磁浮轨道交通产业培育：技术、规划和全产业链的视角

磁浮轨道交通在建设成本等方面具有比较优势,在环保、安全等多方面具备突出特点.中国已经掌握磁浮轨道交通技术,长沙市和北京市已经取得磁浮轨道交通的建设和运营经验,国内发展磁浮轨道交通及其产业的条件已经形成.为了依托磁浮轨道交通培育磁浮产业,从技术、规划和全产业链等方面,需要采取的措施包括:进一步发展磁浮轨道交通技术并对技术实行专利利用和保护,在交通领域规划磁浮轨道交通,培育磁浮轨道交通产业链和产业集群并推动产业的国际化发展,发挥政府对产业的推动作用.湖南省还可以采取建设株洲"中国动力谷"和发展"长沙轨博会"等会展经济及观赏经济的特别措施.     

Reversible near-infrared fluorescence switch by novel photochromic unsymmetrical-phthalocyanine hybrids based on bisthienylethene

A novel family of photochromic hybrids, 2,3-bis(2,5-dimethyl-3-thienyl) unsymmetrical-phthalocyanines (BTE-uPcs), which show a photoregulating fluorescence switch in the near-infrared spectral region were synthesized by a concise route.     

Rare-Earth Chalcohalides: A Family of van der Waals Layered Kitaev Spin Liquid Candidates

The Kitaev spin liquid(KSL) system has attracted tremendous attention in recent years because of its fundamental significance in condensed matter physics and promising applications in fault-tolerant topological quantum computation.Material realization of such a system remains a major challenge in the field due to the unusual configuration of anisotropic spin interactions,though great effort has been made before.Here we reveal that rare-earth chalcohalides REChX(RE=rare earth;Ch=O,S,Se,Te;X=F,Cl,Br,I) can serve as a family of KSL candidates.Most family members have the typical SmSI-type structure with a high symmetry of R■m,and rare-earth magnetic ions form an undistorted honeycomb lattice.The strong spin-orbit coupling of 4f electrons intrinsically offers anisotropic spin interactions as required by the Kitaev model.We have grown the crystals of YbOCl and synthesized the polycrystals of SmSI,ErOF,HoOF and DyOF,and made careful structural characterizations.We carry out magnetic and heat capacity measurements down to 1.8 K and find no obvious magnetic transition in all the samples but DyOF.The van der Waals interlayer coupling highlights the true two-dimensionality of the family which is vital for the exact realization of Abelian/non-Abelian anyons,and the graphene-like feature will be a prominent advantage for developing miniaturized devices.The family is expected to act as an inspiring material platform for the exploration of KSL physics.     

Robust finite-time H∞ control of singular stochastic systems via static output feedback

This paper addresses the problem of robust finite-time stabilization of singular stochastic systems via static output feedback. Firstly, sufficient conditions of singular stochastic finite-time boundedness on static output feedback are obtained for the family of singular stochastic systems with parametric uncertainties and time-varying norm-bounded disturbance. Then the results are extended to singular stochastic H_∞ finite-time boundedness for the class of singular stochastic systems. Designed algorithm for static output feedback controller is provided to guarantee that the underlying closed-loop singular stochastic system is singular stochastic H_∞ finite-time boundedness in terms of strict linear matrix equalities with a fixed parameter. Finally, an illustrative example is presented to show the validity of the developed methodology.     

RESEARCH ANNOUNCEMENTS A Uniform Approximation Model for Instantaneous Frequency Analysis

0 Introduction Signal decomposition is a crucial issue and a key step in signal analysis,which provides the multiscale components for further processing.In many applications related to image and speech/audio processing,it is always necessary to decompose an input signal to extract information such as amplitudes,phases and frequencies.The classical decomposition methods include     

A New Model of Interval-Valued Intuitionistic Fuzzy Weighted Operators and Their Application in Dynamic Fusion Target Threat Assessment

Existing missile defense target threat assessment methods ignore the target timing and battlefield changes, leading to low assessment accuracy. In order to overcome this problem, a dynamic multi-time fusion target threat assessment method is proposed. In this method, a new interval valued intuitionistic fuzzy weighted averaging operator is proposed to effectively aggregate multi-source uncertain information; an interval-valued intuitionistic fuzzy entropy based on a cosine function (IVIFECF) is designed to determine the target attribute weight; an improved interval-valued intuitionistic fuzzy number distance measurement model is constructed to improve the discrimination of assessment results. Specifically, first of all, we define new interval-valued intuitionistic fuzzy operation rules based on algebraic operations. We use these rules to provide a new model of interval-valued intuitionistic fuzzy weighted arithmetic averaging (IVIFWAA) and geometric averaging (IVIFWGA) operators, and prove a number of algebraic properties of these operators. Then, considering the subjective and objective weights of the incoming target, a comprehensive weight model of target attributes based on IVIFECF is proposed, and the Poisson distribution method is used to solve the time series weights to process multi-time situation information. On this basis, the IVIFWAA and IVIFWGA operators are used to aggregate the decision information from multiple times and multiple decision makers. Finally, based on the improved TOPSIS method, the interval-valued intuitionistic fuzzy numbers are ordered, and the weighted multi-time fusion target threat assessment result is obtained. Simulation results of comparison show that the proposed method can effectively improve the reliability and accuracy of target threat assessment in missile defense.     

Chemo/regioselective Aza-Michael additions of amines to conjugate alkenes catalyzed by polystyrene-supported AlCl3

A simple and efficient procedure is presented for Aza-Michael additions of various amines with conjugate alkenes bearing electron withdrawing group catalyzed by polystyrene-supported aluminum chloride (Ps-AlCl₃) without the use of any solvents. The catalyst shows high catalytic activity for both aromatic amines and aliphatic amines. Chemoselective additions of the two types of amines with conjugate alkenes are achieved. Regioselective additions of two different amino groups in one molecule proceed smoothly. Ps-AlCl₃ has better recyclability and can be reused several times without apparent loss of activity.     

Screening and preliminary application of a DNA aptamer for rapid detection of Salmonella O8

We report on a rapid method for the detection of Salmonella O8. It does not require an enrichment step but rather uses an aptamer as a probe that was selected by system evolution of ligands by exponential enrichment (SELEX) assay. Firstly, aptamer against Salmonella O8 was selected from a 78 bp random DNA library that was prepared in-vitro. The binding ability of the aptamers to target bacterium was examined by aptamer-linked immobilized sorbent assay. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. Next, this high affinity aptamer B10 was used to recognize Salmonella O8 via fluorescence microscopy. The selected aptamer has a high specificity and high affinity against its target. We believe that the resulting fluorescence in-situ labeling assay is a potentially useful alternative in rapid screening and detection of foodborne pathogens.