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The emerging Software-Defined Networking (SDN) is being adopted by data centers and cloud service providers to enable flexible control. Meanwhile, the current SDN design brings new vulnerabilities. In this paper, we explore a stealthy attack that uses a minimum rate of attack packets to disrupt SDN data plane. To achieve this, we propose the LOFT attack that computes the lower bound of attack rate to overflow flow tables based on the inferred network configurations. Particularly, each attack packet always triggers or maintains consumption of one flow rule. LOFT can ensure the attack effect under various network configurations while reducing the possibility of being captured. We demonstrate its feasibility and effectiveness in a real SDN testbed consisting of commercial hardware switches. The experimental results show that LOFT incurs significant network performance degradation and potential network DoS at an attack rate of only tens of Kbps. To defeat the attack, we develop a data-to-control plane collaborative defense system named LOFTGuard, which is lightweight and transparent to SDN applications. Evaluations show that LOFTGuard effectively protects SDN against the attack and introduces a small overhead.

The distance dependence of localized surface plasmon (LSP)-coupled Förster resonance energy transfer (FRET) between Si quantum dots (QDs) is experimentally and theoretically investigated utilizing core–shell nanostructures. The dependence of the energy transfer efficiency, rate, and characteristic distance, as well as the enhancement of the acceptor emission, on the shell thickness is examined. Compared to the structure without assistance of LSP from silver nanoparticles (Ag NPs), the FRET rate is enhanced by a factor of 15, and the Förster radius increases by 50% as a result of plasmon-coupling to the Si QDs and the FRET-assisted exciton transfer from the donors to the acceptors. The potential to tune the characteristic energy transfer distance has implications for applications in nanophotonic devices or sensors.

A flexible composite phase change material (FCPCM) reduces thermal contact resistance in battery thermal management systems (BTMSs), thereby improving heat transfer efficiency. However, its high electrical and low thermal conductivity hinders its application to cooling lithium-ion batteries. Herein, a type of FCPCM with well-retained flexibility as well as high electrical insulation and thermal conductivity is prepared by mixing paraffin (PA), styrene ethylene butylene styrene (SEBS), and hexagonal boron nitride (h-BN). The chemical, thermophysical, and mechanical properties, as well as the physical structure of the FCPCM are analyzed. The components (PA/SEBS/BN) show good physicochemical compatibility without chemically reacting. The shore hardness of the proposed FCPCM decreases from 80 to 9 HA as the temperature increases from 20 to 80 °C, and it can be easily stretched or bended beyond the melting point of PA. Moreover, this composite possesses large latent heat (127.8 J/g), high thermal conductivity (2.7 W/(m·K)), sufficient volume resistivity (20,106 Ω·m), and suitable phase change temperature (41.1 °C). With such exceptional qualities, it shows outstanding applicability and cooling performance in cylindrical and prismatic batteries. Temperature and temperature difference of the prismatic battery pack can be restrained below 45 °C and 4 °C, even at a high discharge rate of 6 C and an ambient temperature of 38 °C.

When working in a high temperature environment, people need to wear special clothing to avoid burns. The special clothing is usually composed of three layers of fabric materials, which are referred to as layers I, II and III. Layer I is in contact with the external environment directly. And there is also a gap between the layer III and the skin. We considered this gap as the layer IV. Firstly, it is assumed that heat balance exists between the air layer and the I layer, and between the IV layer and the dummy skin respectively. According to the experimental data of the outer skin temperature of the dummy and the principle of heat transfer, the heat exchange coefficient between the IV layer and the outer side of the skin is 0.0047. Using the heat balance relationship, the inner wall temperature of layer I is deduced, and the heat exchange coefficient between the air and the layer I is 0.0049. Secondly, the boundary conditions of the heat conduction model are obtained based on these heat exchange coefficients. And the one-dimensional heat conduction model of this special clothing is established. Since the medium of each layer of the special clothing is different, the diffusion coefficient of the equation is a piece-wise function. Combined the boundary conditions, we uses the implicit algorithm to obtain the discrete difference equations and ensure the stability of the numerical format. Finally, the temperature values of different space-time distributions are obtained.