• International Journal of Automotive Technology
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• 제2권3호
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• pp.103-107
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• 2001

Many researches on pressure-swirl injectors due to the variety of application have been conducted on the effects of nozzle design, operating conditions, properties of liquid and ambient conditions on the flow and spray characteristics. The breakup length of conical emulsified fuel sheet resulting from pressure-swirl atomizer using in the oil burner was investigated with the digital image processing method with neat light oil and emulsion with water content of lotto% and the surfactant content of 1-3%. The injection pressure ranged from 0.1 to 1.2 MPa was selected. The various regimes for the stage of spray development within the experimental conditions selected in this study is newly suggested in terms of Ohnesorge number and injection pressure. The breakup length for both criteria show the same tendency even though the random nature of perforation and disintegration process of liquid sheet. The stage of spray development is widely different with the physical properties of liquid atomized, mainly viscosity of liquid. The breakup length decreases smoothly with increase in the injection pressure for the lower viscous liquid.

• 한국국방경영분석학회지
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• 제16권2호
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• pp.1-13
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• 1990

The life of an equipment depends upon its operating characteristics and physical environment factors. This paper presents the economic life length of 2 1/2 ton truck considering the operation terrains. For this specific research, the operation terrains are categorized into seacoast area, mountain area and plain area. To compute the life length, the method of equivalent annual cost is employed. The sample vehicles from each corresponding area are randomly selected from those vehicles whose ages exceed 9 years. This research finds the following results : (1) The life length operated at seacoast area is 9.75 years, (2) The life length operated at mountain area is 11.25 years, (3) The life length operated at plain area is 14 years. This research argues that the key factor such as characteristics of operating enviroment for allocation of operating and maintaining cost should be considered.

• 한국어교육
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• 제29권3호
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• pp.345-363
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• 2018

The purpose of this study is to compare the speech rate of advanced Korean(L2) learners and Korean native speakers in spontaneous utterances. Specifically, the current study investigated the difference of the two groups' speech pattern according to utterance length. Eight advanced Korean(L2) learners and eight Korean native speakers participated in this study. The data were collected by recording their conversation and physical measurements (speaking rate, articulatory rates, pause and several types of speech disfluency) were taken on extracted 120 utterances from 12 out of the 16 participants. The findings show that advanced Korean learners' speech pattern is similar to that of Koreans in the short-length utterance. However, in the long-length utterance, two groups show different speech patterns; while the articulatory rate of Korean native speakers increased in the long-length utterance, that of Korean learners decreased. This suggests that the frequency of speech disfluency factors might affect this result.

• Environmental Analysis Health and Toxicology
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• 제20권2호
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• pp.153-159
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• 2005

In order to evaluate the physical and mental health status of airline flight attendants, 136 airline flight attendants were given a general health questionnaire (Todai Health Index), and the prevalence of their subjective complaints was measured. Collected data were classified according to age distribution, length of employment, service area, smoking status, job satisfaction, gender, and marital status. The results obtained were summarized as follows: 1 The scores of health complaints of physical items were higher in the oldest group $(age 50\~60)$ than in younger groups. The THI eye and skin symptom scores were significantly higher for the oldest groups than for the younger groups. 2. The health complaints scores of physical items were higher in the long-length employment group (more than 5 years), whereas most scores of mental items were higher in the short- length employment group (less than 2 years). The THI mouth and anus scores for the long-length employment group were significantly higher than for groups of workers who had been employed for a shorter time. 3. THI scores were higher for domestic airline crews, dissatisfied workers and females. 4. The irregular life THI score was significantly higher among domestic crews than international crews. 5. The impulsiveness and depression scores were significantly higher in the dissatisfaction group. 6. The female group showed higher scores in the multiple subjective symptoms, mental irritability, depression, and irregular life categories. 7, The THI scores of the mouth, anus and nervousness were significantly higher for the married group than for the unmarried group. In summary, this study shows that the health complaints scores of physical and mental symptoms tended to be higher among the aged group, domestic airline crews, the dissatisfaction group, and females. These results can be used for improving the psychosomatic health status and working environments of flight attendants.

• 한국전문물리치료학회지
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• 제25권4호
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• pp.9-18
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• 2018

Background: Leg length discrepancy (LLD) leads to many musculoskeletal disorders and affects daily activities such as walking. In the majority of the population, mild LLD is a common condition. Nevertheless, it is still controversy among researchers and clinicians on the effects of mild LLD during gait, and available studies have largely overlooked this issue. Objects: The purpose of the present study is to investigate the effects of mild LLD on the gait parameters and trunk acceleration. Methods: A total of 15 female and male participants with no evidence of LLD of >.5 ㎝ participated in the present study. All participants walked under the following two conditions: (1) The non-LLD condition, where the participants walked in shoes of the same heel height; (2) A mild LLD condition induced by wearing a 1.5 ㎝ higher heel on the right shoe. The GAITRite system and tri-axial accelerometer were used to measure gait parameters and trunk acceleration. To compare the variation of each variable, a paired t-test was performed. Results: Compared to the non-LLD condition, step time and swing phase were significantly increased in the mild LLD condition, while stance phase, single support phase, and double support phase significantly decreased in the short limb (p<.05). In the long limb of the mild LLD condition, single support phase significantly increased, while swing phase significantly decreased (p<.05). Furthermore, significant decrease in the gait velocity and cadence in the mild LLD condition were observed (p<.05). In the comparison between both limbs in the mild LLD condition, the step time and swing phase of the short limb significantly increased compared with the long limb, while step length, stance phase, and single support phase of the long limb significantly increased compared with the short limb (p<.05). Additionally, trunk acceleration of all directions (anterior-posterior, medial-lateral, vertical) significantly increased in the mild LLD condition (p<.05). Conclusion: The results of the present study demonstrate that mild LLD causes altered and asymmetrical gait patterns and affects the trunk, resulting in inefficient gait. Therefore, mild LLD should not be overlooked and requires adequate treatment.

• 한국환경복원기술학회지
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• 제20권4호
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• pp.77-87
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• 2017

In this study, we investigated the physical form of planting foundation of the parks and green spaces in the waterside of Korea and classified them into groups showing common features. It was clssified into 7 kinds of parks and green spaces of 27 waterside parks in Korea including landscape, ecology, art, shields, site boundaries, windbreaks, and soundproofing. As a result, the study was carried out on the detailed type and size estimation through the sampling survey of planting foundation of landscape and ecological type mounding which can be statistically analyzed. Landscape and ecological mounding have the characteristics of securing the ecological stability of the waterside planting areas and the diversity of planting landscape. It is possible to create a green landscape through various terrain changes such as enclosing, focusing, and panoramic view. The physical characteristics of ecological and landscape type mounding can be expressed as height, width, and length And physical data can appear in various forms and sizes depending on the purpose and function of the buffer effect of the land use in the waterside planting areas, the landscape creation, the ecological buffer. In this study, the range of the physical scale for landscape and ecological mounding of waterside parks and green spaces was calculated. The range of the mounding height was analyzed to be less than 1.25m and more than 1.25m and the average height was 0.74~1.08m and 1.75~2.75m respectively. In addition, the range of width of mounding was less than 6.13m, 6.13~17.5m, and more than 17.5m, and the average width of each was 3.45~4.95m, 7.05~10.85m and 31.54~51.54m respectively. The range for the length of mounding was less than 50m, 50~500m, and more than 500m. The mean length of each mounding was 34.0m, 116.3m and 955.8m. It is difficult to distinguish the difference between the waterside planting areas and the urban greenery in the purpose and function of landscape and ecological mounding. However, considering the average distance of 60m from the waterside and the average height of 1.26m, we can conclud that opened planting foundation is prefered to high mounding designs in waterside planting areas. It is expected that the results presented for the improvement of the logical and spatial value of the waterside parks and green areas planting foundation design can be served as the basic data helpful for practical application in landscape architecture planning and design.

• 한국항공우주학회지
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• 제47권12호
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• pp.904-912
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• 2019

본 연구는 항공기에 근접하여 폭발하는 고폭형 위협 무기의 파편 발사속도 및 발사각을 수치 해석적으로 추정한 결과이다. 고폭형 위협 무기에 대한 항공기의 취약성을 평가하기 위하여 탄두 구성품의 물리량을 이해하는 것은 매우 중요하다. 일반적으로 고폭형 위협 무기에 대한 구성품의 질량, 길이 및 직경 등 물리적 변수는 알려져 있지 않다. Terrier, Sparrow 등 유사 위협 무기들의 데이터를 이용하여 charge to mass 비율, 길이와 직경 비율 등과 관련된 경험식을 수치 해석적으로 유도하였다. 근접신관에 의하여 외부에 폭발하는 탄두에서 탄두 덮개 구성비는 20% 수준으로 나타났으며, 고폭 화약의 양쪽 끝부분에서 방사되는 파편의 발사속도 구배 현상이 뚜렷이 나타났지만 법선 방향에 대한 발사각은 6° 이내로 나타났다.

• 센서학회지
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• 제18권1호
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• pp.86-94
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• 2009

Temperature measurement capability was inter-compared using the transfer standard platinum resistance thermometers(SPRT) among four laboratories of KRISS. The transfer SPRTs were primarily calibrated at the triple point of water and Ga melting point, then used at inter-comparison experiment. Temperature difference of calibration value between temperature laboratory and length laboratory at $20^{\circ}C$ was -0.7 mK and +2.4 mK at density laboratory. Temperature measured near $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$ at fluid flow laboratory was deviated by $34.2{\sim}80.4\;mK$ from the calibration values of the transfer SPRT. Ga melting points was inter-compared among three laboratories, and the difference of Ga melting points against the standard Ga melting point of temperature laboratory were $0.03{\sim}0.54\;mK$ at length laboratory and 0.02 mK at density laboratory.

• 대한물리의학회지
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• 제5권4호
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• pp.527-534
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• 2010

Purpose : The application of tape to modulation of pain and muscular excitability has become common clinical practice among musculoskeletal physical therapy. However, the techniques of the tape application has been relied on empirical evidence in preference to the neurophysiological evidence. Thus, the mechanism of taping has to be elucidated further. The aim of this study was to determine whether elastic and non-elastic taping across a muscle does indeed change ${\alpha}$-motor neuron excitability. Methods : The study was performed on 10 neurologically healthy adults. Two different types of tape were applied to skin overlying gastrocnemius. The elastic tape stretched up to 120% of its original length but non-elastic tape didn't stretched up of its original length. The tape applied across the direction on thickest part of the gastrocnemius. The ${\alpha}$-motor neuron excitability of the gastrocnemius was assessed using the gastrocnemius H-reflex. The amplitude of the M-wave and H-reflex were measured across three conditions: before tape application, with tape and with the tape removed. Results : No significant changes of the excitability of the ${\alpha}$-motor neuron were obtained across three condition, either in the elastic and non-elastic tape. Conclusion : From the results, I could come to the conclusion that further clinical work will be required.

• The Journal of Korean Physical Therapy
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• 제25권5호
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• pp.232-238
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• 2013

Purpose: The aim of this study was to evaluate the effect of lumbar stabilization exercise on an unstable surface on trunk posture and static standing balance ability in patients with scoliosis. Methods: Subjects included 18 patients who showed symptom of scoliosis. Patients were divided into two experimental groups, one using an unstable surface and one using a fixed surface, and the patients were required to perform a lumbar stabilization exercise a total of 12 times for 60 minutes per session, three times per week for a period of four weeks, with a six-months follow-up period. Results: A significant reduction was observed in the group that performed the lumbar stabilization exercise on an unstable surface (p<0.05). A significant decrease in both the condition of closed eyes or open eyes in the left and right directions was observed in the group that performed the lumbar stabilization exercise on an unstable surface (p<0.05). After six months, results of comparison of the length of both sides of the trunk showed a significantl decrease in the group performing lumbar stabilization exercises on an unstable surface. Conclusion: Lumbar stabilization exercise on an unstable surface improved the trunk posture of patients with scoliosis symmetrically, and static balance ability in a standing posture showed improvement. In the future, lumbar stabilization exercise on an unstable surface may be used as an exercise for posture correction and balance increase for patients with scoliosis.