Synthese und Struktur von dreikernigen Heterometall-Komplexen mit Nitridobrücken zwischen Re und Sn

Synthesis and Structure of Threenuclear Heterometallic Complexes with Nitrido Bridges between Re and Sn The threenuclear heterometallic complex [(Me₂PhP)₂ClRe(μ-Cl)N]₂SnCl₄ results from the reaction of ReNCl₂(PMe₂Ph)₃ with SnCl₄ in CH₂Cl₂. The brown, air-sensitive complex is diamagnetic. It crystallizes with two solvate molecules as [(Me₂PhP)₂ClRe(μ-Cl)N]₂SnCl₄ · 2 CH₂Cl₂ in the space group P 1 with a = 1189.1(2), b = 1262.3(2), c = 1776.7(3) pm, α = 86.04(2), β = 89.27(2), γ = 72.75(1)°, Z = 2. In the threenuclear complex two fragments (Me₂PhP)₂ClReN, which are connected by two Cl bridges, coordinate with their nitrido ligands one SnCl₄ molecule. The two resulting nitrido bridges complete the coordination of the Sn atom to a distorted octahedron with a cis arrangement of the N atoms. The bent nitrido bridges (Re–N–Sn = 155) are asymmetrical with distances Re–N = 168 pm and Sn–N = 225 pm. An incomplete exclusion of water during the synthesis leads to the formation of [(Me₂PhP)₃ClRe(μ-Cl)N]Sn₂(OH)Cl₇ · 2 CH₂Cl₂ in form of air-stable, red-violett crystals (P 1, a = 1074.1(2), b = 1251.1(3), c = 1685.0(1) pm, α = 99.61(2), β = 91.49(2), γ = 92.69(2)°, Z = 2). In the diamagnetic complex one molecule ReNCl₂(PMe₂Ph)₃ is coordinated by the nitrido ligand and one Cl bridge to the Sn atoms of a unit Sn₂(OH)Cl₇. In this unit the two Sn atoms are connected by one Cl and one OH bridge. The distances in the almost linear nitrido bridge (Re–N–Sn = 164.6) are Re–N = 170.5 pm and Sn–N = 219.8 pm.     

The Interplay between Strain,Sn Content,and Temperature on Spatially Dependent Bandgap in Ge1−x Sn x Microdisks

Germanium–tin (GeSn) microdisks are promising structures for complementary metal–oxide–semiconductor-compatible lasing. Their emission properties depend on Sn concentration, strain, and operating temperature. Critically, the band structure of the alloy varies along the disk due to different lattice deformations associated with mechanical constraints. An experimental and numerical study of Ge_1−x Sn _x microdisk with Sn concentration between 8.5 and 14 at% is reported. Combining finite element method calculations, micro-Raman and X-ray diffraction spectroscopy enables a comprehensive understanding of mechanical deformation, where computational predictions are experimentally validated, leading to a robust model and insight into the strain landscape. Through micro-photoluminescence experiments, the temperature dependence of the bandgap of Ge_1−x Sn _x is parametrized using the Varshni formula with respect to strain and Sn content. These results are the input for spatially dependent band structure calculations based on deformation potential theory. It is observed that Sn content and temperature have comparable effects on the bandgap, yielding a decrease of more than 20 meV for an increase of 1 at% or 100 K, respectively. The impact of the strain gradient is also analyzed. These findings correlate structural properties to emission wavelength and spectral width of microdisk lasers, thus demonstrating the importance of material-related consideration on the design of optoelectronic microstructures.     

2089 nm调Q锁模Tm,Ho∶CaYAlO4激光器

首次采用氧化石墨烯可饱和吸收体作为锁模启动元件在Tm,Ho∶CaYAlO4激光器中实现了稳定的被动调Q锁模运转。在3%输出耦合镜下,Tm,Ho∶CaYAlO4固体激光器获得了最低为293 mW的连续光出光阈值。在腔内引入氧化石墨烯可饱和吸收体后,当吸收抽运功率增大到1859 mW时,Tm,Ho∶CaYAlO4激光器进入稳定的调Q锁模运转状态。当抽运功率达到3 W时,获得中心波长为2089 nm、斜效率为10.1%、对应最大输出功率为213 mW的被动调Q锁模脉冲,重复频率为100 MHz,调Q包络中锁模脉冲的调制深度接近100%。     

Nuclear chart in covariant density functional theory with dynamic correlations: From oxygen to tin

Nuclear masses of even-even nuclei with the proton number 8≤Z≤50(O to Sn isotopes)from the proton drip line to neutron drip line are investigated using the triaxial relativistic Hartree-Bogoliubov theory with the relativistic density functional PC-PK1.Further,the dynamical correlation energies(DCEs)associated with the rotational motion and quadrupole-shaped vibrational motion are taken into account by the five-dimensional collective Hamiltonian(5DCH)method.The root-mean-square deviation with respect to the experimental masses reduces from 2.50 to 1.59 MeV after the consideration of DCEs.The inclusion of DCEs has little influence on the position of drip lines,and the predicted numbers of bound even-even nuclei between proton and neutron drip lines from O to Sn isotopes are 569 and 564 with and without DCEs,respectively.     

邻氯苯基萤光酮-吐温-80光度法测定铝合金中痕量锡

本文研究了非离子表面活性剂Tween-80存在下,锡与邻氯苯基萤光酮的适宜显色反应条件。结果表明,在0.50～1.25mol/L硫酸介质中,Sn(N)与O-CI-PF、Tween-80形成一稳定橙色配合物。其最大吸收在510nm处,表观摩尔吸光系数为1.68×10~5,锡量在0～12.5μg/25mL范围内符合比耳定律。显     

Cs2HfCl6和Cs2HfCl6∶Tl晶体的生长、光学和闪烁性能研究

本文使用坩埚下降法制备了ø7 mm的未掺杂Cs₂HfCl₆与Cs₂HfCl₆∶0.2%Tl(摩尔分数)单晶,对晶体样品进行了物相、杂质含量、光学和闪烁性能的研究。该晶体属于立方晶系,空间群为Fm3m。在荧光和X射线激发下,未掺杂Cs₂HfCl₆晶体的发光主峰皆为380 nm,对应于自陷激子发光。Cs₂HfCl₆∶0.2%Tl晶体在荧光和X射线激发下,发射光谱中除了存在380 nm处的自陷激子发光,也存在505 nm处Tl⁺的sp-s²跃迁发光。Cs₂HfCl₆和Cs₂HfCl₆∶0.2%Tl晶体的光输出分别为37 000 photons/MeV和36 500 photons/MeV,在662 keV处的能量分辨率皆为3.5%。在¹³⁷Cs源激发下,Cs₂HfCl₆晶体的闪烁衰减时间为0.37 μs (4.2%)、4.27 μs (78.9%)和12.52 μs (16.9%),Cs₂HfCl₆∶0.2%Tl晶体的闪烁衰减时间为0.33 μs (3.5%)、4.09 μs (81.9%)和10.42 μs (14.5%)。     

ITER用内锡法Nb3Sn超导线材的不可逆温度研究

本文采用超导量子干涉仪(SQUID)测定了一种国际热核聚变实验堆(ITER)项目用内锡法Nb3Sn超导线材的不可逆温度,测量方法是在恒定磁场下循环温度,即将温度以一定间隔从10K上升到20K,然后再返回到10K,测定磁矩的偏离温度.所得结果可用于从生成最佳Nb-Sn相组成方面来优化A15相成相热处理制度.本研究得出的结论是,对于像ITER使用的高场磁体超导线来说,鉴于其需要在较高磁场下有高的临界电流密度,就需要将超导线的热处理温度适当提高一些.本实验所用Nb3Sn超导线材的最适宜热处理制度为675°C/128小时,这样可以得到最佳不可逆温度特性,即最佳的A15相组成.