• Journal of Pharmaceutical Investigation
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• 제34권6호
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• pp.465-469
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• 2004

Colloidal gold nanoparticles might be of use as nano scale delivery systems of various therapeutic materials in the future. Recent studies have reported the feasibility of colloidal gold nanoparticles as gene delivery systems or protein delivery systems. In this study, we aimed to develop a short-step method useful for screening the optimal coating conditions of colloidal gold nanoparticles with proteins. We observed that colloidal gold nanoparticles have properties of changing its unique color when they were exposed to NaCl solution. Taking advantage of the color changing properties of colloidal gold nanoparticles, we applied the color testing method of colloidal gold nanoparticles solutions for evaluating the protein coating nature. Using bovine serum albumin as a model protein, we tested the protein coating of colloidal gold nanoparticles via the color change upon NaCl addition. The optimal coating concentration and coating conditions of colloidal gold nanoparticles with bovine serum albumin were fixed using the color testing methods. We suggest that the color testing method might be applied to optimize the coating condition of colloidal gold nanoparticles with other therapeutic proteins.

• Macromolecular Research
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• 제11권2호
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• pp.110-114
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• 2003

When using the dipping method for crystal formation, mono-layered colloidal crystal structures depend upon the lift-up rate of a glass substrate. The mono-layered colloidal crystals showed the highest quality when the glass substrate was raised at a rate of 3 mm/min at 25 $^{\circ}C$ in a 1 wt% polystyrene colloidal suspension (ethanol medium). In addition, in order to obtain multiple-layered colloidal crystals, an external electric Held was introduced. Multiple-layered colloidal crystals were successfully obtained via this method. The colloidal particles were well ordered over large areas and assembled into a homogeneous structure.

• Tribology and Lubricants
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• 제28권5호
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• pp.212-217
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• 2012

A modified thermal noise method was proposed to measure the normal spring constants of the colloidal probes for an atomic force microscope. We used commercial tipless cantilevers (length 150, width 30, nominal k 7.4 N/m) and borosilicate spheres with a diameter of 20 to fabricate colloidal probes. The inverse optical lever sensitivity of both the tipless cantilever and colloidal probes were used to measure the normal spring constant of the colloidal probes. We confirmed the accuracy and usefulness of our method by comparing the measurement results with those obtained using the nanoforce calibrator (NFC), which reportedly has an uncertainty of 1.00%. The modified thermal method showed a good agreement (~10% difference) with the NFC, allowing us to conclude that the modified thermal method could be employed for the effective measurement of the normal spring constants of colloidal probes.

• 펄프종이기술
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• 제37권3호
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• pp.33-40
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• 2005

In this study, a nano-colloidal silica sol was applied to control the anti-slip property by spraying on kraft paper. Two kinds of nano-colloidal silica sol which have cationic and anionic charge were applied in kraft paper, and the friction and physical strength properties of kraft paper were investigated. The application of colloidal silica sol on wet web in wet-end process by spraying method was tried to improve the friction property and to avoid the general problems of machine contaminations caused by the scattering of sprayed silica particles in dryer part. The physical properties of sheet were also improved by the application of wet web spraying method, and the optimum conditions of wet web spraying operation were closely related with the conditions of pH and electrical charge of wet web and silica sol.

• Korean Chemical Engineering Research
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• 제49권5호
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• pp.535-540
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• 2011

금속염인 lanthanum nitrate를 증류수에 용해시킨 후 실란커플링제인 ${\gamma}$-glycidyloxypropyl trimethoxysilane과 금속산화물인 colloidal silica를 이 용액에 첨가하여 sol-gel법에 의해 유-무기 혼성 용액을 제조하였다. 또한 spiropyran계 광변색 염료를 용매인 tetrahydrofuran에 용해시킨 후 앞서 제조한 혼성 용액과 혼합하여 광 변색 코팅 용액을 제조하였다. 그 후 기재인 polycarbonate 시트에 코팅시키고 열 경화시켜 광 변색성을 갖는 하드 코팅 막을 제조하였다. 이 과정 중 colloidal silica의 첨가량이 코팅 막의 광변색 특성에 미치는 영향을 조사하였다. Colloidal silica의 첨가량이 증가할수록 코팅 막의 소색속도가 빨라졌으며 연필경도가 증가하였다.

• Tribology and Lubricants
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• 제29권3호
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• pp.160-166
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• 2013

There is an indispensable need for force calibration for quantitative nanoscale force measurement using atomic force microscopy. Calibrating the normal force is relatively straightforward, whereas doing so for the lateral force is often complicated because of the difficulty in determining the optical lever sensitivity. In particular, the lateral force calibration of a colloidal probe in a liquid environment often has a larger uncertainty as a result of the effects of the epoxy, the location of the colloidal particle on the cantilever, and a decrease in the quality factor. In this work, the lateral force of a colloidal probe using a reference cantilever with a known spring constant was calibrated in a liquid environment. By obtaining the spring constant and the lateral sensitivity at the equator of a spherical colloidal particle, the damage to the bottom surface of the colloidal particle could be eliminated. Further, it was shown that the effect of the contact stiffness on the determination of the lateral spring constant of the cantilever could be minimized. It was concluded that this method can be effectively used for the lateral force calibration of a colloidal probe in a liquid environment.

• 공업화학
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• 제17권4호
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• pp.386-390
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• 2006

콜로이드형 실리카는 화학적으로 안정한 무기소재로 비표면적과 표면물성이 우수하여 산업적으로 다양한 용도로 사용하고 있다. 본 연구에서는 sodium silicate로부터 이온교환방법 및 산-중화법을 이용하여 colloidal silica를 제조하고 입자성장인자인 온도, pH, 농도와 aging time을 조절하여 크기를 조정하는 방법을 조사하여 균일한 크기분포를 가진 colloidal silica를 제조하였다. 실리카 졸의 크기와 모양은 TEM 및 dynamic scattering method를 이용하여 측정하였다. 또한 콜로이드의 입자크기에 따른 제타 전위값의 변화, 겔화현상과 그 유변학적 특성을 연구하였다.

• 대한핵의학회지
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• 제3권1호
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• pp.1-12
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• 1969

Liver functions in diffuse parenchymal liver disease such as cirrhosis of the liver depend largely on the effective hepatic blood flow rather than on the individual cell functions. Clinical methods of measuring the hepatic blood flow were developed recently by the application of colloidal disappearance rate. In order to correlate the radiogold disappearance rate to conventional biochemical liver function tests, 21 normal subjects and 80 cases of cirrhosis of the liver were studied with both methods. The results are summarized as following: 1. The validity of external counting method to measure the blood disappearance rate of colloidal radiogold was confirmed by in vitro counting of the serial blood samples. 2. The blood disappearance rate of collidal radiogold was essentially the same. as the liver uptake rate of colloidal radiogold in normal and cirrhotic subjects with various degrees of functional disturbance. And it seemed there was no serious extrahepatic removal of the colloidal radiogold. 3. The disappearance rate of colloidal radiogold was not significantly changed by the posture change, but was enhanced by ingestion of 500 ml of water. 4. The disappearance rate of colloidal radiogold was not influenced by single dose of Telepaque, while BSP retention was increased after Telepaque. 5. The mean disappearance half time of colloidal radiogold in normal subjects was $2.49{\pm}0.391$(S.D.) minutes. The mean normal disappearance rate constant (K value) was $0.285{\pm}0.0428$(S.D.)/minute. 6. The colloidal radiogold disappearance half time was abnormally prolonged (over 3.2 min.) in $87.7{\pm}3.68$(S.D.) % of cirrhotic subjects. 7. In patients of liver cirrhosis the blood disappearance rate of colloidal radiogold correlated well to serum albumin and globulin levels and BSP retention which were considered to reflect functions of hepatic parenchymal cells. There was, however, no correlation between colloidal disappearance rate and thymol turbidity test, serum glutamic pyruvic transaminase, and serm alkaline phosphatase activities. The latters were considered to be associated with the activity of liver disease.

• 한국유변학회:학술대회논문집
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• 한국유변학회 2001년도 Australian-Korean Rheology Conference 2001
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• pp.156.6-157
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• 2001

(No abstract, see full-text)

• 펄프종이기술
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• 제30권2호
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• pp.30-39
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• 1998

Effect of cationic starches and anionic colloidal silica on retention and drainage characteristics of Compozil system was investigated. Depending upon the degree of substitution and molecular weight of cationic starches and morphological characteristics of anionic colloidal silica, retention and drainage properties of Compozil system were significantly influenced. When cationic starch addition level increased above a certain limit retention and stock freeness were decreased. To elucidate this an electrostatic coagulation mechanism occurring between unadsorbed starch molecules and anionic colloidal silica was proposed. Unstructured colloidal silica showed greater improvement in retention than structured colloidal silica. Cationic corn starches with different degree of substitution and molecular weights were prepared and their effect as a constituent of Compozil system was also evaluated. By controlling the molecular weight and degree of substitution of cationic corn starch it was possible to achieve significant improvement in fines retention. Cationic corn starch with higher degree of substitution maintained its retention efficiency even when the stock conductivity was increased. Turbidity measurement technique was found to be a simple and useful method to measure the retention characteristics.