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文章速递Analysis of Speeds of Cylinders of Saw Gins and Linters and Determination of Critical Frequencies for them 认领
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作者 Akramjon Sarimsakov 《工程(英文)》 SCIE EI 2020年第10期715-722,共8页
With an increase in the density of the seed roll in the roll box of the saw gin, the quality indicators of the fiber and seed are poor, energy consumption increases, machine breakdowns increase, and when the density d... With an increase in the density of the seed roll in the roll box of the saw gin, the quality indicators of the fiber and seed are poor, energy consumption increases, machine breakdowns increase, and when the density decreases, the performance of the saw gin increases. Therefore, the density control of the seed roll is one of the important problems in the ginning process. The paper proposes a change in the rotation speed of the saw cylinder with a decrease in the diameter of its numerical linear speed and machine productivity. The article describes the problem of regulating the density of a seed roll in a saw gin of the DP series, provides an overview of work on regulating the operation of the machine, determines the dependence of the productivity of gins and linters on the state of the saw system in these machines, as well as changes in the linear speed of the saw by changing its diameter. Also, the critical speed of the gin and linter saw cylinder was determined to prevent resonance. In this case, the Simulation package of the SolidWorks computer program was used. The results of the study made it possible to adjust the speed of the cylinders when changing the diameter of the saws, which improved the productivity of the machine while maintaining the quality of the fiber and seed. 展开更多
关键词 Cotton Saw Gin Roll Box Seed Roll Productivity Rotation Frequency Critical Frequency Resonance Stiffness Mass Total Effective Mass SolidWorks Simulation
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基于LDA主题的改进TFIDF 95598工单智能分类研究 认领
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作者 武光华 李洪宇 +2 位作者 刘二刚 柳长发 李倩 《微型电脑应用》 2020年第3期87-90,共4页
为了提高95595工单智能分类的准确率,提出了基于LDA(Latent Dirichlet Allocation)的改进TFIDF算法。先对文本提取特征词,然后采用K-means算法进行聚类处理。构建LDA模型,获得概率分布函数θ和φ,求取语义影响力SI(semantic influence,... 为了提高95595工单智能分类的准确率,提出了基于LDA(Latent Dirichlet Allocation)的改进TFIDF算法。先对文本提取特征词,然后采用K-means算法进行聚类处理。构建LDA模型,获得概率分布函数θ和φ,求取语义影响力SI(semantic influence,SI)作为特征词的权重,该改进算法记作SI-TFIDF(semantic influence-term frequency inverse document frequency,SI-TFIDF)。将SI-TFIDF算法与传统的TFIDF算法在sougou的数据库进行特征词提取,并采用K-means算进行聚类,对比结果显示,采用SI-TFIDF算法提取的特征词聚类效果优于TFIDF,验证了所提出方法的可靠性。在95598投诉工单上进行仿真实验,SI-TFIDF算法的投诉工单聚类准确率高于传统的TFIDF算法,验证了SI-TFIDF更适用于处理工单投诉的分类研究。 展开更多
关键词 95598 投诉工单 LATENT DIRICHLET ALLOCATION TERM FREQUENCY inverse document FREQUENCY
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遗传学定律教学中概率与频率的辨析问题 认领
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作者 卫红萍 任衍钢 +1 位作者 白冠军 路彦文 《黔南民族师范学院学报》 2020年第4期113-115,共3页
遗传学中的三大定律和哈代—温伯格定律是中学生物课的重点和难点内容,它们都是建立在数理统计基础上的推论。分离定律和自由组合定律是应用概率事件进行推论,连锁和交换定律以及哈代-温伯格定律是用频率现象进行推论。教学中要注意辨... 遗传学中的三大定律和哈代—温伯格定律是中学生物课的重点和难点内容,它们都是建立在数理统计基础上的推论。分离定律和自由组合定律是应用概率事件进行推论,连锁和交换定律以及哈代-温伯格定律是用频率现象进行推论。教学中要注意辨析这些术语的差异。 展开更多
关键词 遗传学定律 概率 频率 观测频率 期望频率
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Progress on the^40Ca^+ion optical clock 认领
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作者 张宝林 黄垚 +4 位作者 张华青 郝艳梅 曾孟彦 管桦 高克林 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第7期69-76,共8页
Progress of the ^40Ca^+ion optical clock based on the 4^2S1/2-3d ^2D5/2 electric quadrupole transition is reported.By setting the drive frequency to the“magic”frequencyΩ0,the frequency uncertainty caused by the scal... Progress of the ^40Ca^+ion optical clock based on the 4^2S1/2-3d ^2D5/2 electric quadrupole transition is reported.By setting the drive frequency to the“magic”frequencyΩ0,the frequency uncertainty caused by the scalar Stark shift and second-order Doppler shift induced by micromotion is reduced to the 10^-19 level.By precisely measuring the differential static scalar polarizability∆α0,the uncertainty due to the blackbody radiation(BBR)shift(coefficient)is reduced to the 10^-19 level.With the help of a second-order integrating servo algorithm,the uncertainty due to the servo error is reduced to the 10^-18 level.The total fractional uncertainty of the ^40Ca^+ion optical clock is then improved to 2.2×10^-17,whereas this value is mainly restricted by the uncertainty of the BBR shift due to temperature fluctuations.The state preparation is introduced together with improvements in the pulse sequence,and furthermore,a better signal to noise ratio(SNR)and less dead time are achieved.The clock stability of a single clock is improved to 4.8×10^-15√τ(in seconds). 展开更多
关键词 ^40Ca^+ion optical clocks “magic”drive frequency frequency uncertainty frequency stability
文章速递A.C. Recombination Velocity as Applied to Determine n<sup>+</sup>/p/p<sup>+</sup>Silicon Solar Cell Base Optimum Thickness 认领
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作者 Amadou Mar Ndiaye Sega Gueye +6 位作者 Ousmane Sow Gora Diop Amadou Mamour Ba Mamadou Lamine Ba Ibrahima Diatta Lemrabott Habiboullah Gregoire Sissoko 《能源与动力工程(英文)》 2020年第10期543-554,共12页
This work deals with determining the optimum thickness of the base of an n<sup>+</sup>/p/p<sup>+</sup> silicon solar cell under monochromatic illumination in frequency modulation. The continuit... This work deals with determining the optimum thickness of the base of an n<sup>+</sup>/p/p<sup>+</sup> silicon solar cell under monochromatic illumination in frequency modulation. The continuity equation for the density of minority carriers generated in the base, by a monochromatic wavelength illumination (<i>λ</i>), with boundary conditions that impose recombination velocities (<i>Sf</i>) and (<i>Sb</i>) respectively at the junction and back surface, is resolved. The ac photocurrent is deduced and studied according to the recombination velocity at the junction, to extract the mathematical expressions of recombination velocity (<i>Sb</i>). By the graphic technique of comparing the two expressions obtained, depending on the thickness (<i>H</i>) of the base, for each frequency, the optimum thickness (Hopt) is obtained. It is then modeled according to the frequency, at the long wavelengths of the incident light. Thus, Hopt decreases due to the low relaxation time of minority carriers, when the frequency of modulation of incident light increases. 展开更多
关键词 Silicon Solar Cell Modulation Frequency Recombination Velocity Base Thickness Wavelength
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文章速递Relationship between Breakfast and Academic Performance of Primary and Middle School Students in Mianyang City 认领
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作者 Xiao Chen Hongyu Chen +3 位作者 Linquan Gong Yonggen Fang Xiaobing Luo Dianqing Zhu 《健康(英文)》 2020年第10期1383-1389,共7页
In order to understand the relationship between breakfast frequency and academic performance of grade 5 and grade 8 students, we conducted an investigation through a multistage cluster sampling design with 16,840 stud... In order to understand the relationship between breakfast frequency and academic performance of grade 5 and grade 8 students, we conducted an investigation through a multistage cluster sampling design with 16,840 students (8017 5th graders and 8823 8th graders) from Mianyang city. Results show that: 1) 71.3% of fifth graders and 59.7% of eighth graders had breakfast every day of the week, and 9.7% of fifth graders and 7.5% of eighth graders had breakfast three times or less per week. 2) The number of times students eat breakfast per week has a significant impact on their comprehensive academic performance, which is reflected in the trend that the more times students eat breakfast, the better their overall academic performance is. Based on this, in order to help students eat breakfast more often, and further improve students’ academic performance, we will strengthen the publicity and education of students’ breakfast knowledge from multiple perspectives. 展开更多
关键词 Breakfast Frequency Academic Performance Students Mianyang City
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文章速递Maternal-Fetal Prognosis of the Prophylactic Cesaarian versus Emergency Cesaarian at the Reference Health Center of Commune V of Bamako District, Mali 认领
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作者 Cheickna Sylla Soumano Oumar Traoré +11 位作者 Alassane Traoré Alou Samaké Saleck Doumbia Saoudatou Tall Belco Tamboura Sitapha Dembélé Seydou Z. Dao Ibrahima Teguété Youssouf Traoré Niani Mounkoro Mamadou Traoré Amadou Ingré Dolo 《外科学(英文)》 2020年第10期329-341,共13页
<strong>Objectives:</strong> The goal was to assess the risk factors for emergency cesarean section versus prophylactic caesarean section. <strong>Materials and Methods:</strong> This was a des... <strong>Objectives:</strong> The goal was to assess the risk factors for emergency cesarean section versus prophylactic caesarean section. <strong>Materials and Methods:</strong> This was a descriptive analytical cross-sectional study of the Type Cas/Witnesses at the Reference Health Centre of Commune V of the District of Bamako in Mali. The sample consisted of 100 cases for 200 controls (1 case for 2 controls) with retrospective collection of data for the period from January 1 to July 11, 2011 (6 months and 11 days). <strong>Results:</strong> During the study period, out of a total of 3559 deliveries, we recorded 2,794 vaginal deliveries, 78.50% and 765 caesarean sections or 21.50%. Of the 765ceras, we performed 353 emergency caesarean sections or 46.15% and 412 prophylactic caesarean sections 53.85%. We have selected 100 prophylactic caesarean section files and 200 emergency caesarean section files. The average age of the patients was 27.41 years-5.84 with extreme ages of 14 to 40 years. 100% of our patients (Cas) had performed at least one antenatal consultation compared to 83.5% of the parturients evacuated (Witnesses). The most frequently cited reasons for evacuation were: acute fetal suffering, non-cephalic presentation and excessive uterine height with 30%, 17.5% and 12% respectively. The bulk of the caesarean section indications were dominated by dystocies with 90% in cases compared to 65% in Witnesses, followed by acute fetal suffering with 30% in Witnesses. We recorded 30% perinatal deaths among Witnesses compared to 1% in Cases. We recorded 16 uterine ruptures in the Witnesses among which 2 hysterectomies and 14 hystererraphia. <strong>Conclusion:</strong> Prophylactic caesarean section improves maternal and perinatal prognosis more than emergency caesarean section. 展开更多
关键词 Caesarean Frequency Evacuation Maternal-Fetal Prognosis
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文章速递Diffusion Coefficient at Resonance Frequency as Applied to n+/p/p+ Silicon Solar Cell Optimum Base Thickness Determination 认领
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作者 Amadou Mar Ndiaye Sega Gueye +6 位作者 Mame Faty Mbaye Fall Gora Diop Amadou Mamour Ba Mamadou Lamine Ba Ibrahima Diatta Lemrabott Habiboullah Gregoire Sissoko 《电磁分析与应用期刊(英文)》 2020年第10期145-158,共14页
The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial developm... The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial development for a low cost. In this work, an n+/p/p+ crystalline silicon solar cell is studied under monochromatic illumination in modulation and placed in a constant magnetic field. The minority carriers’ diffusion coefficient (<em>D</em>(<em>ω</em>, <em>B</em>), in the (<em>p</em>) base leads to maximum values (Dmax) at resonance frequencies (<em>ωr</em>). These values are used in expressions of AC minority carriers recombination velocity (Sb(Dmax, H)) in the rear of the base, to extract the optimum thickness while solar cell is subjected to these specific conditions. Optimum thickness modelling relationships, depending respectively on Dmax, <em>ωr</em> and <em>B</em>, are then established, and will be data for industrial development of low-cost solar cells for specific use. 展开更多
关键词 Silicon Solar Cell Resonance Frequency Magnetic Field Recombination Velocity Base Thickness
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文章速递A New Theory on Electron Wave-Particle Duality 认领
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作者 Nader Butto 《高能物理(英文)》 2020年第4期567-578,共12页
A theory employing the vortex shape of the electron was presented to resolve the enigma of the wave-particle duality. Conventions such as “particle” and “wave” were used to describe the behavior of quantum objects... A theory employing the vortex shape of the electron was presented to resolve the enigma of the wave-particle duality. Conventions such as “particle” and “wave” were used to describe the behavior of quantum objects such as electrons. A superfluid vacuum formed the base to describe the basic vortex structure and properties of the electron, whereas various formulations derived from hydrodynamic laws described the electron vortex circumference, radius, angular velocity and angular frequency, angular momentum (spin) and magnetic momentum. A vortex electron fully explained the associations between momentum and wave, and hydrodynamic laws were essential in deriving the energy and angular frequency of the electron. In general, an electron traveling in space possesses internal and external motions. To derive the angular frequency of its internal motion, the Compton wavelength was used to represent the length of one cycle of the internal motion that is equal to the circumference of the electron vortex. The angular frequency of the electron vortex was calculated to obtain the same value according to Planck’s theory. A traveling vortex electron has internal and external motions that create a three-dimensional helix trajectory. The magnitude of the instantaneous velocity of the electron is the resultant of its internal and external velocities, being equal to the internal velocity reduced by the Lorentz factor (whose essence is presented in a detailed formulation). The wavelength of the helix trajectory represents the distance traveled by a particle along its axis during one period of revolution around the axis, resulting in the same de Broglie wavelength that corresponds to the helix pitch of the helix. Mathematical formulations were presented to demonstrate the relation between the energy of the vortex and its angular frequency and de Broglie’s wavelength;furthermore, Compton’s and de Broglie’s wavelengths were also differentiated. 展开更多
关键词 Superfluid Vortex Compton Wavelength Electron Momentum Broglie Wavelength Lorentz Factor Angular Frequency
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Frequency Control of Power System with Renewable Power Sources by HVDC Interconnection Line and Battery Considering Energy Balancing 认领
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作者 Shoyu Onuka Atsushi Umemura +4 位作者 Rion Takahashi Junji Tamura Atsushi Sakahara Fumihito Tosaka Ryosuke Nakamoto 《电力能源(英文)》 2020年第4期11-24,共14页
Recently, introduction of renewable energy sources like wind power generation and photovoltaic power generation has been increasing from the viewpoint of environmental problems. However, renewable energy power supplie... Recently, introduction of renewable energy sources like wind power generation and photovoltaic power generation has been increasing from the viewpoint of environmental problems. However, renewable energy power supplies have unstable output due to the influence of weather conditions such as wind speed variations, which may cause fluctuations of voltage and frequency in the power system. This paper proposes fuzzy PD based virtual inertia control system to decrease frequency fluctuations in power system caused by fluctuating output of renewable energy sources. The proposed new method is based on the coordinated control of HVDC interconnection line and battery, and energy balancing control is also incorporated in it. Finally, it is concluded that the proposed system is very effective for suppressing the frequency fluctuations of the power system due to the large-scale wind power generation and solar power generation and also for keeping the energy balancing in the HVDC transmission line. 展开更多
关键词 High Voltage Direct Current (HVDC) Transmission POWER System Frequency CONTROL COORDINATED CONTROL BATTERY RENEWABLE POWER Energy Balancing
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地震分频AVO技术在孟加拉湾海域深水沉积储层烃类检测中的应用 认领
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作者 左国平 范国章 +5 位作者 蔡铮 郭渊 丁梁波 马宏霞 孙辉 王雪峰 《天然气地球科学》 EI CAS CSCD 北大核心 2020年第4期567-577,共11页
直接利用叠前地震资料进行烃类检测在海洋深水油气勘探中具有重要作用。传统的AVO方法在烃类检测中应用广泛,但在薄层、高孔隙度含水砂岩、低含气饱和度等情况下存在多解性和不确定性。实际上,地震波在油气储层中传播会产生较强的频散... 直接利用叠前地震资料进行烃类检测在海洋深水油气勘探中具有重要作用。传统的AVO方法在烃类检测中应用广泛,但在薄层、高孔隙度含水砂岩、低含气饱和度等情况下存在多解性和不确定性。实际上,地震波在油气储层中传播会产生较强的频散和能量衰减,这种变化在叠前地震资料振幅和频率上均存在响应。因此把分频技术与AVO技术结合起来是解决烃类检测多解性的有效方法之一。针对传统AVO方法和分频技术进行烃类检测存在不足,通过模型正演、AVO技术和分频技术以及它们的有效结合应用,集成了地震分频AVO烃类检测方法,在孟加拉湾海域深水沉积储层烃类检测中取得了良好的应用效果,验证了该方法在海洋深水沉积储层烃类检测的可行性及有效性,进一步提高了储层烃类检测的可靠性,有效地降低了烃类检测的多解性。 展开更多
关键词 振幅 频率 烃类检测 正演 AVO 分频 深水沉积储层
Directional Filter, Local Frequency Estimate and Algebraic Inversion of Differential Equation of Psoas Major Magnetic Resonance Elastography 认领
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作者 Surendra Maharjan Tomokazu Numano +4 位作者 Tetsushi Habe Daiki Ito Takamichi Ueki Keisuke Igarashi Toshiki Maeno 《医学影像期刊(英文)》 2020年第1期1-16,共16页
Magnetic resonance elastography (MRE) can visualize the shear wave propagation of in vivo tissues, which can be mapped into viscoelastic properties. No study has measured the biomechanical properties of the PM muscle ... Magnetic resonance elastography (MRE) can visualize the shear wave propagation of in vivo tissues, which can be mapped into viscoelastic properties. No study has measured the biomechanical properties of the PM muscle in vivo using MRE. In this study, we evaluated stiffness values calculated by local frequency estimate (LFE) and algebraic inversion of differential equation (AIDE) in PM-MRE. The PM muscles of 17 healthy male volunteers were scanned in supine position by MRE. The Laplacian-based estimate (LBE) phase wrapped image data were filtered by gaussian-bandpass filter (GBF), and by both directional and GBF. LFE (MREWave) and AIDE wave inversion methods were used to calculate the respective elastograms. The wave interferences were removed by directional filtering, and smooth wave fields were obtained. The stiffness values calculated by LFE of non-DF images were 1.39 ± 0.25 kPa and 1.33 ± 0.22 kPa for right and left PM respectively, whereas for DF images, they were 1.26 ± 0.20 kPa for right PM and 1.18 ± 0.28 kPa for left PM. The stiffness values calculated by AIDE of non-DF images were 0.78 ± 0.10 kPa and 0.78 ± 0.13 kPa for right and left PM respectively, whereas for DF images, they were 0.73 ± 0.12 kPa for right PM and 0.74 ± 0.11 kPa for left PM. There was no statistically significant difference in mean values of stiffness with/without applying directional filter whereas there was a statistically significant difference in mean values of stiffness between LFE and AIDE. Both LFE and AIDE could be used for psoas major MR Elastography. 展开更多
关键词 Magnetic Resonance Elastography MRE PSOAS MAJOR Muscle LOCAL Frequency Estimate LFE ALGEBRAIC INVERSION of Differential Equation AIDE
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Beamforming analysis based on CSB sin-FDA 认领
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作者 WANG Bo XIE Junwei +1 位作者 ZHANG Jing ZHANG Haowei 《系统工程与电子技术:英文版》 SCIE EI CSCD 2020年第1期73-84,共12页
This paper studies the adaptive beamforming algorithm based on the frequency diverse array(FDA)array where the interference is located at the same angle(but different range)with the target.We take the cross subarray-b... This paper studies the adaptive beamforming algorithm based on the frequency diverse array(FDA)array where the interference is located at the same angle(but different range)with the target.We take the cross subarray-based FDA with sinusoidal frequency offset(CSB sin-FDA)as the receiving array instead of the basic FDA.The sampling covariance matrix under insufficient snapshot can be corrected by the automatic diagonal loading method.On the basis of decomposing the mismatched steering vector error into a vertical component and a parallel one,this paper searches the vertical component of the error by the quadratic constraint method.The numerical simulation verifies that the beamformer based on the CSB sin-FDA can effectively hold the mainlobe at the target position when the snapshot is insufficient or the steering vector is mismatched. 展开更多
关键词 receiving processing architectures minimum variance distortionless response(MVDR)beamformer cross subarraybased FREQUENCY diverse array with sinusoidal FREQUENCY offset(CSB sin-FDA) steering vector SNAPSHOTS
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考虑功率变化速率的储能辅助单机调频控制策略 认领
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作者 赵源筱 耿光超 +3 位作者 江全元 刘文龙 陈义宣 李玲芳 《电力自动化设备》 EI CSCD 北大核心 2020年第1期141-147,共7页
风电具有显著的波动性和不确定性,大规模风电并网给电力系统的频率调节带来了严峻的挑战。储能具有灵活爬坡特性和双向调节能力,可有效辅助常规机组参与频率调节,提高参与自动发电控制(AGC)的机组响应能力,从而提高高风电功率波动系统... 风电具有显著的波动性和不确定性,大规模风电并网给电力系统的频率调节带来了严峻的挑战。储能具有灵活爬坡特性和双向调节能力,可有效辅助常规机组参与频率调节,提高参与自动发电控制(AGC)的机组响应能力,从而提高高风电功率波动系统的频率稳定性。以机组功率调节速率能否弥补系统功率波动为判断依据,以储能的有功功率变化速率和有功功率基点作为控制变量,提出一种考虑功率变化速率的储能辅助单台火电AGC机组参与电力系统频率调节的协调控制策略,自适应决策储能的动作时机和动作速率。基于PSCAD/ETMDC平台的仿真结果表明,所提策略以储能更少的动作频度和动作深度,达到了更优的调频效果,可有效减少储能功率/能量容量配置,具有良好的经济性,为储能的多场景应用奠定了基础。 展开更多
关键词 风电并网 储能 火电机组 频率 自动发电控制 功率变化速率 辅助调频 协调控制
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Investigation of Quantum Entanglement through a Trapped Three Level Ion Accompanied with Beyond Lamb-Dicke Regime 认领
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作者 Rasim Dermez 《量子信息科学期刊(英文)》 2020年第2期23-35,共13页
In this study, our goal is to obtain the entanglement dynamics of trapped three-level ion interaction two laser beams in beyond Lamb-Dicke parameters. Three values of LDP, <span style="white-space:nowrap;"... In this study, our goal is to obtain the entanglement dynamics of trapped three-level ion interaction two laser beams in beyond Lamb-Dicke parameters. Three values of LDP, <span style="white-space:nowrap;"><em>η</em>=0.09, <span style="white-space:nowrap;"><em>η</em>=0.2 </span></span>and <span style="white-space:nowrap;"><em>η</em>=0.3 </span>are given. We used the concurrence and the negativity to measure the amount of quantum entanglement created in the system. The interacting trapped ion led to the formation of phonons as a result of the coupling. In two quantum systems (ion-phonons), analytical formulas describing both these measurements are constructed. These formulas and probability coefficients include first order terms of final state vector. We report that long survival time of entanglement can be provided with two quantum measures. Negativity and concurrence maximum values are obtained N = 0.553 and for LDP = 0.3. As a similar, the other two values of LDP are determined and taken into account throughout this paper. For a more detailed understanding of entanglement measurement results, “contour plot” was preferred in Mathematica 8. 展开更多
关键词 Entangled State Trapped Three-Level Ion Lamb-Dick Parameter Rabi Frequency Quantum Measures
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Frequency sensitivity of the passive third harmonic superconducting cavity for SSRF 认领
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作者 Xiao-Yun Pu Hong-Tao Hou +4 位作者 Yan Wang Zheng Li Jing Shi Yu-Bin Zhao Jian-Fei Liu 《核技术:英文版》 SCIE CAS CSCD 2020年第3期85-93,共9页
A 1.5 GHz passive third harmonic superconducting cavity was proposed to improve the beam quality and lifetime in the Shanghai Synchrotron Radiation Facility Phase-II beamline project.Lifetime improvement highly depend... A 1.5 GHz passive third harmonic superconducting cavity was proposed to improve the beam quality and lifetime in the Shanghai Synchrotron Radiation Facility Phase-II beamline project.Lifetime improvement highly depends on the resonant frequency of the passive third harmonic superconducting cavity.It is important that the operating frequency of the cavity is within the design range and the cavity has reasonable mechanical stability.A simulation method for the multiphysics coupled analysis has been developed based on the ANSYS code.Multiphysics coupled simulations have been performed under different conditions,such as etching,evacuation,cooling,and preloading.Analyses of mechanical modes and structural stress have been executed.A possible stiffening ring method for the two-cell superconducting niobium cavity has been investigated.In this paper,we present a multiphysics coupled analysis of the third harmonic cavity using a finite element analysis code.The results of the analysis show that a reliable frequency for the cavity after electron beam welding is 1498.033 MHz,and the corresponding frequency of the pre-tuning goal is 1496.163 MHz.A naked cavity is a reasonable option based on structural stress and mechanical modal analyses.A frequency range of±500 kHz and limiting tolerable displacement of±0.35 mm are proposed for the design of the frequency tuner. 展开更多
关键词 Superconducting CAVITY PASSIVE harmonic CAVITY FREQUENCY DETUNING FREQUENCY TUNER MULTIPHYSICS analysis
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Design and Simulation of Improved SOI SiGe Hetero-Junction Bipolar Transistor Architecture with Strain Engineering 认领
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作者 Naidan Miao Peipei Liu +6 位作者 Jianhao Wen Jinxi Wei Baichuan Zhang Shiqi Wang Ruwen Zeng Guanyu Wang Chunyu Zhou 《应用数学与应用物理(英文)》 2020年第2期218-228,共11页
In order to improve the electrical and frequency characteristics of SiGe heterojunction bipolar transistors (HBTs), a novel structure of SOI SiGe heterojunction bipolar transistor is designed in this work. Compared wi... In order to improve the electrical and frequency characteristics of SiGe heterojunction bipolar transistors (HBTs), a novel structure of SOI SiGe heterojunction bipolar transistor is designed in this work. Compared with traditional SOI SiGe HBT, the proposed device structure has smaller window widths of emitter and collector areas. Under the act of additional uniaxial stress induced by Si0.85Ge0.15, all the collector region, base region and emitter region are strained, which is beneficial to improve the performance of SiGe HBTs. Employing the SILVACO&#9415;TCAD tools, the numerical simulation results show that the maximum current gain βmax, the Earley voltage VA are achieved for 1062 and 186 V, respectively, the product of β and VA, i.e., β ×VA, is 1.975 × 105 V and, the peak cutoff frequency fT is 419 GHz when the Ge component in the base has configured to be a trapezoidal distribution. The proposed SOI SiGe HBT architecture has a 52.9% improvement in cutoff frequency fT compared to the conventional SOI SiGe HBTs. 展开更多
关键词 UNIAXIAL STRAIN SOI SIGE HBT Electrical PERFORMANCE Frequency PERFORMANCE
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Quantum Coherent Entangled Hydrogen Atom Non-Locality 认领
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作者 Mark Moody 《应用数学与应用物理(英文)》 2020年第5期737-752,共16页
The discovery of a data based informational wave pattern infuses coherent entanglement into the system. This discovery of how to add coherent entanglement into the model provides the missing key, that has opened the d... The discovery of a data based informational wave pattern infuses coherent entanglement into the system. This discovery of how to add coherent entanglement into the model provides the missing key, that has opened the door to understanding the universe. It is found that the inclusion of coherence and entanglement at the start of the system is extremely simple and in fact it is so simple that it has simply been overlooked. Entanglement and coherence are the most fundamental aspects of our universe. It is demonstrated that the basic model of the hydrogen atom is made from the CMB. If we add entanglement into this basic model of the hydrogen atom a math system called Wave Pattern Entangled Math is unveiled. This system of wave interference mathematics creates a data system in which entanglement and coherence can easily be understood. The final outcome is an unbreakable pattern of information, including entangled energy, entropy, spin, universal expansion, compression, velocity of light, C2, and Quantum Coherence. 展开更多
关键词 Entropy Function Entanglement ENTANGLED Universal Matrix WAVE Pattern ENTANGLED MATH WPEM Complementarity CAUSALITY Wave-Particle Duality Hydrogen Atom C.M.B. Cosmic Microwave Background WAVE Frequency
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非均匀船舶尾流中工作的常规和大侧斜船用螺旋桨的水动力和水声计算预报 认领
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作者 S.E.Belhenniche O.Imine O.K.Kinaci 《船舶与海洋工程学报:英文版》 CSCD 2020年第1期28-40,共13页
Despite their high manufacturing cost and structural deficiencies especially in tip regions,highly skewed propellers are preferred in the marine industry,where underwater noise is a significant design criterion.Howeve... Despite their high manufacturing cost and structural deficiencies especially in tip regions,highly skewed propellers are preferred in the marine industry,where underwater noise is a significant design criterion.However,hydrodynamic performances should also be considered before a decision to use these propellers is made.This study investigates the trade-off between hydrodynamic and hydroacoustic performances by comparing conventional and highly skewed Seiun Maru marine propellers for a noncavitating case.Many papers in the literature focus solely on hydroacoustic calculations for the open-water case.However,propulsive characteristics are significantly different when propeller-hull interactions take place.Changes in propulsion performance also reflect on the hydroacoustic performances of the propeller.In this study,propeller-hull interactions were considered to calculate the noise spectra.Rather than solving the full case,which is computationally demanding,an indirect approach was adopted;axial velocities from the nominal ship wake were introduced as the inlet condition of the numerical approach.A hybrid method based on the acoustic analogy was used in coupling computational fluid dynamics techniques with acoustic propagation methods,implementing the Ffowcs Williams-Hawkings(FW-H)equation.The hydrodynamic performances of both propellers were presented as a preliminary study.Propeller-hull interactions were included in calculations after observing good accordance between our results,experiments,and quasi-continuous method for the open-water case.With the use of the time-dependent flow field data of the propeller behind a nonuniform ship wake as an input,simulation results were used to solve the FW-H equation to extract acoustic pressure and sound pressure levels for several hydrophones located in the near field.Noise spectra results confirm that the highest values of the sound pressure levels are in the low-frequency range and the first harmonics calculated by the present method are in good accordance with the theor 展开更多
关键词 Seiun Maru Moving reference frame Underwater acoustics Underwater noise Sound pressure level Blade passing frequency FW-H equation HYDROPHONES
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Study at Two Dimensions of Thermal Transfer through a Fibers Panel Subjected to Climatic Constraints in Dynamic Frequency Regulations Established 认领
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作者 Mohamed Sidya Ould Brahim Issa Diagne +7 位作者 Mamadou Babacar Ndiaye Youssou Traore Seydou Faye Cheikh Thiam Pape Touty Traore Ablaye Fame Sokhna Khadidiatou Ben Thiam Gregoire Sissoko 《能源与动力工程(英文)》 2020年第5期135-142,共8页
From resolution of two-dimensional equation of heat in dynamic frequency regime, we have plotted evolution curves of temperature according to depth of material or in lateral direction. They will allow us to evaluate t... From resolution of two-dimensional equation of heat in dynamic frequency regime, we have plotted evolution curves of temperature according to depth of material or in lateral direction. They will allow us to evaluate thermal behavior of towed material. Aim of study is to use fibers as a thermal insulating material by proposing a method for determining effective thermal insulation layer in dynamic frequency regime. 展开更多
关键词 Thermal Transfer Heat Exchange COEFFICIENT Frequency Dynamic REGIME Fibers
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