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Journal of Central South University 2011年第3期18卷 704-710页

作者： KIM jin-seob hwang Jong-dae JUNG Yoon-gyo School of Mechatronics Changwon National University

The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-feed *** order to develop such a machine,3D-modeling and machine simulations were performed and a twin wheel creep-feed grinding machine was ***,the axisymmetric precision of the machined workpieces through practical machining was evaluated and the quality of the continuous dressing effect of the developed machine was *** addition,experimental considerations for a proper dresser-to-wheel speed ratio and proper feed rate of the dresser were carried *** a result,a twin wheel creep-feed grinding machine with continuous dressing is developed through machine simulation,manufacturing and performance *** condition for the dresser feed rate is 0.3μm/*** cases of large dressor-to-wheel speed ratio,grinding efficiency can be enhanced,but the surface roughness shows a conflicting *** twin wheel creep-feed grinding machine has satisfactory appraisal with regard to surface roughness,flatness,and *** surface roughness below 0.1μm can be obtained for the blade of ***,in order to perform precise machining,it is necessary to improve the structure of the twin wheel creep-feed grinding machine.

关键词：进给速度加工工件旋翼飞机磨削机蠕动双轮表面粗糙度计算机仿真

Lightweight design of 45000r/min spindle using full factorial design and extreme vertices design methods

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Journal of Central South University 2011年第1期18卷 153-158页

作者： PARK Seong-jin LEE Choon-man hwang Young-kug Department of Mechanical Design and Manufacturing Engineering Changwon National University

Factors for determining the spindle size are the shaft diameter,positions of bearing and motor,and entire length of the ***,it is important to find the assembling of the optimal design variables,which satisfy the stiffness and rotational speed required to the spindle.A general full factorial design method was used to verify some factors that affect the natural frequency of a *** is verified that the shorter shaft length and bearing span length represent the higher natural frequency,and there are some effects according to the change in the levels of *** detailed spindle dimension is determined by applying an EVD method,which can define the optimal bearing position through considering the limiting *** on the estimated regression model,the optimal spindle size and bearing distance that can improve the primary natural frequency are obtained,and the influence of design factors on the natural frequency is also analyzed.

关键词：主轴轴承因子设计设计方法轻量级自然频率顶点轴承位置设计变量

Polygonal multi-polymorphed Li4Ti5Oi2@rutile TiO2 as anodes in lithium-ion batteries

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Nano Research 2019年第4期12卷 897-904页

作者： Chang Hyun hwang Hee-eun Kim Inho Nam jin Ho Bang Department ofBionano Technology Hanyang University 55 Hanyangdaehak-ro Sangnok-gu Ansan Gyeonggi-do 15588 Republic of Korea School of Chemical Engineering & Materials Science Chung-Ang University 84 Heukseok-ro Dongjak-gu Seoul 06974 Republic of Korea Department of Chemical and Molecular Engineering Hanyang University 55 Hanyangdaehak-ro Sangnok-gu Ansan Gyeonggi-do 15588 Republic of Korea

Li4Ti50i2 (LTO) has attracted considerable attention in lithium-ion battery (LIB) applications because of its favorable characteristics as an anode material. Despite its promise, the widespread use of LTO is still limited primarily due to its intrinsically poor electric and ionic con ductivities and high surface reactivity. To address these issues, we desig ned polyg onal nano architectures composed of various Li-Ti oxide crystal polymorphs by a facile synthesis route. Depending on the pH condition, this synthesis approach yields multi-polymorphed Li-Ti oxides where the interior is dominantly composed of a Li-rich phase and the exterior is a Li-deficient (or Li-free) phase. As one of these variations, a polygonal LTO-rutile TiO2 structure is formed. The rutile TiO2 on the surface of this LTO composite significantly improves the kinetics of Li^+ insertion/extraction because the channel along the o-axis in TQ2 provides a Li^+ highway due to the significantly low energy barrier for Li^+ diffusion. Moreover, the presenee of rutile TiO2, which is less reactive with a carbonate-based electrolyte, ensures Iong-term stability by suppress)ng the undesirable interfacial reaction on LTO.

关键词： micro-polygon structure Li-Ti oxide multi-polymorphs Li4Ti5Oi2@ rutile TiO2 anode lithium-ion batteries

Translation rate underpins specific targeting of N-terminal transmembrane proteins to mitochondria

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Journal of Integrative Plant Biology 2023年第6期65卷 1505-1520页

作者： Junho Lee Byeongho Moon Dong Wook Lee Inhwan hwang Department of Life Science Pohang University of Science and TechnologyPohang 790-784South Korea Department of Integrative Food Bioscience and BiotechnologyChonnam National UniversityGwangju 61186South Korea Department Bioenergy Science and Technology Chonnam National UniversityGwangju 61186South Korea

Protein biogenesis is a complex process,and complexity is greatly increased in eukaryotic cells through specific targeting of proteins to different *** direct targeting,organellar proteins carry an organelle-specific targeting signal for recognition by organelle-specific import ***,the situation is confusing for transmembrane domain(TMD)-containing signalanchored(SA)proteins of various organelles because TMDs function as an endoplasmic reticulum(ER)targeting *** ER targeting of SA proteins is well understood,how they are targeted to mitochondria and chloroplasts remains ***,we investigated how the targeting specificity of SA proteins is determined for specific targeting to mitochondria and *** targeting requires multiple motifs around and within TMDs:a basic residue and an arginine-rich region flanking the N-and C-termini of TMDs,respectively,and an aromatic residue in the C-terminal side of the TMD that specify mitochondrial targeting in an additive *** motifs play a role in slowing down the elongation speed during translation,thereby ensuring mitochondrial targeting in a cotranslational *** contrast,the absence of any of these motifs individually or together causes at varying degrees chloroplast targeting that occurs in a post-translational manner.

关键词： arginine-rich region ER targeting mitochondria targeting organelle targeting TMD translational slowdown transmembrane domain

Assessment of incidental focal colorectal uptake by analysis of fluorine-18 fluorodeoxyglucose positron emission tomography parameters

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World Journal of Clinical Cases 2022年第17期10卷 5634-5645页

作者： haejun Lee Kyung-Hoon hwang Kwang An Kwon Department of Nuclear Medicine Gachon University College of MedicineGil Medical CenterIncheon 21565South Korea Department of Gastroenterology Gachon University College of MedicineGil Medical CenterIncheon 21565South Korea

BACKGROUND Colon and rectal cancers are among the top five cancers worldwide in terms of their incidence and mortality *** the treatment options for cure include surgery even in specific advanced-stage cases,the early detection of lesions is important for applying active treatment ***-18 fluorodeoxyglucose(F-18 FDG)positron emission tomography/computed tomography(PET/CT)is an established imaging study for many types of cancers;however,physiologic uptake in the gastrointestinal tract is a frequent finding and may interfere with lesion ***,as unexpectedly observed focal colorectal F-18 FDG uptake may harbor malignant lesions,further examination must not be *** To assess the clinical implications of unexpected focal colorectal F-18 FDG uptake by analyzing FDG PET *** A total of 15143 F-18 FDG PET/CT scans performed at our hospital between January 2016 and September 2021 were retrospectively reviewed to identify incidentally observed focal colorectal FDG ***,83 regions showing focal colorectal FDG uptake with final histopathological reports from 80 patients(45 men and 35 women with mean ages of 66.9±10.7 years and 63.7±15.3 years,respectively)were eligible for inclusion in the present *** focal hypermetabolic colorectal region was classified as malignant,premalignant,or benign according to the histopathological *** parameters such as maximum and peak standardized uptake value(SUVmax and SUVpeak),metabolic tumor volume(MTV),mean SUV of the metabolic tumor volume(mSUVmtv),and total lesion glycolysis(TLG)were measured or calculated for the corresponding hypermetabolic *** and nonparametric statistical comparisons of these parameters were performed among the three *** operating characteristic curves were plotted to identify cut-off *** The detection rate of incidental focal colorectal uptake was 0.53%(80/15,143).Of the 83 regions with unexpected fo

关键词： Colorectal Incidental Fluorine-18 fluorodeoxyglucose Positron emission tomography/computed tomography Standardized uptake value

Hosting Capacity Evaluation Method for Power Distribution Networks Integrated with Electric Vehicles

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Journal of Modern Power Systems and Clean Energy 2023年第5期11卷 1564-1575页

作者： Wei Dai Cheng Wang Hui hwang Goh jingyi Zhao Jiangyi Jian IEEE School of Electrical Engineering Guangxi UniversityNanning 530000China

The large-scale deployment of electric vehicles(EVs) poses critical challenges to the secure and economic operation of power distribution networks(PDNs). Therefore, a method for evaluating the hosting capacity that enables a PDN to determine the EV chargeable area(EVCA) to satisfy the charging demand and ensure the secure operation is proposed in this paper. Specifically, the distribution system operator(DSO) serves as a public entity to manage the integration of EVs by determining the presence of the charging load in the EVCA. Hence, an EVCA optimization model is formulated on the basis of the coupling effect of the charging nodes to determine the range of the available charging power. In this model, nonlinear power flow equations and operational constraints are considered to maintain the solvability of the power flow of the PDN. Subsequently, a novel multipoint approximation technique is proposed to quickly search for the boundary points of the EVCA. In addition, the impact of the demand response(DR) mechanism on the hosting capacity is explored. The results show that the presence of the DR significantly enlarged the EVCA during peak hours, thus revealing the suitability of the DR mechanism as an important supplement to accommodate the EV charging load. The examined case studies demonstrate the effectiveness of the proposed model and show that the unmanaged allocation of the charging load impedes secure operation. Finally, the proposed method provides a reference for the allocation of the EV charging load and a reduction in the risk of line overloading.

关键词： Capacity evaluation demand response(DR) electric vehicle(EV) electric vehicle chargeable area(EVCA)

gscaLCA in R: Fitting Fuzzy Clustering Analysis Incorporated with Generalized Structured Component Analysis

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Computer Modeling in Engineering & Sciences 2022年第9期132卷 801-822页

作者： Ji Hoon Ryoo Seohee Park Seongeun Kim Heungsun hwang Department of Education College of Educational SciencesYonsei UniversitySeoul03722South Korea Psychometrics Department American Board of Internal MedicinePhiladelphia19016USA Department of Educational Research Methodology School of EducationUniversity of North Carolina at GreensboroGreensboro27412USA Department of Psychology McGill UniversityMontrealH3A 0G4Canada

Clustering analysis identifying unknown heterogenous subgroups of a population(or a sample)has become increasingly popular along with the popularity of machine learning *** there are many software packages running clustering analysis,there is a lack of packages conducting clustering analysis within a structural equation modeling *** package,gscaLCA which is implemented in the R statistical computing environment,was developed for conducting clustering analysis and has been extended to a latent variable *** specifically,by applying both fuzzy clustering(FC)algorithm and generalized structured component analysis(GSCA),the package gscaLCA computes membership prevalence and item response probabilities as posterior probabilities,which is applicable in mixture modeling such as latent class analysis in *** a hybrid model between data clustering in classifications and model-based mixture modeling approach,fuzzy clusterwise GSCA,denoted as gscaLCA,encompasses many advantages from both methods:(1)soft partitioning from FC and(2)efficiency in estimating model parameters with bootstrap method via resolution of global optimization problem from *** main function,gscaLCA,works for both binary and ordered categorical *** addition,gscaLCA can be used for latent class regression as *** of profiles of latent classes based on the posterior probabilities is also available in the package *** paper contributes to providing a methodological tool,gscaLCA that applied researchers such as social scientists and medical researchers can apply clustering analysis in their research.

关键词： Fuzzy clustering generalized structured component analysis gscaLCA latent class analysis

W-translated Schubert divisors and transversal intersections

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Science China Mathematics 2022年第10期65卷 1997-2018页

作者： DongSeon hwang Hwayoung Lee Jae-Hyouk Lee Changzheng Li Department of Mathematics Ajou UniversitySuwon 443-749Republic of Korea Department of Mathematics University of CaliforniaRiversideRiversideCA 92521USA Department of Mathematics Ewha Womans UniversitySeoul 120-750Republic of Korea School of Mathematics Sun Yat-sen UniversityGuangzhou 510275China

We study the toric degeneration of Weyl group translated Schubert divisors of a partial flag variety F?_(n1,...,nk;n) via Gelfand-Cetlin polytopes. We propose a conjecture that Schubert varieties of appropriate dimensions intersect transversally up to translation by Weyl group elements, and verify it in various cases,including the complex Grassmannian Gr(2, n) and the complete flag variety F?_(1,2,3;4).

关键词： W-translated Schubert varieties transversal intersection Gelfand-Cetlin polytope toric degeneration flag varieties

基于类噪声数据的电力系统低频振荡模态参数辨识

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发电技术 2022年第1期43卷 19-31页

作者：闫红艳 hwang jin Kwon 高艳丰河北工程大学水利水电学院河北省邯郸市056038 韩国又石大学能源工程系韩国镇川365-803

低频振荡是影响互联电力系统安全稳定运行的关键问题之一,提出采用变分模态分解(variational mode decomposition,VMD)提取类噪声数据的低频振荡信号,基于离散傅里叶变换(discrete Fourier transform,DFT)曲线拟合的电力系统低频振荡模... 详细信息

低频振荡是影响互联电力系统安全稳定运行的关键问题之一,提出采用变分模态分解(variational mode decomposition,VMD)提取类噪声数据的低频振荡信号,基于离散傅里叶变换(discrete Fourier transform,DFT)曲线拟合的电力系统低频振荡模态辨识方法。首先,采用VMD分解滤除类噪声数据信号中的直流分量,提取出低频振荡信号,利用模态相关系数确定VMD分解个数,提高了信号分解的时效性;其次,建立类噪声数据自回归滑动平均(auto regressive moving average,ARMA)数学模型,模拟产生数据信号,利用低频振荡信号自相关函数的DFT曲线拟合估计拉普拉斯变换系数,提取机电振荡特征参数;最后,采用模拟数据和某实测相量测量单元数据验证了该方法的可行性和有效性。试验表明,采用VMD算法和基于DFT的曲线拟合法提取低频振荡特征参数,有效提高了机电小干扰稳定评估的实时性。

关键词：低频振荡类噪声数据自回归滑动平均(AR‐MA)模型变分模态分解(VMD) 离散傅里叶变换(DFT)曲线拟合

Versatile control of concentration gradients in non-fullerene acceptor-based bulk heterojunction films using solvent rinse treatments

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Green Energy & Environment 2022年第5期7卷 1102-1110页

作者： Chang-Mok Oh Soyeong Jang Jihoon Lee Sung Heum Park In-Wook hwang Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangju61005Republic of Korea Department of Physics Pukyong National UniversityBusan48513Republic of Korea

Solvent rinse treatments using polar methanol(Me OH)and nonpolar n-hexane have been developed for controlling material concentration gradients along the longitudinal direction of non-fullerene acceptor-based bulk heterojunction(BHJ)films comprised of electron donor polymer,PBDB-T and acceptor,*** the used solvents(chlorobenzene with 1 vol%DIO)were completely evaporated,ITIC-m rich domains were formed at the top surface of the BHJ films after they were rinsed with Me OH,as evidenced by water contact angle,atomic force microscopy,time-of-flight secondary ion mass spectroscopy,which led to enhanced electron transport in the conventional structure of organic solar cells(OSCs).In contrast,after rinsing with n-hexane,ITIC-m rich domains were formed at the bottom surface of the films,which improved electron transport in the inverted structure *** enhanced carrier transports increased the PCEs(11.80%and 11.15%)in both conventional and inverted OSCs by 10.29%and 10.35%compared with control *** versatile control of material concentration gradients is determined to be feasible owing to the chemical interaction of the used substrates(glass,PEDOT:PSS,and Zn O)and rinsing solvents.

关键词： films treatment heterojunction