Dark energy and the evolution of spherical overdensities     

Cathy Horellou  Joel Berge † 《Monthly notices of the Royal Astronomical Society》2005,360(4):1393-1400

We use the non-linear spherical model in cold dark matter (CDM) cosmologies with dark energy to investigate the effects of dark energy on the growth of structure and the formation of virialized structures. We consider dark energy models with a constant equation-of-state parameter w . For  −1 < w < −1/3  , clusters form earlier and are more concentrated in quintessence than in ΛCDM models, but they form later and are less concentrated than in the corresponding open model with the same matter density and no dark energy. We point out some confusion in the literature around the expression of the collapse factor (ratio of the radius of the sphere at virialization to that at turnaround) derived from the virial theorem. We use the Sheth & Tormen extension of the Press–Schechter framework to calculate the evolution of the cluster abundance in different models and show the sensitivity of the cluster abundance to both the amplitude of the mass fluctuations, σ₈, and the σ₈– w normalization, selected to match either the cosmic microwave background observations or the abundance of X-ray clusters.  相似文献   

Dark energy and dark matter haloes     

Michael Kuhlen  Louis E. Strigari  rew R. Zentner  James S. Bullock †  Joel R. Primack 《Monthly notices of the Royal Astronomical Society》2005,357(1):387-400

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Identification and quantification of carbonyl-containing α-pinene ozonolysis products using <Emphasis Type="Italic">O</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-butylhydroxylamine hydrochloride     

Stephen R. Jackson  Jason E. Ham  Joel C. Harrison  J. R. Wells 《Journal of Atmospheric Chemistry》2017,74(3):325-338

The yields of carbonyl-containing reaction products from the ozonolysis of α-pinene have been investigated using concentrations of ozone found in the indoor environment ([O₃] ≤ 100 ppb). An impinger was used to collect gas-phase oxidation products in water, where the derivatization agent O-tert-butylhydroxylamine hydrochloride (TBOX) and gas chromatography-mass spectrometry were used to identify carbonyl-containing species. Seven carbonyl-containing products were observed. The yield of the primary product, pinonaldehyde was measured to be 76 %. Using cyclohexane as a hydroxyl radical (?OH) scavenger, the yield of pinonaldehyde decreased to 46 %, indicating the influence secondary OH radicals have on α-pinene ozonolysis products. Furthermore, the use of TBOX, a small molecular weight derivatization agent, allowed for the acquisition of the first mass spectral data of oxopinonaldehyde, a tricarbonyl reaction product of α-pinene ozonolysis. The techniques described herein allow for an effective method for the collection and identification of terpene oxidation products in the indoor environment.  相似文献   

Hydrogeological Decision Analysis: 2. Applications to Ground-Water Contamination   总被引：3，自引：0，他引：3  

Joel Massmann  R. Allan Freeze  Leslie Smith  Tony Sperling  Bruce James 《Ground water》1991,29(4):536-548

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A unified earthquake-resistant design method for steel frames using arma models     

Izuru Takewaki  Joel P. Conte  Stephen A. Mahin  Karl S. Pister 《地震工程与结构动力学》1991,20(5):483-501

The objective of this paper is to develop a unified earthquake-resistant design method for moment-resisting steel frames, including the design earthquake via a dynamic ARMA model. Important features of this design method are: (i) to make it possible to incorporate inherent uncertain features of design earthquakes into the design process itself through the dynamic ARMA model, (ii) to provide a simplified design formula for a preliminary design of moment-resisting steel frames based upon the concept of stiffness-oriented design and (iii) to facilitate the formulation of a new probabilistic multi-objective optimal design problem aimed at finding the design with the minimum level of designer's dissatisfaction. In this optimal design problem, constraints and objectives are handled in a unified manner after a feasible design is obtained. A design example is presented to demonstrate the validity of this unified design method and to examine the convergence of response statistics. Finally, the generality and practicality of this design method are assessed.  相似文献   

Hydrogeological Decision Analysis: 3. Application to Design of a Ground-Water Control System at an Open Pit Mine   总被引：1，自引：0，他引：1  

Tony Sperling  R. Allan Freeze  Joel Massmann  Leslie Smith  Bruce James 《Ground water》1992,30(3):376-389

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Regional mapping of the South Armorican shear zone (Brittany, France) using remotely sensed SPOT imagery     

Herv Ysou  Joel Rolet 《ISPRS Journal of Photogrammetry and Remote Sensing》1990,45(5-6)

The South Armorican shear zone is one of the major occurrences of Variscan basement in Europe. The objectives of the study were to compile a lineament and a structural map from remotely sensed SPOT imagery. Transparent color films, enhanced by high-pass filtering and by stretching color composites, and spatial filtered images were analysed. The major structure mapped corresponds to a dextral transcurrent shear belt in which C and S axes have been described. Late Paleozoic and Tertiary fracturations truncate these structures. The localisation, extension and geometry of granite domes were also precised. Lastly, this study provides a good example of structural interpretation of a moderate-relief terrain using high-resolution SPOT imagery.  相似文献   

Hydrogeological Decision Analysis: 1. A Framework   总被引：6，自引：0，他引：6  

R. Allan Freeze  Joel Massmann  Leslie Smith  Tony Sperling  Bruce James 《Ground water》1990,28(5):738-766

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Comparisons of Three Methods to Determine the Vertical Stratification of Pore Fluids     

Kendrick Taylor  John Hess  Aldo Mazzella  Joel Hayworth 《Ground Water Monitoring & Remediation》1990,10(1):91-95

Three methods were used to investigate the possibility of vertical stratification of the pore fluid in an aquifer. The wells available for the study were fully screened and had a 5cm disturbed annulus around them. The first method used a pump with a straddle packer to isolate a short section of the secreened interval. A tracer test demonstrated that most of the pumped sample came from the well bore, presumably by piping through the disturbed. annulus. The second method used induction logs to measure the formation electrical conductivity as a function of depth. Due to the presence of clays and an inability to obtain porosity information, it was not possible to determine the pore fluid electrical conductivity using induction logs. A third method, dilution sampling, was developed that used a straddle packer to isolate a segment of the well screen. A tracer was injected into the packed-off segment, and the tracer concentration in the well was monitored. The tracer was removed from the packed-off segment by dilution and advection by ground water. When the tracer was completely removed from the packed-off segment, the fluid in the segment was considered to be representative of the adjacent pore fluid. Only the dilution sampling method determined unambiguously that the pore fluid was not stratified.  相似文献   

Cloud cover climatologies in the Mediterranean obtained from satellites,surface observations,reanalyses, and CMIP5 simulations: validation and future scenarios     

Aaron Enriquez-Alonso  Arturo Sanchez-Lorenzo  Josep Calbó  Josep-Abel González  Joel R. Norris 《Climate Dynamics》2016,47(1-2):249-269

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