Novel FDTD simulation method using multiple-analysis-space for electromagnetic far field

Wide-band undesired electromagnetic noise near electronic systems, which includes small noise source like the printed circuit board (PCB), is a current problem in the field of electromagnetic interference. However, the estimation method for the electromagnetic noise near a system under test has not been established. This paper proposes a newly developed estimation method of the electromagnetic noise for a wide area, from near to far field, using the finite difference time-domain (FDTD) method. The proposed FDTD simulation method is an estimation technique for near to far field with multiple analysis spaces (MAS). The MAS has an internal analysis space (IAS) and an external analysis space (EAS). The analysis near a radiation source can be calculated in the IAS. The EAS is the outside space from IAS, which is for calculation of the far field. It is expected that the proposed FDTD method by MAS (FDTD-MAS) decrease in the calculation cost in terms of computational time and memory costs, especially for estimation of radiation from PCB. The principle procedure of the FDTD-MAS method is described in the first part of this paper. As example of advantages of the calculation and confirmation of the calculation accuracy, the electric field distributions radiated from a 1-GHz half-wavelength dipole antenna in an IAS of 0.3/spl times/0.3 m/sup 2/ area and an EAS of 7/spl times/7 m/sup 2/ area are used as examples. When the cell size ratio of IAS to EAS is changed from 6 to 20, the FDTD and theoretical values show good agreement. It is indicated that the FDTD-MAS simulation method is one of the most powerful tools for the estimation of electromagnetic noise from near field to far field from small and thin source.     

Titanium Phosphate Glass-Ceramics with Silver Ion Exchangeability

Na₂O-CaO-TiO₂-P₂O₅ glass-ceramics containing Nasicon-type crystals were found to have silver-ion exchangeability. The Nasicon-type phase contains Ca²⁺ and Na⁺ ions which are located in two different sites of the conduction channels: the Na⁺ ions with high mobility can be exchanged easily with Ag⁺ ions in aqueous solution. The Ag⁺-ion-exchanged glass-ceramics showed excellent bacteriostatic activity and a relatively high strength of 160 MPa in bending.     

Characterization of deformation-induced metallurgical change in austenite stainless steel sheet with acoustic microscopy

This article reports on the non-destructive evaluation (NDE) of metallurgical changes induced by the deformation processes. In particular, the martensite and reversed austenite states of a meta-stable austenitic stainless steel sheet were evaluated. The sheet was elongated up to 40% at room temperature, and was then brought below room temperature to produce martensite. This was then followed by annealing for reversion. First, martensite content was measured with a Feritscope. Second, the surface acoustic wave (SAW) velocity was measured with a high numerical aperture spherically focused ultrasonic beam with a frequency equal to 600 MHz. The measured SAW velocity values were found to be dependent on the elongation, the ambient temperature during elongation, and the annealing temperature. A useful trend was found in the correlation between the measured SAW velocity and the martensite content as measured with the Feritscope. Second, using a high frequency (i.e., 800 MHz) acoustic imaging technique, the deformed and annealed grain structures were mapped. In comparing the acoustic images with the optical images, the deformed grains shown in the acoustic images were found to be significantly clearer than those shown in the optical images. These studies reveal the importance of NDE, in connection with the forming of stainless steel structures, to map the deformation induced metallurgical changes. Here, unique NDE techniques are seen to be effective in mapping the changes with the use of hypersonic SAW velocity measurements and imaging.     

Induction of hydroxycarbonate apatite formation on polyethylene or alumina substrates by spherical vaterite particles deposition

Hydroxycarbonate apatite (HCA) layers were formed on polyethylene (PE) or alumina substrates by depositing spherical sub-micron vaterite particles and then immersing in simulated body fluid (SBF). HCA formation on vaterite‐coated PE was faster than that on coated alumina (3 days for PE and 7 days for alumina). The adsorption of phosphate ions on the vaterite particles in SBF was studied by monitoring changes in the concentration of phosphorous in SBF and the surface charges of vaterite during the SBF immersion. The phosphorous concentration of SBF in which a vaterite-coated PE was immersed for 1 h was lower than that in which a vaterite-coated alumina was immersed. Zeta potential of the vaterite surface deposited on PE drastically decreased after 1 h immersion in SBF. The vaterite particles deposited on each substrate immediately adsorbed phosphate ions in SBF. The amount of ions adsorbing on the vaterite surfaces deposited on PE was larger than that on alumina. This was attributed to differences in the surface charges between PE (? 16 mV) and alumina (+ 38 mV). The phosphate adsorption was predominantly electrostatic therefore related to the surface charge of vaterite particles. The surface charges of substrates may affect the charge of vaterite particles.     

Joining of Calcium Phosphate Invert Glass-Ceramics on a β-Type Titanium Alloy

A bioactive calcium phosphate invert glass-ceramic containing β-Ca₃(PO₄)₂ crystals could be joined strongly with a Ti–29Nb–13Ta–4.6Zr alloy consisting of a β-titanium phase by heating the metal on which the mother glass powders with a composition 60CaO·30P₂O₅·7Na₂O·3TiO₂ (mol%) were placed, at 800°C for 1 h in air; the tensile joining strength was estimated to be ∼26 MPa on average. A compositionally gradient layer was developed on the metallic substrate during the heating. When the metal with glass powders on it was heated at 850°C in air, the phosphate glassy phase flowed viscously, permeating the oxide layer formed around the surface of the metal, which was thicker than that formed by heating at 800°C; a compositionally gradient layer was not developed, and a strong joining was not realized. The joining between the glass-ceramic and the metal is suggested to be controlled by viscous flow of the glassy phase in the glass-ceramic and by reaction of the glassy phase with the oxide phase formed around the surface layer of the metal.     

Inhibition of insulin-induced GLUT4 translocation by Munc18c through interaction with syntaxin4 in 3T3-L1 adipocytes

Insulin induces the translocation of vesicles containing the glucose transporter GLUT4 from an intracellular compartment to the plasma membrane in adipocytes. SNARE proteins have been implicated in the docking and fusion of these vesicles with the cell membrane. The role of Munc18c, previously identified as an n-Sec1/Munc18 homolog in 3T3-L1 adipocytes, in insulin-regulated GLUT4 trafficking has now been investigated in 3T3-L1 adipocytes. In these cells, Munc18c was predominantly associated with syntaxin4, although it bound both syntaxin2 and syntaxin4 to similar extents in vitro. In addition, SNAP-23, an adipocyte homolog of SNAP-25, associated with both syntaxins 2 and 4 in 3T3-L1 adipocytes. Overexpression of Munc18c in 3T3-L1 adipocytes by adenovirus-mediated gene transfer resulted in inhibition of insulin-stimulated glucose transport in a virus dose-dependent manner (maximal effect, approximately 50%) as well as in inhibition of sorbitol-induced glucose transport (by approximately 35%), which is mediated by a pathway different from that used by insulin. In contrast, Munc18b, which is also expressed in adipocytes but which did not bind to syntaxin4, had no effect on glucose transport. Furthermore, overexpression of Munc18c resulted in inhibition of insulin-induced translocation of GLUT4, but not of that of GLUT1, to the plasma membrane. These results suggest that Munc18c is involved in the insulin-dependent trafficking of GLUT4 from the intracellular storage compartment to the plasma membrane in 3T3-L1 adipocytes by modulating the formation of a SNARE complex that includes syntaxin4.     

The relationship between multiple intrathyroidal involvement in papillary thyroid carcinoma and chronic non-specific thyroiditis

The relationship between multiple intrathyroidal involvement (MII) and chronic non-specific thyroiditis (CT) was investigated in 69 papillary thyroid carcinoma patients who received a subtotal or total thyroidectomy. The overall incidence of MII in patients with CT and the incidence of MII in the affected lobe of the patients with CT were significantly higher than that without CT (P = 0.0012 and 0.0425, respectively). Because Hashimoto's thyroiditis is believed not to carry the increased risk of associated thyroid malignancy, the high incidence of MII in the affected lobe in the case with CT is postulated to be caused by intraglandular metastases.