Low Energy Indicators of High Energy Processes

Microelectronic fabrication of Si typically involves high-temperature or high-energy processes. For instance, wafer fabrication, transistor fabrication, and silicidation are all above 500°C. Contrary to that tradition, we believe low-energy processes constitute a better alternative to enable the industrial application of single-molecule devices based on 2D materials. The present work addresses the postsynthesis processing of graphene at unconventional low temperature, low energy, and low pressure in the poly methyl-methacrylate- (PMMA-) assisted transfer of graphene to oxide wafer, in the electron-beam lithography with PMMA, and in the plasma patterning of graphene with a PMMA ribbon mask. During the exposure to the oxygen plasma, unprotected areas of graphene are converted to graphene oxide. The exposure time required to produce the ribbon patterns on graphene is 2 minutes. We produce graphene ribbon patterns with ∼50 nm width and integrate them into solid state and liquid gated transistor devices.

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Probing the unidentified Fermi blazar-like population using optical polarization and machine learning

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1008 ◽

2019 ◽

Vol 486 (3) ◽

pp. 3415-3422 ◽

Cited By ~ 2

Author(s):

I Liodakis ◽

D Blinov

Keyword(s):

Machine Learning ◽

Predictive Power ◽

High Energy ◽

Point Sources ◽

Low Energy ◽

Optical Polarization ◽

Sky Surveys ◽

Γ Ray ◽

Energy Processes ◽

The Universe

ABSTRACT The Fermi γ-ray space telescope has revolutionized our view of the γ-ray sky and the high-energy processes in the Universe. While the number of known γ-ray emitters has increased by orders of magnitude since the launch of Fermi, there is an ever increasing number of, now more than a thousand, detected point sources whose low-energy counterpart is to this day unknown. To address this problem, we combined optical polarization measurements from the RoboPol survey as well as other discriminants of blazars from publicly available all-sky surveys in machine learning (ML, random forest and logistic regression) frameworks that could be used to identify blazars in the Fermi unidentified fields with an accuracy of >95 per cent. Out of the potential observational biases considered, blazar variability seems to have the most significant effect reducing the predictive power of the frameworks to ${\sim }80\hbox{-}85{{\ \rm per\ cent}}$. We apply our ML framework to six unidentified Fermi fields observed using the RoboPol polarimeter. We identified the same candidate source proposed by Mandarakas et al. for 3FGL J0221.2 + 2518.

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Quantum electrodynamics. II

Mathematical Proceedings of the Cambridge Philosophical Society ◽

10.1017/s0305004100021186 ◽

1939 ◽

Vol 35 (3) ◽

pp. 438-462

Author(s):

F. Hoyle

Keyword(s):

Quantum Electrodynamics ◽

Finite Size ◽

Direct Calculation ◽

High Energy ◽

Low Energy ◽

Successive Approximations ◽

Method Of Successive Approximations ◽

Self Energy ◽

Energy Processes ◽

Real Test

It is shown in this paper and the preceding one that two separate forms of theory can be developed in which a “finite size” is attributed to a charged particle by means of its interaction with the radiation field. The region attributed in this way to the particle is four dimensional and is determined in such a manner that the usual difficulties with relativistic invariance do not arise.The advantage of such a theory becomes clear when the theory is applied to those problems in which the usual calculations give infinite results. The problem of the method of successive approximations is considered and satisfactory results are obtained provided that the space dimensions of the finite region are of the order of the classical radius of the electron, when the electron is at rest.It may be noted explicitly that the difficulty that has been associated with the emission of low energy quanta by “Bremsstrahlung” will not arise in the present formulation of the electromagnetic interaction between field and particles. This case is interesting since an infinity arises here which is not analogous to the self energy infinities, but occurs in the direct calculation of a physical process and not in a virtual transition.The theory seems satisfactory so far as low energy processes (< 137 mc2) are concerned and the real test of its applicability may be expected to arise in discussing processes of high energy. It is hoped to treat these in a later paper.

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Laboratory studies of electron attachment and detachment processes of aeronomic interest

Canadian Journal of Chemistry ◽

10.1139/v69-289 ◽

1969 ◽

Vol 47 (10) ◽

pp. 1783-1793 ◽

Cited By ~ 103

Author(s):

A. V. Phelps

Keyword(s):

Cross Sections ◽

Ion Beam ◽

Electron Attachment ◽

Negative Ions ◽

High Energy ◽

Low Energy ◽

Rate Coefficients ◽

Dissociative Attachment ◽

Three Body ◽

Energy Processes

Techniques for the study of electron attachment and detachment are reviewed. The rate coefficients for the various processes of aeronomic interest are then discussed. The rates of three-body and dissociative attachment by thermal electrons have been successfully determined by swarm techniques and by high frequency studies of electrons produced by high energy particles and by photoionization. Collisional and associative detachment rates for thermal energy negative ions have been measured using the swarm and flowing afterglow techniques. Radiative attachment rates for some atmospheric negative ions have been calculated from measurements of photodetachment cross sections using crossed photon and ion beam techniques. Electron beam studies and measurements of ion kinetic energy have provided much useful information regarding the dissociative attachment process and the structure of molecular negative ions. Rate coefficients for low energy processes such as the three-body attachment to O2, the radiative attachment to O, and the associative detachment of O− in collisions with various atmospheric gases are reasonably well known. Other possibly important low energy processes, such as dissociative attachment to O3, radiative attachment to O2, and the associative detachment of O2− are less well known.

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Low energy vs. high energy depositional settings and related sedimentary bodies in early Senenian rudist bearing carbonate shelves (central-southern Italy)

Géologie Méditerranéenne ◽

10.3406/geolm.2001.1685 ◽

2001 ◽

Vol 28 (1) ◽

pp. 37-40 ◽

Cited By ~ 2

Author(s):

Gabriele Carannante ◽

A. Laviano ◽

D. Ruberti ◽

Lucia Simone ◽

G. Sirna ◽

...

Keyword(s):

Southern Italy ◽

High Energy ◽

Low Energy ◽

Depositional Settings

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Transportation: Fuel Energies

10.1093/oso/9780198802297.003.0009 ◽

2017 ◽

Author(s):

Peter Rez

Keyword(s):

Energy Density ◽

Fossil Fuels ◽

High Energy ◽

Ease Of Use ◽

Low Energy ◽

High Energy Density ◽

Nuclear Fuels ◽

Liquid Hydrocarbons ◽

Transportation Fuel ◽

Journey Time

Transportation efficiency can be measured in terms of the energy needed to move a person or a tonne of freight over a given distance. For passengers, journey time is important, so an equally useful measure is the product of the energy used and the time taken for the journey. Transportation requires storage of energy. Rechargeable systems such as batteries have very low energy densities as compared to fossil fuels. The highest energy densities come from nuclear fuels, although, because of shielding requirements, these are not practical for most forms of transportation. Liquid hydrocarbons represent a nice compromise between high energy density and ease of use.

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Laser breakdown in crystalline argon as model of fast high-energy processes

Soviet Journal of Quantum Electronics ◽

10.1070/qe1979v009n01abeh008687 ◽

1979 ◽

Vol 9 (1) ◽

pp. 48-51

Author(s):

I I Ashmarin ◽

A I Andreev ◽

Yu A Bykovskiĭ ◽

V A Gridin ◽

Ya Yu Zysin

Keyword(s):

High Energy ◽

Laser Breakdown ◽

Energy Processes

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Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

International Journal of Molecular Sciences ◽

10.3390/ijms22157879 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7879

Author(s):

Yingxia Gao ◽

Yi Zheng ◽

Léon Sanche

Keyword(s):

Condensed Phase ◽

Genetic Material ◽

High Energy ◽

Dna Lesions ◽

Low Energy ◽

Experimental Investigations ◽

Experimental Conditions ◽

Strand Breaks ◽

Sequence Of Events ◽

Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

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