壳聚糖固定化单宁酸酶的特性研究

研究了以壳聚糖为载体交联-吸附单宁酸酶后的化学特性。结果表明：固定化单宁酸酶（简称“ITA”）的最适反应pH为3.0,原酶（简称“TA”）为5．5;ITA最适反应温度为50℃,TA为40℃;ITA的Km（app）为1．3845×10(-1)mol／L,TA为6．7500×10(-5)mol/L;ITA在pH3．0～8．0的范围内残存酶活大于60％,ITA在pH3．0～6.0范围内残存酶活大于60％;ITA在80℃的水浴中保温1h,酶活力仍未见下降,而TA在60℃水浴中保温30min酶已失活;ITA和TA在4℃和30℃的条件下,贮藏20d后,ITA的残存活性大于40％,TA的残存活性小于20％。     

余吾煤业S2107工作面瓦斯涌出规律研究

研究综采工作面瓦斯涌出规律是煤矿瓦斯治理的重要基础。以余吾煤业S2107工作面为研究对象,采用等价替换法估算、画图法实测采空区瓦斯涌出量,单元法实测工作面瓦斯源,得出正常生产期间采空区瓦斯涌出量、工作面漏风及各单元瓦斯涌出规律,为综放工作面瓦斯治理提供了条件。     

Rollback reconstruction for TDC enhanced perfusion imaging

Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis.However,the low rotational speed of the C-arm(6-8 s per circle)is a chal-le...     

基于二氧化硅平面光波导的强度均衡的光脉冲对的产生

提出了一种基于平面光波导工艺的带有可调定向耦合器的非对称MZI结构.模拟结果显示,当定向耦合器的两个耦合臂的折射率独立改变时,定向耦合器的调制效果较好;当调制电极与耦合区的波导间距为0时,两个耦合臂的温度差达到最大.测试得到,AMZI的插入损耗为2.05 dB,延迟时间为151.4 ps,脉冲对的功率比近似为1.该器件有助于提高集成QKD器件的性能.     

Study on Stabilizing Mechanism of Konjac Glucomannan in Tea Infusions

ABSTRACT:  The stabilizing mechanism of konjac glucomannan (KGM) in tea infusions was studied using a conventional transmission electron microscope (TEM), scanning electron microscope (SEM), ethanol sedimentation, and other methods. As a result, many water-soluble complexes among the KGM molecules and tea components such as thearubigins (TRs), theaflavins (TFs), total catechins (TC), and tea polyphenols (TPP) were obviously formed in tea infusions with addition of KGM. The aggregations of tea components, which caused tea cream down, were decreased because of KGM addition and the stability of suspended particles in tea-KGM infusions was enhanced. These findings suggested that the strong adsorption happened among KGM and tea components and particles through strong hydrogen bonding functions. Molecular weight of KGM in tea infusions was smaller than that in water solution. In water solution, it was 4.83 × 10⁵, but in black tea infusions 3.41 × 10⁵, and in oolong tea infusions 3.51 × 10⁵. The experiments also revealed that the tea-KGM infusions had stronger antielectrolyte coagulation capacity and the static electrification action exists among the molecules of tea infusions. These findings indicated that KGM could be a useful stabilizer for stability of the tea infusions.     

The kinematic analyses of the 3-DOF parallel machine tools

A 3-degree-of-freedom (3-DOF) parallel machine tool based on a tripod mechanism is developed and studied. The kinematics analysis is performed, the workspace is derived, and an analysis on the number of conditions of the Jacobian matrix and manipulability is carried out. A method for error analysis and manipulability is introduced. Hence, the manipulability analysis of the parallel machine tool is accomplished.     

The Kinematic Analyses of the 3-DOF Parallel Machine Tools

A 3-degree-of-freedom(3-DOF)parallel machine tool based on a tripod mechanism is developed and studied.The kinematics analysis is performed,the workspace is derived,and an analysis on the number of conditions of the Jacobian matrix and manipulability is carried out.A method for crror analysis and manipulability is introduced.Hence,the manipulability analysis of the parallel machine tool is accomplished.     

Research progress in anisotropic magnetoresistance

Anisotropic magnetoresistance (AMR) is an important physical phenomenon that has broad application potential in many relevant fields. Thus, AMR is one of the most attractive research directions in material science to date. In this article, we summarize the recent advances in AMR, including traditional permalloy AMR, tunnel AMR, ballistic AMR, Coulomb blockade AMR, anomalous AMR, and antiferromagnetic AMR. The existing problems and possible challenges in developing more advanced AMR were briefly discussed, and future development trends and prospects were also speculated.     

港珠澳大桥U肋角焊缝超声相控阵探伤技术

为解决港珠澳大桥8 mm厚U肋角焊缝探伤问题,进行了U肋角焊缝超声相控阵探伤技术分析,通过焊接试件的探伤试验,考察了该焊缝超声相控阵探伤的检测精度,提出的U肋角焊缝的超声相控阵探伤检测及判定方法,可以指导港珠澳大桥U肋角焊缝的无损检验工作,同时为其它桥梁此类焊缝的无损检验提供借鉴。主要取得了以下两项成果:一是根据U肋角焊缝的缺陷特征,建立了焊缝探伤数学模型,并在此基础上提出了基于超声相控阵技术的缺陷信号图像端点读值法,简化了探伤检测过程,提高了检测精度;二是提出了基于检测误差的U肋角焊缝探伤判定方法,较好地解决了焊缝探伤中的漏判与误判问题。     

基于机器视觉的咖啡生豆快速检测与分级研究

目的 为了实现咖啡生豆的快速无损等级评估,建立一种基于机器视觉的咖啡生豆快速检测分级方法。方法 本次研究提取咖啡生豆图像预处理后的形状和颜色共13种特征,首先通过特征分布图分析与主成分分析找到13类缺陷豆的显著特征,并确定其显著特征值范围来判定缺陷豆,然后对正常豆按粒度大小判断其等级,最后在MATLAB App Designer平台上设计了咖啡生豆快速检测与分级界面。结果 研究表明,利用机器视觉技术能很好地识别各个类别咖啡生豆,检测一级咖啡生豆准确率为94.77%、二级为93.2%、三级为95.85%,13类缺陷豆平均准确率为82.25%,咖啡生豆检测平均准确率达到91.52%,检测300g咖啡生豆总用时25.3156s。结论 提高了咖啡生豆分级的智能化水平,分级过程平稳且快速,为今后咖啡生豆在线检测分选提供了技术支持。