We present a comprehensive theory of nuclear spin polarization of He and Xe gases by spin-exchange collisions with optically pumped alkali-metal vapors. The most important physical processes considered are ~1! spin-conserving spin-exchange collisions between like or unlike alkali-metal atoms; ~2! spin-destroying collisions of the alkali-metal atoms with each other and with buffer-gas atoms; ~3!...

Soil salt-alkalization is a major limiting factor for crop production in many regions. Switchgrass (Panicum virgatum L.) is a warm-season C4 perennial rhizomatous bunchgrass and a target lignocellulosic biofuel species. The objective of this study was to evaluate relative alkali-salt tolerance among 30 switchgrass lines. Tillers of each switchgrass line were transplanted into pots filled with f...

the conversion of the cellulose into 5-hmf would experience three steps, cellulose to glycose, glycose to fructose and fructose to 5-hmf. chloride ion can break down the hydrogen bond in cellucose, chromium can catalyze the isomerization of glycose to fructose, and the high temperature is helpful to cyclohydration of fructose to 5-hmf. in this paper, the sawdust has been directly degraded into ...

in this study, a temperature-dependent of the dispersion coefficients is calculated from equation state.the lennard-jones lj (12-6-3) effective pair potential function and simple thermodynamic argumentwith the input pvt data of liquid metals are used to calculate the dispersion coefficients. the dispersioncoefficients ( , , ) 3 6 12 c c c are found to be a linear function of 1/t1+α , where t is...

a simple, rapid and sensitive spectrophotometric method has been proposed for the determinationof vanadium (iv). the method is based on the catalytic effect of v (iv) on the oxidation of alkali blue bypotassium bromate at ph 4. the rate of decrease in the absorbance of alkali blue (at 572 nm) wasproportional to the concentration of v (iv) in the range of 100-6000 ng ml-1. the detection limit wa...

We show that alkali metals function as effective modifiers of calcium oxalate monohydrate (COM) crystallization wherein alkali-oxalate ion parings reduce the rate of crystal growth by as much as 60%. Our findings reveal a distinct trend in alkali metal efficacy that cannot be explained by colloidal theories or simple descriptors, such as ion size, but is consistent with a theoretical model that...

purpose : studies show that phenytoin is effective in improvement of different chronic ulcers such as venous stasis ulcers, and diabetic ulcers. the exact mechanism is yet not clear investigators thought that phenytoin might help to heal intractable corneal ulcers by reducing inflammation, differentiating limbal fibroblasts, and promoting the invasion of the cornea with new blood vessels as sho...