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Journal of Materials Science & Technology 2017年第10期33卷 1182-1186页

作者： Pengbo Li Tiehu Li hongxia Yan School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China Department of Applied Chemistry. School of Science Northwestern Polytechnical University. Xi'an 710072. China

Bismaleimide containing cyanate resin（BMI/CE） pre-ploymer was used as resin matrix. Fluorinated multiwalled carbon nanotubes（F-MWCNTs） were used as fillers to prepare F-MWCNT/BMI/CE nanocomposites via a solution intercalation method. The influence of F-MWCNT content on the mechanical, tribological and heat resistant properties of the nanocomposites was investigated. The morphology of the fracture surface and the wear surface of nanocomposites were characterized by scanning electron *** show that the addition of F-MWCNTs is beneficial to improving the mechanical and tribological properties of the nanocomposites. It＇s worth noting that when the content of F-MWNTs was 0.6 wt%, the performances of nanocomposite are optimized（i.e., highest impact strength, lowest frictional coefficient and wear rate）. In addition, the nanocomposites exhibit good thermal stability in comparison with BMI/CE.

关键词： Carbon nanotubes Nanocomposites Mechanical property Tribological properties Thermal stability

Semi-supervised Artificial Immune Mixture Models Clustering

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Chinese Journal of Electronics 2016年第2期25卷 249-255页

作者： HUANG Wenlong WANG xiaodan LI Guohong KANG hongxia Air and Missile Defense College Air Force Engineering University State Key Laboratory of Astronautic Dynamics Xi'an Satellite Control Center

Learning with partly labeled data aims at combining labeled and unlabeled data in order to boost the accuracy of an algorithm. The traditional Expectation maximization(EM) algorithm only produces locally optimal solutions, it is sensitive to initialization, and the number of components of mixture model must be known in advance. We propose a novel semi-supervised clustering algorithm that uses Gaussian mixture models(GMM) as the underlying clustering model. A novel adaptive global search mechanism is introduced into semi-supervised gaussian mixture model-based clustering, where the EM algorithm is incorporated with the ideas of an immune clonal selection technique. The new algorithm overcomes the various problems associated with the traditional EM algorithm. And it can improve the effectiveness in estimating the parameters and determining the optimal number of clusters automatically. The experimental results illustrate the proposed algorithm provides significantly better clustering results, when compared with other methods of incorporating equivalence constraints.

关键词： Semi-supervised clustering Mixture model Immune clonal selection Globally optimal solution

Tea polyphenols increase X-ray repair cross-complementing protein 1 and apurinic/apyrimidinic endonuclease/redox factor-1 expression in the hippocampus of rats during cerebral ischemia/reperfusion injury

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Neural Regeneration Research 2012年第30期7卷 2355-2361页

作者： Zhi Wang Rongliang Xue xi Lei Jianrui Lv Gang Wu Wei Li Li Xue xiaoming Lei hongxia Zhao Hui Gao xin Wei Department of Anesthesiology Second Affiliated Hospital of Medical College Xi'an Jiaotong University Xi'an 710004 Shaanxi Province China Department of Anesthesiology Stomatological Hospital Xi'an Jiaotong University Xi'an 710004 Shaanxi Province China

Recent studies have shown that tea polyphenols can cross the blood-brain barrier, inhibit apoptosis and play a neuroprotective role against cerebral ischemia. Furthermore, tea polyphenols can decrease DNA damage caused by free radicals. We hypothesized that tea polyphenols repair DNA damage and inhibit neuronal apoptosis during global cerebral ischemia/reperfusion. To test this hypothesis, we employed a rat model of global cerebral ischemia/reperfusion. We demonstrated that intraperitoneal injection of tea polyphenols immediately after reperfusion significantly reduced apoptosis in the hippocampal CA1 region; this effect started 6 hours following reperfusion. Immunohistochemical staining showed that tea polyphenols could reverse the ischemia/reperfusion-induced reduction in the expression of DNA repair proteins, X-ray repair cross-complementing protein 1 and apudnic/apyrimidinic endonuclease/redox factor-1 starting at 2 hours. Both effects lasted at least 72 hours. These experimental findings suggest that tea polyphenols promote DNA damage repair and protect against apoptosis in the brain.

关键词： global cerebral ischemia/reperfusion X-ray repair cross-complementing protein 1 apurinic/apyrimidinic endonuclease/redox factor-I tea polyphenols

Performance investigations of novel dual-material gate(DMG) MOSFET with dielectric pockets(DP)

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Science China(Technological Sciences) 2009年第8期52卷 2400-2405页

作者： LUAN SuZhen LIU hongxia JIA RenXu Key Laboratory of Ministry of Education of China for Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian UniversityXi’an 710071China

Dual-material gate MOSFET with dielectric pockets (DMGDP MOSFET) is proposed to eliminate the potential weakness of the DP MOSFET for CMOS scaling toward the 32 nm gate length and beyond. The short-channel effects (SCE) can be effectively suppressed by the insulator near the source/drain regions. And the suppression capability can be even better than the DP MOSFET due to the drain bias absorbed by the screen gate. The speed performance and electronic characteristics of the DMGDP MOSFET are comprehensively studied. Compared to the experimental data from Jurczak et al., the DMGDP PMOSFET exhibits good subthreshold characteristics and the on-state current is almost the twice that of the DP PMOSFET. The intrinsic delay of the NMOS reaches 21% greater than the DP MOSFET for 32 nm node. The higher fT of 390 GHz is achieved, which is a 32% enhancement in comparison with the DP MOSFET when the gate length is 50 nm. Finally, the design guideline and the optimal regions of the DMGDP MOSFET are discussed.

关键词： dual material gate (DMG) dielectric pockets (DP) short-channel effect (SCE) cutoff frequency

Performance Improvement of Two-Phase Steam Ejector based on CFD Techniques,Response Surface Methodology and Genetic Algorithm

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Journal of Thermal Science 2024年第2期33卷 675-695页

作者： ZHANG Hao ZHAO hongxia ZHANG xiuao ZENG Hongxuan DENG Jianqiang School of Energy and Power Engineering Shandong UniversityJi’nan250061China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an710049China

The steam ejector is a crucial component in the waste heat recovery *** performance determines the amount of recovered heat and system ***,poor ejector performance has always been the main bottleneck for system ***,this study proposes an optimization methodology to improve the steam ejector's performance by utilizing computational fluid dynamics(CFD) techniques,response surface methodology(RSM),and genetic algorithm(GA).Firstly,a homogeneous equilibrium model(HEM) was established to simulate the two-phase flow in the steam ***,the orthogonal test was presented to the screening of the key decision variables that have a significant impact on the entrainment ratio(ER).Next,the RSM was used to fit a response surface regression model(RSRM).Meanwhile,the effect of the interaction of geometric parameters on the performance of the steam ejector was ***,GA was employed to solve the RSRM's global optimal ER *** results show that the RSRM exhibits a good fit for ER(R^(2)=0.997).After RSM and GA optimization,the maximum ejector efficiency is 27.94%,which is 48.38% higher than the initial ejector of 18.83%.Furthermore,the optimized ejector efficiency is increased by 46.4% on average under off-design ***,the results reveal that the combination of CFD,RSM,and GA presents excellent reliability and feasibility in the optimization design of a two-phase steam ejector.

关键词： two-phase steam ejector optimization methodology CFD techniques response surface methodology genetic algorithm homogeneous equilibrium model

Multivariable Decoupling Control of Civil Turbofan Engines Based on Fully Actuated System Approach

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Journal of Systems Science & Complexity 2023年第3期36卷 947-959页

作者： PENG Kai WANG hongxia ZHANG Huanshui ZHANG Zhaorong YANG Fan School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China School of Electrical and Automation Engineering Shandong University of Science and TechnologyQingdao 266590China Department of Applied Mathematics The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina. xi’an Aeronautics Computing Technique Research Institute AVICXi’an 710068China

Gas turbine engines must be operated by means of control,and how to achieve multivariable control decoupling with aero-engine control constraints is an open thorny issue attracting increasingly more *** paper considers the multivariable decoupling problems of aero-engines by using a compound controller,which originates from the fact that it is impossible to eliminate all the nonlinear dynamics of system to obtain desired constant linear closed-loop system by using full actuated control because of modeling errors and some physical *** controllers are involved in the compound *** is a fully actuated controller and the other is classical feedback *** order to use fully actuated control and maintain the accuracy of engine model,a full state scheduling linear parameter-varying(LPV)modeling method is proposed based on fuzzy neural network *** a general input matrix of the system,its generalized inverse is applied to design fully actuated controller to result in a pseudolinear *** with a feedback controller and control limiter,the control synthesis is *** simulation shows that the proposed method is possessed of a better decoupling and tracking effect compared with traditional control approach.

关键词： Compound control decoupling control fully actuated control turbofan engine

Low-power design and application based on CSD optimization for a fixed coefficient multiplier

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Science China(Information Sciences) 2011年第11期54卷 2443-2453页

作者： LIU hongxia & YUAN Bo Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Devices,School of Microelectronics,xidian University,xi’an 710071,China Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Devices School of Microelectronics Xidian University Xi’an China

This paper presents a low-power design for a fixed coefficient multiplier,based on the canonic signed digit (CSD) *** proposed technology overcomes the defects of the general CSD method by reducing system power and area substantially without additional *** theoretical basis and a design method are explained in detail in this *** design technology was used to optimize a radio-frequency *** test results show that logic utilization is reduced by 25%,the total number of registers used is reduced by 23.02%,and the total block memory bits utilization is reduced by 20%.These results show that the proposed low-power design is an effective method.

关键词： canonic signed digit optimization coefficient of multiplication system power system area logic cell number FPGA test results

The ecological sequence of Hipparion fauna in the middle reaches of the Yellow River during Neogene

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Chinese Science Bulletin 2002年第1期47卷 79-82页

作者： ZHANG Yunxiang YUE Leping CAO hongxia The Key Laboratory of Northwest University Continental Dynamics Ministry of EducationChinaXi’an 7J0069China Institute of Earth Environment Chinese Academy of SciencesXi’an 710069China

The faunal ecological type and sequence in the Tertiary red clay indicate that Hipparion fauna during the period 7.4-6.1 Ma in the middle reaches of the Yellow River is composed mainly of dorcadoides and mixed types. This represents semiarid veld environment with small fluctuation. The fossil assemblages characterized by the abundance of gaudryi types and even the occurrence of some Hominoid and Chalicotherium indicate an obviously warm and humid period since 5.3 Ma. The fossil assemblages during 3.4 Ma show the typical steppe fauna representing dry climate. It is indicated by the changes of ecological sequence that the cli-matic conditions in Pliocene are drier than that in late Mio-cene. The clay-skin content of red clay, which has a syn-chronous change with faunal features, is a rather good re-placing palaeoclimatic index.

关键词： Neogene red clay Hipparion fauna environment evolution.

A novel model of photo-carrier screening effect on the GaN-based p-i-n ultraviolet detector

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Science China(Physics,Mechanics & Astronomy) 2010年第5期53卷 793-801页

作者： GAO Bo,LIU hongxia,KUANG QianWei,ZHOU Wen & CAO Lei School of Microelectronics,xidian University,Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices,xi’an 710071,China School of Microelectronics Xidian University Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices Xi’an China

The photo-carrier density in the depletion region of the GaN-based p-i-n ultraviolet(UV) detector is calculated by solving the photo-carrier continuity equation,and the photo-carrier screening electric field is calculated according to Poisson's *** the numerical calculation method,a novel model of photo-carrier screening effect is *** the influence of photo-carrier screening effect on the distribution of photo-carrier density in the depletion region of p-i-n detector is *** influence of incident power,bias voltage and carrier life time on the photo-carrier screening effect is also *** is concluded that the influence of photo-carrier screening effect on the performance of GaN-based p-i-n UV detector is non-monotone,the maximum of carrier drift velocity and the minimum of response time can be realized by adjusting the applied ***,the incident light duration has strong impact on the photo-carrier screening effect.

关键词： GaN p-i-n ultraviolet detector photo-carrier screening effect

A review of deep learning methods for pixel-level crack detection

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第6期9卷 945-968页

作者： hongxia Li Weixing Wang Mengfei Wang Limin Li Vivian Vimlund School of Information Engineering Chang'an UniversityXi'an 710064China School of Computer Baoji University of Arts and SciencesBaoji 721013China School of Electrical and Electronic Engineering Wenzhou UniversityWenzhou 325035China Department of Computer Science and Technology Linkoping UniversityLinköpingSweden

Cracks are a major sign of aging transportation *** detection and repair of cracks is the key to ensuring the overall safety of the transportation *** recent years,due to the remarkable success of deep learning(DL)in the field of crack detection,many researches have been devoted to developing pixel-level crack image segmentation(CIS)models based on DL to improve crack detection accuracy,but as far as we know there is no review of DL-based CIS methods *** address this gap,we present a comprehensive thematic survey of DL-based CIS *** review offers several contributions to the CIS ***,more than 40 papers of journal or top conference most published in the last three years are identified and collected based on the systematic literature review ***,according to the backbone network architecture of the models proposed in them,they are grouped into 10 topics:FCN,U-Net,encoder-decoder model,multi-scale,attention mechanism,transformer,two-stage detection,multi-modal fusion,unsupervised learning and weakly supervised learning,to be ***,our survey focuses on discussing strengths and limitations of the models in each topic so as to reveal the latest research progress in the CIS ***,publicly accessible data sets,evaluation metrics,and loss functions that can be used for pixel-level crack detection are systematically introduced and summarized to facilitate researchers to select suitable components according to their own research ***,we discuss six common problems and existing solutions to them in the field of DL-based CIS,and then suggest eight possible future research directions in this field.

关键词： Crack image segmentation Crack detection Convolutional neural networks Deep learning Systematic literature review