Recently, steel dampers are widely used as seismic reinforcement devices. Steel dampers have the advantage of being easy to manufacture and being able to absorb a lot of energy through stable hysteresis behavior. However, there is a possibility that the steel damper may be damaged due to fatigue caused by repeated seismic loads. In this study, the seismic performance of steel dampers and engineering plastic dampers with different physical characteristics were compared and analyzed. In addition, numerical analysis was performed on a hybrid damper that combines a steel damper and an engineering plastic damper. It is more effective to apply engineering plastic dampers to structures that experience significant displacement due to seismic loads. The behavior of hybrid dampers combining steel dampers and engineering plastic dampers is dominated by steel dampers. A hybrid damper in which an engineering plastic damper yields after a steel damper yields can effectively respond to various seismic loads and secure high ductility and excellent seismic performance.

The energy dissipation of inverted V-type eccentric steel braced frames can be achieved through the yielding of a slit link, through yielding of a number of strips between slits when the frame is subjected to inelastic cyclic deformation. On the other hand, the development of seismic resistance system without residual deformation is obtained by applying the superelasdtic shape memory alloy (SMA) material into the brace and link elements. This paper presents results from a systematic three-dimensional nonlinear finite element analysis on the structural behavior of the eccentric bracing systems subjected to cyclic loadings. A wide scope of structural behaviors explains the horizontal stiffness, hysteretic behaviors, and failure modes of the recentering eccentric bracing system. The accurate results presented here serve as benchmark data for comparison with results obtained using modern experimental testing and alternative theoretical approaches.

In this study, an incremental loading test of the HRS(Hybrid Rubber Slit) damper was additionally performed to define the physical characteristics according to the incremental test results, and an analytical study was performed according to the damping design procedure by selecting an example structure. As a result of performing seismic performance evaluation before reinforcement by selecting a RC structure similar to an actual school structure as an example structure, the story drift ratio was satisfied, but some column members collapsed due to bending deformation. In order to secure the seismic performance, the damping design procedure of the HRS damper was presented and performed. As a result of calculating the amount of damping device according to the expected damping ratio and applying it to the example structure, the hysteresis behavior was stable without decrease in strength, and the story drift ratio and the shear force were reduced according to the damping effect. Finally the column members that had collapsed before reinforcement satisfied the LS Level.

It is effective to apply hybrid damping device that combine separate damping device to cope with various seismic load. In this study, HRS hybrid damper(hybrid rubber slit damper) in which high damping rubber and steel slit plate are combined in parallel was proposed and structural performance tests were performed to review the suitability for seismic performance. Cyclic Loading tests were performed in accordance with criteria presented in KDS 41 17 00 and MOE 2019. As a result of the test, the criteria of KDS 41 17 00 and MOE2019 was satisfied, and the amount of energy dissipation increased due to the shear deformation of the high-damping rubber at low displacement. Result of performing the RC frame test, the allowable story drift ratio was satisfied, and the amount of energy dissipation increased in the reinforced specimen compared to the non-reinforced specimen.

철도소음은 도시지역의 철도건설과 유지에 가장 큰 장애 요소 중 하나이므로 보다 효과적으로 철도소음을 저감하기 위한 연구가 활발히 진행되고 있다. 방음터널은 철도소음을 저감할 수 있는 가장 효과적인 방법 중 하나이나, 하절기 높은 내부 온도 증가로 인하여 궤도좌굴 또는 전력, 신호 등 선로 설비의 안정성을 저하시킬 우려가 있다. 이러한 온도 상승 문제는 통기 형 방음판을 이용하여 해결할 수 있으나, 방음터널 적용 시의 소음저감 성능에 대한 연구는 미흡한 상황이다. 이 논문에서는 수치해석을 통하여 통기형 슬릿방음판의 효과적인 방음터널 적용 방법에 대한 연구 결과를 제시하였다. 수치해석은 음향해석 프로그램인 Pachyderm Acoustics으로 모델링한 복선 방음터널을 이용하여 수행하였다. 철도소음은 기존 연구결과를 이용하여 모사하였으며, 슬릿방음판의 적용 위치가 다른 6가지 경우에 대하여 소음저감 효과 변화를 검토하였다. 음향해석 결과 20% 정도 의 슬릿방음판 적용 시에도 철도소음을 최소 5dB 감소할 수 있는 것으로 나타났다.

In order to develop the compatible damping device in various vibration source, a hybrid wall-type damper combining slit and friction damper in parallel was developed. Cyclic loading tests and two-story RC reinforced frame tests were performed for structural performance verification. As a result of the 5-cyclic loading test according to KBC-2016 and low displacement cyclic fatigue test, The hybrid wall type damper increased its strength and the ductility was the same as that of the slit damper. In addition, As a result of the two-layer frame test, the reinforced frame had about twice the strength of the unreinforced frame, and the story drift ratio was satisfied to Life Safety Level.

One simple way of increasing the heat transfer for a fin-and-tube heat exchanger is to increase the fin surface area. In this study, a series of tests were conducted on wide slit fin heat exchangers having an increased fin area (Pl/Pt = 0.87), and the results were compared with those of standard slit fin heat exchangers (Pl/Pt = 0.6). Thermal performances of wide silt-finned samples were superior to those of standard slit fin samples. For one row configuration, the j factor of the wide slit fin sample was 11% larger, and the f factor was 33 % smaller than those of the standard slit fin sample. The difference decreased as the number of tube row increased, although wide slit fin sample always yielded superior performance, The reason was attributed to the many narrower slits formed on the wide fin sample. Furthermore, the effect of fin pitch on j and f factor was not significant, and j factor decreased with the increase of the number of tube row.

Large amounts of oily wastewater discharged from various industrial operations (petroleum refining, machinery industries and chemical industries) cause serious pollution in the aquatic environment. Although dissolved air flotation (DAF) separating oil pollutants using microbubbles represents current practice, bubble size cannot be selectively controlled, and lots of power is required to generate microbubbles. Therefore, to investigate performance of the DAF process, this study examined the distribution of different sizes of microbubbles resulting from changes in physical shear force via modifying shapes of a slit-nozzle without an additional power supply. Three types of slit-nozzles (different angle, shape and length of the slit-nozzle) were used to analyze the distribution of bubble size. At a slit angle of 60°, shear force was 4.29 times higher than a conventional slit, and particle size distribution (PSD) in the range between 2 and 20 μm more than doubled. Treatment efficiency of synthetic oily wastewater through the coagulation-DAF process achieved 90% removal of COD by injecting FeCl3 and PACl of 250 mg/L and 100 mg/L, respectively, and the same performance resulted using FeCl3 of 200 mg/L and PACl of 80 mg/L employing a slit-nozzle angle of 60°. This study shows that a coagulation-DAF process using a modified slit-nozzle can improve the pre-treatment of oily wastewater.

This study investigates the seismic performance of a hybrid seismic energy dissipation device composed of a viscoelastic damper and a steel slit damper connected in parallel. A moment-framed structure is designed without seismic load and is retrofitted with the hybrid dampers. The model structure is transformed into an equivalent simplified system to find out optimum story-wise damper distribution pattern using genetic algorithm. The effectiveness of the hybrid damper is investigated by fragility analysis of the structure with and without the dampers. The analysis results show that after seismic retrofit the probability of reaching damage states, especially the complete damage state, of the structure turn out to be significantly reduced.

This study develops a new hybrid passive energy dissipation device for seismic rehabilitation of an existing structure. The device is composed of a friction damper combined with a steel plate with vertical slits as a hysteretic damper. Analytical model is developed for the device, and the capacity of the hybrid device to satisfy a given target performance is determined based on the ASCE/SEI 7-10 process. The effect of the device is verified by nonlinear dynamic analyses using seven earthquake records. The analysis results show that the dissipated inelastic energy is concentrated on the hybrid damper and the maximum interstory drift of the SMRF with damping system satisfies the requirement of the current code.

목 적 : 슬릿 램프용 450nm~500nm 대역 투과필터를 제작하고, 이에 관한 특성 연구를 하였다. 방 법 : 대역 투과필터 설계 시 장파장 투과필터와 단파장 투과필터를 설계한 후 합성하였다. 설계 데이 터를 기반으로 전자 빔 증착 장치를 사용하여 장파장 투과필터와 단파장 투과필터와 슬릿 램프용 450nm~500nm 대역 투과필터를 제작하였다. 제작한 필터의 단면을 보기 위하여 SEM사진을 찍었고, 필터 의 광투과율을 측정하기 위해 분광광도계를 사용하였다. 결 과 : 제작한 단파장 투과필터는 설계치와 비슷하나 파장 490nm 근처와 350nm~400nm에서 차이가 난다. 이는 층 수 가 커짐에 따라 박막의 균일도가 안 좋아져서 필터의 굴절률에 약간 변화를 주어 투과율 스펙트럼의 경사도가 큰 부분에서 차이가 나는 것으로 여겨진다. 제작된 장파장 투과필터는 설계치의 비슷 하며 실험치가 전체적으로 오른쪽으로 약간 이동됨을 알 수 있다. 그러므로 제작한 450nm~500nm 대역 투 과필터는 450nm에서는 장파장 투과필터의 오른쪽 이동으로 인해 설계된 대역 투과필터 안쪽으로 들어가고 500nm에서는 투과율이 약 20% 떨어지는 것을 알 수 있었다. 또한 제작한 필터의 단면은 SEM사진으로부터 단파장 투과필터와 장파장 투과필터의 두께를 알 수 있었다. 결 론 : BK7 유리 한 면에는 단파장 투과필터를 제작하고 다른 한 면에는 장파장 투과필터를 제작하여 450nm~500nm 대역 투과필터를 만들었고, 이 필터를 사용하여 눈의 건조 상태나 콘택트렌즈와 각막 틈새 를 파악할 때 관찰고자 하는 부위의 명도대비를 높이고자 한다.

This report offers an economically reasonable seismic reinforcement to non-seismic mid/low reinforced concrete structures. Installed a slit in between the reinforced concrete frame and masonry infilled wall then inserted twist bar to prevent inversion and attached to the lower/upper beam. Confirmed the seismic reinforcement effect through static loading test. Total of 4 specimens were produced for the test, a masonry infilled wall without seismic reinforcement and with seismic slit or twist bar applied. As a result, applying the seismic slit and twisted bar was economically reasonable and seismic reinforcement effect was confirmed by showing stable failure, increase of maximum strength and yield displacement, increase of accumulated energy dissipation.

목 적: TiO2와 SiO2를 이용한 다층막 코팅으로 슬릿 램프용 450nm~500nm 대역 투과 필터와 500nm~580nm 대역 투과 필터를 설계하였다. 방 법: TiO2와 SiO2의 광학상수를 포락선 방법으로 구한 후, 그 값을 이용하여 450nm~500nm 대역 투 과 필터와 500nm~580nm 대역 투과 필터를 설계하였는데, 두 개의 대역 투과 필터 설계 시 각각의 필터에 서 장파장 투과 필터와 단파장 투과 필터를 설계한 후 합성하였다. 결 과: 450nm~500nm 대역 투과 필터 설계에서 400nm~500nm 단파장 투과 필터는 고 굴절률 층인 TiO2와 저 굴절률 층인 SiO2가 교번으로 30층 구조를 가지고 총 두께는 2273nm이며, 450nm~700nm 장파 장 투과 필터는 TiO2와 SiO2가 교번으로 22층 구조를 가지고 총 두께는 1149nm이다. 또한 500nm~580nm 대역 투과 필터 설계에서 400nm~580nm 단파장 투과 필터는 TiO2와 SiO2가 교번으로 24층 구조를 가지고 총 두께가 2284nm이며, 500nm~700nm 장파장 투과 필터는 TiO2와 SiO2가 교번으로 34층 구조를 가지고 총 두께는 2016nm이다. 결 론: 450nm~500nm 대역 투과 필터와 500nm~580nm 대역 투과 필터를 설계하였는데, 이 두 가지의 필터를 현재 슬릿 램프에 있는 코발트블루 필터와 옐로우 필터 대신 사용하여 플루레신 관찰 시 명도대비를 크게 하려고 한다.

홀로그래피 기술을 응용해서 입체 영화를 만들기 위해 프레넬 방식의 슬릿 홀로그램과 영사시스템에 대해 연구하였다. 슬릿 홀로그램은 한 장의 기록 재료에 영역을 나누어 중복되지 않게 오브젝트를 바꾸어가면서 기록했다. 슬릿 홀로그램은 세로로 긴 직사각형의 모양으로 연속적으로 만들었으며 영화필름과 비교하면 프레임과 같은 역할을 한다. 영사시스템은 레이저 광원, 개구, 슬릿 홀로그램, 볼록렌즈, 프레넬렌즈, 프로젝션 렌즈로 구성했다. 슬릿 홀로그램으로부터 허상을 먼저 재생하고 실상으로 전환하기 위해 슬릿 홀로그램의 앞과 뒤에 개구와 볼록 렌즈를 설치해 3층 구조로 만들었다. 홀로그램으로부터 입체 영상을 재생하는 방법으로는 허상을 먼저 재생한 뒤 볼록 렌즈에 의해 실상으로 전환했다. 슬릿 홀로그램을 기록할 때 오브젝트와 홀로그램까지의 거리를 조정함으로써 대화면의 입체 영상을 재생할 수 있다. 영사시스템에서는 투영 렌즈와 프레낼 렌즈의 초점거리에 변화를 줌으로서 대화면의 영상으로 투영할 수 있었다. 슬릿 홀로그램과 영사시스템에 의해 대형화면으로 스크린에 투영할 수 있었고 입체영화로 실현 가능하다는 것을 확인하였다.

We tested the characteristics of the newly made Long Slit Spectrograph (LSS) of the BOAO which replaced the Medium Dispersion Spectrograph (MDS) in the year of 2003. Performance test results on the spectrogram shift by gravity direction variation, slit illumination function, efficiency and the precision of the radial velocity measurements show the capabilities of the LSS are much improved in every respect comparing with those of the MDS.

We will discuss two-dimmensional spectrophotometry including long-slit spectroscopy and narrow-band imaging. The basic principles, applications, and techniques of observations and data reduction of spectroscopy and spectrophotometry for extended objects are described. This discussion will focus on practical long-slit spectroscopy using a Cassegrain spectrograph attached with 2 or 4m class telescopes and on imaging spectrophotometry using narrow-band interference filter sets. We will discuss scientific applications.

본 연구에서는 비내진상세를 가지는 중⦁저층 R/C 건물의 1층 골조를 제작하여 무보강 실험체에 대한 구조실험을 실시하였다. 실험결과 실험체는 부재각 1.33%에서 전단파괴를 나타내어, 비내진상세를 가지는 R/C 건물의 내진성능에 관한 중요한 자료를 획득하였다. 본 연구에서는 간주형 좌굴방지 강재 슬릿댐퍼 시스템을 개발하였으며 내진보강효과를 검증하기 위하여 구조실험에 선행하여 상기 국내 비내진상세 RC 골조 실험결과를 기반으로 비선형해석을 실시하였다.