PBL教学模式在“软件工程”课程教学中的应用

由于学科特性与教学要求,“软件工程”课程教学对实践性和系统性的要求极高。PBL教学模式作为一种自主式教学的新型模式,在教育领域受到广泛关注。文章基于PBL教学模式的特点及优势,结合“软件工程”课程教学改革趋势及教学实践中面临的主要困境,系统分析了PBL教学模式应用于“软件工程”课程教学的途径,以期为促进“软件工程”的课程教学改革及教学质量提高提供参考及借鉴。     

碳脱氧在钢包顶渣改质中的应用

 为了进一步降低夹杂物缺陷并提高产品质量,基于碳脱氧进行了钢包顶渣改质的研究。冷轧产品的生产工艺为铁水预处理→转炉→RH精炼→连铸,为减少钢中夹杂物质量分数,需要进行钢包顶渣改质,同时降低钢包顶渣TFe质量分数。采用粒碳部分替代铝渣球的方法进行基于碳脱氧工艺的钢包顶渣改质,试验结果表明,顶渣改质效果良好,在顶渣TFe质量分数、中间包钢水游离氧明显降低的同时铸坯中Al₂O₃夹杂物得到优化;“30 kg粒渣+铝渣球”工艺降低生产成本5.16元/t(钢)。     

Reducing idle time in event-triggered software execution via runnable migration and DPM-Aware scheduling

Being the main driver of innovation in the automotive industry, vehicle software calls for more efficient tools for its development. Safety-critical applications are predominantly written respecting the AUTOSAR standard, where tasks comprise code-fragments called runnables, and deployed on multi-core architectures. However, task parallelization introduces a substantial number of idle intervals, as runnables have to be mapped and scheduled at design-time without violating data dependencies. In parallelized event-triggered tasks, these intervals are utilized by migrating runnables from the interrupted time-triggered tasks. We propose to also migrate runnables from consecutively scheduled tasks and additionally, to maximize their number using DPM-aware application scheduling.     

致密油藏注天然气提高采收率研究现状

随着我国石油需求量不断增加,致密油藏的开发也愈发重要。如何高效开发致密油藏是一项重点难点,其中致密油藏注天然气提高采收率是一个极具潜力的研究方向。因此,本文着重介绍以天然气作为能量补充介质在国内外的研究现状和应用现状,并且从两相特征等方面总结了理论研究中的一些机理,对致密油藏注天然气提高采收率的发展前景进行了一定的展望。     

ICT and cities revisited

This paper tests whether or not adoption of information and communication technologies (ICT) has offset agglomeration benefits and led to more dispersed spatial structures worldwide. The paper returns to Ioannides et al. (2008) and confirms, first by relying on the Pareto (Zipf) coefficient of the city size distribution as a proxy of spatial dispersion, that the diffusion of fixed telephony has caused more dispersed urban structures worldwide, in other words, greater urban decentralization. Similar causal effects are established for mobile telephony, which are novel, and the internet, which extend previous research. They are confirmed for such alternative measures of dispersion as the Gini coefficient, the Herfindahl index, and the coefficient of variation.     

Interfacial Crystallization of Diacylglycerols Rich in Medium‐ and Long‐Chain Fatty Acids in Water‐in‐Oil Emulsions

The effects of diacylglycerols rich in medium‐ and long‐chain fatty acids (MLCD) on the crystallization of hydrogenated palm oil (HPO) and formation of 10% water‐in‐oil (W/O) emulsion are studied, and compared with the common surfactants monostearoylglycerol (MSG) and polyglycerol polyricinoleate (PGPR). Polarized light microscopy reveals that emulsions made with MLCD form crystals around dispersed water droplets and promotes HPO crystallization at the oil‐water interface. Similar behavior is also observed in MSG‐stabilized emulsions, but is absent from emulsions made with PGPR. The large deformation yield value of the test W/O emulsion is increased four‐fold versus those stabilized via PGPR due to interfacial crystallization of HPO. However, there are no large differences in droplet size, solid fat content (SFC), thermal behavior or polymorphism to account for these substantial changes, implying that the spatial distribution of the HPO crystals within the crystal network is the driving factor responsible for the observed textural differences. MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals to enhance the rigidity of emulsion. This study provides new insights regarding the use of MLCD in W/O emulsions as template for interfacial crystallization and the possibility of tailoring their large deformation behavior. Practical Applications: MLCD is applied in preparing W/O emulsion. It is found that MLCD forms unique interfacial Pickering crystals around water droplets, which promote the surface‐inactive HPO nucleation at the oil‐water interface. Thus MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals, which can greatly enhance the rigidity of emulsion. This observation would provide a theoretical reference and practical basis for the application of the MLCD with appreciable nutritional properties in lipid‐rich products such as whipped cream, shortenings margarine, butter and ice cream, so as to substitute hydrogenated oil. MLCD‐stabilized emulsions can also be explored for the development of novel confectionery products, lipsticks, or controlled release matrices.     

木质素纳米颗粒的制备及其功能化应用研究进展

木质素是一种天然生物质资源，来源广泛，成本低廉。近年来，利用纳米技术将木质素制备成木质素功能化纳米颗粒极大推动了木质素的利用，同时显著解决了传统材料无法解决的突出问题。详细介绍了木质素功能化纳米颗粒的自组装法、机械法、聚合组装法、冻干炭化法等制备方法及其在催化剂、助剂、吸附剂、紫外防护和抗氧化、抗菌、载体材料、聚集诱导发光材料等领域的应用研究，展望了木质素纳米颗粒的应用前景。指出实现木质素纳米颗粒的可控制备、功能化修饰，将有利于推动木质素功能化纳米颗粒在环保、能源、催化和生物医学等领域的进一步应用。     

Effects of solvents and temperature on spherulites of self-assembled phloroglucinol tristearate

Herein, phloroglucinol tristearate (PhgTS) was used to study the crystallization process due to its unique symmetric structure containing a benzene ring and three aliphatic chains. Spherulites of crystallized PhgTS from four solvents under diverse conditions were analyzed in detail and their formation process was studied. Maltese cross is shown by PhgTS spherulites obtained from aprotic solvents via polarized optical microscopy. In comparison, no Maltese cross can be observed from branch-like crystals formed from protic solvents. Independent on the microscaled morphology, lamellae were found to be the basic blocks constructing both PhgTS spherulites and branch-like crystals, which were formed predominantly by stacked PhgTS molecules. Although differential characters of the solvents did not affect the formation of lamellas, the solvents played a crucial role in the formation of self-assembled microscaled morphologies. In particular, the morphologies of spherulites were strongly affected by the concentration of PhgTS solutions, surrounding temperature and evaporation rate of solvents. Generally, a higher concentration of PhgTS led to more homogeneous spherulites, a lower evaporation rate resulted in more compact spherulites, and a higher surrounding temperature generated preferentially more ring-banded spherulites of PhgTS.     

基于虚拟化技术的在线开放课程建设研究--以“常用工具软件”课程为例

随着互联网的迅猛发展,建设在线开放课程成为高职院校信息化教学改革的一个方向。首先通过分析国内外的在线课程现状,发现阻碍在线课程发展的共性问题;然后对"常用工具软件"课程现状进行深入调查、分析和研究,提出将虚拟化技术应用到课程建设中以解决网络教学遇到的问题;最后将研究结论应用到教学实践中,用于提升学生专业能力,提高教学效果。     

天平与砝码计量标准考核中需注意的几个问题

笔者多年在天平与砝码计量标准考核工作中,经常遇到对考核规范理解有误造成计量标准延误考核,现列举几种常见现象并提出解决办法,供建标单位参考。