硫系光纤的色散测量

利用相移测量了单模As2 S3 光纤在 1 5 5 μm附近的色散。测量结果显示 ,As2 S3 光纤的材料色散为- 39ps/ (km·nm)。特殊的色散特性 ,预示了硫系光纤及其器件广阔的应用前景。     

[FeFe]‐Hydrogenase with Chalcogenide Substitutions at the H‐Cluster Maintains Full H2 Evolution Activity

The [FeFe]‐hydrogenase HYDA1 from Chlamydomonas reinhardtii is particularly amenable to biochemical and biophysical characterization because the H‐cluster in the active site is the only inorganic cofactor present. Herein, we present the complete chemical incorporation of the H‐cluster into the HYDA1‐apoprotein scaffold and, furthermore, the successful replacement of sulfur in the native [4Fe_H] cluster with selenium. The crystal structure of the reconstituted pre‐mature HYDA1[4Fe4Se]_H protein was determined, and a catalytically intact artificial H‐cluster variant was generated upon in vitro maturation. Full hydrogen evolution activity as well as native‐like composition and behavior of the redesigned enzyme were verified through kinetic assays, FTIR spectroscopy, and X‐ray structure analysis. These findings reveal that even a bioinorganic active site with exceptional complexity can exhibit a surprising level of compositional plasticity.     

Temperature-modulated nanostructures of ytterbium-doped Cobalt Selenide (Yb-CoSe) for photovoltaic applications

This research investigated the influence of temperature variation on the properties of ytterbium-doped cobalt Selenide (Yb-CoSe) nanostructures synthesized via the electrodeposition technique. The structural, optical, morphological, and elemental features of the synthesized films were investigated through X-ray diffractometry (XRD), ultraviolet–visible (UV–vis) spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) respectively. XRD results showed prominent peaks with a cubic phase. Good absorbance values in the visible region and reduced band gap energies upon the introduction of ytterbium were obtained from the optical analysis. Morphological results gave nanoclusters of varying sizes spread throughout the substrate surface. The elemental constituents of the deposited films were evident from the EDX spectra. The synthesized films have significant potential to be used in solar cells and optical devices.     

Tm~(3+)掺杂Ge-Ga-S玻璃微球-石英光纤锥耦合系统的荧光回廊模特性

以熔融淬冷法自制了Tm~(3+)掺杂Ge-Ga-S硫系玻璃,并以此为基质材料,用漂浮粉料熔融法制备了直径分布为50—200μm的高品质因数(Q10~4)的有源硫系玻璃微球谐振腔.在显微镜下优选出一颗表面质量好、球形度较高、直径为72.84μm的微球,与氢氧焰扫描拉锥法制备的一根腰锥直径为1.93μm的石英光纤锥进行近场耦合.根据基质材料的吸收光谱特性,选用808 nm的半导体激光器作为抽运源.实验测得光纤锥倏逝波场激发出了掺Tm~(3+)硫系玻璃微球在1460 nm附近的荧光回廊模式,其典型共振峰间隔为4.39 nm.实验测得的荧光回廊模式与米氏散射理论计算结果符合度较高(最大误差仅为0.047%),验证了本文提出的掺Tm~(3+)硫系微球制备及耦合工艺的可行性.     

Adhesive As-S-Se-I immersion lenses for enhancing radiation characteristics of mid-IR LEDs operating in wide temperature range

The influence of As-S-Se-I chalcogenide glass lenses on the integral and spectral power and pattern of LED radiation has been shown. Simulation of the influence of the refractive index on the integral power for two lens shapes has been performed. The wettability and adhesion force of As-S-Se-I melt has been determined for several electronic engineering materials. Mechanical stresses between chalcogenide glass and adjacent diode body materials have been calculated for −100 to 53 °C temperature range. Stability of the immersion lenses against cracking has been experimentally investigated for −150 to 53 °C temperature range.     

Effect of germanium addition on the physical properties of Se–Te glassy semiconductors

The effect of germanium addition on the physical properties, i.e. density, molar volume, compactness, number of lone-pair electrons, average coordination number, heat of atomization, mean bond energy, cohesive energy and glass-transition temperature, of (Se₈₀Te₂₀)_{100? x} Ge _x (x = 0, 2, 4, 6) bulk glassy alloys was investigated. The density of the glassy alloys is found to decrease with increasing Ge content. The molar volume and compactness of the structure of the glass were determined from the measured density. The mean bond energy is proportional to the glass-transition temperature. The cohesive energy of the samples has been calculated using a chemical bond approach and is correlated with an increase in the optical energy gap with increase in the Ge content. The heat of atomization was also calculated and correlated with the optical energy gap. The glass-transition temperature has been estimated using different methods and is found to increase with an increase of Ge content.     

中红外高保偏硫系玻璃双芯光子晶体光纤耦合特性研究

设计了一种中红外硫系玻璃双芯光子晶体光纤,利用多极法和模式耦合基本理论研究了这种光纤的耦合特性.数值模拟发现,空气孔间距Λ = 5.4 μm,空气孔半径为r = 1.35 μm,空气填充率d/Λ = 0.5的光纤,在归一化波长λ/Λ = 2.04 μm处双折射可以达到0.551×10^-2,在归一化波长λ/Λ = 0.93 μm处x偏振方向的耦合长度为145.32 μm,y偏振方向的耦合长 关键词： 双芯光子晶体光纤 硫系玻璃 双折射 耦合长度     

Superconductivity in CuIr2-xAlxTe4 telluride chalcogenides

The relationship between charge-density-wave (CDW) and superconductivity (SC), two vital physical phases in condensed matter physics, has always been the focus of scientists' research over the past decades. Motivated by this research hotspot, we systematically studied the physical properties of the layered telluride chalcogenide superconductors CuIr$_{2-x}$Al$_{x}$Te$_{4}$ ($0 \leqslant x \leqslant 0.2$). Through the resistance and magnetization measurements, we found that the CDW order was destroyed by a small amount of Al doping. Meanwhile, the superconducting transition temperature ($T_{\rm c}$) kept changing with the change of doping amount and rose towards the maximum value of 2.75 K when $x=0.075$. The value of normalized specific heat jump ($\Delta C/\gamma T_{\rm c}$) for the highest $T_{\rm c}$ sample CuIr$_{1.925}$Al$_{0.075}$Te$_{4}$ was 1.53, which was larger than the BCS value of 1.43 and showed the bulk superconducting nature. In order to clearly show the relationship between SC and CDW states, we propose a phase diagram of $T_{\rm c}$ vs. doping content.     

Amorphous to crystalline phase transition in glassy Se65Te20Ag15 alloy

In the present work, the amorphous to crystalline phase transition of chalcogenide glass Se₆₅Te₂₀Ag₁₅ has been studied using differential scanning calorimetric (DSC) measurements. The heating rate dependence of crystallization peaks has been used for the determination of activation energies of glass transition (E _g) and crystallization (E _c). Different non-isothermal methods have been used for this purpose. Other useful kinetic parameters such as the order parameter (n), the numerical factor of crystallization mechanism (m) and the frequency factor (K _o) of the rate constant (K) have been also determined.     

Ac electrical conductivity and dielectric relaxation behavior of amorphous Selinum36 Antimony31Cubber33 thin films

ABSTRACT

The alternating-current (Ac) conductivity measurements and dielectric behaviors were observed in the range of temperature (from 303 to 393?K) and in the frequency range from 10² to10⁶?Hz for amorphous films of Selinum₃₆ Antimony₃₁ Cubber₃₃ chalcogenide glass. The ac conductivity has temperature dependency and the frequency dependency. The reduction of the exponent S values with raising temperature was introduced with the correlated barrier hopping model. The maximum height of the barrier W_M for Sellinum₃₆ Antimony₃₁Cubber₃₃ films is reliable with carrier hopping over a potential barrier. The number of localized states per unit volume at the Fermi level enhances with the elevation of ambient temperature of the film sample. Both dielectric constant ε₁ and loss ε₂ increase with the rise of temperature rising and decrease with frequency. The computation of the dielectric modulus M^/ and M^// revealed that the interfacial is the most suitable polarization type.