Mobility Extraction and Quantum Capacitance Impact in High Performance Graphene Field-effect Transistor Devices

The field-effect mobility of graphene devices is discussed. We argue that the graphene ballistic mean free path can only be extracted by taking into account both, the electrical characteristics and the channel length dependent mobility. In doing so we find a ballistic mean free path of 300nm at room-temperature for a carrier concentration of ~1e12/cm2 and that a substantial series resistance of around 300ohmum has to be taken into account. Furthermore, we demonstrate first quantum capacitance measurements on single-layer graphene devices

Searching for the parallel growth of cities

Three urban growth theories predict parallel growth of cities. The endogenous growth theory predicts deterministic parallel growth; the random growth theory implies that city growth follows Gibrat’s law with a steady-state distribution; and the hybrid growth theory suggests the co-movement of random city growth. This paper uses the Chinese city size data from 1984-2006 and time series econometric techniques to test for parallel growth. The results from various types of stationarity tests on pooled heterogeneous cities show that city growth is random. However, once growth trend and structural change are taken into account, certain groups of cities with common group characteristics, such as similar natural resource endowment or policy regime, grow parallel.Urban growth; Parallel growth; Zipf’s law; Unit root; Structural change

Research on Social Q&A Community Knowledge Transfer Model Based on Follow Relationship Network

Social Q&A community is the focus of knowledge sharing and knowledge acquisition in the Internet era. The study of user group and community structure of social Q&A community is helpful to discover its model of knowledge transfer and the characteristics of the user group. Based on the study of relevant literature and social Q&A community characteristics, we build social relationships network model and use the method of social network analysis to study user groups. Finally, we find the user characteristics and behavior pattern. Furthermore, we analyze the knowledge transfer model of social Q&A community

Gene Transfer of Calcitonin Gene-Related Peptide Inhibits Macrophages and Inflammatory Mediators in Vein Graft Disease

Vein graft disease is a chronic inflammatory disease and limits the late results of coronary revascularization. Calcitonin gene-related peptide (CGRP) inhibits macrophages infiltrated and inflammatory mediators, we hypothesized that transfected CGRP gene inhibits macrophages infiltrated and inflammatory mediators in vein graft disease. Autologous rabbit jugular vein grafts were incubated ex vivo in a solution of mosaic adeno-associated virus vectors containing CGRP gene (AAV2/1.CGRP) 、escherichia coli lac Z gene (AAV2/1.LacZ) or saline and then interposed in the carotid artery. Intima/media ratio were evaluated at postoperative 4 weeks, Macrophages were marked with CD68 antibody by immunocytochemistry. Inflammatory mediators were mensurated with real-time PCR. Neointimal thickening was significantly suppressed in AAV2/1.CGRP group. Macrophages infiltrated and inflammatory mediators monocyte chemoattractant protein-1 (MCP-1)、tumor necrosis factorα(TNF-α)、inducible nitricoxide synthase (iNOS)、matrix metalloproteinase-9 (MMP-9) was significantly suppressed in AAV2/1.CGRP group.Gene transfected AAV2/1.CGRP suppressed neointimal hyperplasia in vein graft disease by suppressed macrophages infiltrated and inflammatory mediators

Leadership in Public Sector: A Discussion from Theoretical and Practical Aspects

Leadership is a critical component of good public governance (OECD, 2001). Effective leadership can bring greater efficiency and quality of service for the organization as well as the increase in personal satisfaction at work. Moreover, it can develop innovation and ability to adapt to the external environment for government. Therefore, there is a great need to improve the quality of leaders. Effective leadership is determined by both heredity and environment. This paper goes on to prove leadership in public sector can be learned from theoretical and practical aspects. As for the theoretical aspects, some innate traits, such as personality can only explain 30% of the leadership effectiveness, and even some personal traits, such as problem solving skill, expertise can be learned. Environment plays the most important role in the leadership of public sector. Emergence and leadership behaviors can contribute to leadership effectiveness. So a lot of leadership development programs, such as formal training, mentoring and feedback can be used to cultivate leadership