纳米Mn3O4的快速制备及其对亚甲基蓝的类芬顿催化氧化性能

采用氧化沉淀法,以Mn(NO₃)₂·H₂O为锰源、NH₃·H₂O为沉淀剂、H₂O₂为氧化剂,在温和条件下反应1 h制备了粒度均匀的纯相纳米Mn₃O₄。以亚甲基蓝溶液为模拟染料废水,考察了纳米Mn₃O对亚甲基蓝的类芬顿催化氧化效果。结果表明,当Mn₃O₄加入量为0.5 g/L时,对25 mg/L亚甲基蓝的降解率可达80.3%。     

Dynamic performance analysis of turbine flow sensor based on CFD simulations

The research on the dynamic performance of flowmeters has great significance for the accurate measurement of flow onsite. A simulation method for dynamic characteristics of turbine flow sensor was proposed in this study. This method was used to investigate the dynamic performance of three turbine flow sensors with different diameters. The amplitude-frequency characteristic, phase-frequency characteristic, transfer function, and step response are analyzed based on the results of the simulation. The results indicate that turbine flow sensors can be analyzed as a first-order system. The frequency of pulse flow is the main factor affecting the sensor's performance. The phase difference increases as the frequency increases, and the maximum phase difference reaches 50°. The gain of the small-diameter turbine flow sensor is susceptible, while the phase difference and time constant of the large-diameter turbine flow sensor are susceptible. For step flow, the time constant generated by the negative step is larger than that by the positive step. The analysis results provide bases for evaluating the dynamic performance of turbine flow sensors used online.     

一种新型免疫遗传算法

标准遗传算法存在收敛速度慢、过早成熟等缺点。借鉴生物免疫系统中抗体注射免疫的理论,提出了一种基于抗体注射的新型免疫遗传算法（AIGA）。该算法在保留标准遗传算法随机全局搜索能力的基础上,引进了生物免疫系统的免疫应答、抗体注射、免疫选择等机制。结合TSP问题,给出了示范抗体的提取和注射方法,并给出了算法收敛性的理论证明。最后,用AIGA算法对100个城市的TSP问题进行了仿真计算,并将其计算过程与标准遗传算法进行了对比,结果表明该算法能有效地改善遗传算法的不成熟收敛缺陷,使收敛的速度有较大的提高。     

翅碱蓬籽油脂提取工艺优化及理化性质测定

以沧州沿海地区盐地翅碱蓬籽为原料,以石油醚(60~90℃)为提取剂,以提油率为指标,采用浸出法提取翅碱蓬籽油。利用正交实验法和响应面法对颗粒度、液料比、提取时间进行优化,并对两种方法进行了双样本T检验,结果表明两种实验方法的最佳工艺条件下提油率差异不显著。正交实验优化的最佳工艺条件为:颗粒度100目、液料比20:1(mL:g)、提取时间150 min,此时提油率平均达到25.13%。响应面法优化后的最佳工艺参数为:颗粒度100目、液料比21:1(mL:g)、提取时间128 min,此时提油率平均可达到25.12%。对响应面最佳条件下得到的翅碱蓬籽油进行理化性质分析,检测结果为:皂化值199.09 mg KOH/g,碘值141.58 g I/100 g,酸值2.00 mg KOH/g,过氧化值2.53 mmol/kg,均符合食用油标准,具备开发为高级保健食用油的条件。研究结果为翅碱蓬的进一步开发利用提供了理论依据。     

基于CDIO教学理念“C#程序设计”的教学改革

针对传统"C#程序设计"的教学缺点,运用CDIO教学理念对该门课程进行教学改革。介绍了以学生为中心,"做中学"的教学体系,简述了"C#程序设计"这门课程的教学组织、教学方法和考核模式的改革内容及具体实施方案。     

MSTP技术在矿区专网中应用的可行性研究

在矿区通信中,利用MSTP技术在优先保证话音业务的前提下,有效传送各种数据业务,将是近期城域传输网建设的重中之重。不过电信运营商的业务种类非常多,用户类型也比较复杂,传统的MSTP肯定是不能满足需求的,所以运营商开始引入PTN、IPRAN等技术;不过城域网接入用户业务需求相对简单,最关键的是MSTP技术高度成熟,组网和运营成本也比较低。对MSTP技术进行了内涵分析,进行了具体的应用需求分析,详细探讨了MSTP技术在矿区专网中应用的方案,取得了比较好的效果。     

Effects of Y2O3 doping on the phase composition,chemical diffusion coefficient and electrochemical properties of CaHfO3 proton conductor

In order to further understand the effect of Y₂O₃ doping on the electrical conductivity of CaHf_1−xY_xO_3−δ, which was prepared by conventional solid-state reaction. The electrical conductivity of CaHf_1−xY_xO_3−δ was measured by two-terminal AC method in an oxygen-rich atmosphere, hydrogen-rich atmosphere and water vapor-rich atmosphere at the temperature between 973 and 1373 K. The test results show that the conductivity of CaHf_1−xY_xO_3−δ first increases and then decreases with x from 0.08 to 0.20, and its total conductivity and conductivity activation energy are 3.88 × 10⁻⁷ to 5.34 × 10⁻⁵S/m and 0.76–0.92eV respectively. Combined with the test results of the H/D isotope effect, it is found that protons are the main conductive carriers in the three different atmosphere at temperatures range of 973–1173 K. In addition, in the temperatures range of 1273–1373 K, the positive holes are the main conductive carriers in the oxygen rich atmosphere, and the vacancies participates in the conductive process as the main conductive carriers in the water vapor rich atmosphere. The chemical diffusion coefficients of CaHf_1−xY_xO_3−δ is 3.9 × 10⁻⁶ to 2.4 × 10⁻⁵ cm²/s in the temperature range of 973–1373 K. According to the test results of electromotive force, the theoretical electromotive force is consistent with the measured electromotive force. The proton transfer number of CaHf_1−xY_xO_3−δ exceeded 97% in hydrogen atmosphere at temperatures from 973 to 1173 K. In sum, these findings of CaHf_1−xY_xO_3−δ can be used as alternative materials for hydrogen sensor electrolytes.     

Porous nitrogen-doped carbon vegetable-sponges with enhanced lithium storage performance

Porous nitrogen-doped carbon vegetable-sponges (N-DCSs) have been fabricated by chemical treatment of the Cu@C precursors using HNO₃ for the first time. The obtained N-DCSs are porous three-dimensional (3D)-structure and similar to numerous agglomerated fluffy micro-vegetable-sponges. When the precursors are treated by H₂SO₄, carbon vegetable-sponges (CSs) without nitrogen doping are prepared. As anode materials in lithium ion batteries, the as-prepared N-DCSs show improved Li-storage capacity and cycling stability as compared with the pure CSs. They offer 870 mA h g⁻¹ at 0.5 A g⁻¹ after 300 cycles and high reversible capacity with 910 mA h g⁻¹ at 0.2 A g⁻¹ after cycled at different current densities, which are much higher than those of CSs. It is envisaged that the large surface area, unique 3D porous nanostructure and appropriate nitrogen doping are favorable for the superior electrochemical properties of N-DCSs.     

响应面法优化超声辅助提取金丝皇菊多糖工艺及生理活性研究

以金丝皇菊为试验材料,采用响应面分析法优化超声辅助提取金丝皇菊多糖的工艺,在单因素试验的基础上,以多糖提取率为响应值,依据Box-Behnken中心组合试验设计建立数学模型,优化金丝皇菊多糖的提取工艺。通过测定对O2-·、·OH、DPPH和ABTS自由基的清除作用评价其抗氧化活性,并初步探究温度和光照对其稳定性的影响。结果表明,金丝皇菊多糖最佳提取工艺为提取温度70℃、超声功率102W、乙醇浓度90%,多糖提取率为84.06mg/g,与预测值83.76mg/g相符。金丝皇菊多糖具有较好的抗氧化活性,当浓度为0.1mg/mL时,对DPPH、·OH、O2-·和ABTS自由基的清除率分别为64.73%、53.24%、51.93%、55.69%,IC50值分别为0.061、0.095、0.098和0.091mg/mL,且金丝皇菊多糖在常温(20℃)及避光条件下保留率最高,表现出较好的稳定性。     

响应面法优化超声辅助提取金丝皇菊多糖工艺及生理活性研究

以金丝皇菊为试验材料,采用响应面分析法优化超声辅助提取金丝皇菊多糖的工艺,在单因素试验的基础上,以多糖提取率为响应值,依据Box-Behnken中心组合试验设计建立数学模型,优化金丝皇菊多糖的提取工艺。通过测定对O2-·、·OH、DPPH和ABTS自由基的清除作用评价其抗氧化活性,并初步探究温度和光照对其稳定性的影响。结果表明,金丝皇菊多糖最佳提取工艺为提取温度70℃、超声功率102W、乙醇浓度90%,多糖提取率为84.06mg/g,与预测值83.76mg/g相符。金丝皇菊多糖具有较好的抗氧化活性,当浓度为0.1mg/mL时,对DPPH、·OH、O2-·和ABTS自由基的清除率分别为64.73%、53.24%、51.93%、55.69%,IC50值分别为0.061、0.095、0.098和0.091mg/mL,且金丝皇菊多糖在常温(20℃)及避光条件下保留率最高,表现出较好的稳定性。