• 제목/요약/키워드: Cavity Length

검색결과 459건 처리시간 0.031초

Conceptual Design of the Superconducting Linac for KOMAC

  • Kim, Sang-Ho;Kim, Young-Hwan;Kim, Han-Sung;Lee, Kang ok;Chung, Kie-Hyung
    • 한국원자력학회:학술대회논문집
    • /
    • 한국원자력학회 1998년도 춘계학술발표회논문집(2)
    • /
    • pp.967-971
    • /
    • 1998
  • KOMAC (KOrea Multi-purpose Accelerator Complex) is the 1 Gev, 20 ㎃ proton linac. The superconducting linac for the high energy part acceleration from 100 MeV to 1 GeV is selected as a main candidate. As is well known, the superconducting linac has advantages for high current, high energy acceleration such as a large bore size, short accelerator length, and the RF efficiency. In this energy, the velocity of proton increases from $\beta$=0.87. For the design and fabrication simplicity, the cavity $\beta$ stages are divided into 3 parts. The maximum electric field in the cavity is designed below 20 ㎹/m. In this paper the design concepts and guides for this superconducting linac are introduced.

  • PDF

Low Threshold Current Density and High Efficiency Surface-Emitting Lasers with a Periodic Gain Active Structure

  • Park, Hyo-Hoon;Yoo, Byueng-Su
    • ETRI Journal
    • /
    • 제17권1호
    • /
    • pp.1-10
    • /
    • 1995
  • We have achieved very low threshold current densities with high light output powers for InGaAs/ GaAs surface-emitting lasers using a periodic gain active structure in which three quantum wells are inserted in two-wavelength-thick (2${\lambda}$ ) cavity. Air-post type devices with a diameter of 20~40${\mu}m$ exhibit a threshold current density of 380~410$A/cm^2$. Output power for a 40${\mu}m$ diameter device reaches over 11 mW. A simple theoretical calculation of the threshold and power performances indicates that the periodic gain structure has an advantage in achieving low threshold current density mainly due to the high coupling efficiency between gain medium and optical field. The deterioration of power, expected from the long cavity length of $2{\lambda}$, is negligible.

  • PDF

인공위성 탑재용 이중모드 도파관 필터 설계 및 제작에 관한 연구 (Design and Manufacture of a Dual Mode Waveguide Filter Loading On the Satellite)

  • 고영목;강원준;한수용;박종화;김춘길;라극환
    • 전자공학회논문지A
    • /
    • 제30A권10호
    • /
    • pp.1-11
    • /
    • 1993
  • A narrow-band dual TE$_{111}$ mode circular waveguide filter for Ku-Band satellite transponder was designed and manufactured based on a new model of the filter. We calculated the cavity size, pin polarizer depth and diameter, iris length and width, and used Bethe's Small Diffraction Theory and Chon's Correction Formular in order to obtain exact Result for each cavity. The designed dual model waveguide filter was manufactured with invar in order to maintain the thermal stability, and the filter performance was improved through the thermal test and vibration test to endure in the cosmic environment.

  • PDF

카본 도포에 따른 Cu-Epoxy 접촉면에서 발생하는 크랙방지에 관한 연구 (A Study on the Prevention of Crack Generated in Interface Cu and Epoxy with Painting of Carbon)

  • 송재주;김성훈;황종선;박종광;한병성
    • 한국전기전자재료학회논문지
    • /
    • 제14권7호
    • /
    • pp.578-583
    • /
    • 2001
  • The bushing for high voltage and large and power should endure weight of itself and force of pushing from contact with circuit breaker. Like this, epoxy mold bushing has to be strong without fault. However, the external circumstances and internal factors was caused by partial discharge, flashover and dielectric breakdown. Therefore, to remove external factor of defect and to prevent the internal cracks and cavity generated from the contraction on interface of Cu-Epoxy, we should form semi-conductive layer on Cu bar by carbon. Then, the PD properties and the insulation qualities of epoxy mold type bushing was able to improved by roles of cushions for the direction of diameter and by effects fo natural sliding like as separated from conductor for the direction of length. So, in this work, we could prove the method of semi-conductive layer in making the long conductor.

  • PDF

배기용 Fan Scroll에 대한 연구 (A Study on the Fan and Scroll for Ventilation)

  • 송성배;박성일;이준세
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2000년도 춘계학술대회논문집
    • /
    • pp.402-406
    • /
    • 2000
  • In the Over-The-Range, the outlet size is limited by the industrial standards. Therefor to enlarge the volume of cavity, the installation height of ventilation fan is become small, the system resistance is higher than before. For that reason, the important design variables such as the diameter of a fan, the scroll expansion angle, etc. which play the significant role on flow rate and noise, are confined. In this study, we made an experiment of the diameter of fans relation to scroll expansion angle and investigated flow rate of the length of fans in enlarged cavity volume of OTR, and then we designed the new scroll to improve the flow rate and noise level. As a result, flow rate increased to 110% compared to current scroll and the blade passing frequency of a fan is disappeared by inclined cut-off shapes.

  • PDF

훼밀리 몰드 성형에서 러너밸런스 결정을 위한 유동해석 (Flow Analysis to Determine Runner Balance in Family Injection Molding)

  • 김용조
    • 한국생산제조학회지
    • /
    • 제8권6호
    • /
    • pp.64-70
    • /
    • 1999
  • Family injection molding of plastic is widely used to enhance productivity. Runners for molded products in fami-ly injection molding have to be balanced so that each of the producs is filled completely at the same time,. In this study computer simulations were performed to determine balanced circular section runners in family injection molding with two cavities where each of he cavity shapes is like a case. It was found from the computer simula-tions that runner balance could be fulfilled only by modifying runner diameters. But in order to get more quality molded products other process factors such as flow length flow resistance shapes of products and etc, should be taken in to consideration for the design of a family injection molding process.

  • PDF

치근단절제술 실패의 일례 (A FAILED CASE OF ROOT RESECTION)

  • 이선형
    • 대한치과의사협회지
    • /
    • 제14권5호
    • /
    • pp.457-459
    • /
    • 1976
  • The author experienced a failed ase of root resection which qas performed on the abnormal upper right lateral incisor. The patient was 16year old female. Clinically the effected tooth had neither a carious cavity nor periondontal diseases, ut, a fistula was present on the gum tissue near the root apex. The roentogenogram revealed a pathological area around the apex of the tooth. The results of failed apicoectomy lead to following conclusions. 1. The operated tooth was a case of dense invaginatus which had two pulp cavities and two canals seperated along their entire length. 2. It was the main cause of failure that the second pulp cavity and root canal were not obturated.

  • PDF

3차원 재구성법을 이용한 수복물의 정량적 미세누출도 측정 (NEW QUANTITATIVE MEASURING TECHNIQUE FOR MICROLEAKAGE OF THE RESTORED TOOTH THROUGH 3D RECONSTRUCTION)

  • 하상윤;신동훈
    • Restorative Dentistry and Endodontics
    • /
    • 제29권5호
    • /
    • pp.413-422
    • /
    • 2004
  • Established microleakage tests have their own disadvantages. In this study, 3D reconstruction method was tried to overcome these disadvantages. Four types of microleakage tests were used and relationships among them were estimated: penetrated dye volume: marginal adaptability: degree of dye penetration and relative penetrated length to cavity wall. Twenty-four Class V cavities were bulk filled with composite (Esthet X) following surface treatments: N group (no treatment): E group (etching only): T group (etching + Prime & Bond NT). 50% silver nitrate was used as a dye solution after thermocycling ($5^{\circ}C{\;}&{\;}55^{\circ}C$, 1.000 times). Teeth were serially ground with a thickness of 0.2 mm. Volume of dye penetration was estimated from a three-dimensionally reconstructed image with a software (3D-DOCTOR). Percentage of margin without gap was estimated from SEM and degree of dye penetration and the relative length of dye penetration to overall cavity wall were also estimated. ANOVA and Scheffe test for dye volume, Kruskal-Wallis and Mann-Whitney test for marginal quality, Spearman's rho test for checking of relationships among methods were used. The results were as follows: 1. Dye penetration could be seen from several directions, furthermore, its volumetric estimation was possible. 2. Reverse relationship was found between dye volume and marginal quality (r = -0.881/ p = 0.004). 3. Very low relationship was seen between dye volume and two-dimensional tests (degree of dye penetration and relative length). However, 2D evaluation methods showed high relationship (p = 0.002-0.054) each other. 4. Three times vertical section could be recommended as a 2D test.

Evaluation of jet breakup length with a CFD code under steam generation condition in a pre-flooded cavity

  • Jeong-Hyeon Eom;Gi-Young Tak;In-Sik Ra;Huu Tiep Nguyen;Hae-Yong Jeong
    • Nuclear Engineering and Technology
    • /
    • 제55권7호
    • /
    • pp.2498-2503
    • /
    • 2023
  • When the reactor vessel is penetrated in a severe accident of light water reactor, the molten fuel-coolant interaction including the jet breakup occurs and the jet breakup length becomes one of the important parameters. Most numerical studies on jet breakup process have been carried out using dedicated computer codes. Some researchers are trying to apply commercial CFD codes to their investigations on comprehensive jet breakup process. However, the complexity of the phenomena limits the CFD application only to hydrodynamic aspects. In the present study, numerical analysis of jet breakup under vapor generation is pursued using the STAR-CCM + code. The obtained CFD prediction of the MATE09 experiment shows jet breakup progression patterns consistent to the images taken in the experiment. Further, the predicted positions of leading head, which determine the jet breakup length, are in good agreement with the MATE 09 data. The investigation of hydrodynamic effects on the jet breakup with higher jet velocity results in a stronger shear force and earlier jet breakup process even though there exists the vapor pocket around the corium jet. In future studies, the effect of vapor intensity on the jet breakup length would be investigated further by changing other parameters.

양력판(揚力板) 이론(理論)에 의(依)한 2차원(次元) 수중익(水中翼)의 초월(超越) 공동(空洞) 문제(問題) 해석(解析) (A Potential-Based Panel Method for the Analysis of A Two-Dimensional Super-Cavitating Hydrofoil)

  • 김영기;이창섭;이진태
    • 대한조선학회논문집
    • /
    • 제28권2호
    • /
    • pp.159-173
    • /
    • 1991
  • 본 논문에서는 양력판 이론을 사용하여 2차원 수중익에 발생한 비 대칭 초월 공동 문제를 포텐셜을 기저로하여 수치 해석하였다. 수중익과 공동 표면에 법선 다이폴을 분포하고 공동 표면에는 공동 형상을 찾기위하여 쏘오스를 분포하였다. 수중익 표면에서의 운동학적 경계조건은 수중익 내부에서의 전체 포텐셜이 0이라는 조건으로 대치하였고 공동 표면에서의 역학적 경계조건은 공동 표면에서의 접선 방향 속도가 일정하다는 조건으로 표현되었다. 표면에 특이 함수를 분포하여 포텐셜을 기저로하여 공동 문제를 해석하였기 때문에 압력 분포에 대하여, 특히 수중익의 앞날 근처에서는 양력면 이론에 의한 결과보다 더욱 향상된 정도의 결과를 얻었다. 본 이론은 먼저 주어진 공동 길이에 대하여 그에 상응하는 공동 형상 및 공동수를 구하였다. 좀더 좋은 결과를 얻기 위하여 새로이 계산된 공동 표면과 수중익 표면에 또 다시 특이 함수를 분포하여 그곳에서 경계 조건을 만족시킴으로써 새로운 공동 형상 및 공동수를 구하는 반복 계산을 수행하였다. 본 이론에 의한 계산 결과의 검증을 위하여 폭 넓은 수렴성 시험을 수행하였으며 특히, Geurst의 선형 이론에 의한 해석해 및 Wu의 비 선형 이론에 의한 해석해, 그리고 Acosta, Parkin, Meijer, Silberman, Waid의 실험 결과와 비교한 결과, 본 이론의 효용성을 입증하였다.

  • PDF