Interference Effects in Two-Step Reaction Processes

1972 ◽  
Vol 50 (7) ◽  
pp. 700-702 ◽  
Author(s):  
D. G. Burke ◽  
J. C. Waddington
Keyword(s):  
Simple Expression ◽  
Single Step ◽  
Excitation Mechanism ◽  
Interference Effects ◽  
Reaction Paths ◽  
Reaction Processes ◽  
Insight Into

In reaction studies on even–even target nuclei, one is frequently interested in a state for which (a) the population by single-step processes is forbidden, (b) the dominant excitation mechanism is by two-step processes, and (c) two competing reaction paths are involved. A simple expression is given for such cases which offers some insight into the effects of interference between these two paths. A comparison of the predictions of this expression with several types of experiment is presented. In particular, an interpretation is presented for some recent (3He, α) reaction results which could not previously be explained.

Note on Interference Effects in Two-Step Reaction Processes

1975 ◽  
Vol 53 (23) ◽  
pp. 2590-2592
Author(s):  
J. Cejpek ◽  
J. Dobeš
Keyword(s):  
Perturbation Theory ◽  
Point Of View ◽  
Order Perturbation ◽  
Interference Effects ◽  
Qualitative Explanation ◽  
First Order ◽  
One Step ◽  
Step Transition ◽  
Reaction Processes ◽  
First Order Perturbation

The reaction processes in which a one-step transition is forbidden are analyzed from the point of view of the first order perturbation theory. The interference between two competing two-step reaction paths is found to be always constructive. A qualitative explanation of the experimentally observed reaction intensities is presented.

Single-step hydrothermal synthesis of nitrogen-doped ZnO nanostructures and an insight into its electrochemical properties

2021 ◽  
Author(s):  
Alisha Mary Manoj ◽  
Leema Rose Viannie ◽  
Chittur Krishnaswamy Subramaniam ◽  
Narayanasamy Arunai Nambi Raj ◽  
Geetha Manivasagam
Keyword(s):  
Hydrothermal Synthesis ◽  
Electrochemical Properties ◽  
Single Step ◽  
Zno Nanostructures ◽  
Nitrogen Doped ◽  
Doped Zno ◽  
Insight Into

A geometrical derivation of the shape density

1991 ◽  
Vol 23 (03) ◽  
pp. 496-514 ◽  
Author(s):  
Colin R. Goodall ◽  
Kanti V. Mardia
Keyword(s):  
Rotation Group ◽  
Shape Space ◽  
Canonical System ◽  
Single Step ◽  
Equivalence Classes ◽  
Polar Coordinates ◽  
Dimension 2 ◽  
Original Derivation ◽  
Insight Into ◽  
Original Configuration

The density for the shapes of random configurations of N independent Gaussian-distributed landmarks in the plane with unequal means was first derived by Mardia and Dryden (1989a). Kendall (1984), (1989) describes a hierarchy of spaces for landmarks, including Euclidean figure space containing the original configuration, preform space (with location removed), preshape space (with location and scale removed), and shape space. We derive the joint density of the landmark points in each of these intermediate spaces, culminating in confirmation of the Mardia–Dryden result in shape space. This three-step derivation is an appealing alternative to the single-step original derivation, and also provides strong geometrical motivation and insight into Kendall's hierarchy. Preform space and preshape space are respectively Euclidean space with dimension 2(N–1) and the sphere in that space, and thus the first two steps are reasonably familiar. The third step, from preshape space to shape space, is more interesting. The quotient by the rotation group partitions the preshape sphere into equivalence classes of preshapes with the same shape. We introduce a canonical system of preshape coordinates that include 2(N–2) polar coordinates for shape and one coordinate for rotation. Integration over the rotation coordinate gives the Mardia–Dryden result. However, the usual geometrical intuition fails because the set of preshapes keeping the rotation coordinate (however chosen) fixed is not an integrable manifold. We characterize the geometry of the quotient operation through the relationships between distances in preshape space and distances among the corresponding shapes.

A geometrical derivation of the shape density

1991 ◽  
Vol 23 (3) ◽  
pp. 496-514 ◽  
Author(s):  
Colin R. Goodall ◽  
Kanti V. Mardia
Keyword(s):  
Rotation Group ◽  
Shape Space ◽  
Canonical System ◽  
Single Step ◽  
Equivalence Classes ◽  
Polar Coordinates ◽  
Dimension 2 ◽  
Original Derivation ◽  
Insight Into ◽  
Original Configuration

The density for the shapes of random configurations of N independent Gaussian-distributed landmarks in the plane with unequal means was first derived by Mardia and Dryden (1989a). Kendall (1984), (1989) describes a hierarchy of spaces for landmarks, including Euclidean figure space containing the original configuration, preform space (with location removed), preshape space (with location and scale removed), and shape space. We derive the joint density of the landmark points in each of these intermediate spaces, culminating in confirmation of the Mardia–Dryden result in shape space. This three-step derivation is an appealing alternative to the single-step original derivation, and also provides strong geometrical motivation and insight into Kendall's hierarchy. Preform space and preshape space are respectively Euclidean space with dimension 2(N–1) and the sphere in that space, and thus the first two steps are reasonably familiar. The third step, from preshape space to shape space, is more interesting. The quotient by the rotation group partitions the preshape sphere into equivalence classes of preshapes with the same shape. We introduce a canonical system of preshape coordinates that include 2(N–2) polar coordinates for shape and one coordinate for rotation. Integration over the rotation coordinate gives the Mardia–Dryden result. However, the usual geometrical intuition fails because the set of preshapes keeping the rotation coordinate (however chosen) fixed is not an integrable manifold. We characterize the geometry of the quotient operation through the relationships between distances in preshape space and distances among the corresponding shapes.

scholarly journals Supercapacitors based on graphene/pseudocapacitive materials

2017 ◽  
Vol 82 (4) ◽  
pp. 411-416
Author(s):  
Denis Sacer ◽  
Magdalena Kralj ◽  
Suzana Sopcic ◽  
Milica Kosevic ◽  
Aleksandar Dekanski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Precursor Solution ◽  
Single Step ◽  
X Ray ◽  
Supercapacitor Application ◽  
Microwave Assisted ◽  
Simultaneous Synthesis ◽  
Insight Into ◽  
Scanning Electron

Composites of graphene and SnO2 were successfully prepared by a single step simultaneous synthesis of SnO2 and reduction of graphene oxide (GO). Three different compositions of precursor solution resulted in different composite materials containing graphene and SnO2. The reaction was realized by microwave-assisted hydrothermal synthesis. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) gave insight into the morphology and composition of the obtained materials. Good capacitive/pseudocapacitive properties of the obtained material suitable for supercapacitor application were registered by cyclic voltammetry, from where specific capacitance values up to 93 F g-1 were determined.

scholarly journals Microscopic insight into the single step growth of in-plane heterostructures between graphene and hexagonal boron nitride

Nano Research ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 675-682 ◽  
Author(s):  
Thanh Hai Nguyen ◽  
Daniele Perilli ◽  
Mattia Cattelan ◽  
Hongsheng Liu ◽  
Francesco Sedona ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Single Step ◽  
Step Growth ◽  
Insight Into

scholarly journals Mechanistic insight into the formation of colloidal WS2 nanoflakes in hot alkylamine media

2019 ◽  
Vol 1 (7) ◽  
pp. 2772-2782 ◽  
Author(s):  
Riccardo Scarfiello ◽  
Andrea Cesari ◽  
Davide Altamura ◽  
Sofia Masi ◽  
Concetta Nobile ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
Chemical Nature ◽  
Single Step ◽  
Lateral Size ◽  
Mechanistic Insight ◽  
Key Points ◽  
Insight Into ◽  
Long Chain

Non-hydrolytic synthesis assisted by long-chain amphiphilic surfactant is exploited to generate dimension-controllable 2D-WS2 nanoflakes in a single-step protocol, where the chemical nature and steric hindrance of the alkylamine are the key points to modulate the lateral size finally achieved.

The half-widths of Bragg intensity profiles measured with a triple-crystal diffractometer at a synchrotron-radiation source. I. Derivation of a simple expression for the full width at half-maximum

1993 ◽  
Vol 26 (6) ◽  
pp. 753-755 ◽  
Author(s):  
E. Rossmanith
Keyword(s):  
Synchrotron Radiation ◽  
Radiation Source ◽  
Block Size ◽  
Simple Expression ◽  
Synchrotron Radiation Source ◽  
Full Width ◽  
Acta Cryst ◽  
Mosaic Block ◽  
New Formula ◽  
Insight Into

On the basis of the expressions given by Rossmanith [Acta Cryst. (1992), A48, 596–610; (1993), A49, 80–91], a simple approximation is derived for the half-widths of Bragg intensity profiles measured with a triple-crystal diffractometer at a synchrotron-radiation source. This new formula facilitates insight into the effects of four parameters – divergence, wavelength spread, mosaic spread and mosaic block size – on the widths of the profiles.

scholarly journals Prevalence and determinants of intravenous admixture preparation errors: A prospective observational study in a university hospital

2021 ◽  
Author(s):  
Janique G. Jessurun ◽  
Nicole G. M. Hunfeld ◽  
Joost van Rosmalen ◽  
Monique van Dijk ◽  
Patricia M. L. A. van den Bemt
Keyword(s):  
Observational Study ◽  
Prospective Observational Study ◽  
Time Window ◽  
Single Step ◽  
University Hospital ◽  
Preparation Technique ◽  
Patient Harm ◽  
Preparation Errors ◽  
Infusion Fluid ◽  
Insight Into

AbstractBackground Intravenous admixture preparation errors (IAPEs) may lead to patient harm. Insight into the prevalence as well as the determinants associated with these IAPEs is needed to elicit preventive measures. Aim The primary aim of this study was to assess the prevalence of IAPEs. Secondary aims were to identify the type, severity, and determinants of IAPEs. Method A prospective observational study was performed in a Dutch university hospital. IAPE data were collected by disguised observation. The primary outcome was the proportion of admixtures with one or more IAPEs. Descriptive statistics were used for the prevalence, type, and severity of IAPEs. Mixed-effects logistic regression analyses were used to estimate the determinants of IAPEs. Results A total of 533 IAPEs occurred in 367 of 614 admixtures (59.8%) prepared by nursing staff. The most prevalent errors were wrong preparation technique (n = 257) and wrong volume of infusion fluid (n = 107). Fifty-nine IAPEs (11.1%) were potentially harmful. The following variables were associated with IAPEs: multistep versus single-step preparations (adjusted odds ratio [ORadj] 4.08, 95% confidence interval [CI] 2.27–7.35); interruption versus no interruption (ORadj 2.32, CI 1.13–4.74); weekend versus weekdays (ORadj 2.12, CI 1.14–3.95); time window 2 p.m.-6 p.m. versus 7 a.m.-10 a.m. (ORadj 3.38, CI 1.60–7.15); and paediatric versus adult wards (ORadj 0.14, CI 0.06–0.37). Conclusion IAPEs, including harmful IAPEs, occurred frequently. The determinants associated with IAPEs point to factors associated with preparation complexity and working conditions. Strategies to reduce the occurrence of IAPEs and therefore patient harm should target the identified determinants.

The roles of buckled geometry and water environment in the excitonic properties of graphitic C3N4

Nanoscale ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 3738-3743 ◽  
Author(s):  
Jiuyu Sun ◽  
Xingxing Li ◽  
Jinlong Yang
Keyword(s):  
Water Environment ◽  
Excitation Mechanism ◽  
Excitonic Properties ◽  
Insight Into

An insight into the photo-excitation mechanism of 2D photocatalyst g-C3N4 in a water environment.

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