米酒老面添加量对面团及馒头品质的影响

本文研究了米酒老面添加量(40%、50%、60%、70%和80%)对面团的pH、湿面筋含量、面筋指数及馒头的比容、硬度、白度、感官评分的影响。结果表明:随着米酒老面添加量的增加,面团pH呈现下降的趋势。米酒老面添加量为60%的面团中湿面筋含量显著低于其他四种添加量(P<0.05),馒头的比容、硬度、白度和感官评分显著高于其他四种添加量(P<0.05)。相关性分析表明,面团pH与馒头的感官评分呈极显著负相关(P<0.01);面团湿面筋含量与馒头比容呈显著负相关(P<0.05),与馒头硬度呈显著正相关(P<0.05),与馒头白度呈极显著负相关(P<0.01)。面团面筋指数与馒头比容呈极显著正相关(P<0.01),与馒头硬度呈极显著负相关(P<0.01),与馒头白度呈显著正相关(P<0.05)。米酒老面的添加会改变面团和馒头的品质,其最适添加量为60%。     

响应面法优化自发馒头粉配方

以成品馒头白度、硬度及感官评分为评价指标，在单因素试验的基础上，采用Box-Behnken试验设计对自发馒头粉配方中的酵子、酵母、化学膨松剂（碳酸氢钠和葡萄糖酸内酯）添加量3个因素进行优化，确定适宜的自发馒头粉配方。结果表明，最优的自发馒头粉配方为：酵子添加量0.86%、酵母添加量0.5%、化学膨松剂添加量1.2%（NaHCO3∶葡萄糖酸内酯=42∶89），采用最优自发馒头粉蒸制的馒头的白度为53.4，硬度为452 g，感官评分为87.5分。     

耐腐蚀水性铝颜料的制备及表征

为了提高铝颜料在水性涂料中的耐腐蚀性能，以正硅酸乙酯（ TEOS）为前驱物，通过溶胶-凝胶反应在铝颜料表面形成了一层致密的二氧化硅包覆薄膜，通过优化固含量、溶剂种类及 TEOS的用量，提高铝颜料的耐碱性。利用扫描电镜、刮板试验、接触角测试、析氢实验进行表征，结果表明：以无水乙醇为溶剂，铝金属颜料固含量为 10%，升温至 50 ℃后，逐滴加入 6 g TEOS，再升温至 80 ℃，该条件下制备的 SiO₂膜包覆后的铝颜料具有优异的耐碱性，同时表面性能由疏水性转变成亲水性，对铝颜料起到了很好的保护作用。     

基于氮掺杂碳纳米颗粒荧光猝灭-恢复方法检测还原型谷胱甘肽

分别以海藻酸钠和色氨酸为碳源和氮源,采用固相法一步合成出了量子产率为47.9%的氮掺杂荧光碳纳米颗粒(N-CNPs)。根据铜离子存在的条件下,N-CNPs荧光强度的恢复情况与还原型谷胱甘肽浓度成正比的关系,建立基于N-CNPs检测还原型谷胱甘肽的新方法。优化了溶液pH及反应时间等条件。在pH 6.0、铜离子浓度30μmol/L条件下,谷胱甘肽在0.2~45μmol/L浓度范围内与N-CNPs荧光恢复强度呈良好的线性关系,检出限为50 nmol/L。方法具有灵敏度高、选择性好、操作简单等优点,可用于实际样品中谷胱甘肽的检测。     

Assessing the width of Gaussian density of states in organic semiconductors

The Density of States (DOS) is an ingredient of critical importance for the accurate physical understanding of the optoelectronic properties of organic semiconductors. The disordered nature of this class of materials, though, renders the task of determining the DOS far from trivial. Its extraction from experimental measurements is often performed by driving the semiconductor out of thermal equilibrium and therefore requires making assumptions on the charge transport properties of the material under examination. This entanglement of DOS and charge transport models is unfavorable since transport mechanisms in organic semiconductors are themselves still subject of debate. To avoid this, we propose an alternative approach which is based on populating and probing the DOS by means of capacitive coupling in Metal Insulator Semiconductors (MIS) structures while keeping the semiconductor in thermal equilibrium. Assuming a Gaussian shape, we extract the DOS width by numerical fitting of experimental Capacitance–Voltage curves, exploiting the fact that the DOS width affects the spatial distribution of accumulated charge carriers which in turn concurs to define the MIS capacitance. The proposed approach is successfully tested on two benchmark semiconducting polymers, one of n-type and one of p-type and it is validated by verifying the robustness of the extraction procedure with respect to varying the insulator electrical permittivity. Finally, as an example of the usefulness and effectiveness of our approach, we study the static characteristics of thin film transistors based on the aforementioned polymers in the framework of the Extended Gaussian Disorder transport model. Thanks to the extracted DOS widths, the functional dependence of current on the gate voltage is nicely predicted and physical insight on transistor operation is achieved.     

Tuning lattice strain in biphenylene for enhanced electrocatalytic oxygen reduction reaction in proton exchange membrane fuel cells

As proton-exchange membrane fuel cell technology has grown and developed, there has been increasing demand for the design of novel catalyst architectures to achieve high power density and realize wide commercialization. Herein, based on the two-dimensional biphenylene, we compare the oxygen reduction reaction (ORR) activity on the active sites with different biaxial lattice strains using first-principles calculations. The ORR free energy diagrams of biphenylene monolayers with varying lattice strains suggest that the biaxial tensile strains are unfavorable for catalytic activity. In contrast, the biaxial compressive strains could improve the catalytic performance. The biphenylene systems with the strain of ?2% ～ ?6% (S_{-0.02～-0.06}) display overpotentials of 0.37–0.49 V. This performance is comparable to or better than the Pt (111) surface. The Bader charge transfer of adsorbed O species on various biaxial strain biphenylene catalysts could be a describer to examine the catalytic activity. The catalysts possessed the moderate transferred charge of O adsorbed species often promotes catalytic process and give the high catalysis efficiency. Overall, this work suggests that the lattice strain strategy can significantly enhance the catalytic activity of biphenylene materials and further provide guidance to design biphenylene-based catalysts in various chemical reactions.     

某热镀锌车间腐蚀后鉴定分析与加固措施

通过对于某腐蚀环境下钢筋混凝土工业厂房的现场测试和构件受力性能的分析研究对构件的安全性能作出了合理的评价,提出了保证正常施工情况下结构的维修加固方案。     

基于复局部均值分解和复信号包络谱的滚动轴承故障诊断方法

提出了一种基于复局部均值分解(CLMD)和复信号包络谱(CSES)的滚动轴承故障诊断新方法。首先通过互相垂直安装的加速度传感器采集2个方向的振动信号,并将其组成一个复数信号;然后利用CLMD对二元复数信号进行自适应分解,将分解得到的复数信号的实部和虚部包络信号组成一个复包络信号,根据复傅里叶变换具有幅值增强和综合频率特性,直接对复包络信号进行复傅里叶变换,提取的故障特征频率更为清晰。通过滚动轴承不同位置的外圈故障实验,证明了所提方法能够实现故障特征增强,可用于诊断滚动轴承微弱故障和复合故障。     

Searching proper oligothiophene segment as centre donor moiety for isoindigo-based small molecular photovoltaic materials

Systematic studies on a family of photovoltaic molecules are important for fundamentally understanding the basic principles and the key structural factors that govern their photovoltaic performance. In this work, a series of D²-A-D¹-A-D² type small molecules with isoindigo as acceptor (A), oligothiophene as donor (D¹), and 5-hexyl thiophene as D² were designed, synthesized and studied. The number of thiophene unit in oligothiophene segment is systematically varied from 0 to 4. It has been found this structural parameter have significant influence on their phase transition behaviours, light absorption properties, frontier orbital energy levels, molecular packing structures in both neat and blending films with [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM), charge mobility, phase separation morphology, and as well as photovoltaic performances. The compounds bearing odd number of thiophene unit displayed much better photovoltaic performance than those having even number, while the best performance was given by that having terthiophene as D¹ unit.     

Facial synthesis of dandelion-like g-C3N4/Ag with high performance of photocatalytic hydrogen production

Nowadays, energy shortage is one of the major problems in the world. Photocatalytic hydrogen production is a new type of energy technology with good application prospect. As a new type of photocatalytic semiconductor material, g-C₃N₄ has attracted much attention as a photocatalyst. By ultrasonic treatment of a mixed solution of g-C₃N₄ and bovine serum albumin, followed by adding a certain amount of silver nitrate solution and then directly hydrothermal treatment, a special dandelion-like g-C₃N₄/Ag (D-g-C₃N₄/Ag) was prepared. The scanning electronic microscopy, transmission electronic microscopy, X-ray diffraction, Fourier transform infrared, fluorescence and physicochemical adsorption methods were used to characterize the morphology and structure of D-g-C₃N₄/Ag. In addition, the photocatalytic H₂ production of D-g-C₃N₄/Ag with different Ag loadings or in different sacrificial agents and different pH conditions were investigated. The results indicated that when triethanolamine was used as sacrificial agent, photocatalytic hydrogen efficiency was the best, and the rate of photocatalytic hydrogen production reached 862 μmol g⁻¹ h^{− 1} as the Ag loading was 4%.