小麦淀粉清液生料发酵酒精工艺的研究

对小麦淀粉清液生料发酵酒精工艺中的关键问题进行研究,结果表明,采用超级酿酒高活性干酵母菌种,小麦淀粉清液浓度为22%,每200mL清液中添加0.18g糖化酶,35℃发酵,小麦淀粉生料发酵的酒精度较高、残余淀粉量少,并可有效改善传统蒸煮发酵引起的粘度高过滤困难等问题。     

微量元素富集的研究进展

阐述了几种微量元素的生理功能及它们的功能性应用进展,重点介绍了富集微量元素的主要方法和国内外研究情况,同时从遗传学角度对矿物质元素的富集进行了展望,提出了应从多学科、多领域、多角度对人体营养与健康进行研究的建议。     

基于PLC的新型皮革转鼓自动控制系统

针对一种新型皮革转鼓,采用西门子S7-200PLC设计了一套自动控制系统,使该型转鼓的工作实现了自动化。该自动系统具有手动、自动和回原点三种工作方式,配合触摸屏使得系统的操作具有很大的灵活性和方便性。     

铬在土壤和植物中的吸附、迁移和累积规律研究进展

介绍了农用制革污泥中的铬在土壤环境中的迁移转化积累,分析了植物对铬的吸收和积累规律,并探索了铬在植物生长发育中的作用和对土壤—植物系统的影响,为制革厂污泥农用提供一定的理论依据。     

Synthesis and electrochemical performance of three-dimensional ordered hierarchically porous Li4Ti5O12 for high performance lithium ion Batteries

In this work, a three-dimensional ordered hierarchically porous (3DOHP) Li₄Ti₅O₁₂ that possesses inner-particle mesopores resulting from a soft template method and a three-dimensional ordered macroporous (3DOM) Li₄Ti₅O₁₂ using polystyrene spheres as a hard template have been synthesized. Both 3DOM Li₄Ti₅O₁₂ and 3DOHP Li₄Ti₅O₁₂ have ordered macropores and interconnected skeletons with a regular periodicity revealed by SEM and TEM observations. The specific surface area of 3DOHP Li₄Ti₅O₁₂ is up to 135 m² g^?1 which is much higher compared with that of 3DOM Li₄Ti₅O₁₂ because of the existence of inner-particle mesopores. Attributed to the higher surface area and smaller crystal grain size, more excellent cycle performance and rate capability are obtained for 3DOHP Li₄Ti₅O₁₂ compared to 3DOM Li₄Ti₅O₁₂. In addition, the hierarchically porous structure of 3DOHP Li₄Ti₅O₁₂ can meet rapid insertion and deinsertion of lithium ion even at extremely high rate. It is apparent that 3DOHP Li₄Ti₅O₁₂ has a lower total resistance and faster Li⁺ diffusion coefficient compared to 3DOM Li₄Ti₅O₁₂ according to electrochemical impendence spectroscopy analysis.     

Enhanced energy storage properties of Ba0.4Sr0.6TiO3 lead-free ceramics with Bi2O3-B2O3-SiO2 glass addition

In this study, we present an effective strategy to enhance the energy storage properties of Ba_0.4Sr_0.6TiO₃ (BST) lead-free ceramics by the addition of Bi₂O₃-B₂O₃-SiO₂ (BBS) glass, which were prepared by the conventional solid state sintering method. The phase structure, microstructure and energy storage properties were investigated in detail. It can be found that the Ba_0.4Sr_0.6TiO₃-x wt%(Bi₂O₃-B₂O₃-SiO₂) (BST- x wt%BBS, 0 ≤ x ≤ 12) ceramics possess large maximum polarization (P_max), low remanent polarization (P_r) and slim polarization electric field (P-E) hysteresis loops. The breakdown strength (BDS), recoverable energy storage density (W_rec) and energy storage efficiency (η) are enhanced obviously with the addition of BBS glass. The BST-9 wt%BBS ceramic is found to exhibit excellent energy storage properties with a W_rec of 1.98 J/cm³ and a η of 90.57% at 279 kV/cm. These results indicate that the BST-x wt%BBS ceramics might be good candidates for high energy storage applications.     

基于功频下垂控制的光伏并网发电系统惯量阻尼机理研究

针对光伏以低惯量、弱阻尼的特征大规模接入电网，给电网稳定性带来不利影响的问题，基于功频下垂控制的光伏并网发电系统，借鉴经典电气转矩分析法，从物理机制层面上分析影响系统惯量、阻尼以及同步能力的作用规律。研究结果表明对于控制参数的影响规律而言，惯量特性主要受功率环的比例系数Kp影响，且随Kp的增大而增强；阻尼特性受频率下垂系数Dp影响比较明显，且随Dp的增大而减弱；同步特性只受功率环的比例积分系数Ki影响，且随Ki的增大而增强。通过仿真验证了理论分析的正确性。     

SnO2 modified PNN-PZT ceramics with ultra-high piezoelectric and dielectric properties

In this work, a two-step solid-state reaction method is used to prepare the 0.55 Pb(Ni_1/3Nb_2/3)O₃-0.135PbZrO₃-0.315PbTiO₃/xSnO₂ (PNN-PZT/xSnO₂) ceramics. The influences of SnO₂ on the crystalline structure, electromechanical properties, and temperature stability of PNN-PZT ceramics were studied in detail. The results demonstrate that the Sn⁴⁺ ions are successfully introduced into the PNN-PZT crystalline lattice and substitute B-site Ni²⁺ and Zr⁴⁺. The x = 0.0025 ceramic with the coexistence of rhombohedral, tetragonal, and pseudocubic phases exhibits the optimized comprehensive properties: the quasi-static piezoelectric constant d₃₃, large-signal d₃₃*, electromechanical coupling coefficients k_p and k_t, free dielectric constant ε_r, and mechanical quality factor Q_m are 1123 pC/N, 1250 p.m./V, 0.63, 0.54, 9529, and 57, respectively. Meanwhile, the Curie temperature for this composition is 103 °C, almost maintaining the same level as the PNN-PZT matrix. After annealing at 75 °C, the retained d₃₃ of x = 0.0025 ceramic is as high as 975 pC/N, superior to the PNN-PZT matrix (retained d₃₃ ≈ 873 pC/N). Our results provide a promising piezoelectric material for board bandwidth, high sensitivity, and miniaturized medical ultrasonic transducers applications.