基于Dirichlet多项式混合模型的复杂人体行为识别

在健康智能照顾护理领域,日常行为识别的准确率至关重要,但是由于日常行为本身的动态可变性以及个体之间的差异性的特点,造成基于可穿戴设备的日常行为识别模型的泛化性差、识别率低,无法对复杂日常行为进行识别的问题。提出一种优化的特征提取方法,将手腕动作聚合为若干个高层语义主题,进而将日常行为表征为一个有序的高层语义主题序列,有效地提升分类的效果。实验结果表明,高层主题语义特征能更准确地表征复杂日常行为的特征,提高了行为识别的准确性。     

不同条件下合成活性尖晶石粉的研究

研究了在不同成分条件下用氧化镁和氧化铝合成镁铝尖晶石的方法,阐述了温度、成分、颗粒大小、晶格活性对合成过程的影响,并提出了较理想的合成镁铝尖晶石的工艺条件。     

Highly efficient methanol electrooxidation catalyzed by co-action of PdY2O3 in alkaline solution for fuel cells

Catalytic activity improvement by Pd-based catalyst for methanol oxidation is significant to the development of alkaline direct methanol fuel cells. Herein, we demonstrate the performance of methanol oxidation on Pd catalyst could be greatly increased by Y₂O₃. The promotion effect is discussed with the help of physical and electrochemical characterization techniques by comparing with a home-made Pd/C catalyst in the identical condition. The presence of Y₂O₃ in the system is well confirmed by the characteristic peaks indicated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy(XPS); and a strong electronic effect between the Pd and Y₂O₃ is reflected by an evident shift of binding energy to the lower direction as shown in the XPS spectrum. The catalytic activity expressed by current density reveled by cyclic voltammetry is about 145 mA cm^?2, 1.5 times higher than that of the reference catalyst; current retaining ability of 5 times higher than that of the reference catalyst is revealed by Chronoamperometry. Higher catalytic activity and stability for methanol oxidation is discussed due to the relatively well dispersed Pd particle size, increased electroactive surface area and the synergistic interaction of Pd and Y₂O₃. The work demonstrates the hybrid PdY₂O₃/C as a newly effective catalyst for alkaline direct methanol fuel cells.     

基于作业成本法的制造企业内部物流管理研究

物流贯穿于产品的流动过程之中,从原材料采购到成品分销这一物流过程横穿了企业的各职能部门,因此物流对于现代企业的发展和竞争能力的发挥起着非常重要的作用。本文结合卫浴制造企业,研究制造企业内部的物流理问题。将作业成本法（Activity-based Costing,简称ABC）原则扩展到企业业务流程中去,提出一种改进的企业业务流程,缩短产品生产周期,控制企业成本,提高制造企业的竞争力。     

学习内容管理系统开发中的问题及对策

学习内容管理系统是解决教学资源库和课程整合问题的一个重要手段,文章重点探讨了学习内容管理系统的定义问题、角色问题、教学设计问题、系统架构问题和标准应用问题,希望能为更好地开发和应用学习内容管理系统提供有针对性的建议。     

面向状态的车间控制策略研究

当前的生产计划和控制系统较好地解决了企业中期的物料需求计划与能力需求计划问题,而车间以下层次的生产作业计划与控制是其薄弱环节。这里通过对现代车间生产活动控制的功能、目标和现代车间制造系统基本特征的考察、分析,揭示了现代车间控制的根本矛盾,提出了面向状态的车间控制策略和方法并进行了应用研究。     

扩展的似化学理论在二元熔渣体系中的应用

评述了适用于最大有序体系热力学优化分析的扩展似化学理论及优化方法,并利用该理论对6个二元熔渣体系不同温度下的组元活度值进行了计算,计算值与实验数据总平均相对误差分别为10.40%和6.34%,与实验数据吻合较好。该理论中所需参数ω及η可通过优化拟合实验数据得到,可调节性强、表达式简单实用,该理论在预测冶金熔渣的热力学性质方面具有较大优势。     

n-C4H10 autothermal reforming over MgO-supported base metal catalysts

We report n-C₄H₁₀ autothermal reforming over MgO-supported base metal catalysts at 723 K. Catalytic performance was investigated not only after H₂ treatment at 1073 K (reductive treatment) but also after subsequent O₂/Ar treatment at the reaction temperature (oxidative treatment) to mimic the shutdown and startup of a domestic fuel cell system. After reductive treatment, both Ni/MgO and Co/MgO exhibited high n-C₄H₁₀ conversion and hydrogen formation activity; the stability of Ni/MgO was better than that of Co/MgO. The reaction route was investigated by measuring activity at various contact times. The results revealed that n-C₄H₁₀ autothermal reforming over Ni/MgO is a multi-step reaction composed of combustion, steam reforming, water gas shift reaction, and methanation. In contrast, Cu/MgO and Fe/MgO did not show reforming activity but cracking and combustion of n-C₄H₁₀. Ni/MgO and Co/MgO catalyzed H₂ formation even after the oxidative treatment. However, the initial activity of Co/MgO after the oxidative treatment was lower than that after the reductive treatment and a decrease in H₂ formation rate was again observed after 6 h in Co/MgO, similar to the measurements after the reductive treatment.     

水热合成硅酸钙外加剂作用机理探讨

外加剂能显著地改善活性不高的硅质原料水热合成微孔硅酸钙的工艺过程 ,本文就外加剂的作用机理进行了试验研究。