Structural modal parameter identifi cation and damage diagnosis based on Hilbert-Huang transform

Traditional modal parameter identifi cation methods have many disadvantages,especially when used for processing nonlinear and non-stationary signals.In addition,they are usually not able to accurately identify the damping ratio and damage.In this study,methods based on the Hilbert-Huang transform(HHT) are investigated for structural modal parameter identifi cation and damage diagnosis.First,mirror extension and prediction via a radial basis function(RBF) neural network are used to restrain the troublesome end-effect issue in empirical mode decomposition(EMD),which is a crucial part of HHT.Then,the approaches based on HHT combined with other techniques,such as the random decrement technique(RDT),natural excitation technique(NExT) and stochastic subspace identifi cation(SSI),are proposed to identify modal parameters of structures.Furthermore,a damage diagnosis method based on the HHT is also proposed.Time-varying instantaneous frequency and instantaneous energy are used to identify the damage evolution of the structure.The relative amplitude of the Hilbert marginal spectrum is used to identify the damage location of the structure.Finally,acceleration records at gauge points from shaking table testing of a 12-story reinforced concrete frame model are taken to validate the proposed approaches.The results show that the proposed approaches based on HHT for modal parameter identifi cation and damage diagnosis are reliable and practical.

Point-of-care ultrasound identifi cation of yolk stalk sign in a case of failed fi rst trimester pregnancy

Emergency physicians are often the first providersto encounter patients with complications in earlypregnancy. Point-of-care （POC） pelvic ultrasound isbeing increasingly used in the evaluation of emergencydepartment （ED） patients with first trimester symptoms.[1]While the initial aim of POC ultrasound in this settingis to confirm an intrauterine pregnancy, a secondarygoal is to differentiate between a normal and abnormalpregnancy. There exist a number of sonographic featuresto suggest a pregnancy is non-viable.

高校研究生心理问题识别的标准化过程--基于辅导员工作案例的分析

我国高校研究生群体面临着来自学业、就业、家庭等多方面的压力,心理健康状况不容乐观。研究生的心理健康状况事关我国高水平人才的培养质量,事关教育强国建设。本文通过呈现一个真实的辅导员工作案例,从工作目标、工作内容、基本途径方法三个方面,探讨了辅导员、班主任等高校教师队伍对于研究生心理危机问题进行有效识别的标准化过程,从而为准确界定学生危机问题、开展危机干预奠定良好基础。

The Theory and Practice of the Interpretation Identification System Designing of Geoparks

In this paper,the author defined the interpretation system of geoparks,studied the designing princeples and methods of the interpretation identification system,including the information,content and appearance. Furthermore,the designing of the interpretation identification system designing of the Hanas National Geopark was conducted as an empirical study,

Application of multi-component joint inversion in oil and gas exploration:A case study of reservoir and gas saturation prediction of the Xujiahe formation in the PLN area of the central Sichuan Basin

Multi-component seismic exploration is an important technique in the utilization of P-waves and converted S-waves for oil and gas exploration.It has unique advantages in the structural imaging of gas zones,reservoir prediction,lithology,and gas-water identifi cation,and the development direction and degree of fractures.Multi-component joint inversion is one of the most important steps in multi-component exploration.In this paper,starting from the basic principle of multi-component joint inversion,the diff erences between the method and single P-wave inversion are introduced.Next,the technique is applied to the PLN area of the Sichuan Basin,and the P-wave impedance,S-wave impedance,and density are obtained based on multi-component joint inversion.Through the velocity and lithology,porosity,and gas saturation fi tting formulas,prediction results are calculated,and the results are analyzed.Finally,multi-component joint inversion and single P-wave inversion are compared in eff ective reservoir prediction.The results show that multi-component joint inversion increases the constraints on the inversion conditions,reduces the multi-solution of a single P-wave inversion,and is more objective and reliable for the identification of reservoirs,effectively improving the accuracy of oil and gas reservoir prediction and development.

Geometrical Frameworks in Identification Problem

The purpose of this review is to apply geometric frameworks in identification problems. In contrast to the qualitative theory of dynamical systems (DSQT), the chaos and catastrophes, researches on the application of geometric frameworks have not been performed in identification problems. The direct transfer of DSQT ideas is inefficient through the peculiarities of identification systems. In this paper, the attempt is made based on the latest researches in this field. A methodology for the synthesis of geometric frameworks (GF) is proposed, which reflects features of nonlinear systems. Methods based on GF analysis are developed for the decision-making on properties and structure of nonlinear systems. The problem solution of structural identifiability is obtained for nonlinear systems under uncertainty.

SYNTHESIS AND CATIONIC RING-OPENING POLYMERIZATION OF 1, 4-ANHYDRO-2, 3-DI-O-(P-AZIDOBENZYL)-α-D-RIBOPYRANOSE

New highly stereoregular 2, 3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1, 4-anhydro-2, 3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using phosphorus pentafluoride or tin tetrachloride as catalyst at low temperature indichloromethane. The monomer was obtained by the reaction of p - bromomethyl -phenyleneazide with 1, 4 -anhydro-α-D-ribose in DMF. The structure of poly(ADANR) was identified by specific rotation and ^(13)C-NMR spectroscopy. Acid chloride-AgCl_4 complex catalyst such as CH_2=C(CH_3)C^+OClO_4^- used in thepolymerization resulted in polymers with mixed structures, i.e. (1→5)-α-D-ribofuranosidic and (1→4)-β-D-ribopyranosidic units. However, with C_6H_5C^+OClO_4^- as catalyst, pure (1→5)-α-D-ribofuranan was obtained.The effects of catalyst, polymerization temperature and time on polymer stereoregularity were examined, andthe mechanism of the ring-opening polymerization was discussed.

Stereoselective cycloaddition of N-acyliminium cations withα,β-unsaturated ketones and esters

The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoindol-1-ones in the presence of BFa.OEt2 could be reacted with α,β-unsaturated ketones and esters to afford stereoselectively the cycloaddition products 6-acylisoindolo[2,1- a]quinolin-11-ones in moderate to high yields. C 2009 Wei Zhang. Published by Elsevier B.V, on behalf of Chinese Chemical Society. All rights reserved.

对甘精胰岛素有关物质分析用系统适用性试验的研究

目的:对不同企业甘精胰岛素有关物质分析用系统适用性试验进行研究,发现存在的问题,提示企业完善质量标准,更科学有效地控制产品质量。方法:采用高效液相色谱法及液质联用方法对不同企业有关物质分析用系统适用性试验进行研究评价,发现存在多种问题。结果:部分企业系统适用性溶液中所用的“0A-甘精胰岛素”的结构经LC-MS/MS确认后,发现与理论序列不同,部分企业采用酶切方法制备系统适用性溶液,存在杂质较多、操作步骤复杂、溶液易浑浊等问题。结论:建议企业提高对系统适用性试验的重视程度,加强研究,完善质量标准,科学有效地进行药品质量控制。

鹿茸标准鉴别技术进展研究

鹿茸是一种具有重要药用价值的中药材,具有多种功效和广泛的临床应用。然而,由于市场上出现了大量的假冒伪劣产品,对鹿茸的鉴别技术的研究变得十分重要。本文综述了近年来鹿茸的鉴别技术进展,包括传统的鉴别方法以及现代分子生物学和化学分析技术等。同时,还对当前鹿茸鉴别技术的挑战和未来发展方向进行了讨论。

基于HMM与SVM的运动跌倒预警模型研究——以安徽省老年群体为例

人口老龄化问题日益加重,老年人的身体机能随着年龄的增加而降低.为提升运动跌倒预警的检测率和延长预留时间,提出基于HMM与SVM的运动跌倒预警模型,通过人体行为特征分析和判别算法设计实现运动跌倒的成功预测,并以安徽省老年群体为背景,从中采集实验数据.实验结果表明,SVM模型的检测率为69.5%,基于HMM与SVM的运动跌倒预警模型的检测率为91%,对比结果表明基于HMM与SVM的运动跌倒预警模型针对突发情况的误判率较低,具备良好的泛化能力.基于HMM与SVM的运动跌倒预警模型检测的平均预留时间是245 ms,满足充气机构反应耗时,结果有助于老年人跌倒预警以及人体保护.

社区获得性耐甲氧西林金黄色葡萄球菌(CA-MRSA)感染特点及治疗对策的研究进展

CA-MRSA指从门诊患者或是从住院48 h内的患者中分离出来的MRSA菌株,CA-MRSA与HA-MRSA感染的危险因素、患者群和感染特点均有较大的区别。本文综述了有关CA-MRSA引起感染性疾病的流行病学、基因分型鉴定方法、感染特点、对抗菌药物耐药性及治疗对策等研究进展。

相似异源指纹研究进展及展望

指纹鉴定错案的发生引发了对指纹证据科学性要求的提高,伴随着指纹数据库的不断扩增,指纹相似异源问题已经成为指纹检验领域的重要研究内容之一,其对指纹鉴定标准的构建具有重要意义,也给指纹鉴定带来风险和挑战。本文首先介绍相似异源指纹的研究背景以及概念,然后从相似异源指纹的产生原因和鉴定错误率两方面展开综述,最后结合研究现状对其未来的发展趋势提出几点展望,以期补充指纹鉴定基础理论,为指纹证据的量化评价提供一定的参考。

GC-MS-AMDIS结合保留指数分析比较青椒与竹叶花椒挥发油的组成成分

目的:研究比较青椒与竹叶花椒挥发油组成成分及相对含量。方法:采用水蒸气蒸馏法提取挥发油,以气相色谱-质谱联用法(GC-MS)和自动质谱退卷积定性系统(AMDIS)结合Kováts保留指数(Retention index.RI)分析两者的化学成分。结果:样品中共鉴定66个化合物,青椒药材挥发油样品共鉴定出45种化合物,其中主要成分为爱草脑、芳樟醇、柠檬烯、大根香叶烯D和石竹烯等,且样品中挥发油相对含量最高的成分为爱草脑。竹叶花椒药材挥发油样品共鉴定出49个化合物,其中主要含有芳樟醇、柠檬烯、(-)-4-萜品醇、乙酸芳樟酯、α-松油醇和大根香叶烯D等。且样品中挥发油相对含量最高的成分为芳樟醇。结论:青椒和竹叶花椒挥发油的组成存在显著性差异。

基于改进FCM的超超临界机组过热器T-S神经网络模型辨识

构建了过热器多输入单输出的T-S神经网络模型,并针对输入变量空间划分问题提出了一种改进FCM算法。通过确定高斯型隶属函数参数,实现模型结构参数辨识,利用递推最小二乘法完成模型后件参数辨识。对华能海门电厂百万机组过热器模型辨识进行仿真,结果表明此方法具有较好的辨识效果,辨识出的过热器模型具有较好的精度和泛化能力。

从结构相似模型化合物进行天然产物结构鉴定-以番石榴叶黄酮苷类化合物鉴定为例

天然产物的结构鉴定主流手段是核磁共振波谱法,与结构相似模型化合物的核磁数据进行比较,确定未知化合物结构是一种重要的方式。论文从结构鉴定过程中有机分子可分拆解析,如何寻找相似模型化合物和实例例举3个方面,探讨相似模型化合物对于未知图谱结构鉴定的作用和意义,并建议在平时的结构分析过程中注重模型化合物数据的收集和积累。

职业本科学校校企合作育人项目风险识别与对策研究

为系统性识别职业本科学校校企合作育人项目中存在的风险因素及其影响机理并提出应对策略,提升职业本科学校就业质量和企业绩效,促进职业本科学校与企业合作育人项目的推进。本研究基于产教融合背景,以职业本科学校为研究主体,采用DEMATEL-ISM方法,对风险因素间相互影响关系以及对项目总体影响强度进行了分析,计算了风险因素的中心度和原因度,构建了多层次解释结构模型,划分了风险因素的影响层次,明确了各层次间的风险传递路径,可为有效管控校企育人项目风险提供决策参考。

笔迹鉴定的量化及统计学应用方法综述

统计学方法在笔迹鉴定领域的研究中越来越受到重视,采取有效的统计学方法对笔迹的特征进行客观量化,并对特征数据进行合理的分析,不仅可以为笔迹鉴定结论提供强有力的理论依据,更可以深入挖掘复杂数据背后的信息。本文梳理了笔迹特征量化和特征数据处理中几种常用统计学方法,介绍了它们的原理、应用以及最新进展,并对笔迹鉴定中统计学方法进行了展望。

儿童病理性骨折伤残鉴定1例

儿童病理性骨折发病隐匿,病变部位骨质薄弱,常在遭受外力后确诊为病理性骨折,通常情况下骨折线位于肿瘤部位。儿童病理性骨折伤残等级鉴定较为少见,这类案件在法医临床鉴定活动中争议较大,损伤与疾病共存情况下,如何评定伤残等级及伤病关系处理是该类案件的难点。笔者结合一个儿童病理性骨折案例,分别从病历资料完整性、影像学资料选择、DICOM文件使用、鉴定时机选择、伤病关系处理五个方面总结鉴定过程中需注意的要点,为之后相似的鉴定活动提供参考。

一种基于深度报文检测的合成视频质量评估方法

移动视频业务快速发展,用户感知与网络KPI指标发生偏离,传统视频运维支撑手段存在端到端问题定界难的问题。本文对国内电信运营商移动视频业务特性进行分析,提出一种基于深度报文检测的视频合成算法,将事务级的DPI单据进行关联,以一个完整的视频业务为单位输出相关体验评估信息,进而研究以业务级为基础的DPI指标,用于评估用户观看完整视频的全过程感知,提升用户感知保障。此方法能够覆盖主流的视频网站资源,本文所提出的方法经过实际应用验证,可真实评估视频质量及用户感知体验,助力实现国内电信运营商通信网络问题定界与网络自动驾驶。