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101.
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103.
Michihito Ueda Masahiro Ueda Hiroaki Takagi Masayuki J. Sato Toshio Yanagida Ichiro Yamashita Kentaro Setsune 《Physica A》2008,387(16-17):4475-4481
“End of Moore’s Law” has recently become a topic. Keeping the signal-to-noise ratio (SNR) at the same level in the future will surely increase the energy density of smaller-sized transistors. Lowering the operating voltage will prevent this, but the SNR would inevitably degrade. Meanwhile, biological systems such as cells and brains possess robustness against noise in their information processing in spite of the strong influence of stochastic thermal noise. Inspired by the information processing of organisms, we propose a stochastic computing model to acquire information from noisy signals. Our model is based on vector matching, in which the similarities between the input vector carrying external noisy signals and the reference vectors prepared in advance as memorized templates are evaluated in a stochastic manner. This model exhibited robustness against the noise strength and its performance was improved by addition of noise with an appropriate strength, which is similar to a phenomenon observed in stochastic resonance. Because the stochastic vector matching we propose here has robustness against noise, it is a candidate for noisy information processing that is driven by stochastically-operating devices with low energy consumption in future. Moreover, the stochastic vector matching may be applied to memory-based information processing like that of the brain. 相似文献
104.
A simplified and accurate assay of cholesterol 7 alpha-hydroxylase activity using 5 alpha-cholestane-3 beta,7 beta-diol as an internal standard is described. Endogenous microsomal cholesterol was used as the substrate. Following incubation and addition of the internal standard, lipids extracted from the incubation mixture were applied to Bond-Elut silica cartridge columns. 7 alpha-Hydroxycholesterol, 7 beta-hydroxycholesterol, 7-ketocholesterol and the internal standard were quantitatively recovered by eluting the column with 6 ml of benzene-ethyl acetate (2:3, v/v) after removal of cholesterol with 6 ml of benzene-ethyl acetate (9:1, v/v). After trimethylsilylation, the mass of 7 alpha-hydroxycholesterol was determined by capillary gas chromatography with selected-ion monitoring. The method permits a faster, easier and more sensitive determination of the activity of cholesterol 7 alpha-hydroxylase in small samples. 相似文献
105.
Shinji Takesue 《Journal of statistical physics》1989,56(3-4):371-402
This is the first part of a series devoted to the study of thermodynamic behavior of large dynamical systems with the use of a family of fully-discrete and conservative models named elementary reversible cellular automata (ERCAs). In this paper, basic properties such as conservation laws and phase space structure are investigated in preparation for the later studies. ERCAs are a family of one-dimensional reversible cellular automata having two Boolean variables on each site. Reflection and Boolean conjugation symmetries divide them into 88 equivalence classes. For each rule, additive conserved quantities written in a certain form are regarded as a kind of energy, if they exist. By the aid of the discreteness of the variables, every ERCA satisfies the Liouville theorem or the preservation of phase space volume. Thus, if an energy exists in the above sense, statistical mechanics of the model can formally be constructed. If a locally defined quantity is conserved, however, it prevents the realization of statistical mechanics. The existence of such a quantity is examined for each class and a number of rules which have at least one energy but no local conservation laws are selected as hopeful candidates for the realization of thermodynamic behavior. In addition, the phase space structure of ERCAs is analyzed by enumerating cycles exactly in the phase space for systems of comparatively small sizes. As a result, it is revealed that a finite ERCA is not ergodic, that is, a large number of orbits coexist on an energy surface. It is argued that this fact does not necessarily mean the failure of thermodynamic behavior on the basis of an analogy with the ergodic nature of infinite systems. 相似文献
106.
The effect of oxygen isotope substitution on the transition temperature Tc of a superconducting (Nd1−xCex)2CuO4−δ system was studied, where the special synthetic method was taken to minimize ambiguous factors on the oxygen concentration and to guarantee the complete substitution of 16O by 18O. The isotope exponent in the relationship of Tc∝1/M was estimated to be less than 0.15 by magnetic susceptibility measurements. 相似文献
107.
Vallum Krishna Reddy Jun‐Ichi Onogawa Lakonda Nagaprasada Rao Tatsuo Oshikawa Masaki Takahashi Mitsuji Yamashita 《Journal of heterocyclic chemistry》2002,39(1):69-75
The synthesis of the novel 1‐(substituted phenoxy/phenyl)‐2‐phospholene and phospholane 1‐oxide derivatives, which are analogs of sugars having a phosphorus atom in place of the ring oxygen of normal sugars, is described. All of the synthesized derivatives are structurally characterized by multi nuclear NMR, mass, and IR spectral data, elemental and X‐ray crystallographic analyses. 相似文献
108.
A spinel-type structure was found in cadmium stannate CdSnO3 prepared by thermal decomposition of the hydroxostannate CdSn(OH)6 at 550–800°C. Its occurrence depends strongly on the precipitation conditions of CdSn(OH)6 from CdCl2 and Na2Sn(OH)6 aqueous solutions. In the (Cd1–xCax)SnO3 system, the spinel phase appears in the composition range of 0.0 ≤ x ≤ 0.35. The experimental results suggest the presence of cation vacancies in the spinel octahedral sites. 相似文献
109.
Apparent molal heat capacities as a function of the degree of neutralization have been determined for dilute aqueous solutions of poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA), copoly(maleic acid-ethylene) (MAEt), and copoly(maleic acid-styrene) (MASt) using direct flow microcalorimetry. Apparent molal volumes were measured as well. Both molal heat capacity and molal volume decrease with increasing ionization of the polymer. The effect of the hydrophobic interactions of the methyl group or phenyl group was obtained from the difference in the molal quantities of PMA and PAA, or MASt and MAEt. No evidence of hydrophobic effects, as determined from the heat capacity, was found for the conformational transition of PMA, but the hydration of the phenyl groups in MASt was found to be changed significantly at a degree of neutralization of 0.4. 相似文献