Simultaneous temperature and refractive index measurement of liquid using a local micro-structured fiber Bragg grating

An alternative solution for the simultaneous measurement of temperature and refractive index is presented. A local micro-structured fiber Bragg grating（LMSFBG）is formed as the sensing head,in which a standard grating is etched by HF.According to the phase shift theory,the main spectral change of the LMSFBG is the formation of a narrow allowed band,which is strongly dependent on the etching features and the surrounding refractive index.As such,the temperature and refractive index measurements can be achieved by the shifts of the double peaks and narrow allowed band,and their fitting linearity coefficients are 0.996 and 0.994,respectively.Thus,the reflection and transmission peaks of the LMSFBG have a good linear relationship with temperature and refractive index.     

模压全息衍射效率的分析

本文指出光刻胶所记录到的是浮雕型相位光栅,经历了电铸、模压转移到PET薄膜上,在此过程中光栅刻蚀深度的转移是非线性的,即深度浅的地方,其最后结果将更浅,甚至丢失。由于散射物体散斑的光强分布是严重不均匀的,故光刻胶上记录下各散斑的光栅刻蚀深度也严重不均匀,经过电铸、模压后,进一步加重了这种不均匀性,使得模压片的衍射效率降低,解决的办法是尽可能地使各个散斑上的光栅刻蚀深度趋于均匀化。     

Robust reliable stabilization of uncertain switched neutral systems with delayed switching

This paper investigates the problem of robust reliable control for a class of uncertain switched neutral systems under asynchronous switching, where the switching instants of the controller experience delays with respect to those of the system and the parameter uncertainties are assumed to be norm-bounded. A state feedback controller is proposed to guarantee exponential stability and reliability for switched neutral systems, and the dwell time approach is utilized for the stability analysis and controller design. A numerical example is given to illustrate the effectiveness of the proposed method.     

Simultaneous species and sex identification of silkworm pupae using hyperspectral imaging technology

To obtain high-quality raw silk and improve the economic values of sericulture industry, sex needs to be discriminated first before cross-breeding. Much work has been reported about sex identification. However, to realize automatic separation of silkworm pupae, the species also needs to be classified, which no research has ever explored. Hence, this paper studied the feasibility of visible and near-infrared hyperspectral imaging technology to identify the species and sex of silkworm pupae. 288 hyperspectral images of silkworm pupae were collected and the average spectra were extracted from the region of interest, around the tail region of silkworm pupae. Successive projection algorithm was served as a variable selection method to choose the optimal wavelengths from the full spectra. At the same time, principal component analysis was used to choose the characteristic images. Then, the gray-level co-occurrence matrix was implemented on the first three principal component images (accounted for 99.05% of the total variances) to extract 48 textural features. Partial least squares discriminant analysis and support vector machine models were built, respectively, based on the spectral data, textural data and fusion data that included spectral and textural data, in which the support vector machine model based on the fusion data, gave the best species and sex identification result with an accuracy of 95.83%. It demonstrated that the hyperspectral imaging technology could be a new and nondestructive method to replace the manual work.     

UHPLC–MS/MS analysis of sphingosine 1‐phosphate in joint cavity dialysate and hemodialysis solution of adjuvant arthritis rats: Application to geniposide pharmacodynamic study

Geniposide (GE) is an iridoid glycoside compound with anti‐inflammatory effect. The potential of sphingosine 1‐phosphate (S1P) as a plasma marker in human diseases was suggested recently in the literature, which demonstrated that, in patients with inflammatory diseases, plasma S1P was elevated. It follows that the obstructive coronary artery disease can be predicted with serum S1P. Therefore, S1P can also be potentially used as a pharmacodynamic marker to study adjuvant arthritis (AA) rats. In the current study, a UHPLC–MS/MS method combined with the microdialysis sampling technique (using FTY720 phosphate as an internal standard) was adopted and validated to measure S1P levels in the hemodialysis fluid and joint cavity dialysates of AA rats after oral administration of GE. A S1P concentration–time curve in the dialysate was established in this study. It was demonstrated that GE exerted an anti‐inflammatory effect by reducing AA‐induced elevated S1P levels. It is showed that changes in S1P concentrations over time can be used to monitor the pharmacodynamic effects of GE in treating AA rats in pharmacodynamic studies.     

Stochastic Traveling Wave Solution to a Stochastic KPP Equation

In this paper, we consider the stochastic KPP equation which is perturbed by an environmental noise. Applying an extended stochastic ordering technique, we establish the existence of a stochastic traveling wave solution to the equation and give a sufficient condition under which solutions can be attracted to the stochastic traveling wave.     

一种长周期光纤光栅边沿滤波线性解调新方法

光纤光栅作为一种新型的传感器件,有着巨大的应用价值。利用长周期光纤光栅的滤波特性,提出了一种可应用于光纤光栅传感解调的新方法。即利用长周期光纤光栅作为边沿滤波器的基本器件,可完成一路或者多路光纤光栅的传感波长解调。该解调方案基于光强度测量,适用于动态和静态测量。而且由于采用全光结构设计,无须机械部件调谐,因此,可大大提高解调速度。具有系统反映迅速,性能价格比高等优点。经实验,实现了在5nm范围内的波长线性解调。测量波长分辨极限为0．002nm,解调速度数十kHz。     

On the Boussinesq–Burgers equations driven by dynamic boundary conditions

We study the qualitative behavior of the Boussinesq–Burgers equations on a finite interval subject to the Dirichlet type dynamic boundary conditions. Assuming $H^1\times H^2$ initial data which are compatible with boundary conditions and utilizing energy methods, we show that under appropriate conditions on the dynamic boundary data, there exist unique global-in-time solutions to the initial-boundary value problem, and the solutions converge to the boundary data as time goes to infinity, regardless of the magnitude of the initial data.     

数值流形方法研究及应用进展

基于有限覆盖技术的数值流形方法是一种新的广义的数值方法.该方法的场函数近似原理和有限元、无网格、单位分解等方法相似,但在网格划分、覆盖形式、近似函数等方面有其自身的特点和优势.对该方法近年来在理论研究和应用方面取得的重要进展进行了综述.在理论研究方面, 目前已对不同形式物理覆盖流形单元的性能进行了研究,结果表明流形单元的精度较有限单元高,且提高覆盖函数的阶次能提高单元的精度;同时理论研究已由二维低阶流形方法推广到三维高阶流形方法,由线性流形方法推广到非线性流形方法,由基于能量原理的流形方法推广到基于加权余量的流形方法,非协调流形方法、无网格流形方法等也已开展了研究; 此外,覆盖系统的自动生成、覆盖函数的形式以及边界条件的处理方法等流形方法相关理论的研究也取得了进展.在应用方面,开展了有关岩石破坏和裂纹扩展等非连续变形分析更深入的研究,并已逐步推广到金属塑性变形分析、多孔介质变形分析以及温度场的数值分析等多个领域.针对目前流形方法的研究和应用现状,该文展望了流形方法理论及实现方法的研究方向、及其在计算流体力学、金属成形等大变形问题、多物理场分析等领域的应用前景.      

Photodissociation dynamics of allyl bromide at 234, 265, and 267 nm

The photodissociation dynamics of allyl bromide was investigated at 234, 265, and 267 nm. A two-dimensional photofragment ion velocity imaging technique coupled with a [2+1] resonance-enhanced multiphoton ionization scheme was utilized to obtain the angular and translational energy distributions of the nascent Br* (2P1/2) and Br (2P3/2) atoms. The Br fragments show a bimodal translational energy distribution, while the Br* fragments reveal one translational energy distribution. The vertical excited energies and the mixed electronic character of excited states were calculated at ab initio configuration interaction method. It is presumed that the high kinetic energy bromine atoms are attributed to the predissociation from 1(pipi*) or 1(pisigma*) state to the repulsive 1(nsigma*) state, and to the direct dissociation from 3(nsigma*) and 3(pisigma*) states, while the low kinetic energy bromine atoms stem from internal conversion from the lowest 3(pipi*) state to 3(pisigma*) state.