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Optimization of a High speed spinning Disk spindle system for Minimum RRO,NRRO,and Lightweight by Using G.A.

厦门大学学报(自然科学版) 2002年第S1期41卷 89-90页

作者： Y H choi s T kim K c Yoon J M kim Y J Kang Dept.of Mechanical Design and Manufacturing Changwon National UniversityKyungnam 641-773Korea Dept.of Mechanical Engineering Changwon National UniversityKyungnam 641-773Korea senoir Research Engineer R&D Cente FAGHANWHA Bearing Corp.Kyungnam 641-020Korea Graduate student Dept.of Mechanical Design and ManufacturingChangwon National UniversityKyungnam 6412773Korea

Law level of RRO(Repeatable Run Out),NRRO(Non Repe at able Run Out),and lightweight construction are a major trend in the high-speed HDD(Hard Disk Drive)sytem to reduce track misregestration and to achieve high track density,which lead to succeed in the ***,it is not easy to r educe RRO,NRRO,and the weight of the spinning disk spindle system efficiently because lightweight construction and or bearing stiffness changes often yields a decrease in the static and dynamic stiffness of the system,and consequently hi gh vibrations may be generated as a ***,it is of importance to e valuate in advance the accurate dynamic behavior of the high speed spinning disk spindle system of a HDD *** study introduces an optimum design of the high speed spinning disk spindle system of a HDD for minimum RRO,NRRO,and lightweight construction using a gene tic *** spinning disk,hub,and bearing components of a HDD system ar e modelled as appropriate finite elements respectively and their equations of mo tion are derived to construct the system equations of the whole spinning disk sp indle system of the HDD *** RRO and NRRO responses of the spinning disk,due to exciting forces arised from ball bearing faults and rotating unbalance,are *** the design optimation,the hub thickness,the disk thickness,bearing positio ns(or bearing span)and bearing stiffness were set as design *** uni que objective function is obtained by multiplying an appropriate weighting facto r by multi-objective functions,such as RRO,NRRO,and the total weight of HDD the *** constraints are maximum RRO limit,maximum weight linit,and the critical speed limit of the HDD spindle *** show that the RRO,NRRO,and weight are reduced by 6%,66.7%and 28%r espectively compared with the initial design of the HDD ***,thi s present study can be used for an optimum design of the spinning disk spindle s ystem of a HDD for lightweight construction

关键词： design optimization genetic algorithm multiobjective optimization repeatable run out non repeatable run out

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Platinum quantum dots-decorated MXene-derived titanium dioxide nanowire/Ti_(3)c_(2) heterostructure for use in solar-driven gas-phase carbon dioxide reduction to yield value-added fuels

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Journal of Energy chemistry 2023年第7期82卷 627-637,I0013页

作者： Kamakshaiah charyulu Devarayapalli s.V.Prabhakar Vattikuti Dong Jin kim Youngsu Lim Bolam kim Gyuhyeon kim Dae sung Lee Department of Environmental Engineering Kyungpook National UniversityBuk-guDaegu 41566Republic of Korea Research Institute of Environmental science&Technology Core Research InstituteKyungpook National UniversityBuk-guDaegu 41566Republic of Korea school of Mechanical Engineering Yeungnam UniversityGyeongsan 38541Republic of Korea school of Architecture CivilEnvironmental and Energy EngineeringKyungpook National UniversityBuk-guDaegu 41566Republic of Korea

solar-driven photocatalytic cO_(2) reduction to produce valuable chemicals and fuels offers an attractive strategy in alleviating the energy *** quantum dots(PtQDs)with TiO_(2) nanowire(TiO_(2)NW)/Ti_(3)c_(2) MXene heterostructures(Pt-TiO_(2)NW/Ti_(3)c_(2)) with tight interfacial contacts between the various components were prepared at room temperature via oxidation *** incorporated PtQDs played crucial roles as electron conduction bridges supported by the cocatalyst effect,effectively enhancing the separation efficiencies of photoinduced electron/hole pairs and improving cO_(2) reduction under simulated solar light *** Pt-TiO_(2)NW/Ti_(3)c_(2) heterostructures exhibited remarkable carbon monoxide(cO)and methane(cH_(4)) production at respective rates of 38.14 and 36.15μmol g^(-1)after 10 h of simulated solar light irradiation,an apparent quantum yield of 1.68%,and 79.2%selectivity for *** photocatalytic activities of the Pt-TiO_(2) NW/Ti_(3)c_(2) heterostructures for cO_(2) reduction were significantly enhanced compared to those of TiO_(2)NW/Ti_(3)c_(2) and the single-component photocatalysts,and they exhibited remarkable stabilities even after five *** addition,the densities of states and electronic characteristics of Ti_(3)c_(2) MXene and Pt-TiO_(2)NW/Ti_(3)c_(2) were studied using density functional theory,and a synergistic mechanism of the improvement in cO_(2) photoreduction is proposed.

关键词： MXene cO_(2)reduction Density functional theory Quantum dot Photocatalyst

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Photoluminescence enhancement of red-emitting GdVO_4:Eu and YVO_4:Eu phosphors by adding zinc

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Journal of Rare Earths 2013年第1期31卷 13-17页

作者： K.Park J.kim K.Y.kim J.Y.kim Y.kim s.J.Dhoble Faculty of Nanotechnology and Advanced Materials Engineering Sejong University Department of Advanced Materials Engineering Hoseo University Department of chemistry and Institute of Basic sciences Dankook University Department of Physics R.T.M. Nagpur University

We synthesized the rare-earth activated Ro.94_xEuo.06ZnxVO4 （R： Gd and Y; 0〈_x〈_0.08） phosphors with a spherical mor- phology and a smooth surface by the ultrasonic spray pyrolysis. The annealed Ro.94_xEuo.06ZnxVO4 crystallized in the tetragonal zircon type structure, belonging to the space group of I41/amd. The incorporation of a small amount of Zn to Ro.94Euo.06VO4 improved the emission characteristics. The emission intensities of the Gdo.88EUo.06Zno.06VO4 and Yo.9Euo.06Zno.04VO4 phosphors at 619 nm were 72% and 2 1% stronger than those of the Gdo,94Euo.06VO4 and Yo.94Euo.06VO4 phosphors, respectively. We demonstrated that the addi- tion of Zn to Ro.94Euo.06VO4 was quite effective for improving the photoluminescent properties.

关键词： rare earths photolurninescence vanadate ultrasonic spray pyrolysis

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Impacts of weaning weights and mycotoxin challenges on jejunal mucosa-associated microbiota,intestinal and systemic health,and growth performance of nursery pigs

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Journal of Animal science and Biotechnology 2022年第5期13卷 1440-1457页

作者： D.M.Holanda s.W.kim Department of Animal science North Carolina State UniversityRaleigh 27695USA

Background:This study aimed at investigating the effects of mycotoxin challenge on the growth and physiology of nursery pigs with different weaning ***:At weaning,10 pigs were euthanized to collect jejunal mucosa and 90 pigs were assigned following a randomized complete block design in a 2×2 factorial arrangement of treatments with 3 pigs per *** were:weaning weight(light:body weight,BW9.0 kg);and dietary mycotoxins(supplementation of 0.2 mg/kg aflatoxins,2.0 mg/kg deoxynivalenol).All diets had titanium dioxide as an external marker at 0.5%.Growth performance and fecal score were recorded until pigs achieved 20 kg BW(light pigs average BW=21.1 kg and heavy pigs average BW=20.5 kg).Pigs were sampled for blood,ileal digesta,jejunal tissue and mucosa at 20 kg *** were analyzed using the mixed procedure of *** weaning,light pigs had decreased(Pcreased(Pcrosis factor-α,and increased(Psity indexes of jejunal mucosa-associated *** 20 kg of BW,light pigs had decreased(Pcotoxins decreased(Ps tended to have increased fecal score on d 0(P=0.080),d 10(P=0.069),and increased(Pcal score at 20 *** decreased the apparent ileal digestibility of nitrogen(Ps had increased(Pstinal malondialdehydes and interleukin *** tended to increase(P=0.060)intestinal tumor necrosis factor-α.conclusions:Nursery pigs with light weaning weight were more susceptible to jejunal inflammation and had impaired intestinal health due to weaning stress,whereas mycotoxins diminished the health and growth of nursery pigs regardless of weaning weight.

关键词： Growth Health Mycotoxins Nursery pig Weaning weight

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settling basin design in a constructed wetland using Tss removal efficiency and hydraulic retention time

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Journal of Environmental sciences 2014年第9期26卷 1791-1796页

作者： soyoung Lee Marla c.Maniquiz-Redillas Lee-Hyung kim Water Environment Research Dept. National Institute of Environmental ResearchHwangyeong-ro 42Seo-guIncheon 404-708Korea Dept.of civil & Envi.Eng'g. Kongju National University275 BudaedongSeobukguCheonanChungnamdo 331-717Korea

Using total suspended solid （Tss） removal efficiency and hydraulic retention time （HRT） as design parameters a design guideline of a settling basin in a constructed wetland （cW） was suggested; as well as management of sediment and particle in the settling basin. The cW was desiEned to treat the piggery wastewater effluent from a wastewater treatment plant during dry days and stonnwater runoff from the surrounding paved area during wet days. The first settling basin （FsB） in the cVV was theoretically designed with a total storage volume （TsV） of 453 ms and HRT of 5.5 hr. The amount of sediment and particles settled at the FsB was high due to the sedimentation and interception of plants in the cVV. Dredging of sediments was performed when the retention rate at the FsB decreased to approximately 80%. Findings showed that the mean flow rate was 21.8 m3/hr less than the designed flow rate of 82.8 m3/hr indicating that the FsB was oversize and operated with longer HRT （20.7 hr） compared to the design HRT. An empirical model to estimate the length of the settling basin in the cW was developed as a function of HRT and desired Tss removal efficiency. Using the minimum tolerable Tss removal efficiency of 30%, the length of the FsB was estimated to be 31.2 m with 11.8 hr HRT.

关键词： constructed wetlandHydraulic retention timeParticle size distributionsettling basin designTss removal efficiency

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Optimization of casting conditions for heat and abrasion resistant large grey iron castings

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china Foundry 2007年第2期4卷 124-127页

作者： s. M. Yoo Y. s. cho c. c. Lee J. H. kim c. H. kim J. K. choi center for e-Design Korea Institute of Industrial TechnologyYeonsugu Sondodong 7-47Incheon 406-800Korea Kwanghee casting Mfg. co. Seogu Kyungseodong 381-75Incheon 404-170Korea R&D center Doosan Engine Co. Ltd. Sinchondong 69-3 Changwon 641-370 Korea

Numerical simulation technology was applied for optimizing the casting design and conditions in large cast iron castings for marine engine. By the simulation of mold filling and solidification sequences the problems of the previous casting conditions were analyzed and marked improvements for large cylinder liner parts were derived from these results. Especially the amount and positions of chills were optimized to increase the mechanical properties and to minimize the shrinkage and microporosity in the castings. Ultrasonic testing, penetration testing and mechanical property testing were carried out for the parts with the modified casting conditions. It showed that no defects in the castings were found and the productivity could be distinctly increased. The mechanical properties satisfied also the specification demanded.

关键词： grey cast iron numerical simulation marine engine cylinder liner chill casting design optimization

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Properties of Dispersion casting of Y2O3 Particles in Hypo,Hyper and Eutectic Binary Al-cu Alloys

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Journal of Materials science & Technology 2008年第1期24卷 57-59页

作者： J.J.Park G.H.kim s.M.Hong s.H.Lee M.K.Lee c.K.Rhee Nuclear Nano-Materials Development Lab. Korea Atomic Energy Research Institute （KAERI） 150 Deukjin-dongYuseong-gu Daejeon Korea

In the present work,the dispersion casting of Y-2O-3 particles in aluminum-copper alloy was investigated in terms of microstructural changes with respect to cu contents of 20 （hypo）,33 （eutectic） and 40 （hyper） wt pct by scanning electron microscopy （sEM） and energy dispersive spectroscopy （EDs）.For the fabrication of Al-cu alloy dispersed Y-2O-3 ceramic particles,stir casting method was *** case of Al-20 wt pct cu alloy （hypoeutectic）,sEM images revealed that primary Al was grown up in the *** that,eutectic phase with well dispersed ceramic particles was *** case of eutectic composition,Y-2O-3 particles were uniformly dispersed in the *** the cu is added into Al up to 40 wt pct （hypereutectic）,primary phase was grown up without any Y-2O-3 ceramic particles in the early stage of ***, eutectic phase was formed with well dispersed ceramic *** can be concluded that Y-2O-3 ceramic particles is mostly dispersed in case of eutectic composition in Al-cu alloy.

关键词： Dispersion casting Y2O3 particles stir casting Al-cu alloy

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Identification of the Amplification Mechanism in the First Free-Electron Laser as Net stimulated Free-Electron Two-Quantum stark Emission

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chinese Physics Letters 2009年第5期26卷 86-89页

作者： s. H. kim 6300 Roundrock Trail 4203 Plano Texas 75023 USA

We find that the electron phase with respect to the incident laser radiation must be random in the first freeelectron laser （FEL） and, hence, the incident laser radiation works as a relaxation force to keep a Maxwellian distribution. We formulate the threshold laser intensity for amplification which agrees with the measured value in the order of magnitude in the first FEL. The magnetic wiggler must produce an electric wiggler whose period is the same as that of the magnetic wiggler. We find that net stimulated free-electron two-quantum stark （FETQs） emission driven by this electric wiggler is the mechanism responsible for the measured gain and the measured laser intensity at the plateau in the first FEL.

关键词： gamma-ray bursts gamma-rays relativity

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2D Ti_(3)c_(2)T_(x)MXene-derived self-assembled 3D TiO_(2)nanoflowers for nonvolatile memory and synaptic learning applications

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Journal of Materials science & Technology 2023年第19期150卷 1-10页

作者： Atul c.Khot Tukaram D.Dongale Kiran A.Nirmal Jayan K.Deepthi santosh s.sutar Tae Geun kim school of Electrical Engineering Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841Republic of Korea computational Electronics and Nanoscience Research Laboratory School of Nanoscience and BiotechnologyShivaji UniversityKolhapur 416004India Rajagiri school of Engineering and Technology(Autonomous) Rajagiri ValleyKakkanadKochiKerala 682039India Yashwantrao chavan school of Rural Development Shivaji UniversityKolhapur 416004India

Two-dimensional(2D)semiconducting materials and transition-metal oxides are promising materials for nonvolatile memory and brain-inspired neuromorphic computing ***,it remains chal-lenging to obtain high-quality stacked 2D films with low energy consumptions(or drive currents)be-cause of their high interfacial *** this study,we synthesized 2D Ti_(3)c_(2)T_(x)MXene-derived three-dimensional(3D)TiO_(2)nanoflowers(NFs)as a feasible resistive switching(Rs)material with outstanding electronic properties and synaptic learning *** electrical and optical characteristics of the synthesized material were determined through density functional theory *** measure-ments of the Al/Ti_(3)c_(2)T_(x)-TiO_(2)NF/Pt memory device indicated the occurrence of forming-free switching phenomena with extremely low switching voltages(0.68-0.53 V),stable ON/OFF ratio(2.3×103),and retention greater than 105 *** Holt-Winters exponential smoothing technique was used for mod-eling and predicting the switching voltages of the Rs *** mechanism underlying the reliable Rs was confirmed by observing the dense conductive filaments through conductive atomic force ***,the 2D Ti_(3)c_(2)T_(x)MXene-derived 3D TiO_(2)NF-based Rs device mimicked the po-tentiation/depression and spike-time-dependent plasticity of a biological ***,a convolutional neural network was implemented based on the observed synaptic weights of Al/Ti_(3)c_(2)T_(x)-TiO_(2)NF/Pt for image-edge detection.

关键词： MXene Ti_(3)c_(2)T_(x)-TiO_(2)nanoflowers Resistive switching synaptic learning Density functional theory Time-series analysis

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Wearable sensors and supercapacitors using electroplated-Ni/ZnO antibacterial fabric

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Journal of Materials science & Technology 2022年第5期100卷 254-264页

作者： Taegun kim chanwoo Park Edmund P.samuel Yong-Il kim seongpil An sam s.Yoon school of Mechanical Engineering Korea UniversitySeoul 02841Republic of Korea KU-KIsT Green school Korea UniversitySeoul 136-713Republic of Korea sKKU Advanced Institute of Nanotechnology(sAINT)and Department of Nano Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea

Herein,nickel nanocones and zinc oxide nanosheets were electroplated onto a fabric to produce multifunctional(wearable,stretchable,washable,hydrophobic,and antibacterial)materials with sensing,heating,and supercapacitive *** these functionalities are integrated into a one-layered fabric that can be used as a portable intelligent electronic textile for potential application in healthcare monitoring,smart sportswear,and energy *** nickel enhances the electrical conductivity and thus increases the electron charge transfer for supercapacitor *** integration of ZnO with the Ni-plated fabric provides pseudocapacitance via redox reactions with the *** resistance of the Ni/ZnO fabric changes in response to external stimuli such as temperature and *** voltage is applied,the fabric generates heat through Joule heating,demonstrating its potential application as winter *** superior mechanical durability of the fabric was confirmed through bending and stretching *** hydrophobic surface prevents viruses contained in liquid droplets from infiltrating the *** addition,bacterial growth is inhibited because of the antibacterial properties of the Ni/ZnO fabric and because of Joule *** one-layered fabric integrated with such multiple functionalities is expected to be applicable in the development of next-generation portable and wearable electronic textiles in various industries.

关键词： Multifunctional conductive fabric Fabric supercapacitor Fabric heater Thermal and strain sensors Electroplating

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