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Ruthenium-lead oxide for acidic oxygen evolution reaction in proton exchange membrane water electrolysis

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Nano Research 2024年第10期17卷 8671-8677页

作者： Feng-Yang Chen Chang Qiu Zhen-Yu Wu Tae-ung Wi YZou Finfrock Haotian Wang Department of Chemical and Biomolecular Engineering Rice UniversityHoustonTX 77005USA Structural Biology Center X-ray Science DivisionArgonne National LaboratoryLemontIL 60439USA Department of Materials Science and NanoEngineering Rice UniversityHoustonTX 77005USA Department of Chemistry Rice UniversityHoustonTX 77005USA

Developing an active and stable anode catalyst for the proton exchange membrane water electrolyzer(PEM-WE)is a critical objective to enhance the economic viability of green hydrogen ***,the expensive iridium-based electrocatalyst remains the sole practical material with industrial-level stability for the acidic oxygen evolution reaction(OER)at the ***-based catalysts have been proposed as more cost-effective alternatives with improved activity,though their stability requires *** current urgent goal is to reduce costs and noble metal loading of the OER catalyst while maintaining robust activity and *** this study,we design a Ru-based OER catalyst incorporating Pb as a supporting *** electrocatalyst exhibits an OER overpotential of 201 mV at 10 mA·cm^(-2),simultaneously reducing Ru noble metal loading by~40%.Normalization of the electrochemically active surface area unveils improved intrinsic activity compared to the pristine RuO_(2) *** a practical stability test in a PEM-WE setup,our developed catalyst sustains stable performance over 300 h without notable degradation,underscoring its potential for future applications as a reliable anodic catalyst.

关键词： electrocatalysis oxygen evolution reaction water splitting proton exchange membrane water electrolyzer

Novel elastomeric spiropyran‑doped poly(dimethylsiloxane)optical waveguide for UV sensing

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Frontiers of Optoelectronics 2024年第3期17卷 1-15页

作者： Camila Aparecida Zimmermann Kof Novignon Amouzou Dipankar Sengupta Aashutosh Kumar Nicole Raymonde Demarquette Bora ung Department of Electrical Engineering École de Technologie SupérieureMontrealQC H3C 1K3Canada Department of Mechanical Engineering École de Technologie SupérieureMontrealQC H3C 1K3Canada

Novel poly(dimethylsiloxane)(PDMS)doped with two diferent spiropyran derivatives(SP)were investigated as potential candidates for the preparation of elastomeric waveguides with UV-dependent optical ***,free-standing flms were prepared and evaluated with respect to their photochromic response to UV ***,reversibility as well as photofatigue and refractive index of the SP-doped PDMS samples were ***,SP-doped PDMS waveguides were fabricated and tested as UV sensors by monitoring changes in the transmitted optical power of a visible laser(633 nm).UV sensing was successfully demonstrated by doping PDMS using one spiropyran derivative whose propagation loss was measured as 1.04 dB/cm at 633 nm,and sensitivity estimated at 115%change in transmitted optical power per unit change in UV *** decay and recovery time constants were measured at 42 and 107 s,respectively,with an average UV saturation dose of 0.4 J/*** prepared waveguides exhibited a reversible and consistent response even under *** sensor parameters can be tailored by varying the waveguide length up to 21 cm,and are afected by white light and temperatures up to 70℃.This work is relevant to elastomeric optics,smart optical materials,and polymer optical waveguide sensors.

关键词： Spiropyrans PDMS Photochromism Polymer optical waveguides UV detection

Neuromodulation of the peripheral nervous system:Bioelectronic technology and prospective developments

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BMEMat(BioMedical Engineering Materials) 2024年第1期2卷 88-114页

作者： Hayoung Song Moohyun Kim Enji Kim Jakyoung Lee Inhea Jeong Kyeonghee Lim Seoung Young Ryu Myoungjae Oh Younhee Kim Jang-ung Park Department of Materials Science and Engineering Yonsei UniversitySeoulSouth Korea Center for Nanomedicine Institute for Basic Science(IBS)SeoulSouth Korea Department of Neurosurgery Yonsei University College of MedicineSeoulSouth Korea Graduate Program of Nano Biomedical Engineering(NanoBME) Advanced Science InstituteYonsei UniversitySeoulSouth Korea

The peripheral nervous system(PNS)is a fascinatingly complex and crucial component of the human body,responsible for transmitting vital signals throughout the body's intricate network of *** efficient functioning is paramount to our health,with any dysfunction often resulting in serious medical conditions,including motor disorders,neurological diseases,and psychiatric *** strides in science and technology have made neuromodulation of the PNS a promising avenue for addressing these health *** involves modifying nerve activity using a range of techniques,such as electrical,chemical,optical,and mechanical *** plays a critical role in this effort,allowing for precise,controlled,and sustained stimulation of the *** paper provides an overview of the PNS,discusses the current state of neuromodulation devices,and presents emerging trends in the field,including advances in wireless power transfer and materials,that are shaping the future of neuromodulation.

关键词： bioelectronics neuromodulation peripheral nervous system

Study on adhesively-bonded surface of tapered double cantilever specimen made of aluminum foam affected with shear force

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Journal of Central South University 2015年第12期22卷 4521-4527页

作者：孙洪鹏 CHO Jae-ung Division of Mechanical Engineering Graduate School Kongju National University Division of Mechanical and Automotive Engineering Kongju National University

Aluminum foam is widely used in diverse areas to minimize the weight and maximize the absorption of shock energy in lightweight structures and various *** presents a number of advantages,such as low density,incombustibility,non-rigidity,excellent energy absorptivity,sound absorptivity and low heat *** aluminum foam with an air cell structure was placed under the TDCB Mode II tensile load by using Landmark equipment manufactured by MTS to examine the shear failure *** angle of the tapered adhesively-bonded surfaces of specimens was designated as a variable,and three models were developed with the inclined angles differing from one another at 6°,8° and 10°.The specimens with the inclined angles of 6°,8° and 10° have the maximum reaction forces of 168 N,194 N when the forced displacements are 6,5 and 4.2 mm *** are three specimens with the inclined angles of 10°,8° and 6° in the order of maximum reaction *** the analysis result,the maximum equivalent stresses of 0.813 MPa and 0.895 MPa happened when the forced displacements of 6 mm and 5 mm proceeded at the models of 6° and 8°,respectively.A simulation was carried out on the basis of finite element method and the experimental *** results of the experiment and the simulation analysis are shown not different from each other ***,only a simulation could be confirmed to be performed in substitution of an experiment,which is costly and time-consuming in order to determine the shearing properties of materials made of aluminum foam with artificial data.

关键词： adhesive displacement force reaction shearing fracture characteristic tapered double cantilever beam(TDCB)

Electrochemical characteristics of phosphorus doped Si-C composite for anode active material of lithium secondary batteries

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中国有色金属学会会刊：英文版 2009年第4期19卷 1018-1022页

作者： Jae-Hyun NOH Kwan-Yo ung LEE Joong-Kee LEE Battery Research Center Korea Institute of Science and Technology Department of Chemical and Biological Engineering Korea University

Phosphorus doped silicon-carbon composite particles were synthesized through a DC arc plasma ***(SiH4) and methane(CH4) were introduced into the reaction chamber as the precursor of silicon and carbon,***(PH3) was used as a phosphorus dopant *** of synthesized particles were carried out by scanning electron microscopy(SEM),X-ray diffractometry(XRD),X-ray photoelectron spectroscopy(XPS) and bulk resistivity *** properties were investigated by cyclic test and electrochemical voltage spectroscopy(EVS).In the experimental range,phosphorus doped silicon-carbon composite electrode exhibits enhanced cycle performance than intrinsic silicon and phosphorus doped *** can be explained that incorporation of carbon into silicon acts as a buffer matrix and phosphorus doping plays an important role to enhance the conductivity of the electrode,which leads to the improvement of the cycle performance of the cell.

关键词：电化学特性磷掺杂负极活性材料磷硅电池材料锂离子 X射线光电子能谱扫描电子显微镜

Carbon Dioxide Concentration and Flux in an Urban Residential Area in Seoul,Korea

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Advances in Atmospheric Sciences 2014年第5期31卷 1101-1112页

作者： Moon-Soo PARK Seung Jin JOO Soon-ung PARK Weather Information Service Engine Center for Atmospheric Science & Earthquake ResearchSeoul 121-835 Korea Center for Atmospheric and Environmental Modeling Seoul 152-775 Korea

The carbon dioxide （CO2） concentrations and fluxes measured at a height of 17.5 m above the ground by a sonic anemometer and an open-path gas analyzer at an urban residential site in Seoul, Korea from February 2011 to January 2012 were analyzed. The annual mean CO2 concentration was found to be 750 mg m-3, with a maximum monthly mean concentration of 827 mg m-3 in January and a minimum value of 679 mg m-3 in August. Meanwhile, the annual mean CO2 flux was found to be 0.45 mg m-2 s-1, with a maximum monthly mean flux of 0.91 mg m-2 s-1 in January and a minimum value of 0.19 mg m-2 s-1 in June. The hourly mean CO2 concentration was found to show a significant diurnal variation; a maximum at 0700-0900 LST and a minimum at 1400-1600 LST, with a large diurnal range in winter and a small one in summer, mainly caused by diurnal changes in mixing height, CO2 flux, and surface complexity. The hourly mean CO2 flux was also found to show a significant diurnal variation, but it showed two maxima at 0700-0900 LST and 2100-2400 LST, and two minima at 1100-1500 LST and 0300-0500 LST, mainly caused by a diurnal pattern in CO2 emissions and sinks from road traffic, domestic heating and cooking by liquefied natural gas use, and the different horizontal distribution of CO2 sources and sinks near the site. Differential advection with respect to wind direction was also found to be a cause of diurnal variations in both the CO2 concentration and flux.

关键词： CO2 concentration CO2 flux liquefied natural gas (LNG) Seoul urban residential area

Effects of Fulfilment of Employer Obligations on Task Performance and Perceived Shared Leadership:The Mediating Role of Fulfilment of Employee Obligations

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Effects of Fulfilment of Employer Obligations on Task Perfor...

作者： IVHONG ung 上海交通大学

学位级别：硕士

Introduction-Psychological contract has been considered as a popular framework to examine and understand various phenomena of the employment relationship within the contemporary organizational ***-The current study examines the psychological contract as a model to explore the reciprocity within the employer-employee exchange ***,I study the reciprocal effects between employer obligations and employee obligations.I hypothesize that employer fulfillment of obligations is positively related to employee fulfillment of *** addition,I hypothesize employer fulfillment of obligations has a positive relationship with task performance,and perceived shared leadership,and specifically,the fulfillment of employee obligations mediates the relationship between the fulfillment of employer obligations and task performance,and perceived shared *** – to study the relationships,a cross-sectional survey of 276 knowledge-intensive employees and 36 of their matched supervisors were retained to test the research hypotheses through the mean,standard deviation,and regression ***-Firstly,I found broad agreement supporting the norm of reciprocity that governs the employer-employee relationship as the results indicated that fulfillment of employer obligations was positively related fulfillment of employee ***,the findings also suggested that fulfillment of employer obligations was positively related to task performance,and perceived shared ***,fulfillment of employee obligations fully mediated the relationship between the fulfillment of employer obligations and task *** of employee obligations also fully mediated the relationship between the fulfillment of employer obligations and perceived shared ***-This study contributed to the understanding of the importance of fulfillment of employer obligations predicting fulfillment of employee obligations w

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Recent advances in electronic devices for monitoring and modulation of brain

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Nano Research 2021年第9期14卷 3070-3095页

作者： Yong Won Kwon Yoon Sun Jun Young-Geun Park Jiuk Jang Jang-ung Park Nano Science Technology Institute Department of Materials Science and EngineeringYonsei UniversitySeoul 03722Republic of Korea Center for Nanomedicine Institute for Basic Science(IBS)Seoul 03722Republic of Korea Graduate Program of Nano Biomedical Engineering(NanoBME) Advanced Science InstituteYonsei UniversitySeoul 03722Republic of Korea

The brain is actuated by billions of neurons with trillions of interconnections that regulate human *** the mechanisms of these systems that induce sensory reactions and respond to disease remains one of the greatest challenges in science,engineering,and *** advances in nanomaterials and nanotechnologies have led to the extensive research of electronic devices for brain interfaces to better understand the neural activities of the brains complex nervous *** development of sensor devices for monitoring the physiological signals of the brain related to traumatic injury status has accompanied by the progress of electronic neural probes in *** addition,these neurological and stereotactic surgical revolutions hold immense potential for clinical analysis of pharmacological systems within cerebral ***,we review the progress of electronic devices interfacing with brain in terms of the materials,fabrication technologies,and device *** activity can be measured and modulated by brain probes based on newly developed nanofabrication ***,in vivo pathological monitoring of the brain and pharmacological assessment has been developed in miniaturized and wireless *** also consider the key challenges and prospects for further development,and explore the future directions emerging in the latest research.

关键词： neural interfaces neural recording neuromodulation intracranial pressure monitoring microfluidic drug delivery

Recognition of walking environments and gait period by surface electromyography

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Frontiers of Information Technology & Electronic Engineering 2019年第3期20卷 342-352页

作者： Seulki KYEONG Wonseok SHIN Minjin YANG ung HEO Ji-rou FENG Jung KIM Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST)

Recognizing and predicting the movement and intention of the wearer in control of an exoskeleton robot is very challenging. It is difficult for exoskeleton robots, which measure and drive human movements, to interact with humans. Therefore, many different types of sensors are needed. When using various sensors, a data design is needed for effective sensing. An electromyographic(EMG) signal can be used to identify intended motion before the actual movement, and the delay time can be shortened via control of the exoskeleton robot. Before using a lower limb exoskeleton to help in walking, the aim of this work is to distinguish the walking environment and gait period using various sensors, including the surface electromyography(sE MG) sensor. For this purpose, a gait experiment was performed on four subjects using the ground reaction force, human–robot interaction force, and position sensors with sEMG sensors. The purpose of this paper is to show progress with the use of sEMG when recognizing walking environments and the gait period with other sensors. For effective data design, we used a combination of sensor types, sEMG sensor locations, and sEMG features. The results obtained using an individual mechanical sensor together with sEMG showed improvement compared to the case of using an individual sensor, and the combination of sEMG and position information showed the best performance in the same number of combinations of three sensors. When four sensor combinations were used, the environment classification accuracy was 96.1%, and the gait period classification accuracy was 97.8%. Vastus medialis(VM) and gastrocnemius(GAS) were the most effective combinations of two muscle types among the five sEMG sensor locations on the legs, and the results were 74.4% in pre-heel contact(preHC) and 71.7% in pre-toe-off(preTO) for environment classification, and 68.0% for gait period classification, when using only the sE MG sensor. The two effective sE MG feature combinations were "me

关键词： Walking environment Gait Period Surface electromyography (sEMG) Exoskeleton