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친환경 무기질 고화재를 사용한 무시멘트 황토모르타르의 특성
정용욱,김성현,이동규,Jung, Yong-Wook,Kim, Sung-Hyun,Lee, Dong-Gyu 한국건설순환자원학회 2015 한국건설순환자원학회 논문집 Vol.3 No.4
본 연구에서는 친환경 무기질 고화재를 사용하여 무시멘트 황토모르타르의 유동성과 강도특성 및 내수성과 동결융해 등의 내구 특성을 검토하였다. 실험결과 황토모르타르의 재령 28일 압축 및 휨강도는 마사토와 황토 혼합비율에 관계없이 고화재 치환율이 증가할수록 증가하였고, 고화재 치환율에 관계없이 재령 14일까지의 강도증진효과는 크게 나타났으나 재령 14일 이후 강도증진 효과는 상대적으로 낮아 황토모르타르의 강도발현은 일반 콘크리트의 강도발현보다 빠른 것으로 나타났다. 또한, 고화재 10% 사용 시 평균 휨강도는 1.7MPa로 포장용 콘크리트의 재령 28일 휨강도 4.5MPa 이상을 만족시키지 못하였으나, 고화재 20%에서 약 4.0MPa, 고화재 30%에서 5.3MPa로 근접하거나 높게 나타나, 황토모르타르를 포장용 도로에 적용시 고화재 사용량은 최소 20% 이상 되어야 할 것으로 판단된다. 내수성 실험결과 흡수 건조의 반복은 황토의 혼합비율에 관계없이 질량을 감소시켰으며, 최대길이변화율은 황토 혼합비율과 고화재 치환율이 증가할수록 감소하는 것으로 나타났다. 동결융해 저항성 실험결과 동결융해 300 사이클에서 상대동탄성계수는 고화재 20%에서 75%, 고화재 30%에서 79%로 나타나, 황토모르타르의 상대동탄성계수 60% 이상을 만족시키기 위한 고화재 사용량은 20% 이상이 필요한 것으로 나타났다. This study examined the fluidity and strength properties, water resistance, durability, and freeze-thaw of cementless loess mortar using an eco-friendly hardening agent. The experimental result indicates that 28 days compressive and flexural strength of the loess mortar was increased regardless of the weathered granite soil and loess mixture ratio as the replacement ratio of the hardening agent increases. The strengths were significantly increased until 14 days regardless of the hardening agent, while the effect on the strengths increasement was relatively low after 14 days. Thus, the strength development of loess mortar concrete was found to be faster than that of the normal concrete. In addition, when the hardening agent of 10% was used, the average flexural strength was 1.7MPa which is insufficient compared to the 28-day flexural strength of 4.5MPa for the paving concrete. However, the flexural strengths of the loess mortar concrete using the hardening agents of 20% and 30% were 4.0MPa and 5.3MPa, respectively. Thus, the hardening agent need to be at least 20% so that the loess mortar can be used for paving concrete. The experiment for water resistance shows that the repeated absorption and dry reduced mass regardless of the mixing ratio of the loess. The maximum length change also decreased with increasing the substitution rate loess mixture ratio and the hardening agent. The result of the freeze-thaw resistance test indicates that the relative dynamic modulus of elasticity at 300 cycle freeze-thaw with the hardening agents of 20% and 30% were 75% and 79%, relatively. Thus, the hardening agent of at least 20% is required to obtain the relative dynamic modulus of elasticity of 60% for the loess mortar.
대뇌 기저핵 신경세포에서 Nitric Oxide를 매개로 한 망간의 세포독성
정용욱,배재훈,송대규,박원균,고복현,김두희,신동훈,Jung, Yong-Wook,Bae, Jae-Hoon,Song, Dae-Kyu,Park, Won-Kyun,Ko, Bok-Hyun,Kim, Doo-Hie,Shin, Dong-Hoon 대한예방의학회 1999 예방의학회지 Vol.32 No.4
Objectives:eurotoxicity is mediated by nitric oxide(NO) in the rat primary neuronal cultures and assess the effect of $Mn^{2+}$ on the N-methyl-D aspartate(NMDA) receptors. Methods: We have used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)assay to examine the effect of cytotoxicity of $MnCl_2$ in neuronal cells , NO production was determined by measuring nirites, a stable oxidation product of NO. The neurons in the rat that contains neuronal nitric oxide synthase(nNOS) were examined by immunofluorescence and confocal microscopy. The effects of $Mn^{2+}$ on the NMDA receptors was assesed by the whole cell voltage clamp technique. Results: We showed that the NO release and NOS expression was increased with 500uM $MnCl_2$ treatment and an NOS inhibitors, $N^G-nitro-L-arginine$, prevented neurotoxicity elicited by manganese. In the electrophysiological study, $Mn^{2+}$ does not block or activate the NMDA receptors and not pass through the NMDA receptors in a neurons of basal ganglia. Conclusions: It is concluded that manganese neurotoxicity in basal ganglia was partially mediated by nitric oxide in the cell culture model.
결장경 시행 중 발견된 장 게실염에 의한 방광-S결장루
정용욱 ( Yong Wook Jung ),유정현 ( Jung Hyun Yoo ),이정수 ( Jung Soo Lee ),장병익 ( Byung Ik Jang ),김경옥 ( Kyeong Ok Kim ),정상훈 ( Sang Hun Jung ) 대한소화기학회 2011 대한소화기학회지 Vol.58 No.5
Enterovesical fistular is an abnormal communication between the intestine and the bladder. It represents a rare complication of intestinal diverticulitis, colorectal malignancy, bladder cancer, inflammatory bowel disease, radiotherapy, and trauma. The most common etiology is diverticular disease. A 70-year-old man came to our hospital due to frequent urinary tract infection, dysuria, pneumaturia and fecaluria. Sigmoidoscopy revealed a large diverticulum with impacted stool at the sigmoid colon. When the scope was inserted into the site, the patient complained of severe urgency and pneumaturia. CT scan was performed. 1.5 cm sized fistular tract between the sigmoid colon and bladder was noted. According to the endoscopy and CT finding, the diagnosis of colovesical fistula was made. The patient underwent surgical intervention. At laparotomy, there were multiple diverticula and fistular tract was noted. (Korean J Gastroenterol 2011;58:284-287)