Roaming Reactions and Dynamics in the van der Waals Region

2020 ◽  
Vol 71 (1) ◽  
pp. 77-100 ◽  
Author(s):  
Arthur G. Suits
Keyword(s):  
Long Range ◽  
Internal State ◽  
Chemical Reactivity ◽  
Van Der Waals ◽  
Quantum Effects ◽  
Experimental Results ◽  
Unexpected Formation ◽  
Chemical Systems ◽  
Definition Of

Roaming reactions were first clearly identified in photodissociation of formaldehyde 15 years ago, and roaming dynamics are now recognized as a universal aspect of chemical reactivity. These reactions typically involve frustrated near-dissociation of a quasibound system to radical fragments, followed by reorientation at long range and intramolecular abstraction. The consequences can be unexpected formation of molecular products, depletion of the radical pool in chemical systems, and formation of products with unusual internal state distributions. In this review, I examine some current aspects of roaming reactions with an emphasis on experimental results, focusing on possible quantum effects in roaming and roaming dynamics in bimolecular systems. These considerations lead to a more inclusive definition of roaming reactions as those for which key dynamics take place at long range.

scholarly journals Tuning adlayer-substrate interactions of graphene/h-BN heterostructures on Cu(111)–Ni and Ni(111)–Cu surface alloys

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1916-1927
Author(s):  
Jianmei Huang ◽  
Qiang Wang ◽  
Pengfei Liu ◽  
Guang-hui Chen ◽  
Yanhui Yang
Keyword(s):  
Long Range ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Alloy Surface ◽  
Surface Alloys ◽  
Substrate Interactions

The evolution of the interface and interaction of h-BN and graphene/h-BN (Gr/h-BN) on Cu(111)–Ni and Ni(111)–Cu surface alloys versus the Ni/Cu atomic percentage on the alloy surface were comparatively studied by DFT-D2, including critical long-range van der Waals forces.

Definition of the yield point in plasticity and its effect on the shape of the yield locus

1966 ◽  
Vol 1 (4) ◽  
pp. 331-338 ◽  
Author(s):  
T C Hsu
Keyword(s):  
Yield Point ◽  
Experimental Work ◽  
Strain Curve ◽  
Yield Locus ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Proportional Limit ◽  
Stress Strain ◽  
Small Section ◽  
Definition Of

Three different definitions of the yield point have been used in experimental work on the yield locus: proportional limit, proof strain and the ‘yield point’ by backward extrapolation. The theoretical implications of the ‘yield point’ by backward extrapolation are examined in an analysis of the loading and re-loading stress paths. It is shown, in connection with experimental results by Miastkowski and Szczepinski, that the proportional limit found by inspection is in fact a point located by backward extrapolation based on a small section of the stress-strain curve, near the elastic portion of the curve. The effect of different definitions of the yield point on the shape of the yield locus and some considerations for the choice between them are discussed.

LONG RANGE FORCES BETWEEN HYDROGEN MOLECULES

1955 ◽  
Vol 33 (11) ◽  
pp. 668-678 ◽  
Author(s):  
F. R. Britton ◽  
D. T. W. Bean
Keyword(s):  
Wave Function ◽  
Long Range ◽  
Ground State ◽  
Close Agreement ◽  
Van Der Waals ◽  
Wave Functions ◽  
Numerical Factor ◽  
Hydrogen Molecules ◽  
Static Quadrupole

Long range forces between two hydrogen molecules are calculated by using methods developed by Massey and Buckingham. Several terms omitted by them and a corrected numerical factor greatly change results for the van der Waals energy but do not affect their results for the static quadrupole–quadrupole energy. By using seven approximate ground state H2 wave functions information is obtained regarding the dependence of the van der Waals energy on the choice of wave function. The value of this energy averaged over all orientations of the molecular axes is found to be approximately −11.0 R−6 atomic units, a result in close agreement with semiempirical values.

Oxygen Enrichment in Combustion Processes: Comparative Experimental Results From Several Application Fields

1991 ◽  
Vol 113 (2) ◽  
pp. 122-126
Author(s):  
M. De Lucia
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Copper Alloys ◽  
Ceramic Materials ◽  
Oxygen Enrichment ◽  
Experimental Results ◽  
Ferrous Metals ◽  
Definition Of ◽  
Application Fields ◽  
Combustion Processes

The effects of using oxygen to partially or wholly replace fuel air in small-size melting furnaces were studied over a range of application fields. Following definition of the useful parameters, testing was conducted on furnaces for melting glass, ferrous metals (pigiron), nonferrous metals (copper alloys), and ceramic materials. In all cases, oxygen-enrichment was found to provide significant energy savings, as well as notable advantages in terms of both plant output and energy consumption.

IMPROVING THE ACTIVITIES OF INTERNAL STATE AUDIT BODIES IN THE CONTEXT OF DIGITALIZATION

2020 ◽  
Vol 3 (12) ◽  
pp. 118-124
Author(s):  
M. A. ABUGALIYEVA ◽  
◽  
B. A. ALIBEKOVA ◽  
Keyword(s):  
Audit Committee ◽  
Internal State ◽  
State Audit ◽  
Ministry Of Finance ◽  
The Republic ◽  
Definition Of

The article deals with the activities of the authorized body for internal state audit in the Republic of Kazakhstan. The author's definition of internal state audit is given. The analysis of the activities of the Internal State Audit Committee of the Ministry of Finance of the Republic of Kazakhstan was carried out and problematic aspects were identified. Reasonable suggestions have been made to resolve the problems.

Computer Simulation of Colloidal Aggregation Induced by Directionalism of Long Range van der Waals Forces

2007 ◽  
Vol 23 (08) ◽  
pp. 1241-1246 ◽  
Author(s):  
XIONG Hai-Ling ◽  
◽  
◽  
YUAN Yong-Zhi ◽  
LI Hang ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Long Range ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Colloidal Aggregation

Looking for Patterns

2021 ◽  
pp. 57-73
Author(s):  
Talia Dan-Cohen
Keyword(s):  
Life Forms ◽  
Experimental Results ◽  
Close Attention ◽  
Vast Array ◽  
Observational Skills ◽  
Definition Of ◽  
By Products

This chapter focuses on ambiguous experimental results, paying close attention to experimental processes and tracking the ways that practitioners tackle, reason, and think through puzzling experimental results. It investigates the context of experiments with modified life-forms and experimental results that take the form of a vast array of biotic not-quites. It also highlights organismic by-products that point in various directions when it comes to figuring out how much control synthetic biologists have over their designs and what steps should be taken as correctives. The chapter explains how experiments often come packaged together with the choices, standards, and observational skills of others. It discusses the problem of the definition of growth that was deferred through the delineation of a category for the indeterminate results.

scholarly journals The total occlusal convergence of the abutment of a partial fixed dental prosthesis: A definition and a clinical technique for its assessment

2013 ◽  
Vol 07 (04) ◽  
pp. 509-513 ◽  
Author(s):  
John S. Mamoun
Keyword(s):  
Dental Prosthesis ◽  
Experimental Results ◽  
High Magnification ◽  
Operating Microscope ◽  
Alternative Definition ◽  
Fixed Dental Prosthesis ◽  
Definition Of ◽  
The Ideal

ABSTRACTThe abutment(s) of a partial fixed dental prosthesis (PFDP) should have a minimal total occlusal convergence (TOC), also called a taper, in order to ensure adequate retention of a PFDP that will be made for the abutment(s), given the height of the abutment(s). This article reviews the concept of PFDP abutment TOC and presents an alternative definition of what TOC is, defining it as the extent to which the shape of an abutment differs from an ideal cylinder shape of an abutment. This article also reviews experimental results concerning what is the ideal TOC in degrees and explores clinical techniques of estimating the TOC of a crown abutment. The author suggests that Dentists use high magnification loupes (×6-8 magnification or greater) or a surgical operating microscope when preparing crown abutments, to facilitate creating a minimum abutment TOC.

Sign in / Sign up

Export Citation Format

Share Document