Poole-Frenkel Conduction in Cu/Nano-SnO 2

It is well known that metal/Tin-dioxide/metal sandwich structures exhibit a field-assisted lowering of the potential barrier between donor-like center and the conduction band edge, known as the Poole-Frenkel effect. This behavior is indicated by a linear dependence of Iog  on 1/2, where is the current density, and is the applied voltage. In this study, the electrical properties of Cu/nano-SnO2/Cu sandwich structures were investigated through current-voltage measurements at room temperature. Also, an attempt to explore the governing current flow mechanism was tried. Our results indicate that noticeable feature appearing clearly in the current-voltage characterization is the Poole-Frenkel and space-charge-limited conduction mechanisms

Multiple Field Ultra Slow Roll Inflation: Primordial Black Holes From Straight Bulk And Distorted Boundary

We study a model of two-field ultra-slow-roll (USR) inflation bounded by a curve in the field space. Curvature perturbations and non-Gaussianities can be enhanced both during the USR phase and from the inhomogeneities at the boundary. We employ the full non-linear $\delta N$ formalism to calculate the probability distribution function (PDF) for curvature perturbation non-perturbatively and show that the non-linear effects can significantly enhance the abundance of the primordial black holes (PBHs). For large curvature perturbations, the PDF has a universal exponential tail, but for the intermediate values, the PDF -- and, therefore, the abundance of the PBHs -- depend sensitively on the geometry of the boundary.Comment: 7 pages, 5 figure

Determining the Topics and Content of CME Programs in Five Selected Subjects: Comparing the View Points of Experts and Target Group a Tehran University of Medical Sciences Experience

Introduction: One of the most appropriate methods for needs assessment is to assess learners' needs and arrange the educational programs based on their viewpoints. The aim of this study was to determine the topics and content of Continuing Medical Education (CME) programs in five selected subjects by medical education experts and target group, based on the real needs of General Practitioners (GPs) in order to revise CME national programs. Methods: In this cross-sectional applied study, 700 GPs covered by Medical Sciences Universities in Tehran province were studied. A questionnaire consisting of two parts of demographic features and 80 scientific questions regarding their knowledge in five domains of clinical pharmacology, skin diseases, toxicology, emergencies, and forensic medicine was used. The questionnaires were delivered to physicians' offices by trained personnel using a list or by direct referral to offices and then gathered. Three topics in each subject and 15 standard educational contents in total were developed for the target group. Results: There was almost a complete relationship between the opinion of experts and target group in forensic medicine. Some of the first five priorities of the two groups overlapped in skin diseases, forensic medicine, and emergencies. No common viewpoints were observed between experts and target group in pharmacology. In toxicology, there was no common viewpoint in the first three selections of the two groups. Conclusion: Real educational needs of GPs in receiving new information in order to promote their competencies and knowledge were different from those considered by experts. It is recommended to design the educational content for the target groups in the health care field based on their real deficiencies in knowledge and practice and by assessing their views and knowledge