A Multi‐Component Sensor System for Detection of Amphiphilic Compounds

Many biologically important compounds are amphiphilic in character. Glycolipids, for example, represent a biologically important class of amphiphiles. Receptors and sensors for such compounds must also be amphiphilic making them a challenge to prepare. Here, a cucurbit[8]uril (CB[8])‐based sensor system has been prepared and tested for detection of amphiphilic compounds. This multi‐component system consists: a CB[8], which acts as a hydrophobic lipid receptor, a hydrophilic pyridinium‐based carbohydrate receptor, and a fluorescent indicator. The system self‐assembles in aqueous solution. The pyridinium quenches the fluorescence of the indicator giving a strong turn‐on response when it is displaced by the analyte. The sensor system was characterized by NMR, X‐ray crystallography, and fluorescence titrations.     

Ion dynamics under pressure in an ionic liquid

We investigate ion dynamics under pressure in the ionic liquid 1-butyl-1-methylpyrrolidinium bis[oxalate]borate (BMP-BOB) by conductivity relaxation measurements in the temperature range 123-300 K and varying pressures from 0.1 MPa up to 0.5 GPa. We report on the influence of pressure on the relaxation times and on the spectral shape of the conductivity relaxation process. We also analyze the pressure dependence of the glass transition temperature and find that the dynamic response under pressure in this ionic liquid shows remarkable similarities to nonionic glass formers. The main relaxation process shows temperature-pressure superposition while a secondary relaxation process, very weakly depending on pressure, is observed. The spectral shape of the main relaxation broadens with increasing pressure or decreasing temperature, but is found to be the same when the relaxation time is the same, independently of the particular pressure and temperature values.     

The Si-Si effect on ionization of beta-disilanyl sulfides and selenides

The ionization energies of conformationally constrained, newly synthesized beta-disilanyl sulfides and selenides were determined by photoelectron spectroscopy. These ionization energies reflect substantial (0.53-0.75 eV) orbital destabilizations. The basis for these destabilizations was investigated by theoretical calculations, which reveal geometry-dependent interaction between sulfur or selenium lone pair orbitals and sigma-orbitals, especially Si-Si sigma-orbitals. These results presage facile redox chemistry for these compounds and significantly extend the concept of sigma-stabilization of electron-deficient centers.     

On zeros of solutions of linear differential equations

We consider linear differential equations with regular coefficients in $\text{¦ z ¦ < 1}$. We obtain sufficient conditions for all the solutions of these equations to vanish a given number of times at the most. First the results are obtained for differential equations of second order, then for differential equations of nth order, n > 2.     

Neighborly combinatorial 3-manifolds with 9 vertices

A complete classification is given for neighborly combinatorial 3-manifolds with 9 vertices. It is found that there are 51 types, only one of which is not a sphere.     

Size-selective molecular transport through silica colloidal nanopores

Diffusion rate of dye-labelled PAMAM dendrimers through free-standing silica colloidal crystals was studied as a function of the dendrimer generation and nanopore size to determine the transport selectivity.     

Local Exact Controllability for the One-Dimensional Compressible Navier–Stokes Equation

In this paper we deal with the isentropic (compressible) Navier-Stokes equation in one space dimension and we adress the problem of the boundary controllability for this system. We prove that we can drive initial conditions which are sufficiently close to some constant states to those constant states. This is done under some natural hypotheses on the time of control and on the regularity on the initial conditions.     

在材料研制中的连续介质细观力学有限元建模现状评论（译文）

评述了机械载荷下材料力学行为有限元模拟的先进技术.分析 了考虑材料微观及细观结构情况下，对材料变形、损伤、断裂进行模 拟时各种方法的优缺点及发展前景.阐述了对材料行为模拟方法的发 展，包括基本的及先进的方法，如体胞方法、真实结构模拟、粘结区 模型等.分析了在先进新材料的开发中运用有限元方法的可能性     

Refined Dugdale plastic zones of an external circular crack

The refined Dugdale-type plastic zones ahead of an external circular crack, subjected to a uniform displacement at infinity, are evaluated both analytically and numerically. The analytical method utilizes potential theory in classical linear elasticity with emphasis on the contrast from the internal crack problem. A closed-form solution to the mixed boundary problem is obtained to predict the length of the plastic zone for a Tresca yield condition. The analytical solution is also used to benchmark the results obtained from the numerical method, which show good agreement. Through an iterative scheme, the numerical technique is able to estimate the size of crack tip plasticity zone, which is governed by the non-linear von Mises criterion. The relationships between the applied displacement and the length of the plastic zone are compared for the different yielding conditions. Computational modeling has demonstrated that the plastic constraint effect based on the true yield condition can significantly influence the load-bearing capacity. It is also discovered from the comparative study that the stress components predicted by the three different yield conditions may differ notably; however, the stress triaxiality in the ligament region has only small deviations. The proposed study may find applications in predicting the plastic flow in a circumferentially notched round bars under tension.