• 한국응용과학기술학회지
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• 제27권4호
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• pp.391-398
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• 2010

Soybean lecithin liposomes composed phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidic acid were prepared by using the previously developed supercritical reverse phase evaporation method. The effect of phospholipid composition on the formation of liposomes and physicochemical properties were examined by means of trapping efficiency measurements, transmission electron microscopy, dynamic light scattering and zeta potential measurements. The trapping efficiency of liposomes for D-(+)-glucose made of CNA-Ⅰ which contains approximately 95% phosphatidyl choline is higher than that of CNA-II and CNA-O which contain approximately 32% phosphatidyl choline. However there is no any difference between the trapping efficiency of liposomes for D-(+)-glucose made of CNA-II which has saturated hydrocarbons tails and that of liposomes made of CNA-O which has unsaturated hydrocarbon chains. The electron micrographs of liposomes made of CNA-II and CNA-O show small spherical liposomes with diameter of $0.1\sim0.25{\mu}m$, while that of CNA-I shows large unilamellar liposomes with diameter of $0.2\sim1.2{\mu}m$. These results clearly show that phospholipid structure of phosphatidylcholine allows an efficient preparation of large unilamellar liposomes and a high trapping efficiency for water soluble substances. Liposomes made of CNA-II and CNA-O remained well-dispersed for at least 14 days, while liposome suspension made of CNA-I separated in two phase at 14 days due to aggregation and fusion of liposomes. The dispersibility of liposomes made of CNA-I is lower than that of CNA-II and CNA-O due to the smallar zeta potential of CNA-I.

• Restorative Dentistry and Endodontics
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• 제16권2호
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• pp.18-32
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• 1991

The purpose of this study was to observe characteristic properties of amalgam through the polarization curves and SEM images from 4 type amalgams (Amalcap, Shofu spherical. Dispersalloy and Tytin) with 3 different surface finish procedures (polishing, burnishing and carving) by using the potentiostats (EG & GPARC) and SEM (Jeol JSM-35). After each amalgam alloy and Hg was triturated as the direction of the manufacturer by means of mechanical amalgamator (Samki), the triturated mass was inserted into the cylndrical metal mold which was 12 mm in diameter and 10 mm in height and was pressed with $100kg/cm^2$. 4 specimens of each type amalgam were burnished with egg burnisher and another 4 specimens of each type amalgam were carved with Hollenback carver. Above 8 specimens and remaining untreated 4 specimens were stored at room temperature for about 7 days. Untreated 4 specimens of each type amalgam were polished with abrasive papers (Deer) from #400 to #1200 and finally on the polishing cloth with $0.5{\mu}m$ and $0.06{\mu}m$ $Al_2O_3 $ powder suspended water. Anodic polarization measurements was employed to compare the corrosion behaviours of the amalgams in 0.9% saline solution at $37^{\circ}C$. The open circuit potential was determined after 30 minutes immersion of specimen in electrolyte. The scan rate was 1 mV/sec and the surface area of amalgam exposed to the solution was $0.64cm^2$ for each specimen. All the potentials reported are with respect to a saturated calomel electrode (SCE). SEM images of each specimen were taken after + 800 mV (SCE) polarization. The results were as follows: 1. The corrosion potential of high copper amalgam was more anodic than that of low copper amalgam. 2. The polished amalgam were more resistant to corrosion than any other burnished and carved amalgam. 3. In the case of polishing, current density of high copper amalgam was lower than that of low copper amalgam.

• 한국지반공학회지:지반
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• 제13권4호
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• pp.95-108
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• 1997

피에조 콘의 소산시험을 이용한 정규 압밀 지반의 압밀계수 추정은 그간 많은 연구자들에 의하여 연구되어 왔으나 각 연구자들의 가정 사항과 해석 방법에 따라 특정한 압밀도에 대해서도 매우 넓은 범위의 이론적인 해들이 제시되어 왔다. 본 연구에서는 보다 현실적이면서 전 범위의 압밀도에 걸쳐서 일관성 있는 압밀계수를 구할 수 있도록 최적화 기법을 적용하였다. 콘 관입효과를 고려하기 위해 연속적인 구형 공동확장을 적용하므로써 이론적으로 얻어지는 간극수압의 분포와 관입 간극수압으로부터 초기 과잉간극수압의 분포를 결정하였으며 축대칭 선형비혼합 압밀이론을 사용하여 유발된 과잉간극수압의 소산효과를 모사하였다. 이와 같이 계산된 소산곡 선과 실제 계측된 소산곡선의 차이를 최소화시키기 위하여 비구속 최적화 알고리듬인 BFGS가 사용되었고 golden section 일차원 탐색법이 사용되었다. 검증 예제를 통하여 적용된 최적화 기법의 안정된 수렴성을 확인하였고 실제 예제에 적용함으로써 제안된 방법이 넓은 범위의 압밀도 범위에서 계측된 소산곡선과 잘 일치하는 압밀계수를 산정함으로써 매우 효과적임을 확인 할 수 있었다.

• 폴리머
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• 제36권5호
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• pp.628-636
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• 2012

폴리(비닐 알코올)(PVA)/디메틸설폭사이드 용액에 폴리스티렌 라텍스 구형입자(직경 범위: 100~300 nm)를 소량 첨가한 뒤, 구형 입자 표면에 형성된 사슬 배제층 두께가 사슬의 농도에 따라 어떻게 의존하는지를 동적 광산란법으로 조사하였다. 묽은 용액 농도에서는 배제층의 두께가 PVA 사슬의 회전반경의 $63{\pm}3%$ 수준에서 일정하게 유지되었었으나 준희박 용액 농도의 초기 영역인 $1.5{\leq}C[{\eta}]{\leq}3$ 범위에서는 배제층 두께 ${\delta}$의 고분자 농도 의존성은 이론치 -0.75와 비슷한 ${\delta}{\sim}C^{-0.8}$로 얻어졌다. 보다 높은 농도 $C[{\eta}]$ >3 이상에서는 배제층의 두께가 급격히 감소하는 것으로 나타났는데 그 이유는 탐침입자간 Oosawa 인력에 의하여 유발된 응집효과가 그 원인인 것으로 설명할 수 있었다.

• Restorative Dentistry and Endodontics
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• 제13권2호
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• pp.221-235
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• 1988

The purpose of this study was to observe characteristic properties through the polarization curves and EMPA images from 4 different types of amalgam obtained by using the potentiostats (EG & G PARC) & EPMA (Jeol JSM-35), to investigate the degree of corrosion of each phase of amalgam on the oxidation peak, and to identify corrosion products from the corroded amalgam by use of X-ray diffractometer(Rigaku). After each amlgam alloy and Hg were triturated as the direction of the manufacturer by means of the mechanical amalgamator(Shofu), the triturated mass was inserted into the cylindrical metal mold which was 12mm in diameter and 10mm in height and was condensed by means of routine manner. The specimen was removed from the mold and stored at room temperature for about 7 days. The standard surface preparation was routinely carried out. Anodic polarization measurement was employed to compare the corrosion behaviours of the amalgams in 0.9% saline solution(pH6.8~7.0) and artificial saliva (pH6.8~7.0) at $37^{\circ}C$. The open circuit potential was determined after 30 minutes' immersion of specimen in electrolyte and the potential scan was begun at the potential of 100mV cathodic from the corrosion potential. The scan rate was 1mV/sec and the surface area of amalgam exposed to the solution was 0.64$cm^2$ for each specimen. All the potentials reported are with respect to a saturated calomel electrode (SCE). EPMA images on the determined oxidation peaks of each amalgam in artificial saliva were observed. X-ray diffraction patterns of each sample were recorded before and after polarization in artificial saliva (Aristaloy, Caulk Spherical, Dispersalloy and Tytin: at +770mV, +585mV, +8.10m V and +680m V respectively) by use of a recording diffractometer. Nickel filtered Cu $K_{{\alpha}_1}$ radiation was used and sample was scanned at $4^{\circ}(2{\theta})/min.$ from $25^{\circ}$ to $80^{\circ}$. The following results were obtained. 1. Oxidation peak potential in artificial saliva shifted to more anodic direction than that in saline solution. 2. The corrosion potential of high copper amalgam was more anodic than the potential of low copper amalgam. 3. The current density was lower in artificial saliva than in saline solution. 4. One of the corrosion products, AgCl was identified by X-ray diffraction analysis. 5. ${\gamma}_2$ phase was the most susceptible to corrosion and e phase was stable in low copper amalgam and ${\eta}$' phase and Ag-Cu eutectic were susceptible to corrosion in high copper amalgam.

• 한국의상디자인학회지
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• 제17권1호
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• pp.141-154
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• 2015

The purpose of this study is to look for a development plan for strategic brand logo by a means of scrutinizing general characteristics and trend in the visual properties of outdoor logo brands. In this study, data research and analysis were conducted over the 68 outdoor brands in circulation in the domestic market based on the information on the website of each brand in order to examine the visual characteristics of an outdoor brand logo. For this, it was performed to examine the desired brand concept of each brand and to analyze the visual characteristics of typeface, color, and type of logo. The results of this research are the followings: First, it was found that the most popular typeface in outdoor brand logos is a capitalized Gothic type. It seems that the logo type is designed to symbolize power, toughness, and masculinity and to express the concept of sportswear brand. Second, when it comes to color, black color tone appeared most frequently, and also reddish colors among chromatic colors were prevailing over others like green, blue, or yellow. It is believed that reddish colors were used to express passion, power, youthfulness, and energy; black color tone for tough, masculine power. Third, the logo symbol of outdoor brands mostly contains mountain, the heads of powerful animals, spherical shape/abstract image that embodies outdoor sports activities. It was analyzed that these resulting symbols were chosen to convey the images of nature, conquest, challenge, future, and passion that are the brand concept of most outdoor brands. Today, in our country, the logo of an outdoor brand is the important factor that symbolizes the brand concept, function, or characteristics. Therefore, the necessity of constant follow-up researches is required to devise the way of designing the brand logo that can build brand power and enhance brand image.

• 한국세라믹학회지
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• 제41권10호
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• pp.766-770
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• 2004

구형 실리카 나노 콜로이드 입자를 이용하여 반사방지막을 제조하였다. 실리카 콜로이드 현탁액을 모세관 힘을 이용하여 기울어진 두 장의 유리판 사이에 저장한 후 위의 유리를 이동시켜 반사 방지막을 코팅하였다. 상판 유리의 이동속도가 빨라질수록 막의 두께는 감소하였고, 막의 두께 변화에 따라 광 투과율이 변하였다. SEM으로 관찰된 실리카 나노 입자는 최밀충진에 가깝게 유리 기판에 부착되어 있었으며, 이로부터 고체 입자와 기공을 포함하는 막의 유효 굴절율을 구하였다. 최대의 광투과율을 나타내는 파장과 유효 굴절율로 부터 계산한 막의 두께는 SEM 사진 및 profiler로 구한 값과 잘 일치하였다. $94.7\%$의 최대 광투과율을 얻었으며, 양면으로 코팅한다면 $97.4\%$의 투과율 즉 $1.3\%$의 반사율을 얻을 수 있는 것으로 나타났다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7473-7482
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• 2013

The G-protein coupled receptor 87 (GPR87) is a recently discovered orphan GPCR which means that the search of their endogenous ligands has been a novel challenge. GPR87 has been shown to be overexpressed in squamous cell carcinomas (SCCs) or adenocarcinomas in lungs and bladder. The 3D structure of GPR87 was here modeled using two templates (2VT4 and 2ZIY) by a threading method. Functional assignment of GPR87 by SVM revealed that along with transporter activity, various novel functions were predicted. The 3D structure was further validated by comparison with structural features of the templates through Verify-3D, ProSA and ERRAT for determining correct stereochemical parameters. The resulting model was evaluated by Ramachandran plot and good 3D structure compatibility was evidenced by DOPE score. Molecular dynamics simulation and solvation of protein were studied through explicit spherical boundaries with a harmonic restraint membrane water system. A DRY-motif (Asp-Arg-Tyr sequence) was found at the end of transmembrane helix3, where GPCR binds and thus activation of signals is transduced. In a search for better inhibitors of GPR87, in silico modification of some substrate ligands was carried out to form polar interactions with Arg115 and Lys296. Thus, this study provides early insights into the structure of a major drug target for SCCs.

• 대한수의학회지
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• 제33권4호
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• pp.573-577
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• 1993

청설모(Sciurus vulgaris corea)의 췌장에 분포하는 glucagon 및 somatostatin 세포의 분포와 그들 분비과립의 특징을 밝히기 위해 면역조직화학적 및 면역전자현미경적 방법으로 관찰하였다. Glucagon 면역반응세포는 주로 췌도의 주변부에 분포하였고, 때로는 외분비부에서 관찰되었다. 이 세포의 분비과립은 직경이 240~320nm였으며, 전자밀도가 높은 core를 전자밀도가 낮은 halo가 둘러싸고 특히 gold particle들은 전자밀도가 높은 core에 강한 반응을 보였다. Somatostatin면역반응세포는 췌도의 주변부를 따를 면역반응이 아주 약한 세포들로 산재하였으며 또한 외분비에서 단독 혹은 소집단으로 관찰되었다. 이 세포의 분비과립은 전자밀도가 낮고 직경이 250~275nm였으며, gold particle는 분비과립에 중등도로 고른 반응을 보였다.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.471-478
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• 2013

PURPOSE. The aim of the study was to evaluate the effect of annealing on the nanostructure and hardness of Co-Cr metal ceramic samples that were fabricated with a direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Five groups of Co-Cr dental alloy samples were manufactured in a rectangular form measuring $4{\times}2{\times}2$ mm. Samples fabricated by a conventional casting technique (Group I) and prefabricated milling blanks (Group II) were examined as conventional technique groups. The DMLS samples were randomly divided into three groups as not annealed (Group III), annealed in argon atmosphere (Group IV), or annealed in oxygen atmosphere (Group V). The nanostructure was examined with the small-angle X-ray scattering method. The Rockwell hardness test was used to measure the hardness changes in each group, and the means and standard deviations were statistically analyzed by one-way ANOVA for comparison of continuous variables and Tukey's HSD test was used for post hoc analysis. P values of <.05 were accepted as statistically significant. RESULTS. The general nanostructures of the samples were composed of small spherical entities stacked atop one another in dendritic form. All groups also displayed different hardness values depending on the manufacturing technique. The annealing procedure and environment directly affected both the nanostructure and hardness of the Co-Cr alloy. Group III exhibited a non-homogeneous structure and increased hardness ($48.16{\pm}3.02$ HRC) because the annealing process was incomplete and the inner stress was not relieved. Annealing in argon atmosphere of Group IV not only relieved the inner stresses but also decreased the hardness ($27.40{\pm}3.98$ HRC). The results of fitting function presented that Group IV was the most homogeneous product as the minimum bilayer thickness was measured (7.11 ${\AA}$). CONCLUSION. After the manufacturing with DMLS technique, annealing in argon atmosphere is an essential process for Co-Cr metal ceramic substructures. The dentists should be familiar with the materials that are used in clinic for prosthodontics treatments.