Examination of Subunit Composition of Bombyx Mori Silk Fibroin

Main subunits of the silk fibroin were separated by GFC(gel filtration chromatography)technigue.The nativesilk fibroin and α,c subunits were measured by gel elec-trophoresis.The aminoacid compositions of the nativesilk fibroin and α,c subunits were analyzed by means ofaminoacid measurement.Some properties of silk was inter-preted in view of subunit composition of silk fibroin.     

Effects of MgO and TiO<Subscript>2</Subscript> on the viscous behaviors and phase compositions of titanium-bearing slag

The effects of MgO and TiO₂ on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed by Fourier transform infrared (FTIR) spectroscopy. Subsequently, main phases in the slag and their content changes were investigated by X-ray diffraction and Factsage 6.4 software package. The results show that the viscosity decreases when the MgO content increases from 10.00wt% to 14.00wt%. Moreover, the break-point temperature increases, and the activation energy for viscous flow initially increases and subsequently decreases. In addition, with increasing TiO₂ content from 5.00wt% to 9.00wt%, the viscosity decreases, and the break-point temperature and activation energy for viscous flow initially decrease and subsequently increase. FTIR analyses reveal that the polymerization degree of complex viscous units in titanium-bearing slag decreases with increasing MgO and TiO₂ contents. The mechanism of viscosity variation was elucidated. The basic phase in experimental slags is melilite. Besides, as the MgO content increases, the amount of magnesia–alumina spinel in the slag increases. Similarly, the sum of pyroxene and perovskite phases in the slag increases with increasing TiO₂ content.     

一种液奶质量快速检测仪的参数识别新方法

为了提高盒装奶快速品质检测仪阻尼比参数的检测精度和稳定性,提出一种液奶质量快速检测仪的参数识别新方法,该方法根据小波变换原理,利用小波脊线提取检测仪扭摆响应曲线的包络曲线,然后取对数并进行直线拟合来估计系统的阻尼比,并以此参数间接地评价液体盒装鲜奶的变质状况.仿真实验表明,该方法的计算精度和稳定性高于以往的直接计算方法和Hilbert变换方法,可以大大提高盒装奶快速品质检测仪的检测精度和可靠性.     

Trypsin in human milk

Summary Human milk trypsin was purified by adsorption chromatography on cellulose-bound 4-aminobenzamidine; its molecular weight was about 24,000 daltons. Its concentration determined by a radioimmunoassay varies between 2.9 and 5.6 g/l.     

美国东克拉马斯山脉石炭系Bragdon组沉积相和物源区分析

美国加利福尼亚州东克拉马斯山脉上泥盆统■到下石炭统Bragdon组上部含有近3km(构造厚度)的砂岩、泥板岩和砾岩,它们是沉积在一个“混杂的”海底扇环境的浊积岩。详细的沉积相和岩石学研究时盆地发育和物源区分析提供了新的资料,并有助于推新晚泥盆世-早石炭世岛弧的古地理和沉积背景。     

具有快速凝乳性能的水牛奶奶酪菌种筛选

【目的】提高水牛奶产业的经济效益,为广西水牛奶奶酪工业化生产提供参考。【方法】采用平板筛选法从鲜水牛奶和黄牛奶中分离出能够生产水牛奶奶酪的菌种,对筛选到的菌株进行初步的发酵性能试验,并测定其传代稳定性、乳酸和双乙酰含量。【结果】筛选到1株能在4.5h内使水牛奶凝固的菌株;该菌株在最佳发酵温度37℃下,经过厌氧发酵4.5h即可使水牛奶完全凝固,所获得凝乳的黏度为109.2Pa·S,酸度为47.3°T,双乙酰含量为2.826×10-3 g/L,乳酸含量为11.59%。【结论】该菌株产酸能力强、产香性能高、黏度和酸度大、有合适的蛋白质水解特性。     

几种信阳毛尖茶的化学成分研究

以信阳地区栽种茶树品种为材料,研究不同茶树品种和采摘时间茶叶中主要化学成分含量差异.结果表明:水溶性总糖含量(%)在同期春季茶样中差异不显著,含量范围为(8.69~9.62),冬茶中最高(20.90);总黄酮含量(%)在茶树品种间差异显著(P0.05),信阳本地种2最高(9.65);总游离氨基酸含量(%)在茶树品种间的差异极显著(P0.01),信阳本地种1(2.96)本地种2(1.86)福鼎大白茶(0.35),随采摘时间变化显著,且氨基酸种类及其含量差异不同;茶多酚总量(%)在春季茶样中含量范围为7.17~8.38,冬茶中含量最低(0.59),但单酚类物质含量(%)在茶树品种间差异较大,其中没食子酸、表儿茶素和表没食子儿茶素含量随采摘时间变化显著,而冬茶中除没食子酸含量比同种春茶增加81.69%外,其他单酚物质含量均显著下降;生物碱含量(%)在茶树品种间差异明显,随采摘时间延后而下降.     

不同乳化稳定剂对全谷物糙米营养乳稳定性的影响及其配比优化

分析了影响全谷物糙米营养乳饮料稳定性的主要因素,筛选了合适的乳化稳定剂并对其配比进行了优化,探讨了蔗糖和三聚磷酸钠等品质改良剂对体系稳定性的影响。结果表明:全谷物糙米营养乳饮料的乳化剂蔗糖脂肪酸酯与蒸馏单硬脂酸甘油酯的优化复配比例为2∶8,复合乳化剂的添加量为0.20%；筛选出黄原胶、羧甲基纤维素和微晶纤维素为体系的稳定剂,其优化配方为黄原胶0.05%,羧甲基纤维素 0.15%,微晶纤维素 0.08%。进一步发现,蔗糖和三聚磷酸钠可以改善体系的稳定性,但当蔗糖添加量达到4%后,体系的离心悬浮比逐渐降低。     

逆向工程技术及应用

逆向工程技术历经数十年的研究与发展,已经成为产品快速开发过程中重要支撑技术.介绍了逆向工程的基本概念、国内外的发展现状及趋势,并通过牛奶瓶逆向实例分析对数据获取、数据预处理、曲面重构等关键技术进行较详尽的阐述.     

有氧操运动对中年女子身体成分的影响

运用DX-200生物电阻抗人体成分分析仪对30名中年女子身体成分进行测定,并比较经常参加大众健美操和有氧操舞运动对身体成分的影响,结果表明通过经常性的大众健美操或有氧操舞运动,可以使运动者身体脂肪比例下降,改善身体成分,同时参加大众健美操锻炼还可以使瘦体重增加,使运动者的体型趋向健美。