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Changes in sea ice kinematics in the Arctic outflow region and their associations with Arctic Northeast passage accessibility

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Acta Oceanologica Sinica 2019年第8期38卷 101-110页

作者： Dawei Gui Xiaoping Pang Ruibo Lei Xi Zhao Jia Wang Chinese Antarctic Center of Surveying and Mapping Wuhan University Wuhan 430079 China MNR Key Laboratory for Polar Science Polar Research Institute of China Shanghai 200136 China National Oceanic and Atmospheric Administration Great Lakes Environmental Research Laboratory Ann Arbor 48108-9719 USA

Amplification of climate warming in the Arctic is causing a dramatic retreat of sea ice, which means the Arctic sea routes are becoming increasingly accessible. This study used a satellite-derived sea ice motion product to quantify the kinematic features of sea ice in the Arctic outflow region which specially referred to the Fram Strait and to the north of the Northeast passage(NEP). An observed trend of increased southward sea ice displacement from the central Arctic to the Fram Strait indicated enhancement of the Transpolar Drift Stream(TDS). In the regions to the north of the NEP, the long-term trend of northward sea ice speed in the Kara sector was +0.04 cm/s per year in spring. A significant statistical relationship was found between the NEP open period and the northward speed of the sea ice to the north of the NEP. The offshore advection of sea ice could account for the opening of sea routes by 33% and 15% in the Kara and Laptev sectors, respectively. The difference in sea level pressure across the TDS,i.e., the Central Arctic Index(CAI), presented more significant correlation than for the Arctic atmospheric Dipole Anomaly index with the open period of the NEP, and the CAI could explain the southward displacement of sea ice toward the Fram Strait by more than 45%. The impact from the summer positive CAI reinforces the thinning and mechanical weakening of the sea ice in the NEP region, which improves the navigability of the NEP.

关键词： sea ice Arctic Northeast passage Transpolar Drift Stream atmospheric circulation indices

First passage failure of dynamical power systems under random perturbations

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Science China(Technological Sciences) 2010年第9期53卷 2495-2500页

作者： CHEN LinCong1 & ZHU WeiQiu2 1 College of Civil Engineering,Huaqiao University,Xiamen 361021,China 2 Department of Mechanics,State Key Laboratory of Fluid Power Transmission and Control,Zhejiang University,Hangzhou 310027,China College of Civil Engineering Huaqiao University Xiamen China Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou China

The first-passage problem of dynamical power system of a single-machine-infinite-bus (SMIB) system under random perturbations is studied.First,the stochastic averaging method for quasi non-integrable generalized Hamiltonian systems is applied to reduce the equations of the SMIB system under random perturbations to a set of averaged It equations.Then,the backward Kolmogorov equation governing the conditional reliability function and the Pontryagin equation governing the conditional mean of first passage time are established and solved numerically,respectively.Finally,the proposed method is verified by using the Monte Carlo simulation of the original system.

关键词： dynamical power system random perturbation stochastic averaging first passage failure

First passage times for Markov renewal processes and applications

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Science China Mathematics 2000年第12期43卷 1238-1249页

作者：徐光煇袁学明李泉林 Institute of Applied Mathematics Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Beijing 100080 China Asian-Pacific Operations Research Center within CAS and APORS Beijing 100080 China National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China

This paper proposes a uniformly convergent algorithm for the joint transform of the first passage time and the first passage number of steps for general Markov renewal processes with any initial state probability vector. The uniformly convergent algorithm with arbitrarily prescribed error can be efficiently applied to compute busy periods, busy cycles, waiting times, sojourn times, and relevant indices of various generic queueing systems and queueing networks. This paper also conducts a numerical experiment to implement the proposed algorithm.

关键词： Markov renewal process (MRP) joint transform first passage time busy period busy cycle uniform error.

First passage times: Busy periods and waiting times

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Science China Mathematics 1995年第10期38卷 1187-1201页

作者：徐光煇袁学明 Institute of Applied Mathematics Chinese Academy of Sciences Beijing 100080 China Asian-Pacific Operations Research Center within APORS and CAS Beijing 100080 China

General expressions of first passage times for denumerable Markov processes are discussed and computation problems for busy periods and waiting times for queues corresponding to Markov processes are studied. In particular, the simplified algorithms for busy periods and waiting times for queues corresponding to G//M/1 type and M/G/1 type Markov processes are derived and some numerical examples are presented.

关键词： denumerable Markov process first passage time G1/M/1 type Markov process M/G/1 Markov process M/G/1 type Markov process uniform error.

Sensitivity analysis of the vane length and passage width for a radial type swirler employed in a triple swirler configuration

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Theoretical & Applied Mechanics Letters 2019年第6期9卷 363-375页

作者： Foad Vashahi Shahnaz Rezaei Reza Alidoost Dafsari Jeekeun Lee Fluid Engineering Laboratory Department of Mechanical System EngineeringGraduate School of Chonbuk National UniversityJeonjuSouth Korea Division of Mechanical System Engineering Chonbuk National UniversityJeonjuSouth Korea

The design of axial or radial swirlers typically governs a number of geometrical parameters that are determined by the desired flow field.In the meantime,the number of unknown parameters increases with the number of concentrically mounted swirlers.The available literature is nonetheless limited,and designers are obligated to increase the number of initial assumptions.In this article,three kinds of triple swirlers are employed and simulations are performed to determine the effect of each parameter on the swirler performance.Based on the correlation provided,overlengthening the radial vane length could result in significant changes in the flow field from the jetlike pattern to a wide swirl-jet angle due to the Coanda effect.passage width should also have the potential to alter the swirl-jet angle and velocity field at the exit of the swirler.

关键词： Triple swirler Swirler design Radial vane length passage width Reynolds averaged Navier–Stokes

First passage times for multidimensional denumerable state Markov processes

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Chinese Science Bulletin 1999年第11期44卷 970-980页

作者： XU Guanghui(HSU Guang-Hui) and XU DejuInstitute of Applied Mathematics , Chinese Academy of Sciences , Beijing 100080, China Asian-Pacific Operations Research Center within CAS and APORS , Beijing 100080, China Institue of Applied Mathemics Chinese Academy of Sciences Beijing China Asian-Pacific Operations Research Center within CAS and APORS Beijing China

For a general multidimensional denumerable state Markov process with any initial state probability vector, the probability density function and its LS transform of the first passage time to a certain given state set are obtained and the algorithms for them are derived. It is proved that the resulting errors of the algorithms are both uniform in their respective arguments.Some numerical results are presented.

关键词： multidimensional denumerable state Markov process first passage time uniformization uniform error.

STUDY ON THE MOISTURE passage ON THE LOWER REACHES OF THE YARLUNG ZANGBO RIVER

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Science China Chemistry 1989年第5期32卷 580-593页

作者：杨逸畴高登义李渤生 Institute of Geography Academia Sinica Beijing Institute of Atmospheric Physics Academia Sinica Beijing Institute of Botany Academia Sinica Beijng

A series of gorges on the lower reaches of the Yarlung Zangbo River is like an enormous crevice splitting the southeastern Qinghai-Xizang (Tibet)Plateau to create a passage through which warm, wet air flow from the Indian Ocean reaches the inner part of the plateau. This moisture passage was mainly strengthened after the Pleistocene epoch in the Quaternary period and has played a major role in affecting the beginning date of the rainy season and the amount of the plateau’s rainfall. It has also served as a corridor for the living things on the southern and the northern sides of the Himalayas to mingle with each other. The region along this passage is abundant in evidences of species of differentiation, variation and biological division. Also the passage has provided a favorable environment for human beings and affected natural phenomena there.

关键词： moisture passage the Great Bend Gorge of the Yarlung Zangbo River the tectenic movement of the Qinghai-Xizang crust.

Failure of Aspired Understanding Among the Human Race——On the Theme of A passage to India

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陕西师范大学学报（哲学社会科学版） 2002年第S3期31卷 270-275页

作者：张晓霞陕西师范大学外国语学院陕西西安710062

The author attempts to interpret the theme of A Passsage to India by analyzing the major events and characterization. It is indicated in the thesis that E.M.Forster highlights the failure of aspired understanding between different races, different people and even within a person. In other words, in many cases people have aspirations for understanding, but in reality the real understanding is very difficult to fulfill.

关键词： I561.074 A passage to India understanding misunderstanding

passage,BLOCKADE,SINK AND SOURCE OF A PLANAR DYNAMICAL SYSTEM

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Chinese Annals of Mathematics,Series B 1992年第3期13卷 257-265页

作者：叶彦谦 Department of Mathematics Nanjing UniversityNanjing Jiangsu 210008China.

The author defines passage,blockade,sink and source of a plane multiply-connectedregion G with respect to a smooth dynamical system.Three theorems on the non-existenceor existence of closed orbits,and the existence of... 详细信息

关键词： passage SOURCE erior stated dynamical multiply 二忍 outer triangle shaded