Ion sources, systems and methods are disclosed. In some embodiments, the ion sources, systems and methods can exhibit relatively little undesired vibration and/or can sufficiently dampen undesired vibration. This can enhance performance (e.g., increase reliability, stability and the like). In certain embodiments, the ion sources, systems and methods can enhance the ability to make tips having desired physical attributes (e.g., the number of atoms on the apex of the tip). This can enhance performance (e.g., increase reliability, stability and the like).

Ion sources, systems and methods

A speech synthesis system can select recorded speech fragments, or acoustic units, from a very large database of acoustic units to produce artificial speech. The selected acoustic units are chosen to minimize a combination of target and concatenation costs for a given sentence. However, as concatenation costs, which are measures of the mismatch between sequential pairs of acoustic units, are expensive to compute, processing can be greatly reduced by pre-computing and caching the concatenation costs. Unfortunately, the number of possible sequential pairs of acoustic units makes such caching prohibitive. However, statistical experiments reveal that while about 85% of the acoustic units are typically used in common speech, less than 1% of the possible sequential pairs of acoustic units occur in practice. A method for constructing an efficient concatenation cost database is provided by synthesizing a large body of speech, identifying the acoustic unit sequential pairs generated and their respective concatenation costs, and storing those concatenation costs likely to occur. By constructing a concatenation cost database in this fashion, the processing power required at run-time is greatly reduced with negligible effect on speech quality.

Methods and Apparatus for Rapid Acoustic Unit Selection From a Large Speech Corpus

After an amorphous semiconductor thin film is crystallized by utilizing a catalyst element, the catalyst element is removed by performing a heat treatment in an atmosphere containing a halogen element. A resulting crystalline semiconductor thin film exhibits {110} orientation. Since individual crystal grains have approximately equal orientation, the crystalline semiconductor thin film has substantially no grain boundaries and has such crystallinity as to be considered a single crystal or considered so substantially.

Semiconductor thin film and semiconductor device

This invention relates to temperature compensated FFPs with improved means for alignment of optical fibers. The invention provides ferrule holders with shaped ferrule passageways, as components of FFP alignment fixtures, in which optical fiber ends can be readily aligned using the ferrule rotary alignment method. The ferrule holders have a composite structure facilitating temperature compensation required for applications to PZT-tuned FFPs. The ferrule holder has a core and peripheral region made of materials having different thermal expansion coefficients. The holder core in contact with the ferrule is made of a material having a thermal expansion coefficient substantially matched to that of the ferrule material. In addition, ferrule holders are provided with a means for changing the points of contact between a secured ferrule and its holder which allows wavelength drift as a function of temperature in FFPs to be adjusted.

Temperature compensated fiber fabry-perot filters

Quantum structures made from epitaxial semiconductor layers have revolutionized our understanding of low-dimensional systems and are used for ultrafast transistors, semiconductor lasers, and detectors. Strain induced by different lattice parameters and thermal properties offers additional degrees of freedom for tailoring materials, but often at the expense of dislocation generation, wafer bowing, and cracks. We eliminated these drawbacks by fast, low-temperature epitaxial growth of Ge and SiGe crystals onto micrometer-scale tall pillars etched into Si(001) substrates. Faceted crystals were shown to be strain- and defect-free by x-ray diffraction, electron microscopy, and defect etching. They formed space-filling arrays up to tens of micrometers in height by a mechanism of self-limited lateral growth. The mechanism is explained by reduced surface diffusion and flux shielding by nearest-neighbor crystals.

http://science.sciencemag.org/content/sci/335/6074/1330.full.pdf

Scaling Hetero-Epitaxy from Layers to Three-Dimensional Crystals

A model for molecular‐beam‐epitaxy growth is proposed to describe the morphology formed on a nonplanar, profiled surface that may consist of multifaceted crystal structures. Anisotropy of growth rate is introduced as a main factor for explaining the observed growth morphology. We show that on the nonplanar surface, the migration of adatoms modifies the growth rate at each point of the growing surface and thus affects the formation of the morphology within the range of migration length. The model can successfully describe the growth behavior including the development of sharp facet edges, since it is formulated in terms of a difference (rather than differential) equation which does not require the continuity of surface slope. The morphology simulated on the basis of this model agrees to experimental results of GaAs growth.

Model for molecular‐beam‐epitaxy growth over nonplanar surfaces

A semiconductor device has a substrate composed of a semiconductor which has one of sphalerite and diamond crystal structures. The substrate has a plane orientation inclined at 0.5° to 15° with respect to one of {111} and {110} planes indicated by Miller indices. A first semiconductor layer is formed on the substrate. The first semiconductor layer has a sawtooth-shaped first periodic structure consisting of one of the {111} and {110} planes indicated by the Miller indices and at least one plane indicated by another index. A second semiconductor layer is formed on the first semiconductor layer. The second semiconductor layer has a second periodic structure having a phase shifted from a phase of the first periodic structure.

Semiconductor device having diffraction grating

A semiconductor laser having a laser resonator structure having a substrate with a trapezoidal projection forming on both sides of an upper base an inclined surface extending along a resonating direction of a resonator, a first semiconductor layer of a first or second conductivity type formed on the substrate, an active layer for generating a laser beam, a second semiconductor layer formed on the substrate and to which an impurity of a convertible conductivity type is doped with a portion of the second semiconductor layer above the inclined surface of the substrate having the first conductivity type and the other portion having the second conductivity type, and a pair of electrodes causing a current to flow through the active layer.

Semiconductor laser having a lateral p-n junction utilizing inclined surface and method of manufacturing same

A model allowing a consistent description of growth evolution on nonplanar surface by molecular‐beam epitaxy and metalorganic vapor‐phase epitaxy is presented. It is shown that the elemental kinetic processes (surface migration, incorporation, and desorption) are reduced to an equation of continuity for an atomic flow on a growing surface. In metalorganic vapor‐phase epitaxy this continuity equation is coupled with the diffusion equation in vapor phase, permitting to calculate self‐consistently the density distribution of reactant species in vapor and of the adatoms in the surface layer. In the model, anisotropic properties of growth are introduced by taking into account the surface diffusion around the atomic steps. The formulation of the model is based on the discrete form of the continuity equation (rather than the differential form) and therefore allows description of the growth behavior including the development of sharp facet edges. The method of simulation for nonplanar growth is illustrated in det...

Modeling of molecular‐beam epitaxy and metalorganic vapor‐phase epitaxy on nonplanar surfaces

A speech synthesizing apparatus acquires a synthesis unit speech segment divided as a speech synthesis unit, and acquires partial speech segments by dividing the synthesis unit speech segment with a phoneme boundary. The power value required for each partial speech segment is estimated on the basis of a target power value in reproduction. An amplitude magnification is acquired from the ratio of the estimated power value to the reference power value for each of the partial speech segments. Synthesized speech is generated by changing the amplitude of each partial speech segment of the synthesis unit speech segment on the basis of the acquired amplitude magnification.

Mitsuru Ohtsuka

Papers

Model for molecular‐beam‐epitaxy growth over nonplanar surfaces

Semiconductor device having diffraction grating

Semiconductor laser having a lateral p-n junction utilizing inclined surface and method of manufacturing same

Modeling of molecular‐beam epitaxy and metalorganic vapor‐phase epitaxy on nonplanar surfaces

Speech synthesizing method and apparatus