• The korean journal of orthodontics
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• v.20 no.2
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• pp.381-390
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• 1990

The purpose of this study was to evaluate the effects of heat treatment on mechanical properties in $0.016^{{\prime}{\prime}}{\times}0.022^{{\prime}{\prime}}$ blue Elgiloy wires and to measure the amounts of nickel and chromium released from the wires in artificial saliva. Ultimate tensile strength, yield strength and elongation were measured with universal testing machine (Instron). and the amounts of nickel and chromium released from the sample were measured with atomic absorption spectrophotometer after one week immersion in the artificial saliva. Ultimate tensile strength and yield strength were progressively increased below $1000^{\circ}F$, but elongation was decreased. And the results were reversed above $1100^{\circ}F$. After heat treatment of the sample for 9 minutes at $1000^{\circ}F$, the maximum tensile strength and yield strength were $213.6kg/mm^2$, $140.1kg/mm^2$, respectively. Both tensile strength and yield strength were decreased progressively above $1100^{\circ}F$. Elongation was appeared the minimum value (8.6%) after heat treatment for 9 minutes and 12 minutes at $1000^{\circ}F$. There was a pronounced increase in nickel and chromium liberation with increasing time and temperature. The maximum amounts of nickel and chromium released form the sample were $4.947{\mu}m/cm^2$, $3.088{\mu}g/cm^2$, respectively after heat treatment for 12 minutes at $1300^{\circ}F$. Heat treatment is applied to orthodontic wires, especially cobalt-chromium alloys, for the purpose of stress-relievning and hardening. When the heat-treatment of orthodontic wires, the heating procedure should be well controlled in order to have no effect on corrosion resistance and mechanical properties.

• Research in Community and Public Health Nursing
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• v.10 no.1
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• pp.239-251
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• 1999

The purpose of this survey is to measure the sexual knowledge, attitude, and experience in college students in order to provide better sex education programs and direction. For this study, questionnaires were given to 259 students in K college of Kyongnam and collected during the period of June 1 to June 20, 1998. Data was analyzed using a statistical computer package: SPSS to manipulate the data along with frequency, mean, t-test, F-test and Pearson correlation coeffiency. The results from this study were summarized as follows: 1. Sex related knowledge marked 12.01 at a maximum level of 25. In the areas of Sex physiology(51.8%), genital physiology(49.9%), venereal diseases(44.3%) and contraceptive methods (38.1%), students were shown to have certain levels of knowledge. 2. Sex related attitudes marked 15.35 at a maximum level of 35. The most frank attitudes concerned 'premartial coitus in males' and the most conservative attitudes concerned 'extramarital coitus in females'. 3. Concerning sexual behavior 80.7% of the respondents had associated with the opposite sex. The most frequent behaviors were walking arm in arm (male : 28.6%, female: 36.2%). Their main problems were relationships with the opposite sex(male : 39.2%, female: 24.5%), frustrated sexual desire(male : 26.0%, female: 9.8%) and unwanted pregnacy(male: 15.2%, female: 7.8%) To solve sex problems, respondents intended to consult their friends(male : 35.7%, female: 46. 7%) and become active in sports or recreation (male: 23.4%, female: 11.4%). About 81.2% of male students had a masturbation experience, but only 11.4% of female did, 40.0% of male students had a sexual intercourse experience, but only 13.3% of females did, 7.8% of male students used contraceptive methods, but only 2.9% of females did. 12.3% of male students had a rape experience, but only 10.5% of females did. The proportion of male students who made someone pregnant was 12.3%,however pregnant female were only 6.8% and the proportion of male students who forced someone to have an abortion was 12.3%, females who experienced an abortion were only 5.7%. 4. Regarding genital physiology, there was a statistically significant differences in gender ( t = -7.342, p=0.000). Regarding contraceptive methods, there was a statistically significant difference in the father's education level(F= 2.421, p=0.036) 5. In sexual attitudes, there were statistically significant differences in gender( t = 4.456, p = 0.000), religion(F=4.315, p=0.000), high school(F=3.150, p=0.045), habitation form(F= 3.164, p=0.0025 and methods of acquiring sexual knowledge(F=2.990, p=0.012). 6. The variables regarding sexual experience were gender, high school, economic status, habitation form, method of acquiring sexual knowledge, and parental attitudes toward sex. From the result of the study, sex education is required and must be taught as a regular course in the curriculum of all Korean schools at all levels.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.1
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• pp.41-48
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• 1998

An investigation made of the easing contraction ratio according to sewing conditions (eased seam angle; 0$^{\circ}$ 20$^{\circ}$ 30$^{\circ}$ 45$^{\circ}$ 60$^{\circ}$ 70$^{\circ}$ 90$^{\circ}$, stitch density; 38 stitches/3 cm(N1.0), 26 stitches/ 3 cm(N1.5), 19 stitches/3 cm(N2.0), 14 stitches/3 cm(N2.5), 12 stitches/3 cm(N3.0), thread; sp 60' s/2) by lockstitch industrial sewing machine with shirring foot. The results abstained were as follows: 1. The lower the stitch density , the higher the easing contraction ratio. 2. The easing contraction ratio at 0$^{\circ}$ and 90$^{\circ}$ were lower than bias angles (20$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$, 70$^{\circ}$). 3. As the results of visual test, the maximum easing conditions were Fl -0$^{\circ}$.20$^{\circ}$.30$^{\circ}$.45$^{\circ}$-12 stitches/3 cm(N3.0), 60$^{\circ}$. 70$^{\circ}$. 90$^{\circ}$-14 stitches/3 cm(N2.5), F2 -0$^{\circ}$. 20$^{\circ}$.30$^{\circ}$.60$^{\circ}$.70$^{\circ}$.90$^{\circ}$-19 stitches/ 3 cm(N2.0), 45$^{\circ}$ -14 stitches/3 cm(N2.5), and F3 -0$^{\circ}$.20$^{\circ}$.30$^{\circ}$.45$^{\circ}$.60$^{\circ}$.70$^{\circ}$.90$^{\circ}$-19 stitches/3 cm (N2.0). 4. Approximately easing contraction ratio was obtained as 2.0% (N1.0)~ 10.2% (N3.0) in F1, 6.7% (N1.0)~ 15.7% (N2.0) in F2, and 5.2% (N1.0)~ 12.1% (N2.0) in F3, according to different angles on the sleeve cap curve line. 5. As a resets of SPSS PC) statistics analysis, it confirmed the relations which were observed between easing contration ratio and stitch density, and easing contraction ratio was correlated with bending properties.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.18-23
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• 2000

In this paper, we propose the organic light-emitting devices with vacuum evaporated ultrathin CsF layer between the AI electrode and conjugated polymer MEH-PPV which was spin coated. In this structure, the CsF layer will be well transferred the electron injection from the electrode to the emission layer MEH-PPV. Finally this structure enhances the emission efficiency of the organic light-emitting device. And we measured the I-V-L properties with the split of CsF thickness into the $2{\AA},\;4{\AA},\;8{AA},\;10{\AA},\;20{\AA},\;50{\AA},\;75{AA}$ respectively. And also we evaporated CsF/Al, CsF/Au Cs/Au electrode respectively for the comparison. As the results, we obtained the maximum quantum efficiency 0.6% at $4{\AA}$ CsF thickness and then at $8{\AA}$, it decreased a little but it's still better than pure Al electrode which has 0.01%.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2124-2132
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• 1999

Given a graph G=(V,E), Ld(2,1)-labeling of G is a function f : V(G)$\longrightarrow$[0,$\infty$) such that, if v1,v2$\in$V are adjacent, $\mid$ f(x)-f(y) $\mid$$\geq$2d, and, if the distance between and is two, $\mid$ f(x)-f(y) $\mid$$\geq$d, where dG(,v2) is shortest distance between v1 and in G. The L(2,1)-labeling number (G) is the smallest number m such that G has an L(2,1)-labeling f with maximum m of f(v) for v$\in$V. This problem has been studied by Griggs, Yeh and Sakai for the various classes of graphs. In this paper, we discuss the upper-bound of ${\lambda}$ (G) for a chordal graph G and that of ${\lambda}$(G') for a permutation graph G'.

• Speech Sciences
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• v.12 no.4
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• pp.203-213
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• 2005

This study was conducted to investigate the respiratory and aerodynamic function of adductor spasmodic dysphonia (ADSD) patients. Participants were (1) 18 females SD patients with non- Botulinum toxin injection (2) 14 females SD patients who had taken treatment of Botulinum toxin injection. (3) 14 age- and sex- matched normal female controls. Spirometer and phonatory function analyzer were used for respiratory muscle pressure (MIP: Maximum inspiratory pressure), MEP: Maximum expiratory pressure)& MPT(Maximum phonation time) and aerodynamic(F0:Fundamental frequency, intensity, MFR: Mean flow late, Psub: Subglottal pressure) measurement. The results were as follows: (1) Normal group was significantly higher in MIP, MEP, MPT than two SD groups (p < .05); (2) MPT was significantly lower in SD with non-Botulinum toxin injection group than SD with the treatment experience of Botulinum toxin injection (p < .05); (3) All aerodynamic parameters, F0, intensity, MFR, Psub, were not significantly different among three groups(p > .05).The reason of short MPT in ADSD may use lower respiratory pressure than normal group as strategy to decrease their tremulous voice quality. Moreover respiratory muscle pressure was lower than normal group regardless of botulinum toxin injection treatment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.9
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• pp.598-601
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• 2015

The $Sr_{0.7}Bi_{2.3}Nb_2O_9(SBN)$ thin films are deposited on Pt electrode($Pt/Ti/SiO_2/Si$) using RF sputtering method at various deposition temperature. The deposition temperature of optimum was $300^{\circ}C$. SBN thin films were annealed at $500{\sim}700^{\circ}C$ using furnace and RTA, respectively. The surface roughness showed about 2.42 nm in annealing temperature($600^{\circ}C$) of furnace. The capacitance density of SBN thin films were increased with the increase of annealing temperature. The maximum capacitance density of $0.7{\mu}F/cm^2$ was obtained by annealing temperature($700^{\circ}C$). The frequency dependence of dielectric loss showed about 0.03 in frequency ranges of 1~1,000 kHz.

• Kyungpook Mathematical Journal
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• v.59 no.3
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• pp.515-523
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• 2019

Consider a graph G of order n and maximum degree ${\Delta}$. Let $f:V(G){\rightarrow}\{0,1,{\cdots},{\lceil}{\frac{{\Delta}}{2}}{\rceil}+1\}$ be a function that labels the vertices of G. Let $B_0=\{v{\in}V(G):f(v)=0\}$. The function f is a strong Roman dominating function for G if every $v{\in}B_0$ has a neighbor w such that $f(w){\geq}1+{\lceil}{\frac{1}{2}}{\mid}N(w){\cap}B_0{\mid}{\rceil}$. In this paper, we study the bounds on strong Roman domination numbers of the Cartesian product $P_m{\square}P_k$ of paths $P_m$ and paths $P_k$. We compute the exact values for the strong Roman domination number of the Cartesian product $P_2{\square}P_k$ and $P_3{\square}P_k$. We also show that the strong Roman domination number of the Cartesian product $P_4{\square}P_k$ is between ${\lceil}{\frac{1}{3}}(8k-{\lfloor}{\frac{k}{8}}{\rfloor}+1){\rceil}$ and ${\lceil}{\frac{8k}{3}}{\rceil}$ for $k{\geq}8$, and that both bounds are sharp bounds.

• Progress in Medical Physics
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• v.27 no.3
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• pp.156-161
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• 2016

When air discharged from a radioisotope production facility is contaminated with radiation, the public may be exposed to radiation. The objective of this study is to manage such radiation exposure. We measured the airborne radioactivity concentration at a 30 MeV cyclotron radioisotope production facility to assess whether the exhaust gas was contaminated. Additionally, we investigted the radioactive contamination of the air filter for efficient air purification and radiation safety control. To measure the airborne radiation concentration, specimens were collected weekly for 4 h after the beginning of the radioisotope production. Regarding the air purifier, five specimens were collected at different positions of each filter-pre-filter, high-efficiency particulate air filter, and charcoal filter-installed in the cyclotron production room. The concentrations of F-18, I-123, I-131, and Tl-201 generated in the radioiodine production room were $13.5Bq/m^3$, $27.0Bq/m^3$, $0.10Bq/m^3$, and $11.5Bq/m^3$, respectively; the concentrations of F-18, I-123, and I-131 produced in the radioisotope production room were $0.05Bq/m^3$, $16.1Bq/m^3$, and $0.45Bq/m^3$, correspondingly; and those of F-18, I-123, I-131, and Tl-201 generated in the accelerator room were $2.07Bq/m^3$, $53.0Bq/m^3$, $0.37Bq/m^3$, and $0.15Bq/m^3$, respectively. The maximum radiation concentration of I-123 generated in the radioiodine production room was 1,820 Bq/g, which can be disposed after 2 days. The maximum radiation concentration of Tl-202 generated in the radioisotope production room was 205 Bq/g, and this isotope must be stored for 53 days. The I-123 generated in the radioiodine production room had a maximum concentration of 1,530 Bq/g and must be stored for 2 days. The maximum radiation concentration of Na-22 generated in the radioisotope production room was 0.18 Bq/g and this isotope must be disposed after 827 days. To manage the exhaust, the efficiency of air purification must be enhanced by selecting an air purifier with a long life and determining the appropriate replacement time by examining the differential pressure through systematic measurements of the airborne radiation contamination level.

• Journal of Magnetics
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• v.8 no.2
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• pp.93-97
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• 2003

For the induction motor and inverter type motor design, prediction and analysis of core loss including higher harmonics have been studied. In this work, we have generated two symmetrical ac minor loop in the fundamental hysteresis loop whose positions are zero induction region and saturation induction region, and we could pre-dict core loss including higher harmonics inductions. using the following modified superposition principle; $P_c(B_0,f_0,B_h,nf_0)=P_c(B_0,f_0)+(n-1)[K_1(B_0)P_{cL}(B_h,nf_0)+(1-k_1(B_0))P_{cH}(B_h,nf_0)].$Using this equation we could also analyze core losses including higher harmonic induction under different maximum magnetic induction, different amplitude of higher harmonic induction with different harmonic frequencies.