전이금속촉매를 사용한 4,4-비스[(트리플로로아세톡시)메틸]-1,6-헵타디인의 고리화중합을 통하여 고분자 반복단위 내에 고리구조를 갖는 공액구조 고분자인 폴리{4,4-비스[(트리플로로아세톡시)메틸]-1,6-헵타디인}(PBTFMH)을 합성하였다. 일반적으로 몰리브데늄 계 촉매를 사용한 경우의 중합수율이 텅스텐 계 촉매 를 사용한 경우의 그것보다는 높게 나타났다. 합성한 고분자는 중합과정중의 가교화반응으로 대부분 유기 용매에 용해하지 않았다. 고분자의 IR 스펙트럼에서는 단량체의 그것에서 나타났던 아세틸렌의 C≡C, 및 ≡C-H 신축진동띠를 보여주지 않았다. 이 고분자는 XRD 회절분석 결과 대부분 무정형상임이 밝혀졌다.

본 연구에서는 저온 소성 굴 패각의 재활용을 위한 기초적 연구로서 메조코즘 실험을 통해 저온 소성 굴 패각의 피복에 따른 연안 오염 퇴적물의 성상 변화를 조사하였다. 이를 위해 350 °C에서 소성시킨 굴 패각을 연안 오염 퇴적물에 피복하여 직상수와 간극수의 성상변화를 분석하는 메조코즘 실험을 수행하였다. 실험 결과, 굴 패각의 피복에 의해 수층과 퇴적층이 분리되었기 때문에 직상수의 산화 환원전위(ORP) 증가 및 DIN 중의 NH3-N의 비율의 감소가 실험구에서 관측되었다. 실험구의 DIP의 농도는 대조구와 비교하여 유의한 차이를 확인하기 어려웠다. 굴 패각의 피복에 의한 퇴적물의 총유기탄소(TOC)는 감소하였으며, 산휘발성황화물(AVS)은 저온 소성 굴 패각의 황화물 흡착 능력으로 인해 최대 50%까지 감소한 것으로 확인되었다. 본 연구의 결과로부터 저온 소성 굴 패각은 연안 오염 퇴적물의 정화를 위해 이용될 수 있는 재료인 것으로 결론 지을 수 있다.

In aluminum brazing processes, corrosive flux, which is used in preventing oxidation, is currently raising environmental concerns because it generates many pollutants such as dioxin. The brazing process involving noncorrosive flux is known to encounter difficulties because the melting temperature of the flux is similar to that of the base material. In this study, a new brazing filler material is developed based on aluminum and non-corrosive flux composite powder. To minimize the interference of consolidation aluminum alloy powder by the flux, the flux is intentionally embedded in the aluminum alloy powder using a mechanical milling process. This study demonstrates that the morphology of the composite powder can be varied according to the mixing process, and this significantly affects the relative density and mechanical properties of the final filler samples.

한강수계 남한강의 보 (강천보, 여주보, 이포보) 공사 후 수변부 여울 구간의 물리적 환경의 변화에 따른 유수성 저서동물의 군집 변화를 확인한 결과 다음과 같은 결론을 얻었다. 첫째, 보에 의한 여울구간의 소실은 유속, 하상 등 물리적 환경의 변화를 야기하여 수질요인과는 독립적으로 수생태계에 영향을 미칠 수 있다. 둘째, 남한강 보 구간의 수변부 물리적 서식환경의 복합적인 변화는 유수성 분류군의 군집구성에 영향을 미친 것으로 판단된다. 셋째, 저서성 대형무척추동물 유수성 지표 후보종 157 분류군은 수생태계 변화의 원인 분석을 비롯한 하천 수생태계 복원 및 재자연화 등에 유용한 지표로 활용될 수 있을 것으로 기대된다. 넷째, 향후 유속변화에 대한 수생태계 영향을 면밀하게 파악하기 위해서는 분류군별 유속에 대한 저항성 또는 선호도를 바탕으로 한 지표연구가 필요할 것으로 사료된다.

PURPOSES : This study was conducted to develop a traffic accident prediction model using traffic accident data and management and service evaluation data on bus companies in Busan, and to determine the possibility of establishing customized traffic accident prevention measures for each company. METHODS: First, we collected basic data on the characteristics of urban bus traffic accidents and conducted basic statistical analysis. Then, we developed traffic accident prediction models using Poisson regression and negative binomial regression to examine the characteristics of major items of management and service evaluation affecting traffic accidents. RESULTS : The Poisson regression model showed overdispersion; hence, the negative binomial regression model was selected. The results of the traffic accident prediction model developed using negative binomial regression are acceptable at 95% confidence level (a = 0.05). CONCLUSIONS : The traffic accident prediction model indicates that the management of the traffic record system and internal and external management items in service evaluation have a significant effect on the reduction of traffic accidents. In particular, because human factors are the main cause of traffic accidents, bus traffic accidents are expected to greatly decrease if drivers' dangerous driving behaviors are effectively controlled by bus companies.

페로브스카이트 양자점에 물을 첨가하여 절대양자효율과 안정성이 향상되는 현상에 대해 연구를 수행하였다. 수분에 의해 특성이 저하되는 페로브스카이트 양자점의 일반적인 성질과 다르게 절대양자효율과 안정성이 향상되는 원인을 여러 가지 분석장비를 활용해 분석하였다. 물을 첨가했을 때 결정성이 향상되는 것을 확인하였다.

Recently the incidence of rollover accidents has increased due to the increase of SUV, and the probability of occupant injury in rollover accidents is very high, so research is needed accordingly. In this study, PC-CRASH, which is a program used for traffic accident analysis, is used for checking rollover speed and rollover angle of each situation in case of rollover accident, and applied to design variables of LS-DYNA which is finite element analysis program, so deformation displacements of roof according to collision velocity and angle were derived. Also, it is possible to predict rollover vehicle speed by using the derived value and the measured deformation displacement of roof in actual rollover accident, and it is possible to reconstruct accident more accurately by applying to PC-Crash which is traffic accident reconstruction program, so it is thought that it can be utilized analyzing traffic accident usefully.

국제해상충돌방지규칙과 해사안전법은 항법의 개념과 그 항법규정을 언제부터 적용하여야 하는지에 대한 요건을 구체적으로 정하고 있지 않다. 항법 적용의 시점은 선박에 대한 항법상 권리와 의무의 관계를 설정하는 기준을 결정하는 것으로서 매우 중요한 의미를 지니고 있다. 실제로 선박 충돌사고가 발생한 경우 항법 적용의 시점에 따라 양 선박 사이에 적용될 항법이 결정된다. 이로 인해서 선박 상호간에 피항선과 유지선의 관계가 결정되고, 해양안전심판원에서는 항법 준수 여부에 따른 과실비율을 산정하고 있다. 실무에서선박의 운항자들이 선박의 충돌을 방지하고 항해의 안전을 확보하기 위해서 항법을 준수하고 있다는 점을 감안할 때, 선박 상호간 항법 적용의 개시시점을 명확하게 규정될 필요가 있다. 따라서 이 논문에서는 최근 해양안전심판원의 재결을 중심으로 항법 적용의 시점에 대한 합리적인 해석 방향을 제시하고자 한다. 이를 위해 재결사례의 주요 쟁점과 내용을 살펴보고, 항법의 일반적 의의와 적용원칙을 검토하고자 한다. 또한 학설과 재결을 중심으로 항법 적용의 시점을 결정하기 위해 고려하여야 할 요건을 면밀히 검토하고자 한다. 이를 통해서 선박의 조우 상태에 따른 합리적인 항법 적용의 시점을 제시하고자 한다.

Sludge transporting pipes in wastewater treatment plant are easy to be clogged with struvite when the digested sludge and dehydrated filtrate are transported through the pipes, which lowers the efficiency of sludge treatment system in a WWTP. pH is one of the most important factors in struvite formation, and carbon dioxide separated from biogas can be used to control pH and struvite formation. By controlling pH, the amount of dehydrating agent can be reduced by about 10%, which saves the budget for facility maintenance. As CO2 is reused and dehydrating chemicals are saved, the approach can contribute to global warming gas reduction.

Corrosion inhibitors including calcium hydroxide have been used to prevent corrosion in the pipes for tap water supply. The corrosion index (i.e., Langelier Index) differs by area and water quality. The corrosion indices of the areas studied differed by more than 2.0. The ‘homogenized’ calcium hydroxide was added to the treated water at the K water treatment plant, in order to increase the value of the corrosion index and the concentration of calcium. As the result, the concentration of calcium was increased while the turbidity and pH changed little. The corrosion rate of the tap water with the 'homogenized' calcium hydroxide could be slowed down pretty much. The results suggested that the technology of 'homogenization' of calcium hydroxide can applied to tap water and desalinated water to prevent corrosion in water pipes even in corrosive pipes.

Bird screen meshes are installed at the air inlet and outlet ducts of spent fuel storage casks to inhibit the intrusion of debris from the external environment. The presence of these screens introduces an additional resistance to air flow through the ducts. In this study, a porous media model was developed to simplify the bird screen meshes. CFD analyses were used to derive and verify the flow resistance factors for the porous media model. Thermal analyses were carried out for concrete storage cask using the porous media model. Thermal tests were performed for concrete casks with bird screen meshes. The measured temperatures were compared with the analysis results for the porous model. The analysis results agreed well with the test results. The analysis temperatures were slightly higher than the test temperatures. Therefore, the reliability and conservatism of the analysis results for the porous model have been verified.

PURPOSES: The permeable pavement type has been rapidly developed for solving problems regarding traffic noise in the area of housing complex and heavy rainwater drainage in order to account for the climate change. In this regards, the objective of this study is to figure out the characteristics of pavement types. METHODS: The laboratory test for deriving optimum asphalt content (OAC) was conducted using the mixtures of the permeable asphalt surface for the pavement surface from Marshall compaction method. Based on its results, the pavement construction at the test field was conducted. After that, the site performance tests for measuring the traffic noise, strength and permeability were carried out for the relative evaluation in 2 months after the traffic opening. The specific site tests are noble close proximity method (NCPX), Light falling deflectometer test (LFWD) and the compact permeability test. RESULTS : The ordered highest values of the traffic noise level can be found such as normal dense graded asphalt, drainage and porous structure types. In the results from LFWD, the strength values of the porous and drainage asphalt types had been lower, but the strength of normal asphalt structure had relatively stayed high. CONCLUSIONS: The porous structure has been shown to perform significantly better in permeability and noise reduction than others. In addition to this study, the evaluation of the properties and the determination of the optimum thickness for the subgrade course under the porous pavement will be conducted using ground investigation technique in the further research.

Many studies can now confirm that the body growth of youths aged 6 to 17 is increasing due to changes in dietary habits and lifestyles in Korea. If the growth of youths increase continuously, many companies that make chairs for youths must prepare anything. Youth's chairs, which are being produced at present companies, are produced by companies with multiple data. Looking at this chair, it may not fit the body of youths of the future. It is necessary to change the design dimension of the chair for that. In this research, we try to predict how the body of youths in the future will become bigger by using physical data of youths aged 6 to 17 years old. Then, using the predicted physical data, we will propose the dimensions of the design of the chair for youth.

One of the most performed actionin daily life is standing up from sitting position. As the population of the world is aging at the high rates, people may face problems with reduced muscle strength as well as psychological changes. This can lead elderly people having difficulties with standing up from chair. Now, with the aging trend worldwide, products are being developed that can support the lives of the elderly. This study examines the distribution of hip pressure in relation to the seating positions of the standing assistance seats under development to prevent standing up accidents in older adults. The currently developing standing assistant chair designed to tilt to a maximum angle of 25 degrees. At over 25°, design considers that older people are at risk of thrown back out of that force and that the forces exerted on their arms and legs can be a significant burden to older people. By considering danger of higher than 25° for older people which is experimented in the basis of static capturing approach in previous papers, it is experimented people with age group of 20~60 on 0° to 25° tilting angle on the basis of dynamic capturing method in order to pick convenient angle of inclination. Moreover, tried to find the optimum angle by comparing the hip pressure distribution when seated at the edge of the seat and at the center of the seat with the pressure distribution sensor.

Aircraft landing is a complex and challenging flight phase in which pilots are required to allocate attention efficiently to the surrounding environment. A comprehensive understanding of pilot situation awareness (SA) is needed for successful landing. This study was to predict pilot SA during landing using eye tracking data. The experiments were carried out with 5 repetitive simulated landings for four expert and four novice pilots using eye tracking equipment. Three eye tracking features (visit frequency, dwell time ratio, scan path entropy) were developed for reflecting three level of SA model (perception, comprehension, projection). Prediction of SA was performed by developing multiple regression model. Visit frequency of expert pilots was 138%, 47%, 85%, 67%, 117%, and 91% higher than novice pilots in RPM, VVI, altimeter, heading, airspeed, and attitude areas of interest (AOIs) respectively; while 50% and 33% lower in runway and outside AOIs respectively. Dwell time ratio of expert pilots was 38% and 42% higher than novice pilots in runway and outside AOIs respectively; while 62%, 62%, and 65% lower in altimeter, airspeed, and attitude AOIs respectively. Scan path entropy of expert pilots was 33% higher than novice pilots in outside AOI; while 29% lower in attitude AOI. Coefficient of determination for the prediction model for SA was 80.6%. The results of this study can be used as objective data of strategy establishment or training feedback for novice pilots.

A total of 594 reservoirs (17%), which are managed by KRC, equipped with earthquake-resistant facilities whereas remaining ones did not. In addition, reservoirs were placed without the effect of geological structures (i.e., fault and lineament). Therefore, development on technique for alleviating the potential hazards by natural disasters along faults and lineaments has required. In addition, an effective reinforcement guideline related to the geological vulnerabilities around reservoirs has required. The final goal of this study is to suggest the effective maintenance for the safety of earth fill dams. A radius 2 km, based on the center of the reservoir in the study area was set as the range of vulnerability impacts of each reservoir. Seismic design, precise safety diagnosis, seismic influence and geological structure were analyzed for the influence range of each reservoir. To classify the vulnerability of geological disasters according to the fault distribution around the reservoir, evaluation index of seismic performance, precise safety diagnosis, seismic influence and geological structure were also developed for each reservoir, which were a component of the vulnerability assessment of geological disasters. As a result, the reservoir with the highest vulnerability to geological disasters in the pilot district was analyzed as Kidong reservoir with an evaluation index of 0.364. Within the radius of 100km from the epicenter of the Pohang earthquake, the number of agricultural infrastructure facilities subject to urgent inspections were 1,180 including reservoirs, pumping stations and intakes. Four reservoirs were directly damaged by earthquake among 724 agricultural reservoirs. As a result of the precise inspection and electrical resistivity survey of the reservoir after the earthquake, it was reported that cracks on the crest of reservoirs were not a cause of concern. However, we are constantly monitoring the safety of agricultural facilities by Pohang aftershocks.

This study is focused on manganese (Mn(II)) removal by ozonation in surface water. Instant ozone demand for the water was 0.5 mg/L in the study. When 0.5 mg/L of Mn(II) is existed in water, the optimum ozone concentration was 1.25 mg/L with reaction time 10 minutes to meet the drinking water regulation. The ozone concentration to meet the drinking water regulation was much higher than the stoichiometric concentration. The reaction of soluble manganese removal was so fast that the reaction time does not affect the removal dramatically. When Mn(II) is existed with Fe, the removal of Mn(II) was not affected by Fe ion. However As(V) is existed as co-ion the removal of Mn(II) was decreased by 10%. Adding ozone to surface water has limited effect to remove dissolved organic matter. When ozone is used as oxidant to remove Mn(II) in the water, the existing co-ion should be evaluated to determine optimum concentration.

고등 복합재료 구조물 제작에 적용되는 고온경화용 에폭시 수지 시스템 경화물의 물리적 특성을 연구하였다. 고온경화용 에폭시 수지 경화물의 표면 몰폴로지는 저온경화용 수지 시편의 표면과는 달리 균일한 몰폴로지를 보여주었다. 이 수지 경화물의 열중량분석 결과 300 oC까지는 무게감소가 거의 없는, 즉 열적으로 매우 안정한 것으로 나타났는데, 이는 높은 가교화밀도에 기인한 것이다. 300-500 oC 영역에 서 급격한 무게감도는 매트릭스 수지의 본격적인 열분해에 기인한 것이다. 시편의 인장 및 압축 특성, 열 변형온도, 밀도, 부피수축 등의 특성을 측정하고 평가하였다.

PURPOSES : A geo-grid pavement, e.g., a stress-absorbing membrane interlayer (SAMI), can be applied to an asphalt-overlay method on the existing surface-pavement layer for pavement maintenance related to reflection cracking. Reflection cracking can occur when a crack in the existing surface layer influences the overlay pavement. It can reduce the pavement life cycle and adversely affect traffic safety. Moreover, a failed overlay can reduce the economic value. In this regard, the objective of this study is to evaluate the bonding properties between the rigid pavement and a SAMI by using the direct shear test and the pull-off test. The predicted fractural energy functions with the shear stress were determined from a numerical analysis of the moving average method and the polynomial regression method. METHODS : In this research, the shear and pull-off tests were performed to evaluate the properties of mixtures constructed using no interlayer, a tack-coat, and SAMI with fabric and without fabric. The lower mixture parts (describing the existing pavement) were mixed using the 25-40-8 joint cement-concrete standard. The overlay layer was constructed especially using polymer-modified stone mastic asphalt (SMA) pavement. It was composed of an SMA aggregate gradation and applied as the modified agent. The sixth polynomial regression equation and the general moving average method were utilized to estimate the interlayer shear strength. These numerical analysis methods were also used to determine the predictive models for estimating the fracture energy. RESULTS: From the direct shear test and the pull-off test results, the mixture bonded using the tack-coat (applied as the interlayer between the overlay layer and the jointed cement concrete) had the strongest shear resistance and bonding strength. In contrast, the SAMI pavement without fiber has a strong need for fractural energy at failure. CONCLUSIONS : The effects of site-reflection cracking can be determined using the same tests on cored specimens. Further, an empiricalmechanical pavement-design analysis using the finite-element method (FEM) must be done to understand the appropriate SAMI application. In this regard, the FEM application analysis and bonding property tests using cored specimens from public roads will be conducted in further research.