Photoacoustic spectroscopy (PAS) has recently received much attention especially for plant photosynthesis research, because this technique is capable of performing non-destructive measurement without any pre-treatment of specimens. So far we have developed a PAS system equipped with an open photoacoustic cell (OPC), which allows in situ and in vivo measurements of plant photosynthesis of intact undetached leaves. In this study, we have measured photosynthesis reaction using OPC and developed a Confocal Scanning Photoacoustic Microscopy (CSPAM) system, in which PAS is combined with confocal scanning laser microscopy. The system allows simultaneous measurement of acoustic signal and another signal such as fluorescence, and also gives two- and three- dimensional intensity distributions of these signals, thereby giving two- and three- dimensional information about photosynthetic activity of plants.

Micropatterning of organosilane self-assembled monolayers (SAMs) was demonstrated on the basis of photolithography using an excimer lamp radiating vacuum ultra-violet (VUV) light of 172 nm in wavelength. This lithography is generally applicable to micropatterning of organic thin films including alkyl and fluoroalkyl SAMs, since its patterning mechanism involves cleavage of C-C bonds in organic molecules and subsequent decomposition of the molecules. In this study, SAMs were prepared on Si substrates covered with native oxide by chemical vapor deposition in which an alkylsilane, that is, octadecyltrimethoxysilane [CH3(CH2)17Si(OCH3)3, ODS] or a fluoroalkylsilane, that is, 1H, 1H, 2H, 2H-perfluorodecyltrimethoxy-silane [CF3(CF2)7CH2CH2Si(OCH3)3, FAS] were used as precursors. Each of these SAMs was photoirradiated through a photomask placed on its surface. As confirmed by atomic force microscopy and x-ray photoelectron spectroscopy, the SAMs were decomposed and removed in the photoirradiated area while the masked areas remained undecomposed. A micropattern of 2 µm in width was successfully fabricated. Furthermore, microstructures composed of two different SAMs, that is, ODS and FAS, were fabricated as follows. For example, an ODS-SAM was first micropatterned by the VUV-lithography. Since, the VUV-exposed region on the ODS-SAM showed an affinity to the chemisorption of organosilane molecules, the second SAM, i. e. , FAS, confined to the photolithographically defined pattern was successfully fabricated. Due to the electron negativity of F atoms, the FAS covered region showed a more negative surface potential than that of the ODS surface: its potential difference was ca. 120 mV as observed by Kelvin probe force microscopy.

We propose a new sampling control system on image sensor array. Contrary to the random access pixels, the proposed sensor is able to read out spatially variant sampled pixels at high speed, without inputting pixel address for each access. The sampling positions can be changed dynamically by rewriting the sampling position memory. The proposed sensor has a memory array that stores the sampling positions. It can achieve any spatially varying sampling patterns. A prototype of 64 64 pixels are fabricated under 0.7 µm CMOS precess.

We propose here a time-domain shooting algorithm for calculating the steady-state responses of nonlinear RF circuits containing parasitic elements that is based on both a modified Newton and a secant methods. Bipolar transistors and MOSFETs in ICs have small parasitic capacitors among their terminals. We can not neglect them because they will gives large effects to the shooting algorithm at the high frequency. Since our purpose is to develop a user friendly simulator, we mainly take into account the relatively large normal capacitors such as coupling and/or by-pass capacitors and so on, because the parasitic capacitors are usually smaller and contained in the device models. We have developed a very simple simulator only using the fundamental tools of SPICE, which can be applied to relatively large scale ICs, efficiently.

This letter presents a subspace-based technique with generalized sidelobe canceler structure, which can be utilized to deal with the desired user's SNR < 0 dB. With an estimate scheme of the desired user code, the proposed method offers more robustness against spreading code mismatch. Computer simulations show that the effectiveness of the proposed detector.

In this paper, we present a new approach for the design of partially adaptive broadband beamformers with the generalized sidelobe canceller (GSC) as an underlying structure. The approach designs the blocking matrix involved by utilizing a set of P-regular, M-band wavelet filters, whose vanishing moment property is shown to meet the requirement of a blocking matrix in the GSC structure. Furthermore, basing on the subband decomposition property of these wavelet filters, we introduce a new dynamic subband selection scheme succeeding the blocking matrix. The scheme only retains the principal subband components of the blocking matrix outputs based on a prescribed statistical hypothesis test and thus further reduces the dimension of weights in adaptive processing. As such, the overall computational complexity, which is mainly dictated by the dimension of adaptive weights, is substantially reduced. The furnished simulations show that this new approach offers comparable performance as the existing fully adaptive beamformers but with reduced computations.

This paper discusses the employment of adaptive array antennas at the base station of a Multi Processing Gain (MPG) CDMA system. It is shown that the adaptive array antenna with the weight control scheme based on the signal before despreading procedure does not increase but even decreases the performance than that with an omni-directional antenna, and the cause of this serious performance degradation is revealed. Then it is shown that the performance with the weight control scheme based on the signal after despreading procedure is always better than that with an omni-directional antenna. Furthermore, the possibilities of performance improvement by the combination of adaptive array antenna and interference cancellation techniques are mentioned.

In this paper, system capacity of the reverse link of a wireless multimedia CDMA system with transmission power control is analysed for receivers with and without CCI cancellers. For N classes of users, system capacity is represented by a point in an N-dimensional space. It is shown that system capacity is improved considerably with CCI cancellers, that system capacity region is non-convex in general, and that its boundary is well approximated with a unique hyper plane when CCI cancellers are fully employed.

A head-disk spacing tester that includes the effect of lubricant will be necessary if the slider-disk interaction is to be considered. The interaction and interaction induced spacing variation can be quantitatively characterized by optical method and by replacing the functional disk media with a glass disk covered with a carbon layer and a lubricant layer of the same materials and the same layer thickness as the functional disk media. This paper reports a tester configuration based on that concept. Experimental investigations into the nanometer spaced head-disk interface with such a setup are presented also. Results indicate that the lubricant plays an important role in slider-disk interaction and the vibration of the slider-disk interface. Two types of interface vibration were noticed: contact vibration and bouncing vibration. For the bouncing case, the natural frequency of air-bearing and its fold frequencies will be excited and air-bearing plays more important role in the determination of the slider vibration, comparing with the contact-vibration case.

This paper introduces an acoustic echo canceller system materialized with a 16-bit fixed point processing type DSP (Analog Devices, ADSP-2181). This experimental system uses the tri-quantized-x individually normalized least mean square (INLMS) algorithm little degrading the convergence property under the fixed point processing. The experimental system also applies a small step gain to the algorithm to prevent the double-talk from increasing the estimation error. Such a small step gain naturally reduces the convergence speed. The experimental system compensates the reduction by applying the block length adjustment technique to the algorithm. This technique enables to ceaselessly update the coefficients of the adaptive filter even when the reference signal power is low. The experimental system thus keeps the echo return loss enhancement (ERLE) high against the double-talk.

This paper presents an algorithm for the scan-chain optimization problem in multiple-scan design methodology. The proposed algorithm, which consists of four phases, first determines pairs of scan-in and scan-out pins (Phase 1), and then assigns flip-flops to scan-paths by using a graph theoretical method (Phase 2). Next the algorithm decides connection-order of flip-flops in each scan-path by using TSP (Traveling Salesman Problem) heuristics (Phase 3), and finally exchanges flip-flops among scan-paths in order to reduce total scan-path length (Phase 4). Experiments using actual design data show that, for ten scan-paths, our algorithm achieved a 90% reduction in scan-test time at the expense of a 7% total scan-path length increase as compared with the length of a single optimized scan-path. Also, our algorithm produced less total scan-path length than other three possible algorithms in a reasonable computing time.

In order to guarantee pairwise independence of codewords in an ensemble of convolutional codes it is necessary to consider time-varying codes. However, Seguin has shown that the pairwise independence property is not strictly necessary when applying the random coding argument and on this basis he derives a new random coding bound for rate 1/n fixed convolutional codes. In this paper we show that a similar random coding bound can be obtained for rate k/n fixed convolutional codes.

This paper proposes an adaptive noise canceller with low signal-distortion in the presence of crosstalk. The proposed noise canceller has two pairs of cross-coupled adaptive filters, each of which consists of the main filter and a sub filter. The signal-to-noise ratios (SNRs) of the primary and the reference signals are estimated by the sub filters. To reduce signal distortion at the output of the adaptive noise canceller, the step sizes for coefficient adaptation in the main filters are controlled according to the estimated SNRs. Computer simulation results show that the proposed noise canceller reduces signal distortion in the output signal by up to 15 dB compared to the conventional noise canceller.

Active frequency-tuning beam-scanning leaky-mode antenna arrays have been demonstrated in this paper. These antennas integrated one or several microstrip leaky-wave antenna elements with a single varactor-tuned HEMT VCO as an active source. Noted that the measured scan angles of the 11 and 14 antennas were approximately 24 and the scanning range of the 12 antenna was 20. Furthermore, reflected wave due to the open end of each leaky-wave antenna element has been suppressed by the symmetric configuration of this antenna array and the antenna efficiency increases. When comparing with the measured radiation pattern of the single element antenna, we found that the 12 and 14 antenna arrays can effectively suppress the reflected power by more than 5.5 dB and 10.5 dB, respectively, at 10.2 GHz. The power gain are more than 2 dB and 3.16 dB higher than the single element antenna with a measured EIRP of 18.67 dBm.

In coupled oscillator arrays, it is possible to control the inter-element phase shift up to 180 by free-running frequency distribution based on injection-locking phenomenon. In this paper, a new technique to control the inter-element phase shift electronically up to the maximum extent of 360 is reported. Oscillators are unilaterally coupled to the preceding oscillator through one of the two paths, which differ from each other 180 in electrical length and each includes an amplifier. Turning on the desired amplifier one can control the phase shift either -180 to 0 or 0 to 180. The technique was applied in a three-element oscillator array each coupled to a patch antenna via a round aperture. The radiation beam of the array could be scanned 47 in total.

The rosette-scanning infrared seeker (RSIS) is a tracker that a single infrared detector scans the total field of view (TFOV) in a rosette pattern, and then produces 2D image about a target. Since the detected image has various shapes in accordance with the target position in the TFOV, it is difficult to determine a precise target position from the obtained image. In order to track this type of target, therefore, we propose an efficient tracking method using the K-means algorithm (KMA). The KMA, which classifies image clusters and calculates their centers, is used to cope with an countermeasure (CM) such as an IR flare. To evaluate the performance of the RSIS using the KMA dynamically, we simulate the RSIS in the various conditions, and discuss the tracking results.

Recent years have seen great advances in our understanding and modeling of the coupled diffusion of dopants and defects in silicon during integrated circuit fabrication processes. However, the ever-progressing shrinkage of device dimensions and tolerances leads to new problems and a need for even better models. In this review, we address some of the advances in the understanding of defect-mediated diffusion, focusing on the equations and parameters appropriate for modeling of dopant diffusion in submicron structures.

The architecture and control procedure for a direct conversion receiver are investigated for a linear modulation scheme. The proposed design techniques maintain receiver linearity despite various types of signal distortion. The techniques include the fast gain control procedure for receiving a control channel for air interface connection, DC offset canceling in both analog and digital stages, and 2nd-order intermodulation distortion canceling in an analog down-conversion stage. Experimental and computer simulation results on PHS (Personal Handy-phone System) parameters, showed that required linear modulation performance was achieved and thus the applicability of the proposed techniques was demonstrated.

An Acoustic echo canceller has problems adaptating under noisy or double-talk conditions. The adaptation process requires a precise identification of the temporarily changed room impulse response. To do this, both minimizing the step size parameter of the Least Mean Square (LMS) method to be as small as possible and giving up on updating the adaptive filter coefficients have been considered. This paper describes an adaptive cross-spectral technique that is robust to adaptive filtering under noisy or double-talk conditions and for colored signals such a speech signal. The cross-spectral technique was originally developed to measure the impulse response in a linear system. Here we apply in the adaptive cross-spectral technique to solve the acoustic echo cancelling problem. This cross-spectral technique takes the ensemble average of the cross spectrum between input and error signals and the averaged cross spectrum is divided by the averaged power spectrum of the input signal to update the filter coefficients. We have confirmed that the echo signal is suppressed by about 15 dB even under double-talk conditions. We also explain that this method has a systematic error due to using a short time block for estimating the room impulse response. Then we investigate overlapping every last half block by the following first half block in order to reduce the effect of the systematic error. Finally, we compare our method with the Frequency-domain Block LMS (FBLMS) method because both methods are implemented in the frequency domain using a short time block.

This paper analyzes the performance of direct-detection optical CDMA systems with single optical hard-limiter using equal-weight orthogonal (EWO) signaling. Moreover, this paper clarifies the basic structure and the performance of the system using time-shifted versions of optical orthogonal code (OOC's) as EWO signaling. The system assigns the time-shifted versions of OOC's to the transmission of bits "0" and "1," respectively. Thus, the system does not require dynamic estimation of the receiver threshold. The performance is analyzed under the Gaussian approximation of an avalanche photodiode (APD) output where the effects of APD noise, thermal noise and interference are included. From the theoretical analysis and numerical results, it is shown that the system has good performance without dynamic estimation of the receiver threshold.