bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of pyrazolo[5,1-a]isoquinolines via a silver(i)-catalyzed reaction of (1-arylethylidene)hydrazides with N′-(2-alkynylbenzylidene)hydrazides
Authors: Gong Xinxing , Wu Jie
Published: October 2015

A silver(i)-catalyzed reaction of (1-arylethylidene)hydrazides with N′-(2-alkynylbenzylidene)hydrazides via [3 + 2] cycloaddition and intramolecular rearrangement is reported, which proceeds through azo-alkene and isoquinolinium-2-yl amide intermediates.
Fabrication of polyacrylonitrile hollow fiber membranes from ionic liquid solutions
Authors: Kim DooLi , Moreno Nicolas , Nunes Suzana Pereira
Published: October 2015

PAN hollow fiber membranes with good pore morphology have been fabricated using solvent mixtures of ionic liquids and DMSO, which has a lower toxicity than other commonly used polar organic solvents.
Cu(0)-mediated living radical polymerisation in dimethyl lactamide (DML); an unusual green solvent with limited environmental impact
Authors: Bertrand Olivier , Wilson Paul , Burns James A. , Bell Gordon A. , Haddleton David M.
Published: October 2015

The synthesis of poly-acrylates, methacrylates and styrene derivatives by SET-LRP is reported in a user and environmentally friendly “green” solvent, dimethyl lactamide (DML).
Microwave synthesis of high-flux NaY zeolite membranes in fluoride media
Authors: Hu Na , Zheng Yihong , Yang Zhen , Zhou Rongfei , Chen Xiangshu
Published: October 2015

High-flux NaY zeolite membranes were synthesized using low-cost mullite supports by microwave heating in fluoride media.
The supramolecular hydrogel based on hyperbranched polyglycerol and dextran as a scaffold for living cells and drug delivery
Authors: Li Jing , Li Huimin , Yang Xiaoyuan , Luo Pingyan , Wu Zhongming , Zhang Xinge
Published: October 2015

A novel supramolecular hydrogel AD-g-HPG/CD-g-Dex based on host–guest interaction as a scaffold for cell proliferation and drug delivery.
Removal of a reactive dye and hexavalent chromium by a reusable bacteria attached electrospun nanofibrous web
Authors: San Keskin Nalan Oya , Celebioglu Aslı , Sarioglu Omer Faruk , Ozkan Alper Devrim , Uyar Tamer , Tekinay Turgay
Published: October 2015

Bacteria have been immobilized onto a polysulfone nanofibrous web and used for the removal of reactive dye and heavy metal.
A variety of metal–organic and supramolecular networks constructed from a new flexible multifunctional building block bearing picolinate and terephthalate functionalities: hydrothermal self-assembly, structural features, magnetic and luminescent properties
Authors: Shao Yong-Liang , Cui Yan-Hui , Gu Jin-Zhong , Kirillov Alexander M. , Wu Jiang , Wang Ya-Wen
Published: October 2015

A novel multifunctional building block was designed and applied for the synthesis of diverse coordination compounds.
Synthesis of 1,3,5-trisubstituted pyrazoline derivatives and their applications
Authors: Mehta Jugal V. , Gajera Sanjay B. , Thakor Parth , Thakkar Vasudev R. , Patel Mohan N.
Published: October 2015

The biological activities of pyrazoline based Ru(iii) complexes were carried out using gel electrophoresis, absorption titration, cellular level cytotoxicity and molecular docking study. Compounds exhibit potent nuclease and cytotoxicity activity.
Interface mediated semiconducting to metallic like transition in ultrathin Bi2Se3 films on (100) SrTiO3 grown by molecular beam epitaxy
Authors: Debnath Anil K. , Prasad R. , Singh Ajay , Samanta Soumen , Kumar Ashwini , Bohra Anil , Bhattacharya Debarati , Basu Saibal , Joshi Niraj , Aswal Dinesh K. , Gupta S. K.
Published: October 2015

Compressive strains due to the structural phase transition of SrTiO3 substrate facilitate semiconductor to metal like transition in Bi2Se3 thin films.
Sensitive fluorescence “turn-on” detection of bleomycin based on a superquenched perylene–DNA complex
Authors: Kong Rong-Mei , Sun Ni-Na , Qu Fengli , Wu Haiyan , Wang Hua , You Jinmao
Published: October 2015

We introduced a superquenched perylene–DNA complex based method for sensitive fluorescence “turn-on” detection of bleomycin.
Preparation of LiBOB via rheological phase method and its application to mitigate voltage fade of Li1.16[Mn0.75Ni0.25]0.84O2cathode
Authors: Lian Fang , Li Yang , He Yi , Guan Hongyan , Yan Kun , Qiu Weihua , Chou Kuo-Chih , Axmann Peter , Wohlfahrt-Mehrens Margret
Published: October 2015

High-purity LiBOB, synthesizedvianovel rheological phase reaction method without further recrystallization, mitigated voltage-fade of Li-rich cathode as electrolyte additive.
Fabrication of a flexible copper pattern based on a sub-micro copper paste by a low temperature plasma technique
Authors: Gao Yue , Zhang Hao , Jiu Jinting , Nagao Shijo , Sugahara Tohru , Suganuma Katsuaki
Published: October 2015

Sub-micro copper particles with different sizes and size distributions were successfully synthesized by a simple large scale polyol process with a trace amount of the Na2S additive.
Anisotropic swelling in hydrogels formed by cooperatively aligned megamolecules
Authors: Okajima M. K. , Mishima R. , Amornwachirabodee K. , Mitsumata T. , Okeyoshi K. , Kaneko T.
Published: October 2015

A cyanobacterial polysaccharide, sacran, which has a high molecular length over 30 μm, forms in-plane oriented film by casting. The film creates uniaxially-swelling hydrogels with a micrometer thickness.
Copper phthalocyanine modified SiO2/C electrode as a biomimetic electrocatalyst for 4-aminophenol in the development of an amperometric sensor
Authors: Rahim Abdur , Muhammad Nawshad , Nishan Umar , Khan Umar Saeed , Rehman Fozia , Kubota Lauro Tatsuo , Gushikem Yoshitaka
Published: October 2015

SiO2/C/CuPc sensor response for 4-aminophenol oxidation.
On-column enzymatic synthesis of melanin nanoparticles using cryogenic poly(AAM-co-AGE) monolith and its free radical scavenging and electro-catalytic properties
Authors: Saini Amardeep Singh , Tripathi Anuj , Melo Jose Savio
Published: October 2015

“Novel approach for biosynthesis of melanin nanoparticles by sequestrial biotransformation of l-DOPA using immobilized tyrosinase enzyme in macroporous poly(AAm-co-AGE) monolith”.
Activated carbon nanospheres derived from bio-waste materials for supercapacitor applications – a review
Authors: A Divyashree , Hegde Gurumurthy
Published: October 2015

Supercapacitors are perfect energy storage devices; they can be charged almost instantly and release energy over a long time.
Efficient synthesis of xanthene derivatives using carboxyl functionalized graphene quantum dots as an acidic nano-catalyst under microwave irradiation
Authors: Shomali Ashkan , Valizadeh Hassan , Banan Alireza , Mohammad-Rezaei Rahim
Published: October 2015

Carboxyl functionalized graphene quantum dots (CGQDs) were applied as an efficient acidic catalyst for the coupling reaction of 2-naphthole and benzaldehyde derivatives for the preparation of 14H-dibenzo xanthene derivatives.
Investigation on the microstructure of as-deformed NiCr microwires using TEM
Authors: Zhou X. W. , Qi Y. D. , Liu X. D. , Wei J. J. , Wu W. D.
Published: October 2015

The deformed microstructures of Ni20Cr wires include amorphous GB, crystal GB, edge dislocations, and twins. Edge dislocations exist in GB and grain interiors. Twinning angles is approximately 141° and 146°, respectively.
Photocatalytic proton reduction with ruthenium and cobalt complexes immobilized on fumed reversed-phase silica
Authors: Bachmann C. , Probst B. , Oberholzer M. , Fox T. , Alberto R.
Published: October 2015

Non-covalent binding of water reduction catalysts and photosensitizers to hydrophobic silica particles represents a general approach for heterogenizing molecular water splitting components.
Dual gold/photoredox-catalyzed C(sp)–H arylation of terminal alkynes with diazonium salts
Authors: Tlahuext-Aca Adrian , Hopkinson Matthew N. , Sahoo Basudev , Glorius Frank
Published: October 2015

The arylation of alkyl and aromatic terminal alkynes by a dual gold/photoredox catalytic system is described.
High-silica nanocrystalline Beta zeolites: efficient synthesis and catalytic application
Authors: Martínez-Franco Raquel , Paris Cecilia , Martínez-Armero Marta E. , Martínez Cristina , Moliner Manuel , Corma Avelino
Published: October 2015

An efficient synthesis methodology to obtain homogeneous nanosized high-silica Beta zeolites (∼10–20 nm) with high solid yields (above 95%) using simple alkyl-substituted flexible dicationic OSDAs is described.
Advanced 1,1-carboboration reactions with pentafluorophenylboranes
Authors: Kehr Gerald , Erker Gerhard
Published: October 2015

The advanced 1,1-carboboration reaction converts alkynes to alkenylboranes and allows a variety of sequential ring forming reactions of bis(alkynyl) compounds.
Lithium storage properties of in situ synthesized Li2FeSiO4 and LiFeBO3 nanocomposites as advanced cathode materials for lithium ion batteries
Authors: Hu Lin , Yang Jinlong , Amiinu Ibrahim Saana , Kang Xiaochun , Zhang Wei , Mu Shichun
Published: October 2015

The kinetics towards charge transfer and lithium ion diffusion are effectively enhanced with in situ adding small amounts of LiFeBO3, leading to a remarkably improved charge–discharge performance of Li2FeSiO4 as advanced cathode materials for lithium ion batteries.
Novel PtCo alloy nanoparticle decorated 2D g-C3N4 nanosheets with enhanced photocatalytic activity for H2 evolution under visible light irradiation
Authors: Han Changcun , Lu Yan , Zhang Junlong , Ge Lei , Li Yujing , Chen Changfeng , Xin Yongji , Wu Linen , Fang Siman
Published: October 2015

Novel PtCo/g-C3N4 nanosheets with efficient visible light induced photocatalytic activity for H2 evolution.
Mechanisms of methane decomposition and carbon species oxidation on the Pr0.42Sr0.6Co0.2Fe0.7Nb0.1O3−σ electrode with high catalytic activity
Authors: Zhang Peng , Guan Guoqing , Khaerudini Deni S. , Hao Xiaogang , Xue Chunfeng , Han Minfang , Kasai Yutaka , Abudula Abuliti
Published: October 2015

Carbon deposition characteristics on PSCFN and Ni–YSZ due to thermal CH4 decomposition are investigated by using TPR technique.
One-step chemically controlled wet synthesis of graphene nanoribbons from graphene oxide for high performance supercapacitor applications
Authors: Khandelwal Mahima , Kumar Anil
Published: October 2015

Chemically controlled GO reduction produces (150–300 nm wide and ∼0.15–1 mm long) GNRs displaying high-performance supercapacitor applications.
miR-122 plays an important role in ochratoxin A-induced hepatocyte apoptosis in vitro and in vivo
Authors: Zhu Liye , Yu Tao , Qi Xiaozhe , Yang Bo , Shi Lei , Luo Haoshu , He Xiaoyun , Huang Kunlun , Xu Wentao
Published: October 2015

OTA can induce hepatotoxicity. Our previous research has shown that miRNAs play important roles in the OTA-induced hepatotoxicity. And miR-122 is the most abundant miRNA in the liver and is involved in diverse biological processes. This study was performed to clarify the role of miR-122 in OTA-induced hepatotoxicity. The expression levels of miR-122 and the target genes were quantified by real-time PCR. The OTA-induced apoptosis of hepatocyte and HepG2 cells was evaluated using a TUNEL kit, a CCK-8 kit, a flow cytometer and Hoechst 33342. miR-122 was inhibited in HepG2 cells. The results revealed that OTA affected rat hepatocyte apoptosis. miR-122 decreased at 4 weeks but increased at 13 weeks in the OTA-treated livers, and increased in the OTA-treated HepG2 cells; and the mRNA levels of CCNG1 and Bcl-w increased at 4 weeks and decreased at 13 weeks in the high-dose OTA-treatment groups and decreased in HepG2 cells. The apoptosis of HepG2 cells displayed a dose-related increase with OTA. However, the inhibition of miR-122 greatly reduced OTA-induced apoptosis. p53 decreased in vivo and in vitro. miR-122 is a primary effector of OTA-induced hepatocyte apoptosis through the CCNG1/p53 pathway and Bcl-w/caspase-3 pathway in vivo and in vitro. And miR-122 plays an important role in OTA-induced hepatotoxicity.
Workload prediction using run‐length encoding for runtime processor power management
Authors: Kim S.W. , Kim T.M. , Yoo C.
Published: October 2015

In processor power management research, workload prediction is a requisite for adjusting frequency without performance loss, and previous studies have proposed various prediction algorithms. Among them, methods based on the workload history table are lightweight and have high prediction accuracy for a variable workload. However, such prediction algorithms lose their prediction accuracy in the case of repeated workload. An improved workload prediction method using run‐length encoding is proposed, which handles workload repetition. Evaluation results show that the proposed algorithm improves the prediction of repeated workload by up to 14% and also improves 4% of energy saving.
Adaptive and joint blind calibration of gain, time‐skew and bandwidth mismatch errors in time‐interleaved ADCs
Authors: De Teyou G.K. , Petit H. , Loumeau P.
Published: October 2015

A new blind calibration scheme for M time‐interleaved analogue‐to‐digital converters (ADCs), which models gain, time‐skew and bandwidth mismatches as components of a transfer function mismatch, is proposed. Numerical results on the emerging generation of WiFI IEEE 802.11.ac with 12‐bit ADCs show the effectiveness of the method.
Depth sensor and DVL‐aided vertical channel damping loop design for underwater vehicles
Authors: Choe Tok Son , Ra Won Sang , Park Jin Bae
Published: October 2015

A novel vertical channel damping loop design method that uses not only a depth sensor but also a Doppler velocity log (DVL) for underwater vehicles is proposed. In the proposed method, the loop gains are calculated by adopting the steady‐state Kalman filter gain with consideration of characteristics of the depth sensor and the DVL. The simulation results demonstrate that the proposed method achieves better performance than the conventional method.
Design of small dual band‐notched UWB slot antenna
Authors: Zhang Yong‐Ping , Li Chun‐Mao
Published: October 2015

The design of a small printed slot antenna for ultra‐wideband application is presented. The antenna is simply formed by an L‐shaped slot embedded at the centre of the ground plane, a 50 Ω microstrip‐fed line, a rectangular slit connected with the L‐shaped slot and another rectangular slit at the bottom of the ground plane. The antenna has small dimensions of 16 × 28 × 0.8 mm3. The impedance bandwidth with 10 dB return loss of the antenna is from 3.1 to 10.6 GHz, in which there is two rejected bands which cover 3.3–3.73 and 5.15–5.9 GHz.
3D printed iris bandpass filters for millimetre‐wave applications
Authors: Zhang B. , Zirath H.
Published: October 2015

Two iris bandpass filters implemented by three‐dimensional (3D) printing technology for millimetre‐wave applications are demonstrated for the first time. The filters are designed at the E‐band (60–90 GHz), and fabricated by selective laser melting using CuSn15 alloy powder. A shifted passband and increased insertion loss are observed, which is caused by the fabrication tolerance of dimensional control and surface roughness. Methods to compensate the fabrication tolerance are proposed and the design procedures are provided. The presented results prove the great potential of 3D printing technology for millimetre wave applications.
Estimation accuracy of multi‐cell massive multiple‐input multiple‐output systems in correlated Rician fading channel
Authors: AL‐Salihi H. , Said F. , Nallanathan A. , Wong K.
Published: October 2015

The performance analysis of a multi‐user multi‐cell massive multiple‐input multiple‐output system that applies a conventional channel estimation technique, namely the linear minimum mean square error over correlated Rician fading is investigated. Based on the analysis, it is found that increasing the line‐of‐sight component can enhance the estimation accuracy.
Design guidelines of tunnelling field‐effect transistors for the suppression of work‐function variation
Authors: Choi W.Y.
Published: October 2015

Design guidelines to suppress the work‐function variation (WFV) effects of tunnelling field‐effect transistors (TFETs) have been discussed in comparison with metal–oxide–semiconductor FETs for the first time. The effects of metal‐gate materials and their grain size on the WFV have been investigated. The simulation results show that the selection of appropriate gate material and the reduction of metal grain size are the effective solutions to the WFV of TFETs.
Defining the mutual coupling of capacitive power transfer for wireless power transfer
Authors: Huang L. , Hu A.P.
Published: October 2015

Capacitive power transfer (CPT) based on electric field coupling has been proposed recently as an alternative technology for wireless power transfer, and a good understanding of the capacitive coupling is of great importance in the design and evaluation of CPT systems. A new term named capacitive coupling coefficient kE is introduced to provide a quantitative measure of the coupling condition between the coupling plates. The term is derived by modelling the capacitive coupling plates based on electric charge balance, and its physical meaning is explained clearly in relation to the equivalent primary/secondary and mutual capacitances, which is also experimentally demonstrated by comparing two CPT systems with different cross‐coupling configurations.
High‐power up to 4 W characteristics of the capacitive microwave power sensor with grounded beam
Authors: Yan Hao , Liao Xiaoping
Published: October 2015

The high‐power up to 4 W characteristic of a capacitive microwave power sensor with grounded MEMS beam is investigated. This device is fabricated by GaAs MMIC (microwave monolithic integrated circuit) technology. Experimental results indicate that the sensitivity of power sensor gradually degenerates with input power increasing continually. The measurement results are divided into three regions: pre‐saturated, saturated and over‐saturated regions. The corresponding sensitivities are 0.95, 0.76 and 0.56 fF/W at 10 GHz, respectively. This effect is caused by the device's capacitive mismatch at high‐power, and the modified formula is calculated in sections.
Robust beamforming using beam‐to‐reference weighting diagonal loading and Bayesian framework
Authors: Wu Chao , Guo Yanmeng , Na Yueyue , Wang Xiaofei , Fu Qiang , Yan Yonghong
Published: October 2015

A novel robust diagonal loading (DL) algorithm against steering vector mismatch is proposed. The beam‐to‐reference ratio is estimated first and then used as a weighting factor for variable DL. The Bayesian framework is applied eventually to obtain the weight vector. In contrast to traditional methods, the proposed method achieves good performance without using any optimisation toolboxes or matrix eigendecomposition operations.
Decoding of non‐binary low‐density parity‐check codes based on the genetic algorithm and applications over mobile fading channels
Authors: Liu Xingcheng , Liang Chulong , Zhang Yuanbin , Zhang Lin
Published: October 2015

In this study, an efficient decoding algorithm is proposed to decode non‐binary low‐density parity‐check (LDPC) codes. The algorithm is derived from the belief‐propagation (BP) decoding with genetic algorithm of binary LDPC codes. For the proposed algorithm, two decoding constraints are introduced to determine variable nodes which are considered highly reliable. The messages from these highly reliable variable nodes are then magnified with an appropriate parameter γ. This process can make the messages propagate in the Tanner graph more efficiently. Simulation results show that, compared with the fast Fourier transform‐based BP algorithm, the proposed algorithm can have an equal or better performance in low bit‐error‐rate region over both the additive white Gaussian noise channels and the mobile fading channels.
Fast deformable structure regression tracking
Authors: Yang Xian , Wang Shoujue
Published: October 2015

Visual object tracking is a challenging task because designing an effective and efficient appearance model is difficult. Current online tracking algorithms treat tracking as a classification task and use labelled samples to update appearance model. However, it is not clear to evaluate instance confidence belongs to the object. In this study, the authors propose a simple and efficient tracking algorithm with a deformable structure appearance. In their method, model updates with continuous labelled samples which are dense sampling. To improve the accuracy, they introduce a coupled‐layer regression model which prevents negative background from impacting on the model learning rather than traditional classification. The proposed deformable structure regression tracker runs in real time and performs favourably against state‐of‐the‐art trackers on various challenging sequences.
Efficient image features selection and weighting for fundamental matrix estimation
Authors: Wang Liqiang , Liu Zhen , Zhang Zhonghua
Published: October 2015

In computer vision, it is a challenge to compute the relationship of multiple views from scene images. The view relationship can be obtained from the fundamental matrix. Thus, it is very important to compute an accurate fundamental matrix from unevenly distributed features in complex scene images. This study proposes a robust method to estimate the fundamental matrix from corresponding images. First, the authors introduce how to find matched features from scene images efficiently. The epipolar geometry can restrict the point correspondences to the polar line, but cannot cope with the false points lying on the line. To eliminate such mismatches, the authors present an affine constraint which can also merge the uniform regions produced by mean‐shift segmentation. Second, inspired by the success of random sample consensus, the authors moderately improve the weighting function based on M‐estimator to increase the accuracy of the fundamental matrix estimation. Experimental results on simulated data and real images show these works are efficient for estimating fundamental matrix. The authors also evaluated the accuracy of their method on computing the external parameters of two cameras. The result shows that this method obtains comparable performance to the more sophisticated calibration method.
Variable active antenna spatial modulation
Authors: Osman Onur
Published: October 2015

In this study, variable active antenna spatial modulation (VASM) technique, which allows the selection of any number of antennas (but not a constant number of active antennas) to transmit a symbol at the same signalling interval, is presented. In the first step of the development of VASM, antenna selection method is determined to use the minimum number of transmit antennas. Complexity analysis of maximum likelihood decoder is given for the new scheme. In the second step, to reduce the correlation effect, a novel antenna selection method called VASM improved (VASMi) that minimises the pairwise error probability is introduced for exponentially correlated channels. For 6, 8, and 10 bit/s/Hz spectral efficiencies, bit error rates are obtained and compared with spatial modulation (SM) and generalised SM (GSM) for different antenna and signal constellation configurations. VASMi outperforms SM and GSM in both uncorrelated and exponentially correlated multiple‐input multiple‐output channels for similar antenna configurations.
Pattern diversity antenna with high‐temperature tolerance for body area networks
Authors: Faiz Alam Muhammad , Gogosh Nayab , Rehman Abdul , Shafique Muhammad Farhan , Poussot Benoit , Laheurte Jean Marc
Published: October 2015

A high‐temperature tolerant pattern diversity antenna is presented for body wearable applications in hostile conditions. The proposed system consists of a dielectric resonator antenna (DRA) placed at the centre of a slot loop antenna. The combination yields pattern diversity with broadside and endfire radiation patterns from slot loop and DRAs, respectively. The antenna system offers common bandwidth of 4.95% with port isolation of better than 13 dB at 2.4 GHz. The thermal characteristics of antenna have been studied for high‐temperature operation and no discernible change in the radiation behaviour is noted. The antenna undergoes 2% resonant frequency shift when operated at elevated temperature. The antenna diversity has been measured for three on‐body communication channels. The antenna offers 9.5 dB diversity gain in a pure non‐line‐of‐sight channel surrounded by a rich fading environment subjected to the selection combining scheme. The antenna has dimensions of 0.4λo × 0.4λo × 0.1λo.
An Update on Familial Hyperaldosteronism
Authors: Korah H. E. , Scholl U. I.
Published: October 2015

Familial forms of primary aldosteronism have been suggested to account for up to
6% of cases in referral centers. For many years, the genetics of familial
hyperaldosteronism remained unknown, with the notable exception of
glucocorticoid-remediable aldosteronism, due to unequal crossing over and
formation of a chimeric 11β-hydroxylase/aldosterone synthase gene. Over the past
5 years, mutations in 3 additional genes have been shown to cause familial forms
of primary aldosteronism. Gain-of-function heterozygous germline mutations in
KCNJ5, which encodes an inward rectifier potassium channel, cause
autosomal dominant syndromes of PA and hypertension with or without adrenal
hyperplasia. Germline mutations in CACNA1D, which codes for an L-type
calcium channel, have so far only been found in 2 cases with a syndrome of
primary aldosteronism, seizures, and neurologic abnormalities. Both KCNJ5
and CACNA1D mutations in familial hyperaldosteronism were only discovered
following identification of similar or identical somatic mutations in
aldosterone-producing adenomas. In contrast, a recent exome sequencing study
identified germline mutations in CACNA1H (a T-type calcium channel),
previously undescribed in adenomas, in 5 unrelated families with early-onset
primary aldosteronism and hypertension, without any additional shared symptoms.
Future exome or genome sequencing studies are expected to shed light on the
genetic basis of many cases of familial hyperaldosteronism that remain
unexplained.
Sub-50 nm metrology on extreme ultra violet chemically amplified resist—A systematic assessment
Authors: Maas D. J. , Fliervoet T. , Herfst R. , van Veldhoven E. , Meessen J. , Vaenkatesan V. , Sadeghian H.
Published: October 2015

With lithographic patterning dimensions decreasing well below 50 nm, it is of high importance to understand metrology at such small scales. This paper presents results obtained from dense arrays of contact holes (CHs) with various Critical Dimension (CD) between 15 and 50 nm, as patterned in a chemically amplified resist using an ASML EUV scanner and measured at ASML and TNO. To determine the differences between various (local) CD metrology techniques, we conducted an experiment using optical scatterometry, CD-Scanning Electron Microscopy (CD-SEM), Helium ion Microscopy (HIM), and Atomic Force Microscopy (AFM). CD-SEM requires advanced beam scan strategies to mitigate sample charging; the other tools did not need that. We discuss the observed main similarities and differences between the various techniques. To this end, we assessed the spatial frequency content in the raw images for SEM, HIM, and AFM. HIM and AFM resolve the highest spatial frequencies, which are attributed to the more localized probe-sample interaction for these techniques. Furthermore, the SEM, HIM, and AFM waveforms are analyzed in detail. All techniques show good mutual correlation, albeit the reported CD values systematically differ significantly. HIM systematically reports a 25% higher CD uniformity number than CD-SEM for the same arrays of CHs, probably because HIM has a higher resolution than the CD-SEM used in this assessment. A significant speed boost for HIM and AFM is required before these techniques are to serve the demanding industrial metrology applications like optical critical dimension and CD-SEM do nowadays.
A sound idea: Manipulating domain walls in magnetic nanowires using surface acoustic waves
Authors: Dean J. , Bryan M. T. , Cooper J. D. , Virbule A. , Cunningham J. E. , Hayward T. J.
Published: October 2015

We propose a method of pinning and propagating domain walls in artificial multiferroic nanowires using electrically induced surface acoustic waves. Using finite-element micromagnetic simulations and 1D semi-analytical modelling, we demonstrate how a pair of interdigitated acoustic transducers can remotely induce an array of attractive domain wall pinning sites by forming a standing stress/strain wave along a nanowire's length. Shifts in the frequencies of the surface acoustic waves allow multiple domain walls to be synchronously transported at speeds up to 50 ms−1. Our study lays the foundation for energy-efficient domain wall devices that exploit the low propagation losses of surface acoustic waves to precisely manipulate large numbers of data bits.
Thermoelectric transport coefficients in mono-layer MoS2 and WSe2: Role of substrate, interface phonons, plasmon, and dynamic screening
Authors: Ghosh Krishnendu , Singisetti Uttam
Published: October 2015

The thermoelectric transport coefficients of electrons in two recently emerged transition metal di-chalcogenides (TMD), MoS2 and WSe2, are calculated by solving Boltzmann transport equation using Rode's iterative technique in the diffusive transport regime and the coupled current (electrical and heat) equations. Scattering from remote phonons along with the hybridization of TMD plasmon with remote phonon modes and dynamic screening under linear polarization response are investigated in TMDs sitting on a dielectric environment. The transport coefficients are obtained for a varying range of temperature and doping density for three different types of substrates—SiO2, Al2O3, and HfO2. The Seebeck co-efficient for MoS2 and WSe2 is found to be higher than 3D semiconductors even with diffusive transport. The electronic thermal conductivity is found to be low, however, the thermoelectric figure of merit is limited by the high phonon thermal conductivity. It is found that judicious selection of a dielectric environment based on temperature of operation and carrier density is crucial to optimize the thermoelectric performance of TMD materials.
A compact E × B filter: A multi-collector cycloidal focusing mass spectrometer
Authors: Blase Ryan C. , Miller Greg , Westlake Joseph , Brockwell Tim , Ostrom Nathaniel , Ostrom Peggy H. , Waite J. Hunter
Published: October 2015

A compact E × B mass spectrometer is presented. The mass spectrometer presented is termed a “perfect focus” mass spectrometer as the resolution of the device is independent of both the initial direction and energy of the ions (spatial and energy independent). The mass spectrometer is small in size (∼10.7 in.3) and weight (∼2 kg), making it an attractive candidate for portability when using small, permanent magnets. A multi-collector Faraday cup design allows for the detection of multiple ion beams in discrete collectors simultaneously; providing the opportunity for isotope ratio monitoring. The mass resolution of the device is around 400 through narrow collector slits and the sensitivity of the device follows expected theoretical calculations of the ion current produced in the electron impact ion source. Example mass spectra obtained from the cycloidal focusing mass spectrometer are presented as well as information on mass discrimination based on instrumental parameters and isotope ratio monitoring of certain ion signals in separate Faraday cups.
Graphene-enhanced intermolecular interaction at interface between copper- and cobalt-phthalocyanines
Authors: Dou Wei-Dong , Huang Shu-Ping , Lee Chun-Sing
Published: October 2015

Interfacial electronic structures of copper-phthalocyanine (CuPc), cobalt-phthalocyanine (CoPc), and graphene were investigated experimentally by using photoelectron spectroscopy. While the CuPc/graphene interface shows flat band structure and negligible interfacial dipole indicating quite weak molecule-substrate interaction, the CuPc/CoPc/graphene interface shows a large interfacial dipole and obvious energy level bending. Controlled experiments ruled out possible influences from the change in film structure of CuPc and pure π–π interaction between CoPc and CuPc. Analysis based on X-ray photoelectron spectroscopy and density functional theory reveals that the decrease in the work function for the CuPc/CoPc/graphene system is induced by the intermolecular interaction between CuPc and CoPc which is enhanced owning to the peculiar electronic properties at the CoPc-graphene interface.
Nanoindentation study of the mechanical behavior of TiO2 nanotube arrays
Authors: Xu Y. N. , Liu M. N. , Wang M. C. , Oloyede A. , Bell J. M. , Yan C.
Published: October 2015

Titanium dioxide (TiO2) nanotube arrays are attracting increasing attention for use in solar cells, lithium-ion batteries, and biomedical implants. To take full advantage of their unique physical properties, such arrays need to maintain adequate mechanical integrity in applications. However, the mechanical performance of TiO2 nanotube arrays is not well understood. In this work, we investigate the deformation and failure of TiO2 nanotube arrays using the nanoindentation technique. We found that the load–displacement response of the arrays strongly depends on the indentation depth and indenter shape. Substrate-independent elastic modulus and hardness can be obtained when the indentation depth is less than 2.5% of the array height. The deformation mechanisms of TiO2 nanotube arrays by Berkovich and conical indenters are closely associated with the densification of TiO2 nanotubes under compression. A theoretical model for deformation of the arrays under a large-radius conical indenter is also proposed.
Methane dissociation on Ni(111): A fifteen-dimensional potential energy surface using neural network method
Authors: Shen Xiangjian , Chen Jun , Zhang Zhaojun , Shao Kejie , Zhang Dong H.
Published: October 2015

In the present work, we develop a highly accurate, fifteen-dimensional potential energy surface (PES) of CH4 interacting on a rigid flat Ni(111) surface with the methodology of neural network (NN) fit to a database consisted of about 194 208 ab initio density functional theory (DFT) energy points. Some careful tests of the accuracy of the fitting PES are given through the descriptions of the fitting quality, vibrational spectrum of CH4 in vacuum, transition state (TS) geometries as well as the activation barriers. Using a 25-60-60-1 NN structure, we obtain one of the best PESs with the least root mean square errors: 10.11 meV for the entrance region and 17.00 meV for the interaction and product regions. Our PES can reproduce the DFT results very well in particular for the important TS structures. Furthermore, we present the sticking probability S0 of ground state CH4 at the experimental surface temperature using some sudden approximations by Jackson’s group. An in-depth explanation is given for the underestimated sticking probability.
Asymmetric energy flow in liquid alkylbenzenes: A computational study
Authors: Leitner David M. , Pandey Hari Datt
Published: October 2015

Ultrafast IR-Raman experiments on substituted benzenes [B. C. Pein et al., J. Phys. Chem. B 117, 10898–10904 (2013)] reveal that energy can flow more efficiently in one direction along a molecule than in others. We carry out a computational study of energy flow in the three alkyl benzenes, toluene, isopropylbenzene, and t-butylbenzene, studied in these experiments, and find an asymmetry in the flow of vibrational energy between the two chemical groups of the molecule due to quantum mechanical vibrational relaxation bottlenecks, which give rise to a preferred direction of energy flow. We compare energy flow computed for all modes of the three alkylbenzenes over the relaxation time into the liquid with energy flow through the subset of modes monitored in the time-resolved Raman experiments and find qualitatively similar results when using the subset compared to all the modes.
Acoustic streaming, fluid mixing, and particle transport by a Gaussian ultrasound beam in a cylindrical container
Authors: Marshall Jeffrey S. , Wu Junru
Published: October 2015

A computational study is reported of the acoustic streaming flow field generated by a Gaussian ultrasound beam propagating normally toward the end wall of a cylindrical container. Particular focus is given to examining the effectiveness of the acoustic streaming flow for fluid mixing within the container, for deposition of particles in suspension onto the bottom surface, and for particle suspension from the bottom surface back into the flow field. The flow field is assumed to be axisymmetric with the ultrasound transducer oriented parallel to the cylinder axis and normal to the bottom surface of the container, which we refer to as the impingement surface. Reflection of the sound from the impingement surface and sound absorption within the material at the container bottom are both accounted for in the computation. The computation also accounts for thermal buoyancy force due to ultrasonic heating of the impingement surface, but over the time period considered in the current simulations, the flow is found to be dominated by the acoustic streaming force, with only moderate effect of buoyancy force.
Physical processes of driven magnetic reconnection in collisionless plasmas: Zero guide field case
Authors: Cheng C. Z. , Inoue S. , Ono Y. , Horiuchi R.
Published: October 2015

The key physical processes of the electron and ion dynamics, the structure of the electric and magnetic fields, and how particles gain energy in the driven magnetic reconnection in collisionless plasmas for the zero guide field case are presented. The key kinetic physics is the decoupling of electron and ion dynamics around the magnetic reconnection region, where the magnetic field is reversed and the electron and ion orbits are meandering, and around the separatrix region, where electrons move mainly along the field line and ions move mainly across the field line. The decoupling of the electron and ion dynamics causes charge separation to produce a pair of in-plane bipolar converging electrostatic electric field (E→es) pointing toward the neutral sheet in the magnetic field reversal region and the monopolar E→es around the separatrix region. A pair of electron jets emanating from the reconnection current layer generate the quadrupole out-of-plane magnetic field, which causes the parallel electric field (E→||) from E→ind to accelerate particles along the magnetic field. We explain the electron and ion dynamics and their velocity distributions and flow structures during the time-dependent driven reconnection as they move from the upstream to the downstream. In particular, we address the following key physics issues: (1) the decoupling of electron and ion dynamics due to meandering orbits around the field reversal region and the generation of a pair of converging bipolar electrostatic electric field (E→es) around the reconnection region; (2) the slowdown of electron and ion inflow velocities due to acceleration/deceleration of electrons and ions by E→es as they move across the neutral sheet; (3) how the reconnection current layer is enhanced and how the orbit meandering particles are accelerated inside the reconnection region by E→ind; (4) why the electron outflow velocity from the reconnection region reaches super-Alfvenic speed and the ion outflow velocity reaches Alfvenic speed; (5) how the quadrupole magnetic field is produced and how E→|| is produced; (6) how electrons and ions are accelerated by E→|| around the separatrix region; (7) why electrons have a flat-top parallel velocity distribution in the upstream just outside the reconnection region as observed in the magnetotail; (8) how electron and ion dynamics decouple and how the monopolar electrostatic electric field is produced around the separatrix region; (9) how ions gain energy as they move across the separatrix region into the downstream and how the ion velocity distribution is thermalized in the far downstream; and (10) how electrons move across the separatrix region and in the downstream and how the electron velocity distribution is thermalized in the far downstream. Finally, the main energy source for driving magnetic reconnection and particle acceleration/heating is the inductive electric field, which accelerates both electrons and ions around the reconnection current layer and separatrix regions.
Semiclassical Green’s functions and an instanton formulation of electron-transfer rates in the nonadiabatic limit
Authors: Richardson Jeremy O. , Bauer Rainer , Thoss Michael
Published: October 2015

We present semiclassical approximations to Green’s functions of multidimensional systems, extending Gutzwiller’s work to the classically forbidden region. Based on steepest-descent integrals over these functions, we derive an instanton method for computing the rate of nonadiabatic reactions, such as electron transfer, in the weak-coupling limit, where Fermi’s golden-rule can be employed. This generalizes Marcus theory to systems for which the environment free-energy curves are not harmonic and where nuclear tunnelling plays a role. The derivation avoids using the Im F method or short-time approximations to real-time correlation functions. A clear physical interpretation of the nuclear tunnelling processes involved in an electron-transfer reaction is thus provided. In Paper II [J. O. Richardson, J. Chem. Phys. 143, 134116 (2015)], we discuss numerical evaluation of the formulae.
Ring-polymer instanton theory of electron transfer in the nonadiabatic limit
Authors: Richardson Jeremy O.
Published: October 2015

We take the golden-rule instanton method derived in the previous paper [J. O. Richardson, R. Bauer, and M. Thoss, J. Chem. Phys. 143, 134115 (2015)] and reformulate it using a ring-polymer instanton approach. This gives equations which can be used to compute the rates of electron-transfer reactions in the nonadiabatic (golden-rule) limit numerically within a semiclassical approximation. The multidimensional ring-polymer instanton trajectories are obtained efficiently by minimization of the action. In this form, comparison with Wolynes’ quantum instanton method [P. G. Wolynes, J. Chem. Phys. 87, 6559 (1987)] is possible and we show that our semiclassical approach is the steepest-descent limit of this method. We discuss advantages and disadvantages of both methods and give examples of where the new approach is more accurate.
Projected metastable Markov processes and their estimation with observable operator models
Authors: Wu Hao , Prinz Jan-Hendrik , Noé Frank
Published: October 2015

The determination of kinetics of high-dimensional dynamical systems, such as macromolecules, polymers, or spin systems, is a difficult and generally unsolved problem — both in simulation, where the optimal reaction coordinate(s) are generally unknown and are difficult to compute, and in experimental measurements, where only specific coordinates are observable. Markov models, or Markov state models, are widely used but suffer from the fact that the dynamics on a coarsely discretized state spaced are no longer Markovian, even if the dynamics in the full phase space are. The recently proposed projected Markov models (PMMs) are a formulation that provides a description of the kinetics on a low-dimensional projection without making the Markovianity assumption. However, as yet no general way of estimating PMMs from data has been available. Here, we show that the observed dynamics of a PMM can be exactly described by an observable operator model (OOM) and derive a PMM estimator based on the OOM learning.
Reversible electrochemical modulation of the superconducting transition temperature of LiTi2O4 ultrathin films by ionic liquid gating
Authors: Maruyama S. , Shin J. , Zhang X. , Suchoski R. , Yasui S. , Jin K. , Greene R. L. , Takeuchi I.
Published: October 2015

We demonstrate in situ modulation of the superconducting transition temperature (Tc) of LiTi2O4 thin films by ionic liquid gating. 15 nm thick LiTi2O4 thin films grown on MgAl2O4 substrates with the pristine Tc of 11.5 K was patterned into electric double-layer transistor devices for gating using ionic liquid with or without Li+ ions. The Tc of the LiTi2O4 thin film was found to decrease with a negative gate voltage for gating with either pure ionic liquid or Li+ containing ionic liquid. On the other hand, the recovery of Tc is observed at a positive gate voltage only for gating with the Li+ containing ionic liquid. The present observation suggests the possibility of reversible electrochemical modulation of superconducting properties by lithiation and delithiation.
Research Update: Direct conversion of amorphous carbon into diamond at ambient pressures and temperatures in air
Authors: Narayan Jagdish , Bhaumik Anagh
Published: October 2015

We report on fundamental discovery of conversion of amorphous carbon into diamond by irradiating amorphous carbon films with nanosecond lasers at room-temperature in air at atmospheric pressure. We can create diamond in the form of nanodiamond (size range <100 nm) and microdiamond (>100 nm). Nanosecond laser pulses are used to melt amorphous diamondlike carbon and create a highly undercooled state, from which various forms of diamond can be formed upon cooling. The quenching from the super undercooled state results in nucleation of nanodiamond. It is found that microdiamonds grow out of highly undercooled state of carbon, with nanodiamond acting as seed crystals.
In-situ characterization of the optical and electronic properties in GeTe and GaSb thin films
Authors: Velea A. , Socol G. , Popescu M. , Galca A. C.
Published: October 2015

GeTe and GaSb thin films obtained by pulsed laser deposition were investigated by spectroscopic ellipsometry at controlled temperatures. The GeTe films were fully amorphous, while the GaSb films were partially crystalized in the as-deposited state. The Tauc-Lorentz model was employed to fit the experimental data. From the temperature study of the optical constants, it was observed the crystallization in the 150–160 °C range of GeTe amorphous films and between 230 and 240 °C of GaSb amorphous phase. A second transition in the resonance energy and the broadening parameter of the Lorentz oscillator was observed due to the crystallization of Sb after 250 °C. The temperatures of 85 °C and 130 °C are noticed as the start of the relaxation of the amorphous GeTe phase and as-deposited GaSb. The peaks of the imaginary part of the dielectric function red shifted after the phase change, while the variation with temperature of the crystalline phase follows the Varshni law. The electron-phonon coupling constants are 2.88 and 1.64 for c-GeTe and c-GaSb, respectively. An optical contrast up to 60% was obtained for GeTe films and a maximum value of 7.5% is revealed in the case GaSb, which is altered by the partial crystallinity of the as-deposited films.
Noncontact Casimir rack and pinion as an excitable system
Authors: Etesami Zahra , Miri MirFaez
Published: October 2015

We study the influence of thermal noise on the rack and pinion coupled by the lateral Casimir force. The pinion position versus time exhibits a sequence of spikes. We identify the Casimir machine as an excitable system equivalent to the Adler system. We show that the interspike time distribution can be analyzed to access the Casimir and friction forces. The inherent susceptibility of nanomachines to the thermal noise can be utilized to measure weak Casimir forces.