Synthesis and characterization of carbon-coated Li0.5Ni0.25TiOPO4 anode material

Li_0.5Ni_0.25TiOPO₄/C composite was synthesized by the co-precipitation method using polyethylene glycol as carbon source. X-ray diffraction study showed that the as-prepared material crystallizes in the monoclinic system (S.G. P2₁/c). This 3D structure exhibits an open framework favourable to intercalation reactions. The morphology and the microstructure characterisation was performed by scanning electron microscopy (SEM). Small particles (∼1 μm) coated by carbon were observed. Raman study confirms the presence of carbon graphite in the Li_0.5Ni_0.25TiOPO₄/C composite. Cyclic voltammetry (CV) and charge-discharge galvanostatic cycling were used to characterize its electrochemical properties. The Li_0.5Ni_0.25TiOPO₄/C composite exhibits excellent electrochemical performances with good capacity retention for 50 cycles. Approximately 200 mAh/g could be reached at C, C/2, C/5 and C/20 rates in the 0.5-3 V potential range. These results clearly evidenced the positive effect of the carbon coating on the electrochemical properties of the studied phosphate.     

Cryptanalysis of an identity‐based authenticated key exchange protocol

Authenticated key exchange protocols represent an important cryptographic mechanism that enables several parties to communicate securely over an open network. Elashry, Mu, and Susilo proposed an identity‐based authenticated key exchange (IBAKE) protocol where different parties establish secure communication by means of their public identities.The authors also introduced a new security notion for IBAKE protocols called resiliency, that is, if the secret shared key is compromised, the entities can generate another shared secret key without establishing a new session between them. They then claimed that their IBAKE protocol satisfies this security notion. We analyze the security of their protocol and prove that it has a major security flaw, which renders it insecure against an impersonation attack. We also disprove the resiliency property of their scheme by proposing an attack where an adversary can compute any shared secret key if just one secret bit is leaked.     

Construction of cyclic codes over \mathbb F _2+u\mathbb F _2 for DNA computing

We construct codes over the ring $\mathbb F _2+u\mathbb F _2$ with $u^2=0$ for use in DNA computing applications. The codes obtained satisfy the reverse complement constraint, the $GC$ content constraint, and avoid the secondary structure. They are derived from cyclic reverse-complement codes over the ring $\mathbb F _2+u\mathbb F _2$ . We also construct an infinite family of BCH DNA codes.     

A New variant of the McEliece cryptosystem based on the Smith form of convolutional codes

In this article, the authors propose a new version of the McEliece cryptosystem based on the Smith form of convolutional codes. They use the Smith form to hide a part of the code in the public matrix, and they leave the other part secret. The secret part will then be used for decryption. They hide this part by multiplying it on the left by a random matrix, and they add a random matrix which has a few conditions. Their scheme has a small public key size compared to the original McEliece scheme and resists the unique decoding attack against convolutional structure presented at the conference PQCrypto 2013 by Landais and Tillich. Further, the exhaustive search attack is infeasible on their system.     

半沙漠地区中的生态住宅

项目地点:摩洛哥伊尔富德项目类型:建筑(住宅)开工日期:2006年元月该项目获2005年豪瑞可持续建筑大奖赛非洲中东地区提名奖     

Robust fault-tolerant control for discrete-time switched systems with time delays

This study outlines the problem of active fault-tolerant control for delayed discrete-time switched systems. Using switched proportional-integral observer and multiple Lyapunov-Krasovski function, less conservative sufficient conditions are established to design a robust fault estimation (FE) algorithm via linear matrix inequality form. Afterward, a fault-tolerant performance is realized based on this fast and exact FE information to compensate the effect of actuator fault while stabilizing the closed-loop system. The efficiency of the proposed strategy is proved through simulation examples and comparison results.     

The Use of the Golden Section in the Great Mosque at Kairouan

The geometrical analysis conducted reveals very clearly a consistent application of the golden section. The geometric technique of construction of the golden section seems to have determined the major decisions of the spatial organisation. The golden section appears repeatedly in some part of the building measurements. It is found in the overall proportion of the plan and in the dimensioning of the prayer space, the court and the minaret. The existence of the golden section in some parts of Kairouan mosque indicates that the elements designed and generated with this principle may have been realised at the same period. This suggests and opens the possibility for further inquiry into the dating of the transformations that took place in this mosque. Authors Kenza Boussora and Said Mazouz examine earlier archaeological theories about the mosque, demonstrate the geometric constructions for the golden section, and apply these constructions to the plan of the mosque to test their hypothesis.     

Emerging applications of phase change materials: A concise review of recent advances

Phase change materials (PCMs) are used as latent heat thermal energy storage materials. The fields of application for PCMs are broad and diverse. Among these areas are thermal control of electronic components and thermal building regulations. These areas are used as heat and cold storage materials. The low thermal conductivity of PCMs is one of the significant and severe technological problems of PCMs. This paper presents a review of the latest works using PCMs in the thermal management of electronic components, buildings, and heat exchangers. Besides, it provides concise pieces of information on the classification of PCMs, their advantages, disadvantages, and thermal storage systems.