Pinch-off point

Fig. 12. NMOSFET operated (a) in the linear (low drain voltage) region, where S is the grounded source contact,jy is the distance from source to drain, and dis differential increase and (b) at the onset of the saturation region, V-q = V-q The point Yindicates the channel pinch-off point. For Uq point...

In the saturation region, at and above the pinch-off point, neglecting the effective channel length change due to the Vds value, due to the condition OIds/OVds = 0(thusVDs = Vgs—Vt), this equation becomes ... 

Because the drain is negatively biased, the channel depth decreases near the drain electrode as Rq increases until the depth reaches zero. As in conventional FETs this is the so called pinch-off point. Beyond the pinch-... 

Figure 16.1 Operating regimes of a unipolar FET schematic of a typical FET and graph representation of the linear regime (a), the pinch off point (b), and the saturation regime (c). (Reprinted with permission from Ref [18]).

Equation (4) corresponds to the so-called linear regime, where Vb < Vb - Vr-As Vd increases, the voltage at the drain electrode gradually decreases, up to a point where it falls to zero. This occurs at the so-called pinch off point, when Vd = Vg - Vt. Beyond pinch off, a narrow depletion zone forms next to the drain because the local potential there drops below threshold. Further increase of Vd leads to a slight extension of the depletion zone and a subsequent shift of the pinch off point towards the source. Because the potential at the pinch off point remains equal to Vg - Vr, the drain current becomes independent of the drain voltage this is the saturation regime. Here, the current is obtained by equating Vd to Vg — Vt in Eq. (4) ... 

Shuttle-type blow molding machines translate their molds linearly between the pinch-off point and the blowing station. Alternatively, it is possible to mount a series of blow molds on the circumference of a wheel (either vertical or... 

In order to discuss quantitatively the DoD droplet formation process, the positions of several representative points in the ejected liquid can be plotted as a function of time to produce the curves of the DoD droplet formation, as depicted in Figure 10. The axial distances of points 1-5 from the nozzle exit are denoted as Xi( ) to Xs( ), respectively, with measured from the first appearance of liquid from the nozzle. Initially, point 1 is the leading edge of the liquid ejected from the nozzle that later becomes the tip of the primary drop. Point 2 is the first pinch-off point of the liquid from the nozzle tip, and also the tail of the free liquid thread its first appearance corresponds to the initial breakup time bi. Points 3 and 4 are the lower and upper points produced by the second pinch-off, and the curves associated with these points initiated at the second breakup time b2) these curves form a closed loop if (in the case of a single satellite drop) the satellite recombines with the main drop (as is the case in Figure 10(a)) or may continue separately if the satellite survives as a discrete body of liquid. Later, point 3 becomes the tail of the primary drop, and point 4 becomes the head of the secondary free liquid thread or satellite. Between points 2 and 4, further pinch-off points may occur. Point 5 is the tip of liquid protruding from the nozzle orifice due to multiple reflections of the pressure wave inside the ink chamber. 

The probability that, pinch-off has occurred in a given segment of length / is approximately the same as the probability that, Ui has reached a. value greater or equal to the width of the strip W. Hence we obtain the density of pinching points at time t = 4... 

Figure 6.2-15 Wormlike nanostructures in Ge(l 11) can be obtained by partial oxidation they heal in a complex process comprising electrodeposition/electrodissolution and periphery diffusion. Ring-like defects transform to points as predicted by Grayson s theorem (vertical arrow, a 0 min, b 8 min, c 20 min - time with reference to a), electrodeposition of clusters occurs (horizontal arrows). Furthermore, the clusters can also dissolve (arrows in d-f) and pinch-off phenomena are observed (manually surrounded structures, d 0 min, e 12 min, f 52 min - time with reference to d) (picture from [60] - with permission of the Peep owner societes.

Both endocytosis of material at the plasma membrane and exocytosis from the Golgi apparatus involve the formation of clathrin-coated pits and vesicles. On the cytosolic side of the membrane these structures have an electron-dense coat consisting mainly of the protein clathrin, the polypeptides of which form a three-legged structure known as a triskelion. The clathrin triskelions assemble into a basket-like convex framework that causes the membrane to invaginate at that point and eventually to pinch off and form a vesicle. In endocytosis these clathrin-coated vesicles migrate into the cell where the clathrin coats are lost before delivering their contents to the lysosomes. 

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