期刊文献+
共找到12,366篇文章
< 1 2 250 >
每页显示 20 50 100
Trial application of the envelope method to the potential ambiguity problem
1
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
A New Dynamic and Vertical Photovoltaic Integrated Building Envelope for High-Rise Glaze-Facade Buildings
2
作者 Wuwei Zou Yan Wang +3 位作者 Enze Tian Jiaze Wei Jinqing Peng Jinhan Mo 《Engineering》 SCIE EI CAS CSCD 2024年第8期194-203,共10页
Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,... Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,and solar energy harvesting for glazed facades.In this study,we addressed these conflicts by introducing a new dynamic and vertical photovoltaic integrated building envelope(dvPVBE)that offers extraordinary flexibility with weather-responsive slat angles and blind positions,superior architectural aesthetics,and notable energy-saving potential.Three hierarchical control strategies were proposed for different scenarios of the dvPVBE:power generation priority(PGP),natural daylight priority(NDP),and energy-saving priority(ESP).Moreover,the PGP and ESP strategies were further analyzed in the simulation of a dvPVBE.An office room integrated with a dvPVBE was modeled using EnergyPlus.The influence of the dvPVBE in improving the building energy efficiency and corresponding optimal slat angles was investigated under the PGP and ESP control strategies.The results indicate that the application of dvPVBEs in Beijing can provide up to 131%of the annual energy demand of office rooms and significantly increase the annual net energy output by at least 226%compared with static photovoltaic(PV)blinds.The concept of this novel dvPVBE offers a viable approach by which the thermal load,daylight penetration,and energy generation can be effectively regulated. 展开更多
关键词 Weather-responsive facades Building energy efficiency Dynamic photovoltaic integrated building envelopes(PVBEs) Building-integrated photovoltaics(BIPVs)
下载PDF
An envelope-based machine learning workflow for locating earthquakes in the southern Sichuan Basin
3
作者 Kang Wang Jie Zhang +2 位作者 Ji Zhang Zhangyu Wang Ziyu Li 《Earthquake Research Advances》 CSCD 2024年第2期45-54,共10页
The development of machine learning technology enables more robust real-time earthquake monitoring through automated implementations. However, the application of machine learning to earthquake location problems faces ... The development of machine learning technology enables more robust real-time earthquake monitoring through automated implementations. However, the application of machine learning to earthquake location problems faces challenges in regions with limited available training data. To address the issues of sparse event distribution and inaccurate ground truth in historical seismic datasets, we expand the training dataset by using a large number of synthetic envelopes that closely resemble real data and build an earthquake location model named ENVloc. We propose an envelope-based machine learning workflow for simultaneously determining earthquake location and origin time. The method eliminates the need for phase picking and avoids the accumulation of location errors resulting from inaccurate picking results. In practical application, ENVloc is applied to several data intercepted at different starting points. We take the starting point of the time window corresponding to the highest prediction probability value as the origin time and save the predicted result as the earthquake location. We apply ENVloc to observed data acquired in the southern Sichuan Basin, China, between September 2018 and March 2019. The results show that the average difference with the catalog in latitude, longitude, depth, and origin time is 0.02°,0.02°, 2 km, and 1.25 s, respectively. These suggest that our envelope-based method provides an efficient and robust way to locate earthquakes without phase picking, and can be used in earthquake monitoring in near-real time. 展开更多
关键词 Waveform envelope Earthquake location Local seismicity Synthetic data Sparse stations
下载PDF
Hepatitis B surface antigen-negative but hepatitis B envelope antigen-positive false occult hepatitis B virus infection:A case report
4
作者 Shu-Sheng Yang Fei Fu +4 位作者 Qian-Kun Xuan Zhou-Xiang Zhang Zhi-Jun Li Guang-Bo Li Xiao-Yu Yu 《World Journal of Hepatology》 2024年第10期1199-1207,共9页
BACKGROUND Occult hepatitis B infection(OBI)is characterized by the detection of hepatitis B virus(HBV)DNA in serum(usually HBV DNA<200 IU/mL)or the liver but negativity for hepatitis B surface antigen(HBsAg).The d... BACKGROUND Occult hepatitis B infection(OBI)is characterized by the detection of hepatitis B virus(HBV)DNA in serum(usually HBV DNA<200 IU/mL)or the liver but negativity for hepatitis B surface antigen(HBsAg).The diagnosis of OBI relies on the sensitivity of assays used in the detection of HBV DNA and HBsAg.HBsAg assays with inadequate sensitivity or inability to detect HBV S variants may lead to misdiagnosis of OBI in people with overt HBV infection.CASE SUMMARY We report a HBsAg-negative but hepatitis B envelope antigen-positive patient who had a significant HBV DNA level.The patient was initially diagnosed as having OBI.However,sequence analysis revealed a unique insertion of amino acid residues at positions 120-124 in the S protein,which affects the formation of a disulfide bond that is associated with the formation of a loop.It is well known that there is an overlap between the S protein and Pol protein.We found that this new insertion site occurred in polymerase/reverse transcriptase domain,indi-cating that this insertion might be involved in HBV pathogenicity.The patient was finally diagnosed with a false OBI.CONCLUSION An insertion of amino acid residues at positions 120-124 of the S protein affects the formation of immunodominant epitopes and results in negative HBsAg levels. 展开更多
关键词 Occult hepatitis B infection Hepatitis B virus Hepatitis B surface antigen Hepatitis B envelope antigen Immunodominant epitopes Case report
下载PDF
Data envelopment analysis for scale elasticity measurement in the stochastic case:with an application to Indian banking
5
作者 Alireza Amirteimoori Biresh K.Sahoo Saber Mehdizadeh 《Financial Innovation》 2023年第1期955-990,共36页
In the nonparametric data envelopment analysis literature,scale elasticity is evaluated in two alternative ways:using either the technical efficiency model or the cost efficiency model.This evaluation becomes problema... In the nonparametric data envelopment analysis literature,scale elasticity is evaluated in two alternative ways:using either the technical efficiency model or the cost efficiency model.This evaluation becomes problematic in several situations,for example(a)when input proportions change in the long run,(b)when inputs are heterogeneous,and(c)when firms face ex-ante price uncertainty in making their production decisions.To address these situations,a scale elasticity evaluation was performed using a value-based cost efficiency model.However,this alternative value-based scale elasticity evaluation is sensitive to the uncertainty and variability underlying input and output data.Therefore,in this study,we introduce a stochastic cost-efficiency model based on chance-constrained programming to develop a value-based measure of the scale elasticity of firms facing data uncertainty.An illustrative empirical application to the Indian banking industry comprising 71 banks for eight years(1998–2005)was made to compare inferences about their efficiency and scale properties.The key findings are as follows:First,both the deterministic model and our proposed stochastic model yield distinctly different results concerning the efficiency and scale elasticity scores at various tolerance levels of chance constraints.However,both models yield the same results at a tolerance level of 0.5,implying that the deterministic model is a special case of the stochastic model in that it reveals the same efficiency and returns to scale characterizations of banks.Second,the stochastic model generates higher efficiency scores for inefficient banks than its deterministic counterpart.Third,public banks exhibit higher efficiency than private and foreign banks.Finally,public and old private banks mostly exhibit either decreasing or constant returns to scale,whereas foreign and new private banks experience either increasing or decreasing returns to scale.Although the application of our proposed stochastic model is illustrative,it can be potentially applied to all firms in the information and distribution-intensive industry with high fixed costs,which have ample potential for reaping scale and scope benefits. 展开更多
关键词 Data envelopment analysis Stochastic data envelopment analysis Technical efficiency Returns to scale Economies of scale Scale elasticity Indian banking ECONOMETRICS ECONOMICS
下载PDF
Calibration of Four Nonlinear Failure Envelopes from Triaxial Test Data and Influence of Nonlinearity on Geotechnical Computations
6
作者 Amaechi J. Anyaegbunam Fidelis O. Okafor 《Geomaterials》 2021年第2期42-57,共16页
It is now recognized that many geomaterials have nonlinear failure envelopes. This non-linearity is most marked at lower stress levels, the failure envelope being of quasi-parabolic shape. It is not easy to calibrate ... It is now recognized that many geomaterials have nonlinear failure envelopes. This non-linearity is most marked at lower stress levels, the failure envelope being of quasi-parabolic shape. It is not easy to calibrate these nonlinear failure envelopes from triaxial test data. Currently only the power-type failure envelope has been studied with an established formal procedure for its determination from triaxial test data. In this paper, a simplified procedure is evolved for the development of four different types of nonlinear envelopes. These are of invaluable assistance in the evaluation of true factors of safety in problems of slope stability and correct computation of lateral earth pressure and bearing capacity. The use of the Mohr-Coulomb failure envelopes leads to an overestimation of the factors of safety and other geotechnical quantities. 展开更多
关键词 Calibration of Nonlinear Failure envelope Triaxial Test Data Modified Maksimovic envelope Power-Type envelope Polynomial-Type envelope Hoek-Brown envelope Standard Error of Estimate
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:4
7
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
Density-dependent carrier-envelope phase shift in attosecond pulse generation from relativistically oscillating mirrors 被引量:1
8
作者 Rishat Zagidullin Stefan Tietze +2 位作者 Matt Zepf Jingwei Wang Sergey Rykovanov 《Matter and Radiation at Extremes》 SCIE EI CSCD 2023年第6期41-48,共8页
The carrier-envelope phase(CEP)φ_(0)is one of the key parameters in the generation of isolated attosecond pulses.In particular,“cosine”pulses(φ_(0)=0)are best suited for generation of single attosecond pulses in a... The carrier-envelope phase(CEP)φ_(0)is one of the key parameters in the generation of isolated attosecond pulses.In particular,“cosine”pulses(φ_(0)=0)are best suited for generation of single attosecond pulses in atomic media.Such“cosine”pulses have the peak of the most intense cycle aligned with the peak of the pulse envelope,and therefore have the highest contrast between the peak intensity and the neighboring cycles.In this paper,the dynamics of single attosecond pulse generation from a relativistically oscillating plasma mirror is investigated.We use an elementary analytical model as well as particle-in-cell simulations to study few-cycle attosecond pulses.We find that the phase of the field driving the surface oscillations depends on the plasma density and preplasma scale length.This leads us to a counterintuitive conclusion:for the case of normal incidence and a sharp plasma-vacuum boundary,the CEP required for the generation of a single attosecond pulse phase is closer toφ_(0)=π/2(a“sine”pulse),with the exact value depending on the plasma parameters. 展开更多
关键词 envelopE OSCILLATING RELATIVISTIC
下载PDF
Failure Envelopes of Single-Plate Rigid Helical Anchors for Floating Offshore Wind Turbine
9
作者 CHEN Hong-zhen WANG Le +3 位作者 TIAN Ying-hui ZHANG Chun-hui SHEN Zhi-chao LIU Meng-meng 《China Ocean Engineering》 SCIE EI CSCD 2023年第6期1000-1010,共11页
Helical anchor is a kind of novel foundation for floating offshore wind turbines,which should be subjected to combined tensile loading caused by wind,wave and current.However,the research about the capacity of helical... Helical anchor is a kind of novel foundation for floating offshore wind turbines,which should be subjected to combined tensile loading caused by wind,wave and current.However,the research about the capacity of helical anchor was mainly examined under uniaxial loading and scarcely explored under combined loading.In this study,three-dimensional finite element limit analysis is adopted to assess the bearing capacities of single-plate rigid helical anchors with different ratios of helix to shaft diameter,D_(H)/D_(S) and embedment ratios L/D_(S).Result shows that the vertical,horizontal and moment bearing capacities increase with increasing D_(H)/D_(S) and L/D_(S).The normalized V-H failure envelopes expands with increasing L/D_(S),while the normalized V-M failure envelopes tend to contract with the increase of D_(H)/D_(S).With increasing D_(H)/D_(S) or decreasing L/D_(S),the normalized H-M failure envelopes expand when the horizontal and moment loading act in the same direction and contract when they act in the opposite direction.The effect of D_(H)/D_(S) and L/D_(S) on the shape of H-M failure envelope become insignificant when L/D_(S)≥4.A series of failure mechanisms under different loading conditions were observed and can be used to explain the trend.Besides,a series of approximate expressions were proposed to fit the uniaxial bearing capacities and the failure envelopes. 展开更多
关键词 helical anchors bearing capacity failure envelope CLAY
下载PDF
Intelligent Digital Envelope for Distributed Cloud-Based Big Data Security
10
作者 S.Prince Chelladurai T.Rajagopalan 《Computer Systems Science & Engineering》 SCIE EI 2023年第7期951-960,共10页
Cloud computing offers numerous web-based services.The adoption of many Cloud applications has been hindered by concerns about data security and privacy.Cloud service providers’access to private information raises mo... Cloud computing offers numerous web-based services.The adoption of many Cloud applications has been hindered by concerns about data security and privacy.Cloud service providers’access to private information raises more security issues.In addition,Cloud computing is incompatible with several industries,including finance and government.Public-key cryptography is frequently cited as a significant advancement in cryptography.In contrast,the Digital Envelope that will be used combines symmetric and asymmetric methods to secure sensitive data.This study aims to design a Digital Envelope for distributed Cloud-based large data security using public-key cryptography.Through strategic design,the hybrid Envelope model adequately supports enterprises delivering routine customer services via independent multi-sourced entities.Both the Cloud service provider and the consumer benefit from the proposed scheme since it results in more resilient and secure services.The suggested approach employs a secret version of the distributed equation to ensure the highest level of security and confidentiality for large amounts of data.Based on the proposed scheme,a Digital Envelope application is developed which prohibits Cloud service providers from directly accessing insufficient or encrypted data. 展开更多
关键词 Digital envelope Cloud computing big data ENCRYPTION DECRYPTION
下载PDF
Envelope Method and More General New Global Structures of Solutions for Multi-dimensional Conservation Law
11
作者 Gui-Qin Qiu Gao-Wei Cao +1 位作者 Xiao-Zhou Yang Yuan-An Zhao 《Communications on Applied Mathematics and Computation》 2023年第3期1180-1234,共55页
For the two-dimensional(2D)scalar conservation law,when the initial data contain two different constant states and the initial discontinuous curve is a general curve,then complex structures of wave interactions will b... For the two-dimensional(2D)scalar conservation law,when the initial data contain two different constant states and the initial discontinuous curve is a general curve,then complex structures of wave interactions will be generated.In this paper,by proposing and investigating the plus envelope,the minus envelope,and the mixed envelope of 2D non-selfsimilar rarefaction wave surfaces,we obtain and the prove the new structures and classifications of interactions between the 2D non-selfsimilar shock wave and the rarefaction wave.For the cases of the plus envelope and the minus envelope,we get and prove the necessary and sufficient criterion to judge these two envelopes and correspondingly get more general new structures of 2D solutions. 展开更多
关键词 Riemann problem Non-selfsimilar shock wave Non-selfsimilar rarefaction wave envelopE Multi-dimensional conservation law
下载PDF
Coherent Parameter Measurement Based on Partial Coherent Envelope Demodulation
12
作者 Chaoze Zhang Laiyang Dang +3 位作者 Tianyu Guan Yuqin Mao Ligang Huang Tao Zhu 《Optics and Photonics Journal》 2023年第6期133-139,共7页
The key parameters of laser energy concentration and coherence can be characterized by laser linewidth, which determines the detection range, measurement resolution and signal-to-noise ratio of laser precision measure... The key parameters of laser energy concentration and coherence can be characterized by laser linewidth, which determines the detection range, measurement resolution and signal-to-noise ratio of laser precision measurement technology. Up to now, the laser linewidth is mainly measured by the energy distribution width in the frequency domain, but the coherence of the laser has not been measured or characterized directly. In this work, we propose the concept of coherent linewidth based on the coherent envelope of delayed self-heterodyne detection to directly characterize the time-frequency coherence of lasers. In the proof-of-concept experiment, we obtain the coherence coefficient through the Fourier transform of the partial coherence envelope, and then measure the coherence linewidth of the laser. The measured coherent linewidth is smaller than the traditional integral linewidth and larger than the intrinsic Lorentzian linewidth, indicating that the coherent linewidth is less affected by low-frequency 1/f noise. The concept of coherent linewidth proposed in this article can serve as a candidate method for directly characterizing the coherence of narrow linewidth lasers. . 展开更多
关键词 Laser Linewidth Coherent Linewidth Coherent envelope
下载PDF
Comparative Studies on the Fine Structure and Elemental Composition of Envelopes of Trachelomonas and Strombomonas (Euglenophyta) 被引量:1
13
作者 王全喜 刘洪家 +3 位作者 于晶 孙世琴 张大维 包文美 《Acta Botanica Sinica》 CSCD 2003年第5期601-607,共7页
Fine structure and elemental composition of envelopes of 10 taxa of Trachelomonas and Strombomonas from natural freshwater bodies in China were studied and phylogeny of both genera were discussed. The results indicate... Fine structure and elemental composition of envelopes of 10 taxa of Trachelomonas and Strombomonas from natural freshwater bodies in China were studied and phylogeny of both genera were discussed. The results indicate that iron (Fe) and silicon (Si) are the primary mineral elements of the envelopes. Composition of mineral elements was uncorrelated with envelope color, however, it was highly correlated with the microarchitecture of the envelopes. Content of Si was higher than that of Fe in all species of Strombomonas and some species of Trachelomonas with rough surface. In most species of Trachelomonas, especially those with dense and smoothy surface, content of Fe was higher than that of Si. Based on the above results, we propose to assign those species of Strombomonas into Trachelomonas and consider them as a group of the latter. These species were the most primitive among the group with envelopes in Euglenaceae. 展开更多
关键词 Trachelomonas Strombomonas envelopE elemental composition fine structure
下载PDF
Elastic envelope inversion using multicomponent seismic data with filtered-out low frequencies 被引量:2
14
作者 黄超 董良国 迟本鑫 《Applied Geophysics》 SCIE CSCD 2015年第3期362-377,467,共17页
The absence of low-frequency information in seismic data is one of the most difficult problems in elastic full waveform inversion. Without low-frequency data, it is difficult to recover the long-wavelength components ... The absence of low-frequency information in seismic data is one of the most difficult problems in elastic full waveform inversion. Without low-frequency data, it is difficult to recover the long-wavelength components of subsurface models and the inversion converges to local minima. To solve this problem, the elastic envelope inversion method is introduced. Based on the elastic envelope operator that is capable of retrieving low- frequency signals hidden in multicomponent data, the proposed method uses the envelope of multicomponent seismic signals to construct a misfit function and then recover the long- wavelength components of the subsurface model. Numerical tests verify that the elastic envelope method reduces the inversion nonlinearity and provides better starting models for the subsequent conventional elastic full waveform inversion and elastic depth migration, even when low frequencies are missing in multicomponent data and the starting model is far from the true model. Numerical tests also suggest that the proposed method is more effective in reconstructing the long-wavelength components of the S-wave velocity model. The inversion of synthetic data based on the Marmousi-2 model shows that the resolution of conventional elastic full waveform inversion improves after using the starting model obtained using the elastic envelope method. Finally, the limitations of the elastic envelope inversion method are discussed. 展开更多
关键词 elastic wave multicomponent data elastic envelope full waveform inversion
下载PDF
Injective Envelopes of a Hilbert C~*Module
15
作者 许天周 蔡涛 李炳照 《Journal of Beijing Institute of Technology》 EI CAS 2001年第2期119-124,共6页
As in homology, the notion of injectivity is introduced in the category whose objects are Hilbert C * module over a C * algebra and whose morphism are bounded module operators. The definition of injective envelope... As in homology, the notion of injectivity is introduced in the category whose objects are Hilbert C * module over a C * algebra and whose morphism are bounded module operators. The definition of injective envelopes of an extension of a Hilbert C * modules over a C * algebra is introduced, and is characterized in terms of the injectivity and essence. It is shown that every Hilbert C * module has a unique (up to H isometrics) injective envelope if it exists. It is also shown that an extension of a Hilbert C * module is an injective envelope if and only if it is an injective and essential extension. Moreover, every Hilbert C * module over a W * algebra has a unique (up to H isometrics) injective envelope and the injective envelope of a Hilbert C * module H is maximal essential extension of H . 展开更多
关键词 C * algebra Hilbert C * module injective envelope
下载PDF
Enveloping algebras of generalized H-Hom-Lie algebras
16
作者 王圣祥 王栓宏 《Journal of Southeast University(English Edition)》 EI CAS 2015年第4期588-590,共3页
Let H be a Hopf algebra and HYD the Yetter- Drinfeld category over H. First, the enveloping algebra of generalized H-Hom-Lie algebra L, i.e., Hom-Lie algebra L H in the category HYD, is constructed. Secondly, it is o... Let H be a Hopf algebra and HYD the Yetter- Drinfeld category over H. First, the enveloping algebra of generalized H-Hom-Lie algebra L, i.e., Hom-Lie algebra L H in the category HYD, is constructed. Secondly, it is obtained that U(L) = T( L)/L where I is the Hom-ideal of T(L) generated by {ll'-l_((-1))·l'l_0-[l,l']|l,l'∈L}, and u: L,T(L)/I is the canonical map. Finally, as the applications of the result, the enveloping algebras of generalized H-Lie algebras, i.e., the Lie algebras in the category MyDn and the Hom-Lie algebras in the category of left H-comodules are presented, respectively. 展开更多
关键词 enveloping algebra generalized H-Hom-Li^algebra Yetter-Drinfeld category
下载PDF
INVESTIGATION OF AIR FLOW ON FLIGHT DECK AND SHIPBOARD OPERATION ENVELOPE 被引量:1
17
作者 孙文胜 高正 辛宏 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1995年第1期45-51,共7页
The Shipboard Operation Envelope(SOE) is the safe boundary of the helicopter/ship dynamic interface. The night deck on a ship is usually behind the hangar, where the airflow is turbulent due to the influence of the up... The Shipboard Operation Envelope(SOE) is the safe boundary of the helicopter/ship dynamic interface. The night deck on a ship is usually behind the hangar, where the airflow is turbulent due to the influence of the upper structure, wind and ship speed. The turbulent airnow is the major adverse factor for the safety of shipboard operations. In this paper, the night deck abbot is analysed as the superposition of two penyndicular 2-D airflows.N-S equations are used to calculate the velocity field and the range of turbulent airflow using finite element method. The result is correspondent well with test. Incorporating the influence of the airflow and giving some restrictions on the movements of the ship and on the control margin of the helicopter, the operation envelopes are calculated. The operation envelopes include three types for hovering over the deck, taking-off from and landing on ship, and landing with a landing-aid system. These results are helpful to the pilot training and night safety. 展开更多
关键词 HELICOPTER now field finite element operation envelope RESTRICTION
下载PDF
Frame Work of Data Envelopment Analysis—A Model to Evaluate the Environmental Efficiency of China'S Industrial Sectors 被引量:24
18
作者 TAO ZHANG 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2009年第1期8-13,共6页
Objective To evaluate the environmental and technical efficiencies of China's industrial sectors and provide appropriate advice for policy makers in the context of rapid economic growth and concurrent serious environ... Objective To evaluate the environmental and technical efficiencies of China's industrial sectors and provide appropriate advice for policy makers in the context of rapid economic growth and concurrent serious environmental damages caused by industrial pollutants. Methods A data of envelopment analysis (DEA) framework crediting both reduction of pollution outputs and expansion of good outputs was designed as a model to compute environmental efficiency of China's regional industrial systems. Results As shown by the geometric mean of environmental efficiency, if other inputs were made constant and good outputs were not to be improved, the air pollution outputs would have the potential to be decreased by about 60% in the whole China. Conclusion Both environmental and technical efficiencies have the potential to be greatly improved in China, which may provide some advice for policy-makers. 展开更多
关键词 Technical efficiency Environmental efficiency Directional distance function Technical-environmentalefficiency Data of envelopment analysis China
下载PDF
Fuzzy data envelopment analysis approach based on sample decision making units 被引量:11
19
作者 Muren Zhanxin Ma Wei Cui 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第3期399-407,共9页
The conventional data envelopment analysis (DEA) measures the relative efficiencies of a set of decision making units with exact values of inputs and outputs. In real-world prob- lems, however, inputs and outputs ty... The conventional data envelopment analysis (DEA) measures the relative efficiencies of a set of decision making units with exact values of inputs and outputs. In real-world prob- lems, however, inputs and outputs typically have some levels of fuzziness. To analyze a decision making unit (DMU) with fuzzy input/output data, previous studies provided the fuzzy DEA model and proposed an associated evaluating approach. Nonetheless, numerous deficiencies must still be improved, including the α- cut approaches, types of fuzzy numbers, and ranking techniques. Moreover, a fuzzy sample DMU still cannot be evaluated for the Fuzzy DEA model. Therefore, this paper proposes a fuzzy DEA model based on sample decision making unit (FSDEA). Five eval- uation approaches and the related algorithm and ranking methods are provided to test the fuzzy sample DMU of the FSDEA model. A numerical experiment is used to demonstrate and compare the results with those obtained using alternative approaches. 展开更多
关键词 fuzzy mathematical programming sample decision making unit fuzzy data envelopment analysis EFFICIENCY α-cut.
下载PDF
THE NOVEL ANNULAR ENVELOPE CYLINDRICAL WORM AND FUZZY OPTIMAL DESIGN OF ITS DRIVE
20
作者 李秀梅 李贵涛 +2 位作者 程福安 张鹏程 王树人 《Transactions of Tianjin University》 EI CAS 1997年第1期35-39,共5页
The cylindrical worm processed by annular grinding wheel envelope in two degree of freedom motion state is a novel worm. This paper explains the shaping principle of such a worm. To improve meshing quality and the p... The cylindrical worm processed by annular grinding wheel envelope in two degree of freedom motion state is a novel worm. This paper explains the shaping principle of such a worm. To improve meshing quality and the properties of contact and lubrication, the multi objective optimization has been conducted for the first time to the parameters of such a worm pair by the fuzzy optimal method. The results show that, the shape of the contact line is visibly more sloped than before being optimized, lubrication angle is apparently bigger, and the distribution of contact lines is much improved. 展开更多
关键词 two degree of freedom motion annular grinding wheel envelopE multi objective fuzzy optimization
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部