Two-dimensional electron gas formation in undoped In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As quantum wells

We report on the achievement of a two-dimensional electron gas in completely undoped In[0.75]Al[0.25]As/In[0.75]Ga[0.25]As metamorphic quantum wells. Using these structures we were able to reduce the carrier density, with respect to reported values in similar modulation-doped structures. We found experimentally that the electronic charge in the quantum well is likely due to a deep-level donor state in the In[0.75]Al[0.25]As barrier band gap, whose energy lies within the In[0.75]Ga[0.25]As/In[0.75]Al[0.25]As conduction band discontinuity. This result is further confirmed through a Poisson-Schroedinger simulation of the two-dimensional electron gas structure.Comment: 17 pages, 6 figures, to be published in J. Vac. Sci. Technol.

Growth variations and scattering mechanisms in metamorphic In0.75Ga0.25As/In-0.75 Al0.25As quantum wells grown by molecular beam epitaxy

Modulation doped metamorphic In0.75Ga0.25As/In0.75Al0.25As quantum wells (QW) were grown on GaAs substrates by molecular beam epitaxy (MBE) with step-graded buffer layers. The electron mobility of the QWs has been improved by varying the MBE growth conditions, including substrate temperature, arsenic over pressure and modulation doping level. By applying a bias voltage to SiO2 insulated gates, the electron density in the QW can be tuned from 1×1011 to 5.3×1011 cm−2. A peak mobility of 4.3×105 cm2V−1s−1 is obtained at 3.7×1011 cm−2 at 1.5 K before the onset of second subband population. To understand the evolution of mobility, transport data is fitted to a model that takes into account scattering from background impurities, modulation doping, alloy disorder and interface roughness. According to the fits, scattering from background impurities is dominant while that from alloy disorder becomes more significant at high carrier density

Influence tactics and leadership effectiveness in Turkey and USA : mediating role of subordinate commitment

The purpose of the present research was to investigate managerial influence processes in Turkey and the USA. Two survey studies were conducted to explore three objectives. First, the role of core tactics (rational persuasion, consultation, collaboration, and inspirational appeals) in target commitment was examined. Second, the impact of target commitment on the relationship between influence tactics and leadership effectiveness was investigated. Third, whether previous findings of earlier cross-cultural research with scenarios can be verified with a stronger research method was explored

The role of personality, perceived parental differential treatment, and perceptions of fairness on the quality of sibling relationships among emerging adults

The sibling relationship is one of the longest lasting human relationships with significant influence on an individual’s social and emotional functioning. The current study was designed to examine both personal and parental influences on the sibling relationships of emerging adults. Specifically, it tested the mediating role of fairness evaluations on the links between parental differential treatment, personality and the quality of sibling relationships. A theorized path model was developed, and tested using Structural Equation Modeling. A total of 775 undergraduates at a northeastern university, who nominated a ‘target sibling’, completed the Big Five Inventory, the Lifespan Sibling Relationship Scale, the Sibling Inventory of Differential Experience, and fairness of parenting ratings

ASSESSMENT OF RUBRIC-BASED EVALUATION BY NONPARAMETRIC MULTIPLE COMPARISONS IN FIRST-YEAR EDUCATION IN A JAPANESE UNIVERSITY

The rubrics have become a widely referenced and utilized form of assessment on campuses across internationally. But rubric can be an asset in any classroom and at any education level but it needs to be implemented correctly. Our research question in this study is whether students were evaluated consistently and equally from teacher to teacher using rubric. To answer this research question, we performed statistical estimation using nonparametric multiple comparisons. This article reports on a normalizing rubric evaluation by nonparametric multiple comparisons in a first-year course called “Manaburu I” offered at Kobe Tokiwa University. “Manaburu” is a word coined by us: “manabu” ‘learn’ in Japanese + English able. Thus, “Manaburu” refers to Self-Directed Learning I. In the course, about 20 teachers teach about 350 students (16–17 students per teacher). Students are organized into groups of about 6. It is of course difficult for 20 teachers to evaluate their students consistently among them, making this course an appropriate site for the evaluation. We constructed a rubric for the course, under which teachers were meant to evaluate students, and presented it to both teachers and students. Our research question was whether teachers evaluated students consistently and equally according to the Steel–Dwass estimation method, a strict statistical estimation method for nonparametric multiple comparisons. The results show that teachers do not evaluate students equally. Suggestions for future research, more attention to validity and reliability, a closer focus on learning and research on rubric use in higher education

Edition Studies of F. Burgmüller's “18 Etudes Op. 109”: Comparison of the first "Confidence"

10研究ノートResearch notedepartmental bulletin pape

日本植民地期台湾公学校における「国語科」教育の植民地教育史的・社会言語学的研究

東京都立大学Tokyo Metropolitan University博士（日本語教育学）doctoral thesi