Fast measurement

Bassi et al. [70] have described IMR-MS for online gas analysis with a sensitivity of 100ppb-l ppm. A mass-selected ion source allows the use of three different primary ion beams (Xe+, Kr+ and CF3I+), covering the recombination energy range from 10.23 to 14.67 eV. For fast measurements, the change from one primary ion to another can be achieved by a Wien filter. IMR-MS allows quantitative analysis. 

Such electrodes should be sufficient as a reference electrode for short-term usage or as a disposable electrode. However, the requirement of a pre-hydration time may limit its applications for fast measurements, such as POCT (the point-of-care testing), due to its slow response time. In fact, the lack of long-term stable microreference electrodes will continue to hamper the development of integrated pH sensing systems. 

Air quality measuring systems that detect for example the leading substance C02 (refer to chapter 53.3.3) do not require the high accuracy of expensive measuring systems. Therefore, not much effort needs to be put in the development and construction of C02 detectors. In general the accuracy of such systems amounts to 10%, which is achievable for the cost of an electrochemical cell. Fast measurements aren t needed but nevertheless averaging to increase accuracy is possible and recommended. 

By using pulsed laser sources and fast measuring devices, direct observation of redox products in flash photolysis experiments provides evidence regarding oxidative and reductive quenching mechanisms in Ru(bpy)3+. 

Our examples above demonstrated this quantitatively. For this reason, it is vital to design a reactor control system with very fast measurement dynamics and very fast heat-removal dynamics. If the thermal lags in the temperature sensor and in the cooling jacket are not small, it may not be possible to stabilize the reactor with feedback control. 

Wang, J., and Ghen, G. (2003). Microchip capillary electrophoresis with electrochemical detector for fast measurements of aromatic amino acids. Talanta 60, 1239—1244. 

Wang, J., M. Pumera, and G. Collins. A chip-based capillary electrophoresis-contactless conductivity microsystem for fast measurements of low-explosive ionic components. Analyst 127, 719-723 (2002). 

For low coating rates, small densities of the coating material and fast measurements (that require short counting times), it is important to have a reference oscillator with a high frequency. All of this requires great time precision so that the small coating-related frequency shifts can be resolved. If the frequency shift of the monitor crystal decreases between two... 

The pulse radiolysis method has been described in detail in some of the early papers (22, 22), in a brief review of the subject (23), and in a current comprehensive review (14). It is, in brief, a fast reaction method in which the external perturbation applied to the system is a microsecond pulse of electrons. The current is sufficiently high to produce an instantaneous concentration of transient species high enough to be observed by fast measurement of the optical absorption. Spectra may be recorded either photographically or spectrophotometrically. The kinetics are studied by fast spectrophotometry. Since a perturbing pulse as short as 0.4 /xsec. has been used, the time resolution has approached 10-7 sec. The flash photolysis method used in some of the other studies (27, 15) has been reviewed in detail (24). 

Balancing a bridge is a rather slow process, so the method cannot be used to follow a rapidly changing solution resistance (as encountered in kinetic measurements). A number of circuits reported in the literature102 104 allow the resistance of a solution to be recorded continuously. A method that employs the successive application of constant-current pulses of equal magnitude, but of opposite sign, has been described, which works well in both low-resistance and high-resistance solutions (< 100 kQ) and is well suited to the fast measurement of solution resistances."... 

Flash converters are mainly used in very fast measurement devices with low to medium requirements on resolution (e.g. digital sampling oscilloscopes or video digitizers). 

IR spectroscopic imaging offers the advantage of fast measurements with lateral resolution of a few micrometers. Due to the high acquisition rate of spectral data even dynamic systems can be studied at a time resolution of seconds. This report will demonstrate the unique opportunities by FTIR spectroscopic imaging to investigate material characterized by small thickness of the sample layer and non-crystalline state. SPR imaging is a new technique based on the classical SPR that combines high sensitivity with excellent lateral reso-... 

The use of galvanostatic transients enabled the measurement of the poten-tiodynamic behavior of Li electrodes in a nearly steady state condition of the Li/film/solution system [21,81], It appeared that Li electrodes behave potentio-dynamically, as predicted by Eqs. (5)—(12), Section III.C a linear, Tafel-like, log i versus T dependence was observed [Eq. (8)], and the Tafel slope [Eq. (10)] could be correlated to the thickness of the surface films (calculated from the overall surface film capacitance [21,81]). From measurements at low overpotentials, /o, and thus the average surface film resistivity, could be measured according to Eq. (11), Section m.C [21,81], Another useful approach is the fast measurement of open circuit potentials of Li electrodes prepared fresh in solution versus a normal Li/Li+ reference electrode [90,91,235], While lithium reference electrodes are usually denoted as Li/Li+, the potential of these electrodes at steady state depends on the metal/film and film/solution interfaces, as well as on the Li+ concentration in both film and solution phases [236], However, since Li electrodes in many solutions reach a steady state stability, their potential may be regarded as quite stable within reasonable time tables (hours —> days, depending on the system s surface chemistry and related aging processes). 

Modern frequency meters allow fast measurements with good resolution, i.e., 60 ms (Philips PM6654) or 100 ms (HP5384) for 0.1 Hz resolution. The ultimate resolution of the QCM is limited, however, to miliseconds by the time required in equilibrating the crystal with the deposited mass, which is determined by the operating frequency and the quality factor of the QCM [3]. 

Washing-, rubbing- and light fastness of the dyed PET fibers at different temperatures were also tested. All fastness measurements of the dyed samples with C02PES MARINE SM1F gave very good results. 

The cavities we use are completely disassembled after deposition. Measurement of the film thickness profiles can then be done by very different techniques. For sufficient film thickness a very convenient and fast measurement... 

In order to understand whether the observed differences were ascribable to any effect of the mycelia on the reaction equilibrium, a series of measurements was aimed at monitoring the variations in the water vapour pressure in the gas phase, expressed as relative humidity (RH). A hygrometer specifically conceived for providing fast measurements in systems involving organic solvents was used for this. 

Recent advances in ultrasonic resonators have facilitated the development of Inexpensive, convenient devices for fast measurement of ultrasonic velocity and attenuation in small volumes (down to 0.1 ml) with resolution better than 10 % for velocity and 0.1% for attenuation. In addition, comprehensive studies on ultrasonic parameters of liquids in a number of laboratories over the last decade have provided a solid background for the interpretation of ultrasonic data. 

When adsorption from solution Is monitored by the depletion method. It Is very difficult to measure changes in bulk concentration over time Intervals down to milliseconds. Perhaps this Is the reason that such systematic studies are not abundant in the literature. Fast measurements require stopped-flow, pressure-jump or temperature-jump techniques. The method used to determine concentrations must also be fast suitable methods include certain spectroscopies and, for charged substances, conductivity. When adsorption on Fresnel surfaces Is studied, say by reflectometry, concentration measurements in the solution are not needed. 

E. Robens, C.H. Massen, J.A. Poulis, P. Staszczuk Fast measurements of adsorption on porous materials using Jantti s method. Adsorption Sci. and Tech. 17 (1999) 10, 801-804. 

We proposed a novel method which can be used to for fast measurements of infinite dilution selectivity in binary gas adsorption. This experimental system can handle a wide range of pressure variation. Using the data obtained one can perform a quick characterization for selectivity. From the design point of view this method can be effectively employed to check validity of the model being used. 

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