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151.
152.
Statistically Optimal Nearfield Acoustical Holography (SONAH) can be used to reconstruct three-dimensional sound fields by projecting two-dimensional data measured on a “small” aperture that partially covers a composite sound source in a “static” fluid medium. Here, an improved SONAH procedure is proposed that includes the mean flow effects of a moving fluid medium while the sound source and receivers are stationary. The backward projection performance of the proposed procedure is further improved by using a wavenumber filter to suppress subsonic noise components. Through numerical simulations at Mach 0.6, it is shown that the improved procedure can accurately reconstruct sound source locations and radiation patterns: e.g., the spatially averaged reconstruction errors of the conventional and improved SONAH procedures are 15.40 dB and 0.19 dB, respectively, for a monopole simulation and 21.60 dB and 0.19 dB for an infinite-size panel. The wavenumber filter further reduces spatial noise, e.g., decreasing the reconstruction error from 1.73 dB to 0.19 dB for the panel simulation. An existing data measured in a wind tunnel operating at Mach 0.12 is reused for the validation. The locations and radiation patterns of the two loudspeakers are successfully identified from the sound fields reconstructed by using the proposed SONAH procedure.  相似文献   
153.
We present an economical setup for faithful entanglement sharing against collective noise. It is composed of polarizing beam splitters, half wave plates, polarization independent wavelength division multiplexers, and frequency shifters. An arbitrary qubit error on the polarization state of each photon in a multi-photon system caused by the noisy channel can be rejected, without resorting to additional qubits, fast polarization modulators, and nondestructive quantum nondemolition detectors. Its success probability is in principle 100%, which is independent of the noise parameters, and it can be applied directly in any one-way quantum communication protocol based on entanglement.  相似文献   
154.
We have developed a metal-free radical cascade reaction of N-substituted 2-aryl indoles with readily available sulfonyl hydrazides for the rapid construction of arylsulfonyl-substituted indolo[2,1-a]isoquinolin-6(5H)-one derivatives. With the TBAI–TBHP catalytic system, a broad series of structurally diverse indolo[2,1-a]isoquinolin-6(5H)-one derivatives were obtained in moderate to excellent yields. The reaction features mild reaction conditions, operationally easiness, scaled-up feasibility, and high functional-group-tolerance.  相似文献   
155.
In this work, an electrochemical dihydronicotinamide adenine dinucleotide (NADH) sensor based on the catalytic growth of Au nanoparticles (Au NPs) on glassy carbon electrode was developed. Catalyzed by Au NPs immobilized on pretreated glassy carbon electrode, the reduction of AuCl4 ? in the presence of hydroquinone and cetyltrimethyl ammonium chloride led to the formation of enlarged Au NPs on the electrode surface. Spectrophotometry and high-resolution scanning electronic microscope (SEM) analysis of the sensor morphologies before and after biocatalytic reaction revealed a diameter growth of the nanoparticles. The catalytic growth of Au NPs on electrode surface remarkably facilitated the electron transfer and improved the performance of the sensor. Under optimal conditions, NADH could be detected in the range from 1.25?×?10?6 to 3.08?×?10?4 M, and the detection limit was 2.5?×?10?7 M. The advantages of the proposed sensor, such as high precision and sensitivity, fast response, low cost, and good storage stability, made it suitable for on-line detection of NADH in complex biological systems and contaminant degradation processes.
Figure
Schematic presentation of the bioelectrocatalytic sensing of NADH  相似文献   
156.
The migration of ions is known to be associated with various detrimental phenomena, including current density-voltage hysteresis, phase segregation, etc., which significantly limit the stability and performance of perovskite solar cells, impeding their progress toward commercial applications. To address these challenges, we propose incorporating a polymerizable organic small molecule monomer, N-carbamoyl-2-propan-2-ylpent-4-enamide (Apronal), into the perovskite film to form a crosslinked polymer (P-Apronal) through thermal crosslinking. The carbonyl and amino groups in Apronal effectively interact with shallow defects, such as uncoordinated Pb2+ and iodide vacancies, leading to the formation of high-quality films with enhanced crystallinity and reduced lattice strain. Furthermore, the introduction of P-Apronal improves energy level alignment, and facilitates charge carrier extraction and transport, resulting in a champion efficiency of 25.09 %. Importantly, P-Apronal can effectively suppress the migration of I ions and improve the long-term stability of the devices. The present strategy sets forth a path to attain long-term stability and enhanced efficiency in perovskite solar cells.  相似文献   
157.
We here report glycosyl sulfoxides appended with an aryl iodide moiety as readily available, air and moisture stable precursors to glycosyl radicals. These glycosyl sulfoxides could be converted to glycosyl radicals by way of a rapid and efficient intramolecular radical substitution event. The use of this type of precursors enabled the synthesis of various complex C‐linked glycoconjugates under mild conditions. This reaction could be performed in aqueous media and is amenable to the synthesis of glycopeptidomimetics and carbohydrate‐DNA conjugates.  相似文献   
158.
Organotincompoundsareextensivelystudiedfortheirbiologicalactivity'.Organogermaniumisanotherkindofelementthathasawiderangeofbiologicalactivity=.Tolinkbiologicalactivepropertiesoforganotinandorganogermaniumcompounds.wehavepreviouslyreportedthebiologicalactivityoftrialkyltingermylpropionates'andanticanceractivityofdibutyltindigermylpropionates'.ItiswellknownthatTorque(his[tri(2-methyl-2-phenylpropyl)tin]oxide)iswidelyusedinagricultureasanacaricide.Inthispaper,asthecontinuationofourpreviouswork"'…  相似文献   
159.
High surface area porous poly(phenylene butadiynylene) networks were obtained (BET surface area up to 842 m(2) g(-1)) by the palladium-catalyzed homocoupling of 1,3,5-triethynylbenzene and 1,4-diethynylbenzene.  相似文献   
160.
A highly efficient cobalt(II)‐catalyzed alkynylation/annulation of terminal alkynes assisted by an N,O‐bidentate directing group is described. This protocol is characterized by wide substrate scope utilizing cheap cobalt catalysts, and offers a new approach to 3‐methyleneisoindolin‐1‐one, which can be converted into an oxadiazine salt in one step. Moreover, the directing group could be removed in three steps.  相似文献   
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