1,722,426 research outputs found
Electrical properties of Al/p-Ge and Al/Methyl Green/p-Ge diodes
No full textMethyl green (MG) film has been grown for the first time on p-Ge semiconductor using a simple and low-cost drop coating method. The current-voltage (I-V) characteristics of Al/p-Ge and Al/MG/p-Ge diodes have been investigated in the temperature range of 20-300K. A potential barrier height as high as 0.82eV has been achieved for Al/MG/p-Ge diode, which has high rectification rate, at room temperature. It is seen that the barrier height of the Al/MG/p-Ge diode at the room temperature is larger than that of Al/p-Ge diode and ideality factor value of 1.14 calculated for Al/MG/p-Ge diode is lower than Al/p-Ge diode. The temperature coefficient of barrier height of the Al/MG/p-Ge diode has been calculated as 2.6meV/K. The evaluation of current-voltage characteristics shows that the barrier height of the diode increases with the increasing temperature
Faraday-configured mode-locked p-Ge laser and p-Ge far-infrared amplifier
No full textA solid-state broad-band amplifier of far-infrared radiation (1.5 - 4.2 THz) based on intersubband transitions of hot holes in p-Ge is demonstrated using two p-Ge active crystals, when one operates as an oscillator and one as an amplifier. A peak gain higher than usual for p-Ge lasers has been achieved using time separated excitation of the oscillator and amplifier. Active mode locking of the p-Ge laser has been achieved in the Faraday configuration of electric and magnetic fields with distinct advantages over Voigt geometry. The 200 ps pulses of 80-110 cm-1 radiation were achieved by local gain modulation from an applied rf electric field at the 454 MHz round trip frequency of the laser cavity
Determination of adiabatic temperature change in MnFe(P,Ge) compounds with pulse-field method
Full text linkFast magnetic measurements performed by means of a 20 T pulse-field magnet provide a good approach for directly monitoring the magnetocaloric effect of the MnFe(P,Ge) compounds. Based on the comparison of magnetization curves obtained either in an adiabatic or isothermal process, we propose that the method introduced by Levitin et al is applicable to determine the adiabatic temperature change for an equivalent field change in first-order magnetic transition materials. More strikingly, experimental results confirm that the first-order nature of the transition in MnFe(P,Ge) alloys is not a limiting factor to the operation frequency of a magnetic refrigerator.Radiation Radionuclides & ReactorsApplied Science
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Tunable thermal hysteresis in MnFe(P,Ge) compounds
Full text linkStructural, magnetic, and magnetocaloric properties of the MnFe(P,Ge) compounds were systematically studied on both bulk alloys and melt-spun ribbons. The experimental results show that the critical behavior of the phase transition can be controlled by changing either the compositions or the annealing conditions. The thermal hysteresis is found to be tunable. It can reach very small values, while maintaining a large magnetocaloric effect in a large range of working temperatures and under field changes that may be produced by conventional permanent magnets. Consequently, an effective way in producing ideal magnetic refrigerants for room-temperature applications is suggested.Radiation, Radionuclides and ReactorsApplied Science
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Compact Tunable P-Ge Laser
No full textInnovations in intracavity wavelength selection in the range 1.5 to 4.2 THz and compact control electronics enable a commercial application for a far-infrared p-Ge laser. ©Optical Society of America
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Broad band p-Ge optical amplifier of terahertz radiation
Full text linkA solid state broad band amplifier of terahertz radiation (1.5-4 THz), based on intersubband transitions of hot holes in p-Ge is demonstrated. The gain is investigated as a function of applied magnetic and electric fields by transmission measurements using a laser system with two p-Ge active crystals, when one operates as an oscillator and one as an amplifier. A peak gain higher than usually reported for p-Ge lasers has been achieved using time separated excitation of the oscillator and amplifier. Distinct differences in gain dependence on applied fields are noted between low- and high-frequency modes of p-Ge laser operation
- …
