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Selective Growth of ZnO Nanorods on SiO2/Si Substrates Using a Graphene Buffer Layer

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Nano Research 2011年第5期4卷 440-447页

作者： Won Mook Choi Kyung-sik Shin Hyo Sug Lee Dukhyun Choi Kihong kim Hyeon-Jin Shin Seon-Mi Yoon Jae-young Choi Sang-Woo kim Samsung Advanced Institute of Technology Giheung Yongin Gyeonggi 446-712 Republic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan （SKKU） Advanced Institute of Nanotechnology （SAINT） Center for Human Interface Nanotechnology （HINT） Sungkyunkwan University Suwon 440-746 Republic of Korea Department of Mechanical Engineering Kyung Hee University Yongin Gyeonggi 446-701 Republic of Korea

A promising strategy for the selective growth of ZnO nanorods on SiO2/Si substrates using a graphene buffer layer in a low temperature solution process is described. High densities of ZnO nanorods were grown over a large area and most ZnO nanorods were vertically well-aligned on graphene. Furthermore, selective growth of ZnO nanorods on graphene was realized by applying a simple mechanical treatment, since ZnO nanorods formed on graphene are mechanically stable on an atomic level. These results were confirmed by first principles calculations which showed that the ZnO-graphene binding has a low destabilization energy. In addition, it was found that ZnO nanorods grown on SiO2/Si with a graphene buffer layer have better optical properties than ZnO nanorods grown on bare SiO2/Si. The nanostructured ZnO-graphene materials have promising applications in future flexible electronic and optical devices.

关键词： Graphene ZnO nanorod heterojunction selective growth solution

Data Aggregation-based Transmission Method in Ultra-Dense Wireless Networks

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Intelligent Automation & Soft Computing 2023年第1期35卷 727-737页

作者： Dae-young kim Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea

As the Internet of Things(IoT)advances,machine-type devices are densely deployed and massive networks such as ultra-dense networks(UDNs)are *** devices attend to the network to transmit data using machine-type communication(MTC),whereby numerous,various are *** devices generally have resource constraints and use wireless *** this kind of network,data aggregation is a key function to provide transmission *** can reduce the number of transmitted data in the network,and this leads to energy saving and reducing transmission *** order to effectively operate data aggregation in UDNs,it is important to select an aggregation point *** total number of transmitted data may vary,depending on the aggregation point to which the data are ***,in this paper,we propose a novel data aggregation scheme to select the appropriate aggregation point and describe the data transmission method applying the proposed aggregation *** addition,we evaluate the proposed scheme with extensive computer *** performances in the proposed scheme are achieved compared to the conventional approach.

关键词： Data aggregation data transmission ultra-dense network machine-type communication Internet of Things

Absence of enhancement in a lesion does not preclude primary central nervous system T-cell lymphoma:A case report

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World Journal of Clinical Cases 2024年第2期12卷 374-382页

作者： Chan-Seop kim Chi-Hoon Choi Kyung sik Yi Yook kim Jisun Lee Chang Gok Woo young Hun Jeon Department of Radiology Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea Department of Pathology Chungbuk National University HospitalChungbuk National University College of MedicineCheongju-si 28644Chungcheongbuk-doSouth Korea Department of Radiology Seoul National University HosptialSeoul 03080South Korea

BACKGROUND Primary central nervous system lymphoma(PCNSL)is a non-Hodgkin lymphoma that originates in the central nervous system(CNS)and is exclusively limited to the *** most PCNSLs are diffuse large B-cell lymphomas,primary CNS T-cell lymphomas(PCNSTLs)are *** typically demonstrate some degree of enhancement on contrast-enhanced magnetic resonance imaging(MRI).To the best of our knowledge,non-enhancing PCNSTL has not been reported *** SUMMARY A 69-year-old male presented to the neurology department with complaints of mild cognitive impairment and gradual onset of left lower leg weakness over a span of two *** MRI showed asymmetric T2-hyperintense lesions within the *** enhancement was observed on the contrast-enhanced T1 *** initial diagnosis was neuro-Behçet’s *** high-dose steroid therapy,no alterations in the lesions were identified on initial *** patient’s symptoms deteriorated *** MRI performed one month after the initial scan revealed an increased lesion ***,brain biopsy confirmed the diagnosis of *** patient underwent definitive combined ***,the patient developed bacteremia and died of septic shock approximately three months after *** The absence of enhancement in the lesion did not rule out PCNSTL.A biopsy approach is advisable for pathological confirmation.

关键词： Central nervous system neoplasms Non-Hodgkin Lymphoma T-cell Lymphoma Primary central nervous system lymphoma Primary central nervous system T-cell lymphoma Case report

High-temperature Oxidation Behavior of Zircaloy-4 and Zirlo in Steam Ambient

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Journal of Materials Science & Technology 2010年第9期26卷 827-832页

作者： Hyung Hoon kim Jun Ho kim Jin young Moon Ho Seong Lee Jeong Joo kim young Suck Chai School of Materials Science and Engineering Kyungpook National University School of Mechanical Engineering Yeungnam University214-1 Dae-dongGyeongsan-si

The oxidation characteristics for Zircaloy-4 and Zirlo in the temperature range of 700-1200°C under steam supply condition were investigated by using a modified thermo-gravimetric *** specimens were oxidized for 3600 s at each temperature and then quenched in a *** oxidation rate constants were measured from the weight gains to evaluate the oxidation behavior in Zircaloy-4 and *** weight gain rates of Zirlo were lower than those of Zircaloy-4,leading to the low rate *** different oxidation behaviors between both cladding materials were considered to be due to the difference in their chemical compositions.

关键词： Zircaloy-4 Zirlo Oxidation

LoRa Backscatter Network Efficient Data Transmission Using RF Source Range Control

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Computers, Materials & Continua 2023年第2期74卷 4015-4025页

作者： Dae-young kim SoYeon Lee Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea Department of Software Convergence Soonchunhyang UniversityAsan31538Korea

Networks based on backscatter communication provide wireless data transmission in the absence of a power source.A backscatter device receives a radio frequency(RF)source and creates a backscattered signal that delivers data;this enables new services in battery-less domains with massive Internet-of-Things(IoT)*** is highly energy-efficient in the context of massive IoT ***,long-range(LoRa)backscattering facilitates large IoT services.A backscatter network guarantees timeslot-and contention-based ***-based transmission ensures data transmission,but is not scalable to different numbers of transmission *** contention-based transmission is used,collisions are *** reduce collisions and increase transmission efficiency,the number of devices transmitting data must be *** control device activation,the RF source range can be modulated by adjusting the RF source power during LoRa *** reduces the number of transmitting devices,and thus collisions and retransmission,thereby improving transmission *** performed extensive simulations to evaluate the performance of our method.

关键词： Backscatter communication LoRa backscatter RF source range control activated device control internet of things

Comparison of mesophilic and thermophilic anaerobic digestions of thermal hydrolysis pretreated swine manure: Process performance,microbial communities and energy balance

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Journal of Environmental Sciences 2023年第4期126卷 222-233页

作者： Xiaohui Liu Changmin Lee Jae young kim Department of Civil and Environmental Engineering Seoul National UniversitySeoul 08826Korea

Anaerobic digestion (AD) of swine manure (SM) commonly shows low biogas output and unsatisfactory economic performance. In this study, thermophilic AD (TAD, 50±1℃) was combined with thermal hydrolysis pretreatment (THP, 170℃/10 bar), to investigate its potential for maximizing biogas yield, securing successful digestion and microbial diversity, as well as improving energy balance. Four lab-scale continuously stirred tank reactors were operated for 300 days and compared with each other, i.e., reactor 1 (raw SM fed in mesophilic AD:RSM-MAD), reactor 2 (THP-treated SM fed in MAD:TSM-MAD), reactor 3 (RSM-TAD),and reactor 4 (TSM-TAD). The results showed that THP was efficient to increase methane production of SM, TSM-TAD mode led to the highest methane yield (129.8±40.5 mL-CH_(4)/gVS/day) among the tests (p 700 mg/L) or volatile fatty acids (> 6000 mg/L) accumulation compared with MAD in start-up phase, TSM-TAD treatment mode behaved a sustainable digestion process in a long-term operation. For TSM-TAD scenario, higher Shannon–Weaver (3.873) and lower Simpson index (0.061) indicated this mode ensured and enlarged the diversity of bacteria communities. Phylum Bathyarchaeota was dominant (59.3%-90.0%) in archaea community,followed by Euryarchaeota in the four reactors. RSM-MAD treatment mode achieved the highest energy output (4.65 GJ/day), TSM-TAD was less effective (-17.38 GJ/day) due to increased energy demands. Thus improving the energetic efficiency of THP units is recommended for the development of TSM-TAD treatment mode.

关键词： Thermal hydrolysis pretreatment Digestion temperature Process performances Microbial communities Energy balance

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World Journal of Gastroenterology 2014年第40期20卷 14581-14588页

作者： Hwi young kim Won kim Division of Gastroenterology and Hepatology Department of Internal Medicine Seoul Metropolitan Government-Seoul National University Boramae Medical Center Seoul 156-707 South Korea

Hepatitis B reactivation is a potentially serious complication of anticancer chemotherapy,which occurs during and after *** condition affects primarily hepatitis B surface antigen(HBsAg)-positive patients,but sometimes HBsAg-negative patients can be at risk,based only on evidence of past infection or occult infection with a low titer of detectable hepatitis B virus(HBV)*** clinical outcomes vary with the different degrees of virologic and biochemical rebound,ranging from asymptomatic elevations in liver enzymes to hepatic failure and even *** the remarkable advancement in the treatment of chronic hepatitis B over the past decade,proper strategies for the prevention and management of HBV reactivation remain ***,with the increasing use of rituximab in patients with lymphoma,HBV reactivation in occult or past infections has become increasingly problematic,especially in HBV-endemic *** review addresses the current knowledge on the clinical aspects and management of chemotherapy-related HBV reactivation,updates from recent reports,several unresolvedissues and future perspectives.

关键词： Hepatitis B virus Chemotherapy Reactivation

Biomimetic Quadruped Robot with a Spinal Joint and Optimal Spinal Motion via Reinforcement Learning

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Journal of Bionic Engineering 2021年第6期18卷 1280-1290页

作者： young Kook kim Woojin Seol Jihyuk Park LV R&D Team Electro-technology R&D CenterLS Electric Co.LtdCheongju28437Republic of Korea Digital Innovation Unit Korea Hydro&Nuclear Power Co.Ltd1312-gil YuseongdaeroYusung-guDaejeon34101Republic of Korea Department of Automotive Engineering College of Mechanical and IT EngineeringYeungnam University280 Daehak-roGyeongsanGyeongbuk38541Republic of Korea

Feline animals can run quickly using spinal joints as well as the joints that make up their four *** paper describes the development of a quadruped robot including a spinal joint that biomimics feline *** developed robot platform consists of four legs with a double 4-bar linkage type and one simplified rotary *** addition,Q-learning,a type of machine learning,was used to find the optimal motion profile of the spinal *** bounding gait was implemented on the robot system using the motion profile of the spinal joint,and it was confirmed that using the spinal joint can achieve a faster Center of Mass(CoM)forward speed than not using the spinal *** the motion profile obtained through Q-learning did not exactly match the spinal angle of a feline animal,which is more multiarticular than that of the developed robot,the tendency of the actual feline animal spinal motion profile,which is sinusoidal,was similar.

关键词： Quadruped robot system Bioinspired methods Legged robots Machine learning Q-learning

A unified formulation of optimal guidance-to-collision law for accelerating and decelerating targets

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Chinese Journal of Aeronautics 2022年第7期35卷 40-54页

作者： young-Won kim Boseok kim Chang-Hun LEE Shaoming HE Department of Aerospace Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

This paper provides a unified formulation of optimal guidance-to-collision law for a target with an arbitrary acceleration or *** collision course for general target acceleration or deceleration is first determined from the engagement geometry in conjunction with the nonlinear engagement kinematics in the proposed *** heading error defined in the collision course is then adopted as a variable to be nullified for accomplishing the intercept *** proposed guidance law is derived based on the heading error dynamics and the optimal error dynamics to ensure optimality and finite-time *** illustrative examples,the proposed guidance command for a constant target acceleration and a target deceleration in the form of a quadratic function of speed are ***,the time-to-go prediction method is suggested for implementing the proposed *** characteristics of the proposed guidance command are analytically investigated to provide insight into the proposed *** key benefits of the proposed method lie in not producing unnecessary guidance commands near a target compared to other methods and ensuring optimality in guidance command even in the nonlinear engagement ***,numerical simulations are performed to validate the proposed method and to show our findings.

关键词： Guidance-to-collision law Optimal guidance Optimal error dynamics Target acceleration or deceleration Unified formulation