In 1965, the K-27 submarine with an emergency portside reactor with unloaded spent nuclear fuel (SNF) was scuttled in Stepovoy Bay (Novaya Zemlya). The source of radioactivity is nuclear fuel in the port side reactor and fuel carried into the corresponding steam generator. Before scuttling, the power plant elements were sealed with furfural, and the entire compartment was then filled with bitumen. It is believed that when water enters the reactor core, a self-sustaining fission chain reaction (SCR) will occur. However, this process is possible only if the above-mentioned protective barriers are violated. The state of the protective barriers can be judged by the magnitude and variations of the radioactive background on the deck and near the submarine on the seabed. Thus, the most important task of monitoring and preventing an emergency situation on the K-27 is constant monitoring of the environment (ecology) in Stepovoy Bay in general and near the submerged submarine in particular. The article considers the results of research on the submarine and its environment, including an expedition of the R/V Akademik Mstislav Keldysh (cruise 92, 2023), when for the first time the parameters of the radioactive background were measured directly on the submarine’s robust hull near the reactor compartment.

The reaction of the tetrahedral rhenium arsenide cluster K8[Re4As2(AsO)2(CN)12] with molten KF·HF is studied. The reaction affords complex K6[Re4As2(AsO)F(CN)12]·3H2O·KF (I). The substitution of one (µ3-AsO)3– ligand by µ3-F– is shown to occur during the reaction, and the remained internal ligands are not involved in the reaction. The phase purity of the synthesized compound and the absence of impurities of different compositions are confirmed by phase X-ray diffraction (XRD) and mass spectrometry. The structure of complex I is determined by single-crystal XRD (CIF file CCDC no. 2362544).

The (Bu4N)2[Mo6I8(CN)5(OEt)]·2H2O and (Bu4N)2[W6I8(CN)4(OEt)2]·H2O·EtOH cluster complexes are prepared by the reaction of (Bu4N)2[M6I8I6] (M = Mo, W) with NaCN in ethanol and subsequent recrystallization from an aqueous ethanol solution. The structure of both compounds is determined by XRD. The external ligand environment of the anions contains CN– and OEt– ligands. The behavior of the complexes in an aqueous solution is studied by electron spectroscopy.

The diverging relaxation time in approaching hypothetical ideal glass transition is a subject of hot debate. In the current paper we demonstrate, how diverging relaxation time and turning excess entropy to zero can be avoided, using as an example the model molecular glassformer, propylene carbonate. For this purpose we compare its thermodynamic and dielectric relaxation properties, both known from the literature. The agreement between two sets of data can be achieved, if we suppose, that enthalpy of supercooled liquid propylene carbonate is governed by activation law, and relaxation time follows double exponential law. We propose the generalized Adam-Gibbs law to reconcile this two dependencies, and qualitatively discuss its implications.

Реакцией (Bu4N)2[{M6I8}I6] (M = Mo, W) с NaCN в этаноле и последующей перекристаллизацией из водно-этанольного раствора получены кластерные комплексы состава (Bu4N)2[{Mo6I8}(CN)5(OEt)]·2H2O и (Bu4N)2[{W6I8}(CN)4(OEt)2]·H2O·EtOH. Строение обоих соединений установлено методом РСА. Внешнее лигандное окружение анионов содержит лиганды CN– и OEt–. Поведение комплексов в водном растворе исследовано методом электронной спектроскопии.

The results of seismoacoustic studies of the shelf of southeastern Crimea, which were conducted in the years 2018–2023 by researchers of the Shirshov Institute of Oceanology, Russian Academy of Sciences (Moscow, Russia), with seismoacoustic and acoustic profile recorders, are presented. The Cenozoic section of the southeastern shelf of Crimea is described on the basis of engineering–geological drilling data. Anomalous areas compared with gas occurrences are revealed during the interpretation of continuous seismoacoustic profiling data in the bottom part of the section.

The results of seismoacoustic studies carried out in the years 2020–2023 on the shelf of southeastern Crimea by employees of the Shirshov Institute of Oceanology, Russian Academy of Sciences, using an original complex of technical means, including seismoacoustic and acoustic profilers are discussed. The data obtained made it possible to clarify the position of the paleo valleys and to provide a seismostratigraphic reference of the reflecting horizons with the identification of the main seismic complexes in the Pleistocene–Holocene part of the section. Seismic facies analysis of the wave field made it possible to clarify the paleogeographic conditions for the formation of paleo valleys.

The diverging relaxation time in approaching hypothetical ideal glass transition is a subject of hot debate. In the current paper we demonstrate, how diverging relaxation time and turning excess entropy to zero (which is an essence of Kauzmann's paradox) can be avoided, using as an example the model molecular glassformer, propylene carbonate. For this purpose we compare its thermodynamic and dielectric relaxation properties, both known from the literature. The agreement between two sets of data can be achieved, if we suppose, that enthalpy of supercooled liquid propylene carbonate is governed by activation law, and relaxation time follows double exponential law. We propose the generalized Adam-Gibbs law to reconcile this two dependencies, and qualitatively discuss its implications.

Electrode polarization effects are an important issue in electrochemistry. Here we report investigation of electrode polarization effects in ethanol (used as a model material), in solid and liquid phases at high pressures. Application of pressure has dramatic effect on electrode polarization. Firstly, it significantly reduces the fractional power exponent, which dominates the low-frequency electrode polarization impedance, from approximately 1 at ambient pressure to less than 0.1 at 1.3 GPa. At pressure we can observe transition of electrode polarization impedance from fractional frequency law to inversely proportional to frequency relationship. This transition observed for the first time solves the problem with analytical limitation of electrode polarization effects at higher frequencies. Experimental data fitting by the procedure proposed by us, enables extracting the temperature dependencies of dielectric constant and dielectric relaxation frequency in the solid phase of ethanol at high pressures.

В статье рассмотрены результаты изучения современного рельефа дна и сейсмоакустического зондирования шельфа, позволившие восстановить фрагменты положения древней гидрологической сети и определить связи береговых и субаквальных морфоструктур.В целом исследование выполнялось в течение трех лет в рамках проекта РФФИ № 20-05 00384_А, целью которого являлось познание современных механизмов формирования Крымского шельфа.Рассматриваемый фрагмент исследований в 2022 г. включал морские экспедиционные натурные работы на внешнем шельфе Южного Крыма с борта НИС «Профессор Водяницкий» (124 рейс) с использованием сейсмоакустической аппаратуры профилирования донных отложений, а также эхолотирования и гидролокации бокового обзора.Опыт предыдущих исследований показал высокую эффективность применения аппаратуры акустического профилирования АП-5Т, разработки Лаборатории гидролокации дна ИО РАН, включающей буксируемый носитель акустических антенн, электронный блок и программное обеспечение.В результате были получены данные позволившие сформировать новые представления о строении континентальной окраины Крыма в виде региональных и сводной геоморфологических карт шельфа Крыма, а также профилей строения осадочной толщи.Выполненные исследования Южного шельфа Крыма позволяют существенно дополнить

In TbFeO 3 orthoferrite at temperatures below the antiferromagnetic ordering temperature for the terbium subsystem (∼3.2 K), the electric polarization P a ( H b ) induced by a magnetic field H b along the a axis is found. Such polarization is accompanied by anomalies related to metamagnetic (for Tb) and spin-reorientation (for Fe) transitions. At low magnetic fields | H | < H cr1 ∼ 5 kOe, the P a ( H b ) dependence exhibits a strong hysteresis and has a “butterfly” shape, while in intermediate-field magnetic configurations, | H cr1 | < | H | < | H cr2 | ~ 18 kOe, the sign of the polarization is determined by the sign of an applied electric field, and the P a ( H b ) dependence turns out to be nonmonotonic. A qualitative explanation of the observed effects is given in the framework of a symmetry analysis of the allowed magnetoelectric interactions in the field-induced magnetic structures.

В статье приведены результаты натурных исследований и наблюдений окружающей водной среды Карского моря в связи с захороненными в заливах восточного побережья Новой Земли и в Новоземельской впадине радиоактивными отходами (РАО) эксплуатации атомного подводного и ледокольного флота, а также затопленными ядерно и радиационно опасными объектами (ЯРОО).Объекты затоплены в Карском море в районах с различными географическими и гидрометеорологическими характеристиками на разных глубинах.В этой связи интерес представляет процесс воздействия плавающего и сплоченного льда на объекты, затопленные в разных районах моря, учитывая, что воздействие льда (торосы, айсберги) на морское дно арктических морей зарегистрировано по наличию следов ледовой экзарации до глубин 120 м.Крупными (десятки метров) объектами РАО и ЯРОО являются реакторные отсеки аварийных АПЛ и судов с твердыми радиоактивными отходами (ТРО), а также отработавшим и неотработавшим ядерным топливом (ОЯТ).Повреждение РАО и ЯРОО ледовым покровом может привести к разрушению защитных барьеров, отделяющих ядерное топливо и РАО от окружающей среды, с последующим ее

The article presents results of field studies of the environmental assessment of the bays of the eastern coast of Novaya Zemlya in connection with potentially dangerous objects flooded in this region, which are the nuclear fleet operation waste products. In the course of these studies, technology was used based on remote-controlled and towed uninhabited underwater vehicles (ROV and UTSI), as well as side-view sonar (SSS) developed at IO RAS. To detail information about the condition of emergency facilities and operational waste flooded in 60 years at Tsivolki bay, a deep-water UTSI “Video Module” was used. It is equipped with video and photo cameras, a high-frequency SSS, a depth gauge, an altimeter, a laser scale pointer, as well as auxiliary equipment that ensures the functioning of research systems. Observations in the Gulf of Tsivolki using instrumental technologies made it possible to identify underwater objects whose existence was known only from archival data. Monitoring of the condition of objects was provided using RAM-family gamma-ray spectrometers developed at the Kurchatov Institute Research Center. The nature of the recorded gamma-ray spectra generally corresponds to the measurement results obtained during the assembly survey in 2010 and 2015, and indicates the integrity of the internal protective barriers.

We consider nonstationary diffusion in a medium with random traps-sinks. We study the self-averaging of the mean-square displacement (MSD) of the ensemble of N particles in the fluctuational long-time limit. We demonstrate that MSD of survivors is self-averaging with respect to the number of engaged particles N and is strongly non-self-averaging with respect to time t. To measure MSD of survivors with required accuracy at the required time of observation t0, the initial number of particles N0 must be exponentially large in t0. Any N0, whatever large, will be insufficient at long enough time. In the formulation, when all particles, both survivors and trapped ones, contribute to MSD, we find self-averaging in N and non-strong non-self-averaging over t.

The article reports information on the organization, performance, and main results obtained on expeditionary cruise 85 of the R/V Akademik Mstislav Keldysh to the Kara Sea on August 27–September 30, 2021. The main objective was to study the state of underwater radioactive waste disposals and ecology in the bays of Novaya Zemlya and in the Novaya Zemlya Depression. Sonar and video survey equipment, as well as gamma-ray spectrometers and unmanned underwater vehicles, were used for the research. Benthic and bottom sediment samples were taken for subsequent laboratory analysis. The locations of a number of potentially hazardous objects have been confirmed for the first time. Detailed information about known objects was obtained by multibeam mapping technology.

We consider nonstationary diffusion in a medium with static random traps-sinks. We address the problem of self-averaging of the survival probability (or concentration) of the ensemble of $$N$$ particles in the fluctuation regime in the long-time limit. We demonstrate that the relative standard deviation of the survival probability decreases with the number of engaged particles as $$N^{ - 1/2}$$ and increases with time as a stretched exponential $$\approx \exp \left[ {const_{d,\,1} t^{{d/\left( {d + 2} \right)}} } \right]$$ . Therefore, the survival probability is self-averaging in parameter $$N$$ and is strongly non-self-averaging over time $$t$$ . To measure the concentration with the required accuracy at the required time of observation $$t_{0}$$ , the initial number of particles $$N_{0}$$ must be exponentially large in $$t_{0}$$ . At later times $$t > t_{0}$$ the relative fluctuations continue to diverge exponentially beyond the required accuracy. In the limit of high dimensions, there is no tendency to restore self-averaging over time in the ensemble of $$N$$ particles. The solution in 1D is exact. In higher dimensions, the leading exponential term of the solution is exact.

Федеральное государственное бюджетное учреждение наукиИнститут неорганической химии им.А. В. Николаева Сибирского отделения Российской академии наук

We consider the nonstationary diffusion of particles in a medium with static random traps-sinks. We address the problem of self-averaging of the particle concentration (or survival probability) in the fluctuation regime in the long-time limit. We demonstrate that the concentration of surviving particles and their trapping rate are strongly non-self-averaging quantities. Their reciprocal standard deviations grow with time as the stretched exponentials ≈expconstd,1td/d+2. In higher dimensions d, no tendency to restore self-averaging is revealed. Exponential non-self-averaging is preserved for d=∞. The 1D solution and the leading exponential terms in higher dimensions are exact. The strong non-self-averaging of the concentration signifies the poor reproducibility of single measurements in different samples, both in experiments and simulations.