检索结果-南通市图书馆

High resolution sequence stratigraphy of the Mishrif Formation(Cenomanian-Early Turonian)at zubair oilfield(al-rafdhiah dome),southern Iraq

在线全文

学校读者我要写书评

暂无评论

Petroleum Research 2024年第1期9卷 61-71页

作者： Aymen A.Lazim Maher J.Ismail Maher M.Mahdi Geoscience Department Zubair Field Operation DivisionBasra Oil CompanyIraq Basrah Oil Company WQ1 FODBasrahIraq University of Basrah College of ScienceGeology Dept.BasrahIraq

The Mishrif Formation(Cenomanian-E Turonian)is one of the most important geological formations in the Middle East and Iraq because it contains enormous petroleum *** is considered to be the first reservoir in the region,and is still being studied because of its economic *** carbonate of the Mishrif Formation derives from a variety of depositional settings,including mid-ramp,shoal,lagoon,and *** five main microfacies discussed in this paper are wackestone,packstone,grainstone,floatstone,and *** most frequent fossilised components found in the Mishrif Formation are rudists,benthic foraminifera,echinoderms,burrows molluscs,and *** to the microfacies and analysed wireline log data,the sequence stratigraphy of the studied formation is composed of two regression *** parasequences of transgressive-regressive cycles make up the depositional sequence of the Mishrif *** standard depositional environments seem to demonstrate a gradual regression,beginning with a short period of the outer ramp,then a steady period of the mid-ramp,and ending in the intertidal ***,the study recorded two regional maximum flooding surfaces:K-135 and *** former is present in the lowermost part of the formation,while the other lies in the *** study shows a close relationship between facies(environments)and hydrocarbon *** increased accumulation focuses on the lower part of the studied formation,and seems to be lower in the upper part of the formation as a result of changes in the environment of deposition.

关键词： Mishrif formation Cenomanian Sequence stratigraphy Zubair oilfield Iraq

BIFURCATION OF A CLASS OF CODIMENSION-TWO NONLINEAR HIGHER ORDER SYSTEM

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

Annals of Differential Equations 2003年第3期19卷 402-410页

作者：脱秋菊李学敏 Shandong Finance Institute Jinan 250014 dept. of maih. Shandong Normal University Jinan 250014

We discuss a kind of codimension-tvro nonlinear higher order system, by normai form theory the system can be reduced into system equivalent toBogdanov, Takens, Carr have been studied it's local bifurcations for n - 2, after that, Wang Mingshu, Luo Dingjun, Li Jibin, Wang Xian and others studied the global bifurcations for n = 3. In this paper, we study the bifurcations for n - 4, and give all the local bifurcation curves of the system.

关键词： nonlinear higher order codimension-two system bifurcation

NEW FAMILIES OF CENTERS AND LIMIT CYCLES FOR POLYNOMIAL DIFFERENTIAL SYSTEMS WITH HOMOGENEOUS NONLINEARITIES

在线全文

学校读者我要写书评

暂无评论

Annals of Differential Equations 2003年第3期19卷 302-317页

作者：李承治李伟固 Jaume Llibre 张芷芬 School of maih. Sciences Peking University Beijing 100871 dept. de Matematiques Universitat Autonoma de Barcelona Bellaterra 08193 Barcelona Spain

We consider the class of polynomial differential equations x = -y+Pn(x,y), y = x + Qn(x, y), where Pn and Qn are homogeneous polynomials of degree n. Inside this class we identify a new subclass of systems having a center at the origin. We show that this subclass contains at least two subfamilies of isochro-nous centers. By using a method different from the classical ones, we study the limit cycles that bifurcate from the periodic orbits of such centers when we perturb them inside the class of all polynomial differential systems of the above form. In particular, we present a function whose simple zeros correspond to the limit cycles vvhich bifurcate from the periodic orbits of Hamiltonian systems.

关键词： limit cycles centers bifurcation

Effect of different drying methods on the amino acids,α-dicarbonyls and volatile compounds of rape bee pollen

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第1期13卷 517-527页

作者： Yanxiang Bi Jiabao Ni Xiaofeng Xue Zidan Zhou Wenli Tian Valérie Orsat Sha Yan Wenjun Peng Xiaoming Fang State Key Laboratory of Resource Insects Institute of Apicultural ResearchChinese Academy of Agricultural SciencesBeijing 100093China College of Engineering China Agricultural UniversityBeijing 100083China Bioresource Engineering dept. McGill UniversitySte-Anne-de-Bellevue QC H9X 3V9Canada

The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and *** this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were *** results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest *** was the dominantα-DCs in RBP and the highest loss was observed after *** were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying ***,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.

关键词： Drying Bee pollen Free amino acids α-Dicarbonyl compounds Volatile compounds

Microbial Growth and Decay: A Commented Review of the Model

在线全文

学校读者我要写书评

暂无评论

Advances in Microbiology 2024年第1期14卷 1-10页

作者： Alberto Schiraldi Formerly at dept. Food Environ. Nutr. Sci. (DeFENS) University of Milan (Italy) Milan Italy

The paper reviews previous publications and reports some comments about a semi empirical model of the growth and decay process of a planktonic microbial culture. After summarizing and reshaping some fundamental mathematical expressions, the paper highlights the reasons for the choice of a suitable time origin that makes the parameters of the model self-consistent. Besides the potential applications to predictive microbiology studies and to effects of bactericidal drugs, the model allows a suitable proxy of the fitness of the microbial culture, which can be of interest for the studies on the evolution across some thousand generations of a Long Term Evolution Experiment.

关键词： Microbial Cultures Model Time Scale Growth and Decay Evolution

Brillouin expanded time-domain analysis based on dual optical frequency combs

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

Light(Science & Applications) 2024年第8期13卷 1534-1544页

作者： Jae Hyeong Youn Kwang Yong Song Sonia Martin-Lopez Miguel Gonzalez-Herraez María R.Fernández-Ruiz dept.of Physics Chung-Ang UniversitySeoulKorea dept.of Electronics Universidad de AlcaláMadridSpain

Brillouin Optical Time-Domain Analysis(BOTDA)is a widely-used distributed optical fiber sensing technology employing pulse-modulated pump waves for local information retrieval of the Brillouin gain or loss *** spatial resolution of BOTDA systems is intrinsically linked to pulse duration,so high-resolution measurements demand high electronic bandwidths inversely proportional to the *** paper introduces Brillouin Expanded Time-Domain Analysis(BETDA)as a modified BOTDA system,simultaneously achieving high spatial resolution and low detection *** two optical frequency combs(OFCs)with different frequency intervals as pump and probe,local Brillouin gain spectra are recorded by their spectral beating traces in an expanded time domain.A 2-cm-long hotspot located in a 230m single-mode fiber is successfully measured in the time domain with a detection bandwidth of less than 100 kHz using dual OFCs with tailored spectral phase,line spacing,and bandwidth.

关键词： pump optical fiber

Seismic risk assessment for developing countries: Pakistan as a case study

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

Earthquake Engineering and Engineering Vibration 2018年第4期17卷 787-804页

作者： Shaukat A.Khan Kypros Pilakoutas Iman Hajirasouliha Reyes Garcia Maurizio Guadagnini dept. of Civil Engineering Abasyn University dept. of Civil and Structural Engineering The University of Sheffield

Modern Earthquake Risk Assessment（ERA） methods usually require seismo-tectonic information for Probabilistic Seismic Hazard Assessment（PSHA） that may not be readily available in developing countries. To bypass this drawback, this paper presents a practical event-based PSHA method that uses instrumental seismicity, available historical seismicity, as well as limited information on geology and tectonic setting. Historical seismicity is integrated with instrumental seismicity to determine the long-term hazard. The tectonic setting is included by assigning seismic source zones associated with known major faults. Monte Carlo simulations are used to generate earthquake catalogues with randomized key hazard parameters. A case study region in Pakistan is selected to demonstrate the effectiveness of the method. The results indicate that the proposed method produces seismic hazard maps consistent with previous studies, thus being suitable for generating such maps in regions where limited data are available. The PSHA procedure is developed as an integral part of an ERA framework named EQRAM. The framework is also used to determine seismic risk in terms of annual losses for the study region.

关键词： recycled concrete frame-shear wall concealed bracings shaking table test nonlinear time-history responseanalysis

Analytical solutions of uniform extended dislocations and tractions over a circular area in anisotropic magnetoelectroelastic bimaterials

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2013年第1期29卷 73-84页

作者： Y.-F. Zhao X.-C. Shang E. Pan dept. of Civil Engineering University of Akron dept. of Applied Mechanics University of Science and Technology

In this paper, we derive the analytical solutions in a three-dimensional anisotropic magnetoelectroelastic bimaterial space subject to uniform extended dislocations and tractions within a horizontal circular area. By virtue of the Stroh formalism and Fourier transformation, the final expression of solutions in the physical domain contains only line integrals over [0, 2π] rather than infinite integrals. As the reduced cases, the half-space and homogeneous full-space solutions can be directly derived from the present solutions. Also, in terms of material domains, the present solutions can be reduced to the piezoelectric, piezomagnetic, purely elastic materials with different symmetries of material prop- erty. To carry out numerical calculations, Gauss quadrature is adopted. In the numerical examples, the effect of different loading locations on the response at the interface is analyzed. It is shown that, when the magnetic traction or electric dislocation is applied, the physical quantities on the interface may not decrease monotonically as the loading area moves away from the interface. The distributions of different in-plane physical quantities on the upper and lower interfaces under various extended horizontal loadings are compared and the differences are discussed. The work presented in this paper can serve as benchmarks for future numerical studies in related research fields.

关键词： Anisotropic bimaterial space. Magnetoelectroe- lastic Extended dislocations Extended tractions Circular loading Analytic solutions

Seismic fragility assessment of existing sub-standard low strength reinforced concrete structures

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2015年第3期14卷 439-452页

作者： Sohaib Ahmad Nicolas Kyriakides Kypros Pilakoutas Kyriacos Neocleous Qaiser uz Zaman dept. of Civil and Structural Engineering University of Sheffield dept. of Civil Engineering and Geomatics Cyprus University of Technology dept. of Civil and Environmental Engineering University of Engineering and Technology

An analytical seismic fragility assessment framework is presented for the existing low strength reinforced concrete structures more common in the building stock of the developing *** realistic modelling of such substandard structures,low strength concrete stress-strain and bond-slip capacity models are included in calibrating material *** capacity parameters are generated stochastically to produce building population and cyclic pushover analysis is carried out to capture inelastic *** period values are evaluated corresponding to each displacement step on the capacity curves and used as seismic demand.A modified capacity demand diagram method is adopted for the degrading structures,which is further used to evaluate peak ground acceleration from back analysis considering each point on the capacity curve as performance *** developing fragility curves,the mean values of peak ground acceleration are evaluated corresponding to each performance point on the series of capacity curves.A suitable probability distribution function is adopted for the secant period scatter at different mean peak ground acceleration values and probability of exceedance of limit states is evaluated.A suitable regression function is used for developing fragility curves and regression coefficients are proposed for different confidence *** curves are presented for a low rise pre-seismic code reinforced concrete structure typical of developing countries.

关键词： analytical fragility damage index non-engineered b