• 대한기계학회논문집A
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• 제41권4호
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• pp.333-336
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• 2017

스피커 진동판은 고유 특성에 의해 분할진동을 발생 시킨다. 이 분할진동은 진동판의 형상 변화를 가져올 정도로 뚜렷한 영향을 주는데, 본 논문에서는 IT 분야의 첨병인 스마트 폰을 포함한 초박형 멀티미디어 기기에서 많이 사용되는 마이크로 스피커를 그 대상으로 삼는다. 마이크로 스피커는 일반적인 스피커와 다른 평판형의 구조적인 형태와 공간적인 제약이 존재한다. 특히 구동 공간이 밀폐형으로 설계되어 무빙 코일에서 발생하는 열의 냉각이 열악하고 보조적인 서스펜션 구조를 갖추기 어렵다. 본 연구에서는 진동판의 열전달과 분할진동 모드의 연관성을 연구한다. 이를 위해 진동판의 레이저 스캔을 통한 분할진동 측정과 열화상 카메라 촬영을 통한 열변화 측정의 두 단계로 나누어 실험을 진행한다. 이를 통해 특정 주파수 범위에서 분할진동 모드와 열전달 형태를 비교함으로써, 열화상 카메라를 통한 촬영 결과로 진동판 분할진동 모드의 경향성을 빠르게 예상할 수 있어, 마이크로 스피커의 최적 설계에 도움이 되는 지표를 제공할 수 있을 것으로 기대한다.

• Structural Engineering and Mechanics
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• 제86권4호
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• pp.461-472
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• 2023

This paper proposes a novel method for increasing the distortional frame rigidity of off-rail box girder bridges for cranes by reinforcing the diaphragm with staggered truss. The study starts by using the Matrix Displacement Method to determine the shear angle of the staggered truss diaphragm under two assumptions: hinge joint and rigid joint. To obtain closed-form solutions for the transversal and longitudinal deformations and warping stress of the crane girder, the study employs the Initial Parameter Method and considers the compatibility of shear deformation at joints between the diaphragms and the girder. The theoretical solutions are validated through finite element analysis, which also confirms that the hinge-joint assumption accurately represents the shear angle of the staggered truss diaphragm in girder distortion. Additionally, the study conducts extensive parameter analyses to examine the impact of staggered truss dimensions on distortional stress and deformation. Furthermore, the study compares the distortional warping stresses of crane girders reinforced with staggered truss diaphragms and those reinforced with perforated ones, emphasizing the importance of incorporating stagger truss in diaphragms. Overall, this paper provides a thorough evaluation of the proposed approach's effectiveness in enhancing the distortional frame rigidity of off-rail box girder bridges for cranes. The findings offer valuable insights into the design and reinforcement of diaphragms using staggered truss to enhance the structural performance of crane girders.

• 대한전자공학회논문지
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• 제26권11호
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• pp.1686-1690
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• 1989

Using the anisotropic etching characteristics of N2H4-H2O solutions, Si diaphragm was fabricated for the integrated sensors. The optimal composition and temperature of the etching solution in (100) Si etching process was established to be 50mol% N2H4 in H2O at 105\ulcorner\ulcorner for both higher etch rate (=2.6\ulcorner/min) and better surface quality of etched (100) planes. Based on the above optimal etching condition, the electrochemical etch-stop technique was employed to form n-type Si diaphragm having a thickness of 20\ulcorner and the thickness of diapragm could exactly be controlled to 20\ulcorner\ulcorner.

• 한국전산유체공학회지
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• 제15권3호
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• pp.73-80
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• 2010

In this paper, we present the exact Riemann solver for the compressible liquid-gas two-phase shock tube problems. We hereby consider both isentropic and non-isentropic two-phase flows. The shock tube has a diaphragm in the mid-section which separates the liquid medium on the left and the gas medium on the right. By rupturing the diaphragm, various waves are observed on the phasic field variables such as pressure, density, temperature and void fraction in the form of rarefaction wave, shock wave and material interface (contact discontinuity). Both phases are treated as compressible fluids using the linearized equation of state or the stiffened-gas equation of state. We solve several shock tube problems made of a high/low pressure in the liquid and a low/high pressure in the gas. The wave propagations are well resolved by the exact Riemann solutions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1994-1996
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• 1996

This paper presents the fabrication and testing of a polysilicon piezoresistive accelerometer with p+ silicon diaphragm by simple process such as two step photolithography for the RIE process to form the cantilevers and a deep anisotropic etch process for the complete fabrication of the accelerometer. The fabricated accelerometer consists of a seismic mass and four cantilevers on which polysilicon piezoresistors are formed. The measurement of the output signal from the bridge circuit of the fabricated accelerometer is carried out with the HP 3582A spectrum analyzer. The analysis of the experimental result is showed in terms of the sensitivity and the resonant frequency. At atmospheric condition, the measurement values of the sensitivity and the resonant frequency are $11\;{\mu}V/Vg$ and 475 Hz, respectively.

• Journal of Chest Surgery
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• 제25권12호
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• pp.1461-1464
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• 1992

Cor triatriatum is rare congenital heart disease which is another variant of anomalous pulmonary venous return. It has abnormal fibromuscular diaphragm between true left atrium and accessary chamber which has one or more orifice to the left atrium. In classic form, the patient dies within several months after birth due to pulmonary hypertension inevitably, so it is rarely found in adult. With priopertive echocardiogram and cineangiogram we had two impressions, left atrial cystor cortriatriatum. At operative finding, there was no visible combined anomaly except accessary chamber which received all pulmonary venous return that drained into the left atrium through small calcified orifice. The operation was performed by simple resection of the diaphragm under cardiopulmonary bypass. The postope rative course was uneventful.

• 대한두경부종양학회지
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• 제34권2호
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• pp.17-21
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• 2018

Background/Objectives: Cancers of the abdominal or pelvic organ rarely metastasize to the cervical lymph nodes. Although it indicates distant metastasis, perceivable prolongation of survival or cure may be possible in selected cases. We sought to identify patients with cervical metastasis from cancers below the diaphragm and identify patients who may benefit from aggressive treatment. Materials & Methods: From 2009 to 2017, patients with pathologically confirmed metastatic cervical lymph nodes originating from below the diaphragm were included for analysis. Patient demographics, cancer characteristics, treatment course, and clinical outcomes were analyzed. Results: 208 patients were identified. Left supraclavicular node (Virchow's node) was the most frequently involved. Irrespective of treatment, survival for uterine cervical and ovarian cancers was significantly longer than that of other primaries. Patients with isolated cervical metastasis (oligometastasis) had significantly longer median survival compared to patients with concomitant bone, lung, brain, and mediastinal metastases. Conclusion: Although cervical metastasis from cancers of the abdominal and pelvic organ represent distant metastasis, patients with uterine cervix and ovary primary and oligometastatic lesions may benefit from aggressive treatment. Prudent patient selection and further investigation is warranted.

• Journal of Chest Surgery
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• 제57권5호
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• pp.484-489
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• 2024

Background: Catamenial pneumothorax (CP) is a rare form of spontaneous pneumothorax that is linked to endometriosis; thus, it predominantly manifests in women of reproductive age. Considerable research has explored the potential benefits of postoperative hormone therapy following various surgical interventions. This study was performed to examine the clinical implications of postoperative hormone treatment in patients with CP. Methods: The study included patients who underwent surgical intervention for CP between November 2009 and February 2023. These procedures included wedge resection, diaphragm resection, and total pleural coverage. Recurrence-free survival was analyzed using the Kaplan-Meier log-rank test to assess the impact of hormone therapy. Additionally, Cox proportional hazards analysis was employed to identify risk factors associated with postoperative CP recurrence. Results: The study included 41 patients, with a median age of 38.4 years. Among them, 27 individuals received hormone therapy, 8 of whom experienced recurrence during a median follow-up period of 1 year. Patients who received hormone therapy exhibited a lower rate of recurrence than those who did not; however, the difference was not statistically significant, likely due to the small sample size. Side effects of hormone therapy included depression (6.8%), excessive sweating (3.4%), and headache (3.4%). In the analysis of risk factors for postoperative recurrence, diaphragm resection emerged as a protective factor (hazard ratio, 0.16; 95% confidence interval, 0.03-0.77; p=0.022). Conclusion: Hormone treatment combined with surgery did not significantly impact recurrence in patients with CP. The application of diaphragm resection was the sole factor that displayed significance in preventing CP recurrence.

• 한국소음진동공학회논문집
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• 제26권1호
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• pp.5-12
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• 2016

This paper describes the development process for vibration and acoustic characteristics of a balanced armature speaker. The design parameters were chosen in consideration of the influence of the bending stiffness of balanced armature which is the form of a cantilever structure in the speaker. For study of the performance of the speaker according to the design parameters, in the first step, we analyzed the characteristics of the velocity of the diaphragm to the electrical input. Next step, acoustic characteristics were analyzed by structural-acoustic coupled analysis. And the reliability of the analysis was verified by comparing the result of analysis with test results. Finally, we proposed a design method for implementing an enhanced balanced armature speakers through analysis method.

• Journal of Chest Surgery
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• 제41권2호
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• pp.285-288
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• 2008

이십대에서 삼십대 사이의 여성에서 월경주기와 연관되어 반복적으로 기흉이 발생하는 경우 월경성 기흉과 관련되어 있을 수 있다. 월경성 기흉은 월경의 시작 전후 72시간 이내 반복적으로 발생하는 기흉으로 그 원인과 병태생리가 아직 확립되지 않은 드문 질환이다. 저자들은 2명의 여자 환자에서 발생한 월경성 기흉에 대하여 자궁내막증 및 횡격막 결손을 포함하는 횡격막 부분 절제술을 통한 치료를 경험하였기에 보고하는 바이다.