• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1305-1313
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• 2000

In a co-rotating scroll compressor, both scrolls rotate on their fixed axes contrary to the conventional orbiting type scroll machine. This implies fixed locations and directions of the gas pressure force and sealing force. Because the tilting moment is mainly caused by interplay between the resultant force of above forces and bearing reaction force, the variation during one cycle is relatively small. Under real operation, this moment is balanced by the restoring moment created by the reaction between the baseplate and thrust bearing or between the scroll tip and baseplate. If these reactions become too large, greater torque is required due to increased friction in addition to the wear of mating parts. Consequently, appropriate study and minimization of tilting moment is important in the design of scroll machines. In this study, taking into account of the small variation of tilting moment during one cycle, we minimize the moment and thrust bearing reaction force by a properly designed back pressure chamber. As a result, for both the driving and driven scrolls, the tilting moment and the reaction force of thrust bearing can be minimized. And the stability is improved for all cases.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.2
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• pp.11-18
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• 2020

Background: The purpose of this study is to examine the correlation between high heels and body imbalance among female college students in their twenties who mainly wear high heels and prevent associated problems. Methods: The subjects included 89 female college students in their twenties. They were measured in plantar pressure with a gait analyzer. Their legs were measured in length with a tape measure. Their pain intensity and pain frequency were measured in visual analog scale and in pain rating score. Results: There were statistically positive correlations between right leg length and low back pain frequency (p<.05) and negative correlations between the left hindfoot and low back pain frequency (p<.05). There were statistically positive correlations between right leg length and knee pain frequency (p<.05) and positive correlations between the ankle pain intensity and right leg length (p<.05). Conclusion: The stronger the pain was in the ankle, the stronger and more frequent their lumber pain was. When the pressure of the left heel was lower, the frequency of lumbar pain increased.

• Journal of the Korean Geotechnical Society
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• v.28 no.12
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• pp.99-110
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• 2012

Inclined Earth Retaining Structure Method (IER method, briefly) is developed in order to improve the existing earth retaining method. In IER method, there are three main structures, front support, back support, and head binding. Especially, back support acts the role that reduces the earth pressure acting on the front support. In this study, the stability according to the installation angle and stiffness of front or back support is analysed by model tests. By the test results, it is known that inclined back support is very effective to reduce the earth pressure acting on the front support. Especially, the effect of the stiffness and installation angle of back support is analysed.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.3
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• pp.73-84
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• 2023

Background: This study aimed to compare pressure pain thresholds (PPTs) in the vertebral segments between patients with chronic lower back pain (CLBP) and healthy participants without back pain and to determine the correlation between vertebral bone-segment PPT and pain level, lower back pain dysfunction, and psychological status in patients with CLBP. Methods: The subjects of this study were 23 healthy adults and 23 adults with CLBP. PPT was measured in 23 spinal bone segments using a PPT device, and the CLBP group was subjected to a pain level test (NRS) and a psychological test using the Korean version of the pain catastrophizing scale (KPCS). The functional level was assessed using the Korean version of the Oswestry disability index (KODI). Results: PPTs of the spinal sclerotomes were significantly lower in patients with CLBP than in healthy participants. In the CLBP group, the composite score of lumbar PPTs showed a high correlation with the composite scores for all segments, but not with the pain level (NRS), KPCS score, and spinal sclerotome PPT. Moreover, PPT in the sacral sclerotomes showed a significant negative correlation coefficient with function, with a KODI score of -.462 (p<.01). Conclusion: In this study, PPTs in all spinal segments in patients with CLBP was significantly lower than that in healthy subjects. The PPTs of the lumbar region was significantly correlated with the PPTs of other spinal regions. Through this study, it was found that there were changes in PPTs in CLBP patients not only in the lumbar region but also in other spinal regions. This information should be considered during clinical treatment of patients with low back pain.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.6
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• pp.12-19
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• 2021

An experimental study was performed for a cavitating venturi supplying a constant rate of flow independent of downstream pressure fluctuations when providing liquid propellant. The venturi was designed and manufactured in order to figure out the performance of the cavitating venturi. Effects of the rear-end shape, upstream pressure, and back pressure on the ratio of downstream to upstream pressure of the venturi as well as the flow-rate were observed. As a result, critical pressure ratio of the venturi, which generally depends only on the configuration of the venturi, was kept at 0.74 regardless of the rear-end shape and the upstream pressure of the venturi.

• Journal of Acupuncture Research
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• v.23 no.2
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• pp.165-172
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• 2006

Objectives : This study was designed to estimate the effects of Spiral Taping theraphy on low back pain or neck pain patients by using pressure pain threshold, visual analogue scale(VAS), and range of motion(ROM). Methods : The patients were allocated into two groups by randomisation. Spiral Taping theraphy group consisted of 11 patients and acupuncture theraphy group consisted of 10 patients. The degree of improvement of neck pain was evaluated by pressure pain threshold, VAS, and ROM before treatment and after treatment. The patients were commonly treated with acupuncture theraphy. After acupuncture Spiral Taping theraphy was peformed in Spiral Taping theraphy group. Results : Pressure pain threshold and VAS were significantly different between two groups. In Spiral Taping theraphy group the pressure pain threshold of the all points was significantly increased and VAS was significantly decreased than control group. But there was no significant difference between the two groups in ROM. Conclusion : The effectiveness of Spiral Taping theraphy on low back pain and neck pain patients was shown through pressure algometer and VAS. These imply that Spiral Taping theraphy may be useful for on low back pain or neck pain. Further study is needed about Spiral Taping theraphy.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.8
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• pp.1060-1074
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• 2013

This study measured and analyzed pressure at each measurement part of imported compression stockings sold in Korea to provide basic information to establish a pressure standard and grade ranking. This study used 40 medical compression stockings imported from 6 countries. Pressure measurements were taken at 11 points: front side and back side of ankle, end-point of the gastrocnemius muscle, front, inner side, back, and outer side of calf, back side of below knew girth, inner side, and outer side of mid-thigh girth, and inner side of thigh girth. AMI 3037-10 and AMI 3037-2 were used for measurements taken inside an environmental chamber at a temperature of $21^{\circ}C$ and a relative humidity (RH) of 65%. For the measurements, 11 air pack sensors were attached to a wooden model leg (Hohenstein) and three measurements were taken at each measurement point in three minutes. The average of these measurements was used for analysis. The findings of this study were as follows. As for the front side of the ankle, of the 40 products, 14 products (6 USA, 2 Swiss, 3 Italian, and 2 Taiwanese) were within the pressure range indicated on the product label; however, no German products fell within the pressure range. A total of 8 products (5 USA, 1 Swiss, 1 Italian, and 1 German) were gradient compression type; however, no Japanese or Taiwanese product were of this type. The majority of products had the highest pressure at the end-point of the gastrocnemius muscle. Only 3 products, 1 USA (Jobst Opaque 30-40mmHg), 1 Swiss (Sigvaris Cotton 34-46mmHg) and 1 Italian (Jobstocking 25-32mmHg), had measurements that met the indicated standard pressure, were a gradient compression type, and met the overall standard for compression stockings.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.1
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• pp.81-87
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• 2012

The structural and biomechanical characteristics of pelvic and foot are important factors of back pain, but it is still complicated to clearly explain the relationship among them. The purpose of this study was to find out the characteristic of pelvic parameters and biomechanics of foot in patients with low back pain. Thirty-three female subjects with chronic low back pain were enrolled and ODI and VAS score were measured for back pain index. All subjects were taken the X-ray examination for major pelvic parameters and foot scan analysis for foot pressure, gait angle, fore-foot/rear-foot peak pressure ratio and asymmetric index. Statistical analysis were performed to examine the inter-relation between the measurement. As a result, it was shown the positive interrelation between back pain and F/R ratio, but others were not shown the relationship related to low back pain. And there were correlations between the lumbo-pelvic structure and biomechanics of foot in some aspects, but the causal relationship between them are still indefinable. In order to get more information about structures and biomechanics related to low back pain, subsequent researches are needed.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.16-21
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• 2005

The performance of reciprocating internal combustion engine is a strong function of the air intake system configuration. In order to improve engine power, it is essential to optimize the air induction system. In this study, a numerical investigation has been carried out for the three-dimensional flow and pressure characteristics in air intake system of a large-sized commercial bus. CFD simulations using STAR-CD were also perform ed to evaluate effects of intake duct geometry and structure variation inside air cleaner on the negative pressure distribution of overall intake system. Studies for improving the back pressure distribution have been proposed and quantitatively examined based on intensive case studies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.175-182
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• 2002

The cement injection technology on the purpose of ground reinforcement and cut-off has been used in construction sites until now. However, recently it is applied to prevent leakage of underground structure. In this study, applicability of the back side waterproof grouting method was verified through performing field model tests and reviewing case histories. From the results of this study, injection shape of the back side waterproof grouting method was appeared to be root type, and waterproof effect by injection of cement grout material was excellent because grout material infiltrated into boundary between wall of structure and back side ground to be waterproof layer. Components influencing infiltration of injection material are type of soil and degree of compaction. For effective injection, injection pressure has to vary gradually from high pressure to low pessure and small quantity of injection material has to be injected for long times. Also, spacing of injection hole must be designed considering condition of back side ground, injection area, W/C ratio, the number of injection and injection pattern properly.