摘要：
The effect of local toroidal flow (LTF) on double-tearing modes (DTMs) is investigated in cylindrical geometry using the reduced magnetohydrodynamics (RMHD) model. The results indicate that the LTF between the two rational surfaces is the dominant suppression effect on DTMs. The suppression effect is enhanced with the flow width increasing, and the DTMs become more stable with the increase of the shear of the LTF between the two rational surfaces. So, in the reversed shear magnetic field configuration, the local flow is driven between the two rational surfaces, which can effectively suppress the development of DTMs and maintain the high-performance state.
摘要：
Analytical drain current and capacitance model is developed for the amorphous InGaZnO (a-IGZO) thin-film transistor (TFT). The numerical Pao-Sah model is presented to describe the temperature characteristics considering the deep and tail trap states in the energy gap of the a-IGZO thin film. The numerical model is successful for the TFT in both the subthreshold regime and the above-threshold regime. In the subthreshold regime, considering that the trapped electron concentration in the deep trap states dominates the Poisson's equation, the surface-potential-based analytical model is presented. In the above-threshold regime, the threshold-voltage-based analytical model is presented. Applying the smooth function to connect the subthreshold model and the above-threshold model, the analytical compact model is obtained. The compact model is verified by the numerical Pao-Sah model and the available experimental data from 253 to 393 K. Furthermore, the temperature characteristics of the field-effect mobility are discussed.
摘要：
This study is aimed to investigate the microstructure of UO2 pellet cut by fiber laser and subsequent nitric acid solubility. A high power laser cutting system was employed to cut fuel rod which consists of stainless steel cladding and UO2 pellets. The influences of assist gas and cutting speed on the micromorphology, element distribution and phase of the cut-off surface of UO2 pellet were discussed. And the nitric acid solubility of laser cut samples was also studied. The results showed that there are defects such as shrinkage micro-pore, fragment, cave and crack on the cut-off surface of UO2 pellet, and UO2 may be converted into U3O8. However, subsequent nitric acid dissolution experiments demonstrated that the laser cut-off samples were soluble in nitric acid, and solubility and the dissolution rate were almost the same as those of the pristine UO2 pellets. This study illustrate that the laser can be employed to cut the fuel rod with the composite structure composed of stainless steel cladding and UO2 pellets with appropriate process parameters, and it has no adverse effect on subsequent nitric acid dissolution process.
摘要：
Floquet theory combined with the generalized Van Vleck nearly degenerate perturbation theory has been widely employed for studying various two-level systems that are driven by external fields via time-dependent longitudinal (i.e., diagonal) couplings. However, three-level systems strongly driven by time-dependent transverse (i.e., off-diagonal) couplings have rarely been investigated, due to the breakdown of the traditional rotating wave approximation. Meanwhile, the conventional perturbation theory is not directly applicable, since a small parameter for the perturbed part is no longer apparent. Here we develop a double-unitary-transformation approach to deal with periodically modulated and strongly driven systems, where the time-dependent Hamiltonian has large off-diagonal elements. The first unitary transformation converts strong off-diagonal elements to diagonal ones, and the second enables us to harness the generalized Van Vleck perturbation theory to deal with the transformed Floquet matrix and also allows us to reduce the infinite-dimensional Floquet Hamiltonian to a finite effective one. For a strongly modulated three-level system, with the combination of the Floquet theory and the transformed generalized Van Vleck perturbation theory, we obtain analytical results of the system, which agree well with exact numerical solutions. This method offers a useful tool to analytically study multilevel systems with strong transverse couplings.
期刊：
Science and Technology of Nuclear Installations,2020年2020 ISSN：1687-6075
通讯作者：
Zeng, Tiejun;Wan, Yaping
作者机构：
[Yang, Xiaohua; Zeng, Tiejun] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Zeng, Tiejun] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Yang, Xiaohua; Wan, Yaping] CNNC Key Lab High Trusted Comp, Hengyang 421001, Peoples R China.;[Yang, Xiaohua; Liu, Zhenghai; Wan, Yaping; Mao, Yu] Univ South China, Sch Comp, Hengyang 421001, Peoples R China.
通讯机构：
[Zeng, Tiejun; Wan, Yaping] U;[Wan, Yaping] C;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;CNNC Key Lab High Trusted Comp, Hengyang 421001, Peoples R China.
摘要：
This paper proposes to design security measures based on the radioactive material package as the basic unit. The principle of four-layer defense in depth is put forward. Based on the concept of self-security intelligence, combined with out-of-vehicle monitoring, in-vehicle monitoring, and Beidou positioning technology, a security system for transport of radioactive materials was designed. It realized the perception, early warning, delay, and alarm functions and greatly improved the security.
期刊：
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY,2020年231:117800 ISSN：1386-1425
通讯作者：
Guo, Wei
作者机构：
[Guo, Wei; Li, Changming] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Zhou, Panwang; Li, Changming; Tang, Zhe] Shandong Univ, Inst Mol Sci & Engn, Qingdao 266235, Peoples R China.;[Zhou, Panwang] Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Mol React Dynam, Dalian 116023, Peoples R China.
通讯机构：
[Guo, Wei] U;Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
关键词：
Concerted mechanism;Excited state proton transfer;Potential energy surface;Stepwise mechanism;TDDFT
摘要：
Time-dependent density functional theory (TDDFT) method was used to study the different excited states proton transfer mechanism of DPP in cyclohexane (CHE) and Methanol (MeOH). The results indicate that the concerted mechanism and the stepwise mechanism coexist in the double proton transfer process of DPP dimer in the aprotic solvent CHE, the stepwise mechanism predominates. The stepwise mechanism can only carry out single proton transfer (DPP-SFr), the second proton cannot be transferred because it is hindered by high energy barriers. The concerted mechanism produces a double proton transfer (DPP-DPT). The potential energy surface of the DPP dimer was calculated and the double fluorescence phenomenon of DPP dimer observed by Chou et al. (P.T. Chou, Y.I. Liu, H.W. Liu, W.S. Yu. Dual Excitation behavior of double proton transfer versus Charge Transfer in 4-( N-Substituted Amino)-1H-pyrroloi 2.3-bipyridines tuned by dielectric and hydrogen-bonding perturbation, J. Am. Chem. Soc., 123 (2001) 12119-12120) was explained. In view of the protonic solvent effect of methanol, the potential energy curve of the DPP/MeOH cluster was constructed. The fluorescence quenching process of DPP/MeOH clusters was elucidated. The proton transfer pathways of DPP/Me0H clusters are revealed in two different concerted ways (Type A: protons transfer from DPP molecules to Me0H solvent molecules; Type B: protons transfer from MeOH solvent to DPP molecules). The ESPT process of DPP molecules in the protic solvent Me0H was found to be more prone to Type B. The results can help to better understand the intermolecular hydrogen bonding mechanism of DPP molecules. (C) 2019 Elsevier B.V. All rights reserved.
作者：
Yang Jin;Chen Jun;Wang Fu-Di;Li Ying-Ping;Lyu Bo*;...
期刊：
物理学报,2020年69(5):126-132 ISSN：1000-3290
通讯作者：
Xiang Dong;Lyu Bo
作者机构：
[Yang Jin; Xiang Dong; Wang Xun-Yu; Gong Xue-Yu; He Liang] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Fu Jia; Yang Jin; Lyu Bo; Chu Yu-Qi; Zang Qing; Bin Bin; Liu Hai-Qing; Wang Fu-Di; Zhang Hong-Ming; Wang Xun-Yu; Wan Shun-Kuan; Li Ying-Ping; He Liang; Chen Jun; Liu Jian-Wen] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.;[Ye Min-You; Chen Jun] Univ Sci & Technol China, Dept Engn & Appl Phys, Hefei 230026, Peoples R China.;[Yin Xiang-Hui] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Xiang Dong] U;[Lyu Bo] C;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.
期刊：
IEEE INTERNET OF THINGS JOURNAL,2020年7(10):9919-9929 ISSN：2327-4662
通讯作者：
Yi, Lingzhi
作者机构：
[Deng, Xianjun; Jiang, Yalan] Univ South China, Sch Elect Engn, Hunan Prov Key Lab Ultrafast Micro Nano Technol &, Hengyang 421001, Peoples R China.;[Yang, Laurence T.; Yi, Lingzhi] St Francis Xavier Univ, Dept Comp Sci, Antigonish, NS B2G 2W5, Canada.;[Yi, Lingzhi] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Chen, Jiaoyan] Nanchang Univ, Sch Informat Engn, Nanchang 330031, Jiangxi, Peoples R China.;[Liu, Yong; Li, Xiangyang] Univ South China, Sch Resource Environm & Safety Engn, Hunan Prov Engn Res Ctr Radioact Control Technol, Hengyang 421001, Peoples R China.
通讯机构：
[Yi, Lingzhi] U;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
关键词：
Oceans;Learning automata;Surveillance;Sensors;Internet of Things;Peer-to-peer computing;Barrier coverage;confident information coverage (CIC) model;Internet of Things (IoT);learning automata (LA);smart ocean
摘要：
As an emerging network paradigm, the Internet of Things (IoT) which consists of a significant number of multifunctional and heterogeneous IoT nodes has attracted dramatic attentions from both academia and industry. With the merits of intelligent capacity, desirable scalability, and high reliability, the IoT recently has been applied for smart ocean applications to provide protection for ocean environment monitoring and surveillance. Aiming to provide coverage service for ocean border environmental surveillance, this article studies the barrier coverage problem which investigates how to select a collection of IoT nodes to obtain an IoT node chain and build barrier paths to detect intruders and trespassers crossing the border region of interest. To overcome the disadvantages in the existing works on barrier coverage, we adopt a novel and widely adopted confident information coverage (CIC) model as the fundamental coverage model and formulate the CIC barrier path construction (CICBC) problem with the goals of maximizing the number of barrier paths and minimizing the amount of IoT nodes in each barrier path. We propose a distributed CIC barrier path (CICBP) construction approach based on learning automata (CBLA). The CBLA includes four crucial phases which are initialization phase, learning phase, monitoring phase, and repairing phase. Each IoT node equips a learning automaton. CBLA selects an optimal IoT node to construct the barrier path by learning. The simulation results show that the performance of the CBLA algorithm outperforms two peer algorithms in terms of the number of barrier paths and the average number of nodes in each barrier path.
摘要：
Numerous lung nodule candidates can be produced through an automated lung nodule detection system. Classifying these candidates to reduce false positives is an important step in the detection process. The objective during this paper is to predict real nodules from a large number of pulmonary nodule candidates. Facing the challenge of the classification task, we propose a novel 3D convolution neural network (CNN) to reduce false positives in lung nodule detection. The novel 3D CNN includes embedded multiple branches in its structure. Each branch processes a feature map from a layer with different depths. All of these branches are cascaded at their ends; thus, features from different depth layers are combined to predict the categories of candidates. The proposed method obtains a competitive score in lung nodule candidate classification on LUNA16 dataset with an accuracy of 0.9783, a sensitivity of 0.8771, a precision of 0.9426, and a specificity of 0.9925. Moreover, a good performance on the competition performance metric (CPM) is also obtained with a score of 0.830. As a 3D CNN, the proposed model can learn complete and three-dimensional discriminative information about nodules and non-nodules to avoid some misidentification problems caused due to lack of spatial correlation information extracted from traditional methods or 2D networks. As an embedded multi-branch structure, the model is also more effective in recognizing the nodules of various shapes and sizes. As a result, the proposed method gains a competitive score on the false positive reduction in lung nodule detection and can be used as a reference for classifying nodule candidates.
摘要：
To solve the complexity of the traditional motion intention recognition method using a multi-mode sensor signal and the lag of the recognition process, in this paper, an inertial sensor-based motion intention recognition method for a soft exoskeleton is proposed. Compared with traditional motion recognition, in addition to the classic five kinds of terrain, the recognition of transformed terrain is also added. In the mode acquisition, the sensors' data in the thigh and calf in different motion modes are collected. After a series of data preprocessing, such as data filtering and normalization, the sliding window is used to enhance the data, so that each frame of inertial measurement unit (IMU) data keeps the last half of the previous frame's historical information. Finally, we designed a deep convolution neural network which can learn to extract discriminant features from temporal gait period to classify different terrain. The experimental results show that the proposed method can recognize the pose of the soft exoskeleton in different terrain, including walking on flat ground, going up and downstairs, and up and down slopes. The recognition accuracy rate can reach 97.64%. In addition, the recognition delay of the conversion pattern, which is converted between the five modes, only accounts for 23.97% of a gait cycle. Finally, the oxygen consumption was measured by the wearable metabolic system (COSMED K5, The Metabolic Company, Rome, Italy), and compared with that without an identification method; the net metabolism was reduced by 5.79%. The method in this paper can greatly improve the control performance of the flexible lower extremity exoskeleton system and realize the natural and seamless state switching of the exoskeleton between multiple motion modes according to the human motion intention.
摘要：
Bipolar host material and thermally activated delayed fluorescent (TADF) emitter were used in hybrid white organic light-emitting diodes (OLEDs) with the aim to achieve high performance. First of all, the single color OLEDs was optimized by changing the thickness of hole transporting layer, electron transporting layer and the doping concentration of emission material. Then, white organic light-emitting diodes (WOLEDs) were fabricated on the basis of the former single color OLEDs by modifying the doping concentration of TADF emitter. Finally, an optimized white device shows the best results of 43.67 cd/A, 45.73 lm/W and 18.52% for current efficiency, power efficiency and external quantum efficiency, respectively. This research may supply a theoretical basis for the development of WOLEDs.
