• 정보학연구
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• 제8권1호
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• pp.43-50
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• 2005

Quantitative analysis for distribution of penetrating ultrasound in vivo is very important to determine the treatment region and method. In this paper, we constructed a simplified 2-D femoral region model that consists of skin-fat-muscle-bone layered system, and simulated the pressure distribution in the model in case of applying ultrasound using Finite Element Method(FEM). The ultrasound used in the simulation was assumed to be pulse wave and the pressure distribution was analyzed during only one period of pulse wave. In order to find the penetration depth, amplitude of pressure and sphere that ultrasound reaches in the model, we performed the simulation with varying the applied frequency, transducer size and amplitude of transducer's output. The result showed that applied frequency is inversely proportional to the penetration depth and amplitude of pressure but the amplitude of transducer's output is proportional to the amplitude of pressure in the model. Also, the sphere that ultrasound reaches was widened and the amplitude of pressure became larger as the transducer size became larger. This results were similar to that obtained from the previous model consisting of fat-muscle-bone layered system, but we observed that the pressure of ultrasound is decreased due to the decrements of pressure by the absorption coefficient of skin and the interference that depends on the reflection of ultrasound caused by the difference of acoustic impedance of skin and fat. Finally, we can infer that the model proposed in this study is closer to the realistic model than the previous ones. It shows that the results obtained from this study can be useful in designing the ultrasound treatment instrument or in setting up the treatment plan.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.146-149
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• 2003

To control the position, velocity and torque of the ultrasonic motor, a great variety of method are proposed such as the amplitude, phase difference, frequency and so on. In the case of phase difference method, it has some advantages: it can control the direction and velocity of rotation only adjusting the phase difference and it has wide control-band. During the USM driving on adjusting phase difference, its characteristic was transformed by the change of resonance-frequency of stator, which means that the resonance frequency is different according to the phase difference. Consequently, we need to set up the most suitable driving frequency according to each phase difference.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 1호
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• pp.189-197
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• 1999

To investigate internal waves (IW) effect on acoustic wave propagation, m analysis is conducted on mode travel time and model simulation. Based on the thermistor string data, it can be shown that the thermocline depth variation may cause travel time difference as much as 4-10 ms between mode 1 and 2 over range 10 km. This travel time difference causes interference among modes and thus fluctuation from range-independent stratified ocean structure. In real situations, however, there exist additionally spatial variation of IW. Model simulation with all modes and simple IW shows clear responses of acoustic signals to IW, amplitude and phase fluctuation.

• 대한물리의학회지
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• 제13권2호
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• pp.129-135
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• 2018

PURPOSE: The imbalance of pretibial muscles can be a factor contributing to the development of pes planus. However, no study has yet compared the muscle activity of the tibials anterior (TA) to that of the extensor digitorum longus (EDL). The purpose of this study was to determine whether there are differences in the electromyographic (EMG) TA and EDL amplitude indexes (AIs) between normal and pes planus feet. METHODS: A total of 14 subjects with normal feet and 15 subjects with bilateral pes planus participated in this study. TA and EDL muscle activities were measured using a wireless EMG system and the angles of ankle dorsiflexion and eversion of the subtalar joint were measured using a universal goniometer during active ankle dorsiflexion in the prone position. AI was calculated as follows: $\text{amplitude_{TA}-amplitude_{EDL}/(amplitude_{TA}+amplitude_{EDL})}/2{\times}100$. RESULTS: The AIs of the TA and EDL were significantly lower in pes planus feet than in normal feet (p<.05). The angle of subtalar eversion was significantly greater in pes planus feet than in normal feet during active ankle dorsiflexon (p<.05). However, there was no significant difference in the angle of ankle dorsiflexion between normal feet and pes planus feet (p>.05). CONCLUSION: This study showed that TA muscle activation was lower in pes planus feet than in normal feet, resulting from greater eversion range of motion during active ankle dorsiflexion. We suggest that the imbalance of ankle dorsiflexors must be considered in pes planus management.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2008년도 공동학술대회
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• pp.107-112
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• 2008

동해가스전과 같이 해저면 심부에 위치한 저류층의 경우 CMP 단면도 상에서 AVO 반응을 관찰하기가 어려운 경우가 종종 발생한다. 이렇게 심부저류층인 경우 고결성이 증가하기 때문에 매질의 공극유체가 가스로 치환되더라도 매질의 P파 속도가 크게 감소하지 않으며 이로 인해 AVO 반응 확인이 어렵다. 본 연구에서는 상.하부층의 포아송비를 달리하면서 포아송비의 차이가 작아질수록 입사각에 따른 반사진폭의 변화량이 작아져 AVO 반응이 미미해짐을 관찰하였다. 이 결과를 토대로 동해가스전의 AVO 반응의 한계점을 고찰하기 위해서 탄성파 자료와 물리검층 자료를 이용하여 고래 V 구조를 모사한 속도모델을 만들고 합성탄성파 탐사자료를 생성하였다. 매질의 성질을 이용하여 이론적으로 계산한 AVO 반응과 실제 합성탄성파 자료를 처리하여 얻은 AVO 반응을 비교한 결과, 상.하부층의 포아송비의 차이가 작을 경우 입사각에 따른 반사진폭 변화가 매우 작으며 잡음이나 전처리 과정 중에서 발생하는 진폭 왜곡에 의해 AVO 반응 특성이 가려짐을 확인할 수 있었다. 이러한 심부저류층의 AVO 분석의 한계점을 극복하기 위해서는 자료취득 단계부터 정확한 반사파 진폭을 획득해야 하며 자료처리 과정에서도 반사파 진폭을 보존할 수 있는 기술이 필요하다.

• The Journal of Korean Physical Therapy
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• 제17권3호
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• pp.329-338
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• 2005

The determination of peripheral nerve conduction velocity is an important part to electrodiagnosis. Its value as neurophysiologic investigative procedure has been known for many years but normal value of digital nerve was not reported in Korea. To evaluate of digital nerve conduction velocity of median nerve for obtain clinically useful reference value and compare difference in each fingers. 71 normal volunteers(age, 19-65 years; 142 hands) examined who has no history of peripheral neuropathy, diabetic mellitus, chronic renal failure, endocrine disorders, anti-cancer medicine, anti-tubercle medicine, alcoholism, trauma, radiculopathy. Nicolet Viking II was use for detected conduction velocity and amplitude of digital nerves in median nerve. Data analysis was performed using SPSS. Descriptive analysis was used for obtain mean and standard deviation, ANOVA was used to compare each fingers and independent t-test was used to compare between Rt and Lt side also compare between different in genders. Conduction velocity of the right thumb was 49.77m/sec, index finger was 56.80m/sec, middle finger was 56.15m/sec and ring finger was 53.38m/sec. The left thumb was 50.48m/sec, index finger was 56.76m/sec, middle finger was 55.99m/sec and ring finger was 53.23m/sec. Amplitude of the right thumb was $64.30{\mu}V$, index finger was $73.95{\mu}V$, middle finger was $77.97{\mu}V$ and ring finger was $43.92{\mu}V$. The left thumb was $74.21{\mu}V$, index finger was $85.72{\mu}V$, middle finger was $88.06{\mu}V$ and ring finger was $47.28{\mu}V$. There were significantly difference between thumb, index, middle and ring fingers(p<.01) but there were no statistically difference between conduction velocity and amplitude of index and middle fingers(p>.01). The conduction velocity of index finger are faster than other fingers and amplitude of middle finger are greater than other fingers. The present results revealed that electodiagnosis can easily perform in index and middle finger for digital nerve of median nerve study.

• 대한정형도수물리치료학회지
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• 제11권2호
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• pp.13-18
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• 2005

The ulnar nerve extends down the arm, across the elbow, and into the hand. It provides sensation to the little and ring fingers and activates many of the small muscles in the hand. The determination of peripheral nerve conduction velocity is an important part of ulnar nerve evaluation. The electrodiagnostic value as neurophysiologic investigative procedure has been known for many years but normal value of digital nerve was not reported in Korea. The purpose of this investigation was to measure the digital nerve conduction velocity of ulnar nerve for obtain clinically useful reference value and compare difference in each fingers and then compare with the other countries. 71 normal Korean volunteers (age, 19-65 years; 142 hands) examined who has no history of peripheral neuropathy, diabetic mellitus, chronic renal failure, endocrine disorders, anti-cancer medicine, anti-tubercle medicine, alcoholism, trauma, radiculopathy. Nicolet Viking II (EMG machine) was use for detected conduction velocity and amplitude of digital nerves in ulnar nerve. Data analysis was performed using SPSS. Descriptive analysis was used for obtain mean and standard deviation and independent t-test was used to compare with ring and little finger. Conduction velocity of the right ring finger was 57.44m/sec and little finger was 55.32msec. The left ring finger was 55.55msec and little finger was 54.11msec. Amplitude of the right ring finger was $30.28{\mu}V$ and little finger was $48.36{\mu}V$. The left ring finger was $30.67{\mu}V$ and little finger was $52.76{\mu}V$. There were significantly difference between ring and little in amplitude (p<.05) but there were no statistically difference between conduction velocity of ring and little finger (p>.05). The amplitude of little finger are greater than ring finger. The present results revealed that electodiagnosis can easily perform in little finger for digital nerve of ulnar nerve study.

• 대한치과교정학회지
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• 제22권1호
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• pp.253-271
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• 1992

The purpose of this study was to investigate the difference of EMG activity of the Orbicularis oris and Mentalis muscle between normal occlusion and class III malocclusion group during various lip position and to find out whether any correlations exist between the muscular activity and craniofacial morphology. In this study, 50 subjects with a mean age of 22.9 Years (range 20.0-26.0) were investigated (25 subjects were normal occlusion, and 25 subjects were class III malocclusion). EMG data were recorded from the Orbicularis oris and Mentalis muscle during rest lip posture, lip position at maximum biting, lip position at maximum sealing effort, lip position at chewing, swallowing and phonation with the Medelec MS-25 electromyographic machine. Lateral cephalometric radiographs was taken with the mandible in intercuspal position on all subjects. All data were recorded and statistically processed. The findings of this study can be summerized as follows: 1. In normal occlusion, the maximal mean amplitude of upper lip during the lip position at chewing was lower than that of lower lip and mentalis muscle. But the maximal mean amplitude of orbicularis oris and mentalis muscle during the other lip position was not statistically different. 2. In Class III malocclusion, the maximal mean amplitude of upper lip during the lip position at chewing, swallowing and phonation was lower than that of lower lip and mentalis muscle. But the maximal mean amplitude of orbicularis oris and mentalis muscle during the other lip position was not statistically different. 3. Compare to normal occlusion, the Class III malocclusion was showed low maximal mean amplitude of upper lip during rest lip posture and the lip position at swallowing of saliva, and showed great maximal mean amplitude of lower lip and meantalis muscle during the lip position at chewing and phonation. 4. In normal occlusion, the maximal mean amplitude of upper lip during various lip position was not correlated with the length and thickness of upper lip, but the maximal mean amplitude of lower lip during the lip position at chewing and swallowing was positively correlated with the thickness of lower lip. 5. In Class III malocclusion, the maximal mean amplitude of upper lip during rest lip posture was negatively correlated with the thickness of upper lip, and the maximal mean amplitude of lower lip and mentalis muscle during the lip position at chewing and swallowing was positively correlated with the thickness of lower lip and mentalis muscle. But the maximal mean amplitude of orbicularis oris and mentalis muscle during the other lip position was not correlated with the cephalometric measurements of soft tissue. 6. The correlation between the maximal mean amplitude of orbicularis oris and mentalis muscle and cephalometric measurements of incisors was not nearly present. 7. In normal occlusion, the maximal mean amplitude of lower lip and mentalis muscle during the lip position at maximum biting was negatively correlated with the angle between palatal plane and mandibular plane. In Class III malocclusion, the maximal mean amplitude of upper lip, lower lip and mentalis muscle during function was negatively correlated with the length of maxilla, the maximal mean amplitude of upper lip and lower lip during function was negatively correlated with the SNA and SNPo, and the maximal mean amplitude of lower lip during the lip position at chewing was negatively correlated with the ANB.

• 한국음향학회지
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• 제18권3호
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• pp.55-61
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• 1999

본 연구에서는 쿼드러춰 방식의 초음파현미경을 구성하고 미세한 높이변화를 갖는 표면결함에 대한 진폭영상과 위상영상을 복원하여 상대적인 영상 강도의 변화와 영상의 질을 비교 분석하였다. 본 실험에서는 중심주파수가 3㎒인 focused 변환기를 사용하여 초음파현미경을 구성하고 알루미늄 재료를 선택하여 하나는 직경이 2㎜이고 깊이가 100㎛인 원형결함을 갖도록 하였고 다른 하나는 직경이 4㎜이고 깊이가 5㎜인 원형결함을 갖도록 시편을 제작하였으며 이들에 대한 진폭과 위상영상을 복원하였다. 결함 깊이가 100㎛인 원형결함이 존재하는 시편에 대한 라인 스캔(line scan) 결과 상대적인 영상강도의 진폭 변동율은 7%로 미약한 반면에 위상 변동율은 89%로 커다란 변화를 나타내므로 결함에 대해서 위상영상이 우수한 콘트라스트를 보였다. 이에 비하여 결함의 깊이가 5㎜인 시편에 대해서 진폭영상은 위상영상에 비하여 우수한 콘트라스트를 보이므로서 결함 깊이가 한 파장을 기준으로하여 위상영상과 진폭영상은 큰 차이를 나타내었다. 따라서 쿼드러춰 검출방식의 초음파현미경은 진폭만을 검출하는 포락선 검출기에 비해 한 파장보다 작은 높이변화를 갖는 결함의 탐상시 위상영상을 진폭영상의 상호보완적인 관계로 사용하므로서 결함의 미세 높이 변동을 효율적으로 평가 할 수 있다.

• 대한임상검사과학회지
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• 제52권3호
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• pp.194-201
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• 2020

잠복기와 전위는 MMN의 측정 매개변수이다. 이 매개변수의 수치는 자극방안에 따라 민감하게 변한다. MMN 검사를 위해 주파수 차이를 자극변이로 이용하는 자극방안이 잘 알려져 있다. 이 자극방안을 이용하여 건강하고 젊은 성인에서 MMN 검사를 하고 매개변수의 참고치를 구하는 것이 본 연구의 목적이다. 저자들은 10명의 정상성인을 모집하였다. 이들의 연령은 평균 25.5세이고, 3명은 여성 7명은 남성이었다. MMN 검사를 위한 청각 자극방안에서 표준소리의 주파수는 1,000 Hz, 변이소리의 주파수는 1,032 Hz였다. MMN의 평균잠복기와 평균전위가 Fz에서 202 ms 와 1.88 ㎶, Cz에서 207 ms와 1.46 ㎶, C3에서 212 ms와 1.10 ㎶, 그리고 C4에서 214 ms와 1.45 ㎶였다. MMN의 잠복기와 전위사이에 상관성은 관찰되지 않았다. 본 연구는 적용하기 쉬운 표준자극방안으로 검사한 MMN의 잠복기와 전위의 참고치를 제시하였다. 이 정보는 임상과 기초연구에서 MMN의 유용성을 높일 것이다.