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101.
A spectroscopic device for monitoring the temperature of aqueous solutions is presented. It uses a 950 nm light emission diode as light source and two photodiodes as detectors. Temperature is monitored following the thermally induced absorbance changes of the water-OH second overtone (approximately 960 nm). A linear response between the light absorbed by an aqueous solution and its temperature is found in the range from 15 to 95 degrees C. A prediction error of 0.1 degrees C and a precision of 0.07 degrees C in temperature measurement can be achieved. Up to 0.1 M of electrolyte concentration can be present in the solution without significantly affecting the temperature measurement. Different strategies, such as remote (noninvasive) or in situ (using a fiber-optic probe) temperature measurement, are shown, and their relative advantages are discussed. 相似文献
102.
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104.
Decarburized samples of grain oriented silicon steel were coated with alone and blended magnesias and submitted to the high temperature annealing. The magnesias and their blendings were characterized using granulometry measurements, ignition loss and reactivity tests. After high temperature annealing, forsterite film morphology, magnetic properties and Goss deviation were also analyzed. Better magnetic properties and sharper Goss orientation were found in samples which had used blended magnesias. These results are explained by the magnesias particle size distributions, forsterite film formation and rate of inhibitors release. 相似文献
105.
Renato Sim?es Cordeiro Wellerson Rodrigo Scarano Rejane Maira Góes Sebasti?o Roberto Taboga 《Biocell》2004,28(1):21-30
The flutamide antiandrogenic effects on the Guinea pig male prostate morphology in puberal, post-puberal and adult ages were evaluated in the present study. Daily-treated group animals received flutamide subcutaneous injection at a dose of 10 mg/Kg body weight for 10 days. The control group animals received a pharmacological vehicle under the same conditions. The lateral prostate was removed, fixed and processed for light and transmission electron microscopy. The results revealed an increase of the acinus diameter in the treated puberal animals and straitness in the stromal compartment around the acini. The epithelial cells exhibited cubic phenotype. In the post-puberal and adult animals, a decrease of the acinus diameter was observed, as well as an increase of the smooth muscle layer and presence of the folds at epithelium. The ultrastructural evaluation of the secretory cells in the treated group demonstrated endomembrane enlargement, mainly in the rough endoplasmic reticulum and Golgi apparatus. In addition, a decrease of the microvilli and alterations in the distribution patterns and density of the stromal fibrillar components were observed. In conclusion, the flutamide treatment exerts tissue effects on the lateral prostate, promoting stroma/epithelium alterations. 相似文献
106.
Kay Suenaga Rodrigo Picos Sebastià Bota Miquel Roca Eugeni Isern Eugeni García 《Journal of Electronic Testing》2007,23(6):605-612
A module to perform a built-in self-test in CMOS RF receivers is presented. The module is associated with a test strategy
consisting of measuring the main performance parameters of the single building blocks individually. Circuitry overhead, however,
is kept low by using some blocks as part of the test set-up and reusing them. The test overhead has also been reduced by replacing
direct determination of performance parameters with their estimation. The test methodology has been applied to a mixer in
the first down conversion stage of a GSM receiver, estimating its conversion gain, 1dB compression and third-order interception
points. Using the output of the IF amplifier as the only testing point, the rms errors in the estimation of the above mentioned
parameters are 1.5, 3.0 and 2.7%, respectively.
相似文献
Eugeni GarcíaEmail: |
107.
Sebastián Valenzuela Arturo Arriagada Andrés Scherman 《The Journal of communication》2012,62(2):299-314
Protest activity has become a central means for political change in Chile. We examine the association between social media use and youth protest, as well as mediating and moderating mechanisms of this relationship, using survey data collected in Chile in 2010. We found that Facebook use was associated significantly with protest activity, even after taking into account political grievances, material and psychological resources, values, and news media use. The link between overall Facebook use and protest activity was explained by using the social network for news and socializing rather than when it was used for self‐expression. Postmaterialist values and political ideologies were not found to moderate the association between Facebook use and protest. 相似文献
108.
Eduardo Sebastián Carlos Armiens Javier Gómez-Elvira 《Applied Thermal Engineering》2010,30(16):2403-2411
This paper proposes a new simplified thermal model for pyrometers, which takes into account both their internal and external physical structure and operation. The model is experimentally tested on the REMS GTS, an instrument for measuring ground temperature, which is part of the payload of the NASA MSL mission to Mars. The proposed model is based on an energy balance equation that represents the heat fluxes exchanged between sensor elements through radiation, conduction and convection. Despite being mathematically more complex than the more commonly used model, the proposed model makes it possible to design a methodology to compensate the effects of sensor spatial thermal gradients. The paper includes a practical methodology for identifying model constants, which is part of the GTS instrument calibration plan and uses a differential approach to avoid setup errors. Experimental results of the model identification methodology and a target temperature measurement performance after identification has been made are reported. Results demonstrate the good behaviour of the model, with errors below 0.15 °C in target temperature estimates. 相似文献
109.
Sebastián D'hers Eduardo N. Dvorkin 《International journal for numerical methods in engineering》2009,77(7):1015-1043
A new two‐scale finite element formulation was developed for modeling J2 plastic deformation processes (2D) in which shear band localizations take place. The formulation is based on the use of embedded strong discontinuity modes, which are triggered using a stress‐based criterion. The new formulation does not require a specific mesh refinement to model the localization phenomena and provides mesh‐independent results. The shear bands constitutive behavior is derived from the continuum properties without the introduction of any ad hoc physical law. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
110.
Jian Liu Mariavittoria Craighero Vandna K. Gupta Dorothea Scheunemann Sri Harish Kumar Paleti Emmy Järsvall Youngseok Kim Kai Xu Juan Sebastián Reparaz L. Jan Anton Koster Mariano Campoy-Quiles Martijn Kemerink Anna Martinelli Christian Müller 《Advanced functional materials》2024,34(18):2312549
Functionally graded materials (FGMs) are widely explored in the context of inorganic thermoelectrics, but not yet in organic thermoelectrics. Here, the impact of doping gradients on the thermoelectric properties of a chemically doped conjugated polymer is studied. The in-plane drift of counterions in moderate electric fields is used to create lateral doping gradients in films composed of a polythiophene with oligoether side chains, doped with 2,3,5,6-tetrafluoro-tetracyanoquinodimethane (F4TCNQ). Raman microscopy reveals that a bias voltage of as little as 5 V across a 50 µm wide channel is sufficient to trigger counterion drift, resulting in doping gradients. The effective electrical conductivity of the graded channel decreases with bias voltage, while an overall increase in Seebeck coefficient is observed, yielding an up to eight-fold enhancement in power factor. Kinetic Monte Carlo simulations of graded films explain the increase in power factor in terms of a roll-off of the Seebeck coefficient at high electrical conductivities in combination with a mobility decay due to increased Coulomb scattering at high dopant concentrations. Therefore, the FGM concept is found to be a way to improve the thermoelectric performance of not yet optimally doped organic semiconductors, which may ease the screening of new materials as well as the fabrication of devices. 相似文献