Reversible writing of high-mobility and high-carrier-density doping patterns in two-dimensional van der Waals heterostructures

A key feature of two-dimensional materials is that the sign and concentration of their carriers can be externally controlled with techniques such as electrostatic gating. However, conventional electrostatic gating has limitations, including a maximum carrier density set by the dielectric breakdown, and ionic liquid gating and direct chemical doping also suffer from drawbacks. Here, we show that an electron-beam-induced doping technique can be used to reversibly write high-resolution doping patterns in hexagonal boron nitride-encapsulated graphene and molybdenum disulfide (MoS2) van der Waals heterostructures. The doped MoS2 device exhibits an order of magnitude decrease of subthreshold swing compared with the device before doping, whereas the doped graphene devices demonstrate a previously inaccessible regime of high carrier concentration and high mobility, even at room temperature. We also show that the approach can be used to write high-quality p–n junctions and nanoscale doping patterns, illustrating that the technique can create nanoscale circuitry in van der Waals heterostructures

Generating Diffusion MRI scalar maps from T1 weighted images using generative adversarial networks

Diffusion magnetic resonance imaging (diffusion MRI) is a non-invasive microstructure assessment technique. Scalar measures, such as FA (fractional anisotropy) and MD (mean diffusivity), quantifying micro-structural tissue properties can be obtained using diffusion models and data processing pipelines. However, it is costly and time consuming to collect high quality diffusion data. Here, we therefore demonstrate how Generative Adversarial Networks (GANs) can be used to generate synthetic diffusion scalar measures from structural T1-weighted images in a single optimized step. Specifically, we train the popular CycleGAN model to learn to map a T1 image to FA or MD, and vice versa. As an application, we show that synthetic FA images can be used as a target for non-linear registration, to correct for geometric distortions common in diffusion MRI

Fast Predictive Image Registration

We present a method to predict image deformations based on patch-wise image appearance. Specifically, we design a patch-based deep encoder-decoder network which learns the pixel/voxel-wise mapping between image appearance and registration parameters. Our approach can predict general deformation parameterizations, however, we focus on the large deformation diffeomorphic metric mapping (LDDMM) registration model. By predicting the LDDMM momentum-parameterization we retain the desirable theoretical properties of LDDMM, while reducing computation time by orders of magnitude: combined with patch pruning, we achieve a 1500x/66x speed up compared to GPU-based optimization for 2D/3D image registration. Our approach has better prediction accuracy than predicting deformation or velocity fields and results in diffeomorphic transformations. Additionally, we create a Bayesian probabilistic version of our network, which allows evaluation of deformation field uncertainty through Monte Carlo sampling using dropout at test time. We show that deformation uncertainty highlights areas of ambiguous deformations. We test our method on the OASIS brain image dataset in 2D and 3D

Longevity of the Permian Emeishan mantle plume (SW China): 1 Ma, 8 Ma or 18 Ma?

After the formation of the ∼ 260 Ma Emeishan large igneous province, there were two volumetrically minor magmatic pulses at ∼ 252 Ma and ∼ 242 Ma, respectively. Alkaline mafic dykes intruding both 260 Ma and 252 Ma felsic plutons in the Panxi region, southwestern China, have compositions similar to the Emeishan flood basalts. One dyke is dated using the SHRIMP zircon U-Pb technique at 242 ± 2 Ma, ∼ 18 Ma younger than the start of Emeishan magmatism. The dykes have enriched light rare earth element patterns (La/YbN = 4.4-18.8) and trace element patterns similar to the Emeishan flood basalts and average ocean-island basalts. Some trace element ratios of the dykes (Zr/Nb = 3.8-8.2, La/Nb = 0.4-1.7, Ba/La = 7.5-25.6) are somewhat similar to EM1 source material, however, there are differences. Their εNd values (εNd = +2.6 and +2.7) and ISr( ISr = 0.704542 and 0.704554) ratios are indicative of a mantle source. Thus Emeishan magmatism may have lasted for almost 20 Ma after the initial eruption. However, geological evidence precludes the possibility that the post-260 Ma magmatic events were directly related to Emeishan magmatism, which began at and ended shortly after 260 Ma. The 252 Ma plutons and 242 Ma dykes represent volumetrically minor melting of the fossil Emeishan plume-head beneath the Yangtze crust. The 252 Ma magmatic event was likely caused by post-flood basalt extension of the Yangtze crust, whereas the 242 Ma event was caused by decompressional melting associated with the collision between the South China and North China blocks during the Middle Triassic. © 2008 Cambridge University Press.published_or_final_versio

Geochemistry of the Early Paleozoic Baiyin Volcanic Rocks (NW China): Implications for the Tectonic Evolution of the North Qilian Orogenic Belt

The Qilian Mountains in NW China comprise the North Qilian Orogenic Belt, Central Qilian Block, and South Qilian Orogenic Belt. The North Qilian Orogenic Belt consists of the Northern and Southern terranes separated by a volcanic rock belt. This belt is composed mainly of felsic and mafic volcanic rocks. Volcanic rocks in the Baiyin area of the eastern part of the belt include rhyolites, rhyodacite, andesitic basalts, and basalts. New zircon U-Pb isotopic data yield a crystallization age of ca. 445 Ma for the rhyolite, 30 m.yr. younger than the associated basalts. The mafic volcanic rocks are relatively enriched in Th, Sr, and light rare earth element with (La/Yb) N ratios ranging from 4.2 to 5.6 and LaN ranging from 40 to 49, and depleted in high field strength elements, with high Th/Nb ratios (0.9-1.3). These features together with their εNd(T) values (-1.4 to +3.1) are consistent with a subduction-related origin, most likely in a mature island arc or an arc built on thin continental crust in an active continental margin. The felsic volcanic rocks show a calc-alkaline affinity and a strong suprasubduction zone signature with negative Nb, Sr, and Ti anomalies and relatively high Th/Nb ratios (0.8-1.6). They have significantly high εNd(T) values (+4.4 to +7.7) relative to the mafic volcanic rocks. Such radiogenic Nd isotopic compositions rule out a crustal origin and indicate the derivation from a depleted mantle source in a volcanic arc environment. Therefore, the geochemistry of the mafic and felsic volcanic rocks demonstrates an Ordovician volcanic arc above a northward subduction zone. The northward drifting of the Central Qilian Block eventually resulted in the amalgamation of the Northern and Southern terranes to form the North Qilian Orogenic Belt in the Early Paleozoic. © 2005 by The University of Chicago. All rights reserved.published_or_final_versio

Inductive Charging Coupler with Assistive Coils

© 2016 IEEE. A wireless charging system contains a high-frequency power source, a wireless transformer/coupler, a rectifier, and the load. The wireless transformer/coupler is the key element of the wireless charging system, and the power source and the rectifier design are all dependent on its design. For a two coil type wireless transformer, the maximum efficiency is limited by the coupling coefficient, which rapidly decreases with increasing distance between the primary and secondary coils. The four coil system is widely used in low-power applications, where the maximum power transfer operating point is away from the maximum efficiency point. This paper proposes an inductive charging coupler with small assistive coils, where the high power and maximum efficiency regions overlap

Neoproterozoic Mafic-Ultramafic Intrusions from the Fanjingshan Region, South China: Implications for Subduction-Related Magmatism in the Jiangnan Fold Belt

published_or_final_versio

Dynamic marketing capabilities, foreign ownership modes, sub-national locations and the performance of foreign affiliates in developing economies

Purpose – The purpose of this paper is to examine the role of dynamic marketing capabilities (DMC), foreign ownership modes and sub-national locations on the performance of foreign owned affiliates (FOAs) in developing economies. Design/methodology/approach – Based on a sample of 254 FOAs in Indian manufacturing sector (covering the period of 2000-2008 leading to 623 firm-year observations), the empirical paper adopts the panel data regression approach. Findings – The study confirms the significant importance of DMC to assist FOAs to gain better sales performance in an emerging market such as India. The findings indicate that Wholly Owned Foreign Affiliates (WOFAs) have better sales performance than International Joint Venture (IJV), and Majority-owned IJV (MAIJV) perform better than Minority-owned IJV (MIIJV) in the Indian manufacturing sector. The results confirm that effective deployment of DMC leads to better sales performance in WOFAs and to some extent in MAIJVs compared to MIIJVs. Perhaps the most interesting finding is that developing DMC in non-Metropolitan areas is associated with higher sales growth than in Metropolitan locations. Originality/value – The study contributes to the literature by examining the impact of DMC on performance of FOA by considering the organised manufacturing sector in a large and fast growing developing economy. In addition, the results for the moderating effects provide novel evidence of the conditions under which DMC of FOA interacts with different ownership modes and influence firm performance

Geochemical Constrains on Nature of Source Region of The Late Permian Emeishan Continental Flood Basalts, SW China

Abstract in http://www.lpi.usra.edu/meetings/gold2001/pdf/3488.pd

Widely tunable dual-wavelength optical short pulse generation in a self-seeding scheme

Author name used in this publication: Dong Ning Wang2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe