近紫外激发具有颜色可调的Er^(3+)/Eu^(3+)共掺BiOCl荧光粉

本文采用固相法在500℃合成了Er^(3+)/Eu^(3+)共掺BiOCl荧光粉,并通过XRD,SEM,吸收,激发和发射光谱研究了其结构、形貌和发光特性.XRD和SEM结果表明在500℃下即可成功合成纯四方相片层结构的Er^(3+)/Eu^(3+)共掺BiOCl荧光粉.吸收光谱表明掺杂Er^(3+)/Eu^(3+)离子使BiOCl形成杂质能级;激发光谱显示该荧光粉具有来自于基质BiOCl价带(VB)到导带(CB)跃迁的优异宽带近紫外激发特性.在380 nm近紫外光激发下,同时获得了Er^(3+)离子和Eu^(3+)离子的特征发射峰,其中发光中心位于410 nm(~2H_(9/2)→~4I_(15/2)),525 nm(~2H_(11/2)→~4I_(15/2)),554 nm(~4S_(3/2)→~4I_(15/2)),673 nm(~4F_(9/2)→~4I_(15/2))的发射峰来自于Er^(3+)离子的跃迁,而581 nm(~5D_0→~7F_0),594 nm(~5D_0→~7F_1),622 nm(~5D_0→~7F_2),653 nm(~5D_0→~7F_3),699 nm(~5D_0→~7F_4)的发射峰则来自于Eu^(3+)离子的跃迁.值得注意的是,与传统Er^(3+)/Eu^(3+)掺杂的材料不同,该荧光粉还具有独特高效的紫光(Er^(3+))和长波红光(Eu^(3+))发射特性,分析表明这与BiOCl的结构有关;并且通过改变掺杂浓度,实现了发光颜色由黄绿光→黄光→橙红光的调节.研究结果表明Er^(3+)/Eu^(3+)共掺BiOCl荧光粉有望成为一种潜在的近紫外激发白光LED荧光粉.

掺Bi石英光纤的γ射线辐照和温度影响特性

采用改进的化学气相沉积法制备了尺寸为10/130μm的掺Bi单包层石英光纤,把光纤分成若干组之后置于不同剂量的60Coγ辐射源下辐照,测试了光纤在辐照前后的吸收谱和荧光谱,并测试了光纤在全温度范围(-40—70?C)下荧光强度的变化.实验结果表明,辐照后700,800 nm处的吸收峰显著增强,这是由于辐照导致更多Bi近红外活性中心的生成.976 nm光抽运不同剂量辐照后的光纤,中心位于1230 nm的荧光谱没有明显变化,验证了掺Bi石英光纤用于太空及辐照环境下光通信的可能性.在全温度范围内,分析了荧光强度的变化规律,为今后掺Bi光纤激光器的稳定工作提供了数据基础.

高灵敏度光纤电流传感器用掺Bi磁性石榴石薄膜

本文介绍了用于高压大电流测量的高灵敏度光纤电流传感器中使用的掺Bi磁光磁性石榴石薄膜的基本特性,获得高温度稳定性弗尔德常数Ve的分析方法以及掺Bi磁性石榴石薄膜的液相外延生长方法。

压力对掺Bi的LaCaMnO中晶格畸变的影响

利用同步辐射X光衍射技术，对（La1-xBix)0.5Ca0.5MnO3(x=0.2,0.3,0.4）中存在的Jahn-Teller畸变，进行了原位的高压研究。实验表明在外加压力的作用下，能有效地影响到晶格中Mn-O键长和Mn-O-Mn键角的变化，样品中的晶格畸变有所减小。并且对在晶格中存在的两种不同的畸变模式Q2和Q3，在外加压力的作用下的变化规律进行了讨论。由于这两种不同的畸变模式在受到外力作用时，表现形为不一样，导致了位于a-b基面上的Q2畸变模式的消失，并且导致Q2畸变模式消失的压力点随掺杂浓度的增加而增加。

双包层掺Bi光纤的制备及其光谱特性研究

用改进的化学气相沉积方法和溶液掺杂方法制备了掺Bi双包层石英基光纤.测试了掺Bi光纤预制棒切片的吸收光谱和掺Bi光纤在特定波长下的吸收系数,在不同波长的激光激发下,研究了掺Bi光纤的近红外荧光光谱.掺Bi光纤在976 nm激光激发下,其荧光光谱范围在1000-1400 nm之间,荧光峰的峰值位于1140 nm附近,半高宽约为130 nm;在793和808 nm激光激发下得到了1000-1700 nm的超宽带近红外荧光,半高宽超过250 nm.通过对掺Bi光纤预制棒切片进行900℃保温1 h的热处理后,发现在808 nm激光激发下预制棒切片的荧光强度增加了近4倍.研究结果表明,具有超宽带荧光特性的双包层掺Bi光纤有望作为超短脉冲激光器和可调谐激光器的增益介质.

辐照对Bi/Er/La共掺有源光纤磁光特性的影响

针对标准单模石英光纤磁光特性弱的特点,利用改进化学气相沉积(modified chemical vapor deposition,MCVD)法结合原子层沉积(atomic layer deposition,ALD)技术制备了Bi/Er/La共掺有源光纤,并且用伽马射线辐照对该光纤进一步处理;搭建了光纤的费尔德常数测试系统,研究辐照前后Bi/Er/La共掺有源光纤的磁光特性。实验结果表明:在波长为1310 nm处,Bi/Er/La共掺有源光纤的费尔德常数(1.02 rad/(T·m))比单模光纤(0.76 rad/(T·m))高约36.2%。经伽马射线辐照后,Bi/Er/La共掺有源光纤的费尔德常数随着辐照剂量的增加而增大,经3.0 kGy剂量处理后,其费尔德常数增加了54.90%,而单模光纤的费尔德常数仅增加了26.3%,且在1.0 kGy辐照处理已达到饱和。

Bi_2O_3对烧结LiZn铁氧体性能的影响

采用氧化物陶瓷工艺制备了掺Bi_2O_3的Li_(0.4)Zn_(0.2)Fe_(2.4)O_4铁氧体.用XRD、SEM、密度测试和磁性能表征,研究了Bi_2O_3对LiZn铁氧体性能的影响.结果表明:Bi_2O_3能有效抑制烧结过程中的锂挥发,促进固相反应,降低烧结温度,但过多的Bi_2O_3会阻止晶粒生长;适量掺杂Bi_2O_3可以提高LiZn铁氧体的饱和磁感应强度和矩形比,降低铁氧体的矫顽力.

掺铁钨酸铋的制备及其超声降解性能测试

为了探究掺铁钨酸铋催化剂的超声催化性能,本实验采用溶剂热法合成了掺铁Bi_2WO_6催化剂,使用X射线衍射、电子能谱和场发射扫描电镜对催化剂的物质结构和形貌进行了表征,研究了该催化剂的超声催化降解性能.以直接大红作为模拟染料废水,考察了催化剂的铁掺杂量、投加量、溶液初始浓度、溶液pH值以及超声功率对染料废水的超声催化降解性能的影响.实验结果表明:当铁的掺杂量为1%,投加量为0.05g(0.2g·L^(-1)),溶液初始浓度为10mg·L^(-1),pH值为6,超声频率为45kHz和超声功率为80%时,直接大红染料废水的超声催化降解率达到最高值90.47%.

Effects of Zn addition on mechanical properties of eutectic Sn-58Bi solder during liquid-state aging

Interfacial reaction, tensile strength and creep resistance of Sn-58Bi-x Zn(x=0, 0.7, mass fraction, %) solder samples during liquid-state aging were investigated. The coarsening of Bi and the growth of Cu-Sn intermetallic compounds(IMCs) in Sn-58Bi-0.7Zn solder sample were both effectively suppressed. With the addition of 0.7% Zn, ultimate tensile strengths(UTSs) of the Sn-58 Bi solder slabs were respectively increased by 6.05% and 5.50% after reflow soldering and liquid-state aging, and those of the Cu/Sn-58Bi/Cu solder joints were also increased by 21.51% and 29.27%, respectively. The increase in strengthening effect of Cu/Sn-58Bi-x Zn/Cu solder joints could be attributed to the fracture surface which was changed from the Cu/IMC interface to the IMC/solder interface due to the finer Bi grain. Nanoindentation results revealed that the creep behavior of Sn-58Bi-0.7Zn solder was significantly improved compared with that of the eutectic Sn-58 Bi solder after reflow soldering and liquid-state aging.

Bi quantum dots implanted 2D C-doped BiOCl nanosheets: Enhanced visible light photocatalysis efficiency and reaction pathway

The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving better solar light conversion and photocatalysis efficiency. For this purpose, we have designed a novel Bi quantum dots(QDs) implanted C-doped BiOCl photocatalyst(C/BOC/B) for NOx removal. The feasibility was firstly evaluated through density functional theory(DFT) calculations methods, which indicates that the enhanced photocatalytic performance could be expected owing to the synergistic effects of doped C heteroatoms and loaded Bi QDs. Then, the C/BOC/B was synthesized via a facile hydrothermal method and exhibited efficient and stable visible light photocatalytic NO removal. The results found that the doped C atoms can serve as electron guides to induce oriented charge transfer from Bi QDs to BiOCl, while the Bi QDs can act as light-capture and electron-donating sites. The reaction pathway and mechanism for NO conversion was unveiled by in situ Fourier-transform infrared spectroscopy combined with DFT calculation. The enhanced adsorption of reactants and intermediates could promote the overall reaction efficiency and selectivity in photocatalytic NO conversion. This work could provide a new perspective on the mechanistic understanding of the synergistic effects toward non-metal doping and SPR effects in semiconductor photocatalysts, and this presented technique could be extended for other semiconductor materials.

Effect of doping Bi on oxygen evolution potential and corrosion behavior of Pb-based anode in zinc electrowinning

A new anodic material of ternary Pb-0.8%Ag-(0-5.0%)Bi alloy for zinc electrowinning was obtained by doping Bi.The anodic oxygen evolution potential,corrosion rate,surface products after polarization,and microstructures before and after polarization were studied and compared with those of Pb-0.8%Ag anode used in industry.The results show the anodic overpotential decreases with the increase of Bi content in the alloys.When the content of Bi is 1.0%(mass fraction),the anodic overpotential is 40-50 mV lower than that of Pb-0.8%Ag anode.While the corrosion rate decreases and then increases with the increase of Bi content.The Pb-0.8%Ag-0.1%Bi anode has the lowest corrosion rate(0.090 6 mg/(h·cm2).Doping Bi influences the structure of the anodic layer,but does not change the phase.The Pb-0.8%Ag-1.0%Bi anode layer is of a more fine-grained structure compared with Pb-0.8%Ag anode.

直流电弧等离子雾化法制备纳米Sn1-xBixO2粉末的研究

采用电弧等离子雾化法制备了不同Bi2O3含量的掺Bi纳米复合SnO2粉末,粉末的粒径在40 nm左右。采用X射线衍射(XRD)、高分辨透射电镜(HR-TEM)分析了粉末的物相结构及形貌,并利用半高宽法(FWEH)计算了粉末的晶粒尺寸。研究表明,采用电弧等离子雾化法制备的掺Bi纳米复合SnO2粉末的主要晶相为四方相SnO2,含有少量焦绿石结构的Bi2Sn2O7相;粉末的晶格常数接近(a≈4.75A,c≈3.19A),沿(110)和(101)晶面生长;粉末的形貌呈类球形,存在少量的柱状晶,晶粒内部存在类似第二相的小颗粒。Bi2O3含量(w)为20%的粉末经过1 320℃处理后,团聚严重,有一定量的Bi2O3析出、偏聚。

Broadband near-infrared luminescence and energy trans-fer in Bi singly-doped and Bi/Yb co-doped titanate glasses

Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated.It is also found that the Bi-related emission intensity can be enhanced by Yb3+co-doping at the excitation of 980 nm LD.It should be ascribed to the energy transfer from Yb3+to active Bi ions.The energy transfer processes are studied based on the Inokuti-Hirayama(I-H)model,and the energy transfer of electric dipole-dipole interaction is confirmed to be dominant in Bi/Yb co-doped glasses.