Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract： As phase change heat storage material (PCM), composites of paraffin/expanded graphite of different particle sizes (DPS-EG) were prepared by melt blending method, which were then characterized by means of XRD, FT- IR, SEM, DSC and LFA. The effect of mass fraction of DPS-EG on performance of the composite PCM was studied. Results show that the thermal diffusivity of the composite PCM increased first and then decreased with the increasing mass fraction of small particle sized EG. When the ratio of mass fraction for large sized ones to the small ones of the DPS-EG was 9:1, paraffin may be allowed to fill fully into the free space of the mosaic structure of DPS-EG. The thermal diffusivity of the composite PCM was up to 1.964�10-6 m2/s, 22 times higher than that of pure paraffin, while its latent heat was 144.2 J/g.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-12-13 Cooperative journals: 《计算机应用研究》
Abstract： Attribute-based encryption algorithm has the characteristics as flexibility, fine-grained and high security. This paper introduces an improved attribute-based outsourced encryption algorithm based on secure data access control attribute-based encryption, to reduce the resources consumed by computation, which outsources the complex bilinear pairings in the encryption computing to the fog node to reduce the user's computation overhead. By simplifying the system parameters, we reduce the random number generated by attribute authority for every attribute to shorten the length of ciphertext and the key, as well as the storage cost of the system. And the security proof of the scheme is given in the last part of this paper.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-11-29 Cooperative journals: 《计算机应用研究》
Abstract： Aiming at the problem of low computational efficiency of the current certificateless aggregation signcryption (CLASC) scheme, this paper proposed an aggregate signcryption scheme which is suitable for the Internet of things without bilinear pairings. Compared with the current best scheme[15], the efficiency of the scheme is increased by nearly 6 times. The scheme only needs (2n+1) times of dot multiplication operation in the aggregate signcryption stage, and (5n+1) times of dot multiplication operation in the aggregate unsigncryption stage. Based on the discrete logarithm problem, the scheme satisfied confidentiality and the unforgeability under the random oracle model. In the aggregate signcryption verification phase, there is no need to provide the third party’s secret information, so the scheme satisfies public verifiability. Finally, it also pointed out that the scheme can achieve higher security at lower computation speed and is more suitable for Internet of things.
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