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Abstract— Rapid inhibition of hypocotyl extension of de-etiolated Cucumis sativus L. by blue light is described, and compared with responses to white fluorescent light. Rapid inhibition of hypocotyl growth by blue light via the specific blue light photoreceptor requires a minimum Buence rate. Above this minimum value rapid modulations of growth rate accompany changes in blue light fluence rate. An initial response to blue light, or to a step-up in blue fluence rate takes less than 5 min. A drop from high to low fluence rate blue light (or to darkness) is followed by a recovery of the growth rate after about 20 min. A change from a low fluence rate to darkness elicits a more rapid recovery of growth rate (within 7 min). Similar responses were obtained in seedlings de-etiolated for a few hours and for several days. 相似文献
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A computer-controlled spectroradiometer system is described that comprises a commercial spectroradiometer, a low-cost microcomputer and a purpose-built interface. The system is used in establishing controlled light environments for the study of plant growth. The method used to link the computer and spectroradiometer is described and an outline of the required control software is given. A set of application programs has been developed to convert the raw spectral data into meaningful physiological/photomorphogenic quantities. This obviates the large volume of manual measurements and calculations that were previously necessary. 相似文献
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Chaudhary Ankita Khanna Garima Chopra Haritma Gaba Ritu 《Research on Chemical Intermediates》2022,48(5):2267-2278
A simple, efficient, and eco-friendly protocol for the synthesis of 1,3-oxazine derivatives, viz. 7-aryl-7,8-dihydro-6H-[1,3]dioxolo[4′,5′:4,5]benzo[1,2-e][1,3]oxazines and 3-aryl-3,4-dihydro-2H- naphtho[2,3-e][1,3]oxazine-5,10-diones, involving one-pot multicomponent condensation reaction of various amines and formaldehyde with sesamol/2-hydroxy-1,4-naphthoquinone, respectively, catalyzed by a choline chloride–oxalic acid deep eutectic solvent has been developed. The method offers several advantages, including mild reaction conditions, simple operating procedure, recyclable and biodegradable catalyst, short reaction times, and excellent yields of the target products.
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Hishikar Prafull Dhiman S. K. Tiwari Anil Kumar Gaba Vivek Kumar 《Journal of Thermal Analysis and Calorimetry》2022,147(10):5549-5574
Journal of Thermal Analysis and Calorimetry - The present study reviews the physical attributes of the fluid behaviour in the flow regimes of steady cross-flow around two infinite circular... 相似文献
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Tripuranthakam S. Babu Marcel A. K. Jansen† Bruce M. Greenberg Victor Gaba Shmuel Malkin Autar K. Mattoo Marvin Edelman 《Photochemistry and photobiology》1999,69(5):553-559
Abstract— Plants exposed to a mixture of photosynthetically active radiation (PAR) and UVB radiation exhibit a marked boost in degradation of the D1 and D2 photosysteni II (PS II) reaction center proteins beyond that predicted by the sum of rates in PAR and UVB alone (amplified degradation). Becausee degradation driven by visible or UVB radiation alone is uncoupled from PS II redox status, it was therefore assumed that the mixed-light-amplified component of degradation would behave similarly. Surprisingly, amplified degradation proved to be coupled tightly to the redox status of PS II. We show that inactivation of the PS II water oxidation by heat shock or oxidation of the plastosemiquinone (QA -) by silicomolybdate nullifies only the amplified component of degradation but not the basic rates of degradation under PAR or UVB alone. The data are interpreted to indicate that formation of plastosemiquinone or an active water-oxidizing Mn4 cluster, is the UVB chromophore involved in amplified degradation of the D1 and D2 proteins. Furthermore, accumulation of QA -by 3-(3,4-dichlorophenyl)-1,1-dimethylurea or 2-bromo-3-methyl-6-isopropyl-4-nitrophenol stimulated the mixed-light-amplified degradation component. Thus, amplified degradation of the D1 and D2 proteins in mixed radiance of PAR plus UVB (which simulates naturally occurring radiance) proceeds by a mechanism clearly distinct from that involved in degradation under PAR or UVB alone. 相似文献
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D. Yu. Sugak A. O. Matkovskii I. M. Solskii B. M. Kopko V. Ya. Oliinyk I. V. Stefanskii V. M. Gaba V. V. Grabovskii I. M. Zaritskii L. G. Rakitina 《Crystal Research and Technology》1997,32(6):805-811
The technological procedure of the manufacturing of the LiNbO3˙ single crystals doped with 5 mol.% MgO is described in this paper. The results of the investigation of the crystal optical properties, ESR spectra and optical homogeneity are presented. The refractive index dispersion in 300–700 nm region and their temperature dependencies in 20–500 °C range are measured. The dispersion curve is approximated by the two oscillator Sellmeier formula. The data on the LiNbO3: MgO crystal optical resistance are presented. 相似文献
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We investigate the effect of magic angle spinning on heteronuclear spin decoupling in solids. We use an analytical Floquet-van Vleck formalism to derive expressions for the powder-averaged signal as a function of time. These expressions show that the spectrum consists of a centerband at the isotropic frequency of the observed spin, omega(0), and rotational decoupling sidebands at omega(0)+/-omega(1)+/-momega(r), where omega(1) is the decoupling field strength and omega(r) is the rotation frequency. Rotary resonance occurs when the rotational decoupling sidebands overlap with the centerband. Away from the rotary resonance conditions, the intensity of the centerband as a function of omega(r)/omega(1) is simply related to the total intensity of the rotational decoupling sidebands. Notably, in the absence of offset terms it is shown that as omega(1) decreases, the centerband intensity can decrease without any associated broadening. Furthermore, the centerband width is shown to be independent of spinning speed, to second order for the effects we consider. The effects of I spin chemical shift anisotropy and homonuclear dipolar couplings are also investigated. The analytical results are compared to simulations and experiments. 相似文献