DAF에서 압력에 따른 미세기포의 크기특성

한무영,박용효,이준,심재수 대한상하수도학회 2002 상하수도학회지 Vol.16 No.2

Although DAF (Dissolved Air Rotation) has been successfully accepted for water and wastewater treatment, the fundamental characteristics of the process have not been fully investigated. According to recent theoretical work on DAF, bubble size is one of the most important factors that affect the DAF efficiency. It is well known that the size of bubbles in DAF is mostly affected by applied pressure. In this study, a newly developed Particle Counter Method (PCM) is introduced and compared with image analysis and verified. Using this PCM, the size of bubbles in DAF is measured under various pressure conditions from 2-6atm. Through a set of experiments, it was found that bubble size decreases as the pressure increases up to 3.5atm. This is a critical pressure after which bubble size does not decrease. According to the experimental results, it is not only costly but also unnecessary to maintain pressure more than 3.5atm if the goal is only to generate smaller bubbles for better removal efficiency in DAF operational practice.

재활용 폐페인트를 이용한 방청페인트 개발연구

한대상,정재헌,조홍식,조창제,이종무,장상목 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.2

In this study, The method to produce anticorrosive paint using reproductive wastepaint was investigated. The liquid-phase resin, BHO-500 and powder-phase paint BHO-300 were produced through wastepaint reproductive process. BHO-500 and BHO-300 could be replaced respectively polyvinylchloride resin and filler, which are thr components of anticorrosive paint. The properties of the anticorrosive paint produced through this process were excellent in comparison with the existing anticorrosive paint.

레이저 클래딩 중첩도가 표면특성에 미치는 영향

이제훈, 서무홍, 한유희 한국레이저가공학회 2000 한국레이저가공학회지 Vol.3 No.1

A 4kW RS840 CO2 laser with a powder auto-feeding apparatus has been used to deposit multiple overlapping tracks of Ni-base superalloy on to low carbon steel. It was found that the surface roughness(turbulence) of an overlapped cladding layer decreased with the increase of the overlapping ratio in an oscillating manner. When the overlapping ratio had values of 0.62, the surface turbulence was lowest. Overlapping ratio offer significant potential for improvement of materials surface properties such as corrosion performance and wear resistance. This paper reports that the overlapping ratio shows best corrosion resistance. The tensile residual stresses generated at the higher overlapping ratio(>0.45) and the element concentration of Fe increased in the surface layer at the lower overlapping ratio(<0.45) may lead to worse corrosion resistance.

응집공정 개선을 위한 Streaming Current Detector(SCD)의 적용

한무영,유재오,한정철 경희대학교 산학협력기술연구원 1996 산학협력기술연구논문집 Vol.2 No.-

The determination of an optimal and economical coagulant dosage is a crucial problem in water treatment plants: low dosage generally yields a poor removal of raw water turbidity, whereas high dosage leads to sludges which are difficult to dewater. Existing dosage control methods such as jar test, computer controlled equation, zeta potential measurement have shown some limitations in the control of coagulation process. Recent trend of dosage control technology in the developed country is the use of SCD(Streaming Current Detector). SCD is an equipment which continuosely detects the surface charge of particles which are subject to vary with the addition of coagulant. In this study, a technique using SCD is tested and evaluated for the possible control of coagulation process in a water treatment plant. In a bench scale test, the method using jar test is compared with SCD method. Some advantages and disadvantages of SCD are discussed and sensitivity of SCD reading to several water quality parameters is examined. In a pilot scale test using a rapid mixing unit, both SCD and zeta meter reading are measured and compared. Both readings gave similar trends as the coagulant dosage, however, SCD is proven to be more useful because it can be measured on-line. Finally, in a full scale test, SCD is measured at an operating water treatment plant. SCD has the capability of detecting the variation of water quality as well as some problems resulting from clogging of sensors. Overall, SCD technique is proven to be useful and to give some scientifically sound basis for optimum coagulant control in a water treatment plant.

여고생의 BMI와 체력과의 상관관계

이광무,고기준,한재웅,김태운,김종원 釜山大學校 附設 體育科學硏究所 1998 體育科學硏究所 論文集 Vol.14 No.-

The purpose of this study was to investigate the correlation of BMI and physical fitness in high school girls. The subjects were high school girls(n=295). The measurement items are physical fitness, physique, physique index(BMI : Body Mass Index). The conclusion of this study was as follows; 1. The record of 100M sprint, standing long jump, and sit ups showed a slack downward curve(low record) as BMI rises. 2. The record of softball showed a slack upward curve(high record) as BMI rises. 3. The record of 800M run, sit-ups and softball throw, from the top to the bottom. 4. The order of correlation between BMI and physical fitness was, flexed-arm hang, 100M sprint, standing long jump, 800M run, sit-ups and softball throw, from the top to the bottom. Therefore, we concluded that correlation BMI and physical fitness showed not so high.

Baculovirus를 이용한 Aujeszky's Disease Virus gⅢ 단백질 발현

송재영,이중복,현방훈,박종현,김병한,권창희,전무형,안수환 충남대학교 생물공학연구소 1993 생물공학연구지 Vol.3 No.-

The g Ⅲ gene located in U_L region of Yangsan strain, a field isolate of Aujeszky's disease virus (ADV) in Korea, was cloned into pTZ18R and sequenced. The gⅢ gene consisting of 1,437 nucleotides showed 98% sequence homology with that of Becker strain, a reference strain of ADV. The gene encoding gⅢ of Yangsan strain was placed under the control of Autographa californica nucleopolyhedrosis virus (AcNPV) polyhedrin promoter, and expressed by the derived recombinant baculovirus using Spodoptera frugiperda 9 (Sf9) cells. The expressed gⅢ was a protein with molecular weight of 72kd determined by immunoprecipitation and Western blotting assay using anti-ADV polyclonal antibodies and anti-gⅢ monoclonal antibody. The partially purified gⅢ protein was utilized as antigen in the radial immunodiffusion enzyme assay (RIDEA) to detect to specific antibody against ADV in pig sera. The results indicated that the sensitivity of RIDEA with the recombinant gⅢ protein antigen (98%) was as high as that with the conventional glycoprotein antigen extracted from the ADV infected cells. In addition, the false positive and false nagative reactions in gⅢ RIDEA were significantly reduced than the conventional glycoprotein RIDEA as judged from the results of standard serum neutralization test.

포러스콘크리트의 기초물성에 미치는 시멘트페이스트의 유동성 및 진동다짐시간의 영향에 관한 실험적 연구

김무한,백용관,최영욱,강석표,김재환,이성일 忠南大學校 産業技術硏究所 2001 산업기술연구논문집 Vol.16 No.2

This study analyzed the influence of paste fluidity and vibration time for fundamental properties of porous concrete. Results of this study were shown as follows: 1) Even if target void ratio is same, void ratio and compressive strength of porous concrete is different according to w/c, paste flow and vibration time. So, In case of target void ratio, we must consider the influence of w/c, past flow and vibration time. 2) Though w/c and vibration time is same, as paste flow increase, all void ratio, continuous void ratio, and compressive strength decrease and difference between upper and lower void ratio increase. 3) Though w/c and paste flow is same, as vibration time increase, all void ratio and continuous void ratio decrease and difference between upper and lower void ratio increase. Also, compressive strength increase by 10 seconds and decease after 10 seconds. 4) As types of superplasticizer is different, all void ratio, continuous void ratio, and compressive strength is different. So, we must give consideration to paste fluidity and vibration time in order that increase of strength of porous concrete and distribution of uniform void.

알카리성 부여제 도포에 의한 중성화된 콘크리트의 알카리성 회복성능에 관한 실험적 연구

김무한,권영진,강석표,유재강,이강우 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.1

Concrete is the most commonly used material in construction field and it is the permanent construction material with respect to civil property. But, if concrete loses its alkalinity by CO2 gas, it loses its structural characteristics and results in total collapse in construction field. Therefore. it is needed to be studied the alkali-recovery performance by alkalization agent on carbonated concrete by accelerated carbonation test. In this paper, we investigate recovery performance by impregnating alkalization agent in carbonated concrete, then we evaluate alkali maintenance performance by pH survey in each kinds of finishing materials. The results of this paper can be summarized as follows. 1)Carbonated concrete under pH 10 was recovered its alkalinity to pH 11 at first stage by spreading alkalization agent on its outer surface. 2)After spreading alkalization agent, there is a difference due to types of moreover effect of anti-rust paint and ordinary cement paste were excellent.

비복신경 전도검사의 신뢰도

이경무,변재현,장요한 충북대학교 의과대학 충북대학교 의학연구소 2003 忠北醫大學術誌 Vol.13 No.2

연구목적: 임상 신경연구에 있어서 신경전도검사의 사용이 증가되고 의료비용 증가에 따른 의료행위의 질에 대한 관심이 높아진다는 관점에서 신경전도검사 결과치의 신뢰도에 대한 관심이 높아지고 있다. 이에 신경전도검사의 결과치 중에서 가장 신뢰도가 낮다고 알려진 비복신경에 대한 검사·재검사 및 검사자간 신뢰도와 정상 참고치를 알아보고자 하였다. 대상 및 방법: 말초 신경병증을 의심할 만한 임상증세가 없는 건강한 성인 30명을 대상으로 두 명의 검사자가 각각 한시간 간격으로 비복신경의 기시 잠시, 정점 잠시, 진폭을 구하였고, 첫 번째 검사자는 두 시간 후에 동일 대상을 한번 더 검사하였다. 피어슨 상관계수를 이용하여, 검사·재검사 및 검사자간 신뢰도를 구하였다. 결과: 검사·재검사와 검사자간 신뢰도 평가 결과 base to peak amplitude와 peak to peak amplitude는 신뢰도가 낮았고, 기시 잠시와 정점 잠시는 신뢰도가 높았다. 또한 peak to peak amplitude가 base to peak amplitude보다 신뢰도가 높았고, 기시 잠시가 정점 잠시보다 신뢰도가 높았다(P< 0.01). 정상 참고치는 peak to peak amplitude가 8.67 μV, 기시 잠시가 3.24 ms이었다. 결론: 비복신경 전도검사에서 잠시는 검사·재검사 및 검사자간에서 높은 신뢰도를 보여주었으나, 진폭은 잠시에 비하여 신뢰도가 낮았다. 따라서, 비복신경 전도검사시 신뢰도를 더욱 높이기 위한 표준화된 검사방법이 필요하리라고 생각된다. Purpose: Nerve conduction studies play an important role in clinical practice and research. Given their widespread use, reliability of tests merits careful attention. The objective of this study is to establish the Intra-tester and Inter-tester reliability and normal values of sural nerve conduction study. Materials and Methods: We assessed Intra-tester and Inter-tester reliability of sural nerve measures of amplitude, onset latency, and peak latency. Thirty healthy adults without the clinical signs and symptoms of peripheral neuropathy were evaluated with sural nerve conduction study. Tests were performed on one leg of each subject twice, once by each tester. Tests were performed by one of the two testers on once more 2 hours later. Reliability was assessed with Pearson correlation coefficient. Results: In the Intra-tester and Inter-tester examination, the latencies of the sural nerves showed high correlation. But, amplitudes showed poor correlation(P< 0.01). Normal values of the peak to peak amplitude and the onset latency were 8.67 μV and 3.24 ms. Conclusion: Measures of onset latency and peak latency had higher reliability than amplitude. Of the variables, the onset and peak latency of sural conduction can be used as reliable measures with reasonable Intra-tester and Inter-tester reliability.

PVA-ECC를 활용한 Half PC 복합체의 역학적 특성에 관한 실험적 연구

김재환,김영덕,김갑수,조봉석,장종호,김무한 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

ECC represents one particular class of HPFRCC, which are defined by an ultimate strength higher than their first cracking strength and the formation of multiple cracking during the inelastic deformation process. This study is to provide the fundamental data for the development of hybrid construction method such as the half PC(Precast concrete) reinforced by PVA-ECC, the mechanical properties of half PC according to the alteration of properties of PVA-ECC in terms of the type of fiber, Vr, S/M, placing height of PVA-ECC, are experimentally investigated. As the results. it is found that the half PCs of PVA-ECC have very higher mechanical performance in terms of yield load, strain capacity beyond yield point and maximum flexural load than that of mortar. Also, flexural crack in the half PCs of PVA-ECC are not localized at first crack and are growed to many micro crack, especially multiple cracking in specimen of P(12)-30-0.1ㆍ3 occurred.