• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.159-159
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• 1999

니켈 산화물 박막을 전자비임 증착법으로 기판온도는 RT~25$0^{\circ}C$의 범위에서 제작하였다. 제작시 초기 베이스 압력은 2$\times$10-6mbar로 하고 산소주입후 작업진공도를 3$\times$10-4mbar로 유지하여 증착하였다. 제작시 기판온도에 따라 제작된 시료들은 각각 X선회절장치(XRD)로 막의 구조과 그림과 같이 입방체 구조 또는 팔면체구조를 갖음을 알 수 있었으며 막의 표면형상은 SEM을 이용하여 분석하였다. 각각의 여러 기판온도에 따라 제작된 니켈 산화물 박막의 전기 화학적인 특성을 분석하기 위해 순환전압전류법을 이용하였다. 또한, 전기적인 광학소자로써의 특성을 분석하기 위해 UV-Vis 광분광기를 사용하여 투과율을 측정하여 그 특성을 알아보았다. 순환전압전류법에 의한 각 시료에 대한 박막의 전기화학적 특성은 0.5M KOH 전해질 수용액에서 기판온도가 150~20$0^{\circ}C$로 제작된 니켈 산화물 박막이 다른 온도에서 제작된 시료들보다 높은 전기화학적 안정성을 보임을 알 수 있었다. 마찬가지로 광학적 특성에서 착색과 탈색의 순환과정시 분광광도계에서 나타나는 광투과율을 비교해 보면 100~20$0^{\circ}C$에서 제작된 니켈 산화물 박막이 가역적인 착탈색의 색변화가 현저하게 나타남을 알 수 있었다. 결과적으로 광학적 특성 및 전기화학적 안정성 분석으로 인해 막의수명과 전기적착색 물질의 특성면에서 증착시 기판온도가 150~20$0^{\circ}C$에서 제작된 시료가 가장 내구성면에서 막의 이온 누적이 적고 활성적인 광투과율의 성질을 갖는다는 것이다. 이와같이 니켈산화물 박막제작시 기판온도가 전기적착색물질의 특성과 내구성에 큰 영향을 미침을 분석할 수 있었다.electron Microscopy)과 AFM(Atomim Force microscopy)으로 증착박 표면의 topology와 roughness를 관찰하였다. grain의 크기는 10nm에서 150nm이었고 증착막의 roughness는 4.2nm이었다. 그리고 이 산화막에 전극을 형성하여 유전 상수와 손실률 등을 측정하였다. 이와 같이 plasma를 이용한 3-beam에 의한 증착은 금속의 산화막을 얻는데 유용한 기술로 광학 재료 및 유전 재료의 개발 및 연구에 많이 사용될 것으로 기대된다.소분압 조건에서 RuO2의 형성을 관찰하였으며, 이것은 열역학적인 계산을 통해서 잘 설명할 수 있었다.0$\mu\textrm{m}$, 코일간의 간격은 100$\mu\textrm{m}$였다. 제조된 박막 인덕터는 5MHz에서 1.0$\mu$H의 인덕턴스를 나타내었으며 dc current dervability는 100mA까지 유지되었다. CeO2 박막과 Si 사이의 결함때문이라고 사료된다.phology 관찰결과 Ge 함량이 높은 박막의 입계가 다결정 Si의 입계에 비해 훨씬 큰 것으로 나타났으며 근 값도 증가하는 것으로 나타났다. 포유동물 세포에 유전자 발현벡터로써 사용할 수 있음으로 post-genomics시대에 다양한 종류의 단백질 기능연구에 맡은 도움이 되리라 기대한다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상 분사기술의 최적

• Composites Research
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• v.14 no.3
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• pp.18-31
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• 2001

Interfacial and microfailure properties of the modified steel, carbon and glass fibers/cement composites were investigated using electro-pullout test under tensile and compressive tests with acoustic emission (AE). The hand-sanded steel composite exhibited higher interfacial shear strength (IFSS) than the untreated and even neoalkoxy zirconate (Zr) treated steel fiber composites. This might be due to the enhanced mechanical interlocking, compared to possible hydrogen or covalent bonds. During curing process, the contact resistivity decreased rapidly at the initial stage and then showed a level-off. Comparing to the untreated case, the contact resistivity of either Zr-treated or hand-sanded steel fiber composites increased to the infinity at latter stage. The number of AE signals of hand-sanded steel fiber composite was much more than those of the untreated and Zr-treated cases due to many interlayer failure signals. AE waveforms for pullout and frictional signals of the hand-sanded composite are larger than those of the untreated case. For dual matrix composite (DMC), AE energy and waveform under compressive loading were much higher and larger than those under tensile loading, due to brittle but well-enduring ceramic nature against compressive stress. Vertical multicrack exhibits fur glass fiber composite under tensile test, whereas buckling failure appeared under compressive loading. Electro-micromechanical technique with AE can be used as an efficient nondestructive (NDT) method to evaluate the interfacial and microfailure mechanisms for conductive fibers/brittle and nontransparent cement composites.

• Journal of Mushroom
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• v.12 no.3
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• pp.209-215
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• 2014

Changes in physical and chemical properties of oak sawdust were investigated by depth and time for 46 days during the fermentation process of 33 tons of the sawdust for oak mushroom cultivation. The degrees of change in the properties of the sawdust differed depending on the depth and fermentation period. Most of the physical-chemical properties except temperature and pH gradually changed during the fermentation. The temperature change was highly sensitive to the environment at the surface sawdust to 20 cm depth, while it gradually increased to the maximum $58.9^{\circ}C$ at 40~100 cm depths in 12 days and slowly to the maximum at 150 cm depth in 24 days. The moisture content of the sawdust decreased gradually from 31% to 26.5~28.0% in 24 days. Of the chemical properties during the fermentation, pH generally rose from 5.2 to 5.6, but it decreased to 4.4~4.7 at 150 cm depth in 16 days. While the carbon content of the sawdust was 68~70% without significant change, nitrogen content increased from 0.22% to 0.25% and thus C/N ratio gradually lowered from 320 to 280. P content in the sawdust gradually increased from 0.005% to 0.022% for 46 days. Osmotic concentration of the hot water extract of the sawdust varied 41.5~44.2 mmol/kg without significant change by the depth and time. The starch particles within initial ray parenchyma cells of sawdust decreased and fungal hyphae formed on the surface of the sawdust granules and within xylem vessel cells in 35 days. The effect of the sawdust fermentation on oak mushroom cultivation needs continued research.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.143-143
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• 2003

최근 생활수준 및 생활환경의 향상에 힘입어 청결 및 쾌적을 추구하는 것이 사회적 현상으로 나타나고 있다. 요즘처럼 현대화된 시대에 '왜 항균제가 필요한 것일까' 라는 자연스러운 의문이 발생하게 되지만 현실은 항균제를 이용한 다양한 항균제품, 항균가전제품, 항균가공 내ㆍ건자재 및 항상 신선한 선도를 유지할 수 있는 제품 등이 호황을 누리고 있는 것이 현실이며 그 시장 규모는 3,000억원을 상회하고 있다. 이러한 항균 가공제품이 호평을 받는 사회적 배경은 우리를 둘러싼 주변 삶의 경제환경 신장에 따른 쾌적성 추구와 밀접한 관련이 있을 것이다. 이처럼 항균기능이 부여된 제품이 호평을 받고 있음에도 불구하고 국내에서는 항균제품의 주 기능 역할을 하는 항균제에 대한 개발은 초기단계로 국내 시장에서 많은 연구가 이루어지고 있는 실정이다. 국내의 경우, 유기 항균제의 사용이 전체 사용량의 80%를 차지하고 있고, 제올라이트나 인산염을 무기 담체로 항균성 금속 이온(Ag, Zn)을 물리적으로 결합시킨 무기 항균제가 개발된 것이 최근의 기술 수준이다. 이러한 유기 항균제는 미생물의 번식을 억제 또는 사멸시키기 위한 것이지만, 생체의 피부 세포에도 영향을 줄 수 있는 피부 자극원의 하나로 그 사용이 점차로 제한되고 있다. 무기 항균제는 안정성이나 항균력에서는 유기항균제 보다는 뛰어나지만 가격(경제성)이나 색(Color), 사용성 (Application)측면에서는 여러 가지 문제를 나타내고 있다. 귀금속이므로 가격이 고가이며, 금속고유의 색으로 회귀하려는 플라즈몬 효과에 의해 색(Color)의 조절이 불가능, 분말형태이므로 지류에 첨가시키는 방법 등이 큰 문제로 부각되고 있다. 이 러한 문제점을 해결할 수 있는 기술이 나노기술이다 나노기술(Nano-Technology)은 물질을 분자, 원자단위에서 규명하고 제어하는 기술로서 원자, 분자를 적절히 결합시킴으로서 기존 물질의 변형, 개조는 물론 신물질의 창출을 가능케 하는 기술이다. 나노기술은 여러분야로 세분화되지만 그중 산업화에 가장 접목이 용이한 기술이 나노입자(Nano-Particle)제어 기술이며, 나노입자는 통상적으로 입자크기가 수 nm에서 100nm이하 크기의 넓은 표면적을 가진 콜로이드 상의 불균일 분산입자를 말한다. 나노입자(Nano-Particle)는 기존의 입자($\mu\textrm{m}$)보다 물리적 및 광학적 성질이 우수하고 그 자체의 기능면에서도 탁월하기 때문에 국내외의 여러 산업에서도 기존제품의 품질 향상 및 기능성부여, 기존 공정의 개선 및 생산 원단위 절감 등 경제적, 생산적인 측면을 고려하여 적합한 나노입자를 채택, 적용하고자 하는데 많은 노력을 기울이고 있다. 이에 천연 항생제로 알려진 Ag, 즉 항균 및 탈취, 전기적 기능이 우수한 은(silver, Ag)을 나노(nm) 입자희 제조하고 이와 더불어 이산화티탄(TiO2) 복합 분체를 제조하여 제조된 나노 입자 및 복합 분체를 사용함으로써 환경 친화적이며 다양한 용도로 활용 가능한 소재 개발에 연구 내용을 두고 있다. 본 연구를 통한 기대 효과로서 환경성 측면에서는 환경 친화적인 나노 입자의 제조로 기능성 나노 입자에 친 환경성을 부여하여 유기계 항균제 대체 효과를 발현하고 이를 제품에 적용함으로써 다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상 분사기술의 최적화에 의한 기능성 나노 입자 제조 기술을 확립하고 2차 오염 발생원인 유기계 항균제를 무기계 항균제로 대체할 수 있다. 이와 더불어 안료의 형상 균일화 기술을 확보하여 가격 경쟁력 및 부가가치 향상을 기대할 수 있다.

• Polymer(Korea)
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• v.33 no.5
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• pp.469-476
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• 2009

In this study, biodegradable superporous hydrogels(SPHs) with fast swelling and superabsorbent properties were prepared using biodegradable crosslinkers and their physicochemical properties were characterized. A biodegradable crosslinker (PLA-PEG-PLA DA) was synthesized by a ring opening polymerization of D,L-lactide (LA) using hydrophilic poly(ethylene glycol) as a macroinitiator, followed by diacrylation of the end groups for the introduction of polymerizable vinyl groups. Various kinds of hydrogels with different chemical compositions were prepared and characterized in terms of swelling ratio, swelling kinetics, and biodegradation properties. The synthetic results were confirmed by $^1H$-NMR, FT-IR and GPC measurements, and the porous structures of the prepared SPHs and their porosities were identified by a scanning electron microscope and mercury porosimetry, respectively. The physicochemical properties of SPHs could be controlled by varying their chemical compositions and their cytotoxicity were found to be very low by MTT assay.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.2
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• pp.97-106
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• 2023

In this study, we would like to study the stabilization of the high content of ceramide formulation by containing cyclodextrin. Ceramide, which constitutes the intercellular lipid, a human skin barrier, is a very important ingredient in moisturizing maintenance by protecting moisture in the skin and strengthening the skin barrier. However, since ceramide is poorly soluble, even if it is included in the cosmetic formulation, it has a problem that it is slowly gelled or crystallized and deposited over time, making it difficult to containing a high amount of ceramide. Cyclodextrin is a cyclic oligosaccharide connected with glucose molecules and has a cylindrical structure with hydrophilic outer surface and hydrophobic inner surface, which is known to improve the physicochemical properties of drugs such as improving solubility and absorption of poorly soluble drugs. We demonstrated the stability of the formulation containing high amount of ceramide by measuring hardness and observing emulsion drops with polarized microscope. This study also demonstrated that the high-content ceramide formulation containing cyclodextrin has the effect of preventing gelation or crystallization of ceramide, thus having excellent environmental conditions stability and skin moisturization.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.132-139
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• 2005

The major obstacle in the popularization of Chungkookjang is the short shelf-life of $2{\sim}3$ months and some problems concerning storage including the growth of molds even in the products even within shelf-life. To solve these problems we conducted a research to improve its storage by using the vacuumed packaging and sanitary method through seed culture, innoculation and sterilization. For the optimization of storage time, temperature and sterilization temperature, we measured viable cell numbers of bacteria and fungi, amount of gas outbreak and contents of amino type nitrogen and monitored these experimental results by response surface methodology of SAS program, so that we could observe the quality changes of Chungkookjang during shelf-life. Especially fungi, which are the biggest troublemaker in Chungkookjang shelf-life, couldn't be detected from the generally and vacuum-packed samples; also, viable cell numbers were highly influenced by sterilization temperature and in vacuum-packed samples. In the case of vacuum-packed samples, amount of gas outbreak was highly influenced by sterilization temperature of its storage conditions and it was higher in generally packed samples as compared to vacuum-packed samples even at any storage conditions. The changes of pH in generally and vacuum-packed samples were highly influenced by the storage temperature. As the temperatures of storage and sterilization were higher and the storage time was longer, so the amount of gas outbreak was accordingly lower. These results showed that amino type nitrogen contents in generally and vacuum-packed samples were systematically influenced by the temperature, storage time and sterilization temperature. Also the result showed that the change of amino type nitrogen contents during storage was less in vacuum-packed samples than in general ones. Based on the above results, we can produce Chungkookjang products with extended shelf-life of as far as 6 months without any quality change using sanitary manufacturing method, vacuumed packaging condition, sterilization in $70^{\circ}C$ for 60 minutes and storage under $10^{\circ}C$ during shelf-life. According to this research, we have the possibility to greatly increase the goods value of Chungkookjang by developing the manufacture processing and packaging.

• Parasites, Hosts and Diseases
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• v.30 no.2
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• pp.65-74
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• 1992

The tegumental ultrastructure of juvenile and adult Echinostoma cinetorchis (Trematoda: Echinostomatidae) was observed by scanning electron microscopy. Three-day (juvenile) and 16-day (adult) worms were harvested from rats (Sprague-Dawley) experimentally fed the metacercariae from the laboratory-infected fresh water snail, Hippeutis cantori. The worms were fifed with 2.5% glutaraldehyde, processed routinely, and observed by an ISI Korea DS-130 scanning electron microscope. The 3-day old juvenile worms were elongated and ventrally curved, with their ventral sucker near the anterior two-fifths of the body. The head crown was bearing 37∼38 collar spines arranged in a zigzag pattern. The lips of the oral and ventral suckers had 8 and 5 type II sensory papillae respectively, and bewteen the spines, a few type III papillae were observed. Tongue or spade-shape spines were distributed anteriorly to the ventral sucker, whereas peg-like spines were distributed posteriorly and became sparse toward the posterior body. The spines of the dorsal surface were similar to those of the ventral surface. The 16-day old adults were leaf-like, and their oral and ventral suckers were located very closely. Aspinous head crown, oral and ventral suckers had type II and type III sensory papillae, and numerous type I papillae were distributed on the tegument anterior to the ventral sucker. Scale-like spines, with broad base and round tip, were distributed densely on the tegument anterior to the ventral sucker but they became sparse posteriorly. At the dorsal surface, spines were observed at times only at the anterior body. The results showed that the tegument of E. cinetorchis is similar to that of other echinostomes, but differs in the number and arrangement of collar spines, shape and distribution of tegumenal spines, and type and distribution of sensory papillae.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.554-562
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• 2003

Xylitol has been used as sugar substitute to prevent dental caries. It is not fermented by most dental plaque bacteria and interferes with the growth of mutans streptococci. Therefore the production of acidic metabolites and the growth of mutans streptococci are inhibited. S. mutans strains which are inhibited to grow under the presence of xylitol are referred as xylitol-sensitive ($X^S$) strains. However, experimental and clinical studies have shown that there were mutated groups of S. mutans strains that are not affected by xylitol. They are referred as xylitol-resistant($X^R$) strains. The aim of the present study was to investigate that emergence of $X^R$ strain would effect on the anticariogenecity of xylitol by comparing the growth rate, the extracellular pH, hydroxyapatite adhesion and the agglutination of the $X^R/X^S$ strains. Overall we came out with following results : 1. No difference in the growth rate and the extracellular pH was found between the $X^S$ strain and the $X^R$ strain. 2. No difference in adhesion to hydroxyapatite surface was found between the $X^R$ strain and the $X^S$ strain (p>0.05) and adhesion of the $X^S$ strain was greater than that of $X^R$ strain in the sucrose-dependent adhesion to hydroxyapatite (p<0.05). 3. The $X^R$ strain was agglutinated in the lower concentration of saliva than that of $X^S$ strains.

• The Korean Journal of Pharmacology
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• v.23 no.2
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• pp.101-111
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• 1987

We investigated the binding properties of $(^3H)$ QNB and $(^3H)$ NMS to mAchR to elucidate the characterstics of mAchR in rat brain by using two different preparations (homogemates & intact brain cell aggregates). The binding properties of both ligands demonstrated high affinity and saturability in both experiments, however $(^3H)$ QNB showed a significantly higher maximal binding capacity than tha ot $(^3H)$ NMS 1. In rat brain homogenates; Displacement of both lignands with several mAchR antagonists resulted in competition curves in accoradnce with the law of massaction for QNB, atropine & scopolamine in thie preparation, also a similar profile was found for the quaternary ammonium analogs of atropine & scopolamine (methyl atropine & methylscopolamine) when $(^3H)$ NMS was used to label the receptors in rat brain. But when these hydrophillic antagonists were used to displace $(^3H)$ QNB, they showed interaction with high- and low-affinity binding sites in brain homogenates. Pirenzepine, the nonclassical mAchR antagonist, was able to displace both ligands from binding sites in this preparation. 2. In intact rat brain cell aggregates; Intact bain cell aggregates were used to elucidate the binding characteristics of $(^3H)$ NMS to mAchR in rat. The magnitude of binding of this ligand was related linearly to the amount of cell protein in the binding assay with a high ratio of total to nonspecific binding. mAchR antagonists displaced specific $(^3H)$ NMS binding according to the law of mass-action, while it was possible to resolve displacement curves using mAchR agonist into high-& low-affinity component. 3. Our results indicate that more hydrophilic receptor ligand $(^3H)$ QNB, displacement experiments in both tissues demonstrated that the lipid solubility of a particulr mAchR ligand might play an important role in determining its profile of binding to the mAchR, and the concentrations of mAchR in rat brain are both on the cell surface (membrane-bound receptor) and in the intracelluar membrane (intermembrane-bound receptor). 4. The results are discussed in terms of the usefulness of dissociated intact rat brain cells in studying mAchR in central nervous system.