http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
초음파 주파수 및 반응조건 변화에 따른 나프탈렌 분해효율과 OH 라디칼의 발생량 비교
박종성(Jong Sung Park),박소영(So Young Park),오재일(Jei Ll Oh),정상조(Sang Jo Jeong),이민주(Min Ju Lee),허남국(Nam Guk Her) 大韓環境工學會 2009 대한환경공학회지 Vol.31 No.2
나프탈렌은 휘발성이 있는 소수성 물질로 발암유발 가능성이 있고, 수생태계에 심각한 영향을 미친다. 본 연구는 초음파의 주파수 및 반응조건별 나프탈렌 분해효율과 OH 라디칼 변화량을 조사하였다. C-18 역상칼럼을 이용한 LC/FLD (1200 series, Agilent)로 나프탈렌을 분석한 결과 MDL (Method detection limit)은 0.01 ppm이었다. 초음파 조사 동안 휘발된 나프탈렌은 거의 검출되지 않았고(0.05 ppm 이하), 반응조 덮개 개폐별 나프탈렌 분해효율은 거의 차이를 보이지 않았다(1% 이내). 초음파 반응온도가 증가할수록 나프탈렌 제거효율은 감소하는 경향(15℃: 95%→40℃: 85%)을 보였고, pH가 낮을수록 나프탈렌 분해효율이 증가(pH 12: 84%→pH 3: 95.6%)하였다. 나프탈렌 초기농도의 감소에 따라 반응속도는 증가하는 경향을 보여주었다(2.5 ppm: 27.3×10(-3) min(-1), 5 ppm: 22.7×10(-3) min(-1), 10 ppm: 19.0×10(-3) min(-1)). 동일한 초음파 조건(2.5 ppm 나프탈렌, 0.075 W/mL, 20℃, pH 6.8)에서 28 kHz의 분해효율이 132 kHz보다 약 1.46배 높았고(132 kHz: 56%, 28 kHz: 82.7%), 유사 일차반응 속도상수(k1)도 약 2.3배 높게 나타났다(132 kHz: 2.4×10(-3) min(-1), 28 kHz: 5.0×10(-3) min(-1)). 초음파 조사 10분 후 H₂O₂ 농도는 132 kHz가 28 kHz보다 약 7.2배 높았지만(132 kHz: 0.36 ppm, 28 kHz: 0.05 ppm), 조사 90분 후에는 28 kHz가 132 kHz보다 1.1배 높았다(28 kHz: 0.45 ppm, 132 kHz: 0.4 ppm). 2.5 ppm 나프탈렌 용액에 132 kHz와 28 kHz 초음파 조사시 발생된 H₂O₂ 농도는 초순수에 초음파 조사한 결과보다 각각 0.1 ppm과 0.05 ppm씩 낮게 나타났다. 혼형(24 kHz)과 배스형(28 kHz) 초음파의 나프탈렌 분해효율은 각각 87%와 82.7%였고, k1은 22.8×10(-3) min(-1)와 18.7×10(-3) min(-1)로 산출되었다. 다주파 복합형 초음파 시스템(28 kHz 배스형+24 kHz 혼형 초음파)의 나프탈렌 분해효율은 단일주파수 24 kHz(혼형)와 비슷한 제거효율을 보였으나(88%), H₂O₂의 농도는 약 3.5배 높게 조사되었다(28 kHz+24 kHz: 2.37 ppm, 24 kHz: 0.7 ppm). 이와 같은 다주파 복합형 초음파 시스템은 OH 라디칼에 의해 산화가 잘 일어나는 물질의 분해에 매우 효과적으로 적용될 수 있을 것으로 예상된다. Naphthalene is a volatile, hydrophobic, and possibly carcinogenic compound that is known to have a severe detrimental effect to aquatic ecosystem. Our research examined the effects of various operating conditions (temperature, pH, initial concentration, and frequency and type of ultrasound) on the sonochemical degradation of naphthalene and OH radical production. The MDL (Method detection limit) determined by LC/FLD (1200 series, Agilient) using C-18 reversed column is measured up to 0.01 ppm. Naphthalene vapor produced from ultrasound irradiation was detected under 0.05 ppm. Comparison of naphthalene sonodegradion efficiency tested under open and closed reactor cover fell within less than 1% of difference. Increasing the reaction temperature from 15℃ to 40℃ resulted in reduction of naphthalene degradation efficiency (15℃: 95%→40℃: 85%), and altering pH from 12 to 3 increased the effect (pH 12: 84%→pH 3: 95.6%). Pseudo first-order constants (k1) of sonodegradation of naphthalene decreased as initial concentration of naphthalene increased (2.5 ppm: 27.3×10(-3) min(-3)→10 ppm : 19.0×10(-3) min(-3)). Degradation efficiency of 2.5 ppm of naphthalene subjected to 28 kHz of ultrasonic irradiation was found to be 1.46 times as much as when exposed under 132 kHz (132 kHz: 56%, 28 kHz: 82.7%). Additionally, its k1 constant was increased by 2.3 times (132 kHz: 2.4×10(-3) min(-1), 28 kHz: 5.0×10(-3) min(-1)). H₂O₂ concentration measured 10 minutes after the exposure to 132 kHz of ultrasound, when compared with the measurement under frequency of 28 kHz, was 7.2 times as much. The concentration measured after 90 minutes, however, showed the difference of only 10%. (concentration of H₂O₂ under 28 kHz being 1.1 times greater than that under 132 kHz.) The H₂O₂ concentration resulting from 2.5 ppm naphthalene after 90 minutes of sonication at 24 kHz and 132 kHz were lower by 0.05 and 0.1 ppm, respectively, than the concentration measured from the irradiated M.Q. water (no naphthalene added.) Degradation efficiency of horn type (24 kHz) and bath type (28 kHz) ultrasound was found to be 87% and 82.7%, respectively, and k1 was calculated into 22.8×10(-3) min(-1) and 18.7×10(-3) min(-1), respectively. Using the multi- frequency and mixed type of ultrasound system (28 kHz bath type+24 kHz horn type) simultaneously resulted in combined efficiency of 88.1%, while H₂O₂ concentration increased 3.5 times (28 kHz+24 kHz: 2.37 ppm, 24 kHz: 0.7 ppm.) Therefore, the multi-frequency and mixed type of ultrasound system procedure might be most effectively used for removing the substances that are easily oxidized by the OH radical.
Sung Kyu Hong,Won Ki Lee,Woong Na,Jung Soo Nam,Jong Jin Oh,Chang Wook Jeong,Seok-Soo Byun,Sang Eun Lee 대한비뇨기종양학회 2010 대한비뇨기종양학회지 Vol.8 No.3
Purpose: We tried to identify potential preoperative predictors of benign histology among small (≤4cm) renal masses presumed to be malignant by analyzing a contemporary cohort of patients who received surgical management for such renal lesions. Materials and Methods: We reviewed records of 202 patients who received radical or partial nephrectomy for small (≤4cm) enhancing renal mass deemed suspicious for malignancy between 2004 and 2009. Both uniand multivariate logistic regression models were applied to examine the potential association of various preoperative variables with benign histology of small renal mass. A receiver operator characteristics (ROC) curve was applied to assess accuracies of potential predictors. Results: Of the 207 small renal masses resected from 202 patients, 20 (9.7%) were found to be pathologically benign lesion. Among various preoperative factors, only female gender (p=0.041) and smaller tumor size measured on preoperative computed tomography scan (p=0.049) were observed to be independent predictors of benign histology in multivariate analysis. Areas under ROC curves for gender, tumor size, and predictive model combining the two variables were 0.611, 0.615, and 0.681, respectively, demonstrating no significant differences among the three curves (all p>0.05). Conclusions: Although gender and tumor size were identified to be independent predictors of benign histology for small renal masses deemed suspicious for malignancy, the levels of accuracies for the two predictors were observed to be less than satisfactory. Further efforts should be made to improve the diagnostic approaches for small renal mass suspicious for malignancy.
Novel Impulsive Driving Schemes for 120Hz LCD Panels
Nam, Hyoung-Sik,Oh, Jae-Ho,Shin, Byung-Hyuk,Oh, Kwan-Young,Berkeley, Brian H.,Kim, Nam-Deog,Kim, Sang-Soo The Korean Infomation Display Society 2008 Journal of information display Vol.9 No.1
Two new impulsive driving technologies for 120Hz liquid crystal display (LCD) panels are proposed to improve moving picture quality. One technology generates the dark frame using an adder and a shifter simply without using any look up tables (LUTs). It results in a cost effective impulsive scheme with motion picture quality comparable to that of high speed driving. The other is a backlight flashing method designed to avoid ghost images. The issue of ghost images caused by the slow response time of liquid crystal (LC) is solved by means of 120Hz overdriving and 120Hz backlight flashing. Using the perceived blur edge time (PBET) metric, measured moving picture response time (MPRT) values were 10.8ms and 4.4ms, respectively, while that of 120Hz high speed driving was 10.1ms.
Nam, Kyung-Yeub,Chang, Ki-Ho,Kim, Kyung-Eak,Oh, Sung-Nam,Choi, Young-Jean,Kim, Kyung-Sik,Lee, Dong-In,Kim, Kum-Lan The Korean Society of Remote Sensing 2008 大韓遠隔探査學會誌 Vol.24 No.1
Rainfall data from three different types of rain gauge system have been collected for the summertime rain event at Mokpo in the Korean peninsula. The rain gauge system considered in this paper is composed of three tipping-bucket rain gauges with 0.1, 0.2, and 0.5 mm measuring resolutions, the Optical Rain Gauge (ORG), and the PARSIVEL (PARticle SIze and VELocity). The PARSIVEL rainfall rate has been considered as the reference for comparison since it gave good resolution and performance on this event. Comparison with the PARSIVEL rainfall rate gives the results that the error and temporal variation of rainfall rate are simultaneously reduced with increasing the averaging interval of rainfall rate or decreasing the size of tipping bucket. This suggests that the estimated rainfall rate must be optimized, differently for the type of tipping-bucket rain gages, by minimizing the averaging interval of rainfall rate under the condition satisfying the given performance of rainfall rate.
Sung-Min Rhee,Gun Woo Nam,Joo Hyun Park,Hyeon Jang Jeong,Suk-Hee Park,Joo Han Oh 대한견주관절의학회 2021 대한견주관절학회 학술대회논문집 Vol.2021 No.3
Introduction and Background To compare the efficacy between the direct effect of nanofiber-based vitamin D sheet engineered with 3D printing(VTD sheet) and vitamin D supplementation(VTDS) as diet on tendon-to-bone healing and muscle regeneration after repair in a chronic rotator cuff tear model of rabbit Material and Method Sixty-four rabbits were randomly allocated into two groups(n=32), then each group was allocated into four small groups (Group A,A’:VTDS only,Group B,B’:Normal diet+sheet without vitamin D,Group C,C’:Normal diet+VTD sheet,Group D,D’:VTDS+VTD sheet,n=8 each). The supraspinatus tendons were repaired with the sheet only for groups B and B’, and VTD sheet for groups C,C’,D and D’ (Figure 1). Groups A,B,C, and D and groups A’,B’,C’, and D’ were extracted at 4 and 12 weeks after repair. respectively. Serum 25-OH VTD level was checked. The genes including COL1, COL3, BMP-2, SCX, SOX9, and ACAN was assessed at 4 and 12 weeks after repair. The histological and biomechanical evaluations of tendon-to-bone healing were done at 12 weeks after repair. Rotator cuff muscle cross-sectional areas were measured at 4 and 12 weeks after repair. ELISA was done to calculate vitamin D level in muscle at 12 weeks after repair. Results Serum VTD level of group D and D’ was highest among groups at the time of repair and extraction(p<0.001). At 4 weeks after repair, mRNA expression of COL1 in group D was highest among groups(p=0.046). At 12 weeks after repair, group D’ showed most dense collagen density(p=0.037), and had highest load to failure among groups(p=0.024). Regarding muscle regeneration, the cross-sectional area of muscle fiber was largest in group D and D’ at 4 and 12 weeks after repair(p<0.05) with highest VTD level of muscle by ELISA at 12 weeks after repair(p=0.003). Conclusions The use of nanofiber-based VTD sheet engineered with 3D printing may promote tendon-to-bone healing and regenerate rotator cuff muscle after repair in a chronic rabbit rotator cuff tear model.