Similarity solutions for the flow behind an exponential shock in a non-ideal gas

Similarity solutions for the flow of a non-ideal gas behind a strong exponential shock driven out by a piston (cylindrical or spherical) moving with time according to an exponential law are obtained. Similarity solutions exist only when the surrounding medium is of constant density. Solutions are obtained, in both the cases, when the flow between the shock and the piston is isothermal or adiabatic. It is found that the assumption of zero temperature gradient brings a profound change in the density distribution as compare to that of the adiabatic case. Effects of the non-idealness of the gas on the flow-field between the shock and the piston are investigated. The variations of density-ratio across the shock and the location of the piston with the parameter of non-idealness of the gas are also obtained.     

A rapid method with ultra‐high‐performance liquid chromatography–tandem mass spectrometry for simultaneous determination of five type B trichothecenes in traditional Chinese medicines

A speedy and selective ultra‐HPLC‐MS/MS method for simultaneous determination of deoxynivalenol (DON), 3‐acetyldeoxynivalenol (3‐ADON), 15‐ADON, nivalenol and fusarenon X in traditional Chinese medicines (TCMs) was developed. The method was based on one‐step sample cleanup using reliable homemade cleanup cartridges. A linear gradient mobile‐phase system, consisting of water containing 0.2% aqueous ammonia and acetonitrile/methanol (90:10, v/v) at a flow rate of 0.4 mL/min, and an Acquity UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm) were employed to obtain the best resolution of the target analytes. [¹³C₁₅]–DON was used as the internal standard to accomplish as accurate as possible quantitation. The established method was further validated by determining the linearity (R²≥0.9990), sensitivity (LOQ, 0.29–0.99 μg/kg), recovery (88.5–119.5%) and precision (RSD≤15.8%). It was shown to be a suitable method for simultaneous determination of DON, 3‐ADON, 15‐ADON, nivalenol and fusarenon X in various TCM matrices. The utility and practical impact of the method was demonstrated using different TCM samples.     

Counter-current chromatographic separation of nucleic acid constituents with a hydrophilic solvent system

Nucleic acid constituents such as nucleobases, nucleosides and nucleotides were separated by counter-current chromatography using type J coil planet centrifuge. The separation was performed with a hydrophilic solvent system composed of 1-propanol/800 mM potassium phosphate buffer (pH 7.4) (1:1, v/v) by eluting the lower aqueous phase at a flow-rate of 0.5 ml/min. Eight selected nucleic acid constituents (4.0 mg, 0.5 mg of each), uridine monophosphate (UMP), adenosine monophosphate (AMP), deoxyadenosine monophosphate (dAMP), uridine, urasile, deoxy uridine, adenosine and adenine were well resolved within 160 min.     

基于最小二乘支持向量机回归的背景偏振光谱二向反射分布建模分析

详细分析了土壤背景偏振光谱二向反射分布函数与探测角及探测方位角之间关系.提出了基于最小二乘支持向量机回归的偏振光谱二向反射分布函数建模,将有限实验观测条件下测量得到的少数偏振光谱二向反射分布函数扩展到2π空间范围内任意入射及观测条件.通过模型结果和实验结果分析比较,表明该模型能很好地满足准确度要求.     

Acoustic detection and classification of river boats

We present a robust algorithm to detect the arrival of a boat of a certain type when other background noises are present. It is done via the analysis of its acoustic signature against an existing database of recorded and processed acoustic signals. We characterize the signals by the distribution of their energies among blocks of wavelet packet coefficients. To derive the acoustic signature of the boat of interest, we use the Best Discriminant Basis method. The decision is made by combining the answers from the Linear Discriminant Analysis (LDA) classifier and from the Classification and Regression Trees (CART) that is also accompanied with an additional unit, called Aisles, that reduces false alarms rate. The proposed algorithm is a generic solution for process control that is based on a learning phase (training) followed by an automatic real time detection while minimizing the false alarms rate.     

On fractional quantum Hall solitons in ABJM-like theory

Using D-brane physics, we study fractional quantum Hall solitons (FQHS) in ABJM-like theory in terms of type IIA dual geometries. In particular, we discuss a class of Chern-Simons (CS) quivers describing FQHS systems at low energy. These CS quivers come from R-R gauge fields interacting with D6-branes wrapped on 4-cycles, which reside within a blown up CP³ projective space. Based on the CS quiver method and mimicking the construction of del Pezzo surfaces in terms of CP², we first give a model which corresponds to a single layer model of FQHS system, then we propose a multi-layer system generalizing the doubled CS field theory, which is used in the study of topological defect in graphene.     

Linearization of vector fields and embedding of diffeomorphisms in flows via Nash–Moser theorem

In the first part of this paper we give suitable spectral properties of the adjoint operators induced by appropriate perturbations of some hyperbolic linear vector fields. These properties are useful to prove general facts based on the Nash–Moser inverse function theorem. In the second part of this work we study circumstances where a global linearization of a vector field X$X$ in a real numerical space is feasible and where some diffeomorphisms which are close to exp(X)$exp\left(X\right)$ can be embedded in a flow.     

Bayesian inference for Pr (Y

《Applied Mathematical Modelling》2014,38(5-6):1698-1709

Exponential stability of uniform Euler–Bernoulli beams with non-collocated boundary controllers

We study the stability of a robot system composed of two Euler–Bernoulli beams with non-collocated controllers. By the detailed spectral analysis, we prove that the asymptotical spectra of the system are distributed in the complex left-half plane and there is a sequence of the generalized eigenfunctions that forms a Riesz basis in the energy space. Since there exist at most finitely many spectral points of the system in the right half-plane, to obtain the exponential stability, we show that one can choose suitable feedback gains such that all eigenvalues of the system are located in the left half-plane. Hence the Riesz basis property ensures that the system is exponentially stable. Finally we give some simulation for spectra of the system.     

Analyticity and exponential stability of semigroups for the elastic systems with structural damping in Banach spaces

In this paper, we consider a second order evolution equation in a Banach space, which can model an elastic system with structural damping. New forms of the corresponding first order evolution equation are introduced, and their well-posed property is proved by means of the operator semigroup theory. We give sufficient conditions for analyticity and exponential stability of the associated semigroups.