• Steel and Composite Structures
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• v.13 no.1
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• pp.15-33
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• 2012

For an axially loaded box-shaped member, the width-to-thickness ratio of the plate elements preferably should not be greater than 40 for Q235 steel grades in accordance with the Chinese code GB50017-2003. However, in practical engineering the plate width-to-thickness ratio is up to 120, much more than the limiting value. In this paper, a 3D nonlinear finite element model is developed that accounts for both geometrical imperfections and residual stresses and the ultimate capacity of welded built-up box columns, with larger width-to-thickness ratios of 60, 70, 80, and 100, is simulated. At the same time, the interaction buckling strength of these members is determined using the effective width method recommended in the Chinese code GB50018-2002, Eurocode 3 EN1993-1 and American standard ANSI/AISC 360-10 and the direct strength method developed in recent years. The studies show that the finite element model proposed can simulate the behavior of nonlinear buckling of axially loaded box-shaped members very well. The width-to-thickness ratio of the plate elements in welded box section columns can be enlarged up to 100 for Q235 steel grades. Good agreements are observed between the results obtained from the FEM and direct strength method. The modified direct strength method provides a better estimation of the column strength compared to the direct strength method over the full range of plate width-to-thickness ratio. The Chinese code and Eurocode 3 are overly conservative prediction of column capacity while the American standard provides a better prediction and is slightly conservative for b/t = 60. Therefore, it is suggested that the modified direct strength method should be adopted when revising the Chinese code.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1259-1265
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• 2020

A beta ray scanner was proposed for in-situ discrimination of beta and gamma ray radioactivity. This scanner is based on the principle that gamma and beta rays experience different changes in detection efficiency in scintillators with different geometries, especially with regard to the scintillator thickness. The ratios of the counting rates of gamma rays (R_gamma), beta rays (R_beta), and sample measurements (R_total) in a thick scintillator to those in a thin one are reported. The parameter X_thick, which represents the counting rate contributed by beta rays to the total counting rate in the thick scintillator, was derived as a function of those ratios. The values of R_gamma and R_beta for ⁶⁰Co and ⁹⁰Sr sources were estimated as 3.2 ± 0.057 and 0.99 ± 0.0049, respectively. The estimated beta ray contributions had relative standard deviations of 2.05-4.96%. The estimated range of the beta rays emitted from ⁹⁰Sr was 19 mm as per the Monte Carlo N-Particle simulation, and this value was experimentally verified. Homogeneous and surface contaminations of ⁶⁰Co and ⁹⁰Sr-⁹⁰Y were simulated for application of the proposed method. The counting rate contributed by the beta rays was derived and found to be proportional to the concentration of ⁹⁰Sr-⁹⁰Y contamination.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.825-831
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• 2010

In this study is stress behavior of steel support structure is to identify basic research. Steel stress due to load step to determine the behavior of steel using strain gauge steel loading test was performed. Numerical analysis and steel loading test using strain gauge on the actual steel stress behavior was analyzed. First, when tensile loading 3.5tonf load side of the plastic behavior appeared. Elastic model, using numerical analysis and comparison of results, the actual value is saved and you can see some difference. This repeated loading tests on steel can be seen from the results of the stress behavior of the steel rather than the elastic behavior of elastic-plastic behavior is because you can see. In addition, the upper and lower steel stress in compression and tension behavior represents the behavior was similar, but different. Steel loading test results, Y-axis get a compression if X-axis is tension. The future based on this study, the stress sensitivity curve of magnetic anisotropy sensor for non-destructive stress measurement technique for the study will be performed. And the behavior of plastic zone and residual stress to determine the numerical analysis using non-elastic model is needed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.137-143
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• 2010

This paper deals with the performance comparison of self adaptive equalizer by the weighting factor of MCMA cost function for the compensate the amplitude and phase distortion which occurs in the communication channel. The MCMA is improves the cost function of present CMA at the output of equalizer for the minimize of error function in the amplitude and phase, the value of weighting factor is used at this time. When the comparison of equalizer performance, we classified to initial state and steady state, then it represents the convergence time and convergence speed and steady state operation of equalizer to the predetermined level, it is determined by the weighting factor. We confirm to the different result to this 2 state by weighting factor values using computer simulation. By using the result of this paper, if we appropriately choose the weighting factor values in the environment of communication channel, it is expected that the high quality digital transmission is possible.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.9
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• pp.1545-1550
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• 2006

In this paper, we propose a method for applying the CLEAN algorithm to an minimum variance distortionless response(MVDR) to estimate the location of multiple targets distributed in the ocean. The CLEAN algorithm is easy to implement in a linear processor, yet not in a nonlinear processor. In the proposed method, the CSDM of a Dirty map is separated into the CSDM of a Clean beam and the CSDM of the Residual, then an individual ambiguity surface(AMS) is generated. As such, the CLEAN algorithm can be applied to an MVDR, a nonlinear processor. To solve the ill-conditioned problem related to the matrix inversiion by an MVDR when using the CLEAN algorithm, Singular value decomposition(SVD) is carried out, then the reciprocal of small eigenvalues is replaced with zero. Experimental results show that the proposed method improves the performance of an MVDR.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.6
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• pp.639-643
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• 2008

STATEMENT OF PROBLEM: The degree of conversion may influence the ultimate mechanical and physical properties of provisional crown and fixed partial denture materials. The high levels of the unreacted residual monomer may cause deleterious effect on the properties. PURPOSE: The purpose of this study was to measure the degree of conversion of bis-acrylic based provisional crown and fixed partial denture materials by using an infrared spectroscopic method. MATERIAL AND METHODS: Chemically activated three bis-acrylic based provisional crown and fixed partial denture materials, LuxaTemp [DMG, Hamburg, Germany], fast set TemPhase [Kerr, Orange, CA, USA] and Protemp 3 Garant [3M-ESPE, St Paul, MN, USA], were investigated by Fourier transform infrared spectrometry (FTIR). The FTIR spectra of the materials tested were immediately obtained after mixing. The specimens were stored under dry conditions and at $23^{\circ}C$ for 24 hours, and then the spectra of the materials were also obtained. The degree of conversion (%) was calculated from the spectrum of the absorbance between the aliphatic double bond at 1637 $cm^{-1}$ and the aromatic double bond at 1608 $cm^{-1}$ using the baseline method. The data were statistically analyzed using one-way ANOVA and the multiple comparison Scheffe test at the significance level of 0.05. RESULTS: The mean value and standard deviation of the degree of conversion were 52.5 % ${\pm}$ 1.1 %, 50.3 % ${\pm}$ 0.8 %, and 42.3 % ${\pm}$ 4.9 % for LuxaTemp, Protemp 3 Garant and fast set TemPhase, respectively. There was no significant difference between LuxaTemp and Protemp 3 Garant, whereas there was a statistically difference between Protemp 3 Garant and fast set TemPhase, and LuxaTemp and fast set TemPhase (P < .05). CONCLUSION: The degree of conversion of fast set TemPhase was significantly lower than those of the others. The degree of conversion may be correlated with the rate of polymerization.

• Journal of Information Technology Application
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• v.3 no.2
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• pp.67-82
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• 2001

The ILOF project addresses the needs of logistics industrial organizations to reduce information processing time, improve added and residual value of information and reduce processing and transportation costs. It deals with the information supply chain information systems shared by vertical partner as important entity, whose performance and optimization very significantly affects the efficiency and performance of logistics industries. This paper deals with logistics information exchange systems based on supply chain management, focusing on sharing database and processes between partners such as shipper, logistics broker, transportation company, shipping company etc., for smoothing the information flow, enhancing consumer service and reducing communication fee and labour costs. The significance of contribution of this research is the provision of a model for logistics information exchange including entity relationship diagram, data flow diagram and functions which is able to facilitate the formulation of a customer driven supply chain information network, there by enhancing the competitive edge of companies in logistics industries on local and global basis.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.27-32
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• 1988

The almost similar degumming effect was obtained by using oxalic acid instead of phosphoric acid, which also improves waste-water treatment. At this point, solution of Phosphoric, Acetic, Citric, Oxalic, and Nitric acid were used for degumming of rapeseed and soybean oil. Compared with Phosphoric(PA) and Oxalic acid(OA) were showed a simillar degumming effect in these vegetable oils. In rapeseed oil of 85% PA treating group and 5,10% OA fretting group, residual soap and phosphorus content in neutralized oil, color in bleached oil, and peroxide value and fatty acid content in deodrized oil were showed to simillar result. Soybean oil as well as rapeseed oil were showed to similar result. As a result, we could comfirmed substitutive possibility, which change PA into OA as a degumming agent. In the other hand, waste waters were obtained from 55% PA treating group and 10% OA treating group. Analytical result for this waste waters has showed a wide difference, especially in the BOD and COD. The amount of treating agents and time required in the precipitation seperation and chemical treatment each 3 and 1.7 times, which is PA treating group than OA treating group. We have investigated both the simillar degumming effect by OA solution and an alternative the pollution program means of a chemical treatment process is not possible.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.1-8
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• 1994

A five mirror system with a reduction magnification(M=+1/5) is designed for DUV optical lithography. First, for spherical mirror systems, the numerical solutions of all zero 3rd order aberrations are derived and the 3-dimensional shape of the solution-domain is obtained. In these solutions, we select solutions which have as less residual aberrations and smaller central obscurration as possible and the aspherization is carried out to the last two spherical mirrors to obtain a system that has as higher NA as possible. Finally we obtain the system of which NA is 0.45, the central obscuration is about 25% and the resolution is about 650 cycles/mm at the 50% MTF value criterion and the depth of focus of 0.8${\mu}m$ for the nearly incoherent illumination (${\sigma}$=1.0) and the wavelength of 0.193${\mu}m$ (ArF excimer laser line).

• Journal of Power System Engineering
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• v.20 no.6
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• pp.40-45
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• 2016

The manufacturing process of large scaled Al 7050 alloy is difficult for the occurrence of solidification crack during casting. The aims of this study are the evaluations of microstructure and mechanical properties of extruded Al 7050 billet and ring forged one with large scale. Large scaled Al 7050 billet was casted by direct-chill casting process. The extruded and ring forged specimens were prepared from the casted ingot after residual stress relief and homogenization heat treatment, respectively. Microstructures, hardness and tensile test of the surface, middle and center part of each specimen were performed at room temperature. Sheared and elongated type grains were observed at the edge parts of surface and center area and its aspect ratios of grains were low and similar as 0.21 while that of middle area was closed to 0.92 value in ring forged Al 7050 alloy. The mechanical properties of extruded Al 7050 alloy were superior than those of ring forged one. The hardness values of surface and center part were slightly higher than that of middle part in ring forged Al 7050 alloy.