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비열플라즈마와 라디칼을 이용한 디젤엔진의 매연 및 NO 제거 특성
장영준,최승환,김규보,전충환,Jang, Yeong-Jun,Choe, Seung-Hwan,Kim, Gyu-Bo,Jeon, Chung-Hwan 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.4
We are facing the serious environmental pollution difficulties such as acid rain, green house effects, etc. The gaseous matter NOx, SOx, VOCs which are regarded as main factors for these current pollutions are mainly emitted from power plants and vehicles. Therefore several leading countries are regulating the emissions strictly, especially the exhaust emissions from a Diesel engine without an aftertreatment device. The objective of this study is to find out soot and NO removal characteristics focused on the emissions of a Diesel engine by using nonthermal plasma for each engine speeds and loads. Electrostatic precipitator(wire-to-plate type reactor) is used for soot removal. Radicals generated from outer air and put into a mixing chamber in the end of exhaust line are used for NO removal. Concentration of exhaust emissions is analyzed from the gas analyzer(KaneMay) and FTIR to estimate by-products.
코경유 눈물주머니코안연결술 전 통상적인 이비인후과 의뢰의 임상적 효용성
장영준,김호창,서억수,Young Jun Jang,Ho Chang Kim,Eok Soo Suh 대한안과학회 2012 대한안과학회지 Vol.53 No.10
Purpose: To determine if routine otorhinolaryngologic referral prior to endonasal dacryocystorhinostomy (EN-DCR) is necessary. Methods: Two hundred thirty-seven eyes of 178 patients who were supposed to undergo EN-DCR were prospectively analyzed. Nasal endoscopy was performed by an ophthalmologist and the patients who had severe abnormality were referred to an otorhinolaryngologist. The patients were classified into 3 groups after a preoperative examination by an ophthalmologist and an otorhinolaryngologist; the number and success rate of each group were then investigated. Group A consisted of patients who had no nasal cavity abnormality, Group B consisted of patients with a nasal cavity abnormality but who received no treatment, and Group C consisted of patients who had a nasal cavity abnormality and received otorhinolaryngologic treatment. Results: The number of subjects in each group was 156 in Group A (87.7%), 12 in Group B (6.7%), and 10 in Group C (5.6%). The number of patients who were referred to the otorhinolaryngologist was 22 (12.3%). There was no statistical significance of success rate between the groups. Conclusions: Routine nasal endoscopic examination should be performed by an ophthalmologist prior to EN-DCR. Only patients with severe abnormal findings should be referred to an otorhinolaryngologist as the results from the present study show the percentage of patients having significant nasal abnormalities was found to be low (12%) and the success rate of EN-DCR revealed no statistical significance between the groups. This could help patients by saving time and expense. J Korean Ophthalmol Soc 2012;53(10):1392-1396
장영준(Youngjun Jang),이민석(Minsuk Lee) 한국정보과학회 2012 한국정보과학회 학술발표논문집 Vol.39 No.1A
본 논문에서는 닌텐도 DS를 이용하여, 임베디드 소프트웨어 교육을 수행하기 위한 준비 과정과, 실제교육 내용을 소개하고, 향후 계획을 공유하고자 한다. 닌텐도 DS는 가격이 저렴한 게임기로 ARM9, ARM7 두 개의 CPU를 가지고 있으며, 기본적인 입출력 장치, 그래픽 가속기, 무선랜 등을 모두 포함하고 있다. 우리는 이 닌텐도 DS에 실시간 운영체제인 FreeRTOS를 이식하고, Eclipse 기반의 IDE 개발 도구 및 원격 디버깅 환경을 구축하였다. 또, 교육 과정에서는 하드웨어의 제어, RTOS의 기본 API의 활용, IPC, 동기화 문제의 해결에 이르는 주제를 포함함으로써 임베디드 소프트웨어 엔지니어가 지녀야할 기본적인 스킬들을 두루 다루는 실습이 되도록 구성하였다. 개발된 교육 환경 및 실습을 위한 강의 자료는 공개 소프트웨어로서 100% 공개되어 누구나 이용할 수 있다.
Si 도핑된 사면체 비정질 카본 코팅의 열 안정성 및 고온 내구성 특성
장영준(Young-Jun Jang),김원석(Won-seok Kim),장지웅(Ji-woong Jang),김종국(Jongkuk Kim) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
수소를 포함하는 비정질 카본 (hydrogenated amorphous carbon, a-C:H)의 경우, 사용 온도 500 ℃ 이하에서 수소 손실에 따른 열분해와 코팅 막에서 취성이 발생하여 고온 환경으로의 적용에 있어 작동 온도가 제한된다. 이를 위해, 수소를 포함하지 않은 사면체 비정질 카본 (tetrahedral amorphous carbon, ta-C) 코팅이 대체 재료로 각광받고 있으나 sp<sup>3</sup> 분율과 경도가 높아 적용하는 코팅 막의 내열성과 내마모 특성은 우수하지만 상대 재료의 마모가 증가되는 단점이 있다. 이러한 문제해결과 고온에서의 작동 온도 증대를 위해, nitrogen, boron, silicon, fluorine 등 전이금속 (transition metal)을 포함하는 DLC 코팅 막 합성이 수행되고 있다. 특히, Silicon 이 도핑 된 DLC 코팅은 다습 환경, 고온에서의 마찰 효과와 내구성 증가에 있어 중요한 관심사로 공정 개발이 이루어졌다. 그러나, 현재까지의 많은 연구는 Thetramethylsilane (TMS, Si(CH<SUB>3</SUB>)<SUB>4</SUB>), SiH<SUB>4</SUB> gas 등을 기저 물질로 PE-CVD 방법을 활용한 연구가 대다수이며 원천적으로 낮은 경도 (10 ~ 20 GPa) 범위로 제한적이다. 따라서, 본 연구에서는 수소를 포함하지 않은 ta-C 코팅 중 Si doping 이 ta-C 코팅의 미세 구조, 기계적, 다양한 온도 환경에서의 트라이볼로지 특성 영향에 대한 연구가 수행되었으며 그 결과를 소개하고자 한다. In the case of hydrogen-containing amorphous carbon (a-C:H), thermal decomposition due to hydrogen loss and brittleness occurs in the coating film at a use temperature of 500 °C or less, which limits the operating temperature in application to a high-temperature environment. A tetrahedral amorphous carbon (ta-C) coating that does not contain hydrogen is gaining popularity as an alternative material. However, due to the high sp<sup>3</sup> fraction and high hardness characteristics, the coating film has excellent heat resistance and abrasion resistance, but there is a disadvantage in that the wear of the counterpart material is increased. In order to solve this problem and increase the operating temperature at high temperatures, synthesis of a DLC coating film containing a transition metal such as nitrogen, boron, silicon, and fluorine has been performed. In particular, silicon-doped ta-C coating has been developed as an important concern in increasing the friction effect and durability in a high humidity environment and high temperature. However, many studies to date have mostly used the PE-CVD method using Thetramethylsilane (TMS, Si(CH<SUB>3</SUB>)<sub>4</sub>), SiH<SUB>4</SUB> gas, etc. as base materials, and are limited to the low hardness (10 ~ 20 GPa) range. Therefore, in this study, a study on the influence of the microstructure, mechanical, and tribology characteristics of the ta-C coating on the high temperature environments.
고속 컨테이너선 운항의 경제성 분석에 관한 연구 -동북아시아 근해 해상운송 서비스를 중심으로-
장영준 ( Yeang Jun Jang ),류동근 ( Dong Keun Ryoo ) 한국해운물류학회 2004 해운물류연구 Vol.41 No.-
The objective of this research is to examine the economic viability of operating a fast containership in short sea services in North-East Asia in comparison with 700TEU and 340TEU containerships. The results of the research present that at the average market freight rates of $438 per TEU, the fast containership is not economical and has a loss of $92 per TEU. The results of the sensitivity analysis in terms of freight levels indicate that the fast ship will gain $20 per TEU as earnings of before interest and tax at the freight rate of $550 per TEU and its break-even TEU is 490TEU per voyage. The results of the sensitivity analysis in terms of fuel costs show that when daily fuel costs of the fast containership is sevenfold comparing to that of the 340TEU ship, the fast ship will earn a net profit of $8,537 annually and its break-even container number is 511TEU.