检索结果-南通市图书馆

Science China Mathematics 2019年第6期62卷 1029-1040页

作者： Annalisa Baldi bruno Franchi Pierre Pansu Dipartimento di Matematica Università di Bologna Laboratoire de Mathématiques d'Orsay Université Paris-Sud CNRSUniversité Paris-Saclay

In this paper, we prove Poincaré and Sobolev inequalities for differential forms in L^1(R^n). The singular integral estimates that it is possible to use for L^p, p > 1, are replaced here with inequalities which go ba... 详细信息

关键词： differential forms Sobolev-Poincaré inequalities homotopy formula

A Recursive Basis for Primitive Forms in Symplectic Spaces and Applications to Heisenberg Groups

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2016年第3期32卷 265-285页

作者： Annalisa BALDI Marilena BARNABEI bruno FRANCHI Dipartimento di Matematica Piazza di Porta S.Donato 540126 BolognaItaly

This paper is divided in two parts： in Section 2, we define recursively a privileged basis of the primitive forms in a symplectic space（V^（2n）, ω）. Successively, in Section 3, we apply our construction in the setting of Heisenberg groups H^n, n ≥ 1, to write in coordinates the exterior differential of the so-called Rumin＇s complex of differential forms in H^n.

关键词： Symplectic manifolds differential forms Heisenberg groups combinatorial functions

Risk for gastric neoplasias in patients with chronic atrophic gastritis:A critical reappraisal

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第12期18卷 1279-1285页

作者： Lucy Vannella Edith Lahner bruno Annibale Dipartimento Medico-Chirurgico di Scienze Cliniche Tecnobiomediche e Medicina TraslazionaleSant'Andrea HospitalSchool of MedicineUniversity Sapienza

Chronic atrophic gastritis （CAG） is an inflammatory condition characterized by the loss of gastric glandular structures which are replaced by connective tissue （non-metaplastic atrophy） or by glandular structures inappropriate for location （metaplastic atrophy）. Epidemiological data suggest that CAG is associated with two different types of tumors： Intestinal-type gastric cancer （GC） and type I gastric carcinoid （T I GC）. The pathophysiological mechanisms which lead to the development of these gastric tumors are different, It is accepted that a multistep process initiating from Helico- bacterpylori-related chronic inflammation of the gastric mucosa progresses to CAG, intestinal metaplasia, dysplasia and, finally, leads to the development of GC. The T I GC is a gastrin-dependent tumor and the chronic elevation of gastrin, which is associated with CAG, stimulates the growth of enterochromaffin-like cells with their hyperplasia leading to the development of T I GC. Thus, several events occur in the gastric mucosa before the development of intestinatype GC and/ or T I GC and these take several years. Knowledge ofCAG incidence from superficial gastritis, its prevalence in different clinical settings and possible risk factors as- sociated with the progression of this condition to gastric neoplasias are important issues. This editorial intends to provide a brief review of the main studies regarding incidence and prevalence of CAG and risk factors for the development of gastric neoplasias.

关键词： Chronic atrophic gastritis Gastric neoplasia Intestinal-type gastric cancer Type I gastric carcinoid Prevalence Incidence Risk factors

SYNCHRONIZED PATH FOLLOWING CONTROL OF MULTIPLE HOMOGENOUS UNDERACTUATED AUVS

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 Systems Science & Complexity 2012年第1期25卷 71-89页

作者： Xianbo XIANG Chao LIU Lionel LAPIERRE bruno JOUVENCEL School of Naval Architecture and Ocean Engineering Huazhong University of Science and Technology Department of Robotics LIRMM-CNRS-UMIIUMR 5506161 rue AdaMontpellier Cedex 534095France Department of Robotics LIRMM-CNRSUMR 5506161 rue AdaMontpellier Cedex 534095France

This paper addresses the problem of synchronized path following of multiple homogenous underaetuated autonomous underwater vehicles （AUVs）. The dedicated control laws are categorized into two envelopes： One is steering individual underwater vehicle to track along predefined path, and the other is ensuring tracked paths of multiple vehicles to be synchronized, by means of decentralized speed adaption under the constraints of multi-vehicle communication topology. With these two tasks formulation, geometric path following is built on Lyapunov theory and baekstepping techniques, while injecting helmsman behavior into classic individual path following control. Synchronization of path parameters are reached by using a mixture of tools from linear algebra, graph theory and nonlinear control theory. A simple but effective control design on direct inter-vehicle speed adaption with minimized communication variables, enables the multi-AUV systems to be synchronized and stabilized into an invariant manifold, and all speeds converge to desired assignments as a byproduct. Simulation results illustrate the performance of the synchronized path following control laws proposed.

关键词： Path following synchronization underactuated AUVs.

Heat Transfer in Internal Channel of a Blade:Effects of Rotation in a Trailing Edge Cooling System

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2012年第3期21卷 236-249页

作者： Luca Andrei Antonio Andreini Leonardo Bonanni bruno Facchini Department of Energy Engineering "Sergio Stecco" University of Florence

The aerothermal performance of a trailing edge （TE） internal cooling system of a high pressure gas turbine blade was evaluated under stationary and rotating conditions. The investigated geometry consists of a 30：1 scaled model reproducing a typical wedge shaped discharge duct with one row of enlarged pedestals. The airflow pattern inside the device simulates a highly loaded rotor blade cooling scheme with a 90 [deg] turning flow from the radial hub inlet to the tangential TE outlet. Two different tip configurations were tested, the first one with a completely closed section, the second one with a 5 holes outlet surfaces discharging at ambient pressure. In order to assess rotation effects, a rotating test rig, composed of a rotating ann holding both the PMMA TE model and the instru mentation, was purposely developed and manufactured. A thin Inconel heating foil and wide band Thermochromic Liquid Crystals are used to perform steady state heat transfer measurements on the blade pres sure side. A rotary joint ensures the pneumatic connection between the blower and the rotating apparatus; more over several slip rings are used for both instrumentation power supply and thermocouple connection. A parallel CFD analysis involving steadystate RANS modeling was conducted to allow an insight of the flow field inside the redirecting channel and the interpedestal ducts to better interpret the developing vortical structures. LowReynolds grid clustering permits to integrate up to the wall both the momentum and the thermal boundary layer. Calculations were performed by means of an inhouse developed pressure based solver exploiting the kco SST turbulence model implemented in the framework of the opensource finite volume discretization toolbox OpenFOAM~. Analyzed flow conditions correspond to Reynolds number of 20000 in the hub inlet section and angular speed varies to obtain rotation numbers in the range from 0 to 0.3. The orientation of the rotation axis is orthogonal to the heated s

关键词： heat transfer trailing edge pedestal rotation number OpenFOAM~ CFD TLC thermography

Wire Rope Isolators for Seismic Base Isolation

在线全文

学校读者我要写书评

暂无评论

Sound & Vibration 2018年第5期52卷 2-5页

作者： Claude Prost bruno Abdelnour Sales and Marketing Director of Socitec Products Shock and Vibration Specialist

Tall and slender substation equipment is prone to failure under seismicexcitations. The consequences of such failure can be devastating andlead to weeks or months of lost *** IEEE Std 693-2005 ensures that all substation equipment installedin high seismic areas are designed to withstand earthquakes of aseverity related to that *** are numerous ways to increase the seismic strength of substationequipment and this paper will discuss doing so by base isolation,specifically using wire rope isolators (WRIs).

关键词： seismic Seismic consequences

Lack of specific association between gastric autoimmunity hallmarks and clinical presentations of atrophic body gastritis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2005年第34期11卷 5351-5357页

作者： bruno Annibale Edith Lahner Riccardo Negrini Flavia Baccini Cesare Bordi bruno Monarca Gianfranco Delle Fave Department of Digestive and Liver Disease II School of Medicine University "La Sapienza" Sant'Andrea Hospital Rome Italy Microbiology Department Spedali Civili Brescia Italy Pathology Department University of Parma Parma Italy Hematology Department University "La Sapienza" Sant'Andrea Hospital Rome Italy

AIM： To investigate the possible relationships between gastric autoimmune phenomena and clinical presentations of this disorder, in consecutive atrophic body gastritis patients. METHODS： A total of 140 atrophic body gastritis patients, diagnosed as consecutive outpatients presenting with macrocytic or iron deficiency anemia, or longstanding dyspepsia underwent gastroscopy with antral and body biopsies, assay of intrinsic factor, parietal cells and Helicobacter pylori （ H pylon） antibodies. Gastritis was assessed according to Sydney System. RESULTS： Parietal cell antibodies were equally distributed in all clinical presentations, whereas the positivity of intrinsic factor antibodies （49/140, 35%） was significantly higher in pernicious anemia patients （49.2%） than in iron deficiency （21.1%） and dyspeptic patients （27.8%）. No specific pattern of autoantibodies was related to the clinical presentations of atrophic body gastritis. A positive correlation was obtained between the body atrophy score and the intrinsic factor antibody levels （r=0.2216, P=0.0085）. Associated autoimmune diseases were present in 25/140 （17.9%） patients, but the prevalence of autoimmune diseases was comparable, irrespective of the clinical presentations. CONCLUSION： The so-called hallmarks of gastric autoimmunity, particularly in intrinsic factor antibody cannot be usefully employed in defining an autoimmune pattern in the clinical presentations of ABG.

关键词： Atrophic body gastritis Intrinsic factor antibodies Helicobacter pylort, Iron deficiency anemia Pernicious anemia

Deep learning tomographic reconstruction through hierarchical decomposition of domain transforms

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Visual Computing for Industry,Biomedicine,and Art 2022年第1期5卷 365-377页

作者： Lin Fu bruno De Man GE Research NY 12309 NiskayunaUSA

Deep learning(DL)has shown unprecedented performance for many image analysis and image enhancement ***,solving large-scale inverse problems like tomographic reconstruction remains challenging for *** problems involve non-local and space-variant integral transforms between the input and output domains,for which no efficient neural network models are readily available.A prior attempt to solve tomographic reconstruction problems with supervised learning relied on a brute-force fully connected network and only allowed reconstruction with a 128^(4)system matrix *** cannot practically scale to realistic data sizes such as 512^(4)and 512^(6)for three-dimensional *** we present a novel framework to solve such problems with DL by casting the original problem as a continuum of intermediate representations between the input and output *** original problem is broken down into a sequence of simpler transformations that can be well mapped onto an efficient hierarchical network architecture,with exponentially fewer parameters than a fully connected network would *** applied the approach to computed tomography(CT)image reconstruction for a 5124 system matrix *** work introduces a new kind of data-driven DL solver for full-size CT reconstruction without relying on the structure of direct(analytical)or iterative(numerical)inversion *** work presents a feasibility demonstration of full-scale learnt reconstruction,whereas more developments will be needed to demonstrate superiority relative to traditional reconstruction *** proposed approach is also extendable to other imaging problems such as emission and magnetic resonance *** broadly,hierarchical DL opens the door to a new class of solvers for general inverse problems,which could potentially lead to improved signal-to-noise ratio,spatial resolution and computational efficiency in various areas.

关键词： Computed tomography Image reconstruction Deep learning Hierarchical

Sustainable intensification of African agriculture:a necessity,but not yet a reality

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 Agricultural Science and Engineering 2020年第4期7卷 383-389页

作者： bruno GÉRARD International Maize and Wheat Improvement Center(CIMMYT) Texcoco 56237Mexico

After decades of well-intentioned and professional research for development,agriculture in sub-Saharan Africa is still dominated by low-input,subsistence food crop production on small,rainfed land holdings using hand *** are the drivers and constraints to development in African agriculture,and how can the region intensify farming in economical and environmentally sustainable ways to satisfy its rapidly rising and shifting food demands?

关键词： Sustainable agriculture shifting

Scintrex CG5 used for superconducting gravimeter calibration

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2018年第3期9卷 197-203页

作者： bruno Meurers Department of Meteorology and Geophysics University of Vienna

The scale factor accuracy of superconducting gravimeters （SG） can be largely improved by a high repetition rate of calibration experiments. At stations where the availability of absolute gravimeters is limited, carefully calibrated spring gravimeters can be used for providing the reference signal assuming the irregular drift is properly adjusted. The temporal stability of the SG scale factor is assessable by comparing the temporal variations of M2 tidal parameters observed at neighboring SG sites or from synthetic tide models. Combining these methods reduces the SG scale factor error to a few 0.1%0. The paper addresses the particular procedure required for evaluating the calibration experiments based on spring gravimeters and presents results obtained at Conrad observatory （Austria）. Comparing the M2 amplitude factor modulation helped to reveal a SG scale factor offset of about 0.2%0 due to re-installation.

关键词： Superconducting gravimeter CG-5 Scintrex gravimeterScale factor Calibration accuracy M2 tidal parameter variation