• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.75-84
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• 2018

This study investigated the pollution status of polycyclic aromatic hydrocarbons (PAHs) such as benzopyran, which is a harmful substance, in convergence herbal pills distributed in Seoul. During 2010 ~ 2013, 31 items and 93 samples were collected from the herbal medicines vendors in Seoul, and the samples were extracted, filtered, concentrated, and then spun out with SPE (Sep-pak florisil) and concentrated again and analyzed by liquid chromatography. The results of the analysis showed that the average contents of PAHs were below $10{\mu}g/kg$, and the PAHs were lower than those of daily life exposure, and MOEs was evaluated as safe to a negligible level. In the future, comparative fusion studies on the harmful substances of medicinal pills and food pills are needed.

• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.316-320
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• 1999

The purpose of this research was to estimate dewatering characteristics of generating water treatment plant by dewatering velocity, suitable polymer and mixing condition. Zeta potential of sludge in storage tank was negative and in case of adding cation, anion and nonion polymer for sludge conditioning, specific resistance coefficients of conditioned sludge were similar at zeta potential -5㎷. But above zeta potential -15㎷, canon polymer was more effective than others for reduction of specific resistance coefficients. Using of cation acrylate polymer showed better dewatering coefficients than cation methacrylate polymer.

• Journal of Environmental Impact Assessment
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• v.19 no.1
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• pp.29-38
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• 2010

At recent the number of livestock is increased and the size of farm has changed to large facilities in Korea. So the livestock facilities have become one of major sources of odor emission. The purpose of this study is to analyze the concentration and assessment of odor unit from livestock facilities for cow, dairy, swine and poultry. The eleven odor pollutants such as $H_2S$, ($CH_3$)SH, $(CH_3)_2S$, $(CH_3)_2S_2$, $CH_3N$, $NH_3$, $(CH_3)_2N$, $(CH_3)_3N$, butyric acid, valeric acid and isovaleric acid, measured for assessment of the odor concentrations from livestock facility. As the results, it is found that the major matters of odor from livestock facilities were $NH_3$ and $H_2S$. The highest concentration of $NH_3$ is measured as 15 ppm at henhouse and $H_2S$ is measured as 858 ppb at penpig facilities. In the comparison of the average odor unit from livestocks, it is found that the highest odor unit was from swine and the lowest odor unit was from cow facility. So odor unit from swine facilities was 12 to 30 times higher than the odor unit from cow facilities.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.7-21
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• 1993

The morphogenesis of the stifle joint in Korean cattle embryos and fetuses was observed by radiography, alizarin red S stain and light microscopy. Fourty-eight(48) embryos and fetuses, ranging from 11mm to 160mm in crown-rump length (C-R L), were used for this study. The experimental samples were divided into twelve separate groups according to their C-R L. The first to the nineth group ranged from 11-100mm in C-R L, spaced at 10mm intervals. The tenth to the twelfth group ranged in C-R L from 101mm to 160mm, and were spaced at 20mm intervals. The results were as follows; 1. The first appearance of the interzone between the femur and tibia was formed in the second experimental group. The patellar ligament and cruciate ligament appeared in the third group and the patella, menisci and synovial cavity appeared in the fourth group. 2. The lateral and medial menisci were first obseved in the fourth group, and these structures showed crescent shape in the fifth group of the fetuses. 3. The first appearance of the femoro-tibial joint cavity was in the third group. The fifth group contained the first appearance of the patello-femoral cavity. Also, the femoro-tibial cavity was divided into two cavities by the anterior and posterior cruciate ligament.

• Korean Journal of Materials Research
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• v.28 no.4
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• pp.195-200
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• 2018

This study investigated the effects of the post annealing temperatures on the electrical and interfacial properties of a metal-semiconductor-metal photodetector(MSM-PD) device. The interdigitate type MSM-PD devices had the structure Al(500 nm) / Ti(200 nm) / poly-Si(500 nm). Structural analyses of the MSM-PD devices were performed by employing X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscope(TEM). Electrical characteristics of the MSM-PD were also examined using current-voltage(I-V) measurements. The optimal post annealing condition for the Schottky contact of MSM-PD devices are $350^{\circ}C$-30minutes. However, as the annealing temperature and time are increased, electrical characteristics of MSM-PD device are degraded. Especially, for the annealing conditions of $400^{\circ}C$-180minutes and $500^{\circ}C$-30minutes, the I-V measurement itself was impossible. These results are closely related to the solid phase reactions at the interface of MSM-PD device, which result in the formation of intermetallic compounds such as $Al_3Ti$ and $Ti_7Al_5Si_{12}$.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.515-517
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• 2008

현재 가동 중인 원자적발전소 계측제어설비의 전원공급기를 살펴보면 인버터 또는 별도의 교류를 입력전원으로 사용한다. 직류 전원공급기들은 설비의 중요도예 따라 이중화로 구성된 설비도 있고 그렇지 않은 기기나 설비도 있다. 이중화로 구성된 전원공급기라 해도 교류 입력전원이 동일하다면 교류 입력이 상실될 때 이중화로 구성된 직류전원도 상실되어 관련계통의 가동이 정지된다. 이러한 문제점을 해결하기 위해서는 각기 다른 교류입력전원으로 동작되는 이중화전원공급기로 구성되는 것이 가장 바람직하다. 본 연구개발의 목적은 두 종의 설비에 소요되는 3종의 직류전원 공급기를 원자력 안정성등급으로 국산화하는 연구이다. 기존 제품들은 3종 모두 리니어 방식의 제품이지만, 방사선감시 계통 현장제어기의 5V로직 전원공급기와 공정제어계통 전원공급자는 전력변환효율이 높고 소형, 정량화가 가능한 SMPS(Switched Mode Power Supply) 방식으로 개발하였다. 방사선감시계통 현장제어기의 PCA(Printed Circuit Assembly) 저전압공급기는 다양한 종류의 출력전압과 저 전류형이므로 안정성 면에서 동일한 형식의 리니어 방식으로 개발하였으며 3종류 모두 출력용량을 20% 이상 향상시켰다. 또한, 논문을 통해 SMPS 방식의 전원공급기의 핵심 부품인 Control Module을 Hybrid IC형으로 자체 설계하여 성능이 우수한 제품을 지속적으로 생산할 수 있는 기틀을 마련하고자 한다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.286-286
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• 2009

A small PEM fuel cell has two different stack configurations such as active and passive stacks. The active stack has a distintion of high power density although it makes system complex by using alr blower and related BOPs resulting in large system volume. On the contrary, passive stack has an advantage of compact system because it doesn't need air supplying devices although it reveals relatively low stack power density. In this study we fabricated two 10W PEMFC stacks with different stack configurations, active and passive stacks, and tested their performance and stability. The active stack consists of 13cells with an active area of $5cm^2$. The passive stack has 12cells with an active area of $16cm^2$. When we compared the stack performance of those stacks, the active stack showed higher power density compared to the passive stack, particularly at high voltage regions. However, at low voltage and high current regions, the passive stack performance was comparable to the active stack. The stack stability was largely dependent on the fuel humidity, particularly for active stack. At low humidity conditions, the active stack performance was decreased continuously and the cell voltage distribution was not uniform showing seriously low cell voltage at center cells mainly due to the cell drying. The passive stack showed relatively stable behavior at low humidity and the stack performance was largely dependent on the atmospheric conditions.

• Journal of Applied Reliability
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• v.15 no.1
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• pp.44-51
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• 2015

In this study, we propose reliability prediction of a satellite by function analysis. To do so, the intended functions of the satellite are derived from using function structure block diagram, and defined as main, sub, and detailed functions. Furthermore, in order to generate function and reliability structure table, reliability model rule, duty cycle, and types of switch are assigned to the classified functions. This study also establishes reliability block diagram and mathematical reliability models to schematize the relationship among the functions. The reliability of the classified function is estimated by calculating the failure rate of parts comprising them. Finally, we apply the proposed method to a small satellite as a case study. The result shows that the reliability for the detailed function and the sub function as well as the main function could be predicted quantitatively and accurately by the proposed approach.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.305-313
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• 1998

Steroid hormone is known to cause the dynamic changes of mammalian uterus during reproductive cycle. However there is little information about the effect of estrogen (E) and progesterone (P) on the expression of various transcription factors involved in gene expression. Thus the present study was designed to demonstrate E and/or P-induced expression of c-Fos, CREB, ATF and HSP70 in rat uterus. Rats, ovariectomized (OVX) for two weeks, were divided into 6 experimental groups, 1) OVX, 2) OVX+V, 3) OVX+E, 4) OVX+P, 5) OVX+E+V, 6) OVX+E+P, and western blotting assay for nuclear extract and immunohistochemical staining were carried out for each experimental group. Treatment of E $(10{\mu}g)$ showed to increase the expression of c-Fos, CREB, ATF, and HSP70, and maximal expression was occured at $3\sim6$ hr after E administration. P (1mg) also increased, but much less than E, the expression of c-Fos, ATF, and HSP70. However, P did not reveal any effect on the expression CREE. P treatment 4 hr after E injection decreased c-Fos, CREB, and ATF expression, but did not show any change in the E-induced HSP70 expression. In immunohistochemical study c-Fos-, CREB-, and ATF-immunoreactivities were confined to the cells of luminal epithelium of uterine endometrium. These results suggest that proliferation and differentiation of rat uterus during reproductive cycle may mediated via expression of transcription factors, such as c-Fos, CREB, ATF, and HSP70.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.373-379
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• 2010

Purpose: The purpose of this study was to investigate the effect of vision training using MYSTERY CIRCLE system on patients with exophoria and intermittent extropia. Mehtods: The vision training observation group consists of 26 clients who had exophoria (n=18) and intermittent extropia (n=8) without opthalmic diseases or vertical phoria. Our clients took each vision training once a week for eight weeks and were investigated for the symptoms changes of binocular vision. Results: According to the results, MISTERY CIRCLE vision training methods improved the binocular vision function and sensation symptoms. For Worth 4 Dot test, Titmus test and red lenses showed fusion rate changes. Conclusions: The study proved that MISTERY CIRCLE vision training system for patients with binocular vision was effective for the improvement of the binocular vision symptoms of these patients.