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Enhanced third-harmonic generation by manipulating the twist angle of bilayer graphene

Light(Science & Applications) 2021年第2期10卷 176-185页

作者： Seongju Ha nam Hun park Hyeonkyeong Kim Jiseon Shin Jungseok Choi Sungmin park Ji-Yun Moon Kwanbyung Chae Jeil Jung Jae-Hyun Lee Youngdong Yoo Ji-Yong park Kwang Jun Ahn Dong-Il Yeom Department of Energy Systems Research Ajou University206 Worldcup-roYeongtong-guSuwon 16499Republic of Korea Korea Research Institute of Standards and Science Daejeon 34113Republic of Korea Department of Physics University of Seoul163 SiripdaeroDongdaemun-guSeoul 02504Republic of Korea Department of Smart Cities University of Seoul163 SiripdaeroDongdaemun-guSeoul 02504Republic of Korea Department of Materials Science and Engineering Ajou University206 Worldcup-roYeongtong-guSuwon 16499Republic of Korea Department of Chemistry Ajou University206 Worldcup-roYeongtong-guSuwon 16499Republic of Korea Department of Physics Ajou University206 Worldcup-roYeongtong-guSuwon 16499Republic of Korea

Twisted bilayer graphene(tBLG)has received substantial attention in various research fields due to its unconventional physical properties originating from Moire *** electronic band structure in tBLG modified by interlayer interactions enables the emergence of low-energy van Hove singularities in the density of states,allowing the observation of intriguing features such as increased optical conductivity and photocurrent at visible or near-infrared ***,we show that the third-order optical nonlinearity can be considerably modified depending on the stacking angle in *** third-harmonic generation(THG)efficiency is found to significantly increase when the energy gap at the van Hove singularity matches the three-photon resonance of incident *** study on electrically tuneable optical nonlinearity reveals that the gate-controlled THG enhancement varies with the twist angle in tBLG,resulting in a THG enhanced up to 60 times compared to neutral monolayer *** results prove that the twist angle opens up a new way to control and increase the optical *** tBLG,,suggesting rotation-induced tuneable nonlinear optics in stacked two-dimensional material systems.

关键词： twist angle harmonic

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4-Hydroxycinnamic acid attenuates neuronal cell death by inducing expression of plasma membrane redox enzymes and improving mitochondrial functions

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Food Science and Human Wellness 2023年第4期12卷 1287-1299页

作者： Sujin park YoonA Kim Jaewang Lee Hyunsoo Seo Sang-Jip nam Dong-Gyu Jo Dong-Hoon Hyun Department of Life Science Ewha Womans UniversitySeoul 03760South Korea Department of Chemistry and Nano Science Ewha Womans UniversitySeoul 03760South Korea School of Pharmacy Sungkyunkwan UniversitySuwon 16419South Korea

Many approaches to neurodegenerative diseases that focus on amyloid-βclearance and gene therapy have not been *** therapeutic applications focus on enhancing neuronal cell survival during the pathogenesis of neurodegenerative diseases,including mitochondrial *** membrane(PM)redox enzymes are crucial in maintaining cellular physiology and redox homeostasis in response to mitochondrial *** phytochemicals are known to induce the expression of detoxifying enzymes under stress *** this study,mechanisms of neuroprotective effects of 4-hydroxycinnamic acid(HCA)were examined by analyzing cell survival,levels of abnormal proteins,and mitochondrial functions in two different neuronal *** protected two neuronal cells exhibited high expression of PM redox enzymes and the consequent increase in the NAD^(+)/NADH *** cultured with HCA showed delayed apoptosis and decreased oxidative/nitrative damage accompanied by decreased ROS production in the *** increased the mitochondrial complexes I and II activities and ATP ***,HCA increased mitochondrial fusion and decreased mitochondrial ***,HCA maintains redox homeostasis and energy metabolism under oxidative/metabolic stress *** findings suggest that HCA could be a promising therapeutic approach for neurodegenerative diseases.

关键词： NADH-quinone oxidoreductase 1(NQO1) Cytochrome b5 reductase 4-Hydroxycinnamic acid Neuroprotection Improved mitochondrial functions

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Room-temperature sputtered electrocatalyst WSe2 nanomaterials for hydrogen evolution reaction

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Journal of Energy Chemistry 2020年第8期29卷 107-111,I0004页

作者： Jae Hyeon nam Myeong Je Jang Hye Yeon Jang Woojin park Xiaolei Wang Sung Mook Choi Byungjin Cho Department of Advanced Material Engineering Chungbuk National UniversityChungdae-ro 1Seowon-GuCheongjuChungbuk 28644Republic of Korea Surface Technology Department Korea Institute of Materials Science797 ChangwonDaeroSungsan-guChangwon 51508Republic of Korea Advanced Materials Engineering Korea University of Science and Technology(UST)217 Gajeong-roYuseong-guDaejeon 34113Republic of Korea Department of Chemical and Materials Engineering University of Alberta9211116 Street NWEdmontonAlberta T6C 1H9Canada

The low-temperature physical vapor deposition process of atomically thin two-dimensional transition metal dichalcogenide(2D TMD) has been gaining attention owing to the cost-effective production of diverse electrochemical catalysts for hydrogen evolution reaction(HER) applications. We, herein, propose a simple route toward the cost-effective physical vapor deposition process of 2D WSe2 layered nanofilms as HER electrochemical catalysts using RF magnetron sputtering at room temperature(<27℃). By controlling the variable sputtering parameters, such as RF power and deposition time, the loading amount and electrochemical surface area(ECSA) of WSe2 films deposited on carbon paper can be carefully determined. The surface of the sputtered WSe2 films are partially oxidized, which may cause spherical-shaped particles. Regardless of the loading amount of WSe2, Tafel slopes of WSe2 electrodes in the HER test are narrowly distributed to be ~120–138 mV dec-1, which indicates the excellent reproducibility of intrinsic catalytic activity. By considering the trade-off between the loading amount and ECSA, the best HER performance is clearly observed in the 200 W-15 min sample with an overpotential of 220 mV at a current density of 10 mA cm-2. Such a simple sputtering method at low temperature can be easily expanded to other 2D TMD electrochemical catalysts, promising potentially practical electrocatalysts.

关键词： Two dimensional nanomaterials Sputtering WSe2 nanofilm Electrocatalyst Hydrogen evolution reaction

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Neuroprotective Effect of Chunghyuldan(Qing Xue Dan)on Hypoxia-Reoxygenation Induced Damage of Neuroblastoma 2a Cell Lines

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Chinese Journal of Integrative Medicine 2013年第12期19卷 940-944页

作者： Chang-nam Ko In-Seo park Seong-Uk park Woo-Sang Jung Sang-Kwan Moon Jung-Mi park Chulhun Kang Ki-Ho Cho Department of Cardiology and Neurology Diseases College of Korean MedicineKyung Hee University Department of Medical Science Graduate School of East-West Medical ScienceKyung Hee University

Objectives： Chunghyuldan （CHD）, a combinatorial drug that has anti-hyperlipidemic and anti inflammatory activities, has been shown to reduce infarct volume in a focal ischemia-reperfusion rat model. To explore the molecular basis of CHD＇s neuroprotective effect, we examined whether CHD shows a cell-protective activity and has a regulatory effect on Bax and/or B-cell leukemia/lymphoma 2 （Bcl-2） expression in mouse neuroblastoma 2a （N2a） cells subjected to hypoxia-reoxygenation （H/R）. Methods： In order to evaluate the effects of CHD on the cytotoxicity induced from hypoxia or H/R condition, lactate dehydrogenase （LDH） assay was performed. To explore whether the suppression of neural damage when pre-treated with CHD is associated with its anti-apoptotic effect, the CHD effect on the expression of Bcl-2 and Bax was analyzed by Western blotting analysis. Results： Cytotoxicity of N2a cell line was slightly increased in 42 h hypoxia condition and dramatically increased under the H/R condition. CHD treatment markedly decreased the cytotoxicity in both conditions （P〈0.01, P〈0.05）. H/R markedly increased the expression of the pro-apoptotic protein, Bax, but slightly increased the expression of the anti-apoptotic protein, Bcl-2, compared with the normoxia or hypoxia group. CHD significantly decreased Bax expression （P〈0.01） and slightly decreased Bcl-2 expression （P〉0.05）, resulted in a reduction of Bax/Bcl-2 ratio in N2a cells subjected to H/R. Conclusion： CHD has neuroprotective effect in N2a cells subjected to H/R, which might be derived at least in part from its ability to decrease the expression of the pro-apoptotic protein, Bax.

关键词： apoptosis stroke Chunghyuldan herbal

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STUDY ON DRILLING CHARACTERISTICS AND MECHANICAL PROPERTIES OF CFRP COMPOSITES

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Acta Mechanica Solida Sinica 2008年第4期21卷 364-368页

作者： Seung-Chul Lee Seong-Taek Jeong Jong-nam park Sun-Jin Kim Gyu-Jae Cho Department of Mechanical Engineering Chosun UniversityGraduate SchoolGwangjuKorea Small Business Corporation GwangjuKorea Department of Computer Mechanic Chosun College of Science & TechnologyGwangjuKorea Department of Fire Safety Management Seokang CollegyGwangjuKorea Department of Mechanical Engineering Chosun UniversityGwangjuKorea

Stacking plates of CFRP composite materials are increasingly used because of their unique characteristics. However, unlike other materials used in metallurgy they have a disadvantage of uneven quality and anisotropy when combined with other composites. Hence, specimens of CFRP stacking plates are manufactured by changing orientation angles throughout three quasiisotropic plies （0°/45°/90°/-45°）68, （03°/453°/903°/-453°）2s, and （06°/456°/906°/-456°）s and throughout three cross plies （0°/90°/0°/90°）68, （03 °/903 °/03°/903°）2s, and （06 °/906 °/06°/906°）8 In this study 3-point bending tests and transverse bending tests have been carried out in order to find out mechanical characteristics according to orientation angles by stacking in 6 different types along with the change of stacking composition method of a CFRP composite.

关键词： composite materials stacking plates

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Laser-induced plasma generated by a 532nm pulsed laser in bulk water:unexpected line-intensity variation with water temperature and the possible underlying physics

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Plasma Science and Technology 2020年第7期22卷 65-74页

作者： Sandeep KUMARI Jeong park Sang-Ho nam Song_Hee HAN Yonghoon LEE Department of Chemistry Mokpo National UniversityJeonnam 58554Republic of Korea Division of Navigation Science Mokpo National Maritime UniversityJeonnam 58628Republic of Korea

The effect of the matrix temperature on laser-induced plasma generated in bulk water by using a532 nm pulsed laser beam has been *** Ⅰ and Ⅱ emission line intensities were recorded for an aqueous solution of CaCl2 in the temperature range of 7℃-70℃.The emission line intensities did not follow the matrix temperature in our *** intensities were observed at ~18℃ for both ***,a possible mechanism responsible for the observed variation in intensity is suggested,in which laser-produced bubbles play important *** formation is essential to ignite plasma in the liquid and more feasible at the higher liquid ***,the abundant bubbles at the higher temperature can scatter the incident laser beam more effectively to decrease the energy delivered for the laser-induced ***,these two roles have effects on the optical emission intensities in opposite *** validity of the suggested mechanism is discussed based on the plasma temperature,temperature dependence of the refractive index of water,plasma electron density,scattered light intensity,and plasma ignition threshold *** result indicates that the temperature of the liquid is also an important parameter to be considered in the laser-induced breakdown spectroscopy analysis of bulk liquid samples and its application in deep-sea exploration.

关键词： laser-induced breakdown spectroscopy liquid analysis laser-produced bubble

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A new hemostatic clip for endoscopic surgery that can maintain blood flow after clipping

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World Journal of Gastroenterology 2014年第5期20卷 1325-1331页

作者： Kyoung Won nam Sang Bong Lee In Young Kim Kwang Gi Kim Sang Jae park Department of Biomedical Engineering Hanyang University Biomedical Engineering Branch National Cancer Center Center for Liver Cancer National Cancer Center

AIM: To develop a new hemostatic device for endoscopic surgery that can control the bleeding without completely occluding the bleeding vessel.

关键词： Vessel bleeding Hemostasis Hemostatic clip Laparoscopic surgery Endoscopic surgery

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Overexpression of S100A4 is closely associated with progression of colorectal cancer

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World Journal of Gastroenterology 2005年第31期11卷 4852-4856页

作者： Yong-Gu Cho Chang-Jae Kim Suk-Woo nam Shin-Hee Yoon Sug-Hyung Lee nam-Jin Yoo Jung-Young Lee Won-Sang park Department of Pathology Department of Physiology

AIM： To investigate whether S100A4 played an important role in the development or progression of colorectal cancer. METHODS： A total of 124 colorectal adenocarcinoma tissue specimens were analyzed by immunohistochemistry for the expression of S100A4 protein and subsequently investigated for the gene mutations in the coding region of S100A4 gene. The specimens were collected over a 3-year period in the laboratories at our large teaching hospital in Seoul, Republic of Korea. RESULTS： Normal colonic epithelium either failed to express or showed focal weak expression of S100A4. Moderate to strong cytoplasmic expression of S100A4 was seen in 69 （55.6%） of the 124 colorectal carcinoma tissue specimens. S100A4 expression was detected in 43 （69.4%） of 62 specimens with lymph node metastasis. Statistically, overexpression of S100A4 was significantly associated with Dukes＇ stage and lymph node metastasis. Nuclear staining was also observed in 24 （19.4%） of 124 samples and closely associated with Dukes＇ stage. However, there was no significant correlation between overexpression of S100A4 and other investigated clinico-pathologic parameters, including tumor localization, tumor size, and survival period. In mutational analysis, no gene mutation was found in the analyzed genomic area of colorectal cancer. CONCLUSION： Overexpression of S100A4 may be closely related with the aggressiveness of colorectal carcinoma.

关键词： S100A4 Mutation Immunohistochemistry Colorectal cancer Tumor stage

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Fundamental principles and development of proximity-field nanopatterning toward advanced 3D nanofabrication

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Nano Research 2021年第9期14卷 2965-2980页

作者： Sang-Hyeon nam Gayea Hyun Donghwi Cho Seonggon Han Gwangmin Bae Haomin Chen Kisun Kim Youngjin Ham Junyong park Seokwoo Jeon Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina School of Materials Science and Engineering Kumoh National Institute of TechnologyGumiGyeongbuk 39177Republic of Korea Department of Energy Engineering Convergence Kumoh National Institute of TechnologyGumiGyeongbuk 39177Republic of Korea KAIST Institute for NanoCentury(KINC) KAISTDaejeon 34141Republic of Korea

Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic *** outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical *** the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter *** the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic *** conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several *** merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase *** this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target ***,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.

关键词： proximity-field nanopatterning three-dimensional(3D)nanostructures phase mask interference lithography

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Prevalence of premature ejaculation in young and middle-aged men in Korea： a multicenter intemet-based survey from the Korean Andrological Society

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Asian Journal of Andrology 2010年第6期12卷 880-889页

作者： Hyun Jun park Jong Kwan park Kwangsung park Sung Won Lee Sae-Woong Kim Dae Yul Yang DU Geon Moon Kweon-Sik Min Ki-Hak Moon Sang-Kuk Yang Jae Seog Hyun nam Cheol park Deparment of Urology Pusan National University School of medicine Busan 602739 Korea Deparment of Urology Chonbuk National University Medical School Jeonju 561712 Korea Deparment of Urology Chonnam National University Medical School Gwangju 501746 Korea Deparment of Urology Sungkyunkwan Univer＆ty School of Medicine Seou1135 710 Korea Deparment of Urology Catholic University College of Medicine Seoul 137701 Korea Deparment of Urology Hallym University College of Medicine Seoul 13 7701 Korea Deparment of Urology Korea University College of Medicine Seoul 152703 Korea Deparment of Urology lnje University College of Medicine Busan 614735 Korea Deparment of Urology Yeungnam University College of Medicine Daegu 705717 Korea Deparment of Urology Konkuk University School of Medicine Chungju 380704 Korea Deparment of Urology Gyeongsang National University School of Medicine Jinju 660702 Korea

In this study, we aimed to investigate the prevalence and perception of premature ejaculation （PE） in young and middle-aged Korean men. The study was conducted using an Internet-assisted questionnaire. A total of 2 037 Korean male adults, aged 20 years or older, were randomly sampled based on age and residency. The questionnaire developed by the PE Study Group of the Korean Andrological Society includes four categories （overall sexual function, symptoms, distress and treatment） with a total of 16 questions. For each question, symptoms were evaluated by a scale ranging from 0 to 10. Intravaginal ejaculation latency time was ‘5-10 min＇ in 38.6%, followed by ‘longer than 10 min＇ in 2919%, ‘2-5 min＇ in 23.6%, ‘1-2 min＇ in 5.4% and ‘shorter than 1 min＇ in 2.5%. In our series, 27.5% of respondents reported having PE. Control over ejaculation within a recent 3-month period was 6.2 points on average. Respondent complaints of PE-related stress averaged 7.1 points and stress-related complaints from sexual partners averaged 7.1 points. The effect of PE on sexual life was 6.8 points. Of the respondents determined as having PE, 42.6% responded that they were inclined to receive treatment. Results from this study suggest that the prevalence of PE diagnosed by the respondent on his own was approximately 27.5% in young and middle-aged men in Korea. PE-related stress had a significant effect on the stress, sexual activity and quality of life of the respondent and his sexual partner.

关键词： epidemiology premature ejaculation questionnaire sexual dysfunction

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