海藻酸壳聚糖可塑性支架材料的制备及表征

利用海藻酸钠和壳聚糖2种原料, 采用阴阳离子静电复合原理, 通过滴注法层层自组装成可搭载药物的缓释微球, 再按一定比例与海藻酸钠-壳聚糖溶液混合制成缓释微球型支架材料, 将缓释微球结构嵌入疏松多孔海绵状结构中. 研究了缓释微球的组分比对缓释微球型支架材料的孔隙率、 收缩率、 亲水性及降解性能的影响; 扫描电子显微镜照片显示, 微球结构相对完整, 多孔海绵状结构孔径为140~200 μm; 支架浸出液细胞毒性检测实验组对照组未见差异. 缓释微球体积所占比例即组分比为10%的缓释微球型支架材料孔隙率最高为68.2%~70.8%, 亲水性最好, 收缩率最低为4.4%~5.2%; 支架降解速率随缓释微球组分比升高而减慢, 组分比为20%的缓释微球型支架材料综合性能更优; 缓释微球型支架材料冻干成型前为液态, 具有良好可塑性. 缓释微球型支架材料为缓释系统与多孔支架材料有机结合提供了新思路.     

Interaction of NO2 with Model NSR Catalysts: Metal–Oxide Interaction Controls Initial NOx Storage Mechanism

Using scanning tunneling microscopy (STM), molecular‐beam (MB) methods and time‐resolved infrared reflection absorption spectroscopy (TR‐IRAS), we investigate the mechanism of initial NO_x uptake on a model nitrogen storage and reduction (NSR) catalyst. The model system is prepared by co‐deposition of Pd metal particles and Ba‐containing oxide particles onto an ordered alumina film on NiAl(110). We show that the metal–oxide interaction between the active noble metal particles and the NO_x storage compound in NSR model catalysts plays an important role in the reaction mechanism. We suggest that strong interaction facilitates reverse spillover of activated oxygen species from the NO_x storage compound to the metal. This process leads to partial oxidation of the metal nanoparticles and simultaneous stabilization of the surface nitrite intermediate.     

Sobolev方程的连续时空有限元方法

本文研究Sobolev方程的连续时空有限元方法.首先建立Sobolev方程的连续时空有限元格式,然后证明了解的存在唯一性和稳定性并给出连续时空有限元解各种范数下的误差估计.最后给出数值算例来验证理论分析的正确性,并进一步说明本文所建立的格式关于时间可以得到比传统有限元方法更高的精度.     

Conductivity Measurements of a Con jugated-Polymer Single crystal at Lower Temperature

The conductivities in bis-(p-toluene sulfonate) or 2,4-hexa-diyne-1,6-diol(TS) and its polymer PTS single crystal were measured by means of a special device at a range of temperature from 77K to 373K (353K for TS) . Anomalies of the conductivity of TS and PTS along c-axes which are the directions of PTS at the temperature corresponding to their low temperature phase transition were observed. The temperature of phase transition in TS obtained from anomalies' of conductivity are 163K and 208K.     

用铝灰生产聚氯化铝的反应动力学研究

本文对以工业废渣铝灰与盐酸反应制取聚氯化铝的反应进行了动力学研究。在0.5～3N的盐酸浓度范围内,反应速度与盐酸浓度的1.5次方成正比,反应的表观活化能为48kJ/mol-H₂。以某厂提供的铝灰为试样,测得动力学方程式为 dH₂/dt=6.2×10²·exp(-5.8×10³/T)·W·C_Hcl^1.5(mol/s)。     

证券市场多次最优停止:技术分析

本文提出证券市场多次最优停止的理论和方法,并应用此理论对证券市场广泛应用的技术分析工具：阻力线和支撑线提出解释     

Effect of the Duty Cycle of Flower-like Silver Nanostructures Fabricated with a Lyotropic Liquid Crystal on the SERS Spectrum

Surface-enhanced Raman scattering (SERS) has been widely reported to improve the sensitivity of Raman spectra. Ordinarily, the laser is focused on the sample to measure the Raman spectrum. The size of the focused light spot is comparable with that of micro-nano structures, and the number of micro-nano structures contained in the light spot area (defined as duty cycle) will severely affect the spectrum intensity. In this study, flower-like silver nanostructures were fabricated with a soft lyotropic liquid crystal template in order to investigate the effect of duty cycle. They were observed under a scanning electron microscope, and their spectrum enhancement factor was computed with the obtained Raman spectrum. Then, their duty cycles were measured using a SERS substrate at different locations. A formula was derived to represent the relation between the duty cycle of the nanoflowers and the Raman spectral intensity. This work could promote the actual applications of SERS in high-sensitivity spectrum testing.     

Neoengleromycin,a Novel Compound from Engleromyces goetzii

A novel N‐containing compound, neoengleromycin ( 1 ) was isolated from the fruiting bodies of the ascomycete Engleromyces goetzii together with two known cytochalasins: cytochalasin D ( 2 ) and 19,20‐epoxycytochalasin D ( 3 ). Structures were established by spectroscopic (including 2D‐NMR) and chemical means. Neoengleromycin ( 1 ) possesses the rare structure of an N‐substituted hydroxamic acid and represents a new type of natural products.     

Electrospinning Synthesis of Porous NiCoO2 Nanofibers as High‐Performance Anode for Lithium‐Ion Batteries

Nanostructured ternary/mixed transition metal oxides have attracted considerable attentions because of their high‐capacity and high‐rate capability in the electrochemical energy storage applications, but facile large‐scale fabrication with desired nanostructures still remains a great challenge. To overcome this, a facile synthesis of porous NiCoO₂ nanofibers composed of interconnected nanoparticles via an electrospinning–annealing strategy is reported herein. When examined as anode materials for lithium‐ion batteries, the as‐prepared porous NiCoO₂ nanofibers demonstrate superior lithium storage properties, delivering a high discharge capacity of 945 mA h g^?1 after 140 cycles at 100 mA g^?1 and a high rate capacity of 523 mA h g^?1 at 2000 mA g^?1. This excellent electrochemical performance could be ascribed to the novel hierarchical nanoparticle‐nanofiber assembly structure, which can not only buffer the volumetric changes upon lithiation/delithiation processes but also provide enlarged surface sites for lithium storage and facilitate the charge/electrolyte diffusion. Notably, a facile synthetic strategy for fabrication of ternary/mixed metal oxides with 1D nanostructures, which is promising for energy‐related applications, is provided.