高效液相色谱-大气压化学电离质谱联用分析天然[口山]酮甙类化合物

利用高效液相色谱大气压化学电离质谱联用技术，探讨了[口山]酮单糖甙和[口山]酮双糖甙在负离子模式下的质谱断裂特点，比较相同条件下不同[口山]酮甙的质谱图，借助[Y0-1]^-和Y0^-离子的相对丰度关系探讨了糖基的性质对断裂规律的影响。同时借助[Y0-1]^-、Y1^-及Z1^-离子的丰度实现对双糖基为1→2与1→6连接的[口山]酮双糖甙的区分。     

Influence of processing conditions on the thermal decomposition of SrTiO<Subscript>3</Subscript> precursors

The present work investigates the influence of milling and calcination atmosphere on the thermal decomposition of SrTiO3 powder precursors. Both pure and neodymium-modified SrTiO3 samples were studied. Milling did not significantly influence numerical mass loss value, but reduced the number of decomposition steps, modifying the profiles of the TG and DTA curves. On the other hand, milling increases the amount of energy liberated by the system upon combustion of organic matter. It was also observed that the milling process, associated to the calcination in an oxygen atmosphere, considerably decreases the amount of organic matter and increases the final mass loss temperature.     

Mathematical models of environmental forecasting

A technique of environmental forecasting with allowance for climate-related factors is proposed. For this purpose, a set of subspaces ranked in terms of disturbance scales is chosen by means of orthogonal decomposition from multidimensional multicomponent databases containing information on the functions of state that describe atmospheric processes for a long period. The leading part of subspaces that take into account climate-scale processes composes an informative basis for hydrodynamic background formation in calculating the forecast scenarios of changes in atmosphere quality. Calculated scenarios with estimates of atmosphere pollution in the Far East of Russia and at the adjacent territories of China and Korea are presented. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 152–163, May–June, 2007.     

两个自适应光学系统串联校正的控制性能分析

提出了一种用两个自适应光学系统串联校正的方法，这两个自适应光学系统分别采用前馈控制和反馈控制布局，利用一组共用的波前校正器中联起来，分析了这种串联校正方法的控制性能和噪声传递特性，在技术复杂性增加不多的条件下，这种串联结构的整体控制效果比单一系统改善了很多，用实际61单元自适应光学系统上的实验数据进行了仿真，验证了这种方法的有效性。     

Molecular Ionization from Carbon Nanotube Paper

Ambient ionization is achieved by spraying from a carbon nanotube (CNT)‐impregnated paper surface under the influence of small voltages (≥3 V). Organic molecules give simple high‐quality mass spectra without fragmentation in the positive or negative ion modes. Conventional field ionization is ruled out, and it appears that field emission of microdroplets occurs. Microscopic examination of the CNT paper confirms that the nanoscale features at the paper surface are responsible for the high electric fields. Raman spectra imply substantial current flows in the nanotubes. The performance of this analytical method was demonstrated for a range of volatile and nonvolatile compounds and a variety of matrices.     

Analysis of questioned documents: A review

During the last years (2000–2014), many publications concerning the forensic analysis of questioned documents have been published, and new techniques and methodologies are nowadays employed to overcome forensic caseworks. This article reviews a comprehensive collection of the works focused on this issue, including dating studies, the analysis of inks from pens and printers, the analysis of paper, the analysis of other samples related to questioned documents and studies on intersecting lines. These sections highlight the most relevant analytical studies by a wide range of analytical techniques. Separation and spectrometric techniques are critically discussed and compared, emphasizing the advantages and disadvantages of each one. Finally, concluding remarks on the research published are included.     

Mass spectrometry imaging of small molecules from live cells and tissues using nanomaterials

We review recently developed methods for analyzing live cells and tissues in ambient conditions without the use of harsh chemical fixation or physical freezing and drying. The first method is based on laser ablation in atmospheric pressure assisted by atmospheric pressure plasma and nanomaterials such as nanoparticles and graphene to enhance laser ablation. The second method is based on secondary ion mass spectrometry imaging of live cells in solution capped with single-layer graphene to preserve intact and hydrated biological samples even under ultrahigh vacuum for secondary ion mass spectrometry bio-imaging in solution with subcellular spatial resolution. Mass spectrometry imaging of small molecules from live cells and tissues can provide an innovative molecular imaging methodology for several biomedical and material research applications.     

第二类拓扑外尔半金属WP2高压超导相的常压截获

第二类拓扑外尔半金属WP₂高压下发生超导转变,然而,高压超导相能否在常压截获还没有相关报道.本文对密封于金刚石对顶砧中的WP₂高压超导相在室温条件下快速卸压至不同压强,原位测量电阻-温度曲线,验证能否在常压截获高压超导相.研究表明：WP₂的高压超导相可以在常压截获,从而提供了一个通过角分辨光电子能谱和扫描隧道谱探寻马约拉纳零能模的拓扑超导体材料平台.     

Au/α-Fe2O3 催化剂存贮失活环境因素及机理分析

 采用沉积沉淀法制备了 CO 低温氧化催化剂 Au/α-Fe₂O₃, 通过 X 射线衍射、X 射线光电子能谱、N₂ 吸附-脱附、傅里叶变换红外光谱、H₂ 程序升温还原和 CO₂ 程序升温脱附等手段对催化剂进行了表征, 探讨了在室温大气气氛下光线照射以及表面吸附等环境因素所导致的催化剂存贮失活及其作用机理. 结果表明, 经 110 ^oC 干燥的 Au/α-Fe₂O₃催化剂表面同时存在 Au³⁺和 Au^δ+ (0 ≤ δ ≤ 1) 物种, 且前者催化 CO 氧化的活性更高; 在室温大气气氛下, 紫外线照射会引起 Au³⁺的还原和 Au 颗粒的生长, 导致催化剂的不可逆失活. 此外, 空气中的 H₂O 和 CO₂ 可同时吸附在 α-Fe₂O₃的表面, 形成表面碳酸盐物种, 会引起催化剂的可逆失活.