Fabrication of Lotus-Type Porous Carbon Steel Slabs by Continuous Casting Technique in Nitrogen Atmosphere

Lotus-type porous carbon steel slabs with long cylindrical pores aligned in one direction were fabricated by the continuous casting technique in a mixture gas of N₂ 0.8 MPa and Ar 1.7 MPa or in N₂ 2.5 MPa at various transfer velocities from 2.5 mm·min⁻¹ to 20 mm·min⁻¹. The pore size in lotus carbon steel fabricated in the mixture gas of nitrogen and argon was small and homogeneous, whereas the pore size in nitrogen had bimodal distribution depending on the transfer velocity. The large pores were observed mainly at the edge of the slab, which are considered to be merged of several inclined pores. The porosity depended on nitrogen partial pressure, which is explained by Sieverts’ law. The hardness of lotus carbon steel matrix increased, which was attributed to the solid-solution of nitrogen.     

A new undulator scheme providing various polarization states with low on-axis power density

A new undulator scheme is proposed to enable flexible utilization of polarization properties of synchrotron radiation, which is based on the composite-period undulator originally proposed to improve the wavelength tunability of free electron lasers. It has an advantage over the conventional undulators that the on-axis power density is kept low even when a high K value is applied to lower the photon energy. The basic principle and availability of various polarization states are presented together with a practical example.     

MMIC development for millimeter-wave space application

The latest millimeter-wave monolithic-microwave integrated-circuit (MMIC) developments and technologies at the Mitsubishi Electric Corporation, Kanagawa, Japan, concerning high power amplifiers, low-noise amplifiers and phase shifters have been summarized. It has been shown that high-efficiency, low-noise, and low-loss performance for millimeter-wave space applications can be achieved by employing pseudomorphic high electron-mobility transistor (p-HEMT) MMIC technology. The investigation for gamma-ray irradiation hardness has cleared that millimeter wave p-HEMT MMICs have over a 100 years of life against gamma-ray irradiation in the space environment     

Effect of microstructure on the fatigue behavior of aluminum titanate ceramics

The effect of microstructures, such as grain size and internal pores, on the fatigue behavior of aluminum titanate (AT, Al₂TiO₅) ceramics was investigated at room temperature and 973 K. When the average grain size of the AT ceramics was decreased from 22 to 13 μm, the flexural strength was approximately doubled at both temperatures. The decrease in the grain size is considered to reduce the size and amount of microcracks present at the grain boundaries. Fatigue deterioration of the ceramics was accelerated by applying cyclic stress. The cyclic fatigue behavior of the ceramics with smaller grains suggested control by a “grain bridging degradation mechanism” at both temperatures. However, that of the ceramics with larger grains was governed by the fatigue mechanism, depending on the testing temperatures. There was little effect from internal pores on the cyclic fatigue behavior of the AT ceramics at room temperature. On the other hand, at 973 K, the lifetime of the cyclic fatigue was decreased due to the presence of pores.     

A Non-Scan Approach to DFT for Controllers Achieving 100% Fault Efficiency

This paper presents a non-scan design-for-testability method for controllers that are synthesized from FSMs (Finite State Machines). The proposed method can achieve complete fault efficiency: test patterns for a combinational circuit of a controller are applied to the controller using state transitions of the FSM. In the proposed method, at-speed test application can be performed and the test application time is shorter than previous methods. Moreover, experimental results show the area overhead is low.     

Endoscopic harvesting of the radial artery as a coronary artery bypass graft

With an endoscopic approach we harvested the radial artery as a coronary artery bypass graft, using two transverse 2-cm incisions in the forearm. There were no complications in the forearm and hand. The short-term results of the radial artery graft were good.     

Binding of mitochondrial presequences to yeast cytosolic heat shock protein 70 depends on the amphiphilicity of the presequence

The interactions between a yeast cytosolic hsp70, Ssa1p, and various synthetic peptides, including mitochondrial presequences, have been studied. The interactions were monitored both indirectly, by measuring the effects of the presequences on the ATPase activity and oligomeric state of the enzyme, and directly, by measuring the increased steady-state fluorescence polarization of fluorescent derivatives of the presequences as they bind to Ssa1p. The presequences are all able to convert Ssa1p from an oligomeric to a monomeric form in a concentration-dependent manner. The presequences are also able to stimulate the ATPase activity of the enzyme at similar concentrations. Quantification of the binding by fluorescence polarization showed that the affinity for Ssa1p is directly related to the physical properties of the presequences. The most amphiphilic presequences, as measured by retention times on reversed-phase high pressure liquid chromatography or surface activity in lipid monolayers, had the highest affinity for Ssa1p. The least amphiphilic presequences, which had previously been shown to be ineffective as mitochondrial targeting sequences, had relatively low affinity for Ssa1p. The results show that Ssa1p interacts with a broad range of amino acid sequences and that the strength of these interactions is related to the physical properties of the sequence. That the physical properties recognized by Ssa1p are identical to those necessary for the targeting function of mitochondrial presequences suggests that Ssa1p may interact with mitochondrial precursor proteins in the cytosol. The interactions may serve a variety of purposes: the maintenance of precursors in translocation-competent forms, the prevention of improper association of precursors with non-mitochondrial membranes, and the delivery of precursors to the mitochondrial surface.