Optimal adaptive control schemes for PHB production in fed-batch fermentation of Ralstonia eutropha

A dynamic model for a fed-batch fermentation of Ralstonia eutropha for PHB production is presented. Based on the simplified kinetics, some of kinetic parameters are very sensitive to uncertainties. To develop the robust and feasible feeding strategy, the specific optimal adaptive control strategy is determined by solving the constrained discrete-time optimization algorithm using the genetic algorithm solver in Matlab. The proposed control methods are implemented to the feed flow manipulation with stepwise changes. Through Lyapunov stability analysis, the closed-loop stability regarding the state estimation errors and parametric uncertainties is investigated. Finally, simulations show that the satisfactory output tracking performance is achieved under the two-input control configuration.     

Glass microparticle- versus microsphere-filled experimental dental adhesives

This study aimed to formulate antibacterial dental adhesives. Phosphate-substituted methacrylate adhesives were modified with 0–20 wt % copper-doped glass microparticles. Two shapes of microparticles were used: regular shaped (microspheres) and irregular shaped (microparticles). The morphology/composition, roughness, monomer conversion (DC%), thermogravimetric analysis, and antibacterial action against S. mutans and P. aeruginosa and ion release were investigated. The results showed that microspheres produced adhesives with a relatively smoother surface than microparticles did. The DC% of adhesives increased with increasing glass filler content. Filled adhesives showed polymer decomposition at ~315 °C and glass melting at 600–1000 °C. The weight loss percent of adhesives decreased with increasing weight percent of fillers. Glass microparticles at 0–20 wt % significantly increased the antibacterial action of adhesives against both bacteria. Glass microspheres at 0–5 wt % significantly increased the antibacterial action of adhesives against both bacteria. Only 20 wt % microparticle-filled adhesive showed an inhibition zone similar to tobramycin (positive control). Microparticle-filled adhesives (with >5 wt % filler) significantly reduced S. mutans more than their microsphere counterparts. Microsphere-filled adhesives (with ≤5 wt % filler) significantly reduced P. aeruginosa more than their microparticle counterparts. Microsphere-filled adhesives showed higher Cu release than their microparticle counterparts. Accordingly, phosphate-substituted methacrylate filled with glass could be used as an antibacterial adhesive. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47832.     

矿山充填自动化控制技术的研究与应用

尾矿充填能够减少尾矿对地表的污染及提高对矿石的回采率,但高质量的尾矿胶结充填对工艺控制要求严格,人工难以操作完成。为切实解决尾矿充填中存在的控制问题,保障尾矿充填的质量,根据我国尾矿充填的工艺特点及现有条件对尾矿充填的控制技术进行了研究,并将研究技术多次运用于对尾矿充填的控制实现,从而获得了良好的控制效果,为相关应用提供了宝贵的借鉴经验。     

Reductive crystallization of each metal in composite particles spray-pyrolyzed from silver/nickel mixed nitrates

Composite particles prepared by spray pyrolysis of aqueous solution of AgNO₃ and Ni(NO₃)₂·6H₂O with 10 vol%H₂-N₂ were characterized and compared with the particles similarly prepared from their pure nitrates. The composite particles were composed of metallic silver, nickel oxide or metallic nickel, depending on the condition, with no trace of alloy. The existence of nickel ions dispersed throughout the particles did not affect the rate of reduction to the highly reducible silver but retarded its subsequent crystal growth. On the other hand, both the reduction to nickel and its crystal growth were all retarded due to the existence of the more reducible silver ions. In addition to these, the incompatibility also increased the size of the composite particles from the corresponding single component particles and kept it almost constant with respect to the preparation temperature.     

基于高压脉冲电场技术提高松子肽的抗氧化活性研究

目的为了初步揭示高压脉冲电场(PEF)技术提高分子量小于1 kDa松子肽的抗氧化活性的作用机制。方法以DPPH自由基清除能力为衡量指标,利用单因素和响应面试验设计研究方法,构建出基于PEF技术提高分子量小于1 kDa松子肽的抗氧化活性回归模型,优化出最佳技术参数,并借助傅立叶红外光谱技术分析其官能团变化情况。结果回归模型为:Y=84.4+0.31X_1+0.6X_2+1.13X_3-0.26X_1X_2-0.062X_1X_3-0.79X_2X_3-3.32X_1~2-5.21X_2~2-3.37X_3~2,最佳技术参数为电场场强12.6 kV/cm、电场频率1616 Hz、物料流速3.456 mL/min,其DPPH自由基清除能力为83.5 1%±0.61%,与未经高压脉冲电场处理松子肽相比,增加了26.69%;借助傅立叶红外光谱技术分析发现,分子量小于1 kDa松子肽经PEF处理后的-C≡N键发生变化。结论高压脉冲电场技术可以提高松子肽的抗氧化活性,通过傅立叶红外光谱技术可知抗氧化活性的提高可能是由于松子肽的-C≡N键发生变化。     

On the leading leg transition of phase-shifted ZVS-FB converters

The primary current drop during the leading leg transition of phase-shifted zero-voltage-switching full-bridge (ZVS-FB) power converters is investigated. It is shown that this phenomenon is affected by the junction capacitance of rectifier diodes and transformer winding capacitance     

Quality characteristics of gochujang meju prepared with different fermentation tools and inoculation time of Aspergillus oryzae

To standardize a preparation method for traditional gochujang, 4 types of meju were prepared using different fermentation tools and inoculation time of Aspergillus oryzae with Bacillus subtilis. The acidic protease activities of the S-1 and S-2 were higher and significantly different than those of S-3 and S-4 on 8-day fermentation at 30°C. The free amino acid contents of the meju were high, in the order of S-2 (275.9 mg%, w/w) > S-1 (238.3 mg%) > S-3 (215.0 mg%) > S-4 (189.9 mg%). The amino-type nitrogen contents of the S-1 (355.6±12.3 unit/mL) and S-2 (327.0±5.8 unit/mL) were higher and significantly different than those of S-3 and S-4 on 4-day fermentation. However, no consistent differences were observed between S-1 and S-2 during the fermentation period. Therefore, we conclude that meju fermentation was largely affected by the inoculation time of A. oryzae rather than the fermentation tool (tray or net).     

Effect of pore size on the high temperature oxidation of Ni-Fe-Cr-Al porous metal

This study investigated the effect of the pore size of Ni-22.4%Fe-22%Cr-6%Al porous metal on its hightemperature oxidation. Two types of open porous metals with pore sizes of 800 μm and 580 μm were used. A 24-hour isothermal oxidation test was conducted at three different temperatures of 900 °C, 1000 °C, and 1100 °C under a 79% N₂ + 21% O₂ atmosphere. The results of the BET analysis revealed that the specific surface area increased as the pore size decreased from 800 μm to 580 μm. The high-temperature oxidation results showed that porous metals exhibited far lower levels of oxidation resistance compared with bulk metals, and that the oxidation resistance of porous metals decreased with a decreasing pore size. According to the microstructural observations of the oxide layers, the 900 °C and 1000 °C oxidation layer contained Ni, Cr, and Al oxides mainly on the strut. The 800 μm porous metal strut exhibited similar oxidation behavior at 1100 °C to that found at lower temperatures. In contrast, the 580 μm porous metal strut was found to consist of Ni and Fe oxides in the upper layer and Ni, Cr, and Al oxides in the lower layer, representing a low oxidation resistance. For powders affixed to the strut inside the porous metal, a different oxide-forming behavior from that of the strut was observed. In addition, the Ni-Fe-Cr-Al porous metal high-temperature oxidation microscopic mechanism is also discussed.     

一种新的灰度图像Legendre矩的快速算法

Legendre正交矩在模式识别和图像分析等领域有着广泛的应用，但由于计算的复杂性，相关的快速算法尚未得到很好的解决，已有方法均局限于二值图像．文章提出了一种灰度图像的Legendre正交矩的快速算法，借助于Legendre多项式的递推公式推导出计算一维Legendre矩的递归公式．利用该关系式，一维Legendre矩Lp可以用一系列初始值L1(a)，a＜p，Lo(a)，a＜p-1来得到．而二维Legendre矩pq可以利用一维算法进行计算,为了降低算法复杂度，文中采用基于Systolic阵列的快速算法进行计算L1(a)，Lo(a),与直接方法相比，快速算法可以大幅度减少乘法的次数，从而达到了降低算法复杂度的目的。     

松茸多肽对东莨菪碱致记忆损伤小鼠的改善作用

目的 探究两条松茸多肽(SFPPIWQ和SHSFFLP)对东莨菪碱致记忆损伤小鼠的改善作用。方法 将80只昆明小鼠随机分为正常组、模型组、SFPPIWQ低、中、高剂量组及SHSFFLP低、中、高剂量组,采用腹腔注射东莨菪碱构建记忆损伤小鼠模型,进行小鼠体成分测定和体成像,实验期间每周1次水迷宫行为学实验,测定血液中谷丙转氨酶(alanine transaminase,ALT)、谷草转氨酶(aspartate,AST)、超氧化物歧化酶(superoxide dismutase, SOD)、脂质过氧化物(malondialdehyde, MDA)水平,测定海马中乙酰胆碱(acetyl choline,Ach)、乙酰胆碱酯酶(acetylcholin esterase,AchE)水平,尼氏染色观察小鼠海马组织。结果 各组小鼠体成分无显著差异。水迷宫行为学结果显示,与模型组相比, SFPPIWQ和SHSFFLP组逃逸潜伏期降低。各组小鼠血清ALT和AST水平无显著差异;与模型组相比, SFPPIWQ和SHSFFLP组血清中SOD活性升高、MDA水平降低,海马中Ach含量升高、AchE活性降低。...