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Quantitative evaluation of LAL productivity of colloidal nanomaterials:Which laser pulse width is more productive,ergonomic,and economic?

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Chinese Physics B 2022年第7期31卷 23-33页

作者： Alena Nastulyavichus nikita Smirnov Sergey Kudryashov P.N.Lebedev Physical Institute of the Russian Academy of Sciences MoscowRussia

Near-IR(wavelength≈1μm)laser ablation of bulk,chemically-inert gold in water was compared for different laser pulse width in broad the range of 300 fs–100 ns,comparing a number of key ablation characteristics:mass loss,singleshot crater volume and extinction coefficient of the generated colloidal solutions taken in the spectral ranges of interband transitions and localized plasmon *** to related air-based ablation results,at the given fluences laser ablation in the liquid resulted in the maximum ablation yield per unit energy and maximum NP yield per pulse and per unit energy for the picosecond lasers,occurring at subcritical peak pulse powers for laser *** self-focusing effect was demonstrated to yield in incomplete,effectively weaker focusing in the water filaments of ultrashort laser pulses with supercritical peak powers,comparing to linear(geometrical)focusing at sub-critical peak *** the other,nanosecondpulse extreme the high ablation yield per pulse,but low ablation yield per unit energy and low NP yield per pulse and per unit energy were related to strong ablation plasma screening,providing mass removal according to the well-established scaling relationships for *** comparison of the ablation and nanoparticle generation efficiency versus the broad fs–ns laser pulse width range was enabled in terms of productivity,economicity,and ergonomicity,using the proposed universal quantitative criteria.

关键词： laser ablation of gold in liquid ablated mass critical power for self-focusing filamentation

A novel freemium code SAND(v1.0)for generation of randomly packed beds

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Particuology 2024年第12期95卷 198-211页

作者： nikita Shadymov Viacheslav Papkov Dmitry Pashchenko Samara State Technical University Molodogvardeiskaya 244 StSamara443100Russia Department of Mechanical Engineering(Robotics) Guangdong Technion-Israel Institute of Technology241 Daxue RoadShantouGuangdong515063China Faculty of Mechanical Engineering Technion-Israel Institute of TechnologyTechnion CityHaifa3200003Israel Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion Guangdong Technion—Israel Institute of TechnologyGuangdong515063China

The main current approaches for generation of the packed bed models are based on rigid body dynamics(RBD)and Newton's laws(discrete element methods-DEM).This paper deals with the development and analysis of a novel code based on analytical geometry approach for the packed bed *** architecture and main algorithms of the novel code are described and *** parameters of the packed bed generated via the novel code are compared with experimental data and packed beds generated via Blender(RBD),Yade(DEM).The novel code demonstrates many advantages,such as good correlation with experimental data,no overlaps between pellets in the packed bed,and a low computational time for packed bed *** packed bed model can be directly exported *** *** advantages are also demonstrated and *** novel code is attached to this paper and can be freely used by engineers and scientists.

关键词： Packed bed Discrete element method Python-based code CAD software

Diversity considerations in wideband radar detection of migrating targets in clutter

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Science China(Information Sciences) 2019年第4期62卷 31-40页

作者： Franois LE CHEVALIER nikita PETROV Department Microwave Sensing Signals and Systems (MS3) Delft University of Technology

Wideband radars have been proposed for detection of moving targets, with unique capability of non-ambiguous detection due to range migration. Moreover, frequency diversity has long been used for mitigating the fading effects caused by target and clutter fluctuations. The real benefits of wideband radars are difficult to analyze, since they derive from the combined effects of target resolution in range, migration over successive cells of clutter, Doppler resolution and instantaneous bandwidth, and residual ambiguities in Doppler. In order to contribute to a better understanding of the benefits of agile transmissions for detection of moving targets, clutter cancelling performances of wideband radars are examined, demonstrating clear benefits from diversity on clutter and target, primarily – but not only – obtained through target migration effects. Special attention is given to long-range surveillance and tracking, and new results on detection of moving targets in clutter will be provided to demonstrate the effectiveness of these new architectures for small targets detection at long range, in difficult environments. Finally, recommendations for system designs that improve the discrimination of moving targets against fixed and diffuse clutter are presented.

关键词： radar extended target frequency diversity wideband detection target migration clutter cancelling

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地中海的宁静 EKONIKA莫斯科旗舰店

室内设计与装修 2025年第1期 58-63页

作者：无 Anna Lvovskaia Boris Lvovskiy Fedor Goreglyad Maria Romanova Vasilii Portnyagin nikita Subbotin(摄影) 秋落(编译) DA bureau 不详 Landon Studio

EKONIKA是俄罗斯最大的鞋类连锁店之一,已上市30多年。在过去的5年里,该品牌发生了重大变化,变得更加现代化,面向更年轻的受众。这些变化需要改变连锁店的视觉形象,这也是设计师工作的难点。作为EKONIKA鞋类和配饰连锁店品牌重塑的一部... 详细信息

EKONIKA是俄罗斯最大的鞋类连锁店之一,已上市30多年。在过去的5年里,该品牌发生了重大变化,变得更加现代化,面向更年轻的受众。这些变化需要改变连锁店的视觉形象,这也是设计师工作的难点。作为EKONIKA鞋类和配饰连锁店品牌重塑的一部分,设计师为该品牌的展厅开发了全新的视觉解决方案。

关键词：品牌重塑连锁店视觉形象地中海鞋类旗舰店俄罗斯 EK

Hyperbolicity of unitary involutions

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Science China Mathematics 2012年第5期55卷 937-945页

作者： KARPENKO nikita A. Institut de Math'ematiques de Jussieu Universit'e Pierre et Marie CurieParisFrance

We prove the so-called Unitary Hyperbolicity Theorem,a result on hyperbolicity of unitary *** analogous previously known results for the orthogonal and symplectic involutions are formal consequences of the unitary *** the original proofs in the orthogonal and symplectic cases were based on the incompressibility of generalized Severi-Brauer varieties,the proof in the unitary case is based on the incompressibility of their Weil transfers.

关键词： algebraic groups involutions projective homogeneous varieties Chow groups and motives Steenrod operations

Model Failure and Context Switching Using Logic-Based Stochastic Models

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Journal of Computer Science & Technology 2010年第4期25卷 665-680页

作者： nikita A.Sakhanenko George F.Luger Institute for Systems Biology Computer Science University of New Mexico

This paper addresses parameter drift in stochastic models. We define a notion of context that represents invariant, stable-over-time behavior and we then propose an algorithm for detecting context changes in processing a stream of data. A context change is seen as model failure, when a probabilistic model representing current behavior is no longer able to ＂fit＂ newly encountered data. We specify our stochastic models using a first-order logic-based probabilistic modeling language called Generalized Loopy Logic （GLL）. An important component of GLL is its learning mechanism that can identify context drift. We demonstrate how our algorithm can be incorporated into a failure-driven context-switching probabilistic modeling framework and offer several examples of its application.

关键词： context failure-driven online learning probabilistic reasoning

Oxidative chemical pretreatment by piranha solution for enhanced methane yield of wheat straw:mechanism and kinetic study

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Waste Disposal and Sustainable Energy 2023年第3期5卷 351-366页

作者： nikita Kanaujia Shalu Rawat Jiwan Singh Department of Environmental Science Babasaheb Bhimrao Ambedkar UniversityLucknow226025India

The present research work aims to explore the potency of piranha solutions at the best-optimized concentrations,i.e.,40%and 30%to reduce the recalcitrant and heterogeneous structure of wheat straw,and the treated wheat straw was denoted as WS40 and *** effect of pretreatment on wheat straw was determined by anaerobic digestion(AD)in a batch mode,followed by the analysis of soluble chemical oxygen demand(sCOD)and volatile fatty acids(VFAs).After pretreatment,the surface fibers shattered and detached,showing a distorted surface of wheat *** increase in the crystallinity of wheat straw after pretreatment was also observed due to the removal of amorphous cellulose and *** in methane yield was obtained on the 9th day,which was 103±6.92 and 99.33±0.57 mL/d for WS40 and WS30,*** water measurement revealed that the pretreatment of wheat straw minimized the hydrolysis period by 14 *** also improved the methane yield by 2.65(WS40)and 2.45(WS30)fold in comparison with the control which yielded 35.66 mL/d methane on the 23rd *** modified Gompertz model(MGM),logistic function model(LFM)and transference function model(TFM)adequately described the degradation process and explained the kinetic behavior of the cumulative methane *** the three models,MGM was found to fit best for the methane yield of WS40 and WS30.

关键词： Anaerobic digestion Wheat straw Oxidative pretreatment Piranha solution Methane

Mathematical modeling of icing process of the outer surface of the hull for a marine vessel

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Journal of Hydrodynamics 2023年第2期35卷 232-239页

作者： Konstantin Koshelev Andrey Osipov Sergei Strijhak nikita Tryaskin ISP RAS MoscowRussia Saint-Petersburg State Marine Technical University Saint-PetersburgRussia

The task of studying the process of icing is important due to the operation of large ships and fishing vessels in the seas of the Arctic *** this paper the ice accretion simulation for fishing vessel has been done at different Reynolds and Froude numbers.A hybrid approach was used for modeling:first,the approach based on Reynolds-averaged Navier-Stokes(RANS)model and volume of fluid(VOF)method with interDyMFoam solver was used for ship modelling in waves,second,RANS model and Euler-Lagrangian approach with iceFoam solver for ice accretion process modelling for ship with hull was *** k-ωSST turbulence model with wall functions was used for the RANS *** the help of the interDyMFoam solver,the position of water jet and liquid droplets in space were determined during the movement of the ship and taking into account the waves in the *** the help of iceFoam solver,the process of ice accretion on the surface of the vessel was *** calculations were run for different number Reynolds,*** analysis of mesh convergency was *** distribution of ice thickness and water film on the ship’s surface is *** simulations were performed on a high-performance cluster in parallel mode.

关键词： Ship sea safety climate movement modelling turbulence model water spray droplets velocity ice film mass

Whispering-gallery microlasers for cell tagging and barcoding:the prospects for in vivo biosensing

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Light(Science & Applications) 2021年第5期10卷 710-712页

作者： nikita Toropovo Frank Vollmer Department of Physics and Astronomy Living Systems InstituteUniversity of ExeterExeter EX44QDUK

Researchers in the field of whispering-gallery-mode(WGM)microresonators have proposed biointegrated low-threshold WGM lasers,to enable large-scale parallel single-cell tracking and *** the reported devices have so far been primarily investigated in model applications,most recent results represent important steps towards the development of in vivo tags and sensors that utilize the unique and narrow spectral features of miniature WGM lasers.

关键词： lasers vivo utilize