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51.
52.
Janina Sroka-Markovic Linda Johansson Magnus B. O. Andersson Ingrid Granelli 《Chromatographia》2012,75(7-8):329-336
Development of a reversed phase high performance liquid chromatographic method for determination of six related impurities in prilocaine substance is reported. The test of related impurities in European Pharmacopoeia (Ph. Eur.) cannot meet the demands with the chromatographic parameters given, therefore different types of chromatographic systems and eight columns have been evaluated in the present study. A new method with a Hypercarb column was developed and validated. This method fulfils the demands in the Ph. Eur., and the validation shows that the method is selective, reproducible, linear, accurate and robust with sufficient limits of detection (0.001–0.004% of 2.5?mg prilocaine mL?1) and quantification (0.002–0.009% of 2.5?mg prilocaine mL?1). 相似文献
53.
Janina Kabatc Beata Jdrzejewska Jerzy Pczkowski 《Journal of polymer science. Part A, Polymer chemistry》2000,38(13):2365-2374
A series of cyanine butyltriphenylborate salts were prepared and tested as initiators of free‐radical polymerization photoinitiated via a photoinduced electron‐transfer process. For the majority of the tested series, the highest rate of photoinitiated free‐radical polymerization was observed when sec‐butyl radicals were formed. Essentially, there was no influence of the quantum yield of the free‐radical formation on the rate of the free‐radical polymerization initiated by the cyanine‐borate salts. The experimental data revealed that the relationship between the rate of polymerization and the free energy change for the electron transfer displayed typical Marcus region kinetic behavior. The photoreduction of the cyanine butyltriphenylborate salts produced colorless products. The efficiency of the bleached‐dye formation had no effect on the overall efficiency of photoinitiated polymerization. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2365–2374, 2000 相似文献
54.
Micha W. Wieczorek Wiesaw R. Majzner Renata Kaczmarek Janina Baraniak Wojciech J. Stec 《Heteroatom Chemistry》1998,9(2):271-279
Two isomeric pairs of compounds, cis- and trans-2-morpholino-2-thiono-4-methyl-1,3,2-dioxaphosphinane ( 1A + 1B ) and 2-morpholino-2-oxo-4-methyl-1,3,2-dioxaphosphinane ( 2A + 2B ) were obtained and separated into the pure compounds by silica gel chromatography. Attempts at crystallization afforded 1A , 1B , and 2B . Each crystalline isomer was studied by the X-ray technique, and each crystal and molecular structures assigned. These studies revealed that 1B and 2B have exocyclic 4-CH3 and sulfur (for 1B ) or 4-CH3 and oxygen (for 2B ) in the diequatorial position (cis-geometry), while compound 1A possesses the 4-CH3 group in equatorial position while sulfur is in an axial position (trans-geometry). For all the examined compounds, all the basic geometrical parameters, such as bond lengths, bond and torsion angles, and the deformation of a chair conformation of the six-membered heterocyclic rings, have been established. Such unambiguous assignment of cis-trans geometry in both pairs of 1 and 2 allowed us to confirm the stereoretentive PS → PO conversion by means of OXONE® and the stereoinvertive mechanism of formic-acid catalyzed hydrolysis of phosphorothiomorpholidates. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:271–279, 1998 相似文献
55.
Dr. Xin Chen Malte Kohring Dr. M'hamed Assebban Dr. Bartłomiej Tywoniuk Dr. Cian Bartlam Narine Moses Badlyan Prof. Janina Maultzsch Prof. Georg S. Duesberg Prof. Heiko B. Weber Dr. Kathrin C. Knirsch Prof. Andreas Hirsch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(52):13117-13122
The development of an efficient method to patterning 2D MoS2 into a desired topographic structure is of particular importance to bridge the way towards the ultimate device. Herein, we demonstrate a patterning strategy by combining the electron beam lithography with the surface covalent functionalization. This strategy allows us to generate delicate MoS2 ribbon patterns with a minimum feature size of 2 μm in a high throughput rate. The patterned monolayer MoS2 domain consists of a spatially well-defined heterophase homojunction and alternately distributed surface characteristics, which holds great interest for further exploration of MoS2 based devices. 相似文献
56.
In a space-time of two dimensions the overall effect of the collision of two solitons is a time delay (or advance) of their final trajectories relative to their initial trajectories. For the solitons of affine Toda field theories, the space-time displacement of the trajectories is proportional to the logarithm of a number X depending only on the species of the colliding solitons and their rapidity difference. X is the factor arising in the normal ordering of the product of the two vertex operators associated with the solitons. X is shown to take real values between 0 and 1. This means that, whenever the solitons are distinguishable, so that transmission rather than reflection is the only possible interpretation of the classical scattering process, the time delay is negative and so an indication of attractive forces between the solitons. 相似文献
57.
In this paper the quantum heat transport equation (QHT) is applied to the study of thermal properties of Planck gas, i.e.,
a gas of massive particles with mass equal to the Planck massM
P
= (łc/G)1/2 and whose relaxation time equals the Planck timeτ
p
= (łG/c
5)1/2. The quantum of thermal energy for a Planck gas,E
Planck = 1019GeV, and the quantum thermal diffusion coefficientD
Planck = (ħG/c)1/2 are calculated. Within the framework of QHT the thermal phenomena in a Planck gas can be divided into two classes: for a
time period shorter thanτ
p
, the time reversal symmetry holds and for a time period longer thanτ
p
, time symmetry is broken, i.e., a time arrow is created. 相似文献
58.
59.
Janina Kuduk-Jaworska Maria Kubiak Tadeusz Gŀowiak Henryk Mastalarz 《Transition Metal Chemistry》1994,19(4):403-405
Summary A new platinum complex of 1-methyl-5-nitroimidazole has been obtained and characterized by elemental analysis, i.r. and n.m.r. spectroscopy. The structure of [PtI2-(C4 H5N3O2)2] has been determined by single-crystal X-ray diffraction. The crystals are triclinic: P1, a = 15.640(3), b = 12.617(2), c = 6.701(1) , = 102.77(5), = 101.15(5), = 100.71(5)°, V = 1228.6(3) 3, Z = 3, Dx = 2.851(6) Mg m–3, (MoK
) = 0.71069 , = 12.85 mm–, F(000) = 948, final R = 0.038 for 2859 reflections. The complex consists of monomeric PtI2(1-methyl-5-nitroimidazole)2 units. The coordination geometry is square-planar. The two 1-methyl-5-nitroimidazole ligands are trans coordinated to platinum. 相似文献
60.
An analysis of the influence of I? ions on radiative and radiationless transitions from the lowest triplet state of aromatic hydrocarbons is presented. The distance dependence in the external heavy atom effects and the dependence of the enhancement of the T1→S0 radiative transition on the triplet energy is discussed in terms of perturbation theory. 相似文献