrance

Increasing the recrystallization temperature to achieve better high-temperature performance is critical in the development of molybdenum alloys for ultrahightemperature applications,such as the newest generation of multitype high-temperature nuclear *** this study,an innovative strategy was proposed to improve the performance of molybdenum alloys at high temperature by using the two-dimensional MAX(where M is an early transition metal,A is an A-group element and X is C or N)ceramic material Ti_(3)AlC_(2).The relationships between flow stress,strain rate and temperature were *** microstructure,distribution of misorientation and evolution of dislocations in the Mo-Ti_(3)AlC_(2) alloy were *** microscopic mechanism of the Ti_(3)AlC_(2) phase in the molybdenum alloy at high temperatures was *** experimental results showed that the peak flow stress of Mo-Ti_(3)AlC_(2) at 1600℃ reached 155 MPa,which was161.8% greater than that of pure *** activation energy of thermal deformation of Mo-Ti_(3)AlC_(2) was as large as537 kJ·mol~(-1),which was 17.6% more than that of pure *** recrystallization temperature reached 1600℃ or even *** topological reaction of the Ti_(3)AlC_(2) phase consumed a large amount of energy at high temperatures,resulting in increases in the deformation activation *** structures of AlTi_3 and Ti-O Magneli-phase oxides(Ti_nO_(2n-1)) were formed in-situ,which relied on kink bands and interlayer slip,resulting in many dislocations during ***,the special two-dimensional of the structure Ti_(3)AlC_(2) ceramic inhibited the recrystallization behavior of the Mo *** results of this study can provide theoretical guidance for the development of a new generation of molybdenum alloys for use in ultrahigh-temperature environments.

关键词： Mo alloy Two-dimensional reinforcement Dynamic recrystallization behavior Hot deformation Mechanical properties

Effects of anterior sciatic nerve acupuncture on lower limb paralysis after cerebral infarction:study protocol for a randomized controlled trial

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Journal of Traditional Chinese Medicine 2024年第1期44卷 205-211页

作者： LI Menghan WANG Yu ran Dawei YANG Xinming DENG Shizhe SHI Lei MENG Zhihong Department of Acupuncture First Teaching Hospital of Tianjin University of Traditional Chinese MedicineTianjin 300193China National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion Tianjin 300193China Graduate department Tianjin University of Traditional Chinese MedicineTianjin 301617China Department of Massage and Rehabilitation Second Affiliated Hospital of Tianjin University of Traditional Chinese MedicineTianjin 300250China

Stroke is the main cause of disability in the middle and old ***,especially lower limb paralysis,often leads to the loss of self-care ability and a series of secondary *** main method to improve hemiplegic limb movement is exercise therapy,but there are still many patients with disabilities after rehabilitation *** one of the non-pharmacological therapies for stroke,acupuncture has been recognized to improve motor function in ***,we propose a new method,anterior sciatic nerve acupuncture,which can stimulate both the femoral nerve and the sciatic *** designed this study to determine the effect of this method on lower limb motor *** participants recruited with hemiplegia after cerebral infarction will be randomly assigned to the test group or control group in a 1:1 *** control group will receive Xingnao Kaiqiao acupuncture,and the test group will receive anterior sciatic nerve acupuncture on this *** participants will get acupuncture treatment once a day,6 times a week for 2 *** primary outcome is Fugl-Meyer Assessment of Lower Extremity and the secondary outcomes are Modified Ashworth Scale and Modified Barthel *** will be collected before treatment,1week after treatment,and 2 weeks after treatment,and then statistical analysis will be *** study can preliminarily verify the effect of anterior sciatic nerve acupuncture on improving lower limb motor function in patients with cerebral infarction,which may provide an alternative approach for clinical treatment of hemiplegia.

关键词： anterior sciatic nerve acupuncture paralysis cerebral infarction Xingnao Kaiqiao clinical protocols

Numerical investigation on ball-sealers transport and diversion performance in shale gas horizontal well based on semi-resolved CFD-DEM

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Particuology 2024年第10期93卷 137-153页

作者： Yinjian Huang Jinzhou Zhao Lan Ren ran Lin Jianfa Wu Cheng Shen Jianjun Wu Bing Li National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China Tianfu Yongxing Laboratory Chengdu610213China Shale Gas Research Institute PetroChina Southwest Oil&Gasfield CompanyChengdu610056China PetroChina Coalbed Methane Company Limited Xi’an710082China

In the staged multi-cluster fracturing of shale gas horizontal wells, ball sealers are used to ensure uniform fluid distribution among clusters, a strategy that is both cost-effective and operationally beneficial. Despite these advantages, comprehending the ball sealers' dynamics within the wellbore and their plugging behavior at perforations is still challenging. This complexity results in prediction difficulties regarding their diversion efficiency. To address this, our study utilized a semi-resolved CFD-DEM model based on kernel approximation to simulate the behavior of medium-sized ball sealers in single and multiple cluster scenarios. Our findings from a single cluster scenario reveal that the plugging probability is co-determined by velocity gradients in the fluid ingestion area near the perforation, backflow region, and inertial forces of the ball sealers. As the critical flow rate is achieved, the plugging probability negatively correlated with fluid viscosity and displacement, and positively correlated with the perforation flow ratio (PFR), the difference in particle-fluid density, ball sealer’s diameter, and the ball sealer’s offset from the pipeline center. Temporary plugging control efficiency was used to evaluate the flow balance effect among multiple clusters. The results indicate that an increased number of ball sealers enhances the fault tolerance during the temporary plugging process. Nevertheless, excessive ball sealers might undermine the temporary plugging control efficiency, as perforations with lower fluid inflow rates are unexpectedly plugging. Higher differences in fluid injection rates between clusters led to increased efficiency in temporary plugging control. Premature deployment of ball sealers cannot effectively plug perforations with marginally higher fluid inflow rates, but instead accidently plug intermediate clusters with lower fluid inflow rates. These findings offer a theoretical basis for optimizing the design of ball sealers.

关键词： Gas shale Horizontal wells Ball sealer Semi-resolved CFD-DEM Diversion

A Class of m-Complex Symmetric Operators on Hardy Space

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Journal of Mathematical Research with Applications 2024年第1期44卷 63-80页

作者： Jia FU Xinmei LI ran LI School of Mathematics Liaoning Normal University

In this paper,we study the necessary and sufficient condition that the Toeplitz operators with respect to the conjugations of one permutation are 2-complex ***,we introduce a class of conjugations called the conjugations of one permutations on the classical Hardy ***,Toeplitz operators are completely characterized as 2-complex symmetric structure under this class of *** matrix representation of Toeplitz operators in the classical regular orthogonal basis on Hardy space is used to describe this class of 2-complex symmetric Toeplitz ***,we add two preconditions fn=-f-nand fn=f-nrespectively to the Toeplitz operators,and we get more simplified *** the second condition,we study the 3-complex symmetry of Toeplitz operators,and we get the same result for Tfis a 3-CSO with the conjugation C((i,j)) and 2-CSO’s.

关键词： m-complex symmetric operator Toeplitz operator Hardy space

Cutting performance of saw blades with microtextured rougher and finisher sawteeth

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Advances in Manufacturing 2024年第2期12卷 317-334页

作者： Yang Lu Jian-Xin Deng Zhi-Hui Zhang Jia-Xing Wu ran Wang Yi-Chen Bao Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE School of Mechanical EngineeringShandong UniversityJinan250061People’s Republic of China

The problems of severe sawtooth wear,harsh sawing noise,and low surface quality during the processing of circular saw blades need to be *** improve the cutting performance of TiC-based cermet saw blades,microtextures parallel to the cutting edge were fabricated on rough and fine sawteeth by laser *** cutting tests were performed on a sawing platform under lubricated *** of the sawing arc length and working sawtooth cutting force variations were developed for sawing steel pipes,and the accuracy of the sawing force model was verified *** results indicate that the variations in the sawing force are proportional to the sawing arc *** circular saw blades with microtextures that did not penetrate the sawtooth rake face exhibited the lowest cutting force,sawing noise,and highest machined surface ***,the worn-out distance of the rougher and finisher sawteeth was reduced by approximately 7.4%and 44.1%,respectively,compared with conventional circular saw *** main failure modes of sawteeth were tip wear,rake face adhesion,and oxidative *** addition,the mechanism by which the textures improve the cutting and wear properties of TiC-based circular saw blades was *** study provided a significant concept for enhancing the cutting performance of circular saw blades and improving the machined surface quality.

关键词： Circular saw blades Micro textures Cutting performance Wear performance

Sustainable all-weather CO2 utilization by mimicking natural photosynthesis in a single material

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National Science Review 2024年第2期11卷 177-187页

作者： Xianjin Shi Yu Huang ran Long Zhenyu Wang Liqin Wang Junji Cao Gangqiang Zhu Yujie Xiong State Key Laboratory of Loess and Quaternary Geology(SKLLQG) Key Laboratory of Aerosol Chemistry and Physics Institute of Earth EnvironmentChinese Academy of Sciences Center of Excellence in Quaternary Science and Global Change Chinese Academy of Sciences University of Chinese Academy of Sciences Hefei National Research Center for Physical Sciences at the Microscale School of Chemistry and Materials Science and National Synchrotron Radiation Laboratory University of Science and Technology of China Institute of Atmospheric Physics Chinese Academy of Sciences School of Physics and Information Technology Shaanxi Normal University

Solar-driven CO2conversion into hydrocarbon fuels is a sustainable approach to synchronously alleviating the energy crisis and achieving net ***,the dependence of the conversion process on solar illumination hinders its practical application due to the intermittent availability of sunlight at night and on cloudy or rainy ***,we report a model material of Pt-loaded hexagonal tungsten trioxide（Pt/h-WO3） for decoupling light and dark reaction processes,demonstrating the sustainable CO2conversion under dark conditions for the first *** such a material system,hydrogen atoms can be produced by photocatalytic water splitting under solar illumination,stored together with electrons in the h-WO3through the transition of W6+to W5+and spontaneously released to trigger catalytic CO2reduction under dark ***,we demonstrate using natural light that CH4production can persist at night and on rainy days,proving the accomplishment of all-weather CO2conversion via a sustainable way.

关键词： sustainable CO2 utilization artificial photosynthesis all-weather application charge storage

Dynamic response mechanism and precursor characteristics of gneiss rockburst under different initial burial depths

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Journal of Mountain Science 2024年第3期21卷 1004-1018页

作者： LIU Dongqiao SUN Jie MENG Wen HE Manchao ZHANG Chongyuan LI ran CAO Binghao State Key Laboratory for Tunnel Engineering China University of Mining and TechnologyBeijing 100083China Key Laboratory of Active Tectonics and Geological Safety Ministry of Natural ResourcesInstitute of GeomechanicsChinese Academy of Geological SciencesBeijing 100081China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China

To investigate the influence mechanism of geostress on rockburst characteristics,three groups of gneiss rockburst experiments were conducted under different initial geostress conditions.A high-speed photography system and acoustic emission(AE)monitoring system were used to monitor the entire rockburst process in real *** experimental results show that when the initial burial depth increases from 928 m to 1320 m,the proportion of large fracture scale in rockburst increases by 154.54%,and the AE energy increases by 565.63%,reflecting that the degree and severity of rockburst increase with the increase of burial *** then,two mechanisms are proposed to explain this effect,including(i)the increase of initial geostress improves the energy storage capacity of gneiss,and then,the excess energy which can be converted into kinetic energy of debris ejection increases,consequently,a more pronounced violent ejection phenomenon is observed at rockburst;(ii)the increase of initial geostress causes more sufficient plate cracks of gneiss after unloading ofσh,which provides a basis for more severe ejection of ***’s more,a precursor with clear physical meaning for rockburst is proposed under the framework of dynamic response process of crack ***,potential value in long term rockburst warning of the precursor obtained in this study is shown via the comparison of conventional precursor.

关键词： Traffic Engineering Gneiss Rockburst Crack propagation Excess energy Precursor characteristic

Self-adaptive hydrogel for breast cancer therapy via accurate tumor elimination and on-demand adipose tissue regeneration

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Chinese Chemical Letters 2024年第1期35卷 371-378页

作者： ran Tian Xinyu Qiu Wenyun Mu Bolei Cai Zhongning Liu Shiyu Liu Xin Chen School of Chemical Engineering and Technology Department of Chemical EngineeringShaanxi Key Laboratory of Energy Chemical Process IntensificationXi'an Jiao Tong UniversityXi'an 710049China School of Stomatology State Key Laboratory of Military Stomatology&National Clinical Research Center for Oral Diseases&Shaanxi Clinical Research Center for Oral DiseasesDepartment of Preventive DentistryThe Fourth Military Medical UniversityXi'an 710032China School of Stomatology State Key Laboratory of Military StomatologyDepartment of Oral and Maxillofacial SurgeryThe Fourth Military Medical UniversityXi'an 710032China Department of Prosthodontics Peking University School and Hospital of StomatologyNational Clinical Research Center for Oral DiseasesNational Engineering Laboratory for Digital and Material Technology of StomatologyBeijing Key Laboratory of Digital StomatologyBeijing 100081China School of Stomatology State Key Laboratory of Military StomatologyNational Clinical Research Center for Oral DiseasesShaanxi International Joint Research Center for Oral DiseasesCenter for Tissue EngineeringThe Fourth Military Medical UniversityXi'an 710032China

The irregular defects and residual tumor tissue after surgery are challenges for effective breast cancer ***,a smart hydrogel with self-adaptable size and dual responsive cargos release was fabricated to treat breast cancer via accurate tumor elimination,on-demand adipose tissue regeneration and effective infection *** hydrogel consisted of thiol groups ended polyethylene glycol(SH-PEG-SH)and doxorubicin encapsulated mesoporous silica nanocarriers(DOX@MSNs)double crosslinked hyaluronic acid(HA)after loading of antibacterial peptides(AP)and adipose-derived stem cells(ADSCs).A pH-cleavable unsaturated amide bond was pre-introduced between MSNs and HA frame to perform the tumor-specific acidic environment dependent DOX@MSNs release,meanwhile an esterase degradable glyceryl dimethacrylate cap was grafted on MSNs,which contributed to the selective chemotherapy in tumor cells with over-expressed *** bond cleavage between MSNs and HA would also cause the swelling of the hydrogel,which not only provide sufficient space for the growth of ADSCs,but allows the hydrogel to fully fill the irregular defects generated by surgery and residual tumor atrophy,resulting in the on-demand regeneration of adipose ***,the sustained release of AP could be simultaneously triggered along with the size change of hydrogel,which further avoided bacterial infection to promote tissue regeneration.

关键词： Smart hydrogel with self-adaptable size Breast cancer therapy Dual responsive cargoes release Selective tumor elimination On-demand adipose tissue regeneration Effective bacteria inhibition

Comparative Study of 3D-Printed Porous Titanium Alloy with Rod Designs of Three Different Geometric Structures for Orthopaedic Implantation

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 54-66页

作者： Jiaxin Li Haozhang Zhong Bojun Cao Zhaoyang ran Jia Tan Liang Deng Yongqiang Hao Jinglong Yan Department of Orthopedics The Second Affiliated Hospital of Harbin Medical UniversityHarbin150001China Shanghai Engineering Research Center of Innovative Orthopaedic Instruments and Personalized Medicine Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai200011China Institute of Materials Modification and Modeling Shanghai Jiao Tong UniversityShanghai200240China

Porous titanium alloy is currently widely used in clinical treatment of orthopaedic diseases for its lower elastic modulus and ability to integrate with bone *** the micro-level,cells can respond to different geometries,and at the macro-level,the geometric design of implants will also affect the biological function of *** this study,three kinds of porous scaffolds with square,triangular and circle rod shapes were designed and 3D *** study observed the proliferation and differentiation of MC3T3-E1 cells during surface culture of the three types of *** also evaluated the characteristics of the three scaffolds by means of compression tests and scanning electron microscopy to provide a reference for the design of porous titanium alloy implants for clinical *** trends of cell proliferation and gene expression between the three types of scaffolds were observed after treatment with two *** results show that the square rod porous scaffolds have the best proliferative and osteogenic activities,and these findings may be due to differences in piezo-type mechanosensitive ion channel component 1(Piezo1)and Yes-associated protein(YAP)expression caused by the macro-geometric topography.

关键词： Porous titanium scaffolds Geometric morphology Cell proliferation Structural design