Study of the Effect of Fluorine Atom(s) on Fluoromethylated Imines in the Tandem Mannich–Michael-type Reaction

Differences in chemical behavior between non-fluorinated and fluorinated methylimines in the tandem Mannich–Michael-type reaction are described based on NMR and computational studies.     

A METHOD FOR THE PREPARATION OF RAW POWDER FOR THE TANTALUM CAPACITOR: INFLUENCE OF PARTICLE SIZE AND BINDER CONTENT

Raw powder for use in the tantalum solid electrolytic capacitor was prepared by different processes, that is, the wet method (currently used conversion method) and the dry method (the proposed method). The properties of prepared powder from the dry method were compared with those of the wet method. The present report has focused on the relationship between the conditions of binder preparation and the properties of the prepared powder, such as the particle size distribution, angle of repose, and the tap density, respectively. Furthermore, the utility of the dry method was investigated.

Based on the results, it has been clarified that the properties of powder prepared by the dry method differ from those of the wet method. In the case of the dry method, it is suggested that the mechanism of preparation of the fine binder (PMMA powder) differs from that of the coarse binder. Furthermore, based on the experimental results, it has been suggested that the dry method could be used as the preparation method of the raw powder used in the tantalum solid electrolytic capacitor.     

An automatic Euler solver using the unstructured upwind method

A fully-automatic grid generator and an unstructured upwind method for the Euler equations are developed in order to achieve automation in flow computations. The unstructured grid is generated using two techniques: a geometry-adaptive refinement; and a solution-adaptive refinement. The former introduces information about the flowfield geometry into the grid, and the latter introduces the fluid physics. A combination of these two techniques enables the generation of a grid in a fully-automatic manner. Flowfields are solved by an unstructured upwind solver, which is an extension of the flux-vector splitting method of Van Leer for use on arbitrary-shaped unstructured meshes. This robust flow solver with the automatic grid generator can be a useful CFD tool for routine engineering work. The method is applied to external and internal flow problems to demonstrate its capability.     

Snow Entrainment Coefficient Estimated by Field Observations and Wind Tunnel Experiments

The boundary condition for concentration of snow particles at the bed is necessary to calculate snowdrifts by a numerical analysis model. The flux type or the gradient type boundary conditions are reasonable. An idea of an entrainment coefficient of snow particle at the snow surface is useful. The values of the coefficient are considered to be a function of the density and viscosity of the working fluid and the properties of snow particles. In this paper, the values of the coefficient are estimated based on the k–ε turbulence model and the distribution of snow particle flux observed at the Mizuho Station, Antarctica in 2000, assuming the steady, fully developed flow over a flat snow surface. The snow entrainment coefficient is two or three orders smaller than the sand entrainment coefficient in a river. The reason is that the specific weight of snow particles in air is much larger than that of sand particles in water.     

Polymer-electrolyte water electrolysis

The electricity for the electrolyzer is supplied by a variable electricity supply unit that simulates actual outputs of both series and parallel combinations of solar cells exposed to various solar intensities. An amorphous-silicon solar cell is used as a sensor for the unit The operation was continued for more than 600 days without trouble. The case of direct connection of the solar cell and polymer electrolyte (PE) water electrolyzer is simulated: the test results show that more than 95% of the peak electricity power of the solar battery can be utilized for the electrolyzer over various solar radiation conditions.     

Environmental protection: researches in National Institute of Radiological Sciences

Some studies for radiological protection of the environment have been made at the National Institute of Radiological Sciences (NIRS). Transfer of radionuclides and related elements has been investigated for dose estimation of non-human biota. A parameter database and radionuclide transfer models have been also developed for the Japanese environments. Dose (rate)-effect relationships for survival, growth and reproduction have been investigated in conifers, Arabidopsis, fungi, earthworms, springtails, algae, duckweeds, daphnia and medaka. Also genome-wide gene expression analysis has been carried out by high coverage expression profiling (HiCEP). Effects on aquatic microbial communities have been studied in experimental ecosystem models, i.e., microcosms. Some effects were detected at a dose rate of 1 Gy day(-1) and were likely to arise from interspecies interactions. The results obtained at NIRS have been used in development of frameworks for environmental protection by some international bodies, and will contribute to environmental protection in Japan and other Asian countries.     

Theoretical Estimation of Changes in Plane Elastic Waves due to Cylindrical Inclusions

Changes in amplitude and phase shifts in plane elastic waves were theoretically estimated when they propagated through an elastic body containing cylindrical inclusions. Based on the integral equation suggested by Lavrov et al., these changes were calculated in the case when only one cylindrical inclusion was located in the body and the propagating waves have a single frequency. These calculations were expanded to more practical case when multiple cylindrical inclusions aligned in the body and the waves have some frequency band. The changes in amplitude and phase shifts calculated were associated to the changes in apparent sonic velocity and attenuation coefficient due to a structural change in the material. This theoretical approach contributes to a quantitative damage evaluation based upon structural changes in various materials by measuring the acoustical parameters such as apparent sonic velocity and attenuation coefficient.     

Bubble behavior in vertical tube banks installed in a fluidized bed

Fluidized bed combustion is one of the advantageous technologies for coal and/or incineration firing especially with respect to the environmental protection of emissions, such as NO_x/SO_x. Bed material movement in such a fluidized bed has a prime importance in the heat transfer process. Thus, quantitative measurement of the bed material movement and the void fraction are indispensable for better understanding of the fluidized bed. In this investigation, neutron radiography is applied to visualize the bed material movement in a simulated fluidized bed heat exchanger installed with vertical tubes. Bubble behavior and void fraction profile are obtained by the image processing technique. Bubble movement is highly restrained by these vertical tubes, so that the bubbles rise up along the tube. The bubble diameter is well correlated by the modified Mori and Wen's correlation taking into account the pitch of the tube arrangement. The bubble rise velocity and void fraction are well correlated by applying the drift‐flux model. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 727–739, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10127     

Cellular array processor CAP and applications

The general-purpose, highly parallel, cellular array processor (CAP) we developed features multiple-instruction stream, multiple-data stream (MIMD) processing and image display. Processor elements can number in several hundreds. The present system uses 256 processors. Each processor element consists of a general-purpose microprocessor, memory, and a special VLSI chip that performs parallel-processing-specific functions such as processor communication and synchronization. The VLSI has two 2M byte/s independent common bus interfaces for data broadcating and six 15M bit/s serial communication ports for local data communication. The chip also can process image data in real time for multiple processors. Use of the communication interfaces enables a variety of processor networks to be configured. One CAP application has been computer graphics, in which ray tracing is used to generate quality images.     

Dissolution and Absorption of Nipedipine from Nifedipine-Polyvinylpyrrolidone Coprecipitate

Attempt was made to develop the solid dosage form of nifedipina which showed good absorption rate and total bioavailability. Nifedipine is a poorly water-saluble drug, whom bioavailability is low when administered orally in the crystalline form. Solutions of nifedipine were well absorbed from the gastrointestinal tract. The dissolution rate of PVP-nifedipine coprecipitates exhibited rapid dissolution rate. X-ray diffraction data suggested the lack of crystallinity in the coprecipitate. The relation between the dissolution rates and average molecular weights of PVP was studied. Nifedipine in the copretipitate was chemically stable to heat and humidity, but the dissolution rate of nifedipine from the coprecipitate stored at 21° and 75% R.H. markedly decreased. X-ray diffraction data revealed that it might be due to the transformation of amorphous form of nifedipine to crystalline form under higher relative humidity. The gastrointestinal absorption of nifedipine in beagle dogs after oral administration of the coprecipitate was increased than that after oral adniniatration of the physical mixture.