Electron curtain

Figure 5.1 Schematic diagrams of (a) a scanned-beam electron accelerator and (b) an electron-curtain accelerator. Adapted with permission from Ref [1] 1993, Elsevier.

The most frequently encountered hydrolysis reaction in drug instability is that of the ester, but curtain esters can be stable for many years when properly formulated. Substituents can have a dramatic effect on reaction rates. For example, the tert-butyl ester of acetic acid is about 120 times more stable than the methyl ester, which, in turn, is approximately 60 times more stable than the vinyl analog [16]. Structure-reactivity relationships are dealt with in the discipline of physical organic chemistry. Substituent groups may exert electronic (inductive and resonance), steric, and/or hydrogen-bonding effects that can drastically affect the stability of compounds. A detailed treatment of substituent effects can be found in a review by Hansch et al. [17] and in the classical reference text by Hammett [18]. 

Even simple tasks like closing the curtains when the sun shines into a room or lowering the temperature when nobody is in the house can lead to substantial saving of 20-30% on the utility bill. Electronic faucets are not only more hygienic but also save water through the use of time out settings and low-flow aerators (see Fig. 6.9). 

In contrast, a new type of redox polymer-coated electrode has recently been fabricated using the bottom-up method, in which redox-active molecules are connected with molecular wires, and the wires act as the current collector.11-13 In this case, electrons can be transported through the wires, and control of the electron transfer pathway is possible by changing the structure of the molecular wires. If the wire has a linear structure, redox active molecules with the wire connections exhibit a structure similar to that of a beaded curtain (Fig. lb), in which the electron transfers in a straightforward manner along each line. Furthermore, when the wire is composed of redox active molecules, we observe the promising phenomenon that the electron transfers via the redox process in the wire, whose mechanism would... 

All conversions measured for thin films (type laboratory electron processor. 

Retardants are mainly used as additives for plastics, particularly those used in the manufacture of electrical and electronic equipment. FRs are added to circuit boards, cables, coimectors, plugs, and house component devices. These compounds are used in the production of engineering plastics, thermoplastic and elastomeric elements, and insulation. Flame retardants can also be found in furniture, mattresses, carpets, curtains, clothing (mainly protective or sweatshirts for children), and polymeric materials used for the production of cars, buses, airplanes, and military equipment. FRs have been used wherever material must meet safety standards regarding flammability [87]. 

In the apartment George White took in San Francisco, the CIA moved in so much electronic surveillance equipment that one former agent was later to remark if you spilled a glass of water, you d probably electrocute yourself .19 White brought his own peculiar flair to the place, furnishing it like a caricature brothel—red curtains,... 

Figure 26. Spectrum and electron distributions extracted from Fig. 25. The curtain edge is particularly clearly seen at ionization energies between real dication states in this as in all other cases the edge position exactly matches an atomic ion excited level.

Detector MS, Perkin Elmer Sciex API Ill-Plus triple quadrupole, APCI, nebulizer 400° and 80 psi, auxiliary nitrogen 1.2 L/min, curtain gas 1.2 L/min, interface 55°, collision gas argon, electron multiplier 3000 V, declustering potential 35 V, collision energy 35 eV... 

Detector MS, PE Sciex API III, heated nebulized interface, corona discharge needle +4 xA, nebulizer probe 500°, nebulizing gas was air at 2 L/min and 80 psi, curtain gas flow was nitrogen at 0.9 L/min, sampling orifice +45 V, dwell time 400 ms, interface heater 60°, electron multipher-3.7 kV, collision gas was argon 355 x 10 atoms/cm, first quad-rupole filter admits m/z 276 (cyclobenzaprine) and 295 (trimipramine, collisional fragmentation at second filter, monitor m/z 215 (cyclobenzaprine) and 208 (trimipramine) at third quadrupole filter... 

Detector MS, PE-SCIEX API III triple quadrupole, heated nebulizer, corona discharge (+5 pA), positive ion APCI, nebulizer probe 500°, collision gas argon at 350 X 10 mole-cules/cm, nebulizing gas nitrogen at 80 psi and 2 L/min, curtain gas nitrogen at 0.9 L/min, orifice -1-50 V, electron multiplier -3.8 kV, dwell time 400 ms, interface heater 60°, m/z 317... 

Electron-Beam Curing. The equipment used in th s study was an Electro-curtain curing unit from Energy Sciences Inc., Massachusetts, USA and was located at Lankro Chemicals Limited, Manchester, UK. 

Figure 1. Schematic view of a curtain-type selfshlelded electron processor. The product path typically Involves a modest angle change to facilitate radiation shielding. An Inert gas knife coupled with a small process volume eliminates oxygen Inhibition and ozone generation problems. Process speeds to 300 m/mlnute are typical.

Electron beams are generated by applying an accelerating voltage (150 kV) to a thermionic cathode. An electron beam (ca. 6 mm diameter) is spread out into a curtain beam by a beam splitter. The electrons leave the beam distribution housing through a very thin metal sheet. When these electron beams strike binder monomers, they initiate polymerization in the paint film. Polymerization occurs in a fraction of a second and must be performed in a vacuum or in an inert gas atmosphere. The equipment must be screened to protect the operators. 

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