A power sharing series power BJT array with isolated low voltage control for AC power control applications

A technique for a continuously variable AC resistance using a series BJT array is presented. This array provides high power dissipation capability and uniform voltage and power distribution across the individual transistors. The array, controlled using a set of optoisolators to maintain the electrical isolation between the control circuits and the power stage, could be used as the basis to develop several useful techniques including a solid state AC regulator with comparable performance to the commonly used ferro-resonant systems; a linear AC electronic load suitable for testing UPS and other power conditioners; and, in other AC power control applications such as switching capacitors in AC resonant circuits

Fabrication of high-quality-factor photonic crystal microcavities in InAsP/InGaAsP membranes

Optical fiber taper waveguides are used to improve the efficiency of room temperature photoluminescence measurements of AlGaAs microdisk resonant cavities with embedded self-assembled InAs quantum dots. As a near-field collection optic, the fiber taper improves the collection efficiency from microdisk lasers by a factor of ∼15–100 times in comparison to conventional normal incidence free-space collection techniques. In addition, the fiber taper can serve as an efficient means for pumping these devices, and initial measurements employing fiber pumping and collection are presented. Implications of this work towards chip-based cavity quantum electrodynamics experiments are discussed

A Study of the Attitudes of the Adventist Church Members in Taiwan Toward the Support of Seventh-day Adventist Christian Education

Problem. The Seventh-day Adventist denomination has developed a school system to serve theindividual needs of its members and general needs of the church. From 1972 to 1986, the educational work of the Adventist church in Taiwan has declined steadily. This study was to investigate the attitudes of church members toward the support of Adventist education on relation to demographic and personal variables. Method. The Adventist Christian Education Attitude Scale measured (1) demographic characteristics; (2) 59 attitude statements, arranged in five scales, identified by factor analysis; and (3) the 13 reasons why church members did not attend or send their youth to Adventistschools. Questionnaires were mailed to 495 church members, 457 of whom responded. The 18 null hypothesis were tested by the t-test for independent means and one-way analysis ofvariance, each hypothesis was tested at an alpha level of.05. Results. This study revealed the following: (1) Of the five identified areas of church members\u27 attitude toward Adventist education, the Christ-centered education and character building of children and youth was ranked highest; the curriculum offering and teacher qualifications lowest. (2) There was a significant difference in attitudes toward the support of Adventist education inrelation to 17 demographic and personal characteristics. (3) The first five reasons why church members do not attend or do not send their youth to Adventist schools were: (a) the schools are not officially recognized by the Taiwan government; (b) opportunity to find a job after graduation is limited; (c) the cost for Adventist education is too burdensome; (d) the curriculum offering is limited; and (e) teachers are inadequately qualified. Conclusions. The major conclusions were: (1) Ministers and teachers had a more favorable attitude than members in other occupations toward the support of Adventist education. (2) Parents who were members of the Adventist church had a more positive attitude toward Adventist education than those parents who had other religious affiliations. (3) Church memberswho had attended an Adventist school for a longer period of time reported a higher degree of support for Adventist schools than those who had attended an Adventist school for a shorter period of time. (4) Church members who had attended an Adventist college had a more negative attitude toward the Adventist education than those who had not

B-2 Serving Leadership Style Revisited

This presentation highlights findings from a study exploring the congregational health and church growth of more than 9,000 congregations from various denominations across United States. These congregations have used a Natural Church Development (NCD) survey to obtain a health assessment over the period of last 10 years. Findings reveal a fascinating pattern of church growth and health that is related to leadership style of the pastor. The data show that the churches whose pastors say their style of leadership is serving are actually growing less and have lower health scores than those who do not list their leadership style as serving. Serving as pastor’s style of leadership predicts smaller size of church attendance

Radiating sources in higher-dimensional gravity

We study a time-dependent 5D metric which contains a static 4D sub-metric whose 3D part is spherically symmetric. An expansion in the metric coefficient allow us to obtain close-to Schwarzschild approximation to a class of spherically-symmetric solutions. Using Campbell's embedding theorem and the induced-matter formalism we obtain two 4D solutions. One describes a source with the stiff equation of state believed to be applicable to dense astrophysical objects, and the other describes a spherical source with a radial heat flow.Comment: Latex, 20 pages, no figures. to appear in J. Math. Phy

Quasi-exactly solvable quasinormal modes

We consider quasinormal modes with complex energies from the point of view of the theory of quasi-exactly solvable (QES) models. We demonstrate that it is possible to find new potentials which admit exactly solvable or QES quasinormal modes by suitable complexification of parameters defining the QES potentials. Particularly, we obtain one QES and four exactly solvable potentials out of the five one-dimensional QES systems based on the $sl(2)$ algebra.Comment: 3 pages, no figures. To appear in the Proceedings of the 13th International Symposium on Particles, Strings and Cosmology (July 2-7, 2007, Imperial College, London

Experimental demonstration of a high quality factor photonic crystal microcavity

Sub-threshold measurements of a photonic crystal (PC) microcavity laser operating at 1.3 microns show a linewidth of 0.10 nm, corresponding to a quality factor Q ~ 1.3x10^4. The PC microcavity mode is a donor-type mode in a graded square lattice of air holes, with a theoretical Q ~ 10^5 and mode volume Veff ~ 0.25 cubic half-wavelengths in air. Devices are fabricated in an InAsP/InGaAsP multi-quantum well membrane and are optically pumped at 830 nm. External peak pump power laser thresholds as low as 100 microWatts are also observed