硅烷偶联剂对多孔硅的稳定化研究

为了将多孔硅应用于含能材料的制备,采用电化学双槽腐蚀法制备了平均孔径4.3 nm,厚度超过100μm的不龟裂多孔硅薄膜,利用硅烷偶联剂(KH550,KH560,KH570)对此多孔硅薄膜进行表面处理,采用红外光谱(FTIR)技术研究了三种硅烷偶联剂对多孔硅处理前后红外光谱的变化。结果显示,三种硅烷偶联剂均大大降低了多孔硅表面的Si—Hx键的数量,使不稳定的Si—H键转化成更加稳定的Si—OR键。其中KH550和KH570消除悬挂键的效果优于KH560。     

半导体桥对含能材料的点火特性研究

在10μF钽电容放电激励下,对两种阻值相当质量不同的半导体桥(SCB)和细化的发火药剂斯蒂芬酸铅(LTNR)和叠氮化铅(PbN6)所组成的发火件进行了实验研究,根据发火件的电特性变化和发火现象发现半导体桥存在电热发火、电爆发火和等离子体发火三种情况,测试了SCB/LTNR和SCB/PbN6发火件的50%发火电压和发火时间。结果表明半导体桥的发火电压阈值不仅与发火药剂有关,还与半导体桥换能元有关,所以半导体桥的设计存在最佳质量,通过对比得知LTNR比PbN6感度高,PbN6比LTNR的燃速高。     

变截面深侵彻弹体结构分析

侵彻弹加强筋结构可以提高弹体抗压、抗弯能力,但不能改善弹体内壁应力集中现象。文中利用有限元软件AUTODYN-2D模拟实际速度侵彻混凝土靶的过程,分析了变截面结构,并与圆筒结构、加强筋结构进行比较。结果表明,在深侵彻过程中,与其它结构相比变截面结构不仅减少了弹体轴向压缩量,并改善了弹体横截面应力集中现象,从而能有效保障弹体结构的稳定性,提高内部装药的安全性。     

恢复系数对弹丸膛内运动参数的影响

弹丸膛内运动过程中,将其前定心部和膛壁碰撞的恢复系数看成定值,不能真实反映弹丸运动过程。实际上,恢复系数是随前定心部撞击膛壁的速度而变化的。通过对弹炮模型简化成的单球碰撞系统进行有限元仿真,得到恢复系数随前定心部径向速度变化的函数关系。将上述关系应用于弹丸膛内运动的数学模型,计算结果与测量结果基本一致,因此考虑恢复系数的变化具有一定的合理性。     

地表超高渣堆对井下巷道稳定性的影响研究

The continuous growth of the height of the coal mine surface slag heap will make the stress size and distribution characteristics of the surrounding rock of the underground roadway under it change significantly, which will seriously lead to large deformation or damage of the roadway, and affect the safe and efficient production of the mine. Based on the geological occurrence conditions of coal strata, mining production and the actual situation of surface super-high slag pile in Wuhushan Coal Mine, a threedimensional model of surface slag pile and underground mining face in Wuhushan Coal Mine is established. The characteristic parameters of roadway surrounding rock stress peak value and location, mining influence range under different slag pile heights have been simulated and calculated, and then the influence law of different slag pile height on roadway stability is analyzed. Combined with the measured data of roadway deformation, the safety critical height of the surface slag pile is initially determined. The research results have important reference value for the safe and efficient production of similar mines.     

RH强制脱碳与自然脱碳工艺生产IF钢精炼效果分析

西昌钢钒厂由于转炉热量不足而以转炉—LF精炼—RH精炼—连铸工艺生产IF钢,为探究RH强制脱碳与自然脱碳工艺生产IF钢精炼效果,采用生产数据统计、氧氮分析、夹杂物自动扫描、扫描电镜和能谱分析等手段,对不同脱碳工艺对顶渣氧化性以及钢的洁净度影响进行了详细研究。结果表明:（1）与自然脱碳工艺炉次相比,采用强制脱碳工艺的炉次在转炉结束与RH进站钢中的平均[O]含量更低;（2）两种工艺脱碳结束钢中的[O]含量基本在同一水平;（3）强制脱碳工艺的炉次在RH结束时渣中平均T.Fe的质量分数降低了1.3%。在能满足RH脱碳效果的前提下,尽量提高转炉终点钢液碳含量、降低钢液氧含量,后续在RH精炼时采用强制吹氧脱碳工艺,适当增大吹氧量来弥补钢中氧,可显著降低IF钢顶渣氧化性。自然脱碳工艺与强制脱碳工艺控制热轧板T.O含量均比较理想;与自然脱碳工艺相比,强制脱碳工艺可有效降低IF钢[N]含量,这与强制脱碳工艺真空室内碳氧反应更剧烈所导致的CO气泡更多和气液反应面积更大有关。脱碳工艺对IF钢热轧板中夹杂物类型、尺寸及数量没有明显影响,夹杂物主要由Al₂O₃夹杂、Al₂O₃–TiO_x夹杂与其他类夹杂物组成,以夹杂物的等效圆直径表示夹杂物尺寸,以上三类夹杂物平均尺寸分别为4.5、4.4和6.5 μm,且钢中尺寸在8 μm以下的夹杂物数量占比高于75%。在RH精炼过程中,尽量降低RH脱碳结束钢中[O]含量,有利于提高钢液洁净度。      

硅烷自组装膜对制备于多孔性基底上导电聚吡咯薄膜性能的影响

采用硅烷偶联剂对在多孔性绝缘Al2O3膜基底上形成的导电聚吡咯(polypyrrole, PPy)薄膜的形貌及导电性能进行了改善,并探讨了硅烷自组装膜与导电PPy薄膜的形成机理.用硅烷偶联剂对Al2O3膜表面进行改性后,形成了与基底牢固结合的硅烷自组装膜,然后通过化学聚合法在自组装膜上制备得到了均匀致密的PPy薄膜.结果表明:硅烷偶联剂有效地改善了PPy薄膜的均匀性及其与基底的附着性,电导率从5.4S/cm提高到了16.6S/cm.     

碳气凝胶的制备及其电除盐性能的研究

在常压条件下通过溶胶-凝胶法和碳化、活化工艺制备碳气凝胶材料.用SEM和BET比表面积测量等手段对材料的表面形貌和微观结构进行分析表征,通过循环伏安法对材料的电化学性能进行研究.联系材料的微观结构和电化学性能,对碳气凝胶的电除盐过程和除盐机理进行了研究和分析,发现碳气凝胶是一种具有很大应用潜力的多孔电极吸附材料.     

Arc-Discharge Synthesis and Microstructure Characterization of AlN Nanowires

AIN nanowires with a hexagonal structure were synthesized using an improved arc-discharge method and their microstructures were characterized using a high-resolution transmission electron microscope. The synthesized AIN nanowires were of various shapes. Their diameters ranged from 20 to 110 nm and the lengths were up to 20μm. Most of the AIN nanowires were coated by an amorphous layer of aluminum oxide. Fabrication yield was about several grams. The growth mechanism was considered to be a vapor-liquid-solid process and an Al droplet formed on the top of as-grown AIN nanowire played a role of catalyst.     

Nano ZrO2 Particulate-reinforced Lead-Free Solder Composite

A lead-free solder composite was prepared by adding ZrO2 nanopowders in eutectic Sn-Ag alloy. Microstrucrural features and microhardness properties of those solders with different ZrO2 nanopowder fraction were examined. Results indicate that the addition of ZrO2 nanopowders reduced the size of β-Sn grains and restrained the formation of bulk Ag3Sn intermetallic compounds （IMCs） due to the adsorption effect of the ZrO2 particles. The Vicker＇s hardness of the obtained lead-free solder composites fits well with the HalI-Petch relationship. The refinement of β-Sn grains favors to improve the microhardness of composite solders.