bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced multi-phonon Raman scattering and nonlinear optical power limiting in ZnO:Au nanostructures
Authors: Udayabhaskar R. , Karthikeyan B. , Sreekanth P. , Philip Reji
Published: January 2015

Enhanced Raman scattering and nonlinear optical power limiting in ZnO:Au nanostructures is demonstrated.
Hydrolase-catalyzed asymmetric carbon–carbon bond formation in organic synthesis
Authors: Guan Zhi , Li Ling-Yu , He Yan-Hong
Published: January 2015

This article reviews the hydrolase-catalyzed asymmetric carbon–carbon bond-forming reactions for the preparation of enantiomerically enriched compounds in organic synthesis.
PEG based random copolymer micelles as drug carriers: the effect of hydrophobe content on drug solubilization and cytotoxicity
Authors: Laskar Partha , Saha Biswajit , Ghosh Sudip Kumar , Dey Joykrishna
Published: January 2015

The effect of hydrophobe content on PEG based random polymeric micelles as drug carriers: a comparative study.
Novel screen printed potentiometric sensors for the determination of oxicams
Authors: Khaled Elmorsy , Kamel Manal S. , Hassan Hassan N. , Abd El-Alim Sameh H. , Aboul-Enein Hassan Y.
Published: January 2015

Screen printed sensors based on carbon nanotubes/β-cyclodextrin nanocomposite was applied for potentiometric determination of oxicam derivatives. Sensors showed improved potential stability and lifetime detection limit of 6 × 10−7 mol L−1.
Controllable synthesis of fluorapatite microcrystals decorated with silver nanoparticles and their optical properties
Authors: Li Di , Jiang Deli , Xie Jimin
Published: January 2015

An EDTA-assisted single-step hydrothermal method is developed for the controlled preparation of fluorapatite microcrystals (FHAp MPs) decorated with silver nanoparticles (Ag NPs).
Fabrication of MnOx heterogeneous catalysts from wet sludge for degradation of azo dyes by activated peroxymonosulfate
Authors: Xu Lili , Liu Wanpeng , Li Xingfa , Rashid Sadia , Shen Chensi , Wen Yuezhong
Published: January 2015

For dewatering and resource utilization of sewage sludge, we proposed a strategy that integrates wet sludge treatment with catalyst preparation and heavy metals in catalysts have been solidified in catalysts to prevent their leaching into solution.
Synthesis, characterization and drug release studies of poly(2-hydroxyethyl methacrylate)/KIT-5 nanocomposite as an innovative organic–inorganic hybrid carrier system
Authors: Javad Kalbasi Roozbeh , Zirakbash Ali
Published: January 2015

PHEMA/KIT-5 with various pore sizes was prepared. Efficient encapsulation of drug molecules inside the pores of the hybrid material and controlled release of them in an aqueous medium, suggest the great promise of the composite as a carrier system.
Nanosize α-Bi2O3 decorated Bi2MoO6via an alkali etching process for enhanced photocatalytic performance
Authors: Hao Zhiqiang , Xu Lingling , Wei Bo , Fan Linlin , Liu Yang , Zhang Mingyi , Gao Hong
Published: January 2015

The surface modification of Bi2MoO6 by decorated nanosize α-Bi2O3 was realized via an alkali etching process and an enhanced photocatalytic performance on photodagradation of RhB was observed.
An alkylthieno-2-yl flanked dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene-based low band gap conjugated polymer for high performance photovoltaic solar cells
Authors: Guo Pengzhi , Xia Yangjun , Huang Fei , Luo Guoping , Li Jianfeng , Zhang Peng , Zhu Yuancheng , Yang Chunyan , Wu Hongbin , Cao Yong
Published: January 2015

A conjugated polymer from 5,10-dialkylthieno-2-yl-dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene and naphtho[1,2-c:5,6-c]bis[1,2,5]thiadiazole derivative, was synthesized, and inverted polymer solar cells with a power conversion efficiency of 7.52% was achieved.
Bioluminescent tools for the analysis of G-protein-coupled receptor and arrestin interactions
Authors: Hattori Mitsuru , Ozawa Takeaki
Published: January 2015

New protein-based bioluminescent probes for monitoring GPCR interaction with β-arrestin are presented.
Multifunctional, marvelous polyimide aerogels as highly efficient and recyclable sorbents
Authors: Zhang Li , Wu Juntao , Zhang Xiaomin , Gong Guangming , Liu Jingang , Guo Lin
Published: January 2015

Novel polyimide aerogels with high absorption capacity and excellent recyclability for oils and organic liquids are fabricated by freeze-drying.
Click-chemistry approach for graphene modification: effective reinforcement of UV-curable functionalized graphene/polyurethane acrylate nanocomposites
Authors: Yu Bin , Shi Yongqian , Yuan Bihe , Liu Lu , Yang Hongyu , Tai Qilong , Lo Siuming , Song Lei , Hu Yuan
Published: January 2015

This work presents an effective method of preparing graphene reinforced UV-curable materials.
Low temperature synthesis of carbon fibres and metal-filling carbon nanoparticles with laser irradiation into near-critical benzene
Authors: Fukuda Takahiro , Hayasaki Yasuhiro , Hasumura Takashi , Katsube Yoshihiro , Whitby Raymond L. D. , Maekawa Toru
Published: January 2015

A low temperature methodology for synthesising carbon nanostructures was developed utilising near-critical benzene.
Total synthesis of Sparstolonin B, a potent anti-inflammatory agent
Authors: Wang Yongqiang , Wang Chao , Wang Yuanxun , Dong Lijin , Sun Jian
Published: January 2015

Two concise routes for the first total synthesis of Sparstolonin B have been described.
One-pot synthesis of α-iodoketones from alcohols using ammonium iodide and Oxone® in water
Authors: Reddy Marri Mahender , Swamy Peraka , Naresh Mameda , Srujana Kodumuri , Durgaiah Chevella , Rao Tumula Venkateshwar , Narender Nama
Published: January 2015

A novel and green protocol for the synthesis of α-iodoketones from various secondary alcohols in aqueous media is reported.
A microwave assisted one pot synthesis of novel ammonium based dicationic ionic liquids
Authors: Bhatt Darshak R. , Maheria Kalpana C. , Parikh Jigisha K.
Published: January 2015

A greener one pot synthesis of novel ammonium based dicationic ionic liquids is carried out under microwave conditions. The present method provides a better yield and less reaction time compared to the conventional methods.
A simple and versatile approach to self-healing polymers and electrically conductive composites
Authors: Xie Tingwan , Zhang Huan , Lin Yangju , Xu Yuanze , Ruan Yonghong , Weng Wengui , Xia Haiping
Published: January 2015

In this study, a simple and versatile approach to self-healing polymers and electrically conductive composites is reported.
Highly efficient copper-imprinted functionalized mesoporous organosilica nanocomposites as a recyclable catalyst for click synthesis of 1,2,3-triazole derivatives under ultrasound irradiation: multivariate study by factorial design of experiments
Authors: Naeimi Hossein , Nejadshafiee Vajihe , Masoum Saeed
Published: January 2015

Synthesis of 1,2,3-triazoles under optimized conditions by experimental design via three parameter of Cu@PMO NCs content, ultrasonud irradiation and reaction time.
Brushing up from “anywhere” under sunlight: a universal surface-initiated polymerization from polydopamine-coated surfaces
Authors: Sheng Wenbo , Li Bin , Wang Xiaolong , Dai Bin , Yu Bo , Jia Xin , Zhou Feng
Published: January 2015

A generalized surface-initiated photografting procedure, which utilizes polydopamine as a photosensitive initiating layer, allows functionalization of almost any substrate with thin polymer films under sunlight.
A facile route to electronically conductive polyelectrolyte brushes as platforms of molecular wires
Authors: Wolski Karol , Szuwarzyński Michał , Zapotoczny Szczepan
Published: January 2015

Conjugated polyelectrolyte brushes grafted from a conductive surface and forming a 1D macromolecular pathway for charge transport are synthesized.
Design of a robust superhydrophobic surface: thermodynamic and kinetic analysis
Authors: Sarkar Anjishnu , Kietzig Anne-Marie
Published: January 2015

We analyze superhydrophobic robustness from the dual perspectives of kinetics and thermodynamics, and thus provide topological and chemical characteristics of a surface with square pillars of micrometer length scale to sustain liquid impalement.
4H-1,2,6-Thiadiazin-4-one-containing small molecule donors and additive effects on their performance in solution-processed organic solar cells
Authors: Hermerschmidt Felix , Kalogirou Andreas S. , Min Jie , Zissimou Georgia A. , Tuladhar Sachetan M. , Ameri Tayebeh , Faber Hendrik , Itskos Grigorios , Choulis Stelios A. , Anthopoulos Thomas D. , Bradley Donal D. C. , Nelson Jenny , Brabec Christoph J. , Koutentis Panayiotis A.
Published: January 2015

Donor–acceptor–donors containing 4H-1,2,6-thiadiazinone are presented and used in organic solar cells.
Recent progress of long‐term evolution device‐to‐device in third‐generation partnership project standardisation
Authors: Sun Shaohui , Gao Qiubin , Chen Wenhong , Zhao Rui , Peng Ying
Published: January 2015

Device‐to‐device (D2D) is considered as a promising technique to increase resource utilisation and to provide new application in future wireless networks. This study reviews the standardisation progress of D2D in third‐generation partnership project. Three scenarios, in‐coverage, partial‐coverage and out‐of‐coverage, are defined. For these scenarios, channel model is obtained by the amendment of existing channel model. The function of D2D operation is divided into three building blocks: synchronisation, discovery and communication. The synchronisation procedure and synchronisation signal/channel are discussed first. Then the design aspects of D2D discovery and communication are discussed in detail, including channel structure design, resource allocation mechanisms, interference management and so on. Future works towards post Rel‐12 releases are also briefly outlined.
Game‐theoretic approach to energy‐efficient resource allocation in device‐to‐device underlay communications
Authors: Zhou Zhenyu , Dong Mianxiong , Ota Kaoru , Shi Ruifeng , Liu Zhiheng , Sato Takuro
Published: January 2015

Despite the numerous benefits brought by device‐to‐device (D2D) communications, the introduction of D2D into cellular networks poses many new challenges in the resource allocation design because of the co‐channel interference caused by spectrum reuse and limited battery life of user equipment's (UEs). Most of the previous studies mainly focus on how to maximise the spectral efficiency and ignore the energy consumption of UEs. In this study, the authors study how to maximise each UE's Energy Efficiency (EE) in an interference‐limited environment subject to its specific quality of service and maximum transmission power constraints. The authors model the resource allocation problem as a non‐cooperative game, in which each player is self‐interested and wants to maximise its own EE. A distributed interference‐aware energy‐efficient resource allocation algorithm is proposed by exploiting the properties of the nonlinear fractional programming. The authors prove that the optimal solution obtained by the proposed algorithm is the Nash equilibrium of the non‐cooperative game. The authors also analyse the tradeoff between EE and SE and derive closed‐form expressions for EE and SE gaps.
Sociality‐aware resource allocation for device‐to‐device communications in cellular networks
Authors: Wang Li , Liu Lu , Cao Xianghui , Tian Xiaohua , Cheng Yu
Published: January 2015

Exploiting direct transmissions between geographically close mobile users without passing through the base stations, device‐to‐device (D2D) communications contribute significant improvement to the spectral efficiency of cellular networks. In D2D‐assisted cellular networks, the social interaction of mobile users is an important property that will affect the practical performance and should be seriously accounted in the network resource allocation, which is yet to be fully explored. In this study, the authors investigate the social interactions for D2D transmissions and develop a contact time model to characterise the D2D links. A D2D link can be considered for resource allocation only when the two users encounter and their contact time is enough long to complete a meaningful transmission. They formulate and compare both sociality‐blind and sociality‐aware optimisation problems for resource allocation in D2D‐assisted cellular networks. Extensive numerical results are presented, validating that the sociality‐aware resource allocation can achieve higher performance than that of the sociality‐blind approach.
Semi‐blind parallel factor based receiver for joint symbol and channel estimation in amplify‐and‐forward multiple‐input multiple‐output relay systems
Authors: Du Jianhe , Yuan Chaowei , Zhang Jinbo
Published: January 2015

In this study, the authors consider a new space‐time coding scheme for two‐hop amplify‐and‐forward (AF) relay multiple‐input multiple‐output (MIMO) relay communication systems. This scheme, called multiple Khatri–Rao space‐time coding, which combines symbol stream blocking, spatial precoding and time‐domain spreading. The authors show that the received signals at the destination node can be formulated as two parallel factor (PARAFAC) models, and then a novel semi‐blind receiver is derived using a two‐stage iterative fitting algorithm for joint symbol and channel estimation. Under the assumption that channel state information (CSI) is not available neither at the relay nodes nor at the destination node, the proposed semi‐blind receiver operates close to the zero forcing receiver with perfect CSI. Moreover, without any channel training sequence, the proposed semi‐blind receiver provides the destination node with full knowledge of all channel matrices involved in the transmission. Simulation results illustrate the performance of the proposed semi‐blind receiver in comparison with alternative approaches.
Distributed robust consensus of linear multi‐agent systems with switching topologies
Authors: Li Zixi
Published: January 2015

This paper studies the consensus problem of multi‐agent systems consisting of general linear node dynamics with external disturbances in transmission channels under fixed and switching communication topologies. A distributed observer‐type robust consensus protocol based on relative output measurements is proposed. A model transformation approach is introduced to address the robust consensus of multi‐agent systems. Some conditions for robust consensus are given in terms of linear matrix inequalities for fixed and jointly connected communication topologies. A multi‐step robust consensus protocol design procedure is further presented. Finally, the effectiveness of the theoretical results is demonstrated through numerical simulations.
Coagulation in Patients with Severe Sepsis
Authors: Levi Marcel , Poll Tom
Published: January 2015

In the majority of patients with severe sepsis, systemic activation of coagulation is present. Increasing evidence points to an extensive cross-talk between coagulation and inflammation that may play an important role in the pathogenesis of sepsis. Inflammation not only leads to activation of coagulation, but coagulation also considerably affects inflammatory activity. Molecular pathways that contribute to inflammation-induced activation of coagulation have been precisely identified. Proinflammatory cytokines and other mediators are capable of activating the coagulation system and downregulating important physiological anticoagulant pathways. Activation of the coagulation system and ensuing thrombin generation is dependent on expression of tissue factor on activated mononuclear cells and endothelial cells, and is insufficiently counteracted by TFPI. Simultaneously, endothelial-bound anticoagulant mechanism, in particular the protein C system, is shutoff by proinflammatory cytokines. In addition, fibrin removal is severely inhibited, because of inactivation of the fibrinolytic system, caused by an upregulation of its main inhibitor, plasminogen activator inhibitor type 1 (PAI-1). Increased fibrin formation and impaired removal lead to (micro)vascular thrombosis, which may result in tissue ischemia and subsequent organ damage. The cornerstone of the management of coagulation in sepsis is the specific and vigorous treatment of the underlying disorder. Strategies aimed at the inhibition of coagulation activation may theoretically be justified and have been found beneficial in experimental and initial clinical studies. Heparin may be an effective anticoagulant approach and alternative strategies comprise restoration of physiological anticoagulant pathways.
Profound Endothelial Damage Predicts Impending Organ Failure and Death in Sepsis
Authors: Johansen Maria , Johansson Pär , Ostrowski Sisse , Bestle Morten , Hein Lars , Jensen Anne , Søe-Jensen Peter , Andersen Mads , Steensen Morten , Mohr Thomas , Thormar Katrin , Lundgren Bettina , Cozzi-Lepri Alessandro , Lundgren Jens , Jensen Jens-Ulrik
Published: January 2015

Endothelial damage contributes to organ failure and mortality in sepsis, but the extent of the contribution remains poorly quantified. Here, we examine the association between biomarkers of superficial and profound endothelial damage (syndecan-1 and soluble thrombomodulin [sTM], respectively), organ failure, and death in sepsis. The data from a clinical trial, including critically ill patients predominantly suffering sepsis (Clinicaltrials.gov: NCT00271752) were studied. Syndecan-1 and sTM levels at the time of study enrollment were determined. The predictive ability of biomarker levels on death and organ failures during follow-up were assessed in Cox models adjusted for potential confounders including key organ dysfunction measures assessed at enrollment. Of the 1,103 included patients, 418 died. sTM levels at the time of enrollment independently predicted risk of death in adjusted models (hazard ratio [HR] [highest quartile > 14 ng/mL vs. lowest quartile < 7 ng/mL] 2.2 [95% confidence interval [CI]: 1.2–4.0], p = 0.02, respectively). Conversely, syndecan-1 levels failed to predict death (adjusted HR [> 240 vs. < 70 ng/mL] 1.0 [95% CI: 0.6–1.5], p = 0.67). sTM but not syndecan-1 levels at enrollment predicted risk of multiple organ failure during follow-up (HR [> 14 ng/mL vs. < 7 ng/mL] 3.5 [95% CI: 1.5–8.3], p = 0.005 and 2.0 [95% CI: 0.8–5.0], p = 0.1321, respectively). Profound damage to the endothelium independently predicts risk of multiple organ failure and death in septic patients. Our findings also suggest that the detrimental effect of profound endothelial damage on risk of death operates via mechanisms other than causing organ failures per se. Therefore, damage to the endothelium appears centrally involved in the pathogenesis of death in sepsis and could be a target for intervention.
Hypercoagulability and Venous Thromboembolism in Burn Patients
Authors: Meizoso Jonathan , Ray Juliet , Allen Casey , Van Haren Robert , Ruiz Gabriel , Namias Nicholas , Schulman Carl , Pizano Louis , Proctor Kenneth
Published: January 2015

To our knowledge, this is the first comprehensive review on the subject of venous thromboembolism (VTE) and hypercoagulability in burn patients. Specific changes in coagulability are reviewed using data from thromboelastography and other techniques. Disseminated intravascular coagulation in burn patients is discussed. The incidence and risk factors associated with VTE in burn patients are then examined, followed by the use of low-molecular-weight heparin thromboprophylaxis and monitoring techniques using antifactor Xa levels. The need for large, prospective trials in burn patients is highlighted, especially in the areas of VTE incidence and safe, effective thromboprophylaxis.
Heparin-Induced Thrombocytopenia in Critically Ill Patients
Authors: Warkentin Theodore
Published: January 2015

Many critically ill patients receive heparin, either before intensive care unit (ICU) admission (e.g., postcardiac surgery), for prophylaxis/treatment of thrombosis, for hemodialysis/filtration, or even incidentally (e.g., flushing of intravascular catheters), and are therefore at risk for developing immune heparin-induced thrombocytopenia (HIT), a prothrombotic drug reaction caused by platelet-activating antiplatelet factor 4 (PF4)/heparin antibodies. However, HIT explains at most 1 in 100 thrombocytopenic ICU patients (HIT frequency 0.3–0.5% vs. 30–50% background frequency of ICU-associated thrombocytopenia), and most patients who form anti-PF4/heparin antibodies do not develop HIT; hence, HIT overdiagnosis often occurs. This review discusses HIT-related issues relevant to ICU patients, including how to (1) distinguish HIT both clinically and serologically from non-HIT–related thrombocytopenia; (2) recognize HIT-mimicking disorders, such as the acute disseminated intravascular coagulation (DIC)/liver necrosis-limb necrosis syndrome; (3) prevent HIT in the ICU through use of low-molecular-weight heparin; and (4) treat HIT, including awareness of “PTT confounding” when anticoagulating patients with DIC.
Hemostasis and Thrombosis in Continuous Renal Replacement Treatment
Authors: Oudemans-van Straaten Heleen
Published: January 2015

During continuous renal replacement therapy, the delicate equilibrium of hemostasis is disturbed. Owing to a complex interaction of critical illness, uremia, use of an extracorporeal circuit and anticoagulation, patients exhibit both hypercoagulability and an increased risk of bleeding. Contact of blood with foreign material initiates coagulation by triggering the contact activation coagulation pathway, the tissue factor–factor VIIa pathway and activation of platelets and monocytes, which adhere to the membrane. The interaction with critical illness induced alterations further enhances coagulation and inflammation. Classical markers of coagulation, prothrombin and activated thromboplastin time, and platelet count do not detect the procoagulant state. Critically ill patients also have in increased risk of bleeding and anticoagulation used for circuit clotting enhances this risk. Heparin is most commonly used. Heparin increases the risk of bleeding. Its efficacy and safety are further compromised by antithrombin deficiency, heparin binding to acute phase proteins and apoptotic and necrotic cells, and by its unpredictable effects on inflammation. Its interference with anticoagulation is therefore unreliable during critical illness. Citrate provides regional anticoagulation and increases biocompatibility. It is better tolerated than heparin and confers less bleeding, less transfusion, and longer circuit life.
Self-organized capacity for energy extraction by clustering particles in two-species suspension flow at small Reynolds numbers
Authors: Shih Che-Ming , Kung Chun-Fei , Chang Chien-Cheng , Pan Tsorng-Whay
Published: January 2015

Particles in a two-phase flow may develop into clusters of different sizes. This study aimed to calculate the capacities of particles of different cluster sizes for extracting energy in a two-species suspension flow. The scaled total and rotational energy distributions are found to exhibit the behaviors of self-organized criticality. The organized motion is analyzed by examining individual energy contributions with respect to various parameters: cluster size, particle size ratio, and solid volume fraction.
Finite ion temperature effects on scrape-off layer turbulence
Authors: Mosetto Annamaria , Halpern Federico D. , Jolliet Sébastien , Loizu Joaquim , Ricci Paolo
Published: January 2015

Ion temperature has been measured to be of the same order, or higher, than the electron temperature in the scrape-off layer (SOL) of tokamak machines, questioning its importance in determining the SOL turbulent dynamics. Here, we present a detailed analysis of finite ion temperature effects on the linear SOL instabilities, such as the resistive and inertial branches of drift waves and ballooning modes, and a discussion of the properties of the ion temperature gradient (ITG) instability in the SOL, identifying the ηi=Ln/LTi threshold necessary to drive the mode unstable. The non-linear analysis of the SOL turbulent regimes by means of the gradient removal theory is performed, revealing that the ITG plays a negligible role in limited SOL discharges, since the ion temperature gradient is generally below the threshold for driving the mode unstable. It follows that the resistive ballooning mode is the prevailing turbulence regime for typical limited SOL parameters. The theoretical estimates are confirmed by non-linear flux-driven simulations of SOL plasma dynamics.
Towards an exact theory of linear absorbance and circular dichroism of pigment-protein complexes: Importance of non-secular contributions
Authors: Dinh Thanh-Chung , Renger Thomas
Published: January 2015

A challenge for the theory of optical spectra of pigment-protein complexes is the equal strength of the pigment-pigment and the pigment-protein couplings. Treating both on an equal footing so far can only be managed by numerically costly approaches. Here, we exploit recent results on a normal mode analysis derived spectral density that revealed the dominance of the diagonal matrix elements of the exciton-vibrational coupling in the exciton state representation. We use a cumulant expansion technique that treats the diagonal parts exactly, includes an infinite summation of the off-diagonal parts in secular and Markov approximations, and provides a systematic perturbative way to include non-secular and non-Markov corrections. The theory is applied to a model dimer and to chlorophyll (Chl) a and Chl b homodimers of the reconstituted water-soluble chlorophyll-binding protein (WSCP) from cauliflower. The model calculations reveal that the non-secular/non-Markov effects redistribute oscillator strength from the strong to the weak exciton transition in absorbance and they diminish the rotational strength of the exciton transitions in circular dichroism. The magnitude of these corrections is in a few percent range of the overall signal, providing a quantitative explanation of the success of time-local convolution-less density matrix theory applied earlier. A close examination of the optical spectra of Chl a and Chl b homodimers in WSCP suggests that the opening angle between Qy transition dipole moments in Chl b homodimers is larger by about 9∘ than for Chl a homodimers for which a crystal structure of a related WSCP complex exists. It remains to be investigated whether this change is due to a different mutual geometry of the pigments or due to the different electronic structures of Chl a and Chl b.
A new facility for the synchrotron radiation-based calibration of transfer radiation sources in the ultraviolet and vacuum ultraviolet spectral range
Authors: Thornagel Reiner , Fliegauf Rolf , Klein Roman , Kroth Simone , Paustian Wolfgang , Richter Mathias
Published: January 2015

The Physikalisch-Technische Bundesanstalt (PTB) has a long tradition in the calibration of radiation sources in the ultraviolet and vacuum ultraviolet spectral range, with traceability to calculable synchrotron radiation. Within this context, new instrumentation in the PTB laboratory at the Metrology Light Source (MLS) has been put into operation that opens up extended and improved calibration possibilities. A new facility for radiation source calibrations has been set up in the spectral range from 7 nm to 400 nm based on a combined normal incidence-grazing incidence monochromator. The facility can be used for the calibration of transfer sources in terms of spectral radiant intensity or mean spectral radiance, with traceability to the MLS primary source standard. We describe the design and performance of the experimental station and give examples of some commissioning results.
Investigation of negative bias temperature instability dependence on fin width of silicon-on-insulator-fin-based field effect transistors
Authors: Young Chadwin D. , Neugroschel Arnost , Majumdar Kausik , Matthews Ken , Wang Zhe , Hobbs Chris
Published: January 2015

The fin width dependence of negative bias temperature instability (NBTI) of double-gate, fin-based p-type Field Effect Transistors (FinFETs) fabricated on silicon-on-insulator (SOI) wafers was investigated. The NBTI degradation increased as the fin width narrowed. To investigate this phenomenon, simulations of pre-stress conditions were employed to determine any differences in gate oxide field, fin band bending, and electric field profile as a function of the fin width. The simulation results were similar at a given gate stress bias, regardless of the fin width, although the threshold voltage was found to increase with decreasing fin width. Thus, the NBTI fin width dependence could not be explained from the pre-stress conditions. Different physics-based degradation models were evaluated using specific fin-based device structures with different biasing schemes to ascertain an appropriate model that best explains the measured NBTI dependence. A plausible cause is an accumulation of electrons that tunnel from the gate during stress into the floating SOI fin body. As the fin narrows, the sidewall device channel moves in closer proximity to the stored electrons, thereby inducing more band bending at the fin/dielectric interface, resulting in a higher electric field and hole concentration in this region during stress, which leads to more degradation. The data obtained in this work provide direct experimental proof of the effect of electron accumulation on the threshold voltage stability in FinFETs.
Spectral restoration in high resolution electron energy loss spectroscopy based on iterative semi-blind Lucy-Richardson algorithm applied to rutile surfaces
Authors: Lazzari Rémi , Li Jingfeng , Jupille Jacques
Published: January 2015

A new spectral restoration algorithm of reflection electron energy loss spectra is proposed. It is based on the maximum likelihood principle as implemented in the iterative Lucy-Richardson approach. Resolution is enhanced and point spread function recovered in a semi-blind way by forcing cyclically the zero loss to converge towards a Dirac peak. Synthetic phonon spectra of TiO2 are used as a test bed to discuss resolution enhancement, convergence benefit, stability towards noise, and apparatus function recovery. Attention is focused on the interplay between spectral restoration and quasi-elastic broadening due to free carriers. A resolution enhancement by a factor up to 6 on the elastic peak width can be obtained on experimental spectra of TiO2(110) and helps revealing mixed phonon/plasmon excitations.
Short-range stabilizing potential for computing energies and lifetimes of temporary anions with extrapolation methods
Authors: Sommerfeld Thomas , Ehara Masahiro
Published: January 2015

The energy of a temporary anion can be computed by adding a stabilizing potential to the molecular Hamiltonian, increasing the stabilization until the temporary state is turned into a bound state, and then further increasing the stabilization until enough bound state energies have been collected so that these can be extrapolated back to vanishing stabilization. The lifetime can be obtained from the same data, but only if the extrapolation is done through analytic continuation of the momentum as a function of the square root of a shifted stabilizing parameter. This method is known as analytic continuation of the coupling constant, and it requires—at least in principle—that the bound-state input data are computed with a short-range stabilizing potential. In the context of molecules and ab initio packages, long-range Coulomb stabilizing potentials are, however, far more convenient and have been used in the past with some success, although the error introduced by the long-rang nature of the stabilizing potential remains unknown. Here, we introduce a soft-Voronoi box potential that can serve as a short-range stabilizing potential. The difference between a Coulomb and the new stabilization is analyzed in detail for a one-dimensional model system as well as for the 2Πu resonance of CO2−, and in both cases, the extrapolation results are compared to independently computed resonance parameters, from complex scaling for the model, and from complex absorbing potential calculations for CO2−. It is important to emphasize that for both the model and for CO2−, all three sets of results have, respectively, been obtained with the same electronic structure method and basis set so that the theoretical description of the continuum can be directly compared. The new soft-Voronoi-box-based extrapolation is then used to study the influence of the size of diffuse and the valence basis sets on the computed resonance parameters.
Sublinear scaling for time-dependent stochastic density functional theory
Authors: Gao Yi , Neuhauser Daniel , Baer Roi , Rabani Eran
Published: January 2015

A stochastic approach to time-dependent density functional theory is developed for computing the absorption cross section and the random phase approximation (RPA) correlation energy. The core idea of the approach involves time-propagation of a small set of stochastic orbitals which are first projected on the occupied space and then propagated in time according to the time-dependent Kohn-Sham equations. The evolving electron density is exactly represented when the number of random orbitals is infinite, but even a small number (≈16) of such orbitals is enough to obtain meaningful results for absorption spectrum and the RPA correlation energy per electron. We implement the approach for silicon nanocrystals using real-space grids and find that the overall scaling of the algorithm is sublinear with computational time and memory.
Cross two photon absorption in a silicon photonic crystal waveguide fiber taper coupler with a physical junction
Authors: Sarkissian Raymond , O'Brien John
Published: January 2015

Cross two photon absorption in silicon is characterized using a tapered fiber photonic crystal silicon waveguide coupler. There is a physical junction between the tapered fiber and the waveguide constituting a stand-alone device. This device is used to obtain the spectrum for cross two photon absorption coefficient per unit volume of interaction between photons of nondegenerate energy. The corresponding Kerr coefficient per unit volume of interaction is also experimentally extracted. The thermal resistance of the device is also experimentally determined and the response time of the device is estimated for on-chip all-optical signal processing and data transfer between optical signals of different photon energies.
A non-modal analytical method to predict turbulent properties applied to the Hasegawa-Wakatani model
Authors: Friedman B. , Carter T. A.
Published: January 2015

Linear eigenmode analysis often fails to describe turbulence in model systems that have non-normal linear operators and thus nonorthogonal eigenmodes, which can cause fluctuations to transiently grow faster than expected from eigenmode analysis. When combined with energetically conservative nonlinear mode mixing, transient growth can lead to sustained turbulence even in the absence of eigenmode instability. Since linear operators ultimately provide the turbulent fluctuations with energy, it is useful to define a growth rate that takes into account non-modal effects, allowing for prediction of energy injection, transport levels, and possibly even turbulent onset in the subcritical regime. We define such a non-modal growth rate using a relatively simple model of the statistical effect that the nonlinearities have on cross-phases and amplitude ratios of the system state variables. In particular, we model the nonlinearities as delta-function-like, periodic forces that randomize the state variables once every eddy turnover time. Furthermore, we estimate the eddy turnover time to be the inverse of the least stable eigenmode frequency or growth rate, which allows for prediction without nonlinear numerical simulation. We test this procedure on the 2D and 3D Hasegawa-Wakatani model [A. Hasegawa and M. Wakatani, Phys. Rev. Lett. 50, 682 (1983)] and find that the non-modal growth rate is a good predictor of energy injection rates, especially in the strongly non-normal, fully developed turbulence regime.
Modeling grown-in dislocation multiplication on prismatic slip planes for GaN single crystals
Authors: Gao B. , Kakimoto K.
Published: January 2015

To dynamically model the grown-in dislocation multiplication on prismatic slip planes for GaN single crystal growth, the Alexander–Haasen (AH) model, which was originally used to model the plastic deformation of silicon crystals, is extended to GaN single crystals. By fitting the model to the experimental data, we found that it can accurately describe the plastic deformation of GaN caused by prismatic slip. A set of unified parameters for the AH model at different temperatures can be found. This model provides a possible method to minimize grown-in dislocations caused due to prismatic slip by optimizing growing and cooling conditions during GaN single crystal growth.
Effects of angular confinement and concentration to realistic solar cells
Authors: Höhn O. , Kraus T. , Schwarz U. T. , Bläsi B.
Published: January 2015

In standard solar cells, light impinges under a very small angular range, whereas the solar cell emits light into the whole half space. Due to this expansion of etendué, entropy is generated, which limits the maximal efficiency of solar cells. This limit can be overcome by either increasing the angle of incidence by concentration or by decreasing the angle of emission by an angularly confining element or by a combination of both. In an ideal solar cell with radiative recombination as the only loss mechanism, angular confinement and concentration are thermodynamically equivalent. It is shown that concentration in a device, where non-radiative losses such as Shockley-Read-Hall and Auger recombination are considered, is not equivalent to angular confinement. As soon as non-radiative losses are considered, the gain in efficiency due to angular confinement drops significantly in contrast to the gain caused by concentration. With the help of detailed balance calculations, it is furthermore shown that angular confinement can help to increase the efficiency of solar cells under concentrated sunlight even if no measurable gain is expected for the solar cell under 1-sun-illumination. Our analysis predicts a relative gain of 3.14% relative in efficiency for a realistic solar cell with a concentration factor of 500.
Surface acoustic wave amplification by direct current-voltage supplied to graphene film
Authors: Insepov Z. , Emelin E. , Kononenko O. , Roshchupkin D. V. , Tnyshtykbayev K. B. , Baigarin K. A.
Published: January 2015

Using a high-resolution X-Ray diffraction measurement method, the surface acoustic wave (SAW) propagation in a graphene film on the surface of a Ca3TaGa3Si2O14 (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here, we show that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10 V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.
The unexpected beneficial effect of the L-valley population on the electron mobility of GaAs nanowires
Authors: Marin E. G. , Ruiz F. G. , Godoy A. , Tienda-Luna I. M. , Gámiz F.
Published: January 2015

The impact of the L-valley population on the transport properties of GaAs cylindrical nanowires (NWs) is analyzed by numerically calculating the electron mobility under the momentum relaxation time approximation. In spite of its low contribution to the electron mobility (even for high electron populations in small NWs), it is demonstrated to have a beneficial effect, since it significantly favours the Γ-valley mobility by screening the higher Γ-valley energy subbands.
Nitrogen diffusion in hafnia and the impact of nitridation on oxygen and hydrogen diffusion: A first-principles study
Authors: Sathiyanarayanan Rajesh , Pandey R. K. , Murali K. V. R. M.
Published: January 2015

Using first-principles simulations, we have computed incorporation energies and diffusion barriers of ammonia, the nitrogen molecule and atomic nitrogen in monoclinic hafnia (m-HfO2). Our calculations show that ammonia is likely to dissociate into an NH2 molecular unit, whereas the nitrogen molecule remains as a molecule either in the interstitial space or at an oxygen lattice site. The lowest energy pathway for the diffusion of atomic nitrogen interstitials consists of the hopping of the nitrogen interstitial between neighboring three-coordinated lattice oxygen atoms that share a single Hf atom, and the barrier for such hops is determined by a switching mechanism. The substitutional nitrogen atom shows a preference for diffusion through the doubly positive oxygen vacancy-mediated mechanism. Furthermore, we have investigated the impact of nitrogen atoms on the diffusion barriers of oxygen and hydrogen interstitials in m-HfO2. Our results show that nitrogen incorporation has a significant impact on the barriers for oxygen and hydrogen diffusion: nitrogen atoms attract oxygen and hydrogen interstitials diffusing in the vicinity, thereby slowing down (reducing) their diffusion (diffusion length).
Surface plasmon oscillations on a quantum plasma half-space
Authors: Moradi Afshin
Published: January 2015

We investigate the propagation of surface electrostatic oscillations on a quantum plasma half-space, taking into account the quantum effects. We derive the quantum surface wave frequencies of the system, by means the quantum hydrodynamic theory in conjunction with the Poisson equation and applying the appropriate additional quantum boundary conditions. Numerical results show in the presence of the slow nonlocal variations, plasmon wave energies of the system are significantly modified and plasmonic oscillations with blue-shifted frequencies emerge.
Quantification of the spin-Hall anti-damping torque with a resonance spectrometer
Authors: Emori Satoru , Nan Tianxiang , Oxholm Trevor M. , Boone Carl T. , Jones John G. , Howe Brandon M. , Brown Gail J. , Budil David E. , Sun Nian X.
Published: January 2015

We present a simple technique using a cavity-based resonance spectrometer to quantify the anti-damping torque due to the spin Hall effect. Modification of ferromagnetic resonance is observed as a function of small DC current in sub-mm-wide strips of bilayers, consisting of magnetically soft FeGaB and strong spin-Hall metal Ta. From the detected current-induced linewidth change, we obtain an effective spin Hall angle of 0.08–0.09 independent of the magnetic layer thickness. Our results demonstrate that a sensitive resonance spectrometer can be a general tool to investigate spin Hall effects in various material systems, even those with vanishingly low conductivity and magnetoresistance.
Analysis of the actuation properties of charged multilayer films
Authors: Allahyarov Elshad , Löwen Hartmut , Zhu Lei
Published: January 2015

Combining elasticity theory with electrostatics, we calculate the actuation response of a charged multilayer film, which is composed of consecutively stacked piezoelectric and polymeric elastomer layers, with respect to an applied voltage. Depending on the individual material properties and polarity of the applied voltage, we show that the composite multilayer can exhibit actuation properties which are considerably better than the response of the individual constituents. It is also shown that there is a window for applied voltages within which the thickness of the composite film expands, a condition that cannot be achieved in single layer films. In particular, we apply and evaluate our theory for various piezoelectric and dielectric elastomers. The results obtained will be helpful to develop tailored composite materials with specific actuation characteristics.
Volumetric density trends (TB/in.3) for storage components: TAPE, hard disk drives, NAND, and Blu-ray
Authors: Fontana R. E. , Decad G. M. , Hetzler S. R.
Published: January 2015

Memory storage components, i.e., hard disk drives, tape cartridges, solid state drives using Flash NAND chips, and now optical cartridges using Blu-ray disks, have provided annual increases in memory capacity by decreasing the area of the memory cell associated with the technology of these components. The ability to reduce bit cell sizes is now being limited by nano-technology physics so that in order for component manufacturers to continue to increase component capacity, volumetric enhancements to the storage component are now being introduced. Volumetric enhancements include adding more tape per cartridge, more disk platters per drive, and more layers of memory cells on the silicon NAND substrate or on the optical disk substrate. This paper describes these volumetric strategies, projects density trends at the bit cell level, and projects volumetric trends at the component level in order to forecast future component capacity trends.
Local doping of graphene devices by selective hydrogen adsorption
Authors: Park Min , Yun Yong Ju , Lee Minwoo , Jeong Dae Hong , Jun Yongseok , Park Yung Woo , Kim Byung Hoon
Published: January 2015

N-type graphene fabricated by exposure to hydrogen gas has been previously studied. Based on this property of graphene, herein, we demonstrate local doping in single-layer graphene using selective adsorption of dissociative hydrogen at 350 K. A graphene field effect transistor was produced covered with PMMA on half of the graphene region. The charge neutrality point of the PMMA-window region shifted to a negative gate voltage (VG) region prominently compared with that of the PMMA-covered region. Consequently, a single graphene p-n junction was obtained by measuring the VG-dependent resistance of the whole graphene region. This method presents opportunities for developing and controlling the electronic structure of graphene and device applications.
Numerical simulation of two dimensional sine-Gordon solitons using modified cubic B-spline differential quadrature method
Authors: Shukla H. S. , Tamsir Mohammad , Srivastava Vineet K.
Published: January 2015

In this paper, a modified cubic B-spline differential quadrature method (MCB-DQM) is employed for the numerical simulation of two-space dimensional nonlinear sine-Gordon equation with appropriate initial and boundary conditions. The modified cubic B-spline works as a basis function in the differential quadrature method to compute the weighting coefficients. Accordingly, two dimensional sine-Gordon equation is transformed into a system of second order ordinary differential equations (ODEs). The resultant system of ODEs is solved by employing an optimal five stage and fourth-order strong stability preserving Runge–Kutta scheme (SSP-RK54). Numerical simulation is discussed for both damped and undamped cases. Computational results are found to be in good agreement with the exact solution and other numerical results available in the literature.