Gorodnitskii, A. M.
Brusilovskii, Yu. V.
Ivanenko, A. N.
Popov, K. V.
Shishkina, N. A.
The analysis of the magnetic survey data suggests the presence of a frontal zone of intense magnetic anomalies in a number of the Pacific island-arc systems. These zones with amplitudes of 100-300 nT are observed within the Kuril-Kamchatka and Aleutian island arc systems, in Southern and Central America, and Alaska. As demonstrated by the solution of the inverse problem and petromagnetic investigation of the rocks, these zones are presumably related to the serpentinite bodies which form as a result of the hydration of the upper mantle peridotites by the oceanic water penetrating through a system of cracks and fractures into the subducting slab at its bend. The rock magnetic studies show that magnetite is the main carrier of magnetization in these serpentinite bodies. Hydration of the subducting slab also causes hydration of the mantle rocks of the overriding plate with the formation of the magnetized serpentinite wedge. The decompaction of ultrabasic rocks under hydration is marked by a decrease in the gravity field and velocities of elastic waves. As the subducting plate loses water, it becomes embrittled and becomes the localization region for the epicenters of the strongest earthquakes. Magnetic survey can be used for revealing the potential sources of catastrophic earthquakes.
Sergeev, A. V.
Narkhov, E. D.
Ivanenko, A. N.
Brusilovskiy, Yu. V.
Milyukov, D. N.
Denisov, A. Yu.
Sapunov, V. A.
We tested the full-gradient magnetometer's system of two ortho oriented Overhauser with a GPS receiver in shallow water. Our investigations show that this is a promising layout prototype of magnetometer measuring complex, designed for high-precision 3D detecting and studying of underwater man-made objects. With such a system, and the existing set of techniques and software we can be able to reliably map and identify anomalies created by such objects, solving the problem of their locations within a small part of meter.
A novel method for conversion of N-arylhydrazides to N,N-diarylhydrazides via aerobic oxidation has been achieved. The aerobic reaction was performed using CuCl2 as a catalyst in NH3H2O-MeOH to give good yields under mild conditions. The mechanism of the reaction is also discussed.
Galt, Alexey
Kulshrestha, Amit
Singh, Anupam
Vdovin, Evgeny
In the paper, we consider images of finite simple projective special linear and unitary groups under power words. In particular, we show that, if G similar or equal to PSLn epsilon (q), then, for every power word of type x(M), there exist constants c and N such that vertical bar omega(G)vertical bar > c ln(n) vertical bar G vertical bar/n whenever vertical bar G vertical bar& > N.
Grond, J. J.
Woods, R. M.
Wadsley, J. W.
Couchman, H. M. P.
We present Tree-based REVerse Ray Tracing (TREVR), a general algorithm for computing the radiation field, including absorption, in astrophysical simulations. TREVR is designed to handle large numbers of sources and absorbers; it is based on a tree data structure and is thus suited to codes that use trees for their gravity or hydrodynamics solvers (e.g. adaptivemesh refinement). It achieves computational speed while maintaining a specified accuracy via controlled lowering of the resolution of both sources and rays from each source. TREVR computes the radiation field in order N log N-source time without absorption and order N log N(source)logN time with absorption. These scalings arise from merging sources of radiation according to an opening angle criterion and walking the tree structure to trace a ray to a depth that gives the chosen accuracy for absorption. The absorption-depth refinement criterion is unique to TREVR. We provide a suite of tests demonstrating the algorithm's ability to accurately compute fluxes, ionization fronts, and shadows.
In order to solve the problem of ambiguous acquisition of BOC signals caused by its property of multiple peaks, an unambiguous acquisition algorithm is proposed in this paper. The concept of sub quadratic correlation function and sub QBOC code are first defined in this letter by analyzing the autocorrelation and quadratic correlation of BOC(n,n). Then a new correlation function without multiple peaks can be obtained by a simple combination of sub quadratic correlation, which can be used to unambiguous acquisition for BOC(n,n). The theoretical analysis and simulation prove that the proposed algorithm not only can accomplish unambiguous acquisition but also have more effective de-ambiguity, higher capture sensitivity and higher peak to average power ratio compared to the classical BPSK-like, SPCP and ASPeCT algorithms.
German A(djective)-N(oun)-N(oun) compounds exhibit unexpected internal inflection. The main purpose of this paper is to account for the interesting fact that the adjective in German A-N-N compounds shows several options to inflect for case. It can either agree with the first noun, with the second noun, or with neither of them. A production-task experiment confirms the existence of all three patterns. This is an important result since from a theoretical perspective, agreement of the adjective with the second noun is unexpected because it seems to violate standard locality conditons. Our claim is that the semantic relation in A-N-N compounds is always represented correctly. As a consequence, the different observed inflection strategies are not due to different structures (contra Lawrenz in Deutsch als Fremdsprache 32(1):39-42, 1995). We rather argue that the observed diversity is a consequence of the order of syntactic operations that apply: In German A-N-N compounds, adjectival inflection depends on (i) the order of the operations Agree and Insertion and on (ii) the interaction of these operations with the Strict Cycle Condition and the Minimal Link Condition.
We study the structure of Nash equilibria in generic n x n games. A game is said to have a sandwich structure in Nash equilibria if there is a mixed strategy Nash equilibrium "inside" every collection of pure strategy Nash equilibria. A sufficient condition, which solely relies on the ordinal information of the game, is given for a generic n x n game to have a sandwich structure in Nash equilibria. We provide a lower bound on the number of Nash equilibria and determine the stability of each equilibrium in games with a sandwich structure in Nash equilibria. Moreover, when the number of pure strategy Nash equilibria is equal to the number of pure strategies available to each player, the exact structure of Nash equilibria can be determined. (C) 2019 Elsevier Inc. All rights reserved.
Audio is a natural way of communication among persons. Nowadays, many cases of Phone-tapping, hacking of E-mail having some audio files have been reported. Hence, for sending a secret message in audio file over the internet, security and confidentiality must be assured. A secret message is commonly transmitted in encrypted form to assure confidentiality/security using a single key. This does not serve the purpose completely as knowing the key, the whole secret can be revealed. To enhance the security of the secret, sending it through multiple units is preferred. Here, a novel approach is proposed for the same. In the proposed approach an audio secret is divided into n audio shares such that information contained in any proper subset of share/shares (unit) is insignificant. With all the shares only secret can be revealed after performing some computation. Authenticity of the revealed secret can also be confirmed (if necessary) by checking the integrity of individual shares received. If any share is lost during transmission, the proposed scheme has the facility to determine the share number of the lost one, so that request may be sent for resending the same. The proposed scheme is suitable for real-time audio communication as the construction of shares is based upon the available bandwidth. Also, it does not need any cover audio to transmit the share. Experimentally, Mean Opinion Score (MOS) and correlation coefficient (r(S, S-r)) between input secret and revealed secret are found 5 and 0.99 respectively when there is no attack during the transmission. In case the total (either in one or more shares) attack is less than 50% of the size of a single share, MOS of the revealed secret lies between 3.8 to 4.