http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Splenic Autotransplantation after Blunt Spleen Injury in Children
( Hojun Lee ),( Byung Hee Kang ),( Junsik Kwon ),( John Cook-jong Lee ) 대한외상학회 2018 大韓外傷學會誌 Vol.31 No.2
Non-operative management has been preferred in blunt spleen injury. Moreover children are more susceptible to post-splenectomy infection, spleen should be preserved if possible. However, splenectomy is inevitable to patients with severe splenic injury. Therefore splenic autotransplantation could be the last chance for preserving splenic function in these patients although efficacy has not proven. Here we reported four cases of children who were underwent splenic autotransplantation successfully after blunt trauma.
Ridge-following control for agricultural tractors using deep learning and stereo camera
Hojun Kang,Dongoh Seo,Beomjin Lee,Jong-Gyu Han,Jun-Hee Jo,Mooncheol Won 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7
The furrow irrigation, which forms a ridge-furrow and grows several crops on the ridge, involves the seeding work using the tractor that follows the path of the ridge. This work requires long hours labor from human, and there is a possibility that the work efficiency may decrease. In this paper, we propose deep learning and stereo image-based algorithms for sowing tasks on ridges via autonomous path-following of the tractor. The collected stereo image is converted into a depth image through a matching algorithm, and the depth image is input to a MobileNetV2-based deep learning network model to obtain a center line of the ridge. In addition, the target value of steering angle control is calculated by waypoint preview control concept. so that the tractor can follow the estimated center line of the ridge. The proposed algorithm is verified by GPS-based path information of autonomous driving and comparing it with human-operated driving path.
Orthogonal Waveform Space Projection Method for Adaptive Jammer Suppression
Kang-In Lee,Hojun Yoon,Jongmann Kim,Young-Seek Chung 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2
In this paper, we propose a new jammer suppression algorithm that uses orthogonal waveform space projection (OWSP) processing for a multiple input multiple output (MIMO) radar system exposed to a jamming signal. Generally, a conventional suppression algorithm based on adaptive beamforming (ABF) needs a covariance matrix composed of the jammer and noise only. By exploiting the orthogonality of the transmitting waveforms of MIMO, we can construct a transmitting waveform space (TWS). Then, using the OWSP processing, we can build a space orthogonal to the TWS that contains no SOI. By excluding the SOI from the received signal, even in the case that contains the SOI and jamming signal, the proposed algorithm makes it possible to evaluate the covariance matrix for ABF. We applied the proposed OWSP processing to suppressing the jamming signal in bistatic MIMO radar. We verified the performance of the proposed algorithm by comparing the SINR loss to that of the ideal covariance matrix composed of the jammer and noise only. We also derived the computational complexity of the proposed algorithm and compared the estimation of the DOD and DOA using the SOI with those using the generalized likelihood ratio test (GLRT) algorithm.
ReRAM 소자의 비정질물질 Ag도핑에 따른 특성 향상에 대한 연구
김강(Kang Kim),이호준(Hojun Lee) 산업기술교육훈련학회 2021 산업기술연구논문지 (JITR) Vol.26 No.2
The most popular devices in next-generation computer memory technology are the phase change RAM (PRAM), nano-floating gate memory (NFGM), resistance RAM (ReRAM), polymer RAM (PoRAM), magnetic RAM (MRAM), and molecular electronic devices. Amongst these, ReRAM is the most-researched candidate for nonvolatile memory technologies due to its simple metal-insulator-metal (MIM) structure and excellent operational characteristics. However, it faces obstacles such as high production costs and insufficient uniformity. This study aims to tackle the latter problem by spin-coating Ag nanoparticles on the upper electrode to improve the uniformity characteristics.
Ryu, Hojun,Kim, Jisoo,Kim, Jongkuk,Kim, Do Hyun,Kang, Yong-Jin,Jang, Young-Jun,Jeong, Ji Hwan Elsevier 2020 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER - Vol.148 No.-
<P><B>Abstract</B></P> <P>Dropwise condensation (DWC) is one of the most important phenomena to improve the heat transfer performance of steam condensation system. To promote DWC on hydrophilic metals, non-metallic hydrophobic promoters are coated on the surface. Non-metallic coatings are relatively easy to be degraded due to lack of mechanical and chemical properties. In this study, fluorine-doped diamond-like carbon (F-DLC) was used to obtain DWC on Al6061. Prior to F-DLC coating, microtextures were fabricated on Al6061 for the structural wettability control. DWC was successfully obtained with a small size of condensates after the microblasting and nanostructured F-DLC coating on Al6061. The synergic effects of microtextures with Cassie-state contact angle and hydrophobicity of nanostructured F-DLC led the superhydrophobic transformation of the surface. The contact angle increased about 115% from 66° to 142° after the microblasting and nanostructured F-DLC coating. The resulting DWC improved heat transfer performance of Al6061 significantly, 205%, as the dropwise condensates were rapidly eliminated from the surface. The variations on contact angle hysteresis before and after the steam condensation analysis revealed that the superhydrophobicity and DWC mode can be stably maintained under the steam condensing conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fabrication of the superhydophobic surface to improve the heat transfer resistance was proposed using the microblasting and nanostructured F-DLC coating. </LI> <LI> Microtextures fabricated by the microblasting induced Cassie-state contact angle on Al6061 surface. </LI> <LI> Nanostructured F-DLC coating led the transformation of condensation mode from FWC to DWC. </LI> <LI> The heat transfer efficiency in the steam condensation system was improved 205% on average following the transformation to DWC mode. </LI> <LI> The stable contact angle hysteresis before and after the steam condensation analysis specified the durability of nanostructured F-DLC coating under steam condensing environment. </LI> </UL> </P>
이온교환막 연료전지용 원통형 막 가습기의 열 및 물질전달특성 기초 연구
배호준(Hojune Bae),안국영(Kook Young Ahn),이영덕(Young Duk Lee),강상규(Sang Kyu Kang),유상석(Sangseok Yu) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.5
막 가습기는 다른 가습장치와는 달리, 기생 전력의 손실이 없고 가습 성능이 우수하여 이온교환막 연료전지의 외부 가습을 위해 적용되고 있다. 원통형 막 가습기는 특히 가습성능에 비해 요구 체적이 매우 작기 때문에, 수송용 및 가정용 이온교환막 연료전지에 적용된다. 막가습기의 최적 설계를 위한 열 및 물질 전달 특성에 대한 이해가 필요하지만, 아직 다양한 연구가 이루어지고 있지 않다. 본 연구에서는 원통형 막가습기의 열 및 물질 전달 특성을 이해하기 위한 특성 실험을 수행하였다. 기존의 습도 측정계는 비정상 가습 특성 실험에 한계가 있고, 정상 상태에서도 고온 다습한 환경에서는 오차가 크기 때문에 본 연구에서는 습증기 응축법을 이용하였다. 가습기의 정상상태 특성을 확인하기 위해 압력과 온도 변화에 대한 실험을 수행하였으며, 비정상 특성을 확인하기 위해 순간 유량 변화 시의 가습 성능을 측정하였다. 본 연구에서는 이상의 기초 실험을 통해서 막 가습기의 성능에 영향을 미치는 주요 인자를 확인하였으며, 원통형 막가습기의 기초적인 열 및 물질 전달 특성을 이해하였다. The proton exchange membrane (PEM) fuel cell system is critically dependent on the humidity, which should be properly maintained over the entire operating range. A membrane humidifier is used for the water management in the PEMFC because of the membrane humidifier’s reliable performance and zero parasitic power loss. In the PEMFC system, the membrane humidifier is required to provide appropriate humidity for the design point of the fuel cell. Although the performance of the fuel cell depends on the performance of the humidifier, few studies have provided a systematic analysis of the humidifier. We carry out an experimental analysis of the membrane humidifier using a vapor condensation bottle. The dry air pressure, water flow temperature, and air flow rate were chosen as the operating parameters. The results show that the time constant for the dynamic response of the membrane humidifier is relatively short, but additional analysis should be carried out.
양지훈,Kang Donggu,An SangHyun,Ryu Jeong Yeop,Lee KyoungHo,Kim Jun Sik,Song Moon-Yong,Kim Young-Sik,Kwon Sang-Mo,Jung Won-Kyo,Jeong Woonhyeok,Jeon Hojun 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00
Until recent, there are no ideal small diameter vascular grafts available on the market. Most of the commercialized vascular grafts are used for medium to large-sized blood vessels. As a solution, vascular tissue engineering has been introduced and shown promising outcomes. Despite these optimistic results, there are limitations to commercialization. This review will cover the need for extrusion-based 3D cell-printing technique capable of mimicking the natural structure of the blood vessel. First, we will highlight the physiological structure of the blood vessel as well as the requirements for an ideal vascular graft. Then, the essential factors of 3D cell-printing including bioink, and cell-printing system will be discussed. Afterwards, we will mention their applications in the fabrication of tissue engineered vascular grafts. Finally, conclusions and future perspectives will be discussed.