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1.
Abstract— The quantum yield of the photodynamic inactivation of lysozyme increases in the sequence acridine orange, methylene blue, proflavine and acriflavine (1:5:6:12). At least up to protein concentrations of 0.1 m M , singlet oxygen is exclusively responsible for the inactivation of the enzyme. For methylene blue, acriflavine and proflavine the quantum yields decrease considerably with increasing dye concentrations. From measurements in H2O and D2O buffer solutions it was concluded that in the case of methylene blue the effect is mainly caused by the quenching of singlet oxygen [rate constant (3–4) × 108 M −1 s−1]. For the acridine sensitizers both singlet oxygen and dye triplet quenching processes have to be taken into consideration. It has been found that all sensitizers act as competitive inhibitors of the enzymatic reaction of lysozyme. However, the dye-protein interaction near the active center cannot be responsible for the observed dye self-quenching effect.  相似文献   
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The novel ionic ozonide {[N(C4H9)4](O3)}4·4.75NH3 was synthesized by ion‐exchange reaction in liquid ammonia. The crystal structure was determined by single crystal diffraction at 100 K (monoclinic space group P21, a = 15.014(11) Å, b = 13.696(10) Å, c = 19.890(15) Å, β = 105.407(12)°, V = 3943(5) Å3, Z = 2). The structure consists of a packing of sandwich‐like dimeric ion pairs in which two ozonide anions are interspersed between two tetrabutylammonium cations. Ammonia molecules from the solvent are localized in cavities in the structure. They are involved in hydrogen bonding with the ozonide ions. The desolvated tetrabutylammonium ozonide forms stable solutions in dichloromethane which may open up novel possibilities of tapping into the synthetic potential of the ozonide ion.  相似文献   
3.
The elastic and inelastic backscattering from Si(111) surfaces and evaporated amorphous silicon were measured as a function of the primary energyE p (30eVE p 200eV). A detailed evaluation of the amplitude of the volume plasmon lossA vp was carried out in the loss spectra. In contrast to single crystals amorphous silicon produces a smooth curve as function of the energy, both for the elastic backscattered electron current and forA vp (E).To interpret the measured curves for the amorphous Si calculations were made for the elastic scattering and for the excitation probability of the volume plasmon in a randium-jellium-model. In the case of elastic scattering a random distribution of atoms is assumed. In the case of inelastic scattering the free electron model is used. Double scattering processes are included. The comparison between theory and experiment shows satisfactory agreement for elastic scattering. The energy dependent excitation probability of the volume plasmon is excellently represented by this model.  相似文献   
4.
This review paper covers the low temperature wet growth of nano-engineered particles of ZnO-based mixed metal oxides, their growth mechanism, and characterization using X-ray diffraction, SEM, TEM and IR, UV–visible, and XPS spectral techniques. Main focus of this article is centered on low temperature semi-wet methods of synthesis that are suitable for large scale production of zinc oxide-based systems mixed with iron oxide, copper oxide, nickel oxide and cobalt oxide. These mixed metal oxides have broad industrial applications as catalyst, semiconductors, adsorbents, superconductors, electro-ceramics, and antifungal agents in addition to extensive applications in medicines. This paper discusses the low-cost and environment friendly synthesis of these mixed metal oxides, measurement of properties and applicability of these materials systems.  相似文献   
5.
Depending on the solvothermal reaction conditions, we obtained three different metal-organic frameworks with yttrium(III) as metal component and 2,5-dihdyroxyterepthalic acid (H4dhtp) as bifunctional organic linker: Y2(H2dhtp)3(dmf)4 · (dmf)2 (CPO-29) contains dinuclear, paddle-wheel like inorganic secondary building units (SBUs) connected by the organic linker to a network with α-Po topology, while Y2(H2dhtp)(dhtp)(dmf)2 (CPO-30) and Y2(H2dhtp)(dhtp)(dmf)2(H2O)2 · (H2O)4 (CPO-31) contain one-dimensional inorganic SBUs that differ in how the half- and fully deprotonated ligands are connected to and arranged around them. Only the carboxylic acid groups of the organic linker are deprotonated in CPO-29, while CPO-30 and CPO-31 contain both 2,5-dihydroxyterephthalate (H2dhtp2–) linkers and fully deprotonated 2,5-dioxidoterephthalate (dhtp4–) linkers. All three compounds contain large volumes filled with solvent, but we were able to demonstrate permanence of porosity only for CPO-30. Variable temperature powder X-ray diffraction reveals that CPO-29 and CPO-31 undergo discontinuous phase transitions upon heating, and the flexibility of the framework structure indicated by these might be the reason for the inability to access the pore volume. Desolvated CPO-30 and CPO-31 are polymorphs, whose network structures differ in whether the H2dhtp2– and dhtp4– linkers are located in cis or trans arrangement around the inorganic SBU.  相似文献   
6.
Thermal contact resistance between two solids is discussed with regard to its influence on the measurements of temperature and thermo-physical parameters in micro- and nano-structures. Two important applications are considered: thin film coatings on substrates and local measurements with a nano-probe in scanning thermal microscopy. The mechanical contact of a copper layer on carbon is measured by adhesion strength experiments and correlated to the thermal transport across the interface deduced from infrared radiometric measurements. A novel quantity the thermal wave contrast is introduced which takes into account the interface resistance and modifications of the coating and substrates at the interface. With regard to scanning thermal microscopy the contact resistance problem is discussed for 3ω-measurements in the active mode and for temperature measurements in the passive mode. It is shown that the thermo-elastic response can offer a means to avoid the influence of the thermal contact resistance on local temperature measurements.  相似文献   
7.
The effective thermal depth profiles of copper-carbon interface systems with and without additional metallic submicron bond layers have been measured by means of modulated IR radiometry and have been evaluated using a new quantity, the thermal (wave) contrast, defined with the help of the calibrated thermal wave amplitudes. Useful correlations between the thermal wave contrast and the mechanical adhesion strength between copper film and carbon substrate have been found. By comparing the measurements based on thermal wave excitation and contact-less IR detection with microscopic contact temperature measurements close to the copper-carbon interface, the similarities between the two experiments are discussed, and the advantages and problems related to the thermal wave contrast are analyzed.  相似文献   
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