Ethanol Conversion on MCM-41 and FSM-16, and on Ni-Doped MCM-41 and FSM-16 Prepared without Hydrothermal Conditions

MCM-41 and FSM-16 were both prepared using no hydrothermal conditions, and nickel was doped into these catalysts (Ni-MCM-41 and Ni-FSM-16) using a template ion exchange method. FSM-16 and Ni-FSM-16 had greater catalytic activity for the conversion of ethanol than MCM-41 and Ni-MCM-41, indicating that FSM-16 has potential as a catalyst for the conversion of ethanol to propylene.     

Transformation and fragmentation behavior of molten metal drop in sodium pool

In order to clarify the fragmentation mechanism of a metallic alloy (U–Pu–Zr) fuel on liquid phase formed by metallurgical reactions (liquefaction temperature = 650 °C), which is important in evaluating the sequence of core disruptive accidents for metallic fuel fast reactors, a series of experiments was carried out using molten aluminum (melting point = 660 °C) and sodium mainly under the condition that the boiling of sodium does not occur. When the instantaneous contact interface temperature (T_i) between molten aluminum drop and sodium is lower than the boiling point of sodium (T_c,bp), the molten aluminum drop can be fragmented and the mass median diameter (D_m) of aluminum fragments becomes small with increasing T_i. When T_i is roughly equivalent to or higher than T_c,bp, the fragmentation of aluminum drop is promoted by thermal interaction caused by the boiling of sodium on the surface of the drop. Furthermore, even under the condition that the boiling of sodium does not occur and the solid crust is formed on the surface of the drop, it is confirmed from an analytical evaluation that the thermal fragmentation of molten aluminum drop with solid crust has a potential to be caused by the transient pressurization within the melt confined by the crust. These results indicate the possibility that the metallic alloy fuel on liquid phase formed by the metallurgical reactions can be fragmented without occurring the boiling of sodium on the surface of the melt.     

Transport of human immunoglobulin G and Fc-fusion proteins to chicken egg yolk

We examined the transport of human immunoglobulin G (IgG) subclasses and fusion proteins with the Fc region of human IgG to the egg yolk, after the proteins were injected into a vein of hens. Human IgGs were efficiently transported and accumulated into the yolk, whereas the proteins were not detected in the egg white. Among human IgG subclasses, IgG2 was transported most efficiently. Fc-fusion proteins injected were also transported into the yolk. A fusion protein with the Fc region derived from human IgG2 was more efficiently transported into the yolk than the counterpart fusion with the Fc region from human IgG1. This study shows that the recovery of recombinant antibodies and Fc-fusion proteins from the yolk is an effective method in transgenic chicken bioreactors.     

Determination of optimal motion of tools in metal forming processes by controlled FEM simulation

A method for determining optimal motion of tools in metal forming processes from the finite element simulation is proposed. In this method, the calculated results such as the deforming shape and the stress and strain distributions are monitored in each deformation step of the finite element simulation, and the forming motion of tools is iteratively optimized on the basis of a feedback control referring to the monitored results. The present method is applied to determination of the motion of rolls for forming plates into desired curvatures in plane-strain three-roll bending. Fuzzy reasoning is used to obtain the movement of the top roll in each deformation step, and the effects of the plate thickness and the difference between the desired and the calculated curvatures are taken into consideration. To avoid the delay of the control, the effect of the curvature distribution during bending is included in the fuzzy reasoning. It is shown that decrease in the curvature near both ends of the bent plate in three-roll bending is prevented by the use of the present method.     

Catalytic dehydrochlorination of 1,2-dichloroethane into vinyl chloride over polyacrylonitrile-based active carbon fiber

Dehydrochlorination of 1,2-dichloroethane (1,2-DCE) into vinyl chloride (VC) was carried out over polyacrylonitrile-based active carbon fibers (PAN-ACFs). PAN-ACFs showed excellent catalytic activity, although the lifetime was not sufficiently long enough for practical application. X-ray photoelectron spectroscopy (XPS) revealed that the active site was pyridinic nitrogen and that chlorine stayed on the surface after the reaction. Coke was also produced in the pores, as suggested by the weight increase. The heat-treatment after the reaction released hydrogen chloride from the ACF, but no catalytic activity was restored. The preheat-treatment was found to shorten the catalytic lifetime.

An optimum temperature and uniform distribution in the catalyst bed achieved by this fluidized bed may provide a practical process of sufficient life.     

Production of anti-CD2 chimeric antibody by recombinant animal cells

Expression vectors for chimeric anti-CD2 antibody were constructed in order to clarify the importance of the expression ratio of heavy (H-) and light (L-) chains of antibody to antibody production in animal cells. The antibody genes were introduced into cells using plasmid DNA vectors or replication-defective retroviral vectors. Productivity was maximal when the expression ratio of H-and L-chains was 1:1, and decreased when the ratio was not equal. We also examined the expression of antibody using one-packed vectors in which the bicistronic expression of H- and L-chain genes was mediated by an internal ribosomal entry site (IRES) sequence derived from encephalomyocarditis virus (EMCV). The translation efficiency was unbalanced between 5'Cap- and IRES-dependent genes. Using the retroviral vectors, it was estimated that the IRES-dependent translation efficiency was 5-fold lower than the 5'Cap-dependent translation efficiency. The cells exhibiting an unbalanced expression of H- and L-chains tended to accumulate H-chain protein.     

Prediction of fracture in sintering of ceramic powder compact

A criterion for predicting fracture initiation due to non-uniform shrinkage in sintering of ceramic powder compacts is proposed. In the present criterion, the occurrence of sintering fracture is evaluated by using the difference in volumetric strain between non-uniform and uniform shrinkages because the stress is induced by the difference in volumetric strain during sintering. The material constants in the criterion are determined from a sintering test using ringed compacts under restriction of the shrinkage. Non-uniform shrinkage behaviour due to the density distribution in sintering of circular plates and rings with a boss is simulated by the viscoplastic finite element method, and the occurrence of sintering fracture is predicted from the calculated results by the use of the criterion. The predicted fracture rates and sites for the sintered products are in good agreement with the experimental ones for alumina compacts.     

Dissolution of platinum in acidic media

To understand the degradation of the Pt/C cathode for use in polymer electrolyte fuel cells, the solubility and the dissolution mechanism of platinum in acidic media was very important fundamentally. In this study, the platinum solubility has been determined in acidic electrolytes as a function of temperature and pH. The solubility was 3 × 10^?6 mol dm^?3 at 25 °C in 1 mol dm^?3 of H₂SO₄, HClO₄, and CF₃SO₃H under air. It increased at higher temperature and decreased in pH. The apparent enthalpy of the dissolution reaction was ca. 25 kJ mol^?1, and the solubility was proportional to [H⁺] in these acids. The platinum solubility in oxygen was slightly higher than that in air. The detected dissolved Pt species was 4 valent. On the other hand, the solubility of platinum in nitrogen was much lower than the oxygen-containing atmosphere. Based on these results, the platinum solubility in an oxygen-containing atmosphere would mainly be the following acidic dissolution reaction: PtO₂ + H⁺ + H₂O = Pt(OH)₃⁺.     

Engineering Dirac electrons emergent on the surface of a topological insulator

The concept of the topological insulator (TI) has introduced a new point of view to condensed-matter physics, relating a priori unrelated subfields such as quantum (spin, anomalous) Hall effects, spin–orbit coupled materials, some classes of nodal superconductors, superfluid ³He, etc. From a technological point of view, TIs are expected to serve as platforms for realizing dissipationless transport in a non-superconducting context. The TI exhibits a gapless surface state with a characteristic conic dispersion (a surface Dirac cone). Here, we review peculiar finite-size effects applicable to such surface states in TI nanostructures. We highlight the specific electronic properties of TI nanowires and nanoparticles, and in this context we contrast the cases of weak and strong TIs. We study the robustness of the surface and the bulk of TIs against disorder, addressing the physics of Dirac and Weyl semimetals as a new research perspective in the field.