非参数自回归模型异方差的小波检验

本文讨论了非参数自回归模型异方差的检验问题.在非参数自回归模型的建模过程中,通常假定方差为常数.然而在建模前,我们应该首先检验这-假定是否成立.本文将利用小波方法来检验异方差问题.我们首先利用核估计方法定义经验小波系数,然后讨论其渐近性质.在此基础上,我们提出了异方差性检验的统计量.数值模拟结果表明,我们的方法表现良好.     

Thermoelectric power generation in a thermoacoustic refrigerator

Commercially available solid-state thermoelectric devices may be used for their electrical power generation capabilities when coupled to a thermoacoustic refrigerator or heat pump. General performance characteristics as well as bulk thermal conductivity for a selection of thermoelectric elements was first found by using a two-plate apparatus to maintain a constant temperature difference across the element. Further studies of an element’s performance when placed in series with the thermoacoustic refrigerator’s heat exchangers will be presented. Design considerations for using thermoelectric elements in a no-moving parts electrical power generation scheme will be discussed.     

Acoustic power measurements of a damped aeroacoustically driven resonator

Strong self-sustained acoustic oscillations may occur in a gas pipe network under certain gas flow velocities within the network. The pipe network under consideration consists of a main pipe, with a variable mean airflow, with two closed coaxial side branches of variable but equal length joined to the main pipe. Coupling between resonant acoustic standing waves and instabilities of the shear layers separating the flow in the main pipe from the stagnant gas in the closed side branches leads to strong acoustic oscillations at a frequency corresponding to the half-wavelength acoustic mode defined by the total side-branch length. An acoustic damper consisting of a variable acoustic resistance and compliance is used to dissipate power from the resonating mode. The response of the aeroacoustically driven resonator to variable damping will be examined for different fluid flow regimes as well as side-branch geometries.     

Extremely low vertical-emittance beam in the accelerator test facility at KEK

Electron beams with the lowest, normalized transverse emittance recorded so far were produced and confirmed in single-bunch-mode operation of the Accelerator Test Facility at KEK. We established a tuning method of the damping ring which achieves a small vertical dispersion and small x-y orbit coupling. The vertical emittance was less than 1% of the horizontal emittance. At the zero-intensity limit, the vertical normalized emittance was less than 2.8 x 10(-8) rad m at beam energy 1.3 GeV. At high intensity, strong effects of intrabeam scattering were observed, which had been expected in view of the extremely high particle density due to the small transverse emittance.     

集值序上鞅的若干有关问题

本文研究了连续时间的集值序上鞅,在一定的假设下我们证明了集值序上鞅有ｈ－Ｒｉｅｓｚ分解,然后证明了集值序上鞅的Ｄｏｏｂ－Ｍｅｙｅｒ分解定理。     

Theory of inert gas-condensing vapor thermoacoustics: propagation equation

The theory of acoustic propagation in an inert gas-condensing vapor mixture contained in a cylindrical pore with wet walls and an imposed temperature gradient is developed. It is shown that the vapor diffusion effects in the mixture are analogous to the heat diffusion effects in the thermoacoustics of inert gases, and that these effects occur in parallel with the heat diffusion effects in the wet system. The vapor diffusion effects can be expressed in terms of the thermoviscous function F(lambda) used in the theory of sound propagation of constant cross-section tubes. As such, these results can be extended to any shape parallel-walled tube. The propagation equations predict that the temperature gradient required for onset of sound amplification in a wet-walled prime mover is much lower than the corresponding temperature gradient for an inert gas prime mover. The results of a measurement of the onset temperature of a simple demonstration prime mover in air with a dry stack and with a stack wetted with water provide a qualitative verification of the theory.     

Characteristics of the sampling paddle modules of neutron wall from the cosmic ray test

In the construction of a large area neutron detector(neutron wall)that is used to detect neutrons at GeV energies,the performances of all the sampling paddle modules prepared for the neutron wall areinvestigated with a specially designed test bench.Tested by cosmic rays,an average intrinsic time resolution of 222.5 ps is achieved at the center of the modules.The light attenuation length and the effective speed of the light in the module are also investigated.     

Study of BESⅢ MUC offline software with cosmic-ray data

Cosmic-ray data of 90 M events have been collected and used for calibration, alignment as well as detector tuning. A special tracking algorithm for the BESⅢ muon counter is developed and verified with Monte-Carlo simulation and then further confirmed with the cosmic-ray data. The obtained strip resolutions are in good agreement with the design values. A new alignment approach for the BESⅢ muon counter is confirmed with the cosmic-ray data and proposed to be used in future analysis of experimental data.     

Direct Observation of NN Pairs Transfer in GaP1-xNx （x=0.12%）

Time-resolved photoluminescence （TRPL） was applied to investigate the transient process in GaP1-xNx （x = 0.12%） alloy. The filling, transferring and decay processes among nitrogen pairs are directly observed. The NN4 pair, either not present or only a small obscure peak under a proper excitation condition in the steady-state photoluminescence spectrum, is well resolved by TRPL.