• 대한정형도수물리치료학회지
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• 제13권2호
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• pp.1-11
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• 2007

Purpose: The purpose of this study was to determine the effect of continuous wave ultrasound and pulsed wave ultrasound that influence changes in pain and range of motion when applied to patients with temporomandibular joint disability. Methods: The subjects of the study were 40 selected patients who had been diagnosed with temporomandibular joint movement restriction and had endured pain for more than two weeks. These patients had visited K orthopedic surgery in Deagu measured from October 1, 2004 to March 31, 2005. The subjects were divided into two groups with 20 patients each. The one group was applied to continuous wave ultrasound and the other group was applied to pulsed wave ultrasound at a dosage of 1.5 W/$cm^2$ for a duration of 5 minutes and eight times for two weeks. The pain perception degree were measured by using Visual Analogue Scale(VAS) and the range of motion was measured by using a rule for each group. Results: The results obtained were as follows The change in the pain perception degree were statistically significant in both group(p<0.05) ; however, the continuous wave ultrasound group showed more difference in the average decrease in the pain perception degree than did the pulsed wave ultrasound group. Both groups showed significant results regarding changed in the range of motion(p<0.05) ; Comparing the difference in the average of the range of motion between the two groups, came back from normal the range of motion of temporomandibular joint at the both groups. Conclusion : Based on the results of this study, we found that both groups showed decreased pain and increased the range of motion, but the continuous wave ultrasound method had a higher therapy effect pain and the range of motion than the pulsed wave ultrasound method to patients with temporomandibular joint disability. With such finding, we expect that according to ultrasound therapy applicant method can be helped usable accurately to patients with variety symptoms temporomandibular joint disability.

• The Journal of Korean Physical Therapy
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• 제16권4호
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• pp.179-201
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• 2004

The purpose of this study was to determine the effect of application methods in ultrasound on skin temperature and muscle blood flow. Thirty healthy volunteers without known vascular problems participated and randomly divided into three groups such as continuous wave group (CWG) which received a ultrasound treatment of continuous-wave, intermittent wave group (IWG) which received a ultrasound treatment of intermittent-wave at a dosage of $1.5\;W/cm^2$ for a duration of 5 minutes, and placebo group (PG) which received a ultrasound treatment of no-wave and no-dosage ultrasound to the anterior forearm. Blood flow and skin temperature was measured using MP 150 before and after ultrasound administration. The results were as follows : 1. Administration of ultrasound in all groups had increased effect on skeletal muscle blood flow immediately after treatment and for up to 10 minutes posttreatment. 2. CWG and IWG showed increased skin temperature immediately after a ultrasound administration and maintained to 10 minutes posttreatment. PG showed increased skin temperature immediately after a ultrasound administration but returned to initial state to 10 minutes posttreatment. 3. The great change on skeletal muscle blood flow among three groups showed in CWG ($6.27{\pm}1.72$) and then displayed in PG ($5.12{\pm}1.66$) and IWG ($4.61{\pm}2.19$) in order. 4. The vast change on skin temperature among three groups showed in CWG and then IWG and PG in order.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.516-519
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• 2001

환자를 진단하는데 있어 중풍, 고혈압, 동맥경화, 고지혈증 등 혈관 질환에 대해서 혈류에 관한 정보는 매우 중요하다. 초음파를 이용하여 혈류 속도를 측정하는 방법에는 연속 도플러 시스템과 펄스 도플러 시스템으로 나뉘어진다. 펄스 도플러 시스템은 혈류의 위치정보를 얻을 수 있지만, 연속 도플러 시스템에 비해 하드웨어적으로 복잡하고 신호대 잡음비가 낮으므로 본 연구에서는 신뢰적인 정보를 얻을 수 있는 연속 도플러 시스템을 이용하였다. 본 시스템은 크게 아날로그 부와 디지털 부로 나뉘어진다. 아날로그 부는 초음파 신호의 발생부, 초음파 센서로 수신된 신호를 증폭하는 증폭부와 혈류의 도플러 신호를 검출하는 복조부, 잡음 제거를 위한 필터부분으로 구성되어 있다. 디지털 부는 검출된 아날로그 신호를 디지털 신호로 변환하는 부분, 디지털 신호처리 부분 그리고 개인용 컴퓨터(Personal Computer)와 통신하는 부분으로 구성된다. 본 연구에서는 효율적인 초음파 혈류 속도 측정 시스템을 구현함으로써 환자의 혈류 정보를 실시간으로 인을 수 있으므로 뇌혈류 측정 등에 사용되는 전산화 단층 환영장치(Computered Tomography), 자기 공명 영상 촬영장치(Magnetic Resonance Imaging)와 같은 장비와 더불어 보다 정확한 진단을 하는데 유용하다.

• 대한의용생체공학회:의공학회지
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• 제32권3호
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• pp.264-269
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• 2011

To increase therapeutic efficiency and biological safety, it is important to precision control of acoustic output for therapeutic ultrasound equipment. In this paper, the electro-acoustic radiation conductance, one of electroacoustic characteristics of therapeutic ultrasound equipment, was measured by the radiation force balance method according to IEC 61161 standards and the acoustic output was estimated using the electro-acoustic radiation conductance. The estimation of acoustic output was conducted to continuous wave mode and pulse wave mode of duty cycle between 20% and 80%. The differences between prediction values and measurement results are within 5% of measurement uncertainty, which is a reasonably good agreement. The results show that acoustic output controlled by electro-acoustic radiation conductance was found to be an effective method.

• The Journal of Korean Physical Therapy
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• 제14권1호
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• pp.55-62
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• 2002

The purpose of this study was to determine the effects of the ultrasound on treatment of chronic sinusitis. 24 persons of men and women with chronic sinusitis divided into three groups of each 8 persons randomly and when were they were treated with the medication, the ultrasound(1MHz continuous wave, 1W/$cm^2$ intensity, three times per a week and once of three minutes circular stroke method) and the medication+ultrasound for 2, 4, 6 and 8 weeks. The results of this study were ad follows. 1. There was not statistical significant differences between the effects of treatment until two weeks(P>.05). 2. There was statistical difference between the effects of treatment after 4 weeks, 6 weeks and 8 weeks(P<.05). There was statistical significant difference between the group with ultrasound treatment and the group with ultrasound+medication treatment and there was statistical significant difference between the group with medication treatment and the group with ultrasound+medication treatment but there was not statistical significant between the group with ultrasound treatment and the group with medication treatment. 3. After 4 weeks, the highest effect for chronic sinusitis was group

• 한국생산제조학회지
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• 제21권2호
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• pp.252-258
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• 2012

A study of terahertz waves was made for the nondestructive evaluation of FRP (Fiber reinforced plastics) composite materials. The terahertz systems were consisted of time domain spectroscopy (TDS) and continuous wave (CW). The composite materials investigated include both non-conducting polymeric composites and conducting carbon fiber composites. Terahertz signals in the TDS mode resembles that of ultrasound; however, unlike ultrasound, a terahertz pulse was not able to detect a material with conductivity. The CFRP (Carbon fiber reinforced plastics) laminates were utilized for confirming the experimentation in the terahertz NDE. In carbon composites the penetration of terahertz waves is quite limited and the detection of flaws is strongly affected by the angle between the electric field direction of the terahertz waves and the intervening fiber directions. A refractive index (n) was defined as one of mechanical properties; so a method was obtained in order solve the "n" in the material with non-conductivity. The usefulness and limitations of terahertz radiation are investigated for the NDE of FRP composites.

• 한국생산제조학회지
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• 제21권1호
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• pp.102-108
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• 2012

A study of terahertz waves (T-ray) was made for the nondestructive evaluation of FRP (Fiber reinforced plastics) composite materials. The to-be-used systems were time domain spectroscopy (TDS) and continuous wave (CW). The composite materials investigated include both turbine blades of wind energy (non-conducting polymeric composites) and conducting carbon fiber composites. Terahertz signals in the TDS mode resembles that of ultrasound; however, unlike ultrasound, a terahertz pulse was not able to detect a material with conductivity. This was demonstrated in CFRP (Carbon fiber reinforced plastics) laminates. Refractive index (n) was defined as one of mechanical properties; so a method was solved in order solve the "n" in the material with the cut parts of the turbine blades of wind energy. The defects and anomalies investigated by terahertz radiation were foreign material inclusions and simulated disband. Especially, it is found that the T-ray went through the turbine blade with greater thickness (about 90mm).

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.867-876
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• 2019

Second harmonic generation using nonlinear ultrasonic waves have been shown to be an early indicator of possible fatigue damage in nuclear power plant components. This technique relies on measuring amplitudes, making it highly susceptible to variations in transducer coupling and instrumentation. This paper proposes an experimental procedure for in-situ surface wave nonlinear ultrasound measurements on specimen with permanently mounted transducers under high cycle fatigue loading without interrupting the experiment. It allows continuous monitoring and minimizes variation due to transducer coupling. Moreover, relations describing the effects of the measurement system nonlinearity including the effects of the material transfer function on the measured nonlinearity parameter are derived. An in-situ high cycle fatigue test was conducted using two 304 stainless steel specimens with two different excitation frequencies. A comprehensive analysis of the nonlinear sources, which result in variations in the measured nonlinearity parameters, was performed and the effects of the system nonlinearities are explained and identified. In both specimens, monotonic trend was observed in nonlinear parameter when the value of fundamental amplitude was not changing.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.258-263
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• 1999

In this study, the numerical and experimental investigations were conducted to understand ultrasonic wave propagation and to evaluate the degree of fiber waviness in thick composites nondestructively. The path, energy and traveling time of insonified wave were predicted by adopting the ray and plane wave theories. In the analysis, the composites were assumed to have continuous fiber with sinusoidal waviness in a matrix and were modeled as stacks of infinitesimally short length off-axis elements with varying fiber orientation along the length direction. From the experiments on the specially fabricated thick composite specimens with various degrees of uniform fiber waviness, the energy distributions of received wave were obtain for the various positions of transmitter. It was observed that the energy of wave was converged to the adjacent peaks of fiber waviness. The location where maximum energy of wave was detected from the experiments showed good agreement with the location obtained from theoretical predictions. Finally, the test procedure was Proposed to evaluate fiber waviness in thick composites by considering the energy of wave and relative distance between transmitter and receiver.

• 한국기계가공학회지
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• 제20권8호
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• pp.33-41
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• 2021

Recently, many studies have been conducted on substituting fossil fuels with bio-refineries in existing industrial systems using biomass. Among the various bio-refineries, microalgae have received wide attention because it uses inorganic compounds to produce useful substances, which are extracted by a cell disruption process. Although numerous cell disruption methods exist, cell disruption efficiency has been studied by ultrasonic treatment. Ultrasound is a high-frequency (20 kHz or higher) sound wave and causes cell disruption by cavitation when passing through a solvent. In this study, we used the microalgal species Chlorella sp., which was cultured in a plate-type photobioreactor. The experiment was conducted using a continuous low-frequency processing device. The reduction of cells with time due to cell disruption was fitted using a logistic model, and optimum conditions for highly efficient cell disruption were determined by conducting experiments under multiple conditions.