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Efficient cold atom source from a single-layer atom chip

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Chinese Optics Letters 2024年第6期22卷 103-108页

作者： Petr Skakunenko Darya Bykova Anton Afanasiev Alexey Kalmykov Roman Kirtaev Victor Balykin institute of Spectroscopy Russian Academy of Sciences Moscow 108840Russia moscow institute of Physics and Technology Moscow 141700Russia Skolkovo institute of Science and Technology Moscow 121205Russia National research University Higher School of Economics Moscow 101000Russia Present affiliation:Emerging Technologies research Center XPANCEODubaiUnited Arab Emirates

We developed a new single-layer atom chip with an additional U-shaped current-carrying *** new U-shaped microwire creates optimized magnetic field distribution,which increases the trapping volume of a magneto-optical trap(MOT) near the *** approach allows one to localize more atoms,while a setup remains relatively simple (single-layer approach) and consumes low current (up to 10 A). The total number of trapped^(87)Rb atoms in our setup is 5×10^(7).

关键词： atom chip cold atoms laser cooling magneto-optical trap U-MOT

Unveiling the early universe:Axion-like particles and their role in primordial structure formation

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 178-179页

作者： Sergey G.Rubin National research Nuclear University MEPhI(moscow Engineering Physics institute) Moscow 115409Russia

The groundbreaking discovery of gravitational waves(GWs)by the LIGO-VIRGO-KAGRO collaboration has revolutionized our understanding of the universe and opened up a new way of observing cosmic events. Unlike light waves... 详细信息

关键词： universe gravitational cosmic

Measurement of yields and angular distributions ofγ-quanta from the interaction of 14.1 MeV neutrons with oxygen,phosphorus,and sulfur

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Chinese Physics C 2024年第3期48卷 79-92页

作者： D.N.Grozdanov N.A.Fedorov S.B.Dabylova Yu.N.Kopatch I.N.Ruskov V.R.Skoy T.Yu.Tretyakova C.Hramco P.I.Kharlamov G.V.Pampushik P.G.Filonchik A.V.Andreev Joint institute for Nuclear research(JINR) DubnaRussia institute for Nuclear research and Nuclear Energy Bulgarian Academy of SciencesSofiaBulgaria Faculty of Physics Lomonosov Moscow State UniversityMoscowRussia L.N.Gumilyov Eurasian National University AstanaKazakhstan Skobeltsyn institute of Nuclear Physics Moscow State UniversityMoscowRussia institute of Chemistry of Moldova ChisinauRepublic of Moldova moscow institute of Physics and Technology MoscowRussia

A study of the inelastic scattering of neutrons with an energy of 14.1 MeV on the nuclei of oxygen,phosphorus,and sulfur was performed at the TANGRA facility at JINR(Dubna).The experiment aimed to refine existing data and obtain new data on the yields and angular distributions ofγ-quanta emitted by the studied nuclei due to neutron-induced nuclear reactions using the tagged neutron *** types of detector systems were used to registerγ-***γ-ray yields were measured using a high-purity germanium(HPGe)*** angular distributions ofγ-rays were obtained using a system of 18 scintillation detectors based on bismuth germanite Bi_(4)Ge_(3)O_(12)(BGO)located around the *** performed experiments measured the yields of two transitions for the reaction of tagged neutrons with 16O,nine transitions for the reaction with ^(31)P,and nine transitions for the reaction with ^(32)S for the first *** angular anisotropy of theγ-radiation accompanying the inelastic scattering of neutrons with an energy of 14.1 MeV on ^(31)P nuclei was also measured for the first time.

关键词： tagged neutron method yields of gamma-quanta high-resolution gamma-spectrometry neutron-nuclear reactions neutron scattering

Atherosclerosis originating from childhood:Specific features

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Journal of Biomedical research 2024年第3期38卷 233-240页

作者： Anastasia V.Poznyak Alexey A.Yakovlev MikhailА.Popov Elena B.Zhigmitova Vasily N.Sukhorukov Alexander N.Orekhov institute for Atherosclerosis research Moscow 121609Russia Federal research and Clinical Center of Intensive Care Medicine and Rehabilitology Moscow 109240Russia Department of Cardiac Surgery Moscow Regional Research and Clinical InstituteMoscow 129110Russia Laboratory of Angiopathology Institute of General Pathology and PathophysiologyMoscow 125315Russia

Atherosclerosis is extremely ***,it is considered a disease of older people,who most often experience problems with the heart and blood *** much attention from the scientific community has been paid to studying the association between aging and atherosclerosis,as well as its consequences,there is evidence that atherosclerosis occurs at an early *** may form both during intrauterine development and in *** plays an important role in childhood atherosclerosis,along with previous infectious diseases and excess weight of both the child and the *** the present review,we examined the development of atherosclerosis and the prerequisites in childhood.

关键词： atherosclerosis childhood pediatrics cardiovascular disease

Ion heat transport in electron cyclotron resonance heated L-mode plasma on the T-10 tokamak

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Plasma Science and Technology 2024年第4期26卷 52-60页

作者： V.A.KRUPIN M.R.NURGALIEV A.R.NEMETS I.A.ZEMTSOV S.D.SUNTSOV T.B.MYALTON D.S.SERGEEV N.A.SOLOVEV D.V.SARYCHEV D.V.RYJAKOV S.N.TUGARINOV N.N.NAUMENKO National research Centre“Kurchatov institute” Moscow 123182Russia Bauman moscow State Technical University Moscow 105005Russia Institution“Project Center ITER” Moscow 123098Russia JSC“SOLAR” Minsk 220034Belarus

Anomalous ion heat transport is analyzed in the T-10 tokamak plasma heated with electron cyclotron resonance heating(ECRH) in second-harmonic extra-ordinary mode. Predictive modeling with empirical scaling for Ohmical heat conductivity shows that in ECRH plasmas the calculated ion temperature could be overestimated, so an increase of anomalous ion heat transport is required. To study this effect two scans are presented: over the EC resonance position and over the ECRH power. The EC resonance position varies from the high-field side to the low-field side by variation of the toroidal magnetic field. The scan over the heating power is presented with on-axis and mixed ECRH regimes. Discharges with high anomalous ion heat transport are obtained in all considered regimes. In these discharges the power balance ion heat conductivity exceeds the neoclassical level by up to 10 times. The high ion heat transport regimes are distinguished by three parameters: the ratio Te/Ti, the normalized electron density gradient R/■, and the ion–ion collisionality νii~*. The combination of high Te/Ti, high νii~*, and R/■=6-10 results in values of normalized anomalous ion heat fluxes up to 10 times higher than in the low transport scenario.

关键词： tokamak L-mode electron cyclotron resonance heating ion heat transport

Ensemble successor representations for task generalization in offline-to-online reinforcement learning

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Science China(Information Sciences) 2024年第7期67卷 240-255页

作者： Changhong WANG Xudong YU Chenjia BAI Qiaosheng ZHANG Zhen WANG space Control and Inertial Technology research Center Harbin Institute of Technology Shanghai Artificial Intelligence Laboratory Shenzhen research institute of Northwestern Polytechnical University School of Cybersecurity Northwestern Polytechnical University

In reinforcement learning(RL), training a policy from scratch with online experiences can be inefficient because of the difficulties in exploration. Recently, offline RL provides a promising solution by giving an initialized offline policy, which can be refined through online interactions. However, existing approaches primarily perform offline and online learning in the same task, without considering the task generalization problem in offline-to-online adaptation. In real-world applications, it is common that we only have an offline dataset from a specific task while aiming for fast online-adaptation for several tasks. To address this problem, our work builds upon the investigation of successor representations for task generalization in online RL and extends the framework to incorporate offline-to-online learning. We demonstrate that the conventional paradigm using successor features cannot effectively utilize offline data and improve the performance for the new task by online fine-tuning. To mitigate this, we introduce a novel methodology that leverages offline data to acquire an ensemble of successor representations and subsequently constructs ensemble Q functions. This approach enables robust representation learning from datasets with different coverage and facilitates fast adaption of Q functions towards new tasks during the online fine-tuning *** empirical evaluations provide compelling evidence showcasing the superior performance of our method in generalizing to diverse or even unseen tasks.

关键词： offline reinforcement learning online fine-tuning task generalization successor representations ensembles

Orthogonal waveform design with fractional programming on the ambiguity suppression of SAR systems

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Science China(Information Sciences) 2024年第9期67卷 263-279页

作者： Yunkai DENG Yongwei ZHANG Zhimin ZHANG Wei WANG Heng ZHANG Department of space Microwave Remote Sensing System Aerospace Information Research InstituteChinese Academy of Sciences

Waveform diversity(WD) represents a dynamic and transformative technology widely used in radar systems to enhance sensitivity and discrimination capabilities. Recently, WD techniques have been extensively explored for their potential ambiguity suppression within synthetic aperture radar(SAR) *** these, the alternate transmitting mode combined with orthogonal waveforms emerges as a particularly promising solution. This study focuses on optimizing the power spectrum density(PSD) of signals to design and generate an orthogonal waveform pair that achieves both a low cross-correlation-to-autocorrelation ratio(CAR) and satisfactory imaging performance. Initially, we construct a fractional programming model with convex constraints to minimize the CAR. To address this challenge, we introduce an iterative optimization procedure for the PSD variable, which sequentially reduces the CAR. Each optimization step can be efficiently solved using a quadratically constrained quadratic program, ensuring that the resulting computational complexity remains low. Building on the optimized PSD, we established a parametric piecewise linear model to generate an orthogonal waveform pair. This model not only maintains a low CAR but achieves satisfactory imaging performance in real-time applications. Consequently, this orthogonal waveform pair effectively suppresses range ambiguity in SAR systems. Finally, we demonstrated the practicability and effectiveness of the proposed orthogonal waveforms through detailed simulation experiments, specifically targeting ambiguity suppression in conventional quad-polarization SAR systems.

关键词： synthetic aperture radar (SAR) waveform diversity (WD) ambiguity suppression orthogonal waveform fractional programming power spectrum density (PSD)

Simple collective model for nuclear chiral mode

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Frontiers of physics 2024年第2期19卷 1-5页

作者： R.V.Jolos E.A.Kolganova D.R.Khamitova Joint institute for Nuclear research 141980 DubnaMoscow regionRussia Dubna State University 141982 DubnaMoscow RegionRussia

A simple semi-analytical collective model that takes into account the limitations of the variation interval of the collective variable is suggested to describe the chiral dynamics in triaxial odd−odd nuclei with a fixed particle−hole *** collective Hamiltonian is constructed with the potential energy obtained using the postulated ansatz for the wave function symmetric with respect to chiral *** diagonalizing the collective Hamiltonian the wave functions of the lowest states are obtained and the evolution of the energy splitting of the chiral doublets in transition from chiral vibration to chiral rotation regime is demonstrated.

关键词： collective model nuclear chiral

Identification of Proteins and Genes Associated with Hedgehog Signaling Pathway Involved in Neoplasm Formation Using Text-Mining Approach

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Big Data Mining and Analytics 2024年第1期7卷 107-130页

作者： Nadezhda Yu.Biziukova Sergey M.Ivanov Oga A.Tarasova Department of Bioinformatics Institute of Biomedical ChemistryMoscow 119121Russia Department of Bioinformatics Pirogov Russian National Research Medical UniversityMoscow 117997Russia

Analysis of molecular mechanisms that lead to the development of various types of tumors is essential for biology and medicine,because it may help to find new therapeutic opportunities for cancer treatment and cure including personalized treatment *** of the pathways known to be important for the development of neoplastic diseases and pathological processes is the Hedgehog signaling pathway that normally controls human embryonic *** accumulation of various types of biological data,including interactions between proteins,regulation of genes transcription,proteomics,and metabolomics experiments results,allows the application of computational analysis of these big data for identification of key molecular mechanisms of certain diseases and pathologies and promising therapeutic *** aim of this study is to develop a computational approach for revealing associations between human proteins and genes interacting with the Hedgehog pathway components,as well as for identifying their roles in the development of various types of *** automatically collect sets of abstract texts from the NCBI PubMed bibliographic *** recognition of the Hedgehog pathway proteins and genes and neoplastic diseases we use a dictionary-based named entity recognition approach,while for all other proteins and genes machine learning method is *** association extraction,we develop a set of semantic *** complete the results of the text analysis with the gene set enrichment *** identified key pathways that may influence the Hedgehog pathway and their roles in tumor development are then verified using the information in the literature.

关键词： text-mining data mining Hedgehog pathway neoplastic processes enrichment analysis pathology molecularmechanisms