Heating curves of solids obtained by a solar furnace

By the use of a heliostat type solar furnace, materials having high melting points can be fused and their freezing points measured with the brightness pyrometer by the specular reflection method in the previous paper.^* The heating curves of a specimen are measured with the brightness pyrometer in the same way, and the melting point of the solid fused with a solar furnace is obtained. The time required to fuse the specimen as a function of irradiance is also calculated from the curve. Experimental data on ZrO₂ and Y₂O₃ are presented.     

The effects of the substrate temperature on sputter-deposited niobium films

The superconducting transition temperatures and the structural properties of Nb films prepared by sputtering have been studied over a deposition temperature range of ?130 to 700°C. Niobium films show a preferred orientation in the <110> direction perpendicular to the substrate surface. The transition temperatures of Nb films deposited onto cryogenic substrates were greatly reduced. A close correspondence between thed spacingd ₁₁₀ and superconductingT _c has been found. TheT _c of Nb films decreases rapidly with increasing spacingd ₁₁₀.     

Application of cross-linked salmon atelocollagen to the scaffold of human periodontal ligament cells

The purpose of this study was to investigate the application of salmon atelocollagen (SAC) to a scaffold. SAC has a low denaturation temperature and needs to be cross-linked before being used as a scaffold. In the present study, SAC was cross-linked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) or dehydrothermal treatment (DHT). The material properties (degree of cross-linking and solubility in phosphate-buffered saline) of the SAC scaffolds cross-linked by EDC (EDC-SAC) and DHT (DHT-SAC) were evaluated. It was found that EDC-SAC had a high degree of cross-linking and high stability compared with DHT-SAC. Human periodontal ligament (HPDL) cells were cultured in the scaffolds for 2 weeks in vitro, and the activities (proliferation rate and alkaline phosphatase [ALP] activity) of HPDL cells cultured in EDC-SAC and DHT-SAC were compared with those cultured in bovine atelocollagen (BAC) scaffolds cross-linked by EDC (EDC-BAC) and DHT (DHT-BAC), respectively. The proliferation rate of HPDL cells cultured in EDC-SAC was equivalent to that in EDC-BAC, and the ALP activity in EDC-SAC was found to be significantly higher than that in EDC-BAC. In the cross-linking by DHT, the cell proliferation rate and the ALP activity in DHT-SAC were lower than those in DHT-BAC. DHT seemed to provide insufficient cross-linking, and DHT-SAC was found to be breakable and contractile, resulting in less cell activity. In contrast, there was no difference in the thermal stability, porous structure, and cell proliferation rate between EDC-SAC and EDC-BAC. In addition, the collagen helix of EDC-SAC was found to be partially denatured, and this structure resulted in the enhancement of ALP activity of HPDL cells compared with that using EDC-BAC. In conclusion, our results indicate that EDC-SAC could be used as a scaffold for in vitro culture.     

Influence of Si/Al ratio on the activity and durability of Pd-ZSM-5 catalysts for nitrogen oxide reduction by methane

The selective reduction of NO by methane on Pd-ZSM-5 catalysts with different Si/Al and Pd loadings was examined in the presence and absence of water vapor. At low Si/Al, NO reduction activity was high and stable, while at higher Si/Al, activity was lower and deactivation was significant. The deactivated samples showed PdO bands in the Raman spectra, which indicated that dispersed Pd cations play a key role in NO reduction. The influence of Si/Al on the stability of dispersed Pd cations suggested the importance of Al site pairs for the stable dispersion of Pd cations.     

Mass spectrometric determination of waxy corn (Maize) starch in glutinous (waxy) rice cake by use of 13C/12C ratio

Glutinous (waxy) rice cake is a popular New Year food in Japan. Economic incentives exist for rice cake producers to adulterate the products and mislabel them. Stable carbon isotope ratios (¹³C/¹²C) in rice cake products were determined by mass spectrometry to detect such adulteration. Since the ¹³C/¹²C ratios in rice (δ¹³C value of ca - 25 ppt, parts per thousand are different from those of corn (maize) starch (ca ?9 ppt), the presence of added waxy corn (maize) starch in rice cake could be detected.     

A three-axis vibration isolation system using modified zero-power controller with parallel mechanism technique

This paper proposes a module-type three-degree-of-freedom vibration isolation system using modified zero-power control. Three vibration isolation modules are connected together using parallel mechanism to control 3-DOF motions. Each module consists of a common base, an individual middle mass and a common isolation table. The base to the middle mass is suspended by positive springs generated by active and passive system, and the middle mass and the isolation table is connected by negative spring realized by active-type modified zero-power control. The developed system could realize zero-compliance to direct disturbances as well as good ground vibration isolation. Furthermore, the isolation table is supported by a weight support mechanism for supporting heavy payloads. In the previous research, a concentrated middle mass with redundant actuators, in the vertical and horizontal directions, were used. Therefore, a vibration isolation system is proposed in this work using modular concept to overcome those drawbacks. Each module is controlled separately by decentralized control technique, and three modules can be used for three-degree-of-freedom of motion control. Therefore, no redundancy of actuator is occurred. Moreover, an improved zero-power controller is presented that can adjust negative stiffness instead of conventional zero-power controller. The results obtained from analytical and experimental studies show that the modular technique is reliable and efficient approach to vibration control, and represents a suitable alternative to the conventional active vibration isolation systems.