bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of alkali metal cations in the stabilization of guanine quadruplexes: why K+ is the best
Authors: Zaccaria F. , Paragi G. , Fonseca Guerra C.
Published: May 2016

The desolvation and size of monovalent alkali metal ions are of equal importance for the cation affinity of guanine quadruplexes.
Synthesis, photophysical, electrochemical and electrochemiluminescence properties of A2B2 zinc porphyrins: the effect of π-extended conjugation
Authors: Galván-Miranda Elizabeth K. , Castro-Cruz Hiram M. , Arturo Arias-Orea J. , Iurlo Matteo , Valenti Giovanni , Marcaccio Massimo , Macías-Ruvalcaba Norma A.
Published: May 2016

Electrogenerated chemiluminescence of A2B2 porphyrins: the effect of extended conjugation.
Correction: On the stability of manganese tris(β-diketonate) complexes as redox mediators in DSSCs
Authors: Carli Stefano , Benazzi Elisabetta , Casarin Laura , Bernardi Tatiana , Bertolasi Valerio , Argazzi Roberto , Caramori Stefano , Bignozzi Carlo Alberto
Published: May 2016

Correction for ‘On the stability of manganese tris(β-diketonate) complexes as redox mediators in DSSCs' by Stefano Carli et al., Phys. Chem. Chem. Phys., 2016, 18, 5949–5956.
Heteroleptic Ir(iii) and Pt(ii) complexes based on 2-(2,4-difluorophenyl)-pyridine and bisthienylethene BrLH: the influence of the metal center on structures, luminescence and photochromism
Authors: Gong Dan-Ping , Cao Deng-Ke
Published: May 2016

Based on bisthienylethene BrLH, [Ir(dfppy)2(BrL)]·3CH3OH (1) and [Pt(dfppy)(BrL)]·CH3OH (2) have been prepared. The two complexes are significantly different in structure, luminescence and photochromic behavior, due to their different metal centers.
Statistical generation of training sets for measuring NO3−, NH4+and major ions in natural waters using an ion selective electrode array
Authors: Mueller Amy V. , Hemond Harold F.
Published: May 2016

Knowledge of the statistics of environmental systems combined with novel signal processing can significantly improve the utility of existing sensors forin situmeasurements of key nutrients.
Mechanisms of CO2capture in ionic liquids: a computational perspective
Authors: Mercy Maxime , de Leeuw Nora H. , Bell Robert G.
Published: May 2016

We present computational studies of CO2sorption in two different classes of ionic liquid. The addition of carbon dioxide to four superbase ionic liquids, [P3333][Benzim], [P3333][124Triz], [P3333][123Triz] and [P3333][Bentriz], was studied using the DFT approach and considering anions alone and individual ion pairs. The addition of CO2to the anion alone clearly resulted in the formation of a covalently-bound carbamate function with the strength of binding correlated to experimental capacity. In the ion pair however the cation significantly alters the nature of the bonding such that the overall cohesive energy is reduced. Formation of a strong carbamate function occurs at the expense of weakening the interaction between anion and cation. In [N1111][l-ALA], a representative amino acid ionic liquid, evidence was found for a low-energy monomolecular mechanism for carbamate formation, explaining the 1 : 1 molar uptake ratio observed in some amino acid ionic liquids. The mechanism involves proton transfer to the carboxylate group of the aminate anion.
Eosin Y catalyzed difunctionalization of styrenes using O2 and CS2: a direct access to 1,3-oxathiolane-2-thiones
Authors: Yadav Arvind K. , Yadav Lal Dhar S.
Published: May 2016

An efficient, one-pot, highly regioselective synthesis of 1,3-oxathiolane-2-thiones from styrenes, CS2, atmospheric O2 and visible light is reported.
Droplet-based magnetic bead immunoassay using microchannel-connected multiwell plates (μCHAMPs) for the detection of amyloid beta oligomers
Authors: Park Min Cheol , Kim Moojong , Lim Gun Taek , Kang Sung Min , An Seong Soo A , Kim Tae Song , Kang Ji Yoon
Published: May 2016

Automated operation of droplet-based magnetic bead immunoassay in the μCHAMPs.
Anthra- and pentacenequinone derivatives: influence of structure on the formation of columnar liquid crystal phases
Authors: Paquette Joseph A. , Yardley Rebecca E. , Yu Joanne Wing-Yan , Eichhorn S. Holger , Maly Kenneth E.
Published: May 2016

The mesomorphic properties of novel acenequinones reveals that a perpendicular packing motif is an important factor for determining mesophase stability.
Large-area high-quality graphene on Ge(001)/Si(001) substrates
Authors: Pasternak I. , Dabrowski P. , Ciepielewski P. , Kolkovsky V. , Klusek Z. , Baranowski J. M. , Strupinski W.
Published: May 2016

Various experimental data revealing large-area high-quality graphene films grown by the CVD method on Ge(001)/Si(001) substrates are presented.
Preparation and characterization of long chain branched polycarbonates with significantly enhanced environmental stress cracking behavior through gamma radiation with addition of difunctional monomer
Authors: Han Xiaohang , Hu Yangguang , Tang Miao , Fang Huagao , Wu Qianghua , Wang Zhigang
Published: May 2016

A series of long chain branched polycarbonates (LCB-PCs) was prepared with unique topological structures and significantly enhanced ESC properties.
Unanticipated bright blue fluorescence produced from novel hyperbranched polysiloxanes carrying unconjugated carbon–carbon double bonds and hydroxyl groups
Authors: Niu Song , Yan Hongxia , Chen Zhengyan , Li Song , Xu Peilun , Zhi Xiaoli
Published: May 2016

Bright blue fluorescence-emitting hyperbranched polysiloxane simultaneously carrying unconjugated carbon–carbon double bonds and hydroxyl groups is reported for the first time.
Tunable room temperature magnetoelectric response of SmFeO3/poly(vinylidene fluoride) nanocomposite films
Authors: Ahlawat Anju , Satapathy Srinibas , Choudhary Ram J. , Shirolkar Mandar M. , Singh Mrigendra K. , Gupta Pradeep K.
Published: May 2016

SmFeO3/poly(vinylidene fluoride) composite films exhibit tunable magnetoelectric effects induced by strong strain interactions at the interfaces.
The morphologies and optical properties of three-dimensional GaN nano-cone arrays
Authors: Wang Haotian , Zhai Guangmei , Shang Lin , Ma Shufang , Jia Wei , Jia Zhigang , Liang Jian , Li Xuemin , Xu Bingshe
Published: May 2016

Three-dimensional GaN nanostructures with well-aligned nano-cones were fabricated via laser interference lithography + inductively coupled plasma etching techniques.
Organic–inorganic hybrid cathodes: facile synthesis of polypyrrole/zinc oxide nanofibers for low turn-on electron field emitters
Authors: Rawal Ishpal , Carey J. David , Panwar O. S. , Tripathi Ravi Kant
Published: May 2016

Hybrid organic–inorganic nanomaterials can be used as cold cathode devices with ultra-low turn-on voltages, which when coupled with solution processing allow for their use in large area electronics.
Morphological and swelling behavior of cellulose nanofiber (CNF)/poly(vinyl alcohol) (PVA) hydrogels: poly(ethylene glycol) (PEG) as porogen
Authors: Xu Zhaoyang , Li Jianyu , Zhou Huan , Jiang Xiangdong , Yang Chuang , Wang Fei , Pan Yuanyuan , Li Nana , Li Xiaoyan , Shi Lina , Shi Xiaomei
Published: May 2016

Novel interconnected PVA-based hydrogels with controlled porous structure prepared by freezing/thawing and porogen technique are presented in this study.
Graphene oxide reinforced Ni–P coatings for bacterial adhesion inhibition
Authors: Shao Wei , Wu Jimin , Liu Hui , Dong Guanghui , Wang Shuxia , Min Huihua , Huang Min
Published: May 2016

Bacterial adhesion on the surfaces of medical devices, food processing equipment, heat exchangers and ship hulls has been recognized as a widespread problem.
Strengthening of liquid crystal photoalignment on azo dye films: passivation by reactive mesogens
Authors: Tseng Man-Chun , Yaroshchuk Oleg , Bidna Tetyana , Srivastava Abhishek Kumar , Chigrinov Vladimir , Kwok Hoi-Sing
Published: May 2016

Passivation of photoalignment films by continuous layers of reactive mesogen provides stable liquid crystal alignment and electro-optic performance equivalent to that of rubbed polyimide films.
One-step synthesis of hydrophobic fluorinated ordered mesoporous carbon materials
Authors: Dong Xiuqin , Zhao Xueshuang , Wang Lingtao , Zhang Minhua
Published: May 2016

A series of fluorinated ordered mesoporous carbon (FOMC) materials were prepared by a one-pot method.
Selective detection of nitrite ion by an AIE-active tetraphenylethene dye through a reduction step in aqueous media
Authors: Anuradha Anuradha , Latham Kay , Bhosale Sheshanath V.
Published: May 2016

We report selective and sensitive nitrite sensor in water based on AIE-active tetraphenylethene bearing amino functionality.
Effective removal of lead(ii) from wastewater by amine-functionalized magnesium ferrite nanoparticles
Authors: Nonkumwong Jeeranan , Ananta Supon , Srisombat Laongnuan
Published: May 2016

Magnetic nanoadsorbent in the form of amine-functionalized MgFe2O4nanoparticles was successfully synthesized and adopted for Pb2+removal from scenario simulated wastewater.
Small organic molecules based on oxazole/thiazole with excellent performances in green and red phosphorescent organic light-emitting diodes
Authors: Tian Guojian , Wei Xiang , Xiang Ning , Huang Jinhai , Cao Jin , Wang Zixing , Zhang Jianhua , Su Jianhua
Published: May 2016

Four small organic host materials based on oxazole/thiazole have been synthesized and fully characterized. The best performance of compound 2d was a maximum current efficiency of 50.7 cd A−1 for green device and a maximum current efficiency of 18.7 cd A−1 for red device.
Super/hyperhalogen aromatic heterocyclic compounds
Authors: Reddy Gorre Naaresh , Giri Santanab
Published: May 2016

Aromatic heterocyclic molecules with negative electron affinity values can be transformed to highly oxidizing super/hyperhalogens based on a systematic in silico approach.
In situ synthesis of thermo-responsive ACB triblock terpolymer nanoparticles through seeded RAFT polymerization
Authors: Li Quanlong , Li Lei , Wang Wenbin , Zhang Xiaolei , Li Shentong , Tian Qian , Liu Jiaping
Published: May 2016

ACB triblock terpolymer nanoparticles containing two thermo-responsive blocks are prepared by seeded RAFT polymerization and their thermo-response is checked.
Understanding the structural changes and depolymerization of Eucalyptus lignin under mild conditions in aqueous AlCl3
Authors: Shen Xiao-Jun , Wang Bing , Pan-li Huang , Wen Jia-Long , Sun Run-Cang
Published: May 2016

Lignin is a unique renewable source of phenolic products for the potential replacement of fossil fuels. Herein, direct understanding of the chemical transformations and depolymerization mechanism of lignin during AlCl3 pretreatment is presented.
Flame retardant plasticized poly(vinyl chloride) film with selective solar spectral transparent properties
Authors: Yin Xiuping , Zhang Jun
Published: May 2016

The combination of UV absorber, pigment yellow, TCPP and ITOhelps prepare PVC film, which possessing high LOI value (35%), high transmittance in vis region (81.56%) and low transmittance in UV (0.40%), HEV (62.79%) and NIR (39.04%) region.
Stabilizing metastable tetragonal HfO2 using a non-hydrolytic solution-phase route: ligand exchange as a means of controlling particle size
Authors: Waetzig Gregory R. , Depner Sean W. , Asayesh-Ardakani Hasti , Cultrara Nicholas D. , Shahbazian-Yassar Reza , Banerjee Sarbajit
Published: May 2016

A non-hydrolytic condensation route allows for precise control over the size distribution of HfO2 nanocrystals and enables the stabilization of the tetragonal phase of HfO2.
Enhanced Fenton-catalytic efficiency by highly accessible active sites on dandelion-like copper–aluminum–silica nanospheres for water purification
Authors: Lyu Lai , Zhang Lili , Hu Chun , Yang Min
Published: May 2016

Dandelion-like copper–aluminum–silica nanospheres (DCAS Ns) with great exposure, significant accessibility and high stability exhibit high-performance towards water purification via Fenton reaction.
Synthesis of one-dimensional NiFe2O4 nanostructures: tunable morphology and high-performance anode materials for Li ion batteries
Authors: Wang Jianan , Yang Guorui , Wang Ling , Yan Wei
Published: May 2016

Various controllable one-dimensional NiFe2O4 nanostructures were synthesized by electrospinning and hydraulic agitation as high-performance anode materials for lithium ion batteries.
Solid state synthesis, structural characterization and ionic conductivity of bimetallic alkali-metal yttrium borohydrides MY(BH4)4 (M = Li and Na)
Authors: Roedern Elsa , Lee Young-Su , Ley Morten B. , Park Kiho , Cho Young Whan , Skibsted Jørgen , Jensen Torben R.
Published: May 2016

Two bimetallic borohydrides, lithium yttrium tetraborohydride, LiY(BH4)4, and sodium yttrium tetraborohydride, NaY(BH4)4, have been synthesized by thermal treatment and quenching of ball-milled precursors.
Fe-doped CeO2 nanorods for enhanced peroxidase-like activity and their application towards glucose detection
Authors: Jampaiah Deshetti , Srinivasa Reddy T. , Kandjani Ahmad Esmaielzadeh , Selvakannan P. R. , Sabri Ylias M. , Coyle Victoria E. , Shukla Ravi , Bhargava Suresh K.
Published: May 2016

Surface defects of Fe-doped CeO2 nanorods were found to be active sites for increasing peroxidase mimetic activity.
Highly efficient green phosphorescent organic light-emitting diodes with low efficiency roll-off based on iridium(iii) complexes bearing oxadiazol-substituted amide ligands
Authors: Zhang Fuli , Li Weiling , Yu Yue , Jing Yiming , Ma Dongxin , Zhang Fuqiang , Li Suzhi , Cao Guangxiu , Li Zhongyi , Guo Ge , Wei Bin , Zhang Depan , Duan Lian , Li Chunyang , Feng Yafei , Zhai Bin
Published: May 2016

This manuscript describes the highly efficient OLEDs with low efficiency roll-off based on iridium(iii) complexes bearing oxadiazol-substituted amide ligands.
Design, synthesis, characterization and application of a novel electron-deficient moiety 1,5-diazacarbazole in high triplet energy host materials
Authors: Tan Jianghong , Wang Bo , Huang Zhi , Lv Xialei , Yi Wei , Zhuang Shaoqing , Wang Lei
Published: May 2016

A novel electron deficient, high triplet energy moiety 1,5-diazacarbazole (NCz) was designed, synthesized and firstly introduced for the construction of phosphorescent host materials.
Research on configuration strategy for regional energy storage system based on three typical filtering methods
Authors: Cao Minjian , Xu Qingshan , Bian Haihong , Yuan Xiaodong , Du Pengwei
Published: May 2016

With the technological improvement in energy storage field, energy storage systems (ESSs) are exerting increasingly profound influence on future electrical grid which is the combination of numerous renewable energy generation units. However, the problem remains debatable how to appropriately determine the ESS configuration. On the basis of three types of filters, this study proposes a practical and economical method for ESS configuration to stabilise the power fluctuation of distribution feeder lines. According to the historical power data in feeders for a typical day, different ESS configurations are calculated with respect to the rated power and capacity based on various filtering methods. It is found that moving average algorithm is more suitable in the process of solving ESS configuration, considering its compromise between fewer points in average and economical results for ESS configuration. Furthermore, the characteristics of three typical filters as well as explanation for each configuration result are theoretically discussed from the perspective of signal analysis, which helps to illustrate that the circular convolution is the main drawback for larger ESS configuration results solved by ideal low‐pass filtering method.
Experimentally validated model of coupled thermal processes in a laboratory switchgear
Authors: Bedkowski Mateusz , Smolka Jacek , Bulinski Zbigniew , Ryfa Arkadiusz , Ligeza Maciej
Published: May 2016

In this study, the experimentally validated model of coupled thermal processes developed for a three‐phase busbar system of a laboratory switchgear is presented. In the validation process of the mathematical model, over a hundred thermocouples were employed to measure the temperature of the busbar paths and the inner air for three switchgear ampacities of both hermetic and ventilated enclosure. In the numerical model, the fundamental thermal problems were coupled with the electromagnetic field to accurately define the Joule losses and to show the impact of the inductance phenomena on the heat generation in the busbars. Moreover, the power losses due to the busbar junctions were taken into consideration. Thus, a comparison of the available mathematical models describing the joint resistance was studied. In the sensitivity analysis, the effects of the turbulence models, the heat transfer coefficient on external walls and the busbar emissivity definitions on the unit thermal performance were presented.
Fully decentralised multi‐area dynamic economic dispatch for large‐scale power systems via cutting plane consensus
Authors: Zhao Wenmeng , Liu Mingbo , Zhu Jianquan , Li Licheng
Published: May 2016

This study discusses the implementation of a fully decentralised optimisation for the multi‐area dynamic economic dispatch of large‐scale power systems based on the cutting plane consensus (CPC) algorithm. Each area constructs a local master problem to approximate the original problem by generating its own cutting planes and receiving cutting planes from other areas, hence an upper‐level coordinator is not required. Two modifications of the standard CPC algorithm have been developed. First, only the newest cutting planes are transmitted among different areas to reduce the amount of information transferred. Second, to reduce the required number of iterations, a cutting plane is deleted only if it is inactive over consecutive iterations. Theoretically, the convergence and correctness of this algorithm can be guaranteed for power systems with a wide range of scales without tuning the optimisation parameters, and a high‐quality suboptimal solution can still be obtained if the algorithm is prematurely terminated. The proposed method is applied to simulations of a three‐area IEEE Reliability Test System and an actual four‐area 2298‐bus provincial power system to demonstrate its effectiveness.
Improved LSF method for loss estimation and its application in DG allocation
Authors: Fu Xueqian , Chen Haoyong , Cai Runqing , Xuan Peizheng
Published: May 2016

Energy loss represents a traditional key objective in the optimal operation and planning of electrical networks, and various estimation methods have been studied. In this study, two formulas are proposed for calculation of the loss factor (LSF) to improve the classical LSF method based on the minimum load factor (MLF) and the LF. The former is an approximate formula, whose accuracy is good enough for engineering calculations. While the latter is an empirical quadratic equation determined by the statistical analysis, which is more accurate to estimate losses. To conduct a complete feasibility study for project practices, a large amount of measurement data is used to calculate energy losses in a district of Guangdong using the classical LSF method and the improved LSF (ILSF) method. Results of statistical analyses indicate that the real data fall in the proposed three‐dimensional region and the use of MLF can help improve accuracy in the energy losses estimation. The classical and ILSF methods are used to estimate the effect in loss reduction by inserting a distributed generation in a 43‐bus distribution network, and the candidate bus can be identified effectively.
Optimisation‐based switch allocation to improve energy losses and service restoration in radial electrical distribution systems
Authors: López Juan Camilo , Franco John Fredy , Rider Marcos J.
Published: May 2016

This study presents a new methodology for the optimal allocation of switching devices in radial electrical distribution systems (EDSs). A specialised greedy randomised adaptive search procedure (GRASP) algorithm defines the location of a number of switching devices in order to simultaneously improve the following optimisation subproblems related to the use of the allocated switches: (i) the optimal reconfiguration of EDS and (ii) the optimal service restoration of EDS. Eventually, the objective function of the proposed switch allocation algorithm minimises the cost of the total expected energy not supplied, computed after deploying the service restoration, plus the cost of the total annual energy loss computed for every load level in a year, plus the investment costs associated with the number of installed switches. Both optimisation subproblems, i.e. the reconfiguration and the restoration of EDS, are represented by mixed‐integer non‐linear programming (MINLP) models and transformed into mixed‐integer linear programming (MILP) models, using linearisation strategies. MILP models guarantee convergence to optimality by using convex optimisation techniques. Finally, all tests were carried out using a real 136‐node distribution system, considering dispatchable and non‐dispatchable distributed generation resources.
YN/VD connected balance transformer‐based electrical railway negative sequence current compensation system with passive control scheme
Authors: Xie Bin , Zhang Zhiwen , Hu Sijia , Li Yong , Luo Longfu , Sun Shubo
Published: May 2016

A new negative sequence current compensation system (NSCCS) is proposed to improve the power quality in electrical railway power system. The NSCCS consists of a balance transformer in YN/VD connection and a three‐phase converter. The balance transformer used here can supply both two‐phase voltages with 27.5 kV for electrical locomotives and three‐phase voltages for low‐ or medium‐voltage converter. So, a large‐capacity step‐down transformer used to match the voltage of converter is not necessary, which can significantly reduce not only the total cost of the equipment, but also the area of the substation. The system topology is introduced and the compensation principle, mathematical model, detection method, and control strategy are expounded. The non‐linear passive control method for the converter is adopted to design the controller to get a good compensation performance. The simulation and experimental results verify the effectiveness of the compensation system.
Price‐based power management of off‐grid photovoltaic systems with centralised dc bus
Authors: Bellinaso Lucas Vizzotto , Schwertner Christoffer Daniel , Michels Leandro
Published: May 2016

Power management of stand‐alone photovoltaic (PV) systems with centralised dc bus is usually performed using centralised algorithms based on complex state machines. This study proposes an intuitive and modular solution using a price‐based approach. The dc bus is considered a market environment where a fictitious energy price is defined according to energy scarcity. The converters that connect the PV generator, loads, and energy storages to the dc bus choose their operation modes in response to the price. The proposed approach was applied to a stand‐alone PV system with energy storage. Advantages of the proposed technique are scalability and intuitive programming effort due to the market analogy, so it may be helpful to developers of off‐grid PV systems. Experimental results have been carried out to validate the proposed approach, proved effective to manage this system.
Phase angle calculation dynamics of type‐4 wind turbines in rms simulations during severe voltage dips
Authors: Altin Müfit , Göksu Ömer , Sørensen Poul , Morales Ana , Fortmann Jens , Buendia Francisco J.
Published: May 2016

To conduct power system simulations with high shares of wind energy, standard wind turbinemodels, which are aimed to be generic rms models for a wide range of windturbine types, have been developed. As a common practice of rms simulations, thepower electronic interface of wind turbines is assumed to be ideallysynchronised, i.e. grid synchronisation (e.g. phase locked loop(PLL)) is not included in simplified wind turbine models. Aswill be shown in this study, this practice causes simulation convergenceproblems during severe voltage dips and when the loss of synchronism occurs. Inorder to provide the simulation convergence without adding complexity to thegeneric models, a first‐order filtering approach is proposed as a phase anglecalculation algorithm in the grid synchronisation of the rms type‐4 wind turbinemodels. The proposed approach provides robustness for the simulation oflarge‐scale power systems with high shares of wind energy.
Discrimination and identification between mainlobe repeater jamming and target echo by basis pursuit
Authors: Ding Liming , Li Rongfeng , Wang Yongliang , Dai Lingyan , Chen Fengbo
Published: May 2016

Basis pursuit of sparse decomposition is adopted to discriminate and identify the target echo with two kinds of mainlobe jamming named time‐delay repeater jamming and smeared spectrum (SMSP) jamming, which can produce multiple false targets. The main idea is to extract their pulsed differences. The signal model is first transformed to an underdetermined matrix equation, the dictionary is constructed by the function form of the target echo, and then the matrix equation is solved by replacing the l0 norm problem via the l1 norm problem. The identification of time‐delay repeater jamming and the target echo is by the difference of the pulse width. Identifying SMSP jamming and the target echo is by the difference of the chirp rate. The proposed algorithm is particularly relevant to the case that the signals are overlapped. Finally, simulation results demonstrate the efficacy of the proposed method and they show that the method outperforms the conventional time–frequency representation method.
Generalised analytical framework for the stability studies of an AC microgrid
Authors: Kallamadi Manjunath , Sarkar Vaskar
Published: May 2016

The objective is to address the small‐signal stability analysis of a renewable‐driven AC microgrid in the context of the practical usage and application. The state‐space modelling of the system is generalised over all possible microgrid configurations. It is shown that there exist two simple templates to represent the dynamics of any type of load. The dynamics of any type of source (including the utility grid during the grid‐connected operation) can be represented through a single template. Thus, the effective number of the different types of dynamic element is minimised and set fixed irrespective of the actual microgrid composition. In addition, similar loads are represented in the form of a single group to reduce computational complexity. A systematic procedure for constructing the system matrix using the prescribed source and load templates is discussed. The developed framework is applied on a test system having complex loads for both grid‐connected and islanded operations. It is a common observation that system stability is influenced by the interactions between inertial and non‐inertial components. To overcome this issue, suitable parameters are identified and tuned by performing system level study.
Forced vibration analysis of a viscoelastic polymeric piezoelectric microplate with fluid interaction
Authors: Monemian Esfahani Amir , Bahrami Mohsen , Ghaffarian Anbarani Seyed Reza
Published: May 2016

The equations of motion for a viscoelastic polymeric piezoelectric microplate are established based on the thin plate theory and Kelvin–Voigt laws. Polyvinylidene fluoride is chosen as the polymeric piezoelectric material. The plate is assumed to be rectangular and the boundary conditions are clamped at all edges. Liquid is modelled as a damping foundation beneath the plate. The equations are solved using assumed‐mode method along with Newmark's β method. The effects of variation in the input voltage, damping coefficient, viscoelastic parameter, and excitation frequency are discussed. The results are compared with the developed finite element method. An excellent agreement is observed between the two methods.
Prospects of Zn(O,S) as an alternative buffer layer for Cu2ZnSnS4 thin‐film solar cells from numerical simulation
Authors: Zhang Hong , Cheng Shuying , Yu Jinling , Zhou Haifang , Jia Hongjie
Published: May 2016

Zn(O,S) is an attractive alternative to CdS as a buffer layer of Cu2ZnSnS4 (CZTS)‐based solar cell due to its higher bandgap and environmental friendliness. In this work, CZTS solar cell with a structure of CZTS/Zn(O,S)/Al:ZnO was simulated by Solar Cell Capacitance Simulator (SCAPS). The impacts of thickness and acceptor concentration of CZTS, thickness and donor concentration of Zn(O,S) and operating temperature on the performance of CZTS solar cells were investigated. It has been obtained that the optimum thickness of CZTS is between 2000 and 3000 nm and that of Zn(O,S) is about 50 nm. The suitable doping concentrations of CZTS and Zn(O,S) layers are around 1016 and 1017 cm−3, respectively. The temperature coefficient of efficiency is about −0.023 %/K in the CZTS solar cell. All these simulation results will provide some important guidelines for fabricating high efficient CZTS solar cells.
Assessment of a Learning Strategy among Spine Surgeons
Authors: Gotfryd Alberto Ofenhejm , Corredor Jose Alfredo , Teixeira William Jacobsen , Martins Delio Eulálio , Milano Jeronimo , Iutaka Alexandre Sadao
Published: May 2016

Study Design

Pilot test, observational study.

Objective

To evaluate objectively the knowledge transfer provided by theoretical and practical activities during AOSpine courses for spine surgeons.

Methods

During two AOSpine principles courses, 62 participants underwent precourse assessment, which consisted of questions about their professional experience, preferences regarding adolescent idiopathic scoliosis (AIS) classification, and classifying the curves by means of the Lenke classification of two AIS clinical cases. Two learning strategies were used during the course. A postcourse questionnaire was applied to reclassify the same deformity cases. Differences in the correct answers of clinical cases between pre- and postcourse were analyzed, revealing the number of participants whose accuracy in classification improved after the course.

Results

Analysis showed a decrease in the number of participants with wrong answers in both cases after the course. In the first case, statistically significant differences were observed in both curve pattern (83.3%, p  =  0.005) and lumbar spine modifier (46.6%, p  =  0.049). No statistically significant improvement was seen in the sagittal thoracic modifier (33.3%, p  =  0.309). In the second case, statistical improvement was obtained in curve pattern (27.4%, p  =  0.018). No statistically significant improvement was seen regarding lumbar spine modifier (9.8%, p  =  0.121) and sagittal thoracic modifier (12.9%, p  =  0.081).

Conclusion

This pilot test showed objectively that learning strategies used during AOSpine courses improved the participants' knowledge. Teaching strategies must be continually improved to ensure an optimal level of knowledge transfer.
Thirty-Day Morbidity Associated with Pelvic Fixation in Adult Patients Undergoing Fusion for Spinal Deformity
Authors: Kothari Parth , Somani Sulaiman , Lee Nathan J. , Guzman Javier Z. , Leven Dante M. , Skovrlj Branko , Steinberger Jeremy , Kim Jun , Cho Samuel K.
Published: May 2016

Study Design

Retrospective study of prospectively collected data.

Objective

To determine if patients undergoing spinal deformity surgery with pelvic fixation are at an increased risk of morbidity.

Methods

The American College of Surgeons National Surgical Quality Improvement Program is a large multicenter clinical registry that prospectively collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from ~400 hospitals nationwide. Current Procedural Terminology codes were used to query the database between 2010 and 2014 for adults who underwent fusion for spinal deformity. Patients were separated into groups of those with and without pelvic fixation. Univariate analysis and multivariate logistic regression were used to analyze the effect of pelvic fixation on the incidence of postoperative morbidity and other surgical outcomes.

Results

Multivariate analysis showed that pelvic fixation was a significant predictor of overall morbidity (odds ratio [OR] = 2.3, 95% confidence interval [CI]: 1.7 to 3.1, p = 0.0002), intra- or postoperative blood transfusion (OR = 2.3, 95% CI: 1.7 to 3.1 p < 0.0001), extended operative time (OR = 4.7, 95% CI: 3.1 to 7.0 p < 0.0001), and length of stay > 5 days (OR = 2.1, 95% CI 1.5 to 2.8, p < 0.0001) in patients undergoing fusion for spinal deformity. However, fusion to the pelvis did not lead to additional risk for other complications, including wound complications ( p = 0.3191).

Conclusion

Adult patients undergoing spinal deformity surgery with pelvic fixation were not susceptible to increased morbidity beyond increased blood loss, greater operative time, and extended length of stay.
Inkjet-printed vertically emitting solid-state organic lasers
Authors: Mhibik Oussama , Chénais Sébastien , Forget Sébastien , Defranoux Christophe , Sanaur Sébastien
Published: May 2016

In this paper, we show that Inkjet Printing can be successfully applied to external-cavity vertically emitting thin-film organic lasers and can be used to generate a diffraction-limited output beam with an output energy as high as 33.6 μJ with a slope efficiency S of 34%. Laser emission shows to be continuously tunable from 570 to 670 nm using an intracavity polymer-based Fabry-Perot etalon. High-optical quality films with several μm thicknesses are realized, thanks to ink-jet printing. We introduce a new optical material where EMD6415 commercial ink constitutes the optical host matrix and exhibits a refractive index of 1.5 and an absorption coefficient of 0.66 cm−1 at 550–680 nm. Standard laser dyes like Pyrromethene 597 and Rhodamine 640 are incorporated in solution to the EMD6415 ink. Such large size “printed pixels” of 50 mm2 present uniform and flat surfaces, with roughness measured as low as 1.5 nm in different locations of a 50 μm × 50 μm AFM scan. Finally, as the gain capsules fabricated by Inkjet printing are simple and do not incorporate any tuning or cavity element, they are simple to make, have a negligible fabrication cost, and can be used as fully disposable items. This work opens the way towards the fabrication of really low-cost tunable visible lasers with an affordable technology that has the potential to be widely disseminated.
Semiflexible polymers under good solvent conditions interacting with repulsive walls
Authors: Egorov Sergei A. , Milchev Andrey , Virnau Peter , Binder Kurt
Published: May 2016

Solutions of semiflexible polymers confined by repulsive planar walls are studied by density functional theory and molecular dynamics simulations, to clarify the competition between the chain alignment favored by the wall and the depletion caused by the monomer-wall repulsion. A coarse-grained bead-spring model with a bond bending potential is studied, varying both the contour length and the persistence length of the polymers, as well as the monomer concentration in the solution (good solvent conditions are assumed throughout, and solvent molecules are not included explicitly). The profiles of monomer density and pressure tensor components near the wall are studied, and the surface tension of the solution is obtained. While the surface tension slightly decreases with chain length for flexible polymers, it clearly increases with chain length for stiff polymers. Thus, at fixed density and fixed chain length, the surface tension also increases with increasing persistence length. Chain ends always are enriched near the wall, but this effect is much larger for stiff polymers than for flexible ones. Also the profiles of the mean square gyration radius components near the wall and the nematic order parameter are studied to clarify the conditions where wall-induced nematic order occurs.
Insights into the variability of nucleated amyloid polymerization by a minimalistic model of stochastic protein assembly
Authors: Eugène Sarah , Xue Wei-Feng , Robert Philippe , Doumic Marie
Published: May 2016

Self-assembly of proteins into amyloid aggregates is an important biological phenomenon associated with human diseases such as Alzheimer’s disease. Amyloid fibrils also have potential applications in nano-engineering of biomaterials. The kinetics of amyloid assembly show an exponential growth phase preceded by a lag phase, variable in duration as seen in bulk experiments and experiments that mimic the small volumes of cells. Here, to investigate the origins and the properties of the observed variability in the lag phase of amyloid assembly currently not accounted for by deterministic nucleation dependent mechanisms, we formulate a new stochastic minimal model that is capable of describing the characteristics of amyloid growth curves despite its simplicity. We then solve the stochastic differential equations of our model and give mathematical proof of a central limit theorem for the sample growth trajectories of the nucleated aggregation process. These results give an asymptotic description for our simple model, from which closed form analytical results capable of describing and predicting the variability of nucleated amyloid assembly were derived. We also demonstrate the application of our results to inform experiments in a conceptually friendly and clear fashion. Our model offers a new perspective and paves the way for a new and efficient approach on extracting vital information regarding the key initial events of amyloid formation.
Study of Ar and Ar-CO2 microwave surfaguide discharges by optical spectroscopy
Authors: Silva Tiago , Britun Nikolay , Godfroid Thomas , van der Mullen Joost , Snyders Rony
Published: May 2016

A surfaguide microwave discharge operating at 2.45 GHz in Ar and Ar-CO2 mixtures is studied using diagnostics methods based on optical emission spectroscopy. The population densities of Ar metastable and resonant states of the lowest group of excited levels (1sx) are investigated for several experimental conditions using the self-absorption technique. It is found that the densities of these levels, ranging from 1017 to 1016 m−3 for the pure Ar case, are dependent on the discharge pressure and applied power. The electron temperature and electron density are calculated via the balances of creation/loss mechanisms of radiative and metastable levels. In the range of the studied experimental conditions (50–300 W of applied power and 0.5–6 Torr of gas pressure), the results have shown that lower values of electron temperature correspond to higher values of power and pressure in the discharge. Adding CO2 to the argon plasma results in a considerable decrease (about 3 orders of magnitude) of the Ar metastable atom density. The feasibility of using the ratio of two Ar emission line intensities to measure the electron temperature in CO2 discharges with small Ar admixtures is studied.
On determining characteristic length scales in pressure-gradient turbulent boundary layers
Authors: Vinuesa R. , Bobke A. , Örlü R. , Schlatter P.
Published: May 2016

In the present work, we analyze three commonly used methods to determine the edge of pressure gradient turbulent boundary layers: two based on composite profiles, the one by Chauhan et al. [“Criteria for assessing experiments in zero pressure gradient boundary layers,” Fluid Dyn. Res. 41, 021404 (2009)] and the one by Nickels [“Inner scaling for wall-bounded flows subject to large pressure gradients,” J. Fluid Mech. 521, 217–239 (2004)], and the other one based on the condition of vanishing mean velocity gradient. Additionally, a new method is introduced based on the diagnostic plot concept by Alfredsson et al. [“A new scaling for the streamwise turbulence intensity in wall-bounded turbulent flows and what it tells us about the ‘outer’ peak,” Phys. Fluids 23, 041702 (2011)]. The boundary layers developing over the suction and pressure sides of a NACA4412 wing section, extracted from a direct numerical simulation at chord Reynolds number Rec = 400 000, are used as the test case, besides other numerical and experimental data from favorable, zero, and adverse pressure-gradient flat-plate turbulent boundary layers. We find that all the methods produce robust results with mild or moderate pressure gradients, although the composite-profile techniques require data preparation, including initial estimations of fitting parameters and data truncation. Stronger pressure gradients (with a Rotta–Clauser pressure-gradient parameter β larger than around 7) lead to inconsistent results in all the techniques except the diagnostic plot. This method also has the advantage of providing an objective way of defining the point where the mean streamwise velocity is 99% of the edge velocity and shows consistent results in a wide range of pressure gradient conditions, as well as flow histories. Collapse of intermittency factors obtained from a wide range of pressure-gradient and Re conditions on the wing further highlights the robustness of the diagnostic plot method to determine the boundary layer thickness (equivalent to δ99) and the edge velocity in pressure gradient turbulent boundary layers.
Influence of surfactant on the drop bag breakup in a continuous air jet stream
Authors: Zhao Hui , Zhang Wen-Bin , Xu Jian-Liang , Li Wei-Feng , Liu Hai-Feng
Published: May 2016

The deformation and breakup of surfactant-laden drops is a common phenomenon in nature and numerous practical applications. We investigate influence of surfactant on the drop bag breakup in a continuous air jet stream. The airflow would induce the advection diffusion of surfactant between interface and bulk of drop. Experiments indicate that the convective motions of deforming drop would induce the non-equilibrium distribution of surfactant, which leads to the change of surface tension. When the surfactant concentration is smaller than critical micelle concentration (CMC), with the increase of surface area of drop, the surface tension of liquid-air interface and the critical Weber number will increase. When the surfactant concentration is bigger than CMC, the micelle can be considered as the source term, which can supply the monomers. So in the presence of surfactant, there would be the significant nonlinear variation on the critical Weber number of bag breakup. We build the dynamic non-monotonic relationship between concentrations of surfactant and critical Weber number theoretically. In the range of parameters studied, the experimental results are consistent with the model estimates.
An alternative derivation of ring-polymer molecular dynamics transition-state theory
Authors: Hele Timothy J. H. , Althorpe Stuart C.
Published: May 2016

In a previous article [T. J. H. Hele and S. C. Althorpe, J. Chem. Phys. 138, 084108 (2013)], we showed that the t → 0+ limit of ring-polymer molecular dynamics (RPMD) rate-theory is also the t → 0+ limit of a new type of quantum flux-side time-correlation function, in which the dividing surfaces are invariant to imaginary-time translation; in other words, that RPMD transition-state theory (RMPD-TST) is a t → 0+ quantum transition-state theory (QTST). Recently, Jang and Voth [J. Chem. Phys. 144, 084110 (2016)] rederived this quantum t → 0+ limit and claimed that it gives instead the centroid-density approximation. Here we show that the t → 0+ limit derived by Jang and Voth is in fact RPMD-TST.
Effects of irradiation distance on supply of reactive oxygen species to the bottom of a Petri dish filled with liquid by an atmospheric O2/He plasma jet
Authors: Kawasaki Toshiyuki , Kusumegi Shota , Kudo Akihiro , Sakanoshita Tomohiro , Tsurumaru Takuya , Sato Akihiro , Uchida Giichiro , Koga Kazunori , Shiratani Masaharu
Published: May 2016

The impact of irradiation distances on plasma jet-induced specific effects on the supply of reactive oxygen species (ROS) to the bottom of a Petri dish filled with liquid was investigated using a KI-starch gel reagent that can be employed as a ROS indicator even in water. O3 exposure experiments without plasma irradiation were also performed to elucidate the specific effects of the plasma jet. Relative concentrations of ROS transported to the bottom were evaluated using absorbance measurements. The results indicated that ROS supply to the bottom is markedly enhanced by the plasma jet irradiation at shorter irradiation distances, whereas similar results could not be obtained for the O3 exposure. In these cases, the liquid mixing in the depth direction was also enhanced by the plasma jet irradiation only, and the supply of reactive atomic oxygen to the liquid surface was markedly increased as well.
Characterization of enzymatic micromachining for construction of variable cross-section microchannel topologies
Authors: Huang Jen-Huang , Han Duanduan , Ruggles Molly E. , Jayaraman Arul , Ugaz Victor M.
Published: May 2016

The ability to harness enzymatic activity as an etchant to precisely machine biodegradable substrates introduces new possibilities for microfabrication. This flow-based etching is straightforward to implement, enabling patterning of microchannels with topologies that incorporate variable depth along the cross-sectional dimension. Additionally, unlike conventional small-molecule formulations, the macromolecular nature of enzymatic etchants enables features to be precisely positioned. Here, we introduce a kinetic model to characterize the enzymatic machining process and its localization by co-injection of a macromolecular inhibitor species. Our model captures the interaction between enzyme, inhibitor, and substrate under laminar flow, enabling rational prediction of etched microchannel profiles so that cross-sectional topologies incorporating complex lateral variations in depth can be constructed. We also apply this approach to achieve simultaneous widening of an entire network of microchannels produced in the biodegradable polymeric substrate poly(lactic acid), laying a foundation to construct systems incorporating a broad range of internal cross-sectional dimensions by manipulating the process conditions.
Efficient solution on solving 3D Maxwell equations using stable semi-implicit splitting method
Authors: Cen Wei , Gu Ning
Published: May 2016

In this paper, we propose an efficient solution on solving 3-dimensional (3D) time-domain Maxwell equations using the semi-implicit Crank-Nicholson (CN) method for time domain discretization with advantage of unconditional time stability. By applying the idea of fractional steps method (FSM) to the CN scheme, the proposed method provides a much simpler and efficient implementation than a direct implementation of the CN scheme. Compared with the alternating-direction implicit (ADI) method and explicit finite-difference time-domain approach (FDTD), it significantly saves the computational resource like memory and CPU time while remains similar numerical accuracy.
Optical properties of functionalized Ti3C2T2 (T = F, O, OH) MXene: First-principles calculations
Authors: Berdiyorov G. R.
Published: May 2016

Role of surface termination on the dielectric and optical properties of Ti3C2T2 (T = F, O, OH) MXene is studied using first-principles density functional theory. The results show that the surface functionalization has a significant impact on the optical properties of the MXene. For example, in the visible range of the spectrum, the oxidized sample shows larger absorption, whereas surface fluorination results in weaker absorption as compared to pristine MXene. In the ultraviolet energy range, all functional groups lead to the enhancement of both absorption and reflectivity of the material. Dielectric properties of MXene are also sensitive to the surface functionalization. Our findings demonstrate the importance of surface termination on the optical properties of the MXene.