3,782 research outputs found

    China and the United States: Towards a New Model of Major Power Relations?

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    The China-US disagreement over the term of 'new model of major power relations' is not just about discourse; rather, it is about who will have the upper hand in defining the terms for future China-US relations. While the Chinese want to provide a new vision and an alternative to the realist discourse of future China-US relations, the Americans believe that Beijing tries to claim a position on par with the United States in world affairs.postprin

    Explaining Change and Stability in Cross-Strait Relations: A Punctuated Equilibrium Model

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    Relations across the Taiwan Strait have experienced several cycles over the last 60 years. Tension and crisis seem to come and go, followed by periods of peace and stability. What explains the cyclical pattern of change and stability? How can we explain the sources of change and stability in the relationship? This article examines the last 60 years of cross-Strait relations in light of an interpretative framework of ‘punctuated equilibrium’. Cross-Strait relations are complex, consisting of actors at the domestic, cross-Strait, and international levels. With a high degree of economic interaction, the cross-Strait relationship can be characterized as economic integration cum political impasse. This article analyzes the cyclical changes through three causal factors: (a) the role of issue cycles in cross-Strait relations; (b) the impulsive drivers for change; and (c) the structural constraints dampening change.postprin

    Xi Jinping‘s 'Big Power Diplomacy’ and China’s Central National Security Commission (CNSC)

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    The current Chinese foreign and national security system suffers from problems of inefficiency, a lack of coordination and information sharing, and accountability of decision makers. China’s newly established Central National Security Commission (CNSC) is designed to build a strong platform to coordinate national security work and to strengthen unified leadership of national security at the central level. This article examines the CNSC’s foreign policy and institutional rationales. It argues that the establishment of the CNSC must be viewed in light of China’s growing power and Xi’s aspiration to play ‘big power diplomacy’ in world affairs as well as his ambition for overall institutional reforms of foreign and national security policymaking in China

    Analysis methods for collaborative models and activities

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    Abstract. A classification of analysis methods for CSCL systems is presented which uses as one dimension the distinction into summary analysis and structural analysis and as another distinction different types of raw data: either user actions or state descriptions. The Cool Modes environment for collaborative modeling enables us to explore the whole spectrum of analysis methods. Action logging is based on the MatchMaker communication server underlying Cool Modes. Example instances for several analysis methods have been implemented in the Cool Modes framework.

    Diffusion dominated process for the crystal growth of a binary alloy

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    The pure diffusion process has been often used to study the crystal growth of a binary alloy in the microgravity environment. In the present paper, a geometric parameter, the ratio of the maximum deviation distance of curved solidification and melting interfaces from the plane to the radius of the crystal rod, was adopted as a small parameter, and the analytical solution was obtained based on the perturbation theory. The radial segregation of a diffusion dominated process was obtained for cases of arbitrary Peclet number in a region of finite extension with both a curved solidification interface and a curved melting interface. Two types of boundary conditions at the melting interface were analyzed. Some special cases such as infinite extension in the longitudinal direction and special range of Peclet number were reduced from the general solution and discussed in detail

    A review of physical supply and EROI of fossil fuels in China

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    This paper reviews China’s future fossil fuel supply from the perspectives of physical output and net energy output. Comprehensive analyses of physical output of fossil fuels suggest that China’s total oil production will likely reach its peak, at about 230 Mt/year (or 9.6 EJ/year), in 2018; its total gas production will peak at around 350 Bcm/year (or 13.6 EJ/year) in 2040, while coal production will peak at about 4400 Mt/year (or 91.9 EJ/year) around 2020 or so. In terms of the forecast production of these fuels, there are significant differences among current studies. These differences can be mainly explained by different ultimately recoverable resources assumptions, the nature of the models used, and differences in the historical production data. Due to the future constraints on fossil fuels production, a large gap is projected to grow between domestic supply and demand, which will need to be met by increasing imports. Net energy analyses show that both coal and oil and gas production show a steady declining trend of EROI (energy return on investment) due to the depletion of shallow-buried coal resources and conventional oil and gas resources, which is generally consistent with the approaching peaks of physical production of fossil fuels. The peaks of fossil fuels production, coupled with the decline in EROI ratios, are likely to challenge the sustainable development of Chinese society unless new abundant energy resources with high EROI values can be found

    Aspect-ratio dependent oscillatory thermocapillary convection in the floating half zone

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    The dependency of the critical Marangoni number on the geometrical aspect ratio of the floating half zone is essential to predict the onset of oscillatory thermocapillary convection. The experimental studies in the microgravity conditions on floating half zones of several centimeters in diameter have predicted that the critical Marangoni number increases with the increasing aspect ratio, and the terrestrial experimental studies have predicted the contradictory conclusion for floating half zones of several millimeters in diameter. In the present work, terrestrial experimental studies were conducted on the floating half zones of 5 Centistokes (cSt) silicon oil and 10 cSt silicon oil. The experimental results show that the critical Marangoni number generally increases with the increasing aspect ratio of the floating half zone and then decreases. Moreover, a further increase of the critical Marangoni number with the increasing aspect ratio occurs for the slender floating half zones

    Interaction between the atmospheric boundary layer and a standalone wind turbine in Gansu-Part I: Field measurement

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    Experiments and numerical simulations of the wake field behind a horizontal-axis wind turbine are carried out to investigate the interaction between the atmospheric boundary layer and a stand-alone wind turbine. The tested wind turbine (33 kW) has a rotor diameter of 14.8 m and hub height of 15.4 m. An anti-icing digital Sonic wind meter, an atmospheric pressure sensor, and a temperature and humidity sensor are installed in the upstream wind measurement mast. Wake velocity is measured by three US CSAT3 ultrasonic anemometers. To reflect the characteristics of the whole flow field, numerical simulations are performed through large eddy simulation (LES) and with the actuator line model. The experimental results show that the axial velocity deficit rate ranges from 32.18% to 63.22% at the three measuring points. Meanwhile, the time-frequency characteristics of the axial velocities at the left and right measuring points are different. Moreover, the average axial and lateral velocity deficit of the right measuring point is greater than that of the left measuring point. The turbulent kinetic energy (TKE) at the middle and right measuring points exhibit a periodic variation, and the vortex sheet-pass frequency is mostly similar to the rotational frequency of the rotor. However, this feature is not obvious for the left measuring point. Meanwhile, the power spectra of the vertical velocity fluctuation show the slope of -1, and those of lateral and axial velocity fluctuations show slopes of -1 and -5/3, respectively. However, the inertial subranges of axial velocity fluctuation at the left, middle, and right measuring points occur at 4, 7, and 7 Hz, respectively. The above conclusion fully illustrates the asymmetry of the left and right measuring points. The experimental data and numerical simulation results collectively indicate that the wake is deflected to the right under the influence of lateral force. Therefore, wake asymmetry can be mainly attributed to the lateral force exerted by the wind turbine on the fluid.</p

    The effects of environmental disturbances on tumor growth

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    In this study, the analytic expressions of the steady probability distribution of tumor cells were established based on the steady state solution to the corresponding Fokker-Planck equation. Then, the effects of two uncorrelated white noises on tumor cell growth were investigated. It was found that the predation rate plays the main role in determining whether or not the noise is favorable for tumor growth.Comment: 14 pages, 11 figures. Note: The paper will be published on volume 42 of the Brazilian Journal of Physic
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