• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.799-804
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• 2000

The joint treatment of concrete is one of the technical problems in top down construction method. Joints created wit the top down construction result in serous weakness from the aspects of both structural and water-barrier function. Several case studies for the insepction of top down construction joints of column in SRC structure using radar and infrared thermography method. The advantages and limitations of these methods for non-destructive inspection in top own construction joints are investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.811-816
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• 2000

The joint treatment of concrete is one of the technical problems in top down construction method. Joints created with the top down construction result in serious weakness from the aspects of both structural and water-barrier function. Ultrasonic method was used for the inspection of top down construction joints of column in SRC structure in this study. As a result it has been verified that the semi-direct measurement method is more effective than the other methods for detecting the voids of construction joints.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.395-395
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• 2013

GaN는 LED, 태양전지, 그리고 전자소자 등에 쓰이는 물질로, 관련 연구가 활발히 진행되고 있으며, 이와 더불어 top-down방식을 활용한 소자제작 방법 또한 발달되고 있다. 하지만, 일반적으로 LED 제작에 사용되는 c-plane GaN의 경우, c축 방향으로 발생하는 분극의 영향을 받게되며, 분극은 LED내 양자우물의 밴드를 기울게 하여 전자와 홀의 재결합률을 감소시켜 낮은 내부양자효율을 야기한다. 이러한 문제를 해결하기 위해 여러 가지 방법들이 제시되었으며, 그 중에서도 a면, 혹은 m면과 같은 nonpolar면을 사용하는 GaN LED가 주목받고 있다. 본 연구에서는, top-down방식을 통해 약 $2{\mu}m$ 크기의 diameter를 갖는 micro-sized column LED를 구현하였으며, 식각 후 드러나는 semipolar면을 wet treatment를 통해 제거하여 nonpolar면을 드러나게 하였으며, 이 면에 Ni/Au를 contact하여, 전기적, 광학적 특성을 논하였다. Fig. 1은 I-V 특성 그래프이며, Fig. 2는 EL측정 결과(광학적 특성)이다.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.4
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• pp.290-295
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• 2000

The joint treatment of concrete is one of the technical problems in top down construction method. Joints created with the top down construction result in serious weakness from the aspects of both structural and water-barrier function. Ultrasonic method was used for the inspection of top down construction joints of a various column in SRC structure in this study. The advantages and limitations of this method for non-destructive inspection in top down construction joints are investigated. As a result, it has been verified that the semi-direct measurement method is more effective than the other methods for detecting the voids of construction joints using ultrasonic method.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.321-321
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• 2014

GaN는 LED, 태양전지, 그리고 전자소자 등에 쓰이는 물질로, 관련 연구가 활발히 진행되고 있으며, 이와 더불어 top-down방식을 활용한 소자제작 방법 또한 발달되고 있다. 하지만, top-down공정 시 발생 되는 건식 식각에 의한 소자의 손상이 발생되고, 이로 인하여 누설전류가 발생하는 등 여러 가지 문제점이 발생하고 있다. 특히, top-down에서 널리 사용하는 건식식각을 통한 GaN 식각의 경우, nonpolar 면이 아닌, semipolar 면이 드러나게 되며, 이 면은 건식 식각시 발생하는 손상을 포함하고 있다. 본 연구에서는 이러한 문제를 해결하기 위해서, 약 $2{\mu}m$ 크기의 diameter를 갖는 micro-sized column LED를 제작하고, 건식 식각 이후, KOH surface treatment를 통해 손상된 면을 제거함과 동시에 nonpolar면을 드러내는 실험을 실시하였으며, 더불어 column의 diameter를 줄이는 방법을 논하고자 한다.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.356-362
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• 2020

All the faculties at the prosthodontic department in Kyung Hee University Dental Hospital at Gangdong, have been implementing the Top-Down concept of treatment approach since 2006 in which the outcomes of the last prosthetic treatment are predicted in advance during the treatment planning stage of patients with dental tissue defects. Based on the Top-Down concept, this report is also an example of how the final prosthetic treatment was performed in advance before going into implant surgery for the missing teeth. Among the various methods of connecting implant fixture and restoration, the cement-retained method is relatively simple to manufacture restoration without being constrained by the angle of the implants placed, but difficult to remove remaining subgingival excess cement completely, and to detach it being when necessary. In the report, SB-locking method will be introduced which enables an aesthetic implant restoration without either a screw hole or residual excess cement.

• Clinical and Experimental Pediatrics
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• v.53 no.9
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• pp.830-833
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• 2010

Crohn's disease is characterized by chronic inflammation involving any portion of the gastrointestinal tract. Treating Crohn's disease is a major challenge for clinicians, as no curative therapy currently exists. Pediatric Crohn's disease is characterized by frequent relapses, a wide extent of disease, a high prevalence of extraintestinal manifestations, and a severe clinical course. The classic therapeutic approach is known as the 'step-up' strategy, and follows a progressive course of treatment intensification as disease severity increases. Although this approach is usually effective for symptom control, many patients become either resistant to or dependent on corticosteroids. The efficacy of infliximab suggests that, rather than a progressive course of treatment, early intense induction may reduce complications associated with conventional treatment and improve quality of life. Intensive early therapy with infliximab is known as the 'top-down' strategy. Such therapy offers the potential for altering the natural history of Crohn's disease, and is changing treatment paradigms. However, the relatively new concept of an early aggressive or 'top-down' treatment approach is not yet widely accepted, especially in pediatric patients. The results of our current study demonstrate that early and intensive treatment of pediatric Crohn's disease patients with infliximab, at initial diagnosis, was more effective for maintaining remission and reducing flares.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.1
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• pp.1-11
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• 2018

The emergence of mucosal healing as a treatment goal that could modify the natural course of Crohn's disease and the accumulating evidence showing that biologics are most effective in achieving mucosal healing, along with the success of early treatment regimens for rheumatoid arthritis, have led to the identification of early Crohn's disease and development of the concept of catching the therapeutic window during the early disease course. Thus, an increasing number of pediatric gastroenterologists are adopting an early biologic treatment strategy with or without an immunomodulator. Although early biologic treatment is effective, cost and overtreatment are issues that limit its early use. Currently, there are insufficient data on who will benefit most from early biologics, as well as on who will not need early or even any biologics. For now, top-down biologics should be considered for patients with currently known high-risk factors of poor outcomes. For other patients, close, objective monitoring and accelerating the step-up process by means of a treat-to-target approach seems the best way to catch the therapeutic window in early pediatric Crohn's disease. The individual benefits of immunomodulator addition during early biologic treatment should be weighed against its risks and decision on early combination treatment should be made after comprehensive discussion with each patient and guardian.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.1
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• pp.28-35
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• 2008

Purpose: The aim of this study is to report the efficacy of infliximab, a monoclonal antibody directed against tumor necrosis factor alpha which is used for both treatment of refractory pediatric Crohn disease (CD) and induction of remission. Methods: Among pediatric patients who were diagnosed with CD at Samsung Medical Center between March 2001 and August 2007, a total of 16 patients were given infliximab to treat conventional therapyresistant refractory CD and severe active CD for induction of remission. Patients needing maintenance therapy were treated with an infliximab infusion every 8 weeks, and fistulizing CD patients occasionally received the infusion upon the condition that a fistula developed. The efficacy of treatment was assessed by comparing the Pediatric Crohn Disease Activity Index (PCDAI), Hct, ESR, CRP, and serum albumin levels using paired t-test. Results: The male/female ratio was 13:3, and the median age was 13 years (range, 21 months~15 years). The patients included 7 cases of therapy-resistant refractory CD, 7 cases of severe active CD, and 2 cases of fistulizing CD. Mean PCDAI before infliximab therapy was 34.19${\pm}$14.96, and mean follow-up PCDAI within 2 to 4 weeks after the last infusion was significantly lower, at 6.88${\pm}$10.31 (p=0.000). Hematological markers such as ESR (p=0.000), serum albumin (p=0.016), and CRP (p=0.009) also improved significantly after infusion. Remission was achieved in 2 of 4 patients refractory to conventional therapy. Among 3 steroid-dependent patients, 2 were able to discontinue steroid therapy, and dose reduction was possible in 1 patient. Remission after top-down therapy without prior use of other immunomodulators was achieved in 6 weeks in all 7 of the patients who had severe CD. Nine of ten refractory fistulizing CD patients also showed improvement after infliximab therapy. Conclusion: Infliximab was effective in pediatric refractory CD for induction of remission and maintenance therapy, as well as in severe CD for top-down induction therapy. Furthermore, infliximab has contributed to steroid cessation and dose reduction. Long-term follow-up evaluation is needed to determine safety and efficacy of infliximab in the future.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.127-135
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• 2013

In this study, both pressure drop and microbe-population-distribution were observed while running a novel biofilter system with improved design in which the biofilter system is composed of two, upper and lower biofilters with both equal feed-rates of up-flow and down-flow, respectively. Then they were compared with the pressure drop and microbe-population-distribution observed in a conventional biofilter of the same effective volume with unidirectional flow. The pressure drop-value of biofilter system with improved design turned out to be less at the incipient stage of run or steady-state long term operation by more than 40~80% of that of the conventional biofilter. The microbe-population-distribution was observed to be lower and higher at higher and lower column of biofilter, respectively, for both the conventional biofilter and the biofilter system with improved design. The microbe-media of waste-tire crumb showed much greater CFU counts than GAC. In the biofilter system with improved design, the $bottom{\rightarrow}up$ feeding of waste air showed greater microbe-population growth than the $top{\rightarrow}down$ feeding for both the microbe-media of waste-tire crumb and GAC. However, it was more prominent for the former than the latter. Comparing the microbe-population-distributions of both of the conventional biofilter and the biofilter system with improved design, the microbe-population of latter was distributed ca. 15 and 2.5 times more evenly for GAC and the media of waste-tire crumb, respectively, than that of former.