Density, dielectric and X-ray studies of Smectic A-Smectic A transitions

We report here the results of detailed density, dielectric and X-ray studies on three systems exhibiting different types of Smectic A-Smectic A transitions. It is found that although the layer spacing shows marked changes at the transitions, the corresponding density changes are extremely small. In every case studied, the dielectric anisotropy shows a pronounced decrease on going over to the lower temperature smectic A phase. This decrease can be correlated with the structural changes

Environmental Response and Genomic Regions Correlated with Rice Root Growth and Yield under Drought in the OryzaSNP Panel across Multiple Study Systems

Funding: This research was funded by the Generation Challenge Program (GCP) project G3008.06, “Targeting Drought-Avoidance Root Traits to Enhance Rice Productivity under Water-Limited Environments". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Self-assembling phospholipid tubules

Lipid-based tubules serve as models for the development of advanced materials based upon molecular self-assembly. The processes by which tubules are formed and how they are coated with metals (nickel in the Figure) or used as templates in order to increase the strength of the final material are described. Their electrical and magnetic properties are discussed

DTC Technique for Induction Machine based Integrated Starter-Generator of an Automobile

This paper mainly concentrates on the application of the direct torque control (DTC) technique for the induction machine based integrated startergenerator (ISG) for automobile applications. It also discusses in brief about the higher DC bus voltage requirements in the automobiles i.e. present 14V system vs. 42V system to meet the power requirements, modes of operation of ISG, electric machine and the drive selection for the ISG,description of DTC technique, simulation and experimental results, and implementation

Photo-dimerized monolayer (PDML) versus rubbed polyimide (RPI): a comparison of electro-optic properties

Electro-Optic response characteristics as well as polar anchoring energies of liquid crystal cells prepared using a new photo-alignment technique i.e., photo-dimerized monolayer, have been measured. These data are compared with those for cells that use a rubbed polyimide alignment layer. The two alignment methods yield comparable electro-optic properties showing thereby that the new photo-alignment technique is a viable alternative to the rubbed alignment technique for display applications

Novel ferroelectric liquid-crystalline polymers with fast electro-optic switching times

The synthesis and ferroelectric properties of several novel liquid-crystalline polymers are presented. By manipulating the number of side-group mesogens attached to the polysiloxane backbone, it has been possible to achieve many significant properties: large range of the ferroelectric smectic C<SUP>∗</SUP> phase extending to sub-ambient temperatures, spontaneous polarization values up to 300 nC/cm<SUP>2</SUP> at the lowest temperatures, and bistable electro-optic switching times approaching 100 μs near the smectic C<SUP>∗</SUP>-smectic A transition temperature. These properties are attractive from the point of view of display applications

Integrated Starter Generator for 42-V Powernet Using Induction Machine and Direct Torque Control Technique

This paper describes an integrated starter generator (ISG) for automobile applications with 42-V powernet. This system is based on an induction machine which is directly mounted on the engine crankshaft and controlled using the technique of direct torque control (DTC). The suitability of the technique for ISG application is explained. The control structure of DTC for ISG application is described. Detailed experimental results from a 1.4-1 diesel engine are presented demonstrating the performance of the system during cranking as well as generation. The ISG also incorporates the feature of "on the fly start" during generation mode. Details of a low voltage high current power converter developed for this application are also given

Molecular structure and pretilt control of photodimerized-monolayers (PDML)

We have studied the alignment of nematic liquid crystals on photo-sensitive chemisorbed monolayers. Surface modification and a single UV exposure at normal incidence resulted in photo-dimerized monolayers. A uniform, planar alignment of liquid crystals is realized on these surfaces. Chemical modification of the photo-sensitive chromophores of the monolayer allow fine-tuning of the pretilt. For a given alignment layer, there is a good correlation between the value of the pretilt and the polar properties of the liquid crystal used. Furthermore, the value of the pretilt depends on the chemical functionality at the outermost portion of the photo-alignment layer

Langmuir films of liquid crystalline materials: the influence of molecular architecture on morphology and properties

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Comparing the conductivity of molecular wires with the scanning tunneling microscope

Current-voltage characteristics as measured by scanning tunneling microscopy for several different molecular backbones are presented. It is demonstrated that isolated oligo(phenylene ethynylene) molecules have the same measured conductance as oligo(phenylene ethynylene) molecules in a crystalline self-assembled monolayer. This result suggests that previous studies involving relatively large surface areas of self-assembled monolayers can be applied to molecular electronics devices employing small numbers of molecules. In addition, gap resistance measurements are used to rank the molecular conductance of oligo(phenylene ethynylene), oligo(phenylene vinylene), and dodecanedithiol. The observed trend for isolated molecules agrees with earlier large-scale measurements