슬립폼공법 적용된 동절기 케이슨의 온도에 따른 응결시간 및 압축강도

김봉주,김재훈,김찬수,조호규,Kim,Bong-Joo,Kim,Jae-Hun,Kim,Chan-Soo,Jo,Ho-Kyoo 한국방재학회 2006 한국방재학회논문집 Vol.6 No.1

항만공사에 사용되는 케이슨의 제작은 slip-form을 사용한 연속타설공법을 적용하고 있다. 국내 공사에서는 동절기에도 소요의 압축강도를 발현하기 위해서 양생시간의 조절과 slip-form 자체에 온도조절이 가능한 가열보온기기를 설치하여 시공하고 있다. 외기온에 따른 최적 양생온도 및 탈형시간을 추정하여 다음과 같은 결론을 도출하였다. 양생온도 <TEX>$30^{\circ}C$</TEX>에서 6시간의 양생시간을 거쳐 탈형되는 것이 압축강도의 발현이나 탈형의 부착 등의 문제가 없는 것으로 판단된다. In the harbor construction work, caisson is made by slip-form method and curing temperature of caisson concrete need heating in the low-temperature. To get the setting time and compression strength of slip-form method applied caisson at various curing temperature. The curing temperature is divided to the temperature of slip-form and the temperature of second curing curtain. In consideration of setting time, compression strength of concrete and form-removal time, the best temperature is <TEX>$25^{\circ}C$</TEX> at 6 hours slip-form curing time.

AEB 시험평가 방법에 관한 연구

김봉주,이선봉,Kim, BongJu,Lee, SeonBong 한국자동차안전학회 2018 자동차안전학회지 Vol.10 No.2

Currently, sharp increase of car is on the rise as a serious social problem due to loss of lives from car accident and environmental pollution. There is a study on ITS (Intelligent Transportation System) to seek coping measures. As for the commercialization of ITS, we aim for occupancy of world market through ASV (Advanced Safety Vehicle) related system development and international standardization. However, the domestic environment is very insufficient. Core factor technologies of ITS are Adaptive Cruise Control, Lane Keeping Assist System, Forward Collision Warning System, AEB (Autonomous Emergency Braking) system etc. These technologies are applied to cars to support driving of a driver. AEB system is stop the car automatically based on the result decided by the relative speed and distance with obstacle detected through sensor attached on car rather than depending on the driver. The purpose of AEB system is to measure the distance and speed of car and to prevent accident. Thus, AEB will be a system useful for prevention of accident by decreasing car accident along with the development of automobile technology. This study suggests a scenario to suggest a test evaluation method that accords with domestic environment and active response of international standard regarding the test evaluation method of AEB. Also, by setting the goal with function for distance, it suggests theoretic model according to the result. And the study aims to verify the theoretic evaluation standard per proposed scenario using car which is installed with AEB device through field car driving test on test road. It will be useful to utilize the suggested scenario and theoretical model when conducting AEB test evaluation.

단안카메라를 활용한 ACC 시험평가 방법에 관한 연구

김봉주,이선봉,Kim, Bong-Ju,Lee, Seon-Bong 한국자동차안전학회 2020 자동차안전학회지 Vol.12 No.3

Currently, the second level of the six stages of self-driving technology, as defined by SAE, is commercialized, and the third level is preparing for commercialization. The purpose of ACC is to be evaluated as a system useful for preventing and preventing accidents by minimizing driver fatigue through longitudinal speed control and relative distance control of the vehicle. In this regard, for the study of safety assessment methods in the practical environment of ACC. Distance measurement method using monocular camera and data acquisition equipment such as DGPS are utilized. Based on the evaluation scenario considering the domestic road environment proposed by the preceding study, the relative distance obtained from equipment such as DPGS and the relative distance using a monocular camera in the actual test is verified by comparing and analyzing the safety assessment. The comparison by scenario results showed a minimum error rate of 3.83% in Scenario 1 and a maximum of 14.61% in Scenario 6. The cause of the maximum error is that the lane recognition is not accurate in the camera image and irregular operation conditions such as rushing in or exiting the surrounding area from the walkway. It is expected that safety evaluation using a monocular camera will be possible for other ADAS systems in the future.

국내도로 환경을 고려한 ACC 시험평가 방법에 관한 연구

김봉주,이선봉,Kim, BongJu,Lee, SeonBong 한국자동차안전학회 2017 자동차안전학회지 Vol.9 No.4

With automobiles sharply increasing worldwide, we are faced with serious social problems such as traffic accidents, traffic jams, environmental pollution, and economic inefficiency. In response, research on ITS is promoted mainly by regions with advanced automotive industry such as the US, Europe, and Japan. While Korea is working to get ahead to take global market through developing and turning into global standards systems related to ASV(Advanced Safety Vehicle), the country is not excellently prepared for such projects. The purpose of ACC is to control the vehicle's longitudinal speed and distance and minimize driver workload. Such a system should be useful in preventing accidents, as it reduces driver workload in the 21st-century world of telematics created by the development of automobile culture industry. In this light, the thesis presents a method to test and evaluate ACC system and a mathematical method to assess distance. Furthermore, for the proposed test and evaluation, theoretical values are tested with vehicle test and a database is acquired, by using vehicles equipped with an ACC system. We proposed the scenarios suitable for the domestic environment and conducted the actual road test. Theoretical evaluation criteria for developing ACC system may be employed and scenario-specific evaluation methods may find their useful application through testing the formula proposed by comparing the database and the mathematical method. and, many companies are expected to utilize the scenario in the developing stage of ACC, and be able to employ as a verification method by harnessing theoretical formula before a road test.

마이크로웨이브를 이용한 금정광 내 금 용출 효율 증가 기작

김봉주,권장순,고용권,박천영,Kim, Bong-Ju,Kwon, Jang-Soon,Koh, Yong-Kwon,Park, Cheon-Young 대한자원환경지질학회 2020 자원환경지질 Vol.53 No.2

본 연구에서는 금정광내 금회수율을 증진하고자 마이크로웨이브 전처리방법을 이용하여 티오요소용출 실험을 수행하였다. 이에 본 연구에서는 먼저 마이크로웨이브를 이용하여 금정광 시료 내 황철석의 분해에 따른 광물상 변화를 관찰하였다. 마이크로웨이브의 조사시간이 증가함에 따라 시료의 온도는 증가하였고, 황철석 내 S가 SO₂로 변환되어 시료 내 S의 함량이 감소되었다. X-선 회절분석 및 주사전자현미경 에너지 분산 분광분석을 통해 황철석은 자류철석과 적철석으로 변환되었으며, 미세균열이 발달된 다공질의 형태로 변질되었음을 확인할 수 있었다. 다양한 조건의 티오요소 혼합 용매를 이용하여 시료의 광물상변화에 따른 금 용출효율을 측정한 결과, 마이크로웨이브 조사시간 증가 및 용출실험 조건 내 용매의 농도 증가에 따라 용출효율이 증가하였다. 결론적으로, 마이크로웨이브를 활용한 금정광 조사는 시료 내 금의 최대용출효율과 용출속도를 증가시켰으며, 티오요소 용매제는 용출속도상수를 증가시켜주는 역할을 하였다. In this research, we investigate the effect of microwave pretreatment on the recovery of gold from the gold concentrates by thiourea leaching. The changes in mineral phases by decomposition of pyrites in the gold concentrates using microwave were observed, and the result of microwave irradiation showed that the temperature of the irradiated sample increases with increasing irradiation time. With the reaction of temperature increases, Sulfur (S) in pyrites was converted to sulfur dioxide (SO₂), and then the content of S in the sample was reduced. The analytical results of XRD and SEM-EDS showed that pyrites are converted to magnetite and hematite, and its surfaces are changed to a porous shape where micro-cracks are developed. The Au leaching efficiency from the irradiated gold concentrates using thiourea-mixed solvent increased with the increases of irradiation time and solvent concentration. The experimental results considering leaching parameters indicate that the mechanism of microwave irradiation increases the maximum leaching efficiency and leaching rate of the gold concentrates, and the solvent does a role for the increasing of leaching rate constant.

전기분해법을 이용한 금정광내 Te 회수 특성

김봉주,조강희,조지유,최낙철,박천영,Kim, Bong-Ju,Cho, Kang-Hee,Jo, Ji-Yu,Choi, Nag-Choul,Park, Cheon-Young 대한자원환경지질학회 2014 자원환경지질 Vol.47 No.6

In order to obtain pure metallic Te from gold concentrate, roasting treatment, hypochlorite leaching, Fe removal and electrolysis experiments were carried out. The contents of Au, Ag and Te from the concentrate sample and roasted sample were much more soluble in the hypochlorite solution than in aqua regia digestion, whereas the metals Pb, Zn, Fe and Cu were easier to leach with the aqua regia than the hypochlorite. With the addition of NaOH in the hypochlorite leaching solution prior to electrolysis, the Fe removal rate achieved was only 96% in the concentrate sample, while it reached 98% in the roasted sample. The results of electrolysis for 240 min, 98% of the metallic copper was recovered from the concentrate sample, while 99% was obtained from the roasted sample due to the removal of S by roasting. The amount of anode slime was also greater in the electrolytic solution with the roasted sample than with the concentrate sample. The results on the anode slime after the magnetic separation process showed the amount of metallic pure native tellurium recovered was greater in the roasted sample than in the concentrate sample. 금 정광으로부터 순수한 금속 형태의 Te을 얻기 위하여 소성처리, 차아염소산 용출, Fe 제거 및 전기분해실험을 수행하였다. 정광 및 소성시료에 포함되어 있는 Au, Ag 및 Te는 왕수보다 차아염소산에서 더 많이 용해된 반면에 Pb, Zn, Fe 및 Cu는 차아염소산보다는 왕수에서 더 많이 용출되었다. 전기분해하기 전, 차아염소산 용출-용액에 NaOH를 첨가한 결과 Fe가 정광시료에서 96% 제거되었지만 소성시료에서는 98% 제거되었다. 전기분해실험을 240분 동안 수행한 결과, 금속 구리가 정광시료에서 98% 회수된 반면에 소성시료에서 99%나 회수되었다. 이는 소성처리에 의하여 S가 제거되었기 때문이다. 양극 슬라임도 정광시료보다 소성시료의 전해질 용액에서 더 많이 생성되었다. 양극 슬라임을 자력선별한 결과 순수한 자연금속 형태의 텔루륨이 정광시료보다 소성시료에서 더 많이 회수되었다.

한국증권시장(韓國證券市場)의 수익률예측(收益率豫測) 가능성(可能性)에 대한 연구(硏究)

김봉주,Kim, Bong-Ju 한국재무관리학회 1994 財務管理論叢 Vol.1 No.2

건설기능인력 자격 및 직급체계 구축방안 제안

김봉주,정명호,현창택,구교진,문현석,Kim, Bong-Ju,Jung, Myung-Ho,Hyun, Chang-Taek,Koo, Kyo-Jin,Moon, Hyun-Seok 한국건설관리학회 2006 건설관리 : 한국건설관리학회 학회지 Vol.7 No.5

건설기능인력은 최종 생산자로서 생산성 및 품질에 직접적으로 영향을 미치는 중요한 요소임에도 불구하고 방치된 채 고령화되고 고갈되는 양상을 띄고 있다. 이는 궁극적으로 젊은 기능인력의 건설사업 회피에서 기인한 것이다. 따라서 본 연구의 목적은 양질의 기능인력 수급을 위해서 기능인력의 자격 및 직급체계를 제안하여 건설기능인력 시장에 젊은 기능인력을 끌어들이는데 있다. 먼저, 본 연구에서는 국내 건설기능인력 체계의 현황과 문제점을 연구하였다. 그리고 전문가와의 면담과 독일, 호주의 사례 연구를 통해 국내에 적용 가능한 자격 및 직급체계 구축방안을 제안하였다. 본 연구에서 제안하고 있는 건설기능인력의 자격 및 직급체계의 활성화는 기능인력이 단순한 노무라는 이미지에서 탈피하여 전문분야임을 인식시킬 수 있으며, 젊고 유능한 기능인력을 건설산업으로 유입시킴으로써 건설기능인력의 생산성 향상, 전문성 강화, 고령화를 탈피시킬 수 있을 것으로 판단된다. 또한, 사회보장제도와의 연계를 통하여 고용안정화를 도모할 수 있을 것이다. The construction craft workers have been getting older and have become drained, in spite of the vital factor that it directly affects productivity and quality as a final producer. This situation in the construction industry is ultimately due to evasion of performances by young craft workers. Therefore, the aim of this study is to propose the certification and level system of construction craft workers and to extract young craft workers from the market for construction craft workers so as to supply and demand high quality of craft workers. First of all, the present status and problems of the domestic construction craft workers are considered in this study. Furthermore, the appropriate way to establish its certification and level system is suggested from the Interview with experts, as well as references of German and Australian case. The revitalization of certification and level system provided in this study is expected to ensure that the craft workers are not simple laborers, but are required the professional knowledge and skill. Besides, it will lead to strengthen specificity and to break from aging, by taking young and qualified craft workers into the construction industry. Also, it will promote an employment stability by connecting the social security system.

Cu 이온에 적응된 토착호산성박테리아를 이용한 폐광석으로부터 미생물용출 효율 향상

김봉주,위대웅,최낙철,박천영,Kim, Bong-Ju,Wi, Dae-Woong,Choi, Nag-Choul,Park, Cheon-Young 한국지하수토양환경학회 2012 지하수토양환경 Vol.17 No.4

This study was carried out to leach valuable metal ions from the mine waste ore using the adapted indigenous bacteria. In order to tolerance the heavy metals, the indigenous bacteria were repeatedly subcultured in the adaptation-medium containing $CuSO_4{\cdot}5H_2O$ for 3 weeks and 6 weeks, respectively. As the adaptation experiment processed, the pH was rapidly decrease in the adaptation-medium of 6 weeks more than the 3 weeks. The result of bioleaching with the adapted bacteria for 42 days, the pH value of leaching-medium in the 3 weeks tend to increased, whereas the pH of the 6 weeks decreased. In decreasing the pH value in the adaptation-medium and in the leaching-medium, it was identified that the indigenous bacteria were adapted $Cu^{2+}$ the ion and the mine waste ores. The contents of Cu, Fe and Zn in the leaching solution were usually higher leached in 6 weeks than 3 weeks due to the adaptation. Considering the bioleaching rates of Cu, Fe and Zn from these leaching solutions, the highest increasing the efficiency metal ion were found to be Fe. Accordingly, it is expected that the more valuable element ions can be leached out from the any mine waste, if the adapted bacteria with heavy metals will apply in future bioleaching experiments.

Comparative Study of KFM and EFM on Off-Axis Sputtered PZT Thin Film

김봉주,Bog G. Kim,Daeyoung Kwon 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.II

We have done a comparative study of Kelvin force microscopy (KFM) and electric force microscopy (EFM) on off-axis sputtered ferroelectric PZT thin films. KFM and EFM have been extensively used to characterize the domain image of ferroelectric thin films. However, the non-contact nature of KFM and the importance of interactions among tip, cantilever, and sample have not been fully explored to understand the domain imaging obtained in the experiment. Moreover, the surface screening due to the charging and depolarization field should also be carefully analyzed. In this paper, we present a comprehensive study of KFM and EFM on off-axis sputtered PZT thin films.