bluuebunny/crossref_metadata_2025 huggingface dataset:
TDCC: top‐down semantic aggregation for colour constancy
Authors: Li Xiaoqiang , Zhu Yaqin , Han Jiayue , Li Jide , Lian Huicheng , Tong Weiqin
Published: July 2019

Images obtained from an illuminated scene often have their original colour contaminated. Colour constancy is a study considering how to restore them. Substantial progress on colour constancy has been made in recent years due to the development of a convolutional neural network (CNN). In a CNN structure, high‐level features contain semantic information while low‐level features show local details. If both are taken into account, they would help achieve a more accurate illuminant estimation. However, previous works paid little attention to the latter for lack of frameworks, which can combine those two kinds of features together. Inspired by the pyramid model, a top‐down network that successively propagates high‐level information to low‐level layers is proposed. This network, named top‐down semantic aggregation for colour constancy (TDCC), takes full advantage of the multi‐scale representations with strong semantics. As a result, objects with intrinsic colours are captured and a better estimation is obtained. Experiments on three benchmark datasets demonstrate that TDCC significantly outperforms state‐of‐the‐art colour constancy methods.
Optimal operating control strategy for biogas generation under electricity spot market
Authors: Cao Yijia , Wei Juan , Li Canbing , Zhou Bin , Huang Longjie , Feng Guang , Yang Hanyu
Published: July 2019

This study presents an approach of biogas generation coupled with electricity trading under electricity spot market to maximise the biogas power profits. The aim of this study is to achieve a minimal generation cost for the biogas generation system while eliminating the dependence on batteries due to the storage and tunable properties of biogas digester. In terms of the electricity prices at different times in the spot market, the operating control strategy for biogas generation is established to perform the optimal generation scheduling, which give the two model comparison results. The practical case of biogas engineering in the ecological park in Hunan Province in China is carried out to validate the effectiveness and practicability of the proposed strategy.
Complementarity assessment of wind‐solar energy sources in Shandong province based on NASA
Authors: Cao Yongji , Zhang Yi , Zhang Hengxu , Zhang Pengfei
Published: July 2019

The inherent complementarity of wind and solar energy resources is beneficial to smooth aggregate power and reduce ramp reserve capacity. This article proposes a progressive approach to assess the wind‐solar complementarities in Shandong province, China for the preliminary planning of hybrid energy systems. Based on the NASA database, the long‐term wind speed and solar irradiation data are obtained and transformed into capacity factors by virtual energy system models. Then, the local assessment that focuses on temporal characteristics is carried out to measure the complementarities in different time scales and search the optimal scale. Progressively, the space scale is extended from a local site to the whole study region and the global assessment is conducted to extract the spatial complementary characteristics. The assessment results are useful to provide the optimal temporal scale and spatial combination of wind‐solar complementarity and the proposed approach can be generalised to other regions.
Solar energy production forecasting through artificial neuronal networks, considering the Föhn, north and south winds in San Juan, Argentina
Authors: Parra Raffán Luis Carlos , Romero Andrés , Martinez Maximiliano
Published: July 2019

This study presents a method to predict a day‐ahead solar irradiation curve, under extreme meteorological phenomena (Föhn, north and south winds), existing in the province of San Juan, Argentina. The proposed method is based on an artificial neuronal network (ANN) which is trained with a data set filtered by the environmental variables that characterise the mentioned phenomena. A previously calculated ideal solar irradiation curve is modified from the forecasts generated by the ANN. The proposed methodology merges statistical learning methods and numerical weather prediction (NWP) methods, typically used to improve upon the raw forecast of a NWP model. A reduction of the uncertainty in the power production of photovoltaic plants in San Juan can be achieved with the results of the proposed forecasting method.
DeepActivity: a micro‐Doppler spectrogram‐based net for human behaviour recognition in bio‐radar
Authors: Du Hao , Jin Tian , Song Yongping , Dai Yongpeng
Published: July 2019

The movements of the human body and limbs result in unique micro‐Doppler signatures, which can be exploited for classifying human activities. In this work, the authors propose a Convolutional Gated Recurrent Units Neural Network (CNN‐GRU) to classify human activities of varying duration based on micro‐Doppler spectrogram. Unlike conventional deep learning approaches which often treat the micro‐Doppler spectrogram the same way as natural image, the authors extract local feature of micro‐Doppler signatures via convolutional layer and encode temporal information with gated recurrent units. Through this unified framework, the temporal evolution of body motions within a short time can be better utilised. It avoids the resolution limitation caused by the fixed‐size time window of input data and identifies human activity of duration shorter than the time window length. The experiment shows that CNN‐GRU model is capable of recognising and temporally localising activity sequence contained in the spectrogram.
Polarisation‐space‐time adaptive processing for heterogeneous clutter suppression of airborne‐phased array radar
Authors: Sun Yuze , Yang Jian , Yang Xiaopeng
Published: July 2019

Conventional space‐time adaptive processing (STAP) achieves clutter suppression by combining spatial signals and the temporal pulses. However, extreme slow‐moving target cannot be effectively detected by space‐time joint filtering in ambiguous and non‐broadside clutter environment for airborne‐phased array radar. By increasing the polarisation information in clutter suppression, improved moving target detection performance can be obtained by the polarisation‐space‐time adaptive processing (P‐STAP). In this study, the performance of P‐STAP for airborne‐phased array radar is analysed. The polarised signal model of airborne‐phased array radar is firstly established and then clutter suppression principle of P‐STAP is derived in detailed. Afterwards, the performance of P‐STAP is investigated and compared with conventional STAP in ambiguous clutter environment. It is verified that the P‐STAP can outperform the conventional STAP for slow moving target detection by three‐domain joint processing, especially for ambiguous and non‐broadside clutter environment for airborne‐phased array radar.
Improved branch‐cut phase unwrapping strategy based on dynamic adjacent table
Authors: Liu Tiandong , Shang Zhengguo , Wu Jiabao , Zhou Dawei , Yan Shi
Published: July 2019

Phase unwrapping (PU) is a key step of interferometric SAR signal processing. The accuracy of the unwrapping phase directly affects the accuracy of the digital elevation model (DEM). The traditional path‐integral methods and global‐planning methods cannot take into account both PU accuracy and processing efficiency, and causes PU error diffusion and large‐area PU holes. To solve these problems, this study proposed an improved PU strategy based on dynamic adjacent table. For the problem of unwrapping holes that appears in traditional path‐integral methods, this study introduces improved local quality maps to guide the path‐integral operation, which effectively realises the phase compensation of the PU holes. For the low efficiency of the traditional branch‐cut algorithm, this study implements the real‐time integration path optimisation planning by further introducing the dynamic adjacent table and greatly reduces the data volume of the adjacent table. Thus, the efficiency of PU was greatly improved. Finally, the proposed method was validated by the airborne dual‐antenna interferometric SAR experimental data.
Optimal positions of translational vibration absorbers in vibroisolation of mechanical press
Authors: Łatas Waldemar
Published: July 2019

The paper deals with the problem of optimizing the positions of dynamic vibration absorbers in a mechanical press subjected to harmonic excitation force. Assuming flat motion of a rigid body and small vibrations, a discrete linear dynamic model of the press with absorbers is constructed. Using the results of numerical calculations, the optimal positions of the single or two vibration absorbers tuned to the excitation frequency, for different direction of excitation force, are obtained.
Canards Existence in the Hindmarsh–Rose model
Authors: Ginoux Jean-Marc , Llibre Jaume , Tchizawa Kiyoyuki
Published: July 2019

In two previous papers we have proposed a new method for proving the existence of “canard solutions” on one hand for three and four-dimensional singularly perturbed systems with only onefastvariable and, on the other hand for four-dimensional singularly perturbed systems with twofastvariables [J.M. Ginoux and J. Llibre,Qual. Theory Dyn. Syst.15(2016) 381–431; J.M. Ginoux and J. Llibre,Qual. Theory Dyn. Syst.15(2015) 342010]. The aim of this work is to extend this method which improves the classical ones used till now to the case of three-dimensional singularly perturbed systems with twofastvariables. This method enables to state a unique generic condition for the existence of “canard solutions” for such three-dimensional singularly perturbed systems which is based on the stability offolded singularities(pseudo singular pointsin this case) of thenormalized slow dynamicsdeduced from a well-known property of linear algebra. Applications of this method to a famous neuronal bursting model enables to show the existence of “canard solutions” in the Hindmarsh-Rose model.
Stable Carbon-Centered Radicals Based on N-Heterocyclic Carbenes
Authors: Ghadwal Rajendra S.
Published: July 2019

Carbon-centered radicals and diradicaloids based on classical N-heterocyclic carbene (NHC) scaffolds are readily accessible as crystalline solids. The presence of an aryl (Ar) substituent at the C2-position is the key to the remarkable stability of these open-shell species as it provides appropriate room for the spin-density delocalization. Two catalytic as well as high-yielding protocols have been developed to install a suitable aryl group at the C2-position of NHCs. The spin-density in mono-radicals (NHCAr)• is mostly located on the parent carbene carbon (C2) atom. The bridging of two NHCs through a phenylene spacer (C6H4)
n
enables the isolation of various p-quinodimethane (p-QDM) derivatives, which may be considered as open-shell Kekulé diradicaloids. The diradical character of these NHC-analogues of Thiele (n = 1), Chichibabin (n = 2), and Müller (n = 3) hydrocarbons [(NHC)(C6H4)
n
(NHC)] can be tuned by a rational choice of the size and/or the topology of spacers. In this account, the synthesis, structure, and properties of this new class of radical hydrocarbons is presented.

1 Introduction

2 NHC-Monoradicals

3 NHC-Diradicaloids

4 Conclusion
Surgical Repair of a Sinus of Valsalva Aneurysm: A 22-Year Single-Center Experience
Authors: Lee Jun Ho , Yang Ji-Hyuk , Park Pyo Won , Song Jinyoung , Huh June , Kang I-Seok , Jun Tae-Gook
Published: July 2019

Background Several reports described the repair of sinus of Valsalva aneurysms (SVAs); however, there is still debate regarding the optimal method of operation. We investigated the determinants of the development of significant aortic regurgitation (AR) and long-term survival after surgical repair.

Methods Between January 1995 and December 2016, 71 patients (31 females; median age: 33.3 years) underwent surgical SVA repair with (n = 60) or without (n = 11) rupture. Aortic valvuloplasty (AVP) was performed using Trusler's technique in 28 patients (39.4%), and 11 patients (15.5%) underwent aortic valve replacement during the first operation.

Results There was no early mortality, and three deaths occurred during follow-up (median: 65.4 months). Patients with grade II preoperative AR who underwent AVP tended to develop significant postoperative AR, but freedom from significant AR did not differ statistically (p = 0.387). Among patients who underwent AVP, freedom from significant AR did not differ statistically between those with grades I and II and those with grades III and IV (p = 0.460).

Conclusion Surgical repair of SVA with or without rupture can be performed safely using the dual approach technique. Concomitant aortic valve repair can be performed without difficulty and should be recommended not only for patients with moderate or severe preoperative AR (grades III and IV) but also for those with minimal or mild preoperative AR (grades I and II), whose aortic valve geometry needs correction.
Micro-Lightguide Spectrophotometry (O2C) for Lower Limb Perfusion: Effects of Exercise Walking in Claudicants
Authors: Gyldenløve Thomas , Jørgensen Lise P. , Schroeder Torben V.
Published: July 2019

Background Exercise walking has improved walking capacity in patients with intermittent claudication without affecting the macrocirculation reflected in ankle pressures. We wanted to investigate microcirculation in the skin related to exercise walking by using Micro-Lightguide Spectrophotometry (O2C).

Materials and Methods Twenty-eight patients with intermittent claudication—bilateral in 17—were included in a 12 weeks of structured home-based exercise program. The pain-free and maximal walking distances were determined on a treadmill. Saturation and flow, monitored by O2C, were examined immediately before and after the treadmill test. O2C examination took place before as well as after completion of the exercise program. Ankle–brachial index was obtained before treadmill testing.

Results As expected, walking performance improved significantly without affecting ankle pressures. Neither oxygen saturation nor flow, assessed at 2 mm depth, was affected following a 12 weeks of exercise program. We observed a significant decrease in oxygen saturation and flow upon treadmill testing in the both limbs in patients with bilateral peripheral arterial disease (PAD). In contrast, the treadmill test elicited no changes in the opposite and asymptomatic limb in patients with only unilateral PAD.

Conclusion The findings suggest that O2C may be used to study microcirculatory changes. However, it is best suited for the study of phenomena resulting in major changes as it eliminates some inherent variability.
Persistence of Reduced Left Ventricular Function after Aortic Valve Surgery for Aortic Valve Regurgitation: Bicuspid versus Tricuspid
Authors: Petersen Johannes , Neumann Niklas , Naito Shiho , Sequeira Gross Tatiana , Massel Robert , Reichenspurner Hermann , Girdauskas Evaldas
Published: July 2019

Objective Long-term prognosis of patients with aortic regurgitation (AR) and reduced left ventricular ejection fraction (LVEF) who undergo aortic valve surgery (AVS) is unknown. Due to the congenital origin, bicuspid aortic valve (BAV) morphotype might be associated with a more severe cardiomyopathy. We aimed to evaluate the LVEF recovery after aortic valve replacement (AVR) surgery in patients with AR and reduced preoperative LVEF.

Methods This retrospective analysis included 1,170 consecutive patients with moderate to severe AR who underwent AVS at our institution between January 2005 and April 2016. Preoperative echocardiography revealed 154 (13%) patients with predominant AR and baseline LVEF < 50%. A total of 60 (39%) patients had a BAV (BAV group), while the remaining 94 (61%) patients had a tricuspid morphotype (tricuspid aortic valve [TAV] group). Follow-up protocol included clinical interview using a structured questionnaire and echocardiographic follow-up.

Results A total of 154 patients (mean age 63.5 ± 12.4 years, 71% male) underwent AVS for AR in the context of reduced LVEF (mean LVEF 42 ± 8%). Fifteen (10%) patients had a severely reduced preoperative LVEF ≤ 30%. Mean STS (Society of Thoracic Surgeons) score was 1.36 ± 1.09%. Mean follow-up was comparable between both the study groups (BAV: 50 ± 40 months vs. TAV: 40 ± 38 months, p = 0.140). A total of 25 (17%) patients died during follow-up. Follow-up echocardiography demonstrated similar rate of postoperatively reduced LVEF in both groups (i.e., 39% BAV patients vs. 43% TAV patients; p = 0.638). Cox's regression analysis showed no significant impact of BAV morphotype (i.e., as compared with TAV) on the postoperative LVEF recovery (odds ratio [OR]: 1.065; p = 0.859). Severe left ventricular (LV) dysfunction at baseline (i.e., LVEF ≤ 30%) was a strong predictor for persistence of reduced LVEF during follow-up (OR: 3.174; 95% confidence interval: 1.517–6.640; p = 0.002). Survival was significantly reduced in patients with persisting LV dysfunction versus those in whom LVEF recovered (log rank: p < 0.001).

Conclusion Our study demonstrates that reduced LVEF persists postoperatively in 40 to 45% patients who present with relevant AR and reduced LVEF at baseline. Postoperative LVEF recovery is independent of aortic valve morphotype (i.e., BAV vs. TAV). Severe LV dysfunction (LVEF ≤ 30%) at baseline is a strong predictor for persistence of reduced LVEF in patients with AR and results in significantly reduced long-term survival.
Lower Lip and Chin Reconstruction with Functional Myocutaneous Gracilis Flap
Authors: Spaggiari Antonio , Benanti Elisa , Starnoni Marta , Sala Pietro , Baccarani Alessio , Santis Giorgio De
Published: July 2019

Lower lip is an important anatomical unit in daily life activities, and its proper functional and aesthetic reconstruction is crucial. In the literature, both locoregional and microsurgical flaps have been described in lower lip reconstruction. Few authors have reported lower lip reconstruction with gracilis free flap. We describe a case of wide lower lip and chin avulsion caused by human bite reconstructed with an innervated gracilis free flap raised with its overlying skin paddle. The gracilis flap was harvested with a skin paddle of 7 × 5 cm, and vascular and nervous anastomoses were performed. At 9-month follow-up, an electromyography showed high muscle activities observed in the central part of the flap, and the patient achieved good oral functions reported with daily life activities. Raising the flap with the overlying skin paddle allowed us to avoid morbidity in other donor sites, avoid scar retraction of the skin graft on the gracilis that could limit its movement, and plan aesthetical refinements such as hair transplantation or tattoo of the beard on the skin.
15.5.4 Isoquinolines (Update 2019)
Authors: Pilgrim B. S. , Tucker M. J.
Published: July 2019

This chapter is an update to the earlier Science of Synthesis contributions (Sections 15.5.1, 15.5.2, and 15.5.3) covering the synthesis and reactivity of isoquinolines, isoquinoline Noxides, and isoquinolinium salts. It focuses on the literature published in the period 2003–2016, with a particular emphasis on transition-metal-catalyzed synthetic processes.
18.12.26 Imidic Acids and Derivatives, Isoureas and Derivatives, Sulfur and Selenium Equivalents, and Analogously Substituted Methylenephosphines (Update 2019)
Authors: Podlech J.
Published: July 2019

This chapter is an update to the earlier Science of Synthesis contribution (Section 18.12) on the preparation of imidic acid derivatives and isoureas, their sulfur, selenium, and phosphorus derivatives, and on their applications in organic synthesis. It focuses on the literature published in the period 2004–2017.
Structure and dynamics in suspensions of soft core-shell colloids in the fluid regime
Authors: Pamvouxoglou Andreas , Bogri Panagiota , Nägele Gerhard , Ohno Kohji , Petekidis George
Published: July 2019

We report on a detailed experimental study of the structure and short-time dynamics in fluid-regime suspensions of soft core-shell spherical particles with different molecular weights of the chains forming the soft outer shell, and therefore different degrees of particle softness, using 3D dynamic light scattering (3D-DLS). Owing to the particle softness, the liquid-crystal coexistence regime is found to be broader than that of hard-sphere (HS) suspensions. Static light scattering in the dilute regime yields form factors that can be described using a spherical core-shell model and second virial coefficients A2 > 0 indicative of purely repulsive interactions. The particle-particle interactions are longer ranged for all considered systems except those of the smaller molecular weight chain grafted particles which show a HS-like behavior. 3D-DLS experiments in the concentrated regime up to the liquid-crystal transition provide the short-time diffusion function, D(q), in a broad range of scattering wavenumbers, q, from which the structural (cage) and short-time self-diffusion coefficients D(qm) and DS = D(q ≫ qm), respectively, are deduced as functions of the effective particle volume fraction, ϕ = c/c*, where c* is the overlap concentration, calculated using the hydrodynamic particle radius, RH. The size of the nearest-neighbor cage of particles is characterized by 2π/qm, with D(q) and the static structure factor S(q) attaining at qm the smallest and largest values, respectively. Experimental data of D(qm) and DS are contrasted with analytic theoretical predictions based on a simplifying hydrodynamic radius model where the internal hydrodynamic structure of the core-shell particles is mapped on a single hydrodynamic radius parameter γ = RH/Reff, for constant direct interactions characterized by an (effective) hard-core radius Reff. The particle softness is reflected, in particular, in the corresponding shape of the static structure factor, while the mean solvent (Darcy) permeability of the particles related to γ is reflected in the dynamic properties only. For grafted particles with longer polymer chains, D(qm) and DS are indicative of larger permeability values while particles with shorter chains are practically nonpermeable. The particle softness is also evident in the effective random close packing fraction estimated from the extrapolated zero-value limit of the cage diffusion coefficient D(qm).
AFM-tip written normal and anomalous domains in PMN-0.4PT crystals
Authors: Gainutdinov R. V. , Bodnarchuk Ya V. , Volk T. R. , Wei Xiaoyong , Liu Xin
Published: July 2019

At present, crystals of the solid solutions Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) are under intensive investigation due to their excellent piezoelectric characteristics. Studies in domain engineering are of importance for an insight into the contribution from the domain formation and resulting domain-wall density to piezoelectric coefficients. In this work, the fabrication of domains by dc AFM-tip voltages was studied in the tetragonal PMN-0.4PT crystals. Two types of domains were observed, either uniformly polarized along the poling field (the “normal” ones), or, following the commonly accepted term, “anomalous” ones containing a small area with the polarization directed oppositely to the poling field. In this work, for the first time, the correlation between the domain shape and the local piezoelectric hysteresis loops Hω−Utip was found, namely, the larger is the local bias voltage Ub, the higher is the tip voltage Utip at which the anomalous domains appear. This finding relates the observed scatter in the exposure conditions corresponding to the anomalous domains formation, to the nonuniform spatial distribution of the local bias fields. The domain diameter D vs Utip and pulse duration tp were investigated for Utip ≤ 50 V and tp from 10 ms to 10 s. The exposure characteristics are independent of the domain shape. For a given tp, D(Utip) is described by a unified linear function in the whole Utip range. The curves D(tp) follow a power law D∼tpk with the exponent k varying very weakly with Utip. The relaxation kinetics of anomalous domains depends on the writing conditions. The normal domains are found to decay significantly faster than the anomalous ones, with the decay kinetics depending on the domain spacing.
Post-processing method for extracting the resistivity of Rare-Earth Barium Copper Oxide (REBCO) coated conductors in over-critical current conditions from ultra-fast V-I pulsed current measurements
Authors: Richard S. , Sirois F. , Lacroix C.
Published: July 2019

This paper presents a simple but rigorous method to extract correctly the resistivity of the superconducting Rare-Earth Barium Copper Oxide (REBCO) layer of High Temperature Superconductor coated conductors, when the latter are characterized in over-critical current conditions using ultrafast V-I pulsed current measurements. The pulsed current measurement method is used to reduce the amount of heat generated by the strong current flowing in the sample, but it cannot prevent it completely at current levels well above the critical current. In order to estimate accurately the temperature rise, we developed the so-called “Uniform Current” (UC) model, which consists in a static current sharing model coupled with a 2D thermal solver. The model assumes that the electric field is uniform over the sample cross section. It has been shown that this hypothesis works fine at high currents, but for lower current levels, although still higher than the critical current, one must wait until the magnetic relaxation effects disappear before using the outputs of the UC model. We also derived a theoretical bound for the error related to magnetic relaxation, which can be estimated experimentally by using a rectangular pick-up coil located just above the sample surface. After applying the UC model on an experimental set of data, one obtains a whole set of data points defining the resistivity ρ(J,T) of the REBCO superconductor being characterized.
The getter effect in the Langmuir regime
Authors: D’Amico A. , Santonico M. , Lundstrom I.
Published: July 2019

The concentration of an analyte in a closed test chamber containing a chemical sensor is affected by the adsorption-desorption processes acting on the sensor surface. This phenomenon is called the “getter” whose effect has been known for many decades to occur in, e.g., vacuum tubes even if its mathematical expression has not been elaborated upon so far for affinity based chemical sensors. In this paper, we describe the “getter” equation and its consequences for affinity based chemical sensors in both the gas phase and the liquid phase with the starting point in the standard kinetic equation leading to Langmuir-like adsorption isotherms. More specifically, we calculate the “getter” isotherm and compare it with the Langmuir isotherm. The getter phenomenon is shown to be important at sufficiently small analyte concentrations (partial pressure in the gas phase or molecular concentration in the liquid phase) and in test chambers or sample cells of small volumes. A simple rule of thumb is given when the “getter” effect may be important. As an example, for a sample cell with a volume of 1 ml and a sensor surface area of 1 cm2 without a constant flow of analyte through it, the “getter” phenomenon may occur around parts per million levels for a gas sensor and around submicromolar concentrations for a sensor in a liquid. Experimental examples from the literature where the “getter” effect is observed will be given. We also show a more general electric equivalent circuit which accounts also for the getter effect by using a coverage dependent series resistance in the equivalent circuit previously suggested for Langmuir adsorption under constant partial pressure/concentration in the test chamber.
Fitting an experimental potential energy curve for the 10(0+)[43Π] electronic state of NaCs
Authors: Steely Andrew , Myers Rachel L. , Kortyna Andrew , Huennekens John , Malenda R. F. , Faust Carl
Published: July 2019

We present experimentally determined potential energy curves for the 10(0+)[43Π0] electronic state of NaCs. The 10(0+)[43Π0] state exhibits a double-minimum structure, resulting in a distinctive bound-free fluorescence signature. The perturbation facilitated optical-optical double resonance method was used to obtain Doppler-free excitation spectra corresponding to rovibrational transitions to the 10(0+)[43Π0] state. Spectroscopic constants were determined to summarize data belonging to inner well, outer well, and above the barrier regions of the electronic state. The Rydberg-Klein-Rees and inverted perturbation approach methods were used to construct a potential which reproduces the experimental rovibrational energies within a root-mean-square deviation of 2.33 cm−1. An alternative to the pointwise potential approach was also used to determine the potential energy curve by directly fitting an expanded Morse oscillator functional form. Advantages between the two approaches as they apply to double minimum wells are discussed.
Complete active space and corrected density functional theories helping each other to describe vertical electronic π → π* excitations in prototype multiple-bonded molecules
Authors: Gritsenko Oleg V. , Pernal Katarzyna
Published: July 2019

The CASΠDFT method, which combines the complete active space (CAS) wave function approach and density functional theory (DFT), offers an efficient description of important excitations to the lowest excited states. CASΠDFT employs a correlation DFT functional corrected with a function P[x] of the ratio xr of the conditional and conventional electron densities obtained with the CAS on-top pair density Π(r). The sectors of P[x] for x(r) ≤ 1 and x(r) > 1 represent the opposite effects of the suppression of dynamic correlation with nondynamic correlation and its enhancement due to the ionic-type excitation. The present combination of the self-consistent-field CAS and the corrected Lee-Yang-Parr correlation functional closely reproduces in the relatively small double-zeta basis the benchmark experimental lowest singlet vertical π → π* excitations in the prototype multiple-bonded molecules N2, CO, C2H2, and C2H4.
Photoresponse of homostructure WSe2 rectifying diode
Authors: Peng Tien-Hsin , Hong Chung-Hung , Tang Ming-Ru , Lee Si-Chen
Published: July 2019

The WSe2 homostructure rectifying diode is demonstrated, p-type and n-type WSe2 regions were formed by adopting different layer WSe2 thicknesses. Typically, the common way to fabricate two dimensional material based diode is to use heterostructure by stacking two different carrier type and band gap energies materials. However, there is always lattice mismatch at the junction, leading to the degraded photoresponse of the diodes. In order to reduce the problems of heterostructure diode, layer thickness dependent band gap energy of WSe2 is reported and applied to fabricate homostructure diode. The ideality factor of the current-voltage characteristic is 1.64 and the current rectification ratio can reach to 103. The optical properties of the diode, including fill factor 45.7%, responsivity 16.02 mA/W and EQE 3.06% are reported. It is concluded that the WSe2 homojunction diode can be applied in photodetectors, switches, solar cells etc.
Green hydrogen and the future of sustainable energy use in South Africa
Authors: Mandel Savannah
Published: July 2019

Renewably-sourced hydrogen brings a positive outlook to the South African energy sector — one of the highest ranking greenhouse gas emitters in the world.
Shockwaves from pulsed streamer discharge imaged at ultra-high speeds
Authors: Johnson-Groh Mara
Published: July 2019

A high-speed camera system revealed the individual shockwaves created by a pulsed electrical discharge in water, unveiling some of the fundamental physics.
Intercultural pragmatics and the translation of English interjections and expletives into Spanish and Chinese
Authors: Qin Huang , Valdeón Roberto A.
Published: July 2019

This article aims to discuss the importance of pragmatics in translation, paying particular attention to the difficulties posed by two non-clausal units or inserts (Biber et al. 1999). These elements have been classified into nine categories, namely interjections, greetings and farewells, discourse markers, attention signals, response elicitors, response forms, hesitators, polite formulae and expletives. In this article we will discuss two of them, interjections and expletives, both of which express stance. We will consider the possible renderings of these elements in Spanish and Chinese and the difficulties they pose in the translation of fictional dialogue in connection with previous research into this issue in order to identify future lines of enquiry. As regards the translation of expletives, it seems that recent publications point towards a greater presence of swearwords in Spanish dubbed versions than in the past, referred to in this article as a “vulgarization hypothesis”.
A metaphor-based account of semantic relations among proverbs
Authors: Lemghari El Mustapha
Published: July 2019

The paper deals with semantic relations in the field of proverbs from the standpoint of Conceptual Metaphor Theory. Our main claim is that proverb understanding is conceptually complex, involving many construal operations, namely metaphor. Metaphor is assumed to play a crucial role in framing and relating proverbs to one another via various semantic relationships. Three semantic relations will be highlighted: synonymy, antonymy and polysemy. Synonymous proverbs will be shown to be structured by similar metaphors, whereas antonymous proverbs by contradictory metaphors. As regards polysemous proverbs, our focus will be on a specific polysemy, consisting of contradictory meanings. Overall, we will attempt to build a cognitive model for proverbs semantic relationships, based on three main assumptions: first, proverbs have relatively stable meaning. Second, rather than sharply distinct, conventionalized meaning and contextual meaning of proverbs form a continuum, residing in their common conceptual base. Third, such a common conceptual base is metaphor-dependent.
How do Saudis complain?
Authors: El-Dakhs Dina Abdel Salam , Al-Haqbani Jawaher Nasser , Althaqafi Manal A. , Al-Fouzan Shorouq
Published: July 2019

The current study adopts a dialogue-analytic approach to the examination of complaint behavior in Saudi Arabic as spoken in the Najd region, the central region of the Kingdom of Saudi Arabia. To this end, role-plays with 120 Saudi nationals who are Najdi-speakers were recorded and transcribed. Statistical comparisons revealed that Najdis used a variety of complaint strategies with requests for repair, expressing annoyance and providing modified blame being the most frequent. Najdis also produced a large number of initiators and internal and external modifiers, mainly to mitigate the negative force of complaints. Although a small influence was found for gender, the variables of age, social distance and social dominance showed a strong influence on the Najdis’ complaint behavior. The results are discussed in light of relevant theoretical models and the existing literature.
A Proof of First Digit Law from Laplace Transform*
Authors: Cong Mingshu , Ma Bo-Qiang
Published: July 2019

The first digit law, also known as Benford’s law or the significant digit law, is an empirical phenomenon that the leading digit of numbers from real world sources favors small ones in a form log(1 + 1/d), where d = 1, 2,…, 9. Such a law has been elusive for over 100 years because it has been obscure whether this law is due to the logical consequence of the number system or some mysterious mechanism of nature. We provide a simple and elegant proof of this law from the application of the Laplace transform, which is an important tool of mathematical methods in physics. It is revealed that the first digit law originates from the basic property of the number system, thus it should be attributed as a basic mathematical knowledge for wide applications.
Experimental Point-to-Multipoint Plug-and-Play Measurement-Device-Independent Quantum Key Distribution Network*
Authors: Tang Guang-Zhao , Sun Shi-Hai , Li Chun-Yan
Published: July 2019

Measurement-device-independent quantum key distribution (MDI-QKD) offers a practical way to realize a star-type quantum network. Previous experiments on MDI-QKD networks can only support the point-to-point communication. We experimentally demonstrate a plug-and-play MDI-QKD network which can support the point-to-multipoint communication among three users. Benefiting from the plug-and-play MDI-QKD architecture, the whole network is automatically stabilized in spectrum, polarization, arrival time, and phase reference. The users only need the encoding devices, which means that the hardware requirements are greatly reduced. Our experiment shows that it is feasible to establish a point-to-multipoint MDI-QKD network.
Programmable Quantum Processor with Quantum Dot Qubits
Authors: Chen Yao , Lin Fo-Liang , Liang Xi , Jiang Nian-Quan
Published: July 2019

The realization of controllable couplings between any two qubits and among any multiple qubits is the critical problem in building a programmable quantum processor (PQP). We present a design to implement these types of couplings in a double-dot molecule system, where all the qubits are connected directly with capacitors and the couplings between them are controlled via the voltage on the double-dot molecules. A general interaction Hamiltonian of n qubits is presented, from which we can derive the Hamiltonians for performing operations needed in building a PQP, such as gate operations between arbitrary two qubits and parallel coupling operations for multigroup qubits. The scheme is realizable with current technology.
Measurement of S-Wave Scattering Length between 6Li and 88Sr Atoms Using Interspecies Thermalization in an Optical Dipole Trap*
Authors: Ma Xiao-Bin , Ye Zhu-Xiong , Xie Li-Yang , Guo Zhen , You Li , Tey Meng Khoon
Published: July 2019

We report the creation of the first mixture of 6Li and 88Sr atoms in an optical dipole trap. Using this mixture, a measurement of the interspecies thermalization process is carried out and the previously unknown interspecies s-wave scattering length between 6Li and 88Sr atoms is extracted to be

|

a

6

L
i

−

88

S
r

|
=
(

380

−
100

+
160

)

a
0

with a0 being the Bohr radius from the rate of interspecies thermalization.
Spatial Characteristics of Thomson Scattering Spectra in Laser and Magnetic Fields*
Authors: Zhao Li , Chen Zhi-Jing , Sang Hai-Bo , Xie Bai-Song
Published: July 2019

Spatial characteristics of Thomson scattering spectra are studied for an electron moving in the circularly polarized laser field in the presence of a strong uniform magnetic field. The results show that the angular distributions of the spectra with respect to the azimuthal and polar angles exhibit different symmetries, respectively, which depend on the fields and electron parameters sensitively and significantly. Moreover, for relatively large parameters such as high laser intensity, high magnetic resonance parameter as well as large initial momentum of electron, the two lobes in spectra tend to the laser-propagating direction so that the radiation can be collimated in the forward direction. Furthermore, an important finding is that by choosing the appropriate fields and initial momentum of electron, the high frequency part of the Thomson scattering spectra can reach the frequency range of soft x-ray, in which a high radiation power per solid angle as ∼1011 a.u. can be obtained.
A 1 kHz Fe:ZnSe Laser Gain-Switched by a ZnGeP2 Optical Parametric Oscillator at 77 K*
Authors: Li Ying-Yi , Yang Ke , Liu Gao-You , Xu Li-Wei , Yao Bao-Quan , Ju You-Lun , Dai Tong-Yu , Duan Xiao-Ming
Published: July 2019

We demonstrate a Fe:ZnSe laser gain-switched by a 2.9 μm ZnGeP2 optical parametric oscillator under pulse repetition frequency of 1 kHz at liquid nitrogen temperature of 77 K. The maximum output power is 63 mW with pulse duration of 34.4 ns. The wavelength covers 3686.6–4088.6 nm and centers at 3897.7 nm. The output power decreases with increasing the temperature of the crystal in 77–222 K.
Spin Transport under In-plane Electric Fields with Different Orientations in Undoped InGaAs/AlGaAs Multiple Quantum Wells*
Authors: Xue Xiao-di , Liu Yu , Zhu Lai-pan , Huang Wei , Zhang Yang , Zeng Xiao-lin , Wu Jing , Xu Bo , Wang Zhan-guo , Chen Yong-hai , Zhang Wei-feng
Published: July 2019

The spin-polarized photocurrent is used to study the in-plane electric field dependent spin transport in undoped InGaAs/AlGaAs multiple quantum wells. In the temperature range of 77–297 K, the spin-polarized photocurrent shows an anisotropic spin transport under different oriented in-plane electric fields. We ascribe this characteristic to two dominant mechanisms: the hot phonon effect and the Rashba spin-orbit effect which is influenced by the in-plane electric fields with different orientations. The formulas are proposed to fit our experiments, suggesting a guide of potential applications and devices.
Observation of Two-Level Critical State in the Superconducting FeTe Thin Films*
Authors: Ru Hao , Lin Yi-Shi , Chen Yin-Cong , Feng Yang , Wang Yi-Hua
Published: July 2019

FeTe, a non-superconducting parent compound in the iron-chalcogenide family, becomes superconducting after annealing in oxygen. Under the presence of magnetism, spin-orbit coupling, inhomogeneity and lattice distortion, the nature of its superconductivity is not well understood. Here we combine the mutual inductance technique with magneto transport to study the magnetization and superconductivity of FeTe thin films. It is found that the films with the highest T
C
show non-saturating superfluid density and a strong magnetic hysteresis distinct from that in a homogeneous superconductor. Such a hysteresis can be well explained by a two-level critical state model and suggests the importance of granularity to superconductivity in this compound.
Magnetization of Co-Fe-Ta-B-O Amorphous Thin Films*
Authors: Xiong Chengyue , Chen Cheng , Sun Wen , Lu Ziyao , Mou Hongming , Zhang Xiaozhong
Published: July 2019

An amorphous magnetic material system (Co
20
Fe
47
Ta
20
B
13)1–x

O

x

is fabricated by magneto sputtering. Three stages of magnetization behavior exist when oxygen content changes in the system. As the oxygen increases, the absence of percolation effect of magnetic nano-particles makes the multi-domain structure broken so that high coercivity appears in the samples with proper oxygen content. A temperature-dependent Stoner–Wohlfarth model is used to explain the magnetization properties at relatively high temperature. Magnetizations with magnetic field in and out of the sample plane are also investigated to prove the mechanisms. This work provides a systematic study of a new kind ofv amorphous magnetic system and is helpful for us to know more about this type of material.
Mechanism for the Self-Assembly of Hollow Micelles from Rod-Coil Block Copolymers
Authors: Zhang Lingyun
Published: July 2019

The mechanism for the self-assembly of hollow micelles from rod-coil diblock copolymers is proposed. In a coil-selective solvent, the diblock copolymers self-assemble into a layered structure. It is assumed that the rigid rods form an elastic shell whose properties are dictated by a bending energy. For a hollow micelle, the coils outside the micelle form a brush, while the coils inside the micelle can be in two different states, a brush or an adsorption layer, corresponding to symmetric or asymmetric configurations, respectively. The total energy density of a hollow micelle is calculated by combining the interfacial energy, elastic bending energy and the stretching energy of the brushes. For the asymmetric configuration with a polymer brush on one side, the competition between the elastic bending energy and the brush stretching energy leads to a finite spontaneous curvature, stabilizing hollow spherical micelles. Comparison of the free energy density for different geometries demonstrates that transitions for the different geometry micelles are controlled by the degree of polymerization of the coils and the length of the rods. These results are in agreement with the experimental results.
A New Effect of Oxygen Plasma on Two-Dimensional Field-Effect Transistors: Plasma Induced Ion Gating and Synaptic Behavior*
Authors: Guo Cheng-Lei , Wang Bin-Bin , Xia Wei , Guo Yan-Feng , Xue Jia-Min
Published: July 2019

Plasma treatment is a powerful tool to tune the properties of two-dimensional materials. Previous studies have utilized various plasma treatments on two-dimensional materials. We find a new effect of plasma treatment. After controlled oxygen-plasma treatment on field-effect transistors based on two-dimensional SnSe
2
, the capacitive coupling between the silicon back gate and the channel through the 300nm SiO
2
dielectric can be dramatically enhanced by about two orders of magnitude (from 11 nF/cm
2
to 880 nF/cm
2
), reaching good efficiency of ion-liquid gating. At the same time, plasma treated devices show large hysteresis in the gate sweep demonstrating memory behavior. We reveal that this spontaneous ion gating and hysteresis are achieved with the assistance of a thin layer of water film automatically formed on the sample surface with water molecules from the ambient air, due to the change in hydrophilicity of the plasma treated samples. The water film acts as the ion liquid to couple the back gate and the channel. Thanks to the rich carrier dynamics in plasma-treated two-dimensional transistors, synaptic functions are realized to demonstrate short- and long-term memories in a single device. This work provides a new perspective on the effects of plasma treatment and a facile route for realizing neuromorphic devices.
Branched flow and caustics in nonlinear waves
Authors: Green Gerrit , Fleischmann Ragnar
Published: July 2019

Rogue waves, i.e. high amplitude fluctuations in random wave fields, have been studied in several contexts, ranging from optics via acoustics to the propagation of ocean waves. Scattering by disorder, like current fields and wind fluctuations in the ocean, as well as nonlinearities in the wave equations provide widely studied mechanisms for their creation. However, the interaction of these mechanisms is largely unexplored. Hence, we study wave propagation under the concurrent influence of geometrical (disorder) and nonlinear focusing in the (current-modified) nonlinear Schrödinger equation. We show how nonlinearity shifts the onset distance of geometrical (disorder) focusing and alters the peak intensities of the fluctuations. We find an intricate interplay of both mechanisms that is reflected in the observation of optimal ratios of nonlinearity and disorder strength for the generation of rogue waves.
X-ray activity from different types of stars
Authors: He Lin , Wang Song , Xu Xiao-Jie , Soria Roberto , Liu Ji-Feng , Li Xiang-Dong , Bai Yu , Bai Zhong-Rui , Guo Jin-Cheng , Qiu Yan-Li , Zhang Yong , Xu Ruo-Chuan , Qian Ke-Cheng
Published: July 2019

X-ray emission is an important indicator of stellar activity. In this paper, we study stellar X-ray activity using the XMM-Newton and LAMOST data for different types of stars. We provide a sample including 1259 X-ray-emitting stars, of which 1090 have accurate stellar parameter estimations. Our sample size is much larger than those used in previous works. We find a bimodal distribution of the X-ray to optical flux ratio (log(f
X/fV
)) for G and K stars. We interpret that this bimodality is due to two subpopulations with different coronal heating rates. Furthermore, using the full widths at half maxima calculated from Hα and Hβ lines, we show that these stars in the inactive peaks have smaller rotational velocities. This is consistent with the magnetic dynamo theory that presumes stars with low rotational velocities have low levels of stellar activity. We also examine the correlation between log(f
X/fV
) and luminosity of the excess emission in the Hα line, and find a tight relation between the coronal and chromospheric activity indicators.