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Influence of CaO on damping capacity and mechanical properties of Mg alloy

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中国有色金属学会会刊：英文版 2009年第B9期19卷 76-79页

作者： Dong-In JANG jin-kyu lee Dae-Up KIM Shae-K KIM Advanced Material Division Korea Institute of Industrial Technology Hyudai Mobis

For developing cost effective damping Mg alloys with high damping capacity and better mechanical properties, the microstructures, the mechanical properties at room temperature and the damping capacity of Mg alloy adding CaO were investigated and compared with those of K1A alloy. CaO adding into pure Mg maintains the damping capacity and increases the ultimate tensile strength compared with those of pure Mg. Mg-CaO alloy can be regarded as cost-effective damping alloy with high damping and mechanical properties as well as with the advantages of improving oxidation and burning resistances.

关键词：阻尼能力力学性能镁合金氧化钙成本效益微观结构阻尼性能电阻合金

A Simple Embedding Method for the Laplace-Beltrami Eigenvalue Problem onImplicit Surfaces

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1189-1216页

作者： Young kyu lee Shingyu Leung Department of Mathematics The Hong Kong University of Science and TechnologyClear Water BayHong KongChina

We propose a simple embedding method for computing the eigenvalues and eigenfunctions of the Laplace-Beltrami operator on implicit *** approach follows an embedding approach for solving the surface eikonal *** replace the differential operator on the interface with a typical Cartesian differential operator in the surface *** proposed algorithm is easy to implement and *** will give some two-and three-dimensional numerical examples to demonstrate the effectiveness of our proposed approach.

关键词： Laplace-Beltrami operator Level set method Implicit representation Eigenvalues Numerical PDEs

Investigation of acoustic attributes based on preference and perceptional acoustics of Korean traditional halls for optimal design solutions

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Building Simulation 2024年第5期17卷 723-738页

作者： Beta Bayu Santika Haram lee jin Yong Jeon Department of Architectural Engineering Hanyang UniversitySeoul 04763R.O.Korea

Immersed in the rich tapestry of traditional culture,Gugak,the traditional Korean music stands as a captivating embodiment of artistic *** study embarked on a comprehensive evaluation of a Gugak hall,employing acoustic measurements,computer simulations,and subjective perception *** evaluation focused on the reverberance,clarity,spatial impression,and preference,unravelling the secrets that shape the immersive Gugak *** intricate computer simulations and auralization,the experience of Gugak performances was meticulously brought to life,allowing exploration under diverse conditions by adjusting stage volume ratios from -20% to+20% and modifying the interior materials,including the walls,ceiling,and lateral *** Gugak halls exhibited relatively low values of reverberation time(RT),early decay time(EDT),and binaural quality index(BQI)the dominant factor influencing the acoustic environment was the effect of sound strength(G).Musical clarity(C80)value did not show an inverse proportionality to the reverberation ***,genre differences between traditional Korean and Western classical music did not significantly affect listeners’perception and satisfaction with regards to reverberance,clarity,and spatial *** a result,Gugak halls can adhere to the same acoustic design criteria as Western orchestra halls,since this study found that people perceived them the same *** this study,sound strength was found to be strongly correlated with perception *** was possible to enhance listeners’perception and preference regarding the acoustic environment through material and structural changes to the sidewalls and *** changes improved the reinforcement of low frequencies and simultaneously enhanced the relative effect of side ***,enhancing the reflection and spatial characteristics of the materials effectively improved listener *** on these findings,an optimal des

关键词： Korean traditional hall acoustical parameters perceptual evaluation acoustic preference stage volume ratio

Acetylacetone-TiO_(2) Promoted Large Area Compatible Cascade Electron Transport Bilayer for Efficient Perovskite Solar Cells

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Energy & Environmental Materials 2024年第2期7卷 221-228页

作者： Hyong Joon lee jin Kyoung Park jin Hyuck Heo Sang Hyuk Im Department of Chemical and Biological Engineering Korea University145 Anam-ro Seongbuk-guSeoul 17104Korea

In designing efficient perovskite solar cells(PSCs),the selection of suitable electron transport layers(ETLs)is critical to the final device performance as they determine the driving force for selective charge ***_(2)nanoparticles(NPs)based ETLs have been a popular choice for PSCs due to superior electron mobility,but their relatively deep-lying conduction band energy levels(ECB)result in substantial potential ***,TiO_(2)NPs establish favorable band alignment owing to shallower ECB,but their low intrinsic mobility and abundant surface trap sites impede the final *** this reason,constructing a cascaded bilayer ETL is highly desirable for efficient PSCs,as it can rearrange energy levels and exploit on advantages of an individual *** this study,we prepare SnO_(2)NPs and acetylacetone-modified TiO_(2)(Acac-TiO_(2))NPs and implement them as bilayer SnO_(2)/Acac-TiO_(2)(BST)ETL,to assemble cascaded energy band ***_(2)contributes to rapid charge carrier transport from high electron mobility while Acac-TiO_(2)minimizes band-offset and effectively suppresses interfacial ***,the optimized BST ETL generates synergistic influence and delivers power conversion efficiency(PCE)as high as 23.14%with open-circuit voltage(V_(oc))reaching 1.14 ***,the BST ETL is transferred to a large scale and the corresponding mini module demonstrates peak performance of 18.39%PCE from 25 cm^(2)aperture ***,the BST-based mini module exhibit excellent stability,maintaining 83.1%of its initial efficiency after 1000 h under simultaneous 1 Sun light-soaking and damp heat(85℃/RH 85%)environment.

关键词： acetylacetone large area perovskite solar cells TiO_(2)

The association between C-reactive protein to albumin ratio and 6-month neurological outcome in patients with in-hospital cardiac arrest

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World Journal of Emergency Medicine 2024年第3期15卷 223-228页

作者： Ji Ho lee Dong Hun lee Byung Kook lee Seok jin Ryu Department of Emergency Medicine Chonnam National University HospitalGwangju 61469Republic of Korea Department of Emergency Medicine Chonnam National University Medical SchoolGwangju 61469Republic of Korea

The global incidence rates of in-hospital cardiac arrest(IHCA)range from1.2 to 9.0 per1,000 hospitalized patients,as per the National Cardiac Arrest Database.[1] While IHCAs tend to exhibit superior 30-day survival rates relative to out-of-hospital cardiac arrests (OHCA) due to situational advantages,such as immediate access to medical personnel and treatments.

关键词： patients cardiac IHC

Intelligent reflecting surface for sum rate enhancement in MIMO systems

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Digital Communications and Networks 2024年第1期10卷 94-100页

作者： Chan-Yeob Park Ji-Sung Jung Yeong-Rong lee Beom-Sik Shin Hyoung-kyu Song Department of Information and Communication Engineering Sejong UniversitySeoulGwangjin-guGunja-dong 98Republic of Korea Department of Convergence Engineering for Intelligent Drone Sejong University SeoulGwangjin-guGunja-dong 98Republic of Korea

The research for the Intelligent Reflecting Surface(IRS)which has the advantages of cost and energy efficiency has been *** capacity can be effectively increased by appropriately setting the phase value of IRS elements according to the channel ***,the problem of obtaining an appropriate phase value of IRs is difficult to solve due to the non-convex *** paper proposes an iterative algorithm for the alternating optimal solution in the Single User Multiple-Input-Multiple-Output(SU-MIMO)*** proposed iterative algorithm finds an alternating optimal solution that is the phase value of IRS one by *** results show that the proposed method has better performance than that of the randomized IRS *** number of iterations for maximizing the performance of the proposed algorithm depends on the channel state between the IRS and the receiver.

关键词： Intelligent reflecting surface MIMO Sum rate

Do brood parasitic Common Cuckoos develop brood patches during the breeding season?

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Avian Research 2024年第3期15卷 363-368页

作者： Jun-Seo Go Hae-Ni Kim Sue-Jeong jin Myeong-Chan Cha Heesoo lee jin-Won lee Korea Institute of Ornithology&Department of Biology Kyung Hee University02447SeoulRepublic of Korea Bird Research SaeZiP 12504YangpyeongRepublic of Korea

Many birds develop brood patches on their ventral apterium under hormonal regulation to effectively transmit body heat to eggs during *** developed patch has several characteristics,including de-feathering,vascularization,and ***,little is known about whether avian brood parasites that do not incubate their eggs exhibit brood patch development during the breeding *** this study,we measured the size of the ventral apterium in 114 Common Cuckoos(Cuculus canorus)captured in the field throughout the breeding season and examined the appearance of the ventral apterium to confirm the development of brood *** also examined whether morphological traits and various factors correlated with the size of the ventral apterium(sternal apterium and abdominal apterium)and how it changed during the breeding *** found no clear signs of brood patch development in Common Cuckoos captured throughout the breeding season,indicating that they likely did not develop brood patches on the ventral apterium during this *** also found that ventral apterium size was positively correlated with wing length and body *** addition,Common Cuckoos with newly growing feathers on the boundary of the ventral apterium with pteryla were frequently observed as seasons progressed to the *** conclusion,Common Cuckoos exhibit neither brood patch development nor the vestigial characteristics of ancestral brood patches,except for the growth of feathers on boundary the ventral *** studies examining brood patches across different groups of avian brood parasites are valuable for enhancing our understanding of the developmental and physiological adaptations of avian brood parasites.

关键词： Brood parasitism Brood patch Common Cuckoo Pterylosis Re-feathering Ventral apterium

Mixed-dimensional stacked nanocomposite structures for a specific wavelength-selectable ambipolar photoresponse

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Nano Research 2024年第6期17卷 5549-5558页

作者： Young Jae Park Jaeho Shim Joo Song lee kyu Seung lee Ji-Yeon Kim Kang Bok Ko Sang-Youp Yim Seongjun Kim Hoon-kyu Shin Donghee Park Yong Ju Yun Dong Ick Son Institute of Advanced Composite Materials Korea Institute of Science and TechnologyJeollabuk-do 55324Republic of Korea National Institute for Nanomaterials Technology Pohang University of Science and TechnologyGyeongsangbuk-do 37673Republic of Korea Department of Semiconductor Science and Technology Semiconductor Physics Research CenterJeonbuk National UniversityJeonju 54896Republic of Korea Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Center for Opto-Electronic Materials and Devices Post-Silicon Semiconductor InstituteKorea Institute of Science and TechnologySeoul 02792Republic of Korea Graduate School of Energy and Environment(KU-KIST Green School) Korea UniversitySeoul 02841Republic of Korea KIST School Department of Nanomaterials and Nano ScienceUniversity of Science and Technology(UST)Daejeon 34113Republic of Korea

Mixed-dimensional composite structures using zero-dimensional(0D)quantum dots(QDs)and two-dimensional(2D)transition metal dichalcogenides(TMDs)materials are expected to attract great interest in optoelectronics due to the potential to generate new optical ***,we report on the unique optical characteristics of a devices with mixed dimensional vertically stacked structures based on tungsten diselenide(WSe_(2))/CdSeS QDs monolayer/molybdenum disulfide(MoS_(2))(2D/0D/2D).Specifically,it exhibits an ambipolar photoresponse characteristic,with a negative photoresponse observed in the 400-600 nm wavelength range and a positive photoresponse appeared at 700 nm *** resulted in the high negative responsivity of up to 52.22 mA·W^(−1)under 400 nm,which is 163 times higher than that of the photodetector without CdSeS *** also demonstrated the negative photoresponse,which could be due to increased carrier collision probability and non-radiative *** modeling and simulation reveal that Auger recombination among the types of non-radiative recombination is the main cause of negative photocurrent ***,we discovered ambipolar photoresponse near a specific wavelength corresponding to the energy of quantum *** study revealed interesting phenomenon in the mixed low-dimensional stacked structure and paved the way to exploit it for the development of innovative photodetection materials as well as for optoelectronic applications.

关键词： mixed-dimension quantum dot heterostructure photodetector ambipolar photoresponse

Vertical plane depth-resolved surface potential and carrier separation characteristics in flexible CZTSSe solar cells with over 12% efficiency

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Carbon Energy 2024年第3期6卷 36-52页

作者： Dae-Ho Son Ha kyung Park Dae-Hwan Kim jin-kyu Kang Shi-Joon Sung Dae-Kue Hwang Jaebaek lee Dong-Hwan Jeon Yunae Cho William Jo Taeseon lee JunHo Kim Sang-Hoon Nam Kee-Jeong Yang Division of Energy Technology DGISTDaeguRepublic of Korea Research Center for Thin Film Solar Cells DGISTDaeguRepublic of Korea Department of Physics Ewha Womans UniversitySeoulRepublic of Korea Department of Physics Incheon National UniversityIncheonRepublic of Korea Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMassachusettsUSA

Cu2ZnSn(S,Se)4(CZTSSe)solar cells have resource distribution and economic *** main cause of their low efficiency is carrier loss resulting from recombination of photo-generated electron and *** overcome this,it is important to understand their electron-hole behavior *** determine the carrier separation characteristics,we measured the surface potential and the local current in terms of the absorber *** elemental variation in the intragrains(IGs)and at the grain boundaries(GBs)caused a band edge shift and bandgap(Eg)*** the absorber surface and subsurface,an upward Ec and Ev band bending structure was observed at the GBs,and the carrier separation was *** the absorber center,both upward Ec and Ev and downward Ec-upward Ev band bending structures were observed at the GBs,and the carrier separation was *** improve the carrier separation and suppress carrier recombination,an upward Ec and Ev band bending structure at the GBs is desirable.

关键词： carrier separation CZTSSe flexible solar cell local current surface potential