Efficient RFID authentication scheme for supply chain applications

Radio Frequency Identification (RFID) technology has been widely used in supply chains to track and manage shipments. By tagging shipments with RFID tags, which can be remotely accessed by RFID readers, shipments can be identified and tracked in a supply chain. Security issues in RFID have been major concerns, since passive RFID tags have very weak computational power to support authentication. Sound authentication between tag and reader remains a challenging problem. In this paper, we provide a novel authentication scheme to protect tags from being tracked and identified by unauthorized readers and protect authorized readers against bogus tags. Our scheme can be applied to supply chain security. It also exhibits an additional feature that a supply chain can be dynamically updated

Analysis on the Performance of Server-less RFID Searching Protocol

Radio frequency identification (RFID) has spread into many fields. Its security and privacy has received more and more attention. Based on traditional authentication protocols, some other branches related to practical applications have been introduced including server-less authentication and searching protocols. The server-less searching protocol is extended from server-less authentication protocol and both of them are executedwithout the support from the backend servers. Through analyzing some proposed protocols, we found that the probabilistic tracking attack is one of the major threats on the serverless RFID security protocols. The probability of being tracked and the cost on computation are related with the probability of the undesired tag’s response. Based on the analysis, a practical conclusion is given which can be used in most of the server-less RFID systems

Transition of stoichiometricSr2VO3FeAs to a superconducting state at 37.2 K

The superconductor Sr4V2O6Fe2As2 with transition temperature at 37.2 K has been fabricated. It has a layered structure with the space group of p4/nmm, and with the lattice constants a = 3.9296Aand c = 15.6732A. The observed large diamagnetization signal and zero-resistance demonstrated the bulk superconductivity. The broadening of resistive transition was measured under different magnetic fields leading to the discovery of a rather high upper critical field. The results also suggest a large vortex liquid region which reflects high anisotropy of the system. The Hall effect measurements revealed dominantly electron-like charge carriers in this material. The superconductivity in the present system may be induced by oxygen deficiency or the multiple valence states of vanadium.Comment: 5 pages, 4 figure

Superconductivity at 15.6 K in Calcium-doped Tb_{1-x}Ca_xFeAsO: the structure requirement for achieving superconductivity in the hole-doped 1111 phase

Superconductivity at about 15.6 K was achieved in Tb_{1-x}Ca_xFeAsO by partially substituting Tb^{3+} with Ca^{2+} in the nominal doping region x = 0.40 \sim 0.50. A detailed investigation was carried out in a typical sample with doping level of x = 0.44. The upper critical field of this sample was estimated to be 77 Tesla from the magnetic field dependent resistivity data. The domination of hole-like charge carriers in the low-temperature region was confirmed by Hall effect measurements. The comparison between the calcium-doped sample Pr_{1-x}Ca_xFeAsO (non-superconductive) and the Strontium-doped sample Pr_{1-x}Sr_xFeAsO (superconductive) suggests that a lager ion radius of the doped alkaline-earth element compared with that of the rare-earth element may be a necessary requirement for achieving superconductivity in the hole-doped 1111 phase.Comment: 7 pages, 7 figure

Ubrzano toplinsko starenje nitril-butadienskog kaučuka s dodanim grafenom

In this paper, the thermal ageing of nitrile-butadiene rubber (NBR) reinforced with different graphene (GE) concentrations has been investigated. NBR and NBR-GE composites were exposed to an accelerated thermal ageing environment produced by an air-circulating oven for seven days. The mechanical properties, chemical changes, and thermal stability of ageing samples and neat samples were evaluated. The results showed that the surface damage of NBR was severe and inhomogeneous, and the degree of ageing was most serious on the edge region of the voids, but NBR-GE composites were changed slightly before and after ageing. The tensile strength increased with the increase of GE concentration, up to a maximum value, and decreased with further increases in GE concentration. The GE embedded crosslinked network limited the segment movement of chains in the stretch direction and played a role in the composites properties, and the GE sheets (contained the functional groups of −OH, −C=O and C=C) after ageing. This behaviour may indicate greater interface adhesion between the GE and NBR. In addition, results obtained by thermogravimetric analysis (TGA) indicated that the thermal stability of NBR significantly changed with accelerated thermal ageing environment, but with addition of a certain amount of GE to NBR, the thermal stability of NBR could be improved. The NBR/GE composites exhibited good comprehensive performance with a mass fraction of GE of 10 %. Before and after the thermal ageing, the failure mechanism of NBR-GE composites appeared intergranular and ductile fracture, respectively. This work is licensed under a Creative Commons Attribution 4.0 International License.U ovom radu istraživano je toplinsko starenje nitril-butadienskog kaučuka (NBR) uz različite udjele grafena (GE). Kompoziti NBR i NBR-GE bili su izloženi ubrzanom toplinskom starenju koje je proizvodila zračna cirkulacijska pećnica tijekom sedam dana. Ispitivana su mehanička svojstva, kemijske promjene i toplinska stabilnost uzoraka starenja i čistih uzoraka. Rezultati su pokazali veliko i nehomogeno površinsko oštećenje NBR-a. Stupanj starenja bio je najozbiljniji na rubnom dijelu praznina, dok su se kompoziti NBR-GE prije i poslije starenja neznatno promijenili. S povećanjem koncentracije GE, vlačna čvrstoća se uvećala do maksimalne vrijednosti i smanjila s daljnjim povećanjem koncentracije GE. Ugrađena GE mreža ograničila je kretanje lanaca u smjeru rastezanja i odigrala ulogu u svojstvima kompozita i slojevima GE (sadržavali su funkcionalne skupine −OH, −C=O i C=C) nakon starenja. Ta pojava može ukazivati na veću međupovršinsku adheziju GE i NBR. Dodatno, rezultati dobiveni termogravimetrijskom analizom (TGA) pokazuju da se termička stabilnost NBR-a znatno promijenila s ubrzanim uvjetima toplinskog starenja, ali uz dodatak određene količine GE u NBR, može se poboljšati toplinska stabilnost NBR-a. Kompoziti NBR-GE pokazali su dobra sveobuhvatna svojstva s masenim udjelom GE od 10 %. Prije i nakon toplinskog starenja, mehanizam kvara kompozita NBR-GE pokazao je intergranularne i duktilne prijelome. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Two-parameter estimation with three-mode NOON state in a symmetric three-well

We propose a theoretical scheme to realize two-parameter estimation via a Bose-Einstein condensates confined in a symmetric triple-well. The three-mode NOON state is prepared adiabatically as the initial state. Two phase differences between the wells are two parameters to be estimated. With the help of classical and quantum Fisher information, we study the sensitivity of the triple-well on estimating two phase parameters simultaneously. The result shows that the precision of simultaneous estimation of two parameters in a triple-well system can reach the Heisenberg scaling

(Sr_3Sc_2O_5)Fe_2As_2 as a possible parent compound for FeAs-based superconductors

A new compound with the FeAs-layers, namely (Sr_3Sc_2O_5)Fe_2As_2 (abbreviated as FeAs-32522), was successfully fabricated. It has a layered structure with the space group of I4/mmm, and with the lattice constants a = 4.069 $\AA$ and c = 26.876 $\AA$. The in-plane Fe ions construct a square lattice which is close to that of other FeAs-based superconductors, such as REFeAsO (RE = rare earth elements) and (Ba,Sr)Fe_2As_2. However the inter FeAs-layer spacing in the new compound is greatly enlarged. The temperature dependence of resistivity exhibits a weak upturn in the low temperature region, but a metallic behavior was observed above about 60 K. The magnetic susceptibility shows also a non-monotonic behavior. Interestingly, the well-known resistivity anomaly which was discovered in all other parent compounds, such as REFeAsO, (Ba,Sr)Fe_2As_2 and (Sr,Ca,Eu)FeAsF and associated with the Spin-Density-Wave (SDW)/structural transition has not been found in the new system either on the resistivity data or the magnetization data. This could be induced by the large spacing distance between the FeAs-planes, therefore the antiferromagnetic correlation between the moments of Fe ions in neighboring FeAs-layers cannot be established. Alternatively it can also be attributed to the self-doping effect between Fe and Sc ions. The Hall coefficient R_H is negative but strongly temperature dependent in wide temperature region, which indicates the dominance of electrical conduction by electron-like charge carriers and probably a multi-band effect or a spin related scattering effect. It is found that the magnetoresistance cannot be described by the Kohler's rule, which gives further support to above arguments.Comment: 5 pages, 5 figures, some contents added, and one figure adde