http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
< 전시-P-63 > 산촉매에 의한 목타르와 포름알데히드 합성 특성
양지욱,권구중,양봉숙,김대영,김진규 한국목재공학회 2018 한국목재공학회 학술발표논문집 Vol.2018 No.1
최근, 탄소 섬유 생산을 위한 전구 물질로 재생 가능한 고분자를 찾기 위한 많은 연구가 진행되고 있다. 재생 가능한 폴리머는 대량생산 가능, 저비용 등 기존 석유화학 원료에 비해 많은 장점을 가지고 있기 때문이다. 이러한 이유로 천연고분자인 리그닌을 탄소섬유의 잠재적 전구물질로 많은 주목을 받고 있다. 그러나 리그닌은 복잡한 화학구조로 인한 어려운 용융방사가 단점이다. 이에 최근 목재탄화시 부산물로 액상 오일형태로 생성되는 목타르가 탄소섬유 전구물질로 활용 가능성에 대해서 검토되고 있다. 목타르는 리그닌의 열분해로 인해 생성된 다량의 페놀화합물들이 함유되어 있기 때문이다. 페놀화합물은 포름알데히드와 산촉매에 의한 축합반응에 의해 페놀수지가 제조된다. 산촉매를 이용한 목타르 페놀수지제조에는 반응온도, 촉매의 양 등이 수지제조에 크게 영향을 끼친다. 본 연구는 전통식 및 기계식 탄화로를 이용하여 목탄 제탄시 부산물로 생성된 목타르를 이용하여 반응온도 및 촉매의 첨가량에 따른 수지의 화학적 구조 및 열적특성에 대해서 검토하였다. 촉매로서는 염산을 이용하였고, 목타르와 포름알데히드 합성시에 oxalic acid를 이용하였다. 또한 목타르와 포름알데히드는 같은 혼합비율로 하였고, oxalic acid와 염산의 첨가비율을 다르게 하여 실시하였다. FT-IR분석에서 목타르와 포름알데히드 함성시 반응온도와 산촉매의 첨가량에 따른 화학적 구조는 특이한 차이는 없는 것으로 나타났다. TG를 이용한 열적 안정성은 반응온도와 촉매의 첨가량에 따라 다소 차이가 있었다. 최종600℃의 조건에서 탄화물 수율을 이용하여 열적 안정성을 검토한 결과, 반응온도가 낮을수록 열적 안전성은 낮았으며, 산촉매의 함량은 낮을수록 높았다. 이러한 특성은 전통식 탄화로에서 생성한 목타르와 기계식 탄화로에서 생성된 목타르에서 비슷한 경향을 보여주었다.
양지욱,박영훈 대한안과학회 2008 대한안과학회지 Vol.49 No.8
Purpose: To report a case of occlusive retinal vasculitis in Churg-Strauss syndrome. Case summary: A-48-year-old man visited our clinic complaining of suddenly decreased visual acuity in the left eye. Two months previously he had an operation for sinusitis, and he had been taking medications for asthma. In the initial examination, his best corrected visual acuity was 0.02 in the left eye. Fundus examination showed whitish, multiple, diffuse ischemic lesions around the posterior pole and slightly engorged retinal veins in the left eye. Fluorescein angiography showed delayed choroidal filling and delayed arteriovenous transit time in the left eye, but no apparently visible obstruction site. The eosinophil count was elevated to 65% in the white blood cell differentiated count, and perinuclear antineutrophil cytoplasmic antibodies (ANCA) with antimyeloperoxidase specificity (MPO-ANCA) was increased, but a chest X-ray was normal. Eosinophil infiltrations in the mucosa of the paranasal sinus were found, and peripheral neuropathy was found in a nerve conduction study. Hence, we diagnosed the patient with Churg-Strauss syndrome accompanied by occlusive retinal vasculitis, and started steroid therapy. Thirty days later after steroid therapy, the best corrected visual acuity of the left eye was 0.4. Conclusions: In patients with occlusive retinal vasculitis, we need to consider systemic diseases, such as Churg-Strauss syndrome. J Korean Ophthalmol Soc 49(8):1335-1340, 2008
양지욱,오태훈,박영훈.Ji-Wook Yang. MD. Tae-Hoon Oh. MD. Young-Hoon Park. MD 대한안과학회 2009 대한안과학회지 Vol.50 No.1
Purpose: We present three cases of atypical Harada's disease that exhibited different clinical courses. Case summary: (Case 1) A 56-year-old male initially presented with typical findings of Harada's disease accompanied by exudative retinal detachment of the left eye. However, he did not show any signs and symptoms of Harada's disease in his right eye for 4 years. (Case 2) A 73-year-old male came to our clinic complaining of decreased visual acuity in both eyes with headache and tinnitus. Fundoscopic findings showed bilateral annular choroidal detachment but no evidence of exudative retinal detachment. The same result was obtained on remission. (Case 3) A 53-year-old female presented with decreased visual acuity in both eyes with headache and tinnitus. Fundoscopic findings showed severe choroidal folds instead of exudative retinal detachment, which was observed in 2 other remissive cases. Conclusions: We report 3 cases of atypical Harada's disease that did not present with bilateral exudative retinal detachment. Ophthalmologists should know that Harada's disease can exhibit diverse clinical courses.
LiBr 수용액으로 용해시켜 제조한 거대억새 홀로셀룰로오스 용해 및 재생 필름특성
양지욱,권구중,황교정,황원중,황재현,김대영 한국펄프·종이공학회 2015 펄프.종이기술 Vol.38 No.1
In this study, dissolution characteristics of 60% LiBr aqueous solution for Miscanthus sinensis holocellulose in accordance with heating time and characteristics of regenerated films were analyzed. Miscanthus sinensis holocellulose was made by peracetic acid method. During the dissolution of 60% LiBr solution for the holocellulose, the dissolution was started from the tip of the cellulose fiber after about 7 minutes, and proceeded as it swollen like a balloon. A lot of Si was identified by analyzing hollocellulose regenerated film through SEM/EDS. Cross section of regenerated film as dissolution time till 40 minutes of dissolution showed multilayered structure and fiber orientation. But after 40 minutes, multilayered structure and fiber orientation was not observed. The crystal structure of the holecellulose was transformed cellulose I into cellulose II. Therefore, dissolution for 20 minutes with 60% LiBr solution in the condition of 190℃ hot plate was shown as an optimum condition to manufacture the holocellulose regenerated film.