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NEAR-FIELD ACOUSTIC HOLOGRAPHY FOR SEMI-FREE ACOUSTIC FIELD BASED ON WAVE SUPERPOSITION APPROACH

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Chinese Journal of Mechanical Engineering 2006年第3期19卷 455-459页

作者： LI Weibing chen jian YU fei chen Xinzhao Institute of Sound and Vibration Research Hefei University of Technology Hefei 230009 China

In the semi-free acoustic field, the actual acoustic pressure at any point is composed of two parts： The direct acoustic pressure and the reflected acoustic pressure. The general acoustic holographic theories and algorithms request that there is only the direct acoustic pressure contained in the pressure at any point on the hologram surface, consequently, they cannot be used to reconstruct acoustic source and predict acoustic field directly. To take the reflected pressure into consideration, near-field acoustic holography for semi-free acoustic field based on wave superposition approach is proposed to realize the holographic reconstruction and prediction of the semi-free acoustic field, and the wave superposition approach is adopted as a holographic transform algorithm. The proposed theory and algorithm are realized and verified with a numerical example, and the drawbacks of the general theories and algorithms in the holographic reconstruction and prediction of the semi-free acoustic field are also demonstrated by this numerical example.

关键词： Near-field acoustical holography Semi-free acoustic field Wave superposition approach

内压作用下碳纤维增强复合材料内衬加固预应力钢筒混凝土管承载力分析

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工业建筑 2024年第6期54卷 61-71页

作者：张霄杰吴嘉瑜陈建飞哈尔滨工业大学航天学院哈尔滨150006 南方科技大学海洋科学与工程系广东深圳518055

在内压作用下,预应力钢筒混凝土管(PCCP)可能发生各结构层失效。在PCCP内壁粘贴碳纤维增强复合材料(CFRP)是常见的修复方法,然而修复PCCP在内压作用下的结构失效机理研究尚不成熟。鉴于此,建立了CFRP内衬加固PCCP在内压作用下的多层圆... 详细信息

在内压作用下,预应力钢筒混凝土管(PCCP)可能发生各结构层失效。在PCCP内壁粘贴碳纤维增强复合材料(CFRP)是常见的修复方法,然而修复PCCP在内压作用下的结构失效机理研究尚不成熟。鉴于此,建立了CFRP内衬加固PCCP在内压作用下的多层圆环模型(MRM)力学模型,推导得到了CFRP内衬加固PCCP在内压作用下管壁径向位移、应力和应变的表达式。该力学模型计算结果与已有试验结果吻合良好,验证了力学模型的正确性。参数分析结果表明:增加钢筒厚度和混凝土管芯厚度可提高PCCP的内压承载力,提升预应力水平可提高PCCP抗开裂能力,增加CFRP厚度可以提高CFRP内衬加固PCCP的内压承载力。

关键词：预应力钢筒混凝土管碳纤维增强复合材料多层圆环模型内压理论分析

基于自监督对比学习与方面级情感分析的联合微调模型

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科学技术与工程 2024年第21期24卷 9033-9042页

作者：狄广义陈见飞杨世军高军王耀坤余本功国能数智科技开发(北京)有限公司北京100011 合肥工业大学管理学院合肥230009

方面级情感分析是自然语言处理领域中一项具有挑战性的细粒度情感分析任务。以微调预训练语言模型的方式广泛应用于方面级情感分析任务,并取得了明显的效果提升。然而,现有多数研究设计的下游结构较为复杂,甚至与预训练模型部分隐藏层... 详细信息

方面级情感分析是自然语言处理领域中一项具有挑战性的细粒度情感分析任务。以微调预训练语言模型的方式广泛应用于方面级情感分析任务,并取得了明显的效果提升。然而,现有多数研究设计的下游结构较为复杂,甚至与预训练模型部分隐藏层结构重合,从而限制了整体模型性能。由于对比学习方法有助于改善预训练语言模型在词语级别和句子级别的表示,设计了一种结合自监督对比学习与方面级情感分析的联合微调模型(self-supervised contrastive learning aspect-based sentiment analysis,SSCL-ABSA)。该模型以简洁的下游结构联合两种学习任务,实现从不同角度微调预训练基于Transformer的双向编码器(bidirectional encoder representations from Transformers,BERT)模型,有效促进了方面级情感分析效果的提升。具体地,首先在BERT编码阶段,将评论文本与方面词拼接成两个片段输入BERT编码器,得到各词特征表示。之后根据下游结构需求,对不同的词特征采用池化操作。一方面池化所有词特征用于方面级情感分析,另一方面池化两个片段的方面词特征用于自监督对比学习。最终结合两种任务以联合学习的方式微调BERT编码器。在3个公开数据集上进行实验评估,结果表明SSCL-ABSA方法优于其他同类对比方法。借助t-分布随机近邻嵌入(t-distributed stochastic neighbor embedding,t-SNE)方法,形象地可视化了SSCL-ABSA有效改善了BERT模型的实体表示效果。

关键词：方面级情感分析自监督对比学习预训练语言模型 BERT编码器联合微调

Three-Rigid-Body-Particle Modeling and Optimization of Trajectory and Posture for Alpine Skiing

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Journal of Systems Science & Complexity 2024年第2期37卷 581-608页

作者： ZHANG Yijia fei Qing YAO Xiaolan SUN jian ZHANG Yanjun chen Zhen School of Automation Beijing Institute of TechnologyBeijing 100081China

This paper presents a new study on modeling and optimization of trajectory and posture for the super-giant(SG)slalom of alpine *** is the first time that a Three-Rigid-Body-Particle model based on rigorous derivations and stability analysis is established to represent skiers trajectory and posture characteristics,as it is more accurate than the single-rigid-body model which is commonly used in existing *** addition,the Radau pseudospectral method is applied to solve the trajectory and posture optimization problem in order to obtain better skiing trajectory,skiing posture,and some key kinematic parameters of ***,this paper analyzes the effects of different body types,minimum turning radii,and flexor and extensor strength of knees and hip joint on skiing ***,based on the findings of the study,some advice about how to improve the performance of the SG slalom in view of science and technology is given to skiers and coaches for reference.

关键词： Alpine skiing modeling posture optimization Three-Rigid-Body-Particle model trajectory optimization

烧山火针刺法联合甲氨蝶呤治疗类风湿关节炎活动期的效果及其对患者炎症因子和免疫功能的影响

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海南医学 2024年第2期35卷 200-205页

作者：陈建飞武慧群李凌鑫罗伟贤任连军郑州市第一人民医院中医科河南郑州450000 内蒙古科技大学包头医学院第一附属医院康复医学科内蒙古包头014010 四川大学华西医院康复医学科四川成都610044

目的观察烧山火针刺法联合甲氨蝶呤治疗类风湿关节炎(RA)活动期的效果,并探讨其抗炎和调节免疫作用机制。方法选取2020年2月至2022年10月郑州市第一人民医院收治的60例RA活动期患者纳入研究,按照随机数表法分为常规组和联合组各30例... 详细信息

目的观察烧山火针刺法联合甲氨蝶呤治疗类风湿关节炎(RA)活动期的效果,并探讨其抗炎和调节免疫作用机制。方法选取2020年2月至2022年10月郑州市第一人民医院收治的60例RA活动期患者纳入研究,按照随机数表法分为常规组和联合组各30例。常规组患者给予甲氨蝶呤治疗,联合组患者给予烧山火针刺法联合甲氨蝶呤治疗,均治疗两周。于治疗两周后比较两组患者的治疗效果,以及治疗前后的中医证候评分、28个关节疾病活动(DAS28)评分、疼痛(VAS)评分、炎性指标[血沉(ESR)、C反应蛋白(CRP)、肿瘤坏死因子-α (TNF-α)、类风湿因子(RF)、抗环瓜氨酸肽(CCP)抗体]、免疫指标(Treg细胞、Th17细胞、Treg/Th17细胞),同时比较两组患者治疗期间的不良反应发生情况。结果联合组患者的治疗总有效率为93.33%,明显高于常规组的73.33%,差异有统计学意义(P0.05)。结论烧山火针刺法联合甲氨蝶呤治疗RA活动期能明显减轻患者的临床症状,降低炎症反应,调节免疫功能,临床应用疗效显著,且安全性良好。

关键词：类风湿关节炎活动期烧山火针刺法甲氨蝶呤治疗效果炎症因子免疫功能

Assessment of the three representative empirical models for zenith tropospheric delay(ZTD)using the CMONOC data

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Geodesy and Geodynamics 2024年第5期15卷 488-494页

作者： Debao Yuan jian Li Yifan Yao fei Yang Yingying Wang Ran chen Tairan Xu College of Geoscience and Surveying Engineering China University of Mining and Technology-BeijingBeijing100083China Hubei Luojia Laboratory Wuhan430079China

The precise correction of atmospheric zenith tropospheric delay(ZTD)is significant for the Global Navigation Satellite System(GNSS)performance regarding positioning accuracy and convergence *** the past decades,many empirical ZTD models based on whether the gridded or scattered ZTD products have been proposed and widely used in the GNSS positioning *** there is no comprehensive evaluation of these models for the whole China region,which features complicated topography and *** this study,we completely assess the typical empirical models,the IGGtropSH model(gridded,non-meteorology),the SHAtropE model(scattered,non-meteorology),and the GPT3 model(gridded,meteorology)using the Crustal Movement Observation Network of China(CMONOC)*** general,the results show that the three models share consistent performance with RMSE/bias of 37.45/1.63,37.13/2.20,and 38.27/1.34 mm for the GPT3,SHAtropE and IGGtropSH model,***,the models had a distinct performance regarding geographical distribution,elevation,seasonal variations,and daily *** the southeastern region of China,RMSE values are around 50 mm,which are much higher than that in the western region,approximately 20 *** SHAtropE model exhibits better performance for areas with large variations in *** GPT3 model and the IGGtropSH model are more stable across different months,and the SHAtropE model based on the GNSS data exhibits superior performance across various UTC epochs.

关键词： GNSS Zenith tropospheric delay Empirical ZTD model CMONOC data

Impact of initial fluctuations and nuclear deformations in isobar collisions

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Nuclear Science and Techniques 2024年第6期35卷 155-162页

作者： jian-fei Wang Hao-Jie Xu Fu-Qiang Wang Department of Modern Physics University of Science and Technology of ChinaHefei 230026China School of Science Huzhou UniversityHuzhou 313000China Strong-Coupling Physics International Research Laboratory(SPiRL) Huzhou UniversityHuzhou 313000China Department of Physics and Astronomy Purdue UniversityWest LafayetteIN 47907USA

Relativistic isobar^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zrcollisions have revealed intricate differences in their nuclear size and shape,inspiring unconventional studies of nuclear structure using relativistic heavy ion *** this study,we investigate the relative differences in the mean multiplicityR_()and the secondR_(ε2)and third-order eccentricityR_(ε3)between isobar collisions using initial state Glauber *** is found that initial fluctuations and nuclear deformations have negligible effects on R_()in most central collisions,while both are important for the R_(ε2)and R_(ε3),the degree of which is sensitive to the underlying nucleonic or sub-nucleonic degree of *** features,compared to real data,may probe the particle production mechanism and the physics underlying nuclear structure.

关键词： Relativistic isobar collisions Initial fluctuations Nuclear deformation

Regulating metal-acid double site balance on mesoporous SiO2-Al2O3 composite oxide for supercritical n-decane cracking

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Petroleum Science 2024年第4期21卷 2881-2891页

作者： Liu-Ling chen Jun Zhang Chun-Guang Li Li-Qun fei Bo Wang chen-Qi Zhang Yi Jiao jian-Li Wang Institute of New Energy and Low-Carbon Technology Sichuan University Engineering Research Center of Combustion and Cooling for Aerospace Power Ministry of Education School of Chemical Engineering Sichuan University State Key Laboratory of Industrial Vent Gas Reuse Southwest Institute of Chemical Co. Ltd Science and Technology on Scramjet Laboratory Beijing Power Machinery Research Institute

The balance between metal and acid sites directly affects the preparation of high-performance cracking catalysts with high heat sink and low ***,how to control acid-metal sites balance and its relationship with cracking performance are reported *** this work,a series of Pt/Al2O3-SiO2dual sites catalysts with different metal to acid active sites ratio(CM/CSA) were constructed by ethanolassisted impregnation method and the impact on n-decane cracking under supercritical conditions was systematically and deeply *** results showed that the conversion and carbon deposition increased gradually with varied CM/CSAand reached the balance at CM/CSAof *** proper ratio CM/CSA（0.13） can balance the deep dehydrogenation coking over metal active sites and high heat sink of cracking over acid active sites,the chemical heat sink reaches amazing 1.75 MJ/kg and carbon deposition is only22.03 mg/cm2at 750℃.Meanwhile,the few metal sites at low CM/CSAand the few strong acid sites at high CM/CSAare the main factors limiting the cracking *** CM/CSAlimit the activation of C-H bond and deep dehydrogenation of coking precursor,resulting in relative low cracking activity and carbon deposition,while high CM/CSAlimit the activation of C-C bond and increase the deep *** this contribution,design and construction of metal-acid dual sites can not only provide the technical solution for the preparation of high heat sink and low coking cracking catalyst,but also deepen the understanding of the cracking path of hydrocarbon fuel.

关键词： Metal-acid dual sites balance Catalytic cracking Hydrocarbon fuels Chemical heat sink Carbon deposition

Electrolyte effect on electrochemical behaviors of manganese fluoride material for aqueous asymmetric and symmetric supercapacitors

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Rare Metals 2024年第3期43卷 1048-1061页

作者： Zheng-Hua He jian-fei Gao Ling-Bin Kong State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou University of TechnologyLanzhou730050China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou730050China

Exploring wide voltage window materials is not only an available measure to enhance the energy density of hybrid supercapacitor(HSCs),but also avoids the dynamic mismatch caused by different energy storage mechanisms of two electrodes in assembled symmetrical ***,there are few reports about the wide potential window materials except Bi_(2)O_(3)and VO_(2).Therefore,the MnF_(2)synthesized by solvothermal reaction was served as the electrode for *** MnF_(2)exhibited electrochemical activity in alkaline solution in three-electrode system,especially with a wide potential window from-0.8 to+0.5 V in 2 mol·L^(-1)***,the assembled MnF_(2)//MnF_(2)symmetrical HSC had a potential window of 1.5 V,and it exhibited outstanding long-cycle ***,when MnF_(2)was taken as the negative and positive respectively,the potential windows of asymmetric devices CoMoO_(4)//MnF_(2)and MnF_(2)//Activated Carbon(AC)could reach 1.3 and 1.45 V,respectively,showing excellent cycle *** work shows that MnF_(2)material has great research value in HSC,and provides a new research direction for developing high-performance devices.

关键词： Manganese fluoride Potential window Hybrid supercapacitors Electrochemical performance