Phase transition and the packing structure of the side mesogenic groups of liquid crystalline side-chain copolymers

Summary Copolymers consisting of cholesteryl 11-methacryloyloxy-undecanoate (ChMO-10) and t-buthyl methacrylate (t-BMA) were studied by DSC method and by small angle X-ray scattering method (SAXS). Although homopolymer (pChMO-10) has two different packing structures which are a single-layer packing structure and a two-layer packing one, copolymers (co-pChMO-10-t-BMA) have only the single layer packing one in their mesophase. Furthermore, transition entropy at a clearing point of co-pChMO-10-t-BMA (80/20) is larger than that of pChMO-10. Adequate distance of the mesogenic groups in the direction of a short axis of the mesogenic groups, produced by introduction of non-mesogenic units, seems to stabilize the single-layer packing structure.     

A survey of usability capability maturity models: implications for practice and research

Improving the position and effectiveness of user-centred design (UCD) in software and product development is a challenge in many companies. One step towards improvements is to carry out a usability capability maturity (UCM) assessment to evaluate the strengths and weaknesses of a development organisation in UCD. While several diverse UCM models have been introduced, little research has been published in the public domain on these models. The paper aims to fill this gap by analysing the main features of the models. The results show that most models represent different approaches - although some of them have the same roots - meaning that understanding one model is not enough to understand the basics of another model. All models can be used for examining the status of UCD in individual development projects. In addition, models provide various means for assessment of the status of UCD in other organisational areas. The level of documentation of models varies a lot, and very few empirical research results exist. Based on the results, implications for practice and research are suggested.     

DEFORMATION OF A PIEZOTHERMOELECTRIC COMPOSITE PLATE CONSIDERING THE COUPLING EFFECT

The response of a thin piezothermoelastic composite plate subjected to stationary thermal and electric fields is investigated. Solutions are based on the classical lamination theory, and both the direct piezoelectric effect and the pyroelectric effect in the constitutive relations of piezothermoelasticity are considered. Numerical results show that these coupled effects have a significant influence on the response of the deflection, and the middle surface deflection with these coupled effects is larger than that without them. The laminate configuration and the number of layers have an influence of the response of the deflection     

Leaching of Lead and Connectivity of Plumbate Networks in Lead Silicate Glasses

The formation of a plumbate network in binary lead silicate glasses was examined based on the leaching behavior of Pb²⁺ in lead silicate glasses over a wide composition region. The effective diffusion coefficient of Pb²⁺ at 40°C was on the order of 10⁻¹⁷ m²/s for PbO<35 mol% glasses, and increased three orders of magnitude for 35–50 mol% PbO contents. Such a steep composition dependence is considered to be because of changes in the medium or longer range structure. That is, it is proposed that the plumbate network forms a percolative 3D network in the composition region to form diffusion paths for the lead ions. In addition, the present results indicate that the lead ion exists as a network former over the entire glass forming composition range of the binary silicate glasses.     

Normalized longitudinal current distributions on microstrip lineswith finite strip thickness

An open microstrip line with finite strip thickness is numerically analyzed by the Green's function technique. The normalized longitudinal current distributions are systematically obtained for the cases of various shape and thickness ratios in the quasi-TEM approximation. The obtained results are illustrated in figures for three surfaces of the thick strip conductor, that is, the lower, side, and upper surfaces. The closed-form expressions are obtained for the normalized longitudinal current distributions by taking a best fit to theoretical results     

A Defect Localization Scheme for Cellular Nanocomputers

Computers with device feature sizes of a few nanometers—so-called nanocomputers—are expected within a few decades, but this expectation is accompanied by the realization that the boundary conditions of such systems differ substantially from those of current VLSI-based computers. Prominent among the concerns is the increased degree of permanent defects that will affect nanocomputers, such as defects caused by imperfections at the manufacturing stage, but also defects occurring later, possibly even during the use of these systems. New techniques to deal with defects are called for, but given the huge number of devices involved, such techniques may need to be self-contained: they need be applicable at local levels without outside control, even while computations continue to take place. This paper proposes an important element in such techniques, i.e. the localization of defects among a huge number of devices. It employs a cellular automaton-based architecture, and uses statistical techniques combined with randomly moving configurations in the cellular space to estimate defect locations.

Cerebral sinus thrombosis in a patient with protein S deficiency: a case report

To investigate the role of occupation as a risk factor for hairy cell leukaemia a case-control study on 121 male, hairy cell leukaemia (HCL) patients, and 484 controls matched for age and sex, was conducted. We found significantly elevated risk for HCL among building painters (OR, 5.7; 95% CI, 1.6-20.8; based on six cases and four controls) and construction workers (OR, 3.3; CI, 1.2-9.2; based on seven cases and eight controls). Farming has been suggested as a risk factor in HCL. In this investigation farmers had an OR of 1.2 (CI, 0.6-2.3) and farm workers an OR of 1.5 (CI, 0.8-2.8). However, having ever worked in farming yielded an OR of 1.8 (CI, 1.1-2.9). Having grown up mainly in a rural area gave an OR of 1.4 (CI, 0.9-2.4). UV light has been suggested as a risk factor for non-Hodgkin's lymphoma (NHL). To evaluate the impact of UV exposure, classification of occupations as indoor, outdoor or mixed indoor/outdoor was made. Outdoor and mixed outdoor/indoor work yielded ORs of 2.3 (1.0-4.9) and 1.6 (1.0-2.5), respectively. When the effect of outdoor/indoor or mixed indoor/outdoor work was analysed using a scoring system the OR was 2.0 (CI, 0.9-4.4) for farmers compared with 0.8 (CI, 0.3-1.9) among non-farmers in the highest scoring group. There was no clear correlation between socioeconomic status as defined by the Swedish Socio-Economic Classification (SEI), and the risk of HCL. As many comparisons were made, the possibility of associations occurring by chance can not be excluded.     

Computer-aided system for the diagnosis of Alzheimer's disease

One of the most serious problems in medical science is an increment of Alzheimer's disease. It is known that the patient's brain atrophy is a result of neural cell loss. It is useful for the diagnosis of Alzheimer's disease to measure the volumes of the brain portions and to display them. We can obtain anatomical information from 2D slice images produced by MRI. We propose a computer-aided system for the diagnosis of Alzheimer's disease. The system consists of: (1) extraction of the portions from MRI data, (2) measurement of the volumes of the portions and then displaying them, and (3) user interface for a medical doctor. In this paper we describe procedures for the above. For extraction of the brain portions we propose the method based on standard region growing algorithm and the method of figure decomposition using the distance value. Comparison of the volumes of our extracted portions with volumes manually measured by a physician shows that the error rate, on the average, is 1.74% for 48 MRI data. We also discuss the 3D display, the measuring range, and the construction of the user interface for a physician. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(4): 32–41, 1997     

Video object segmentation using color-component-selectable learning for self-organizing maps

In this article, self-organizing-map-based video object segmentation is proposed, assuming that either Y-quantification or HSV-quantification can be systematically selected. Given a video sequence, the value of the probability density function for each component value is calculated according to a kernel estimation at the first frame. Some areas randomly chosen from the background are then examined, using each component value, to judge whether or not they include the target object. The quantification is determined so that the frequency of occurrence of false extractions can be reduced. The data presented to the maps are generated based on the selected quantification. Experimental results show that the proposed method recognizes the target object well.     

Simultaneous Edge‐on to Face‐on Reorientation and 1D Alignment of Small π‐Conjugated Molecules Using Room‐Temperature Mechanical Rubbing

In this study, room‐temperature mechanical rubbing is used to control the 3D orientation of small π‐conjugated molecular systems in solution‐processed polycrystalline thin films without using any alignment substrate. High absorption dichroic ratio and significant anisotropy in charge carrier mobilities (up to 130) measured in transistor configuration are obtained in rubbed organic films based on the ambipolar quinoidal quaterthiophene (QQT(CN)4). Moreover, a solvent vapor annealing treatment of the rubbed film is found to improve the optical and charge transport anisotropy due to an increased crystallinity. X‐ray diffraction and atomic force microscopy measurements demonstrate that rubbing does not only lead to an excellent 1D orientation of the QQT(CN)4 molecules over large areas but also modifies the orientation of the crystals, moving molecules from an edge‐on to a face‐on configuration. The reasons why a mechanical alignment technique can be used at room temperature for such a polycrystalline film are rationalized, by the plastic characteristics of the QQT(CN)4 layer and the role of the flexible alkyl side chains in the molecular packing. This nearly complete conversion from edge‐on to face‐on orientation by mechanical treatment in polycrystalline small‐molecule‐based thin films opens perspectives in terms of fundamental research and practical applications in organic optoelectronics.