bluuebunny/crossref_metadata_2025 huggingface dataset:
Hierarchical mining algorithm for high dimensional spatiotemporal big data based on association rules
Authors: Zhou Chunlei , Dong Xinwei , Ji Liang , Zhang Bijun , Xu Zhongping , Zhang Chengping
Published: May 2021

The traditional data mining algorithm focuses too much on a single dimension of data time or space, ignoring the association between time and space, which leads to a large amount of computation and low processing efficiency of the mining algorithm and makes it difficult to guarantee the final data mining effect. In response to the above problems, a hierarchical mining algorithm based on association rules for high-dimensional spatio-temporal big data is proposed. Based on the traditional association rules, after establishing the association rules of spatio-temporal data, the data to be mined are cleaned for redundancy. After selecting the local linear embedding algorithm to reduce the dimensionality of the data, a hierarchical mining strategy is developed to realize high-dimensional spatio-temporal big data mining by searching frequent predicates to form a spatio-temporal transaction database. The simulation experiment results verify that the algorithm has high complexity and can effectively reduce the processing volume, which can improve the processing efficiency by at least 56.26% compared with other algorithms.
A probabilistic view on the long-time behaviour of growth-fragmentation semigroups with bounded fragmentation rates
Authors: Cavalli Benedetta
Published: May 2021

The growth-fragmentation equation models systems of particles that grow and reproduce as time passes. An important question concerns the asymptotic behaviour of its solutions. Bertoin and Watson (2018) developed a probabilistic approach relying on the Feynman-Kac formula, that enabled them to answer to this question for sublinear growth rates. This assumption on the growth ensures that microscopic particles remain microscopic. In this work, we go further in the analysis, assuming bounded fragmentations and allowing arbitrarily small particles to reach macroscopic mass in finite time. We establish necessary and sufficient conditions on the coefficients of the equation that ensure Malthusian behaviour with exponential speed of convergence to the asymptotic profile. Furthermore, we provide an explicit expression of the latter.
Antibakterielle Prophylaxe in der Pädiatrischen
Hämatologie und Onkologie
Authors: Lehrnbecher Thomas , Simon Arne , Laws Hans-Jürgen , Agyeman Philipp KA , Ammann Roland A. , Attarbaschi Andishe , Berger Christoph , Bochennek Konrad , Neubert Jennifer , Poyer Fiona , Scheler Max , Strenger Volker , Vieth Simon , Zoellner Stefan , Groll Andreas H.
Published: May 2021

Kinder und Jugendliche, die durch eine Krebserkrankung und ihre Therapie
immunsupprimiert sind, haben ein hohes Risiko für potentiell
lebensbedrohliche Infektionen wie Bakteriämien durch Gram-positive und
Gram-negative Erreger. Aus diesem Grunde verabreichen einige Zentren diesen
Patienten eine antibakterielle Prophylaxe. Kürzlich wurden 2 Leitlinien
zur antibakteriellen Prophylaxe bei Kindern publiziert. Eine dieser Leitlinien
wurde durch eine internationale Expertengruppe aus Europa, Nord- und
Südamerika sowie Australien erstellt. Die andere Leitlinie wurde durch
eine rein europäische Gruppe im Rahmen der achten European Conference on
Infections in Leukaemia (ECIL-8) verfasst. In der vorliegenden
Übersichtsarbeit stellen die Arbeitsgruppen
„Infektionen“ der Gesellschaft für Pädiatrische
Onkologie und Hämatologie (GPOH) und „Fieber bei
Neutropenie“ der Deutschen Gesellschaft für Pädiatrische
Infektiologie (DGPI) die wichtigsten Daten von randomisierten Studien,
systematischen Reviews und Meta-Analysen zur antibiotischen Prophylaxe als auch
von Untersuchungen zur Resistenzentwicklung vor und diskutieren methodologische
Aspekte und jeweiligen Empfehlungen der beiden Leitlinien.
Upper Extremity Deep Vein Thrombosis: Current Knowledge and Future Directions
Authors: Yuen Hiu Lam Agnes , Tran Huyen , Chunilal Sanjeev
Published: May 2021

Upper extremity deep vein thrombosis (UEDVT) has been increasing in incidence due to the escalating use of central venous catheters such as peripherally inserted central catheters. UEDVT can be primary idiopathic or secondary to pacemaker leads, intravascular catheters or cancer. In comparison to conventional venous thromboembolism such as lower limb deep vein thrombosis or pulmonary embolism the risk factors, investigations, and management are not well defined. We review current evidence in primary and secondary UEDVT, highlighting areas in need of further research. We also explore the entity of venous thoracic outlet syndrome, which is said to be a risk factor for recurrent primary UEDVT and is the rationale behind surgical interventions.
Fast deuteron diagnostics using visible light spectra of 3He produced by deuteron–deuteron reaction in deuterium plasmas
Authors: Kimura K. , Matsuura H. , Kawamoto Y. , Oishi T. , Goto M. , Ogawa K. , Nishitani T. , Isobe M. , Osakabe M.
Published: May 2021

The fast deuteron (non-Maxwellian component) diagnostic method, which is based on the higher resolution optical spectroscopic measurement, has been developed as a powerful tool. Owing to a decrease in the D–H charge-exchange cross section, the diagnostic ability of conventional optical diagnostic methods should be improved for ∼MeV energy deuterons. Because the 3He–H charge-exchange cross section is much larger than that of D–H in the ∼MeV energy range, the visible light (VIS) spectrum of 3He produced by the dueteron–dueteron (DD) reaction may be a useful tool. Although the density of 3He is small because it is produced via the DD reaction, improvement of the emissivity of the VIS spectrum of 3He can be expected by using a high-energy beam. We evaluate the VIS spectrum of 3He for the cases when a fast deuteron tail is formed and not formed in the ITER-like beam injected deuterium plasma. Even when the beam energy is in the MeV energy range, a large change appears in the half width at half maximum of the VIS spectrum. The emissivity of the VIS spectrum of 3He and the emissivity of bremsstrahlung are compared, and the measurable VIS spectrum is obtained. It is shown that the VIS spectrum of 3He is a useful tool for the MeV beam deuteron tail diagnostics.
Langmuir probe array for the small angle slot divertor in DIII-D
Authors: Watkins J. G. , Wang H. Q. , Thomas D. , Murphy C. , Taussig D. , Ren J. , Chrobak C. , Guo H. Y.
Published: May 2021

The DIII-D small angle slot (SAS) divertor is designed for divertor physics studies with enhanced neutral confinement and special target geometries in a closed divertor. The closed nature of the SAS makes optical diagnostic measurements difficult, so a specially designed, multipurpose array of Langmuir probes has been implemented to study the plasma conditions in and around the slot. The probes are spaced to provide at least 2 mm resolution (shorter than the energy decay length) of the near scrape-off layer when mapped to the outer mid-plane. Due to space limitations at the bottom of the slot, a novel spring-loaded probe and tile design was developed to clamp several short rooftop probe tips and insulators to the cooled baseplate. Initial probe measurements revealed tile to tile edge shadowing, especially where magnetic field line surface angles were less than 1°. Additionally, it was found, using three Langmuir probes (at 90°, 180°, and 270°), that the strike point variation of ±5 mm radially around the torus was not well aligned with the circular slot geometry [Watkins et al., Nucl. Mater. Energy 18, 46 (2019)]. These issues were resolved by (1) designing tiles with all probes mounted near the tile center instead of near the edges and (2) aligning these new custom tiles to the measured strike point toroidal surface with a very accurate laser scanning alignment tool. Post-alignment Langmuir probe measurements and plasma behavior demonstrated close agreement at two separate toroidal locations that were 45° apart.
Quasi-stationarity of scalar turbulent mixing statistics in a non-symmetric case
Authors: Valiño Luis , Hierro Juan , Mustata Radu , Dopazo César
Published: May 2021

The existence of an asymptotic shape at large times of the probability density function (PDF) of a non-reacting scalar, mixed by a solenoidal turbulent velocity field and molecular diffusive transport, was investigated by Sinai and Yakhot [Y. G. Sinai and V. Yakhot, “Limiting probability distributions of a passive scalar in a random velocity field,” Phys. Rev. Lett. 63, 1962 (1989)]. The quasi-stationarity of the mixing statistics along the time evolution by Valiño et al. [“Quasistationary probability density functions in the turbulent mixing of a scalar field,” Phys. Rev. Lett. 72, 3518 (1994)] was an extension to symmetric scalar pdfs; analytic solutions for the scalar fluctuation dissipation rates, conditional upon the scalar value, and the pdf were obtained. This manuscript examines the generalization of the latter results to asymmetric scalar pdfs, further scrutinizes underlying mechanisms for a quasi-stationary statistics, and shows a Monte Carlo implementation which allows non-Gaussian relaxations to prescribed values of skweness and kurtosis.
Effect of the inclination angle on the transient melting dynamics and heat transfer of a phase change material
Authors: Madruga Santiago , Curbelo Jezabel
Published: May 2021

We report two-dimensional simulations and analytic results on the effect of the inclination on the transient heat transfer, flow, and melting dynamics of a phase change material within a square domain heated from one side. The liquid phase has Prandtl number Pr = 60.8, Stefan number Ste = 0.49, and Rayleigh numbers extend over eight orders of magnitude 0≤Ra≤6.6·108 for the largest geometry studied. The tilt determines the stability threshold of the base state. Above a critical inclination, there exists only a laminar flow at the melted phase, irrespective of the Rayleigh number. Below that inclination, the base state destabilizes following two paths according to the inclination: either leading to a turbulent state for angles near the critical inclination or passing through a regime of plume coarsening before reaching the turbulent state for smaller angles. We find that the Nusselt and Reynolds numbers follow a power law as Nu∼Raα, Re∼Raβ in the turbulent regime. Small inclinations reduce very slightly α and strongly β. The inclination leads to subduction of the kinematic boundary layer into the thermal boundary layer. The scaling laws of the Nusselt and Reynolds numbers and boundary layers are in agreement with different results at high Rayleigh convection. However, some striking differences appear as the stabilization of turbulent states with further increasing of the Rayleigh number. We find as well that the turbulent regime exhibits a higher dispersion in quantities related to heat transfer and flow dynamics on smaller domains.
Ion density of positive and negative ions at ambient pressure in air at 12–136 mm from 4.9 kV soft x-ray source
Authors: Anttalainen Osmo , Lattouf Elie , Kotiaho Tapio , Eiceman Gary
Published: May 2021

The abundance of ions is an essential parameter for ion mobility and mass spectrometry instrument design and for the control or optimization of chemical reactions with reactant ions. This information also advances the study of atmospheric pressure ion kinetics under continuous ionization, which has a role in developing trace level chemical analyzers. In this study, an ionization chamber is described to measure the abundance of ions produced by a 4.9 keV, model L12535, soft x-ray source from Hamamatsu Corporation. Ions of positive and negative polarity were measured independently in an 8 × 30 mm2 cross section at distances of 12–136 mm at ambient air from an uncollimated beam. Ions were collected using electric fields and 16 sets of plates. The ion current decreased exponentially with distance from the source, and the calculated ion concentration varied between 1.0 × 108 and 3.8 × 105 ions cm−3 on plates. A 2D-COMSOL model including losses by recombination and diffusion was favorably matched to changes in ion current intensity in the ionization chamber. Although the ionization chamber was built to characterize a commercial ion source, the design may be considered generally applicable to other x-ray sources.
Numerical investigation of conjugate heat transfer in a microchannel with a hydrophobic surface utilizing nanofluids under a magnetic field
Authors: Mehrizi Abbasali Abouei , Besharati Fatemeh , Jahanian Omid , Hassanzadeh Afrouzi Hamid
Published: May 2021

Conjugate heat transfer in a microchannel with a slip boundary condition imposed on the channel's walls by a uniform magnetic field is studied. The working fluid consists of a Water/Ag mixture nanofluid. A preconditioned lattice Boltzmann method (LBM), formed by combining the incompressible LBM with the regular LBM, is applied to the velocity field and temperature field, respectively. The microchannel's upper wall is thermally isolated when a constant heat flux is imposed on the basin of the microchannel. The simulations are carried out under a variety of different conditions, e.g., various Reynold numbers, Re = 50 and 150, nanoparticle concentrations (φ = 0, 3%), slip coefficients (0 ≤ B ≤ 0.03), and Hartmann numbers (0 ≤ Ha ≤ 30). Surface hydrophobicity results in a reduction of surface friction of up to 46% at B = 0.03 and Ha = 30. The surface friction reductions at Ha = 0, 10, and 20 are 15%, 27%, and 38%, respectively. These results indicate that as the surface slip increases, the drag resisting the fluid dynamics decreases. Moreover, adding the nanoparticles to the base flow can improve the heat transfer by 50%. Besides, using the magnetic field increase the shear stress and, consequently, the drag force dramatically (up 340%). On the other hand, the magnetic field enhances the heat transfer by improving the fluid velocity near the wall, while its effect on the Nu number improvement is not more than 20%. As a result, the magnetic power should be controlled to achieve the best heat transfer performance with the lowest pumping energy consumption.
The circadian clock ensures successful DNA replication in cyanobacteria
Authors: Liao Yi , Rust Michael J.
Published: May 2021

Significance

Cyanobacteria, which are reliant on photosynthesis for growth, face a fundamental challenge. Replicating the genome takes hours, so the decision to initiate replication must be made at time when conditions may be quite different from the future state of the environment when replication is due to complete. We found that cyanobacteria use their circadian clock to ensure that DNA replication finishes efficiently, both by scheduling initiation early in the day and by directing the accumulation of metabolic resources that support ongoing replication after nightfall. When these circadian protections are removed, replication fails to complete. This study connects genome replication to the ability of a circadian clock to anticipate environmental changes.
Presynaptic coupling by electrical synapses coordinates a rhythmic behavior by synchronizing the activities of a neuron pair
Authors: Choi Ukjin , Wang Han , Hu Mingxi , Kim Sungjin , Sieburth Derek
Published: May 2021

Significance

Central pattern generators produce rhythmic behaviors that occur on a variety of timescales. Here, using a simple behavioral circuit that repeats every 50 s in
Caenorhabditis elegans
, we show that electrical synapses composed of the gap junction protein INX-1/innexin are necessary for the precise and accurate timing of the behavioral outputs that are controlled by a biological clock. Electrical synapses do so by both promoting synchronized activation of a pair of coupled neurons in response to the signals from the clock and by inhibiting their inappropriate activation when clock signaling is low. Our findings represent one of the first examples of how the execution of a rhythmic behavior is shaped by electrical synapses through coordinating the activities of coupled neurons.
A solution to a sex ratio puzzle inMelittobiawasps
Authors: Abe Jun , Iritani Ryosuke , Tsuchida Koji , Kamimura Yoshitaka , West Stuart A.
Published: May 2021

Significance

Many social interactions generate "a tragedy of the commons," where individuals would do better if everyone cooperated, but selfish interests can select against cooperation. Examples range from the production of extracellular enzymes by bacteria, to cooperative breeding in animals, to female-biased sex ratios in structured populations, where brothers compete for mates. We examined the offspring sex ratios produced byMelittobiawasps in natural populations and found that females adjust their offspring sex ratio in response to both the presence of other females and whether they had dispersed. Dispersal matters because it determines the genetic relatedness between interacting individuals, and so an analogous influence of dispersal would be predicted for a range of cooperative traits, including parasite virulence.
Equatorial auroral records reveal dynamics of the paleo-West Pacific geomagnetic anomaly
Authors: He Fei , Wei Yong , Maffei Stefano , Livermore Philip W. , Davies Christopher J. , Mound Jon , Xu Kaihua , Cai Shuhui , Zhu Rixiang
Published: May 2021

Significance

The structure of Earth’s ancient magnetic field is constrained by paleomagnetic measurements. However, owing to data sparsity, models need to be smoothed; such smoothing can obscure rapid but crucial fluctuations in the field. We have shown that historical observations of equatorial aurorae can provide added constraints on the dynamics of Earth’s deep interior, suggesting possible fluctuating behavior of a low-intensity geomagnetic anomaly during the seventeenth and eighteenth centuries in the West Pacific. This anomaly is an ancient analogue to the present-day South Atlantic Anomaly, whose existence impacts the functioning of low-Earth orbit satellites. Our study sheds light on the origin, time dependence, and possible future evolution of similar geomagnetic features.
AGO2 promotes tumor progression in KRAS-driven mouse models of non–small cell lung cancer
Authors: Tien Jean Ching-Yi , Chugh Seema , Goodrum Andrew E. , Cheng Yunhui , Mannan Rahul , Zhang Yuping , Wang Lisha , Dommeti Vijaya L. , Wang Xiaoming , Xu Alice , Hon Jennifer , Kenum Carson , Su Fengyun , Wang Rui , Cao Xuhong , Shankar Sunita , Chinnaiyan Arul M.
Published: May 2021

Significance

RAS proteins (HRAS, NRAS, and KRAS) integrate extracellular trophic signals to promote cell proliferation. Constitutively active KRAS drives tumor initiation and progression in nonsmall cell lung cancer (NSCLC). As RAS proteins are often refractory to direct pharmacological inhibition, RAS-interacting proteins are under investigation as potential drug targets. We previously found Argonaute 2 (AGO2) to bind RAS and positively regulate RAS-dependent signaling pathways.
AGO2
knockdown blunted proliferation in NSCLC cells containing a KRAS-activating mutation. Here, we demonstrate that AGO2 promotes tumor progression in multiple mouse models of KRAS-driven NSCLC. In these animals,
Ago2
knockout impairs tumor growth, lowers pathologic grade, and inhibits KRAS signaling. Targeting the AGO2-KRAS interaction may hold future therapeutic promise in NSCLC and other KRAS-driven malignancies.
Physiological concentrations of cyanide stimulate mitochondrial Complex IV and enhance cellular bioenergetics
Authors: Randi Elisa B. , Zuhra Karim , Pecze Laszlo , Panagaki Theodora , Szabo Csaba
Published: May 2021

In mammalian cells, cyanide is viewed as a cytotoxic agent, which exerts its effects through inhibition of mitochondrial Complex IV (Cytochrome C oxidase [CCOx]). However, the current report demonstrates that cyanide’s effect on CCOx is biphasic; low (nanomolar to low-micromolar) concentrations stimulate CCOx activity, while higher (high-micromolar) concentrations produce the “classic” inhibitory effect. Low concentrations of cyanide stimulated mitochondrial electron transport and elevated intracellular adenosine triphosphate (ATP), resulting in the stimulation of cell proliferation. The stimulatory effect of cyanide on CCOx was associated with the removal of the constitutive, inhibitory glutathionylation on its catalytic 30- and 57-kDa subunits. Transfer of diluted
Pseudomonas aeruginosa
(a cyanide-producing bacterium) supernatants to mammalian cells stimulated cellular bioenergetics, while concentrated supernatants were inhibitory. These effects were absent with supernatants from mutant
Pseudomonas
lacking its cyanide-producing enzyme. These results raise the possibility that cyanide at low, endogenous levels serves regulatory purposes in mammals. Indeed, the expression of six putative mammalian cyanide-producing and/or -metabolizing enzymes was confirmed in HepG2 cells; one of them (myeloperoxidase) showed a biphasic regulation after cyanide exposure. Cyanide shares features with “classical” mammalian gasotransmitters NO, CO, and H
2
S and may be considered the fourth mammalian gasotransmitter.
E-H mode transitions and high-energy electron characteristics of helical antenna coupled plasma
Authors: Wang Chuansheng , Lin Xin , Li Fei , Yu Xilong
Published: May 2021

Metastable and high-energy electron characteristics obtained from optical emission spectroscopy are used to analyze the dependence of the H mode on the magnetic field strength and discharge pressure. The results show that the H-mode characteristics gradually appears as the magnetic field strength is increased, the reason being that electrons undergo multiple acceleration-collision cycles at high magnetic field strength, thereby the metastable ionization will be increased. This improves energy utilization and making the H mode appearing. The variation in the density of metastable states and the Langmuir probe data shows that the electron energy distribution function evolves from non-Maxwellian to Maxwellian. The radial constraint of the magnetic field to the electrons and thus reduces the electron heating efficiency. Moreover, the increase in electric field strength with magnetic field leads to an increase in energy obtained by the electrons per unit distance. The competition between the two makes the number of high-energy electrons decrease rapidly first, and then increase slowly with magnetic field strength increasing. The turning point increases with the increase of discharge pressure and radio-frequency (RF) power. And the higher the pressure the lower the high-energy electron. For fields between 105.5 G and 212.7 G. In the H-mode regime, and with increasing RF power, the number of high-energy electrons will be sudden rise after experiencing a steady increase. The sudden rise RF power increase with magnetic field and decrease with discharge pressure increase. However, at high magnetic fields (>265 G) and high power (>450 W), the high-energy electron density decreases with power increasing.
First-principles identification of deep energy levels of sulfur impurities in silicon and their carrier capture cross sections
Authors: Cai Lele , Wang Shanshan , Huang Menglin , Wu Yu-Ning , Chen Shiyou
Published: May 2021

Studies of the deep energy levels and nonradiative carrier capture induced by sulfur doping in silicon were initiated 60 years ago; however, the defect configurations, their deep energy levels, and the carrier capture cross sections are still not well understood. In this study, we focus on SSi substitution, and perform a first-principles study of its defect configurations and the deep energy levels using hybrid exchange-correlation functional. We discover a new distortive configuration for SSi
+ besides the previously obtained structure with higher symmetry. For both SSi
+ configurations, the deep transition levels

ε

(0/+) and

ε

(+/2+) are determined as 0.35 eV and 0.68 eV below the conduction band minimum, respectively. As a benchmark calculation, the hole-capture cross sections for neutral and +1 charged states are obtained based on the distortive structure. The cross section for SSi
+ agrees with the experiment, demonstrating the multi-phonon process for SSi
+ capturing a hole, whereas the cross section of SSi
0 is significantly lower than the experimental data because hole capture by SSi
0 is an Auger-type process. Our calculations provide a benchmark for the evaluation of the cross section of carrier capture in semiconductors using multi-phonon nonradiative recombination theory.
Semiconductor nanowire arrays for optical sensing: a numerical insight on the impact of array periodicity and density
Authors: Zagaglia Luca , Demontis Valeria , Rossella Francesco , Floris Francesco
Published: May 2021

Recent advances in the nanofabrication and modeling of metasurfaces have shown the potential of these systems in providing unprecedented control over light–matter interactions at the nanoscale, enabling immediate and tangible improvement of features and specifications of photonic devices that are becoming always more crucial in enhancing everyday life quality. In this work, we theoretically demonstrate that metasurfaces made of periodic and non-periodic deterministic assemblies of vertically aligned semiconductor nanowires can be engineered to display a tailored effective optical response and provide a suitable route to realize advanced systems with controlled photonic properties particularly interesting for sensing applications. The metasurfaces investigated in this paper correspond to nanowire arrays that can be experimentally realized exploiting nanolithography and bottom-up nanowire growth methods: the combination of these techniques allow to finely control the position and the physical properties of each individual nanowire in complex arrays. By resorting to numerical simulations, we address the near- and far-field behavior of a nanowire ensemble and we show that the controlled design and arrangement of the nanowires on the substrate may introduce unprecedented oscillations of light reflectance, yielding a metasurface which displays an electromagnetic behavior with great potential for sensing. Finite-difference time-domain numerical simulations are carried out to tailor the nanostructure parameters and systematically engineer the optical response in the VIS-NIR spectral range. By exploiting our computational-methods we set-up a complete procedure to design and test metasurfaces able to behave as functional sensors. These results are especially encouraging in the perspective of developing arrays of epitaxially grown semiconductor nanowires, where the suggested design can be easily implemented during the nanostructure growth, opening the way to fully engineered nanowire-based optical metamaterials.
Balanced charge transport and enhanced performance of blue quantum dot light-emitting diodes via electron transport layer doping
Authors: Yang Yue , Su Liang , Feng Nannan , Liu Anqi , Xing Xiaoxue , Lu Min , Yu William W
Published: May 2021

The unbalanced charge transport is always a key influencing factor on the device performance of quantum dot light-emitting diodes (QLEDs), particularly for the blue QLEDs due to their large optical band gap. Here, a method of electron transport layer (ETL) doping was developed to regulate the energy levels and the carrier mobility of the ETL, which resulted in more balanced charge injection, transport and recombination in the blue emitting CdZnS/ZnS core/shell QLEDs. Consequently, an enhanced performance of blue QLEDs was achieved by modulating the charge balance through ETL doping. The maximum external quantum efficiency and luminance was dramatically increased from 2.2% to 7.3% and from 3786 cd m−2 to 9108 cd m−2, respectively. The results illustrate that charge transport layer doping is a simple and effective strategy to regulate the charge injection barrier and carrier mobility of QLEDs.
Efficient inverse design and spectrum prediction for nanophotonic devices based on deep recurrent neural networks
Authors: Yan Ruoqin , Wang Tao , Jiang Xiaoyun , Huang Xing , Wang Lu , Yue Xinzhao , Wang Huimin , Wang Yuandong
Published: May 2021

The development of nanophotonic devices has presented a revolutionary means to manipulate light at nanoscale. How to efficiently design these devices is an active area of research. Recently, artificial neural networks (ANNs) have displayed powerful ability in the inverse design of nanophotonic devices. However, there is limited research on the inverse design for modeling and learning the sequence characteristics of a spectrum. In this work, we propose a deep learning method based on an improved recurrent neural network to extract the sequence characteristics of a spectrum and achieve inverse design and spectrum prediction. A key feature of the network is that the memory or feedback loops it comprises allow it to effectively recognize time series data. In the context of nanorods hyperbolic metamaterials, we demonstrated the high consistency between the target spectrum and the predicted spectrum, and the network learned the deep physical relationship concerning the structural parameter changes reflected on the spectrum. The effectiveness of our approach is also tested by user-drawn spectra. Moreover, the proposed model is capable of predicting an unknown spectrum based on a known spectrum with only 0.32% mean relative error. The prediction model may be helpful to predict data beyond the detection limit. We propose this versatile method as an effective and accurate alternative to the application of ANNs in nanophotonics, paving way for fast and accurate design of desired devices.
Alpha particle detector with planar double Schottky contacts directly fabricated on semi-insulating GaN:Fe template*
Authors: Yang Qun-Si , Liu Qing , Zhou Dong , Xu Wei-Zong , Wang Yi-Wang , Ren Fang-Fang , Lu Hai
Published: May 2021

Alpha particle radiation detectors with planar double Schottky contacts (DSC) are directly fabricated on 5-μm-thick epitaxial semi-insulating (SI) GaN:Fe film with resistivity higher than 1 × 108 Ω ⋅cm. Under 10 V bias, the detector exhibits a low dark current of less than 5.0 × 10−11 A at room-temperature, which increases at higher temperatures. Linear behavior in the semi-log reverse current–voltage plot suggests that Poole–Frenkel emission is the dominant carrier leakage mechanism at high bias. Distinct double-peak characteristics are observed in the energy spectrum of alpha particles regardless of bias voltage. The energy resolution of the SI-GaN based detector is determined to be ∼ 8.6% at the deposited energy of 1.209 MeV with a charge collection efficiency of ∼ 81.7%. At a higher temperature of 90 °C, the measured full width at half maximum (FWHM) rises to 235 keV with no shift of energy peak position, which proves that the GaN detector has potential to work stably in high temperature environment. This study provides a possible route to fabricate the low cost GaN-based alpha particle detector with reasonable performance.
Research on Guidance and Control Law Design of Decelerating Transition and Vertical Landing for a STOVL UAV
Authors: Dong Zixu , Ren Yang , Chen Kun , Chen Yaohui
Published: May 2021

In this paper, an integrated design method for guidance and control laws for a short takeoff and vertical landing (STOVL) unmanned aerial vehicle (UAV) during decelerating transition and vertical landing phases under thrust vector control is studied. Based on the principle of time-scale separation, the outer-loop guidance law adopts an implicit dynamic inverse method to provide attainable overload vector control instructions for decelerating transition and vertical landing phases. Meanwhile, the inner-loop control law adopts an improved eigen-structure assignment method, which tracks guidance instructions and maintains a stable attitude. The attitude nozzles are joined to the attitude control with the dropping of dynamic pressure, thereby assisting aerodynamic surfaces to stabilize attitudes. Subsequently, the feasibility and effect of the control methods for a STOVL UAV during decelerating transition and vertical landing phases are verified by a 6-DOF flight simulation platform. The simulation results demonstrate that the integrated design method is beneficial for a quick evaluation of the overall scheme.
Performance of backpropagation artificial neural network to predict el nino southern oscillation using several indexes as onset indicators
Authors: Aprilia B , Marzuki  , Taufiq I
Published: May 2021

El Nino Southern Oscillation (ENSO) is a world’s climate anomaly that occurs repeatedly, unavoidable, has significant natural disaster impact for countries around the Pacific Ocean include Indonesia. ENSO has a time series of predictors, so it can be predicted the Artificial Neural Network (ANN). ANN has several important advantages over the more statistical models traditionally used. ANNs can accommodate non-linear relationship and the flexibility in testing multiple inputs. This research aims to predict the onset of ENSO using the ANN-backpropagation method of learning rate and momentum variation. The prediction is based on several indexes during 1979-2018, i.e., Sea Surface Temperature (Nino 1.2, Nino 3, Nino 3.4, and Nino 4), Southern Oscillation Index (SOI), Multivariate ENSO and then verified with prediction data from the International Research Institute (IRI). The results of this prediction stated that in the period JAS (July-August-September) and DJF (December-January-February) 2020/2021 world climate conditions are in normal ENSO in which there are no El Nino and La Nina phenomena. Thus, the ANN-backpropagation method is an appropriate method to predict ENSO.
Effect of ansatz on soliton propagation pattern in photorefractive crystals
Authors: Ripai A , Sutantyo Trengginas E P , Abdullah Z , Syafwan M , Hidayat W
Published: May 2021

Soliton propagation and some related parameter in a photorefractive crystal are considered. This study analyzes the soliton propagation on a photorefractive crystal having both linear and quadratic electro-optical effects through a time-dependent model of nonlinear dynamics equation using the numerical split-step Fourier method. In conducting analysis, we apply various models of ansatz as initial conditions of the optical beam envelope. Based on the studies conducted, ansatz influences the soliton propagation pattern in the photorefractive crystals. Besides, we found ansatz in secant-hyperbolic and Gaussian functions as the most appropriate model for realizing solitons in crystals. Finally, the photorefractive effect supports the evolution of soliton before it achieved a level of stability.
Relationship between cloud vertical structures inferred from radiosonde humidity profiles and precipitation over Indonesia
Authors: Lismalini  , Marzuki  , Ali Shafii M , Yusnaini H
Published: May 2021

Knowledge of cloud vertical structure, including the presence of multiple cloud layers, is important for several climate-related applications such as for understanding the impact of clouds on Earth’s radiation budget. Moreover, the vertical distribution of latent heat release that affects global circulation and precipitation. The characteristics of cloud vertical structure may change as a consequence of climate change. However, study on cloud vertical structure in Indonesia is limited to case study based on short period observation. This study aims to analyse the vertical structure of clouds, such as cloud base height (CBH), the height of the cloud top (CT) and the number of cloud layers due to climate change in Indonesia, based on ∼ 30 years radiosonde observation. The relation between cloud vertical structures and precipitation was investigated. We used the radiosonde data from nine observation stations in Indonesia. On an average, it is observed that over Indonesia one-layer clouds is most frequently observed cloud, more than 60% of the time. This number is much larger than the fraction of single layer clouds over the globe which is about 58 % of the time. The cloud vertical structures in Indonesia vary from month to month. The cloud vertical structure during wet and dry season is different which indicate a strong relationship between cloud vertical structure and precipitation.
Detection of buried human bodies using ground-penetrating radar method
Authors: Bagaskara Adika , Wafi Abdurrahman , Setiawan Nugroho Syarif , Mariyanto Mariyanto
Published: May 2021

Indonesia is a country that often experiences natural disasters as it is a meeting point of several tectonic plates. When a natural disaster occurs, most of the time the evacuation team having some trouble finding the buried victims underground. The Ground-Penetrating Radar (GPR) method is one of the solutions for this problem. GPR or also called georadar is a geophysical method that is used to investigate conditions under the earth’s surface using electromagnetic waves. This study aims to detect buried human bodies underground using the GPR method to increase the effectiveness and efficiency of natural disaster victims by doing a simulation measurement. It took place in one of the public cemeteries in Jakarta, Indonesia passing two graves with corpses buried around three years before the survey. GPR measurements were conducted using Geoscanners AKULA A9000+ Antenna GCB3070 to detect the buried human bodies underground. The GPR data then processed using MATLAB based program called matGPR. A series of adjustments and filters such as signal position adjustment, remove DC, mean filter, inverse amplitude decay, remove global background, and Karhunen-Loeve (KL) filter have been applied to the data. The result of data processing shows amplitude contrasts which are suspected to be the buried corpses. Further research can be conducted to investigate the buried victims from landslides, earthquakes, and other natural disasters.
Application of complementary split ring resonator to focus microwave for cancer treatment using the hyperthermia method
Authors: Yusri R , Muldarisnur
Published: May 2021

The hyperthermia method for cancer treatment aims to select and eliminate cancer and normal cells by raising the temperature of the cancer cells in the 36-48 using radiation from electromagnetic waves, while normal cells are kept at ambient temperature. This research is conducted by simulating an applicator as a complementary Split Ring Resonator (cSRR) in the radio frequency range of 434-915 MHz using Finite Element Method. The average temperature distribution of cancer cells in the shape of a ball 1 mm in diameter with a position of 5 mm from the port reaches 55.5 . Cell size variations show a different temperature distribution, larger cell sizes (5 mm in diameter) have decreased in temperature distribution which only reached around 46.1 . This temperature distribution is also caused by the position of the cell against the port, the cell is shifted away from the port which results in a temperature distribution of 43.3 . So that the optimal size and position of cancer cell for this treatment is as small as and as close as the cell with port. This data shows that the cSRR applicator can be used for the hyperthermia method.
Deterministic seismic hazard analysis for assessing earthquake hazard in Sungai Penuh and Kerinci Regency
Authors: Resta Ichy Lucya , Apriliyani Devi Putri , Nasri MZ , Juventa  , Dewi Ira Kusuma
Published: May 2021

Assessment of seismic hazard is necessary in land use planning and hazard mitigation. It leading to subdivided a region into sub-region which different safeguards to prevent damage in case an earthquake is occurred. The quantitative assessment of seismic hazard is carried out in Sungai Penuh and Kerinci Regency using deterministic seismic hazard analysis (DSHA) method. Earthquake scenario of Mw7 at depth of 10 km by Siulak fault source were used for analysis to estimate the ground motion over the investigated areas. The resulting DSHA map reveals high seismic hazard level in terms of PGA 49.8 – 71.9 gal alongside the active Siulak fault zones. The intensity of the region are dominated by VII-VII of MMI scale which puts in the high hazard zone.
Reservoir fluid production optimization to sustain net-present value (NPV) using gradient-based Quasi-Newton method
Authors: Salim C , Wahjudhi S M , Mariyanto
Published: May 2021

After several years of production, the strong water drive reservoir can have high water cut. Unlike hydrocarbon, water has no commercial value, and tends to be disposed or separated. This leads to the decline in net present value (NPV) of reservoir. To sustain reservoir’s NPV for as long as possible, a gradient-based Quasi-Newton optimization in reservoir simulation is proposed. This mathematical method uses BFGS algorithm to find the minimum of the objective function of reservoir production. This method also assumes constant production and injection rate. Initially, the algorithm produces the base NPV (before optimized using Quasi-Newton method). After that, BFGS generates optimized NPV by iterating line search in the objective function until it meets the stopping criterion. This algorithm also shows the optimized oil and water production curve. These comparisons show how oil and water should be produced to sustain the NPV. The results show that the water cut value is decreased and NPV decline happens later than the non-optimized NPV. As a conclusion, to answer the sustainable energy needs, Quasi-Newton method using BFGS algorithm and its improvements are suitable to sustain the reservoir production in the long run.
Influence of topography on lightning density in Sumatra
Authors: Yusnaini H , Marzuki  , Muharsyah R , Vonnisa M , Tangang F
Published: May 2021

Lightning is one phenomenon that plays an essential role in weather modeling and forecasts. Moreover, lightning also has an impact on humans and facilities. Lightning shows variations both temporally and spatially. In this study, the spatial distribution of lightning in Sumatra was examined to see topography’s effect on lightning density in this region. We analyzed lightning data from the World Wide Lightning Location Network (WWLLN) observation. Topographic data, particularly the altitude and terrain slope data, were obtained from the digital elevation model (DEM) Shuttle Radar Topography Mission (SRTM). It was found that the lightning density is slightly correlated with the terrain slope and the altitude. High concentrations of lightning are observed in the land, consistent with some previous studies. Lower concentrations are seen on Sumatra’s western side, particularly in the hillside of the Barisan Mountains. Although Sumatra’s eastern side has a low elevation and a small topography slope, a high lightning concentration is observed in this region. The distribution of lightning shows seasonal variation in which the largest density is found during the dry season (MAM), which is different from the previous studies.
Effect of gamma ray normalization on net pay calculation, a case study of “PE” field, central Sumatra basin
Authors: Cahyaningati W P , Mariyanto M , Lestari W , Amelia R , Yusroni S A , Sapdawati S
Published: May 2021

Reservoir’s quality is very important in exploration of oil and gas. This quality can be used to determine the productive field including the reserve itself. To analyse the reservoir quality, net pay thickness needs to be determined. However, different quality of logging tools will affect the log reading and thickness interval. Therefore, it needs to be normalized in order to equalize the reading of minimum and maximum log values in interest zone. This study is intended to interpret the impact of gamma ray normalization on net calculation. The net pay calculation is carried out with and without normalization. To do normalization, cumulative percentile used are 3% and 93%. For instance, before normalization, the highest net pay in PE_35 is 12ft. After P93 and P3 normalization, the highest net pay value become 13.5ft and 51.5ft respectively. If the net pay value of PE_35 using P3 normalization is compared to the net pay value before normalized, then the normalized value is optimized more than 5%, which is a good amount of optimization. Thus, to obtain an optimistic net pay value, normalization must be done. To conclude this study, 3% cumulative percentile normalization method has shown the most optimistic net pay value increase.
Design on-board data processing for double Langmuir probe on lean satellite
Authors: Suryana R , Tejumola T W , Kim S , Cho M
Published: May 2021

The explosive growth of lean satellites (small/micro/nano/pico) has positioned this class of satellites as a unique tool for space science missions. Langmuir probe is one of the most frequently used payloads to achieve space plasma measurement missions because of their low requirement in terms of system development, size, and relatively low power requirements to drive the mission. Double Langmuir probe can overcome the limitations of a single Langmuir probe measurement as reference ground in the satellite is not required. The limitation of data communication speed is one of the problems that always occur in the development of a multi-mission lean satellite. Data communication speed can be improved by using another system such as S-band or X-band, but those will be required for high power consumption. One of the solutions is the reduced size of the data by using on-board data processing on satellites. On-board data processing aims to improve data communication speed when sending DLP data to ground stations and how to determine plasma parameters. On-board data processing for a double Langmuir probe will be calculated electron temperature and electron density by using Raspberry PI zero. On-board data processing aims to reduce the size of data so that the time of transmission between satellite and ground stations will be shorter. On-board data processing can be a pragmatic solution because processed data only contains useful information according to user requirements.
Bacterial cellulose-rambutan leaf extract (Nephelium lappaceum L.) composite: preparation and characterization
Authors: Putra Ananda , Sari Reci Purnama , Nasra Edi , Yuniarti Elsa , Amran Ali
Published: May 2021

The purpose of this research is to produce bacterial cellulose-rambutan leaf extract (BC-RLE) composite. The BC-RLE composite was prepared by immersing BC gel into RLE under various immersion time of 7, 14 and 21 days with/without using UV light radiation, and then, its physical (water content, and swelling), mechanical (tensile and compressive strength) and structural (functional group and degree of crystallinity) properties were characterized. The results showed that the water content of BC-RLE composites was lower than that of pure BC gel and decreased as increased immersion time of BC gel in RLE. Further, the UV light radiation is given during immersion of BC gel in RLE also reduced the water content of BC-RLE composites. However, the swelling degree of BC-RLE composites increased as increased immersion time, and a similar tendency was also shown by applying the UV light radiation. Mechanical properties, tensile, and compressive strength of BC-RLE composites increased as increased immersion time and by applying UV light radiation. The FTIR results showed that there was no effect of UV light radiation on the structure of BC-RLE composites. The Degree of crystallinity of BC-RLE composite decreased by applying the UV light radiation during immersion time.