Yb:YAG晶体的晶胞参量及Yb3+分凝系数的研究

应用提拉法生长出不同Yb³⁺浓度的Yb_3xY_3(1-x)Al₅O₁₂晶体.Yb³⁺离子的分凝系数1是1.08±0.01,与Yb³⁺离子掺杂浓度无关.研究了Yb_3xY_3(1-x)Al₅O₁₂晶体的晶胞参量,推导出联系晶胞参量、密度与Yb³⁺离子掺杂浓度的关系方程式.     

The effect of polymer-substrate interaction on the nucleation property: Comparing study of graphene and hexagonal boron nitride Nanosheets

Hexagonal boron nitride nanosheets (BNNSs) can work as a more efficient nucleating agent for two polyesters compared to graphene. Studies on the crystallization and dewetting processes of two polyesters, poly(butylene succinate) and poly(butylene adipate), on the two substrate surfaces prove that the interaction between BNNSs and the polyesters is stronger than that between graphene and the polyesters. This strong interaction induces the pre-ordered conformation of molten PBA which has been identified by the in situ FTIR spectra. Thus BNNSs possess higher nucleation property than graphene. Finally, a new polymer-substrate interaction induced nucleation mechanism was proposed to explain the nucleation efficiency difference between graphene and BNNSs.     

Gd3+/Y3+共掺对Nd:CaF2晶体光谱性能的影响

通过坩埚下降法生长了系列共掺Nd,Gd:CaF₂和Nd,Y:CaF₂晶体, 研究了Gd³⁺/Y³⁺共掺对Nd³⁺光谱性能以及Nd:CaF₂晶体晶胞参数的影响规律. 对于0.5 at.%Nd, x at.%Gd(x=2,5,8,10):CaF₂系列晶体, 当调控Gd³⁺掺杂浓度为2 at.%时, 具有最大的荧光寿命499 μs; 当Gd³⁺掺杂浓度为5 at.%时, 具有最大的吸收截面1.47×10^-20 cm², 最大的发射截面1.9×10^-20 cm²; 当Gd³⁺掺杂浓度为8 at.%时, 具有最佳的发射带宽29.03 nm. 对于0.6 at.%Nd, xat.%Y(x=2, 5, 8, 10):CaF₂系列晶体, Y³⁺掺杂浓度为5 at.%时, 有最大的吸收截面2.41×10^-20 cm², 最大的发射截面3.17×10^-20 cm²; 当Y³⁺掺杂浓度为10 at.%时, 具有最长的荧光寿命359.4 μs,并且具有最大发射带宽26 nm.     

High-power and wavelength tunable diode-pumped continuous wave Yb:SSO laser

A wavelength-tunable,efficient,and high-average power single diode-pumped continuons wave(CW) Yb:SSO laser is reported.A maximum output power of 8.8 W at 1 062.6 nm is obtained using the absorbed pump power of 11.7 W,which corresponds to a slope efficiency of 85.5% and an optical-to-optical conversion efficiency of 48.9%.The wavelength tuning of the Yb:SSO laser pumped by the 976-nm LD is also investigated.The results show the tuning range from 1 002.30 to 1 068.47 nm,which corresponds to a tunability range of 66.17 nm.     

三聚硫氰酸交联聚氯乙烯树脂的合成及其对Cu~(2+)的吸附性能

以三聚硫氰酸为原料,邻苯二甲酸二辛酯(DOP)为增塑剂,聚氯乙烯为大分子骨架,在MgO的存在下,合成得到了三聚硫氰酸交联聚氯乙烯树脂.对交联树脂吸附重金属离子的性能研究表明,合成树脂对Cu2+的吸附容量及选择性最大,在实验条件下吸附量达到1.056mmol/g;对其他金属离子吸附量很小,甚至不吸附.     

石蜡/P(MMA-co-AA)核壳结构相变蓄能微胶囊的制备

以熔点在58~60℃的半精炼石蜡作为相变芯材,与单体、分散剂水溶液形成核壳结构分散液,室温下自由基聚合制备甲基丙烯酸甲酯-丙烯酸的共聚物(P(MMA-co-AA))为壳材的微胶囊.分别用相差显微镜、扫描电镜、差示扫描量热分析仪和傅里叶变换红外光谱仪测定了微胶囊的形貌、热性能和壳材化学结构.微胶囊的直径范围为1~5μm,其中相变芯材的含量可达70%左右,具有较高的相变潜热(99 J/g),有望应用于空调、供暖等领域.     

La2O3对Yb3+掺杂的氧化钇透明激光陶瓷性能的影响

本文研究了La2O3的含量对(Yb0.05 Y0.95)2O3透明激光陶瓷的结构性能和烧结性能的影响.结果表明:随着La2O3含量的增加,拉曼光谱特征峰发生红移,声子能量降低,半高宽增大,相对强度先增大后减小;同时密度、相对密度和透过率都增大,陶瓷的晶粒减小,而当La2O3含量继续增加时,晶粒基本保持不变.但适量的La2O3掺杂量对(Yb0.05Y0.95)2O3透明激光陶瓷的发射性能影响不大.最合适的La2O3添加量为10at%,最合适的烧结温度为1700℃,最后样品的直线透过率可达到75%.     

冷坩埚法制备α-Al2O3多晶材料的工艺参数研究

采用冷坩埚法制备α-Al2O3多晶料,研究了引燃剂的形态、坩埚下降的速率、加料速率等工艺参数变化对所成形晶碇质量的影响。结果表明:采用的引燃剂为高纯铝片,坩埚下降速率为10 mm/h,采取加料速率为1 kg/min的最佳工艺条件,可制备出高致密度、高纯度的α-Al2O3多晶料。采用排水法测密度,用电感耦合等离子体原子发射光谱仪(ICP-OES)对原料粉和多晶块料中Ca、Fe、Na、Mg、K、Ti、Si、Cr等元素进行测定。结果表明:多晶块料中白色可用部分Ca、Fe、Na、K、Ti、Si、Cr等元素明显降低,说明采用冷坩埚法制备的氧化铝多晶料对原料粉具有一定的提纯作用,并且测量其堆积密度为2.6～2.8 g/cm3。因此采用冷坩埚法制备的α-Al2O3多晶料符合目前生长大尺寸蓝宝石对原料的要求。     

Growth and spectroscopic characteristics of Nd-doped PbWO₄ crystal

Nd-doped PbWO4 crystals are grown by using the modified Bridgman method.The spectroscopic properties of the crystals are investigated.The changes of the absorption band at 350 nm are discussed for samples annealed at 740℃ and 1040℃.The radiative lifetime of the 4 F 3/2 level is calculated by using the Judd-Ofelt theory according to the absorption spectrum of 0.5 at.% Nd-doped PbWO 4 crystal.The spontaneous Raman scattering properties of the crystals are analysed.