CuAlNi单晶应力诱发马氏体相变与微结构演化的实验观察与分析

基于CuAlNi形状记忆合金单晶的一维准静态拉伸实验,着重研究相变过程中条带状马氏体的微观结构.通过金相显微镜对整个试样表面进行拍照,并利用图像处理技术和均匀化的方法,提取到了不同载荷下马氏体的含量(相分量)和条带的数量(界面数)在试样各处的分布与变化情况,找到了加载和卸载过程中相变微结构的演化规律,从而实现了对条带状马氏体相变微结构的量化处理.     

Metallic mono-layered C4N as a potential anode material for Na-ion batteries: A first-principles investigation

First-principles calculations based on density functional theory were used to study the adsorption behaviors of Na on metallic mono-layered C₄N as electrode materials for Na-ion batteries. The adsorption energy of Na atom was calculated to be 2.05 eV, which is much higher than Na bulk cohesive energy and sufficiently ensure stability and safety. It is worth noting that the Dirac-type band structure of mono-layered C₄N has a ultrahigh capacity of 1945.89 mAh/g for Na-ion batteries anode in theory. Remarkably, 2D C₄N has a low diffusion barrier 0.071 and 0.075 eV for path I and path II, respectively. The average open circuit voltage is 1.383 eV when nine Na ions adsorbed on one side of mono-layered C₄N. All the excellent properties show that the mono-layered C₄N will be a potential development of anode materials for Na-ion batteries.     

Investigation of Pr2NiMnO6‐Ce0.9Gd0.1O1.95 composite cathode for intermediate-temperature solid oxide fuel cells

Journal of Solid State Electrochemistry - The electrochemical performance of Pr2NiMnO6 (PNMO)-xCe0.9Gd0.1O1.95 (CGO) (x = 0–40 wt%) composite oxides as...     

Synthesis,self-assembly and pH sensitivity of a novel fluorinated triphilic block copolymer

A novel fluorinated triblock copolymer incorporating 2-ethylhexyl methacrylate (EHMA),tert-butyl methacrylate (tBMA) and 1H,1H,2H,2H-perfluorodecyl acrylate (FA) (PEHMA-b-PtBMA-b-PFA) was first synthesized using three successive reversible addition fragmentation chain transfer (RAFT) polymerization and the subsequent hydrolyzing at acidic condition.The as-fabricated triblock copolymer exhibited an interesting morphology evolution from the multi-compartment rod-like structure to spherical structure along with the addition of a selective solution.At the same time,a visible phase separation domain could be seen in the core area due to the existence of fluorocarbon segments.Furthermore,the selfassembly behavior of the triphilic copolymer at different pH was also verified by transmission electron microscopy,as well as the dynamic light scattering.These stimuli-responsive multi-compartment nanostructures may have potential applications in drug delivery.     

Wide bandgap conjugated polymers based on bithiophene and benzotriazole for bulk heterojunction solar cells: Thiophene versus thieno[3,2-b]thiophene as π-conjugated spacers

Two wide bandgap (WBG) conjugated polymers, P2T-DTTTAZ and P2T-DTTAZ, with donor-π-acceptor (D-π-A) structures was designed and synthesized, utilizing thieno[3,2-b]thiophene (TT) and/or thiophene (T) units as π-bridge in conjugated polymer backbone. And, the wider optical band gap (E_g) of approximately 1.98 eV for P2T-DTTTAZ and 2.09 eV for P2T-DTTAZ were observed. Obviously, replacing T unit with larger conjugated plane TT unit as π-bridges, P2T-DTTTAZ resulted in the red shifted absorption and the reduced band gap, compared with these of P2T-DTTAZ. The polymer solar cells (PSCs) with an inverted device structure based on P2T-DTTTAZ or P2T-DTTAZ as donor and [6,6] phenyl-C₆₁ butyric acid methyl ester (PC₆₁BM) as acceptor were assembled and the photovoltaic properties were also investigated. The power conversion efficiencies (PCEs) of 1.57% for P2T-DTTTAZ and 1.25% for P2T-DTTAZ were obtained.     

Separation and purification of six components from the roots of Rheum officinale Baill. by supercritical fluid chromatography

The dried roots of Rheum officinale Baill., named Dahuang in Chinese, has many pharmacological effects and has been widely used for the treatment of many diseases. To develop a harmless and eco-friendly method for the separation of components in Dahuang is of great interest for quality control and pharmacological study of Dahuang. A method for separation and purification of components in Dahuang using supercritical fluid chromatography (SFC) is established in this work. Samples were prepared by extraction of Dahuang powders with 20% H₂SO₄ and benzene under reflux. The extracts were obtained by evaporating benzene extracts and separating by SFC on YMC-Diol column using supercritical CO₂ with CH₃OH 4% (v/v) as the modifier. The flow rate of the mobile phase was 15?mL/min, the column pressure was 13?MPa, and the column temperature was 318?K. Cinnamic acid and five kinds of hydroxyanthraquinones including rhein, emodin, aloe emodin, chrysophanol, and physcion were obtained by SFC. The purities of the obtained compounds were all above 97% as determined by high performance liquid chromatography and their chemical structures were identified by nuclear magnetic resonance and mass spectrum. The thermodynamics of chromatographic process was also studied and it revealed that the SFC separation process of these compounds on YMC-Diol column was controlled by enthalpy.     

Aptamer based surface plasmon resonance sensor for aflatoxin B1

The authors describe a surface plasmon resonance (SPR) based aptasensor for the carcinogenic mycotoxin aflatoxin B1 (AFB1) in a direct assay format. The aptamer is immobilized on the surface of a commercial sensor chip, and the SPR signal increases on binding of AFB1. The sensor chip can be fully regenerated by passing a flow of buffer over it upon which bound AFB1 dissociates from the aptamer. The biosensor works in the 0.4 nM to 200 nM AFB1 concentration range and has a 0.4 nM detection limit. It allows AFB1 to be determined in complex samples such as diluted red wine and beer. The assay is sensitive, and the chip is easily regenerated and stable. The method therefore overcomes certain limitations of antibody-based SPR assays and of competitive SPR assays for AFB1.

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Graphical abstract Schematic presentation of the assay: Aptamer is coated on the chip of SPR, and the binding between aflatoxin B1 (AFB1) and the aptamer on chip causes SPR responses, allowing sensitive detection of AFB1.

     

利用XPS研究Y-Ba-Cu-O超导体(Ⅱ)

1.超导体表面的化学态(Ⅱ) 从结合能数据来看,Y(1)和Cu的结合能非常近似于相应氧化物Y_2O_3和CuO。然而表征超导体的Ba(1)和O(1)有些特殊,Ba在周期表中为强金属性元素,极易丢失(6s)~2电子,即使在金属中也要电离成导带电子,使得金属Ba~0和离子Ba~(+2)结合能十分相似,甚至金属钡结合能反而大一点,然而和众多的钡化合物相比,超导体中Ba(1)的结合能偏低,似乎在电子的受授过程中,有较多电子偏向于钡,另外也可能由于超导体的Ba与所有晶格氧     

Synthesis and self-assembly of monodisperse silver-nanocrystal-doped silica particles

A simple method based on the St?ber reaction was developed to prepare silver-nanocrystal-doped silica composite particles. The silane coupling agent N-[3-(trimethoxysilyl)dropyl]ethylene diamine (TSD) incorporated Ag+ into a siloxane framework and a further chemical reducer reduced Ag+ to silver nanoparticles. TEM images showed that, in the presence of TSD, silver nanocrystals (fcc) of 2-8 nm were homogeneously doped in the silica particles, which showed a typical surface plasmon resonance (SPR) peak. The as-prepared Ag/SiO2 composite particles can be self-assembled into long-range ordered lattices (or photonic crystals) over large areas.     

用MATLAB回归非线性模型参数

非线性模型参数回归难度大,需要一定的数学基础,用MATLAB回归分析工具箱可直接进行非线性回归,计算简单准确,并能给出直观的拟合曲线图。