scholarly journals Highly luminescent hetero-ligand MOF nanocrystals with engineered massive Stokes shift for photonic applications.

2021 ◽  
Author(s):  
Jacopo Perego ◽  
Charl Bezuidenhout ◽  
Irene Villa ◽  
Francesca Cova ◽  
Roberta Crapanzano ◽  
...  
Keyword(s):  
High Efficiency ◽  
Stokes Shift ◽  
Building Blocks ◽  
High Energy ◽  
Radiative Energy ◽  
Fast Diffusion ◽  
High Energy Radiation ◽  
Radiative Energy Transfer ◽  
Molecular Length ◽  
Molecular Excitons

A high efficiency emission with a massive Stokes shift is obtained by fluorescent conjugated acene building blocks arranged in nanocrystals. The two ligands of equal molecular length and connectivity, yet complementary electronic properties, are co-assembled by zirconium oxy-hydroxy clusters, generating highly crystalline hetero-MOF nanoparticles The fast diffusion of singlet molecular excitons in the framework, coupled with the fine matching of ligands absorption and emission properties, enables to achieve an ultrafast activation of the low energy emission by diffusion-mediated non-radiative energy transfer in the 100 ps time scale, by using a low amount of co-ligands. This allow to obtain MOF nanocrystals with a fluorescence quantum efficiency of ̴ 70% and an actual Stokes shift as large as 750 meV. This large Stokes shift suppresses the reabsorption of fast emission issues in bulk devices, pivotal for a plethora of applications in photonics and photon managing spacing from solar technologies, imaging, and detection of high energy radiation. These features allowed to realize a prototypal fast nanocomposite scintillator that shows an enhanced performance with respect to the homo-ligand nanocrystals, achieving benchmark. values which compete with those of some inorganic and organic commercial systems.

scholarly journals Engineering Spiking Neurons Using Threshold Switching Devices for High-Efficient Neuromorphic Computing

2022 ◽  
Vol 15 ◽  
Author(s):  
Yanting Ding ◽  
Yajun Zhang ◽  
Xumeng Zhang ◽  
Pei Chen ◽  
Zefeng Zhang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
High Efficiency ◽  
Building Blocks ◽  
High Energy ◽  
Spiking Neurons ◽  
Input Intensity ◽  
Practical Applications ◽  
Intrinsic Factors ◽  
Threshold Switching ◽  
High Efficient

Inspired by the human brain, the spike-based neuromorphic system has attracted strong research enthusiasm because of the high energy efficiency and powerful computational capability, in which the spiking neurons and plastic synapses are two fundamental building blocks. Recently, two-terminal threshold switching (TS) devices have been regarded as promising candidates for building spiking neurons in hardware. However, how circuit parameters affect the spiking behavior of TS-based neurons is still an open question. Here, based on a leaky integrate-and-fire (LIF) neuron circuit, we systematically study the effect of both the extrinsic and intrinsic factors of NbOx -based TS neurons on their spiking behaviors. The extrinsic influence factors contain input intensities, connected synaptic weights, and parallel capacitances. To illustrate the effect of intrinsic factors, including the threshold voltage, holding voltage, and high/low resistance states of NbOx devices, we propose an empirical model of the fabricated NbOx devices, fitting well with the experimental results. The results indicate that with enhancing the input intensity, the spiking frequency increases first then decreases after reaching a peak value. Except for the connected synaptic weights, all other parameters can modulate the spiking peak frequency under high enough input intensity. Also, the relationship between energy consumption per spike and frequency of the neuron cell is further studied, leading guidance to design neuron circuits in a system to obtain the lowest energy consumption. At last, to demonstrate the practical applications of TS-based neurons, we construct a spiking neural network (SNN) to control the cart-pole using reinforcement learning, obtaining a reward score up to 450. This work provides valuable guidance on building compact LIF neurons based on TS devices and further bolsters the construction of high-efficiency neuromorphic systems.

Electron and Positron Beam–Driven Plasma Acceleration

2016 ◽  
Vol 09 ◽  
pp. 63-83 ◽  
Author(s):  
Mark J. Hogan
Keyword(s):  
High Efficiency ◽  
Positron Beam ◽  
Building Blocks ◽  
Plasma Waves ◽  
High Energy ◽  
Resolving Power ◽  
Particle Accelerators ◽  
Wakefield Acceleration ◽  
Electrons And Positrons ◽  
Plasma Wakefield

Particle accelerators are the ultimate microscopes. They produce high energy beams of particles — or, in some cases, generate X-ray laser pulses — to probe the fundamental particles and forces that make up the universe and to explore the building blocks of life. But it takes huge accelerators, like the Large Hadron Collider or the two-mile-long SLAC linac, to generate beams with enough energy and resolving power. If we could achieve the same thing with accelerators just a few meters long, accelerators and particle colliders could be much smaller and cheaper. Since the first theoretical work in the early 1980s, an exciting series of experiments have aimed at accelerating electrons and positrons to high energies in a much shorter distance by having them “surf” on waves of hot, ionized gas like that found in fluorescent light tubes. Electron-beam-driven experiments have measured the integrated and dynamic aspects of plasma focusing, the bright flux of high energy betatron radiation photons, particle beam refraction at the plasma–neutral-gas interface, and the structure and amplitude of the accelerating wakefield. Gradients spanning kT/m to MT/m for focusing and 100[Formula: see text]MeV/m to 50[Formula: see text]GeV/m for acceleration have been excited in meter-long plasmas with densities of 10[Formula: see text]–10[Formula: see text][Formula: see text]cm[Formula: see text], respectively. Positron-beam-driven experiments have evidenced the more complex dynamic and integrated plasma focusing, 100[Formula: see text]MeV/m to 5[Formula: see text]GeV/m acceleration in linear and nonlinear plasma waves, and explored the dynamics of hollow channel plasma structures. Strongly beam-loaded plasma waves have accelerated beams of electrons and positrons with hundreds of pC of charge to over 5[Formula: see text]GeV in meter scale plasmas with high efficiency and narrow energy spread. These “plasma wakefield acceleration” experiments have been mounted by a diverse group of accelerator, laser and plasma researchers from national laboratories and universities around the world. This article reviews the basic principles of plasma wakefield acceleration with electron and positron beams, the current state of understanding, the push for first applications and the long range R&D roadmap toward a high energy collider.

Photo-degradation of monoazo dye blue 13 using advanced oxidation process

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Aqueous Solution ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
High Energy ◽  
Uv Exposure ◽  
H2o2 Concentration ◽  
Oxidizing Agent ◽  
Photo Degradation ◽  
High Energy Radiation ◽  
Uv Lamp

The high energy radiation overcome the bonding of solute in a solution and H2O2 acts as an oxidizing agent and generates a free radical in the solution which results in photo-degradation by converting the solute in to simple form and resultantly, colored substance under the effect of photo-degradation becomes colorless. The photo-degradation of monoazo dye Blue 13 in an aqueous solution was investigated using a laboratory scale UV lamp in the presence of H2O2 and for maximum degradation of dye, the independent parameter UV power, UV exposure time, pH and H2O2 concentration were optimized. It was found that neither UV in the presence of H2O2 is able to degrade Blue 13 under optimum condition. The results revealed that the use of both UV and H2O2 have pronounced effect on the discoloration of dyes which could be used for management of textile effluents contain waste dyes.

Electrochemical Oxidative Esterification of Thiophenols: Efficient Access to Sulfinic Esters

2020 ◽  
Vol 17 (7) ◽  
pp. 540-547
Author(s):  
Chun-Hui Yang ◽  
Cheng Wu ◽  
Jun-Ming Zhang ◽  
Xiang-Zhang Tao ◽  
Jun Xu ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Efficient Method ◽  
High Efficiency ◽  
Building Blocks ◽  
Constant Current ◽  
Good Efficiency ◽  
Oxidative Esterification ◽  
Efficient Access ◽  
New Applications ◽  
Sulfinic Esters

Background: The sulfinic esters are important and useful building blocks in organic synthesis. Objective: The aim of this study was to develop a simple and efficient method for the synthesis of sulfinic esters. Materials and Methods: Constant current electrolysis from thiols and alcohols was selected as the method for the synthesis of sulfinic esters. Results and Discussion: A novel electrochemical method for the synthesis of sulfinic esters from thiophenols and alcohols has been developed. Up to 27 examples of sulfinic esters have been synthesized using the current methods. This protocol shows good functional group tolerance as well as high efficiency. In addition, this protocol can be easily scaled up with good efficiency. Notably, heterocycle-containing substrates, including pyridine, thiophene, and benzothiazole, gave the desired products in good yields. A plausible reaction mechanism is proposed. Conclusion: This research not only provides a green and efficient method for the synthesis of sulfinic esters but also shows new applications of electrochemistry in organic synthesis. It is considered that this green and efficient synthetic protocol used to prepare sulfinic esters will have good applications in the future.

scholarly journals Challenges and Opportunities for CsPbBr3 Perovskites in Low- and High-Energy Radiation Detection

2021 ◽  
pp. 1290-1314
Author(s):  
Lotte Clinckemalie ◽  
Donato Valli ◽  
Maarten B. J. Roeffaers ◽  
Johan Hofkens ◽  
Bapi Pradhan ◽  
...  
Keyword(s):  
Radiation Detection ◽  
High Energy ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Challenges And Opportunities

scholarly journals Signatures of the Carrier Envelope Phase in Nonlinear Thomson Scattering

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 528
Author(s):  
Marcel Ruijter ◽  
Vittoria Petrillo ◽  
Thomas C. Teter ◽  
Maksim Valialshchikov ◽  
Sergey Rykovanov
Keyword(s):  
Laser Pulse ◽  
Radiation Spectrum ◽  
Thomson Scattering ◽  
High Energy ◽  
Phase Changes ◽  
High Energy Radiation ◽  
Carrier Envelope Phase ◽  
High Intensity Laser ◽  
Experimental Parameters ◽  
Intensity Laser

High-energy radiation can be generated by colliding a relativistic electron bunch with a high-intensity laser pulse—a process known as Thomson scattering. In the nonlinear regime the emitted radiation contains harmonics. For a laser pulse whose length is comparable to its wavelength, the carrier envelope phase changes the behavior of the motion of the electron and therefore the radiation spectrum. Here we show theoretically and numerically the dependency of the spectrum on the intensity of the laser and the carrier envelope phase. Additionally, we also discuss what experimental parameters are required to measure the effects for a beamed pulse.

Ultrasmall Gd@Cdots as a Radiosensitizing Agent for Non-Small Cell Lung Cancer

Nanoscale ◽  
2021 ◽  
Author(s):  
Chaebin Lee ◽  
Xiangji Liu ◽  
Weizhong Zhang ◽  
M. A. Duncan ◽  
Fangchao Jiang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Small Cell Lung Cancer ◽  
Cross Section ◽  
Cell Lung Cancer ◽  
High Energy ◽  
Small Cell ◽  
Small Cell Lung ◽  
High Energy Radiation ◽  
Energy Radiation

High-Z nanoparticles (HZNPs) afford high cross-section for high energy radiation and have attracted wide attention as a novel type of radiosensizers. However, conventional HZNPs are often associated with issues such...

Non-radiative energy transfer in aqueously dispersed polymeric nanoparticles for photovoltaic applications

2021 ◽  
Vol 275 ◽  
pp. 116740
Author(s):  
Maiara de Jesus Bassi ◽  
Luana Wouk ◽  
Wesley Renzi ◽  
Camilla Karla Oliveira ◽  
José Leonil Duarte ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Polymeric Nanoparticles ◽  
Radiative Energy ◽  
Radiative Energy Transfer ◽  
Photovoltaic Applications
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