High efficiency, wide dynamic range variable gain and poweramplifier MMICs for wideband CDMA handsets

A linearized variable gain amplifier (VGA) and a two-stage power amplifier (PA) MMIC were developed for 1.95-GHz wideband CDMA (W-CDMA) handsets application. A complete PA block with power control ability was obtained by cascading the VGA with the PA. The linearized VGA consists of a predistorter (PD) integrated with a conventional VGA, performing dual function for achieving high linearity power control, as well as reducing output distortion level of the following PA. With the use of predistortion, the P_out and power added efficiency (PAE) of the PA block improved from 27.5 dBm and 39.8% to 28.5 dBm and 44.8%, respectively, measured at -35 dBc adjacent channel leakage power ratio (ACPR). Under power control operation, the control range of the PA block increased from 23.6 dB to 31.2 db, and ACPR reduction of over 10 dB was achieved with the use of linearized VGA     

Effects of arc current and electrode size on electrode erosion in ac plasma torches

Heavy erosion of the electrode is a problem in using ac plasma torches. In a series of our studies, the effects of electrode stem size (diameter and length) and tip shape on the electrode erosion were clarified at a low current of 200 A. In this paper, on the basis of the 200-A data, in order to reduce the electrode erosion with the current increased, the effects of current and electrode size on electrode erosion were clarified experimentally and analytically between 100 and 550 A. The electrode used was of solid type and the material was tungsten containing 2 wt% of lanthanum oxide. The plasma gas was argon. Main results are as follows. (1) As the current increased, the electrode erosion increased linearly. In the case of thin electrodes (8 mm ø), between 450 and 550 A, the electrode tip was molten partially and the electrode erosion increased rapidly over 5 mg/h. However, for thick electrodes (13 mm ø), the electrode erosion did not increase rapidly. (2) The temperature distribution along the electrode axis was calculated. As a result, a good correlation was obtained between the calculated temperature of electrode tip and the measured electrode erosion. As the tip temperature decreased to 3000 K (cf. tungsten melting point: 3660 K), the electrode erosion decreased below 5 mg/h of the linearly increasing range.     

A high-density NAND EEPROM with block-page programming formicrocomputer applications

A high-density, 5-V-only, 4-Mb CMOS EEPROM with a NAND-structured cell using Fowler-Nordheim tunneling for programming is discussed. The block-page mode is utilized for high-speed programming and easy microprocessor interface. On-chip test circuits for shortening test time and for evaluating cell characteristics yield highly reliable EEPROMs. The NAND EEPROM has many applications for microcomputer systems that require small size and large nonvolatile storage systems with low power consumption     

High-Speed X-Cut Thin-Sheet LiNbO3 Optical Modulator With Folded Structure

We propose a small-footprint X-cut thin-sheet lithium niobate optical modulator with high-speed and low-driving-voltage characteristics. Since an optical waveguide is folded by a mirror placed at one edge of the modulation chip, the chip can be shortened by about half. In addition, a wide modulation bandwidth can be achieved, because the path-length difference between the optical waveguide and the coplanar-waveguide (CPW) electrode is decreased to as short as possible by placing the CPW electrode as far as possible along the optical waveguide in the folded portion, and the microwave effective index is set to realize effective velocity matching between the lightwave and the microwave. A small footprint of 1.78 times 29 mm, a low half-wave voltage of 2.0 V at dc, and a 3-dBe modulation bandwidth of 20 GHz were obtained.     

CoCl(2) inhibits neural differentiation of retinoic acid-treated embryoid bodies

The effects of CoCl(2) on retinoic acid (RA)-treated embryoid bodies (EBs) were investigated. Four-day EBs were treated with 5x10(-6) M of RA for 4 d, then subjected to attached culturing for 7 d in the presence of CoCl(2) at 0, 20, and 100 microM. Differentiation into MAP2- and GFAP-immunopositive cells was inhibited by CoCl(2) in a dose-dependent manner. Next, RA-treated EBs were dissociated into single cells and cultured for 7 d at an initial cell density of 1x10(3)/cm(2). The number of cells increased in a CoCl(2)-dose dependent fashion. In cultures with 100 microM of CoCl(2), more than 90% of the cells were immunopositive for nestin and nestin-immunopositive cells formed clusters, while there were few cells immunopositive for MAP2 or GFAP. These results suggest that CoCl(2) inhibits neural differentiation of RA-treated EB cells and promotes the proliferation of nestin-immunopositive cells, i.e., embryonic stem (ES)-derived neural stem-like cells.     

Shear properties of metal-free wooden load-bearing walls using plywood jointed with a combination of adhesive tape and wood dowels

In this study, the potential of wood-only (metal-free) load-bearing walls was proposed and tested based on the idea of using the same type of material throughout wherever possible while improving basic properties such as strength, sound insulation, and heat insulation. Specifically, a technique was tested of combining pressure sensitive adhesive tape and wood dowels in place of nails for load-bearing structures with panel reinforcement represented by wood-frame construction. For this paper, its strength was evaluated by conducting in-plane shear tests, which revealed that the initial rigidity and maximum load of the proposed test specimens were greater than that of specimens using nails for jointing. However, the shear load factor, which is calculated based on some strength parameters and which forms the foundation of housing strength design, was slightly lower than that of the nail-jointed specimen. This was because there was a large decline in post-collapse resistance and a lower calculated absorbed energy caused by brittleness. The early detachment of panels was also revealed as a problem in the tests.     

Dissimilarity scaling and INDSCAL analysis in the study of flavour differences between normal pHu and DFD beef

Overall dissimilarity measurement of paired stimuli followed by Individual Differences Scaling (INDSCAL) analysis was used to study flavour perception in a set of beef extracts. The experiment was designed to determine whether pH contributed to flavour difference between beef of “normal” ultimate pH (pHu5.8) and “dark-cutting” (DFD) beef (pHu6.2). Assessors distinguished the flavour of “normal” pHu and DFD beef both by a combination of pH and titratable acidity, and a second dimension independent of pH. The chemicals added to adjust pH independently of the original muscle composition contributed a third flavour dimension. Substantial assessor variation was observed in the relative weight given to the three flavour dimensions, and this is discussed in relation to the task of judging overall dissimilarity.     

Purification and characterization of rice alpha-glucosidase, a key enzyme for alcohol fermentation of rice polish

Alpha-glucosidase, a key enzyme for nuka-sake brewing, was purified from Oryza sativa cv. Yamadanishiki, which is widely used for sake brewing. The molecular weight of the purified enzyme was 95 kDa. The optimum pH and temperature were 4.5 and 55 degrees C, respectively. The substrate specificity differed from that of Oryza sativa cv. Shinsetsu, which is a variety of rice consumed as a cereal. The extraction of alpha-glucosidase from the rice was stimulated by lactic acid, which suggests that lactic acid plays an important role not only in preventing bacterial contamination, but also in stimulating the parallel fermentation that occurs in nuka-sake brewing.