Simplification of Space-Variant Parallel Logic Operations Using the Temporal Method

A time-domain encoding method (temporal method) for space-variant parallel logic operations, which can execute different operations in parallel, is proposed. The temporal method is based on temporal encoding of two input patterns, temporal gating of the coded pattern, and decoding by temporal addition of the gated patterns. The first feature of the proposed method is that parallel logic operations can be performed without complex pattern transformations. The second feature is that the logical output can be directly fed to succeeding systems without specific decoding. Therefore, the logic operation system can be constructed using conventional optics and existing spatial light modulators. In order to confirm these features, an optoelectronic experimental system is constructed and space-variant parallel logic operations are performed.     

High Sensitive Detection of Trace Gases Using Optical Heterodyne Method with a High Finesse Intra-Cavity Resonator

A novel highly sensitive method to detect the concentration of trace gas for environmental purposes is proposed. This method includes the application of frequency modulation for stabilization of laser frequency, together with optical heterodyne measurement. The shift of resonance frequency of the Fabry-Perot cavity resonator is due to the change of refractive index, accompanied by the dispersion effect due to the presence of a target gas (e.g., methane, carbon dioxide or nitrogen dioxide) inside the Fabry-Perot cavity.     

Feasibility study of low-power multiquantum-well vertical transmission optical amplifiers for optical interconnection

Performance of 0.98-μm InGaAs strained multiquantum-well Fabry-Perot vertical transmission optical amplifiers (MQW FP VTOAs) for optical inter-board connection is analyzed theoretically, and compared with those of GaAs MQW, GaAs bulk, and InGaAsP bulk VTOAs. A low-power operation of about 2 mA and a cascadability of several hundred boards are predicted for an InGaAs strained MQW FP VTOA.     

Adsorption behavior of various metals on a weakly basic anion-exchange resin in sulfuric acid media

A systematic study is presented on the adsorption behavior of some 20 metals on a weakly basic condensed phenol resin, Amberlite CG-4B, in sulfuric acid media. The distribution coefficients were determined over a sulfuric acid concentration range of 0.005 M to 2 M. The metals adsorbed are similar to those which exhibit strong adsorption on a strongly basic resin, but the magnitudes of the distribution coefficients and the adsorption sequences differ considerably between the two types of the resin. Several two- and three-component separations of analytical interest are possible. A new method for the separation of titanium(IV) is described; this is based on its high adsorption on CG-4B from sulfuric acid media containing hydrogen peroxide.     

Palladium metal-catalyzed cross-coupling of aryl iodides with arylmagnesium bromides. Synthesis of fluorobiphenyls

Palladium metal functions as catalyst in the coupling of iodobenzene with phenylmagnesium bromide. For practical purposes, palladium(II) chloride was used instead, since it is converted to palladium metal during the course of the reaction. A high catalytic effect of palladium(II) chloride at low concentrations (saturated solutions in tetrahydrofuran, < 0.0001 molar equiv.) was exhibited in cross-couplings yielding several fluorobiphenyls.     

Some modifications of improved estimators of a normal variance

Consider the problem of estimating a normal variance based on a random sample when the mean is unknown. Scale equivariant estimators which improve upon the best scale and translation equivariant one have been proposed by several authors for various loss functions including quadratic loss. However, at least for quadratic loss function, improvement is not much. Herein, some methods are proposed to construct improving estimators which are not scale equivariant and are expected to be considerably better when the true variance value is close to the specified one. The idea behind the methods is to modify improving equivariant shrinkage estimators, so that the resulting ones shrink little when the usual estimate is less than the specified value and shrink much more otherwise. Sufficient conditions are given for the estimators to dominate the best scale and translation equivariant rule under the quadratic loss and the entropy loss. Further, some results of a Monte Carlo experiment are reported which show the significant improvements by the proposed estimators.     

Radiation clusters and the active control of sound transmission into a symmetric enclosure

Radiation cluster control is proposed for the purpose of attenuating harmonic sound transmission into a symmetric enclosure using error signals derived from structural vibration sensors. The approach falls into a category of middle authority control, which is between LAC (low authority control: structural modal control) and HAC (high authority control: radiation modal control), possessing the benefit of practicality over LAC, while providing high control performance and some flexibility of control gain assignment similar to HAC. The structure of a radiation cluster control system is outlined, showing that it is possible to control a target cluster without affecting the other clusters. A design procedure for the radiation cluster control system is then proposed. Numerical results are also presented.