AN h-TYPE ADAPTIVE FINITE ELEMENT

ＡＮｈ－ＴＹＰＥＡＤＡＰＴＩＶＥＦＩＮＩＴＥＥＬＥＭＥＮＴ￥ＸｕＸｉｎｇ（徐兴）ＬｉｎｇＤａｏｓｈｅｎｇ（凌道盛）ＤｕＱｉｎｇｈｕａ（杜庆华）ＤｉｎｇＨａｏｊｉａｎｇ（丁皓江）（ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ．Ｈａｎｇｚｈｏｕ３１００２７．Ｐ．...     

疲劳／断裂加速试验载荷谱的编制及其实验研究

本文根据损伤等效原理，提出一套供随机疲劳试验用的加速载荷谱编制方法。由于此加速试验谱保持与原始实测谱主波型态和载荷序列不变，只对二级波进行等损伤折算，故经试验证实：加速试验谱对构件造成的损伤与原谱一致，即二者给出的寿命相当。加速试验谱可大大压缩试验时间，其占用的机时只有原谱的１／４左右。     

Evaluation of the 1077 keV γ-ray emission probability from ~(68)Ga decay

68Ga decays to the excited states of68Zn through the electron capture decay mode. New recommended values for the emission probability of 1077 keV γ-ray given by the ENSDF and DDEP databases all use data from absolute measurements. In 2011, JIANG Li-Yang deduced a new value for 1077 keV γ-ray emission probability by measuring the69Ga(n,2n)68Ga reaction cross section. The new value is about 20% lower than values obtained from previous absolute measurements and evaluations. In this paper, the discrepancies among the measurements and evaluations are analyzed carefully and the new values are re-recommended. Our recommended value for the emission probability of 1077 keV γ-ray is(2.72±0.16)%.     

硅油基底上受限金属薄膜自组装褶皱的原子力显微镜研究

利用喷雾装置在清洁载玻片上喷洒出各种尺寸(微米到毫米量级)的硅油滴,采用直流磁控溅射方法在硅油滴上沉积金属铬薄膜,研究了薄膜中由热应力引起的自组装褶皱.实验发现硅油滴上的铬薄膜受到油滴边缘的约束而具有受限的边界条件,其对褶皱的形貌具有很好的调控作用:褶皱呈垂直于边界的辐射状条纹;越靠近约束边界,褶皱的波长和振幅越小.褶皱的形貌特征还与薄膜厚度和硅油滴尺寸密切相关.随着膜厚的增加,褶皱在约束边界处首先形成,并逐渐扩展到油滴中心区域;相同尺寸油滴中心处的褶皱波长基本不变,而振幅随膜厚先增大随后减小.薄膜厚度相同时,随着油滴尺寸的增加,褶皱的波长和振幅都相应增加.进一步的研究表明:在沉积过程中,高能粒子的轰击和溅射源的热辐射导致硅油表面层的结构发生改变而形成聚合物层,在此基础上对褶皱的形貌特征和振幅演化给出合理的解释.     

基于悬浮式双芯多孔光纤的太赫兹偏振分离器

提出了一种基于悬浮式双芯多孔光纤的低损耗、宽带太赫兹偏振分离器.通过纤芯的多孔结构实现器件的低损耗特性,利用两个纤芯微结构的正交关系实现宽带的单偏振模式匹配.结构参数设计采用折射率反转匹配耦合法;数值计算采用全矢量有限元法;光纤基底材料选择太赫兹波段低损耗环烯烃共聚物COC.首先对单芯高双折射悬浮式多孔光纤的色散、模式双折射、基模在空气中的能量分数、以及损耗等特性进行了分析,在此基础上,对悬浮式双芯多孔光纤偏振分离器的特性进行了详细研究.发现该偏振分离器的工作带宽超过1.5 THz(0.8 THz到2.3 THz).其偏振分离长度和吸收损耗随频率的增大而增大,在1 THz,分离长度仅为0.66 cm;x,y两偏振的消光比分别为-14.64 dB和-14.84 dB,两偏振模式的实际吸收损耗均小于0.12 dB.相对于其他双芯光纤偏振分离器设计,该结构具有宽带、低损耗、设计简单、拉制容易、以及抗环境干扰等优点.     

ZnO-SnO2透明导电薄膜的制备及性能研究

采用二步成胶工艺制备ZnO-SnO₂透明导电薄膜,应用X射线衍射、原子力显微镜、紫外-可见分光光度计、薄膜分析仪及四探针仪等对薄膜的结构、表面微观形貌、透过率和导电性能进行表征.结果表明,锌锡摩尔比为9/12,退火温度为500 ℃时,薄膜的透过率达90%,电阻率为3.15×10-3 Ω·cm.与其它工艺相比,二步成胶工艺所制备出的ZnO-SnO₂透明导电薄膜性能优异.     

The electronic structures,Born effective charge tensors,and phonon properties of cubic,tetragonal,orthorhombic,and rhombohedral K0.5Na0.5NbO3： A first-principles comparative study

The electronic structures, Born effective charges（BECs）, and full phonon dispersions of cubic, tetragonal, orthorhombic, and rhombohedral K0.5Na0.5Nb O3 are investigated by the first principles method based on density functional theory.The hybridized states of Nb 4d and O 2p states are observed in the valence band, showing the formation of a strong Nb–O covalent bond which should be responsible for the displacement of Nb and O atoms. The abnormally large BECs of Nb and O indicate the possibility of phase instability induced by the off-center displacement of Nb and O atoms. The phonon dispersions reveal that the ferroelectric instability of K0.5Na0.5Nb O3 is dominated by Nb and O displacements with significant Na characteristics. In addition to the ferroelectric instability, there is also rotational instability coming from the oxygen octahedra rotation around one axis. Moreover, the Γ phonon properties of orthorhombic KNb O3, Na Nb O3, and K0.5Na0.5Nb O3 are also studied in detail.     

Evaluation of the 1077 keV γ-ray emission probability from 6SGa decay

6SGa decays to the excited states of aSzn through the electron capture decay mode. New recommended values for the emission probability of 1077 keV γ-ray given by the ENSDF and DDEP databases all use data from absolute measurements. In 2011, JIANG Li-Yang deduced a new value for 1077 keV γ-ray emission probability by measuring the 69Ga（n,2n） 6SGa reaction cross section. The new value is about 20% lower than values obtained from previous absolute measurements and evaluations. In this paper, the discrepancies among the measurements and evaluations are analyzed carefully and the new values are re-recommended. Our recommended value for the emission probability of 1077 keV γ-ray is （2.72±0.16）%.     

Syntheses, Structures and Characterization of Two New Pb~II Polymers Built on a Kinked Flexible Thiodiacetic Acid Ligand

Two new PbII metal-organic coordination polymers,namely,[Pb(tda)]n(1) and [Pb(tda)(phen)]n(2)(H2 tda = thiodiglycolic acid,phen = 1,10-phenanthroline),were synthesized under hydrothermal conditions and characterized by elemental analysis,IR,UV spectra,TG technique and X-ray crystallography.Complex 1 crystallizes in the orthorhombic system,space group Iba2 with a = 9.0417(14),b = 19.360(4),c = 7.5741(12),C4H4O4PbS,Mr = 355.32,V = 1325.8(4)3,Dc = 3.560 g·cm-3,F(000) = 1264,μ(MoKa) = 25.711 mm-1,S = 1.086 and Z = 8.The final refinement gave R = 0.0387 and wR = 0.0986 for 3077 observed reflections with I > 2σ(I).Complex 1 is a 2D infinite grid-like(4,4) topological structure constructed by PbII atoms and tda anions,in which tda ligands exhibit bis(syn,syn-bridging bidentate,chelating-bridging tetradentate) mode.Complex 2 crystallizes in the triclinic system,space group P1 with a = 8.3570(17),b = 8.7591(18),c = 10.895(2),α = 76.00(3),β = 80.50(3),γ = 77.61(3)°,C16H12N O4PbS,Mr = 535.53,V = 750.4(3)3,Dc = 2.370 g·cm-3,F(000) = 504,μ(MoKa) = 11.405 mm-1,S = 1.018 and Z = 2.The final refinement gave R = 0.0332 and wR = 0.0629 for 3360 observed reflections with I > 2σ(I).Complex 2 is a 1D chain structure,in which phen ligands are attached on both sides of the 1D chain and tda ligand exhibits a bis(syn,syn-bridging bidentate,chelating tridentate) mode.Finally,complex 2 is extended into a 2D supramolecular structure by strong π···π stacking interactions.     

间苯二乙酸构筑的2D锰(Ⅱ)配合物的合成及晶体结构

利用柔性配体合成了配合物[Mn(pda)(bpp)](1)(H2pda=1,3-phenylenediacetic acid,bpp=1,3-bi(4-pyridyl)propane),并对其进行了元素分析、红外光谱和X射线单晶衍射测定。配合物1属于正交晶系,空间群为Pnna,a=1.965 2(6)nm,b=1.103 3(4)nm,c=0.963 9(3)nm,α=β=γ=90.0°,V=2.089 8(12)nm3,Z=4,Dc=1.416 Mg.m-3,μ=0.664 mm-1,F(000)=924,R1=0.040 2,wR2=0.133 2(I>2σ(I))。配合物1的结构单元由1个MnⅡ、1个1,3-pda和1个bpp构成。bpp交替连接MnⅡ形成1D右手螺旋链,进一步通过1,3-pda的连接构成2D螺旋层。从c轴方向看,发现1DZ字链构成2D(4,4)网格结构。同时还研究了配合物的热稳定性和电化学性质。