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Toward neglligible memories based heterostructures charge loss in on vertically charge injection integrated 2D

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Nano Research 2016年第8期9卷 2319-2326页

作者： dongri Qiu dong Uk lee Kyoung Su lee Sang Woo Pak Eun Kyu Kim Quantum-Function Research Laboratory and Department of Physics Hanyang University Seou104763 Republic of Korea NAND Development Division NAND Product Engineering Group SK Hynix Icheon 17336 Republic of Korea

Two-dimensional （2D） crystals have a multitude of forms, including semi-metals, semiconductors, and insulators, which are ideal for assembling isolated 2D atomic materials to create van der Waals （vdW） heterostructures. Recently, artificially-stacked materials have been considered promising candidates for nanoelectronic and optoelectronic applications. In this study, we report the vertical integration of layered structures for the fabrication of prototype non-volatile memory devices. A semiconducting-tungsten-disulfide-channel-based memory device is created by sandwiching high-density-of-states multi-layered graphene as a carrier-confining layer between tunnel barriers of hexagonal boron nitride （hBN） and silicon dioxide. The results reveal that a memory window of up to 20 V is opened, leading to a high current ratio （〉103） between programming and erasing states. The proposed design combination produced layered materials that allow devices to attain perfect retention at 13% charge loss after 10 years, offering new possibilities for the integration of transparent, flexible electronic systems.

关键词： two-dimensional (2D)material graphene hexagonal boron nitride(hBN) tungsten disulphide (WS)2 heterostructure

Radar Data Assimilation for the Simulation of Mesoscale Convective Systems

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Advances in Atmospheric Sciences 2010年第5期27卷 1025-1042页

作者： Jo-Han lee Hyun-Ha lee Yonghan CHOI Hyung-Woo KIM dong-Kyou lee School of Earth and Environmental Sciences Seoul National University

A heavy rainfall case related to Mesoscale Convective Systems （MCSs） over the Korean Peninsula was selected to investigate the impact of radar data assimilation on a heavy rainfall forecast. The Weather Research and Forecasting （WRF） three-dimensional variational （3DVAR） data assimilation system with tuning of the length scale of the background error covariance and observation error parameters was used to assimilate radar radial velocity and reffectivity data. The radar data used in the assimilation experiments were preprocessed using quality-control procedures and interpolated/thinned into Cartesian coordinates by the SPRINT/CEDRIC packages. Sensitivity experiments were carried out in order to determine the optimal values of the assimilation window length and the update frequency used for the rapid update cycle and incremental analysis update experiments. The assimilation of radar data has a positive influence on the heavy rainfall forecast. Quantitative features of the heavy rainfall case, such as the maximum rainfall amount and Root Mean Squared Differences （RMSDs） of zonal/meridional wind components, were improved by tuning of the length scale and observation error parameters. Qualitative features of the case, such as the maximum rainfall position and time series of hourly rainfall, were enhanced by an incremental analysis update technique. The positive effects of the radar data assimilation and the tuning of the length scale and observation error parameters were clearly shown by the 3DVAR increment.

关键词： WRF 3DVAR 3DVAR cycling initialization tuning heavy rainfall radar data

SOME PRIMITIVE POLYNOMIALS OVER FINITE FIELDS

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Acta Mathematica Scientia 2001年第3期21卷 412-416页

作者： Seunghwan Chang June bok lee Department of Mathematics, Yonsei University, Seoul 120-749, Korea Yonsei Univ Dept Math Seoul 120749 South Korea

This paper proves that if qn is large enough, for each element a and primitive element b of Fq, there etists a primitive polynomial of degree n ≥5 over the finite field Fq having a as the coefficient of xn-1 and b as the constant term. This proves that if qn is large enongh, for each element a ∈Fq, there exists a primitive polynomial of degree n ≥ 5 over Fq having a as the coefficient of x.

关键词： Finite field primitive polynomial

Complications of common bile duct stones: A risk factors analysis

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Hepatobiliary & Pancreatic Diseases International 2021年第4期20卷 361-365页

作者： dong Jun Oh Ji Hyung Nam dong Kee Jang Jun Kyu lee Department of Internal Medicine Dongguk University Ilsan HospitalGoyang 10326Korea

Background: The latest guidelines recommended that common bile duct stones(CBDSs) should be removed, preferably endoscopically, regardless of the presence of symptoms or complications. However, the removal of CBDSs may not be feasible in very old patients or those with co-morbidities. In these cases, it is important to understand the risk factors for the development of CBDSs-related complications to decide whether or not to treat high-risk patients. Herein, we aimed to identify the risk factors for the development of complications after the diagnosis of CBDSs. Methods: The medical records of patients with CBDSs between October 2005 and September 2019 were retrospectively analyzed. All patients with radiologically-diagnosed CBDSs, including those who received treatment and those who did not, were analyzed. Results: A total of 634 patients were included and 95(15.0%) patients had CBDS-related complications during the mean follow-up period of 32.6 months. Forty-four(6.9%) high-risk patients remained asymptomatic and did not receive treatment during the follow-up period. In multivariate analyses, size of CBDSs ≥ 5 mm and no treatment within 30 days were independent risk factors for the development of complications. The spontaneous passage of CBDSs was proved radiologically in 9 out of 81(11.1%) patients within 30 days. Conclusions: It is recommended treating CBDSs within 30 days from the diagnosis, even in high-risk patients, especially if the size is larger than 5 mm.

关键词： Common bile duct stone Risk factors Obstructive jaundice Pancreatitis Cholangitis

Distribution of Chancelloriids in a Middle Cambrian Carbonate Platform Deposit, Taebaek Group, Korea

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Acta Geologica Sinica(English Edition) 2016年第3期90卷 783-795页

作者： HONG Jongsun CHOH Suk-Joo lee dong-Jin Department of Earth and Environmental Sciences Korea University Department of Earth and Environmental Sciences Andong National University

The onset of the Cambrian witnessed the diversification of ＂small shelly fossils （SSF）＂, which affected carbonate depositional system. One of the problematic SSF, chancelloriids, are common components of the early to middle Cambrian carbonate and shale, and their contributions toward Cambrian carbonates are not yet fully understood. This study assesses distribution patterns of chancelloriid sclerites in the Cambrian Series 3 Daegi Formation based on microfacies analysis and discusses their sedimentologic implications. In the lower part of the formation, partially articulated chancelloriid sclerites occur mainly in bioclastic packstone and grainstone facies, with isolated sclerite rays in nodular packstone to grainstone facies. In the middle part of the formation, chancelloriid fragments occur only sporadically in bioclastic wackestone to packstone, bioclastic grainstone and oolitic packstone to grainstone facies, whereas boundstone facies are nearly devoid of their fragments. There are no chancelloriid fragments in the upper part of the formation, which consists of oolitic packstone to grainstone facies. Chancelloriids are interpreted to have primarily occupied platform margin shoal environments, shedding their sclerites to surrounding areas, and thus contributed as sediment producers. The distribution of Daegi chancelloriid sclerites is similar to other Cambrian examples, with the exception of common chancelloriids in Cambrian Series 2 reefs and their apparent near absence in the Daegi and other Cambrian Series 3 reefs. This disparity resulted from changes in the ecologic niche of chancelloriids after the end-Cambrian Series 2 reef crisis, coupled with an overall decline of chancelloriids in the middle Cambrian.

关键词： Cambrian Series 3 chancelloriid shoal carbonate platform reef

STRESS INTENSITY FACTOR OF AN ANTI-PLANE CRACK PARALLEL TO THE WEAK/MICRO-DISCONTINUOUS INTERFACE IN A BI-FGM COMPOSITE

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Acta Mechanica Solida Sinica 2008年第1期21卷 34-43页

作者： Yong-dong Li Wei Tan Kang Yong lee Department of Mechanical Engineering Academy of Armored Force Engineering No.21 Du Jia Kan Chang Xin Dian Beijing 100072 China School of Mechanical Engineering Yonsei University Seoul 120-749 South Korea

The problem considered is a mode Ⅲ crack lying parallel to the interface of an exponential-type functional graded material （FGM） strip bonded to a linear-type FGM substrate with infinite thickness. By applying the Fourier integral transform, the problem was reduced as a Cauchy singular integral equation with an unknown dislocation density function. The collocation method based on Chebyshev polynomials proposed by Erdogan and Gupta was used to solve the singular integral equation numerically. With the numerical solution, the effects of the geometrical and physical parameters on the stress intensity factor （SIF） were analyzed and the following conclusions were drawn：（a） The region affected by the interface or free surface varies with the material rigidity, and higher material rigidity will lead to bigger affected region. （b） The SIF of the crack in the affected region and parallel to the micro-discontinuous interface is lower than those of the weak discontinuous cases. Reducing the weak-discontinuity of the interface will be beneficial to decrease the SIF of the interface-parallel crack in the region affected by the interface. （c） The effect of the free surface on SIF is more remarkable than that of the interface, and the latter is still more notable than that of the material rigidity. When the effects of the interface and free surface are fixed, increase of the material rigidity will enhance the value of SIF.

关键词： bi-FGM composite mode Ⅲ crack stress intensity factor weak/mico discontinuity,the Cauchy singular integral equation

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

Sodium nitrite-derived nitric oxide protects rat testes against ischemia/reperfusion injury

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Asian Journal of Andrology 2019年第1期21卷 92-97页

作者： Jae Won lee dong-Hun lee Jae Keun Park Jin Soo Han Center for Convergence Bioceramic Materials Korea Institute of Ceramic Engineering and TechnologyChungcheongbuk-do 28160Korea Department of Awan Diseases Laboratory College of Veterinary MedicineKonkuk UniversitySeoul 05029Korea Viral Pathogenesls Section Laboratory of Infectious DiseasesNational Institute of Allergy and infectious DiseasesNational institutes of HealthBethesdaMD 20892USA The institute for the 3Rs & Department of Laboratory Animal Medicine College of Veterinary Medicine and Veterinary Science Research instituteKonkuk UniversitySeoul 05029Korea.

Testicular torsion,a common urologic emergency,is primarily caused by ischemia/reperfusion (I/R)injury of the *** oxide (NO)-derived from nitrite (NO2-)has been reported to have prominent therapeutic effects on I/R injury in the heart,liver,and brain;however,its effects on testicular I/R injury have not been *** study,therefore,investigated whether NO from NO2^-is beneficial in a rat model of testicular I/R injury which eventually results in impaired *** Sprague-Dawley rats were assigned to the following seven groups:group A,sham-operated control group;Group B,I/R with no treatment;Groups C, D,and E,I/R followed by treatment with three different doses of NO2^-;Group F,I/R followed by administration of NO2-and NO scavenger (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide potassium salt [C-PTIO]);and Group G,I/R followed by administration of nitrate (NO3^-).NO2^-,NO3^-,and C-PTIO were intravenously *** examination of the testes and the western blot analysis of caspase-3 were *** of antioxidant enzymes and lipid peroxidation were measured. Germ cell apoptosis,oxidative stress,antioxidant enzymatic function,and lipid peroxidation in Group B were significantly higher than those in Group *** B exhibited an abnormal testicular morphology and impaired *** contrast,testicular damages were attenuated in the NO2^-treatment groups,which were caused by reduction in superoxide and peroxynitrite levels and an inhibition of caspase-3-dependent *** results of this study suggest NO2^-to be a promising therapeutic agent with anti-oxidant and anti-apoptotic properties in testicular I/R injury.

关键词： ischemia/reperfusion injury nitric oxide nitrite rat testis

Cloning of heat shock protein genes from the brown planthopper, Nilaparvata lugens, and the small brown planthopper, Laodelphax striatellus, and their expression in relation to thermal stress

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Insect Science 2008年第5期15卷 415-422页

作者： dong Hun Kim Sang-Chul lee Do-Yeon Kwak Kyeong-Yeoll lee School of Applied Biosciences College of Agricultura and Life Sciences Kyungpook National University Daegu Yeongnam Agricultural Research Institute Milyang Republic of Korea

Three heat shock protein （HSP） genes （hsp70, hsc70, hsp90） were partially cloned from the brown planthopper Nilaparvata lugens and the small brown planthopper Laodelphax striatellus （Homoptera： Delphacidae）, which are serious pests of the rice plant. Sequence comparisons at the deduced amino acid level showed that the three HSPs of planthoppers were most homologous to corresponding HSPs of dipteran and lepidopteran species. Identities of both heat shock cognate 70 and HSP90 were higher than HSP70 in both species. Identity of the HSP70 between the two planthopper species was only 81%, a value much lower than seen among fly and moth groups. Effects of heat and cold shocks were demonstrated on expression of the three hsp genes in the two planthopper species. Heat shock （40 ℃） upregulated the hsp90 level but did not change the hsc70 level in either the nymph and adult stages of either species. On the other hand, the hsp70 level was only upregulated in L. striatellus. This heat shock response was prompt and lasted only for 1 h after treatment. In contrast, cold shock at 4℃ did not change the expression levels of any hsp in either species.

关键词： cold shock gene expression heat shock heat shock protein genes planthoppers thermal stress