• 한국건축시공학회지
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• 제16권1호
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• pp.1-7
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• 2016

본 연구에서는 $-5^{\circ}C$이하에서도 가열 양생이 없이 수화 반응시 수화열이 높게 발생되는 환원슬래그를 시멘트 분체와 치환사용 하여 영하의 온도에서도 콘크리트의 자체 발열로 인해 압축강도를 재령 3일 이내 5MPa를 발현시켜 초기동해를 방지시키는 것이 최종 연구의 목적이며 이에 대하여 환원슬래그의 물리적 특성 평가와 열적 특성 평가를 실시한 결과 환원슬래그는 높은 수화열을 발생시키기 때문에 저온에서도 압축강도 발현이 우수함을 알 수 있었다. 이는 환원 슬래그의 성분 중 $C_{12}A_7$과 $C_3A$에 의해 수화열이 높게 발생됨 저온에서도 압축강도가 발현되는 것으로 나타났다. 하지만 환원슬래그 단독 치환하였을 경우 $SO_3$함량 부족으로 급결이 발생하는 것을 알 수 있었다. 급결을 방지하기 위해서는 석고의 사용이 필수적으로 사용되어야 한다. 따라서 본 연구 결과 환원슬래그와 석고를 3성분계로 사용하였을 경우 저온에서도 재령 3일에서 5MPa 압축강도를 나타나는 것으로 보아 저온에서도 콘크리트의 초기동해를 방지할 수 있을 것으로 판단된다.

• Steel and Composite Structures
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• 제21권1호
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• pp.195-216
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• 2016

The dynamic characteristics of continuous steel-concrete composite beams considering the effect of interlayer slip were investigated based on Euler Bernoulli's beam theory. A simplified calculation model was presented, in which the Mode Stiffness Matrix (MSM) was developed. The natural frequencies and modes of partial-interaction composite continuous beams can be calculated accurately and easily by the use of MSM. Proceeding from the present method, the natural frequencies of two-span steel-concrete composite continuous beams with different span-ratios (0.53, 0.73, 0.85, 1) and different shear connection stiffnesses on the interface are calculated. The influence pattern of interfacial stiffness on bending vibration frequency was found. With the decrease of shear connection stiffness on the interface, the flexural vibration frequencies decrease obviously. And the influence on low order modes is more obvious while the reduction degree of high order is more sizeable. The real natural frequencies of partial-interaction continuous beams commonly used could have a 20% to 40% reduction compared with the fully-interaction ones. Furthermore, the reduction-ratios of natural frequencies for different span-ratios two-span composite beams with uniform shear connection stiffnesses are totally the same. The span-ratio mainly impacts on the mode shape. Four kinds of shear connection stiffnesses of steel-concrete composite continuous beams are calculated and compared with the experimental data and the FEM results. The calculated results using the proposed method agree well with the experimental and FEM ones on the low order modes which mainly determine the vibration properties.

• 한국융합학회논문지
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• 제8권1호
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• pp.43-49
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• 2017

심장CT를 스캔하여 MAR알고리즘 적용 시 자체 제작한 Pacemaker삽입팬텀의 금속인공물 감소 정도를 비교 분석해 보았다. 에너지별 CT value를 비교한 결과 BKI에서 CT value의 증감이 있었으며 WSA에서 40 KeV의 경우 663.2%로 최대감소, BHA에서 140 KeV의 경우 56.2%로 최대로 증가 하였다. 또한, 70 KeV기준으로 인공물 형태별 CT value 비교결과 WSA에서 최대 약 145% 감소하였고, BHA에서는 최대 약 46.38%증가 하였다. MAR알고리즘 적용 은 에너지 변화 또는 인공물의 종류와 무관하게 금속 인공물 발생을 감소시켜주는 효과가 있어 Pacemaker삽입 후 심장CT로 추적검사 시 MAR알고리즘을 적용한다면 보다 질 좋은 심장CT 영상을 제공할 것으로 사료된다.

• Journal of the Korean Wood Science and Technology
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• 제46권2호
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• pp.202-210
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• 2018

This study was carried out to quantify degree of contribution of harvested wood product (HWP) on mitigation of climate change by valuation of public benefits, environmentally and economically. The potential carbon dioxide emission reduction of HWP was estimated by accounting carbon storage effect and substitution effect. Based on 2014 statistics of Korea Forest Service, domestic HWPs were sorted by two categories, such as wood products produced domestically from domestic and imported roundwood. The wood products were divided into seven items; sawnwood, plywood, particle board, fiberboard (MDF), paper (including pulp), biomass (wood pellet) and other products. The carbon stock of wood products and substitution effects during manufacturing process was evaluated by items. Based on the relevant carbon emission factor and life cycle analysis, the amount of carbon dioxide emission per unit volume on HWP was quantified. The amounts of carbon stock of HWP produced from domestic and from imported roundwood were 3.8 million $tCO_{2eq}$., and 2.6 million $tCO_{2eq}$., respectively. Also, each reduction of carbon emission by substitution effect of HWP produced from domestic and imported roundwood was 3.1 million $tCO_{2eq}$. and 2.1 million $tCO_{2eq}$., respectively. The results of this study, the amount of carbon emission reduction of HWP, can be effectively used as a basic data for promotion of wood utilization to revise and establish new wood utilization promotion policy such as 'forest carbon offset scheme', and 'carbon storage labeling system of HWP'.

• 대한두개안면성형외과학회지
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• 제16권3호
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• pp.114-118
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• 2015

Background: The reduction of orbital blowout fracture primarily aims to normalize the extra-ocular movement by returning the herniated orbital soft tissue into the original position, and to prevent enophthalmos by normalizing the orbital cavity volume. We introduce a balloon catheter-assisted orbital floor reduction technique. Methods: A retrospective review was performed for all patients with orbital floor fracture who underwent the technique described in the main body of this text. Medical records were reviewed for demographic data, clinical presentation and course, degree of enophthalmos, intraorbital volume on computed tomography scan, and postoperative outcomes. The enophthalmos and intraorbital volume of the injured site were compared to the uninjured eye and orbit. Results: The review identified 14 patients (11 male, 3 female). The mean preoperative difference in en-exopthalmos was 2.13 mm, while the mean orbital volume was 116%. The mean postoperative difference in en-exophthalmos had improved to 0.61 mm with a mean orbital volume of 101.85%. At the time of catheter removal at 10 days, three patients experienced diplopia (n=1), extra-ocular movement disorder (1), or enophthalmos (1). All of these had resolved by the 6-month follow-up visit. Conclusion: Balloon catheter-assisted reduction of the orbital floor fractures was associated with improvements in intraorbital volume and enopthalmos in the 14 patients. Notable complications included diplopia, enophthalmos, and limited extra-ocular movement, all of which were transient in the early postoperative period and had resolved by 6-month follow up.

• 대한족부족관절학회지
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• 제8권1호
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• pp.71-75
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• 2004

Purpose: The purpose of this study was to evaluate retrospectively the clinical results of closed reduction and percutaneous screw fixation for unstable injuries on stress radiographs in subtle injuries of Lisfranc joint. Materials and Methods: From June 1997 to March 2003, 6 cases of unstable injuries on stress radiograph in subtle injuries of Lisfranc joint were treated by percutaneous cannulated screw fixation after closed reduction. All cases were injuried by indirect force (twisting injury). The average diastasis between the 1st and 2nd metatarsal base was 3 mm (2-4 mm) on initial nonweight bearing AP radiograph. The average follow-up period was 20 months. Clinical evaluation was assessed according to the American Orthopedic Foot and Ankle Society (AOFAS) midfoot score. Results: The AOFAS midfoot score was average 86 (80-90) points. The average diastasis between 1st and 2nd metatarsal base was 2 mm (1-3 mm) on weight bearing AP radiograph in final follow up. The final diastasis was increased slightly than diastasis in initial postoperative radiographs. But the clinical results were good. There was no correlation between the degree of diastasis and the clinical results. On weight bearing lateral radiograph, the average difference with normal foot in the distance between plantar aspect of 5th metatarsus and medial cuneiform was 2 mm (0-3 mm). One case had mild arthritic change on the radiographs. Conclusion: When the Lisfranc injuries, especially in the subtle injuries were suspicious, the stress views are helpful to assess stability of the Lisfranc injuries and planning of treatment. For unstable injuries on stress radiographs in subtle injuries of Lisfranc joint, closed reduction and percutaneous screw fixation is useful method to expect good clinical results.

• 한국실내디자인학회논문집
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• 제27권3호
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• pp.136-144
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• 2018

The purpose of this study is to examined the unconscious response of the pupil in the observation toward the image in the eye-tracking experiments that target on a large complex cultural space. Twenty-five men participated in this experiment and the observation data were analyzed in seconds per minute on watching time. It could examine the unconscious response of information searching in the change of pupil size in the process of observing the space. The results could be defined as following several points. First, it was possible to outline the unconscious response characteristics of pupil by analyzing sudden changes in pupil size as total, cumulative, and individual. The response characteristics using frequency and time can be utilized as the analytical method to examine the degree of interest of spatial components according to the purpose of analysis in the future. Second, according to the over ${\pm}5%$ of cumulative variation rate on the pupil size change, during in the 60 seconds, the continuous pupil dilation was used 25.2 seconds in 8.8 rounds and the pupil reduction was used 18.0 seconds in 7.0 rounds. Third, when the variation rate of ${\pm}5%$ or more was regarded as the sudden changes on pupil size by individual variation, the pupil dilation was 7.2 rounds of 8.6 seconds and pupil reduction was 6.0 seconds in 5.0 rounds. This means that the pupil increases 9.3% in one expansion and decreases -8.5% in the reduction process. As regarding pupil changes as cumulative rate, it appeared high change rate on pupil reduction but it became higher on pupil dilation in individual.

• 유기물자원화
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• 제13권2호
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• pp.91-97
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• 2005

본 연구는 종이 다른 여러 가지 미생물을 사용하여 음식물쓰레기 침출수의 악취저감 효과를 가지는 균주를 선별하고자 실시하였다. 침출수에 전배양한 해수미세조류인 Spirulina plantensis 와 Chlorella vulgaris, 효모 Saccharomyces cerevisae와 세균인 Bacillus cereus를 각각 10% 주입하여 총 10일간 배양하였다. 72시간 주기로 pH와 염도, 관능검사를 시행한 결과, pH는 초기에 3.5~4.0 값을 보였으나 시일이 경과함에 따라 4.9~7.4 수준까지 증가하였고, 염도는 Chlorella vulgaris와 Spirulina platensis는 급격히 낮아졌다. 관능평가를 통한 악취시험 결과 광합성 미세조류인 Chlorella vulgaris가 발효 종료일인 10일째 거의 취기를 느낄 수 없는 악취도 1을 나타내어 악취제어에 효과가 있는 것으로 나타났다.

• Carbon letters
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• 제8권4호
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• pp.280-284
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• 2007

Samples of active carbon of $1150\;m^2/g$ surface area were impregnated with ammoniacal salts of copper, chromium and silver, with and without triethylenediamine. The samples of impregnated carbon were aged at $50^{\circ}C$, with and without 90% RH (relative humidity), for a little more than one year and chemically evaluated periodically. Initially copper (II) and chromium (VI) reduced very fast in the samples in humid atmosphere to the extent of 30% and 60% respectively in four months. These values were found to be unaffected by the presence of triethylenediamine (TEDA) indicating that the chemical did not retard the reduction process of chromium (VI) and copper (II). However, in the absence of humidity the reduction of the impregnants was significantly less (10-12%, w/w) in four months. It was quite evident; therefore, that the moisture was mainly responsible for the reduction of chromium (VI) and copper (II) species in impregnated carbons. The prolonged ageing of the samples with and without triethylenediamme after four months with and without humid atmosphere showed that the extent of reduction of chromium (VI) was very low, i.e. 5-10% and of copper (II) was 2-25%. Silver is not reduced due to carbon, as it remained unchanged in concentration on storage. The impregnated carbon samples (100 g) without triethylenediamine, which were aged at room temperature for 5 years in absence of humidity and unaged when evaluated against cyanogen chloride (CNCl) at a concentration of 4 mg/L and airflow rate of 30 lpm showed a high degree of protection (80- 110 minutes).

• 한국식품조리과학회지
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• 제31권6호
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• pp.756-763
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• 2015

As food waste problems become more severe, the need for reduction plans is increasing. Thus, this study aimed to discover the attitudes towards and the intentions to reduce restaurant food waste as well as the importance of and intentions to participate in reduction plans among adults customers A self-administrated questionnaire was given to 361 adults (216 men and 145 women) over 20 years old residing in Seoul and Gyeonggi province. According to the results, the respondents regarded restaurant food waste problems as serious (4.01). The biggest reason for leaving food was concern about hygiene (3.57), followed by tasting food (3.34) and portions that were too large (3.10). 57.6% responded that they try to reduce food waste when dining out. Women over 30 admitted to leaving food when dining out if the food did not taste as expected, if they had health concerns about additives such as condiments, and for body weight management. The overall average degree of awareness on the gravity of restaurant food waste problems was 4.06, indicating that respondents deeply empathized with the matter. Women showed higher alertness compared to men, and respondents in their 30s or over did more than those in their 20s. Also, respondents who try to reduce food waste when dining out had higher levels of concern than those who did not. According to the results from measuring the importance of and intention to participate in restaurant food waste reduction plans, taking away left-over food was the best option. In short, citizenship improvement campaigns should be designed for restaurants and related organizations in order to stimulate the need and effects of efforts to reduce dine-out food waste and induce aggressive participation by consumers. Diverse methods to increase actual consumer participation in food waste reduction plans that show high consumer participation intentions also needs to be developed.