• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.223-228
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• 2001

The thermoacoustic refrigerator has not only considerable possibility but also commercial usability, because it has high reliability, lower vibration, no moving part, and can easily be constructed. In this study, The thermoacoustic refrigerator were constructed. The apparatus is capable of driving closed systems containing He or air at mean pressures ranging from 1-9.3 bar, at frequencies ranging from 100-1000Hz. The resonance characteristics of the thermoacoustic refrigerator were investigated for better performance, The resonance tube is 340.5mm in length. In case of using air as a coolant. Freezing frequency is 174Hz, In case of using He as a coolant Freezing frequency is 625Hz. Using He, The cold-part temperature of the heat exchanger fell to $-23.7^{\circ}C$ after 120 minutes in 70W.

• 수산해양기술연구
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• 제59권1호
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• pp.35-43
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• 2023

Sensory evaluation of shucking pressure, pressure holding time, seeding method, difference in full shucking rate in the aquaculture area and shucking oyster was performed using an ultra-high pressure oyster shucking machine. The reaching time for each target pressure is 2.2-2.4 MPa/sec in the range of 180 MPa to 240 MPa. had a rate of pressure rise. There was a difference of 0.5-1.7℃ in the range of 24-27℃ in the seawater temperature before and after the pressure treatment inside the pressure vessel, but there was no specific increase or decrease in seawater temperature. When only the shucking pressure is increased without the pressure holding time, the critical shucking pressure at which the oyster shell is opened and the flesh is peeled in the range of 200 to 220 MPa. When the critical shucking pressure is reached, the oyster sample in the closed vessel is expected to be shucked by about 40%. If there is no pressure holding time when judged only by full shucking, an increase in pressure of about 1.5 MPa is required to further shuck 3% of the oyster population. The oyster samples cultivated in the south coast of Korea were subject to full shucking under the conditions of 220 MPa shucking pressure and two minutes (120 seconds) of pressure holding time, and the difference in the pressure of the oysters according to the oyster seeding method and the farming area was minute. Finally, the condition of 220 MPa of shucking pressure and three minutes of pressure holding time was the best at 1.52 when the result of the sensory evaluation performed manually was set to 1.0. Next was 1.4 under the conditions of 220 MPa of shucking pressure and one minute of pressure holding time (60 seconds), and 1.3 under the condition of 220 MPa and two minutes of pressure holding time (120 seconds). Therefore, it is considered that the most desirable shucking conditions, considering the efficiency and sensory evaluation results, are the conditions of 220 MPa shucking pressure and two to three minutes of pressure holding time.

• Restorative Dentistry and Endodontics
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• 제27권5호
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• pp.535-542
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• 2002

The purpose of this study was to evaluate the effect of EDTA irrigant according to application time and temperature. 31 human mature extracted teeth with a single canal were sectioned with microtome in 3mm thickness and gained 62 samples of root canals. They were distributed randomly into 6 groups of 10 specimens each and control group of 2 specimens. Each specimen was prepared with GT rotary file (Dentsply, Maillefer Co., Swiss) and irrigated with 3 ml sodium hypochlorite every minute. Then smear layer was removed with EDTA solution (PULPDENT$^{\circledR}$, PULPDENT Co., USA.) except two control specimens. Specimens of each group were irrigated with 17% EDTA. The time and temperature of application were as follows : (Table omitted) All specimens were split longitudinally and prepared for examination by scanning electron microscopy. A set of reference micrographs was used to award a debris score as follows: 0 = no smear layer, all tubules clean and open; 1 = no superficial smear layer, tubule openings visible, but some contain debris plug or soft tissue remnants: 2 = moderate smear layer, some tubules open and others closed; 3 = heavy smear layer, most/all tubule openings obscured. Results were evaluated with Kruskal-Wallis test to determine whether there was statistically significant difference among six groups. Pairs of groups were analyzed using the Student-Newman-Keuls Method and Mann-Whitney test. The results were as follows : 1. Control specimens showed heavy smear layer at the canal walls 2. Among the groups applied with EDTA for 2 minutes, group 1 showed the heaviest smear layer, and there was statistically significant difference between group 1 and the other groups(p<0.05). 3. Among the groups applied with EDTA for 5 minutes, group 4 and group 6 showed smear layer but there was no significant difference between them. 4. Among the groups applied with EDTA for the same temperature, group 1 showed heavier smear layer than group 4, and there was statistically significant difference(p<0.05). 5. Among the groups applied with EDTA for the same temperature, group 2 showed heavier smear layer than group 5 and group 3 showed heavier smear layer than group 6. But there was no statistically significant difference among them. From the results above, it could be concluded, EDTA solution is effective in removing of smear layer when it is applied for 5 minutes. If EDTA is applied for 2 minutes, it should be applied above room temperature.

• Journal of Chest Surgery
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• 제13권1호
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• pp.60-65
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• 1980

We have experienced 2 cases of the hunshot wound sof the chest involving cardiac injuries at department of the thoracic surgery, Capital Armed Forces General Hospital during I year from April I 1979 to Jan. 1980. In one case of two patients , he was a 22 years old man who was transported to this emergency room 4 hour 10 minutes after having gunshot wound of the left chest by helicopter. Physical examination showed small inlet in left 3rd ICS and left parasternal border, large outlet in left 8th ICS and left scapular line, no breath sound on left side and distant heart sound. chest roentgenography demonstrated marked pleural effusion in left side and mediastinum shifted to right. As soon as chest X-ray was taken, the bleeding through penetrating wound became profuse and cardiac arrest ensued. Closed chest cardiac massage was started and vigorous transfusion continued, but no effective cardiac activity could not be obtained. The patient was pronounced dead due to exsanguinating hemorrhage from wuwpected cardiac wounds. In this critically injured patient with evidence of intrathoracic hemorrhage and suspected cardiac penetration, only emergency thoracic exploration and immediate surgical control of bleeding points might offer the maximum possibility of survival. The other case was a 23 years old man who was transferred to the emergency room 4 hours 50 minutes after having kmultiple communicated fractures of sternum and linear fracture of right mandible by a missile. Examination revealed about 30% skin loss of the anterior chest wall, weak pulse of 96 beats/min., distant heart sound and decreased breath sounds bilaterally. finding on the chest X-ray films showed multiple sternal fractures, marked pericardial effusion indicating hemopericardium. So, the patient was moved immediately to the operation room where, after endotracheal tube inserted, a median sternotomy was performced. A hemorrhagic congestion of the right upper lobe and marked bulging pericardium were disclosed. The pericardium was opened anterior to right phrenic nerve and exsanguinating hemorrhage ensued from the 0.5cm lacerated wound in the auricle of right atrium. The rupture site of right atrium was occluded with non-crushing vascular clamps and then was over sewn with interrupted sutures. It was thought to be highly possible that he was alive long enough to have cardiorrhaphy because of cardiac tamponade, which prevented exsanguinating hemorrhage. He was taken closed reduction for linear fracture of right mandible 2 weeks after repair of ruptured right auricle in dental clinic. This patient's post-operative course was not eventful.

• Journal of Chest Surgery
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• 제31권9호
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• pp.827-836
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• 1998

배경: 고려대학교 흉부외과학교실에서는 심폐소생술에서 인공심 사용이 기존의 표준 심폐소생술에 비해 나은 결과를 보인다는 점에 착안하여 한국형 이동식 심폐소생기를 개발하고자 하였다. 1997년 1월부터 8월까지 한국형 이동식 심폐소생기 개발의 전단계로 심폐정지 모델 결정 및 표준 폐쇄식/ 개흉식 심폐소생술의 비교와 관찰지표 설정을 위한 준비실험을 실시하였다. 대상 및 방법: 실험은 한국산 잡견 9마리(28-35kg)를 대상으로 폐쇄식 심폐소생술군 4마리와 개흉식 심폐소생술군 5마리로 나누어, 4분 간의 심정지 및 15분간의 일차 심폐소생술(basic life support; BLS)과 30분간의 이차 심폐소생술(advanced life support; ALS)을 실시하였다. 심장압박은 폐쇄식군의 경우 흉부에 압박을 가하였고 개흉식군에서는 직접 심장을 맛사지하였다. 소생술기간에 양군 모두 동일한 조건의 폐환기 상태를 유지하였으며, 자발성 순환회복은 이차심폐소생술 기간 초기부터 재세동과 에피네프린 및 탄산수소 나트륨을 투여하여 유도하였다. 결과: 심폐소생술 기간안에 평균 체동맥압은 BLS 동안 폐쇄식군이 33$\pm$11 mmHg인데 비해 개흉식군은 45$\pm$15 mmHg로 높게 유지되었으며, ALS 동안에도 폐쇄식군 44$\pm$15 mmHg에 비해 개흉식군이 83$\pm$36 mmHg로 높게 유지 되었으나 통계상의 유의성은 없었다. 한편 평균 폐동맥압은 BLS 동안 폐쇄식군에서 32$\pm$10 mmHg로 평균 체동 맥압과 비슷한 정도로 증가하였으나 개흉식군은 22$\pm$4 mmHg로 평균 체동맥압의 약 50%정도까지만 증가하였고, ALS 동안에도 폐쇄식군은 32$\pm$15 mmHg로 개흉식군의 24$\pm$10 mmHg보다 높게 유지되었으나 통계처리상 유의성 은 없었다. 자발성 순환회복(restoration of spontaneous circulation; ROSC) 및 심폐소생 성공 여부에서 폐 쇄식군은 4마리 모두 사망하였으나 개흉식군은 5마리중 4마리가 생존하였고 생존기간은 384$\pm$705시간이였다 (p<.05). 결론: 본 연구 결과 개흉식 심폐소생술은 폐쇄식 소생술에 비해 비록 통계학상의 차이는 없었으나 소생술 기간 동안 비교해서 안정된 혈역학 상태를 유지하여서 자발성 순환회복 및 장단기 생존율을 향상시킬 수 있었다고 판단된다.

• Journal of Chest Surgery
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• 제9권2호
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• pp.220-238
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• 1976

Six cases of congenital heart disease were operated on by means of cardiopulmonary bypass between December, 1975 and April, 1976. Two cases of ventricular septal defects (VSD), two cases of VSD, associated with ruptured aneurysm of sinus Valsalva, two cases of atrial septal defects (ASD) and one case of pulmonic stenosis with patent ductus arteriosus were operated. Sarns roller pumps and Bentley Temptrol oxygenators were used for extracorporeal circulation. Pump oxygenator was primed with Ringer's lactate solution, 5% dextrose in water, mannitol, and ACD blood. Flow rate ranged from 2.0 to $2.4L/M^2/min$. Bicarbonate was added to the oxygenator with estimated amount as 15 mEq/L/hr. Venous catheters were introduced into superior and inferior vena cava, and oxygenated blood was returned to the body through aortic cannula inserted into ascending aorta. Moderate hypothermia ($30^{\circ}C$) was induced by core cooling. Aorta was cross clamped for 15 minutes and released for 3 minutes, and repeated clamping when necessary. Atrial and ventricular septal efects were closed by direct sutures. Aneurysms of sinus Valsalva ruptured into the right ventricle were repaired through right ventriculotomy by d:rect closure with Dacron patch reinforcement. Cardiopulmonary bypass time varied from 66 to 209 minutes, and aorta cross clamping time ranged from 13 to 56 minutes. Postoperative bleeding was minimal except one case who needed for evacuation of substernal hematoma. Intra- and postoperative urinary output was satisfactory. Acid-base balance, partial pressure of $O_2$, electrolytes, and hematological changes during intra- and post-perfusion period remained at the acceptable ranges. No mortality was experienced.

• The Journal of Korean Physical Therapy
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• 제32권4호
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• pp.238-244
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• 2020

Purpose: This study compared the effects of the fascial distortion model (FDM), foam rolling (FR), and self-stretching (SS) on the ankle dorsiflexion range of motion (ROM). Methods: Thirty subjects who had no more than 30° of ankle dorsiflexion ROM at the weight-bearing lunge test were recruited in this study. They were divided into three groups: (FDM, FR, and SS), and underwent each intervention for five minutes. Before and after the intervention, the ankle dorsiflexion ROM in the supine (the open-) and standing (the closed-kinetic chain) of the subjects were tested. The changes in the ROM between pre- and post-intervention and among the groups were analyzed. Results: All groups showed increased ankle dorsiflexion ROM after the intervention in both positions. In the position of the open kinetic chain, the changes in the ROM between pre- and post-intervention had significant differences among the groups, and the FDM was higher than the FR and SS. In the position of the closed kinetic chain, the ROM after the interventions and the changes in the ROM had significant differences among the groups, and FDM was higher than the FR (ROM after the intervention, the change in ROM) and SS (the change in ROM). Conclusion: These findings showed that FDM had more efficiency than the FR and SS as FDM had a stronger effect on increasing ankle dorsiflexion in a short, limited time. Clinicians who have limited time to treat their patients, particularly trying to increase ankle dorsiflexion ROM, should consider the application of FDM.

• Archives of Plastic Surgery
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• 제37권4호
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• pp.369-374
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• 2010

Purpose: Most of the patients who underwent surgery feels variable kinds of fear or anxiety; an uncomfortable mood state that happens without specific object affects patient's satisfaction before and after the surgery. As music therapy is rather noninvasive method generally used in reducing patient's anxiety, the authors researched about the extent of anxiety with the change of vital sign before the operation while comparing with the cases of patients who took the music therapy at closed reduction under general anesthesia. Method: We divided the patients in 4 groups; A with the premedication (Midazolam, Dormicum$^{(R)}$) before the operation, B with the premedication and music therapy, C with only music therapy, D with no premedication or therapy. And we measured the vital signs after the arrival at the operation room, after induction and 20 minutes after the operation. Also we observed the changes of anxiety index with the STAI (State Trait Anxiety Inventory)-K (Korea)YZ 1 hour before and 8 hours after the surgery. Result: The group B showed the least changes in blood pressure as the group D showed the highest change. Both group C and A showed increase in blood pressure but the upswing in group A was lower than group C. At the change of pulse rate group B showed the lowest upswing also group D showing the highest. Group B showed quite a few upswing but lower than group D, but, at the same time, group A showed lower upswing when comparing two cases. After analysis of STAI-KYZ score, the anxiety relatively decreased in group B and C in comparison with group D. And the index of anxiety state of group A showed just as much to group D. Conclusion: The music therapy is better healthcare method compared to other therapies in reducing anxiety also with satisfying effect who underwent operation. The authors recommend music therapy assisted with use of premedication for better relief of anxiety.

• 대한물리의학회지
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• 제7권1호
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• pp.59-67
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• 2012

Purpose : This study was somatosensory less in patients with idiopathic scoliosis somatosensory input to the lumbar stabilization exercises carried out to determine the most effective treatment method to be stable and unstable in terms of supporting the lumbar stabilization exercises the patient's torso length and postural sway by comparing the distance from a standing position and looked for differences in effect on the balance. Methods : The subjects of the study were 18 patients who showed the symptom of scoliosis. The study classified the patients into two experimental groups, one using an unstable surface and one a fixed surface, and the patients were required to do a lumbar stabilization exercise a total of 12 times for 60 minutes per session, three times a week for four weeks. The study carried out a paired comparison t-test so as to compare differences between measurement values in each experimental group before and after the exercise. Results : Superior iliac spine on the left, there was a significant reduction in the group doing the lumbar stabilization exercise on an unstable surface (p<0.05). Regarding change in sway distance to the left and right directions in the group doing the lumbar stabilization exercise on the unstable surface, there was a significant decrease in both the condition of closed eyes or open eyes (p<0.05). As for change in sway distance in forward-and-backward direction, there was a significant reduction in the condition of either closed eyes or open eyes (p<0.05). Conclusion : The lumbar stabilization exercise on an unstable surface improved the trunk posture of patients with scoliosis symmetrically, and the static balance ability in a standing posture was discovered to be improved. In the future, the lumbar stabilization exercise on an unstable surface may be used as a posture correction and balance increase exercise for patients with scoliosis.

• 대한물리치료과학회지
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• 제25권1호
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• pp.1-10
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• 2018

Background: The purpose of this study was to ascertain the effects of core program exercise on balance in patients with chronic low back pain. Thirty-four subjects participated in this study, these subjects were assigned into two groups, a control group(n=17) and an experimental group(n=17). Methods: The subjects in the control group were received a conservative physical therapy and in the experimental group carried out the core program exercise for 30 minutes per day, three times a week during 6 weeks. In order to evaluate the progresses of balance ability, corresponding variables were measured at two times, pre and 6th week. The balance ability was assessed using GOOD BALANCE system. The collected data were analyzed by using the paired t-test and ANCOVA. In all statistical analyses, significance level, ${\alpha}$ was set by 0.05. Results: The results of this study were as follows: 1) In the position of left standing eye closed, there were significant difference of Y in the control group and X, Y, V in the experimental group. 2) In the position of right standing eye closed, there were significant difference of Y in the control group and X, Y, V in the experimental group. 3) In the position of dynamic balance 1, there were significant difference APV in experimental groups. 4) In the position of dynamic balance 2, there were significant difference MLV in experimental groups. 5) There were significances between the two group of X, V in static balance and APV in dynamic balance. Conclusion: The above results indicated that a core program exercise improved balance abilities in patients with chronic low back. The further studies should be focused at development of various modified forms of the core program exercise in keeping up the improvement effect of this exercise.