bluuebunny/crossref_metadata_2025 huggingface dataset:
Interpretation and integration of “creating shared value” in Asia: implications for strategy research and practice
Authors: Kim Rebecca Chunghee , Saito Akira , Avvari V. Mohan
Published: April 2019

“Creating shared value” (CSV) appears on contemporary business agendas. But despite empirical evidence concerning its popularity, serious questions about the logic of CSV are raised by scholars. This paper focuses on CSV in the Asian context. Using in-depth interviews with key informants from Japan, Korea, and India, we employ a strategy-as-practice approach and develop propositions related to CSV in Asia. We identify three characteristics of Asian business practices that shape CSV in Asia: a survival sense, a strong ethical stance, and business-in-society dynamics. Finally, we introduce a preliminary framework for Asian CSV along with suggestions for future research and practice.
Neumann-Weber integral transform for complex indices
Authors: Buschle L. R. , Kurz F. T. , Schlemmer H.-P. , Ziener C. H.
Published: April 2019

Diffusion and heat equations are commonly investigated in mathematical physics and are solvable for potentials in polar coordinates with a separation into a radial and an angular equation. While the angular equation can be solved easily, a common method for solving the radial part consists in the application of the Neumann-Weber integral transform. The Neumann-Weber integral transform, however, has only been shown to be valid for real indices of Bessel functions. In this work, we generalize the Neumann-Weber transform to complex Bessel indices. The back transform then becomes dependent on zeros of Hankel functions, and we provide useful information for its numerical implementation. The results are relevant for solving diffusion equations and heat equations around cylindrical objects.
Relativistic quantum average-atom model with relativistic exchange potential
Authors: Faussurier Gérald , Blancard Christophe
Published: April 2019

We present a relativistic quantum average-atom model where bound and free electrons are treated self-consistently. We propose a relativistic exchange potential that generalizes the nonrelativistic Kohn-Sham exchange potential. The relativistic exchange potential is considered in detail. We interpolate smoothly between the nonrelativistic and ultrarelativistic limits. We neglect the correlation effect. Numerical examples are given.
Effects of nitrogen doping in amorphous carbon layers on the diffusion of fluorine atoms: A first-principles study
Authors: Park Hwanyeol , Lee Sungwoo , Kim Ho Jun , Woo Daekwang , Park Se Jun , Lee Jong Myeong , Yoon Euijoon , Lee Gun-Do
Published: April 2019

We investigated the effects of nitrogen doping in amorphous carbon layers on the diffusion of fluorine atoms based on density functional theory calculations. For N doping at both substitutional and interstitial sites, the F atom binds to the surrounding C atoms rather than the N atom during structural relaxation due to the electrostatic repulsion between N and F atoms. Furthermore, the diffusion barriers associated with the F atom passing by the N atom are extremely large (5.19 eV for substitutional N doping and 4.77 eV for interstitial N doping), primarily due to the electrostatic repulsion originating from the strong electronegativities of both atoms. The results clearly show that N doping increases the diffusion barrier of the F atom, thereby suppressing the diffusion of the F atom. The findings provide information about the role of N doping in amorphous carbon layers and yield insights for improving the fabrication processes of future integrated semiconductor devices.
Coarse-graining involving virtual sites: Centers of symmetry coarse-graining
Authors: Jin Jaehyeok , Han Yining , Voth Gregory A.
Published: April 2019

Coarse-grained (CG) models allow efficient molecular simulation by reducing the degrees of freedom in the system. To recapitulate important physical properties, including many-body correlations at the CG resolution, an appropriate mapping from the atomistic to CG level is needed. Symmetry exhibited by molecules, especially when aspherical, can be lost upon coarse-graining due to the use of spherically symmetric CG effective potentials. This mismatch can be efficiently amended by imposing symmetry using virtual CG sites. However, there has been no rigorous bottom-up approach for constructing a many-body potential of mean force that governs the distribution of virtual CG sites. Herein, we demonstrate a statistical mechanical framework that extends a mapping scheme of CG systems involving virtual sites to provide a thermodynamically consistent CG model in the spirit of the principle of maximum entropy. Utilizing the extended framework, this work defines a center of symmetry (COS) mapping and applies it to benzene and toluene systems such that the planar symmetry of the aromatic ring is preserved by constructing two virtual sites along a normal vector. Compared to typical center of mass (COM) CG models, COS CG models correctly recapitulate radial and higher order correlations, e.g., orientational and three-body correlations. Moreover, we find that COS CG interactions from bulk phases are transferable to mixture phases, whereas conventional COM models deviate between the two states. This result suggests a systematic approach to construct more transferable CG models by conserving molecular symmetry, and the new protocol is further expected to capture other many-body correlations by utilizing virtual sites.
Design optimization of a fast-neutron detector with scintillating fibers for triton burnup experiments at fusion experimental devices
Authors: Takada E. , Amitani T. , Fujisaki A. , Ogawa K. , Nishitani T. , Isobe M. , Jo J. , Matsuyama S. , Miwa M. , Murata I.
Published: April 2019

Time-resolved triton burnup studies have been carried out to estimate the behavior of alpha particles in DD fusion experimental devices. In those studies, 14 MeV neutrons emitted through DT reactions in DD plasmas should be measured selectively in the backgrounds of DD neutrons and gamma rays. For this purpose, a scintillating-fiber (Sci-Fi) based fast-neutron detector has been adapted because of its advantages such as fast response, design flexibility in detection efficiency by changing the number of Sci-Fi, and discrimination property against 2.4 MeV neutrons produced through DD reactions and gamma rays. However, its length had conventionally been set to around 10 cm without an optimization study of its design parameters to meet the requirements as 14 MeV neutron detector. In the present study, we tested three types of Sci-Fi detectors with three different lengths and compared with the simulated results of energy deposition, through which we tried to understand the phenomena in the detection process of fast neutrons. From the results, it has been shown that, due to the self-shielding of neutrons by Sci-Fi and the attenuation of scintillation photons during the transmission process to the photomultiplier tube, the optimal length of Sci-Fi is concluded to be about 6 cm.
Magnetic field stabilization system for atomic physics experiments
Authors: Merkel B. , Thirumalai K. , Tarlton J. E. , Schäfer V. M. , Ballance C. J. , Harty T. P. , Lucas D. M.
Published: April 2019

Atomic physics experiments commonly use millitesla-scale magnetic fields to provide a quantization axis. As atomic transition frequencies depend on the magnitude of this field, many experiments require a stable absolute field. Most setups use electromagnets, which require a power supply stability not usually met by commercially available units. We demonstrate the stabilization of a field of 14.6 mT to 4.3 nT rms noise (0.29 ppm), compared to noise of >100 nT without any stabilization. The rms noise is measured using a field-dependent hyperfine transition in a single 43Ca+ ion held in a Paul trap at the center of the magnetic field coils. For the 43Ca+ “atomic clock” qubit transition at 14.6 mT, which depends on the field only in second order, this would yield a projected coherence time of many hours. Our system consists of a feedback loop and a feedforward circuit that control the current through the field coils and could easily be adapted to other field amplitudes, making it suitable for other applications such as neutral atom traps.
Active diffusion limited reactions
Authors: Debnath Tanwi , Ghosh Pulak K. , Li Yunyun , Marchesoni Fabio , Nori Franco
Published: April 2019

We investigate the one- and two-dimensional diffusion limited reactions A + A → 0 and A + B → 0 with A active Janus particles and B passive particles in thermal equilibrium. We show that by increasing the self-propulsion time of the A particles, the reactant densities decay faster, at least for time transients of potential interest for chemical applications, e.g., to develop smart drug delivery protocols. Asymptotic and transient density decays obey power laws with exponents that depend on the actual annihilation reaction and its dimensionality.
Effects of shear intensity and aspect ratio on three-dimensional wake characteristics of flow past surface mounted circular cylinder
Authors: Kumar Prashant , P. Manelil Neeraj , Tiwari Shaligram
Published: April 2019

Three-dimensional numerical computations have been carried out for flow past a surface mounted finite height circular cylinder using Open Source Field Operation and Manipulation. Flow field characteristics have been investigated for fixed Reynolds number equal to 300 and varying aspect ratios (AR being the ratio of height to diameter of the cylinder) from 1 to 5. The effect of nonuniform flow (linear shear) with shear intensity (K) ranging from 0 to 0.3 on flow field characteristics has been examined using iso-Q surfaces and streamline plots. Three different flow regimes are reported based on the values of AR and K: steady flow, symmetric mode, and antisymmetric mode of vortex shedding. The formation of critical points (impingement point, source, and spiral node) has been explained using the time-averaged flow field in the longitudinal plane of symmetry. Surface flow topology has been presented with the help of limiting streamlines on the surface of the cylinder. Variation in mean drag coefficient with a change in K has also been reported. Unsteady periodic and aperiodic wake flows have been characterized using the Hilbert spectra of the transverse velocity signal at a point in the wake. The extent of nonlinear interaction in the wake and its influence on frequency distribution have been analyzed using marginal spectra and quantified in terms of degree of stationarity.
Ultraviolet light induced electrical hysteresis effect in graphene-GaN heterojunction
Authors: Ranade Ajinkya K. , Mahyavanshi Rakesh D. , Desai Pradeep , Kato Masashi , Tanemura Masaki , Kalita Golap
Published: April 2019

Fabrication of a two- and three-dimensional (2D/3D) heterojunction device has attracted significant attention for developing high performance photodiodes, light emitting diodes, solar cells, and other electronic devices. Here, we reveal the effect of ultraviolet (UV) illumination on electrical hysteresis in a graphene/gallium nitride (GaN) vertical heterojunction Schottky device. A chemical vapor deposited graphene film was transferred onto a free-standing n-type GaN substrate for Schottky diode fabrication, where the interfacial states play a significant role in the occurrence of electrical hysteresis in diode characteristics. A fabricated graphene/GaN Schottky device free from electrical hysteresis under no illumination condition showed the appearance of hysteresis with the illumination of UV light. The residual impurities of graphene and the surface defects of the GaN act as trap sites for the photocarriers; as a result, interface dependent photoresponsivity was observed. Capacitance-voltage analysis also showed the effect of residual impurities on the space charge dependent capacitance and the occurrence of hysteresis due to interface traps of the graphene/GaN heterojunction. Our findings can be significant in understanding the highly sensitive graphene/GaN and other 2D/3D heterojunction interfaces by the UV illumination process for developing high performance devices.
Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions
Authors: Du X. D. , Shafer M. W. , Hu Q. M. , Evans T. E. , Strait E. J. , Ohdachi S. , Suzuki Y.
Published: April 2019

The evolution of the magnetic topology between the outer separatrix of a large m = 2/n = 1 island (m and n: poloidal and toroidal numbers) and the last closed flux surface after mode locking is, for the first time, directly measured. Edge locked island chains with multiple helicity and very narrow widths are discovered to be destabilized and govern the cooling process in the plasma peripheral region. These edge small nonrotating islands are initially well separated from the 2/1 island, leading to a long quasistationary phase, but later trigger thermal quench immediately after they start to overlap with the 2/1 island, producing a broad stochastic layer deep into the plasma midradius.
Broadband lumped-element Josephson parametric amplifier with single-step lithography
Authors: Elo T. , Abhilash T. S. , Perelshtein M. R. , Lilja I. , Korostylev E. V. , Hakonen P. J.
Published: April 2019

We present a lumped-element Josephson parametric amplifier (JPA) fabricated using a straightforward e-beam lithography process. Our strongly coupled flux-pumped JPA achieves a gain of 20 dB with a bandwidth of 95 MHz around 5 GHz, while the center frequency is tunable by more than 1 GHz, with the additional possibility for rapid tuning by varying the pump frequency alone. Analytical calculations based on the input-output theory reproduce our measurement results closely.
ZMP-SAPT: DFT-SAPT using ab initio densities
Authors: Boese A. Daniel , Jansen Georg
Published: April 2019

Symmetry Adapted Perturbation Theory (SAPT) has become an important tool when predicting and analyzing intermolecular interactions. Unfortunately, Density Functional Theory (DFT)-SAPT, which uses DFT for the underlying monomers, has some arbitrariness concerning the exchange-correlation potential and the exchange-correlation kernel involved. By using ab initio Brueckner Doubles densities and constructing Kohn-Sham orbitals via the Zhao-Morrison-Parr (ZMP) method, we are able to lift the dependence of DFT-SAPT on DFT exchange-correlation potential models in first order. This way, we can compute the monomers at the coupled-cluster level of theory and utilize SAPT for the intermolecular interaction energy. The resulting ZMP-SAPT approach is tested for small dimer systems involving rare gas atoms, cations, and anions and shown to compare well with the Tang-Toennies model and coupled cluster results.
Constructing multi-butterfly attractors based on Sprott C system via non-autonomous approaches
Authors: Wu Qiujie , Hong Qinghui , Liu Xiaoyang , Wang Xiaoping , Zeng Zhigang
Published: April 2019

In this paper, two different pulse control methods are proposed to generate multi-butterfly attractors based on the Sprott C system. By introducing a bipolar multilevel pulse signal to the boostable variable z of the Sprott C system, translational multi-butterfly attractors with constant Lyapunov exponents can be obtained. Another method for generating nested multi-butterfly attractors is to replace the DC voltage of the Sprott C system with the unipolar multilevel pulse signal, and the dynamical behavior involves the superposition of multiple attractors corresponding to different pulse amplitudes. By defining time as an additional state variable, the proposed non-autonomous systems can be transformed into autonomous systems for analysis. It can be seen that systems have no equilibria, so they belong to hidden attractors. A normalized circuit implementation is given, translational and nested hidden multi-butterfly attractors can be obtained by setting proper pulse signals. Moreover, the number of butterflies can be adjusted by changing the number of pulse voltage sources without reconstructing nonlinear functions. Theoretical analysis and simulation results prove the effectiveness of these methods.
Comparison of active and passive methods for the infrared scanning near-field microscopy
Authors: Weng Qianchun , Panchal Vishal , Lin Kuan-Ting , Sun Liaoxin , Kajihara Yusuke , Tzalenchuk Alexander , Komiyama Susumu
Published: April 2019

We systematically compare the active and the passive methods for infrared scattering-type scanning near-field optical microscopy (s-SNOM). The active SNOM makes use of IR lasers or incoherent thermal emitters to illuminate a sample, whereas the passive method directly measures extremely weak fluctuating electromagnetic evanescent fields spontaneously generated at the sample surface without any external illumination. For this reason, our specific version of the passive SNOM is called a scanning noise microscope (SNoiM). In thermal equilibrium, the two methods are shown to be similar, both mapping the nanoscale variation of the complex dielectric constant of the sample. We demonstrate that a significant difference between the two methods emerges when the sample is driven out of thermal equilibrium, viz., the active SNOM is insensitive whereas the SNoiM is extremely sensitive to the electron temperature in locally heated nanoregions.
Saturated fluorescence spectroscopy measurement apparatus based on metastable Li+ beam with low energy
Authors: Chen Shaolong , Liang Shiyong , Sun Wei , Huang Yao , Guan Hua , Gao Kelin
Published: April 2019

The apparatus for fluorescence spectroscopy measurement is developed to determine the fine structure (FS)/hyperfine structure (HFS) splittings of 1s2p 3PJ(J=0,1,2) states of Li+. The instrument is composed of a low energy Li+ ion source and a saturated fluorescence spectroscopic probing system. A low energy Li+ ion source, containing 1.8(7)% of 1s2s 3S1 metastable ions with an energy of ∼500 eV, is obtained by an electron bombardment process. The ion current can stay more than 250 h with the variation of ∼0.3%, and the divergence of ion beam is ∼0.5 mrad. The symmetric profile of Lamb dip signals of 1s2s 3S1−−1s2p 3PJ transitions with linewidths of ∼50 MHz are obtained after subtracting Doppler background from the saturated fluorescence signals. A back-and-forth scan method is adopted to determine the FS/HFS splittings of 1s2p 3PJ states. Under these conditions, as a preliminary test, several splittings of 7Li+ are measured. The statistical uncertainties of the FS/HFS splittings are estimated to be less than 50 kHz, and the results are one order of magnitude better than previous results. The apparatus is feasible to precisely determine the splittings of energy levels of alkali and alkaline earth ions.
Electrical impedance-based characterization of electrostatic suppression of the Leidenfrost state
Authors: Ozkan Onur , Bahadur Vaibhav
Published: April 2019

A drop of liquid will levitate on its own vapor on a sufficiently hot surface (the Leidenfrost effect). Application of an electric field across the vapor gap suppresses the Leidenfrost state by electrostatically attracting liquid towards the surface. This study highlights and quantifies the statistical nature of wetting during electrostatic suppression via electrical impedance characterization of Leidenfrost pools under electrostatic suppression. The influence of the electric field, surface superheat, and size of the Leidenfrost pool on the wetted area is studied. High-speed measurements (0.01 s resolution) indicate that the wetted area is not constant during electrostatic suppression, but instead fluctuates. This technique can also be used to study the onset of suppression. Interestingly, we identify two distinct threshold voltages required to initiate periodic and continuous electrostatic suppression, respectively. The dependence of these voltages on surface superheat and the frequency of the applied AC waveform is studied. Together, these results enable an in-depth understanding of electrostatic suppression and highlight the benefits of impedance-based characterization towards understanding the Leidenfrost effect.
Microwave-magnetic-field-induced magnetization excitation and assisted switching of antiferromagnetically coupled magnetic bilayer with perpendicular magnetization
Authors: Suto Hirofumi , Kanao Taro , Nagasawa Tazumi , Mizushima Koichi , Sato Rie , Kikuchi Nobuaki , Okamoto Satoshi
Published: April 2019

Antiferromagnetically coupled (AFC) magnetic bilayer is a candidate media structure for high-density magnetic recording. Because the stray fields from the two magnetic layers of the AFC bilayer cancel each other out, switching field distribution originating from the stray fields from the adjacent data bits can be suppressed. Furthermore, in microwave-assisted magnetic recording (MAMR), which utilizes ferromagnetic resonance (FMR) excitation in a microwave field to reverse a high-anisotropy magnetic material, AFC media can suppress the distribution in FMR frequency originating from the stray fields and improve MAMR performance. In this study, we fabricate an AFC magnetic bilayer consisting of two Co/Pt multilayers with perpendicular magnetization. We use anomalous-Hall-effect-FMR in combination with a circularly polarized microwave field and carry out layer-selective analysis of FMR excitation of the two magnetic layers. We then investigate the switching behavior of an AFC bilayer nanodot in a microwave magnetic field. The switching field decreases with increasing microwave field frequency and increases abruptly at the critical frequency, and a large switching field reduction by applying a microwave field is demonstrated. This switching behavior is similar to that of a single-layer perpendicular magnetic nanodot, showing that the AFC structure does not hinder the microwave assist effect.
Surface configurations and wave patterns of thermocapillary convection onboard the SJ10 satellite
Authors: Kang Qi , Wu Di , Duan Li , He Jianwu , Hu Liang , Duan Longsheng , Hu Wenrui
Published: April 2019

A fluid experiment was conducted on China’s SJ10 satellite to assess the instability of thermocapillary convection under microgravity. Oscillations of thermocapillary convection in an annular pool were investigated when the difference in temperature exceeded a certain threshold. Dynamics and transitions of the wave pattern were observed using an infrared camera. This work is concerned with the effect of the surface configuration on the wave patterns. There are 3 types of surface configurations that depend on the volume ratio: Vr < 0.77 (zone 1), 0.77 < Vr < 1 (zone 2), and Vr > 1 (zone 3). An irregular local wave occurs at Vr < 0.65, and a regular azimuthal wave occurs at Vr > 0.65. We observed the regular wave with the wavenumber m = 3 in zone 1 and zone 3 and the competition between m = 3 and m = 4 in zone 2. The nonlinear dynamics of traveling waves, standing waves, and counterpropagating waves were studied. The standing wave appears near the onset and transitions to the traveling wave. With a similar mechanism, counterpropagating waves with m = 3 and m = 4 occur in some cases at the onset. Additionally, counterpropagating waves also act as a transitional mode when the traveling wave transitions from m = 4 to m = 3. The traveling wave is very stable, but it develops into standing waves or Benjamin-Feir instability under highly supercritical conditions.
H2, HD, and D2 in the small cage of structure II clathrate hydrate: Vibrational frequency shifts from fully coupled quantum six-dimensional calculations of the vibration-translation-rotation eigenstates
Authors: Lauvergnat David , Felker Peter , Scribano Yohann , Benoit David M. , Bačić Zlatko
Published: April 2019

We report the first fully coupled quantum six-dimensional (6D) bound-state calculations of the vibration-translation-rotation eigenstates of a flexible H2, HD, and D2 molecule confined inside the small cage of the structure II clathrate hydrate embedded in larger hydrate domains with up to 76 H2O molecules, treated as rigid. Our calculations use a pairwise-additive 6D intermolecular potential energy surface for H2 in the hydrate domain, based on an ab initio 6D H2–H2O pair potential for flexible H2 and rigid H2O. They extend to the first excited (v = 1) vibrational state of H2, along with two isotopologues, providing a direct computation of vibrational frequency shifts. We show that obtaining a converged v = 1 vibrational state of the caged molecule does not require converging the very large number of intermolecular translation-rotation states belonging to the v = 0 manifold up to the energy of the intramolecular stretch fundamental (≈4100 cm−1 for H2). Only a relatively modest-size basis for the intermolecular degrees of freedom is needed to accurately describe the vibrational averaging over the delocalized wave function of the quantum ground state of the system. For the caged H2, our computed fundamental translational excitations, rotational j = 0 → 1 transitions, and frequency shifts of the stretch fundamental are in excellent agreement with recent quantum 5D (rigid H2) results [A. Powers et al., J. Chem. Phys. 148, 144304 (2018)]. Our computed frequency shift of −43 cm−1 for H2 is only 14% away from the experimental value at 20 K.
Electrostatic contribution to hysteresis loop in piezoresponse force microscopy
Authors: Qiao Huimin , Seol Daehee , Sun Changhyo , Kim Yunseok
Published: April 2019

In piezoresponse force microscopy (PFM), ideally, electromechanical strain is induced only by the converse piezoelectric effect. In reality, however, the obtained experimental PFM signal is a combination of many other factors. In particular, the concurrent electrostatic effect between the tip/cantilever and a sample surface can be significant because the electrostatic effect induced by surface potential is inevitable in some cases. However, most previous reports dealt with the extreme case of the electrostatic effect, such as the on-field state. That is, the contributions to the hysteresis loop of electrostatic effects from different sources have not yet been clearly understood. In the present work, we study the electrostatic effect on the hysteresis loop in relation to various measurement parameters. The results indicate that the PFM response is strongly affected by the electrostatic effect caused by external charge injection. This work can provide a guideline for determining the PFM response in a hysteresis loop.
Pressure field generated in porous medium by air jet injected through the surface
Authors: Yarin A. L. , Schuster K. , Zussman E.
Published: April 2019

Efficient detection of hidden volatile substances in soil requires understanding the mechanisms governing their retention or transport through porous medium. In order to increase the mass transfer rate of the hidden volatile substances, it was suggested in this work to apply forced-convection (filtration) in addition to diffusion by using a gas jet impingement vertically onto the soil (a granular bed; sand). Pressure distribution in the granular bed is studied analytically using the methods from the theory of functions of complex variables. The filtration/granular bed interaction involves the soil permeability, grain size, and jet pressure and impinging velocity. Soil failure due to the filtration-imposed forces is formulated as the Mohr-Coulomb criterion, which involves the angle of internal friction and the cohesion of grains. A comprehensive experimental investigation of the filtration pressure distribution and the jet-driven erosion of granular material is presented here. The experiments were conducted by combining a special pressure-measurement technique allowing for a simultaneous accurate detection of the crater onset and the subsequent evolution of the granular bed. The theoretical predictions are compared to the measured pressure field in the granular bed.
Anomalously high electronic thermal conductivity and Lorenz ratio in Bi2Te3 nanoribbons far from the bipolar condition
Authors: Choe Hwan Sung , Li Jiachen , Zheng Wenjing , Lee Jaejun , Suh Joonki , Allen Frances I. , Liu Huili , Choi Heon-Jin , Walukiewicz Wladek , Zheng Haimei , Wu Junqiao
Published: April 2019

The Lorenz number (L) of a conductor is the ratio between its electronic thermal conductivity and electrical conductivity. It takes the Sommerfeld value of L0=π2/3kB/e2 in simple, metallically electronic systems where charge and heat are both carried by the same group of quasi-particles that experience elastic scattering. Higher values of L than L0 are possible in semiconductors where both electrons and holes co-exist at high densities, that is, in bipolar conduction. As a narrow-bandgap semiconductor, Bi2Te3 exhibits L > L0 which has been generally attributed to such bipolar conduction mechanisms. However, in this work, we report that L > L0 is still observed in individual, single-crystal Bi2Te3 nanoribbons even at low temperatures and when degenerately doped, that is, far from the bipolar conduction condition. This discovery calls for different mechanisms to explain the unconventional electronic thermal transport behavior in Bi2Te3.
A combined experimental and theoretical investigation of Cs+ ions solvated in HeN clusters
Authors: Pérez de Tudela Ricardo , Martini Paul , Goulart Marcelo , Scheier Paul , Pirani Fernando , Hernández-Rojas Javier , Bretón José , Ortiz de Zárate Josu , Bartolomei Massimiliano , González-Lezana Tomás , Hernández Marta I. , Campos-Martínez José , Villarreal Pablo
Published: April 2019

Solvation of Cs+ ions inside helium droplets has been investigated both experimentally and theoretically. On the one hand, mass spectra of doped helium clusters ionized with a crossed electron beam, HeNCs+, have been recorded for sizes up to N = 60. The analysis of the ratio between the observed peaks for each size N reveals evidences of the closure of the first solvation shell when 17 He atoms surround the alkali ion. On the other hand, we have obtained energies and geometrical structures of the title clusters by means of basin-hopping, diffusion Monte Carlo (DMC), and path integral Monte Carlo (PIMC) methods. The analytical He–Cs+ interaction potential employed in our calculations is represented by the improved Lennard-Jones expression optimized on high level ab initio energies. The weakness of the existing interaction between helium and Cs+ in comparison with some other alkali ions such as Li+ is found to play a crucial role. Our theoretical findings confirm that the first solvation layer is completed at N = 17 and both evaporation and second difference energies obtained with the PIMC calculation seem to reproduce a feature observed at N = 12 for the experimental ion abundance. The analysis of the DMC probability distributions reveals the important contribution from the icosahedral structure to the overall configuration for He12Cs+.
Parameter regulation of underwater shock waves based on exploding-wire-ignited energetic materials
Authors: Han Ruoyu , Wu Jiawei , Zhou Haibin , Zhang Yongmin , Qiu Aici
Published: April 2019

This paper proposed and verified a method for adjusting parameters of underwater shock waves. In the experiments, a metal wire with an energetic material coat was exploded by applying a pulsed current on it. Under different matches of size/material of wire, mass/type of energetic material, and injected pulsed current, characteristics of shock waves were obtained. It has been proven that peak pressure, impulse, and energy of shock waves can be conveniently regulated by simply changing the explosion of either the wire or its energetic material coat. Finally, the mechanisms of this method were analyzed and potential applications discussed.
Tunable electronic properties of van der Waals heterostructures composed of stanene adsorbed on two-dimensional, graphene-like nitrides
Authors: Yelgel Celal
Published: April 2019

We investigated the structural stability and electronic properties of stanene/graphene-like nitride (stanene/XN, X=Al, B, and Ga) heterostructures using first-principles calculations. The results reveal that stanene interacts with BN (GaN) via van der Waals interactions with a binding energy of 93 meV (171 meV) per Sn atom. In contrast, the stanene/AlN heterostructure shows a strong interlayer coupling, with a binding energy of 315 meV per Sn atom. The electronic structure of stanene/GaN shows a direct bandgap of 213 meV at the Dirac point. The stanene/AlN and stanene/GaN heterostructures have Schottky barriers of 1.383 and 1.243 eV, respectively, with p-type Schottky contacts. In addition, an n-type Schottky contact is formed in the stanene/BN heterostructure with a Schottky barrier of 2.812 eV. The results suggest that the studied heterostructures are potential candidates for stanene-based nanoelectronic applications.
Effects of ocean acidification and short-term light/temperature stress on biogenic dimethylated sulfur compounds cycling in the Changjiang River Estuary
Authors: Jian Shan , Zhang Jing , Zhang Hong-Hai , Yang Gui-Peng
Published: April 2019

Environmental contextContinuous anthropogenic CO2 emissions have led to an increase in seawater acidity, potentially affecting the growth of phytoplankton and their production of the climate-moderating biogenic gas, dimethyl sulfide. Our simulation experiments showed that ocean acidification, coupled with light and temperature changes, had a significant influence on dimethyl sulfide concentrations. This research provides fundamental data for predicting the biogeochemical cycle of dimethyl sulfide under various global change scenarios. AbstractOcean acidification (OA) affects marine primary productivity and community structure. Therefore, OA may influence the biogeochemical cycles of volatile biogenic dimethyl sulfide (DMS), and its precursor dimethylsulfoniopropionate (DMSP) and photochemical oxidation product dimethyl sulfoxide (DMSO). A 23-day shipboard incubation experiment investigated the short-term response of the production and cycling of biogenic sulfur compounds to OA in the Changjiang River Estuary to understand the effects of OA on biogenic sulfur compounds. Phytoplankton abundance and community composition showed a marked difference at three different pH levels at the late stage of the experiment. Significant reductions in chlorophyll a (Chl-a), DMS, particulate DMSP (DMSPp) and dissolved DMSO (DMSOd) concentrations were identified under high CO2 levels. Moreover, minimal changes were observed in the productions of dissolved DMSP (DMSPd) and particulate DMSO (DMSOp) among the treatments. The ratios of DMS, total DMSP (DMSPt) and total DMSO (DMSOt) to Chl-a were not affected by a change in pH. Furthermore, the concentrations of DMS and DMSOd were closely related to the mean bacterial abundance at the three pH levels. Additional short-term (8h) incubation experiments on the light and temperature effects showed that the influence of pH on the production of dimethylated sulfur compounds also depended on solar radiation and temperature. Under natural and UVB light, DMS photodegradation rates increased by 1.6 to 4.2 times at low pH levels. Thus, OA may lead to decreasing DMS concentrations in surface seawater. Light and temperature conditions also play important roles in the production and cycling of biogenic sulfur compounds.
Hydrology and water temperature influence recruitment dynamics of the threatened silver perch Bidyanus bidyanus in a regulated lowland river
Authors: Tonkin Zeb , Stuart Ivor , Kitchingman Adrian , Thiem Jason D. , Zampatti Brenton , Hackett Graeme , Koster Wayne , Koehn John , Morrongiello John , Mallen-Cooper Martin , Lyon Jarod
Published: April 2019

Understanding the influence of extrinsic factors such as hydrology and hydraulics on recruitment provides essential insight to inform management of fish populations. The critically endangered silver perch Bidyanus bidyanus is a long-lived, potamodromous pelagophil endemic to Australia’s Murray–Darling Basin. Declines of this species are often attributed to river regulation, although quantitative studies linking hydrology and hydraulics to key aspects of its life cycle are sparse. We used a multidecadal age-structured dataset collected from a locally abundant population of silver perch to quantify the relative importance of different abiotic drivers on year-class strength (recruitment). Silver perch recruited across highly variable hydrological conditions. The strongest year classes were associated with a combination of low to average river discharge (i.e. within channel) and high water temperatures over the peak spawning period, followed in the next year by extended high flows and widespread flooding that promoted survival of age-1+ juvenile fish. We suggest that conditions affecting the growth and dispersal of juvenile fish, in addition to the spawning period, are critical in governing recruitment dynamics. This highlights the need for multiyear flow plans for freshwater fish populations.
Rap1 binding and a lipid-dependent helix in talin F1 domain promote integrin activation in tandem
Authors: Gingras Alexandre R. , Lagarrigue Frederic , Cuevas Monica N. , Valadez Andrew J. , Zorovich Marcus , McLaughlin Wilma , Lopez-Ramirez Miguel Alejandro , Seban Nicolas , Ley Klaus , Kiosses William B. , Ginsberg Mark H.
Published: April 2019

Rap1 GTPases bind effectors, such as RIAM, to enable talin1 to induce integrin activation. In addition, Rap1 binds directly to the talin1 F0 domain (F0); however, this interaction makes a limited contribution to integrin activation in CHO cells or platelets. Here, we show that talin1 F1 domain (F1) contains a previously undetected Rap1-binding site of similar affinity to that in F0. A structure-guided point mutant (R118E) in F1, which blocks Rap1 binding, abolishes the capacity of Rap1 to potentiate talin1-induced integrin activation. The capacity of F1 to mediate Rap1-dependent integrin activation depends on a unique loop in F1 that has a propensity to form a helix upon binding to membrane lipids. Basic membrane-facing residues of this helix are critical, as charge-reversal mutations led to dramatic suppression of talin1-dependent activation. Thus, a novel Rap1-binding site and a transient lipid-dependent helix in F1 work in tandem to enable a direct Rap1–talin1 interaction to cause integrin activation.
T cell anergy in perinatal mice is promoted by T reg cells and prevented by IL-33
Authors: Tuncel Jonatan , Benoist Christophe , Mathis Diane
Published: April 2019

Perinatal T cells broadly access nonlymphoid tissues, where they are exposed to sessile tissue antigens. To probe the outcome of such encounters, we examined the defective elimination of self-reactive clones in Aire-deficient mice. Nonlymphoid tissues were sequentially seeded by distinct waves of CD4+ T cells. Early arrivers were mostly Foxp3+ regulatory T (T reg) cells and metabolically active, highly proliferative conventional T cells (T conv cells). T conv cells had unusually high expression of PD-1 and the IL-33 receptor ST2. As T conv cells accumulated in the tissue, they gradually lost expression of ST2, ceased to proliferate, and acquired an anergic phenotype. The transition from effector to anergic state was substantially faster in ST2-deficient perinates, whereas it was abrogated in IL-33–treated mice. A similar dampening of anergy occurred after depletion of perinatal T reg cells. Attenuation of anergy through PD-1 blockade or IL-33 administration promoted the immediate breakdown of tolerance and onset of multiorgan autoimmunity. Hence, regulating IL-33 availability may be critical in maintaining T cell anergy.
Position-controlled laser-induced creation of rutile TiO2 nanostructures
Authors: Kalb Julian , Weller Fabian , Irmler Lukas , Knittel Vanessa , Graus Philipp , Boneberg Johannes , Schmidt-Mende Lukas
Published: April 2019

For potential applications of nanostructures, control over their position is important. In this report, we introduce two continuous wave laser-based lithography techniques which allow texturing thin TiO2 films to create a fine rutile TiO2 structure on silicon via spatially confined oxidation or a solid–liquid–solid phase transition, for initial layers, we use titanium and anatase TiO2, respectively. A frequency-doubled Nd:YAG laser at a wavelength of 532 nm is employed for the lithography process and the samples are characterized with scanning electron microscopy. The local orientation of the created rutile crystals is determined by the spatial orientation of hydrothermally grown rutile TiO2 nanorods. Depending on the technique, we obtain either randomly aligned or highly ordered nanorod ensembles. An additional chemically inert SiO2 cover layer suppresses the chemical and electronic surface properties of TiO2 and is removed locally with the laser treatment. Hence, the resulting texture provides a specific topography and crystal structure as well as a high contrast of surface properties on a nanoscale, including the position-controlled growth of TiO2 nanorods.
Predicting support for flood mitigation based on flood insurance purchase behavior
Authors: Shao Wanyun , Feng Kairui , Lin Ning
Published: April 2019

What is the decision-making mechanism people rely upon to mitigate flood risk? Applying Bayesian Network modeling to a comprehensive survey dataset for the US Gulf Coast, we find that the overall support for flood mitigation can be inferred from flood insurance purchase behavior (i.e. without insurance versus with insurance purchased mandatorily, voluntarily, or both). Therefore, we propose a theoretical decision-making mechanism composed of two dimensions including informed flood risk and sense of insecurity. The informed flood risk is the primary determinant on one’s overall support for flood mitigation. Risk mitigation decisions are largely contingent on the level of risk that is effectively conveyed to individuals. Additionally, sense of insecurity plays a moderate role in determining individuals’ overall support for flood mitigation. The sense of insecurity can move people toward overall support for mitigation, but the effect is not as large as the informed risk. Results of this study have fundamental policy implications. The flood risk informed by Federal Emergency Management Agency’s flood maps not only provides the compulsory basis for flood insurance purchase but also determines individuals’ overall support for flood mitigation. Flood map inaccuracy can immensely mislead individuals’ overall risk mitigation decision. Meanwhile, this flood risk mitigation decision-making mechanism inferred from a survey data in the US Gulf Coast needs to be tested and validated elsewhere.
The drivers of nonlinear local temperature change under global warming
Authors: King Andrew D
Published: April 2019

How the pattern of the Earth’s surface warming will change under global warming represents a fundamental question for our understanding of the climate system with implications for regional projections. Despite the importance of this problem there have been few analyses of nonlinear local temperature change as a function of global warming. Individual climate models project nonlinearities, but drivers of nonlinear local change are poorly understood. Here, I present a framework for the identification and quantification of local nonlinearities using a time-slice analysis of a multi-model ensemble. Accelerated local warming is more likely over land than ocean per unit global warming. By examining changes across the model ensemble, I show that models that exhibit summertime drying over mid-latitude land regions, such as in central Europe, tend to also project locally accelerated warming relative to global warming, and vice versa. A case study illustrating some uses of this framework for nonlinearity identification and analysis is presented for north-eastern Australia. In this region, model nonlinear warming in summertime is strongly connected to changes in precipitation, incoming shortwave radiation, and evaporative fraction. In north-eastern Australia, model nonlinearity is also connected to projections for El Niño. Uncertainty in nonlinear local warming patterns contributes to the spread in regional climate projections, so attempts to constrain projections are explored. This study provides a framework for the identification of local temperature nonlinearities as a function of global warming and analysis of associated drivers under prescribed global warming levels.
CFTR mutation compromises spermatogenesis by enhancing miR-15b maturation and suppressing its regulatory target CDC25A†
Authors: Chen Yan , Li Xiaoliang , Liao Huijuan , Leung Xiaotong , He Jiabei , Wang Xiang , Li Fuping , Yue Huanxun , Xu Wenming
Published: April 2019

MicroRNAs (miRNAs) have recently been shown to be important for spermatogenesis; both DROSHA and Dicer1 KO mice exhibit infertility due to abnormal miRNA expression. However, the roles of individual miRNAs in spermatogenesis remain elusive. Here we demonstrated that miR-15b, a member of the miR-15/16 family, is primarily expressed in testis. A miR-15b transgenic mouse model was constructed to investigate the role of miR-15b in spermatogenesis. Impaired spermatogenesis was observed in miR-15b transgenic mice, suggesting that appropriate expression of miR-15b is vital for spermatogenesis. Furthermore, we demonstrated that overexpression of miR-15b reduced CDC25A gene post-transcriptional activity by targeting the 3′-UTR region of CDC25A, thus regulating spermatogenesis. In vitro results further demonstrated that a mutation in CFTR could affect the interaction between Ago2 with Dicer1 and that Dicer1 activity regulates miR-15b expression. We extended our study to azoospermia patients and found that infertile patients have a significantly higher level of miR-15b in semen and plasma samples. Taken together, we propose that CFTR regulation of miR-15b could be involved in the post-transcriptional regulation of CDC25A in mammalian testis and that miR-15b is important for spermatogenesis.
Impaired decidualization caused by downregulation of circadian clock gene BMAL1 contributes to human recurrent miscarriage†
Authors: Lv Shijian , Wang Na , Ma Jin , Li Wei-Ping , Chen Zi-Jiang , Zhang Cong
Published: April 2019

Recurrent miscarriage (RM) is characterized by two or more consecutive losses of a clinically established intrauterine pregnancy at early gestation. To date, the etiology of RM remains poorly understood. Impaired decidualization is thought to predispose women to subsequent pregnancy failure. The transcriptional factor brain and muscle aryl hydrocarbon receptor nuclear translocator-like (BMAL1) controls circadian rhythms and regulates a very large diversity of physiological processes. BMAL1 is essential for fertility. Here, we investigated the expression and function of BMAL1 in human decidualization and its relation with RM. A total of 39 decidua samples were collected. We also examined human endometrial stromal cells (HESCs) and primary endometrial stromal cells (ESCs), and primary decidual stromal cells (DSCs) isolated from decidua of first-trimester pregnancies. Compared to normal pregnant women, the expression of BMAL1 was reduced in the decidual tissues from individuals with RM. After in vitro induction of decidualization, the transcription of BMAL1 in both HESCs and primary ESCs was increased. This is in line with the relatively higher expression of BMAL1 in DSCs than in ESCs. Silencing of BMAL1 resulted in impaired decidualization. Moreover, levels of tissue inhibitors of metalloproteinases (TIMPs) increased significantly upon decidualization. Further experiments demonstrated that BMAL1 silencing curtails the ability of DSCs to restrict excessive trophoblast invasion via downregulation of TIMP3. Our study demonstrates a functional role for BMAL1 during decidualization: the downregulation of BMAL1 in RM leads to impaired decidualization and aberrant trophoblast invasion by regulating TIMP3 and consequently predisposing individuals for RM.