水和白酒中异味物质检测的研究进展

综述了水和白酒中异味物质检测的样品前处理方法(包括液液萃取、固相萃取、液相微萃取、固相微萃取、搅拌棒吸附萃取、吹扫捕集、顶空等)和检测方法(包括气相色谱法、气相色谱-质谱法、气相色谱-飞行时间质谱法)的研究进展(引用文献52篇)。     

双金属氮化物Co3W3N/CNTs纳米复合材料的制备及其室温常压氮还原性能

采用水热法并经氨气保护热处理制备了双过渡金属氮化物Co3W3N/CNTs复合材料,得到了价格低廉且拥有良好氮电化学还原性能(NRR)的催化剂。通过调节已经预氧化的CNTs与过渡金属氮化物前驱体CoWO4的比例以及氨气热处理温度,实现了Co3W3N在CNTs表面的均匀负载。扫描电子显微镜(SEM)及透射电子显微镜(TEM)测试结果显示该电化学活性纳米微粒均匀地分散于CNTs表面,表明经预氧化的CNTs由于表面富集了较多的活性基团,有利于双过渡金属氮化物的分散生长。热处理后CNTs表面的Co3W3N微粒尺寸约为20 nm,相较于无载体的Co3W3N尺寸(100 nm)有明显减小。室温条件下,在N2饱和的0.01 mol·L^-1 H2SO4溶液中测试了该纳米复合材料在不同过电位下的NRR,该材料在-0.3 V(vs RHE)时的产氨率及法拉第效率分别可达12.73μg·h^-1·cm-2和13.59%,对比同样条件下,纯相Co3W3N的产氨率及法拉第效率仅为1.08μg·h^-1·cm^-2和1.76%。结果表明,通过水热反应和氨气保护热处理的Co3W3N/CNTs纳米复合材料具有良好的NRR性能。     

利用循环伏安法模拟技术理解电极过程可逆性**

循环伏安法测定电极过程可逆性实验在仪器分析实验中有着重要的意义。现行的实验设计中一般将铁氰化钾作为氧化还原反应研究的对象。由于铁氰化钾/亚铁氰化钾的氧化还原过程在电化学上可逆,学生通过实验很难理解电化学不可逆的过程,不易区分可逆和不可逆过程。本文利用循环伏安模拟的方法,通过改变电子转移速率常数(k0),得到不同的循环伏安谱图,结合课本上对于可逆性的判据(Epa-Epc=0.056 V/n,ipaipc≈-1)来解释不同的电子转移速率对于电极过程可逆性的影响。     

具有界时滞和分布时滞的反应扩散神经网络的指数同步

本文研究了一类具有界时滞和分布时滞的反应扩散神经网络的状态变量在边界为零的条件下驱动系统和响应系统的指数同步性,得到了其驱动系统和响应系统指数同步的充分条件。     

Anomalous magnetic properties of an iron film system deposited on fracture surfaces of α-Al2O3 ceramics

An iron film percolation system is fabricated by vapour-phase deposition on fracture surfaces of α-Al2O3 ceramics. The zero-field-cooled （ZFC） and field-cooled （FC） magnetization measurement reveals that the magnetic phase of the film samples evolve from a high-temperature ferromagnetic state to a low-temperature spin-glass-like state, which is also demonstrated by the temperature-dependent ac susceptibility of the iron films. The temperature dependence of the exchange bias field He of the iron film exhibits a minimum peak around the temperature T=5 K, which is independent of the magnitude of the cooling field Hcf. However, for T 〉 10K, （1） He is always negative when Hcf=2kOe and （2） for Hcf= 20 kOe （1Oe≈80 A/m）, He changes from negative to positive values as T increases. Our experimental results show that the anomalous hysteresis properties mainly result from the oxide surfaces of the films with spin-glass-like phase.     

Cavity-enhanced laser cooling of solid-state materials in a standing-wave cavity

We propose a new method to cool the yb^3＋-doped ZBLANP glass in a standing-wave cavity. There are two advantages of this cavity-enhanced technique： the pumping power is greatly enhanced and the absorption of the cooling material is greatly increased. We introduce the basic principle of the cavity-enhanced laser cooling and discuss the cooling effect of a solid-state material in a cavity. From the theoretical study, it is found that the laser cooling effect is strongly dependent on the reflectivity of the cavity mirrors, the length of the solid material, the surface scattering of the material, and so on. Some optimal parameters for efficient laser cooling are obtained.     

Preparation and characterization of SiO_2/TiO_2/methylcellulose hybrid thick films for optical waveguides

Optical-quality films of a few μm thickness are a basic re- quirement for integrated optics[1-3]. Since such films are thick by normal coating standards, a number of special- ized methods have been developed to form them. The sol-gel processing is one approach because of the high optical quality of materials produced and freedom to im- pregnate them with a variety of additives to modify their optical characteristics. It is a popular and widespread technique for preparing coating films in labo…     

Dynamical Lie algebra method for highly excited vibrational state of asymmetric linear tetratomic molecules

The highly excited vibrational states of asymmetric linear tetratomic molecules are studied in the framework of Lie algebra. By using symmetric groupU ₁(4)U ₂(4)⊗U ₃(4), we construct the Hamiltonian that includes not only Casimir operators but also Majorana operators M₁₂, M₁₃ and M₂₃, which are useful for getting potential energy surface and force constants in Lie algebra method. By Lie algebra treatment, we obtain the eigenvalues of the Hamiltonian, and make the concrete calculation for molecule C₂HF.     

衬底对Cu(In,Ga)Se2薄膜织构的影响

分别在苏打石灰玻璃、Mo箔、无择优取向的Mo薄膜以及(110)择优取向的Mo薄膜四种不同衬底上，采用共蒸发工艺沉积约2 μm厚的Cu(In,Ga)Se₂薄膜，用X射线衍射仪测量薄膜的织构，研究衬底对Cu(In,Ga)Se₂薄膜织构的影响.在以上四种衬底上沉积的Cu(In,Ga)Se₂薄膜的(112)衍射峰强度依次逐渐减弱，(220/204)衍射峰从无到有且强度逐渐增强.在苏打石灰玻璃和Mo箔衬底上的Cu(In,Ga)Se_{2关键词： 择优取向 Cu(In 2}薄膜')" href="#">Ga)Se₂薄膜 太阳电池     

固体材料反斯托克斯荧光制冷的理论研究及其最新进展

本文首先回顾了反斯托克斯荧光制冷的历史发展,简单讨论了激光制冷的循环过程及其制冷条件;其次,概述了反斯托克斯Raman散射、反斯托克斯荧光制冷的热力学理论和热力学限制,重点介绍了适用于各种制冷材料(如稀土离子掺杂玻璃、半导体和晶体等)反斯托克斯荧光制冷研究的理论模型,并简单讨论了激光制冷实验中各种测量温度变化的实验方法及其基本原理。最后,就反斯托克斯荧光制冷的一种最新应用及其前景进行了简单介绍与展望。