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Some Properties of Degenerate r-Dowling Polynomials and Numbers of the Second Kind

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Computer Modeling in Engineering & Sciences 2022年第12期133卷 825-842页

作者： Hye kyung kim Dae Sik Lee Department of Mathematics Education Daegu Catholic UniversityGyeongsan38430Korea School of Electronic and Electric Engineering Daegu UniversityGyeongsan38453Korea

The generating functions of special numbers and polynomials have various applications in many fields as well as mathematics and *** recent years,some mathematicians have studied degenerate version of them and obtained many interesting *** this in mind,in this paper,we introduce the degenerate r-Dowling polynomials and numbers associated with the degenerate r-Whitney numbers of the second *** derive many interesting properties and identities for them including generating functions,Dobinski-like formula,integral representations,recurrence relations,differential equation and various explicit *** addition,we explore some expressions for them that can be derived from repeated applications of certain operators to the exponential functions,the derivatives of them and some identities involving them.

关键词： Dowling lattice Whitney numbers and polynomials r-Whitney numbers and polynomials of the second kind r-Bell polynomials r-Stirling numbers dowling numbers and polynomials

An evaluation of the influence of impurity concentration and composition in concrete on activation and radiation dose in the reactor facility

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辐射防护 2020年第6期40卷 486-490页

作者： Jae hyun kim Myeong Hyeon WOO Chang Ho SHIN Jong kyung kim Department of Nuclear Engineering Hanyang University222Wangsimni-roSeongdongSeoulKorea

The content analysis of radioactive waste and radiation dose evaluation is considered as one of the important factors in the reactor facility *** kind of buildings consists of the concrete for the most part and uses it as the structure and shield of the ***,the concrete has impurities such as cobalt,europium,nickel,and cesium with specific content depending on the production method or manufacturing *** radioactive nuclides generated from the fundamental components of concrete are considered that it is less contributed to the radiation dose because they are beta decay nuclides in ***,impurities of irradiated concrete in the reactor facilities,are considered occasionally an important evaluation factor for induced *** this study,the influence on the activation of impurities in concrete was evaluated from the radiation dose and induced activity *** calculation was evaluated at the bio-shield which is one of the areas with the highest neutron irradiation among the concrete structure in the reactor *** results show that radioactive nuclides with gamma decay were produced in these ***,the radiation dose of concrete with impurities was higher than concrete without *** increased radiation dose was quantified through the content of impurities.

关键词： radiation dose concrete impurity activation analysis

Oxygen vacancy engineering for tuning the catalytic activity of LaCoO_(3) perovskite

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Journal of Rare Earths 2024年第3期42卷 506-514,I0003页

作者： Jeong hyun Cho Minjae kim Inchan Yang kyung Tae Park Chang Houn Rhee Hai Woong Park Ji Chul Jung Department of Chemical Engineering Myongji UniversityYongin 17058Republic of Korea Institute of Advanced Composite Materials Korea Institute of Science and TechnologyWanju-gunJeollabuk-do 55324Republic of Korea Iron&Steel Process Engineering Research Group POSCOPohang 37859Republic of Korea Hydrogen Research Center Research Institute of Industrial Science&Technology(RIST)Pohang 37673Republic of Korea

Herein, we attempted to engineer oxygen vacancies on the surface of LaCoO_(3) perovskite through simple post-treatments(acid or reductive thermal treatments). Acid treatment induces oxygen vacancies through the selective etching of the La cations, whereas thermal treatment in a reducing atmosphere generates oxygen vacancies by directly removing lattice oxygen. The characterization results confirm that the number of surface oxygen vacancies, which are crucial in various catalytic oxidation reactions,considerably increases in the LaCoO_(3) catalysts treated with acid or reducing gas. Acid treatment enriches the oxygen vacancies while maintaining the structure of the LaCoO_(3) catalysts, which can not be achieved through reductive thermal treatment. Therefore, the acid treatment is considered a promising technique for oxygen vacancy engineering of perovskite catalysts for tuning their catalytic activities. Furthermore,the catalytic activities of the posttreated LaCoO_(3) catalysts for CO oxidation were evaluated and are noted to be considerably better than those of the pristine LaCoO_(3) catalyst due to their abundant oxygen vacancies. Consequently, we conclude that the oxygen vacancies of perovskite catalysts can be effectively engineered via two simple methods and play a significant role in CO oxidation.

关键词： LaCoO_(3)perovskite Acid treatment Reductive thermal treatment Oxygen vacancy CO oxidation Rare earths

Canonical Foliations of Certain Classes of Almost Contact Metric Structures

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Acta Mathematica Sinica,English Series 2005年第4期21卷 841-846页

作者： Tae Wan kim Hong kyung PAK Department of Mathematics Education Silla UniversityPusan617-736.Korea Department of Computer and Information Security Daegu Haany University

The purpose of this paper is to study the canonical foliations of an almost cosymplectic or almost Kenmotsu manifold M in a unified way. We prove that the canonical foliation F defined by the contact distribution is Riemannian and tangentially almost Kahler of codimension 1 and that F is tangentially Kahler if the manifold M is normal. Furthermore, we show that a semi-invariant submanifold N of such a manifold M admits a canonical foliation FN which is defined by the antiinvariant distribution and a canonical cohomology class c（N） generated by a transversal volume form for FN. In addition, we investigate the conditions when the even-dimensional cohomology classes of N are non-trivial. Finally, we compute the Godbillon Vey class for FN.

关键词： Almost α-cosymplectic manifold Almost cosymplectic manifold Almost Kenmotsu manifold Semi-invariant submanifold

Influence of tool deflection on micro channel pattern of 6:4 brass with rectangular tool

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中国有色金属学会会刊：英文版 2009年第B9期19卷 164-170页

作者： Tae-Jin JE Kang-Won LEE Sang-Cheon PARK Jae-Gu kim Doo-Sun CHOI Kyoung-Taik PARK kyung-hyun WHANG Nano Mechanical Systems Research Division Korea Institute of Machinery & Materials (KIMM)

Machining experiment of micro channel structure with 6:4 brass was carried out by shaping process using a single crystal diamond tool. FEM simulation using solid cantilever beam model was analyzed. In result of experiment, tool deflection is observed as machining characteristics through result of experiments such as surface roughness, cutting force and burr formations. And the influence of tool deflection is experimentally proved.

关键词：金刚石工具挠度通道模式黄铜矩形实验证明加工特性有限元模拟

Effects of Polymeric Stabilizers on the Synthesis of Gold Nanoparticles

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Journal of Materials Science & Technology 2014年第2期30卷 107-111页

作者： Eun Jung kim Jeong hyun Yeum Jin hyun Choi Department of Advanced Organic Materials Science and Engineering Kyungpook National University Department of Bio-fibers and materials Science Kyungpook National University

Gold nanoparticles （AuNPs） stabilized with sodium alginate （SA）, glycol chitosan （GC）, polyvinyl alcohol （PVA）, and polyethyleneimine （PEI） were synthesized in aqueous solutions at room temperature. Different sizes and size distributions of AuNPs were obtained according to the polymeric stabilizers. The mean particle diameters of AuNPs synthesized with GC and PVA as stabilizers were about 5.1 and 5.3 nm, respectively, while those of AuNPs stabilized with SA and PEI were 8.4 and 10.8 nm, respectively. When SA was used, relatively large particles aggregated to form large clusters. In the case of GC, a number of small particles built up large clusters. When PVA was used, the size and the number of nanoperticles were estimated small with a low weight content of Au. For this reason, the PVA-stabilized AuNPs formed clusters with a small hydrodynamic size. The AuNPs synthesized in the aqueous solution of PEI without a reducing agent, sodium borohydride, were uniform in size and formed the smallest nanoclusters （67.4 nm）. In this case, the highest Au content was obtained. Sufficiently grown nanoparticles with a high Au content and a limited hydrodynamic size are considered to be suitable for a variety of applications.

关键词： Gold nanoparticles Sodium alginate Glycol chitosan Polyvinyl alcohol Polyethyleneimine

Effect of Isothermal Annealing on Nano Ti-Carbides Precipitation

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Journal of Iron and Steel Research International 2011年第S1期18卷 287-289页

作者： Cheol-ho Park Woo-jin kim Nam-hyun Kang hyung-hyup Do kyung-Mox Cho Department of Materials Science and Engineering Pusan National UniversityBusan 609-735Korea Technical Research Laboratories Hyundai steelsDangjinChungnam 343-711Korea

Transmission electron microscopy was used to investigate the effect of isothermal holding temperature and time on the nano Ti-precipitates.A holding temperature was varied systematically from 400℃ to 1200℃.The isothermal holding was continued for 30s,300s and 900s,*** carbides of (Ti,Nb)C were precipitated significantly at 900℃.The size of carbides was approximately 10nm at 30s holding and increased to 20～30nm at 900s *** holding at 1000℃ showed the increased amount of carbides larger than *** 800℃,nano (Ti,Nb)C was not observed at 30s and it was examined at *** size of nano (Ti,Nb)C was smaller than that of 900℃.As the isothermal temperature decreased to 700 ℃,the nano (Ti,Nb)C was only seen at 900s holding and the size of carbides was smaller than *** (Ti,Nb)C was disappeared at isothermal holding below 600℃.The kinetics of nano (Ti,Nb)C precipitation were studied as a function of isothermal holding temperature and time,respectively,using the precipitate growth equations.

关键词： Ti carbide hot rolled steel hole expansion ratio isothermal holding nano precipitates

Acceleration of aging behavior and improvement of mechanical properties of extruded AZ80 alloy through(10–12) twinning

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Journal of Magnesium and Alloys 2023年第2期11卷 671-683页

作者： hyun Ji kim Ye Jin kim Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

The effects of pre-existing {10–12} extension twins on the precipitation behavior of an extruded AZ80 material during aging and on its mechanical properties after peak aging are investigated. The material containing {10–12} twins-which are formed by compression before aging(twinned material)-has a finer grain size and higher dislocation density than the extruded material. Although the peak hardnesses of the twinned and extruded materials are almost the same, the time to reach the peak hardness is considerably shorter in the former material than in the latter(4 h and 24 h, respectively). In the twinned material, the high dislocation density of the {10–12} twins promotes continuous precipitation, which results in the formation of numerous fine Mg17Al12precipitates within the twins in the early stage of *** formation of these continuous precipitates reduces the driving force for discontinuous precipitation, which consequently suppresses the formation and growth of coarse Mg17Al12precipitates at the grain boundaries. Despite its shorter peak-aging time, the 4 h-peak-aged twinned material shows higher tensile strength and elongation than the 24 h-peak-aged extruded material. These higher mechanical properties of the former material are attributed primarily to the presence of more abundant fine continuous precipitates, which are effective in strengthening the material, and less abundant coarse discontinuous precipitates, which can act as crack initiation sites. These results demonstrate that the introduction of {10–12} twins into wrought Mg–Al-based alloys can accelerate the Mg17Al12precipitation kinetics considerably and improve the strength and ductility of the peak-aged alloys simultaneously.

关键词： AZ80 alloy Twin Aging Precipitation Tensile properties

Anti-obesity Effects of Ginsenosides in High-Fat Diet-Fed Rats

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Chinese Journal of Integrative Medicine 2019年第12期25卷 895-901页

作者： hyun-Jung Park Ji hyun kim Insop Shim Department of Physiology College of MedicineKyung Hee UniversitySeoul(130-701)Republic of Korea Department of Food Science&Biotechnology College of Science and EngineeringSuwon-si(16227)Republic of Korea

Objective: To examine the anti-obesity effects of ginsenosides in Korea Red Ginseng(KRG, Panax ginseng) in rats fed with a high-fat diet(HFD). Methods: Twenty-five 4-week-old obesity rats after receiving an HFD for 5 weeks;subsequently, they were additionally treated with ginsenosides Rb1, Rd, Rg1, or Re(10 mg/kg, intraperitoneal injection) for a further 3 weeks(n=5 in each group). The control rats were fed a normal diet. The food consumption, body weight, locomotor activity, serum lipids, adipose tissues, nitric oxide(NO) expression, leptin, neuropeptide Y(NPY), cholecystokinin(CCK) in the brains were measured. Results: In the HFD-fed rats, body weight, body fat mass, serum levels of leptin and NO were significantly higher than in the control rats(P<0.05 or P<0.01). However, the treatment of Rd, Re, and Rb1 markedly decreased body fat mass and body weight(P<0.05). The serum level of leptin and NO in ginsenoside-treated rats were markedly lower than the control group(P<0.01). The expression of NPY and CCK in the hypothalamic nuclei showed insignificant difference among groups. However, the expression of NPY immunoreactive neurons in the hypothalamus was significantly reduced in the Rb1-treated group(P<0.05). Conclusion: PD-type ginsenoside Rb1 from the crude saponins of KRG may be a useful compound for the treatment of obesity and related disorders through the modulation of peripheral and central appetite-regulating signals.

关键词： Panax ginseng ginsenosides hypothalamus obesity