Fundamental Evaluation of Power Supply and Rectifiers for Wireless Power Transfer Using Magnetic Resonant Coupling

This paper provides a fundamental analysis of a power supply and rectifiers for wireless power transfer using magnetic resonant coupling (MRC). MRC enables efficient wireless power transfer over middle‐range transfer distances. MRC for wireless power transfer should operate at a high frequency in the industry science medical band, such as 13.56 MHz, because the size of the transfer device decreases at higher transfer frequencies. Therefore, the output frequency of the power supply on the transmitting side should be 13.56 MHz. In addition, the rectifier on the receiving side is operated at a high frequency. This paper focuses on the reflected power in the power supply and rectifiers. Thus, the parametric design method is clarified for the power supply, including a low‐pass filter to match the output, the impedance of the power supply with the characteristic impedance of the transmission line. In addition, the effects on the rectifiers of silicon carbide and gallium nitride diodes are confirmed by performing an experiment and a loss analysis.     

A redundant multivalued logic for a 10-Gb/s CMOS demultiplexer IC

A redundant multivalued logic is proposed for high-speed communication ICs. In this logic, serial binary data are received and converted into parallel redundant multivalued data. Then they are restored into parallel binary data. Because of the multivalued data conversion, this logic makes it possible to achieve higher operating speeds than that of a conventional binary logic. Using this logic, a 1:4 demultiplexer (DEMUX, serial-parallel converter) IC was fabricated using a 0.18-/spl mu/m CMOS process. The IC achieved an operating speed of 10 Gb/s with a supply voltage of only 1.3 V and with power consumption of 38 mW. This logic may achieve CMOS communication ICs with an operating speed several times greater than 10 Gb/s.     

Studies on chitin. IX. Crosslinking of water-soluble chitin and evaluation of the products as adsorbents for cupric ion

Water-soluble chitin was successfully crosslinked to varying extents with glutaraldehyde in homogeneous aqueous solutions to improve the properties as an adsorbent for metal cations, and the effects of crosslinking were discussed. Complete insolubilization was achieved with the fivefold excess aldehyde, but, in terms of adsorptivity of Cu²⁺, the chitin crosslinked at an aldehyde/amino group ratio of 1.0 was found to exhibit remarkable capacity and was much superior to others. The desorption of Cu²⁺ from the adsorption complex was also attained effectively at pH 2.0. These results indicated that the loose crosslinking was quite simple and efficient to produce high capacity adsorbents for practical use. Thermal behavior of the crosslinked chitin was examined by TMA and TGA; a softening phenomenon was observed at 145°C.     

Mechanical properties of SiNxCx ceramic films prepared by plasma CVD

The mechanical properties of Si₃N₄-SiC, SiN_x and SiC_y films prepared at a low temperature of 400 °C by plasma chemical vapour deposition are reported. Microhardness, internal stress of the film and adhesive strength between the film and glass or stainless steel substrate were evaluated as principal mechanical properties. Microhardness was measured to be about 10 to 20 G Pa dependent on the film composition in each system. Internal stress of the films on borosilicate glass substrates extensively varied from tensile to compressive with the film composition change from Si₃N₄ to SiC. Adhesive strength, as ascertained by the scratch test, was about 580 to 800 MPa for crown glass substrates, and about 210 to 310 M Pa for 316 stainless steel substrates. It is pointed out that tensile stress in these films brought about more abrupt decreases of the adhesive strength than did compressive stress.     

Comfort limits for asymmetric thermal radiation

Groups of 32 and 16 subjects of both sexes were exposed in an environmental chamber to radiant asymmetry caused by a cool wall, a warm wall, and a cool ceiling. Each subject was tested individually while seated and clothed at 0.6 clo. During each 3.5-hour experiment the subject was exposed to six radiant temperature asymmetries. He was asked whether and where he experienced any local cool or warm sensation, and whether it was felt to be uncomfortable. During the entire experiment he was kept thermally neutral by changing the air temperature according to his wishes.For cool walls, warm walls, and cool ceilings curves have been established showing the percentage of dissatisfied subjects as a function of the radiant asymmetry. Radiant asymmetry at a warm wall caused less discomfort than a cool wall. A cool ceiling caused less discomfort than a warm ceiling. Accepting that 5% of the subjects may feel uncomfortable. a radiant temperature asymmetry of 10°C is allowable at a cool wall, 23°C at a warm wall, and 14°C under a cool ceiling. A previous study showed that 4°C is allowable under a warm ceiling. Radiant asymmetry had no significant impact on the operative temperatures preferred by the subjects. No significant differences were observed between the responses of men and women exposed to radiant asymmetry.     

Practical method for generation expansion planning based on dynamic programming

This paper presents an efficient method which provides the optimal generation mix and the optimal generation construction process. The approximation method in which the dynamic programming technique and gradient method are combined is applied to determine the optimal generation mix with hydropower generation technologies. The successive approximations dynamic programming (SADP) technique, which is very suitable for high-dimensional multistage decision process problems, is used for obtaining the optimal generation construction process. The effectiveness and feasibility of the developed technique are demonstrated on a practical power system model which has five types of generation technologies including a hydropower generation technology.     

Mechanical alloying in the Al-Bi alloy system

Mechanical alloying (MA) was carried out to investigate the MA behaviour of the immiscible Al-10, 30 at % Bi alloys. After the MA processing, the Al and Bi were finely and homogeneously alloyed. The Bi crystallite size decreased to 25 nm and 30 nm in the Al-10 at % Bi and Al-30 at % Bi alloys, respectively. By increasing the MA time, the hardness increased up to a value of 80 H _v, which is larger than that obtained from the rule of mixtures. The lattice parameter of Bi decreased by about 0.27%, which shows the formation of a non-equilibrium hcp Bi super-saturated solid solution. The extended solubility of Al in Bi was 1.9% in the Al-30 at % Bi alloy. Due to the extended solubility, depression of the melting temperature of hcp Bi was confirmed in the mechanically alloyed Al-Bi alloys. The maximum depression in the temperature was about 10 K. The measured values corresponded well with those estimated from the extrapolation of the solidus line.     

A case of macrocystic cervical neurinoma diagnosed by MRI with Gd-DTPA

The authors report a rare case of a large cystic cervical neurinoma. A 45-year-old female was admitted to our clinic because of motor weakness of the right upper extremity, numbness of the right fingers and right posterior cervical pain. Metrizamide CT myelography demonstrated the outline of a low density mass. MRI showed a mass revealing low signal intensity on T1-weighted image, high signal intensity on T2-weighted image and marginal enhancement on contrast image with Gd-DTPA. The mass which was diagnosed as cystic tumor, was located in the intradural extramedullary space between C4 to C5 segments. After C4 through C5 laminectomy, the tumor was found to originate from the C5 anterior motor root. The tumor consisted mostly of a cystic part with a very thin solid compartment beneath the capsule. Postoperative course of the patient was uneventful. Although spinal neurinoma is one of the most common spinal tumors, an almost completely degenerated large cystic spinal neurinoma is extremely rare. MRI with Gd-DTPA was useful for the diagnosis of the cystic neurinoma by clearly enhancing the margin of the tumor.     

Effects of macrophage colony-stimulating factor (M-CSF) on lipopolysaccharide (LPS)-induced mediator production from monocytes in vitro

M-CSF is a macrophage-lineage-specific growth factor that causes proliferation and differentiation of progenitor cells in the bone marrow. To investigate the effects of M-CSF on more matured cells, human monocytes were cultured in the presence or absence of M-CSF for 6 days. Addition of M-CSF at more than 10(2) U/ml resulted in higher viability and caused morphological differentiation to large macrophage-like cells. LPS-induced mediator production was also compared between M-CSF-treated and control cell. Monocytes were incubated with or without M-CSF for 3 days, and were stimulated with 1 microgram/ml of LPS for 2 days. IL-1 beta was not detected in the both culture supernatants, and PGE2 production was not influenced by M-CSF. However, amounts of G-CSF, GM-CSF, IL-6, and TNF-alpha produced in response to 1 microgram/ml of LPS were 1.5 to 2 times greater from monocytes treated with 10(4) U/ml of M-CSF than from control cells. The priming effect of M-CSF on LPS-induced cytokine production was found to require 3-day preincubation, and reached a maximum at the concentration of 10(4) U/ml. M-CSF-treated cells responded to a 10 times lower concentration of LPS than control cells in terms of cytokine production. M-CSF was also shown by flowcytometric analysis to influence the expression of CD14, a receptor for LPS, which might render monocytes more sensitive to LPS.     

Recovery retardation in equal channel angular pressed Al–Zr alloy during friction stir welding

The effect of Zr on reduction of hardness and microstructure in an FS weld of equal channel angular-pressed Al alloy was investigated. Zr addition to Al suppressed dynamic recovery in the thermomechanically affected zone and enabled retention of the high hardness of the ECA-pressed material throughout the weld.