关于BCK-代数的模糊理想和超积

通过使用超滤子的概念以及所讨论的模糊理想的相应性质,提出了超积BCK-代数和BCK-代数模糊子集的模糊超积.     

Temperature dependence of photonic crystals based on thermoresponsive magnetic fluids

The influence mechanisms of temperature on the band gap properties of the magnetic fluids based photonic crystals are elaborated. A method has been developed to obtain the temperature-dependent structure information (A_sol/A) from the existing experimental data and then two critical parameters, i.e. the structure ratio (d/a) and the refractive index contrast (Δn) of the magnetic fluids photonic crystals are deduced for band diagram calculations. The temperature-dependent band gaps are gained for z-even and z-odd modes. Band diagram calculations display that the mid frequencies and positions of the existing forbidden bands are not very sensitive to the temperature, while the number of the forbidden bands at certain strengths of magnetic field may change with the temperature variation. The results presented in this work give a guideline for designing the potential photonic devices based on the temperature characteristics of the magnetic fluids based photonic crystals and are helpful for improving their quality.     

钛酸铋钠无铅压电陶瓷的研究进展

本文简要介绍了研究无铅压电陶瓷材料的必要性,从Bi_0.5Na_0.5TiO₃压电陶瓷材料的结构、改进机理、剩余极化强度、矫顽场和制备工艺等角度出发,论述了Bi_0.5Na_0.5TiO₃无铅压电陶瓷材料的不足和亟待解决的基本问题。综述了Bi_0.5Na_0.5TiO₃无铅压电陶瓷研究的新方法和新工艺,即改进Bi_0.5Na_0.5TiO₃的一些最新理论设想、实验成果和工艺步骤,以企本文对国内外相关研究者有所裨益。     

Sulfonated graphene oxide: the new and effective material for synthesis of polystyrene-based nanocomposites

The new sulfonated graphene oxide (S-GO) was prepared and firstly used as effective materials for the synthesis of polystyrene/graphene nanocomposites via Pickering emulsion polymerization. The functionalized, chemically modified GO nanosheets were obtained via facile covalent functionalization with a reactive surfactant, sulfanilic acid. It was found that Pickering emulsion could be formed by simple self-assembly method using the S-GO as a stabilizer (just need 1 wt% relative to the oil phase), which could be adsorbed at the oil–water interface to stabilize the emulsion effectively. After the Pickering emulsion polymerization of styrene, the polystyrene/S-GO nanocomposites were prepared successfully. It is noteworthy that the S-GO not only could be used as a highly effective surfactant for styrene monomers but also could be homogeneously dispersed and incorporated into the polymeric matrix.     

炭黑吸附法制备掺杂镨TiO2纳米粉体及其光催化性能

以硝酸镨为掺杂的前驱物,钛酸异丙酯为TiO2的前驱物,通过炭黑吸附高温水热法制得掺杂镨的量为0.07%的纳米Pr3+/TiO2粉体。分别采用热重/差热分析(TG-DTA)、X射线衍射(XRD)、扫描电镜(SEM)、紫外可见分析(UV-VIS)和比表面积吸附(BET)对不同焙烧温度下所得粉体的物相、颗粒度、分散性及光吸收性能进行表征和分析。实验结果表明:炭黑的吸附阻止了粉体在干燥和煅烧阶段的团聚和烧结,制得的Pr3+/TiO2纳米粉体团聚较少,呈现良好的分散性,颗粒均匀,经500℃焙烧,得到纳米粉体平均颗粒直径为18 nm,比表面积为78.08 g.m-2。光催化降解实验表明,炭黑吸附后TiO2的光催化活性在一定时间内比没有炭黑的提高了将近2倍,在紫外灯照射下Pr3+/TiO2能在60 min内对亚甲基蓝的降解率达到93%。     

瑞利激光雷达探测南京上空平流层大气温度

为了解平流层大气温度变化规律,利用瑞利-拉曼-米散射激光雷达对南京上空平流层温度进行长期观测,对观测数据的分析表明:夜晚平流层温度受到重力波的影响,重力波破碎会导致局部温度升高,温度相对变化可以达到12%;在季节变化的过渡月份(4月和10月),平流层中低层温度会有所升高,对应的平流层高层温度降低;平流层温度月变化方面,除局部由于行星星际波的影响外,各月份平流层温度整体上相对比较稳定,激光雷达所测大气温度与大气模式温度具有一定的差别。最后,利用平流层温度廓线提取了重力波信息。     

Analysis of allergens in tubeimu saponin extracts by using rat basophilic leukemia 2H3 cell‐based affinity chromatography coupled to liquid chromatography and mass spectrometry

An affinity two‐dimensional chromatography method was developed for the recognition, separation, and identification of allergic components from tubeimu saponin extracts, a preparation often injected to treat various conditions as indicated by traditional Chinese medicine. Rat basophilic leukemia‐2H3 cell membranes were used as the stationary phase of a membrane affinity chromatography column to capture components with affinity for mast cells that could be involved in a degranulation reaction. The retained components were enriched and analyzed by membrane affinity chromatography with liquid chromatography and mass spectrometry via a port switch valve. Suitability and reliability of the method was investigated using appropriate standards, and then, the method was applied to identify components retained from tubeimu saponin extracts. Tubeimoside A was identified in this way as a potential allergen, and degranulation assays confirmed that tubeimoside A induces RBL‐2H3 cell degranulation in a dose‐dependent manner. An increase in Ca²⁺ influx indicated that degranulation induced by tubeimoside A is likely Ca²⁺ dependent. Coupled with the degranulation assay, RBL‐2H3 cell‐based affinity chromatography coupled with liquid chromatography and mass spectrometry is an effective method for screening and identifying allergic components from tubeimu saponin extracts.     

DSP based receiver implementation for OFDM acoustic modems

Significant progress has been made recently on the use of multicarrier modulation in the form of orthogonal frequency division multiplexing (OFDM) for high data rate underwater acoustic communications. In this paper, we present implementation results of OFDM acoustic modems under different settings with either one or two parallel data streams transmitted, whose data rate is 3.2 KB/s or 6.4 KB/s, respectively, with QPSK modulation, rate-1/2 channel coding, and signal bandwidth of 6 kHz. To achieve real time operation, the processing time for each OFDM block shall be (much) less than the block duration of 210 ms. We first implement the receiver algorithms on a floating point TMS320C6713 DSP development board, running at 225 MHz. With convolutional coding, the per-block processing time is about 38 ms and 77 ms for single-input single-output (SISO) and multi-input multi-output (MIMO) settings, respectively, where there are two transmitters and two receivers in the latter case. With nonbinary low-density parity-check (LDPC) coding, which gains about 2 dB in error performance relative to convolutional coding, the per-block processing time increases to 50 ms and 101 ms for SISO and MIMO settings, respectively. We have also implemented the receiver algorithms using a fixed-point TMS320C6416 DSP development board, where the DSP core runs at 1 GHz. The per-block processing time reduces by two thirds with negligible performance degradation.     

A rotating disk electrode study of the particle size effects of Pt for the hydrogen oxidation reaction

By using a catalyst-lean thin-film RDE method, the fast kinetics of the hydrogen oxidation reaction (HOR) on highly dispersed Pt nanoparticle electrocatalysts can be determined, free from the interference of the mass transport of H(2) molecules in solution. Measurements with carbon-supported Pt nanoparticles of different sizes thus allow revealing the particle size effect of Pt for the HOR. It is shown that there is a "negative" particle size effect of Pt on the kinetics of HOR, i.e., the exchange current density j(0) decreases with the increased dispersion (i.e. decreased mean particle size). A maximum mass activity of Pt for the HOR is found at particle sizes of 3-3.5 nm. The observed particle size effect is interpreted in terms of the size dependent distribution of surface atoms on the facets and edges, which is implied by the voltammetric responses of Pt/C catalysts with differently sized Pt particles. The accompanied decrease in the HOR activity with the increase in the edge atom fraction suggests that the edge atoms on the surface of Pt nanoparticles are less active for the HOR than those on the facets.