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Asian Journal of Andrology 2014年第5期16卷 694-697,I0007页

作者： Jinu lee Dong Ryul lee Suman lee Yonsei Institute of Pharmaceutical Sciences College of Pharmacy Yonsei University Incheon Department of Biomedical Science CHA University Seongnam-si Korea

Monocarboxylic acid transporter 2 （MCT2） transports pyruvate and lactate outside and inside of sperms, mainly as energy sources and plays roles in the regulation of spermatogenesis. We investigated the association among genetic variations in the MCT2 gene, male infertility and MCT2 expression levels in sperm. The functional and genetic significance of the intron 2 （＋28201A 〉 G, rs10506398） and 3＇ untranslated region （UTR） single nucleotide polymorphism （SNP）（＋2626G 〉 A, rs10506399） of MCT2 variants were investigated. Two MCT2 polymorphisms were associated with male infertility （n = 471, P 〈 0.05）. In particular, the MCT2-3＇ UTR SNP （＋2626 G 〉 A） had a strong association with the oligoasthenoteratozoospermia （OAT） group. The ＋2626GG type had an almost 2.4-fold higher sperm count than that of the ＋2626AA type （＋2626GG; 66 x 106 vs ＋2626AA; 27 x 106, P 〈 0.0001）. The MCT2-3＇ UTR SNP may be important for expression, as it is located at the MCT2 3＇ UTR. The average MCT2 protein amount in sperm of the ＋2626GG type was about two times higher than that of the ＋2626AA type. The results suggest that genetic variation in MCT2 has functional and clinical relevance with male infertility.

关键词： 3' UTR male infertility monocarboxylic acid transporter 2 single nucleotide polymorphism sperm

Thin-film PMUTs:a review of over 40 years of research

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Microsystems & Nanoengineering 2023年第4期9卷 1-17页

作者： Kaustav Roy Joshua En-Yuan lee Chengkuo lee Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore Center for Intelligent Sensor and MEMS(CISM) National University of SingaporeSingapore 117608Singapore Institute of Microelectronics A*STARSingapore 117685Singapore

Thin-film PMUTs have been important research topics among microultrasound experts,and a concise review on their research progress is reported *** rigorous surveying,scrutinization,and perception,it has been determined that the work in this field began nearly 44 years ago with the primitive development of functional piezoelectric thin-film *** date,there are three major companies commercializing thin-film PMUTs on a bulk *** commercialization illustrates the extensive contributions made by more than 70 different centers,research institutes,and agencies across 4 different continents regarding the vast development of these devices’design,manufacturing,and *** review covers these important contributions in a short yet comprehensive manner;in particular,this paper educates readers about the global PMUT outlook,their governing design principles,their manufacturing methods,nonconventional yet useful PMUT designs,and category-wise *** comparison charts of thin-film piezoelectric material used in PMUTs,and their categorically targeted applications are depicted and discussed to enlighten any MEMS designer who plans to work with ***,each relevant section features clear future predictions based on the author’s past knowledge and expertise in this field of research and on the findings of a careful literature *** short,this review is a one-stop time-efficient guide for anyone interested in learning about these small devices.

关键词： film piezoelectric companies

Effect of bonding interface on delamination behavior of drawn Cu/Al bar clad material

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中国有色金属学会会刊：英文版 2012年第S3期22卷 645-649页

作者： Sangmok lee Min-Geun lee Sang-Pill lee Geun-Ahn lee Yong-Bae KIM Jong-Sup lee Dong-Su BAE Advanced Forming Technology Center Korea Institute of Industrial Technology Department of Advanced Materials Engineering Dong-Eui University Department of Mechanical Engineering Dong-Eui University

Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat *** these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding *** of Cu/Al interfaces were observed by OM,SEM and EDX Analyser in order to investigate the bonding properties of the *** to the microstructure a series of diffusion layers were observed at the interface and the thicknesses of diffusion layers have increased with aging time as a result of the diffusion *** interfaces were composed of 3-ply diffusion layers and their compositions were changed with aging time at 400 °*** compositional compounds were revealed to be η2,(θ+η2),(α+θ) intermetallic *** is evident from V-notch impact tests that the growth of the brittle diffusion layers with the increasing aging time directly influenced delamination distance between the Cu sleeve and the Al *** is suggested that the proper holding time at 400 °C for aging as post heat treatment of a drawn Cu/Al bar clad material would be within 1 h.

关键词： drawn Cu/Al bar clad material aging bonding interface intermetallic compound diffusion layer delamination

Detection of chemicals in water using a three-dimensional graphene porous structure as liquid-vapor separation filter

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Nano Research 2017年第3期10卷 971-979页

作者： Taekyung Lim Jaejun lee Jonghun lee Sanghyun Ju Department of Physics Kyonggi University Suwon Gyeonggi-Do 443-760 Republic of Korea

In this study, we report the utilization of a three-dimensional （3D） porous graphene structure as liquid-vapor separation filter, which allows the passage of chemical vapors while blocking liquid chemicals and water. The blockage of liquid chemicals and water from semiconducting sensing regions is required to avoid abnormal transistor characteristics. In order to impart omniphobic characteristics, a （heptadecafluoro-1,1,2,2-tetrahydrodecyl）trichlorosilane （HDF-S） self-assembled monolayer was coated on the surface of the 3D porous graphene structure. The concentration of chemical agents in water could be consistently detected by observing the shift in the threshold voltage in the oxide nanowire transistor covered by the HDF-S self-assembled 3D graphene structure. The proposed monitoring method is expected to offer means for application in different environments by providing a stable sensing performance.

关键词： chemical detection graphene structure nanowire transistor self-assembled monolayer omniphobicity

Effects of H_2/CO/CH_4 syngas composition variation on the NO_x and CO emission characteristics in a partially-premixed gas turbine combustor

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Science China(Technological Sciences) 2016年第12期59卷 1804-1813页

作者： lee Min Chul Department of Safety Engineering College of EngineeringFire Disaster Prevention Research CenterIncheon National University

This paper reports the effects of variations in the fuel composition of H_2/CO/CH_4 syngas on the characteristics of NO_x and CO emissions in a partially-premixed gas turbine combustor. Combustion tests were conducted on a full range of fuel compositions by varying each component gas from 0% to 100% at heat inputs of 40 and 50 k Wth. Flame temperature, combustor liner temperature, ignition delay time, and flame structure were investigated computationally and experimentally to judge whether they are significant indicators of NO_x and CO formation. The characteristics of and reasons for NO_x and CO emissions were investigated by analyzing the emission mechanisms and relationships among fuel property, equivalence ratio, flame temperature, liner temperature, flame shape. The flame structures were investigated using the following flame visualization methods:(1) time-averaged OH* chemiluminescence and its Abel-deconvolution;(2) direct photography; and(3) instantaneous OH-PLIF. The flame structures were greatly changed by the fuel composition and heat input, and they were subjected to key affecting parameters of the temperatures of the flames and the liners. NO_x and CO emissions also largely varied according to fuel composition and heat input, showing neither linearly nor exponentially clear proportional trends toward the syngas compositions because of the singular conditions. For example, only the 100% CO flame at low load emitted lots of CO, whereas complete combustion was observed in other cases. However, the qualitative observations showed that the root causes of NO_x emission behaviors were flame temperature and flame structure, which were directly related to the residence time in the flame. Various sets of practical test results were obtained, and these results could contribute to the optimal selection of the fuel-feeding condition when fuel is changed from natural gas to syngas in order to minimize NO_x and CO emissions with stable combustion.

关键词： gas turbine combustor NO_x and CO emission synthetic gas OH* chemiluminescence planar laser induced fluorescence

Interface engineering of an electrospun nanofiber-based composite cathode for intermediate-temperature solid oxide fuel cells

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International Journal of Extreme Manufacturing 2023年第1期5卷 345-353页

作者： Seo Ju Kim Deokyoon Woo Donguk Kim Tae Kyeong lee Jaeyeob lee Wonyoung lee School of Mechanical Engineering Sungkyunkwan UniversitySuwonKyunggi-do 16419Republic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwon 16419Republic of Korea

Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface between the cathode and electrolyte is important for facilitating ORR kinetics and hence improving the electrochemical *** developed the yttria-stabilized zirconia(YSZ)nanofiber(NF)-based composite cathode,where the oxygen vacancy concentration is controlled by varying the dopant cation(Y2O3)ratio in the YSZ *** composite cathode with the optimized oxygen vacancy concentration exhibits maximum power densities of 2.66 and 1.51 W cm^(−2)at 700 and 600℃,respectively,with excellent thermal stability at 700℃ over 500 h under 1.0 A cm^(−2).Electrochemical impedance spectroscopy and distribution of relaxation time analysis revealed that the high oxygen vacancy concentration in the NF-based scaffold facilitates the charge transfer and incorporation reaction occurred at the interfaces between the cathode and *** results demonstrate the high feasibility and potential of interface engineering for achieving IT-SOFCs with higher performance and stability.

关键词： solid oxide fuel cells nanofiber infiltration oxygen reduction reactions oxygen vacancy

Development of mRNA vaccines and their prophylactic and therapeutic applications

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Nano Research 2018年第10期11卷 5173-5192页

作者： Kyuri lee Minjeong Kim Yunmi Seo Hyukjin lee College of Pharmacy Graduate School of Pharmaceutical Sciences Ewha Womans University Seoul 13760 Republic of Korea

Nucleic acid vaccines have attracted enormous attention for resolving the limitations of conventional vaccines using live attenuated viruses. Because nucleic acid vaccines can be produced rapidly in response to the emergence of new virus strains, they are more appropriate for the control of urgent epidemic and pandemic issues. In particular, messenger RNA （mRNA） vaccines have evolved as a new type of nucleic acid vaccines in accordance with their superior protein expression and a lack of mutagenesis as compared with DNA vaccines. Using mRNA vaccines, large amounts of target proteins can be expressed in immune cells for efficient immunization. For instance, antigen-specific vaccination is a feasible option involving the expression of specific antigens in antigen-presenting cells. Immunological reactions are modulated by expressing several proteins associated with stimulation or maturation of immune cells. In addition, mRNA vaccines can stimulate innate immunity through specific recognition by pattern recognition receptors. On the basis of these remarkable properties, mRNA vaccines have been used for prophylactic and therapeutic applications. This review highlights the role of mRNA vaccines as prophylactic vaccines for prevention of future infections and as therapeutic vaccines for cancer immunotherapy. In addition to the conventional type of mRNA vaccines, RNA replicons （self-amplifying mRNA vaccines） will be described.

关键词： messenger RNA (mRNA) vaccines prophylactic vaccines self-amplifying mRNA vaccines therapeutic vaccine cancer immunotherapy

Direct high-resolution X-ray imaging exploiting pseudorandomness

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Light(Science & Applications) 2023年第5期12卷 776-788页

作者： KyeoReh lee Jun Lim Su Yong lee YongKeun Park Department of Physics Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea KAIST Institute for Health Science and Technology Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and TechnologyPohangKyungbuk 37637Republic of Korea Tomocube Inc Daejeon 34051Republic of Korea

Owing to its unique penetrating power and high-resolution capability,X-ray imaging has been an irreplaceable tool since its *** the significance,the resolution of X-ray imaging has largely been limited by the technical difficulties on X-ray lens *** lensless imaging methods have been proposed,but are yet relying on multiple measurements or additional constraints on measurements or *** we present coherent specklecorrelation imaging(CSI)using a designed X-ray *** has no prerequisites for samples or ***,from a single shot measurement,the complex sample field is retrieved based on the pseudorandomness of the speckle intensity pattern,ensured through a *** achieve a spatial resolution of 13.9 nm at 5.46 keV,beating the feature size of the diffuser used(300 nm).The high-resolution imaging capability is theoretically explained based on fundamental and practical *** expect the CSI to be a versatile tool for navigating the unexplored world of nanometer.

关键词： resolution speckle replace

Microstructure and mechanical properties of CoCrFeMnNi high entropy alloy with ultrasonic nanocrystal surface modification process

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Journal of Materials Science & Technology 2020年第22期54卷 123-130页

作者： Timothy Alexander Listyawan Hyunjong lee Nokeun Park Unhae lee School of Materials Science and Engineering Yeungnam University280 Daehak-roCyeongsanGyeongsangbuk-do 38541Republic of Korea Advanced Process and Materials R&D Group Korea Institute of Industrial TechnologyIncheon 21999Republic of Korea Institute of Materials Technology Yeungnam University280 Daehak-roGyeongsanGyeongsangbuk-do 38541Republic of Korea POSCO Technical Research Laboratories Gwangyang 57807Republic of Korea

In this study, mechanical properties improvement of equiatomic CoCrFeMnNi treated with an ultrasonic nanocrystal surface modification(UNSM) was studied. The applied UNSM treatment with static loads of 10 N, 20 N, and 60 N provided a severe plastic deformation, which produced a gradient structure. The nearsurface area exhibited a high number of dislocation densities and deformation twin interaction, leading to a surface strengthening and hardness improvement of up to 112% than the deformation-free interior region. Increment of dislocation densities and deformation twin formation on the surface also enhanced the yield and ultimate tensile strength of the UNSM-treated specimens. Furthermore, the combination of hard nanocrystallites layer on the surface and ductile coarse grain in the specimen interior as a result of the UNSM treatment successfully maintained the strength–ductility balance of the CoCrFeMnNi.

关键词： High-entropy alloy Ultrasonic nanocrystal surface modification Severe plastic deformation Microstructures Mechanical properties

Next High Performance and Low Power Flash Memory Package Structure

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Journal of Computer Science & Technology 2007年第4期22卷 515-520页

作者： Jung-Hoon lee ERI Control Instrumentation EngineeringGyeongSang National UniversityJinju660-701Korea

In general, NAND flash memory has advantages in low power consumption, storage capacity, and fast erase/write performance in contrast to NOR flash. But, main drawback of the NAND flash memory is the slow access time for random read operations. Therefore, we proposed the new NAND flash memory package for overcoming this major drawback. We present a high performance and low power NAND flash memory system with a dual cache memory. The proposed NAND flash package consists of two parts, i.e., an NAND flash memory module, and a dual cache module. The new NAND flash memory system can achieve dramatically higher performance and lower power consumption compared with any conventionM NAND-type flash memory module. Our results show that the proposed system can reduce about 78% of write operations into the flash memory cell and about 70% of read operations from the flash memory cell by using only additional 3KB cache space. This value represents high potential to achieve low power consumption and high performance gain.

关键词： flash memory NAND-type NOR-type memory localities buffer or cache memory