Performance improvement using time delays in multivariable controller design

A new controller for linear multivariable ordinary systems is suggested in which distributed delays are included in the feedback loop. A general design approach to obtain this type of controller is suggested. It is shown that the resulting closed-loop system is asymptotically stable under some sufficient conditions. Sufficient conditions are derived under which the disturbance attenuation, the robustness against parameter variations, and the time-delay stability margins are improved by the proposed controller. The state feedback tracking controller and the dual-state observer are obtained by modification of the proposed controller.     

STRESS CONTROLLED FERROELECTRIC (BA0.5Sr0.5)TiO3 THIN FILMS PREPARED ON GD2O3/SRTiO3(001) BY A PULSED LASER DEPOSITION

ABSTRACT

Stress controlled epitaxial ferroelectric Ba_0.5Sr_0.5TiO₃ (BST) films have been deposited on Gd₂O₃/SrTiO₃ by pulsed laser deposition with oxygen background pressure of 200 mTorr at the deposition temperature of 750°C. In order to control the stress in BST films, oxygen pressures for Gd₂O₃ buffer layers have been varied from 0.1 to 100 mTorr, while that of BST films have been fixed at 200 mTorr. It has been found that the lattice parameters of the BST films deposited on Gd₂O₃ were changed. Furthermore, microwave properties of co-planar waveguide (CPW) fabricated on BST films were investigated by a HP 8510C vector network analyzer from 1–20 GHz. Large dielectric tunabilities were observed from the CPW's fabricated on BST films deposited on Gd₂O₃ layers deposited at low and high oxygen pressures, 0.1 and 100 mTorr, respectively.     

Hybrid functional IrO_2-TiO_2 thin film resistor prepared by atomic layer deposition for thermal inkjet printheads

IrO2-TiO2 thin films were prepared by atomic layer deposition using Ir(EtCp)(COD) and titanium isopropoxide (TTIP). The resistivity of IrO2-TiO2 thin films can be easily controlled from 1 500 to 356.7 μΩ·cm by the IrO2 intermixing ratio from 0.55 to 0.78 in the IrO2-TiO2 thin films. The low temperature coefficient of resistance(TCR) values can be obtained by adopting IrO2-TiO2 composite thin films. Moreover, the change in the resistivity of IrO2-TiO2 thin films was below 10% even after O2 annealing process at 600 °C. The step stress test results show that IrO2-TiO2 films have better characteristics than conventional TaN0.8 heater resistor. Therefore, IrO2-TiO2 composite thin films can be used as a heater resistor material in thermal inkjet printhead.     

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.     

1100kV GIS用断路器的设计

介绍了所研制的1 100 kV、50 kA GIS用断路器的技术规范、基本结构及合闸电阻的合理布置;利用商用Maxwell2D,3D软件及专用的程序,对断路器灭弧室的电场分布情况进行了分析,对合闸电阻的热容量进行了计算,并做了相关的试验验证,证明该型断路器的开断性能良好,其所配用的合闸电阻的热容量满足使用要求。     

Synthesis of LiNiO2 cathode by the combustion method

To determine optimum conditions for the synthesis of LiNiO₂ by the combustion method, syntheses were carried out in air and under oxygen at various calcination temperatures and for different times. The electrochemical properties of the prepared samples were then investigated. The optimum conditions are preheating at 400 °C for 30 min in air in the mole ratio of urea to nitrate 3.6 and calcination at 750 °C for 36 h under O₂. The LiNiO₂ synthesized under these conditions had a first discharge capacity of 189 mAh g⁻¹ at 0.1 C-rate and relatively good cycling performance. This sample has a larger value of I ₀₀₃/I ₁₀₄ (smaller cation mixing) and a smaller R-factor (larger hexagonal ordering). Cycling performance was investigated in various voltage ranges. The first discharge capacity increased as the upper limit of the voltage range rose. The first discharge capacity was small but cycling performance was good when the sample was cycled in the voltage range with the lowest upper limit.     

EVALUATION OF PEPPER (CAPSICUM ANNUUM) FOR MANAGEMENT OF DIABETES AND HYPERTENSION

Natural α‐amylase and α‐glucosidase inhibitors from food‐grade plants offer an attractive strategy to control postprandial hyperglycemia for type 2 diabetes management. Concurrently associated macrovascular complication of hypertension can be managed by similar extracts by inhibition of angiotensin I‐converting enzyme (ACE ). In this study, nine types of pepper were investigated for inhibitory activity against said enzymes. Several pepper extracts had high α‐glucosidase inhibitory activity, which was not correlated to total phenolic content and free radical scavenging‐linked antioxidant activity. Select extracts such as Green pepper and Long hot pepper had less or no inhibitory effect on the α‐amylase activity, which indicates the potential for reduced side effects. Among various water extracts, Yellow, Cubanelle and Red pepper had the highest ACE inhibitory activity. Therefore, combinations of pepper could be screened for dietary management of type 2 diabetes, associated hypertension and microvascular complications linked to oxidative dysfunction, and provide the basis for clinical studies.     

Multifunctional Ru-AlN heating resistor films for high efficiency inkjet printhead

Ru-AlN thin films were suggested as a novel multifunctional heating resistor film for non-passivated type thermal inkjet printer devices. Ru-AlN thin films were prepared by plasma-enhanced atomic layer deposition in order to intermix Ru and AlN precisely. When the Ru intermixing ratios were optimized, Ru-AlN films showed a favorable electrical resistivity (from 490.9 to 75.3 μΩcm) and minimized temperature coefficient of resistance (TCR) values (from 335 to 360 ppm/K). Moreover, the Ru-AlN films showed a strong oxidation resistant as compared with commercially used TaN_0.8 films because the prepared Ru-AlN thin films had a typical nanocomposite structure. By applying electrical pulses to the heater device using Ru-AlN thin films for a Joule heating, a reliable operation was also proven.     

Interface characterization of Al/Cu 2-ply composites under various loading conditions

The effects of reduction ratio during roll bonding on the microstructural evolution at interface and subsequent mechanical properties of roll-bonded Al/Cu 2-ply sheets were investigated. The interface microstructures for several Al/Cu 2-ply sheets fabricated under different reduction ratios between 30% and 65% were verified by transmission electron microscopy (TEM). Taking the difference of interface microstructure into consideration, 3-point bending and peel tests were performed for obtaining flexural and bonding strengths for Al/Cu 2-ply sheets. The effect of the quantified areas of metallurgical bonding at interfaces on the bonding strength was also discussed. The results show that both the bonding and flexural strengths for Al/Cu 2-ply sheets are reduced by decreasing the reduction ratio during the roll bonding process, which is strongly correlated with the interface microstructure. This was especially verified by observing the interface delamination from the 3-point bent samples.