bluuebunny/crossref_metadata_2025 huggingface dataset:
An introduction to fractal uncertainty principle
Authors: Dyatlov Semyon
Published: August 2019

Fractal uncertainty principle states that no function can be localized in both position and frequency near a fractal set. This article provides a review of recent developments on the fractal uncertainty principle and of their applications to quantum chaos, including lower bounds on mass of eigenfunctions on negatively curved surfaces and spectral gaps on convex cocompact hyperbolic surfaces.
Development of an X-ray tube with two selective targets modulated by a magnetic field
Authors: Jin Limin , Jia Wenbao , Hei Daqian , Zhang Xinlei , Zhao Lei
Published: August 2019

An energy-selective X-ray tube based on a magnetically controlled method is proposed here. An X-ray tube with two selective targets, modulated by a magnetic field, was developed for the X-ray fluorescence (XRF) analysis of multielement samples. The X-ray tube was small (20 cm length × 4 cm width) and had low power, being operated at 20 W (20 kV, 1 mA). It contained a thermionic cathode and two targets [copper (Cu) and chromium (Cr)] mounted on the anode. The electron beam was drifted by a modulated magnetic field to bombard either the Cu or Cr targets and so produce the required emission spectrum. Particle dynamics analysis software was used to simulate the particle tracking of the X-ray tube. The focal spot on the anode was successfully drifted, and a focal spot at 2 × 2.3 mm2 was obtained with a pinhole camera method. The XRF analysis of a standard sample (a mixture of Fe2O3 and CaCO3) was measured by a silicon drift detector. When the bombarding target was changed from Cu to Cr, the characteristic calcium (Ca) X-rays that were detected were twice as strong as those of iron (Fe), but they had a similar excitation efficiency. It was demonstrated that this X-ray tube can provide fast exchangeable X-rays for XRF analysis by modulating the magnetic field intensity and can be further improved by optimizing the structure for alternative applications.
Gravity and rheotaxis based sperm sorting device employing a cam-actuated pipette mechanism
Authors: Kang Hyeongseok , An Taeyoung , Lee Dongkyu , Kim Byungkyu
Published: August 2019

Until now, a swim-up or microchip-based method has been mainly utilized for separating normal sperm for use in assisted reproductive technology. However, it requires excessive sorting time due to preprocessing and collects a limited number of motile sperms. To improve this process, we propose a gravity-fed high motility sperm sorting device that utilizes the rheotaxis of sperm, which minimizes separation time and improves throughput. The device features a mesoscale microfluidic channel to maximize the throughput, and an outlet at the bottom is configured to control the fluid velocity in the channel by using gravity. To control and automate semen injection and suction of the sorted sperm, a pipette controller using a cam was fabricated. After constructing the system, a sorting experiment was performed using canine semen to confirm the separation efficiency. After injecting the semen in the channel, the delay time between injection and suction was measured and the relative improvement of the index of motility was investigated according to measured delay time. As a result of repeated experiments, it was confirmed that the highest improvement was obtained at a delay time of 80 s, and the mean velocity, %motility, MI, and motile sperm rates were improved by 8.94%, 32.58%, 35.48%, and 21.99%, respectively.
Numerical and experimental study of the motion of a sphere in a communicating vessel system subject to sloshing
Authors: Zamora Esteban , Battaglia Laura , Storti Mario , Cruchaga Marcela , Ortega Roberto
Published: August 2019

The purpose of this work is twofold: to present a computational strategy to simulate the dynamics of a rigid sphere during water sloshing and to validate the model with original experimental data. The numerical solution is obtained through the coupling between a two-fluid Navier-Stokes solver and a rigid solid dynamics solver, based on a Newton scheme. A settling sphere case reported in the literature is first analyzed to validate the numerical strategy by ascertaining the settling velocity. In addition, an experiment is carried out based on a sphere submerged into a communicating vessel subjected to sloshing. Experimental data are captured using image processing and statistically treated to provide sphere dynamics quantitative information. The effects of different classical models used to describe drag coefficients, added mass, and wall effects are considered in the study to evaluate their influence on the results. The numerical model provides results that are consistent with the physical data, and the trajectory analysis shows good agreement between the simulations and the experiments.
Saturated film boiling over a circular cylinder subjected to horizontal cross-flow in the mixed regime
Authors: Singh Nikhil Kumar , Premachandran B.
Published: August 2019

Film boiling over a circular cylinder in a horizontal cross-flow of saturated liquid is studied in the mixed regime that is characterized by a combined influence of buoyancy and flow inertia at low magnitudes of the Froude number (Fr). Liquid-vapor interface evolution and the ensuing vapor wake dynamics together with heat transfer have been determined through a computational framework developed for phase change problems on two-dimensional unstructured grids using a coupled level set and volume of fluid interface capturing method. While the quasisteady nature of ebullition cycle is gradually lost as Fr increases, the effect of cross-flow orientation with respect to gravity is shown to be nontrivial in the mixed regime. A direct consequence of the orthogonal gravity and flow fields is an anomalous impairment of heat transfer with an increase in cross-flow velocity under certain conditions, which is discussed in detail. Simultaneously, the film boiling behavior as influenced by several other hydrodynamic and thermal parameters is also ascertained. The interplay between buoyancy and inertia is further highlighted while discussing the interdependent liquid and vapor wake characteristics in the mixed regime with horizontal cross-flow. The liquid wake behavior is shown to result not only from the bluff body geometry but also the instantaneous vapor wake profiles, with the wall superheat affecting the time scale of wake interaction. Finally, a reduction factor (ξ) is proposed and determined as a function of the Froude number, which is used in conjunction with a correlation for upward cross-flow film boiling to predict the heat transfer.
The reduced Hartree-Fock model with self-generated magnetic fields
Authors: Gontier David , Lahbabi Salma
Published: August 2019

We study the well-posedness of the reduced Hartree-Fock model for molecules and perfect crystals when taking into account a self-generated magnetic field. We exhibit a critical value αc > 0 such that if the fine structure constant α is smaller than αc, then the corresponding system is stable, whereas if α is greater than αc, it is unstable. We give an explicit characterization of αc as a minimization problem over the set of zero-modes, and we prove that the critical values for the molecular case and the periodic case coincide. Finally, we prove the existence of minimizers when the system is neutral or positively charged.
Surface structures of single-crystal graphene on Cu/Ni(111) and Ge(110) substrates studied by scanning tunneling microscopy
Authors: Zhu Hailong , Cui Fenwei , Zhang Xuefu , Ma Ni , Hu Xudong , Di Zengfeng , Xie Xiaoming , Li Ang
Published: August 2019

The success in the synthesis of wafer-size single-crystal graphene enables a tremendous breakthrough in the development of graphene-based devices. Understanding the growth mechanism is essential for the design of suitable substrates to meet the demand of various applications. Here, we investigate the detailed growth process of the monolayer single-crystal graphene on Cu/Ni(111) and Ge(110) surfaces using scanning tunneling microscopy. The (3×3)R30° surface structure on Cu/Ni(111) and 1 × 1 atomic structure on Ge(110) are found to match the graphene lattice along the armchair direction. These specific atomic arrangements dictate the quasiepitaxial nature of graphene growth on both substrates despite their apparent differences in native lattice geometry.
A computational study of droplet-based bioprinting: Effects of viscoelasticity
Authors: Nooranidoost M. , Izbassarov D. , Tasoglu S. , Muradoglu M.
Published: August 2019

Despite significant progress, cell viability continues to be a central issue in droplet-based bioprinting applications. Common bioinks exhibit viscoelastic behavior owing to the presence of long-chain molecules in their mixture. We computationally study effects of viscoelasticity of bioinks on cell viability during deposition of cell-loaded droplets on a substrate using a compound droplet model. The inner droplet, which represents the cell, and the encapsulating droplet are modeled as viscoelastic liquids with different material properties, while the ambient fluid is Newtonian. The model proposed by Takamatsu and Rubinsky [“Viability of deformed cells,” Cryobiology 39(3), 243–251 (1999)] is used to relate cell deformation to cell viability. We demonstrate that adding viscoelasticity to the encapsulating droplet fluid can significantly enhance the cell viability, suggesting that viscoelastic properties of bioinks can be tailored to achieve high cell viability in droplet-based bioprinting systems. The effects of the cell viscoelasticity are also examined, and it is shown that the Newtonian cell models may significantly overpredict the cell viability.
Realization of high luminous transmittance and solar modulation ability by thermochromic VO2-based induced transmittance filter (ITF)
Authors: Jin Jingcheng , Zhang Dongping , Liu Yi , Yang Yu , Huang Ying , Guan Huan , He Qicong , Qi Jiahua , Fan Ping
Published: August 2019

This paper presents a novel thermochromic induced transmittance filter (ITF) based on VO2 films. The ITF structure enables high transmittance in the short wavelength range with wide rejection at longer wavelengths, which meets the requirements of thermochromic VO2 for the metal-insulator transition. Thus, the VO2-based ITFs are designed and fabricated based on the induced transmittance effect, and a graded-index material TiO2 is initially adopted for the simplified structure of VO2-based ITF comparing standard ITFs. The VO2-based ITF's properties are characterized systematically and compared with those of VO2 films. Favorable results of crystallinity, surface roughness, hydrophobicity, the thermal hysteresis width, and pleasant appearance color are achieved in these VO2-based ITFs. Moreover, luminous transmittance Tlum (380–780 nm) of 48.8% and a solar modulation ability ΔTsol of 6.2% are achieved with an ideal spectrum shape in the VO2-based ITF, which provides a highly efficient solution to improve thermochromic VO2 films and related field.
Isolation solution for extreme environmental vibrations for quantum-enabling cryogenic setups installed on raised frames
Authors: Cerbin Jonah , Sochnikov Ilya
Published: August 2019

Cryogenic quantum sensing techniques are developing alongside the ever-increasing requirements for noiseless experimental environments. For instance, several groups have isolated internal system vibrations from cold heads in closed-cycle dilution refrigerators. However, these solutions often do not account for external vibrations, necessitating novel strategies to isolate the entire cryogenic systems from their environments in a particular set of raised cryostats. Here, we introduce a dual-stage external active vibration-isolation solution in conjunction with a closed-cycle dilution refrigerator that isolates it from the environment. This dual stage includes two sets of active attenuators and a customized steel tower for supporting experimental probes at heights of 3 m from the floor. Both stages achieve 20–40 dB of attenuation with the active systems engaged, corresponding to levels of vibration in the VC-G range (a standardized Vibration Criterion appropriate for extremely quiet research spaces) on the cryostat’s room temperature baseplate and the steel tower. Our unique vibration isolation solution therefore expands the applications of modern cryogenic equipment beyond exclusively quiet specialty buildings, rendering such equipment suitable for interdisciplinary, open-floor research centers.
Coupling of drift wave with dust acoustic wave
Authors: Kumar Atul , Das Amita , Kaw Predhiman
Published: August 2019

A drift wave is a prominent mode of a magnetized plasma of inhomogeneous density. It plays an important role in the transport of particles, energy, and momentum perpendicular to the ambient magnetic field. The frequency of this mode is governed by the inhomogeneity scale length and is much lower than the typical homogeneous plasma modes involving ions and electrons. In this work, the possibility of coupling of this particular mode with the low frequency modes of a dusty plasma medium is considered. The drift wave has been found to saturate at large ky (perpendicular wavenumber) in a magnetized plasma with weakly correlated dust species mainly due to the shielding by polarization drift of ions. However, when dust particles are strongly correlated, the drift wave converts into a transverse shear wave at large ky.
High-throughput automatic batching equipment for solid state ceramic powders
Authors: Shuang Shuang , Li Honghua , He Gang , Li Yong , Li Jiangtao , Meng Xiangmin
Published: August 2019

We describe the design, fabrication, and use of a ceramic bulk preparation system, applied to the very high-throughput batching and molding for solid ceramic powders. Through the principle on precise volume controlling of powder materials, up to 100 ceramic block samples with maximum 6 components could be prepared in one time through 100 channels with Φ5 × 5 mm forming molds. The automatic control stage has been built to fill the target powder in a limited size and discrete small volume range. Here, we have designed a mechanical structure and software program so that rotary silo powder feeding amount could be controlled at 5–100 ml/time and the feeding precision can reach 0.005 g. Finally, the equipment is verified by preparing several infrared ceramic samples of different components.
Spin-orbit coupling from a two-component self-consistent approach. I. Generalized Hartree-Fock theory
Authors: Desmarais Jacques K. , Flament Jean-Pierre , Erba Alessandro
Published: August 2019

Formal and computational aspects are discussed for a self-consistent treatment of spin-orbit coupling within the two-component generalization of the Hartree-Fock theory. A molecular implementation into the CRYSTAL program is illustrated, where the standard one-component code (typical of Hartree-Fock and Kohn-Sham spin-unrestricted methodologies) is extended to work in terms of two-component spinors. When passing from a one- to a two-component description, the Fock and density matrices become complex. Furthermore, apart from the αα and ββ diagonal spin blocks, one has also to deal with the αβ and βα off-diagonal spin blocks. These latter blocks require special care as, for open-shell electronic configurations, certain constraints of the one-component code have to be relaxed. This formalism intrinsically allows us to treat local magnetic torque as well as noncollinear magnetization and orbital current-density. An original scheme to impose a specified noncollinear magnetization on each atomic center as a starting guess to the self-consistent procedure is presented. This approach turns out to be essential to surpass local minima in the rugged energy landscape and allows possible convergence to the ground-state solution in all of the discussed test cases.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: August 2019

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
Studying the dynamics of a rigid body immersed in a sloshing fluid
Authors: Bandari Anashe
Published: August 2019

Researchers modeled the motion of a rigid sphere in a chaotic fluid and the coupling between the two bodies.
CPEB3 inhibits translation of mRNA targets by localizing them to P bodies
Authors: Ford Lenzie , Ling Emi , Kandel Eric R. , Fioriti Luana
Published: August 2019

Significance

Deciphering how cells regulate compartmentalization is critical for our understanding of local protein synthesis-dependent mechanisms, such as learning and memory. One way to achieve compartmentalization is by means of liquid–liquid phase separation, which results in the formation of membraneless organelles such as P bodies. In this study, we investigated how the cell regulates the inhibitory effect of the translation regulator cytoplasmic polyadenylation element-binding protein 3 (CPEB3), by means of small ubiquitin-like modifier (SUMO)ylation and localization to P bodies. Our findings on the role of SUMO as a critical mediator of CPEB3 phase separation might be relevant also in the context of the aberrant phase separation that characterizes other RNA-binding proteins implicated in neurodegenerative diseases, such as FUS (fused in sarcoma) and TDP-43 (TAR DNA binding protein 43) in ALS (amyotrophic lateral sclerosis).
Nucleosome positions alone can be used to predict domains in yeast chromosomes
Authors: Wiese Oliver , Marenduzzo Davide , Brackley Chris A.
Published: August 2019

Significance

DNA is packaged into chromosomes, which are further organized into domains: Regions of the genome which are more likely to self-interact. Domains have been observed in species ranging from bacteria to humans and are thought to play an important role in gene regulation. Yet the mechanisms of domain formation are not fully understood. Here we use computer simulations to investigate domain formation in yeast. Our model reproduces the experimentally observed domains using only nucleosome positioning information as an input, implying that (unlike in higher eukaryotes) domain boundary locations are largely determined at this level. Our results reveal how irregular nucleosome spacing impacts the 3D chromosome organization, pointing to a direct link between nucleosome positioning and genome regulation at the large scale.
Structure and dynamics of G protein-coupled receptor–bound ghrelin reveal the critical role of the octanoyl chain
Authors: Ferré Guillaume , Louet Maxime , Saurel Oliver , Delort Bartholomé , Czaplicki Georges , M’Kadmi Céline , Damian Marjorie , Renault Pedro , Cantel Sonia , Gavara Laurent , Demange Pascal , Marie Jacky , Fehrentz Jean-Alain , Floquet Nicolas , Milon Alain , Banères Jean-Louis
Published: August 2019

Ghrelin plays a central role in controlling major biological processes. As for other G protein-coupled receptor (GPCR) peptide agonists, the structure and dynamics of ghrelin bound to its receptor remain obscure. Using a combination of solution-state NMR and molecular modeling, we demonstrate that binding to the growth hormone secretagogue receptor is accompanied by a conformational change in ghrelin that structures its central region, involving the formation of a well-defined hydrophobic core. By comparing its acylated and nonacylated forms, we conclude that the ghrelin octanoyl chain is essential to form the hydrophobic core and promote access of ghrelin to the receptor ligand-binding pocket. The combination of coarse-grained molecular dynamics studies and NMR should prove useful in improving our mechanistic understanding of the complex conformational space explored by a natural peptide agonist when binding to its GPCR. Such information should also facilitate the design of new ghrelin receptor-selective drugs.
Cell phenotypic plasticity requires autophagic flux driven by YAP/TAZ mechanotransduction
Authors: Totaro Antonio , Zhuang Qiuyu , Panciera Tito , Battilana Giusy , Azzolin Luca , Brumana Giulia , Gandin Alessandro , Brusatin Giovanna , Cordenonsi Michelangelo , Piccolo Stefano
Published: August 2019

Significance

We describe the convergence of autophagy with YAP/TAZ, 2 highly related transcriptional regulators playing essential roles in cell plasticity for tissue regeneration and cancer. We show that a key event in autophagy, the fusion of autophagosomal vesicles with lysosomes, is transcriptionally regulated by YAP/TAZ. At least in part, this is mediated by the YAP/TAZ target Armus, a protein of the RAB-GAP family. Consistently with YAP/TAZ being patterned by mechanical signals, we found that cellular mechanics, dictated by the physical properties of the ECM, potently regulate autophagy efficiency. The connection described here is crucial for YAP-mediated reprogramming of normal cells into stem-like cells and of benign tumor cells in cancer stem cells. Thus, nuclear reprogramming must go hand in hand with autophagy-mediated cytoplasmic restructuring.
Rapid weight loss influences the physical, psychological and biological responses during a simulated competition in national judo athletes
Authors: Isacco Laurie , Degoutte Fabrice , Ennequin Gaël , Pereira Bruno , Thivel David , Filaire Edith
Published: August 2019

The effect of rapid energy restriction‐induced weight loss on judo‐related performance remains unclear, and there is a paucity of information regarding the influence of the fight successions during competition. Thus, the aim of this study was to compare the cumulative effect of judo fights on physical performance, biological and psychological profiles, of national judo competitors with vs without rapid weight loss. After one month of weight maintenance (Baseline), 20 subjects were randomly divided into two groups the week before a simulated competition: (i) a Weight Loss group (WL; weight loss ≥ 3% of body mass); (ii) a Weight Stable group (WS). The simulated competition was composed of five fights (F1 to F5) separated by 30 min rest. Anthropometric assessments were performed at baseline and on the morning of the simulated competition (T0). Psychological, biological and physical assessments (maximal handgrip strength, upper limb anaerobic capacity) were performed at T0 and after each fight. The variation of body mass between baseline and T0 was significantly different between groups (+1.2% vs −3%; p < .01). The dimensions of the Profile of Mood State questionnaire, the rate of perceived exertion, ammonia, urea and free fatty acid concentrations, maximal strength and time sustained at maximal strength showed a significant group x time interaction at F4 and F5. The study shows that cumulative fights lead to uncoupled responses in physical, psychological and biological parameters in judo competitors who underwent or not rapid weight loss. Specific recovery strategies in terms of nutrition and active recovery should be considered.
50 years change in urban land use and ecological planning globally in the era of design with nature
Authors: Douglas Ian
Published: August 2019

Ian McHarg’s 1969 book,
Design with Nature
, was grounded in earlier good practice, especially the European vision of fitting cities into the regional landscape and carrying thorough surveys before planning commenced. The book emerged in the wake of publications that worried about the ability of the earth to support expanding populations and their growing impact on the environment. McHarg argued that ecological design should follow planning based on detailed site information. Although McHarg advised many urban authorities in the USA and other countries, especially in Africa, Asia and Europe, and his ideas had influenced some British new towns, they had little attention in the planning of Milton Keynes, England’s largest new urban settlement, where the initial geological surveys were inadequate, but a successful large tree-planting program has created a “city in the forest.” McHarg was however closely involved in planning the Nigerian Capital city, Abuja, but his sound master plan was ill-equipped to provide for a nation undergoing post-conflict rebuilding and a local population more concerned with access to land than ecological planning. Nonetheless, McHarg helped us to promote, protect, and preserve urban green spaces. Although teams from different disciplines now work well together, the integrated thinking advocated by McHarg remains sometimes in short supply in local practice.
Strong Superadditive Deficit of Coherence and Quantum Correlations Distribution*
Authors: Liu Si-Yuan , Wu Feng-Lin , Zhang Yao-Zhong , Fan Heng
Published: August 2019

The definitions of strong superadditive deficit for relative entropy coherence and monogamy deficit of measurement-dependent global quantum discord are proposed. The equivalence between them is proved, which provides a useful criterion for the validity of the strong superadditive inequality of relative entropy coherence. In addition, the strong superadditive deficit of relative entropy coherence is proved to be greater than or equal to zero under the condition that bipartite measurement-dependent global quantum discord (GQD) does not increase under the discarding of subsystems. Using the Monte Carlo method, it is shown that both the strong superadditive inequality of relative entropy coherence and the monogamy inequality of measurement-dependent GQD are established under general circumstances. The bipartite measurement-dependent GQD does not increase under the discarding of subsystems. The multipartite situation is also discussed in detail.
Influence of Debye Plasma on the KLL Dielectronic Recombination of H-Like Helium Ions*
Authors: Zhang Deng-Hong , Xie Lu-You , Jiang Jun , Dong Chen-Zhong
Published: August 2019

Using the Debye shielding model, the effects of plasma shielding on the dielectronic recombination processes of the H-like helium ions are investigated. It is found that plasma shielding causes a remarkable change in the Auger decay rate of the doubly excited 2p
2
3
P
2 state. As a result, the dielectronic recombination cross sections from the doubly excited 2p
2
3
P
2 state increases with the decreasing Debye shielding length.
Wavelength-Locked 878.6 nm In-Band Pumped Intra-Cavity 2.1 μm Optical Parametric Oscillator*
Authors: Wu Shuang , Yu Yong-Ji , Li Yue , Wang Yu-Heng , Liu Jing-Liang , Jin Guang-Yong
Published: August 2019

We report herein a high-power folded intra-cavity 2.1 μm optical parametric oscillator (ICOPO) which is the first example of an ICOPO that utilizes a wavelength-locked 878.6 nm in-band pumped Nd:YVO4 laser as the pump source. The thermal effect of PPMgLN crystal and the divergence angle of the incident laser are considered comprehensively to determine the 2128 nm degenerate temperature. In the experiment, the functions of different output coupler transmittances and different repetition rates on the parametric laser output power are studied, respectively. The temperature versus parametric laser output power in an in-band pumped non-wavelength-locked 880 nm laser diode (LD) and in a wavelength-locked 878.6 nm LD is compared. A maximum output power of 5.87 W is obtained at the pump power of 56.9 W when the repetition rate is 80 kHz. The corresponding conversion efficiency is 14.55%, with a linewidth of 73.65 nm and pulse width of 3.62 ns. The wavelength-locked 878.6 nm LD in-band pumping technology can stabilize the 2.1 μm laser output power of Nd:YVO4 crystal effectively in the environment of intense temperature change.
Superconductivity in Topological Semimetal θ-TaN at High Pressure*
Authors: Jia Ya-Ting , Zhao Jian-Fa , Zhang Si-Jia , Yu Shuang , Dai Guang-Yang , Li Wen-Min , Duan Lei , Zhao Guo-Qiang , Wang Xian-Cheng , Zheng Xu , Liu Qing-Qing , Long You-Wen , Li Zhi , Li Xiao-Dong , Weng Hong-Ming , Yu Run-Ze , Yu Ri-Cheng , Jin Chang-Qing
Published: August 2019

Recently, θ-TaN was proposed to be a topological semimetal with a new type of triply degenerate nodal points. Here, we report studies of pressure dependence of transport, Raman spectroscopy and synchrotron x-ray diffraction on θ-TaN up to 61 GPa. We find that θ-TaN becomes superconductive above 24.6 GPa with T
c
at 3.1 K. The θ-TaN is of n-type carrier nature with carrier density about 1.1 × 1020/cm
3
at 1.2 GPa and 20 K, while the carrier density increases with the pressure and saturates at about 40 GPa in the measured range. However, there is no crystal structure transition with pressure up to 39 GPa, suggesting the topological nature of the pressure induced superconductivity.
Advances in new generation diluted magnetic semiconductors with independent spin and charge doping
Authors: Zhao Guoqiang , Deng Zheng , Jin Changqing
Published: August 2019

As one branch of spintronics, diluted magnetic semiconductors (DMSs) are extensively investigated due to their fundamental significance and potential application in modern information society. The classical materials (Ga,Mn)As of III–V group based DMSs has been well studied for its high compatibility with the high-mobility semiconductor GaAs. But the Curie temperature in (Ga,Mn)As film is still far below room temperature because the spin & charge doping is bundled to the same element that makes the fabrication very difficult. Alternatively, the discovery of a new generation DMSs with independent spin and charge doping, such as (Ba,K)(Zn,Mn) 2As2 (briefly named BZA), attracted considerable attention due to their unique advantages in physical properties and heterojunction fabrication. In this review we focus on this series of new DMSs including (I) materials in terms of three types of new DMSs, i.e. the " 111”, " 122” and " 1111” system; (II) the physical properties of BZA; (III) single crystals & prototype device based on BZA. The prospective of new type of DMSs with independent spin and charge doping is briefly discussed.
Amorphous magnetic semiconductors with Curie temperatures above room temperature
Authors: Chen Na , Fang Kaixuan , Zhang Hongxia , Zhang Yingqi , Liu Wenjian , Yao Kefu , Zhang Zhengjun
Published: August 2019

Recently, amorphous magnetic semiconductors as a new family of magnetic semiconductors have been developed by oxidizing ferromagnetic amorphous metals/alloys. Intriguingly, tuning the relative atomic ratios of Co and Fe in a Co-Fe-Ta-B-O system leads to the formation of an intrinsic magnetic semiconductor. Starting from high Curie-temperature amorphous ferromagnets, these amorphous magnetic semiconductors show Curie temperatures well above room temperature. Among them, one typical example is a p-type Co28.6Fe12.4Ta4.3B8.7O46 magnetic semiconductor, which has an optical bandgap of ~2.4 eV, room-temperature saturation magnetization of ~433 emu/cm3, and the Curie temperature above 600 K. The amorphous Co28.6Fe12.4Ta4.3B8.7O46 magnetic semiconductor can be integrated with n-type Si to form p–n heterojunctions with a threshold voltage of ~1.6 V, validating its p-type semiconducting character. Furthermore, the demonstration of electric field control of its room-temperature ferromagnetism reflects the interplay between the electricity and ferromagnetism in this material. It is suggested that the carrier density, ferromagnetism and conduction type of an intrinsic magnetic semiconductor are controllable by means of an electric field effect. These findings may pave a new way to realize magnetic semiconductor-based spintronic devices that work at room temperature.
A rapid in vitro protocol for callus production in Piper aduncum L. propagation of East Kalimantan supplemented with gradient sucrose solutions
Authors: Kusuma R , Sudrajat  , Kartika R
Published: August 2019

Piper aduncum L. is a medicinal plant which contains important active compounds such as phenyl propanoids, lignoids and flavonoids. Furthermore, it is one of larvicidal agent against mosquitoes Aedes aegypti L. Alternative use of in vitro callus P. aduncum L. are as a substitute for medicinal raw materials and becomes one way to maintain the sustainability of germ plasm utility, which is related to its difficulties in conventional cultivation. An experiment based on saline formulation of Murashige and Skoog (MS) and Wood Plant Medium (WPM) combined with different 2,4-D and kinetin concentration was evaluated. Several conditions without plant growth regulator hormones with nodule segment explants produced good multiplication process. Inoculated micro-cutting segments of nodules were grown in media with an additional 2 mg/L of 2,4-D, 2 mg/L of kinetin and 30 g sugar produced multiplication of clear shoots and callus formation and were developed after 4 weeks of planting. Additional treatment of 60, 90, 120 g sugar showed slow growth as indicated by callus formation after 6-8 weeks of planting. Treatment of 30 g sugar showed better growth than other treatments, which triggered the survival of callus growth until 12 weeks after planting. The other treatments showed cell death after callus initiation due to browning process.
Utilization of ginger extract (Zingiber Officinale) and turmeric extract (Curcuma longa) as edible tomato-packing film
Authors: Sedyadi E , Sulistyowati A , Kusumawati M , Nugraha I , Prabawati S Y
Published: August 2019

Research on ginger extract and turmeric extract as edible tomato-packing film has been done. This study was conducted to determine the ability of both extracts in increasing the storage time of tomatoes tested by its texture and shrinkage of tomato fruit weight parameters. Research showed that the addition of ginger extract and turmeric extract into edible film able to maintain the quality and life of tomato fruit when reviewed based on 50% of shrinkage weight and 63% of texture damage. Fifty percent of shrinkage of tomato control weight occured within 45 days. Depreciation of 50% of tomato weight with edible film coating without ginger extract may increase to 48 days. Edible tomato coated with added ginger extract shrink 50% of tomato weight in 65 days, while tomato coated edible film with addition of turmeric extract experience 50% shrinkage of tomato weight in 60 days. Texture reduction of 63% in tomatoes occurred 7 days to 7.5 days with edible film coating without ginger extract, while with edible film coating with the addition of ginger extract to 12 days. While turmeric extract to 186 days.
Computational study of carbon nanotube-substituted boron-nitrogen for hydrogen storage with density functional theory method (DFT)
Authors: Anwar K , Gunawan R , N Subagyono R R D J
Published: August 2019

Computational study of pure carbon nanotube, carbon nanotubes and carbon nanotube substituted boron boron-nitrogen substituted as hydrogen storage has been done. This research was conducted using the method Density functional theory (DFT), B3LYP functional and basis set STO-3G. Substitution of boron and nitrogen atoms produce structures with lower total energy, while the boron atom substitution produces structures with higher total energy than the pure carbon nanotubes. Lowest total energy possessed by a carbon nanotube boron-nitrogen substituted by -1321 10−14 J, while nanotube pure carbon structure of -1.319 10−14 J and boron-substituted carbon nanotube of -1.314 10−14 J. The total value of lowest energy is obtained from 105 structure with the addition of molecular hydrogen.
Modelling using unified software development process (USDP) method for repository system in Mulawarman University
Authors: Hatta H R , Khairina D M , Haviluddin  , Kridalaksana A H , Maharani S , Ramadiani  , Kresnapati B
Published: August 2019

Lack of academic document storage or academic electronic-based data in Mulawarman University is the basis of this research. As a Republic Indonesia Regulation in No. 82/2012 on Electronic System and Transaction Act. 3. Therefore, Mulawarman University is required to provide electronic document or electronic-based data storage thus easy for those who need it. In this study, Unified Software Development Process (USDP) methodology as a modeling system has been implemented. Meanwhile, PHP and MySQL as a system development tool have been explored. A document storage system or website-based data called a repository information system has been created as a result of this research. Furthermore, this repository has ten types documents that can be stored and retrieved, consisting of journals, books, proceedings, articles, university regulatory, guidance, reports, course materials, letters, and other academic data for Mulawarman University.
Implementation of Wireless Sensor Network (WSN) to calculate air pollution index of Samarinda City
Authors: Rinaldi A , Natalisanto A I , Muliyono S , Said S
Published: August 2019

Environmental pollution is one of the major problems opened by the world today. The main problem of this pollution, is decreasing air quality. This decrease in air quality is caused by many things, from excessive environmental exploitations, industrial activity, energy use, until the exhaust emissions of vehicles all of which trigger into pollution problems. So far Indonesian government has purchased and use the Air Quality Monitoring Base Station to measure different types of air pollutants. However, field statistics data show that the minimum quality of air quality measuring devices in each city is not commensurate with the minimum recommended amount, ideally one base station is used for 200.000 inhabitans. In this research, we developed an integrated Wireless Sensor Network to monitor the concentration of air pollution. Implemented fifteen sensor nodes which each node contains CO and NO2 sensors to sensing from the environment. the collected data will be used to calculate the standard air pollution index of samarinda city. The data is stored in server and we can publish for public to access information throught a gadget and thing speak server.
Graph coloring for determining angklung distribution
Authors: Salindeho B M , Baskoro E T
Published: August 2019

Angklung is a traditional instrument originated from West Java, Indonesia. It is played by shaking it and each angklung can only produce one note. A set of angklungs are needed in order to produce a whole song. An angklung player can hold no more than seven angklungs because of the size of the instrument. A player also cannot hold two overlapping angklungs since shaking more than one angklung at the same time is nearly impossible. These restrictions create problems that can be modeled as mathematical problem. It is called the angklung distribution problem, which is the problem of distributing angklungs to each player based on a given song so that no player holds two or more overlapping angklungs with the least possible number of players. In this paper, we model this problem into a graph theoretical problem where we use the concept of graph coloring to solve this problem. We also develop a method to lower the number of players suggested from the graph coloring by viewing the song as an array of symbols.
Composition of Indonesia throughflow in North Sulawesi water masses and heat content
Authors: Bernawis Lamona I , Ramadhan Fauzan L , Chairuasni Luqman N , Rachmayani Rima , Putri Mutiara R
Published: August 2019

In this research the composition of water masses in the North Sulawesi (Sangihe Talaud) waters as part of the Indonesian Throughflow is investigated and analysed by using the Optimum Multi Parameter Analysis (OMP). The data used is the World Ocean Atlas data (WOA 13) in 1° x 1° latitude longitude resolution. Main data are the salinity, temperature and pressure. The Optimum Multiparameter analysis was used to calculate the percentage of each water mass contribution in the study waters. The contributions are 20-60% at 200-500 m depth for The North Pacific Intermediate Water (NPIW), 90-100%at around 0-100 meters depth for The North Pacific Subtropical Water (NPSW),100%at 900-1500 meters depth for the South Pacific Intermediate Water (SPIW)and 80-100% at 1100-1500 meters depth for TheAntartic Intermediate Water (AAIW). Surprisingly, the South Pacific Subtropical Water (SPSW) does not have any contribution and largest heat content comes from the AAIW. Magnitudes for each heat content of water types calculated in this study for NPIW, NPSW, AAIW, SPSW, and SPIW are in the range of 1.5 × 1014∼ 1.7 × 1014 J/m2, 2 × 1012∼ 9.9 × 1012 J/m2, 2.7 × 1014∼ 3.1 × 1014 J/m2, 0 ∼ 4.3 × 1011 J/m2, and 1.8 × 1014∼ 2 × 1014 J/m2, respectively. Eventhough the AAIW has the lowest temperature range but its large contribution in the waters outnumbers the warmer water masses.
Semiparametric regression based on three forms of trigonometric function in fourier series estimator
Authors: Mardianto M F F , Tjahjono E , Rifada M
Published: August 2019

The semiparametric regression is one of the three forms of regression analysis which is made up of parametric and nonparametric. While the parametric is based on linear estimator, this nonparametric component is an innovation. This research proposes all the possible trigonometric basis usually used in Fourier series as nonparametric component estimator, its advantage, which includes its ability to overcome data with oscillation patterns. This study discusses nonparametric regression based on complete and sine Fourier series. Both estimators are developed using the cosine Fourier series concept. The outputs are two estimators which are used for parametric and nonparametric components with the corresponding form in semiparametric regression. In addition, all of these can be applied in real problems, and the best estimator is determined based on the smallest GCV and MSE for an oscillation parameter which gives the highest coefficient of determination for the selected one.
A flipped-classroom pilot in a spectroscopy course for undergraduates
Authors: Montalbano V , Marinelli C
Published: August 2019

In order to promote problem-based and active learning in the physics laboratory, we designed a flipped classroom focused on the Franck-Hertz experiment. The flipped classroom approach moves course content from the classroom to homework and uses class time for engaging activities and problem solving. This constructivist approach to teaching is an effective means of student-centred collaboration and it can promote active learning, enhance the critical thinking and obtain the maximum use of student-faculty time together. We report preliminary results of the flipped classroom approach to a laboratory and how it worked in the context of a small group of students in a physics course.
Teaching General Relativity with sector models: the field equations
Authors: Kraus U , Zahn C
Published: August 2019

The field equations of the general theory of relativity state the connection between spacetime curvature and matter, often summarized as “matter curves spacetime”. In this contribution we analyze the structure of the field equations from a pedagogical point of view and describe a formulation that is accessible in secondary school and undergraduate physics. This formulation of the field equations requires the concept of curvature in three dimensions and we show how this notion can be introduced using sector models. The field equations are illustrated using the black hole as an example.
Visualization of chaotic attractors in 3D as motivating tool for introductory physics course
Authors: Nagy P , Tasnádi P
Published: August 2019

It is well known that simple nonlinear systems can produce inherently unpredictable behaviour, which is called chaotic motion. Interest in the theory behind it has risen rapidly and much effort has been invested in integrating it into graduate and undergraduate curricula. However, the concepts and ideas that are appropriate for the description of these motions are very abstract and intricate. Human beings are visual creatures in nature; therefore all aids and procedures which give a visible demonstration of an abstract idea are of great value from a didactic point of view. Our paper offers the teachers a method for the demonstration of strange attractors which play a central role in the theory of chaotic systems. The images of the 2D projection of the strange attractors are well known and common, however their 3D visualisation gives a real sensation for the human brain so they are much more suitable for capturing the students’ interest. With the help of our downloadable MAPLE program the DXF files of strange attractors can be easily generated and their images can be engraved in glass. E-materials belonging to the method can be downloaded from our webpage.
Experimental problem solving: a plausible approach for conventional laboratory courses
Authors: Khaparde R
Published: August 2019

Almost every student is expected to work on a collection of experimental setups to get the desired ‘hands-on’ experience with physical systems during the conventional laboratory courses offered at colleges and universities the world over. In a number of conventional laboratory courses, the ‘minds on’ aspects and related cognitive abilities are not given their due importance, probably for a variety of valid reasons and constraints. This affects the overall learning and development of various capabilities that seems to be achievable through laboratory courses. As a plausible alternative to the traditional method of instruction, ‘experimental problem solving’ approach developed and implemented for the physics laboratory courses by the author is presented here. In this approach, students are given ‘experimental problems’ and encouraged to think and decide on several aspects and thereby perform self-guided experimental work with minimal help from the instructor. For this, each conventional experiment is presented as an experimental problem. The experimental problem solving approach thus integrates and fosters conceptual understanding, procedural understanding, experimental skills, cognitive processes, and overall problem solving ability. In this paper, the author presents details of the experimental problem solving approach and illustrates the approach with two sample experimental problems.
Game Development for Teaching Physics
Authors: Kortemeyer G
Published: August 2019

We describe two video games recently developed to teach physics concepts: “A Slower Speed of Light” was designed to teach aspects of Special Relativity, while “Kirchhoff’s Revenge” aims to teach circuit laws. Both are based on the Unity 3D platform, which allows rapid cross-platform development.
Interactive animations as a tool in teaching general relativity to upper secondary school students
Authors: Ryston M
Published: August 2019

One possible and often seen approach to teaching General Relativity are the so-called embedding diagrams. Educators are using them, sometimes perhaps even unknowingly, any time they talk about spacetime around a star being “like a rubber sheet weighed down by a bowling ball”. In this contribution we will briefly remind what these embedding diagrams are and discuss possible problems with their use. Finally, we will introduce interactive computer animations (applets) as a possible approach to overcome some of these problems.