基体匹配–电感耦合等离子体原子发射光谱法测定新型抗菌不锈钢中镓

建立电感耦合等离子体原子发射光谱法测定含镓抗菌不锈钢中镓含量的方法.样品用盐酸和硝酸溶解,在优化的仪器条件下,选择417.206 nm作为分析谱线.采用基体匹配法绘制工作曲线,用以消除基体铁的基体效应;采用铁基体为校准空白,用以消除铁基体的光谱干扰.标准工作溶液中镓光谱强度与基体空白溶液中镓光谱强度之差与镓的质量分数在...     

Plasmonics properties of nano-torus: An FEM method

Nano-torus particles are promising in nano-photonics applications. In this paper, we investigate the plasmonics resonant spectrum of torus and the corresponding horizontal and vertical dimers with the finite element method (FEM) based on strict electromagnetic theory. Compared with sphere, single torus and horizontal dimer under perpendicular polarization are characterized with narrower line width and wider tunability throughout visible and infrared frequencies. These properties make single torus and horizontal dimer suitable for high sensitivity sensing. Furthermore, Purcell factor and local field enhancement of horizontal dimer which are important to high efficient single photon devices are one order of magnitude higher than those of single torus respectively. However, vertical dimer under perpendicular polarization has no above advanced characteristics.     

Porous redox-active Cu2O-SiO2 nanostructured film: Preparation, characterization and application for a label-free amperometric ferritin immunosensor

A novel Cu₂O-SiO₂ nanostructured particle was synthesized by a solution-phase method and was adopted for construction of a label-free amperometric immunosensor. The porous Cu₂O-SiO₂ nanoparticles had good redox electrochemical activity, large surface-to-volume ratio, film-forming ability and high stability. The physical morphology and structure of Cu₂O-SiO₂ nanoparticles were examined by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The chemical component of Cu₂O-SiO₂ was confirmed by X-ray photoelectron spectroscopy (XPS) and auger electron spectra (AES). The electrode modification process was probed by cyclic voltammetry (CV) and the performance of the immunosensor was studied by differential pulse voltammetry (DPV) measurements. To improve the analytical characteristics of the immunosensor, the experimental conditions were optimized. The immunosensor exhibited a good response to ferritin in ranges from 1.0 to 5.0 and 5.0 to 120.0 ng mL⁻¹ with a detection limit of 0.4 ng mL⁻¹. The fabricated immunosensor could make a low-cost, sensitive, quantitative detection of ferritin, and would have a potential application in clinical immunoassays.     

Molecular dynamics simulations of atomic assembly in the process of GaN film growth

Molecular dynamics simulations using a Coulomb–Buckingham potential have been used to investigate the process of wurtzite GaN films growth, including the appearance of films in early stage, regulation of growth, structure of the surface and the dynamic features. The simulations show that the N atoms and Ga atoms are absorbed on the lattice of substrate and take on a distinct sandwich structure. Time evolution of the mean square displacements and diffusion coefficient of the deposited atoms are observed, the results show that the clusters will become stable with the increase of time steps and the atoms reach the initial stable state after 25 ps; N atoms reach the equilibrium positions more quickly than Ga atoms. It is proved by radial distribution function and the ratio of vacancy of every deposited layer that the crystalline characters of the films will become better as the time steps increase and weaker from bottom to top.     

“水窗”波段类Li离子各电离态的电离能

用相对论多组成Ｄｉｒａｃ－Ｆｏｃｋ方法计算了“水窗”波段类Ｌｉ离子各电离态的电离能，这些能量对于优化复合泵浦软Ｘ射线激光机制具有重要意义。     

Coarse-grained Dynamics Simulation in Polymer Systems: from Structures to Material Properties

Polymers are widely used in our daily life and industry because of their intrinsic characteristics, such as multi-functionality, low cost, light mass, ease of processability, and excellent chemical stability. Polymers have multiscale space-time properties, which are mainly reflected in the fact that the properties of polymer systems depend not only on chemical structure and molecular properties, but also to a large extent on the aggregation state of molecules, that is, phase structure and condensed state structure. Thanks to the continuous development of simulation methods and the rapid improvement of scientific computation, computer simulation has played an increasingly important role in investigating the structure and properties of polymer systems. Among them, coarse-grained dynamics simulations provide a powerful tool for studying the self-assembly structure and dynamic behavior of polymers, such as glass transition and entanglement dynamics. This review summarizes the coarse-grained models and methods in the dynamic simulations for polymers and their composite systems based on graphics processing unit(GPU) algorithms, and discusses the characteristics, applications, and advantages of different simulation methods. Based on recent studies in our group, the main progress of coarse-grained simulation methods in studying the structure, properties and physical mechanism of polymer materials is reviewed. It is anticipated to provide a reference for further development of coarse-grained simulation methods and software suitable for polymer research.     

Enantioselective Pd-catalyzed allylic alkylation of indoles by a new class of chiral ferrocenyl P/S ligands

Chiral ferrocenyl heterobidentate P/S ligands bearing both central and planar chirality were prepared from (S)-Ugi's amine via a three-step modular synthesis. Through systematic screening and optimization, L8 was found to be the best ligand for Pd-catalyzed asymmetric allylic alkylation of indoles with ee's up to 96% being attained.     

BRC共振能应用于定量探讨Diels—Alder反应

应用生成物和反应物之间的共振能差(△REBRC)可以判定多环苯型烃与马来酐起Diels—Alder反应的活性和确定反应中心。△REBRC和反应的二级速度常数的对数之间存在线性关系（r=0.9785。s=0.3897）,故可从定角度阐明线式稠合及角式稠合对反应活性的不同影响。     

A new perturbation to a critical elliptic problem with a variable exponent

In this paper, we study the following critical elliptic problem with a variable exponent:■,where ■, and ? is a smooth bounded domain in R^N(N≥4). We show that for small enough, there exists a family of bubble solutions concentrating at the negative stable critical point of the function a(x). This is a new perturbation to the critical elliptic equation in contrast to the usual subcritical or supercritical perturbation, and gives the first existence result for the critical elliptic probl...     

Curing theory of A_f-A_g type free radical polymerization (Ⅱ)——Characterization of network structural parameters

By means of the polymer statistical theory, the A_f-A_g type nonlinear free radical polymerization is investigated to give the number of effective elastic chains, the number of effective elastic mers and the average length for the elastic chains. The corresponding quantities for the dangling chains, the number of effective cross-linkage and the modulus are also obtained. Furthermore, the number- and weight-fractions of elastic chains are deduced.