High lithium conductivities in weakly-ionophilic low-dimensional block copolymer electrolytes

The structure of amphiphilic low-dimensional copolymer electrolytes I of similar overall composition but prepared by different synthetic procedures X and Y are described. I are copolymers of poly[2,5,8,11,14-pentaoxapentadecamethylene(5-alkyloxy-1,3-phenylene)] (CmO5) and poly[2,-oxatrimethylene(5-alkyloxy-1,3-phenylene)] (CmO1) where the alkyl side chains having m carbons are hexadecyl or mixed dodecyl/octadecyl (50/50). ¹H NMR shows that the copolymers have 50% (m = 16) or only 18 and 13% of CmO5 units and DSC indicates that the copolymers have ‘block’ sequencing of CmO1 and CmO5 segments. Molecular dynamics modelling indicates that in CmO5 Li⁺ and BF₄⁻ ions are separated by Li⁺ encapsulation in tetraethoxy segments but in ionophobic CmO1 units the salt is mostly present as neutral aggregates decoupled from the polymer. Conductivities of these microphase-separated mixtures with salt-bridge amphiphilic polyethers II and III of each system are similar. They have low temperature dependence over the range 20 °C to 110 °C at ∼10⁻³ S cm⁻¹. ⁷Li NMR linewidth measurements confirm high lithium mobilities at −20 °C. A conduction mechanism is proposed whereby Li⁺ hopping takes place along rows of decoupled aggregates (dimers/quadrupoles) within an essentially block copolymer structure. Subambient measurements to −10 °C gave a conductivity of 4 × 10⁻⁵ S cm⁻¹.     

New unsaturated derivatives of Xanthan gum: Synthesis and characterization

Unsaturated Xanthan derivatives, which can be used for the development of biodegradable three-dimensional networks having hydrogel properties, were prepared by esterification under various conditions. Xanthan gum derivatives with different degrees of substitution were obtained by reaction with an unsaturated organic acid (acrylic acid) or with acid reactive derivatives (acryloyl chloride, maleic anhydride). The presence of acrylate and maleate groups in the modified structure of Xanthan gum was detected by ATR-FTIR, ¹H liquid NMR and ¹H HRMAS NMR spectroscopies. The degree of substitution as determined by ¹H NMR could be controlled by varying the chemical nature of functionalisation agent, reaction time and temperature.The results proved that this polysaccharide can be modified by esterification with acids or unsaturated acid derivatives for further synthesis of hydrogels. Maleic anhydride presents a higher reactivity as compared to acrylic acid and acryloyl chloride.     

松南气田火山岩储层流体性质的识别

利用测井资料识别火山岩储层流体性质一直是困扰测井评价的难题.针对火山岩储层岩石成分、结构和气水关系复杂,孔隙空间分布极不均匀,储层具有很强的非均质性以及低孔、低渗的特点,采用核磁-密度测井综合法、横波(纵波)-合成横波(合成纵波)重叠法、压缩系数-泊松比重叠法及压力梯度法识别松南气田流体性质,取得了较好的效果.研究表明,由于各种测井方法在不同的孔隙-裂缝系统中的响应机制不同,天然气识别的效果存在明显的差异,总结了各类储层的气层识别方法.     

Number of metallic clusters in Y zeolites obtained from129Xe NMR

We present a simple model which permits to obtain the number of metallic clusters entrapped in Y zeolites from the curves of the chemical shifts of¹²⁹Xe NMR against the pressure of Xe. From the metal loading the average number of atoms per cluster can also be calculated. We apply the model to Pt/NaY and the bimetallic Pt-Cu/NaY.     

基于Virtools与Flash的实时交互虚拟NMR实验室

为了实现对核磁共振(NMR)波谱分析实验交互过程的三维虚拟仿真,提出了采用3ds Max建模并通过Virtools及Flash实现交互,建立以虚拟人物为依托、全场景、开放式、三维与二维结合沉浸交互式核磁共振波谱分析虚拟实验室的方法。以多种样品的完整核磁共振实验流程为考察对象,采用VSL编程语言结合BB模块以及FlashActionScript 2.0语言编程的方式实现了实时交互操作与工作站及谱图解析之间的参数信息通信,模拟谱图绘出过程,并且增加了谱图解析过程。该软件实现了样品选择、溶剂选择、局部放大、监控跟踪评价、谱图绘出以及谱图解析功能,完整的模拟并了样品核磁共振波谱分析实验的全过程。并增强了功能性。     

核磁共振谱仪锁线故障分析与排除

对德国ＢＲＵＫＥＲ公司ＡＣ、ＡＭ系列核磁共振谱仪锁线故障进行了分类，分析了各故障的产生原因，阐述了排除过程。     

(E)-3,5,4’-三羟基联苯乙烯的NMR谱分析

本工作利用包括~1H NMR、APT(Attached Proton Test)、HMBC等NMR技术对(E)-3,5,4(?)-三羟基联笨乙烯的NMR谱学特征进行分析。该化合物结构简单,但高度对称,所含质子个数相时较少,结构解析有一定的难度。本工作对实验谱的内含信息进行挖掘,并对其谱学特征(包括某些实验的"缺陷")进行分析,最终完成该化合物的NMR结构解析。     

分数维在水泥石孔隙研究中的应用

孔隙是水泥石中不可或缺的一相,并对其宏观的物理化学性能产生重要的影响。在阐述分数维的基础上,分析了水泥石孔隙的分数维,介绍了HIP和小角度x衍射两种测试水泥石分数维的方法及其研究现状。     

wPMLG-5 Spectroscopy of Self-Aggregated BChl e in Natural Chlorosomes of Chlorobaculum Limnaeum

¹H magic angle spinning (MAS) nuclear magnetic resonance (NMR), employing rapid spinning and the wPMLG-5 pulse sequence, was used to explore the possibility for performing ¹H solid state NMR of a light-harvesting organelle, the chlorosome antenna of Chlorobaculum limnaeum. This natural antenna system is built from bacteriochlorophyll e (BChl e) molecules that are self-assembled to form a supramolecular scaffold for in vivo harvesting of light. We present preliminary data on this chlorosome species and address the feasibility of performing wPMLG spectroscopy, in terms of high power irradiation on a fragile biological sample. In parallel, enhancing the ¹H shift dispersion from the magnetic field can help to resolve signals from protons that resonate downfield. Different line narrowing mechanisms operating in parallel provide access to resolving selected ¹H signals collected from the moderately sized and chemically diverse BChl e molecular motif in the chlorosome scaffold. These discoveries will be helpful for future studies of structural and functional characteristics of self-assembled natural and artificial light-harvesting molecules.     

The Laboratory Founded by Van der Waals

During the past century, the Van der Waals Laboratory at the University of Amsterdam has been the principal provider of reliable fluid property data over large ranges of pressure and temperature. This paper describes the history of the laboratory, starting in 1898 when funding for it was obtained. In the early period, under Van der Waals and Kohnstamm, the high-pressure direction was chosen, and the first PVT and phase equilibria data were published. The main focus of this paper is the Michels period, from 1921 to 1960. In this period, the laboratory acquired its own building and assumed a unique position in the world because of its highly accurate thermodynamic, transport, and other property measurements in fluids at high pressures. In the 1950s, a second laboratory was built by Michels at the University of Maryland, per request of the U.S. Navy. Under Trappeniers, 1961–1987, the laboratory incorporated new techniques, such as NMR, undertook a major expansion of the pressure range, and extended its interest to phase transitions in molecular solids. The position of the Van der Waals Laboratory in the world of high-pressure science is highlighted.