Video microscope

FIG. 3 (a) Block schematic of the typical instrumentation for SECM with an amperometric UME tip. The tip position may be controlled with various micropositioners, as outlined in the text. The tip potential is applied, with respect to a reference electrode, using a potential programmer, and the current is measured with a simple amplifier device. The tip position may be viewed using a video microscope, (b) Schematic of the submarine UME configuration, which facilitates interfacial electrochemical measurements when the phase containing the UME is more dense than the second phase. In this case, the glass capillary is attached to suitable micropositioners and electrical contact is made via the insulated copper wire shown. 

McQuain et al. (2003) undertook a detailed study on the effects of relative humidity and a direct comparison of fhe impacts DMSO vs. betaine in print buffer on the overall performance of quill pin printing. A video microscope was employed to visualize and track the drying behaviors of the various printing inks. A Cy5-labeled 466-bp dsDNA probe was used to monitor the printing process. Drop-drying behavior, bulk evaporation from the quill reservoir, surface tension changes, and spothng characteristics (spot diameter, spread, and number deposited) were examined at different RH levels. 

Print buffers 3X SSC, 3X SSC + 50% DMSO, and 3X SSC + 1.5 M betaine were evaluated at 40, 60, and 80% RH for spot intensity, spot diameter, intraspot variation, and CV (Figure 4.35). The reductions in quill drop volumes and droplet drying times were measured by video microscope and the quill reservoir volume changes determined by weight. In summary, "Solvent evaporation from the print buffer reservoir is the major factor responsible for the variations in the transfer of fluid to fhe slide surface."... 

Particle video microscope, PVM with high P cell Yes P, T, particle formation and agglomeration (min) 1500 psi size range 10-300 xm stirred Hydrate particle size imaging during growth/decomposition... 

CSM has coupled the FBRM with a second probe, the particle video microscope, PVM (Lasentec/Mettler Toledo), which consists of six illuminating near-infrared lasers (850 nm) that are transmitted into the sample. While the FBRM provides precise quantitative tracking of the chord lengths, the PVM probe provides qualitative images of the hydrate particle size and degree of agglomeration. The size range scale of hydrate particles that can be measured with the PVM probe is 10-300 i,m. 

Figure 2.16 CO2 bubbles nucleating from champagne at the bottom of a glass. Here, gas pockets entrapped inside cellulose particles serve as nucleation sites. The images, taken with a high speed video microscope, were kindly provided by G. Liger-Belair [37],...

Galai Dynamic Shape Analyzer DSA-10 is a complete shape characterization system for particles in motion. All particles are classified by maximum and minimum diameters, area and perimeter, aspect ratio, shape factor and more. A video microscope camera synchronized with a strobe light takes still pictures continuously of particles in dynamic flow, generating shape information on tens of thousands of particles, in the 1 to 6,000 pm range in minutes. 

Modern Raman spectrometers allow scanning of a surface up to A4 size, with XY translation stage and fine spatial adjustment to allow the operator to align the laser probe onto samples as small as 5 pm in diameter. Sample selection is assisted by the use of an integral video microscope with a rotating turret that can be fitted with up to four objective lenses to provide on-screen magnification of up to 500 X. 

In the experiments, signal transducer and activator of transcription 1 (STATl), in HeLa cells was selected for the visualized target. The experimental setup is depicted in Fig. 1. The most characteristic point of pin-fiber video-microscope is that its light source needs no interface, because it does not utilize evanescent light. Instrumentation... 

A video microscope is not required for an SECM instrument, but it is very useful and is a highly recommended addition. A video microscope is preferred over a normal optical microscope because it allows the probe to be continuously observed while operating the instrument. A video record of the experiment is also available. The video microscope aids in positioning the probe in generation/collection experiments, where the lack of a feedback response makes accurate distance control difficult. In addition, video microscopy helps in positioning the probe near features of interest on the substrate. 

Figure 11B is a modification incorporating an optical window. The window allows monitoring of tip-substrate separation with a video microscope. The window is simply a section of a microscope slide sealed against the cell using a clamp and O-ring. The cell has a square external shape to accommodate thin brass bar clamps held in place by four screws tapped into... 

Conventional SECM theory is not applicable to micropipet tips because the ratio of the glass radius to the aperture radius (RG) is typically much less than 10 [the typical RG value is 1.1 (52)]. An approach curve for facilitated transfer of potassium could only be fit to the theory for a diffusion-controlled positive feedback assuming a near-hemispherical shape of the meniscus (49). But the later video-microscopic study showed that the ITIES formed at the micropipet tip is flat (52). Neither was it possible to fit an iT — d curve obtained when a micropipet tip approached an insulator (49). Both conductive and insulting curves can be fit to the theory developed recently for small RG (53) (see Chapter 5). The theory accounting for finite kinetics of facilitated IT at the ITIES has yet to be developed. 

Fig. 30 Ethylene/propylene copolymerization (gas feed ratio 0.25) with the Ziegler-catalyst system TiCLi/AfEts/extemal donor supported on MgCl2 (0.2 MPa, 50°C) video microscopic snap-shots and kinetic evaluation of six particles...

Figure 8.42. Actin filament attached to the y-rotor by streptavidin and Fi-ATPase fixed on substrate. ATP drives counter clockwise rotation of the actin filament in 120° steps, which are directly observed by video microscope. - (Reprinted with permission...

In a video microscope, the eyepiece and the eye are replaced by a CCD array such as that used in an ordinary closed-circuit television camera. The image may be viewed directly with a video monitor, or digitized and enhanced with Si frame digitizer. 

We examined the evaporation of microdrops of water with different initial volumina on a silicon surface coated with a 30 nm thin fluoropolymer film (perfluoro-1,3-dimethylcyclohexane). The initial contact angle was = 90° and remained constant for more than half of the evaporation time. During the experiments, the temperature (T = 25 °C) and the relative humidity (RH 99%) were constant. We used a video microscope to track the dimensions of the evaporating drop from the side [23,30]. 

A typical evaporation curve of a water microdrop on a silicon cantilever, acquired at NPT and RH 30%, is a plot of the inclination of the cantilever versus time (Fig. 4A). At the same time, the contact angle and the contact radius a are recorded with a video microscope from the side (Fig. 4B and C). The water microdrop is deposited onto the cantilever at t = 0 with the inkjet device, and immediately starts evaporating. The evaporation is over after 0.6 s, as the cantilever s inclination returns to its initial value. In the contact angle and contact radius curves, the black lines are simply guides to the eye. They show that two evaporation modi take place at the beginning, the drop evaporates in the constant-contact-radius (CCR) mode, and after 0.3 s both, and a, decrease linearly with time. Plots of V and of versus time demonstrate the agreement with the evaporation law derived in Eq. 6 for a drop evaporating in non-saturated vapor (Fig. 4D). 

The two signals, inclination and resonance frequency, are acquired simultaneously, but are independent of each other. They yield the stress and the mass (Fig. 9A). We deposited a water drop on a silicon cantilever hydrophobized with a monolayer of hexamethyldisilazane (HMDS). The initial contact angle was 80°. It decreased nearly linearly during evaporation, and was 70° at the end. Tlie initial contact radius was 33 im, and decreased nearly linearly during evaporation. At the end it was below 10 xm. At present, we can record the inclination curve with a temporal resolution of 0.1 ms between data points, and the frequency curve with 5 ms. The mass calculated from the resonance frequency of the cantilever and from video microscope images is similar (Fig. 9B), although the time resolution ( 5 ms) and the sensitivity ( 50 pg) is much... 

Fig. A.9. Driving and measurement setup using video microscope...

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