SiO2-Al2O3-PbF2-ZnF2-ErF3玻璃陶瓷的显微结构

氟氧化物玻璃陶瓷综合了传统激光晶体和激光玻璃的优点，是近年来激光材料研究的新热点。我们制备了掺杂Er离子的SiO2-Al2O3-PbF2-ZnF2玻璃陶瓷材料，并对其显微结构进行了初步研究。     

钙铝硼硅玻璃/氧化铝复合材料性能研究

通过高温熔融法制备的CaO-Al2O3-B2O3-SiO2玻璃粉末与α-Al2O3粉末按照质量分数50:50混合,烧结制备了钙铝硼硅玻璃/氧化铝系低温共烧陶瓷材料,研究了烧结温度对复合材料的物相组成、微观结构、力学性能及介电性能的影响.结果表明,875℃烧结制备的复合材料性能最佳,抗弯强度为164 MPa,介电常数为7.8,介电损耗为0.001 3,热膨胀系数为5.7×10-6/℃,具有良好的综合性能,可用作低温共烧陶瓷基板材料.     

Bi2O3对Al2O3-ZnO-Bi2O3-B2O3低熔玻璃结构和性能的影响

采用传统的熔淬技术制得了低熔Al2O3-ZnO-Bi2O3-B2O3玻璃,研究了玻璃结构、玻璃特征温度、线膨胀系数(α1)以及密度随Bi2O3含量的变化关系.结果表明:随着Bi2O3含量的增加,玻璃网络中[BO4]取代了部分[BO3],玻璃网络中出现Bi-O结构,玻璃中非桥氧的数量也逐渐增多;软化温度(ts)、玻璃化温度(tg)都是先上升后下降,而线膨胀系数先减小后逐渐增大,玻璃密度先是线性增加,然后增加趋势变大.     

Er3 /Yb3 共掺TeO2-WO3-Bi2O3玻璃的光谱性质

用高温熔融法制备了Er3+/Yb3+共掺的TeO2-WO3-Bi2O3玻璃,研究了该玻璃的吸收和荧光光谱性质.应用Judd-Ofelt(JO)理论计算了Er3+的谱线强度、自发辐射跃迁几率、荧光分支比和辐射寿命等光谱参数,并拟合了相应的强度参数Ωt(t＝2,4,6).Er3+在该玻璃中4I13/2→4I15/2发射的荧光半高宽(FWHM)为77nm,应用McCumber理论计算的受激发射截面为1.03×10-20cm2.其带宽特性FWHM×σpeake乘积优于掺Er3+的硅酸盐、磷酸盐和铋酸盐玻璃,说明这是一种制备宽带光纤放大器的优良基质材料.Er3+在400～850nm波长范围存在着5个上转换发射峰,分别对应Er3+的激发态4I7/2、2H11/2、4S3/2、4F9/2和4I9/2到基态4I15/2的发射,分析了其可能存在的上转换过程.     

Tm3 掺Li2O-CdO-Al2O3-SiO2玻璃的发光特性研究

通过高温熔融方法合成了Tm^3＋掺Li2O-CdO-Al2O3-SiO2（LCAS：Tm^3＋）氧化物理论，并对其高温热处理和淬火获得一种新型玻璃材料，测量和分析了该材料吸收、激发与发射光谱。高达95％以上近红外透过率表明，LCAS：Tm^3＋玻璃可作为近红外波段高透过率光学玻璃；远大于10^-18cm的积分发射截面、较高的荧光分支比与能形成粒子数反转的荧光寿命表明，LCAS：Tm^3＋玻璃可能成为一种新的激光功能材料。通过淬火获得样品，其发射光谱在400～680nm新生较强的大宽带，且随掺杂浓度的增加而发生蓝移，预示该材料可应用于光存储和全色显示领域，对此原因进行了分析与讨论。     

BaO Nd2O3 Sm2O3 TiO2薄膜的微波特性

在制作完底电极的LaAlO3(100)衬底上,利用磁控溅射法制备了一层BaO-Nd2O3-Sm2O3-TiO2(BNST)系薄膜,再对薄膜进行退火处理.X线衍射仪(XRD)分析表明,经退火处理的BNST薄膜结晶效果良好.采用薄膜电容结构来实现电容的测量,主要研究了BNST薄膜电容的频率特性.阻抗分析测试和矢量网络分析测试表明,在测试频率为1 MHz时,介电常数为58.3,介电损耗小于2％;在1 GHz的测试频率下,介电常数为57.5,介电损耗小于3％.研究表明,制备的BNST薄膜的频率特性稳定,基本满足微波频率下使用的要求.     

Er3+掺杂Bi2O3-B2O3-Ga2O3玻璃光谱性质及热稳定性研究

用高温熔融法制备了Er3 掺杂50Bi2O3-(50-x)B2O3-xGa2O3(x=0,4,8,12,15 mol%)系列玻璃,测试了上述玻璃样品的吸收光谱、荧光光谱、荧光寿命及热稳定性.分别应用Judd-Ofelt理论和McCumber理论计算了Er3 强度参数和受激发射截面.研究发现,当Ga2O3含量在mol 8%时,荧光半高宽(FWHM)、峰值发射截面(σpeak e)和4I13/2能级荧光寿命(τm)均达到了峰值,其FWHM和σpeake分别为81 nm和1.03×10-20cm2.热稳定性则随着Ga2O3含量的增加而改善,析晶开始温度(Tx)和玻璃转变温度(Tg)之间的差值(△T)最高达到了261℃.研究表明,含适当重金属Ga2O3的铋硼酸盐玻璃具有较好的光学性能和热稳定性,适合于作为高增益、低噪声的宽带掺铒光纤放大器的基质材料.     

2—3混值电路中的3B—2T编码技术＊

本文通过对2-3混值电路中信号编码效率与冗余度的讨论,分析了传统的1T-2B编码的缺点,提出了3B-2T编码方案,设计了用于3B-2T编码的CMOS接口电路。讨论表明,利用该编码的电路具有效率高,设计容易,并能在不增加电路内部连线的前提下减少三分之一的外部信号线等优点。     

Bi_2O_3含量对ZnO-BaO-Bi_2O_3-B_2O_3系玻璃性能的影响

用熔融冷却方法制备了ZnO-BaO-Bi2O3-B2O3系低熔点玻璃,研究了Bi2O3含量对所制玻璃热学性能和体积电阻率的影响。结果表明:随着Bi2O3含量的增大,所制玻璃密度和线膨胀系数增大,而膨胀转变温度(tg)、膨胀软化温度(tf)和体积电阻率(ρv)减小;当Bi2O3摩尔分数为0～12%时,随着Bi2O3含量增大,玻璃的tg、tf和ρv显著降低;而当Bi2O3摩尔分数为12%～25%时,这种变化趋势明显减弱。     

Er3+/Yb3+共掺Bi2O3-GeO2-Na2O玻璃的上转换发光

研究了不同Er3 /Yb3 掺杂比46Bi2O3-44GeO2-10Na2O(B46G44N10)(摩尔分数)玻璃的吸收光谱、红外吸收谱和上转换光谱性质,分析了玻璃中Yb3 敏化Er3 的上转换发光机制。测试了Er3 离子在不同Yb3 浓度下玻璃中的上转换荧光强度,得到最佳的掺杂质量比Er3 ∶Yb3 =1∶6。计算了在980 nm激发下Er2O3质量分数为0.5%和Yb2O3质量分数为3.0%的Er3 /Yb3 共掺B46G44N10玻璃的绿光上转换效率为2.27×10-4。比较了不同基质材料玻璃的上转换效率,结果表明B46G44N10玻璃是一种良好的上转换基质材料。     

MgF_2·SrF_2掺杂PZN－BT陶瓷

适量掺入ＭｇＦ_２·ＳｒＦ_２有效地降低了０．８５ＰＺＮ（Ｐｂ（Ｚｎ_（１／３）Ｎｂ_（２／３））Ｏ_３）－０．１５ＢＴ（ＢａＴｉＯ_３）材料的烧结温度并得到了介电常数－温度特性接近于Ｘ７Ｒ特性标准的瓷料。在很宽的温度范围内出现了双介电常数峰。这种现象可从材料的纳米结构出发，用超顺电态的概念来描述。     

High-Quality$hboxAl_2hboxO_3/hboxPr_2hboxO_3/hboxAl_2hboxO_3$MIM Capacitors for RF Applications

The electrical characteristics of layered$hboxAl_2hboxO_3/hboxPr_2hboxO_3/hboxAl_2hboxO_3$metal–insulator–metal (MIM) capacitors for RF device applications are presented for the first time. This advanced dielectric layer system 4-nm$hboxAl_2hboxO_3/hbox8-nm hboxPr_2hboxO_3/hbox4-nm hboxAl_2hboxO_3$shows a high capacitance density of 5.7$hboxfF/muhboxm^2$, a low leakage current density of$hbox5 times hbox10^-9 hboxA/hboxcm^2$at 1 V, and an excellent dielectric loss behavior over the studied frequency range.     

Some properties of Cu2SnSe3, Cu2GeSe3 and other A 2 I BIVC 3 VI compounds

Attempts were made to synthesize nine A₂ ^IB^IVC₃ ^VIcompounds (A^I = Cu,Ag; B^IV = Ge,Sn,Pb; C^VI = Se,Te) by solidification from stoichiometric melts. Ternary phases were obtained for four of the five combinations involving Cu. Ingots of Cu₂SnSe₃ and Cu₂GeSe₃ were essentially single-phase, indicating that these compounds are congruently melting. The Cu₂GeTe₃ ingot contained a small percentage of GeTe, while the ternary phase made up only about half the Cu₂SnTe₃. No ternary phase was detected for Cu₂PbSe₃ or for any of the four combinations involving Ag. The electrical resistivity and Hall coefficient have been measured down to 77 K in Cu₂SnSe₃ and Cu₂GeSe₃, and the temperature dependence indicates the presence of two band conduction. Both undoped compounds were p-type with room temperature carrier concentrations greater than 1×10¹⁸/cm³. Doping Cu₂SnSe₃ with I, Sb, In or Zn resulted in hole concentrations greater than 10²⁰/cm³. The optical absorption edge occurs at 0.5 eV for Cu₂SnSe₃ and at 0.85 eV for Cu₂GeSe₃.     

K_2O-B_2O_3-SiO_2/Al_2O_3 LTCC复合基板材料性能研究

采用K2O-B2O3-SiO2玻璃与Al2O3复合烧结,制备了K2O-B2O3-SiO2/Al2O3低温共烧陶瓷(LTCC)复合基板材料,研究了不同组分含量对体系微观结构和性能的影响。结果表明,复合基板材料的相对介电常数εr和介质损耗均随着Al2O3含量的增加而增加,当Al2O3质量分数为45%时,复合基板材料的介质损耗为0.0085,εr为4.55(1MHz)。抗弯强度可达到160MPa。     

New FIR laser lines from optically pumped C2H3F,C2H3Cl,C2H3Br,C2H3CN,C2H5F,CH2CF2, HCOOH and CH3Br

Twenty-seven new cw far infrared laser lines with wavelengths between 137 and 988Μm have been observed from optically pumping C₂H₃F, C₂H₃Cl, C₂H₃Br, C₂H₅F, C₂H₃CN, CH₂CF₂, HCOOH and CH₃Br with a CO₂ laser. The wavelengths of these FIR laser lines were determined together with their optimum pressures and relative intensities.     

Lorenz Function of Bi2Te3/Sb2Te3 Superlattices

Combining first-principles density functional theory and semiclassical Boltzmann transport, the anisotropic Lorenz function was studied for thermoelectric Bi₂Te₃/Sb₂Te₃ superlattices and their bulk constituents. It was found that, already for the bulk materials Bi₂Te₃ and Sb₂Te₃, the Lorenz function is not a clear function of charge carrier concentration and temperature. For electron-doped Bi₂Te₃/Sb₂Te₃ superlattices, large oscillatory deviations of the Lorenz function from the metallic limit were found even at high charge carrier concentrations. The latter can be referred to quantum well effects, which occur at distinct superlattice periods.     

Fe_2O_3对Bi_2O_3-B_2O_3-ZnO系统封接玻璃结构及性能的影响

采用熔融冷却的方法制备了(40–x)Bi_2O_3-30B_2O_3-30Zn O-x Fe_2O_3(0≤x≤10)系统玻璃。研究了Fe_2O_3取代Bi_2O_3对Bi_2O_3-B_2O_3-Zn O系统玻璃结构、玻璃化转变温度(t_g)、初始析晶温度(t_c)、热稳定性、热膨胀系数(α)及化学稳定性的影响。红外光谱(FTIR)结果表明,Fe2O3以网络修饰体存在于玻璃结构间隙,增强了玻璃结构,玻璃密度减小。随着Fe_2O_3含量的增加,t_g、t_c逐渐升高,玻璃的热稳定性有所降低。α从8.2×10~(–6)℃~(–1)减小至7.4×10~(–6)℃~(–1),玻璃的软化点(t_s)逐渐从439℃升高到486℃。引入Fe_2O_3后,玻璃的化学稳定性提高。     

In-situ monitoring of the growth of Bi2 Te2 and Sb2 Te3 films and Bi2 Te3-Sb2 Te3 superlattice using spectroscopic ellipsometry

In this work, we present in-situ monitoring of the growth of bismuth telluride (Bi₂Te₃) and antimony telluride (Sb₂Te₃) thin films as well as Bi₂ Te₃-Sb₂Te₃ superlattice using a spectroscopic ellipsometer (SE). Bi₂Te₃ and Sb₂ Te₃ films were grown by metalorganic chemical vapor deposition (MOCVD) at 350 C. A44-wavelength ellipsometer with spectral range from 404 nm to 740 nm was used in this work. The optical constants of Bi₂ Te₃ and Sb₂Te₃ at growth temperature were determined by fitting a model to the extracted in-situ SE data of optically thick Bi₂ Te₃ and Sb₂ Te₃ films. Compared to the optical constants of Bi₂ Te₃ and Sb₂ Te₃ at room temperature, significant temperature dependence was observed. Using their optical constants at growth temperature, the in-situ growth of Bi₂ Te₃ and Sb₂ Te₃ thin films were modeled and excellent fit between the experimental data and data generated from the best-fit model was obtained. In-situ growth of different Bi₂ Te₃-Sb₂ Te₃ superlattices was also monitored and modeled. The growth of Bi₂ Te₃ and Sb₂ Te₃ layers can be seen clearly in in-situ SE data. Modeling of in-situ superlattice growth shows perfect superlattice growth with an abrupt interface between the two constituent films.