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Influence of magnetically constricted arc traverse speed (MCATS) on tensile properties and microstructural characteristics of welded Inconel 718 alloy sheets

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Defence Technology（防务技术） 2021年第4期17卷 1395-1413页

作者： Tushar Sonar Visvalingam Balasubramanian Sudersanan Malarvizhi Thiruvenkatam Venkateswaran Dhenuvakonda Sivakumar Centre for Materials Joining and Research(CEMAJOR) Department of Manufacturing EngineeringAnnamalai UniversityAnnamalai Nagar608002Tamilnadu StateIndia Heat Treatment and Welding Metallurgy Division(HWMD) Materials and Metallurgy Group(MMG)Vikram Sarabhai Space Centre(VSSC)ISROThiruvananthpuram695022Kerala StateIndia

The magnetically constricted arc technique was implemented to mitigate the heat input related metallurgical problems in Gas Tungsten Arc Welding(GTAW)of Inconel 718 alloy particularly Nb segregation and subsequent laves phase evolution in fusion *** paper reports the direct effect of magnetically constricted arc traverse speed(MCATS)on bead profile,tensile properties and microstructural evolution of Inconel 718 alloy sheets joined by Gas Tungsten Constricted Arc Welding(GTCAW)*** mechanism amenable for the microstructural modification and corresponding influence on the tensile properties of joints is investigated both in qualitative and quantitative manner related to the mechanics of arc constriction and *** is correlated to the solidification conditions during *** relationship between MCATS and Arc Constriction Current(ACC)was *** interaction effect on the magnetic arc constriction and joint performance was *** showed that the joints fabricated using CATS of 70 mm/min exhibited superior tensile properties(98.39% of base metal strength with 31.50% elongation).It is attributed to the grain refinement in fusion zone microstructure leading to the evolution of finer,discrete laves phase in interdendritic areas.

关键词： GTCA welding Inconel 718 alloy Magnetically constricted arc traverse speed Tensile properties Microstructure Laves phase

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Crack propagation with different radius local random damage based on peridynamic theory

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Frontiers of Structural and Civil Engineering 2021年第5期15卷 1238-1248页

作者： Jinhai ZHAO Li TAN Xiaojing DOU department of Civil Engineering Zhejiang University City CollegeHangzhou 3100015China College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China College of Civil Engineering Tongji UniversityShanghai 200092China Shanghai Baoye group Corp. Ltd.Shanghai 200941China

Drawing from the advantages of Classical Mechanics,the peridynamic theory can clarify the crack propagation mechanism by an integral solution without initially setting the factitious crack and crack *** study implements the peridynamic theory by subjecting bilateral notch cracked specimens to the conditions of no local damage,small radius local damage,and large radius local ***,to study the effects of local stochastic damage with different radii on the crack propagation path and Y-direction displacement,a comparison and contact methodology was adopted,in which the crack propagation paths under uniaxial tension and displacement in the Y-direction were compared and *** method can be applied to steel structures under similar local random damage conditions.

关键词： peridynamics stochastic damage bilateral notch crack

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Climate change vulnerability assessment in the new urban planning process in Tanzania

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Regional Sustainability 2024年第3期 3-13页

作者： Issa NYASHILU Robert KIUNSI Alphonce KYESSI Vice President's Office Government City department of Environmental Engineering and Technology Ardhi University Institute of Human Settlements Studies Ardhi University

Climate change vulnerability assessment is an essential tool for identifying regions that are most susceptible to the impacts of climate change and designing effective adaptation actions that can reduce vulnerability and enhance long-term resilience of these regions. This study explored a framework for climate change vulnerability assessment in the new urban planning process in Jangwani Ward, Tanzania. Specifically, taking flood as an example, this study highlighted the steps and methods for climate change vulnerability assessment in the new urban planning process. In the study area, 95 households were selected and interviewed through purposeful sampling. Additionally, 10 respondents(4 females and 6 males) were interviewed for Focus group Discussion(FGD), and 3 respondents(1 female and 2 males) were selected for Key Informant Interviews(KII) at the Ministry of Lands, Housing and Human Settlements Development. This study indicated that climate change vulnerability assessment framework involves the assessment of climatic hazards, risk elements, and adaptive capacity, and the determination of vulnerability levels. The average hazard risk rating of flood was 2.3. Socioeconomic and livelihood activities and physical infrastructures both had the average risk element rating of 3.0, and ecosystems had the average risk element rating of 2.9. Adaptive capacity ratings of knowledge, technology, economy or finance, and institution were 1.6, 1.9, 1.4, and 2.2, respectively. The vulnerability levels of socioeconomic and livelihood activities and physical infrastructure were very high(4.0). Ecosystems had a high vulnerability level(3.8) to flood. The very high vulnerability level of socioeconomic and livelihood activities was driven by high exposure and sensitivity to risk elements and low adaptive capacity. The study recommends adoption of the new urban planning process including preparation, planning, implementation, and monitoring-evaluation-review phases that integrates climat

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Early assessment of the safety and immunogenicity of a third dose(booster)of COVID-19 immunization in Chinese adults

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Frontiers of Medicine 2022年第1期16卷 93-101页

作者： Yuntao Zhang Yunkai Yang Niu Qiao Xuewei Wang Ling Ding Xiujuan Zhu Yu Liang Zibo Han Feng Liu Xinxin Zhang Xiaoming Yang China National Biotec group Company Limited Beijing 100024China Shanghai Institute of Hematology State Key Laboratory of Medical GenomicsNational Research Center for Translational Medicine at ShanghaiRuijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200025China Beijing Institute of Biological Products China National Biotec Group Company LimitedBeijing 100176China National Vaccine and Serum Institute China National Biotec Group Company LimitedBeijing 101111China department of Infectious Diseases Research Laboratory of Clinical VirologyRuijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200025China

Inducing durable and effective immunity against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)via vaccination is essential to combat the current pandemic of coronavirus disease 2019(COVID-19).It has been noticed that the strength of anti-COVID-19 vaccination-induced immunity fades over time,which calls for an additional vaccination regime,as known as booster immunization,to restore immunity among previously vaccinated *** we report a pilot open-label trial of a third dose of BBIBP-CorV,an inactivated SARS-CoV-2 vaccine(Vero cell),on 136 participants aged between 18 to 63 *** and immunogenicity in terms of neutralizing antibody titers and cytokine/chemokine responses were analyzed as the main endpoint until day *** systemic reactogenicity was either absent or mild,SARS-CoV-2-specific neutralizing antibody titers rapidly arose in all participants within 4 weeks,surpassing the peak antibody titers elicited by the initial two-dose immunization *** increases of cellular immunity-associated cytokines and chemokines were also detected in the majority of participants after the third ***,in an exploratory study,a newly developed recombinant protein vaccine,NVSI-06-08(CHO Cells),was found to be safe and even more effective than BBIBP-CorV in eliciting humoral immune responses in BBIBP-CorV-primed ***,these results indicate that a third immunization schedule with either homologous or heterologous vaccine showed favorable safety profiles and restored potent SARS-CoV-2-specific immunity,providing support for further trials of booster vaccination in larger populations.

关键词： COVID-19 SARS-CoV-2 vaccine immunization booster immunization

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Exploration of the glutamate-mediated retinal excitotoxic damage: a rat model of retinal neurodegeneration

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International Journal of Ophthalmology(English edition) 2018年第11期11卷 1746-1754页

作者： Ling Gao Qi-Jun Zheng Li-Qian-Yu Ai Kai-Jian Chen Yuan-Guo Zhou Jian Ye Wei Liu department of Ophthalmology Institute of Surgery Research Daping Hospital Army Medical University Molecular biology Center State Key Laboratory of Trauma Burn and Combined Injury Research Institute of Surgery and Daping Hospital Army Medical University

AIM： To explore the more suitable concentration of glutamate or N-methyl-D-aspartic acid（NMDA） for intravitreal injection to establish a rat model of retinal neurodegeneration. METHODS： We injected different doses of glutamate（20 or 50 nmol） or NMDA（40 nmol） into the vitreous chambers of rats, then measured the concentration of glutamate and retinal thickness, quantified apoptotic cells and determined the degree of tau hyperphosphorylation at different time points. T-test was used for comparison of two groups. One-way ANOVA and Turkey＇s multiple comparisons test were used for comparisons of different groups, and P values below 0.05 were considered statistically ***： The glutamate level in the rats treated with 50 nmol of glutamate was twice that of the control group and persisted two weeks. Seven days after intravitreal injection of 50 nmol of glutamate, three parameters [inner retinal thickness（IRT）, retinal thickness（RT） and ganglion cell layer（GCL） cell number] were reduced significantly. Furthermore, numerous TUNEL-positive cells were observed in the GCL one day after intravitreal injection of 50 nmol of glutamate, the expression of the apoptosisrelated factor cleaved casepase-3 was markedly increased compared with the expression levels in the other treatment groups, and the expression levels of tau s396 and tau s404 were significantly increased compared with those in the control ***： This study demonstrates that the intravitreal injection of 50 nmol of glutamate can establish the more effective retinal neurodegeneration animal model relative to other treatment groups.

关键词： retinal neurodegeneration glutamate excitotoxicity animal model glaucoma

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A Multi-step Thermodynamic Model for Alumina Formation during Aluminum Deoxidation in Fe–O–Al Melt

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 272-280页

作者： Guo-Cheng Wang Qi Wang Sheng-Li Li Xin-Gang Ai Da-Peng Li Key Laboratory of Chemical Metallurgy Engineering Liaoning Province University of Science and Technology Liaoning Jiangxi University of Science and Technology Benxi Steel group Corporation

Based on the two-step nucleation mechanism, a multi-step thermodynamic model for alumina inclusion for- mation during aluminum deoxidation process was proposed in Fe-O-Al melt. Thermodynamic properties of metastable intermediates including （Al2O3）n clusters for prenucleation and α-Al2O3 nanoparticle for growth process were calculated using density functional theory. Furthermore, Gibbs free energy change of forming the intermediate by reaction between the dissolved aluminum （Al） and oxygen （O） in the melt was calculated. The results indicated that the thermodynamics of （Al2O3）n at steelmaking temperature are dependent on their structures, while that of α-Al2O3 nanoparticle are dependent on their size. The nuclei of α-Al2O3 which was originated from （Al2O3）n aggregated under a high supersaturation ratio of Al and O（Rs） in the melt. There existing excess oxygen because of the low Rs, but the secondary inclusions will be formed during the cooling process due to the excess oxygen. The nuclei lager than 20 nm can grow up spontaneously and instantaneously into primary inclusions because of thermodynamic drive. It is difficult to control the size of α-Al2O3 to be less than 20 nm, in the aluminum deoxidation process of the current conditions of steelmaking.

关键词： Multi-step thermodynamics Fe-O-AI melt Aluminum deoxidation DFT Nano-α-Al2O3

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Enhancing clinical proficiency through laparoscopic training using Japanese origami

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Laparoscopic, Endoscopic, and Robotic Surgery 2024年第3期7卷 102-106页

作者： Furukawa S. Hiraki M. Kimura N. Sakurai R. Kohata R. Kohya N. Sakai M. Ikubo A. Samejima R. department of Surgery Japanese Red Cross Society Karatsu Red Cross Hospital Saga 847-8588 Japan department of Surgery Saga University Faculty of Medicine Saga 849-8501 Japan

Objective: This study aimed to investigate the clinical efficacy of laparoscopic training using origami, a traditional Japanese papercraft, using laparoscopic forceps to create origami cranes. Methods: In this retrospective study, 4 surgeons were randomly divided into 2 groups: The training group, consisting of surgeons 1 and 2, and the non-training group, consisting of surgeons 3 and 4. Over the course of a one-year study period, the training group regularly underwent laparoscopic surgery training with a dry box, wherein they folded a total of 1000 origami cranes using laparoscopic instruments. The non-training group periodically underwent common laparoscopic surgery training of techniques such as suturing and ligation. Each surgeon regularly performed the transabdominal preperitoneal approach for inguinal hernias. Each training was conducted concurrently with the surgeries. The procedure time (peritoneum detachment, mesh placement, and closure of the peritoneum), total operation time (time from peritoneum detachment to closure of the peritoneum), and surgical outcomes were examined. Results: The training group showed greater improvement in the total operation time and more stable performance than the non-training group. Additionally, the time taken for peritoneum detachment was significantly shorter in the training group. Conclusion: Laparoscopic training using origami has the potential to enhance laparoscopic surgical skills and improve surgical outcomes. © 2024 Zhejiang University

关键词： Dry box Laparoscopic surgery Origami Training

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Applied Mathematics and Mechanics(English Edition) 2001年第12期22卷 1429-1435页

作者：吕念春程靳程云虹屈德志 department of Astronautics and Mechanics Harbin Institute of Technology Harbin 150001 P R China department of Civil Engineering Northeastern University Shenyang 110006 P R China Compressive Vessel Manufacturer of Constructive Installation group Company of Daqing Daqing 163711 P R China

By the theory of complex functions, a penny-shaped crack on axially symmetric propagating problems for composite materials, was studied. The general representations of the analytical solutions with arbitrary index of self-similarity, were presented for fracture elastodynamics problems on axially symmetry by the ways of self-similarity under the ladder-shaped loads. The problems dealt with can be transformed into Riemann-Hilbert problems and their closed analytical solutions are obtained rather simple by this method. After those analytical solutions are utilized by using the method of rotational superposition theorem in conjunction with that of Smirnov-Sobolev, the solutions of arbitrary complicated problems can be obtained.

关键词： penny-shaped crack axially symmetric composite materials analytical solutions

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Modifying glass fiber surface with grafting acrylamide by UV-grafting copolymerization for preparation of glass fiber reinforced PVDF composite membrane

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Journal of Environmental Sciences 2016年第1期28卷 208-217页

作者： Nan Luo Hui Zhong Min Yang Xing Yuan Yaobo Fan group of Membrane Separation Technique Department of Water Pollution Control Technology Research Center for Eco-Environmental Sciences (RCEES) Chinese Academy of Sciences (CAS) State Key Joint Laboratory of Environmental Simulation and Pollution Control Research Center for Eco-Environmental Sciences (RCEES)Chinese Academy of Sciences (CAS)

Experimental design and response surface methodology（RSM） were used to optimize the modification of conditions for glass surface grafting with acrylamide（AM） monomer for preparation of a glass fiber reinforced poly（vinylidene fluoride）（PVDF） composite membrane（GFRP-CM）. The factors considered for experimental design were the UV（ultraviolet）-irradiation time, the concentrations of the initiator and solvent, and the kinds and concentrations of the silane coupling agent. The optimum operating conditions determined were UV-irradiation time of 25 min, an initiator concentration of 0–0.25 wt.%,solvent of N-Dimethylacetamide（DMAC）, and silane coupling agent KH570 with a concentration of 7 wt.%. The obtained optimal parameters were located in the valid region and the experimental confirmation tests conducted showed good accordance between predicted and experimental values. Under these optimal conditions, the water absorption of the grafted modified glass fiber was improved from 13.6% to 23%; the tensile strength was enhanced and the peeling strength of the glass fiber reinforced PVDF composite membrane was improved by 23.7% and 32.6% with an AM concentration at 1 wt.% and 2 wt.%. The surface composition and microstructure of AM grafted glass fiber were studied via several techniques including Field Emission Scanning Electron Microscopy（FESEM）, Fourier transform infrared spectroscopy-attenuated total reflectance（FTIR-ATR） and energy dispersive X-ray spectroscopy（EDX）. The analysis of the EDX and FTIR-ATR results confirmed that the AM was grafted to the glass fiber successfully by detecting and proving the existence of nitrogen atoms in the GFRP-CM.

关键词： Glass fibers Polymer-matrix composites Coupling agents UV-grafting copolymerization Interfacial strength

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Rational Solutions of High-Order Algebraic Ordinary Differential Equations

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Journal of Systems Science & Complexity 2020年第3期33卷 821-835页

作者： VO Thieu N. ZHANG Yi Fractional Calculus Optimization and Algebra Research GroupFaculty of Mathematics and StatisticsTon Duc Thang UniversityHo Chi Minh CityVietnam Johann Radon Institute for Computational and Applied Mathematics(RICAM) Austrian Academy of SciencesAustria department of Mathematical Sciences The University of Texas at Dallas(UTD)USA

This paper considers algebraic ordinary differential equations(AODEs)and study their polynomial and rational *** authors first prove a sufficient condition for the existence of a bound on the degree of the possible polynomial solutions to an *** AODE satisfying this condition is called *** the authors prove that some common classes of low-order AODEs are *** rational solutions,the authors determine a class of AODEs,which are called maximally comparable,such that the possible poles of any rational solutions are recognizable from their *** generalizes the well-known fact that any pole of rational solutions to a linear ODE is contained in the set of zeros of its leading ***,the authors develop an algorithm to compute all rational solutions of certain maximally comparable AODEs,which is applicable to 78.54%of the AODEs in Kamke's collection of standard differential equations.

关键词： Algebraic ordinary differential equations algorithms polynomial solutions rational solutions

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