Fabrication of soft reflective microoptical elements using a replication process

This paper reports the fabricated method and optical performance of soft, reflective elements with nonspherical surface. Based on excimer laser microdrilling and spin coating processes, a PMMA film suspended on microdrilled holes was used as a concave mold. Then, a high-reflectance material, mixed PDMS rubber polymers with TiO₂ nanoscale powders, was cast on the PMMA mold. Finally, both of concave and convex elements could be fabricated through soft replica molding processes and these elements could directly reflect light without the deposition of metal coatings. Therefore, we proposed a model regarding a flexible cable with its weight suspended on fixed points to explain the formation mechanism of PMMA molds. With the change of diameters of microholes and thicknesses of PMMA films, the suspended height of films was surely controllable. Therefore, the curvature radiuses and shapes of these aspherical elements also depended on the diameters of microholes and the thicknesses of PMMA films. Experimental results demonstrated that soft reflective elements have good surface qualities and high-quality optical properties. Besides, all fabrication steps can be executed in ambient environment and at low temperature, the proposed method has a potential for mass production.     

High-resolution determination of soft tissue deformations using MRI and first-order texture correlation

Mechanical factors such as deformation and strain are thought to play important roles in the maintenance, repair, and degeneration of soft tissues. Determination of soft tissue static deformation has traditionally only been possible at a tissue's surface, utilizing external markers or instrumentation. Texture correlation is a displacement field measurement technique which relies on unique image patterns within a pair of digital images to track displacement. The technique has recently been applied to MR images, indicating the possibility of high-resolution displacement and strain field determination within the mid-substance of soft tissues. However, the utility of MR texture correlation analysis may vary amongst tissue types depending on their underlying structure, composition, and contrast mechanism, which give rise to variations in texture with MRI. In this study, we investigate the utility of a texture correlation algorithm with first-order displacement mapping terms for use with MR images, and suggest a novel index of image "roughness" as a way to decrease errors associated with the use of texture correlation for intra-tissue strain measurement with MRI. We find that a first-order algorithm can significantly reduce strain measurement error, and that an image "roughness" index correlates with displacement measurement error for a variety of imaging conditions and tissue types.     

Sub-100 nm space pattern replication by using a cross-sectioned X-ray mask

Ultra-fine space pattern printing by Synchrotron Radiation x-ray lithography was investigated. New types of cross-sectioned mask¹⁾ were used to overcome the difficulty of mask fabrication. As a result, feasibility to print space patterns with a width of 50 nm or less by contact printing was demonstrated. In practice, a very narrow mask-to-wafer gap setting and precise control of the x-ray irradiation angle are necessary.     

The soft option [industrial PLC replication]

This paper examines whether a PC could replicate the control functions of a programmable logic controller. The author reviews the issues behind this big debate in the industrial control arena     

High-resolution phase sampled interferometry using symmetricalnumber systems

This paper identifies a new phase sampling interferometer approach that can he easily incorporated into the established techniques to provide a high resolution, small-baseline array with a fewer number of phase sampling comparators. The approach is based on preprocessing the received signal using symmetrical number systems (SNS). Antennas based on both an optimum symmetrical number system (OSNS) and a robust symmetrical number system (RSNS) are investigated. The SNS preprocessing is used to decompose the spatial filtering operation into a number of parallel suboperations (moduli) that are of smaller computational complexity. A much higher direction finding (DF) spatial resolution is achieved after the N different moduli are used and the results of these low precision suboperations are recombined. By incorporating the OSNS or RSNS preprocessing concept, the field of view of a specific configuration of interferometers and phase sampling comparator arrangements can be analyzed exactly. The OSNS gives the maximum dynamic range or number of spatial resolution bins while the RSNS reduces considerably the number of possible encoding errors. Experimental results for both a 5-bit OSNS and a 6-bit RSNS array are compared. The errors in the encoding of the direction of arrival are quantified for both architectures     

High-resolution spectral analysis using multiple-interval adaptive prediction

The problem of adaptively detecting two sinusoids corrupted by noise is considered, with emphasis on resolution properties. The approach is to form a spectral estimate from the coefficients of a Δ-step-ahead adaptive predictor. A theoretical analysis reveals that attention to the choice of the prediction horizon Δ gives a distinct improvement in the spectral estimate and in the resolution of the signals. The theoretical results are illustrated with numerical examples. Comparisons with previously suggested techniques are also made.     

High-resolution neural temperature sensor using fiber Bragggratings

We demonstrate a novel high-resolution neural temperature sensor using two fiber Bragg gratings (FBG's) and a modular artificial neural network which is used to learn the mapping relation among frequency, temperature, and the normalized transmission power spectrum. Because of the fast computational ability of the modular artificial neural network and the sensitivity of FBG's, the sensor can make high-resolution temperature and frequency measurements in real time. The experimental results show that the temperature resolution of this sensor can reach 0.005°C     

Signal processing and pattern recognition with soft computing

We describe the overall role of soft computing (SC) in signal processing and pattern recognition (SPPR) with specific applications to biomedical engineering, geoscience for mining and civil engineering human interfaces, and image processing. Detection of characteristic points in an electrocardiogram to implement an advanced ECG analyzer is presented which is carried out using both conventional SPPR techniques and self-organizing neural networks. Successful technologies for monitoring a geostructure by supervised and self-organizing neural networks are described. Identification of a freehand drawing by a combination of fuzzy logic and neural networks is also described. Moreover, application of fuzzy logic to image segmentation is presented. Finally, innovation of SPPR using SC technologies is discussed     

High-resolution radar imaging using 2-D linear prediction

An algorithm for radar imaging is described. The algorithm is based on two-dimensional (2-D) linear prediction of 2-D Cartesian frequency spectra. It is shown that the algorithm provides much better resolution than the ISAR image obtained using a 2-D inverse Fourier transform. The algorithm is especially useful for imaging targets using small-bandwidth RCS data over limited aspect angle regions     

The effect of cosmic rays on the soft error rate of a DRAM atground level

This paper provides conclusive evidence that cosmic rays cause soft errors in commercial dynamic RAM (DRAM) chips at ground level. Cosmic-ray-induced soft errors in electronic components have long been a problem for the designers of satellites and spacecraft, but they have not generally been considered to be an important influence on memory chip soft error rate (SER) in terrestrial environments. In an experiment designed to determine the effect of cosmic radiation on the SER of a sample of DRAM chips at ground level, the SER of a large number of chips was measured at various locations and altitudes around the US: near sea level in Essex Junction, VT; 200 m underground in a Kansas salt mine; at an altitude of 1.6 km in Boulder, CO; and at 3.1 km in Leadville, CO. The results reported here show that even at sea level there is a significant component of the SER that can be attributed to the effects of cosmic rays, and that the magnitude of the effects increases dramatically at higher altitudes     

High-resolution proximity sensor using flexible semi-transparent organic photo detector

We propose a flexible proximity sensor to detect sub-centimeter distance with an ultra-high displacement resolution. The proximity sensor is realized by integrating a semi-transparent organic photo detector with a transparent top electrode and a finger-type bottom electrode. By placing the semi-transparent finger-type photodetector on a light source, such as a light-emitting diode (LED), the photodetector can detect the light reflected from an object on top of the sensor. With the highly compact structure, the detecting range is from 1 mm to 30 mm. From 1 mm to 10 mm, the sensor is particularly sensitive and delivers a resolution of 1 mm. The air-stable photodetector can also be fabricated on a flexible substrate without encapsulation, enabling the integration with arbitrary light sources. After 1000 times bending, the flexible photodetector shows no obvious degradation.     

High-resolution direction finding of non-stationary signals using matching pursuit

One of the main goals of time–frequency (TF) signal representations in non-stationary array processing is to equip multi-antenna receivers with the ability to separate sources in the TF domain prior to direction finding. This permits high-resolution direction-of-arrival (DOA) estimation of individual sources and of more sources than sensors. In this paper, we use linear decomposition of sensor data based on matching pursuit (MP). The leading atoms of the MP, which capture most of the source TF signatures, can be different for different sources and, as such, provide the desired source discrimination. The MP coefficients with high signal-to-noise ratio (SNR) and corresponding to the leading decomposition atoms are used to develop the MP-MUSIC DOA estimation for non-stationary source signals. We demonstrate the source discriminatory capability of the proposed technique using linear FM, nonlinear FM, and other non-stationary signals. Further, we compare MP-MUSIC performance with conventional MUSIC and the time–frequency MUSIC, which incorporates bilinear transforms.     

Efficient ARQ technique using soft demodulation

In the letter a new technique for increasing the efficiency of an automatic-repeat-request communication system is described. This technique uses all the received versions of a codeword, and also those versions containing errors. Such a strategy, together with a soft demodulation of each received symbol, is particularly efficient when applied to ARQ schemes in which each block erroneously received is retransmitted many times.     

High-resolution full-color LCD driven by OTFTs using novel passivation film

A full-color twisted-nematic type liquid crystal display (TN-LCD) of 1.4-in diagonal size driven by organic thin-film transistors (TFTs) has been fabricated. This TN-LCD has 80/spl times/80/spl times/3 (RGB) pixel arrays addressed by pentacene TFTs with a channel width of 50 /spl mu/m. The contact resistance between the pentacene film and the source/drain electrodes has been reduced by selecting the exposure condition of the photoresist in patterning the electrodes. In addition, a solution-processed passivation film with a novel structure, consisting of photosensitive polyvinylalcohol and organosiloxane glass resin, has been developed to protect the TFTs against degradation induced by integration with TN-LCD devices. Consequently, it has been confirmed that the organic-TFT-driven TN-LCD fabricated in this paper is capable of displaying full-color moving images at a resolution of 80 pixels per inch.     

High-resolution, current-mode A/D convertors using active currentmirrors

An improved current-mode algorithmic A/D convertor (ADC), using active current mirrors, is described. These mirrors eliminate current mismatches due to the transistor's finite output resistance, allowing the construction of higher-resolution ADCs than is possible using simple current mirrors     

软切换参数对CDMA1X性能的影响及优化

分析并仿真得到了在CDMA1X系统中,不同业务负载情况下的软切换开销因子与静态和动态软切换门限,以及导频信道功率比例等参数的关系,并在此基础上提出了相应的网络优化措施。仿真采用蒙特卡罗"快照"法,并在进行传播损耗计算时加入了阴影衰落的影响。     

7A11--Laser induced emission of electrons, ions, and X rays from solid targets

We have first studied the spatial distribution of electrons and ions emitted from a solid target when hit by a focused,Q-switched laser beam. The particle emission is highly anisotropic. In a second experiment we have analyzed the ion energy for various targets such as beryllium, carbon, and molybdenum. For each target element, evidence for multicharged ions has been shown as a function of laser intensity. With a laser flux at the target surface of6 times 10^{10}W/cm², the maximum ion energy obtained is about 2 keV. Finally, we have shown that particle emission is accompanied by X-ray emission.     

Large area pattern replication by nanoimprint lithography for LCD–TFT application

Nanoimprint lithography is a high-throughput, low-cost, non-conventional lithographic method for fabricating micro/nanoscale patterns. In this study, we will present recent achievement in developing nanoimprint lithography for LCD–TFT fabrication. We fabricated metal gate for LCD–TFT with imprinting process. First, mold is pressed into a thin resist cast on a Cr layer which is deposited on a glass substrate. And the pressed resin is exposed to UV for curing, followed by demolding process. To acquire metal gate for LCD–TFT, subsequent process such as RIE with O₂ Plasmas, wet etching of Cr and striping of remained resin is followed. Finally, the fabricated metal gate has 3.5 μm level width, 97% uniformity overall on 1G size in a single imprint. Herewith nanoimprint lithography can substitute conventional photolithography steps in LCD–TFT process. Also it is expected that large area fine pattering such as functional optical films and PCBs could be effectively produced by nanoimprint process.     

High-resolution direction finding using eigendecomposition based estimators and joint estimation strategy

A new direction-finding method with high estimation performance is proposed. This method jointly and simultaneously employs the standard MUSIC procedure and the generalisation of the minimum-norm procedure for resolving multiple signal sources. Simulation results show the improved performance of the proposed method as compared to the original MUSIC and minimum-norm methods.<>