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Visual Informatics 2020年第2期4卷 122-131页

作者： Yiran Li Takanori Fujiwara Yong k.choi katherine k.kim kwan-Liu Ma Department of Computer Science University of CaliforniaDavisUnited States Betty Irene Moore School of Nursing University of CaliforniaDavisUnited States School of Medicine University of CaliforniaDavisUnited States

There is a growing trend of applying machine learning methods to medical datasets in order to predict patients’future *** some of these methods achieve high performance,challenges still exist in comparing and evaluating different models through their interpretable *** analytics can help clinicians improve evidence-based medical decision *** this work,we develop a visual analytics system that compares multiple models’prediction criteria and evaluates their *** our system,users can generate knowledge on different models’inner criteria and how confidently we can rely on each model’s prediction for a certain *** a case study of a publicly available clinical dataset,we demonstrate the effectiveness of our visual analytics system to assist clinicians and researchers in comparing and quantitatively evaluating different machine learning methods.

关键词： Clinical data XAI Tree-based machine learning models Model consistency Measures of dependence Visual analytics

exploration of chromene-based BioAIegens

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National Science Review 2024年第3期11卷 47-48页

作者： Fritz e.kühn Department of Chemistry&Catalysis Research Center School of Natural Sciences Technical University of Munich

Photoemission efficiency is usually higher in solution than in solid *** compounds however, display a reverse behavior. Such a behavior is called aggregation-induced emission(AIe).

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Improvement of Deep Groove Ball Bearing’s Performance Using a Bionic Textured Inner Race

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Journal of Bionic engineering 2021年第4期18卷 974-990页

作者： k.e.Ch.Vidyasagar R.k.Pandey Dinesh kalyanasundaram Center for Biomedical engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical engineering College of EngineeringOsmania UniversityHyderabad500007India Department of Mechanical engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical engineering All India Institute of Medical SciencesNew Delhi110029India

Micro-textured surfaces have improved the tribological performance of contact surfaces under lubricated conditions;however,not practiced due to manufacturing *** addition to simpler micro-pits or straight-trench type textures,sophisticated bioinspired textures on commercial radial ball bearings have been scarcely *** this work,Dendroaspis polylepis(Mamba snake)skin-type textures were fabricated on the inner race of FAG radial ball bearings using a nanosecond fiber laser *** the snake textures were primarily meant to enhance friction,the dimensions of the texture have been carefully chosen to improve the tribological performance under lubricated *** textured bearings were assembled and experimented at various rotational speeds and lightly loaded conditions to measure vibrational amplitude,frictional torque,and temperature *** to untextured(conventional)bearing,the snake-skin type textured bearings resulted in improved tribo-dynamic performance.

关键词： bionic texture radial ball bearing frictional torque vibration temperature

An exploration of frictional and vibrational behaviors of textured deep groove ball bearing in the vicinity of requisite minimum load

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Friction 2021年第6期9卷 1749-1765页

作者： k.e.Ch.VIDYASAGAR R.k.PANDeY Dinesh kALYANASUNDARAM Center for Biomedical engineering Indian Institute of Technology DelhiNew Delhi 110016India Department of Biomedical engineering College of EngineeringOsmania UniversityTelangana 500007India Department of Mechanical engineering Indian Institute of Technology DelhiNew Delhi 110016India Department of Biomedical engineering Indian Institute of Technology DelhiNew Delhi 110016India

In case of lightly loaded radial ball bearings,failure mechanisms other than fatigue such as smearing of raceways due to increased frictional torque and vibrations often ***,attempts have been made herein for reducing the frictional torque and minimizing the vibrations of a radial deep groove ball bearing employing surface textures at the inner *** pulsed laser was used to create texture(involving micro-dimples having different dimple area density)on the inner race of test *** an in-house developed test rig,frictional torque and vibrational parameters were measured at different speeds and light loads(*** vicinity of 0.01C,where C is dynamic load capacity of radial ball bearing).Significant reduction in frictional torque and overall vibrations were found in the presence of micro-dimples on inner race at light loads irrespective of operating *** without satisfying the minimum load needed criteria for the satisfactory operation,substantial reduction in smearing marks was found on the races of textured ball bearings in comparison to conventional cases.

关键词： ball bearing textured inner race grease lubricated frictional torque vibration

Invariant operator theory for the single-photon energy in time-varying media

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Chinese Physics B 2010年第1期19卷 56-60页

作者： choi Jeong-Ryeol School of electrical engineering and Computer Science Kyungpook National University

After the birth of quantum mechanics, the notion in physics that the frequency of light is the only factor that determines the energy of a single photon has played a fundamental role. However, under the assumption that the theory of Lewis-Riesenfeld invariants is applicable in quantum optics, it is shown in the present work that this widely accepted notion is valid only for light described by a time-independent Hamiltonian, i.e., for light in media satisfying the conditions, ε（t） = ε（0）, u（t） = u（0）, and σ（t） = 0 simultaneously. The use of the Lewis Riesenfeld invariant operator method in quantum optics leads to a marvelous result： the energy of a single photon propagating through time-varying linear media exhibits nontrivial time dependence without a change of frequency.

关键词： single-photon energy invariant operator theory time-varying media

Cartesian Grid Method with Cut Cell in the Mold Filling Simulation

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Journal of Materials Science & Technology 2008年第3期24卷 379-382页

作者： Youngsim choi Junho Hong Hoyoung Hwang Jeongkil choi Center-for e-Design KITECH7-47-Songdo-DongYeonsu-Ku

In this paper, a Cartesian grid method with cut cell has been developed to simulate mold filling of casting process. Cut cells at the cast-mold interface are generated on the Cartesian grid. With the boundary cut cells, a special treatment is necessary. That is Cartesian grid method with cut cell. A simple shape was tested and the cut cell method was compared with the traditional one on Cartesian grids. And, a developed method was applied to the real casting product simulation. Cartesian grid system causes momentum loss and unsound fluid flow patterns because of inaccurate generation of meshes. These problems have been improved by using cut cell method.

关键词： Cartesian grids Cut cell Momentum loss

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皮革的可塑性 POLeNe首尔专卖店

室内设计与装修 2025年第1期 90-95页

作者：无 Minwoo(Ian)Yang Sunho Shin Hyevin Park Yongjoon choi(摄影) 秋落(编译) WGNB 不详

继巴黎、纽约和东京之后,专注皮革设计的小众品牌Pol$ne于日前在韩国首尔开设首家品牌旗舰店,也是全球第4间专卖店。这个深受时尚迷和年轻一代欢迎的法国小众品牌,将店址选在逛街胜地之一的江南新沙洞,打造了两层的品牌旗舰店。除了延... 详细信息

继巴黎、纽约和东京之后,专注皮革设计的小众品牌Pol$ne于日前在韩国首尔开设首家品牌旗舰店,也是全球第4间专卖店。这个深受时尚迷和年轻一代欢迎的法国小众品牌,将店址选在逛街胜地之一的江南新沙洞,打造了两层的品牌旗舰店。除了延续品牌形象,引进品牌经典包款和人气新作,受到韩国打卡文化的影响,Pol$ne为首尔旗舰店精心规划出拍照空间,凡是走进店内的人,都会忍不住想要拿起手机留下回忆。

关键词：小众品牌旗舰店皮革品牌形象专卖店 Pol

DSC Investigation of Phase Transitions in System LaH_2-LaH_3

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Journal of Rare earths 2002年第2期20卷 98-103页

作者：王龙妹 Conder k kaldis e Central Iron & Steel Research Institute Beijing 100081 China Laboratory of Solid State Physics-eTH CH-8093 Zurich Switzerland

Differential scanning calorimetry (DSC) measurements of 37 polycrystalline LaH x (2 02 45 much more complicated DSC signals (double, triple etc. peaks) were observed which some of them were up to 4 phase transfor... 详细信息

Differential scanning calorimetry (DSC) measurements of 37 polycrystalline LaH x (2 0ere performed in this work. Samples were synthesized by a direct reaction of a metal with hydrogen at temperatures higher than 250 ℃ (depending on the final composition). DSC measurements were performed in the temperature range of 110～400 k. For the samples in the range of 2 13e DSC peaks were detected. In the composition range x >2 45 much more complicated DSC signals (double, triple etc. peaks) were observed which some of them were up to 4 phase transformations. Based on these measurements and carried out on high purity samples and supported by high accuracy hydrogen content determination, a new T-x phase diagram for 110k and 2ed. This new phase diagram shows an up to now unknown complexity phase relationships with the existence of at least 11 of phases at T k.

关键词： rare earths lanthanum LaH 2 LaH 3 Differential scanning calorimetry phase diagram

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in the blocks＇ glass transition temperatures

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Frontiers of Chemical Science and engineering 2017年第3期11卷 440-447页

作者： Yang Zhou Phillip choi Department of Chemical and Materials engineering University of Alberta Edmonton Edmonton AB T6G 1H9 Canada

Isothermal-isobaric molecular dynamics simu- lation was used to study the diffusion mechanism of water in polyurethane-block-poly（N-isopropyl acrylamide）（PU- block-PNIPAm） with a hydrophobic PU/hydrophilic PNIPAm mass ratio of 1.4 to 1 at 298 k and 450 k. Here, the experimental glass transition temperature （Tg） of PU is 243 k while that of PNIPAm is 383 k. Different amounts of water up to 15 wt-% were added to PU-block- PNIPAm. We were able to reproduce the specific volumes and glass transition temperatures （250 k and 390 k） of PU- block-PNIPAm. The computed self-diffusion coefficient of water increased exponentially with increasing water concentration at both temperatures （i.e., following the free volume model of Fujita）. It suggested that water diffusion in PU-block-PNIPAm depends only on its fractional free volume despite the free volume inhomo- geneity. It is noted that at 298 k, PU is rubbery while PNIPAm is glassy. Regardless of temperature, radial distribution functions showed that water formed clusters with sizes in the range of 0.2-0.4 nm in PU-block- PNIPAm. At low water concentrations, more clusters were found in the PU domain but at high water concentrations, more in the PNIPAm domain. It is believed that water molecules diffuse as clusters rather than as individual molecules.

关键词： molecular dynamics simulation amphiphilic block copolymer free volume water diffusivity fujita model

Research trend of cascade heat pumps

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Science China(Technological Sciences) 2017年第11期60卷 1597-1615页

作者： BOAHeN Samuel choi JongMin Graduate School of Mechanical engineering Hanbat National UniversityDaejeon 34158Korea Department of Mechanical engineering Hanbat National UniversityDaejeon 34158Korea

Most commercial and industrial facilities require very low temperatures for refrigeration and high temperatures for space heating and hot water purposes. Single stage heat pumps have not been able to meet these temperature demands and have been characterized by low capacities and coefficient of performance(COP). Cascade heat pump has been developed to overcome the weaknesses of single stage heat pumps. This study reviews recent works done by researchers on cascade heat pumps for refrigeration, heating and hot water generation. Selection of suitable refrigerants to meet the pressure and temperature demands of each stage of the cascade heat pump has been discussed. Optimization of design parameters such as intermediate temperature(low stage condensing and high stage evaporating temperatures), and temperature difference in the cascade heat exchanger for optimum performance of the cascade heat pump has been reviewed. It was found that optimising each design parameter of the cascade heat pump is necessary for maximum system performance and this may improve the exergetic efficiency, especially of cascade refrigeration systems, by about 30.88%. Cascade heat pumps have wider range of application especially for artificial snow production, in the supermarkets,for natural gas liquefaction, in drying clothes and food and as heat recovery system. The performance of cascade heat pumps can be improved by 19% when coupled with other renewable energy sources for various real time applications. Also, there is the need for much research on refrigerant charge amount of cascade heat pumps, refrigerant-refrigerant heat exchangers to be used as cascade heat exchanger, cascade heat pumps for simultaneous cooling, heating and hot water generation and on the use of variable speed compressors and their control strategies in matching system capacity especially at part load conditions.

关键词： cascade heat pump low stage high stage optimization system performance refrigerant