复杂性测度在肌电信号模式识别中的应用

针对表面肌电信号(SEMG)的非平稳特性,提出了一种以复杂性测度和支持向量机(SVM)相结合的肌电信号模式识别新方法。肌电信号的复杂度作为一种新的肌电信号特征,算法简单。支持向量机是一种新的机器学习机制。通过对采集的四通道表面肌电信号进行分析,提取其复杂性测度信息构建特征矢量,利用“一对一”分类策略和二叉树构建的多类支持向量机分类器,很好地实现了对前臂的八种动作表面肌电信号的模式分类。实验表明,由支持向量机对肌电信号的复杂度特征进行分类,具有很好的稳定性和准确率,为肌电信号及其它非平稳生理电信号的模式分类提供了一种新思路。     

基于Web的非精确反向推理专家系统研究与实现

介绍了一个基于Web的精确反向推理专家系统原型,通过对其增加非精确推理功能,完成了对此原型的改进,使其能进行非精确分类或诊断。提出在推理过程中对所使用的规则、条件等信息的收集及处理算法,并给出一个推理过程分析实例,论述了对原型改进的基本步骤,同时也提供了一个知识库例子。探讨基于Web的专家系统的应用实践,对于推动专家系统在我国的应用具有现实意义。     

粘贴DNA计算模型的几种分子逻辑门的实现

理论上来说,基于DNA的分子逻辑门是DNA计算机体系结构的产生基础和DNA计算机实现技术的硬件基础。在这篇论文中,我们在先前提出的基于粘贴DNA计算模型的分子逻辑与门的实现方法的基础上,进一步提出了基于粘贴DNA计算模型的分子逻辑或门和与非门的实现方法。与先前方法类似,逻辑门、输入信号和输出信号是DNA分子。可以实现OR,NOT和NAND类型的逻辑门操作。需要使用包括聚合酶链反应(PCR),琼脂糖凝胶电泳,探针的标记与检测等生物工程技术。这些技术集成于DNA芯片中可用于DNA计算机的研制。     

柴油机内部EGR的数值模拟分析

应用大型通用CFD软件STAR-CD及网格生成软件ES-ICE,对带有内部EGR的柴油机进气及压缩过程缸内三维瞬态流场进行数值模拟研究,并分析其组分浓度及温度的分布情况,通过研究掌握内部EGR对缸内温度、浓度场的影响,为进一步研究内部EGR对缸内燃烧的影响奠定基础。     

磁性生物炭非均相类Fenton体系去除水中四环素

采用先浸渍后热解的方法制备了磁性生物炭材料,并使用XRD、XPS、VSM对制备的材料进行了表征。结果表明,制备的磁性生物炭主要的活性物质为γ-Fe2O3。采用磁性生物炭非均相类Fenton体系处理水中四环素(TC),当初始TC质量浓度为200 mg/L,pH=7,H2O2投加量为19.8 mmol/L,磁性生物炭投加量为3 g/L时,处理效果最佳。加入抗坏血酸可以加速铁循环过程,明显改善·OH的生成,进而增强了TC去除率。     

固废制备微晶泡沫玻璃的研究进展

为实现固体废弃物的高值化利用,从微晶泡沫玻璃的制备机理、工艺流程及温度制度等方面分析了工业固体废弃物制备微晶泡沫玻璃的可行性,重点论述了金属矿尾矿、赤泥、高炉矿渣、煤矸石、粉煤灰等固体废弃物制备微晶泡沫玻璃的国内外研究进展,并对微晶泡沫玻璃的研究和发展趋势进行了展望。     

于都黄麟-祁禄山地区土地质量地球化学评价

通过对于都县黄麟-祁禄山地区开展1:5万土地质量地球化学调查,在野外土壤样品采集和化验测试的基础上,系统地研究了影响土地质量的各项地球化学指标特征与控制因素,基本查明有益元素、重金属元素分布,划分出重点污染区和绿色土地发展区,并进行土地质量等级评价,为永久基本农田建设、土地资源开发与利用等方面提出建议。     

Study on depositing SiO2 nanoparticles on the surface of jute fiber via hydrothermal method and its reinforced polypropylene composites

To improve the interfacial compatibility of jute fiber reinforced polypropylene (PP) composites, hydrothermal method was used to deposit SiO₂ nanoparticles on the surface of pretreated jute fibers and the effect of reaction factors (tetraethoxysilane [TEOS] concentration, ammonia concentration, and reaction temperature) on the deposition of SiO₂ nanoparticles were evaluated. The results of FTIR, XRD, SEM, and TEM showed that the amorphous SiO₂ nanoparticles with an average particle size of 65.0 nm were successfully deposited on the surface of jute fibers at the TEOS/H₂O volume ratio of 1:2, ammonia of 0.55 M, reaction temperature of 100 °C (0.15 MPa) for 5 h. Compared with the sol–gel method, SiO₂ nanoparticles obtained by the hydrothermal method possessed smaller particle size and were less agglomerated, which can better fill in the surface defects of the jute fibers and result in a 12.9% increase in the tensile strength. The study on the mechanical properties and interface performance of the jute fiber reinforced PP composites indicated that the interfacial compatibility between jute fibers and PP was obviously improved. The tensile and impact strength of the composites reinforced with nano‐SiO₂ deposited jute fibers were increased by 26.87% and 25.65%, respectively, compared with the untreated jute fibers. J. VINYL ADDIT. TECHNOL., 26:43–54, 2020. © 2019 Society of Plastics Engineers     

Determination of a suitable index for a solvent via two-column extractive distillation using a heuristic method

The traditional approach to solvent selection in the extractive distillation process strictly focuses on the change in the relative volatility of light-heavy components induced by the solvent. However, the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility. This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost. The functional relationship between the relative volatility and the total annual cost is established, where the main factors, such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent, are taken into account. Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model. The results show that using the solvent with the minimal two-column extractive distillation index, the process achieves a minimal total annual cost. The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification.