bluuebunny/crossref_metadata_2025 huggingface dataset:
Size-dependent melting of onion-like fullerenic carbons: a molecular dynamics and machine learning study
Authors: Fu Ran , Xu Yihua , Qiao Shi , Liu Yisi , Lin Yanwen , Li Yang , Zhang Zhisen , Wu Jianyang
Published: August 2022

The melting thermodynamic characteristics of 2- to 20-layered onion-like fullerenes (OLF
n
) (C60@C240 to C60@···@C6000···@C24000) are comprehensively explored using first-principles-based ReaxFF atomistic simulations and random forest machine learning (RF ML). It is revealed that OLF
n
shows lower thermal stability than the counterparts of single-walled fullerenes (SWF
n
). The melting point of SWF
n
increases monotonically with increasing size, whereas for OLF
n
, an unusual size-dependent melting point is observed; OLF
n
with intermediate size shows the highest melting point. For small OLF
n
, the melting occurs from the inner to the outer, whereas for large OLF
n
, it nucleates from the inner to the outer and to intermediate fullerenes. The melting and erosion behaviors of both SWF
n
and OLF
n
are mainly characterized by the nucleation of non-hexagons, nanovoids, carbon chains and emission of C2. RF ML model is developed to predict the melting points of both SWF
n
and OLF
n
. Moreover, the analysis of the feature importance reveals that the Stone-Wales transformation is a critical pathway in the melting of SWF
n
and OLF
n
. This study provides new insights and perspectives into the thermodynamics and pyrolysis chemistry of fullerenic carbons, and also may shed some lights onto the understanding of thermally-induced erosion of carbon-based resources and spacecraft materials.
Visual perception of surface roughness via maximum variance direction of image patches
Authors: Zou Lingyun , Jiang Jun , Deng Gaoxu , Wu Shiqian
Published: August 2022

Most existing visual roughness perception algorithms are pixel-wised operations, which lead to unstable roughness measurements. To address this problem, a novel visual roughness perception in the maximum variance direction of image patches is proposed in this article. Specifically, each patch is assumed to be a point in a multi-dimensional Euclidean space. To improve the signal-to-noise ratio of roughness, all points are projected onto its maximum variance direction based on principal component analysis. In this direction, the variance of these points is characterized as roughness. A new roughness metric dataset is constructed by scanned images of sandpapers with different mesh sizes to verify the effectiveness of the proposed algorithm. Experiments on the dataset show the proposed method outperforms many computer vision-based methods, such as the gray-level co-occurrence matrix approach and the

G

a

approach.
Research on a pavement pothole extraction method based on vehicle-borne continuous laser scanning point cloud
Authors: Rufei Liu , Jiben Yang , Hongwei Ren , Bori Cong , Chenhao Chang
Published: August 2022

Automatic detection and rapid extraction of condition characteristics of pavement potholes provide important support for road health monitoring and maintenance. In this paper, a method of extracting pavement potholes in vehicle-borne continuous laser point cloud combined with two-dimensional and three-dimensional analysis is proposed. This method mainly includes three parts: Firstly, point cloud data preprocessing is carried out to remove non-road point cloud and road noise points; then the transverse and longitudinal sections of the road are extracted according to the scanning line index of the laser point cloud. The Douglas–Pucker operator is used to analyse the profile contour characteristics, and the integral invariant operator is used to identify the initial feature points of the pothole; finally, the local datum surface of the pavement is constructed by fitting, and the continuous depth image of the pavement is generated. The active contour model operator is used to accurately extract the pothole boundary based on the local depth information, and geometric information such as the depth and area of the pothole is obtained. Selecting some road point cloud data for experiments, the results show that the pothole feature point extraction method in this paper is relatively robust, the extraction precision rate reaches 86.1%, and the recall rate reaches 91.2%. By generating a local depth image for precise extraction of the pothole boundary, it can effectively solve the problem of inaccurate extraction of the pothole boundary based on discrete point clouds. Compared with the manual measurement results, the relative error of the area is less than 7%, and the relative error of the depth is less than 6%, which proves the effectiveness of this method.
Shape reconfiguration and functional self-healing of thermadapt shape memory epoxy vitrimers by exchange reaction of disulfide bonds
Authors: Li Ben , Zhu Guangming , Hao Yujia , Ren Tianning
Published: August 2022

Epoxy-based shape memory materials still face many challenges from preparation to application. Designing dynamic covalent bonds into the cross-linked network of epoxy can bring many new properties to them, which is expected to solve some of the problems faced. In this paper, epoxy vitrimers with different contents of exchangeable disulfide bonds were synthesized by the polymerization of hydrogenated epoxy resins with diacids containing dynamic disulfide bonds. The effect of disulfide bond content on the properties of epoxy vitrimers was systematically studied. By activating the exchange reaction of disulfide bonds, the permanent shape of epoxy vitrimers can be reconfigured, even from two to three dimensions. The time required for reconfiguring is affected by the content of disulfide bonds, the more disulfide bonds, the shorter the time required. The epoxy vitrimers with more content of disulfide bonds were found to have lower recovery ratio loss after the same shape memory cycle by thermal bending experiments. More importantly, the epoxy vitrimers with more content of disulfide bonds also exhibited better functional self-healing properties. The decreased recovery ratio can be healed by periodic heat treatment, thus ensuring that the epoxy vitrimers perform more shape memory cycles and maintain a high shape recovery ratio. These experimental results will serve as a basis for expanding the range of applications and prolonging the service life of epoxy-based shape memory materials.
Protecting quantum entanglement in thermal reservoir by detuning
Authors: Zhang Chi , Yang Jianhe
Published: August 2022

In this work, the quantum entanglement dynamics of a two-atom system in the thermal reservoir is investigated. An analytical solution of the single atom in the thermal reservoir and the expression of the quantum entanglement of the two-atom system in the thermal reservoir are obtained by the Markovian master equation method. The results showed that the nonzero temperature leads to sudden death of entanglement under the weak coupling limit. The higher the temperature, the faster the decay of entanglement. In particular, the detuning and the smaller spectrum width in the weak atom-reservoir coupling regime can effectively protect the quantum entanglement of the two-atom system in the thermal reservoir under the weak atom-reservoir coupling regime. The corresponding physical explanation is given by the entropy production rare.
Field-level inference of galaxy intrinsic alignment from the SDSS-III BOSS survey
Authors: Tsaprazi Eleni , Nguyen Nhat-Minh , Jasche Jens , Schmidt Fabian , Lavaux Guilhem
Published: August 2022

As a large-scale overdensity collapses, it affects the orientation and shape of galaxies that form, by exerting tidal shear along their axes. Therefore, the shapes of elliptical galaxies align with the tidal field of cosmic structures. This intrinsic alignment provides insights into galaxy formation and the primordial universe, complements late-time cosmological probes and constitutes a significant systematic effect for weak gravitational lensing observations. In the present study, we provide constraints on the linear alignment model using a fully Bayesian field-level approach, using galaxy shape measurements from the SDSS-III BOSS LOWZ sample and three-dimensional tidal fields constrained with the LOWZ and CMASS galaxy samples of the SDSS-III BOSS survey. We find 4σ evidence of intrinsic alignment, with an amplitude of AI
= 2.9 ± 0.7 at 20 Mpch.
Radio bounds on the mixed dark matter scenarios of primordial black holes and WIMPs
Authors: Kadota Kenji , Tashiro Hiroyuki
Published: August 2022

We study the synchrotron radio emission in the mixed dark matter scenarios consisting of the primordial black holes (PBHs) and the self-annihilating WIMPs (weakly interacting massive particles). The WIMPs can form the ultracompact minihalos around PBHs and the annihilation enhancement from these dense halos can lead to the efficient synchrotron radiation at the radio frequency in the presence of galactic magnetic fields.
The upper bound of PBH fraction with respect to the total dark matter abundance is of order 10-8 ∼ 10-5 depending on the electroweak scale WIMP mass (mχ
= 10 ∼ 1000 GeV) and the WIMP annihilation channel (e.g. a hadronic χχ ⟶ bb̅ or a leptonic χχ ⟶ e
+
e
- channel). The PBH contribution to the total dark matter abundance is hence negligible when the other component of dark matter is composed of the conventional electroweak scale WIMPs.
Wave function of the universe in the presence of trans-Planckian censorship
Authors: Mondal Vikramaditya
Published: August 2022

The wave function for a closed de Sitter universe has been
computed, demanding consistency with the recently proposed
Trans-Planckian Censorship Conjecture (TCC). We extend the
Einstein-Hilbert action to contain a complex-valued term which
provides an exponentially decaying weight for the geometries
violating TCC in the Lorentzian path integral sum while working in
the minisuperspace approach to quantum cosmology. This
postulated modification suppresses the probability of
evolution of the universe into configurations that violate TCC. We
show that due to the presence of this suppression factor, the Hubble
rate of the universe at the end of the inflation gets subdued and
assumes a value less than what is expected classically. Moreover,
the consequences of this quantum gravity motivated correction in the
primordial power spectrum are discussed as well.
Research on 946 nm LG01 mode laser considering thermal effect
Authors: Yang Yashuai , Li Yongliang , Wang Chi , Yang Chao
Published: August 2022

Laguerre–Gaussian (LG) beams have important application prospects in Frontier Fields such as optical micromanipulation, optical communication, and super-resolution microscopy. In this letter, the thermal effect generated by Nd:YAG crystal that is end-pumped by the annular-beam is taken into account in the analysis of the LG01 mode beam generation. The 946 nm LG01 mode laser is obtained by using annular-beam end-pumped Nd:YAG crystal shaped by custom mirror M01. When the incident pump power is 19.9 W, the maximum output power is 1.35 W, the optical-optical conversion efficiency is 6.8%, the slope efficiency is 10.9%, and the beam quality factor M2 in X and Y directions is 2.22 and 2.28 respectively. The handedness of LG01 mode laser remains stable in the whole pump range. The theoretical model established considering thermal effects can guide the design of LG mode lasers, and the 946 nm LG01 mode laser obtained expands the new wavelength of vortex light and increases its potential new application direction.
A 4H-SiC trench IGBT with controllable hole-extracting path for low loss
Authors: Wu Lijuan , Liu Heng , Song Xuanting , Chen Xing , Zeng Jinsheng , Qiu Tao , Zhang Banghui
Published: August 2022

A novel 4H-SiC trench insulated gate bipolar transistor (IGBT) with a controllable hole-extracting (CHE) path is proposed and investigated in this paper. The CHE path is controlled by metal semiconductor gate (MES gate) and metal oxide semiconductor gate (MOS gate) in the p-shield region. The grounded p-shield region can significantly suppress the high electric field around gate oxide in SiC devices, but it weakens the conductivity modulation in the SiC trench IGBT by rapidly sweeping out holes. This effect can be eliminated by introducing the CHE path. The CHE path is pinched off by the high gate bias voltage at on-state to maintain high conductivity modulation and obtain a comparatively low on-state voltage (V
ON). During the turn-off transient, the CHE path is formed, which contributes to a decreased turn-off loss (E
OFF). Based on numerical simulation, the E
OFF of the proposed IGBT is reduced by 89% compared with the conventional IGBT at the same V
ON and the V
ON of the proposed IGBT is reduced by 50% compared to the grounded p-shield IGBT at the same E
OFF. In addition, the average power reduction for the proposed device can be 51.0% to 81.7% and 58.2% to 72.1% with its counterparts at a wide frequency range of 500 Hz to 10 kHz, revealing a great improvement of frequency characteristics.
An insulated-gate bipolar transistor model based on the finite-volume charge method
Authors: Zhang Manhong , Wu Wanchen
Published: August 2022

A finite-volume charge method has been proposed to simulate PIN diodes and insulated-gate bipolar transistor (IGBT) devices using SPICE simulators by extending the lumped-charge method. The new method assumes local quasi-neutrality in the undepleted N− base region and uses the total collector current, the nodal hole density and voltage as the basic quantities. In SPICE implementation, it makes clear and accurate definitions of three kinds of nodes — the carrier density nodes, the voltage nodes and the current generator nodes — in the undepleted N− base region. It uses central finite difference to approximate electron and hole current generators and sets up the current continuity equation in a control volume for every carrier density node in the undepleted N− base region. It is easy to increase the number of nodes to describe the fast spatially varying carrier density in transient processes. We use this method to simulate IGBT devices in SPICE simulators and get a good agreement with technology computer-aided design simulations.
Effect of thickness of antimony selenide film on its photoelectric properties and microstructure
Authors: Liu Xin-Li , Weng Yue-Fei , Mao Ning , Zhang Pei-Qing , Lin Chang-Gui , Shen Xiang , Dai Shi-Xun , Song Bao-An
Published: August 2022

Antimony selenide (Sb2Se3) films are widely used in phase change memory and solar cells due to their stable switching effect and excellent photovoltaic properties. These properties of the films are affected by the film thickness. A method combining the advantages of Levenberg–Marquardt method and spectral fitting method (LM–SFM) is presented to study the dependence of refractive index (RI), absorption coefficient, optical band gap, Wemple–DiDomenico parameters, dielectric constant and optical electronegativity of the Sb2Se3 films on their thickness. The results show that the RI and absorption coefficient of the Sb2Se3 films increase with the increase of film thickness, while the optical band gap decreases with the increase of film thickness. Finally, the reasons why the optical and electrical properties of the film change with its thickness are explained by x-ray diffractometer (XRD), energy dispersive x-ray spectrometer (EDS), Mott–Davis state density model and Raman microstructure analysis.
Anomalous strain effect in heteroepitaxial SrRuO3 films on (111) SrTiO3 substrates
Authors: Wang Zhenzhen , Qi Weiheng , Bi Jiachang , Li Xinyan , Chen Yu , Yang Fang , Cao Yanwei , Gu Lin , Zhang Qinghua , Wang Huanhua , Zhang Jiandi , Guo Jiandong , Liu Xiaoran
Published: August 2022

We report comprehensive investigations into the structure of high-quality (111)-oriented SrRuO3 films on SrTiO3 substrates to elucidate the effect of (111) heteroepitaxial strain. We found that SrRuO3 film with a thickness of ∼ 40 nm is compressively strained in plane on the substrate with full coherency. Nevertheless, the out-of-plane spacing is almost the same as in the bulk, which is at odds with the conventional paradigm. By probing a series of half-order Bragg reflections using synchrotron-based x-ray diffraction combined with analyses of the scanning transmission electron microscopy images, we discovered that the heteroepitaxial strain is accommodated via significant suppression of the degree of c
+ octahedral tilting and the formation of three equivalent domain structures on the (111) SrTiO3 substrate. This anomalous effect sheds light on the understanding of an unconventional paradigm of film–substrate coupling for the (111) heteroepitaxial strain.
Raman lasing and other nonlinear effects based on ultrahigh-QCaF2 optical resonator
Authors: Xing Tong , Xing Enbo , Jia Tao , Li Jianglong , Rong Jiamin , Zhou Yanru , Liu Wenyao , Tang Jun , Liu Jun
Published: August 2022

The calcium fluoride (CaF2) whispering gallery mode crystalline resonator is an excellent platform for nonlinear optical applications because of the decreasing in threshold caused by ultrahigh quality (Q) factor. In this paper, we achieved the observation of Raman lasing, first-order Raman comb, and second-order Raman lasing in a CaF2 disk resonator with a diameter of 4.96 mm and an ultrahigh-Q of 8.43×108 at 1550-nm wavelength. We also observed thermal effects in CaF2 disk resonator, and the threshold of thermo-optical oscillation is approximately coincident with Raman lasing, since the intracavity power increases rapidly when the power reaches the threshold, and higher input pump power results in longer thermal drift and higher Raman emission power. With a further increase in pump power, the optical frequency combs range is from 1520 nm to 1650 nm, with a wavelength interval of 4×FSR. It is a promising candidate for optical communication, biological environment monitoring, spectral analysis, and microwave signal sources.
A kind of multiwavelength erbium-doped fiber laser based on Lyot filter
Authors: Zhou Zhehai , Wu Jingyi , Min Kunlong , Zhao Shuang , Li Huiyu
Published: August 2022

A multiwavelength tunable ring-cavity erbium-doped fiber laser (EDFL) based on a Lyot filter was presented. For the proposed Lyot filter, a comb filter consisting of an EDF-polarization-maintaining fiber (EDF-PMF), a polarization controller (PC), and a circulator with four ports was used to suppress the mode competition. The light transmission direction was guaranteed by the circulator. For the proposed fiber laser, tunable single, dual, triple, quadruple, quintuple, sextuple, and septuple wavelengths were realized. A single-wavelength laser output with an optical signal-to-noise ratio (SNR) of up to 30.56 dB was realized, and a tuning range of 1590.54 nm to 1599.54 nm was achieved by tuning the PC. The stability of the single, dual, triple, and quadruple-wavelength center power fluctuations was less than 0.05 dB, 0.98 dB, 5.07 dB, and 7.71 dB respectively. When the laser was operated in the multiwavelength condition, the SNR was more than 20.97 dB. The proposed erbium-doped fiber laser is suitable for fiber-sensing system applications.
Intense low-noise terahertz generation by relativistic laser irradiating near-critical-density plasma
Authors: Zhang Shijie , Zhou Weimin , Yin Yan , Zou Debin , Zhao Na , Xie Duan , Zhuo Hongbin
Published: August 2022

Low-noise terahertz (THz) radiation over 100 MV/cm generation by a linearly-polarized relativistic laser pulse interacting with a near-critical-density (NCD) plasma slab is studied by theory and particle-in-cell (PIC) simulations. A theoretical model is established to examine the dipole-like radiation emission. The THz radiation is attributed to the single-cycle low-frequency surface current, which is longitudinally constrained by the quasi-equilibrium established by the laser ponderomotive force and the ponderomotively induced electrostatic force. Through theoretical analysis, the spatiotemporal characteristics, polarization property of the THz radiation, and the relation between the radiation strength with the initial parameters of driving laser and plasma are obtained, which are in good consistence with the PIC simulation results. Furthermore, it is found by PIC simulations that the generation of thermal electrons can be suppressed within the appropriate parameter regime, resulting in a clear THz radiation waveform. The appropriate parameter region is given for generating a low-noise intense THz radiation with peak strength reaching 100 MV/cm, which could find potential applications in nonlinear THz physics.
Conformational change-modulated spin transport at single-molecule level in carbon systems
Authors: Guo Yandong , Zhao Xue , Zhao Hongru , Yang Li , Lin Liyan , Jiang Yue , Ma Dan , Chen Yuting , Yan Xiaohong
Published: August 2022

Controlling the spin transport at the single-molecule level, especially without the use of ferromagnetic contacts, becomes a focus of research in spintronics. Inspired by the progress on atomic-level molecular synthesis, through first-principles calculations, we investigate the spin-dependent electronic transport of graphene nanoflakes with side-bonded functional groups, contacted by atomic carbon chain electrodes. It is found that, by rotating the functional group, the spin polarization of the transmission at the Fermi level could be switched between completely polarized and unpolarized states. Moreover, the transition between spin-up and spin-down polarized states can also be achieved, operating as a dual-spin filter. Further analysis shows that, it is the spin-dependent shift of density of states, caused by the rotation, that triggers the shift of transmission peaks, and then results in the variation of spin polarization. Such a feature is found to be robust to the length of the nanoflake and the electrode material, showing great application potential. Those findings may throw light on the development of spintronic devices.
Analytical model for Rayleigh-Taylor instability in conical target conduction region
Authors: Zhu Zhong-Yuan , Liu Yun-Xing , Li Ying-Jun , Zhang Jie
Published: August 2022

This work builds an isobaric steady-state fluid analytical-physical model of the plasma conduction region in a conical target. The hydrodynamic instability in the double-cone ignition scheme[21] for inertial confinement fusion (ICF) proposed by Zhang is studied with the built model. With this idealized model, the relevant parameters, such as density, temperature, and length of the plasma in the conduction region of the conical target under long-pulse conditions are given. The solution of the proposed analytical model dovetails with the trend of the numerical simulation. The model and results in this paper are beneficial for discussing how to attenuate Rayleigh–Taylor instability in ICF processes with conical and spherical targets.
Atomic structure and collision dynamics with highly charged ions
Authors: Ma Xinwen , Zhang Shaofeng , Wen Weiqiang , Huang Zhongkui , Hu Zhimin , Guo Dalong , Gao Junwen , Najjari Bennaceur , Xu Shenyue , Yan Shuncheng , Yao Ke , Zhang Ruitian , Gao Yong , Zhu Xiaolong
Published: August 2022

The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed. The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombination spectroscopy and VUV/x-ray spectroscopy. The collision dynamics part includes charge exchange dynamics in ion–atom collisions mainly in Bohr velocity region, ion-induced fragmentation mechanisms of molecules, hydrogen-bound and van de Waals bound clusters, interference, and phase information observed in ion–atom/molecule collisions. With this achievements, two aspects of theoretical studies related to low energy and relativistic energy collisions are presented. The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed. At the end of this review, some future prospects of research related to highly charged ions are proposed.
Experimental demonstration of a fast calibration method for integrated photonic circuits with cascaded phase shifters
Authors: Cao Junqin , Chen Zhixin , Wang Yaxin , Feng Tianfeng , Li Zhihao , Xing Zeyu , Li Huashan , Zhou Xiaoqi
Published: August 2022

With the development of research on integrated photonic quantum information processing, the integration level of the integrated quantum photonic circuits has been increasing continuously, which makes the calibration of the phase shifters on the chip increasingly difficult. For the calibration of multiple cascaded phase shifters that is not easy to be decoupled, the resources consumed by conventional brute force methods increase exponentially with the number of phase shifters, making it impossible to calibrate a relatively large number of cascaded phase shifters. In this work, we experimentally validate an efficient method for calibrating cascaded phase shifters that achieves an exponential increase in calibration efficiency compared to the conventional method, thus solving the calibration problem for multiple cascaded phase shifters. Specifically, we experimentally calibrate an integrated quantum photonic circuit with nine cascaded phase shifters and achieve a high-precision calibration with an average fidelity of 99.26%.
Quantum simulation of τ-anti-pseudo-Hermitian two-level systems
Authors: Zheng Chao
Published: August 2022

Different from the Hermitian case, non-Hermitian (NH) systems have novel properties and strongly relate to open and dissipative quantum systems. In this work, we investigate how to simulate τ-anti-pseudo-Hermitian systems in a Hermitian quantum device using linear combinations of unitaries and duality quantum algorithm. Specifying the τ to time-reversal (T) and parity-time-reversal (PT) operators, we construct the two NH two-level systems, design quantum circuits including three qubits, and decide the quantum gates explicitly in detail. We also calculate the success probabilities of the simulation. Experimental implementation can be expected in small quantum simulator.
Topological superconductivity in Janus monolayer transition metal dichalcogenides
Authors: Li Xian-Dong , Yu Zuo-Dong , Chen Wei-Peng , Gong Chang-De
Published: August 2022

The Janus monolayer transition metal dichalcogenides (TMDs) MXY (M = Mo, W, etc. and X, Y = S, Se, etc.) have been successfully synthesized in recent years. The Rashba spin splitting in these compounds arises due to the breaking of out-of-plane mirror symmetry. Here we study the pairing symmetry of superconducting Janus monolayer TMDs within the weak-coupling framework near critical temperature T
c, of which the Fermi surface (FS) sheets centered around both Γ and K (K′) points. We find that the strong Rashba splitting produces two kinds of topological superconducting states which differ from that in its parent compounds. More specifically, at relatively high chemical potentials, we obtain a time-reversal invariant s + f + p-wave mixed superconducting state, which is fully gapped and topologically nontrivial, i.e., a ℤ2 topological state. On the other hand, a time-reversal symmetry breaking d + p + f-wave superconducting state appears at lower chemical potentials. This state possess a large Chern number |C| = 6 at appropriate pairing strength, demonstrating its nontrivial band topology. Our results suggest the Janus monolayer TMDs to be a promising candidate for the intrinsic helical and chiral topological superconductors.
Accurate theoretical evaluation of strain energy of all-carboatomic ring (cyclo[2n]carbon), boron nitride ring, and cyclic polyacetylene
Authors: Lu Tian , Liu Zeyu , Chen Qinxue
Published: August 2022

Cyclocarbon fully consists of sp-hybridized carbon atoms, which shows quite unusual electronic and geometric structures compared to common molecules. In this work, we systematically studied strain energy (SE) of cyclocarbons of different sizes using regression analysis method based on electronic energies evaluated at the very accurate DLPNO-CCSD(T)/cc-pVTZ theoretical level. In addition, ring strain of two systems closely related to cyclocarbon, boron nitride (BN) ring, and cyclic polyacetylene (c-PA), is also explored. Very ideal relationships between SE and number of repeat units (n) are built for cyclo[2n]carbon, BnNn, and [2n]c-PA as SE = 555.0 ⋅n−1, 145.1⋅n−1, and 629.8⋅n−1kcal⋅mol−1, respectively, and the underlying reasons of the difference and similarity in their SEs are discussed from electronic structure perspective. In addition, force constant of harmonic potential of C–C–C angles in cyclocarbon is derived based on SE values, the result is found to be 56.23 kcal⋅mol−1⋅rad−2. The possibility of constructing homodesmotic reactions to calculate SEs of cyclocarbons is also explored in this work, although this method is far less rigorous than the regression analysis method, its result is qualitatively correct and has the advantage of much lower computational cost. In addition, comparisons show thatωB97XD/def2-TZVP is a good inexpensive alternative to the DLPNO-CCSD(T)/cc-pVTZ for evaluating energies used in deriving SE, while the popular and very cheap B3LYP/6-31G(d) level should be used with caution for systems with global electron conjugation such as c-PA.
High performance carrier stored trench bipolar transistor with dual shielding structure
Authors: Zhang Jin-Ping , Deng Hao-Nan , Zhu Rong-Rong , Li Ze-Hong , Zhang Bo
Published: August 2022

We propose a novel high performance carrier stored trench bipolar transistor (CSTBT) with dual shielding structure (DSS-CSTBT). The proposed DSS-CSTBT features a double trench structure with different trench profiles in the surface, in which a shallow gate trench is shielded by a deep emitter trench and a thick oxide layer under it. Compared with the conventional CSTBT (con-CSTBT), the proposed DSS-CSTBT not only alleviates the negative impact of the shallow gate trench and highly doped CS layer on the breakdown voltage (BV), but also well reduces the gate-collector capacitance C
GC, gate charge Q
G, and turn-off loss E
OFF of the device. Furthermore, lower turn-on loss E
ON and gate drive loss E
DR are also obtained. Simulation results show that with the same CS layer doping concentration N
CS = 1.5 × 1016 cm−3, the BV increases from 1312 V of the con-CSTBT to 1423 V of the proposed DSS-CSTBT with oxide layer thickness under gate (T
og2) of 1 μm. Moreover, compared with the con-CSTBT, the C
GC at V
CE of 25 V and miller plateau charge (Q
GC) for the proposed DSS-CSTBT with T
og2 of 1 μm are reduced by 79.4% and 74.3%, respectively. With the V
GE increases from 0 V to 15 V, the total Q
G for the proposed DSS-CSTBT with T
og2 of 1 μm is reduced by 49.5%. As a result, at the same on-state voltage drop (V
CEON) of 1.55 V, the E
ON and E
OFF are reduced from 20.3 mJ/cm2 and 19.3 mJ/cm2 for the con-CSTBT to 8.2 mJ/cm2 and 9.7 mJ/cm2 for the proposed DSS-CSTBT with T
og2 of 1 μm, respectively. The proposed DSS-CSTBT not only significantly improves the trade-off relationship between the V
CEON and E
OFF but also greatly reduces the E
ON.
Continuous-wave optical enhancement cavity with 30-kW average power
Authors: Liu Xing , Lu Xin-Yi , Wang Huan , Yan Li-Xin , Li Ren-Kai , Huang Wen-Hui , Tang Chuan-Xiang , Chiche Ronic , Zomer Fabian
Published: August 2022

Optical enhancement cavity (OEC) is a powerful tool for fundamental research and diagnostics. In this paper, the progress of a continuous-wave OEC to realize of megawatt cavity for a novel light source based on a steady-state microbunching (SSMB) mechanism, is reported. After efficiently suppressing all external noise and optimizing the alignment, mode-matching, and polarization matching, stable and long-term locking is achieved with the help of two feedback loops. The modal instability phenomenon caused by the surface thermoelastic deformation is observed. A pair of D-shape mirrors are utilized to remove the high-order modes. Finally, an intra-cavity average power of 30 kW is reached.
Inferring monosynaptic connections from paired dendritic spine Ca2+ imaging and large-scale recording of extracellular spiking
Authors: Xue Xiaohan , Buccino Alessio Paolo , Kumar Sreedhar Saseendran , Hierlemann Andreas , Bartram Julian
Published: August 2022

Objective: Techniques to identify monosynaptic connections between neurons have been vital for neuroscience research, facilitating important advancements concerning network topology, synaptic plasticity, and synaptic integration, among others. Approach: Here, we introduce a novel approach to identify and monitor monosynaptic connections using high-resolution dendritic spine Ca2+ imaging combined with simultaneous large-scale recording of extracellular electrical activity by means of high-density microelectrode arrays. Main results: We introduce an easily adoptable analysis pipeline that associates the imaged spine with its presynaptic unit and test it on in vitro recordings. The method is further validated and optimized by simulating synaptically-evoked spine Ca2+ transients based on measured spike trains in order to obtain simulated ground-truth connections. Significance: The proposed approach offers unique advantages as (a) it can be used to identify monosynaptic connections with an accurate localization of the synapse within the dendritic tree, (b) it provides precise information of presynaptic spiking, and (c) postsynaptic spine Ca2+ signals and, finally, (d) the non-invasive nature of the proposed method allows for long-term measurements. The analysis toolkit together with the rich data sets that were acquired are made publicly available for further exploration by the research community.
A sparse representation strategy to eliminate pseudo-HFO events from intracranial EEG for seizure onset zone localization
Authors: Besheli Behrang Fazli , Sha Zhiyi , Gavvala Jay R , Gurses Candan , Karamursel Sacit , Quach Michael M , Curry Daniel J , Sheth Sameer A , Francis David J , Henry Thomas R , Ince Nuri F
Published: August 2022

Objective. High-frequency oscillations (HFOs) are considered a biomarker of the epileptogenic zone in intracranial EEG recordings. However, automated HFO detectors confound true oscillations with spurious events caused by the presence of artifacts. Approach. We hypothesized that, unlike pseudo-HFOs with sharp transients or arbitrary shapes, real HFOs have a signal characteristic that can be represented using a small number of oscillatory bases. Based on this hypothesis using a sparse representation framework, this study introduces a new classification approach to distinguish true HFOs from the pseudo-events that mislead seizure onset zone (SOZ) localization. Moreover, we further classified the HFOs into ripples and fast ripples by introducing an adaptive reconstruction scheme using sparse representation. By visualizing the raw waveforms and time-frequency representation of events recorded from 16 patients, three experts labeled 6400 candidate events that passed an initial amplitude-threshold-based HFO detector. We formed a redundant analytical multiscale dictionary built from smooth oscillatory Gabor atoms and represented each event with orthogonal matching pursuit by using a small number of dictionary elements. We used the approximation error and residual signal at each iteration to extract features that can distinguish the HFOs from any type of artifact regardless of their corresponding source. We validated our model on sixteen subjects with thirty minutes of continuous interictal intracranial EEG recording from each. Main results. We showed that the accuracy of SOZ detection after applying our method was significantly improved. In particular, we achieved a 96.65% classification accuracy in labeled events and a 17.57% improvement in SOZ detection on continuous data. Our sparse representation framework can also distinguish between ripples and fast ripples. Significance. We show that by using a sparse representation approach we can remove the pseudo-HFOs from the pool of events and improve the reliability of detected HFOs in large data sets and minimize manual artifact elimination.
Characterization of a CdZnTe detector for a low-power CubeSat application
Authors: Lucchetta Giulio , Ackermann Markus , Berge David , Bloch Ingo , Bühler Rolf , Kolanoski Hermann , Lange Wolfgang , Zappon Francesco
Published: August 2022

We report spectral and imaging performance of a pixelated CdZnTe detector custom designed for theMeVCubeproject: a small Compton telescope on a CubeSat platform.MeVCubeis expected to cover the energy range between 200 keV and 4 MeV, with a sensitivity comparable to the one of the last generation of larger satellites. In order to achieve this goal, an energy resolution of few percent in full width at half maximum (FWHM) and a 3-D spatial resolution of few millimeters for the individual detectors are needed. The severe power constraints present in small satellites require very low power read-out electronics for the detector. Our read-out is based on the VATA450.3 ASIC developed byIdeas, with a power consumption of only 0.25 mW/channel, which exhibits good performance in terms of dynamic range, noise and linearity. A 2.0 cm× 2.0 cm× 1.5 cm CdZnTe detector, with a custom 8 × 8 pixel anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary read-out system for the cathode, based on a discreteAmptekA250F charge sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy resolution around 3% FWHM has been measured at a gamma energy of 662 keV; at 200 keV the average energy resolution is 6.5%, decreasing to ≲ 2% at energies above 1 MeV. A 3-D spatial resolution of ≈ 2 mm is achieved in each dimension.
A toy Monte Carlo simulation for the transverse polarization of high-energy electron beams
Authors: Chen S.H. , Huang Y.S. , Chen Y. , Duan Z. , Lou X.C. , Lan X.F. , Ruan M.Q. , Si M.Y. , Tang G.Y. , Wang Y.W. , Wang P.C. , Zhang J.Y.
Published: August 2022

Transversely-polarized beams are heuristic to the mechanism of CP violation and explore new physics. Besides, the transverse-polarization monitoring is a key point for the beam energy calibration by the resonant depolarization technique. In the article, the transverse polarization measurement of a high-energy electron beam is performed by Monte Carlo simulation on the circular electron-positron collider. The principle based on the Compton back-scattering combining a deflection magnetic field is discussed in detail. The physical presentation of the analyzing power is used to fit the asymmetric distribution of scattered electrons, which is proportional to the transverse polarization. Furthermore, we develop an efficient algorithm that obtain this analyzing power function and use different strategies to measure the transverse polarization for cross-check. Our measurement method is theoretically suitable with a statistical error 1% within few tens of seconds in Z pole on the circular electron-positron collider. The total systematic uncertainties are controlled to be about 0.6% related to the magnetic field, the drift distance, the laser polarization, the beam energy spread and the related uncertainties of a position sensitive detector.
Attribution of the 2020 surge in atmospheric methane by inverse analysis of GOSAT observations
Authors: Qu Zhen , Jacob Daniel J , Zhang Yuzhong , Shen Lu , Varon Daniel J , Lu Xiao , Scarpelli Tia , Bloom Anthony , Worden John , Parker Robert J
Published: August 2022

Atmospheric methane mixing ratio rose by 15 ppbv between 2019 and 2020, the fastest growth rate on record. We conduct a global inverse analysis of 2019–2020 Greenhouse Gases Observing Satellite observations of atmospheric methane to analyze the combination of sources and sinks driving this surge. The imbalance between sources and sinks of atmospheric methane increased by 31 Tg a−1 from 2019 to 2020, representing a 36 Tg a−1 forcing (direct changes in methane emissions and OH concentrations) on the methane budget away from steady state. 86% of the forcing in the base inversion is from increasing emissions (82 ± 18% in the nine-member inversion ensemble), and only 14% is from decrease in tropospheric OH. Half of the increase in emissions is from Africa (15 Tg a−1) and appears to be driven by wetland inundation. There is also a large relative increase in emissions from Canada and Alaska (4.8 Tg a−1, 24%) that could be driven by temperature sensitivity of boreal wetland emissions.
Spatiotemporal dynamics of global population and heat exposure (2020–2100): based on improved SSP-consistent population projections
Authors: Li Mengya , Zhou Bing-Bing , Gao Minyi , Chen Yimin , Hao Ming , Hu Guohua , Li Xia
Published: August 2022

To address future environmental change and consequent social vulnerability, a better understanding of future population (FPOP) dynamics is critical. In this regard, notable progress has been made in producing FPOP projections that are consistent with the Shared Socioeconomic Pathways (SSPs) at low resolutions for the globe and high resolutions for specific regions. Building on existing endeavors, here we contribute a new set of 1 km SSP-consistent global population projections (FPOP in short for the dataset) under a machine learning framework. Our approach incorporates a recently available SSP-consistent global built-up land dataset under the Coupled Model Intercomparison Project 6, with the aim to address the misestimation of future built-up land dynamics underlying existing datasets of future global population projections. We show that the overall accuracy of our FPOP outperforms five existing datasets at multiple scales and especially in densely-populated areas (e.g. cities and towns). Followingly, FPOP-based assessments of future global population dynamics suggest a similar trend by population density and a spatial Matthew effect of regional population centralization. Furthermore, FPOP-based estimates of global heat exposure are around 300 billion person-days in 2020 under four SSP-Representative Concentration Pathway (RCPs), which by 2100 could increase to as low as 516 billion person-days under SSP5-RCP4.5 and as high as 1626 billion person-days under SSP3-RCP8.5—with Asia and Africa contributing 64%–68% and 21%–25%, respectively. While our results shed lights on proactive policy interventions for addressing future global heat hazard, FPOP will enable future-oriented assessments of a wide range of environmental hazards, e.g. hurricanes, droughts, and flooding.
Identification of bio-oil chemical compounds from pyrolysis process of oil palm empty fruit bunches
Authors: Majid Z A N M , Rahmawati L , Riyani C
Published: August 2022

Indonesia is the highest CPO producer globally, but CPO production also produces waste. The highest waste in CPO production is empty fruit bunch (EFB) (±58.3%). EFB is biomass waste that has the highest lignocellulose compound. Lignocellulose compound could utilize by conversion with physical, chemical, and biological degradation. Pyrolysis is one of the physical methods to degrade the lignocellulose compound. This research aimed to determine bioactive compounds produced from EFB pyrolysis. The analysis of chemical compound degradation from pyrolysis used gas chromatography and mass spectroscopy (GC-MS) method. The results of GC-MS from liquid smoke showed that were three highest concentrations, including acetic acid at 48.28%, phenol (CAS) at 9.10%, 2-furancarboxaldehyde (CAS) furfural at 4.44%.
Heat treatment to increase self-bonding property of binderless boards manufactured from rice straw
Authors: Kurokochi Y , Saito Y
Published: August 2022

Rice straw is an abundant agricultural waste globally, but it has not been used effectively. Binderless boards manufactured without synthetic resins are an environment-friendly material, and they are also a possible way to utilize rice straw. However, the presence of wax and silica on the surface of rice straw reduces the bonding ability. The study objective was to manufacture binderless boards from heat-treated rice straws and investigate the effect of heat treatment on the self-bonding properties. Heat treatment was performed on chips or powder from rice straw (≤50 mm, 1 mm) at 200 °C, 1.5 MPa for 0–60 min. Heat-treated rice straw (≤50 mm, 1 mm, 150 µm) was hot-pressed to form binderless boards at 220 °C and 5 MPa for 10 min. The resulting board was 300 × 300 × 5 mm, 0.8 g/cm3. The mechanical and physical properties of the boards were tested according to the JIS A5905-2014 standards. Electron microscopy (SEM), particle-size distribution, and gas chromatography-mass spectrometry (GC-MS) analyses were conducted to examine the effect of heat treatment. The results showed that heat treatment for more than 40 min increased internal bonding because of physical and chemical changes in the rice straw.
Enhancement of bioethanol production from tofu waste by engineered simultaneous saccharification and fermentation (SSF) using co-culture of mold and yeast
Authors: Rahayuningsih M , Febrianti F , Syamsu K
Published: August 2022

Tofu waste is a potential raw material for producing bioethanol since it has 52,82 % carbohydrate content, among which 35,12 % is starch. Indonesia has approximately 315 tofu business units that produce 2,6 million tons of tofu per year, so the availability of tofu waste is abundant, and its current use is only for feed. The use of starch as the raw material of bioethanol needs two steps, namely saccharification and fermentation. Application of Simultaneous Saccharification and Fermentation (SSF) technique may reduce the processing time of bioethanol production from starchy materials. The SSF involves co-culture, namely aerobic molds (Aspergillus niger) that hydrolyze starch into sugar and facultative anaerobic yeasts (Saccharomyces cerevisiae) that ferment sugar into ethanol. The objectives of the study were to obtain a production technique of bioethanol from the starch of tofu waste, which has more productive and higher yield through Engineered SSF/ESSF (stop aeration at a particular time) technique using co-culture of mold and yeast and to compare it with Conventional SSF/CSSF (complete aeration) technique. ESSF produced bioethanol at 11.39 g/L with the product yield per substrate used (Yp/s) of 0.36 g/g. In comparison, CSSF produced bioethanol at 7.69 g/L with the Yp/s of 0.23 g/g. ESSF technology has been proved to be more productive and efficient than CSSF since it can increase bioethanol production and Yp/s of 1.5 and 1.6 times, respectively. The study results also prove that the starch from tofu waste can be utilized as media for bioethanol production.
Quality changes of natural dye powder from red leaf amaranth (Alternanthera amoena Voss) during storage
Authors: Permatasari N A , Sari F
Published: August 2022

Redleaf amaranth (Alternanthera amoena Voss) can be used as a natural dye because it has high anthocyanin content and is stable on low pH. This research aimed to observe the quality changes of natural dye powder from red leaf amaranth during storage and estimate its shelf life. The production of natural dye powder using a solvent of distilled water+5% citric acid and 15% maltodextrin then dried using a Vacuum Dryer at 60°C temperature for 1 hour. The powder was packed in PP plastic and stored at various temperatures (28, 45, 55 °C). The results showed that the natural dye powder at the beginning of the storage has 4.66% moisture content, 8% yield, 14.43 mg vitamin C/100 g materials, 94.48% solubility, 14.9% total titrated acid, 62.10 mg total anthocyanin/100 g materials and colour at 46.97 °Hue value (red). The higher the storage temperature, the greater the degradation of colour and total anthocyanin. The moisture content of the dye powder increases during storage. The shelf life of natural dye powder at 28°C, 45°C, and 55°C storage temperatures are 97 days, 41 days, and 25 days, respectively. Natural dye powder stored at 28°C has a longer shelf-life than those stored at 45°C and 55°C.