检索结果-南通市图书馆

Consistency and Asymptotic Normality of the Maximum Quasi-likelihood Estimator in Quasi-likelihood Nonlinear Models with Random Regressors

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2010年第2期26卷 241-250页

作者： tian xia Shun-fang Wang Xue-ren Wang Department of Statistics Yunnan University Kunming 650091 China School of Information Science and Engineering Yunnan University Kunming 650091 China

This paper proposes some regularity conditions, which result in the existence, strong consistency and asymptotic normality of maximum quasi-likelihood estimator （MQLE） in quasi-likelihood nonlinear models （QLNM） with random regressors. The asymptotic results of generalized linear models （GLM） with random regressors are generalized to QLNM with random regressors.

关键词： Asymptotic normality consistency maximum quasi-likelihood estimator quasi-likelihood nonlinear models with random regressors

Fuzzy Chaos Control for Vehicle Lateral Dynamics Based on Active Suspension System

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第4期27卷 793-801页

作者： HUANG Chen CHEN Long JIANG Haobin YUAN Chaochun xia tian School of Automobile and Traffic Engineering Jiangsu University

The existing research of the active suspension system（ASS） mainly focuses on the different evaluation indexes and control strategies. Among the different components, the nonlinear characteristics of practical systems and control are usually not considered for vehicle lateral dynamics. But the vehicle model has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, the nonlinear dynamic model of lateral system is considered and also the adaptive neural network of tire is introduced. By nonlinear analysis methods, such as the bifurcation diagram and Lyapunov exponent, it has shown that the lateral dynamics exhibits complicated motions with the forward speed. Then, a fuzzy control method is applied to the lateral system aiming to convert chaos into periodic motion using the linear-state feedback of an available lateral force with changing tire load. Finally, the rapid control prototyping is built to conduct the real vehicle test. By comparison of time response diagram, phase portraits and Lyapunov exponents at different work conditions, the results on step input and S-shaped road indicate that the slip angle and yaw velocity of lateral dynamics enter into stable domain and the results of test are consistent to the simulation and verified the correctness of simulation. And the Lyapunov exponents of the closed-loop system are becoming from positive to negative. This research proposes a fuzzy control method which has sufficient suppress chaotic motions as an effective active suspension system.

关键词： chaos control fuzzy active suspension system vehicle lateral dynamics

Floating Clamping Mechanism of PT Fuel Injector and Its Dynamic Characteristics Analysis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2012年第3期25卷 550-556页

作者： WANG Xinqing LIANG Sheng xia tian WANG Dong QIAN Shuhua Engineering Institute of Engineering Corps University of Science&Technology of Chinese People's Liberation ArmyNanjing 210007China Bureau of Navy Engineering Design&Research Beijing 100841China

PT fuel injector is one of the most important parts of modern diesel *** satisfy the requirements of the rapid and accurate test of PT fuel injector,the self-adaptive floating clamping mechanism was developed and used in the relevant *** dynamic characteristics directly influence the test efficiency and ***,due to its special structure and complex oil pressure signal,related documents for evaluating dynamic characteristics of this mechanism are lack and some dynamic characteristics of this mechanism can＇t be extracted and recognized effectively by traditional *** at the problem above-mentioned,a new method based on Hilbert-Huang transform（HHT） is ***,combining with the actual working process,the dynamic liquid pressure signal of the mechanism is *** analyzing the pressure fluctuation during the whole working process in time domain,oil leakage and hydraulic shock in the clamping chamber are ***,owing to the nonlinearity and nonstationarity of pressure signal,empirical mode decomposition is used,and the signal is decomposed and reconstructed into forced vibration,free vibration and *** analyzing forced vibration in the time domain,machining error and installation error of cam are ***,free vibration component is analyzed in time-frequency domain with HHT,the traits of free vibration in the time-frequency domain are *** with traditional methods,Hilbert spectrum has higher time-frequency resolutions and higher *** improved mechanism based on the above analyses can guarantee the test accuracy of injector *** new method based on the analyses of the pressure signal and combined with HHT can provide scientific basis for evaluation,design improvement of the mechanism,and give references for dynamic characteristics analysis of the hydraulic system in the interrelated fields.

关键词： PT fuel injector floating clamping mechanism dynamic characteristics analysis Hilbert-Huang transform

类风湿性关节炎与骨质疏松症和骨密度关系的孟德尔随机化分析

在线全文

学校读者我要写书评

暂无评论

中国组织工程研究 2024年第23期28卷 3715-3721页

作者：武瑞骐周毅夏天张驰杨启培张璇张亚忠崔伟广西中医药大学附属瑞康医院广西壮族自治区南宁市530000 广西中医药大学广西壮族自治区南宁市530299 梧州市中医医院骨科广西壮族自治区梧州市543000

背景:许多临床研究观察表明类风湿性关节炎与骨质疏松症和骨密度之间存在密切关系,但类风湿性关节炎与骨质疏松症和骨密度之间是否存在因果遗传尚不清楚。目的:采用两样本孟德尔随机化研究方法评估类风湿性关节炎与骨质疏松症和骨密度... 详细信息

背景:许多临床研究观察表明类风湿性关节炎与骨质疏松症和骨密度之间存在密切关系,但类风湿性关节炎与骨质疏松症和骨密度之间是否存在因果遗传尚不清楚。目的:采用两样本孟德尔随机化研究方法评估类风湿性关节炎与骨质疏松症和骨密度之间潜在的因果关系,从遗传学的角度对潜在的机制提供有意义的见解,为早期预防骨质疏松症、改善疾病的发生发展提供参考。方法:从全基因组关联研究(GWAS)公开数据库中筛选出与类风湿性关节炎相关的(P<5×10^(-8))单核苷酸多态性位点作为工具变量。研究结局主要包括骨质疏松症、5个不同部位的骨密度,包括全身骨密度、腰椎骨密度、股骨颈骨密度、足跟骨密度以及前臂骨密度。逆方差加权法为该研究评估因果效应的主要分析方法,文章采用加权中位数法、简单中位数法、加权中值方法和MR-Egger回归用于补充说明,以比值比(OR)和95%可信区间(95%CI)评价类风湿性关节炎与骨质疏松症及骨密度风险之间的因果关系,使用类风湿性关节炎Cochran’s Q检验异质性,利用MR-Egger-intercept检验是否存在水平多效性。结果与结论:①逆方差加权法结果表明遗传预测的类风湿性关节炎与骨质疏松症呈正相关(OR=1.123,95%CI:1.077-1.171,P=4.02×10^(-8)),异质性检验表明单核苷酸多态性位点不存在异质性(P=0.388),MR-Egger-intercept检验未检测到水平多效性(P=0.571),敏感性分析显示研究结果没有产生偏倚。②类风湿性关节炎与5个部位的骨密度之间不存在因果关系显示如下:全身骨密度(OR=1.000,95%CI:0.988-1.012,P=0.925)、腰椎骨密度(OR=0.999,95%CI:0.982-1.016,P=0.937)、股骨颈骨密度(OR=1.001,95%CI:0.986-1.016,P=0.866)、足跟骨密度(OR=0.996,95%CI:0.989-1.004,P=0.419)、前臂骨密度(OR=1.063,95%CI:0.970-1.031,P=0.996)。MR-Egger-intercept分析未检测到潜在的水平多效性(全身骨密度:P=0.253;腰椎骨密度:P=0.638;股骨颈骨密度:P=0.553;足跟骨密度:P=0.444;前臂骨密度:P=0.079)。③类风湿性关节炎可能通过慢性炎症与骨的形成、骨溶解和吸收之间的相互作用导致骨质疏松症,此外,糖皮质激素的使用和类风湿性关节炎患者身体内的自身抗体(如抗瓜氨酸蛋白抗体)阳性也与骨质疏松症存在相关性。④未来研究需重点关注类风湿性关节炎患者全身免疫水平的系统性炎症指标、糖皮质激素的规范使用以及定期进行骨质疏松症风险筛查。

关键词：骨质疏松症类风湿性关节炎骨密度孟德尔随机化单核苷酸多态性因果关联全基因组关联研究工具变量

在线全文

学校读者我要写书评

暂无评论

变电站事故照明自投装置及其应用

中国照明电器 2024年第4期 104-106页

作者：朱泽谦毋恒先夏天上海送变电工程有限公司上海200235

文章通过对变电站事故照明自投装置开展系统性研究,旨在为变电站的事故应急管理提供一套高效、智能的解决方案,以期在确保变电站安全运行的同时,为电力系统的智能化管理和应急响应能力的提升贡献力量。

关键词：变电站电力系统事故照明自投装置

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

中医药治疗反复胚胎种植失败的现代研究进展

天津中医药 2024年第5期41卷 668-671页

作者：吴春蕾马赛花夏天天津中医药大学第一附属医院天津300193 国家中医针灸临床医学研究中心天津300193

反复胚胎种植失败(RIF)是当今生殖医学研究的热点和难点问题,通过中医药辨证论治,取得较好疗效。文章将中医对RIF的认识从病因病机、中药及针灸治法方面进行梳理,总结RIF的主要病机为“本虚标实”,治法上补虚泻实,治疗上针药并用。现将... 详细信息

反复胚胎种植失败(RIF)是当今生殖医学研究的热点和难点问题,通过中医药辨证论治,取得较好疗效。文章将中医对RIF的认识从病因病机、中药及针灸治法方面进行梳理,总结RIF的主要病机为“本虚标实”,治法上补虚泻实,治疗上针药并用。现将近年来中医认识、治疗该病的相关文献综述如下,为今后RIF的治疗提供更多思路。

关键词：中医药反复胚胎种植失败本虚标实

RGS22 maintains the physiological function of ependymal cells to prevent hydrocephalus

在线全文

学校读者我要写书评

暂无评论

Science China Life Sciences 2024年

作者： Xue Pang Lin Gu Qiu-Ying Han Jia-Qing Xing Ming Zhao Shao-Yi Huang Jun-Xi Yi Jie Pan Hao Hong Wen Xue Xue-Qing Zhou Zhi-Hui Su Xin-Ran Zhang Li-Ming Sun Shao-Zhen Jiang Dan Luo Ling Chen Zheng-Jie Wang Yu Yu tian xia Xue-Min Zhang Ai-Ling Li Tao Zhou Hong Cai Tao Li Nanhu Laboratory National Center of Biomedical Analysis School of Basic Medical Sciences Fudan University Department of Basic Medical Sciences School of Medicine Tsinghua University

Ependymal cells line the wall of cerebral ventricles and ensure the unidirectional cerebrospinal fluid （CSF） flow by beating their motile cilia coordinately. The ependymal denudation or ciliary dysfunction causes hydrocephalus. Here, we report that the deficiency of regulator of Gprotein signaling 22 （RGS22） results in severe congenital hydrocephalus in both mice and rats. Interestingly, RGS22 is specifically expressed in ependymal cells within the brain. Using conditional knock-out mice, we further demonstrate that the deletion of Rgs22 exclusively in nervous system is sufficient to induce hydrocephalus. Mechanistically, we show that Rgs22 deficiency leads to the ependymal denudation and impaired ciliogenesis. This phenomenon can be attributed to the excessive activation of lysophosphatidic acid receptor （LPAR） signaling under Rgs22–/–condition, as the LPAR blockade effectively alleviates hydrocephalus in Rgs22–/–rats. Therefore, our findings unveil a previously unrecognized role of RGS22 in the central nervous system, and present RGS22 as a potential diagnostic and therapeutic target for hydrocephalus.

关键词：

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

自我超越在癌症患者中应用的范围综述

中华现代护理杂志 2024年第6期30卷 825-831页

作者：王峥田霞黄咏琪肖文莉广州中医药大学护理学院广州510006

目的:对自我超越在癌症患者中的相关研究进行范围审查,分析和总结自我超越在癌症患者中的研究现状,为其在今后癌症领域的发展提供一定参考。方法:系统检索中国知网、万方数据库、维普数据库、PubMed、Web of Science、Embase、Cochrane ... 详细信息

目的:对自我超越在癌症患者中的相关研究进行范围审查,分析和总结自我超越在癌症患者中的研究现状,为其在今后癌症领域的发展提供一定参考。方法:系统检索中国知网、万方数据库、维普数据库、PubMed、Web of Science、Embase、Cochrane Library及CINAHL中的相关研究,检索时限为建库至2023年9月5日,并对纳入的文献进行汇总与分析。结果:共纳入43篇文献,包括横断面调查16篇、质性研究8篇及干预性研究19篇。从理论衍变与发展、评估工具、现状及影响因素、实现途径、干预方案特征5个方面进行阐述和总结。结论:癌症患者自我超越的研究方兴未艾,未来需加强对癌症患者自我超越水平评估工具的研制,采用多种研究方法全面了解癌症患者自我超越水平及心理体验的变化,提高癌症患者自我超越干预方案的科学性和严谨性。

关键词：综述自我超越癌症患者范围审查

Strong Consistency of Maximum Quasi-Likelihood Estimator in Quasi-Likelihood Nonlinear Models

在线全文

学校读者我要写书评

暂无评论

Journal of Mathematical Research and Exposition 2008年第1期28卷 192-198页

作者： xia tian, KONG Fan-chao Department of Statistics Yunnan University Yunnan 650091 China Department of Mathematics Anhui University Anhui 230039 China

This paper proposes some regularity conditions. On the basis of the proposed regularity conditions, we show the strong consistency of maximum quasi-likelihood estimation （MQLE） in quasi-likelihood nonlinear models ... 详细信息

关键词： maximum quasi-likelihood estimator quasi-likelihood nonlinear models strong consistency.