: All-ceramic crowns are the most esthetic, because they transmit light similarly to natural teeth.However, because of the translucency of all-ceramic crowns, the color of the abutment tooth can affect the color of the final crowns.The aim of this study was to investigate the influences of the color of the abutment tooth on all-ceramic crowns.Ceramic disc specimens (In-Ceram, Hi-Ceram, Optec and G-cera II), metal disc abutment specimens (type IV gold and gold-silver-palladium alloy) and porcelain disc abutment specimens (A 1 and A 4) were used for the study. The color of ceramic specimens was measured with a small area colorimeter by translucent and reflectant methods and evaluated by the CIE L*a*b* color system. The results were as follows :1. All ceramic systems with an aluminous core have low translucency, so the color of the abutment tooth does not have to be considered.2 . All ceramic systems with masking porcelain have high reflectance, so the light reflectance have to be considered. 3. All ceramic systems with high translucency have to be considered due to the effect of the color of the abutment tooth.
Received Sept . 5 2000 ; Revision ac ¢ epted Aug . 10 厂 20D1 ; Code No . 862 苺 覇驪 鑼飜 Recently , an increasing number of yolumetric studies of the human brain have been reported , using three − dimensiona 亅magnetic resonance imaging (3D −MRI) . To our knowledge , however , there are few investiga 一
Weld residual stress of a small bore pipe was evaluated using three-dimensional thermal elasto-plastic analysis, which was based on the finite element method (FEM), taking into consideration the effect of a moving heat source during the butt-weld process. A moving heat source during the weld process complicates analysis process due to the necessity of considering the set welding conditions at each time step and this increases computation time. Therefore, there are remarkably few studies on the effect of a moving heat source during the weld process on the analytical results of weld residual stress for small bore pipes. We used this analysis to find the effect of the welding start/end on weld residual stress. Weld residual stress is not a circumferentially uniform state. Increased tensile and compressive residual stress occurred near the end position of the final welding pass. In addition, an accelerated stress corrosion cracking (SCC) test was carried out using a boiling 42% magnesium chloride (MgCl2) solution. In particular, butt-weld joints of low-carbon austenitic stainless steel (Type 316L) pipe, which is often used in boiling water reactors (BWRs), were examined. Comparison between three-dimensional thermal elasto-plastic analysis and accelerated SCC testing showed the tensile stress zone indicated by analysis agreed well with SCC occurrence indicated by examination.
As a promising tool for By measuring the increase of the greenhouse gas which assumes carbon dioxide (following CO₂ ) a representative, we propose to adapt the IC sensing tag. However, the method to grasp the CO₂ density in the urban area is difficult, and it is convenient to utilize the data such as the traffic density in a model type when we evaluate the variation of CO₂ volume in the objective area in many cases. In this study, therefore, we attempt to build a system for observing CO₂ density in Ibaraki prefecture in cooperation with the local government. Anyone can see and utilize information through a network if this would be successful. We aim at getting the data in order for us to contribute to the city formation with less environmental impact and reduction of CO₂ in the urban area, by incorporating the data on climate change and land use improvement.キーワード: CO₂,グリッド,センサ,大気,センシングネットワーク
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