Present Status of the Nd:YAG Thomson Scattering System Development for Time Evolution Measurement of Plasma Profile on Heliotron J

A new high repetition rate Nd:YAG Thomson scattering system is developed for the Heliotron J helical device.A main purpose of installing the new system is the temporal evolution measurement of a plasma profile for improved confinement physics such as the edge transport barrier (H-mode) or the internal transport barrier of the helical plasma.The system has 25 spatial points with ～10mm resolution.Two high repetition Nd:YAG lasers (>550mJ@ 50Hz) realize the measurement of the time evolution of the plasma profile with ～10ms time intervals.Scattered light is collected by a large concave mirror (D=800 mm,f/2.25) with a solid angle of ～100 mstr and transferred to interference filter polychromators by optical fiber bundles in a staircase form.The signal is amplified by newly designed fast preamplifiers with DC and AC output,which reduces the low frequency background noise.The signals are digitized with a multi-event QDC,fast gated integrators.The data acquisition is performed by a VME-based system operated by the CINOS.     

Activation of Mast-Cell-Derived Chymase in the Lacrimal Glands of Patients with IgG4-Related Ophthalmic Disease

The purpose of this present study was to investigate the distribution and expression of chymase in the lacrimal glands (LGs) of patients afflicted with IgG4-related ophthalmic disease (IgG4-ROD). LGs from patients with severe canalicular obstruction were considered the control group. Toluidine blue staining confirmed a significant increase in the number of mast cells in the LGs obtained from the IgG4-ROD patients. In addition, immunostaining of serial sections from the LGs showed a significant increase in the number of chymase-positive cells and tryptase-positive cells in the IgG4-ROD LGs compared to the normal control LGs. The mRNA expression of chymase, tryptase, TGF-β1, and collagen-I tended to increase in the IgG4-ROD LGs. Immunostaining of vimentin and α-smooth muscle actin (α-SMA) showed that myofibroblasts were the main cellular components in severely fibrotic regions of LGs in patients with IgG4-ROD. Linear regression analyses on the number of mast cells, chymase-positive cells, and tryptase-positive cells revealed significant positive correlations between those respective cells. Our findings suggest that chymase may play a role in the fibrotic disorder of IgG4-ROD LGs through the regulation of TGF-β1 activation and collagen-I deposition, and that it may be a therapeutic target for patients afflicted with IgG4-ROD.     

Pathophysiological Roles of Actin-Binding Scaffold Protein,Ezrin

Ezrin is one of the members of the ezrin/radixin/moesin (ERM) family of proteins. It was originally discovered as an actin-binding protein in the microvilli structure about forty years ago. Since then, it has been revealed as a key protein with functions in a variety of fields including cell migration, survival, and signal transduction, as well as functioning as a structural component. Ezrin acts as a cross-linker of membrane proteins or phospholipids in the plasma membrane and the actin cytoskeleton. It also functions as a platform for signaling molecules at the cell surface. Moreover, ezrin is regarded as an important target protein in cancer diagnosis and therapy because it is a key protein involved in cancer progression and metastasis, and its high expression is linked to poor survival in many cancers. Small molecule inhibitors of ezrin have been developed and investigated as candidate molecules that suppress cancer metastasis. Here, we wish to comprehensively review the roles of ezrin from the pathophysiological points of view.     

On the separation in 2-period double round robin tournaments with minimum breaks

This paper considers the separation in 2-period double round robin tournaments (2P-DRRTs) with minimum breaks. The separation is a lower bound on the number of slots between the two games with the same opponents. None of known schemes provides 2P-DRRTs with minimum breaks and a positive separation. We first propose a new scheme to generate 2-separation 2P-DRRTs with minimum breaks, based on single round robin tournaments (SRRTs) with minimum breaks which have the last break in the third slot from the end. Our experiment results show that such SRRTs exist for 8-68 teams. Secondly, we consider maximizing the separation in general 2P-DRRTs with minimum breaks by integer programming and constraint programming, respectively. The two approaches of direct formulation and “first-break, then-schedule” decomposition are presented and compared. We obtain the maximum separation for up to 14 teams. Furthermore, we consider the application with place constraints to show the flexibility and efficiency of scheduling 2P-DRRTs with minimum breaks and a positive separation.     

Microstructural analysis of the stir zone of Al alloy produced by friction stir spot welding

The present study applied friction spot joining (FSJ), which was recently developed as a lap joining technique of Al alloys, to two sheets of Al alloy 6061, 1 mm in thickness, and then examined the microstructural feature in the weld. The weld had the nugget-shaped stir zone around the exit hole of the probe, and the stir zone exhibited the equiaxed grain structure having finer grain size than that of the base material. The crystallographic texture analysis using electron backscattered diffraction method suggested that the material movement occurred along the rotating direction of the welding tool in the wide region including the stir zone. In the periphery of the nugget-shaped stir zone, which was characterized as the region having the finer grain size than that of the stir zone interior, any inclusions and precipitates were not found in the SEM scale. The weld was softened around the weld centre. The softening could be explained by dissolution and/or growth of the strengthening precipitates due to thermal cycle of FSJ.     

Proposal for a benchmark model of a laminated iron core and a large‐scale and highly accurate magnetic analysis

This paper describes a benchmark model proposed for the clarification of the characteristic of various methods for modeling the laminated iron core. In order to obtain a reference solution of the benchmark model, a large‐scale nonlinear magnetostatic field analysis with a mesh fine enough to represent the microscopic structure of the laminated iron core is carried out by using the hybrid finite element–boundary element (FE‐BE) method combined with the fast multipole method (FMM) based on diagonal forms for translation operators. The computational costs and accuracy of two kinds of homogenization methods are discussed, comparing them with the reference solution. As a consequence, it is verified that the homogenization methods can analyze magnetic fields in laminated iron core within acceptable computational costs. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(1): 26–35, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20809     

A new method for estimating initial rotor phase of self‐excited hybrid‐field synchronous motors

This paper proposes a new method for properly estimating the rotor initial phase (i.e., the position) of the newly emerging self‐excited hybrid‐field synchronous motors (SelE‐HFSMs), which have the rotor held by both a permanent magnet and a diode‐shorted held winding. The proposed method injects a spatially rotating high‐frequency voltage and detects the rotor phase directly by evaluating the norm of the associated current. The method is very simple, but has a high degree of usability. 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(3): 49–58, 2010; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.21027     

Characteristics of plasma produced by MHD technology and its application to propulsion systems

This paper analyzes plasma characteristics for the newly proposed concept of a closed-loop MHD power generation combined cycle system, which is used as a pulse-driven MHD accelerator to accelerate plasma to high velocity, with a nuclear plant. In this paper, since the final goal is for the space propulsion system applications, the performance of a MHD acceleration system is also analyzed by the Q1D analysis program. Results reveal that the radial velocity with the MHD effect is accelerated rapidly at the channel exit, with a calculated maximum velocity of about 4700 m/s. Consequently, specific impulse approximately 480 s and thrust of about 6550 N are estimated. The static gas temperature is evaluated at less than 600 K, while the value of about 1800 K is calculated for the stagnation gas temperature in the MHD channel.     

“Disturbance observers in D‐module” for sensorless drive of synchronous motors—new phase estimation with zero phase lag

This paper proposes two new “disturbance observers in the D‐module” for sensorless drive of synchronous motors including permanent‐magnet synchronous motors and synchronous reluctance motors. The disturbance filter for the observers can estimate speed‐varying rotor phase (in other words, rotor position) with zero phase lag. It is constructed by means of “the filter in the D‐module,” which has the following desired characteristics for variable sensorless drive: (1) it makes distinction between positive and negative frequencies of two‐phase signals; (2) it can allow processing of the signals based on frequency polarities; (3) it can also change dynamically its center frequency of bandpass filtering according to rotor speed estimates; (4) its passband and transition can be designed independently; and (5) it can be easily realized. The new disturbance observers also have a generality such that they contain the recently proposed disturbance observer as a special case. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(3): 63–70, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20602     

Investigation of electron trapping behavior in n-channel organic thin-film transistors with ultrathin polymer passivation on SiO2 gate insulator

Electron trapping behavior at the interface between N,N′-ditridecyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C13) film and thermal SiO₂ was investigated by utilizing ultrathin poly(methyl methacrylate) (PMMA) gate passivation layers. From the capacitance–voltage analysis for the PTCDI-C13/PMMA/SiO₂ interface, it is found that the electron tunneling appeared with PMMA thinner than 0.8 nm, and that the thickness of the gate passivation layer should be at least 1 nm for preventing injection-type hysteresis in the capacitance–voltage curve. The effective electron mobility of organic thin-film transistors (OTFTs) based on PTCDI-C13 with SiO₂ gate insulator was increased by suppressing shallow-level interface traps on SiO₂ with the PMMA layer, which can be partially accounted for by the multiple trap and release model. In this work, the thickness and the density of the PMMA layers were precisely controlled with a simple spin-coating process. Even 1.3-nm thick PMMA layer caused the improvements of the electron mobility and the air stability of the n-channel conduction.