大尺寸Er,Yb:YAG单晶的生长及其性能

Er^(3+)和Yb^(3+)共掺杂的YAG晶体是一种非常重要的光学晶体,目前,该晶体已经广泛应用于高功率固体激光器,但是采用提拉法生长大尺寸、低缺陷的掺杂YAG晶体仍然面临很多挑战。本工作采用快速提拉法成功获得了直径为80 mm、长度为230 mm的Er^(3+)和Yb^(3+)共掺杂的YAG单晶。采用不同测试方法评价其结构、掺杂浓度、光吸收、发光性能和刻蚀缺陷。晶片不同位置的拉曼峰峰位以及半峰宽没有明显变化,说明晶片中心和边缘部分的晶体结构和应变是均匀的。刻蚀结果表明,腐蚀坑均匀分布在整个腐蚀表面上,没有观察到位错腐蚀坑特征,这意味着晶体接近完美。Er^(3+)和Yb^(3+)在不同波长下的强发光峰以及辉光放电质谱结果证明Er,Yb:YAG单晶中成功掺杂了稀土离子。本工作采用提拉法成功生长了大尺寸、低缺陷的Er,Yb:YAG单晶,证实了快速生长方法对YAG晶体中掺杂双稀土离子是有效的。

激光测照器光学系统小型化的研究

为解决传统激光测照器光学系统只实现光束准直、光束均匀度较差的问题,对激光测照器光学系统小型化进行研究。对激光光束进行扩束,利用盖师贝格-撒克斯通(Gerchberg-Saxton,GS)改进算法设计用于光束匀化和准直的二元光学元件B1和B2,根据光功率恒定原理,建立光束匀化的坐标变换公式,在ZEMAX中编写宏指令设计非球面透镜组光学系统。结果表明:该系统能使光束均匀度达到96.2%,发散角优于0.25 mrad,实现了光学系统的小型化(光学系统结构为110 mm×42 mm×42 mm)。

Mechanism of the Effect of Bacillus coagulans on Production Performance of Laying Hens in Late Laying Period

[Objective]The paper was to investigate the mechanism of Bacillus coagulans preparation in improving production performance of laying hens in late period of laying.[Method]A total of 648 individuals of"Jingfen 1"laying hens(66 weeks of age)in late period of laying were randomly divided into four groups,six replicates each group,and each group had 27 individuals of laying hens.The laying hens in control group were fed with basal diet,and those in experimental groupsⅠ,Ⅱ and Ⅲ were fed with the basal diets added with 3.33×10^6,1×10^7,3.33×10^7 CFU/g B.coagulans,respectively.The pretrial lasted one week,and the formal test lasted eight weeks.[Result]Compared with the control group,the laying rate in group Ⅰ increased significantly,and the feed-gain ratio in experimental group Ⅱ decreased noticeably while the spleen index increased remarkably;the alkaline phosphatase activities and blood calcium content in experimental groups Ⅰ,Ⅱ and Ⅲ increased significantly(P<0.05),while the triglyceride content decreased remarkably(P<0.05);the urea content in experimental groups Ⅰ and Ⅱ decreased obviously(P<0.05).Adding B.coagulans significantly increased the specific activity of amylase,lipase and protease in various intestinal mucosa of small intestine(P<0.05);adding B.coagulans significantly increased the content of follicle-stimulating hormone(FSH)and estradiol(E2),and significantly increased the mRNA expression of follicle stimulating hormone receptor gene(FSHR).[Conclusion]B.coagulans preparation could significantly improve the production performance of laying hens in late period of laying;appropriately enhance the immune capacity of laying hens;improve the serum biochemical indicators;increase the activity of digestive enzymes in the small intestine;and promote the release of gonadal hormone and the mRNA expression of FSHR gene in the ovary.

Theoretical Studies of the C_(60) and Alkali Metal-Containing Complexes C_(60)M

The electronic structures of C_(60) ahd C_(60) M(M=Li,Na,K,Rb and Cs)were calculated by using an atom superposition and electron delocalization molecular orbital method.The results indicate that s valence electron of the atom of alkali metal was completely transferred to 5T_(1u) orbital of C_(60).The stabilization energy of the system results mainly from the electrostatic interaction between polarized C_(60) and alkali metal atom.

超快高温制备正钽酸铕及发光性能研究

稀土钽酸盐具有密度大、热稳定性高、介电常数大、良好的化学稳定性和发光特性,在热障涂层、闪烁探测器、质子传导氧化物燃料电池等领域有着重要的应用。利用常规固相反应法制备稀土钽酸盐烧结温度高且通常需要数个小时,本文采用超快高温烧结法在约6 s内制备了C2/c结构的亚稳相M-EuTaO_(4)粉末,烧结温度为2740~2790℃,比普通烧结方法快3000~8000倍。利用粉末X射线衍射(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM-EDS)、紫外可见光谱(UV-VIS)、荧光光谱(PL)对合成的样品进行表征。荧光寿命衰减曲线拟合结果显示,检测波长为λ=611 nm时,M-EuTaO_(4)快成分和慢成分寿命分别为54.31μs(43.56%),124.46μs(56.44%),平均荧光寿命为0.0939 ms。超快高温烧结方法在高温材料的快速制备筛选以及寻找亚稳相结构方面具有很好的应用潜力。