• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.161-167
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• 2011

In this paper, we propose an in-plane switching (IPS) mode for liquid crystal displays (LCDs) that, in principle, is free of retardation of the LC cell. Basically, the optical configuration of the LC cell consists of an A-plate and an LC layer for switching between the dark and bright states. We could achieve a fast response time compared with the conventional in-plane LC cell because the free retardation condition of the proposed LC cell enables us to reduce the cell gap even by quarter-wave retardation without any change of the optimized LC material in the transmissive mode. Experiments for verification of the proposed in-plane switching LC cells have shown a significant reduction of the rising time and falling time simultaneously due to the small cell gap. Furthermore, we also proposed an optical configuration for wide viewing property of the retardation free IPS LCD by applying the optical films. We proved the wide-view property of the retardation free IPS LCD by comparing its optical luminance with the calculated optical property of the conventional IPS LCD.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.365-365
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• 2006

The wavelength dispersion of birefringence (or retardation) is very important property for optical use of polymer films. Birefringence free film and retardation film have been widely used for applications such as liquid crystal display (LCD). In this study, miscible polymer blends which consist of polymers of positive and negative birefringence were found. By operating composition and orientation of molecules in the transparent blend films, the behavior of wavelength dispersion of birefringence (retardation) was controlled. The applicability to wideband birefringence free film and quarter wave (retardation) film was discussed.

• The Journal of Korean society of community based occupational therapy
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• v.1 no.1
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• pp.41-47
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• 2011

Objective : We try to show the necessity of crafts and arts comparing visual perception of autism with that of mental retardation using craft programmes. Methods : We applied a visual perception programme after sorting 10 autism and 10 mental retardation according to criteria. A used craft programmes are consulted and produced by specialist who are applying crafts as treatment or have experienced applying crafts. The items included potter, mobile art, wheat flour kneading, clay, corrugated cardboard work and color mix work. We applied the programmes twice a week during 4 weeks and used motor-free visual perception test-third edition(MVPT-3) to investigate the effect before and after treatments. Results : First, craft programmes had effect on both autism and mental retardation. Second, craft programmes had more effect on mental retardation. Conclusion : We could know that craft programmes influenced on visual perceptional development of autism and mental retardation.

• Journal of Environmental Science International
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• v.14 no.1
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• pp.97-103
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• 2005

Because of the toxicity of hexavelant chromium ion, treatments of metallic surface with chromate compounds to retard corrosion are undesirable for safety control in industrial uses and protection of environment. In this study, we investigated several compounds such as inorganic, organic, and polymer materials in order to sub­stitute the chromate conversion treatment on steel sheet. The corrosion property was investigated in a salt spray tester with 3.5 $wt.{\%}\;NaCI\;at\;35^{\circ}C.$ The results showed that the zirconium/silane/polymer triple coatings on the galvanized steel exhibited a significant retardation of corrosion. Although the multicoating system needs a com­plexed processing, we can confirm a possibility of development of a chromate-free chemical conversion treat­ment for galvanized steel sheet.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.801-807
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• 2003

This work aims the search of environmentally friendly pre-treatment technologies to develop chromate replacements for metal finishing industries due to its toxicological properties. Since the corrosion resistance of steel was strongly related to water permeation, galvanized steel sheets were treated with various hydrophobic silane compounds and water-suspended polymer solution. Also, plasma gas discharge was applied to modify the surface of a polymer coated-steel sheet to be hydrophobic. The surface hydrophobicity of materials was introduced by CF$_3$H plasma exposure. The corrosion property before and after the plasma treatment was investigated in a slat spray tester with 3.5 wt.% NaCl at 35$^{\circ}C$. The results showed that both silane/polymer double coatings and plasma treatment of the galvanized steel exhibited significant retardation of corrosion.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.688-690
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• 1998

직업 선택의 과정에 있어 능력, 적성만큼 중요시 해야 할 것은 그 직업에 대해 흥미도이다. 특히 장애인들의 경우 직업을 준비하는 단계에서부터 어느 영역에 직업적 흥미가 있는가를 파악해야 하는 일은 중요하다. Text, Audio/Voice, Image등 멀티미디어 data를 이용, 흥미와 주의 집중을 높혀 직업적 흥미영역에 대한 정확한 data를 얻을 수 있는 시스템 개발이 필요하다.

• Journal of the Korean institute of surface engineering
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• v.32 no.2
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• pp.134-143
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• 1999

The effects of silicon on galvannealing behavior of interstitial-free (IF) steels were studied. The growth rate of the Fe-Zn alloy layer was retarded as silicon in the steel added. Titanium in steel strongly favors Fe-Zn reaction, in particular outburst structures, whereas silicon inhibit them. Cross-sectional and planar views of galvannealed coatings were investigated to characterize alloy phase development. A possible mechanism to explain the retardation effect of silicon is discussed in terms of concentration on surface and inhibition layer.

• Clinical and Experimental Pediatrics
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• v.51 no.12
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• pp.1355-1358
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• 2008

Wilms' tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is caused by deletion of chromosome 11p13, including the Wilms' tumor (WT1) and aniridia gene (PAX6) loci. Here, we report the first case of WAGR syndrome in Korea; the patient was a 2-year-old girl with bilateral aniridia from birth who presented with abdominal distention and mental retardation. Cytogenetically, she had deletion of chromosome 11p11.2-13. Bilateral Wilms' tumors were successfully treated by chemotherapy and surgery. She has been tumor-free for 19 months off chemotherapy with preserved renal function.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.4
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• pp.209-213
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• 2014

Purpose: Pathologic aerophagia (PA) may lead to bowel perforation or volvulus in mentally retarded patients. The authors investigated the effects of clonazepam on the management of PA in children with severe to profound mental retardation (MR). Methods: This study was undertaken as a retrospective case analysis of 21 PA patients with MR who were followed for over 12 months and diagnosed as having PA. Patients were assigned to two management groups, that is, to a clonazepam randomized open-labeled, treatment group or a reassurance group. The following were recorded and analyzed; age, response, remission rate to clonazepam treatment, and the side effect of clonazepam. It was defined positive response (response+) as being symptom-free for a whole week within 1 month of commencing treatment and remission(+) as being symptom-free for a whole month within 6 months of treatment. Results: The average age of the 21 PA children with MR was 10 years and 13 patients were female. Symptom duration before diagnosis of PA was 7 months. Clinical features of the clonazepam-trial group (n=11) and the reassurance group (n=10) were non-significantly different. Response(+) was achieved by 2 patients (18.2%) in the clonazepamtrial group and by no patient in the reassurance group. Remission(+) was achieved by 6 patients (54.5%) in the clonazepam-trial group and by one patient (10%) in the reassurance group (p=0.040). Conclusion: When PA children with MR with severe bowel distention are considered for surgical treatment to prevent acute abdomen, a trial of clonazepam could be recommended.

• Clinical and Experimental Pediatrics
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• v.61 no.7
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• pp.221-225
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• 2018

Purpose: Congenital hypothyroidism (CH) is the most common endocrine disorder in children. Thyroid hormone deprivation results not only in mental retardation but also growth retardation. This study investigates the final height (FH) in Korean patients with CH detected by newborn screening and examines factors that may affect the FH. Methods: The medical records of Korean CH patients (n=45) were reviewed. The FH was examined and target height (TH) was calculated based on mid-parental height. The FH z score (FHZ) and TH z score (THZ) were computed using the 2007 Korean National Growth Chart. The FHZ and THZ were compared with a Student t test. The impact of the etiology of CH (athyreosis, dyshormonogenesis, ectopic thyoid, hypoplastic thyroid), initial serum thyroid stimulating hormone (TSH) level, initial free thyroxine (T4) level, and time of therapy initiation based on FH was assessed. Results: The mean FHZ was $0.10{\pm}1.01$ for male patients and $-0.11{\pm}1.09$ for female patients. There were no significant differences between FHZ and THZ for both female (P=0.356) and male patients (P=0.237). No significant relationship was found between FH and the etiology of CH, initial TSH level, initial free T4 level, and the time of therapy initiation. Conclusion: Early intervention and satisfactory management do not appear to impede growth in Korean patients with CH. Thus, early detection and proper management of patients with CH detected by newborn screening program are necessary.