检索结果-南通市图书馆

hILBERT-DIRAC OPERATORS IN CLIFFORD ANALYSIS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2005年第1期26卷 1-14页

作者： F.BRACKX h.DE SChEPPER Clifford Research Group Department of Mathematical Analysis Faculty of EngineeringGhent UniversityGalglaan 2B-9000 GentBelgiumClifford Research Group Department of Mathematical AnalysisFaculty of EngineeringGhent UniversityGalglaan 2B-9000 GentBelgium

Around the central theme of 'square root' of the Laplace operator it is shown that the classical Riesz potentials of the first and of the second kind allow for an explicit expression of so-called hilbert-Dirac convolu... 详细信息

关键词：希尔伯特变换克里佛德分布迪拉克算子黎兹位势

Entanglement and Other Nonclassical Properties of Two Two-Level Atoms Interacting with a Two-Mode Binomial Field: Constant and Intensity-Dependent Coupling Regimes

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2015年第10期64卷 439-446页

作者： M.K.Tavassoly h.hekmatara Atomic and Molecular Group Faculty of Physics Yazd University Photonic Research Group Engineering Research Center Yazd University The Laboratory of Quantum Information Processing Yazd University

In this paper, we consider the interaction between two two-level atoms and a two-mode binomial field with a general intensity-dependent coupling regime. The outlined dynamical problem has explicit analytical solution, by which we can evaluate a few of its physical features of interest. To achieve the purpose of the paper, after choosing a particular nonlinearity function, we investigate the quantum statistics, atomic population inversion and at last the linear entropy of the atom-field system which is a good measure for the degree of entanglement. In detail, the effects of binomial field parameters, in addition to different initial atomic states on the temporal behavior of the mentioned quantities have been analyzed. The results show that, the values of binomial field parameters and the initial state of the two atoms influence on the nonclassical effects in the obtained states through which one can tune the nonclassicality criteria *** intensity-dependent coupling function equal to 1 reduces the results to the constant coupling case. By comparing the latter case with the nonlinear regime, we will observe that the nonlinearity disappears the pattern of collapse-revival phenomenon in the evolution of Mandel parameter and population inversion(which can be seen in the linear case with constant coupling), however, more typical collapse-revivals will be appeared for the cross-correlation function in the nonlinear case. Finally, in both linear and nonlinear regime, the entropy remains less than(but close to) 0.5. In other words the particular chosen nonlinearity does not critically affect on the entropy of the system.

关键词： Jaynes–Cummings model atom-field interaction two-m

Influence of Non-Maxwellian Particles on Dust Acoustic waves in a Dusty Magnetized Plasma

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2013年第11期60卷 615-622页

作者： M.Nouri Kadijani h.Zareamoghaddam Young Researchers and Elite Club Kashmar Branch Islamic Azad University

In this paper an investigation into dust acoustic solitary waves(DASws) in the presence of superthermal electrons and ions in a magnetized plasma with cold dust grains and trapped electrons is discussed. The dynamic of both electrons and ions is simulated by the generalized Lorentzian(κ) distribution function(DF). The dust grains are cold and their dynamics are studied by hydrodynamic equations. The basic set of fluid equations is reduced to modified Korteweg-de Vries(mKdV) equation using Reductive Perturbation Theory(RPT). Two types of solitary waves, fast and slow dust acoustic soliton(DAS) exist in this plasma. Calculations reveal that compressive solitary structures are possibly propagated in the plasma where dust grains are negatively(or positively) charged. The properties of DASs are also investigated numerically.

关键词：磁化等离子体尘埃声波麦克斯韦流体动力学方程粒子尘土尘埃颗粒分布函数

Method for the determination of polonium-210 in tea samples using response surface methodology(RSM)

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2019年第3期30卷 75-81页

作者： Sermin ?am Kaynar ümit h.Kaynar Physics Department Faculty of Science and Letters Manisa Celal Bayar University Science Education Faculty of Education Manisa Celal Bayar University

The method based on solvent parameters(mass,cycle of acidification, and autodeposition time), combined with response surface methodology(RSM) modeling and optimization, has been developed for maximizing ^(210)Po activity in tea samples, as observed by an alpha spectrometer. RSM based on 3-factor and 5-level composite center design was used to obtain the optimal combination of solvent conditions. As solvent parameters for ^(210)Po activity, different masses(0.5, 0.75, 1, 1.5, and 2 g), different cycles of acidification(2, 3, 4, 5, and 6 times), and different autodeposition times(2, 3, 4, 5, and 6 h) were studied. The 3D response surface plot and the contour plot derived from the mathematical models were used to determine the optimal conditions. According to the obtained results, the experimental value of ^(210)Po activity was in good agreement(R^2=0.96) with the value predicted by the model. we found a favorable effect of mass on the ^(210)Po activity(p\0.05).

关键词： ^210Po activity Tea Response surface methodology

Enamel biomimetics—fiction or future of dentistry?

在线全文

学校读者我要写书评

暂无评论

International Journal of Oral Science 2019年第1期11卷 1-9页

作者： Mirali Pandya Thomas G.h.Diekwisch Center for Craniofacial Research and Diagnosis Texas A&M College of Dentistry

Tooth enamel is a complex mineralized tissue consisting of long and parallel apatite crystals configured into decussating enamel rods. In recent years, multiple approaches have been introduced to generate or regenerate this highly attractive biomaterial characterized by great mechanical strength paired with relative resilience and tissue compatibility. In the present review, we discuss five pathways toward enamel tissue engineering,(i) enamel synthesis using physico-chemical means,(ii) protein matrix-guided enamel crystal growth,(iii) enamel surface remineralization,(iv) cell-based enamel engineering, and(v) biological enamel regeneration based on de novo induction of tooth morphogenesis. So far, physical synthesis approaches using extreme environmental conditions such as ph, heat and pressure have resulted in the formation of enamel-like crystal *** methods relying on enamel proteins as templating matrices have aided the growth of elongated calcium phosphate crystals. To illustrate the validity of this biochemical approach we have successfully grown enamel-like apatite crystals organized into decussating enamel rods using an organic enamel protein matrix. Other studies reviewed here have employed amelogeninderived peptides or self-assembling dendrimers to re-mineralize mineral-depleted white lesions on tooth surfaces. So far, cell-based enamel tissue engineering has been hampered by the limitations of presently existing ameloblast cell lines. Going forward, these limitations may be overcome by new cell culture technologies. Finally, whole-tooth regeneration through reactivation of the signaling pathways triggered during natural enamel development represents a biological avenue toward faithful enamel regeneration. In the present review we have summarized the state of the art in enamel tissue engineering and provided novel insights into future opportunities to regenerate this arguably most fascinating of all dental tissues.

关键词： complex mineralized Biochemical methods

Torsional Characteristics of Single walled Carbon Nanotube with water Interactions by Using Molecular Dynamics Simulation

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2014年第3期6卷 268-279页

作者： V.Vijayaraghavan C.h.wong School of Mechanical and Aerospace Engineering Nanyang Technological University

The torsional characteristics of single walled carbon nanotube(SwCNT) with water interactions are studied in this work using molecular dynamics simulation method. The torsional properties of carbon nanotubes(CNTs) in a hydrodynamic environment such as water are critical for its key role in determining the lifetime and stability of CNT based nano-fluidic devices. The effect of chirality, defects and the density of water encapsulation is studied by subjecting the SwCNT to torsion. The findings show that the torsional strength of SwCNT decreases due to interaction of water molecules and presence of defects in the SwCNT. Additionally,for the case of water molecules encapsulated inside SwCNT, the torsional response depends on the density of packing of water molecules. Our findings and conclusions obtained from this paper is expected to further compliment the potential applications of CNTs as promising candidates for applications in nano-biological and nano-fluidic devices.

关键词： Carbon nanotube water interaction Torsion water encapsulation Nano-fluid Molecular dynamics

Serologic, endoscopic and pathologic findings in pediatric celiac disease: A single center experience in a low/middle income country

在线全文

学校读者我要写书评

暂无评论

world Journal of Clinical Pediatrics 2022年第3期11卷 295-306页

作者： hala h Mansour Nabil A Mohsen Mortada hF El-Shabrawi Somia M Awad Dalia Abd El-Kareem Department of Pediatrics Faculty of Medicine Kasr Al AinyCairo UniversityCairo 12411Egypt Department of Pathology Cairo UniversityCairo 11562Egypt

BACKGROUND Studies in Africa,Asia,and Latin America are needed to provide a comprehensive picture of the global incidence of celiac disease(CD).AIM To describe the serology,endoscopic and histological findings in typical and atypical presentations of pediatric CD at a tertiary referral hospital in an African low/middle income country(LMIC).METhODS This observational study was conducted on 199 patients with CD from 2010 to *** patients were divided into typical and atypical groups according to the presenting symptoms including 120 and 79 patients ***,upper gastrointestinal endoscopy with duodenal biopsy were performed for patients who had symptoms suggestive of *** severity of the intestinal damage was graded according to the histo-pathologic Marsh-Oberhuber *** Chronic diarrhea was the main intestinal presentation in the typical *** was the most common extraintestinal symptom in both the typical and atypical ***-Oberhuber type 3b and 3c was significantly higher in the seropositive patients with a P value of 0.007.A significant correlation was observed between the histological grade of the biopsied duodenal mucosa and the clinical presentation(Pwas significantly higher in the atypical group(P valuehough typical CD was observed in 120 patients in this study,the clinical variability of the condition was frequently *** only was a significant predictor for the appearance of atypical ***,CD presentations in LMIC are not different from industrialized countries.

关键词： Typical Atypical celiac disease Celiac serology Marsh-Oberhuber histopathology

Viral evasion of DNA-stimulated innate immune responses

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2017年第1期14卷 4-13页

作者： Maria h Christensen Sфren R Paludan Department of Biomedicine Aarhus University Aarhus DK-8000 Denmark Aarhus Research Center for Innate Immunology Aarhus University Aarhus DK-8000 Denmark

Cellular sensing of virus-derived nucleic acids is essential for early defenses against virus infections. In recent years, the discovery of DNA sensing proteins, including cyclic GMP-AMP synthase （cGAS） and gamma-interferon- inducible protein （IFI16）, has led to understanding of how cells evoke strong innate immune responses against incoming pathogens carrying DNA genomes. The signaling stimulated by DNA sensors depends on the adaptor protein STING （stimulator of interferon genes）, to enable expression of antiviral proteins, including type I interferon. To facilitate efficient infections, viruses have evolved a wide range of evasion strategies, targeting host DNA sensors, adaptor proteins and transcription factors. In this review, the current literature on virus-induced activation of the STING pathway is presented and we discuss recently identified viral evasion mechanisms targeting different steps in this antiviral pathway.

关键词： DNA sensing evasion innate immunology STING

Key drivers of ecosystem recovery after disturbance in a neotropical forest Long-term lessons from the Paracou experiment, French Guiana

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystems 2018年第1期5卷 13-27页

作者： bruno hérault camille piponiot cirad umr ecofog (agro paristech cnrs inra université des antillesuniversité de la guyane) campus agronomique97310 kouroufrench inphb (institut national polytechnique félix houphouet boigny) yamoussoukroivorycoast université de la guyane umrecofog(agro paristech cirad cnrs inra université des antilles) campus agronomique97310 kouroufrench guianafrance

Background： Natural disturbance is a fundamental component of the functioning of tropical rainforests let to natural dynamics, with tree mortality the driving force of forest renewal. with ongoing global （i.e. land-use and climate） changes, tropical forests are currently facing deep and rapid modifications in disturbance regimes that may hamper their recovering capacity so that developing robust predictive model able to predict ecosystem resilience and recovery becomes of primary importance for decision-making：（i） Do regenerating forests recover faster than mature forests given the same level of disturbance？（ii） is the local topography an important predictor of the post-disturbance forest trajectories？（iii） Is the community functional composition, assessed with community weighted-mean functional traits, a good predictor of carbon stock recovery？（iv） how important is the climate stress （seasonal drought and/or soil water saturation） in shaping the recovery trajectory？ Methods： Paracou is a large scale forest disturbance experiment set up in 1984 with nine 6.25 ha plots spanning on a large disturbance gradient where 15 to 60% of the initial forest ecosystem biomass were removed. More than 70,000 trees belonging to ca. 700 tree species have then been censused every 2 years up today. Using this unique dataset, we aim at deciphering the endogenous （forest structure and composition） and exogenous （local environment and climate stress） drivers of ecosystem recovery in time. To do so, we disentangle carbon recovery into demographic processes （recruitment, growth, mortality fluxes） and cohorts （recruited trees, survivors）. Results： Variations in the pre-disturbance forest structure or in local environment do not shape significantly the ecosystem recovery rates. Variations in the pre-disturbance forest composition and in the post-disturbance climate significantly change the forest recovery trajectory. Pioneer-rich forests have slower recovery rates than assemblages of lat

关键词： Ecosystem modeling Tropical forests Carbon fluxes Ecological resilience Climate change Amazonia