Synthesis temperature dependence of morphologies and properties of cobalt oxide and silicon nanocrystals

Cobalt and cobalt oxide nanocrystals were synthesized on Si substrates from aqueous cobalt nitrate [Co(NO₃)₂·6H₂O] powder via chemical vapor deposition method. Scanning electron microscope, field emission scanning electron microscope, and transmission electron microscope observations show different morphologies, such as continuous films, nano-bars, nano-dices, and nano-strings, depending on the synthesis temperature. The crystal structure characterization was conducted using X-ray diffraction methods. Furthermore, the properties of the samples were characterized using Raman spectroscopic analysis and vibrating sample magnetometer. The morpholo- gy change was discussed in terms of synthesis environments and chemical interactions between cobalt, oxygen, and silicon.     

Development of a Hybrid Simulator for Power System Analysis for a High Penetration of Distributed Generations

Chubu Electric Power Co., Ltd.’s hybrid power system simulator consists of analog models and hybrid models. The power system facilities are downsized as an analog model, while the synchronous generators and the loads are modeled as an actual current source model through the amplifier and the digital model. In recent years, there is a growing interest in analyzing power system dynamic phenomena caused by a high penetration of distributed generations. Therefore, the multifunctional generator model that can simulate distributed generation has been developed.     

Comparison of two-photon excitation laser scanning microscopy with UV-confocal laser scanning microscopy in three-dimensional calcium imaging using the fluorescence indicator Indo-1

Two-photon excitation laser scanning fluorescence microscopy (2p-LSM) was compared with UV-excitation confocal laser scanning fluorescence microscopy (UV-CLSM) in terms of three-dimensional (3-D) calcium imaging of living cells in culture. Indo-1 was used as a calcium indicator. Since the excitation volume is more limited and excitation wavelengths are longer in 2p-LSM than in UV-CLSM, 2p-LSM exhibited several advantages over UV-CLSM: (1) a lower level of background signal by a factor of 6–17, which enhances the contrast by a factor of 6–21; (2) a lower rate of photobleaching by a factor of 2–4; (3) slightly lower phototoxicity. When 3-D images were repeatedly acquired, the calcium concentration determined by UV-CLSM depended strongly on the number of data acquisitions and the nuclear regions falsely exhibited low calcium concentrations, probably due to an interplay of different levels of photobleaching of Indo-1 and autofluorescence, while the calcium concentration evaluated by 2p-LSM was stable and homogeneous throughout the cytoplasm. The spatial resolution of 2p-LSM was worse by 10% in the focal plane and by 30% along the optical axis due to the longer excitation wavelength. This disadvantage can be overcome by the addition of a confocal pinhole (two-photon excitation confocal laser scanning fluorescence microscopy), which made the resolution similar to that in UV-CLSM. These results indicate that 2p-LSM is preferable for repeated 3-D reconstruction of calcium concentration in living cells. In UV-CLSM, 0.18-mW laser power with a 2.φ pinhole (in normalized optical coordinate) gives better signal-to-noise ratio, contrast and resolution than 0.09-mW laser power with a 4.9-φ pinhole. However, since the damage to cells and the rate of photobleaching is substantially greater under the former condition, it is not suitable for repeated acquisition of 3-D images.     

Large-Area Silicon Sheet Technology Status in United States' Department of Energy Photovoltaics Programs†

Large-area silicon sheet technology is being developed under the U.S. Department of Energy's National Photovoltaics Program to realize high-efficiency, low-cost photovoltaic (PV) cells that are the building blocks of PV modules and arrays.

Both ingot technology and ribbon technology sheet-growth approaches are being pursued. The ingot technology includes Czochralski (Cz) growth and casting processes. Large ingots, both cylindrical and square, have been grown to demonstrate feasibility of producing satisfactory ingots for fabricating PV cells. These developments have been largely adopted by industry and Program-sponsored activities have been reduced. Wafering technology is also being developed, using both rotating-blade and linear-motion saws. Wafering appears to have reached a point where additional fundamental understanding of the sawing mechanism is needed to further wafering technology. Empirical developments have been concluded and only limited fundamental studies, which relate to fracture behavior, continue. Ribbon silicon technologies, such as dendritic-web, edge-defined film-fed growth (EFG) edge-supported pulling growth (ESP), and low-angle silicon sheet (LASS) growth are relatively new in comparison with ingot technologies but have shown steady progress. The ribbon-sheet processes have inherent advantages over the ingot silicon processes. They require minimum silicon material usuage, and they eliminate the wafering step. The cost target for encapsulated cells using both ingot and ribbon processes is $0.70/Wp. Steady progress continues toward this target, and the probability of achieving the cost and technology targets for large-area silicon sheet appears high with at least one of several large-area sheet technologies.     

Long Gap Discharge Guiding Experiments Using Strongly and Weakly Ionized Plasma Channels for Laser Triggered Lightning

A study to generate longer plasma channel was conucted to improve probability of triggered lightning. To generate the long laser plasma channel, a strongly and a weakly ionized plasma channels were used in series, a scheme called hybrid method. The strongly and the weakly ionized plasma channels were used for triggering an electrical leader and guiding the leader. The electrical leader propagated through the weakly ionized plasma. Then main discharge occurred between the electrodes. It is found that the streamer was accelerated with both the increase in the plasma density and the increase in an ambient electric field close to the plane electrode.     

Hydrolysis of Soybean Proteins by a Vortex Flow Filtration Membrane Reactor with Aspergillus oryzae Proteases

Proteases consisting of various endo- and exo-proteases were prepared by homogenizing Aspergillus oryzae mycelia using a French-press. The hydrolysis of 1% soybean proteins was carried out at 35°C and pH 7.0. The back-pressure, flux and rotational speed of the reactor affected the hydrolysis rate and productivity. The reactor system could be operated in a continuous process by replenishing the substrate solution, with the concentration adjusted to maintain 0.43% substrate in the reaction vessel. Permeate flux gave a constant product as shown by molecular weight distribution and amino acid composition.     

Proteinaceous Surfactants Produced from Gelatin by Enzymatic Modification: Application to Preparation of Food Items

Proteinaceous surfactants produced from gelatin by papain-catalyzed incorporation of L-leucine n-alkyl esters were used as ingredients replacing conventional surfactants for food use. The incorporation of leucine Cz-C6 alkyl esters gave surfactants effective in making snow jelly. In ice cream making, a leucine C₁₂ alkyl ester-incorporated product used as the surfactant gave a high degree of overrun even in a few minutes from the start of whipping. This surfactant was applicable also to making mayonnaise, with formation of a tine emulsion having favorable hardness and adhesiveness. In bread making as well, the same surfactant was usable and found preferable to monostearin. The use of this surfactant resulted in satisfactory loaf quality as well as slow staling of bread over a long period of storage.