铝合金加工防腐蚀水基型切削液的研制与试验

介绍了铝合金材料在切削液作用下进行切削加工时的腐蚀机理,确认铝合金在水基型切削液中腐蚀的主要原因是细菌微生物大量繁殖及其胞外分泌物对乳化体系的影响。针对这一问题,研制了一款适合铝合金加工且具有良好润滑、冷却、防锈性能的防腐蚀水基型切削液。进行铝合金与YG6硬质合金在油基型切削液和防腐蚀水基型切削液作用下的摩擦试验,确认防腐蚀水基型切削液能达到与油基型切削液相近的减摩效果,在节能环保的同时,可以提高铝合金零件加工表面的抗腐蚀性能。

Friction and Wear Performance of Boron Doped, Undoped Microcrystalline and Fine Grained Composite Diamond Films

Chemical vapor deposition （CVD） diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don＇t have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond （BD-UM-FGCD） film is fabricated by a three-step method adopting hot filament CVD （HFCVD） method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond （BDD） layer, the extremely high hardness of the middle undoped microcrystalline diamond （UMCD） layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond （FGD） layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti-frictional components.

Al-B_(2)O_(3)-CeO_(2)-粉煤灰复合增强涂层成分设计及冲蚀磨损分析

为了提高粉煤灰作为增强材料在金属基复合材料中的应用和性能,通过热力学分析和正交优化试验确定Al-B_(2)O_(3)-CeO_(2)-粉煤灰复合增强涂层各成分之间可能发生的反应及最佳配方比例,采用等离子喷涂在ZG310-570基体制备了粉煤灰复合增强涂层,分析了粉煤灰复合增强涂层的表面形貌、物相和冲蚀磨损性能。结果发现,热力学分析和正交优化试验表明Al、B_(2)O_(3)、CeO_(2)和粉煤灰之间能发生固相反应,粉煤灰复合增强涂层配方最佳比例质量分数为粉煤灰55%、B_(2)O_(3)20%、Al20%、CeO_(2)5%;粉煤灰复合增强涂层呈凹凸不平的片层状结构,致密性好,存在纵向裂纹、未充分融化颗粒和孔隙;X射线分析表明粉煤灰复合增强涂层有Al_(2) O_(3)、CeB_(6)、2MgO·SiO_(2)、3CaO·B_(2)O_(3)等新相生成,与热力学分析结果一致;在一定冲蚀时间和冲蚀角度下,不同冲蚀转速时ZG310-570基体表面粉煤灰复合增强涂层的相对耐冲蚀磨损性能比基体分别至少提高了20.41倍、22.43倍和23.17倍。

Corrosion Behavior of Plasma Transferred Arc Fe-based Coating Reinforced by Spherical Tungsten Carbide in Hydrochloric Acid Solutions

Fe-based coatings reinforced by spherical tungsten carbide were deposited on 304 stainless steel using plasma transferred arc(PTA) technology.The composition and phase microstructure of the coatings were evaluated using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS) and X-ray diffraction(XRD).The corrosion behaviors of the coatings in 0.5 mol/L HCl solution were studied using polarization curve and electrochemical impedance spectroscopy(EIS) measurements.The experimental results shows that the tungsten carbide improves the corrosion resistance of the Fe-based alloy coating,but increase in the mass fraction of tungsten carbide leads to increasing amount of defects of holes and cracks,which results in an adverse effect on the corrosion resistance.The defects are mainly present on the tungsten carbide but also extend to the Fe-based matrix.The tungsten carbide,acting as a cathode,and binding material of Fe-based alloy,acting as an anode,create a galvanic corrosion cell.The binding material is preferentially corroded and causes the degradation of the coating.

肠道菌群失调与肺部感染患者应激反应及免疫功能的相关性研究

目的探讨肠道菌群与肺部感染患者机体炎症应激反应和免疫功能的相关性。方法选取2019年6月至2020年6月瑞安市人民医院收治的肺部感染患者80例为研究对象(观察组),另选同期60名健康体检者为对照组。采集两组新鲜粪便进行培养,记录肠道菌群双歧杆菌、乳酸杆菌、拟杆菌和肠球菌的菌落数。通过ELISA法检测两组血清炎症因子IL-6、IL-8及TNF-α水平。比较两组一氧化氮(NO),丙二醛(MDA)和肌酸激酶同工酶(CK-MB)含量。采用FACS Calibur流式细胞仪检测两组CD3^(+)、CD4^(+)、CD8^(+)的含量,并计算CD4^(+)/CD8^(+)比值。分析肠道菌群与炎症因子、应激反应和免疫功能的相关性。结果观察组双歧杆菌、乳酸杆菌、拟杆菌菌落数分别为(4.16±0.48)、(5.28±0.57)和(4.06±0.59)lg CFU/g,均低于对照组(t=-32.064、-16.568和-21.665,P均<0.05);而肠球菌菌落数为(8.73±1.29)lg CFU/g,高于对照组(t=25.435,P<0.05)。观察组IL-8、IL-6、TNF-α、NO、MDA和CK-MB水平分别为(155.79±22.38)pg/mL、(192.43±40.16)pg/mL、(131.54±19.27)pg/mL、(11.32±1.21)μmol/L、(10.54±2.74)μmol/L和(145.15±12.49)U/L,均高于对照组(t=40.710、30.716、36.730、27.188、11.430和18.738,P均<0.05);观察组CD3^(+)、CD4^(+)、CD8^(+)水平及CD4^(+)/CD8^(+)比值分别为(45.32±4.69)%、(25.54±3.74)%、(20.15±2.49)%和(1.25±0.34),均低于对照组(t=-9.095、-15.147、-6.244和-3.807,P均<0.05)。Pearson相关性分析表明,双歧杆菌、乳酸杆菌、拟杆菌与IL-8、IL-6、TNF-α、NO、MDA和CK-MB水平均呈负相关,与CD3^(+)、CD4^(+)、CD8^(+)、CD4^(+)/CD8^(+)比值均呈正相关(P均<0.05);肠球菌与IL-8、IL-6、TNF-α、NO、MDA和CK-MB水平呈正相关,与CD3^(+)、CD4^(+)、CD8^(+)、CD4^(+)/CD8^(+)比值呈负相关(P均<0.05)。结论肺部感染时,肠道菌群失调与机体炎症应激反应及免疫功能相关,肠道菌群对肺部感染的发生发展可能存在影响。

基于实践导向的应用型创新创业人才培养模式重构

高校师生在创新创业教育中存在的不足,主要表现为学生认知能力不足和知识体系单一、教师重视度不够和与社会需求脱节、课程内容质量有待提高等。文章通过实训再造模式、立体化教学模式和能力培养模式等人才培养体系的重构,搭建了"四位一体"的创新创业综合实训平台,构建了"点—线—面—体"的创新创业课程群立体化教学模式、"五层四级一线"创新创业实践教学模式,完善了"校企政"联动机制,实施了能力递进人才培养模式,提高了学生工程实践能力、学科交叉能力和创新创业能力。

基于创新实践的《工程材料与成型工艺》课程教学模式研究与实践

针对《工程材料与成型工艺》课程和学生在学习过程中存在的问题,如课程枯燥单调、缺乏吸引力等,作者开展了基于创新实践的《工程材料与成型工艺》课程教学模式研究与实践,实行“先预习后教,教后学生内化,最后隔堂讨论”的教学模式,注重“理论与实践相结合,过程与结果相结合”,激发了学生学习的兴趣和主观能动性,提高了学生的创新实践能力。

基于创新创业人才培养的工程训练中心教学研究与实践

目前,工科类高校在人才培养过程中存在着平台功能单一、学生创新能力不强、创新意识薄弱、创新创业持续性低、创新创业师资队伍知识储备不够等问题。工程训练中心作为工科类高校中教学规模最大、学生受众人数最多的实践教学基地,要承担起培养学生创新能力和素质的重要职责。辽宁工程技术大学搭建了以工程训练中心为主体的“一体五翼”的创新创业综合平台,优化了工程训练教学内容,加强了师资队伍建设和产教融合,有效地提高了学生的多学科交叉能力、工程实践能力、创新创业能力。