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Dynamic failure of dry and fully saturated limestone samples based on incubation time concept

Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 125-134页

作者： Yuri v. Petrov ivan v. Smirnov Grigory A. volkov Andrei K. Abramian Anatoliy M. Bragov Stanislav N. verichev Saint Petersburg University Universitetskaya nab. 7-9 Saint Petersburg 199034 Russia Institute of Problems of Mechanical Engineering Russian Academy of Sciences Bolshoj pr. 61 V.O. Saint Petersburg 199178 Russia Lobachevsky State University of Nizhni Novgorod Prospekt Gagarina 23 Nizhny Novgorod 603950 Russia Allseas Engineering B.v. Poortweg 12 Delft 2612 PA The Netherlands

This paper outlines the results of experimental study of the dynamic rock failure based on the comparison of dry and saturated limestone samples obtained during the dynamic compression and split tests. The tests were performed using the Kolsky method and its modifications for dynamic splitting. The mechanical data(e.g. strength, time and energy characteristics) of this material at high strain rates are obtained. It is shown that these characteristics are sensitive to the strain rate. A unified interpretation of these rate effects, based on the structuraletemporal approach, is hereby presented. It is demonstrated that the temporal dependence of the dynamic compressive and split tensile strengths of dry and saturated limestone samples can be predicted by the incubation time criterion. Previously discovered possibilities to optimize(minimize) the energy input for the failure process is discussed in connection with industrial rock failure processes. It is shown that the optimal energy input value associated with critical load, which is required to initialize failure in the rock media, strongly depends on the incubation time and the impact duration. The optimal load shapes, which minimize the momentum for a single failure impact, are demonstrated. Through this investigation, a possible approach to reduce the specific energy required for rock cutting by means of high-frequency vibrations is also discussed.

关键词： Dynamic strength Incubation time criterion Split Hopkinson pressure bar(SHPB) test Tensile strength Compressive strength Water-saturated limestone vibration-assisted rock cutting

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Catalytic performance of ternary Mg-Al-Ce oxides for ethanol conversion into 1-butanol in a flow reactor

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燃料化学学报 2021年第3期49卷 346-357,I0001-I0010页

作者： Olga v.Larina Karina v.valihura Pavlo I.Kyriienko Nina v.vlasenko Dmytro Yu.Balakin ivan Khalakhan Katerina veltruská Tomaz Cendak Sergiy O.Soloviev Svitlana M.Orlyk L.v.Pisarzhevsky Institute of Physical Chemistry of the National Academy of Sciences of Ukraine 31 Prosp.Nauky03028 KyivUkraine Institute of Physics of the National Academy of Sciences of Ukraine 46 Prosp.Nauky03028 KyivUkraine Charles University Faculty of Mathematics and PhysicsDepartment of Surface and Plasma ScienceV Holešovičkách 218000 PragueCzech Republic National Institute of Chemistry Department of Inorganic Chemistry and TechnologyHajdrihova 19SI-1001 LjubljanaSlovenia

An investigation of hydrotalcite-derived ternary Mg-Al-Ce oxides as catalysts for vapour phase condensation of ethanol to 1-butanol in a flow reactor under atmospheric pressure was carried *** Mg-Al-Ce oxide systems with Mg/(Al+Ce)ratio from 1 to 4 were synthesized and characterized by XRD,SEM,NMR,and *** study of acid-base characteristics of the systems with different Mg/(Al+Ce)ratio by NH3/CO_(2)quasi-equilibrium thermal desorption techniques shows that the ratio of the catalyst oxide components(Mg,Al,Ce)can provide acid/base capacity ratio close to 3 for the effectivity of the target *** highest selectivity 68%is reached over Mg-Al-Ce oxide catalyst with the ratio of Mg/(Al+Ce)=2.

关键词： ethanol 1-butanol Mg-Al-Ce hydrotalcite-derived oxides acid-base properties

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Mesoscopic Models of Plants Composed of Metallic Nanowires

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Journal of Bionic Engineering 2013年第3期10卷 368-376页

作者： Galina K. Strukova Gennady v. Strukov Evgeniya Yu. Postnova Alexander Yu. Rusanov ivan S. veshchunov Institute of Solid State Physics Russian Academy of Sciences 142432 Chernogolovka Russia

various metallic structures of complex shape resembling living plant organisms （biomimetics） are produced as a result of self-assembly of nanowires growing on porous membranes in the course of pulse current electrodeposition. These structures occur if the electroplating is continued after the nanowires appear on the membrane surface. By varying the membrane ge- ometry, pulse current electroplating parameters, and alternating electrodeposition from two baths composed of a variety of electrolytes, diverse models were fabricated, including a hollow container with a wall thickness of 10 nm 20 nm. This biomimetic method suggests an analogy between the shape-forming processes of plants and their metallic models. Nanostruc- tured mesostructures of various metals （Ag, Pd, Ni）, alloys （PdNi, Pbln） and hybrid structures .（PdNi/Pb, PdNi/Pbln） were obtained. They can be of interest for fundamental research （self-assembly, morphogenesis） as well as for applications in nanotechnology （catalysis, nanoplasmonics, medicine, superhydrophobic surfaces）.

关键词： templated growth pulse electroplating self-assembly metallic mesostructures nanowires fractal branching biomimetic method

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Nonlinear polaritons in a monolayer semiconductor coupled to optical bound states in the continuum

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Light(Science & Applications) 2020年第1期9卷 1480-1487页

作者： vasily Kravtsov Ekaterina Khestanova Fedor A.Benimetskiy Tatiana ivanova Anton K.Samusev ivan S.Sinev Dmitry Pidgayko Alexey M.Mozharov ivan S.Mukhin Maksim S.Lozhkin Yuri v.Kapitonov Andrey S.Brichkin vladimir D.Kulakovskii ivan A.Shelykh Alexander I.Tartakovskii Paul M.Walker Maurice S.Skolnick Dmitry N.Krizhanovskii ivan v.Iorsh ITMO University Saint Petersburg 197101Russia St.Petersburg Academic University Saint Petersburg 194021Russia Saint Petersburg State University ul.Ulyanovskaya 1Saint Petersburg 198504Russia Institute of Solid State Physics RASChernogolovka 142432Russia Science Institute University of IcelandDunhagi 3IS-107ReykjavikIceland Department of Physics and Astronomy University of SheffieldSheffield S37RHUK

Optical bound states in the continuum(BICs)provide a way to engineer very narrow resonances in photonic *** extended interaction time in these systems is particularly promising for the enhancement of nonlinear optical processes and the development of the next generation of active optical ***,the achievable interaction strength is limited by the purely photonic character of optical ***,we mix the optical BIC in a photonic crystal slab with excitons in the atomically thin semiconductor MoSe_(2) to form nonlinear exciton-polaritons with a Rabi splitting of 27 mev,exhibiting large interaction-induced spectral *** asymptotic BIC-like suppression of polariton radiation into the far field toward the BIC wavevector,in combination with effective reduction of the excitonic disorder through motional narrowing,results in small polariton linewidths below 3 *** with a strongly wavevector-dependent Q-factor,this provides for the enhancement and control of polariton–polariton interactions and the resulting nonlinear optical effects,paving the way toward tuneable BIC-based polaritonic devices for sensing,lasing,and nonlinear optics.

关键词： polar nonlinear continuum

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Thermoelectric and electrical characteristics of SmS ceramic samples after exposure to a pulsed magnetic field

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Journal of Rare Earths 2022年第11期40卷 1778-1784,I0004页

作者： ivan volchkov Evgeniy Baskakov vladimir Strelov vladimir Kanevskii FSRC"Crystallography and Photonics"RAS Leninskiy Prospekt 59119333MoscowRussia

Samarium monosulfide(SmS)is a promising material for creating thermoelectric generators(TEG),gas sensors and strain *** the high values of the generated thermo electromotive force(TEMF)(α≈170-350μv/K),methods for increasing the efficiency of TEGs based on SmS are of considerable *** of these methods can be short-term effects of magnetic fields,including pulsed ones,on these *** action of a pulsed magnetic field(PMF)leading to an increase in TEMF(U)of SmS ceramic samples is *** that are not subjected to high frequency currents(HFC)annealing show an increase in UT of 44.54%-62.18%(from 11.9 to 17.2-19.3 mv).The conductivity(σ)of the samples is~22 Q/cm and is insensitive to short-term exposure to a *** that undergo HFC annealing show an increase in Uof 23.47%-41.31%(from 21.3 to 26.3-30.1 mv)after exposure to a *** conductivity of the samples is~15Ω^(-1)/cm and after a short exposure to the PMF is changing nonmo notonically,with an increase in the overall *** difference in the values of Uand a can be explained by presence of an ordered grain structure and a significant amount of the Sm_(2)O_(2)S phase in the samples subjected to HFC *** mechanisms of the observed changes are discussed.

关键词： Rare earths Thermoelectric Electric properties Magnetically induced changes Samarium monosulfide

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Device-based neuromodulation for cardiovascular diseases and patient’s age

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Journal of Geriatric Cardiology 2022年第11期19卷 876-893页

作者： Evgeny N Mikhaylov Nigar Z Gasimova Natalia N Belyaeva Heber ivan Condori Leandro Aleksandr D vakhrushev Evgeny v Shlyakhto Almazov National Medical Research Centre Saint-PetersburgRussia

The autonomic nervous system plays an important role in the pathogenesis of cardiovascular *** aging,autonomic activity changes,and this impacts the physiological reactions to internal and external *** sympathetic and parasympathetic responses seem to decline,reflecting functional and structural changes in nervous *** some investigators suggested that both the sympathetic and parasympathetic activities were suppressed,others found that only the parasympathetic activity was suppressed while the sympathetic activity *** addition,cardiac innervation progressively diminishes with ***,one may suggest that neuromodulation interventions may have different effects,and older age groups can express an attenuated *** article aims to discuss the effect of device-based neuromodulation in different cardiovascular diseases,depending on the patient’s ***,we cover renal denervation,pulmonary artery denervation,baroreceptor activation therapy,vagus nerve stimulation,spinal cord stimulation,ganglionated plexi ablation for the management of arterial and pulmonary hypertension,heart failure,angina and *** results of many clinical studies appeared to be *** view of the low rate of positive findings in clinical studies incorporating neuromodulation approaches,we suggest the underestimation of advanced age as a potential contributing factor to poorer *** of outcomes between different age groups in clinical trials may shed more light on the true effects of neuromodulation when neutral/ambiguous results are obtained.

关键词： stimulation cardiovascular diseases

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Bright trions in direct-bandgap silicon nanocrystals revealed by low-temperature single-nanocrystal spectroscopy

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Light(Science & Applications) 2015年第1期4卷 179-186页

作者： Katerina Kusova ivan Pelant Jan valenta Institute of Physics of the ASCR v.v.i.Cukrovarnicka 1016200 Prague 6Czech Republic Faculty of Mathematics and Physics Charles UniversityKe Karlovu 512116 Prague 2Czech Republic

Strain-engineered silicon nanocrystals(SiNCs)have recently been shown to possess direct ***,we report the observation of a rich structure in the single-nanocrystal photoluminescence spectra of strain-engineered direct-bandgap SiNCs in the temperature range of 9–300 *** relationship between individual types of spectra is discussed,and the numerical modeling of spectral diffusion of the experimentally acquired spectra reveals a common origin for most *** intrinsic spectral shape is shown to be a structure that contains three peaks,approximately 150 mev apart,each of which possesses a Si phonon *** spectral lines,reaching ≤ mev at 20 K,are *** observed temperature dependence of the spectral structure can be assigned to the radiative recombination of positively charged trions,in contrast to several previous reports linking a very similar shape to phonons in the surface capping *** result serves as strong additional support for the direct-bandgap nature of the investigated SiNCs.

关键词： direct bandgap low-temperature single-nanocrystal spectroscopy silicon nanocrystals trions

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Transcatheter treatment of atherosclerotic lesions of the brain complicated by vascular dementia development

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World Journal of Neuroscience 2012年第4期2卷 200-209页

作者： ivan v. Maksimovich Clinic of Cardiovascular Diseases named after Most Holy John Tobolsky Moscow Russia

The research focuses on the effectiveness of transluminal laser revascularization of the brain in the treatment of atherosclerotic lesions accompanied by vascular dementia development. 1125 patients aged from 29 to 81 (average age 75) suffering from various kinds of atherosclerotic lesions of cerebral vessels were examined during the research. The examination plan included: computed tomography of the brain (CT), magnetic resonance imaging (MRI), scintigraphy of the brain (SG), rheoencephalography (REG), cerebral multi-gated angiography (MUGA). 665 (59.11%) patients suffered from diseases accompanied by the development of vascular dementia. To perform transcatheter treatment, 639 patients were selected: Group 1 (CDR-1)—352 patients, Group 2 (CDR-2)—184 patients, Group 3 (CDR-3)—103 patients. To conduct revascularization of main intracranial arteries high-energy laser systems were used;for revascularization of the distal intracranial branches low-energy laser systems were used. The clinical outcome depended on the severity of dementia and the timing of the intervention. A good clinical outcome in Group 1 was obtained in 281 (79.82%) cases, in Group 2 in 81 (44.02%) cases, in Group 3 in 9 (8.73%) cases. A satisfactory clinical outcome in Group 1 was obtained in 53 (15.34%) cases, in Group 2 in 62 (33.70%) cases, in Group 3 in 31 (30.09%) cases. A relatively satisfactory clinical outcome in Group 1 was obtained in 17 (4.83%) cases, in Group 2 in 41 (22.28%) cases, in Group 3 in 63 (61.16%) cases. No negative effect was observed after the intervention. Evaluating the data obtained it can be concluded that the method of transluminal laser revascularization of cerebral blood vessels is an effective one for the treatment of atherosclerotic lesions of the brain accompanied by dementia.

关键词： Cerebrovascular Disease vascular Dementia Cognitive Impairment Stroke Transcatheter Treatment Laser Revascularization Regeneration

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Differences in Cerebral Angioarchitectonics in Alzheimer’s Disease in Comparison with Other Neurodegenerative and Ischemic Lesions

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World Journal of Neuroscience 2018年第4期8卷 454-469页

作者： ivan v. Maksimovich Clinic of Cardiovascular Diseases Named after Most Holy John Tobolsky Moscow Russia

Introduction: The research focuses on the clinical study of cerebral angioarchitectonics and microcirculation disorders in the development of Alzheimer’s disease (AD) in comparison with other neurodegenerative and ischemic lesions. Materials and methods: 1117 patients with different types and stages of neurodegenerative and ischemic lesions were examined, 93 of whom (8.33%) had different stages of AD—Test Group;1024 (91.67%) had cerebral atherosclerosis, Binswanger disease (BD), vascular Parkinsonism (vP)—Control Group. The examination included definition of CDR, MMSE, cerebral CT, MRI, cerebral sciagraphy (SG), rheoencephalography (REG), morphometric detection of AD stages with TDR, and cerebral multi-gated angiography (MUGA). Results: In all patients with AD, regardless of the disease stage, specific сerebral small vessel disease (CSvD), manifested by dyscirculatory angiopathy of Alzheimer’s type (DAAT), was detected in the temporal and fronto-parietal areas. Conclusions: DAAT is an AD-specific lesion of cerebral microvessels that changes hemodynamics, causes cerebral hypoxia, and contributes to impaired amyloid beta metabolism. The combination of deposition of amyloid beta in the cerebral tissue and vascular wall, as well as specific disorders of microcirculation, cause neurodegeneration and AD development. Patients with other neurodegenerative and ischemic lesions had no DAAT manifestations.

关键词： CSvD cerebral atrophy DAAT. TDR dyscirculatory angiopathy of Alzheimer’s type Alzheimer's disease Tomography Dementia Rating scale dementia

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Possibilities of transcatheter treatment of patients after extensive ischemic stroke

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World Journal of Neuroscience 2013年第3期3卷 171-185页

作者： ivan v. Maksimovich Clinic of Cardiovascular Diseases named after Most Holy John Tobolsky Moscow Russia

The research investigates the efficacy of brain transcatheter laser revascularization in patients who have had extensive ischemic stroke. 1125 patients aged 29 - 81 (average age 75) with cerebral atherosclerosis were examined. The examination plan included: CT brain scan, magnetic resonance imaging (MRI), brain scintigraphy (SG), rheoencephalography (REG), cerebral multi-gated angiography (MUGA), laboratory tests, assessment of severity of dementia (CDR), cognitive impairment (MMSE) and activities of daily living (IB). 93 patients suffered extensive ischemic stroke of whom 7 (7.53%) had 10 - 15 IB points, 25 (26.88%)—20 - 30 IB points, 61 (65.59%)—35 - 45 IB points. 69 patients underwent transcatheter treatment (Test Group). 24 patients underwent conservative treatment (Control Group). High-energy laser systems were used for revascularization of major intracranial arteries;lowenergy laser systems were used for revascularization of distal intracranial branches. Test Group: 67 (97.10%) patients had good immediate angiographic outcome manifested in the restoration of lumen and patency of the affected vessels as well as in collateral revascularization. 12 - 24 months later the following positive trend was observed: 14 (20.59%) patients demonstrated good clinical outcome (IB 90 - 100);26 (38.24%) patients had satisfactory clinical outcome (IB 75 - 85);28 (41.18%) patients showed relatively satisfactory clinical outcome (IB 60 - 70);relatively positive clinical outcome (IB vely satisfactory clinical outcome (IB 60 - 70), relatively positive clinical outcome (IB ved in 20 (83.33%) cases. Evaluating the data obtained, it can be concluded that the method of transluminal laser revascularization of cerebral blood vessels is an effective one for the treatment of extensive ischemic strokes. The effect is maintained for a long time;it causes regression of mental, intellectual and mo

关键词： Extensive Ischemic Stroke Neurological Deficits Post-Stroke Dementia Transcatheter Treatment Laser Revascularization

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