基于模糊神经元PID算法的注塑机注射速度控制算法研究

基于一款市场较为畅销的注塑机, 设计出一种能精确控制注射速度的模糊神经元PID控制器. 首先, 设计出具有自学能力的神经元PID控制器, 利用模糊算法对其进行优化; 其次, 在原有注射速度线性数学模型的基础上, 构建注塑机注射速度的非线性模型; 最后, 利用MATLAB在所建数学模型的基础上对模糊神经元PID控制器进行仿真实验. 实验结果表明, 所设计控制器具有响应迅速、无超调量、控制精度高、控制稳定等优点.     

基于气体浓度定量的嗅觉刺激器优化设计

现有的基于磁共振测量的嗅觉刺激器，通过调节嗅剂液体浓度的方法可以实现不同浓度的嗅觉刺激，但随着实验进行，受到嗅剂挥发以及实验环境（温度、湿度、气流量）变化的影响，很难确保输送至鼻腔的嗅剂气体浓度的稳定性，进而影响实验结果的准确性．本研究对本实验室前期开发的嗅觉刺激装置进行改进，实现了气体浓度精确定量．改进后的嗅觉刺激器主要分为三个部分：控制系统、反馈系统和气路系统．控制系统主要实现气路系统的送气控制和嗅剂气体浓度调节；反馈系统则负责对气体浓度进行测量；气路系统则在原有基础上添加活性炭装置，降低无关因素干扰．装置改进之后，不同气路切换时间为75.2 ms，比原装置减少了1 s，有效提高刺激精度．实验结果显示，气体浓度调节前，300 s内乙醇、吡啶、乙酸戊酯嗅剂气体浓度分别下降6.7%、71.4%、79.2%，嗅剂气体浓度短时间内发生较大改变．加入气体浓度调节功能后，当气体浓度下降至目标浓度的90%时，可通过调节气泵电压改变嗅剂气流与空气气流比例，从而调节嗅剂气体浓度至目标值，其中吡啶、乙酸戊酯用时13 s．     

Observation of Quantum Beats of Two-Photon-Excited States of Xe upon Photoionization

Optics and Spectroscopy - Ionization of coherently two-photon-excited superposition of 4f states of Xe in a supersonic atomic beam is studied by means of femtosecond pump–probe spectroscopy....     

基于XPS对硫铁矿去除SeO2-3的机理研究

硒是动植物及人体生长必需的十五种微量元素之一，具有清除体内自由基、抗氧化、增强免疫力等功能，但其安全剂量的范围却很窄。利用扫描电子显微镜（SEM）和X射线衍射仪（XRD）对湿法球磨制备的硫铁矿形貌进行了表征。SEM观测发现加乙醇助磨后的硫铁矿为粒径大小较均匀的球形颗粒团聚体，粒径范围在17～200 nm之间，平均粒径138 nm。XRD衍射图谱中的特征峰与FeS₂衍射图谱中各峰位置基本一致，因此判定硫铁矿中主要化学组分为FeS₂，且图谱中基本没有杂峰，表明制备过程中并未混入杂质，样品纯度较高。实验结果表明，该法制备的硫铁矿具有颗粒粒径小、比表面积大、反应活性高等优点。研究中利用X射线光电子能谱仪（XPS）对硫铁矿去除水体中SeO2-₃的机理进行了研究。研究结果表明, （1）在较为广泛的实验pH范围（pH 2.2～11.5），硫铁矿均能有效去除水体中SeO2-₃，去除效率（除pH值7.8以外）均达到90%以上；（2）硫铁矿与SeO2-₃发生反应后，其主要组成元素的XPS特征峰结合能有所减小，表明硫铁矿表面发生了一定化学变化；（3）酸碱环境下硫铁矿去除SeO2-₃的机理不完全相同，酸性环境下，硫铁矿对SeO2-₃的去除是单纯的氧化还原过程，即硫铁矿中被酸活化的S2-₂将SeO2-₃还原为单质Se(0)，并且酸性越强，SeO2-₃去除效果越好；碱性环境下，SeO2-₃的去除过程中氧化还原与络合反应并存，硫铁矿表面有络合态Fe(OH)SeO₃和单质Se(0)两种存在形态，且碱性越强，络合态Fe(OH)SeO₃含量越高。以上研究结果为硫铁矿去除固定水体和土壤中以SeO2-₃为代表的可变价金属阴离子提供重要理论依据和应用基础。     

Effect of the Power-Frequency Electromagnetic Field on the Physicochemical Properties of Aluminum Micro- and Nanopowders

Technical Physics - The effect of power-frequency (50 Hz) electromagnetic field on variation in the physicochemical properties of aluminum powders with different dispersities is studied. It is...     

Model of Dynamics of the IBR-2M Pulsed Reactor with Temperature and Power Fast Feedback Effects

Physics of Atomic Nuclei - A model of dynamics with separate temperature feedback formed by average temperatures of the fuel and the coolant is constructed for the IBR-2M pulsed reactor of periodic...     

Lipidomic-based investigation into the therapeutic effects of polyene phosphatidylcholine and Babao Dan on rats with non-alcoholic fatty liver disease

In recent years, with the improvement of people’s living standards, non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in the world. In this paper, the metabolic disorders in Sprague Dawley (SD) rats were induced by a choline-deficient, l -amino acid–defined (CDAA) diet. The therapeutic effects of polyene phosphatidylcholine (PPC) and Babao Dan (BBD) on NAFLD were observed. Lipidomic analysis was performed using ultra-high-performance liquid chromatography-Orbitrap MS, and data analysis and lipid identification were performed using the software LipidSearch. Both PPC and BBD can reduce lipid accumulation in the liver and improve abnormal biochemical indicators in rats, including reduction of triglycerides, total cholesterol, alanine transaminase and aspartate transaminase in serum. In addition, lipids in rat serum were systematically analyzed by lipidomics. The lipidomic results showed that the most obvious lipids with abnormal metabolism in CDAA diet–induced rats were glycerides (triglycerides and diacylglycerols), phospholipids and cholesterol esters. Both BBD and PPC partly reversed the disturbance to lipids induced by the CDAA diet. PPC may be more effective than BBD in alleviating NAFLD because it has a better effect on inhibiting the abnormal accumulation of lipids and reducing the inflammatory reaction in the body.     

Instantaneous visual imaging of latent fingerprints in water

Science China Chemistry -