13 resultados para Exposición Universal, París 1900
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
给出相对论力学中普遍定律的实用判别法和协变集的实用构造法,还给出实现非普遍定律的“可导出性”的一种实用方法.
Resumo:
An attempt is made to determine the form of F(x), the dimensionless function of universal nature which occurs in the energy spectrum for the universal equilibrium range of fully developed turbulence, by the method of statistical mechanics without introducing any parameter of semiempirical nature. Then, the validity of the variational approach to the closure problem of turbulence theory is tested by applying it to the study of the universal equilbrium range of turbulence.
Resumo:
A universal Biot number of ceramics, which not only determines the susceptibility of the ceramics to quenching but also indicates the duration that the ceramics fail during thermal shock, is theoretically obtained. The present analysis shows that the thermal shock failure of the ceramics with a Biot number greater than this universal value is a very rapid process that just occurs in the initial regime of the heat conduction of the ceramics. This universal Biot number provides a guide to the selection of the ceramics applying to the thermostructural engineering including thermal shock.
Resumo:
We propose a universal quantum computation scheme for trapped ions in thermal motion via the technique of adiabatic passage, which incorporates the advantages of both the adiabatic passage and the model of trapped ions in thermal motion. Our scheme is immune from the decoherence due to spontaneous emission from excited states as the system in our scheme evolves along a dark state. In our scheme the vibrational degrees of freedom are not required to be cooled to their ground states because they are only virtually excited. It is shown that the fidelity of the resultant gate operation is still high even when the magnitude of the effective Rabi frequency moderately deviates from the desired value.
Resumo:
We present a universal analyzer for the three-particle Greenberger-Horne-Zeilinger (GHZ) states with quantum nondemolition parity detectors and linear-optics elements. In our scheme, all of the three-photon GHZ states can be discriminated with nearly unity probability in the regime of weak nonlinearity feasible at the present state of the art experimentally. We also show that our scheme can be easily extended to the analysis of the multi-particle GHZ states.
Resumo:
This paper proposes smart universal multiple-valued (MV) logic gates by transferring single electrons (SEs). The logic gates are based on MOSFET based SE turnstiles that can accurately transfer SEs with high speed at high temperature. The number of electrons transferred per cycle by the SE turnstile is a quantized function of its gate voltage, and this characteristic is fully exploited to compactly finish MV logic operations. First, we build arbitrary MV literal gates by using pairs of SE turnstiles. Then, we propose universal MV logic-to-value conversion gates and MV analog-digital conversion circuits. We propose a SPICE model to describe the behavior of the MOSFET based SE turnstile. We simulate the performances of the proposed gates. The MV logic gates have small number of transistors and low power dissipations.
Resumo:
This paper proposes novel universal logic gates using the current quantization characteristics of nanodevices. In nanodevices like the electron waveguide (EW) and single-electron (SE) turnstile, the channel current is a staircase quantized function of its control voltage. We use this unique characteristic to compactly realize Boolean functions. First we present the concept of the periodic-threshold threshold logic gate (PTTG), and we build a compact PTTG using EW and SE turnstiles. We show that an arbitrary three-input Boolean function can be realized with a single PTTG, and an arbitrary four-input Boolean function can be realized by using two PTTGs. We then use one PTTG to build a universal programmable two-input logic gate which can be used to realize all two-input Boolean functions. We also build a programmable three-input logic gate by using one PTTG. Compared with linear threshold logic gates, with the PTTG one can build digital circuits more compactly. The proposed PTTGs are promising for future smart nanoscale digital system use.
Resumo:
A universal Biot number, which not only describes the susceptibility of ceramic cylinders to quenching but also determines the duration that ceramic cylinders are subjected to thermal stress during thermal shock, is theoretically obtained. The analysis proves that thermal shock failure of ceramic cylinders with a Biot number greater than the critical value is a rapid process, which only occurs in the initial heat conduction regime. The results provide a guide to the selection of ceramic materials for thermostructural engineering, with particular reference to thermal shock.
Resumo:
An enzyme responsive nanoparticle system that uses a DNA-gold nanoparticle (AuNP) assembly as the substrate has been developed for the simple, sensitive, and universal monitoring of restriction endonucleases in real time. This new assay takes advantage of the palindromic recognition sequence of the restriction nucleases and the unique optical properties of AuNPs and is simpler than the procedure previously described by by Xu et al. (Angew. Chem. Int. Ed. Engl. 2007, 46, 3468-3470). Because it involves only one type of ssDNA modified AuNPs, this assay can be directed toward most of the endonucleases by simply changing the recognition sequence found within the linker DNA. In addition, the endonuclease activity could be quantitatively analyzed by the value of the reciprocal of hydrolysis half time (t(1/2)(-1). Furthermore, our new design could also be applied to the assay of methyltransferase activity since the methylation of DNA inhibits its cleavage by the corresponding restriction endonuclease, and thus, this new methodology can be easily adapted to high-throughput screening of methyltransferase inhibitors.