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Revealing the inhomogeneous surface chemistry on the spherical layered oxide polycrystalline cathode particles

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Chinese Physics B 2020年第2期29卷 81-86页

作者： Zhi-Sen Jiang Shao-Feng Li Zheng-Rui Xu Dennis Nordlund Hendrik Ohldag Piero Pianetta jun-sik lee Feng Lin Yi-Jin Liu College of Physics Sichuan UniversityChengdu 610065China Stanford Synchrotron Radiation Lightsource SLAC National Accelerator LaboratoryMenlo ParkCA 94025USA Department of Chemistry Virginia TechBlacksburgVA 24061USA

The hierarchical structure of the composite cathodes brings in significant chemical complexity related to the interfaces,such as cathode electrolyte *** interfaces account for only a small fraction of the volume and mass,they could,however,have profound impacts on the cell-level *** the investigation of these interfaces becomes a crucial topic in the battery research,there is a need to properly study the surface chemistry,particularly to eliminate the biased,incomplete characterization provided by techniques that assume the homogeneous surface ***,we utilize nano-resolution spatially-resolved x-ray spectroscopic tools to probe the heterogeneity of the surface chemistry on LiNi0.8Mn0.1Co0.1O2 layered cathode secondary *** by the nano-resolution mapping of the Ni valance state,which serves as a measurement of the local surface chemistry,we construct a conceptual model to elucidate the electrochemical consequence of the inhomogeneous local impedance over the particle *** beyond the implication in battery science,our work highlights a balance between the high-resolution probing the local chemistry and the statistical representativeness,which is particularly vital in the study of the highly complex material systems.

关键词： Ni-rich cathode x-ray nanoprobe redox heterogeneity surface chemistry

Quantitative analysis of mechanical properties associated with aging treatment and microstructure in Mg-Al-Zn alloys through machine learning

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Journal of Materials Science & Technology 2022年第12期107卷 52-63页

作者： Joung sik Suh Byeong-Chan Suh Sang Eun lee jun Ho Bae Byoung Gi Moon Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

The present study proposes a methodology for predicting the mechanical properties of AZ61 and AZ91alloys associated with microstructure,texture and aging parameters and estimating predictor *** this,we investigate quantitative correlations between microstructure,texture and mechanical properties of aged AZ61 and AZ91 rods through machine *** regression analysis focuses on the precipitation behavior of Mg17Al12as the main second phase of Mg-Al-Zn alloys with respect to aging *** simplify data generation,only SEM images were used to quantify the features of discontinuous and continuous *** overcome the lack of data and make the most of the measured data,we devised a method to extend the existing dataset by a factor of 9 using the mean and standard deviation of the measured *** neural networks predicted tensile and compressive yield strengths and resultant yield asymmetry with a high accuracy of over 98%using 11 predictors for a total of *** tree learning quantitatively assessed the importance of predictors in determining the mechanical properties of aged AZ61 and AZ91 rods.

关键词： Magnesium alloy Aging treatment Microstructure Mechanical properties Machine learning

Effect of Ni and Mn on the Mechanical Properties of 22Cr Microduplex Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2015年第1期28卷 32-38页

作者： jun-Young Park Yong-sik Ahn Department of Materials Science and Engineering Pukyong National University

The tensile properties of 22Cr–2Ni–4Mn–0.2N micro-duplex stainless steels with different Ni and Mn contents were investigated. Duplex stainless steels were vacuum induction melted and hot rolled, then annealed at 1,000–1,100 °C, at which temperature both the austenite and ferrite phases were stable. The volume fraction of the ferrite phase was markedly affected by the alloying elements of Mn and Ni; 1 wt% of Mn was equivalent to 0.4 wt% of Ni. All of the steels tested at room temperature showed the common strain-hardening behavior, while the steels tested at lower temperatures（-30 or-50 °C）showed a distinct inflection point in their stress–strain curves, which resulted from the transformation of the austenite to straininduced martensite. The onset strain（e0） of the inflection point in the stress–strain curve depended on the Md30 value of the steel. Testing at lower temperatures resulted in smaller e0 and consequently higher strengths and fracture strains（ef）. The tensile behavior was examined from the perspective of austenite stability of the micro-duplex stainless steels with the different Ni and Mn contents.

关键词： Duplex stainless steel Microstructure Mechanical property Alloy composition

Estimation of genetic parameters on growth characteristics of a 35-year-old Pinus koraiensis progeny trial in South Korea

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Journal of Forestry Research 2021年第5期32卷 2227-2236页

作者： Kyungmi lee In sik Kim Seok Woo lee Division of Forest Tree Improvement Department of Forest BioresourcesNational Institute of Forest ScienceSuwonRepublic of Korea

The effects of genetic and environmental factors on Pinus koraiensis growth were studied based on a35 year-old progeny trial composed of open-pollinated offspring of twenty-one plus ***,DBH and volume of the offspring was analyzed using restricted maximum likelihood/best linear unbiased prediction in mixed model *** site and family effects on the three traits were *** distinct growth of offspring by site with disparate climates corroborated the importance of planting species in suitable *** differences by family was significant,emphasizing the importance of identifying families with either superior or inferior *** parental ranking was assigned in the sites,inferring the breeding value of each plus *** estimates of individual heritability(h_(i)^(2))of height,DBH and volume growth were 0.169-0.645,0.108-0.331 and 0.129-0.343 respectively,with higher h_(i)^(2) of the height than DBH on each *** of variance of genetic effect was higher with DBH in some cases,indicating the scope for selection is larger for this trait despite the lower heritability compared to *** the variation between families in terms of the performance stability across sites,consideration of the genotype by environment interaction is required in selecting materials to be used in reforestation with Korean pine.A few families with either superior or inferior performance retained their parental ranking for at least a *** families with increased growth on a particular site were identified,indicating their high breeding value and low *** in the genetic performance of the families by site requires delineation of the breeding region of the species.

关键词： Pinus koraiensis Genetic parameters Genotype by environment interaction Tree improvement Progeny trial

A hybrid storage technology for low power consumption and high I/O performance in an IPTV set-top box

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Journal of Central South University 2012年第5期19卷 1267-1275页

作者： KIM Deok-hwan YANG jun-sik Department of Electronics Engineering Inha UniversityIncheon 402-751Korea

A new method of prefetching data blocks from the NVCache to the page cache in main memory and cascading prefetching n-blocks from a hard disk to the NVCache together was proposed to reduce the spin-up frequency of a hybrid hard disk drive and thus enhance I/O *** proposed method consists of three steps:1) Analyzing the pattern of read requests in block units;2) Determining the number of blocks prefetched to the NVCache;3) Replacing blocks in the NVCache according to the block replacement *** proposed method can reduce the latency time of a hybrid hard disk and optimize the power consumption of an IPTV set-top *** results show that the proposed method provides better average response time compared to an existing adaptive multistream prefetching(AMP) method by 25.17%.It also reduces by 20.83% the average power consumption over that of the existing external caching in energy saving storage system(EXCES) method.

关键词： IPTV set-top box hybrid hard disk prefetching spin-down low power consumption

Speech enhancement through voice activity detection using speech absence probability based on Teager energy

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Journal of Central South University 2013年第2期20卷 424-432页

作者： PARKYun-sik lee Sang-min Department of Electronic Engineering Inha University Institute for Information and Electronics Research Inha University

In this work, a novel voice activity detection （VAD） algorithm that uses speech absence probability （SAP） based on Teager energy （TE） was proposed for speech enhancement. The proposed method employs local SAP （LSAP） based on the TE of noisy speech as a feature parameter for voice activity detection （VAD） in each frequency subband, rather than conventional LSAP. Results show that the TE operator can enhance the abiTity to discriminate speech and noise and further suppress noise components. Therefore, TE-based LSAP provides a better representation of LSAP, resulting in improved VAD for estimating noise power in a speech enhancement algorithm. In addition, the presented method utilizes TE-based global SAP （GSAP） derived in each frame as the weighting parameter for modifying the adopted TE operator and improving its performance. The proposed algorithm was evaluated by objective and subjective quality tests under various environments, and was shown to produce better results than the conventional method.

关键词： speech enhancement Teager energy speech absence probability voice activity detection

Synthesis and microstructure of zirconia nanopowders by glycothermal processing

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中国有色金属学会会刊：英文版 2009年第B9期19卷 88-91页

作者： jun-Seop KIM Dong-Hae lee Sung KANG Dong-sik BAE Hoy-Yul PARK Moon-Kyeung NA School of Nano & Advanced Material Engineering College of EngineeringChangwon National University Advanced Materials and Application Research Laboratory Korea Electro Technology Research Institute

ZrO2 nanoparticles were prepared under high temperature and high pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. The effects of synthesis parameters, such as the concentration of starting solution, pH of starting solution, reaction temperature and time, were discussed. The results show that the ZrO2 nanoparticles are obtained at 230-270 ℃. The average size and size distribution of the synthesized particles are below 10 nm and narrow, respectively. The XRD pattern shows that the synthesized particles are composed of crystalline. The synthesis of ZrO2 nanosized crystalline particles is possible under glycothermal conditions in ethylene glycol solution.

关键词：纳米氧化锆合成粉体加工微观结构结晶颗粒溶液pH值高压条件氢氧化钾

Degenerate s-Extended Complete and Incomplete Lah-Bell Polynomials

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Computer Modeling in Engineering & Sciences 2022年第6期130卷 1479-1495页

作者： Hye Kyung Kim Dae sik lee Department of Mathematics Education Daegu Catholic UniversityGyeongsan38430Korea School of Electronic and Electric Engineering Daegu UniversityGyeongsan38453Korea

Degenerate versions of special polynomials and numbers applied to social problems,physics,and applied mathematics have been studied variously in recent ***,the(s-)Lah numbers have many other interesting applications in analysis and *** this paper,we divide two *** first introduce new types of both degenerate incomplete and complete s-Bell polynomials respectively and investigate some properties of them ***,we introduce the degenerate versions of complete and incomplete Lah-Bell polynomials as multivariate forms for a new type of degenerate s-extended Lah-Bell polynomials and numbers *** investigate relations between these polynomials and degenerate incomplete and complete s-Bell polynomials,and derive explicit formulas for these polynomials.

关键词： Lah-Bell numbers and polynomials s-extended Lah-Bell numbers and polynomials complete s-Bell polynomials incomplete s-Bell polynomials s-Stirling numbers of second kind

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