자연과의 대화학습

임정환 대구교육대학교 초등교육연구소 1988 초등교육연구논총 Vol.1 No.-

DEVELOPMENT OF A FLOW NETWORK SIMULATION PROGRAM PART I – FLOW ANALYSIS

임정환,황용서 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.6

An in-house simulation program was developed that can be utilized to predict flow characteristics such as pressure and velocities in any flow network system comprising multiple flow components, i.e., pipe, pump, heat exchanger, valves, etc. Although the code is intended for applications to network flow systems in a vehicle, it is written in a generalized manner to handle any possible network configuration of flow components. Therefore, it can easily function in various industrial applications. The network system where the flow is assumed to be one-dimensional is mathematically formulated by applying two conservation rules, mass and energy, to each flow component. These rules produce a set of non-linear equations. These non-linear equations are solved iteratively by adopting the Newton-Raphson scheme. This program has been tested in many different cases to demonstrate its validity and applicability. In this paper, two examples are introduced to show how the program can be used to find solutions in real engineering problems. Throughout the study, it was found that the code can most efficiently be used to verify a proposed design concept in an early design stage of the vehicle development cycle. The thermal analysis portion of the program will be dealt with in Part II of the paper. An in-house simulation program was developed that can be utilized to predict flow characteristics such as pressure and velocities in any flow network system comprising multiple flow components, i.e., pipe, pump, heat exchanger, valves, etc. Although the code is intended for applications to network flow systems in a vehicle, it is written in a generalized manner to handle any possible network configuration of flow components. Therefore, it can easily function in various industrial applications. The network system where the flow is assumed to be one-dimensional is mathematically formulated by applying two conservation rules, mass and energy, to each flow component. These rules produce a set of non-linear equations. These non-linear equations are solved iteratively by adopting the Newton-Raphson scheme. This program has been tested in many different cases to demonstrate its validity and applicability. In this paper, two examples are introduced to show how the program can be used to find solutions in real engineering problems. Throughout the study, it was found that the code can most efficiently be used to verify a proposed design concept in an early design stage of the vehicle development cycle. The thermal analysis portion of the program will be dealt with in Part II of the paper.

觀察指導 小考

林貞煥 大邱敎育大學校 科學敎育硏究所 1978 과학·수학교육연구 Vol.3 No.-

복합재를 적용한 반사판 안테나 곡면 패널의 반사 특성 측정을 위한 새로운 방법

임정환,이재욱,이택경,정화영,유제우,이재민 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.11

It is essential to analyze the electrical characteristics of composite materials, such as Carbon Fiber Reinforced Polymer(CFRP), as their electromagnetic properties change according to the method of fabrication. However, the conventional method cannot be applied to paraboloid-shaped deployable reflector antenna panel. In this paper, we analyze the effect of errors generated by waveguide to coaxial adapter while measuring the reflection characteristics of a curved specimen. Using the proposed structure of the adapter, it is confirmed that the reflection characteristics of a curved specimen can be measured by compensating the effect of error that occurs at the interface between the curved surface and the vertical flange waveguide.

경추 척수병증 환자에 있어서 Phase-Contrast Cine MRI 평가의 임상적 유용성

임정환,송준혁,신규만,김성학,Lim, Jeong-Hwan,Song, Jun-Hyeok,Shin, Kyu-Man,Kim, Sung-Hak 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.12

Objective : The cerebrospinal fluid(CSF) pulsates within the craniospinal axis in response to rhythmic cerebral blood volume variation during the cardiac cycle. The aim of this study is to characterize the normal and abnormal CSF flow and its waveforms in the cervical spinal subarachnoid space. Methods : The magnetic resonance(MR) images were obtained with 1.5 T(GE Signa, GE Medical Systems, Milwaukee, USA) unit using the 2 dimensional cine PC(phase contrast) sequence with cardiac gating and gradient recalled echo imaging. This pulse sequence yielded 16 quantitative flow-encoded images per cardiac cycle. Sagittal and axial images of the cervical spinal CSF space were obtained, and target sites were analyzed for characteristic CSF flow (TR=50ms, TE=12.5-15ms). The region of interest(ROI) was 1mm 3 in volume. Twenty six persons were included in this study : 10 healthy volunteers and 16 patients with cervical myelopathy. The post-operative cine MR study were also done in five patients. Results : The normal CSF pulsation dynamics in the cervical spine showed discrete systolic and diastolic components. The CSF flow revealed a sine wave pattern, in which the systolic phase was shorter than the diastolic phase(ratio=2 : 3). The patient group revealed decreased amplitudes of the CSF flow and irregularly distored flow waves. The systolic phase was elongated in the ROI above the stenotic level, whereas the diastolic phase was lengthened below the level. In the postoperative images, the abnormal pattern and amplitude were found to be corrected. Conclusion : From these results, the authors believe that the CSF flow study provides valuable informations regarding the extent of cervical stenosis and may be useful for the surgical planning and post-operative evaluation.

소금쟁이(Water-strider, Aquarius Paludum Fabricius)의 社會構造에 對하여

林貞煥 대구교육대학교 1967 論文集 Vol.3 No.-

1967年 7∼8月에 걸쳐 日本 岡山市 스포츠 센터內의 연못에서 소금쟁이의 테리터리 構造 및 그에 따른 社會行動에 對해서 調査 硏究하였다. 1) 소금쟁이의 各 個體는 水面上의 어떤 部分에 活動面을 가지고 거기에서 活動하는 傾向이 있다. 活動面의 占居者는 싸움에 依해 活動面을 侵入者로부터 지켜지는데 이 活動面을 테리터리라 할 수 있다. 2) 테리터리는 늘 Amoeba狀의 型으로 變하고 어떤 範圍內를 流動하는 動的인 것으로서 테리터리의 境界는 明確히 認定하기 困難하다. 그리고 테리터리는 周緣部에서 서로 重複되어 있다. 3) 소금쟁이의 테리터리 構造는 어떤 場所와 個體와의 心理的인 結合과 同時에 個體間의 社會力學的인 關係로서 維持된다고 생각된다. 4) 鬪爭은 4種類가 觀察되었다. 第1은 테리터리 防禦를 위한 싸움. 第2는 먹이를 얻기 위한 싸움. 第3은 ??를 빼앗기 위한 ??間의 싸움. 第5는 新入者에 對한 定住者의 攻擊이었다. The territorial organization and social behaviors of a water-strider, Aquarius paludum Fabricius were observed on a pond of OKAYAMA city sport center(OKAYAMA province, papan), during the mnths of August and September, 1967. 1. Each water-strider shows a strong tendency to occupy its domain on the water surface where the normal activity of individual water-striders take place. The portion of thecccupied domain is defended by the occupant through fighting against intruders. Therefore, itmay be said each individual has its own territory. 2. The territory of the water-strider is not concrete in pattern as it always changes its shape just as an amoeba does and slides about within a limited space. So the territorial boundary is obscure at any time. The territories of two or more individuals overlap one another especially at their marginal parts. 3. The territorial organization of the water-strider is held by the dynamic tension among the individuals as well as by the close attachment of each individual to a definite part of the water surface. 4. Four kinds of fighting have been observed: first, aggression by the occupant of a territory against intruders: second, warfare among the individuals to get foods falling on the water surface; third, fighting among the males to acquire a female or through unknown reasons: and last, the aggresion by the resident against the new commers into the artificial station. The fighting behaviors in the latter two cases are fiercer than those of the former ones.

광역관측 운용 모드에 대한 Quad-pol SAR 시스템의 성능 분석

임정환,윤성식,이재욱,이택경,유상범,이현철,이상규 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.2

In this study, we propose a performance analysis of a quadrature-polarimetric(quad-pol) synthetic aperture radar(SAR) system for wideswath operation mode and compare it with a single-pol system based on the operation mode. To achieve a shorter revisit time for an SAR satellite, we must observe a wide area, and two SAR operation modes exist for this purpose, which are called ScanSAR and SweepSAR. In general, a quad-pol SAR system can obtain a greater variety of information about a target than a single-pol system. Because this system affects system performance parameters, analyzing these effects is required. Based on a performance analysis of the wide-swath quad-pol SAR system, the system parameters and appropriate operation mode can be selected to satisfy the performance requirements.

상악동 악성 종양의 전산화단층촬용 소견

임정환 대한영상의학회 1991 대한영상의학회지 Vol.27 No.6

This report is a retrospective study of 20 histologically proven malignant maxillary sinus cancer patients treated in the Dept. of Tumor clinic, Presbyterian Medical Center from Apr. 1982 to Aug. 1990. CT in an excellent imaging modality to asses accurately the extent of malignant maxillary carcinoma. The results were as follows: 1. The average age of the patients was 52.3 years old. 2. Histologically, the cancers were composed of epidermoid carcinoma, rhabdomyosarcoma, osteosarcoma, adenoidcystic carcinoma, adenocarcinoma and undifferentiated carcinoma. 3. All cases are advanced in instage. 4. CT findings of mixillary sinus cancer were soft tissue density filling the maxillary antrum, soft tissue dunsity beyond the antrum, low density within the mass, punctate or amorphous calcifications within the mass, antral expansion and irregular bony wall thickeness, maxillary bony wall destruction, lymphadenopathy and distant metastasis. 5. Destruction of surfaces of maxillary bony walls were seen in the nasal surface(20 cases), facial surface(16 cases), intratemporal surface(14 cases) and orbital surface(11 cases). 6. The superioty of CT 개 the conventional sinus radiologic imaging were evident in different are as of tumor evaluation of tumor invasion to the infratemporal fossa, posterior ethmoid sinus, orbital apex, nasopharynx, cribriform plate, sphenoid sinus and skull base. 7. The limitations of CT in evaluation of maxillary sinus was evident in woys, poor differentiation between pooled secretion within the obstructed sinuses and tumor, and determination of invasion of soft tissue structures.

自然科 敎育의 學習評價에 對한 硏究 : 形成評價를 中心으로 Centered on the Formative Evaluation

林貞煥 대구교육대학교 1975 論文集 Vol.11 No.-

Compared with the existing view of evaluation, its new concept has been broadened and diversified. The present evaluation emphasizes its administrative and functional aspect while the new one places emphasis on its guiding and researching aspect. The desirable types of the evaluation of the elementary science education are summarized in three: Diagnostic, Formative and Summative evaluation. The thing to be stressed most in the evaluation of the elementary science education may be the procedure of the formative evaluation. It is as follows: 1. The learning objectives of the unit are subdivided into the actual behavioral objectives. 2. The unit to be studied is analyzed and selected. 3. The components included in the unit are analysed and an analysed evaluation chart is made. 4. Evaluation questionnaire is made and finally the evaluation begins.

소리.냄새상표의 효율적인 운영방안에 관한 연구

임정환,Im, Jeong-Hwan 한국특허정보원 2007 Patent 21 Vol.75 No.-