The transport behavior of potassium ions through carbon nanotubes (CNTs) under the effect of moving surface charges is studied by using non-equilibrium molecular dynamics and the Monte Carlo method. ...Two motion patterns of the surface charges, axial translation and radial vibration, are investigated. We found that when the surface charge is translated in the axial direction, there is an optimal translation velocity to maximize the particle flow density (
PFD
), and the specific value of this optimal translation velocity is related to the surface charge period and the charge amount. When the surface charge vibrates in the radial direction, the
PFD
under the negative charge presents a step-type-decrease trend with an increase of the vibration frequency, and the trend is independent from the charge amount and the vibrating period. Our results provide new ideas for nanoscale transport devices and also provide possible insights into the transport mechanisms of biological ion channels.
Using non-equilibrium molecular dynamics and Monte Carlo methods, we have studied the transport diffusion of gas in deformed carbon nanotubes. Perfect carbon nanotube and various deformed carbon ...nanotubes are modeled as transport channels. It is found that the transport diffusion coefficient of gas does not change in twisted carbon nanotubes, but changes in XY-distortion, Z-distortion and local defect carbon nanotubes comparing with that of the perfect carbon nanotube. Furthermore, the change of transport diffusion coefficient is found to be associated with the deformation factor. The relationship between transport diffusion coefficient and temperature is also discussed in this paper. Our results may contribute to understanding the mechanism of molecular transport in nano-channel.
•A three dimensional system is built to study the transport diffusion by molecular dynamic methods.•Perfect and various deformed Carbon nanotubes are employed as the channels.•The effects of deformation types and degree on transport diffusion are studied.•The reasons of diffusion coefficient difference are also analyzed.•The results provide some valuable suggestions for designing nano-devices.
Calibration strategy of the JUNO experiment An, Fengpeng; Andronico, Giuseppe; Bernieri, Enrico ...
The journal of high energy physics,
03/2021, Volume:
2021, Issue:
3
Journal Article
Peer reviewed
Open access
A
bstract
We present the calibration strategy for the 20 kton liquid scintillator central detector of the Jiangmen Underground Neutrino Observatory (JUNO). By utilizing a comprehensive ...multiple-source and multiple-positional calibration program, in combination with a novel dual calorimetry technique exploiting two independent photosensors and readout systems, we demonstrate that the JUNO central detector can achieve a better than 1% energy linearity and a 3% effective energy resolution, required by the neutrino mass ordering determination.
A
bstract
JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear ...power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day (cpd), therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration to reduce at minimum the impact of natural radioactivity. We describe our efforts for an optimized experimental design, a careful material screening and accurate detector production handling, and a constant control of the expected results through a meticulous Monte Carlo simulation program. We show that all these actions should allow us to keep the background count rate safely below the target value of 10 Hz (i.e.
∼
1 cpd accidental background) in the default fiducial volume, above an energy threshold of 0.7 MeV.
The OSIRIS detector is a subsystem of the liquid scintillator filling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all ...components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of
10
-
16
g/g
of
238
U
and
232
Th
requires a large (
∼
20
m
3
) detection volume and ultralow background levels. The present paper reports on the design and major components of the OSIRIS detector, the detector simulation as well as the measuring strategies foreseen and the sensitivity levels to U/Th that can be reached in this setup.
Atmospheric neutrinos are one of the most relevant natural neutrino sources that can be exploited to infer properties about cosmic rays and neutrino oscillations. The Jiangmen Underground Neutrino ...Observatory (JUNO) experiment, a 20 kton liquid scintillator detector with excellent energy resolution is currently under construction in China. JUNO will be able to detect several atmospheric neutrinos per day given the large volume. A study on the JUNO detection and reconstruction capabilities of atmospheric
ν
e
and
ν
μ
fluxes is presented in this paper. In this study, a sample of atmospheric neutrino Monte Carlo events has been generated, starting from theoretical models, and then processed by the detector simulation. The excellent timing resolution of the 3” PMT light detection system of JUNO detector and the much higher light yield for scintillation over Cherenkov allow to measure the time structure of the scintillation light with very high precision. Since
ν
e
and
ν
μ
interactions produce a slightly different light pattern, the different time evolution of light allows to discriminate the flavor of primary neutrinos. A probabilistic unfolding method has been used, in order to infer the primary neutrino energy spectrum from the detector experimental observables. The simulated spectrum has been reconstructed between 100 MeV and 10 GeV, showing a great potential of the detector in the atmospheric low energy region.
We proposed a nanoscale water switch composed of CNTs. A capped CNT with potassium ions in it may move under an external electric field, just like a piston. We can control the switch toggle between ...the open and closed states only by changing the direction of the external electric field. Molecular dynamics (MD) was used to simulate the performance of the switch. The results show that this device may act well as a switch. The response speed of the switch reaches the nanosecond level. The stability of the piston position is also investigated.
We proposed a nano-scale water switch composed of CNTs. We can control the switch toggle between open and close state only by changing the direction of the external electric field.
Intensifying variability in precipitation under a changing climate is projected to amplify fluctuation in terrestrial hydrological cycle, leading to more severe water-related disasters. The ...connections between interannual variability of hydrological components and factors influencing these connections have not been clearly defined yet. Based on terrestrial water budget from Climate Data Record, we identify dominant factors influencing partitioning interannual variability of precipitation (P) into that of evapotranspiration (E), runoff (Q), and water storage deviation (ΔS) across the globe by employing geographical detector model (GDM). Sensitivities of the variability partitioning to dominant factors are quantified for different hydroclimate regions by linear regression model and law of total differential. Results show that dominant factors influencing precipitation variability partitioning (VP) are different across distinct hydroclimate conditions. Comparing the statistical index (q value) of the GDM, it can be seen that surface air temperature (Ta), snow water equivalent (SWE) and water storage capacity (Smax) are dominant factors of VP in humid, semi-arid and arid regions, respectively. Changes in P variability largely can transfer into Q variability in humid region. The P variability partitioned into Q variability is dramatically reduced in semi-arid region with SWE decreasing, while P variability partitioned into ΔS variability increases with Smax increasing in arid region. Joint effects of Ta and coefficient of variation of precipitation (Pcv) are found to be the most important interaction in determining VP across the globe. Furthermore, warmer temperatures in humid region cause >90 % of the change in precipitation variability to be transferred to Q variability change. In semi-arid region with snowfall, decreased SWE has strong effect on changes in ΔS (30–40 %) and Q (20–40 %) variability. Our findings imply a changing VP and more severe impacts of hydrological extremes under future climate, where intensive changes in Ta, SWE and land cover are projected.
Display omitted
•Factors affecting precipitation variability partition (VP) are found in the globe.•Changes in precipitation variability mainly shift to runoff in warmer humid region.•Snow water equivalent is a key factor that affects VP in semi-arid region.•In arid region, water storage capacity has critical impact on VP.
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