bluuebunny/crossref_metadata_2025 huggingface dataset:
α
-In2Se3 based ferroelectric-semiconductor metal junction for non-volatile memories
Authors: Saha Atanu K. , Si Mengwei , Ye Peide D. , Gupta Sumeet K.
Published: November 2020

In this work, we theoretically and experimentally investigate the working principle and nonvolatile memory (NVM) functionality of a 2D α-In2Se3-based ferroelectric-semiconductor-metal-junction (FeSMJ). First, we analyze the semiconducting and ferroelectric properties of the α-In2Se3 van der Waals (vdW) stack via experimental characterization and first-principles simulations. Then, we develop a FeSMJ device simulation framework by self-consistently solving the Landau–Ginzburg–Devonshire equation, Poisson's equation, and charge-transport equations. Based on the extracted Fe-semiconductor (FeS) parameters, our simulation results show good agreement with the experimental characteristics of our fabricated α-In2Se3-based FeSMJ. Our analysis suggests that the FeS polarization-dependent modulation of Schottky barrier heights of FeSMJ plays a key role in providing the NVM functionality. Besides, the appearance of mobile carriers in FeS due to its semiconducting properties leads to a non-uniform electric field. This further induces partial polarization switching in the FeS layers, resulting in asymmetry in the FeSMJ characteristics for positive and negative voltages. Moreover, we show that the thickness scaling of FeS leads to a reduction in read/write voltage and an increase in distinguishability. Array-level analysis of FeSMJ NVM suggests a lower read-time and read-write energy with respect to the HfO2-based ferroelectric insulator tunnel junction.
A perspective on MXenes: Their synthesis, properties, and recent applications
Authors: Papadopoulou Konstantina A. , Chroneos Alexander , Parfitt David , Christopoulos Stavros-Richard G.
Published: November 2020

Since 2011, after the discovery of new ceramic two-dimensional materials called MXenes, the attention has been focused on their unique properties and various applications, from energy storage to nanomedicine. We present a brief perspective article of the properties of MXenes, alongside the most recent studies regarding their applications on energy, environment, wireless communications, and biotechnology. Future needs regarding the current knowledge about MXenes are also discussed in order to fully understand their nature and overcome the challenges that have restricted their use.
Berry phases in the reconstructed KdV equation
Authors: Oblak Blagoje , Kozyreff Gregory
Published: November 2020

We consider the KdV equation on a circle and its Lie–Poisson reconstruction, which is reminiscent of an equation of motion for fluid particles. For periodic waves, the stroboscopic reconstructed motion is governed by an iterated map whose Poincaré rotation number yields the drift velocity. We show that this number has a geometric origin: it is the sum of a dynamical phase, a Berry phase, and an “anomalous phase.” The last two quantities are universal: they are solely due to the underlying Virasoro group structure. The Berry phase, in particular, was previously described by Oblak [J. High Energy Phys. 10, 114 (2017)] for two-dimensional conformal field theories and follows from adiabatic deformations produced by the propagating wave. We illustrate these general results with cnoidal waves, for which all phases can be evaluated in closed form thanks to a uniformizing map that we derive. Along the way, we encounter “orbital bifurcations” occurring when a wave becomes non-uniformizable: there exists a resonance wedge, in the cnoidal parameter space, where particle motion is locked to the wave, while no such locking occurs outside of the wedge.
The influence of boundary and edge-plasma modeling in computations of axisymmetric vertical displacement
Authors: Bunkers K. J. , Sovinec C. R.
Published: November 2020

A number of previously published studies apply extended-magnetohydrodynamics (MHD) computations to model macroscopic dynamics of tokamak vertical displacement events (VDEs). The characteristic plasma-wall contact and resistive-wall diffusion imply sensitivity to boundary conditions in a general sense, but which conditions have significant influence depends on how the plasma is modeled. This work examines these dependencies by comparing results of axisymmetric extended-MHD computations with different sets of boundary conditions, plasma thermal-conduction models, and wall resistivity values. The geometry and plasma parameters of the computations represent a modest-sized tokamak. The forced-displacement scenario and computational setup are similar to those used in previous 3D computations [C. R. Sovinec and K. J. Bunkers, Phys. Plasma Controlled Fusion 61, 024003 (2019)]. The results show that for a given wall resistivity, the VDE time scale is most sensitive to variations in the boundary and thermal-conduction parameters that affect electron thermal transport. The electrical conductivity depends on electron temperature, and the dependence on thermal transport stems from its influence on the electrical circuit that includes the open-field halo current. Conditions that lead to hotter, broader halo regions slow the evolution. Significant sensitivity to the boundary condition on plasma flow-velocity exists when electron thermal conduction is restricted and electron energy loss is convective, which is expected for conditions at the entrance of the magnetic presheath.
Multi-faceted spectroscopic mapping of ultrafast nonadiabatic dynamics near conical intersections: A computational study
Authors: Sun Kewei , Xie Weiwei , Chen Lipeng , Domcke Wolfgang , Gelin Maxim F.
Published: November 2020

We studied spectroscopic signatures of the nonadiabatic dynamics at conical intersections formed by the lowest excited singlet states in pyrazine. We considered two ab initio models of conical intersections in the excited states of pyrazine developed by Sala et al. [Phys. Chem. Chem. Phys. 16, 15957 (2014)]: a two-state (B2u and B3u), five-mode model and a three-state (B2u, B3u, and Au), nine-mode model. We simulated the signals of three widely used techniques: time- and frequency-resolved fluorescence spectroscopy, transient absorption pump–probe spectroscopy, and electronic two-dimensional spectroscopy. The signals were calculated through third-order response functions, which, in turn, were evaluated with the numerically accurate multiple Davydov ansatz. We establish spectroscopic signatures of the optically dark Au state and demonstrate that the key features of the photoinduced dynamics, such as electronic/nuclear populations, electronic/nuclear coherences, and electronic/nuclear energy transfer processes, are imprinted in the spectroscopic signals. We show that a fairly complete picture of the nonadiabatic dynamics at conical intersections can be obtained when several spectroscopic techniques are combined. Provided that the time resolution is sufficient, time- and frequency-resolved fluorescence may provide the best visualization of the nonadiabatic dynamics near conical intersections.
A functional CMOS compatible MEMS pyroelectric detector using 12%-doped scandium aluminum nitride
Authors: Ng D. K. T. , Zhang T. , Siow L. Y. , Xu L. , Ho C. P. , Cai H. , Lee L. Y. T. , Zhang Q. , Singh N.
Published: November 2020

In this paper, we fabricate and demonstrate a functional complementary metal-oxide-semiconductor (CMOS) compatible pyroelectric uncooled thermal detector using 12% doped Scandium Aluminum Nitride (ScAlN) as the sensing layer. The ScAlN pyroelectric material is deposited at a temperature of ∼200 °C over an 8-in. wafer area. This detector has shown, in general, improved performance compared to AlN, with specific detectivity as high as ∼ 6.08×107 cm Hz/W and noise equivalent power as low as ∼ 8.85×10−10  W/Hz. The results show the specific detectivity of ScAlN-based pyroelectric detectors in the range of 107 cm Hz/W, which is an improvement compared to AlN-based pyroelectric detectors which report specific detectivity typically in the range of 105–106  cm Hz/W. This promising result opens up the opportunities for a CMOS compatible, 8-in. wafer-level manufacturable lead-free pyroelectric detector toward low cost and high throughput, allowing microelectromechanical systems (MEMS) and CMOS integration for increased applications in CMOS–MEMS integrated devices utilizing pyroelectric detectors.
Degradation of REBCO coated conductors due to a combination of epoxy impregnation, thermal cycles, and quench: Characteristics and a method of alleviation
Authors: Yin Shijian , Duranti Mattia , Swenson Charles A. , Li Pei , Ye Liyang , Zhang Xingguo , Shen Tengming
Published: November 2020

REBa2Cu3Ox (REBCO) coated conductors are an enabling technology for >1 GHz nuclear magnetic resonance spectrometers that need >23.5 T solenoids, compact high-field fusion reactors beyond the International Thermonuclear Experimental Reactor, and 20 T class accelerator magnets. An in-depth understanding of stress and strain management is critically needed for these applications. Here, we report experimental data and an analysis of damages of REBCO-coated conductors in several scenarios relevant for their applications in high-field magnets and unique to their multi-layer thin film structure. The examined scenarios include failure induced by quench, failure induced by epoxy impregnation, and failure induced by a combination of epoxy impregnation and quench. The root cause is film blistering and peeling induced by thermally interfacial stresses characteristic of multilayered heteroepitaxial thin film structures on thick substrates utilized. The quantitative stress analysis is introduced using simple and easy to use formulas and clearly indicates how materials and structural characteristics affect the magnitude and the distribution of stresses and deflections. Finally, a simple method is introduced for removing degradation of REBCO coated conductors due to epoxy impregnation. Our data and analysis help our understanding of the practical limit of REBCO-coated conductors and can be utilized as a guidance for the physical design of REBCO coated conductors and high-current cables assembled from them and for minimizing damages.
Ansatz for the Jahn–Teller triplet instability
Authors: Ceulemans Arnout , Szabó P. Bernát
Published: November 2020

A threefold degenerate electronic state is Jahn–Teller unstable with respect to symmetry lowering distortions, which transform as the five quadrupolar modes. The solution of the corresponding vibronic Hamiltonian is constructed using the analytical method introduced by Bargmann, as an alternative to existing group-theoretical techniques based on coefficients of fractional parentage. It involves the construction of an ansatz that incorporates SO(5) to SO(3) symmetry breaking. The resulting Jahn–Teller equations are derived and solved in terms of radial polynomials and Gegenbauer functions.
Real-time detection of cardiac troponin I and mechanism analysis of AlGaAs/GaAs high electron mobility transistor biosensor
Authors: Luo Jiaming , Li Sufang , Xu Mengke , Guan Min , Yang Mengxi , Ren Jingyi , Zhang Yang , Zeng Yiping
Published: November 2020

The high electron mobility transistor (HEMT)-based biosensors are highly competitive in the ultimate application of portable and point-of-care testing. Herein, we have demonstrated highly sensitive and real-time detection of cardiac troponin I (cTnI), a biomarker for the diagnosis of acute myocardial infarction (AMI) using AlGaAs/GaAs HEMT-based biosensors. The device has achieved a lower detection limit of 1 pg/ml in the buffer solution and less than 30 s response time, which demonstrated significant promise in the early diagnosis and screening of AMI. In addition, our results are consistent with the enzyme-linked immunosorbent assay according to the AMI patient’s blood test results. Furthermore, by comparing the two HEMT structures, we also calculated the equilibrium dissociation constant (KD) of the cTnI and cTnI antibody and analyzed the sensing mechanism. The results show that this method is very promising for early diagnosis of AMI.
Effect of excessive Cs and O on activation of GaAs(100) surface: From experiment to theory
Authors: Zhang Yijun , Zhang Kaimin , Li Shiman , Li Shan , Qian Yunsheng , Shi Feng , Jiao Gangcheng , Miao Zhuang , Guo Yiliang , Zeng Yugang
Published: November 2020

The surface Cs–O activation process directly determines quantum efficiency and stability of negative-electron-affinity photocathodes. To investigate the effects of excessive Cs and O supply on activation and to explore a more effective Cs–O activation recipe, Cs–O activation experiments of GaAs(100) photocathodes are carried out based on the current-driven solid Cs and O dispensers. By a comparison of differences in activation photocurrent, quantum efficiency, and photocurrent decay, it is found that the recipe of excessive O and non-excessive Cs is not suitable for activating GaAs photocathodes, while the recipe of continuous and completely excessive Cs along with intermittent and non-excessive O can achieve the most excellent photoemission performance, including the highest quantum efficiency in the long-wave threshold region and best stability under intense light irradiation after activation. Furthermore, this improved activation recipe with the least Cs–O alternating cycles is easier to operate. Combined with density functional calculations and dipole layer model, it is found that the activation recipe of completely excessive Cs and non-excessive O can form effective dipoles to the greatest extent, and avoid the direct interaction between As atoms and O atoms to form As–O–Ga oxides on the GaAs(100) reconstructed surface.
A Perspective on acoustical tweezers—devices, forces, and biomedical applications
Authors: Drinkwater Bruce W.
Published: November 2020

Acoustical tweezers are devices that use acoustic radiation forces to trap and maneuver objects. This Perspective focuses on the biomedical applications of these devices, and hence, the target objects include cells, cell clusters, and micro-organisms. These objects are of microscopic size and have acoustic properties similar to the water-like biological media in which they are found. The character of the acoustic radiation forces is first discussed as is a selection of the expanding range of biomedical applications. Future directions are then described, which include increased integration of acoustical tweezers with other biomedical technology, approaches that allow increased functionality at the single-cell level, and a move toward quantitative measurements such as cell stiffness.
Riccati transfer matrix method for linear multibody systems with closed loops
Authors: Gu J. J. , Rui X. T. , Zhang J. S.
Published: November 2020

The Riccati transfer matrix method (RTMM) improves the numerical stability of analyzing chain and tree multibody systems with the transfer matrix method for multibody systems. However, for linear multibody systems with closed loops, the recursive relations of the Riccati transfer matrices are yet to be established. Therefore, it is difficult to compute linear multibody systems with closed loops using the RTMM. In this paper, a new Riccati transformation for such systems is established by transforming the system into a derived tree system by cutting the closed loops. An RTMM formalism for general linear multibody systems with closed loops is then formulated based on the chain and tree multibody systems. The steady-state response under harmonic excitation is taken as an example to validate the proposed method.
Elastic softening of bulk modulus of monoclinic HfO2 under high pressure
Authors: Akahama Yuichi , Kawaguchi Saori , Hirao Naohisa , Ohishi Yasuo
Published: November 2020

In this study, the lattice compression properties of monoclinic HfO2 (m-HfO2) at room temperature are investigated by performing high-pressure powder x-ray diffraction experiments. The lattice constants are precisely determined from the Rietveld analysis. The linear compressibility of each crystal axis a, b, and c is estimated as 10.0 × 10−3, 3.8 × 10−3, and 12.7 × 10−3/GPa, respectively, indicating a strong anisotropy. The equation of state for m-HfO2 is obtained using the third-order Birch–Murnaghan equation based on the volume and pressure data. The obtained unit cell volume (V0), bulk modulus (B0), and its pressure derivative (B0′) at ambient pressure are 138.3(1) Å, 195(2) GPa, and –5.4(5), respectively. The negative value of B0′ implies the bulk modulus softening with an increase in pressure. The fact that the elastic softening has also been observed in m-ZrO2 suggests that the abnormal behavior is a characteristic of the monoclinic structure (P21/c). The transition to the orthorhombic phase is observed at approximately 6.4 GPa. The transition is sluggish, and two phases coexist at a pressure of up to 10 GPa.
Research on the emitter thickness optimization of GaInP/GaAs/Ge triple-junction solar cell under space proton irradiation based on TCAD simulation
Authors: Li Junwei , Wang Jintao , Shi Chengying , Wang Zujun , Xue YuanYuan
Published: November 2020

The degradation of GaInP/GaAs/Ge triple-junction solar cells with different GaAs sub-cell emitter thickness induced by proton irradiation is studied using numerical simulation. The degradation results of triple-junction solar cells with different GaAs emitter thickness have been investigated. The degradation mechanism induced by proton irradiation is analyzed. The results show that the short-circuit current and maximum power increase first and then decrease with the increase in GaAs sub-cell emitter thickness. The degradation of the GaAs sub-cell external quantum efficiency is greater than that of the GaInP sub-cell induced by proton irradiation. Meanwhile, the remaining external quantum efficiency of the GaAs sub-cell first increases and then decreases with the increase in emitter thickness after proton irradiation.
Spin–orbit torques in structures with asymmetric dusting layers
Authors: Razavi Armin , Wu Hao , Dai Bingqian , He Haoran , Wu Di , Wong Kin , Yu Guoqiang , Wang Kang L.
Published: November 2020

Current-induced spin–orbit torques (SOTs) in heavy metal/ferromagnet heterostructures have emerged as an efficient method for magnetization switching with applications in nonvolatile magnetic memory and logic devices. However, experimental realization of SOT switching of perpendicular magnetization requires an additional inversion symmetry breaking, calling for modifications of the conventional SOT heterostructures. In this work, we study SOTs and deterministic switching of perpendicular magnetization by inserting different asymmetric dusting layers at the heavy metal/ferromagnet interface. Similar to the previous works with lateral structural asymmetry, we study the emergence of current-induced perpendicular effective magnetic fields (Hzeff). By examining three different material combinations of heavy metal/dusting layers (W/IrMn, Pt/IrMn, and W/Ta), we shed light on the origins of Hzeff; we show that Hzeff is generically created in all the studied asymmetric structures, has a close correlation with the interfacial magnetic anisotropy, and is independent of the signs of spin Hall angles of the materials. Furthermore, we show that the induction of Hzeff enables field-free deterministic SOT switching of perpendicular magnetization. Our results can be used in designing SOT heterostructures for practical applications in nonvolatile technologies.
Dynamics of a qubit-oscillator system with periodically varying coupling
Authors: Amico Mirko , Kezerashvili Roman Ya
Published: November 2020

The dynamics of qubits coupled to a harmonic oscillator with time-periodic coupling is investigated in the framework of Floquet theory. This system can be used to model nonadiabatic phenomena that require a periodic modulation of the qubit/oscillator coupling. The case of a single qubit coupled to a resonator populated with n = 0, 1 photon is explicitly treated. The time-dependent Schrödinger equation describing the system’s dynamics is solved within the Floquet formalism and compared to a solution obtained with perturbative approaches in the time- and Laplace-domain. Excellent quantitative agreement is found between the analytical and numerical calculations within the Floquet approach, demonstrating the effectiveness of the technique for the study of the dynamical Lamb effect.
Metal–insulator transition in epitaxial Ga-doped ZnO films via controlled thickness
Authors: Mukherjee Joynarayan , Nanda B R K , Ramachandra Rao M S
Published: November 2020

Understanding and tuning of metal–insulator transition (MIT) in oxide systems is an interesting and active research topics of condensed matter physics. We report thickness dependent MIT in Ga-doped ZnO (Ga:ZnO) thin films grown by pulsed laser deposition technique. From the electrical transport measurements, we find that while the thinnest film (6 nm) exhibits a resistivity of 0.05 Ω cm, lying in the insulating regime, the thickest (51 nm) has resistivity of 6.6 × 10−4 Ω cm which shows metallic type of conduction. Our analysis reveals that the Mott’s variable range hopping model governs the insulating behavior in the 6 nm film whereas the 2D weak localization (WL) phenomena is appropriate to explain the electron transport in the thicker Ga:ZnO films. Magnetoresistance study further confirms the presence of strong localization in 6 nm film while WL is observed in 20 nm and above thicker films. From the density functional calculations, it is found that due to surface reconstruction and Ga doping, strong crystalline disorder sets in very thin films to introduce localized states and thereby, restricts the donor electron mobility.
Biological enzyme treatment of starch-based lithium-ion battery silicon-carbon composite
Authors: Wei Runhong , Xu Ruhui , Zhang Keyu , Liang Feng , Yao Yaochun
Published: November 2020

Silicon/carbon composites have the disadvantages of large volume expansion and high cost, which limits their commercial application. In this study, green and economic starch was used to prepare porous starch (PS) under the action of enzymes, and then nano-silica was embedded in the PS. A PS based carbon/silicon/carbon composite was prepared by coating and carbonizing the starch slurry, which can alleviate the volume expansion of silicon. The results show that the anode composite material with 20% silicon content has a high initial capacity of 869 mAh g−1 and an initial Coulombic efficiency of 66% at 0.2 A g−1, and the specific capacity is maintained 450 mAh g−1 after 100 cycles. When the silicon content reaches 30%, the reversible capacity of the composite is 1490 mAh g−1 at a current density of 0.2 A g−1, and the capacity remains 850 mAh g−1 after 100 cycles. Its excellent properties and stability are attributed to the abundant porosity of the carbon in the starch derived layer, which improves the structural stability and electrochemical kinetics. This method provides a reference for the sustainable and environmental protection of lithium-ion battery anode materials.
Improved chemical precipitation prepared rapidly NiCo2S4 with high specific capacitance for supercapacitors
Authors: Tang Jibin , Huang Wanxia , Lv Xiang , Shi Qiwu
Published: November 2020

In this work, rapid chemical precipitation assisted annealing method is used to prepare flower-like NiCo2S4. And the flower-like structure after polyethylene glycol (PEG) modification yields an excellent specific capacitance (2198.9 F g−1 at 1 A g−1). And an asymmetric supercapacitor assembled with NiCo2S4 (PEG-modified) and activated carbon (AC) shows an energy density of 38.2 Wh kg−1 at 400 W kg−1, and outstanding stability (80% remained after 3000 cycles at 5 A g−1). Benefited by a larger specific surface area and suitable pore size of the aggregate structure, the specific capacitance of prepared NiCo2S4 is increased by about 2 times. This uncomplicated preparation method is proved to be suitable for NiCo2S4 with a high specific capacitance of supercapacitors.
Characterization of MOCVD regrown p-GaN and the interface properties for vertical GaN power devices
Authors: Fu Kai , Qi Xin , Fu Houqiang , Su Po-Yi , Liu Hanxiao , Yang Tsung-Han , Yang Chen , Montes Jossue , Zhou Jingan , Ponce Fernando A , Zhao Yuji
Published: November 2020

p-type gallium nitride (GaN) layers were regrown on etched surfaces on free-standing GaN substrates by metalorganic chemical vapor deposition with different growth rates by adjusting trimethylgallium flow rates. The roughness of the samples increases almost linearly with the growth rate, with an increase rate of 0.6 nm (μm h−1) −1. The screw dislocation density of the samples increases significantly when the growth rate is higher than 0.5 μm h
−

1. When the magnesium (Mg) doping concentration is higher than 7.0 × 1019 cm−3, transmission electron microscopy images clearly show the regrowth interfaces, and Mg precipitate occur in high-doping p-GaN layers. Under the same bis(cyclopentadienyl)magnesium (Cp2Mg) flow rate, the Mg doping concentration decreases with the growth rate. The samples with different growth rates show different electroluminescence spectra. The emission peak at 2.8 eV is due to the transition from the deep donor level to the Mg acceptor level. And the intensity of this peak drops with increasing growth rate due to reduction of Mg acceptors. Transitions related to defect levels appears with increasing growth rate due to an increased screw dislocation density.
Miniaturized ultra-narrowband HTS linear phase filter with CQ units sharing quarter-wavelength resonators
Authors: Zhou Liguo , Long Zhihe , Feng Quanyuan , Di Zhixiong
Published: November 2020

This paper proposes a method for designing a miniaturized ultra-narrowband high-temperature superconducting (HTS) linear phase filter based on the resonator-shared cascaded quadruplet (CQ) units constructed by the quarter-wavelength microstrip line. Two types of CQ unit with different coupling configurations are utilized to introduce transmission zeros and realize the linear phase. The introduction of transmission zeros increases the transition band roll-off rate, and the in-band group delay characteristic is improved through the phase compensation. The number of resonators and the filter size further decrease by sharing a resonator between two adjacent CQ units. Finally, a ten-order compact ultra-narrowband linear phase HTS filter with three CQ units is designed to demonstrate the feasibility. The central frequency of the filter is 450 MHz with the fractional bandwidth of 2.22%, and the dimension is 38.7 mm × 12.5 mm (0.141λ
g0 × 0.047λ
g0, λ
g0 is the guided wavelength at the central frequency f
0). The measured results show an excellent performance in the insertion loss, the out-of-band rejection, the return loss, and the passband selectivity. Moreover, the bandwidth with a group delay ripple within 30 ns occupies 70% of the entire passband, highlighting the linear phase feature. In addition, the first parasitic passband is located at 3.8 times of the fundamental frequencies. The test results are in good agreement with the simulated ones.
Effect of high- or low-speed fluctuations on the small-scale bursting events in an active control experiment*
Authors: Cui Xiao-Tong , Jiang Nan , Tang Zhan-Qi
Published: November 2020

Active control of a fully developed turbulence boundary layer (TBL) over a flat plate has been investigated with a statistical view. The piezoelectric (PZT) oscillator is employed to produce periodic input into the inner region of the TBL. A wall probe is fixed upstream of the oscillator to identify the high- or low-speed fluctuations as the detecting signals. Then, the impact of the detecting signals on the small-scale bursting process is investigated based on the data acquired by the traversing probe downstream of the oscillator. The results indicate that the small-scale bursting intensity is restrained more apparently at high-speed detecting fluctuations but less impacted at low-speed detecting fluctuations. Furthermore, the perturbed-scale fluctuations arrange the small-scale bursting process in the near-wall region. The detecting signals have an obvious impact on this arrangement, especially the high-intensity regions of the small-scale bursting events: the vibration enhances the intensity at high-speed detecting signals but weakens it at low-speed detecting signals in these regions, which gives a direct evidence on how detecting signals interfering the small-scale bursting process.
Nanostructure Fusion Region of Single Mode Fiber Coupler
Authors: Irawan Dedi , Fakhrudin Z , Mustakim  , Vebrianto Rian , Saktioto
Published: November 2020

This paper reported the characteristic of the fusion region of single mode fiber coupler. Theoretical consideration of the coupling model such as the degree of fusion and the profile of the coupling region has been investigated. The degree of fusion was inversely proportional with the separation distance between the fiber axis and the diameter of the fusion region. Fusion and elongation process also has also changed the geometrical structure of the single mode fiber. FESEM image describes that the Silicon distribution was defined as a spherical crystalline which were well-dispersed. The surface of coupling region fiber coupler has the average size of the spherical-shape crystalline varies between 300 – 500 nm. However, by increasing the elongation speed and the temperature will reduce the numbers of Si per unit area, so that the density becomes fewer. It also causes the distance between the spherical shapes become longer.
The Effect of Permanent Magnet on Dielectric Barrier Discharge (DBD) and Ozone Production
Authors: Murdiya Fri , Hamzah Amir , Firdaus  , Ramdani  , Andrio David
Published: November 2020

This paper reports the experimental results on the characteristic of ozone generator induced by a magnetic field from permanent magnets (ring PMs or combination of ring PMs and neodymium PMs) and a solid dielectric (floor ceramic/tile). Three electrode configurations (Models I, II and III) with ring PMs installed above and below the electrodes (anode and cathode of parallel plane type) were designed to examine the performance of an ozone generator. In addition, several small neodymium permanent magnets (neoPMs) were attached to the anode electrode for initiating plasma in the air gap. 9 ceramics trademarks were used in this study as a solid dielectric, among which 4 ceramics (i.e. platinum brand ceramics made in Indonesia of numbers 4 and 7 and granite types of numbers 8 and 9) produced good plasma. The intensity of the light emitted by plasma in the gap, plasma position, relationship of current and voltage and amount of ozone production were measured experimentally. It is shown that the addition of PMs above and below the electrode greatly affects the performance of the ozone generator by the effect of the magnetic field.
Design of Straight Motion Experiment using Electric Motor Ticker Timer Based on Microcontroller
Authors: Ali Riri Hardiyanti , Rahmad M. , Islami Nur , Azizahwati  , Syafii Muhammad
Published: November 2020

Most school experiment tools are limited and successful abstract concepts and unsuccessful ones become difficult to learn. Therefore we need an experiment to see the facts of the concept of straight motion become real. The purpose of this study is to discuss an experimental device using arduino uno motion to calculate the speed, distance, time and acceleration that has been obtained by an object. The method used is R & D research and development, but only tests on product design. The results showed that this program was able to simulate the concept of straight motion through cooperation between the Arduino program with sensors that work to calculate the expected physical quantities well. 97% with a very high degree of accuracy. As for the empirical test in obtaining an accuracy score of 93% with a high degree of accuracy. Thus this tool has been able to produce the concept of straight motion and has reached accuracy.
Effect of Chemical Activation on the Physical Properties of Activated Carbon from Banana Empty Fruit Bunches as Heavy Metal Adsorbent
Authors: Awitdrus  , Manulang Rita Kartini , Agustino  , Saktioto  , Iwantono  , Syahputra Romi Fadli , Farma Rakhmawati
Published: November 2020

Heavy metal pollution was a headline issue for environmental degradation, both in water and soil environments. Reducing efforts of heavy metal can be carried out through the green system, such as activated carbon from agriculture waste. This paper investigates the properties of activated carbon from banana empty fruit bunches (BEFBs) for heavy metal adsorption. The activated carbon was produced using chemical activation under microwave-assisted. Potassium hydroxide (KOH) is used as an activating agent for concentrations of 2, 3, and 4 M, each sample denoted AC-2M, AC-3M, and AC-4, respectively. The microwave irradiation was performed by a commercial microwave oven with output power up to 630 W for 15 minutes. X-ray diffraction characterization result shows the lower stack length Lc occurs in a sample of AC-2M with a value of 10.966. The surface morphology of all samples shows the presence of non-uniformed pores. The EDX analysis reveals that carbon content of AC-2M is higher than other samples up to 78.86%, while the oxygen is lower (11.87%). FTIR spectrum shown that the activated carbon from BEFBs contain functional groups of C-H, C=C, C-C, C-OH, and CH2 at wavenumber 2887 cm−1, 2360.97 cm−1, 2339.5 cm−1, 1573 cm−1, 1393.63 cm−1, and 998.21 cm−1, respectively. As the best sample, AC-2M shows higher heavy metal adsorption as much as 87.41% for Pb and 62.35% for Cu.
Smart Box Development for Food Storage with PCI-Based Temperature PID Control
Authors: Nugroho Andi , Setiadi Rahmondia Nanda , Umar Lazuardi
Published: November 2020

Temperature measurement with a control system aims to improve the quality of automation processes in the field of instrumentation, automatic systems and especially food production. The primary function of the control system is to maintain predetermined or changeable variables under specified conditions. The control system is determined by three factors, namely, process variables, controller variables and manipulated variables. In this study, the temperature response was measured in an acrylic box with a size of 30×30×20 cm3 using a PT100 sensor. The temperature response was verified with a PID control system integrated with LabVIEW software and acquired by a PCI 6221 card. The PT100 sensor calibration with the Voltcraft digital temperature shown a linear relationship. The results of the temperature response test with the PI system produced P and I parameters of 9.03 and 2.7 min, respectively, while in the PID system the P, I and D parameters were 13.2, 6.2 min and 0.2 min, respectively. The response of the control system with the PI type is more stable and consistent than the PID type. Based on the results obtained, the temperature control process using a PI or PID control system with a TD value of 0 is more recommended.
Isolation Beauveria Bassiana Vuill. Entomopathogen Local From Plant Agriculture Rhizosphere in Riau Province, Indonesia with Insect Bait Tenebrio Molitor Larvae
Authors: Hapsoh  , Salbiah D , Dini I R
Published: November 2020

Beauveria bassiana is an entomopathogen that has the ability to control agricultural crop pests. The purpose of this study was to find local B. bassiana from various rhizosphere of agricultural plants in Riau Province, Indonesia using insect baiting techniques. Isolation is carried out in several rhizosphere in plants such as oil palm, chili and rice. The results showed that isolate B. bassiana from oil palm plantations showed a faster time of infection in the test larvae of 3 days and 100% mortality, time to grow on PDA medium 2 days and conidia density 4.87 × 107 con/ml.
Microwave-Assisted Synthesis, Antioxidant and Toxicological Evaluation of a Hydrazone, 1-(4-chlorobenzylidene)-2-phenylhydrazine
Authors: Afriana N , Frimayanti N , Zamri A , Jasril J
Published: November 2020

Hydrazone is an imine-derived compound that has various biological activities such as anticancer, antitumor, antioxidant, antimicrobial, and antidepressant. Antioxidants play an important role in removing oxidants and preventing cell damage and the toxicity of a compound is one of the parameters in drug discovery, especially anticancer. In this work, a hydrazone, 1-(4-chlorobenzylidene)-2-phenylhydrazine has been synthesized under microwave irradiation and evaluated for its antioxidant activity by DPPH assay. The toxicity of this compound was evaluated by Brine Shrimp Lethality Test (BSLT) for pre-screening of anticancer drugs. The compound was elucidated for its structure using UV-Vis, FTIR, GC-MS, 1D, and 2D NMR spectrometers. Based on the toxicological evaluation using BSLT, the synthesized compound possessed a highly toxic with LC50 value of 0.018 μg/mL and has strong antioxidant activity with IC50 value of 41.33 μg/mL. These suggest that the synthesized hydrazone compound is a potential compound in the development of antioxidant and anticancer drugs.
Screening for Potential Laccase Producers from Trichoderma Strains Isolated From Riau Citrus Rhizosphere and Palm Tree Plant Parts
Authors: Pisacha Iga M , Perkasa Tengku Arief B , Amnelia Tiara , Miranti M , Puspita Fifi , Nurulita Yuana , Nugroho Titania T
Published: November 2020

The enzyme laccase has wide biotechnology applications in the textile, pulp, food and pharmaceutical industry. Fungal laccases have higher redox potential than bacterial laccases, therefore are more preferred for industry. This study aimed to screen for potential laccase producers from several Trichoderma strains isolated from citrus rhizosphere and as endophytes of palm trees. Four strains were initially screened in a qualitative colour assay on PDA supplemented with substrate indicators of laccase. The qualitative assay showed that Trichoderma asperelloides LBKURCC2 demonstrated strong laccase activity on PDA supplemented with guaiacol or 2,2’-azino-di-3-ethylbenzotiazol-6-sulfonate (ABTS). Trichoderma virens LBKURCC70, 71 and 85 showed very week laccase activity on media supplemented with guaiacol, and no detectable laccase on media supplemented with ABTS. Quantitative assays for laccase activity were performed on crude enzyme extracts from solid state fermentation systems with rice straw as the laccase inducer, and the test fungal strain as the prospective producer. From the quantitative assays it was found that T. asperelloides LBKURCC2 produced the highest laccase activity (208 ± 76 U/L). Laccase activity produced by T. virens LBKURCC70 was 19 ± 5 U/L, while there were no detectable laccase activities produced by T. virens LBKURCC71 and 85.
The Role of Minangkabau Prohibited Speech Act in Ujungbatu Community Environment, Rokanhulu District
Authors: Ningsih Asih Ria , Efendi Rinja , Arianti Rita
Published: November 2020

This research was conducted to preserve some of the oral literature one of Folklore study, namely prohibited speech act in order not to disappear in people's life and still be preserved well by the community. Especially in Minang community in Ujungbatu area of Rokan Hulu, Riau. The purpose of this study is to describe the function of the speech utterances found in Ujungbatu area. The type of this research is qualitative study by using descriptive methods. The informants of this study were three Minang people who migrated to Ujungbatu. Data is collected through observation, interview, record and data recording techniques. Based on the findings and discussion, it was found speech abstinence prohibited in Minang community in area of Ujungbatu. This study describes the functions and meanings that exist in the prohibition speech, where the category is focused on the human life cycle and the categories found consist of: (1) as a thickening of religious emotions; 2) the projected imagination a collective that comes from a person's hallucinations; 3) as an educational tool for children or adolescents; 4) reasonable explanation.
Development of Static and Kinetic Friction Coefficient Experiment Device Based on Arduino Uno
Authors: Pramudya Clara Tarania , Islami Nur , Azizahwati  , Rahmad Muhammad
Published: November 2020

The concept of friction makes physics more realistic. Based on research, physics education students are still experiencing misconceptions or do not understand the concept of the friction coefficient. Experimental tools commonly used in practicum have not been able to measure the coefficient of friction properly. The purpose of this research is to design a static and kinetic friction coefficient experiment that can be used in basic physics practicum. This study uses the ADDIE model which is carried out to the stage of develop or media development. The experiment was developed using the principle of sliding beams in an inclined plane by using an Arduino Uno microcontroller and sensors as a time and angle measurement device. The experiments designed to observe the effect of differences in mass and surface roughness on the friction coefficient. this device can measure the value ofμsandμksimultaneously. The time measurement precision value of the tool is 93% and the angle measurement precision is 98.0%. The experiment succeeded in proving thatμs>μk, surface roughness affects the value of the coefficient of friction and the mass does not affect the value of the coefficient of friction.
The Relationship Of Agilityagint Crescent Kick To Persaudaraan Setia Hati Athletes In Rokan Hulu Regency
Authors: Regency Tofikin , Sinurat Ridwan
Published: November 2020

Agility is a physical condition factor that plays an important role in improving the performance of pencak silat so it must be considered carefully. The purpose of this study was to determine whether there is a relationship between agility and sickle-kicking agility in the pencak silat athletes of the Setia Hati Terate Brotherhood in Rokan Hulu Regency. This research is a type of correlational research with a sample size of 19 people and analyzed using product moment correlation. The results showed that: There is a significant relationship between agility and the crescent-kicking agility of the Persaudaraan Setia Hati Terate athletes in Rokan Hulu Regency. With theR valuecalculated (0.523) then rx1y> Rtable, namely (0.523 > 0.456).
STEM at Home: Provide Scientific Activities for Students during the Covid-19 Pandemic
Authors: Zulirfan Z , Yennita Y , Rahmad M
Published: November 2020

The various barriers to learning science using online system during the Covid-19 pandemic, do not make us as a science educators, silent. One way to keep students able to carry out scientific activities is to provide scientific projects that students can work on in their own homes. The assignment can be delivered online and teachers’ feedback can also be given online using the learning management system. This study is the phase analysis of developing Module and Kits of STEM Project at Home that can be used in online science learning bay teachers and students. The results of this needs analysis phase serve as recommendations for the next stage of research. The final result of this development research is the availability of STEM at Home Project Modules and Kits that are valid and practical for students to use in learning science during the Covid-19 pandemic or New Normal era. A total of 340 respondents consisting of grade 1, 2, and 3 junior high school students in several schools in Riau Province, Indonesia, have participated in filling out the online questionnaires. This needs analysis shows that there is a great chance that STEM project-based science learning can be carried out online by students.
The Effectiveness of Learning Tools Based on Discovery Learning That Integrates 21st Century Skills to Mathematical Critical Thinking Ability in Trigonometric Materials in High School
Authors: Putri Ade , Kartini Kartini , Yuanita Putri
Published: November 2020

This study aims to determine the effectiveness of discovery learning based learning tools that integrate 21st-century skills in trigonometric material on the mathematical critical thinking skills of students in high school. This research is a pre-experimental study with a one-group pretest-posttest design. The tools used are the syllabus, lesson plans, and student's worksheets. The learning tools used have gone through the validation process and previous practicality tests. The effectiveness test was conducted in class XI MIPA 1 SMA Babussalam Pekanbaru. In the effectiveness test stage, the researcher gave a mathematical critical thinking ability test after completing the learning using the developed device. Indicators of mathematical critical thinking skills used are interpretation, analysis, evaluation, verification and inference. The test results show that there is an increase in each indicator of critical mathematical thinking used and the percentage of students who reach the passing grade test of mathematical critical thinking skills reaches 82.14%. So it can be concluded that the learning tools developed are effective for use. The data obtained from the critical thinking skills test results were not normally distributed based on the normality test, so to find out differences in students' critical thinking skills before and after using the device, researchers used the Mann Whitney test. Based on the results of the Mann Whitney test, it is known that the mathematical critical thinking skills of students after using the device are better than before using the device with an N-Gain value of 0.70 with a high increase category.
The Design Phase of the Development Of an Electrical Installation Prototype Kit as A Medium for The Stem Project of Junior High School Students
Authors: Yennita Y , Zulirfan Z , Fakhruddin F , Azizahwati A
Published: November 2020

This research is the design phase of the research on the development of an electrical installation prototype as a STEM project for junior high school students. This simple electrical installation project requires students to apply the concepts and theories about electrical circuits they have learned. In carrying out this STEM project, students integrate STEM elements, namely science, technology, engineering, and mathematics. Therefore, this research stage aims to design a prototype kit in accordance with STEM requirements and determine the tools and materials needed for these purposes. Based on the recommendations of the analysis phase that we have carried out before, in this stage of research, we have successfully built a design for an electrical installation project kits. The design of this electrical installation kits are in the form of the overall project design, supporting components, and the flow of project work by students. We have designed the kit in such a way that it becomes a mini project in a real context that allows students to directly apply the electrical circuit concept they have learned. In this kit design, STEM education elements have been integrated, namely Science, Technology, Engineering, and Mathematics.
Development of Mechanical Energy Trial Devices in Rotation Motion Based Arduino Uno Microcontroller
Authors: Sartika Medya , Azizahwati  , Yennita  , Islami Nur , Rahmad Muhammad
Published: November 2020

This research aims to develop tools for mechanical energy experiments on rotational motion using sensors and controlled by Arduino Uno. These objectives are motivated by the learning of mechanical energy that is often taught by teachers with the lecture method and students do not understand the concept of mechanical energy which is considered abstract. The working principle of this tool is to pass marbles on a track made of iron. This tool functions to calculate the time when a marble glides with the help of a photodiode sensor and a laser diode in order to obtain the value of translational kinetic energy, rotational kinetic energy and potential energy. This research was conducted at the Laboratory of Physics Education FKIP Riau University. The method used in this research is the Research and Development method and uses empirical test data analysis. Based on measurements of the average time obtained 0.0834 seconds and obtained an accuracy level of 0.9417 which can be categorized as very accurate. This mechanical energy experiment tool succeeded in proving mechanical energy obtained from the amount of potential energy, translational kinetic energy and rotational kinetic energy is constant.