Chemical looping gasification of cotton stalk with bimetallic Cu/Ni/olivine as oxygen carrier

Bimetallic Cu/Ni/olivine oxygen carriers (OCs) were prepared using olivine as support material for chemical looping gasification (CLG). The cyclic redox behaviors and oxygen carrying capacity (R_o) of OCs were evaluated by thermo-gravimetric analysis. The effect of Cu/Ni ratio, gasification temperature, steam to biomass ratio (S/B), oxygen carrier to biomass ratio (OC/B) on CLG of cotton stalk has been studied in a fixed bed. The OCs characterized using BET surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature-programmed reduction (TPR) to investigate the physicochemical property of OCs during CLG. Result shows that the sintering problem of OC was progressively alleviated with the increasing Cu/Ni ratio. The olivine behaves as suitable OC support with oxygen carrying capacity of 1.07%. The redox reactivity of all of the OCs kept well during multiple redox cycles. The R_o of OCs progressively increased with the Cu/Ni ratio. By comparing the product gas concentration, carbon conversion, H₂ + CO yield and gas yield over the invested OCs, the Cu9/Ni6/O was found to demonstrate better comprehensive CLG performance due to the synergistic effect of Cu and Ni. The maximum gas yield, H₂ + CO yield and carbon conversion with Cu9/Ni6/O can be obtained at the S/B of 0.8 and OC/B of 2. Compared to theoretical value, 65% of lattice oxygen has been supplied by Cu9/Ni6/O during actual CLG process. The OC displayed better reactivity due to basic crystalline phase being preserved well during multiple CLG cycles.     

模拟酶解优化鸽血红蛋白抗氧化肽酶法制备

以鸽血红蛋白为原材料，采用在线数据库ExPASy Peptide Cutter中的蛋白酶模拟酶解，通过生物信息学工具筛选多肽潜在的生物活性、溶解性、毒性和致敏性，由此预测最适宜制备鸽血红蛋白源抗氧化肽的蛋白酶。设置不同的酶解时间、酶添加量和酶解温度作为单因素，探究不同酶解条件对酶解产物水解度和DPPH自由基清除率的影响。在单因素试验的基础上，通过响应面法优化试验，探究酶解法制备鸽血红蛋白抗氧化肽的最优工艺条件。结果表明，蛋白酶K为虚拟筛选出的最佳蛋白酶，最佳的制备鸽血红蛋白抗氧化肽的工艺为鸽血红蛋白浓度1 g/100 mL、pH8、酶解时间3 h、酶添加量415.54 U/g、酶解温度65℃。在此条件下，通过验证试验得出响应值DPPH自由基清除率为（33.21±0.68）%，与预测值相差较小，故而此条件为最优工艺。采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳试验，发现最优工艺条件下鸽血红蛋白酶解后目的条带消失，进一步验证该方法为酶解鸽血红蛋白源抗氧化肽的最优工艺。     

Synthesis of defect-rich hierarchical sponge-like TiO2 nanoparticles and their improved photocatalytic and photoelectrochemical performance

Defect-rich hierarchical sponge-like TiO₂ nanoparticles were successfully synthesized via the combined one-step hydrothermal method and chemical reduction approach. SEM and TEM images showed their porous structure densely packed with even smaller TiO₂ particles, while photocatalytic results manifested their superior photocatalytic performance and high stability. The RhB solution (10 ppm) could be absolutely degraded in 60 min, and the degradation rate was twice that of the sample without the treatment by NaBH₄. Besides, the TC solution (10 ppm) could be removed by 74.3% in 20 min. PEC measurements also displayed that the photoelectrode based on such defect-rich TiO₂ nanoparticles had small resistance and improved charge transfer rate. The improved performance can be assigned to rich defects and phase junctions, which was supported by characterization results. The presence of rich defects and phase junctions could not only promote the separation of photogenerated charge carriers, but also accelerate the electron transfer, beneficial for both the photocatalytic and the PEC performance. It is expected that the obtained hierarchical sponge-like TiO₂ nanoparticles with rich defects have great potential for photocatalytic applications.     

猕猴桃蛋白酶及发酵剂对马肉发酵香肠品质特性的影响

研究发酵剂和猕猴桃蛋白酶对马肉发酵香肠品质的影响。以新鲜马肉为原料,添加发酵剂和猕猴桃蛋白酶进行发酵,检测其对马肉发酵香肠pH值、水分活度（water activity,aw）、水分含量、色差以及硫代巴比妥酸（thiobarbituric acid,TBA）值等的影响,并通过对成品进行感官评价确定发酵剂和猕猴桃蛋白酶对其感官品质的影响。结果表明：与对照组相比,发酵剂处理组（A组）显著降低了马肉发酵香肠的pH值、aw和TBA值,加快了水分含量的下降,提高了亮度值（L*）和红度值（a*）,后期黄度值（b*）略有下降;与A组相比,发酵剂和猕猴桃蛋白酶处理组（B组）提高了其pH值,降低了aw,加快了水分含量的下降,而对a*、L*、b*影响不大,对TBA值无显著影响;对成品的感官评价结果表明,B组马肉发酵香肠的口感较A组和对照组好。     

煤矿救援机器人系统运载车的设计与研究

煤矿救援机器人系统运载车设计是一个涉及多门学科的交叉研究领域。概述了煤矿救援机器人系统运载车设计中的关键技术要点,从运载车的车体设计、结构设计、关键部件设计、移动路径设计等方面探讨了煤矿救援机器人系统运载车的设计及应用开发前景。     

Preparation of rGO/AgCl QDs and its enhanced photoelectrocatalytic performance for the degradation of Tetracycline

A novel rGO/AgCl QDs composites have been obtained by an ultrasonic-assisted method for the first time. Photoelectrocatalytic (PEC) performances of the obtained samples were studied by the degradation of 20 mg/L Tetracycline (TC) under visible light irradiation with an applied bias potential of 1.5 V (vs Ag/AgCl). Degradation of TC by different processes including Photocatalysis (PC), Electrocatalysis (EC), and PEC was compared, and the effect of different bias potential on the PEC degradation of TC was discussed. Results showed that rGO/AgCl QDs composites had displayed superior PEC activity than that of pristine AgCl QDs with degrading 85.2% of TC during 120 minutes, which was about 1.5 times higher than that of AgCl QDs (33%). Besides, compared to PC and EC removal of TC, PEC process showed the highest degradation efficiency of TC (85.2%) by rGO/AgCl QDs, which was about three times and one time higher than that of PC (39.18%) and EC (20.73%) system, respectively. Moreover, the reusibility and stability of the samples were tested by five times cycling tests, and results demonstrated that the stability of bare AgCl QDs was improved after the introduction of rGO. The enhanced PEC activity and stability of the samples could be attributed to the intimate contact between rGO and AgCl QDs and external electric field, which had benefitted the formation of more active sites and accelerated electron-hole separation.     

Sonochemical preparation and photocatalytic properties of CdS QDs /Bi2WO6 3D heterojunction

Hierarchical CdS quantum dots (QDs)/ Bi₂WO₆ three-dimensional (3D) heterojunction photocatalyst was successfully synthesized by a facile green ultrasonic method for the first time. Photocatalytic activities under visible light irradiation were tested by the degradation of Rhodamine B (RhB) and tetracycline hydrochloride (TC), and the reduction of Cr(VI) in aqueous solution. As compared to pure CdS and Bi₂WO₆, CdS QDs/ Bi₂WO₆ heterojunctions manifested a significantly enhanced photocatalytic activity for these treatments. When the effect of the mass ratio of CdS QDs to Bi₂WO₆ was investigated, 3% CdS QDs/ Bi₂WO₆ heterojunction showed the highest photocatalytic efficiency: the efficiency for RhB degradation was 94.5% for 30?min and this value was about 6 times and 1.5 times higher than those of pure Bi₂WO₆ and CdS QDs. This enhancement was majorly accredited to the synergetic effect between Bi₂WO₆ and CdS QDs, which included intimate contact and matched band gap potentials between 0D CdS QDs and 3D Bi₂WO₆, which contributed to the efficient electron-hole separation and fast transfer of charge carriers between CdS QDs and Bi₂WO₆. A possible Z-scheme photocatalytic mechanism was proposed, in which the sample was provided with the efficient charge transfer pathway and was endowed with excellent oxidation and reduction ability.     

多元醇混合水热法合成MnFe2O4磁性粉体及磁性研究

尺寸小、均匀单分散的MnFe2O4在生物材料、隐身技术、磁流体和锂电池等领域具有巨大的应用潜力.文章采用多元醇混合水热法,以氯化锰(MnCl2·6H2O)、硝酸铁[Fe(NO)3·6H2O]作为原料,以氢氧化钠(NaOH)为矿化剂,TERG作为分散剂,制备出了均匀单分散的MnFe2O4纳米磁性粉体.通过改变反应时间,实现了纳米颗粒的尺寸可控制备.采用XRD、TEM和VSM等手段对制备的纳米磁性材料进行表征.实验结果表明,TREG对MnFe2O4纳米颗粒起到了分散作用,随着MnFe2O4纳米磁性颗粒尺寸的减小,其饱和磁化强度、矫顽力均减小,禁带宽度变大,光吸收能力增强,而且当尺寸为5 nm时,出现特征吸收下降现象.     

氯化钠腌制对鸽肉品质特性的影响

以新疆塔里木肉鸽为原料,设计单因素试验,控制腌制液中氯化钠添加量分别为0%、3%、5%、7%、9%,采用湿法腌制,对腌制后鸽肉的水分含量、水分活度（water activity,aw）、含盐量、硫代巴比妥酸反应物（thiobarbituric acid reactive substances,TBARs）值、挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、pH值等指标进行测定并结合感官评定,探究不同添加量氯化钠腌制对鸽肉品质特性的影响。结果表明：随着氯化钠添加量的增加,鸽肉的水分含量、aw、TBARs值、TVB-N含量、pH值逐渐降低;鸽肉盐含量与氯化钠添加量呈正相关。综合分析各种指标,最终确定腌制液中氯化钠添加量为5%,腌制后的鸽肉表面富有光泽且肉质紧致有弹性,品质较优。     

2-氯-6-三氟甲基吡啶的合成研究

以2-氯-6-三氯甲吡啶为原料,利用三氟化锑反应合成标题化合物。通过MS和NMR分析对产物的结构进行了表征。该合成路线的优点是反应条件温和、无溶剂、收率较高。