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Experimental and numerical study on protective effect of RC blast wall against air shock wave

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Defence Technology（防务技术） 2024年第1期31卷 567-579页

作者： Xin-zhe nian Quan-min Xie Xin-li Kong Ying-kang yao Kui Huang State Key Laboratory of Precision Blasting Jianghan UniversityWuhan430056China Hubei Key Laboratory of Blasting Engineering Jianghan UniversityWuhan430056China Hubei(Wuhan)Institute of Explosion and Blasting Technology Jianghan UniversityWuhan430056China College of Defense Engineering Army Engineering University of PLANanjing210007China Institute of Defense Engineering AMSPLALuoyang471023China

Prototype experiments were carried out on the explosion-proof performance of the RC blast *** mass of TNT detonated in the experiments is 5 kg and 20 kg *** shock wave overpressure was tested in different *** above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP *** results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP *** dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was *** to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are *** above results can provide a reference for the design and construction of the reinforced concrete blast wall.

关键词： Blast wall Shock wave Diffraction Overpressure Protection

Synthesis and applications of carbon nanospheres:A review

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Particuology 2024年第4期87卷 325-338页

作者： Yaqi yao Jinming xu Yanqiang Huang Tao Zhang State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

The synthesis of carbon nanospheres(CNS)has developed rapidly in recent years,and they are widely used owing to the tunability of their porous structures and surface properties and the unique hydrodynamic advantages conferred by their spherical *** review summarizes the methods used to synthesize CNS and their applications in various *** review first describes the four main methods of CNS synthesis,*** template,spray-drying,hydrothermal carbonization,Stöber and chemical vapor depo-sition ***,applications in the fields of energy storage,adsorption,biological medicine,and catalysis are ***,some insights on the development and design of CNS are presented.

关键词： Carbon nanosphere Synthesis Application

Solubility determination and comparison ofβ-HMX and RDX in two binary mixed solvents(acetonitrile+water,nitric acid+water)

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Chinese Journal of Chemical Engineering 2024年第5期69卷 238-249页

作者： Yuehua yao Fan Wang Yinguang xu Zishuai xu Lizhen Chen Jianlong Wang School of Chemistry and Chemical Engineering North University of ChinaTaiyuan 030051China Gansu Yinguang Chemical Industry Group Co.Ltd. Baiyin 730900China

In order to remove hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX),the main impurity,in process of polymorphic transformation of octrahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),the solubility ofβ-HMX and RDX in acetonitrile(ACN)+water in the temperature range of 288.15-333.15 K and in nitric acid(HNO_(3))+water in the temperature range of 298.15-333.15 K were measured by laser dynamic *** results showed that the solubility of bothβ-HMX and RDX in binary mixed solvents increased monotonously as the temperature increase at a given solvent composition or with increasing of mole fraction of solvent(ACN and nitric acid).Solubility data were well correlated by the modified Apelblat equation,Jouyban-Acree model,Yaws equation and van't Hoff equation,and the Yaws equation achieved the best fitting results according to the relative error and the mean square error ***,the solubility ofβ-HMX and RDX in binary mixed solvent was compared,based on the solubility difference and the solvent's own properties,the best separation degree ofβ-HMX and RDX was found when the mole fraction of nitric acid was 0.22 at room temperature,which provided data support for HMX crystallization in mixed *** solubility differences between RDX andβ-HMX in mixed solvents were explained from the formation of intermolecular and intramolecular hydrogen bonds.

关键词： Solubility Octrahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine Hexahydro-1,3,5-trinitro-1,3,5-triazine Separation Model Hydrogen bond

Evaluation on Configuration Stiffness of Overconstrained 2R1T Parallel Mechanisms

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 62-82页

作者： xuejian Ma Zhenghe xu Yundou xu Yu Wang Jiantao yao Yongsheng Zhao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao 066004China Key Laboratory of Advanced Forging and Stamping Technology and Science of Ministry of National Education Yanshan UniversityQinhuangdao 066004China

Currently,two rotations and one translation(2R1T)three-degree-of-freedom(DOF)parallel mechanisms(PMs)are widely applied in five-DOF hybrid machining ***,there is a lack of an effective method to evaluate the configuration stiffness of mechanisms during the mechanism design *** is a challenge to select appropriate 2R1T PMs with excellent stiffness performance during the design *** the operational status of 2R1T PMs,the bending and torsional stiffness are considered as indices to evaluate PMs'configuration ***,a specific method is proposed to calculate these stiffness ***,the various types of structural and driving stiffness for each branch are assessed and their specific values ***,a rigid-flexible coupled force model for the over-constrained 2R1T PM is established,and the proposed evaluation method is used to analyze the configuration stiffness of the five 2R1T PMs in the entire ***,the driving force and constraint force of each branch in the whole working space are calculated to further elucidate the stiffness evaluating results by using the proposed method *** obtained results demonstrate that the bending and torsional stiffness of the 2RPU/UPR/RPR mechanism along the x and y-directions are larger than the other four mechanisms.

关键词： Parallel mechanism Stiffness Over-constrained Three degrees of freedom

Reshaping the Cortical Connectivity Gradient by Long-Term Cognitive Training During Development

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Neuroscience Bulletin 2024年第1期40卷 50-64页

作者： Tianyong xu Yunying Wu Yi Zhang Xi-nian Zuo Feiyan Chen Changsong Zhou Bio-X Laboratory School of PhysicsZhejiang UniversityHangzhou 310027China Qiushi Academy for Advanced Studies Zhejiang UniversityHangzhou 310027China State Key Laboratory of Modern Optical Instrumentation College of Optical Science and EngineeringZhejiang UniversityHangzhou 310027China State Key Laboratory of Cognitive Neuroscience and Learning Bejing Normal UniversityBeijing 100875China Developmental Population Neuroscience Research Center IDG/McGovern Institute for Brain ResearchBeijing Normal UniversityBeijing 100875China Zhejiang Province Key Laboratory of Quantum Technology and Devices Zhejiang UniversityHangzhou 310027China Department of Physics Centre for Nonlinear Studies and Beijing-Hong Kong-Singapore Joint Centre for Nonlinear and Complex Systems(Hong Kong)Institute of Computational and Theoretical StudiesHong Kong Baptist UniversityHong Kong 999077China

The organization of the brain follows a topologi-cal hierarchy that changes dynamically during ***,it remains unknown whether and how cognitive training administered over multiple years during develop-ment can modify this hierarchical *** measuring the brain and behavior of school children who had carried out abacus-based mental calculation(AMC)training for five years(starting from 7 years to 12 years old)in pre-training and post-training,we revealed the reshaping effect of long-term AMC intervention during development on the brain hierarchical *** observed the development-induced emergence of the default network,AMC training-promoted shifting,and regional changes in cortical ***,the training-induced gradient changes were located in visual and somatomotor areas in association with the visuospatial/motor-imagery *** found that gradient-based features can predict the math ability within *** findings provide novel insights into the dynamic nature of network recruitment impacted by long-term cognitive training during development.

关键词： Connectivity gradient Cognitive training Development Neural plasticity Abacus-based mental calculation

Nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in aerospace community:a comparative analysis

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International Journal of Extreme Manufacturing 2024年第2期6卷 190-271页

作者： Guolong Zhao Biao Zhao Wenfeng Ding Lianjia Xin Zhiwen nian Jianhao Peng Ning He Jiuhua xu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016People’s Republic of China

The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,such as thin-walled structures,microchannels,and complex *** machining is the main material removal process for the vast majority of aerospace ***,many problems exist,including severe and rapid tool wear,low machining efficiency,and poor surface *** energy-assisted mechanical machining is a hybrid process that uses nontraditional energies(vibration,laser,electricity,etc)to improve the machinability of local materials and decrease the burden of mechanical *** provides a feasible and promising method to improve the material removal rate and surface quality,reduce process forces,and prolong tool ***,systematic reviews of this technology are lacking with respect to the current research status and development *** paper reviews the recent progress in the nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in the aerospace *** addition,this paper focuses on the processing principles,material responses under nontraditional energy,resultant forces and temperatures,material removal mechanisms,and applications of these processes,including vibration-,laser-,electric-,magnetic-,chemical-,advanced coolant-,and hybrid nontraditional energy-assisted mechanical ***,a comprehensive summary of the principles,advantages,and limitations of each hybrid process is provided,and future perspectives on forward design,device development,and sustainability of nontraditional energy-assisted mechanical machining processes are discussed.

关键词： difficult-to-cut materials geometrically complex components nontraditional energy mechanical machining aerospace community

Optimized Auxiliary Frequency Control of Wind Farm Based on Piecewise Reduced-order Frequency Response Model

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 791-802页

作者： xu Zhang Chen Zhao Junchao Ma Long Zhang Dan Sun Chenxu Wang Yan Peng Heng nian the School of Electrical Engineering Zhejiang UniversityHangzhou 310058China Electric Power Research Institute of State Grid Zhejiang Electric Power Corporation Hangzhou 310014China

With the increasing wind power penetration in the power system,the auxiliary frequency control(AFC)of wind farm(WF)has been widely *** traditional system frequency response(SFR)model is not suitable for the wind power generation system due to its poor accuracy and *** this paper,a piecewise reduced-order frequency response(PROFR)model is proposed,and an optimized auxiliary frequency control(O-AFC)scheme of WF based on the P-ROFR model is ***,a full-order frequency response model considering the change in operating point of wind turbine is established to improve the *** order to simplify the fullorder model,a P-ROFR model with second-order structure and high accuracy at each frequency response stage is *** on the proposed P-ROFR model,the relationship between the frequency response indexes and the auxiliary frequency controller coefficients is expressed ***,an OAFC scheme with the derived explicit expression as the optimization objective is proposed in order to improve the frequency support capability on the premise of ensuring the full release of the rotor kinetic energy and the full use of the effect of time delay on frequency ***,the effectiveness of the proposed P-ROFR model and the performance of the proposed OAFC scheme are verified by simulation studies.

关键词： Frequency response piecewise reduced-order wind farm auxiliary frequency control

Skin Microbiota and the Skin Barrier

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International Journal of Dermatology and Venereology 2024年第1期7卷 18-26页

作者： Ming-Yang Wu xu yao Department of Allergy and Rheumatology Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIsHospital for Skin Diseases(Institute of Dermatology)Chinese Academy of Medical Sciences and Peking Union Medical CollegeNanjingJiangsu 210042China Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs NanjingJiangsu 210042China

The skin constitutes the primary barrier between the human body and the external *** skin microbiome plays an important role in the microecosystem on the skin surface and mediates multiple facets of the skin barrier function,including physical,chemical,microbial,and immune *** this review,we discuss the host-microbiota interactions in barrier maintenance and disruption,implications for skin disorders such as atopic dermatitis,psoriasis,and rosacea,and the latest strategies for targeting the skin microbiota to improve the skin barrier.

关键词： skin barrier microbiota immune atopic dermatitis

Intravitreal conbercept injection with panretinal photocoagulation for high-risk proliferative diabetic retinopathy with vitreous hemorrhage

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International Journal of Ophthalmology(English edition) 2024年第6期17卷 1066-1072页

作者： yao xu Qing Ye Wei Shen Department of Ophthalmology the Fourth Affiliated Hospital of Soochow UniversitySuzhou 215000Jiangsu ProvinceChina Department of Ophthalmology Suzhou Kowloon HospitalShanghai Jiao Tong University School of MedcineSuzhou 215000Jiangsu ProvinceChina Department of Ophthalmology the First Affiliated Hospital of Soochow UniversitySuzhou 215000Jiangsu ProvinceChina

AIM:To assess the clinical efficacy and safety of combining panretinal photocoagulation(PRP)with intravitreal conbercept(IVC)injections for patients with high-risk proliferative diabetic retinopathy(HR-PDR)complicated by mild or moderate vitreous hemorrhage(VH),with or without diabetic macular edema(DME).METHODS:Patients diagnosed with VH with/without DME secondary to HR-PDR and received PRP combined with IVC injections were recruited in this retrospective *** establishing the patient’s diagnosis,an initial IVC was performed,followed by prompt administration of *** cases who significant bleeding persisted and impeded the laser operation,IVC was sustained before supplementing with *** the completion of PRP,patients were meticulously monitored for a minimum of six *** therapy and IVC injections were judiciously adjusted based on fundus fluorescein angiography(FFA)*** effect and the incidence of adverse events were ***:Out of 42 patients(74 eyes),29 were male and 13 were female,with a mean age of 59.17±12.74y(33-84y).The diabetic history was between 1wk and 26y,and the interval between the onset of visual symptoms and diagnosis of HR-PDR was *** affected eye received 2.59±1.87(1-10)IVC injections and underwent 5.5±1.02(4-8)sessions of *** these,68 eyes received PRP following 1 IVC injection,5 eyes after 2 IVC injections,and 1 eye after 3 IVC *** absorption of VH was observed in all 74 eyes 5-50wk after initial treatment,with resolution of DME in 51 eyes 3-48wk after initial treatment.A newly developed epiretinal membrane was noted in one *** acuity significantly improved in 25 *** complications such as glaucoma,retinal detachment,or endophthalmitis were ***:The study suggests that the combination of PRP with IVC injections is an effective and safe modality for treating diabetic VH in patients with HR-PDR.

关键词： conbercept panretinal photocoagulation high-risk proliferative diabetic retinopathy vitreous hemorrhage