"Pored-domes" of the fenestrated endotheliocyte of the glomerular and peritubular capillaries in the rodent kidney.

The fenestrated endotheliocyte of peritubular and glomerular capillaries in rat and mouse kidneys were observed with SEM and TEM. In the glomerular capillary, so-called "pored-domes" were found not only at the fenestrated areolae but also at the nuclear region of the endotheliocyte. At the region between filtration surface and nuclear region, they accumulated to construct a sponge-like structure. The endotheliocyte of peritubular capillary also showed small "pored-domes". The size and morphology of the pores in the "pored-domes" of glomerular and peritubular capillaries were similar to those of areolae fenestratae of the respective capillary. Based on the findings, we assumed that pored-domes and the sponge-like structure are the reservoir for the fenestrated area of the endotheliocyte to accommodate the rapid expansion of capillary lumen.     

A mathematical morphology approach to Euclidean distancetransformation

A distance transformation technique for a binary digital image using a gray-scale mathematical morphology approach is presented. Applying well-developed decomposition properties of mathematical morphology, one can significantly reduce the tremendous cost of global operations to that of small neighborhood operations suitable for parallel pipelined computers. First, the distance transformation using mathematical morphology is developed. Then several approximations of the Euclidean distance are discussed. The decomposition of the Euclidean distance structuring element is presented. The decomposition technique employs a set of 3 by 3 gray scale morphological erosions with suitable weighted structuring elements and combines the outputs using the minimum operator. Real-valued distance transformations are considered during the processes and the result is approximated to the closest integer in the final output image.     

On 2-D recursive LMS algorithms using ARMA prediction for ADPCMencoding of images

A two-dimensional (2D) linear predictor which has an autoregressive moving average (ARMA) representation well as a bias term is adapted for adaptive differential pulse code modulation (ADPCM) encoding of nonnegative images. The predictor coefficients are updated by using a 2D recursive LMS (TRLMS) algorithm. A constraint on optimum values for the convergence factors and an updating algorithm based on the constraint are developed. The coefficient updating algorithm can be modified with a stability control factor. This realization can operate in real time and in the spatial domain. A comparison of three different types of predictors is made for real images. ARMA predictors show improved performance relative to an AR algorithm.     

2.488 Gb/s-318 km repeaterless transmission using erbium-dopedfiber amplifiers in a direct-detection system

The authors have achieved a 2.488 Gb/s, 318 km repeaterless transmission without any fiber dispersion penalty through a nondispersion-shifted fiber in a direct detection system. The system was loss limited with a T-R power budget of 57 dB. Three key components enabled the authors to achieve this result: (1) a Ti:LiNbO₃ external amplitude modulator enabling a dispersion-free transmission, (2) erbium-doped fiber amplifiers increasing the transmitting power to +16 dBm, and (3) an erbium-doped fiber preamplifier enabling a high-receiver sensitivity of -4.1 dBm for 10^-9 BER. To the author's knowledge, this result is the longest repeaterless transmission span length ever reported for direct detection at this bit rate. From the experimental results and a theoretical model, the authors identified the sources of the receiver sensitivity degradation from the quantum limit (-48.6 dBm) and estimated the practically achievable receiver sensitivity of ~-44 dBm (~-124 photons/bit) for 2.5 Gb/s optical preamplifier detection     

Optical neurochip with learning capability

A dynamic optical neurochip with variable synaptic interconnection capability has been reported. A novel type of photodetector called a variable sensitivity photodetector has been developed for the synaptic interconnection of neural networks. It utilizes a metal-semiconductor-metal structure whose quantum efficiency can be modulated by an applied bias voltage. The fabricated dynamic optical neurochip consists of an 8×8 variable sensitivity photodetector (VSPD) array and an 8 line-shaped LED array. It is shown that this device is suitable for learning in neural networks. The application to pattern classification is demonstrated     

Human body detection in wet snowpack by an FM-CW radar

An FM-CW radar system was applied to detect a human body buried in a very wet snowpack. This radar uses the L-band microwave frequency with a maximum output power of 100 mW, and utilizes digital signal processing techniques. Field experiments were carried out to detect and map a human body embedded at a depth of 125 cm in a natural snowpack. The radar is shown to have a potential ability to detect avalanche victims, indicating that it may become a tool for snow rescuer operations     

A design technique for a high-gain, 10-GHz class-bandwidth GaAsMESFET amplifier IC module

A design procedure is proposed for a high-gain and wideband IC module, using stability analysis and a unified design methodology for ICs and packages. A multichip structure is developed using stability analysis and the requirements for stable operation are determined for each IC chip, package, and interface condition between them. Furthermore, to reduce the parasitic influences, several improvements in the interface and package design are clarified, such as wideband matching and LC resonance damping. IC design using effective feedback techniques for enlarging the bandwidth are also presented. The ICs are fabricated using 0.2-μm GaAs MESFET IC technology. To verify the validity of these techniques, an equalizer IC module for 10-Gb/s optical communication systems was fabricated, achieving a gain of 36 dB and a bandwidth of 9 GHz     

Temperature-compensation circuit techniques for high-density CMOSDRAMs

Temperature-compensation circuit techniques are presented for the CMOS DRAM internal voltage converter, the RC-delay circuit, and the back-bias generator, which do not need any additional process steps. The above-mentioned circuits have been designed and evaluated through a 16-Mb CMOS DRAM process. These circuits have shown an internal voltage converter (IVC) with an internal voltage temperature coefficient of 185 ppm/°C, and an RC-delay circuit with a delay time temperature coefficient of 0.03%/°C. As a result, a 6.5-ns faster RAS access time and improved latchup immunity have been achieved, compared with conventional circuit techniques     

Self-aligned silicide technology for ultra-thin SIMOX MOSFETs

The salicide technology using rapid thermal annealing was applied to MOSFETs on thin-film SOI. Since the SOI film was limited to a thickness of less than 100 nm, the silicidation reaction between Ti and Si atoms on the SOI surface exhibited new features that depended on the initial thickness of the deposited Ti. There was an optimum thickness of as-deposited Ti on silicidation due to the restricted thickness of the Si layer. Beyond the optimum point, the region adjacent to the silicided Si layer works as a Si source to assure stoichiometric TiSi₂. The subthreshold slopes and carrier mobilities were not changed by the salicide process. Junction leakage characteristics were slightly degraded; however, the change was small enough for device application. The influence on AC characteristics was well demonstrated for a high-speed CMOS ring oscillator with a gate length of 0.7 μm. The minimum delay time/stage was 46 ps/stage at 5 V. This gives 1.8 times higher speed operation than the controlled bulk CMOS ring oscillators with the same design rule     

A digital technique to estimate second-order distortion usinghigher order coherence spectra

A digital spectral method for evaluating second-order distortion of a nonlinear system, which can be represented by Volterra kernels up to second order and which is subjected to a random noise input, is discussed. The importance of departures from the commonly assumed Gaussian excitation is investigated. The Hinich test is shown to be an appropriate test for orthogonality in the system identification. Tests for Gaussianity of two important sources, which are commonly used for Gaussian inputs in nonlinear system identification, are presented: (1) commercial software routines for simulation experiments, and (2) noise generators for practical experiments. The deleterious effects of assuming a Gaussian input when it is not are demonstrated. The random input method for evaluating the second-order distortion of a nonlinear system is compared with the sine-wave input method using both simulation and experimental data. The approach is applied to a loudspeaker in the low-frequency band