Interface reactions between titanium thin films and (1¯1 2) sapphire substrates

We have studied the reactivity of Ti with the R-plane (1ˉ1 2) of sapphire from room temperature to 1250 °C by X-ray photoemission spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Rutherford backscattering spectroscopy (RBS). The combination of these techniques allowed the interface reactions to be studied from the monolayer regime up to the bulk regime. XPS showed that at room temperature, monolayer coverages of Ti reduced the sapphire surface to form Ti-O and Ti-Al bonds. TEM, XRD, and RBS showed that annealing of room-temperature deposited Ti resulted in an interfacial region consisting of two layers, a Ti₃Al[O] layer adjacent to the sapphire and a Ti_0.67 [O_0.33] layer at the free surface. The growth of the Ti₃Al[O] layer had an activation energy of 103.4±25 kJ deg-mole. The nature of the interfacial reaction between Ti and sapphire was similar for Ti coverages from the monolayer to the bulk regime.     

Possible participation of cyclooxygenase-2 in the recurrence of allergic inflammation in rats

The possible involvement of purines and/or nitric oxide (NO) in the gamma-aminobutyric acid (GABA)A receptor-mediated effects on the spontaneous activity of isolated preparations from longitudinal and circular muscles of cat terminal ileum was investigated. GABA had biphasic effects, which were neurogenic and muscarinic. ATP and adenosine dose dependently inhibited the activity of the muscles. A contractile response evoked by the nucleotide only was also observed. The effects of the purines were equipotent and resistant to Nomega-nitro-L-arginine (L-NNA), tetrodotoxin and to desensitization by alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-meATP), except for the contractile effect of ATP, which was abolished by alpha,beta-meATP. Pretreatment of the preparations with ATP or adenosine produced: (i) desensitization to the effects of the respective purinoceptor agonist only; and (ii) suppression of the GABA-induced responses of longitudinal and circular muscles. Hemoglobin and L-NNA greatly reduced or completely blocked the GABA(A)-induced relaxation and decreased the GABA(A)-induced contraction. Our results indicate that purines and NO, to a different extent, mediate the relaxant phase of the GABA effects in both layers. Interactions between muscarinic cholinoceptors and GABA-nitrergic pathway and a concomitant activation of postjunctional P1 and P2y purinoceptors are suggested to explain the prejunctional biphasic effects of GABA.     

Emergence and stability of key currency in artificial international trade

In this research, we tackled the emergence and stability of key currency when economic strength countries was equal. We propose an artificial international market model with currency credibility as the standard selected for payment. We constructed multiple markets based on the X-Economy System. Through simulations, we found the possibility that key currency could emerge in a symmetric situation, and market and the specialization of production could be stabilized by foreign exchange trade.     

Cooperative control of multiple neural networks for an indoor blimp robot

We report on the cooperative control of multiple neural networks for an indoor blimp robot. In our research group, the indoor blimp robot has been studied to achieve various flying robot applications. The objective of this article is to propose a robust controller that can adapt to mechanical accidents such as the breakdown of propellers. In our proposed method, each propeller thrust is independently calculated by a small neural network. We confirm the advantage of the proposed method against the control by a single large neural network. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Magnetic field characteristics of the low-beta quadrupole magnets, MQXA, for LHC

As a part of the collaboration program between CERN and KEK for the LHC, KEK has developed a superconducting low-beta quadrupole magnet, MQXA. KEK will supply 18 MQXA magnets, and 16 magnets will be installed in total in the four interaction regions. The cold tests of 13 magnets have been completed. Systematic field measurements were performed on these magnets, and these 13 magnets had satisfactory field quality for the requirement of beam optics. This paper describes the magnetic field behavior of the 13 MQXA magnets from the viewpoint of accelerator operation.     

A high performance pMOSFET with two-step recessed SiGe-S/D structure for 32 nm node and beyond

A novel SiGe-S/D structure for high performance pMOSFET called two-step recessed SiGe-source/drain (S/D) is developed with careful optimization of recessed SiGe-S/D structure. With this method, hole mobility, short channel effect and S/D resistance in pMOSFET are improved compared with conventional recessed SiGe-S/D structure. To enhance device performance such as drain current drivability, SiGe region has to be closer to channel region. Then, conventional deep SiGe-S/D region with carefully optimized shallow SiGe SDE region showed additional device performance improvement without SCE degradation. As a result, high performance 24 nm gate length pMOSFET was demonstrated with drive current of 451 μA/μm at V_dd of 0.9 V and I_off of 100 nA/μm (552 μA/μm at V_dd of 1.0 V). Furthermore, by combining with V_dd scaling, we indicate the extendability of two-step recessed SiGe-S/D structure down to 15 nm node generation.     

A Si bipolar 28-GHz dynamic frequency divider

A dynamic frequency divider applying the regenerative frequency division principle has been developed. A spiral inductor on the silicon substrate used as a load is characterized, and an improved one-port model with the substrate resistance is discussed. A 1/16 frequency divider was implemented with a silicon bipolar technology with a cutoff frequency of 40 GHz. The operation frequency range was 11.8-28.1 GHz, covering the Ka band (18-26.5 GHz). The inductive load has improved the maximum operation frequency by 7%, compared with a conventional circuit. Complemented with a 21-GHz static frequency divider previously reported by the authors, the whole microwave frequency range up to 26.5 GHz has been completely covered with the silicon bipolar technology. The maximum operation frequency of a silicon MMIC has been extended to the millimeter-wave frequency region for the first time     

Left ventricular rupture following mitral valve replacement

Rupture of the posterior wall of the left ventricle is an unusual but often lethal complication following mitral valve replacement. The incidence is about 1% of MVRs. Most of the ruptures are attributed either to technical maneuvers in the operation or to stretch injury produced by removal of the mural leaflet of the mitral valve. Surgical repair of the rupture requires the cardiopulmonary bypass, and it seems to be suited that we select extracardiac approach to type 2 or 3 rupture and intracardiac approach to type 1 rupture. Preventive measures include the modifications in operative techniques, reduction of pre and afterload of the left ventricle, and retention of posterior mitral leaflet.     

An experimental 4-Mbit CMOS EEPROM with a NAND-structured cell

A 5-V-only high-density (512 K*8 bit) electrically erasable and programmable read-only memory (EEPROM) has been designed and fabricated by using a NAND-structured cell with 1.0- mu m design rules. The average cell area per bit is 12.9 mu m/sup 2/. Block erasing, successive programming, and random reading are achieved using a newly developed NAND-cell control circuit. Typical erasing time is 1.0 ms and page-programming time is 4.0 ms, equivalent to 1.0 mu s/bit. A dynamic sensing system is introduced to sense the small cell current. Typical read access time is 1.6 mu s. The die size is 10.7*15.3 mm/sup 2/.<>