• 한국전문물리치료학회지
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• 제10권1호
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• pp.129-137
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• 2003

A single subject experimental design (alternating treatment design) was used to compare the effects of only ultrasound and ultrasound combined with stretching of the joint capsule on the ROM increase and pain reduction in patients with frozen shoulder. Two subjects were included in each group. In the only ultrasound treatment sessions, ultrasound was applied at the pain point of the shoulder joint in supine position. In the ultrasound combined with stretching treatment sessions, ultrasound was applied at the pain point of the shoulder joint positioned in external rotation and abduction in sitting position. Only ultrasound treatment and ultrasound combined with stretching treatment were alternately performed on each patient. Pain and disability was measured by shoulder pain and disability index (SPADI), and range of motion (ROM) was measured by scratch test. The results of this study showed that ultrasound combined with stretching treatment were more effective than only ultrasound treatment in ROM increase and pain reduction. However, disability score was not significantly different.

• 대한기계학회논문집B
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• 제25권5호
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• pp.741-749
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• 2001

An inhomogeneous hyperbolic electric field is established among two-dimensional quadrupole electrodes to which an ac voltage is applied. Conditions under which charged particles are focused into a narrow axis region of the plug laminar flow are discussed. The aerodynamic forces influence the behavior of the charged particles in the quadrupole electric field. We derived the dimensionless equations of motion of a charged particle in the alternating quadrupole electric field, and discussed particle trajectories and focusing performance in terms of two dimensionless parameters, which are functions of particle size, operating pressure, and the amplitude and frequency of applied AC voltage, with the results of numerical simulations and experiments.

• 정보저장시스템학회논문집
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• 제3권2호
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• pp.66-72
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• 2007

Surface finishing using magnetorheological (MR) fluid is useful to finish small but not too small workpieces such as those in a few millimeter scale. However, due to the high surface hardness, this finishing process does not seem to be suit for applying to a hard disk slider. In this work, a preliminary study is performed on the finishing of the hard disk slider surface with a mixture of an MR fluid and diamond powder. During a wheel type MR finishing process, centrifugal force is found to be a major factor to cause a reduction in material remove rate (MRR), which is supported by a theoretical model. To facilitate this founding, the rotational speed of tool is confined to 500rpm while a rectilinear alternating motion with the mean speed, which is equivalent to the rotational speed, is additionally applied to the workpieces. As a consequence, MRR of about 2 times of the sole rotational case is obtained. This paper shows that MR finishing process can be used to polish a hard material in millimeter scale efficiently by controlling the speeds of the tool and the workpiece.

• 대기
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• 제23권3호
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• pp.293-305
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• 2013

대류가 유도하는 중규모 흐름에 미치는 비정역학 효과를 조사하기 위하여 기존의 무차원화된 정역학 모형을 바탕으로 무차원화된 비정역학 모형을 개발하였다. 모형을 검증하기 위하여 정역학 방정식 계의 해석해와 비정역학성이 아주 작은 경우의 수치 실험 결과를 비교하였고, 두 결과가 거의 같음을 확인하였다. 무차원화된 비정역학 모형을 이용하여 선형 계와 비선형 계에서 대류가 유도하는 중규모 흐름에 미치는 비정역학 효과를 조사하였다. 선형 계와 비선형 계 모두에서 비정역학성 인자가 작은 경우 열원 꼭대기 위에서 연직 방향으로, 비정역학성 인자가 상대적으로 큰 경우 주 상승 기류의 풍하측에서 수평 방향으로 상승 운동과 하강 운동이 교대하는 파동 형태의 섭동장이 나타났다. 풍하측에서 나타나는 상승 운동과 하강 운동을 분석하기 위하여 선형, 정상 상태, 비점성 흐름에 대한 Taylor-Goldstein 방정식을 구하였다. 주 상승기류의 풍하측에서 교대로 나타나는 상승 하강 기류세포는 전파파의 수평 방향 전파 성분과 에바네센트파, 즉 비정역학성 인자에 의해 결정되는 임계 파장보다 파장이 짧아 연직 방향으로 전파되지 못하고 수평 방향으로만 전파되는 중력파의 중첩으로 설명할 수 있다. 선형 계에 대한 수치 실험 결과에서 나타난 상승 하강 기류 세포의 수평 방향 길이는 선형 계에 대한 방정식에서 얻은 에바네센트 파의 임계 파장 길이의 절반과 일치하였으나, 약한 비선형 계에 대한 수치 실험 결과에서 나타난 상승 하강 기류 세포의 수평 방향 길이는 선형 계에 대한 방정식에서 얻은 에바네센트 파의 임계 파장 길이의 절반보다 다소 길었다. 주 상승 기류 지역 내에서 최대 상승 기류의 위치는 비선형성과 비정역학성 정도에 따라 다르게 나타났다.

• 한국항만학회지
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• 제13권1호
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• pp.155-166
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• 1999

The construction of the coastal structures and reclamation work causes the circulation reduced in the semi-closed inner water area and the unbalanced sediment budget of beach results in an alteration of beach topography. Among the various fluid motions in the nearshore zone water particle motion due to wave and wave-induced currents are the most responsible for sediment movement. Therefore it is needed to predict the effect of the environmental change because of development and so the prediction of wave transformation dose. The purpose of this study is to introduce the relation between waves wave-induced currents and sediment movement. In this study we will show numerical method using energy conservation equation involving reflection diffraction and reflection and the surfzone energy dissipation term due to wave breaking is included in the basic equation. For the wave-induced current the momentum equation was combined with radiation stresses lateral mixing and friction Various information is required in the prediction of wave-induced current depending on the prediction tool. We can predict changes in wave-induced current from the distribution of wave especially near the wave breaking zone. To evaluate these quantities we have to know the local condition of waves mean sea level and so on. The results from the wave field and wave-induced current field deformation models are used as input data of the sediment transport and bottom change model. Numerical model were established by a finite difference method then were applied to the development plan of the eastern Pusan coastal zone Yeonhwa-ri and Daebyun fishing port. We represented the result with 2-D graphics and made comparison between before and after development.

• Journal of Acupuncture Research
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• 제33권2호
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• pp.77-87
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• 2016

Objectives : This is a pilot study for a large randomized controlled trial to investigate the efficacy and safety of a newly developed contrast therapy device-- alternating topical heat and cold -- for patients with chronic low back pain. The main objective of this study is to confirm the feasibility of the study design. Methods : The design was a randomized, 2-arm, parallel-group, single-blind, placebo controlled trial. Patients in each group received real or sham contrast therapy in an acupuncture point 10 times over four weeks. The primary outcome measure was pain intensity on a 100-mm visual analogue scale (VAS). The secondary outcomes were back-related dysfunction based on the Oswestry Disability Index (ODI), the Roland-Morris disability questionnaire (RMDQ), and range of motion of lumbar spine based on the modified Schober test (mSchober test), Finger-to-Floor distance (FTF distance), and Finger-to-Thigh distraction (FTT distraction). Results : A total of 30 subjects with chronic low back pain were randomly assigned to a contrast therapy group (n＝15) or a sham group (n＝15). A repeated-measures analysis of variance showed statistically significant group time interaction for VAS, RMDQ, mSchober test and FTF distance (p<0.05). The treatment group showed significant improvement in pain intensity and functional disability as compared to the sham group. Conclusion : Contrast therapy may be an effective and safe treatment for chronic low back pain.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.551-555
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• 2010

Electrowetting is a versatile tool to handle tiny droplets and forms a backbone of digital microfluidics. Numerical analysis is necessary to fully understand the dynamics of electrowetting, especially in designing electrowetting-based devices, such as liquid lenses and reflective displays. We developed a numerical method to analyze the general contact-line problems, incorporating dynamic contact angle models. The method is based on the conservative level set method to capture the interface of two fluids without loss of mass. We applied the method to the analysis of spreading process of a sessile droplet for step input voltages and oscillation of the droplet for alternating input voltages in electrowetting. The result was compared with experimental data. It is shown that contact line friction significantly affects the contact line motion and the oscillation amplitude. The pinning process of contact line was well represented by including the hysteresis effect in the contact angle models. In level set method, in the mean time, material properties are made to change smoothly across an interface of two materials with different properties by introducing an interpolation or smoothing scheme. So far, the weighted arithmetic mean (WAM) method has been exclusively adopted in level set method, without complete assessment for its validity. We viscosity, thermal conductivity, electrical conductivity, and permittivity, can be an alternative. I.e., the WHM gives more accurate results than the WAM method in certain circumstances. The interpolation scheme should be selected considering various characteristics including type of property, ratio of property of two fluids, geometry of interface, and so on.

• 대한한방내과학회지
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• 제44권1호
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• pp.1-11
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• 2023

Objective: There are currently no disease-modifying medications or definite long-term sustainable interventions for patients with Parkinson's disease (PD), indicating an unmet treatment need. Our goal was to create a long-term sustainable intervention for PD patients that can be used in Korean medicine clinics. Methods: The Meridian Activation Remedy System (MARS) was created to stimulate a patient's 12 meridians and sinew channels using a combination of acupoint stimulation and exercise. The acupoints and motions used in MARS were selected through literature studies and expert advice. The methodologies were refined using observational and case studies. With slow and fast movements, the MARS intervention was intended to activate both slow- and fast-twitch muscle fibers. Intradermal acupuncture and motion that shift the center of gravity were employed to enhance the patient's balance and proprioception. In addition, the intervention included alternating movement exercises to address the complex cognitive decline commonly occurring in PD patients. Results: The following acupoints were chosen for the MARS intervention: bilateral Hegu (LI4), Houxi (SI3), Waiguan (TE5), Neiguan (PC6), Zhongchong (PC9), Yuji (LU10), Zusanli (ST36), Yanglingquan (GB34), Taichong (LR3), Kunlun (BL60), and Taixi (KI3). We also developed actions that can stimulate the body's 12 meridians. Conclusion: We developed the MARS intervention, which combines acupuncture and exercise, to address the unmet therapeutic needs of PD patients. We hope that with additional research, the MARS intervention can be set as an effective therapeutic program for PD patients.

• 한국자기학회지
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• 제25권3호
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• pp.83-86
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• 2015

무기체계가 첨단, 고도화되면서 탄약을 정밀 제어하여 목표를 타격하기 위하여 공중폭발탄(ABM)이 개발되어 전장에서 운용되고 있다. 이러한 공중폭발탄의 시한정밀도를 향상시키기 위하여 총구를 이탈하는 탄의 속도를 측정하여 표적까지의 정확한 비행시간을 계산한 후 탄에 입력하여야 한다. 본 연구에서는 K4 기관총의 소염기 부분에 탄을 감지할 수 있는 장치를 도입하였다. 탄약의 주요 금속 부품은 신관 부분의 알루미늄과 파편 효과를 발휘하는 탄체의 철 부분, 총열의 강선부를 통과할 때 직진운동을 회전운동으로 전환시키는 회전탄대의 구리로 구성되어 있는데 알루미늄 부분을 탐지하기 위하여 와전류 탐촉자의 원리를 도입하였다. 탄이 총구를 벗어나는 수십 us 동안 탄속을 측정하기 위하여 U 자형의 MnZn Ferrite 코어에 코일을 권선하여 200 kHz의 교류 전류를 인가하여 탄의 총구 이탈 속도를 측정하였으며, 도플러 레이더와 병행 계측한 결과 ${\pm}1%$ 이내에서 잘 일치하였다.

• 한국전자통신학회논문지
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• 제12권2호
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• pp.391-400
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• 2017

본 연구의 목적은 스마트 기기를 활용한 구강안면 훈련 영상 프로그램이 마비말장애가 있는 급성 뇌졸중 환자의 구강 구조 및 기능과 조음교대운동속도에 미치는 효과를 알고자 하였다. 본 연구는 마비말장애가 있는 급성 뇌졸중 환자 14명을 대상으로 하였다. 연구에 참가한 모든 대상자들은 실험군과 대조군으로 7명씩 무작위 할당되었다. 두 그룹의 대상자들은 4주 동안 모두 동일하게 보편적인 재활치료를 받았다. 실험군은 스마트 기기를을 활용한 구강안면 훈련 영상 프로그램을 보호자의 감독 하에 추가적으로 30분씩 더 수행하였다. 구강 구조와 기능을 측정하기 위하여 조음기관 구조 및 기능선별검사의 하위항목인 구강 구조와 기능을 평가하였다. 조음교대운동속도를 측정하기 위하여 교대운동속도와 연속운동속도를 평가하였다. 연구 결과, 그룹 내 비교에서 실험군과 대조군은 구강 구조 및 기능, 교대운동속도, 연속운동속도에서 유의한 향상을 보였다(p<.05). 두 그룹 간 변화량 비교에서 실험군은 대조군보다 구강기능과 교대운동속도의 /퍼/와 /터/에서 유의한 향상을 보였다(p<.05). 스마트 기기를 활용한 구강안면 훈련 영상 프로그램은 마비말장애가 있는 급성 뇌졸중 환자의 구강 기능과 조음기관 기능에 긍정적인 효과를 기대할 수 있는 중재방법으로 사료된다.