The low temperature polysilicon (LTPS) thin film MOS Schottky diode on glass substrate for low cost and high performance CO sensing applications

The Au/SnO₂/n-LTPS MOS Schottky diode prepared on a glass substrate for carbon monoxide (CO) sensing applications is studied. The n-LTPS (n-type low temperature polysilicon) is prepared by excimer laser annealing and PH₃ plasma treatment of an amorphous Si thin film on glass substrate. The developed Schottky diode exhibits a high relative response ratio of ∼546% to 100 ppm CO ambient under condition of 200 °C and −3 V bias. The response ratio is better than the reported SnO₂ based resistive type CO sensors of 100% and 37%, respectively on poly-alumina and glass substrates or comparable to 390% of Pt-AlGaN/GaN Schottky diode CO sensor. Thus, the Au/SnO₂/n-LTPS Schottky diode has the potential to develop a low cost high performance CO sensor.     

Nanoindentation and nanomachining characteristics of gold and platinum thin films

Molecular dynamics (MD) simulation and an experimental method were carried out to study the effects of applied load, hold time, and temperature on nanoscratching and nanoindentation of gold and platinum thin films. The simulated results showed that the wear depth of gold decreased as the scratching velocity was increased and the temperature was decreased. The results also indicated that when the simulated nanoindentation of gold film hold time was increased, the plastic indentation depth and the plastic energy both increased. In addition, the experimental results showed that the groove depth for gold films was larger than that of platinum films under the same machining load. The wear depth and the surface roughness of platinum films were larger than those of gold films under the same lateral machining feed. Furthermore, the simulated plastic energy of gold films was compared during nanoindentation test.     

FT-IR Microspectrometry Reveals the Variation of Membrane Polarizability due to Epigenomic Effect on Epithelial Ovarian Cancer

Ovarian cancer, as well as other cancers, is primarily caused by methylation at cytosines in CpG islands, but the current marker for ovarian cancer is low in sensitivity and failed in early-stage detection. Fourier transform infrared (FT-IR) spectroscopy is powerful in analysis of functional groups within molecules, and infrared microscopy illustrates the location of specific groups within single cells. In this study, we applied HPLC and FT-IR microspectrometry to study normal epithelial ovarian cell line immortalized ovarian surface epithelium (IOSE), two epithelial ovarian cell lines (A2780 and CP70) with distinct properties, and the effect of a cancer drug 5-aza-2''-deoxycytidine (5-aza) without labeling. Our results reveal that inhibition of methylation on cytosine with 5-aza initiates the protein expression. Furthermore, paraffin-adsorption kinetic study allows us to distinguish hypermethylated and hypomethyated cells, and this assay can be a potential diagnosis method for cancer screening.     

APPLICATIONS OF FOURIER SERIES TECHNIQUE TO TRANSIENT HEAT TRANSFER PROBLEM

For transient heat transfer problem with uniform initial temperature, the Laplace transformation method is considerably powerful. However, it is very difficult and complicated to solve the inverse transform of the subsidiary equation of the given differential equation. The technique of Fourier series can be used in order to obtain the inverse transform. The analysis of transient heat transfer problem of two-dimensional and one-dimensional straight fins is considered here to testify the merit of this method.     

A prediction of the friction factor for the forging process

A method is proposed to find the friction factor of the die/workpiece interface for the forging process without the need for measurement of the shape changes of the workpiece. This methodology is mainly based on the concept of the inverse analysis and requires only the defining of the problem inversely, without the need for mathematically inverting the problem. Comparison of the results of the proposed method with those obtained by the conventional calibration curve method shows good agreement between them, indicating that the proposed method is quite acceptable. Using the proposed model to predict the influence of die velocity on the friction factor shows that the friction factor decreases when the die velocity is increased, further confirming the validity of the proposed approach.     

Surface Roughness Effects in Journal Bearings with Non-Newtonian Lubricants

The static performance of finite journal bearings lubricated with non-Newtonian power law fluids is analyzed by using a control volume method with an Elrod algorithm to solve the average Reynolds equation and determine the cavitation region accurately. The results show that the flow behavior index of power law fluids has an insignificant affect on the load ratios, side flow ratios and cavitation regions, while it significantly affects load capacities and side flow rates. Furthermore, the effects of film thickness ratios, pressure flow factors, shear flow factors, slenderness ratios, eccentricities and inlet pressures on the variations of cavitation regions are also discussed.     

DEFORMATION CONTROL OF LAMINATED COMPOSITE PLATES CONTAINING PIEZOELECTRIC LAYERS UNDER THERMAL LOADING

A composite plate containing piezoceramics on both the upper and bottom surfaces is considered. Based on the piezoelectricity with consideration for the coupling between the strain field and the electric field, a finite element formulation is developed. An eight-node three-dimensional brick element is used, and three-dimensional incompatible modes are introduced to take into account the bending behavior of the structure. The response of the structure and the sensor electrical outputs subjected to thermal loading as well as the required voltage that should be applied to reduce the deflection resulting from thermal loading are analyzed. In addition, this study also analyzes the effect of coupling between the strain field and the electrical field. It shows that the coupling effect may not be negligible; the larger the piezoelectric constant, or the thinner the main structure, the larger the coupling effect will be.     

Least squares subspace projection approach to mixed pixelclassification for hyperspectral images

An orthogonal subspace projection (OSP) method using linear mixture modeling was recently explored in hyperspectral image classification and has shown promise in signature detection, discrimination, and classification. In this paper, the OSP is revisited and extended by three unconstrained least squares subspace projection approaches, called signature space OSP, target signature space OSP, and oblique subspace projection, where the abundances of spectral signatures are not known a priori but need to be estimated, a situation to which the OSP cannot be directly applied. The proposed three subspace projection methods can be used not only to estimate signature abundance, but also to classify a target signature at subpixel scale so as to achieve subpixel detection. As a result, they can be viewed as a posteriori OSP as opposed to OSP, which can be thought of as a priori OSP. In order to evaluate these three approaches, their associated least squares estimation errors are cast as a signal detection problem ill the framework of the Neyman-Pearson detection theory so that the effectiveness of their generated classifiers can be measured by receiver operating characteristics (ROC) analysis. All results are demonstrated by computer simulations and Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data     

A low cost n-SiCN/p-SiCN homojunction for high temperature and high gain ultraviolet detecting applications

A novel n-SiCN/p-SiCN homojunction was developed on Si substrate for low cost and high temperature ultraviolet (UV) detecting applications. The current ratio of the junction under −5 V bias, with and without irradiation of 254 nm UV light are 1940 and 96.3, at room temperature and 175 °C, respectively. Compared to the reported UV detectors with material of 4H-SiC or β-SiC, the developed n-SiCN/p-SiCN homojunction has better current ratio in both room and elevated temperature.     

An investigation into the structure of aqueous NaCl electrolyte solutions under magnetic fields

Molecular dynamics simulations are performed to investigate the effects of magnetic fields with intensities of 1–10 T on aqueous NaCl electrolyte solutions at 298 K. The simulations employ the F3C (flexible three centered) water model and investigate electrolyte solutions with both low (1 M) and high (5 M) NaCl concentrations. The results show that the self-diffusion coefficient of the water molecules decreases in a low-concentration solution as the magnetic field intensity is increased, but increases in a high-concentration solution. The magnetic field enhances the mobility of the Na⁺ and Cl⁻ ions in both low- and high-concentration solutions. The average number of hydrogen bonds increases when the magnetic field is applied to pure water or to a solution with a low NaCl concentration, but decreases in a solution with a high-concentration. The results show that the enhanced mobility of the ions under a magnetic field causes serious damage to the hydrogen bond network in the high-concentration solution. Conversely, in the low-concentration solution, the structural behavior is dominated by the properties of the water molecules, and hence the hydrogen bonding ability is enhanced as the magnetic field is increased.