bluuebunny/crossref_metadata_2025 huggingface dataset:
Synergy of two lower hybrid waves with different frequencies on EAST
Authors: Zhai X. M. , Chen J. L. , Xiang N. , Bonoli P. T. , Shiraiwa S.
Published: May 2019

Lower hybrid current drive (LHCD) is one of the major approaches maintaining long pulse discharges on EAST. There are two lower hybrid (LH) systems on EAST launching waves at 4.6 GHz and 2.45 GHz into the plasma, respectively, and the input power of the 4.6 GHz wave is typically dominant. In this work, the synergy of the two waves and the modification of the power deposition of the 4.6 GHz wave by coupling the 2.45 GHz wave are investigated theoretically. According to the phase space analysis, the wave propagation domains of the two LH waves always overlap substantially with each other for typical LHCD experimental parameters on EAST, indicating that the coupling between them might be strong. Ray-tracing/Fokker-Planck simulations for a LH current drive experiment on EAST show that the change of the power deposition profile due to the coupling could be understood by the rise and fall of the tails of the parallel electron distribution functions on different flux surfaces. If either the injected wave power at 2.45 GHz is comparable with that at 4.6 GHz or the incident N∥ of the 2.45 GHz wave reaches a high value (e.g., 5.7/Te,0), the power deposition profile of the 4.6 GHz wave can be modified greatly due to the coupling with the 2.45 GHz wave. With the parameters compatible with the ability of the LH wave system on EAST, injection of the 2.45 GHz wave can still modify the power deposition profile of the 4.6 GHz wave significantly by combining those two approaches. Finally, it is shown how a 4.6 GHz wave which cannot be Landau damped when injected alone is absorbed in low density plasmas with a magnetic shear reversal configuration in the presence of a 2.45 GHz wave.
Ab initio simulation studies on the room-temperature ferroelectricity in two-dimensional
β
-phase GeS
Authors: Yin Huabing , Liu Chang , Zheng Guang-Ping , Wang Yuanxu , Ren Fengzhu
Published: May 2019

Stable ferroelectricity with an in-plane spontaneous polarization of 2.00 × 10−10 C/m is found in two-dimensional (2D) β-GeS monolayers from theoretical calculations, which can be effectively tuned by the applied tensile strains. The Curie temperature of the monolayer is evaluated to be 358 K by ab initio molecular dynamics simulations. Remarkably, the 2D ferroelectricity is found to exist in 2D few-layer β-GeS nanosheets which could be synthesized in experiments. The strong spontaneous polarization and giant pyroelectric coefficient accompanied by the appearance of phase transition near room temperature facilitate the development of β-GeS monolayers or nanosheets for applications in ferroelectric, pyroelectric, and piezoelectric devices with superior performance.
Spin-orbit torque switching in perpendicular Y3Fe5O12/Pt bilayer
Authors: Guo C. Y. , Wan C. H. , Zhao M. K. , Wu H. , Fang C. , Yan Z. R. , Feng J. F. , Liu H. F. , Han X. F.
Published: May 2019

All electrical manipulation of magnetization in an Y3Fe5O12 (YIG)/Pt system was crucial to develop magnon-based spintronic devices. In this study, we realized spin–orbit torque (SOT) switching in perpendicular YIG/Pt films. Perpendicular magnetic anisotropy of YIG was induced by strain from the bottom substrate and also influenced by the capping Pt layer and subsequent annealing. Besides, SOT efficiency of the YIG/Pt system was also measured. Damping-like torque with an efficiency of 0.98 Oe/(MA/cm2) was the dominating term to contribute to the SOT switching. This work was beneficial to construct electrically controllable magnon devices.
Translating mouthwash use for gonorrhoea prevention into a public health campaign: identifying current knowledge and research gaps
Authors: Chow Eric P. F. , Maddaford Kate , Trumpour Sabrina , Fairley Christopher K.
Published: May 2019

The gonorrhoea rate among gay and bisexual men who have sex with men (MSM) has been increasing rapidly in many Western countries. Furthermore, gonorrhoea is becoming increasingly resistant to antibiotics and only limited options remain for treatment. Recent evidence suggests that the oropharynx may play an important role in gonorrhoea transmission. It is hypothesised that reducing the prevalence of oropharyngeal gonorrhoea will also reduce the population incidence of gonorrhoea. Mouthwash has been proposed as a novel non-antibiotic intervention to prevent oropharyngeal gonorrhoea; hence, reducing the probability of antibiotic resistance developing. However, its efficacy is yet to be confirmed by a randomised controlled trial – the findings of which will be available in 2019. If the trial shows mouthwash is effective in preventing gonorrhoea, this finding could potentially be translated into a public health campaign to increase the mouthwash use in the MSM population. This article summarises the current evidence of the effectiveness of mouthwash against gonorrhoea and discusses the potential literature gaps before implementing the mouthwash intervention at a population level.
Bacterial scattering in microfluidic crystal flows reveals giant active Taylor–Aris dispersion
Authors: Dehkharghani Amin , Waisbord Nicolas , Dunkel Jörn , Guasto Jeffrey S.
Published: May 2019

Significance

The fluid habitats of swimming microbes are characterized by heterogeneous flow, typical of groundwater and marine turbulence, which can augment cell transport in unexpected ways and affect important processes ranging from biogeochemical cycling to disease transmission. Following in the footsteps of century-old light diffraction techniques, the scattering of bacteria in microfluidic crystal flows reveals how cell shape and motility couple to hydrodynamic gradients, giving rise to observed filamentous cell density patterns. Consequently, hindered bacterial mobility transverse to the flow greatly enhances downstream dispersal. These results illustrate the stark contrast of active matter transport with passive Brownian particles and may provide insights into microbial ecosystems, biomedical device design, and the guidance of swimming microrobots.
Ammonia generation by tryptophan synthase drives a key genetic difference between genital and ocular
Chlamydia trachomatis
isolates
Authors: Sherchand Shardulendra P. , Aiyar Ashok
Published: May 2019

A striking difference between genital and ocular clinical isolates of
Chlamydia trachomatis
is that only the former express a functional tryptophan synthase and therefore can synthesize tryptophan by indole salvage. Ocular isolates uniformly cannot use indole due to inactivating mutations within tryptophan synthase, indicating a selection against maintaining this enzyme in the ocular environment. Here, we demonstrate that this selection occurs in two steps. First, specific indole derivatives, produced by the human gut microbiome and present in serum, rapidly induce expression of
C. trachomatis
tryptophan synthase, even under conditions of tryptophan sufficiency. We demonstrate that these indole derivatives function by acting as de-repressors of
C. trachomatis
TrpR. Second,
trp
operon de-repression is profoundly deleterious when infected cells are in an indole-deficient environment, because in the absence of indole, tryptophan synthase deaminates serine to pyruvate and ammonia. We have used biochemical and genetic approaches to demonstrate that expression of wild-type tryptophan synthase is required for the bactericidal production of ammonia. Pertinently, although these indole derivatives de-repress the
trpRBA
operon of
C. trachomatis
strains with
trpA
or
trpB
mutations, no ammonia is produced, and no deleterious effects are observed. Our studies demonstrate that tryptophan synthase can catalyze the ammonia-generating β-elimination reaction within any live bacterium. Our results also likely explain previous observations demonstrating that the same indole derivatives inhibit the growth of other pathogenic bacterial species, and why high serum levels of these indole derivatives are favorable for the prognosis of diseased conditions associated with bacterial dysbiosis.
Enhanced susceptibility to chemically induced colitis caused by excessive endosomal TLR signaling in LRBA-deficient mice
Authors: Wang Kuan-wen , Zhan Xiaoming , McAlpine William , Zhang Zhao , Choi Jin Huk , Shi Hexin , Misawa Takuma , Yue Tao , Zhang Duanwu , Wang Ying , Ludwig Sara , Russell Jamie , Tang Miao , Li Xiaohong , Murray Anne R. , Moresco Eva Marie Y. , Turer Emre E. , Beutler Bruce
Published: May 2019

Significance

IBD is one of the most common early manifestations of LRBA deficiency and has been attributed to impaired regulatory T cell function. However, whether other immune cell types also contribute has not been comprehensively tested. We found that, in LRBA-deficient mice, DCs contribute significantly to colitis in the DSS model. We also showed that blocking innate immune signaling from the endosomal TLRs, TLR3, TLR7, and TLR9, inLrba−/−mice dramatically reduced their susceptibility to DSS-induced colitis. Our data indicate a role for LRBA in limiting endosomal TLR signaling and suggest that elevated IRF3 and IRF7 activation leading to increased expression of inflammatory chemokines promotes excessive intestinal inflammation in LRBA-deficient mice.
Casein kinase 1 family regulates PRR5 and TOC1 in the Arabidopsis circadian clock
Authors: Uehara Takahiro N. , Mizutani Yoshiyuki , Kuwata Keiko , Hirota Tsuyoshi , Sato Ayato , Mizoi Junya , Takao Saori , Matsuo Hiromi , Suzuki Takamasa , Ito Shogo , Saito Ami N. , Nishiwaki-Ohkawa Taeko , Yamaguchi-Shinozaki Kazuko , Yoshimura Takashi , Kay Steve A. , Itami Kenichiro , Kinoshita Toshinori , Yamaguchi Junichiro , Nakamichi Norihito
Published: May 2019

The circadian clock provides organisms with the ability to adapt to daily and seasonal cycles. Eukaryotic clocks mostly rely on lineage-specific transcriptional-translational feedback loops (TTFLs). Posttranslational modifications are also crucial for clock functions in fungi and animals, but the posttranslational modifications that affect the plant clock are less understood. Here, using chemical biology strategies, we show that the
Arabidopsis
CASEIN KINASE 1 LIKE (CKL) family is involved in posttranslational modification in the plant clock. Chemical screening demonstrated that an animal CDC7/CDK9 inhibitor, PHA767491, lengthens the
Arabidopsis
circadian period. Affinity proteomics using a chemical probe revealed that PHA767491 binds to and inhibits multiple CKL proteins, rather than CDC7/CDK9 homologs. Simultaneous knockdown of
Arabidopsis
CKL-encoding genes lengthened the circadian period. CKL4 phosphorylated transcriptional repressors PSEUDO-RESPONSE REGULATOR 5 (PRR5) and TIMING OF CAB EXPRESSION 1 (TOC1) in the TTFL. PHA767491 treatment resulted in accumulation of PRR5 and TOC1, accompanied by decreasing expression of PRR5- and TOC1-target genes. A
prr5 toc1
double mutant was hyposensitive to PHA767491-induced period lengthening. Together, our results reveal posttranslational modification of transcriptional repressors in plant clock TTFL by CK1 family proteins, which also modulate nonplant circadian clocks.
Protective role for the N-terminal domain of α-dystroglycan in Influenza A virus proliferation
Authors: de Greef Jessica C. , Slütter Bram , Anderson Mary E. , Hamlyn Rebecca , O’Campo Landa Raul , McNutt Ellison J. , Hara Yuji , Pewe Lecia L. , Venzke David , Matsumura Kiichiro , Saito Fumiaki , Harty John T. , Campbell Kevin P.
Published: May 2019

Significance

Influenza A virus (IAV) is a major cause of respiratory infections. We show that mice lacking the N-terminal domain of α-dystroglycan (α-DGN) exhibit significantly higher viral titers in the lungs after IAV infection. In addition, we show that overexpression of α-DGN in the lungs, both prior and during IAV infection, significantly reduces viral load and that recombinant α-DGN disrupts hemagglutination mediated by the influenza virus. Collectively, we uncover a protective role for α-DGN in IAV proliferation, suggesting it may have antiviral properties and could potentially be used as a treatment for IAV infection. As α-DGN levels are altered in more (inflammatory) disease states, this insight opens new avenues of investigation into the role of α-DGN in inflammation.
Deconstructing markedness in sound change typology
Authors: Blevins Juliette
Published: May 2019

Many sound changes have been attributed to misperception (Ohala 1981, 1993). When two sounds A and B are perceptually similar, A can be misperceived as B and vice versa. One sound change attributed solely to perceptual similarity is θ > f (Blevins 2004). Misperception of [θ] as [f] yields θ > f, while hearing [f] as [θ] should lead to f > θ changes. Context-free shifts of θ > f are attested, but regular f > θ changes are rare. Recent research questions the existence of f > θ changes and the perceptual basis of θ > f changes. Historical, typological, experimental, developmental, and language contact data reviewed here support the original perceptual account of θ > f and f > θ, suggesting that the observed asymmetry can be explained phonetically and structurally, without reference to markedness (cf. Andersen 2008).
Grammaticalization and degrammati(calizati)on in the development of the Iranian verb system
Authors: Bubenik Vit
Published: May 2019

The present article contributes to the current theoretical discussions regarding the issues of grammaticalization, degrammati(calizati)on and reanalysis as practiced by scholars working predominantly in West European, Greek and Slavic languages. It brings into discussion relatively under-represented data from the West Iranian languages by surveying fundamental morphological and syntactic changes observable in the development of the verb systems of Persian, Tajik, Kurdish and Balochi: (i) the realignment of the Old Persian possessive construction as the finite verb form in Middle Persian, (ii) the establishment of the analytic Perfect in Early New Persian, (iii) degrammati(calizati)on of the copula in the Perfect aspect in Kurdish and Balochi, (iv) grammaticalization of the adverb hamēw ‘always’ as the Imperfect marker in Early New Persian, (v) the formation of the modal future tense in New Persian, and (vi) the role of grammaticalization and degrammati(calizati)on in the renewal of the passive diathesis in Early New Persian.
From preverbal to postverbal in the early history of Japanese
Authors: Frellesvig Bjarke
Published: May 2019

Old Japanese (largely 8th century AD; “OJ”) is, like Middle and Modern Japanese, a typical SOV language and also shares with them a complex predicate construction consisting of two adjacent verbs, V1 V2, of which V2 has some grammatical function, (i). However, OJ in addition has a complex predicate construction in which V1 is grammatical and V2 is the main verb, (ii), which seems anomalous in an SOV language and which is not found in Middle or Modern Japanese.

(i)

NJ nomi-au
(lit. ‘drink-meet’) ‘drink together’

(ii)

OJ
api nomu (lit. ‘meet drink’) ‘drink together’

Situated within a classical version of Henning Andersen’s language change theory, this paper offers a diachronic interpretation of the OJ construction in (ii) as a transient stage in the emergence of the complex predicate construction in (i), which may be understood as having arisen through categorial reinterpretation of preverbal adverbial material as grammatical, reflected in (ii), followed by a structurally motivated shift to postverbal position, reflected in (i). This proposal is further generalized to account for several grammatical suffixes in Japanese as having originated in similar sets of innovations, specifically the prohibitive final particle na, negative -(a)n-, conjectural -(a)m-, necessitive be‑ and negative potential masizi.
From a single lexical unit to multiple grammatical paradigms
Authors: Kragh Kirsten Jeppesen , Schøsler Lene
Published: May 2019

This paper studies the reanalysis, grammaticalisation, and paradigmatization of constructions becoming members of grammatical paradigms. The changes are illustrated by means of a single lexical unit, i.e. the French verb of perception, voir “to see”. The verb is found in very different contexts, which have been reanalysed and resulted in grammaticalized structures. Therefore, voir provides an interesting illustration of the pathway of a lexical unit into grammar. One reanalysis has resulted in the creation of voir followed by the deictic relative as part of a marker of progression, i.e. as a member of the category of tense, aspect, and mood. Another pathway involves the imperative form of the verb, which has grammaticalized as presentatives (voici and voilà). These forms have undergone further grammaticalization or, following the terms of Henning Andersen, regrammation, into markers of focalization.
Morphosyntactic reanalysis in Australian languages
Authors: Koch Harold
Published: May 2019

This paper discusses three examples of reanalysis in the Pama-Nyungan languages of Australia, affecting word, clause, and sentence level constructions respectively. The elimination of a morpheme boundary, with absorption of an erstwhile suffix into the nominal stem, in Western Desert dialects revisits and amplifies earlier discussion from Koch (1995), canvassing various motivations and finding supporting data more recent data from Langlois (2004). Secondly, the gradual implementation of the effects of a change from ergative to accusative alignment in Panyjima, as established by Dench (1982), are explored within Andersen’s framework of actualisation. The third study shows, on the basis of the etymology of formal markers, how, in the Arandic languages, biclausal structures have developed via auxiliarisation into inflectional markers of imperfective aspect, but also into a set of inflections realising contrasting values within a new morphosyntactic category of “associated motion”. This section articulates the diachronic developments behind the synchronic system, building on earlier suggestions by Koch (1984) and Wilkins (1991).
Suppletion or illusion?
Authors: Nichols Johanna
Published: May 2019

Constructing a typology and cross-linguistic survey for Aktionsart, actionality, and related notions is largely infeasible at present because so few Aktionsart systems have been fully described, they are typically complex and intricately dependent on verbal semantics and classification, and despite the inherent connection to the lexicon information about Aktionsart categories is rarely recoverable from dictionaries. As a first step this paper proposes a very minimal distinction of continuous (lacking inherent endpoints, chiefly states and activities) vs. bounded (having one or more endpoints, e.g. punctual, telic, and ingressive predicates and subtypes such as accomplishments and achievements). The word family of a predicate like sit can be based on the continuous form (as in English, where continuous sit is the base and sit down is derived) or on the bounded form (e.g. Slavic *sed- ‘sit down’ and derivative *sid-e-). A stumbling block in this endeavor has been sets like continuous know: bounded find out realize, etc. where no regular derivation relates the forms. Are they a paradigm? If so, what is the base? Structuralist criteria and Andersen's notion of markedness agreement indicate that they do form a paradigm and the continuous form is the base.
Changing attitudes to female genital mutilation: an integrative research review of recent literature on FGM in Nigeria.
Authors: Owojuyigbe M. A.
Published: May 2019

In Nigeria, 19.9 million girls and women aged between 15 and 49 years underwent female genital mutilation (FGM) between 2004 and 2015, making it a red-flag nation in terms of the practice. The paper notes the issues of bodily, medical, sexual and psychological harm and disability associated with the practice of FGM, and reviews societal attitudes to the practice of the subject in Nigeria as portrayed by the literature, especially in light of recent intervention efforts by different tiers of government, and non-governmental organizations, employing an integrative research review of 14 published articles on the subject, and concludes that changes in attitude to the practice in Nigeria have not been as significant as statistics suggest.
Gender and nutrition security.
Authors: Niehof A.
Published: May 2019

Many studies on nutrition that include gender do not take it further than observing male-female differences. In this review, I use the concept in the sociological sense and I conceptualize nutrition as embedded in household food security and pertaining to (gendered) performances that require resources. Using both quantitative data on associations and trends as well as qualitative findings that reveal mechanisms and subjectivities, I structure the discussion along three subject clusters of gender-nutrition interfaces, i.e. 'women's nutrition and gender inequalities'; 'food care'; and 'sons and daughters'. Regarding the first cluster, I found that because of women's hegemonic role in family food care and their often being relationally defined as mothers, their own nutritional needs tend to be considered instrumentally rather than as a matter in its own right. Gender inequalities affect women's nutrition through unfavourable intra-household food distribution patterns and poor access to crucial resources such as safe water and health care. They have an impact on women's care-giving abilities, and cause unequal treatment of sons and daughter. There is ample evidence that gender inequalities can propel an intergenerational cycle of female undernutrition. Because of the inequalities' entrenchment in daily life and in institutional frameworks, there are no easy solutions. However, female education (typically referred to as 'maternal' education) has been proven to alleviate the undernutrition of women and children. Finally, I conclude that gender inequality is a neglected aspect in defining sustainable nutrition and the relationship between women's nutrition and their reproductive rights a missing topic in the literature.
Fabrication of novel binderless anode via electrophoretic deposition for HT-PEMFC
Authors: Jabbari Zeinab , Nassernejad Bahram , Fallah Narges , Javanbakht Mehran , Afsham Neda
Published: May 2019

We report a simple strategy to fabricate electrodes for high temperature electrolyte membrane fuel cell (HT-PEMFC) by eliminating binder. The Electrophoretic Deposition (EPD) method was used to fabricate the Gas Diffusion Electrode (GDE) in the absence of the binder. For comparison, the same catalyst ink was used to make hand-spray binderless electrode, and both electrodes used as anodes for Membrane Electrode Assemblies (MEAs) in a HT-PEMFC operating at 140°C. XRD and SEM were used to investigate the microstructure and morphology of GDEs. The ECSA was studied, and CO oxidation and desorption were evaluated. Results indicated proper attachment of electrocatalyst on GDL and better results for CO oxidation and desorption, when binderless EPD method was used. The maximum power density 180 mW cm−2 was obtained for MEA prepared by binderless EPD method. Comparing these results by other works indicate that the binderless EPD electrode could be utilised as the anode for HT-PEMFC.
Regional management and biodiversity conservation in GIAHS: text analysis of municipal strategy and tourism management
Authors: Kohsaka Ryo , Matsuoka Hikaru , Uchiyama Yuta , Rogel Marie
Published: May 2019

Purpose of the research: 
To identify the gaps between the rhetoric and reality of the role of citizen participation and its role in maintenance and monitoring of heritages and resources (including biodiversity monitoring), we analyzed the discourse of Globally Important Agricultural Heritage System (GIAHS) at municipality level.

Methods:
 As an analytical framework, text mining is applied to interviews of officers at the municipal level of GIAHS in Noto which was amongst the first sites in Japan. The identification of such gap is critical for sustainability and to prevent conflicts from tourism, agriculture or educations.

Results:
 The results reveal that (1) there is a gap between the official goals of that designation at the international level and local needs, (2) role of citizens is emphasized in the applications and action plans at rhetorical level but remain rather limited in practice and that (3) municipalities composing the GIAHS often have different priorities, even within the very same GIAHS sites, some municipalities even calling themselves “just a transition point to other destination municipalities.”

Conclusions:
 It is critical for municipal oﬃcers to collaborate with various stakeholders, especially citizens. As such, citizen science is a bottom-up approach to promote biodiversity conservation and facilitate GIAHS managements.
General Wigner Rotations in D Dimensions*
Authors: Chen Fa-Min
Published: May 2019

We construct general Wigner rotations for both massive and massless particles in
D-dimensional spacetime. We work out the explicit expressions of these Wigner rotations for arbitrary Lorentz transformations. We study the relation between the electromagnetic gauge invariance and the non-uniqueness of Wigner rotation.
Extended Phase Space in the Framework of Holography*
Authors: Sherkatghanad Z. , Mirza B. , Nadi H. , Rostami M.
Published: May 2019

We consider a holographic extended phase space in the presence of Reissner-Nordstrom-Anti-de Sitter (RN-AdS) and Born-Infeld-Anti-de Sitter (BI-AdS) black holes in the bulk. In this extended phase space the cosmological constant is investigated as pressure and volume is defined as the codimension one-time slice in the bulk geometry enclosed by the minimal area appearing in the computation of the holographic entanglement entropy. These thermodynamics quantities can serve as probes of the underlying phase transition dictated by black hole thermodynamics, but do not describe different structures. We find that the isocharges on the pressure-volume plane exhibit a Van der Waals-like structure, for RN-AdS black holes in the background. For BI-AdS black holes, we observe the analogy with a Van der Waals liquid-gas system for βQ > 1/2 and Reentrant phase transition for βQ < 1/2 in the holographic extended phase space. The same holographic thermodynamic behavior is observed when we use the fidelity susceptibility as the volume and the cosmological constant as the pressure for RN-AdS black hole in the background.
Behavior of Anisotropic Compact Stars in f(R, ϕ) Gravity*
Authors: Shamir M. Farasat , Malik Adnan
Published: May 2019

The aim of this paper is to investigate modified f(R, ϕ) theory of gravity, where R and ϕ represent the Ricci scalar and scalar potential respectively. Specifically, we take the spherically symmetric spacetime to discuss the possible emergence of compact stars. We study the physical behavior of compact stars by considering 4U 1820-30, SAX J 1808-3658 and Her X1, which are three popular models of compact stars. The graphical analysis of energy density, radial pressure, tangential pressure, energy conditions as well as stability of compact stars has been shown. It is concluded that behavior of these three stars is usual for f(R, ϕ) gravity models with some specific choices of model parameters.
Phase Time for the Tunneling of Ultracold V-Type Atoms Through a Mazer Cavity*
Authors: Badshah Fazal , Basit Abdul , Ali Hamad , He Qing , Ge Guo-Qin
Published: May 2019

We study the tunneling time of ultracold V-type atoms interacting a high quality microwave cavity. Here atomic coherence is introduced in the system by a strong driving field which couples the two lower states of the three-level atom. It is found that in the presence of coherence, mazer action or the scattering like nature of the interaction may be examined for extended energies of the incident cold atoms. Our results show that position and amplitudes of the peak values of the phase time (traversal time) may be very effectively controlled by the coherent driving field. Further, here we obtained superclassical values of the phase time corresponding to much higher values of the transmission amplitudes of the tunneling atoms which may be advantageous in the possible experimental realization of the superclassical tunneling time of the traversing cold atoms. In addition, we examine a mirror reflection type symmetry in the phase time curve for a judicious choice of the external driving field.
Exact Solutions to the Quantum Rabi-Stark Model Within Tunable Coherent States*
Authors: Xie You-Fei , Chen Qing-Hu
Published: May 2019

The quantum Rabi-Stark model, where the linear dipole coupling and the nonlinear Stark-like coupling is present on an equal footing, is studied within the tunable extended coherent states. The eigenvalues and eigenstates are therefore obtained exactly. Surprisingly, the entanglement entropy in the ground-state is found to jump suddenly with the coupling strength. The first-order quantum phase transition can be detected by level crossing of the ground state and the first excited state, which is however lacking in the original linear quantum Rabi model. Performing the first-order approximation in the present theory, we can derive closed-form analytical results for the ground-state. Interestingly, it agrees well with the exact solutions up to the ultra-strong coupling regime in a wide range of model parameters. The spectral collapses when the absolute value of the nonlinear coupling strength approaches to twice the cavity frequency is observed with the help of new solutions in the limits.
Nonlinear saturation and oscillations of collisionless zonal flows
Authors: Zhu Hongxuan , Zhou Yao , Dodin I Y
Published: May 2019

In homogeneous drift-wave turbulence, zonal flows (ZFs) can be generated via a modulational instability (MI) that either saturates monotonically or leads to oscillations of the ZF energy at the nonlinear stage. This dynamics is often attributed as the predator–prey oscillations induced by ZF collisional damping; however, similar dynamics is also observed in collisionless ZFs, in which case a different mechanism must be involved. Here, we propose a semi-analytic theory that explains the transition between the oscillations and saturation of collisionless ZFs within the quasilinear Hasegawa–Mima model. By analyzing phase-space trajectories of DW quanta (driftons) within the geometrical-optics (GO) approximation, we argue that the parameter that controls this transition is N ∼ γ
MI/ω
DW, where γ
MI is the MI growth rate and ω
DW is the linear DW frequency. We argue that at N ≪ 1, ZFs oscillate due to the presence of so-called passing drifton trajectories, and we derive an approximate formula for the ZF amplitude as a function of time in this regime. We also show that at N ≳  1, the passing trajectories vanish and ZFs saturate monotonically, which can be attributed to phase mixing of higher-order sidebands. A modification of N that accounts for effects beyond the GO limit is also proposed. These analytic results are tested against both quasilinear and fully-nonlinear simulations. They also explain the earlier numerical results by Connaughton et al (2010 J. Fluid Mech.
654 207) and Gallagher et al (2012 Phys. Plasmas
19 122115) and offer a different perspective on what the control parameter actually is that determines the transition from the oscillations to saturation of collisionless ZFs.
Second order conformal multi-symplectic method for the damped Korteweg–de Vries equation*
Authors: Guo Feng
Published: May 2019

A conformal multi-symplectic method has been proposed for the damped Korteweg–de Vries (DKdV) equation, which is based on the conformal multi-symplectic structure. By using the Strang-splitting method and the Preissmann box scheme, we obtain a conformal multi-symplectic scheme for multi-symplectic partial differential equations (PDEs) with added dissipation. Applying it to the DKdV equation, we construct a conformal multi-symplectic algorithm for it, which is of second order accuracy in time. Numerical experiments demonstrate that the proposed method not only preserves the dissipation rate of mass exactly with periodic boundary conditions, but also has excellent long-time numerical behavior.
Turing pattern in the fractional Gierer–Meinhardt model*
Authors: Wang Yu , Zhang Rongpei , Wang Zhen , Han Zijian
Published: May 2019

It is well-known that reaction–diffusion systems are used to describe the pattern formation models. In this paper, we will investigate the pattern formation generated by the fractional reaction–diffusion systems. We first explore the mathematical mechanism of the pattern by applying the linear stability analysis for the fractional Gierer–Meinhardt system. Then, an efficient high-precision numerical scheme is used in the numerical simulation. The proposed method is based on an exponential time differencing Runge–Kutta method in temporal direction and a Fourier spectral method in spatial direction. This method has the advantages of high precision, better stability, and less storage. Numerical simulations show that the system control parameters and fractional order exponent have decisive influence on the generation of patterns. Our numerical results verify our theoretical results.
Tensile-strain induced phonon splitting in diamond*
Authors: Pu Meifang , Zhang Feng , Liu Shan , Irifune Tetsuo , Lei Li
Published: May 2019

The first-order Raman spectroscopy of diamond exhibits splitting and redshift after the burst of high-pressure (160–200 GPa) and high-temperature (∼2000 K). The observed longitudinal optical (LO) and the transverse optical (TO) splitting of Raman phonon is related to the tensile-strain induced activation of the forbidden or silent Raman modes that arise in the proximity of the Brillouin zone center.
Dependence of photoelectron-momentum distribution of

H

2

+

molecule on orientation angle and laser ellipticity*
Authors: Zhang Hong-Dan , Zhang Si-Qi , Ji Lei , Zhen Qi , Guo Jing , Liu Xue-Shen
Published: May 2019

By numerically solving the two-dimensional time-dependent Schrödinger equation under the frozen-nuclei approximation, we are able to study the molecular photoelectron-momentum distribution (MPMD) of

H

2

+

with different orientation angles driven by elliptically polarized laser pulse with varying ellipticities. Our numerical results show that the MPMD is sensitive to the orientation angle and the laser ellipticity, which can be explained by the attosecond perturbation ionization theory and the exactly solvable photoionization model. When the ellipticity ε=0, the final MPMD of x-oriented

H

2

+

shows a distinct six-lobe pattern that is different from that with ε=0.5 and ε=1. The evolutions of electron wave packet (EWP) and MPMD with x-oriented

H

2

+

are presented to interpret this distinct pattern.
Dynamics of Airy beams in parity–time symmetric optical lattices
Authors: Chen Rui-Hong , Hong Wei-Yi
Published: May 2019

We investigate the dynamics of airy beams propagating in the parity–time (PT) symmetric optical lattices in linear and nonlinear regimes, respectively. For the linear propagation, the position of the channel guided by the PT lattice can be shifted by tuning the lattice frequency. The underlying physical mechanism of this phenomenon is also discussed. An interesting phenomenon is found in the nonlinear regime in that the airy beam becomes a tilt channel with several Rayleigh lengths. These findings create new opportunities for optical steering and manipulations.
Mid-infrared supercontinuum generation and its application on all-optical quantization with different input pulses*
Authors: Li Yan , Sang Xinzhu
Published: May 2019

Supercontinuum generation (SCG) and its application on all-optical quantization of all-optical analog-to-digital conversions (AOADCs) at the mid-infrared region in an AlGaAs strip waveguide are investigated numerically. The simulation results show that when the parabolic pulse is input, not only broader and higher-coherence SCG is obtained and a higher effective number of bits (ENOB) can be achieved, compared with the input pulse with hyperbolic-secant and Gaussian shaping. A four-bit quantization resolution is achieved along with a signal-to-noise ratio of 24.02 dB and an ENOB of 3.99 bit, and the required input peak power is 760 mW.
An experimental method for quantitative analysis of real contact area based on the total reflection optical principle*
Authors: Luo Zhijun , Song Baojiang , Han Jingyu , Yan Shaoze
Published: May 2019

The simulation of real contact area between materials is foundationally important for the contact mechanics of mechanical structures. The Greenwood and Williamson (GW) model and the Majumdar (MB) model are the basic models in this field, which are widely accepted and proven to be valid in many experiments and engineering. Although the contact models have evolved considerably in recent years, the verifications of the models are most based on the indirect methods such as electrical conductivity and contact stiffness, because of the lack of effective methods to directly measure the variation of contact surface. In this paper, the total reflection (TR) method is introduced into the verification of contact models. An experiment system based on TR method is constructed to measure the real contact area of two PMMA specimens. The comparison analysis between the results of experiment and models suggests that the experiment result has the same trend with simulation, the MB model has better agreement with the experimental result because this method can take into account the variation of radius and the merging of asperities, while the GW model has a huge deviation because of the dependence on resolution and the lack of considering the variation of radius and asperity’s merging process. Taking the interaction of asperities into account could give a better result that is closer to the experiment. Our results and analysis prove that the experimental methods in this paper could be used as a more direct and valid method to quantitatively measure the real contact area and to verify the contact models.
Crystallographic and magnetic properties of van der Waals layered FePS3 crystal*
Authors: Xie Qi-Yun , Wu Min , Chen Li-Min , Bai Gang , Zou Wen-Qin , Wang Wei , He Liang
Published: May 2019

The crystallographic and magnetic properties are presented for van der Waals antiferromagnetic FePS3. High-quality single crystals of millimeter size have been successfully synthesized through the chemical vapor transport method. The layered structure and cleavability of the compound are apparent, which are beneficial for a potential exploration of the interesting low dimensional magnetism, as well as for incorporation of FePS3 into van der Waals heterostructures. For the sake of completeness, we have measured both direct current (dc) and alternating current (ac) magnetic susceptibility. The paramagnetic to antiferromagnetic transition occurs at approximately

T

N

∼
115

K

. The effective moment is larger than the spin-only effective moment, suggesting that an orbital contribution to the total angular momentum of the Fe2+ could be present. The ac susceptibility is independent of frequency, which means that the spin freezing effect is excluded. Strong anisotropy of out-of-plane and in-plane susceptibility has been shown, demonstrating the Ising-type magnetic order in FePS3 system.
Raman scattering study of magnetic layered MPS3 crystals (

M
=
Mn

, Fe, Ni)*
Authors: Wang Yi-Meng , Zhang Jian-Feng , Li Cheng-He , Ma Xiao-Li , Ji Jian-Ting , Jin Feng , Lei He-Chang , Liu Kai , Zhang Wei-Lu , Zhang Qing-Ming
Published: May 2019

We report a comprehensive Raman scattering study on layered MPS3 (M=Mn, Fe, Ni), a two-dimensional magnetic compound with weak van der Waals interlayer coupling. The observed Raman phonon modes have been well assigned by the combination of first-principles calculations and the polarization-resolved spectra. Careful symmetry analysis on the angle-dependent spectra demonstrates that the crystal symmetry is strictly described by C2h but can be simplified to D3d with good accuracy. Interestingly, the three compounds share exactly the same lattice structure but show distinct magnetic structures. This provides us with a unique opportunity to study the effect of different magnetic orders on lattice dynamics in MPS3. Our results reveal that the in-plane Néel antiferromagnetic (AF) order in MnPS3 favors a spin–phonon coupling compared to the in-plane zig-zag AF in NiPS3 and FePS3. We have discussed the mechanism in terms of the folding of magnetic Brillouin zones. Our results provide insights into the relation between lattice dynamics and magnetism in the layered MPX
3 (M=transition metal, X=S, Se) family and shed light on the magnetism of monolayer MPX
3 materials.
Conductive property of Zr0.1Fe0.9V1.1Mo0.9O7 with low thermal expansion*
Authors: He Xiaoke , Qi Heng , Xu Qi , Liu Xiansheng , Xu Lei , Yuan Baohe
Published: May 2019

Low thermal expansion materials are mostly ceramics with low conductive property, which limits their applications in electronic devices. The poor conductive property of ceramic ZrV2O7 could be improved by bi-substitution of Fe and Mo for Zr and V, accompanied with low thermal expansion. Zr0.1Fe0.9V1.1Mo0.9O7 has electrical conductivity of 8.2×10−5 S/cm and 9.41×10−4 S/cm at 291 K and 623 K, respectively. From 291 K to 413 K, thermal excitation leads to the increase of carrier concentration, which causes the rapid decrease of resistance. At 413–533 K, the conductivity is unchanged due to high scattering probability and a slowing increase of carrier concentration. The conductivity rapidly increases again from 533 K to 623 K due to the intrinsic thermal excitation. The thermal expansion coefficient of Zr0.1Fe0.9V1.1Mo0.9O7 is as low as 0.72×10−6 K−1 at 140–700 K from the dilatometer measurement. These properties suggest that Zr0.1Fe0.9V1.1Mo0.9O7 has attractive application in electronic components.
Mott transition in ruby lattice Hubbard model*
Authors: Bao An
Published: May 2019

Mott transition in a ruby lattice with fermions described by the Hubbard model including on-site repulsive interaction is investigated by combining the cellular dynamical mean-field theory and the continuous-time quantum Monte Carlo algorithm. The effect of temperature and on-site repulsive interaction on the metallic–insulating phase transition in ruby lattice with fermions is discussed based on the density of states and double occupancy. In addition, the magnetic property of each phase is discussed by defining certain magnetic order parameters. Our results show that the antiferromagnetic metal is found at the low temperature and weak interaction region and the antiferromagnetic insulating phase is found at the low temperature and strong interaction region. The paramagnetic metal appears in whole on-site repulsive interaction region when the temperature is higher than a certain value and the paramagnetic insulator appears at the middle scale of temperature and on-site repulsive interaction.
Magnetic properties and magnetocaloric effects in (Ho1−xYx)5Pd2 compounds*
Authors: Wu X F , Guo C P , Cheng G , Li C R , Wang J , Du Y S , Rao G H , Du Z M
Published: May 2019

The crystal structure, magnetic and magnetocaloric properties of (Ho1−x
Y
x
)5Pd2 (x = 0, 0.25, and 0.5) compounds are investigated. All the compounds crystallize in a cubic Dy5Pd2-type structure with the space group Fd3m and undergo a second order transition from spin glass (SG) state to paramagnetic (PM) state. The spin glass transition temperatures T
g decrease from 26 K for x = 0 to 13 K for x = 0.5. In the PM region, the reciprocal susceptibilities for all the compounds obey the Curie–Weiss law. The paramagnetic Curie temperatures (

θ

p

) for Ho5Pd2, (Ho0.75Y0.25)5Pd2, and (Ho0.5Y0.5)5Pd2 are determined to be 32 K, 30 K, and 22 K, respectively, and the corresponding effective magnetic moments (

μ

eff

)

are 10.8

μ

B

/Ho, 10.3

μ

B

/RE, and 7.5

μ

B

/RE, respectively. Magnetocaloric effect (MCE) is anticipated according to the Maxwell relation, based on the isothermal magnetization curves. For a magnetic field change of 0–5 T, the maximum values of the isothermal magnetic entropy change

−
Δ

S

M

of the (Ho1−x
Y
x
)5Pd2 (x = 0, 0.25, and 0.5) compounds are determined to be

11.5

J
·

kg

−
1

·

K

−
1

,

11.1

J
·

kg

−
1

·

K

−
1

, and

8.9

K

J
·

kg

−
1

·

K

−
1

, with corresponding refrigerant capacity values of

382.3

J
·

kg

−
1

,

336.2

J
·

kg

−
1

, and

242.5

J
·

kg

−
1

, respectively.
Computational study of inverse ferrite spinels
Authors: Maazouzi A EL , Masrour R , Jabar A , Hamedoun M
Published: May 2019

The magnetic properties of inverse ferrite

(

Fe

3
+

)
[

Fe

3
+

Co

2
+

]

O

4

2
−

,
(

Fe

3
+

)
[

Fe

3
+

Cu

2
+

]

O

4

2
−

,
(

Fe

3
+

)
[

Fe

3
+

Fe

2
+

]

O

4

2
−

, and

(

Fe

3
+

)
[

Fe

3
+

Ni

2
+

]

O

4

2
−

spinels have been studied using Monte Carlo simulation. We have also calculated the critical and Curie Weiss temperatures from the thermal magnetizations and inverse of magnetic susceptibilities for each system. Magnetic hysteresis cycles have been found for the four systems. Finally, we found the critical exponents associated with magnetization, magnetic susceptibility, and external magnetic field. Our results of critical and Curie Weiss temperatures are similar to those obtained by experiment results. The critical exponents are similar to those of known 3D-Ising model.
Responsivity and noise characteristics of AlGaN/GaN-HEMT terahertz detectors at elevated temperatures*
Authors: Tian Zhi-Feng , Xu Peng , Yu Yao , Sun Jian-Dong , Feng Wei , Ding Qing-Feng , Meng Zhan-Wei , Li Xiang , Cai Jin-Hua , Zheng Zhong-Xin , Li Xin-Xing , Jin Lin , Qin Hua , Sun Yun-Fei
Published: May 2019

The responsivity and the noise of a detector determine the sensitivity. Thermal energy usually affects both the responsivity and the noise spectral density. In this work, the noise characteristics and responsivity of an antenna-coupled AlGaN/GaN high-electron-mobility-transistor (HEMT) terahertz detector are evaluated at temperatures elevated from 300 K to 473 K. Noise spectrum measurement and a simultaneous measurement of the source–drain conductance and the terahertz photocurrent allow for detailed analysis of the electrical characteristics, the photoresponse, and the noise behavior. The responsivity is reduced from 59 mA/W to 11 mA/W by increasing the detector temperature from 300 K to 473 K. However, the noise spectral density maintains rather constantly around 1–2 pA/Hz1/2 at temperatures below 448 K, above which the noise spectrum abruptly shifts from Johnson-noise type into flicker-noise type and the noise density is increased up to one order of magnitude. The noise-equivalent power (NEP) is increased from 22 pW/Hz1/2 at 300 K to 60 pW/Hz1/2 at 448 K mainly due to the reduction in mobility. Above 448 K, the NEP is increased up to 1000 pW/Hz1/2 due to the strongly enhanced noise. The sensitivity can be recovered by cooling the detector back to room temperature.