Asymmetric cycloaddition reactions represent a powerful strategy for building up complex molecular architectures, especially those with medium-sized rings. Herein, we disclose a highly diastereo- and enantioselective cycloaddition strategy that involves...

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Fingerprint-protected Universal Serial Bus (USB) drives have seen increasing deployment recently to protect mobile data. Compared to regular USB drives, a fingerprint-protected USB drive has an integrated optical scanner and a private partition/drive (for example, drive G: on MS Windows), which is not accessible before a successful fingerprint authentication.This paper studies the security of a representative fingerprintprotected USB drive called AliceFDrive. Our results are twofold. First, through black-box reverse engineering and manipulation of binary code in a DLL, we bypassed AliceFDrive's fingerprint authentication and accessed the private drive without actually presenting a valid fingerprint. This authentication bypass is a class attack in that the modified DLL can be distributed to any naive users to bypass AliceFDrive's fingerprint authentication.Second, in our security analysis of AliceFDrive, we developed a program to automatically recover fingerprint reference templates from AliceFDrive, which may make AliceFDrive worse than a regular USB drive: when Alice loses her fingerprint-protected USB drive, she does not only lose her data, she also loses her good-quality fingerprints, which are hard to recover as Alice's fingerprints do not change much over a long period of time.

Harmony search algorithm with differential evolution based control parameter co-evolution and its application in chemical process dynamic optimization FAN Qin-qin(范勤勤), WANG Xun-hua(王循华), YAN Xue-feng(颜学峰)Abstract: A modified harmony search algorithm with co-evolutional control parameters (DEHS), applied through differential evolution optimization, is proposed. In DEHS, two control parameters, i.e., harmony memory considering rate and pitch adjusting rate, are encoded as a symbiotic individual of an original individual (i.e., harmony vector). Harmony search operators are applied to evolving the original population. DE is applied to co-evolving the symbiotic population based on feedback information from the original population. Thus, with the evolution of the original population in DEHS, the symbiotic population is dynamically and self-adaptively adjusted, and real-time optimum control parameters are obtained. The proposed DEHS algorithm has been applied to various benchmark functions and two typical dynamic optimization problems. The experimental results show that the performance of the proposed algorithm is better than that of other HS variants. Satisfactory results are obtained in the application.

By using purified divinylbenzene (DVB, 98.8%) or technical DVB (79.3%), the hydrophobic, but water-wettable or swellable porous copolymer resins based on DVB and acrylonitrile (AN) could be prepared with a wide range of pore structures under certain conditions. The specific surface area for the resulting AN/DVB resin, with an AN/DVB ratio of 40/60 (by mole), could reach a value of 704 m 2 /g, while such a resin is still water wettable or swellable by direct contact with water. The adsorption behavior of the AN/DVB resins was investigated by focusing on the comparison between the resins with and without prewetting, using caffeine and phenol as model adsorbates.Adsorption behavior of the AN/DVB resins, without prewetting, correlates well with the wetting ability of the resins in water, suggesting that a well water-wettable hydrophobic porous AN/DVB resin could be directly applied, in a dry state, to the adsorption in an aqueous medium, almost without diminishing the ability of the resin to adsorb the solutes.