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991.
Daura Vega Zoraida Sosa 《International journal of environmental analytical chemistry》2013,93(3):185-197
Abstract A sequential injection analysis method for the simultaneous spectrophotometric determination of phosphate and silicate has been developed. The method is based on the different reaction rates of the heteropolymolybdate formation reactions. Concentrations within the range 0.026—0.485 mmol P l?1 and 0.125—2.848 mmol Si l?1 have been determined at a frequency of 30 samples per hour. An R.S.D. of 2.1% was obtained for 0.162 mmol P l?1 and of 1.1% for 1.424 mmol Si l?1. The method was found to be suitable for the determination of phosphate and silicate in wastewater. 相似文献
992.
Polymer dispersed liquid crystal (PDLC) films with the size gradient of the LC droplets were prepared based on the epoxy/acrylate hybrid polymer matrix. The ultraviolet (UV) intensity gradient was induced by the UV-absorbing dye over the thickness of the samples. Taking advantage of the difference between the epoxy monomers and acrylate monomers in polymerisation rates and the UV intensity gradient, the gradient distribution of the LC droplet size was formed in PDLC films. The effect of the size gradient of the LC droplets on the electro-optical and the light-scattering properties of PDLC films was investigated. The results showed that due to the size gradient distribution of the LC droplets, PDLC films could exhibit the strong light scattering in the UV-visible-near infrared (VIS-NIR) region. Consequently, it provides a potential approach for modulating NIR light transmittance. 相似文献
993.
Li Zhu Kun Liu Shudong Zheng Dr. Xiacong Zhang Prof. Dr. Jiatao Yan Prof. Dr. Wen Li Prof. Dr. Afang Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(40):10470-10476
Water-soluble and thermoresponsive macrocycles with stable inclusion toward guests are highly valuable to construct stimuli-responsive supramolecular materials for versatile applications. Here, we develop such macrocycles – ureido-substituted cyclodextrins (CDs) which exhibit unprecedented upper critical solution temperature (UCST) behavior in aqueous media. These novel CD derivatives showed good solubility in water at elevated temperature, but collapsed from water to form large coacervates upon cooling to low temperature. Their cloud points are greatly dependent on concentration and can be mediated through oxidation and chelation with silver ions. Significantly, the amphiphilicity of these CD derivatives is supportive to host-guest binding, which affords them inclusion abilities to guest dyes. The inclusion complexation remained nearly intact during thermally induced phase transitions, which is in contrast to the switchable inclusion behavior of lower critical solution temperature (LCST)-type CDs. Moreover, ureido-substituted CDs were exploited to co-encapsulate a pair of guest dyes whose fluorescence resonance energy transfer process can be switched by the UCST phase transition. We therefore believe these novel thermoresponsive CDs may form a new strategy for developing smart macrocycles and allow for exploring smart supramolecular materials. 相似文献
994.
《随机分析与应用》2013,31(2):251-274
Abstract The purpose of this paper is to investigate pathwise stability for certain Hilbert space-valued stochastic evolution equations. We are especially interested in the robustness analysis of perturbed stochastic differential equations in infinite dimensions. Sufficient conditions are established to ensure the almost surely stable decay of the given stochastic systems. Lastly, a corollary and corresponding example are studied to illustrate our theory. 相似文献
995.
996.
Comment on “On the Neumann function and the method of images in spherical and ellipsoidal geometry”
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In this note, we point out two errors in the article “On the Neumann function and the method of images in spherical and ellipsoidal geometry” by Dassios and Sten. Two corrections are then proposed. 相似文献
997.
Controlled discrete–time stochastic processes axe studied using the convex–analytic approach. Some new properties of strategic measures spaces are established, particular Markov models are considered. The meaningful example is presented. 相似文献
998.
The propagation of rough and smooth wall pre-existing turbulent fluid fractures is investigated. The laminar fluid fracture is included as a special case for comparison. Lubrication theory is assumed to apply in the fracture and turbulence is introduced through the wall shear stress. The Perkins–Kern–Nordgren approximation is made in which the fluid pressure is proportional to the half-width of the fracture. The fracture half-width satisfies a non-linear diffusion equation. By using a linear combination of the Lie point symmetries of the non-linear diffusion equation a group invariant solution for the fracture length, volume and half-width is derived. The evolution of the length, half-width and mean flow velocity is analysed for a range of working conditions at the fracture entry. It is found that the mean flow velocity increases approximately linearly along the fracture. 相似文献
999.
Ming-Zhao Wang Ying Li Jin-Jin Ji Gai-Ling Huang Xin Zhang Si-Hui Li Xiao-Jing Yang 《中国化学快报》2013,24(7):593-596
Four Cu2+ complexes of salicylidene-amino acid Schiff base with 1,10-phenanthroline(Phen) or 2,2’- bipyridine(Bipy) were successfully intercalated in interlayer galleries of Mg/Al-NO3-layered double hydroxide(LDH) by the swelling-restored method.The hybrids were characterized by elemental analysis,X-ray diffraction,FT-IR spectra,UV-vis DRS,TG-DTA and SEM observation.Good protection of the complexes by LDH in neutral and weak acidic solutions was revealed by UV spectra,cyclic voltammograms and luminescence spectra. 相似文献
1000.
Crosslinked polyacrylamides were synthesized by solution polymerization using benzoyl peroxide as the radical initiator. The water–insoluble polymer obtained was functionalized by reacting with hydroxylamine to convert the amide group into hydroxamic acid group. The resultant functionalized polymer was characterized in terms of moisture uptake, elemental composition, IR spectra, thermal stability, exchange capacity and heavy metal sorption. The sorbent, obtained in particulate form, was investigated for its sorption properties with respect to uranium from uranyl nitrate solutions under unstirred batch conditions. This paper will concentrate on preparation, characterization and performance evaluation with respect to uranium sorption as a function of concentration, time, solution pH and temperature. The potential of this sorbent for uranium and other heavy metal ion recovery from sea water is ascertained. 相似文献