Ratio Of Sections Research Articles

Search for pair-produced vector-like quarks with the ATLAS detector

The high energy frontier opened by the LHC is allowing us to explore physics scenarios where new physics might lay. The need to go beyond the Standard Model (SM) comes from various unanswered questions such as where does the matter-antimatter asymmetry comes from? What is the nature of Dark Matter? How can the hierarchy problem be solved? The recent discovery of an Higgs-like boson tends to disfavour the existence of a heavy 4th generation of quarks which would change the Higgs SM cross section and branching ratio in a way that is not experimentally observed. At the same time, vector-like quarks become a more compelling possibility due to their important role stabilizing the Higgs boson mass against r adiative corrections. The purpose of this poster is to review the latest results in the searches for pair production of vector-like quarks at the ATLAS experiment.

Illumination uniformity optimization of position-sensitive detector sensing optical system by circular and annular obscurations

In order to increase the illumination uniformity of the position-sensitive detector (PSD) in a sensing optical system, an optimization method is introduced in this paper. The ratio of the oblique ray section to the paraxial ray section is adjusted by circular and annular obscurations with different parameters; thus, the relative illumination on the image plane can be optimized. In our case, the size and position of the circular and annular obscurations are optimization variables. The result shows illumination uniformity on a PSD is enhanced from the original 12%-69.7%, and the precision is greatly improved. The method in this paper is proved to be effective and low cost and to have potential in many other applications.

The Effect of Structural Parameters on Seismic Behavior of Concrete-Filled Steel Tubular Frames with Buckling-Restrained Brace

In order to study the parameters influence on seismic behavior of concrete filled steel tubular (CFST) frame with bucking-restrained brace (BRB), the finite element analysis for CFST frame with BRB is studied in this paper, which is performed under low cyclic loading using the software of ABAQUS. Failure model and skeleton curve are comparative analyzed with the related experiment components, verifying that the finite element simulation of the CFST frame with BRB is effective. By changing the axial compression ratio of the column(n) and the steel ratio(α) of the column section respectively, the effect of the structural parameters on the seismic behavior of the CFST frames with BRB had been studied. The results shows that: with the increase of steel ratio of the column section, the lateral ultimate strength and the initial stiffness of the frame get higher, the lateral load(P) versus lateral displacement (Δ) hysteresis curves of the frame get plumper, and the energy dissipation of BRB remain basically unchanged; With the increase of axial compression ratio of the column, the lateral ultimate strength and the hysteretic behavior of the frame become low, whilst the energy dissipated by the BRB get higher.

Study on Capacity of High-Strength Angle Struts Connected by Single Limb

Experiment on bearing capacity of 24 Q460 high strength angle steel for compression members attached by one leg shows: the ultimate bearing capacity of the experiment value are higher than the calculated of the “Design of Latticed Steel Transmission Structures” (ASCE10-1997), on the same section in different slenderness ratio of components, the larger slenderness ratio, the higher the ratio; while on the same slenderness ratio in different sections, the greater width-thickness radio, the greater the ratio. Based on this problem, analyzing the current standard, a set of formulas based on high-strength angle struts connected by single Limb was brought, which can used for the design of the Q460 high-strength angle.

Experimental determination of the ratio of partial photoionization cross sections from Na 3p 2P3/2 by polarization anisotropy quantum beats

We demonstrate that polarization anisotropy quantum beats (QB) in two-photon ionization can be used to measure the ratio of photoionization cross sections to different angular momentum states of the photoelectron. Measurement of the ratio of photoionization cross sections has so far remained a non-trivial task by conventional photoionization techniques, including photoelectron angular distribution analysis. In this work, the amplitude of the polarization anisotropy QB for photoionization from the Na 3p 2P3/2 state was used to determine the ratio of the ionization cross sections near the ionization threshold. The experimental results are compared with theoretical predictions based on the quantum defect theory.

Investigating Influencing Factors on the Ductility Capacity of a Fixed-Head Reinforced Concrete Pile in Homogeneous Clay

AbstractThis study performs parametric analyses on the displacement ductility capacity of a fixed-head reinforced concrete pile in homogeneous clay, considering the spread of plasticity in the pile. The parametric study regards the pile as a limited ductility structure, which conditionally allows the pile to have inelastic response during large loading. The variables considered include the pile section parameters andp-ymodel parameters. A large number of pushover analyses are conducted to examine the displacement ductility capacity of the pile. The results show that the plastic hinging will occur at the pile head region for a fixed-head pile, and the displacement ductility capacity of the pile is mainly influenced by the over-strength ratio of the pile section. Furthermore, the second plastic region may occur in ground when the axial force is in high tension. Based on the design concept of limited ductility structures, the high tensile force in pile should be avoided in pile design. A quantitative relationship between the displacement ductility capacity and over-strength ratio is suggested for engineering applications.

Comparison of Lift and Drag Forces for Some Conical Bodies in Supersonic Flow Using Perturbation Techniques

Numerical methods are not always convergent especially in higher velocities when shock waves are involved. A comparison analysis is performed to study the supersonic flow over conical bodies of three different cross sections circular, elliptic and squircle (square with rounded corners) shaped using Perturbation techniques to find flow variables analytically. In order to find lift and drag forces the pressure force on the body is found, the component along x is drag and the component along z is lift. Three equations are obtained for lift to drag ratio of each cross section. The graphs for L/D show that for a particular cross section an increase in angle of attack, increases L/D. Comparing L/D in the three mentioned cross sections depicted that L/D is the greatest in squircle then in ellipse and the least in circle. The results are efficient in design of flying objects.

Numerical Analysis on the Temperature Distribution of Steel Tube Reinforced Concrete Columns Subjected to 3-Side Heating

The temperature fields of steel tube filled concrete columns are analyzed by a nonlinear FEM model in the paper. The theoretical results are validated by relative test results, and a good agreement is obtained. Using the theoretical models, the influencing laws of temperature rising time; section perimeter; steel reinforcement ratio and sectional core area ratio on temperature field of STRC subjected to 3-side fire are further discussed. By above parametric analysis, it has been found that the effects of heating time, sectional dimension and sectional core area ratio on temperature field are significant, but steel ratio has very little effect on temperature both of steel tube and of section surface.

Study on Accumulated Ductility Coefficient of Concrete Filled Steel Tubular Columns Based on Experimental Results

The hysteretic behaviors of concrete filled steel tube columns under low cyclic loads were analyzed for verification the accumulated energy dissipation performance. The accumulated ductility coefficient influencing factors, such as slenderness ratio, axial compression ratio and sectional steel ratio, were analyzed. It is indicated that these columns have a better energy dissipation capacity. The energy dissipation capacity decreases with the axial compression ratio increasing, but the influence of slenderness ratio and steel ratio to accumulated ductility coefficient is not clear, this is because the influence of difference loading system.

An improved method for generating formalin-fixed, paraffin-embedded cell blocks

Cell block preparations of body cavity effusions and washes are more reliable and reproducible than smears, cytospins, and ThinPrep. However, the routine preparation of cell blocks requires a large number of cells within a sample in order to obtain optimal paraffin blocks that contain a sufficient number of embedded cells. The achievement ratio of paraffin-embedded cell block sections from effusion samples has been shown to be 47·7%, which is not optimal for analysis. Therefore, we have developed an improved method called the twice paraffin embedding technique. We modified the current cell block preparation method for effusion samples by adding a ‘cylinder’ to obtain more cell pellets. One hundred and seven effusion and wash fluids samples, which were prospectively obtained from patients, were embedded using this new method. In our study, 82·2% (88/107) of the specimens were successfully embedded into paraffin cell block sections using the twice paraffin embedding technique. The twice paraffin embedding technique is a new, simple, and reliable cell block preparation technique that is suitable for different types of cytology specimens and requires less sample material. We hypothesize that this technique will be widely applicable in the field of cytopathology.

Temperature Field Calculation and Analysis within Steel Tube Reinforced Columns

The temperature field analysis method of steel tube reinforced columns under fire by finite element analysis software ABAQUS is proposed in this paper. The theoretical method is validated by tests, and the calculated results agree well with those of tests. On the basis of that, the influencing laws of temperature rising time; section perimeter; steel reinforcement ratio and sectional core area ratio on temperature field are discussed. It has been found that the surface temperatures of steel tube reinforced columns increase obviously with temperature rising time, and the temperatures of steel tubes and core concrete increase slowly. The effects of section size and sectional core area ratio on temperature field are significant, but steel ratio has very little effect on temperature both of steel tube and of sectional center. These achievements make it possible to study further theoretical study on the mechanic performance of steel tube reinforced concrete columns in fire.

J/ψ and ψ(2S) production in pp collisions at s√=7Tev

A measurement of the J/ψ and ψ(2S) production cross sections in pp collisions at √s = 7TeV with the CMS experiment at the LHC is presented. The data sample corresponds to an integrated luminosity of 37 pb^(−1). Using a fit to the invariant mass and decay length distributions, production cross sections have been measured separately for prompt and non-prompt charmonium states, as a function of the meson transverse momentum in several rapidity ranges and integrated in the kinematical regions considered in this study. In addition, cross sections restricted to the acceptance of the CMS detector are given, which are not affected by the polarization of the charmonium states. The ratio of the differential production cross sections of the two states, where systematic uncertainties largely cancel, is also determined. The branching fraction of the inclusive B → ψ(2S)X decay is extracted from the ratio of the non-prompt cross sections to be: B(B → ψ(2S)X) = (3.08±0.12(stat+syst.)±0.13(theor.)±0.42(B_(PDG)10^(−3)

Total hadronic cross section and the elastic slope: An almost model-independent connection

An almost model-independent parametrization for the ratio of the total cross section to the elastic slope, as function of the center of mass energy, is introduced. The analytical result is based on the approximate relation of this quantity with the ratio R of the elastic to total cross section and empirical fits to the R data from proton–proton scattering above 10 GeV, under the conditions of asymptotic unitarity and the black-disk limit. This parametrization may be useful in studies of extensive air showers and the determination of the proton–proton total cross section from proton–air production cross section in cosmic-ray experiments.

Exclusive Central Meson Production in Proton Antiproton Collisions at the Tevatron

It has been known since the days of the Intersecting Storage Rings, ISR, at CERN, that one can have pp interactions with more than one pomeron, ℙ, exchanged, known as double pomeron exchange. Exclusive hadronic systems, produced by double pomeron exchange, DℙE, have the potential of opening a rich new window on hadron spectroscopy and the diffraction mechanism. We have studied events of the type p + → p + X + where X is a hadron pair (mostly π + π − ) at √s = 900 GeV and 1960 GeV in the Collider Detector at Fermilab (CDF). The hadron pair is central, y ≈ 0, and between two rapidity gaps Δy ≈ 4. The dominant process is double pomeron exchange, DℙE, with restrictions on the quantum numbers of X: Q = S = 0, C = +1, J = 0 or 2. The mass spectra, with about 300K candidate events assumed to be π + π − , shows strong resonant structures attributed to f 0 and f 2 states. We give the ratio of cross sections at √s = 900 GeV and 1960 GeV, and compare with Regge expectations.

Numerical Study on Concrete Filled GFRP-Steel Tube under Cyclic Loading

For the purpose of investigating the strengthening effectiveness of GFRP on concrete filled steel tube structure under combined seismic loading and comparing with CFRP ones, numerical simulations of quasi-static test are developed by using ABAQUS. The establishment of finite element model is tested to be feasible by comparing the numerical load-displacement hysteretic curves and their skeleton curves with the experimental ones. Further studies are carried out through changing models’ FRP (GFRP/CFRP) thickness, axial compression ratio and cross sectional steel ratio. Simulation results show that specimens with thicker FRP (GFRP/CFRP) equip better energy dissipation capacity and higher bearing capacity. In elastic-plastic stage the stiffness of specimen degradation becomes more serious as axial compression increases. Energy dissipation capacity is enhanced as cross sectional steel ratio increases.

Bridging Toughening and Fracture Energy of X-Type Fiber Reinforced Cementitious Composites

Based on the fiber bridging model and constant frictional interface stress, this paper derived the P-δ relation for the X-type fiber pulled out of cementitious matrix. By considering the random distributions of the bridging fibers and supposing that rupture of fiber never occurs, it derived the σB-δ relation of a single macro-crack, from which the fracture energy equation was deduced by integral. The derived toughening equations have continuous and explicit forms and are convenient for the approximate estimate of the fracture toughness of the composite. The fracture energy expression suggests that increasing fiber volume fraction, utilizing longer fibers or slender fibers and improving interface bonding are effective methods for improving the composite fracture toughness, while adopting fibers with higher elastic modulus is not a preferred suggestion. It is also found that when using X-type fibers to replace cylindrical fibers with same section area, one can obtain 3~8 times of fracture energy (corresponding leg length-width ratio of the X-type fiber cross section is 5~50).

Intermediate Diaphragms Arrangement in Horizontal Curved Composite Box-Girder Bridge with Corrugated Webs

Horizontally curved box girder bridges inherently exhibit complex torsional and distortional behavior as well as bending due to the initial curvature. As to the horizontal curved composite box-girder bridges with corrugated webs, diaphragms were arranged reasonably to reduce torsional and distortion effect for safety and stability due to the coupling of bending and torsion effect for initial curvature and reduced bending stiffness in horizontal direction for corrugated steel webs. Finite element models for a 3-spans continuous horizontal curved composite box girder bridges with corrugated webs were established. Comparing the ratio of warping normal stress to bending normal stress, the influence of the number and spacing for diaphragms on distortion control for curved bridges is investigated. Extensive parametric studies (including central angle, the aspect ratio of the box section, the spacing of the intermediate diaphragms)are performed and the design suggestions for the maximum spacing of the intermediate diaphragms are presented.

Design of shrinkage microvalve in microchannel with hydrophilic and hydrophobic walls

This paper presents a simple design of shrinkage microvalves which can be used to effectively stopping capillary flow inside a microchannel with hydrophilic and hydrophobic walls. Based on the relationship between capillary pressure and cross-section geometry of a microchannel, the microvalve is designed with a critical ratio of rectangular section. In order to verify the feasibility of the design rule, a couple of shrinkage microvalves with different aspect ratios of cross-section are fabricated by using PDMS bonded with glass wafer. The experiment demonstrates the stopping effect of the proposed design of shrinkage microvalve.

Synthesis and photophysical properties of novel two-photon absorption chromophores and research on its solid-state device

Three novel distyrylbenzene derivatives have been synthesized and their optical properties have been investigated. All the compounds give large two-photon absorption (TPA) cross sections and their TPA cross sections are significantly enhanced with the temperature decreases. Especially, the compound of TMVDB is highly luminescent as the fluorescence quantum yield of 0.83. TPA cross section of TMVDB is 1164 GM and ratio of TPA cross section divided to molecular weight is as high as 2.08. All the results of TMVDB show its excellent TPA induced emission performance. The TMVDB is doped into the solid matrix and a solid-state film with strong TPA induced emission is obtained.

일정체적 원호형 곡선보의 자유진동

This paper deals with free vibrations of the circular curved beams with constant volume, whose cross sectional shapes are the circular solid cross-sections. Volumes of the objective beam are always held in constant regardless shape functions of the cross-sectional radius. The shape functions are chosen as the linear, parabolic and sinusoidal ones. Ordinary differential equations governing free vibrations of such beam are derived and solved numerically for determining the natural frequencies. In numerical examples, the hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, relationships between frequency parameters and various beam parameters such as rise ratio, section ratio, elasticity ratio, volume ratio, slenderness ratio and taper type are reported in tables and figures.