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Microstructure and Property Relationships in Resistance Spot Weld between 7114 Interstitial Free Steel and 304 Austenitic Stainless Steel

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Journal of Materials Science & Technology 2006年第3期22卷 375-381页

作者： Ahmet Hasanba■o■lu Ramazan Kaar Department of Metal Education Karabük Technical Education Faculty Karabük 78100 Turkey

Due to the differences in physical, chemical and mechanical properties of the base metals, the resistance spot welding of dissimilar materials is generally more challenging than that of similar materials. The influence of the primary welding parameters affecting the heat input such as peak current on the morphology, microhardness, and tensile shear load bearing capacity of dissimilar welds between 304 grades austenitic and 7114 grade interstitial free steel has been investigated in this study. The optimum welding parameters producing maximum joint strength were established at a peak current of 9 kA, where the electrode force is kept 6×10^-5 Pa and weld time is kept constant 17 cycles, respectively. The primary cause of weakening the weldment is identified as the excessive grain growing region of heat affected zone （HAZ） in case of 7114 grade interstitial free steel.

关键词： Resistance spot weld Interstitial free steel Austenitic stainless steel

Characterization and antifouling activity analysis of extracellular polymeric substances produced by an epibiotic bacterial strain Kocuria flava associated with the green macroalga Ulva lactuca

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Acta Oceanologica Sinica 2021年第4期40卷 107-115页

作者： Mohammad Abdulaziz ba-akdah Sathianeson Satheesh Department of Marine Biology Faculty of Marine SciencesKing Abdulaziz UniversityJeddah 21589Saudi Arabia

Extracellular polymeric substances(EPS)are present externally to the microorganisms and play an important role in attachment and biofilm *** polymers possess antibacterial and antifouling *** this study,the antifouling activity of EPS produced by an epibiotic bacterium associated with macroalga Ulva lactuca was assessed against fouling bacteria and barnacle *** indicate that the EPS isolated from the epibiotic bacterium inhibits the biofilm formation of the bacteria without much antibacterial ***,the EPS reduced the settlement of barnacle larvae on the hard substrate under laboratory *** epibiotic bacterium was identified as Kocuria flava based on 16 S rRNA gene *** EPS was further analysed using Fourier transform infrared(FT-IR),nuclear magnetic resonance(NMR)and X-ray diffraction(XRD)to understand the biochemical *** analysis revealed the presence of polysaccharides,proteins,acetyl amine and succinyl *** electron microscope analysis indicated that the EPS consisted of aggregated and irregular sphere-shaped particles.

关键词： biofouling antifouling Kocuria flava exopolymers antibiofilm activity Red Sea

Palladium-induced electron-transfer reaction of difluorodiiodomethane with alkenes

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Chinese Journal of Chemistry 1996年第6期14卷 549-554页

作者： Li, ar Chen, QY CHINESE ACAD SCI SHANGHAI INST ORGAN CHEMSHANGHAI 200032PEOPLES R CHINA

The addition reaction of difluorodiiodomethane (1) with alkenes in the presence of PdCl2(PPh(3))(2) or Pd(PPh(3))(4) afforded the corresponding iododifluoromethylated compounds in excellent yield.

关键词： difluorodiiodomethane alkenes palladium complex

High-Efficiency DC-DC Converter for Large Input-Voltage Fluctuations in Solar Applications

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Chinese Journal of Electronics 2015年第3期24卷 502-507页

作者： AGUILLON-GarCIA Jacobo baNUELOS-SANCHEZ Pedro SIST Sun Yat-sen University

In the solar energy systems the solar irradiance variation is partially engaged, limiting the converter’s transformation rate for a certain input amount and leaving the rest of energy unconverted. In order to utilize at its maximum the energy provided from a Photovoltaic(PVP) system, this manuscript proposed a topology that can cope with marginal input voltage variations from 60V(DC) up to 1050V(DC) for a steady output voltage of 700V(DC). This output voltage value is suitable for any interlink post-regulation architecture. based on previous observations, this paper presents a wide-input voltage high-efficiency non-isolated single-control topology. Analysis, operating stages, simulations and experimental results for a 3k W prototype are presented.

关键词： DC-DC power converters Energy conversion Photovoltaic system Power conditioning Solar generation

Laser Surface Texturing of Co–Cr–Mo Alloy for Biomedical Applications:A Case Study for the Effects of Process Parameters on Surface Properties

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Journal of Bionic Engineering 2023年第5期20卷 1967-1984页

作者： Şefika Kasman İbrahim Can Uçar Sertan Ozan Department of Mechanical Engineering Dokuz Eylul UniversityIzmir35397Turkey Department of Mechanical Engineering Yozgat Bozok UniversityYozgat66100Turkey

This study presents a comprehensive approach to applying texturing processes created by engraving on the surface of CoCr28Mo alloy workpieces using a 20 W pulsed nanosecond fiber *** hatch strategy and distance,frequency,and scan speed were control parameters for texturing *** effectiveness of the parameters in terms of roughness and contact angle of the texturized surface was *** roughness and contact angle were analyzed using variance analysis to identify each variable's *** has been determined that the roughness of the texture defined by the hatch strategy plays a decisive role in the wettability behavior of the surface;however,the scan speed,frequency,and hatch distance which are among the laser surface texturing conditions are influential in the roughness and contact *** scan speed and hatch distance while decreasing frequency resulted in smoother surfaces,increasing the contact *** having rough surfaces produced with different processing conditions exhibit a super hydrophilic *** contact angle is most sensitive to the hatch distance;however,the frequency has the least influence on the contact *** most and least efficient surface roughness parameters are revealed to be scan speed and hatch distance,respectively.

关键词： Laser surface texturing Co-Cr-Mo alloy Surface roughness Wettability Bionic

A Unified Trajectory Optimization Approach for Long-Term and Reactive Motion Planning of Legged Locomotion

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Journal of Bionic Engineering 2023年第5期20卷 2108-2122页

作者： Yapeng Shi Bin Yu Kaixian ba Mantian Li School of Mechanical Engineering Yanshan UniversityNo.438 West Hebei AvenueQinhuangdao066004HebeiPeople’s Republic of China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001People’s Republic of China

This paper proposes a unified trajectory optimization approach that simultaneously optimizes the trajectory of the center of mass and footholds for legged *** on a generic point-mass model,the approach is formulated as a nonlinear optimization problem,incorporating constraints such as robot kinematics,dynamics,ground reaction forces,obstacles,and target *** unified optimization approach can be applied to both long-term motion planning and the reactive online planning through the use of model predictive control,and it incorporates vector field guidance to converge to the long-term planned *** effectiveness of the approach is demonstrated through simulations and physical experiments,showing its ability to generate a variety of walking and jumping gaits,as well as transitions between them,and to perform reactive walking in obstructed environments.

关键词： Legged locomotion Motion planning Trajectory optimization Bionic robot

An end-to-end 3D seismic simulation of underground structures due to point dislocation source by using an FK-FEM hybrid approach

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Frontiers of Structural and Civil Engineering 2022年第12期16卷 1515-1529页

作者： Zhenning ba Jisai FU Zhihui ZHU Hao ZHONG State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China School of Civil Engineering Tianjin UniversityTianjin 300350China National Engineering Research Center of High Speed Railway Construction Technology Central South UniversityChangsha 410075China School of Civil Engineering Central South UniversityChangsha 410075China

based on the domain reduction idea and artificial boundary substructure method,this paper proposes an FK-FEM hybrid approach by integrating the advantages of FK and FEM(i.e.,FK can efficiently generate high-frequency three translational motion,while FEM has rich elements types and constitutive models).An advantage of this approach is that it realizes the entire process simulation from point dislocation source to underground *** with the plane wave field input method,the FK-FEM hybrid approach can reflect the spatial variability of seismic motion and the influence of source and propagation *** approach can provide an effective solution for seismic analysis of underground structures under scenario of earthquake in regions where strong earthquakes may occur but are not recorded,especially when active faults,crustal,and soil parameters are *** Daikai subway station as an example,the seismic response of the underground structure is simulated after verifying the correctness of the approach and the effects of crustal velocity structure and source parameters on the seismic response of Daikai station are *** this example,the influence of velocity structure on the maximum interlayer displacement angle of underground structure is 96.5%and the change of source parameters can lead to the change of structural failure direction.

关键词： source-to-structure simulation FK-FEM hybrid approach underground structures point dislocation source

Investigation of physicochemical,microbiological and sensorial properties for organic and conventional retail chicken meat

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Food Science and Human Wellness 2021年第2期10卷 183-190页

作者： Berna Capan Aytunga bağdatli Manisa Celal bayar University Faculty of EngineeringDepartment of Food EngineeringYunusemre45140 ManisaTurkey

In this study,the commercially available chicken thigh and breast meat produced by organic and conventional methods were investigated in terms of physicochemical,microbiological and sensorial *** organic chicken breasts had higher fat content than the conventional chicken *** protein content of organic thighs was higher than conventional *** chicken meat contains more mineral substances than conventional chicken meat and has higher pH value,cooking loss and water holding ***-linoleic acid,docosahexaenoic acid was found to be higher in organic chicken *** *** detected in all conventional chicken and 66.66%of organic chicken.

关键词： Organic chicken Conventional chicken Chicken breast Chicken thigh Chicken meat quality Fatty acid composition

Sharkskin-Inspired Magnetoactive Reconfigurable Acoustic Metamaterials

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Research 2020年第1期2020卷 799-811页

作者： Kyung Hoon Lee Kunhao Yu Hasan Al ba’ba’a An Xin Zhangzhengrong Feng Qiming Wang Sonny Astani Department of Civil and Environmental Engineering University of Southern CaliforniaLos AngelesCA 90089USA

Most of the existing acoustic metamaterials rely on architected structures with fixed configurations,and thus,their properties cannot be modulated once the structures are *** active acoustic metamaterials highlight a promising opportunity to on-demand switch property states;however,they typically require tethered loads,such as mechanical compression or pneumatic *** untethered physical stimuli to actively switch property states of acoustic metamaterials remains largely ***,inspired by the sharkskin denticles,we present a class of active acoustic metamaterials whose configurations can be on-demand switched via untethered magnetic fields,thus enabling active switching of acoustic transmission,wave guiding,logic operation,and *** key mechanism relies on magnetically deformable Mie resonator pillar(MRP)arrays that can be tuned between vertical and bent states corresponding to the acoustic forbidding and conducting,*** MRPs are made of a magnetoactive elastomer and feature wavy air channels to enable an artificial Mie resonance within a designed frequency *** Mie resonance induces an acoustic bandgap,which is closed when pillars are selectively bent by a sufficiently large magnetic *** magnetoactive MRPs are further harnessed to design stimuli-controlled reconfigurable acoustic switches,logic gates,and *** of creating the first generation of untethered-stimuli-induced active acoustic metadevices,the present paradigm may find broad engineering applications,ranging from noise control and audio modulation to sonic camouflage.

关键词： typically conducting artificial