The formation of threads in the dynamic scattering mode of nematic liquid crystals

Nehring, J.; Petty, M.S.

doi:10.1016/0375-9601(72)90584-1

Cited by 14 publications

(2 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These disclinations are clearly visible for the LC 440 (Fig. 15a, b) and as will be demonstrated they play a considerable part in the dynamic scatteringan idea developed by De Gennes [42] and experimentally observed by J. Nehring and M. Petty [43] and by M. Bertolotti's Group [44]. It is difficult to observe the disclinations without the high frequency electric field due to their overlapping with the focal lines brought about by the Z deformation, also due to the hydrodynamics (compare Figs.…”

supporting

confidence: 63%

Parallel and cross-like domains due to d.c. and low frequency (< 2 Hz) electric fields in nematic liquid crystal layers with negative dielectric anisotropy

Hinov

Vistin

1979

J. Phys. France

View full text Add to dashboard Cite

2014 On étudie les domaines parallèles et croisés obtenus par application de champs électriques continus et basse fréquence ( 2 Hz) sur des cristaux liquides MBBA et 440 à anisotropie de susceptibilité diélectrique négative. Les principaux résultats sont : 2014 la reproductibilité des domaines parallèles particulièrement pour des couches inclinées d'épaisseur 5-90 03BCm avec un ancrage faible assuré par un agent tensio-actif (savon) ; 2014 la création de domaines en croix dans des couches minces homéotropes ; ces domaines apparaissent dans la région de la cathode et sont dus au fort champ inhomogène générateur de structures flexion-éventail séparées par des disclinaisons.Parmi les mécanismes électrostatiques et électrodynamiques connus, seul l'effet flexoélectrique dû à un gradient de champ électrique peut expliquer la formation de ces domaines.

show abstract

supporting

confidence: 63%

Parallel and cross-like domains due to d.c. and low frequency (< 2 Hz) electric fields in nematic liquid crystal layers with negative dielectric anisotropy

Hinov

Vistin

1979

J. Phys. France

View full text Add to dashboard Cite

show abstract

“…Sequences of phytoplanktonic taxa, such as green algae and diatoms (14), are from organisms that require solar radiation for active photosynthesis and are, therefore, not suited to this aphotic environment. Other sequences may represent dead or encysted forms; for example, dinoflagellate cysts have been detected in marine sediments (15). Some sequences (A2 E003, A2 E011, A3 E002, C1 E024, A1 E004, C1 E001, and C1 E027) were more frequently recovered (nearly identical sequences from Ն10 clones) from our libraries.…”

Section: Resultsmentioning

confidence: 91%

Benthic eukaryotic diversity in the Guaymas Basin hydrothermal vent environment

Edgcomb

Kysela

Teske

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

345

337

View full text Add to dashboard Cite

Molecular microbial ecology studies have revealed remarkable prokaryotic diversity in extreme hydrothermal marine environments. There are no comparable reports of culture-independent surveys of eukaryotic life in warm, anoxic marine sediments. By using sequence comparisons of PCR-amplified small subunit ribosomal RNAs, we characterized eukaryotic diversity in hydrothermal vent environments of Guaymas Basin in the Gulf of California. Many sequences from these anoxic sediments and the overlaying seawater represent previously uncharacterized protists, including early branching eukaryotic lineages or extended diversity within described taxa. At least two mechanisms, with overlapping consequences, account for the eukaryotic community structure of this environment. The adaptation to anoxic environments is evidenced by specific affinity of environmental sequences to aerotolerant anaerobic species in molecular trees. This pattern is superimposed against a background of widely distributed aerophilic and aerotolerant protists, some of which may migrate into and survive in the sediment whereas others (e.g., phototrophs) are simply deposited by sedimentary processes. In contrast, bacterial populations in these sediments are primarily characteristic of anoxic, reduced, hydrocarbon-rich sedimentary habitats. P hylogenetic studies of ribosomal RNAs from cultured species imply that large evolutionary distances separate major groups of protists. Certain aerotolerant anaerobic parasites seem to represent early diverging lineages in the eukaryotic line of descent (1). Because they do not require atmospheric levels of oxygen for growth, these organisms lack mitochondria and peroxisomes. The absence of these features in the most divergent eukaryotic lineages and the thermophilic phenotype of the deepest prokaryotic branches suggest that warm, anoxic environments surrounding deep-sea hydrothermal vents might support novel and diverse eukaryotic communities. Little information about the phenotypic and evolutionary diversity of free-living protists from anoxic marine environments is available. Most studies of protist diversity rely upon morphological characters to differentiate between genera. However, culturebased studies and microscopical criteria cannot provide quantitative measures of genetic diversity. More significantly, these methods frequently do not provide comprehensive profiles of community composition. Cultivation-independent molecular surveys of eukaryotic microbial diversity based on comparisons of PCR amplicons of small subunit (SSU) rRNA genes from marine pelagic environments reveal a microbial world with few taxonomically assignable protists (2, 3). There are no analogous molecular surveys of eukaryotic microbial diversity in anoxic, deep-sea sediments.Here, we report the results of a molecular survey of eukaryotic community SSU rRNA gene composition in sediments and the seawater interface proximal to a deep-sea hydrothermal vent. The study site is Guaymas Basin, Gulf of California, which is a hydrothermally active env...

show abstract

Liquid-crystal displays, LCD

Channin¹,

Sussman²

1980

Display Devices

View full text Add to dashboard Cite

Liquid-crystal displays (LCDs) are light-controlling devices, as opposed to light-emitting displays such as cathode-ray tubes, light-emitting diodes, and plasma displays. They rely on the optical properties of liquid-crystal materials to control the transmission of light from an external source, be it ambient illumination or lighting provided as a part of the display. There are several kinds of liquid-crystal materials that have been used in displays and a multitude of configurations for constructing addressing, and optically presenting information using these materials. This chapter will attempt to survey this diversity of technology, but will concentrate on the configurations most used at present or that have particular promise of future applications. Background InformationAll liquid-crystal displays consist of a thin layer of liquid-crystal material together with means for changing the optical properties of the layer in accordance with the information to be displayed. Liquid crystals are organic materials that possess an intermediate phase, or mesophase, between the solid and isotropic liquid phases. In the liquid-crystalline phase, they have the ability to flow and conform to their surroundings as do ordinary liquids, but the molecules of liquid crystals interact with each other to produce various kinds of ordered states. The simplest of these is the nematic phase, in which the molecules tend to have their major axes parallel to each other. The cholesteric phase has a helicical structure of molecular ordering, and the smectic phases show various kinds of layered structures with the long molecular axes parallel to each other within each layer. (The properties of these phases have been reviewed in several recent books and articles [4.1-4].)With proper treatment of the surfaces bounding the liquid-crystal layer, the ordering can be made uniform throughout the entire layer. Because the materials are liquids, relatively little external energy need be applied to produce large changes in the molecular ordering. In addition, since the liquid crystals are anisotropic, these changes can be used to produce visible optical effects through polarization rotation, light scattering, or pleochroic light absorption.Conveniently, the simplest type of liquid crystal has also turned out to be the most useful for display applications. All the devices currently marketed use

show abstract

The formation of threads in the dynamic scattering mode of nematic liquid crystals

Cited by 14 publications

References 5 publications

Parallel and cross-like domains due to d.c. and low frequency (< 2 Hz) electric fields in nematic liquid crystal layers with negative dielectric anisotropy

Parallel and cross-like domains due to d.c. and low frequency (< 2 Hz) electric fields in nematic liquid crystal layers with negative dielectric anisotropy

Benthic eukaryotic diversity in the Guaymas Basin hydrothermal vent environment

Liquid-crystal displays, LCD

Contact Info

Product

Resources

About