纳米掺锑氧化锡粉末的制备及表征

以 SnCl4·5H2O和SbCl3乙醇溶液为原料,采用离子交换除氯水解法得到无氯离子的掺锑氢氧化锡胶体沉淀,以正丁醇作脱水剂对胶体进行共沸干燥处理,所得的掺锑氢氧化锡干微粉经热处理后得到了四方形金红石结构的掺锑氧化锡纳米粉末.用TG-DTA、IR、BET、BJH、XRD、TEM等方法对粉体的结构、物相、形貌进行了表征.     

Preparation of highly dispersed antimony-doped tin oxide nanopowders by azeotropic drying with isoamyl acetate

Antimony-doped tin hydroxide colloid precipitates were prepared by hydrolysis of SnCl4·5H2O and SbCl3 ethanol solutions. Isoamyl acetate was selected as azeotropic drying solvent and was compared with the most commonly used n-butanol solvent on treating precipitate for low hard agglomeration precursor powders. The FT-IR, BET, XRD, and TEM results of the precursor powders and calcinated antimony-doped tin oxide powders were recorded. The results demonstrate that isoamyl acetate is an excellent azeotropic drying solvent that can effectively prevent the agglomeration of particles and greatly improve the fluffiness of the obtained dried powders. After these precursor powders are calcined, antimony-doped tin oxide nanopowders with tetragonal futile structure and high dispersivity can be obtained.     

轴承故障对提升机天轮系统响应特性影响

根据Lagrange方程建立了天轮系统的动力学模型,理论上分析了轴承正常和故障时天轮系统的响应特性。为了验证理论模型的正确性,根据提升机天轮工作原理搭建了模拟提升机的实验台,分别测试了轴承正常、轴承故障时的振动信号,实验结果和理论结果基本一致,验证了理论模型的正确性。通过理论和实验分析可知,轴承故障时产生的冲击振动会传递给天轮及其连接部件,使天轮系统出现周期性振动,从而加剧提升系统运行过程中的振动,导致钢丝绳动张力变大。     

某大桥桥型方案比选

通过对几种大跨度桥梁结构体系受力特点及适用条件的分析比较,并结合某大桥所处的地理位置、通航要求、周围环境等实际情况,提出了拱桥、斜拉桥和悬索桥3种桥型方案,并通过对上述3种桥型方案在造价、施工难度、工期、景观等多方面对比分析,确定了下承式简支钢箱拱桥的桥型方案,对类似工程桥型方案的比选有一定的借鉴作用。     

来自生活的DV灵感

如何能拍摄出一部优秀的DV作品，并且能获得业内大奖，这是许多DV发烧友梦寐以求的事。多看，多学是一条有用的途径。不过，与其向大师求教，不如借鉴身边同龄人的经验。看过杨芬的创作过程，大家是不是有了更多的灵感?     

高效液相色谱法测定牛组织中雷复尼特的残留量

采用高效液相色谱法测定牛组织中雷复尼特的残留量。牛组织样品经乙腈提取,中性氧化铝柱净化后采用Kromasil C18柱,以v(乙腈)∶v(pH2.5的水)=83∶17为流动相,紫外检测波长282nm处检测雷复尼特。在0.05～4.0μg/mL内线性关系良好,检测低限为0.01μg/g。高、中、低3个水平添加时肌肉组织中样品的平均回收率分别为78.3%,85.8%和95.1%;肝组织中样品的平均回收率分别为73.3%,83.9%和91.9%;肾组织中样品的平均回收率分别为74.3%、81.9%和92.8%。测试方法快速、简便、准确、灵敏,可用于牛组织中雷复尼特残留量的测定。     

利用HPLC-MS/MS技术进行羟自由基检测的分析方法研究

Hydroxyl radical (•OH) can cause severe damage to cells and tissues. However, its analysis is very difficult for its high reactivity and very short life. This paper present a HPLC-MS/MS method for indirectly detecting •OH by determining DMPO-OH, its addut with spin trap DMPO ( 5,5-dimethyl-1-pyrroline N-oxide ), with the N-Methyl-2-Pyrrolidone (NMP) used as internal standard. The ratio of the peak area of the DMPO-OH and NMP negatively correlate with the concentration of •OH. The results show that the method is simple, rapid, precise in both the determination of •OH and evaluation of •OH scavenging activities of antioxidants.     

糖精钠和硫酸铈对电解厚镍始极片性能的影响

采用X-射线衍射和电化学测量法研究糖精钠和硫酸铈两种添加剂对电镀镍始极片的晶面取向、晶粒大小以及耐蚀性的影响。结果表明,在镀镍溶液中加入糖精钠或硫酸铈对镀层晶面取向、晶粒大小均有影响,晶面取向都呈现(200)择优,且晶粒都更细小。镀层的极化曲线显示糖精钠和硫酸铈都能使其自腐蚀电位更负,而对其腐蚀速率都有减缓作用,厚镍始极片作为电镀阳极时有利于电极的均匀溶解。