bluuebunny/crossref_metadata_2025 huggingface dataset:
Research and evaluation of the measurement uncertainty with the two-dimensional optical calibration plate
Authors: Hu Chang’an , Kong Linghui , Ouyang Hongmei , Luo Shutong , Lv Fei , Yang Li
Published: January 2021

As a portable standard, two-dimensional optical calibration plate is playing an increasingly important role in precision industry measurement. Therefore, it is of great scientific significance and obvious socioeconomic benefits to carry out the research of comparator. This paper was based on rich experience with the institute in the field of the geometric measurement technology for a long time, the measurement uncertainty of the optical calibration plate was studied, and the measurement uncertainty of the instrument has been researched. The measurement uncertainty of the error of the calibration plate’s setting and marking value was U= (0.14+ 0.015L) m k=2 L: mm.
Parallel Computing for Numerical Analysis of a Fan Assembly Subjected to a SPH Bird
Authors: Li Junjie , Lou Yunfeng , Yu Gaoyuan , Jin Xianlong
Published: January 2021

Smoothed Particle Hydrodynamics (SPH) is widely adopted to predict bird strike events. To improve the parallel computing efficiency of the SPH approach, parallel computing was performed on the process of a bird striking the fan assembly. Since the cube-shaped domains aligned along the coordinate axes that are inherent in the decomposition algorithm may result in low computational efficiency, the effect of customized data partitioning on the efficiency is investigated. The results show that customized decompositions can minimize communication between processors and ensure the load balance during the simulation process. Besides, distributed computing with domain decompositions can present reasonable predictions at soft-impact damage, achieving consistent results within a range of less than 7% of the reference data derived from shared memory computing.
Decision support system for customers during availability of trade credit financing with different pricing situations
Authors: Shaikh Ali Akbar , Das Subhash Chandra , Bhunia Asoke Kumar , Sarkar Biswajit
Published: January 2021

This study introduces an inventory system with a non-instantaneous deteriorating product with credit facility and variable demand depending on the selling price. Two different selling prices are considered in the deterioration and non-deterioration periods. Shortages are partially backlogged and dependent on the length of the customers’ waiting time upto the arrival of fresh lot. Alternative trade-credit policy is applied herein, and several cases, sub-cases and situations are investigated. The corresponding optimization problems of different cases, sub-cases and situations are solved using an interval-oriented multi-section technique with the help of interval mathematics and interval order relations. A numerical example with three different credit periods is studied and solved to validate the said problem. Also, two different case studies are investigated. Then to investigate the effect of changes of several system parameters on the optimal policy, post optimality analyses are performed.
Deep state in the bandgap and photoluminescence of Zn1−xMnxO
Authors: Sokolov V. I. , Gruzdev N. B. , Churmanov V. N. , Menshenin V. V. , Emelchenko G. A.
Published: January 2021

The impurity absorption in Zn1−xMnxO is formed by dipole allowed p-s transitions from deep antibonding p-d hybrid (pdh) state to the conduction band. In this paper, photoluminescence of Zn1−xMnxO single crystals was investigated in the temperature range of 7–340 K at laser excitation with the energy of 3.06 eV. Intensive photoluminescence band was observed in the energy region of 2.40–1.6 eV with the maximum at the energy of 2.17 eV. The energy of the impurity center ionization 2.35 eV was determined in this paper. The analysis of photoluminescence band form, and also close coincidence of its headline and impurity band edge allow us to interprete this band as a result of radiative dipole allowed s-p transitions from the conduction band to impurity pdh level.
Comment on: “Quantum aspects of a moving magnetic quadrupole moment interacting with an electric field” [J. Math. Phys. 56, 062107 (2015)]
Authors: Fernández Francisco M.
Published: January 2021

We analyze the results obtained for the quantum dynamics of a moving particle with a magnetic quadrupole moment interacting with electric and magnetic fields. We argue that there are no bound states contrary to what the authors state. It is shown that the proposed method is unsuitable for obtaining all the bound states and that the existence of allowed oscillator frequencies is an artifact of the approach.
Counterstreaming ions at the inner pole of a magnetically shielded Hall thruster
Authors: Huang Wensheng , Kamhawi Hani
Published: January 2021

During development testing of a 12.5 kW magnetically shielded Hall thruster, direct evidence of counterstreaming ions eroding the pole covers was found. One stream of ions appears to originate from the discharge channel while the other stream appears to originate from the centrally mounted cathode. Velocity distribution measurement indicates that each stream impacts the poles of the thruster at high oblique angles of incidence. While the average energy of each stream was in the tens of eV, the energy distributions contained high-energy tails that can be a major contributor to erosion. Starting with the physical picture of high oblique angle bombardment, predictions of change in erosion behavior over time are in good agreement with pole cover erosion measurements taken during wear testing. The new evidence points to a need to study these ions that are traditionally considered “low-energy” ions and the role they play in the erosion of the poles of magnetically shielded Hall thrusters.
Development of in situ optical spectroscopy with high temporal resolution in an aberration-corrected transmission electron microscope
Authors: Liu Chang , Ma Chaojie , Xu Jinjing , Qiao Ruixi , Sun Huacong , Li Xiaomin , Xu Zhi , Gao Peng , Wang Enge , Liu Kaihui , Bai Xuedong
Published: January 2021

Exploring the corresponding relation between structural and physical properties of materials at the atomic scale remains the fundamental problem in science. With the development of the aberration-corrected transmission electron microscopy (AC-TEM) and the ultrafast optical spectroscopy technique, sub-angstrom-scale spatial resolution and femtosecond-scale temporal resolution can be achieved, respectively. However, the attempt to combine both their advantages is still a great challenge. Here, we develop in situ optical spectroscopy with high temporal resolution in AC-TEM by utilizing a self-designed and manufactured TEM specimen holder, which has the capacity of sub-angstrom-scale spatial resolution and femtosecond-scale temporal resolution. The key and unique design of our apparatus is the use of the fiber bundle, which enables the delivery of focused pulse beams into TEM and collection of optical response simultaneously. The generated focused spot has a size less than 2 µm and can be scanned in plane with an area larger than 75 × 75 µm2. Most importantly, the positive group-velocity dispersion caused by glass fiber is compensated by a pair of diffraction gratings, thus resulting in the generation of pulse beams with a pulse width of about 300 fs (@ 3 mW) in TEM. The in situ experiment, observing the atomic structure of CdSe/ZnS quantum dots in AC-TEM and obtaining the photoluminescence lifetime (∼4.3 ns) in the meantime, has been realized. Further ultrafast optical spectroscopy with femtosecond-scale temporal resolution could be performed in TEM by utilizing this apparatus.
SQUID-arrays coupled to on-chip integrated thin-film superconducting input coils operating coherently
Authors: Chesca Boris , John Daniel , Cantor Robin
Published: January 2021

Recently, Superconducting Quantum Interference Device (SQUID) arrays operating in a coherent voltage-modulation state at 77 K showed a flux-noise 10 times lower than that of single-SQUIDs at similar temperatures. To exploit the flux-noise superiority of SQUID-arrays in applications, however, it is essential to preserve the coherent state, while the magnetic field to be measured, Bz, is highly inhomogeneous along the array as being generated by thin film integrated superconducting input coils or flux-transformers located in close proximity. Indeed, the flux coupled to each individual SQUID may vary significantly along the array, leading to a rapid degradation in the coherency. Here, we present several solutions to avoid that based on a methodology we developed to assess the efficiency of signal coupling to SQUID-arrays while maintaining a highly coherent state. As a proof of concept, we applied it to highly integrated YBa2Cu3O7 800/770 SQUID-arrays inductively coupled to on-chip integrated thin film superconducting input coils. Each SQUID in the array is directly coupled to two individual flux focusers, leading to an increase in the effective area for which we derived an analytical formula. Consequently, we achieved SQUID-like voltage oscillation amplitudes above 10 mV in the temperature range (75–83) K, leading to a magnetic flux noise of 0.2 μΦ0/Hz1/2, consistent with an ultra-enhanced coherent operation reached. For the strongest coupling scheme implemented experimentally, a current white noise of SI1/2 = 32 pA/Hz1/2 was measured. This scheme can be used as the input coil of a flux-transformer, resulting in a SQUID-array-based magnetometer with an estimated field sensitivity of 13 fT/Hz1/2.
Effect of liquid depth on dynamics and collapse of large cavities generated by standing waves
Authors: Raja D. Krishna , Das S. P.
Published: January 2021

The effect of fluid depth on the collapse of large cavities generated by over-driven axisymmetric gravity waves in a 10 cm diameter cylindrical container has been studied. At a large fluid depth in a viscous glycerine–water solution, the collapse of the cavities is inertia dominant at the initial phase with the time-dependent cavity radius (rm) obeying rm ∝ τ1/2; τ = t − t0 being the time remaining for collapse, with t0 being the time at collapse. However, enhanced damping at a low liquid depth turns the late stage of the transition into the viscous regime (rm ∝ τ) at some critical depth beyond which a singular collapse (transition from non-pinch-off and pinch-off collapse) is impossible. At a shallow depth, the change in cavity radius follows a flip of the power law, i.e., rm ∝ τ at the initial stage of collapse followed by a transition to rm ∝ τ1/2, suggesting a viscous–inertial transition. For fluids with relatively lower viscosity but similar surface tension, here water, a smoother cavity with damped parasitic waves at a small liquid depth collapses at a smaller radius. The surface jet velocity due to the collapse of the cavity monotonically decreases with the decrease in the depth, whereas in the case of water, it increases with the depth reaching a maximum at a critical depth followed by a decrease again. The self-similarity, exhibited by the cavity up to the critical depth, is lost due to the axial movement restriction by the bottom wall.
Transient processes during an initial stage of breakdown in saline solution
Authors: Korolev Y. D. , Shemyakin I. A. , Kasyanov V. S. , Geyman V. G. , Landl N. V. , Bolotov A. V.
Published: January 2021

This paper deals with the investigation of the discharge in the solution of 0.9% NaCl in water for the conditions, when the voltage at the gap is in a vicinity of the so-called critical voltage at which the discharge in a thin vapor layer at the surface of active electrode appears. In the experiments, the critical voltage is at a level of (180–200) V. Most of the data correspond to powering the discharge by the bipolar voltage pulses of 5 s duration. The main attention is centered on the nonsteady (transient) processes and on the forms of the discharge operation. For the voltage pulses of negative polarity, when the metal electrode is the cathode, the discharge is sustained in the glow regime with the occasional glow-to-spark transitions. At the positive polarity of the voltage, the surface of liquid inside the vapor layer plays a role of cathode in the gas-discharge gap. In these conditions, the process of the glow-to-spark transition is suppressed and the discharge is sustained in the glow regime.
Computational inverse design for ultra-compact single-piece metalenses free of chromatic and angular aberration
Authors: Lin Zin , Roques-Carmes Charles , Christiansen Rasmus E. , Soljačić Marin , Johnson Steven G.
Published: January 2021

We present full-Maxwell topology-optimization design of a single-piece multilayer metalens, about 10 wavelengths λ in thickness, which simultaneously focuses over a 60° angular range and a 23% spectral bandwidth without suffering chromatic or angular aberration, a “plan-achromat.” At all angles and frequencies, it achieves diffraction-limited focusing (Strehl ratio >0.8) and an absolute focusing efficiency of >50%. Both 2D and 3D axisymmetric designs are presented, optimized over ∼105 degrees of freedom. We also demonstrate shortening the lens-to-sensor distance while producing the same image as for a longer “virtual” focal length and maintaining plan-achromaticity. These proof-of-concept designs demonstrate the ultra-compact multifunctionality that can be achieved by exploiting the full wave physics of subwavelength designs and motivate future work on design and fabrication of multilayer metaoptics.
Deep-learning potential method to simulate shear viscosity of liquid aluminum at high temperature and high pressure by molecular dynamics
Authors: Cheng Yuqing , Wang Han , Wang Shuaichuang , Gao Xingyu , Li Qiong , Fang Jun , Song Hongzhou , Chu Weidong , Zhang Gongmu , Song Haifeng , Liu Haifeng
Published: January 2021

The shear viscosity of matter and efficient simulating methods in a wide range of temperatures and densities are desirable. In this study, we present the deep-learning many-body potential (the deep potential) method to reduce the computational cost of simulations for the viscosity of liquid aluminum at high temperature and high pressure with accurate results. Viscosities for densities of 2.35 g/cm3, 2.7 g/cm3, 3.5 g/cm3, and 4.27 g/cm3 and temperatures from melting points to about 50 000 K are calculated. The results agree well with the experiment data at a pressure near 1 bar and are consistent with the simulation of first-principles at high pressure and high temperature. We reveal the behavior of the shear viscosity of liquid Al at a range where the current experimental results do not exist. Based on the available experimental data and newly generated simulation data, we propose a modified Enskog–Dymond theory, which can analytically calculate the viscosity of Al at this range. This research is helpful for numerous potential applications.
A two-dimensional array of single-hole quantum dots
Authors: van Riggelen F. , Hendrickx N. W. , Lawrie W. I. L. , Russ M. , Sammak A. , Scappucci G. , Veldhorst M.
Published: January 2021

Quantum dots fabricated using methods compatible with semiconductor manufacturing are promising for quantum information processing. In order to fully utilize the potential of this platform, scaling quantum dot arrays along two dimensions is a key step. Here, we demonstrate a two-dimensional quantum dot array where each quantum dot is tuned to single-charge occupancy, verified by simultaneous measurements using two integrated radio frequency charge sensors. We achieve this by using planar germanium quantum dots with low disorder and a small effective mass, allowing the incorporation of dedicated barrier gates to control the coupling of the quantum dots. We measure the hole charge filling spectrum and show that we can tune single-hole quantum dots from isolated quantum dots to strongly exchange coupled quantum dots. These results motivate the use of planar germanium quantum dots as building blocks for quantum simulation and computation.
Chirality control of the spin structure in monoaxial helimagnets by charge current
Authors: Ohe Jun-ichiro , Onose Yoshinori
Published: January 2021

Chirality control of the spin structure in monoaxial helimagnets by using charge current is theoretically investigated. The classical J1−J2 Heisenberg model has two degenerate helical states that are characterized by the chirality. In a recent experiment, it has been shown that the chirality of the spin structure can be controlled by applying a charge current during the field-decreasing process [Jiang et al., Nat. Commun. 11, 1601 (2020)]. We reproduced this experiment by numerical calculations based on the Landau–Lifshitz–Gilbert equation with the spin-transfer torque. We show that the damping torque and spin-transfer torque are responsible for the controllability. In addition, we theoretically propose more convenient forms of chirality control: instantaneous switching of chirality and zero-field control by using a ferromagnet junction. Such improved controllability may pave the way to spintronics based on the chirality degree of freedom.
Surface corrugated laminates as elastic grating couplers: Splitting of SV- and P-waves by selective diffraction
Authors: Chaplain G. J. , Craster R. V.
Published: January 2021

The phenomenon of selective diffraction is extended to in-plane elastic waves, and we design surface corrugated periodic laminates that incorporate crystal momentum transfer, which, due to the rich physics embedded within the vector elastic system, results in frequency, angle, and wave-type selective diffraction. The resulting devices are elastic grating couplers, with additional capabilities as compared to analogous scalar electromagnetic couplers, in that the elastic couplers possess the ability to split and independently redirect, through selective negative refraction, the two body waves present in the vector elastic system: P- (compressional) and SV- (shear-vertical) elastic waves. The design paradigm, and interpretation, is aided by obtaining isofrequency contours via a non-dimensionalized transfer matrix method.
Low defect density and small I−V curve hysteresis in NiO/
β
-Ga2O3 pn diode with a high PFOM of 0.65 GW/cm2
Authors: Hao Weibing , He Qiming , Zhou Kai , Xu Guangwei , Xiong Wenhao , Zhou Xuanze , Jian Guangzhong , Chen Chen , Zhao Xiaolong , Long Shibing
Published: January 2021

In this Letter, we report a high-performance NiO/β-Ga2O3 pn heterojunction diode with an optimized interface by annealing. The electrical characteristics of the pn diode without annealing (PND) and with annealing (APND) are studied systematically. The APND device has a lower specific on-resistance of 4.1 mΩ cm2, compared to that of the PND, 5.4 mΩ cm2. Moreover, for the APND, a high breakdown voltage of 1630 V with lower leakage current is achieved, which is 730 V higher than that of the PND. The enhanced electrical performance of the APND leads to a record high power figure of merit of 0.65 GW/cm2 in Ga2O3-based pn diodes, which is among the best reported results in Ga2O3 power devices. In addition, the interface trap density of the diode decreases from 1.04 × 1012 to 1.33 × 1011 eV−1 cm−2 after annealing, contributing to much lower hysteresis. Simultaneously, the ideality factor n for the APND is steady at elevated temperatures due to the stable interface. The results of C−V characteristics reveal the bulk defects inside the nickel oxide film grown by sputtering, which are calculated by high- and low-frequency capacitance methods. X-ray photoelectron spectroscopy of NiO illustrates the reasons for the changes in the concentration of holes and defects in the film before and after annealing. This work paves the way for further improving the performance of Ga2O3 diode via interface engineering.
Mixed focused-acoustic-vortices generated by an artificial structure plate engraved with discrete rectangular holes
Authors: Li Xin-Rui , Jia Yu-Rou , Luo Yan-Chun , Yao Jie , Wu Da-Jian
Published: January 2021

Recently, considerable attention has been paid to acoustic vortices (AVs) due to their increasing demands for practical applications. Conventional AV generators usually realize the AV with only one topological charge (TC), namely, carrying one orbital angular momentum. In this work, we demonstrate that mixed focused acoustic vortices (FAVs) with two TCs can be achieved via an artificial structure plate engraved with discrete rectangular holes (ASP-RHs). It is found that the performance of the mixed FAVs is highly dependent on the degeneracy of the ASP-RH. By modulating the number and distribution of RHs on the ASP, the mixed FAVs with different TCs can be generated. Finally, we experimentally confirm the generation of the mixed FAVs by the well-designed ASP-RH. The mixed FAVs may provide more opportunities for applications in particle manipulation and acoustic communication.
Spin-memory loss induced by bulk spin–orbit coupling at ferromagnet/heavy-metal interfaces
Authors: Lim Mijin , Lee Hyun-Woo
Published: January 2021

A spin current through a ferromagnet/heavy-metal interface may shrink due to the spin-flip at the interface, resulting in the spin-memory loss. Here, we propose a mechanism of the spin-memory loss. In contrast to other mechanisms based on interfacial spin–orbit coupling, our mechanism is based on the bulk spin–orbit coupling in a heavy metal. We demonstrate that the bulk spin–orbit coupling induces the entanglement between the spin and orbital degrees of freedom and this spin-orbital entanglement can give rise to sizable spin-flip at the interface even when the interfacial spin–orbit coupling is weak. Our mechanism emphasizes crucial roles of the atomic orbital degree of freedom and induces the strong spin-memory loss near band crossing points between bands of different orbital characters.
Core loss analysis of soft magnetic composites considering the inter-particle eddy current loss
Authors: Yang Yiming , Wang Youhua , Wu Shipu , Liu Chengcheng , Chen Long
Published: January 2021

Soft magnetic composite (SMC) is composed of ferromagnetic particles surrounded by electrical insulation layer. During the manufacturing process, the electric insulation layer may be destroyed and thus the eddy current will be induced, which makes it difficult to calculate the accurate eddy current loss. In this paper, the inter-particle eddy current loss is calculated at the macro-scale by modeling the actual sample and using the measured conductivity of the sample, moreover intra-particle eddy current loss is calculated by modeling single particle of SMC base on the existing model. Then, under different particle sizes and frequencies, the influence of skin effect on the calculation of eddy current loss is analyzed. Finally, to verify the proposed model, the iron losses of two SMC materials are calculated and they are compared with measured results. It can be seen that when the inter-particle eddy current loss has been considered, then the core loss of SMC will be agreed very well with the measurement results, thus the proposed model can be used for the actual core loss calculation for the electrical machine or other electromagnetic device with SMC cores.
Ruminal microbiota is associated with feed-efficiency phenotype of fattening bulls fed high-concentrate diets
Authors: Costa-Roura S. , Villalba D. , Blanco M. , Casasús I. , Balcells J. , Seradj A. R.
Published: January 2021

Abstract Context Improving feed efficiency in livestock production is of great importance to reduce feeding costs. Aims To examine the relationship between ruminal microbiota and variation in feed efficiency in beef cattle fed concentrate-based diets. Methods Residual feed intake of 389 fattening bulls, supplied with corn-based concentrate and forage ad libitum, was used to estimate animals’ feed efficiency. Faeces and ruminal fluid samples, from 48 bulls chosen at random, were collected to estimate their forage intake and to determine their apparent digestibility, ruminal fermentation and microbiota. Those animals with extreme values of feed efficiency (high-efficiency (HE, n = 12) and low-efficiency (LE, n = 13)) were subjected to further comparisons. Alpha biodiversity was calculated on the basis of the normalised sequence data. Beta diversity was approached through performing a canonical correspondence analysis based on log-transformed sequence data. Genera differential abundance was tested with an ANOVA-like differential expression analysis and genera interactions were determined applying the sparse correlations for compositional data technique. Key results No differences in dry matter intake were found between the two categories of feed efficiency (P = 0.699); however, HE animals had higher apparent digestibility of dry matter (P = 0.002), organic matter (P = 0.003) and crude protein (P = 0.043). The concentration of volatile fatty acids was unaffected by feed efficiency (P = 0.676) but butyrate proportion increased with time in LE animals (P = 0.047). Ruminal microbiota was different between HE and LE animals (P = 0.022); both α biodiversity and genera network connectance increased with time in LE bulls (P = 0.005 for Shannon index and P = 0.020 for Simpson index), which suggests that LE animals hosted a more robust ruminal microbiota. Certain genera usually related to high energy loss through methane production were found to establish more connections with other genera in LE animals’ rumen than in HE ones. Microbiota function capability suggested that methane metabolism was decreased in HE finishing bulls. Conclusions Rumen microbiota was associated with feed efficiency phenotypes in fattening bulls fed concentrate-based diets. Implications The possible trade-off between feed efficiency and robustness of ruminal microbiota should be taken into account for the optimisation of cattle production, especially in systems with intrinsic characteristics that may constitute a disturbance to rumen microbial community.
Prioritisation of candidate genes in QTL regions for seed germination and early seedling growth in bread wheat (Triticum aestivum) under salt-stress conditions
Authors: Rezaei Elham , Hervan Eslam Majidi , Azadi Amin , Etminan Alireza , Ramshini Hossein
Published: January 2021

Salinity and drought are major abiotic stresses affecting wheat (Triticum aestivum L.) production throughout the world, and discovery of loci for traits affecting yield under salinity may lead to the breeding for salt-tolerant plants. In the present study, 186 F10 recombinant inbred line (RIL) populations were evaluated under salt-stress conditions in order to identify main-effect and epistatic-effect quantitative trait loci (QTLs) for 15 traits in wheat during the germination and early-seedling stages. In total, 61 main-effect QTLs on 15 chromosomes and 21 epistatic interactions on 12 chromosomes were detected through composite interval mapping (CIM) and a mixed-model-based CIM method. Two major QTLs for primary-leaf fresh weight and coleoptile fresh weight were detected on chromosome (or linkage group) 5B2 and 2D, respectively, which contributed ~44% and 43% of the phenotypic variance. Additionally, 12 QTL clusters including different traits were detected on 1A1, 3A, 4A, 2B1, 3B, 5B1 and 2D1. Candidate genes were identified within QTL regions and gene ontology (GO) enrichment analysis was performed. In total, 9134 candidate genes were grouped into 274 GO terms (including 79 GO terms involved in the ‘biological process’ category). These genes directly or indirectly play a vital role such as lipid localisation, biological regulation, fatty acid biosynthetic process, cellular process, DNA conformation change, translational elongation, carbohydrate metabolic process, Fe ion homeostasis, hydrogen peroxide metabolic process, and pigment biosynthetic process at the germination and early-seedling stages under salt-stress conditions.
Cancer recurrence and lethality are enabled by enhanced survival and reversible cell cycle arrest of polyaneuploid cells
Authors: Pienta K. J. , Hammarlund E. U. , Brown J. S. , Amend S. R. , Axelrod R. M.
Published: January 2021

We present a unifying theory to explain cancer recurrence, therapeutic resistance, and lethality. The basis of this theory is the formation of simultaneously polyploid and aneuploid cancer cells, polyaneuploid cancer cells (PACCs), that avoid the toxic effects of systemic therapy by entering a state of cell cycle arrest. The theory is independent of which of the classically associated oncogenic mutations have already occurred. PACCs have been generally disregarded as senescent or dying cells. Our theory states that therapeutic resistance is driven by PACC formation that is enabled by accessing a polyploid program that allows an aneuploid cancer cell to double its genomic content, followed by entry into a nondividing cell state to protect DNA integrity and ensure cell survival. Upon removal of stress, e.g., chemotherapy, PACCs undergo depolyploidization and generate resistant progeny that make up the bulk of cancer cells within a tumor.
Speed breeding: a space inspired technology
Authors: Vijaya Amalraj Mohanlal , Rajendran Raj Nirmal , Ramalingasamy Ralshiya , Jayakumar Jayanthi Sneka
Published: January 2021

Speed breeding technology reduces the breeding cycle and fastens crop research by producing many generations within a short period of time. In this technology, plants are exposed to an extended light and reduced night time for rapid generation advancement. For instance, wheat crop can be cultivated for 2–3 generations per year under normal glass house conditions but employing speed breeding, it can be cultivated up to 6 generations per year. Speed breeding approach is inspired by NASA experiments conducted on a space mission where wheat crops were grown inside small chambers exposed to a continuous source of light. The basic principal underlying this technique is optimization of photosynthetic activity to promote rapid growth of crops, whereas the extended photoperiod with a short dark period supports functional expression of circadian clock genes. The circadian clock coordinates the biological processes with changing external environment and acts as an internal timekeeper. Under controlled environment of growth chambers, speed breeding can accelerate plant development phase which will be useful for variety development and crop research purposes including phenotyping, mutant studies and transformation. In the process of variety development, conventional breeding approaches take 7–10 years for crossing and inbreeding to develop genetically stable lines, while speed breeding takes only 2 years for crossing and inbreeding. Moreover, this technology can speed up genomic selection and can be integrated with other advanced techniques like genome editing and high throughput genotyping.
Resonance ionisation spectrometry measurement of atomic calcium Rydberg isotope shifts
Authors: Wells Stephen R , Miyabe Masabumi , Iwata Yoshihiro , Hasegawa Shuichi
Published: January 2021

Rydberg levels in atomic calcium are of interest due to their use in highly isotope selective multiple-step resonance ionisation spectrometry, and also for nuclear physics investigations, but gaps remain in the data for higher lying levels in calcium isotopes other than

Ca

40

. We report novel isotope shift data on four isotopes of calcium (

Ca

42

,

Ca

43

,

Ca

44

,

Ca

48

), relative to the majority abundance isotope

Ca

40

, in six Rydberg transitions for each P (n = 25–30) and F (n = 23–28) angular momentum quantum number designated series.
Dual-wavelength multilevel diffractive lenses for near-infrared imaging
Authors: Yang Gensen , Zhang Fei , Pu Mingbo , Li Xiong , Ma Xiaoliang , Guo Yinghui , Luo Xiangang
Published: January 2021

Optical imaging systems play an extremely important role for humans in exploring the world, but the existence of chromatic aberration greatly reduces the imaging ability. Conventional optical systems require the combination of multiple lenses to reduce chromatic aberration, but such a solution is not conducive to the miniaturization and weight reduction of the optical system. In this paper, we design dual-wavelength multilevel diffractive lenses that focus pairs of wavelengths on the same focal plane, using a modified direct-binary-search algorithm to maximize the focusing efficiency. The simulated focusing efficiencies are 72% (92%) and 79% (92%) at the wavelength of 1.064 μm and 1.55 μm, respectively, for the two-dimensional (one-dimensional) ones. Through this approach, the results presented here suggest good focusing performance at two wavelengths, providing a new opportunity for various applications in dual-wavelength imaging systems and lightweight collimators.
Transition-metal adatoms on 2D-GaAs: a route to chiral magnetic 2D materials by design
Authors: González-García A , López-Pérez W , González-Hernández R , Bacaksiz C , Šabani D , Milošević M V , Peeters F M
Published: January 2021

Using relativistic density-functional calculations, we examine the magneto-crystalline anisotropy and exchange properties of transition-metal atoms adsorbed on 2D-GaAs. We show that single Mn and Mo atom (Co and Os) strongly bind on 2D-GaAs, and induce local out-of-plane (in-plane) magnetic anisotropy. When a pair of TM atoms is adsorbed on 2D-GaAs in a close range from each other, magnetisation properties change (become tunable) with respect to concentrations and ordering of the adatoms. In all cases, we reveal presence of strong Dzyaloshinskii–Moriya interaction. These results indicate novel pathways towards two-dimensional chiral magnetic materials by design, tailored for desired applications in magneto-electronics.
Stress effect on segregation and ordering in Pt–Ag nanoalloys
Authors: Front Alexis , Mottet Christine
Published: January 2021

We performed a theoretical study of the chemical ordering and surface segregation of Pt–Ag nanoalloys in the range of size from 976 to 9879 atoms (3.12 to 6.76 nm). We used an original many-body potential able to stabilize the L11 ordered phase at equiconcentration leading to a strong silver surface segregation. Based on a recent experimental study where nanoparticles up to 2.5 nm have been characterized by high transmission electron microscopy with the L11 ordered phase in the core and a silver surface shell, we predict in our model via Monte Carlo simulations that the lower energy configuration is more complicated with a three-shell alternance of Ag/Pt/Ag from the surface surrounding the L11 ordered phase in the core. The stress analysis demonstrates that this structure softens the local stress distribution inside the nanoparticle which contributes to reduce the internal energy.
A novel solder joint diagnosis algorithm using differential geometry approach in high-density flexible integrated circuit substrates
Authors: Zeng Yong , Hu Yueming , Huang Dan
Published: January 2021

To provide a system with high-density solder joint 3D information acquisition and improve the comprehensive performance of automatic optical inspection systems, a novel diagnosis system for solder joints of high-density flexible integrated circuit substrates is proposed in this paper. The differential geometry principle is introduced to analyze the appearance identity of solder joints, and the diagnosis is handled as a pattern-recognition problem with the Frenet frame-matching approach. First, a high-precision 3D information-acquisition system constituted of two CCD digital cameras, each with a microscope and a three-color LED illumination, is developed. Second, a discrete estimation scheme based on the differential geometry theory is proposed to achieve curvature measurement, and then the shape of the solder joints is characterized by the crest line representation method. Finally, the classification strategy is to establish different models of solder joint types and make a decision based on a set of the predefined diagnosis rules. By inspecting various types of solder joints and comparing with other typical algorithms, the performance of the proposed system is evaluated. The experiment results indicate that the proposed algorithm has advantages of fast inspection speed, low misjudgment rate, which is reduced to 2.2%, and detailed classification.
A level set approach to simulate grain growth with an evolving population of second phase particles
Authors: Alvarado Karen , Florez Sebastian , Flipon Baptiste , Bozzolo Nathalie , Bernacki Marc
Published: January 2021

In numerous polycrystalline materials, grain size is controlled by second phase particles (SPPs) that hinder the grain boundaries (GBs) by pinning mechanisms. The Smith–Zener pinning (SZP) model describes the physical interaction between SPPs and GBs. Both of them can evolve when applying a heat treatment to the material. As industrial forging processes involve hot deformation steps near the solvus temperature, it is thus of prime importance to characterize the evolution of the SPPs due to their impact on the final microstructure, notably on the grain size. The level set (LS) method is classically used to describe the influence of SPPs on grain growth (GG) by considering the simulated particles as inert and represented by static holes in the used finite element (FE) mesh. A new formalism to model GG mechanism under the influence of the SZP phenomenon, able to take into account evolving particles is proposed. It involves the representation of SPPs by a LS function and a particular numerical treatment around the grain interfaces encountering SPP, making possible the modelling of SPPs evolution without altering the undergoing pinning pressure. Validation and comparison of the new method regarding previous FE-LS formulation in 2D and 3D simulations and an application on GG under the influence of dissolving particles are described.
Interfacial dislocation network in precipitation strengthened alloys during creep: a discrete dislocation dynamics (DDD) study in three dimensions
Authors: Jogi Tushar , Bhattacharya Saswata
Published: January 2021

Ni-base superalloys show an intricate network of dislocations around γ′ precipitates during high-temperature low-to-intermediate stress creep. With an aim to understand the formation of this interfacial dislocation network on the surfaces of unsheared, cuboidal γ′ precipitates, we perform three-dimensional discrete dislocation dynamics simulations at constant stress in a model system containing superellipsoidal inclusions. The exponents of the superellipsoid are adjusted to fit the cuboidal shape of γ′. We use a fault-energy-based back-force model to describe interactions between dislocations and structurally inhomogeneous inclusions. The model incorporates climb of edge dislocation segments on non-glissile planes through a modified dislocation mobility law for face-centred cubic crystals. Athermal repulsive intersection cross-slip is considered for the screw segments. We systematically show the evolution of dislocation network as a function of applied stress, inter-particle spacing, and ratio of glide-to-climb mobility. We scale the simulation box and the inclusions by the same factor in order to keep the volume fraction of inclusions constant in all cases. Although the dislocation density increases with the increase in applied stress as well as inter-particle spacing, the onset of steady-state in all cases is marked by a constant mobile-to-immobile dislocation density (ρ
m/ρ
im) ratio. For the range of stresses and inter-particle spacings considered in this study, the steady-state ρ
m/ρ
im remains nearly the same. Our simulations indicate a power-law behaviour where the stress exponent n ≈ 4 suggests dislocation climb to be the rate-controlling mechanism. The simulated morphological features of the dislocation network formed on the surfaces of the inclusions at steady-state (e.g., hexagonal nets due to dislocation reactions) are similar to those observed experimentally in single-crystalline superalloys crept at high temperatures and low stresses. Moreover, we obtain a relationship between length scale associated with dislocation density and applied stress.
Enforcing local equilibrium of point defects near sinks in object kinetic Monte Carlo simulations
Authors: Jourdan T
Published: January 2021

A model for the emission of point defects by point defect sinks is proposed for object kinetic Monte Carlo simulations. Local equilibrium of point defects in the vicinity of sinks is ensured by construction, even if elastic interactions are taken into account for the diffusion of point defects. The emission of vacancies by dislocation segments is treated in detail and validated numerically. The model is then used to simulate the annealing of a vacancy Frank loop in a system containing surfaces. Results are in overall good agreement with analytical formulas, which are based on the approximation of instantaneous equilibration of the vacancy field during the loop evolution process. For small loops the shrinkage is so rapid that this quasi-static approximation is no more valid.
Metal–insulator transition in single crystalline ZnO nanowires
Authors: Milano G , D’Ortenzi L , Bejtka K , Ciubini B , Porro S , Boarino L , Ricciardi C
Published: January 2021

In this work, we report on the metal–insulator transition and electronic transport properties of single crystalline ZnO nanowires synthetized by means of Chemical Vapor Deposition. After evaluating the effect of adsorbed species on transport properties, the thermally activated conduction mechanism was investigated by temperature-dependent measurements in the range 81.7–250 K revealing that the electronic transport mechanism in these nanostructures is in good agreement with the presence of two thermally activated conduction channels. More importantly, it was observed that the electrical properties of ZnO NWs can be tuned from semiconducting to metallic-like as a function of temperature with a metal-to-insulator transition (MIT) observed at a critical temperature above room temperature (T
c ∼ 365 K). Charge density and mobility were investigated by means of field effect measurements in NW field-effect transistor configuration. Results evidenced that the peculiar electronic transport properties of ZnO NWs are related to the high intrinsic n-type doping of these nanostructures that is responsible, at room temperature, of a charge carrier density that lays just below the critical concentration for the MIT. This work shows that native defects, Coulomb interactions and surface states influenced by adsorbed species can significantly influence charge transport in NWs.
Core–shell structured monodisperse carbon-rich SiO1.31C1.46H0.81 ceramic spheres as anodes for high-capacity lithium-ion batteries
Authors: Zeng Ying , He Zhiyan , Li Mingqi
Published: January 2021

SiOC ceramic material is a promising anode material for lithium-ion batteries. However, due to its intrinsically low electronic conductivity, it often suffers from a much lower specific capacity than the theoretical value, poor rate capability and serious potential hysteresis. In this paper, we report a core–shell structured monodisperse carbon-rich SiO1.31C1.46H0.81 submicron ceramic sphere with a free carbon content of 13.7 wt%, which is synthesized by directly annealing polysiloxane spheres derived from vinyltrimethoxysilane without adding external carbon resources. The SiO1.31C1.46H0.81 sphere has a unique microstructure, the core of which is organically assembled by large amounts of SiO1.31C1.46H0.81 primary particles of less than 20 nm and coated by a shell of 20–50 nm. As anodes for lithium-ion batteries, it presents much higher reversible capacity, initial Coulomb efficiency (ICE) and rate performance than the SiOC-based ceramic materials reported in the literature to date. At 100 mA g−1, its first reversible capacity and ICE reach ∼1107 mAh g−1 and 78.2%, respectively. At 1600 mA g−1, its stable discharge capacity is still as high as 610 mAh g−1. The excellent electrochemical performance is attributed to the moderate composition, spherical morphology and unique microstructure of the synthesized material.
Glycyrrhetinic acid remodels the tumor microenvironment and synergizes with doxorubicin for breast cancer treatment in a murine model
Authors: Tang Mingxiu , Yang Mengjia , He Kaiyong , Li Ran , Chen Xiaojie , Wang Yaowen , Zhang Xueqiong , Qiu Tong
Published: January 2021

We aimed to combine glycyrrhetinic acid with doxorubicin to prepare, characterize and evaluate a drug delivery nano-system with REDOX sensitivity for the treatment of breast cancer. M-DOX-GA NPs prepared by nano sedimentation were spherical, with a particle size of 181 nm. And the maximum encapsulation efficiency and drug loading in M-DOX-GA NPs were 89.28% and 18.22%, respectively. Cytotoxicity and cellular uptake experiments of nanoparticles to KC cells, Cal-27 cells and 4T1 cells were studied by the CCK-8 method. The result indicated that M-DOX-GA NPs could accurately release the drug into the tumor cells, thus achieving the targeted release of the drug. Comparing the survival rate of the above three cells, it was found that M-DOX-GA NPs had a good tumor selectivity and had a more significant therapeutic effect on breast cancer. A 4T1-bearing mouse model was established, and the tumor inhibition rate was 77.37% after injection of nanoparticle solution for 14 d. Normal tissue H&E stained sections and TUNEL assay were verified M-DOX-GA NPs have excellent tumor suppressive effect, and can efficiently reduce the toxic side effects on normal organisms, and effectively avoided 4T1 cells metastasis. Immunofluorescence detection and Western-blot analysis figured a decline in both CUGBP1 and α-SMA, which verifying the TME remodeling induced by glycyrrhetinic acid. Collectively, the combination of doxorubicin and glycyrrhetinic acid is an effective and safe strategy for remodeling fibrotic TME by improving the therapeutic outcome for breast cancer.
Algodoo for online education: impulse and momentum activities
Authors: Çoban Atakan
Published: January 2021

During the periods of sudden transition to online education, the opportunity to make applications that might attract students’ attention to the course has decreased even more. Although this deficiency tried to be eliminated with videos and simulations, it was not possible to ensure the active participation of students in some cases. In this study, the Algodoo program, which can increase the efficiency of the teaching environment by ensuring active participation of students in online lessons and the applications that can be done about impulse and momentum, are explained in detail. A total of six different applications were carried out, one related to the subject of impulse, one related to the momentum, two related to the relationship between impulse and momentum change, and two related to momentum conservation. At the same time, while developing these applications, the adjustments made on the simulation and the reasons are explained in detail. In this way, both the introduction of the program and the sample application suggestion were presented. The values obtained as a result of the applications were calculated and compared both theoretically and on simulation in different ways. As a result, it has been observed that the values have internal consistency with each other and are also compatible with theoretical calculations. The Algodoo program, which allows many interactive applications and can be downloaded for free, is a program that can be used both in lecturing and evaluation processes in physics lessons during the online education process.
The magnetic field in the axis of an elliptic loop current
Authors: Romero-Abad David
Published: January 2021

The calculation of the magnetic field produced by a loop current using the Biot–Savart law is a very typical exercise in introductory university physics. However, the cases studied are limited, in most textbooks, only the circular arrangement is treated. In this article, we calculate the magnetic field of an elliptical loop current along an axis that passes through its centre. This calculation uses physical concepts and mathematical techniques that would be accessible to an average freshman student.