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Highly efficient reduction of aqueous Cr(VI) with novel ZnO/SnS nanocomposites through the piezoelectric effect

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Journal of Environmental Sciences 2022年第8期34卷 57-66页

作者： Hao Sun soo-Jin park Department of Chemistry and Chemical Engineering Inha UniversityIncheon 22212South Korea

In this work, novel ZnO/SnS nanocomposites were successfully synthesized via a hydrothermal approach, which is developed for piezoelectric catalytic reduction of hexavalent chromium(Cr(VI)) in an aqueous solution. The constructed ZnO/SnS nanocomposites exhibited higher catalytic efficiency for Cr(VI) reduction under a mechanical force(e.g., ultrasonic vibration) compared to pristine ZnO and SnS. In particular, the ZnO/SnS(with 30 wt.% of SnS) heterojunctions revealed an optimal degradation activity among all the prepared samples, which completely removed the Cr(VI)(20 mg/L) solution within 35 min. Moreover, the piezoelectric catalytic activity of ZnO/SnS remained stable after four consecutive cycling experiments. The results of the morphology observations indicated that the SnS nanoparticles adhere to the surface of the ZnO nanorods. The improved piezoelectric catalytic performance of the ZnO/SnS heterojunctions can be attributed to the formation of an intimate interfacial between ZnO and SnS, which effectively inhibits the electron-hole recombination and speeds up the rate of charge transfer. The study reveals a new design of ZnO/SnS heterojunctions as a high-performance and eco-friendly piezoelectric catalyst and provides a promising strategy for addressing environmental problems and energy crises.

关键词： Cr(VI)reduction ZnO/SnS Piezoelectric effect

Biomass-derived bifunctional electrocatalysts for oxygen reduction and evolution reaction: A review

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Journal of Energy Chemistry 2022年第2期31卷 149-172页

作者： Satpal Singh Sekhon Jaeyoung Lee Jin-soo park Future Environment and Energy Research Institute Sangmyung UniversityCheonan 31066Republic of Korea Department of Physics Guru Nanak Dev UniversityAmritsar 143005India Ertl Center for Electrochemistry and Catalysis Gwangju Institute of Science and Technology123 Cheomdangwagi-roBuk-guGwangju 61005Republic of Korea Department of Green Chemical Engineering College of EngineeringSangmyung UniversityCheonan 31066Republic of Korea

Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy ***,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance to their scalable production,whereas scarce and costly Pt and Ir/Ru-based catalysts with the highest electrocatalytic activity are commercially *** good ORR catalysts are not always efficient for OER and vice versa,so bifunctional catalysts on which OER and ORR occurs on the same electrode are very *** catalysts based on heteroatom-doped carbon nanomaterials,though showed good electrocatalytic activity yet their high cost and complex synthesis is not viable for scalable *** overcome these drawbacks,biomass-derived heteroatom-doped porous carbons have recently emerged as low-cost,earth-abundant,renewable and sustainable environment-friendly materials for bifunctional oxygen *** tunable morphology,mesoporous structure and high concentration of catalytic active sites of these materials due to heteroatom(N)-doping could further enhance their ORR and OER activity,along with tolerance to methanol crossover and good ***,biomassderived heteroatom-doped porous carbons with large surface area,rich edge defects,numerous micropores and thin 2 D nanoarchitecture could be suitable as efficient bifunctional oxygen *** the present article,synthesis,N-doping,ORR/OER mechanism and electrocatalytic performance of biomassderived bifunctional catalysts has been *** selected biomass(chitin,eggs,euonymus japonicas,tobacco,lysine and plant residue)except wood,act as both C and N precursor,resulting in N selfdoping of porous carbons that avoids the use of toxic chemicals,thus making the synthesis a facile and environment-friendly green *** synthetic strategy could be further optimized to develop future biomass-based N self-doped porous carbons as metal-free high performance bifunctional oxy

关键词： Bifunctional catalysts Biomass ORR OER N-doping Porous carbons

Amine functionalization on thermal and mechanical behaviors of graphite nanofibers-loaded epoxy composites

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Journal of Materials Science & Technology 2023年第20期151卷 80-88页

作者： Seong-Hwang Kim Sang-Jin park Seul-Yi Lee soo-Jin park Department of Chemistry Inha University100 InharoIncheon 22212the Republic of Korea

With the growing demand for faster and more powerful computing,effective heat dissipation is essential to ensure the longevity,reliability,and high performance of electronic *** the field of modern electronic packaging materials,there is a great need for graphitic material-loaded polymeric composites(GPCs)with excellent thermal ***,the enhancement efficiency of GPCs is hindered by the agglomeration of fillers and the interfacial thermal resistance caused by the lack of continuous thermally conductive pathways between the filler and *** the interfaces between filler and matrix is of great importance in optimizing the performances of ***,we fabricated graphite nanofibers(GNF)-loaded nanocomposites using acid-functionalized GNF(AGNF)and acidtetraethylenepentamine-functionalized(TGNF)as a filler and epoxy resin as a matrix with different GNF loading contents to explore the interfacial properties of the *** optimal GNF loading for AGNF was 0.5 wt.%,while the TGNF showed 0.75 wt.%.The highest thermal conductivity(0.51 W m^(−1) K^(−1))and fracture toughness(25.8 MPa m^(1/2))values were found in the TGNF-loaded nanocomposites with a fraction of 0.75 wt.%,representing enhancements of∼145%and∼400%,respectively,compared to those of neat *** experimental data presented herein demonstrate that the interfacial properties play a significant role in enhancing the thermal and mechanical performances of the *** present approach is expected to serve as a valuable tool in the design of conductive polymeric nanocomposites for further practical applications,such as thermal interface materials and packaging of high-power electric devices.

关键词： Graphite nanofiber Nanocomposites Interfacial interaction Thermal conductivity Fracture resistance

Remarkably slow corrosion rate of high-purity Mg microalloyed with 0.05wt% Sc

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Journal of Magnesium and Alloys 2023年第3期11卷 991-997页

作者： soo-Min Baek Jeong-Ki Kim Du-Won Min Sung soo park Department of Materials Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea

We report that the corrosion resistance of Mg is significantly improved by adding 0.05wt%*** rates evaluated from weight loss values after room-temperature immersion in 0.6 M NaCl solution for two weeks were 0.27 and 4.0 mm y^(-1)for the high-purity Mg samples with and without microalloyed 0.05wt%Sc,*** beneficial effect of Sc microalloying on the corrosion resistance of Mg is discussed in connection with Sc-induced microstructural modifications.

关键词： Magnesium Microalloying Intermetallic phase Microgalvanic corrosion

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

Companion diagnostics for the targeted therapy of gastric cancer

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World Journal of Gastroenterology 2015年第39期21卷 10948-10955页

作者： Changhoon Yoo Young soo park Departments of Oncology Asan Medical Center University of Ulsan College of Medicine Department of Pathology Asan Medical Center University of Ulsan College of Medicine

Gastric cancer is the fourth most common type ofcancer and represents a major cause of cancer-related deaths worldwide. With recent biomedical advances in our understanding of the molecular characteristics of gastric cancer, many genetic alterations have been identified as potential targets for its treatment. Multiple novel agents are currently under development as the demand for active agents that improve the survival of gastric cancer patients constantly increases. Based on lessons from previous trials of targeted agents, it is now widely accepted that the establishment of an optimal diagnostic test to select molecularly defined patients is of equal importance to the development of active agents against targetable genetic alterations. Herein, we highlight the current status and future perspectives of companion diagnostics in the treatment of gastric cancer.

关键词： Companion diagnostics gastric cancer human epiderm

Steam activation of Fe-N-C catalyst for advanced power performance of alkaline hydrazine fuel cells

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Journal of Energy Chemistry 2022年第1期31卷 276-285,I0008页

作者： sooan Bae Jihyeon park Yuna Hwang Jin-soo park Jaeyoung Lee Beomgyun Jeong Research Center for Materials Analysis Korea Basic Science Institute169-14&Gwahak-roDaejeon 34133Republic of Korea School of Earth Sciences and Environmental Engineering Gwangju Institute of Science and Technology123 Cheomdangwagi-ro.Buk-guGwangju 61005Republic of Korea Department of Green Chemical Engineering Sangmyung University31 Sangmyungdae-gilDongnam-gu.CheonanChungnam Province 31066Republic of Korea Ertl Center for Electrochemistry and Catalysis Gwangju Institute of Science and Technology123 Cheomdangwagi-roBuk-giiGwangju 61005Republic of Korea

Alkaline hydrazine liquid fuel cells(AHFC) have been highlighted in terms of high power performance with non-precious metal *** Fe-N-C is a promising non-Pt electrocatalyst for oxygen reduction reaction(ORR),the surface density of the active site is very low and the catalyst layer should be thick to acquire the necessary number of catalytic active *** this thick catalyst layer,it is important to have an optimum pore structure for effective reactant conveyance to active sites and an interface structure for faster charge ***,we prepare a Fe-N-C catalyst with magnetite particles and hierarchical pore structure by steam *** steam activation process significantly improves the power performance of the AHFC as indicated by the lower IR and activation voltage *** on a systematic characterization,we found that hierarchical pore structures improve the catalyst utilization efficiency of the AHFCs,and magnetite nanoparticles act as surface modifiers to reduce the interracial resistance between the electrode and the ion-exchange membrane.

关键词： Alkaline hydrazine fuel cell Oxygen reduction reaction Electrocatalyst Steam activation Ohmic loss Interfacial resistance Surface modifier

Sensitivity analysis for axis rotation diagrid structural systems according to brace angle changes

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 783-791页

作者： Jae-Kwang Yang Long-Yang Li Sung-soo park Department of Architectural Engineering Pusan National UniversityKorea Department of Architectural Engineering Pusan National UniversityDoctor of EngineeringKorea

General regular shaped diagrid structures can express diverse shapes because braces are installed along the exterior faces of the structures and the structures have no columns. However, since irregular shaped structures have diverse variables, studies to assess behaviors resulting from various variables are continuously required to supplement the imperfections related to such variables. In the present study, materials elastic modulus and yield strength were selected as variables for strength that would be applied to diagrid structural systems in the form of Twisters among the irregular shaped buildings classified by Vollers and that affect the structural design of these structural systems. The purpose of this study is to conduct sensitivity analysis for axial rotation diagrid structural systems according to changes in brace angles in order to identify the design variables that have relatively larger effects and the tendencies of the sensitivity of the structures according to changes in brace angles and axial rotation angles.

关键词： sensitivity analysis axial rotation-diagrid structure lateral behaviors

Microstructure and corrosion resistance of a Mg2Sn-dispersed Mg alloy subjected to pulsed electron beam treatment

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Journal of Magnesium and Alloys 2020年第2期8卷 345-351页

作者： Daseul Lee Beomcheol Kim soo-Min Baek Jisoo Kim Hyung Wook park Jung Gu Lee Sung soo park School of Materials Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea School of Mechanical Aerospace and Nuclear EngineeringUlsan National Institute of Science and TechnologyUlsan 44919Republic of Korea School of Materials Science and Engineering University of UlsanUlsan 44610Republic of Korea

We report that the corrosion resistance of a Mg-Sn-based alloy with MgzSn precipitates can be considerably improved by surface modification using pulsed electron beam *** alloy subjected to a pulse electron beam treatment showed a modified surface layer with a thickness of〜12 μm,appearing more resistant to corrosion attack than the bare surface of the *** 0.6 M NaCl solution,the alloys with and without the surface modification exhibited average corrosion rates of 4.3 and 8.1 mm y^-1,*** improved corrosion resistance was attributed to reduced cathodic activation,resulting from the surficial reduction of relatively noble Mg2Sn precipitates.

关键词： Magnesium alloy Mg2Sn Intermetallic compound Pulsed electron beam treatment Corrosion