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The EAST plasmas heated with deuterium neutral beam injection and ion cyclotron resonance heating (ICRH) have been simulated by the TRANSP code. The analysis has been conducted using the full wave solver TORIC5, the radio frequency (RF)-kick operator, and NUBEAM to model the RF heating effects on fast ion velocity distribution. In this work, we present several simulated results compared with experiments for high power EAST scenarios, indicating that the interactions between ICRH and fast ions can significantly accelerate fast ions, which are confirmed by the increased neutron yield and broadened neutron emission spectrum measurements.

Neutron emission spectroscopy and neutron yield measurements are important for high neutral beam injection (NBI) power heating at the Experimental Advanced Superconducting Tokamak (EAST). The neutron yields mainly depend on the deposition from NBI to the deuterium plasmas in the EAST. We have recently used TRANSP with time dependent diagnostic results to simulate the transport process of 30s long pulse deuterium plasma discharges in the EAST, obtaining the time dependent fast ion distribution, neutron emission spectrum, and total neutron emission rate. Combined with the time trace of the result measured by a standard 235U fission chamber, the effects of different configurations of NBI heating in EAST fusion plasmas have been evaluated.

Over 99% of human rabies cases in endemic areas are transmitted by dogs. Without the elimination of dog rabies, it is not easy to reduce human rabies infection. Controlling dog rabies, especially in ownerless or free-roaming dogs, is critical if we are to decrease the rate of human rabies infection. There are several components in a strategy to eliminate dog-mediated rabies in Asia. Each government must make sure that rabies is either a reportable disease or a notifiable disease and enforce the reporting requirements accordingly. They must also focus on organising and operating special rabies control committees that work with relevant agencies under the 'One Health' banner. They should also implement a national rabies control programme that includes mass dog vaccination, laboratory-based surveillance, stable budget allocation, a rapidreporting system, management of dog populations, international cooperation, prevention of animal introductions from other countries, and risk assessment to analyse the programme's weaknesses. As several developed countries have shown, an effective rabies control strategy leads to rabies-free status. In the Republic of Korea, human rabies has not occurred since 2004, and there have not been any confirmed cases of dog rabies or cases of rabies in wild animals, including raccoon dogs, since 2014. The successful implementation of the key strategies used to eliminate rabies in the Republic of Korea will enable other Asian countries to eliminate dog-mediated human rabies.Plus de 99 % des cas humains de rage survenant dans les zones où cette maladie est endémique sont dus à des morsures de chiens. Il paraît difficile de réduire le nombre d’êtres humains infectés par le virus de la rage sans éliminer la rage canine. Le contrôle de la rage canine, en particulier dans les populations de chiens sans propriétaire ou errants est une condition essentielle si nous voulons faire baisser l’incidence de la rage humaine. La stratégie d’élimination de la rage transmise par les chiens en Asie comporte plusieurs composantes. Les gouvernements doivent s’assurer que la rage est une maladie à déclaration ou notification obligatoires et que les dispositions prévues en matière de déclaration sont bien appliquées. Ils doivent également axer leurs efforts sur la mise en place et le bon fonctionnement de commissions compétentes en matière de lutte contre la rage, qui opéreront en collaboration avec les agences pertinentes sous la bannière « Une seule santé ». En outre, chaque pays mettra en oeuvre un programme national de lutte contre la rage en intégrant toutes ses composantes : vaccination des chiens, surveillance sérologique, enveloppe budgétaire stable, système de notification accélérée, gestion des populations de chiens, coopération internationale, prévention de l’introduction d’animaux à partir d’autres pays et enfin évaluation des risques en vue d’analyser les faiblesses du programme. Ainsi que l’ont montré plusieurs pays développés, les stratégies efficaces de lutte contre la rage permettent d’atteindre le statut indemne de rage. En république de Corée, aucun cas de rage n’a été signalé chez l’homme depuis 2004 ; de même, aucun cas de rage n’a été confirmé chez le chien ni dans la faune sauvage, y compris chez le chien viverrin, depuis 2014. L’exemple des stratégies d’élimination de la rage appliquées avec succès en république de Corée permettra à d’autres pays asiatiques de venir à bout de la rage humaine transmise par le chien.Los perros son los transmisores de más del 99% de los casos de rabia humana que se dan en las zonas de endemismo. De ahí la dificultad de reducir el número de personas infectadas si no se logra previamente eliminar la enfermedad en el perro, o dicho de otro modo: el control de la rabia canina, sobre todo en los perros vagabundos o sin dueño, es esencial para lograr menores índices de infección humana. Una estrategia encaminada a eliminar la rabia transmitida por perros en Asia ha de tener varios componentes. Todos los gobiernos deben hacer de la rabia una enfermedad de notificación obligatoria y hacer aplicar en consecuencia las reglas al respecto. También deben privilegiar la creación y el funcionamiento de comités especiales de lucha antirrábica que trabajen con los organismos competentes desde la lógica y los postulados de «Una sola salud». Además, deben instituir un programa nacional de lucha contra la rabia que, además de la vacunación masiva de perros, incluya planes de vigilancia en laboratorio, una partida presupuestaria estable, un sistema de notificación rápida, la gestión de las poblaciones caninas, la cooperación internacional, la prevención de la introducción de animales desde otros países y un proceso de determinación del riesgo para analizar los puntos débiles del programa. Como ha quedado patente en varios países desarrollados, una estrategia eficaz de lucha antirrábica acaba conduciendo a la condición de país libre de la enfermedad. En la República de Corea no se han producido casos de rabia humana desde 2004, y no ha habido ningún caso confirmado de rabia canina ni de rabia en animales silvestres, perros mapaches inclusive, desde 2014. La eficaz aplicación de las estrategias fundamentales empleadas en la República de Corea para eliminar la enfermedad hará posible que otros países asiáticos logren eliminar la rabia humana transmitida por perros.

Stilbene crystal detectors are widely used as fast neutron measurement tools based on recoil proton detection, such as liquid scintillators. A compact stilbene crystal neutron spectrometer (CSCNS) has been installed at the Experimental Advanced Superconducting Tokamak (EAST) to obtain information on fuel ions produced in the plasma core because of its merits of good n/γ discrimination capability, high detection efficiency, and fast response. For the first time, CSCNS has been used for neutron emission spectroscopy measurements in EAST plasmas with neutral beam injection (NBI) heating. The CSCNS has the same horizontal line of sight as the time-of-flight enhanced diagnostics neutron spectrometer. Under NBI heating scenarios, the time trace of the neutron yield monitored by the CSCNS is similar to the one monitored by a standard 235U fission chamber. The experimental pulse height spectra are also similar to the simulated ones generated by folding the simulated neutron energy spectrum with the detector response functions. These results demonstrate the capability of the CSCNS for neutron diagnostics and the study of fast-ion physics in EAST.

Inflammatory mediators, such as cytokines, chemokines and arachidonic acid compounds, lead to vascular permeability and dilation and increase sensitization and pain receptors. Proinflammatory cytokines, including tumor necrosis factor, are involved in the etiology of clinical neurological disorders. These cytokines activate nuclear factor-κB (NF-κB) which leads to the activation of different inflammatory genes. TNF implicated in neurological disorders has an important role in the activation of microglia and astrocytes. The inhibition of TNF may lead to the decrease of microglia activation and can be useful for therapeutic intervention. TNF, at the site of nerve injury may activate mast cells (MCs) which mediate pathologic events such as headache and pain. TNF is the only cytokine stored in mast cells and can be rapidly released along with biogenic amines after MC stimulation. Activation of MCs leads to NF-κB and AP1 generation with release of many cytokines including TNF, IL-33 and IL-1. In this paper we discuss the role of TNF in MC activation, mediating pain and neurological disorders.

The threat of climate change and global warming is now recognised worldwide and some alarming manifestations of change have occurred. The Asian continent, because of its size and diversity, may be affected significantly by the consequences of climate change, and its new status as a 'hub' of livestock production gives it an important role in mitigating possible impacts of climate variability on animal health. Animal health may be affected by climate change in four ways: heat-related diseases and stress, extreme weather events, adaptation of animal production systems to new environments, and emergence or re-emergence of infectious diseases, especially vector-borne diseases critically dependent on environmental and climatic conditions. To face these new menaces, the need for strong and efficient Veterinary Services is irrefutable, combined with good coordination of public health services, as many emerging human diseases are zoonoses. Asian developing countries have acute weaknesses in their Veterinary Services, which jeopardises the global surveillance network essential for early detection of hazards. Indeed, international cooperation within and outside Asia is vital to mitigating the risks of climate change to animal health in Asia.

The sintering and dissolution process was used to produce open cell Al/Al2O3 composite foams with a relative density of 0·25–0·40 and a pore size of 112–400 μm. The compressive properties of as fabricated and T6 heat treated Al/Al2O3 composite foams were investigated. After T6 heat treatment, the yield strength of the open cell Al/Al2O3 composite foams is increased relative to the untreated material. T6 heat treatment gives rise to a mean 36% increase in the compression yield strength of the open cell Al/Al2O3 composite foams. The yield strength of as fabricated and T6 heat treated Al/Al2O3 composite foams shows a significant dependence on the relative density and also exhibits a distinct dependence on the pore size. After T6 heat treatment, the influence of the relative density and pore size on the compressive behaviour of Al/Al2O3 composite foams becomes more distinct.

Nanoconfined polymer chains—as can be formed when polymers intercalate into layered inorganic materials—show remarkable bulk properties, many of which are connected to dynamical heterogeneity in the polymeric phase. Microscopically, it appears that slow dynamical modes are associated with the species in direct contact with the surface, with substantially more mobile species only a fraction of a nm away. In the more distant phase, larger angle and moderately fast dynamics (typically, ns– μ s ) grows in over a broad temperature range not well correlated to bulk phase transitions. In this work, we probe the slowest dynamical modes and apply one- and two-dimensional 2H exchange NMR experiments to study thin polymer layers intercalated between the flat inorganic faces of fluorohectorite (FH). One sample is created by intercalation of perdeuterated poly(ethylene oxide) into FH, and the second by intercalation of d 3 -poly(styrene) into a surface-modified FH. Large-amplitude reorientation of the PEO backbone is substantially hindered in the narrow two-dimensional layers, and reorientation is limited to small-amplitude steps at rates that are largely independent of temperature. Simulations of the two-dimensional exchange experiments suggest that dynamics in nanoconfined polymers is associated with small-angle rotational diffusion.

Objective – To identify various subtypes of spinocerebellar ataxias (SCAs) among autosomal dominant cerebellar ataxia (ADCA) patients referred to our research center, SCA1, SCA2, SCA3/MJD (Machado–Joseph disease), SCA6, SCA7, SCA8 and SCA12 loci were assessed for expansion of trinucleotide repeats. Patients and methods – A total of 211 ADCA patients, including 202 patients with dominantly inherited ataxia from 81 Taiwanese families and nine patients with sporadic ataxia, were included in this study and subjected to polymerase chain reaction (PCR) analysis. The amplified products of all loci were analyzed on both 3% agarose gels and 6% denaturing urea-polyacrylamide gels. PCR-based Southern blots were also applied for the detection of SCA7 locus. Results – The SCA1 mutation was detected in six affected individuals from one family (1.2%) with expanded alleles of 50–53 CAG repeats. Fourteen individuals from nine families (11%) had a CAG trinucleotide repeat expansion at the SCA2 locus, while affected SCA2 alleles have 34–49 CAG repeats. The SCA3/MJD CAG trinucleotide repeat expansion in 60 affected individuals from 26 families (32%) was expanded to 71–85 CAG repeats. As for the SCA7 locus, there were two affected individuals from one family (1.2%) possessed 41 and 100 CAG repeats, respectively. However, we did not detect expansion in the SCA6, SCA8 and SCA12 loci in any patient. Conclusions – The SCA3/MJD CAG expansion was the most frequent mutation among the SCA patients. The relative prevalence of SCA3/MJD in Taiwan was higher than that of SCA2, SCA1 and SCA7.

To understand chirality in cholesteric (Ch) liquid crystals, we performed an experimental study on the Ch-smetic A (SmA) transition of a cholesteric liquid crystal. By studying the reflection spectrum at zero field and at the critical electric field used to unwind the helical structure, we were able to measure the helical pitch P and the twist elastic constant K 22 in the Ch phase. As the temperature was lowered toward the Ch-TGB phase transition, the helical pitch and twist elastic constant diverged. The results support the model that short range SmA forms in the Ch phase. When the results were fitted by power-law temperature dependence, the exponent for P was 0.78 and the exponent for K 22 was 1.36.

Molecular Dynamics (MD) simulations are used to explore the structure and dynamics of polystyrene confined in 2 nm slit pores, between parallel, crystalline, mica-type surfaces. The systems simulated resemble experimentally studied intercalated nanocomposites, where polystyrene is inserted between layered-silicate layers. The molecular modeling perspective complements the experimental findings and provides insight into the nature of polymers in nanoscopic confinements, especially into the molecular origins of their macroscopic behavior. Namely, a comparison between simulation and NMR studies shows a coexistence of extremely faster and much slower segmental motions than the ones found in the corresponding bulk polymer at the same temperature. The origins of these dynamical inhomogeneities are traced to the confinement induced density modulations inside the 2 nm slits. Fast relaxing phenyl and backbone moieties are found in low density regions across the film, and preferentially in the center, whereas slow relaxing moieties are concentrated in denser regions in the immediate vicinity of the confining surfaces. At the same time, the temperature dependence of the segmental relaxations suggests that the glass transition is suppressed inside the confined films, an observation confirmed by scanning calorimetry. © 2001 Elsevier Science B.V. All rights reserved.

Fluids in nanoscopic confinements possess a variety of unusual properties, and in particular, remarkable dynamical heterogeneities which vary on length scales as short as a fraction of a nanometer. While the surface forces apparatus provides an experimental probe of macroscopic properties of fluids in contact with atomically smooth solid surfaces, few experimental probes are available which test the microscopic origins of these heterogeneities. In this article we describe our recent efforts to apply nuclear magnetic resonance spectroscopy to nanoscopically confined poly(styrene) (PS) created by intercalation into a surface-modified fluorohectorite. A comparison between surface-sensitive cross polarization experiments with spin–echo experiments which probe the entire organic layer suggests that PS in the center of the nanopores is more mobile than the bulk at comparable temperatures, while chain segments which interact with the surface are dynamically inhibited.

Characterization of dynamics of the charge-carrying species in polymer electrolytes has proven difficult. In this work we focus on a nanocomposite polymer electrolyte created when poly(ethylene oxide) (PEO) is intercalated into a layered silicate, Li–montmorillonite. We characterize both the Li+–silicate distance and the cation dynamics by analysis of the changes in 7Li nuclear magnetic resonance (NMR) line shape observed as the temperature is changed and cation diffusion is enabled. The observed spectra are compared to spectral simulations which emphasize the role of dipolar fields, associated with the static paramagnetic Fe3+ ions randomly distributed at the Al3+ lattice sites, interacting with the mobile cations. Low temperature line shapes are asymmetric, and not simply related to line shapes of more typical NMR interactions. Simulation of 7Li NMR spectra and comparison to experimental spectra shows that the Li+ interacts most strongly with the silicate surface layer, and all our evidence indicates th...

The sintering and dissolution process (SDP) was used to produce the fine open cell Al–Al2O3 composite and pure Al foams with the relative density of 0·25–0·40 and the pore size of 112–400 μm. The composite foam exhibited much higher yield strength and Young's modulus than the pure Al foam, and thus had an elevated plateau stress. Moreover, the composite foam showed a unique dependence of the compression stress on the pore size, i.e. it increased with increasing pore size, which was quite different from that for the common metal foams.

The grayish–black ternary nitride LixMn2−xN (x≈0.67) was prepared from lithium nitride, manganese powder and nitrogen. The phase adopts an anti-Rutile structural arrangement with lithium and manganese atoms disordered on one site: Space group P42/mnm (No. 136), a=4.68578(9) A, c=2.97762(9) A, Z=2. The electrical resistivity of a sintered pellet (ρ≈8.5·10−3 Ω cm at 250 K) increases slowly as the temperature is decreased (to about 1·10−2 Ω cm at 4 K). Magnetic susceptibility and solid state 6Li-NMR measurements suggest localized magnetic moments on the manganese atoms and probably an antiferromagnetic ordering at about 115 K.

We have measured both of the electrooptical and the Raman characteristics of polymer - stabilized cholesteric texture(PSCT) films fabricated with various polymer concentrations. Some correlations between these two characteristics were found. This indicates the Raman experiment could provide us another technique to analyze the PSCT films.

In this paper, airborne experiments of sea surface altimetry using reflected Global Positioning System (GPS) signals is presented. The processing of reflected GPS signal is concerned in detail and a new method of noncoherent summation, which can align coherent correlation outputs of the sea surface reflected GPS signals, is proposed. Results show that relative delay estimation of meter level precision can be obtained in one second, and the sea surface height error is expected to be at the same order of magnitude.

The grayish–black ternary nitride LixMn2−xN (x≈0.67) was prepared from lithium nitride, manganese powder and nitrogen. The phase adopts an anti-Rutile structural arrangement with lithium and manganese atoms disordered on one site: Space group P42/mnm (No. 136), a=4.68578(9) A, c=2.97762(9) A, Z=2. The electrical resistivity of a sintered pellet (ρ≈8.5·10−3 Ω cm at 250 K) increases slowly as the temperature is decreased (to about 1·10−2 Ω cm at 4 K). Magnetic susceptibility and solid state 6Li-NMR measurements suggest localized magnetic moments on the manganese atoms and probably an antiferromagnetic ordering at about 115 K.

Hypersensitivity pneumonitis (HP) can be caused by drugs administered via routes other than the airway. We report a case of HP caused by intravesical bacille Calmette-Guerin (BCG) administered for the treatment of bladder cancer. We attempt to identify the causative agents of HP. A 60-year-old, nonsmoking homemaker was referred to our hospital with nonresolving pneumonia. The patient had dyspnea, cough, and fever that started after 3 weekly cycles of intravesical BCG. High-resolution computed tomography of the chest revealed multiple tiny nodules and ground-glass opacities on both lung fields. Pulmonary function tests revealed a restrictive ventilatory defect with decreased diffusion capacity. Histopathology of the transbronchial lung biopsy specimens showed immature noncaseating granulomata. Immunoblotting analysis of serum and BCG demonstrated more than 10 immunoglobulin G fractions binding to BCG. This case illustrates that HP can be caused by intravesical instillation of BCG.

Anticonvulsant hypersensitivity syndrome (AHS) is a multisystemic disorder involving cutaneous changes and typical blood abnormalities that can be triggered by aromatic anticonvulsant drugs.The syndrome is commonly associated with a macular or papular rash or erythroderma. Acute generalized exanthematous pustulosis is a very rare cutaneous manifestation of AHS. A 41-year-old man was referred to our hospital for evaluation of a 3-day history of fever, leukocytosis, and generalized skin eruption. The patient had been taking carbamazepine for 1 month to treat hand tremor following surgery for intracerebral hemorrhage. Physical examination revealed facial edema and a large number of variable-sized pustules covering the body. Initial laboratory testing showed peripheral blood eosinophilia and abnormal liver function.A biopsy of pustular lesions revealed intraepidermal pustules, with perivascular lymphocytic infiltration. The skin lesions and laboratory results improved after withdrawal of carbamazepine and treatment with oral corticosteroids.

The threat of climate change and global warming is now recognised worldwide and some alarming manifestations of change have occurred. The Asian continent, because of its size and diversity, may be affected significantly by the consequences of climate change, and its new status as a 'hub' of livestock production gives it an important role in mitigating possible impacts of climate variability on animal health. Animal health may be affected by climate change in four ways: heat-related diseases and stress, extreme weather events, adaptation of animal production systems to new environments, and emergence or re-emergence of infectious diseases, especially vector-borne diseases critically dependent on environmental and climatic conditions. To face these new menaces, the need for strong and efficient Veterinary Services is irrefutable, combined with good coordination of public health services, as many emerging human diseases are zoonoses. Asian developing countries have acute weaknesses in their Veterinary Services, which jeopardises the global surveillance network essential for early detection of hazards. Indeed, international cooperation within and outside Asia is vital to mitigating the risks of climate change to animal health in Asia.

In order to further understand the structure of the blue phase III (BPIII) phase of chiral liquid crystals, we have observed the effect of electric fields on the reflectivity of BPIII phases in which the liquid crystal has negative dielectric anisotropy. The reflectivity increases dramatically with increasing field, in contrast to the behaviour for materials of positive dielectric anisotropy. We compare the data with cubic domain and double-twist models for BPIII structure and we find that the data best agree with the double-twist model and possibly with an O5 cubic domain model.

A high-temperature liquid chromatographic technique is employed for the separation of commercially available polymer additives to enhance the resolution and speed. Separation efficiencies and elution behaviors for seven phthalate plasticizers and five antioxidants are evaluated at elevated column temperatures and with a thermal gradient. Diamondbond C18 (octadecylsilica), Zirchrom PS (zirconia-based polystyrene), and Zirchrom PBD (zirconia-based polybutadiene) columns are selected for the study because of their thermal stability. The temperature programming is controlled with a column oven in conjunction with an independent mobile phase preheater and a post-column effluent cooling assembly. Van't Hoff plots show that the reverse-phase liquid chromatography mechanism is maintained over a wide range of column temperatures. A 1% increase of acetonitrile in the mobile phase is estimated to have a comparable effect as a 7-7.5 degrees C column temperature increase on the retention time changes.

A novel liquid crystal/polymer gel dispersion is reported which exhibits two contrasting optical states which are stable at zero field; one state reflects light at a preselected color and the other state is scattering. In a display cell, the material can be selectively driven to either state by a suitable voltage pulse. A polymer gel can be used to stabilize the optical states of a cholesteric liquid crystal to create a bistable color display. This system has a high potential for multiplexed flat panel displays without the use of an active matrix substrate. Such a display can also be used for long-term information storage and optical signal processing. >

A novel cholesteric liquid crystal/polymer gel dispersion has been constructed which can be operated either in normal mode or reverse mode. The normal-mode cell is opaque in a field-OFF condition and clear in a field-ON condition. The reverse-mode cell is clear in a field-OFF condition and opaque in a field-ON condition. In the clear state, both cells are haze-free for all viewing angles. The cholesteric liquid crystal/polymer gel dispersion can be used to make normal-mode and reverse-mode light shutters. The reverse-mode shutter has very good electrooptical characteristics, exhibiting a sharp transition, small hysteresis, and fast dynamic response. >

We describe a new type of color display consisting of polymer‐dispersed droplets of chiralliquid crystal having negative dielectricanisotropy. In the field‐off state, the dropletsscatter light randomly. In the field‐on state the droplets selectively reflect a bright color. Measurements of reflectivities and switching times are presented and we discuss possible applications.

Noise spectroscopy has previously been demonstrated to provide broad-bandwidth excitation with minimal applied RF field strengths. Nonetheless, its application to broadline solid-state NMR spectroscopy has appeared limited by the need to have unrealistically short probe- and receiver-recovery times after pulses. In this Communication, we explain theoretically and demonstrate experimentally that accurate lineshapes can be observed in 2 H solid-state NMR spectroscopy even where the probe ringdown time greatly exceeds the required time between sampled data points. Moreover, accurate lineshapes can be observed to ±125 kHz using RF fields as weak as a few hundred hertz.

We used simplified Mueller matrix (3×3) method to study the optics of reflective twisted nematic (BTN) displays. We obtained a general analytical solution, which shows how to choose display parameters to achieve high contrast ratio between the two stable states. Our results show that the employment of compensation films provides much more freedom to improve electro-optic properties such as response time, viewing angle dependence and contrast.

We have designed a novel trans-reflective liquid crystal display that utilizes a dielectric mirror and electric controlled birefringence ECB effect of a liquid crystal cell. The visible spectrum is divided into two regions with the transmissive mode operated in short wavelength region and the reflective mode operated in long wavelength region. The display has the advantages: 1 the brightness as a function of applied voltage is the same for both modes, 2 it does not need absorption films such that there is no light loss for the backlight.

We have developed a polymer dispersed cholesteric liquid crystal which exhibits two stable states at zero field: reflecting planar texture and non-reflective focal conic texture. Both states have thresholds under driving voltage pulses. The material can be used to make multiplexed displays on passive matrix. Because the liquid crystal is encapsulated, the dispersion can be coated on plastic substrates to make large size displays. Furthermore, it can be used to make single layer full color displays by using a photo-tuning method.

We analyzed the light emission from a backlight system with a cholesteric broad band polarizer by using Berrman 4×4 method. We found that light intensity in directions with polar angle smaller than 30°o was increased and higher than the back light system with only a linear polarizer. We also designed a light recycling backlight system and calculated the light efficiency.

We have developed two types of polymer stabilized cholesteric dichroic dye displays. In the first type, an anisotropic polymer network perpendicular to the cell surface was formed by photo-polymerization in the homeotropic texture in the presence of an electric field. The polymer network enhanced the hysteresis of the voltage-transmittance curve, and the material can be operated in bistable mode at a bias voltage in the hysteresis loop. In the second type, a random polymer network was formed by photo-polymerization in the isotropic phase at an elevated temperature. The polymer network suppressed the hysteresis, and the material can be operated in gray scale mode. The displays had high on-state transmittance, good contrast ratios, and were suitable for direct view display applications.

We report the first gray scale reflective bistable cholesteric display with dynamic drive. We successfully achieve 8 to 16 levels of gray on a VGA format display at 133 dpi. The image shows good contrast and rich gray depth.

The parameters of the 3-phase dynamic drive scheme depend on the transitions among cholesteric textures, which themselves are strongly temperature dependent. Temperature compensation must be made in order for the drive scheme to work in a wide temperature region. We have developed a compensation method in which the frequency of the driver clock is the only parameter that is required to be adjusted with temperature. Using this simple method, we have achieved consistently high contrast ratio of the display in a wide temperature region.

We have designed drive schemes which can update gradually the content of a bistable reflective cholesteric display. These scheme make use of the “kicking” effect as in addressing STN displays. The cholesteric material is kicked from the planar texture to the focal conic texture step-by-step or vice versa. We have also developed a new cholesteric display cell structure which has a 2 ms homeotropic-planar transition time. Using the new cell structure and the new drive scheme, we have achieved an addressing speed of 0.5 ms/line; the cholesteric display can be operated at a quasi-video rate.

Sorption isotherms and diffusion coefficients of water in a 0.3-mil Kapton polyimide film at 30, 45, and 60°C are reported. The data are well described by the dual mode sorption and transport models at low activities. At high penetrant activities, clustering of water is suggested by a Zimm–Lundberg analysis of the sorption data and the fact that the diffusion coefficient for water decreases with increasing external vapor activity. The effect of temperature on the diffusion coefficients at infinite dilution and the dual mode sorption parameters kD, b, and C are presented and discussed. The magnitude of the activation energy of the diffusion coefficient at infinite dilution, 5.4 kcal/mol, is smaller than the corresponding activation energy in more flexible chain polymers, perhaps suggesting that rather small backbone motions are associated with diffusion of water through the Kapton matrix. The predictions for the isosteric enthalpy of sorption from the dual mode model are presented and compared with the values determined from graphical analysis of the sorption isotherms performed independently without reference to the dual mode sorption model.

We have performed the first measurements on surface-aligned samples of the blue phase III of chiral liquid crystals and have tested proposed icosahedral, cubic-domain, and double-twist structures for blue phase III. Angular-reflection studies on surface-aligned samples show no evidence of expected icosahedral structure; uv reflection measurements on unaligned samples show no evidence of expected cubic-domain structure; and attempts to observe Cano fringes show no evidence for any spatial periodicity.

We have investigated the rheological properties of the Celanese copolyester with the composition 75 mol% p-hydroxybenzoic acid and 25 mol% 2-hydroxy-6-naphthoic acid (designated as 75HBA/25HNA). Three different samples having inherent viscosities 3.0, 6.0, and 9.2 dL/g were studied. A flow instability is observed at low shear stress which produces an irregularity in the fiber diameter. The surface irregularity becomes less pronounced above a minimum shear stress, indicating that the flow instability originates in the capillary. For these nematic melts, the minimum shear stress marking the onset of more regular flow is found to decrease with increasing temperature and with decreasing inherent viscosity of the copolyester. The die swell ratio of extrudates decreases with increasing shear stress. Fibers were spun from the samples having ηinh = 9.2 and 3.0 dL/g. The initial modulus and tenacity to break for 75HBA/25HNA fibers spun at sufficiently high shear stress to produce smooth filaments are significantly lower than the values we previously reported for fibers of the 58HBA/42HNA copolyester. Moreover, the optimum properties are obtained at relatively low spin-draw ratios. The 75HBA/25HNA polyester also exhibits a yield stress which decreases with increasing temperature. This observation indicates the presence of crystallities at the test temperatures. We believe that the higher content of HBA in the present copolymer gives rise to crystallization of HBA blocks in the thread line and that defects are introduced at higher spin-draw ratios which cause the mechanical properties to become worse.

The synthesis of (L)-(-)-4″-(2-methylbutylphenyl) 4″-(2-methylbutyl)-4-biphenylcar-boxylate (CE2) and related chiral liquid crystals has been discussed by Gray and McDonnell. We present here the first synthesis of the enantiomer of CE2 and we use it to measure the temperature-chirality phase diagram of the biue phases of CE2. This diagram is compared with that obtained using the CE2 “racemate” containing nonen-antiomeric optical isomers of CE2. The synthesis of (R)-(+)-2-methylbutan-l-ol which has been developed will be broadly useful for the preparation of other chiral liquid crystals having optically active (R)-2-methylbutyl sidechains.

A comparison of water sorption and diffusion behavior in 2 mil, as-received, Kapton1 film, and in otherwise identical but hygrothermally aged samples, suggests chemical differences between the samples. These differences can be related to known polyimide chemistry and the specific history encountered by the samples. Although the sorption isotherms are similar for an as-received 0.3 mil sample studied earlier and for the as-received 2 mil samples studied here, the diffusion coefficient of water in the as-received 2 mil sample is approximately 300% larger than in the as-received 0.3 mil sample. This large effect is believed to be related to the presence of small, paracrystalline aggregates with large aspect ratios. Differences in orientation measured by birefringence for the two samples suggest that the barrier properties of Kapton® are strongly affected by the detailed morphological organization of the ordered aggregates. Comparison of the sorption isotherms for the as-received and hygrothermally aged 2-mil films suggests a significant increase in the hydrophillic nature of the aged film. This change is consistent with an apparent chemical reaction between water and uncyclized amic acid residues in the film. The tendency for water to cluster in as-received Kapton® is essentially eliminated by the chemical modification associated with hygrothermal aging. The hygrothermal aging produces a dramatic reduction in the water vapor diffusion coefficient at low vapor activities but a rather modest change at high activities.

The rheological behavior of the thermotropic liquid crystal copolyesters composed of p-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid (indicated as HBA/HNA) is investigated for three different compositions: 75:25, 58:42, 30:70 (in mol%). The inherent viscosities are 9.2, 5.1, and 7.8 dl/g, respectively. Yield stress is observed for all three samples. This indicates the existence of crystallites in the melt which may be related to the shear thinning viscosity at low shear stress. Melt fracture, and a die swell ratio which increases with shear rate, are also observed at higher temperatures and at low shear stress for the two copolyesters having compositions 75:25 and 30:70. We have also estimated for 30HBA/70HNA at 335°C the entrance pressure loss, Δpent, and ΔPent/δw, where δw is the shear stress at the capillary wall. The large value of ΔPent/δw suggest that HBA/HNA is a highly elastic polymeric material. It is found that both ΔPent and ΔPent/δw increase with shear rate. However, the high elasticity does not account for the disappearance of melt fracture and contraction of die swell at high shear stress. This abnormal phenomenon is ascribed to the formation of a network of crystallites caused by blocky regions in the copolymer.