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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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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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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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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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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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基于临汾地震监测中心站钻孔应变的远震动态应力波动特征分析
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作者 陈永前 刘瑞春 +3 位作者 陈慧 李颖 魏凯艳 郝宇琦 《山西地震》 2025年第4期18-26,共9页
2025年1月7日西藏定日县发生的6.8级地震,给当地造成重大人员伤亡和财产损失,深入研究此次地震的发震机制、破裂过程及应力演化特征具有重要意义。本文选取临汾地震监测中心站四分量钻孔应仪变记录到的100 Hz地震波形资料,从震相识别、... 2025年1月7日西藏定日县发生的6.8级地震,给当地造成重大人员伤亡和财产损失,深入研究此次地震的发震机制、破裂过程及应力演化特征具有重要意义。本文选取临汾地震监测中心站四分量钻孔应仪变记录到的100 Hz地震波形资料,从震相识别、正应力花瓣图及动态库仑应力变化计算等方面对此次地震的动态波形特征进行分析。结果显示,从钻孔应变动态记录的P波、S波和面波震相到时与地震台网的一致。应力花瓣图显示多数台站观测到P波、S波和面波的主应力方向与地震波入射方向有较高一致性。对于定日地震,面波造成临汾地震监测中心站的库仑应力幅值在1 kPa左右。此次地震后,1月10日在临汾市尧都区发生了4.1级地震,但从临汾地区受到的动态库仑应力大小和持续时间看,尧都地震作为滞后触发的可能性很小。研究结果不仅可对传统地震仪观测提供补充和验证,更可丰富对地震应力波传播及影响的科学认识。 展开更多
关键词 钻孔应变台阵 正应力花瓣图 应变震级 震相识别 动态库仑应变变化
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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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反反相色谱-串联质谱法直接测定植物源性食品中草甘膦及其代谢物残留 被引量:24
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作者 周爽 徐敦明 +3 位作者 林立毅 陈鹭平 周昱 杨黎忠 《分析测试学报》 CAS CSCD 北大核心 2013年第2期199-204,共6页
采用反反相色谱-串联质谱法建立了直接测定植物源性食品中草甘膦(GLY)及其主要代谢物氨甲基膦酸(AMPA)的方法。样品用水提取,阴离子交换柱(MAX)净化,以5 mmol/L的乙酸铵溶液和5%水-95%乙腈的乙酸铵溶液为流动相,反反相色谱分离,采用电... 采用反反相色谱-串联质谱法建立了直接测定植物源性食品中草甘膦(GLY)及其主要代谢物氨甲基膦酸(AMPA)的方法。样品用水提取,阴离子交换柱(MAX)净化,以5 mmol/L的乙酸铵溶液和5%水-95%乙腈的乙酸铵溶液为流动相,反反相色谱分离,采用电喷雾离子源、负离子扫描模式和多反应监测模式质谱检测,外标法定量。草甘膦和氨甲基膦酸的线性范围分别为10~500μg/L和20~1 000μg/L,相关系数(r2)均大于0.99。方法的检出限(S/N=3)均为0.01 mg/kg,定量下限(S/N=10)分别为0.02 mg/kg和0.04 mg/kg。在6种基质中,GLY和AMPA在3个加标水平下的回收率为78%~113%,相对标准偏差(RSD,n=6)为3.2%~11.0%。方法的灵敏度和回收率高,选择性好,能满足日常食品检测工作的要求。 展开更多
关键词 草甘膦 氨甲基膦酸 反反相色谱 液相色谱-串联质谱法 阴离子交换柱
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超声提取正相高效液相色谱法测定大豆及大豆油中的磷酸甘油酯 被引量:10
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作者 王秀嫔 李培武 +2 位作者 张文 陈小媚 俞理 《分析测试学报》 CAS CSCD 北大核心 2011年第5期527-531,共5页
建立了超声提取-固相萃取纯化/正相高效液相色谱测定大豆及大豆油中磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、磷脂酰肌醇(PI)的方法。考察了提取溶剂、超声功率、超声时间、提取温度及净化方式的影响,并研究了不同色谱固定相对磷酸甘油酯分... 建立了超声提取-固相萃取纯化/正相高效液相色谱测定大豆及大豆油中磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、磷脂酰肌醇(PI)的方法。考察了提取溶剂、超声功率、超声时间、提取温度及净化方式的影响,并研究了不同色谱固定相对磷酸甘油酯分离效果的影响。优化的实验条件为:以氯仿-甲醇(2∶1,体积比)为提取溶剂,1 500 W功率超声提取30 min;氨基固相萃取柱为纯化小柱;正己烷-异丙醇-1%HAc(8∶8∶1,体积比)为流动相。在该条件下,PC、PE、PI的线性范围分别为0.08~8.00、0.15~15.00、0.30~20.00 g.L-1,定量下限分别为0.021、0.050、0.060 g.L-1,检出限在8~23 mg.L-1之间,其在大豆和大豆油中的回收率为85%~108%。日内与日间精密度分别不大于4.7%和8.6%。 展开更多
关键词 正相高效液相色谱 大豆 大豆油 超声提取 磷酸甘油酯
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固相萃取-高效液相色谱法测定生活污水中壬基酚聚氧乙烯醚及其降解产物 被引量:28
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作者 侯绍刚 胡智弢 +1 位作者 孙红文 黄国兰 《中国环境监测》 CAS CSCD 北大核心 2005年第4期10-13,共4页
比较了液-液萃取和固相萃取浓缩富集水体中壬基酚聚氧乙烯醚(NPnEO,n为聚合度)及其小分子代谢产物的效率,建立了复杂基体水样中壬基酚聚氧乙烯醚及其小分子代谢产物多成分同时测定的高分辨高灵敏的固相萃取(SPE)-正相高效液相色谱(NP-HP... 比较了液-液萃取和固相萃取浓缩富集水体中壬基酚聚氧乙烯醚(NPnEO,n为聚合度)及其小分子代谢产物的效率,建立了复杂基体水样中壬基酚聚氧乙烯醚及其小分子代谢产物多成分同时测定的高分辨高灵敏的固相萃取(SPE)-正相高效液相色谱(NP-HPLC)-荧光检测(FL)方法。优化了影响SPE回收率的条件,洗脱溶剂和样品过柱的速度。SPE对NPnEO的回收率大于82%;使用1L水样,方法的检测限对壬基酚(NP)、NP1EO为0.01μgL,NP2EO、NP3EO为0.02μgL,NP4EO~NP12EO为0.05μgL。应用本方法测定了生活污水水样,检测到了NPnEO(n=1~12)及其小分子降解产物NP、NP1EO、NP2EO。 展开更多
关键词 固相萃取 高效液相色谱 壬基酚聚氧乙烯醚 壬基酚
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