bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-organized environment-sensitive inulin–doxorubicin conjugate with a selective cytotoxic effect towards cancer cells
Authors: Mauro N. , Campora S. , Scialabba C. , Adamo G. , Licciardi M. , Ghersi G. , Giammona G.
Published: April 2015

An inulin-based copolymer bearing high dose doxorubicin (18.45 % w/w), INU-EDA-P,C-DOXO, was prepared by coupling doxorubicin with inulin though citraconylamide bridge used as pH sensitive spacer. Its smart and selective anticancer effect was proved.
Catalytic polymer reactor with “self-sorting” domains for hierarchical catalysis
Authors: Li Qin , Zhu Maiyong , Shen Xiaojuan , Li Songjun
Published: April 2015

Hierarchical catalysis was realized by using a polymer reactor containing self-sorting domains, which acted as a switch for providing sequenced access to the encapsulated metal nanoparticles.
SnS2 nanotubes: a promising candidate for the anode material for lithium ion batteries
Authors: Huang Yucheng , Ling Chongyi , Chen Xi , Zhou Danmei , Wang Sufan
Published: April 2015

The adsorption and diffusion of Li on SnS2 nanotubes.
High performance alumina based graphene nanocomposites with novel electrical and dielectric properties
Authors: Ahmad Kaleem , Pan Wei , Wu Hui
Published: April 2015

Thermally reduced graphene nanosheets in alumina demonstrate novel electrical and dielectric properties of the composites.
Highly transparent porous ZrO2 thin films: fabrication and optical properties
Authors: Chen Yu , Li Aolin , Li Yige , Li Junfei , Dai Guozhang , Fangping Ouyang , Xiong Xiang
Published: April 2015

Porous ZrO2 thin films that are highly transparent to visible and infrared light were fabricated via a simple sol–gel dip-coating method, and have promising potential applications in solar cells as a high-temperature-resistant insulating layer.
Extraction and GC-MS analysis of phthalate esters in food matrices: a review
Authors: Russo Mario Vincenzo , Avino Pasquale , Perugini Luisa , Notardonato Ivan
Published: April 2015

According to the Scopus database, using “phthalate” and “GC” as keywords, 758 papers have been found between 1990 and 2014, showing strong and increasing interest in this class of compounds from the scientific community.
Pd nanoparticles supported on nitrogen, sulfur-doped three-dimensional hierarchical nanostructures as peroxidase-like catalysts for colorimetric detection of xanthine
Authors: Shi Weijie , Fan Hai , Ai Shiyun , Zhu Lusheng
Published: April 2015

Pd nanoparticles supported on N, S-doped three-dimensional hierarchical nanostructure acts as novel peroxidase mimic for sensitive detection of xanthine.
Insights into the hydrogenation mechanism of nitrobenzene to aniline on Pd3/Pt(111): a density functional theory study
Authors: Zhang Lianyang , Jiang Junhui , Shi Wei , Xia Shengjie , Ni Zheming , Xiao Xuechun
Published: April 2015

The hydrogenation mechanism of nitrobenzene to aniline on Pd3/Pt(111) surface preferentially follows the direct route and fits best the Jackson reaction mechanism (mechanism B).
Microwave-assisted optimization of the manganese redox states for enhanced capacity and capacity retention of LiAlxMn2−xO4 (x = 0 and 0.3) spinel materials
Authors: Nkosi Funeka P. , Jafta Charl J. , Kebede Mesfin , le Roux Lukas , Mathe Mkhulu K. , Ozoemena Kenneth I.
Published: April 2015

Microwave can shrink particle size and lattice parameters for improved crystallinity, and tune the manganese average valence for enhanced electrochemistry.
Development of environmentally sensitive fluorescent and dual emissive deoxyuridine analogues
Authors: Barthes N. P. F. , Karpenko J. , Dziuba D. , Spadafora M. , Auffret J. , Demchenko A. P. , Mély Y. , Benhida R. , Michel B. Y. , Burger A.
Published: April 2015

We designed and developed fluorescent deoxyuridine analogues with strong sensitivity to hydration for the major groove labelling of DNA.
Intermolecular interaction and mechanical properties of energetic plasticizer MN reinforced 2,4,6-trinitrotoluene/1,3,5-trinitrohexahydro-1,3,5-triazine molten-energetic-composite (MEC)
Authors: Ma Qing , Wen Maoping , Zheng Baohui , He Chuanlan , Huang Hengjian , Liu Dabin
Published: April 2015

An energetic plasticizer MN reinforced MEC with superior mechanical performance was fabricated and the reinforcement mechanism was investigated by microscopy and the QC/MD method.
Platinum(ii) polymetallayne-based phosphorescent polymers with enhanced triplet energy-transfer: synthesis, photophysical, electrochemistry, and electrophosphorescent investigation
Authors: Huang Zuan , Liu Boao , Zhao Jiang , He Yue , Yan Xiaogang , Xu Xianbin , Zhou Guijiang , Yang Xiaolong , Wu Zhaoxin
Published: April 2015

Promoting triplet energy-transfer in novel phosphorescent polymers with platinum(ii) polymetallayne backbones to achieve high EL performances with ηL of 11.49 cd A−1, ηext of 4.38% and ηP of 3.78 lm W−1.
Photonic design of embedded dielectric scatterers for dye sensitized solar cells
Authors: Byranvand Mahdi Malekshahi , Dabirian Ali , Kharat Ali Nemati , Taghavinia Nima
Published: April 2015

A photonic design approach is proposed to determine the optimal size and concentration of dielectric scatterers for nanostructured solar cells.
Role of multiwalled carbon nanotubes (MWCNTs) on rheological, thermal and electrical properties of PC/ABS blend
Authors: Rostami Amir , Masoomi Mohsen , Fayazi Mohammad Javad , Vahdati Mehdi
Published: April 2015

Investigation of MWCNTs localization and its impact on rheological, electrical, and thermal properties of PC/ABS(75/25)/MWCNTs blend nanocomposites.
Dielectric and thermal behaviors of POSS reinforced polyurethane based polybenzoxazine nanocomposites
Authors: Sasi kumar R. , Alagar M.
Published: April 2015

The preparation of POSS reinforced polyurethane based polybenzoxazine nanocomposites as an interlayer low k dielectrics.
Metal-free regioselective C-3 nitration of quinoline N-oxides with tert-butyl nitrite
Authors: Zhao Jingjing , Li Pan , Xia Chungu , Li Fuwei
Published: April 2015

A direct, regioselective and eco-friendly C3-nitration of quinolineN-oxides usingtert-butyl nitrite as both the nitro source and oxidant has been developed. This reaction undergoes a free radical process and can be smoothly scaled up to gram scale.
A divergent route to core- and peripherally functionalized diazacoronenes that act as colorimetric and fluorescence proton sensors
Authors: He Bo , Dai Jing , Zherebetskyy Danylo , Chen Teresa L. , Zhang Benjamin A. , Teat Simon J. , Zhang Qichun , Wang Linwang , Liu Yi
Published: April 2015

One-stop center for functional polycyclic aromatic hydrocarbons — a dichlorodiazaperylene intermediate has been synthesized and employed for the synthesis of highly functionalized coronene derivatives.
Is a polymer semiconductor having a “perfect” regular structure desirable for organic thin film transistors?
Authors: Hong Wei , Chen Shaoyun , Sun Bin , Arnould Mark A. , Meng Yuezhong , Li Yuning
Published: April 2015

Appreciable amounts of structural defects produced during Stille coupling polymerization have unexpected beneficial effects on the molecular ordering and charge transport performance of polymers.
Stimuli-responsive Pickering emulsions: recent advances and potential applications
Authors: Tang Juntao , Quinlan Patrick James , Tam Kam Chiu
Published: April 2015

Pickering emulsions with stimuli-responsive properties have, in recent years, received a considerable amount of attention. This paper provides a concise and comprehensive review of Pickering emulsion systems that possess the ability to respond to an array of external triggers, including pH, temperature, CO2concentration, light intensity, ionic strength, and magnetic field intensity.
Facile scalable synthesis and superior lithium storage performance of ball-milled MoS2–graphite nanocomposites
Authors: Zhao Haihua , Zeng Hong , Wu Ying , Zhang Shengen , Li Bo , Huang Yunhui
Published: April 2015

A facile high-energy ball-milling method is developed to synthesize MoS2–graphite (MoS2–C) nanocomposites, which can be used for scalable industrial mass production.
Prediction of high thermoelectric potential in AMN2 layered nitrides: electronic structure, phonons, and anharmonic effects
Authors: Al Rahal Al Orabi Rabih , Orisakwe Esther , Wee Daehyun , Fontaine Bruno , Gautier Régis , Halet Jean-François , Fornari Marco
Published: April 2015

Band structures, electronic transport coefficients, harmonic and anharmonic vibrational properties of novel layered nitrides have been studied to evaluate the potential for thermoelectric applications.
Cubic C96: a novel carbon allotrope with a porous nanocube network
Authors: Li Da , Tian Fubo , Chu Binhua , Duan Defang , Wei Shuli , Lv Yunzhou , Zhang Huadi , Wang Lu , Lu Nan , Liu Bingbing , Cui Tian
Published: April 2015

A novel carbon allotrope C96 with a low density and porous nanocube network has been predicted.
Solid oxide cells with zirconia/ceria Bi-Layer electrolytes fabricated by reduced temperature firing
Authors: Gao Zhan , Zenou Victor Y. , Kennouche David , Marks Laurence , Barnett Scott A.
Published: April 2015

Solid oxide cells with thin bi-layer YSZ/GDC electrolytes, with excellent performance and stability, were prepared by a reduced-temperature (1250 °C) co-firing process enabled by the addition of a Fe2O3 sintering aid.
Preparation of ALG-g-Lys and its application as a novel drug carrier
Authors: Liu Yuangang , Chen Zongxiang , Wang Shibin , Long Ruimin , Fan Jingqian , Chen Aizheng , Wu Wenguo
Published: April 2015

In order to improve alginate microbead stability and further broaden the application of alginate in biomaterials, a new biomaterial, ALG-g-Lys, was prepared and its possibility as a novel drug carrier investigated.
Tailored upconversion emission of Eu3+in Sr2Ca(W,Mo)O6:Yb3+,Eu3+by a laser via an electronic polarization mechanism
Authors: Li Ye , Liu Tianhui , Ye Shi , Deng Tengfei , Yi Xiong , Zhang Qinyuan , Jing Xiping
Published: April 2015

The5D0→7F4upconversion emission of Eu3+in Sr2Ca(W,Mo)O6:Yb3+,Eu3+is tailored by a laserviaan electronic polarization mechanism, which is deduced by AC impedance spectroscopy measurements and theoretical calculations of the dielectric function.
Hepcidin: regulation of the master iron regulator
Authors: Rishi Gautam , Wallace Daniel F. , Subramaniam V. Nathan
Published: April 2015

Iron, an essential nutrient, is required for many diverse biological processes. The absence of a defined pathway to excrete excess iron makes it essential for the body to regulate the amount of iron absorbed; a deficiency could lead to iron deficiency and an excess to iron overload and associated disorders such as anaemia and haemochromatosis respectively. This regulation is mediated by the iron-regulatory hormone hepcidin. Hepcidin binds to the only known iron export protein, ferroportin (FPN), inducing its internalization and degradation, thus limiting the amount of iron released into the blood. The major factors that are implicated in hepcidin regulation include iron stores, hypoxia, inflammation and erythropoiesis. The present review summarizes our present knowledge about the molecular mechanisms and signalling pathways contributing to hepcidin regulation by these factors.
Looking to the horizon: the role of bilirubin in the development and prevention of age-related chronic diseases
Authors: Wagner Karl-Heinz , Wallner Marlies , Mölzer Christine , Gazzin Silvia , Bulmer Andrew Cameron , Tiribelli Claudio , Vitek Libor
Published: April 2015

Bilirubin, the principal tetrapyrrole, bile pigment and catabolite of haem, is an emerging biomarker of disease resistance, which may be related to several recently documented biological functions. Initially believed to be toxic in infants, the perception of bilirubin has undergone a transformation: it is now considered to be a molecule that may promote health in adults. Data from the last decade demonstrate that mildly elevated serum bilirubin levels are strongly associated with reduced prevalence of chronic diseases, particularly cardiovascular diseases (CVDs), as well as CVD-related mortality and risk factors. Recent data also link bilirubin to other chronic diseases, including cancer and Type 2 diabetes mellitus, and to all-cause mortality. Therefore, there is evidence to suggest that bilirubin is a biomarker for reduced chronic disease prevalence and a predictor of all-cause mortality, which is of important clinical significance. In the present review, detailed information on the association between bilirubin and all-cause mortality, as well as the pathological conditions of CVD, cancer, diabetes and neurodegenerative diseases, is provided. The mechanistic background concerning how bilirubin and its metabolism may influence disease prevention and its clinical relevance is also discussed. Given that the search for novel biomarkers of these diseases, as well as for novel therapeutic modalities, is a key research objective for the near future, bilirubin represents a promising candidate, meeting the criteria of a biomarker, and should be considered more carefully in clinical practice as a molecule that might provide insights into disease resistance. Clearly, however, greater molecular insight is warranted to support and strengthen the conclusion that bilirubin can prevent disease, with future research directions also proposed.
Effects of normoxic and hypoxic exercise regimens on monocyte-mediated thrombin generation in sedentary men
Authors: Wang Jong-Shyan , Chang Ya-Lun , Chen Yi-Ching , Tsai Hsing-Hua , Fu Tieh-Cheng
Published: April 2015

Exercise and hypoxia paradoxically modulate vascular thrombotic risks. The shedding of procoagulant-rich microparticles from monocytes may accelerate the pathogenesis of atherothrombosis. The present study explores the manner in which normoxic and hypoxic exercise regimens affect procoagulant monocyte-derived microparticle (MDMP) formation and monocyte-promoted thrombin generation (TG). Forty sedentary healthy males were randomized to perform either normoxic (NET; 21% O2, n=20) or hypoxic (HET; 15% O2, n=20) exercise training (60% VO2max) for 30 min/day, 5 days/week for 5 weeks. At rest and immediately after HET (100 W under 12% O2 for 30 min), the MDMP characteristics and dynamic TG were measured by flow cytometry and thrombinography respectively. The results demonstrated that acute 12% O2 exercise (i) increased the release of coagulant factor V (FV)/FVIII-rich, phosphatidylserine (PS)-exposed and tissue factor (TF)-expressed microparticles from monocytes, (ii) enhanced the peak height and rate of TG in monocyte-rich plasma (MRP) and (iii) elevated concentrations of norepinephrine/epinephrine, myeloperoxidase (MPO) and interleukin-6 (IL-6) in plasma. Following the 5-week intervention, HET exhibited higher enhancements of peak work-rate and cardiopulmonary fitness than NET did. Moreover, both NET and HET decreased the FV/FVIII-rich, PS-exposed and TF-expressed MDMP counts and the peak height and rate of TG in MRP following the HET. However, HET elicited more suppression for the HE (hypoxic exercise)-enhanced procoagulant MDMP formation and dynamic TG in MPR and catecholamine/peroxide/pro-inflammatory cytokine levels in plasma than NET. Hence, we conclude that HET is superior to NET for enhancing aerobic capacity. Furthermore, HET effectively suppresses procoagulant MDMP formation and monocyte-mediated TG under severe hypoxic stress, compared with NET.
Controller dynamic linearisation‐based model‐free adaptive control framework for a class of non‐linear system
Authors: Zhu Yuanming , Hou Zhongsheng
Published: April 2015

Without the explicit process identification, the authors propose a model‐free adaptive control framework for unknown plant by using the concept of equivalent dynamic linearisation controller. The controller has linear incremental structure and its local dynamics is equivalent to the ideal controller in theory. Hence, the problem of determining the structure of candidate controller is transformed to the problem of finding a sequence of local dynamic controllers to approximate the ideal controller. With the help of gradient information extracted from input and output (I/O) data of the plant, the optimal controller parameter sequence is generated by minimising a user‐defined control criterion. This method gives a solution on how to determine the candidate controller structure. The controller design, parameter tuning and controller validation are based on I/O data of the plant. Hence, it could reduce the influence of internal disturbance or unmodelled dynamics. The effectiveness of the proposed method is illustrated by the simulation of a continuous polymerisation reaction process in a jacketed continuous stirred tank reactor system. Meanwhile, a simulation comparison is carried out to show the superiority of neural network data model in model‐free adaptive control framework.
Security analysis of a three‐dimensional rotation‐based image encryption
Authors: Nini Brahim , Lemmouchi Chahra
Published: April 2015

This study presents an analysis of the basis of a new method presented recently in the image encryption domain. The method might use different schemes of bits projection where the rotation about some axes is the basic part. This work is an analysis of the effect of each angle of a three‐dimensional (3D) rotation on the quality of encryption. Moreover, in order to neglect any type of projection that may influence the quality of the results, the simplest form of projection is used; that is, after the 3D rotation of a point, it is simply projected on the plane (xy). Even though no diffusion is applied in the currently presented algorithm, the results are very promising.
Classes of reconfigurable band‐reject filters realising constant absolute bandwidth in two distinct states
Authors: Fathelbab Wael M.
Published: April 2015

This study presents the synthesis and design of novel band‐reject filters whose frequency characteristics can be reconfigured between two distinct states, each of which is centred at a different resonant frequency. The absolute bandwidth of the reconfigurable filters in the two distinct states is maintained constant by virtue of introducing two new resonator types which are thoroughly studied and analysed in this work. The synthesis of two prototype networks realising a common electrical specification is illustrated and each network is subsequently transformed into two types of band‐reject filters comprising novel coupled‐line sections. The presented circuit concepts are then validated through the simulation of a suspended‐substrate stripline filter modelled utilising high frequency structure simulator (HFSS) which realises an absolute bandwidth of 200 MHz in the two distinct states centred at 1180 and 1485 MHz. The HFSS filter model is manually reconfigured between the two distinct states upon terminating stubs within each of its resonator structures as either open circuit or short circuit. The performance of the HFSS filter model shows close correspondence to the performance of the synthesised prototype network, thus demonstrating the validity of the proposed circuit principles.
Current‐tripler‐rectifier pulse width modulation ZVS three‐phase full‐bridge DC/DC converter with Y–Δ connected transformer
Authors: Gu Ling , Jin Ke , Liu Chang
Published: April 2015

To decrease the current stress of the switches in high power applications, a current‐tripler‐rectifier zero voltage switching (ZVS) three‐phase full‐bridge DC/DC converter with pulse width modulation (PWM) control strategy is proposed in this study. The converter utilises a three‐phase full‐bridge structure at the primary side and a current‐tripler rectifier at the secondary side. The converter applies to situations involving high power, high input voltage and large output current. The three‐phase interleaved structure not only decreases the current stress of the switches, but also increases the frequency of input and output current ripple to three times as large as the switching frequency, which reduces the filter inductance. All switches achieve ZVS with the proper PWM control strategy. It is quite easy to achieve ZVS for lower switches of the bridge leg since the energy coming from the output filter inductor discharges the junction capacitors. Since the energy of upper switches achieving ZVS comes from the leakage inductors of two phase transformers, it is easier to achieve ZVS for upper switches of this converter than lagging‐leg switches of the phase‐shifted full‐bridge converter. A prototype with 360 V input and 48/42 A output was built in the lab and experimental results verified the theoretical analysis.
Radial force dynamic current compensation method of single winding bearingless flywheel motor
Authors: Yuan Ye , Sun Yukun , Huang Yonghong
Published: April 2015

The position of rotor and stator in switched reluctance motor is exchanged to obtain the single winding bearingless flywheel motor (SWBFM), which is more useful for flywheel energy storage with outer rotor. Compared with the switched reluctance motor, bearingless flywheel motor has obvious advantages in cost savings and consumption reducing. The radial force and torque are produced by single windings and the outer rotor could directly drive the flywheel with less mechanical transmission. In this study, a mathematical model of SWBFM is established based on Maxwell tensor method, in addition, the correction factor is present to obtain an accurate mathematical model based on finite element. In energy storage keeping state, the flywheel energy storage system could run on rated speed without the power input. Considering the relationship between the angle and the radial force coefficient, and the difference of radial force coefficient with each tooth pole, radial force dynamic current compensation methods of without β direction constraint and β direction constraint are present to ensure the SWBFM stable suspension under the condition of winding open‐circuit fault. The results show that the proposed compensation methods are feasible and have high precision.
Observation of two polytypes of MoS2 ultrathin layers studied by second harmonic generation microscopy and photoluminescence
Authors: Mishina E. , Sherstyuk N. , Lavrov S. , Sigov A. , Mitioglu A. , Anghel S. , Kulyuk L.
Published: April 2015

Second harmonic generation (SHG) of a high intensity was found in MoS2 flakes of different thicknesses exfoliated on a silicon substrate. Reduction of the SHG intensity was observed only for a small portion of flakes, for both very thin and quite thick ones. This was attributed to the presence of polytypism, i.e., of 3R non-centrosymmetric and 2H centrosymmetric polytypes, in a source bulk crystal grown by the chemical vapor transport technique. The presence of two polytypes in the sample was confirmed by the spectral structure of the photoluminescence of bound excitons observed in flakes at low temperature. Absolute values of nonlinear susceptibility of MoS2 flakes of different thicknesses were estimated.
Measuring political polarization: Twitter shows the two sides of Venezuela
Authors: Morales A. J. , Borondo J. , Losada J. C. , Benito R. M.
Published: April 2015

We say that a population is perfectly polarized when divided in two groups of the same size and opposite opinions. In this paper, we propose a methodology to study and measure the emergence of polarization from social interactions. We begin by proposing a model to estimate opinions in which a minority of influential individuals propagate their opinions through a social network. The result of the model is an opinion probability density function. Next, we propose an index to quantify the extent to which the resulting distribution is polarized. Finally, we apply the proposed methodology to a Twitter conversation about the late Venezuelan president, Hugo Chávez, finding a good agreement between our results and offline data. Hence, we show that our methodology can detect different degrees of polarization, depending on the structure of the network.
A high-temperaturein situcell with a large solid angle for fluorescence X-ray absorption fine structure measurement
Authors: Murata Naoyoshi , Kobayashi Makoto , Okada Yukari , Suzuki Takuya , Nitani Hiroaki , Niwa Yasuhiro , Abe Hitoshi , Wada Takahiro , Mukai Shingo , Uehara Hiromitsu , Ariga Hiroko , Takakusagi Satoru , Asakura Kiyotaka
Published: April 2015

We present the design and performance of a high-temperature in situ cell with a large solid angle for fluorescence X-ray absorption fine structure (XAFS) spectra. The cell has a large fluorescence XAFS window (116 mmϕ) near the sample in the cell, realizing a large half-cone angle of 56°. We use a small heater (25 × 35 mm2) to heat the sample locally to 873 K. We measured a Pt–SnO2 thin layer on a Si substrate at reaction conditions having a high activity. In situ measurement enables the analysis of the difference XAFS spectra between before and during the reaction to reveal the structure change during the operation.
Dynamic generation of Ince-Gaussian modes with a digital micromirror device
Authors: Ren Yu-Xuan , Fang Zhao-Xiang , Gong Lei , Huang Kun , Chen Yue , Lu Rong-De
Published: April 2015

Ince-Gaussian (IG) beam with elliptical profile, as a connection between Hermite-Gaussian (HG) and Laguerre-Gaussian (LG) beams, has showed unique advantages in some applications such as quantum entanglement and optical micromanipulation. However, its dynamic generation with high switching frequency is still challenging. Here, we experimentally reported the quick generation of Ince-Gaussian beam by using a digital micro-mirror device (DMD), which has the highest switching frequency of 5.2 kHz in principle. The configurable properties of DMD allow us to observe the quasi-smooth variation from LG (with ellipticity ε=0) to IG and HG (ε=∞) beam. This approach might pave a path to high-speed quantum communication in terms of IG beam. Additionally, the characterized axial plane intensity distribution exhibits a 3D mould potentially being employed for optical micromanipulation.
Thermal transport properties of halide solid solutions: Experiments vs equilibrium molecular dynamics
Authors: Gheribi Aïmen E. , Salanne Mathieu , Chartrand Patrice
Published: April 2015

The composition dependence of thermal transport properties of the (Na,K)Cl rocksalt solid solution is investigated through equilibrium molecular dynamics (EMD) simulations in the entire range of composition and the results are compared with experiments published in recent work [Gheribi et al., J. Chem. phys. 141, 104508 (2014)]. The thermal diffusivity of the (Na,K)Cl solid solution has been measured from 473 K to 823 K using the laser flash technique, and the thermal conductivity was deduced from critically assessed data of heat capacity and density. The thermal conductivity was also predicted at 900 K in the entire range of composition by a series of EMD simulations in both NPT and NVT statistical ensembles using the Green-Kubo theory. The aim of the present paper is to provide an objective analysis of the capability of EMD simulations in predicting the composition dependence of the thermal transport properties of halide solid solutions. According to the Klemens-Callaway [P. G. Klemens, Phys. Rev. 119, 507 (1960) and J. Callaway and H. C. von Bayer, Phys. Rev. 120, 1149 (1960)] theory, the thermal conductivity degradation of the solid solution is explained by mass and strain field fluctuations upon the phonon scattering cross section. A rigorous analysis of the consistency between the theoretical approach and the EMD simulations is discussed in detail.
The ionic states of iodobenzene studied by photoionization and ab initio configuration interaction and DFT computations
Authors: Palmer Michael H. , Ridley Trevor , Hoffmann Søren Vrønning , Jones Nykola C. , Coreno Marcello , de Simone Monica , Grazioli Cesare , Biczysko Malgorzata , Baiardi Alberto
Published: April 2015

New valence electron photoelectron spectra of iodobenzene obtained using synchrotron radiation have been recorded. Ionization energies (IEs) determined using multi-configuration SCF calculation (MCSCF) procedures confirmed the adiabatic IE order as: X2B1<A2A2<B2B2<C2B1. Although it is convenient to retain C2v labelling, there is an evidence that minor distortion to CS symmetry occurs at the MCSCF level for the C state. The fifth ionization process shown to be D2A1 exhibits dissociation to C6H5+ + I both in the experimental and theoretical studies. The calculated Franck-Condon vibrational spectral envelopes, including hot band contributions, for the first four ionic states reproduce the observed peak positions and intensities with reasonable accuracy. In order to simulate the observed spectra, different bandwidths are required for different states. The increase in the required bandwidths for the A2A2 and B2B2 states is attributed to internal conversion to lower-lying states. The presence of relatively high intensity sequence bands leads to asymmetry of each of the X2B1 state bands.
The existence result for a relativistic nonlinear Schrödinger equation
Authors: Cheng Yongkuan , Yang Jun
Published: April 2015

We study the existence of positive solutions for a class of quasilinear elliptic equation. This model has been proposed in the self-channeling of a high-power ultra short laser in matter.
Uniqueness of topological multi-vortex solutions for a skew-symmetric Chern-Simons system
Authors: Huang Hsin-Yuan , Lee Youngae , Lin Chang-Shou
Published: April 2015

In this paper, we consider a skew-symmetric Chern-Simons system problem with a coupling parameter. Our main goal is that, when the coupling parameter is small, the topological type solutions to this system problem are uniquely determined by the location of their vortex points. This result follows by the bubbling analysis and the non-degeneracy of linearized equations.
Effect of microstructure on spontaneous polarization in amorphous solid water films
Authors: Bu Caixia , Shi Jianming , Raut Ujjwal , Mitchell Emily H. , Baragiola Raúl A.
Published: April 2015

Amorphous solid water (ASW) films grown by vapor deposition below 110 K develop negative surface voltages Vs with respect to the substrate. This polarization is due to a partial alignment of the water molecules during condensation. Kelvin probe measurements show that the magnitude of the surface potential, |Vs|, increases linearly with film thickness at a rate that decreases with increasing deposition temperature. |Vs| decreases with increasing deposition temperature and increasing incidence angle of the vapor source. After film growth, |Vs| decreases irreversibly by 80% when the ice film is heated to ∼30 K above the deposition temperature. The measurements of |Vs| as a function of film porosity indicate that polarization in ASW is governed by incompletely coordinated water molecules, dangling with unbalanced dipoles at the internal surface of the pores and weakly aligned by the anisotropic film-vacuum interface. This idea is supported by the strikingly similar behavior of |Vs| and the infrared absorption due to the most pliable, two-coordinated surface molecules with annealing temperature.
Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence
Authors: Muthukumaran C. K. , Vaidyanathan Aravind
Published: April 2015

The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.
Theoretical and experimental investigations of the thermoelectric properties of Bi2S3
Authors: Chmielowski Radoslaw , Péré Daniel , Bera Chandan , Opahle Ingo , Xie Wenjie , Jacob Stéphane , Capet Frédéric , Roussel Pascal , Weidenkaff Anke , Madsen Georg K. H. , Dennler Gilles
Published: April 2015

Electronic and transport properties of Bi2S3 with various dopants are studied using density functional theory and experimental characterizations. First, principle calculations of thermoelectric properties are used to evaluate the thermoelectric potential of the orthorhombic Bi2S3 structure. The computational screening of extrinsic defects is used to select the most favorable n-type dopants. Among all the dopants considered, hafnium and chlorine are identified as prospective dopants, whereas, e.g., germanium is found to be unfavorable. This is confirmed by experiment. Seebeck coefficient (S) and electrical conductivity (σ) measurements are performed at room temperature on pellets obtained by spark plasma sintering. An increase of power factors (S2·σ) from around 50 up to 500 μW K−2 m−1 is observed for differently doped compounds. In several series of samples, we observed an optimum of power factor above 500 μW K−2 m−1 at room temperature for a chlorine equivalence of 0.25 mol. % BiCl3. The obtained results are plotted on a semilogarithmic log (σ) versus S graph to demonstrate that a very strong linear trend that limits the power factor around 500 μW K−2 m−1 exists. Further improvement of Bi2S3 as thermoelectric material will require finding new doping modes that will break through the observed trend. The results of stability tests demonstrate that properties of optimally doped Bi2S3 are stable.
Ferroelectricity in high-density H2O ice
Authors: Caracas Razvan , Hemley Russell J.
Published: April 2015

The origin of longstanding anomalies in experimental studies of the dense solid phases of H2O ices VII, VIII, and X is examined using a combination of first-principles theoretical methods. We find that a ferroelectric variant of ice VIII is energetically competitive with the established antiferroelectric form under pressure. The existence of domains of the ferroelectric form within anti-ferroelectric ice can explain previously observed splittings in x-ray diffraction data. The ferroelectric form is stabilized by density and is accompanied by the onset of spontaneous polarization. The presence of local electric fields triggers the preferential parallel orientation of the water molecules in the structure, which could be stabilized in bulk using new high-pressure techniques.
Comparative measurements of plasma potential with ball-pen and Langmuir probe in low-temperature magnetized plasma
Authors: Zanáška M. , Adámek J. , Peterka M. , Kudrna P. , Tichý M.
Published: April 2015

The ball-pen probe (BPP) is used for direct plasma potential measurements in magnetized plasma. The probe can adjust the ratio of the electron and ion saturation currents Isat−/Isat+ to be close to one and therefore its I-V characteristic becomes nearly symmetric. If this is achieved, the floating potential of the BPP is close to the plasma potential. Because of its rather simple construction, it offers an attractive probe for measurements in magnetized plasma. Comparative measurements of plasma potential by BPPs of different dimensions as well as one Langmuir probe (LP) in an argon discharge plasma of a cylindrical magnetron were performed at various experimental conditions. An additional comparison by an emissive probe was also performed. All these types of probes provide similar values of plasma potential in a wide range of plasma parameters. Our results for three different BPP dimensions indicate that the BPP can be operated in a cylindrical magnetron DC argon discharge if the value of the ratio of the magnetic field and neutral gas pressure, B/p, is greater than approximately 10 mT/Pa.
Electron impact excitation of helium in Debye plasma
Authors: Diallo S. , Gomis L. , Faye I. G. , Tall M. S. , Diédhiou I. , Diatta C. S. , Zammit M.
Published: April 2015

The probability, differential, and integral scattering cross sections of the 11S→21S and 11S→21P transitions of helium have been calculated in the first Born approximation. The projectile-target interactions depending on the temperature and the density of plasma are described by the Debye-Hückel model. Wave functions of the target before and after collision were modeled by non orthogonal Hartree-Fock orbitals. The wave functions parameters are calculated with the Ritz variational method. We improve our unscreened first Born approximation integral cross sections by using the BE-scaled (B stands for binding energy and E excitation energy) method. The second Born approximation has also been used to calculate the excitation cross sections in Debye plasma. Our calculations are compared to other theoretical and experimental results where applicable.
Atomistic simulation of laser-pulse surface modification: Predictions of models with various length and time scales
Authors: Starikov Sergey V. , Pisarev Vasily V.
Published: April 2015

In this work, the femtosecond laser pulse modification of surface is studied for aluminium (Al) and gold (Au) by use of two-temperature atomistic simulation. The results are obtained for various atomistic models with different scales: from pseudo-one-dimensional to full-scale three-dimensional simulation. The surface modification after laser irradiation can be caused by ablation and melting. For low energy laser pulses, the nanoscale ripples may be induced on a surface by melting without laser ablation. In this case, nanoscale changes of the surface are due to a splash of molten metal under temperature gradient. Laser ablation occurs at a higher pulse energy when a crater is formed on the surface. There are essential differences between Al ablation and Au ablation. In the first step of shock-wave induced ablation, swelling and void formation occur for both metals. However, the simulation of ablation in gold shows an additional athermal type of ablation that is associated with electron pressure relaxation. This type of ablation takes place at the surface layer, at a depth of several nanometers, and does not induce swelling.
On the interplay of the potential energy and dipole moment surfaces in controlling the infrared activity of liquid water
Authors: Medders Gregory R. , Paesani Francesco
Published: April 2015

Infrared vibrational spectroscopy is a valuable tool for probing molecular structure and dynamics. However, obtaining an unambiguous molecular-level interpretation of the spectral features is made difficult, in part, due to the complex interplay of the dipole moment with the underlying vibrational structure. Here, we disentangle the contributions of the potential energy surface (PES) and dipole moment surface (DMS) to the infrared spectrum of liquid water by examining three classes of models, ranging in complexity from simple point charge models to accurate representations of the many-body interactions. By decoupling the PES from the DMS in the calculation of the infrared spectra, we demonstrate that the PES, by directly modulating the vibrational structure, primarily controls the width and position of the spectroscopic features. Due to the dependence of the molecular dipole moment on the hydration environment, many-body electrostatic effects result in a ∼100 cm−1 redshift in the peak of the OH stretch band. Interestingly, while an accurate description of many-body collective motion is required to generate the correct (vibrational) structure of the liquid, the infrared intensity in the OH stretching region appears to be a measure of the local structure due to the dominance of the one-body and short-ranged two-body contributions to the total dipole moment.
Slip length crossover on a graphene surface
Authors: Liang Zhi , Keblinski Pawel
Published: April 2015

Using equilibrium and non-equilibrium molecular dynamics simulations, we study the flow of argon fluid above the critical temperature in a planar nanochannel delimited by graphene walls. We observe that, as a function of pressure, the slip length first decreases due to the decreasing mean free path of gas molecules, reaches the minimum value when the pressure is close to the critical pressure, and then increases with further increase in pressure. We demonstrate that the slip length increase at high pressures is due to the fact that the viscosity of fluid increases much faster with pressure than the friction coefficient between the fluid and the graphene. This behavior is clearly exhibited in the case of graphene due to a very smooth potential landscape originating from a very high atomic density of graphene planes. By contrast, on surfaces with lower atomic density, such as an (100) Au surface, the slip length for high fluid pressures is essentially zero, regardless of the nature of interaction between fluid and the solid wall.
Spin Hall switching of the magnetization in Ta/TbFeCo structures with bulk perpendicular anisotropy
Authors: Zhao Zhengyang , Jamali Mahdi , Smith Angeline K. , Wang Jian-Ping
Published: April 2015

Spin-orbit torques are studied in Ta/TbFeCo/MgO patterned structures, where the ferrimagnetic material TbFeCo provides a strong bulk perpendicular magnetic anisotropy (bulk-PMA) independent of the interfaces. The current-induced magnetization switching in TbFeCo is investigated in the presence of a perpendicular, longitudinal, or transverse field. An unexpected partial-switching phenomenon is observed in the presence of a transverse field unique to our bulk-PMA material. It is found that the anti-damping torque related with spin Hall effect is very strong, and a spin Hall angle is determined to be 0.12. The field-like torque related with Rashba effect is unobservable, suggesting that the interface play a significant role in Rashba-like torque.
Current-driven vortex domain wall motion in wire-tube nanostructures
Authors: Espejo A. P. , Vidal-Silva N. , López-López J. A. , Goerlitz D. , Nielsch K. , Escrig J.
Published: April 2015

We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.
Enhancement of lower critical field by reducing the thickness of epitaxial and polycrystalline MgB2 thin films
Authors: Tan Teng , Wolak M. A. , Acharya Narendra , Krick Alex , Lang Andrew C. , Sloppy Jennifer , Taheri Mitra L. , Civale L. , Chen Ke , Xi X. X.
Published: April 2015

For potential applications in superconducting RF cavities, we have investigated the properties of polycrystalline MgB2 films, including the thickness dependence of the lower critical field Hc1. MgB2 thin films were fabricated by hybrid physical-chemical vapor deposition on (0001) SiC substrate either directly (for epitaxial films) or with a MgO buffer layer (for polycrystalline films). When the film thickness decreased from 300 nm to 100 nm, Hc1 at 5 K increased from around 600 Oe to 1880 Oe in epitaxial films and to 1520 Oe in polycrystalline films. The result is promising for using MgB2/MgO multilayers to enhance the vortex penetration field.
Giant magnetocaloric effect and temperature induced magnetization jump in GdCrO3 single crystal
Authors: Yin L. H. , Yang J. , Kan X. C. , Song W. H. , Dai J. M. , Sun Y. P.
Published: April 2015

We report on a systematic study of the single-crystal GdCrO3, which shows various novel magnetic features, such as temperature-induced magnetization reversal (TMR), temperature-induced magnetization jump (TMJ), spin reorientation, and giant magnetocaloric effect (MCE). In the field-cooled cooling process with modest magnetic field along the c axis, GdCrO3 first shows a TMR at Tcomp∼120−130 K and then an abrupt TMJ with a sign change of magnetization at Tjump∼52−120 K, and finally a spin reorientation at TSR∼4−7 K. Interestingly, the remarkable TMJ behavior, which was not reported ever before, persists at higher fields up to 10 kOe even when TMR disappears. In addition, giant MCE with the maximum value of magnetic entropy change reaching ∼31.6 J/kg K for a field change of 44 kOe was also observed in GdCrO3 single crystal, suggesting it could be a potential material for low-T magnetic refrigeration. A possible mechanism for these peculiar magnetic behaviors is discussed based on the various competing magnetic interactions between the 3d electrons of Cr3+ ions and 4f electrons of Gd3+ ions.
Note: A simple method to suppress the artificial noise for velocity map imaging spectroscopy
Authors: Qin Zhengbo , Li Chunsheng , Qu Zehua , Tang Zichao
Published: April 2015

A simple method has been proposed to suppress artificial noise from the counts with respect to the central line (or point) for the reconstructed 3D images with cylindrical symmetry in the velocity-map imaging spectroscopy. A raw 2D projection around the z-axis (usually referred to as central line) for photodetachment, photoionization, or photodissociation experiments is pre-processed via angular tailored method to avoid the signal counts distributed near the central line (or point). Two types of photoelectron velocity-map imaging (O− and Au− ⋅ NH3) are demonstrated to give rise to the 3D images with significantly reduced central line noise after pre-processing operation. The major advantages of the pre-operation are the ability of suppression of central-line noise to resolve weak structures or vibrational excitation in atoms or molecules near photon threshold.