生姜蛋白酶的研究概况

本文介绍了生姜蛋白酶的提取、酶的性质及在食品工业中的应用     

发酵因素对黄原胶分子量的影响

本文报道了发酵因素对黄原胶分子量的影响。研究结果表明,碳源和无机盐是影响黄原胶分子量的极显著因素,而氮源、摇瓶振荡培养速度和接种量则是显著因素。经正交设计统计学分析,产生高分子量黄原胶的摇瓶发酵培养基是:蔗糖2％、玉米粉2％、鱼粉0.3％、豆饼粉0.3％、CaCO_30.3％、pH7.0,摇瓶发酵接种量是1％,摇床振荡培养速度是240rpm。     

基于LSQR与系统距离聚类算法的专变用户非介入式负荷辨识

专变用户非介入式负荷辨识是实现以专变用户为主体的需求侧响应的重要环节。通过对专变用户负荷稳态过程与暂态过程的特征分析,选取有功功率、无功功率、电流有效值等作为稳态过程特征量,并选取暂态发生前、中、后三个阶段的特征量,如电流有效值、有功功率均值、无功功率均值、持续时间、电流有效值最大值等,构建全面的非介入式负荷辨识稳态过程与暂态过程负荷特征空间。以此为基础,利用最小二乘QR分解算法(Least Square QR,LSQR)进行稳态过程负荷分解获得各种负荷的运行情况。并基于系统距离聚类算法将常见专变用户负荷暂态事件进行分类,进一步辨识出哪一种或者哪一类负荷发生投切动作。最后,采集包括排水泵、搅拌机、水泥螺旋、污水泵、除尘器等工业负荷现场数据,对所提到的方法进行了仿真分析,结果表明所提的非介入式负荷辨识方法可获得较高的准确率。     

Optical and electrical properties of porous silicon layer formed on the textured surface by electrochemical etching

Porous silicon (PS) layers were formed on textured crystalline silicon by electrochemical etching in HF-based electrolyte. Optical and electrical properties of the TMAH textured surfaces with PS formation are studied. Moreover, the influences of the initial structures and the anodizing time on the optical and electrical properties of the surfaces after PS formation are investigated. The results show that the TMAH textured surfaces with PS formation present a dramatic decrease of reflectance. The longer is the anodizing time, the lower is the reflectance. Moreover, an initial surface with bigger pyramids achieved lower reflectance in short wavelength range. A minimum reflectance of 3.86 % at 460 nm is achieved for a short anodizing time of 2 min. Furthermore, the reflectance spectrum of the sample, which was etched in 3 vol.% TMAH for 25 min and then anodized for 20 min, is extremely flat and lies between 3.67% and 6.15% in the wavelength range from 400 to 1040 nm. In addition, for a short anodizing time, a slight increase in the effective carrier lifetime is observed. Our results indicate that PS layers formed on a TMAH textured surface for a short anodization treatment can be used as both broadband antireflection coatings and passivation layers for the application in solar cells.     

1-甲基-4,5-二硝基咪唑的工艺优化及热分解动力学研究

以甲基咪唑为原料,采用一步硝化法合成1 -甲基-4,5-二硝基咪唑,并通过元素分析、红外光谱以及核磁共振光谱、质谱对其结构进行了表征.通过正交试验考察了反应温度、反应时间及反应物物质的量比对产率的影响,得出最佳工艺条件为:反应温度80～85℃,反应时间2h,发烟硝酸与发烟硫酸的物质的量比1:2.在此条件下产品收率为74...     

胡尖山油田三叠系延长组长21储层特征及控制因素

通过扫描电镜、铸体薄片、岩心和测井等相关资料分析,对鄂尔多斯盆地胡尖山油田三叠系延长组长2,砂岩储层特征进行研究。研究表明,储层砂岩主要为细一中粒长石砂岩和岩屑长石砂岩,分选较好,磨圆度以次棱状为主,填隙物以高岭石为主。储层物性较差,孔隙类型主要为粒间孔和长石溶孔,并发育少量的晶间孔及岩屑溶孔,属于低一中孔、低一特低渗...     

S Zorb装置汽油脱硫过程中吸附剂失活原因分析

针对S Zorb装置运行过程中出现的吸附剂失活快、剂耗高等问题,采用SEM、XRD、XRF、XPS、MAS-NMR等多种表征手段对不同形态吸附剂的物化性质进行系统的表征研究。结果表明：S Zorb装置运行过程中锌铝尖晶石和硅锌矿等非活性含锌物相的形成会导致吸附剂中有效ZnO含量的大幅降低,当ZnO的量降低到不足以完成吸附硫的转移时,工艺上即表现为吸附剂的失活和脱硫效率的降低。锌铝尖晶石的形成将导致吸附剂的强度下降,使吸附剂颗粒更易破碎,增加剂耗。在S Zorb装置运行过程中,对待生剂和再生剂物相组成变化的跟踪监测有助于保障装置的平稳运行,保持良好的脱硫效率。     

The role of nanopore shape in surface-induced crystallization

Crystallization of a molecular liquid from solution often initiates at solid-liquid interfaces, and nucleation rates are generally believed to be enhanced by surface roughness. Here we show that, on a rough surface, the shape of surface nanopores can also alter nucleation kinetics. Using lithographic methods, we patterned polymer films with nanopores of various shapes and found that spherical nanopores 15-120 nm in diameter hindered nucleation of aspirin crystals, whereas angular nanopores of the same size promoted it. We also show that favourable surface-solute interactions are required for angular nanopores to promote nucleation, and propose that pore shape affects nucleation kinetics through the alteration of the orientational order of the crystallizing molecule near the angles of the pores. Our findings have clear technological implications, for instance in the control of pharmaceutical polymorphism and in the design of 'seed' particles for the regulation of crystallization of fine chemicals.     

The influences of particle sizes on the dielectric properties of PEI/(Ba0.8Sr0.2)(Ti0.9Zr0.1)O3 composites

In order to investigate the embedded capacitors with higher capacitance value in the future, two technologies of increasing the dielectric constant of filler and decreasing the thickness of capacitors can be combined to develop a best method. For that, the high dielectric constant of (Ba0.8Sr0.2)(Ti0.9Zr0.1)O3 (BSTZ) ceramic powders with three different sizes (3 microm, 200 nm, and 100 nm) are used as the filler to mix with polyetherimide (PEI) to form the PEI/BSTZ composites. The dielectric constants and loss tangents of PEI/BSTZ composites with different contents of BSTZ ceramic powders are measured using the plate method. As the contents of BSTZ powders increase from 10 wt% to 70 wt%, the dielectric constants and loss tangents of PEI/BSTZ composites increase with the increase content of BSTZ ceramic powders, independent on the particle sizes. As the BSTZ content is less than and equal to 50 wt% and same loading ratio is used, the dielectric constants of PEI/200 nm-BSTZ and PEI/100 nm-BSTZ composites are large than those of PEI/3 microm-BSTZ composites. In this study, the Lichtenecker logarithmic mixing rule is also used to fit the measured results and predict the dielectric constants of PEI/BSTZ composites.     

Charge transfer directed growth and morphology regulation of silver nanoparticles

We demonstrate the control of silver nanoparticle growth in electroless deposition by utilizing surfaces of varying conductivity. Nanoscopic wires can be developed on non-conductive substrates, whereas nanoloops and microspheres are produced on surfaces of weak and high conductivity, respectively. Our observations reveal that the morphologies of electroless deposition can be regulated by the charge transfer through substrates, which indicates the important role of a redox reaction potential and a size-dependent chemical potential as the driving force behind this directed growth.