基于近红外光谱的大鲵肉粉掺伪鉴别及纯度检测

利用近红外光谱技术进行大鲵肉粉的掺伪鉴别及纯度检测。分别采集大鲵纯肉粉、掺入江团鱼肉粉、草鱼肉粉和土豆淀粉的掺伪大鲵肉粉(各40个样本,4类共160个样本)的近红外光谱图。原始光谱经光谱预处理后,利用偏最小二乘-判别分析(partial least square-discriminant analysis,PLS-DA)法分别建立2分类(纯样和掺伪样)和4分类(纯样、掺江团鱼样、掺草鱼样和掺淀粉样)的定性判别模型,利用偏最小二乘回归(partial least squares regression,PLSR)分析法分别建立3类掺伪大鲵肉粉的纯度定量校正模型。结果表明,PLS-DA定性模型中,经一阶导数+多元散射校正光谱预处理后,所建2分类和4分类模型性能均为最佳,校正集和预测集的预测准确率均为100%;PLSR定量模型中,大鲵肉粉掺江团鱼肉粉、大鲵肉粉掺草鱼肉粉和大鲵肉粉掺土豆淀粉模型的校正集相关系数(R_c~2)分别为0.990 6、0.986 4和0.993 3,校正集的均方根误差分别为1.14%、1.39%和0.88%;测试集的相关系数(R_p~2)分别为0.994 4、0.992 4和0.990 8,测试集的均方根误差分别为0.83%、0.89%和1.22%。运用近红外光谱技术结合化学计量学方法能够对大鲵肉粉进行掺伪鉴别及纯度检测。     

Design of the Transmission Lines for 140 GHz ECRH System on HL-2A

A new 140 GHz/2 MW/3 s electron cyclotron resonance heating （ECRH） system composed of two units is now being constructed on HL-2A. As a part of the system, two trans- mission lines marked No.7 ＆ 8 play the role of carrying microwave power from two gyrotrons to the tokamak port. Based on the oversized circular corrugated waveguide technology, an evacu~ ated transmission system with high power capability and high transmission efficiency is designed. Details are presented for the design of the corrugated waveguide, the layout of the proposed lines and the vacuum pumping system. Then mode conversion losses due to coupling, misalignment, bends and gaps are discussed to serve as a reference for analyzing the transmission efficiency and alignment. Finally, a dual-modes propagation case consisting of the HEll and LPn even modes is discussed.     

Investigation of gyrotron-based collective Thomson scattering for fast ion diagnostics in a compact high-field tokamak

As a promising method for fast ion diagnostics,collective Thomson scattering(CTS) can measure the one-dimensional velocity distribution of fast ions with high spatial and temporal resolution.The feasibility of diagnosing fast ions in a compact high-field tokamak by CTS was studied in this work,and the results showed that a wide range of probing frequencies could be applied.A high-frequency case and a low-frequency case were mainly considered for fast ion diagnostics in a compact high-field tokam...     

民办高校仪器分析实验教学改革探讨

以学生为本,从提高学生自学能力和创新能力,培养应用型人才出发,以科学发展观为指导,探讨了仪器分析实验教学实践改革。实践表明:结合各专业实际,通过引进高素质仪器分析人才,更新实验内容和教学方法,完善考核制度,从而突出学生的个性发展,增强学习兴趣,取得较好的教学效果。     

紫外光谱结合偏最小二乘法监测氯化1-羟乙基-3-甲基咪唑离子液体合成反应进程

采用紫外吸收光谱结合偏最小二乘回归建立一种同时快速测定氯化1-羟乙基-3-甲基咪唑离子液体合成反应体系中N-甲基咪唑(IM1)和1-羟乙基-3-甲基咪唑氯化物(IM2)的方法。配制25个样本作为校正集,采用偏最小二乘回归方法和留一交互验证法分别建立IM1和IM2的回归模型,并采用5个样本作为独立验证集评价模型的预测性能。校正模型用于预测氯化1-羟乙基-3-甲基咪唑离子液体合成体系中IM1和IM2含量。结果表明紫外光谱法结合偏最小二乘回归可实现氯化1-羟乙基-3-甲基咪唑离子液体合成过程的近实时监测。     

(-)-表没食子儿茶素没食子酸酯与结合脂肪酸的人血清白蛋白相互作用——柔性对接研究(英文)

为了解脂肪酸(FA)对(-)-表没食子儿茶素没食子酸酯(EGCG)与人血清白蛋白(HSA)的相互作用的影响,本文采用柔性对接技术对配体(EGCG 及其结构片段(-)-表没食子儿茶素(EGC)和没食子酸(GA) )与受体 (结合 FA 的 HSA (FB-HSA)和未结合 FA 的 HSA (FF-HSA) )的相互作用进行预测。结果显示脂肪酸存在时,在位点 1 HSA 与 EGCG 的结合能力明显减弱;而在位点 2 HSA 与 EGCG 的结合能力明显增强,且 EGCG 的对接姿势被原位旋转 180°。研究还发现 EGC 不仅是决定 EGCG 结合模式的核心结构,而且对结合能有重大贡献;GA 仅对结合能具有重要贡献。     

金核壳结构复合纳米颗粒在生物医学中的应用

核壳结构纳米材料是一种新型复合材料。贵金属金纳米核壳材料同时具有核和壳的性质,以及独特的光学、电学、催化性能和良好的生物相容性,因此在生物、化学、医学等领域具有巨大的应用价值。基于文献分析,综述了金及其核壳结构纳米复合颗粒在生物及医学上的应用,包括蛋白质、DNA、细菌和病毒的检测,以及肿瘤热疗、生物成像、生物传感、药物传递与释放等。并对完善制备技术以便更好地应用于临床进行了展望。     

The anode power supply for the ECRH system on the J-TEXT tokamak

The electron cyclotron resonance heating(ECRH) system with a 60 GHz/200 k W/0.5 s gyrotron donated by the Culham Science Center is being developed on the J-TEXT tokamak for plasma heating, current drive and MHD studies. Simultaneously, an anode power supply(APS) has been rebuilt and tested for the output power control of the gyrotron, of which the input voltage is derived from an 80 k V negative cathode power supply. The control strategy by controlling the grid voltage of the tetrode TH5186 is applied to obtain an accurate anode climbing voltage, of which the output voltage can be obtained from 0-30 k V with respect to the cathode power supply. The characteristics of the APS, including control, protection, modulation, and output waveform, were tested with a100 k V/60 A negative cathode power supply, a dummy load and the ECRH control system. The results indicate that the APS can meet the requirements of the ECRH system on J-TEXT.