One-step preparation of copper nanorods with rectangular cross sections

2006 ◽  
Vol 139 (8) ◽  
pp. 412-414 ◽  
Author(s):  
Xiaojun Zhang ◽  
Dongen Zhang ◽  
Xiaomin Ni ◽  
Huagui Zheng
Keyword(s):  
Cross Sections ◽  
One Step ◽  
Copper Nanorods

Heavy-ion reactions as spin probes

1987 ◽  
Vol 65 (6) ◽  
pp. 609-613 ◽  
Author(s):  
Sam M. Austin ◽  
N. Anantaraman ◽  
J. S. Winfield
Keyword(s):  
Cross Sections ◽  
Reaction Mechanisms ◽  
Heavy Ion ◽  
Spin Transfer ◽  
Calibration Function ◽  
Matrix Elements ◽  
Heavy Ion Reactions ◽  
One Step ◽  
The One ◽  
Gamow Teller

Heavy-ion reactions can be powerful probes for spin-transfer strength in nuclei, provided their reaction mechanism is simple so that a correlation can be established between cross sections and the relevant matrix elements. We discuss the desirable features of heavy-ion reactions in general and a series of tests of reaction mechanisms that have been carried out for two of the most favorable reactions; (6Li, 6He) and (12C, 12N). We establish that the (6Li, 6He) reaction is one-step in nature above 25 MeV∙nucleon−1 and establish a calibration function relating cross sections and Gamow–Teller matrix elements. We also find that the (12C, 12N) reaction is likely to be dominated by the one-step process above about 50 MeV∙nucleon−1.

Fabrication and Characterization of Porous Copper Nanorods with Rectangular Cross Sections

2006 ◽  
Vol 35 (10) ◽  
pp. 1142-1143 ◽  
Author(s):  
Xiaojun Zhang ◽  
Dongen Zhang ◽  
Xiaomin Ni ◽  
Huagui Zheng
Keyword(s):  
Cross Sections ◽  
Porous Copper ◽  
Fabrication And Characterization ◽  
Copper Nanorods

Numerical Analysis of a Rigid Node of a Spatial Timber Frame Made of Structural Elements with Built-up Cross-Sections

2013 ◽  
Vol 778 ◽  
pp. 639-646 ◽  
Author(s):  
Cristina E. Lanivschi ◽  
Alexandru Secu ◽  
Gabriela M. Atanasiu
Keyword(s):  
Numerical Analysis ◽  
Finite Elements ◽  
Elastic Properties ◽  
Design Process ◽  
Cross Sections ◽  
Structural Elements ◽  
Cross Sectional ◽  
Timber Frame ◽  
One Step ◽  
Internal Forces

Considering wood currently used in construction domain, it may be observed that it possesses good strengths, but reduced modules of elasticity. This drawback may be prevented by creating structures with rigid nodes or by using hybrid or composed cross-sections for the structural elements.The paper consists of numerical analysis of a timber frame with rigid nodes, assuming composed cross-sections for the structural elements, made of four props with cross-sectional dimensions of 0.1x0.1 m each - for columns and two chords of 0.1x0.1 m each - for beams.Analyzing this type of structures by considering equivalent cross sections` properties of the structural elements, the real phenomena may not be covered, since it doesn`t consider all elastic characteristics of wood, resulting in different stress` distribution in the structural elements.The analyze of this structure considering both real solid cross-sections and all elastic properties of wood by using specialized software, leads to a laborious work because of the high number of finite elements. Thereby, a two-step analysis is proposed: the first one consists in solving the spatial timber frame with bar type finite elements and the elastic properties parallel to the grain, as provided by design codes. In the second step, an intermediary node is detached and loaded with the internal forces obtained from the first step, considering all elastic parameters of wood and using solid type finite elements.Currently, in the design process, only the first step in performed. The two-step analysis aims to compare the results with those obtained using the strength of materials methods, relieving the necessary corrections in the case of one-step design process.

scholarly journals Microscopic coupled-channel calculation of proton and alpha inelastic scattering to the 41+ and 42+ states of 24Mg

2021 ◽  
Author(s):  
Yoshiko Kanada-En'yo ◽  
Kazuyuki Ogata
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Angular Distributions ◽  
Channel Calculation ◽  
Triaxial Deformation ◽  
Step Process ◽  
Coupled Channel Calculation ◽  
One Step ◽  
Coupled Channel ◽  
Α Particles

Abstract The triaxial and hexadecapole deformations of the Kπ = 0+ and Kπ = 2+ bands of 24Mg have been investigated by the inelastic scatterings of various probes, including electrons, protons, and alpha(α) particles, for a prolonged time. However, it has been challenging to explain the unique properties of the scatterings observed for the 41+ state through reaction calculations. This paper investigates the structure and transition properties of the Kπ = 0+ and Kπ = 2+ bands of 24Mg employing the microscopic structure and reaction calculations via inelastic proton and α scattering. In particular, the E4 transitions to the 41+ and 42+ states are reexamined. The structure of 24Mg was calculated employing the variation after the parity and total angular momentum projections in the framework of the antisymmetrized molecular dynamics (AMD). The inelastic proton and α reactions were calculated by the microscopic coupled-channel (MCC) approach by folding the Melbourne g-matrix NN interaction with the AMD densities of 24Mg. Reasonable results were obtained on the properties of the structure, including the energy spectra and E2 and E4 transitions of the Kπ = 0+ and Kπ = 2+ bands owing to the enhanced collectivity of triaxial deformation. The MCC+AMD calculation successfully reproduced the angular distributions of the 41+ and 42+ cross sections of proton scattering at incident energies of Ep = 40–100MeV and α scattering at Eα = 100–400 MeV. This is the first microscopic calculation to describe the unique properties of the 01+ → 41+ transition. In the inelastic scattering to the 41+ state, the dominant two-step process of the 01+→ 21+→ 41+ transitions and the deconstructive interference in the weak one-step process were essential.

INCLUSIVE (3He, t) REACTION IN DELTA EXCITATION REGION

1995 ◽  
Vol 04 (01) ◽  
pp. 181-191 ◽  
Author(s):  
NEELIMA G. KELKAR ◽  
B.K. JAIN
Keyword(s):  
Experimental Data ◽  
Angular Distribution ◽  
Cross Sections ◽  
Eikonal Approximation ◽  
Fermi Gas ◽  
Distorted Wave ◽  
Excitation Region ◽  
One Step ◽  
The One ◽  
Nuclear Response

Using the one step reaction mechanism, calculations are presented for the overall features of the inclusive (3 He , t) reaction on various target nuclei in the delta excitation region. The interaction for the elementary pp→nΔ++ process is given by one-pion-exchange, and is written in the covariant relativistic form. The values of the parameters in the interaction are chosen such that the interaction successfully describes the spin averaged experimental elementary cross-sections. The distortion in the entrance and exit channels is described in the eikonal approximation, and the nuclear response is described in the “distorted wave Fermi gas model”. The cross-sections for the triton energy spectrum, angular distribution, and the total events at 0° on several nuclei, are calculated and compared with the corresponding experimental data. The main features of the measured cross-sections are reproduced.

Multipole decomposition of Gamow–Teller strength

1987 ◽  
Vol 65 (6) ◽  
pp. 660-665 ◽  
Author(s):  
Murray A. Moinester
Keyword(s):  
Charge Exchange ◽  
Cross Sections ◽  
Present Report ◽  
Random Phase ◽  
Impulse Approximation ◽  
General Importance ◽  
Least Squares Fit ◽  
Distorted Wave Impulse Approximation ◽  
One Step ◽  
Gamow Teller

Doubly differential continuum cross sections from the 90Zr(p, n)90Nb reaction have been analyzed via a multipoledecomposition technique. No quasi-free charge-exchange background has been subtracted, following the assumption that the observed cross sections are primarily due to one-step charge-exchange leading to 1p–1h states of all multipolarities to all excitations. The theoretical shapes of the differential cross sections for each Jπ multipole have been taken from random-phase approximation (RPA)–distorted-wave impulse approximation (DWIA) calculations. The experimental dσ/dΩ, for each 1 MeV excitation-energy bin have been decomposed into different multipole components by a least squares fit. This RPA-based analysis should determine the Jπ = 1+ cross sections with different, and also fewer, assumptions than usual for describing the underlying background. It can be of general importance in determining the extent of possible quenching of Gamow–Teller (GT) strength. The present decomposition accounts for all the theoretically predicted GT strength. The purpose of the present report is to illustrate an analysis based on RPA–DWIA shapes rather than to present final-decomposition results.

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

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