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류현규,정인화 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
1,1-Difluoro-1,3-butadienes are useful building blocks for the introduction of difluoromethylene(CF2) and monofluoromethane(CFH) unit into organic molecules. Reaction of 2,2-difluoro-1-iodoethenyl p-toluenesulfonate 1 with 2 equiv of arylboronic acid in the presence of Pd(OAc)2 and Na2CO3 in MeOH at room temperature provided 2,2-difluoro-1-arylethenyl p-toluenesulfonate 2 in good yields. Further cross-coupling reaction of 2 with alkenylboronic acids in the presence of Pd(OAc)2 and K3PO4 in dioxane:H2O(20:1) at 100℃ afforded the corresponding 1,1-difluoro-2-aryl-1,3-butadiene 3 in good yields. The scope and limitation of these reactions will be presented.
류현규,최대섭,조수범,신화선,최호철,정보슬,서혜민,조재민 대한자기공명의과학회 2015 Investigative Magnetic Resonance Imaging Vol.19 No.3
Purpose: The purpose of this study was to evaluate the associated brain parenchymalabnormalities of developmental venous anomalies (DVA) with susceptibility-weightedimage (SWI). Materials and Methods: Between January 2012 and June 2013, 2356 patientsunderwent brain MR examinations with contrast enhancement. We retrospectivelyreviewed their MR examinations and data were collected as per the following criteria:incidence, locations, and associated parenchymal signal abnormalities of DVAs onT2-weighted image, fluid-attenuated inversion recovery (FLAIR), and SWI. Contrastenhanced T1-weighted image was used to diagnose DVA. Results: Of the 2356 patients examined, 57 DVAs were detected in 57 patients(2.4%); 47 (82.4%) were in either lobe of the supratentorial brain, 9 (15.7%) were inthe cerebellum, and 1 (1.7%) was in the pons. Of the 57 DVAs identified, 20 (35.1%)had associated parenchymal abnormalities in the drainage area. Among the 20 DVAswhich had associated parenchymal abnormalities, 13 showed hemorrhagic foci onSWI, and 7 demonstrated only increased parenchymal signal abnormalities on T2-weighted and FLAIR images. In 5 of the 13 patients (38.5%) who had hemorrhagicfoci, the hemorrhagic lesions were demonstrated only on SWI. Conclusion: The overall incidence of DVAs was 2.4%. Parenchymal abnormalitieswere associated with DVAs in 35.1% of the cases. On SWI, hemorrhage wasdetected in 22.8% of DVAs. Thus, we conclude that SWI might give a potential forunderstanding of the pathophysiology of parenchymal abnormalities in DVAs.
Biological and phsical evaluation of 7-Dehydrocholesterolpalmitate
류현규,원성용,정인화,방성식,허남,정봉열 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
7-Dehydrocholesterol (7-DHC) is a provitamin of vitamin D3 (cholecalciferol) and can convert to D3 inside the skin by sunlight and heat. 7-DHC has been applied as a material of functional cosmetics having strong function of wrinkle improvement, antioxidant and protective effect of ultraviolet rays, and also showed the possibility as medicine for treatment of osteoporosis due to high production of D3 and childhood atopic dermatitis. However, 7-DHC is very unstable against light source except skin and thus decrese the activity. Although several studies to overcome the unstability of 7-DHC have been carried out, the study on the stability of 7-DHC has been quite limited. Herein, we wish to report on the synthesis of relatively stable 7-DHC. Palmitate to solve the drawbacks of 7-DHC and their properties such as wrinkle improvement, better skin absorption and antioxidant.
RF용 Silicon MOSFET 등가회로 모델의 변수추출에 관한 연구
이성현,류현규 대한전자공학회 1997 電子工學會論文誌, D Vol.d34 No.12
An accurate extraction technique is developed to determine full euqivalent circuit parameters of Si MOSFETs using 1 set of measured S-parametes without complicated optimization process. This technique is based on the use of anlytic Z-parameters experessions for resistances and inductances and the Y-parameter ones for ntrinsic parameters. This accuracy is proved over the wide range of gate voltage by observing good agreement between measured and fitted Z-parameter equations and frequency-independent response of the extracted intrinsic parameters. Using this technique, gate voltage-dependencies of model parameters are obained in the saturation region and these results show the similar behavior to the short-channel effects expected from the device theory.
PEG 결합체를 가진 비타민C 유도체와 7-DHC 복합비타민의 합성
이휘조,류현규,정인화,방성식,허남,정봉열 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
7-DHC(7-Dehydrocholesterol)와 비타민 C는 항산화 기능을 가지는 기능성 화장품 재료로 사용되어져 왔다. 하지만 두 비타민은 햇빛과 열에 의한 불안정성과 피부의 흡수에 어려움을 가지고 있다. 이형비타민을 동시에 결합한 PEG 결합체는 생체 친화적 결합체로서 독성 감소, 수용성 및 안정성 증가 효과를 가져올 수 있다. 본 연구에서는 7-DHC와 비타민 C 유도체를 PEG에 결합체에 결합시킨 이형복합체를 합성하여 각각의 문제점을 해결하고자 하였다. 7-DHC succinate 1을 tetraethyleneglycol과 반응시켜 7-DHC SA TEG 2 를 합성하고 이를 succinic anhydride와 반응시켜 7-DHC TEG succinate 3 을 합성한다. 한편 비타민 C(ascorbic acid)의 5,6 그리고 3 hydroxyl group을 acetone과 ethylbromide로 각각 protecting한 화합물 4를 합성한다. 마지막으로 앞에서 합성된 화합물 3과 화합물 4를 EDC와 DMAP 존재하에서 반응시키면 PEG 결합체를 가진 7-DHC와 protected 비타민C의 이형복합체 5가 좋은 수율로 합성되어진다.
PEG 결합체를 가진 비타민E와 7-DHC 복합비타민의 합성
이휘조,류현규,정인화,방성식,허남,정봉열 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
7-DHC(7-Dehydrocholesterol)와 비타민E는 항산화 기능을 가지는 기능성 화장품 재료로 사용되어져 왔다. 그러나 7-DHC와 비타민E는 햇빛과 열에 의한 불안정성과 피부의 흡수에 어려움을 가지고 있다. 이형비타민을 동시에 결합한 PEG 결합체는 생체친화적 결합체로서 두 비타민의 기능적인 문제점을 해결하여 독성 감소 뿐만 아니라 수용성 및 안정성 증가 효과를 가져올 수 있다. 본 연구에서는 7-DHC와 비타민E를 PEG 결합체에 결합시킨 이형복합체를 합성하여 각각이 가지는 문제점을 해결하고자 하였다. 먼저 비타민E(tocopherol)를 succinic anhydride와 반응시켜 tocopherol succinate 1을 합성한다. 화합물 1을 tetraethyleneglycol과 반응시켜 tocopherol succinate tetraethyleneglycol 2를 합성한다. 한편 7-DHC를 succinic anhydride와 반응시켜 7-DHC succinate 3을 합성한다. 마지막으로 앞에서 합성된 화합물 2와 화합물 3을 EDC와 DMAP 존재하에서 반응시키면 PEG 결합체를 가진 7-DHC와 비타민E의 이형복합체 4가 좋은 수율로 합성되어진다.