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Influencing factors and preventive measures of infectious complications after intestinal resection for Crohn’s disease
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作者 Shi-Rong Lv Xiao Huang +4 位作者 Li-Yun Zhou Jie Shi Chu-Chu Gong Ming-Ke Wang Ji-Shun Yang 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第10期3363-3370,共8页
The incidence of Crohn’s disease(CD)has increased in recent years,with most patients requiring intestinal resection.Complications after intestinal resection for CD can lead to poor prognosis and recurrence,among whic... The incidence of Crohn’s disease(CD)has increased in recent years,with most patients requiring intestinal resection.Complications after intestinal resection for CD can lead to poor prognosis and recurrence,among which infectious complic-ations are the most common.This study aimed to investigate the common risk factors,including medications,preoperative nutritional status,surgery-related factors,microorganisms,lesion location and type,and so forth,causing infectious complications after intestinal resection for CD,and to propose corresponding preventive measures.The findings provided guidance for identifying suscept-ibility factors and the early intervention and prevention of infectious complic-ations after intestinal resection for CD in clinical practice. 展开更多
关键词 Crohn’s disease Intestinal resection Postoperative infectious complications Influencing factors Preventive measures
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The diagnostic value of liver stiffness measurement combined with S index in the degree of hepatitis B liver fibrosis
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作者 XU Bin SUN Long 《Journal of Hainan Medical University》 CAS 2023年第10期24-28,共5页
Objective:To investigate the value of liver stiffness measurement(LSM)combined with S index in predicting the degree of liver fibrosis in hepatitis B patients.Methods:A total of 187 chronic hepatitis B patients who we... Objective:To investigate the value of liver stiffness measurement(LSM)combined with S index in predicting the degree of liver fibrosis in hepatitis B patients.Methods:A total of 187 chronic hepatitis B patients who were admitted to the Department of Infection,the First Affiliated Hospital of Hainan Medical College from January 2019 to December 2021 were selected.General data were collected,blood routine,liver function,liver fibrosis and liver stiffness measurement were tested,and S index,APRI and FIB-4 index were calculated,and liver biopsy was performed.Results:According to the pathological results of liver puncture,The patients were divided into no significant fibrosis group(n=86),significant fibrosis group(n=71)and cirrhosis group(n=30).There were significant differences in age,PLT,GGT,ALB,S index,HA,LN and LSM levels among the three groups(P<0.05).There was a good correlation between S index and the degree of hepatic fibrosis(rs=0.738,P<0.001).The AUC of S index and LSM for the diagnosis of significant fibrosis in hepatitis B were 0.873 and 0.792,respectively.And the AUC of S index and LSM for the diagnosis of liver cirrhosis were 0.966 and 0.879,respectively.The AUC for the combined diagnosis of significant fibrosis and cirrhosis were 0.908 and 0.988,respectively.The AUROC of combined detection in the diagnosis of cirrhosis was higher than that of LSM,APRI and FIB-4(P<0.05).Conclusion:LSM combined with S index has certain application value in the diagnosis of liver fibrosis/cirrhosis in hepatitis B patients. 展开更多
关键词 Liver fibrosis Tliver stiffness measurement s index
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在片S参数计量比对结果浅析
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作者 刘晨 高岭 +7 位作者 栾鹏 陈婷 黄英龙 李艳奎 金诚 邹喜跃 陆景 陈科元 《计量学报》 CSCD 北大核心 2024年第9期1401-1406,共6页
中国电子科技集团公司第十三研究所作为主导实验室开展了在片S参数计量比对工作,对参比实验室提交的在片S参数测量结果进行了汇总分析,并用E_n值对各参比实验室测量结果进行了评价。通过在片S参数计量比对,确保了量值传递的准确、可靠,... 中国电子科技集团公司第十三研究所作为主导实验室开展了在片S参数计量比对工作,对参比实验室提交的在片S参数测量结果进行了汇总分析,并用E_n值对各参比实验室测量结果进行了评价。通过在片S参数计量比对,确保了量值传递的准确、可靠,特别是对在片S参数测量不确定度的主要来源统一了认识。同时也为业内提供了在片S参数测量一致性的比较平台。 展开更多
关键词 无线电计量 在片s参数 计量比对 矢量网络分析仪
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CARLESON MEASURES,RIEMANN-STIELTJES OPERATORS AND MULTIPLIERS ON F(p,q,s)SPACES IN THE UNIT BALL OF C^n 被引量:3
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作者 彭茹 吴悠 邓方文 《Acta Mathematica Scientia》 SCIE CSCD 2016年第3期635-654,共20页
This paper is devoted to characterizing the Riemann-Stieltjes operators and pointwise multipliers on F(p, q, s) spaces in the unit ball of C^n which contain many classical function spaces, such as the Bloch space, B... This paper is devoted to characterizing the Riemann-Stieltjes operators and pointwise multipliers on F(p, q, s) spaces in the unit ball of C^n which contain many classical function spaces, such as the Bloch space, BMOA and Q8 spaces. The boundedness and compactness of these operators on F(p, q, s) spaces are characterized by means of an embedding theorem, i.e., F(p,q, s) spaces boundedly embedded into the tent-type spaces Tp,s^∞(μ) 展开更多
关键词 Carleson measures F(p q s spaces tent-type spaces Riemann-stieltjes operators MULTIPLIERs
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Tracking a maneuvering target in clutter with out-of-sequence measurements for airborne radar 被引量:3
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作者 Weihua Wu Jing Jiang Yang Wan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第4期746-753,共8页
There are many proposed optimal or suboptimal al- gorithms to update out-of-sequence measurement(s) (OoSM(s)) for linear-Gaussian systems, but few algorithms are dedicated to track a maneuvering target in clutte... There are many proposed optimal or suboptimal al- gorithms to update out-of-sequence measurement(s) (OoSM(s)) for linear-Gaussian systems, but few algorithms are dedicated to track a maneuvering target in clutter by using OoSMs. In order to address the nonlinear OoSMs obtained by the airborne radar located on a moving platform from a maneuvering target in clut- ter, an interacting multiple model probabilistic data association (IMMPDA) algorithm with the OoSM is developed. To be practical, the algorithm is based on the Earth-centered Earth-fixed (ECEF) coordinate system where it considers the effect of the platform's attitude and the curvature of the Earth. The proposed method is validated through the Monte Carlo test compared with the perfor- mance of the standard IMMPDA algorithm ignoring the OoSM, and the conclusions show that using the OoSM can improve the track- ing performance, and the shorter the lag step is, the greater degree the performance is improved, but when the lag step is large, the performance is not improved any more by using the OoSM, which can provide some references for engineering application. 展开更多
关键词 out-of-sequence measurement(s (OosM(s)) Earth-centered Earth-fixed (ECEF) interacting multiple model (IMM) probabilistic data association (PDA) attitude.
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Confirmatory factor analysis of VISA-P scale and measurement invariance across sexes in athletes with patellar tendinopathy 被引量:1
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作者 Sergio Hernandez-Sanchez Ferran Abat +4 位作者 María D.Hidalgo Antonio I.Cuesta-Vargas Victor Segarra Jose M.Sanchez-Ibanez Antonia Gomez-Conesa 《Journal of Sport and Health Science》 SCIE 2017年第3期365-371,共7页
Background:The Victorian Institute of Sport Assessment–Patella(VISA-P) scale is the most condition-specific patient-reported outcome measure used to assess symptom severity in athletes with patellar tendinopathy.Prev... Background:The Victorian Institute of Sport Assessment–Patella(VISA-P) scale is the most condition-specific patient-reported outcome measure used to assess symptom severity in athletes with patellar tendinopathy.Previous exploratory factor analyses have been conducted to evaluate the scale's dimensionality,with inconsistent results,and the factor structure of the scale remains unclear.The aims of the present study were to determine the factorial structure of the VISA-P scale using confirmatory factor analysis(CFA) and test measurement invariance across sexes.Methods:The study included a convenience sample of 249 Spanish athletes with patellar tendinopathy.CFA was performed to assess factorial validity.Hypothesized 1-and 2-factor models were tested.Measurement invariance across sexes was evaluated via multi-group CFA with several fit indices using EQS 6.1 software.Results:The internal consistency coefficient was 0.74.Several CFA models were examined and the 1-factor model in which errors for Items 7 and8 were correlated showed acceptable fit in terms of comparative fit index(CFI) and goodness-of-fit index(GFI) statistics(CFI = 0.93;GFI = 0.94;standardized root mean square residual = 0.06;root mean square error of approximation = 0.10;90% confidence interval:0.08–0.13).This model was invariant across sexes.Conclusion:The 1-factor model of the Spanish version of the VISA-P scale(VISA-P-Sp) in which errors for Items 7 and 8 were correlated demonstrated relative fit in CFA.Scores obtained via VISA-P-Sp can be compared between men and women without sexes bias.Further studies should examine the VISA-P scale and other single-score patient-reported outcome measures concurrently. 展开更多
关键词 Jumper's knee measurement invariance Patient-reported outcome measure structural validity
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基于TDLAS的H_(2)S气体材料表面吸附特性研究
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作者 金建新 刘威 +3 位作者 宋振明 朱志辉 田冰 彭志敏 《激光与红外》 CAS CSCD 北大核心 2024年第5期710-717,共8页
在H_(2)S气体浓度在线监测过程中,因其具有粘附性强的特点,容易发生管线吸附,从而导致测量结果存在偏差,尤其在痕量H_(2)S检测过程中表现最为明显,所以开展H_(2)S气体管线材料表面吸附特性研究尤为必要。本文基于可调谐二极管激光吸收... 在H_(2)S气体浓度在线监测过程中,因其具有粘附性强的特点,容易发生管线吸附,从而导致测量结果存在偏差,尤其在痕量H_(2)S检测过程中表现最为明显,所以开展H_(2)S气体管线材料表面吸附特性研究尤为必要。本文基于可调谐二极管激光吸收光谱技术(TDLAS),设计并搭建了一套H_(2)S浓度在线测定系统,并对该系统进行了测量性能检验,在此基础上进行了H_(2)S在不锈钢材料表面常温吸附特性探究。实验结果表明,所搭建H_(2)S浓度在线测定系统具有稳定性强、检测限低和灵敏度高的特点,利用此系统可以实现痕量H_(2)S浓度的在线连续测定。经过一系列探究试验,证明了H_(2)S在不锈钢材料表面存在明显且稳定的吸附作用,得出了H_(2)S在不锈钢材料表面的单位面积吸附量在10^(14)(个/cm^(2))量级。实验结果可以为痕量硫化氢在线精准测量提供一定参考。 展开更多
关键词 TDLAs H_(2)s 测量系统 材料表面 吸附特性
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Resilience based importance measure analysis for SoS 被引量:12
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作者 PAN Xing WANG Huixiong +1 位作者 YANG Yanjing ZHANG Guozhong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第5期920-930,共11页
In a system of systems(SoS),resilience is an important factor in maintaining the functionality,stability,and enhancing the operation effectiveness.From the perspective of resilience,this paper studies the importance o... In a system of systems(SoS),resilience is an important factor in maintaining the functionality,stability,and enhancing the operation effectiveness.From the perspective of resilience,this paper studies the importance of the SoS,and a resilience-based importance measure analysis is conducted to provide suggestions in the design and optimization of the structure of the SoS.In this paper,the components of the SoS are simplified as four kinds of network nodes:sensor,decision point,influencer,and target.In this networked SoS,the number of operation loops is used as the performance indicator,and an approximate algorithm,which is based on eigenvalue of the adjacency matrix,is proposed to calculate the number of operation loops.In order to understand the performance change of the SoS during the attack and defense process in the operations,an integral resilience model is proposed to depict the resilience of the SoS.From different perspectives of enhancing the resilience,different measures,parameters and the corresponding algorithms for the resilience importance of components are proposed.Finally,a case study on an SoS is conducted to verify the validity of the network modelling and the resiliencebased importance analysis method. 展开更多
关键词 system of systems (sos) REsILIENCE network modelling IMPORTANCE measure ANALYsIs operation LOOP
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S型皮托管对向和非对向测量方法准确度实验研究
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作者 张乐垚 张亮 +3 位作者 郭素娜 郭虎林 鲁贵祥 孔令彩 《计量学报》 CSCD 北大核心 2024年第6期864-872,共9页
S型皮托管的对向和非对向测量方法准确度在不同工况下有较大差异。通过风洞实流实验对风速、流速攻角和结构参数对S型皮托管对向和非对向测量方法准确度的影响进行了研究。结果表明:风速由5 m/s变化至30 m/s时,在不同流速攻角下S型皮托... S型皮托管的对向和非对向测量方法准确度在不同工况下有较大差异。通过风洞实流实验对风速、流速攻角和结构参数对S型皮托管对向和非对向测量方法准确度的影响进行了研究。结果表明:风速由5 m/s变化至30 m/s时,在不同流速攻角下S型皮托管对向和非对向测量准确度最大差异超过10%;对向和非对向测量中静压孔的压力变化是皮托管在较大流速攻角下造成测量误差的主因;外径较小、总静压孔距较大、测量端弯曲角度在15°至30°间、取压孔内径更小的S型皮托管在对向和非对向测量中都有更高的测量准确度;俯仰角取正值时对向测量准确度全面优于非对向测量,在俯仰角和偏航角同为45°时测量准确度差异达到最大值,大于70%。 展开更多
关键词 流量测量 s型皮托管 烟道流量 对向测量 非对向测量 测量准确度
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基于TDLAS的H_(2)S高温反应特性实验研究
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作者 王嘉琦 田思迪 +3 位作者 高东波 田志伟 彭志敏 杜艳君 《热力发电》 CAS CSCD 北大核心 2024年第2期162-169,共8页
电站锅炉在低NO_(x)燃烧过程中因锅炉内还原性气氛浓度较高,会产生较多H_(2)S气体。针对H_(2)S因具有易燃、强腐蚀性、剧毒性而可能对火电厂造成多种危害的问题,采用可调谐二极管激光吸收光谱(tunable diode laser absorption spectrosc... 电站锅炉在低NO_(x)燃烧过程中因锅炉内还原性气氛浓度较高,会产生较多H_(2)S气体。针对H_(2)S因具有易燃、强腐蚀性、剧毒性而可能对火电厂造成多种危害的问题,采用可调谐二极管激光吸收光谱(tunable diode laser absorption spectroscopy,TDLAS)方法结合多通池和计算机搭建低气体摩尔分数在线测量系统,实现了对混合气体中摩尔分数在10–6量级H_(2)S的精确在线测量,并利用该测量系统进行了H_(2)S高温反应实验,探究实验温度和混合气体中O_(2)摩尔分数对该反应的影响。实验结果展示了压力为80 kPa、O_(2)摩尔分数为0~5%的条件下,H_(2)S开始发生化学反应的温度随O_(2)摩尔分数变化的变化规律,整体而言,混合气体中O_(2)摩尔分数越高,H_(2)S开始发生化学反应的温度越低。实验结果可以为锅炉烟气中H_(2)S的生成、转化和危害控制提供一定数据基础。 展开更多
关键词 TDLAs H_(2)s 在线测量 高温反应 O_(2)摩尔分数
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Integrability near the Boundary of the Poisson Integral of Some Singular Measures 被引量:1
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作者 SU Xiaofang ZHANG Yiping 《Wuhan University Journal of Natural Sciences》 CAS 2007年第3期395-401,共7页
We consider the Poisson integral u = P*μ on the half-space R+^N+1 ( N 〉 1 ) (or on the unit ball of the complex plane) of some singular measureμ. If μ is an s-measure (0 〈 s 〈 N), then some sharp estima... We consider the Poisson integral u = P*μ on the half-space R+^N+1 ( N 〉 1 ) (or on the unit ball of the complex plane) of some singular measureμ. If μ is an s-measure (0 〈 s 〈 N), then some sharp estimates of the integration of the harmonic function u near the boundary are given. In particular, we show that fpr p〉1,∫R^Nu^p(x,y)dx- y^-τ (y〉0,τ =(N-s)(p-1) ) (Given for p〉1, RN f 〉 0 and g 〉 0, " f-g " will mean that there exist constants C1 and C2, such that C1f ≤ g ≤ CEf ). 展开更多
关键词 Poisson kemel Harmonic function s-measure
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不同中医证型Wilson病患者肝脏纤维化差异及其与弹性硬度值的关系
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作者 吴晓倩 唐露露 +2 位作者 王金萍 李冰 王艺星 《中西医结合肝病杂志》 CAS 2024年第6期495-499,共5页
目的:探讨不同中医证型Wilson病(WD)患者肝脏硬度值(LSM)及纤维化指标差异及两者的关系。方法:回顾性收集2021年2月至2023年4月住院确诊的110例WD患者的临床资料,中医证型采用指标聚类分析,绘制聚类图。采用简单对应分析中医证型与ADL... 目的:探讨不同中医证型Wilson病(WD)患者肝脏硬度值(LSM)及纤维化指标差异及两者的关系。方法:回顾性收集2021年2月至2023年4月住院确诊的110例WD患者的临床资料,中医证型采用指标聚类分析,绘制聚类图。采用简单对应分析中医证型与ADL分级的相关性。比较不同中医证型的一般临床资料、LSM及肝纤维化相关指标,从而探讨LSM与肝纤维化及中医证型分布的关系。结果:WD患者中医证型以湿热内蕴证(59例,53.64%)居多,痰瘀互结证(43例,39.09%)次之,肝肾阴虚证(5例,4.54%)、脾肾阳虚证(3例,2.73%)较少;痰瘀互结证偏向0~Ⅰ级,湿热内蕴证偏向Ⅱ级,肝肾阴虚证偏向Ⅲ~Ⅳ级,脾肾阳虚证在二维投影图中间,并未偏向WD病变程度某一分级;痰瘀互结证、肝肾阴虚证、脾肾阳虚证患者肝脏LSM均高于湿热内蕴证(P<0.05);肝肾阴虚证、脾肾阳虚证患者血清透明质酸(HA)和Ⅳ型胶原(Ⅳ-C)水平高于湿热内蕴证、痰瘀互结证组(P<0.05),4组患者Ⅲ型前胶原氨基端肽(PⅢNP)、层黏连蛋白(LN)水平差异无统计学意义(P>0.05)。湿热内蕴证、痰瘀互结证、肝肾阴虚证中LSM与HA、Ⅳ-C均呈不同程度的正相关。结论:LSM联合血清学指标能更好地评估不同证型WD患者肝纤维化程度。 展开更多
关键词 WILsON病 中医证型 肝脏硬度值 肝纤维化
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基于激光吸收光谱的CO/CO_(2)/H_(2)S浓度同步在线测量研究
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作者 张学军 陈勤根 +3 位作者 杨展 邓琴 贺拴玲 彭志敏 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第5期1412-1416,共5页
CO、CO_(2)、H_(2)S是燃煤锅炉炉内气氛重要组成部分,其浓度不仅能够反映燃烧工况,还可作为水冷壁高温腐蚀程度判断依据,因此实现CO、CO_(2)、H_(2)S浓度的准确测量意义重大。首先采用波长调制-直接吸收(WM-DAS)方法结合约40 m长光程Her... CO、CO_(2)、H_(2)S是燃煤锅炉炉内气氛重要组成部分,其浓度不仅能够反映燃烧工况,还可作为水冷壁高温腐蚀程度判断依据,因此实现CO、CO_(2)、H_(2)S浓度的准确测量意义重大。首先采用波长调制-直接吸收(WM-DAS)方法结合约40 m长光程Herriott池,在室温低压下,开展不同CO/CO_(2)浓度配比下三种气体吸收率同步测量实验,结果表明三种气体的吸收率测量值与理论计算值相近,相对误差在6.82%以内,测量结果可靠性较高;然后对不同浓度CO/CO_(2)(0~2000μL·L^(-1))、H_(2)S(0~20μL·L^(-1))进行动态测量,结果表明,测量系统对三种组分浓度变化的响应具有较好的线性度。 展开更多
关键词 波长调制-直接吸收光谱 CO浓度 CO_(2)浓度 H_(2)s浓度 同步测量
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Supplier Evaluation Model Based on Fuzzy Measures and Choquet Integral
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作者 武建章 张强 桑圣举 《Journal of Beijing Institute of Technology》 EI CAS 2010年第1期109-114,共6页
To identify interactions among evaluation criteria and describe their importance,a new identification method making use of a fuzzy measure is presented.The relative weight and interaction degree of every evaluation cr... To identify interactions among evaluation criteria and describe their importance,a new identification method making use of a fuzzy measure is presented.The relative weight and interaction degree of every evaluation criteria pair are obtained by using the diamond pairwise comparison method.Based on comparison results,the maximum eigenvector method of analytic hierarchy process (AHP),the hierarchical clustering method,and the phi(s) transformation are utilized to generate values of the fuzzy measure for each subset of the evaluation criterion set.Overall evaluation on each supplier is aggregated by Choquet integral with respect to the fuzzy measure.Finally,an illustrative example demonstrates the practical feasibility and validity of the proposed method. 展开更多
关键词 fuzzy measure Choquet integral diamond pairwise comparison phi(s transformation supplier evaluation
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Simultaneous measurements of aeroacoustic sounds and wall vibration for exploring the contribution of tooth vibration in the production of sibilant sounds/s/
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作者 Masanori Nakamura Kazunori Nozaki +3 位作者 Haruka Takimoto Kazuya Nagamune Motoharu Fujigaki Shigeo Wada 《Journal of Biomedical Science and Engineering》 2011年第2期83-89,共7页
In order to understand the contribution of teeth vibration to the production of sibilant/s/, the pre-sent study was designed to develop a method of simultaneously measuring aeroacoustic sounds and the vibration of an ... In order to understand the contribution of teeth vibration to the production of sibilant/s/, the pre-sent study was designed to develop a method of simultaneously measuring aeroacoustic sounds and the vibration of an obstacle. To measure the vibration without disturbing flow, the Michelson interferometer was employed. The flow channel, which had an obstacle wall inside of it, was fabricated such that it morphologically mimicked the simplified geometry of the oral cavity. Given airflows at a flow rate of 7.5 × 10–4 m3/s from the inlet, aeroacoustic sounds were generated. A spectrum analy-sis of the data demonstrated two prominent peaks in the sound at 1,300 and 3,500 Hz and one peak in the wall vibration at 3,500 Hz. The correlation in peak frequencies between the sound and wall vibration suggests that the sound at 3,500 Hz was induced by the wall vibration. In fact, the sound amplitude at 3,500 Hz decreased when the obstacle wall was thickened, which increased its rigidity (p < 0.05, t-test). The experimental results demonstrate that the developed techniques are capable of measuring aeroacoustic sound and obstacle wall vibration simultaneously, and suggest the potential to pave the way for detailed analysis of the production of sibilant sounds /s/. 展开更多
关键词 Acoustic measureMENT VIBRATION measureMENT Michelson INTERFEROMETER Aeroacoustics sibilant/s/
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Nikodým-Type Theorems for Lattice Group-Valued Measures with Respect to Filter Convergence
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作者 Antonio Boccuto Xenofon Dimitriou 《Advances in Pure Mathematics》 2014年第5期213-221,共9页
We present some convergence and boundedness theorems with respect to filter convergence for lattice group-valued measures. We give a direct proof, based on the sliding hump argument. Furthermore we pose some open prob... We present some convergence and boundedness theorems with respect to filter convergence for lattice group-valued measures. We give a direct proof, based on the sliding hump argument. Furthermore we pose some open problems. 展开更多
关键词 LATTICE Group (Free) FILTER (s)-Bounded measure σ-Additive measure Diagonal FILTER Block-Respecting FILTER Limit THEOREM Nikodym Boundedness THEOREM
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The matrix representation for the mathematic structure of Shannon’s information measures
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作者 苑延华 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2007年第2期232-235,共4页
Shannon’s information measure is a crucial concept in Information Theory. And the research, for the mathematics structure of Shannon’s information measure, is to recognize the essence of information measure. The lin... Shannon’s information measure is a crucial concept in Information Theory. And the research, for the mathematics structure of Shannon’s information measure, is to recognize the essence of information measure. The linear relation between Shannon’s information measures and some signed measure space by using the formal symbols substitution rule is discussed. Furthermore, the coefficient matrix recurrent formula of the linear relation is obtained. Then the coefficient matrix is proved to be invertible via mathematical induction. This shows that the linear relation is one-to-one, and according to this, it can be concluded that a compact space can be generated from Shannon’s information measures. 展开更多
关键词 ENTROPY shannon's information measures signed measure the recurrent formula of l-measure matrix
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Data from Twenty-Three FRB’s Confirm the Universe Is Static and Not Expanding
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作者 Lyndon Errol Ashmore 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第3期1152-1177,共26页
Fast Radio Bursts from far away galaxies have travelled through the IGM and provide a tool to study its composition. Presently there are 23 FRB’s whose host galaxies have been identified and the redshift found. This ... Fast Radio Bursts from far away galaxies have travelled through the IGM and provide a tool to study its composition. Presently there are 23 FRB’s whose host galaxies have been identified and the redshift found. This gives us the opportunity to test Dispersion Measure versus redshift predictions made by two models. The Macquart relation for an expanding Universe and the New Tired Light relationship in a static universe. In New Tired Light, redshifts are produced when a photon is absorbed and re-emitted by the electrons in the IGM which recoil on both occasions. Some of the energy of the photon has been transferred to the kinetic energy of the recoiling electron. The photon has less energy, a lower frequency and a longer wavelength. It has been redshifted. Since dispersion is due to an interaction between radio signals and these same electrons one would expect a direct relationship between DM and redshift in the New Tired light model. The relation is DM=(mec/2hre)ln(1+z)and contains no adjustable parameters—just a combination of universal constants related to the electron and photon. Notice that the relation is independent of the electron number density ne since a change in ne affects both the DM and redshift equally. A graph of DM versus ln(1 + z) will be a straight line of gradient (mec/2hre)and, using SI units, substituting for the constants gives 7.318 × 1025 m−2. Using the data from the 23 well localized FRB’s, with the weighting of the DM’s for expansion removed (so that the data corresponds to a static universe), a graph of DM versus ln(1 + z) has a gradient of 6.7 × 1025 m−2—9% below the predicted (mec/2hre). The Macquart relation involves highly processed data and adjustable parameters to allow for “dark energy” and “dark matter” (neither of which has yet been found) and can be reduced to DM = 850z (in units of pc∙cm−3). Using the data from this set of localized FRB’s gives a trendline with gradient 1.10 × 103 pc∙cm−3—almost 30% higher than that predicted in an expanding universe model. The FRB data clearly comes down in favour of a static universe rather than an expanding one. Combining the DM-z relationship for the 23 well localized FRB’s, with the Hubble diagram, drawn using the NED-D compilation of redshift independent extragalactic distances, produces a value of “ne” the mean electron number density of the IGM, of ne=0.48 m−3close to the value ne=0.5 m−3, long since predicted by NTL. 展开更多
关键词 REDsHIFT Dispersion measure Fast Radio Bursts FRB’s Tired Light static Universe IGM
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Precision Frequency Measurement of ^(87)Rb 5S_(1/2)(F=2)→5D_(5/2)(F″=4)Two-Photon Transition through a Fiber-Based Optical Frequency Comb
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作者 夏巍 戴少阳 +3 位作者 张胤 李坤乾 于齐 陈徐宗 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第5期30-34,共5页
The absolute frequency of 87Rb 5S1/2 (F=2)→5D5/2 (F" = 4) two-photon transition at 778nm is measured in an accuracy of 44kHz. A home-made erbium-doped fiber laser frequency comb with frequency stability of 5.0 ... The absolute frequency of 87Rb 5S1/2 (F=2)→5D5/2 (F" = 4) two-photon transition at 778nm is measured in an accuracy of 44kHz. A home-made erbium-doped fiber laser frequency comb with frequency stability of 5.0 × 10-13@1 s is employed for the light source. By using a periodically poled lithium niobate, the femtosecond pulse operating in 1556 nm is frequency-doubled to 778 nm to obtain the direct two-photon transition spectroscopy of thermal rubidium vapor. Through sweeping the carrier envelope offset frequency (fceo), the 5S1/2 (F=2)→5D5/2 (F" = 4) two-photon transition line is clearly resolved and its absolute frequency is determined via the peak-finding of the fitting curve. After the frequency correction, the measured result agrees well with the previous experiment on this transition. The entire potential candidate of optical frequency standard for system configuration is compact and robust, providing a telecommunication applications. 展开更多
关键词 Precision Frequency measurement of in is F=2 on as been Rb 5s F Two-Photon Transition through a Fiber-Based Optical Frequency Comb
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Novel similarity measures for face representation based on local binary pattern
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作者 祝世虎 封举富 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第2期223-226,共4页
The successful face recognition based on local binary pattern(LBP)relies on the effective extraction of LBP features and the inferring of similarity between the extracted features.In this paper,we focus on the latter ... The successful face recognition based on local binary pattern(LBP)relies on the effective extraction of LBP features and the inferring of similarity between the extracted features.In this paper,we focus on the latter and propose two novel similarity measures for the local matching methods and the holistic matching methods respectively.One is Earth Mover's Distance with Hamming and Lp ground distance(EMD-HammingLp),which is a cross-bin dissimilarity measure for LBP histograms.The other is IMage Hamming Distance(IMHD),which is a dissimilarity measure for the whole LBP images.Experiments on FERET database show that the proposed two similarity measures outperform the state-of-the-art Chi-square similarity measure for extraction of LBP features. 展开更多
关键词 similarity measurement local binary pattern Earth Mover's Distance IMage Euclidean Distance
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