植物乳杆菌67干预频次及周期对高脂血症大鼠血脂的影响

目的:探究植物乳杆菌(Lactobacillus plantarum,Lp)67干预频次、周期对高脂血症大鼠血脂的影响。方法:连续4周给大鼠饲喂高脂饲料建立高脂血症大鼠模型,利用益生菌Lp 67结合用于治疗肥胖人群的"间歇性断食法"设计了2组干预组:Lp 67菌悬液(活菌数为108 CFU/mL)1周干预5次(1周中任意5 d灌胃Lp 67菌悬液,其余2 d灌胃生理盐水)的5∶2干预组和Lp 67菌悬液隔日干预组(隔1 d灌胃1次Lp 67菌悬液,其余时间灌胃生理盐水)。干预期间,测定大鼠体质量及干预4、6周和8周时的脏器指数以及血清总胆固醇、总甘油三酯、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇浓度,并与1周干预7次的连续干预组、正常组和模型组比较。结果:与模型组相比,3组干预组均能有效控制大鼠血脂的升高(P<0.05);各干预组间存在显著性差异(P<0.05)。综合而言,Lp 67菌悬液1周干预5次、连续干预6周的大鼠血脂改善效果最显著。结论:益生菌Lp 67干预频次、周期对高脂血症大鼠的体质量、脏器指数、血脂4项生理生化指标以及动脉粥样硬化指数有显著改善作用。     

喷雾反应器中甲烷水合物生长动力学模型

提出了喷雾反应器中甲烷水合物的形成机理,并引入传质对水合反应影响的有效因子等参数,得到了喷雾法生成水合物的改进动力学方程.通过实验验证,实验数据与模型计算数据基本吻合,平均误差为4.63%.方程回归得出甲烷水合物表观活化能(Ea)为54.25 kJ/mol,根据文献结果,说明喷雾反应器中甲烷水合物生长过程由表面反应所控制.     

浅谈孔系位置度的测量

孔系位置度是机械行业比较常见的一种位置公差,其测量一般用坐标法。但因检测设备、人员、及数理知识等原因的限制,目前这种测量方法在我厂还无法开展。经过实际工作的不断实践,探索出一种简单、易行且准确的测量方法。     

车灯座注塑模具设计

通过对车灯座注塑模具的设计,阐述了模具浇注系统的设计方法,旨在降低模具的复杂程度和制造成本;详细介绍了组合式型腔、型芯的结构设计及模具的制造方法。     

《现代大学教育》的文献计量与科学知识图谱研究

通过对学术期刊的历时性研究可以透视某学科或领域的研究热点与发展趋势.基于CSSCI（2006-2012年）的数据,利用CiteSpace软件对《现代大学教育》载文的关键词、作者和参考文献进行了文献计量分析,并做出其知识图谱.结果表明：刊物的载文量呈平稳状态,拥有一批基数庞大、集中度较高的作者群体,少数学术精英对该刊办刊质量起着重要作用;“高等教育质量”、“大学治理与管理”、“研究生教育”、“教育政策与大学发展”及“大学文化与学术文化”是该刊载文所研究的热点,华中科技大学教育科学研究院、厦门大学教育研究院等机构对该刊发展起到了重要支撑作用.     

Experimental Investigation and Thermodynamic Description of the Cu-Zr System

The Cu-Zr binary system is re-investigated via experiment and thermodynamic modeling. Four alloys were prepared by arc melting in order to check the controversial phase equilibria reported in the literature. Both as-cast and annealed alloys were examined by optical microscopy, x-ray diffraction and electron probe microanalysis, and the phase transformation temperatures were measured by differential scanning calorimetry. The intermetallic compounds, Cu₂₄Zr₁₃, Cu₂Zr and Cu₅Zr₈, were demonstrated to be not the stable phases. Based on the literature information and present experimental data, the Cu-Zr system was critically evaluated by means of CALculation of PHAse Diagram approach. A set of self-consistent thermodynamic parameters was obtained, and the calculated phase diagram and thermodynamic properties are in a satisfactory agreement with the experimental data.     

High-Throughput Determination of Interdiffusion Coefficients for Co-Cr-Fe-Mn-Ni High-Entropy Alloys

In this report, a combination of the diffusion multiple technique and the recently developed pragmatic numerical inverse method was employed for a high-throughput determination of interdiffusivity matrices in Co-Cr-FeMn-Ni high-entropy alloys (HEAs). Firstly, one face-centered cubic (fcc) quinary Co-Cr-Fe-Mn-Ni diffusion multiple at 1373 K was carefully prepared by means of the hot-pressing technique. Based on the composition profiles measured by the field emission electron probe micro analysis (FE-EPMA), the composition-dependent interdiffusivity matrices in quinary Co-Cr-Fe-Mn-Ni system at 1373 K were then efficiently determined using the pragmatic numerical inverse method. The determined interdiffusivities show good agreement with the limited results available in the literature. Moreover, the further comparison with the interdiffusivities in the lower-order systems indicates the sluggish diffusion effect in Co-Cr-Fe-Mn-Ni HEAs, which is however not observed in tracer diffusivities. In order for the convenience in further analysis, a generalized transformation relation among interdiffusivities with different dependent components in multicomponent systems was finally derived.     

Weldability and microstructural variations in weldments of Ti-5Ta-1.8Nb alloy

The successful replacement of the present generation of corrosion-resistant materials (nitric acid-grade stainless steel and Ti) by Ti-5Ta-1.8Nb, which has better corrosion resistance, depends on its weldability characteristics. This article presents the results of a study on the fabrication, qualification, and microstructural characterization of the welds. Welding was carried out using the direct current electrode negative (DCEN) polarity tungsten inert gas (TIG) (manual) welding method with high-purity Ar shielding. Testing was carried out as per the ASME standard (section IX, welding and brazing). Qualification tests found that the weldment met the required properties. The weldment showed heterogeneous microstructures, which are rationalized based on differences in phase transformation mechanisms that are dictated by the thermal cycles experienced by various microscopic regions. The results, described in this article, confirm that the weldability of the developmental Ti-Ta-Nb alloy is excellent. A preliminary evaluation of the corrosion behavior of the welds showed rates comparable to that of the base metal, establishing that this alloy could be considered as an alternative material for use in highly corrosive environments.     

Template-free hydrothermal synthesis of single-crystalline SnO<Subscript>2</Subscript> nanocauliflowers and their optical properties

Large-scale single-crystalline SnO₂ nanocauliflowers were successfully synthesized using a hydrothermal growth method without any template. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). FE-SEM images show that the as-grown SnO₂ nanocauliflowers are constructed of tetragonal prisms with a width of 500–600 nm. XRD, EDS, and SAED results indicate that the as-grown SnO₂ nanocauliflowers are single crystalline with the tetragonal rutile crystalline structure. The growth mechanism of SnO₂ nanocauliflowers is also preliminarily discussed on the basis of different Sn(OH)₆²⁻ concentrations, and it is found that Sn(OH)₆²⁻ concentration plays an important role in determining the shape of the prepared SnO₂. Room temperature photoluminescence was further carried out on SnO₂ nanocauliflowers to investigate their optical properties. An intense blue luminescence centered at a wavelength of 424 nm is observed in the as-grown SnO₂ nanocauliflowers.