bluuebunny/crossref_metadata_2025_split huggingface dataset:
DC hopping photoconductivity via three-charge-state point defects in partially disordered semiconductors
Authors: Poklonski N A , Anikeev I I , Vyrko S A 
Published: November 2022

Abstract
The stationary (DC) hopping photoconductivity caused by the migration of electrons via intrinsic point t-defects of the same type with three charge states (−1, 0, and +1 in units of elementary charge) is theoretically studied. It is assumed that t-defects are randomly (Poissonian) distributed over a crystal and hops of single electrons occur only via t-defects in the charge states (−1), (0) and (0), (+1). Under the influence of intercenter illumination nonequilibrium charge states (−1) and (+1) of defects are generated due to photostimulated electron transitions between pairs of defects in the charge states (0). During the recombination of nonequilibrium charge states (−1) and (+1) of defects, pairs of defects in the charge states (0) are formed. It is assumed that illumination does not heat the crystal, i.e. does not increase the coefficient of thermal ionization of t-defects. The dependence of the ratio of photoconductivity to dark hopping electrical conductivity on the ratio of photoionization coefficient (γ) of neutral t-defects to coefficient of ‘capture’ (α) of an electron from a negatively charged to a positively charged t-defect is calculated. The calculations of hopping photoconductivity were carried out for the partially disordered silicon crystal with total concentration of t-defects of 3·1019 cm−3, compensated by shallow hydrogen-like donors. The ratios of donor concentration to t-defect concentration (compensation ratios) are 0.25, 0.5, and 0.75. It is taken into account that an electron localization radius on t-defect in the charge state (−1) is greater that on t-defect in the charge state (0). The calculated value of the dark hopping electrical conductivity is consistent with the known experimental data. A negative DC photoconduction at γ > α is predicted, due to a decrease in the concentration of electrons hopping via states (−1), (0) and (0), (+1).
Signal of cosmic strings in cross-correlation of 21-cm redshift and CMB polarization maps
Authors: Blamart Matteo , Fronenberg Hannah , Brandenberger Robert 
Published: November 2022

Abstract
We study the signal of cosmic string wakes present before the time of reionization in the cross-correlation signal of 21-cm redshift and B-mode CMB polarization maps. The specific non-Gaussian signal of strings in the position space cross-correlation maps can be extracted by means of a matched filtering analysis. Signals of strings with tension somewhat lower than those corresponding to the current upper bound can be identified when embedded in a background of Gaussian fluctuations from a Planck best-fit LCDM model.
Do you smell something decaying? Updated linear constraints on decaying dark matter scenarios
Authors: Alvi S. , Brinckmann T. , Gerbino M. , Lattanzi M. , Pagano L. 
Published: November 2022

Abstract
The stability of particles in the cosmic soup is an important property that can affect the cosmic evolution. In this work, we update the constraints on the decaying cold dark matter scenario, when the decay products are effectively massless. We assume, as a base case, that all of dark matter is unstable and it can decay on cosmological time scales. We then extend the analysis to include the scenario where only a fraction of dark matter is unstable, while the remaining part is composed of the standard, stable, dark matter. We consider observations of cosmological probes at linear scales, i.e., Planck 2018 cosmic microwave background temperature, polarization, and lensing measurements, along with geometrical information from baryon acoustic oscillation (BAO) measurements from SDSS DR7, BOSS DR12, eBOSS DR16 and 6dFGS, to derive conservative constraints on the dark matter decay rate. We consider these dataset separately, to asses the relative constraining power of each dataset, as well as together to asses the joint constraints. We find the most stringent upper limit on the decay rate of decaying cold dark matter particles to be ΓDCDM < 0.129 × 10-18 s-1 (or, equivalently, the dark matter lifetime τ
DCDM > 246 Gyr) at 95% C.L. for the combination of Planck primary anisotropies, lensing and BAO. We further explore one-parameter extensions of our baseline DCDM model. Namely, we vary the sum of neutrino masses, the curvature density parameter, and the tensor-to-scalar ratio along with the DCDM parameters. When varying the tensor-to-scalar ratio we also add data from the BICEP/Keck experiment.
Qualitative analysis for viscous cosmologies in a non linear regime of the Israel-Stewart formalism
Authors: Aguilar-Pérez Gilberto , Avilez-López Ana A. , Cruz Miguel 
Published: November 2022

Abstract
We explore the dynamical properties of a cosmological model that includes viscous effects in the dark matter sector of the fluid equations in a flat Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime. The bulk viscous effects are described by a non linear extension of the full Israel-Stewart model, which is a fluid causal scheme. We allow the interchange of energy in the dark sector and describe this by means of the interaction term, namely Q. We establish the dynamical system corresponding to Friedmann and fluid set of equations associated to the model and study the linear stability of its critical points. From the exploration of the dynamical system, we show the appearance of a critical point characterizing a de Sitter universe within the non interacting and interacting dark sector. We focus our study to analyse the stability of this fixed point in a large region of parameter space and derive linearized solutions around it. These approximate and analytical solutions are potentially able to describe the expansion of the universe since they are close to a de Sitter stationary solution. Within this regime with Q ≠ 0, we realize the existence of regions in the space of parameters where this critical point is stable and describes the behavior of dark energy as quintessence, cosmological constant and phantom like fluids. We perform a comparison between numerical and linearized solutions nearby the critical points within the full non linear regimes and also contrast them against ΛCDM model as a fiducial model. We find that the fully non linear regime is favored by observations and closer to the concordance model due to the non-zero value of the parameter j, which controls the non linear effects of bulk viscosity. In fact, at low redshift values, the expansion rate associated to the full non linear regime is practically indistinguishable from the ΛCDM model. The deceleration parameter obtained in this regime exhibits a transition from decelerated to accelerated cosmic expansion.
Cumulative fission yield measurements with 14.7 MeV neutrons on 238U*
Authors: Yang Xianlin , Lan Changlin , Nie Yangbo , Jiang Liyang , Qiu Yijia , Ge Yujie , Chen Hongtao , Zhang Kai , Wei Yuting , Wang Jiahao , Jiang Gong , Ruan Xichao , Yang Yi 
Published: November 2022

Abstract
The fission yield data in the 14 MeV energy neutron induced fission of 238U play an important role in decay heat calculations and generation-IV reactor designs. In order to accurately measure fission product yields (FPYs) of 238U induced by 14 MeV neutrons, the cumulative yields of fission products ranging from 92Sr to 147Nd in the 238U(n, f) reaction with a 14.7 MeV neutron were determined using an off-line γ-ray spectrometric technique. The 14.7 MeV quasi-monoenergetic neutron beam was provided by the K-400 D-T neutron generator at China Academy of Engineering Physics (CAEP). Fission products were measured by a low background high purity germanium gamma spectrometer. The neutron flux was obtained from the 93Nb (n, 2n)92mNb reaction, and the mean neutron energy was calculated using the cross-section ratios for the 90Zr(n, 2n)89Zr and 93Nb(n, 2n)92mNb reactions. With a series of corrections, high precision cumulative yields of 20 fission products were obtained. Our FPYs for the 238U(n, f) reaction at 14.7 MeV were compared with the existing experimental nuclear reaction data and evaluated nuclear data, respectively. The results will be helpful in the design of a generation-IV reactor and the construction of evaluated fission yield databases.
Wireless optoelectronic devices for vagus nerve stimulation in mice
Authors: Donahue Mary J , Ejneby Malin Silverå , Jakešová Marie , Caravaca April S , Andersson Gabriel , Sahalianov Ihor , Đerek Vedran , Hult Henrik , Olofsson Peder S , Głowacki Eric Daniel 
Published: November 2022

Abstract

Objective. Vagus nerve stimulation (VNS) is a promising approach for the treatment of a wide variety of debilitating conditions, including autoimmune diseases and intractable epilepsy. Much remains to be learned about the molecular mechanisms involved in vagus nerve regulation of organ function. Despite an abundance of well-characterized rodent models of common chronic diseases, currently available technologies are rarely suitable for the required long-term experiments in freely moving animals, particularly experimental mice. Due to challenging anatomical limitations, many relevant experiments require miniaturized, less invasive, and wireless devices for precise stimulation of the vagus nerve and other peripheral nerves of interest. Our objective is to outline possible solutions to this problem by using nongenetic light-based stimulation. Approach. We describe how to design and benchmark new microstimulation devices that are based on transcutaneous photovoltaic stimulation. The approach is to use wired multielectrode cuffs to test different stimulation patterns, and then build photovoltaic stimulators to generate the most optimal patterns. We validate stimulation through heart rate analysis. Main results. A range of different stimulation geometries are explored with large differences in performance. Two types of photovoltaic devices are fabricated to deliver stimulation: photocapacitors and photovoltaic flags. The former is simple and more compact, but has limited efficiency. The photovoltaic flag approach is more elaborate, but highly efficient. Both can be used for wireless actuation of the vagus nerve using light impulses. Significance. These approaches can enable studies in small animals that were previously challenging, such as long-term in vivo studies for mapping functional vagus nerve innervation. This new knowledge may have potential to support clinical translation of VNS for treatment of select inflammatory and neurologic diseases.
Approximate zero-crossing: a new interpretable, highly discriminative and low-complexity feature for EEG and iEEG seizure detection
Authors: Zanetti R , Pale U , Teijeiro T , Atienza D 
Published: November 2022

Abstract

Objective. Long-term monitoring of people with epilepsy based on electroencephalography (EEG) and intracranial EEG (iEEG) has the potential to deliver key clinical information for personalised epilepsy treatment. More specifically, in outpatient settings, the available solutions are not satisfactory either due to poor classification performance or high complexity to be executed in resource-constrained devices (e.g. wearable systems). Therefore, we hypothesize that obtaining high discriminative features is the main avenue to improve low-complexity seizure-detection algorithms. Approach. Inspired by how neurologists recognize ictal EEG data, and to tackle this problem by targeting resource-constrained wearable devices, we introduce a new interpretable and highly discriminative feature for EEG and iEEG, namely approximate zero-crossing (AZC). We obtain AZC by applying a polygonal approximation to mimic how our brain selects prominent patterns among noisy data and then using a zero-crossing count as a measure of the dominating frequency. By employing Kullback–Leiber divergence, leveraging CHB-MIT and SWEC-ETHZ iEEG datasets, we compare the AZC discriminative power against a set of 56 classical literature features (CLF). Moreover, we assess the performances of a low-complexity seizure detection method using only AZC features versus employing the CLF set. Main results. Three AZC features obtained with different approximation thresholds are among the five with the highest median discriminative power. Moreover, seizure classification based on only AZC features outperforms an equivalent CLF-based method. The former detects 102 and 194 seizures, against 99 and 161 for the latter (CHB-MIT and SWEC-ETHZ, respectively). Moreover, the AZC-based method keeps a similar false-alarm rate (i.e. an average of 2.1 and 1.0, against 2.0 and 0.5, per day). Significance. We propose a new feature and demonstrate its capability in seizure classification for both scalp and intracranial EEG. We envision the use of such a feature to improve outpatient monitoring with resource-constrained devices.
Investigation for the movement of the laser entrance hole and bubble plasmas in laser-driven hohlraum
Authors: Li Qi , Guo Liang , Li Sanwei , Li Zhichao , Deng Bo , Wang Qiangqiang , Deng Keli , Cao Zhurong , Du Huabin , Che Xinshen , Yang Yimeng , Hou Lifei , Gong Tao , Yang Dong , Yang Jiamin 
Published: November 2022

Abstract
In indirect-drive hohlraum, the heated plasmas from the
laser entrance hole (LEH) and bubbles blow radially inward with
time, which plays an important role in the evolution of hohlraum
plasmas. Previously, the boundary of the LEH and bubble plasmas is
measured using time-integrated x-ray images or x-ray images at
several discrete moments. A new experiment is conducted to study the
continuous temporal behaviors of the LEH and bubble plasmas, which
utilizes a gas-filled hohlraum truncated on one side. Compared
experiments are performed with 3 different LEH diameters (1.0 mm,
1.2 mm, and 1.4 mm). An x-ray streak camera (XSC) is employed for
the first time to diagnose the continuous temporal x-ray images of
the LEH and bubble plasmas, which are also measured by an x-ray
framing camera (XFC) at several discrete moments. The XSC and the
XFC are combined for the first time and give coincident results for
the movement of the LEH and bubble plasmas. In addition, 2 sets of
flat-response x-ray diode (FXRD) measure the total x-ray flux from
both the LEH and the open end and thus give the radiation
temperature (Tr) in the hohlraum. The Tr from the LEH end shows a
visual increase compared with that from the open end, due to the LEH
closure, which is coincident with the temporal x-ray images. This
work presents more precise and detailed description for the
continuous movement of the LEH and bubble plasmas, which is
beneficial to optimize our radiation hydrodynamic code and hohlraum
design for ignition.
Determination of the full energy peak efficiency of HPGe detector for varying soil compositions and Marinelli beaker dimensions using Artificial Neural Networks
Authors: Hossny K. , Salama E. , Mageed Karwan F. , Zair Al-Bakhat Yousif M. , ElFiki S. 
Published: November 2022

Abstract
Natural radioactivity measurement is studying the radiation
emitted naturally from any nature's components such as air, soil,
water, etc. This field of study plays an important role in public
health and safety management. Scientists and engineers can calculate
the radiation doses received by inhabitants of a certain area by
measuring the natural radioactivity in the same area. One of the
main issues facing the standard measurement procedure is determining
the appropriate volume of the sample to be taken from the area under
investigation. The volume of the investigated sample affects the
detection efficiency of the HPGe detector due to the self-shielding
effect. In this work we show how using artificial neural networks
can help in choosing the proper dimensions of the Marinelli beaker
to be used in the detection process. We used the various
compositions of soil as a case study. Results showed that artificial
neural networks were capable of finding the relation between soil
composition, Marinelli beaker dimensions, and gamma energy as inputs
and the HPGe detection efficiency as output. The developed model's
regression was 99% compared to the detection efficiency calculated
using MCNP. This will help to have a better prediction of the
detection efficiency of natural radioactivity measurements.
Progress in commissioning a neutron/X-ray radiography and tomography systems at IAEA NSIL
Authors: Gan Pingping , Abdelouahed Haifa Ben , Skukan Natko , Bily Tomas , Ridikas Danas 
Published: November 2022

Abstract
The Nuclear Science and Instrumentation Laboratory (NSIL) is currently establishing a Neutron Science Facility (NSF) based on two compact neutron generators: Deuterium-Deuterium (DD), resulting in 2.45 MeV neutrons, and Deuterium-Tritium (DT), resulting in 14.1 MeV neutrons, with maximum source intensities up to 5 × 106 n/s and 4 × 108 n/s over 4π, respectively. Neutron/X-ray radiography and tomography are two of the applications the NSF will be equipped with. In this paper, we report the state of the radiography and tomography system, and the neutron/X-ray radiography and tomography experiments we performed. Good radiographs and tomographs are obtained with X-ray. The spatial resolution of the X-ray radiography system is measured to be about 0.1 mm. The thermal neutron radiographs and fast neutron radiographs have proved that the DD neutron generator will be beneficial to demonstrate neutron radiography capabilities for educational purposes. Additionally, the detail of the collimator optimization of the DD neutron radiography was presented.
Health effects of liquid and gaseous fuels for household energy use: systematic evidence mapping
Authors: Nix Emily , Fleeman Nigel , Lorenzetti Federico , Lewis Jessica , Shen Guofeng , Abebe Lydia , Li Yaojie , Xing Ran , Maden Michelle , Duarte Rui , Bresnahan Rebecca , Williams Kendra N , Adair-Rohani Heather , Pope Daniel , Puzzolo Elisa 
Published: November 2022

Abstract
Exposure to household air pollution results in a substantial global health burden. The World Health Organization (WHO) Guidelines for Indoor Air Quality: Household Fuel Combustion stipulate emission rates for household energy devices should meet air quality guidelines and protect health. Liquefied petroleum gas (LPG), biogas, natural gas (NG), and alcohol fuels are considered clean for health due to their low emissions at the point of use. In light of the ongoing energy transition and increasing emphasis on these fuels, it is imperative to provide an updated synthesis of the impacts of these fuels on health. A systematic review was completed on the health effects of liquid and gaseous fuels for household energy use for cooking, heating, and lighting across high-, middle- and low-income countries. Comprehensive searches were undertaken in 12 international databases and selected studies were compiled into a new publicly available WHO Health Effects of Household Liquid & Gaseous Fuels Database, containing key study characteristics including pollutants and/or health outcomes measured. This database was then mapped to understand the breadth of evidence and potential gaps. From 48 130 search results, 587 studies were extracted for inclusion in the database on completion of the full-text review. Studies represented low-, middle- and high-income countries (HICs) over several decades - there has been a substantial increase in evidence from low- and middle-income countries (LMICs) published in the last decade, particularly in Asia. Most evidence focused on LPG for cooking in LMICs or NG used in HICs for cooking and heating. Women were the most studied demographic, with self-reported health outcomes and symptoms being the most common assessment method. Particulate matter and nitrogen oxides were the most monitored pollutants. A wide array of health symptoms and disease and injury outcomes were assessed, and most concerned respiratory health. This is the first time that evidence on the health effects of liquid and gaseous fuels for household energy use has been systematically catalogued and mapped. Most evidence concerned cooking and heating, with a paucity of information on the health effects from lighting. Limited evidence was available on the health effects of liquid fuels (such as alcohol fuels), with most studies concerning gaseous fuels. The WHO Health Effects of Household Liquid & Gaseous Fuels Database represents a valuable resource to enable the examination of the positive and negative health effects from these fuels.
Effect of neutral pressure on the blue core in Ar helicon plasma under an inhomogeneous magnetic field
Authors: WANG Chenwen , LIU Yang , SUN Meng , ZHANG Tianliang , XIE Junfa , CHEN Qiang , ZHANG Haibao 
Published: November 2022

Abstract
The effect of neutral pressure on the blue core in Ar helicon plasma under an inhomogeneous magnetic field was investigated in this work. The neutral pressure was set to 0.08 Pa, 0.36 Pa, and 0.68 Pa. A Nikon camera, intensified charge-coupled device (ICCD), optical emission spectrometer (OES), and Langmuir probe were used to diagnose the blue core in helicon plasma. Helicon plasma discharges experienced density jumps from the E mode, H mode to W mode before power just rose to 200 W. The plasma density increased and maintained a central peak with the increase of neutral pressure. However, the brightness of the blue core gradually decreased. It is demonstrated that the relative intensity of Ar II spectral lines and the ionization rate in the central area were reduced. Radial electron temperature profiles were flattened and became hollow as neutral pressure increased. It is demonstrated that increasing the neutral pressure weakened the central heating efficiency dominated by the helicon wave and strengthened the edge heating efficiency governed by the TG wave and skin effect. Therefore, the present experiment successfully reveals how the neutral pressure affects the heating mechanism of helicon plasma in an inhomogeneous magnetic field.
An analysis and preliminary experiment of the discharge characteristics of RF ion source with electromagnetic shielding
Authors: WANG Na , LIU Zhimin , XIE Yahong , WEI Jianglong , JIANG Caichao , LIU Wei , PENG Xufeng , SU Guojian , XIE Junwei 
Published: November 2022

Abstract
Combined with two-dimensional (2D) and three-dimensional (3D) finite element analysis and preliminary experimental tests, the effects of size and placement of the electromagnetic shield of the radio-frequency (RF) ion source with two drivers on plasma parameters and RF power transfer efficiency are analyzed. It is found that the same input direction of the current is better for the RF ion source with multiple drivers. The electromagnetic shield (EMS) should be placed symmetrically around the drivers, which is beneficial for the plasma to distribute uniformly and symmetrically in both drivers. Furthermore, the bigger the EMS shield radius is the better generating a higher electron density. These results will be of guiding significance to the design of electromagnetic shielding for RF ion sources with a multi-driver.
Review of the structure and performance of through-holed anodes and cathodes prepared with a picosecond pulsed laser for lithium-ion batteries
Authors: Matsumoto Futoshi , Yamada Mitsuru , Tsuta Masaya , Nakamura Susumu , Ando Nobuo , Soma Naohiko 
Published: November 2022

Abstract
To move the performance of lithium-ion batteries into the next stage, the modification of the structure of cells is the only choice except for the development of materials exhibiting higher performance. In this review paper, the employment of through-holing structures of anodes and cathodes prepared with a picosecond pulsed laser has been proposed. The laser system and the structure for improving the battery performance were introduced. The performance of laminated cells constructed with through-holed anodes and cathodes was reviewed from the viewpoints of the improvement of high-rate performance and energy density, removal of unbalanced capacities on both sides of the current collector, even greater high-rate performance by hybridizing cathode materials and removal of irreversible capacity. In conclusion, the points that should be examined and the problem for the through-holed structure to be in practical use are summarized.