• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.182-183
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• 2008

In this study, rotor dynamic analysis have been conducted using three-dimensional solid model. Analysis object has smaller size and higher speed than any general CNC spindle. It is important to consider the real supporting conditions and external forces for whirl behavior analysis. As a results, the bearing stiffness is higher, whirl motion is less than before.

• 한국방재학회 논문집
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• 제1권1호
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• pp.81-90
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• 2001

2경간 연속 철도교의 종방향 거동에 영향을 미치는 여러 인자들에 대해서 연구하였다. 그 인자들로는 교각 강성의 크기, 교각의 높이, 교각기초의 크기와 교각받침의 강성을 변화시켜 그에 따른 변화양상을 살펴보았다. 그 결과 고정단 교각에서의 여러 인자들의 변화에 따른 종방향 거동의 변화가 가동단 교각에서의 변화에 따른 영향보다 크다는 사실을 확인할 수 있었다. 또한, 받침강성을 변화시켜서 종방향 거동을 제어하는 것이 다른 인자들을 변화시키는 것보다 더 경제적이라 할 수 있다.

• 한국소음진동공학회논문집
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• 제13권10호
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• pp.785-790
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• 2003

This paper presents an approach to optimally design the air-hearing surface (ABS) of the optical flying head for near-field recording technology (NFR) NFR is an optical recording technology using very small beam spot size by overcoming the limit of beam diffraction. One of the most important problems in NFR Is a head disk interface (HDI) issue over the recording band during the operation. A multi-criteria optimization problem is formulated to enhance the flying performances over the entire recording band during the steady state. The optimal solution of the slider, whose target flying height is 50 nm, is automatically obtained. The flying height during the steady state operation becomes closer to the target values than those for the Initial one. The pitch and roll angles are also kept within suitable ranges over the recording band. Especially. all of the all-hearing stiffness are drastically increased by the optimized geometry of the air hearing surface.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.1021-1026
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• 2000

The thermal characteristics of high-speed air spindle system with built-in motor are studied. Experiment and finite element method analysis obtain temperature rise and temperature distribution of housing. For the analysis three-dimensional model is built and temperature rise and distribution in thermal steady state are computed for each rotational frequency. Generally. It is said that the heat generation of air bearing is negligible. But it is certain that the heat generation of air bearing can not be negligible especially in high-speed conditions Frequency response test for air spindle system is executed. In case that the heat generation of air spindle system is high, natural frequency of the system becomes lower when it reaches thermal steady-state and it means that the stiffness of air hearing becomes smaller due to the change of bearing clearance. It is shown that the temperature rise of all spindle system causes thermal expansion md induces the variation of hearing clearance. In consequence the st illness of air bearing becomes smaller.

• 한국소음진동공학회논문집
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• 제12권2호
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• pp.116-123
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• 2002

Applying a general coupled lateral and torsional vibration finite element model of gear pair element, this paper intends to look into in detail the coupled lateral and torsional vibration characteristics of a turbo-chiller rotor bearing system, having a bull-pinion speed increasing gear. Investigations have been carried out systematically by comparing the uncoupled and coupled natural frequencies and their mode shapes upon varying the gear mesh stiffness with considerations on rotating speeds, and also by comparing the strain energies of lateral and torsional vibration modes. Results hale shown that some modes may hale the coupled lateral and torsional mode characteristics as the gear mesh stiffness Increases over a certain value, and moreover that their associated dominant modes may be different from their initial modes, j.e., a certain dominant mode may change from an initial torsional one to a lateral one or from an initial lateral one to a torsional one.

• 대한간호학회지
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• 제26권4호
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• pp.903-916
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• 1996

The purpose of this study was to discover practical health problems which hemodialysis clients experienced so as to present basic data for development of a health assessment tool. The research subjects were 70 clients receiving hemodialysis in Seoul and Inchon from Mar. 1996 to Sep. 1996. Data were collected by researcher's informal indepth interview and nurses' open ended question. Content analysis was applied to collect similar contents and common experiences in order to derivate concepts and categories for better understanding of hemodialysis clients' experiences. As a result, 9 categories derivated to identify the health problems of clients receiving hemodialysis were as follows : 1) They experienced 'the decreased digestive function' which contained the changed appetite, nausea, vomiting, constipation and diarrhea. 2) They experienced 'the decreased respiratory and circulatory function' which contained dyspnea, changed blood pressure, tingling sensation and the fear of aggrevated vascular condition. 3) They experienced 'the aggrevated oral condition' which contained dry mouth and destruction of teeth and their soft tissue. 4) They experienced 'the decreased sensory function' which contained visual disturbances, sensation difficulty, and hearing loss. 5) They experienced 'the aggrevated skin condition' which contained dark brown skin color, dry skin (and hyperpigmentatic freckle, seborrheric keratosis, scale), itching sense, and alopethia. 6) They experienced 'the decreased urinary reproductive function' which contained anuria or oliguria, dysmenorrhea, sterility and decreased libido. 7) They experienced 'the restricted activity' which contained decreased activity, muscle cramp and stiffness of joint. 8) They experienced 'the changed mental status' which contained memory disturbance, decreased cognition, disorientation, neurosis and psychosis. 9) They experienced 'the aggrevated general condition' which contained kyphosis, weight loss, fatigue, sleep disturbance, bleeding tendency, inflammation, generalized edema and foul oder of uremia.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.523-530
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• 2006

A rotordynamic analysis was performed with a dry vacuum pump, which is a major equipment in modern semiconductor and LCD manufacturing processes. The system is composed of screw rotors, lobes picking air, helical gears, driving motor, and support rolling element hearings of rotors and motor. The driving motor-screw rotor system has a rated speed of 6,300rpm, and was modeled utilizing a rotordynamic FE method for analysis, which was verified through the results of its 3-D finite element model. As loadings on the bearings due to the gear action were significant in the system considered, each resultant bearing load was calculated determinately and indeterminately by considering the generalized forces of the gear action as veil as the rotor itself. Each resultant hearing loading was used in calculating each stiffness of rolling element bearings. Design goals are to achieve wide separation margins of critical speeds and favorable unbalance responses of the rotor in the operating range. Then, a complex rotordynamic analysis of the system was carried out to evaluate its forward synchronous critical speeds, whirl natural frequencies and mode shapes, and unbalance responses under various unbalance locations. Results show that the entire system is well designed in the operating range. In addition, the procedure of rotordynamic analysis for dry vacuum pump rotor-bearing system was proposed and established.

• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4567-4570
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• 2013

Background: Nasopharyngeal carcinoma (NPC) is the commonest radiocurable cancer in Malaysia. This study aimed to determine the treatment outcomes and late effects of radiotherapy for NPC patients treated in University Malaya Medical Centre (UMMC). Materials and Methods: All newly diagnosed patients with NPC referred for treatment to the Oncology unit at UMMC from 2004-2008 were retrospectively analyzed. Treatment outcomes were 5 years overall survival (OS), disease free survival (DFS), cause-specific survival (CSS), locoregional control (LRC) and radiotherapy-related late effects. The Kaplan-Meier method was used for survival analysis and differences in survival according to AJCC stage was compared using the log-rank test. Results: A total of 176 patients with newly diagnosed NPC were treated in UMMC during this period. Late presentation was common, with 33.5% presenting with T3-4 disease, 84.7% with N1-3 disease and 75.6% with AJCC stage 3-4 disease. Radical RT was given to 162 patients with 22.7% having RT alone and 69.3% having CCRT. The stipulated OTT was 7 weeks and 72.2% managed to complete their RT within this time period. Neoadjuvant chemotherapy was given to 14.8% while adjuvant chemotherapy was administered to 16.5%. The 5 years OS was 51.6% with a median follow up of 58 months. The 5 years OS according to stage were 81.8% for stage I, 77.9% for stage II, 47.4% for stage III and 25.9% for stage IV. The 5 years overall CSS, DFS and LRC were 54.4%, 48.4% and 70.6%, respectively. RT related late effects were documented in 80.2%. The commonest was xerostomia (66.7%). Other documented late effects were hearing deficit (17.3%), visual deficit (3.1%), neck stiffness (3.1%), dysphagia (3.4%), cranial nerve palsy (2.5%), pneumonitis (0.6%) and hypothyroidism (1.2%). Conclusions: The 5 years OS and LRC in this study are low compared to the latest studies especially those utilizing IMRT. Implementation of IMRT for NPC treatment should be strongly encouraged.

• Pediatric Infection and Vaccine
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• 제24권1호
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• pp.65-70
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• 2017

거대세포바이러스 감염은 선천감염의 가장 흔한 원인 중의 하나이다. 본 증례는 쌍생아에서 다른 임상 양상을 보인 선천 거대세포바이러스 감염 증례에 대한 국내 첫 보고이다. 31세 초산부가 쌍생아(2 융모막, 2 양막)를 임신하였다. 임신 34주 산전 초음파에서 한쪽 태아의 크기가 작고 양측 뇌실 확장증이 발견되었으며 임신 37주경에 제왕절개로 분만하였다. 첫 번째 신생아는 남자로 출생 체중 2,410 g, 아프가 점수 8/9점으로 출생하였으며 두 번째 신생아는 여자로 출생 체중 1,380 g, 아프가점수 5/8점으로 출생하였다. 두 번째 신생아는 자궁 내 성장지연, 소두증, 소하악증, 사지 관절의 강직을 보였다. 불일치 쌍생아에 대한 원인을 찾기 위한 검사를 진행하였으며 두 번째 신생아의 혈액검사에서 거대세포바이러스 immunoglobulin M이 양성반응을 보였으며 소변과, 혈액, 뇌척수액에서 거대세포바이러스 중합효소연쇄반응이 양성소견을 보였다. 반면에 정상으로 출생한 남아의 거대세포바이러스에 대한 검사는 모두 음성이었다. 감염된 환자의 안과적 검진에서 거대세포바이러스 망막염이 관찰되었고, 후에 실시한 청력검사에서 양측의 감음 난청이 확인되었다. 환자는 ganciclovir 치료를 받았으며 현재 여아는 심한 발달지연이 있으며 침대에서 누워서 생활하는 중이다. 이와 같이 쌍생아에서의 선천 거대세포 바이러스 감염증이 한 명에게만 발생하는 경우의 원인은 현재까지 명확하지 않다. 하지만 이 증례를 통하여 심한 불일치 쌍생아의 경우에 선천 거대세포바이러스 감염의 가능성을 고려해 보아야 한다.