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Preparative isolation of Heteroclitin D from Kadsurae Caulis using normal-phase flash chromatography 被引量:2
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作者 Xiao-Xue Yu Qian-Wen Wang +3 位作者 Xin-Jun Xu Wei-Jian Lv Ming-Qian Zhao Zhi-Kun Liang 《Journal of Pharmaceutical Analysis》 SCIE CAS 2013年第6期456-459,共4页
Heteroclitin D (H.D) was successfully isolated from Kadsurae Caulis by using flash chromatography and recrystalllzed by methanol, 10.2 mg of H.D was obtained from 4.86 g of crude extract, and the purity determined b... Heteroclitin D (H.D) was successfully isolated from Kadsurae Caulis by using flash chromatography and recrystalllzed by methanol, 10.2 mg of H.D was obtained from 4.86 g of crude extract, and the purity determined by HPLC was 99.4%. The structure was identified by UV, IR, MS, and NMR analysis. The fast, simple and efficient method can be applied to the preparation of reference substance of H. D. 展开更多
关键词 Kadsurae Caulis Heteroclitin D normal-phase flashchromatography
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S Phase Cell Percentage Normalized BrdU Incorporation Rate, a New Parameter for Determining S Arrest 被引量:2
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作者 ZHAO Peng FU Juan Ling +2 位作者 YAO Bi Yun JIA Yong Rui ZHOU Zong Can 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2014年第3期215-219,共5页
In this study, a new parameter, S phase cell percentage (S fraction) normalized BrdU (SFN-BrdU) incorporation rate, was introduced to detect $ arrest. The results showed a positive linear correlation between the B... In this study, a new parameter, S phase cell percentage (S fraction) normalized BrdU (SFN-BrdU) incorporation rate, was introduced to detect $ arrest. The results showed a positive linear correlation between the BrdU incorporation rate and the S fraction in unperturbed 16HBE cells. Theoretical analysis indicated that only S arrest could result in a decrease in the SFN-BrdU incorporation rate. Additionally, the decrease in SFN-BrdU incorporation rate and the activation of DNA damage checkpoints further demonstrated that S arrest was induced by diethyl sulfate treatment of 16HBE cells. In conclusion, $FN-BrdU incorporation rate can be used to detecting S arrest. 展开更多
关键词 BRDU RATE S phase Cell Percentage normalized BrdU Incorporation Rate a New Parameter for Determining S Arrest
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ORIGINAL ARTICLE Development and validation of a normal-phase HPTLC method for the simultaneous analysis of Lamivudine and Zidovudine in fixed-dose combination tablets
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作者 Palani Venkatesh Mahesh Daggumati 《Journal of Pharmaceutical Analysis》 SCIE CAS 2012年第2期152-155,共4页
Simultaneous quantification of Lamivudine and Zidovudine in tablets by HPTLC method was developed and validated.The chromatograms were developed using a mobile phase of toluene:ethyl acetate:methanol (4:4:2,v/v/v) on ... Simultaneous quantification of Lamivudine and Zidovudine in tablets by HPTLC method was developed and validated.The chromatograms were developed using a mobile phase of toluene:ethyl acetate:methanol (4:4:2,v/v/v) on pre-coated plate of silica gel GF aluminum TLC plate and quantified by densitometric absorbance mode at 276 nm.The R f values were 0.4170.03 and 0.6070.04 for Lamivudine and Zidovudine,respectively.The linearity of the method was found to be within the concentration range of 50 250 ng/spot for Lamivudine and for Zidovudine,it was 100 500 ng/spot.The lower limits of detection and quantification were 2.23 ng/spot and 7.90 ng/spot for Lamivudine and 2.90 ng/spot and 8.85 ng/spot for Zidovudine.The method was also validated for precision,specificity and recovery.This developed method was used to analyze fixed-dose tablets (Duovir,Cipla Ltd) samples of Lamivudine and Zidovudine. 展开更多
关键词 normal-phase HPTLC LAMIVUDINE ZIDOVUDINE METHANOL
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Effect of normalized plasma frequency on electron phase-space orbits in a free-electron laser 被引量:2
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作者 吉驭嫔 王时建 +5 位作者 徐竟跃 徐勇根 刘晓旭 卢宏 黄小莉 张世昌 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第2期242-246,共5页
Irregular phase-space orbits of the electrons are harmful to the electron-beam transport quality and hence deteriorate the performance of a free-electron laser (FEL). In previous literature, it was demonstrated that... Irregular phase-space orbits of the electrons are harmful to the electron-beam transport quality and hence deteriorate the performance of a free-electron laser (FEL). In previous literature, it was demonstrated that the irregularity of the electron phase-space orbits could be caused in several ways, such as varying the wiggler amplitude and inducing sidebands. Based on a Hamiltonian model with a set of self-consistent differential equations, it is shown in this paper that the electron- beam normalized plasma frequency functions not only couple the electron motion with the FEL wave, which results in the evolution of the FEL wave field and a possible power saturation at a large beam current, but also cause the irregularity of the electron phase-space orbits when the normalized plasma frequency has a sufficiently large value, even if the initial energy of the electron is equal to the synchronous energy or the FEL wave does not reach power saturation. 展开更多
关键词 free-electron laser electron phase-space orbit normalized plasma frequency IRREGULARITY
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基于规范形方法的并网变换器系统暂态同步稳定分析
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作者 刘其辉 李开心 +2 位作者 蔡希鹏 朱益华 罗超 《电力自动化设备》 北大核心 2025年第6期116-123,共8页
锁相环(PLL)在电压源型变换器(VSC)并网系统中的非线性动力学特性,给新型电力系统的暂态同步稳定性分析带来了挑战,特别是在强非线性系统中。为此,针对具有较强非线性PLL的VSC并网系统,建立其暂态响应的2阶微分方程,并基于规范形方法推... 锁相环(PLL)在电压源型变换器(VSC)并网系统中的非线性动力学特性,给新型电力系统的暂态同步稳定性分析带来了挑战,特别是在强非线性系统中。为此,针对具有较强非线性PLL的VSC并网系统,建立其暂态响应的2阶微分方程,并基于规范形方法推导PLL输出相位的解析解。在此基础上,分析系统的同步稳定机理,提出新的暂态稳定判据,揭示影响暂态同步稳定性的关键因素及规律。研究结果表明,VSC有功出力、电网电感、PLL的比例积分参数是影响暂态同步稳定性的主要因素。基于MATLAB/Simulink进行仿真与实验以验证所提方法的有效性,结果表明该方法能够提高电力系统暂态稳定性分析的准确性与可靠性。 展开更多
关键词 并网变换器 非线性分析 规范形方法 锁相环 暂态同步稳定性
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一种干涉仪线阵解模糊错误判断方法
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作者 居易 张秋实 +2 位作者 陈文静 翟羽佳 宋明翰 《现代雷达》 北大核心 2025年第8期78-83,共6页
干涉仪测向系统依据相位差进行方位解算,单个信号进行方位解算时,相位差解模糊错误不可避免。针对该问题,文中提出了一种判断干涉仪线阵解模糊错误方法。在得到相位差计算值后,针对干涉仪线阵中的每个基线,计算该基线对应的相位差测量... 干涉仪测向系统依据相位差进行方位解算,单个信号进行方位解算时,相位差解模糊错误不可避免。针对该问题,文中提出了一种判断干涉仪线阵解模糊错误方法。在得到相位差计算值后,针对干涉仪线阵中的每个基线,计算该基线对应的相位差测量值与相位差计算值的差值,并进行归一化处理。将所有基线对应的归一化相位差误差进行累加,与门限值比较,从而判断当前信号解模糊是否存在较大错误概率。依据干涉仪测向系统布阵建立抽屉取球模型,对归一化相位差误差概率分布进行计算,所选取的门限值符合小概率事件原则。该算法计算量小,适合用于实时计算。该方法能够为后续数据处理提供依据,提高系统的测向准确性。仿真验证表明,该方法判断准确性较高,效果明显。 展开更多
关键词 干涉仪 解模糊 错误判断 归一化相位差误差
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Self-normal and biorthogonal dynamical quantum phase transitions in non-Hermitian quantum walks
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作者 Haiting Zhang Kunkun Wang +1 位作者 Lei Xiao Peng Xue 《Light(Science & Applications)》 2025年第9期2674-2684,共11页
Dynamical quantum phase transitions(DQPTs),characterized by non-analytic behavior in rate function and abrupt changes in dynamic topological order parameters(DTOPs)over time,have garnered enormous attention in recent ... Dynamical quantum phase transitions(DQPTs),characterized by non-analytic behavior in rate function and abrupt changes in dynamic topological order parameters(DTOPs)over time,have garnered enormous attention in recent decades.However,in non-Hermitian systems,the special biorthogonality of the bases makes the definition of DQPTs complex.In this work,we delve into the comprehensive investigation of self-normal DQPTs(originally used in Hermitian systems)to compare them with their biorthogonal counterpart,within the context of non-Hermitian quantum walks(QWs).We present a detailed analysis of the behaviors of Loschmidt rate functions and DTOPs under these two distinct theoretical approaches.While both self-normal and biorthogonal methods can be used to detect DQPTs in quench dynamics between different topological phases,we theoretically present their differences in the definition of critical momenta and critical times by analyzing the Fisher zeros and fixed points.Finally,we present an experiment that observes both types of DQPTs using one-dimensional discrete-time QWs with single photons. 展开更多
关键词 self normal dynamical quantum phase transitions non hermitian quantum walks hermitian systems fixed points dynamical quantum phase transitions dqpts characterized Loschmidt rate functions dynamic topological order parameters Fisher zeros
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融合FBPBPF和NTFT的极移弱周期分量提取及其激发原因分析
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作者 王辰晨 徐工 +3 位作者 苏晓庆 张英琦 赵亚鑫 穆峥 《地球物理学进展》 北大核心 2025年第3期905-912,共8页
地球极移中周期分量的时变特征是其物理激发机制研究的基础,极移主要成分——钱德勒摆动和周年摆动已得到了充分的研究.随着极移观测质量大幅度提高,使得研究极移中弱周期分量的时变特征也成为可能.傅里叶基追踪带通滤波(Fourier Basis ... 地球极移中周期分量的时变特征是其物理激发机制研究的基础,极移主要成分——钱德勒摆动和周年摆动已得到了充分的研究.随着极移观测质量大幅度提高,使得研究极移中弱周期分量的时变特征也成为可能.傅里叶基追踪带通滤波(Fourier Basis Pursuit Band Pass Filter, FBPBPF)具有克服边缘效应的优势,能够避免周年摆动和钱德勒摆动等周期成分的影响;标准时频变换(Normal Time-Frequency Transform, NTFT)能够无偏地确定周期分量的即时振幅、即时频率和即时相位,为研究弱周期分量的时变特征奠定基础.采用融合FBPBPF和NTFT的方法,以准500 dW为例,精确提取极移中准500 dW,首次给出准500 dW周期随时间变化,周期范围为482~502天;提取曼巴赫站、梅迪奇纳站和莫莎站的重力数据中的周期成分,该融合方法可以清晰的看出三个台站均存在约500天左右的周期成分,与极移中准500 dW的周期浮动范围相似;从核幔耦合角度,准500 dW的相位与三个台站叠加后的相位存在相关性,进一步验证地球内核变化是影响极移的原因,该研究为地球深内部结构和动力学过程提供研究基础. 展开更多
关键词 地球内核 弱周期分量 标准时频变换 滤波 时变特征 相位
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气井弹性二相法基本原理、简化应用中的注意问题及建议
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作者 孙贺东 朱松柏 +5 位作者 姚超 赵龙飞 曹雯 曹文 杨小英 李梦勤 《天然气工业》 北大核心 2025年第5期79-86,共8页
弹性二相法作为计算气驱、低渗气藏单井控制范围内地质储量、技术可采储量的方法,在天然气勘探阶段估算探井控制储量或投产初期核实气藏储量时发挥着重要的作用,但标准中常用的简化公式未给出适用条件,导致气井单井控制储量出现偏差。为... 弹性二相法作为计算气驱、低渗气藏单井控制范围内地质储量、技术可采储量的方法,在天然气勘探阶段估算探井控制储量或投产初期核实气藏储量时发挥着重要的作用,但标准中常用的简化公式未给出适用条件,导致气井单井控制储量出现偏差。为此,基于有界气藏中一口直井在拟稳定流动阶段的无量纲解析解,详细推导给出了气井弹性二相法压力法、压力平方法、拟压力法和规整化拟压力法形式的有量纲计算公式,对表达式简化过程中存在的问题进行了分析,并提出了解决方案,最后分别进行了模拟实例和矿场实例的综合验证。研究结果表明:①当地层压力低于20.1 MPa时气体压缩系数可简化为1/pi,弹性二相法计算公式可进行简化;②当地层压力高于20.1 MPa时,应直接采用原始压力或计算最高压力情形下的气体压缩系数值,或采用1/pi简化与修正系数并举的方式;③(规整化)拟压力法是首选方法,低压(<13.8 MPa)情形不宜采用压力法。结论认为:①对于低渗、致密气藏,经常出现流压与时间呈线性关系但未达到拟稳定流动的现象,此时应慎用弹性二相法;②若有压力恢复数据,建议将压降与压力恢复数据(反褶积分析)结合起来评价储量。 展开更多
关键词 有界气藏 拟稳定流动 弹性二相法 压力法 压力平方法 拟压力法 规整化拟压力法 气体压缩系数
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磁靶向相变微胶囊/纳米Al_(2)O_(3)/环氧树脂复合绝缘材料的自修复特性 被引量:1
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作者 孙魄韬 王河飞 +2 位作者 司马文霞 牛朝露 唐文旭 《电工技术学报》 北大核心 2025年第13期4032-4044,共13页
环氧树脂等聚合物绝缘材料在长期电热老化以及机械应力作用下会产生微尺度损伤,诱发绝缘失效,严重威胁装备运行安全。针对此问题,该文设计了一种由固体二十八烷作为修复剂的磁靶向相变微胶囊,通过将微胶囊与常温固化型环氧树脂基体复合... 环氧树脂等聚合物绝缘材料在长期电热老化以及机械应力作用下会产生微尺度损伤,诱发绝缘失效,严重威胁装备运行安全。针对此问题,该文设计了一种由固体二十八烷作为修复剂的磁靶向相变微胶囊,通过将微胶囊与常温固化型环氧树脂基体复合,实现材料对微尺度损伤的靶向自主修复。首先在定向磁场作用下将微胶囊吸引至复合材料易损伤部位,当微损伤发展到微胶囊时,可在带电条件下人工施加红外辐射靶向加热损伤部位的微胶囊,使其迅速熔化并修复损伤通道;同时,引入Al_(2)O_(3)纳米粒子作为基体填充介质,可增强复合材料的绝缘性能与导热性能。研究结果表明:微胶囊粒径分布均匀,具有良好的热稳定性能;磁靶向诱导技术可在保持基材良好本征性能的同时提升材料的自修复效率;纳米Al_(2)O_(3)粒子的掺杂使得复合材料对红外辐射靶向加热具有良好的热响应特性;复合材料能够对机械划痕损伤自主修复,绝缘强度可恢复至未损伤时的90.78%。 展开更多
关键词 常温固化型环氧树脂 微损伤 自修复 磁靶向 相变微胶囊 纳米Al_(2)O_(3)
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动态法向应力振幅对散体材料摩擦特性影响研究
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作者 党文刚 郑俊滔 陈俊鹏 《地下空间与工程学报》 北大核心 2025年第2期461-471,共11页
散体颗粒材料被广泛应用于基础设施工程建设中。为了深入研究动态法向应力振幅对散体材料剪切滑移特性的影响,本文以标准干砂为研究对象,采用大型动态直剪试验机对标准砂进行变法向应力剪切试验。结果表明:(1)剪切应力、摩擦系数以及法... 散体颗粒材料被广泛应用于基础设施工程建设中。为了深入研究动态法向应力振幅对散体材料剪切滑移特性的影响,本文以标准干砂为研究对象,采用大型动态直剪试验机对标准砂进行变法向应力剪切试验。结果表明:(1)剪切应力、摩擦系数以及法向位移均伴随着法向力的改变呈周期性变化;(2)随动态法向应力振幅的增大,稳定滑移阶段剪切应力的峰值和谷值均先增大后减小,最大峰值剪切应力大于静态法向应力下峰值剪切应力;(3)剪切应力峰值与法向应力峰值间存在一个明显的相位差,该相位差随着剪切变形的增大而减小,随着动态法向应力振幅的增大而增大,然而剪切应力谷值与法向应力谷值间却不存在相位差;(4)动态法向应力下的法向位移随振幅的增大而增大,且远大于恒定法向应力下的法向位移。研究可为实际工程中动力荷载条件下下砂土强度参数的确定提供参考。 展开更多
关键词 散体颗粒材料 动态法向应力振幅 直剪试验 剪切应力 相位差
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Methodology of Wavelets in Relativistic Heavy Ion Collisions in One Dimensional Phase Space (<i>η</i>-Space) 被引量:1
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作者 Vyacheslav V. Lyashenko M. Ayaz Ahmad +1 位作者 Zhanna V. Deineko Mir Hashim Rasool 《Journal of High Energy Physics, Gravitation and Cosmology》 2017年第2期254-266,共13页
An attempt has been made to apply the wavelet methodology for the study of the results of the chaotic behavior of multiparticle production in relativistic heavy ion collisions. We reviewed the data that describes the ... An attempt has been made to apply the wavelet methodology for the study of the results of the chaotic behavior of multiparticle production in relativistic heavy ion collisions. We reviewed the data that describes the collisions of relativistic heavy ion for the case η-space in 1-D phase space of variable. We compared the experimental data and UrQMD data using wavelet coherency. We discussed the results of the comparison. 展开更多
关键词 WAVELET Coherence Morlet WAVELET Heavy Ion Collisions Reaction Dynamics phase Space normalized FACTORIAL MOMENTS
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A Powerful Optimization Technique for the Calculation of Binary Phase Diagrams Using Partial Phase Diagram Data
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作者 金展鹏 杜勇 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1989年第3期186-190,共5页
The interaction parameters for various phases in the Ti-W and Pd-W systems were calcula- ted using phase diagram information by means of a numerical procedure.The approach differs significantly from the trial and erro... The interaction parameters for various phases in the Ti-W and Pd-W systems were calcula- ted using phase diagram information by means of a numerical procedure.The approach differs significantly from the trial and error method and has the advantage of being very robust in the sense that one can make full use of the accurate experimental phase diagram data and deal with situations which are difficult or even impossible for the trial and error method. Using calculated parameters and lattice stability values for Ti,W and Pd given in literature, the diagrams of the above systems were recalcula- ted.The results are in good agreement with experimental information. 展开更多
关键词 OPTIMIZATION phase diagram normal distribution spline function
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Study of Wavelet Methodology and Chaotic Behavior of Produced Particles in Different Phase Spaces of Relativistic Heavy Ion Collisions
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作者 M. Ayaz Ahmad Vyacheslav V. Lyashenko +2 位作者 Zhanna V. Deineko Jalal Hasan Baker Shafiq Ahmad 《Journal of Applied Mathematics and Physics》 2017年第5期1130-1149,共20页
We applied the wavelet methodology for our earlier published research work of the chaotic behavior so called multiplicity fluctuations of secondary charged particles produced during the nucleus-nucleus (A-A) collision... We applied the wavelet methodology for our earlier published research work of the chaotic behavior so called multiplicity fluctuations of secondary charged particles produced during the nucleus-nucleus (A-A) collisions at an energy of the order of ≈ 409 GeV in a new fashion. We illustrated the wavelet coherency in a relation of chaotic behavior for above said data of secondary charged pions in different phase spaces of collisions such as: η-space, φ-space (in one dimension) and ηφ-space (in two dimensions) respectively. We have shown the changes in the wavelet coherence when there are different values of two parameters “q” and “p”. We discussed our new results for the comparison purpose and findings were in the good agreements. 展开更多
关键词 WAVELET Coherence Morlet WAVELET Dynamics of Nucleus-Nucleus (A-A) Collisions phase Space normalized FACTORIAL Moments (SFMs)
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正态漏斗附近水沙数值模拟 被引量:1
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作者 孙志林 朱贺贺 +1 位作者 连辉乾 丁凯旋 《中国农村水利水电》 北大核心 2024年第1期165-170,共6页
针对水库淤积问题,设计了一种正态漏斗排沙装置,在水槽中开展水流试验。对正态漏斗附近水流-泥沙进行欧拉两相流模拟,用水流试验数据对数值模型进行验证,进而分析了不同边界条件下流速、涡量和相浓度场。结果表明,漏斗内部流速梯度较大... 针对水库淤积问题,设计了一种正态漏斗排沙装置,在水槽中开展水流试验。对正态漏斗附近水流-泥沙进行欧拉两相流模拟,用水流试验数据对数值模型进行验证,进而分析了不同边界条件下流速、涡量和相浓度场。结果表明,漏斗内部流速梯度较大,泥沙相浓度等值线呈V型不对称分布,漏斗前缘、左后侧和右后侧出现大涡量区。与锥形漏斗对比,正态漏斗近壁面流速大,水流阻力小,3种边界条件下平均涡量减小25.8%~27.2%,出口泥沙相浓度增大15.2%~16.5%,具有降低能量耗散、显著提高排沙效率的作用。 展开更多
关键词 两相流 水沙 正态漏斗 数值模拟 水库
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Trichromatic phase manipulation of the response of a two-level medium to an arbitrarily intense probe field
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作者 郭洪菊 胡响明 +3 位作者 李景艳 李晓霞 石文星 徐清 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第2期383-388,共6页
The phase dependence and independence of the response of a trichromatieally driven two-level medium to an arbitrarily intense probe field have been studied. The sum of the relative phases of the sideband components of... The phase dependence and independence of the response of a trichromatieally driven two-level medium to an arbitrarily intense probe field have been studied. The sum of the relative phases of the sideband components of the trichromatic field compared to the central component plays a crucial role in the response of the medium. For a weak probe field, as the sum of the relative phases changes from 0 to π, multiple switching can be achieved, in which switching from normal to anomalous dispersion occurs in multiple separate frequency regimes. The remarkable dependence on the sum phase is also shown for a strong probe field. On the other hand, when the sum of the two relative phases is fixed, the changes in the respective phases have no influence on the response of the medium. 展开更多
关键词 absorption and dispersion phase dependence and independence multiple switching from normal to anomalous dispersion
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Effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids by using the Lord-Shulman and dual-phase-lag models 被引量:3
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作者 S.M.ABO-DAHAB A.M.ABD-ALLA A.A.KILANY 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2019年第8期1135-1154,共20页
The effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids in a generalized thermoplastic half-space are studied by using the Lord-Shulman (L-S) model and the dual-phase-la... The effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids in a generalized thermoplastic half-space are studied by using the Lord-Shulman (L-S) model and the dual-phase-lag (DPL) model. The analytical solutions for the displacements, stresses, temperature, diffusion concentration, and volume fraction field with different values of the magnetic field, the rotation, the gravity, and the initial stress are obtained and portrayed graphically. The results indicate that the effects of gravity, rotation, voids, diffusion, initial stress, and electromagnetic field are very pronounced on the physical properties of the material. 展开更多
关键词 electromagnetic field GRAVITY field ROTATION initial stress voids DIFFUSION normal mode analysis Lord-Shulman (L-S) model dual-phase-lag (DPL) model
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取向硅钢不同常化工艺下组织及抑制剂的变化 被引量:2
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作者 杨伟阳 黎先浩 +3 位作者 赵鹏飞 于海彬 赵松山 罗海文 《金属学报》 SCIE EI CAS CSCD 北大核心 2024年第5期605-615,共11页
常化是高磁感取向硅钢生产中的重要环节,通常认为通过控制常化工序中900℃开始的缓冷阶段,可实现γ→α相变来促进抑制剂的弥散析出进而改善磁性能,而本工作在系统研究了高磁感取向硅钢常化工艺中的升温速率、固溶温度、相变等温温度与... 常化是高磁感取向硅钢生产中的重要环节,通常认为通过控制常化工序中900℃开始的缓冷阶段,可实现γ→α相变来促进抑制剂的弥散析出进而改善磁性能,而本工作在系统研究了高磁感取向硅钢常化工艺中的升温速率、固溶温度、相变等温温度与时间、相变后冷却速率等参数对常化组织和抑制剂的影响后,对此有不同的发现。常化前的初始组织由以珠光体为主的富C片层和片层之间大量分布的铁素体所组成,在常化的加热与固溶过程中,只有碳化物片层区发生奥氏体相变,且提高固溶温度、延长固溶时间可形成更多奥氏体,但在1120℃固溶3 min依然无法完全溶解碳化物且不同区域内所形成奥氏体C浓度不均匀,奥氏体水冷后转变为马氏体和残余奥氏体。组织观察、原位膨胀实验结果与热力学计算结果均表明,在1120℃固溶后冷却至900~950℃相变温度保温时继续发生奥氏体化,而非普遍认为的γ→α相变,因此此时并不能通过该相变促进抑制剂析出。取向硅钢中细小抑制剂有2种来源:一是在铁素体区域由于降温导致抑制剂形成元素的固溶度下降而析出;二是900℃以下空冷时发生珠光体相变时析出。另外,提高加热速率和固溶温度均可溶解更多已形成的抑制剂,从而可在冷却时再析出更多的细小抑制剂。常化后抑制剂的类型主要为AlN、AlN与MnS的复合析出物及TiN。 展开更多
关键词 取向硅钢 常化 组织演变 抑制剂 相变
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永磁同步电机改进型全阶滑模观测器无传感控制 被引量:11
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作者 宋建国 李子豪 刘小周 《电机与控制应用》 2024年第1期14-21,共8页
针对传统全阶滑模观测器在运行过程中系统抖振大及观测精度低的问题,提出了一种可控边界层的全阶滑模控制策略。引入归一化锁相环进行转速估计,避免参数变化对估计值的影响,使转子位置识别更加精确。利用Lyapunov方程证明了算法的稳定... 针对传统全阶滑模观测器在运行过程中系统抖振大及观测精度低的问题,提出了一种可控边界层的全阶滑模控制策略。引入归一化锁相环进行转速估计,避免参数变化对估计值的影响,使转子位置识别更加精确。利用Lyapunov方程证明了算法的稳定性。最后通过仿真和试验验证了改进型全阶滑模观测器无传感控制策略的可靠性和准确性。 展开更多
关键词 永磁同步电机(PMSM) 全阶滑模 变边界层 归一化锁相环
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钛渣熔盐氯化用熔盐体系物相及物性研究
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作者 徐健淋 何艺霖 +5 位作者 马占山 庞忠亚 田丰 张学强 邹星礼 朱福兴 《钢铁钒钛》 CAS 北大核心 2024年第2期20-27,共8页
熔盐氯化法是针对高钙镁钛渣物料而开发的一种四氯化钛制备技术,在长期的生产实践中,发现氯化炉组分控制不当时熔盐会发生严重泡沫化,甚至出现影响生产的喷盐等现象。对此,采用XRD、SEM&EDS、DSCTGA等方法对正常盐和泡沫盐的成分、... 熔盐氯化法是针对高钙镁钛渣物料而开发的一种四氯化钛制备技术,在长期的生产实践中,发现氯化炉组分控制不当时熔盐会发生严重泡沫化,甚至出现影响生产的喷盐等现象。对此,采用XRD、SEM&EDS、DSCTGA等方法对正常盐和泡沫盐的成分、物相及物性进行深入研究。结果表明,泡沫盐中的氧含量以及水不溶固相物远高于正常盐,固相多以Na_(2)Al_(0.5)Fe_(9.5)O_(15)、Mg_(1.6)Ti_(1.1)O_(4)等复合氧化物形式存在。泡沫盐在300~1280℃的失重率为48.71%,较正常盐低13.73%,熔点呈增大趋势。泡沫盐中氧含量较正常盐高约10%,经高温挥发后残余物为富含铁、镁、铝、硅、钙、氧等元素的不规则颗粒团聚体,而正常盐的残余物则为铁、镁和氧元素均匀分布的致密体。阿基米德法无法满足含固相物的正常盐和泡沫盐密度测定,但可采用体积密度法进行测定,两者密度分别为2.02 g/cm^(3)和1.77 g/cm^(3)。 展开更多
关键词 钛渣 熔盐氯化 物相 正常盐 泡沫盐
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