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Weak Fault Feature Extraction of the Rotating Machinery Using Flexible Analytic Wavelet Transform and Nonlinear Quantum Permutation Entropy
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作者 Lili Bai Wenhui Li +3 位作者 he ren Feng Li TaoYan Lirong Chen 《Computers, Materials & Continua》 SCIE EI 2024年第6期4513-4531,共19页
Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extrac... Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extraction method that combines the Flexible Analytic Wavelet Transform(FAWT)with Nonlinear Quantum Permutation Entropy.FAWT,leveraging fractional orders and arbitrary scaling and translation factors,exhibits superior translational invariance and adjustable fundamental oscillatory characteristics.This flexibility enables FAWT to provide well-suited wavelet shapes,effectively matching subtle fault components and avoiding performance degradation associated with fixed frequency partitioning and low-oscillation bases in detecting weak faults.In our approach,gearbox vibration signals undergo FAWT to obtain sub-bands.Quantum theory is then introduced into permutation entropy to propose Nonlinear Quantum Permutation Entropy,a feature that more accurately characterizes the operational state of vibration simulation signals.The nonlinear quantum permutation entropy extracted from sub-bands is utilized to characterize the operating state of rotating machinery.A comprehensive analysis of vibration signals from rolling bearings and gearboxes validates the feasibility of the proposed method.Comparative assessments with parameters derived from traditional permutation entropy,sample entropy,wavelet transform(WT),and empirical mode decomposition(EMD)underscore the superior effectiveness of this approach in fault detection and classification for rotating machinery. 展开更多
关键词 Rotating machinery quantum theory nonlinear quantum permutation entropy Flexible Analytic Wavelet Transform(FAWT) feature extraction
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NUMERICAL ANALYSIS AND EXPERI-MENT OF UNSTEADY THERMAL FIELD OF ROTOR PLATE FOR EDDY CURRENT RETARDER 被引量:10
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作者 LIU Chengye he ren 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2008年第4期71-75,共5页
The physical model based on heat transfer theory and virtual boundary method for analyzing unsteady thermal field of rotor plate for eddy current retarder used in automobile is established and boundary conditions are ... The physical model based on heat transfer theory and virtual boundary method for analyzing unsteady thermal field of rotor plate for eddy current retarder used in automobile is established and boundary conditions are also defined. The finite element governing equation is derived by Galerkin method. The time differential item is discrete based on Galerkin format that is stable at any condition. And a new style of varying time step method is used in iteration process. The thermal field on the rotor plate at the radial and axle directions is analyzed and varying temperature at appointed points on two side-surfaces is measured. The testing and analytical data are uniform approximately. Finite element method can be used for estimating thermal field of the rotor plate at initial design stage of eddy current retarder. 展开更多
关键词 Eddy current retarder Thermal field Numerical analysis Varying time step method
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Blockage of glucocorticoid receptors during memory acquisition,retrieval and reconsolidation prevents the expression of morphine-induced conditioned place preferences in mice
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作者 Yao-Dong FAN Hai-Chen NIU +6 位作者 Tanzeel Huma Ling LI Gui-Mei WANG Li-Qi XU he ren Yuan-Ye MA Hua-Lin YU 《Zoological Research》 SCIE CAS CSCD 北大核心 2013年第S01期26-34,共9页
Association between the reward caused by consuming drugs and the context in which they are consumed is essential in the formation of morphine-induced conditioned place preference(CPP).Glucocorticoid receptor(GRs)activ... Association between the reward caused by consuming drugs and the context in which they are consumed is essential in the formation of morphine-induced conditioned place preference(CPP).Glucocorticoid receptor(GRs)activation in different regions of the brain affects reward-based reinforcement and memory processing.A wide array of studies have demonstrated that blockage of GRs in some brain areas can have an effect on reward-related memory;however,to date there have been no systematic studies about the involvement of glucocorticoids(GCs)in morphine-related reward memory.Here,we used the GR antagonist RU38486 to investigate how GRs blockage affects the sensitization and CPP behavior during different phases of reward memory included acquisition,retrieval and reconsolidation.Interestingly,our results showed RU38486 has the ability to impair the acquisition,retrieval and reconsolidation of reward-based memory in CPP and sensitization behavior.But RU38486 by itself cannot induce CPP or conditioned place aversion(CPA)behavior.Our data provide a much more complete picture of the potential effects that glucocorticoids have on the reward memory of different phases and inhibit the sensitization behavior. 展开更多
关键词 ADDICTION Conditioned place preference RU38486 Glucocorticoid receptor RETRIEVAL RECONSOLIDATION Reward memory
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Blockage of glucocorticoid receptors during memory acquisition, retrieval and reconsolidation prevents the expression of morphine-induced conditioned place preferences in mice
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作者 Yao-Dong FAN Hai-Chen NIU +6 位作者 Tanzeel Huma Ling LI Gui-Mei WANG Li-Qi XU he ren Yuan-Ye MA Hua-Lin YU 《Zoological Research》 CAS CSCD 北大核心 2013年第1期I0031-I0039,共9页
Association between the reward caused by consuming drugs and the context in which they are consumed is essential in the formation of morphine-induced conditioned place preference (CPP). Glucocorticoid receptor (GRs) a... Association between the reward caused by consuming drugs and the context in which they are consumed is essential in the formation of morphine-induced conditioned place preference (CPP). Glucocorticoid receptor (GRs) activation in different regions of the brain affects reward-based reinforcement and memory processing. A wide array of studies have demonstrated that blockage of GRs in some brain areas can have an effect on reward-related memory; however, to date there have been no systematic studies about the involvement of glucocorticoids (GCs) in morphine-related reward memory. Here, we used the GR antagonist RU38486 to investigate how GRs blockage affects the sensitization and CPP behavior during different phases of reward memory included acquisition, retrieval and reconsolidation. Interestingly, our results showed RU38486 has the ability to impair the acquisition, retrieval and reconsolidation of reward-based memory in CPP and sensitization behavior. But RU38486 by itself cannot induce CPP or conditioned place aversion (CPA) behavior. Our data provide a much more complete picture of the potential effects that glucocorticoids have on the reward memory of different phases and inhibit the sensitization behavior. 展开更多
关键词 ADDICTION Conditioned place preference RU38486 Glucocorticoid receptor RETRIEVAL RECONSOLIDATION Reward memory
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新型液阻式泵阀冲击特性研究
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作者 莫丽 何任 +1 位作者 冯满 刘傲 《流体机械》 CSCD 北大核心 2024年第8期54-60,共7页
为了降低阀芯与阀座冲击应力减小二者间冲击磨损,提出一种液阻式新型泵阀。采用数值仿真方法对泵阀液阻结构参数进行了优化,并仿真计算了阀芯与阀座的冲击速度和泵阀碰撞冲击的压力接触情况。对比分析了液阻泵阀和传统泵阀的运动特征及... 为了降低阀芯与阀座冲击应力减小二者间冲击磨损,提出一种液阻式新型泵阀。采用数值仿真方法对泵阀液阻结构参数进行了优化,并仿真计算了阀芯与阀座的冲击速度和泵阀碰撞冲击的压力接触情况。对比分析了液阻泵阀和传统泵阀的运动特征及冲击应力结果,并搭建试验台架对仿真模型结果进行验证。结果表明,在阀芯下落阶段,带液阻结构的泵阀的回落速度明显小于传统泵阀,传统泵阀阀芯与阀座相接触的速度达到了0.118 m/s,而带液阻结构泵阀的阀芯与阀座相接触的速度仅为传统泵阀的1/6左右,约为0.02 m/s;带液阻结构的泵阀只发生了1次碰撞,而传统泵阀发生了2次碰撞,在碰撞时,带液阻结构的泵阀阀芯与阀座上的最大接触应力约为260 MPa,而传统泵阀第1次碰撞为190 MPa,第2次为270 MPa;液阻式泵阀能明显降低阀芯与阀座相接触的速度,降低冲击应力,从而减小泵阀的冲击磨损。研究结果可为液阻式泵阀的设计和应用提供参考。 展开更多
关键词 压裂泵泵阀 优化分析 数值仿真 液体阻尼 冲击应力
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水润滑轴承用聚合物复合材料的摩擦学研究进展 被引量:2
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作者 田颖 车清论 +2 位作者 贺仁 张嘎 郑少梅 《材料保护》 CAS CSCD 2024年第1期111-122,162,共13页
聚合物复合材料因其优异的自润滑、高化学稳定性和减振降噪等特性而备受关注。以水作为工作介质的水润滑轴承具有环境友好、维护成本低及结构设计简单等特点,已被广泛应用于船舶、水电和化工等领域。首先总结了水润滑轴承用聚合物复合... 聚合物复合材料因其优异的自润滑、高化学稳定性和减振降噪等特性而备受关注。以水作为工作介质的水润滑轴承具有环境友好、维护成本低及结构设计简单等特点,已被广泛应用于船舶、水电和化工等领域。首先总结了水润滑轴承用聚合物复合材料特性,归纳了聚合物复合材料在水润滑条件下的摩擦学性能及磨损机制,介绍了提高聚合物复合材料摩擦学性能的常规方法,并进一步探讨了材料内部结构、摩擦界面微观结构与材料宏观摩擦学特性的内在关联。指出促进水润滑聚合物-金属配副摩擦界面原位生长固体润滑特性转移膜,可弥补水膜润滑能力不足、显著提高配副的摩擦学性能,深入研究水润滑状态下复合材料的微观摩擦磨损机制,对于理解水润滑配副的摩擦学机理有重要的意义。 展开更多
关键词 水润滑轴承 聚合物复合材料 转移膜 摩擦学机理
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振动能量回收减速带建模与动力学特性研究
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作者 郭炎 何仁 +1 位作者 廖旭晖 徐年尧 《机械设计与制造》 北大核心 2024年第1期100-106,共7页
为了开发应用振动能量回收减速带,分析振动能量回收减速带参数与汽车悬架参数的耦合特性机理。首先分析了液压式振动能量回收减速带的工作原理;其次,研究了减速带的动态模型激励函数,并建立二自由度车辆—换能器模型,并从换能器的作用... 为了开发应用振动能量回收减速带,分析振动能量回收减速带参数与汽车悬架参数的耦合特性机理。首先分析了液压式振动能量回收减速带的工作原理;其次,研究了减速带的动态模型激励函数,并建立二自由度车辆—换能器模型,并从换能器的作用机理入手,通过复模态理论分析车辆—换能器的振动模型动力学特性;最后,依据振动能量回收减速带与汽车悬架系统的耦合动力学模型,对采用不同参数的振动能量回收减速带对汽车运动特性的影响进行了分析;并从回收能量潜能大小的角度分析了汽车悬架参数对振动能量回收减速带运动特性的影响。为振动能量回收减速带的设计提供了理论参考。 展开更多
关键词 减速带 振动能量回收 复模态理论 耦合动力学模型 动力学特性
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基于Informer的电离层电子总量预测
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作者 马艳 刘海军 +3 位作者 贺忍 崔春杰 王高远 杨月巧 《电脑与电信》 2024年第1期17-20,共4页
电离层会影响卫星导航和通信信号的传播和反射,而电离层总电子含量(TEC)则是评估电离层异常扰动的关键指标,因此,精准预测电离层TEC具有重要意义。本研究从国际GNSS服务(IGS)电离层分析中心获取全球1999—2011年的电离层TEC的时间序列数... 电离层会影响卫星导航和通信信号的传播和反射,而电离层总电子含量(TEC)则是评估电离层异常扰动的关键指标,因此,精准预测电离层TEC具有重要意义。本研究从国际GNSS服务(IGS)电离层分析中心获取全球1999—2011年的电离层TEC的时间序列数据,时间分辨率为2小时。选取5个位置,构建了Informer模型预测未来24小时的TEC数据,为研究电离层异常扰动提供科学依据。在多个模型对比中,Informer模型的R-Squared和RMSE表现最佳,验证了Informer方法的可行性。 展开更多
关键词 电离层TEC INFORMER 时间序列 深度学习
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“双创”背景下经济管理类任选课教学改革研究——以“财务管理”课程为例
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作者 何任 方雨婷 《教育教学论坛》 2024年第1期62-65,共4页
在目前高校创新创业课程体系仍不够健全完善的情况下,经管类任选课是非经管类专业学生学习创业所需经济管理知识的重要途径,但现有经管类任选课普遍存在无法满足学生创新创业实践需求的局限性。以“财务管理”课程为例,提出了通过改革... 在目前高校创新创业课程体系仍不够健全完善的情况下,经管类任选课是非经管类专业学生学习创业所需经济管理知识的重要途径,但现有经管类任选课普遍存在无法满足学生创新创业实践需求的局限性。以“财务管理”课程为例,提出了通过改革现有经管类任选课以丰富完善高校创新创业课程体系的思路,分析了“双创”背景下经管类任选课教学需向创新创业类任选课改革的必要性,并分析了当前“财务管理”课程教学中普遍存在的问题,提出了“财务管理”课程教学改革的策略,以期为高校健全完善创新创业课程体系和提高学生创新创业能力的教学改革探索提供参考。 展开更多
关键词 创新创业 任选课 财务管理 教学改革
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医疗机构外购抗菌药物信息化管理实践与探索
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作者 何仁 陈旭 +1 位作者 林利芬 夏哲林 《医院管理论坛》 2024年第8期66-68,71,共4页
目的加强医疗机构外购抗菌药物管理,确保患者用药安全有效。方法基于药房库存系统、住院医生工作站、合理用药软件、浙政钉和微信群,建立无感式抗菌药物合理使用全流程监管系统,简化医疗机构外购抗菌药物审批流程,规范外购抗菌药物合理... 目的加强医疗机构外购抗菌药物管理,确保患者用药安全有效。方法基于药房库存系统、住院医生工作站、合理用药软件、浙政钉和微信群,建立无感式抗菌药物合理使用全流程监管系统,简化医疗机构外购抗菌药物审批流程,规范外购抗菌药物合理使用。结果实施无感式监管系统后,外购抗菌药物的使用更加规范,大大简化了处方流程,节约了人力成本。结论无感式监管系统能有效缩减处方流程,规范医疗机构外购抗菌药物管理,提高患者满意度。 展开更多
关键词 外购抗菌药物 信息化管理 流程改进
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一种水泥激发剂的制备及性能研究
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作者 姜文凯 贺任 +2 位作者 张庆 李兴 王君 《辽宁化工》 CAS 2024年第9期1442-1446,共5页
针对市面上一些普通硅酸盐水泥出现早期强度过低的现象,设计出的一种能激发水泥早期强度且不影响后期强度的水泥激发剂。介绍了水泥激发剂在提高水泥早期强度中的作用机理,并通过对其性能的实验研究,最终确定了最优配方,后续通过生产工... 针对市面上一些普通硅酸盐水泥出现早期强度过低的现象,设计出的一种能激发水泥早期强度且不影响后期强度的水泥激发剂。介绍了水泥激发剂在提高水泥早期强度中的作用机理,并通过对其性能的实验研究,最终确定了最优配方,后续通过生产工艺参数优化,成功实现其在工业化生产中的应用,降低了水泥生产成本以及碳排放量,助力厂家实现高质量、可持续发展战略。 展开更多
关键词 水泥早期强度 碱激发 成型
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A review of UAV monitoring in mining areas: current status and future perspectives 被引量:11
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作者 he ren Yanling Zhao +1 位作者 Wu Xiao Zhenqi Hu 《International Journal of Coal Science & Technology》 EI 2019年第3期320-333,共14页
With the emergence and development of unmanned aerial vehicles (UAVs), different sensors have become more miniaturized and intelligent. UAVs equipped with various sensors are now an important approach for acquiring sp... With the emergence and development of unmanned aerial vehicles (UAVs), different sensors have become more miniaturized and intelligent. UAVs equipped with various sensors are now an important approach for acquiring spatial data. Many advantages, such as low cost, short revisiting cycle, flexibility and high precision, have made UAVs powerful tools in geological, agricultural, ecological and forestry growth monitoring, as well as evaluation. Now, UAVs are a hotspot in scientific research. Their application in mining areas (MA), although still in its infancy, is developing rapidly in terms of speed, scale and service scope. This research examines aspects such as UAV platforms, different sensors and their application fields, as well as reviewing the advances of scientific research in MA at the present time. By combining current research and the functions of multiple sensors, an application framework for UAV monitoring in MA is constructed. Finally, the challenge and prospects for the development of UAVs and sensors are also considered. This research hopes to provide a technical reference, expanding the knowledge and recognition of UAV monitoring in MA, as well as an assessment of applications in mining, reclamation and environment. 展开更多
关键词 UAV SENSOR MINING areas MONITORING
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VHH212 nanobody targeting the hypoxia-inducible factor 1α suppresses angiogenesis and potentiates gemcitabine therapy in pancreatic cancer in vivo 被引量:3
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作者 Guangbo Kang Min Hu +7 位作者 he ren Jiewen Wang Xin Cheng Ruowei Li Bo Yuan Yasmine Balan Zixuan Bai he Huang 《Cancer Biology & Medicine》 SCIE CAS CSCD 2021年第3期772-787,共16页
Objective:We aimed to develop a novel anti-HIF-1αintrabody to decrease gemcitabine resistance in pancreatic cancer patients.Methods:Surface plasmon resonance and glutathione S-transferase pull-down assays were conduc... Objective:We aimed to develop a novel anti-HIF-1αintrabody to decrease gemcitabine resistance in pancreatic cancer patients.Methods:Surface plasmon resonance and glutathione S-transferase pull-down assays were conducted to identify the binding affinity and specificity of anti-HIF-1αVHH212[a single-domain antibody(nanobody)].Molecular dynamics simulation was used to determine the protein-protein interactions between hypoxia-inducible factor-1α(HIF-1α)and VHH212.The real-time polymerase chain reaction(PCR)and Western blot analyses were performed to identify the expressions of HIF-1αand VEGF-A in pancreatic ductal adenocarcinoma cell lines.The efficiency of the VHH212 nanobody in inhibiting the HIF-1 signaling pathway was measured using a dual-luciferase reporter assay.Finally,a PANC-1 xenograft model was developed to evaluate the anti-tumor efficiency of combined treatment.Immunohistochemistry analysis was conducted to detect the expressions of HIF-1αand VEGF-A in tumor tissues.Results:VHH212 was stably expressed in tumor cells with low cytotoxicity,high affinity,specific subcellular localization,and neutralization of HIF-1αin the cytoplasm or nucleus.The binding affinity between VHH212 and the HIF-1αPAS-B domain was 42.7 n M.Intrabody competitive inhibition of the HIF-1αheterodimer with an aryl hydrocarbon receptor nuclear translocator was used to inhibit the HIF-1/VEGF pathway in vitro.Compared with single agent gemcitabine,co-treatment with gemcitabine and a VHH212-encoding adenovirus significantly suppressed tumor growth in the xenograft model with 80.44%tumor inhibition.Conclusions:We developed an anti-HIF-1αnanobody and showed the function of VHH212 in a preclinical murine model of PANC-1 pancreatic cancer.The combination of VHH212 and gemcitabine significantly inhibited tumor development.These results suggested that combined use of anti-HIF-1αnanobodies with first-line treatment may in the future be an effective treatment for pancreatic cancer. 展开更多
关键词 Pancreatic cancer nanobody therapeutic intracellular antibody HIF-1αinhibitor GEMCITABINE CHEMOSENSITIZER
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Direct Z-scheme WO_(3-x) nanowire-bridged TiO_(2) nanorod arrays for highly efficient photoelectrochemical overall water splitting 被引量:2
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作者 Sheng Lin he ren +7 位作者 Zhi Wu Lan Sun Xia-Guang Zhang Yu-Mei Lin Kelvin H.L.Zhang Chang-Jian Lin Zhong-Qun Tian Jian-Feng Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第8期721-729,I0015,共10页
All-solid-state Z-scheme photocatalysts for overall water splitting to evolve H_(2) is a promising strategy for efficient conversion of solar energy.However,most of these strategies require redox mediators.Herein,a di... All-solid-state Z-scheme photocatalysts for overall water splitting to evolve H_(2) is a promising strategy for efficient conversion of solar energy.However,most of these strategies require redox mediators.Herein,a direct Z-scheme photoelectrocatalytic electrode based on a WO_(3-x)nanowire-bridged TiO_(2)nanorod array heterojunction is constructed for overall water splitting,producing H_(2).The as-prepared WO_(3-x)/TiO_(2)nanorod array heterojunction shows photoelectrochemical(PEC)overall water splitting activity evolving both H_(2) and O_(2)under UV-vis light irradiation.An optimum PEC activity was achieved over a 1.67-WO_(3-x)/TiO_(2)photoelectrode yielding maximum H_(2) and O_(2)evolution rates roughly 11 times higher than that of pure TiO_(2)nanorods without any sacrificial agent or redox mediator.The role of oxygen vacancy in WO_(3-x)in affecting the H_(2) production rate was also comprehensively studied.The superior PEC activity of the WO_(3-x)/TiO_(2)electrode for overall water splitting can be ascribed to an efficient Z-scheme charge transfer pathway between the WO_(3-x)nanowires and TiO_(2)nanorods,the presence of oxygen vacancies in WO_(3-x),and a bias potential applied on the photoelectrode,resulting in effective spatial charge separation.This study provides a novel strategy for developing highly efficient PECs for overall water splitting. 展开更多
关键词 TiO_(2) nanorod arrays WO_(3-x) nanowire Heterostructure PHOTOELECTROCHEMICAL Hydrogen production
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分数阶互补滑模控制的永磁同步电机控制 被引量:1
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作者 颜渐德 何仁 谢卫才 《湖南工程学院学报(自然科学版)》 2023年第3期8-15,共8页
针对永磁同步电机(PMSM)伺服系统的参数时变和外部负载扰动,结合干扰观测器(DOB)和滑模控制的优点,引入分数阶互补滑模理论,提出基于干扰观测器的分数阶互补滑模控制(CFOSMC).首先,构造一个非线性干扰观测器,在此基础上设计分数阶滑模,... 针对永磁同步电机(PMSM)伺服系统的参数时变和外部负载扰动,结合干扰观测器(DOB)和滑模控制的优点,引入分数阶互补滑模理论,提出基于干扰观测器的分数阶互补滑模控制(CFOSMC).首先,构造一个非线性干扰观测器,在此基础上设计分数阶滑模,采用带有饱和函数的控制律,以减少现有分数阶滑模控制(FOSMC)中的抖振问题.然后,为了减少边界层厚度,设计了CFOSMC方案,利用李亚普诺夫稳定性定理,分析了存在条件和抖振问题.最后,通过仿真分析,与现有FOSMC方案相比,验证了CFOSMC方法对参数变化及外部干扰具有更强的鲁棒性,并能保证更精确的跟踪性能. 展开更多
关键词 永磁同步电机 滑模控制 干扰观测器 分数阶
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BOPP薄膜热封温度对其包装成型光学性能的影响
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作者 贺韧 闫爱华 +2 位作者 方鑫 汤世祥 黄正涛 《现代化工》 CAS CSCD 北大核心 2023年第S02期225-227,232,共4页
双向拉伸聚丙烯(BOPP)薄膜热封温度对产品的质量、外观带来最直接的影响。目前BOPP薄膜的最佳热封温度范围为135~160℃,通过对BOPP薄膜热封温度的控制,从薄膜的成分、表面形貌、透光率等方面展开了深入研究。结果表明,在热封温度为155... 双向拉伸聚丙烯(BOPP)薄膜热封温度对产品的质量、外观带来最直接的影响。目前BOPP薄膜的最佳热封温度范围为135~160℃,通过对BOPP薄膜热封温度的控制,从薄膜的成分、表面形貌、透光率等方面展开了深入研究。结果表明,在热封温度为155℃下的薄膜性能达到最优,其透光率达到92.5%,薄膜表面形貌排列整齐;经过3个月的存放后,透光率仍能够达到89.5%,仅降低3.2%。 展开更多
关键词 BOPP薄膜 热封温度 透光率
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A drone‑and feld‑based investigation of the land degradation and soil erosion at an opencast coal mine dump after 5 years’evolution of natural processes
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作者 Wu Xiao he ren +3 位作者 Tao Sui heyu Zhang Yanling Zhao Zhenqi Hu 《International Journal of Coal Science & Technology》 EI CAS CSCD 2022年第3期50-66,共17页
Opencast coal mining has a large impact on the land surface,both at the mining pits themselves and at waste sites.After artifcial management is stopped,a reclaimed opencast coal mine dump is afected by wind and water ... Opencast coal mining has a large impact on the land surface,both at the mining pits themselves and at waste sites.After artifcial management is stopped,a reclaimed opencast coal mine dump is afected by wind and water erosion from natural processes,resulting in land degradation and even safety incidents.In this paper,the soil erosion and land degradation after 5 years of such natural processes,at the Xilinhot opencast coal mine dump in Inner Mongolia,were investigated.A multisource data acquisition method was applied:the vegetation fraction coverage(VFC)was extracted from GF-1 satellite imagery,high-precision terrain characteristics and the location and degree of soil erosion were obtained using a drone,and the physical properties of the topsoil were obtained by feld sampling.On this basis,the degree and spatial distribution of erosion cracks were identifed,and the causes of soil erosion and land degradation were analyzed using the geographical detector.The results show that(1)multi-source data acquisition method can provide efective basic data for the quantitative evaluation of the ecological environment at dumps,and(2)slope aspect and VFC are the main factors afecting the degree of degradation and soil erosion.Based on above analysis,several countermeasures are proposed to mitigate land degradation:(1)The windward slope be designed to imitate the natural landform.(2)Reasonable engineering measures should be applied at the slope to restrain soil erosion.(3)The Pioneer plants should be widely planted on the platform at the early stage of reclamation. 展开更多
关键词 Coal mine dump Ecological restoration DRONE Soil erosion Ecosystem stability Geographical detector
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Epithelial cells mimic immune cells: a novel path toward tumor immunotherapy
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作者 Ruining Gong Yan Huang +3 位作者 Xiaoxuan Wang Xiaobing Chen Zibin Tian he ren 《Cancer Biology & Medicine》 SCIE CAS CSCD 2021年第4期937-939,共3页
Recently,we have shown that FOXP3,a critical transcription factor in regulatory T cells(Tregs),is expressed in pancreatic epithelial cells,and restrain the activity of CD8+T cells by upregulating PD-L1,which in turn r... Recently,we have shown that FOXP3,a critical transcription factor in regulatory T cells(Tregs),is expressed in pancreatic epithelial cells,and restrain the activity of CD8+T cells by upregulating PD-L1,which in turn regulates immune escape in pancreatic ductal adenocarcinoma(PDAC)^(1).On the basis of a series of studies of our laboratory,we hypothesize that a subset of pancreatic epithelial cells mimics the phenotype and function of Tregs(named quasi-Tregs or qTregs);this concept has been supported by a peer-reviewed commentary^(2).Moreover,evidence suggests that tumor epithelial cells can mimic other types of immune cells and participate in the formation of a tumor immunosuppressive microenvironment(TIM). 展开更多
关键词 IMMUNE TUMOR ADENOCARCINOMA
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电容式柔性压力传感器的性能优化原理及研究进展 被引量:4
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作者 田玉玉 何韧 +2 位作者 吴菊英 钟卫洲 张凯 《材料导报》 CSCD 北大核心 2023年第16期9-22,共14页
作为可穿戴电子器件的重要分支,柔性压力传感器在人机交互、健康监测等方面具有广阔的应用前景。随着新型材料与新的器件制备策略的不断开发,柔性压力传感器的力学与电学性能不断被优化以适应不同的应用需求。相较于其他传感器,电容式... 作为可穿戴电子器件的重要分支,柔性压力传感器在人机交互、健康监测等方面具有广阔的应用前景。随着新型材料与新的器件制备策略的不断开发,柔性压力传感器的力学与电学性能不断被优化以适应不同的应用需求。相较于其他传感器,电容式柔性压力传感器具有灵敏度高、功耗低、响应快的优势。电容式柔性压力传感器的性能优化主要通过改变器件的结构参数来实现,如电极有效正对面积、电极间距、有效介电常数等。主要方法策略包括新型纳米材料的应用、新型微结构设计和新型复合材料的开发。主要优化原理有四种:(1)通过改变电极表面粗糙度来改变电极有效正对面积;(2)在电极或介电层中引入空气层以降低弹性模量;(3)在介电层中引入空气或高介电常数材料来改变有效介电常数;(4)通过复合材料在介电层中形成微电容以改变总体电容变化。在电容式柔性压力传感器的性能优化研究中存在一个共性问题,即高灵敏度与宽检测范围之间总是存在一种制约关系。在一定压力范围内,尤其是低压范围,灵敏度提升往往会使器件较易达到压缩饱和而使检测范围有限,即线性度较差。近年来,研究者们着眼于高灵敏度与宽检测范围之间的制约问题,对介电层的梯度结构设计及混合响应机制进行探索,取得了丰硕的成果,在保证高灵敏度的前提下大幅提升了器件的检测范围。然而,迟滞、稳定性及阵列优化仍是电容式柔性压力传感器面向实际应用时存在的问题。本文系统归纳了电容式柔性压力传感器的性能优化原理,分别对电极和介电层的结构设计与材料优化方法进行了介绍,分析了电容式柔性压力传感器在性能优化研究中面临的难题,并进行了展望,以期为设计和制备满足应用需求条件的高性能柔性压力传感器提供参考。 展开更多
关键词 柔性压力传感器 电容式 微结构设计 复合材料 多级结构 混合响应
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