冠县灵芝多糖的分离纯化、结构表征及抗氧化活性研究

以冠县灵芝为研究对象,采用传统浸提法获得水溶性灵芝多糖GLP,经Sevag法去蛋白及活性炭脱色,然后依次采用Capto TM DEAE离子柱层析和Superdex 6 prep Grad凝胶柱层析进行分离纯化,获得均一多糖GLPS80a,经高效凝胶色谱(HPGPC)法检测,其相对分子量为9024 Da,高效阴离子色谱(HPAEC)、红外光谱(FT-IR)和核磁共振(NMR)图谱分析结果表明,GLPS80a是由岩藻糖(Fuc)、氨基葡萄糖(GlcN)、半乳糖(Gal)、葡萄糖(Glc)、木糖(Xyl)、甘露糖(Man)和葡萄糖醛酸(GluA)等7种单糖组成,摩尔比为0.06:0.23:0.17:1.00:0.08:0.19:0.23,主要以β-D-(1,6)糖苷键连接的吡喃糖为主要组成且不含三股螺旋的酸性多糖。抗氧化结果表明,GLPS80a具有一定的DPPH自由基、OH自由基和ABTS+自由基的清除能力,它们的EC₅₀分别为7.40、8.74和0.33 mg/mL,还原力RP_0.5AU为8.33 mg/mL。本研究将为合理开发冠县灵芝资源和精深...     

Polyacetylene-based polyelectrolyte as a universal interfacial layer for efficient inverted polymer solar cells

Here we report that poly(N-dodecyl-2-ethynylpyridiniumbromide) (PDEPB) interlayers between electron-collecting zinc oxide (ZnO) layers and bulk heterojunction (BHJ) layers act as a universal interfacial layer for improving the performances of inverted-type polymer:fullerene solar cells. Three different BHJ layers, poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM), poly[(4,8-bis(2-ethylhexyloxy)-benzo[1,2-b:4,5-b']dithiophene)-2,6-diyl-alt-(N-2-ethylhexylthieno[3,4-c]pyrrole-4,6-dione)-2,6-diyl]] (PBDTTPD):PC₆₁BM, and poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7) and [6,6]-phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM), were employed so as to prove the role of the PDEPB interlayers. Results showed that the power conversion efficiency (PCE) of polymer:fullerene solar cells with the three different BHJ layers increased in the presence of the PDEPB interlayers prepared from 0.5 mg/ml solutions. The improved PCE was attributed to the conformal coating of the PDEPB layers on the ZnO layers (by atomic force microscopy measurement), lowered work functions of ZnO induced by the PDEPB layers (by Kelvin probe measurement), and reduced interface resistance (by impedance spectroscopy measurement), as supported by the noticeable change in the atom environments of both the ZnO and PDEPB layers (by X-ray photoelectron spectroscopy measurement).     

Efficient perovskite solar cells using trichlorosilanes as perovskite/PCBM interface modifiers

Interfaces are crucial for high-performance perovskite solar cells. Here, phenyltrichlorosilane (PTS) and octadecyltrichlorosilane (OTS) were used to modify the interface between perovskite layer and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) layer in an inverted layered perovskite device. Such treatments facilitated the formation of a high-quality PCBM film and effectively decreased the density of surface traps that induce undesirable electron-hole recombination. As a result, the average power conversion efficiency of PTS (and OTS) modified devices was improved from 9.60% to 11.96% (and 11.08%), with a highest value of 12.63% (and 11.87%). Therefore, this study provides an attractive mothed to improve the quality of PCBM film on top of perovskite layer and finally the performance of inverted perovskite solar cells.     

Catalytic characteristics of CexCu1-xO1.9 catalysts formed by solid state method for MTS and OMTS reactions

Ce_xCu_1-xO_1.9 (x = 0.3, 0.5, 0.8 and 0.9) catalysts were synthesized by solid state method, using ball mill apparatus, and evaluated in medium temperature shift (MTS), as well as oxygen assisted MTS (OMTS) reactions at temperature range of 300–390 °C. Catalysts were characterized by X-Ray Diffraction (XRD), Temperature Programmed Reduction (TPR), Scanning Electron Microscopy (SEM), and N₂ adsorption-desorption (BET) analysis. Ce_0.9Cu_0.1O_1.9 sample showed the best catalytic activity and structural properties. Decrease in proportion of Cu to Ce, leads to increase in the Cu-Ce mixed oxide formation (according to TPR analysis), significant increase in BET surface area (from 18 m²/g for Ce_0.3Cu_0.7O_1.9–48 m²/g for Ce_0.9Cu_0.1O_1.9), and decrease in CuO crystalline size (XRD). Moreover, the effect of oxygen addition to the feed (O₂/CO ratio = 0, 0.3, 0.5, 0.7 and 1), on the catalytic performance was evaluated. CO conversion was increased by enhancing the amount of oxygen (from 60% to 80% at 360 °C). CO and H₂ oxidations are occurring as competitive parallel reactions in which CO oxidation is dominant at low O₂/CO ratios (<0.5) and H₂ oxidation (undesirable for MTS reaction) at high O₂/CO ratios (>0.5). Furthermore, molar ratios of steam to CO at ranges of 2–4 were compared in OMTS reaction. According to the obtained results, the magnitudes of O₂/CO ratio and S/C ratio which were 0.5 and 4, respectively, were selected as the best values for OMTS reaction.     

地瓜黄浆水与山楂复合发酵饮料的研制

结合农村水果滞销的现状,以黄浆水和滞销的山楂为主要原料,黄浆水经过预处理后添加山楂汁,经调配、均质和乳酸菌发酵技术得到功能饮品。以感官评价为指标,运用单因素实验和响应面分析实验设计优化了功能饮品配方。结果表明,在山楂汁与地瓜黄浆水质量比1:1、糖添加量6%、稳定剂添加量0.5%、乳酸菌接种量1.5%,发酵时间6 h的条件下,产品酸甜适口,口感柔和,具有典型的地瓜香味和山楂清香,组织状态均匀一致、流动性良好,感官评分达到最高(95分)。为黄浆水的资源化利用提供了理论依据,减少环境污染,促进地瓜加工制品产业的全面发展。     

A consideration of grinding limit based on fracture mechanics

In general, it is well known that the energy efficiency of a grinding process decreases with decrease in produced particle size, increase in grinding time, or increase in input energy. In this paper, based on the experimental results of single particle crushing, we define the size reduction energy as the elastic strain energy which is stored in the solids up to the instant of fracture. Assuming that the kinetic energy of a grinding medium was converted completely into fracture energy, the efficiency of size reduction evaluated by the produced specific surface area has been calculated.     

Integration of support vector regression and annealing dynamical learning algorithm for MIMO system identification

This paper presents a robust approach to identify multi-input multi-output (MIMO) systems. Integrating support vector regression (SVR) and annealing dynamical learning algorithm (ADLA), the proposed method is adopted to optimize a radial basis function network (RBFN) for identification of MIMO systems. In the system identification, first, SVR is adopted to determine the number of hidden layer nodes, the initial structure of the RBFN. After initialization, ADLA with nonlinear time-varying learning rate is then applied to train the RBFN. In the ADLA, the determination of the learning rate would be an important work for the trade-off between stability and speed of convergence. A computationally efficient optimization method, particle swarm optimization (PSO) method, is adopted to simultaneously find optimal learning rates. Due to the advantages of SVR and ADLA (SVR-ADLA), the proposed RBFN (SVR-ADLA-RBFN) has good performance for MIMO system identification. Two examples are illustrated to show the feasibility and superiority of the proposed SVR-ADLA-RBFNs for identification of MIMO systems. Simulation results are provided to demonstrate the effectiveness of the proposed algorithm.     

Meat quality and carcass traits in relation to HGD-BstXI and HGD-HaeIII PCR–RFLP polymorphism in Chinese red cattle

We investigated the effect of homogentisate 1, 2 dioxygenase (HGD) gene on meat quality and carcass traits in 287 Chinese red cattle. The PCR–SSCP method was used to identify polymorphism of the HGD gene in the exon 1 and intron 1. Two polymorphisms were detected in intron 1 and two restriction sites for endonuclease HGD-BstXI and HGD-HaeIII have also been found. The HGD-BstXI genotypes showed significant effects on cooking loss, drip loss, net meat weight, carcass weight, and eye muscle area (P < 0.05). The HGD-HaeIII genotypes significant affected cooking loss, muscle fibre diameter, shear force, drip loss, and carcass yield ratio (P < 0.05). Moreover, we found significant effects of diplotypes on cooking loss, muscle fibre diameter, shear force, drip loss, net meat weight, carcass weight, and eye muscle area (P < 0.05).     

A systematic study on the interactions between carnosic acid and ethylpyrrolidine methacrylate–methyl methacrylate copolymer in supercritical media

In the present work, a systematic study on the interactions between carnosic acid (potent natural antioxidant from rosemary) and ethylpyrrolidine methacrylate–methyl methacrylate (EPyM/MMA) copolymer (synthesized in our laboratory) has been performed using different spectroscopic and thermogravimetric techniques. By comparing data obtained for the reference sample (carnosic acid + copolymer) with data of carnosic acid and copolymer alone, a polar interaction could be observed between the carboxylic acid group of carnosic acid with the tertiary amine of the EPyM/MMA copolymer, thus suggesting a charge-transfer complex of the carnosic acid molecules with the pyrrolidine nitrogen (conclusion supported by NMR, FT-IR and TGA data). In order to evaluate the possibility of using, in the near future, the copolymer as a selective stationary phase for preparative-SFC (supercritical fluid chromatography), the work has been completed by studying the remaining interactions, in the reference sample, once treated under several supercritical conditions. After the supercritical treatment (using CO₂ at different pressures and temperatures), depressurization takes place in the extraction cell and the samples remaining were characterized by ¹H NMR, TGA and FT-IR. From the results obtained, it can be inferred that interactions remain after supercritical treatment, thus allowing the design of selective polymers to be used in the purification of carnosic acid.     

Cobalt nanoparticles packaged into nitrogen-doped porous carbon derived from metal-organic framework nanocrystals for hydrogen production by hydrolysis of sodium borohydride

Efficient safe transportation and generation of hydrogen are the key technologies for the hydrogen economy development in future. Sodium borohydride (NaBH₄) features highly volumetric density and environmentally benign hydrolysis products, which making it a promising candidate for chemical hydrogen storage. Cobalt nanoparticles packaged into nitrogen-doped porous carbon were successfully prepared by pyrolysis of MOFs. The addition of Zn in MOFs as a “fence” expanded the distance of adjacent Co atoms in space and simultaneously, the leaving Zn²⁺ sites generated free N sites during pyrolysis. These are beneficial to reduce the sizes of Co nanoparticles and enhance the dispersity of active sites. The modification method allows the cobalt nanoparticles to be uniformly and finely confined within the porous carbon. Contributed by highly dispersed Co nanoparticles and confinement effect, the catalyst showed excellent catalytic activity with hydrogen production rate of 1807 mL (H₂) min⁻¹·g_Co ⁻¹ and lower activation energy (20 kJ/mol) than ever reported. The stability test confirmed that deactivation of catalyst occurred due to deposition of borate species at the surface of catalyst. This observation may provide an idea to modify and upgrade stability of catalyst.