bluuebunny/crossref_metadata_2025 huggingface dataset:
4 × 2 Tbit/s superchannel self‐coherent transmission based on carrier tracking and expanding
Authors: Xiao Xiao , Yang Qi , Yi Xingwen , Yang Chao , Li Zhaohui , He Zhixue , Luo Ming , Gui Tao , Li Chao , Zhang Xu , Xue Daojun , Hu Rong , Yu Shaohua
Published: January 2014

A novel superchannel transmission scheme is proposed where an optical comb source is used to carry the multiband signal and one subcarrier is reserved for regeneration as a local oscillator at the receiver end. By combining carrier tracking and carrier expanding, a 4 × 2 Tbit/s superchannel wavelength division multiplexed self‐coherent transmission over a 320 km standard single mode fibre has been successfully demonstrated.
Learned geometric features of 3D range data for human and tree recognition
Authors: Cho Kuk , Kim Chunghoon , Baeg Seung‐Ho , Park Sangdeok
Published: January 2014

A new method of obtaining geometric features of three‐dimensional range data for human and tree recognition in an off‐road environment is described. The learning algorithm AdaBoost is used to select a set of discriminative features from a very large set of potential geometric features. The proposed geometric feature can be considered as a generalisation of the geometric feature used in previous studies. The experimental results for human and tree recognition show that the proposed method outperforms the other methods.
Feasibility test of deformable BAN electrodes in ear canal
Authors: Arman Woo S.H.
Published: January 2014

Implantable and portable medical devices have attracted much interest in recent years and the interconnections of these devices have become an important issue. One interconnection method is the use of the body access network (BAN) that does not need high power consumption as conventional radio frequency communication methods. Previous studies of the BAN have focused on measuring between the chest, wrist and other surface parts of the skin which are easily accessible with conventional electrodes. Deformable BAN electrodes are implemented to study the effectiveness of BAN communications in the ear canal. Conventional earphones and Bluetooth devices can easily access the ear canal and could be used for the BAN communication channel. The experimental results show various transmission loss among the ear canal, the wrist and the chest. The lowest attenuation showed as 23 dB at 34 MHz.
Channel estimation and symbol detection for OFDM systems using data‐nulling superimposed pilots
Authors: Dou Gaoqi , He Chunquan , Li Congying , Gao Jun
Published: January 2014

A novel data‐nulling superimposed pilot scheme for orthogonal frequency division multiplexing (OFDM) systems is proposed, where the input data vector is spread over all the subcarriers by a precoding matrix and then nulled at certain subcarriers for the insertion of training pilots. This method avoids the loss of the data rate for frequency‐division multiplexed pilots, but results in the distortion of input data. To mitigate the distortion introduced by the nulling operation, a simple iterative reconstruction scheme is used to improve the detection performance.
Feedback interval for link adaptation in TDMA‐based single‐carrier VHF narrowband mobile ad‐hoc networks
Authors: Helmle S. , Dehm M. , Kuhn M. , Lieckfeldt D. , Pesch D.
Published: January 2014

The impact of a link adaptation feedback interval on user net throughput for time division multiple access (TDMA)‐based single‐carrier very high frequency (VHF) narrowband mobile ad‐hoc networks (MANETs) is investigated. Specifically for the narrowband MANETs optimisation of the signalling overhead is one of the major challenges. Reducing the overhead means that more user data can be transmitted; however, the quality of channel quality feedback information will be lower, resulting in potentially inaccurate link adaptation decisions. The results from Monte Carlo computer simulation show that a global maximum for the throughput with respect to interval exists. The achievable throughput, however, strongly depends on the user mobility pattern.
Optimum antenna combining in presence of TX leakage
Authors: Park Chester Sungchung , Kim Jintae
Published: January 2014

Optimum antenna combining is utilised to cope with the transmitter (TX) leakage issue encountered in carrier aggregation. By assuming the transmission of pilot symbols and exploiting the structural information of the noise‐plus‐interference covariance, the maximum likelihood covariance estimation is mathematically derived. The simulation results verify that the proposed antenna combining with the structured covariance estimation provides a noticeable performance gain in the presence of TX leakage.
Power allocation for secure OFDMA systems with wireless information and power transfer
Authors: Huang Xiaobin , Li Quanzhong , Zhang Qi , Qin Jiayin
Published: January 2014

For simultaneous wireless information and power transfer (SWIPT), secure transmission is an important issue. The power allocation problem is investigated to maximise the achievable secrecy rate in a downlink orthogonal frequency division multiple access system with a power splitting SWIPT scheme. Unlike the traditional wireless communication systems, it is assumed that the legitimate receivers have no energy storage capability. The legitimate receivers harvest the energy from the received signals by using a power splitting scheme to meet the circuit‐power constraint for information decoding. The problem is formulated as a power allocation optimisation problem under the transmit power constraint and the energy harvesting constraint which is solvable. It is shown from simulations that the proposed optimal power allocation scheme outperforms the conventional uniform power allocation scheme.
SAR‐based delta–sigma modulator using single‐bit shared‐DAC
Authors: Reyhani S.Z. , Hashemipour O.
Published: January 2014

A new single‐bit ΔΣ modulator based on multi‐bit quantisation and a successive approximation (SA) algorithm with improved output swing due to a reduced quantisation noise power is presented. Although this structure maintains the linearity of the single‐bit digital‐to‐analogue converter (DAC), it also removes the requirement for a high slew rate operational amplifier. Hence, the modulator dissipates less power.
Digital shape compactness measure by means of perimeter ratios
Authors: Santiago‐Montero R. , López‐Morales M.A. , Sossa J.H.
Published: January 2014

A goodness compactness measure is necessary in computer medical diagnosis, shape analysis and computer vision processes. A compactness measure called the normalised E‐factor (NEF) is introduced. It is shown that this measure is simple and robust to translations, rotations and scale changes and that it satisfies the set of criteria for a good compactness measure. Through a series of experiments it is shown that the normalised E‐factor is useful for shape description, measuring digital compactness with or without holes and that it overcomes some drawbacks that are present in the classical and normalised discrete compactness measures.
Extremely compact phase delay line with CTSRR loaded transmission line
Authors: Sajin J.S. , Praveen G. , Habiba H.U. , Rao P.H.
Published: January 2014

Phase delay characteristics of the complementary triangular split ring resonator (CTSRR) loaded transmission line with capacitive stubs are presented. The phase responses of a reference microstrip transmission line and a transmission line with capacitive stubs, loaded with the CTSRR on the ground plane, are compared. The practical results show that the CTSRR loaded transmission line provides four times more phase delay when compared with a reference transmission line, and thus the proposed configuration provides a 76% transmission line length reduction.
Electrostatic discharge protection devices with series connection using distributed cell‐based diodes
Authors: Son Minoh , Park Changkun
Published: January 2014

A series electrostatic discharge (ESD) diode structure is proposed to minimise the degradation induced by thermal interaction between series connected diodes. The proposed series diode is constructed using a distributed cell‐based ESD diode. To verify the feasibility of the proposed structure, single and series diodes are designed using the typical and the proposed structures. From the experimental results, it is proved that the ESD survival levels of the proposed series diode are nearly identical to those of the single diode, unlike the case of typical series diodes.
Compact square spiral printed antenna
Authors: Wei Heng , Lin Min , Xiang Yang
Published: January 2014

A novel compact printed antenna with a spiral winding and a loop feed is proposed. After optimising the design parameters, the prototype of the antenna with a small electrical size of 0.043λc × 0.043λc × 0.001λc is fabricated. It is shown that a central frequency as low as 425.9 MHz can be achieved without any additional matching networks, and a good omnidirectional radiation pattern similar to the dipole antenna is obtained.
Focusing forward‐looking bistatic SAR data with chirp scaling
Authors: Qi C.D. , Shi X.M. , Bian M.M. , Xue Y.J.
Published: January 2014

A bistatic chirp scaling algorithm (CSA) is presented to process the forward‐looking bistatic synthetic aperture radar (FL‐BiSAR) data. First, the double‐square‐root equation in the general bistatic range model can be simplified to a square‐root equation, when the size of the scene is small enough. Based on the model, the range Doppler spectrum is derived. Then, a CSA is obtained. The range model is proved to be an effective proxy by a simulation.
Quality of Transfusion Products in Blood Banking
Authors: Franchini Massimo , Capuzzo Enrico , Turdo Rosalia , Glingani Claudia
Published: January 2014

The primary goal in transfusion medicine and cellular therapies is to promote high standards of quality and produce ever safer and more efficacious products. The establishment of a transfusion service quality management system, which includes several organizational structures, responsibilities, policies, processes, procedures, and resources, is now mandatory and widely regulated worldwide. In this review, we summarize the current knowledge on the quality system in transfusion medicine as applied to the production of blood components, including red blood cells, platelets, and fresh frozen plasma.
A high intensity 200 mA proton source for the FRANZ-Project (Frankfurt-Neutron-Source at the Stern-Gerlach-Center)
Authors: Schweizer W. , Ratzinger U. , Klump B. , Volk K.
Published: January 2014

At the University of Frankfurt a high current proton source has been developed and tested for the FRANZ-Project [U. Ratzinger, L. P. Chau, O. Meusel, A. Schempp, K. Volk, M. Heil, F. Käppeler, and R. Stieglitz, “Intense pulsed neutron source FRANZ in the 1–500 keV range,” ICANS-XVIII Proceedings, Dongguan, April 2007, p. 210]. The ion source is a filament driven arc discharge ion source. The new design consists of a plasma generator, equipped with a filter magnet to produce nearly pure proton beams (92 %), and a compact triode extraction system. The beam current density has been enhanced up to 521 mA/cm2. Using an emission opening radius of 4 mm, a proton beam current of 240 mA at 50 keV beam energy in continuous wave mode (cw) has been extracted. This paper will present the current status of the proton source including experimental results of detailed investigations of the beam composition in dependence of different plasma parameters. Both, cw and pulsed mode were studied. Furthermore, the performance of the ion source was studied with deuterium as working gas.
Cross-linked structure of network evolution
Authors: Bassett Danielle S. , Wymbs Nicholas F. , Porter Mason A. , Mucha Peter J. , Grafton Scott T.
Published: January 2014

We study the temporal co-variation of network co-evolution via the cross-link structure of networks, for which we take advantage of the formalism of hypergraphs to map cross-link structures back to network nodes. We investigate two sets of temporal network data in detail. In a network of coupled nonlinear oscillators, hyperedges that consist of network edges with temporally co-varying weights uncover the driving co-evolution patterns of edge weight dynamics both within and between oscillator communities. In the human brain, networks that represent temporal changes in brain activity during learning exhibit early co-evolution that then settles down with practice. Subsequent decreases in hyperedge size are consistent with emergence of an autonomous subgraph whose dynamics no longer depends on other parts of the network. Our results on real and synthetic networks give a poignant demonstration of the ability of cross-link structure to uncover unexpected co-evolution attributes in both real and synthetic dynamical systems. This, in turn, illustrates the utility of analyzing cross-links for investigating the structure of temporal networks.
Dramatic changes in electronic structure revealed by fractionally charged nuclei
Authors: Cohen Aron J. , Mori-Sánchez Paula
Published: January 2014

Discontinuous changes in the electronic structure upon infinitesimal changes to the Hamiltonian are demonstrated. These are revealed in one and two electron molecular systems by full configuration interaction (FCI) calculations when the realm of the nuclear charge is extended to be fractional. FCI electron densities in these systems show dramatic changes in real space and illustrate the transfer, hopping, and removal of electrons. This is due to the particle nature of electrons seen in stretched systems and is a manifestation of an energy derivative discontinuity at constant number of electrons. Dramatic errors of density functional theory densities are seen in real space as this physics is missing from currently used approximations. The movements of electrons in these simple systems encapsulate those in real physical processes, from chemical reactions to electron transport and pose a great challenge for the development of new electronic structure methods.
Magnetic properties of Ni substituted Y-type barium ferrite
Authors: Won Mi Hee , Kim Chul Sung
Published: January 2014

Y-type barium hexaferrite is attractive material for various applications, such as high frequency antennas and RF devices, because of its interesting magnetic properties. Especially, Ni substituted Y- type hexaferrites have higher magnetic ordering temperature than other Y-type. We have investigated macroscopic and microscopic properties of Y-type barium hexaferrite. Ba2Co2−xNixFe12O22 (x = 0, 0.5, 1.0, 1.5, and 2.0) samples are prepared by solid-state reaction method and studied by X-ray diffraction (XRD), vibrating sample magnetometer, and Mössbauer spectroscopy, as well as a network analyzer for high frequency characteristics. The XRD pattern is analyzed by Rietveld refinement method and confirms the hexagonal structure with R-3m. The hysteresis curve shows ferrimagnetic behavior. Saturation magnetization (Ms) decreases with Ni contents. Ni2+, which preferentially occupies the octahedral site with up-spin sub-lattice, has smaller spin value S of 1 than Co2+ having S = 3/2. The zero-field-cooled (ZFC) measurement of Ba2Co1.5Ni0.5Fe12O22 shows that Curie and spin transition temperatures are found to be 718 K and 209 K, respectively. The Curie temperature TC is increased with Ni contents, while TS is decreased with Ni. The Mössbauer spectra were measured at various temperatures and fitted by using a least-squares method with six sextet of six Lorentzian lines for Fe sites, corresponding to the 3bVI, 6cIV*, 6cVI, 18hVI, 6cIV, and 3aIV sites at below TC. From Mössbauer measurements, we confirmed the spin state of Fe ion to be Fe3+ and obtained the isomer shift (δ), magnetic hyperfine field (Hhf), and the occupancy ratio of Fe ions at six sub-lattices. The complex permeability and permittivity are measured between 100 MHz and 4 GHz, suggesting that Y-type barium hexaferrite is promising for antenna applications in UHF band.
A practical perspective on the implementation of hyperdynamics for accelerated simulation
Authors: Kim Woo Kyun , Falk Michael L.
Published: January 2014

Consideration is given to several practical issues arising during the implementation of hyperdynamics, a methodology that extends the time scale of the conventional molecular dynamics simulation potentially by orders of magnitude. First, the methodology is reformulated in terms of the transition rate based on the buffer region approach (buffer rate), which can describe transitions in more general contexts than the transition state theory (TST). It will be shown that hyperdynamics can exactly preserve the buffer rate as well as the TST rate, which broadens the scope of the method. Next, the originally proposed scheme to compute the boost factor on-the-fly is reviewed and some alternative methods, one of which uses the umbrella sampling method, are presented. Finally, the methodology is validated in the context of a 1-dimensional example potential and a 3-dimensional simulation of the motion of an atomic force microscope tip moving along a surface.
Twisted 3D $\mathcal {N}=4$N=4 supersymmetric YM on deformed $\mathbb {A}_{3}^{\ast }$A3* lattice
Authors: Saidi El Hassan
Published: January 2014

We study a class of twisted 3D \documentclass[12pt]{minimal}\begin{document}$\mathcal {N}=4$\end{document}N=4 supersymmetric Yang-Mills (SYM) theory on particular 3-dimensional lattice \documentclass[12pt]{minimal}\begin{document}$\mathbb {L}_{3D}$\end{document}L3D formally denoted as \documentclass[12pt]{minimal}\begin{document}$\mathcal {L}_{3D}^{su_{3}\times u_{1}}$\end{document}L3Dsu3×u1 and given by non-trivial fibration \documentclass[12pt]{minimal}\begin{document}$\mathcal {L}_{1D}^{u_{1}}\times \mathcal {L}_{2D}^{su_{3}}$\end{document}L1Du1×L2Dsu3 with base \documentclass[12pt]{minimal}\begin{document}$\mathcal {L}_{2D}^{su_{3}}=\mathbb {A}_{2}^{\ast }$\end{document}L2Dsu3=A2*, the weight lattice of SU(3). We first, develop the twisted 3D \documentclass[12pt]{minimal}\begin{document}$\mathcal {N}=4$\end{document}N=4 SYM in continuum by using superspace method where the scalar supercharge Q is manifestly exhibited. Then, we show how to engineer the 3D lattice \documentclass[12pt]{minimal}\begin{document}$\mathcal {L}_{3D}^{su_{3}\times u_{1}}$\end{document}L3Dsu3×u1 that host this theory. After that we build the lattice action \documentclass[12pt]{minimal}\begin{document}$\mathcal {S}_{latt}$\end{document}Slatt invariant under the following three points: (i) U(N) gauge invariance, (ii) BRST symmetry, (iii) the \documentclass[12pt]{minimal}\begin{document}$\mathbb {S} _{3}$\end{document}S3 point group symmetry of \documentclass[12pt]{minimal}\begin{document}$\mathcal {L}_{3D}^{su_{3}\times u_{1}}$\end{document}L3Dsu3×u1. Other features such as reduction to twisted 2D supersymmetry with 8 supercharges living on \documentclass[12pt]{minimal}\begin{document}$\mathbb {L}_{2D}\equiv \mathcal {L}_{2D}^{su_{2}\times u_{1}}$\end{document}L2D≡L2Dsu2×u1, the extension to twisted maximal 5D SYM with 16 supercharges on lattice \documentclass[12pt]{minimal}\begin{document}$\mathbb {L}_{5D}\equiv \mathcal {L}_{5D}^{su_{4}\times u_{1}}$\end{document}L5D≡L5Dsu4×u1 as well as the relation with known results are also given.
Stationary solid particle attractors in standing waves
Authors: Lappa Marcello
Published: January 2014

The present analysis extends earlier theories on patterns formed by the spontaneous accumulation and ordering of solid particles in certain types of flow by considering the case in which the particle carrier flow has the typical features of a “standing wave.” For the first time an explanation for this phenomenon is elaborated through arguments based on the interplay between vorticity and wave-interference dynamics (following a deductive approach after the so-called phase-locking or “resonance” model originally introduced by Pushkin et al. [Phys. Rev. Lett. 106, 234501 (2011)] and later variants developed by Lappa [Phys. Fluids 25(1), 012101 (2013) and Lappa, Chaos 23(1), 013105 (2013)]). The results of dedicated numerical simulations are used in synergy with available experimental work. An interesting analogy is proposed with the famous Chladni's series of experiments on patterns formed by sand on vibrating plates.
Enhancement of photoluminescence from defect states in ZnS random photonic crystal: An effect of electronic and photonic mode coupling
Authors: Bingi Jayachandra , Warrier Anita R. , Vijayan C.
Published: January 2014

This paper reports on the enhanced defect state emission from ZnS in the form of a random photonic crystal (RPC) medium. ZnS photonic crystals with varied randomness are fabricated by colloidal self assembly of ZnS nanospheres (215 ± 10 nm). Reflection and transmission studies reveal mid band gap wavelength at ∼435 nm. The band structure calculated for BCC lattice with reduced packing fraction (53%) is in good agreement with experimental results. The reflection due to the photonic band gap diminishes with increased randomness in the nanosphere arrangement. The features of fluorescence from ZnS are modified in the RPC medium, resulting in suppression at wavelengths in the photonic band gap region and an enhancement at band edge wavelengths of 415 and 468 nm. This enhancement becomes less prominent with increasing randomness in the structure. Interestingly these two modes correspond to the electronic defect states of ZnS. Emission enhancement is shown to be due to the strong coupling of electronic defect states and photonic band edge states which is facilitated by randomly scattering slow Bloch modes in the ZnS RPC. Fabrication of RPCs by colloidal self-assembly with specifically designed degrees of randomness (leading to controllable features of emission) provides scope for the design of low threshold random lasing systems.
Faster motion of double 360° domain walls system induced by spin-polarized current
Authors: Zhang S. F. , Zhu Q. Y. , Mu C. P. , Zheng Q. , Liu X. Y. , Liu Q. F. , Wang J. B.
Published: January 2014

By micromagnetic simulation, we investigated a double 360° domain walls system in two parallel nanowires. Two domain walls are coupled to each other via magnetostatic interaction. When a spin-polarized current is applied to only one nanowire or both nanowires with the same direction, the two domain walls propagate along nanowires together. The critical velocity of such system is obviously higher than that of a single 360° domain wall. The interaction between the two domain walls can be modeled as two bodies that connected by a spring, and we analyzed the coupling characteritics of the double 360° domain walls at last.
Simulation of cross-talk between thermal track positioning control and thermal flying height control
Authors: Li Hui , Shen Shengnan , Cui Fuhao , Huang Jie , Wu Shijing
Published: January 2014

In this study, a coupling analysis of thermal-structural simulation and air-bearing simulation has been performed to investigate the cross-talk effects between thermal track positioning control (TPC) and thermal flying height control (TFC) on the static flying attitude of a TPC-TFC slider. Simulation results show that the TPC heating induced head protrusion towards disk is comparable to the head actuation stroke along the cross-track direction. By optimizing the distance of TPC heater to air bearing surface, and the distance of TPC heater to the slider center line, it can obtain a large TPC actuation stroke and a small head protrusion towards disk. Moreover, it is found that the TPC heating will cause large protrusion of the side edge of trailing pad and change the flying characteristics significantly. A trade-off performance between cross-talk effects and TPC actuation stroke along cross-track direction is needed.
Quality-enhanced In0.3Ga0.7As film grown on GaAs substrate with an ultrathin amorphous In0.6Ga0.4As buffer layer
Authors: Gao Fangliang , Li Guoqiang
Published: January 2014

Using low-temperature molecular beam epitaxy, amorphous In0.6Ga0.4As layers have been grown on GaAs substrates to act as buffer layers for the subsequent epitaxial growth of In0.3Ga0.7As films. It is revealed that the crystallinity of as-grown In0.3Ga0.7As films is strongly affected by the thickness of the large-mismatched amorphous In0.6Ga0.4As buffer layer. Given an optimized thickness of 2 nm, this amorphous In0.6Ga0.4As buffer layer can efficiently release the misfit strain between the In0.3Ga0.7As epi-layer and the GaAs substrate, trap the threading and misfit dislocations from propagating to the following In0.3Ga0.7As epi-layer, and reduce the surface fluctuation of the as-grown In0.3Ga0.7As, leading to a high-quality In0.3Ga0.7As film with competitive crystallinity to that grown on GaAs substrate using compositionally graded InxGa1-xAs metamorphic buffer layers. Considering the complexity of the application of the conventional InxGa1-xAs graded buffer layers, this work demonstrates a much simpler approach to achieve high-quality In0.3Ga0.7As film on GaAs substrate and, therefore, is of huge potential for the InGaAs-based high-efficiency photovoltaic industry.
Bichromatic random laser from a powder of rhodamine-doped sub-micrometer silica particles
Authors: Barbosa-Silva Renato , Silva Andrea F. , Brito-Silva Antonio M. , de Araújo Cid B.
Published: January 2014

We studied the random laser (RL) bichromatic emission (BCE) from a powder consisting of silica particles infiltrated with Rhodamine 640 (Rh640) molecules. The BCE is attributed to Rh640 monomers and dimers. Because of the efficient monomer-dimer energy transfer, we observed RL wavelength switching from ≈ 620 nm to ≈650 nm and the control of the emitted wavelength was made by changing only the excitation laser intensity. None of external parameters such as excitation laser spot size or radiation detector position was changed as in previous experiments. Two laser thresholds associated either to monomers or dimers were clearly observed. Moreover, an effect analog to frequency-pulling among two coupled oscillators was identified measuring the RL spectra as a function of the excitation laser intensity. A wavelength shift, Δλ, was measured between the monomer and dimer resonance wavelengths, changing only the excitation laser intensity. The maximum value of Δλ ≈ 16 cm−1 was obtained for laser pulses of 7 ns with 30 μJ.
Coexistence of superconductivity and commensurate charge density wave in 4Hb-TaS2−xSex single crystals
Authors: Liu Y. , Li L. J. , Lu W. J. , Ang R. , Liu X. Z. , Sun Y. P.
Published: January 2014

The transition-metal dichalcogenides, a family of graphene-like two-dimensional (2D) materials, exhibit exciting properties for potential applications and fundamental researches. We successfully fabricated a new series of 4Hb-TaS2−xSex (0 ≤ x ≤ 1.5) single crystals by chemical vapor transport technique. This is the first time to demonstrate the coexistence of superconductivity and commensurate charge density wave (CCDW) in 4Hb-TaS2−xSex (0 ≤ x ≤ 1.5). The evolution of the electronic states tuned by Se-doping are also exhibited in the phase diagram. Taking into account the special crystal structure of 4Hb-TaS2−xSex (0 ≤ x ≤ 1.5), we draw a conclusion that the H- and T-layers play a crucial role to dominate the state of superconductivity and CCDW, respectively.
Fabrication of p-type ZnO nanofibers by electrospinning for field-effect and rectifying devices
Authors: Liu Shuai , Liu Shu-Liang , Long Yun-Ze , Liu Ling-Zhi , Zhang Hong-Di , Zhang Jun-Cheng , Han Wen-Peng , Liu Yi-Chen
Published: January 2014

Ce-doped p-type ZnO nanofibers were synthesized by electrospinning and followed calcinations. The surface morphology, elementary composition, and crystal structure of the nanofibers were investigated. The field effect curve confirms that the resultant Ce-doped ZnO nanofibers are p-type semiconductor. A p-n heterojunction device consisting of Ce-doped p-type ZnO nanofibers and n-type indium tin oxide (ITO) thin film was fabricated on a piece of quartz substrate. The current-voltage (I-V) characteristic of the p-n heterojunction device shows typical rectifying diode behavior. The turn-on voltage appears at about 7 V under the forward bias and the reverse current is impassable.
Fabrication of carbon nanotube emitters on the graphite rod and their high field emission performance
Authors: Sun Yuning , Song Yenan , Hoon Shin Dong , Nam Yun Ki , Jeon Seok-Gy , Kim Jung-Il , Saito Yahachi , Jin Lee Cheol
Published: January 2014

Carbon nanotube (CNT) emitters with small emission area were fabricated on graphite rods using CNT films. By introducing the edge polishing process, the field emission performance of the CNT emitter was much improved, which showed a very high emission current of 6.34 mA (1.6 A/cm2) under an applied electric field of 5.3 V/μm. It also indicates good long-term emission stability, which reveals no degradation in the emission current for 20 h. The emission patterns demonstrate uniform and well-focused electron beam spots. The enhanced field emission performance is mainly attributed to the suppressed edge emission after the edge polishing process.
Empirical evidence for identical band gaps in substituted C60 and C70 based fullerenes
Authors: Mattias Andersson L. , Tanaka Hideyuki
Published: January 2014

Optical absorptance data, and a strong correlation between solar cell open circuit voltages and the ionization potentials of a wide range of differently substituted fullerene acceptors, are presented as empirical evidence for identical, or at least very similar, band gaps in all substituted C60 and C70 based fullerenes. Both the number and kind of substituents in this study are sufficiently varied to imply generality. While the band gaps of the fullerenes remain the same for all the different substitutions, their ionization potentials vary greatly in a span of more than 0.4 eV. The merits and drawbacks of using these results together with photoelectron based techniques to determine relative fullerene energy levels for, e.g., organic solar cell applications compared to more direct electrochemical methods are also discussed.
A numerical simulation study of gallium-phosphide/silicon heterojunction passivated emitter and rear solar cells
Authors: Wagner Hannes , Ohrdes Tobias , Dastgheib-Shirazi Amir , Puthen-Veettil Binesh , König Dirk , Altermatt Pietro P.
Published: January 2014

The performance of passivated emitter and rear (PERC) solar cells made of p-type Si wafers is often limited by recombination in the phosphorus-doped emitter. To overcome this limitation, a realistic PERC solar cell is simulated, whereby the conventional phosphorus-doped emitter is replaced by a thin, crystalline gallium phosphide (GaP) layer. The resulting GaP/Si PERC cell is compared to Si PERC cells, which have (i) a standard POCl3 diffused emitter, (ii) a solid-state diffused emitter, or (iii) a high efficiency ion-implanted emitter. The maximum efficiencies for these realistic PERC cells are between 20.5% and 21.2% for the phosphorus-doped emitters (i)–(iii), and up to 21.6% for the GaP emitter. The major advantage of this GaP hetero-emitter is a significantly reduced recombination loss, resulting in a higher Voc. This is so because the high valence band offset between GaP and Si acts as a nearly ideal minority carrier blocker. This effect is comparable to amorphous Si. However, the GaP layer can be contacted with metal fingers like crystalline Si, so no conductive oxide is necessary. Compared to the conventional PERC structure, the GaP/Si PERC cell requires a lower Si base doping density, which reduces the impact of the boron-oxygen complexes. Despite the lower base doping, fewer rear local contacts are necessary. This is so because the GaP emitter shows reduced recombination, leading to a higher minority electron density in the base and, in turn, to a higher base conductivity.
Impact of light on leaf initiation: a matter of photosynthate availability in the apical bud?
Authors: Savvides Andreas , Ntagkas Nikolaos , van Ieperen Wim , Dieleman Janneke A. , Marcelis Leo F. M.
Published: January 2014

Radiation substantially affects leaf initiation rate (LIR), a key variable for plant growth, by influencing the heat budget and therefore the temperature of the shoot apical meristem. The photosynthetically active component of solar radiation (photosynthetic photon flux density; PPFD) is critical for plant growth and when at shade to moderate levels may also influence LIR via limited photosynthate availability. Cucumber and tomato plants were subjected to different PPFDs (2.5–13.2 mol m–2 day–1) and then LIR, carbohydrate content and diel net CO2 uptake of the apical bud were quantified. LIR showed saturating response to increasing PPFD in both species. In this PPFD range, LIR was reduced by 20% in cucumber and by 40% in tomato plants. Carbohydrate content and dark respiration were substantially reduced at low PPFD. LIR may be considered as an adaptive trait of plants to low light levels, which is likely to be determined by the local photosynthate availability. In tomato and cucumber plants, LIR can be markedly reduced at low PPFD in plant production systems at high latitudes, suggesting that models solely based on thermal time may not precisely predict LIR at low PPFD.
Stomatal pore size and density in mangrove leaves and artificial leaves: effects on leaf water isotopic enrichment during transpiration
Authors: Sternberg Leonel da Silveira Lobo , Manganiello Lynn M.
Published: January 2014

We tested the hypothesis that the previously observed low isotopic enrichment of mangrove leaf water is caused by larger stomatal pores and lower densities compared with freshwater plants. First, we measured and compared pore size and density in mangroves, transitional and freshwater species in South Florida. We pooled this data with other reports encompassing 14 mangrove species and 134 freshwater species and tested for differences in pore size and density between mangroves and freshwater plants. Second, we built artificial leaves having different pore size and density and determined whether there were isotopic differences in their water after transpiration. Both the local survey and pooled data showed that mangrove leaves have significantly larger stomatal pores with lower densities compared with freshwater plants. Isotope enrichment of water from artificial leaves having larger less dense pores was lower than those having smaller and denser pores. Stomatal pore size and density has an effect on leaf water isotopic enrichment amongst other factors. Pore size and density probably affects key components of the Peclet ratio such as the distance advective flow of water must travel to the evaporative surface and the cross-sectional area of advective flow. These components, in turn, affect leaf water isotopic enrichment. Results from the artificial leaf experiment also mimic a recent finding that effective path length scales to the inverse of transpiration in real leaves. The implications of these findings further our understanding of leaf water isotope ratios and are important in applications of stable isotopes in the study of paleoclimate and atmospheric processes.
Over-expression of SlCycA3 gene in Arabidopsis accelerated the cell cycle transition
Authors: Guo Jia , Wu Jiawen , Zhang Tiantian , Gong Haijun
Published: January 2014

We characterised an A-type cyclin SlCycA3 (AJ243453) from tomato (Solanum lycopersicum L.). Phylogenetic analysis based on the deduced amino acid sequence revealed that SlCycA3 was 71% identical to A3-type cyclin in Nicotiana tabacum L. (CAA63540), 48% identical to its homologue found in Arabidopsis thaliana (NP_199122), and 48% identical to its homologue in Pisum sativum L. (CAB77269). SlCycA3 gene was transformed into Arabidopsis plants in order to study its function. The hypocotyl length of transgenic plants was approximately half the length of wild-type plants, and the cell size in the transgenic lines was also smaller. The transgenic plants had longer roots than the wild type. Overexpression of SlCycA3 gene accelerated the cell cycle from G1/S transition to early M-phase, thereby accelerating the cell division. When the plants were treated with IAA and 3-indolebutyric acid (IBA) for 2 days, the transgenic plants produced more lateral roots than wild type. Treatment with IBA significantly increased the cell number in the G2-phase in transgenic plants compared with wild type after treatment for 10 days, whereas the proportion of cells in the S-phase was strongly increased by IAA treatment both in wild-type and transgenic plants. These results suggest a possible key role for cyclin in regulating root growth and development and provide some evidence of cell division underlying hormone treatment in plants.
Maximum age and missing time in the vertebrae of sand tiger shark (Carcharias taurus): validated lifespan from bomb radiocarbon dating in the western North Atlantic and southwestern Indian Oceans
Authors: Passerotti M. S. , Andrews A. H. , Carlson J. K. , Wintner S. P. , Goldman K. J. , Natanson L. J.
Published: January 2014

Bomb radiocarbon analysis of vertebral growth bands was used to validate lifespan for sand tiger sharks (Carcharias taurus) from the western North Atlantic (WNA) and southwestern Indian Oceans (SIO). Visual counts of vertebral growth bands were used to assign age and estimate year of formation (YOF) for sampled growth bands in eight sharks from the WNA and two sharks from the SIO. Carbon-14 results were plotted relative to YOF for comparison with regional Δ14C reference chronologies to assess the accuracy of age estimates. Results from the WNA validated vertebral age estimates up to 12 years, but indicated that ages of large adult sharks were underestimated by 11–12 years. Age was also underestimated for adult sharks from the SIO by 14–18 years. Validated lifespan for C. taurus individuals in the present study reached at least 40 years for females and 34 years for males. Findings indicated that the current age-reading methodology is not suitable for estimating the age of C. taurus beyond ~12 years. Future work should investigate whether vertebrae of C. taurus record age throughout ontogeny, or cease to be a reliable indicator at some point in time.
A quantitative metric differentiation theorem
Authors: Azzam Jonas , Schul Raanan
Published: January 2014

The purpose of this note is to point out a simple consequence of some earlier work of the authors, “Hard Sard: Quantitative implicit function and extension theorems for Lipschitz maps”. For

f
f

, a Lipschitz function from a Euclidean space into a metric space, we give quantitative estimates for how often the pullback of the metric under

f
f

is approximately a seminorm. This is a quantitative version of Kirchheim’s metric differentiation result from 1994. Our result is in the form of a Carleson packing condition.
Limit theorems for rank-one Lie groups
Authors: Gorodnik Alexander , Ramírez Felipe
Published: January 2014

We investigate asymptotic behaviour of averaging operators for actions of simple rank-one Lie groups. It was previously known that these averaging operators converge almost everywhere, and we establish a more precise asymptotic formula that describes their deviations from the limit.
Bridgeland stability conditions on threefolds II: An application to Fujita’s conjecture
Authors: Bayer Arend , Bertram Aaron , Macrì Emanuele , Toda Yukinobu
Published: January 2014

We apply a conjectured inequality on third Chern classes of stable two-term complexes on threefolds to Fujita’s conjecture. More precisely, the inequality is shown to imply a Reider-type theorem in dimension three which in turn implies that

K
X

+
6
L

K_X + 6L

is very ample when

L
L

is ample, and that

5
L

5L

is very ample when

K
X

K_X

is trivial.
S/MAR sequence confers long-term mitotic stability on non-integrating lentiviral vector episomes without selection
Authors: Verghese Santhosh Chakkaramakkil , Goloviznina Natalya A. , Skinner Amy M. , Lipps Hans J. , Kurre Peter
Published: January 2014

Insertional oncogene activation and aberrant splicing have proved to be major setbacks for retroviral stem cell gene therapy. Integrase-deficient human immunodeficiency virus-1-derived vectors provide a potentially safer approach, but their circular genomes are rapidly lost during cell division. Here we describe a novel lentiviral vector (LV) that incorporates human ß-interferon scaffold/matrix-associated region sequences to provide an origin of replication for long-term mitotic maintenance of the episomal LTR circles. The resulting ‘anchoring’ non-integrating lentiviral vector (aniLV) achieved initial transduction rates comparable with integrating vector followed by progressive establishment of long-term episomal expression in a subset of cells. Analysis of aniLV-transduced single cell-derived clones maintained without selective pressure for >100 rounds of cell division showed sustained transgene expression from episomes and provided molecular evidence for long-term episome maintenance. To evaluate aniLV performance in primary cells, we transduced lineage-depleted murine hematopoietic progenitor cells, observing GFP expression in clonogenic progenitor colonies and peripheral blood leukocyte chimerism following transplantation into conditioned hosts. In aggregate, our studies suggest that scaffold/matrix-associated region elements can serve as molecular anchors for non-integrating lentivector episomes, providing sustained gene expression through successive rounds of cell division and progenitor differentiation in vitro and in vivo.
Investigating the Host Range of the US-22, US-23, and US-24 Clonal Lineages of Phytophthora infestans on Solanaceous Cultivated Plants and Weeds
Authors: Seidl Johnson Anna C. , Gevens Amanda J.
Published: January 2014

Phytophthora infestans causes late blight, one of the most important diseases of potato and tomato worldwide. Recently in the United States, three newly identified clonal lineages, US-22, US-23, and US-24, have become widespread. While potato and tomato are the most commonly infected solanaceous hosts for P. infestans, new lineages may have a broader or different host range. Under controlled conditions, we determined the host range of isolates representing US-22, US-23, and US-24 genotypes of P. infestans on detached tissues of cultivated solanaceous plants and solanaceous weeds common to the upper midwestern production region. None of the isolates representing the clonal lineages produced late blight symptoms or signs on foliage of selected cultivars of eggplant, pepper, tomatillo, or ground cherry in a detached leaf assay. Symptoms and signs were evident on the potato and tomato cultivars tested, although with the US-24 isolate, infection on tomato was limited. None of the isolates sporulated on the common weed black nightshade, but some sporulation and necrosis was observed with all representatives of the lineages on bittersweet nightshade and petunia. Hairy nightshade supported abundant sporulation and symptoms, and sporangial production was not significantly different than that on tomato for each of the isolates representing the three lineages, indicating the potential for this weed to be a source of inoculum and contribute substantially to late blight epidemics. Interestingly, black nightshade had the highest incidence of sporulation on berries, but the lowest on leaves, suggesting the importance of testing multiple plant organs when determining susceptibility of a species. Our results update knowledge of the host range of the ever-changing P. infestans populations and will help to improve late blight management strategies by targeting these additional hosts.
Incidence and Severity of Cavity Spot of Carrot as Affected by Pigmentation, Temperature, and Rainfall
Authors: Saude C. , Simon P. W. , McDonald M. R.
Published: January 2014

Field trials to determine the effect of carrot pigmentation and weather parameters on cavity spot (CS) of carrot were conducted in the Holland/ Bradford Marsh region of Ontario between 2002 and 2009. In all, 23 colored carrot cultivars from the United States Department of Agriculture (USDA) Agricultural Research Service breeding program at the University of Wisconsin (n = 5) and commercial seed companies (n = 18) were seeded in organic soil (pH 6 to 7, 45 to 75% organic matter) in late May to early June and harvested in late October or early November. Carrot roots were assessed for CS severity midseason and postharvest. Evaluations postharvest indicated that the purple pigmented carrot from breeding line ‘USDA 106-3’ and cultivars ‘Purple Rain’ and ‘Purple Haze’ consistently had low CS severity. The orange-pigmented ‘USDA 101-23’, ‘Cellobunch’, ‘YaYa’, and ‘Envy’ had moderate CS; and the red-pigmented carrot breeding line ‘USDA 104-3’ and cultivars ‘Atomic Red’, ‘Proline Red’, ‘Dragon’, and an unnamed line from India had high CS. Differences in CS severity in carrot cultivars between evaluations at midseason and postharvest suggest that some carrot cultivars are more susceptible to Pythium spp. inoculum in soil (alloinfection) and others to secondary infection (autoinfection) that can be attributed to the Pythium sp. involved in CS. CS severity was positively correlated with total rainfall 2 and 3 months after seeding, and was negatively correlated with number of days with air temperature ≥30°C 3 and 4 months after seeding. Soil temperature and total rainfall were the best predictors of CS incidence and severity. These results could allow a forecast of disease incidence and severity at harvest.
First Report of a New Subgroup 16Sr II-M ‘Candidatus Phytoplasma aurantifolia’ Associated with Witches'-Broom Disease of Tephrosia purpurea in India
Authors: Yadav A. , Bhale U. , Thorat V. , Shouche Y.
Published: January 2014

Wild indigo (Tephrosia purpurea (L.) Pers.) grows as a common weed throughout the Indian subcontinent. The plant has pinnate leaves, white or purplish flowers, and flat hairy pods, and is cultivated as a green manure crop. The plant extracts contain compounds such as tephrosin, an aromatic ester, prenylated flavonoid, and sesquiterpene (2) that have medicinal properties. The newly recognized disease, Tephrosia purpurea witches' broom (TPWB), was characterized by chlorosis, stunting, and proliferative branching, which were suggestive of phytoplasma infection during a field survey conducted in November 2013. To determine the presence of phytoplasma, 2 g of compound leaves from three symptomatic and asymptomatic plants were used for total DNA extraction using the CTAB method. The phytoplasma 16S rRNA gene was detected in all three symptomatic plants using nested PCR with universal phytoplasma primer pairs, P1/P7 followed by R16F2n/R16R2 (4). No amplification was observed in DNA isolated from asymptomatic plants. PCR fragments (1,246 bp in length) generated from symptomatic T. purpurea plants were sequenced directly using five different primers viz. 343R, 536F, 704F, 907R, and 1103F. TPWB phytoplasma 16S rRNA gene sequence (GenBank Accession No. HG792252) showed 99.12% homology with a ‘Candidatus Phytoplasma aurantifolia’ strain WBDL (U15442) when compared using the EzTaxon 16S rRNA database (3). Virtual restriction fragment length polymorphism (RFLP) analysis was carried out on the obtained sequence using iPhyClassifier (5). The virtual RFLP pattern derived from the HG792252 sequence was different to the reference patterns of previously established 16Sr groups and subgroups. The reference pattern of the 16Sr group II, subgroup C (AJ293216) was most similar with a similarity coefficient of 0.92, which placed it in a new subgroup, 16Sr II-M (1). Furthermore, virtual RFLP results were confirmed by digesting R16F2n/R16R2 amplicon with BstUI, DraI, HinfI, HpaI, and MseI restriction enzymes according to manufacturer's instructions. To our knowledge, this is the first report of a ‘Ca. P. aurantifolia’-related strain associated with witches'-broom disease of T. purpurea in India.

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