• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1702-1710
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• 2001

Supersonic coaxial jets are investigated numerically by using the axisymmetric, Wavier-Stokes equations which are solved using a fully implicit finite volume method. Three different kinds of coaxial nozzles are employed to understand the flow physics involved in the supersonic coaxial jets. Two convergent-divergent supersonic nozzles are designed to have the same Mach number 2.0, and used to compare the coaxial jet flows with those discharging from one constant-area nozzle. The impingement angle of the annular jets are varied. The primary pressure ratio is changed in the range from 2.0 to 10.0 and the assistant jet ratio from 1.0 to 3.0. The results obtained show that the fluctuations of the total pressure and Mach number along the jet axis are much higher in the constant-area nozzle than those in the convergent-divergent nozzles, and the constant-area nozzle lead to higher total pressure losses, compared with the convergent-divergent nozzles. The assistant jets from the annular nozzle affect the coaxial jet flows within the distance less than about ten times the nozzle throat diameter, but beyond it the coaxial jet is conical with self-similar velocity profiles. Increasing both the primary jet pressure ratio and the assistant jet pressure ratio produces a longer coaxial jet core.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.28 no.2
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• pp.115-124
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• 2024

To compare the outcomes of low central venous pressure (CVP) to standard CVP during laparoscopic liver resection. The study design was a systematic review following the PRISMA statement standards. The available literature was searched to identify all studies comparing low CVP with standard CVP in patients undergoing laparoscopic liver resection. The outcomes included intraoperative blood loss (primary outcome), need for blood transfusion, mean arterial pressure, operative time, Pringle time, and total complications. Random-effects modelling was applied for analyses. Type I and type II errors were assessed by trial sequential analysis (TSA). A total of 8 studies including 682 patients were included (low CVP group, 342; standard CVP group, 340). Low CVP reduced intraoperative blood loss during laparoscopic liver resection (mean difference [MD], -193.49 mL; 95% confidence interval [CI], -339.86 to -47.12; p = 0.01). However, low CVP did not have any effect on blood transfusion requirement (odds ratio [OR], 0.54; 95% CI, 0.28-1.03; p = 0.06), mean arterial pressure (MD, -1.55 mm Hg; 95% CI, -3.85-0.75; p = 0.19), Pringle time (MD, -0.99 minutes; 95% CI, -5.82-3.84; p = 0.69), operative time (MD, -16.38 minutes; 95% CI, -36.68-3.39; p = 0.11), or total complications (OR, 1.92; 95% CI, 0.97-3.80; p = 0.06). TSA suggested that the meta-analysis for the primary outcome was not subject to type I or II errors. Low CVP may reduce intraoperative blood loss during laparoscopic liver resection (moderate certainty); however, this may not translate into shorter operative time, shorter Pringle time, or less need for blood transfusion. Randomized controlled trials with larger sample sizes will provide more robust evidence.

• Journal of computational fluids engineering
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• v.20 no.2
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• pp.73-80
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• 2015

Delayed Detached-Eddy Simulation was conducted to investigate surface pressure coefficient distribution and surface pressure fluctuation over an ONERA 70-degree delta wing at a high angle of attack. Time-averaged surface pressure distribution is directly affected by the primary vortices, whereas the pressure fluctuation is influenced by the unsteady fluctuating boundary layer over the surface. And pressure coefficient, velocity, pressure fluctuation, and turbulent kinetic energy were analyzed along the vortex core in order to investigate the process of vortex breakdown. Consequently, strong pressure fluctuations were found where the vortex breakdown was occurred at x~620 mm. The turbulent kinetic energy abruptly increased and followed after the vortex breakdown.

• Journal of Korean Academy of Nursing
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• v.8 no.1
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• pp.163-180
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• 1978

Much of a person's energy is spent in the effort of becoming a productive member of to-day's complex society. This activity may cause tension, and chronic unrelieved tension is an influential factor in blood pressure elevation. The problem of this study was to identify manifest needs and self-actualization of patients with essential hypertension, and to analyse and compare their manifest needs and selt-actualization with the selected general characteristics of We, sex, religion, occupation and level of education with a control group of patients with normal blood pressure readings. The purpose was to contribute to the planning of nursing interventions toward reducing the impact of complex psycho-somatic factors on the anxiety of patients with essential hypertension. The instruments used included selected items from the Edwards (1959) Personal Preference Schedule (EPPS) as adapted by Hwang (1965) and from the Personal Orientation Inventory (POI) (Shostrom 1964, 1974) adapted by Kim and Lee (1977) to measure manifest needs and self-actualization. The convenience sample was chosen from 149 persons who presented themselves for general physical examinations at Ewha University Medical Centre and 41 patients diagnosed with essential hypertension at three general hospitals in Seoul during June 1 and August 31, 1977. Forty-nine persons from the Ewha group with blood-pressure readings exceeding 150/90 were added to the experimental group. Data were analysed by the S.P.S.S. computer programme using t-test and tests for statistical significance. Statistically significant findings were as follows: A. Blood Pressure and Manifest Needs. 1. with the exception of Autonomy, patients with hypertension had significantly high scores on all variables Abasement, Achievement, Affiliation, Aggression, Dominance, Emotionality, Exhibitionism and Sex. 2. When mean scores of normal persons were compared by age groups, normal persons had higher scores in the following order on Abasement (50's, 40's, 20's, 30's), Achievement (50's, 30's, 40's, 20's), Affiliation (50's, 40's, 30's, 20's), Dominance (50's, 40's, 40's, 20's) and Exhibitionism (30's, 50's, 40's, 20's). In each case, there was a significant difference between the first and last age group scores. 3. When the mean scores of normal persons were compared by sex, normal men had higher scores than women on Achievement, Affiliation, Aggression, Dominance, Exhibitionism and Sex. Male patients had higher scores than female patients on Achievement, Dominance, Exhibitionism and Sex, but female patients scored higher in Emotionality. 4. Normal persons had higher scores related to religion in the following order on Achievement (Buddhism, no religion, Christianity). Hyper tensive patients had higher scores on. Exhibitionism (no religion, Christianity, Buddhism). 5. Normal persons had higher scores related to occupation in the following order on Achievement and Exhibitionism (unemployed, office workers, teachless, businessmen), Emotionality (office workers, unemployed, businessmen, teacher) and Sex (office workers, unemployed, teachers, businessmen). Hypertensive patients had higher scores on Achievement and Aggression (teachers, businessmen, office worker, unemployed), Dominance and Exhibitionism (businessmen, teacher, of ace workers, unemployed) and Sex (teachers, office worker, businessmen, unemployed). 6. Normal persons had higher scores related to level of edification in the following order on Abasement, Emotionality and Autonomy (secondary school graduation, university). Hypertensive patients had higher scores on Abasement (no education, primary, university, secondary), Achievement (no education, secondary, university, primary) , Dominance (university, no education, secondary, primary), Exhibitionism (university, secondary, no education, primary), and Sex (university, secondary, primary, no education). B. Blood Pressure and Self_Actualization 1, Patients with hypertension had significantly lower scores on all variables. 2. Normal persons had higher scores related to age groups in the following order on Existentiality (20's, 30's, 40's, 50's). Hypertensive patients showed no significantly different scores. 3. Normal women had higher scores than men on Time Competence. Normal men had higher scores on Feeling Reactivity. Male patients had higher scores than women on Self-Actualizing Value and Self-Regard. 4. Normal persons ha 1 higher scores related to religion on spontaneity (Buddhism, no religion, Christianity). Hypertensive patients had higher scores on Time Competence and Nature of Man (Buddhism, Christianity, no religion). 5. Normal persons had higher scores related to occupation in the following order on Existentiality (teachers, office workers, businessmen, unemployed) and Self-Regard (unemployed, office workers, teachers, businessmen). Hypertensive patients showed no significantly different scores. 6. Normal persons had higher scores related to level of education in the following order on Existentiality and Self-Acceptance (university, secondary). Hypertensive patients had higher scores on inner-Director (university, secondary, no education, primary) and Existentiality (university, secondary, primary, no education). Recommendations for nursing interventions with hypertensive patients with emotional problems or low self-actualization were made. 1. The nurse should encourage the patient through her interactions with other members of the medical team to accept counselling and health education. 2. Through her therapeutic interpersonal relationships with the patient, the nurse should help him discover the causes of his emotional tension. 3. Through her health teaching with the family, the nurse should encourage them to participate with the medical team in the patient's therapeutic plan and in providing him with the minimum possible emotional support. 4. Through frequent counselling with the obsessive-thinking and inflexible patient, the nurse should reevaluate the patient's behaviour and her interventions. 5. Seriously ill patients should be given needed reeducation by members of the professional medical team.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.2
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• pp.20-27
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• 2010

In order to prevent the corrosion of component contacted primary water designed alloy 600 material in the nuclear power plant. But the primary water stress corrosion cracking(PWSCC) of alloy 600 and weld area occurs continuously due to the residual stress. The leakage accident resulted from PWSCC in the drain nozzle of the steam generator of domestic power plants. Heater sleeves of the pressurizer are welded with alloy 600 weld material and therefore exposed to the primary water environment. PWSCC occurred in heater sleeve material and weld area of many foreign power plants. The current issue of domestic nuclear power plants are consequently concentrated to PWSCC of similar material. In order to improve the detection and the sizing of the PWSCC in the welding sleeve of the pressurizer, the automatic UT system and multi-directions probe sets have been developed. The experimental studies have been performed using the mock-up block containing artificial reflectors(ID connected EDM notch) and semi-artificial cracks made from thermal fatigue. The automatic UT System is applied in the detection and the length sizing of the ID/OD on the tube and the J-groove weld area of the artificial reflectors and results of the detection and the sizing are compared respectively. Also, the developed automatic UT system is successfully accomplished to inspect the heater sleeve and the J-groove weld area on the pressurizer for the detection of PWSCC.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.680-685
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• 2008

The ejector is a simple device which can transport a low-pressure secondary flow by using a high-pressure primary flow. In general, it consists of a primary driving nozzle, a mixing section, and a diffuser. The ejector system entrains the secondary flow through a shear action generated by the primary jet. Until now, a large number of researches have been made to design and evaluate the ejector systems, where it is assumed that the ejector system has an infinite secondary chamber which can supply mass infinitely. However, in almost all of the practical applications, the ejector system has a finite secondary chamber implying steady flow can be possible only after the flow inside ejector has reached an equilibrium state after the starting process. To the authors' best knowledge, there are no reports on the starting characteristics of the ejector systems and none of the works to date discloses the detailed flow process until the secondary chamber flow reaches an equilibrium state. The objective of the present study is to investigate the starting process of an ejector-diffuser system. The present study is also planned to identify the operating range of ejector-diffuser systems where the steady flow assumption can be applied without uncertainty. The results obtained show that the one and only condition in which an infinite mass entrainment is possible is the generation of a recirculation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium at this point.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.4
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• pp.605-615
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• 2000

This study was carried out to investigate sound characteristics including sound parameters and subjective sensation, and primary hand values related with sound of fabrics for blouse, and furthermore to predict subjective sound sensation with mechanical properties and sound parameters. Sound of specimens was analyzed by FFT. Level pressure of total sound(LPT), loudness(Z), coefficients of autoregressive(AR) functions for fitting the spectra, and sound color factors(ΔL and Δf) were obtained as sound parameters. Primary hand values for women's thin dress were calculated by using KES-FB. Subjective sensation for sound including softness, loudness, sharpness, clearness, roughness, highness, and pleasantness was evaluated by free modulus magnitude estimation. The results were as follows; 1. Fabrics for blouse showed similar spectral shapes to one another in that amplitude values were lower in most ranges of frequencies than fabrics for other uses. 2. It was found that fabrics for blouse were less louder because LPT, loudness(Z), and ARC values were lower than other fabrics. 3. Primary hand values indicated that specimens were soft-touched, flexible, and less crisp. Among primary hands related with sound, Shari values were higher for silk fabrics than for synthetic ones, while the values for Kishimi were similar, 4. Fabrics for blouse were rated more highly for softness, clearness, and pleasantness than for loudness, sharpness. roughness, and highness. Silk fabrics were evaluated more pleasant than synthetic fabrics. 5. Subjective sensation for sound of blouse fabrics were predicted with mechanical properties and physical sound parameters.

• Nuclear Engineering and Technology
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• v.35 no.5
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• pp.497-505
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• 2003

This paper describes a computational approach to the quantification of primary damage under irradiation and demonstrates the effect of neutron energy spectra on the formation of the displacement cascade. The development of displacement cascades in ${\alpha}-Iron$ has been simulated using the MOLDY code - a molecular dynamics code for simulating radiation damage. The primary knock-on atom energy, key input to the MOLDY code, was determined from the SPECTER code calculation on two neutron spectra. The two neutron spectra include; (i) neutron spectrum in the instrumented irradiation capsule of the high-flux advanced neutron application reactor (HANARO), and (ii) neutron spectrum at the inner surface of the reactor pressure vessel steel for the Younggwang nuclear power plant No.5 (YG 5). Minor differences in the normalized neutron spectra between the two spectra produce similar values of PKA energy, which are 4.7 keV for HANARO and 5.3 keV for YG 5. This similarity implies that primary damage to the components of the commercial nuclear reactors should be well simulated by irradiation in the HANARO. Moreover, the application of the MD calculations corroborates this statement by comparing cascades simulation results.

• Corrosion Science and Technology
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• v.18 no.1
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• pp.33-38
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• 2019

Alloy 600/182 with excellent mechanical/chemical properties have been utilized for nuclear power plants. Although both alloys are known to have superior corrosion resistance, stress corrosion cracking failure has been an issue in primary water environment of nuclear power plants. Therefore, primary water stress corrosion crack (PWSCC) growth rate tests were conducted to investigate crack growth properties of Alloy 600/182. To investigate PWSCC growth rate, test facilities including water chemistry loop, autoclave, and loading system were constructed. In PWSCC crack growth rate tests, half compact-tension specimens were manufactured. These specimens were then placed inside of the autoclave connected to the loop to provide primary water environment. Tested conditions were set at temperature of $360^{\circ}C$ and pressure of 20MPa. Real time crack growth rates of specimens inside the autoclave were measured by Direct Current potential drop (DCPD) method. To confirm inter-granular (IG) crack as a characteristic of PWSCC, fracture surfaces of tested specimens were observed by SEM. Finally, crack growth rate was derived in a specific stress intensity factor (K) range and similarity with overseas database was identified.

• Genomics & Informatics
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• v.20 no.3
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• pp.28.1-28.7
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• 2022

We described a clinical, laboratory, and genetic presentation of a pathogenic variant of the CYP1B1 gene through a report of a case of primary congenital glaucoma and a trio analysis of this candidate variant in the family with the Sanger sequencing method and eventually completed our study with the secondary/incidental findings. This study reports a rare case of primary congenital glaucoma, an 8-year-old female child with a negative family history of glaucoma and uncontrolled intraocular pressure. This case's whole-exome sequencing data analysis presents a homozygous pathogenic single nucleotide variant in the CYP1B1 gene (NM_000104:exon3:c.G1103A:p.R368H). At the same time, this pathogenic variant was obtained as a heterozygous state in her unaffected father but not her mother. The diagnosis was made based on molecular findings of whole-exome sequencing data analysis. Therefore, the clinical reports and bioinformatics findings supported the relation between the candidate pathogenic variant and the disease. However, it should not be forgotten that primary congenital glaucoma is not peculiar to the CYP1B1 gene. Since the chance of developing autosomal recessive disorders with low allele frequency and unrelated parents is extraordinary in offspring. However, further data analysis of whole-exome sequencing and Sanger sequencing method were applied to obtain the type of mutation and how it was carried to the offspring.