arXiv subjects

Ju Gao

Publications and source records attributed to Ju Gao.

26 records · Page 2Linked to original sources

arXiv2018

Automatic Severity Classification of Coronary Artery Disease via Recurrent Capsule Network

Coronary artery disease (CAD) is one of the leading causes of cardiovascular disease deaths. CAD condition progresses rapidly, if not diagnosed and treated at an early stage may eventually lead to an irreversible state of the heart muscle death. Invasive coronary arteriography is the gold standard technique for CAD diagnosis. Coronary arteriography texts describe which part has stenosis and how much stenosis is in details. It is crucial to conduct the severity classification of CAD. In this paper, we employ a recurrent capsule network (RCN) to extract semantic relations between clinical named entities in Chinese coronary arteriography texts, through which we can automatically find out the maximal stenosis for each lumen to inference how severe CAD is according to the improved method of Gensini. Experimental results on the corpus collected from Shanghai Shuguang Hospital show that our proposed method achieves an accuracy of 97.0\% in the severity classification of CAD.

cs.CL↗

arXiv2018

Fast and Accurate Recognition of Chinese Clinical Named Entities with Residual Dilated Convolutions

Clinical Named Entity Recognition (CNER) aims to identify and classify clinical terms such as diseases, symptoms, treatments, exams, and body parts in electronic health records, which is a fundamental and crucial task for clinical and translation research. In recent years, deep learning methods have achieved significant success in CNER tasks. However, these methods depend greatly on Recurrent Neural Networks (RNNs), which maintain a vector of hidden activations that are propagated through time, thus causing too much time to train models. In this paper, we propose a Residual Dilated Convolutional Neural Network with Conditional Random Field (RD-CNN-CRF) to solve it. Specifically, Chinese characters and dictionary features are first projected into dense vector representations, then they are fed into the residual dilated convolutional neural network to capture contextual features. Finally, a conditional random field is employed to capture dependencies between neighboring tags. Computational results on the CCKS-2017 Task 2 benchmark dataset show that our proposed RD-CNN-CRF method competes favorably with state-of-the-art RNN-based methods both in terms of computational performance and training time.

cs.CL↗

arXiv2015

Raman fingerprint of semi-metal WTe2 from bulk to monolayer

Tungsten ditelluride (WTe2), a layered transition-metal dichalcogenide (TMD), has recently demonstrated an extremely large magnetoresistance effect, which is unique among TMDs. This fascinating feature seems to be correlated with its special electronic structure. Here, we report the observation of 6 Raman peaks corresponding to the A_2^4, A_1^9, A_1^8, A_1^6, A_1^5 and A_1^2 phonons, from the 33 Raman-active modes predicted for WTe2. This provides direct evidence to distinguish the space group of WTe2 from that of other TMDs. Moreover, the Raman evolution of WTe2 from bulk to monolayer is clearly revealed. It is interesting to find that the A_2^4 mode, centered at ~109.8 cm-1, is forbidden in a monolayer, which may be attributable to the transition of the point group from C2v (bulk) to C2h (monolayer). Our work characterizes all observed Raman peaks in the bulk and few-layer samples and provides a route to study the physical properties of two-dimensional WTe2.

cond-mat.mtrl-sci↗

arXiv2007

Ponderomotive tunneling in electron-laser interactions

It is known that the ponderomotive potential from the laser electron interaction behaves like a static potential that scatters off electrons. We have investigated the process of the electron tunneling the ponderomotive potential by using the nonperturbative quantum electrodynamic approach with a modified Gaussian quantized laser field. The results show that the ponderomotive tunneling is significantly larger than the tunneling of a static potential of the same profile. The tunneled electron is discrete in energy spectrum and spatial diffraction as the result of multiphoton processes. A resonant tunneling occurs when the ponderomotive energy equals the multiple integer of the laser photon energy.

quant-ph↗

arXiv2006

Classical Field Theory of Cerenkov Radiation Devices

The usually continuous and incoherent Cerenkov radiation (CR) is converted into coherent and narrow-band radiation from within a dielectric-line cavity excited by a dc electron beam. We have studied the self-oscillating behavior of a device that operates at $\sim22$ GHz by calculating explicitly the electron self-bunching and radiation growing processes. The nonlinear gain of the device and the radiation spectrum are also calculated. The agreement to the experiments indicates that the developed formalism could be used in designing a THz source based on cavity Cerenkov radiation.

physics.plasm-ph↗

arXiv2005

Quantum Properties of Cavity Cerenkov Radiation

Cerenkov radiation from cavities have been analyzed by quantum electrodynamic theory. Analytical expressions of some basic radiation properties including Einstein's $A$ and $B$ coefficients are derived and shown to be directly modified by the cavities. Coherent and incoherent radiations are analyzed with the aim of generating THz radiation from the devices.

physics.optics↗

arXiv2004

Effects of spin imbalance on the electric-field driven quantum dissipationless spin current in $p$-doped Semiconductors

It was proposed recently by Murakami et al. [Science \textbf{301}, 1348(2003)] that in a large class of $p$-doped semiconductors, an applied electric field can drive a quantum dissipationless spin current in the direction perpendicular to the electric field. In this paper we investigate the effects of spin imbalance on this intrinsic $spin$ Hall effect. We show that in a real sample with boundaries, due to the presence of spin imbalance near the edges of the sample, the spin Hall conductivity is not a constant but a sensitively $position$-$dependent$ quantity, and due to this fact, in order to take the effects of spin imbalance properly into account, a microscopic calculation of both the quantum dissipationless spin Hall current and the spin accumulation on an equal footing is thus required. Based on such a microscopic calculation, a detailed discussion of the effects of spin imbalance on the intrinsic spin Hall effect in thin slabs of $p$-doped semiconductors are presented.

cond-mat.mes-hall↗

arXiv2004

Conductance modulation in spin field-efect transistors under finite bias voltages

The conductance modulations in spin field-effect transistors under finite bias voltages were studied. It was shown that when a finite bias voltage is applied between two terminals of a spin field-effect transistor, the spin precession states of injected spin-polarized electrons in the semiconductor channel of the device will depend not only the gate-voltage controlled Rashba spin-orbit coupling but also depend on the bias voltage and, hence, the conductance modulation in the device due to Rashba spin-orbit coupling may also depend sensitively on the bias voltage.

cond-mat.mes-hall↗