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1.45 GPa ultrastrong cryogenic strength with superior impact toughness in the in-situ nano oxide reinforced CrMnFeCoNi high-entropy alloy matrix nanocomposite manufactured by laser powder bed fusion

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Journal of Materials Science & Technology 2022年第2期97卷 10-19页

作者： Young-Kyun kim min-Chul kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea Korea Atomic Energy Research Institute(KAERI) Daejeon 34057Republic of Korea

CrMnFeCoNi high-entropy alloys(HEAs)exhibit an excellent combination of tensile strength and ductility at cryogenic *** study led to the introduction of a new method for the development of high-performance CrMnFeCoNi HEAs at cryogenic temperatures by jointly utilizing additive manufacturing(AM)and the addition of interstitial *** interstitial oxygen present in the powder feedstock was transformed into beneficial nano-sized oxides during AM *** HEA nanocomposite fabricated using laser powder bed fusion(L-PBF)not only contains heterogeneous grains and substructures but also a high number density of nano-sized *** tensile results revealed that the L-PBF HEA nanocomposite has superior yield strengths of 0.77 GPa and 1.15 GPa,and tensile strengths of 0.92 GPa and 1.45 GPa at 298 K and 77 K,*** addition,the Charpy impact energies of the samples tested at 298 K and 77 K were measured as 176.2 J and 103.7 J,*** results indicate that the L-PBF HEA nanocomposite successfully overcomes the well-known strength-toughness *** tensile deformation microstructure contained a relatively large number of deformation twins(DTs)at cryogenic temperature,a possible consequence of the decrease in the stacking fault energy with decreasing *** the other hand,cracks were found to propagate along the grain boundaries at room temperature,whereas a transgranular crack was observed at cryogenic temperature in the specimens fractured as a result of the Charpy impact.

关键词： Laser powder bed fusion High-entropy alloy matrix nanocomposite Nano-oxide:cryogenic Tensile Impact toughness

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Densification simulation of compacted Al powders using multi-particle finite element method

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中国有色金属学会会刊：英文版 2009年第B09期19卷 68-75页

作者： Kyung-Hun LEE Jung-min LEE Byung-min kim School of Mechanical Engineering Pu san National University

The powder compaction simulations were performed to demonstrate deformation behavior of particles and estimate the effect of different punch speeds and particle diameters on the relative density of powder by a multi-particle finite element model(MPFEM). Individual particle discretized with a finite element mesh allows for a full description of the contact mechanics. In order to verify the reliability of compaction simulation by MPFEM, the compaction tests of porous aluminum with average particle size of 20 μm and 3 μm were performed at different ram speeds of 5, 15, 30 and 60 mm/min by MTS servo-hydraulic tester. The results show that the slow ram speed is of great advantage for powder densification in low compaction force due to sufficient particle rearrangement and compaction force increases with decrease in average particle size of aluminum.

关键词：粉末压实粉末粒子多孔铝有限元法模拟致密化平均粒径有限元模型

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Some Theorems on Leibniz n-Algebras from the Category U_(n)(Lb)

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Algebra Colloquium 2021年第1期28卷 155-168页

作者： min Soo kim Rustam Turdibaev Vanderbilt University NashvilleTN 37235USA V.I.Romanovskiy Institute of Mathematics Uzbekistan Academy of SciencesUniversity Street 4bTashkent 100174Uzbekistan AKFA University 1st Deadlock 10Kukcha DarvozaTashkent 100095Uzbekistan

We study the Leibniz n-algebra U_(n)(L),whose multiplication is defined via the bracket of a Leibniz algebra L as[x1,…,xn]=[x1,[…,[xn−2,[xn−1,xn]]…]].We show that U_(n)(L)is simple if and only if L is a simple Lie *** analog of Levi's theorem for Leibniz algebras in U_(n)(Lb)is established and it is proven that the Leibniz n-kernel of U_(n)(L)for any semisimple Leibniz algebra L is the n-algebra U_(n)(L).

关键词： Leibniz n-algebra Leibniz n-kernel simple Leibniz n-algebra Levi decomposition

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Detecting IoT Botnet in 5G Core Network Using Machine Learning

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Computers, Materials & Continua 2022年第9期72卷 4467-4488页

作者： Ye-Eun kim min-Gyu kim Hwankuk kim Department of Electronics Information and System Engineering Sangmyung UniversityCheonan-siKorea Department of Information Security Engineering Sangmyung UniversityCheonan-siKorea

As Internet of Things(IoT)devices with security issues are connected to 5G mobile networks,the importance of IoT Botnet detection research in mobile network environments is ***,the existing research focused on AI-based IoT Botnet detection research in wired network *** addition,the existing research related to IoT Botnet detection in ML-based mobile network environments have been conducted up to ***,this paper conducts a study on ML-based IoT Botnet traffic detection in the 5G core *** binary and multiclass classification was performed to compare simple normal/malicious detection and normal/threetype IoT Botnet malware *** both classification methods,the IoT Botnet detection performance using only 5GC’s GTP-U packets decreased by at least 22.99%of accuracy compared to detection in wired network *** addition,by conducting a feature importance experiment,the importance of feature study for IoT Botnet detection considering 5GC network characteristics was *** this paper analyzed IoT botnet traffic passing through the 5GC network using ML and presented detection results,think it will be meaningful as a reference for research to link AI-based security to the 5GC network.

关键词： IoT botnet 5G B5G malware machine learning

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FEA technique of hot plate forming process using cell-typed die with cooling device

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中国有色金属学会会刊：英文版 2012年第S3期22卷 831-837页

作者： Jung-min LEE In-Kyu LEE Kyung-Hun LEE Dae-Soon kim Byung-min kim Dongnam Regional Division Korea Institute of Industrial Technology School of Mechanical Engineering Pusan National University Industrial Technology Division Hyundai Heavy Industries

Hot plate forming using a cell-typed die is a process for forming a large thick plate with a spherical shape for the manufacture of a large spherical LNG ***-typed upper and lower dies made of a framework of steel plates fitted to make a grid pattern are used in this process,and an air-cooling device is separately installed inside the lower die.A finite element analysis (FEA) technique was developed,which included hot forming,air flow,cooling and thermal deformation analysis for the hot plate forming process using the cell-typed ***,the convective and interface heat transfer coefficients were used to reproduce analytically the effects of the cooling device in the hot plate forming analysis.A small-scale model test of the process was conducted to verify the FEA *** analysis results show that the curvature of the final plate agrees well with that of the designed experiment within a maximum relative error of 0.03% at the corner of the plate.

关键词： cell-typed die hot plate forming spherical LNG tank heat transfer coefficient

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Design of 256 bit single-poly MTP memory based on BCD process

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Journal of Central South University 2012年第12期19卷 3460-3467页

作者： kim Kwang-il kim min-sung PARK Young-bae PARK Mu-hun HA Pan-bong kim Young-hee Department of Electronic Engineering Changwon National University9 Sarim-DongChangwon 641-773Korea

We propose a single-poly MTP （multi-time programmable） cell consisting of one capacitor and two transistors based on MagnaChip＇s BCD process. The area of a unit cell is 37.743 75μm^2. The proposed single-poly MTP cell is erased and programmed by the FN tunnelling scheme. We design a 256 bit MTP memory for PMICs （power management ICs） using the proposed single-poly MTP cells. For small-area designs, we propose a selection circuit between V10V and VSV, and a WL （word-line） driver by simplifying its logic circuit. We reduce the total layout area by using pumped internal node voltages from a seven-stage cross-coupled charge pump for V10V （=10 V） and V5V （=5 V） without any additional charge pumps. The layout size of the designed 256 bit MTP memory is 618.250 μm × 437.425μm.

关键词： multi-time programmable memory PMIC cross-coupled charge pump

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Clinicopathological features of familial adenomatous polyposis in Korean patients

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World Journal of Gastroenterology 2016年第17期22卷 4380-4388页

作者： sung min Jung Yong Sik Yoon Seok-Byeong Lim Chang Sik Yu Jin Cheon kim Division of Colon and Rectal Surgery Department of Surgery University of Ulsan College of Medicine Seoul 05505 South Korea Asan Medical Center Seoul 05505 South Korea

AIM: To identify prognostic factors and to correlate APC mutations with clinical features, including extracolic manifestations. METHODS: One hundred thirty-five patients who underwent surgical procedures for familial adenomatous polyposis(FAP) were included. FAP was diagnosed when the number of adenomatous polyps was > 100. Data related to patient, extracoloic manifestations, cancer characteristics, operative procedure, follow up and surveillance were collected. APC mutation testing was performed in the 30 most recent patients. DNA was extracted from peripheral blood and polymerase chain reaction products using 31 primer pairs on APC gene were sequenced. A retrospective study was performed to investigate a causal relationship between prognosis and feature of ***: The mean age of the 51 patients with colorectal cancer(CRC) was older than that of those without CRC(30.5 vs 36.9, P = 0.002). Older individuals were more likely to have colon cancer at the time of FAP diagnosis [odds ratio, 4.75(95%CI: 1.71-13.89) and 5.91(1.76-22.12) for 40-49 years and age > 50 vs age < 30). The number of confirmed deaths was 13 and the median age at death was 40 years(range, 27 to 85 years). Ten of the deaths(76.9%) were from CRC. Another cause of two cases of death were desmoid tumors(15.4%). Development of cancer on remnant rectal or ileal mucosa after surgery was not observed. The APC mutation testing revealed 23 pathogenic mutations and one likely pathogenic mutation, among which were four novel mutations. The correlation between mutational status and clinical manifestations was investigated. Mutations that could prodict poor prognosis were at codon 1309 which located on mutation cluster region, codon 1465 and codon ***: Identification of APC mutations should aid in the diagnosis and counseling of family members in terms of early diagnosis and management of FAP.

关键词： Adenomatous polyposis coli Colorectal neoplasms APC gene Prognosis Survival

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Tracking of horizontal alignment of the long and large diameter uncharged hole in NATM tunnel

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Underground Space 2024年第3期16卷 18-28页

作者： min-Seong kim Sean Seungwon Lee Department of Energy and Resources Engineering Chonnam National UniversityGwangju 61186Republic of Korea Department of Earth Resources and Environmental Engineering Hanyang UniversitySeoul 04763Republic of Korea

The long and large diameter uncharged hole boring(LLB)method is a cut blasting method that minimizes blast-induced vibrations by creating long and large diameter uncharged holes at the excavation face of tunnels prior to tunnel *** in this method typically uses a 50 m long with a 382 mm diameter hammer bit in the horizontal direction at the tunnel ***,the significant weight and uni-directional rotation of the rod head,as well as variables such as geological characteristics,machine conditions,and inexperienced operators result in significant deviation from the target borehole alignment that hinders the vibration-dampening effect of the uncharged ***,since there is no method to verify the alignment of the boreholes until main tunnel construction,borehole misalignment is often not discovered until weeks after construction,which requires tunnel construction to cease until the equipment can be remobilized and an additional borehole be created,causing significant delays and increased costs for the entire tunnel *** this study,the borehole alignment tracking and ground exploration system(BGS)is developed to predict and monitor the quality and alignment of boreholes for cut blasting methods such as the LLB methods immediately after *** BGS was subsequently tested at a subway construction site to evaluate its performance in the *** measurements yielded by the BGS were compared with manually measured boring positions at every 5 m along the *** the BGS showed a maximum deviation of approximately 12%at a local point where the hole surface was relatively rough,the accuracy for the final boring position was approximately 97%,demonstrating excellent precision of the alignment tracking *** BGS demonstrates excellent performance in predicting ground conditions and the boring quality of a cut hole immediately after drilling,and shows promise in various other applications for monitoring borehole alignment.

关键词： Tunnel blasting LLB method Drilling deviation Vertical sagging Horizontal alignment tracking BGS

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Biliary phytobezoar resulting in intestinal obstruction

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World Journal of Gastroenterology 2013年第1期19卷 133-136页

作者： Yura kim Beom Jin Park min Ju kim Deuk Jae sung Dong-Sik kim Young-Dong Yu Jeong Hyeon Lee Department of Radiology College of MedicineKorea UniversityAnam HospitalSeoul 136-705South Korea Division of HBP Surgery and Liver Transplantation Department of SurgeryCollege of MedicineKorea UniversityAnam HospitalSeoul 136-705South Korea Department of Pathology College of MedicineKorea UniversityAnam HospitalSeoul 136-705South Korea

Phytobezoar is the most common type of *** is composed of indigestible vegetable matter and is usually found in the *** phytobezoar is extremely rare and difficult to diagnose *** pathogenesis is not clear,and there have been only a few reports of biliary bezoars associated with sphincteric impairmentat the ampulla of ***,we present a report of biliary bezoar that resulted in jejunal *** were unable to identifythe bezoar in the extrahepatic bile duct until it obstructed the small bowel *** our knowledge,this is the first report of small bowel obstruction resulting frommigration of a biliary bezoar.

关键词： Phytobezoar Biliary Intestinal obstruction Choledochoduodenal Fistula Multidetector-row computed tomography

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Evaluation of the relationship between two different methods for enumeration fecal indicator bacteria: Colony-forming unit and most probable number

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Journal of Environmental Sciences 2010年第6期22卷 846-850页

作者： Kyung Hwa Cho Dukki Han Yongeun Park Seung Won Lee sung min Cha Joo-Hyon Kang Joon Ha kim Department of Environmental Science and Engineering Gwangju Institute of Science and Technology Deparment of Civil and Environmental Engineering Dongguk University-Seoul Sustainable Water Resource Technology Center Gwangju Institute of Science and Technology

Most probable number （MPN） and colony-forming unit （CFU） estimates of fecal indicator bacteria （FIB） concentration are common measures of water quality in aquatic environments. Thus, FIB intensively monitored in Yeongsan Watershed in an attempt to compare two different methods and to develop a statistical model to convert from CFU to MPN estimates or vice versa. As a result, the significant difference was found in the MPN and CFU estimates. The enumerated Escherichia coli concentrations in MPN are greater than those in CFU, except for the measurement in winter. Especially in fall, E. coli concentrations in MPN are one order of magnitude greater than that in CFU. Contrarily, enterococci bacteria in MPN are lower than those in CFU. However, in general, a strongly positive relationship are found between MPN and CFU estimates. Therefore, the statistical models were developed, and showed the reasonable converting FIB concentrations from CFU estimates to MPN estimates. We expect this study will provide preliminary information towards future research on whether different analysis methods may result in different water quality standard violation frequencies for the same water sample.

关键词： most probable number colony-forming unit fecal indicator bacteria Escherichia coli enterococci

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