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1.
2.
A nanoscale
multivalent platinum drug based on a poly(amidoamine) [PAMAM] dendrimer (generation
4.5, carboxylate surface) has been synthesized and fully characterized using
a variety of spectroscopic, chromatographic and thermal methods. Treatment
of the dendrimer with an aqueous solution containing an excess diaquo(cis-1,2-diaminocyclohexane)platinum(II) produces
a conjugate containing approximately forty (diaminocyclohexane)platinum(II)
moieties at the surface of the dendrimer. This material undergoes smooth two-stage
thermal decomposition to provide residual platinum oxide reflecting the platinum
loading in the drug. 相似文献
3.
General purpose poly(styrene) is a large
volume commodity polymer widely used in a range of applications. For many
of these the presence of an additive to impart some flammability resistance
is required. Most commonly, brominated aromatics are used for this purpose.
As the polymer undergoes combustion these compounds decompose to generate
bromine atoms and/or hydrogen bromide which escape to the gas phase and trap
flame propagating radicals. While these species are effective in inhibiting
flame propagation they present the opportunity for loss of halogen to the
atmosphere. For this reason, the use of these compounds is being limited in
some parts of the world. Phosphorus compounds, on the other had, impart a
flame retarding influence by promoting char formation at the surface of the
burning polymer. This prevents heat feedback to the polymer and consequent
pyrolysis to generate fuel fragments. The combination of both bromine and
phosphorus present in a single compound might generate a superior flame-retarding
additive in that both modes of retardancy might be promoted simultaneously.
Should this be the case smaller amounts of additive might be necessary to
achieve a satisfactory level of flame retardancy. A series of such additives,
brominated aryl phosphates, has been synthesized and fully characterized spectroscopically.
Blends of these additives, at various levels, with poly(styrene) have been
examined by DSC, TG and in the UL-94 flame test. The flammability of the polymer
is dramatically diminished by the presence of the additive. 相似文献
4.
硅基材料是新一代高容量锂离子蓄电池负极材料的典型代表,近年来已成为理论研究和应用研究的热点.本文介绍了锂离子电池硅基负极材料的制备方法、电化学性能及其研究现状,分析了硅材料作为锂离子电池负极材料存在的问题;讨论了硅材料作为锂离子电池负极材料的研究前景.并指出若能克服目前存在问题,将有望成为新一代锂离子电池负极材料. 相似文献
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7.
The filtration performance of yeast cell harvesting was greatly improved by using an oscillatory flow mixing technique in both tubular and flat sheet membrane systems; flux increases of several fold were achieved. The effects of various operating parameters such as frequency, amplitude and ratio of net forward flow rate to oscillatory flow rate were investigated. A simple alternative to the dual head pump, which involved the use of solenoid valves for producing flow reversal, was developed. The flux was significantly increased using this new operating mode. As the only increase of power consumption was from inertia loss due to change of flow direction the additional power consumption is minimal. 相似文献
8.
The Raman and electron impact mass spectra of synthetic indigo and its four 6,6'-dihalogeno analogues are reported and discussed. The influence of varying the halogen on these Raman spectra is considered. Particular emphasis is laid on distinguishing indigo from 6,6'-dibromoindigo and differentiating between the dihalogenocompounds, so as to develop protocols for determining whether artefacts are coloured with dyes of marine or terrestrial origin and whether such artefacts are dyed with genuine "Tyrian Purple" or with dihalogenoindigo substitutes that do not contain bromine. The value of even low resolution electron impact mass spectrometry in a forensic context as a means of identifying authentic 6,6'-dibromoindigo and distinguishing it from its dihalogenoanalogues is emphasised 相似文献
9.
Antonio Doménech María Teresa Doménech‐Carbó Howell G. M. Edwards 《Electroanalysis》2007,19(18):1890-1900
Multivariate chemometric methods are applied for identifying earth pigments from square‐wave voltammetric measurements performed at pigment‐modified paraffin‐impregnated graphite electrodes allowing for a separation between hematite‐based earths, French ochres, Spanish ochres, siennas, umbers and green earths. This methodology is applied to the identification of the pigments in samples from the ceiling frescoes of Antonio Palomino (dated 1707) in the vaulted nave of the Sant Joan del Mercat church in Valencia (Spain). These frescoes suffered considerable damage by fire during the Spanish Civil War in 1936, resulting in severe chemical and chromatic alterations. Electrochemical data, supported by scanning electron microscopy/energy dispersive X‐ray microanalysis and Raman spectroscopy, indicate that thermal stress induced the transformation of goethite‐based yellow ochres into hematite and magnetite. 相似文献
10.
So RC Ndonye R Izmirian DP Richardson SK Guerrera RL Howell AR 《The Journal of organic chemistry》2004,69(9):3233-3235
Sphinganines can be synthesized in just three steps from easily prepared serine-derived Weinreb amide 4. Pre-deprotonation of the acidic (N-H and O-H) protons of 4 allows for its efficient conversion to amino ketones 5. Such ketones can be selectively reduced to either erythro- or threo-sphinganines. Partially protected sphinganines 11 are also readily accessible in five steps from 4. Thus, Weinreb amide 4 represents one of the most versatile templates described to date for sphinganine synthesis. 相似文献