中學生의 學習樣式과 TA 自我狀態가 數學的 問題解決力에 미치는 影響

박재환 한국교원대학교 1997 국내석사

Si(111) 표면에 형성된 인듐 원자층의 구조와 전기적 특성에 관한 제일원리연구 : First-Principles Study of the Structural and Electronic Properties of the Indium Overlayers on the Si(111) surface

박재환 포항공과대학교 일반대학원 2015 국내박사

We have studied the Au-intercalated graphene/Ni(111) surface and the In adsorbed Si(111)-(root7×root3) surface as the representative examples of 2D layered structures on substrates by using density-functional theory calculations. Varykhalov et al. reported that graphene grown on the Ni111) surface and intercalated by 1 monolayer Au displays an electronic band structure very close to that of perfect 2D free-standing graphene by ARPES and STM study [Phys. Rev. Lett 101, 157601 (2008)]. However, this is not yet solid because it is based only on the filled state electronic-structure information. Consequently, the K doping was used to explore the Dirac-cone shape of the raphene/Au/Ni(111) surface and, interestingly, they reported that K doped graphene/Au/Ni(111) surface has a large band gap of 0.6 eV [Phys. Rev. B 82, 121101(R) (2010)], but existence and origin of the band gap is still debated. For the metal on semiconductor surface, In/Si(111)-(root7×root3) surface has been used to explore the ultimate 2D limits of In overlayer properties. Two different phases, distinguished by STM images, exist for the In adsorbed Si(111)-(root7×root3) surface, one is a quasi-rectangular and the other is a quasi-hexagonal image. In coverages of 1.0 ML and 1.2 ML have been experimentally proposed for hexagonal and rectangular phase, respectively. Because the (root7×root3) surface is known to be a one-atomic-thick structure, many experimental studies reported fascinating two-dimensional properties such as 2D free electron, superconductivity and metallic transport. Although many studies have been done to understand its atomic and electronic structure, a clear picture is not yet established. In this thesis, we first have studied the effect of Au intercalation on the atomic and electronic structure of the graphene/Ni(111) surface. Our calculations confirm a recent experimental claim that graphene grown on Ni(111) and intercalated by one monolayer Au can be regarded as quasifreestanding. We also verify the role of the K adsorbates on graphene/Au/Ni(111) as a simple donor, however, graphene pi character undergoes some weakening due to the hybridization with Ni d bands. For the In/Si(111)-(root7×root3) surface, our calculations show that both rectangular and hexagonal phases consist of an In double layer, contrary to the prevailing idea that the In overlayer on this surface is just one atom thick. In addition, we discuss that origin bands of 2D free electron with the Fermi contour analysis which plays an important role in understanding the ARPES data. The present double-layer models for the In/Si(111)-(root7×root3) surfaces urge a reconsideration on the recent experimental claims that the In overlayer properties were pushed to a single-layer limit in this surface.

Alloderm의 骨幹 代替物質로서의 可能性에 關한 硏究

박재환 경상대학교 2003 국내석사

Python script를 이용한 지능형 토크컨버터 유동해석 제어 프로그램 개발

박재환 慶北大學校 2005 국내석사

The present article described development of a simulation managing program for continuous computational fluid dynamics (CFD) analyses in design application with torque converter for CVT. Designing a new torque converter used to require labor-intensive and time-consuming processes such as the CFD analysis that cannot be omitted. In the CFD analysis, there requires a series procedures including grid generation, applying boundary conditions, solving, and post-processing, which is used to be repeated by a CFD expertise at a time. These labor-intensive and time-consuming processes have been a major drawback of reduction in the development time. Thus, we developed a simulation managing program adopting a Python scripting function that is currently available in CFD-ACE. The simulation managing program is able to control the CFD analysis and provide the repeated processes such as grid generation, applying boundary condition, etc even though the geometry is modified. In the present research, the simulation managing program was successfully applied to the design of a thin torque converter for CVT. Since the present program with Python scripting is a simple GUI-based program, one can easily learn and use it. The advantage of the present simulation managing program is to reduce the time in pre-processing of CFD analysis after revising geometry. For example, one can restart a new computational flow analysis after modifying geometry within 5 min, which used to take at least 5 hrs.

신도시 청소년 수련관의 외부공간계획에 관한 연구

박재환 서울시립대학교 2004 국내석사

加壓 乳上法에 의한 乳濁 Oil의 除去에 관한 硏究

박재환 全北大學校 1982 국내석사

Waste water contatning Oil is difficult to treat with a conventional types of waste water tretment. Dissolved - Air Flotation(DAF) has proven to be a beneficial method of treating emulsified oil. The purpose of this paper is to review the theory of DAF and to expriment with DAF in order to achieve an efficient treatment for emulsified oil. The important factors associated with DAF are coagulant type and coagulant dose, pressure, ratio of pressurized liquid volume to sample volume, retention ti Ph, temperature and emulsified oil in feed. Especially, investigations in this expreiment by DAF were as followed : relationship between residual kerosene concentration and coagulant dose : relationship between residual kerosene concentration and ratio of pressurized liquid volume to sample volume. Also, emulsified kerosene as experimental meterial was chosen. Kerosene has boiling point of 150℃ to 180℃ and specific gravity of 0.790 to 0.830. Ferric Chloride as coagulant within the range of 10mg/1 to 50mg/1 was added to each sample. Presure varied within the range of 2㎏/㎠ to 5㎏/㎠ was applied to pressurized liquid. Ratio of pressurized liquid volume to sample volume varied within the range of 2.5% to 17.5% was applied to sample. And emulsified kerosene concentrations within the range of 10mg/1 to 35mg/1 were applied to the flotation vessel. Thus, the results obsained are as follows : 1. In spite of emulsified kerosene concentrations as varied within the range of 10.6 mg/1 to 24.4mg/1 and 33.2 mg/1 respectively, each of minimum value of residual kerosene concentrations was at a constant point of Ferric Chloride dose. Therefore, optimum amount of Ferric Chloride as a coagulant was 20 mg/1. 2. When emulsified kerosene concentration of 33.2 mg/1 was applied, minimum value of residual concentration was at a point of 4.0 ㎏/㎠ of pressure. And even if pressure increased in more than 4.0㎏/㎠ residual concentration treated was almost constant. 3. When ratio of pressurized liquid volume to sample volume was varied within the range of 2.5% to 17.5%, minimm valno of residual koresene concentration treated was at a point if 10% with v/vo ratio, and although v/vo ratio increased in more than 10%, residual concentration treated was almost constant.

民願行政의 實態와 發展方向에 關한 硏究

박재환 전남대학교 행정대학원 2002 국내석사

民願行政은 住民이 行政機關과 接觸하였을 때 비로소 民願關係가 成立한다. 따라서 行政의 一般的인 目標가 社會安定과 秩序維持, 國民統合, 社會變動促進·誘導 등인데 비하여 民願行政의 目標와 對象은 國民 개개인 또는 특정소수인의 직접적인 요구에 대한 奉仕라는 점이다. 또한 民願行政은 目標設定에서 評價, 是正措置 등에 이르는 행정과정 중에서 집행의 과정을 갖는 것으로서 민원인의 이해관계에 직접적인 영향을 미치며 처리결과에 대한 평가는 일반국민의 통합뿐만 아니라 한 국가의 政治權力의 效率性에도 영향을 미친다. 따라서 오늘날의 民願行政은 行政過程에 있어서의 民主性과 住民에 대한 對應性 確保 그리고 衡平性의 保障을 要求하고 있다. 특히 本格的인 地方自治制의 實施와 급격한 社會變動으로 인하여 地方住民들의 定策決定過程에의 참여욕구와 새로운 행정서비스에 대한 요구가 증대되고 있고, 政治的으로도 對民關係의 重要性이 강조됨으로서 민원행정의 발전방향이 절실히 요구되고 있는 실정이다. 이에 따라 본 硏究內容은 총 5장으로 構成되었으며, 제1장 序論에 이어 제2장에서는 民願行政에 관한 理論的 考察로써 민원행정의 개념과 유형 그리고 민원 행정절차에 있어서의 절차적 공정성의 구성요소 및 民願處理制度의 類型 등에 대하여 살펴보았고 제3장에서는 民願行政의 實態와 問題點을 分析해보고자 民願處理機關 및 關係法令에 대한 검토와 민원사무의 종류, 전라남도 민원사무처리 실태와 문제점을 도출하였으며, 특히, 1999년 12월부터 2000년 1월에 이루어진 全羅南道 顧客滿足度 調査에 대한 滿足度 및 改善點을 심층분석 하였으며, 민원처리에 있어 제도상, 운영상, 행태상의 문제점을 적시해 보았다. 제4장에서는 제3장에서 지적된 문제점에 대한 改善策 및 發展方向을 제시하였으며, 이를 위해서는 行政管理의 革新 및 參與와 公正性의 文化가 민원행정에 적극 도입되어야 함을 强調하면서 마지막으로 結論을 요약하였다. 現在의 行政環境에서 民願行政의 發展은 첫째, 기존의 민원관련 법제와 規定 및 組織과 節次가 公務員과 民願人들에게 價値와 安定을 가질 수 있도록 制度化 되어야겠다. 이에 따라 기존의 民願關聯 法制와 規定들이 民願人에게 거부감 없이 받아들여 질 수 있도록 弘報와 敎育 그리고 현실에 맞지 않는 組織과 節次의 整備가 있어야겠다. 아울러 공무원과 民願人의 節次에 대한 理解와 서로를 보는 관점의 轉換이 있어야 한다. 이를 위하여 旣存의 組織과 節次에 대한 合理的인 改善이 있어야 하겠다. 둘째, 民願行政이란 住民이 원하는 서비스를 提供하고 여기서 만족을 얻는 데 그 존재 意義가 있는 만큼 행정서비스를 주민의 입장에서 주민이 원하는 양질의 서비스를 迅速하게 提供하여야 하겠다. 즉 行政에 있어서의 規定과 規則은 適格性을 결정하는데 있어서 단지 안내의 척도를 제공하는 기능을 하기에 규정과 규칙의 해석은 주민의 이익과 합치되도록 하여야겠다. 이를 위해 複雜한 行政節次는 簡素化되어야 하고 行政處理의 모든 過程과 節次가 公開되어야 하겠다. 또한 이렇게 공개된 節次와 規定들은 一般原則에 따라 지켜지는 것도 중요하다. 셋째, 節次에 대한 認識의 轉換이 필요하다. 절차를 준수하면 시간과 비용이 많이 들고 결과가 좋으면 다 좋은 것이라는 그릇된 가치관에서 벗어나야 한다는 것이다. 이를 위하여 短期的인 成果에 집착하지 말아야 하고 長期的 안목에서 판단을 해야한다. 즉 장기적인 社會的 能率의 관점에서 節次의 준수가 時間과 費用을 절감할 수 있다는 것을 認識해야 한다. 이상과 같은 방향으로 나아갈 때 民願行政은 물론 民願人은 한층 더 발전된 행정서비스를 받게 되리라 믿어 의심치 않는다. In civil affairs adminstration, when residents contact with administrative organs, civil affairs relations may be formed. Thus, while the general purpose of administration is social stabilization, maintenance of social order, national unification, and promotion and incitement of social change, the purpose and target of civil affairs administration are the services for the demand of individual or specified persons. Besides, civil affairs administration has execution procedure in the course of administration, including evaluation and administrative indicator in establishing its purpose and directly affects the interests of the person concerned. The evaluation of managing result has an influence on state's effectiveness of political power as well as people's unification. Therefore civil affairs administration of today requires democratic administrative procedure, to secure counterplan to residents, and to ensure equity. Accordingly, this study consists of five chapters: Chapter 1 is introduction and Chapter 2 is theoretical consideration of civil affairs administration and examined the concept and type of civil affairs administration, component of procedural equity In administrative procedure, and type of civil affairs system. Chapter 3 considered civil affairs organizations and relevant regulations, deriving the situation of managing civil affairs administration and its problems in Jeollanam-do Province in order to analyze the state and problem of civil affairs administration. In particular, satisfaction and problem obtained from the Survey of Jeollanam-do Province Customer's Satisfaction, conducted from Dec. 1999 to Jan. 2000 was carefully analyzed, facing up to institutional, operational, and morphological problems. Chapter 4 suggested measures and development direction to improve the problem indicated in Chapter 3 and finally came a the conclusion, emphasizing that the innovation of administration and the culture of participation and equity should be aggressively introduced. To develop civil affairs administration in present administrative environment, first, existing regulations relevant to civil affairs and administration, organization, and procedure should be institutionalized to give stabilization to public servants and customers. Thus, publicity and education should be performed and the organization and procedure which conflict with the reality should be readjusted in order that customer can willing to accept the existing regulations and administration relevant to civil affairs. Also, public servant and customer should understand procedure and the view toward each other should be converted. Thus reasonable improvement of existing organizations and procedures should be followed. Second, considering that civil affairs administration has meaning to provide the service residents want and to satisfy them, the quality service residents want should be promptly provided in the side of residents. In other words, because regulations and rules in administration function as providing an only measure to guide in determining competence, their interpretation should be accordant to residents' interests. For this, complex administrative procedure should be simplified and all process and procedures of managing administration should be opened. It is also important to observe such an open procedure and administration according to the general principle. Third, it is needed to change recognition of procedure. We should escape from wrong values that obeying procedure costs us lots of money and time. We should not attach short-term process, but judge in the long view. We should recognize that if we observe procedure in social efficiency of the long view, time and cost will be reduce. When progressing toward the above direction, customer as well as civil affairs administration will provide much better administrative service.

可變 負荷用 高周波 電源 供給器의 製作

박재환 檀國大學校 1992 국내석사

기체 레이저와 같은 가변 부하는 방전 전후의 임피던스가 급격하게 변화한다. 이 현상으로 인한 임피던스 정합의 불편함을 해결하기 위하여 25∼40 ㎒의 주파수로 발진하는데 최대 출력 전력이 약 200 Watts인 RF 발진기를 제작하였다. 직류 전원으로부터 RF 전력으로의 변환 효율은 약 40∼80% 이다. 가상의 부하에 대한 실험 결과로부터 발진기의 발진 주파수는 부하 임피던스의 변화에 따라 자동적으로 변화하는 사실을 알았으며 실제의 가스방전 시스템을 부하로 한 경우에도 동일한 결과를 확인하였다. 결과적으로 제작된 고주파 고출력 발진기는 가변 부하용 전원 공급기로서 이용할 수 있다. In the RF gas discharge system, the load varies frequently by operating environments and conditions. And it is often necessary to change the matching netwrok to procide the maximum possible power transfer from the oscillator to the RF load. An RF oscillator whose variable operating frequency is between 25 and 40 ㎒ and whose maximum output RF power is about 200 watts was designed to solve these problems. The conversion efficiency from the DC power to the RF power was about 40∼80 %. It was found that the output oscillating frequency automatically follows the changes of the load or of the operating conditions. Also, it was verified from the experimental results of the dummy variable loads and the actual gas discharge system such as CO₂laser medium load that the constructed RF power oscillator can be used as RF power supply for the time varying loads.

First-principles Theoretical Study of In Adsorbed AuSi(111) Surface. : In 원자가 흡착한 Au/Si(111) 표면의 제일원리 이론연구

박재환 포항공과대학교 2009 국내석사

4족보행 로봇의 가변 임피던스 제어

박재환 한양대학교 대학원 2012 국내석사

The research in this thesis aims to realize stable trot of aquadruped robot on irregular terrain. Trotting on irregular terrain is difficult as undesirable impulse force by collision between the foot and an obstacle makes the robot unstable. To cope with the problem, it is necessary to adjust the interaction characteristic of the robot feet and the ground when terrain condition and locomotion phase are changed. The interaction characteristic can be modeled as an impedance model, which includes mass, spring, and damper. In this paper, variable impedance con-trol algorithm changing leg impedance parameters according to the change of finite states of quadruped trot is proposed. The state of quadruped trot is divided into five phases and the impedance parameters are changed to generate adequate response to the contact force in each contact phase. Simulation of trotting on irregular terrain with half-ellipsoidal trajectory has been performed with the control groups, which are the simulations without impedance control and with fixed impedance control. The simulations have verified that proposed control method shows outstanding per-formance and better stability for trotting on the highly irregular terrain. This thesis also contains hardware development of HUNTER, which is aquadruped robot based on the biological analogous of areal dog. HUNTER was built up with network-based sensors and actuators and asoftware guaranteeing real time process of control thread was built. With asimple experiment on trot, the feasibility of network-based actuators and control software for HUNTER has been verified.