bluuebunny/crossref_metadata_2025 huggingface dataset:
Extended depth-of-field light-sheet microscopy improves imaging of large volumes at high numerical aperture
Authors: Keomanee-Dizon Kevin , Jones Matt , Luu Peter , Fraser Scott E. , Truong Thai V.
Published: October 2022

Light-sheet microscopes must compromise among field of view, optical sectioning, resolution, and detection efficiency. High-numerical-aperture (NA) detection objective lenses provide higher resolution, but their narrow depth of field inefficiently captures the fluorescence signal generated throughout the thickness of the illumination light sheet when imaging large volumes. Here, we present ExD-SPIM (extended depth-of-field selective-plane illumination microscopy), an improved light-sheet microscopy strategy that solves this limitation by extending the depth of field (DOF) of high-NA detection objectives to match the thickness of the illumination light sheet. This extension of the DOF uses a phase mask to axially stretch the point-spread function of the objective lens while largely preserving lateral resolution. This matching of the detection DOF to the illumination-sheet thickness increases the total fluorescence collection, reduces the background, and improves the overall signal-to-noise ratio (SNR), as shown by numerical simulations, imaging of bead phantoms, and imaging living animals. In comparison to conventional light sheet imaging with low-NA detection that yields equivalent DOF, the results show that ExD-SPIM increases the SNR by more than threefold and dramatically reduces the rate of photobleaching. Compared to conventional high-NA detection, ExD-SPIM improves the signal sensitivity and volumetric coverage of whole-brain activity imaging, increasing the number of detected neurons by over a third.
Adaptive Capon beamforming for lensless electron cyclotron emission imaging with high spatial resolution
Authors: Idei H. , Fukuyama M. , Sakai S. , Mishra K. , Nishimura K. , Ikezoe R. , Onchi T. , Ido T. , Hanada K.
Published: October 2022

Electron cyclotron emission (ECE) imaging diagnostics incorporating a lensless approach have been developed for measurements involving active spatial selectivity and direction-of-arrival estimation. The Capon method for adaptive-array analysis was proposed to improve the spatial resolution of the two-dimensional ECE imaging technique. Broadband noise source emissions were used to simulate the ECE to verify the practical effectiveness of the Capon method in the ECE imaging. Multiple noise source emission positions were properly estimated with a high spatial resolution using the Capon method.
Self-heating in ultra-wide bandgap n-type SrSnO3 thin films
Authors: Golani Prafful , Saha Chinmoy Nath , Sundaram Prakash P. , Liu Fengdeng , Truttmann Tristan K. , Chaganti V. R. Saran Kumar , Jalan Bharat , Singisetti Uttam , Koester Steven J.
Published: October 2022

This work reports the quantification of rise in channel temperature due to self-heating in two-terminal SrSnO3 thin film devices under electrical bias. Using pulsed current–voltage (I–V) measurements, thermal resistances of the thin films were determined by extracting the relationship between the channel temperature and the dissipated power. For a 26-nm-thick n-doped SrSnO3 channel with an area of 200 μm2, a thermal resistance of 260.1 ± 24.5 K mm/W was obtained. For a modest dissipated power of 0.5 W/mm, the channel temperature rose to ∼176 °C, a value which increases further at higher power levels. Electro-thermal simulations were performed which showed close agreement between the simulated and experimental I–V characteristics both in the absence and presence of self-heating. The work presented is critical for the development of perovskite-based high-power electronic devices.
Cracking behavior in lead zirconate titanate films with different Zr/Ti ratios
Authors: Cheng Christopher , Peters Travis , Trolier-McKinstry Susan
Published: October 2022

Crack initiation stresses for different lead zirconate titanate (PZT) film compositions were investigated. PZT/Pt/TiO2/SiO2/Si stacks with 2.0 μm thick {100} oriented PZT films at the morphotropic phase boundary (MPB) showed a characteristic strength of 1137 MPa, and the film thickness served as the limiting flaw size for failure of the film/substrate stack. In contrast, for Zr/Ti ratios of 40/60 and 30/70, the characteristic stack strength increased while the Weibull modulus decreased to values typical for that of Si. This difference is believed to be due to toughening from ferroelasticity or phase switching. X-ray diffraction showed that the volume fraction of c-domains increased in Ti-rich compositions. This would allow for more switching from c to a-domains under biaxial tensile stress. Zr/Ti concentration gradients were present for all compositions, which contributed to the observation of a rhombohedral phase off the MPB. Due to the reduced tendency toward cracking, off-MPB compositions are potentially of interest in actuators, albeit with the trade-off of needing a high actuation voltage.
Charge transfer dynamics and interlayer exciton formation in MoS2/VOPc mixed dimensional heterojunction
Authors: Schwinn Madison C. , Rather Shahnawaz R. , Lee Changmin , Bland Matthew P. , Song Thomas W. , Sangwan Vinod K. , Hersam Mark C. , Chen Lin X.
Published: October 2022

Mixed-dimensional van der Waals heterojunctions involve interfacing materials with different dimensionalities, such as a 2D transition metal dichalcogenide and a 0D organic semiconductor. These heterojunctions have shown unique interfacial properties not found in either individual component. Here, we use femtosecond transient absorption to reveal photoinduced charge transfer and interlayer exciton formation in a mixed-dimensional type-II heterojunction between monolayer MoS2 and vanadyl phthalocyanine (VOPc). Selective excitation of the MoS2 exciton leads to hole transfer from the MoS2 valence band to VOPc highest occupied molecular orbit in ∼710 fs. On the contrary, selective photoexcitation of the VOPc layer leads to instantaneous electron transfer from its excited state to the conduction band of MoS2 in less than 100 fs. This light-initiated ultrafast separation of electrons and holes across the heterojunction interface leads to the formation of an interlayer exciton. These interlayer excitons formed across the interface lead to longer-lived charge-separated states of up to 2.5 ns, longer than in each individual layer of this heterojunction. Thus, the longer charge-separated state along with ultrafast charge transfer times provide promising results for photovoltaic and optoelectronic device applications.
Flows of ionizing gas in the plasma accelerator channel with longitudinal magnetic field
Authors: Kozlov Andrei N.
Published: October 2022

Model and results of numerical experiments are presented for axisymmetric flows of ionizing gas in the presence of an additional longitudinal magnetic field in the channel of quasi-stationary plasma accelerator considered as perspective electric propulsion plasma engine. A two-dimensional flow model for a three-component medium consisting of atoms, ions, and electrons is based on magnetogasdynamic equations written in terms of the vector potential of magnetic field, taking into account electrical conductivity, thermal conductivity, and radiation transfer. A three-dimensional model of radiative transfer includes main mechanisms of emission and absorption for different parts of the spectrum. Numerical studies of the ionization process and radiation transfer were carried out in an approximation of local thermodynamic equilibrium. The stabilizing effect of flow rotation in the presence of a longitudinal magnetic field and thermal conductivity along the magnetic field on non-stationary unstable flows of ionizing gas, which arise at low discharge currents, is considered.
Aqueous-solution-synthesized gallium oxide dielectrics for high-mobility thin-film transistors enhanced by phosphorus incorporation
Authors: Xu Wangying , Peng Tao , Chen Lin , Huang Weicheng , Zhuo Shuangmu , Lin Qiubao , Zhao Chun , Xu Fang , Zhang Yu , Zhu Deliang
Published: October 2022

Gallium oxide (Ga2O3) is widely used as an ultra-wide bandgap semiconductor in emerging optoelectronics. Recent works show that Ga2O3 could be a promising high-κ dielectric material due to its high thermal stability, excellent moisture resistance, and ease of processing from solution phase. However, the dielectric properties of pristine Ga2O3 could be further improved. Here, aqueous-solution-synthesized Ga2O3 with excellent dielectric properties are achieved by phosphorus (P) incorporation. Using an Ga2O3 dielectric with optimal P (20 at. %) incorporation, oxide thin-film transistors (TFTs) exhibit enhanced performance with a mobility of 20.49 ± 0.32 cm2 V−1 s−1, subthreshold swing of 0.15 ± 0.01 V/dec, current on/off ratio >106, and superior bias stress stability. Systematic analyses show that proper P incorporation considerably reduces oxygen-related defects (oxygen vacancies and hydroxyls) in Ga2O3, resulting in better dielectric and TFT performance.
Model-free prediction of multistability using echo state network
Authors: Roy Mousumi , Mandal Swarnendu , Hens Chittaranjan , Prasad Awadhesh , Kuznetsov N. V. , Dev Shrimali Manish
Published: October 2022

In the field of complex dynamics, multistable attractors have been gaining significant attention due to their unpredictability in occurrence and extreme sensitivity to initial conditions. Co-existing attractors are abundant in diverse systems ranging from climate to finance and ecological to social systems. In this article, we investigate a data-driven approach to infer different dynamics of a multistable system using an echo state network. We start with a parameter-aware reservoir and predict diverse dynamics for different parameter values. Interestingly, a machine is able to reproduce the dynamics almost perfectly even at distant parameters, which lie considerably far from the parameter values related to the training dynamics. In continuation, we can predict whole bifurcation diagram significant accuracy as well. We extend this study for exploring various dynamics of multistable attractors at an unknown parameter value. While we train the machine with the dynamics of only one attractor at parameter p, it can capture the dynamics of a co-existing attractor at a new parameter value p+Δp. Continuing the simulation for a multiple set of initial conditions, we can identify the basins for different attractors. We generalize the results by applying the scheme on two distinct multistable systems.
Neural-network-based Riemann solver for real fluids and high explosives; application to computational fluid dynamics
Authors: Ruggeri Matteo , Roy Indradip , Mueterthies Michael J. , Gruenwald Tom , Scalo Carlo
Published: October 2022

The Riemann problem is fundamental to most computational fluid dynamics (CFD) codes for simulating compressible flows. The time to obtain the exact solution to this problem for real fluids is high because of the complexity of the fluid model, which includes the equation of state; as a result, approximate Riemann solvers are used in lieu of the exact ones, even for ideal gases. We used fully connected feedforward neural networks to find the solution to the Riemann problem for calorically imperfect gases, supercritical fluids, and high explosives and then embedded these network into a one-dimensional finite volume CFD code. We showed that for real fluids, the neural networks can be more than five orders of magnitude faster than the exact solver, with prediction errors below 0.8%. The same neural networks embedded in a CFD code yields very good agreement with the overall exact solution, with a speed-up of three orders of magnitude with respect to the same CFD code that use the exact Riemann solver to resolve the flux at the interfaces. Compared to the Rusanov flux reconstruction method, the neural network is half as fast but yields a higher accuracy and is able to converge to the exact solution with a coarser grid.
Clinician perspectives on rapid transition to telehealth during COVID-19 in Australia – a qualitative study
Authors: Smyth Lillian , Roushdy Suzannah , Jeyasingham Jerusha , Whitbread Joshua , O’Brien Peta , Lloyd Charles , Lueck Christian J. , Hawkins Carolyn A. , Reynolds Graham , Perriman Diana
Published: October 2022

Objective The coronavirus disease 2019 (COVID-19) pandemic precipitated a major shift in the use of telehealth in Australia. The changes highlighted gaps in our knowledge regarding the efficacy of, and clinician attitudes to, the use of telehealth. The current study expands and deepens the available evidence as a result of being collected in unique circumstances that removed one of the major barriers (lack of Medicare rebates) and also one major enablers (willingness) of telehealth uptake. Methods Using a semi-structured interview, we invited clinicians (N = 39) to share their perspectives, attitudes and experiences of using telehealth. Topics covered included perceptions of the strengths and challenges of telehealth, and how experience of using telehealth during the COVID-19 pandemic had influenced clinicians’ views and intentions regarding their future practice. Participants included clinicians from five disciplines across public and private practice: paediatrics, neurology, immunology, rural general practice, and orthopaedics. Results We found three key dimensions for consideration when assessing the suitability of telehealth for ongoing practice: the attributes of the patient population, the attributes of the clinical context and environment, and the risks and benefits of a telehealth approach. These findings map to the existing literature and allow us to infer that the experiences of clinicians who previously would have chosen telehealth did not differ significantly from those of our ‘pandemic-conscripted’ clinicians. Conclusions Our findings map clearly to the existing literature and allow us to infer that the experiences of the clinicians who have chosen telehealth (and are already represented in the literature) did not differ significantly from those trying out telehealth under the unique circumstances of the removal of the Medicare Benefits Scheme barrier and external pressure that over-rides the ‘willingness’ enabling factor in uptake decisions.
What factors affect species richness and distribution dynamics within two Afromontane protected areas?
Authors: Uzabaho Eustrate , Kayijamahe Charles Birasa , Musana Abel , Uwingeli Prosper , Masaba Christopher , Nyiratuza Madeleine , Moore Jennifer Frances
Published: October 2022

Context Biodiversity monitoring programs provide information on the status and trends in wildlife populations. These trends are unknown for most mammals within African montane forests, which harbour many endemic and threatened species. Camera traps are useful for assessing mammal populations, because they allow for the estimation of species richness, occupancy, and activity patterns. Aims We sought to explore the richness and distribution of small- to large-sized mammals by using occupancy models while accounting for imperfect detection in Volcanoes and Mgahinga Gorilla National Parks, in Rwanda and Uganda. Methods We used camera-trap data collected from 2014 to 2017 by the Tropical Ecology Assessment and Monitoring (TEAM) network and multi-season occupancy models with multispecies data to assess the dynamics of species richness and distribution in the Virunga Massif and the influence of site covariates on species detection probability, occupancy, colonisation and extinction. Key results We identified 17 species from 7047 trap-days, with most of them showing an uneven distributional pattern throughout the park. We found that average species richness per site increased from five to seven species in 2017. Average local colonisation was estimated at 0.13 (s.e. 0.014), but the probability of local extinction was 0.17 (s.e. 0.028) and negatively influenced by distance from the park boundary. Detection probability was highest for medium-sized species. For species distribution, we found that black-fronted duiker, Cephalophus nigrifrons, and bushbuck, Tragelaphus scriptus, declined in distribution but remained widespread in our study area, while all other species showed an increase in distribution over the study period. Conclusions Our approach allowed us to draw inferences on rare species, such as African golden cat, Caracal aurata, by estimating detection probability on the basis of shared covariate information with more common, widespread species. As such, we were able to estimate all occupancy parameters across the terrestrial mammal community. Implications The results of this study on the distribution of terrestrial mammal species can be used by park management to inform optimal ranger patrolling efforts for mitigating threats in areas of high species presence. Additionally, the results can highlight locations of potential human–wildlife conflicts on the basis of species commonly found along the park boundary.
Update of the BIPM comparison BIPM.RI(II)-K1.Ba-133 of activity measurements of the radionuclide 133Ba to include the 2016 result of the NRC (Canada), the 2018 result of the TENMAK-NÜKEN (Türkiye), the 2019 result of the NMISA (South Africa) and the 2019 result of the NIST (United States)
Authors: Michotte C , Courte S , Coulon R , Nonis M , Judge S , Laureano-Perez L , Fytzgerald R , Rooy M W van , Staden M J van , Lubbe J , Galea R , Moore K , Yeltepe E , Dirican A
Published: October 2022

Main text

Since 1977, 23 laboratories have submitted 45 samples of 133Ba to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ba-133. Recently, the NRC (Canada), the TENMAK-NÜKEN (Türkiye), the NMISA (South Africa) and the NIST (United States) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between the updated KCRV and each equivalent activity measured in the SIR or linked to the SIR from the APMP.RI(II)-K2.Ba-133 comparison have been calculated and the results are given in the form of a table. A graphical representation is also given.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Modeling of vibrational excitation dynamics in a nanosecond CO2 discharge
Authors: Naidis G V , Babaeva N Yu
Published: October 2022

The temporal dynamics of excitation of the asymmetric vibrational mode of CO2 molecules in a nanosecond discharge is simulated. The values of the electric field andthe number density of electrons versus time, calculated for a known experimental dependence of the discharge current on time, are used to evaluate the number densities of the first and second vibrational levels of the asymmetric mode. It is shown that the dynamics of the densities of these levels, calculated using generally accepted values of the vibrational excitation rate constants, is in reasonable agreement with experimental data.
Phase controllable FSR design and its application into a high-gain transmitarray antenna with a low radar cross-section
Authors: Zhang Zhiyun , Cao Xiangyu , Yang Huanhuan , Li Tong , Li Sijia , Ji Kefeng
Published: October 2022

In this study, a high-gain transmitarray antenna (TAA) is proposed to achieve a low radar cross-section (RCS) with polarization-insensitive characteristic. Initially, an anisotropic frequency selective rasorber (FSR) structure is constructed by a detailed analysis of the current distributions and parameter adjustments. Hence, manipulations of absorption and transmission are achieved, along with covering a transmission phase cycle by rotating the element at 90°. Then, employing a phase-controllable FSR and focal length optimization, a low-RCS and high-gain TAA is presented. For the radiation case, the proposed antenna has a pencil pattern with a peak gain of 21.8 dBi. The F/D ratio is low when a wide-beam feed is utilized. At scattering state, in-band and out-of-band 6 dB RCS reductions are realized ranging from 7.6 to 10.4 GHz and 11.6–12.4 GHz compared to the reference TA. Moreover, its bistatic RCS is reduced in approximately ±90° of angular space under normal incidence. The effectiveness of the proposed design is verified by experiments.
Two-dimensional axisymmetric radiation hydrodynamics model of moderate-intensity nanosecond laser-produced plasmas
Authors: Min Qi , Shen Ruizi , Su Maogen , Lu Haidong , He Siqi , Liu Xingbang , Li Yue , Tao Qianqian , Wu Yanhong , Sun Duixiong , Cao Shiquan , Dong Chenzhong
Published: October 2022

A two-dimensional axisymmetric radiation hydrodynamics model has been proposed to simulate nanosecond laser ablation of a solid target in ambient argon, air and helium at different pressures. The heat conduction equation used to simulate the conduction of laser deposition energy in the target and gas dynamic equations to describe the interaction between laser and vapor plasma and the evolution of plasma are coupled through the Knudsen layer relations at the target-vapor interface. A collisional-radiative model including 12 atomic processes is used to calculate the population of atomic energy levels and fractional ion abundance. The internal energy and pressure of the plasma are expressed by the equations of state based on a real gas approximation, which divides the internal energy into the ionization energy, thermal energy, and excitation energy of atoms and ions. The distributions of the temperature, pressure, density and velocity of the target and plasma are calculated by using this model, and the results are analyzed. Experimental results of multiple diagnostic tools including fast photography, shadowgraphy images, spatio-temporally resolved optical emission spectroscopy and laser interferometry, are used to benchmark the simulation results, and satisfactory consistencies are obtained. The model provides a numerical tool to interpret experimental data of a moderate-intensity nanosecond laser ablated solid target when the temperature of the target surface does not reach the critical value.
GaAs a model system to study the role of electron–phonon coupling on ionization stimulated damage recovery
Authors: Chakravorty Anusmita , Dufour Ch , Mishra Ambuj , Kanjilal D , Kabiraj Debdulal
Published: October 2022

The latent ion tracks observed in various materials after swift heavy ion (SHI) irradiation is often explained in the framework of thermal spike model (TSM). Dominantly, SHIs deposit most of their energy via intense ionization leading to a very high density of localized electronic excitations. The energy transfer from electrons to lattice, within a time of electronic cooling ∼100 fs, is governed by the ‘electron-phonon coupling’ parameter g. In this work, GaAs is used as a model system for studying ionization-stimulated damage recovery. Controlled damage is introduced using 300 KeV Ar ion irradiation, followed by successive irradiation using 100 MeV Ag ions at ∼80 K by varying the fluence (ions cm−2). The TSM is utilized to explain the observed recovery. Using the previously published value of

g
=
3.2
×

1012 W cm−3 K−1 for GaAs, the existing thermal spike code resulted in melting and quick quenching within ∼10 ps, suggesting the formation of SHI-induced tracks. However, experimental observations do not support the formation of tracks in pristine GaAs. Multiple simulation runs, for different g values, predict that for no melting in GaAs, g should be

⩽

1.4 × 1012 W cm−3 K−1. Finally, the 3D version of the TSM is used to simulate the temperature profiles after an impact of SHI irradiation on an amorphous nano-zone embedded in a crystalline GaAs matrix. Simulations predict that the thermal spike in this zone is confined, indicating melt-flow at the crystalline-amorphous interface that can promote recovery. This lattice recovery is further supported by both RBS/C and TEM results.
Delocalization and insulator to metal transition in PEDOT:PSS
Authors: Mohan Arya , Menon Reghu
Published: October 2022

Charge transport in poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS), with systematic increase in the percentages of dimethyl sulfoxide (DMSO) and ethylene glycol (EG), is investigated as a function of temperature and electric field down to 4.2 K. The conductivity in pristine PEDOT:PSS (1.4 S cm−1) increased to 1070 S cm−1 with 10% of DMSO, and to 565 S cm−1 with 6% of EG. The conductivity ratio (

σ
r

=

σ

300K

/

σ

4

.2K

) is substantially reduced to 2.5 in 10% DMSO sample. This gradual transition from insulator (variable range hopping) to disordered metal (T
1/2 fit), with an intermediate critical regime (power law), is observed by small variations in the volume fractions of these solvents. The temperature dependence of the ratio of hopping length to localization length (

R

/

L

c

)

is rather weak for samples (2D & 4EG) near the transition. As the delocalization increases in more conducting samples, larger electric field dependence of conductivity is observed at lower fields (0.1 V cm−1). The real part of impedance decreases at higher frequency and the peak in the imaginary part of impedance shifts to higher frequency as the sample conductivity increases.
Importance of magnetic shape anisotropy in determining magnetic and electronic properties of monolayer VSi2P4
Authors: Guo San-Dong , Tao Yu-Ling , Cheng Kai , Wang Bing , Ang Yee Sin
Published: October 2022

Two-dimensional (2D) ferromagnets have been a fascinating subject of research, and magnetic anisotropy (MA) is indispensable for stabilizing the 2D magnetic order. Here, we investigate magnetic anisotropy energy (MAE), magnetic and electronic properties of

V
S

i
2

P
4

by using the generalized gradient approximation plus U approach. For large U, the magnetic shape anisotropy (MSA) energy has a more pronounced contribution to the MAE, which can overcome the magnetocrystalline anisotropy (MCA) energy to evince an easy-plane. For fixed out-of-plane MA, monolayer

V
S

i
2

P
4

undergoes ferrovalley (FV), half-valley-metal (HVM), valley-polarized quantum anomalous Hall insulator (VQAHI), HVM and FV states with increasing U. However, for assumptive in-plane MA, there is no special quantum anomalous Hall (QAH) state and spontaneous valley polarization within considered U range. According to the MAE and electronic structure with fixed out-of-plane or in-plane MA, the intrinsic phase diagram shows common magnetic semiconductor, FV and VQAHI in monolayer

V
S

i
2

P
4

. At representative U = 3 eV widely used in references,

V
S

i
2

P
4

can be regarded as a 2D-XY magnet, not Ising-like 2D long-range order magnets predicted in previous works with only considering MCA energy. Our findings shed light on importance of MSA in determining magnetic and electronic properties of monolayer

V
S

i
2

P
4

.
Automated weak signal frequency estimation method based on Duffing oscillator and particle swarm optimization
Authors: Wang Yifan , Cheng Yuhua , Wang Li , Yan Yanjun , Zou Songting , Chen Kai
Published: October 2022

The frequency of a weak signal is used for fault diagnosis and target identification in various fields. By introducing particle swarm optimization (PSO) and spectral entropy (SE), an automated weak signal frequency estimation method based on the Duffing oscillator is proposed. The proposed method uses the differential structure to enhance the timing difference of the Duffing oscillator between the chaotic and large-scale periodic states, which is quantitatively distinguished by SE. Then, the frequency of the internal driving force is adaptively adjusted by the PSO to allow the SE to reach a minimum value where the driving frequency equals the weak signal frequency. A group of weak signals with different frequencies has been tested. The maximum relative frequency error is only 0.68%. Unlike other chaotic oscillator-based frequency estimation methods, the proposed method does not need to determine the phase state manually. A rough initial frequency search range is sufficient for automatic frequency measurement of the proposed method in this paper.
Novel scanning system with error separation for high-accuracy profile measurement
Authors: Guo Jingyang , Zhai Dede , Chen Shanyong , Liu Junfeng
Published: October 2022

This paper proposes a method based on a single-probe scanning system for measuring the profile error of an artifact. Our system employs the movement accuracy of a single sensor to achieve a virtual multi-sensor configuration that can function like a traditional multi-sensor. This novel virtual multi-probe scanning system and its corresponding method have the following benefits: (a) A high-accuracy profile can be reconstructed free of the guidance error of the scanning stage. The reconstructed profile has a very high lateral resolution, depending on the lateral resolution (µm level) of the probe. (b) Sensor drift can be restrained using our method, based on the principle of differential reconstruction. The high steep profile can also be measured with a scanning system moving along the measuring direction, thus extending the measuring range. We developed the measurement system and tested the effects of noise, drift, and other factors on the reconstruction results. Finally, some optical surfaces were measured, and comparisons were made between the results obtained from our method and those of a Zygo interferometer. There was high agreement between the two methods, with a deviation of approximately 0.1 μm.
Fast algorithm for time decay estimation with applications to electrostatic ion beam traps
Authors: Trigano T , Fradkin Z
Published: October 2022

The ability of peptide trapping in an electrostatic ion beam trap (EIBT) is used for the measurement of renin substrate lifetime dependence from the pressure. The time decay estimation is traditionally obtained by optimization of nonlinear curve-fitting in the least-squares sense. This paper presents a novel algorithm to address this problem, using a numerical differentiation method as the basis for lifetime estimation. Simulations results show that the proposed method provides results similar to those obtained with the classical approach, but is faster by about two orders of magnitude. An experimental result is detailed, which shows the adequacy of this algorithm for the real-life monitoring of decay measurements, not only for EIBT, but also for other processes such as luminescence where exponential decay is involved.
Error compensation for phase retrieval in deflectometry based on deep learning
Authors: Guan Jingtian , Li Ji , Yang Xiao , Chen Xiaobo , Xi Juntong
Published: October 2022

Fringe patterns are widely applied in optical metrology, and phase retrieval is an essential process for decoding surface information. In the field of phase measuring deflectometry (PMD), phase errors in the phase retrieval process have more significant effects for PMD is a slope-based technique and is more sensitive to low-frequency errors. The main factors affecting the quality of the captured fringe images include the gamma effect of the liquid crystal display screen, the random noise from the charge-coupled device camera, and the random noise amplified by the defocused fringe patterns. Conventional methods compensated the phase errors of these factors separately with different methods, which are inefficient in handling the errors from coupling factors effectively. In this paper, we propose a deep neural network to compensate for the phase errors resulting from the combination of the factors. Experimental results demonstrate that the proposed network can significantly suppress the errors in phase retrieval with non-ideal fringe images. The phase errors can be reduced in both simulated and authentic data for deflectometry, which verifies the robustness and effectiveness of the proposed method.
Highly sensitive triethylamine gas sensor by Pt-loaded p–n heterojunction Co3O4/WO3
Authors: Song Zhenlin , Zeng Jiyang , Zi Baoye , Chen Fengying , Zhang Yumin , Zhang Genlin , Zhu Zhongqi , Zhang Jin , Liu Qingju
Published: October 2022

Triethylamine (TEA) exists widely in production and life and is extremely volatile, which seriously endangers human health. It is required to develop high-performance TEA sensors to protect human health. We fabricated Pt-Co3O4/WO3 based on our previous work, and the performance was tested against volatile organic compounds. Compared with the previous work, its operating temperature was greatly reduced from 240 °C to 180 °C. The response value of Pt-Co3O4/WO3 was increased from 1101 to 1532 for 10 ppm TEA with good selectivity. These results show a significant step toward practical use of the Pt-Co3O4/WO3 sensor.
Measurement of wave propagation through a tube using dual transducers for elastography in arteries
Authors: Lee Hyoung-Ki , Capron Charles B , Liu Hsiao-Chuan , Roy Tuhin , Guddati Murthy N , Greenleaf James F , Urban Matthew W
Published: October 2022

Objective. Measuring waves induced with acoustic radiation force (ARF) in arteries has been studied over the last decade. To date, it remains a challenge to quantitatively assess the local arterial biomechanical properties. The cylindrical shape and waveguide behavior of waves propagating in the arterial wall pose complexities to determining the mechanical properties of the artery. Approach. In this paper, an artery-mimicking tube in water is examined utilizing three-dimensional measurements. The cross-section of the tube is measured while a transducer is translated over 41 different positions along the length of the tube. Motion in the radial direction is calculated using two components of motion which are measured from the two orthogonal views of the cross-section. This enables more accurate estimation of motion along the circumference of tube. Main results. The results provide more information to categorize the motion in tube wall into two types of responses: a transient response and a steady state response. The transient response is caused by ARF application and the waves travel along the length of the tube for a relatively short period of time. This corresponds to the axial and circumferential propagating waves. The two circumferential waves travel along the circumference of tube in CW (clockwise) and CCW (counter-clockwise) direction and result in a standing wave. By using a directional filter, the two waves were successfully separated, and their propagation was more clearly visualized. As a steady state response, a circumferential mode is generated showing a symmetric motion (i.e. the proximal and distal walls move in the opposite direction) following the transient response. Significance. This study provides a more comprehensive understanding of the waves produced in an artery-mimicking tube with ARF application, which will provide opportunities for improving measurement of arterial mechanical properties.
3D model-based super-resolution motion-corrected cardiac T1 mapping
Authors: Hufnagel Simone , Metzner Selma , Kerkering Kirsten Miriam , Aigner Christoph Stefan , Kofler Andreas , Schulz-Menger Jeanette , Schaeffter Tobias , Kolbitsch Christoph
Published: October 2022

Objective. To provide 3D high-resolution cardiac T1 maps using model-based super-resolution reconstruction (SRR). Approach. Due to signal-to-noise ratio limitations and the motion of the heart during imaging, often 2D T1 maps with only low through-plane resolution (i.e. slice thickness of 6–8 mm) can be obtained. Here, a model-based SRR approach is presented, which combines multiple stacks of 2D acquisitions with 6–8 mm slice thickness and generates 3D high-resolution T1 maps with a slice thickness of 1.5–2 mm. Every stack was acquired in a different breath hold (BH) and any misalignment between BH was corrected retrospectively. The novelty of the proposed approach is the BH correction and the application of model-based SRR on cardiac T1 Mapping. The proposed approach was evaluated in numerical simulations and phantom experiments and demonstrated in four healthy subjects. Main results. Alignment of BH states was essential for SRR even in healthy volunteers. In simulations, respiratory motion could be estimated with an RMS error of 0.18 ± 0.28 mm. SRR improved the visualization of small structures. High accuracy and precision (average standard deviation of 69.62 ms) of the T1 values was ensured by SRR while the detectability of small structures increased by 40%. Significance. The proposed SRR approach provided T1 maps with high in-plane and high through-plane resolution (1.3 × 1.3 × 1.5–2 mm3). The approach led to improvements in the visualization of small structures and precise T1 values.
Developing magnetorelaxometry imaging for human applications
Authors: Arsalani Soudabeh , Radon Patricia , Schier Peter , Jaufenthaler Aaron , Liebl Maik , Baumgarten Daniel , Wiekhorst Frank
Published: October 2022

Objective. Magnetic nanoparticles (MNPs) are a promising tool in biomedical applications such as cancer therapy and diagnosis, where localization and quantification of MNP distributions are often mandatory. This can be obtained by magnetorelaxometry imaging (MRXI). Approach. In this work, the capability of MRXI for quantitative imaging of MNP inside larger volumes such as a human head is investigated. We developed a human head phantom simulating a glioblastoma multiforme (GBM) tumor containing MNP for magnetic hyperthermia treatment. The sensitivity of our MRXI setup for detection of MNP concentrations in the range of 3–19 mg cm−3 was studied. Main result. The results show the high capability of MRXI to detect MNPs in a human head sized volume. Superficial sources with a concentration larger than 12 mg cm-3 could be reconstructed with a resulotion of about 1 cm-3. Significance. The reconstruction of the MNP distribution, mimicking a GBM tumor of 7 cm3 volume with clinically relevant iron concentration, demonstrates the in vivo feasibility of MRXI in humans.
Investigation of raman spectrum, structural, morphological, and optical features of Fe2O3 and Fe2O3/reduced graphene oxide hybrid nanocomposites
Authors: Abdel-Salam Ahmed I , Gomaa Islam , Khalid A , Soliman T S
Published: October 2022

The Hematite (Fe2O3) nanoparticles and Fe2O3-reduced graphene oxide (rGO) nanocomposite were successfully synthesized via co-precipitation method. The rGO was used as passivation layer to improve the optical properties of the Fe2O3. X-ray diffraction, transmission electron microscopy, Raman, and Fourier transform-infrared spectroscopy were used to investigate the modification in the Fe2O3 structure in the presence of rGO. UV-visible absorption spectra were investigated, and the optical bandgap was determined. Using different relations like Moss, Rivandra, Anani, and others, the refractive index was calculated depending on the obtained optical bandgap. The refractive index values were compared with the data calculated from Duffy relation and good accordance was found between them. The optical bandgap and electronegativity were found to decrease by the addition of rGO in Fe2O3 matrix, while the refractive index was found to increase. Consequently, the Fe2O3-rGO nanocomposites capacity to control optical properties makes it a perfect contender for a variety of applications.
Absorbing boundary condition as limiting case of imaginary potentials
Authors: Tumulka Roderich
Published: October 2022

Imaginary potentials such as V(x) = −iσ1Ω(x) (with σ > 0 a constant, Ω a subset of 3-space, and 1Ω its characteristic function) have been used in quantum mechanics as models of a detector. They represent the effect of a ‘soft’ detector that takes a while to notice a particle in the detector volume Ω. In order to model a ‘hard’ detector (i.e. one that registers a particle as soon as it enters Ω), one may think of taking the limit σ → ∞ of increasing detector strength σ. However, as pointed out by Allcock, in this limit the particle never enters Ω; its wave function gets reflected at the boundary ∂Ω of Ω in the same way as by a Dirichlet boundary condition on ∂Ω. This phenomenon, a cousin of the ‘quantum Zeno effect,’ might suggest that a hard detector is mathematically impossible. Nevertheless, a mathematical description of a hard detector has recently been put forward in the form of the ‘absorbing boundary rule’ involving an absorbing boundary condition on the detecting surface ∂Ω. We show here that in a suitable (non-obvious) limit, the imaginary potential V yields a non-trivial distribution of detection time and place in agreement with the absorbing boundary rule. That is, a hard detector can be obtained as a limit, but it is a different limit than Allcock considered.
Electron thermal internal transport barriers triggered by the effect of ion shielding
Authors: Ye Lei , Luo Zhengping , Xiao Xiaotao , Pan Chengkang , Wang Yuehang , Huang Yao , Zang Qing , Chen Fei , Jin Yifei , Wang Shouxin , Ding Bojiang , Xiao Bingjia , Wang Shaojie
Published: October 2022

The formation of electron thermal internal transport barriers (eITBs) is investigated by critical gradient threshold analysis for recent EAST experiments with dominant RF heating and low torque injection. The ratio of electron temperature to ion temperature, τ = T
e/T
i, is identified to be the key parameter that triggers eITB in the hot electron mode through electron turbulence suppression by the effect of ion shielding. The critical gradient of electron-temperature-gradient turbulence can be greatly increased with τ due to strong electron heating and weak electron–ion energy coupling. The formation and evolution of eITB is found to be determined by the critical temperature gradient of electron turbulence.
Selective Separation of Gases by Metal Organic Framework Materials (Mofs)
Authors: Hu Jiayi , Wang Yining , Wu Leyi
Published: October 2022

Gas separation is used to separate one or more gases from a mixture, which is crucial in the chemical industry. Compared with conventional porous materials, the distinctive physicochemical traits of MOFs play a dominant role in gas storage and separation. This review focuses on MOF materials in selective gas separation and current challenges. According to research, the usage of porous materials has achieved effective separation and greatly reduced energy consumption in nitrogen/oxygen (N2/O2) separation, acetylene/ethylene (C2H2/C2H4) separation, carbon capture and toxic gas separation. MOF’s unique structural features lead to the promising status for gas storage and separation. However, MOF materials still have some problems and challenges, e.g., the lack of practice for scientists to easily find a high-performance MOFs, high cost of MOF materials and shaping process. In the future, researchers around the world are looking to synthesize more and more artificial MOFs. Overall, these results offer a guideline for improvement of MOF materials.
Implementation of a home-made high accuracy pulsimeter and oximeter
Authors: Fernández-Alonso F.J. , Pau J.L. , Redondo-Cubero A.
Published: October 2022

Heart rate and blood oxygen saturation level are essential medical parameters that can be measured optically by photoplethysmography. However, certain individuals present variability in skin absorption that can affect the proper quantification of both pulse and blood oxygen level. In this work, we designed an optical device capable of measuring these variables, trying to improve the accuracy by means of different electronic signal processing. A final accuracy of 0.5 beats per minute and 0.5% was determined for the heart rate and the oxygen saturation measurements, respectively. The sensor was used in one practical study with more than 100 participants where the resting heart rate and the pulse waveform were analyzed. Resting heart rate was shown to decrease with age and increase with BMI. Overall, the device performance makes it suitable to be used in the medical field and sports science.
An assisted decision-making tool for synchrotron beamline alignment based on neural networks
Authors: Yan Ruyu , Yang Yiming , Xing Chengye , liu Peng , Chang Guangcai
Published: October 2022

To achieve an excellent focus quality, the parameters of optical elements (OEs) are, in most of the synchrotron beamlines, manually adjusted.
This procedure is not only time-consuming and experience-dependent but also extremely complex when various experimental requirements are involved.
Responding to this challenge, we propose a new beamline alignment tool based on neural network-assisted design.
This method can predict the parameters of OEs, according to experimental requirements.
Specifically, the artificial neural network (ANN) training set is generated, based on SHADOW3 and Synchrotron Radiation Workshop (SRW) in OASYS.
Then, the magnification factor (M) of the focusing lens and the position (P) of the secondary source is predicted, using the aforesaid tool.
Finally, the parameters are verified by substituting back to the OASYS.
The results show that learned NNs can predict the main parameters of the OEs with high accuracy (above 97%).
Then bring the parameters above back to the OASYS software to obtain the re-tracing results.
Furthermore, the final focused quality at the sample point satisfies the experimental design indicators.
Experimental design indicators are flux, full width at half-maximum (FWHM) at the sampling point and transmission efficiency.
Compared to other methods, this is a successful exploration of the ANN in the field of synchrotron beamline alignment, and
it is an important guide for the design of beamlines alignment.
Biohybrid robots: recent progress, challenges, and perspectives
Authors: Webster-Wood Victoria A , Guix Maria , Xu Nicole W , Behkam Bahareh , Sato Hirotaka , Sarkar Deblina , Sanchez Samuel , Shimizu Masahiro , Parker Kevin Kit
Published: October 2022

The past ten years have seen the rapid expansion of the field of biohybrid robotics. By combining engineered, synthetic components with living biological materials, new robotics solutions have been developed that harness the adaptability of living muscles, the sensitivity of living sensory cells, and even the computational abilities of living neurons. Biohybrid robotics has taken the popular and scientific media by storm with advances in the field, moving biohybrid robotics out of science fiction and into real science and engineering. So how did we get here, and where should the field of biohybrid robotics go next? In this perspective, we first provide the historical context of crucial subareas of biohybrid robotics by reviewing the past 10+ years of advances in microorganism-bots and sperm-bots, cyborgs, and tissue-based robots. We then present critical challenges facing the field and provide our perspectives on the vital future steps toward creating autonomous living machines.