Optimal Sensor Placement Method Considering the Importance of Structural Performance Degradation for the Allowable Loadings for Damage Identification

Considering the importance of damage for the structural performance and for decreasing the identification error, this paper proposes an optimal sensor placement method based on a weighted standard deviation norm (WSDN) index. The standard deviation of the identified damage parameters is solved using the series expansion theory and probabilistic method to quantify the effect of a measurement error on damage identification. The damage estimation weight (DEW) index, which can reflect the importance of each element in the structural capabilities, is established based on a performance-damage curve. A significant DEW for a specified element indicates that the element is important for the structure and that its identification error should be small. The WSDN index is obtained from the Hadamard product of the standard deviations (SDs) and DEWs. Thus, the identification error of the entire structure is measured using the weighting coefficient. The optimal sensor placement (OSP) procedure is performed by minimizing the WSDN index. The proposed method can clearly decrease the uncertainties of the identification results for the important elements. Other OSP criteria, including the condition number, information entropy, and standard deviation norm, which aim to decrease the identification error, are discussed in this paper for comparison with the proposed method. Two numerical examples and an experiment, which pertain to the deformation performance, buckling features, and dynamic characteristics, are discussed to verify the advantages of the proposed method.     

Halin-图的点强全染色

图G(V,E)的一个k-正常全染色f叫做一个k-点强全染色当且仅当对任意v∈V(G), N[v]中的元素被染不同色,其中N[v]={u|uv∈V(G)}∪{v}．χTvs(G)=min{k|存在图G的k- 点强全染色}叫做图G的点强全色数．对3-连通平面图G(V,E),如果删去面fo边界上的所有点后的图为一个树图,则G(V,E)叫做一个Halin-图．本文确定了最大度不小于6的Halin- 图和一些特殊图的的点强全色数XTvs(G),并提出了如下猜想:设G(V,E)为每一连通分支的阶不小于6的图,则χTvs(G)≤△(G) 2,其中△(G)为图G(V,E)的最大度．     

Molecular dynamics simulation of P-V-T relationship of ZnO with rock-salt structure using pair-wise interactions

Molecular dynamics (MD) method is used to investigate the behavior of the pressure-volume-temperature (P-V-T) relationship, lattice constant and thermal expansivity for ZnO with rock-salt structure at high pressures and temperatures. The interionic potential is taken to be the sum of pair-wise additive Coulomb, van der Waals attraction, and repulsive interactions. The isothermal and isobaric properties are discussed from the corresponding P-V-T relationship, and it is shown that the MD simulation is successful in reproducing the measured volumes of ZnO over a wide range of temperature and pressure. Meanwhile, the equations of state parameters including lattice constant, linear thermal expansion coefficient, and isothermal bulk modulus are calculated and compared with the available experimental data and the latest theoretical results. At an extended pressure and temperature range, P-V-T relationship, lattice constant, and linear thermal expansion coefficient have been predicted. The structural and thermodynamic properties of ZnO with rock-salt structure are summarized in the pressure 0-100 GPa ranges and the temperature up to 3100 K.     

基于咪唑羧酸配体镉(Ⅱ)配合物的合成、结构调控及其性质表征

利用水热法，以2-（4-羧基-苯基）咪唑-4，5-二羧酸（H₃L）为主配体，在辅配体1，10-菲咯啉（1，10-phen）和1，4-二（1-咪唑基）苯（dib）的调控作用下得到2个新的镉（Ⅱ）配合物：[Cd₂（HL）₂（1，10-phen）₂（H₂O）₂]（1），{[Cd （HL）（dib）_0.5（H₂O）₂]·2H₂O}_n（2）。并通过单晶X射线衍射、元素分析、热重分析、粉末X射线衍射、红外光谱、Hirshfeld表面分析和密度泛函理论量化计算对1和2进行了分析和表征。配合物1和2均属于三斜晶系和P1空间群，且1为零维结构，2为一维链状结构。     

开链冠醚Schiff碱-稀土配合物的合成、表征及近红外发光光谱研究

合成了3个新型开链冠醚Schiff碱-稀土离子三元配合物RE(H2L)(Mq)(NO3)3,其中RE=Nd3 ,Er3 ,Yb3 ,配体H2L=N,N-双(邻羟苯亚甲基)-3,6-二氧杂-1,8-二氨基辛烷,Mq为8-羟基喹哪啶.采用元素分析、红外光谱(IR)、紫外-可见吸收光谱(UV-vis)、热重-差热分析(TG-DTG)等手段对配合物的组成结构进行了表征.测定了3种新型结构稀土三元配合物在不同温度(77 K和300 K)时的近红外发光光谱.     

时滞对磁通耦合及化学耦合神经元分岔及同步的影响

以化学突触耦合神经元模型为基础,讨论了抑制性及兴奋性条件下达到同步的区别及同步的类型。并根据磁通耦合对神经元放电的影响,讨论了具有时滞、磁通耦合和化学耦合Morris-Lecar (ML)神经元模型的放电状态、分岔类型及其同步情况。发现具有磁通耦合和化学耦合ML神经元系统在不同参数下会产生丰富的逆倍周期分岔或加周期分岔行为。而时滞的引入,虽然可以增加系统的周期性,但同时也会破环系统同步。相反,适当的耦合强度能够增加同步。     

Studies on Chemical Constituents of Polygonum Ciliinerve Ohwi

Three new apianen lactones Maomailiaoine I ( 1 ), Maomailiaoine II ( 2 ) and Maoimaliaoine III ( 3 ), together with one known apianen lactone, five known flavonoids and three other known compounds were isolated from Polgonum ciliinerve Ohwi. Their structures were deduced from spectroscopic methods and 2D NMR techniques.     

Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in Nafion-RTIL composite film

The composite film based on Nafion and hydrophobic room-temperature ionic liquid (RTIL) 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim] PF₆) was explored. Here, Nafion was used as a binder to form Nafion-ionic liquids composite film and help [bmim] PF₆ effectively adhered on glassy carbon (GC) electrode. X-ray photoelectron spectroscopy (XPS), cyclic voltammtery (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize this composite film, showing that the composite film can effectively adhere on the GC electrode surface through Nafion interacting with [bmim] PF₆ and GC electrode. Meanwhile, doping [bmim] PF₆ in Nafion can also effectively reduce the electron transfer resistance of Nafion. The composite film can be readily used as an immobilization matrix to entrap horseradish peroxidase (HRP). A pair of well-defined redox peaks of HRP was obtained at the HRP/Nafion-[bmim] PF₆ composite film-modified GC electrode through direct electron transfer between the protein and the underlying electrode. HRP can still retain its biological activity and enhance electrochemical reduction towards O₂ and H₂O₂. It is expected that this composite film may find more potential applications in biosensors and biocatalysis.     

火焰原子吸收法测定化妆品中的铬

采用火焰原子吸收分光光度法测定了兰州市的一些市售化妆品中铬的含量。结果表明,方法检测限(3σ)为0.003 mg/L,回收率在94%~105%之间,相对标准差小于1.3%,方法简便快速;市售多数化妆品中的铬含量超过国家标准,须引起人们的注意。     

含八齿苦味酸根的超分子苦味酸钾的合成和结构

A supramolecular complex， [Kpic]_n (pic^- is picratol， (NO₂)₃C₆H₂O^-)， has been synthesized unexpectedly in acetone solution， and characterized by elemental analysis， IR and X-ray crystallography. In the complex， the K⁺∶pic^- is 1∶1， and one K(Ⅰ) ion is surrounded by six picrate anions， one picrate anion can coordinate to six K(Ⅰ) ions. The coordination number of every potassium atom is eight. Interestingly， the picratol adopts an eight-coordinated ideal mode unreported. CCDC: 630627.