Optical diffraction gratings embedded in BK-7 glass by low-density plasma formation using femtosecond laser

The optical embedded diffraction gratings with the internal refractive index modification in BK-7 glass plates were demonstrated using low-density plasma formation excited by a high-intensity femtosecond (130 fs) Ti: sapphire laser (λp=790 nm). The refractive index modifications with diameters ranging from 400 nm to 4 μm were photoinduced after plasma formation occurred upon irradiation with peak intensities of more than 1×1013 W/cm2. The graded refractive index profile was fabricated to be a symmetric around the center of the point at which low-density plasma occurred. The maximum refractive index change (Δn) was estimated to be 1.5×10-2. Several optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.     

Creep and tensile properties of press molding joined GMT-sheets

GMT-sheet is used in automobile bumper with high rigidity and strength, and its joining strength is influenced by lap length, one of the joined molding conditions. Fracture strength was calculated by dividing fracture load with cross-sectional area. Total five repeated measurements were made to obtain the average value. Tensile test was conducted at room temperature for 10 specimens. In addition, the effect of compression ratio on creep and tensile performance during lap joined molding was discussed. With increasing lap length, the lap joining efficiency of GMT-sheet was increased. However, higher compression ratio reduced the joining efficiency. Creep test on GMT-sheet showed abrupt fracture without tertiary creep. This can be explained by the weak thermal resistance of the resin. If GMT-sheet was exposed to high temperature for a long time, it was easily failed by external force.     

Effect of CaO composition on oxidation and burning behaviors of AM50 Mg alloy

Oxidation and burning behaviors were studied for CaO added AM50 Mg composites which were manufactured by conventional melting and casting processes without SF₆ protective gas. CaO added AM50 Mg composites show the stable oxidation resistance, while AM50 Mg alloys show the poor oxidation resistance. The effects of CaO addition on the burning resistance under ambient, nitrogen and dry air atmospheres were examined for CaO added AM50 Mg composites. With increasing CaO addition, the burning temperature increases under ambient, nitrogen and dry air atmospheres. The burning temperatures of small test specimen under all conditions greatly increase even by 0.3% CaO (mass fraction) addition into AM50 Mg alloys.     

Effect of carbon on microstructure of CrAlCxN1-x coatings by hybrid coating system

A systematic investigation of the microstructure of CrAlC_xN_1-x coatings as a function of carbon contents was conducted. Quaternary CrAlC_xN_1-x coatings were deposited on Si wafers by a hybrid coating system combining an arc-ion plating technique and a DC reactive magnetron sputtering technique using Cr and Al targets in the Ar/N₂/CH₄ gaseous mixture. The effect of carbon content on microstructure of CrAlC_xN_1-x coatings was investigated with instrumental analyses of X-ray diffraction, X-ray photoelectron, and high-resolution transmission electron microscopy. The results show that the carbon content of CrAlC_xN_1-x coatings linearly increases with increasing CH₄/(CH₄/N₂) gas flow rate ratio. The surface roughness of the CrAlC_xN_1-x coating layer decreases with the increase of carbon content.     

Metrics for Quantifying the Similarities and Differences between IFC Files

Recently, several papers reported problems in data exchange using industry foundation classes (IFC). However, most comparisons were made based on a visual check, a manual count, and observation of properties that were selectively chosen. This study proposes a set of metrics for quantifying the similarities and differences between IFC files. The proposed metrics include the similarity rate, the matching rate, the globally unique identifier (GUID) preservation rate, the missing rate, and the addition rate. A long-term goal of this study is to develop a set of metrics for quantifying the information exchange rate between two IFC files. Automated identification of modified information versus newly generated information is an unsolved challenge. The proposed metrics were used in analyzing 88 IFC files generated from different systems to demonstrate the potential use of the proposed metrics.     

Role of O2/Ar mixing ratio on the performances of IZO thin film transistors fabricated using a two-step deposition process

In this study, a simple method of fabricating a thin-film transistor (TFT) with a double-layered channel using indium–zinc-oxide (IZO) films was proposed. Two IZO films used as channel layers were consecutively deposited via sputtering without stopping the vacuum and only by changing the volumetric fraction of the additive O₂ gas during the deposition. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis showed a large difference in the depth profiles of the InO^? and InO₂^? ions between the two IZO layers. Compared to the conventional single-IZO-channel TFT, the double-IZO-channel TFT that was fabricated using the proposed two-step deposition method showed greatly improved electrical characteristics: the on/off-state current ratio was increased from 1.30 × 10⁵ to 1.03 × 10⁶, and the field effect mobility was enhanced from 1.2 to 9.3 cm²/Vs.     

Studies on the heating capacity control of a multi-type heat pump system applying a multi-input multi-output (MIMO) method

This paper describes a method to control capacity of a multi-type heat pump system. Because indoor units are interconnected, alteration of the heating or cooling setting of one indoor unit can influence the performance of the other indoor units. Proportional-integral (PI) controllers were used to assess system performance, and the PI controllers’ gain values were optimized by using a genetic algorithm. A system model was established following a system identification optimization process, and a pseudo random binary sequence was selected as the system identification input signal. A multi-input multi-output (MIMO) controller was more effective in reducing such cross-coupling effects than a single-input single-output (SISO) controller. The temperature at the secondary fluid outlet in the condenser and the saturation pressure at the evaporator were selected as the control variables in the MIMO controller. The experimental results showed that an optimized MIMO controller could reduce overshoot by up to 40% compared with the results using a SISO controller.     

Molecular dynamics study on nanotube-resonators with mass migration applicable to both frequency-tuner and data-storage-media

We investigated the cantilevered carbon-nanotube-resonator including electromigratively movable nanoparticle via classical molecular dynamics simulations and continuum model. The change of the effective mass value, which was closely correlated with the position change of the encapsulated nanoparticle, could be regressed by a power function, the resonance frequency of the carbon-nanotube-resonator could be tuned by controlling the nanoparticle’s position, and the possible frequency-shift-ranges then reached 18–85%. The suggested device could be served as a data-storage-media for electromechanical nonvolatile-memory as well as a frequency-tuner.