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51.
V Atanasiu I Niculescu O Niculescu S Iacoban E Trutia 《Canadian Metallurgical Quarterly》1997,34(1-4):137-143
Spectrophotometric assays have been used to determine FA concentration in tissue homogenates from various organs (liver, kidneys, brain, spleen) in white rats; these studies were undertaken to test the age--and organ--dependent variations of FA concentrations in tissue homogenates. The results showed a marked decrease of FA concentration in the adult group of rats when related to the young group, and in the aged group when compared to the adults respectively. Analysing the determined values of folates in tissue homogenates of various organs (in rats belonging to the same group of age), the highest concentration has been found in the liver homogenate, followed in decreasing order by kidneys and to a much greater distance, by the brain and spleen. 相似文献
52.
Spectral analysis of optical mixing measurements 总被引:1,自引:0,他引:1
Nazarathy M. Sorin W.V. Baney D.M. Newton S.A. 《Lightwave Technology, Journal of》1989,7(7):1083-1096
A general rigorous theory of optical heterodyne and homodyne measurements is presented. The power spectrum of the photocurrent resulting from two uncorrelated optical beams mixing on a photodetector is derived. In particular, a rigorous analysis is presented for the delayed self-homodyne method which is used to characterize laser source linewidth by a Mach-Zehnder interferometer with a delay exceeding the source coherence length. Existing treatments are generalized to address non-Lorentzian laser sources of arbitrary lineshape. The analysis is further generalized to cover the case of modulated nonstationary sources. An example of the application of this theory is given. It is shown how the theory may be used to interpret an experimental result obtained using the gated delayed self-homodyne technique for characterizing the frequency chirp of laser sources under modulation 相似文献
53.
The mixing of a modulated DFB laser with a CW local oscillator can be achieved with a single laser by using a gated modulation technique combined with an appropriate optical delay. Frequency chirp measurements up to ±22 GHz are demonstrated using this technique 相似文献
54.
We tested the intraoral microwaves under applied electrotherapy in cephalic neuralgia. The tests have been undertaken on 40 patients divided in 4 groups, according to the nature of the metallic components of the prosthetic appliances. There have been withdrawn practical conclusions regarding fixed prosthesis and the use of electrotherapy in the cephalic neuralgia. 相似文献
55.
The implementation of a natural language manmachine dialogue in a data base or knowledge base query system is a difficult task. We present hereafter three different approaches to this problem : dialog modeling, exemplified through a linguistic scheme and several computational implementations ; the cooperation principles in a dialog and their associated algorithms ; and, lastly, the artificial intelligence approach based on speech acts theory and the techniques for generating and recognizing plans. We conclude by assessing the possible use of current speech processing techniques and by listing still unsolved problems. 相似文献
56.
Silver nanoparticle thin layers were deposited onto formaldehyde‐radio frequency (RF)‐plasma‐functionalized medical‐ and food‐grade silicone rubber, stainless steel, and paper surfaces. The silver deposition was carried out under ex situ plasma conditions using the Tollen's reaction. Results from survey and high‐resolution electron spectroscopy for chemical analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X‐ray spectroscopy investigations confirmed the presence of thin silver layers on the plasma‐exposed and subsequently modified substrate surfaces. In addition, SEM and AFM demonstrated the nanoparticle‐based morphology of the deposited layers. Our results showed that thin macromolecular layers bearing aldehyde functionalities can be deposited onto silicone rubber, stainless steel, and paper surfaces. The bactericidal properties of the silver‐coated surfaces were demonstrated by exposing them to Listeria monocytogenes. No viable bacteria were detected after 12 to 18 h on silver‐coated silicone rubber surfaces. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1411–1422, 2004 相似文献
57.
Effects of working parameters on surface finish in ball-burnishing of hardened steels 总被引:4,自引:1,他引:4
Burnishing is a chipless finishing method, which employs a rolling tool, pressed against the workpiece, in order to achieve plastic deformation of the surface layer. Recent developments made possible burnishing of heat-treated steel components up to 65 HRC. Features of burnishing include a good roughness (comparable to grinding), as well as improvement of mechanical characteristics of the surface (fatigue strength, corrosion resistance, and bearing ratio), due to implementation of compressive stresses into the surface layer. This paper will present influences of certain burnishing parameters upon roughness, for a hardened steel component (64 HRC). 相似文献
58.
Maria Elena Zarif Saa Alexandra Yehia Bogdan Bi Veronica Stulu Sorin Vizireanu Gheorghe Dinescu Alina Maria Holban Florica Marinescu Ecaterina Andronescu Alexandru Mihai Grumezescu Alexandra Ctlina Bîrc Alexandru Titus Farcaiu 《International journal of molecular sciences》2021,22(23)
Despite the technological progress of the last decade, dental caries is still the most frequent oral health threat in children and adults alike. Such a condition has multiple triggers and is caused mainly by enamel degradation under the acidic attack of microbial cells, which compose the biofilm of the dental plaque. The biofilm of the dental plaque is a multispecific microbial consortium that periodically develops on mammalian teeth. It can be partially removed through mechanical forces by individual brushing or in specialized oral care facilities. Inhibition of microbial attachment and biofilm formation, as well as methods to strengthen dental enamel to microbial attack, represent the key factors in caries prevention. The purpose of this study was to elaborate a cold plasma-based method in order to modulate microbial attachment and biofilm formation and to improve the retention of fluoride (F−) in an enamel-like hydroxyapatite (HAP) model sample. Our results showed improved F retention in the HAP model, which correlated with an increased antimicrobial and antibiofilm effect. The obtained cold plasma with a dual effect exhibited through biofilm modulation and enamel strengthening through fluoridation is intended for dental application, such as preventing and treating dental caries and enamel deterioration. 相似文献
59.
The problem of regulating an uncertain and/or time-varying linear discrete-time system with state and control constraints to the origin is addressed. It is shown that feasibility and a robustly asymptotically stable closed loop can be achieved using an interpolation technique. The design method can be seen as an alternative to optimization-based control schemes such as Robust Model Predictive Control. Especially for problems requiring complex calculations to find the optimal solution, the present method can provide a straightforward suboptimal solution. A simulation demonstrates the performance of this class of constrained controllers. 相似文献
60.
Baiyan Dong Sorin Manolache Eileen B. Somers Amy C. Lee Wong Ferencz S. Denes 《应用聚合物科学杂志》2005,97(2):485-497
Polyethylene glycol (PEG) structures were deposited onto stainless steel (SS) surfaces by spin coating and argon radio frequency (RF)‐plasma mediated crosslinking. Electron spectroscopy for chemical analysis (ESCA) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) indicated the presence of CH2 CH2 O structure and C C C linkage, as a result of the plasma crosslinking, on PEG‐modified SS surfaces. Scanning electron microscopy (SEM) indicated complete deposition, and water contact angle analysis revealed higher hydrophilicity on PEG‐modified surfaces compared to unmodified SS surfaces. Surface morphology and roughness analysis by atomic force microscopy (AFM) revealed smoother SS surfaces after PEG modification. The evaluation of antifouling ability of the PEG‐modified SS surfaces was carried out. Compared to the unmodified SS, PEG‐modified surfaces showed about 81–96% decrease in Listeria monocytogenes attachment and biofilm formation (p < 0.05). This cold plasma mediated PEG crosslinking provided a promising technique to reduce bacterial contamination on surfaces encountered in food‐processing environments. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 485–497, 2005 相似文献