Bi2O3修饰的BiPO4纳米棒复合催化剂可见光光催化性能的研究

以Bi₂S₃纳米棒为模板合成了形貌可控的BiPO₄ 纳米棒复合光催化剂。在可见光辐射下, 该复合催化剂表现出优异的光催化降解亚甲基蓝(MB)的性能。UV-Vis漫反射谱结果表明: 催化剂经过Bi₂O₃修饰后对可见光有很好吸收; X射线衍射仪和透射电镜等表征结果表明, 所制备的BiPO₄ 纳米催化剂为直径约30 nm、长约200~500 nm的纳米棒。表面修饰少量Bi₂O₃可明显促进光催化剂对亚甲基蓝(MB)的可见光降解效率, 其活性是未修饰催化剂的1.7倍。光电流和N₂吸附实验也表明表面修饰后的催化剂光电流和BET比表面积都明显增加。这可能是由于表面修饰的Bi₂O₃不仅显著提高了BiPO₄ 纳米棒复合催化剂的可见光吸收, 而且在BiPO₄表面起到了富集电子和传输电子的作用。结果表明表面修饰Bi₂O₃的BiPO₄ 纳米棒是一种高活性的光催化材料。     

Blue PL and EL emissions from Bi-activated binary oxide thin-film phosphors

The photoluminescent (PL) and electroluminescent (EL) characteristics in the thin films of various Bi-activated binary oxide phosphors have been investigated. La₂O₃:Bi, Gd₂O₃:Bi and Y₂O₃:Bi phosphor thin films were prepared on thick BaTiO₃ ceramic sheet substrates by r.f. magnetron sputtering depositions followed by postannealing. Intense blue PL emissions were observed from all Bi-activated binary oxide phosphor thin films postannealed at a high temperature. Blue, whitish blue-green or blue-green emissions were observed from thin-film electroluminescent (TFEL) devices fabricated with a La₂O₃:Bi, a Gd₂O₃:Bi or a Y₂O₃:Bi thin-film emitting layer, respectively. In addition, high luminance with good color purity in blue EL was obtained in a TFEL device using a La₂O₃:Bi thin film prepared under optimized conditions.     

鼓风炉法处理铅渣的实践

介绍鼓风炉法处理铅渣的原理、生产工艺流程、设备及主要技术经济指标和生产常见故障及其排除方法。     

镉掺杂Bi2VO5．5的结构、相变、电导性能的研究

通过X射线衍射，DSC和交流阻抗等测试方法研究了镉掺杂Bi2VO55的结构，相变和电性能。由于Cd^2＋的半径与V^5＋和Bi^3＋的半径都比较接近，所以在合成BICDVOX体系时假设了两种模型：Bi2V1-xCd，O5.5-3/2x（x=0．05，0．075，0．10，0．125，0．15）和Bi2-xVCdxO5．5-1／2x（x=0．10，0．20）。XRD和DSC分析表明了这两种模型可能同时存在。根据交流阻抗谱的结果，当x=0．10时，具有较高的电导率，这归因于此成分使高电导的四方相可以稳定到室温。     

石墨炉原子吸收光谱法测定纯铜中的痕量铅和铋

为控制纯铜中杂质元素的指标,准确测定其中痕量元素铅和铋的含量十分必要。采用铜作为基体改进剂,可提高灰化温度和原子化温度。选择纯铜样品进行试验测定铅和铋的相对标准偏差分别为6.32%和3.53%。石墨炉原子吸收光谱法测定纯铜中痕量铅和铋,方法可靠,简单快速。     

Bi3.25La0.75Ti3O12纳米管的制备工艺研究

研究了一种Bi3.25La0.75Ti3O12 (BLT)铁电存储材料纳米管的简单有效合成方法。通过阳极氧化铝模板(AAO)辅助溶胶凝胶法,合成了BLT纳米管。其基本过程是以次硝酸铋、硝酸镧和钛酸四丁酯为原料,以冰醋酸和乙二醇甲醚为溶剂配制BLT溶胶,然后将BLT溶胶滴在AAO模板表面,浸润后烘干并反复多次,而后将材料在500 ℃下保温1 h,除去有机物,最后在750 ℃下保温30 min晶化,用KOH腐蚀去除氧化铝模板,即得到BLT纳米管。结果表明,BLT纳米管具有[117]择优取向;BLT纳米管管壁光滑,直径与模板孔径相当,约300 nm,且分布均匀,管壁厚度约25 nm,纳米管是多晶体,由粒径为8~12 nm晶粒组成     

Ion Implantation into Fullerene

Abstract

Various elements - H, Li, B, Ar, Kr, Xe, Cs, Pb and Bi - have been implanted at 20 - 200 keV and at room temperature up to different fluences into thin fullerene layers evaporated onto polished Si substrates. Subsequently their depth profiles were determined by NRA, NDP, or RBS analysis. These measurements were compared with ion implantation into amorphous carbon and with theory. In most cases the degree of fullerene destruction was monitored by Raman spectroscopy earlier.

The results show that there exists a general trend insofar as theory appears to underestimate both ranges and range stragglings for heavy projectile ions, whereas for light and medium-heavy ions experimental range results agree with theory within some 30%. In a few cases range stragglings are found to be considerably larger than predicted by theory, which may be attributed to post-implantational radiation enhanced diffusion. There is only little influence of the degree of fullerene destruction onto the implantation profile parameters. Ranges in amorphous carbon appear to be in general a little bit larger than those ones in fullerene.     

Layered bismuth oxide/bismuth sulfide supported on carrageenan derived carbon for efficient carbon dioxide electroreduction to formate

Electrochemical reduction of carbon dioxide (CO₂ER) into formate plays a crucial role in CO₂ conversion and utilization. However, it still faces the problems of high overpotential and poor catalytic stability. Herein, we report a hybrid CO₂ER electrocatalyst composed of layered bismuth sulfide (Bi₂S₃) and bismuth oxide (Bi₂O₃) supported on carrageenan derived carbon (Bi-CDC) prepared by a combined pyrolysis with hydrothermal treatment. In such 3D hybrid, layered Bi₂O₃ and Bi₂S₃ are uniformly grown on nanocarbon supports. Benefiting from strong synergistic effect between Bi₂O₃/Bi₂S₃ and nanocarbon, Bi-CDC-1:2 displays a high Faradic efficiency (FE) of >80% for formate production in the range of -0.9 V to -1.1 V with the maximum formate FE of 85.6% and current density of 14.1 mA·cm^-2 at -1.0 V. Further, a positive onset potential of -0.5 V, a low Tafel slope of 112.38 mV·dec^-1, and a slight performance loss during long-term CO₂ER tests are observed on Bi-CDC-1:2. Experimental results shows that the better CO₂ER performance of Bi-CDC-1:2 than that of Bi₂O₃ can be attributed to the strong interfacial interactions between nanocarbons and Bi₂O₃/Bi₂S₃. In situ ATR-FTIR measurements reveal that the rate-determining step in the CO₂ER is the formation of HCOO* intermediated. Compared with carbon support, Bi-CDC-1:2 can promote the production of HCOO* intermediate and thus promoting CO₂ER kinetic.     

双轴向经编针织复合材料的弹道侵彻破坏

通过真空辅助树脂传递模压法（VARTM）制造双轴向经编针织复合材料。在350～750m/s冲击速度范围内对复合材料作弹道冲击测试,得到弹体的入射速度、剩余速度及动能损失,弹体的剩余速度与入射速发近似满足线性关系,动能损失随弹速的增加呈现先上升后下降的状态。考察复合材料靶体的弹道侵彻破坏损伤形态,发现复合材料受弹面的破坏区域较子弹出射面的破坏区域小且破坏形态不同,由此揭示双轴向经编针织复合材料的弹道侵彻破坏模式与机理。     

Bi0.5Na0.5TiO3基A位多重复合无铅压电陶瓷的研制

针对钛酸铋钠(Bi0．5Na0．5TiO3)基复合钙钛矿压电铁电材料,发明了多种新的AB03型A位多重复合无铅压电陶瓷体系。这些新的无铅压电陶瓷具有压电铁电性能优良、铁电电滞回线矩形度高、压电铁电性能的温度特性好、工艺稳定性和重复性好等特点。所测得的一个体系(Bi0．5(Na1-x-yKxLiy)0．5TiO3)的d33达230pC／N,其kp达0．40,Pr达40μC/cm^2,矫顽场Ec则较低(小于4kV／mm);变温铁电电滞回线测试表明,在温度接近200℃时,该陶瓷还具有很好的铁电电滞回线。该体系无铅压电陶瓷性能优异,工艺性好,具有实用性。