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Finite-time stability with respect to a closed invariant set for a class of discontinuous systems 被引量:3
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作者 程桂芳 慕小武 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2009年第8期1069-1075,共7页
This paper discusses the problem of finite-time stability with respect to a closed, but not necessarily compact, invariant set for a class of nonlinear systems with discontinuous right-hand sides in the sense of the F... This paper discusses the problem of finite-time stability with respect to a closed, but not necessarily compact, invariant set for a class of nonlinear systems with discontinuous right-hand sides in the sense of the Filippov solutions. When the Lyapunov function is Lipschitz continuous and regular, the Lyapunov theorem on finite-time stability with respect to a closed invariant set is presented. 展开更多
关键词 Filippov solution closed invariant set finite-time stability discontinuous system
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On the Decomposition of a Bounded Closed Interval of the Real Line into Closed Sets
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作者 Edgar A. Cohen 《Advances in Pure Mathematics》 2013年第4期405-408,共4页
It has been shown by Sierpinski that a compact, Hausdorff, connected topological space (otherwise known as a continuum) cannot be decomposed into either a finite number of two or more disjoint, nonempty, closed sets o... It has been shown by Sierpinski that a compact, Hausdorff, connected topological space (otherwise known as a continuum) cannot be decomposed into either a finite number of two or more disjoint, nonempty, closed sets or a countably infinite family of such sets. In particular, for a closed interval of the real line endowed with the usual topology, we see that we cannot partition it into a countably infinite number of disjoint, nonempty closed sets. On the positive side, however, one can certainly express such an interval as a union of c disjoint closed sets, where c is the cardinality of the real line. For example, a closed interval is surely the union of its points, each set consisting of a single point being closed. Surprisingly enough, except for a set of Lebesgue measure 0, these closed sets can be chosen to be perfect sets, i.e., closed sets every point of which is an accumulation point. They even turn out to be nowhere dense (containing no intervals). Such nowhere dense, perfect sets are sometimes called Cantor sets. 展开更多
关键词 CANTOR setS CARDINALITY DISJOINT closed setS DYADIC Representation INTERLACING DYADIC Expansions Generators of setS Nowhere Dense
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Remarks on (1, 2)^*-Generalized Closed Sets with Respect to an Ideal Bitopological Space
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作者 H. S. Al-Saadi Takashi Noiri 《Journal of Mathematics and System Science》 2012年第6期348-351,共4页
In this paper, the authors introduce and study the concept of (1, 2)^*-generalized closed sets with respect to an ideal in a bitopological space. Also, some characterizations and applications of(1, 2)^*-generali... In this paper, the authors introduce and study the concept of (1, 2)^*-generalized closed sets with respect to an ideal in a bitopological space. Also, some characterizations and applications of(1, 2)^*-generalized closed sets are given. 展开更多
关键词 Bitopological space (1 2)^*-generalized closed set topological ideal.
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Intuitionistic Fuzzy α-Generalized Closed Sets in Terms of Minimal Structure Spaces
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作者 Mani Parimala Sivaraman Murali 《Circuits and Systems》 2016年第8期1486-1491,共6页
In this paper, we introduce the notion of intuitionistic fuzzy α-generalized closed sets in intuitionistic fuzzy minimal structure spaces and investigate some of their properties. Further, we introduce and study the ... In this paper, we introduce the notion of intuitionistic fuzzy α-generalized closed sets in intuitionistic fuzzy minimal structure spaces and investigate some of their properties. Further, we introduce and study the concept of intuitionistic fuzzy α-generalized minimal continuous functions. 展开更多
关键词 Intuitionistic Fuzzy Topology Intuitionistic Fuzzy α-Generalized closed set Intuitionistic Fuzzy α-Generalized Continuous Function Intuitionistic Fuzzy α-Generalized Continuous Mappings
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近接运营地铁的城市地下工程施工安全韧性评估方法研究
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作者 韩凯航 李岩松 +6 位作者 陈湘生 包小华 王树英 张成平 魏纲 张治国 赵千 《隧道建设(中英文)》 CSCD 北大核心 2024年第10期2005-2015,共11页
为提出一种用于评估近接运营地铁的城市地下工程施工安全韧性的方法,首先,通过对近接施工的3个方面(新建地下工程、地层、既有地下结构)以及2个维度(技术和管理)的分析,建立一个较为完整的韧性指标体系;其次,结合层次分析法、熵权法和... 为提出一种用于评估近接运营地铁的城市地下工程施工安全韧性的方法,首先,通过对近接施工的3个方面(新建地下工程、地层、既有地下结构)以及2个维度(技术和管理)的分析,建立一个较为完整的韧性指标体系;其次,结合层次分析法、熵权法和博弈论,提出韧性指标体系的权重组合分析方法;同时,基于集对分析理论,提出研究体系复合性能Q的连续评估方法;最后,从“最大损伤”和“累计损伤”2个角度提出韧性R的综合评估计算公式,并将其应用于具体工程案例的分析。研究结果表明:1)新提出的韧性评估方法与传统的风险评估方法可以相互印证,且新的韧性评估方法考虑因素更为全面;2)提出的系统复合性能Q包含3个维度,即既有地下结构(Q_(A))、地层(Q_(B))、新建地下工程(Q_(C)),比传统的评估理论更全面;3)随着既有地下结构的动态指标限值越来越严格,系统复合性能Q的评估结果对应有所下降。 展开更多
关键词 城市地下工程 近接施工 韧性评估 集对分析法 案例分析
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L-拓扑空间中的SPC-连通性
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作者 刘生云 王小霞 王玉焕 《西南民族大学学报(自然科学版)》 CAS 2024年第2期194-198,共5页
研究了L-拓扑空间中的SPC-连通性.首先借助强半开集和强半闭集引入SPC-连通性的概念,并研究了SPC-连通性的等价刻画;其次讨论了SPC-连通性的一些性质以及证明了SPC-连通性是拓扑不变性;最后讨论了SPC-连通性与连通性之间的关系,得出:在L... 研究了L-拓扑空间中的SPC-连通性.首先借助强半开集和强半闭集引入SPC-连通性的概念,并研究了SPC-连通性的等价刻画;其次讨论了SPC-连通性的一些性质以及证明了SPC-连通性是拓扑不变性;最后讨论了SPC-连通性与连通性之间的关系,得出:在L-拓扑空间中,SPC-连通一定是连通的,反之不成立,进而丰富和完善了L-拓扑空间中的连通性理论. 展开更多
关键词 L-拓扑空间 强半开集 强半闭集 SPC-连通性
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基于改进遗传算法的直流电机双闭环调速系统控制参数整定 被引量:1
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作者 赛东 朱阔 孔祥宣 《自动化应用》 2024年第4期29-33,36,共6页
直流电机的双闭环控制被广泛应用于直流拖动系统,采用的控制器是传统的PI控制器。在工程应用中,通常采用人工整定PI控制器的参数,往往不能得到最优的控制参数。同时,许多研究采用智能群算法进行整定。针对直流电机双闭环系统的PI参数整... 直流电机的双闭环控制被广泛应用于直流拖动系统,采用的控制器是传统的PI控制器。在工程应用中,通常采用人工整定PI控制器的参数,往往不能得到最优的控制参数。同时,许多研究采用智能群算法进行整定。针对直流电机双闭环系统的PI参数整定,提出了一种基于改进遗传算法的参数整定方法。与传统遗传算法相比,改进遗传算法的整定效果更佳,具有较快的响应速度、较好的稳定性和较小的超调,更适用于对直流电机双闭环调速系统的控制参数进行整定。 展开更多
关键词 直流电机 双闭环调速系统 参数整定 改进遗传算法
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高层结构-混联Ⅱ型惯容阻尼耗能体系减震性分析
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作者 王晓琳 王善库 +1 位作者 葛新广 王昌盛 《地震工程与工程振动》 CSCD 北大核心 2024年第5期176-187,共12页
针对高层结构中设置混联Ⅱ型惯容阻尼器组成耗能体系的随机响应分析复杂的问题,提出了结构位移及阻尼器阻尼力响应的封闭解,并基于所获得的封闭解探究了实模态振型数对分析精度的影响和在原结构层间位移超限楼层设置阻尼器能有效减震的... 针对高层结构中设置混联Ⅱ型惯容阻尼器组成耗能体系的随机响应分析复杂的问题,提出了结构位移及阻尼器阻尼力响应的封闭解,并基于所获得的封闭解探究了实模态振型数对分析精度的影响和在原结构层间位移超限楼层设置阻尼器能有效减震的布置策略。首先,根据混联Ⅱ型惯容阻尼器力学构造图及设置方式,建立阻尼器阻尼力与结构节点水平位移的微分型本构关系进而重构耗能体系的地震动方程。其次,利用实模态解耦法获得高层结构简明等效的动力学参数,运用功率谱二次式分解法推导出结构节点相对于地面的绝对位移、竖向构件层间位移及阻尼器阻尼力等响应的功率谱精确二次式解进而推导出耗能体系基于双过滤白噪声激励下系列响应的0~2阶谱矩简明封闭解。最后,通过算例,验证了所提封闭解的正确性;研究了实模态振型数对系列响应谱矩分析精度的影响和阻尼器设置位置对结构减震效果的影响。研究表明:对于多自由度结构响应分析时,建议采用原结构自由振动分析时质量参与系数累计达100%时所对应的振型数,可获得稳定的精度和提高大型复杂结构设置混联Ⅱ型惯容阻尼器的响应的分析效率;通过在原结构层间位移超限楼层或连续多层层间位移超限的楼层中间隔一层设置参数合适的混联Ⅱ型惯容阻尼器可有效降低结构的地震动响应,所提惯容阻尼器设置策略具有较好的经济性。所提解析解和惯容系统在高层结构的设置策略可为混联Ⅱ型惯容阻尼器在实际工程应用中提供有益的参考价值。 展开更多
关键词 混联Ⅱ型惯容阻尼器 功率谱二次式分解法 封闭解 实模态振型数 阻尼器设置策略
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一种面向船体扫描的多站点云鲁棒配准技术
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作者 胡敏捷 杨荣淇 +1 位作者 谢洪 马琦 《计量与测试技术》 2024年第5期54-58,共5页
为实现船舱外壳的点云配准,本文提出了一种基于回环约束的多站点云配准方法。首先,使用ISS从场景中提取关键点,将颜色信息与形状信息的直方图相融合,得到船舱点云外壳的CSHOT特征描述符;然后,基于回环的粗配准,构建全连接图,并利用GROR... 为实现船舱外壳的点云配准,本文提出了一种基于回环约束的多站点云配准方法。首先,使用ISS从场景中提取关键点,将颜色信息与形状信息的直方图相融合,得到船舱点云外壳的CSHOT特征描述符;然后,基于回环的粗配准,构建全连接图,并利用GROR,结合最大一致性集约束和闭环约束移除误匹配;最后,采用全局的精配准LUM算法完成位姿优化。实验表明:该方法的平均RMSE为0.0077m,对船舱外壳的点云配准取结果较好。 展开更多
关键词 船舱外壳 CSHOT 最大一致性集约束 闭环约束 多站点云配准
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HB-Continuous Mappings in L-Topological Space
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作者 Najah A. AlSaedi 《Advances in Pure Mathematics》 2024年第5期333-353,共21页
In this paper, we introduce and study the notion of HB-closed sets in L-topological space. Then, HB-convergence theory for L-molecular nets and L-ideals is established in terms of HB-closedness. Finally, we give a new... In this paper, we introduce and study the notion of HB-closed sets in L-topological space. Then, HB-convergence theory for L-molecular nets and L-ideals is established in terms of HB-closedness. Finally, we give a new definition of fuzzy H-continuous [1] which is called HB-continuity on the basis of the notion of H-bounded L-subsets in L-topological space. Then we give characterizations and properties by making use of HB-converges theory of L-molecular nets and L-ideals. 展开更多
关键词 L-Topological Space HB-closed set H-Bounded set HB-Continuous Mappings HB-Convergence L-Molecular Nets L-Ideals
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绿色闭环供应链网络解的存在性研究
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作者 徐嘉磊 林志 《科技和产业》 2024年第11期20-27,共8页
利用变分不等式相关知识对绿色闭环供应链网络均衡条件进行研究,构建各个决策者的可行策略的集值映射,将绿色闭环供应链网络均衡问题转化为广义Nash均衡问题,结合集值映射的连续性、凸性与紧性,利用不动点定理研究绿色闭环供应链网络解... 利用变分不等式相关知识对绿色闭环供应链网络均衡条件进行研究,构建各个决策者的可行策略的集值映射,将绿色闭环供应链网络均衡问题转化为广义Nash均衡问题,结合集值映射的连续性、凸性与紧性,利用不动点定理研究绿色闭环供应链网络解的存在性与均衡条件。基于研究结论,提出绿色闭环供应链网络各层决策者对应的变分不等式以及多准则网络均衡条件和绿色闭环供应链网络解的存在性定理。 展开更多
关键词 绿色闭环供应链 广义Nash均衡 集值映射 上半连续 下半连续 拟凹性
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非理想条件下基于SAADR-PI的MMC型电力电子变压器CCS-MPC控制策略
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作者 杨浩 周建萍 +1 位作者 黄烈钢 周靖涛 《南方电网技术》 CSCD 北大核心 2024年第9期11-22,共12页
基于模块化多电平换流器(modular multilevel converter,MMC)的电力电子变压器(power electronic transformer,PET)在非理想工况下易发生故障及扰动,严重影响系统电能质量。针对传统控制方法在非理想工况下存在的动稳态性能差等问题,在M... 基于模块化多电平换流器(modular multilevel converter,MMC)的电力电子变压器(power electronic transformer,PET)在非理想工况下易发生故障及扰动,严重影响系统电能质量。针对传统控制方法在非理想工况下存在的动稳态性能差等问题,在MMC-PET整流级提出了基于自适应自抗扰比例积分控制器的连续控制集模型预测控制策略。首先,设计了自适应自抗扰比例积分控制器用于电压外环,解决了电压外环信号跟踪及扰动抑制能力差等问题。其次,电流内环使用连续控制集模型预测控制方法以提高系统的响应速度及稳态性能,引入改进型载波移相调制策略解决桥臂电流畸变问题。最后,在网侧负载突变、网压不平衡、输出级负载投入等非理想工况下对MMC-PET系统进行对比仿真和实验,验证了所提控制策略的优越性。 展开更多
关键词 电力电子变压器 模块化多电平换流器 自适应自抗扰比例积分控制 连续控制集模型预测控制 双闭环控制
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On <i>M</i>-Asymmetric Semi-Open Sets and Semicontinuous Multifunctions in Bitopological Spaces 被引量:2
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作者 Levy K. Matindih Edwin Moyo 《Advances in Pure Mathematics》 2021年第4期218-236,共19页
The purpose of this paper is to introduce the notions of <em>m</em>-asymmetric semiopen sets and <em>M</em>-asymmetric semicontinuous multifunctions defined between asymmetric sets satisfying c... The purpose of this paper is to introduce the notions of <em>m</em>-asymmetric semiopen sets and <em>M</em>-asymmetric semicontinuous multifunctions defined between asymmetric sets satisfying certain minimal conditions in the framework of bitopological spaces. Some new characterizations of <em>m</em>-asymmetric semiopen sets and <em>M</em>-asymmetric semicontinuous multifunctions will be investigated and several fundamental properties will be obtained. 展开更多
关键词 m-Spaces m-Semiasymmetric Open and closed sets Upper and Lower M-Asymmetric Semicontinuous Multifunction
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用变异FP-树改进CLOSET算法
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作者 刘迎意 吴春旭 沈陵峰 《计算机仿真》 CSCD 北大核心 2010年第3期98-101,共4页
频繁闭项集提供了频繁项集的一种完整、最小表示,对频繁闭项集的挖掘是近年来数据挖掘领域研究的热点,研究人员从不同角度对算法改进以提高算法的效率。基于频繁项集中共生项集的性质,提出无须进行子集检查的频繁闭项集挖掘方法,并设计... 频繁闭项集提供了频繁项集的一种完整、最小表示,对频繁闭项集的挖掘是近年来数据挖掘领域研究的热点,研究人员从不同角度对算法改进以提高算法的效率。基于频繁项集中共生项集的性质,提出无须进行子集检查的频繁闭项集挖掘方法,并设计一种变异的FP-树结构,利用FP-树结构来存储结点共生项集信息,以改进CLOSET算法,算法无须遍历结果集进行闭合性检查。实验表明,在支持度阈值减小,结果集变大时,改进算法的时间增长率比原有算法小。 展开更多
关键词 数据挖掘 频繁闭项集 算法改进
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An Implanted Closed-loop Chip System for Heart Rate Control:System Design and Effects in Conscious Rats 被引量:3
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作者 Yuxuan Zhou Yuan Yuan +4 位作者 Juan Gao Ling Yang Feng Zhang Guoqing Zhu Xingya Gao 《The Journal of Biomedical Research》 CAS 2010年第2期107-114,共8页
Objective: To evaluate the efficiency of an implanted chip system for the control of heart rate (HR). Methods: The HR was recorded in six conscious Sprague-Dawley (SD) rats. An implanted chip system was designed... Objective: To evaluate the efficiency of an implanted chip system for the control of heart rate (HR). Methods: The HR was recorded in six conscious Sprague-Dawley (SD) rats. An implanted chip system was designed to regulate the HR by stimulating the right cervical vagus nerve according to the feedback of real time HR. Each rat was subjected to 30-min regulation and 30-min recovery. The change of HR during the regulation period was compared with the control. The ECG was recorded during the experiment for 24 h. Results: The ECG signals were successfully recorded during the experiment. The HR was significantly decreased during the period of regulation compared with control (-79.3 ± 34.5, P 〈 0.01, n = 6) and then recovered to normal after regulation. Conclusion: The described implanted chip system can regulate the HR to a designated set point. 展开更多
关键词 closed-loop regulation implanted chip system set point heart rate vagus nerve stimulation Remote-controlled animal
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Rough similarity degree and rough close degree in rough fuzzy sets and the applications
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作者 Li Jian Xu Xiaojing Shi Kaiquan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第5期945-951,共7页
Based on rough similarity degree of rough sets and close degree of fuzzy sets, the definitions of rough similarity degree and rough close degree of rough fuzzy sets are given, which can be used to measure the similar ... Based on rough similarity degree of rough sets and close degree of fuzzy sets, the definitions of rough similarity degree and rough close degree of rough fuzzy sets are given, which can be used to measure the similar degree between two rough fuzzy sets. The properties and theorems are listed. Using the two new measures, the method of clustering in the rough fuzzy system can be obtained. After clustering, the new fuzzy sample can be recognized by the principle of maximal similarity degree. 展开更多
关键词 rough fuzzy set rough similarity degree rough close degree CLUSTERING recognition of rough pattern maximal similarity degree principle.
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Theorems of Helly's Type for Partially-closed Half-spaces
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作者 Liu Jian-Guo Guo Qi 《Communications in Mathematical Research》 CSCD 2018年第2期117-124,共8页
In this article, under quite weaker conditions, theorems of Helly’s type for(not necessarily finite) family of partially closed half-spaces are presented in both analytic and geometric forms. Examples are also provid... In this article, under quite weaker conditions, theorems of Helly’s type for(not necessarily finite) family of partially closed half-spaces are presented in both analytic and geometric forms. Examples are also provided to show that these conditions cannot be omitted in general. 展开更多
关键词 Helly's theorem partially-closed half-space affine function convex set
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A Hybrid Simulation Test Platform for Verifying the Protection Settings of SPS
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作者 Jianjian Li Luojiang Qian 《Energy and Power Engineering》 2017年第4期346-351,共6页
To verify the effectiveness and correctness of the protection settings in ring structure Shipboard Power System (SPS), a digital-physical hybrid simulation platform at China Ship Development and Design Center (CSDDC) ... To verify the effectiveness and correctness of the protection settings in ring structure Shipboard Power System (SPS), a digital-physical hybrid simulation platform at China Ship Development and Design Center (CSDDC) has been built, which aims to give double verification effect of design scheme and physical device. The platform consists of eMEGAsim digital simulator, signal power amplifiers and digital-analog interface equipments. With this platform, the multiple protection device of ring structure grid can be accessed to form a close-loop test system. Since eMEGAsim model-simulated faults and actual protection device actions are on real time, the tripping settings of each device as well as their coordinate performance between multiple devices can be verified in this close-loop test. 展开更多
关键词 Hybrid Simulation SHIPBOARD Power System (SPS) PROTECTION setTINGS Close-Loop TEST Verify
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全自动密闭式组织脱水机的应用流程探讨 被引量:1
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作者 邓桃 周胜理 孔令非 《河南医学研究》 CAS 2023年第8期1369-1373,共5页
目的 利用全自动密闭式组织脱水机的优势,规范组织脱水流程,提高组织标本脱水质量,满足诊断需要。方法 对脱水机程序改进前后的组织脱水情况及制片效果对比,探讨程序设置、试剂控制和设备清洁等对组织脱水的影响。结果 脱水程序改进前... 目的 利用全自动密闭式组织脱水机的优势,规范组织脱水流程,提高组织标本脱水质量,满足诊断需要。方法 对脱水机程序改进前后的组织脱水情况及制片效果对比,探讨程序设置、试剂控制和设备清洁等对组织脱水的影响。结果 脱水程序改进前组织蜡块发白、发硬、中心有凹陷,镜下组织切片易脆、易碎,有裂隙皱褶,红蓝对比不清晰,改进后组织蜡块软硬适中、有弹性,久放无凹陷,镜下组织切片厚薄均匀、细胞结构清晰、红蓝对比清晰。结论 改进后的组织脱水流程使标本处理标准化和规范化,组织蜡块及病理制片质量提高,满足了临床及诊断的需要。 展开更多
关键词 全自动密闭式组织脱水机 脱水流程 程序设置 试剂更换
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基于双识别器对抗的开放域自适应故障诊断方法
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作者 佘博 梁伟阁 +1 位作者 秦奋起 董海迪 《仪器仪表学报》 EI CAS CSCD 北大核心 2023年第7期325-334,共10页
领域自适应问题在机械设备故障诊断领域已被广泛研究,当前大多数封闭域自适应方法通常都假设源域和目标域共享相同的标签类型空间。然而,这不完全符合机械设备真实的诊断需求,实际上会出现新的故障类型,因而传统依据边缘分布对齐的方法... 领域自适应问题在机械设备故障诊断领域已被广泛研究,当前大多数封闭域自适应方法通常都假设源域和目标域共享相同的标签类型空间。然而,这不完全符合机械设备真实的诊断需求,实际上会出现新的故障类型,因而传统依据边缘分布对齐的方法难以处理此开放域问题,不能正确辨识出已存在的样本类型和新出现的类型。针对源域和目标域标签类型空间部分重叠的这另一典型开放域诊断问题,提出了一种基于双识别器对抗的开放域自适应故障诊断方法。两个结构相同的神经网络被引入进行对抗性训练,以增强模型对已知类型辨识的领域自适应性能,利用源域与目标域熵最大与最小化策略,以及目标域样本输出的二元交叉方案用以建立分界线隔离新出现的未知类型。利用轴承数据和自吸式离心泵数据进行分析验证,实验结果表明:所提方法相对于典型的封闭域和开放域模型,能更准确的判定机械设备已存在的故障类型和新出现的未知故障类型,在各诊断任务中,均能达到90%以上的正确率。 展开更多
关键词 封闭域 开放域 双识别器 故障诊断
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