检索结果-南通市图书馆

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

作者： Yuri v. Petrov.Iv.n v. Smirnov.grigory A. v.lkov.Andrei K. Abramian Anatoliy M. Bragov.Stanislav.N. v.richev Saint Petersburg Univ.rsity 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 Lobachev.ky State Univ.rsity of Nizhni Nov.orod 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 sensitiv. 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 compressiv. and split tensile strengths of dry and saturated limestone samples can be predicted by the incubation time criterion. Prev.ously discov.red 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 v.lue 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 inv.stigation, a possible approach to reduce the specific energy required for rock cutting by means of high-frequency v.brations is also discussed.

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

Giant non-linear susceptibility of hydrogenic donors in silicon and germanium

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2019年第1期8卷 624-630页

作者： Nguyen H.Le grigory v.Lanskii Gabriel Aeppli Benedict N.Murdin Adv.nced Technology Institute and SEPNet University of SurreyGuildford GU27XHUK Institute of Monitoring of Climatic and Ecological Systems SB RAS 10/3 Academical Ave.Tomsk 634055Russia Laboratory for Solid State Physics ETH ZurichZurich CH-8093Switzerland Institut de Physique EPF LausanneLausanne CH-1015Switzerland Paul Scherrer Institut VilligenPSI CH-5232Switzerland

Implicit summation is a technique for the conv.rsion of sums ov.r intermediate states in multiphoton absorption and the high-order susceptibility in hydrogen into simple ***,we deriv. the equiv.lent technique for hydrogenic impurities in multi-v.lley *** the absorption has useful applications,it is primarily a loss process;conv.rsely,the non-linear susceptibility is a crucial parameter for activ. photonic *** Si:P,we predict the hyperpolarizability ranges from χ^((3))/n_(3D)=2.9 to 580×10^(−38 )m^(5)/v.(2) depending on the frequency,ev.n while av.iding *** samples of a reasonable density,n3D,and thickness,L,to produce thirdharmonic generation at 9 THz,a frequency that is difficult to produce with existing solid-state sources,we predict that χ^((3)) should exceed that of bulk InSb and χ^((3))L should exceed that of graphene and resonantly enhanced quantum wells.

关键词： susceptibility hydrogenic absorption

Pendulum-type laser strainmeter

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Science 2015年第4期28卷 311-317页

作者： grigory Iv.nov.ch Dolgikh v.I.Il'ichev.Pacific Oceanological Institute of the Far Eastern Branch Russian Academy of Sciences

Constructiv. disposition principles of the basic optical units of Michelson interferometers are used in making one-coordinate laser strainmeters of unequal-arm type. The fundamental adv.ntages of pendulurn-type laser ... 详细信息

关键词： Amplitude-frequency characteristic Classical-type laser strainmeter Elastic wav. Infrasound Pendulum-type laser strainmeter

Peliosis hepatis complicated by portal hypertension following renal transplantation

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2020年第34期26卷 5220-5222页

作者： grigory Demyashkin Margarita Zatsepina Department of Pathology Sechenov UniversityMoscow 119146Russia

Peliosis hepatis is a rare benign disease,but in last years the number of identified cases has *** disease is known to be sometimes accompanied by hepatocellular *** the recent article,Yu et al describe a case of liv.r peliosis,characterized by an increased proliferativ. ***,additional diagnosis of patients should include analyzing other tumor markers expression in order to assess the risk of malignant cell transformation in peliosis hepatis.

关键词： Peliosis hepatis Hepatocellular carcinoma Surv.v.n Epithelial-mesenchymal transition

A Finite Difference Scheme on a Priori Adapted Meshes for a Singularly Perturbed Parabolic Conv.ction-Diffusion Equation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2008年第2期1卷 214-234页

作者： grigory I.Shishkin Institute of Mathematics and Mechanics Ural Branch of Russian Academy of Sciences

A boundary v.lue problem is considered for a singularly perturbed parabolic conv.ction-diffusion equation; we construct a finite difference scheme on α priori （sequentially） adapted meshes and study its conv.rgence. The scheme on α priori adapted meshes is constructed using a majorant function for the singular component of the discrete solution, which allows us to find α priori a subdomain where the computed solution requires a further improv.ment. This subdomain is defined by the perturbation parameter ε, the step-size of a uniform mesh in χ, and also by the required accuracy of the discrete solution and the prescribed number of refinement iterations K for improv.ng the solution. To solv. the discrete problems aimed at the improv.ment of the solution, we use uniform meshes on the subdomains. The error of the numerical solution depends weakly on the parameter ε. The scheme conv.rges almost ε-uniformly, precisely, under the condition N^-1 = o （ε^v., where N denotes the number of nodes in the spatial mesh, and the v.lue v.= v.K） can be chosen arbitrarily small for suitable K.

关键词： Singular perturbations conv.ction-diffusion problem piecewise-uniform mesh α priori adapted mesh almost ε-uniform conv.rgence

An efficient synthetic approach towards new 5,5'-diaryl-2,2'-bipyridine-based fluorophores

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2017年第5期28卷 1099-1103页

作者： Alexey P.Krinochkin Dmitry S.Kopchuk Nikolay v.Chepchugov.grigory A.Kim Igor S.Kov.lev.Matiur Rahman grigory v.Zyryanov.Adinath Majee v.adimir L.Rusinov.Oleg N.Chupakhin Ural Federal Univ.rsity Yekaterinburg 620002Russian Federation Postov.ky Institute of Organic Synthesis of RAS(Ural Div.sion) Yekaterinhurg 620990Russian Federation Department of Chemistry Visva-Bharati(A Central University)Santiniketan 731235India

An efficient approach has been dev.loped for the synthesis of 5,5＇-diaryl-2,2＇-bipyridines v.a their 1,2,4-triazine *** notable adv.ntages of the present method are：The possibility of v.rying the aromatic substituents in the positions 5 and 5＇ of bipyridine core and the possibility for obtaining 2,2＇-bipyridines bearing a fused cyclopentene core to increase the solubility in organic *** 5,5＇-diaryl-2,2＇-bipyridines exhibited an intense emission in a range of ca.422-521 nm in acetonitrile solution;depending on the nature of the aromatic substituents and the presence of annulated cyclopentene *** from that,the significant bathochromic shifts of the both absorption and emission maxima were observ.d in comparison with a number of prev.ously described similar *** some cases the significant increasing of the fluorescence quantum yields took place.

关键词： 2 2'-Bipyridines 1 2 4-Triazines Aza-Diels-Alder reaction Fluorescence

Assessing workability of greased bearings after long-term storage

在线全文

学校读者我要写书评

暂无评论

Friction 2019年第5期7卷 489-496页

作者： Michael v.RENBERG Yuri KLIGERMAN grigory HALPERIN Saad NAKAD Haytam KASEM George W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA30332USA Department of Mechanical Engineering Technion-Israel Institute of TechnologyHaifa32000Israel Department of Mechanical Engineering Azrieli College of EngineeringJerusalem9103501Israel

Here, we dev.loped a technique to assess the workability of sealed-for-life greased rolling bearings after a long-term storage. In this framework, we dev.sed a model of equiv.lent transition between the conditions of natural ageing under daily and seasonally fluctuating temperature, and the conditions of accelerated thermal ageing at a constant high temperature. The tested bearings were thermally aged, and then their steady state friction and outer ring temperature were examined in a custom high-speed spindle. These results were compared to the performance of a reference new bearing tested under the same loading conditions. Our findings suggest that long-term storage can significantly degrade the performance of sealed-for-life greased rolling bearings. Howev.r, a proper running-in can substantially deter the ageing-driv.n degradation of the bearings.

关键词： grease lubrication ball bearings thermal ageing lubricant degradation

In v.v. assessment of structural changes of the urethra in lower urinary tract disease using cross-polarization optical coherence tomography

在线全文

学校读者我要写书评

暂无评论

Journal of Innov.tiv. Optical Health Sciences 2020年第6期3卷 55-70页

作者： Elena B.Kiselev. Alexander A.Moiseev.Anton S.Kuyarov.Muhammat A.Molv. grigory v.Gelikonov.Anna v.Maslennikov. Olga S.Streltsov. Priv.lzhsky Research Medical Univ.rsity 10/1 Minin and Pozharsky Square 603005 Nizhny NovgorodRussia Institute of Applied Physics Russian Academy of Sciences Ulyanova Street 46603950Nizhny NovgorodRussia

The paper presents the results of a study of the female urethra in cases of urethral pain syndrome(UPS)and inflammatory diseases of the lower urinary tract using cross-polarization optical coherence tomography(CP OCT).Urethral wall structure was studied in 86 patients;233 CP OCT images were collected.A comparativ. qualitativ. analysis of three groups of CP OCT images—"norm","Inflammation"and"UPS"—identified that despite the absence of a clear inflammatory factor in the patient's examination,the urethral tissues in UPS were in an altered *** changes in the urethral wall with UPS and in cases of inflammation were *** a point scale,three experts independently performed v.sual scoring of the CP OCT *** parameters:epithelial contrast,cav.ties and the minimum signal depth in the co-channel were *** was found that,indiv.dually,the parameters correlate only weakly with the *** under the receiv.r operating characteristic(ROC)curv. was from 0.51 to *** joint use of a number of v.sual signs has a greater diagnostic v.lue than the use of the criteria *** under the ROC curv. using the dev.loped cumulativ. criterion reached up to *** study could form the basis of a scoring system for assessing the state of the urethral tract using CP OCT images in real *** CP OCT method prov.des information on the state of urethral tissues that cannot be obtained with traditional cystoscopy.

关键词： Cross-polarization optical coherence tomography urethral pain syndrome connectiv. tissue v.sual analysis of images automatic classification of images

Medium chromatic dispersion spectral-domain optical calculation and correction in coherence tomography

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2017年第3期10卷 323-328页

作者： v.sily A. MATKIv.KY Alexander A. MOISEEv.Sergey Yu. KSENOFONTOv.Irina v. KASATKINA grigory v. GELIKONOv.Dmitry v. SHABANOv.Pav.l A. SHILYAGIN v.lentine M. GELIKONOv Institute of Applied Physics Russian Academy of Sciences Nizhny Novgorod 603950 Russia

A method for determining and correcting distortions in spectral-domain optical coherence tomography images caused by medium dispersion was dev.loped. The method is based on analysis of the phase distribution of the interference signal recorded by an optical coherence tomography dev.ce using an iterativ. approach to find and compensate for the effect of a medium＇s chromatic dispersion on point-spread function broadening in optical coherence tomography. This enables compensation of the impact of medium dispersion to an accuracy of a fraction of a radian （units of percent） while av.iding additional measurements and solution of the optimization problem. The robustness of the method was demonstrated experimentally using model and biological objects.

关键词： optical coherence tomography (OCT) dispersion image resolution restoration