Development of a novel image intensifier of an amplifiedmetal-oxide semiconductor imager overlaid with electron-bombardedamorphous silicon

We developed a novel image intensifier (II) of an amplified metal-oxide-semiconductor (MOS) imager (AMI) overlaid with electron-bombarded (EB) amorphous silicon (a-Si). The electron bombardment gain (EB gain) was 1500 at an accelerating voltage of 10 kV. Since the multiplication process was free from a phosphorescent screen and a coupling fiber plate as in the conventional II, the resolution was high and the picture quality was good and free from granularity noises, white spots, lag and sticking. As for fatigue of X-ray irradiation, the contrasts of a vertical stripe (Smear) are not detectable and damaged areas in AMI are weak whereas both of those in charge-coupled devices (CCDs) are strong     

Color registration error reduction method compensating the influence of belt thickness variation in electrophotographic process

This paper proposes a new belt drive control method for reducing a belt velocity-fluctuation that is caused by a belt thickness-variation in the circumferential direction. A belt driving system performs feedback control with a rotary encoder-output mounted on a driven roller. This proposed method correct the reference value of the feedback control for the purpose of the belt velocity regulation. The correction includes two steps. The first step acquires the encoder-output of the driven roller and calculates the rotational angular velocity-fluctuation with one cycle of the belt rotation. The second step converts from the velocity-fluctuation to the correction value of the feedback reference. The correction value cancels a detection error of the driven roller caused by the belt thickness-variation. After these steps, the belt driving system controls the belt velocity as compensating the belt velocity-fluctuation. Experimental result showed the significant fluctuation reduction on a typical tandem-engine printer.     

High-temperature oxidation of Al-deposited stainless-steel foils

The oxidation resistance of Al-deposited Fe–Cr–Al foils containing small amounts of La and Ce was assessed by a cyclic oxidation test with temperature varying between room temperature and 1323 K to 1423 K in static air. (1) The Al content of Fe–Cr–Al–La, Ce foils can be increased by depositing an Al layer from the vapor phase. The deposition of a 1-m-thick Al layer on both sides of the 50-m-thick foil is equivalent to a 1.5 mass% increase in the Al content. The deposited Al diffuses into the foil during heat treatment. The uniform distribution of Al is obtained by heating at 1273 K for 18 ks. (2) After the initial transition stage the oxidation follows the parabolic law until breakaway sets in. The scale consists mainly of -Al₂O₃ during the parabolic period. (3) The increase in the Al content by more than 5 mass% by the Al-deposition remarkably improves high-temperature oxidation resistance (smaller parabolic rate constant and longer protection time). (4) The Al-deposited foils have better oxidation resistance than the conventional foils with the same contents of Al and rare-earth elements. This is attributable to the different nature of the initially formed oxide on the Al-deposited foil. (5) The so-called rare-earth element effect was also observed for the Al-deposited foils. Predominant diffusion of oxygen through the Al₂O₃ scale and vacancy-sink mechanism are applicable to the present results.     

Mating-induced mating-type cassette conversion in Saccharomyces cerevisiae

We have previously reported that the HMRa-bearing restriction fragment of a rho degrees sir4-11 strain (HMLalpha-MATalpha-HMRa), which acts as an alpha-mater because of being rho degrees , changes its electrophoretic mobility when the strain mates with a certain group of a-mating strains (HMLalpha-MATa-HMRa). In this study, we found that the sir4-11 strain being rho degrees was not essential for this phenomenon and also that the altered form of the fragment contained HMRalpha in place of HMRa. Furthermore, we observed conversion of HMLa to HMLalpha in the cross in which a sir4-11 HMLa-MATalpha-HMRalpha strain was mated with a representative of the above-mentioned a-mating strain. In addition, when this a-mating strain was mated with a SIR(+) HMLalpha-MATa-HMRalpha strain, the resultant diploid was found to be HMLalpha/HMLalpha MATa/MATalphaHMRa/HMRalpha, indicating that conversion of MATa to MATalpha had taken place in the course of mating. From all these observations, we conclude that there is a group of S. cerevisiae strains that carries factor(s) that induces conversion of a mating-type cassette of the mating partner to alpha mating-type cassette and that this mating type cassette conversion takes place in all three mating type loci, HML, MAT and HMR, if the loci are in the non-silenced condition.     

Increased energy absorption in ZnO arrester elements throughcontrol of electrode edge margin

ZnO nonlinear dielectric has a small temperature coefficient of conductivity up to about 550 C, and above 550 C the temperature coefficient of conductivity becomes substantially positive, which tends to result in thermal runaway through condensation of the current density into filaments which “melt” their way through the ceramic. Thus to obtain maximum energy absorption in a ZnO element, it is important to avoid hot spots so that the element will heat quite uniformly to its maximum stable operating temperature in the range of 550 C. The current density at the electrode edge is enhanced by spreading of the current into the ZnO at radii larger than the electrode. This causes an enhanced temperature at the electrode edge which results in the “melting punctures” commonly observed. Using transient, nonlinear finite element analysis with coupled thermal and electric fields, the authors have quantified the temperature enhancement as a function of edge margin and optimized the electrode topology     

Experimental evaluation of combined effect of coherent RAKEcombining and SIR-based fast transmit power control for reverse link ofDS-CDMA mobile radio

The combined effect of coherent RAKE combining using the weighted multislot averaging (WMSA) channel estimation filter and closed-loop fast transmit power control (TPC) in the 4.096 Mchip/s direct sequence code division multiple access (DS-CDMA) mobile radio reverse link is experimentally evaluated. The WMSA channel estimation filter utilizes periodically transmitted pilot symbols (four pilot symbols are time-multiplexed in each 40-symbol time slot). Its observation period is extended to 2-K slots in order to improve the accuracy of the channel estimation. The fast TPC is based on the measurement of signal-to-interference plus background noise ratio (SIR) using pilot symbols. Laboratory experiments show that the use of the K=2 WMSA channel estimation filter reduces the required E_b/I₀ at the average BER of 10^-3 by approximately 0.5 dB compared to use of the linear interpolation filter, and that the required E_b/I₀ is minimized when the SIR measurement interval is M=10 symbols (one slot TPC delay). It was also clarified that SIR-based TPC works satisfactorily when two users with different information data rates, i.e., SF, independently employ fast TPC. Field experimental results obtained in an area nearby Tokyo showed that the average BER of 10^-3 is achieved at the target E_b/I₀ per antenna of approximately 2.5 dB by using four-finger branch RAKE and two-branch antenna diversity. Although the target E_b/I₀ to achieve same BER, when there is one interfering user with a fourfold greater transmit power than that of the desired user that independently employs fast TPC, is almost the same as that in the single-user case, the mobile transmit power is increased by 1.0-2.0 dB due to the increased MAI. These results indicate that the combination of coherent RAKE combining and fast TPC works well in practical multipath fading channels     

Effects of coal rank and reaction conditions upon coprocessing coal with waste tyre

It is well known that the amount of waste tyre increases every year, and a numerous amount of waste tyre is landfilled or dumped all over the world, which causes environmental problems, such as destruction of natural places and the risk of fires. Coprocessing waste tyre and coal is considered as one of the effective processing methods of both materials. Upon coprocessing lower rank coal (Wyoming, C; 68%) with waste tyre, the synergistic effects to upgrading, such as the increase of oil yield and the decrease of residue yield, were appeared. However, the synergistic effects were not observed on coprocessing two kinds of higher rank coals with waste tyre. The reactions of coal with benzophenone were carried out to discuss the hydrogen donatability of coal. Conversion of benzophenone to diphenylmethane on the reaction with Wyoming coal was higher than those of higher rank coals. Accordingly, it was considered that the synergistic effects to upgrading upon coprocessing Wyoming coal with waste tyre were obtained owing to the enhancement of stabilization of radicals from tyre and Wyoming coal through the hydrogen donation from both tyre and Wyoming coal. The effects of reaction temperature and the amount of solvent upon coprocessing Wyoming coal with waste tyre were also discussed in this study.     

Experiments on pilot symbol-assisted coherent multistageinterference canceller for DS-CDMA mobile radio

A three-stage coherent multistage interference canceller (COMSIC) employing pilot symbol-assisted (PSA) channel estimation for replica generation of multiple access interference (MAI) is implemented and its performance in the presence of frequency selective multipath fading is experimentally evaluated by a multipath fading simulator. A fast transmission power control (TPC) method suitable for COMSIC is also proposed, in which the signal-to-interference plus background noise power ratio (SIR) at the matched filter (MF) based RAKE receiver is measured to achieve a short TPC delay and the target signal-to-interference ratio value is compensated by an outer loop so that the measured block error rate (BLER) is equal to the prescribed target value. The experimental results show that as expected the COMSIC satisfactorily reduces the MAI even when the number of active users is equal to the spreading factor in a multipath fading environment, and thus, improves the bit error rate (BER) performance in a multiuser environment. The results also show that the proposed fast TPC method with a two-slot delay associated with COMSIC works satisfactorily and the combination of COMSIC and fast TPC significantly decreases the transmission power of a mobile station (required transmission power of a mobile station with COMSIC at the average BER of 10^-3 is decreased by approximately 2.0 (3.0) dB compared with the MF-based RAKE receiver with (without) antenna diversity reception). This extends the cell coverage, battery life, and increases the system capacity in the reverse link