在线考试系统中USB端口的监控与管理

随着工业技术的成熟,USB设备特别是U盘越来越廉价,这给在线考试系统带来了新的挑战。这就需要在考试系统中对USB端口进行有效的管理,实现考试过程的便利性和安全性,也是公平性的一个体验。该文通过对Windows底层设备管理的分析,设计了一种基于Windows底层API的USB端口管理方法,并通过Delphi编程语言实现。实验表明,该方法在考试过程中能有效地监控和管理USB端口,从而保证考试的公正性和权威性。     

食品安全与食品伦理道德体系建设

本文认为,应该将食品安全定义为:食品中不应含有有毒、有害物质或因素;符合人体的营养要求;具有相应的色、香、味、形等感官性状。我国食品安全形势依然严峻。绝大多数情况下,食品安全问题是靠伦理道德约束的,法律法规也只有在借助于道德被提升为人们的内心信念和行为标准时,才能有效实施。“法德并济”是必要的。文章提出了食品伦理道德体系建设的途径和方法,包括制定食品伦理道德规范、强化道德规范教育、塑造道德楷模、强化舆论宣传、培育企业自我监督机制、利用利益机制调控、建立企业的信用系统等。     

不同有机氮源对山药-食药用真菌“双向发酵”的影响

以含有活性成分的山药为培养基质,接种食药用真菌菌种（灵芝、蛹虫草、银耳和香菇）进行“双向发酵”,使山药原有成分转化形成新成分。以菌丝布满基质时间、基质消耗率、菌质折干率、菌质的自由基清除率为评价指标,考察不同有机氮源（黄豆粉、玉米蛋白粉、花生蛋白粉、谷朊粉和酵母浸粉）对各山药-食药用真菌“双向发酵”的影响。结果表明,不同有机氮源对菌丝布满基质的时间、菌质折干率影响不显著（P＞0.05）,对基质消耗率和自由基清除率影响均显著（P＜0.05）。添加酵母浸粉对山药-灵芝适应性提高最多（11.02分）;蛹虫草和银耳添加有机氮源后适应性分别降低为18.81分和16.45分;添加有机氮源对山药-香菇适应性均可提高,玉米蛋白粉提高最多（28.65分）。     

From plastic-waste to H2: A first approach to the electrochemical reforming of dissolved Poly(methyl methacrylate) particles

The development of sustainable processes for the recycling of plastic is a major environmental issue to reduce the pollution by this kind of waste. The electro-oxidation of plastic wastes in electrolysers powered by renewable energies is a promising option to produce hydrogen at low temperature while diminishing the energy demand compared to Oxygen Evolution Reaction (OER). Poly (methyl-methacrylate) (PMMA) particles, a widely used polymer, were dissolved (0.1–2% wt.) in an isopropanol(IPA)/H₂O binary solvent and electro-oxidized on Pt/C-based electrodes in a liquid batch electrochemical cell at 70 °C in acidic media. Despite the dissolution strategy, polymer macromolecules partially block the accessibility of the active sites of a commercial electrode and strongly degrades its electrochemical performances mainly linked to IPA electro-oxidation. The preparation of a more porous electrode supported on carbon paper was found to strongly hinder this deactivation. Furthermore, the electrooxidation of PMMA or PMMA-derived molecules can be performed during cyclic voltammetries up to 1.4 V and chrono-amperometries at 1.4 V.     

南水北调中线工程水源区产业融合水平评价及提升策略

为促进南水北调中线工程水源区一二三产业融合水平,从融合动力、融合环境、融合过程、融合效应四个维度出发,遵循前瞻性、动态性等原则,构建评价指标体系,运用熵值法对南水北调中线工程水源区产业融合发展水平进行实证分析.结果表明,水源区产业融合发展水平总体较低,且区际差距明显,产业融合发展水平大体呈现以丹江口库区为中心逐步往外递...     

Catalytic hydropyrolysis of crop straws with different biochemical composition

In this study, four kinds of straws with different biochemical compositions, including soybean straw (SS), peanut straw (PS), rice straw (RS), and corn straw (CS), were subjected to catalytic hydropyrolysis (HyPy) to explore the influence of biochemical composition on the products distribution and properties of the pyrolysis oil. The HyPy reactions were performed at 400 °C for 2 h with added 10 wt% Pd/C and 4 MPa H₂. During the HyPy, hydrogen and catalyst broke the coating structure and hydrogen bond between cellulose (CL) and hemicellulose (HCL), and thus significantly weakened the biochemical composition effect on the yield and elemental composition of the bio-oil. The bio-oil yield varied between 11.75 wt% and 13.05 wt%, and the C, H, N, O, and S content fell into the following ranges of 82.06–85.15 wt%, 9.24–9.61 wt%, 1.18–1.43 wt%, 4.62–7.86 wt%, 45–130 ppm, respectively. Biochemical composition of straw, especially the mass ratio of CL to HCL (m_CL/m_HCL), markedly influenced the molecular composition of the bio-oil. Hydrocarbons (20.15–46.66%) and phenolic compounds (17.01–47.98%) accounted for the vast majority of the identified compounds. SS and PS with higher m_CL/m_HCL (1.92 and 1.80, respectively) tended to produce bio-oils with more aromatics (22.63% and 20.70%, respectively) and fewer phenolic compounds (17.01% and 22.56%, respectively).     

基于随机并行梯度下降算法的InSAR相位解缠方法

相位解缠是干涉合成孔径雷达InSAR数据处理中的一个关键步骤,解缠结果的好坏直接影响最终数字高程模型的精度。介绍了一种基于随机并行梯度下降SPGD算法的解缠方法,该方法对图像中各相位点施加随机并行扰动,通过迭代使得解缠误差代价函数收敛到全局最优值,从而实现相位解缠的目的。模拟和实测数据实验结果表明,相较于最小二乘解缠方法,随机并行梯度下降解缠算法精度更高,且原理简单,易于实现,为相位解缠提供了一个全新的思路。     

融知识传授与能力培养于启发式教学过程

《物理化学》是化学化工的理论基础,逻辑性、实用性都很强。结合《物理化学》精品课程建设,提出了实现知识传授与能力培养的统一的教学改革思路,探索以启发式教学为主的教学方式,在学生能力培养方面取得了一定的成效。     

AVR单片机与VRAM型彩色液晶模块接口电路及驱动程序设计

以AVR单片机为控制核心,以LR035VRAM彩色液晶模块为人机界面,介绍ATmega1280单片机与VRAM型彩色液晶模块接口之间的设计方法。通过分析液晶模块的时序,阐述了在ATmega1280单片机中用软件模拟时序的方法,给出了基于ICCAVR编程语言的驱动程序设计模块,实现了对液晶模块LR035VRAM的显示控制。同时,将其成功移植应用在某火炮仿真瞄准训练显示系统中。     

合成甲氧苄氨嘧啶缩合产物同分异构体的分析和转化工艺研究

对以三甲氧基苯甲醛为原料合成甲氧苄氨嘧啶(TMP)的缩合产品中的同分异构体2-甲氧甲基-3-(3,4,5-三甲氧苯基)-丙烯腈(Ⅰ)和2-(3,4,5-三甲氧基苄基)-3-甲氧基丙烯腈(Ⅱ)的相对含量提出了用高效液相色谱分析的方法,其中色谱柱为C18柱,流动相为四氢呋喃-水(体积比为30∶70),检测波长为320 nm。并对同分异构体的相互转化工艺进行了优化,当缩合产品的用量为15 g时,甲醇钠用量为27 mL,用35 mL无水乙醇或乙二醇单甲醚作溶剂,一次回流温度和时间为80°C和2 h,二次回流温度和时间分别为84~86°C和3 h时,其中可进行环合反应所需的同分异构体Ⅱ的相对含量转化至99%以上。