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Evaluation of ring surfaces with several coatings for friction,wear and scuffing life

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中国有色金属学会会刊：英文版 2009年第4期19卷 992-996页

作者： dae-hyun CHO Young-Ze lee School of Mechanical Engineering Sungkyunkwan University

Friction and wear of the sliding components in an automobile cause an increase in both fuel consumption and *** engine components involved with sliding contact are all susceptible to scuffing failure at some points during their operating ***,it is important to evaluate the effects of various surface coatings on the tribological characteristics of the piston ring and cylinder block surface of a diesel *** and scuffing tests were conducted using a friction and wear measurement of the piston ring and cylinder block in a low friction diesel *** frictional forces,wear amounts and cycles to scuffing in the boundary lubricated sliding condition were measured using the reciprocating wear *** tester used a piece of the cylinder block as the reciprocating specimen and a segment of the piston ring material as the fixed *** coatings on the ring specimen were used,such as DLC,TiN,Cr-ceramic and TiAlN,in order to improve the tribological characteristics of the *** coefficients of friction were monitored during the tests,and the wear volumes of the piston ring surfaces with various coatings were *** results show that the DLC coating exhibits better tribological properties than the other *** graphite structure of this coating is responsible for the low friction and wear of the DLC *** TiN and DLC coatings show better scuffing resistance than the other *** TiN and Cr-ceramic coated rings show good wear resistance and high friction.

关键词：涂层表面摩擦评价生活划伤磨损

Suppression of pheromone biosynthesis and mating behavior by RNA interference of pheromone gland-specific fatty acyl reductase in Maruca vitrata

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Insect Science 2022年第4期29卷 1135-1144页

作者： Wook hyun Cha dae-Weon lee Department of Biosafety Kyungsung UniversityBusanRepublic of Korea Metabolomics Research Center for Functional Materials Kyungsung UniversityBusanRepublic of Korea

In moths,various enzymes,such as fatty acid synthases,fatty acyl desaturases,and fatty acyl reductases(FARs),are involved in pheromone *** particular,pheromone gland-specific FAR(pgFAR)plays an important role in converting the functional group from carboxylic to alcohol during pheromone biosynthesis.A novel pgFAR of Maruca vitrata,Mvi-pgFAR,was identified through transcriptome sequencing of its pheromone *** investigate the involvement of Mvi-pgFAR in pheromone biosynthesis,Mvi-pgFAR was cloned from the pheromone gland and suppressed by RNA interference(RNAi).Mvi-pgFAR harbored several conserved motifs related to NAD(P)H-binding,N-glycosylation,and adenosine/guanosine triphosphate *** analysis revealed that Mvi-pgFAR with other lepidopteran pgFARs formed an independent ***-pgFAR was specifically expressed only in the pheromone *** real-time polymerase chain reaction showed that the diurnal expression levels of Mvi-pgFAR in the pheromone gland were the highest at 2 h before the *** primarily confirming Mvi-pgFAR suppression by RNAi,(E,E)-10,12-hexadecadienal(E10E12-16:Ald),a major sex pheromone component,was quantified by gas *** Mvi-pgFAR was successfully suppressed,E10E12-16:Ald production was reduced by up to half of that of the control,and the mating rate was subsequently *** results demonstrate that Mvi-pgFAR downregulation can suppress mating behavior by changing the relative sex pheromone component ratio,suggesting that Mvi-pgFAR can be used as a novel control target.

关键词： (EE)-10,12-hexadecadienal gas chromatography Maruca viruta pgFAR RNAi sex pheromone

Low-Programmable-Voltage Nonvolatile Memory Devices Based on Omega-shaped Gate Organic Ferroelectric P(VDF-TrFE) Field Effect Transistors Using p-type Silicon Nanowire Channels

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Nano-Micro Letters 2015年第1期7卷 35-41页

作者： Ngoc Huynh Van Jae-hyun lee Dongmok Whang dae Joon Kang Department of Physics Institute of Basic SciencesSungkyunkwan University School of Advanced Materials Science and Engineering SKKU Advanced Institute of Nanotechnology Sungkyunkwan University

A facile approach was demonstrated for fabricating high-performance nonvolatile memory devices based on ferroelectric-gate field effect transistors using a p-type Si nanowire coated with omega-shaped gate organic ferroelectric poly(vinylidene fluoride-trifluoroethylene)(P(VDF-Tr FE)). We overcame the interfacial layer problem by incorporating P(VDF-Tr FE) as a ferroelectric gate using a low-temperature fabrication process. Our memory devices exhibited excellent memory characteristics with a low programming voltage of ±5 V, a large modulation in channel conductance between ON and OFF states exceeding 105, a long retention time greater than 3 9 104 s, and a high endurance of over 105 programming cycles while maintaining an ION/IOFFratio higher than 102.

关键词： Si nanowires Field effect transistor Ferroelectric memory

Thyroid peroxidase antibody positivity and triiodothyronine levels are associated with pediatric Graves'ophthalmopathy

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World Journal of Pediatrics 2014年第2期10卷 155-159页

作者： Jung hyun lee So hyun Park dae Gyun Koh Byung Kyu Suh Department of Pediatrics the Catholic University of KoreaSt.Vincent's Hospital93-6Ji-dongPaldal-guSuwon-siGyeonggi-doRepublic of Korea Department of Pediatrics the Catholic University of KoreaSeoul St.Mary's Hospital222 Banpo-daeroSeocho-guSeoulRepublic of Korea

Background:Graves'ophthalmopathy(GO)occurs commonly in children with Graves'disease(GD).However,there are limited studies on the clinical manifestations and thyroid autoantibodies in pediatric *** aim of this study was to investigate the prevalence and risk factors of GO in childhood ***:Clinical and biochemical data from children and adolescents with GD were retrospectively *** patients under 19 years of age were included in the present *** compared the clinical and biochemical differences between patients with and without ***:Thirty-nine percent of the patients had GO,and 81%of the GO patients were *** these,two patients showed unilateral ***(T3)levels were higher in GO patients than in those without ***-thyroglobulin antibody and thyroid stimulating hormone receptor antibody titers were not significantly different between the two ***-thyroid peroxidase antibody(TPO Ab)positivity was 68%in the patients with GO and only 47%in the patients without *** multivariate regression analysis,high T3 levels and TPO Ab positivity were related to the presence of ***:In children and adolescents with GD,TPO Ab positivity and high T3 levels could act as predictive factors for the presence of GO.

关键词： Graves'disease Graves'ophthalmopathy pediatrics thyroid peroxidase antibody triiodothyronine

Lubrication properties of silver-palladium alloy prepared by ion plating method for high temperature stud bolt

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 12-16页

作者： Jung-dae KWON Sunghun lee Koo-hyun lee Jong-Joo RHA Kee-Seok NAN Se-Hun KWON Materials Processing Division Korea Institute of Materials Science Changwon Gyeongnam 641-831 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

As a solid lubricant, silver-palladium (Ag-Pd) alloy coating was investigated for the application to high temperature stud bolt. A glue layer nickel (Ni) film was deposited on the surface of the hex bolt sample and then Ag-Pd alloy coating was performed on it using ion plating method. The friction coefficient of Ag-Pd alloy film coated bolt was lower than that of N-5000 oil coated bolt by the result of axial force measurement. The cyclic test of heat treatment was conducted to evaluate the durability of Ag-Pd alloy film coated bolt. In a cycle, sample was assembled into the block using torque wrench, followed by heating and disassembling. It was not successful to disassemble the N-5000 oil coated bolt from the block after only one cycle. However, the Ag-Pd alloy film coated bolt was able to be disassembled softly till 12 cycles.

关键词： solid lubricant silver-palladium alloy ion plating

Fabrication of heteroatom-doped cobalt oxide yolk-shell microsphere using recycled solution from waste materials and their excellent electrochemical properties as an anode material for lithium-ion batteries

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Rare Metals 2024年第10期43卷 4934-4947页

作者： Yeong Beom Kim Chanho Kim Seung-hyun Kim Yun Chan Kang Dongju lee Gi dae Park Department of Advanced Materials Engineering Chungbuk National UniversityChungbuk 28644Korea Department of Materials Science and Engineering Korea UniversitySeoul 136-713Korea Research Institute YKSintering Co.Ltd.Chungbuk 28581Korea

Heteroatom-doped transition metal oxides have attracted great attention as advanced anode materials for lithium-ion batteries due to their high theoretical capacity and superior ***,the limited resource availability has led to a substantial rise in prices for valuable metals such as Ni and Co,posing a significant challenge for their *** address this issue,recycling of these metals from waste materials have gained prominence,and particularly the recovery of Co has been mostly focused on its economic ***,we introduced a novel recycling strategy for fabrication of heteroatomdoped CoO_(x)(comprising mainly Co_(3)O_(4)with a minor CoO phase)anode with a yolk–shell structure for lithium-ion batteries,by separating Co from cemented tungsten carbide *** employing a simple leaching process and subsequent spray pyrolysis,the yolk–shell structured microsphere comprising CoO_(x)was successfully ***,the presence of other waste metals in the leachate facilitated multi-heteroatom doping during ***,the introduction of various dopants into CoO_(x)induced oxygen vacancy formation,thereby enhancing the electrochemical properties of the CoO_(x)*** a result,compared with the phase-pure(undoped)CoO_(x)yolk–shell,the heteroatom-doped CoO_(x)yolk–shell exhibited robust cycling stability(602 mAh·g^(-1)for 200 cycles at 1 A·g^(-1))and excellent rate capability(210 mAh·g^(-1)at 10 A·g^(-1)).

关键词： Recycling Heteroatom doping Cobalt oxide Anode Lithium-ion batteries

Phantom Maps from a Strong Homology Viewpoint

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Acta Mathematica Sinica,English Series 2006年第3期22卷 711-718页

作者： dae Woong lee Department of Mathematics Chonbuk National University

Let X and Y be connected nilpotent CW-complexes of finite type. In this paper we deal with another complete analysis of a set of phantom maps in terms of strong homology by using the derived functors. We also prove that the set of homotopy classes of maps is independent of the choice of both rational homotopy equivalent classes and completion genera.

关键词： Phantom map Derived limit Strong homology Rational equivalence Profinite completion

On the Same n-Types for the Wedges of the Eilenberg-Maclane Spaces

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Chinese Annals of Mathematics,Series B 2016年第6期37卷 951-962页

作者： dae-Woong lee Department of Mathematics Institute of Pure and Applied Mathematics Chonbuk National University

Given a connected CW-space X, SNT（X） denotes the set of all homotopy types [X＇] such that the Postnikov approximations X（n） and X＇^（n） are homotopy equivalent for all n. The main purpose of this paper is to show that the set of all the same homotopy n- types of the suspension of the wedges of the Eilenberg-MacLane spaces is the one element set consisting of a single homotopy type of itself, i.e., SNT（Σ（K（Z, 2a1） ∨ K（Z, 2a2）∨… ∨ K（Z,2ak））） = ＊ for a1 〈 a2 〈 … 〈 ak, as a far more general conjecture than the original one of the same n-type posed by McGibbon and Moller （in [McGibbon, C. A. and Moller, J. M., On infinite dimensional spaces that are rationally equivalent to a bouquet of spheres, Proceedings of the 1990 Barcelona Conference on Algebraic Topology, Lecture Notes in Math., 1509, 1992, 285-293].）

关键词： Same n-type Aut Basic Whitehead product Samelson product Bott-Samelson theorem Tensor algebra Cartan-Serre theorem Hopf-Thom theorem

Clinical impact of atypical endoscopic features in rectal neuroendocrine tumors

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World Journal of Gastroenterology 2015年第47期21卷 13302-13308页

作者： Jong Hee hyun Seong dae lee Eui Gon Youk Jae Bum lee Enu-Jung lee Hee Jin Chang dae Kyung Sohn Center for Colorectal Cancer National Cancer Center Department of Surgery Daehang Hospital

AIM: To validate the association between atypical endoscopic features and lymph node metastasis(LNM).METHODS: A total of 247 patients with rectal neuroendocrine tumors(NETs) were analyzed. Endoscopic images were reviewed independently by two endoscopists, each of whom classified tumors by sized and endoscopic features, such as shape, color, and surface change(kappa coefficient 0.76 for inter-observer agreement). All of patients underwent computed tomography scans of abdomen and pelvis for evaluation of LNM. Univariate and multivariate analyses were performed to identify the factors associated with LNM. Additionally, the association between endoscopic atypical features and immunohistochemical staining of tumors was ***: Of 247 patients, 156(63.2%) were male and 15(6.1%) were showed positive for LNM. On univariate analysis, tumor size(P < 0.001), shape(P < 0.001), color(P < 0.001) and surface changes(P < 0.001) were significantly associated with LNM. On multivariate analysis, tumor size(OR = 11.53, 95%CI: 2.51-52.93, P = 0.002) and atypical surface(OR = 27.44, 95%CI: 5.96-126.34, P < 0.001) changes were independent risk factors for LNM. The likelihood of atypical endoscopic features increased as tumor size increased. Atypical endoscopic features were associated with LNM in rectal NETs < 10 mm(P = 0.005) and 10-19 mm(P = 0.041) in diameter. Immunohistochemical staining showed that the rate of atypical endoscopic features was higher in non L-cell ***: Atypical endoscopic features as well as tumor size are predictive factors of LNM in patients with rectal NETs.

关键词： Rectal neuroendocrine tumor Colonoscopy Lymph node metastasis