气相沉积TiN和Ti（C,N）镀层的热磨损性能

气相沉积法制取的ＴｉＮ和Ｔｉ（Ｃ，Ｎ）镀层在室温工作的磨损部件上得到了广泛的应用，但对其在高温下的磨损性能之研究却还很少。为了探讨其在高温磨损下应用的可行性，利用ＳＲＶ滑动摩擦磨损试验机和改进型Ｔｉｔｔａｇａｌａ热冲击磨损试验机，对以热作模具钢３Ｃｒ２Ｗ８Ｖ为基体的气相沉积的ＴｉＮ和Ｔｉ（Ｃ，Ｎ）硬质镀层的热磨损性能进行了试验研究，同时还通过多种表面分析手段对膜基体系的失效机制作了观测与讨论，结果表明，ＴｉＮ和Ｔｉ（Ｃ，Ｎ）镀层都具有良好的高温耐磨性，在８５０℃以上的高温条件下，几种有镀层试样的热冲击磨损量都明显地比无镀层３Ｃｒ２Ｗ８Ｖ试样的低。ＳＲＶ高温滑动摩擦磨损试验发现，镀层的高温软化和氧化都不明显；只有当膜基界面结合不良或膜基体系的承载能力不足时，才会发生镀层的剥落或碎裂。     

Proposal for a nuclear light source

This study considers a principal possibility of creating a nuclear light source of the vacuum ultra violet (VUV) range based on the \begin{document}$ ^{229} $\end{document}Th nucleus. This nuclear light source can help solve two main problems — excitation of the low-lying \begin{document}$ ^{229m} $\end{document}Th isomer and precision measurement of the nuclear isomeric transition energy. The thorium nuclear light source is based on the nuclei implanted in a thin dielectric film with a large bandgap. While passing an electric current through the sample, the \begin{document}$ ^{229} $\end{document}Th nuclei are excited to the low energy isomeric state \begin{document}$ 3/2^+(8.19\pm0.12 $\end{document} eV) through the process of inelastic scattering of conduction electrons. The subsequent spontaneous decay of \begin{document}$ ^{229m} $\end{document}Th is followed by the emission of γ quanta in the VUV range. The luminosity of the thorium nuclear light source is approximately \begin{document}$ 10^5 $\end{document} photons/s per 1 A of current, per 1 ng of \begin{document}$ ^{229} $\end{document}Th. The suggested scheme to obtain γ radiation from the \begin{document}$ ^{229m} $\end{document}Th isomer can be considered as a type of nuclear analogue of the optical radiation from the usual metal-insulator-semiconductor (MIS) junction.     

D-Sorbitol Physical Properties Effects on Filaments Used by 3D Printing Process for Personalized Medicine

Fused filament fabrication (FFF) is a process used to manufacture oral forms adapted to the needs of patients. Polyethylene oxide (PEO) filaments were produced by hot melt extrusion (HME) to obtain a filament suitable for the production of amiodarone hydrochloride oral forms by FFF 3D printing. In order to produce personalized oral forms adapted to the patient characteristics, filaments used by FFF must be controlled in terms of mass homogeneity along filament. This work highlights the relation between filament mass homogeneity and its diameter. This is why the impact of filler excipients physical properties was studied. It has been showed that the particle’s size distribution of the filler can modify the filament diameter variability which has had an impact on the mass of oral forms produced by FFF. Through this work it was shown that D-Sorbitol from Carlo Erba allows to obtain a diameter variability of less than 2% due to its unique particle’s size distribution. Using the filament produced by HME and an innovating calibration method based on the filament length, it has been possible to carry out three dosages of 125 mg, 750 mg and 1000 mg by 3D printing with acceptable mass uniformity.     

Probing single molecules and molecular aggregates: Raman spectroscopic advances

Development of Raman spectroscopy, profiting from surface‐enhanced Raman scattering and tip‐enhanced Raman scattering techniques, has inspired extensive research interest for trace analysis and dynamic measurements up to single‐molecule level. For another, Raman spectroscopy has also been recognized of significance in solving some important issues relating to molecule aggregates in chemistry and biology, owing to the capability of non‐destructive detection and high‐resolution fingerprints by which molecules and their aggregates can be identified. Herein, we summarize the recent progress of Raman spectroscopy in probing single molecules and molecular aggregates and block out a future prospective of Raman spectroscopy applied in cluster science. Copyright © 2015 John Wiley & Sons, Ltd.     

Hydrated Electron Transfer to Nucleobases in Aqueous Solutions Revealed by Ab Initio Molecular Dynamics Simulations

We present an ab initio molecular dynamics (AIMD) simulation study into the transfer dynamics of an excess electron from its cavity‐shaped hydrated electron state to a hydrated nucleobase (NB)‐bound state. In contrast to the traditional view that electron localization at NBs (G/A/C/T), which is the first step for electron‐induced DNA damage, is related only to dry or prehydrated electrons, and a fully hydrated electron no longer transfers to NBs, our AIMD simulations indicate that a fully hydrated electron can still transfer to NBs. We monitored the transfer dynamics of fully hydrated electrons towards hydrated NBs in aqueous solutions by using AIMD simulations and found that due to solution‐structure fluctuation and attraction of NBs, a fully hydrated electron can transfer to a NB gradually over time. Concurrently, the hydrated electron cavity gradually reorganizes, distorts, and even breaks. The transfer could be completed in about 120–200 fs in four aqueous NB solutions, depending on the electron‐binding ability of hydrated NBs and the structural fluctuation of the solution. The transferring electron resides in the π*‐type lowest unoccupied molecular orbital of the NB, which leads to a hydrated NB anion. Clearly, the observed transfer of hydrated electrons can be attributed to the strong electron‐binding ability of hydrated NBs over the hydrated electron cavity, which is the driving force, and the transfer dynamics is structure‐fluctuation controlled. This work provides new insights into the evolution dynamics of hydrated electrons and provides some helpful information for understanding the DNA‐damage mechanism in solution.     

二氮杂菲分光光度法分析温泉水中铁的价态

使用UV–2100型分光光度计,在二氮杂菲质量浓度为1 g/L、乙酸铵缓冲溶液(pH 4.2)用量为10 m L、显色时间为15 min的条件下,于510 nm处对温泉水中铁的价态进行分析。Fe(Ⅱ)测定结果的相对标准偏差为1.61%(n=20),被测温泉水中总铁加标回收率为98.42%~104.36%,Fe(Ⅱ)的加标回收率为95.25%~102.88%。该法可用于温泉水中铁的价态分析。     

Synthesis of colloidal NiO nanocrystals by a hot‐injection approach with a protecting ligand

We synthesize small and uniform NiO nanocrystals, which can be potential for hole‐transporting of organic solar cells and transparent conducting material, based on a protecting ligand of lithium stearate by a hot‐injection method. And the reaction mechanism is alcoholysis of metal carboxylate salts with the protection ligand of lithium stearate binding to the surfaces of NiO nanocrystals to prevent them reduction into Ni. We find that the hot‐injection method is an effective way to prepare narrow size distribution and small size of NiO nanocrystals. The relatively superior optical transparency and flat surface features of the NiO nanocrystal thin films are also obtained.     

Low-energy electron scattering from gaseous CS<Subscript>2</Subscript>: angular distributions and effect of exchange forces

Ab initio calculations are reported for the quantum scattering of electrons from CS₂ molecules in the gas phase and for energies which range from near threshold up to about 100 eV. Angular distributions are examined in detail and an extensive comparison is made with existing experiments and earlier calculations. The agreement found with the latter data is fairly good and results are further discussed in terms of a physical mechanism of “exchange level shifting" to explain the disappearance of a Π_u resonance suggested by earlier studies.     

Magnetic anisotropy and electronic structure of iron films on W(1 1 0) by spin-polarized two-electron spectroscopy

Low-energy spin-polarized two-electron spectroscopy was applied to study the spin-dependent electronic structure of 3 ML and 50 ML epitaxial iron films grown on single crystal W(1 1 0). Such films are known to show an in-plane rotation of the easy magnetization axis between thicknesses [M. Donath, Journal of Physics: Condensed Matter 11 (48) (1999) 9421; D. Sander, Journal of Physics: Condensed Matter (20) (2004) R603, O. Fruchart, J.P. Nozieres, D. Givord, Journal of Magnetism and Magnetic Materials 207 (1999) 158, H.J. Elmers, U. Gradmann, Applied Physics A: Materials Science & Processing 51 (3) (1990) 255]. Momentum distributions of correlated electron pairs I(k₁, k₂) excited from the films by 25 eV primary electrons were measured for two opposite polarizations of the incident beam. Energy and momentum conservation laws in the electron scattering events allow the extraction of information on the spin-dependent Bloch spectral density function of the valence electrons in iron films. The observed difference in the electronic structure of these two films is most likely due to the different crystal structures of the films.