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New Normal Control of Agricultural Non-point Source Pollution in the Dianchi Lake Basin 被引量:10
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作者 Xia Tiyuan Chen Zebin Jin Song 《Meteorological and Environmental Research》 CAS 2017年第2期63-72,共10页
Based on Kunming statistical yearbook and field survey data of agricultural non-point source pollution in counties or districts in the Dianchi Lake basin,previous and current situation of agricultural production and a... Based on Kunming statistical yearbook and field survey data of agricultural non-point source pollution in counties or districts in the Dianchi Lake basin,previous and current situation of agricultural production and agricultural non-point source pollution control in the Dianchi Lake basin were studied,and countermeasures and suggestions of comprehensive control of agricultural non-point source pollution in the basin were proposed. 展开更多
关键词 The Dianchi LAKE BASIN AGRICULTURAL non-point source POLLUTION NEW normal control Measures China
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Genomic variations in the counterpart normal controls of lung squamous cell carcinomas 被引量:2
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作者 Dalin Zhang Liwei Qu +2 位作者 Bo Zhou Guizhen Wang Guangbiao Zhou 《Frontiers of Medicine》 SCIE CAS CSCD 2018年第3期280-288,共9页
Lung squamous cell carcinoma (LUSC) causes approximately 400 000 deaths each year worldwide. The occurrence of LUSC is attributed to exposure to cigarette smoke, which induces the development of numerous genomic abn... Lung squamous cell carcinoma (LUSC) causes approximately 400 000 deaths each year worldwide. The occurrence of LUSC is attributed to exposure to cigarette smoke, which induces the development of numerous genomic abnormalities. However, few studies have investigated the genomic variations that occur only in normal tissues that have been similarly exposed to tobacco smoke as tumor tissues. In this study, we sequenced the whole genomes of three normal lung tissue samples and their paired adjacent squamous cell carcinomas. We then called genomic variations specific to the normal lung tissues through filtering the genomic sequence of the normal lung tissues against that of the paired tumors, the reference human genome, the dbSNP138 common germline variants, and the variations derived from sequencing artifacts. To expand these observations, the whole exome sequences of 478 counterpart normal controls (CNCs) and paired LUSCs of The Cancer Genome Atlas (TCGA) dataset were analyzed. Sixteen genomic variations were called in the three normal lung tissues. These variations were confirmed by Sanger capillary sequencing. A mean of 0.5661 exonic variations/Mb and 7.7887 altered genes per sample were identified in the CNC genome sequences of TCGA. In these CNCs, C:G→T:A transitions, which are the genomic signatures of tobacco carcinogen N-methyl-N-nitro-N-nitrosoguanidine, were the predominant nucleotide changes. Twenty five genes in CNCs had a variation rate that exceeded 2%, including ARSD (18.62%), MUC4 (8.79%), and RBMX(7.11%). CNC variations in CTAGE5 and USP17L7were associated with the poor prognosis of patients with LUSC. Our results uncovered previously unreported genomic variations in CNCs, rather than LUSCs, that may be involved in the develooment of LUSC. 展开更多
关键词 lung cancer counterpart normal control genomic variations
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A REVERSED-FRAME NORMALIZATION DESIGN OF ROBUST FLIGHT CONTROL SYSTEM
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作者 Jiang Changsheng, Shen Chunlin and Hu ZhonghanNanjing Aeronautical Institute 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1991年第1期35-45,共11页
In this paper, a discussion is devoted to the theory and method of a reversed-frame normalization design to robust flight control system. The robust stability theory of the normal transfer function matrix with the sam... In this paper, a discussion is devoted to the theory and method of a reversed-frame normalization design to robust flight control system. The robust stability theory of the normal transfer function matrix with the same characteristic gain loci is proved. An example of flight control system design shows the application and advantage of this method. 展开更多
关键词 A REVERSED-FRAME normalIZATION DESIGN OF ROBUST FLIGHT control SYSTEM
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Role of Soluble Factors in Immune and Normal Sera in the Control of Giardiasis Due to Giardia Iamblia
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作者 R.K.SRIVASTAVA N.SETHI +1 位作者 N.GUPTA A.K.AGARWAL 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1992年第2期87-91,共5页
Hyperimmune sera (HIS), raised against crude giardia antigen, on in vitro interaction, caused more agglutination of Giardia lamblia trophozoites. Heat inactivated HIS possessed a comparable agglutinating activity as t... Hyperimmune sera (HIS), raised against crude giardia antigen, on in vitro interaction, caused more agglutination of Giardia lamblia trophozoites. Heat inactivated HIS possessed a comparable agglutinating activity as the non-inactivated controls. Non-inactivated normal (unimmunized) serum caused immobilization of Giardia trophozoite, which was checked on heat inactivation. Antibodies in immune sera are mainly responsible for agglutination, whereas the heat labile non-immune components control the mobility of the intestinal parasite. 展开更多
关键词 Role of Soluble Factors in Immune and normal Sera in the control of Giardiasis Due to Giardia Iamblia
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基于Normal Form方法的电机系统分岔控制 被引量:1
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作者 袁惠群 张中华 《振动.测试与诊断》 EI CSCD 北大核心 2014年第6期1084-1087,1171,共4页
研究了无刷直流电机系统等效非线性数学模型,分析了系统的Hopf分岔行为,并设计了washout滤波器,对系统产生的分岔行为进行控制。引入直接Normal Form(规范型)计算方法,求出系统的Hopf分岔规范式。通过规范式系数讨论控制参数的选择原则... 研究了无刷直流电机系统等效非线性数学模型,分析了系统的Hopf分岔行为,并设计了washout滤波器,对系统产生的分岔行为进行控制。引入直接Normal Form(规范型)计算方法,求出系统的Hopf分岔规范式。通过规范式系数讨论控制参数的选择原则以及对Hopf分岔类型及极限环幅值的影响。理论和仿真结果表明:在施加控制器之前,系统发生亚临界Hopf分岔,极限环不稳定,系统进入混沌状态;在施加控制器之后,当受控系统规范式系数实部小于零时,系统发生超临界Hopf分岔,原系统不稳定极限环被控制为稳定极限环,从而抑制了混沌的产生,保证了电机运行性能的稳定性。 展开更多
关键词 无刷直流电机 HOPF分岔 washout滤波器 规范型 分岔控制
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基于Normal Form方法的UPFC多个功能控制器间交互影响分析 被引量:3
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作者 邹振宇 江全元 +1 位作者 曹一家 王海风 《现代电力》 2005年第5期1-6,共6页
统一潮流控制器(UPFC)的重要特点之一就是它具有的多控制功能,包括潮流控制、电压控制和稳定性控制等等。然而时域仿真研究表明统一潮流控制器的多个控制器之间可能存在着较强的交互影响。本文研究了规范型(Normal Form)方法用于分析UPF... 统一潮流控制器(UPFC)的重要特点之一就是它具有的多控制功能,包括潮流控制、电压控制和稳定性控制等等。然而时域仿真研究表明统一潮流控制器的多个控制器之间可能存在着较强的交互影响。本文研究了规范型(Normal Form)方法用于分析UPFC控制器间的交互影响问题的可能性,并引入一非线性交互指标定量地指示出控制器间的交互强弱程度。所提方法应用到新英格兰10机39节点系统,并通过时域仿真验证了所提规范型理论分析方法的有效性。 展开更多
关键词 统一潮流控制器 多控制通道 交互影响 规范型 非线性交互指标
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基于两点应变测量对变截面弹性杆的正向波抵消研究
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作者 吕超勇 于涛 +1 位作者 侯文朝 赵翼飞 《机械工程师》 2026年第3期43-46,共4页
为了减少力波扰动造成的危害,采用两点应变法测量对变截面弹性杆中的正向波进行分离,并设计一种前馈控制系统对正向波进行抵消。由于弥散效应的影响,各谐波分量按各自的相速传播,导致波形发生变化,从而无法直接对变截面弹性杆中的力波... 为了减少力波扰动造成的危害,采用两点应变法测量对变截面弹性杆中的正向波进行分离,并设计一种前馈控制系统对正向波进行抵消。由于弥散效应的影响,各谐波分量按各自的相速传播,导致波形发生变化,从而无法直接对变截面弹性杆中的力波直接正向分离,因此需要对测量方法进行改进,再将各谐波分离,该方法基于变截面杆的传播方程,对不同频率分量采用不同的传递方程,从而预测至下游的正向扰动,并设计一种理想的前馈控制系统以抵消正向波。通过有限元仿真模拟将计算数据代入前馈系统,结果表明可以达到理想消振效果。 展开更多
关键词 变截面 弥散效应 前馈控制 法向力
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基于TDLAS的氨痕量气体传感器设计
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作者 李延玲 游源 +2 位作者 钱枫 邓明星 崔蕊 《电子设计工程》 2026年第6期96-102,108,共8页
现有的氨痕量气体传感器在检测精度、灵敏度、工作稳定性和微型化方面仍有很大提升空间,文中应用TDLAS-WMS原理开发出一种氨痕量气体传感器。为提升传感器检测性能,设计了增量式PID算法实现激光器的恒温控制,以确保激光波长的精确调谐... 现有的氨痕量气体传感器在检测精度、灵敏度、工作稳定性和微型化方面仍有很大提升空间,文中应用TDLAS-WMS原理开发出一种氨痕量气体传感器。为提升传感器检测性能,设计了增量式PID算法实现激光器的恒温控制,以确保激光波长的精确调谐。此外,将鹈鹕优化算法(POA)和变分模态分解(VMD)进行融合用于数字滤波,与硬件滤波电路共同作用,以降低信号噪声。通过配置不同浓度的氨气进行谐波检测,并对得到的二次谐波进行光强归一化,以消除光强变化对检测精度的影响,最后采用分段拟合标定法进行浓度标定。实验结果表明,该传感器的检测灵敏度为3.73×10-3,测量最大误差仅为2.21%,可以满足氨痕量气体的实时监测需求。 展开更多
关键词 激光吸收光谱技术 激光器温度控制 数字滤波 光强归一化
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用Normal Form直接法研究壁板的热颤振与控制 被引量:2
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作者 赵秀芳 曹树谦 《振动与冲击》 EI CSCD 北大核心 2012年第11期54-56,共3页
建立了二维受热壁板在超音速气流中的颤振方程。运用分岔理论求得了系统的Hopf分岔点,应用Nor-mal Form直接法计算得到系统Hopf分岔Normal Form系数。引入wash-out滤波器技术对壁板热颤振进行了主动控制,延迟系统Hopf分岔的产生而不改... 建立了二维受热壁板在超音速气流中的颤振方程。运用分岔理论求得了系统的Hopf分岔点,应用Nor-mal Form直接法计算得到系统Hopf分岔Normal Form系数。引入wash-out滤波器技术对壁板热颤振进行了主动控制,延迟系统Hopf分岔的产生而不改变分岔类型。最后采用数值模拟验证了理论分析。 展开更多
关键词 热颤振 HOPF分岔 normal Form直接法 控制
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基于数据挖掘算法的配电网全过程造价控制方法研究
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作者 陈付雷 李建青 施晓敏 《电子设计工程》 2026年第5期106-110,116,共6页
从全过程的角度分析,影响配电网造价的因素较多,且影响程度不同。为此,提出基于数据挖掘算法的配电网全过程造价控制方法。该方法分别从设计阶段、施工过程、材料设备采购三个方面,分析配电网全过程造价的影响因素构成,采用两两比较的... 从全过程的角度分析,影响配电网造价的因素较多,且影响程度不同。为此,提出基于数据挖掘算法的配电网全过程造价控制方法。该方法分别从设计阶段、施工过程、材料设备采购三个方面,分析配电网全过程造价的影响因素构成,采用两两比较的方式构建配电网全过程造价影响因素的判断矩阵,对其进行归一化处理,结合最大特征根参量为影响因素赋权。在控制阶段,采用层次分析法构建分层控制目标体系,包括总体控制目标、子控制目标、控制阶段目标与控制指标。将敏感系数趋近于0的影响因素状态作为最终控制结果,以降低其对造价的扰动。实验结果显示,设计控制方法下的单位投资成本明显低于对照组。 展开更多
关键词 数据挖掘算法 配电网全过程 造价控制 判断矩阵 归一化处理 最大特征根 敏感系数
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Infection Prevention Strategy in General Hospital under Regular Epidemic Prevention and Control 被引量:1
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作者 Yuanli Chen Ying Xue +2 位作者 Yingying Zhang Huijun Zhou Liang Peng 《Open Journal of Preventive Medicine》 2021年第4期159-167,共9页
New coronavirus pneumonia spread rapidly all over the world in the first half of 2020, which is a new respiratory disease with strong infectiousness. At present, the epidemic situation in China has been effectively co... New coronavirus pneumonia spread rapidly all over the world in the first half of 2020, which is a new respiratory disease with strong infectiousness. At present, the epidemic situation in China has been effectively controlled, but the global epidemic situation remains grim, and the National Health Commission has instructed that the prevention and control of new coronavirus pneumonia should become normalized. As outposts for surveillance of public health events, hospitals are an important front in the fight against the epidemic. Therefore, it is very crucial to construct infection prevention and control system actively to contain the outbreak. This paper analyzes and summarizes the normal prevention and control management strategy of Infection Control Branch Management (hereinafter referred to as Hospital Infection-Control Dept) in a certain designated comprehensive third-grade hospital in Guangdong Province and transforms the prevention and control means in emergency state into measures for sustainable development, which also provides basis and reference for Hospital Infection-Control Dept of medical institutions to formulate prevention and control guidelines. 展开更多
关键词 normal Prevention and control Hospital Infection Management Infection Prevention Strategy
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日常检测结果应用于实验室质量管理的探析
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作者 宋飞 黄平 +4 位作者 史高兴 管嵩 万敏 岳振艺 冯丽丽 《云南化工》 2026年第3期83-86,共4页
通过日常检测结果的积累统计,进行实验室质量管理评价。以铁矿石中全铁含量的检测为例,通过累积的日常样品检测结果计算测量精密度,用于评价检测人员持续能力。以质控样检测结果计算期间精密度,验证整个检测过程的独立性和正态性,确保... 通过日常检测结果的积累统计,进行实验室质量管理评价。以铁矿石中全铁含量的检测为例,通过累积的日常样品检测结果计算测量精密度,用于评价检测人员持续能力。以质控样检测结果计算期间精密度,验证整个检测过程的独立性和正态性,确保测量过程处于统计控制状态。 展开更多
关键词 质量管理 日常检测 质控样 期间精密度 独立性和正态性
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Discrete-time Direct Model Reference Adaptive Control: A Systematic Approach 被引量:1
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作者 LI Jun-Ling XIE Xue-Jun 《自动化学报》 EI CSCD 北大核心 2007年第10期1048-1052,共5页
为直接模型引用的分离时间的系统,设计和分析的一个类,有规范的适应法律的适应控制(MRAC ) 被调查。我们责骂在输入和产量之间的 p 和 2 个关系性质上的分离时间的结论,和分离时间的交换词根 1 和 2。我们也建立分离时间的适应法律... 为直接模型引用的分离时间的系统,设计和分析的一个类,有规范的适应法律的适应控制(MRAC ) 被调查。我们责骂在输入和产量之间的 p 和 2 个关系性质上的分离时间的结论,和分离时间的交换词根 1 和 2。我们也建立分离时间的适应法律的性质,定义使正常化的信号,并且联系有在靠近环的系统的所有信号的信号。因此,分离时间的 MRAC 计划的稳定性和集中性质作为在连续时间的案例中以一种系统的方式严厉地被分析。 展开更多
关键词 离散时间系统 控制系统 系统方法 交换引理 模型参考自适应
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A Systematic Analysis Approach to Discrete-time Indirect Model Reference Adaptive Control 被引量:1
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作者 XIE Xue-Jun LI Jun-Ling 《自动化学报》 EI CSCD 北大核心 2007年第11期1170-1175,共6页
这份报纸论述间接模型引用的设计和分析有为分离时间的系统的一个类的规范的适应法律的适应控制(MRAC ) 。主要工作包括三部分。第一,构造工厂参数评价算法不仅拥有传统的评价算法的象那些的一样的性质而且在零避免分割的可能性。第二... 这份报纸论述间接模型引用的设计和分析有为分离时间的系统的一个类的规范的适应法律的适应控制(MRAC ) 。主要工作包括三部分。第一,构造工厂参数评价算法不仅拥有传统的评价算法的象那些的一样的性质而且在零避免分割的可能性。第二,由发现在工厂参数之间的关系,估计和控制器参数估计并且用工厂参数的性质估计,控制器参数估计的类似的性质也被建立。第三,基于关系,在使正常化之间的性质发信号并且在靠近环的系统并且在分离时间的系统上的一些重要数学工具上的所有信号作为在连续时间的盒子中,到分离间接 MRAC 计划的系统的稳定性和集中分析途径严厉地被开发。 展开更多
关键词 模型参考自适应控制 不连续时间系统 标准化适应定律 系统分析
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Robust adaptive output stabilization using dynamic normalizing signal
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作者 Haixia SU Xuejun XIE Haikuan LIU 《控制理论与应用(英文版)》 EI 2007年第1期89-93,共5页
For a class of nonlinear systems with dynamic uncertainties, robust adaptive stabilization problem is considered in this paper. Firstly, by introducing an observer, an augmented system is obtained. Based on the system... For a class of nonlinear systems with dynamic uncertainties, robust adaptive stabilization problem is considered in this paper. Firstly, by introducing an observer, an augmented system is obtained. Based on the system, we construct an exp-ISpS Lyapunov function for the unmodeled dynamics, prove that the unmodeled dynamics is exp-ISpS, and then obtain a dynamic normalizing signal to counteract the dynamic disturbances. By the backstepping technique, an adaptive controller is given, it is proved that all the signals in the adaptive control system are globally uniformly ultimately bounded, and the output can be regulated to the origin with any prescribed accuracy. A simulation example further demonstrates the efficiency of the control scheme. 展开更多
关键词 Unmodeled dynamics Exp-ISpS Dynamic normalizing signal BACKSTEPPING Adaptive control
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Suppression of oscillatory congestion via trunk link bandwidth and control gain in star network 被引量:1
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作者 Sainan WANG Shu ZHANG Jian XU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2019年第1期25-48,共24页
The time delay-induced instability in an Internet congestion control model is investigated. The star topology is considered, and the link bandwidth ratio and the control gain are selected as the tunable parameters for... The time delay-induced instability in an Internet congestion control model is investigated. The star topology is considered, and the link bandwidth ratio and the control gain are selected as the tunable parameters for congestion suppression. The stability switch boundary is obtained by the eigenvalue analysis for the linearized system around the equilibrium. To investigate the oscillatory congestion when the equilibrium becomes unstable, the center manifold reduction and the normal form theory are used to study the periodic oscillation induced by the delay. The theoretical analysis and numerical simulation show that the ratio between bandwidths of the trunk link and the regular link,rather than these bandwidths themselves, is crucial for the stability of the congestion control system. The present results demonstrate that it is not always effective to increase the link bandwidth ratio for stabilizing the system, and for some certain delays, adjusting the control gain is more efficient. 展开更多
关键词 Internet CONGESTION control HOPF BIFURCATION DELAYED differential equation stability normal form
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Robust Radiometric Normalization of the near Equatorial Satellite Images Using Feature Extraction and Remote Sensing Analysis 被引量:1
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作者 Hayder Dibs Shattri Mansor +1 位作者 Noordin Ahmad Nadhir Al-Ansari 《Engineering(科研)》 CAS 2023年第2期75-89,共15页
Relative radiometric normalization (RRN) minimizes radiometric differences among images caused by inconsistencies of acquisition conditions rather than changes in surface. Scale invariant feature transform (SIFT) has ... Relative radiometric normalization (RRN) minimizes radiometric differences among images caused by inconsistencies of acquisition conditions rather than changes in surface. Scale invariant feature transform (SIFT) has the ability to automatically extract control points (CPs) and is commonly used for remote sensing images. However, its results are mostly inaccurate and sometimes contain incorrect matching caused by generating a small number of false CP pairs. These CP pairs have high false alarm matching. This paper presents a modified method to improve the performance of SIFT CPs matching by applying sum of absolute difference (SAD) in a different manner for the new optical satellite generation called near-equatorial orbit satellite and multi-sensor images. The proposed method, which has a significantly high rate of correct matches, improves CP matching. The data in this study were obtained from the RazakSAT satellite a new near equatorial satellite system. The proposed method involves six steps: 1) data reduction, 2) applying the SIFT to automatically extract CPs, 3) refining CPs matching by using SAD algorithm with empirical threshold, and 4) calculation of true CPs intensity values over all image’ bands, 5) preforming a linear regression model between the intensity values of CPs locate in reverence and sensed image’ bands, 6) Relative radiometric normalization conducting using regression transformation functions. Different thresholds have experimentally tested and used in conducting this study (50 and 70), by followed the proposed method, and it removed the false extracted SIFT CPs to be from 775, 1125, 883, 804, 883 and 681 false pairs to 342, 424, 547, 706, 547, and 469 corrected and matched pairs, respectively. 展开更多
关键词 Relative Radiometric normalization Scale Invariant Feature Transform Automatically Extraction control Points Sum of Absolute Difference
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常态化防控前后院内MDRO感染变化趋势分析
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作者 张方方 吴晓琴 +2 位作者 罗小虎 薛艳梅 刘梅 《临床医学研究与实践》 2025年第2期21-24,共4页
目的探讨常态化防控前后院内多重耐药菌(MDRO)感染变化趋势,为医院采取科学、规范的MDRO防控措施提供参考依据。方法收集2017—2022年住院患者送检标本MDRO中特定菌株检出数量、种类及感染情况等临床资料,分析常态化防控前、后MDRO感染... 目的探讨常态化防控前后院内多重耐药菌(MDRO)感染变化趋势,为医院采取科学、规范的MDRO防控措施提供参考依据。方法收集2017—2022年住院患者送检标本MDRO中特定菌株检出数量、种类及感染情况等临床资料,分析常态化防控前、后MDRO感染情况。结果常态化防控前、后,MDRO特定菌株检出率分别为12.940%、15.745%,常态化防控后的MDRO特定菌株检出率高于常态化防控前,差异具有统计学意义(P<0.05);常态化防控前、后,MDRO特定菌株医院感染率分别为0.066%、0.072%,常态化防控前、后的MDRO特定菌株医院感染率比较,差异无统计学意义(P>0.05)。常态化防控后,耐碳青霉烯类铜绿假单胞菌(CR-PA)、耐碳青霉烯类鲍曼不动杆菌(CR-AB)的检出率均高于常态化防控前,差异具有统计学意义(P<0.05);常态化防控前、后,耐甲氧西林金黄色葡萄球菌(MRSA)、耐碳青霉烯肠杆菌科细菌(CRE)的检出率比较,差异无统计学意义(P>0.05);常态化防控后,MRSA、CRE的医院感染率略低于常态化防控前,CRAB医院感染率略高于常态化防控前,CR-PA的医院感染率未发生变化。常态化防控后,手术部位感染占比低于常态化防控前,差异具有统计学意义(P<0.05)。结论常态化防控可降低手术部位的感染率,但对于MDRO感染的精准防控仍存在一定的局限。 展开更多
关键词 多重耐药菌 常态化防控 特定菌株
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基于参数归一的机器人动力学参数辨识与控制
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作者 胡明 姚中帅 +1 位作者 杨景 张立建 《机械设计与制造》 北大核心 2025年第11期322-326,共5页
工业机器人作为智能制造的重要载体,通过构建精准的动力学模型是提升其动态性能的基础,而机器人动力学模型的精度依赖于机器人连杆的运动学参数和连杆惯性参数辨识的精度。这里针对动力学模型的参数辨识问题,首先,利用牛顿欧拉方法建立... 工业机器人作为智能制造的重要载体,通过构建精准的动力学模型是提升其动态性能的基础,而机器人动力学模型的精度依赖于机器人连杆的运动学参数和连杆惯性参数辨识的精度。这里针对动力学模型的参数辨识问题,首先,利用牛顿欧拉方法建立机器人动力学方程,并基于参数归一化确定最优的辨识参数集。其次,根据观测矩阵的条件数作为优化准则,配合机器人实际物理约束及MATLAB非线性优化方法得出最优化的五阶傅里叶级数关节激励轨迹,利用最小二乘法对动力学参数进行辨识。最后,结合动力学力矩驱动的阻抗控制方式对工业机器人的动力学控制进行实验研究,进一步证明动力学参数辨识的正确性以及该控制方式的有效性、柔顺性。该研究内容为后续实现精准的力位柔顺控制奠定基础。 展开更多
关键词 工业机器人力交互 动力学模型 参数辨识 参数归一 阻抗控制 力位柔顺控制
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Flutter Control of a Two-dimensional Airfoil Using Wash-out Filter Technique 被引量:3
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作者 丁千 王冬立 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2005年第2期130-137,共8页
The wash-out filter (WF) technique is used to control the flutter of a two dimensional airfoil with cubic non-linearity in incompressible flow. Firstly, Hopf bifurcation theory is used to determine the point at whic... The wash-out filter (WF) technique is used to control the flutter of a two dimensional airfoil with cubic non-linearity in incompressible flow. Firstly, Hopf bifurcation theory is used to determine the point at which the nonlinear controller is introduced. The system is then transformed into Jordan canonical form, based on analysis of linearized eigenvalues of the system. Secondly, for the introduced WF controller, the linear control gain is determined according to Hopf bifurcation condition. The sym- bolic computing program of normal form direct method (NFDM) is also used to obtain the normal form of the controlled system. The non-linear control gain can be determined based on the relation of the type of bifurcation and the parameters of the normal form, to transform sub-critical Hopf bifurcation to be su- per-critical one. Lastly, numerical simulations are used to certify the validity of theoretical analysis, in which the amplitude of flutter or limit cycle of the controlled system is reduced greatly, comparing to the original system. 展开更多
关键词 nonlinear airfoil flutter control wash-out filter (WF) Hopf bifurcation normal form direct method (NFDM)
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