• 한국염색가공학회지
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• 제35권2호
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• pp.67-81
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• 2023

This study aims to examine the possibility of using dried Dondropanax morbiferus extract as a functional dye. The leaves and branches of were extracted with distilled water and 30% ethanol, and the dyeability and functionality of silk fabrics were examined according to the color characteristics of the extract and dyeing conditions. As a result of analyzing the ultraviolet and visible light absorption spectrum of the extract, it was possible to confirm the peak of flavonoid belonging to polyphenol, and the peak of riboflavin expressing yellow color was confirmed. Adsorption equilibrium was observed at 4% dyeing concentration and 60 minutes of dyeing time, and as the temperature increased, dyeing amount increased without color change of Y-series. Aluminum mordanting also increased the yellow color. The color fastness of washing and UV irradiation was low, but the color fastness of rubbing was evaluated as relatively good. The silk fabric dyed with the distilled water extract of the leaves showed a 99.9% bacteriostatic reduction against Staphylococcus aureus and Klebsiella pneumoniae, showing excellent antibacterial properties.

• 공업화학
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• 제29권1호
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• pp.56-61
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• 2018

황-요오드(SI) 공정의 통합 운전을 위한 분젠 반응 단계에서, $I_2$ 및 $H_2O$ 반응물들은 $HI_x$ 용액 내 용해된 성분들로써 공급된다. $HI_x$ 용액과 $SO_2$ 공급을 이용하여 분젠 반응이 수행될 때 $HI_x$ 상 내 대부분의 $H_2SO_4$ 생성물이 존재하며, 이에 따라 $HI_x$ 상에 대한 $H_2SO_4$ 상의 부피 비가 매우 낮다. 본 연구에서 우리는 상 분리 성능을 향상시키기 위해 $HI_x$ 용액을 이용한 분젠 반응에 대한 초음파 조사의 효과들을 연구하였다. 분젠 반응과 함께 초음파가 조사될 때 $HI_x$ 상으로부터 $H_2SO_4$ 상으로 이동된 $H_2SO_4$의 양은 최대 58.0 mol%까지 증가하였으며, $H_2SO_4$ 상의 부피 또한 최대 13.1 vol%까지 증가하였다. 특히, 상 분리에 대한 초음파 조사의 효과는 온도, $I_2$ 및 $H_2O$ 공급 농도가 감소함에 따라 향상되었다. 초음파 조사는 $HI_x$ 상 내 반응 평형을 미시적으로 이동시킴으로써 추가적인 $H_2O$ 분자들의 형성을 유도하였다. 이로부터 추가적으로 생성된 $H_2O$ 및 분리된 $H_2SO_4$ 분자들이 $H_2SO_4$ 상으로 이동할 수 있는 더 많은 $H_2SO_4{\cdot}xH_2O$ (x = 5-6) 착물들을 형성하였다.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.846-849
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• 2013

$TiO_2$ 박막을 저온 열처리 졸-겔 법으로 합성하였다. 박막의 기판은 면적이 $100mm^2$인 붕규산염 유리를 사용하여 시료를 $300^{\circ}C$부터 $1100^{\circ}C$까지 열처리하였고, 이때 제조된 박막의 두께는 약 $1.5{\mu}m$정도였다. $300^{\circ}C$에서 2시간 동안 열처리한 $TiO_2$ 박막은 아나타제 상을 나타내었고 열처리 온도가 증가함에 따라 비정질 상태에서 아나타제상과 루타일 상이 공존하면서 각 상의 분율이 변화하였다. SEM 분석에 의하면 박막의 입자 크기는 $0.1{\sim}0.54{\mu}m$이었으며 Uv-visible 반사특성에 있어서 390nm부근에서 광흡수가 되는 것을 알 수 있었다. 따라서 낮은 열처리 온도에서 생성된 $TiO_2$ 박막은 주로 아나타제 상을 가지며 광촉매 특성을 2.4배 증가시키는 것으로 나타났다.

• 한국태양에너지학회 논문집
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• 제36권2호
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• pp.41-51
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• 2016

A solar air heater was designed for supplementary domestic heating. The absorber plate had a series of protruding notches which had triangular openings on the front surface of the absorber plate to direct partial air flow to the rear surface and to enhance the convective heat transfer to the flowing air. The height of the opening as well as the opening configuration was determined by preceding numerical simulations. The experimental model had an absorber plate of 0.78-m width and 1.0-m length which was coated with black paint. The air temperature increased as much as $18^{\circ}C$ for $90-m^3/h$ flow rate when the absorber plate was inclined by $45^{\circ}$ for a clear-day solar irradiation of about $906W/m^2$. The collector efficiency ranged from 69 to 74%. Considering the simplicity of the structure and low manufacturing cost, the solar air heater might have competence as an auxiliary heating device for domestic use. On-site experimental results are presented with discussion for various solar irradiations and air flow conditions.

• 한국환경과학회지
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• 제20권12호
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• pp.1521-1531
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• 2011

This study was carried out to determine the characteristics of the marine environment, including nutritional content, in order to clearly understand the outbreaks of Gonyaulax polygramma in the southern coastal areas in August, 2009. Samples were collected at 13 sites and water temperature and salinity were measured using a CTD. Field surveys were twice: the first between August 5-7, the second between August 22-24. The cell density of G. polygramma was 6,500-10,000 cells $ml^{-1}$ during the $1^{st}$ survey, whereas during the $2^{nd}$ survey the range of the cells was recorded from 8,000 to 12,500 cells $ml^{-1}$. Cochlodinium polykrikoides ranged from 0 to 105 cells $l^{-1}$ during the field survey. In water environments, the majority stations during the $1^{st}$ survey showed a nearly homogeneous water column below $1^{\circ}C$ in temperature, as well as similar profiles of salinity. However, the stratification between the surface and bottom was observed in the $2^{nd}$ survey. Regarding nutrients, Dissolved Inorganic Nitrogen (DIN) in the surface ranged from 0.144 to 0.236 mg $l^{-1}$ during the $1^{st}$ survey, and 0.082-0.228 mg $l^{-1}$ during the $2^{nd}$ survey. DIP (Dissolved Inorganic Phosphorus) did not show any difference in concentration between the $1^{st}$ and $2^{nd}$ survey. During August of 2009, the wind speed in the southern waters remained at around ${\leq}2\;m\;s^{-1}$ for about 60% of time, and there was very little precipitation during the month. Irradiance of ${\geq}10$ hr was shown in the late of August. It is thought that a low level of DIN and salinity play an important role as an essential factor for rapid growth, wide distribution and longer duration of red tide in G. polygramma.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.81-83
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• 2000

Tin-doped indium oxide(ITO) thin films were deposited on polyethylene terephthalate(PET) at room temperature by oxygen ion beam assisted evaporator system and the effects of oxygen gas flow rate on the properties of room temperature ITO thin films were investigated. Plasma characteristics of the ion gun such as oxygen ions and atomic oxygen radicals as a function of oxygen flow rate were investigated using optical emission spectroscopy(OES). Faraday cup also used to measure oxygen ion density. The increase of oxygen flow rate to the ion gun generally increase the optical transmittance of the deposited ITO up to 6sccm of $O_2$ and the further increase of oxygen flow rate appears to saturate the optical transmittance. In the case of electrical property, the resistivity showed a minimum at 6 sccm of $O_2$ with the increase of oxygen flow rate. Therefore, the improved ITO properties at 6 sccm of $O_2$ appear to be more related to the incorporation of low energy oxygen radicals to deposited ITO film rather than the irradiation of high energy oxygen ions to the substrate. At an optimal deposition condition, ITO thin films deposited on PET substrates showed the resistivity of $6.6{\times}10^{-4}$ ${\Omega}$ cm and optical transmittance of above 90%.

• 한국태양에너지학회 논문집
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• 제29권1호
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• pp.32-37
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• 2009

Photovoltaic(PV) permits the on-site production of electricity without concern for fuel supply or environmental adverse effects. The electrical power is produced without noise and little depletion of resources. So BIPV(Building-Integrated Photovoltaic) system have been increased around the world. Hereby the relative installation costs of the system will be relatively low compared to traditional installations of PV in high-rise buildings. This paper examined possibility of building integrated balcony PV system and analyzed both performance and problems of this system. The system is influenced by conditions such as irradiation, module temperature, shade and architectural component etc. If this BIPV system of 1.1kW is possible the natural ventilation in the summer case, the temperature of PV module decrease and then the efficiency of PV system increase generally. By the results, the annual averaged PR of BIPV system of cold facade type is about 74.7%.

• Current Applied Physics
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• 제18권12호
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• pp.1577-1582
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• 2018

While controlling the cation contents in perovskite rare-earth nickelate thin films, a metal-to-insulator phase transition is reported. Systematic control of cation stoichiometry has been achieved by manipulating the irradiation of excimer laser in pulsed laser deposition. Two rare-earth nickelate bilayer thin-film heterostructures with the controlled cation stoichiometry (i.e. stoichiometric and Ni-excessive) have been fabricated. It is found that the Ni-excessive nickelate film is structurally less dense than the stoichiometric film, albeit both of them are epitaxial and coherent with respect to the underlying substrate. More interestingly, as a temperature decreases, a metal-to-insulator transition is only observed in the Ni-excessive nickelate films, which can be associated with the enhanced disproportionation of the Ni charge valence. Based on our theoretical results, possible origins (e.g. anti-site defects) of the low-temperature insulating state are discussed with the need of future work for deeper understanding. Our work can be utilized to realize unusual physical phenomena (e.g. metal-to-insulator phase transitions) in complex oxide films by manipulating the chemical stoichiometry in pulsed laser deposition.

• Nuclear Engineering and Technology
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• 제39권5호
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.

• 생물환경조절학회지
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• 제22권2호
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• pp.100-107
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• 2013

본 연구에서 사용한 QRD(Quadratic Residue Diffusor) 마이크로파는 일반적인 마이크로파와 달리 파장의 위상차를 변화시켜 균일한 살균을 유도할 수 있어 저전력으로 효과를 높일 수 있는 새로운 기술로 알려져 있다. 따라서 친환경적이고 에너지 소비가 적은 QRD 마이크로파를 이용하여 식물공장에 이용되고 있는 배지를 멸균할 수 있는 가능성에 대한 기초적인 연구를 수행하여 얻은 결과는 아래와 같다. 마이크로파의 조사 출력에 따른 배지의 외적변형은 배지 내의 수분의 함유량과 마이크로파 출력을 2~8kW까지에서 우레탄스폰지와 암면은 외적변형이 전혀 일어나지 않은 것으로 확인되었다. 그러나 PDA고체배지는 2kW 출력에 60초와 180초에서는 배지가 녹지 않았고, 그 외 처리에서는 전부 배지가 녹았다. Bacillus sp.와 Burkholderia sp.에서 마이크로파의 조사 출력과 처리시간에 따른 균주 표면 온도는 차이가 나타났다. 마이크로파의 조사 출력과 처리시간에 따른 균주 멸균 실험은 마이크로파의 출력 2kW에서 시간과 관계없이 Bacillus sp.와 Burkholderia sp.는 모두 자라고 있는 것을 확인하였고, 마이크로파의 출력 6kW에서는 Burkholderia sp.의 60초 처리를 제외한 모든 실험구에서 멸균되었으며, Bacillus sp.는 모든 실험구에서 사멸되었다. 마이크로파의 출력 8kW에서 시간과 관계없이 Bacillus sp.와 Burkholderia sp.는 모두 멸균되었음을 확인하였다. 균주를 각각의 배지에 오염시킨 후 마이크로파를 처리한 배지 내의 온도는 처리시간 60초 지난 뒤에는 우레탄스폰지와 암면배지에서의 온도가 $100^{\circ}C$ 이상으로 유지되어 대체로 60초 부터 멸균이 가능한 것으로 판단되었다. 따라서 식물공장내에 가장 문제가 되고 있는 Bacillus sp.와 Burkholderia sp.는 본 실험에서 사용된 QRD 마이크로파로 충분히 멸균될 수 있을 것이라 판단된다.