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Production of Integrated Automotive Part in High Pressure Diecasting Process Using Salt Core

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Journal of Rare Earths 2004年第z2期22卷 57-60页

作者： ki-Bae kim Hyun-Kwang Seok Jun-Su kim Advanced Materials Research Center Korea Institute of Science and TechnologyP.O.Box 131CheongryangSeoul130-650Korea Advanced Materials Research CenterKorea Institute of Science and TechnologyP.O.Box 131CheongryangSeoul130-650Korea Research & Development CenterTechnology Union Co.Ltd742-1Paeksok-dongChonan-siChungchongnam-do330-220Korea

A new concept of salt core, a melting temperature of which is lower than the solidus temperature of cast alloy,was introduced to produce an integrated casting part having a complicated inner shape or requiring under-cut in high pressure die casting or squeeze casting process. A salt core, named a fusible core in this paper because the salt core can be easily extracted just as holding at a temperature under a solidus temperature of a casting alloy, was developed and applied to produce a fuel control part for automotive GDI engine in high pressure diecasting machine. A different salt material of a lower melting temperature than that of A1 alloy was mixed with a different ceramic particulate to improve a thermo-physical property of fusible core. The thermo-physical property of the fusible core was measured and a weight faction of the ceramic particulate was optimized. The selected core materials were poured in metallic mold by gravity to produce a fusible core for a fuel control part for automotive GDI engine. The fuel control part, which the fusible core was included inside, was successful to fabricate in a conventional diecasting machine with no melting of fusible core during casting.

关键词： salt core high pressure diecasting casting part for automotive fusible core

Local Meteorological and Synoptic Characteristics of Fogs Formed over Incheon International Airport in the West Coast of Korea

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Advances in Atmospheric Sciences 2010年第4期27卷 761-776页

作者： Chang ki kim Seong Soo YUM Department of Atmospheric Sciences Yonsei University 134 Shinchon-dong Seodaemun-gu Seoul 120-749 Korea

Fogs observed over Incheon international airport （IIA） in the west coast of Korea from January 2002 to August 2006 are classified into categories of coastal fog, cold sea fog, and warm sea fog based on the areal extent of the fogs and the difference between the air temperature （T ） and the SST, i.e., cold sea fog if TSST = T -SST 〉 0~0C and warm sea fog if TSST 〈 0~0C. The numbers of coastal, cold, and warm sea fog cases are 64, 26, and 9. Coastal fogs form most frequently in winter, while cold sea fogs occur mostly in summer and warm sea fogs are observed from January to May but not in November and December. On average the air gets colder by 1.6~0C during the three hours leading up to the coastal fog formation, and an additional cooling of 1.1~0C occurs during the fog. The change in the dew point temperature （T_d） is minimal except during the fog （0.6~0C）. Decreases in T for the cold and warm sea fogs are relatively smaller. The average Td is higher than SST during the cold sea fog periods but this T_d is more than 4~0C higher than that for the corresponding non-fog days, suggesting that cold sea fogs be formed by the cooling of already humid air （i.e., T_d〉SST）. Increases of T_d are significant during the warm sea fog periods （1.4~0C）, implying that effcient moisture supply is essential to warm sea fog formation. Four major synoptic patterns are identified in association with the observed fogs. The most frequent is a north Pacific high that accounts for 38% of cases. Surface or upper inversions are present in 77%, 69%, and 81% of the fog periods for coastal, cold, and warm sea fogs, respectively.

关键词： costal fogs sea fogs west coast of Korea meteorological and synoptic characteristics

Ransomware Classification Framework Using the Behavioral Performance Visualization of Execution Objects

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Computers, Materials & Continua 2022年第8期72卷 3401-3424页

作者： Jun-Seob kim ki-Woong Park Department of Computer and Information Security and Convergence Engineering for Intelligent DroneSejong UniversitySeoul05006Korea

A ransomware attack that interrupted the operation of Colonial Pipeline(a large *** pipeline company),showed that security threats by malware have become serious enough to affect industries and social infrastructure rather than individuals *** agents and characteristics of attacks should be identified,and appropriate strategies should be established accordingly in order to respond to such *** this purpose,the first task that must be performed is malware *** creators are well aware of this and apply various concealment and avoidance techniques,making it difficult to classify *** study focuses on new features and classification techniques to overcome these *** propose a behavioral performance visualization method using utilization patterns of system resources,such as the central processing unit,memory,and input/output,that are commonly used in performance analysis or tuning of *** extracted the usage patterns of the system resources for ransomware to performbehavioral performance *** results of the classification performance evaluation using the visualization results indicate an accuracy of at least 98.94%with a 3.69%loss ***,we designed and implemented a framework to perform the entire process—from data extraction to behavioral performance visualization and classification performance measurement—that is expected to contribute to related studies in the future.

关键词： Behavioral performance visualization ransomware malware classification

Transanal minimally invasive surgery using laparoscopic instruments of the rectum:A review

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World Journal of Gastrointestinal Surgery 2021年第10期13卷 1149-1165页

作者： Myung Jo kim taek-Gu Lee Department of Surgery Chungbuk National University HospitalChungbuk National University College of MedicineCheongju 28644South Korea

Transanal minimally invasive surgery(TAMIS)was first described in 2010 as an alternative to transanal endoscopic microsurgery(TEM).The TAMIS technique can be access to the proximal and mid-rectum for resection of benign and earlystage malignant rectal lesions and also used for noncurative intent surgery of more advanced lesions in patients who are not candidates for radical *** has a shorter learning curve,reduced device setup time,flexibility in instrument use,and versatility in application than ***,TAMIS shows similar results in a view of the operation time,conversion rate,reoperation rate,and complication to *** these reasons,TAMIS is an easily accessible,technically feasible,and cost-effective alternative to ***,TAMIS has enabled the performance of high-quality local excision of rectal lesions by many colorectal *** TAMIS becomes more broadly utilized such as pelvic abscess drainage,rectal stenosis,and treatment of anastomotic dehiscence,the acquisition of appropriate training must be ensured,and the continued assessment and assurance of outcome must be maintained.

关键词： Transanal minimally invasive Rectal cancer Laparoscopic transanal excision Endoscopic resection Minimally invasive surgery Transanal endoscopic microsurgery

Unraveling the potential of 3D bioprinted immunomodulatory materials for regulating macrophage polarization:State-of-the-art in bone and associated tissue regeneration

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Bioactive Materials 2023年第10期28卷 284-310页

作者： Sayan Deb Dutta Tejal V.Patil Keya Ganguly Aayushi Randhawa ki-taek Lim Department of Biosystems Engineering Kangwon National UniversityChuncheon24341Republic of Korea Institute of Forest Science Kangwon National UniversityChuncheon24341Republic of Korea Interdisciplinary Program in Smart Agriculture Kangwon National UniversityChuncheon24341Republic of Korea

Macrophage-assisted immunomodulation is an alternative strategy in tissue engineering, wherein the interplay between pro-inflammatory and anti-inflammatory macrophage cells and body cells determines the fate of healing or inflammation. Although several reports have demonstrated that tissue regeneration depends on spatial and temporal regulation of the biophysical or biochemical microenvironment of the biomaterial, the underlying molecular mechanism behind immunomodulation is still under consideration for developing immunomodulatory scaffolds. Currently, most fabricated immunomodulatory platforms reported in the literature show regenerative capabilities of a particular tissue, for example, endogenous tissue (e.g., bone, muscle, heart, kidney, and lungs) or exogenous tissue (e.g., skin and eye). In this review, we briefly introduced the necessity of the 3D immunomodulatory scaffolds and nanomaterials, focusing on material properties and their interaction with macrophages for general readers. This review also provides a comprehensive summary of macrophage origin and taxonomy, their diverse functions, and various signal transduction pathways during biomaterial-macrophage interaction, which is particularly helpful for material scientists and clinicians for developing next-generation immunomodulatory scaffolds. From a clinical standpoint, we briefly discussed the role of 3D biomaterial scaffolds and/or nanomaterial composites for macrophage-assisted tissue engineering with a special focus on bone and associated tissues. Finally, a summary with expert opinion is presented to address the challenges and future necessity of 3D bioprinted immunomodulatory materials for tissue engineering.

关键词： Macrophage Immunomodulation Biomaterials 3D bioprinting Tissue engineering

Electrochemical and electronic properties of nitrogen doped fullerene and its derivatives for lithium-ion battery applications

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Journal of Energy Chemistry 2018年第2期27卷 528-534页

作者： Parveen Sood ki Chul kim Seung Soon Jang School of Materials Science and Engineering Georgia Institute of Technology Atlanta CA 30332-0245. USA Department of Chemical Engineering Konkuk University Seoul 05029 Republic of Korea Institute for Electronics and Nonotechnology Georgia Institute of Technology Atlanta GA 30332-0245 USA Parker H. Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA 30332-0245 USA

We have studied the redox potentials and electronic properties of C60 and C59N using density functional theory method. It is found that doping C60 with one nitrogen atom results in a slight increase in redox potential. Next, we have also studied C59N functionalized with various redox-active oxygen containing functional groups and strongly electron withdrawing functional groups. It is found that the intrinsic electronic structure of the molecule is the major determinant of the redox potential. Our DFT calculations show that the electron affinity to redox potential of functionalized C59N is correlated with the LUMO of the systems very well. This is the first systematic study on the redox properties and electronic structures of N-doped C60 systems.

关键词： DFT Redox potential C60 Doping Li-ion battery

Liquid crystal-powered Mie resonators for electrically tunable photorealistic color gradients and dark blacks

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Light(Science & Applications) 2022年第6期11卷 1098-1108页

作者： Trevon Badloe Joohoon kim Inki kim Won-Sik kim Wook Sung kim Young-ki kim Junsuk Rho Department of Mechanical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Department of Biophysics Institute of Quantum BiophysicsSungkyunkwan UniversitySuwon 16419Republic of Korea Department of Intelligent Precision Healthcare Convergence Sungkyunkwan UniversitySuwon 16419Republic of Korea Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Department of Electrical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics Pohang 37673Republic of Korea National Institute of Nanomaterials Technology(NINT) Pohang 37673Republic of Korea

Taking inspiration from beautiful colors in nature,structural colors produced from nanostructured metasurfaces have shown great promise as a platform for bright,highly saturated,and high-resolution *** plasmonic and dielectric materials have been employed to produce static colors that fulfil the required criteria for high-performance color printing,however,for practical applications in dynamic situations,a form of tunability is *** of the additive color palette of red,green,and blue enable the expression of further colors beyond the three primary colors,while the simultaneous intensity modulation allows access to the full color ***,we demonstrate an electrically tunable metasurface that can represent saturated red,green,and blue pixels that can be dynamically and continuously controlled between on and off states using liquid *** use this to experimentally realize ultrahigh-resolution color printing,active multicolor cryptographic applications,and tunable pixels toward high-performance full-color reflective displays.

关键词： saturated printing colors

Detection of Graphene Cracks By Electromagnetic Induction,Insensitive to Doping Level

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Computer Modeling in Engineering & Sciences 2019年第8期120卷 351-361页

作者： Taeshik Yoon Sumin Kang Tae Yeob Kang taek-Soo kim Department of Mechanical Engineering KAISTDaejeon 34141Korea Graphene Research Center KAISTDaejeon 34141Korea

Detection of cracks is a great concern in production and operation processes of graphene based devices to ensure uniform ***,we show a detection method for graphene cracks by electromagnetic *** time varying magnetic field leads to induced voltage signals on graphene,and the signals are detected by a *** measured level of induced voltage is correlated with the number of cracks in graphene *** correlation is attributed to the increasing inductive characteristic of defective graphene,and it is verified by electromagnetic simulation and radio frequency ***,we demonstrate that the induced voltage signal is insensitive to the doping level of *** work can potentially lead to the development of a high-throughput and reliable crack inspection technique for mass production of graphene applications.

关键词： Graphene,crack detection inductance electromagnetic induction insensitive to doping

PIR-based data integrity verification method in sensor network

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Journal of Central South University 2014年第10期21卷 3883-3888页

作者： Yong-ki kim Kwangnam Choi Jaesoo kim JungHo Seok Korea Institute of Science and Technology Information 245 DaehangnoYuseong Daejeon 305-806 Korea

Since a sensor node handles wireless communication in data transmission and reception and is installed in poor environment, it is easily exposed to certain attacks such as data transformation and sniffing. Therefore, it is necessary to verify data integrity to properly respond to an adversary's ill-intentioned data modification. In sensor network environment, the data integrity verification method verifies the final data only, requesting multiple communications. An energy-efficient private information retrieval(PIR)-based data integrity verification method is proposed. Because the proposed method verifies the integrity of data between parent and child nodes, it is more efficient than the existing method which verifies data integrity after receiving data from the entire network or in a cluster. Since the number of messages for verification is reduced, in addition, energy could be used more efficiently. Lastly, the excellence of the proposed method is verified through performance evaluation.

关键词： data integrity verification private information retrieval sensor network