In this paper, we propose a novelmethod based on the plate theory to simultaneously predict retention times and peak shapes under gradient elutions and different flow rates by reversed-phase high-performance liquid ch...In this paper, we propose a novelmethod based on the plate theory to simultaneously predict retention times and peak shapes under gradient elutions and different flow rates by reversed-phase high-performance liquid chromatography. The proposed method yielded excellent retention prediction results in experiments with 16 common sulfonamides under 18 gradient conditions and four different flow rates, including 0.7, 1.0, 1.3, and 1.5 mL/min. The mean absolute deviation was 0.70%, which indicates accurate prediction. Moreover, the proposed method predicts the change wellin peak shapes caused by the expansion or compression ofpeaks under different gradient conditions.展开更多
The peak shapes ofT-rays at various energies must be known before unfolding the multiplet spectra obtained by using semiconductor or scintillation detectors. Traditional methods describe isolated peaks with multi-para...The peak shapes ofT-rays at various energies must be known before unfolding the multiplet spectra obtained by using semiconductor or scintillation detectors. Traditional methods describe isolated peaks with multi-parameter fitting functions, and assume that most of these parameters do not vary with energy because it is rare to find a spectrum with enough isolated peaks to constrain their dependence. We present an algorithm for interpolating the T-ray profile at any intermediate energy given a pair of isolated T-ray peaks from the spectrum under consideration. The algorithm is tested on experimental data and leads to a good agreement between the interpolated profile and the fitting function. This method is more accurate than the traditional approach, since all aspects of the peak shape are allowed to vary with energy. New definitions of Left-Half Width at Half Maximum, and Right-Half Width at Half Maximum for peak shape description are introduced in this paper.展开更多
The aim of this work is the development of a steganographic technique for the MP3 audio format, which is based on the Peak Shaped Model algorithm used for JPEG images. The proposed method relies on the statistical pro...The aim of this work is the development of a steganographic technique for the MP3 audio format, which is based on the Peak Shaped Model algorithm used for JPEG images. The proposed method relies on the statistical properties of MP3 samples, which are compressed by a Modified Discrete Cosine Transform (MDCT). After the conversion of MP3, it’s possible to hide some secret information by replacing the least significant bit of the MDCT coefficients. Those coefficients are chosen according to the statistical relevance of each coefficient within the distribution. The performance analysis has been made by calculating three steganographic parameters: the Embedding Capacity, the Embedding Efficiency and the PSNR. It has been also simulated an attack with the Chi-Square test and the results have been used to plot the ROC curve, in order to calculate the error probability. Performances have been compared with performances of other existing techniques, showing interesting results.展开更多
Sensitivity loop shaping using add-on peak filters is a simple and effective method to reject narrow-band disturbances in hard disk drive （HDD） servo systems. The parallel peak filter is introduced to provide high-g...Sensitivity loop shaping using add-on peak filters is a simple and effective method to reject narrow-band disturbances in hard disk drive （HDD） servo systems. The parallel peak filter is introduced to provide high-gain magnitude in the concerned frequency range of open-loop transfer function. Different from almost all the known peak filters that possess second-order structures, we explore in this paper bow high-order peak filters can be designed to improve the loop shaping performance. The main idea is to replace some of the constant coefficients of common second-order peak filter by frequency-related transfer functions, and then differential evolution （DE） algorithm is adopted to perform optimal design. We creatively introduce chromosome coding and fitness function design, which are original and the key steps that lead to the success of DE applications in control system design. In other words, DE is modified to achieve a novel design for hard disk drive control. Owing to the remarkable searching ability of DE, the expected shape of sensitivity function can be achieved by incorporating the resultant high-order peak filter in parallel with baseline feedback controller. As a result, a seventh-order peak filter is designed to compensate for contact-induced vibration in a high-density HDD servo system, where the benefits of high-order filter are clearly demonstrated.展开更多
1. Introduction CuZnAl shape memory alloys have beenextensively studied as a new type of material.Dejonghe[1]et al. firstly reported theirresults on the internal friction (IF) of CuZnAlalloys in 1975. Later, some rese...1. Introduction CuZnAl shape memory alloys have beenextensively studied as a new type of material.Dejonghe[1]et al. firstly reported theirresults on the internal friction (IF) of CuZnAlalloys in 1975. Later, some researchershave done much work on internal friction.But most of them were concerned withphase transformation internal frictionof martensite and reverse martensite andfew of them were about internal friction展开更多
针对分布式电源和新型负荷容量累积造成负荷影响因素多元化和不确定性特性增强的问题,文中提出一种采用记忆神经网络和曲线形状修正的负荷预测方法。在负荷峰值预测中,采用最大信息系数计算负荷峰值与影响因素的非线性相关性,实现对输...针对分布式电源和新型负荷容量累积造成负荷影响因素多元化和不确定性特性增强的问题,文中提出一种采用记忆神经网络和曲线形状修正的负荷预测方法。在负荷峰值预测中,采用最大信息系数计算负荷峰值与影响因素的非线性相关性,实现对输入特征的筛选;综合考虑负荷峰值序列的长短期自相关性和输入特征与负荷峰值的不同程度相关性,结合Attention机制和双向长短时记忆(bidirectional long short-term memory,BiLSTM)神经网络建立负荷峰值预测模型。在负荷标幺曲线预测中,通过误差倒数法组合相似日和相邻日,建立负荷标幺曲线预测模型;针对预测偏差的非平稳特征,利用自适应噪声的完全集成经验模态分解和BiLSTM网络建立误差预测模型,对曲线形状进行修正。应用中国北方某城市的区域电网负荷数据为算例,验证了所提模型的有效性。展开更多
气力输送是散体物料清洁高效输送的重要途径,然而弯管磨损制约着煤炭气力输送工业化应用,其中弯管形状结构是影响磨损的重要因素之一,基于此提出一种具有弧形堵头结构的新型弯管。首先,在DN50的管道系统中进行7~11mm煤炭颗粒气力输送试...气力输送是散体物料清洁高效输送的重要途径,然而弯管磨损制约着煤炭气力输送工业化应用,其中弯管形状结构是影响磨损的重要因素之一,基于此提出一种具有弧形堵头结构的新型弯管。首先,在DN50的管道系统中进行7~11mm煤炭颗粒气力输送试验,气流速度为20m/s,供气压力保持0.4MPa,弧形堵头圆弧角分别为10°、20°、30°和40°,无量纲高度分别为0.4、0.6、0.8、1.0,利用共焦三维形貌仪测量管壁磨损分布及最大磨损深度;其次,通过欧拉–拉格朗日双边耦合的计算流体力学与离散元(Computational Fluid Dynamics–Discrete Element Method,CFD–DEM)方法建立数值模型,通过对最大磨损深度的仿真模拟与试验测量校验数值模型的科学性;最后,从磨损分布、磨损峰值、碰撞能量损失等方面研究了弧形堵头对弯管磨损的弱化特性,推演了弧形堵头弱化磨损的最优结构参数判据。结果表明:圆弧角是弧形堵头弱化弯管磨损的主要影响因素,当圆弧角不足20°时堵头无法包含全部磨损中心辐射区域,而当圆弧角超过40°时堵头底面难以被颗粒完全覆盖,上述2种条件下弧形堵头对弯管磨损的弱化作用均受限;盲通弯管磨损峰值及其增长率均低于普通弯管,当圆弧角为30°且无量纲高度为0.8时,磨损中心被分散至侧壁上的多个位置而避免了集中冲击,磨损峰值仅为普通弯管的25.1%;任意圆弧角的碰撞能量损失关于无量纲高度的变化曲线均包含1个提升段与2个平缓段,2个临界点依次代表颗粒开始覆盖堵头底面以及形成稳定堆积的高度。研究成果有利于解决长期存在的弯管磨损顽疾,为煤炭气力输送工业化应用提供理论依据,同时可推广至其他矿物颗粒输送领域。展开更多
基金supported by the National Nature Science Foundation of China (No. 51406109)
文摘In this paper, we propose a novelmethod based on the plate theory to simultaneously predict retention times and peak shapes under gradient elutions and different flow rates by reversed-phase high-performance liquid chromatography. The proposed method yielded excellent retention prediction results in experiments with 16 common sulfonamides under 18 gradient conditions and four different flow rates, including 0.7, 1.0, 1.3, and 1.5 mL/min. The mean absolute deviation was 0.70%, which indicates accurate prediction. Moreover, the proposed method predicts the change wellin peak shapes caused by the expansion or compression ofpeaks under different gradient conditions.
基金National Natural Science Foundation of China (10775006)Research Fund for Doctoral Program of Higher Education of China (20070001008)China Postdoctoral Science Foundation
文摘The peak shapes ofT-rays at various energies must be known before unfolding the multiplet spectra obtained by using semiconductor or scintillation detectors. Traditional methods describe isolated peaks with multi-parameter fitting functions, and assume that most of these parameters do not vary with energy because it is rare to find a spectrum with enough isolated peaks to constrain their dependence. We present an algorithm for interpolating the T-ray profile at any intermediate energy given a pair of isolated T-ray peaks from the spectrum under consideration. The algorithm is tested on experimental data and leads to a good agreement between the interpolated profile and the fitting function. This method is more accurate than the traditional approach, since all aspects of the peak shape are allowed to vary with energy. New definitions of Left-Half Width at Half Maximum, and Right-Half Width at Half Maximum for peak shape description are introduced in this paper.
文摘The aim of this work is the development of a steganographic technique for the MP3 audio format, which is based on the Peak Shaped Model algorithm used for JPEG images. The proposed method relies on the statistical properties of MP3 samples, which are compressed by a Modified Discrete Cosine Transform (MDCT). After the conversion of MP3, it’s possible to hide some secret information by replacing the least significant bit of the MDCT coefficients. Those coefficients are chosen according to the statistical relevance of each coefficient within the distribution. The performance analysis has been made by calculating three steganographic parameters: the Embedding Capacity, the Embedding Efficiency and the PSNR. It has been also simulated an attack with the Chi-Square test and the results have been used to plot the ROC curve, in order to calculate the error probability. Performances have been compared with performances of other existing techniques, showing interesting results.
基金supported by National Natural Science Foundation of China(Nos.61640310 and 61433011)
文摘Sensitivity loop shaping using add-on peak filters is a simple and effective method to reject narrow-band disturbances in hard disk drive （HDD） servo systems. The parallel peak filter is introduced to provide high-gain magnitude in the concerned frequency range of open-loop transfer function. Different from almost all the known peak filters that possess second-order structures, we explore in this paper bow high-order peak filters can be designed to improve the loop shaping performance. The main idea is to replace some of the constant coefficients of common second-order peak filter by frequency-related transfer functions, and then differential evolution （DE） algorithm is adopted to perform optimal design. We creatively introduce chromosome coding and fitness function design, which are original and the key steps that lead to the success of DE applications in control system design. In other words, DE is modified to achieve a novel design for hard disk drive control. Owing to the remarkable searching ability of DE, the expected shape of sensitivity function can be achieved by incorporating the resultant high-order peak filter in parallel with baseline feedback controller. As a result, a seventh-order peak filter is designed to compensate for contact-induced vibration in a high-density HDD servo system, where the benefits of high-order filter are clearly demonstrated.
文摘1. Introduction CuZnAl shape memory alloys have beenextensively studied as a new type of material.Dejonghe[1]et al. firstly reported theirresults on the internal friction (IF) of CuZnAlalloys in 1975. Later, some researchershave done much work on internal friction.But most of them were concerned withphase transformation internal frictionof martensite and reverse martensite andfew of them were about internal friction
文摘针对分布式电源和新型负荷容量累积造成负荷影响因素多元化和不确定性特性增强的问题,文中提出一种采用记忆神经网络和曲线形状修正的负荷预测方法。在负荷峰值预测中,采用最大信息系数计算负荷峰值与影响因素的非线性相关性,实现对输入特征的筛选;综合考虑负荷峰值序列的长短期自相关性和输入特征与负荷峰值的不同程度相关性,结合Attention机制和双向长短时记忆(bidirectional long short-term memory,BiLSTM)神经网络建立负荷峰值预测模型。在负荷标幺曲线预测中,通过误差倒数法组合相似日和相邻日,建立负荷标幺曲线预测模型;针对预测偏差的非平稳特征,利用自适应噪声的完全集成经验模态分解和BiLSTM网络建立误差预测模型,对曲线形状进行修正。应用中国北方某城市的区域电网负荷数据为算例,验证了所提模型的有效性。
文摘气力输送是散体物料清洁高效输送的重要途径,然而弯管磨损制约着煤炭气力输送工业化应用,其中弯管形状结构是影响磨损的重要因素之一,基于此提出一种具有弧形堵头结构的新型弯管。首先,在DN50的管道系统中进行7~11mm煤炭颗粒气力输送试验,气流速度为20m/s,供气压力保持0.4MPa,弧形堵头圆弧角分别为10°、20°、30°和40°,无量纲高度分别为0.4、0.6、0.8、1.0,利用共焦三维形貌仪测量管壁磨损分布及最大磨损深度;其次,通过欧拉–拉格朗日双边耦合的计算流体力学与离散元(Computational Fluid Dynamics–Discrete Element Method,CFD–DEM)方法建立数值模型,通过对最大磨损深度的仿真模拟与试验测量校验数值模型的科学性;最后,从磨损分布、磨损峰值、碰撞能量损失等方面研究了弧形堵头对弯管磨损的弱化特性,推演了弧形堵头弱化磨损的最优结构参数判据。结果表明:圆弧角是弧形堵头弱化弯管磨损的主要影响因素,当圆弧角不足20°时堵头无法包含全部磨损中心辐射区域,而当圆弧角超过40°时堵头底面难以被颗粒完全覆盖,上述2种条件下弧形堵头对弯管磨损的弱化作用均受限;盲通弯管磨损峰值及其增长率均低于普通弯管,当圆弧角为30°且无量纲高度为0.8时,磨损中心被分散至侧壁上的多个位置而避免了集中冲击,磨损峰值仅为普通弯管的25.1%;任意圆弧角的碰撞能量损失关于无量纲高度的变化曲线均包含1个提升段与2个平缓段,2个临界点依次代表颗粒开始覆盖堵头底面以及形成稳定堆积的高度。研究成果有利于解决长期存在的弯管磨损顽疾,为煤炭气力输送工业化应用提供理论依据,同时可推广至其他矿物颗粒输送领域。
