Adsorption of unsaturated hydrocarbon moieties on H:Si(111) by Grignard reaction

Grafting of unsaturated hydrocarbon moieties (-CH(2)-CH=CH(2), -CH=CH(2), -CH(2)-CH=CH-CH(3), and -CCH) by a C-Si covalent bond was attempted by the Grignard reaction on hydrogen-terminated Si(111) in tetrahydrofuran solutions. The product adsorbates were monitored by vibrational methods of high-resolution electron energy loss spectroscopy and multiple internal infrared reflection absorption spectroscopy, as well as Auger electron spectroscopy. The temperature and the period of reaction were adjusted so as to preserve the unsaturated carbon-carbon bonds. The -CH(2)-CH=CH(2) group was introduced by a mild reaction condition, with the reservation of the C=C double bond confirmed. The unsaturated bonds in -CH(2)-CH=CH-CH(3) and -CCH were also reserved. Only in the case of -CH=CH(2) was the reservation of the C=C double bond not realized. Unsaturated hydrocarbon moieties are applicable for further organic modification to introduce functional groups, and are prospective materials in nanofabrication and biological application on silicon wafer surfaces.     

On the (in)efficiency of non-interactive secure multiparty computation

Secure multi-party computation (MPC) enables multiple players to cooperatively evaluate various functions in the presence of adversaries. In this paper, we consider non-interactive MPC (NIMPC) against honest-but-curious adversaries in the information-theoretic setting, which was introduced by Beimel et al. at CRYPTO 2014. Their main focus is to realize stronger security while completely avoiding interaction, and succeeded to show that every function admits a fully robust NIMPC protocol. In this paper, we further develop the study of NIMPC. We first present a simple lower bound on the communication complexity derived from the correctness requirement of NIMPC. Secondly, we present an efficient NIMPC protocol for indicator functions, which is an important building block of NIMPC protocols. An NIMPC protocol for arbitrary functions is also constructed from the proposed NIMPC for indicator functions by using the generic compiler introduced by Beimel et al. in CRYPTO 2014. The communication complexities of NIMPC protocols presented in this paper are much more efficient than the previous ones. In fact, the gap between the lower and upper bounds of the communication complexity is reduced from exponential in the input length to quadratic. Finally, we show some improvements on the efficiency in the so-called offline-online model. Specifically, for some sets of functions, the exponential amount of offline communication reduces the online communication to almost optimum amount in the standard model.     

Scale effect of spherical projectiles for stabilization of oblique detonation waves

Shock Waves - Oblique detonation waves (ODWs) were stabilized by launching a spherical projectile with 1.2–1.4 times the Chapman–Jouguet (C–J) velocity into detonable mixtures at...     

A Note on the Local Time of Fractional Brownian Motion

Asymptotic behavior of the local time at the origin of q-dimensional fractional Brownian motion is considered when the index approaches the critical value 1/q. It is proved that, under a suitable (temporally inhomogeneous) normalization, it converges in law to the inverse of an extremal process which appears in the extreme value theory.     

The aminomethylation of electron-rich aromatics with an N-silyl-N,O-acetal catalyzed by a metal triflate-TMSCl system: facile synthesis of aromatic primary amines, 1-aryl-trichloroethylamines

The copper(II) triflate- and hafnium(IV) triflate-catalyzed aminomethylation of indole (2) with an N-silyl-N,O-acetal 1 containing a trichloromethyl group provides the primary amine derivative (3a) in modest yield. When 1 equiv of trimethylchlorosilane (TMSCl) was added to the reaction mixture, the reaction proceeded smoothly, and the yield of 3a was dramatically improved (>90%). The use of this catalytic system permitted the introduction of an aminomethyl group onto indoles 2a-h bearing a variety of functional groups, which appears to deactivate the Lewis acid, in 52-92% yields. Hf(OTf)4-doped TMSCl catalyzed the successful aminomethylation of various electron-rich aromatic compounds 4a-j to produce 1-aryl-trichloroethylamine derivatives 5a-j.     

Asymmetric autocatalysis induced by chiral hydrocarbon [2.2]paracyclophanes

Chiral hydrocarbon [2.2]paracyclophanes act as chiral initiators in asymmetric autocatalysis in the addition of diisopropylzinc to pyrimidine-5-carbaldehyde and give highly enantiomerically enriched 5-pyrimidyl alkanol with a reversed sense of the enantioselectivity to that of other [2.2]paracyclophanes with heteroatoms.