We present the first experimental evidence supported by simulations of kinetic effects launched in the interpenetration layer between the laser-driven hohlraum plasma bubbles and the corona plasma of ...the compressed pellet at the Shenguang-III prototype laser facility. Solid plastic capsules were coated with carbon-deuterium layers; as the implosion neutron yield is quenched, DD fusion yield from the corona plasma provides a direct measure of the kinetic effects inside the hohlraum. An anomalous large energy spread of the DD neutron signal (∼282 keV) and anomalous scaling of the neutron yield with the thickness of the carbon-deuterium layers cannot be explained by the hydrodynamic mechanisms. Instead, these results can be attributed to kinetic shocks that arise in the hohlraum-wall-ablator interpenetration region, which result in efficient acceleration of the deuterons (∼28.8 J, 0.45% of the total input laser energy). These studies provide novel insight into the interactions and dynamics of a vacuum hohlraum and near-vacuum hohlraum.
•The effect of geometric parameters on flow and heat transfer characteristics was investigated for supercritical methane flow.•The heat transfer performance factor (TPF) was introduced when ...optimizing the structure of PCHE.•Response Surface Method (RSM) was utilized to find a compromise between flow and heat transfer performance.
Printed circuit heat exchanger (PCHE) is a compact plate heat exchanger that etches microchannels on plates by chemical etching method and exploits bonding force between the atoms to achieve diffusion bonding. It has the promising applications in the fields of floating liquefied natural gas, nuclear reactor, hydrogen energy, etc. The influence of structural parameters on flow and heat transfer characteristics in a Zigzag-channel PCHE was investigated using supercritical methane as flow media. Three-dimensional turbulent steady numerical method was determined and verified through the SST k-ω turbulent model in FLUENT platform. The influence mechanism of structural parameters on flow and heat transfer characteristics was analyzed from temperature distribution, turbulent dissipation rate, vortex vector, turbulent intensity and helicity. The results indicated that the worse flow and better heat transfer performance exhibited under the condition with small channel diameter, small pitch and large bending angle. Meanwhile, the optimization analysis was also conducted though the coupling consideration of flow and heat transfer performances of PCHE using thermal performance factor (TPF). The optimum channel was obtained with the diameter, channel pitch, and bending angle of 1.427 mm, 24.6 mm, and 15° respectively, in scope of this study. The optimum structure parameters obtained herein will be instructive in the design of PCHE.
In recent years, the leader-following consensus problem for multiple uncertain Euler-Lagrange systems has been studied under some restrictive assumptions on the network topology. In this paper, we ...further study the same problem under switching network topology. We propose a distributed adaptive control law that can solve the problem under a switching network satisfying jointly connected condition. Under this condition, our results do not require the network to be undirected and allow the network to be disconnected at any time instant. Moreover, by introducing an exosystem to generate various reference signals, our control law can handle a class of reference signals such as sinusoidal signals with arbitrary amplitudes and initial phases or ramp signals with arbitrary slopes.
POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) is a multisystem disorder with a good long-term prognosis. In its dozens of clinical features, ...those with independent prognostic value are still not well characterized. We retrospectively included 362 patients with newly diagnosed POEMS syndrome at our institute from 2000 to 2015. On the basis of a randomized sample splitting, we first identified four baseline clinical variables, including age >50 years (hazards ratio (HR) 4.07, 95% confidence interval (CI) 1.41-11.76, P=0.009), pulmonary hypertension (HR 3.99, 95% CI 1.44-11.04, P=0.008), pleural effusion (HR 3.81, 95% CI 1.23-11.79, P=0.02) and estimated glomerular filtration rate <30 ml/min/1.73 m
(HR 8.25, 95% CI 2.18-31.25, P=0.002), associated with inferior overall survival in the derivation cohort, with the use of multivariate Cox regression model. These factors were incorporated together to develop a prognostic nomogram. Concordance index calculation (0.727, 95% CI 0.601-0.853, P=0.018) and calibration curve plotting demonstrated its significant predictive and discriminatory capacity in the validation cohort. This nomogram could be a useful and convenient tool in clinical practice to evaluate individualized prognosis in patients with newly diagnosed POEMS syndrome.
Highlights • Two regimens as the first line treatment in adult LCH were compared. • Two regimens for the treatment of adult SS-m or MS LCH showed similar efficacy. • Treatment with two regimens was ...associated with a high recurrence rate.
Mechanical behaviors of transformation induced plasticity (TRIP) steels largely depend on the amount and stability of austenite. In this investigation, a large volume fraction of austenite (>65%) was ...produced in a hot-rolled Fe-11Mn-3.8Al-0.18C TRIP steel by solution treatment in the temperature range of 750–800°C for 1h. The hot-rolled alloy exhibited an excellent combination of total elongation of 35–40% and ultimate tensile strength of 880–1100MPa and this was found to have a similar or higher level of tensile properties compared with other TRIP steels. In the meantime, less cold-rolling work or annealing time was required in the present work. The outstanding properties of the experimental steel were mainly attributed to the enhanced TRIP effect due to the large fraction of austenite. It is shown that the morphology played a more significant role than orientation in the stability of austenite.
ABSTRACT
The observation of the transient sky through a multitude of astrophysical messengers has led to several scientific breakthroughs in the last two decades, thanks to the fast evolution of the ...observational techniques and strategies employed by the astronomers. Now, it requires to be able to coordinate multiwavelength and multimessenger follow-up campaigns with instruments both in space and on ground jointly capable of scanning a large fraction of the sky with a high-imaging cadency and duty cycle. In the optical domain, the key challenge of the wide field-of-view telescopes covering tens to hundreds of square degrees is to deal with the detection, identification, and classification of hundreds to thousands of optical transient (OT) candidates every night in a reasonable amount of time. In the last decade, new automated tools based on machine learning approaches have been developed to perform those tasks with a low computing time and a high classification efficiency. In this paper, we present an efficient classification method using convolutional neural networks (CNNs) to discard many common types of bogus falsely detected in astrophysical images in the optical domain. We designed this tool to improve the performances of the OT detection pipeline of the Ground Wide field Angle Cameras (GWAC) telescopes, a network of robotic telescopes aiming at monitoring the OT sky down to R = 16 with a 15 s imaging cadency. We applied our trained CNN classifier on a sample of 1472 GWAC OT candidates detected by the real-time detection pipeline.
As the tidal wave propagates into an estuary, the tidally averaged water level tends to rise in landward direction due to the density difference between saline and fresh water and the asymmetry of ...the friction. The effect of friction on the residual slope is even more remarkable when accounting for fresh water discharge. In this study, we investigate the influence of river discharge on tidal wave propagation in the Yangtze estuary with specific attention to residual water level slope. This is done by using a one-dimensional analytical model for tidal hydrodynamics accounting for the residual water level. We demonstrate the importance of the residual slope on tidal dynamics and use it to improve the prediction of the tidal propagation in estuaries (i.e. tidal damping, velocity amplitude, wave celerity and phase lag), especially when the influence of river discharge is significant. Finally, we develop a new inverse analytical approach for estimating fresh water discharge on the basis of tidal water level observations along the estuary, which can be used as a tool to obtain information on the river discharge that is otherwise difficult to measure in the tidal region.
Consideration of transient stability constraints in optimal power flow (OPF) problems is increasingly important because modern power systems tend to operate closer to stability boundaries due to the ...rapid increase of electricity demand and the deregulation of electricity markets. Transient stability constrained OPF (TSCOPF) is however a nonlinear optimization problem with both algebraic and differential equations, which is difficult to be solved even for small power systems. This paper develops a robust and efficient method for solving TSCOPF problems based on differential evolution (DE), which is a new branch of evolutionary algorithms with strong ability in searching global optimal solutions of highly nonlinear and nonconvex problems. Due to the flexible properties of DE mechanism, the hybrid method for transient stability assessment, which combines time-domain simulation and transient energy function method, can be employed in DE so that the detailed dynamic models of the system can be incorporated. To reduce the computational burden, several strategies are proposed for the initialization, assessment and selection of solution individuals in evolution process of DE. Numerical tests on the WSCC three-generator, nine-bus system and New England ten-generator, 39-bus system have demonstrated the robustness and effectiveness of the proposed approach. Finally, in order to deal with the large-scale system and speed up the computation, DE is parallelized and implemented on a Beowulf PC-cluster. The effectiveness of the parallel DE approach is demonstrated by simulations on the 17-generator, 162-bus system.
PDF
