bluuebunny/crossref_metadata_2025 huggingface dataset:
Unusual sequence length-dependent gold nanoparticles aggregation of the ssDNA sticky end and its application for enzyme-free and signal amplified colorimetric DNA detection
Authors: He Hongfei , Dai Jianyuan , Duan Zhijuan , Zheng Baozhan , Meng Yan , Guo Yong , Dan Xiao
Published: August 2016

It is known that the adsorption of short single-stranded DNA (ssDNA) on unmodified gold nanoparticles (AuNPs) is much faster than that for long ssDNA and thus leads to length-dependent AuNPs aggregation after addition of salt, the color of the solutions sequentially changed from red to blue in accordance with the increase of ssDNA length. However, we found herein that the ssDNA sticky end of hairpin DNA exhibited a completely different adsorption behavior compared to ssDNA, an inverse blue-to-red color variation was observed in the colloid solution with the increase of sticky end length when the length is within a certain range. This unusual sequence length-dependent AuNPs aggregation might be ascribed to the effect of the stem of hairpin DNA. On the basis of this unique phenomenon and catalytic hairpin assembly (CHA) based signal amplification, a novel AuNPs-based colorimetric DNA assay with picomolar sensitivity and specificity was developed. This unusual sequence length-dependent AuNPs aggregation of the ssDNA sticky end introduces a new direction for the AuNPs-based colorimetric assays.
Growth Mechanism and Luminescent Properties of Amorphous SiOx Structures via Phase Equilibrium in Binary System
Authors: Jin Changhyun , Hwang Seon Jae , Cho Myeong Soo , Choi Sun-Woo , Na Han Gil , Park Suyoung , Park Sungsik , Noh Youngwook , Jeong Hakyung , Lee Dongjin
Published: August 2016

Balloon whisk-like and flower-like SiOx tubes with well-dispersed Sn and joining countless SiOx loops together induce intense luminescence characteristics in substrate materials. Our synthetic technique called “direct substrate growth” is based on pre-contamination of the surroundings without the intended catalyst and source powders. The kind of supporting material and pressure of the inlet gases determine a series of differently functionalized tube loops, i.e., the number, length, thickness, and cylindrical profile. SiOx tube loops commonly twist and split to best suppress the total energy. Photoluminescence and confocal laser measurements based on quantum confinement effect of the embedded Sn nanoparticles in the SiOx tube found substantially intense emissions throughout the visible range. These new concepts related to the synthetic approach, pre-pollution, transitional morphology, and permeable nanoparticles should facilitate progress in nanoscience with regard to tuning the dimensions of micro-/nanostructure preparations and the functionalization of customized applications.
Tomato yellow leaf curl virus: No evidence for replication in the insect vector Bemisia tabaci
Authors: Sánchez-Campos Sonia , Rodríguez-Negrete Edgar A. , Cruzado Lucía , Grande-Pérez Ana , Bejarano Eduardo R. , Navas-Castillo Jesús , Moriones Enrique
Published: August 2016

Begomovirus ssDNA plant virus (family Geminiviridae) replication within the Bemisia tabaci vector is controversial. Transovarial transmission, alteration to whitefly biology, or detection of viral transcripts in the vector are proposed as indirect evidence of replication of tomato yellow leaf curl virus (TYLCV). Recently, contrasting direct evidence has been reported regarding the capacity of TYLCV to replicate within individuals of B. tabaci based on quantitave PCR approaches. Time-course experiments to quantify complementary and virion sense viral nucleic acid accumulation within B. tabaci using a recently implemented two step qPCR procedure revealed that viral DNA quantities did not increase for time points up to 96 hours after acquisition of the virus. Our findings do not support a recent report claiming TYLCV replication in individuals of B. tabaci.
iHEART: a miniaturized near-infrared in-line gas sensor using heart-shaped substrate-integrated hollow waveguides
Authors: Ribessi Rafael L. , Neves Thiago de A. , Rohwedder Jarbas J. R. , Pasquini Celio , Raimundo Ivo M. , Wilk Andreas , Kokoric Vjekoslav , Mizaikoff Boris
Published: August 2016

Integration of a heart-shaped substrate-integrated hollow waveguide with a micro-spectrometer results in an ultra-compact gas sensing system: iHEART.
Cheap pencil graphite electrodes for rapid voltammetric determination of chlorogenic acid in dietary supplements
Authors: David I. G. , Popa D. E. , Buleandra M. , Moldovan Z. , Iorgulescu E. E. , Badea I. A.
Published: August 2016

A disposable pencil graphite electrode was used for the first time for rapid voltammetric determination of chlorogenic acid in green coffee dietary supplements.
Flexible perovskite solar cells based on the metal–insulator–semiconductor structure
Authors: Wei Jing , Li Heng , Zhao Yicheng , Zhou Wenke , Fu Rui , Pan Huiyue , Zhao Qing
Published: August 2016

All-low-temperature processed, highly flexible perovskite solar cells based on the MIS structure are fabricated, with ultra-thin Al2O3 as the hole-blocking layer.
N-Hydroxyphthalimide: a new photoredox catalyst for [4+1] radical cyclization of N-methylanilines with isocyanides
Authors: Yadav Arvind K. , Yadav Lal Dhar S.
Published: August 2016

A highly regioselective synthesis of 3-iminodihydroindoles using N-methylanilines and isocyanides at room temperature is described. The protocol utilizes N-hydroxyphthalimide as a new single electron transfer photoredox catalyst.
The first porphyrin–subphthalocyaninatoboron(iii)-fused hybrid with unique conformation and intramolecular charge transfer behavior
Authors: Zhang Yuehong , Oh Juwon , Wang Kang , Shin Dongju , Zhan Xiaopeng , Zheng Yingting , Kim Dongho , Jiang Jianzhuang
Published: August 2016

The first porphyrin–subphthalocyaninatoboron(iii)-fused hybrid with unique conformation and intramolecular charge-transfer behaviour has been isolated and structurally characterized.
Globular–disorder transition in proteins: a compromise between hydrophobic and electrostatic interactions?
Authors: Baruah Anupaul , Biswas Parbati
Published: August 2016

Protein disorder, like protein folding, satisfies the principle of minimal frustration.
Computational prediction and analysis of the 27Al solid-state NMR spectrum of methylaluminoxane (MAO) at variable temperatures and field strengths
Authors: Falls Zackary , Zurek Eva , Autschbach Jochen
Published: August 2016

27Al MAS NMR of the co-catalyst methylaluminoxane may be able to reveal the fraction of species that are catalytically active.
Valence-force model and nanomechanics of single-layer phosphorene
Authors: Midtvedt Daniel , Croy Alexander
Published: August 2016

An improved valence force field model and continuum model for phosphorene enables modeling of macroscopic phosphorene structures.
Empirical in operando analysis of the charge carrier dynamics in hematite photoanodes by PEIS, IMPS and IMVS
Authors: Klotz Dino , Ellis David Shai , Dotan Hen , Rothschild Avner
Published: August 2016

We introduce an empirical in operando analysis of the charge carrier dynamics in hematite photoanodes by PEIS, IMPS and IMVS.
A report on emergent uranyl binding phenomena by an amidoxime phosphonic acid co-polymer
Authors: Abney C. W. , Das S. , Mayes R. T. , Kuo L.-J. , Wood J. , Gill G. , Piechowicz M. , Lin Z. , Lin W. , Dai S.
Published: August 2016

XAFS investigations of uranyl binding by an adsorbent polymer reveal different coordination modes than anticipated from previous small molecule studies.
Small size Mo2C nanocrystal coupled with reduced graphene oxide enhance the electrochemical activity of palladium nanoparticles towards methanol oxidation reaction
Authors: He Chunyong , Tao Juzhou , He Guoqiang , Shen Pei Kang , Qiu Yongfu
Published: August 2016

A small-sized Mo2C nanoparticle on reduced graphene oxide (RGO) nanosheet hybrid (Mo2C–RGO) was applied as a co-catalyst to Pd nanoparticles to form a highly dispersed heterogeneous catalyst (Pd/Mo2C–RGO).
The doubly-bonded ditungsten anion [W2Cp2(μ-PPh2)(NO)2]−: an entry to the chemistry of unsaturated nitrosyl complexes
Authors: Alvarez M. Angeles , García M. Esther , García-Vivó Daniel , Ruiz Miguel A. , Toyos Adrián
Published: August 2016

The title complex, the first anionic nitrosyl complex featuring a metal-metal double bond, displays substantial nucleophilicity, thus providing synthetic access to different unsaturated hydride and heterometallic derivatives, as well as a variety of electron-precise molecules.
P,C-Chelation versus P,P-coordination of unsymmetrical phosphorus ylides in palladacyclopropa[60]fullerene complexes; synthetic, spectroscopic, and theoretical studies
Authors: Sabounchei Seyyed Javad , Hosseinzadeh Marjan , Hashemi Ali , Salehzadeh Sadegh , Maleki Farahnaz
Published: August 2016

New palladacyclopropa[60]fullerene complexes containing P,C-chelated and P,P-coordinated unsymmetrical phosphorus ylides were synthesized and characterized successfully.
Half-sandwich complexes of rhodium containing cysteine-derived ligands
Authors: Carmona María , Rodríguez Ricardo , Lahoz Fernando J. , García-Orduña Pilar , Osante Iñaki , Cativiela Carlos , López José A. , Carmona Daniel
Published: August 2016

Five distinct coordination modes have been disclosed for rhodium complexes containing modified cysteines. From the spectroscopic, theoretical and crystallographic data, the absolute configuration of the compounds has been established.
Competitive coordination aggregation for V-shaped [Co3] and disc-like [Co7] complexes: synthesis, magnetic properties and catechol oxidase activity
Authors: Singha Mahapatra Tufan , Basak Dipmalya , Chand Santanu , Lengyel Jeff , Shatruk Michael , Bertolasi Valerio , Ray Debashis
Published: August 2016

The synthetic procedures, magnetic properties and catecholase-like activity of a V-shaped [CoII3L4] and planar disc-like [CoII7L6] complexes have been discussed.
Vibration-Induced-Emission (VIE) for imaging amyloid β fibrils
Authors: Dou Wei-Tao , Chen Wei , He Xiao-Peng , Su Jianhua , Tian He
Published: August 2016

This paper discusses the use of N,N′-disubstituted-dihydrodibenzo[a,c]phenazines with typical Vibration-Induced-Emission (VIE) properties for imaging amyloid β (Aβ) fibrils, which are a signature of neurological disorders such as Alzheimer's disease. A water-soluble VIEgen with a red fluorescence emission shows a pronounced, blue-shifted emission with Aβ peptide monomers and fibrils. The enhancement in blue fluorescence can be ascribed to the restriction of the molecular vibration by selectively binding to Aβ. We determine an increasing blue-to-red emission ratio of the VIEgen with both the concentration and fibrogenesis time of Aβ, thereby enabling a ratiometric detection of Aβ in its different morphological forms. Importantly, the VIEgen was proven to be suitable for the fluorescence imaging of small Aβ plaques in the hippocampus of a transgenic mouse brain (five months old), with the blue and red emissions well overlapped on the Aβ. This research offers a new rationale to design molecular VIE probes for biological applications.
The glycemic response to fibre rich foods and their relationship with gastric emptying and motor functions: an MRI study
Authors: Gopirajah R. , Raichurkar Keshav Prakash , Wadhwa Rajkumar , Anandharamakrishnan C.
Published: August 2016

The chief motor functions of human stomach, namely receiving, storing, mixing and emptying, influence the absorption of ingested food and hence determine the glycemic response to the meal.
High-throughput acoustic separation of platelets from whole blood
Authors: Chen Yuchao , Wu Mengxi , Ren Liqiang , Liu Jiayang , Whitley Pamela H. , Wang Lin , Huang Tony Jun
Published: August 2016

An acoustic separation device that can achieve high-throughput, high-efficiency, and non-invasive platelet enrichment from undiluted whole blood.
Detailed computational analysis revealed mutation V210I on PrP induced conformational conversion on β2–α2 loop and α2–α3
Authors: Chandrasekaran P. , Rajasekaran R.
Published: August 2016

The development of fatal transmissible spongiform encephalopathies (TSE) is associated with the conformational conversion of the normal cellular prion protein, PrPC, into its pathogenic isoform, PrPSc.
Efficient and stereocontrolled synthesis of chondroitin mono- and disaccharide linked to variously sulfated biotinylated trisaccharides of the linkage region of proteoglycans
Authors: Aït-Mohand Katia , Mirault Anaïs , Jacquinet Jean-Claude , Lopin-Bon Chrystel
Published: August 2016

Various sulfated biotinylated tetra- and pentasaccharides having the backbone of partial linkage region plus chondroitin sulfate unit have been synthesized.
Synthesis of substituted benzooxaborinin-1-ols via palladium-catalysed cyclisation of alkenyl- and alkynyl-boronic acids
Authors: Benhamou Laure , Walker Daniel W. , Bučar Dejan-Krešimir , Aliev Abil E. , Sheppard Tom D.
Published: August 2016

Substituted benzooxaborinin-1-ols can be preparedviapalladium-catalysed oxidative cyclisation of boronic acids bearing a pendent alkene or alkyne group.
The synthesis of a pyridine-N-oxide isophthalamide rotaxane utilizing supplementary amide hydrogen bond interactions
Authors: Evans Nicholas H. , Gell Charles E. , Peach Michael J. G.
Published: August 2016

A pyridine-N-oxide containing rotaxane has been prepared in 32% yield. The role of macrocycle structure in successful pseudo-rotaxane formation has been rationalised by a combination of NMR spectroscopy, X-ray crystallography and computational modelling.
A delayed curing ROMP based thermosetting resin
Authors: Baumgartner Ryan , Ryba Konrad , Song Ziyuan , Wang Ruibo , Harris Keith , Katz Joshua S. , Cheng Jianjun
Published: August 2016

A liquid ROMP based thermosetting resin is developed which undergoes slow polymerization at room temperature and rapid polymerization at elevated temperatures.
A scratch resistant yet healable automotive clearcoat containing hyperbranched polymer and POSS nanostructures
Authors: Yari H. , Mohseni M. , Messori M.
Published: August 2016

In this paper a typical acrylic melamine clearcoat has been modified with hyperbranched polymer and polyhedral oligomeric silsesquioxane nanostructures to simultaneously enhance its scratch resistance and healing ability.
Biomolecule-assisted solvothermal synthesis of Cu2SnS3 flowers/RGO nanocomposites and their visible-light-driven photocatalytic activities
Authors: Vadivel S. , Maruthamani D. , Paul Bappi , Dhar Siddhartha Sankar , Habibi-Yangjeh A. , Balachandran S. , Saravanakumar B. , Selvakumar A. , Selvam K.
Published: August 2016

Elimination of organic pollutants from wastewaters under visible-light irradiation is a venerable challenge in the fields of environmental and material science.
One-step deposition of a melanin-like polymer on individual Escherichia coli cells exhibiting a special UV resistance effect
Authors: Zhang Bai , Sun Zhou , Bai Yuting , Zhuang Hanqiong , Ge Dongtao , Shi Wei , Sun Yanan
Published: August 2016

Melanin-like polydopamine encapsulatedE. colicells could retained cells viability, inhibited cell division and protected cells from UV radiation. These provide both fundamental research and applications of cell encapsulation for UV resistance.
Aggregation–disaggregation pattern of photodynamically active ZnPcS4 and its interaction with DNA alkylating quinone: effect of micellar compactness and central metal ion
Authors: Jadhao Manojkumar , Mukherjee Soham , Joshi Ritika , Kumar Himank , Ghosh Sujit Kumar
Published: August 2016

The graphical abstract shows the aggregation–disaggregation pattern of ZnPcS4 in neutral and different cationic micelles and its enhanced interaction with a DNA alkylating quinone in a TTAB micellar medium.
Flash μ-fluidics: a rapid prototyping method for fabricating microfluidic devices
Authors: Buttner U. , Sivashankar S. , Agambayev S. , Mashraei Y. , Salama K. N.
Published: August 2016

We demonstrate a fast and economically viable 2D/3D maskless digital light-projection based on stereolithography compared to traditional processes. Furthermore, electrodes and sensors are easily integrated without introducing leakages to the LOC.
Morphology effect of polythiophene catalysts on photo-degradation of methylene blue
Authors: Yu Yue , Jin Jiancheng , Yu Xi , Xiao Xiangheng , Hong Xinlin
Published: August 2016

Polythiophene with different morphologies have different photo-catalytic activities to degrade methylene blue.
Design and assembly of an aqueous red CdTe QD-LED: major factors to fabricate aqueous QD-LEDs
Authors: Du Jinhua , Xu Shuhong , Wang Chunlei , Pan Jiangyong , Chen Jing , Zhu Li , Lv Changgui , Cui Yiping
Published: August 2016

The aqueous red CdTe QD-LED with structure of ITO/PEDOT:PSS/PVK/CdTe QDs/ZnO/Al. Two major factors to fabricate an aqueous QD-LED successfully are adding wet agent to the QDs solution and removing the composite ions remaining in the QDs solution.
Assembly of porous NiO nanowires on carbon cloth as a flexible electrode for high-performance supercapacitors
Authors: Peng Yi-Hang , Guo Mei-Xia , Shao Fu , Liu Si , Zhu Quan , Bian Shao-Wei
Published: August 2016

Porous NiO nanowire layers were deposited on conductive carbon cloth and are used as flexible electrodes for high performance supercapacitors.
Facile synthesis of carbon–NiCoO2 composite microspheres with pitaya-type structure and their application in supercapacitors
Authors: Ma Yongchao , Liu Ping , Liu Qingzhi , Chen Zhiwei , Qu Dan , Shi Jinsheng
Published: August 2016

Three-dimensional carbon–NiCoO2 microspheres were prepared. NiCoO2 nanoparticles were inserted into porous carbon microspheres. The composite showed high specific capacity and stable capacity retention.
Keplerate-type polyoxometalate/semiconductor composite electrodes with light-enhanced conductivity towards highly efficient photoelectronic devices
Authors: Xu Shasha , Wang Yanhua , Zhao Yue , Chen Weilin , Wang Jiabo , He Lifei , Su Zhongmin , Wang Enbo , Kang Zhenhui
Published: August 2016

We designed and fabricated POM/MOS composite photoelectrodes with light-enhanced conductivity. {Mo132} clusters act as a photo-induced electron acceptor/donor.
Sulfur and nitrogen co-doped hollow carbon spheres for sodium-ion batteries with superior cyclic and rate performance
Authors: Ye Jianchuan , Zang Jun , Tian Zhaowu , Zheng Mingsen , Dong Quanfeng
Published: August 2016

A facile way to prepare S, N-co-doped hollow carbon spheres with excellent cyclic and rate performance for sodium ion batteries.
Interfacial engineering with amino-functionalized graphene for efficient perovskite solar cells
Authors: Wen Xiaoru , Wu Jiamin , Gao Di , Lin Changjian
Published: August 2016

In pursuit of reducing the surface trap states of perovskite as well as enhancing the hole control of dopant-free spiro-OMeTAD, an amino-rich graphene (NGs) was introduced via a facial solution method as an interlayer at the perovskite/HTM interface.
Performance analysis of a low‐complexity MAP algorithm for automatic modulation classification in adaptive OFDM systems
Authors: Bahrani Sima , Derakhtian Mostafa , Zolghadrasli Alireza
Published: August 2016

Automatic modulation classification (AMC) techniques enable the estimation of the bit allocation table in adaptive orthogonal frequency division multiplexing (OFDM) systems. In this study, the authors investigate the classification performance of a low‐complexity maximum‐a‐posteriori (MAP) algorithm for AMC. Also, they derive an approximation of the probability of classification error in a subcarrier for this classifier. Furthermore, based on these theoretical derivations, a novel modified rate adaptive (RA) bit loading algorithm with additional classification error constraint is proposed. Numerical results show that the authors’ proposed method outperforms the RA algorithm significantly in terms of classification performance, while providing reasonable data throughput specifically at higher signal‐to‐noise ratios.
Fault‐tolerant control for descriptor stochastic systems with extended sliding mode observer approach
Authors: Yu Jinyong , Sun Yiyong , Lin Weiyang , Li Zhan
Published: August 2016

This study concentrates on the fault‐tolerant control and fault estimation problems for a class of descriptor stochastic systems with state‐dependent faults. A new extended observer method is presented to solve these design problems. First, the descriptor stochastic system is transformed into a non‐singular system, and an augmented system is constructed by assembling the fault states into the augmented vector. Then, a novel sliding mode observer with two discontinuous input terms is designed to estimate the states and faults of system. A state‐feedback control scheme based on the state estimates is synthesised to guarantee the closed‐loop systems stable. Finally, a numerical example is presented to show the effectiveness of the proposed design approach.
A deterministic alternative to the full configuration interaction quantum Monte Carlo method
Authors: Tubman Norm M. , Lee Joonho , Takeshita Tyler Y. , Head-Gordon Martin , Whaley K. Birgitta
Published: August 2016

Development of exponentially scaling methods has seen great progress in tackling larger systems than previously thought possible. One such technique, full configuration interaction quantum Monte Carlo, is a useful algorithm that allows exact diagonalization through stochastically sampling determinants. The method derives its utility from the information in the matrix elements of the Hamiltonian, along with a stochastic projected wave function, to find the important parts of Hilbert space. However, the stochastic representation of the wave function is not required to search Hilbert space efficiently, and here we describe a highly efficient deterministic method that can achieve chemical accuracy for a wide range of systems, including the difficult Cr2 molecule. We demonstrate for systems like Cr2 that such calculations can be performed in just a few cpu hours which makes it one of the most efficient and accurate methods that can attain chemical accuracy for strongly correlated systems. In addition our method also allows efficient calculation of excited state energies, which we illustrate with benchmark results for the excited states of C2.
A density functional theory study of the adsorption behaviour of CO2 on Cu2O surfaces
Authors: Mishra Abhishek Kumar , Roldan Alberto , de Leeuw Nora H.
Published: August 2016

Copper has many applications, particularly in electro-catalysis, where the oxidation state of the copper electrode plays a significant role in the selectivity towards products. Although copper-based materials have clear potential as catalysts in the reduction of CO2 and conversion to products, fundamental understanding of CO2 adsorption and activation on different copper oxide surfaces is still limited. We have used DFT+U methodology to study the surface reconstruction of the three most exposed (111), (110), and (001) surfaces of Cu2O with different possible terminations. Considering several adsorbate geometries, we have investigated CO2 adsorption on five different possible terminations and proposed eight different configurations in which CO2 binds with the surface. Similar to earlier findings, CO2 binds weakly with the most stable Cu2O(111):O surface showing no molecular activation, whereas a number of other surfaces, which can appear in the Cu2O particles morphology, show stronger binding as well as activation of the CO2 molecule. Different CO2 coverages were studied and a detailed structural and electronic charge analysis is presented. The activation of the CO2 molecule is characterized by structural transformations and charge transfer between the surface and the CO2 molecule, which is further confirmed by considerable red shifts in the vibrational frequencies.
Influence of surface vacancy defects on the carburisation of Fe 110 surface by carbon monoxide
Authors: Chakrabarty Aurab , Bouhali Othmane , Mousseau Normand , Becquart Charlotte S. , El-Mellouhi Fedwa
Published: August 2016

Adsorption and dissociation of gaseous carbon monoxide (CO) on metal surfaces is one of the most frequently occurring processes of carburisation, known as primary initiator of metal dusting corrosion. Among the various factors that can significantly influence the carburisation process are the intrinsic surface defects such as single surface vacancies occurring at high concentrations due to their low formation energy. Intuitively, adsorption and dissociation barriers of CO are expected to be lowered in the vicinity of a surface vacancy, due to the strong attractive interaction between the vacancy and the C atom. Here the adsorption energies and dissociation pathways of CO on clean and defective Fe 110 surface are explored by means of density functional theory. Interestingly, we find that the O adatom, resulting from the CO dissociation, is unstable in the electron-deficit neighbourhood of the vacancy due to its large electron affinity, and raises the barrier of the carburisation pathway. Still, a full comparative study between the clean surface and the vacancy-defected surface reveals that the complete process of carburisation, starting from adsorption to subsurface diffusion of C, is more favourable in the vicinity of a vacancy defect.
Nanoindentation of the pristine and irradiated forms of a sodium borosilicate glass: Insights from molecular dynamics simulations
Authors: Kilymis D. A. , Delaye J.-M. , Ispas S.
Published: August 2016

We have carried out classical molecular dynamics simulations in order to get insight into the atomistic mechanisms of the deformation during nanoindentation of the pristine and irradiated forms of a sodium borosilicate glass. In terms of the glass hardness, we have found that the primary factor affecting the decrease of hardness after irradiation is depolymerization rather than free volume, and we argue that this is a general trend applicable to other borosilicate glasses with similar compositions. We have analyzed the changes of the short- and medium-range structures under deformation and found that the creation of oxygen triclusters is an important mechanism in order to describe the deformation of highly polymerized borosilicate glasses and is essential in the understanding of the folding of large rings under stress. We have equally found that the less polymerized glasses present a higher amount of relative densification, while the analysis of bond-breaking during the nanoindentation has showed that shear flow is more likely to appear around sodium atoms. The results provided in this study can be proven to be useful in the interpretation of experimental results.
Nucleation in food colloids
Authors: Povey Malcolm J. W.
Published: August 2016

Nucleation in food colloids has been studied in detail using ultrasound spectroscopy. Our data show that classical nucleation theory (CNT) remains a sound basis from which to understand nucleation in food colloids and analogous model systems using n-alkanes. Various interpretations and modifications of CNT are discussed with regard to their relevance to food colloids. Much of the evidence presented is based on the ultrasound velocity spectrometry measurements which has many advantages for the study of nucleating systems compared to light scattering and NMR due to its sensitivity at low solid contents and its ability to measure true solid contents in the nucleation and early crystal growth stages. Ultrasound attenuation spectroscopy also responds to critical fluctuations in the induction region. We show, however, that a periodic pressure fluctuation such as a quasi-continuous (as opposed to a pulse comprising only a few pressure cycles) ultrasound field can alter the nucleation process, even at very low acoustic intensity. Thus care must be taken when using ultrasound techniques that the measurements do not alter the studied processes. Quasi-continuous ultrasound fields may enhance or suppress nucleation and the criteria to determine such effects are derived. The conclusions of this paper are relevant to colloidal systems in foods, pharmaceuticals, agro-chemicals, cosmetics, and personal products.
Analytic second derivative of the energy for density-functional tight-binding combined with the fragment molecular orbital method
Authors: Nakata Hiroya , Nishimoto Yoshio , Fedorov Dmitri G.
Published: August 2016

The analytic second derivative of the energy is developed for the fragment molecular orbital (FMO) method combined with density-functional tight-binding (DFTB), enabling simulations of infrared and Raman spectra of large molecular systems. The accuracy of the method is established in comparison to full DFTB without fragmentation for a set of representative systems. The performance of the FMO-DFTB Hessian is discussed for molecular systems containing up to 10 041 atoms. The method is applied to the study of the binding of α-cyclodextrin to polyethylene glycol, and the calculated IR spectrum of an epoxy amine oligomer reproduces experiment reasonably well.
Measurement of effect of electron cyclotron heating in a tandem mirror plasma using a semiconductor detector array and an electrostatic energy analyzer
Authors: Minami R. , Imai T. , Kariya T. , Numakura T. , Uehara M. , Tsumura K. , Ebashi Y. , Kajino S. , Endo Y. , Nakashima Y.
Published: August 2016

Temporally and spatially resolved soft x-ray and end-loss-electron analyses of the electron cyclotron heated plasmas are carried out by using a semiconductor detector array and an electrostatic energy analyzer in the GAMMA 10 tandem mirror. The flux and the energy spectrum of the end loss electrons are measured by a multi-grid energy analyzer. Recently, the electron cyclotron heating power modulation experiments have been started in order to generate and control the high heat flux and to make the edge localized mode-like intermittent heat load pattern for the divertor simulation studies by the use of these detectors for electron properties.
Left-right correlation in coupled F-center defects
Authors: Janesko Benjamin G.
Published: August 2016

This work explores how left-right correlation, a textbook problem in electronic structure theory, manifests in a textbook example of electrons trapped in crystal defects. I show that adjacent F-center defects in lithium fluoride display symptoms of “strong” left-right correlation, symptoms similar to those seen in stretched H2. Simulations of UV/visible absorption spectra qualitatively fail to reproduce experiment unless left-right correlation is taken into account. This is of interest to both the electronic structure theory and crystal-defect communities. Theorists have a new well-behaved system to test their methods. Crystal-defect groups are cautioned that the approximations that successfully model single F-centers may fail for adjacent F-centers.
Polarimeter for the General Fusion SPECTOR machine
Authors: Carle Patrick , Froese Aaron , Wong Adrian , Howard Stephen , O’Shea Peter , Laberge Michel
Published: August 2016

A polarimeter has been designed to measure Faraday rotation and help to understand the profile of its safety factor, q, on the recently built SPECTOR magnetized target fusion machine at General Fusion. The polarimeter uses two counter-rotating, circularly polarized, 118.8 μm beams to probe the plasma. Grad-Shafranov simulations have been used to investigate the effect of measurement error and chord geometry.
Dynamic magnetic hysteresis and nonlinear susceptibility of antiferromagnetic nanoparticles
Authors: Kalmykov Yuri P. , Ouari Bachir , Titov Serguey V.
Published: August 2016

The nonlinear ac stationary response of antiferromagnetic nanoparticles subjected to both external ac and dc fields of arbitrary strength and orientation is investigated using Brown's continuous diffusion model. The nonlinear complex susceptibility and dynamic magnetic hysteresis (DMH) loops of an individual antiferromagnetic nanoparticle are evaluated and compared with the linear regime for extensive ranges of the anisotropy, the ac and dc magnetic fields, damping, and the specific antiferromagnetic parameter. It is shown that the shape and area of the DMH loops of antiferromagnetic particles are substantially altered by applying a dc field that permits tuning of the specific magnetic power loss in the nanoparticles.
Polarized Raman backscattering selection rules for (hhl)-oriented diamond- and zincblende-type crystals
Authors: Steele J. A. , Puech P. , Lewis R. A.
Published: August 2016

Due to their interesting orientation-dependent properties, the ability to grow high-index semiconductor crystals and nanostructures extends the design palette for applications based on these materials. Notably, a source containing a systematic reporting of what the Raman tensors are for an arbitrary high-index zincblende material is yet to appear in the literature. Herein, we present the polarized Raman backscattering selection rules for arbitrary (hhl)-oriented diamond- and zincblende-type crystal surfaces and verify their correctness through experiment (up to (115)). Considering the many degrees of freedom available to common polarized micro-Raman scattering instruments, and the unique local orientation of the probed material, we further examine a range of consequences imposed by the selection rules for the Raman backscattering method.
Upgraded millimeter-wave interferometer for measuring the electron density during the beam extraction in the negative ion source
Authors: Tokuzawa T. , Kisaki M. , Nagaoka K. , Tsumori K. , Ito Y. , Ikeda K. , Nakano H. , Osakabe M. , Takeiri Y. , Kaneko O.
Published: August 2016

The upgraded millimeter-wave interferometer with the frequency of 70 GHz is installed on a large-scaled negative ion source. Measurable line-averaged electron density is from 2 × 1015 to 3 × 1018 m−3 in front of the plasma grid. Several improvements such as the change to shorter wavelength probing with low noise, the installation of special ordered horn antenna, the signal modulation for a high accuracy digital phase detection, the insertion of insulator, and so on, are carried out for the measurement during the beam extraction by applying high voltage. The line-averaged electron density is successfully measured and it is found that it increases linearly with the arc power and drops suddenly at the beam extraction.
The cell-stretcher: A novel device for the mechanical stimulation of cell populations
Authors: Seriani S. , Del Favero G. , Mahaffey J. , Marko D. , Gallina P. , Long C. S. , Mestroni L. , Sbaizero O.
Published: August 2016

Mechanical stimulation appears to be a critical modulator for many aspects of biology, both of living tissue and cells. The cell-stretcher, a novel device for the mechanical uniaxial stimulation of populations of cells, is described. The system is based on a variable stroke cam-lever-tappet mechanism which allows the delivery of cyclic stimuli with frequencies of up to 10 Hz and deformation between 1% and 20%. The kinematics is presented and a simulation of the dynamics of the system is shown, in order to compute the contact forces in the mechanism. The cells, following cultivation and preparation, are plated on an ad hoc polydimethylsiloxane membrane which is then loaded on the clamps of the cell-stretcher via force-adjustable magnetic couplings. In order to show the viability of the experimentation and biocompatibility of the cell-stretcher, a set of two in vitro tests were performed. Human epithelial carcinoma cell line A431 and Adult Mouse Ventricular Fibroblasts (AMVFs) from a dual reporter mouse were subject to 0.5 Hz, 24 h cyclic stretching at 15% strain, and to 48 h stimulation at 0.5 Hz and 15% strain, respectively. Visual analysis was performed on A431, showing definite morphological changes in the form of cellular extroflections in the direction of stimulation compared to an unstimulated control. A cytometric analysis was performed on the AMVF population. Results show a post-stimulation live-dead ratio deviance of less than 6% compared to control, which proves that the environment created by the cell-stretcher is suitable for in vitro experimentation.
Dynamic measurements and simulations of airborne picolitre-droplet coalescence in holographic optical tweezers
Authors: Bzdek Bryan R. , Collard Liam , Sprittles James E. , Hudson Andrew J. , Reid Jonathan P.
Published: August 2016

We report studies of the coalescence of pairs of picolitre aerosol droplets manipulated with holographic optical tweezers, probing the shape relaxation dynamics following coalescence by simultaneously monitoring the intensity of elastic backscattered light (EBL) from the trapping laser beam (time resolution on the order of 100 ns) while recording high frame rate camera images (time resolution <10 μs). The goals of this work are to: resolve the dynamics of droplet coalescence in holographic optical traps; assign the origin of key features in the time-dependent EBL intensity; and validate the use of the EBL alone to precisely determine droplet surface tension and viscosity. For low viscosity droplets, two sequential processes are evident: binary coalescence first results from the overlap of the optical traps on the time scale of microseconds followed by the recapture of the composite droplet in an optical trap on the time scale of milliseconds. As droplet viscosity increases, the relaxation in droplet shape eventually occurs on the same time scale as recapture, resulting in a convoluted evolution of the EBL intensity that inhibits quantitative determination of the relaxation time scale. Droplet coalescence was simulated using a computational framework to validate both experimental approaches. The results indicate that time-dependent monitoring of droplet shape from the EBL intensity allows for robust determination of properties such as surface tension and viscosity. Finally, the potential of high frame rate imaging to examine the coalescence of dissimilar viscosity droplets is discussed.
Calculations of oxide formation on low-index Cu surfaces
Authors: Lian Xin , Xiao Penghao , Yang Sheng-Che , Liu Renlong , Henkelman Graeme
Published: August 2016

Density-functional theory is used to evaluate the mechanism of copper surface oxidation. Reaction pathways of O2 dissociation on the surface and oxidation of the sub-surface are found on the Cu(100), Cu(110), and Cu(111) facets. At low oxygen coverage, all three surfaces dissociate O2 spontaneously. As oxygen accumulates on the surfaces, O2 dissociation becomes more difficult. A bottleneck to further oxidation occurs when the surfaces are saturated with oxygen. The barriers for O2 dissociation on the O-saturated Cu(100)-c(2×2)-0.5 monolayer (ML) and Cu(100) missing-row structures are 0.97 eV and 0.75 eV, respectively; significantly lower than those have been reported previously. Oxidation of Cu(110)-c(6×2), the most stable (110) surface oxide, has a barrier of 0.72 eV. As the reconstructions grow from step edges, clean Cu(110) surfaces can dissociatively adsorb oxygen until the surface Cu atoms are saturated. After slight rearrangements, these surface areas form a “1 ML” oxide structure which has not been reported in the literature. The barrier for further oxidation of this “1 ML” phase is only 0.31 eV. Finally the oxidized Cu(111) surface has a relatively low reaction energy barrier for O2 dissociation, even at high oxygen coverage, and allows for facile oxidation of the subsurface by fast O diffusion through the surface oxide. The kinetic mechanisms found provide a qualitative explanation of the observed oxidation of the low-index Cu surfaces.
Patterning monolayer graphene with zigzag edges on hexagonal boron nitride by anisotropic etching
Authors: Wang Guole , Wu Shuang , Zhang Tingting , Chen Peng , Lu Xiaobo , Wang Shuopei , Wang Duoming , Watanabe Kenji , Taniguchi Takashi , Shi Dongxia , Yang Rong , Zhang Guangyu
Published: August 2016

Graphene nanostructures are potential building blocks for nanoelectronic and spintronic devices. However, the production of monolayer graphene nanostructures with well-defined zigzag edges remains a challenge. In this paper, we report the patterning of monolayer graphene nanostructures with zigzag edges on hexagonal boron nitride (h-BN) substrates by an anisotropic etching technique. We found that hydrogen plasma etching of monolayer graphene on h-BN is highly anisotropic due to the inert and ultra-flat nature of the h-BN surface, resulting in zigzag edge formation. The as-fabricated zigzag-edged monolayer graphene nanoribbons (Z-GNRs) with widths below 30 nm show high carrier mobility and width-dependent energy gaps at liquid helium temperature. These high quality Z-GNRs are thus ideal structures for exploring their valleytronic or spintronic properties.
Asymmetric band offsets in silicon heterojunction solar cells: Impact on device performance
Authors: Seif Johannes Peter , Menda Deneb , Descoeudres Antoine , Barraud Loris , Özdemir Orhan , Ballif Christophe , De Wolf Stefaan
Published: August 2016

Amorphous/crystalline silicon interfaces feature considerably larger valence than conduction band offsets. In this article, we analyze the impact of such band offset asymmetry on the performance of silicon heterojunction solar cells. To this end, we use silicon suboxides as passivation layers—inserted between substrate and (front or rear) contacts—since such layers enable intentionally exacerbated band-offset asymmetry. Investigating all topologically possible passivation layer permutations and focussing on light and dark current-voltage characteristics, we confirm that to avoid fill factor losses, wider-bandgap silicon oxide films (of at least several nanometer thin) should be avoided in hole-collecting contacts. As a consequence, device implementation of such films as window layers—without degraded carrier collection—demands electron collection at the front and hole collection at the rear. Furthermore, at elevated operating temperatures, once possible carrier transport barriers are overcome by thermionic (field) emission, the device performance is mainly dictated by the passivation of its surfaces. In this context, compared to the standard amorphous silicon layers, the wide-bandgap oxide layers applied here passivate remarkably better at these temperatures, which may represent an additional benefit under practical operation conditions.
Enhanced magnetic field probe array for improved excluded flux calculations on the C-2U advanced beam-driven field-reversed configuration plasma experiment
Authors: Roche T. , Thompson M. C. , Mendoza R. , Allfrey I. , Garate E. , Romero J. , Douglass J.
Published: August 2016

External flux conserving coils were installed onto the exterior of the C-2U [M. W. Binderbauer et al., Phys. Plasmas 22, 056110 (2015)] confinement vessel to increase the flux confinement time of the system. The 0.5 in. stainless steel vessel wall has a skin time of ∼5 ms. The addition of the external copper coils effectively increases this time to ∼7 ms. This led to better-confined/longer-lived field-reversed configuration (FRC) plasmas. The fringing fields generated by the external coils have the side effect of rendering external field measurements invalid. Such measurements were key to the previous method of excluded flux calculation [M. C. Thompson et al., Rev. Sci. Instrum. 83, 10D709 (2012)]. A new array of B-dot probes and Rogowski coils were installed to better determine the amount of flux leaked out of the system and ultimately provide a more robust measurement of plasma parameters related to pressure balance including the excluded flux radius. The B-dot probes are surface mountable chip inductors with inductance of 33 μH capable of measuring the DC magnetic field and transient field, due to resistive current decay in the wall/coils, when coupled with active integrators. The Rogowski coils measure the total change in current in each external coil (150 A/2 ms). Currents were also actively driven in the external coils. This renders the assumption of total flux conservation invalid which further complicates the analysis process. The ultimate solution to these issues and the record breaking resultant FRC lifetimes will be presented.
Note: Laser wavelength precision measurement based on a laser synthetic wavelength interferometer
Authors: Yan Liping , Chen Benyong , Zhang Shihua , Liu Pengpeng , Zhang Enzheng
Published: August 2016

A laser wavelength precision measurement method is presented based on the laser synthetic wavelength interferometer (LSWI). According to the linear relation between the displacements of measurement and reference arms in the interferometer, the synthetic wavelength produced by an unknown wavelength and a reference wavelength can be measured by detecting the phase coincidences of two interference signals. The advantage of the method is that a larger synthetic wavelength resulting from an unknown wavelength very close to the reference wavelength can be easily determined according to the linear relation in the interferometer. Then the unknown wavelength is derived according to the one-to-one corresponding relationship between single wavelength and synthetic wavelength. Wavelengths of an external cavity diode laser and two He-Ne lasers were determined experimentally. The experimental results show that the proposed method is able to realize a relative uncertainty on the order of 10−8.
Research Update: The electronic structure of hybrid perovskite layers and their energetic alignment in devices
Authors: Olthof Selina
Published: August 2016

In recent years, the interest in hybrid organic–inorganic perovskites has increased at a rapid pace due to their tremendous success in the field of thin film solar cells. This area closely ties together fundamental solid state research and device application, as it is necessary to understand the basic material properties to optimize the performances and open up new areas of application. In this regard, the energy levels and their respective alignment with adjacent charge transport layers play a crucial role. Currently, we are lacking a detailed understanding about the electronic structure and are struggling to understand what influences the alignment, how it varies, or how it can be intentionally modified. This research update aims at giving an overview over recent results regarding measurements of the electronic structure of hybrid perovskites using photoelectron spectroscopy to summarize the present status.
Magnetically tunable unidirectional waveguide based on magnetic photonic crystals
Authors: Tong Weiwei , Wang Jiafu , Wang Jun , Liu Zhaotang , Pang Yongqiang , Qu Shaobo
Published: August 2016

In this letter, we presented a magnetically tunable ferrite-loaded unidirectional waveguide based on magnetic photonic crystals. Two rows of ferrite rods are symmetrically arranged near the two lateral sides of the rectangular waveguide, where they are biased with static magnetic fields with the same amplitude and opposite directions along the rod axis. Since the magnetic one-way transmission is induced by the magnetic surface plasmon resonance, the operating band of the unidirectional waveguide can be tuned by changing the biased magnetic field intensity. To validate the design, a prototype was fabricated and measured. Both the simulation and experiment results verify the unidirectional transmission property.
HAMR media based on exchange bias
Authors: Elphick K. , Vallejo-Fernandez G. , Klemmer T. J. , Thiele J.-U. , O'Grady K.
Published: August 2016

In this work, we describe an alternative strategy for the development of heat assisted magnetic recording media. In our approach, the need for a storage material with a temperature dependent anisotropy and to provide a read out signal is separated so that each function can be optimised independently. This is achieved by the use of an exchange bias structure where a conventional CoCrPt-SiO2 recording layer is exchange biased to an underlayer of IrMn such that heating and cooling in the exchange field from the recording layer results in a shifted loop. This strategy requires the reorientation of the IrMn layer to allow coupling to the recording layer. This has been achieved by the use of an ultrathin (0.8 nm) layer of Co deposited beneath the IrMn layer. In this system, the information is in effect stored in the antiferromagnetic layer, and hence, there is no demagnetising field generated by the stored bits. A loop shift of 688 Oe has been achieved where both values of coercivity lie to one side of the origin and the information cannot be erased by a magnetic field.