• Title/Summary/Keyword: 4,\

Search Result 427,875, Processing Time 0.351 seconds

A Study on the Sailing Speed of Ancient Ships - especially on the average speed and the effect of the wind, the tide, and the man-power at the oar - (고대 선박의 항해속도 연구 - $\ll$고려도경$\gg$을 중심으로-)

  • Yoon, Il-Young
    • Journal of National Security and Military Science
    • /
    • s.7
    • /
    • pp.155-231
    • /
    • 2009
  • Xu-Jing(徐競) an official of the Song(宋), a medieval Kingdom of China, wrote a book titled $\ll$Koryo Tu Jing(高麗圖經)$\gg$ which explains his travel to the Koryo as a member of diplomatic mission in 1123. $\ll$Koryo Tu Jing$\gg$ is the record of his personal experience in Koryo with many explanatory illustrations and especially contains 5 months' voyage record of his diplomatic fleet. His fleet set sail at a port located in the Ding Hai Xian(定海縣), Ming Zhou(明州) via a few islands of Koryo [Hyup Kye San(俠界山) , the Kun San Do(群山島) , the Ja Yon Do(紫燕島) , the Keup Su Mun(急水門) in Kang Hwa Gun(江華郡) and the Hap Gul(蛤窟) ] and finally arrived the Port Ye Song Hang(禮成港) . According to the Xu-Jing's record his fleet sailed the sea with the help of the favorable seaward winds and tides as the usual way of ancient sailing. The Xu- Jing's Fleet sailed the sea between the Mei Cen(梅岑), Ming Zhou(明州) of China and the Hyup Kye San(俠界山) of Koryo from about 5:00 a.m., May 24th(of the lunar calendar) to about 5:00 p.m., June 2nd. At this section, the average speed of the seaward winds was 19.45km/h and the average speed of the fleet which sailed only by the power of the winds was 6.29km/h. This means that 32.3% of the favorable seaward winds' speed was equal to the speed of the ancient fleet which sailed only by the power of the favorable seaward winds. The fleet sailed the sea between the Ja Yon Do(紫燕島) and the Keup Su Mun(急水門) from about 9:00 a.m., June 10th to about 1:00 p.m., the same day. At this section the fleet sailed by the power of tides in addition to the favorable seaward winds without oaring. The average speed of the winds was not different from that of former section and the average speed of the tides was 1.937km/h. And at this section the average speed of the fleet increased by 0.41km/h than that of the former section. This means that 21.1% of the speed of the tides was equal to the increased speed of the ancient fleet by virtue of the tides. The fleet sailed the sea between Keup Su Mun(急水門) and the Hap Gul(蛤窟) from about 1:00 p.m., June 10th to about 3:00 p.m., the same day. At this section, there were no seaward winds and the fleet sailed only by the powers of tides and oaring. And at this section, the tide increased the average speed of the fleet by 0.3114km/h and the fleet could sail at the speed of 4.3km/h. So we can conclude that the average speed of ancient fleet without any influences of the seaward winds and tides was 3.98 km/h. We can make use of the various sailing speeds of ancient fleets when judging their maritime activities. If we make use of the various sailing speeds of the ancient fleets as calculated in this article, we will be able to get various important informations about the certain ancient fleet's maritime maneuver. For example, we can infer the sailing routs of a certain fleet and the time when the fleet passed a certain spot by making use of the various sailing speeds of the ancient fleet. In this article I did not take account of the shapes of ships that consist of the ancient fleets and the sizes of the various ships and fleets. It was because that such factors would not change the foresaid conclusions seriously.

  • PDF

A Comparative Study on Communication of Agricultural Innovation (농업 기술 전파 커뮤니케이션에 관한 비교 연구)

  • Kim, Sung-Soo
    • Journal of Agricultural Extension & Community Development
    • /
    • v.7 no.1
    • /
    • pp.121-136
    • /
    • 2000
  • This study reports on a comparison between the Korean diffusion of agricultural innovation or extension service and the cooperative extension service in the United States of America. It focuses on relevant differences between the two systems and provides recommendation for improvement of the Korean system to insure success in important areas related to the diffusion of agricultural innovations. After a comparative study on diffusion of innovations it is clear that: in order to have a productive agriculture that makes effective and efficient use of natural resources and helps achieve sustainability goals, a mechanism that delivers knowledge to agricultural communities must be established and maintained. This mechanism is clearly an agricultural extension service that is cooperatively funded by federal, state and local governments and that insures participation of constituents in the process of establishing priorities and evaluating achievements. The success of US agriculture, the most productive in the world, is to a large degree to the Cooperative Extension Service. Based on the results of this study and the differences of the United States and Korea, the following recommendations should be emphasized for more effective communication for agricultural innovation and rural development in Korea: 1) In order to insure that extension educators are high caliber professional individuals, it is important to establish a system that nationally recognizes these individuals as such, and that provides a professional development path. 2) The results of the decision of transfer of extension educators to local governments has not yielded positive outcomes, especially in terms of professional status. It is clearly demonstrable that valuable professionals are leaving the service, that local governments do not have the will and resources to implement a successful extension program. 3) Because of the critical importance of diffusing innovations to agricultural producers in order to insure and quality and steady food supply, it is of critical importance that these issues be addressed before the extension service is further deteriorated. Given the cement situation, it is clear that the extension service should become nationally supported again in cooperation with local and state governments and that extension professionals be given appropriate rank at the national level, commesurate with their peers in research and teaching. 4) The common current committee practice of lengthy reporting and short discussion needs to be changed to one that results in char, brief and substantive action oriented goals. Joint participation by researchers, extension educators and farmers should be encouraged in planning, implementation and evaluation of communication for agricultural innovations. Roles and functions of committees for institutional cooperation, and or agricultural extension committees should be enlarged. 5) Extension educators should be encouraged to adopt new communication technologies to improve their diffusion of innovations methods. Agricultural institutions and organizations should be encouraged to adopt farmer-first and or client-oriented approach in agricultural extension and diffusion of agricultural technologies. The number, complexity and rapid change of information in agricultural extension require the development of a computer based information and report system to support agricultural extension. 6) To facilitate and expand the further development of communication for agricultural innovation and rural development, agricultural communication programs in universities especially in colleges of agriculture and life sciences. 7) To strengthening the sense of national and social responsibility communication for agricultural innovation and rural development among students in agricultural colleges and universities through participation in learning activities by proactive recruitment. 8) To establish and reinforce a policy that insures participation in communication for agricultural innovation and regal development activities. 9) To improve further development of communication for agricultural innovation and rural development in Korea, more research activities should be encouraged.

  • PDF

A Study on the Presence of Post-Miesianism and Its Future (Post-Miesianism의 실체와 미래에 대한 연구)

  • Lee, Sang-Jin
    • Journal of architectural history
    • /
    • v.10 no.4 s.28
    • /
    • pp.77-92
    • /
    • 2001
  • 현대의 건축시기는 다원성의 시기 또는 복합성의 시기라고 불리운다. 모더니즘과 포스트모더니즘의 시기를 거치며 다양한 형태적 실험의 과정을 겪었고 수많은 이데올로기와 이론들로 무장된 논쟁의 역사도 갖게 되었다. 이러한 현대건축의 다양성은 건축디자인이라는 전문직의 사회에 기여하는 역할을 반추(反芻)함과 동시에 다변하는 인간사고의 역동성을 반영하고 있다. 건축관련 책자나 저널 등에서 흔히 발견할 수 있는 Neo-Classicism, Deconstructivism, Minimalism, High-Tech, New Moderns 등등의 건축양식들은 스타일을 지칭하는 언어라기보다는 건축적 사고를 지칭하는 언어라고 할 수 있다. 결국 건축디자인이라는 작업은 인간을 둘러 싼 건조환경의 생성에서 출발하는 것이므로 건축적 사고방식은 그 시기의 사회현상과 밀접한 관계를 맺게 된다. 20세기 말부터 불어닥친 디지털 문화의 사회변혁은 전 세계를 하나의 채널로 엮게 되었고, 이러한 영향들은 지역과 민족, 그리고 종교적인 요소들까지도 혼합하여 국경을 초월한 미래의 새로운 이상들을 꿈꾸게 되었다. 19세기 산업혁명과 함께 급속히 벨라진 인류문명의 진보는 필수적으로 세계화를 동반하는 것이고, 세계화와 지역성사이의 괴리를 통해 나타나는 문화적 비판과 충돌은 아직도 진행상태인 것이다. 세계화라는 통염은 문명의 보편성을 기반으로 하며 전통문화의 파괴가 뒤따를 수밖에 없는데, 현재와 같이 IT혁명을 통해 급속도로 빨라진 세계문화의 교류는 한 국가가 뿌리를 내리고 있는 문화적 유산이라는 토양을 포기하여야 할 단계에 와 있다고 논평할 정도이다. 여기서 건축은 문화적 상징으로 작용하게 되는데, 그것이 심미적이든 관습적이든 또는, 경제적이든 건축가는 해답의 제시라는 임무에 직면하게 된다. 20세기에 진행된 모더니즘의 건축은 구조와 공간에 대한 고전건축의 숙원을 고덕건축이 이룬 것처럼 15세기 르네상스 시대로부터 진행된 형태와 공간, 기능, 그리고 아름다움과 기술(technology) 또는 경제성 등에 대한 건축적 의문과 탐구를 일단락지었다고 할 수 있다. 이러한 모더니즘의 한복판에 Mies van der Rohe라는 거장이 깊은 발자국을 남기며 한 시대를 이루었고 그가 남긴 시대정신의 이념과 가치를 Miesianism이라고 부른다. 실용성과 도덕성을 근본으로 하는 Miesianism은 대중에 호소하는 미적 표현주의를 부정하고 지역정서를 중시하는 문맥적 접근방식을 경시함으로써 보편화라는 현상을 불러일으킨 국제주의 양식의 한 부류로 비판을 받아왔다. 즉, Miesianism의 단순하고 강렬한 외형적 요소는 그것이 내포하는 기술적 합리성이나 공간적 완결성을 무시한 채 전 세계에 영향을 미쳤고 동시에 지역적 저항을 받게 되었다. 시카고 및 전 세계의 Miesian들, 즉 Mies van der Rohe의 제자들이나 그로부터 영향을 받은 수많은 건축가들은 이러한 저항과 비판에 직면하게 되며 새로운 사고의 시대적 요구 앞에 고뇌하게 된다. 한국에서는 1978년 Mies van der Rohe의 제자인 김종성이 미국에서 서울로 돌아와 '서울건축컨설탄트'를 설립하며 본격적으로 Miesianism의 규범적 건축론을 설파하기 시작하였다. 이른바 시카고 국제주의학파의 건축전수라고 할 수 있는데 '서울건축컨설탄트'를 통하여 배출된 김종성의 제자들은 명쾌하고도 간결한 건축해법의 경험을 토대름대로의 정체성을 갖고자 노력하였으나 결국 다원적 가치를 요구하는 시대적 흐름 속에 혼란을 겪고 있는 것 또한 사실이다. 본 연구는 Miesianism의 기원을 밝히고 그것의 실수와 오류를 밝힘과 동시에 현대의 여러 가지 건축유형들과 비교하여 봄으로써 Post-Miesianism의 실체와 그 미래에 대하여 고찰하여 보고자 한다. 미스의 유산이라고 할 수 있는 Miesianism의 요체는 첫째, Schinkel로부터 이어받은 시대정신의 사명감, 둘째, Berlage가 전해준 전문가로서의 도덕성을 바탕으로 하여 이루어진 기술적 합리성의 실현, 그리고 마지막으로 그 당시의 추상예술에 대한 이해로써 받아들인 nee-Suprematism의 아방 가르데적인 자세라고 할 수 있다. 그러나 이것들을 전파하고 수용하는 과정에서 미스적인 단순하고 명쾌한 외관이 더욱 강한 인상을 남기게 되었고 또한 미스가 현대성의 본질이라고 믿는 기술의 전수는 모든 외관을 동일하게 만드는 International Style로서의 보편적 획일성을 초래하였다. Mies van der Rohe의 강력하고 규범적인 dogma는 그의 제자들에게는 강렬한 카리스마로 각인되었고, Mies가 원한 것이 아닐지라도 그들을 하나의 틀 속에 가두는 영향력을 행사하였다. 2세대이든 3세대이든 기술적 합리성과 추상적 단순미라는 믿음을 맹목적으로 추종할 때 그들은 Miesian으로 남아있게 되며, 거기서 벗어났을 때 non-Miesian, 또는 배신자로 취급하기까지 하였다. 이것은 미스의 제자들에게 강한 족쇄가 되어 형태적 또는 개념적 변화의 시도를 어렵게 하였고 시대적 요구에 부응하지 못한다는 평가에 이르게 되었다. 문화의 다양성과 역동성을 인정함과 동시에 Miesianism에 대한 새롭고 시대에 적합한 해석을 기대하게 되는데, 이러한 기대 속에서 우리는 Post-Miesianism이라는 새로운 유형을 엿볼 수 있게 된다. Post-Miesianism의 징후를 현대의 다양한 건축유형에서 발견할 수 있는데, High-Tech의 구축적이고 정밀한 건축 기술적 해법과 Minimalism의 반복성을 통한 추상미의 표현 등에서 뿐만이 아니라 Post-Modernism의 인간성의 추구나 문맥적 고려, 또는 해체주의의 형이상학적이고 아방가르데적인 실험주의 정신까지조차 Post-Miesianism이 공유할 수 있는 부분이 있다고 보여진다. 또한, 미스의 영향이 2세대, 3세대의 건축가들에게 미치면서 여러 방향으로 변질되어 가는 것을 우리는 발견할 수 있으며 그러한 시대성에 적응하는 시도들이야말로 새로운 미래를 향한 Post-Miesianism의 실체인 것이다. Mies가 말하였듯이 한 시대의 끝은 그 시대가 완전히 이해되었을 때이며, 모더니즘의 숙제는 아직 해결되지 않았으므로 Miesianism의 탐구는 Post-Miesianism이라는 새로운 주제로 계속될 것이다. 이를 통하여 21세기 디지털 문명의 시대 속에서 현대건축이 안을 수밖에 없는 보편성과 지역성의 충돌이라는 문제의 해결에 한 발걸음 다가갈 수 있기를 기대하여 본다.

  • PDF

Effect of Staged Education Program for Hypertension, Diabetes Patients in a Community (Assessment of Quality of Life Using EQ-5D) (일 지역에서의 EQ-5D를 이용한 고혈압·당뇨병 교육프로그램 이수자의 삶의 질 평가)

  • Lee, Jung Jeung;Lee, Hye Jin;Park, Eun Jin
    • Journal of agricultural medicine and community health
    • /
    • v.39 no.1
    • /
    • pp.37-45
    • /
    • 2014
  • Objective: This study was conducted in order to evaluate an education program for cardio-cerebrovascular high-risk patients. Methods: To evaluate patients' quality of life, EQ-5D was used and an organized survey was conducted via calls and interviews for hypertension, diabetes patients who had visited the KHyDDI(Korea Hypertension Diabetes DaeguInitiative) education center or 70 clinics through out the nation. Results: The subjects included 537 patients, 320 of who were in the clinic education and 217 of who were in the education center program. Sixty eight of the subjects went through the EQ-5D evaluation before and after the education program. In the EQ-5D index distribution of their quality of life before the education program, there was a statistically significant difference in gender(p<0.001) with higher points among males. Regarding age, there was a statistically significant difference between those aged over 65 years and under 65(p<0.001), with higher points in the group under the age of 65. Further, the EQ-5D 5 scope index was statistically significant different before and after receiving the education(p<0.05). Conclusion: Therefore, the KHyDDI staged education program is effective for improving the quality of life. Moreover, it could contribute to the complications of the disease through a variety of approaches by considering both gender and age.

Discussion by UNCITRAL for Development of International Commercial Conciliation and Arbitration Systems (국제상사조정 및 중재제도 개선에 관한 UNCITRAL 논의동향)

  • Lee, Kang Bin
    • Journal of Arbitration Studies
    • /
    • v.10 no.1
    • /
    • pp.3-25
    • /
    • 2000
  • At its thirty-second session in 1999, the UNCITRAL had before it the requested note entitled "Possible future work in the area of international commercial arbitration." After concluding the discussion on its future work in the area of international commercial arbitration, it was agreed that the priority items for the working group should be conciliation, requirement of written form for the arbitration and enforceability of interim measures of protection. the Commission entrusted the work to the Working Group on Arbitration which held its thirty-second session at Vienna from 20 to 31 March 2000. The Working Group discussed agenda item 3 on the basis of the report of Secretary General entitled "Possible uniform rules on certain issues concerning settlement of commercial disputes : conciliation, interim measures of protection, written form for arbitration agreement." At its thirty-three session in 2000, the UNCITRAL had before it the report of Secretary General on agenda item 3 discussed by the Working Group. The Working Group discussed the issues relating to certain aspects of conciliation proceedings ; (1) Admissibility of certain evidence in subsequent judicial or arbitral proceedings ; (2) Role of conciliatior in arbitration or court proceedings ; (3) Enforceability of settlement agreements reached in conciliation proceedings ; (4) Other possible items for harmonized treatment : a) Admissibility or desirability of conciliation by arbitrators b) Effect of an agreement to conciliate on judicial or arbitral proceedings c) Effect of conciliation on the running of limitation period d) Communication between the conciliator and parties ; disclosure of information e) Role of conciliator. It was generally considered that decisions as to the form of the text to be prepared should be made at a later stage when the substance of prepared solutions would become clearer. However, it was noted that model legislative provisions seemed to be appropriate form for a number of matters proposed to be discussed in the area conciliation. There was general support in the Working Group for the proposition to perpare a legislative regime governing the enforcement of interim measures of protection ordered by arbitral tribunals. It was generally considered that legislative regime should apply to enforcement of interim measures issued in arbitration taking place in State where enforcement was sought as well as outside that State. It was generally observed that there was a need for provisions which conformed to current practice in international trade with regard to requirements of written form for arbitration agreement. The view was adopted by the Working Group that the objective of ensuring a uniform interpretation of the form requirement that responded to the needs of international trade could be achieved by : preparing a model legislative provision clarifying, for avoidance of doubt, the scope of article 7(2) of the UNCITRAL Model Law on International Commercial Arbitration : and adopting a declaration, resolution or statement addressing the interpretation of the New York Convention that would reflect a broad understanding of the form requirement. There was general agreement in the Working Group that, in order to promote the use of electronic commerce for international trade and leave the parties free to agree to the use of arbitration in the electronic commerce sphere, article II(2) of the New York Convention should be interpreted to cover the use of electronic means of communication as defined un article 2 of the Model Law on Electronic Commerce and that it required no amendment to do that. The UNCITRAL may wish to consider to the desirability of preparing uniform provisions on any of those issues concerning conciliation and arbitration proceedings, possibly indicating whether future work should be towards a legislative text or non-legislative text.

  • PDF

FACTORS OF MENTALLY HANDICAPPED CHILDREN AND THEIR FAMILY ASSOCIATED WITH THE QUALITY OF LIFE AND THE EMOTIONAL WELLBEING OF THEIR MOTHERS (장애 아동의 행동 특성과 가족환경이 어머니의 정서적 안녕감과 삶의 질에 미치는 영향)

  • Lee, Yong-Ho;Chung, Yong-Kyoon;Cho, Soo-Churl;Koo, Young-Jin
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
    • /
    • v.10 no.1
    • /
    • pp.100-112
    • /
    • 1999
  • Objective:In life-long disabilities like autism and mental retardation, the authors thought that it is important for clinician to consider the quality of life of a primary caregiver for long-term management and prognosis. This study was to investigate the factors of children and family environment affecting the quality of life and depression in mothers with autistic and/or mentally retarded children. Methods:41 autistic and/or mentally retarded children aged 5-12 years with their mothers were surveyed from September, 1998 to January, 1999, with K-CBCL, K-BDI, K-FES, and K-SBQOL scale and compared with data from 35 normal control subjects. Results:1) Total K-BDI and K-SBQOL scores of mothers with mentally handicapped children were significantly poorer than the scores of normal control group. Independence, intellectual/cultural orientation and active recreation subscales of K-FES in mentally handicapped children were significantly decreased than those in normal control group. 2) Total K-BDI score of mothers with mentally handicapped children was correlated with their children’s behavioral problems, especially internalizing and thought symptoms, and with family cohesion, expressiveness, conflict and independence. 3) Totol K-SB quality of life score of mothers with mentally handicapped children was correlated with their children’s behavioral problems, especially attention problem, and with family cohesion, conflict, independence, intellectual/cultural orientation, and moral-religional emphasis. 4) The quality of life of mothers with mentally handicapped children was predicted by attention problem($R^2$=.36, p=.000) and social competence($R^2$=.07, p=.038) in children and family cohesion ($R^2$=.16, p=.001). 5) Depression of mothers with mentally handicapped children was predicted by internalizing symptom ($R^2$=.21, p=.003) and thought disorder($R^2$=.06, p=.048) in children and family cohesion($R^2$=.14, p=.008). Conclusion:Reducing behavioral problems and family therapeutic intervention in autistic and mentally retarded children can improve the quality of life of primary caregivers and long-term prognosis of the children, although those are not curative.

  • PDF

COMPARISON BETWEEN ATTENTION DEFICIT HYPERACTIVITY DISORDER AND MANIA IN CHILDREN AND ADOLESCENTS (주의력결핍과잉행동장애와 소아, 청소년기 조증의 비교 연구)

  • Sung, Yang-Sook;Hong, Kang-E;Cho, Soo-Churl;Nam, Min
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
    • /
    • v.10 no.1
    • /
    • pp.91-99
    • /
    • 1999
  • Objects:It is difficult to differentiate between attention deficit hyperactivity disorder(ADHD) and mania because of similar symptoms and atypical symptoms of mania in children and adolescents. The purpose of this study is to identify the characteristics and to clarify the relationship by comparing the clinical features and comorbidities of ADHD and manic patients. Methods:The subjects consisted of 35 patients with ADHD and 19 manic patients. To Compare the characteristic symptoms between the two disorders, we selected 29 patients with ADHD and 14 patients with manic disorders. 6 ADHD patients who had manic disorders as comorbid disorder, and 5 manic patients who had ADHD as comorbid disorders were manic disorders were excluded. Results:1) There were significant differences in ages of onset and state anxiety scale scores, birth weights, numbers of perinatal problem, gestational ages, school behavioral problems between ADHD patients and manic patients(p<0.01). 2) There were significant differences in loses things(p<0.05) of ADHD-symptoms and grandiosity(p<0.01), decrease in sleep(p<0.05), delusions(p<0.01), hallucinations(p<0.05) of mania-symptoms between ADHD patients and manic patients. 3) The comorbid disorders of ADHD patients are significantly high(p<.05) than that of manic patients in major depression. 4) The familial loading of manic patients are significantly high(p<.05) than that of ADHD patients in mood disorder. Conclusions:The above results suggest that ADHD and mania are different disorders, considering the significant differences of clinical features and characteristics, familial loadings of the two disorders.

  • PDF

A Study on the Precise Lineament Recovery of Alluvial Deposits Using Satellite Imagery and GIS (충적층의 정밀 선구조 추출을 위한 위성영상과 GIS 기법의 활용에 관한 연구)

  • 이수진;석동우;황종선;이동천;김정우
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
    • /
    • 2003.04a
    • /
    • pp.363-368
    • /
    • 2003
  • We have successfully developed a more effective algorithm to extract the lineament in the area covered by wide alluvial deposits characterized by a relatively narrow range of brightness in the Landsat TM image, while the currently used algorithm is limited to the mountainous areas. In the new algorithm, flat areas mainly consisting of alluvial deposits were selected using the Local Enhancement from the Digital Elevation Model (DEM). The aspect values were obtained by 3${\times}$3 moving windowing of Zevenbergen & Thorno's Method, and then the slopes of the study area were determined using the aspect values. After the lineament factors in the alluvial deposits were revealed by comparing the threshold values, the first rank lineament under the alluvial deposits were extracted using the Hough transform In order to extract the final lineament, the lowest points under the alluvial deposits in a given topographic section perpendicular to the first rank lineament were determined through the spline interpolation, and then the final lineament were chosen through Hough transform using the lowest points. The algorithm developed in this study enables us to observe a clearer lineament in the areas covered by much larger alluvial deposits compared with the results extracted using the conventional existing algorithm. There exists, however, some differences between the first rank lineament, obtained using the aspect and the slope, and the final lineament. This study shows that the new algorithm more effectively extracts the lineament in the area covered with wide alluvlal deposits than in the areas of converging slope, areas with narrow alluvial deposits or valleys.

  • PDF

Theoretical Analysis of FBARs Filters with Bragg Reflector Layers and Membrane Layer (브래그 반사층 구조와 멤브레인 구조의 체적 탄성파 공진기 필터의 이론적 분석)

  • Jo, Mun-Gi;Yun, Yeong-Seop
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.39 no.4
    • /
    • pp.41-54
    • /
    • 2002
  • In this study, we have analyzed the effects of the membrane layer and the bragg reflector layers on the resonance characteristics through comparing the characteristics of the membrane type FBAR (Film Bulk Acoustic Wave Resonator) and the one type bragg reflector layers with those of the ideal FBAR with top and bottom electrode contacting air by using equivalent circuit technique. It is assumed that ZnO is used for piezoelectric film, $SiO_2$ are used for membrane layer and low acoustic impedance layer, W are used for the high acoustic reflector layer and Al is used for the electrode. Each layer is considered to have a acoustic propagation loss. ABCD parameters are picked out and input impedance is calculated by converting 1-port equivalent circuit to simplified equivalent circuit that ABCD parameters are picked out possible. From the variation of resonance frequency due to the change of thickness of electrode layers, reflector layers and membrane layer it is confirmed that membrane layer and the reflector layer just under the electrode have the greatest effect on the variation of resonance frequency. From the variation of resonance properties, K and electrical Q with the number of layers, K is not much affected by the number of layers but electrical Q increases with the number of layers when the number of layers is less than seven. The electrical Q is saturated when the number of layers is large than six. The electrical Q is dependent of mechanical Q of reflector layers and membrane layer. Both ladder filter and SCF (Stacked Crystal Filters) show higher insertion loss and out-of-band rejection with the increase of the number of resonators. The insertion loss decreases with the increase of the number of reflector layers but the bandwidth is not much affected by the number of reflector layers. Ladder Filter and SCF with membrane layer show the spurious response due to spurious resonance properties. Ladder filter shows better skirt-selectivity characteristics in bandwidth but SCF shows better characteristics in insertion loss.

Orientation, Surface Roughness and Piezoelectric Characteristics of AlN Thin Films with RF Magnetron Sputtering Conditions (RF 마그네트론 스퍼터링 공정 조건에 따른 AlN 박막의 배향성, 표면 거칠기 및 압전 특성에 관한 연구)

  • Bang Jung-Ho;Chang Dong-Hoon;Kang Seong-Jun;Kim Dong-Guk;Yoon Yung-Sup
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.43 no.4 s.346
    • /
    • pp.1-7
    • /
    • 2006
  • AlN thin films have been fabricated by using RF magnetron sputtering method and their crystal orientations, microstructures and piezoelectric properties have been investigated with variation of the $Ar/N_2$ gas ratio and the substrate temperature. Particularly, when the $Ar/N_2$ gas ratio and the substrate temperature are 10/10 (sccm) and $400^{\circ}C$, respectively, the AlN thin film exhibits the highest (002) orientation. The result of the surface roughness measurement by using AFM shows that the surface roughness becomes better as the partial pressure of $N_2$ increases at the substrate temperature of $400^{\circ}C$ and it becomes the smallest value of 2.1 nm when $Ar/N_2$ is 0/20 (sccm). The AFM measurement also shows that when $Ar/N_2$ is 10/10 (sccm) shows that surface roughness becomes better as the substrate temperature increases from room temperature up to $300^{\circ}C$ and then it becomes worse as the substrate temperature goes up from $300^{\circ}C$. At the substrate temperature of $300^{\circ}C$ and $Ar/N_2$=10/10 (sccm), the surface roughness is 3.036 nm. The piezoelectric constant ($d_{33}$) of AlN thin film is measured by Pneumatic probe method. The measurement shows that the AlN thin film with the highest (002) orientation, fabricated at $Ar/N_2$=10/10 (sccm) and the substrate temperature of $400^{\circ}C$, has the best Piezoelectric constant ($d_{33}$) of 6.01 pC/N.