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Cosmology-Independent Photon Mass Limits from Localized Fast Radio Bursts by Using Artificial Neural Networks
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作者 冉景遇 王宝 魏俊杰 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第5期177-183,共7页
A hypothetical photon mass m_(γ) can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed di... A hypothetical photon mass m_(γ) can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed distance. The dispersion measure and redshift measurements of fast radio bursts(FRBs) have been widely used to constrain the rest mass of the photon. However, all current studies analyzed the effect of the frequency-dependent dispersion for massive photons in the standard ΛCDM cosmological context. In order to alleviate the circularity problem induced by the presumption of a specific cosmological model based on the fundamental postulate of the masslessness of photons, here we employ a new model-independent smoothing technique, artificial neural network(ANN), to reconstruct the Hubble parameter H(z) function from 34 cosmic-chronometer measurements.By combining observations of 32 well-localized FRBs and the H(z) function reconstructed by ANN, we obtain an upper limit of m_(γ) ≤ 3.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 2.0 × 10^(-15)eV/c^(2)(m_(γ) ≤ 6.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 3.6 × 10^(-15)eV/c_(2)) at the 1σ(2σ) confidence level. This is the first cosmology-independent photon mass limit derived from extragalactic sources. 展开更多
关键词 DISPERSION LIMIT independent
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A Constrained Local Neighborhood Approach for Efficient Markov Blanket Discovery in Undirected Independent Graphs
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作者 Kun Liu Peiran Li +4 位作者 Yu Zhang JiaRen Ming Li Xianyu Wang Cong Li 《Computers, Materials & Continua》 SCIE EI 2024年第8期2535-2555,共21页
When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm efficiency.Traditional constr... When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm efficiency.Traditional constraint-based methods typically rely on the results of conditional independence tests.However,excessive reliance on these test results can lead to a series of problems,including increased computational complexity and inaccurate results,especially when dealing with large-scale networks where performance bottlenecks are particularly evident.To overcome these challenges,we propose a Markov blanket discovery algorithm based on constrained local neighborhoods for constructing undirected independence graphs.This method uses the Markov blanket discovery algorithm to refine the constraints in the initial search space,sets an appropriate constraint radius,thereby reducing the initial computational cost of the algorithm and effectively narrowing the initial solution range.Specifically,the method first determines the local neighborhood space to limit the search range,thereby reducing the number of possible graph structures that need to be considered.This process not only improves the accuracy of the search space constraints but also significantly reduces the number of conditional independence tests.By performing conditional independence tests within the local neighborhood of each node,the method avoids comprehensive tests across the entire network,greatly reducing computational complexity.At the same time,the setting of the constraint radius further improves computational efficiency while ensuring accuracy.Compared to other algorithms,this method can quickly and efficiently construct undirected independence graphs while maintaining high accuracy.Experimental simulation results show that,this method has significant advantages in obtaining the structure of undirected independence graphs,not only maintaining an accuracy of over 96%but also reducing the number of conditional independence tests by at least 50%.This significant performance improvement is due to the effective constraint on the search space and the fine control of computational costs. 展开更多
关键词 Bayesian network structure learning Markov blanket conditional independence
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Origin of the Dashuigou independent tellurium deposit at Qinghai–Xizang Plateau: constraints from the light stable isotopes C, O, and H
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作者 Jianzhao Yin Yuhong Chao +2 位作者 Haoyu Yin Hongyun Shi Shoupu Xiang 《Acta Geochimica》 EI CAS CSCD 2024年第2期385-398,共14页
By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)... By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)O and δ^(13)C isotope signatures of dolomite samples vary between 10.2 and 13.0‰,and between−7.2 and−5.2‰,respectively,implying that the carbon derives from the upper mantle.δD and δ^(18) O of quartz,biotite,and muscovite from diff erent ore veins of the deposit vary between−82 and−59‰,and between 11.6 and 12.4‰,respectively,implying that the metallogenic solutions are mainly magmatic.According to the relevant research results of many isotope geologists,the fractionation degree of hydrogen isotopes increases as the depth to the Earth’s core increases,and the more diff erentiated the hydrogen isotopes are,the lower their values will be.In other words,mantle-derived solutions can have extremely low hydrogen isotope values.This means that the δD‰ value−134 of the pyrrhotite sample numbered SD-34 in this article may indicate mantle-derived oreforming fl uid of the deposit.The formation of the Dashuigou tellurium deposit occurred between 91.71 and 80.19 Ma. 展开更多
关键词 Carbon oxygen and hydrogen isotopes ORIGIN independent tellurium deposit The Qinghai–Xizang Plateau
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Are cities greener because of innovation?Independent innovation policy and green economic efficiency
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作者 Zhuoji Zheng Xueqin Li +3 位作者 Mengjie Yu Yuan Li Xianfeng Han Yuping Yin 《Chinese Journal of Population,Resources and Environment》 2024年第2期118-126,共9页
The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278... The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278 prefecture-level cities in China from 2006 to 2020 and empirically examines the effect and internal mechanism of the NIIDZ on green economic efficiency(GEE)using the difference-in-difference model(DID).The results show that the NIIDZ effectively enhances the growth of GEE,and the results remain valid through several robustness tests,such as year-by-year propensity score matching.The transmission mechanism suggests that the NIIDZ indirectly drives GEE by accelerating scientific and technological investment,promoting talent concentration,and optimizing the industrial structure.Moreover,heterogeneity analysis reveals that the promotion effect of the NIIDZ on GEE is more prominent in the eastern region and high green development level areas.The study’s findings can serve as a reference for China to further utilize the policy effectiveness of the NIIDZ and accelerate the high-quality development of the green economy in the future. 展开更多
关键词 National innovation independent demonstration Zone(NIIDZ) Green economy efficiency(GEE) Difference-in-difference model(DID)
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Study on Independent Supervision Function of Design Assurance System
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作者 SUI Lijun MA Congyao WANG Jianyuan 《International Journal of Plant Engineering and Management》 2024年第3期185-192,共8页
The effective operation of a design assurance system cannot be achieved without the effective performance of the independent supervision function.As one of the core functions of the design assurance system,the purpose... The effective operation of a design assurance system cannot be achieved without the effective performance of the independent supervision function.As one of the core functions of the design assurance system,the purpose of the independent supervision function is to ensure that the system operates within the scope of procedures and manuals.At present,the function of independent supervision is a difficult and confusing issue for various original equipment manufacturers as well as suppliers,and there is an urgent requirement to put forward relevant requirements and form relevant methods.Based on the above mentioned objective,the basic requirements of the independent supervision function of design assurance system were studied,the problems and deficiencies in the organization,staffing,and methods existing in the current independent supervision function were analyzed,the improvement suggestions and measures for the performance of the independent supervision function from the aspects of the organization,staffing,procedures,and suppliers were put forward.The present work and conclusions provide guidance and direction for the effective operation of the design assurance system. 展开更多
关键词 design of assurance systems independent supervision functions system operation internal audits SUPPLIERS
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Analysis of the Role of Problem-Based Independent Learning Model in Teaching Cerebral Ischemic Stroke First Aid in Emergency Medicine
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作者 Hua Liu 《Journal of Contemporary Educational Research》 2024年第6期16-21,共6页
Objective:To analyze the effect of using a problem-based(PBL)independent learning model in teaching cerebral ischemic stroke(CIS)first aid in emergency medicine.Methods:90 interns in the emergency department of our ho... Objective:To analyze the effect of using a problem-based(PBL)independent learning model in teaching cerebral ischemic stroke(CIS)first aid in emergency medicine.Methods:90 interns in the emergency department of our hospital from May 2022 to May 2023 were selected for the study.They were divided into Group A(45,conventional teaching method)and Group B(45 cases,PBL independent learning model)by randomized numerical table method to compare the effects of the two groups.Results:The teaching effect indicators and student satisfaction scores in Group B were higher than those in Group A(P<0.05).Conclusion:The use of the PBL independent learning model in the teaching of CIS first aid can significantly improve the teaching effect and student satisfaction. 展开更多
关键词 Problem-based independent learning model Emergency medicine Ischemic stroke First aid teaching SATISFACTION
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Three Dimensional Kinematics Analysis of the Independent Suspension Multibody System 被引量:2
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作者 陈欣 林逸 +1 位作者 孙大刚 白文辉 《Journal of Beijing Institute of Technology》 EI CAS 1997年第4期80-86,共7页
Based on the theory of multibody system dynamics, the spatial kinematics analysis of the Mcpherson independent suspension widely used in the car was carried out. A practical and simpler method was provided to reduce t... Based on the theory of multibody system dynamics, the spatial kinematics analysis of the Mcpherson independent suspension widely used in the car was carried out. A practical and simpler method was provided to reduce the number of the generalized coordinates and constraint functions. By solving the nonlinear equations, the motion of any points in the whole suspension and wheel system can be predicted, including the spatial changes of the wheel alignment parameters which are of great importance to the car performances. 展开更多
关键词 independent suspension three dimension kinematic analysis multibody system
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Modeling dam deformation using independent component regression method 被引量:3
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作者 戴吾蛟 刘斌 +1 位作者 丁晓利 黄大伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第7期2194-2200,共7页
In the application of regression analysis method to model dam deformation, the ill-condition problem occurred in coefficient matrix always prevents an accurate modeling mainly due to the multicollinearity of the varia... In the application of regression analysis method to model dam deformation, the ill-condition problem occurred in coefficient matrix always prevents an accurate modeling mainly due to the multicollinearity of the variables. Independent component regression (ICR) was proposed to model the dam deformation and identify the physical origins of the deformation. Simulation experiment shows that ICR can successfully resolve the problem of ill-condition and produce a reliable deformation model. After that, the method is applied to model the deformation of the Wuqiangxi Dam in Hunan province, China. The result shows that ICR can not only accurately model the deformation of the dam, but also help to identify the physical factors that affect the deformation through the extracted independent components. 展开更多
关键词 dam deformation analysis independent component regression principal component regression ill-condition problem interpreting of dam deformation
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Design of Tensile Strained InGaAsP/InGaAsP MQW for 1.55μm Polarization Independent Semiconductor Optical Amplifier
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作者 邱伟彬 何国敏 +1 位作者 董杰 王圩 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第1期11-17,共7页
The theoretical optimization of tensile strained InGaAsP/InGaAsP MQW for 1.55μm windows polarization-independent semiconductor optical amplifier is reported.The valence-band structure of the MQW is calculated by usin... The theoretical optimization of tensile strained InGaAsP/InGaAsP MQW for 1.55μm windows polarization-independent semiconductor optical amplifier is reported.The valence-band structure of the MQW is calculated by using k·p method,in which 6×6 Luttinger effective-mass Hamiltonian is taken into account.The polarization dependent optical gain is calculated with various well width,strain,and carrier density. 展开更多
关键词 semiconductor optical amplifier polarization independence MQW
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Research into the Application of Cooperative Learning to English Reading Teaching of Art Majors in Independent Colleges 被引量:1
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作者 李张燕 《海外英语》 2018年第13期236-239,共4页
This paper first stated some related theories of cooperative learning and English reading teaching.And then an applicationof cooperative learning in English reading teaching of art majors in independent college is imp... This paper first stated some related theories of cooperative learning and English reading teaching.And then an applicationof cooperative learning in English reading teaching of art majors in independent college is implemented based on these literature re-views.The aim of the experiment is to explore the impact of the application of cooperative learning strategies.It mainly discussedthe following questions:(1)Can the group cooperative learning improve students'reading achievement?(2)What factors contributeto the success/failure of cooperative learning?(3)What are the favorite cooperative learning models in reading classes?The experi-ment proved that cooperative learning does not truly improve art students’reading achievement in independent college,but it real-ly has a positive role in promoting the students'learning interest,motivation and emotional attitude.The experiment also indicatesthat cooperative learning is still a valuable teaching strategy for applying,and GI,LT,TGT and other cooperative learning modelare welcomed by classmates. 展开更多
关键词 independent COLLEGE ART Majors COOPERATIVE Learning English READING Teaching
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A maximum-independent-set-based channel allocation algorithm for multi-channel wireless networks
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作者 余旭涛 施小翔 曾绍祥 《Journal of Southeast University(English Edition)》 EI CAS 2015年第1期12-18,共7页
A channel allocation algorithm based on the maximum independent set is proposed to decrease network conflict and improve network performance. First, a channel allocation model is formulated and a series of the maximum... A channel allocation algorithm based on the maximum independent set is proposed to decrease network conflict and improve network performance. First, a channel allocation model is formulated and a series of the maximum independent sets (MISs) are obtained from a contention graph by the proposed approximation algorithm with low complexity. Then, a weighted contention graph is obtained using the number of contention vertices between two MISs as a weighted value. Links are allocated to channels by the weighted contention graph to minimize conflicts between independent sets. Finally, after channel allocation, each node allocates network interface cards (NICs) to links that are allocated channels according to the queue lengths of NICs. Simulations are conducted to evaluate the proposed algorithm. The results show that the proposed algorithm significantly improves the network throughput and decreases the end to end delay. 展开更多
关键词 wireless networks MULTI-CHANNEL channelaUocation maximum independent set
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LIMITED MEMORY BFGS METHOD BY USING LINEAR INDEPENDENT SEARCH DIRECTIONS
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作者 倪勤 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2001年第2期236-239,共4页
The degree of numerical linear independence is proposed and discussed. Based on this linear independence theory, a modified limited memory BFGS method is deve loped. Similar to the standard limited memory method, thi... The degree of numerical linear independence is proposed and discussed. Based on this linear independence theory, a modified limited memory BFGS method is deve loped. Similar to the standard limited memory method, this new method determines the new update by applying the updating formula m times to an initial positive diagonal matrix using the m previous pairs of the change in iteration and gradient. Besides the most recent pair of the change, which guarantees the quadratic termination, the choice of the other ( m -1) pairs of the change in the new method is dependent on the degree of numerical linear independence of previous search directions. In addition, the numerical linear independence theory is further discussed and the computation of the degree of linear independence is simplified. Theoretical and numerical results show that this new modified method improves efficiently the standard limited memory method. 展开更多
关键词 unconstrained optimization limited memory method BFGS method degree of linear independence
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A Brief Account of Independent College in China:Its Past and Further Development
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作者 何玲 《海外英语》 2013年第13期20-22,共3页
This article briefs the past and development of independent colleges until now in China,dealing with the reasons why they have come into existence and developed in a remarkable way.A somewhat detailed analysis of thei... This article briefs the past and development of independent colleges until now in China,dealing with the reasons why they have come into existence and developed in a remarkable way.A somewhat detailed analysis of their distinctions from other higher education has been made and the further development strategies are also presented in it. 展开更多
关键词 independent COLLEGES distinctions STRATEGIES devel
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To Improve Students'Linguistic Performance & Independent Thinking Abilities in Business English Teaching
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作者 李勇 《科教导刊》 2013年第23期129-130,共2页
Business English is a required course for English majors.By learning the course,students can know the necessary business knowledge and improve their linguistic performance and independent thinking abilities under the ... Business English is a required course for English majors.By learning the course,students can know the necessary business knowledge and improve their linguistic performance and independent thinking abilities under the systematic background knowledge of industry & business theory and practice.It will be the strong foundations for students'better future career. 展开更多
关键词 Business English linguistic performance independent thinking
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广义Independent Biclique攻击框架及其应用 被引量:2
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作者 崔竞一 郭建胜 刘翼鹏 《计算机学报》 EI CSCD 北大核心 2018年第2期349-367,共19页
该文对Biclique攻击框架及其实现方法进行了研究.Biclique攻击是一种结合Biclique初始结构与中间相遇攻击的一种攻击方法,有平衡Biclique攻击、非平衡Biclique攻击、Star攻击等多种攻击形式.该文提出了广义Biclique结构的概念,对Bicliqu... 该文对Biclique攻击框架及其实现方法进行了研究.Biclique攻击是一种结合Biclique初始结构与中间相遇攻击的一种攻击方法,有平衡Biclique攻击、非平衡Biclique攻击、Star攻击等多种攻击形式.该文提出了广义Biclique结构的概念,对Biclique结构重新进行了定义,涵盖了现有Biclique结构.同时提出了一种广义Biclique结构分类方式,按照维数分为高维Biclique结构与低维Biclique结构.通过进一步研究发现,高维Biclique结构可由低维Biclique结构直接构造得到,从而提出了一种高维Biclique结构构造方法,降低了结构构造过程的复杂度,同时利用该方法所得到的Biclique结构,结合计算与预计算技术,可以给出时间复杂度更优的Biclique攻击结果.在此基础上,设计并提出了一个广义Independent Biclique攻击框架,借助自动化实现技术能够面向比特构造出算法包括平衡Biclique结构、Star结构、非平衡Biclique结构在内的多种结构,同时能够给出算法在广义Biclique攻击下的安全性分析结果.最后,以LBlock算法为例,利用框架综合分析了其在Biclique攻击下的安全性,同时改进了AES-128算法基于Star结构的相关分析结果.获得分析结果如下:(1)针对LBlock算法,分别给出了两个低维Biclique攻击结果与两个高维Biclique攻击结果.构造了明文方向6轮4维的平衡Biclique结构,给出了数据复杂度更优的平衡Biclique攻击结果,其时间复杂度为2^(78.425)次全轮LBlock算法加密,数据复杂度为2^(40)选择明文;构造了明文方向6轮4维Star结构,给出了首个最低数据复杂度下全轮LBlock算法攻击结果,时间复杂度为2^(78.66)次全轮LBlock算法加密,数据复杂度为2个已知明文;构造了明文方向6轮8维平衡Biclique结构,给出了目前最优的全轮LBlock算法分析结果,其时间复杂度为2^(78.14)次全轮LBlock算法加密,数据复杂度为2^(60)个选择明文;构造了明文方向6轮规模2~4×2~8的非平衡Biclique结构,在2^(40)个选择明文条件下,给出了时间复杂度为2^(78.24)的全轮LBlock算法分析结果;(2)针对AES-128算法,改进了算法在Star攻击下的安全性.通过构造密文方向2.5轮Star结构代替明文方向的2轮Star结构,改进了最低数据复杂度下全轮AES-128的分析结果,其时间复杂度为2^(126.66)次全轮AES加密,数据复杂度为2个已知明文. 展开更多
关键词 Biclique攻击 independent Biclique结构 广义Biclique结构 攻击框架 AES算法 LBlock算法
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The Integration of Sports Specialty English and College English Teaching in the Independent Colleges
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作者 吴园园 《疯狂英语(理论版)》 2017年第4期112-113,共2页
At the present time,there are many imbalances in sports specialty English teaching in the independent colleges such as emphasis on basic English teaching while ignoring sports specialty English teaching, unreasonable ... At the present time,there are many imbalances in sports specialty English teaching in the independent colleges such as emphasis on basic English teaching while ignoring sports specialty English teaching, unreasonable application of modern information technology, imbalance of English teachers' knowledge structure in sports specialty, etc. As for the English teaching in sports specialty in the independent college,it is necessary to build college English curriculum system with the attributes of sports education. 展开更多
关键词 Sports Specialty English College English Teaching the independent Colleges
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High Extinction Ration Polarization Independent EA Modulator 被引量:1
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作者 孙洋 王圩 +3 位作者 陈娓兮 刘国利 周帆 朱洪亮 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第11期1374-1376,共3页
An electro absorption modulator is fabricated for optical network system.The strained InGaAs/InAlAs MQW shows improved modulation properties,including polarization independent,high extinction ratio (>40dB) and low... An electro absorption modulator is fabricated for optical network system.The strained InGaAs/InAlAs MQW shows improved modulation properties,including polarization independent,high extinction ratio (>40dB) and low capacitance (<0 5pF),with which,an ultra high frequency(>10GHz) can be obtained. 展开更多
关键词 electro absorption MODULATOR polarization independence
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Interpretation of Independent Personality in Jane Eyre
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作者 刘芳琼 《海外英语》 2020年第15期226-227,235,共3页
A very successful image of feminism is created in this novel:Jane Eyre,written by Charlotte Bronte.Jane Eyre grows up from a penniless and pathetic girl into a totally independent new woman economically and emotionall... A very successful image of feminism is created in this novel:Jane Eyre,written by Charlotte Bronte.Jane Eyre grows up from a penniless and pathetic girl into a totally independent new woman economically and emotionally.This essay will introduce the background and the purpose of writing Jane Eyre,then take the independent personality of Jane Eyre as the main body and explore her feminist consciousness,end with some enlightenment from the independent personality in Jane Eyre. 展开更多
关键词 PERSONALITY independENCE ENLIGHTENMENT
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Source Separation of Diesel Engine Vibration Based on the Empirical Mode Decomposition and Independent Component Analysis 被引量:21
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作者 DU Xianfeng LI Zhijun +3 位作者 BI Fengrong ZHANG Junhong WANG Xia SHAO Kang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第3期557-563,共7页
Vibration signals from diesel engine contain many different components mainly caused by combustion and mechanism operations,several blind source separation techniques are available for decomposing the signal into its ... Vibration signals from diesel engine contain many different components mainly caused by combustion and mechanism operations,several blind source separation techniques are available for decomposing the signal into its components in the case of multichannel measurements,such as independent component analysis(ICA).However,the source separation of vibration signal from single-channel is impossible.In order to study the source separation from single-channel signal for the purpose of source extraction,the combination method of empirical mode decomposition(EMD) and ICA is proposed in diesel engine signal processing.The performance of the described methods of EMD-wavelet and EMD-ICA in vibration signal application is compared,and the results show that EMD-ICA method outperforms the other,and overcomes the drawback of ICA in the case of single-channel measurement.The independent source signal components can be separated and identified effectively from one-channel measurement by EMD-ICA.Hence,EMD-ICA improves the extraction and identification abilities of source signals from diesel engine vibration measurements. 展开更多
关键词 empirical mode decomposition independent component analysis source separation single-channel signal
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Preliminary Discussion on the ESP Teaching for Civil Engineering Majors of Independent Colleges 被引量:1
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作者 张宏亮 蔡虹 顾正谊 《海外英语》 2015年第20期237-238,240,共3页
In independent colleges, English for civil engineering majors is not a main course. Accompanied by China's accession to WTO and the deepening global economic integration, civil engineering industry enhances intern... In independent colleges, English for civil engineering majors is not a main course. Accompanied by China's accession to WTO and the deepening global economic integration, civil engineering industry enhances international exchanges and cooperation.In order to further adapt to the international community and the market demand, English for civil engineering majors is becoming more and more important to the graduates who graduate from this major. Discussion on the English teaching situation and the existing issues for civil engineering majors of independent colleges from teaching methods, by putting forward some suggestions, help to improve English teaching level of civil engineering majors of independent colleges. 展开更多
关键词 independent COLLEGE CIVIL engineering English TEACHING SITUATION TEACHING method
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