A Microprocessor for Speech Recognition

A new single-chip microprocessor for speech recognition, the SRP, has been developed, utilizing a multiprocessor architecture and a pipelined structure. It can recognize up to 340 isolated words or 40 connected words in real time. The SRP contains a vector distance calculator, a DP-equation calculator, and an I/O controller operating in a pipelined manner. Algorithm variations and operation parameters are user programmable, and the total size of the SRP program for a typical speech recognition system is about 700 words. The device has been fabricated with n-channel Si-gate E/D MOS technology with 2.5 μm design rules and employs 7296 three-transistor dynamic RAM cells for a total of more than 40 000 transistors.     

Morphological study on thermal treatment and degradation behaviors of solution-grown poly(l-lactide) single crystals

Morphological changes of solution-grown crystals (SGCs) of poly(l-lactide) (PLLA) following thermal treatment and enzymatic degradation were investigated using atomic force microscopy in terms of defects in the crystals. PLLA SGCs were grown from a dilute solution of acetonitrile at 5 °C. The obtained solution-grown monolamellar crystals have a lozenge-shaped morphology containing unique dimensions, with one side measuring 12 μm. To investigate enzymatic degradation behavior, PLLA SGCs were incubated in buffered solution with proteinase-K at 37 °C. The initial stage of enzymatic degradation of PLLA SGCs with proteinase-K occurs in loosely folding chains at the surface of the crystal. Thermally treated PLLA SGCs below the melting temperature showed an increase of the lamellar thickness of the SGCs at the treated temperature and partial surface erosion following enzyme exposure. These results indicate that less ordered chains exist throughout the lamellae and their thermal-induced chain extension makes them more susceptible to enzyme attack.     

Some properties of thin aluminium nitride films formed in a glow discharge

The formation of thin AlN films and some of their electrical properties have been investigated. The films were prepared by exposing the surface of evaporated aluminium films to a glow discharge in pure nitrogen gas. It has been confirmed by transmission electron diffraction that the structure of the film is of the wurtzite type, as is that of the bulk material. It was observed that the thickness of the AlN films depends on the voltage of the glow discharge, the distance from the discharge electrode to the films and the treatment time. The electrical properties were measured in the form of a sandwich diode, i.e. Al-AlN-Au. The voltage-controlled negative resistance, which was first discovered in Al-Al₂O₃-metal diodes, has also been observed in this nitride film diode and shows very good reproducibility and stability.     

吲哚荷尔蒙自由基脉冲辐解光谱及其酸基平衡和还原电位性质研究

The Absorption spectral, acid-base equilibrium potential properties and formation and decay kinetics of four kinds of radicals from natural existing indole hormones were studied by pulse radiolysis.One of the most important properties for these four indolyl hormones, melatonin, 5-methoxygramine (MTA),5-methoxy-N, N-dimethylthytrytamine (DMM TA) and 5-methoxy-N, N-diethylthytrytamine (DEMT A), which are involved in biochemical processes and play crucial roles in many neuropathy and cancer related diseases, is their facile one electron oxidation with formation of radical cations or their conjugated base, the indolyl radicals.Formation kinetics and properties of the radicals were investigated by pulse radiolysis using the Linac accelerator with fast time-resolving optical system in UTNL.In the present study, these radicals were generated through oxidation of the corresponding hormone with azide radical in radiation induced process. Their spectroscopic properties were investigated and it was found that the transient spectra in all these cases exhibit similar absorption and pH dependence: in acidic solution, the radicals are characterized with three absorption maxima around 320-350, 440-460, 520-550nm. The spectra of MTA at various pH were shown as an example. From the absorption changes as a function of pH, two pK values were determined to be around 5 and 9 for the indolyl radicals except for melatonin, in which, only one pK was distinguished to be 4.4. Formation kinetics of the radicals was measured by following the growth of their absorption peaks and it was found that these indolyl derivatives transfer an electron to N3, with different rate constants, i.e.1.2×1010, 4.5×109, 4.9×109, 1.6×109 dm3 mol-1 s-1 for melatonin, MTA, DMMTA, and DEMTA, respectively.Reduction potentials of the radicals vs their molecules were also determined and they are dependent on the pH of medium. At pH 7, the reduction potentials were estimated to be 1.10, 1.18, 1.18, 1.20eV for melatonin, MTA,DMMTA and DEMTA, respectively. Because of its relatively high contents in human brain cells, melatonin is the main antioxidant among hormones against the oxidizing species in brain cells.     

Transport properties of undoped Cd0.9Zn0.1Te grown by high pressure bridgman technique

The electron drift mobility of undoped Cd_0.9Zn_0.1Te grown by high-pressure Bridgman method is measured by a time-of-flight technique. The sample shows a room temperature mobility and mobility lifetime product of 950 cm²/Vs and 1.6 × 10⁻⁴cm²/V, respectively. The mobility increases monotonically with decreasing temperature to 3000 cm²/Vs at 100 K. The dominant scattering mechanism for the electron transport is discussed by comparing with the theoretical mobility obtained by iterative solution of the Boltzmann equation.     

Global open ethernet (GOE) system and its performance evaluation

This paper presents an overview of global open Ethernet (GOE) architecture as a cost-effective Ethernet-based virtual private network (VPN) solution, and discusses a hardware and software implementation of a prototype system. Three main approaches have been proposed for a VPN solution on metro-area network: resilient packet ring, Ethernet over multiprotocol label switching (EoMPLS), virtual bridged local area network-tag stacking (Q-in-Q). None of these schemes can satisfy the following requirements at the same time: network topology flexibility, affordable network functionalities, low equipment cost, and low operational cost. The proposed GOE system is designed to solve VPN management problems of these approaches with MPLS VPN functionality at a low cost of Ethernet-based solution. The key components of GOE are: 1) a novel GOE tag for high-speed switching and 2) a novel routing and protection module via per-destination multiple rapid spanning tree protocol (PD-MRSTP). Via the analytical performance evaluation of EoMPLS, Q-in-Q, and GOE, we show that the memory cost and the network utilization of GOE is two-three times smaller and 22% higher than the other approaches, respectively. We also have developed a GOE prototype system and obtained the following remarkable hardware and software performance results. The GOE core switch delivered 100% of theoretical maximum throughput (10 G) with zero packet loss even with the field programmable gate array platform, and its 10-G port density is 1.5 times denser than the best currently available products. The GOE switch using PD-MRSTP also delivered a significantly fast protection switching time (1.975 ms), which was significantly faster than legacy Ethernet switches. These performance evaluation results prove that the proposed GOE system can be used as a cost-effective high-performance Ethernet-based VPN solution.     

High-efficiency enhancement-mode power heterojunction FET with buried p/sup +/-GaAs gate structure for low-voltage-operated mobile applications

This letter describes a successfully developed enhancement-mode double-doped AlGaAs/InGaAs/AlGaAs heterojunction FET with a buried p/sup +/-n junction gate structure for low-voltage-operated mobile applications. The buried p/sup +/-GaAs gate structure effectively reduced on-resistance (R/sub on/) and suppressed drain-current frequency dispersion for the device with high positive threshold voltage, resulting in high-efficiency characteristics under low-voltage operation. The fabricated p/sup +/-gate HJFET exhibited a low R/sub on/ of 1.4 /spl Omega//spl middot/mm with a threshold voltage of +0.4 V. Negligible frequency dispersion characteristics were obtained through pulsed current-voltage measurements for the device. Under a single 2.7-V operation, a 19.8-mm gate width device exhibited a power added efficiency of 51.9% with 26.8-dBm output power and a -40.1-dBc adjacent channel power ratio using a 1.95-GHz wideband code-division multiple-access signal.     

The relationship between deterioration and reversal of optic disc cupping in monkeys with chronic experimental high-pressure glaucoma

PURPOSE: To investigate the correlation between the deterioration in optic disc cupping during the chronic elevation of intraocular pressure (IOP) and the reversal of cupping during a subsequent reduction in IOP in experimental glaucoma. METHODS: We examined changes in the vertical and horizontal cup to disc ratios, the rim area to disc area ratio, and the cup volume to disc area ratio in 11 monkey eyes with laser-induced glaucoma using computerized stereo-image analysis. Correlations between changes in disc parameters during a spontaneous IOP reduction and changes in disc parameters during a period of chronic IOP elevation from baseline before laser exposure (baseline) to before the IOP reduction (pre-IOP reduction) and during the period from baseline to after the reduction in IOP (post-IOP reduction) were determined by linear regression analysis. RESULTS: All disc parameters improved significantly during IOP reduction and deteriorated significantly during the periods from baseline to the pre-IOP reduction and from baseline to the post-IOP reduction. The degree of reversal in disc parameters was correlated with the deterioration from baseline to the pre-IOP reduction and from baseline to the post-IOP reduction in the vertical cup to disc ratio (r = 0.68, P = 0.0218 and r = 0.97, P < 0.0001, respectively), the horizontal cup to disc ratio (r = 0.57, P = 0.0649 and r = 0.98, P < 0.0001, respectively), the rim area to disc area ratio (r = 0.68, P = 0.0227 and r = 0.98, P < 0.0001, respectively), and the cup volume to disc area ratio (r = 0.67, P = 0.0256 and r = 0.88, P = 0.0004, respectively). CONCLUSION: The degree of deterioration in cupping from baseline before the induction of glaucoma may be an important determinant of the degree of cupping reversal during subsequent reductions in IOP in primate glaucoma.     

A new shear technique: Semi Continuous Shear Flow (SCSF) in medium and ultra high molecular weight Polyhydroxybutyrate blends

In MMWT/UHMWT PHB blends (99.5/0.5), (99/1), (98/2) and (97/3) we demonstrate that by applying our new shear technique, “semi continuous shear flow”, copious fibre formation is guaranteed, irrespective of the ultra high molecular weight composition. The shishes formed via this technique are extremely stable being able to maintain their stability for at least 5–10 min. When this technique was applied to MMWT/UHMWT PHB blends of compositions (95/5), (90/10) and (85/15) disorientated fibres were observed in the flow direction. On increasing the UHMWT component, distinct unordered and intertwining of fibres resulted and with severe shearing orientation occurred, however shish formation was limited. We propose the optimum conditions for shish formation and the critical molecular weight necessary for entanglement.