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601.
T. Jankowski 《Acta Mathematica Hungarica》2003,100(4):329-342
Integro-differential inequalities with initial time difference arediscussed. They play an important role in the investigation
of initial value problems of integro-differential equations where the initial time differs. The existence of extremal solutions
is investigated by the monotone iterative technique.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
602.
Oleg Kadkin Karol Osajda Piotr Kaszynski Thomas A. Barber 《Journal of polymer science. Part A, Polymer chemistry》2003,41(8):1114-1123
The composition of polyester polyols derived from terephthalic acid (TPA) and diethylene glycol (DEG) was examined. The synthesis of individual oligomers 1 , n is described. The compounds were characterized with 1H and 13C NMR, mass spectrometry, and elemental analyses. The resonance signals arising from aromatic protons in 1 , n = 1–3 were identified in 1H NMR spectra of TPA‐DEG condensates. From 1H NMR studies and chromatographic separation, it was concluded that the condensation of TPA and DEG in a 1:2 molar ratio results in a mixture of linear oligomers 1 with the average ñ varying from 1.1 to 2.2, and containing about 2% of cyclic oligomer 2 . © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1114–1123, 2003 相似文献
603.
Tadeusz Jankowski 《Journal of Mathematical Analysis and Applications》2004,291(2):605-624
Some comparison results for delay integro-differential inequalities starting from different initial points are formulated. The monotone iterative technique is applied to formulate sufficient conditions for existence of extremal solutions of delay integro-differential equations with initial time difference. 相似文献
604.
Jozef Martinka Filip Martinka Peter Rantuch Ivan Hrušovský Lenka Blinová Karol Balog 《Journal of Thermal Analysis and Calorimetry》2018,131(2):899-906
This study deals with heat of combustion of selected fast-growing woods. The study also investigates the impact of heat flux on fire risk of the selected fast-growing woods. The hybrid poplar J-105 (Populus nigra × P. maximowiczii), white willow (Salix alba L.) and black locust (Robinia pseudoacacia L.) woods were measured. The heats of combustion were determined by a bomb calorimeter. Fire risk was evaluated with a cone calorimeter at different heat fluxes. The net heat of combustion occurred in the interval from 17.68 MJ kg?1 (black locust) to 18.02 MJ kg?1 (hybrid poplar). Fire risk was assessed on the basis of the critical heat flux, maximum average rate of heat emission, carbon monoxide yield, smoke yield and time to flashover. The hybrid poplar had the lowest critical heat flux (12.8 kW m?2), and the white willow had the highest critical heat flux (17.4 kW m?2). The maximum average rate of heat emission and the smoke yield increased with the increasing heat flux. On the other hand, carbon monoxide yield decreased with the increasing heat flux. The differences between the times to flashover of the measured wood species were not significant. 相似文献
605.
606.
19F NMR Spectroscopy as a Highly Sensitive Method for the Direct Monitoring of Confined Crystallization within Nanoporous Materials
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Karol P. Nartowski Diksha Malhotra Dr. Lucy E. Hawarden Dr. Juraj Sibik Dr. Dinu Iuga Dr. J. Axel Zeitler Dr. László Fábián Prof. Yaroslav Z. Khimyak 《Angewandte Chemie (International ed. in English)》2016,55(31):8904-8908
The introduction of fluorine into the structure of pharmaceuticals has been an effective strategy for tuning their pharmacodynamic properties, with more than 40 new drugs entering the market in the last 15 years. In this context, 19F NMR spectroscopy can be viewed as a useful method for investigating the host–guest chemistry of pharmaceuticals in nanosized drug‐delivery systems. Although the interest in confined crystallization, nanosized devices, and porous catalysts is gradually increasing, understanding of the complex phase behavior of organic molecules confined within nanochambers or nanoreactors is still lacking. Using 19F magic‐angle‐spinning NMR spectroscopy, we obtained detailed mechanistic insight into the crystallization of flufenamic acid (FFA) in a confined environment of mesoporous silica materials with different pore diameters (3.2–29 nm), providing direct experimental evidence for the formation of a molecular‐liquid‐like layer besides crystalline confined FFA form I. 相似文献
607.
Michał Marszal Ashesh Saha Krzysztof Jankowski Andrzej Stefański 《The European physical journal. Special topics》2016,225(13-14):2669-2678
We investigate synchronization phenomena in systems of self-induced dry friction oscillators with kinematic excitation coupled by linear springs. Friction force is modelled according to exponential model. Initially, a single degree of freedom mass-spring system on a moving belt is considered to check the type of motion of the system (periodic, non-periodic). Then the system is coupled in chain of identical oscillators starting from two, up to four oscillators. A reference probe of two coupled oscillators is applied in order to detect synchronization thresholds for both periodic and non-periodic motion of the system. The master stability function is applied to predict the synchronization thresholds for longer chains of oscillators basing on two oscillator probe. It is shown that synchronization is possible both for three and four coupled oscillators under certain circumstances. Our results confirmed that this technique can be also applied for the systems with discontinuities. 相似文献
608.
In this paper, we present gold-plating polycarbonate (PC) microchannels. The fabrication of the gold microfluidic channels is achieved by tuning the sequence of reagent insertion into milled and closed submillimeter PC system channels. The resulting gold surface can be utilized in many applications where the benefits of microfluidics, (bio)chemistry of surfaces, and electrochemistry can be combined. Here, we combine the advantages of electrochemistry with microfluidics by mixing the gold sensor with microfluidics. This approach differs from the classic one – the sensor will undergo modifications (e. g., shape and size) depending on the specific scientific problem and will be designed individually; hence its characteristics will be changed. Our goal in this work is to indicate new possibilities for combining two methodologies – electrochemistry and microfluidics. In our work, we emphasize that it confirms the validity of our chosen concept (proof-of-concept). In this work, we present one such application, the use of a gold microfluidic channel as a working electrode (WE). We describe the microchip‘s construction and electrochemical characterization, including the gold flow-through WE, the Ag/AgCl wire pseudo-reference, and the Pt auxiliary electrode. The measured current is the result of the flow through a rectangular duct of the gold microchannel electrode embedded in the four walls of the chip. 相似文献
609.
Liu L Tan G McPherson G John VT Maskos K Bose A 《Langmuir : the ACS journal of surfaces and colloids》2008,24(17):9286-9294
The addition of phosphatidylcholine to AOT water-in-oil microemulsions leads to the formation of a rigid gel as the water content is increased above a specific threshold. This system is a gel-like crystalline phase where the microstructure evolves from reverse hexagonal to lamellar with increasing water content and/or temperature. Couette sheared (1)H and (31)P NMR experiments carried out at varying temperature and water content show distinct signatures with microstructure evolution. Because the system has been fully characterized through small-angle neutron scattering, it is possible to relate the NMR signatures to the microstructure. The NMR technique therefore complements scattering techniques but is additionally useful because the technique also picks up isotropic signatures from concurrently occurring noncrystalline phases. The use of NMR to identify such lyotropic gel-like crystalline phases allows easy correlation between templated materials synthesis in these phases and phase microstructure. NMR can therefore be used as a probe to understand microstructure in specific surfactant systems and to characterize the retention of microstructure during materials synthesis. 相似文献
610.
Andreas Kirschning Kirsten Harmrolfs Josef Messinger Karol Grela 《Tetrahedron letters》2008,49(18):3019-3022
The cross-metathesis of allylestrone with acrylic acid derivatives using homogeneous and heterogenized Ru-catalysts was evaluated for the synthesis of a new 17β-hydroxysteroid dehydrogenase type 1 inhibitor. Hoveyda-type catalyst containing an additional diethylamino group turned out to be comparably active as homogeneous Grubbs II catalyst after immobilization on an acidic ion exchange resin which greatly facilitated workup. 相似文献