bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study and improvement of the dynamic performance of dilation x-ray imager
Authors: Wang Qiangqiang , Cao Zhurong , Chen Tao , Deng Bo , Deng Keli , Tian Jinshou
Published: December 2021

We present in this Note a numerical study on the dynamic performance of a Dilation X-ray Imager (DIXI). The DIXI including a photoelectron tube (PT) and a magnetic solenoid is modeled in 3D space. The initial parameters of the photoelectrons are sampled with a Monte Carlo code. The trajectories of the photoelectrons are calculated by using the particle-in-cell method, and the transit time spread (TTS) and temporal magnification are analyzed in detail. We have designed a PT with a double-microstrip structure and compared the performance of the double-microstrip PT with the traditional single-microstrip PT. The results show that the sensitivity of the TTS and the temporal magnification to the emission time of the photoelectrons can be significantly reduced by using the double-microstrip PT, resulting in an improvement of the time window. Therefore, the dynamic performance of the DIXI is improved.
Expansion characteristics of a discharge column in an electrode–ice gap
Authors: Hu Jianlin , Meng Wei , Wang Xiaofeng , Zhang Ruihe , Sun Keer , Jiang Xingliang
Published: December 2021

When modeling the propagation of an electric discharge on an ice-covered insulator, the diameter and temperature of the discharge column are vitally important. This paper studies the thermal expansion characteristics of a discharge column occurring after electrode–ice gap breakdown both experimentally and theoretically. It is found that the air part of the discharge channel expands faster and has a higher temperature and larger diameter than the surface part. To provide a quantitative explanation of this phenomenon, a physical model is established based on the gap breakdown process, discharge channel heat conduction, and molecular thermal relaxation theory. The results of theoretical calculations show that the experimentally observed differences in discharge column thermal expansion characteristics result from the heating effect of brush discharge and from differences in heat conduction around the column.
Response of reactive species generation and biological inactivation to electromagnetically assisted cold plasma jets
Authors: Xu Han , Guo Shaoshuai , Zhang Hao , Liu Dingxin , Xie Kai
Published: December 2021

External static electric and magnetic fields aligned parallel to the propagation direction of a plasma jet affect its dynamic characteristics and the response of reactive species present. A positive electric field was shown to enhance the intensity of ionization waves and the number of positive ions, thereby promoting the generation of aqueous OH and the inactivation of tumor cells subjected to the plasma jet. Correspondingly, the concentration of aqueous O2− and sterilization by the plasma jet gradually increase with increasing negative electric field intensity. The application of an external magnetic field induces a deformation of the plasma plume, manifesting specifically as a radial contraction/expansion of the plasma plume inside/outside the quartz tube because of the influence of magnetic pressure. In addition, with the external magnetic field, the generation of reactive species and the biological inactivation within the plasma jet are improved and can be attributed to the enhanced discharge arising mainly from electrons confined by the axial magnetic field and the radial magnetic pressure. Our work shows that external magnetic fields are well suited to improving the energy efficiency with regard to plasma jet applications, whereas external electric fields provide a means to manipulate the flux and composition of reactive species over the substrate downstream.
Flexible perovskite nanosheet-based photodetectors for ultraviolet communication applications
Authors: Li Cheng-Yao , He Jie , Zhou Yi , Qi Dong-Xiang , Jing Hao , Su Jing , Peng Ru-Wen , Fan Ren-Hao , Huo Pengcheng , Xu Ting , Wang Mu
Published: December 2021

Ultraviolet (UV) photodetection has attracted much attention for applications like monitoring ozone holes and light communication. Although UV photodetectors based on conventional inorganic semiconductors have been widely investigated, fast response devices with high sensitivity remain needed for UV communication systems. This Letter reports on flexible ultrathin methylammonium lead bromide(MAPbBr3)-based UV photodetectors. In the UV regime, the response time reaches 3.3/4.0 μs, and the 3 dB bandwidth is 0.22 MHz. No current degradation is detected after repeated bending cycles, indicating the excellent mechanical flexibility and reliability of flexible high-speed UV photodetectors. Moreover, MAPbBr3 nanosheet-based photodetectors have been integrated into a UV communication system as signal receivers transmitting messages encrypted by international Morse codes. These results reveal the potential of ultrathin perovskite nanosheets in developing flexible optoelectronic devices for UV communications and related applications.
Multi-channel optical hybrid filter controlled by extrinsic parameters in various phases of Eu3+:BiPO4
Authors: Mujahid Anas , Imran Muhammad , Fan Huanrong , Yuan Taoli , Ali Hasnain , Li Peng , Zhang Yanpeng
Published: December 2021

We propose a multi-channel optical hybrid filter which can regulate into a single-channel narrowband filter (SCNBF), hybrid band filter (HBF), and the dual-channel narrow band filter (DCNBF) when the input is a broad signal. The multi-channel optical hybrid filter results from the multiple evolutions of the spectral linewidth of fluorescence (FL) signal and Stokes signal generated by the spontaneous four-wave mixing. These evolutions can be controlled by changing the extrinsic parameters (i.e., gate position, gate width, laser power, and detuning) in various phases of europium-doped BPO (Eu3+:BiPO4) as the extrinsic parameters manipulate the ratio of FL and Stokes in the composite signal (FL + Stokes) and select the energy levels. The composite signal contents vary as per the linewidth through the out-of-phase and in-phase k-vectors due to destructive and constructive interferences. The maximum bandwidth contrast we attained was 91% for SCNBF, 49% and 85% for HBF, and 90% and 88% for DCNBF.
Bridging atomistic simulations and thermodynamic hydration models of aqueous electrolyte solutions
Authors: Wang Xiangwen , Clegg Simon L. , Di Tommaso Devis
Published: December 2021

Chemical thermodynamic models of solvent and solute activities predict the equilibrium behavior of aqueous solutions. However, these models are semi-empirical. They represent micro-scale ion and solvent behaviors controlling the macroscopic properties using small numbers of parameters whose values are obtained by fitting to activities and other partial derivatives of the Gibbs energy measured for the bulk solutions. We have conducted atomistic simulations of aqueous electrolyte solutions (MgCl2 and CaCl2) to determine the parameters of thermodynamic hydration models. We have implemented a cooperative hydration model to categorize the water molecules in electrolyte solutions into different subpopulations. The value of the electrolyte-specific parameter, k, was determined from the ion-affected subpopulation with the lowest absolute value of the free energy of removing the water molecule. The other equilibrium constant parameter, K1, associated with the first degree of hydration, was computed from the free energy of hydration of hydrated clusters. The hydration number, h, was determined from a reorientation dynamic analysis of the water subpopulations compared to bulk-like behavior. The reparameterized models [R. H. Stokes and R. H. Robinson, J. Solution Chem. 2, 173 (1973) and Balomenos et al., Fluid Phase Equilib. 243, 29 (2006)] using the computed values of the parameters lead to the osmotic coefficients of MgCl2 solutions that are consistent with measurements. Such an approach removes the dependence on the availability of experimental data and could lead to aqueous thermodynamic models capable of estimating the values of solute and solvent activities as well as thermal and volumetric properties for a wide range of compositions and concentrations.
Nb2O5 high-k dielectric enabled electric field engineering of β-Ga2O3 metal–insulator–semiconductor (MIS) diode
Authors: Tiwari Prabhans , Biswas Jayeeta , Joishi Chandan , Lodha Saurabh
Published: December 2021

We demonstrate an Nb2O5/β-Ga2O3 metal–insulator–semiconductor (MIS) hetero-junction diode with Nb2O5 as the high-k dielectric insulator for more efficient electric field management resulting in enhanced breakdown characteristics compared to a β-Ga2O3 Schottky barrier diode. Nb2O5 dielectric films were grown using atomic layer deposition and exhibited a high dielectric constant of 50. The high dielectric constant resulted in a 5× lower electric field at the metal/dielectric interface in the MIS diode compared to the metal/β-Ga2O3 interface in the Schottky barrier diode. With good electron conduction in forward bias enabled by the negative conduction band offset of Nb2O5 with respect to β-Ga2O3, the MIS design led to a 3× improvement in the reverse blocking voltage with a slight trade-off in the specific on-resistance. Overall, a 3.3× increase in the power figure of merit was observed (3.25 MW/cm2 for the Schottky diode and 10.8 MW/cm2 for the MIS diode). A detailed analysis of the energy band line-up and the forward and reverse current transport mechanisms are also presented using analytical modeling and 2D technology computer-aided design simulations.
Energetics of the charge generation in organic donor–acceptor interfaces
Authors: Andermann Artur M. , Rego Luis G. C.
Published: December 2021

Non-fullerene acceptor materials have posed new paradigms for the design of organic solar cells , whereby efficient carrier generation is obtained with small driving forces, in order to maximize the open-circuit voltage (VOC). In this paper, we use a coarse-grained mixed quantum–classical method, which combines Ehrenfest and Redfield theories, to shed light on the charge generation process in small energy offset interfaces. We have investigated the influence of the energetic driving force as well as the vibronic effects on the charge generation and photovoltaic energy conversion. By analyzing the effects of the Holstein and Peierls vibrational couplings, we find that vibrational couplings produce an overall effect of improving the charge generation. However, the two vibronic mechanisms play different roles: the Holstein relaxation mechanism decreases the charge generation, whereas the Peierls mechanism always assists the charge generation. Moreover, by examining the electron–hole binding energy as a function of time, we evince two distinct regimes for the charge separation: the temperature independent excitonic spread on a sub-100 fs timescale and the complete dissociation of the charge-transfer state that occurs on the timescale of tens to hundreds of picoseconds, depending on the temperature. The quantum dynamics of the system exhibits the three regimes of the Marcus electron transfer kinetics as the energy offset of the interface is varied.
Stochastic configuration networks with fast implementations
Authors: Tian Zhongda , Zhang Haobo
Published: December 2021

Stochastic configuration networks (SCNs) employ a supervisory mechanism to assign hidden-node parameters in the incremental construction process. SCNs offer the advantages of practical implementation, fast convergence, and better generalization performance. However, due to its high computational cost and the scalability of numerical algorithms for the least square technique, it is rather limited for dealing with enormous amounts of data. This paper proposes fast SCNs (F-SCNs), whose output weights are determined using orthogonal matrix Q and upper triangular matrix R decomposition. The network can iteratively update the output weights utilizing the output information from the predecessor node using this incremental technique. We investigated the computational complexity of SCNs and F-SCNs and demonstrated that F-SCNs are suitable for scenarios in which the hidden layer has a significant number of nodes. We evaluated the proposed method on four real-world regression datasets; experimental results show that our method has notable advantages in terms of speed and effectiveness of learning.
Sarm1 activation produces cADPR to increase intra-axonal Ca++ and promote axon degeneration in PIPN
Authors: Li Yihang , Pazyra-Murphy Maria F. , Avizonis Daina , de Sá Tavares Russo Mariana , Tang Sophia , Chen Chiung-Ya , Hsueh Yi-Ping , Bergholz Johann S. , Jiang Tao , Zhao Jean J. , Zhu Jian , Ko Kwang Woo , Milbrandt Jeffrey , DiAntonio Aaron , Segal Rosalind A.
Published: December 2021

Cancer patients frequently develop chemotherapy-induced peripheral neuropathy (CIPN), a painful and long-lasting disorder with profound somatosensory deficits. There are no effective therapies to prevent or treat this disorder. Pathologically, CIPN is characterized by a “dying-back” axonopathy that begins at intra-epidermal nerve terminals of sensory neurons and progresses in a retrograde fashion. Calcium dysregulation constitutes a critical event in CIPN, but it is not known how chemotherapies such as paclitaxel alter intra-axonal calcium and cause degeneration. Here, we demonstrate that paclitaxel triggers Sarm1-dependent cADPR production in distal axons, promoting intra-axonal calcium flux from both intracellular and extracellular calcium stores. Genetic or pharmacologic antagonists of cADPR signaling prevent paclitaxel-induced axon degeneration and allodynia symptoms, without mitigating the anti-neoplastic efficacy of paclitaxel. Our data demonstrate that cADPR is a calcium-modulating factor that promotes paclitaxel-induced axon degeneration and suggest that targeting cADPR signaling provides a potential therapeutic approach for treating paclitaxel-induced peripheral neuropathy (PIPN).
Monoelemental two-dimensional iodinene nanosheets: a first-principles study of the electronic and optical properties
Authors: Bafekry A , Stampfl C , Faraji M , Mortazavi B , Fadlallah M M , Nguyen Chuong V , Fazeli S , Ghergherehchi M
Published: December 2021

Very recently, two-dimensional (2D) iodinene, a novel layered and buckled structure has been successfully fabricated (Qian et al 2020 Adv. Mater.
32 2004835). Motivated by this latest experimental accomplishment, for the first time we conduct density functional theory, first-principles calculations to explore the structural, electronic, and optical properties of monolayer, few-layer and bulk iodinene. Unlike the majority of monoelemental 2D lattices, iodinene is predicted to be an intrinsic semiconductor. On the basis of calculations using the generalized gradient approximation of Perdew–Burke–Ernzerhof for the exchange-correlation functional and the Heyd-Scuseria-Ernzerhof (HSE06) functional, it is shown that the electronic bandgap of iodinene decreases with increasing the number of atomic layers. Our HSE06 results reveal that the bandgap of iodinene decreases from 2.08 to 1.28 eV as the number of atomic layers change from one to five, highlighting the finely tunable bandgap. The optical study shows the monolayer has the ability to absorb a wide range of ultraviolet light, more than multilayers and bulk iodinene. As the number of layers increases, the absorption spectra exhibits a blue shift relative to monolayer iodinene. This study confirms the remarkable prospect for the application of iodinene in nanoelectronics and optoelectronics owing to its intrinsic semiconducting nature.
Interaction of molecular tori in columnar structures
Authors: Lun-Fu Alexandr , Bubenchikov Mikhail , Bubenchikov Alexey , Mamontov Dmitriy , Borodin Vladislav
Published: December 2021

The potential of tori interactions, simple in form, is obtained, which underlies the mechanisms of the formation of molecular associations in liquid crystals. In the considered linear aggregates, the short-range interactions of the tori are calculated. The dynamic state of a hexagonal tori cord is also considered.
3D total variation denoising in X-CT imaging applied to pore extraction in additively manufactured parts
Authors: Heylen Rob , Thanki Aditi , Verhees Dries , Iuso Domenico , De Beenhouwer Jan , Sijbers Jan , Witvrouw Ann , Haitjema Han , Bey-Temsamani Abdellatif
Published: December 2021

X-ray computed tomography (X-CT) plays an important role in non-destructive quality inspection and process evaluation in metal additive manufacturing, as several types of defects such as keyhole and lack of fusion pores can be observed in these 3D images as local changes in material density. Segmentation of these defects often relies on threshold methods applied to the reconstructed attenuation values of the 3D image voxels. However, the segmentation accuracy is affected by unavoidable X-CT reconstruction features such as partial volume effects, voxel noise and imaging artefacts. These effects create false positives, difficulties in threshold value selection and unclear or jagged defect edges. In this paper, we present a new X-CT defect segmentation method based on preprocessing the X-CT image with a 3D total variation denoising method. By comparing the changes in the histogram, threshold selection can be significantly better, and the resulting segmentation is of much higher quality. We derive the optimal algorithm parameter settings and demonstrate robustness for deviating settings. The technique is presented on simulated data sets, compared between low- and high-quality X-CT scans, and evaluated with optical microscopy after destructive tests.
Iron vacancies engineering of Fe
x
C@NC hybrids toward enhanced lithium-ion storage properties
Authors: Liu Shenghong , Zheng Wenrui , Huang Mingyue , Xu Yaning , Xie Wenhe , Sun Haibin , Zhao Yanming
Published: December 2021

Defect engineering have profound influence on the energy storage properties of electrode hybrids by adjusting their intrinsic electronic characteristics. For iron carbide based materials, however, the effect of defect (especially cation vacancies) toward their electrochemical performance are still unclear. Herein, the feasible and scalable synthesis of Fe
x
C@NC with 3D honeycomb-like carbon architecture and abundant Fe vacancies via template etching is reported. Such structure enable outstanding lithium-ion storage properties owing to hierarchical pores, improved intrinsic electrochemical activity, as well as the introduction of more active sites. As a result, the Fe
x
C@NC-2 presents a high reversible specific capacity of 1079 mAh g−1 after 1000 cycles. Moreover, an excellent cycling stability can be achieved via maintaining a high-capacity retention (689 mAh g−1, 98.4%) over 1000 cycles at 5 A g−1. This study provides a feasible strategy for developing high-performance hybrids with hierarchical pore and rich defects structures.
Time-varying magnetic field induced electric field across a current-transporting type-II superconducting loop: beyond dynamic resistance effect
Authors: Geng Jianzhao , Brooks Justin M , Bumby Chris W , Badcock Rodney A
Published: December 2021

The emergence of a potential drop across a current-transporting type-II superconducting loop under a perpendicular oscillating magnetic field is revealed. We have derived analytical formulae to describe the effect under DC transport current in 1D, based on Bean’s critical state model. The analytical formulae are verified by a finite element model. To exploit this effect, we have developed a transformer-like ‘resistive switch’, and experimentally observed a switching effect. This work demonstrates a physically important general insight of the interaction between DC transport currents and time-varying magnetic fields in type-II superconducting loops, which extends beyond the well-known ‘dynamic resistance’ effect. It also provides a useful view on the interaction between a ‘transport-current’ and a ‘screening-current’ in the superconductor. The resulting demonstrated switch has the potential to be used in a variety of applications including superconducting rectifiers, fault current limiters, and superconducting magnetic energy storages.
Seebeck effect studies in the charge density wave state of organic conductor α-(BEDT–TTF)2KHg(SCN)4
Authors: Krstovska D , Choi E S , Steven E
Published: December 2021

Angular, magnetic field and temperature dependence of the interlayer Seebeck effect of the multiband organic conductor

α
−

(
BEDT
−
TTF
)

2

KHg

(
SCN
)

4

is experimentally studied at temperatures down to 0.55 K and fields up to 31 T in a wide range of angles. The background magnetic field and angular component of the Seebeck effect as well as the magnetic quantum oscillations that originate from the closed Fermi surface orbits are analyzed. The background interlayer Seebeck effect components show that above certain tilt angle of the magnetic field and above the kink field there is another CDW state in

α
−

(
BEDT
−
TTF
)

2

KHg

(
SCN
)

4

, between previously known CDW0 and CDW
x
states, in agreement with magnetoresistance and magnetization studies in this material. Our observations show that this state possesses some of the properties of the CDW0 state. The Fermi surface in the third CDW state is still reconstructed but less imperfectly nested as expected as this state develops above the kink field. The temperature dependence of the interlayer Seebeck effect reveals that this state is developed at temperatures below 3 K and at field orientations around the second AMRO maximum. In addition, for the first time, a detailed T − θ phase diagram of

α
−

(
BEDT
−
TTF
)

2

KHg

(
SCN
)

4

based purely on Seebeck effect measurements is presented. We find that other states and transitions, beside the CDW states, also exist in a given temperature and angular range that have not been previously reported. These observations change the whole picture about the transport processes in the organic conductor

α
−

(
BEDT
−
TTF
)

2

KHg

(
SCN
)

4

and allow to better understand the complex nature of the CDW order in this and similar compounds.
LD-pumped high-power continuous-wave Pr3+:YLF deep red lasers at 718.5 and 720.8 nm
Authors: Liu Xiangrui , Li Zhuang , Shi Chengkun , Xiao Bo , Fang Run , Xue Yuchen , Feng Qichen , Lin Xiuji , Zhu Yao , Xu Guozhen , Xu Huiying , Cai Zhiping
Published: December 2021

We demonstrated 22 W LD-pumped high-power continuous-wave (CW) deep red laser operations at 718.5 and 720.8 nm based on an a-cut Pr3+:YLF crystal. The output power of both polarized directions reached the watt-level without output power saturation. A single wavelength laser operated at 720.8 nm in the π-polarized direction was achieved, with a high output power of 4.5 W and high slope efficiency of approximately 41.5%. To the best of our knowledge, under LD-pumped conditions, the laser output power and slope efficiency are the highest at 721 nm. By using a compact optical glass plate as an intracavity etalon, we suppressed the π-polarized 720.8 nm laser emission. And σ-polarized single-wavelength laser emission at 718.5 nm was achieved, with a maximum output power of 1.45 W and a slope efficiency of approximately 17.8%. This is the first time that we have achieved the σ-polarized laser emission at 718.5 nm generated by Pr3+:YLF lasers.
Neutron capture cross section of 169Tm measured at the CSNS Back-n facility in the energy region from 30 to 300 keV *
Authors: Ren Jie , Ruan Xichao , Jiang Wei , Bao Jie , Wang Jincheng , Zhang Qiwei , Luan Guangyuan , Huang Hanxiong , Nie Yangbo , Ge Zhigang , An Qi , Bai Huaiyong , Bao Yu , Cao Ping , Chen Haolei , Chen Qiping , Chen Yonghao , Chen Yukai , Chen Zhen , Cui Zengqi , Fan Ruirui , Feng Changqing , Gao Keqing , Gu Minhao , Han Changcai , Han Zijie , He Guozhu , He Yongcheng , Hong Yang , Huang Weiling , Huang Xiru , Ji Xiaolu , Ji Xuyang , Jiang Haoyu , Jiang Zhijie , Jing Hantao , Kang Ling , Kang Mingtao , Li Bo , Li Chao , Li Jiawen , Li Lun , Li Qiang , Li Xiao , Li Yang , Liu Rong , Liu Shubin , Liu Xingyan , Mu Qili , Ning Changjun , Qi Binbin , Ren Zhizhou , Song Yingpeng , Song Zhaohui , Sun Hong , Sun Kang , Sun Xiaoyang , Sun Zhijia , Tan Zhixin , Tang Hongqing , Tang Jingyu , Tang Xinyi , Tian Binbin , Wang Lijiao , Wang Pengcheng , Wang Qi , Wang Taofeng , Wang Zhaohui , Wen Jie , Wen Zhongwei , Wu Qingbiao , Wu Xiaoguang , Wu Xuan , Xie Likun , Yang Yiwei , Yi Han , Yu Li , Yu Tao , Yu Yongji , Zhang Guohui , Zhang Linhao , Zhang Xianpeng , Zhang Yuliang , Zhang Zhiyong , Zhao Yubin , Zhou Luping , Zhou Zuying , Zhu Danyang , Zhu Kejun , Zhu Peng , (The CSNS Back-n Collaboration)
Published: December 2021

The capture cross sections of the 169Tm

reaction were measured at the back streaming white neutron beam line (Back-n) of the China Spallation Neutron Source (CSNS) using four C6D6 liquid scintillation detectors. The background subtraction, normalization, and correction were carefully considered in the data analysis to obtain accurate cross sections. For the resonance at 3.9 eV, the R-matrix code SAMMY was used to determine the resonance parameters with the internal normalization method. The average capture cross sections of 169Tm for energy between 30 and 300 keV were extracted relative to the 197Au

reaction. The measured cross sections of the 169Tm

reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4% – 7.0% in this study and described in terms of average resonance parameters using a Hauser-Feshbach calculation with fluctuations. The point-wise cross sections and the average resonance parameters showed fair agreement with the evaluated values of the ENDF/B-VIII.0 library in the energy region studied.
The optical system of the Tenerife Microwave Spectrometer: a window for observing the 10–20 GHz sky spectra
Authors: Alonso-Arias P. , Fuerte-Rodríguez P.A. , Hoyland R.J. , Rubiño-Martín J.A.
Published: December 2021

The TMS optical system is based on a decentered
dual-reflector system in a Gregorian configuration to observe with
an angular resolution of less than 2°. The primary goal
of the present study is to evaluate the final design and verify that
it satisfies the design requirements. We aim for low
cross-polarization (-30 dB), low sidelobe (-25 dB) levels, and a
stable beam in terms of shape (low ellipticity) and size over a full
octave bandwidth (10–20 GHz). We performed both ray-tracing and
full-wave simulations using the CST Studio software in order to
investigate the system behaviour. We gave special attention to the
beam frequency variation and polarization leakage. We have
characterized the effects on the radiation pattern produced by the
cryostat window. We present the final design of the TMS optical
system, as well as a complete study of the system's performance in
terms of cross-polarization, sidelobes, ellipticity and
beamwidth. We discuss the effects of sidelobes and study the need
for a baffle.
Measurements and analysis of different front-end configurations for monolithic SiGe BiCMOS pixel detectors for HEP applications
Authors: Martinelli F. , Magliocca C. , Cardella R. , Charbon E. , Iacobucci G. , Nessi M. , Paolozzi L. , Rücker H. , Valerio P.
Published: December 2021

This paper presents a small-area monolithic pixel detector
ASIC designed in 130 nm SiGe BiCMOS technology for the upgrade of
the pre-shower detector of the FASER experiment at CERN. The purpose
of this prototype is to study the integration of fast front-end
electronics inside the sensitive area of the pixels and to identify
the configuration that could satisfy at best the specifications of
the experiment. Self-induced noise, instabilities and cross-talk
were minimised to cope with the several challenges associated to the
integration of pre-amplifiers and discriminators inside the pixels.
The methodology used in the characterisation and the design choices
will also be described. Two of the variants studied here will be
implemented in the pre-production ASIC of the FASER experiment
pre-shower for further tests.
High-accuracy absolute magnetometry with application to the Fermilab Muon g-2 experiment
Authors: Flay D. , Kawall D. , Chupp T. , Corrodi S. , Farooq M. , Fertl M. , George J. , Grange J. , Hong R. , Osofsky R. , Ramachandran S. , Swanson E. , Winter P.
Published: December 2021

We present details of a high-accuracy absolute scalar magnetometer
based on pulsed proton NMR. The B-field magnitude is determined
from the precession frequency of proton spins in a cylindrical
sample of water after accounting for field perturbations from
probe materials, sample shape, and other corrections. Features of the design,
testing procedures, and corrections necessary for qualification
as an absolute scalar magnetometer are described. The device was
tested at B = 1.45 T but can be modified for a range exceeding
1–3 T. The magnetometer was used to calibrate other NMR magnetometers
and measure absolute magnetic field magnitudes to an accuracy
of 19 parts per billion as part of a measurement of the muon
magnetic moment anomaly at Fermilab.
The effect of MV image spatial resolution on the patient positioning and patient specific QA
Authors: Dudas D. , Koniarova I. , Prusa P. , Koncek O. , Osmancikova P. , Semmler M.
Published: December 2021

Electronic portal imaging device (EPID) is a common part of
almost each radiotherapy treatment unit. It is a quick and simple
tool for various clinical procedures, e.g. verification of patient
positioning or patient specific QA. Currently available EPIDs have
usually the spatial resolution below 0.5 mm. As EPIDs are not
primarily designed for diagnostics, even lower spatial resolution
might be acceptable. This work assesses the effect of MV image
spatial resolution on clinical routines which employ the EPID and
addresses the minimal technical requirements of such devices. The
aim is to determine if EPIDs with poorer spatial resolution are able
to reach the same clinical quality as currently used EPIDs. The
effects of MV image spatial resolution on the imaging performance,
patient positioning and patient specific QA were studied. The lower
spatial resolution was simulated by manually downsampling the
original images down to 4× poorer spatial resolution. The
study includes an analysis of 96 images used for the patient
positioning verification and 61 treatment field images used for the
patient specific QA.
Digital holographic camera with extended stochastic illumination for non-destructive inspection of silicon optics
Authors: Dwivedi Gaurav , Pensia Lavlesh , Debnath Sanjit K , Kumar Raj
Published: December 2021

In the present work, we propose a compact digital holographic camera (DHC) with extended stochastic illumination for full-field non-destructive inspection of silicon optics fabricated in a computerized numerical control machine. The developed technique overcomes the limitation of digital holography imparted by the finite size of the active area of the recording sensor that can image a specular surface. The original aspect of this research work is to develop a system that enables reconstruction and testing of a specular surface. For this a dual diffuser configuration is incorporated in a compact DHC developed for non-destructive testing (NDT) applications. The generation of a stochastic illumination beam using the diffusers is explained by simulating the propagation of a light beam through a random phase function of the scattering medium. The stochastic optical field produced by the combination of diffusers in the DHC makes the camera suitable for NDT of the specular surface of silicon optics. The effects of the number of diffusers and their relative positions on the imaging area of the specular object are studied for development of an optimized configuration of DHC. Applicability of the proposed scheme is demonstrated through detection of defects in silicon optics using digital holographic interferometry.
Wave–particle duality quantified for the first time
Authors: Padavic-Callaghan Karmela
Published: December 2021

Scientists in South Korea have used a precisely controlled photon source to measure a photon’s degree of “waveness” and “particle-ness”.
Evolution of spins looks surprisingly classical
Authors: Ball Philip
Published: December 2021

Researchers have shown that the development of a many-particle system of quantum spins can look surprisingly like the classical process of diffusion.
Tibet seen as ideal stargazing spot
Authors: Xin Ling
Published: December 2021

Chinese astronomers think that a location on Saishiteng Mountain in the Tibetan Plateau rivals existing astronomy meccas and could be home to next-generation observatories. Ling Xin reports.
Climate matters
Authors: Durrani Matin
Published: December 2021

As the COP26 climate summit nears, how are physicists addressing the climate crisis?
Lost in translation
Authors: Baetke Frank
Published: December 2021

In response to Pruthvi Mehta’s Forum article “Bridging the language divide” in which she discusses the predominance of the English language in the scientific community, and the difficulties this causes for scientists who are non-native English speakers.
Maths in a muddle
Authors: Reynolds Martin
Published: December 2021

In response to Niki Bell’s Forum article “Where did all the calculus go?” in which she discusses the A-level curricula for maths and physics, and how they could be restructured to help students develop the essential maths skills for studying physics at a higher level.
The missing mass
Authors: Atkins Chris
Published: December 2021

In response to the Lateral Thoughts quiz “Sporting chance”, in which question 8 asked for a rough estimate of the theoretical maximum height a pole vaulter could jump, and why the actual world record is slightly above this.
Qubits for the future
Authors: Hiscott Laura
Published: December 2021

Laura Hiscott reviews Quantum Technology | Our Sustainable Future by “The Quantum Daily”.
NASA engulfed in JWST renaming row
Authors: Banks Michael
Published: December 2021

A member of NASA’s Astrophysics Advisory Committee has resigned over the agency’s handling of an investigation into whether the James Webb Space Telescope (JWST) should be renamed.
Nobel-winning astronomer Antony Hewish dies aged 97
Authors: Banks Michael
Published: December 2021

The British Nobel-prize-winning astronomer Antony Hewish has died on 13 September at the age of 97.
Illuminating dark matter
Authors: Chapman Emma
Published: December 2021

Emma Chapman reviews Bright Galaxies, Dark Matter, and Beyond: the Life of Astronomer Vera Rubin by Ashley Jean Yeager.
Ask me anything: Ciara Muldoon
Authors: Hiscott Laura
Published: December 2021

Based in Exeter, UK, Ciara Muldoon holds a BSc in experimental physics from the National University of Ireland, Galway, and a PhD in science studies from the University of Bath. After working as a science-communication consultant, she became an Internet entrepreneur with her husband, Neil Williams, a former aerospace engineer. Their latest project is a charitable search engine that helps tackle climate change and climate injustice.
Cooper pairs spotted above critical temperature for superconductivity
Authors: Wogan Tim
Published: December 2021

Researchers have detected Cooper pairs above the critical temperature in a superconductor despite it not having a pseudogap.
Leap for quantum advantage in optical and superconducting systems
Authors: Johnston Hamish
Published: December 2021

Two different quantum computers – one using light and the other using superconducting circuits – have performed calculations beyond the capability of conventional computers.
Fusion firms target electricity generation by the 2030s
Authors: Banks Michael
Published: December 2021

Most private fusion companies expect fusion power to be supplying electricity to the grid in the 2030s, according to an industry report.
Call for ‘great observatory’ to succeed Hubble
Authors: Banks Michael
Published: December 2021

Michael Banks reveals the highlights of the long-awaited Astro2020 Decadal Survey, which will define the course of astronomy and astrophysics in the US and beyond over the next 10 years.
Ethics in the quantum age
Authors: Kop Mauritz
Published: December 2021

Mauritz Kop assesses the ethical principles we must all adopt so that the application of quantum technologies is equitable and safe.
Quantum conundrum
Authors: Crease Robert P
Published: December 2021

While the technological applications of quantum mechanics are bright, its meaning remains opaque. Thankfully, as Robert P Crease explains, philosophers of science are working on it.
Setting the scene for a quantum marketplace
Authors: Ball Philip
Published: December 2021

As quantum computing makes its first forays from the lab to the real world, are the latest claims mere hype causing a bubble that will burst before the field finds its feet? Or are investors and researchers right to be enthusiastic about this burgeoning technological revolution? Philip Ball investigates the successes and pitfalls of commercializing quantum information technology.
The key to our quantum future
Authors: Commissariat Tushna
Published: December 2021

Safeguarding our communications data and infrastructures will become a much harder task in a quantum-enabled future. KETS Quantum Security chief executive Chris Erven talks to Tushna Commissariat about how integrating quantum-based systems into existing communication is key.
Brilliant polymath, troubled person
Authors: Robinson Andrew
Published: December 2021

Andrew Robinson reviews The Man from the Future: the Visionary Life of John von Neumann by Ananyo Bhattacharya.
Winter wonder worlds
Authors: Spring Eleanor
Published: December 2021

The winter holiday season comes but once a year – on Earth. Eleanor Spring takes a tour through some of the seasonal extremities experienced on distant worlds. A chilly Earth winter never looked so inviting!
Paper-based triboelectric nanogenerator and activities of salt ions
Authors: Palsaniya Shatrudhan , Nehra Komal , Dasmahapatra Ashok Kumar
Published: December 2021

This work presents a triboelectric nanogenerator (TENG) fabrication using polytetrafluoroethylene, aluminum foil, and cellulose paper. Mechanical interactions lead to atomic defects that stimuli the delocalized electrostatic charge carriers and kinetic energy. The addition of ionic salt’s microdroplets improved the TENG’s performance. Eventually, surface charge activities have escalated the electrical signals. Further, studied spontaneously increased charge transport performance at the steady-state condition in the presence of NaCl ionic droplets. We considered that these ionic activities actively participated in detecting salt ions.
Dimension investigation to pneumatic network bending soft actuators for soft robotic applications
Authors: Salem Mohamed E M , Wang Qiang
Published: December 2021

Soft actuators have been investigated for robots that interact with people, such as industrial robots, entertainment robots, and medical robots. Although soft actuators have been utilised in several applications, design tools that can assist in the effective and systematic design of actuators are needed. This paper focused on the most common soft actuators for bending motion, the Pneumatic Networks bending actuators. Paper presented a survey on the effects of changing the dimensions on the soft actuator and its cross-section shape on the soft actuator flexibility and the forces generated at different applied pressures. This survey can be used to optimize the dimension ratio for the soft actuator and the cross-section shape. Furthermore, this paper analyzed the possible reasons for the dimension change effect. The performance of the bending soft actuator was evaluated using ABAQUS/CAE software simulation models to provide quantitative insights into the actuators’ behaviours. Thus, this paper provided a lot of insights that can be used to guide and accelerate the soft actuator design process to create strong and flexible Pneumatic Networks bending actuators. Using the paper insights outputs, a soft gripper was designed that can grasp many complex objects without needing any modification in the gripper shape. To show the proposed actuators’ capacity to do complicated movements and expand their applications, a completely soft hand was created that can mimic the mobility of the human hand as nearly as possible, and this ability was verified using hand sign language settings.
Isoperimetric inequality in noncompact 𝖬𝖢𝖯 spaces
Authors: Cavalletti Fabio , Manini Davide
Published: December 2021

We prove a sharp isoperimetric inequality for the class of metric measure spaces verifying the synthetic Ricci curvature lower bounds Measure Contraction property (

M
C
P

(
0
,
N
)

\mathsf {MCP}(0,N)

) and having Euclidean volume growth at infinity. We avoid the classical use of the Brunn-Minkowski inequality, not available for

M
C
P

(
0
,
N
)

\mathsf {MCP}(0,N)

, and of the PDE approach, not available in the singular setting. Our approach will be carried over by using a scaling limit of localization.
Essentiality of Sis1, a J-domain protein Hsp70 cochaperone, can be overcome by Tti1, a specialized PIKK chaperone
Authors: Schilke Brenda A. , Craig Elizabeth A.
Published: December 2021

Why Sis1 is the only essential J-domain protein cochaperone of the yeast cytosol/nucleus is unknown. We isolated suppressors having substitutions in Tti1, a component of the TTT complex, which is a specialized chaperone system for PIKK proteins, suggesting that Sis1 is required as an Hsp70 cochaperone for PIKK folding/maintenance.
Systemic L-ornithine supplementation specifically increases ovarian putrescine levels during ovulation in mice
Authors: Lavergne Christopher L J , Tao Yong , Ren Yanping , Lafleur Nahantara , Liu X Johné
Published: December 2021

In all mammalian species examined thus far, the ovaries produce a burst of ornithine decarboxylase (ODC) and putrescine during ovulation or after application of human chorionic gonadotropin (hCG). Aged mice have significantly reduced levels of this periovulatory ODC and putrescine rise. Putrescine supplementation, in vitro during oocyte maturation or in mouse drinking water during the periovulatory period, reduces egg aneuploidies and embryo resorption, improving fertility of aged mice. These studies suggest that periovulatory putrescine supplementation may be a simple and effective therapy for reproductive aging for women. However, putrescine supplementation is expected to increase widespread tissue putrescine levels, raising concerns of nonspecific and unwanted side effects. Given that ODC is highly expressed in the ovaries during ovulation but otherwise exhibits low activity in most tissues, we hypothesized that periovulatory supplementation of L-ornithine, the substrate of ODC, might be suitable for delivering putrescine specifically to the ovaries. In this study, we have demonstrated that systemic application of L-ornithine via oral gavage or subcutaneous injection increased ovarian putrescine levels; the increase was restricted to animals that had been injected with hCG. Furthermore, L-ornithine specifically increased ovarian putrescine levels without affecting putrescine levels in any other tissues. However, our attempts to improve fertility of aged mice through L-ornithine supplementation in mouse drinking water produced either no effects (1% L-ornithine) or negative impact on fertility (4% ornithine). Our results suggest that it might not be feasible to achieve fertility-enhancing ovarian putrescine levels via L-ornithine supplementation in drinking water without encountering undesired consequences of high dose of exogenous L-ornithine.
Amphetamine-induced dopamine release and impulsivity in Parkinson’s disease
Authors: Song Alexander K , Hay Kaitlyn R , Trujillo Paula , Aumann Megan , Stark Adam J. , Yan Yan , Kang Hakmook , Donahue Manus J , Zald David H , Claassen Daniel O
Published: December 2021

Impulsive-compulsive behaviours manifest in a substantial proportion of subjects with Parkinson’s disease. Reduced ventral striatum dopamine receptor availability, and increased dopamine release is noted in patients with these symptoms. Prior studies of impulsivity suggest that midbrain D2 autoreceptors regulate striatal dopamine release in a feedback inhibitory manner, and in healthy populations, greater impulsivity is linked to poor proficiency of this inhibition. This has not been assessed in a Parkinson’s disease population. Here, we applied 18F-fallypride PET studies to assess striatal and extrastriatal D2-like receptor uptake in a placebo-controlled oral dextroamphetamine sequence. We hypothesized that Parkinson’s disease patients with impulsive-compulsive behaviours would have greater ventral striatal dopaminergic response to dextroamphetamine, and that an inability to attenuate ventral striatal dopamine release via midbrain D2 autoreceptors would underlie this response.

Twenty patients with Parkinson’s disease (mean age = 64.1 ± 5.8 years) both with (n = 10) and without (n = 10) impulsive-compulsive behaviours, participated in a single-blind dextroamphetamine challenge (oral; 0.43 mg/kg) in an OFF dopamine state. All completed PET imaging with 18F-fallypride, a high-affinity D2-like receptor ligand, in the placebo and dextroamphetamine state.

Both voxelwise and region of interest analyses revealed dextroamphetamine-induced endogenous dopamine release localized to the ventral striatum, and the caudal-medial orbitofrontal cortex. The endogenous dopamine release observed in the ventral striatum correlated positively with patient-reported participation in reward-based behaviours, as quantified by the self-reported Questionnaire for Impulsivity in Parkinson’s disease Rating Scale. In participants without impulsive-compulsive behaviours, baseline midbrain D2 receptor availability negatively correlated with ventral striatal dopamine release; however, this relationship was absent in those with impulsive-compulsive behaviours. These findings emphasize that reward-based behaviours in Parkinson’s disease are regulated by ventral striatal dopamine release, and suggest that loss of inhibitory feedback from midbrain autoreceptors may underlie the manifestation of impulsive-compulsive behaviours.