bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface directed reversible imidazole ligation to nickel(ii) octaethylporphyrin at the solution/solid interface: a single molecule level study
Authors: Nandi Goutam , Chilukuri Bhaskar , Hipps K. W. , Mazur Ursula
Published: July 2016

STM and DFT calculations are used to study the reversible binding of imidazole to NiOEP supported on HOPG in solution.
Hypervalent iodine(iii) fluorinations of alkenes and diazo compounds: new opportunities in fluorination chemistry
Authors: Kohlhepp Stefanie V. , Gulder Tanja
Published: July 2016

The review gives a timely overview on the fluoro functionalization of alkenes and diazo compounds using hypervalent λ3-iodane chemistry.
Correction: The rise of organic electrode materials for energy storage
Authors: Schon Tyler B. , McAllister Bryony T. , Li Peng-Fei , Seferos Dwight S.
Published: July 2016

Correction for ‘The rise of organic electrode materials for energy storage’ by Tyler B. Schon et al., Chem. Soc. Rev., 2016, DOI: 10.1039/c6cs00173d.
Interaction of alkali acetates with silica supported PdAu
Authors: Hanrieder Elisabeth K. , Jentys Andreas , Lercher Johannes A.
Published: July 2016

The temperature dependence of the interaction of PdAu alloy particles with alkali acetate promoters (MOAc; M+= Li+, Na+, K+, Cs+) was studied by X-ray absorption and infrared spectroscopy as well asin situX-ray diffraction.
Metallogel formation in aqueous DMSO by perfluoroalkyl decorated terpyridine ligands
Authors: Tatikonda Rajendhraprasad , Bhowmik Sandip , Rissanen Kari , Haukka Matti , Cametti Massimo
Published: July 2016

In this paper, we present a series of stable and thermoreversible metallogels formed by the combination of terpyridine based ligands decorated with perfluorinated C8F17 tags and several divalent d-block metal salts.
A closer look on the coordination of soft nitrogen-donor ligands to Cm(iii): SO3-Ph-BTBP
Authors: Trumm M. , Wagner C. , Schimmelpfennig B. , Geist A. , Panak P. J.
Published: July 2016

The combination of theory, VSBS and TRLFS revealed new insights into the coordination structure of [Cm(SO3-Ph-BTBP)2]5−.
Complexes of the tripodal phosphine ligands PhSi(XPPh2)3(X = CH2, O): synthesis, structure and catalytic activity in the hydroboration of CO2
Authors: Aloisi Alicia , Berthet Jean-Claude , Genre Caroline , Thuéry Pierre , Cantat Thibault
Published: July 2016

The coordination chemistry of Fe2+, Co2+and Cu+ions was explored with the ligands PhSi{CH2PPh2}3(1) and PhSi{OPPh2}3(2), so as to evaluate the impact of the electronic properties of the tripodal phosphorus ligands on the structure and reactivity of the corresponding complexes.
Design, synthesis and optical properties of small molecules based on dithieno[3,2-b:2′,3′-d]stannole and stannafluorene
Authors: Gu Chuantao , Zhu Dangqiang , Qiu Meng , Han Liangliang , Wen Shuguang , Li Yonghai , Yang Renqiang
Published: July 2016

A series of stable Sn-containing heteroaromatic conjugated oligomers, dialkyl dithieno[3,2-b:2′,3′-d]stannole (DTSn) and stannafluorene (SnF) derivatives, were designed and synthesized.
New exploration towards dinuclear iridium(ii) complexes materials under chlorine-bridged precursor
Authors: Song Ming-Xing , Li Yuan , Xu Duo , Deng Rui-Ping , Bai Fu-Quan , Qin Zheng-Kun
Published: July 2016

As an important precursor for synthesizing Iridium complex, two similar chlorine-bridged dinuclear complexes, which are bright, were studied by experiment and theory.
Novel mono-cationic fluorescent probes based on different central π-conjugated bridges for two-photon bioimaging of cellular nuclei
Authors: Chi Shuheng , Li Liang , Wu Yiqun
Published: July 2016

A series of novel pyridine mono-cationic two-photon fluorescent probes based on different central π-conjugated bridges, fluorenone (W-pyI), dibenzothiophene (S-pyI), and dibenzofuran (F-pyI), were prepared and studied for improving photostability in bioimaging applications.
Thieno[3,2-b]thiophene based electrochromic polymers: experimental cum theoretical appraisal of the EDOT position
Authors: Zhu Xiaosi , Zhu Yanan , Murtaza Imran , Shi Jingjing , He Yaowu , Xu Panpan , Zhu Mengmeng , Goto Osamu , Meng Hong
Published: July 2016

P(2,5-BTE) reflects color from purple to grey-blue, while P(3,6-BTE) switches from orange-red to cyan.
Economical synthesis of cyclic carbonates from carbon dioxide and halohydrins using K2CO3
Authors: Hirose Takuji , Shimizu Shinsuke , Qu Shujie , Shitara Hiroaki , Kodama Koichi , Wang Lin
Published: July 2016

Highly simple, economical and selective synthesis of five-membered cyclic carbonates was presented as a reaction of CO2 and various 1,2-halohydrins using K2CO3 at 1 atm of CO2 and 30 °C in DMF.
Electro-catalysis of carbon black or titanium sub-oxide supported Pd–Gd towards formic acid electro-oxidation
Authors: He Nan , Qin Chuanguang , Wang Rumin , Ma Shuhui , Wang Yi , Qi Tao
Published: July 2016

Carbon black supported Pd–Gd catalysts (Pd–xGd/C, x is weight percent in catalyst) with different amounts of Gd were prepared by a simultaneous reduction reaction with sodium borohydride in aqueous solution.
Simultaneous fabrication of bifunctional Cu(i)/Ce(iv) sites in silica nanopores using a guests-redox strategy
Authors: Yin Yu , Zhu Jing , Liu Xiao-Qin , Tan Peng , Xue Ding-Ming , Xing Zhi-Min , Sun Lin-Bing
Published: July 2016

The bifunctional materials prepared using a guests-redox strategy show excellent performance in gas separation of C2H4 from C2H6.
A highly sensitive fluorescent probe for detection of hydrazine in gas and solution phases based on the Gabriel mechanism and its bioimaging
Authors: Maji Rajkishor , Mahapatra Ajit Kumar , Maiti Kalipada , Mondal Sanchita , Ali Syed Samim , Sahoo Prithidipa , Mandal Sukhendu , Uddin Md Raihan , Goswami Shyamaprosad , Quah Ching Kheng , Fun Hoong-Kun
Published: July 2016

A new probe 2-benzo[1,2,5]thiadiazol-4-yl-isoindole-1,3-dione (BTI) based on the Gabriel reaction was developed for hydrazine which shows promising selectivity towards hydrazine over other analytes.
Nanocrystalline FeOClx grafted MCM-41 as active mesoporous catalyst for the solvent-free multi-condensation reaction
Authors: Dumbre Deepa , Amin Mohammad Hassan , Loh Qing , Choudahry Vasant R. , Selvakannan P. R. , Bhargava Suresh K.
Published: July 2016

Multi-component condensation of aromatic aldehydes, napthols, urea (or amides) catalytically converted into medicinally important amidoalkylnapthols using the thermally activated FeC13/MCM-41 catalyst.
A mesoporous fluorescent sensor based on ZnO nanorods for the fluorescent detection and selective recognition of tetracycline
Authors: Zhou Zhiping , Lu Kai , Wei Xiao , Hao Tongfan , Xu Yeqing , Lv Xiaodong , Zhang Yufeng
Published: July 2016

Schematic for preparation of the mesoporous MIPs-ZnO NRs and non-mesoporous MIPs-ZnO NRs.
Toward production of pure 13C hyperpolarized metabolites using heterogeneous parahydrogen-induced polarization of ethyl[1-13C]acetate
Authors: Kovtunov K. V. , Barskiy D. A. , Salnikov O. G. , Shchepin R. V. , Coffey A. M. , Kovtunova L. M. , Bukhtiyarov V. I. , Koptyug I. V. , Chekmenev E. Y.
Published: July 2016

Here, we report the production of 13C-hyperpolarized ethyl acetate via heterogeneously catalyzed pairwise addition of parahydrogen to vinyl acetate over TiO2-supported rhodium nanoparticles, followed by magnetic field cycling.
Antibacterial bioadhesive layer-by-layer coatings for orthopedic applications
Authors: Carvalho A. L. , Vale A. C. , Sousa M. P. , Barbosa A. M. , Torrado E. , Mano J. F. , Alves N. M.
Published: July 2016

In this study, thin LbL films were produced by combining the adhesive properties of the hyaluronic acid–dopamine conjugate with the bioactivity and bactericidal properties of silver doped bioactive glass nanoparticles.
Structure–activity relationship studies of symmetrical cationic bolasomes as non-viral gene vectors
Authors: Huang Zheng , Zhang Yi-Mei , Cheng Qian , Zhang Ji , Liu Yan-Hong , Wang Bing , Yu Xiao-Qi
Published: July 2016

Bolalipids based on lysine or cyclen headgroups were synthesized and their structure–activity relationship as gene delivery vectors was studied.
Conjugated polymer-based electrochromics: materials, device fabrication and application prospects
Authors: Neo Wei Teng , Ye Qun , Chua Soo-Jin , Xu Jianwei
Published: July 2016

The recent developments and trends of electrochromic conjugated polymers and their devices are highlighted in this review.
Multi‐user radar waveforms based on doubly coded Costas signals
Authors: Touati Nadjah , Tatkeu Charles , Rivenq Atika , Thierry Chonavel , El Hillali Yassin
Published: July 2016

In multi‐user radar applications, waveforms that show low cross‐correlation and cross‐ambiguity sidelobes are needed. In this study, the authors propose to generate novel multi‐user waveforms using a modified version of Costas signals, namely doubly coded Costas signals. The modification principle consists in combining two Costas codes by coding the sub‐pulses of the main code by another code. First, the sub‐pulse Costas code diversity is used to generate waveforms with low cross‐correlation sidelobes and good auto‐correlation properties while using the same main Costas code. Conditions on sub‐pulse codes are drawn by optimising the auto‐ and cross‐ambiguity functions around the mainlobe. Subsequently, the authors extended the approach to the use of several main Costas codes selected according to particular criteria. Hence, since both main and sub‐pulse Costas codes are exploited, the total number of generated signals is increased significantly compared with a usage of standard Costas codes. This can be suitable for multi‐user radar applications with a large number of simultaneous users.
Narratives of Choice: Marriage, Choosing Right and the Responsibility of Agency in Urban Middle-Class Sri Lanka
Authors: Abeyasekera Asha L.
Published: July 2016

The shift to companionate marriage in South Asia and elsewhere is widely read as a move from ‘tradition’ to ‘modernity’ resulting in an expansion of individual agency, especially for women. This paper critically examines the narratives of urban middle-class women in Sri Lanka spanning three generations to illustrate that rather than indicating a radical shift in the way they negotiated between individual desires and social norms, the emphasis on ‘choice’ signals a shift in the narrative devices used in the presentation of the ‘self’. The paper illustrates how young women's narratives about marriage appear to suggest ‘modernity’ as inevitable—that its processes are reconstituting the person who, less constrained by ‘tradition’ and collective expectations, is now experiencing greater freedom in the domain of marriage. However, it also shows how urban middle-class families in Sri Lanka have collectively invested in the narrative of choice through which ‘a choosing person’ is consciously created as a mark of the family's modernity and progress. Rather than signalling freedom, these narratives about choice reveal how women are often burdened with the risks and responsibility of agency. The paper illustrates that the ‘choosing person’ is produced through narratives that emphasise agency as a responsibility that must be exercised with caution because women are expected by and obligated to their families to make the ‘right’ choices. Hence, a closer look at the individualised ‘choosing person’ reveals a less unitary, relational self with permeable boundaries embedded within and accountable to family and kinship.
History as Narration: Resistance and Subaltern Subjectivity in Micaela Bastidas’ ‘Confession’
Authors: Schmidt Ella
Published: July 2016

This paper focusses on the negotiations in which many subaltern peoples engage within contexts of unequal power relations in colonial settings like eighteenth-century Peru. The trial and ‘confession’ of Micaela Bastidas, an indigenous mestizo and wife of the Inca rebel Túpac Amaru II, allows for an analysis of the complexity of her subjectivity and agency, both as products of colonial impositions and Andean notions of gender complementarity and power. As a woman, wife of a noble curaca and member of a conquered indigenous population, she defied rigidly bipolar colonial ethnic and gender norms. Skilfully engaging in ‘rituals of subordination’ through the manipulation of discriminatory colonial expectations, Micaela refused to share what was expected of her, subverting colonial gender and power hierarchies, albeit momentarily.
‘I Pray for the Factory to Continue Earning Money’: The Familial Factory Regime of the ‘Sun’ Food Factory in Turkey
Authors: Erdogan Ermine
Published: July 2016

This paper explores the factory regime in the ‘Sun' 1 food processing factory in Turkey, drawing on participant observation in the factory, informal interviews with women workers and in-depth interviews with the managers of the factory's ‘gherkin department’ in which I worked. This paper argues that the ‘Sun’ bottling and canning factory is best understood through my concept of the ‘familial factory regime’. By ‘familial factory regime’ I mean a factory regime in which the features of the extended patriarchal family are used to manage the labour force by obtaining women workers’ consent. Indeed, the paper suggests that there is a tendency for patriarchy to be reconstituted in the workplace through the presence of a familial factory regime.

1 ‘Sun’ is a pseudonymous name of the factory, which I gave it because of the heat.
General slip regime permeability model for gas flow through porous media
Authors: Zhou Bo , Jiang Peixue , Xu Ruina , Ouyang Xiaolong
Published: July 2016

A theoretical effective gas permeability model was developed for rarefied gas flow in porous media, which holds over the entire slip regime with the permeability derived as a function of the Knudsen number. This general slip regime model (GSR model) is derived from the pore-scale Navier-Stokes equations subject to the first-order wall slip boundary condition using the volume-averaging method. The local closure problem for the volume-averaged equations is studied analytically and numerically using a periodic sphere array geometry. The GSR model includes a rational fraction function of the Knudsen number which leads to a limit effective permeability as the Knudsen number increases. The mechanism for this behavior is the viscous fluid inner friction caused by converging-diverging flow channels in porous media. A linearization of the GSR model leads to the Klinkenberg equation for slightly rarefied gas flows. Finite element simulations show that the Klinkenberg model overestimates the effective permeability by as much as 33% when a flow approaches the transition regime. The GSR model reduces to the unified permeability model [F. Civan, “Effective correlation of apparent gas permeability in tight porous media,” Transp. Porous Media 82, 375 (2010)] for the flow in the slip regime and clarifies the physical significance of the empirical parameter b in the unified model.
Analysis of Al diffusion processes in TiN barrier layers for the application in silicon solar cell metallization
Authors: Kumm J. , Samadi H. , Chacko R. V. , Hartmann P. , Wolf A.
Published: July 2016

An evaporated Al layer is known as an excellent rear metallization for highly efficient solar cells, but suffers from incompatibility with a common solder process. To enable solar cell-interconnection and module integration, in this work the Al layer is complemented with a solder stack of TiN/Ti/Ag or TiN/NiV/Ag, in which the TiN layer acts as an Al diffusion barrier. X-ray photoelectron spectroscopy measurements prove that diffusion of Al through the stack and the formation of an Al2O3 layer on the stack's surface are responsible for a loss of solderability after a strong post-metallization anneal, which is often mandatory to improve contact resistance and passivation quality. An optimization of the reactive TiN sputter process results in a densification of the TiN layer, which improves its barrier quality against Al diffusion. However, measurements with X-ray diffraction and scanning electron microscopy show that small grains with vertical grain boundaries persist, which still offer fast diffusion paths. Therefore, the concept of stuffing is introduced. By incorporating oxygen into the grain boundaries of the sputtered TiN layer, Al diffusion is strongly reduced as confirmed by secondary ion mass spectroscopy profiles. A quantitative analysis reveals a one order of magnitude lower Al diffusion coefficient for stuffed TiN layers. This metallization system maintains its solderability even after strong post-metallization annealing at 425 °C for 15 min. This paper thus presents an industrially feasible, conventionally solderable, and long-term stable metallization scheme for highly efficient silicon solar cells.
Room temperature dual ferroic behaviour of ball mill synthesized NdFeO3 orthoferrite
Authors: Aparnadevi N. , Saravana Kumar K. , Manikandan M. , Paul Joseph D. , Venkateswaran C.
Published: July 2016

Phase pure NdFeO3 has been achieved using high energy ball milling of oxide precursors with subsequent sintering. It is established that structural arrangement of NdFeO3 regulates the multifunctional feature of the material. Rietveld refinement of the room temperature X-ray diffraction pattern shows that the Fe-O-Fe bond angle significantly favors the super exchange interaction, which is predominantly antiferromagnetic in nature. Magnetization measurement illustrates antiferromagnetic behaviour with a weak ferromagnetic component caused by the canted nature of the Fe3+ spins at room temperature. Absorption bands in the visible ambit, apparent from the UV-Vis diffuse reflectance studies, is found due to the crystal ligand field of octahedral oxygen environment of Fe3+ ions. The direct band gap is estimated to be 2.39 eV from the diffuse reflectance spectrum. The lossy natured ferroelectric loop having a maximum polarization of 0.23 μC/cm2 at room temperature is found to be driven by the non-collinear magnetic structure with reverse Dzyaloshinskii–Moriya effect. Magnetic field has influence on the dielectric constant as evident from the impedance spectroscopy, indicating the strong coupling between ferroelectric and the magnetic structure of NdFeO3.
Resonance in fast-wave amplitude in the periphery of cylindrical plasmas and application to edge losses of wave heating power in tokamaks
Authors: Perkins R. J. , Hosea J. C. , Bertelli N. , Taylor G. , Wilson J. R.
Published: July 2016

Heating magnetically confined plasmas using waves in the ion-cyclotron range of frequencies typically requires coupling these waves over a steep density gradient. This process has produced an unexpected and deleterious phenomenon on the National Spherical Torus eXperiment (NSTX): a prompt loss of wave power along magnetic field lines in front of the antenna to the divertor. Understanding this loss may be key to achieving effective heating and expanding the operational space of NSTX-Upgrade. Here, we propose that a new type of mode, which conducts a significant fraction of the total wave power in the low-density peripheral plasma, is driving these losses. We demonstrate the existence of such modes, which are distinct from surface modes and coaxial modes, in a cylindrical cold-plasma model when a half wavelength structure fits into the region outside the core plasma. The latter condition generalizes the previous hypothesis regarding the occurrence of the edge losses and may explain why full-wave simulations predict these losses in some cases but not others. If valid, this condition implies that outer gap control is a potential strategy for mitigating the losses in NSTX-Upgrade in addition to raising the magnetic field or influencing the edge density.
The repopulation of electronic states upon vibrational excitation of niobium carbide clusters
Authors: Chernyy V. , Logemann R. , Bakker J. M. , Kirilyuk A.
Published: July 2016

We study the infrared (IR) resonant heating of neutral niobium carbide clusters probed through ultraviolet photoionization spectroscopy. The IR excitation not only changes the photoionization spectra for the photon energies above the ionization threshold, but also modulates ion yield for energies significantly below it. An attempt to describe the experimental spectra using either Fowler’s theory or thermally populated vibrational states was not successful. However, the data can be fully modeled by vibrationally and rotationally broadened discrete electronic levels obtained from Density Functional Theory (DFT) calculations. The application of this method to spectra with different IR pulse energies not only yields information about the excited electronic states in the vicinity of the HOMO level, populated by manipulation of the vibrational coordinates of a cluster, but also can serve as an extra indicator for the cluster isomeric structure and corresponding DFT-calculated electronic levels.
The first potential energy surfaces for the C6H−–H2 and C6H−–He collisional systems and their corresponding inelastic cross sections
Authors: Walker Kyle M. , Dumouchel Fabien , Lique François , Dawes Richard
Published: July 2016

Molecular anions have recently been detected in the interstellar and circumstellar media. Accurate modeling of their abundance requires calculations of collisional data with the most abundant species that are usually He atoms and H2 molecules. In this paper, we focus on the collisional excitation of the first observed molecular anion, C6H−, by He and H2. Theoretical calculations of collisional cross sections rely generally on ab initio interaction potential energy surfaces (PESs). Hence, we present here the first PESs for the C6H−–H2 and C6H−–He van der Waals systems. The ab initio energy data for the surfaces were computed at the explicitly correlated coupled cluster with single, double, and scaled perturbative triple excitations level of theory. The method of interpolating moving least squares was used to construct 4D and 2D analytical PESs from these data. Both surfaces are characterized by deep wells and large anisotropies. Analytical models of the PESs were used in scattering calculations to obtain cross sections for low-lying rotational transitions. As could have been anticipated, important differences exist between the He and H2 cross sections. Conversely, no significant differences exist between the collisions of C6H− with the two species of H2 (para- and ortho-H2). We expect that these new data will help in accurately determining the abundance of the C6H− anions in space.
Modelling the effect of acoustic waves on nucleation
Authors: Haqshenas S. R. , Ford I. J. , Saffari N.
Published: July 2016

A phase transformation in a metastable phase can be affected when it is subjected to a high intensity ultrasound wave. In this study we determined the effect of oscillation in pressure and temperature on a phase transformation using the Gibbs droplet model in a generic format. The developed model is valid for both equilibrium and non-equilibrium clusters formed through a stationary or non-stationary process. We validated the underlying model by comparing the predicted kinetics of water droplet formation from the gas phase against experimental data in the absence of ultrasound. Our results demonstrated better agreement with experimental data in comparison with classical nucleation theory. Then, we determined the thermodynamics and kinetics of nucleation and the early stage of growth of clusters in an isothermal sonocrystallisation process. This new contribution shows that the effect of pressure on the kinetics of nucleation is cluster size-dependent in contrast to classical nucleation theory.
Valence and lowest Rydberg electronic states of phenol investigated by synchrotron radiation and theoretical methods
Authors: Limão-Vieira P. , Duflot D. , Ferreira da Silva F. , Lange E. , Jones N. C. , Hoffmann S. V. , Śmiałek M. A. , Jones D. B. , Brunger M. J.
Published: July 2016

We present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3–10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional theory and the equation-of-motion coupled cluster method restricted to single and double excitations level. These have been used in the assignment of valence and Rydberg transitions of the phenol molecule. The VUV spectrum reveals several new features not previously reported in the literature, with particular reference to the 6.401 eV transition, which is here assigned to the 3sσ/σ∗(OH)←3π(3a″) transition. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of phenol in the earth’s atmosphere (0–50 km).
Monotone Riemannian metrics and dynamic structure factor in condensed matter physics
Authors: Tonchev N. S.
Published: July 2016

An analytical approach is developed to the problem of computation of monotone Riemannian metrics (e.g., Bogoliubov-Kubo-Mori, Bures, Chernoff, etc.) on the set of quantum states. The obtained expressions originate from the Morozova, C̆ encov, and Petz correspondence of monotone metrics to operator monotone functions. The used mathematical technique provides analytical expansions in terms of the thermodynamic mean values of iterated (nested) commutators of a model Hamiltonian T with the operator S involved through the control parameter h. Due to the sum rules for the frequency moments of the dynamic structure factor, new presentations for the monotone Riemannian metrics are obtained. Particularly, relations between any monotone Riemannian metric and the usual thermodynamic susceptibility or the variance of the operator S are discussed. If the symmetry properties of the Hamiltonian are given in terms of generators of some Lie algebra, the obtained expansions may be evaluated in a closed form. These issues are tested on a class of model systems studied in condensed matter physics.
Nanoscale thermometry by scanning thermal microscopy
Authors: Menges Fabian , Riel Heike , Stemmer Andreas , Gotsmann Bernd
Published: July 2016

Measuring temperature is a central challenge in nanoscience and technology. Addressing this challenge, we report the development of a high-vacuum scanning thermal microscope and a method for non-equilibrium scanning probe thermometry. The microscope is built inside an electromagnetically shielded, temperature-stabilized laboratory and features nanoscopic spatial resolution at sub-nanoWatt heat flux sensitivity. The method is a dual signal-sensing technique inferring temperature by probing a total steady-state heat flux simultaneously to a temporally modulated heat flux signal between a self-heated scanning probe sensor and a sample. Contact-related artifacts, which so far limit the reliability of nanoscopic temperature measurements by scanning thermal microscopy, are minimized. We characterize the microscope’s performance and demonstrate the benefits of the new thermometry approach by studying hot spots near lithographically defined constrictions in a self-heated metal interconnect.
Reconstruction of elongated bubbles fusing the information from multiple optical probes through a Bayesian inference technique
Authors: Chakraborty Shubhankar , Roy Chaudhuri Partha , Das Prasanta Kr.
Published: July 2016

In this communication, a novel optical technique has been proposed for the reconstruction of the shape of a Taylor bubble using measurements from multiple arrays of optical sensors. The deviation of an optical beam passing through the bubble depends on the contour of bubble surface. A theoretical model of the deviation of a beam during the traverse of a Taylor bubble through it has been developed. Using this model and the time history of the deviation captured by the sensor array, the bubble shape has been reconstructed. The reconstruction has been performed using an inverse algorithm based on Bayesian inference technique and Markov chain Monte Carlo sampling algorithm. The reconstructed nose shape has been compared with the true shape, extracted through image processing of high speed images. Finally, an error analysis has been performed to pinpoint the sources of the errors.
An AC modulated near infrared gain calibration system for a “Violin-Mode” transimpedance amplifier, intended for advanced LIGO suspensions
Authors: Lockerbie N. A. , Tokmakov K. V.
Published: July 2016

The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation, and a “tall-thin” rectangular silicon photodiode detector, which together were to bracket the fibre under test. The photodiode was positioned so as to be sensitive (primarily) to transverse “Violin-Mode” vibrations of such a fibre, via the oscillatory movement of the shadow cast by the fibre, as this moved across the face of the detector. In this prototype shadow sensing system the photodiode was interfaced to a purpose-built transimpedance amplifier, this having both AC and DC outputs. A quasi-static calibration was made of the sensor’s DC responsivity, i.e., incremental rate of change of output voltage versus fibre position, by slowly scanning a fused-silica fibre sample transversely through the illuminating beam. The work reported here concerns the determination of the sensor’s more important AC (Violin-Mode) responsivity. Recognition of the correspondence between direct AC modulation of the source, and actual Violin-Mode signals, and of the transformative role of the AC/DC gain ratio for the amplifier, at any modulation frequency, f, resulted in the construction of the AC/DC calibration source described here. A method for determining in practice the transimpedance AC/DC gain ratio of the photodiode and amplifier, using this source, is illustrated by a specific numerical example, and the gain ratio for the prototype sensing system is reported over the frequency range 1 Hz–300 kHz. In fact, a maximum DC responsivity of 1.26 kV.m−1 was measured using the prototype photodiode sensor and amplifier discussed here. Therefore, the measured AC/DC transimpedance gain ratio of 922.5 for this sensor, at 500 Hz, translated into a maximum Violin-Mode (AC) responsivity of (1.16 ± 0.05) MV m−1, at that frequency.
Contributed Review: A new synchronized source solution for coherent Raman scattering microscopy
Authors: Wang Ke , Wang Yuxin , Liang Runfu , Wang Jiaqi , Qiu Ping
Published: July 2016

Based on vibrational spectroscopy, coherent Raman Scattering (CRS) microscopy allows label-free imaging of biological and chemical samples with endogenous image contrast. Two-color, synchronized picosecond pulses are typically used for high spectral resolution imaging, which in turn constitutes a dramatic laser source challenge for CRS microscopy. Recently, synchronized time-lens source, inspired from ultrafast optical signal processing, has emerged as a promising laser source solution and has found application in various modalities of CRS microscopy. Time-lens is based on space-time analogy, which uses a “lens” in the time domain to compress long optical pulses or even continuous waves to ultrashort pulses, mimicking a lens in the space domain. Phase and intensity modulators driven with electrical signals are used in the time-lens source for picosecond pulse generation. As a result, the time-lens source is highly versatile and naturally compatible with modulation capabilities. More importantly, if the electrical signals used to drive the time-lens source are derived from other laser sources, such as mode-locked lasers, then synchronization between them can be realized, underlying the physics of a synchronized time-lens source. In this paper, we review recent progress on the basic principle, design of the synchronized time-lens source, and its applications to CRS microscopy of both biological and chemical samples.
Cross-calibration of Fuji TR image plate and RAR 2492 x-ray film to determine the response of a DITABIS Super Micron image plate scanner
Authors: Dunham G. , Harding E. C. , Loisel G. P. , Lake P. W. , Nielsen-Weber L. B.
Published: July 2016

Fuji TR image plate is frequently used as a replacement detector medium for x-ray imaging and spectroscopy diagnostics at NIF, Omega, and Z facilities. However, the familiar Fuji BAS line of image plate scanners is no longer supported by the industry, and so a replacement scanning system is needed. While the General Electric Typhoon line of scanners could replace the Fuji systems, the shift away from photo stimulated luminescence units to 16-bit grayscale Tag Image File Format (TIFF) leaves a discontinuity when comparing data collected from both systems. For the purposes of quantitative spectroscopy, a known unit of intensity applied to the grayscale values of the TIFF is needed. The DITABIS Super Micron image plate scanning system was tested and shown to potentially rival the resolution and dynamic range of Kodak RAR 2492 x-ray film. However, the absolute sensitivity of the scanner is unknown. In this work, a methodology to cross calibrate Fuji TR image plate and the absolutely calibrated Kodak RAR 2492 x-ray film is presented. Details of the experimental configurations used are included. An energy dependent scale factor to convert Fuji TR IP scanned on a DITABIS Super Micron scanner from 16-bit grayscale TIFF to intensity units (i.e., photons per square micron) is discussed.
Novel xenon calibration scheme for two-photon absorption laser induced fluorescence of hydrogen
Authors: Elliott Drew , Scime Earl , Short Zachary
Published: July 2016

Two photon absorption laser induced fluorescence (TALIF) measurements of neutral hydrogen and its isotopes are typically calibrated by performing TALIF measurements on krypton with the same diagnostic system and using the known ratio of the absorption cross sections [K. Niemi et al., J. Phys. D 34, 2330 (2001)]. Here we present the measurements of a new calibration method based on a ground state xenon scheme for which the fluorescent emission wavelength is nearly identical to that of hydrogen, thereby eliminating chromatic effects in the collection optics and simplifying detector calibration. We determine that the ratio of the TALIF cross sections of xenon and hydrogen is 0.024 ± 0.001.
Relationship between cap structure and energy gap in capped carbon nanotubes
Authors: Ono Shota , Tanikawa Kousei , Kuwahara Riichi , Ohno Kaoru
Published: July 2016

Revealing a universal relation between geometrical structures and electronic properties of capped carbon nanotubes (CNTs) is one of the current objectives in nanocarbon community. Here, we investigate the local curvature of capped CNTs and define the cap region by a crossover behavior of the curvature energy versus the number of carbon atoms integrated from the tip to the tube region. Clear correlations among the energy gap of the cap localized states, the curvature energy, the number of carbon atoms in the cap region, and the number of specific carbon clusters are observed. The present analysis opens the way to understand the cap states.
Quantum mechanics capacitance molecular mechanics modeling of core-electron binding energies of methanol and methyl nitrite on Ag(111) surface
Authors: Löytynoja T. , Li X. , Jänkälä K. , Rinkevicius Z. , Ågren H.
Published: July 2016

We study a newly devised quantum mechanics capacitance molecular mechanics (QMCMM) method for the calculation of core-electron binding energies in the case of molecules adsorbed on metal surfaces. This yet untested methodology is applied to systems with monolayer of methanol/methyl nitrite on an Ag(111) surface at 100 K temperature. It was found out that the studied C, N, and O 1s core-hole energies converge very slowly as a function of the radius of the metallic cluster, which was ascribed to build up of positive charge on the edge of the Ag slab. Further analysis revealed that an extrapolation process can be used to obtain binding energies that deviated less than 0.5 eV against experiments, except in the case of methanol O 1s where the difference was as large as 1.8 eV. Additional QM-cluster calculations suggest that the latter error can be connected to the lack of charge transfer over the QM–CMM boundary. Thus, the results indicate that the QMCMM and QM-cluster methods can complement each other in a holistic picture of molecule-adsorbate core-ionization studies, where all types of intermolecular interactions are considered.
The molecular gradient using the divide-expand-consolidate resolution of the identity second-order Møller-Plesset perturbation theory: The DEC-RI-MP2 gradient
Authors: Bykov Dmytro , Kristensen Kasper , Kjærgaard Thomas
Published: July 2016

We report an implementation of the molecular gradient using the divide-expand-consolidate resolution of the identity second-order Møller-Plesset perturbation theory (DEC-RI-MP2). The new DEC-RI-MP2 gradient method combines the precision control as well as the linear-scaling and massively parallel features of the DEC scheme with efficient evaluations of the gradient contributions using the RI approximation. We further demonstrate that the DEC-RI-MP2 gradient method is capable of calculating molecular gradients for very large molecular systems. A test set of supramolecular complexes containing up to 158 atoms and 1960 contracted basis functions has been employed to demonstrate the general applicability of the DEC-RI-MP2 method and to analyze the errors of the DEC approximation. Moreover, the test set contains molecules of complicated electronic structures and is thus deliberately chosen to stress test the DEC-RI-MP2 gradient implementation. Additionally, as a showcase example the full molecular gradient for insulin (787 atoms and 7604 contracted basis functions) has been evaluated.
Structural and vibrational study of 2-MethoxyEthylAmmonium Nitrate (2-OMeEAN): Interpretation of experimental results with ab initio molecular dynamics
Authors: Campetella M. , Bovi D. , Caminiti R. , Guidoni L. , Bencivenni L. , Gontrani L.
Published: July 2016

In this work we report an analysis of the bulk phase of 2-methoxyethylammonium nitrate based on ab initio molecular dynamics. The structural and dynamical features of the ionic liquid have been characterized and the computational findings have been compared with the experimental X-ray diffraction patterns, with infrared spectroscopy data, and with the results obtained from molecular dynamics simulations. The experimental infrared spectrum was interpreted with the support of calculated vibrational density of states as well as harmonic frequency calculations of selected gas phase clusters. Particular attention was addressed to the high frequency region of the cation (ω > 2000 cm−1), where the vibrational motions involve the NH3+ group responsible for hydrogen bond formation, and to the frequency range 1200-1400 cm−1 where the antisymmetric stretching mode (ν3) of nitrate is found. Its multiple absorption lines in the liquid arise from the removal of the degeneracy present in the D3h symmetry of the isolated ion. Our ab initio molecular dynamics leads to a rationalization of the frequency shifts and splittings, which are inextricably related to the structural modifications induced by a hydrogen bonding environment. The DFT calculations lead to an inhomogeneous environment.
Ultrafast spontaneous emission modulation of graphene quantum dots interacting with Ag nanoparticles in solution
Authors: Zhao Jianwei , Lu Jian , Wang Liang , Tian Linfan , Deng Xingxia , Tian Lijun , Pan Dengyu , Wang Zhongyang
Published: July 2016

We investigated the strong interaction between graphene quantum dots and silver nanoparticles in solution using time-resolved photoluminescence techniques. In solution, the silver nanoparticles are surrounded by graphene quantum dots and interacted with graphene quantum dots through exciton-plasmon coupling. An ultrafast spontaneous emission process (lifetime 27 ps) was observed in such a mixed solution. This ultrafast lifetime corresponds to the emission rate exceeding 35 GHz, with the purcell enhancement by a factor of ∼12. These experiment results pave the way for the realization of future high speed light sources applications.
Thermal dissociation cavity attenuated phase shift spectroscopy for continuous measurement of total peroxy and organic nitrates in the clean atmosphere
Authors: Sadanaga Yasuhiro , Takaji Ryo , Ishiyama Ayana , Nakajima Kazuo , Matsuki Atsushi , Bandow Hiroshi
Published: July 2016

A thermal dissociation cavity attenuated phase shift spectroscopy (TD-CAPS) instrument was developed for measuring total peroxy nitrates (PNs) and organic nitrates (ONs) concentrations in the clean atmosphere. This instrument is easy to operate and can be applied to continuous measurement of PNs and ONs. A continuously measurable system is convenient to perform observations, especially in remote areas. Three lines (NO2, PNs, and ONs lines) were used for thermal dissociation. The NO2 line contains a quartz tube that is not heated, while the PN and ON lines contain quartz tubes that are heated at 433 K and 633 K, respectively. The concentrations of NO2, NO2 + PNs, and NO2 + PNs + ONs can be obtained from the NO2, PN, and ON lines, respectively. The lower limit values of the detection limit (3σ) for PNs and ONs were estimated to be 21 parts per trillion by volume with an integration time of 2 min. PNs were selectively thermally decomposed in the PNs line and formed NO2 quantitatively. In the ONs line, both PNs and ONs were thermally decomposed to produce NO2 quantitatively, but partial decomposition of HNO3 at 633 K interfered with the ONs measurement. Therefore, a HNO3 scrubber is required before the ONs line. Continuous observations were conducted with the TD-CAPS instrument in a remote area, and the instrument performed well for obtaining PNs and ONs concentrations.
Flux-driven algebraic damping of m = 1 diocotron mode
Authors: Chim Chi Yung , O'Neil Thomas M.
Published: July 2016

Recent experiments with pure electron plasmas in a Malmberg–Penning trap have observed the algebraic damping of m = 1 diocotron modes. Transport due to small field asymmetries produces a low density halo of electrons moving radially outward from the plasma core, and the mode damping begins when the halo reaches the resonant radius r = Rw at the wall of the trap. The damping rate is proportional to the flux of halo particles through the resonant layer. The damping is related to, but distinct from, spatial Landau damping, in which a linear wave-particle resonance produces exponential damping. This paper explains with analytic theory the new algebraic damping due to particle transport by both mobility and diffusion. As electrons are swept around the “cat's eye” orbits of the resonant wave-particle interaction, they form a dipole (m = 1) density distribution. From this distribution, the electric field component perpendicular to the core displacement produces E × B-drift of the core back to the axis, that is, damps the m = 1 mode. The parallel component produces drift in the azimuthal direction, that is, causes a shift in the mode frequency.
Improved transfer efficiencies in radio-frequency-driven recoupling solid-state NMR by adiabatic sweep through the dipolar recoupling condition
Authors: Straasø Lasse A. , Shankar Ravi , Tan Kong Ooi , Hellwagner Johannes , Meier Beat H. , Hansen Michael Ryan , Nielsen Niels Chr. , Vosegaard Thomas , Ernst Matthias , Nielsen Anders B.
Published: July 2016

The homonuclear radio-frequency driven recoupling (RFDR) experiment is commonly used in solid-state NMR spectroscopy to gain insight into the structure of biological samples due to its ease of implementation, stability towards fluctuations/missetting of radio-frequency (rf) field strength, and in general low rf requirements. A theoretical operator-based Floquet description is presented to appreciate the effect of having a temporal displacement of the π-pulses in the RFDR experiment. From this description, we demonstrate improved transfer efficiency for the RFDR experiment by generating an adiabatic passage through the zero-quantum recoupling condition. We have compared the performances of RFDR and the improved sequence to mediate efficient 13CO to 13Cα polarization transfer for uniformly 13C,15N-labeled glycine and for the fibril forming peptide SNNFGAILSS (one-letter amino acid codes) uniformly 13C,15N-labeled at the FGAIL residues. Using numerically optimized sweeps, we get experimental gains of approximately 20% for glycine where numerical simulations predict an improvement of 25% relative to the standard implementation. For the fibril forming peptide, using the same sweep parameters as found for glycine, we have gains in the order of 10%–20% depending on the spectral regions of interest.
Modeling of ribosome dynamics on a ds-mRNA under an external load
Authors: Shakiba Bahareh , Dayeri Maryam , Mohammad-Rafiee Farshid
Published: July 2016

Protein molecules in cells are synthesized by macromolecular machines called ribosomes. According to the recent experimental data, we reduce the complexity of the ribosome and propose a model to express its activity in six main states. Using our model, we study the translation rate in different biological relevant situations in the presence of external force and the translation through the RNA double stranded region in the absence or presence of the external force. In the present study, we give a quantitative theory for translation rate and show that the ribosome behaves more like a Brownian Ratchet motor. Our findings could shed some light on understanding behaviors of the ribosome in biological conditions.
Transmission characteristics of microwave in a glow-discharge dusty plasma
Authors: Jia Jieshu , Yuan Chengxun , Gao Ruilin , Liu Sha , Yue Feng , Wang Ying , Zhou Zhong-Xiang , Wu Jian , Li Hui
Published: July 2016

In this study, the propagation characteristics of electromagnetic wave in a glow discharge plasma with dust particles are experimentally investigated. A helium alternating current glow discharge plasmas have been successfully generated. Measurements of the plasma parameters using Langmuir probes, in the absence of dust particles, provide plasma densities (ne) of 1017 m−3 and electron temperatures (Te) ranging from 2 to 4 eV. Dusty plasmas are made by adding 30 nm radius aluminum oxide (Al2O3) particles into the helium plasma. The density of the dust particle (nd) in the device is about 1011–1012 m−3. The propagation characteristics of electromagnetic waves are determined by a vector network analyzer with 4–6 GHz antennas. An apparent attenuation by the dust is observed, and the measured attenuation data are approximately in accordance with the theoretical calculations. The effects of gas pressure and input power on the propagation are also investigated. Results show that the transmission attenuation increases with the gas pressure and input power, the charged dust particles play a significant role in the microwave attenuation.
Observation of fast expansion velocity with insulating tungsten wires on ∼80 kA facility
Authors: Li M. , Zhang J. H. , Wu J. , Li Y. , Sun T. P. , Wang L. P. , Sheng L. , Qiu M. T. , Mao W. T. , Li X. W.
Published: July 2016

This paper presents experimental results on the effects of insulating coatings on tungsten planar wire array Z-pinches on an 80 kA, 100 ns current facility. Expansion velocity is obviously increased from ∼0.25 km/s to ∼3.5 km/s by using the insulating coatings. It can be inferred that the wire cores are in gaseous state with this fast expansion velocity. An optical framing camera and laser probing images show that the standard wire arrays have typical ablation process which is similar to their behaviors on mega-ampere facilities. The ablation process and precursor plasma are suppressed for dielectric tungsten wires. The wire array implosion might be improved if these phenomena can be reproduced on Mega-ampere facilities.