可变温条件下材料表面的双向反射分布函数测量

基于双向反射分布函数单一参考测量法的测量原理，研制了一套测量温度最高可达500℃的双向反射分布函数测量系统。系统利用转角装置来实现不同角度位置的变换，用加热炉对试样进行加热，采用模糊PID控制器进行温度的控制。在25℃～500℃的温度范围内，对铜表面的双向反射分布函数进行了测量实验，光源采用可见光波长0．6328μm，功率约8mW的HeNe激光器，选用Si1336-5BK光电探测器。实验表明：随着试样表面温度的升高，铜表面的BRDF测量值发生了改变；在温度上升或下降到同一温度时，铜表面的BRDF测量值不同。最后，对实验现象的形成机理进行了深入分析。上述实验结论对材料表面空间反射特性的研究具有重要意义。

常压射流等离子体发射光谱研究

使用改进介质阻挡放电装置生成常压射流等离子体,采用光纤光栅光谱仪在300-1000 nm范围记录了不同放电电压的氩气发射光谱,并比较了空气和氩气常压介质阻挡放电等离子体发射光谱,分析发现氩气发射光谱中的谱线都是氩原子的发射谱线,表明常压射流装置产生的等离子体全部为氩等离子体,而无其他空气成分参与放电。为测量电子激发温度,选用相距较近的763.51和772.42 nm两条光谱线对电子温度进行分析,结果表明电子激发温度的范围在0.1-0.3 eV,而且它还随着放电电压的增加而增加。初步使用“红外测温仪”测量被处理材料表面温度,结果发现材料表面的温度也随着放电电压的增加而增加,范围在50-100℃,材料表面温度的变化趋势可以近似表征等离子体宏观温度变化趋势。通过分析常压射流等离子体的温度特性,探讨了常压射流等离子体温度对材料改性研究的意义。

浅谈阳台的利用

随着人民物质文化生活水平的不断提高，人们对居住环境要求越来越高，利用阳台发展居室空间，已被许多老房及住房标准不高的住户所接受，本文就利用阳台变为做饭场所出现的问题，在设计上提出一些解决办法。

低温液体储运装备真空表征与监测研究

提出了以绝热材料外表面温度表征低温储运装备内真空度的新方法,从理论上构建了真空度与绝热材料外表面温度的对应关系,采用低温多层绝热材料表观热导率测试平台,获得了不同真空度下绝热材料外表面温度,证实了该表征方法的有效性。该方法可以实现低温储运装备内部真空度的长期可靠监测,同时具有成本低,操作简单的优势,对于低温储运装备的长期安全使用具有重要的实用价值。

Feasibility Study on Cryogenic Milling of Carbon Fiber Reinforced Silicon Carbide Composites

Carbon fiber reinforced silicon carbide matrix(Cf/SiC)composites have the most potential application for high-temperature components of aerospace high-end equipment.However,high cutting temperature,rapid tool wear and severe surface damages are the main problems in dry cutting Cf/SiC composites process.The feasibility study on cryogenic milling of Cf/SiC composites using liquid nitrogen as coolant is investigated.Influences of milling parameters and coolant on temperature,cutting force,surface quality and tool wear are investigated,which is compared with dry cutting.Experimental results reveal that the cutting temperature in cryogenic milling of Cf/SiC composites is reduced by about 40%—60%compared with dry cutting.The milling force increases gradually with the increase of spindle speed,feed rate,depth and width of milling in cryogenic milling process.In addition,the machined surface quality in cryogenic milling is superior to that in dry cutting process.Fiber fracture,matrix damage and fiber matrix debonding are main material removal mechanisms.Flank face wear is the main wear form of the polycrystalline diamond(PCD)end mills.The tool life is prolonged in the cryogenic milling process because the reduced temperature inhibits the softening of Co binder and phase transition of diamond in the PCD end mills.

Control of Pavement-Surface Temperature-Rise Using Recycled Materials

High temperatures of the asphalt concrete pavements in summer contribute to the heat island phenomenon in the urban areas. The effective cool-pavement technologies are sought to mitigate the pavement environment. In this paper, developed heat-reflective pavements are constructed from open-graded asphalt concrete, in which voids in the upper part of the pavement are filled with a cement mortar, containing recycled materials as a fine aggregate. The recycled materials used in this study are： crushed oyster shells, roof tile debris, pottery debris, glass cullet, crushed escallops and coral sand. The temperature reduction of the pavement surfaces at an open site is measured in the summer. The results show that the maximum surface temperature of the pavements falls by approximately 8-10 ℃ compared to the asphalt concrete pavement. Furthermore, it is found that the temperature reduction is mainly due to the increased solar radiation reflectance of the pavement surface.

Effect of pyrolysis temperature on properties of ACF/CNT composites

Activated carbon fiber/carbon nanotube(ACF/CNT) composites were fabricated by chemical vapor deposition(CVD) process.The effects of pyrolysis temperature on properties of ACF/CNT composites,including BET specific surface area,mass increment rate and adsorption efficiency for rhodamine B in solution,were investigated by scanning electron microscopy.The results show that the pyrolysis temperature is a key factor affecting the qualities of ACF/CNT composites.The mass increment rate and BET specific surface area sharply decrease with the increase of pyrolysis temperatures from 550 ℃ to 850 ℃ and the minimum diameter of CNTs appears at 750 ℃.The maximum adsorption efficiency of ACF/CNT composites for rhodamine B is obtained at 650 ℃.ACF/CNT composites are expected to be useful in adsorption field.

Perpendicularly Self-Oriented and Shape-Controlled L10-FePt Nanorods Directly Synthesized by a Temperature-Modulated Process

The synthesis and self-assembly of tetragonal phase-containing L10-Fe55Pt45 nanorods with high coercive field is described. The experimental procedure resulted in a tetragonal/cubic phase ratio close to 1：1 for the as-synthesized nanoparticles. Using different surfactant/solvent proportions in the process allowed control of particle morphology from nanospheres to nanowires. Monodisperse nanorods with lengths of 60 ＋ 5 nm and diameters of 2-3 nm were self-assembled in a perpendicular oriented array onto a substrate surface using hexadecylamine as organic spacer. Magnetic alignment and properties assigned, respectively, to the shape anisotropy and the tetragonal phase suggest that the self-assembled materials are a strong candidate to solve the problem of random magnetic alignment observed in FePt nanospheres leading to applications in ultrahigh magnetic recording （UHMR） systems capable of achieving a performance of the order of terabits/in2.