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The photoelectron momentum microscope (PMM) in operation at BL6U, an undulator-based soft x-ray beamline at the UVSOR Synchrotron Facility, offers a new approach for μm-scale momentum-resolved photoelectron spectroscopy (MRPES). A key feature of the PMM is that it can very effectively reduce radiation-induced damage by directly projecting a single photoelectron constant energy contour in reciprocal space with a radius of a few Å−1 or real space with a radius of a few 100 μm onto a two-dimensional detector. This approach was applied to three-dimensional valence band structure E(k) and E(r) measurements ("stereography") as functions of photon energy (hν), its polarization (e), detection position (r), and temperature (T). In this study, we described some examples of possible measurement techniques using a soft x-ray PMM. We successfully applied this stereography technique to μm-scale MRPES to selectively visualize the single-domain band structure of twinned face-centered-cubic Ir thin films grown on Al2O3(0001) substrates. The photon energy dependence of the photoelectron intensity on the Au(111) surface state was measured in detail within the bulk Fermi surface. By changing the temperature of 1T-TaS2, we clarified the variations in the valence band dispersion associated with chiral charge-density-wave phase transitions. Finally, PMMs for valence band stereography with various electron analyzers were compared, and the advantages of each were discussed. [ABSTRACT FROM AUTHOR]

Gate oxides on low-dose separation by implanted oxygen (SIMOX) substrates, produced by the ITOX process, were examined.

The formation of basal plane stacking faults in heavily nitrogen-doped 4H-SiC crystals was theoretically investigated. A novel theoretical model based on the so-called quantum well action mechanism was proposed; the model considers several factors, which were overlooked in a previously proposed model, and provides a detailed explanation of the annealing-induced formation of double layer Shockley-type stacking faults in heavily nitrogen-doped 4H-SiC crystals. We further revised the model to consider the carrier distribution in the depletion regions adjacent to the stacking fault and successfully explained the shrinkage of stacking faults during annealing at even higher temperatures. The model also succeeded in accounting for the aluminum co-doping effect in heavily nitrogen-doped 4H-SiC crystals, in that the stacking fault formation is suppressed when aluminum acceptors are co-doped in the crystals. [ABSTRACT FROM AUTHOR]

Photoelectron spectroscopy resolved in three-dimensional momentum space with a microscopic field of view is realized by combining a so-called Momentum Microscope with a soft X-ray synchrotron radiation source. A new experimental station for momentum-resolved photoelectron micro-spectroscopy and spectro-microscopy has been built at BL6U, an undulator-based soft X-ray beamline of the UVSOR synchrotron facility. This experimental station specializes in characterizing the electronic structure of surface atomic sites, thin films, molecular adsorbates, and bulk crystals. The instrument details are described along with possible measurement techniques. [ABSTRACT FROM AUTHOR]

The optimized incidence angle and magnetic field direction geometry of an InAs terahertz radiation emitter irradiated with femtosecond laser pulses in a magnetic field is reported. The optimum geometric layout is the magnetic field direction parallel to the semiconductor surface and at an incidence angle that is slightly larger than the Brewster angle. Additionally, we also observed a center frequency shift of terahertz radiation spectrum by changing the incidence angle of the excitation laser. [C] 2001 Optical Society of America OCIS codes: 140.0140, 140.3070.

Abstract: The use of anhydrous phenylglyoxal provides a solution to the problem of low reactivity in the asymmetric intramolecular Cannizzaro reaction with alcohols. Double asymmetric induction was achieved in the reaction of anhydrous phenylglyoxal with d-(+)-menthol promoted by a (S,S)-t-BuBox·copper(II) hexafluoroantimonate complex. [Copyright &y& Elsevier]

A flow-injection biosensor system with an on-line microdialysis sampling is proposed for the simultaneous assay of l-lactate and pyruvate in serum and rat brain. The dialysate collected in the sample loop by perfusing Ringer’s solution through the microdialysis probe is automatically injected into the flow-injection line with a dual enzyme electrode arranged in parallel for the flow direction. The dual enzyme electrode is constructed by hybridizing a poly(1,2-diaminobenzene) film to two sensing parts, which respond selectively to l-lactate and pyruvate, respectively, without any cross-reactivity. Both the sensing parts respond linearly to the concentrations of both analytes between 0.01 and 5 mM, without any interference from oxidizable species and low-molecular weight proteins present in the dialysate. The proposed flow-injection analysis (FIA) method can be successfully applied to the simultaneous in vitro and in vivo assays of both analytes in serum and rat brain, respectively. The system can be automatically processed at an analytical speed of 19 dialysates h-1 over a period of 5 h. [Copyright &y& Elsevier]

Abstract: The effect of down-regulation of Mcl-1 expression by small interfering RNA (siRNA) against the canine Mcl-1 gene on apoptosis was investigated by transfecting CF33 (canine mammary gland tumor cell line) with siRNA using cationic liposomes. The siRNA against canine Mcl-1 increased the rate of apoptotic cells and decreased the numbers of viable cells. Further, sequence-specific down-regulation of Mcl-1 expression was measured by real time-PCR and Western blot analysis. The siRNA directed against the Mcl-1 gene reduced both the mRNA and protein expression in the CF33. Our study suggests the importance of Mcl-1 in canine mammary tumors for inducing apoptosis and reinforces using Mcl-1 as a putative therapeutic target in canine mammary gland tumor. [Copyright &y& Elsevier]

We report on the terahertz radiation from femtosecond-laser-irradiated indium arsenide in high magnetic fields up to 14 T. It is found that the radiation power exhibits anomalous magnetic-field dependence, including saturation, decrease, and recovery up to 14 T. Moreover, the radiation spectrum possesses a clear periodic structure over 6 T. [ABSTRACT FROM AUTHOR]

We produce patterns on minute and curved surfaces of optical fibers, and develop a processing technology for fabricating sensors, antennas, electrical circuits, and other devices on such patterned surfaces by metallization. A three-dimensional processing technology can be used to fabricate a spiral coil on the surface of cylindrical quartz materials, and then the microcoils can also be applied to capillaries of micro-fluid devices, as well as to receiver coils connected to a catheter and an endoscope of nuclear magnetic resonance imaging (MRI) systems used in imaging blood vessels. To create a spiral line pattern with a small linewidth on a full-circumference surface of an optical fiber, focused-ion-beam (FIB) etching was employed. Here, a simple rotation stage comprising a dc motor and an LR3 battery was built. However, during the development of a prototype rotation stage before finalizing a large-scale remodelling of our FIB etching system, a technical problem was encountered where a spiral line could not be processed without running into breaks and notches in the features. It turned out that the problem was caused by axis blur resulting from an eccentric spinning (or wobbling) of the axis of the fiber caused by its unrestrained free end. The problem was solved by installing a rotation guide and an axis suppression device onto the rotation stage. Using this improved rotation stage. we succeeded in the seamless patterning of 1-µm-wide features on the full-circumference surface of a 250-µm-diameter quartz optical fiber (QOF) by FIB etching. [ABSTRACT FROM AUTHOR]