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传送带输送物体时间问题小议
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作者 谢小华 《物理教学探讨(高一年级学研期)》 2005年第2期20-21,共2页
关键词 摩擦力 传送带输送物体时间问题 高一 物理 例题解析
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论后现代技术的品性和实践 被引量:3
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作者 张之沧 《江苏社会科学》 CSSCI 北大核心 2012年第2期23-28,共6页
以信息、语言、记忆工业和时间物体为代表的后现代技术,批判现代技术的机械化、商品化、功利化、权力化人类中心主义以及物化和异化带来的各类难以预测的事故和灾难。主张在非祛魅性、多元性、生态性和非决定论的后现代科学基础上,根除&... 以信息、语言、记忆工业和时间物体为代表的后现代技术,批判现代技术的机械化、商品化、功利化、权力化人类中心主义以及物化和异化带来的各类难以预测的事故和灾难。主张在非祛魅性、多元性、生态性和非决定论的后现代科学基础上,根除"技术官僚主义",推动后现代技术往更加人道、民主、自由、智慧和艺术的方向发展,将技术进一步人性化和真善美一体化,使其真正为新人民和全人类的文明服务。 展开更多
关键词 后现代技术 技术异化 记忆工业 时间物体 技术生成
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主动降低光照强度对暗适应及交通安全的影响 被引量:2
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作者 蔡光林 谢培 朱彤 《交通信息与安全》 2012年第1期99-102,共4页
为探索减轻驾驶员暗适应水平的方法,以不同速率主动降低光照强度,并测试光照强度突变为零后驾驶员辨识前方物体时间。建立室内实验环境;测量以不同速率提前降低光照强度的情况下,外界光照强度突变为零后驾驶员辨识前方物体的时间。根据... 为探索减轻驾驶员暗适应水平的方法,以不同速率主动降低光照强度,并测试光照强度突变为零后驾驶员辨识前方物体时间。建立室内实验环境;测量以不同速率提前降低光照强度的情况下,外界光照强度突变为零后驾驶员辨识前方物体的时间。根据数理统计原理,解析辨识时间与光照强度变化率之间的关系,分析提前改变光照强度对辨识时间的影响,寻找最短辨识时间及其相应的光照强度变化率。实验数据显示,提前降低光照强度7.0s以上与不降低相比,对驾驶员暗适应的作用显著且趋于稳定,驾驶员辨识前方物体时间最多可以减少61.91%。实验结果表明,提前改变光照强度对于短时间内缓解驾驶员暗适应现象有所帮助。 展开更多
关键词 交通安全 暗适应 光照强度 辨识物体时间 实验
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Scheduling transactions in mobile distributed real-time database systems 被引量:1
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作者 雷向东 赵跃龙 +1 位作者 陈松乔 袁晓莉 《Journal of Central South University of Technology》 EI 2008年第4期545-551,共7页
A DMVOCC-MVDA (distributed multiversion optimistic concurrency control with multiversion dynamic adjustment) protocol was presented to process mobile distributed real-time transaction in mobile broadcast environment... A DMVOCC-MVDA (distributed multiversion optimistic concurrency control with multiversion dynamic adjustment) protocol was presented to process mobile distributed real-time transaction in mobile broadcast environments. At the mobile hosts, all transactions perform local pre-validation. The local pre-validation process is carried out against the committed transactions at the server in the last broadcast cycle. Transactions that survive in local pre-validation must be submitted to the server for local final validation. The new protocol eliminates conflicts between mobile read-only and mobile update transactions, and resolves data conflicts flexibly by using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Mobile read-only transactions can be committed with no-blocking, and respond time of mobile read-only transactions is greatly shortened. The tolerance of mobile transactions of disconnections from the broadcast channel is increased. In global validation mobile distributed transactions have to do check to ensure distributed serializability in all participants. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols in terms of miss rate, restart rate, commit rate. Under high work load (think time is ls) the miss rate of DMVOCC-MVDA is only 14.6%, is significantly lower than that of other protocols. The restart rate of DMVOCC-MVDA is only 32.3%, showing that DMVOCC-MVDA can effectively reduce the restart rate of mobile transactions. And the commit rate of DMVOCC-MVDA is up to 61.2%, which is obviously higher than that of other protocols. 展开更多
关键词 mobile distributed real-time database systems muliversion optimistic concurrency control multiversion dynamic adjustment pre-validation multiversion data broadcast
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Reaction mechanism between“memory effect”and induction time of gas hydrate formation 被引量:1
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作者 孙登林 吴强 张保勇 《Journal of Coal Science & Engineering(China)》 2008年第2期280-282,共3页
Abstract Using visual experimental apparatus, one system (T40, 1×10^-3 mol/L, nonadded with coal) and another system (T40, 2×10^-3 mol/L, added with coal) were experimented with for three times and two t... Abstract Using visual experimental apparatus, one system (T40, 1×10^-3 mol/L, nonadded with coal) and another system (T40, 2×10^-3 mol/L, added with coal) were experimented with for three times and two times, respectively. Five groups of P-T experimental parameters were obtained using the data logger system and analyzed combined with the video information of the experiments. Major conclustions show that the induction time is shortened by 10-20 times in the experimental system containing residual pentahedral ring structures; "memory effect" can accelerate the dynamic progress and improve the thermodynamic conditions of gas hydrate formation. 展开更多
关键词 memory effect induction time thermodynamic condition gas hydrate
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Temporally Consistent Depth Map Estimation for 3D Video Generation and Coding 被引量:2
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作者 Sang-Beom Lee Yo-Sung Ho 《China Communications》 SCIE CSCD 2013年第5期39-49,共11页
In this paper, we propose a new algorithm for temporally consistent depth map estimation to generate three-dimensional video. The proposed algorithm adaptively computes the matching cost using a temporal weighting fun... In this paper, we propose a new algorithm for temporally consistent depth map estimation to generate three-dimensional video. The proposed algorithm adaptively computes the matching cost using a temporal weighting function, which is obtained by block-based moving object detection and motion estimation with variable block sizes. Experimental results show that the proposed algorithm improves the temporal consistency of the depth video and reduces by about 38% both the flickering artefact in the synthesized view and the number of coding bits for depth video coding. 展开更多
关键词 three-dimensional television multiview video depth estimation temporal consistency temporal weighting function
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A Few Remarks on Milburn Equation
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作者 CHEN Jun-Hua FAN Hong-Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第7期85-87,共3页
After presenting the infinite operator-sum form solution to the Milburn equation dp/dt=γ(UρU^f - ρ)=γU[p, Uf], where U=e^-iH/hγ, and verifying that this equation preserves the three necessary conditions of dens... After presenting the infinite operator-sum form solution to the Milburn equation dp/dt=γ(UρU^f - ρ)=γU[p, Uf], where U=e^-iH/hγ, and verifying that this equation preserves the three necessary conditions of density operators during time evolution, we prove that the yon Neumann entropy increases with time. We also point out that if A and B both obey the Milburn equation, then theproduct AB obeys (d/dt)(AB) = γU[AB, U^f]-(1/γ)(dA/dt)(dB/dt), which violates the Milburn equation, this reflects that a pure state will evolve to a mixture in general 展开更多
关键词 Milburn equation density operator EVOLUTION von Neumann entropy
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Retrieval of Electron Return Time from High-order Harmonics Generated in a Mixture of He and Ne Gases 被引量:1
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作者 金成 周效信 赵松峰 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第4期735-741,共7页
In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwel... In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwell's equation of harmonic field. And then we show the validity of mixture formulation by Wagner et al. [Phys. Rev. A 76 (2007) 061403(R)] in macroscopic response level. Finally, using/east squares fitting we retrieve the electron return time of short trajectory by formulation in Kanai et al. [Phys. Rev. Lett. 98 (2007) 153904] when the gas jet is put after the laser focus. 展开更多
关键词 high-order harmonic generation Maxwell's equation Lewenstein model return time
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Maize Seeds Submitted to Thermotherapy and Analyzed by Dynamic Speckle
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作者 Lucas Sacramoni Peixoto Gisela Maiara Silva +3 位作者 Armando Kazuo Fujii Joao José Dias Parisi Rosa Helena Aguiar Juliana Aparecida Fracarolli 《Journal of Agricultural Science and Technology(B)》 2018年第2期115-121,共7页
The quality of the seeds used for sowing is fundamental for a high productivity and quality of the crop. Therefore, eradicating pathogens is essential for the plant to develop in the best possible way. The eradicatio... The quality of the seeds used for sowing is fundamental for a high productivity and quality of the crop. Therefore, eradicating pathogens is essential for the plant to develop in the best possible way. The eradication of those pathogens can be accomplished by means of treatments that consist of the application of substances to the seeds or by performing physical procedures. Thermotherapy is a physical treatment, in which the seed is exposed to a given thermal energy, such as heated air or steam, and can be highly efficient for controlling those pathogens, in addition to reducing environmental damage and costs. The present work aimed to evaluate the efficiency of thermotherapy in two ways: wet heat (water) and dry heat (water vapor), both at 60 °C, alternating the exposure time to the thermal sources. The treatment with humid heat with a time of exposure of 5 min was the most efficient, since it presented higher germination percentages (83%) and less occurrence of Fusarium sp. (33%). It was observed that the most efficient thermotherapy is in the control of Fusarium, the most aggressive is for the quality of the seed. The quality of the treatments was evaluated through standard methodologies, according to the rules for seed analysis, such as germination and sanitation tests. Biospeckle laser was used to identify the microbial activity in these seeds, through activity maps generated by laser speckle contrast analysis (LASCA) processing. In this way, the research involving thermotherapy can be done by varying the temperature and the time of exposure to obtain values that considerably reduce the pathogenic agents and preserve the quality, in order to maintain the values of germination and vigor acceptable for commercialization. 展开更多
关键词 Thermal treatment wet heat dry heat FUSARIUM germination.
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The off-host survival and viability of a native and non-native fish louse (Argulus, Crustacea: Branchiura) 被引量:1
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作者 P.D. WALKER I.J. RUSSON +2 位作者 R. DUIJF G. VAN DER VELDE S.E. WENDELAAR BONGA 《Current Zoology》 SCIE CAS CSCD 北大核心 2011年第6期828-835,共8页
Fish ectoparasites are introduced to water bodies or aquaculture systems along with their hosts. Argulid fish lice can survive off-host for a given time, and in spite of quarantine measures might also be introduced vi... Fish ectoparasites are introduced to water bodies or aquaculture systems along with their hosts. Argulid fish lice can survive off-host for a given time, and in spite of quarantine measures might also be introduced via the transfer of water. However, they must cope with varying abiotic conditions without access to food. We investigated the effect of temperature (5 to 28℃) on the off-host survival time of Argulus japonicus, an invasive species which is apparently increasing its distribution, and compared this with the European A. foliaceus. A clear effect of temperature on the off-host survival time of all stages of both species was demonstrated. Larval and juvenile A. japonicus survived up to 9 days at 22℃ and in the case of adults up to 13 days at 15℃. By comparison, larval A. foliaceus survived up to 5 days at 15℃, adults up to 14 days at 9℃ and juveniles up to 7 days at 9℃ and 15℃. Thus, A. japonicus is more resistant to starvation at higher temperatures under controlled off-host conditions and A. foli- aceus is more resistant to starvation at lower temperatures. Infectivity of A. japonicus decreased linearly with the time spent off-host after 2 days for larvae and 4 days for adults. Temperature only had a significant effect on the infectivity of both develop- mental stages after 24 hours off-host between 13-23℃ for larvae and 13-18℃ for adults. In conclusion both species can potentially survive off-host pelods in water transports for up to 13-14 days as adults. Their survival is shorter as larvae. This study demonstrates that transportation of water has the potential to introduce Argulus species 展开更多
关键词 Argulus Fish lice SURVIVAL Temperature Off-host Water transport Introductions Invasive species
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Unsupervised Spatio-Temporal Segmentation for Extracting Moving Objects in Video Sequences 被引量:1
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作者 李仁杰 余松煜 王向文 《Journal of Shanghai Jiaotong university(Science)》 EI 2009年第2期154-161,共8页
Extraction of moving objects is an important and fundamental research topic for many video applications. This paper addresses an unsupervised spatio-temporal segmentation scheme to extract moving objects from video se... Extraction of moving objects is an important and fundamental research topic for many video applications. This paper addresses an unsupervised spatio-temporal segmentation scheme to extract moving objects from video sequences.The temporal segmentation localizes moving objects by comparing the motion vector of each block in each frame with the corresponding global motion vector estimated by an outlier rejection(OR) based method.Furthermore,the temporal compensation utilizing the temporal coherence of moving objects is considered in the temporal segmentation to solve the temporarily stopping problem.The detected moving regions usually have discontinuous boundaries and some holes.These regions are then compensated in the spatial domain. In the spatial segmentation,the watershed algorithm considering the global information improves the accuracy of segmentation in the spatial domain.The modified mean filter is presented to suppress some minima.By using a fusion module,moving objects are extracted.Experiments on various sequences have successfully demonstrated the validity of the proposed scheme. 展开更多
关键词 SEGMENTATION SPATIO-TEMPORAL region growing outlier rejection WATERSHED
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Qi,Time and Acupuncture
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作者 Axel SLOPEK 冯海涛 《Journal of Acupuncture and Tuina Science》 2009年第2期75-79,共5页
There is a strong relation among qi, time, and acupuncture. This relation is so close, that it can be said it is of yin-yang nature. Qi stands for yin, time for yang. This fact and its application in acupuncture are k... There is a strong relation among qi, time, and acupuncture. This relation is so close, that it can be said it is of yin-yang nature. Qi stands for yin, time for yang. This fact and its application in acupuncture are known since the times, the Huang Di Nei Jing (Yellow Emperor's Inner Canon) was written. The theory of time-related acupuncture, referred to as traditional Chinese chronotherapeutics or chronoacupuncture. In order to achieve better results in acupuncture, time-related acupuncture methods as represented in traditional Chinese chronotherapeufics should be applied in clinic regularly. Furthermore, they should become compulsory for the study of acupuncture. 展开更多
关键词 Acuptmcture Therapy AGING REGENERATION CHRONOBIOLOGY CHRONOTHERAPY QI Body Rhythm
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Fabrication and properties of ultraviolet photo-detectors based on SiC nanowires 被引量:2
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作者 PENG Gang ZHOU YingQiu +2 位作者 HE YanLan YU XiaoYan LI GongYi 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第7期1168-1171,共4页
A new type of ultraviolet photo-detectors (UVPDs) based on a bundle of highly aligned SiC nanowires was fabricated and the photo-electric properties of the UVPDs including 1-V characteristics and time response were ... A new type of ultraviolet photo-detectors (UVPDs) based on a bundle of highly aligned SiC nanowires was fabricated and the photo-electric properties of the UVPDs including 1-V characteristics and time response were studied in this work. SiC nan- owires were prepared by pyrolysis of a polymer precursor with ferrocene as the catalyst by a CVD route. The diameters of SiC nanowires varied from 100 to 200 nm while they were some centimeters long and the SiC nanowires were with zinc blended cubic form (β-SiC) tested by X-ray diffraction. A bundle of nanowires was fixed onto two legs' base by conductive silver paste to form the UVPDs. The electrical measurement of the device showed a significant increase of current when the device was exposed to 254 nm UV light, and the rising time of the device is very short, but the falling time is relatively long. Our results show that the UVPDs based on SiC nanowires have excellent electrical and optical properties which can be potentially applied. 展开更多
关键词 ultraviolet photo-detectors (UVPDs) SiC nanowires photo-electric property
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Multiple-relaxation-time lattice Boltzmann model for binary mixtures of nonideal fluids based on the Enskog kinetic theory 被引量:2
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作者 Kang Yang Zhaoli Guo 《Science Bulletin》 SCIE EI CAS CSCD 2015年第6期634-647,M0004,共15页
In this paper, a lattice Boltzmann equation (LBE) model with multiple-relaxation-time (MRT) colli- sion operator is developed based on the Enskog theory for isothermal nonideal mixtures, which is an extension of t... In this paper, a lattice Boltzmann equation (LBE) model with multiple-relaxation-time (MRT) colli- sion operator is developed based on the Enskog theory for isothermal nonideal mixtures, which is an extension of the previous single relaxation time (SRT) LBE model (Guo and Zhao in Phys Rev E 68:035302, 2003). The present MRT-LBE model overcomes some inherent defects of the original SRT-LBE model such as the fixed Schmidt num- ber and limited viscosity ratio. It is also interestingly shown that the widely used Shan-Chen (SC) model, which is constructed heuristically based on the pseudo-potential concept, can also be regarded as a special case of the present model, and thus putting a solid foundation for this well-accepted multiphase LBE model. A series of nu- merical simulations, including the static droplet and lay- ered co-current flow, are conducted to test the applicability of the present model for immiscible fluids with different Schmidt numbers and large viscosity ratio, which may be difficult for the original SRT-LBE model and the SC model. 展开更多
关键词 Lattice Boltzmann equation Enskogequation Bhatnagar-Gross-Krook Singlerelaxation time Multiple-relaxation-time
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A SINGULAR BIOECONOMIC MODEL WITH DIFFUSION AND TIME DELAY
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作者 Qingling ZHANG Xue ZHANG Chao LIU 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2011年第2期277-290,共14页
This paper studies a prey-predator singular bioeconomic system with time delay and diffusion, which is described by differential-algebraic equations. For this system without diffusion, there exist three bifurcation ph... This paper studies a prey-predator singular bioeconomic system with time delay and diffusion, which is described by differential-algebraic equations. For this system without diffusion, there exist three bifurcation phenomena: Transcritical bifurcation, singularity induced bifurcation, and Hopf bifurcation. Compared with other biological systems described by differential equations, singularity induced bifurcation only occurs in singular system and usually links with the expansion of population. When the diffusion is present, it is shown that the positive equilibrium point loses its stability at some critical values of diffusion rate and periodic oscillations occur due to the increase of time delay. Furthermore, numerical simulations illustrate the effectiveness of results and the related biological implications are discussed. 展开更多
关键词 DIFFUSION hopf bifurcation singular bioeconomic model singularity induced bifurcation time delay transcritical bifurcation.
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