利用理化参数鉴别掺假蜂蜜

利用几种理化参数快速、准确鉴别蜂蜜与糖浆。以北方地区常见的17种蜂蜜和10种糖浆为研究对象,通过理化参数(水分、多酚、黄酮含量、pH值、蛋白质含量及分子质量范围、单糖含量比等)分析蜂蜜和糖浆的异同。为了提高果糖和葡萄糖的分辨率,采用氨基色谱柱,在流动相的选择上进行了优化。结果显示,pH值、多酚含量、黄酮含量无明显区别。水分含量、单糖含量比、蛋白质含量及其分子质量范围有区别:1)蜂蜜、糖浆的w(水)范围分别为15.13%~19.88%、 22.13%~28.50%;2)蜂蜜、糖浆的果糖与葡萄糖质量分数比分别为0.95~1.50、 0.13~2.80;3)蜂蜜中w(蛋白质)范围为1.12~5.09μg/g,分子质量范围为45.0~116.0kDa,糖浆中不含蛋白质。将蛋白质含量测定与蛋白质分子质量测定相结合,增强了通过蛋白质鉴别真假蜂蜜的说服力。水分含量、果糖与葡萄糖质量分数比、蛋白质含量及分子质量可作为掺假鉴别的指标,为蜂蜜的掺假鉴别提供理论依据。     

现代学徒制模式下跨企业培训中心建设的实践探索

现代学徒制有利于促进行业、企业参与到职业教育人才培养全过程,是一种切实可行的职业人才培养形式。苏州健雄职业技术学院在推进现代学徒制培养体系上进行了十年探索,建立了连接学校和企业间的人才培养平台——跨企业培训中心。实践表明,依托跨学校跨企业的"双跨"培训中心,实现了校企协同、平台互通、资源共享,为现代学徒制人才培养提供了有效路径。     

Effect of Ce addition on microstructures and mechanical properties of A380 aluminum alloy prepared by squeeze-casting

The effect of cerium (Ce) addition on the eutectic Si, β-Al₅FeSi phase, and the tensile properties of A380 alloy specimens prepared by squeeze-casting were studied by optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The experimental results showed that Ce more effectively modified the eutectic Si and refined the β-Al₅FeSi. The refinement effect significantly increased under a specific pressure of 100 MPa with the addition of Ce from 0.1wt% to 0.9wt%. In contrast, the average length and the aspect ratio of the eutectic Si and β-Al₅FeSi exhibited their optimal values when the content of the added Ce was greater than 0.5wt%. Needle-like Al8Cu4Ce was precipitated with the addition of excessive Ce; hence, the mechanical properties of A380 gradually decreased with increasing Ce content in the range from 0.3wt% to 0.9wt%.     

综合传动装置悬置系统刚度灵敏度分析与振动能量解耦

基于综合传动装置悬置系统6自由度耦合振动模型,利用灵敏度分析方法,计算悬置系统各阶固有振动频率关于各悬置各方向刚度的灵敏度,确定影响某一方向振动的关键橡胶刚度,为改善系统某一方向的振动提供理论依据.以系统各方向振动解耦率作为目标函数,综合考虑传动轴激励、人体承受振动敏感区域及各向振动耦合状况来确定优化约束条件,进行刚度参数最优化,得到的悬置系统各方向最优刚度值可用于改善悬置系统隔振性能.针对某一传动系统振动恶化的情况,采用刚度灵敏度分析与振动能量解耦综合方法,对悬置系统进行设计.最后利用台架振动试验结果验证悬置系统优化设计的有效性.      

Improved dehydriding property of polyvinylpyrrolidone coated Mg-Ni hydrogen storage nano-composite prepared by hydriding combustion synthesis and wet mechanical milling

In this work, polyvinylpyrrolidone(PVP) coated Mg_(95)Ni_5 nano-composites were prepared by hydriding combustion synthesis(HCS) plus wet mechanical milling(WM) with tetrahydrofuran(THF) and donated as WM-x wt% PVP(x = 1, 3, 5 and 7) respectively. The phase compositions, microstructures and dehydriding property, as well as the co-effect of PVP and THF were investigated in detail. XRD results showed that the average crystal size of MgH_2 in the milled Mg_(95)Ni_5 decreased from 23 nm without PVP to 18 nm with 1 wt% PVP. The peak temperature of dehydrogenation of MgH_2 in the milled Mg_(95)Ni_5 decreased from 293.0 ℃ without THF to 250.4 ℃ with THF. The apparent activation energy for decomposition of MgH_2 in WM-7 wt% PVP was estimated to be 66.94 kJ/mol, which is 37.70 kJ/mol lower than that of milled Mg_(95)Ni_5 without THF and PVP. PVP and THF can facilitate the refinement of particle size during mechanical milling process. Attributed to small particle sizes and synergistic effect of PVP and THF, the composites exhibit markedly improved dehydriding properties.     

Effect of minor Sc on the microstructure and mechanical properties of AZ91 Magnesium Alloy

The as-cast and heat-treated microstructures and mechanical properties of the AZ91 magnesium alloys with and without minor Sc addition were investigated and compared in this paper. The results indicated that adding0.15–0.45 wt% Sc to the as-cast AZ91 alloy not only could modify and refine the Mg_(17)Al_(12) phase but also suppress the formation of the Mg_(17)Al_(12) phase. At the same time, the grains of the Sc-containing as-cast AZ91 alloys were also effectively refined. As a result, the mechanical properties at room temperature(RT) for the Sccontaining as-cast AZ91 alloys were effectively improved. In addition, adding 0.15–0.45 wt%Sc to the AZ91 alloy promoted the formation of the continuous precipitates(CP) during the aging treatment in spite of that the formation of the discontinuous precipitates(DP) was simultaneously suppressed. Accordingly, the Sc-containing as-aged AZ91 alloys obtained the relatively higher mechanical properties at RT than the as-aged AZ91 alloy.     

钢渣吸附去除水中亚甲基蓝

通过静态批式实验研究钢渣对亚甲基蓝吸附行为的影响.结果表明:亚甲基蓝去除率随钢渣投加量的增加而增大,随初始浓度的升高而降低,而单位钢渣质量下亚甲基蓝的吸附量呈相反趋势.溶液初始pH值为4时最有利于钢渣吸附亚甲基蓝.钢渣吸附亚甲基蓝符合Lagergren准一级动力学方程,平衡吸附量随亚甲基蓝初始质量浓度的增加而增大,随钢渣投加量增加而减小.结合Freundlich等温吸附方程发现,钢渣对亚甲基蓝的吸附是以离子交换作用为主的优惠型吸附.亚甲基蓝阳离子在静电力作用下吸附在钢渣表面,并与CaO等反应形成聚合物,增强吸附效能.     

基于脉搏波数学模型的运动员运动状态判别方法

针对利用运动员脉搏波信息对其运动状态(高强度运动、平静)进行判别,并减少身体状态的随机性对脉搏波特征信息的影响问题,提出了一种对原始脉搏波信号进行建模进而提取特征信息进行状态判别的方法.利用训练-测试的二分类分析方式,对运动员的心率状态进行判别,以分析运动员的运动状态,辅助其进行运动训练工作.实验通过对10名运动员志愿者在不同状态下进行脉搏波采集,对预处理后的原始信号进行函数建模并提取生理信息,利用SVM进行监督训练和测试.结果表明,该方法能够对运动员心率状态进行有效判别,得到运动员的运动状态.     

基于专利分析的中国海洋生物肥料发展现状与发展建议

【目的】为了解国内海洋生物肥料的知识产权现状,明确海洋生物肥料的研究热点及其发展趋势。【方法】对国内有关海洋生物肥料的公开专利进行检索分析,主要从年度专利申请量、区域分布、技术领域、申请机构类型和词频分析进行数据整理。【结果】海洋生物肥料专利申请数量增长迅速,其中山东省在海洋生物资源农业应用领域领先全国,广西位于全国前列。企业在专利申请数量上远高于科研院所和高校。62%专利涉及的相关工艺为海洋原材料简单物化处理技术,其他的则为采用微生物发酵或酶解技术。专利词频分析表明,海藻是海洋生物肥料领域使用最普遍的原材料。【结论】海洋生物肥料市场潜力巨大,但其在应用上仍处于原材料收集利用的初级阶段,深入挖掘利用海洋微生物资源能够促进生物肥料产业的升级换代。广西拥有丰富的海洋生物资源,也有微生物工业应用的经验和基础,研发人员应在原有海洋生物利用的基础上,充分利用海洋微生物资源提升产品功效,促进广西农业绿色发展。     

基于语料库的虚拟语气研究简

基于语料库的虚拟语气研究表明：中国英语学习者在使用虚拟语气方面并不理想,不同水平学习者在使用上存在差异,学习者的英语水平与误用的频率正相关,产生误用的原因主要是语际迁移,语内迁移、教学失误等.