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21.
Fujihiko Matsumoto Ayako Miyake Yasuaki Noguchi 《International Journal of Electronics》2013,100(1):71-78
A current mirror circuit is widely utilized as an important building block in analogue signal processing circuits. This paper describes a high-precision low voltage bipolar current mirror circuit. Well known current mirror circuits, such as a simple current mirror and a Wilson current mirror, have a trade-off between low-voltage operation and accuracy of the current gain. The accuracy of the proposed current mirror is high in spite of low current amplification factor (β) of transistors and large current output (or a large number of the multiple output). The current mirror circuit can operate at a 1V or less supply voltage. The high accuracy is realized by negative current feedback with high gain. Thus, the stability of the circuit and compensation methods are discussed. PSPICE simulation shows that the proposed current mirror circuit compensated using Miller components composed of a capacitor and a resistor is stable and can operate at a 1V supply voltage. 相似文献
22.
Ayako Sakai Yoko Yamakoshi Naoki Miyata 《Fullerenes, Nanotubes and Carbon Nanostructures》1999,7(5):743-756
Cell transformation in vitro is a model of carcinogenesis in vivo. Two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. [60]Fullerene (C60) was cytotoxic in BALB/3T3 cells when it was irradiated by visible light, but not without light irradiation. Under conditions when C60 was cytotoxic, it acted as an initiating agent for cell transformation, but it did not act as a complete transforming agent. the initiating activity of visible-light-irradiated C60 was statistically significant in a modified two-stage transformation assay including a procedure for replating cells treated by C60 and light, but it was equivocal in the standard two-stage transformation assay. 相似文献
23.
Hiroshi Kawanabe Kiyoshi Kawasaki Toshio Seno Chihiro Kondo Masahiro Shioji 《亚洲传热研究》2007,36(5):303-313
The flow and mixing process of unsteady jets are fundamentally analyzed by large eddy simulations. The effects of nozzle velocity and turbulence intensity on the turbulent eddy structure and mixing process between the nozzle fluid and ambient fluid were investigated. The results show that a toroidal‐shaped vortex, which emerges around the jet tip, primarily accelerates the entraining flow. Also, increasing the turbulence intensity in the nozzle encourages mixing in the jet without changing the jet‐contour. Furthermore, when the rise‐up time of the initial nozzle velocity is elongated, turbulent mixing is suppressed. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(5): 303–313, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20158 相似文献
24.
The effect of humidity during storage on the crosslinking reactions of isocyanate groups was investigated with attenuated total reflectance Fourier transform infrared spectroscopy with pressure‐sensitive adhesives composed of poly[ethyl acrylate‐co‐(2‐ethylhexyl acrylate)‐co‐(2‐hydroxyethyl methacrylate)] as a base resin and polyisocyanate as a crosslinker. A peak‐resolving analysis of the amide II region revealed four bands. According to an analysis of the Fourier transform infrared spectra of the model compounds, these four bands were assigned to free urethane linkages, hydrogen‐bonded urethane linkages, free urea linkages, and hydrogen‐bonded urea linkages. As expected, storage under humid conditions led to the formation of free and hydrogen‐bonded urea linkages corresponding to the promotion of isocyanate consumption. Peak resolution of the amide II region was found to be a reasonable way of monitoring urethane and urea linkages during crosslinking reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3039–3045, 2003 相似文献
25.
Wang P Behan G Kirkland AI Nellist PD Cosgriff EC D'Alfonso AJ Morgan AJ Allen LJ Hashimoto A Takeguchi M Mitsuishi K Shimojo M 《Ultramicroscopy》2011,111(7):877-886
Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. 相似文献
26.
Rats were fed a diet supplemented with corn oil (n-3 deficient), soy oil, or a mixture containing 8% 22∶6n-3 ethyl ester for
6 wk. The hepatic capacities for the β-oxidation and synthesis of 22∶6n-3, in addition to the acylation of lysophosphatidate,
were tested in vitro. In rats that were fed a 22∶6n-3-enriched diet, both the β-oxidation of 22∶6n-3 and elongation of 20∶5n-3 were enhanced compared
to those in rats fed the other diets. Acylation of lysophosphatidate was also enhanced in rats fed a 22∶6n-3-enriched diet,
while the rate of dephosphorylation of phosphatidate was not changed. The amount of 22∶6n-3 in the liver was much less than
that consumed in a docosahexaenoic acid-enriched diet. These results suggest that a significant amount of dietary 22∶6n-3
was degraded via β-oxidation, and that a portion of the retroconverted 20∶5n-3 was recycled for the synthesis of 22∶6n-3. The recycling of
20∶5n-3 might contribute to the low level of 22∶6n-3 in rats fed an n-3-deficient diet. 相似文献
27.
Masako Kashiwagi Shinichi Uehara Ayako Takagi Masahiro Baba 《Journal of the Society for Information Display》2014,22(1):68-75
To widen the vertical and horizontal angular ranges where the lens performs well, the off‐axis performance of a liquid crystal gradient index (LC GRIN) lens is analyzed by the combined simulation system of an LC director simulator and a ray‐tracing simulator. We found that the angular difference between an LC alignment direction and an electrode array direction of the LC GRIN lens is one of significant parameters, and detailed conditions of structure are established. The measurement result shows that the developed structure reduces the degradation ratio in a luminance profile from 61% to 3.2%. We have applied a user tracking system for the rotatable 3D display, equipped with a detection of a panel orientation and a face position. As a result, we have developed a rotatable 2D/3D tablet whose 3D viewing azimuth angle is over 30° in both landscape and portrait orientations. 相似文献
28.
This paper presents an IP finely-distributed load-balanced routing scheme based on two-phase routing over shortest paths, where the traffic matrix is given. It is called the fine two-phase routing (F-TPR) scheme. F-TPR more finely distributes traffic from a source node to intermediate nodes than the original TPR. F-TPR determines the distribution ratios to intermediate nodes for each source–destination node pair independently. To determine an optimum set of distribution ratios, a linear programming (LP) formulation is derived. We compare the F-TPR scheme against the TPR scheme and the sophisticated traffic engineering (TE) scheme of Multi-Protocol Label Switching (MPLS-TE). Numerical results show that F-TPR greatly reduces the network congestion ratio compared to TPR. In addition, F-TPR provides almost the same network congestion ratios as MPLS-TE, the difference is surprisingly less than 0.1% for the various network topologies examined. In addition, considering the practical implementation of F-TPR for routers, we also investigate the case that traffic from a source node to a destination node is not allowed to be split over multiple routes. The non-split problem is formulated as an integer linear programming (ILP) problem. As it is difficult to solve the ILP problem within practical time, two heuristic algorithms are presented: Largest Traffic Demand First (LTDF) and a Random Selection (RS). The applicability of LTDF and RS are presented in terms of network size. We find that non-split F-TPR also matches the routing performance of MPLS-TE within an error of 1%, when network size is large enough. 相似文献
29.
Light-induced yellowing of extruded rigid poly(vinyl chloride) formulations containing 0, 2.5, and 5 phr of titanium dioxide under exposure to monochromatic light was studied. Both photoyellowing and photobleaching were observed as wavelength-dependent phenomena in the range of 280–500 nm. Action spectra for yellowing of the different compounds were similar. In the case of the formulation with no titanium dioxide, significant color changes were observed on the back surface of the sample, indicating transmission of the longer wavelength light through the 1-mm thickness of the sample. 相似文献
30.