期刊文献+
共找到564篇文章
< 1 2 29 >
每页显示 20 50 100
Bursting oscillation in CO oxidation with small excitation and the enveloping slow-fast analysis method 被引量:2
1
作者 李向红 毕勤胜 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第6期100-106,共7页
Based on the traditional scheme for a nonlinear system with multiple time scales, the enveloping slow-fast analysis method is developed in the paper, which can be employed to investigate the dynamics of nonlinear fiel... Based on the traditional scheme for a nonlinear system with multiple time scales, the enveloping slow-fast analysis method is developed in the paper, which can be employed to investigate the dynamics of nonlinear fields with multiple time scales with periodic excitation. Upon using the method, the behaviors of the kinetic model of CO oxidation on the platinum group metals have been explored in detail. Two typicM bursting phenomena such as Fold/Fold/Hopf bursting and Fold/Fold bursting, are presented, the bifurcation mechanisms of which have been obtained. Furthermore, the dynamic difference between the two cases corresponding to relatively large and small perturbation frequencies, respectively, has been presented, which can be used to describe the influence of the frequencies involving in the evolution on the bursting behaviors in the system. 展开更多
关键词 CO oxidation bursting phenomenon bifurcation mechanism enveloping slow-fast anal-ysis
下载PDF
Temperature Field Simulation and Experimental Study of Anti‑backlash Single‑Roller Enveloping Hourglass Worm Gear 被引量:2
2
作者 Shisong Wang Shike Wang +1 位作者 Jie Wang Xingqiao Deng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2020年第4期77-86,共10页
In gear transmission,temperature rise has a non-negligible impact on the accuracy,noise and transmission efficiency.However,there is no relevant research on the temperature rise of the anti-backlash single-roller enve... In gear transmission,temperature rise has a non-negligible impact on the accuracy,noise and transmission efficiency.However,there is no relevant research on the temperature rise of the anti-backlash single-roller enveloping hourglass worm(ASEHW)gear.To solve this problem,based on tribology principle and Hertz contact theory,the thermal power calculation method of the ASEHW gear was proposed for the first time and thermal analysis was carried out by Ansys software.The bulk temperature of the ASEHW gear under four different rotating speed(300 r/min,600 r/min,900 r/min,1200 r/min)is calculated.The main factors causing temperature rise of the ASEHW gear are analyzed theoretically.Meanwhile,an experimental study is performed to verify the simulation results and validate the theory methods.The theory presented in this paper provides a solution for the thermal power calculation of ASEHW gear.This research provides a theoretical basis for further optimization of ASEHW gear. 展开更多
关键词 Roller enveloping hourglass worm gear Finite element analysis Temperature field
下载PDF
Extensions of quantum enveloping algebras 被引量:2
3
作者 HONG Yan-yong WU Zhi-xiang 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2012年第3期290-304,共15页
In this paper, we define a class of extended quantum enveloping algebras Uq (f(K, J)) and some new Hopf algebras, which are certain extensions of quantum enveloping algebras by a Hopf algebra H. This construction ... In this paper, we define a class of extended quantum enveloping algebras Uq (f(K, J)) and some new Hopf algebras, which are certain extensions of quantum enveloping algebras by a Hopf algebra H. This construction generalizes some well-known extensions of quantum enveloping algebras by a Hopf algebra and provides a large of new noncommutative and nonco- commutative Hopf algebras. 展开更多
关键词 quantum enveloping algebra Kac-Moody algebra ambiskew polynomial ring.
下载PDF
Experiment on low-frequency electromagnetic waves propagating in shock-tube-generated magnetized cylindrical enveloping plasma
4
作者 郭韶帅 谢楷 +2 位作者 孙斌 席若尧 刘艳 《Plasma Science and Technology》 SCIE EI CAS CSCD 2021年第7期67-77,共11页
We propose a method of applying a static magnetic field to reduce the attenuation of the magnetic field component(SH) of low-frequency electromagnetic(LF EM) waves in dense plasma. The principle of this method is to a... We propose a method of applying a static magnetic field to reduce the attenuation of the magnetic field component(SH) of low-frequency electromagnetic(LF EM) waves in dense plasma. The principle of this method is to apply a static magnetic field to limit electron movement, thereby increasing the equivalent resistance and thus reducing the induced current and SH. We consider the static magnetic field acting on the plasma of the entire induced current loop rather than on the local plasma, where the induced current is excited by the magnetic field component of LF EM waves. Analytical expressions of SH suitable for magnetized cylindrical enveloping plasma are derived by adopting an equivalent circuit approach, by which SHis calculated with respect to various plasma parameter settings. The results show that SH can be reduced under a static magnetic field and the maximum magnetic field strength that mitigates blackout is less than 0.1 T. Experiments in which LF EM waves propagate in a shock-tubegenerated magnetized cylindrical enveloping plasma are also conducted. SH measured under the magnetic field(the magnetic field strength B0 acting on the magnetic field probe was about0.06 T) reduces at f=10 MHz and f=30 MHz when ne≈1.9×1013 cm-3, which is consistent with theoretical results. The verification of the theory thus suggests that applying a static magnetic field with a weak magnetic field has the potential to improve the transmission capacity of LF EM waves in dense plasma. 展开更多
关键词 static magnetic field shock tube low-frequency electromagnetic waves cylindrical enveloping plasma
下载PDF
Enveloping Lie Algebras of Low Dimensional Leibniz Algebras
5
作者 Massoud Amini Isamiddin Rakhimov Seyed Jalal Langari 《Applied Mathematics》 2011年第8期1027-1030,共4页
We calculate the enveloping Lie algebras of Leibniz algebras of dimensions two and three. We show how these Lie algebras could be used to distinguish non-isomorphic (nilpotent) Leibniz algebras of low dimension in som... We calculate the enveloping Lie algebras of Leibniz algebras of dimensions two and three. We show how these Lie algebras could be used to distinguish non-isomorphic (nilpotent) Leibniz algebras of low dimension in some cases. These results could be used to associate geometric objects (loop spaces) to low dimensional Leibniz algebras. 展开更多
关键词 LEIBNIZ ALGEBRA enveloping LIE ALGEBRA NILPOTENT ALGEBRA
下载PDF
ENVELOPING THEORY BASED METHOD FOR THE DETERMINATION OF PATH INTERVAL AND TOOL PATH OPTIMIZATION FOR SURFACE MACHINING
6
作者 Zhou Ji Zhou Yanhong Zhan Yong School of Mechanical Science & Engineering, Huazhong University of Science & Technology 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1999年第2期33-38,共6页
An enveloping theory based method for the determination of path interval in three axis NC machining of free form surface is presented, and a practical algorithm and the measures for improving the calculating efficien... An enveloping theory based method for the determination of path interval in three axis NC machining of free form surface is presented, and a practical algorithm and the measures for improving the calculating efficiency of the algorithm are given. Not only the given algorithm can be used for ball end cutter, flat end cutter, torus cutter and drum cutter, but also the proposed method can be extended to arbitrary milling cutters. Thus, the problem how to strictly calculate path interval in the occasion of three axis NC machining of free form surfaces with non ball end cutters has been resolved effectively. On this basis, the factors that affect path interval are analyzed, and the methods for optimizing tool path are explored. 展开更多
关键词 Three axis Surface machining Path interval enveloping theory Tool path optimization
全文增补中
EXPERIMENTAL STUDY ON LUBRICATION BEHAVIOR OF DOUBLE ENVELOPING HOUK GLASSWOKM GEARING
7
作者 He Huinong,Zhou Yinsheng,Quan Yongxin,( Zhejiang, University) Wei Yunlong, Cao Xingjin, (Chongqing, University) 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1996年第1期57-62,共3页
The lubrication behavior of double enveloping hourglass worm gearing is studied experimently. The effects of rotational speed of the worm and load on the formation of the fluid film between engagement tooth ... The lubrication behavior of double enveloping hourglass worm gearing is studied experimently. The effects of rotational speed of the worm and load on the formation of the fluid film between engagement tooth surfaces are investigated in detail. and working angle of this worm gearing is also analyzed. Some beneficial results are obtained。 展开更多
关键词 Double enveloping hourglass worm gearing Lubrication mechanism Working angle Tooth root strain
全文增补中
The CCAAT/Enhancer Binding Protein Beta(cebpb)is essential for the development of enveloping layer(EVL)in zebrafish
8
作者 Xin Zhang Zhichao Wu +4 位作者 Mengdi Bu Ruiqin Hu Xiaowen Zhang Wenhao Li Liangbiao Chen 《Aquaculture and Fisheries》 CSCD 2023年第3期252-260,共9页
Epiboly,the coordinated spreading of the enveloping layer(EVL),the yolk syncytial layer(YSL)and the deep cells(DCs)toward the vegetal pole,is required for gastrulation.Interference with the EVL leads to early developm... Epiboly,the coordinated spreading of the enveloping layer(EVL),the yolk syncytial layer(YSL)and the deep cells(DCs)toward the vegetal pole,is required for gastrulation.Interference with the EVL leads to early developmental failure.However,the genetic factors underlying EVL differentiation are so far unknown.By in-depth analyzing of single-cell sequencing data from 4 h post fertilization zebrafish embryos,we identified 105 genes(FDR<0.05)which showed highly specific EVL expression,among which the transcription factor cebpb and genes(krt18,cldne,cldnb,krt4,krt5)involved in cell-cell junction formation were exclusively expressed in EVL.To explore the role of cebpb in EVL differentiation,we knocked down its expression by morpholino-labeled antisense RNA.The morphant embryos showed disrupted EVL and developmental termination prior to epiboly.In accordance,expression of the EVL specific cell-adhesion molecule genes were significantly reduced.Thus,cebpb is the earliest EVL marker and essential for EVL differentiation in zebrafish.The elucidation of the specific EVL gene set provides us new insights into the molecular mechanisms underlying EVL differentiation. 展开更多
关键词 Cebpb Single-cell RNA sequencing ZEBRAFISH enveloping layer(EVL)
原文传递
Realizing Enveloping Algebras via Varieties of Modules 被引量:3
9
作者 Ming DING Jie XIAO Fan XU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2010年第1期29-48,共20页
By using the Ringel-Hall algebra approach, we investigate the structure of the Lie algebra L(A) generated by indecomposable constructible sets in the varieties of modules for any finite- dimensional C-algebra A. We ... By using the Ringel-Hall algebra approach, we investigate the structure of the Lie algebra L(A) generated by indecomposable constructible sets in the varieties of modules for any finite- dimensional C-algebra A. We obtain a geometric realization of the universal enveloping algebra R(A) of L(A), this generalizes the main result of Riedtmann. We also obtain Green's formula in a geometric form for any finite-dimensional C-algebra A and use it to give the comultiplication formula in R(A). 展开更多
关键词 Ringel-Hall algebra constructible set VARIETY universal enveloping algebra
原文传递
(Quasi-)Poisson Enveloping Algebras 被引量:2
10
作者 Yan Hong YANG Yuan YAO Yu YE 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2013年第1期105-118,共14页
We introduce the quasi-Poisson enveloping algebra and Poisson enveloping algebra for a non-commutative Poisson algebra. We prove that for a non-commutative Poisson algebra, the category of quasi-Poisson modules is equ... We introduce the quasi-Poisson enveloping algebra and Poisson enveloping algebra for a non-commutative Poisson algebra. We prove that for a non-commutative Poisson algebra, the category of quasi-Poisson modules is equivalent to the category of left modules over its quasi-Poisson enveloping algebra, and the category of Poisson modules is equivalent to the category of left modules over its Poisson enveloping algebra. 展开更多
关键词 Non-commutative Poisson algebra Poisson module Poisson enveloping algebra
原文传递
Extension of a quantized enveloping algebra by a Hopf algebra 被引量:1
11
作者 WU ZhiXiang Department of Mathematics,Zhejiang University,Hangzhou 310027,China 《Science China Mathematics》 SCIE 2010年第5期300-307,共8页
Suppose that H is a Hopf algebra,and g is a generalized Kac-Moody algebra with Cartan matrix A =(aij)I×I,where I is an index set and is equal to either {1,2,...,n} or the natural number set N.Let f,g be two mappi... Suppose that H is a Hopf algebra,and g is a generalized Kac-Moody algebra with Cartan matrix A =(aij)I×I,where I is an index set and is equal to either {1,2,...,n} or the natural number set N.Let f,g be two mappings from I to G(H),the set of group-like elements of H,such that the multiplication of elements in the set {f(i),g(i)|i ∈I} is commutative.Then we define a Hopf algebra Hgf Uq(g),where Uq(g) is the quantized enveloping algebra of g. 展开更多
关键词 QUANTUM enveloping ALGEBRA HOPF ALGEBRA KAC-MOODY ALGEBRA
原文传递
Trial application of the envelope method to the potential ambiguity problem
12
作者 Li-Yuan Hu Yu-Shou Song 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第1期73-80,共8页
The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering data.For a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and f... The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering data.For a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farside scattering components.By contrast,the envelope method can decompose the experimental data into two components with negative and positive deflection angles,respectively.Hence,a question arises as to whether the comparison between the calculated nearside(or farside)component and the derived positive-deflection-angle(or negative-deflection-angle)component can help analyze the potential ambiguity problem.In this study,we conducted a trial application of the envelope method to the potential ambiguity problem.The envelope method was improved by including uncertainties in the experimental data.The colliding systems of 16O+28Si at 215.2 MeV and 12C+12C at 1016 MeV were considered in the analyses.For each colliding system,the angular distribution experimental data were described nearly equally well by two potential sets,one of which is“surface transpar-ent”and the other is refractive.The calculated angular distributions were decomposed into nearside and farside scattering components.Using the improved envelope method,the experimental data were decomposed into the positive-deflection-angle and negative-deflection-angle components,which were then compared with the calculated nearside and farside components.The capability of the envelope method to analyze the potential ambiguities was also discussed. 展开更多
关键词 Elastic scattering Optical potential ambiguities Envelope method Nearside/farside decomposition
下载PDF
Three-Dimensional Sound Source Location Algorithm for Subsea Leakage Using Hydrophone
13
作者 LI Hao-jie CAI Bao-ping +6 位作者 YUAN Xiao-bing KONG Xiang-di LIU Yong-hong Javed Akbar KHAN CHU Zheng-de YANG Chao TANG An-bang 《China Ocean Engineering》 SCIE EI CSCD 2024年第2期326-337,共12页
Leakages from subsea oil and gas equipment cause substantial economic losses and damage to marine ecosystem,so it is essential to locate the source of the leak.However,due to the complexity and variability of the mari... Leakages from subsea oil and gas equipment cause substantial economic losses and damage to marine ecosystem,so it is essential to locate the source of the leak.However,due to the complexity and variability of the marine environment,the signals collected by hydrophone contain a variety of noises,which makes it challenging to extract useful signals for localization.To solve this problem,a hydrophone denoising algorithm is proposed based on variational modal decomposition(VMD)with grey wolf optimization.First,the average envelope entropy is used as the fitness function of the grey wolf optimizer to find the optimal solution for the parameters K andα.Afterward,the VMD algorithm decomposes the original signal parameters to obtain the intrinsic mode functions(IMFs).Subsequently,the number of interrelationships between each IMF and the original signal was calculated,the threshold value was set,and the noise signal was removed to calculate the time difference using the valid signal obtained by reconstruction.Finally,the arrival time difference is used to locate the origin of the leak.The localization accuracy of the method in finding leaks is investigated experimentally by constructing a simulated leak test rig,and the effectiveness and feasibility of the method are verified. 展开更多
关键词 grey wolf optimizer variational modal decomposition mean envelope entropy correlation coefficient time difference of arrival
下载PDF
q-DEFORMED BOSON REPRESENTATIONS OF UNIVERSAL ENVELOPING ALGEBRAS IN THE CASE WHERE q IS A ROOT OF UNITY
14
作者 孙昌璞 葛墨林 《Science China Mathematics》 SCIE 1992年第8期944-956,共13页
By further improving the method of q-deformed boson realization, the standard basis is built for the typical subalgebra chains. When q is a root of unity, the irreducible and indecomposable representations of quantum ... By further improving the method of q-deformed boson realization, the standard basis is built for the typical subalgebra chains. When q is a root of unity, the irreducible and indecomposable representations of quantum universal enveloping algebras (A<sub>l-1</sub>)q and (C<sub>l</sub>)q are constructed and their reduction structure and decompositions are analyzed. 展开更多
关键词 QUANTUM group QUANTUM universal enveloping algebra INDECOMPOSABLE representation SUBALGEBRA chain.
原文传递
Universal Enveloping Algebras of Simple Symplectic Anti-Jordan Triple Systems
15
作者 Marina Tvalavadze 《Algebra Colloquium》 SCIE CSCD 2015年第2期281-292,共12页
In this work we axe concerned with the universal associative envelope of a finite-dimensional simple symplectic anti-Jordan triple system (AJTS). We prove that if T is a triple system as above, then there exists an ... In this work we axe concerned with the universal associative envelope of a finite-dimensional simple symplectic anti-Jordan triple system (AJTS). We prove that if T is a triple system as above, then there exists an associative algebra U(T) and an injective homomorphism ε : T→ U(T), where U(T) is an AJTS under the triple product defined by (a, b, c) = abc- cba. Moreover, U(T) is a universal object with respect to such homomorphisms. We explicitly determine the PBW-basis of U(T), the center Z(U(T)) and the Gelfand-Kirillov dimension of U(T). 展开更多
关键词 anti-Jordan triple systems universal enveloping algebras central elements PBW-bases
原文传递
Evaluation of Energy Efficiency and Analysis of Influencing Factors of Company CW’s Manufacturing Workshops
16
作者 Pengju Zhang 《Journal of Electronic Research and Application》 2024年第2期18-26,共9页
In this work,the Slacks-Based Measure(SBM)model within Data Envelopment Analysis was employed to establish a set of indicators for evaluating the energy efficiency of manufacturing workshops.The energy efficiency of 1... In this work,the Slacks-Based Measure(SBM)model within Data Envelopment Analysis was employed to establish a set of indicators for evaluating the energy efficiency of manufacturing workshops.The energy efficiency of 12 Company CW’s manufacturing workshops from 2016 to 2022 was assessed.The findings indicated that aside from a few workshops operating at the production frontier,the rest exhibit significant fluctuations in energy efficiency and generally low energy efficiency.Subsequently,a combined GRA-Tobit analysis model was introduced to identify factors influencing the energy efficiency of Company CW’s manufacturing workshops.Regression analysis revealed that technological investments,employee quality,workshop production scale,investment in clean energy,and the level of pollution control all significantly impact the energy efficiency of Company CW’s manufacturing workshops.By evaluating the energy efficiency of Company CW’s manufacturing workshops and studying their influencing factors,this research aids company managers in understanding the energy efficiency of the manufacturing process.It optimizes the combination of various production elements,thereby offering effective guidance for improving the energy efficiency issues of the company’s manufacturing workshops,which can contribute to enhancing the corporation’s overall energy efficiency. 展开更多
关键词 Manufacturing workshop energy efficiency Energy efficiency evaluation Data Envelopment Analysis(DEA) GRA-Tobit model
下载PDF
基于三阶段数据包络分析模型的苏浙沪皖经济圈医院运行效率研究 被引量:4
17
作者 田浩国 高山 杨令 《中国卫生资源》 CSCD 北大核心 2023年第1期61-65,共5页
目的分析2019年苏浙沪皖经济圈内27个城市医院运行效率,为优化苏浙沪皖卫生资源配置和规划提供参考。方法选取苏浙沪皖27个城市医院指标数据,运用三阶段数据包络分析(data envelopment analysis,DEA)模型法,在控制环境变量和剔除随机效... 目的分析2019年苏浙沪皖经济圈内27个城市医院运行效率,为优化苏浙沪皖卫生资源配置和规划提供参考。方法选取苏浙沪皖27个城市医院指标数据,运用三阶段数据包络分析(data envelopment analysis,DEA)模型法,在控制环境变量和剔除随机效应后效率分析。结果苏浙沪皖经济圈医院综合技术效率、纯技术效率和规模效率均值分别为0.941、0.948和0.992。结论苏浙沪皖经济圈内医院运行效率有所差异,环境变量对医院运行效率影响较大,对外部的资源配置存在敏感性不同的差异,应统筹区域医疗资源,提高医院运行效率。 展开更多
关键词 苏浙沪皖Jiangsu ZHEJIANG Shanghai ANHUI 综合技术效率comprehensive technical efficiency 纯技术效率pure technical efficiency 规模效率scale efficiency 三阶段数据包络分析three-stage data envelopment analysis
下载PDF
Pepper mild mottle virus coat protein interacts with pepper chloroplast outer envelope membrane protein OMP24 to inhibit antiviral immunity in plants 被引量:3
18
作者 Kelei Han Hongying Zheng +11 位作者 Dankan Yan Huijie Zhou Zhaoxing Jia Yushan Zhai Jian Wu Yuwen Lu Guanwei Wu Shaofei Rao Jianping Chen Jiejun Peng Rende Qi Fei Yan 《Horticulture Research》 SCIE CSCD 2023年第5期16-28,共13页
Pepper mild mottle virus(PMMoV)is a devastating viral pathogen of pepper(Capsicum annuum)but it is unclear whether and how peppers protect against PMMoV infection.The expression of the chloroplast outer membrane prote... Pepper mild mottle virus(PMMoV)is a devastating viral pathogen of pepper(Capsicum annuum)but it is unclear whether and how peppers protect against PMMoV infection.The expression of the chloroplast outer membrane protein 24(OMP24)of C.annuum was upregulated under PMMoV infection and it interacted with PMMoV coat protein(CP).Silencing of OMP24 in either C.annuum or Nicotiana benthamiana facilitated PMMoV infection,whereas overexpression of N.benthamiana OMP24 in transgenic plants inhibited PMMoV infection.Both C.annuum OMP24(CaOMP24)and N.benthamiana OMP24(NbOMP24)localized to the chloroplast and have a moderately hydrophobic transmembrane domain that is necessary for their localization.Overexpression of CaOMP24 induced stromules,perinuclear chloroplast clustering,and accumulation of reactive oxygen species(ROS),the typical defense responses of chloroplasts transferring the retrograde signaling to the nucleus to regulate resistance genes.The expression of PR1 and PR2 was also upregulated significantly in plants overexpressing OMP24.Self-interaction of OMP24 was demonstrated and was required for OMP24-mediated plant defense.Interaction with PMMoV CP interfered with the self-interaction of OMP24 and impaired OMP24-induced stromules,perinuclear chloroplast clustering and ROS accumulation.The results demonstrate the defense function of OMP24 in pepper during viral infection and suggest a possible mechanism by which PMMoV CP modulates the plant defense to facilitate viral infection. 展开更多
关键词 outer IMMUNITY ENVELOPE
下载PDF
A Novel Compact Highly Isolated UWB MIMO Antenna with WLAN Notch 被引量:1
19
作者 Muhammad Awais Shahid Bashir +3 位作者 Awais Khan Muhammad Asif Nasim Ullah Hend I.Alkhammash 《Computers, Materials & Continua》 SCIE EI 2023年第4期669-681,共13页
This paper presents a compact Multiple Input Multiple Output(MIMO)antenna with WLAN band notch for Ultra-Wideband(UWB)applications.The antenna is designed on 0.8mmthick low-cost FR-4 substrate having a compact size of... This paper presents a compact Multiple Input Multiple Output(MIMO)antenna with WLAN band notch for Ultra-Wideband(UWB)applications.The antenna is designed on 0.8mmthick low-cost FR-4 substrate having a compact size of 22mm×30 mm.The proposed antenna comprises of two monopole patches on the top layer of substrate while having a shared ground on its bottom layer.The mutual coupling between adjacent patches has been reduced by using a novel stub with shared ground structure.The stub consists of complementary rectangular slots that disturb the surface current direction and thus result in reducing mutual coupling between two ports.A slot is etched in the radiating patch for WLAN band notch.The slot is used to suppress frequencies ranging from 5.1 to 5.9 GHz.The results show that the proposed antenna has a very good impedance bandwidth of|S11|<−10 dB within the frequency band from 3.1–14 GHz.A low mutual coupling of less than−23 dB is achieved within the entire UWB band.Furthermore,the antenna has a peak gain of 5.8 dB,low ECC<0.002 and high Diversity Gain(DG>9.98). 展开更多
关键词 Multiple input multiple output(MIMO) ultra-wide band(UWB) defected ground structure envelope correlation coefficient diversity gain
下载PDF
基于DEA方法的江苏省制造业上市企业创新绩效研究 被引量:1
20
作者 姚梦琪 《科技和产业》 2023年第11期23-28,共6页
基于道格拉斯生产函数,构建了企业创新绩效评价指标体系,运用DEA-CCR、DEA-BCC、DEA-Malmquist模型测算了2018—2020年169家江苏省制造业上市企业静态效率和动态效率。研究表明,江苏省制造业上市企业研发投入呈现逐年递增趋势,但创新绩... 基于道格拉斯生产函数,构建了企业创新绩效评价指标体系,运用DEA-CCR、DEA-BCC、DEA-Malmquist模型测算了2018—2020年169家江苏省制造业上市企业静态效率和动态效率。研究表明,江苏省制造业上市企业研发投入呈现逐年递增趋势,但创新绩效整体没有达到最优状态,主要是由于纯技术效率较低所致,需要提升资源配置效率;且受疫情影响创新绩效整体上经历了一个从增长到衰退的过程,相对来说企业技术进步率大于技术效率变化率。 展开更多
关键词 DEA(data envelopment analysis 数据包络分析) MALMQUIST 江苏省制造业 上市企业 创新绩效
下载PDF
上一页 1 2 29 下一页 到第
使用帮助 返回顶部