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Thin-Wall Aluminum Die-Casting Technology for Development of Notebook Computer Housing

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Journal of Materials Science & Technology 2008年第1期24卷 65-69页

作者： chang-Seog Kang Jae-Ik Cho chang- Yeol Jeong Se- Weon Choi young-chan kim Korea Institute of Industrial Technology Gwangju Korea

Silicon-based aluminum casting alloys are known to be one of the most widely used alloy systems mainly due to their superior casting characteristics and unique combination of mechanical and physical properties. However,manufacturing of thin-walled aluminum die-casting components,less than 1.0 mm in thickness,is generally known to be very difficult task to achieve aluminum casting alloys with high ***,in this study,the optimal die-casting conditions for producing 297 mm×210 mm×0.7 mm thin-walled aluminum component was examined experimentally by using 2 different gating systems,tangential and split type,and vent ***,computational solidification simulation was also *** results showed that split type gating system was preferable gating design than tangential type gating system at the point of view of soundness of casting and distortion generated after *** was also found that proper vent design was one of the most important factors for producing thin-wall casting components because it was important for the fulfillment of the thin-wall cavity and the minimization of the casting distortion.

关键词： Aluminum Thin-wall die-casting Notebook computer housing Cold chamberdie-casting machine

Die Casting Mold Design of the Thin-walled Aluminum Case by Computational Solidification Simulation

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Journal of Materials Science & Technology 2008年第3期24卷 383-388页

作者： young-chan kim chang-Seog Kang Jae-Ik Cho chang-Yeol Jeong Se-Weon Choi Sung-Kil Hong Korea Institute of Industrial Technology Chonnam National University

Recently, demand for the lightweight alloy in electric/electronic housings has been greatly increased. However, among the lightweight alloys, aluminum alloy thin-walled die casting is problematic because it is quite difficult to achieve sufficient fluidity and feedability to fill the thin cavity as the wall thickness becomes less than 1mm. Therefore, in this study, thin-walled die casting of aluminum （Al-Si-Cu alloy： ALDC 12） in size of notebook computer housing and thickness of 0.8 mm was investigated by solidification simulation （MAGMA soft） and actual casting experiment （Buhler Evolution B 53D）. Three different types of gating design, finger, tangential and split type with 6 vertical runners, were simulated and the results showed that sound thin-walled die casting was possible with tangential and split type gating design because those gates allowed aluminum melt to flow into the thin cavity uniformly and split type gating system was preferable gating design comparing to tangential type gating system at the point of view of soundness of casting and distortion generated after solidification. Also, the solidification simulation agreed well with the actual die-casting and the casting showed no casting defects and distortion.

关键词： Aluminum casting alloy Thin-wall die casting Solidification simulation

Interface properties and phase formation between surface coated SKD61 and aluminum alloys

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中国有色金属学会会刊：英文版 2009年第4期19卷 875-878页

作者： Se-Weon CHOI young-chan kim Se-Hun chanG Ik-Hyun OH Joon-Sik PARK chang-Seog KANG Automotive Components Center Korea Institute of Industrial Technology Division of Advanced Materials Engineering Hanbat National University

The intermediate phase formation and surface protection effects between SKD61 die mold alloys and aluminum alloys were investigated during a simulated die-casting *** surface coatings of SKD61 alloy were carried out via Si pack cementation coatings at 900 ℃ for 10 h and the ε-FeSi phase *** the coated SKD61 alloy was dipped in the liquid aluminum alloy(ALDC12),the surface coated SKD61 alloys showed better surface properties compared with uncoated SKD61 alloys,i.e.,the intermediate phases(FeSiAl compound) were not produced for the coated SKD61 *** coating layer of ε-FeSi served as a diffusion barrier for the formation of FeSiAl compounds.

关键词：表面涂层铝合金接口特性表面合金涂层表面保护合金生产化合物中间相

Dual in-situ observation of tribochemical and morphological evolution of single-layer WS_(2)and multi-layer WS_(2)/C coatings

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Friction 2024年第7期12卷 1580-1598页

作者： Yuzhen LIU Jae-Ho HAN Shusheng XU young chan JUNG Dae-Eun kim State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Department of Mechanical Engineering Yonsei UniversitySeoul03722Republic of Korea Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai Yantai 264000China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Yantai 264000China

The outstanding tribological performance of transition metal dichalcogenides(TMDs)is attributed to their unique sandwich microstructure and low interlayer shear *** advantageous structure allows TMDs to demonstrate exceptional friction reduction ***,the incorporation of TMDs and amorphous carbon(a-C)in multi-layer structures shows excellent potential for further enhancing tribological and anti-oxidation *** carbon,known for its high ductility,chemical inertness,and excellent wear resistance,significantly contributes to the overall performance of these multi-layer *** gain an in-depth understanding of the tribological mechanism and evolution of TMDs’multi-layer coatings,a dual in-situ analysis was carried out using a tribometer equipped with a 3D laser microscope and a Raman *** innovative approach allowed for a comprehensive evolution of the tribological,topographical,and tribochemical characteristics of both single-layer WS_(2)and multi-layer WS_(2)/C coatings in real *** findings from the dual in-situ tribotest revealed distinct failure characteristics between the single-layer WS_(2)coating and the multi-layer WS_(2)/C *** single-layer WS_(2)coating predominantly experienced failure due to mechanical removal,whereas a combination of mechanical removal and tribochemistry primarily influenced the failure of the multi-layer WS_(2)/C *** tribological evolution process of these two coatings can be classified into four stages on the basis of their tribological behavior:the running-in stage,stable friction stage,re-deposition stage,and lubrication failure *** stage represents a distinct phase in the tribological behavior of the coatings and contributes to our understanding of their behavior during sliding.

关键词： In-situ analysis multi-layer coating tribology tribochemistry

Tetradentate Pt(Ⅱ)complex as a singlet exciton sensitizing host for highly efficient green fluorescent organic light-emitting diodes

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Science China Materials 2024年第8期67卷 2618-2627页

作者： Unhyeok Jo Seung chan kim chan Hee Ryu Kang Mun Lee Jae-Min kim Jun Yeob Lee School of Chemical Engineering Sungkyunkwan University2066Seobu-roJangan-guSuwon-siGyeonggi-do 16419Republic of Korea Department of Chemistry Institute for Molecular Science and Fusion TechnologyKangwon National UniversityChuncheonGangwon 24341Republic of Korea Department of Advanced Materials Engineering Chung-Ang University4726Seodong-daeroDaedeok-myeonAnseong-siGyeonggi-do 17546Republic of Korea SKKU Advanced Institute of Nano Technology Sungkyunkwan University2066Seobu-roJangan-guSuwonGyeonggi 16419Republic of Korea SKKU Institute of Energy Science and Technology Sungkyunkwan University2066Seobu-roJangan-guSuwonGyeonggi 16419Republic of Korea

Efficient green fluorescent organic light-emitting diodes were designed with a phosphorescent metal complex as a singlet exciton sensitizing host(SESH)for achieving high efficiency and low efficiency roll-off through exciton and polaron *** Pt(Ⅱ)complex(Pt-Trz)possessing a tetradentate ligand with a bulky blocking group not only suppresses the severe formation of excimer or dimer itself but also transfers radiative excitons to fluorescent dopant *** SESH assisted fluorescence(SESHF)device with Pt-Trz as the host exhibits the maximum external quantum efficiency of 13.3%and a lower efficiency roll-off compared with exciplex host device which is a general approach for harvesting triplet *** exciton dynamics modeling unravels that the SESHF device effectively utilizes triplet excitons in the host by intersystem crossing and resonance energy transfer from the triplet state of the host to the singlet state of the terminal *** quenching rates of the SESHF device are reduced by 11 times for triplet-triplet annihilation and 1.8 times for tripletpolaron annihilation compared with the exciplex device,which demonstrates that Pt-Trz could be a platform to be used as an efficient host for fluorophores.

关键词： singlet annihilation polaron

Construction of a High‑Performance Composite Solid Electrolyte Through In‑Situ Polymerization within a Self‑Supported Porous Garnet Framework

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Nano-Micro Letters 2024年第5期16卷 56-70页

作者： An‑Giang Nguyen Min‑Ho Lee Jaekook kim chan‑Jin Park Department of Materials Science and Engineering Chonnam National University77 Yongbong‑roBuk‑guGwangju 61186South Korea

Composite solid electrolytes(CSEs)have emerged as promising candidates for safe and high-energy–density solid-state lithium metal batteries(SSLMBs).However,concurrently achieving exceptional ionic conductivity and interface compatibility between the electrolyte and electrode presents a significant challenge in the development of high-performance CSEs for *** overcome these challenges,we present a method involving the in-situ polymerization of a monomer within a self-supported porous Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZT)to produce the *** synergy of the continuous conductive LLZT network,well-organized polymer,and their interface can enhance the ionic conductivity of the CSE at room ***,the in-situ polymerization process can also con-struct the integration and compatibility of the solid electrolyte–solid electrode *** synthesized CSE exhibited a high ionic conductivity of 1.117 mS cm^(-1),a significant lithium transference number of 0.627,and exhibited electrochemical stability up to 5.06 V ***/Li+at 30℃.Moreover,the Li|CSE|LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cell delivered a discharge capacity of 105.1 mAh g^(-1) after 400 cycles at 0.5 C and 30℃,corresponding to a capacity retention of 61%.This methodology could be extended to a variety of ceramic,polymer electrolytes,or battery systems,thereby offering a viable strategy to improve the electrochemical properties of CSEs for high-energy–density SSLMBs.

关键词： Scalable tape-casting method Self-supported porous Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12) Composite solid electrolyte LiF-and B-rich interphase layers

Integration of earth-abundant cocatalysts for high-performance photoelectrochemical energy conversion

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Journal of Energy Chemistry 2024年第1期88卷 336-355,I0008页

作者： Joonhee Ma Sang Hyun Ahn Soo young kim Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea School of Chemical Engineering and Materials Science Chung-Ang University84 Heukseok-roDongjak-guSeoul 06974Republic of Korea

Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and *** utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added ***,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical ***,significant research has been conducted to improve the overall conversion efficiency of PEC *** particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy *** review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) *** main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/***,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based *** addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with ***,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.

关键词： Solar energy Photo-electrochemical Water splitting CO_(2)reduction Cocatalysts

In situ infrared, Raman and X-ray spectroscopy for the mechanistic understanding of hydrogen evolution reaction

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Journal of Energy Chemistry 2024年第3期90卷 632-651,I0014页

作者： Andi Haryanto Kyounghoon Jung chan Woo Lee Dong-Wan kim Department of Chemistry Kookmin UniversitySeoul 02707Republic of Korea School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea

Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy *** methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic *** this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the *** addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during *** spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.

关键词： Hydrogen evolution reaction Infrared spectroscopy Raman spectroscopy X-ray absorption spectroscopy Reaction mechanism

Absence of enhancement in a lesion does not preclude primary central nervous system T-cell lymphoma:A case report

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World Journal of Clinical Cases 2024年第2期12卷 374-382页

作者： chan-Seop kim Chi-Hoon Choi Kyung Sik Yi Yook kim Jisun Lee chang Gok Woo young Hun Jeon Department of Radiology Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea Department of Pathology Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea Department of Radiology Seoul National University HosptialSeoul 03080South Korea

BACKGROUND Primary central nervous system lymphoma(PCNSL)is a non-Hodgkin lymphoma that originates in the central nervous system(CNS)and is exclusively limited to the *** most PCNSLs are diffuse large B-cell lymphomas,primary CNS T-cell lymphomas(PCNSTLs)are *** typically demonstrate some degree of enhancement on contrast-enhanced magnetic resonance imaging(MRI).To the best of our knowledge,non-enhancing PCNSTL has not been reported *** SUMMARY A 69-year-old male presented to the neurology department with complaints of mild cognitive impairment and gradual onset of left lower leg weakness over a span of two *** MRI showed asymmetric T2-hyperintense lesions within the *** enhancement was observed on the contrast-enhanced T1 *** initial diagnosis was neuro-Behçet’s *** high-dose steroid therapy,no alterations in the lesions were identified on initial *** patient’s symptoms deteriorated *** MRI performed one month after the initial scan revealed an increased lesion ***,brain biopsy confirmed the diagnosis of *** patient underwent definitive combined ***,the patient developed bacteremia and died of septic shock approximately three months after *** The absence of enhancement in the lesion did not rule out PCNSTL.A biopsy approach is advisable for pathological confirmation.

关键词： Central nervous system neoplasms Non-Hodgkin Lymphoma T-cell Lymphoma Primary central nervous system lymphoma Primary central nervous system T-cell lymphoma Case report