• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.161-168
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• 2001

The use of composite members to improve the compressive strength of steel structure is a common practice these days and its efficiency has already been proved by several researches and experiments. The result of concrete filled circular tubular(CFCT) stub column tests is introduced in this paper. The main parameter of this test is the ratio of diameter to thickness of circular hollow section. From the test results, the effect of concrete filled in steel tube on the ultimate strength, the deformation capacity and initial stiffness are discussed. The purpose of this paper is to investigate the effect of various parameters and evaluate the compressive strength of confined concrete. It would contribute to a better understanding of CFT structure, further laboratory experimentations are needed for better accurate estimation on its effect.

• 대한전자공학회논문지
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• 제4권4호
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• pp.2-12
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• 1967

MOS 전계효과 transistor를 이용하여 직류착동증폭기를 설계하여 A 정도의 극미소직류전류를 측정하는 장치에 관한 연구이다. 등가회로를 이용하여 전압이득과 동상전압변별비를 주는 식을 유도하였으며 유효등가 source 저항을 대단히 높이기 위한 정전류원회로의 실현을 위한 해석을 하였다. 전압이득은 6.6, 상온에서의 drift는 하루에 1.5mv 정도이고 동상전압변별비는 최고 84db 이었다. 이것은 MOS transistor의 대단히 높은 입력저항의 특징을 살려 전잡상등에서 나오는 극미소직류전류의 측정을 간단하게 할 수 있게 하는 것이다.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.377-384
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• 2020

Banking is very regulated by the government and even has to follow regulations issued by the Basel Committee on Banking Supervision, which regulates banking in the world. According to Basel III, banks must provide capital reserves called capital buffers. The purpose of this study is to examine the factors that determine capital buffer. Factors thought to affect the capital buffer studied consisted of profitability (ROA), credit risk (NPL), liquidity risk (LDR), capital adequacy in the previous period (CARt-1), management risk (NIM), and ratio of operating risk (OER). The population in this study is conventional banks listed on the Indonesia Stock Exchange, as many as 42 banks, with a sample of 40 banks taken by purposive sampling method with an observation period of four years with quarterly data (2016-2019). To test the hypotheses, regression panel data is used. After being tested, it turns out that the fixed effect model is better than the common effect and random effect. The results of the study with fixed effect models show that ROA, NPL, and OER significantly and negatively affect capital buffer. CAR_t-1 has a positive and significant effect on capital buffer, while LDR and NIM do not affect capital buffer.

• 한국염색가공학회지
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• 제20권1호
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• pp.28-35
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• 2008

Texturing is the process of including a characteristic of a natural fiber in a synthetic fiber. The most common method of it the false twist texturing. Nylon textured yarn is primarily manufactured by the disk type. The major process parameters or the disk type false twist machine ratio, disk/yarn, and heater temperature. This study therefore investigated the effects of false twist texturing, especially speed and draw ratio, on the physical properties of nylon textured yarn. The increase of speed was proportional to the increase of unwinding tension, which could reduce the production efficiency by elevating the tension affecting to fiber during the process. In addition, the increase of speed was inversely proportional to the increase of crimp rigidity of nylon textured yarn. Draw ratio was proportionally increased with the increase of tenacity and the reductions of fineness and elongation, showing the influence or draw ratio to the ultimate physical properties of textured yarn.

• 한국양식학회지
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• 제13권1호
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• pp.1-7
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• 2000

The effect of various dietary protein levels on growth and body composition of young common carp raised from 56 g to 170 g in recirculating system was investigated for 15 weeks when they were fed to visual satiety three times daily. Five experiemtal diets were formulated to contain 40, 35, 30, 25 and 21% protein levels and 3.56, 3.59. 3.63, 3.66 and 3.69 kcal/g diet GE levels respectively. Mean survival rates of the fish fed the 40, 35, 30 and 25% protein diets were not different but sig-nificantly higher than that of the fish fed the 40, 35, 30 and 25% protein diets were not different but sig-nificantly higher than that of o the fish fed the 21% protein diet(P<0.05) Weight gain (g/tank) of common carp fed the 30% protein diet was the best. However weight gain of the fish fed the 25, 30, 35 and 40% protein diets were not different but significantly better than that of the fish fed the 21% protein diet. Feed efficiency ratio of the 21% protein diet was significantly lower (P<0.05) than for other groups of diets which were not different among them. Protein efficiency ratio for the 21% protein diet was significantly lower (P<0.05) than for other groups of diets which were not different among them(P>0.05) Dietary protein level had no effect on hemoglobin content in the fish(P>0.05) Crude protein contents of whole body of the fish fed the 35 and 40% protein diets were significantly higher than that of the fish fed the 21$$\mid$% or 25% protein diet(P<0.05) Body crude lipid contents of the fish fed the 21 and 25% protein diets were significantly higher than that of the fish fed the 30% or 35% protein diet. Crude ash contents of the fish fed the 35 and 40% protein diets were significantly higher than that of the fish fed the 21% or 25% protein diet(P<0.05) Moisture content of the fish fed the 35% protein diet was significantly higher than that of the fish fed the 21% protein diet(P<0.05) In considering growth performance of common carp and efficiency of diet dietary protein level could be lowered up to 25% without the reduction of young common carp production in recirculating system.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.37-43
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• 2003

The objective of this work is to investigate the effect of swirl, injection pressure and pilot injection on D.I. diesel combustion by using a transparent engine system. The test engine is equipped with common rail injection system to obtain high pressure and to control injection timing and duration. In this study, the combustion analysis and steady flow test were conducted to estimate the heat release rate from in-cylinder pressure. Soot distribution in diffusion flame according to swirl ratio, injection pressure and pilot injection was investigated by using LII technique. As the results, high injection pressure was found to shorten ignition delay as well as enhance peak pressure and heat release rate was greatly affected by injection timing and pilot injection. In addition, the results showed that the period of soot formation corresponded to the diffusion flame.

• 한국자동차공학회논문집
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• 제17권2호
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• pp.171-179
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• 2009

An object of this study is to confirm application characteristics of the vortex tube apparatus for substitution of the intercooler in a common-rail diesel engine. The turbo pressure, the intake air mass flow rate and the charging air cooling ratio of the intercooler were measured in an experimental engine. The vortex tube apparatus was made after confirmation of the geometric phenomena in fundamental experiments. The vortex tube designed with fundamental data was applied to a conventional common-rail diesel engine instead of the intercooler. Its application characteristics, engine performances and emissions were investigated. From this experimental results, we suggested the vortex tube can be applied to a conventional common-rail diesel engine throughout extra complement. We can also expect the higher cooling effect, if we consider the application of the vortex tube in supercharging diesel engine without the intercooler.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
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• pp.146-151
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• 2004

The characteristics of combustion and emission of biodiesel fuel were investigated in a single cylinder DI diesel engine equipped with a common rail injection system. For investigating the effect of bio diesels, the experiments were conducted at various mixing ratio and engine operation conditions. Experimental results show that combustion pressure increased with the increase of mixing ratio and injection pressure. The HC and CO emissions are decreased and NOx emission is increased as the mixing ratio of biodiesels increases at 100MPa injection pressure. However the results of the emissions are shown the contrary to the results at 50MPa of injection pressure due to larger droplets of biodiesel sprays.

• 한국전자파학회논문지
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• 제16권11호
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• pp.1147-1154
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• 2005

본 논문에서는 OFDM(Orthogonal Frequency Division Multiplexing) 시스템에서 다중 케리 어(multi carrier) 변조에 의해 크게 발생되는 PAPR(Peak to Average Power Ratio)을 저감하기 위한 방법으로 WHT(Walsh Hadamard Transform)를 이용한 PAPR 저감 기법들을 제안한다. 제안하는 방법은 기본적으로 WHT를 기존의 PAPR 저감 기법들과 혼합하여 추가적인 대역 손실 및 큰 복잡도의 증가 없이 추가적인 PAPR저감 성능을 나타내도록 하는 방법으로, 본 논문에서는 SLM(Selective Mapping) 및 DSI(Dummy Sequence Insertion) 방법을 WHT와 결합한 방법을 제시하며, 시뮬레이션 결과로부터, WHT를 이용한 PAPR 저감 기법들이 기존의 PAPR 저감 기법보다 항상 약 1 dB 가량의 더 나은 PAPR 저감 효과를 나타냄을 확인하였다. 또한 제안된 방법은 PAPR저감뿐만 아니라 주파수 다이버시티(diversity) 효과를 얻을 수 있기 때문에 비선형 증폭기에 의한 비선형 왜곡뿐만 아니라 다중 경로 페이딩(multipath lading)이 심하게 일어나는 무선 채널 환경에서 보다 안정된 데이터 전송을 가능케 할 것으로 기대된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.106-110
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• 1995

Chloride ion is considered one of the most common culprits in the corrosion of steel in concrete. It breaks down the passive film and allows the steel to corrode actively at a high rate. The main objective of this study is to determine the critical chloride ion concentrations in the pore solutions and chloride binding effect of cement pastes made with and without fly ash. Cement pastes with water-ratio of 0.5 allowed to hydrate in sealed containers for 28 days and to express poresolution. T도 expressed pore fluids were analyzed for chloride and hydroxyl ion concentrations. It was found that the replaced cement with fly ash have little effect on Chloride binding capacity ratio.