High Accuracy Phase Measurement in Phase-Shifting Speckle Interferometry

A method for accurately measuring information about the deformation of a rough surface object using a phase-shifting speckle interferometer with a television camera and a computer is considered. In this case, the intensity change of the speckle by phase-shifting varies randomly in space because of the statistical property of the speckle. Then, at points with small intensity change, the accuracy of the phase measurement is affected significantly by the quantization error of an analog to digital converter for data recording. To improve the accuracy, the statistical property of the interference speckle must be clarified. This is done theoretically and experimentally, and the experimental results show that higher measurement accuracy can be attained by selecting large amplitude points.Presented at 1996 International Workshop on Interferometry (IWI ‘96), August 27–29, Saitama, Japan.     

EXPRIMENTAL STUDY ON EFFECTS OF A SINGLE POROUS-TYPE ROUGHNESS ELEMENT IN A PARALLEL-PLATE DUCT

Experiments were carried out to examine the effects of a single porous-type roughness element on the insulated wall opposite the smooth heated plate on the heat transfer. The local heat transfer and drag coefficients depend on the porous diameter and the porosity. The local heat transfer coefficient takes a peak, PI, under the porous element in laminar flow. On the other hand, in turbulent flow, it takes two peaks, PI and P2, under and after the element, respectively. The position of peak P2 varies with the height of the element and the Reynolds number. The drag coefficient of the porous element is lower than that of the solid element. According to thermal performance at constant pumping power, this kind of element should be used in laminar flow. In addition, it is estimated that the porous element should be utilized in the composite effects (the turbulence increase and the thermal radiation shielding effect) of heat transfer in order to apply the element effectively.     

Flattening of micro-structured Si surfaces by hydrogen annealing

We report atomic scale flattening of surfaces of microstructures formed on Si wafers by furnace annealing. To avoid thermal deformation of the fabricated structures, advantage was taken of hydrogen annealing, which enables us to decrease the relaxation rate of Si surfaces due to surface hydrogenation. We examined cross-sectional shape and sidewall morphology of 3 μm deep trenches on Si(0 0 1) substrates after annealing at 1000 °C under various H₂ pressures of 40-760 Torr. We successfully formed Si trenches with flat surfaces composed of terraces and steps while preserving the designed trench profile by increasing H₂ pressure to 760 Torr.     

The surface stress of the (1 1 0) and (1 0 0) surfaces of rutile and the effect of water adsorbents

The surface stress on clean TiO₂ (1 1 0) and (1 0 0) surfaces, and those with four types of adsorbent - (i) molecularly adsorbed water, (ii) dissociatively adsorbed water, (iii) dissociatively adsorbed water at an oxygen vacancy, and (iv) adsorbed hydrogen - was investigated in the framework of density functional theory using a slab model. The calculations were intended to rationalize the effect of the artificially introduced stress that occurs in experimentally photoinduced hydrophilicity. Tensile stress was observed for a clean (1 1 0) surface, and a mixture of tensile and compressive stress for a clean (1 0 0) surface. The adsorbate-induced surface stresses were analyzed in terms of the sixfold coordinated character of the surface titanium atoms, hydrogen bonds between the adsorbents and the bridging oxygen atoms, and the change in electron density in the vicinity of the surface.     

On-target separation of analyte with 3-aminoquinoline/α-cyano-4-hydroxycinnamic acid liquid matrix for matrix-assisted laser desorption/ionization mass spectrometry

3-Aminoquinoline/α-cyano-4-hydroxycinnamic acid (3AQ/CHCA) is a liquid matrix (LM), which was reported by Kumar et al. in 1996 for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. It is a viscous liquid and has some advantages of durability of ion generation by a self-healing surface and quantitative performance. In this study, we found a novel aspect of 3AQ/CHCA as a MALDI matrix, which converges hydrophilic material into the center of the droplet of analyte-3AQ/CHCA mixture on a MALDI sample target well during the process of evaporation of water derived from analyte solvent. This feature made it possible to separate not only the buffer components, but also the peptides and oligosaccharides from one another within 3AQ/CHCA. The MALDI imaging analyses of the analyte-3AQ/CHCA droplet indicated that the oligosaccharides and the peptides were distributed in the center and in the whole area around the center of 3AQ/CHCA, respectively. This 'on-target separation' effect was also applicable to glycoprotein digests such as ribonuclease B. These features of 3AQ/CHCA liquid matrix eliminate the requirement for pretreatment, and reduce sample handling losses thus resulting in the improvement of throughput and sensitivity.     

Clinical value of routine use of thin-section 3D MRI using 3D FSE sequences with a variable flip angle technique for internal derangements of the knee joint at 3T

PurposeTo determine the clinical value of routine use of thin-section 3D MRI using 3D FSE sequences with a variable flip angle technique for internal derangements of the knee joint at 3 T.Method and MaterialsThirty-four knees in 34 patients suspected of having internal derangements of the knee joint were included. Following standard 2D MRI protocol including sagittal PDWI, T1WI and T2*WI, coronal fat-suppressed PDWI, and axial fat-suppressed PDWI with 3-4 mm thicknesses, fat-suppressed and water-excitation PDWI using 3D FSE sequences with a variable flip angle technique with 0.6 mm thickness were obtained in coronal plane and the three major planes with 1 mm thickness (3D MRI) was reformatted. The standard 2D MRI protocol and reformatted 3D MRI protocol (three sagittal 2D sequence images plus 3D MRI) were independently analyzed by two radiologists concerning presence or absence of lesions in the menisci, cartilage, and ligament. Interobserver agreements in both the MRI protocols were assessed by weighted-kappa coefficients. Regarding diagnostic accuracy, areas under the receiver operating characteristic curves (Az values) of both the MRI protocols were compared.ResultsThirty-eight meniscal lesions, 39 cartilage lesions, and 20 ligamentous lesions were surgically detected. Excellent interobserver agreements (kappa = 0.91–0.98) were seen in both the MRI protocols, with a slightly better tendency in the reformatted 3D MRI protocol. Average Az values in detection of the meniscal, cartilage, and ligamentous lesions were significantly higher in the reformatted 3D MRI protocol than in the standard 2D MRI protocol (p < 0.01 or p < 0.001).ConclusionRoutine use of reformatted thin-section 3D MRI using 3D FSE sequences with a variable flip angle technique may improve diagnostic accuracy and confidence in detection of internal derangements of the knee joint.     

Development of ultrawide-angle compact camera using free-form optics

Digital imaging enables us to easily obtain, store, process and display images as digital data, and it is used not only for digital cameras but also for surveillance and in-vehicle cameras, measuring devices, and so on. On the basis of our studies, a free-form optic is not suitable for a high-definition zooming capability; however, it makes optical devices smaller, thinner and lighter. Therefore, it is worth considering the applications of free-form optics other than camera modules for cellular phones. We have investigated the possibilities of miniaturization, which is the most significant feature of free-form optics, and developed a practical application. In this paper, we describe the results of design, prototyping, and evaluation of our ultrawide-angle compact imaging system using free-form optics.     

Three-dimensional numerical thrust performance analysis of hydrogen fuel mixture rotating detonation engine with aerospike nozzle

The propulsive performance for an H₂/O₂ and H₂/Air rotating detonation engine (RDE) with conic aerospike nozzle has been estimated using three-dimensional numerical simulation with detailed chemical reaction model. The present paper provides the evaluation of the specific impulse (I_sp), pressure gain and the thrust coefficient for different micro-nozzle stagnation pressures and for two configurations of conic aerospike nozzle, open and choked aerospike. The simulations show that regardless of the nozzle, increase the micro-nozzles stagnation pressure increases the mass flow rate, the pre-detonation gases pressure and consequently the post-detonation pressure. This gain of pressure in the combustion chamber leads to a higher pressure thrust through the nozzle, improving the I_sp. It was also found that the choked nozzle increases the chamber time-averaged static pressure by 50–60% compared with the open nozzle, inducing higher performance for the same reason explained before.     

Molecular structure and centrifugal distortion constants of isocyanic acid from the microwave,millimeter wave,and far-infrared spectra

The pure rotational spectra of HNCO and DNCO were measured in the far-infrared region from 80 to 350 cm^?1 by a Fourier transform spectrometer with a resolution of 0.1 cm^?1. The ^rR_K branches were measured and assigned for HNCO from K = 1 to 6, and for DNCO from K = 3 to 8. The measured transition wavenumbers were analyzed together with the microwave and millimeter wave data reported by Hocking, Gerry, and Winnewisser [Can. J. Phys.53, 1869–1901 (1975)] and with the far-infrared data of Krakow, Lord, and Neely [J. Mol. Spectrosc.27, 148–176 (1968)] in the low-wavenumber region. The microwave and millimeter wave data of H¹⁵NCO, HN¹³CO, and HNC¹⁸O reported by Hocking et al. were reanalyzed assuming several centrifugal distortion constants to be identical with those of the normal species. The molecular structure of HNCO was reevaluated using a modified substitution method from the rotational constants obtained in this work. The molecule has a bent structure in a trans configuration with $\text{r}\text{(NH) = 0.995}\text{A}\text{?}$, $\text{r}\text{(NC) = 1.314}\text{A}\text{?}$, $\text{r}\text{(CO) = 1.668}\text{A}\text{?}$, ∠HNC = 123.9°, and ∠NCO = 172.6°.     

A method for approximations to the pdf'S and cdf'S of GLSE's and its application to the seemingly unrelated regression model

This paper first develops a valid method for approximations to the pdf's and cdf's of GLSE in linear models and, applying this method to the Zellner estimator with an unrestricted sample covariance in the seemingly unrelated regression model, obtains an approximate pdf with a bound of ordern ⁻² and an approximate covariance matrix with a bound of ordern ⁻³ This research was done at the London School of Economics while the authors were British Council scholars. Kariya is grateful to Professor J. Durbin for a general discussion on asymptotic expansions. Further the authors deeply appreciate Professor Y. Kataoka and anonymous referee for their invaluable comments and suggestions.