40 GHz, low half-wave voltage Ti:LiNbO/sub 3/ intensity modulator

A 5 V half-wave voltage (V/sub pi /) electro-optic Ti:LiNbO/sub 3/ intensity modulator with a -7.5 dB (electrical) optical response at 40 GHz is demonstrated at 1.3 mu m. A thick electrode structure is used in conjunction with a thin substrate to achieve a near optical-microwave phase match and a broadband electrical response.<>     

Reliability: Is it worth the effort? An assessment of the value of reliability tasks and techniques

This paper describes a number of reliability tasks and techniques, including reliability modeling and prediction, FMECA, ESS, failure analysis, redundancy, and others. Each of these is examined to assess its usefulness and general cost-effectiveness. Suggestions are offered for deciding whether or not to use any of these tasks and techniques during the design and manufacture of commercial equipment.     

CDI: linking material property databases to analysis codes

Integration among programs designed to solve complex engineering problems is often lacking, and this is particularly a problem in the area of thick composite materials analysis and design where a large volume of inout must be provided. Another problem is the lack of an archival repository in which to store input information in a generic format. To address these problems, we have developed a prototype of a finite element material property reprocessing system, called the composites data-base interface (CDI). In this computer-aided analysis system, a materials database is integrated with several software components, including commercially available finite element analysis (FEA) programs and preprocessors, and tools for manipulating and using composite materials data, resulting in the transfer of two- and three-dimensional composite materials property data into an FEA program. This paper presents the capabilities of this system, discusses the overall system integration through R:BASE, and provides a civil engineering application involving the design of a large cylindrical tank to illustrate the execution of the CDI system's various components. The paper ends by discussing the current status of this computer-aided analysis system.     

Overview.

The Association for Play Therapy (APT) and its International Journal of Play Therapy are taking giant steps forward! One of the fundamental objectives of national mental health associations is to generate and widely disseminate research and other clinical information to academics, practitioners, and students. To accomplish this aim, our peer-reviewed journal continues to feature articles regarding the latest play therapy research, case studies, theoretical application, and current practices authored by mental health professionals with play therapy expertise. This article is an overview of future plans for the journal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Protein kinase C isotypes in human erythroleukemia (K562) cell proliferation and differentiation. Evidence that beta II protein kinase C is required for proliferation

The human erythroleukemia (K562) cell line undergoes megakaryocytic differentiation and cessation of proliferation when treated with phorbol myristate acetate (PMA). To investigate the role of individual protein kinase C (PKC) isotypes in these events, we have assessed PKC isotype expression during leukemic proliferation and PMA-induced differentiation. Immunoblot analysis using isotype-specific antibodies demonstrates that proliferating K562 cells express the alpha, beta II, and zeta PKC isotypes. PMA-induced differentiation and cytostasis lead to a decrease in beta II PKC and increases in alpha and zeta PKC levels. The role of the alpha and beta II PKC isotypes was further assessed in cells overexpressing these isotypes. K562 cells overexpressing human alpha PKC grew more slowly and were more sensitive to the cytostatic effects of PMA than control cells, whereas cells overexpressing beta II PKC were less sensitive to PMA. PMA-induced cytostasis is reversed upon removal of PMA. Resumption of proliferation is accompanied by reexpression of beta II PKC to near control levels, whereas alpha and zeta PKC levels remain elevated for several days after removal of PMA. Proliferation of PMA-withdrawn cells can be partially inhibited by antisense beta II PKC oligodeoxyribonucleotide. Growth inhibition is dose-dependent, specific for beta II PKC-directed antisense oligonucleotide, and associated with significant inhibition of beta II PKC levels indicating that beta II PKC is essential for K562 cell proliferation. Sodium butyrate, which unlike PMA induces megakaryocytic differentiation without cytostasis, causes increases in both alpha and beta II PKC levels. These data demonstrate that beta II PKC is required for K562 cell proliferation, whereas alpha PKC is involved in megakaryocytic differentiation.     

A color graphics display of the field intensity around theinsulator on 13.2 kV distribution lines

Covered conductors have been used, especially in wooded areas on low as well as high voltage overhead distribution lines for preventing brush contact and short circuit faults between conductors. Burndown on covered conductors has become a significant problem. The burndown mechanism is complicated since it is determined by combinations of the various types of insulators, ties, and conductors. In order to investigate the burndown mechanism, a finite element analysis is carried out to identify the electric field around the insulator. A newly developed electric field digital simulation system is reported in which a finite element analysis method considering isoparametric triangular and line elements is developed. A new color display method for electric potential and electric field distributions with lines of electric force is also described as a means of observing the results     

Caries prevalence in preschool children in industrial cities

Caries incidence was analyzed in preschool children attending kindergartens living in two industrial towns differing by the level and specific features of air pollution and by fluorine levels in potable water. Caries incidence was found to be higher in a ferrous metallurgy center with very low (0.1 to 0.3 ml/l) fluorine levels in potable water. Passive smoking factor was found to contribute to development of caries in children, particularly so in girls. Motor car transport effects on caries development in children were not confirmed. Recommendations on reduction of caries development intensity are suggested.     

Electrophoretic separations using sweeping fields

Sweeping-field electrophoresis is investigated as a method for increasing the resolution of low-voltage slab gel separations. In this technique a low direct current (DC) voltage is time multiplexed to an array of periodically spaced electrodes placed along the length of the slab in a manner that follows the band migration. Because the electrode spacing is smaller than the slab length, a larger field is generated, yielding an improved separation. The effect of the nonuniform electric field on band distortion is studied in some detail. Experimental band distortion results showed good agreement with theoretical predictions in a macroscopic sweeping-field electrophoresis system. Both analytical and numerical results show that band distortion can be effectively minimized when an appropriate sweep rate is selected for a narrow band range. Using this scheme we have achieved the same number of theoretical plates as a DC-driven system with one third of the drive voltage.     

Nanoindentation technique for measuring residual stress field around a laser-induced crack in fused silica

A nanometre scale indentation technique using microprobe indentations to measure residual stresses at selected positions near u.v.-laser-induced cracks in fused silica is presented. The approach is based on the observation that the nanoindentations' penetration depths are affected by the residual stress field emanating from the laser-induced crack. A simple theoretical model based on the change of the nanoindentation penetration depth as well as the change in Young's modulus and hardness of the material is derived. The results show good agreement with the inclusion model [15] suggesting that the residual stress field around a laser-induced crack in fused silica is of shear nature. An exploratory test made on an unstressed sample (free of a laser-induced crack), yielding values for Young's modulus and hardness in accordance with handbook values, shows the high accuracy of this nanoindentation diagnostic.