• 소성∙가공
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• 제29권3호
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• pp.163-171
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• 2020

We present a multi-step cold drawing for a non-equiatomic Co₁₀Cr₁₅Fe₂₅Mn₁₀Ni₃₀V₁₀ high entropy alloy (HEA) with a simple face-centered cubic (FCC) crystal structure. The distribution of strain in the cold-drawn Co₁₀Cr₁₅Fe₂₅Mn₁₀Ni₃₀V₁₀ HEA wires was analyzed by the finite element method (FEM). The effective strain was expected to be higher as it was closer to the surface of the wire. However, the reverse shear strain acted to cause a transition in the shear strain behavior. The critical effective strain at which the shear strain transition behavior is completely shifted was predicted to be 4.75. Severely cold-drawn Co₁₀Cr₁₅Fe₂₅Mn₁₀Ni₃₀V₁₀ HEA wires up to 96% of the maximum cross-sectional reduction ratio were successfully manufactured without breakage. With the assistance of electron back-scattering diffraction and transmission electron microscope analyses, the abundant deformation twins were found in the region of high effective strain, which is a major strengthening mechanism for the cold-drawn Co₁₀Cr₁₅Fe₂₅Mn₁₀Ni₃₀V₁₀ HEA wire.

• 한국분무공학회지
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• 제25권1호
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• pp.8-14
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• 2020

Recently, 1-D model-based engine development using virtual engine system is getting more attention than experimental-based engine development due to the advantages in time and cost. Injection rate profile is the one of the main parameters that determine the start and end of combustion. Therefore, it is essential to set up a sophisticated model to accurately predict the injection rate as starting point of virtual engine system. In this research, procedure of 1-D model setup based on AMESim is introduced to predict the dynamic behavior and injection rate of diesel injector. As a first step, detailed 3D cross-sectional drawing of the injector was achieved, which can be done with help of precision measurement system. Then an approximate AMESim model was provided based on the 3D drawing, which is composed of three part such as solenoid part, control chamber part and needle and nozzle orifice part. However, validation results in terms of total injection quantity showed some errors over the acceptable level. Therefore, experimental work including needle movement visualization, solenoid part analysis and flow characteristics of injector part was performed together to provide more accuracy of 1-D model. Finally, 1-D model with the accuracy of less than 10% of error compared with experimental result in terms of injection quantity and injection rate shape under normal temperature and single injection condition was established. Further work considering fuel temperature and multiple injection will be performed.

• 한국재료학회지
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• 제11권2호
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• pp.115-119
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• 2001

다발체형성 제조기술을 이용하여 심하게 인발가공된 Cu-Nb 미세복합재료 전선의 전기적 특성과 열처리에 따른 미세조직 변화와의 관계에 대하여 연구하였다. 다발체형성과 인발공정에 의해 제조된 전선에서 Nb필라멘트 단면방향의 형태는 직선이거나 약간 굽은 형태로 나타났다 Nb필라멘트 형태의 차이는 고온에서의 다발체형성 제조공정중의 Nb필라멘트의 파손과 실린더화에 의해 발생하였다. Cu-Nb 미세복합재료의 비저항은 Cu-Nb 계면에서의 전자 산란에 의해 주로 결정된다. $400^{\circ}C$의 어닐링온도 이하에서 전도도의 감소는 침상형태 석출물의 정합변형율과 관계된 산란의 기여가 증가하기 때문이다. 비저항의 비 ($\rho_{295K}$/$\rho_{75K}$)의 약간의 감소는 또한 Nb원자의 석출 때문이다. 50$0^{\circ}C$의 어닐링온도에서 Cu-Nb 미세복합재료의 전도도 중가는 Nb필라멘트의 조대화와 구형화때문이다

• Physical Therapy Rehabilitation Science
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• 제3권2호
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• pp.101-106
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• 2014

Objective: To investigate the appropriate position for abdominal drawing-in maneuver (ADIM) exercise by rehabilitative ultrasound image. Design: Cross-sectional study. Methods: Twenty-eight young adults with no history of low back pain participated in the study. Three positions compared were crook lying position with hip $60^{\circ}$ flexion, standing position with the feet hip width apart and knees straight, and saddle standing positionunsupported with the knees $20^{\circ}$ flexed. Once in the appropriate position, the subjects were verbally cued to draw in their abdominal wall, with the intention of pulling their navel inward toward their lower back. The thickness of each transversus abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles were measured via ultrasound and recorded at the end of inspiration. Results: When compared to the TrA thickness of rest, the TrA thickness was significantly increased in all three positions (crook lying, standing, and saddle standing) during the ADIM (p<0.05). IO thickness was significantly greater in standing and saddle standing than in crook lying (p<0.05). EO thickness was constant in all the three positions. Conclusions: The present study suggests that standing and saddle standing positions could be recommended for the ADIM to maximize recruitment of the TrA and IO activation. Specifically, the saddle standing position with knees flexed to $20^{\circ}$ was observed to increase the TrA activation more than the standing position. These findings should be considered when core stability exercises such as the ADIM are conducted.

• Physical Therapy Rehabilitation Science
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• 제11권4호
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• pp.526-534
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• 2022

Objective: The purpose of this study was to compare muscle activities of stroke patients and healthy participants during bimanual tasks. Design: A cross sectional study. Methods: A total of 25 participants (13 hemiparetic stroke patients and 12 healthy participants) were recruited. The muscle activities using electromyogram (EMG) during bimanual tasks were collected from the following muscles: extensor carpi radialis longus (ECRL), biceps brachii (BB), and triceps brachii (TB). The bimanual tasks included eight tasks consisted of (1) raising the wrists up and down, (2) supinating and pronating the palms, (3) touching the shoulder with fingertips, (4) drawing vertical dot, (5) reaching for a cup and bring it in to drink, (6) drawing a circle outward and (7) inward, and (8) grasping the fingers. The EMG data collected from the muscles of paretic and non-paretic sides of stroke patients and the average from both sides of healthy subjects were normalized and compared after calculating the percentage of maximal isometric voluntary contraction. Results: The ECRL, BB and TB of the paretic side of the stroke patients showed relatively greater muscle activity compared to the non-paretic side as well asaverage of the healthy subject duringall tasks (p<0.05). In addition, the ECRL showed the highest muscle activity during most of the tasks. All of the non-paretic side musclesfrom stroke patients showed higher muscle activity compared to those of healthy subjects. Conclusions: The current study showed that muscle activities of upper extremity varied between paretic and non-paretic sides of stroke patients during bimanual tasks. Interestingly, the non-paretic side muscle activities were also different from those of normal participants.

• Journal of Korean Biological Nursing Science
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• 제16권2호
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• pp.69-79
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• 2014

Purpose: The purpose of this descriptive, cross-sectional study was to examine Korean undergraduate nursing students' perceived knowledge and attitudes toward genetics. Nursing competencies for genetics among nursing students were also assessed. Methods: Two hundred eighty-six Korean junior and senior undergraduate nursing students who went through their clinical practicum completed a packet of self-report questionnaires exploring opinions about the integration of genetics into the nursing curriculum, as well as their perceived knowledge, attitudes, and nursing competencies toward genetics. Collected data were analyzed using descriptive statistics, t-test, one-way ANOVA. Results: Overall, Korean undergraduate nursing students reported limited genetic knowledge, but most of them were comfortable with drawing pedigree. In general, nursing students were competent in providing genetic nursing. Their genetic nursing competencies were significantly different depending on the level of general understanding of genetics. There was no significant difference between juniors and seniors regarding knowledge, attitudes, and competencies toward genetics. More than 60% of nursing students reported the need for genetic nursing, and the majority considered lectures to be the most effective method to learn genetic knowledge. Conclusion: It is imperative to integrate genetics into nursing curriculum in order to improve nursing students' genetic nursing competencies as well as genetic knowledge.

• The Journal of Asian Finance, Economics and Business
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• 제7권5호
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• pp.291-304
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• 2020

This paper examines the factors that drive temporal income diversification in rural areas of the Mekong River Delta in Vietnam, based on a framework that conceptualized diversification as a function of a household's capacity to diversify and incentives (both push and pull factors) to diversify. Drawing from five rounds of the Vietnam Living Standard Measurement Surveys covering a 13-year span (1993-2006), two panel datasets made from five cross-sectional samples are used for the analyses. The data are drawn from the Vietnam General Statistics Office. Both tobit model and Ordinary Least Squares model with random and fixed effects are applied. The main points emerging from the analysis is that income diversification is strongly influenced by household labor capacity. The relationship between household labor capacity and increasing insertion in non-farming wage activities is not driven by unobserved time-invariant factors such as household ability and motivation, but is instead driven by the higher labor capacity of households. In terms of the other household capacity variables, the effect of farm size is much larger in terms of retaining households in traditional occupations as compared to pushing them towards non-farm wage employment. Other variables such as household access to financial capital do not play an important role.

• 여성건강간호학회지
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• 제17권5호
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• pp.474-483
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• 2011

Purpose: To examine the details of lymphedema, upper limb morbidity, and its self management in women after breast cancer treatment. Methods: Using a cross-sectional survey design, 81 women were recruited from a university hospital. Lymphedema was detected by a nurse as a 2-cm difference between arm circumferences at 6 different points on the arm. Degrees of pain, stiffness, and numbness were scored using a drawing of upper limb on a 0~10 point scale. Aggravating conditions and self-management for lymphedema were also recorded. Results: The mean age of the participants was 52.5 years; the average time since breast surgery was 29.7 months. Histories of modified radical mastectomy (55%) and lymph node dissection (81%) were noted. Lymphedema was found in 59% of women, then pain and stiffness were prevalent most at upper arm while numbness was apparentat fingers, and the symptom distress scores ranged 3.9~6.7. Women experienced aggravated arm swelling after routine housework with greatly varied duration. Self-management was conservative with a wide range of times for the relief of symptoms. Conclusion: Lymphedema education for women with breast cancer should be incorporated into the oncologic nursing care system to prevent its occurrence and arm morbidity. Risk reduction guidelines, individually tailored self-care strategies, and self-awareness for early detection need to be refined in clinical nursing practices.

• 산경연구논집
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• 제12권8호
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• pp.33-39
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• 2021

Purpose: The influence of age on time preference is not identified in the usual cross-sectional analysis. This study aims to test whether age affects time preference after controlling for the effects of individual heterogeneity including cohort effects. Research design, data and methodology: Drawing on a nationally representative panel dataset of Indonesians, we estimate the effects of age on time preference after controlling for unobserved individual heterogeneity as well as potential cohort effects. We measure time preference exploiting information on two sets of multiple price lists: one for a one-year delay, and the other for a five-year delay. Results: When we controlled for time-invariant individual characteristics, including birth cohort effects in a fixed effects model, the older men and women were more patient in a linear fashion, particularly when the delay was longer. To highlight the importance of controlling for individual fixed effects, we repeated the specification without controlling for individual fixed effects in OLS or censored maximum likelihood regression; we found no relation between age and impatience in men or women and for a one or five-year delay. Conclusions: The older men and women are more patient, and time preferences are correlated with unobserved individual heterogeneity.

• Physical Therapy Rehabilitation Science
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• 제11권4호
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• pp.546-552
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• 2022

Objective: The purpose of this study was to compare walking speed and balance abilities according to various taping methodsin patients with stroke. Design: Cross-sectional study Methods: Twenty patients with stroke who were hospitalized at a rehabilitation hospital were allotted to the either the talus stabilization, Kinesio or sham taping, or barefoot conditions by drawing lots. Assessment tools used were the Functional Reach Test(FRT), Timed Up and Go test(TUG), One-Legged Stance Test (OLST), and the 10-Meter Walk Test(10MWT).After each test was measured three times, the mean values of each test was used for analysis. Results: Significant results were observed with thetalus stabilization and Kinesio taping groupcompared to the barefoot and sham taping method for theFRT,TUG, the OLST, and the 10MWT(p<0.05). Also, significant differences in the resultswere seen in the OLST, TUG, and the 10MWTwith the talus taping compared to the Kinesio taping method(p<0.05). Conclusions: The use oftalus stabilization taping applied to the ankle of patients with stroke was more effective for balance and walking ability improvement than Kinesio taping through the correction of an abnormal position of the talus.It is considered that these methods of taping can be applied effectively in the clinic.