Modeling of Calcium Chloride and Pectin Methylesterase Prefreezing Treatments of Strawberries and Jams

ABSTRACT: :
Different calcium chloride (CaCl₂) and pectin methylesterase (PME) prefreezing treatments in a vacuum were used to clarify the most effective prefreezing factors for strawberries and traditional jams. Fractional factorial design and modeling were used. CaCl₂ had the greatest effect on the majority of the 15 studied responses ( p < 0.001). The pretreatment time should be short (about 5 to 10 min), the temperature low (less than 20 °C), the vacuum level high (pressure less than 10 kPa), the CaCl₂ concentration moderate (about 1%) and the dosage of PME comparatively low (about 50 to 100 nkat/g) in order to yield high quality frozen strawberries for jam making.     

BaFe12O19/SiO2-B2O3微晶玻璃陶瓷的制备和微波性能

采用柠檬酸sol-gel工艺合成了BaFe12O19/SiO2-B2O3微晶玻璃陶瓷，研究了SiO2-B2O3玻璃的含量，Ba/Fe原子比和热处理温度对体系析出晶相的影响，以及介电常数和磁异率在1MHz-6GHz频率范围的变化规律，结果表明，休系中SiO2-B2O3玻璃的含量和Ba/Fe比越高，BaF312O19相的析出越困难，前驱体合适的热处理温度为1000℃，介电常数和磁导率基本上随测试频率的增而加下降；介电损耗的最大值为0．43，磁损耗较小。     

Cif2000平台下的核磁共振测井解谱方法研究

介绍了在Cif2000多井解释平台下的核磁共振解谱方法与编程实现。解谱采用加入平滑因子后在特征矩阵的奇异值分解中截去小的非零奇异值的方法，可以在低信噪比时得到稳定的弛豫谱，在油田实际应用中证明了该方法的有效性。根据该方法在Cif2000平台上编制了完整的解谱处理程序，可以直接用于油田的生产实际。     

ZnGa2O4纳米晶的制备和结构表征

采用喷射共沉淀法制备了ZnGa2O4 纳米晶，XRD、SEM和TEM结构分析结果表明，喷射共沉淀法制备的ZnGa2O4的纳米晶颗粒细小均匀，形状完整，与化学共沉淀法相比，粒子尺寸明显减小，小于10nm，同时ZnO杂相峰消失，分析了喷射共沉淀法的机理，并对实验结果进行了解释。     

Synthesis, Characterization, and Formation Process of Na-X Zeolite from Coal Fly Ash

Using the SiO₂ and Al₂O₃ components of the amorphous phase in coal fly ash (Fa), Fa was converted to Na-X zeolites in NaOH-NaAlO₂ solutions by stirring at 35°C for 72 hr and then aging at 85°C for a given period. The molar ratio SiO₂/Al₂O₃ of the starting materials was controlled from 2.0 to 13.2. The resulting materials were characterized by various means. Increasing the SiO₂/Al₂O₃ ratio of the starting material increased the degree of crystallinity of faujasite, exhibiting a maximum at SiO₂/Al₂O₃ = 8.0. The faujasite formed was identified as Na-X zeolite with Si/Al = 1.20. The amorphous phase in Fa was dissolved during the stirring to form a precursor of zeolite, such as amorphous aluminosilicate. The Na-X zeolite was formed by aging for 24 hr, and the degree of crystallinity of this material was increased with the increasing aging period. The cation exchange capacity and specific surface area were increased with the increasing degree of crystallinity of the Na-X zeolites.     

无线智能网技术

本介绍CDMA无线智能网（WIN）的产生背景、技术标准、提供的业务、与GSM移动智能网技术上的差异以及它在实际工程中的应用，最后对WIN的发展进行展望。     

Preparation and Application of Active Composite Antibacterial Material Containing Ag~ and Zn~(2 )

1Introduction Harmfulbacteriaexistanywhereintheworldsuchas soil,air,water,surfacesofobjectsandourskins,etc.Thenumberofbacteriumisenormous,withmanydiffer entspecies.Theyhavethreatenedthehealthofhuman beingsseriously.Withthedevelopmentofeconomyand environme…     

燃烧—气体容量法测定冶金石灰中的二氧化碳

冶金石灰是石灰石经过工业煅烧的产品。其二氧化碳含量低，且经过高温煅烧后基本不含有机物。无需按照《石灰石、白云石化学分析国家标准中二氧化碳的化学分析方法》中用酸进行试样分解，只需在1200℃高温中灼烧，使石灰中残留的或煅烧后吸收空气中二氧化碳而形成的碳酸盐分解，象通常测定含碳耐火材料中二氧化碳那样，采用气体容量法进行测定。     

MoSi2发热体在熔铝炉中的运用

以电阻熔铝炉技术改造实践为例，介绍一种高效、节能、不渗铁的新型熔铝炉——二硅化钼熔铝炉的设计。     

用环境友好催化剂合成丙酸异丁酯的研究

报道了以固载杂多酸盐TiSiW12O40/TiO2为环境友好催化剂，对以丙酸和异丁醇为原料合成丙酸异丁酯的反应条件进行了研究。实验表明：TiSiW12O40/TiO2是合成丙酸异丁酯的良好催化剂，最佳反应条件为：n（醇）：n(酸）=1.2:1，催化剂用量为反应物料总质量的2.0%。反应时间1.0h，反应温度106-125℃，上述条件下，丙酸异丁酯的收率可达79.1%。