基于“卓越计划”的工程图学课程改革

从培养具有工程实践能力、工程设计能力和工程创新能力的卓越人才出发,分析了工程图学的教学现状,重新构建了工程图学的新的教学体系,从教学内容、教学方法、实践环节、考核方式以及工程图学教师队伍建设等方面对工程图学课程进行了改革。     

注塑模数字化设计技术研究

阐述了一种注塑模数字化设计技术.运用Pro/E软件的通用功能模块和模架设计专家(EMX)模块,进行塑件及注塑模设计.以相机面壳注塑模设计为例,验证了该方法的可行性.该方法可以提高塑料注射模具的开发效率.     

鲜活水产品运输车环境控制装置研究

针对水产品运输车箱体环境设计过程中所采取的水温控制方法,设计了一款鲜活水产品运输车环境控制系统,并利用SolidWorks软件中的Flow Simulation模块对控制装置的降温效果进行了仿真分析.仿真结果表明,水体环境的散热响应好,降温效果明显,可以满足运输过程中鲜活水产品对环境温度的要求.     

Influence of temperature,ripening time,and cosurfactant on solvothermal synthesis of calcium phosphate nanobelts

Calcium phosphate nanobelts were prepared by solvothermal synthesis method using CTAB as surfactant and n-pentanol as cosurfactant. The influence of temperature, ripening time, and cosurfactant on the morphology and crystallization of calcium phosphate nanobelts were investigated by TEM, FTIR, and XRD. It was found that the crystallinity and crystallite size increased with the increase of synthetic temperature and ripening time. Pentanol also played an important role in influencing the size and morphology of calcium phosphate nanoparticles as well as water conduit. A possible growth mechanism was proposed that layer or lamellar precursor might roll into 1-D nanobelts under the force provided by the temperature and pressure gradient.     

Si掺杂对溶液等离子喷涂TiO2涂层结构及光催化性能的影响

目的采用溶液前驱体等离子喷涂制备TiO_2以及Si掺杂TiO_2涂层,并分别研究H2流量和Si掺杂对TiO_2涂层光催化性能的影响。方法通过X射线衍射、扫描电子显微镜、拉曼光谱和傅里叶变换近红外光谱表征样品的晶相、表面形貌以及化学结构,然后以甲基橙为目标物,借此模拟有机污染物,利用光化学反应仪测试TiO_2以及Si掺杂TiO_2涂层的光催化性能。结果适量Si掺杂可以细化晶粒,提升TiO_2涂层中锐钛相含量(从7.4%提高到49%),同时形成Ti—O—Si键,Si掺TiO_2涂层甲基橙的降解率达到95%左右,高于纯TiO_2涂层80%的降解率。随着H2流量增加,TiO_2涂层中的晶粒明显粗化,主要以金红石相的形式存在,H2流量为8 L/min的TiO_2涂层甲基橙降解率达到82%,要远高于H2流量为4、10 L/min的52%和33%。结论 Si掺杂TiO_2涂层比纯TiO_2涂层的光催化性能更优,当H2流量为8 L/min时,光催化性能最好。     

热处理温度对大气等离子喷涂316L不锈钢涂层组织和性能的影响

目的研究316L不锈钢涂层在不同热处理温度下组织结构和性能的变化规律,提高该涂层的摩擦学性能。方法利用大气等离子喷涂(APS)技术制备316L不锈钢涂层,对喷涂态涂层进行300~700℃热处理。通过光学显微镜(OM)和X射线衍射仪(XRD)观察分析涂层的显微组织和相组成,利用维氏硬度计测试涂层的显微硬度值。采用摩擦磨损试验机和三维光学显微镜测试涂层的摩擦系数和磨损率,利用场发射扫描电子显微镜(FE-SEM)观察磨痕表面并对磨损机制进行深入分析。结果喷涂态316L不锈钢涂层的厚度约为350?m,显微硬度值为335HV0.1,涂层组织中含有未熔颗粒、孔隙和氧化物等。在干摩擦条件下,涂层的摩擦系数稳定在0.75左右,磨损率为(1.329±0.14)×10-5 mm3/(N·m)。随着热处理温度的升高,涂层扁平颗粒界面处的氧化行为明显,同时涂层内部的孔隙缩小,涂层结构更加致密,使得涂层显微硬度提高了30%。涂层的耐磨性能在700℃热处理条件下最佳,磨损率为(1.149±0.26)×10-5 mm3/(N·m),较喷涂态涂层降低14%,磨损机制以疲劳磨损和粘着磨损为主。结论热处理有助于提高316L不锈钢涂层的显微硬度,700℃热处理可有效提高涂层的耐磨性。     

Buckling behaviour of imperfect ring-stiffened cone–cylinder intersections under internal pressure

Cone–cylinder intersections are used commonly in pressure vessels and piping. In the case of a cone large end-to-cylinder intersection under internal pressure, the intersection is subject to a large circumferential compressive force. While both the cone and the cylinder may be locally thickened to strengthen the intersection, it is often desirable and convenient to provide an annular plate ring at the cone-to-cylinder joint to supplement local thickening or as an alternative strengthening measure, leading to a ring-stiffened cone–cylinder intersection. Only limited work has been carried out specifically on ring-stiffened cone–cylinder intersections under internal pressure. This paper presents the first experimental study on such intersections. In addition to the presentation of test results including geometric imperfections, failure behaviour and the determination of buckling mode and load based on displacement measurements, results from nonlinear bifurcation analysis using the perfect shape and nonlinear analysis using the measured imperfect shape are presented and compared with the experimental results.     

Thermal characteristics of tree-shaped microchannel nets with/without loops

Several tree-shaped microchannel networks with/without loops are numerically examined and compared for application in cooling of electronic components. The physical model of microchannel electronic cooling system is set up with tree-shaped networks. The tree-shaped microchannel nets are embedded in a disk-shaped heat sink, which is attached to a chip to remove the heat dissipated by a chip. The effects of total branching level and loops on the thermal and flow performances of heat sink system are investigated numerically. Results show that tree-shaped nets with loops provide a great advantage when the structure experiences accidental damage to one or more channel segments since the loop assures continuity of coolant flow. Under blockage of some branches, the channel networks only experience an increase of pressure drop while maintaining the capability to remove the heat generated by the chip.     

一种提高液压缸速度响应的模糊PI控制方法

对进口节流调速速度负载特性进行了分析,提出了一种基于模糊PI控制策略的方法,以提高液压缸速度响应。建立了进油节流调速的液压缸动力学模型;通过光栅尺对液压缸位移进行测量,并计算出相应的速度,与给定速度进行比较,确定控制策略。仿真和实验结果表明:采用模糊PI控制与线性改变节流口开度相比,模糊PI控制能提高液压缸的速度响应。     

Corrosion and corrosion fatigue of AISI 420C (X46Cr13) at 60 °C in CO2-saturated artificial geothermal brine

The lifetime reduction of cyclically loaded AISI 420C (X46Cr13, 1.4034) constantly exposed to highly corrosive CO₂-saturated hot thermal water is demonstrated in in situ-laboratory experiments (60 °C, brine: Stuttgart Aquifer, flowing CO₂: 30 L/h). S–N plots, micrographic-, phase-, fractographic- and surface analysis were applied to obtain sustainable information on the corrosion and corrosion fatigue behavior. Maximum number of cycles (here 12.5 × 10⁶ cycles to failure) is reached at σ_a = 173 MPa. Hydroxide and siderite layers were found on pits and crack surfaces. No typical fatigue limit exists and pit corrosion prior to crack initiation may be identified as failure cause.