• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.691-695
• /
• 2000

This paper present the result of the investigation, the electric properties of insulators due to non-soluble contamination. In general, the humidity and the amount of soluble salts such as NaCl, MgCl$_2$are the most dominant factor. Though the non-soluble do not distribute on conductivity of contaminant layer, that has the hygroscopic property. For this study, we make a mini-fog chamber with transparent acryl and the kaoline was used for non-soluble contaminant. The kaoline was applied with sprayer to get the specific ESDD and NSDD value, then the specimen was dried and installed horizontally. And to measure the leakage current a DAS system was developed with LabView. With the result, we could know the influence of non-soluble content and the relationship between NSDD and ESDD.

• Bulletin of the Korean Chemical Society
• /
• 제18권6호
• /
• pp.640-643
• /
• 1997

Pure titanium dioxide $(TiO_2)$ films were prepared by pulsed laser deposition on a single crystal Si(100) substrate. We have investigated the growth of crystalline titanium dioxide films with respect to substrate temperature and ambient oxygen pressure. The structural properties of the films were analyzed by X-ray diffraction. We found that the anatase as well as the rutile phases could be formed from the original rutile phase of the target $TiO_2$. At 0.75 torr of ambient oxygen pressure, the structure of $TiO_2$ film was amorphous at room temperature, anatase between 300 and 600 ℃, a mixture of anatase and rutile between 700 and 800 ℃, and only rutile at 900 ℃ and above. However, at a low ambient oxygen pressure, the rutile phase became dominant; the only rutile phase was obtained at the ambient oxygen pressure of 0.01 torr and the substrate temperature of 800 ℃. Therefore, the film structures were largely influenced by substrate temperature and ambient oxygen pressure.

• Bulletin of the Korean Chemical Society
• /
• 제12권2호
• /
• pp.170-177
• /
• 1991

A lattice mean field theory is developed to investigate the conformational properties of monolayer amphiphiles at the air-water interface. By generalizing Dill and Cantor's method and by extending Whittington's recurrence equation, we derive the supermatrix recurrence equation which is applied to calculation of various segment density profiles and order parameter, etc. In deriving the equation, we incorporated the chain stiffness effect and the chain connectivity which are distinguished features of linear chain molecule. Our result shows that, as the surface coverage $\sigma$ increases the chain ordering process with respect to vertical axis of the lattice system becomes dominant.

• 한국토양비료학회지
• /
• 제29권2호
• /
• pp.199-206
• /
• 1996

휴경논의 증가가 쌀 생산량 감소의 원인이 됨에 따라 휴경논의 합리적 재이용을 위한 생태환경 변화 양상을 구명하기 위하여 중서부 평야 기후권에 속하는 경기도(수원 외 9)지역을 대상으로 휴경년수별로 토양특성과 식생변화를 조사한 결과는 아래와 같다. 1. 휴경논 토양의 pH, Ca, Mg 변동(變動)은 휴경기간이 길수록 심토보다 표토부분이 증가(增加)하는 경향을 나타내었다. 2. 미생물상은 휴경기간이 길수록 세균은 감소하고, 방선균은 증가 하였으나, 사상균은 변화가 작은 경향을 나타내었다. 3. 휴경논의 식생에 대한 휴경기간별 분포비율을 평균(平均)해서 비교해보면 일년생은 1년: 89.5%, 2년: 30.7%, 3년: 33.1% 다년생은 1년: 10.5%, 2년: 69.3%, 3년: 66.9%로 일년생 초종에서 급격히 다년생 초종으로 변화하였고, 초종수(草種數)도 종합하면 1년: 38종(種), 2년: 37종(種), 3년: 25종(種)으로 감소하는 경향을 보였다. 4. 휴경논에서 자라는 버드나무는 휴경기간이 길수록 본수, 직경, 초장이 증가하였으며 휴경논의 재경작시 가장 큰 문제 식생으로 생각되었다.

• 한국표면공학회지
• /
• 제50권3호
• /
• pp.206-211
• /
• 2017

$BiNbO_4:RE^{3+}$ (RE = Dy, Eu, Sm, Tb) phosphors were prepared by solid-state reaction at $1100^{\circ}C$ and their structural, photoluminescent, and morphological properties were investigated. XRD patterns exhibited that all the synthesized phosphors exhibited a triclinic system with a dominant (210) diffraction peak, irrespective of the type of activator ions. The surface morphologies of rare-earth-ion-doped $BiNbO_4$ phosphors were found to depend strongly on the type of activator ions. The $Eu^{3+}$ and $Dy^{3+}$ doped $BiNbO_4$ phosphors revealed a strong red (613 nm) emission resulting from the $^5D_0{\rightarrow}^7F_2$ transition of $Eu^{3+}$ and a dominant yellow (575 nm) emission originating from the $^4F_{9/2}{\rightarrow}^6H_{13/2}$ transition of $Dy^{3+}$ respectively, which were the electric dipole transitions, indicating that the activator ions occupy sites of non-inversion symmetry in the $BiNbO_4$ phosphor. The main reddish-orange emission spectra of $Sm^{3+}$-doped $BiNbO_4$ phosphors were due to the $^4G_{5/2}{\rightarrow}^6H_{7/2}$ (607 nm) magnetic dipole transition, indicating that the $Sm^{3+}$ ions were located at inversion symmetry sites in the $BiNbO_4$ host lattice. As for $Tb^{3+}$-doped phosphors, green emission was obtained under excitation at 353 nm and its CIE chromaticity coordinates were (0.274, 0.376). These results suggest that multicolor emission can be achieved by changing the type of activator ions incorporated into the $BiNbO_4$ host crystal.

• 한국운동역학회지
• /
• 제25권1호
• /
• pp.29-37
• /
• 2015

Objective : The purpose of this study was to investigate the biomechanical properties of shock absorption strategy and postural stability during the drop landing for each types. Methods : The motions were captured with Vicon Motion Capture System, with the fourteen infra-red cameras (100Hz) and synchronized with GRF(ground reaction force) data(1000Hz). Ten male soccer players performed a drop landing with single-leg and bi-legs on the 30cm height box. Dependent variables were the CoM trajectory and the Joint Moment. Statistical computations were performed using the paired t-test and ANOVA with Turkey HSD as post-hoc. Results : The dominant leg was confirmed to show a significant difference between the left leg and right leg as the inverted pendulum model during Drop Landing(Phase 1 & Phase 2). One-leg drop landing type had the higher CoM displacement, the peak of joint moment with the shock absorption than Bi-leg landing type. As a lower extremity joint kinetics analysis, the knee joint showed a function of shock absorption in the anterior-posterior, and the hip joint showed a function of the stability and shock absorption in the medial-lateral directions. Conclusion : These findings indicate that the instant equilibrium of posture balance(phase 1) was assessed by the passive phase as Class 1 leverage on the effect of the stability of shock absorption(phase 2) assessed by the active phase on the effect of Class 2 leverage. Application : This study shows that the cause of musculo-skeletal injuries estimated to be focused on the passive phase of landing and this findings could help the prevention of lower damage from loads involving landing related to the game of sports.

• 한국식품과학회지
• /
• 제50권4호
• /
• pp.400-406
• /
• 2018

본 연구는 국내 수도권, 충청, 강원 등지의 중소기업형 소규모 양조장에서 생산되는 탁주와 약주의 미생물 군집 분포를 차세대 염기서열 분석기법을 이용하여 조사하였다. 각 시료별로 미생물 분포에 따른 품질의 차이를 나타냈으며 특히 백미 또는 소맥분을 주로 사용한 탁주와 달리 약주는 찹쌀과 백미를 주원료로 사용하여 각각 독특한 주질과 미생물 분포에 영향을 주었다. 주요검출 미생물로 진균류는 S. cerevisiae가 대부분을 차지하였으며 세균의 경우 Firmicutes문에는 유산균인 Lactobacillus, Leuconostoc, Lactococcus, Weisella 속 등이 우점종으로 확인되었다. 곡물인 원재료에 의해 Cyanobacteria 문의 Chloroplast 속과 제조 환경에 의한 유입으로 추정되는 Cronobacter 속, Enterobacter 속 또한 검출되었다. 이러한 다양한 미생물의 분포는 제조 지역, 주원료, 그리고 제조 방법에 기인할 것으로 판단되며 명확한 상관관계는 확인할 수 없었으나 본 연구 결과 유통과정의 제품 안전성 확보를 위해 양조장별 미생물 관리가 필요할 것으로 판단된다.

• 한국대기환경학회지
• /
• 제31권2호
• /
• pp.131-142
• /
• 2015

This study investigated physicochemical and optical characteristics for three episodes of Asian dust, stagnant haze and long-range transport haze and for one clean day. $PM_{10}$ mass concentration during Asian dust and two haze days was increased by 2~9 times compared to that of clean episode. During Asian dust episode, coarse particle concentration was increased and the mass concentration of calcium in a coarse mode ($1.8{\sim}10{\mu}m$) was $5.4{\mu}g/m^3$ which was 7 times higher than that of clean episode. The calcium was presented as a form of $CaCO_3$ in a coarse mode. During the two haze episodes, fine particle (< $1.8{\mu}m$) concentration was increased and secondary inorganic pollutants such as sulfate, ammonium and nitrate composed of 90% of the total ions. $(NH_4)_2SO_4$ and $NH_4NO_3$ were dominant in a fine mode for stagnant haze episode. But they were the most dominant form in both fine mode and coarse mode for long-range transport haze episode. According to the optical properties for each episode (Asian dust, stagnant haze and long-range transport haze) were classified as dust, black carbon and mixture, respectively.

• 동굴
• /
• 제56권
• /
• pp.15-38
• /
• 1998

Biomass and soil properties of plant communites was investigated in the limestone ares, Tanyang, Ch'ungbuk Province in Korea. Plants was classified in calcicoles and calcifuges within plant communities occurring in the limestone area. Biomass of plant populatins in the limestone area was measured that Stellaria aquatica was the lowest(0.58g/plant), Chrysanthemum boreale was the highest(8.87g/plant) and that Pennisetum alopecuroides, Miscanthus sinensis was 6.67g/plant, 5.76g/plant, respectively. Diameter of breast height among the tree layer communities was investigated that Pinus densiflora was the widest(20cm), Juniperus rigida was the narrowest(6cm) and that Quercus aliena, Populus ${\times}$ tomentiglandulosa was 10cm, 12cm, respectively. The high of density in the tree layer was found out Populus ${\times}$ tomentiglandulosa, Juniperus rigida, Quercus aliena, Pinus densiflora in this order. Dominant species in the study area were Pinus densiflora, Quercus aliena, Juniperus rigida, Quercus dentata in the tree layer, Lespedeza bicolor, Buxus microphylla, Rhus chinensis in the shrub layer, Humulus Japonicus, Erigeron canadensis, Xanthium strumarium, Oenothera odorata Persicaria hypropiper on the riverside, Pennisetum alopecuroides, Vicia amoena, Chrysanthemum boreale on the roadside. Soil properties of the limestone area was investigated around the protrusion of rock in the upper region, around the cave and underlayer accumulated by corrosion in the study area. Lime-chlorosis was observed in the upper region, underlayer and around the cave. It was observed that biota of kum-gul and dungbong-gul was Rhinolophus ferrumequinum korai, Epanerchodus kimi, Antrokoreana gracilipes, Diestrammena japonical. Dominant species were Humulus japonicus, Stellaria aquatica, Hydrocotyle maritima, Phragmites communis, Miscanthus sinensis around the inlet of a kum-gul. It was classified that plants in the study area was 34 order, 53 family, 135 species in all. Calcicoles were 11 order, 16 family, 18 species and calcufuges were 6 order, 8 family, 11 species of them all.

• 한국지형학회지
• /
• 제17권2호
• /
• pp.41-52
• /
• 2010

양양 오산리 쌍호 일대의 신석기 유적지가 입지한 해안사구(S1)와 쌍호 가장자리 충적층(S4)에서 얻은 토양으로 화분분석을 행하고, 두 지점의 지형특성과 관련하여 고식생환경을 복원하였다. 신석기 유구 위에 퇴적된 해안사구(S1)의 저습지는 약 4,000년 BP 경부터 형성되었던 것으로 추정된다. 흑송(해송)이 전 시기동안 번성하였으며, 약 2,000년 BP를 경계로 화분대가 구분되었다. 화분대 I시기는 AP가 우점한 가운데 국화과가 우세하였고, 화분대 II는 벼과, 쑥속, 메밀 등을 중심으로 하는 NAP 우점기로서 농경 시기의 특징을 보였다. 쌍호 가장자리 충적층(S4)에서는 상부유기질층이 형성될 때, 습지 가장자리에서 번성한 오리나무속을 중심으로 하는 낙엽활엽수림과 벼과, 쑥속, 국화과, 부들속, 산형과, 여뀌속이 번성하였다. 전 시기동안 초본화분(NAP)이 목본(AP)에 비해 우점하므로, 해안사구(S1)의 화분대 II시기와 대비된다.