This paper deals with a mathematical formulation of the scattering from a periodic surface with finite extent. In a previous paper the scattered wave was shown to be represented by an extended Floquet form by use of the periodic nature of the surface. This paper gives a new interpretation of the extended Floquet form, which is understood as a sum of diffraction beams with diffraction orders. Then, the power flow of each diffraction beam and the relative power of diffraction are introduced. Next, on the basis of a physical assumption such that the wave scattering takes place only from the corrugated part of the surface, the amplitude functions are represented by the sampling theorem with unknown sample sequence. From the Dirichlet boundary condition, an equation for the sample sequence is derived and solved numerically to calculate the scattering cross section and optical theorem. Discussions are given on a hypothesis such that the relative power of diffracted beam becomes almost independent of the width of surface corrugation.

The optical recording on an azopolymer surface by the optical fiber probe with a 100 nm diameter aperture was demonstrated. The 150 nm diameter pit was formed by the optical fiber probe coupled with a 50 ns pulse of 10 mW and 488 nm wavelength coherent light.

Self-ordered mesoporous silicate films from organic-inorganic compound materials are successfully fabricated into the surface photo voltage (SPV) type gas sensor device as a gas adsorption insulator layer. These kinds of gas sensors device exhibit NO gas sensing property dependent on their mesoporous film structure. We are succeeded in indication about a possibility of mesoporous silicate film for the SPV type gas sensor application.

The surface potential built across vacuum deposited phthalocyanine (Pc) films on aluminum electrode was investigated by means of electro-modulation spectroscopy. The sandwich-type cells with thin air gap, which becomes a good insulator were used in order to avoid the influence of charge injection. The existence of the surface potential at the metal/organic-material interface induced 1f referenced electro-reflectance (ER) signals. As a result, the surface potential built across vacuum deposited Pc films on aluminum electrode was estimated to be 1.25 V.

We demonstrate a single high-order transverse mode surface emitting laser (VCSEL) with narrow trenches formed on a top surface. The design and the fabrication of a single high-order mode 850 nm GaAs VCSEL with micromachined surface relief are presented. Stable single-mode operation with a side-mode suppression ratio of over 40 dB was obtained in an entire measured current range. We obtained the maximum single mode power of over 3.5 mW and a record low series resistance of below 50 Ω. In addition, a single-lobe far field pattern is demonstrated even under high-order transverse mode operation by loading phase-shift on the top surface. A coupling efficiency with optical fibers is dramatically improved.

The urgent tasks of MOSFET modeling for circuit simulation are easy adaptation to new physical phenomena arising for advancing technologies, and, of course, sufficient simulation accuracy. Approaches currently being pursued for developing such MOSFET models are summarized. Their capabilities for accomplishing these tasks as well as the important remaining problems are discussed. Main focus is given on the model HiSIM, the first commonly available model based on the drift-diffusion approximation developed for 0.10 µm MOSFET technology node.

Verb phrases are sometimes omitted in natural language (ellipsis). It is necessary to resolve the verb phrase ellipses in language understanding, machine translation, and dialogue processing. This paper describes a practical way to resolve verb phrase ellipses by using surface expressions and examples. To make heuristic rules for ellipsis resolution we classified verb phrase ellipses by checking whether the referent of a verb phrase ellipsis appears in the surrounding sentences or not. We experimented with the resolution of verb phrase elipses on a novel and obtained a recall rate of 73% and a precision rate of 66% on test sentences. In the case when the referent of a verb phrase ellipsis appeared in the surrounding sentences, the accuracy rate was high. But, in the case when the referent of a verb phrase ellipsis did not appear in the surrounding sentences, the accuracy rate was not so high. Since the analysis of this phenomena is very difficult, it is valuable to propose a way of solving the problem to a certain extent. When the size of corpus becomes larger and the machine performance becomes greater, the method of using corpus will become effective.

An advanced center biased search algorithm for block motion estimation is proposed in this letter. It adopts an innovative center biased search strategy to get correct motion vector. The computational complexity is reduced by strict application of the unimodal error surface assumption and half stop technique. Experimental results show that proposed algorithm has improved performance as compared to the conventional block matching algorithms.

The measurement sensitivity of microwave surface resistance, Rs, of high temperature superconducting (HTS) thin films using half-wavelength microstrip resonator with copper and HTS ground plane is analyzed for fundamental and higher order modes of the resonator. The estimated sensitivity of Rs-measurement is at least an order of magnitude greater at fundamental resonant frequency compared to when measured using higher order harmonic modes.

A coaxial cable measurement system applicable up to 60 GHz in the cryogenic temperature is developed by using V-connectors. In this system, the fine location of coupling loop antennas can be adjusted by three-dimensional mechanical stages in the low temperature region. In order to verify usefulness of this system, the temperature dependence of surface resistance (Rs) of Y-Ba-Cu-O (YBCO) films was measured at 30 GHz by the two-dielectric resonator method using TE011- and TE013- mode sapphire rod resonators. The measured result of Rs was 0.5 mΩ at 30 GHz and 20 K, which was 1/40, compared with those of copper plates.

The FDTD method needs Fourier analysis to obtain the fields of a single frequency. Furthermore, the frequency spectra of the fields used in the FDTD method ordinarily have wide bands, and all the fields in FDTD are treated as real numbers. Therefore, if the permittivity ε and the permeability µ of the medium depend on frequency, or if the surface impedance used for the surface impedance boundary condition (SIBC) depends on the frequency, the FDTD method becomes very complicated because of convolution integral. In the electromagnetic theory, we usually assume that the fields oscillate sinusoidally, and that the fields and ε and µ are complex numbers. The benefit of introduction of the complex numbers is very extensive. As we do in the usual electromagnetic theory, the authors assume that the fields in FDTD oscillate sinusoidally. In the proposed FDTD, the fields, ε, µ and the surface impedances for SIBC are all treated as the complex numbers. The proposed FDTD method can remove the above-mentioned weak points of the conventional FDTD method.

We have proposed an intracell uplink of a spread-spectrum code-division multiple-access (SS-CDMA) flexible wireless network based on approximately synchronized (AS) CDMA. Since the AS-CDMA has no co-channel interference, complicated transmission power control (TPC) is not required. A modem of the AS-CDMA has been designed and implemented for the Japanese 2.4 GHz industrial, scientific and medical (ISM) band. Using the implemented modem, the degradation of Eb/N0 from the theoretical limit is 1.0 dB at a bit error rate (BER) of 10-3. Under 2-user environment, the degradation of carrier-to-noise ratio (CNR) is 0.5 dB at a BER of 10-3 when the desired-to-undesired signal ratio (DUR) is -20.3 dB. We have evaluated BER performances in cases of varying carrier frequency offset and median DUR with computer simulation. Under 8-user environment, at the carrier frequency offset of 0.3 ppm, the BER with the DUR of -16 dB is found to be 10-3. Using the AS-CDMA with a 4-step open-loop TPC technique, the design of intracell uplink is available.

The vertical-cavity surface-emitting laser (VCSEL) is becoming a key device in high-speed optical local-area networks (LANs) and even wide-area networks (WANs). This device is also enabling ultra parallel data transfer in equipment and computer systems. In this paper, we will review its physics and the progress of technology covering the spectral band from infrared to ultraviolet by featuring materials, fabrication technology, and performances such as threshold, output power, polarization, modulation and reliability. Lastly, we will touch on its future prospects.

A 2D photonic crystal surface-emitting laser using a triangular lattice is developed, and current-injected lasing oscillation is demonstrated. From consideration of the Bragg diffraction condition in the 2D triangular-lattice structure, it is shown that the 2D coupling phenomenon occurs in the structure. As a result of the 2D periodicity of the structure, the longitudinal mode and lateral mode can be controlled, and stable single-mode oscillation is possible over a large 2D area. The lasing mode of the structure is analyzed by calculating the photonic band diagram by the 2D plane-wave expansion method, and we show that four band edges at which the lasing oscillation can occur exist at the Γ point. Current-injected lasing oscillation is successfully demonstrated at room temperature under pulsed conditions. The threshold current density is 3.2 kA/cm2 and the lasing wavelength is 1.285 µm. From the near-field and far-field patterns, it is shown that large-area 2D (diameter 480 µm) lasing oscillation occurs in the device and the divergence angle is very narrow (less than 1.8). We also demonstrate the correspondence between the measured lasing wavelengths and calculated band diagram by comparing the polarization characteristics with the calculated distribution of the electromagnetic field. The results indicate that 2D coherent lasing oscillation occurs due to the multi-directional coupling effect in the 2D photonic crystal. Finally, we show that the polarization patterns of the lasers can be controlled by introducing artificial lattice defects from the theoretical calculation.

Bidirectional reflection distribution functions (BRDFs) of commercially pure titanium sheets with three different kinds of surface morphology were measured. Those experimental BRDFs were analyzed by using Phong's reflection model. Topographic measurements of the specimens' surfaces were performed with using a stylus-method. An explicit microfacet model based on topographic data was proposed. With using the explicit microfacet model and geometrical optics the calculated BRDFs were obtained and then compared with the experimental BRDFs. Both of them were in a good agreement. Through this comparison physical meanings of Phong's reflection model were discussed. We concluded that with using the explicit microfacet model it will be possible to calculate the BRDF of the materials' surface in arbitrary illumination conditions and that this modeling will be useful to develop new aesthetic surface appearance in material industries, computer graphics, architectural design and surface science.

We have developed a novel self-alignment process using the surface tension of the liquid resin for assembly of electronic or optoelectronic devices. Though the liquid resins have a characteristics as low as one tenth of the surface tension of solder in general, restoring forces for self-alignment capability can be produced by making it constrained on the 3-dimensional pads on chip and substrate. In this paper, its principle and characteristics are described and the relationship between process parameters and joint geometry were examined. And the possibility of self-alignment process was verified by analytic numerical method and scaled-up experiment. A self-alignment accuracy was examined experimentally and show that it became less than 0.4 µm. It can provide a useful information on various parameters involved in joint geometry and optimal design guideline to generate the proper profiles.

We present an algorithm for computing the Minkowski sum of two surfaces of revolution with parallel axes, each defined as a rotational sweep of a slope-monotone closed curve. This result is an extension of that due to Sugihara et al., where the Minkowski sum for two slope-monotone closed curves in the plane is defined.

This paper proposes a precise method of realizing simultaneous measurement of microscopic defects and the macroscopic three-dimensional shapes of planar objects having specular reflection surfaces. The direction vector field of surface tilt is evaluated directly by the introduction of a moving slit-light technique based on computer graphic animation. A reflected image created by the moving slit-light is captured by a video camera, and the image sequence of the slit-light deformation is analyzed. The obtained direction vector field of the surface tilt recovers the surface shape by means of integration. Two sample objects, a concave mirror and a plane plastic injection molding, are tested to measure the performance of the proposed method. Surface anomalies such as surface dent and warpage are detected quantitatively at a high resolution (about 0.2 [µm]) and a high accuracy (about 95%) in a wide area (about 15 [cm]) of the test object.

Surface passivation process of GaN utilizing electron-cyclotron-resonance (ECR) excited plasma has been characterized and optimized for realization of stable operation in GaN-based high-power/high-frequancy electronic devices. From XPS analysis, the NH4OH treatment as well as the ECR-N2 and ECR-H2 plasma treatments were found to be effective in removing natural oxide and contaminants from the GaN surface. The SiNx/GaN structure prepared by the ECR excited plasma chemical vapor deposition (ECR-CVD) process showed better C-V behavior compared to the SiO2/GaN structure. Surface treatment process using the ECR plasma improved interface properties and achieved the Dit value of 21011 cm-2 eV-1 or less. An estimate of the valence band offset by XPS showed that the present SiNx/n-GaN structure has a type-I band lineup, suitable for the surface passivation of GaN-based devices. No pronounced stress remained at the SiNx/GaN interface, which was confirmed by Raman spectroscopy.

A periodic approach introduced previously is applied to the TM wave scattering from a finite periodic surface. A mathematical relation is proposed to estimate the scattering amplitude from the diffraction amplitude for the periodic surface, where the periodic surface is defined as a superposition of surface profiles generated by displacing the finite periodic surface by every integer multiple of the period . From numerical examples, it is concluded that the scattering cross section for the finite periodic surface can be well estimated from the diffraction amplitude for a sufficiently large .