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851.
B. Tomas Johansson 《International Journal of Mathematical Education in Science & Technology》2018,49(1):131-137
Evaluation of the cosine function is done via a simple Cordic-like algorithm, together with a package for handling arbitrary-precision arithmetic in the computer program Matlab. Approximations to the cosine function having hundreds of correct decimals are presented with a discussion around errors and implementation. 相似文献
852.
B. Tomas Johansson 《International Journal of Mathematical Education in Science & Technology》2019,50(4):617-628
A method based on oblique projection is presented for construction of sundials. The derived formulas are classical, but usage of vectors and projections renders a coherent presentation rather than a number of special cases. The presented work is aimed to be useful for those taking a beginning module on vector algebra. 相似文献
853.
Tomas Ya. Azizov Valerii A. Senderov Viktor A. Khatskevich 《Journal of Mathematical Sciences》2014,200(3):295-304
We consider the theory of operators in spaces with indefinite metric. Strict plus-operators acting between two Krein spaces are considered. A construction showing that, under certain conditions, a strict plus-operator can be considered as a bistrict plus-operator without loss of generality is given. 相似文献
854.
We prove that the relative commutator with respect to a subvariety of a variety of Ω-groups introduced by the first author can be described in terms of categorical Galois theory. This extends the known correspondence between the Fröhlich–Lue and the Janelidze–Kelly notions of central extension. As an example outside the context of Ω-groups we study the reflection of the category of loops to the category of groups where we obtain an interpretation of the associator as a relative commutator. 相似文献
855.
Jan D. Buriánek Jaroslav Kvicala Lada Sekerova Bernd H. Müller Robert Francke Tomas Bystron 《Electroanalysis》2023,35(5):e202200376
Diaryliodonium salts are used in organic chemistry, materials science and pharmaceutical chemistry. For the quantitative analysis of diaryliodonium salts, only instrumentally demanding techniques requiring highly skilled operators are available. Surprisingly, no titration method taking advantage of the oxidising ability of diaryliodonium is available in the literature. In the present work, a titration method for the determination of diaryliodonium salts is presented. It is based on the reaction of diaryliodonium species with ascorbic acid, whose excess is subsequently determined by means of iodometric potentiometric titration. Application of the protocol to various diaryliodonium salts revealed the scope and limitations of the method. 相似文献
856.
Tomas Drevinskas Aaron C. Noell Florian Kehl Konstantin Zamuruyev Mauro S. Ferreira Santos Maria F. Mora Travis D. Boone Trinh Hoac Richard C. Quinn Antonio J. Ricco Peter A. Willis 《Electrophoresis》2023,44(13-14):1047-1056
Capillary electrophoresis (CE) holds great promise as an in situ analytical technique for a variety of applications. However, typical instrumentation operates with open reservoirs (e.g., vials) to accommodate reagents and samples, which is problematic for automated instruments designed for space or underwater applications that may be operated in various orientations. Microgravity conditions add an additional challenge due to the unpredictable position of the headspace (air layer above the liquid) in any two-phase reservoir. One potential solution for these applications is to use a headspace-free, flow-through reservoir design that is sealed and connected to the necessary reagents and samples. Here, we demonstrate a flow-through high-voltage (HV) reservoir for CE that is compatible with automated in situ exploration needs, and which can be electrically isolated from its source fluidics (in order to prevent unwanted leakage current). We also demonstrate how the overall system can be rationally designed based on the operational parameters for CE to prevent electrolysis products generated at the electrode from entering the capillary and interfering with the CE separation. A reservoir was demonstrated with a 19 mm long, 1.8 mm inner diameter channel connecting the separation capillary and the HV electrode. Tests of these reservoirs integrated into a CE system show reproducible CE system operation with a variety of background electrolytes at voltages up to 25 kV. Rotation of the reservoirs, and the system, showed that their performance was independent of the direction of the gravity vector. 相似文献
857.
Subeesh Madayanad Suresh Le Zhang David Hall Changfeng Si Gaetano Ricci Tomas Matulaitis Alexandra M. Z. Slawin Stuart Warriner Yoann Olivier Ifor D. W. Samuel Eli Zysman-Colman 《Angewandte Chemie (International ed. in English)》2023,62(8):e202215522
We present a p- and n-doped nonacene compound, NOBNacene, that represents a rare example of a linearly extended ladder-type multiresonant thermally activated delayed fluorescence (MR-TADF) emitter. This compound shows efficient narrow deep blue emission, with a λPL of 410 nm, full width at half maximum, FWHM, of 38 nm, photoluminescence quantum yield, ΦPL of 71 %, and a delayed lifetime, τd of 1.18 ms in 1.5 wt % TSPO1 thin film. The organic light-emitting diode (OLED) using this compound as the emitter shows a comparable electroluminescence spectrum peaked at 409 nm (FWHM=37 nm) and a maximum external quantum efficiency (EQEmax) of 8.5 % at Commission Internationale de l’Éclairage (CIE) coordinates of (0.173, 0.055). The EQEmax values were increased to 11.2 % at 3 wt % doping of the emitter within the emissive layer of the device. At this concentration, the electroluminescence spectrum broadened slightly, leading to CIE coordinates of (0.176, 0.068). 相似文献
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