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문학룡,배정렬,한천구 청주대학교 산업과학연구소 2003 産業科學硏究 Vol.21 No.1
This study discusses the influence of fineness of cement on the properties of cement mortar. According to the results, compressive strength shows a higher value in order of high early cement with 8000㎠/g of fineness(C), 4600㎠/g of fineness(B), 3000㎠/g of fineness(A) and ordinary cement(OPC) at mixture proportion of 1:3, and it does in order of C, B, OPC and A at mixture proportion of 1:1. Compressive strength shows a higher value in order of exposure at outside, standard and air curing with variation of curing condition. Flexural strength shows the similar tendency with compressive strength, and is about 1/7∼1/6 in comparison with compressive strength. And, its correlativity is above 0.93, so it is very favorable. Length change by drying shrinkage is higher in order of C, B, OPC and A at mixture proportion of 1:1 and 1:3.
문학룡,한대철,강원평 한국도로학회 2013 한국도로학회논문집 Vol.15 No.4
PURPOSES: The purpose of this study is to research the influence of road traffic noise by road slope through the analysis of the field road traffic noise and determine consideration of road slope in the case of appling active noise cancellation. METHODS: This study measures vehicle’s noise by the NCPX method at the three field sections such as uphill, downhill, and flatland. Total sound pressure and sound pressure level by the 1/3 octave band frequency are calculated through the raw field data. Total sound pressure level is compared by ANOVA test and T test statistically. The results obtained are compared in accordance with the road slope and the progress of the uphill section. RESULTS : The noise characteristic of early, medium, and last parts of uphill was found to be consistent when the vehicle was travelling uphill section. The result of statistical test, it was shown that total sound pressures are not different each other. According to the comparison by the geometry, sound pressure of the uphill section was higher than those of the flatland and downhill section in high frequency band. By the result of statistical test, total sound pressure are different according to geometry in the case of high vehicle speed. In the comparison result by road slope, each sound pressure level was found to be consistent in total frequency. However, total sound pressure proportionally increased according to road slope. CONCLUSIONS: It is found that the effect of road slope on noise generation was little in this experimental sites.
도로 소음 저감을 위한 능동소음제어 시스템의 개발 및 기초실험
문학룡,강원평,임유진 한국도로학회 2013 한국도로학회논문집 Vol.15 No.6
PURPOSES: The purpose of this study is about noise which is generated from roads and is consist of irregular frequency variation from low frequency to various band. The existing methods of noise reduction are sound barrier that uses insulation material and absorbing material or have applied passive technology of noise reduction by devices. The total frequency band is needed to apply active noise control. METHODS: In this study applies to the field of road traffic environment, signal processing controller and various analog signal input/output, the amplifier module is based on parallel-core embedded processor designed. DSP performs the control algorithm of the road traffic noise. Noise sources in the open space performance of evaluation were applied. In this study, controller of active signal processor was designed based on the module of audio input/output and main controller of embedded process. The controller of active signal processor operates noise reduction algorithm and performance tests of noise reduction in inside and outside environment were executed. RESULTS : The signal processing controller with OMAP-L137 parallel-core processors as the center, DSP processors in the active control operations dealt with quickly. To maximize the operation speed of an object and ARM processor is external function keys and display for functions and evaluating the performance management system was designed for the purpose of the interface. Therefore the reduction of road traffic noise has established an electronic controller-based noise reduction. CONCLUSIONS : It is shown that noise reduction is effective in the case of pour tonal sound and complex tonal sound below 500Hz by appling to Fx-LMS.
회수수에 처리되는 당류계 안정화제의 혼입률 변화가 콘크리트의 품질에 미치는 영향
文學龍,金虎林,우종완,한민철,한천구 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)
The objective of present paper is to investigate the engineering properties of concrete using recycling water incorporating saccharic based stabilizing agent in order to improve qualities of concrete in the region of normal strength and high strength. According to test results, fluidity and air content do not exhibit significant difference with an increase in stabilizing agent contents. Bleeding was not observed at 30% of W Ie, regardless of stabilizing agent contents, nonetheless, concrete with stabilizing agent of 0.15% was observed to occur the least bleeding at 40 and 50% of W IC. For setting time, although presence of recycled water accelerates setting time, setting time shows to be retarded gradually with an increase in stabilizing agent content. For compressive strength, use of stabilizing agent enhanced compressive strength of concrete compared with that of concrete without stabilizing agent. In the side of strength enhancement, adequate dosage of stabilizing agent is found to be 0.15%. As dosage of stabilizing agent increased above 0.15%, drying shrinkage exhibited a tendency to decrease.