• 대한음성학회:학술대회논문집
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• 대한음성학회 2004년도 춘계 학술대회 발표논문집
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• pp.199-204
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• 2004

The purpose of this paper is to find prosodic characteristics in voice imitation. Speakers change various phonetic features in voice imitation. Speakers change their pitch ranges in the most cases. Especially, the pitch range is important for word conditions. And, as imitators change the voice, the average value of f0 is close to high frequence than low frequence or middle level.

• 한국전기전자재료학회논문지
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• 제16권11호
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• pp.975-978
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• 2003

The microwave dielectric properties and the microstructures on B $i_{0.97}$T $m_{0.03}$Nb $O_4$ doped with $V_2$ $O_{5}$ were systematically investigated. B $i_{0.97}$T $m_{0.03}$Nb $O_4$ ceramics sintered at 920-96$0^{\circ}C$ were mainly consisted of orthorhombic and triclinic phases after addition of $V_2$ $O_{5}$. The apparent density increased slightly with increasing the $V_2$ $O_{5}$ addition. The dielectric constants($\varepsilon$$_{r}$) also increased with $V_2$ $O_{5}$ addition(30-45). The Q${\times}$ $f_{0}$ values measured on B $i_{0.97}$T $m_{0.03}$Nb $O_4$ ceramics doped with $V_2$ $O_{5}$ were between 2,000 and 12,000[GHz] when the sintering temperatures were in the range of 920-960[$^{\circ}C$]. It was confirmed that the temperature coefficient of the resonant frequency($\tau$$_{f}$) can be adjusted from a positive value of +10ppm/$^{\circ}C$ to a negative value of -15ppm/$^{\circ}C$ by increasing the amount of $V_2$ $O_{5}$ Based on our experimental results, the B $i_{0.97}$T $m_{0.03}$Nb $O_4$(added $V_2$ $O_{5}$) ceramics can be applied to multilayer microwave devices at low sintering temperatures.ng temperatures.emperatures.ratures.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.350-353
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• 2002

The microwave dielectric properties and the microstructures on $Bi_{0.97}Nb_{0.03}O_{4}$doped with $V_{2}O_{5}$ were systematically investigated. $Bi_{0.97}Tm_{0.03}Nb_{0.03}O_{4}$ ceramics sintered at $920-960^{\circ}C$were mainly consisted of orthorhombic and triclinic phases after addition of $V_{2}O_{5}$. The apparent density increased slightly with increasing the $V_{2}O_{5}$ addition. The dielectric $constants(\varepsilon_r)$ also increased with $V_{2}O_{5}$ addition(30-45). The $Q{\times}f_0$ values measured on $Bi_{0.97}Tm_{0.03}NbO_4$ ceramics doped with $V_{2}O_{5}$ were between 2,000 and 12,000[GHz] when the sintering temperatures are in the range of $920-960[^{\circ}C]$. It was confirmed the temperature coefficient of the resonant $frequency(\tau_f)$ can be adjusted from a positive value of $+10[ppm/^{\circ}C]$ to a negative value of $-15ppm/^{\circ}C$ by increasing the amount of $V_{2}O_{5}$. Based on our experimental results, the Bi0.97Tm0.03NbO4(added V2O5) ceramics can be applied to multilayer microwave devices at low sintering temperatures.

• 지역사회간호학회지
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• 제4권2호
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• pp.100-108
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• 1993

The purpose of this study was to identify the workers the Knowledge, Attitude, and Practice of industrial health care services. The study was conducted from Dec 10, 1992 to Jan 20, 1993. The data was collected from 849 workers in 56 companies in Busan City. The data was analyzed by using the mean, S.D>, T-test, ANOVA. The tool for measuring the degree of Knowledge, Attitude and Practice of industrial health care of workers was developed by community health nursing academy and the reliability an of the tool was 0.82810. The results were as follows : 1. The general characteristics of workers : Distribution of workers consisted of laborer(55.0%), office workers(45.0%), in an age range from 25-39(55.0%), male employees were(69.7%), married employees were(62.4%), the educational level with the highest percentage was high school graduates(54.2%). The present work force had a career for 7 years or more with an income of 300-700 thousand won monthly(43.2). 2. The degree of Knowledge Attitude and Practice about industrial health care services of workers : The total score of the Knowledge, Attitude, and Practice was 49.09 points out of a possible 80(mean Score=2.46) 1) The total score of the Knowledge was 15.73 points out of 24. (Mean score=2.62) The following are the Knowledge scores: The necessity examination of occupational disease was(3.34) The knowledge of occupational disease was (3.12) The knowledge of health education was(1.29) 2) b. The total score of the Attitude was 26.01 point out of 44(mean score=2.36) The following are the Attitude scores: The necessity of health education for health examination was (3.14). The importance of health examination was(3.08) The necessity of measurement for working environment was(2.99). The satisfaction of the content in the periodic health examination was low(1.81). 3) The total score of the Practice was 7.35 points out of 12(mean score=2.45) The following are the orders of Practice scores: The participation in health examination was higher than in health education(1.33). 3. The general characteristics and the degree of knowledge, Attitude, and Practice of workers of industrial health care. 1) The level of worker's knowledge was significantly related by working part(t=2.54 P=0.000), marital status(F=4.35 P=0.029), educational level(F=3.91 and P=0.020), monthly income(F=2.98 P=0.029) 2) There were no significant difference between the general characteristics and the attitude of workers. 3) The practice was significantly related with working part(T=2.52 P=0.012), sex(T=2.28 P=0.23), marital status(F=4.25 P=0.012), monthly income (F=2.76 P=0.034) 4) The total score had a significant difference with working part(T=2.39 P=0.017), sex (T=3.84 P=0.000), marital status (F=3.18 P=0.032). Educational level (F=3.20 P=0.033), and monthly income(F=3.05 P=0.022).

• Journal of Ecology and Environment
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• 제42권2호
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• pp.70-76
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• 2018

Background: Sasa borealis (Hack.) Makino, a clonal dwarf bamboo, is widespread in Korean forests. Although S. borealis is native to that country, its growth habit can cause considerable harm when occupying particular areas where it dominates and influences those forested communities. However, few reports have described the extent of its inhibitory effects on the vigor of co-existing plant species. Therefore, we investigated the distribution, abundance, and diversity of other plant species in the communities where this plant occurs in the east-central forests on the Korean Peninsula. Results: S. borealis was most commonly found at an elevational range of 800 to 1,200 m, on gentle, usually lower, and near valley northern slopes. Out of the 13 forest communities based on 447 forest stands that we surveyed, S. borealis was detected in eight communities, mostly where Quercus mongolica dominates. In particular, it was more common in late-successional mixed stands of Q. mongolica, other deciduous species, and the coniferous Abies holophylla. Because of their ability to expand rapidly in the forest, this plant covered more than 50% of the surface in most of our research plots. Species diversity declined significantly (F = 78.7, p = 0.000) as the abundance of S. borealis increased in the herb stratum. The same trend was noted for the total number of species (F = 18.1, p = 0.000) and species evenness (F = 91.5, p = 0.000). Conclusions: These findings clearly demonstrate that S. borealis is a weed pest and severely hinders species diversity. Authorities should be implementing various measures for ecological control to take advantage of declining chance after the recent synchronized massive flowering of S. borealis.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.223-227
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• 2006

하이브리드 추진 시스템에서의 산화제 종류에 따른 연소특성을 알아보기 위한 연구를 수행하였다. 산화제는 $GN_2O$와 GOX를 사용하고, 고체연료는 폴리에틸렌(PE)을 사용해 연소시험을 하였다. 산화제 종류에 따른 연소특성은 O/F 비에 따른 화염온도로 해석이 가능하였으며, $GN_2O$가 GOX보다 하이브리드 추진 시스템의 산화제로 효율이 좋음을 확인하였다 산화제의 유량은 직경이 다른 여러 개의 쵸킹 오리피스로 제어했고, 산화제 공급 유량범위는 $0.0138{\sim}0.0427kg/sec$ 이었다. 산화제 종류에 따른 연소특성을 표현하는 실험식은 고체연료의 질량유속으로 나타냈고, 이는 물질전달 수와 산화제의 질량유속으로 얻어진다.

• 한국표면공학회지
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• 제34권1호
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• pp.10-16
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• 2001

Recently plasma etching research has been focused on the metal surfaces in the nuclear industry. In this study, surface etching reaction of metallic Co and Mo, principal contaminants in the spent nuclear components, in CF$_4$/O$_2$, gas plasma has been experimentally investigated to look into the applicability and the effectiveness of the technique for the surface decontamination. Experimental variables are $CF_4$/$O_2$ ratio and substrate temperature between 29$0^{\circ}C$ and 38$0^{\circ}C$. Experimental results Show that the optimum gas composition is 80%CF$_4$-20%$O_2$ and the metallic Co and Mo are etched out well enough in the temperatures range. Cobalt starts to be etched above $350^{\circ}C$ and the etching rate increases with increasing substrate temperature. Maximum rate achieved at 38$0^{\circ}C$ under 220 W r.f. plasma power is 0.06 $\mu\textrm{m}$/min. On the other hand, the metallic Mo is etched easily even at low temperature and the reaction rate drastically increases as the substrate temperature goes up. Highest rate obtained under the same conditions is $1.9\mu\textrm{m}$/min. OES (Optical Emission Spectroscopy) analysis reveals that the intensities of F atom and CO molecule reach maximum at the optimum gas composition, which demonstrates that the principal reaction mechanism is fluorination and/or carbonyl reaction. It is confirmed, therefore, that dry processing technique using reactive plasma is quite feasible and applicable for the decontamination of surface-contaminated parts or equipments.

• 한국양식학회지
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• 제8권2호
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• pp.117-131
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• 1995

현행의 해산어류 종묘생산 방법을 개량하여 보다 효율적인 종묘의 사육방법을 개발하고자, 감성돔과 황점볼락의 자어를 재료로 각각 여름과 겨울에 있어 순환여과식과 유수식 사육시스템에 의한 사육실험을 실시하고, 사육수의 수질환경 및 어체의 성장과 생존율을 비교하였다. 1 감성돔 순환여과식 사육시스템의 수온은 기온에 따라 변화하는 경향을 보였고, 유수식보다 평균 $1.4^{\circ}C$ 높은 $23.6\~26.4^{\circ}C$의 범위를 나타냈다 순환여과식 사육시스템에서의 비중은 $1.0252\~l.0266$의 범위로 비교적 안정되었으나, 유수식에서는 그 변화폭이 컷다. 사육수의 pH는 유수식 사육시스템에서 자연해수와 비슷한 변화를 보인 반면, 순환여과식에서는 7.51까지 낮아졌다. 사육수의 $NH_4-N,\;NO_2-N,\;NO_3-N$및 $PO_4-P$의 양은 순환여과식에서 애우 높았고, $NO_2-N$과 $NO_3-N$은 각각 3.623 ppm, 7.207 ppm까지 상승하였다. 순환여과식과 유수식 사육시스템간에 있어 어체의 전장, 체고 및 체중의 성장에는 유의한 차이를 인정할 수 없었다. 두 시스템의 어체 생존을은 F4 $71.2\%,\;F8\;66.2\%,\;R4\;16.2\%$, 그리고 R8 $5.5\%$의 순으로, 순환여과식 사육시스템에서 높았다. 2. 황점볼락 순환여과식 사육시스템에서의 수온은 유수식보다 평균 $1.5^{\circ}C$ 높은 $9.8\~14.6^{\circ}C$의 범위였다. 비중은 두 시스템에서 $1.0253\~l.0270$의 범위로 안정되었으나, 순환여과식 사육시스템에서 약간 높은 분포를 보였다. pH는 두 시스템에서 자연해수에 가까운 $7.96\~8.64$ 범위로 유지되었으나, 순환여과식 사육시스템에서 다소 낮아지는 경향이었다. 순환여과식에서의 $NO_2-N$과 $NO_3-N$ 양은 각각 0.433ppm, 2.333 ppm까지 높아져 유수식에 비해 높은 편이었으나, $NH_4-N$ 양은 오히려 낮았다. 순환여과식 사육시스템에서 어체의 전장 및 체중의 성장은 유수식에 비해 유의하게 빨랐으나, 체고의 성장에는 유의차가 없었다. 두 시스템의 어체 생존율은 $F4\;67.6\%$ 및 $R4\;73.6\%$로 나타나, 서로 비슷하였다.

• 한국세라믹학회지
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• 제40권1호
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• pp.81-86
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• 2003

고상합성한 $CaTiO_3$와 $YAlO_3$의 혼합분말을 소결하여 조성에 따른 미세조직과 고주파 유전특성의 변화를 조사하였다. $CaTiO_3-YAlO_3$ 고용체의 고주파 유전특성은 조성에 민감하게 의존하였다. 최적의 유전특성은 $0.75CaTiO_3-0.25YAlO_3$를 $1500^{\circ}C$에서 3시간 소결하였을 때 유전율 47, 품질계수 35000. 공진주파수의 온도계수 +11 ppm/$^{\circ}C$이었다. 동일 조성을 저온에서 치밀화 시키기 위하여 $CaB_2O_4$를 첨가하였을때 $1200^{\circ}C$ 이상에서 완전 치밀화 되었으며. $1300^{\circ}C$에서 3시간 소결하였을 경우, 유전율 47, 품질계수 37000, 공진주파수의 온도계수 +17ppm/$^{\circ}C$로 유전특성의 저하 없이 저온에서 치밀한 소결체를 얻을 수 있었다. $CaB_2O_4$를 소결조제로 한 $CaTiO_3-YAlO_3$계 소결체는 5~7GHz에서 중간유전율과 높은 품질계수를 갖는 고주파용 유전재료로 활용이 기대된다.

• Carbon letters
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• 제9권2호
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• pp.121-126
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• 2008

High modulus pitch based carbon fibers (HM) were exposed to isothermal oxidation using tube furnace in carbon dioxide gas to study the oxidation kinetics under the temperature of $800-1100^{\circ}C$. The kinetic equation $f=1-{\exp}(-at^b)$ was introduced and the constant b was obtained in the range of 1.02~1.42. The oxidation kinetics were evaluated by the reaction-controlling regime (RCR) depending upon the apparent activation energies with the conversion increasing from 0.2 to 0.8. The activation energies decrease from 24.7 to 21.0 kcal/mole with the conversion increasing from 0.2 to 0.8, respectively. According to the RCR, the reaction was limited by more diffusion controlling regime for the HM fibers with the conversion increasing. Therefore, it seems that the oxidation which is under the diffusion controlling regime takes place continuously from the skin to the core of the fiber.