Crystallization improving

Not all space-grown biomolecular crystals were superior to those grown on Earth, but there were a number of cases of larger crystals, improved diffraction resolution, and lower mosasicity to merit a serious study among theorists to investigate how gravity... 

The chemical stability of pentaerythritol tetranitrate is very high and exceeds that of all other nitric add esters. It withstands the heat test at 80°C for several hours. As heating continues decomposition is gradually perceptible at temperatures above the melting point, i.e. above 140°C. Aubertein and Rehling [21] have found that water is occluded in crystals of PETN purified by recrystallization from acetone-water. The presence of these occlusions has an adverse effect on the results obtained by examinii the stability of penthrite at 132°C. Removal by grinding and drying the crystals improves the result of the stability test. 

Obviously a small wave velocity in the crystal improves the mass sensitivity of the sensor for a given mechanical resonance frequency/), whereas a large wave velocity increases the mass sensitivity if thickness of the crystal must not fall below a specific value. Table 1 illustrates these basic findings for AT-cut (exemplarily for a small Vq) and BT-cut quartz (exemplarily for a high Vq) for two cases a lOOnm rigid film (Sauerbrey case) and a semi-infinite hquid with a viscosity of 1 cP (Kanazawa case). 

Besides frequency increases, another way that some investigators have increased the mass sensitivity of standard QCM crystals is by modifying the metal surface of the crystal. Improvements in mass sensitivity of > 2.5-fold have been measured using micromachined surfaces [13] and for electrode-posited gold surfaces that increase the surface area due to increased porosity [14]. For a process where the effective surface area is the limiting factor in mass sensitivity, the latter type of approach is of particular importance for future applications. It remains to be determined whether a systematic examination of creating microscale or nanoscale surface features on the upper electrode of the QCM crystal can reveal as yet unobserved increases in mass sensitivity. 

Improved Crystallization improvement in the form and appearance of crystals can be observed by visual inspection. Improvement in color is determined by dissolving the crystals in a suitable solvent and measuring the color of the solution. The extent to which a yield of crystals is increased by carbon treatment is difficult to measure accurately in laboratory experiments. Such information should be derived from plant experience. 

Li,Y.,Wang,Y.,Liu,L,Han,L.,Xiang,F.,andZhou,Z.(2009).Crystallization improvement of poly(L-lactide) induced by functionalized multiwalled carbon nanotubes. I. Polvm.. 9c/. Part B Polvm. Phvs.. 47, 326-339. 

Chem. Descrip. Nonylphenol disulfide oligomer Uses Antioxidant tor disproportionation and bleaching rosins and rosin ester, enabling prod, of lighter colored resins for use as adhesive tackitiers and clear coatings (varnishes) decreases tendency of rosins to crystallize improves stability and lightens color of rosin esters Properties Dk. brn. vise, liq. mild sulfur odor sol. in common org. soivs. (methanol, heptane, toluene) sol. < 1% in water sp.gr. 1.03 (15.6 C) vise. 24-34 cSt (100 C) 9.4-10.6% sulfur Ethazate [Uniroyal]... 

Defect-free membranes comprising zeolites and amorphous glassy perfluoropolymers can be prepared by modifying the surface of the filler. The pure gas permeation experiments of a series of Teflon AF 1600 membranes with various amounts of 80 and 350nm silicalite-1 crystals cannot be interpreted on the basis of the Maxwell model, but are compatible with a model in which a barrier to transport exists on the zeolite surface and a lower density polymer layer surrounds the crystals. With a small zeolite size (80nm) the low density layers around the crystals may coalesce and form percolation paths of lesser resistance and less selectivity. Silicalite-1 crystals improve the CO2/CH4 selectivity of Hyflon AD60X, and drive the N2/CH4 selectivity beyond the Robeson s upper bound. It also turns out that the presence of silicaUte-l crystals, like fumed silica, promote the inversion of the methane/butane selectivity of Teflon AF2400 in mixed gas experiments. 

Solids occur in the form of crystals when the atoms and molecules within the bulk are arranged in an ordered manner to form a definite geometrical pattern or shape. This arrangement gives rise to a pure form of the solid since impurities will not fit into the spaces and are rejected. The formation of crystals by a crystallization process is, therefore, often used to produce pure chemicals. Furthermore, crystallization improves the appearance of chemicals, makes handling, and often drying, easier. 

Outstanding properties accelerates crystallization, improves physical and mechanical properties, improves resistance to heat deformation, impact resistance, shortens product cycle time and improves production efficiency... 

Outstanding properties accelerates crystallization rate, heterogeneous nucleator, P-nucleator, clarifier, induces crystal growth in the polymer, improves mechanical properties, enhances clarity through haze reduction, reduction of cycle time up to 25% in injection molding, excellent thermal stability, low volatility and color stability, increases temperature of crystallization, improves stiffness and transparency... 

Potential applications have been identified for the use of EAN with proteins, such as dissolving hydrophobic ligands (e.g., ferrocene) to incorporate them into a protein crystal, improved solubility of some proteins, improved monodis-persity of proteins, as a precipitating agent, and as an additive. ... 

Increased orientation and rate of crystallization improve light transmission. As a consequence, increasing drawing and blowing ratios improve clarity. 

Enantiopure sulfinimines are ammonia imine synthons useful in the asymmetric synthesis of amines and -amino acid derivatives. Sulfinimines unavailable via the Andersen synthesis (R = H) are prepared hy asymmetric oxidation of the sulfenimines, ArS-N=C(R)PhX, with (+)-( ) or (-)-(1) at -20 to 20 °C in CCI4 (eq 8). Crystallization improves the ee to >95%. The sulfoxide chiral recognition model correctly predicts the configuration of the product. 

Note that the readout scheme for the PEP-II detector will use two diodes per crystal, improving the noise performance by /2 over the single diode results discussed here. This is more than an order of magnitude lower than the 500keV/crystal electronic noise at CLEO II [8], leading to a significant improvement in the expected energy resolution below 200 MeV. 

The polarization enhancement by La substitution can be attributed to crystallization improvement of the thin films which has been confirmed by XRD and SEM. In addition. 

---