Structural analysis of multi-walled carbon nanocoils synthesized with Fe-Sn catalyst supported on zeolite

Thin carbon nanocoil (CNC) with a fiber diameter of less than 50 nm was synthesized by catalytic chemical vapor deposition using Fe-Sn catalyst supported on zeolite. The chemical vapor deposition parameters of reaction temperature, gas flow rate of N2 as dilute gas and C2H2 as source gas were 650-750 degrees C, 1000 ml/min and 50-300 ml/min respectively. Transmission electron microscopic observation revealed that thin CNCs had a hollow and multi-walled structure with cylindrical graphitic layers. More than 90% of the CNCs obtained were multi-walled CNCs (MWCNCs), and the remainder was columnar CNCs without a hollow structure. Three-dimensional images of an MWCNC with Au nanoparticles on its surface were reconstructed by electron tomography and confirmed that the MWCNC had a three-dimensional helical shape.     

Stator‐core structure and winding technology for EPS motors

Electric power steering (EPS) motors must have the performance characteristics of precision machines. They should be compact and produce high power. Moreover, the loss torque and the change of loss torque should be as low as possible. In this study, dividing the stator core into small blocks and winding the coils densely on the blocks are shown to be effective techniques for achieving compact high‐power motors. We examined whether I‐shaped divided cores or T‐shaped divided cores were more suitable for EPS motors in terms of motor performance and production cost. We built two experimental motors, one with I‐shaped divided cores and the other with T‐shaped divided cores, and measured three important characteristics of EPS motors: output torque, loss torque, and loss torque change. The T‐type motor proved to have better performance for all three characteristics. Moreover, the productivity of the T‐type motor was shown to be higher than that of the I‐type motor, indicating that overall, T‐shaped divided cores are advantageous for the stators of EPS motors. Next, we considered a new winding method for the continuous winding of two T‐shaped cores in order to achieve a compact terminal connection board. The extending lines made by the new winding method do not extend beyond the coil end. Therefore, this method will contribute to reduction of the axial dimension of EPS motors. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(1): 35–42, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21085     

Configuration of Shock Waves in Two-Dimensional Overexpanded Jets

An experimental and analytical study has been carried out to obtain the clear understanding of a shock wave transition associated with a steady two-dimensional overexpanded flow. Two-dimensional inviscid theory with respect to a shock wave reflection is used in the present study on the characteristic of shock waves. The results obtained from the flow analysis are compared with those obtained from flow visualizations. It is shown that in the region of regular reflection, the angle of an incident shock wave becomes lower than that calculated by two shock theory with an increment in the ratio pe/pb of the nozzle exit pressure pe to the back pressure pb. It is indicated that the configuration of shock waves in overexpanded jets is influenced by the divergent angle at the nozzle exit. Also it is shown from the flow visualization that a series of shock waves move into the nozzle inside with a decrease in pressure ratio pe/pb, even if the pe/pb is under overexpanded conditions.     

Large area thin film Si module

An initial efficiency of 14.1% (J_sc=13.6 mA/cm², V_oc=1.392 V, FF=74.3%) has been achieved for a-Si/transparent interlayer/poly Si solar cell (total area of 1 cm²). Both a-Si and crystalline Si films were fabricated by plasma chemical deposition at low temperature. The short circuit current was enhanced by the introduction of a transparent intermediate layer. An initial aperture efficiency of 11.7% has been achieved for 910×455 mm² a-Si/poly Si integrated solar cell submodule, where the laser-scribing techniques were applied for series interconnections. The results of our first run of 266 submodules in our pilot plant showed the average efficiency of 11.2%, which is applicable for mass production.     

Self‐structured serrated edges of chemically oxidized poly(dimethylsiloxane) disks

Serrated structures on a micrometer scale were spontaneously formed along the edge of a poly(dimethylsiloxane) (PDMS) disk using the following procedure. First, a drop of PDMS prepolymer was placed on a glass slide, followed by vulcanization. Second, the obtained PDMS disk was soaked in a mixture of sulfuric acid and nitric acid to form a serrated structure. Consideration of the mechanism of the structure formation was based on the following results. (1) The acid oxidized the PDMS surface, which was then swollen with the acid mixture or water to form wrinkles. (2) The wrinkle wavelength depended on the thickness of the PDMS film. (3) The thickness of the PDMS disk varied near its edge because the meniscus of the drop of the PDMS prepolymer was retained after the vulcanization. These results suggest that the thickness gradient of the PDMS disk led to the spontaneous formation of a serrated edge structure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40767.     

The Calcium Phosphate Matrix of FGF-2-Apatite Composite Layers Contributes to Their Biological Effects

The purpose of the present study was to fabricate fibroblast growth factor (FGF)-2-apatite composite layers on titanium (Ti) pins in one step at 25 °C using a supersaturated calcium phosphate (CaP) solution, and to evaluate the physicochemical characteristics and biological effects of the coated Ti pins compared with coated Ti pins fabricated at 37 °C. Ti pins were immersed in a supersaturated CaP solution containing 0.5, 1.0, or 2.0 µg/mL FGF-2 at 25 °C for 24 h (25F0.5, 25F1.0, and 25F2.0) or containing 4.0 µg/mL FGF-2 at 37 °C for 48 h (37F4.0). Except for the 25F0.5, the chemical compositions and the mitogenic activity levels of FGF-2 of the composite layers formed by these two methods were similar, except for the Ca/P molar ratio, which was markedly smaller at 25 °C (1.55–1.56 ± 0.01–0.02, p = 0.0008–0.0045) than at 37 °C (1.67 ± 0.11). Thus, either the apatite was less mature or the amount of amorphous calcium phosphate was higher in the composite layer formed at 25 °C. In vivo, the pin tract infection rate by visual inspection for 37F4.0 (45%) was lower than that for 25F1.0 (80%, p = 0.0213), and the rate of osteomyelitis for 37F4.0 (35%) was lower than that for 25F0.5 (75%, p = 0.0341). The extraction torque for 37F4.0 (0.276 ± 0.117 Nm) was higher than that for 25F0.5 (0.192 ± 0.117 Nm, p = 0.0142) and that for 25F1.0 (0.176 ± 0.133 Nm, p = 0.0079). The invasion rate of S. aureus for 37F4.0 (35%) was lower than that for 25F0.5 (75%, p = 0.0110). On the whole, the FGF-2-apatite composite layer formed at 25 °C tended to be less effective at improving fixation strength in the bone-pin interface and resisting pin tract infections. These results suggest that the chemistry of the calcium phosphate matrix that embeds FGF-2, in addition to FGF-2 content and activity, has a significant impact on composite infection resistance and fixation strength.     

Beta-Glucosylceramide Administration (i.p.) Activates Natural Killer T cells In Vivo and Prevents Tumor Metastasis in Mice

Natural killer (NK) T cells are well known to play important roles in both tumor rejection and the defense against infectious. Therefore, the antitumor potential of NKT cell-activating antigens have been the focus for the development of NKT cell-based immunotherapies. Up to now, several studies have revealed that the administrations of glycolipids (e.g. α-galactosylceramide) can successfully treat certain metastatic tumors. However, liver injuries appeared upon the application of these antigens. We previously examined the potential of using β-glucosylceramide (β-GlcCer) to inhibit tumor metastasis to the liver. The aim of this study was to determine the antimetastatic effects of β-GlcCer and its impact on the activation of NKT cells. Intraperitoneal administration of β-GlcCer enhanced the production of interferon-γ from hepatic lymphocytes containing NKT cells, and increased the cytotoxicity of hepatic lymphocytes against tumor cells. Moreover, β-GlcCer administration suppressed the hepatic metastasis of tumors in wild type (WT) mice, but not in CD1d (-/-) or Jα18 (-/-) mice. The drawback associated with the other glycolipids in liver injury was not noted in WT mice treated with the continuous daily administration of β-GlcCer for 2 weeks. The present study demonstrated that β-GlcCer treatment activates invariant NKT cells, thus resulting in the inhibition of tumor metastasis.     

Synthesis of chiral hybrid nanotubes of magnetite nanoparticles and conducting polymers

New chiral magnetite nanoparticles with a polymerizable group produced polymer composite films on an electrode surface and the hybrid nanotubes of magnetite nanoparticles and polythiophene from their template-based electropolymerization.     

Asian international grid connection and potentiality of DC superconducting power transmission

In 2011, a large scale earthquake and tsunami hit the northeastern coast of Japan, and nuclear plants were damaged to a large extent. Before the Tsunami, 54 nuclear plants were operated, however presently, only three nuclear plants are in operation. Therefore, Japan is suffering from high price of electricity and low supply reliability. In generation mix, nuclear plants generate only one percent and 87 percent of electricity is generated by fossil energy. This is not preferable for Japan from the viewpoints of energy security and stable electricity supply. Therefore, it is mandatory to increase sustainable energy and to decrease consumption of fossil fuel. International grid connection and the Global Energy Interconnection will be one of countermeasures against these problems existing in Japan. In this paper, international grid connection initiatives proposed in Asia are described and features and issues of electric power grids in Japan are discussed to implement the international grid connection. As the key technology for implementing the international grid connection, the present status of DC superconducting power transmission lines and power converters for long-distance power transmission lines are presented. In conclusion, conditions and legal frameworks for realizing the international grid connection are described.     

Interpolation Errors in Rectangular and Diamond Characteristic Grids

Analytical predictions of numerical errors in method of characteristics analyses using time-line interpolation in a rectangular grid are obtained for (1) both time-line and space-line interpolation and (2) both rectangular and diamond grids. Amplitude and frequency errors are investigated for each of these four cases using purpose-developed polynomial transfer matrices. Both semiinfinite and finite pipes are investigated. The time-line analysis permits reach back in time and the space-line analysis permits reach out in space. A common definition is adopted for the Courant number in the four cases and it is shown why stability can be achieved in reach-out analyses with Courant numbers greater than 1. In contrast with most work on error estimation, the predicted errors are obtained analytically, not numerically. This is made possible by restricting the analysis to special, but important, cases such as liquid-filled pipes in which the waves may be assumed to propagate at constant speed. Furthermore, the development is restricted to inviscid flows, thereby enabling interpolation errors to be assessed in the absence of complicating influences of discretization errors. In contrast with the latter, it is found that interpolation errors are more sensitive to the shape of numerical grids (i.e., Courant number and rectangular versus diamond grid) than to the size of the numerical time step.