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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 value problem is considered for a singularly perturbed parabolic convection-diffusion equation; we construct a finite difference scheme on α priori （sequentially） adapted meshes and study its convergence. 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 improvement. 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 improving the solution. To solve the discrete problems aimed at the improvement of the solution, we use uniform meshes on the subdomains. The error of the numerical solution depends weakly on the parameter ε. The scheme converges 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 value v = v（K） can be chosen arbitrarily small for suitable K.

关键词： Singular perturbations convection-diffusion problem piecewise-uniform mesh α priori adapted mesh almost ε-uniform convergence

Providing the Quality of Pipes Supplied for the Construction of Oil Pipelines in Arctic Conditions

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China Oil & Gas 2024年第4期31卷 57-64页

作者： Tkachuk Maxim Alexandrovich Nesterov grigory Valerievich Yushin Alexey Alexandrovich Limited Liability Company《Sinarastroykomplekt》 LLC《Sinarastroykomplekt》 Zhejiang Jinggong integration Technology Co.Ltd.

This article discusses the design features of pipes in thermal insulation used in the construction of main and field pipelines in Arctic *** defects that occur during the production,transportation and storage of pipes are *** for repair or prevention of defects are *** information may be useful to Chinese manufacturers and transport companies in order to ensure the possibility of supplying pipes to construction sites in Arctic conditions.

关键词： companies Arctic pipes

Advances in technology for the laboratory diagnosis of individuals with HiV/AiDS coinfected with Mycobacterium tuberculosis

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Biosafety and Health 2024年第3期6卷 133-142页

作者： Jin Sun Xiaoxu Han Hongxia Yan Xin Zhang Taiyi Jiang Tong Zhang Hao Wu grigory Kaminskiy Yingmin Ma Eduard Karamov Bin Su Beijing Key Laboratory for HiV/AiDS Research Clinical and Research Center for Infectious DiseasesBeijing Youan HospitalCapital Medical UniversityBeijing 100069China State Health Organization Tula Regional Center for Control and Prevention of AiDS and infectious Diseases Tula 300002Russia Department of Respiratory and Critical Care Medicine Beijing Youan HospitalCapital Medical UniversityBeijing 100069China Gamaleya National Research Centre for Epidemiology and Microbiology of the Ministry of Health of the Russian Federation Moscow 123098Russia

The high morbidity and mortality rate of individuals with human immunodeficiency virus(HiV)/acquired immunodeficiency syndrome(AiDS)coinfected with Mycobacterium tuberculosis(MTB)is a tough challenge for current global tuberculosis prevention and control ***/MTB coinfection is more complex than a single infection,and the interaction between the two diseases aggravates the deterioration caused by the disease,resulting in increased hospitalizations and *** screening and early diagnosis facilitate the timely initiation of anti-tuberculosis treatment in HiV/MTB coinfected individuals,thereby reducing transmission and the incidence of adverse *** date,pathogenic detection has remained the gold standard for diagnosing tuberculosis,but its sensitivity and specificity are greatly affected by the body's immune status,which limits its application in the diagnosis of HiV/MTB ***,immunology and molecular detection technology has developed *** detection technologies,such as interferon-γ release assays,interferon-gamma inducible protein 10,and GeneXpert MTB/RiF assay have overcome the limitations of traditional detection methods,significantly improved the sensitivity and specificity of tuberculosis diagnosis,and brought new hope to the detection of HiV/MTB *** this article,the principle,scope of application,and latest research progress of relevant detection methods are reviewed to provide a reference for the early diagnosis of HiV/MTB coinfection.

关键词： Human immunodeficiency virus(HiV) Mycobacterium tuberculosis(MTB)coinfection Mycobacterium tuberculosis(MTB) Early diagnosis

On Separable Schur Rings over Abelian Groups

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Algebra Colloquium 2021年第3期28卷 431-440页

作者： grigory Ryabov Sobolev institute of Mathematics NovosibirskRussia Novosibirsk State UniversityNovosibirskRussia

A finite group is said to be weakly separable if every algebraic isomorphism between two 5-rings over this group is induced by a combinatorial *** prove that every abelian weakly separable group only belongs to one of... 详细信息

关键词： isomorphisms Schur rings abelian groups

Analysis of the Caratheodory's Theorem on Dynamical System Trajectories Under Numerical Uncertainty

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iEEE/CAA Journal of Automatica Sinica 2018年第4期5卷 787-793页

作者： Pavel Osinenko grigory Devadze Stefan Streif Automatic Control and System Dynamics Laboratory Technische Universitat Chemnitz09107 ChemnitzGermany iEEE

The current work proposes a new and constructive proof for the Caratheodory's theorem on existence and uniqueness of trajectories of dynamical systems. The key concern is the numerical uncertainty, i.e., the discrepancy between mathematical proofs, algorithms, and their implementations, which may affect the correct functioning of a control system. Due to growing demands on security and compliance with specifications,correctness of the control system functioning is becoming ever more important. Since in both dynamical systems and many control design approaches, one of the central notions is the system trajectory, it is important to address existence and uniqueness of system trajectories in a way which incorporates numerical uncertainty. Constructive analysis is a particular approach to formalizing numerical uncertainty and is used as the basis of the current work. The major difficulties of guaranteeing existence and uniqueness of system trajectories arise in the case of systems and controllers which possess discontinuities in time,since classical solutions to initial value problems do not *** issue is addressed in Caratheodory's theorem. A particular constructive variant of the theorem is proven which covers a large class of problems found in practice.

关键词： Constructive analysis Caratheodory’s theorem dynamical systems

Ci-Property for Decomposable Schur Rings over an Abelian Group

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Algebra Colloquium 2019年第1期26卷 147-160页

作者： istvan Kovacs grigory Ryabov UP iAM University of Primorska Muzejski trg 2 6000 Koper Slovenia UP FAMNiT University of Primorska Glagoljaska 8 6000 Koper Slovenia Sobolev institute of Mathematics Novosibirsk Russia Novosibirsk State University Novosibirsk Russia

A Schur ring over a finite group is said to be decomposable if it is the generalized wreath product of Schur rings over smaller groups. in this paper we establish a sufficient condition for a decomposable Schur ring over the direct product of elementary abelian groups to be a Ci-Schur ring. By using this condition we offer short proofs for some known results on the Ci-property for decomposable Schur rings over an elementary abelian group of rank at most 5.

关键词： isomorphism Ci-group Schur ring

Peliosis hepatis complicated by portal hypertension following renal transplantation

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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 liver peliosis,characterized by an increased proliferative ***,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 Survivin Epithelial-mesenchymal transition

Pendulum-type laser strainmeter

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

作者： grigory ivanovich Dolgikh V.i.il'ichev Pacific Oceanological institute of the Far Eastern Branch Russian Academy of Sciences

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

关键词： Amplitude-frequency characteristic Classical-type laser strainmeter Elastic wave infrasound Pendulum-type laser strainmeter

Assessing workability of greased bearings after long-term storage

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Friction 2019年第5期7卷 489-496页

作者： Michael VARENBERG 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 developed a technique to assess the workability of sealed-for-life greased rolling bearings after a long-term storage. in this framework, we devised a model of equivalent 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. However, a proper running-in can substantially deter the ageing-driven degradation of the bearings.

关键词： grease lubrication ball bearings thermal ageing lubricant degradation

Clinical significance of mesenteric panniculitis-like abnormalities on abdominal computerized tomography in patients with malignant neoplasms

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World Journal of Gastroenterology 2016年第48期22卷 10601-10608页

作者： Eli D Ehrenpreis grigory Roginsky Richard M Gore University of Chicago Center for the Study of Complex Diseases Gastroenterology North Shore University Health System Highland Park Hospital Department of Radiology North Shore University HealthS ystem

AiM To clarify the association of malignancy with mesenteric panniculitis-like changes on computed tomography(CT).METHODS All abdominal CT scans performed at North Shore University HealthS ystem showing mesenteric panniculitis from January 2005 to August 2010 were identified in the Radnet(Rad Net Corporation, Los Angeles, CA) database. Patients with a new or known diagnosis of a malignancy were included for this analysis. Longitudinal clinical histories were obtained from electronic medical *** in total, 147794 abdominal CT scans were performed during the study period. Three hundred and fiftynine patients had mesenteric panniculitis(MP)-like abnormalities on their abdominal CT. Of these patients, 81 patients(22.6%) had a known history of cancer at the time of their CT scan. Nineteen(5.3%) had a new diagnosis of cancer in concurrence with their CT, but the majority of these(14/19, 74%) were undergoing CT as part of a malignancy evaluation. Lymphomas were the most common cancers associated with MPlike findings on CT(36 cases, 36%), with follicular lymphoma being the most frequent subtype(17/36). A variety of solid tumors, most commonly prostate(7) and renal cell cancers(6) also were seen. CT follow up was obtained in 56 patients. Findings in the mesentery were unchanged in 45(80%), worsened in 6(11%), and improved in 5 patients(9%). Positron emission tomography(PET) scans performed in 44 patients only showed a positive uptake in the mesenteric mass in 2 patients(5%). CONCLUSiON A new diagnosis of cancer is uncommon in patients with CT findings suggestive of MP. MP-like mesenteric abnormalities on CT generally remain stable in patients with associated malignancies. PET scanning is not recommended in the evaluation of patients with mesenteric panniculitis-like findings on CT.

关键词： Panniculitis Peritoneal X ray Neoplasms Computed tomography Small intestine Misty mesentery Lymphoma Tomography Positron emission tomography