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951.
本研究通过壳模型计算研究了N=51的同中子素91Zr、93Mo和95Ru中高自旋晕态21/2+的同核异能态现象。计算发现,低角动量的p1/2轨道上的质子是仅在93Mo中存在21/2+晕阱的主要原因。同时,本工作还研究了N=52的同中子素92Zr、94Mo和96Ru中101+-121+能级结构的系统性,发现94Mo中的101+-121+能级间隙相对最小,考虑到与93Mo的17/21+-21/21+能级相似的组态,这一结果为93Mo中出现21/2+晕阱提供了补充性的论证。Isomerism of the high-spin yrast 21/2+ states of the N=51 isotones 91Zr, 93Mo and 95Ru has been investigated using the shell model calculations. It is found that the low-j πp1/2 is responsible for the only yrast trap in 93Mo. In addition, the relatively smaller 101+-121+ level spacing in 94Mo has been found by investigating the systematics of the 101+-121+ level structures in the N=52 isotones 92Zr, 94Mo and 96Ru. This result provides a supplementary argument to the origin of the 21/2+ yrast trap in 93Mo from the viewpoint of the similarity between the configurations of 101+-121+ states in 94Mo and those of 17/21+-21/21+ states in 93Mo. 相似文献
952.
介绍了一种利用金属材料的热膨胀而产生的位移代替传统的机械电机提拉晶体的新方法,可以预见这种新型提拉方法既可以消除晶体提拉过程中由于拉速的不平滑而引进的晶体生长条纹,同时也可以作为研究晶体生长机理的有力工具,另一方面,该方法可以用来提拉这样的一灰晶体,这种晶体溶质的浓度周期地分布于其中,且其周期远小于用机械电机所提拉的晶体溶质浓度的周期,同时,另一种新颖的控温方式被首次提出,即先把金属棒加热膨胀至一定的长度再冷却使之收缩,由于这种控温方式温度波动极端微小,使得金属棒收缩所产生的位移随时间的变化率达到微观的平滑极限。 相似文献
953.
954.
Experimental Verification of Left-Handed Metamaterials Composed of Coplanar Electric and Magnetic Resonators 下载免费PDF全文
We verified experimentally left-handed metamaterials (LHM) composed of coplanar electric and magnetic resonators. A typical LHM sample composed of coplanar resonator unit cells was fabricated, investigated and tested. The experimental results show that the tested sample has a left-handed band of width 1.4 GHz in the X band. The experimental results agree quite well with the simulation ones. Moreover, both the simulation and experimental results show that the LHM under study can automatically achieve good impedance-matching in the left-handed band. 相似文献
955.
A new long-lasting phosphorescence (LLP) phosphor, Sr2SnO4:Sm3+ which emits reddish-orange LLP upon UV-excitation, is prepared by a conventional high-temperature solid-state method. After irradiation under 247-nm UV light, Sr2SnO4:Sm3+ emits an intense reddish-orange emission afterglow from the 4G5/2 to 6HJ (J = 5/2,7/2,9/2) transitions. The afterglow decay curve of the Sm3+-doped Sr2SnO4 phosphor contains a fast decay component and another slow decay one. Due to the presence of the slow decay component, the afterglow can be seen with the naked eye in the dark clearly for more than 1 h after removal of the excitation source. 相似文献
956.
利用耗散粒子动力学模拟方法研究了两嵌段共聚高分子薄膜中的一些微观性质. 结果表明:薄膜中共聚高分子链的均方根末端距2e>1/2、均方根回旋半径2g>1/2与薄膜厚度l、不同粒子间的相互作用强度aij、粒子与薄膜边界间的排斥作用强度apb均呈线性关系,而均方键长与aij、apb呈线性关系,随l增加则呈现出波浪形趋势. 2e>1/2与2g>1/2的变化趋势可以相互对应. 任一组分在薄膜中的密度分布可以通过其与薄膜边界间的相互作用来有效控制与调节. 相似文献
957.
采用微波辅助加热方法,2,3-二苯基吡嗪(DPP)与水合三氯化铱(IrCl3·3H2O)反应制备了[Ir(DPP)3],通过1H NMR、元素分析和质谱方法对配合物结构进行了表征,并研究了配合物的吸收光谱和光致发光光谱. 结果表明,配合物Ir(DPP)3在382和504 nm处存在单重态1MLCT(金属到配体的电荷跃迁)和三重态3MLCT的吸收;在573 nm 处有较强的金属配合物三重态的磷光发射. 相似文献
958.
Cheng-Liang Ni Xiao-Hui Song Hong Yan Xiu-Qing Song Ru-Gang Zhong 《Ultrasonics sonochemistry》2010,17(2):367-369
Diethyl 2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates (1) have been synthesized by the reaction of aryl aldehyde and 1,3-diketone catalyzed by ZnCl2 under ultrasound irradiation. The effects of changes in the ultrasonic power, temperature, and reaction time are discussed. With the optimized reaction conditions, various aryl aldehydes were used to synthesize 4H-pyrans (1) under the influence of ultrasound irradiation. Compared with the conventional thermal methods, the remarkable advantages of this method are the simple experimental procedure, shorter reaction time and high yield of product. 相似文献
959.
XiaoBo Chen ZengFu Song JinGuang Wu N. Sawanoboi M. Ohtsuka YongLiang Li Jing Zhou Ce Wang JinYing Liu Qiang Tian Ping Sun HongMei Jing 《中国科学G辑(英文版)》2008,51(12):1868-1876
The ultraviolet upconversion luminescence of Tm3+ ions sensitized by Yb3+ ions in oxyfluoride nanophase vitroceramics when excited by a 975 nm diode laser was studied. An ultraviolet upconversion
luminescence line positioned at 363.6 nm was found. It was attributed to the fluorescence transition of 1D2→3H6 of Tm3+ ion. Several visible upconversion luminescence lines at 450.7 nm, (477.0 nm, 462.5 nm), 648.5 nm, (680.5 nm, 699.5 nm) and
(777.2 nm, 800.7 nm) were also found, which result respectively from the fluorescence transitions of 1D2→3F4, 1G4→3H6, 1G4→3F4, 3F3→3H6 and 3H4→3H6 of Tm3+ ion. The careful measurement and analysis of the variation of upconversion luminescence intensity F as a function of the 975 nm pumping laser power P prove that the upconversion luminescence of 1D2 state is partly a five-photon upconversion luminescence, and the upconversion luminescence of 1G4 state and 3H4 state are respectively the three-photon and two-photon upconversion luminescence. The theoretical analysis suggested that
the upconversion mechanism of the 363.6 nm 1D2→3H6 upconversion luminescence is partly the cross energy transfer of {3H4(Tm3+), 3F4(Tm3+), 1G4(Tm3+)→1D2(Tm3+)} and {1G4(Tm3+)→3F4(Tm3+), 3H4(Tm3+)→1D2(Tm3+)} between Tm3+ ions. In addition, the upconversion luminescence of 1G4 and 3H4 state results respectively from the sequential energy transfer {2F5/2(Yb3+)→2F7/2(Yb3+), 3H4(Tm3+)→1G4(Tm3+)} and {2F5/2(Yb3+) →2F7/2(Yb3+), 3F4(Tm3+)→3F2(Tm3+)} from Yb3+ ions to Tm3+ ions.
Supported by the National Natural Science Foundation of China (Grant No. 10674019) 相似文献
960.