ISSN:0267-8292    

DOI:10.1080/026782998207514

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The author looks back over a scientific career of almost 50 years spent mainly in research on liquid crystals (LCs) and carried out largely in University service and latterly for about five years in Industry. In this review, the development through its rapid escalation starting in the early 1970s and stemming from the development of applications for LCs in electro-optical displays, itself set on course by the author's own discovery of the first materials enabling the production twisted nematic displays. The author's other contributions widened into a general review of current trends and activities in the field, with some emphasis being placed on threats to fundamental research posed by diminished funding and the current pressures on researchers to engage heavily in short term, 'wealth creating' projects. of UK LC research is traced mainly of commercially viable, long life in the field are discussed and

ISSN:0267-8292    

DOI:10.1080/026782998207523

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

By creating and developing materials whose properties could be fully characterized, Professor George W. Gray has played a pivotal role in advancing our knowledge of liquid crystal states of matter. To honour him on his birthday, I briefly sketch some of my experimental results where the purity and stability of his cyanobiphenyl establishing new physical phenomena: the first re-entrant phenomenon in physics (1975, 1981) and the recent resolution of the nematic-smectic A transition order (1989, 1990). Even today, George Gray's liquid crystal materials are outstanding model systems for building physical intuition of generic non-linear, non-equilibrium problems, one of the most exciting frontiers of physics research today (1991, 1992, 1995). compounds played a crucial role in

ISSN:0267-8292    

DOI:10.1080/026782998207532

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

History is not always straightforward not a simple description including the grey levels is given of the history of the chemistry of liquid crystals. Daniel Vorlander had the biggest impact following the discovery of liquid crystals in the first part of the 20th century. George Gray dominates the second part of the 20th century. black and white picture. Therefore a

ISSN:0267-8292    

DOI:10.1080/026782998207541

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The molecules of living systems invariably exhibit both thermotropic and/or lyotropic liquid crystalline properties. In some cases the mesophases formed by bio-materials have lamellar structures, whereas in other situations they form columnar phases. Many liquid crystal biomaterials are found in cell membranes, indicating that such structures have properties that are dependent on liquid crystallinity for their behaviour of a variety of bio-materials is discussed. function. In this article the mesomorphic

ISSN:0267-8292    

DOI:10.1080/026782998207550

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A review is presented of some interesting structural properties of monomolecular layers at the air/water interface (Langmuir films) and of organized multilayer structures of organic molecules (Langmuir-Blodgett films). In particular multilayer films of bipolar lipids from archaebacteria and of proteins are considered, together with single-electron junction quantum effects in parallel, special emphasis is given to some recently developed experimental techniques based on X-ray scattering. supramolecular assemblies consisting of multilayers containing nanoparticles.

ISSN:0267-8292    

DOI:10.1080/026782998207569

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Systems far from thermodynamic equilibrium are discussed, e.g. lasers, amoeboid cells, cell clusters, etc. Different types of instabilities are described by rate equations. The ordered state is produced out of a uniform state and a self-organized machine is obtained. The spatialtemporal pattern of an interfacial instability can automobile (transporter). The temporal pattern makes the machine cycle while the spatial pattern produces the spatial spread machine. The directed by using light-sensitive molecules like spiropyran in the interface. The organization of amoeboid cells is discussed. The signal transduction chain of amoeboid migrating cells is approximated; the plasma membrane is the essential element. The membrane contains (i) a detection unit for registering extracellular signals and (ii) a chemical amplifier. The second intracellular signal created performs several functions: (i) the activation of the microfilaments, (ii) the activation of the adhesion proteins and (iii) the renewal of the detection unit. The processes are described by rate equations and the diffusion of the small sized molecules of the second intracellular signal are considered. The theoretical predictions are compared with experimental results: (i) an inactivated cellular state is predicted for low pumping; (ii) an isotropic state for higher pumping (cell adhesion but no migration); (iii) a polar activated cellular state for even higher pumping (adhesion and directed migration); (iv) a bipolar activated (cell elongation and orientation). The machine characteristics of the different activated states are discussed: (i) the monopole moment of the loaded receptors is the signal for the speed; (ii) the dipole moment of the receptor distribution in respect to the long axis of the cell is used as feedback signal in the automatic controller responsible for the angle of migration; (iii) the quadrupole moment of the receptor distribution is responsible for cell elongation and orientation. The model predictions are verified for different amoeboid cells, e.g. granulocytes, monocytes, melanocytes, fibroblasts, osteoblasts, neural crest cells, etc. Interacting cells have the ability to form ordered structures. A polar and predicted and actually verified. be used to build a fluid self-organized spatial movement of droplets can be the machine equation is extracted. Only cellular state for even higher pumping apolar nematic liquid crystal phase is

ISSN:0267-8292    

DOI:10.1080/026782998207578

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Conoscopic studies reveal that the nematic phase of 4,4-(p-terphenyl)-bis\[2,3,4-tri(dodecyloxy)benzal]imine is biaxial, the biaxial angle increasing with schlieren textures exhibited by the nematic phase have been between glass plates, as well as free-standing consisting entirely of s or 2-brush disclinations, confirming an earlier suggestion that the absence of 4-brush disclinations is evidence of biaxiality. decreasing temperature. The examined. Films sandwiched films, exhibit a nematic schlieren texture

ISSN:0267-8292    

DOI:10.1080/026782998207587

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Anisotropic networks, elastomers and gels exhibit piezoelectric, pyroelectric, ferroelectric and NLO properties of potential interest for use communication and processing technologies. The formation, properties and applications of such anisotropic, mainly liquid crystalline, networks are described. If some of the molecules in a liquid mixture contain at least two reactive groups which can be either photochemically or thermally polymerized, then crosslinked, anisotropic networks, elastomers and gels can be produced. Solid macroscopically aligned elastomers or networks can be formed as required beforehand or simultaneously by orientation of the sample. Anisotropic gels consist of a solid anisotropic network and non-covalently bonded, but strongly oriented domains of low molar mass liquid crystals. Anisotropic networks, elastomers preformed amorphous or liquid crystalline polymers incorporating additional reactive groups, which can be macroscopically oriented in the additional crosslinking reactions. Reversible networks, elastomers and gels can be prepared either non-covalently or covalently by thermally side group polymers and low molar mass molecules, liquid crystalline properties in the pure state. in many electro-optic devices for optical and gels can be prepared from liquid crystalline state and then fixed by reversible linkages between, for example, neither of which necessarily exhibit

ISSN:0267-8292    

DOI:10.1080/026782998207596

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In this paper the 'unconventional' optical non-linearities of liquid crystals are considered. The basic ideas for the interpretation of collective thermal origin are reviewed. After reporting the which are the major challenges for scentists in this field are recalled. reorientation and of other phenomena of main results of this approach, the issues

ISSN:0267-8292    

DOI:10.1080/026782998207604

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor