Selective hydrogenation of acetylene over Pd/CeO2

Five hundred ppm Pd/CeO₂ catalyst was prepared and evaluated in selective hydrogenation of acetylene in large excess of ethylene since ceria has been recently found to be a reasonable stand-alone catalyst for this reaction. Pd/CeO₂ catalyst could be activated in situ by the feed gas during reactions and the catalyst without reduction showed much better ethylene selectivity than the reduced one in the high temperature range due to the formation of oxygen vacancies by reduction. Excellent ethylene selectivity of ~100% was obtained in the whole reaction temperature range of 50°C–200°C for samples calcined at temperatures of 600°C and 800°C. This could be ascribed to the formation of Pd_xCe_1−xO_2−y or Pd-O-Ce surface species based on the X-ray diffraction and X-ray photoelectron spectroscopy results, indicating the strong interaction between palladium and ceria.     

微反应器中十二烷基苯液相SO_3磺化过程

石油磺酸盐和重烷基苯磺酸盐是三次采油用重要阴离子表面活性剂,其主要成分是烷基苯磺酸盐。本研究以十二烷基苯(DDB)液相SO3磺化为模型反应,研究微反应器内的烷基苯磺酸合成反应过程特性,考察了液体流量、反应温度、磺化剂中SO3含量、反应通道长度、SO3与十二烷基苯物质的量比、微反应器结构、搅拌时间等参数的影响。结果表明,十二烷基苯磺化过程受传质控制,微反应器对反应初始阶段的强化作用明显,在SO3与十二烷基苯物质的量比为1.1时,采用微反应器与釜式反应器串联模式合成十二烷基苯磺酸,收率高达93.7%,为微反应器生产重烷基苯磺酸的路线提供了重要基础。     

Preparation of grape seed polypeptide and its calcium chelate with determination of calcium bioaccessibility and structural characterisation

Grape seed polypeptide (GSPP) was obtained by liquid fermentation with Bacillus subtilis TK15.015 from waste grape seed pomace. Its chelation ability with calcium ions was excellent. Simulation of in vitro gastrointestinal digestion showed that GSPP and calcium chelate (GSPP-Ca) slowly released calcium and decreased stomach stimulation. The solubility and transmission rate of GSPP-Ca after digestion in the gastrointestinal tract for 8 h maintained high levels of 74.4% and 46.4%, respectively, which far exceeded the levels achieved by other calcium supplements. Structural characterisation showed that calcium ions mainly react with binding sites present in peptides such as carboxyl oxygen, hydroxyl oxygen, amino nitrogen and amide bonds. GSPP-Ca may be a state in which a calcium-encapsulating complex formed, leaving calcium ions in a soluble state, suggesting its possible use as a high-quality calcium supplement.     

Influence of pore structure on the gravity separation performance of fine lignite

Influence of lignite porosity on the density fluctuation and subsequent beneficiation efficiency was studied. Using copper as tracer element, SEM+EDS was used to study the wetting rate of medium to particles. Furthermore, the particle quality changes before and after the wetting was analyzed. Separation experiments were carried out to verify the hypothesis. Results show that the wetting process is less than three seconds and there is no significant relationship between the quality growth rate and the particle density, which leads to the irregular change of particle density. Separation experiment proved the low separation efficiency and high content of mismatch particles.     

Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter

Microfluidic fluorescence‐activated cell sorters (μFACS) have attracted considerable interest because of their ability to identify and separate cells in inexpensive and biosafe ways. Here a high‐performance μFACS is presented by integrating a standing surface acoustic wave (SSAW)‐based, 3D cell‐focusing unit, an in‐plane fluorescent detection unit, and an SSAW‐based cell‐deflection unit on a single chip. Without using sheath flow or precise flow rate control, the SSAW‐based cell‐focusing technique can focus cells into a single file at a designated position. The tight focusing of cells enables an in‐plane‐integrated optical detection system to accurately distinguish individual cells of interest. In the acoustic‐based cell‐deflection unit, a focused interdigital transducer design is utilized to deflect cells from the focused stream within a minimized area, resulting in a high‐throughput sorting ability. Each unit is experimentally characterized, respectively, and the integrated SSAW‐based FACS is used to sort mammalian cells (HeLa) at different throughputs. A sorting purity of greater than 90% is achieved at a throughput of 2500 events s^?1. The SSAW‐based FACS is efficient, fast, biosafe, biocompatible and has a small footprint, making it a competitive alternative to more expensive, bulkier traditional FACS.     

无人机天线在雷电效应中的响应研究及性能检测

机载天线安装在无人机表面,容易成为雷电附着点,对无人机的飞行安全会产生严重威胁。 为开展相关设计,并验证设 计的有效性,针对 UHF 机载天线为研究对象,设计了片段式导流条和端口射频雷电抑制器的防护方案。 先后进行了初始先导 附着试验、外部部件瞬态感应试验、电性能测试和系统评估计算。 试验结果表明,天线损伤程度降低,片段式导流条对天线的电 性能影响不超过 0. 3 dB,射频雷电抑制器不影响驻波比、增益。 最终链路余量满足大于 3 dB 的要求,证明了设计的有效性。     

Lower down both ohmic and cathode polarization resistances of solid oxide fuel cell via hydrothermal modified gadolinia doped ceria barrier layer

Hydrothermal reaction in Cerium and Gadolinium solution as an optimization method is developed and first reported for the densification of gadolinia doped ceria, the barrier layer between Zirconia electrolyte and (La,Sr)(Co,Fe)O_3-δ cathode. This method is based on the hydrothermal reaction for nano particles in-situly grown on porous surface, to improve barrier layer density, alongside the sintering of cathode at 1075 °C. As a result, the ohmic resistance is prominently decreased by ～16.4 % at 750 °C for electrolyte supported symmetrical cell. Whereas, the cathode polarization resistance is decreased by as much as a factor of ～3 from 0.3702 Ω·cm² to 0.1325 Ω·cm² at 750 °C and $p_{O_2}=0.21atm$. Furthermore, the anode supported cell exhibits higher open circuit voltage, smaller area specific resistance, elevated performance output and less degradation. And this modified barrier layer shows reduced Sr migration in 300 h operation at 750 °C. The hydrothermal reaction is demonstrated to prepare denser and sintering-active barrier layer with faster oxygen ion transfer and better interface connection, with large-scale application prospects and cost-competitiveness.