The Colley-Tyndall Debate: A Synopsis of the Arguments of Both Speakers

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Security bound for CTR-ACPKM internally re-keyed encryption mode

In 2018 the CTR-ACPKM internally re-keyed block cipher mode was adopted in Russian Standardization System and must pass through the last formal standardization stages in IETF. The main distinctive feature of this mode is that during each message processing, the key, used for data blocks transformation, is periodically changed. In the current paper we obtained the security bound for this mode in the standard IND-CPNA security model

Structure and phase transition in BaThO3: A combined neutron and synchrotron X-ray diffraction study

The structure of BaThO3, obtained by solid state synthesis, was refined for the first time by the Rietveld method using a combination of synchrotron X-ray and neutron powder diffraction data. BaThO3 has an orthorhombic structure at room temperature, in space group Pbnm with a = 6.3491(5), b = 6.3796(4) and c = 8.9907(7) Å. Heating BaThO3 to above 700 °C results in a continuous transition to a second orthorhombic structure, in space group Ibmm, demonstrated by both in situ neutron and synchrotron X-ray powder diffraction measurements. The coefficient of volumetric thermal expansion for BaThO3 is determined to be 1.04 x 10-5 oC-1 from 50 to 625 oC (Pbnm phase), and 9.43 x 10-6 oC-1 from 800 to 1000 oC (Ibmm phase). BaThO3 was found to decompose upon exposure to atmospheric moisture resulting in the formation of ThO2. The thermal expansion of ThO2, which invariably co-exists with BaThO3, is also described.Australian Synchrotron Australian Research Council2019-12-1

Structure and phase transition in BaThO3: A combined neutron and synchrotron X-ray diffraction study

The structure of BaThO3, obtained by solid state synthesis, was refined for the first time by the Rietveld method using a combination of synchrotron X-ray and neutron powder diffraction data. BaThO3 has an orthorhombic structure at room temperature, in space group Pbnm with a = 6.3491(5), b = 6.3796(4) and c = 8.9907(7) Å. Heating BaThO3 to above 700 °C results in a continuous transition to a second orthorhombic structure, in space group Ibmm, demonstrated by both in situ neutron and synchrotron X-ray powder diffraction measurements. The coefficient of volumetric thermal expansion for BaThO3 is determined to be 1.04 x 10-5 oC-1 from 50 to 625 oC (Pbnm phase), and 9.43 x 10-6 oC-1 from 800 to 1000 oC (Ibmm phase). BaThO3 was found to decompose upon exposure to atmospheric moisture resulting in the formation of ThO2. The thermal expansion of ThO2, which invariably co-exists with BaThO3, is also described.Australian Synchrotron Australian Research Counci

On the properties of the CTR encryption mode of the Magma and Kuznyechik block ciphers with re-keying method based on CryptoPro Key Meshing

This paper presents a security bound in the standard security model for the Magma cipher CTR encryption mode and the «CryptoPro Key Meshing» (CPKM) re-keying method that was previously used with the GOST 28147-89 cipher. We enumerate the main requirements that should be followed during the development of re-keying methods, then we propose a modified method and justify its advantages over CPKM. We also obtain certain results about the operational features of the Kuznyechik cipher CTR encryption mode with several re-keying methods

Crystal growth of novel 3D skeleton uranyl germanium complexes : influence of synthetic conditions on crystal structures

Five centrosymmetric uranyl germanate compounds, K8BrF(UO2)3(Ge2O7)2, Rb6(UO2)3(Ge2O7)2·0.5H2O, Cs6(UO2)2Ge8O21 and A+2(UO2)3(GeO4)2 (A+ = Rb+, Cs+), were synthesized in this work. K8BrF(UO2)3(Ge2O7)2 and Rb6(UO2)3(Ge2O7)2·0.5H2O were obtained under mixed KF–KBr flux and hydrothermal conditions, respectively. Both structures crystallized in the triclinic P[1 with combining macron] space group and have similar anionic frameworks featuring novel hexagon shaped 12-membered channels. The condensation of two different types of SBU [UGe4] pentamers (A) and (A2) results in the formation of K8BrF(UO2)3(Ge2O7)2 and Rb6(UO2)3(Ge2O7)2·0.5H2O frameworks. Cs6(UO2)2Ge8O21 was obtained from a CsF–CsCl high temperature flux, and it also crystallized in the centrosymmetric triclinic P[1 with combining macron] space group. The structure of Cs6(UO2)2Ge8O21 has a novel oxo-germanate layer composed of germanate tetrahedra and trigonal bipyramids. Two new SBU types, (42·52-A2) and (54-A2) [UGe4] pentamers, were found in the structure of Cs6(UO2)2Ge8O21. A+2(UO2)3(GeO4)2 (A+ = Rb+, Cs+) were synthesized by a high temperature/high pressure (HT/HP) technique, and both structures with oval-shaped 12-membered channels crystallized in the centrosymmetric orthorhombic Pnma space group. The extreme conditions led to the formation of [U2Ge2] tetramers (E), which consist of 7-coordinated U and 5-coordinated Ge. Different synthetic methods of uranyl germanate compounds resulted in a distinct coordination environment of the uranyl cations and a variety of U[double bond, length as m-dash]O and U−O bond lengths, further affecting the dimensionality and types of uranyl units and SBUs. The Raman and IR spectra of the five new phases were collected and analyzed

Effects of Te(IV) Oxo-Anion Incorporation into Thorium Molybdates and Tungstates

The exploration of phase formation in the Th−Mo/W−Te systems has resulted in four mixed oxo-anion compounds from high-temperature solid-state reactions:ThWTe2O9, Th(WO4)(TeO3), ThMoTe2O9, and Th2(MoO4)-(TeO3)3. All four compounds contain edge-sharing thorium polyhedra linked by MoO4/WO6 and different tellurium oxogroups to form three-dimensional frameworks. In ThWTe2O9, each helical Th based chain is connected by four tungstotellurite clusters resulting in a building fragment which has a crosssection of four-leafed clovers. The structure of Th(WO4)(TeO3) exhibits a multilayer-sandwich framework composed of thorium tellurite layers with tungsten chains in between. In the case of the molybdate family, ThMoTe2O9 and Th2(MoO4)(TeO3)3 are built from puckered Th−Te sheets which are further interconnected by MoO4 tetrahedral linkers. The DSC-TG technique was performed to gain insight into the thermal behavior of the synthesized compounds. Raman spectra of as-prepared phases were obtained and analyzed for signature peaks