Vacuum under

The simplest system in which useful products are obtained by thermochemical processing involves the evaporahon of an element or elements in vacuum in order to produce thin hlms on a selected substrate. This process is usually limited to the production of thin hlms because of the low rates of evaporation of the elements into a vacuum under conditions which can be controlled. These rates can be calculated by the application of the kinetic theory of ideal gases. 

U4 Dry over CaCl2 and distil in a vacuum under N2. [Hiickel and... 

Dilongifolyl borane [77882-24-7] M 422.6, m 169-172 . Wash with dry Et20 and dry in a vacuum under N2. It has m 160-161 in a sealed evacuated capillary. It is sparingly soluble in pentane, tetrahydrofuran, carbon tetrachloride, dichloromethane, and chloroform but the suspended material is capable of causing asymmetric hydroboration. Disappearance of solid indicates that the reaction has proceeded. [J Org Chem 46 2988 1981.]... 

The vast majority of metallic bonded assemblies are cured in autoclaves. A small number are cured using mechanical pressure application devices (clamps, presses) or by drawing a vacuum under a bag over the part in an oven. Mechanical pressure is rarely used for a few reasons. For all but completely flat assemblies it... 

The propagator K can be interpreted as the Green s function for computing amplitudes for one-particle processes relative to the amplitude that the vacuum remain a vacuum under the influence of the external potential. To lowest order the amplitude that the vacuum remain a vacuum is given by... 

Polymer Synthesis and Characterization. This topic has been extensively discussed in preceeding papers.(2,23,24) However, we will briefly outline the preparative route. The block copolymers were synthesized via the sequential addition method. "Living" anionic polymerization of butadiene, followed by isoprene and more butadiene, was conducted using sec-butyl lithium as the initiator in hydrocarbon solvents under high vacuum. Under these conditions, the mode of addition of butadiene is predominantly 1,4, with between 5-8 mole percent of 1,2 structure.(18) Exhaustive hydrogenation of polymers were carried out in the presence of p-toluenesulfonylhydrazide (19,25) in refluxing xylene. The relative block composition of the polymers were determined via NMR. 

Compared with PET, PEN has five times more radiation resistance in air, four times more in O2 and ten times more resistance in vacuum under continuous-use temperature [10]. Cakmak and co-workers calculated the refractive index of PEN this parameter is highest (nc = 1.908) along the chain axis and lowest (nn = 1.36) normal to the naphthalene ring. Biaxially oriented PEN film has a... 

FIG. 15. A comparison between the distance dependence of the tunneling barrier between a jellium tip and substrate immersed in solution versus vacuum under zero bias conditions. The apparent barrier height is derived from the WKB approximation. (From Ref. 110.)... 

Thermal Stability. Lithium-ion batteries can be poisoned by water, and so materials going into the cell are typically dried at 80 °C under vacuum. Under these conditions, the separator must not shrink significantly and definitely must not wrinkle. Each battery manufacturer has specific drying procedures. The requirement of less than 5% shrinkage after 60 min at 90 °C (in a vacuum) in both MD and TD direction is a reasonable generalization. 

The molar mass of the products is very dependent on the final conversion achieved and thus, on the final quality of the vacuum. Under the described conditions number average molar masses as determined by GPC in DMAc/LiCI (3 g/l)/water (2 vol%) will reach values between 2,000-5,000 g/mol. 

Molybdenum disulfide is mined from natural molybdenite deposits. The compound also can be made by direct combination of elements i.e., heating molybdenum and sulfur at elevated temperatures and under vacuum. Under such conditions, other sulfides of molybdenum that may have formed convert to the more stable disulfide. 

Di-n-butyl boron triflate (di-n-butylboryl trifluorosulphonate) [60669-69-4] M 274.1, b 37°/0.12mm, 60°/2mm. Distil in vacuum under argon and store under argon. Should be used within 2 weeks of purchase or after redistn. Use a short path distn system. It has IR bands in CCI4 at v 1405, 1380, 1320, 1200 and 1550cm- and 3c NMRfCDCb) with 8 at 118.1, 25.1, 21.5 and 13.6ppm. [Org Synth 68 83 7990 JACS 103, 3099 7957]. 

The material to be evaporated is placed in a sample holder. Frequently, these sample holders are indented strips of W, Ta, or Mo, or wire baskets of the same metals, or carbon crucibles. These sample holders can be heated resistively by passing a large current through them, thus melting and then volatilizing the material. Alternatively, the sample holder can be bombarded by low-energy electrons to heat the sample. The entire process takes place in vacuum. Under reduced pressure, most... 

We consider the problem of motion of a gas adjacent to a vacuum under the influence of a short pressure impulse. 

Maximum chamber vacuum under no load Chamber leak rates under vacuum and pressure Shelf temperature control (i.e., temperature variation)... 

The reaction is performer at 230 K. When the reaction mixture is warmed at room temperature, the starting material is re-formed almost quantitatively (960M872). If the reaction mixture is taken to dryness at low temperature under high vacuum (under conditions where HC1 is removed), the last product is relatively stable at room temperature. In 2,5-dimethylthiophene/THF (1 1) the ratio of the products is 1 1 1. 

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