Measurements of distribution of self-bias potential on an RF-plane electrode in plasma etching devices

The self-bias potential (V_dc) induced on an RF-powdered electrode (153 mm Ø) in a plasma is measured using electrical probes which are buried in, de-insulated from, and RF-connected to the electrode. The configuration of the probes allows to study the distribution of V_dc discretely on the electrode. The potential is homogeneous in the absence of external magnetic field. In the presence of a homogeneous magnetic field parallel to the electrode, it is reduced and a monotonous gradient takes place in its distribution due to the plasma shift induced by E × B drift. When the magnetic field is rotated along the axis of the RF-electrode at a frequency less than 50 Hz, the distribution, which is almost identical to the one in a static field, rotates with the magnetic field. On the coordinate system rotating with the magnetic field, the probes are regarded to be rotating. The potential distribution is obtained as a continuous function of the azimuthal angle. Thus the rotation of the field provides information for the experimental interpolation.     

The Gmicro/500 superscalar microprocessor with branch buffers

The Gmicro/500, which features a RISC-like dual-pipeline structure for high-speed execution of basic instructions and represents a significant advance for the TRON architecture, is presented. Upwardly-object-compatible with earlier members of the Gmicro series, this microprocessor uses resident dedicated branch buffers to greatly enhance branch instruction execution speed. Its microprograms simultaneously use dual execution blocks to execute high-level language instructions effectively. Fabricated with a 0.6-μm CMOS technology on a 10.9-mm×16-mm die, the chip operates at 50/66 MHz and achieves a processing rate of 100/132 MIPS     

Plan for first phase of safety demonstration tests of the High Temperature Engineering Test Reactor (HTTR)

Safety demonstration tests using the High Temperature Engineering Test Reactor (HTTR) will be conducted for the purpose of demonstrating inherent safety features of High Temperature Gas-cooled Reactors (HTGRs) as well as providing the core and plant transient data for validation of HTGR safety analysis codes. The first phase safety demonstration test items include the reactivity insertion test and the coolant flow reduction test. In the reactivity insertion test, which is the control rod withdrawal test, one pair out of 16 pairs of control rods is withdrawn, simulating a reactivity insertion event. The coolant flow reduction test consists of the partial loss of coolant flow test and the gas circulators trip test. In the partial loss of coolant flow test, primary coolant flow rate is slightly reduced by control system. In the gas circulators trip test one and two out of three gas circulators are run down, simulating coolant flow reduction events. The gas circulators trip tests, in which position of control rods are kept unchanged, are simulation tests of anticipated transients without scram (ATWS).     

Experimental examination of the characteristics of bright-field scanning confocal electron microscopy images

We experimentally examined the characteristics of bright-field (BF) scanning confocal electron microscopy (SCEM) images by changing the observation conditions and comparing the images with those obtained by BF transmission electron microscopy (TEM) and BF scanning TEM (STEM) modes. The observation of 5-nm-diameter Au nanoparticles demonstrated that BF-SCEM produces object elongation of more than 2000?nm along the optical axis, as do BF-TEM and BF-STEM. We demonstrated the relationship between elongation length and geometric effects such as convergence and collection angles of a probe and the lateral size of an object; the relationship is consistent with previous theoretical prediction. Further, we observed interesting features that are seen only in the BF-SCEM images; the film contrast was strongly enhanced, compared with that of BF-STEM. In addition, a bright contrast appeared around the object position in the elongated images. Using this characteristic, we could determine the object position and structure.     

Three replacement models with two kinds of damage

This paper proposes three replacement policies for a modified cumulative damage model. An item receives shocks and suffers two kinds of damage: one is produced by shocks and the other increases with time at constant rate a. It fails only when the total damage exceeds a failure level K at some shock and is replaced before failure at time T, at shock N, or at damage k. The expected cost rates of three replacement policies are obtained. When shocks occur in a Poisson process, optimal T^*, N^* and k^* which minimize them are computed numerically. Finally, two extended cases where a is a function of time and K is a random variable are also considered.     

Reliability of rare-earth-doped fluoride fibers for optical fiberamplifier application

We have clarified the strength and estimated lifetime of fluoride fibers for optical amplifier use. We fabricated a UV-curable epoxy-acrylate coated fluoride fiber with a strength of 542 MPa. We estimated the lifetime of the fluoride fiber to be longer than 25 years at 80°C and 50% RH     

A rod matrix compensator for small-field intensity modulated radiation therapy: a preliminary phantom study

A compensator made of a tungsten-based rod matrix has been proposed for small-field intensity modulated radiation therapy. The compensator was attached to a 6 MV linac gantry head. The proposed compensator could modulate the X-ray intensity with a step of 10% and a minimum transmission of 2.5%.     

Insolation forecasting by a multi-stage neural network

A single-stage neural network has been proposed to forecast next day insolation. In this paper, a multi-stage neural network is developed to reduce forecasting error further. A first-stage neural network forecasts average atmospheric pressure for the next day from atmospheric pressure data of the previous day. A second-stage neural network forecasts insolation level for the next day from the average atmospheric pressure and weather data of the previous day. A third-stage neural network forecasts next day insolation from the insolation level and weather data of the previous day. Meteorological data of Omaezaki, Shizuoka at April 1994 were chosen as input data. The insolation values forecasted by the multi-stage and the single-stage neural networks are compared with the measurement values. The results show that the forecasting error is reduced to 24% (by the multi-stage) from 33% (by the single-stage). © 1998 Scripta Technica, Electr Eng Jpn, 125(4): 26–33, 1998     

A 98 mm2 die size 3.3-V 64-Mb flash memory with FN-NORtype four-level cell

In order to realize high-capacity and low-cost flash memory, we have developed a 64-Mb flash memory with multilevel cell operation scheme. The 64-Mb flash memory has been achieved in a 98 mm² die size by using four-level per cell operation scheme, NOR type cell array, and 0.4-μm CMOS technology. Using an FN type program/erase cell allows a single 3.3 V supply voltage. In order to establish fast programming operation using Fowler-Nordheim (FN)-NOR type memory cell, we have developed a highly parallel multilevel programming technology. The drain voltage controlled multilevel programming (DCMP) scheme, the parallel multilevel verify (PMV) circuit, and the compact multilevel sense-amplifier (CMS) have been implemented to achieve 128 b parallel programming and 6.3 μs/Byte programming speed