Texts for additional translation

Electroanalysis with chemically modified electrodes

(abstract)

The feasibility of using electrodes with functionalized polymer films for performing electro analysis in solution is demonstrated. The proposed approach not only takes advantage of the favorable aspects of chemically modified electrodes (e.g. sensitivity) but also provides for very broad synthetic variations (and therefore) as well as ways to detect and overcome matrix and saturation effects. The method is based on the use of copolymer films that incorporate both an electroactive center (used for inducing precipitation of the polymer on the electrode) and a coordinating site chosen on the basis of the species of interest. Even though the method is presented in the context of electroanalysis of metal ions in solution, this approach could be extended to be determination of organic functionalities through the appropriate choice of reagents.

Vocabulary

feasibility - возможность

solution - раствор

copolymer - кополимер

polymer - полимер

species - формы

precipitation - осаждение

Electric - field - induced flame speed modification

A rather large amount of works has been reported on the various effects of electric field on a wide variety of flames. However, the mechanisms responsible for the rather dramatic field-induced effects on the size and shape of the inner cone of some hydrocarbon flames is still not well understood. Bradely provides a good overview of the subject, as well as a thorough review of the literature in this general area up to the date of that’s text publication.

Electric - field - induced modifications of flame geometry have been known for some time, the first report being published by Chattock in 1889. Since then, many aspects of the effects of externally applied fields have been investigated. For example, increases in flame blow-off flow rate due to the application of external fields in both diffusion and premixed methane-air flames have been measured. Similar increases in flame stability have also been observed at fields sufficient to produce a corona discharge within the flame. Improved heat transfer to solid surfaces due to externally applied fields has been reported. Increased burning velocities for hydrocarbon flames in DC fields and elevated electron temperatures for flames in microwave fields have been similarly established. It has also been shown that soot formation in diffusion flame is diminished by application of DC external field. Flame extinction limits in premixed flame are also perturbed by DC fields. The most extensive efforts to construct and test theoretical model sufficient to predict the maximum practical effects of electric fields on flames are contained in a series of publications by Lawton and co-workers. More recently, a reaction kinetics model simulating the effects of electric fields in premixed methane flames have been used to simulate microgravity in small diffusion flames.

Vocabulary

diffusion flame - диффузионное пламя

premixed flame - предварительно смешанное пламя

corona discharge - коронный разряд

applied field - приложенное поле

application - приложение

solid surface - твердая поверхность

hydrocarbon flame - углеводородное пламя

heat transfer - передача тепла

to simulate - моделировать

DC (direct current) - постоянный ток

premixed air-methane flame - пламя, предварительно смешанных метана и воздуха; пламя смеси метана с воздухом

Experimental investigation of silane combustion and particle nucleation using a rapid- compression facility

A fixed frequency UV absorption is used to measure the concentration of the hydroxyl radical and the rapid-compression facility is used to generate the elevated temperature conditions characteristics of ignition and particle nucleation in the silicon / oxygen system. A detailed description of the rapid-compression facility, the operating procedures and the results of benchmark experimental studies characterizing performance can be found in Donovan’ s work. A schematic of the rapid-compression facility is shown in Fig. 1. Briefly, the rapid-compression facility consists of: the driver section, the test manifold, the sabot (free-piston) and the hydraulic control value assembly, and in its most basic form can be described as a simple piston - cylinder device. The driver section acts as a reservoir for high-pressure gasses used to operate the rapid-compression facility and is connected to the driven section by a fast- acting globe valve. The driven section is the cylinder through which the sabot travels during operation (the sabot is located into the globe valve end of the driven section) and is connected to the test manifold at its other end. Test gases are loaded into the middle of the driven section prior to operation. During operation, the globe valve is opened (using hydraulic valve assembly), permitting the compressed gas to enter the driven section and rapidly accelerate the sabot.

Vocabulary

absorption - абсорбция

hydraulic valve assembly - сборка гидроклапана

valve - клапан

globe valve - шаровой клапан

test manifold - тестирующее устройство