bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective strain manipulation of the antiferromagnetic state of polycrystalline NiO
Authors: Barra A. , Ross A. , Gomonay O. , Baldrati L. , Chavez A. , Lebrun R. , Schneider J. D. , Shirazi P. , Wang Q. , Sinova J. , Carman G. P. , Kläui M.
Published: April 2021

As a candidate material for applications such as magnetic memory, polycrystalline antiferromagnets offer the same robustness to external magnetic fields, THz spin dynamics, and lack of stray fields as their single crystalline counterparts, but without the limitation of epitaxial growth and lattice matched substrates. Here, we first report the detection of the average Néel vector orientation in polycrystalline NiO via spin Hall magnetoresistance (SMR). Second, by applying strain through a piezo-electric substrate, we reduce the critical magnetic field required to reach a saturation of the SMR signal, indicating a change of the anisotropy. Our results are consistent with polycrystalline NiO exhibiting a positive sign of the in-plane magnetostriction. This method of anisotropy-tuning offers an energy efficient, on-chip alternative to manipulate a polycrystalline antiferromagnet's magnetic state.
Direct current microplasma formation around microstructure arrays
Authors: Fu Yangyang , Wang Huihui , Zheng Bocong , Zhang Peng , Fan Qi Hua , Wang Xinxin , Verboncoeur John P.
Published: April 2021

We demonstrate the formation and transition behaviors of a microplasma around microstructure arrays at different gas pressures via two-dimensional particle-in-cell/Monte Carlo collision simulations. It is found that the microdischarge occurs outside the cathode microcavities at the lowest pressure and starts penetrating the microcavities with a curved sheath edge as the pressure increases. At higher pressure, coupled periodic microhollow cathode discharges (MHCDs) are formed inside the microcavities. Further increasing the gas pressure results in the disappearance of the MHCDs, and the dominant discharge shifts outside of the microcavity, locating above the protrusion tips. The effect of the space charge shielding on the discharge and the conditions for MHCD formation are discussed. The macroscopic discharge parameter scalings with the gas pressure and the electron kinetics are also examined. The results are helpful for deeply understanding the microplasma formation with nonplanar electrodes, which inform the scaling, design, and optimization of microplasma array devices across a wide range of pressure regimes in practical applications.
Determination of the temperature coefficient of resistance from micro four-point probe measurements
Authors: Marangoni Thomas A. , Guralnik Benny , Borup Kasper A. , Hansen Ole , Petersen Dirch H.
Published: April 2021

Current characterization methods of the temperature coefficient of resistance (TCR) of thin films are often limited to slow macroscale measurements, which further require a direct determination of temperature. In this work, we present an innovative application of micro four-point probe (M4PP) sensing, which enables a fast, non-destructive, local measurement of Joule heating effects that can be translated into TCR of the thin film. Analytical expressions for the four-point resistance response to local heating, and ultimately the temperature profile during an M4PP measurement, are derived and validated against finite element models. The method is successfully demonstrated on three metal thin films (7, 10, and 16 nm platinum deposited on fused silica). We evaluate TCR using two different electrode configurations, resulting in unique temperature fields, and observe a measurement repeatability of <2% for each configuration. Furthermore, the M4PP-TCR method shows only a minor (∼18%) systematic offset relative to reference TCR measurements obtained via an independent physical property measurement system. Our results demonstrate a new technique for characterizing TCR on the micrometer scale, adequately backed by theory. The measurement time is just a few seconds and could allow for thin film TCR mapping or in-line process monitoring on test structures.
Negative effect of cations out-diffusion and auto-doping on switching mechanisms of transparent memristor devices employing ZnO/ITO heterostructure
Authors: Simanjuntak Firman Mangasa , Chandrasekaran Sridhar , Panda Debashis , Rajasekaran Sailesh , Rullyani Cut , Madhaiyan Govindasamy , Prodromakis Themistoklis , Tseng Tseung-Yuen
Published: April 2021

An excessive unintentional out-diffused In atom into the switching layer is a potential threat to the switching stability of memristor devices having indium tin oxide (ITO) as the electrode. We suggest that the physical factor (bombardment of Ar ions and bombardment-induced localized heat during ZnO deposition) and chemical factor (bonding dissociation energy, point defects, and bond length of atoms) are responsible for promoting the out-diffusion. The In atom acts as dopant in the ZnO lattice that degenerates the ZnO insulative behavior. Furthermore, the In ions take part in the conduction mechanism where they may compete with other mobile species to form and rupture the filament, and hence, deteriorate the switching performance. We propose a facile UV/O3 (UVO) treatment to mitigate such damaging effects. The device fabricated on the UVO-treated ITO substrate exhibits significant switching parameter improvement than that of the device manufactured on untreated ITO. This work delivers an insight into the damaging effect of out-diffusion and auto-doping processes on the reliability of memristor devices.
Large thermoelectric power factor in wafer-scale free-standing single-walled carbon nanotube films
Authors: Horike S. , Kuwahara Y. , Wei Q. , Kirihara K. , Mukaida M. , Saito T.
Published: April 2021

Single-walled carbon nanotubes (SWCNTs) have the potential for application in thermoelectric energy generators owing to their advantages, such as good charge-carrier transport properties, mechanical flexibility and robustness, and tunability of polarity. However, the fabrication of SWCNTs still remains a problem due to its complexity and high cost. In this paper, we propose an approach for the direct formation of free-standing SWCNT films from as-grown SWCNT mats without any dispersion or separation processes. We used this approach to develop high-performance SWCNT-based thermoelectric leg materials. The as-grown SWCNT mats were synthesized by an enhanced direct injection pyrolytic synthesis (eDIPS) method. The selectivity of the tube diameter for the eDIPS method clarified the dependence of the thermoelectric performance of the free-standing SWCNT films on the tube diameter. The Seebeck coefficients and thermal conductivities were found to correlate with the tube diameter and agreed with the theoretical predictions. Owing to the dispersion-free film formation, our SWCNT films afforded large thermoelectric power factors. In particular, a power factor of 350 μW/(m K2) was obtained for the mean tube diameter of 1.7 nm without any semiconductor extraction or doping treatments. Our approach allowed the fabrication of thermoelectric legs with an arbitrary size; thus, it offers a useful strategy for the simpler, cheaper, and low-waste manufacturing of high-performance organic thermoelectric devices.
An investigation of the interface and bulk contributions to the magneto-optic activity in Co/Pt multi-layered thin films
Authors: Ece Demirer Figen , Lavrijsen Reinoud , Koopmans Bert
Published: April 2021

We report an experimental study that focuses on the magneto-optic interaction between light and perpendicularly magnetized ferromagnetic thin-film multilayers. In this study, samples containing multiple Co/Pt interfaces are measured via the polar magneto-optic Kerr effect. Thanks to a sample set with a continuous Co thickness variation and single and double Co-layered samples, interface and bulk contributions to the magneto-optic activity are separately determined. Kerr rotation and ellipticity signals are recorded as a function of the Co thickness. The results are analyzed via a transfer matrix method that accounts for the standard optical and magneto-optic effects in multi-layered thin-films. Bulk magneto-optic contribution of Co (QCo,bulk) that is in accordance with the literature is consistently determined despite the use of thin-films. Interfacial Co (QCo,int.) and magnetized Pt (QPt) contributions are presented in terms of two models. Interface phenomena of the large spin–orbit coupling between Co and Pt and the proximity induced magnetization in Pt layer are represented in the models. The strength of interfacial magneto-optic activity is interpreted as an indicator of the relative interface quality among the samples.
Kinetics analysis of the electron transfer from nano-TiO2 to O2 through on-line absorptions and theoretical modeling
Authors: Liu Baoshun , Wu Zhizhou , Li Liuyang
Published: April 2021

On-line optical absorptions were monitored under steady light illuminations to study the electron relaxations happening through the transfer from nano-TiO2 to O2, which are found to be slow and dispersive. A quasi-equilibrium (QE) theory and Monte Carlo simulations are developed to model the electron transfer, and they give good fittings to the early stage electron relaxations (over 70%). It is shown that the electron QE population at traps is kept during the whole electron relaxations. The slow kinetics is attributed to both the low probability (ptr) for an electron transferring to an O2 from a trap and the multi-trapping transport. The dispersive feature is ascribed to the dynamic decrease in the quasi-Fermi level (EF). The electron transfer rate constants just after the termination of light illuminations are taken out from the QE model fittings to analyze the relaxation kinetics. It is found that O2 amounts mainly affect the electron transfer by changing ptr; light intensities and temperatures mainly affect the electron transfer by changing the multi-trapping transport. The difference between the conduction band edge and the EF is the thermal barrier of the electron transfer from TiO2 to O2. The apparent activation energy (Eapp) of the electron transfer, determined from the absorption decays measured at different temperatures, is smaller than the real thermal barrier because of the decrease of EF with temperatures. The disagreement between the simulations and the later stage relaxations is not caused by the none-QE electron distribution at deep traps, and additional deep traps with a different distribution should also contribute to the electron relaxations.
Coupling of torsion and OH-stretching in tert-butyl hydroperoxide. I. The cold and warm first OH-stretching overtone spectrum
Authors: Hansen Anne S. , Huchmala Rachel M. , Vogt Emil , Boyer Mark A. , Bhagde Trisha , Vansco Michael F. , Jensen Casper V. , Kjærsgaard Alexander , Kjaergaard Henrik G. , McCoy Anne B. , Lester Marsha I.
Published: April 2021

The infrared (IR) spectrum of tert-butyl hydroperoxide (TBHP) in the region of the first OH-stretching overtone has been observed under jet-cooled and thermal (300 K, 3 Torr) conditions at ∼7017 cm−1. The jet-cooled spectrum is recorded by IR multiphoton excitation with UV laser-induced fluorescence detection of OH radical products, while direct IR absorption is utilized under thermal conditions. Prior spectroscopic studies of TBHP and other hydroperoxides have shown that the OH-stretch and XOOH (X = H or C) torsion vibrations are strongly coupled, resulting in a double well potential associated with the torsional motion about the OO bond that is different for each of the OH-stretching vibrational states. A low barrier between the wells on the torsional potential results in tunneling split energy levels, which leads to four distinct transitions associated with excitation of the coupled OH-stretch-torsion states. In order to interpret the experimental results, two theoretical models are used that include the OH-stretch-torsion coupling in TBHP. Both methods are utilized to compute the vibrational transitions associated with the coupled OH-stretch-torsion states of TBHP, revealing the underlying transitions that compose the experimentally observed features. A comparison between theory and experiment illustrates the necessity for treatments that include OH-stretch and COOH torsion in order to unravel the spectral features observed in the first OH-stretching overtone region of TBHP.
Coupling of torsion and OH-stretching in tert-butyl hydroperoxide. II. The OH-stretching fundamental and overtone spectra
Authors: Vogt Emil , Huchmala Rachel M. , Jensen Casper V. , Boyer Mark A. , Wallberg Jens , Hansen Anne S. , Kjærsgaard Alexander , Lester Marsha I. , McCoy Anne B. , Kjaergaard Henrik G.
Published: April 2021

The vibrational spectra of gas phase tert-butyl hydroperoxide have been recorded in the OH-stretching fundamental and overtone regions (ΔvOH = 1–5) at room temperature using conventional Fourier transform infrared (ΔvOH = 1–3) and cavity ring-down (ΔvOH = 4–5) spectroscopy. In hydroperoxides, the OH-stretching and COOH torsion vibrations are strongly coupled. The double-well nature of the COOH torsion potential leads to tunneling splitting of the energy levels and, combined with the low frequency of the torsional vibration, results in spectra in the OH-stretching regions with multiple vibrational transitions. In each of the OH-stretching regions, both an OH-stretching and a stretch–torsion combination feature are observed, and we show direct evidence for the tunneling splitting in the OH-stretching fundamental region. We have developed two complementary vibrational models to describe the spectra of the OH-stretching regions, a reaction path model and a reduced dimensional local mode model, both of which describe the features of the vibrational spectra well. We also explore the torsional dependence of the OH-stretching transition dipole moment and show that a Franck–Condon treatment fails to capture the intensity in the region of the stretch–torsion combination features. The accuracy of the Franck–Condon treatment of these features improves with increasing ΔvOH.
Design and simulation of silicon detector cells with spiral ring electrode structures
Authors: Li Xinqing , Liu Manwen , Li Zheng
Published: April 2021

Traditional pixel detectors are neatly arranged rectangular or square electrodes that cover almost the entire surface. Large electrode areas lead to high capacitance, and capacitance is the primary factor affecting detector noise. A large noise signal will reduce detector detection performance and the system S/N ratio. We have designed a spiral ring electrode silicon detector cell with n-type silicon bulk and systematically studied its electrical properties, including electric potential distribution, electric field distribution, electron concentration distribution, leakage current, full depletion voltage, and detector capacitance. It has been verified that the spiral ring electrode silicon detector has a smaller capacitance than the traditional detector and a smaller depletion voltage compared with the previously designed structures such as the inner circle broom-shaped structure. At the same time, high position resolution pixel detectors can be made by the array of these detector cells.
High-efficiency generation of harmonics in polythiophene
Authors: Vasenin N.T. , Ivanenko A.V. , Klement’ev V.M. , Kulik L.V. , Nevostruev D.A. , Nyushkov B.N. , Trashkeev S.I. , Khomyakov M.N.
Published: April 2021

High-efficiency harmonic generation is observed in a semiconducting polymer RR-P3HT [regioregular poly(3-hexylthiophene)], which exhibits a high nonlinear susceptibility [χ
(2) > 10−6 m V−1] under pumping by a pulsed fibre laser. The harmonic generation efficiency in RR-P3HT is comparable or higher than that observed for liquid crystals, which are used in reference experiments to estimate the susceptibility [the quadratic susceptibility of a nematic liquid crystal NLC 1289 is χ
(2) ≈ 2 × 10−6 m V−1]. No generation is observed in polythiophene with a random structure, RRa-P3HT [regiorandom poly(3-hexylthiophene)], at the same pump power. It is experimentally demonstrated that a necessary condition for generating the second and third harmonics in a polymer, along with a high pump power density, is the presence of a large power density gradient (exceeding 1013 W m−3). Based on a preliminary theoretical analysis, we can suggest that the quadrupole mechanism, which is a consequence of the regularity of RR-P3HT structure in the thin near-wall layer, may contribute significantly to the nonlinear radiation conversion in semiconducting polymers.
Stable Q-switched mode-locking of an in-band pumped Ho : Y2O3 ceramic laser at 2117 nm
Authors: Shen Yajie , Li Enhao , Wang Jun , Tang Dingyuan , Shen Deyuan
Published: April 2021

We have demonstrated stable Q-switched mode-locked operation of an in-band pumped Ho : Y2O3 ceramic laser at 2117 nm by using an InGaAs/GaAs-based saturable absorber. An average output power of 330 mW is reached for 2.7 W of absorbed pump power with stable mode-locked pulses having a 98.9-MHz repetition rate and 100% modulation depth embedded inside Q-switched envelopes of ∼1.7-μs duration. The duration of the mode-locked pulses is estimated to be less than 1.5 ns.
Luminescent properties of a ZnO whisker array as a scintillation detector material
Authors: Tarasov A.P. , Venevtsev I.D. , Muslimov A.E. , Zadorozhnaya L.A. , Rodnyi P.A. , Kanevsky V.M.
Published: April 2021

We have studied luminescent properties of a ZnO whisker array, a promising crystalline material for scintillation detectors, capable of ensuring a fast and strong response and a short afterglow time. Measurements have been performed under X-ray and UV optical excitation. We present a comparative analysis of spectral features of the near-band-edge emission of the whisker array at low (∼80 K) and room temperatures in relation to the excitation method.
Excess broadband noise at equal intensities in the interferometer arms
Authors: Gelikonov V.M. , Romashov V.N. , Gelikonov G.V.
Published: April 2021

We report a theoretical and experimental study of the excess photocurrent noise in the detection of low-coherence radiation caused by the beats of the random components of the optical spectrum at equal intensities in the interferometer arms. It is shown that, in this case, the spectral density of photocurrent fluctuations is

times higher than when detecting radiation without interference. This result makes it possible to clarify the value of the limiting level of the total fundamental noise of low-coherence radiation during interference. Excess noise cannot be completely subtracted in balanced detection.
Possibilities of measuring the exhaled air composition using Raman spectroscopy
Authors: Petrov D.V. , Matrosov I.I. , Kostenko M.A.
Published: April 2021

A Raman spectrometer for gaseous media with a detection limit at a level of 100 ppb is developed. The results of its experimental approval on exhaled air samples from healthy people confirmed the possibility of monitoring the concentrations of a number of hydrocarbon compounds and 13CO2. The ways of further development of this analytical method are outlined.
Mass spectrometry of volatile organic compounds ionised by laser plasma radiation
Authors: Bukharina A.B. , Pento A.V. , Simanovsky Ya.O. , Nikiforov S.M.
Published: April 2021

Vacuum UV radiation from laser-induced plasma is used to ionise volatile organic compounds (VOCs) released by living organisms during their mass spectrometric analysis at atmospheric pressure without sample preparation. It is shown that the probability of ionisation of organic compounds with different ionisation potentials and proton affinity at atmospheric pressure in the argon flow weakly depends on the compound parameters and can be 3.6 × 10−5 – 1.4 × 10−4. The VOC spectra of mouse and human biological fluids are obtained without sample preparation at room temperature of the sample. The possibility of using the proposed method for the diagnosis of pathological changes is demonstrated.
Enhancing the time contrast and power of femtosecond laser pulses by an optical wedge with cubic nonlinearity
Authors: Khazanov E.A.
Published: April 2021

A method is proposed for enhancing the time-domain contrast of femtosecond laser pulses under nonlinear pulse compression by means of spectrum broadening due to the self-phase modulation with a following reflection from chirped mirrors. The contrast increases because the radiation of the pedestal is blocked by a square screen arranged in a focal plane of a unit-magnification telescope, and the main pulse ‘bypasses’ the screen, because a wedge in front of the telescope declines the pulse to a large angle due to a cubic nonlinearity.
Spectroscopic comparison method for determining the electron temperature of high-temperature plasmas of heavy element
Authors: Shevelko A.P.
Published: April 2021

For further development of the comparison method, the X-ray spectra of laser plasmas of light (Si, S, Cl, K, Ca, Ti) and heavy (Mo, W) elements are studied. Plasma is produced by focusing nanosecond laser radiation (λ = 0.53 μm, E
L = 5 J, τ = 2 ns) onto massive solid targets. The spectra are recorded using two focusing crystal spectrometers in the wavelength range λ = 2 – 11 Å. A detailed analysis of H- and He-like ion spectra is performed to determine the dependence of the electron temperature (T
e = 500 – 800 eV) on the energy of laser pulses (E
L = 0.5 – 5 J). Recommendations are given for measuring T
e from the spectra of light elements with maximum accuracy. The comparison method is employed to estimate the electron temperature of the plasmas of heavy elements (Mo, W), whose X-ray spectra are complex in structure.
Theory of homotopes with applications to mutually unbiased bases, harmonic analysis on graphs, and perverse sheaves
Authors: Bondal A. I. , Zhdanovskiy I. Yu.
Published: April 2021

This paper is a survey of contemporary results and applications of the theory of homotopes. The notion of a well-tempered element of an associative algebra is introduced, and it is proved that the category of representations of the homotope constructed by a well-tempered element is the heart of a suitably glued-structure. The Hochschild and global dimensions of homotopes are calculated in the case of well-tempered elements. The homotopes constructed from generalized Laplace operators in Poincaré groupoids of graphs are studied. It is shown that they are quotients of Temperley–Lieb algebras of general graphs. The perverse sheaves on a punctured disc and on a 2-dimensional sphere with a double point are identified with representations of suitable homotopes. Relations of the theory to orthogonal decompositions of the Lie algebrasinto a sum of Cartan subalgebras, to classifications of configurations of lines, to mutually unbiased bases, to quantum protocols, and to generalized Hadamard matrices are discussed.

Bibliography: 56 titles.
The impact of multiple molecular and morphological data sets on the phylogenetic reconstruction of subtribe Neurachninae (Poaceae: Panicoideae: Paniceae)
Authors: Thompson E. J. , Fabillo Melodina
Published: April 2021

The taxonomy of Neurachninane has been unstable, with its member genera consisting of Ancistrachne, Calyptochloa, Cleistochloa, Dimorphochloa, Neurachne, Paraneurachne and Thyridolepis, changing since its original circumscription that comprised only the latter three genera. Recent studies on the phylogeny of Neurachninae have focused primarily on molecular data. We analysed the phylogeny of Neurachninae on the basis of molecular data from seven molecular loci (plastid markers: matK, ndhF, rbcL, rpl16, rpoC2 and trnLF, and ribosomal internal transcribed spacer, ITS) and morphological data from 104 morphological characters, including new taxonomically informative micromorphology of upper paleas. We devised an impact assessment scoring (IAS) protocol to aid selection of a tree for inferring the phylogeny of Neurachninae. Combining morphological and molecular data resulted in a well resolved phylogeny with the highest IAS value. Our findings support reinstatement of subtribe Neurachninae in its original sense, Neurachne muelleri and Dimorphochloa rigida. We show that Ancistrachne, Cleistochloa and Dimorphochloa are not monophyletic and Ancistrachne maidenii, Calyptochloa, Cleistochloa and Dimorphochloa form a new group, the cleistogamy group, united by having unique morphology associated with reproductive dimorphism.
Anaerobic gut fungi are an untapped reservoir of natural products
Authors: Swift Candice L. , Louie Katherine B. , Bowen Benjamin P. , Olson Heather M. , Purvine Samuel O. , Salamov Asaf , Mondo Stephen J. , Solomon Kevin V. , Wright Aaron T. , Northen Trent R. , Grigoriev Igor V. , Keller Nancy P. , O’Malley Michelle A.
Published: April 2021

Significance

Anaerobic gut fungi are important members of the gut microbiome of herbivores, yet they exist in small numbers relative to bacteria. Here, we show that these early-branching fungi produce a wealth of secondary metabolites (natural products) that may act to regulate the gut microbiome. We use an integrated 'omics'-based approach to classify the biosynthetic genes predicted from fungal genomes, determine transcriptionally active genes, and verify the presence of their enzymatic products. Our analysis reveals that anaerobic gut fungi are an untapped reservoir of bioactive compounds that could be harnessed for biotechnology.
Claviceps sorghi (sorghum ergot).
Authors:   USA, USDA-ARS
Published: April 2021

C. sorghi is a pathogen of Sorghum bicolor found only in India and Southeast Asia. The more widespread Claviceps africana is predominant even in India; C. sorghi appears to be marginalized in its restricted range. A significant difference in invasiveness is the relative production of inoculum that spreads plant-to-plant. C. sorghi produces few to no secondary conidia from macroconidia on infected florets, whereas C. africana produces large numbers of these airborne propagules. The macroconidia of C. sorghi may themselves be transported in honeydew by wind, rain-splash, insects or direct contact between plants, but these are more limited means. Fungal sclerotia and/or the sphacelia state may be carried among harvested seed, but the seed lots can be cleaned or treated with fungicides (Bandyopadhyay et al., 1996). Alternative hosts are pearl millet (Pennisetum glaucum), wild and weedy relatives of S. bicolor, and wild grasses.
Bemisia tabaci (MEAM1) (silverleaf whitefly).
Authors: Cuthbertson Andrew
Published: April 2021

The exact origin of the MEAM1 species of Bemisia tabaci, and the reasons why it became such an important pest are still not fully known. MEAM1 was first identified in the mid 1980s when it invaded the southern states of North America. Vast numbers of whiteflies were found to be infesting winter vegetable crops and consequently caused an estimated $500 million loss to the 1991 winter harvest in California. Investigations led to the assumption that the B biotype had spread to the USA on ornamental plants that were being transported around the world. Species such as poinsettia and gerbera were highlighted as probable hosts. During the 1990s MEAM1 was reported on every continent. Biological traits of MEAM1 implied that it had evolved within intensive agricultural regions with exposure to pesticides and modern cultural practices. These included an ability to feed and develop on a wide range of plant and crop species, a high level of fecundity and a predisposition to develop resistance to a wide range of pesticides. MEAM1 is also an effective vector of many different plant viruses which, in conjunction with its high level of polyphagy, make it extremely problematic within agricultural regions where crops may be susceptible to viruses acquired from indigenous plants. Despite B. tabaci being a tropical/sub-tropical whitefly species, MEAM1 is often transported on plant species to temperate regions of the world. Within these cooler regions, MEAM1 can survive within a protected environment and could feasibly spread virus diseases to new locations. It is for this reason that B. tabaci and members of its species complex, including MEAM1, are on EPPO A2 Alert list.
Hibiscus tiliaceus (coast cottonwood).
Authors: Pasiecznik Nick
Published: April 2021

H. tiliaceus is a medium-sized tree, normally 8-12 m tall (maximum 20 m) and stem to 50 cm dbh, with a dense crown and spreading branches. The bark is grey, smooth on young trees with brown, horizontally elongated lenticels; hard and thick with black, vertical fissures on larger trees. It has mucilaginous sap. The original natural distribution is obscure, but H. tiliaceus is now widely distributed in the sub-humid and humid tropics. It grows on coastal foreshores on sand or rock, behind mangrove communities that border brackish swamp forest and littoral subtropical rainforest on alluvial flats near the sea. It is infrequent on atolls. The timber is very fine and smooth, easy to work and takes a good polish. The leaves, bark and sap are used medicinally: leaves are wrapped around bone fractures; and fluid from young stems is used as an antiseptic for skin eruptions. The roots, flowers and young leaves are edible. The inner bark is used for its fibre to make twine, cordage for ropes, nets, basketware, fishing line and making skirts for ceremonial occasions. The bushy habit and decorative flowers make this species an attractive shade or ornamental tree for coastal gardens, although it is easily damaged by sea winds. It is a short-lived pioneer species that can become invasive and the extensive root system can become a problem to cultivation. It is thought to be a host for insect vectors of foliar decay disease of coconuts.
Lagerstroemia indica (Indian crape myrtle).
Authors: Rojas-Sandoval Julissa , Acevedo-Rodríguez Pedro
Published: April 2021

A datasheet on Lagerstroemia indica covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Physalis peruviana (Cape gooseberry).
Authors: Parker Chris
Published: April 2021

A datasheet on Physalis peruviana covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Ricinus communis (castor bean).
Authors: Rojas-Sandoval Julissa , Acevedo-Rodríguez Pedro
Published: April 2021

R. communis is probably native to Africa, although it has long been cultivated or is found growing wild throughout the tropics, subtropics and many warm temperate countries. It is a fast-growing shrub or small tree, to about 4 m high, and the seed oil has been utilized for at least 6000 years. The oil was used by Ancient Egyptians for illumination, but current uses are mainly in a wide range of industrial oils, for soaps, paints, varnishes, textile dyes, leather preservation and waterproofing for fabrics, or for preparation of medicinal products. Some forms are ornamental. Silkworms are fed on the leaves in Africa. Breeding for high oil content and frost tolerance should be further studied. The main disadvantage is that it can become weedy, and invade agricultural land.
Tibouchina urvilleana (princessflower).
Authors: Van De Witte Ymkje
Published: April 2021

A datasheet on Tibouchina urvilleana covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Voltage and cathode emission mechanisms of a magnetized, constricted, orbiting plasma in helium 6.7–850 Pa
Authors: Smith David J , Sommerer Timothy J , Lawler James E , Hitchon W Nicholas G
Published: April 2021

We present a semiquantitative description of several important properties of a magnetized cold-cathode plasma in helium over a wide pressure range 6.7–850 Pa. We focus on the ‘constricted orbiting’ mode where the plasma attaches to the cathode as a moving ‘dot’ and the voltage and rate of cathode erosion are both unusually low. We propose that the low plasma voltage and observed motion of the plasma adjacent to the cathode can be attributed to field emission as the source of electrons from the cathode, a process that is aided by the charging of an oxide film by ions. We find that the observed dependence of plasma voltage on pressure is consistent with the assumption that the axial electric field must increase in regions of strong crossed magnetic field to maintain current continuity.
An antipodal Vivaldi antenna array based on spoof surface plasmon polariton metamaterial with 5G mm Wave suppression
Authors: Zhu Shuangshuang , Liu Haiwen , Chen Zhijiao
Published: April 2021

An efficient method for achieving an antipodal Vivaldi antenna array with filtering performance based on spoof surface plasmon polariton (SSPP) metamaterial is proposed. The array is fed by a 1-to-8 power divider integrated with SSPP structures—named SSPP-I. The loaded SSPP-I obtains high cutoff frequency at 24 GHz. Both numerical simulations and measurements suggest the proposed array has a good performance in the desired frequency band from 22.01 to 24 GHz, in which the measured radiation patterns show a high gain level of 9.83 dBi on average, and the highest and lowest values are within 0.27 dBi of the average. The filtering performance, flat gain, low cost, and low profile have wide applications in the development of mmWave radio astronomy systems and can suppress the interference of 5 G mmWave to the system.
Yielding and resolidification of colloidal gels under constant stress
Authors: Moghimi Esmaeel , Schofield Andrew B , Petekidis George
Published: April 2021

We examine the macroscopic deformation of a colloidal depletion gel subjected to a step shear stress. Three regimes are identified depending on the magnitude of the applied stress: (i) for stresses below yield stress, the gel undergoes a weak creep in which the bulk deformation grows sublinearly with time similar to crystalline and amorphous solids. For stresses above yield stress, when the bulk deformation exceeds approximately the attraction range, the sublinear increase of deformation turns into a superlinear growth which signals the onset of non-linear rearrangements and yielding of the gel. However, the long-time creep after such superlinear growth shows two distinct behaviors: (ii) under strong stresses, a viscous flow is reached in which the strain increases linearly with time. This indicates a complete yielding and flow of the gel. In stark contrast, (iii) for weak stresses, the gel after yielding starts to resolidify. More homogenous gels that are produced through enhancement of either interparticle attraction strength or strain amplitude of the oscillatory preshear, resolidify gradually. In contrast, in gels that are more heterogeneous resolidification occurs abruptly. We also find that heterogenous gels produced by oscillatory preshear at intermediate strain amplitude yield in a two-step process. Finally, the characteristic time for the onset of delayed yielding is found to follow a two-step decrease with increasing stress. This is comprised of an exponential decrease at low stresses, during which bond reformation is decisive and resolidification is detected, and a power law decrease at higher stresses where bond breaking and particle rearrangements dominate.
Ab initio based interionic interactions in calcium aluminotitanate oxide melts: structure and diffusion
Authors: Jakse Noël , Alvares Cecilia M S , Pisch Alexander
Published: April 2021

Calcium aluminotitanate (CaO–Al2O3–TiO2) ternary oxides are of fundamental interest in Materials as well as Earth and environmental science, and a key system for several industrial applications. As their properties at the atomic scale are scarcely known, interionic interactions for the melts are built from a bottom up strategy consisting in fitting first only Al2O3, CaO and TiO2 single oxide compounds separately with a unified description of the oxygen charge and O–O interaction term. For this purpose, a mean-square difference minimization of the partial pair-correlation functions with respect to the ab initio reference was performed. The potentials for the ternary oxide are finally built straightforwardly by adding purely Coulomb terms for dissimilar cation–cation interactions without further fit. This general and unified approach is transferable and successfully describes the structural and diffusion properties of the three single oxides as well as the ternary melts simultaneously. A possible underlying structural mechanism at the origin of the diffusion evolution with TiO2 content is proposed based on the formation of Ti induced triply bonded oxygen.
Magnetic and magneto-thermal properties of ferrimagnetic alloys (Er1−x
Y
x
)(Co0.84Fe0.16)2 and their dependence on the orientations of resultant and sublattice magnetizations
Authors: Anikin M S , Tarasov E N , Kudrevatykh N V , Neznakhin D S , Semkin M A , Selezneva N V , Andreev S V , Zinin A V
Published: April 2021

In this paper structure, magnetic and magneto-thermal properties: magnetic entropy change (ΔS
m) and refrigeration capacity (q) of Er1–x
Y
x
(Co0.84Fe0.16)2 alloys (x = 0, 0.2, 0.4, 0.6, 0.8, 1) in magnetic fields up to 90 kOe in a temperature range of 5–360 K are investigated. An analysis of temperature dependences of magnetization (σ) and high-field susceptibility (χ
hf) showed that in these compounds, three different ferri- and a one ferromagnetic structures are consequently realized. Concentration dependences of magnetic moment at 5 K (μ
f.u.), Curie temperature (T
C), residual magnetization (σ
r) and coercivity (H
c) have been shown to have an extreme at intermediate Y concentration. The character of temperature dependence of magnetic entropy change (ΔS
m(T)) depends on the composition and originates from the type of magnetic structure of the compound and the mutual orientation of R- and 3d- element sublattices magnetization with respect to the resulting one. In compounds with x = 0.6 and x = 0.8 temperature regions with different signs of ΔS
m are observed, reflecting the change of dominating R- or 3d- sublattice in the resulting magnetization.
Research on a fault diagnosis method for rolling bearing based on improved multiscale range entropy and hierarchical prototype
Authors: Zheng Likang , He Ye , Chen Xiaoan
Published: April 2021

A novel fault diagnosis method based on improved multiscale range entropy and hierarchical prototype (HP) is proposed in this paper. Firstly, considering that range entropy cannot analyze the complexity of time series from multiple perspectives, the coarse-grained process is combined with range entropy. In addition, to make the coarse-grained process more comprehensive, the selection of its starting point is improved. Secondly, to extract more feature information, the dimension reduction of eigenvectors is carried out by using singular value decomposition. Finally, HP is trained with the eigenvectors and its performance is tested. To test the performance of the proposed fault diagnosis method, testing bearing vibration signals collected by sensors from Case Western Reserve University and Southeast University are used for experimental analysis in this paper, and the experimental results show high accuracy of the proposed fault diagnosis method. To verify the suitability of the improvement proposal, the superiority in feature extraction ability and the classification capability of the classifier, the proposed fault diagnosis method is compared with another seven fault diagnosis methods. The results show that the proposed fault diagnosis method has the highest fault diagnosis accuracy.
Plasmonic enhancement of photocurrent generation in two-dimensional heterostructure of WSe2/MoS2
Authors: Ghods Soheil , Esfandiar Ali
Published: April 2021

Enhancing the photoresponse of single-layered semiconductor materials is a challenge for high-performance photodetectors due to atomically thickness and limited quantum efficiency of these devices. Band engineering in heterostructure of transition metal chalcogenides (TMDs) can sort out part of this challenge. Here, we address this issue by utilizing the plasmonics phenomenon to enrich the optoelectronics property of the WSe2/MoS2 heterojunction and further enhancement of photoresponse. The introduced approach presents a contamination-free, tunable and efficient way to improve light interactions with heterojunction devices. The results showed a 3600-fold enhancement in photoresponsivity and a 46-fold increase in external quantum efficiency (549%) along with a fast photoresponse time (~2 μs) and light polarization dependence. This improvement may assign to multiple light scatterings by the Au nanoarrays and creation of strong local electrical fields (hot spots) at the interfaces of the gold nanoarrays and the TMDs heterostructure. The high-energy electrons (hot electrons) originating from hot spots surmount easily to conduction bands of heterojunction which is leading to a remarkable enhancement of photocurrent. The plasmons assisted photoresponse strategy can be easily matched with the semiconductor industry to boost the performance of optoelectronics devices for practical applications.
Preparation and mechanism research of bio-inspired dopamine decorated expanded graphite/silicone rubber composite with high thermal conductivity and excellent insulation
Authors: Liu Xingrong , Wu Wei , Liu Chao , Wang Yi , Chen Qiming , Cui Sufei
Published: April 2021

This study looked at the process of designing and synthesized expanded graphite (EG) and modifying it with bio-inspired dopamine (DOPA). This is a process used to improve the thermal conductivity and dielectric properties of methyl vinyl silicone rubber (VMQ). The results demonstrated that the EG-DOPA-VMQ composites acquired an exceptional thermal conductivity of 1.015 W mK−1 at the loading of 10 wt%, approximately 480% higher than that of pure silicone rubber (0.175 W mK−1). This enhancement is mainly attributed to the improved dispersion capability of EG-DOPA and the robust interfacial interaction between EG-DOPA-VMQ interfaces; specifically, this is the result when compared with pristine EG. Moreover, throughout this process, the composites maintained an excellent insulating property with a resistance of ≈1012 Ω · cm; this particular result was due to the DOPA deposited on EG surfaces because they acted as an insulating layer, inhibiting the electron transfer in composites. Overall, this work demonstrated that it could present a promising strategy for synchronized manufacturing of polymer composites with high thermal conductivity and insulating capability.
An anomaly detector as a clinical decision support system for parotid gland delineations
Authors: Papaconstadopoulos Pavlos , González Patrick , Carbaat Casper , Simões Rita , Beemster Herbert , Koetsveld Folkert , Remeijer Peter , Janssen Tomas
Published: April 2021

Purpose. Auto-contouring (AC) is rapidly becoming standard practice for OAR contouring. However, in clinical practice, clinicians still need to manually check and correct contours. Anomaly detection systems (ADS) can aid the clinical decision process by suggesting which structures require corrections or not, greatly enhancing the value of AC. The purpose of this work is to develop and evaluate a decision support system for detecting anomalies in the case of parotid gland delineations. Methods. Head and neck parotid gland delineations (1037 right, 1038 left), were retrieved from the Netherlands Cancer Institute (NKI) database. Morphological and image-based features were extracted from each patient’s CT and structure set. An isolation forest model was initially trained on 70% of the data, of which 10% had synthetically generated anomalies and validated on the remaining 30% of clinical data. The ADS was tested on an independent set of 250 patients (Normal: 174, Anomalies: 76) and on a clinical autocontouring software. Results. Applied to the validation set, the ADS system resulted in area under the curve (AUC) values of 0.93 and 0.94 for the parotid left and right respectively. Image features appeared more important than morphological, but using all features resulted marginally in the best model. Applied to the test set the ADS system reached an accuracy level of 0.83 and 0.81 for the parotid left and right respectively. The ADS was particularly sensitive to uniform expansions/contractions, misplacements, extra/missing slices and anisotropic over-contouring. Conclusion. Anomaly detection can serve as a powerful contour quality assurance tool, especially for cases of organ misplacement and over-contouring.
Smooth plasma etching of GeSn nanowires for gate-all-around field effect transistors
Authors: Eustache E , Mahjoub M A , Guerfi Y , Labau S , Aubin J , Hartmann J M , Bassani F , David S , Salem B
Published: April 2021

We report on the nanopatterning of horizontal and vertical germanium-tin (Ge1−x
Sn
x
or GeSn) nanowires by inductively coupled plasma reactive ion etching for gate-all-around field effect transistors. First, a chlorine based chemistry has been investigated and optimal conditions identified for GeSn 6% alloys. Then, plasma etching was optimized to etch high Sn content GeSn alloys (up to 15%) with a high anisotropy, smooth sidewalls and a high selectivity versus a hydrogen silsesquioxane hard mask. We have shown that, in order to obtain smooth surfaces after plasma etching, a HCl pre-treatment was mandatory to eliminate the native Sn and Ge oxides. This behavior was even more pronounced for high Sn contents. Finally, we succeeded in patterning 20 nm wide suspended beams from GeSn layers with Sn concentrations up to 15%.
Modeling and characterization for straight twisted polymer fiber actuators in blocked torsion: effect of radial thermal expansion
Authors: Takagi Kentaro , Iwai Hiroki , Oiwa Chihaya , Irisawa Toshihira , Shioya Masatoshi , Masuya Ken , Tahara Kenji , Sakurai Daichi , Watanabe Haruhiko , Asaka Kinji
Published: April 2021

This paper discusses a new model and experimental characterization for thermal responses of straight twisted polymer fiber (TPF) actuators in blocked torsion. The proposed model is derived from combining the fiber stiffness matrix with Shafer’s model of free torsion. The derived model predicts that the blocking torque increases as the initial twist increases. Although it is not widely recognized, the tension of a straight TPF decreases as the initial torsion increases, and this paper explains this fact. The proposed model predicts the decrease in tension by using Shafer’s kinematic model that considers the effect of radial thermal expansion. Experimental characterization and model verification are performed using nylon 6 (polyamide 6) fiber samples with ten different initial twists, ranging from weak to strong. The results indicate that as the initial twist increases, the torque increases and the tension decreases. The tension fluctuates with respect to time. The experimental results show that the shear modulus increases as the initial twist increases. The predictions of the proposed model are reasonably consistent with the experimental thermal responses of straight TPFs in blocked torsion when the constants obtained by experimental characterization are used.
Multiple plasmon-induced transparency with extra-high FOM based on a MIM waveguide composed of stubs
Authors: Hao Xiangxiang , Huo Yiping , He Qian , Guo Yiyuan , Niu Qiqiang , Cui Pengfei , Wang Yunyan , Song Meina
Published: April 2021

A plasmon structure based on a metal-insulator-metal (MIM) waveguide composed of three stubs (TSs) is proposed, and its transmission characteristics are studied numerically by the finite element method (FEM). The simulation results show that multiple plasmon-induced transparencies (PITs) with high transmission can be produced in the structure and can be tuned effectively. By adjusting the structure parameters, more high-order PITs with narrower window are generated. Furthermore, the proposed MIM waveguide is sensitive to the environment and the maximum values of refractive index sensitivity and figure of merit (FOM) are 1340 nm R−1IU−1 and 251/RIU, respectively. Multiple, adjustable and narrow PITs with high FOM can be induced in the proposed structure, which can be used in the fields of multi-channel filters, optical switches, storages, sensors, and so on.