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Direct Resolution of the Pitch of DNA on Positively Charged Lipid Bilayers by Frequency-Modulation AFM
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作者 张金金 吕军鸿 +3 位作者 孙洁林 胡钧 CZAJKOWSKY Daniel M 沈轶 《Journal of Shanghai Jiaotong university(Science)》 EI 2014年第5期565-568,共4页
High resolution structural studies of DNA and DNA binding proteins by atomic force microscopy(AFM) require well-bound samples on suitably flat substrates. Adsorbing the DNA onto a positively charged supported lipid bi... High resolution structural studies of DNA and DNA binding proteins by atomic force microscopy(AFM) require well-bound samples on suitably flat substrates. Adsorbing the DNA onto a positively charged supported lipid bilayer has previously been shown to be a potentially effective strategy for structural studies with AFM. Here, using our home-built frequency-modulation AFM(FM-AFM), we show that these bilayer substrates are only maximally effective for high resolution AFM when the samples are short, linear DNA, compared with circular plasmid DNA. We find that, with the former sample, the measured width of the DNA is about 2 nm, the known DNA diameter, and there is a clear height modulation along the length of the DNA with a periodicity of about 3.4 nm, in excellent agreement with the known pitch of the double helix. This sample preparation strategy is expected to enable higher resolution studies of DNA and DNA binding proteins with FM-AFM than that can presently be achieved. 展开更多
关键词 frequency-modulation atomic force microscopy(FM-AFM) DNA double helix high resolution
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Re-evaluation of the Widely Applied Force-Frequency Relation for Frequency-Modulation AFM Under Solution
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作者 何健锋 胡钧 +1 位作者 孙洁林 CZAJKOWSKY Daniel M 《Journal of Shanghai Jiaotong university(Science)》 EI 2014年第5期612-616,共5页
Frequency-modulation atomic force microscopy(FM-AFM) is a highly versatile tool for surface science.Besides imaging surfaces, FM-AFM is capable of measuring interactions between the AFM probe and the surface with high... Frequency-modulation atomic force microscopy(FM-AFM) is a highly versatile tool for surface science.Besides imaging surfaces, FM-AFM is capable of measuring interactions between the AFM probe and the surface with high sensitivity, which can provide chemical information at sub-nanometer resolution. This is achieved by deconvoluting the frequency shift, which is directly measured in experiments, into the force between the probe and sample. At present, the widely used method to perform this deconvolution has been shown to be accurate under high quality(high-Q) factor vacuum conditions. However, under low quality(low-Q) factor conditions, such as in solution, it is not clear if this method is valid. A previous study apparently verified this relation for experiments in solution by comparing the force calculated by this equation with that obtained in separate experiments using the surface force apparatus(SFA). Here we show that, in solution, a more direct comparison of the force calculated by this relation with that directly measured by the cantilever deflection in AFM reveals significant differences,both qualitative and quantitative. However, we also find that there are complications that hinder this comparison.Namely, while contact with the surface is clear in the direct measurements(including the SFA data), it is less certain in the FM-AFM case. Hence, it is not clear if the two methods are measuring the same tip-sample distance regimes. Thus, our results suggest that a more thorough verification of this relation is required, as application of this formulation for experiments in solution may not be valid. 展开更多
关键词 frequency-modulation atomic force microscopy(FM-AFM) chemical mapping frequency-force relationship force spectroscopy
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Structure variation of cadmium naphthalene⁃diphosphonates with the changing rigidity of N⁃donor auxiliary ligands
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作者 XU Yan LI Suzhi +3 位作者 LI Yan FENG Lushun SUN Wentao LI Xinxing 《无机化学学报》 北大核心 2025年第2期395-406,共12页
Five cadmium naphthalene-diphosphonates,formulated as[Cd_(1.5)(1,4-ndpaH_(2))2(4,4'-bpyH)(4,4'-bpy)0.5(H_(2)O)_(2)]2(1),[Cd(1,4-ndpaH_(2))(1,4-bib)0.5(H_(2)O)](2),[Cd(1,4-ndpaH3)2(1,2-dpe)(H_(2)O)]·(1,2-d... Five cadmium naphthalene-diphosphonates,formulated as[Cd_(1.5)(1,4-ndpaH_(2))2(4,4'-bpyH)(4,4'-bpy)0.5(H_(2)O)_(2)]2(1),[Cd(1,4-ndpaH_(2))(1,4-bib)0.5(H_(2)O)](2),[Cd(1,4-ndpaH3)2(1,2-dpe)(H_(2)O)]·(1,2-dpe)·7H_(2)O(3),(1,2-bixH)[Cd3(1,4-ndpaH)(1,4-ndpaH_(2))2(H_(2)O)_(2)](4),and[Cd(1,4-ndpaH_(2))(H_(2)O)]·H_(2)O(5),have been synthesized from the selfassembly reactions of 1,4-naphthalenediphosphonic acid(1,4-ndpaH4)with Cd(NO3)2·4H_(2)O by introducing auxiliary ligands with variation of rigidity,such as 4,4'-bipyridine(4,4'-bpy),1,4-bis(1-imidazolyl)benzene(1,4-bib),1,2-di(4-pyridyl)ethylene(1,2-dpe),1,3-di(4-pyridyl)propane(1,3-dpp),and bis(imidazol-1-ylmethyl)benzene(1,2-bix),respectively.Structure resolution by single-crystal X-ray diffraction reveals that compound 1 possesses a layered framework,in which the{Cd3(PO2)2}trimers made up of corner-sharing two{CdO4N2}and one{CdO6}octahedra are connected by phosphonate groups,forming a ribbon,which are cross-linked by 4,4'-bipy ligands,forming a 2D layer.Compound 2 shows a 3D open-framework structure,where chains of corner-sharing{CdO4N}trigonal bipyramids and{PO3C}tetrahedra are cross-linked by 1,4-bib and/or phosphonate groups.A 1D ladder-like chain structure is found in compound 3,where the ladder-like chains made up of corner-sharing{CdO5N}octahedra and{PO3C}tetra hedra are connected by 1,4-ndpaH_(2)^(2-).Both compounds 4 and 5 obtained by the introduction of flexible ligands during the synthesis show a 2D layered structure,which is formed by ligand crosslinking double metal chains.Interestingly,In 4,flexible 1,2-bix was singly protonated,as vip molecules,filled between layer and layer,while flexible ligand 1,3-dpp is absent in 5.Photophysical measurements indicate that compounds 1-5 show ligand-centered emissions. 展开更多
关键词 naphthalene diphosphate N-donor auxiliary ligands crystal structure RIGIDITY flexibility
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Recent Progress in the Auxiliary Phase Enhanced Flexible Piezocomposites
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作者 Xin Gao Mupeng Zheng +5 位作者 Boyue Hou Junshu Wu Mankang Zhu Yunfan Zhang Ke Wang Bing Han 《Energy & Environmental Materials》 2025年第1期292-312,共21页
Piezocomposites with both flexibility and electromechanical conversion characteristics have been widely applied in various fields,including sensors,energy harvesting,catalysis,and biomedical treatment.In the compositi... Piezocomposites with both flexibility and electromechanical conversion characteristics have been widely applied in various fields,including sensors,energy harvesting,catalysis,and biomedical treatment.In the composition of piezocomposites or their preparation process,a category of materials is commonly employed that do not possess piezoelectric properties themselves but play a crucial role in performance enhancement.In this review,the concept of auxiliary phase is first proposed to define these materials,aiming to provide a new perspective for designing high-performance piezocomposites.Three different categories of modulation forms of auxiliary phase in piezocomposites are systematically summarized,including the modification of piezo-matrix,the modification of piezo-fillers,and the construction of special structures.Each category emphasizes the role of the auxiliary phase and systematically discusses the latest advancements and the physical mechanisms of the auxiliary phase enhanced flexible piezocomposites.Finally,a summary and future outlook of piezocomposites based on the auxiliary phase are provided. 展开更多
关键词 auxiliary phase FLEXIBILITY microstructure PIEZOCOMPOSITES PIEZOELECTRICITY
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Unsupervised Meteorological Downscaling Based on Dual Learning and Subgrid-scale Auxiliary Information
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作者 Jing HU Jialing MU +1 位作者 Xiaomeng HUANG Xi WU 《Advances in Atmospheric Sciences》 2025年第1期53-66,共14页
Climate downscaling is used to transform large-scale meteorological data into small-scale data with enhanced detail,which finds wide applications in climate modeling,numerical weather forecasting,and renewable energy.... Climate downscaling is used to transform large-scale meteorological data into small-scale data with enhanced detail,which finds wide applications in climate modeling,numerical weather forecasting,and renewable energy.Although deeplearning-based downscaling methods effectively capture the complex nonlinear mapping between meteorological data of varying scales,the supervised deep-learning-based downscaling methods suffer from insufficient high-resolution data in practice,and unsupervised methods struggle with accurately inferring small-scale specifics from limited large-scale inputs due to small-scale uncertainty.This article presents DualDS,a dual-learning framework utilizing a Generative Adversarial Network–based neural network and subgrid-scale auxiliary information for climate downscaling.Such a learning method is unified in a two-stream framework through up-and downsamplers,where the downsampler is used to simulate the information loss process during the upscaling,and the upsampler is used to reconstruct lost details and correct errors incurred during the upscaling.This dual learning strategy can eliminate the dependence on high-resolution ground truth data in the training process and refine the downscaling results by constraining the mapping process.Experimental findings demonstrate that DualDS is comparable to several state-of-the-art deep learning downscaling approaches,both qualitatively and quantitatively.Specifically,for a single surface-temperature data downscaling task,our method is comparable with other unsupervised algorithms with the same dataset,and we can achieve a 0.469 dB higher peak signal-to-noise ratio,0.017 higher structural similarity,0.08 lower RMSE,and the best correlation coefficient.In summary,this paper presents a novel approach to addressing small-scale uncertainty issues in unsupervised downscaling processes. 展开更多
关键词 DOWNSCALING UNSUPERVISED deep learning dual learning auxiliary information
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Analysis of auxiliary antenna array effect on performance of wideband noncooperative interference cancellation
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作者 LI Zheyu LI Yaxing +3 位作者 WANG Ze LIANG Jiaqi HE Fangmin MENG Jin 《Journal of Systems Engineering and Electronics》 2025年第5期1188-1201,共14页
In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the i... In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the interference signal determines interference cancellation performance,while the auxiliary antenna array affects the correlation by influencing the amplitude and phase of the reference signals.This paper analyzes the effect of auxiliary antenna array on multiple performances of wideband noncooperative interference cancellation.Firstly,the array received signal model of wideband interference is established,and the weight vector coupled with the auxiliary antennas array manifold is solved by spectral analysis and eigen-subspace decomposition.Then,multiple performances which include cancellation resolution,grating null,wideband interference cancellation ratio(ICR),and convergence rate are quantitatively characterized with the auxiliary antenna array.It is obtained through analysis that the performances mutually restrict the auxiliary antenna array.Higher cancellation resolution requires larger array aperture,but when the number of auxiliary antennas is fixed,larger array aperture results in more grating nulls.When the auxiliary antennas are closer to the main antenna,the wideband ICR is improved,but the convergence rate is reduced.The conclusions are verified through simulation of one-dimensional uniform array and two-dimensional nonuniform array.The experiments of three arrays are compared,and the results conform well with simulation and support the theoretical analysis. 展开更多
关键词 auxiliary antenna array noncooperative interference cancellation wideband interference performance analysis
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A High-Order Scalar Auxiliary Variable Approach for Nonlinear Parabolic Integro-Differential Equations
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作者 YAN Li-na ZHANG Gen-gen HUANG Qiong-ao 《Chinese Quarterly Journal of Mathematics》 2025年第3期262-270,共9页
An efficient and accurate scalar auxiliary variable(SAV)scheme for numerically solving nonlinear parabolic integro-differential equation(PIDE)is developed in this paper.The original equation is first transformed into ... An efficient and accurate scalar auxiliary variable(SAV)scheme for numerically solving nonlinear parabolic integro-differential equation(PIDE)is developed in this paper.The original equation is first transformed into an equivalent system,and the k-order backward differentiation formula(BDF k)and central difference formula are used to discretize the temporal and spatial derivatives,respectively.Different from the traditional discrete method that adopts full implicit or full explicit for the nonlinear integral terms,the proposed scheme is based on the SAV idea and can be treated semi-implicitly,taking into account both accuracy and effectiveness.Numerical results are presented to demonstrate the high-order convergence(up to fourth-order)of the developed schemes and it is computationally efficient in long-time computations. 展开更多
关键词 Parabolic integro-differential equation Scalar auxiliary variable Fredholm equation High-order BDF scheme
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Omnidirectional Human Behavior Recognition Method Based on Frequency-Modulated Continuous-Wave Radar
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作者 SUN Chang WANG Shaohong LIN Yanping 《Journal of Shanghai Jiaotong university(Science)》 2025年第4期637-645,共9页
Frequency-modulated continuous-wave radar enables the non-contact and privacy-preserving recognition of human behavior.However,the accuracy of behavior recognition is directly influenced by the spatial relationship be... Frequency-modulated continuous-wave radar enables the non-contact and privacy-preserving recognition of human behavior.However,the accuracy of behavior recognition is directly influenced by the spatial relationship between human posture and the radar.To address the issue of low accuracy in behavior recognition when the human body is not directly facing the radar,a method combining local outlier factor with Doppler information is proposed for the correction of multi-classifier recognition results.Initially,the information such as distance,velocity,and micro-Doppler spectrogram of the target is obtained using the fast Fourier transform and histogram of oriented gradients-support vector machine methods,followed by preliminary recognition.Subsequently,Platt scaling is employed to transform recognition results into confidence scores,and finally,the Doppler-local outlier factor method is utilized to calibrate the confidence scores,with the highest confidence classifier result considered as the recognition outcome.Experimental results demonstrate that this approach achieves an average recognition accuracy of 96.23%for comprehensive human behavior recognition in various orientations. 展开更多
关键词 frequency-modulated continuous-wave radar omnidirectional human behavior recognition histogram of oriented gradients support vector machine micro-Doppler spectrogram Doppler-local outlier factor
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The 2025 National Practical Technology Training on Textile Dyeing and Printing Auxiliaries Preparation Successfully Held
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《China Detergent & Cosmetics》 2025年第3期106-107,共2页
From July 14 to 18,the"2025 National Practical Technology Training on Textile Dyeing and Printing Auxiliaries Preparation"hosted by the National Engineering Research Center for Surfactants and China Research... From July 14 to 18,the"2025 National Practical Technology Training on Textile Dyeing and Printing Auxiliaries Preparation"hosted by the National Engineering Research Center for Surfactants and China Research Institute of Daily Chemical,and co-organized by the Dyeing and Finishing Technology Research Institute of Zhejiang Fashion Institute of Technology was successfully held as scheduled in Guangzhou. 展开更多
关键词 practical technology SURFACTANTS practical technology training printing auxiliaries textile dyeing national engineering research center China Research Institute Daily Chemical
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从GB/T 1182—2018辅助要素框格探究几何公差带的方向特征
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作者 李瑜 卞平艳 +2 位作者 赵明利 张昌娟 魏绍亮 《中国标准化》 2026年第1期155-159,共5页
几何公差带的方向特征与方向公差带,由于术语字面相同,始终是行业人员容易混淆的问题。本文深入剖析两者的概念区别,分析两者在几何公差管控中的实际作用;结合GB/T 1182—2018标准中定向平面和方向要素辅助框格的作用,进一步厘清二者术... 几何公差带的方向特征与方向公差带,由于术语字面相同,始终是行业人员容易混淆的问题。本文深入剖析两者的概念区别,分析两者在几何公差管控中的实际作用;结合GB/T 1182—2018标准中定向平面和方向要素辅助框格的作用,进一步厘清二者术语的差别;最后通过圆锥密封的两个实例,说明方向特征的内涵和方向要素辅助框格的应用。文章有助于工程技术人员准确理解几何公差的方向特征,并规范应用相关标准。 展开更多
关键词 几何公差带 方向特征 方向公差带 辅助公差框格 GB/T 1182—2018
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侧墙小窗辅助进风对网上平养肉鸡舍降温效果的影响
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作者 陈可添 戴志琦 +2 位作者 刘乐 李延森 李春梅 《畜牧与兽医》 北大核心 2026年第1期43-48,共6页
旨在研究侧墙小窗辅助进风技术对网上平养肉鸡舍降温效果的影响。试验选取两栋标准网上平养商品肉鸡舍作为研究对象,一栋作为对照舍(Con舍),不作任何改装,另一栋作为处理舍(Tre舍),在距风机侧约30 m处小窗外安装冷风机,并通过送风带往... 旨在研究侧墙小窗辅助进风技术对网上平养肉鸡舍降温效果的影响。试验选取两栋标准网上平养商品肉鸡舍作为研究对象,一栋作为对照舍(Con舍),不作任何改装,另一栋作为处理舍(Tre舍),在距风机侧约30 m处小窗外安装冷风机,并通过送风带往舍内辅助进风,研究辅助进风对舍内温度和温差的影响,同时对舍内相对湿度、风速、CO_(2)浓度和颗粒物浓度等环境参数进行检测。结果:与Con舍相比,Tre舍内平均温度显著降低(P<0.001),有效缩小舍内的温差,但对鸡舍内的相对湿度无显著影响(P>0.05);Tre舍内风速提高7.27%,CO_(2)浓度下降了7.63%,颗粒物浓度明显降低(P<0.05)。研究表明,侧墙小窗辅助进风技术可有效降低舍内温度、缩小舍内温差、提高局部通风效果和改善空气环境质量。 展开更多
关键词 侧墙小窗 辅助进风 风速 温差
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基于改进PSO的煤矿井下机车运输路径优化调度
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作者 刘登科 张宏伟 《现代电子技术》 北大核心 2026年第2期142-148,共7页
煤矿井下机车作为煤矿井下运输物料矸石工作的主要工具,其运输调度工作影响着煤矿企业生产效率,而传统调度方式主要以人工操作为主,运输效率较低。为提升井下机车运输效率,针对现有的煤矿井下辅助运输调度工作特点与实际调度需求,提出... 煤矿井下机车作为煤矿井下运输物料矸石工作的主要工具,其运输调度工作影响着煤矿企业生产效率,而传统调度方式主要以人工操作为主,运输效率较低。为提升井下机车运输效率,针对现有的煤矿井下辅助运输调度工作特点与实际调度需求,提出一种基于改进粒子群优化(PSO)算法的机车最优调度路径求解方案。该方案以运输原则为约束,构建以最小总运输距离为优化目标的调度模型,为井下机车调度工作提供理论支撑。再对基于改进粒子群优化算法的调度算法进一步优化,通过引入遗传算法(GA)中的交叉变异操作来增强空间粒子的多样性与寻优能力,最终得到最优调度路径。通过Matlab 2022b软件搭建了仿真平台,以首山一矿井下运输矸石实际生产数据为背景,对该算法进行了仿真实验。实验结果表明,所提出的智能井下机车调度算法规划的运输路径更具合理性,不仅提高了机车资源利用率,还显著提升了井下辅助运输作业的整体效率。 展开更多
关键词 井下辅助运输 机车调度 数学模型 改进PSO算法 GA 最短路径
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透明帽辅助内镜下泡沫硬化术治疗内痔的临床效果分析
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作者 许开武 陈鸿西 +1 位作者 侯福涛 喻志革 《首都食品与医药》 2026年第3期49-52,共4页
目的探究透明帽辅助内镜下泡沫硬化术对内痔的治疗效果。方法提取本院收治的Ⅱ-Ⅲ度内痔患者临床资料进行研究(2024年1月-2025年6月)。共纳入患者80例,将住院号录入计算机,随机分为对照组(采用内镜下套扎术治疗)和观察组(采用透明帽辅... 目的探究透明帽辅助内镜下泡沫硬化术对内痔的治疗效果。方法提取本院收治的Ⅱ-Ⅲ度内痔患者临床资料进行研究(2024年1月-2025年6月)。共纳入患者80例,将住院号录入计算机,随机分为对照组(采用内镜下套扎术治疗)和观察组(采用透明帽辅助内镜下泡沫硬化术治疗),对比组间临床效果。结果干预3d、7d时,观察组疼痛评分较低(P<0.05);观察组创面水肿消失时间、创面愈合时间、住院时间较短(P<0.05);观察组干预7d时,排便情况各维度评分较低(P<0.05);组间并发症发生率无显著差异(P>0.05)。结论对内痔手术患者实施透明帽辅助内镜下泡沫硬化术治疗成效显著,有助于促进创面愈合,减轻疼痛。 展开更多
关键词 内痔 透明帽辅助 内镜 泡沫硬化 创面愈合 疼痛
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基于OTPA的辅汽轮发电机组振动传递路径分析
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作者 刘兵 张万福 +2 位作者 赵乾乾 吕学宾 任杰 《动力工程学报》 北大核心 2026年第1期42-50,共9页
针对辅汽轮发电机组振动传递路径不清晰问题,以某高速辅汽轮发电机组为研究对象,建立转子-轴承-定子整机模型,基于工况传递路径分析(operational transfer path analysis,OTPA)方法构建机组振动传递模型,分析机组振动传递规律。首先应... 针对辅汽轮发电机组振动传递路径不清晰问题,以某高速辅汽轮发电机组为研究对象,建立转子-轴承-定子整机模型,基于工况传递路径分析(operational transfer path analysis,OTPA)方法构建机组振动传递模型,分析机组振动传递规律。首先应用有限元方法获取机组各传递路径频率响应函数,综合考虑转子不平衡、脉动汽流力及不平衡磁拉力等激励源,采用奇异值分解技术对各轴承座处输入信号进行降噪合成,构建各路径输入与输出关系的传递函数矩阵,分析不同路径对定子外壳的振动贡献,明确其主要振动传递路径。结果表明:定子外壳各测点振动主要振动路径来源于辅汽轮机的2个轴承座,特别是发电机侧轴承座的振动贡献量最大。通过优化调整该轴承座结构固有特性与转子不平衡力相位差可以有效降低定子外壳振动,最大振幅由364μm降至51μm。研究结果可以为辅汽轮发电机组振动溯源及故障诊断的优化提供参考。 展开更多
关键词 辅汽轮发电机组 OTPA 奇异值分解 有限元分析 不平衡响应
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基于改进辅助分类生成对抗网络的小样本轴承故障诊断
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作者 谢莹 刘雪伟 鲁振杰 《轴承》 北大核心 2026年第1期100-110,共11页
针对实际工业生产中故障数据较难采集,而训练具有良好性能的深度学习模型又依赖于大量数据样本的问题,提出一种改进辅助分类生成对抗网络与注意力机制相结合(M-ACGAN-A)的故障诊断模型。首先,对振动信号进行短时傅里叶变换,将其转化为... 针对实际工业生产中故障数据较难采集,而训练具有良好性能的深度学习模型又依赖于大量数据样本的问题,提出一种改进辅助分类生成对抗网络与注意力机制相结合(M-ACGAN-A)的故障诊断模型。首先,对振动信号进行短时傅里叶变换,将其转化为二维时频图,从而增强数据特征;其次,采用辅助分类生成对抗网络(ACGAN)的生成器学习实际数据样本的分布,生成大量模拟数据样本;然后,利用嵌入注意力机制的分类器进行模型训练,引入Wasserstein距离指导模型缩短源分布与目标分布的差距,并通过谱归一化来防止模型梯度爆炸;最后,利用训练完成的判别器进行故障诊断。采用凯斯西储大学轴承数据集和帕德博恩大学轴承数据集进行试验,结果表明所提模型能够利用有限的数据信息实现故障诊断,相比于其他深度学习模型具有更高的诊断精度和泛化性。 展开更多
关键词 滚动轴承 故障诊断 特征提取 傅里叶变换 小样本 辅助分类生成对抗网络
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数字化转型背景下船舶类新形态教材建设研究——以船舶辅机课程为例
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作者 龚成林 刘世伟 《船舶职业教育》 2026年第1期36-38,共3页
在职业教育数字化转型背景下,开发新形态数字教材与教学资源已成为高职院校推进课程改革、提升人才培养质量的关键任务。针对当前船舶类专业教材存在的形式单一、内容陈旧、职业导向不鲜明等突出问题,以船舶辅机课程为例,系统阐述新形... 在职业教育数字化转型背景下,开发新形态数字教材与教学资源已成为高职院校推进课程改革、提升人才培养质量的关键任务。针对当前船舶类专业教材存在的形式单一、内容陈旧、职业导向不鲜明等突出问题,以船舶辅机课程为例,系统阐述新形态数字教材的开发理念与实践路径。实践表明,新形态教材显著提升教学适配性与学生学习效果,为同类专业教材的数字化改革提供了借鉴。 展开更多
关键词 数字化 新形态教材 船舶辅机 教学质量
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一种基于CNN-Transformer的青光眼辅助诊断双编码分割网络模型
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作者 马宇张 张伟 邵浩辰 《中国医学物理学杂志》 2026年第2期268-275,共8页
视杯与视盘的精准分割是青光眼早期筛查中形态学参数计算的关键环节,针对现有方法因局部-全局特征融合效率低、长距离依赖建模不足导致的边界模糊和分割精度受限问题,提出一种基于CNN-Transformer的青光眼辅助诊断双编码分割网络模型。... 视杯与视盘的精准分割是青光眼早期筛查中形态学参数计算的关键环节,针对现有方法因局部-全局特征融合效率低、长距离依赖建模不足导致的边界模糊和分割精度受限问题,提出一种基于CNN-Transformer的青光眼辅助诊断双编码分割网络模型。首先,设计双分支互补特征融合模块替代传统跳跃连接,通过动态权重分配策略实现CNN局部细节与Transformer全局上下文的协同优化以提升特征融合效率。其次,在Transformer编码器中引入全局注意力增强模块,利用多头自注意力机制建模像素级长距离依赖关系,结合深度可分离卷积增强边界区域的上下文感知能力,有效缓解视杯/视盘边缘不连续问题。在REFUGE数据集上的实验表明,该方法在视盘分割任务中Dice系数和IoU较U-Net分别提升4.11%和5.62%;该方法在视杯分割任务中Dice系数和IoU较U-Net分别提升11.75%和19.30%。 展开更多
关键词 视杯视盘分割 青光眼辅助诊断 TRANSFORMER 特征融合 注意力机制
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种植支抗联合转矩辅弓压低前牙的三维有限元分析
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作者 许畅 姜明珠 +1 位作者 刘鑫 闫伟军 《中国组织工程研究》 北大核心 2026年第8期1971-1978,共8页
背景:对于深覆牙合与露龈笑患者,正畸治疗中常通过微螺钉种植体压低上前牙来打开咬合,但这一方法易引发前牙唇倾。转矩辅弓在正畸中具有独特的力学作用,其是否能够改善前牙唇倾并提升治疗效率值得深入研究。目的:借助有限元法模拟压低... 背景:对于深覆牙合与露龈笑患者,正畸治疗中常通过微螺钉种植体压低上前牙来打开咬合,但这一方法易引发前牙唇倾。转矩辅弓在正畸中具有独特的力学作用,其是否能够改善前牙唇倾并提升治疗效率值得深入研究。目的:借助有限元法模拟压低前牙场景,探究不同前牙唇倾度及转矩辅弓对牙齿移动的影响。方法:基于健康成人的口腔锥形束CT图像,构建不同中切牙及侧切牙唇倾度(105°,112°,120°)的上颌模型,在每组模型双侧上颌中切牙与侧切牙间植入微种植体,并加载60 g拉力;针对每组模型,分别设置转矩辅弓施加0.5,1.0,1.5 N的力及无辅弓,分析上前牙的初始位移、最大主应力分布和Von Mises等效应力分布。结果与结论:①应用转矩辅弓后,随着转矩值的增加,牙冠与牙根的移动方向改变,牙冠由唇向转变为舌向移动,牙根则从舌向转变为唇向移动,并且两者之间的位移差逐渐增大,同时牙根的压低量及牙冠的伸长量均呈现出增大态势;在相同转矩值时,随着牙齿唇倾度的增加,牙根及牙冠在各个方向上的位移量均逐渐变小;②各组模型的最大等效应力分布主要集中在牙颈部边缘和根尖部2个区域,应力值均在正常值范围以内,随着转矩值的增加,Von Mises等效应力逐渐增大;随着唇倾度的增加,Von Mises等效应力变化不显著;③最大主应力-拉应力主要集中在牙周膜的唇侧龈缘部位,压应力主要集中在根尖部,随着转矩值的增大,牙周膜的压应力及拉应力均随之增大;随着唇倾度的增加,牙周膜的应力变化不显著,其中超过1 N的转矩值可能会损伤根尖牙周组织健康;④结果表明,转矩辅弓既能提高前牙压低效率又能改善过度唇倾的前牙,有效控制牙齿转矩,但是为了防止牙根吸收,辅弓施加的力最好选择1 N以内。 展开更多
关键词 转矩辅弓 前牙压低 深覆牙合 微螺钉种植体 转矩 唇倾度 露龈笑 工程化口腔材料
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铁路桥梁健康监测系统综合管理平台设计
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作者 刘兴旺 刘俊锋 +2 位作者 赵大成 王磊磊 何任远 《世界桥梁》 北大核心 2026年第1期1-8,共8页
为解决铁路桥梁健康监测系统存在的数据孤岛严重、系统应用不足、辅助管养不及时等难题,构建铁路桥梁健康监测系统综合管理平台。在满足标准规范体系及安全保障体系的基础上,以系统监管、辅助运维为目标,采用多系统一平台模式设计铁路... 为解决铁路桥梁健康监测系统存在的数据孤岛严重、系统应用不足、辅助管养不及时等难题,构建铁路桥梁健康监测系统综合管理平台。在满足标准规范体系及安全保障体系的基础上,以系统监管、辅助运维为目标,采用多系统一平台模式设计铁路桥梁健康监测系统综合管理平台。该平台采用数据层及应用层为主的平台架构模式,基于铁路综合服务网汇聚各桥健康监测系统数据信息,在平台应用层开发部署系统故障率、数据完整率、报警管理等模块实现对桥梁健康监测系统的有效监管,通过极值工况分析、特殊事件管理、应急管理等模块及多指标综合校验机制辅助桥梁结构安全运维。以某运营大跨度铁路桥梁健康监测系统支座位移监测为例,分析时段系统故障率小于10%,数据完整率大于90%,系统运行良好;并考虑环境温度极值计算支座位移预警阈值,提升了系统对结构异常事件的判别能力,表明该平台可进一步提升铁路桥梁健康监测系统的监管和运维质量,增强系统实用性。 展开更多
关键词 铁路桥 健康监测 平台设计 报警机制 系统监管 辅助运维
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