Crystalline profile

Generate profiles with constant wall thickness. Constant wall thickness in a profile makes it easier to control the thickness of the final profile and results in a more even crystallinity distribution in semi-crystalline profiles. 

Mechanism of Action The actual crystalline profile in this specific form are of sufficient size to afford a slow rate of dissolution. It is found to exert its long-acting action having an onset of action ranging between 4 to 8 hours, an optimal attainable peak varying between 10-30 hours, and its overall duration of action normally in excesss of 36 hours, which being a little longer than that of Protamine Zinc Insulin. 

Crystallinity profile measured by FTIR microscopy for variously processed PA 66 pipes [587]... 

Polarised confocal Raman microscopy was used to measure molecular orientation in uniaxially drawn PETP films, prepared with draw ratios from 1 to 3.5. The orientation of both polarised Raman microscopy and polarised attenuated total reflection IR spectroscopy. Crystallinity profiles were measured through the thickness of the film samples and compared with the orientation gradients existing in the films. This procedure was to determine whether the intuitive assumption that orientation and crystallinity would be positively correlated actually holds true on the microscopic scale for these samples. 18 refs. 

Where C is the area of the crystalline profile and A is the area of the amorphous profile. The crystalline long period D, is related to the lamellae thickness, L, by using following equation ... 

Figure 3. Crystallinity profiles for 0.31 ghm H502-25 RG fibers at two different spinning speeds. All other spinning conditions were identical.

Figure 6. Crystallinity profiles for hPP 5D49 and hPP H502-25 RG fibers spun at 1000 m/min under identical spinning conditions (0.31 ghm, 0.17 m/s quench).

The original Doufas-McHugh (1,2) two-phase microstmctural/constitutive model for stress-induced crystallization (SIC) is validated for its predictive capability using on-line Raman crystallinity and spinline tension data of two Dow homopolymer polypropylene resins. The material parameters -inputs to the model - are shown to be obtained from lab scale material characterization data oscillatory shear (DMS), rheotens and DSC. The same set of two SIC material parameters are shown to be able to predict the crystallinity profiles along the spinline and tension very well overall. The model captures quantitatively the effect of take-up speed, throughput and MFR on crystallization rate due to SIC. 

Fiber tension was measured on-line near the take-up roll with a digital tensiometer (model DTMX-200, 0.1-200 gf). The tensiometer was calibrated according to NIST standards. The calibration was confirmed by measuring the force of a 20 gm standard weight. Due to fiber movement and vibrations, the variability of the tension data was estimated to be on the order of 30% (see section 4.3). The crystallinity profiles along the spinline were measured via Raman spectroscopy as described earlier (4)... 

The effect of take-up speed on the spinline crystallinity profile at 0.31 ghm for 5D49 hPP is shown in Fig. 2. The model is shown to predict the experimental data well using the same set of material parameters (both rheological and SIC related). Increase of take-up speed results in enhancement of the crystallization rate as indicated by onset of crystallization closer to the die, implying the effects of SIC. In the absence of any effect of... 

The effect of MFR on spinline crystallinity profile at 0.31 ghm and 750 m/min is shown in Fig. 4. Increase of MFR results in slower crystallization kinetics (the onset of crystallization is at a position further away from the die). This can be explained as a consequence of SIC, since at the same processing conditions, the higher MFR material (lower viscosity) will develop less spinline stress. We should note that the model captures well the difference in crystallization rate of the 25 MFR and 38 MFR materials using the same set of material parameters (except of course for the zero-shear-rate viscosity which reflects the difference in MFR thus molecular weight). 

Figure 2. Measured and predicted crystallinity profiles along the spinline as a function of the take-up speed at 0.31 ghm for 5D49...

Ellipsometry measurements can provide infomiation about the thickness, microroughness and dielectric ftinction of thin films. It can also provide infomiation on the depth profile of multilayer stmctiires non-destmctively, including the thickness, the composition and the degree of crystallinity of each layer [39]. The measurement of the various components of a complex multilayered film is illustrated m figure Bl.26.17 [40]. 

In order to reach a crystalline state, polymers must have sufficient freedom of motion. Polymer crystals nearly always consist of many strands with a parallel packing. Simply putting strands in parallel does not ensure that they will have the freedom of movement necessary to then find the low-energy con-former. The researcher can check this by examining the cross-sectional profile of the polymer (viewed end on). If the profile is roughly circular, it is likely that the chain will be able to change conformation as necessary. 

Etch Profiles. The final profile of a wet etch can be strongly influenced by the crystalline orientation of the semiconductor sample. Many wet etches have different etch rates for various exposed crystal planes. In contrast, several etches are available for specific materials which show Httle dependence on the crystal plane, resulting in a nearly perfect isotropic profile. The different profiles that can be achieved in GaAs etching, as well as InP-based materials, have been discussed (130—132). Similar behavior can be expected for other crystalline semiconductors. It can be important to control the etch profile if a subsequent metallisation step has to pass over the etched step. For reflable metal step coverage it is desirable to have a sloped etched step or at worst a vertical profile. If the profile is re-entrant (concave) then it is possible to have a break in the metal film, causing an open defect. 

Alitame (trade name Adame) is a water-soluble, crystalline powder of high sweetness potency (2000X, 10% sucrose solution sweetness equivalence). The sweet taste is clean, and the time—intensity profile is similar to that of aspartame. Because it is a stericaHy hindered amide rather than an ester, ahtame is expected to be more stable than aspartame. At pH 2 to 4, the half-life of aUtame in solution is reported to be twice that of aspartame. The main decomposition pathways (Fig. 6) include conversion to the unsweet P-aspartic isomer (17) and hydrolysis to aspartic acid and alanine amide (96). No cyclization to diketopiperazine or hydrolysis of the alanine amide bond has been reported. AUtame-sweetened beverages, particularly colas, that have a pH below 4.0 can develop an off-flavor which can be avoided or minimized by the addition of edetic acid (EDTA) [60-00-4] (97). 

The present chapter is organized as follows. We focus first on a simple model of a nonuniform associating fluid with spherically symmetric associative forces between species. This model serves us to demonstrate the application of so-called first-order (singlet) and second-order (pair) integral equations for the density profile. Some examples of the solution of these equations for associating fluids in contact with structureless and crystalline solid surfaces are presented. Then we discuss one version of the density functional theory for a model of associating hard spheres. All aforementioned issues are discussed in Sec. II. 

We apply the singlet theory for the density profile by using Eqs. (101) and (103) to describe the behavior of associating fluids close to a crystalline surface [120-122], First, we solve the multidensity OZ equation with the Percus-Yevick closure for the bulk partial correlation functions, and next calculate the total correlation function via Eq. (68) and the direct correlation function from Eq. (69). The bulk total direct correlation function is used next as an input to the singlet Percus-Yevick or singlet hypernetted chain equation, (6) or (7), to obtain the density profiles. The same approach can be used to study adsorption on crystalline surfaces as well as in pores with walls of crystalline symmetry. 

We will use it here in order to derive an analytical form for a crystal profile with a rough interface as an exphcit example. An order parameter

crystalline phase with 0 > 0 and the gaseous (or hquid) one with 0 < 0. 

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