小型制冷装置冷凝器的仿真与实验研究

建立了冷凝器的仿真模型,开发冷凝器稳态模型的仿真软件,搭建翅片管式冷凝器的试验装置,得到冷凝器参数随制冷剂质量流量变化的一系列实验数据.经过比较分析,证明实验数据和仿真结果的变化趋势一致,吻合程度较好.     

大断面轴承钢控轧控冷节能工艺研究

大断面轴承钢由于心部温度下降缓慢，容易引起碳化物成网状析出，破坏其使用性能。传统工艺中必须采用正火热处理加以消除。本文将控制轧制和控制冷却相结合，利用计算机模拟给出了轴承圆钢轧后冷却过程中的温度场分布，提出合理的控轧控冷工艺，从而取代正火工艺，达到节能、优化生产工序目的。     

Study on glass transition and physical aging of polystyrene nanowires by differential scanning calorimetry

In the present study, polystyrene (PS) nanowires in aqueous dispersion with a diameter ranging from 120 to 300 nm are prepared via electrospun and dispersed in water. Relatively, PS nanowires confined in anodic aluminum oxide (AAO) template are prepared through drawing PS flow into the tube of AAO template. Scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) are used to characterize the size of the resultant nanowires and ensure the successful preparation of nanowires. Moreover, the glass transition and physical aging behaviors of the PS nanowires in aqueous dispersion and confined in AAO template are investigated by differential scanning calorimetry (DSC). The PS nanowires in aqueous dispersion and confined in AAO template exhibit different glass transition and physical aging behaviors.     

建立应用程序的多用户登录机制

本文就如何建立有密级应用程序的多用户登录和使用机制,给出了以Ｖｉｓｕａｌ Ｆｏｘｐｒｏ５．０中文版为编程环境而实现的较为具体的例子。从而为较系统、完善地管理用户的注册、登录、使用与注销提供了保障和依据。为应用程序的可靠性,完善性,共享性的改善和提高提出了一条简单有效的途径。     

Regulation of osteoblast functions on titanium surfaces with different micro/nanotopographies and compositions

Surface modification of medical implants is considered as an effective method to improve cellular behaviors and the integration of tissues with materials. Titanium(Ti)-based materials with four different micro/nano-structures and compositions were prepared by acid etching, electrochemical anodization and alkali-heat treatment. The surface morphologies and compositions of the different surface-modified Ti materials were characterized by field-emission scanning electron microscopy(FE-SEM),atomic force microscopy(AFM) and X-ray diffraction(XRD). The effects of the micro/nano structured and compositions of the surfaces on cellular responses were investigated in vitro by observing the morphology, adhesion, proliferation and osteogenic differentiation of osteoblasts. To further investigate the underlying mechanisms, an RT-PCR assay was performed to analyze the expression levels of cell adhesion-related genes. Our results indicated that the nanosized structure and anatase composition could promote the adhesion and proliferation of MC3T3-E1 pre-osteoblast, as well as alkaline phosphatase activity and extracellular matrix mineralization via the integrin-FAK signaling pathway. Taken together, our innovation presented in this work demonstrated that the surface nano-structure design and composition of biomedical implants can be modified of for future orthopaedic applications.     

Innovative designs of permafrost roadbed for the Qinghai-Tibet Railway

Under global warming scenarios, the passive method of simply increasing the thermal resistance by raising the embankment height and using insulating materials has been proven ineffective in warm and ice-rich permafrost areas and therefore could not be used in the Qinghai-Tibet Railway engineering. Instead, a proactive "cooled-roadbed" approach was developed and used to lower the ground temperature in order to maintain a perennially frozen subgrade. The concept that local and site-specific factors play an important role in the occurrence and disappearance of permafrost has helped us to devise a number of measures to cool down the roadbed. For example, we adjust and control heat transfer by using different embankment configurations and fill materials. The Qinghai-Tibet Railway project demonstrates that a series of proactive roadbed-cooling methods can be used to lower the temperature of permafrost beneath the embankment and to stabilize the roadbed. These methods include solar radiation control using shading boards, heat convection control using ventilation ducts, thermosyphons, air-cooled embankments, and heat conduction control using "thermal semi-conductor" materials, as well as combinations of above mentioned three control measures. This road-bed-cooling approach provides not only a solution for engineering construction in sensitive permafrost areas but also a countermeasure against possible global warming.     

NSP窑微量有害组分对筒体腐蚀机理的研究

利用化学分析、ＳＥＭ、ＸＲＤ、ＥＤＡＸ等手段,对ＮＳＰ窑筒体锈层进行分析,从热力学、动力学两个方面探讨硫、氯、碱对筒体的腐蚀机理。结果表明：提高窑体的屏蔽作用,可以抑制筒体腐蚀。     

河工模型相似的精度及误差探讨

本文按照两个相似流动体系必须被同一个物理方程所描述的原理,由水流连续方程的比尺关系导出变态模型的质量守恒误差公式。采用矩阵特征值分析的方法,得到三维流时均流场紊动应力的特征值,并给出了它与模型变率的关系式．由它可分析一维总流分析中的紊动应力相似误差。从概率统计的角度利用实验资料给出泥沙沉降公式,并可与服从Gauss分布的概率公式联解计算出泥沙沉降分布,亦可用于泥沙沉降相似的经验公式λω=λu（λL／λh）^m中指数m的分析与计算。对目前常用的两种泥沙起动相似的经验公式进行分析,并比较了二者的相对误差。     

面向地铁车辆的多胞元铝型材结构压缩吸能特性研究

提出了一种适用于地铁车辆的新型多胞元铝型材吸能结构.此种结构具有形式简单、成本低廉的特点.通过试验测试与数值模拟相结合的方法对该结构的吸能特性展开研究.研究结果表明多胞元铝型材结构的吸能能力稳定,压溃力对冲击速度的变化不敏感.多胞元铝型材结构的压溃力与材料屈服强度、型材壁厚大致呈线性关系.     

新型低位轻放液压支架结构特点及应用研究

提出了一种新型轻型低位放顶煤液压支架,具有重量轻,结构合理,支护效果稳定可靠等特点。该支架已经通过实验室和工业性试验,应用前景广阔。