• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.731-735
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• 2008

The fluid ensemble in the liquid lens, which is composed of electrolyte and silicone oil, is the key material system to vary the focal length processing of the electrochemical desorption. In order to characterize the capability of the liquid lens according to response time and optical range, we prepared a fluid ensemble comprising the electrolyte and oil. To elucidate the physical mechanism of the effective response time, we examined the viscosity dependency while satisfying the requirements for the density and refractive index of the electrolyte and oil, respectively. The characterization results indicated that the response time (up and down) is influenced by the viscosity of the electrolyte and oil. On this basis, we prepared a fluid ensemble capable of reversibly adjusting for the focal length of the liquid lens, as well as the response time. The ensemble is applicable to various systems such as micro-lens and optical sensors.

• Tuberculosis and Respiratory Diseases
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• v.40 no.5
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• pp.610-615
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• 1993

Silicone (polydimethylsiloxane) has widely been used in breast augmentation and other cosmetic procedures. Despite the stability of its chemical nature, local and systemic adverse reactions associated with silicone have been reported. There were several patients who suffered from pulmonary embolism associated with injection of silicone. Silicone-induced pneumonitis and sudden death after subcutaneous injection of silicone has been also described. However, there is no case in the literature of clinically diagnosed silicone-induced pulmonary embolism in Korea. We experienced 2 women who developed respiratory symptoms after illicit subcutaneous injection of silicone for the purpose of colporrhaphy. One patient was admitted because of dyspnea, chest pain, hemoptysis and bilateral pulmonary infiltration after repeated injection of silicone. Pulmonary function test initially showed severe restrictive pattern and transbronchial lung biopsy disclosed numerous oil-like material filling the alveolar septal capillaries and macrophages. High resolution C. T., bronchoalveolar lavage, transbronchial lung biopsy and pulmonary angiogram disclosed abnormalities compatible with silicone fluid-induced pulmonary embolism. The other patient expired shortly after arrival in the emergency room. It is suggested that illicit injecion of silicone fluid carries serious respiratory problems and can induce pulmonary embolism followed by acute respiratory failure.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1442-1444
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• 2003

폴리머 애자용 shed 재료의 전기방전에 대한 열화내성과 표면이 오염된 조건하에서도 우수한 발수성 유지는 제품의 장기성능에 있어서 가장 중요한 인자들이다. 내트래킹성 확보를 위한 보강재로는 ATH가 주로 사용되고 있으며 ATH의 첨가량이 많을 수록 내트래킹성은 대체로 향상되는 것으로 되어 있다. 그러나 애자 제조시 무결점 성형성의 만족이 대단히 중요하기 때문에 ATH를 고충진하는 경우 사용하는 process oil들의 종류 및 첨가량을 고려한 ATH 첨가량의 최적화는 필요하다. 본 논문에서는 ATH를 170 part로 다량으로 첨가하면서 화학적 구조와 점도가 다른 몇 가지 실리콘 fliud들을 사용하여 무결점 성형에 적합한 가소도를 갖는 컴파운드를 제조하여 기본물성과 초고압 옥외절연물의 shed 재료로서 장기성능에 영향을 주는 방전열화내성과 표면발수성의 회복특성을 평가하였다. 컴파운드의 성형작업성과 관련이 큰 가소도는 fluid 점도에 따라 상당한 차이를 보이므로 실리콘 fluid 종류의 선택과 첨가량의 최적화에는 성형작업성, 발수성 회복특성, 열화내성 등의 고려가 필요하다. 무결점 애자성형을 위한 진공 사출에서 고무 컴파운드의 가소도가 중요한데 동일한 ATH첨가조건에서 일정한 가소도를 갖게 하는데 필요한 양은 fluid들의 종류에 따라서 상당한 차이가 있었다. 코로나 처리후 발수성 회복특성은 fluid들의 분자크기와 반응기의 종류에 따라 상당히 영향을 받았으며 분자가 클수록 초기회복속도는 다소 느렸지만 평상시에 늘 유지되는 상시발수성은 다소 높게 유지되었다. 아크와 트래킹 방전에 의한 무게 감소는 ATH가 과량으로 첨가되어 상당히 적었으며 fluid의 분자가 크면서 페닐기를 가진 fluid들이 첨가된 고무가 우수한 특성을 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.565-569
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• 1999

In these days, the silicone insulators have been increasingly studied and applied for outdoor insulators because it has superior characteristics than porcelain and glass insulators, which have been used for outdoor insulators. First of all, The excellent performance of the silicone rubber in polluted and wet conditions is attributed to the ability of the material to maintain the hydrophobicity of the surface in the presence of severe contamination and wet conditions. This is because of the presence of low molecular weight mobile fluid in the silicone rubber which diffuses to the surface and to above the contamination layer. But, the leakage current and some surface discharge occurs on surface of the composite polymeric insulation materials when the insulator is used for a long time with severe contaminative condition and it can lead the contamination flashover. So the leakage current and the discharge current are important to estimate the condition of the silicone rubber surface. In this paper, the average leakage current, the relation of surface discharge current and phase angle were study to investigate electrical conduction of silicone rubber surface with the salt fog condition.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.866-868
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• 1998

Room temperature vulcanizing(RTV)silicone rubber has been widely used to coat porcelain insulators to render water repellency to prevent formation of water filming on the surface and thus to suppress the leakage current and consequent flashover. However, the electrical property and its hydrophobicity of RTV silicone rubber coating under outdoor conditions may be influenced by many environmental factors. In this study various treatments, such as salt-fog, salt water immerging and UV irradiation were applied to samples for investigation the change of the electrical property and hydrophobicity. As a result the leakage current increased and contact angle decreased as the degradation time longer. But the degraded RTV silicone rubber has recovered its hydrophobicity during the drying time in ambient condition because LMW(Low Molecular Weight)silicone fluid diffused from the bulk to the surface.

• Tuberculosis and Respiratory Diseases
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• v.51 no.2
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• pp.166-172
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• 2001

Silicone fluid is a biomaterial widely used in modern cosmetic procedures because there are few side effects, considerable chemical stability and predictable physical properties. However, many local and systemic adverse reactions have reported. In particular some serious pulmonary complications have been reported such as pulmonary thromboembolism, acute respiratory distress syndrome with some cases leading to mortality. Most of the serious complicated cases were induced by an illegal silicone fluid injection. We experienced two cases of acute respiratory distress syndrome with pulmonary hemorrhage induced by an illegal silicone fluid injection. The patients were 41 & 51 year old women, who complained of dyspnea. The chest X-ray and HRCT scan findings showed a bilateral ground glass attenuation on the bilateral dependent portion of the upper and middle lung zone. The patients clinical symptoms and the radiologic and other laboratory findings were compatible with acute respiratory distress syndrome induced by the silicon fluid injection. Here we report two cases of acute respiratory distress syndrome with pulmonary hemorrhage induced by an illegal silicone injection with a review of the relevant literature.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1204-1208
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• 2000

Objectives : At the closure of the transsphenoidal approach(TSA), the proper sellar floor reconstruction plays an important role in preventing postoperative complications. The septal cartilage, perpendicular plate of nasal septum, and the sphenoid sinus bone are usually used to repair the sellar floor as a bone splint. The authors evaluate the usefulness of a silicone plate as a substitute for bone splint to close a defect of the sellar floor. Materials and Methods : A silicone plate was used to repair the sellar floor in 7 patients with sellar lesions which included four pituitary adenomas, two Rathke's cleft cysts and one metastatic tumor. Among seven cases, five cases underwent a standard TSAs and two received a extended TSAs. The trajectories of the approach were sublabial in four cases and endonasal routes in three cases. The silicone plate for implantation was cut to a size of slightly larger than that of bone window and inserted with a three-pronged fork, and then adjusted precisely. Results : In six patients, there were no complications which related to sellar floor reconstruction. A postoperative cerebrospinal fluid(CSF) rhinorrhea was observed in one patient with pituitary macroadenoma. Conclusions : From the authors' experience, the advantages of the silicone plate are its simplicity of molding to fit any size of sellar floor defects, and easy detection of previously created bone window at reoperation.

• Tribology and Lubricants
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• v.25 no.3
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• pp.176-181
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• 2009

Aminated polyacrylonitrile as the new organic disperse phases of the anhydrous ER fluid has been synthesized and ER effect of the suspension composed of aminated polyacrylonitrile in silicone oil investigated. The suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 1.6 power on theelectric field. The current density and the conductivity of the of aminated polyacrylonitrile suspension increase with the electric field intensity and moreover the conductivity of the suspension is about 8 order of magnitude higher than that of the silicone oil. On the basis of the the results, aminated polyacrylonitrile suspension showed the ER flow behavior upon application of the electric field due to the polarizability of the branched amine polar group of the aminated polyacrylonitrile particles.

• Elastomers and Composites
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• v.33 no.1
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• pp.37-43
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• 1998

The permeation of gas through polymer membrane at temperatures above its glass transition, generally occurs by a solution-diffusion mechanism. This mechanism is performed by the affinity difference between polymeric materials and gas molecules, and various technologies, such as copolymerization, impregnation and so on, have been researched to improve the affinity of polymeric material for the gases. In this study, permeability and selectivity for some gases were obtained from steady-state rates of gas permeation through silicone rubber membrane which is prepared by supercritical fluid extraction method. The permeability was measured by the volumetric method proposed by Barrer. Permeability was increased generally with temperature and permeation pressure. Silicone rubber membrane shows a higher permeability to $CO_2$ than to $O_2$, $N_2$. This results probably reflect the relatively high solubility of CO_2 in silicone rubber membrane, which is due to the affinity of $CO_2$ molecules. Since separation powers of $CO_2/N_2$, $CO_2/O_2$ were more than 200, and 100, respectively, it is able to separate $CO_2$ from the air, and the optimum temperature and pres-sure was 328.15 K, 60 cmHg respectively. In future, it is possible that the silicone rubber membrane can be used for separation or concentration of $CO_2$ through experiment for mixed gas separation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.503-506
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• 2004

In this paper we investigated the changes of surface hydrophobic characteristics on silicone rubbers by corona discharge treatment and also investigated the distribution and the behavior of low molecular weight(LMW) silicone fluid which was extracted by solvent-extraction with gel permeation chromatography(GPC). It was shown that contact angle was $110.5^{\circ}$ on initial sample but contact angle was approximately decreased to $10^{\circ}$ after 45 minutes. However the surface hydrophobic characteristic on silicone rubbers which were removed from corona discharge was recovered within 5 hours. It was shown that corona discharge insured the increase of diffusible LMW chains, which could lead to recover the surface hydrophobicity. The surface hydrophobic characteristics on silicone rubbers and the recovery mechanism based on our results were discussed.