Switchable second generation

Irie et al. reported on the absolute reversible photocyclization reactions of achiral diarylethene 52 in chiral crystal leading to 53 in up to 99% ee. The asymmetric photochromic material has potential application in nonlinear optics, for example, in switchable second harmonic generation devices. [32]... 

The growth and microstmcture of switchable mirror thin fllrns involves specific aspects that need to be discussed before describing their physical properties. We focus first on Y, La and rare-earth films (for convenience all abbreviated as RE films), deposited in both their metallic and hydride forms. Some references to second-generation mirrors (Mg-RE) are included and third-generation switchable mirrors (Mg-TM) are shortly discussed separately. 

Second-Generation Switchable Mirrors Magnesium-Rare Earth Films... 

Hydrogen concentration determination 98 3. Second generation switchable mirrors 226... 

The second method of improving the power factor of an installation is to provide static capacitor banks. These can be installed as a single block at the point of supply busbar, as a set of switchable banks or as individual units connected to specific loads. For an installation where no synchronous machines are installed for other purposes (i.e. as prime movers or generators) then static capacitor banks are almost invariably the most cost-effective way of improving the power factor. 

The addition of the second component therefore enhanced the gelation process for dendron A, but hindered the gelation process for dendron B. In siunmary, the gel-phase materials properties of the two dendrons responded in opposite ways to the presence of a diamine additive. This is a remarkable example in which dendritic generation and the use of a second (supramolec-ular) component can both control materials properties. This effect can be considered as orthogonal dendritic and supramolecular control. It was argued that, in the future, these systems may be exploited to develop switchable and highly controllable gel-phase materials. 

The B3 phase represents a non-switchable (probably not polar) non-tilted smectic structure with in plane positional ordering. Due to the lack of the electro-optical response it is only seldom studied. Some studies indicate second harmonic generation (SHG activity) and therefore polar structure [18], however, these measurements could not be confirmed later [19]. 

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