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Precipitation variation in the northeastern Tibetan Plateau recorded by the tree rings since 850 AD and its relevance to the Northern Hemisphere temperature

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Science China Earth Sciences 2006年第4期49卷 408-420页

作者： John k. k.tzbach Center for Climatic Research University of Wisconsin-Madison Madison 53706 USA

Three well-dated Sabina Przewalsk.i ring-width chronologies from Dulan, China, have been used to reconstruct annual precipitation (from prior July to current June) variations on the northeast Tibetan Plateau since 850 AD. The reconstructions account of the instrumentally recorded precipitation variance are: 54.7% for the period of 1385-2000AD; 50.5% for 1099-1384AD and 45.7% for 850-1098AD. On the millenary scale, the precipitation variation over this region displays “W” shape, which has three peak. and two valleys. The precipitation is low during 1571-1879 AD, and high during 1880-2000 AD. 1900-2000 AD is the century with the highest precipitation over the northeast Tibetan Plateau in the last 1000 years, and 1962-2000 is the period with the highest pre- cipitation, and the highest variability of precipitation as well in the last 1000 years. The reconstructed series also reveals that the variability of annual precipitation is large when the precipitation is more, and contrarily, variability is small when the precipitation is low. With the temperature increasing obvi- ously in the 20th century, the precipitation in the study region significantly increased too, the variability of precipitation became larger, and drought and flooding occurred more frequently. The yearly tree-ring width (high frequency signal) series in this region reflects the local annually precipitation variation. However, the series with 40-year moving average (low frequency signal) cor- responds to the Northern Hemisphere temperature variations on the decadal to centurial scale. It correlates significantly with seven temperature curves of the Northern Hemisphere in the different time spans. For example, the correlation coefficients with the most temperature curves are around 0.9 during the period of 1852-1982 AD. In general, the temperature and the precipitation change syn- chronously in the Dulan region. It means that low temperature corresponds to low precipitation, andvice versa. This relations

关键词： Dulan China, Sabina Przewalsk.i, annual precipitation, the Northern Hemisphere temperature.

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Joint rate control and scheduling for wireless uplink.video streaming

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第5期7卷 801-810页

作者： k.TSAGGELOS Aggelos k. Department of Electrical Engineering & Computer Science Northwestern University Evanston Illinois 60208 USA

We solve the problem of uplink.video streaming in CDMA cellular network. by jointly designing the rate control and scheduling algorithms. In the pricing-based distributed rate control algorithm, the base station announces a price for the per unit average rate it can support, and the mobile devices choose their desired average transmission rates by balancing their video quality and cost of transmission. Each mobile device then determines the specific video frames to transmit by a video summarization process. In the time-division-multiplexing (TDM) scheduling algorithm, the base station collects the information on frames to be transmitted from all devices within the current time window, sorts them in increasing order of deadlines, and schedules the transmissions in a TDM fashion. This joint algorithm tak.s advantage of the multi-user content diversity, and maximizes the network.total utility (i.e., minimize the network.total distortion), while satisfying the delivery deadline constraints. Simulations showed that the proposed algorithm significantly outperforms the constant rate provision algorithm.

关键词： Video streaming, Pricing, Uplink communications, CDMA, Cross-layer design, Video summarization

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The neutron star zoo

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Frontiers of physics 2013年第6期8卷 679-692页

作者： Alice k. Harding Astrophysics Science Division NASA Goddard Space Flight Center Greenbelt MD 20771 USA

Neutron stars are a very diverse population, both in their observational and their physical properties. They prefer to radiate most of their energy at X-ray and gamma-ray wavelengths. But whether their emission is powered by rotation, accretion, heat, magnetic fields or nuclear reactions, they are all different species of the same animal whose magnetic field evolution and interior composition remain a mystery. This article will broadly review the properties of inhabitants of the neutron star zoo, with emphasis on their high-energy emission.

关键词： stars neutron stars pulsars binary stars

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Elimination of boundary effect for laminated overburden model in pillar stability analysis

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Journal of Central South University 2016年第6期23卷 1468-1473页

作者：张鹏 k. A. Heasley Carlson Software Watertown MA 02472 USA Department of Mining Engineering West Virginia University WV 26505 USA

The laminated overburden model(La Model)has been widely used for pillar design and stability *** a boundary element program,the La Model program is sensitive to the boundary condition,which should be considered before creating the *** eliminate the boundary effect in a La Model pillar stability analysis,a suitable boundary buffer zone is needed around the model *** radius of influence(R)and the abutment load extent(D)are two major factors that affect the stresses and displacements calculated in LaM *** determine the optimum buffer zone extent,a database of case histories was analyzed using the La Model *** for R and D were varied until a buffer zone having negligible influence on the pillar stability factor(SF)of the active mining zone(AMZ)was determined.

关键词： pillar stability boundary effect LaModel numerical simulation room-and-pillar

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Solvent effects on hydrogen bonding between primary alcohols and esters

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1928-1931页

作者： DHARMALINGAM k. RAMACHANDRAN k. SIVAGURUNATHAN P. Department of Physics Annamalai University Annamalai Nagar 608002 Tamilnadu India

The interaction by hydrogen bond formation of some primary alcohols （ l-heptanol, l-octanol and l-decanol） with esters （methyl methacrylate, ethyl methacrylate and butyl methacrylate） was investigated in non-polar solvents viz., n-heptane, CC14 and benzene by means of FTIR spectroscopy. Formation constants and free energy changes of complex formation were determined. The dependence of the equilibrium constants and free energy changes of complex formation on the alk.l chain length of both the alcohols and esters are discussed. The solvent interaction between the solute and solvent. effect on the hydrogen bond formation is discussed in terms of specific

关键词： FTIR spectroscopy Primary alcohols Esters Hydrogen bonding Solvent effect

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A cellular automata traffic flow modeling of desired speed variability

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Chinese Physics B 2013年第1期22卷 574-577页

作者： k. Bentaleb k. Jetto H. Ez-Zahraouy A. Benyoussef Laboratoire de Magnétisme et de Physique des Hautes Energies associéau CNRST (URAC 12) Département de physique B.P. 1014 Facultédes sciences Université Mohammed V Agdal Rabat Morocco Ecole Hassania des Travaux Publics k. 7 Route d'El Jadida BP8108 Oasis Casablanca Morocco Institute of Nanomaterials and Nanotechnologies INANOTECH MACsIR Rabat Morocco Hassan II Academy of Science and Technology Rabat Morocco

The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method. It is found that at low density the satisfaction rate depends on the maximal velocity. However, the behavior of the satisfaction rate as a function of the coefficient of variance is independent of the maximal velocity. This is in good agreement with empirical results obtained by Lipshtat [Phys. Rev. E 79 066110 （2009）]. Furthermore, our numerical result demonstrates that at low density the satisfaction rate tak.s higher values, whereas the coefficient of variance is close to zero. The coefficient of variance increases with increasing density, while the satisfaction rate decreases to zero. Moreover, we have also shown that, at low density the coefficient variance depends strongly on the probability of overtak.ng.

关键词： traffic celluar automata satisfaction coefficient desired speed

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On the invariance of time-dependent Hamilton's functions

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Acta Mechanica Sinica 2005年第5期21卷 511-513页

作者： Q. k. Ghori Department of Mathematics COMSATS Institute of Information TechnologyIslamabad Pakistan

The general framework.of Poincarè＇s formalism is used to establish the connection between conservation laws and invariance properties of Hamilton＇s function under infinitesimal transformations when these laws and t... 详细信息

关键词： Conservation law . Poincarè's formalism .Infinitesimal transformation

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PV Solar Yield Applicable Simulator Based on Free Irradiance Data Source:Applied Comprehensive Tool for Solar Engineers

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Energy Engineering 2023年第4期120卷 885-909页

作者： Ahmed Mohamed Ragab Abdelhalim Abdelnaby Zek.y Ashraf yahia Hassan Faculty of Engineering Communication SectionBenha UniversityBenha13511Egypt Faculty of Engineering Communication SectionAin Shams UniversityCairo11566Egypt

Accurate PV system simulators are implemented with expensive software platforms using paid irradiance *** main purpose of this paper is to develop and validate a PV system simulator,beginning with a solar cell parameter extraction model,then test and validate long-termIrradiance data using free online source(Typical Meteorological Year TMY in(PVGIS)European website),and finally building full solar generator simulator to run in work.ng real *** results with Accurate Paid PV simulators(which use theMuneer model)showed good accuracy of the proposed *** flow starts with the Irradiance model’s data processing,then solar cell 5 parameters model data processing(to extract cell parameters),and finally full system *** coding programs in real work.ng conditions are used for *** of solar cell parameter extraction show 99.6%to 99.99%matching with data sheet and cell performance under standard test *** simulation output shows 8%less yearly generated energy compared to the PVGIS 2022 long-term simulation(hourly basis(one-year time)).This is due to incident energy variations(between the years 2016 and 2022)of 4.02%.The novelty of the algorithm is the methodology,as it tests irradiance data on an hourly basis and validates results for a whole continuous ***,the 5-parameter solar cell model is used to be validated in long term analysis,not only STC conditions and could be applied on any PV solar *** algorithm and block.diagramused are scalable,modular,and interchangeable with similarmodels to be *** simulator could test severalmethods andmodels in solar pv technology.

关键词： Photovoltaics solar systems solar cell parameters extraction solar simulationmodel irradiancemodels solar yield long term analysis

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Demonstration of essentiality of entanglement in a Deutsch-lik. quantum algorithm

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Science China(Physics,Mechanics & Astronomy) 2018年第6期61卷 1-7页

作者： He-Liang Huang Ashutosh k. Goswami Wan-Su Bao Prasanta k. Panigrahi Chinese Academy Sciences Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China Hefei National Laboratory for Physical Sciences at Microscale Department of modern Physics University of Science and Technology of China Hefei 230026 China Indian Institute of Science Education and Research k.lk.ta Mohanpur 741 246 India

Quantum algorithms can be used to efficiently solve certain classically intractable problems by exploiting quantum ***, the effectiveness of quantum entanglement in quantum computing remains a question of debate. This study presents a new quantum algorithm that shows entanglement could provide advantages over both classical algorithms and quantum algorithms without entanglement. Experiments are implemented to demonstrate the proposed algorithm using superconducting *** show the viability of the algorithm and suggest that entanglement is essential in obtaining quantum speedup for certain problems in quantum computing. The study provides reliable and clear guidance for developing useful quantum algorithms.

关键词： quantum computing quantum entanglement quantum algorithm Deutsch's problem

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Experimental investigation on strip inserts in a circular tube heat transfer effect of conical under laminar flow

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Frontiers in Energy 2016年第2期10卷 136-142页

作者： M. ARULPRAk.SAJOTHI k. ELANGOVAN k. HEMA CHANDRA REDDY S. SURESH Department of Mechanical Engineering Jawaharlal Nehru Technologi-cal University Anantapur Anantapur 515002 India Department of Mechanical Engineering Cambridge Institute ofTechnology Bangalore 560036 India Department of Mechanical Engineering National Institute of Technology Trichy 620015 India

The aim of this paper is to observe the Nusselt number and friction factor behavior of the circular tube with conical strip inserts as turbulators in a laminar flow condition, using staggered and non-staggered conical strips with three different twist ratios （Y = 2, 3 and 5）. The conical strip is inserted in the forward and back.ard direction individually compared to the flow of water which is the work.ng fluid. The results indicate that the conical strip inserts increases the Nusselt number when compared to the plain surface tube. It is observed that the strip geometry has a major effect on the thermal performance of the circular tube. On examination of different strips for determining the enhancement of Nusselt number, the staggered conical strip with the twist ratio of Y = 3 has given a better result compared to the other two strips. Finally, correlations have been derived using regression analysis for predicting the Nusselt number and friction factor.

关键词： Nusselt number friction factor conical strip

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