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121.
We introduce dual-pump coherent anti-Stokes-Raman scattering (dual-CARS) microscopy. This new technique permits simultaneous imaging of two species characterized by different molecular vibrations, as well as the removal of nonresonant background. This is achieved by using three synchronized laser pulses probing two different vibrations. We demonstrate the virtues of the method by imaging a mixture of nondeuterated and deuterated lipids, clearly distinguishing the individual components and their organization in the mixed arrangement. Further, dual-CARS images of lipid stores in living Caenorhabditis elegans nematodes show that the suppression of the nonresonant background results in significantly enhanced image contrast. 相似文献
122.
For Archimedean vector lattices X, Y and the positive cone
\mathbbL{\mathbb{L}} of all regular linear operators L : X → Y, a theory of sequential convergences of functions connected with an
\mathbbL{\mathbb{L}} -valued measure is introduced and investigated. 相似文献
123.
Stepanka Kuckova Kristyna Zitkova Ondrej Novotny Tatiana Smirnova 《Journal of separation science》2019,42(22):3487-3496
Cheeses are a group of fermented dairy products that are produced all over the world in various forms and flavours. Milk, especially sheep or goat milk, is still regarded as an expensive raw material in the world, which makes milk and milk products highly attractive as a fraud target. Most often, such fraud includes partial or complete substitution with cheaper sorts of milk (e.g. bovine milk). The aim of this work was to verify the authenticity of 27 cheeses commonly emerging on the Czech food market. The cheeses were distinguished on the basis of milk animal species origin. For this purpose, two mass spectrometry techniques were used: matrix‐assisted laser desorption/ionization with time of flight mass spectrometry together with principal component analysis method and liquid chromatography coupled with electrospray ionization and quadrupole time‐of‐flight mass spectrometry. The results were a partial success, because the cheeses could only be partially distinguished with the first mass spectrometry technique probably because of the influence of some protein additive materials in cheeses. The second technique allowed for collecting higher quality results and thus appears to be highly suitable for the research task. 相似文献
124.
W. Kundrat 《Analytical and bioanalytical chemistry》1968,243(1):624-630
A rapid qualitative diffusiontest using Bac. stearothermophilus as test organism for the detection of antibiotics, sulphanilamides and other chemotherapeutic agents is described. The test requires 50 min at a temperature of 65° C. The method is not applicable to the evaluation of detergents, disinfectants and preservatives as used in food industry. 相似文献
125.
Semilinear second order stochastic hyperbolic equations driven by a spatially
homogeneous Wiener process are studied. Sufficient conditions in terms of
Lyapunov functions for the equation to have global mild or strong solutions are
found. In particular, the results apply to equations with polynomial drift and
diffusion coefficients. 相似文献
126.
Ondrej Zindulka 《Proceedings of the American Mathematical Society》2000,128(6):1769-1778
The following problem is discussed: If is a topological space of universal measure zero, does it have also dimension zero? It is shown that in a model of set theory it is so for separable metric spaces and that under the Martin's Axiom there are separable metric spaces of positive dimension yet of universal measure zero. It is also shown that for each finite measure in a metric space there is a zero-dimensional subspace that has full measure. Similar questions concerning perfectly meager sets and other types of small sets are also discussed.
127.
M. M. Kundrat 《International Applied Mechanics》2000,36(9):1235-1241
The problem on separation of a rigid linear inclusion in an orthotropic matrix is analytically solved by using Cherepanov's -concept in the theory of cracks. It is assumed that plastic or prefracture zones, which are modeled by discontinuities of tangential displacements along the matrix–inclusion interface, develop near the inclusion apices under loading. The problem is reduced to the Cauchy problem for a differential equation of the first order. The effective length of the inclusion is found for specific values of its initial length and external loads 相似文献
128.
Controllable Growth of Perovskite Films by Room‐Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells 下载免费PDF全文
Bin Yang Ondrej Dyck Jonathan Poplawsky Jong Keum Sanjib Das Alexander Puretzky Tolga Aytug Pooran C. Joshi Christopher M. Rouleau Gerd Duscher David B. Geohegan Kai Xiao 《Angewandte Chemie (International ed. in English)》2015,54(49):14862-14865
A two‐step solution processing approach has been established to grow void‐free perovskite films for low‐cost high‐performance planar heterojunction photovoltaic devices. A high‐temperature thermal annealing treatment was applied to drive the diffusion of CH3NH3I precursor molecules into a compact PbI2 layer to form perovskite films. However, thermal annealing for extended periods led to degraded device performance owing to the defects generated by decomposition of perovskite into PbI2. A controllable layer‐by‐layer spin‐coating method was used to grow “bilayer” CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple air exposure at room temperature for making well‐oriented, highly crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ca. 800 nm and a high device efficiency of 15.6 %, which is comparable to values reported for thermally annealed perovskite films. 相似文献
129.
Highly polluted forest/tilled soils and stream sediments from a mining and smelting area were subjected to single-extraction procedures to determine the extractable contents of Cd, Cu, Pb, and Zn. The results obtained from four widely used operationally defined single extraction tests were compared: deionised water, 0.01 mol L−1 CaCl2, 1 mol L−1 NH4NO3 and 0.005 mol L−1 DTPA. The analytical data were coupled with measurement of the pH and Eh in extracts, mineralogical investigations and thermodynamic modelling using the PHREEQC-2 code. The changes in the pH of the equilibrated suspensions significantly influenced the metal extractabilities, with higher values in the lower pH regions. Although the DTPA procedure generally extracted the highest amounts of metals, it was found to be unsuitable for highly organic acidic forest soils, where anionic metal-DTPA complexes are assumed to be re-adsorbed on the positively charged surfaces of soil organic matter and oxides. The NH4NO3 extraction was also unsuitable due to the high ionic strength (1 mol L−1), limiting the use of the thermodynamic speciation model and the formation of the Cu(NH3)2+ complex, leading to acidification of the suspension. 0.01 mol L−1 CaCl2 can be proposed as the most appropriate extraction medium, suitable for speciation modelling and analytical determinations using ICP-techniques and having an ionic strength similar to that of the soil solution. The metals are present in free ionic forms or chlorocomplexes in the CaCl2 extracts, preventing their re-adsorption on the positively charged surfaces of soil solids (organic matter, Fe- and Mn-oxides) in acidic and circum-neutral conditions. 相似文献
130.
Novel seven-membered nucleoside phostones were prepared by the reaction of chlorodiethyl phosphite with 3',5'-acetals or ketals derived from xylo-dT. A mechanism for the ring enlargement was proposed, and support for it was provided by ab initio calculations. 相似文献