A refreshable analog VLSI neural network chip with 400 neurons and40 K synapses

An on-chip learning neural network LSI circuit that can refresh the analog storage synaptic weights located on a chip is described. The chip integrates 400 neurons and 40000 synapses with a 0.8-μm double-poly double-metal CMOS technology. This device stores learned information by repeating the refresh process at 200-ms intervals     

A 336-neuron, 28 K-synapse, self-learning neural network chip withbranch-neuron-unit architecture

A self-learning neural network chip based on the branch-neuron-unit (BNU) architecture, which expands the scale of a neural network by interconnecting multiple chips without reducing performance, is described. The chip integrates 336 neurons and 28224 synapses with a 1.0-μm double-poly-Si double-metal CMOS technology. The operation speed is higher than 1×10¹² connections per second per chip. It is estimated that the network scale can be expanded to several hundred chips. In the case of 200-chip interconnections, the network will consist of 3360 neurons and 5,644,800 synapses     

Improved optical and electrical characteristics of free-standing GaN substrates by chemical polishing utilizing photo-electrochemical method

The optical and electrical properties of GaN(0001) surfaces treated by a novel chemical polishing method are described. Scanning microscopic photoluminescence images reveal that the polished GaN surface shows improved luminescence properties compared to the untreated surface. Current-voltage measurements of Schottky barriers formed using the GaN substrates show that the polished GaN surface has a lower reverse leakage current, and that the barrier height and ideality factor are improved after the polishing treatment.     

Initial Dissolution Rate of the International Simple Glass as a Function of pH and Temperature Measured Using Microchannel Flow-Through Test Method

International simple glass (ISG) is a six-component alumino-borosilicate glass developed as a reference benchmark glass for six nations collaborating study on high-level nuclear waste glass dissolution/corrosion mechanism. In this study, aqueous dissolution tests were performed for the ISG using microchannel flow-through (MCFT) method to evaluate the initial dissolution rate of glass matrix, r₀, precisely and systematically as a function of solution pH and temperature. The test results indicated that the r₀ shows a “V-shaped” pH dependence with a bottom at around pH4 at each temperature. Compared with Japanese reference glass of P0798, for which the r₀ showed a “U-shaped” pH dependence with a bottom at around pH6 in our previous study, the ISG shows the higher dissolution rate at basic pH, and lower dissolution rate at neutral to acidic pH. The results also indicated that the r₀ increases with temperature according to an Arrhenius law, and the apparent activation energy evaluated from Arrhenius relation is 62–77 [kJ/mol] at any pH from 3 to 10, which suggests the initial dissolution of ISG proceeds controlled by a surface-reaction mechanism in this pH range.     

Evaluation of melting point of UO2 by molecular dynamics simulation

The melting point of UO₂ has been evaluated by molecular dynamics simulation (MD) in terms of interatomic potential, pressure and Schottky defect concentration. The Born-Mayer-Huggins potentials with or without a Morse potential were explored in the present study. Two-phase simulation whose supercell at the initial state consisted of solid and liquid phases gave the melting point comparable to the experimental data using the potential proposed by Yakub. The heat of fusion was determined by the difference in enthalpy at the melting point. In addition, MD calculations showed that the melting point increased with pressure applied to the system. Thus, the Clausius-Clapeyron equation was verified. Furthermore, MD calculations clarified that an addition of Schottky defects, which generated the local disorder in the UO₂ crystal, lowered the melting point.     

Characteristic of local boiling heat transfer of ammonia and ammonia / water binary mixture on the plate type evaporator

Power generation using small temperature difference such as ocean thermal energy conversion (OTEC) and discharged thermal energy conversion (DTEC) is expected to be the countermeasures against global warming problem. As ammonia and ammonia/water are used in evaporators for OTEC and DTEC as working fluids, the research of their local boiling heat transfer is important for improvement of the power generation efficiency. Measurements of local boiling heat transfer coefficients were performed for ammonia /water mixture (z = 0.9−1) on a vertical flat plate heat exchanger in a range of mass flux (7.5–15 kg/m² s), heat flux (15–23 kW/m²), and pressure (0.7–0.9 MPa). The result shows that in the case of ammonia /water mixture, the local heat transfer coefficients increase with an increase of mass flux and composition of ammonia, and decrease with an increase of heat flux.     

Granulocyte-colony stimulating factor-induced proliferation of primary adult T-cell leukaemia cells

Granulocyte-colony stimulating factor (G-CSF) is known to induce proliferation and differentiation of granulocyte progenitors, and is widely used to treat neutropenia induced by intensive chemotherapy for malignant lymphoma or adult T-cell leukaemia/lymphoma (ATL). G-CSF is thought not to stimulate malignant lymphoid cells. In the present study we examined the ability of G-CSF to induce in vitro growth of primary ATL cells from 14 patients (nine acute-type, two chronic-type and three lymphoma-type), and we analysed the in vivo counts of ATL cells in patients who received G-CSF for neutropenia. FACS analysis using phycoerythrin-labelled recombinant G-CSF demonstrated that ATL cells from 11/14 patients express some G-CSF receptor (G-CSFR), with a range between 5.4% and 87.3%. Cells expressing G-CSFR also expressed CD4. Reverse polymerase chain reaction (PCR) analysis demonstrated expression of G-CSFR messenger RNA in G-CSFR expressing cells. Leukaemic cells derived from seven (four acute-type, one chronic-type and two lymphoma-type) of the 14 patients proliferated in vitro in response to G-CSF, as measured by [3H]thymidine incorporation; maximum responses were at G-CSF concentrations of 10-100 ng/ml. Nine of 14 patients receiving rG-CSF for neutropenia were analysed retrospectively for ATL cell numbers. Four patients whose primary tumour cells proliferated in response to rG-CSF in vitro showed a significant increase in ATL cell count after administration of rG-CSF (P = 0.038), whereas five patients whose leukaemic cells did not proliferate in vitro showed no significant increase in ATL cell count. G-CSF can stimulate proliferation of ATL cells which may complicate therapy for this disease.