H₂/Air 비예혼합화염의 화염신장율에 따른 NO 생성경로의 상세해석

김종현,황철홍,이창언,Kim, Jong-Hyun,Hwang, Cheol-Hong,Lee, Chang-Eon 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.8

Detailed analysis of NO formation routes and its contributions with strain rate in hydrogen/air flames were numerically investigated. LiG detailed reaction mechanism has been used for calculation, which is compared with experimental data in literature. It shows good agreement with experiment for both temperature and NO mole fraction. Three routes have been found important for NO formation in hydrogen flames. These are the Thermal route, NNH route and $N_2O$ route. Strain rate were varied to discuss the $EI_{NO}$ reduction trend in hydrogen nonpremixed flames, which are analyzed by each NO formation routes. As a result, as the strain rate increase, $EI_{NO}$ decrease sharply until strain rate $100s^{-1}$ and decrease slowly until strain rate $310s^{-1}$ again, after that $EI_{NO}$ keeps nearly constant. It can be identified that $EI_{NO}$ trend with the strain rate is well explained by a combination of variation of production rate of above Thermal, NNH and $N_2O$ route. Also result of Thermal-Mech. that includes only thermal NO reaction is compared with those of Full-Mech. As a result, It can be identified that there was difference between the two results of calculation. It is attributed to result that Thermal-mech did not consider contributions of NNH and $N_2O$ route. From these result, we can conclude that NOx emission characteristics of hydrogen nonpremixed flames should consider contributions of above three routes simultaneously.

주조시 비정상 유동에 대한 수치해석

김종현,임인철,김성식 ( Jong Hyun Kim,In Cheol Lim,Sung Sik Kim ) 한국주조공학회 1992 한국주조공학회지 Vol.12 No.1

주조시 주형내의 유동해석을 위해서는 시간에 따라 변화하는 자유표면 위치에 대한 정확한 정보가 요구되는 관계로 난제로 여겨져 왔다. 따라서 대부분의 연구는 초기치 속도를 정의하기 위해서 순간충입(instantaneous filling)을 가정하여 수치 해석을 하였던 것이다. 본 연구는 Modified Solution Algorithm-Volume of Fluid Method (MSOLA-VOF)를 개발하는 주조시 주형내의 유동을 수치적으로 해석하며, 유속이 수평 주조, 수직 주조의 경우에 어떤 영향을 미치는가에 대하여 연구하였다. 결론으로 응고 연구에 있어서 초기의 순간충입은 비현실적인 가정이라는 것이 밝혀졌으며, 충입시 초기 속도 분포와 결정 생성은 밀접한 관계가 있음을 알 수 있었다. N/A

직무분석에 의한 화학공학 교과과정 개발 - 동서대학교 사례연구 -

김종현,Kim Jong-Hyun 한국공학교육학회 2000 공학교육연구 Vol.3 No.2

Possible directions of chemical engineering education have been proposed in many studies. However, new curriculum is demanded to accommodate the special needs of our students' level and community industrial characteristics. We can think of two reasons. One is that various kinds of chemical engineering industry are found in every community. The other is that students' educational standards are different in every university. We have surveyed and analyzed jobs of our university graduates who are working in chemical company of our community Pusan and Kyoung-Nam. This study aims to develop the new curriculum with an emphasis on practical education and to propose the new direction for our major characteristic based on the survey. 여러 보고서를 통하여 미래의 화학공학 교육의 방향이 제시되어 있지만 각 지역마다 분포되어 있는 화학산업의 종류가 다르고 대학별로 지원하는 학생들의 학습능력이 다르므로 학습자의 능력과 지역산업에 부합하는 교과과정이 요구된다. 따라서 본 연구에서는 부산, 경남 지역의 화학회사에 취업하고 있는 졸업생을 대상으로 직무분석을 하여 실무중심의 교과과정을 개발하고 전공의 특성화를 위한 방향을 제시하고자 한다.

수열합성법을 이용하여 우선 배향된 ZnO 나노와이어 성장 및 발광 특성

김종현,임연수,김성현,조진우,정대용,Kim, Jong-Hyun,Lim, Yun-Soo,Kim, Sung-Hyun,Jo, Jin-Woo,Jeong, Dae-Yong 한국재료학회 2011 한국재료학회지 Vol.21 No.12

1-D ZnO nanowires have been attractive for their peculiar properties and easy growth at relatively low temperature. The length, diameter, and density of ZnO nanowires were determined by the several synthetic parameters, such as PEI concentration, growth time, temperature, and zinc salt concentration. The ZnO nanowires were grown on the <001> oriented seed layer using the hydrothermal process with zinc nitrate and HMTA (hexamethylenetetramine) and their structure and optical properties were characterized. The morphology, length and diameter of the nanowires were strongly affected by the relative and/or absolute concentration of $Zn^{2+}$ and $OH^{-1}$ and the hydrothermal temperature. When the concentrations of the zinc nitrate HMTA were the same as 0.015 M, the length and diameter of the nanowires were $1.97{\mu}m$ and $0.07{\mu}m$, respectively, and the aspect ratio was 28.1 with the preferred orientation along the <001> direction. XRD and TEM results showed a high crystallinity of the ZnO nanowires. Optical measurement revealed that ZnO nanowires emitted intensive stimulated UV at 376 nm without showing visible emission related to oxygen defects.

탄소나노튜브/아교 접착제를 이용한 돌침대용 목재 샌드위치 복합재의 계면, 열적 및 방수특성 증가

김종현,권동준,신평수,백영민,박하승,문선옥,박종만,Kim, Jong-Hyun,Kwon, Dong-Jun,Shin, Pyeong-Su,Baek, Yeong-Min,Park, Ha-Seung,Moon, Sun-Ok,Park, Joung-Man 한국복합재료학회 2017 Composites research Vol.30 No.4

Animal glue, a water-soluble adhesive, has been used historically for high-performance traditional furniture despite the disadvantage of weakness against moisture. Many scientists studied the ways to improve water resistance of animal glue. Improvements on the interfacial, thermal, and water resistance properties of wood sandwich composites (WSC) was studied with carbon nanotube (CNT) wt% in animal glue. Real-time temperature of WSC was measured after WSC was heated with increasing CNT wt%. Lap shear test was performed to determine the interfacial properties of wood and animal glue with CNTs. Water resistance properties of animal glue were determined by lap shear test using specimens dipped in water and the results were compared with the dry case. Hydrophobicity of animal glue by static contact angle was correlated with the variation of lap shear test. Interfacial, thermal, and water resistance properties for animal glue were improved with properly added CNTs. 아교는 수용성을 띄는 접착제로, 이 특징에 의해 물에 약하다는 단점에도 불구하고 전통적인 고가구에 많이 사용되어 왔다. 이러한 단점을 개선하기 위하여 많은 연구가 진행되고 있다. 본 연구에서는 탄소나노튜브를 도입에 따른 아교의 계면특성 및 열적특성 그리고 방수특성 개선에 대한 연구를 진행하였다. 탄소나노튜브의 비율이 증가함에 따라 아교를 이용하여 접착한 돌침대용 목재 샌드위치 판 상부의 실시간 온도측정을 진행하였다. 나무와 아교접착제 간의 계면특성의 변화를 알아보기 위하여 랩 전단 실험을 실시하였고, 습도가 높아짐에 따라 물성이 약해지는 아교의 단점을 개선하기 위하여 탄소나노튜브를 도입에 따른 아교의 방수특성이 개선되는지 대한 실험을 진행하였다. 랩 전단시편을 물에 담근 후 랩 전단 실험을 진행하여 기존의 결과와 비교하여 차이가 얼마나 나는지 비교하였다. 이를 증명하기 위하여 물과의 정적 접촉각을 이용해 탄소나노튜브의 함량에 따른 아교접착제의 소수성 정도를 비교하였다. 실험결과 아교 접착제에 탄소나노튜브를 도입으로 계면특성, 열적특성 및 방수특성이 개선되었다.

CAN기반 시스템의 통신 신뢰성 검증

김종현,정기현,최경희,Kim, Jong-Hyun,Chung, Ki-Hyun,Choi, Kyung-Hee 한국정보처리학회 2008 정보처리학회논문지 C : 정보통신,정보보안 Vol.15 No.3

CAN은 처음에는 차량 네트워크에서의 사용을 위해 고안되었으나 잡음에 강하고 신뢰성이 높아 공장자동화 등에서도 많이 사용되고 있다. 그러나 1:1통신에서 네트워크 기반의 통신방식으로 변화되면서 각 장치의 기계적인 동작뿐만 아니라 전자, 소프트웨어적인 동작에 대해서도 철저한 검증이 필요하게 되었다. 본 논문은 CAN 기반 시스템에서 통신의 신뢰성을 데이터의 정확성에 대한 부분과 시간상의 정확성에 대한 부분을 검증하는 방법을 제시하고 있다. Controller Area Network was developed originally for in-vehicle communication network. But it is now widely used for factory automation because of its properties such as strong noise resistance and high reliabilities. With changing communication environments from peer to peer topology to bus topology, we should check each devices about not only mechanical operations but also electronic or software operations. In this paper, we suggest reliability test environment for CAN based system, which is divided two parts, data correctness and timely delivery.

청신경 초종 수술에서 골미로를 통한 접근법의 유용성

김종현,조태구,박관,박익성,남도현,이정일,조양선,홍성화,홍승철,신형진,어환,Kim, Jong Hyun,Cho, Tae Goo,Park, Kwan,Park, Ik Seong,Nam, Do-Hyun,Lee, Jung-Il,Cho, Yang-Sun,Hong, Sung Hwa,Hong, Seung-Chyul,Shin, Hyung-Jin,Eoh, Whan 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.6

Objective : To determine the feasibility of translabyrinthine approach in the vestibular schwannoma patients, the authors reviewed eighteen consecutive cases, focusing at their functional outcome and operative complications. Materials and Method : To evaluate the functional outcome, we reviewed preoperative radiological findings such as size of tumors and location of jugular bulb as well as the preoperative neurological status including audiometric analysis and cranial nerve function in 18 patients, diagnosed as vestibular schwannoma. Also the surgical outcome was evaluated according to the functional preservation of facial nerve and incidence of the surgical complication as well as the extent of surgical resection. Results : The age of patients ranged from 21 to 62 years, with a mean of 50 years. Of 18 patients operated in our center by the translabyrinthine approach, wide exposure with total removal of the mass was possible in 16 cases (88.8%). The facial nerve was anatomically preserved in 88.8%. At six-month follow-up, facial nerve function was good(Grade I-II) in 15 patients(83%) and acceptable(I-IV) in all patients. Although the jugular bulb was highly placed is five patients, gross total resection was possible without facial nerve injury in all patients by the translabyrinthine approach. One patient experienced CSF leakage after surgery, but there was no patient with disabling deficit. Conclusion : Use of the translabyrinthine approach for removal of vestibular schwannomas resulted in good anatomical and functional preservation of the facial nerve, with minimal incidence of morbidity and no mortality. In cases of high jugular bulb impacted into mastoid bone, total removal was possible by displacing the jugular bulb with Surgicel cellulose and placement of bone wax.

Unilateral Hydrocephalus in Congenital Atresia of the Foramen of Monro

김종현,정용구,이남준,김세훈,이훈갑,이기찬,서중근,Kim, Jong Hyun,Chung, Yong Gu,Lee, Nam Joon,Kim, Se Hoon,Lee, Hoon Kap,Lee, Ki Chan,Suh, Jung Keun The Korean Neurosurgical Society 2000 Journal of Korean neurosurgical society Vol.29 No.3

일측성 수두증은 여러가지 원인에 의해 발생될 수 있으나 주로 종양이나 감염등에 의한 후천적인 몬로공 폐쇄의 경우가 대부분이고 선천성 몬로공 폐쇄에 의한 일측성 수두증은 그 예가 많지 않다. 산전초음파 검사로 태아의 선천성 일측성 수두증을 진단했고 출산 후 수술적 방법을 통해 치료한 예는 국내에 아직 보고된 바가 없어 이를 문헌고찰과 함께 보고한다. Unilateral hydrocephalus is an uncommon disease which may result from obstruction of the foramen of Monro. Congenital or acquired lesions obstructing this foramen have been reported. We present a case of prenatally diagnosed fetal unilateral hydrocephalus. Ventriculoperitoneal shunt operation was performed and following the procedure, ventricular size was decreased and patients neurological status was improved.

최근 4년간 명절기간과 평상시 교통사고 비교연구

김종현,유진화,Kim, Jong-Hyun,Yoo, Jin-Hwa 대한교통학회 2011 교통 기술과 정책 Vol.8 No.5

인터리브드 멀티홉 인증을 적용한 무선 센서네트워크에서 퍼지로직을 이용한 서비스 거부 공격에 대한 방어 기법

김종현,조대호,Kim, Jong-Hyun,Cho, Tac-Ho 한국시뮬레이션학회 2009 한국시뮬레이션학회 논문지 Vol.18 No.3

When sensor networks are deployed in open environments, an adversary may compromise some sensor nodes and use them to inject false sensing reports. False report attack can lead to not only false alarms but also the depletion of limited energy resources in battery powered networks. The Interleaved hop-by-hop authentication (IHA) scheme detects such false reports through interleaved authentication. In IHA, when a report is forwarded to the base station, all nodes on the path must spend energies on receiving, authenticating, and transmitting it. An dversary can spend energies in nodes by using the methods as a relaying attack which uses macro. The Adversary aim to drain the finite amount of energies in sensor nodes without sending false reports to BS, the result paralyzing sensor network. In this paper, we propose a countermeasure using fuzzy logic from the Denial of Service(DoS) attack and show an efficiency of energy through the simulataion result.