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A study was conducted on ultrafast all-optical switches based on semiconductor quantum well structures for the development of modulators or switches for ultrafast all-optical networks in the future. The application of ultrashort intersubband light pulses to maintain the sufficiently low optical energy required for device operations is considered. A novel scheme based on the simultaneous use of intersubband-control and interband-signal lights both in the pulse form is also proposed.

Experimental analyses of the adhesion between fluorocarbon sublayers and Te-based alloy films during 1 micrometer-sized ablative hole opening reveal that adhesion functions as an energy barrier against molten material flow that occurs during the hole opening. A dynamic force of adhesion dominates the adhesion process and influences the hole opening process. The dynamic force of adhesion values derived from the peel-off strength and the -C-CF- and -CF- structure concentrations that are derived from C1s spectra are similar.

Experimental and optical field analyses of the internal absorption of Zn(Cd)Se/ZnMgSSe semiconductor lasers revealed that the free carrier absorption of 4 per cm of the lasers is less than that of GaAs/AlGaAs semiconductor lasers. The L-I characteristics depend on cavity length of the double heterostructure (DH) lasers that have an absorption coefficient of 4.2 per cm. Differences in absorption coefficient of DH and separate confinement heterostructure (SCH) lasers are due to the GaAs substrate absorption that is 16.53 per cm for SCH and zero for DH lasers.

Experimental testing was used to measure the time variationof population densities of V atoms in absorption levels pertinent to an optically pumped atomic V vapor laser. The results showed that irradiation of aV metal by a pumped laser produces V vapor. Population densities of the ground-state and excited-state V atoms allow the vapor temperature to be estimated, and the temperature in the vapor exhibited an increase from 1800 to 4000 K during laser irradiation.

The magnetic properties of layered oxysulfide Sr2Cu2(Co,Cu)O2S2 with the (Co,Cu)O2 planes are examined. Long time decay is observed at 10 and 75 K and the divergence between zero-field cooled and field cooled magnetizations is observed below 80 K.

Magnetization measurements for the compound SmCo(sub 3)B(sub 2) are performed on loose powder in magnetic fields to 5T and in the temperature region from 4.2 to 60 K. A magnetic first order transition occurs at T=43 K and metamagnetism occurs in the narrow temperature region between 43 and 47 K, for which some possible discussions are given.

A study was conducted to analyze the crystalline electric field at rare earth sites and the induced magnetic moment at a cobalt site in RCo3B2 compounds. The compounds were prepared using an arc furnace. High field magnetization processes were measured at different temperatures. Experimental results indicated that the crystal field parameter is very large and supports a significant magnetic moment induced at the cobalt site.

The electronic transport behaviors of (Ni0.36Nb0.24Zr0.40)100-yHy (0≤y≤20) glassy alloys with distorted nanostructural icosahedral Zr5Nb5Ni3 clusters have been studied as a function of hydrogen content. These alloys show semiconducting, room-temperature superior electric transport, superconducting (onset temperature of 10 K) and electron avalanche behaviors, and electric current-induced voltage (Coulomb) oscillation, as hydrogen content increases. These results suggest that the localization effect of hydrogen at the outside and inside space of the clusters plays important roles in various electron transport phenomena. [ABSTRACT FROM AUTHOR]

By observing light emissions from flares, we systematically investigated transient phenomena from glow to arc discharges under designated durations. To describe properly the discharge flare behavior, we introduced a parameter νa defined as (electrode gap)/(flare traveling time). The main findings are as follows. The parameter νa is proportional to the initial electrode voltage. The maximum value of νa is obtained at a certain gas pressure and it falls on the Paschen curve. The flare behavior follows Townsend’s theory at each instant, therefore, it is governed by the state of the electrolytic dissociation of the gas. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Isothermal capacitance transient spectroscopic studies of Si metal-oxide-semiconductor structures with iron impurities indicate that the interface trap remains unaltered by iron. However, gold impurities affect the trap, implying that various metals have differing influences on the trap. There is an attenuation of trap density and iron concentration during annealing at 400 degrees Celsius.

A unique form of striations, pulse striations, has been observed in a glow discharge by means of a laser-triggered pulse. Unlike conventional striations in a discharge tube, pulse striations are generated near an anode placed in free space. Pulse striations are stereoscopic in shape, appear static, and have a relatively short lifetime of around 1 ms. The wavelength of striations was found to be a function of ambient pressure only, while the relationship between wavelength and pressure in pulse striations was similar to that between specific volume and pressure in the polytropic process of neutral gases. Goldstein's original equation is a function of pressure only and appears to describe more common striation phenomena than Goldstein's law, which is additionally dependent on the radius of the discharge tube. An upper limit of current density, above which striations do not occur, exists. A lower limit of current density was also found in addition to the optimum current density for initiating striations. Laser-triggered pulse striations may enable the easy control of striation duration. [ABSTRACT FROM AUTHOR]

The energy relaxation processes of CdS self-assembled quantum dots (QDs) embedded in ZnSe were investigated. Longitudinal-optical (LO)-phonon resonant structures were discerned in the photoluminescence spectra under the CdS selective excitation, especially under nearly resonant excitation conditions. Strong energy selectivity among the Gaussian distributed energy levels of the QDs are observed in energy relaxation processes, in which excitons are dominantly injected into the QDs whose ground state energies with respect to the excitation energy are equal to the multi-LO-phonon energy of ZnSe. Detection-energy dependent photoluminescence excitation (PLE) measurements also suggest that the coupling strength between the excitons and LO phonons is strongly size-dependent, i.e., coupling is strongly enhanced in smaller QDs. In addition, type-II band alignment of the CdS/ZnSe heterostructure is experimentally confirmed directly by PLE measurements. [ABSTRACT FROM AUTHOR]

A comparison of topographical and electrical properties of hydrogenated and oxidized high-quality B-doped homoepitaxial films was carried out by conductive atomic force microscopy. The topography images of both hydrogenated and oxidized films showed nanoscale flatness and uniformity. The hydrogenated film showed ohmic property indicating the existence of a high-conductivity layer on the surface. A reproducible periodical stripe pattern in the conductivity distribution was also observed indicating the imperfection of H-termination on the step edges. On the other hand, the oxidized surface showed Schottky I-V characteristics and a uniform conductivity distribution without structural dependence, although the surface morphology was modified after the current measurements. [ABSTRACT FROM AUTHOR]

The laser-triggered discharge (LTD) under asymmetric electric fields in air is examined. The introduction of a virtual gas with npd instead of pd in PaschenEs law has shown that the results of LTD in air have coincided with the Paschen curve.

Ionization waves (striation) are used to observe the transition of glow discharge to arc discharge and relevant electron temperatures are determined experimentally. The velocity of ionization waves in a cathode flare has increased from twofold to threefold than in an anode flare and the electron temperature of the anode flare has agreed well with the theoretical value of a positive column in steady glow discharge.

Magnetic properties of Ce(sub 2)[Co(sub 1-x)Ni(sub x)](sub 7)B(sub 3) compounds with x less than equal to 0.3 is studied in the temperature region from 4.2 K to 750 K. It is concluded that the compound Ce2Co7B3 is a quasi-two-dimensional antiferromagnet and becomes Pauli paramagnetic by the Ni substitution.

Studies laser oscillation mechanisms of a krypton-fluorine-laser-pumped iron vapor plasma, the population densities of iron atoms, the temperature and the electron density in iron vapor plasma. Experimental methods; Experimental results; Conclusion.

Investigates the characteristics of an optically pumped tantalum (Ta) vapor laser and the distribution of Ta vapor generated by irradiation of a laser. Experimental methods; Data on the horizontal length of the luminous space of the plasma and of the Ta vapor; Ta laser output energy as a function of the YAG laser energy.

Focuses on a study which demonstrated that the free carrier absorption in zinc cadmium selenide/zinc magnesium sulphur selenide semiconductor lasers is about four centimeters[sup-1] based on two different experiments and an optical field calculation. Cavity length of double heterostructure lasers under current-injected operation; Absorption coefficient; Calculation and discussion.

Investigates the influence of fast neutron irradiation on critical current and its strain dependence in a bronze processed fine multifilamentary Nb[sub3]Sn superconducting composite. List of the specification of the bronze processed fine multifilamentary Nb[sub3]Sn superconducting composite wire specimen; Summary of material parameters of the multifilamentary Nb[sub3]Sn.

Magnetic properties of Ce2(Co1-xNix)7B3 compounds with x⩽0.3 have been studied in the temperature region from 4.2 K to 750 K. It is proposed on the basis of experimental data that the compound Ce2Co7B3 has an antiferromagnetic order where the nearest two ferromagnetic layers separated by 12.9 Å couple very weakly antiferromagnetically. Observed metamagnetic transition in Ce2Co7B3 compound is caused by the spin flip. In the compounds Ce2(Co1-xNix)7B3, Ni atoms substitute preferentially the 2c-site Co atoms, and all atoms in the crystals except for the 2c-site Co atoms [=Co(0) atoms] seem to be nonmagnetic. The compound Ce2(Co1-xNix)7B3 becomes Pauli paramagnetic for x larger than about 0.24. [ABSTRACT FROM AUTHOR]

We have studied the magnetic properties of layered oxysulfide Sr[sub 2]Cu[sub 2](Co,Cu)O[sub 2]S[sub 2] with the (Co,Cu)O[sub 2] planes. Magnetic susceptibility shows a broad maximum indicative of two-dimensional antiferromagnetic nature above 140 K. Below 80 K, the divergence between zero-field cooled and field cooled magnetizations is seen; long time decay is observed at 10 and 75 K, while it is not observed at 45 K. These feature is discussed from the viewpoint of the strongly and frustrated spin system which is different from the traditional spin glass. [ABSTRACT FROM AUTHOR]

Presents a study that measured the effects of pressure on spin-flop transition temperature of manganese (Mn)[sub2-x]-cobalt[subx]-antimony in order to study the nature of spin-flop phase transitions. Discussion on the microscopic origin of the magnetic anisotropy of Mn compounds; Information on the temperature dependence of magnetization for Mn compounds at normal atmospheric pressure.

Reports on the measurement of the pressure effects on magnetic transition temperatures of Mn[sub3]Ga[sub1-x]M[subx]C in order to study the nature of the order-order magnetic phase transitions. Preparation of the polycrystalline samples; Information on the zinc and tin concentration dependences of the magnetic measurements at normal atmospheric pressure.

Presents information on a study which measured the superconducting critical temperature T[subc] on an in situ-formed niobium[sub3]tin superconductor. Fabrication of the superconductor; Characteristics of the superconductor.

Vanadium vapor was produced using a YAG laser applied to a vanadium metal plate. The gasmixing proportions of Xe, HCl and Ne determined the V laser oscillation. Different colors were produced by altering the proportions of these gases, thussuggesting that changes in the gas mixing ratio would alter the XeCl laser wavelength.

Presents information on a study that provided a theoretical interpretation of the damage formation in coated optical glasses. Experimental procedure; Results and discussion.