• 제목/요약/키워드: large patch

검색결과 277건 처리시간 0.027초

X-Band Phased Array Antenna Using Ferroelectric $(Ba,Sr)TiO_3$ Coplanar Waveguide Phase Shifter

  • Moon, Seung-Eon;Ryu, Han-Cheol;Kwak, Min-Hwan;Kim, Young-Tae;Lee, Su-Jae;Kang, Kwang-Yong
    • ETRI Journal
    • /
    • 제27권6호
    • /
    • pp.677-684
    • /
    • 2005
  • A phased array antenna was fabricated using four-element ferroelectric phase shifters with a coplanar waveguide (CPW) transmission line structure based on a $Ba_{0.6}Sr_{0.4}TiO_3(BST)/MgO$ structure. Epitaxial BST films were deposited on MgO (001) substrates by pulsed laser deposition. To attain the large differential phase shift and small losses for a ferroelectric CPW phase shifter, an impedance-matching-part adding technique between the effective transmission line and connecting cable was used. The return loss and insertion loss for this techniqueadapted BST CPW device were improved with respect to those for a normal BST CPW device. For an X-band phased array antenna system consisting of ferroelectric BST CPW phase shifters, power divider, dc block, patch antenna, and programmed dc power, the steering beam could be tilted by $15^{\circ}$ in either direction.

  • PDF

Nonlinear Analysis of Shell Structures by Improved Degenerated Shell Element (개선된 degenerated 쉘요소를 사용한 쉘구조의 비선형해석)

  • 최창근;유승운
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 한국전산구조공학회 1990년도 봄 학술발표회 논문집
    • /
    • pp.18-23
    • /
    • 1990
  • The paper is concerned with the elasto-plastic and geometrically nonlinear analysis of shell structures using an improved degenerated shell element. In the formulation of the improved degenerated shell element, an enhanced interpolation of transverse shear strains in the natural coordinate system is used to overcome the shear locking problems; the reduced integration technique in in-plane strains is applied to avoid membrane locking behavior; selective addition the nonconforming displacement modes improve the element performances. This element is free of serious locking problems and undesirable compatible or commutable spurious kinematic deformation modes and passes the patch tests. An incremental total Lagrangian formulation is presented which allows the calculation of arbitrarily large displacements and rotations. The resulting nonlinear equations are solved by the Newton-Raphson solution scheme. The versatility and accuracy of this improved degenerated shell element are demonstrated by solving several numerical examples.

  • PDF

A Design of UHF Sensor using Partial Discharge Measurement in GIS (부분방전 측정용 UHF센서의 설계)

  • Park, K.S.;Kim, J.B.;Song, Y.P.;Kim, D.S.
    • Proceedings of the KIEE Conference
    • /
    • 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
    • /
    • pp.28-30
    • /
    • 2002
  • The PD in GIS leads to a charge transfer and a voltage drop across the discharge area. They cannot be measure directly but we can measure electromagnetic wave made by PD. In generally, compared with VHF band, electromagnetic waves of UHF band have a low noise therefore, we can detect the real defect with several pC in GIS using UHF method. In this paper, the U-slot microstrip patch antenna for measuring PD signal in GIS is presented. the proposed UHF sensor are designed to have large band characteristics and unaffected structure for GIS operation.

  • PDF

Transaortic Closure of Ventricular Septal Defect in Congenitally Corrected Transposition of Great Arteries with Pulmonary Stenosis (대동맥절개를 퇘한 교정형 대혈관전위증의 심실중격결손 봉합)

  • An, Hong-Nam;Lee, Jong-Tae;Kim, Gyu-Tae
    • Journal of Chest Surgery
    • /
    • 제21권4호
    • /
    • pp.748-756
    • /
    • 1988
  • Transaortic closure of ventricular septal defect, suturing a patch on the morphological right ventricular side in patients with congenitally corrected transposition of great arteries might help to avoid postoperative complete heart block if the aorta is large and the subaortic conus is not well developed. In two patients[aged 6 and 16 years] with congenitally corrected transposition of great arteries, ventricular septal defect, and pulmonary stenosis, transaortic closure of ventricular septal defect was performed. No postoperative complete heart block resulted. One hospital death occurred because of sepsis who had underwent reoperation due to bleeding from the aortotomy site. Minimal aortic regurgitation developed in another patient.

  • PDF

Right Atrial Angiosarcoma -One Case Rreport- (우심방 맥관육종 -1례 보고-)

  • 박진상
    • Journal of Chest Surgery
    • /
    • 제28권7호
    • /
    • pp.713-716
    • /
    • 1995
  • A 75-year-old man was admitted to the hospital because of a pericardial effusion.After 3 L of blood-stained pericardial fluid was drained, clinical examination together with echocardiography and chest computed tomography showed a tumor in the right atrium. At operation a pedunculated vascular tumor was found with a broad base which was embedded in the atrial wall and extended into the pericardium.A wide resection was performed resulting in a large defect of the right atrial wall. The defect was reconstructed with a pericardial patch. The patient did well postoperatively, but bloody pleural effusion developed later, presumably because of pulmonary metastasis. The patient died 2 months after surgery as a result of respiratory failure.

  • PDF

Isolated Native Valve Endocarditis on Tricuspid Valve -A case report- (자기 삼첨판막에 발생한 고립성 심내막염의 외과적 치료 -1예보고-)

  • 홍준화;소동문;정조원;홍창호
    • Journal of Chest Surgery
    • /
    • 제32권12호
    • /
    • pp.1119-1122
    • /
    • 1999
  • Native valve endocarditis (NVE) without preexisting structural valve or congenital cardiac malformation especially in pediatric group is rare. A case of isolated tricuspid valve endocarditis in a 7-year-old child without any cardiac malformation is described. This child had suffered from fever and productive cough for 3 weeks. Blood culture grew Staphylococcus aureus. Fever was not controlled even with proper antibiotic treatment. Transthoracic echocardiogram and lung perfusion scan revealed a large vegetation on the tricuspid valve with multiple embolism Surgical procedures included vegetectomy partial cusps resection and pericardial patch valvuloplasty. Th patient was in NYHA class I during follow up.

  • PDF

Effect of Nifedipine in Acute Episode of Postoperative Pulmonary Hypertension and Right Heart Failure (심장 수술후에 발생한 급성 폐동맥 고혈압및 우심부전증 환자에서 nifedipine의 효과)

  • Choe, Sun-Ho;Choe, Jong-Beom;Yun, Hyang-Seok
    • Journal of Chest Surgery
    • /
    • 제25권7호
    • /
    • pp.736-738
    • /
    • 1992
  • We report the successful use of Nifedipine in the treatment of acute pulmonary hypertension in an young child after a cardiac operation. This patient had undergone patch closure of large ventricular septal defect. She had signs of severe pulmonary artery hypertension unresponsive to hyperventilation, oxygenation, sedation, and a myriad of vas-oactive drugs. Nifedipine, 0.3mg /kg every 4 hours, effectively treated her pulmonary artery hypertension and allowed for a smooth postoperative course and positive outcome. The drug lowered systemic diastolic pressure, but not systolic pressure.

  • PDF

An Adult Right-sided Bochdalek Hernia Accompanied with Hepatic Hypoplasia and Inguinal Hernia

  • Choi, Yun Kyung;Ahn, Jae Ho;Kim, Kwan Chang;Won, Tae Hee
    • Journal of Chest Surgery
    • /
    • 제45권5호
    • /
    • pp.348-350
    • /
    • 2012
  • We herein report a very rare case of adult right-sided Bochdalek hernia accompanied with hepatic hypoplasia and inguinal hernia. A 29-year-old man was admitted with right-sided pneumothorax. A computed tomography was performed and revealed large right sided Bochdalek hernia with hepatic hypoplasia. Under thoracolaparotomy, the defect was closed with Gore-Tex soft tissue patch. After the operation, left-sided inguinal hernia was found. However, it turned out that it had been present during infancy and spontaneously resolved during adolescence. This is the first report of right-sided Bochdalek hernia with hepatic hypoplasia and inguinal hernia in an adult.

Three Species of Acrolepiopsis (Lepidoptera, Glyphipterigidae, Acrolepiinae) New to Korea

  • Sohn, Jae-Cheon;Kim, Sung-Soo;Choi, Sei-Woong
    • Animal Systematics, Evolution and Diversity
    • /
    • 제34권4호
    • /
    • pp.190-193
    • /
    • 2018
  • Three species of Acrolepiopsis: A. issikiella (Moriuti, 1961), A. japonica Gaedike, 1982, and A. postomacula (Matsumura, 1931), are recorded from Korea for the first time. Acrolepiopsis issikiella is characterized by having the white costal strigulae and a large dorsal patch on the forewing. Acrolepidopsis japonica is the smallest congener in Korea. Acrolepiopsis postomacula is the only Korean species of Acrolepiinae associated with Hosta. Distributions and larval biology of the three species are summarized. Two species, A. issikiella and A. japonica, are potential pest species of yam-cultivating farms in Korea. Superficial and genital features of the species, if available, are illustrated.

Natural frequency error estimation for 3D brick elements

  • Stephen, D.B.;Steven, G.P.
    • Structural Engineering and Mechanics
    • /
    • 제5권2호
    • /
    • pp.137-148
    • /
    • 1997
  • In computing eigenvalues for a large finite element system it has been observed that the eigenvalue extractors produce eigenvectors that are in some sense more accurate than their corresponding eigenvalues. From this observation the paper uses a patch type technique based on the eigenvector for one mesh quality to provide an eigenvalue error indicator. Tests show this indicator to be both accurate and reliable. This technique was first observed by Stephen and Steven for an error estimation for buckling and natural frequency of beams and two dimensional in-plane and out-of-plane structures. This paper produces and error indicator for the more difficult problem of three dimensional brick elements.