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共线型多路编码微音监测器
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作者 刘永华 《电子世界》 1998年第1期30-31,共2页
本文介绍的共线型多路编码微音监测器配合本刊1997年5~6期介绍的楼宇共线电话系统,可方便地实现商厦、仓库、银行、保密单位等夜间无人值守场所的声响监测,也可应用于军营、武警、监狱等特殊场所。该装置具有以下特点:(1)监测路数任意... 本文介绍的共线型多路编码微音监测器配合本刊1997年5~6期介绍的楼宇共线电话系统,可方便地实现商厦、仓库、银行、保密单位等夜间无人值守场所的声响监测,也可应用于军营、武警、监狱等特殊场所。该装置具有以下特点:(1)监测路数任意设置,所有监测器并联在一根普通双股绞织电线上,公用一组电源传送微音信号,安装方便,造价低廉。(2)四位数编码。 展开更多
关键词 共线型 多路编码监测器 微音监测器
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用途广泛的共线型音频通信电话机
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作者 刘永华 《无线电》 1997年第5期31-32,共2页
关键词 共线型 音频通信 电话机
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聚丙烯/线型低密度聚乙烯共混物流延膜的雾度与结构
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作者 管炳伟 《石油化工》 CAS CSCD 北大核心 2020年第6期569-575,共7页
向纯聚丙烯(PP)流延膜中引入了5%~15%(w)的线型低密度聚乙烯(LLDPE),利用白光干涉轮廓仪观察流延膜表面三维形貌,利用激光光散射研究了引入LLDPE后PP流延膜内部结构的变化,采用DSC研究了PP/LLDPE共混物在非等温结晶过程中的结晶行为。... 向纯聚丙烯(PP)流延膜中引入了5%~15%(w)的线型低密度聚乙烯(LLDPE),利用白光干涉轮廓仪观察流延膜表面三维形貌,利用激光光散射研究了引入LLDPE后PP流延膜内部结构的变化,采用DSC研究了PP/LLDPE共混物在非等温结晶过程中的结晶行为。实验结果表明,引入LLDPE可使PP流延膜的雾度从约2%降至1%以下,雾度下降的主要原因在于LLDPE的引入使PP流延膜表面的起伏变小;LLDPE的引入破坏了PP的球晶生长;PP/LLDPE共混物中PP和LLDPE组分的结晶温度分别比纯PP和纯LLDPE高,共混物中两组分存在相互作用。WAXD表征结果显示,向PP流延膜中引入LLDPE后,PP的晶型由以介晶为主转为以α晶为主,且PP晶体表现出显著的取向。 展开更多
关键词 聚丙烯/线型低密度聚乙烯混物 流延膜 雾度 结晶 取向
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浅析直接作用式隔水管张紧器结构及其工作原理
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作者 雒晓康 付坤伦 赵世刚 《智能建筑与工程机械》 2021年第4期64-66,共3页
本文以隔水管张紧器为研究对象,分析了直接作用式隔水管张紧器的功能优势,并对典型的直接作用式隔水管张紧器的结构和技术特点进行分析。结合海洋平台钻井技术、各种型式张紧器结构和作用优缺点推荐采用液缸共线型、活塞杆受压型的张紧... 本文以隔水管张紧器为研究对象,分析了直接作用式隔水管张紧器的功能优势,并对典型的直接作用式隔水管张紧器的结构和技术特点进行分析。结合海洋平台钻井技术、各种型式张紧器结构和作用优缺点推荐采用液缸共线型、活塞杆受压型的张紧器,通过研究进一步实现产品的平台适用性。 展开更多
关键词 直接作用式 隔水管张紧器 共线型 活塞杆受压型
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Energy decay for a class of nonlinear wave equations with a critical potential type of damping
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作者 王玉珍 石佩虎 《Journal of Southeast University(English Edition)》 EI CAS 2010年第4期651-654,共4页
The Cauchy problem for the nonlinear wave equation with a critical potential type of damping coefficient(1+│x│)-1 and a nonlinearity │u│p-1u is studied.The total energy decay estimates of the global solutions a... The Cauchy problem for the nonlinear wave equation with a critical potential type of damping coefficient(1+│x│)-1 and a nonlinearity │u│p-1u is studied.The total energy decay estimates of the global solutions are obtained by using multiplier techniques to establish identity ddtE(t)+F(t)=0 and skillfully selecting f(t),g(t),h(t)when the initial data have a compact support.Using the similar method,the Cauchy problem for the nonlinear wave equation with a critical potential type of damping coefficient(1+│x│+t)-1 and a nonlinearity │u│p-1u is studied,similar solutions are obtained when the initial data have a compact support. 展开更多
关键词 nonlinear wave equation energy decay critical potential type nonlinear damping self-conjugate operator
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Classification of breast lesions based on a dual S-shaped logistic model in dynamic contrast enhanced magnetic resonance imaging 被引量:8
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作者 DANG Yi GUO Li +2 位作者 LV DongJiao WANG XiaoYing ZHANG Jue 《Science China(Life Sciences)》 SCIE CAS 2011年第10期889-896,共8页
This study proposes a novel dual S-shaped logistic model for automatically quantifying the characteristic kinetic curves of breast lesions and for distinguishing malignant from benign breast tumors on dynamic contrast... This study proposes a novel dual S-shaped logistic model for automatically quantifying the characteristic kinetic curves of breast lesions and for distinguishing malignant from benign breast tumors on dynamic contrast enhanced (DCE) magnetic resonance (MR) images.D(,) is the diagnostic parameter derived from the logistic model.Significant differences were found in D(,) between the malignant benign groups.Fisher's Linear Discriminant analysis correctly classified more than 90% of the benign and malignant kinetic breast data using the derived diagnostic parameter (D(,)).Receiver operating characteristic curve analysis of the derived diagnostic parameter (D(,)) indicated high sensitivity and specificity to differentiate malignancy from benignancy.The dual S-shaped logistic model was effectively used to fit the kinetic curves of breast lesions in DCE-MR.Separation between benign and malignant breast lesions was achieved with sufficient accuracy by using the derived diagnostic parameter D(,) as the lesion's feature.The proposed method therefore has the potential for computer-aided diagnosis in breast tumors. 展开更多
关键词 logistic model breast cancer dynamic contrast enhanced magnetic resonance imaging
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Modeling of daily pan evaporation using partial least squares regression
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作者 ABUDU Shalamu CUI ChunLiang +2 位作者 J. Phillip KING Jimmy MORENO A. Salim BAWAZIR 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第1期163-174,共12页
This study presented the application of partial least squares regression (PLSR) in estimating daily pan evaporation by utilizing the unique feature of PLSR in eliminating collinearity issues in predictor variables. ... This study presented the application of partial least squares regression (PLSR) in estimating daily pan evaporation by utilizing the unique feature of PLSR in eliminating collinearity issues in predictor variables. The climate variables and daily pan evaporation data measured at two weather stations located near Elephant Butte Reservoir, New Mexico, USA and a weather station located in Shanshan County, Xinjiang, China were used in the study. The nonlinear relationship between climate variables and daily pan evaporation was successfully modeled using PLSR approach by solving collinearity that exists in the climate variables. The modeling results were compared to artificial neural networks (ANN) models with the same input variables. The resuits showed that the nonlinear equations developed using PLSR has similar performance with complex ANN approach for the study sites. The modeling process was straightforward and the equations were simpler and more explicit than the ANN black-box models. 展开更多
关键词 MODELING daily pan evaporation partial least squares regression artificial neural networks meteorological data
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