行波管用钨铼合金中高含量铼的X射线荧光光谱测定

根据行波管用的关键材料-钨铼合金中高含量铼测定的需求,研究了用X射线荧光(XRF)光谱法测定铼时所存在的基体效应、谱线重叠和背景干扰的影响,从理论上解释了XRF二元比例法校正曲线线性差的原因。理论和实验结果均表明：直接用Re Lα分析线强度绘制的校正曲线比二元比例法可以获得更好的线性。本法具有快速准确的特点,分析结果与化学方法一致,在生产控制中应用效果显著。     

ICP—OES测定地质样品中微量铼

应用ICP-OES测定矿样中铼,样品经过碱熔水浸取,过滤得到的滤液用环己酮萃取分离,水和三氯甲烷反萃取后得到的水相,酸化后,进行铼的测定。着重讨论了萃取分离的必要性和Mo对铼的干扰,并通过各种参数条件的优化选择进行了铼的测定,取得满意结果。本法准确度高,灵敏度高,分析线性宽,分析速度快,测定范围为0.5-100μg/mL,RSD在2.57%—6.81%之间。     

ICP-AES法测定DD2单晶合金中的铼和铪

本文采用ICP－AES法对DD2单晶合金中铼、铪的测定进行了研究，着重考察了DD2合金中基体及共存元素对铼，铪测定的影响，采用基体匹配法消除基体干扰，测定了DD2合金中的铼，铪含量，得到了较好的精密度和准确度。方法简便快速，可获得满意的分析结果。     

加入法测钨铼丝中的钾

钨铼丝中随微量钾的增加，材料的可塑性增加，使产品经贸耐用，但钾的含量大于１５０μｇ．ｇ＾－１时，其材料硬度过高，成形困难而难于加工，一般钨铼丝中微量钾的测定采用直接法，因基体产生基体效应而使结果超差。作者拟定了用过氧化氢分解样品，稀释后加标准钾溶液。在氯化镧存在下，用乙炔火焰原子吸收仪测其吸光度，作曲线计算样品中钾的含量。此方法快速方便，结果准确，消除了基体效应。     

电感耦合等离子体原子发射光谱法测定高纯铼酸铵中Ca、Cd、Mn、Fe、Mg、Al、Cu、Co、Mo、Pb、Sn和Ni

本文介绍了电感耦合等离子体发射光谱法（ICP－AES）测定高纯铼酸铵中12个杂质元素的方法。采用挥发健康基体，探讨了高铼酸铵基体的干扰及其消除办法。ICP－AES测定结果的准确度和精密度均能满足分析要求。     

层间电荷转移增强二硫化铼/石墨烯异质结薄膜的反饱和吸收特性

提高二维纳米材料的非线性光学响应,推动非线性光学在光电子领域的应用,是当前的一项巨大挑战,而构建高质量的范德瓦耳斯异质结,研究其非线性光学响应的内在机理,是解决途径之一.本文采用液相剥离结合真空抽滤技术,选择不同的混合方式(粉末混合、超声后混合、离心后混合),构建了三种二硫化铼/石墨烯异质结薄膜,并利用拉曼光谱仪、近红外吸收光谱仪以及原子力显微镜等对其进行了光学表征.采用自主搭建的高重复频率、窄脉宽飞秒Z扫描系统,重点研究了上述异质结薄膜在800 nm处的非线性光学特性,得到了其三阶非线性极化率虚部、品质因数等重要的非线性光学参数.结果 表明:异质结的成功构建使得材料的非线性光学响应显著增强,超声后混合的二硫化铼/石墨烯薄膜的品质因数是纯二硫化铼薄膜的3.5倍,纯石墨烯的1.6倍;超声后混合的二硫化铼/石墨烯薄膜具有最高的反饱和吸收特性,其品质因数相较于粉末混合、离心后混合的异质结薄膜分别提高了44％和27％.本文为范德瓦耳斯异质结的制备提供了新思路,同时也为飞秒光限幅器件的研究打下了理论基础.     

铼配合物光异构化的拉曼和红外光谱研究

光敏分子和它们在光作用下发生的异构化一直是分子光化学研究领域中感光趣的课题。含有光敏基团的铼配合物的一个新颖特性是其具有电致发光性质。为弄清结构与功能性质的联系 ,本文研究了 Re(CO) 3 (2 ,2 '-联吡啶 ) [4- (4'-硝基苯己烯基吡啶 ) ]高氯酸盐的 FT-Raman和 FT- IR光谱 ,指认了光照前和光照后的拉曼位移。讨论了这些变化与金属到配体电荷转移的联系     

稀有金属铼

<正>铼,是一种银白色的高熔点金属,是拥有稳定同位素的元素中最后一个被发现的。铼不但具有良好的塑性、机械性、抗蠕变性,同时它还有着良好的耐磨与抗腐性能。铼主要存在于辉钼矿中,储量十分的稀少,其产量就更加少了,是昂贵的稀有金属。目前世界探明的铼储量大约10000吨左右,每年全球产量在30至50吨之间。其中智利铼的产量最高,其次为美     

铼的弹性剪切参数C44对温度与压力响应的原位拉曼光谱研究

铼具有高体积弹性模量、高熔点、优良的抗蠕变性能,是一种重要科学研究与工程应用材料。铼的弹性剪切系数C₄₄对温度和压力的响应特性对铼及其合金材料的设计与工程应用具有重要意义。激光拉曼散射技术在研究不同温度和压力条件下六方密堆积结构(hcp)金属的弹性剪切系数C₄₄上具有独特的优势。但由于金属的强反射作用和浅的穿透深度,hcp金属的低波数拉曼散射信号往往很难获取,在一定的温度和压力加载下拉曼信号的获取尤为困难。利用侧向激发拉曼散射技术,有效降低了金属强反射对拉曼光谱采集的影响,成功测量到多晶铼在不同压力与温度条件下的E_2g拉曼振动模,获得铼在常温常压条件的弹性剪切系数(C₄₄=133 GPa)以及其弹性剪切系数C₄₄对温度和压力的响应特性。研究结果表明,多晶铼的弹性剪切系数C₄₄模量随压强的增加而增大,随温度的增加而减小。这也为用光散射方法研究金属材料剪切模量提供了良好研究方法。     

二硫化铼的原位高压偏振拉曼光谱

高压调控是一种能够对材料的结构、电学、光学等物理特性实现高效、连续且可逆变化的实验手段;拉曼光谱则是一种能够对材料的晶相等结构信息实现精准、快速、无损分析的研究方法.本文结合了金刚石对顶砧高压技术和原位偏振拉曼光谱技术,对二硫化铼(ReS₂)晶体的拉曼振动模式随压强的演变过程进行了深入研究.实验发现ReS₂的常压相(1T’)在3.04 GPa的压强下转变为一个扭曲1T’相,继而在14.24 GPa压强下发生了Re₄原子簇的层内形变,并且在22.08和25.76 GPa分别发生了不同方向的层间无序叠加向有序叠加的转变.这一系列独特的实验现象充分展现了该二维材料的面内各向异性,并证实ReS₂晶体的各向异性随压强的增加而变得愈发显著.本文研究表明压强在调节材料性能方面的关键作用,揭示了ReS₂晶体在制备各向异性光学器件和光电器件等方面的潜力.     

Das ß-Spektrum des natürlichen Rhenium 187

TheΒ-spectrum of naturally occuring¹⁸⁷Rhenium was measured using the vapour of (C₅H₅)₂ReH as a gaseous source in a “walless” proportional counter. The counter was enclosed in a glass envelope and was operated at temperatures up to 150 ?C. The Kurie plot was found to be a straight line between 1.1 keV and the endpoint at (2.65±0.04) keV.     

Rhenium diboride's monocrystal elastic constants, 308 to 5 K

The five independent moduli required to construct the complete monocrystal elastic modulus tensor of the hexagonal-symmetry superhard compound ReB(2) were measured from 308 to 5 K using resonant ultrasound spectroscopy on a special-texture polycrystal. This is possible because, confirmed by X-ray diffraction, the specimen measured was composed of grains with hexagonal axes parallel so that its polycrystal elastic response is identical to a monocrystal and because hexagonal-symmetry solids are elastically isotropic in the plane perpendicular to the hexagonal axis. Along the hexagonal (c) axis, C(33) (0) = 1021 GPa, nearly equal to C(11) of diamond, and consistent with the superhard properties. However, in the (softer) isotropic plane, C(11) (0) = 671 GPa, much lower than diamond. The changes of C(ij) with temperature are very small and smooth. The Debye temperature was computed to be 738 K, and using a high-temperature approximation, the Gru?neisen parameter is γ = 1.7.     

Induced Quasi-Dynamic Disorder in a Structure of Rhenium Ion-Implanted Quartz Glass

Physics of the Solid State - The ultraviolet (UV) absorption spectra were studied in UV–Vis–IR quartz glasses exposed to the rhenium ion irradiation at the energy of 30 keV. An increase...     

双水相体系中钼与铼的分离

在聚乙二醇2000-NaOH双水相体系,研究了Mo(Ⅵ)与Re(Ⅶ)的萃取行为。在6mol/L的NaOH碱液体系中,通过加入掩蔽剂的方法,可实现Mo(Ⅵ)与Re(Ⅶ)的萃取分离,同时探讨了聚乙二醇对金属离子的萃取机理。     

Photoluminescence Electron-Transfer Quenching of Rhenium(I) Complexes with Organic Sulfides

Electron-transfer(ET) from organic sulfides to excited state rhenium(I)-based heteroleptic tricarbonyl complexes [Re(bpy)(CO)₃(py)]⁺ (I) and [Re(bpy)(CO)₃(ind))]⁺ (II) in acetonitrile solution is facile and luminescence quenching constants, k_q, are in the range 10⁵–10⁸ M⁻¹s⁻¹. The detection of the sulfide radical cation in this system using time-resolved absorption spectroscopy is a direct evidence for the ET nature of the reaction. The k_q values for the quenching of Re(I)-complexes with organic sulfides are analyzed with a scheme involving rate controlling electron transfer process. The measured rate constants for the electron transfer (ET) reaction are close to the values calculated from Marcus theory.     

High-efficiency Red Electrofluorescence Devices Employing a Rhenium Complex as Phosphorescent Sensitizer

Efficiencies of up to 7.81 cd/A and brightness of 8843 cd/m² are obtained based on green–yellow phosphorescent material, fac 4, 4′-bi (tert-butyl)-2, 2′-bipyridine Re(CO)₃Cl[(Bu ^t bpy)Re(CO)₃Cl] doped into 4,4′-N,N′-dicarbazole-biphenyl (CBP) host. We also fabricate high-efficiency red devices by introduction of (Bu^tbpy)Re(CO)₃Cl as a sensitizer, and the undoped ultrathin layer 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) as fluorescent acceptor. Förster energy of triplet and singlet are efficient due to appropriate overlap between emission spectrum of (Bu ^t bpy)Re(CO)₃Cl and absorption spectrum of DCJTB.     

Rhenium(IV) as a sensitizer for two-step blue up-converters

The fluorescence of rhenium(IV) and thulium(III) ions doped singly and together in the most host lattice Cs₂NaYCl₆ is studied. Energy transfer between Re⁴⁺ and Tm³⁺ ions is demonstrated and is shown to provide two-step up-conversion to the ¹D₂ and ¹G₄ levels of the Tm³⁺ ion, both of which emit in the blue.