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91.
Ch. Jesús F. Socorro M. Rodríguez de Rivera 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1003-1007
A calorimetric sensor has been developed for local and direct measurement of calorific dissipations in different parts of the human body. The constructed prototype has a detection surface of 36 cm2. The calibration of the sensor is based on a semi-empirical model that permits to simulate the operation of the device, making easier an operational functioning method. The device is modeled as a system with two inputs and two outputs. The inputs are the calorific power (W) that is intended to be measured and the power (W pid) that dissipates a resistance, keeping constant the thermostat temperature through the use of a PID controller. The outputs are the thermostat temperature (T pid) and the calorimetric signal (y) that provides the thermopile that is in contact with the body. 相似文献
92.
The Thorpe-Ziegler reaction has been used in the preparation of enaminonitriles and cyclic ketones for many years. A wide variety of bases1 have been employed to acomplish this reaction, the most effective being the alkali metal salts of aralkyl amines. The reaction conditions vary from room temperature to toluene reflux temperature for long periods of time1. 相似文献
93.
A convenient synthesis of the cyclohexyl, (1R,3R,4S)-3-P-menthyl and (15-endo)-2-bomyl glyoxylates, from the respective alcohols and other very available materials, as a model applicable to that of other chiral, sensitive giyoxylates, is described. 相似文献
94.
Photoactive materials based on dye molecules incorporated into thin films or bulk solids are useful for applications as photosensitization, photocatalysis, solar cell sensitization and fluorescent labeling, among others. In most cases, high concentrations of dyes are desirable to maximize light absorption. Under these circumstances, the proximity of dye molecules leads to the formation of aggregates and statistical traps, which dissipate the excitation energy and lower the population of excited states. The search for enhancement of light collection, avoiding energy wasting requires accounting the photophysical parameters quantitatively, including the determination of quantum yields, complicated by the presence of light scattering when particulate materials are considered. In this work we summarize recent advances on the photophysics of dyes in light‐scattering materials, with particular focus on the effect of dye concentration. We show how experimental reflectance, fluorescence and laser‐induced optoacoustic spectroscopy data can be used together with theoretical models for the quantitative evaluation of inner filter effects, fluorescence and triplet formation quantum yields and energy transfer efficiencies. 相似文献
95.
Successive action of α-bromoesters and organometallics on hydroximates constitute a good way to obtain - 5,6 dihydro-1,4,2 dioxazines. 相似文献
96.
Álvaro Sánchez Rodríguez Zoraida Sosa Ferrera 《International journal of environmental analytical chemistry》2013,93(12):1166-1177
A solid phase extraction (SPE) technique for seawater samples coupled to quantification using liquid chromatography tandem-mass spectrometry (LC-MS/MS) is described to quantify relevant antifouling booster biocides of ecotoxicological concern (Diuron, TCMTB, Irgarol 1051 and Dichlofluanid). The optimised methodology provides a sensitive, easy to use and efficient analytical procedure with detection limits in the range of between 0.1 and 0.2?ng?L?1 and appropriate reproducibility (with analytical standard deviations of less than 10%). Spiked recoveries for all compounds exceeded 72%. The method was tested through a thorough monitoring regime of commercial port and marinas on the island of Gran Canaria (off the north-west coast of Africa) over a period of several months in 2008. Results provide the first data for antifouling booster biocides in the Canary Islands. Concentrations of Diuron and Irgarol 1051 in samples ranged between 2 and 195?ng?L?1 and 2 and 146?ng?L?1, respectively. TCMTB and Dichlofluanid were not detected. 相似文献
97.
Y. Arroyo Gómez J. A. López Sastre J. F. Rodríguez Amo M. A. Sanz Tejedor 《Journal of carbohydrate chemistry》2013,32(7):1051-1058
Abstract The asymmetric oxidation reaction of D-glyceraldehyde diethyl dithioacetal 1 and its di-O-acetyl derivative with a Sharpless reagent to produce the corresponding D-glyceraldehyde diethyl dithioacetal S-oxide derivatives takes place with high stereoselectivity. The configuration of the two new chiral centres formed is deduced. 相似文献
98.
Determination of estrogens in environmental water samples using 1,3‐dipentylimidazolium hexafluorophosphate ionic liquid as extraction solvent in dispersive liquid–liquid microextraction 下载免费PDF全文
Bárbara Socas‐Rodríguez Javier Hernández‐Borges María Asensio‐Ramos Antonio V. Herrera‐Herrera Jose A. Palenzuela Miguel Ángel Rodríguez‐Delgado 《Electrophoresis》2014,35(17):2479-2487
In this work, the potential of a symmetric dialkyl‐substituted ionic liquid (IL), 1,3‐dipenthylimidazolium hexafluorophosphate ([PPIm][PF6]), as extraction solvent in dispersive liquid–liquid microextraction (DLLME) has been studied for the analysis of a group of three natural (estriol, 17β‐estradiol, and 17α‐estradiol) and four synthetic (17α‐ethynylestradiol, diethylstibestrol, dienestrol, and hexestrol) estrogenic compounds as well as one mycotoxin with estrogenic activity (zearalenone) in different types of water samples (Milli‐Q, mineral, and wastewater). Separation, determination, and quantification were developed by HPLC‐DAD and a fluorescence detector (FD) connected in series. Factors influencing the IL‐DLLME procedure (sample pH, amount of IL, type and volume of disperser solvent, ionic strength, and assistance of vortex agitation) were investigated and optimized by means of a step‐by‐step approach. Once the optimum extraction conditions were established (10 mL of water at pH 8, 60 mg of [PPIm][PF6], 500 μL of ACN as disperser solvent and vortex agitation for 1 min), the calibration curves of the whole method (IL‐DLLME‐HPLC‐DAD/FD) were obtained and precision and accuracy were evaluated. It was demonstrated that the developed methodology was repeatable, accurate, and selective with limits of detection in the 0.30–0.57 μg/L and 13.8–37.1 μg/L range for FD and DAD, respectively. Relative recovery values were higher than 85% for the different types of water samples and the Student's t test demonstrated that there were not significant differences between the added and the found concentration. 相似文献
99.
Sánchez-Calderón Ismael Merillas Beatriz Bernardo Victoria Rodríguez-Pérez Miguel Ángel 《Journal of Thermal Analysis and Calorimetry》2022,147(22):12523-12533
Journal of Thermal Analysis and Calorimetry - Nowadays, developing advanced, highly insulating materials for minimizing heat losses in buildings is of utmost relevance. Thus, there is a constant... 相似文献
100.
Aguilar T. Carrillo-Berdugo I. Martínez-Merino P. Yasinskiy A. Rodríguez-Fernández M. Navas J. 《Journal of Thermal Analysis and Calorimetry》2021,144(3):895-905
Journal of Thermal Analysis and Calorimetry - Nanofluids are considered a promising alternative to the classic fluids used in heat transfer processes. One interesting application of nanofluids is... 相似文献