• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.134-137
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• 2007

The temporal evolution of wake behind a circular cylinder oscillating rotationally with a relatively high forcing frequency has been investigated experimentally using a dynamic PIV technique. Experiments were carried out with varying the frequency ratio $F_R\;(=f_f/f_n)$ in the range from 0.0 (stationary) to 1.6 at oscillation amplitude of ${\theta}_A=30^{\circ}$ and Reynolds number of $Re=4.14{\times}10^3$. Depending on the forcing condition ($F_R$), the flow was divided into three regimes; non-lock-on ($F_R=0.4$), transition ($F_R=0.8$, 1.6) and lock-on regimes ($F_R=1.0$) with markedly different flow structure in the near-wake region behind the cylinder. When the frequency ratio was less than 1.0 ($F_R{\le}1.0$), the rotational oscillatory motion of the cylinder decreased the length of the vortex formation region and enhanced the mutual interaction between large-scale vortices across the wake centerline. The entrainment of ambient fluid seemed to play an important role in controlling the near-wake flow and shear-layer instability. However, the flow characteristics changed markedly beyond the lock-on flow regime ($F_R=1.0$) due to high-frequency forcing. At $F_R=1.6$, the mutual interactions between the vortices shed from both sides of the cylinder were not so strong. Thereby, the flow entrainment and momentum transfer into the wake center region were reduced. In addition, the size of the large-scale vortices decreased since the lateral extent of the wake was suppressed.

• Asian Oncology Nursing
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• v.7 no.1
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• pp.36-46
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• 2007

Purpose: This study was designed to fine out the relationships among body image, self-esteem and health promotion behavior in mastectomy patients. Method: Data were obtained by self -reported questionnaires from 218 patients undergone mastectomy from September 1 to October 15, 2005. And data were analyzed using SPSS/PC WIN 12.0 program. For the statistical analysis of the date, frequency and percentage, mean and standard deviation, t-test, ANOVA and Scheffe test and Pearson's correlation coefficients were used. Result: The mean scores of the body image, self-esteem, and health promotion of the subjects were $41{\pm}7.40$ (range of scale : 17 to 68), $22.22{\pm}4.95$ range of scale : 10 to 40), and $130.45{\pm}23.99$ range of scale : 50 to 200), respectively. There were significant differences with the score of body image by the work type (F=4.018, p= .008), a number of child (F=3.069, p= .029), and participation with self help group program (t=68.177, p= .001). There were significant differences with the score of self-esteem by the type of religion (F=4.546, p= .002), work type (F=4.488, p= .004), post operation period (F=2.814, p= .026), and participation with self help group program (t=12.901, p= .001). There were significant differences with the score of the health promotion behavior by the type of religion (F=3.066, p= .018), economic state (F=11.765, p= .001), level of education (F=6.285, p= .001), operation site (F=.368, p=.027), family history (t=6.557, p= .011), and hope of breast reconstruction (t=7.025, p=.009). Relationship between body image and self-esteem showed moderate positive correlation (r=0.631, p= .001). The relationship between body image and health promotion behavior showed slightly positive correlation (r=0.257, p= .001). The relationship between self-esteem and health promotion behavior showed moderate positive correlation (r=0.431, p=.001). Conclusion: For the increasement of the health promotion behavior, it is needed to improve body image and self-esteem in mastectomy patients. And, It is needed to encourage to participate with self help group program in mastectomy patients.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1061-1066
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• 2006

This paper presents the electrical characteristics with manufacturing process and performance evaluation of high performance zinc oxide varistors. ZnO varistors were fabricated with typical ceramic production methods with different thickness and the structural and electrical characteristics of ZnO varistors were investigated. All varistors exhibited high density, which was in the range of $5.41{\sim}5.49g/cm^3$. In the electrical properties, the reference voltage increased in the range of $4.410{\sim}5.250kV$ with increasing their thickness and the residual voltage exhibited the same trends as the reference voltage. In the long duration current impulse withstand test, E-2 and F-1 samples failed at the two and four shots of impulse current, respectively, but E-1 and F-2 samples survived 18 shots during the test. Before and after this test, the variation ratio of residual voltage of E-1 and F-2 samples were -0.34 % and 0.05 %, respectively, which were in the acceptance range of 5 %. According to the results of tests, it is thought that if the fabrication process such as insulating coating, sintering condition, and soldering method is improved, these ZnO varistors would be possible to apply to the station class arresters in the near future.

• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.329-337
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• 1991

The Ni-MgO composites were prepared by coprecipitation of NiO-MgO solid solutions and their selective reduction in a hydrogen atmosphere. We report on the measurements of both ac conductivity $\sigma$ ($\omega$, f) and dielectric constant $textsc{k}$'($\omega$, f) for the Ni-MgO composites in the frequency range from 10 Hz to 10 MHz at room temperature. The frequency exponents of conductivity and dielectric constant, x and y, are found to be x=0.98$\pm$0.05 and y=0.05$\pm$0.01. These results are in good agreement with a general scaling relation $\chi$-y=1, although these values are different from the theoretical predications. The dielectric constant exponent ($textsc{k}$' f-fc -s) is found to be s=0.62$\pm$0.07 with estimated percolation threshold fc=0.20$\pm$0.02.

• East Asian mathematical journal
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• v.38 no.1
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• pp.13-20
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• 2022

We establish multiplicity results for positive solutions to the Schrödinger-type singular positone problem: -∆u + V (x)u = λf(u) in Ω, u = 0 on ∂Ω, where Ω is a bounded domain in ℝ^N, N > 2, λ is a positive parameter, V ∈ L^∞(Ω) and f : [0, ∞) → (0, ∞) is a continuous function. In particular, when f is sublinear at infinity we discuss the existence of at least three positive solutions for a certain range of λ. The proofs are mainly based on the sub- and supersolution method.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.459-461
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• 1990

Me performed an experiment about preionization electron number density of charge transfer type KrF excimer laser. At the total pressure of 1.8 and 2.2 atm with helium (He) buffer gas, the experimental range of the electron number density is 8-9 ${\times}$ 10 cm The distance between electrode and preionization pin is 15 mJ at charging voltage of 27kV,gas pressure of 2.2 atm,gas mixture of F /Kr/He = 0.3/396.7(%).

• Journal of Korean Academy of Nursing
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• v.36 no.1
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• pp.189-196
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• 2006

Purpose: The purpose of this research was to test the effects of ST35 & Sulan moxibustion on knee joint pain, range of motion, and discomfort during Activies of Daily Living (ADL) in elderly with knee joint pain. Method: A nonequivalent control group pre-post test research design was used. Thirty four elderly who had knee joint pain were studied. Of them, sixteen were in the experimental group and eighteen the control group. The instruments used for this study were NRS, goniometer, and a modified ADL questionnaire developed by Lee. Result: The pain scores of right & left knee joint after moxibustion were significantly different between the experimental group and the control group (Right: F=26.27, p=0.000, Left: F=20.77, p=0.000). Right and left knee ROM scores were significantly different between the experimental group and the control group after moxibustion (Right: F=10.74, p=0.003, Left: F=9.239, p=0.005). Discomfort during ADL scores were significantly different between the experimental group and the control group after moxibustion (F= 32.31, p=0.000). Conclusion: It is necessary that nurses provide the elderly with knee joint pain with moxibustion to reduce joint pain and to increase knee ROM as an alternative therapy.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.5
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• pp.397-403
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• 2003

Microwave dielectric properties of (1-x)ZnW $O_4$-xTi $O_2$ ceramic systems were investigated with calcination temperatures and Ti $O_2$ contents. The ZnW $O_4$ ceramic could be suitably sintered at 1075$^{\circ}C$ and showed the dielectric constant of 13.6, quality factor(Q$\times$ $f_{O}$value) of 22,000 and temperature coefficient of resonant frequency($\tau$$_{f}$) of -65$\pm$2ppm/$^{\circ}C$. Increasing the amount of Ti $O_2$ in the range of 0.25 to 0.45 mol, the dielectric constant and $\tau$$_{f}$ increased due to the role of Ti $O_2$ but the quality factor decreased due to the increase of phase boundaries. The 0.7ZnW $O_4$-0.3Ti $O_2$ ceramic showed the dielectric constant of 19.8, qualify factor(Q$\times$ $f_{0}$) of 20,000 and $\tau$$_{f}$ of -3$\pm$1ppm/$^{\circ}C$.>.EX>.>.>.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.849-853
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• 2021

PET images used in medical diagnoses are created using positron emitting radionuclides. The radiation used for imaging is generated at 0.511 MeV by p-annihilation. The CSDA range is the distance the particle radiation flew physically, and it is different from the range shown in PET images. This study proposes a novel method that uses radiological criteria to measure this range. The experiment was conducted by applying the MCNP6 simulation to positron emitting nuclides ¹⁸F, ¹¹C, ¹³N, and ¹⁵O. Radiological criteria were based on the location of the p-annihilation event, which is also the image signal. Results showed the radiological range of positrons to be 2.3, 3.9, 5.0, and 7.9 mm for ¹⁸F, ¹¹C, ¹³N, and ¹⁵O, respectively. The higher the positron energy, the larger its difference from the CSDA range. Positron emitting nuclide is being developed and studied as a nuclide for dosimetry or radiotherapy. Further research needs to be conducted into various positron ranges.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.4
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• pp.623-633
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• 2020

Objective: Substituting starch with digestible fiber (dF) can improve digestive health of rabbits and reduce costs. Therefore, it is necessary to develop a criterion for dF and starch supply. Effects of the dietary dF-to-starch ratio on pellet quality, growth and cecal microbiota of Angora rabbits were evaluated. Methods: Five isoenergetic and isoproteic diets with increasing dF/starch ratios (0.59, 0.66, 0.71, 1.05, and 1.44) were formulated. A total of 120 Angora rabbits with an average live weight of 2.19 kg were randomly divided into five groups with four replicates. At the end of 40 day feeding trial, cecal digesta were collected to analyse microbiota. Results: The results showed that the dF/starch ratio had linear effects on pellet variables (p<0.01). When the dF/starch ratio was 1.44, the pellets had the lowest powder and highest durability. The dF/starch ratio had unfavorable linear effects on growth variables (p<0.001). When analyzed by quadratic regression, the optimal dF/starch ratios for average weight gain and feed/gain were 0.59 and 0.74, respectively. There were differences in wool yield, fiber length and fiber diameter caused by the dF/starch ratio (p<0.05), and the dF/starch ratios that ranged from 0.66 to 1.06 were appropriate for good results. The cecal microbiota operational taxonomic unit (OTU) number index in the 1.05 dF/starch treatment was higher than that in the 0.66 and 0.71 dF/starch treatments. The higher dF/starch ratio resulted in a higher cecal microbiota OTU number index (p<0.05). The proportion of Ruminococcus in the 0.71 dF/starch treatment was higher than that in the 0.59 dF/starch treatment (p<0.05) Conclusion: The most suitable dF/starch ratio for feed pellet quality is 1.44, and for rabbit growth the optimal range of ratios is from 0.59 to 0.74. With combination of the wool growth, output cost, and cecal microbiota, we suggest that a dietary dF/starch ratio ranging from 0.74 to 1.06 is optimal.