• Journal of Magnetics
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• 제13권3호
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• pp.110-113
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• 2008

In this study, heavy rare earth garnet $Tb_2Bi_1Ga_1Fe_4O_{12}$ powders were fabricated by a sol-gel and vacuum annealing process. The crystal structure was found to be single-phase garnet with a space group of Ia3d. The lattice constant $a_0$ was determined to be 12.465 ${\AA}$. From the analysis of the vibrating sample magnetometer (VSM) hysteresis loop at room temperature, the saturation magnetization and coercivity of the sample are 7.64 emu/g and 229 Oe, respectively. The N$\acute{e}$el temperature($T_N$) was determined to be 525 K. The M$\ddot{o}$ssbauer spectrum of $Tb_2Bi_1Ga_1Fe_4O_{12}$ at room temperature consists of 2 sets of 6 Lorentzians, which is the pattern of single-phase garnet. From the results of the M$\ddot{o}$ssbauer spectrum at room temperature, the absorption area ratios of Fe ions on 24d and 16a sites are 74.7% and 25.3%(approximately 3:1), respectively. These results show that all of the non-magnetic Ga atoms occupy the 16a site by a vacuum annealing process. Absorption area ratios of Fe ions are dependent not only on a sintering condition but also on the temperature of the sample. It can then be interpreted that the Ga ion distribution is dependent on the temperature of the sample. The M$\ddot{o}$ssbauer measurement was carried out in order to investigate the atomic migration in $Tb_2Bi_1Ga_1Fe_4O_{12}$.

• 한국화재소방학회논문지
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• 제21권4호
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• pp.38-43
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• 2007

최근 우리나라 고층아파트에서 많은 문제가 되고 있는 승강장 부속실의 급기가압 시스템에 있어서 거주자의 피난 시나리오에 따른 차압의 변화 및 연기유동 특성을 FDS 화재모델링을 이용하여 현상학적으로 살펴보았다. 자동차압조절댐퍼의 기준압을 화재실로 할 경우 현관문 누설틈새를 통한 공기의 화재실 유입으로 화재실 및 부속실 모두 절대압이 크게 상승하는 결과를 가져왔으며 피난으로 계단실 방화문이 개방 후에는 다시 닫히지 않아 부속실내의 차압형성이 안 되는 문제점이 예상되었다. 따라서 화재실압이 지속적으로 상승하지 않도록 거실에 별도의 개구부가 필요한 것으로 판단된다. 현관문 개방 후 다시 닫힐 시에는 순간적으로 200 Pa 정도의 높은 과압이 형성되어 이 시간 동안에는 화재실 안의 또 다른 거주자가 현관문을 개방하기는 어려울 것으로 예상되었으며, 현관문만 개방 시에는 적정방연풍속이 유지되었으나, 현관문과 계단실 방화문이 동시에 개방되어 있을 경우에는 적정방연풍속이 생성되지 않아 부속실 및 계단실로의 연기유입이 발생하는 것으로 예측되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.96-96
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• 2007

Low voltage organic TFTs (OTFTs) and ZnO based TFTs (<5V), utilizing room temperature deposited $Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7$ (BZN) thin films were recently reported, pointing to high-k gate insulators as a promising route for realizing low voltage operating flexible electronics. $Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7$ (BZN) thin film is one of the most promising materials for gate insulator because of its large dielectric constant (~60) at room temperature. However their tendency to suffer from relatively high leakage current at low electric field (>0.3MV/cm) hinder the application of BZN thin films for gate insulator. In order to improve leakage current characteristics of BZN thin film, we mixed 30mol% MgO with 70mol% BZN and their dielectric and electric properties were characterized. We fabricated field-effect transistors with transparent oxide semiconductor ZnO serving as the electron channel and high-k $(Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7)_{0.7}(MgO)_{0.3}$ as the gate insulator. The devices exhibited low operation voltages (<4V) due to high capacitance of the $(Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7)_{0.7}(MgO)_{0.3}$ dielectric.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.643-648
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• 2014

The accelerated thermal aging of CSPE (chlorosulfonated polyethylene) was carried out for 40.41, 121.22, and 202.04 days at $100^{\circ}C$, which are equivalent to 20, 60, and 100years of aging at $50^{\circ}C$, respectively. The volume electrical resistivities of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were $1.107{\times}10^{14}-2.097{\times}10^{14}$, $7.752{\times}10^{13}-1.556{\times}10^{14}$, $7.693{\times}10^{13}-1.521{\times}10^{14}$, and $7.380{\times}10^{13}-1.304{\times}10^{14}{\Omega}{\cdot}cm$, respectively, at room temperature. The permittivities of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were $2.89{\times}10^{-11}-3.65{\times}10^{-11}$, $3.40{\times}10^{-11}-3.70{\times}10^{-11}$, $3.50{\times}10^{-11}-3.82{\times}10^{-11}$, and $3.76{\times}10^{-11}-4.13{\times}10^{-11}$ F/m, respectively, at room temperature. The EAB (elongation at break) of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were 98.8-101.3, 59.5-60.3, 37.8-39.2, and 41.8-44.3%, respectively, at room temperature. The apparent densities of the accelerated thermally aged CSPE samples for 0, 40.41, 121.22, and 202.04 days were 1.603-1.614, 1.611-1.613, 1.622-1.628, and $1.618-1.620g/cm^3$, respectively, at room temperature. The measured currents of the accelerated thermally aged CSPE and the standard sample were almost constant after 5 min of applying a 300-V/mm electric field to the CSPE. The V-I slope of the accelerated thermally aged CSPE sample was increased if the applied electric field was increased at room temperature, and the V-I slope of the accelerated thermally aged CSPE was higher than that of standard CSPE.

• 한국지반신소재학회논문집
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• 제21권4호
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• pp.21-29
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• 2022

주방식 공법(room-and-pillar method) 또는 격자형 지하공간은 굴착부를 일정한 간격으로 직교하도록 굴착하여 자연 암반을 구조체로 활용하여 공간을 형성해 나가는 공법을 말한다. 이러한 굴착은 굴착 방향과 순서에 따라 최대 변위가 발생하는 굴착 단계와 크기가 다르게 나타날 수 있다. 본 연구에서는 격자형 굴착공정의 최적 설계를 위하여 숏크리트 및 록볼트 등 지보재가 설치되는 것을 고려하여 특정 지반조건에서의 격자형 지하공간 설계 및 시공 시 안정성과 시공성을 해석적으로 검토하였다. 해석적 방법을 사용하여 지반조건을 설정하고 일정 상재하중 하에서 굴착단계와 시공 종류별로 암주 응력과 천단 변위를 확인하였다. 공간의 높이는 8m로 일반 사무실 크기보다 높게 설정하여 장비나 플랜트 시설을 감안하여 검토되었다. 또한, 숏크리트와 록볼트를 고려하여 지보재 설치에 따른 변위 제어의 정도를 검토하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
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• pp.77-77
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• 1998

Present silicon dioxide (SiOz) 떠m as intennetal dielectridIMD) layers will result in high parasitic c capacitance and crosstalk interference in 비gh density devices. Low dielectric materials such as f f1uorina뼈 silicon oxide(SiOF) and f1uoropolymer IMD layers have been tried to s이ve this problem. I In the SiOF ftlm, as fluorine concentration increases the dielectric constant of t뼈 film decreases but i it becomes unstable and wa않r absorptivity increases. The dielectric constant above 3.0 is obtain어 i in these ftlms. Fluoropolymers such as polyte$\sigma$따luoroethylene(PTFE) are known as low dielectric c constant (>2.0) materials. However, their $\alpha$)Or thermal stability and low adhesive fa$\pi$e have h hindered 야1리ru뚱 as IMD ma따"ials. 1 The concept of a plasma processing a찌Jaratus with 비gh density plasma at low pressure has r received much attention for deposition because films made in these plasma reactors have many a advantages such as go여 film quality and gap filling profile. High ion flux with low ion energy in m the high density plasma make the low contamination and go어 $\sigma$'Oss피lked ftlm. Especially the h helicon plasma reactor have attractive features for ftlm deposition 야~au똥 of i앙 high density plasma p production compared with other conventional type plasma soun:es. I In this pa야Jr, we present the results on the low dielectric constant fluorocarbonated-SiOF film d밑JOsited on p-Si(loo) 5 inch silicon substrates with 00% of 0dFTES gas mixture and 20% of Ar g gas in a helicon plasma reactor. High density 띠asma is generated in the conventional helicon p plasma soun:e with Nagoya type ill antenna, 5-15 MHz and 1 kW RF power, 700 Gauss of m magnetic field, and 1.5 mTorr of pressure. The electron density and temperature of the 0dFTES d discharge are measUI벼 by Langmuir probe. The relative density of radicals are measured by optic허 e emission spe따'Oscopy(OES). Chemical bonding structure 3I피 atomic concentration 따'C characterized u using fourier transform infrared(FTIR) s야3띠"Oscopy and X -ray photonelectron spl:’따'Oscopy (XPS). D Dielectric constant is measured using a metal insulator semiconductor (MIS;AVO.4 $\mu$ m thick f fIlmlp-SD s$\sigma$ucture. A chemical stoichiome$\sigma$y of 야Ie fluorocarbina$textsc{k}$영-SiOF film 따~si야영 at room temperature, which t the flow rate of Oz and FTES gas is Isccm and 6sccm, res야~tvely, is form려 야Ie SiouFo.36Co.14. A d dielec$\sigma$ic constant of this fIlm is 2.8, but the s$\alpha$'!Cimen at annealed 5OOt: is obtain려 3.24, and the s stepcoverage in the 0.4 $\mu$ m and 0.5 $\mu$ m pattern 킹'C above 92% and 91% without void, res야~tively. res야~tively.

• 한국화재소방학회논문지
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• 제23권3호
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• pp.85-92
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• 2009

본 논문은 차동식스포트형열감지기 현장점검용 표준화기기 개발에 관한 연구이다. 현재 소방점검 시 차동식스포트형열감지기의 성능확인을 위해 사용되는 점검기기(4 Type)들을 실험대상으로 선정하여 문제점을 찾고, 도출된 문제점을 바탕으로 차동식스포트형열감지기 형식승인 시 감도시험기준과 동일한 온도조건인 실온보다 $30^{\circ}C$ 높은 온도로 자동설정 할 수 있고 설정된 온도를 계속 유지할 수 있는 기능과 풍속 조건인 풍속 85cm/s를 유지할 수 있는 차동식스포트형열감지기 현장점검용 표준화기기의 회로를 설계하고 시제품을 제작하였다. 개발된 시제품의 성능확인 결과 차동식스포트형열감지기의 형식승인시험 시 감도시험조건과 동일한 성능이 나타나는 것을 확인하였다.

• 지구물리와물리탐사
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• 제21권4호
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• pp.220-230
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• 2018

상온 환경에서 PEDB (Portable Electronic Divided Bar) 시스템을 이용하여 암석의 열전도도를 측정할 경우 실내온도 변화에 영향을 받는다. 따라서 온도와 습도를 일정하게 조절할 수 있는 항온항습기 내에서 열전도도를 측정하면 상온 환경에서 측정할 때의 단점을 보완할 수 있다. 이 연구에서는 항온항습 상태에서 열전도도를 측정할 수 있는 시스템을 구축하여, 울릉도의 GH3, GH4 시추공에서 채취된 45개 시편에 대해 항온항습기 내에서 건조 및 수포화 열전도도를 측정하고 그 특성을 살펴보았다. 또한, 16개 시편에 대해 밀도 및 유효공극률을 측정하여 열전도도와의 상관관계를 분석하였다. 열전도도와 유효공극률 및 밀도의 상관성 분석결과, 수포화 시료보다는 건조시료에서 보다 높은 상관성을 보였으며, 특히 "수포화/건조 열전도도비"는 유효공극률과 매우 높은 상관성($R^2=0.90$)을 보였다.

• 보건교육건강증진학회지
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• 제18권1호
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• pp.109-125
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• 2001

The purpose of this study was to provide the basic data for establishing school education environment protection measures, on the basis of comparing and analyzing the realities and students' recognition degree of the environment and hygiene around the middle and high schools located in the rural areas. These study data were investigated by the self-administered questionnaires, taking as subject the 805 students in the middle and high schools located rural areas. And the results were as follows: First, as the result of having investigated the distribution degree of harmful environment within the purification zone around schools, it was found out that students responded: within the purification zone around the middle school, there were cartoon rooms (46.2％), electronic game rooms (45.9％), and singing rooms (45.0％). within the purification zone around the high school, there were electronic game rooms (46.3％), singing rooms (42.3％), billiard halls (41.4％), PC rooms (40.1 ％), and Soju-room (35.2％). Secondly, as having analyzed student's recognition degree of the harmful environment around the school, it was found out that middle school students responded that sexual utensils-treating shops (3.74 points) were most harmful, and next corrupted bathhouses (3.52 points), and Soju-room (3.47 points), and high school students also responded relating to harmfulness in a similar sequence. Thirdly, in case of students' recognition degree of the harmful environment around the school according to general characteristics, 1) girl students had a higher ratio of recognition that the environment around the school was harmful than boy students (p〈0.001). 2) groups of students whose living standard was high had a higher ratio of recognition that the environment around the school was harmful than groups of students whose living standard was low (p〈0.05). 3) groups of students whose school was located near the park or the residential street had a higher degree of recognition that the environment around the school was harmful than groups of students whose school was located near the factory or the shopping area (p〈0.01). 4) groups of students whose school was located near the park or the residential street had a higher degree of recognition that the environment around the school was harmful than groups of students whose school was located near the amusement area or the shopping area (p〈0.05). Fourthly, 1) relating to the harmful shops where they experienced most highly the behavior of drinking and smoking, middle school students responded that they did so in the electronic game room (22.5％) and high school students did so in the singing room (31.4％), and high school students had a very high experience ratio of drinking and smoking, compared with middle school students (p〈0.001). 2) relating to the harmful shops where they could get in contact with lewd articles, both of middle school students (5.3％) and high school students (8.3％) responded that they could do so in the video room. 3) relating to the harmful shops where they experienced unsound opposite sex acquaintance, both of middle school students (5.8％) and high school students (16.6％) responded that they did so most highly in hotels, and high school students had a remarkably high experience ratio of unsound opposite sex acquaintance, compared with middle school students (p〈0.05). 4) relating to the harmful shops where they experienced violence, middle school students responded that they did so in the electronic game room (14.0％) and then in the singing room (3.7％), and high school students responded that they did so in the electronic game room (9.3％), the nightclub (4.6％), Soju-room (4.1 ％), and high school students had a remarkably high experience ratio of violence, compared with middle school students (p〈0.05). 5) relating to the harmful places where they experienced drugs both of middle school students (0.8％) and high school students (2.4％) responded that they did so in the hotels. Fifthly, when going to the harmful shops, students had the experience of being guided and regulated roughly 1 time - 2 times, and middle school students (16.4％) and high school students (16.7％) had almost similar experience ratios of being guided and regulated. Conclusively, there was a limit in controlling the environment and purification zone only by legal regulations and institutional controls, the self-control purification effort for the school and the surrounding environment was required greatly, in order to protect students from harmful environment. In addition, the constant study to establish the educational environment purification measures must be carried out.

• 대한전자공학회논문지
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• 제4권4호
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• pp.2-12
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• 1967

MOS 전계효과 transistor를 이용하여 직류착동증폭기를 설계하여 A 정도의 극미소직류전류를 측정하는 장치에 관한 연구이다. 등가회로를 이용하여 전압이득과 동상전압변별비를 주는 식을 유도하였으며 유효등가 source 저항을 대단히 높이기 위한 정전류원회로의 실현을 위한 해석을 하였다. 전압이득은 6.6, 상온에서의 drift는 하루에 1.5mv 정도이고 동상전압변별비는 최고 84db 이었다. 이것은 MOS transistor의 대단히 높은 입력저항의 특징을 살려 전잡상등에서 나오는 극미소직류전류의 측정을 간단하게 할 수 있게 하는 것이다.