Construction of spirocarbocycles via gold-catalyzed intramolecular dearomatization of naphthols.

A highly efficient, gold-catalyzed intramolecular dearomatization reaction of naphthols via 5-endo-dig cyclization is described. This facile and direct approach furnishes spirocarbocycles in excellent yields under mild conditions

Genus Gelastorhinus Brunner-Wattenwyl (Orthoptera: Acridoidea) in China with description of a new species

A new species of the genus Gelastorhinus is described from Liaoning, China. The new species closely resembles Gelastorhinus filatus (Walker, 1870). In addition, an identification key for the Chinese species of Gelastorhinus is presented

Review and key of East Palaearctic species of the genus Podismopsis Zubovsky (Orthoptera: Acridoidea) with description of a new species from China

In this paper, a list and key of all East Palaearctic Podismopsis species are presented. In addition, Podismopsis squamopennis sp. n. is described from the Small Northern Lake of Heilongjiang province in China. It mostly resembles P. gynaemorpha Ikonnov

Secure Mobile Agents in Electronic Commerce by Using Undetachable Signatures from Pairings

It is expect that mobile agents technology will bring significant benefits to electronic commerce. But security issues, especially threats from malicious hosts, become a great obstacle of widespread deployment of applications in electronic commerce based on mobile agents technology. Undetachable digital signature is a category of digital signatures to secure mobile agents against malicious hosts. An undetachable signature scheme by using encrypted functions from bilinear pairings was proposed in this paper. The security of this scheme base on the computational intractability of discrete logarithm problem and computational Diffe-Hellman problem on gap Diffle-Hellman group. Furthermore, the scheme satisfies all the requirements of a strong non-designated proxy signature i.e. verifiability, strong unforgeability, strong identifiability, strong undeniability and preventions of misuse. An undetachable threshold signature scheme that enable the customer to provide n mobile agents with ‘shares’ of the undetachable signature function is also provided. It is able to provide more reliability than classical undetachable signatures

Analysis on deformation characteristics and energy dissipation of marble under different unloading rates

Ispitivanja oštećenja provodila su se na mramoru kod različitih brzina ograničenja tlaka pri rasterećenju da bi se dobila krivulja promjene energije cijeloga procesa deformacije i oštećenja. S povećanjem brzine rasterećenja, razlike vršnog naprezanja kod oštećenja mramora su se smanjile, razlike ograničenja tlaka su se povećale, omjeri prirasta ograničenja tlaka kod svakog naprezanja su bili manji, a deformacija volumena je bila osjetljivija na promjene ograničenja tlaka kod rasterećenja. Oštećenje kod rasterećenja nastalo je širenjem volumena, i što je veća bila brzina rasterećenja, lakše je dolazilo do oštećenja stijene. S porastom brzine rasterećenja, prirast ukupne apsorbirane energije, prirast elastične energije i prirast disipacije energije smanjili su se u stadiju rasterećenja mramora. Prirast rasipanja energije u postupku rasterećenja bio je pet puta veći od onoga u postupku opterećenja dok je prirast elastične energije pokrivao svega 10 % ukupne akumulirane energije. Postupak rasterećenja pokazao je porast rasipanja energije, a stanje geo-naprezanja stijenske mase odredilo je nivo energije otpuštene u oštećenju.Failure tests were conducted on marble under different unloading confining pressure rates to obtain the energy change curve of whole-process deformation and failure. With increasing unloading rate, the peak stress differences in marble failure were reduced, confining pressure differences in failure increased, the increment ratios of each stress confining pressure were smaller, and the volume deformation was more sensitive to changes in unloading confining pressure. Unloading failure was caused by volume expansion, and the greater the unloading rate was, the easier the rock failure was. With the increasing unloading rate, total absorbed energy increment, elastic energy increment and dissipated energy increment were reduced in the unloading stage of marble. The dissipated energy increment in the unloading process was more than five times that in the loading process, while the elastic energy increment only accounted for 10 % of total stored energy. The unloading process showed increasing dissipated energy, and the geo-stress state of the engineering rock mass determined the level of energy released in failure