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文章速递Emulation of Realistic Multi-Path Propagation Channels inside an Anechoic Chamber for Antenna Diversity Measurements 认领
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作者 Alaa Choumane Ahmad El Sayed Ahmad Khaled Khoder 《无线工程与技术(英文)》 2020年第1期1-12,共12页
As antennas are inherently included recommended in Over-The-Air (OTA) testing, it is important to also consider realistic channel models for the multiple-input multiple-output (MIMO) device performance evaluation. Thi... As antennas are inherently included recommended in Over-The-Air (OTA) testing, it is important to also consider realistic channel models for the multiple-input multiple-output (MIMO) device performance evaluation. This paper aims to emulate realistic multi-Path propagation channels in terms of angles of arrivals (AoA) and cross-polarization ratio (XPR) with Rayleigh fading, inside an anechoic chamber, for antenna diversity measurements. In this purpose, a practical multi-probe anechoic chamber measurement system (MPAC) with 24 probe antennas (SATIMO SG24) has been used. However, the actual configuration of this system is not able to reproduce realistic channels. Therefore, a new method based on the control of the SG24 probes has been developed. At first time, this method has been validated numerically through the comparison of simulated and analytical AoA probability density distributions. At the second time, the performance of an antenna diversity system inside the SG24 has been performed in terms of the correlation coefficient and diversity gain (DG) using an antenna reference system. Simulated and measurements results have shown a good agreement. 展开更多
关键词 Channel Emulation Multi-Path OTA Measurements Antenna Diversity Measurements MIMO Correlation Coefficient Diversity Gain
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多泵浦的碲基喇曼光纤放大器增益研究 认领
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作者 巩稼民 王杰 +5 位作者 张晨 马豆豆 刘爱萍 杨红蕊 郝倩文 张丽红 《光通信技术》 北大核心 2020年第6期41-45,共5页
针对密集波分复用光纤通信系统中喇曼光纤放大器的增益平坦度较低、带宽较窄的问题,从前向多泵浦喇曼放大器耦合方程入手,采用龙格-库塔法,使用碲基光纤作为多泵浦喇曼放大器的增益光纤,通过Matlab分析了多波长泵浦中泵浦数量、泵浦功... 针对密集波分复用光纤通信系统中喇曼光纤放大器的增益平坦度较低、带宽较窄的问题,从前向多泵浦喇曼放大器耦合方程入手,采用龙格-库塔法,使用碲基光纤作为多泵浦喇曼放大器的增益光纤,通过Matlab分析了多波长泵浦中泵浦数量、泵浦功率和光纤长度对增益及增益平坦度的影响,最终通过采用6个泵浦,并合理设置泵浦功率,实现了100 nm传输带宽的仿真。 展开更多
关键词 喇曼光纤放大器 碲基光纤 多泵浦 增益 增益平坦度
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基于粒子群优化算法的双向多泵浦光纤拉曼放大器增益研究 认领
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作者 巩稼民 王杰 +5 位作者 张晨 马豆豆 刘爱萍 杨红蕊 郝倩文 张丽红 《激光与红外》 CAS CSCD 北大核心 2020年第9期1069-1074,共6页
基于石英光纤作为增益介质,采用龙格-库塔法、打靶法求解多波长双向泵浦光纤拉曼放大器的功率耦合波方程,得到拉曼放大器的增益带宽,平均增益,增益平坦度以及泵浦光和信号光沿光纤的分布。再通过粒子群优化算法对同一数量泵浦光不同排... 基于石英光纤作为增益介质,采用龙格-库塔法、打靶法求解多波长双向泵浦光纤拉曼放大器的功率耦合波方程,得到拉曼放大器的增益带宽,平均增益,增益平坦度以及泵浦光和信号光沿光纤的分布。再通过粒子群优化算法对同一数量泵浦光不同排列双向系统进行逐个优化分析,在14种双向泵浦结构中选出性能较优的三种结构,再对它们优化参数设置,最终得到性能最优的双向泵浦结构BBFF。研究结果表明:在仅有四个泵浦光的情况下,双向多泵浦结构BBFF具有最优的平均增益和增益平坦度,并且得到了开关增益为23.1665 dB,增益平坦度为0.794 dB的双向泵浦结构。 展开更多
关键词 拉曼光纤放大器 双向 多泵浦 增益 增益平坦度
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Genetic Improvement of Barley (<i>Hordeum vulgare</i>, L.) in Brazil: Yield Increase and Associated Traits 认领
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作者 Osmar Rodrigues Euclydes Minella Edson Roberto Costenaro 《农业科学(英文)》 2020年第4期425-438,共14页
Barley breeding program in Brazil has focused on characteristics associated with malting for beer purposes as the main economic application for this crop. The breeding process focused on selection for grain yield, dis... Barley breeding program in Brazil has focused on characteristics associated with malting for beer purposes as the main economic application for this crop. The breeding process focused on selection for grain yield, disease resistance and malting quality. The objective of this work was to quantify the genetic gain in barley grain yield from 1968 and 2008 in Brazil and to identify the physiological characteristics associated with the increase of grain yield. Field experiments with five 2-row barley cultivars were tested from 2011 to 2013 in the absence of biotic and abiotic stresses and with mechanical restriction to lodging. The ANOVA showed no genetic gain until 1980 with average grain yield of 4.632 kg/ha. After 1980, there was a productivity increase of 59.9 kg/ha/year. No correlation was observed between total maturity biomass and the year of release of the cultivars, while harvest index and plant height, were significantly improved. The main component associated with grain yield was the number of grains/m2, due to the higher number of spikes/m2 associated to a greater contribution of the tillers in the modern cultivars. 展开更多
关键词 BARLEY Grain YIELD Developmental Phases Genetic Gain YIELD Components
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Comparative Analysis on Antenna Balun and Feeding Techniques of Step Constant Tapered Slot Antenna 认领
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作者 Mousumi Aktar Md. Masud Rana +1 位作者 Nayan Sarker Md. Sanwar Hossain 《传感技术(英文)》 2020年第3期31-45,共15页
This paper represents the performance analysis of the different shapes of antenna balun and feeding techniques for step constant tapered slot antenna. This work also addresses the benefits of antenna balun (circular a... This paper represents the performance analysis of the different shapes of antenna balun and feeding techniques for step constant tapered slot antenna. This work also addresses the benefits of antenna balun (circular and rectangular) along with two types of feeding techniques (Microstrip line L-shape and Microstrip line I-shape). The performance of the antenna for each technique is thoroughly investigated using Computer Simulation Technology (CST) Microwave Studio software simulation under the resonant frequency of 5.9 GHz. Results demonstrate that the proposed model is an effective tool for improving antenna performance. Moreover, an extensive comparison has been carried out between the two different shapes, with and without antenna balun and between two feeding techniques focusing on return losses, gain, directivity, and voltage standing wave ratio (VSWR). 展开更多
关键词 Antenna Balun L-Shape Microstrip Feeding I-Shape Microstrip Feeding Return Loss Gain Radiation Pattern DIRECTIVITY CST Microwave Studio
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文章速递L波段喇曼光纤放大器的增益平坦化研究 认领
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作者 刘阳 周雪芳 《光通信技术》 CSCD 北大核心 2020年第11期39-42,共4页
由于单个泵浦源的喇曼光纤放大器(RFA)输出增益不平坦且增益较低,导致光纤通信系统的性能变差,设计了一个正向三泵结构的RFA。围绕合适的泵浦个数、泵浦波长和泵浦功率对RFA输出增益的影响,并结合OptiSystem软件对L波段RFA的增益进行优... 由于单个泵浦源的喇曼光纤放大器(RFA)输出增益不平坦且增益较低,导致光纤通信系统的性能变差,设计了一个正向三泵结构的RFA。围绕合适的泵浦个数、泵浦波长和泵浦功率对RFA输出增益的影响,并结合OptiSystem软件对L波段RFA的增益进行优化设计与仿真分析。仿真结果表明:所设计的RFA实现了在L波段大于10 dB的增益且较为平坦,最大增益为18.9 dB,最大噪声系数为8.0 dB。 展开更多
关键词 喇曼光纤放大器 泵浦 增益 平坦度 仿真 OptiSystem
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一种加载耦合金属板的宽带蝶形天线的设计 认领
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作者 林月茹 林文斌 《电子测量技术》 2020年第6期15-20,共6页
设计了一种加载耦合金属板的宽带蝶形天线,该天线应用了4个独立放置的金属板来增大天线的带宽和增益,并采用折叠型反射板以获取稳定的辐射方向图和较平坦的增益曲线。金属板围绕天线的辐射器,与辐射器耦合,使天线产生了新的谐振频率点,... 设计了一种加载耦合金属板的宽带蝶形天线,该天线应用了4个独立放置的金属板来增大天线的带宽和增益,并采用折叠型反射板以获取稳定的辐射方向图和较平坦的增益曲线。金属板围绕天线的辐射器,与辐射器耦合,使天线产生了新的谐振频率点,从而改善天线在工作频带内的阻抗特性。反射板采用折叠的形式,不仅能有效抑制旁瓣,还能达到改善高频处的增益的目的。通过HFSS软件对天线进行仿真,得到天线的结构参数,并分析引入结构对天线性能的影响。仿真结果表明,天线尺寸为42 mm×29 mm×23.6 mm,当S11≤-10 dB,天线工作频段为2.35~4.52 GHz,相对带宽为63.2%,增益为4.4~6.45 dBi。 展开更多
关键词 蝶形天线 宽带 耦合金属板 折叠型接地板 S11 增益
24GHz高增益超材料覆层型微带天线的拓扑优化设计 认领
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作者 董焱章 周精浩 《重庆大学学报:自然科学版》 EI CAS CSCD 北大核心 2020年第6期50-57,共8页
提出了一种基于遗传算法的高增益超材料覆层型微带天线拓扑优化设计方法,设计中对超材料基元和辐射基元采用整体考量的方法,选取微带天线的最大增益值为目标函数,选取超材料覆铜区域离散化后方格子铜贴片的二进制0-1编码为优化变量,建立... 提出了一种基于遗传算法的高增益超材料覆层型微带天线拓扑优化设计方法,设计中对超材料基元和辐射基元采用整体考量的方法,选取微带天线的最大增益值为目标函数,选取超材料覆铜区域离散化后方格子铜贴片的二进制0-1编码为优化变量,建立了24 GHz超材料覆层型微带天线的拓扑优化模型。并采用贴片方格子的冗余设计方法来消除拓扑优化中的单点连接,进而通过合适的遗传算法求解策略对10×10方格子规模的优化设计问题进行求解,获得了一种不含单点连接的新型超材料覆层型微带天线。结果表明,与普通微带天线相比,创新构型的超材料覆层型微带天线具有更佳的工作频率匹配性能,微带天线的增益性能和方向性得到明显提升,其最大增益性能从7.51 dB提升到11.54 dB,提升了53.66%。最后对比研究了12×12和14×14等两种不同方格子规模的超材料微带天线拓扑优化设计问题,结果显示得到的创新构型优化设计结果是趋于收敛的,考虑到制备性价比,10×10方格子规模下的创新构型是制备最佳选择。 展开更多
关键词 超材料 微带天线 增益 拓扑优化
高增益的微波光子变频智能控制方法 认领
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作者 刘伟 刘志芳 《激光杂志》 北大核心 2020年第8期191-195,共5页
针对当前微波光子变频控制方法中存在的信号增益及动态范围较小等问题,提出基于级联强制信号调制器的高增益微波光子变频智能控制方法。深入分析变频处理后所得中频信号中存在的三阶交调失真情况,在此基础上,通过调节光电探测器的响应... 针对当前微波光子变频控制方法中存在的信号增益及动态范围较小等问题,提出基于级联强制信号调制器的高增益微波光子变频智能控制方法。深入分析变频处理后所得中频信号中存在的三阶交调失真情况,在此基础上,通过调节光电探测器的响应度、光载波信号的输出功率以及调制器输入信号的振幅来抑制变频信号的三阶交调,分析不同偏置相移与本振信号功率的关系,对比微波光子变频控制方法优化前后情况,得出优化后的微波光子变频智能控制方法的三阶交调抑制效果更好。实验结果表明,高增益微波光子变频智能控制方法能够有效完成信号变频控制,且其三阶交调抑制效果更好,能够为实践应用提供一定的理论依据。 展开更多
关键词 微波光子 增益 变频 智能控制 调制
外调制微波光传输链路性能优化研究 认领
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作者 吴骅 左朋勃 龙飞 《数字通信世界》 2020年第4期17-19,共3页
微波光传输链路(MWPL)具有损耗小、容量大、重量轻、抗干扰能力强等优点,已在军事、雷达、无线通信等领域得到广泛应用.决定微波光传输链路性能的参数主要有链路增益、噪声系数和动态范围.文章首先通过建模分析,推导出了增益和噪声系数... 微波光传输链路(MWPL)具有损耗小、容量大、重量轻、抗干扰能力强等优点,已在军事、雷达、无线通信等领域得到广泛应用.决定微波光传输链路性能的参数主要有链路增益、噪声系数和动态范围.文章首先通过建模分析,推导出了增益和噪声系数的关系,研究了微波光传输系统噪声系数的各种影响因素.通过仿真与实验验证表明,合理的调节调制器输入光功率,可提高链路增益,同时降低链路噪声系数,优化传输链路的性能. 展开更多
关键词 微波光链路 外调制 增益 噪声系数
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一种正六边形嵌套分形超宽带天线的设计 认领
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作者 严冬 张力弓 +2 位作者 王平 程威 易兆 《微波学报》 CSCD 北大核心 2020年第2期32-36,共5页
针对当前超宽带天线存在的方向性差、增益小的现状,提出了一种正六边形嵌套分形的超宽带天线。天线利用嵌套分形结构的自相似性和空间填充特性,有效拓展带宽,缩减天线尺寸。通过对天线维数进行仿真分析,选择带宽满足超宽带指标的四维和... 针对当前超宽带天线存在的方向性差、增益小的现状,提出了一种正六边形嵌套分形的超宽带天线。天线利用嵌套分形结构的自相似性和空间填充特性,有效拓展带宽,缩减天线尺寸。通过对天线维数进行仿真分析,选择带宽满足超宽带指标的四维和五维天线;对四维天线和五维天线的E-H面方向图及增益进行对比得知,五维天线较高增益由方向图畸变产生,故选择方向性更好的四维天线为此次设计的目标天线。目标天线尺寸仅为20 mm×23 mm×1.6 mm,带宽为2.7~10.6 GHz,增益为1.8~7.8 dBi,且天线实现了良好阻抗匹配。与引文其它天线相比,目标天线具有较小的尺寸,同时具有良好的方向性和较高的增益。天线实测结果与仿真基本吻合,验证了其研究与应用价值。 展开更多
关键词 正六边形 嵌套分形结构 超宽带 增益 方向性
Semi-Global Consensus Problems of Discrete-Time Multi-Agent Systems in the Presence of Input Constraints 认领
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作者 王健 时良仁 《上海交通大学学报:英文版》 EI 2020年第3期288-298,共11页
This paper studies the consensus problems of the discrete-time multi-agent systems (MASs) in the presence of input saturation constraints over directed communication networks.Two kinds of consensus problems,of the lea... This paper studies the consensus problems of the discrete-time multi-agent systems (MASs) in the presence of input saturation constraints over directed communication networks.Two kinds of consensus problems,of the leaderless consensus problem with no leader agent and the containment control problem with multiple leader agents,are investigated in this paper.Low gain feedback consensus algorithms based on the improved discretetime parametric algebraic Riccati equation (ARE) are proposed to solve the consensus problems.For the MAS without any leader,the trajectories of all agents converge together when the communication networks contain a directed spanning tree.For the MAS with multiple leaders,the trajectories of all follower agents converge to the convex hull spanned by the leader agents when there is at least one leader agent which is trackable for each follower agent.Simulation examples are provided to verify the theoretical results. 展开更多
关键词 leaderless consensus containment control DISCRETE-TIME low gain input saturation
Reversion of weak-measured quantum entanglement state 认领
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作者 杜少将 彭勇刚 +3 位作者 冯海冉 韩峰 杨连武 郑雨军 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第7期308-312,共5页
We theoretically study the reversible process of quantum entanglement state by means of weak measurement and corresponding reversible operation.We present a protocol of the reversion operation in two bodies based on t... We theoretically study the reversible process of quantum entanglement state by means of weak measurement and corresponding reversible operation.We present a protocol of the reversion operation in two bodies based on the theory of reversion of single photon and then expend it in quantum communication channels.The theoretical results demonstrate that the protocol does not break the information transmission after a weak measurement and a reversible measurement with the subsequent process in the transmission path.It can reverse the perturbed entanglement intensity evolution to its original state.Under the condition of different weak measurement intensity the protocol can reverse the perturbed quantum entanglement system perfectly.In the process we can get the classical information described by information gain from the quantum system through weak measurement operation.On the other hand,in order to realize complete reversibility,the classical information of the quantum entanglement system must obey a limited range we present in this paper in the reverse process. 展开更多
关键词 quantum entanglement weak measurement reversion operation information gain and reversibility
基于微带馈电的介质杆天线设计 认领 被引量:1
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作者 周向远 马润波 +1 位作者 张骄 刘宇峰 《测试技术学报》 2020年第1期89-92,共4页
设计了一种新型的基于微带贴片馈电的介质谐振器天线.天线的介质杆设计为锥削结构,采用具有嵌入式微带线的圆形贴片进行馈电.通过调节微带线嵌入圆形贴片的深度和宽度,获得较宽的阻抗带宽.天线样品的测试结果与设计仿真结果吻合良好.天... 设计了一种新型的基于微带贴片馈电的介质谐振器天线.天线的介质杆设计为锥削结构,采用具有嵌入式微带线的圆形贴片进行馈电.通过调节微带线嵌入圆形贴片的深度和宽度,获得较宽的阻抗带宽.天线样品的测试结果与设计仿真结果吻合良好.天线阻抗带宽(|S11|<-10dB)为7.1%(5.73~6.14GHz),频段内的平均增益超过11.1dBi.在工作频率5.8GHz处,天线的增益达到11.2dBi,相应的口径效率为84.1%. 展开更多
关键词 介质谐振器 增益 口径效率 宽频带 微带线
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复介质光量子阱光传输特性的增益效应 认领
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作者 苏安 蒙成举 +3 位作者 赵宏斌 唐秀福 黄晓萍 高英俊 《激光与红外》 CAS CSCD 北大核心 2020年第6期736-742,共7页
利用传输矩阵法,研究复介质光量子阱光传输特性的增益效应机制,结果表明复介质对光量子阱内部局域电场和分立共振透射峰的透射率均具有增益放大作用:复介质光量子阱与实介质光量子阱一样,内部也存在很强的局域电场以及透射谱中也出现分... 利用传输矩阵法,研究复介质光量子阱光传输特性的增益效应机制,结果表明复介质对光量子阱内部局域电场和分立共振透射峰的透射率均具有增益放大作用:复介质光量子阱与实介质光量子阱一样,内部也存在很强的局域电场以及透射谱中也出现分立的共振透射峰,但复介质光量子阱的内部局域电场和分立共振透射峰会出现增益放大现象。在光量子阱的组成介质A中掺入具有增益效应的激活性杂质时,光量子阱的内部局域电场首先随着激活性杂质含量的增加而放大增强,但增益放大到极大值后又开始衰减下降,而且不同入射光波长,光量子阱内部局域电场增益放大的极大值及其对应的激活杂质含量不同,其中对处于短波方向的光入射时内部局域电场对激活杂质含量的响应最灵敏最高,而且内部局域电场增益放大的极大值最大,对处于长波方向的光入射时内部局域电场对激活杂质含量的响应灵敏度最低,内部局域电场增益放大的极大值最小。复介质光量子阱光传输特性的增益效应机制,对新型光学滤波器、光学放大器和激光器等光学器件的理论研究与实际设计,以及光量子阱光传输特性的内在机制研究等,均具有积极的指导意义。 展开更多
关键词 复介质光量子阱 增益 局域电场 透射谱 光子晶体
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动力定位与起重机联合控制系统剖析 认领
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作者 余小青 《中国设备工程》 2020年第12期112-113,共2页
随着国家海洋战略的深入,海洋效益进一步凸显,开发海洋资源已成为必然趋势,目前,市场上出现了一种带动力定位(DP)系统的全回转起重船,该船型能够承接海上作业平台的吊装、拆解、转移任务,也可以承接大型桥梁钢结构的安装及海上风机的维... 随着国家海洋战略的深入,海洋效益进一步凸显,开发海洋资源已成为必然趋势,目前,市场上出现了一种带动力定位(DP)系统的全回转起重船,该船型能够承接海上作业平台的吊装、拆解、转移任务,也可以承接大型桥梁钢结构的安装及海上风机的维护等任务,由于其优异的作业性能,同类型船数量也呈逐年上升趋势。该船型能够在复杂海况下实现DP系统和全回转起重机联合作业,在海况及吊重重量等不确定因素下最大限度保障船舶的作业安全。本篇将重点剖析DP系统和起重机联合作业的原理及特点。 展开更多
关键词 动力定位(DP) 零增益区(Zero Gain) 全球定位系统(GPS)
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Clinical characteristics and prognostic values of 1p32.3 deletion detected through fluorescence in situ hybridization in patients with newly diagnosed multiple myeloma: a single-center study in China 认领
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作者 Huanping Wang Haitao Meng +8 位作者 Jinghan Wang Yinjun Lou Yile Zhou Peipei Lin Fenglin Li Lin Liu Huan Xu Min Yang Jie Jin 《医学前沿:英文版》 SCIE CAS CSCD 2020年第3期327-334,F0004,共9页
This study aimed to investigate the prevalence,clinical characteristics,and prognostic impact of 1p32.3 deletion in patients with newly diagnosed multiple myeloma (MM).A retrospective analysis was conducted on 411 pat... This study aimed to investigate the prevalence,clinical characteristics,and prognostic impact of 1p32.3 deletion in patients with newly diagnosed multiple myeloma (MM).A retrospective analysis was conducted on 411 patients with newly diagnosed MM;among which,270 received bortezomib-based therapies,and 141 received thalidomide-based therapies.Fluorescence in situ hybridization (FISH) was performed to detect six cytogenetic abnormalities,namely,del(1p32.3),gain(1q21),del(17p13),del(13q14),t(4;14),and t(11;14).Results showed that 8.3% of patients with MM were detected with del(1p32.3) and had significantly more bone marrow plasma cells (P =0.025),higher β2-microglobulin levels (P =0.036),and higher lactate dehydrogenase levels (P =0.042) than those without del(1p32.3).Univariate analysis showed that patients with del(1p32.3) under thalidomide-based therapies were strongly associated with short progression-free survival (PFS) (median PFS 11.6 vs.31.2 months,P =0.002) and overall survival (OS) (median OS 16.8 vs.45.9 months,P < 0.001).Multivariate analysis revealed that del(1p32.3) remained a powerful independent factor with worse PFS (P =0.006) and OS (P =0.016) for patients under thalidomide-based treatments.Patients with del(1 p32.3) under bortezomib-based treatments tended to have short PFS and OS.In conclusion,del(1p32.3) is associated with short PFS and OS in patients with MM who received thalidomide-or bortezomib-based treatments. 展开更多
关键词 1p32.3 deletion 1q21 gain prognosis multiple myeloma FISH BORTEZOMIB THALIDOMIDE
Gain-induced large optical torque in optical twist settings 认领
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作者 李艮艳 李肖 +1 位作者 张磊 陈君 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第8期264-269,共6页
Inducing a significant optical torque remains a challenging task,since the law of angular momentum conservation implies that one has to harvest a lot of light.Such a problem was partially resolved by using optical twi... Inducing a significant optical torque remains a challenging task,since the law of angular momentum conservation implies that one has to harvest a lot of light.Such a problem was partially resolved by using optical twist via strong internal multiple scattering to recycle the photons,and one can induce a large torque per unit of radiation cross section.By using the Maxwell stress tensor and the generalized Lorentz-Mie scattering theory for multi-spheres,we investigate the influence of gain materials in further amplifying optical torque in the optical twist settings.It is found that,when combined with a gain layer,the optical torque of lossy(both in PT-and non-PT-symmetric structures)or lossless(low dielectric materials)clusters at resonance could be one order of magnitude larger than those of a single layer and previous studied plasmonic double layer structures.Moreover,the gain-enhanced large opposite rotations(i.e.,optical twist)of the two layers arise at resonances in these structures.In contrast,in the gain-gain double-layer cluster,optical torques on both layers have no significant increase and the two layers rotate in the same direction at resonances.This work provides an elaborate investigation on the gain media-induced optical twist,which offers more choices for optical micromanipulation. 展开更多
关键词 optical torque optical twist gain medium double-layer clusters
Fractionally Delayed Kalman Filter 认领
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作者 Abhinoy Kumar Singh 《自动化学报:英文版》 EI CSCD 2020年第1期169-177,共9页
The conventional Kalman filter is based on the assumption of non-delayed measurements. Several modifications appear to address this problem, but they are constrained by two crucial assumptions: 1) the delay is an inte... The conventional Kalman filter is based on the assumption of non-delayed measurements. Several modifications appear to address this problem, but they are constrained by two crucial assumptions: 1) the delay is an integer multiple of the sampling interval, and 2) a stochastic model representing the relationship between delayed measurements and a sequence of possible non-delayed measurements is known. Practical problems often fail to satisfy these assumptions, leading to poor estimation accuracy and frequent track-failure. This paper introduces a new variant of the Kalman filter, which is free from the stochastic model requirement and addresses the problem of fractional delay.The proposed algorithm fixes the maximum delay(problem specific), which can be tuned by the practitioners for varying delay possibilities. A sequence of hypothetically defined intermediate instants characterizes fractional delays while maximum likelihood based delay identification could preclude the stochastic model requirement. Fractional delay realization could help in improving estimation accuracy. Moreover, precluding the need of a stochastic model could enhance the practical applicability. A comparative analysis with ordinary Kalman filter shows the high estimation accuracy of the proposed method in the presence of delay. 展开更多
关键词 Index Terms—Gaussian LIKELIHOOD KALMAN filter optimal KALMAN GAIN randomly DELAYED measurements
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安宁疗护试点病房护士工作体验研究 认领
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作者 赵敬 张艳 +6 位作者 王昱 许阳 杜灿灿 李宏洁 李思思 田雨同 刘珍 《护理学杂志》 CSCD 北大核心 2020年第11期56-59,共4页
目的深入了解安宁疗护试点病房护士的真实工作体验,为完善相关管理机制提供参考。方法选取全国首批安宁疗护试点病房的12名护士进行半结构式访谈,采用Colaizzi七步法分析资料,提炼主题。结果提炼出收获与成长、压力与挑战、需求与期待3... 目的深入了解安宁疗护试点病房护士的真实工作体验,为完善相关管理机制提供参考。方法选取全国首批安宁疗护试点病房的12名护士进行半结构式访谈,采用Colaizzi七步法分析资料,提炼主题。结果提炼出收获与成长、压力与挑战、需求与期待3个主题及其9个类属。结论护士感受到收获与压力并存;应加强专项培训,完善各项支持与管理机制,提高民众对安宁疗护认知等,以使安宁疗护顺利开展。 展开更多
关键词 护士 安宁疗护 病房 工作体验 收获 压力 挑战 质性研究
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