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基于FFT预处理与ASPeCT高阶BOC捕获优化算法研究
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作者 王海汇 叶红军 《计算机测量与控制》 2026年第2期211-218,226,共9页
针对二进制偏移载波(BOC)信号在高阶调制下因自相关函数副峰密集,副峰幅值高而导致的严重的捕获模糊问题,提出一种基于FFT均值预处理与ASPeCT算法相融合的联合捕获优化系统,构建一种创新的“预处理-捕获”协同处理框架,该框架通过FFT均... 针对二进制偏移载波(BOC)信号在高阶调制下因自相关函数副峰密集,副峰幅值高而导致的严重的捕获模糊问题,提出一种基于FFT均值预处理与ASPeCT算法相融合的联合捕获优化系统,构建一种创新的“预处理-捕获”协同处理框架,该框架通过FFT均值预处理,不仅显著降低了运算复杂度,更关键的是从频域层面抑制了高阶BOC信号所特有的密集副峰分量,从根本上优化了ASPeCT算法的输入信号质量,突破了传统方法固定加权系数难以适配高阶调制副峰结构的固有局限;仿真结果表明:该系统能实现BOC(14,2)等高阶信号的无模糊捕获,在-62~-5 dB的关键信噪比区间,达到相同检测概率与传统ASPeCT算法所需信噪比降低2~3 dB,同时捕获效率提升约35%;该研究系统性地解决了传统ASPeCT算法对高阶BOC信号捕获适配性瓶颈,为现代导航系统的可靠捕获提供了技术支撑。 展开更多
关键词 高阶BOC信号 无模糊捕获 aspect算法 副峰抑制 捕获性能
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Environmental and Psycho-social Factors Related to Prostate Cancer Risk in the Chinese Population:a Case-control Study 被引量:5
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作者 LI Mei Ling LIN Ji +11 位作者 HOU Jian Guo XU Lei CUI Xin Gang XU Xing Xing YU Yong Wei HAN Xue WANG Guo Min GUO Jian Ming XU Dan Feng THOMPSON Timothy C CAO Guang Wen ZHANG Hong Wei 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2014年第9期707-717,共11页
Objective To study the risk environmental and psycho-social factors associated to prostate cancer (PCa) in Chinese population. Methods 250 PCa patients and 500 controls were enrolled in this case-control study. Info... Objective To study the risk environmental and psycho-social factors associated to prostate cancer (PCa) in Chinese population. Methods 250 PCa patients and 500 controls were enrolled in this case-control study. Information was collected and logistic regression analysis was used to estimate the odds ratios (OR) and 95% confidence intervals (95% CI) for relationship between lifestyle, eating habits and psycho-social factors with PCa risk. Results Green vegetables and green tea were associated with a decreased risk of PCa (0R=0.39, 95% CI: 0.28-0.53; 0R=0.59, 95% Cl: 0.40-0.87, respectively). Family history of PCa (0R=7.16, 95% CI: 2.01-25.49), history of prostate diseases (0R=2.28, 95% Cl: 1.53-3.41), alcohol consumption (0R=1.97, 95% CI: 1.33-2.90), red meat consumption (0R=1.74, 95% CI: 1.20-2.52), barbecued (0R=2.29, 95% CI: 1.11-4.73) or fried (0R=2.35, 95% CI: 1.24-4.43) foods were related with increased PCa risk. Negative psycho-social factors including occupational setbacks (0R=1.61, 95% CI: 2.00-2.59), marital separation (0R=1.94, 95% CI: 1.29-2.91), self-contained suffering {0R=2.37, 95% CI: 1.58-3.55), and high sensitivity to the personal comments (0R=1.73, 95% CI: 1.18-2.54) were related to PCa. Conclusion Regular consumption of green vegetables and green tea may suggest protective effects on PCa. Alcohol consumption, red meat consumption and barbecued or fried foods were associated with PCa. Negative psycho-social factors may also play a role in the incidence of PCa in Chinese population. 展开更多
关键词 Case-control study LIFESTYLE Dietary factors psycho-social factors Prostate cancer
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Simple pain measures reveal psycho-social pathology in patients with Crohn's disease
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作者 Shmuel Odes Michael Friger +8 位作者 Ruslan Sergienko Doron Schwartz Orly Sarid Vered Slonim-Nevo Terri Singer Elena Chernin Hillel Vardi Dan Greenberg Israel IBD Research Nucleus 《World Journal of Gastroenterology》 SCIE CAS 2017年第6期1076-1089,共14页
To determine whether pain has psycho-social associations in adult Crohn’s disease (CD) patients.METHODSPatients completed demographics, disease status, Patient Harvey-Bradshaw Index (P-HBI), Short Form Health Survey ... To determine whether pain has psycho-social associations in adult Crohn’s disease (CD) patients.METHODSPatients completed demographics, disease status, Patient Harvey-Bradshaw Index (P-HBI), Short Form Health Survey (SF-36), Short Inflammatory Bowel Disease Questionnaire (SIBDQ), and five socio-psychological questionnaires: Brief Symptom Inventory, Brief COPE Inventory, Family Assessment Device, Satisfaction with Life Scale, and Work Productivity and Activity Impairment Questionnaire. Pain sub-scales in P-HBI, SF-36 and SIBDQ measures were recoded into 4 identical scores for univariate and multinomial logistic regression analysis of associations with psycho-social variables.RESULTSThe cohort comprised 594 patients, mean age 38.6 ± 14.8 years, women 52.5%, P-HBI 5.76 ± 5.15. P-HBI, SF-36 and SIBDQ broadly agreed in their assessment of pain intensity. More severe pain was significantly associated with female gender, low socio-economic status, unemployment, Israeli birth and smoking. Higher pain scores correlated positively with psychological stress, dysfunctional coping strategies, poor family relationships, absenteeism, presenteeism, productivity loss and activity impairment and all WPAI sub-scores. Patients exhibiting greater satisfaction with life had less pain. The regression showed increasing odds ratios for psychological stress (lowest 2.26, highest 12.17) and female gender (highest 3.19) with increasing pain. Internet-recruited patients were sicker and differed from hardcopy questionnaire patients in their associations with pain.CONCLUSIONPain measures in P-HBI, SF-36 and SIBDQ correlate with psycho-social pathology in CD. Physicians should be aware also of these relationships in approaching CD patients with pain. 展开更多
关键词 Crohn’s disease psycho-social pathology PAIN
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自动化ASPECTS评估急性缺血性脑卒中的人机对比研究
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作者 许萍 程晓青 +6 位作者 周长圣 田冰 田霞 石峰 曹泽红 高敏 邢伟 《医学研究与战创伤救治》 北大核心 2025年第4期370-375,共6页
目的探讨自动化Alberta卒中项目早期CT评分(ASPECTS)与专家评分的相关性、一致性,并比较两者预测良好临床预后的效能。方法回顾性分析2015年5月至2022年1月在苏州大学附属第三医院、东部战区总医院、上海长海医院绿色卒中通道的急性缺... 目的探讨自动化Alberta卒中项目早期CT评分(ASPECTS)与专家评分的相关性、一致性,并比较两者预测良好临床预后的效能。方法回顾性分析2015年5月至2022年1月在苏州大学附属第三医院、东部战区总医院、上海长海医院绿色卒中通道的急性缺血性脑卒中患者的临床资料。收集所有患者的入院平扫CT图像以及临床资料,自动化ASPECTS软件与神经放射学专家对平扫CT图像进行回顾性ASPECTS评估。Spearman分析自动化ASPECTS与专家评分的相关性,组内相关系数(ICC)用于评估一致性,受试者工作特性(ROC)曲线和DeLong检验评估和比较两者预测良好临床预后的效能。结果自动化ASPECTS与专家评分呈显著正相关(r=0.459,P<0.05),两者一致性较好(ICC=0.620)。自动化ASPECTS预测良好临床预后特异度高于专家(62.1%vs 41.1%),但灵敏度略低于专家(57.6%vs 73.7%),ROC曲线下面积均为0.605,DeLong检验两者差异无统计学意义(P=0.984)。结论自动化ASPECTS与专家评分呈显著正相关,两者间一致性好。在预测良好临床预后方面,两者评估效能相当。 展开更多
关键词 自动化Alberta卒中项目早期CT评分 急性缺血性脑卒中 计算机体层成像
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Phase field modeling of the aspect ratio dependent functional properties of NiTi shape memory alloys with different grain sizes 被引量:1
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作者 Bo Xu Beihai Huang +1 位作者 Chong Wang Qingyuan Wang 《Acta Mechanica Sinica》 2025年第1期22-41,共20页
It is well known that coarse-grained super-elastic NiTi shape memory alloys(SMAs)exhibit localized rather than homogeneous martensite transformation(MT),which,however,can be strongly influenced by either internal size... It is well known that coarse-grained super-elastic NiTi shape memory alloys(SMAs)exhibit localized rather than homogeneous martensite transformation(MT),which,however,can be strongly influenced by either internal size(grain size,GS)or the external size(geometric size).The coupled effect of GS and geometric size on the functional properties has not been clearly understood yet.In this work,the super-elasticity,one-way,and stress-assisted two-way shape memory effects of the polycrystalline NiTi SMAs with different aspect ratios(length/width for the gauge section)and different GSs are investigated based on the phase field method.The coupled effect of the aspect ratio and GS on the functional properties is adequately revealed.The simulated results indicate that when the aspect ratio is lower than about 4:1,the stress biaxiality and stress heterogeneity in the gauge section of the sample become more and more obvious with decreasing the aspect ratio,which can significantly influence the microstructure evolution in the process involving external stress.Therefore,the corresponding functional property is strongly dependent on the aspect ratio.With decreasing the GS and the aspect ratio(to be lower than 4:1),both the aspect ratio and GS can affect the MT or martensite reorientation in each grain and the interaction among grains.Thus,due to the strong internal constraint(i.e.,the constraint of grain boundary)and the external constraint(i.e.,the constraint of geometric boundary),the capabilities of the functional properties of NiTi SMAs are gradually weakened and highly dependent on these two factors. 展开更多
关键词 Phase field modeling NITI aspect ratio Grain size Functional property
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急性基底动脉闭塞性卒中PC-ASPECTS评分与PMT评分的一致性比较
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作者 柯烨 何野 +1 位作者 石冉 王朋 《安徽医专学报》 2025年第1期28-31,共4页
目的:评估急性基底动脉闭塞性卒中患者基于头颅磁共振(MRI)的后循环阿尔伯塔卒中计划早期计算机断层扫描评分(PC-ASPECTS)及脑桥中脑-丘脑评分(PMT)等影像学评分的一致性。方法:前瞻性纳入32例急性基底动脉闭塞性卒中患者。由12名临床... 目的:评估急性基底动脉闭塞性卒中患者基于头颅磁共振(MRI)的后循环阿尔伯塔卒中计划早期计算机断层扫描评分(PC-ASPECTS)及脑桥中脑-丘脑评分(PMT)等影像学评分的一致性。方法:前瞻性纳入32例急性基底动脉闭塞性卒中患者。由12名临床医师对MRI进行评分,评分数据用于最后的一致性分析,即总体一致性及二分法后的一致性。结果:二分法前,基于MRI的PC-ASPECTS评分与PMT评分的总体组间一致性均达到了良好的水平(κ=0.791[95%CI,0.732-0.843];κ=0.684[95%CI,0.603-0.724])。在二分法后,PC-ASPECTS评分总体医师的组间一致性达到了优秀的水平(κ=0.824[95%CI,0.738-0.912]);而PMT评分的总体医师的组间一致性仍然处于良好的水平(κ=0.769[95%CI,0.693-0.859])。结论:相比于PMT评分,临床医生在评估基于MRI的PCASPECTS评分时,在给予一定的容差范畴的情况下,其一致性的值更高,足以支持可重复的临床决策和评估。 展开更多
关键词 脑卒中 一致性 PC-aspectS评分 PMT评分
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Detecting Drowsiness Behind the Wheel: A Lightweight Approach Based on Eye and Mouth Aspect Ratios
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作者 Heyang Ni 《Journal of Electronic Research and Application》 2025年第4期30-38,共9页
Driver distraction is a leading cause of traffic accidents,with fatigue being a significant contributor.This paper introduces a novel method for detecting driver distraction by analyzing facial features using machine ... Driver distraction is a leading cause of traffic accidents,with fatigue being a significant contributor.This paper introduces a novel method for detecting driver distraction by analyzing facial features using machine deep learning and 68 face model.The proposed system assesses driver tiredness by measuring the distance between key facial landmarks,such as the distance between the eyes and the angle of the mouth,to evaluate signs of drowsiness or disengagement.Real-time video feed analysis allows for continuous monitoring of the driver’s face,enabling the system to detect behavioral cues associated with distraction,such as eye closures or changes in facial expressions.The effectiveness of this method is demonstrated through a series of experiments on a dataset of driver videos,which proves that the approach can accurately assess tiredness and distraction levels under various driving conditions.By focusing on facial landmarks,the system is computationally efficient and capable of operating in real-time,making it a practical solution for in-vehicle safety systems.This paper discusses the system’s performance,limitations,and potential for future enhancements,including integration with other in-vehicle technologies to provide comprehensive driver monitoring. 展开更多
关键词 Driver drowsiness detection Eye aspect ratio(EAR) Mouth aspect ratio(MAR) Facial landmark detection Real-time monitoring
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Correlation between prognostic markers and clinical parameters in hepatocellular carcinoma:Pathophysiological aspects to therapeutic targets
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作者 Saira Rafaqat Iqra Noshair +3 位作者 Momina Shahid Sadaf Bibi Ramsha Hafeez Hafsa Hamid 《World Journal of Gastrointestinal Oncology》 2025年第5期9-26,共18页
One of the main causes of cancer-related morbidity and mortality globally is hepatocellular carcinoma(HCC).At every stage of the disease,HCC may now be treated using a variety of therapy techniques.Nevertheless,despit... One of the main causes of cancer-related morbidity and mortality globally is hepatocellular carcinoma(HCC).At every stage of the disease,HCC may now be treated using a variety of therapy techniques.Nevertheless,despite the abundance of effective therapeutic choices,the prognosis for patients with HCC is still typically dismal.Prognostic indicators are crucial when assessing prognosis and tracking tumor metastases or recurrence.There are many prognostic markers in HCC.We mainly focused on newly reported prognostic markers such as MEX3A,apolipoprotein B,alpha-fetoprotein,circulating tumor cells,SAMD13,Agrin,and Glypican-3 in the pathogenesis of HCC.Further,we highlighted how these prognostic markers correlated to clinical parameters such as tumor node metastasis,tumor diameter,differentiation,hepatocirrhosis,vascular invasion,and others in HCC.Therefore,identifying specific prognostic biomarkers of HCC helps to provide a great opportunity to improve the prognosis in patients with HCC and provide therapeutic targets. 展开更多
关键词 Hepatocellular carcinoma Clinical parameters Prognostic markers Pathophysiological aspects Therapeutic targets
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Consideration of Aspect Ratios on Flow Around Wall-mounted Square Cylinders
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作者 Ilker Goktepeli 《哈尔滨工程大学学报(英文版)》 2025年第3期492-502,共11页
Flow characteristics around a wall-mounted square cylinder have been numerically simulated at aspect ratios (AR) ranging from 4 to 7 at Re =10 000. Four turbulence models have been compared in terms of drag coefficien... Flow characteristics around a wall-mounted square cylinder have been numerically simulated at aspect ratios (AR) ranging from 4 to 7 at Re =10 000. Four turbulence models have been compared in terms of drag coefficient (C_D). The closest result has been provided by two turbulence models, namely, k-ε Realizable and k ?ω Shear Stress Transport (SST). Hence, these models were utilized to present the flow patterns of pressure distributions, turbulent kinetic energy values, velocity magnitude values with streamlines, streamwise velocity components, crossstream velocity components and spanwise velocity components on different planes. Flow stagnation has been attained in front of the cylinder. Pressure values peaked for the upstream region. Over the cylinders, the tip vortex structure was dominant owing to the influence of the free end. Flow separation from the top front edge of the body has been obtained. The dividing streamline affected by the flow separation was highly effective in the wake region and moved nearer to the body when the aspect ratio was decreased;the reason was the wake shrinkage owing to the decreasing aspect ratio. Upwash and downwash have been seen in the cylinder wake. These two models presented similar flow patterns and drag coefficients. These drag coefficients are in good agreement with those in previous studies. 展开更多
关键词 aspect ratio Drag coefficient Reynolds number Turbulence model Wall-mounted square cylinder
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Effect of the Aspect Ratio of Box Girders on the Buffeting Response of Long-Span Suspension Bridges
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作者 Jingxiang Zhou Qiaoling Zhou +3 位作者 Chunlian Liang Yulu Guo Zhao Xiao Yingfeng Xu 《Structural Durability & Health Monitoring》 2025年第4期953-983,共31页
Streamlined box girders serve as a prevalent choice for the primary structural elements in large-span suspension bridge designs.With the increase in traffic demands,the design of such girders is evolving towards wider... Streamlined box girders serve as a prevalent choice for the primary structural elements in large-span suspension bridge designs.With the increase in traffic demands,the design of such girders is evolving towards wider bridge decks and larger aspect ratios(B/D).To obtain more effective and aerodynamic design shapes for streamlined box girders,it is essential to investigate the impact of B/D on their aerodynamic performance.Accordingly,in this study we investigate the buffeting responses of large-span suspension bridges using girders of varying aspect ratios(B/D of 7.5,9.3,and 12.7).First,the aerodynamic coefficients of these girders are estimated using computational fluid dynamics(CFD)simulations.Subsequently,spatial finite element(FE)models of three long-span suspension bridges with different girders(B/D of 7.5,9.3,and 12.7)are established in Ansys software,and the dynamic characteristics of these bridges are obtained.Then,the time-domain buffeting analysis is performed by simulating the fluctuating wind fields acting on the bridge through the spectral representation method.Ultimately,the buffeting responses are computed using Ansys software,and the impact of B/D on these responses is assessed.The results reveal that the root mean square(RMS)values of the main girder’s buffeting displacement are highest at the midspan position and are lowest at the ends of the bridge.A decrease in B/D of the main girder leads to a more severe buffeting response because both the range and the effective value of the displacement increase with the decreasing B/D.Comparing the buffeting displacements in three directions,B/D plays a significant role in the vertical buffeting displacement,moderately impacts the torsional displacement,and has the least effect on the lateral displacement.The findings of this study may help wind resistance analysis and design optimization for bridges. 展开更多
关键词 Long-span suspension bridge buffeting response aspect ratio streamlined box girder turbulent flow
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Pressure oscillation and suppression method of large-aspect-ratio solid rocket motors
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作者 Yunzhi XI Jingwei GAO +3 位作者 Zeping WU Bolun ZHANG Lijun YANG Jun XIA 《Chinese Journal of Aeronautics》 2025年第4期10-24,共15页
A two-dimensional large eddy simulation numerical model is proposed to study the transient vortex flow and pressure oscillation of a large-aspect-ratio solid rocket motor.The numerical model is validated through exper... A two-dimensional large eddy simulation numerical model is proposed to study the transient vortex flow and pressure oscillation of a large-aspect-ratio solid rocket motor.The numerical model is validated through experimental data,finite element analysis and cumulative error analysis.The numerical simulations are executed to obtain the characteristics of the vortex-acoustic and pressure oscillation.The results show that the burning surface regression decreases the motor aspect ratio,increasing the corresponding natural frequency from 260 Hz to 293 Hz.The pressure oscillation phenomenon is formed due to the vortex-acoustic coupling.Decreasing the corner vortex shedding intensity shows negative effects on the dimensionless amplitude of the pressure oscillation.The head cavity without the injection can decrease the vortex-acoustic coupling level at the acoustic pressure antinode.The modified motor with head cavity can obtain a lower dimensionless oscillating pressure amplitude 0.00149 in comparison with 0.00895 of the original motor.The aspect ratio and volume of the head cavity without the injection have great effects on the pressure oscillation suppression,particularly at the low aspect ratio or large volume.The reason is that the mass in the region around the acoustic pressure antinode is extracted centrally,reducing the energy contribution to the acoustic system.With the volume increasing,the acoustic energy capacity increases. 展开更多
关键词 Pressure oscillation Suppression method Solid rocket motor Large aspect ratio Large eddy simulation
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High voltage cathode materials for rechargeable magnesium batteries:Structural aspects and electrochemical perspectives
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作者 Dedy Setiawan Jiwon Hwang +1 位作者 Munseok S.Chae Seung-Tae Hong 《Journal of Magnesium and Alloys》 2025年第9期4167-4188,共22页
Rechargeable magnesium batteries(RMBs)are a cutting-edge energy storage solution,with several advantages over the state-of-art lithiumion batteries(LIBs).The use of magnesium(Mg)metal as an anode material provides a m... Rechargeable magnesium batteries(RMBs)are a cutting-edge energy storage solution,with several advantages over the state-of-art lithiumion batteries(LIBs).The use of magnesium(Mg)metal as an anode material provides a much higher gravimetric capacity compared to graphite,which is currently used as the anode material in LIBs.Despite the significant advances in electrolyte,the development of cathode material is limited to materials that operate at low average discharge voltage(<1.0 V vs.Mg/Mg^(2+)),and developing high voltage cathodes remains challenging.Only a few materials have been shown to intercalate Mg^(2+)ions reversibly at high voltage.This review focuses on the structural aspects of cathode material that can operate at high voltage,including the Mg^(2+)intercalation mechanism in relation to its electrochemical properties.The materials are categorized into transition metal oxides and polyanions and subcategorized by the intrinsic Mg^(2+)diffusion path.This review also provides insights into the future development of each material,aiming to stimulate and guide researchers working in this field towards further advancements in high voltage cathodes. 展开更多
关键词 gravimetric capacity cathode material energy storage high voltage cathode materials anode material structural aspects lithiumion batteries libs rechargeable magnesium batteries
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Aspect-Level Sentiment Analysis of Bi-Graph Convolutional Networks Based on Enhanced Syntactic Structural Information
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作者 Junpeng Hu Yegang Li 《Journal of Computer and Communications》 2025年第1期72-89,共18页
Aspect-oriented sentiment analysis is a meticulous sentiment analysis task that aims to analyse the sentiment polarity of specific aspects. Most of the current research builds graph convolutional networks based on dep... Aspect-oriented sentiment analysis is a meticulous sentiment analysis task that aims to analyse the sentiment polarity of specific aspects. Most of the current research builds graph convolutional networks based on dependent syntactic trees, which improves the classification performance of the models to some extent. However, the technical limitations of dependent syntactic trees can introduce considerable noise into the model. Meanwhile, it is difficult for a single graph convolutional network to aggregate both semantic and syntactic structural information of nodes, which affects the final sentence classification. To cope with the above problems, this paper proposes a bi-channel graph convolutional network model. The model introduces a phrase structure tree and transforms it into a hierarchical phrase matrix. The adjacency matrix of the dependent syntactic tree and the hierarchical phrase matrix are combined as the initial matrix of the graph convolutional network to enhance the syntactic information. The semantic information feature representations of the sentences are obtained by the graph convolutional network with a multi-head attention mechanism and fused to achieve complementary learning of dual-channel features. Experimental results show that the model performs well and improves the accuracy of sentiment classification on three public benchmark datasets, namely Rest14, Lap14 and Twitter. 展开更多
关键词 aspect-Level Sentiment Analysis Sentiment Knowledge Multi-Head Attention Mechanism Graph Convolutional Networks
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基于28 nm CMOS技术平台的STI无接缝填充工艺研究
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作者 刘聪 李华曜 +1 位作者 张欢欢 刘欢 《功能材料与器件学报》 2026年第1期105-112,共8页
本文针对28 nm互补金属-氧化物-半导体(complementary metal-oxide-semiconductor,CMOS)工艺中高深宽比、非标准V形浅沟槽隔离(shallow trench isolation,STI)结构所面临的填充挑战展开研究。该结构易在填充后中心形成接缝,影响器件隔... 本文针对28 nm互补金属-氧化物-半导体(complementary metal-oxide-semiconductor,CMOS)工艺中高深宽比、非标准V形浅沟槽隔离(shallow trench isolation,STI)结构所面临的填充挑战展开研究。该结构易在填充后中心形成接缝,影响器件隔离可靠性。为此,本研究提出采用高深宽比工艺(high aspect ratio process,HARP)沉积与后蒸汽高温退火相结合的方案,旨在实现无接缝填充。本研究通过交叉实验,系统分析新型HARP沉积与创新高温退火工艺对氧化硅薄膜收缩率及沟槽接缝形貌的影响。实验结果表明,仅依靠单一工艺优化无法完全消除V形结构底部的微缝。最终的解决方案强调工艺协同:将新型HARP沉积与脉冲式高温退火相结合,并在退火过程中引入氯化氢(HCl)作为辅助气体。该协同工艺可精确调控薄膜的致密化过程,并利用HCl的气相刻蚀作用有效清除界面薄弱区,从而在高深宽比、非标准V形STI结构内实现高质量的无接缝填充。本研究为先进技术节点复杂三维结构的集成提供了有效的工艺路径。 展开更多
关键词 28 nm CMOS 高深宽比 沟槽填充 无接缝
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基于形状自适应标签分配的遥感有向目标检测网络
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作者 任王 吴斌 +1 位作者 余长宏 曾文捷 《电信科学》 北大核心 2026年第2期148-160,共13页
针对遥感图像中大纵横比目标因正样本不足而出现的学习不充分问题,提出一种基于形状自适应标签分配的遥感有向目标检测网络(shape-adaptive label assignment for oriented object detection network,SALANet)。首先,引入纵横比敏感系... 针对遥感图像中大纵横比目标因正样本不足而出现的学习不充分问题,提出一种基于形状自适应标签分配的遥感有向目标检测网络(shape-adaptive label assignment for oriented object detection network,SALANet)。首先,引入纵横比敏感系数建立目标几何特征与正样本数量的动态映射关系,缓解传统方法中固定分配规则引发的样本分布不平衡问题;其次,设计自适应标签分配策略,通过对交并比(intersection over union,IoU)进行排名实现高质量正样本选择;最后,提出中心轴先验,将圆形中心先验区扩展为目标中心轴的矩形区域,增强大纵横比目标的几何特征表征能力。在DOTAv1.0和HRSC2016数据集上的对比实验表明,SALANet分别取得0.777 1和0.932 3的平均精度均值(mean average precision,mAP),较基线方法RoI Transformer分别提升8.15%和2.87%。 展开更多
关键词 遥感图像 有向目标检测 大纵横比目标 形状自适应标签分配 中心轴先验
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基于级进延展冷镦工艺的大长径比薄壁管件成形优化
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作者 孙进 陈野 +1 位作者 朱兴龙 黄小建 《锻压技术》 北大核心 2026年第2期7-14,共8页
针对常见的大长径比薄壁管件热锻工艺存在的温度难以控制、尺寸精度低的问题,以长径比为5.3的气弹簧用油气缸为例,提出一种先镦粗后级进延展式冷镦成形方法。在搭建三维模型的基础上,利用Deform-3D软件对拟定工艺的金属流动规律、成形... 针对常见的大长径比薄壁管件热锻工艺存在的温度难以控制、尺寸精度低的问题,以长径比为5.3的气弹簧用油气缸为例,提出一种先镦粗后级进延展式冷镦成形方法。在搭建三维模型的基础上,利用Deform-3D软件对拟定工艺的金属流动规律、成形载荷和断裂趋势等进行分析,验证了工艺的可行性。结合仿真结果,以薄壁延伸最大成形载荷为优化目标,利用正交试验与极差分析,得出各因素对最大成形载荷的影响程度依次为:首次缩径值a>入模角λ>冲头下压速度v,并选取了最优工艺参数组合:冲头下压速度v=15 mm·s^(-1)、首次缩径值a=0.70 mm、入模角λ=7°。优化后的工艺参数使最大成形载荷降低了18.15%,提高了薄壁成形质量。研究结果为同类大长径比薄壁管件的研究提供了理论参考。 展开更多
关键词 大长径比薄壁管件 级进延展冷镦工艺 最大成形载荷 金属流动规律 损伤值
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基于提示学习和注意力机制的多模态方面级情感分析
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作者 曾桢 廖茂熙 +2 位作者 杨楠 罗燕 杨超 《科学技术与工程》 北大核心 2026年第2期708-716,共9页
针对现有多模态方面级情感分析模型存在不同模态之间关联性不强,难以有效利用它们之间相关信息的问题,提出了一种基于提示学习和注意力机制的多模态方面级情感分析模型。首先,在文本和图像特征分别输入多层Transformer层之前,对文本特... 针对现有多模态方面级情感分析模型存在不同模态之间关联性不强,难以有效利用它们之间相关信息的问题,提出了一种基于提示学习和注意力机制的多模态方面级情感分析模型。首先,在文本和图像特征分别输入多层Transformer层之前,对文本特征添加提示信息,并通过耦合函数投影到图像特征中;其次,使用跨模态注意力机制进行特征融合,并通过双向门控循环单元(bidirectional gated recurrent unit,BiGRU)过滤融合过程中的无关信息;然后,构建了一个由方面信息引导的注意力模块,以加强对方面信息的关注度;最后,通过全连接层和softmax分类层得到情感分类结果。该模型分别在公开的Twitter-15和Twitter-17数据集上进行实验,结果显示与多个基线模型相比,所提模型的准确率和F1均有所提升,证明了所提模型在多模态方面级情感分析任务中的有效性。 展开更多
关键词 方面级情感分析 多模态 提示学习 特征提取 注意力机制 自然语言处理
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