守恒双曲方程一类本质非振荡(ENO)格式

用自适应Newton插值,结合自适应模型和重构思想去构造数值流通量,对时间采用Runge-Kutta型离散,得到一类不需"真正"插值和数值微分过程的ENO格式。该格式易于数值实现,数值试验表明,这类格式具有良好的计算结果。     

Confocal depth‐resolved fluorescence micro‐X‐ray absorption spectroscopy for the study of cultural heritage materials: a new mobile endstation at the Beijing Synchrotron Radiation Facility

A confocal fluorescence endstation for depth‐resolved micro‐X‐ray absorption spectroscopy is described. A polycapillary half‐lens defines the incident beam path and a second polycapillary half‐lens at 90° defines the probe sample volume. An automatic alignment program based on an evolutionary algorithm is employed to make the alignment procedure efficient. This depth‐resolved system was examined on a general X‐ray absorption spectroscopy (XAS) beamline at the Beijing Synchrotron Radiation Facility. Sacrificial red glaze (AD 1368–1644) china was studied to show the capability of the instrument. As a mobile endstation to be applied on multiple beamlines, the confocal system can improve the function and flexibility of general XAS beamlines, and extend their capabilities to a wider user community.     

在－50℃~+150℃大温度范围下用FBG测材料的三维热膨胀系数

报导了用光纤布喇格光栅(FBG)传感器测量军工用的一新型材料的新方法.实验结果表明，此方法可在恶劣环境下可靠检测热膨胀系数，FBG在低至－50℃和高至+150℃大范围下仍能正常工作.文中给出了相应理论及实验结果.     

Existence of Boundary Value Problems for Impulsive Fractional Differential Equations with a Parameter

We investigate a class of boundary value problems for nonlinear impulsive fractional dif-ferential equations with a parameter.By the deduction of Altman's theor...     

Resistive switching of in situ and ex situ oxygen plasma treated ZnO thin film deposited by atomic layer deposition

In situ and ex situ oxygen plasma treatment (OPT) were applied to treat ZnO thin films deposited by thermal atomic layer deposition (T-ALD), and the resistive switching (RS) behaviors of the films were investigated. For the in situ OPT, the treatment was applied after each T-ALD cycle. For the ex situ OPT, the treatment was applied on the as-grown film. The T-ALD-grown ZnO films were defect-rich and conductive with no RS behavior. After the OPT process, the resistivity of the films increased drastically, which is believed to be mainly due to the removal of hydrogen impurities, and the films showed bipolar RS characteristics. The dominant conduction mechanisms are the trap-controlled space charge limited current and ohmic behavior at different field regions. The RS behavior was induced upon the formation/disruption of the conducting filaments. Owing to the homogeneous chemical composition and fewer defects, the resistance ratio of the in situ OPT ZnO film is higher than that of the ex situ OPT film, implying that the in situ OPT method is an efficient way to fabricate resistive random access memory devices using the ALD-grown ZnO films.     

SIMULATION OF THE IN-PILE BEHAVIORS EVOLUTION IN NUCLEAR FUEL RODS WITH THE IRRADIATION DAMAGE EFFECTS

Based on the commercial computational software, a three-dimensional finite ele- ment model to simulate the thermo-mechanical behaviors in a nuclear fuel rod is established; By taking into consideration irradiation-swelling of the pellet and the irradiation damage effects in the cladding together with the coupling effects between the temperature field and the mechanical field, the user subroutines to define the special material performance and boundary conditions have been developed independently and validated. Three-dimensional numerical simulation of the thermo-mechanical coupling behaviors in a nuclear fuel rod is carried out, and the evolution rules of the important thermal and mechanical variables are obtained and analyzed. The research re- sults indicate that： （i） the fuel pellets will be in contact with the cladding at high burnup, which will induce a strong mechanical interaction between them; （2） the irradiation creep effect plays an important role in the mechanical behavior evolution in the nuclear fuel rod.     

利用弹簧支承巧解超静定刚架

对于某些超静定刚架的内力,用力法或位移法计算,由于未知量很多,计算相当麻烦. 如果采用弹簧支承对刚架结构进行简化,然后再用力法计算,可使基本未知量数大为减少. 使计算变得简便易行.     

Czerny-Turner imaging spectrometer for broadband spectral simultaneity

A modified asymmetrical Czerny-Turner arrangement with a fixed plane grating is proposed to correct aberrations over a broadband spectral range by analyzing the dependence of aberrations for different wavelengths. The principle of design is deduced in detail. We compare the performance of this modified Czerny-Turner imaging spectrometer with that of the existing Czerny-Turner arrangement by using a practical Czerny-Turner imaging spectrometer example. The excellent performance of the modified imaging spectrometer is confirmed by simulation with ZEMAX software.