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도로공사 우수배제시설의 시공성 및 성능 개선에 관한 연구
강인석,박서영,곽중민,이우식,정수언 경상대학교 생산기술연구소 2001 工學硏究院論文集 Vol.1 No.-
Generally, a street-inlet in road facility is aimed to exclude rainfall and filth from sewer system. In order to solve some problems in current street inlet facilities, some revised inlet systems have been suggested. Those revised facilities can also solve an environmental problem like a bad smell emitting from the worn facility and solve civil petitions due to its safety and poor quality of passing rainfall. In this study, the existing rainfall exclusion facility was investigated including foreign countries and a developed street inlet model was represented through estimating of their structures, characteristics and costs. It also be analyzed that the existing problems can be solved by a trial construction and the developed model was compared with existing models by focusing on constructability and maintenance capacity.
Pd 촉매 하에서 terminal alkynes, aryl, alkenyl 혹은 alkynyl iodine 화합물의 수용성 조건에서 cross-coupling에 관한 연구
강석구,이홍우,장수범,호필수 성균관대학교 기초과학연구소 1995 論文集 Vol.46 No.2
The ligand-free Pd(OAc)_2-catalyzed coupling reaction of aryl-, alkenyl-, and alkynyliodonium tetrafluoroborate and iodanes with terminal alkynes proceeds readily in the presence of NaHCO_3 in aqueous medium to afford the substituted alkynes in high yields under mild conditions.
Pd 촉매하에서 allylic alcohol과 hypervalent iodine 화합물의 위치 선택적 vinylation에 관한 연구
강석구,이홍우,장수범,김태현,편성재 성균관대학교 기초과학연구소 1995 論文集 Vol.46 No.2
The formation of carbon-carbon bond by palladium-catalyzed coupling of aryl or vinyl halides with olefins, known as the Heck reaction, has become a powerful tool in organic chemistry. In the case of allylic alcohols, palladium-catalyzed reaction of organic halides usually affords β-substituted ketones or aldehydes rether than β-substituted allylic alcohols.
표면근전도와 전자각도기를 이용한 자동차 부품 조립작업 위험요인 평가
강동묵,이철호,,신용철,김은아,우지훈,조병만,이수일 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4
Objectives: As automobile part manufacturing is characterized by high speed and high repetition, observation methods which are usually utilized for static posture are inappropriate to evaluate musculoskeleatal risk factors. This study quantified the risk factors of musculoskeletal disorders on the forearm and suggested exposure limits by estimating the risk factors using surface electromyography (EMG) and electrogoniometer. Methods: Ten percent of the total workers at 3 automobile part manufacturing factories were randomly selected, and 99 male workers were recruited as study subjects. The study was conducted during May 2003 to September 2004. The workers were equipped with electrogoniometers on the wrist and the elbow, surface EMGs on the skin of the flexor digitorum superficialis (FDS) and extensor carpi radialis (ECR) muscles, and the heart beat recorder during work as indicators of joint movement, local muscle tension and physical work load, respectively. Results: After controlling for age, body mass index and job stress, wrist flexion maximum angle, FDS relative activity (RA) and ECR RA were significantly associated with forearm musculoskeletal symptoms. The odds ratios of the forearm were 5.0(95% CI: 1.1-22.7), 14.0(95% CI: 1.5-128.8) and 7.3(95% CI: 1.1-49.4) for wrist flexion maximum angle more than 76˚, FDS RA more than 2.8%, and ECR RA more than 3.5%, respectively. Conclusions: Joint angle and focal muscle activity were associated with forearm musculoskeletal symptoms. To reduce forearm musculoskeletal symptoms among automobile part manufacturers, the wrist flexion angle, and FDS and ECR activity need to be reduced below the guidelines recommended in this study.
플라이애시를 다량 치환한 콘크리트의 탄산화 특성에 관한 실험적 연구
김우상,강태경,백민수,김성식,정상진 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)
This study evaluated durability through measurement of substituted test piece's pH degree and experiments of carbonation. Comparing and evaluating cared test piece's pH degrees which we got before the carbonation and after the carbonation. After evaluating carbonation depth through carbonation, evaluating carbonation properties by fly-ash replacement ratio pH degree was decreased by cement replacement ratio of fly-ash. And in the case of substitution of the same amount of fly-ash. Fine aggregate replacement ratio was increased. When the test piece. Which had been cared in high temperature, was promoted to carbonation. Among the test piece which was replaced with fly-ash 40%, the test piece which has high rate of fine aggregate proved opposition of carbonation. Through the test, I summarized that the test piece cared in high temperature was mostly effected by compress strength the test piece cared in low temperature was mostly effected by pH degree.
응집공정에 적합한 In-Line 정적혼화기를 이용한 혼화공정의 개선
정철우,강민수,최시환,정수일,손인식,강임석 대한상하수도학회 2003 상하수도학회지 Vol.17 No.3
The rapid mixing process for coagulation is a critical component in a water treatment plant. However, at the present time a detailed understanding of the rapid mixing by in-line mixer or generally accepted criteria for the design of in-line static mixer are not available. The aim of this work is therefore to improve the understanding of how the in-line static mixer works and how to better utilize it in coagulation process in water treatment. To investigate the performance of static mixer, coagulation experiments were conducted to compare the static mixer to the traditional backmixer under several coagulation conditions. Experiments were also performed to compare the coagulation efficiency of different mixing type of static mixer which were made using different flow rates and the number of elements equipped in a pipe. The static mixer performed better than the backmixer for all coagulation and mixing conditions tested. Especially, the static mixer was very effective in the surface charge neutralization, as showing higher reduction of negative charge with increasing mixing intensity. However, little difference was observed in the performance of the static mixer equipped with 2, 3, and 5 elements. Also, in a series of bench-scale studies of rapid mixing, the in-line static mixer performed better than the traditional backmixer for both adsorption and charge neutralization (A/N) mechanism and sweep coagulation mechanisms. Especially, the static mixer was more efficient at producing A/N mechanism conditions as a result of its fast and uniform dispersion of the coagulant.
유니버셜모터의 저차 고조파전류 저감을 위한 속도제어기에 관한 연구
임홍우,박수강,백형래 조선대학교 에너지.자원신기술연구소 2000 에너지·자원신기술연구소 논문지 Vol.22 No.1
Universal motors are commonly used for portable tools and other application. The universal motors can be implied AC or DC voltage source. Phase-angle control AC drive systems gain a high popularity due to their simple implementation despite the disadvantage of their poor input power factor especially for large values of phase delay angle. Futhermore it contains a large amount of subharmonic current. But pulse width modulation controlled DC drive systems reduce these problems. This paper compared the harmonic characteristics of phase angle control AC system that is controlled by TCA785 with zero voltage crossing similar to traditional system and DC chopper system that is used in PWM controller.