• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.61-66
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• 2004

The objective of the present study is to develop methodology for the assessment of combustion stability of liquid rocket injectors. To simulate actual combustion occurring inside of a thrust chamber, a fullscale injector has been employed in the study, which bums gaseous oxygen and mixture of methane and propane. The main idea of the experiment is that the mixing mechanism is considered as a dominant factor significantly affecting combustion instability in a fullscale thrust chamber. A single split triplet injector has been used with an open-end cylindrical combustion chamber. The characteristics revealed by excited dynamic pressures in gaseous combustion show degrees of relative acoustic damping depending on operating conditions. Upon test results, the direct comparison between various types of injectors can be realized for the selection of the best design among prospective injectors.

• Korean Journal of Human Ecology
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• v.24 no.4
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• pp.463-476
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• 2015

The purpose of this study was to examine the effects of paternal parenting sense of competence, paternal satisfaction, conflict-coping behaviors, and preschooler's emotional regulation on preschooler's social skills. Participants were 85 5- to 6-year-old preschoolers(41 boys, 44 girls) and their fathers. The Social Skill Rating Scale(Suh, 2004), the Parenting Sense of Competence(Shin & Chung, 1998), the Parental Satisfaction Scale(Seo & Lee, 2002), Conflict-coping behaviors(Cho & Kim, 2000) and the Emotional regulation(Kim & Kim, 1999) were used. Collected data were analyzed by descriptive statistics, t-test, correlation analysis and multiple regression analysis. The major findings were summarized as follows: (1) there were no differences between the boys' and girls' social skills. (2) parental satisfaction and emotional regulation explained social skills - cooperation. (3) conflict-coping behaviors(rationality and request for others) and emotional regulation explained social skills - self-control. (4) emotional regulation explained social skills - assertion. In conclusion, parental satisfaction, conflict-coping behaviors, and preschooler's emotional regulation influence differently according to the subscale of preschooler's social skills.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.346-350
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• 2005

Effects of the changes of a film cooling mass flow rate and operating conditions on the heat flux characteristics of the subscale calorimeter were studied. A film cooling ring with twelve orifices is inserted between the injector head and the calorimeter. The calorimeter is composed of nineteen cooling channels. When a mass flow rate of film cooling is 10.5 % of a main fuel mass flow rate, maximum heat flux at the nozzle throat is decreased by 30% compared to that without film cooling. In the OD3(of-design point) test result, maximum heat flux at the nozzle throat is increased by 31% compared to that of the DP(design point) test when a film cooling flow rate is zero.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.85-94
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• 2004

Experimental study on combustion characteristics of double swirl coaxial injectors has been conducted for the assessment of critical injector design parameters. A reusable, unielement thrust chamber has been fabricated with a water-cooled copper nozzle. Two principal design parameters. a swirl angle and a recess length, have been investigated through hot firing tests for the understanding of their effects on high pressure combustion. Clearly, both parameters considerably affect the combustion efficiency, dynamics and hydraulic characteristics of an injector. Internal mixing of propellants in a recess region increases combustion efficiency along with the increase of a pressure drop required for flowing the same amount of mass flow rates. It is concluded that pressure buildup due to flame can be released by the increase of LOx flow axial momentum or the reduction of a recess length. Dynamic pressure measurements of the thrust chamber show varied dynamic behaviors depending on injector configurations.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.61-68
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• 2015

Reactive sprays of two propellant combinations(GOx/kerosene and $GN_2O$/ethanol) were observed and compared with each other as a basic research of visualizing supercritical combustion. A shadowgraph imaging method was used to visualize the reactive sprays, and shadowgraph images were converted to density gradient magnitude images to analyse the structure of reactive sprays. The gas-liquid interface of GOx/kerosene spray showed rougher boundary and steeper density gradient near the injector face than the $N_2O$/ethanol at similar combustion chamber pressure. Spray core length was calculated from averaged density gradient magnitude images and it was revealed that spray core length of GOx/kerosene was shorter than that of $GN_2O$/ethanol, although momentum flux ratio of GOx/kerosene propellant combination was lower.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1435-1440
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• 2014

Background: It has been found that support given to women with breast cancer has a positive effect upon their reactions to the illness and may even prolong their survival. Perceived support needs assessment in breast cancer women could be considered as a necessary part of nursing function. Aim: The purpose of this study was to translate and culturally adapt the self-assessed support needs (SASN) questionnaire into Persian language and to investigate its psychometric properties. Materials and Methods: After forward-backward translation of the questionnaire and making appropriate changes, we selected 160 women with breast cancer as our study sample. The psychometric properties of the SASN, including its internal consistency, test retest reliability, and construct validity were evaluated through the known-groups technique. Results: The calculated Kaiser Meyer Olkin was 0.756, indicating that the sample was sufficiently large to perform a satisfactory factor analysis. The six factors all together explained 50.7% of the variance; the first factor (diagnosing) explaining the biggest part of variance (10.9). Internal consistency reliability was 0.83 for the whole scale and the stability of test was 0.78. For the first factor, Cronbach's alpha was 0.90 and factor loadings of scale's items were found to deal with diagnosis subscale. The domains described patients' diagnosis, treatment, support, femininity and body image, family and friends and information. Conclusions: The reliability and validity of the adapted version of the SASN was shown to be satisfactory. Thus, it can be used to investigate self-assessed support needs of Iranian women suffering from breast cancer since the SASN is a multi-domain scale.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.395-402
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• 2010

Baffle injectors are protruded into the combustion chamber and form an anti-pulsating baffle to prevent high-frequency combustion instabilities in transverse modes. Being exposed to a high heat-flux environment, the baffle injector has self-cooling passages through which kerosene is convected and heated. The baffle injector with 20 spiral cooling channels has been developed and successfully applied to 30 $ton_f$-class combustors without any performance loss due to an additional cooling. In this work, numerical analysis of conjugate heat transfer in baffle injectors with various cooling channel designs has been performed in order to reduce the fabrication cost which would be considerably increased for the 75 $ton_f$-class combustor. Prior to the application to a full-scale combustor, the thermal durability of the modified design has been verified through the subscale hot-firing tests.

• Journal of Acupuncture Research
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• v.37 no.4
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• pp.209-223
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• 2020

The purpose of this study was to evaluate the effectiveness of acupuncture treatment for the symptoms of Alzheimer's disease (AD). There were 11 databases searched for randomized controlled trials using acupuncture treatment for AD. The risk-of-bias assessment tool of the Cochrane Library was used to evaluate the quality of each study. Using the Review Manager (RevMan), a meta-analysis was performed using risk ratio, mean difference, 95% confidence interval, and random effect model. There were 32 studies selected, all of which were conducted in China. There were 16 studies where acupuncture was used as the intervention, and 23 studies used Donepezil as the control group. Acupoint GV20 was most frequently selected during the treatment. The Mini Mental State Examination (MMSE) was the most frequently used outcome variable. A period of 12 weeks was the most common treatment duration. As a result of meta-analysis (n = 25), acupuncture improved the MMSE and activities of daily living scores. Electroacupuncture improved the Alzheimer Disease Assessment Scale-Cognitive Subscale, and scalp acupuncture improved the MMSE score for AD. Acupuncture alleviates the symptoms of AD. However, further research is necessary to provide a better level of evidence.

• Journal of Korean Academy of Nursing
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• v.48 no.3
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• pp.375-388
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• 2018

Purpose: This study was conducted to assess the reliability and validity of the Korean version of the Coping and Adaptation Processing Scale-Short- Form in patients with cancer. Methods: The original scale was translated into Korean using Brislin's translation model. The Korean Short-Form and the Functional Assessment Cancer Therapy-General were administered to 164 Korean patients with cancer using convenience sampling method. The collected data were analyzed using SPSS 23.0 and AMOS 23.0. Construct validity, criterion validity, test-retest reliability, and internal consistency reliability of the Korean Coping and Adaptation Processing Scale-Short-Form were evaluated. Results: Exploratory factor analysis supported the construct validity with a four-factor solution that explained 60.6% of the total variance. Factor loadings of the 15 items on the four subscales ranged .52~.86. The four-subscale model was validated by confirmatory factor analysis (Normed ${\chi}^2=1.38$ (p=.013), GFI=.92, SRMR=.02, RMSEA=.05, TLI=.94, and CFI=.95), and criterion validity was demonstrated with the Functional Assessment Cancer Therapy-General. Cronbach's alpha for internal consistency of the total scale was .83 and ranged .68~.81 for all subscales, demonstrating sufficient test-retest reliability. Conclusion: The Korean version showed satisfactory construct and criterion validity, as well as internal consistency and test-retest reliability.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.333-340
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• 2013

Background: The aim of the study was to identify the relationship between 'Health Belief Model Scale for Cervical Cancer and the Pap Smear Test' subscale scores and demographic/gyneco-obstetric characteristics. Materials and Methods: This cross-sectional study was conducted with 256 women. Data were obtained using the 'Demographic and Gyneco-Obstetric Identification Form' and the 'Health Belief Model Scale for Cervical Cancer and the Pap Smear Test. Results: The percentage of women who had heard about the Pap test was 77.7 whereas only 32.4% had actually undergone the test. Some 45.7% of the women stated that they did not know the reason for having a Pap test. Women who had obtained a Pap smear test had statistically significantly fewer perceived barriers than those who had never had (p<0.05). Scores with regard to the subscales including 'Benefits of Pap Smear Tests and Health Motivation', 'Perceived Seriousness of Cervical Cancer', 'Susceptibility to Cervical Cancer' and 'Cervical Cancer Health Motivation' did not differ with demographic/gyneco-obstetric characteristics such as womens' educational level, whether or not young age at first marriage, whether or not having family history of female cancer, and whether or not having had a Pap test (p>0.05). Conclusions: Increasing knowledge about benefits of Pap smear tests, increasing motivation to obtain Pap Smear Test and increasing perceived seriousness of cervical cancer could promote attendance at cervical cancer screening. Different strategies are needed for behavioural change. Implementation of educational programmes by nurses in a busy environment could result in a major clinical change, based on the findings of this study.