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71.
An integrated optical-disk pickup that uses a focusing grating coupler with a numerical aperture of 0.45 (a focal length of 1.0 mm and an aperture of 1.0 mm × 0.8 mm) was developed, and the readout signal on an International Standards Organization (ISO) -formatted 90-mm optical disk was detected by the pickup. The signal-amplitude ratio of the minimum-limit data pattern to the maximum was 0.53 on the innermost track. It meets the requirement on the signal resolution for optical-disk storage devices. 相似文献
72.
Hirokazu Yoshizawa Gabor C. Temes 《IEEE transactions on circuits and systems. I, Regular papers》2007,54(1):193-199
This paper describes high-precision switched-capacitor (SC) track-and-hold amplifier (THA) stages. They use a novel continuous-time correlated double sampling (CDS) scheme to desensitize the operation to amplifier imperfections. Unlike earlier predictive-CDS amplifiers, the circuits do not need a sampled-and-held input signal for their operation. During the tracking period, an auxiliary continuous-time signal path is established, which predicts the output voltage during the holding period. This allows accurate operation even for low amplifier gains and large offsets over a wide input frequency range. Extensive simulations were performed to compare the performance of the proposed THAs with earlier circuits utilizing CDS. The results verify that their operation is far more robust than that of any previously described SC amplifiers 相似文献
73.
Kumaki S. Takata H. Ajioka Y. Ooishi T. Ishihara K. Hanami A. Tsuji T. Watanabe T. Morishima C. Yoshizawa T. Sato H. Hattori S. Koshio A. Tsukamoto K. Matsumura T. 《Solid-State Circuits, IEEE Journal of》2002,37(3):450-454
A scalable single-chip 422P@ML MPEG-2 video, audio, and system encoder LSI for portable 422P@HL system is described. The encoder LSI is implemented using 0.13-μm embedded DRAM technology. It integrates 3-M logic gates and 64-Mb DRAM in an area of 99-mm2. The power consumption is suppressed to 0.7 W by adopting a low-power DRAM core. It performs real-time 422P@ML video encoding, audio encoding, and system encoding with no external DRAM. Furthermore, the encoder LSI realizes a 422P@HL video encoder with multichip configuration, due to its scalable architecture. This results in a PC-card size 422P@HL encoder for portable HDTV codec system 相似文献
74.
Cox's proportional hazards regression model is a useful statistical tool for the analysis of 'survival data' from longitudinal studies. This multivariate method compares the 'survival experience' between two or more exposure groups while allowing for simultaneous adjustment of confounding due to one or more covariates. In addition to the summary regression statistics, further insight on the exposure--response relationship can be gained by visually examining the covariates-adjusted survival curves in the respective comparison groups. Covariates-adjusted survival curves are usually computed by the 'average covariate method'. This method is, however, subject to potential drawbacks. A method that avoids these drawbacks is to estimate adjusted survival curves by the corrected group prognostic curves approach. We have written a computer program to construct survival curves by the latter method. The program is coded in the Interactive Matrix Language of SAS. 相似文献
75.
76.
Nitta S. Yoshizawa M. Yambe T. Tanaka M. Takeda H. 《IEEE transactions on bio-medical engineering》1995,42(12):1165-1173
The maximum elastance of the ventricle (Emax) is a strong candidate for a quantitative index used for determination of the timing of weaning the patient from a left ventricular assist device (LVAD). The authors present a new and less invasive method for deriving Emax of the left ventricle under the LVAD assistance. In this method (the CoP method), Emax can be calculated from two different end-systolic points which are produced by changing the drive phase of LVAD without any vascular clamping and any direct measurement of the left ventricular volume. Animal experiments indicated that the CoP method is useful when the measured left ventricular flow and pressure are employed. Moreover, a new technique for estimating the left ventricular flow was developed to make the CoP method less invasive without direct measurement of the flow. The technique could considerably improve the estimation accuracy of the flow in the co-pulsation mode in comparison with the previous one proposed by the authors. However, it has been revealed that the estimation accuracy of the left ventricular flow was not globally high enough to apply the CoP method to clinical cases in spite of its much less invasiveness 相似文献
77.
A 0.9-V 0.5-μA, rail-to-rail CMOS operational amplifier designed with weak inversion techniques is presented. Depletion-mode nMOS transistors buffer a bulk-driven pMOS differential pair to realize wide input dynamic range, while the output stage architecture provides symmetric rail-to-rail output drive through the use of a low-voltage translinear control circuit 相似文献
78.
Yoshizawa M. Takeda H. Yambe T. Nitta S. 《IEEE engineering in medicine and biology magazine》1994,13(5):687-692
The authors' group has recently developed an expert system realized by means of fuzzy logic algorithms for monitoring and malfunction diagnosis of the left ventricular assist device (LVAD), one of the many types of artificial hearts developed today. The system is named TOTOMES (Tohoku University and Toyohashi University of Technology, monitoring and estimation system). TOTOMES is suitable for clinical application because it operates in an online and realtime fashion on a widely used personal computer in Japan. This article introduces the structure and function of the TOTOMES and explains its techniques, such as multi-interrupt tasks and dynamic system identification; as well as fuzzy reasoning used for realizing state estimation, detection, and diagnosis of malfunctions; and monitoring for cardiovascular dynamics under ventricular assistance and the LVAD drive system 相似文献
79.
The widths at half-value of high-resolution NMR spectra of bound water of cellulose were studied in relation to the temperature change. Two points were made clear: First, the amount of bound water of the cellulose sample can be pointed out with higher accuracy the lower the temperature of the measurement. Second, it is possible to determine in a simple manner the boundary temperature Tc at which water molecules become bound by the cellulose. Tc is characteristic of the cellulose sample of a given water content and corresponds to the glass transition temperature of the water-containing sample. The measurements appear to be readily applicable to other hydrophilic polymers. 相似文献
80.
Paromomycin binding induces a local conformational change in the A-site of 16 S rRNA 总被引:1,自引:0,他引:1
Site-directed mutagenesis studies have shown that the isopenicillin N synthase of Cephalosporium acremonium (cIPNS) requires two essential histidine residues (H216, H272) for activity. The determination of iron bound to the wildtype cIPNS and its absence in the mutants lacking histidine at positions 216 and 272 clearly supports the essential role these two histidines play in iron binding. However, nuclear magnetic resonance (NMR) studies have indicated that there could be three histidine residues that possibly coordinate the essential iron at the active site. To search for a presumed third histidine ligand, mutant cIPNS genes containing mutations at two histidine codons were created by in vitro cloning of fragments from the expression vectors bearing the respective cIPNS genes each with a single histidine mutation at positions H49, H64, H116, H126 and H137. All ten possible double histidine mutant cIPNS constructs were subsequently expressed in Escherichia coli. If a third histidine had a participatory role in the iron active centre of cIPNS, then one of the constructed double histidine mutants would have lost its enzymatic activity. However, analysis of the cIPNS activities of these recombinant double histidine mutants indicated that none of them was totally inactivated. Thus, the involvement of a third histidine can be repudiated. 相似文献