(A) Study on Sea Water Freezing Behavior in a Flow Field with Bubbly Flow

One of the most essential things to maintain our lives is water. Water consumption is rapidly increasing due to the exclusive overpopulation, industrial development and improvement of people's living standards. However, only 1% of water source is available for human being, so the ever-increasing scarcity of water is getting serious as time goes by. Korea also will be no exception of this tendency and many researches have often proven how urgent Korea is water deficiency problem. In order to reduce this problem, we try to make the most water through building multi-functional dams, rainmaking and developing desalination system. Among those, desalination system is expected to be the most effective method because of its availability of seawater. It'll enable us to get water steady and readily. When we select particular kind of desalination system devices, that decision is mostly influenced by fresh water produce cost. In order words, its efficiency depends on whether we can achieve possible energy source easily or not. As environmentally friendly means, many people are encouraged to use LNG (Liquefied Natural Gas) in Korea and many countries of the world. Amount of LNG consumption is currently heading higher. In general, LNG which is stored below -162℃ in super-liquid tank requires certain energy to gasify because it changed into the gaseous state with high pressure wasted cold energy when it is sent to each part in need. LNG loses lots of cold energy (850kJ/kg) during this process of absorbing heat. To take advantage of this wasted cold energy, we are developing the systems such as producing the frozen food processing, dry ice, liquefied hydrogen, liquefied nitrogen and seawater freezing desalination. Therefore we'll mainly focus on the development of a seawater freezing desalination system and design technique using wasted cold energy necessary to freezing behavior of seawater. This study is intended to achieve qualitative and quantitative fundamental data with respect to it. The device mainly consists of test section(transparent acryl rectangular duct), a brine loopvisualizing the flow in freezing part, etc. After considering mean concentration of seawater measuring water and refined salt with digital balance and salinity meter, the operating fluid can function as 3.5wt% NaCl aqueous solution. We operate brine loop using ethylene glycol 40% aqueous solution within the temperature of -21.12℃(eutectic point of seawater). Visualizing section using nylon12 tracer measures PIV with Argon-ion laser. After injecting -0.5℃ air into the test-section accompanied by flow field, investigated the flow appearance in around cooled parts by using the PIV system. The experiments were carried out for a variety of parameter, such as sea water velocity, air-bubble flow rate, and cooled part temperature. The shape of freezing layer, freezing rate and salinity of frozen layer were observed and measured. And the flow patterns around cooled parts were visualized using the PIV to analyze the relationship between the flow structure and the freezing characteristics. It was found that the experimental parameters gave a great influence on the freezing rate and the salinity of the frozen layermaintaining the temperature of cooled parts, PIV(Particle Image Velocimetry) systemAbstract = ⅲ 사용기호 = ⅵ 제 1 장 서론 = 1 1.1 연구의 배경 = 1 1.2 종래의 연구 = 11 제 2 장 실험방법 및 실험범위 = 15 2.1 실험방법 및 실험범위 = 15 2.2 PIV = 20 2.3 해수의 동결거동 = 22 제 3 장 냉각원관에서의 해수동결 = 24 3.1 실험장치 = 24 3.2 냉각원관의 열전달해석 = 28 3.3 냉각원관 주위의 해수동결거동 = 33 3.4 유속의 영향 = 38 3.5 공기 분사량의 영향 = 48 3.6 냉각면 온도의 영향 = 58 3.7 동결량의 무차원정리 = 68 3.8 결론 = 70 제 4 장 수？邰嗔？ 냉각평판에서의 해수동결 = 71 4.1 실험장치 = 71 4.2 수직평행 냉각평판의 열전달해석 = 75 4.3 수직평행 냉각평판 주위의 해수동결거동 = 79 4.4 유속의 영향 = 83 4.5 공기 분사량의 영향 = 93 4.6 냉각면 온도의 영향 = 103 4.7 동결량의 무차원정리 = 113 4.8 결론 = 115 제 5 장 총결론 = 116 참고문헌 = 118 맺음말 = 12

통화바스켓 채권 : ECU가 동아시아에 주는 교훈

Thesis(master`s)--서울대학교 국제대학원 :국제학과(국제통상전공),2007.Maste

Famers' Preparation for Aging and Altive Policies

농업인의 노후준비에 대한 인식 정도와 노후준비 실태를 조사하여 농업인이 노후준비를 보다 충실하게 대처할 수 있는 정책대안 모색The purposes of this study are 1) to investigate farmers' preparation for aging, and 2) to suggest alternative policies to improve farmers' preparation for aging. The research methods were collection and analysis of existing data, and mail survey. Existing related data were collected by searching the data of related research institutes and governmental organizations. The mail survey was conducted among 1,075 local correspondents of Korea Rural Economic Institute(KREI). Descriptive statistics such as frequencies, percentage, means and cross-classification tables were used to organize and summarize the data. According to the results of the mail survey, only 55.9% of farmers were subscribed to the national pension, which means almost the other half of them could not be protected through the basic income safety net. Moreover, the subscribers were expected to receive only small pension benefits because they were applied to very low income level. The pension subscription rate of farmers' spouses was 42.9%. It was found that farmers were most concerned with health(59.0%), followed by preparation of living costs(25.9%), taking care of their children(7.9%), and medical costs(4.7%) for aging. Alternative policies to improve farmers' preparation for aging are as follows: 1) periodic investigation of farmers' preparation for aging, 2) governmental inducement for farmers' pension subscription, 3) encouragement of female farmers' pension subscription, 4) inducement for improving the level of farmers' pension subscription, 5) improvement of land pension system, 6) creation of jobs for elderly farmers, 7) construction of regular health control system, and 8) education and support of farmers' preparation for aging.제1장 서론 제1절 연구의 배경 및 목적 제2절 선행 연구 검토 제3절 연구의 범위와 내용 제4절 연구방법 제2장 노후준비의 이론적 검토 제1절 노후준비의 의의와 유형 제2절 농업인의 고령화 실태 제3절 고령화와 노후준비 방법 제3장 한국의 공적 노후보장대책의 실태와 문제점 제1절 소득보장정책 제2절 의료보장정책 제4장 농업인의 노후준비 실태 제1절 설문조사 응답 농업인의 일반적 특성 제2절 농업인의 국민연금 및 개인연금 가입 실태 제3절 농업인의 건강관리 실태 제4절 농업인의 노후 준비 실태 제5절 농업인의 노후 준비 계획 제5장 농업인 노후준비를 위한 정책대안 제1절 기본방향 제2절 정책대안 참고문헌 부

Current Situation of Senior Employment Projects in Rural Areas and Policy Tasks

현행 우리나라 소득보장제도는 농업이나 농촌의 특성을 제대로 반영하지 못하고 있어서 농촌주민의 노후생활을 보장하는 데는 많은 한계가 있다. 따라서 노인일자리는 농촌주민의 노후생활에 있어서 더욱 중요하며, 농촌 노인들의 적성과 능력에 적합한 일자리를 찾아주고 적절하게 지원할 필요가 있다. 노인일자리는 노인의 소득보장을 통해서 경제적인 도움을 줄 뿐만 아니라 노인들이 생산적인 노후생활을 영위하게 함으로써 노인의 삶의 질 향상에 기여한다. 이 연구의 목적은 농촌노인의 일자리 및 노인일자리 참여 실태와 요구사항,그리고 관련 정책의 현황과 문제점 등을 정확하게 파악하여 정책개선 과제를 도출하는 것이다.The purpose of this study is 1) to investigate the current situation and wants of rural elderly in senior employment projects, 2) to identify the current conditions and problems of related policies, and 3) to suggest policy tasks to improve the senior employment projects in rural areas. The research methods were the collection and analysis of existing data, field survey, and case study. A field survey was conducted among 450 rural elderly. Major policy tasks to improve the senior employment projects in rural areas are as follows: 1) reinforcement of policy propulsion system in senior employment projects, 2) tailor-made task propulsion based on the demand survey, 3) increase of participant’s wage and gradation by the type of senior employment, 4) propulsion of rural community typed senior employment projects, 5) reinforcement of education and publicity activities targeting on the rural elderly, 6) construction of organic cooperation system between senior employment projects and social economy programs, 7) improvement of working conditions for the manpower exclusively appointed for the post, and 8) policy tasks by the type of senior employment.Abstract 1 요 약 3 제1장 서론 13 제1절 연구의 배경 및 목적 15 제2절 선행연구 검토 16 제3절 연구의 범위와 내용 18 제4절 연구방법 19 제2장 농촌 노인일자리의 이론적 배경 23 제1절 농촌인구의 고령화 추이와 전망 25 제2절 농촌 노인일자리의 개념 정의 27 제3절 노인일자리 관련 이론 29 제3장 농촌노인들의 일자리 및 노인일자리 참여 실태 35 제1절 설문조사 응답자들의 일반적 특성 37 제2절 농촌노인들의 일자리 및 노인일자리 참여 실태 39 제3절 노인일자리 관련 농촌노인들의 요구사항 60 제4장 농촌 노인일자리 관련 정책의 현황과 문제점 65 제1절 농촌 노인일자리 관련 정책의 현황 67 제2절 농촌 노인일자리 관련 정책의 문제점 81 제5장 농촌 노인일자리 관련 국내외 우수 사례 89 제1절 국내의 우수 사례 91 제2절 외국의 우수 사례 101 제3절 정책적 시사점 108 제6장 농촌 노인일자리 관련 정책과제 111 제1절 기본방향 113 제2절 정책과제 114 참고문헌 121 부록 12

Implementation of digital baseband processor and system integration for 2.4GHz LR-WPAN (Low rate wireless personal area network) application

학위논문(석사) - 한국과학기술원 : 전기및전자공학전공, 2004.2, [ iii, 34 p. ]한국과학기술원 : 전기및전자공학전공