bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of stubble and mulching on soil erosion by wind in semi-arid China
Authors: Cong Peifei , Yin Guanghua , Gu Jian
Published: July 2016

Soil erosion is a growing challenge for agricultural production in Northern China. To explore the effect of variation in stubble height and mulching biomass on soil erosion caused by wind, we conducted a field experiment using a quadratic rotation combination design. Results showed that the quantity of straw mulch was the dominant factor affecting soil erosion and stubble height was of secondary importance. The soil water content in stubble and straw mulching treatments was higher than in a control treatment at 0–20 cm soil and the tendency in the amount of soil water content was opposite to the amount of wind erosion (r = −0.882, n = 10, p < 0.01). The change in soil water content observed in the stubble and mulch treatments at the 15–20 cm depth was higher than the change from 0–5 cm to 5–10 cm. Combined, the influence of a stubble height of 34 cm and mulch quantity of 4260 kg·ha−1 lowered the amount of erosion to 0.42 t·ha−1 and increased the corn yield to 11900 kg·ha−1. We determined that those were the most appropriate levels of stubble height and straw mulch for crop fields in the semi-arid regions of Northern China.
(4R,6S)-2-Dihydromenisdaurilide is a Butenolide that Efficiently Inhibits Hepatitis C Virus Entry
Authors: Chung Chueh-Yao , Liu Ching-Hsuan , Wang Guey-Horng , Jassey Alagie , Li Chia-Lin , Chen Lei , Yen Ming-Hong , Lin Chun-Ching , Lin Liang-Tzung
Published: July 2016

Without a vaccine, hepatitis C virus (HCV) remains a significant threat, putting 170–300 million carriers worldwide at risk of cirrhosis and hepatocellular carcinoma. Although the direct-acting antivirals targeting HCV replication have revolutionized the treatment of hepatitis C, several obstacles persist, including resistance development, potential side-effects and the prohibitive cost that limits their availability. Furthermore, treatment of HCV re-infection in liver transplantation remains a significant challenge. Developing novel antivirals that target viral entry could help expand the scope of HCV therapeutics and treatment strategies. Herein, we report (4R,6S)-2-dihydromenisdaurilide (DHMD), a natural butenolide, as an efficient inhibitor of HCV entry. Specifically, DHMD potently inhibited HCV infection at non-cytotoxic concentration. Examination on the viral life cycle demonstrated that DHMD selectively targeted the early steps of infection while leaving viral replication/translation and assembly/release unaffected. Furthermore, DHMD did not induce an antiviral interferon response. Mechanistic dissection of HCV entry revealed that DHMD could inactivate cell-free virus, abrogate viral attachment and inhibit viral entry/fusion, with the most pronounced effect observed against the viral adsorption phase as validated using ELISA and confocal microscopy. Due to its potency, DHMD may be of value for further development as an entry inhibitor against HCV, particularly for application in transplant setting.
Theory of Multifarious Quantum Phases and Large Anomalous Hall Effect in Pyrochlore Iridate Thin Films
Authors: Hwang Kyusung , Kim Yong Baek
Published: July 2016

We theoretically investigate emergent quantum phases in the thin film geometries of the pyrochore iridates, where a number of exotic quantum ground states are proposed to occur in bulk materials as a result of the interplay between electron correlation and strong spin-orbit coupling. The fate of these bulk phases as well as novel quantum states that may arise only in the thin film platforms, are studied via a theoretical model that allows layer-dependent magnetic structures. It is found that the magnetic order develop in inhomogeneous fashions in the thin film geometries. This leads to a variety of magnetic metal phases with modulated magnetic ordering patterns across different layers. Both the bulk and boundary electronic states in these phases conspire to promote unusual electronic properties. In particular, such phases are akin to the Weyl semimetal phase in the bulk system and they would exhibit an unusually large anomalous Hall effect.
Recurrent HOXB13 mutations in the Dutch population do not associate with increased breast cancer risk
Authors: Liu Jingjing , Prager–van der Smissen Wendy J. C. , Schmidt Marjanka K. , Collée J. Margriet , Cornelissen Sten , Lamping Roy , Nieuwlaat Anja , Foekens John A. , Hooning Maartje J. , Verhoef Senno , van den Ouweland Ans M. W. , Hogervorst Frans B. L. , Martens John W. M. , Hollestelle Antoinette
Published: July 2016

The HOXB13 p.G84E mutation has been firmly established as a prostate cancer susceptibility allele. Although HOXB13 also plays a role in breast tumor progression, the association of HOXB13 p.G84E with breast cancer risk is less evident. Therefore, we comprehensively interrogated the entire HOXB13 coding sequence for mutations in 1,250 non-BRCA1/2 familial breast cancer cases and 800 controls. We identified two predicted deleterious missense mutations, p.G84E and p.R217C, that were recurrent among breast cancer cases and further evaluated their association with breast cancer risk in a larger study. Taken together, 4,520 familial non-BRCA1/2 breast cancer cases and 3,127 controls were genotyped including the cases and controls of the whole gene screen. The concordance rate for the genotyping assays compared with Sanger sequencing was 100%. The prostate cancer risk allele p.G84E was identified in 18 (0.56%) of 3,187 cases and 16 (0.70%) of 2,300 controls (OR = 0.81, 95% CI = 0.41–1.59, P = 0.54). Additionally, p.R217C was identified in 10 (0.31%) of 3,208 cases and 2 (0.087%) of 2,288 controls (OR = 3.57, 95% CI = 0.76–33.57, P = 0.14). These results imply that none of the recurrent HOXB13 mutations in the Dutch population are associated with breast cancer risk, although it may be worthwhile to evaluate p.R217C in a larger study.
Identification and functional analysis of endogenous nitric oxide in a filamentous fungus
Authors: Pengkit Anchalee , Jeon Seong Sil , Son Soo Ji , Shin Jae Ho , Baik Ku Yeon , Choi Eun Ha , Park Gyungsoon
Published: July 2016

In spite of its prevalence in animals and plants, endogenous nitric oxide (NO) has been rarely reported in fungi. We present here our observations on production of intracellular NO and its possible roles during development of Neurospora crassa, a model filamentous fungus. Intracellular NO was detected in hypha 8–16 hours after incubation in Vogel’s minimal liquid media and conidiophores during conidiation using a fluorescent indicator (DAF-FM diacetate). Treatment with cPTIO, an NO scavenger, significantly reduced fluorescence levels and hindered hyphal growth in liquid media and conidiation, whereas exogenous NO enhanced hyphal extension on VM agar media and conidia formation. NO scavenging also dramatically diminished transcription of con-10 and con-13, genes preferentially expressed during conidiation. Our results suggest that intracellular NO is generated in young hypha growing in submerged culture and during conidia development and regulate mycelial development and conidia formation.
Enantioselective rhodium/ruthenium photoredox catalysis en route to chiral 1,2-aminoalcohols
Authors: Ma Jiajia , Harms Klaus , Meggers Eric
Published: July 2016

A visible-light-induced enantioselective redox coupling of α-silylalkylamines with 2-acyl imidazoles is catalyzed by a combination of a chiral Rh Lewis acid and a Ru photoredox sensitizer.
Mechanistic insights into the potassium tert-butoxide-mediated synthesis of N-heterobiaryls
Authors: Stephens David E. , Lakey-Beitia Johant , Burch Jessica E. , Arman Hadi D. , Larionov Oleg V.
Published: July 2016

N-Heterobiaryls can be prepared directly from heterocyclic N-oxides, or N-heterocycles in a scalable, transition metal-free, KOt-Bu-mediated process.
Manipulating the proton transfer process in molecular complexes: synthesis and spectroscopic studies
Authors: Panja Sumit Kumar , Dwivedi Nidhi , Saha Satyen
Published: July 2016

The proton transfer process in carefully designed molecular complexes has been investigated directly in the solid and solution phase.
Coupling electrophoretic separation with inductively coupled plasma spectroscopic detection: interfaces and applications from elemental speciation, metal–ligand interaction to indirect determination
Authors: Cheng Heyong , Li Pu , Liu Jinhua , Ye Meiying
Published: July 2016

Electrophoresis in capillaries/microchannels interfaced with inductively coupled plasma spectrometries shows great potential in elemental speciation and interaction with ligands, and indirect determination by taking advantage of both separation and detection.
Customisable 3D printed microfluidics for integrated analysis and optimisation
Authors: Monaghan T. , Harding M. J. , Harris R. A. , Friel R. J. , Christie S. D. R.
Published: July 2016

3DP was used to produce a fluidic device with embedded optical fibres capable of performing UV-vis spectroscopy directly inside micro-channels.
The role of boronic acids in accelerating condensation reactions of α-effect amines with carbonyls
Authors: Gillingham Dennis
Published: July 2016

A broad palette of bioconjugation reactions are available for chemical biologists, but an area that still requires investigation is high-rate constant reactions. Here I examine recent studies describing boronic acid accelerated oxime condensations, with a particular emphasis on reports from my group.
Efficient construction of the A/C/D tricyclic skeleton of palhinine A
Authors: Duan Shuangshuang , Long Dan , Zhao Changgui , Zhao Gaoyuan , Yuan Ziyun , Xie Xingang , Fang Jianguo , She Xuegong
Published: July 2016

An efficient approach for the synthesis of the 9/6/6 tricyclic structure ofLycopodiumalkaloid palhinine A has been accomplished. This protocol can undergo ring constriction to rapidly construct the highly strained nine-membered azonane ring of palhinine A.
Crosslinked polymeric self-assemblies as an efficient strategy for photodynamic therapy on a 3D cell culture
Authors: Till Ugo , Gibot Laure , Vicendo Patricia , Rols Marie-Pierre , Gaucher Mireille , Violleau Frédéric , Mingotaud Anne-Françoise
Published: July 2016

Polymeric crosslinked self-assemblies based on poly(ethyleneoxide-b-ε-caprolactone) have been synthesized. They are shown to be more efficient vectors for photodynamic therapy compared to uncrosslinked systems.
Sensitive and selective detection of Hg2+based on an electrochemical platform of PDDA functionalized rGO and glutaraldehyde cross-linked chitosan composite film
Authors: Wang Yongxiang , Zhou Lihui , Wang Sen , Li Jinxia , Tang Jing , Wang Shaolei , Wang Ying
Published: July 2016

In this paper, a uniform PDDA-functionalized graphene composite film (GA–CS@PDDA-rGO) was utilized for detection of trace Hg2+by using glutaraldehyde cross-linked chitosan (GA–CS) as a Hg2+-chelating adsorbent and film-forming agent.
Defections induced hydrogenation of silicene: a density functional theory calculation study
Authors: Jiang Q. G. , Wu W. C. , Zhang J. F. , Ao Z. M. , Wu Y. P. , Huang H. J.
Published: July 2016

Vacancy defects significantly depress the energy barrier for dissociative adsorption of H2 on silicene, which can open the band gap of silicene.
Preparing magnetic multicomponent catalysts via a bio-inspired assembly for heterogeneous reactions
Authors: Song Wentong , Tao Shengyang , Yu Yongxian , Du Xuanlu , Wang Shuo
Published: July 2016

A facile synthetic approach for preparing magnetic porous catalysts, from various inorganic compounds loaded by a pyrogallic acid (PG) assisted layer-by-layer (LbL) coating.
Enhancing the efficiency of desensitizing agents with shockwave treatment – a new paradigm in dentinal hypersensitivity management
Authors: Datey Akshay , Adeeb Thaha C. S. , Patil Sudhir R. , Gopalan Jagadeesh , Chakravortty Dipshikha
Published: July 2016

Micro-shockwave assisted dentin hypersensitivity management.
Bis((1,4-dimethyl-9H-carbazol-3-yl)methyl)amine-mediated anticancer effect triggered by sequence-specific cleavage of DNA leading to programmed cell death in the human U87 cell line
Authors: Kumar Nitin , Kumar Rakesh , Nemaysh Vishal , Lal Neetika , Luthra Pratibha Mehta
Published: July 2016

Bis((1,4-dimethyl-9H-carbazol-3-yl)methyl)amine (DMCM) has been designed as a novel anti-cancer agent which is believed to have a sequence-specific groove binding interaction with DNA, leading to anticancer effects.
Scalable preparation of silicon@graphite/carbon microspheres as high-performance lithium-ion battery anode materials
Authors: Wang Hao , Xie Jian , Zhang Shichao , Cao Gaoshao , Zhao Xinbing
Published: July 2016

Silicon materials have received extensive research interest due to their high specific capacity of 3579 mA h g−1and appropriate potential of approximately 0.4 Vvs.Li/Li+.
Hollow Li1.2Mn0.54Ni0.13Co0.13O2 micro-spheres synthesized by a co-precipitation method as a high-performance cathode material for Li-ion batteries
Authors: Li Yanxiu , Mei Jun , Guo Xiaodong , Zhong Benhe , Liu Hao , Liu Guobiao , Dou Shixue
Published: July 2016

Hollow Li1.2Mn0.54Ni0.13Co0.13O2 micro-spheres were successfully synthesized by a co-precipitation method.
A facile low temperature route to deposit a TiO2 scattering layer for efficient dye-sensitized solar cells
Authors: Garmaroudi Zahra Andaji , Abdi-Jalebi Mojtaba , Mohammadi Mohammad Reza , Friend Richard H.
Published: July 2016

Hydrolysis of TiCl4 at low temperature formed an efficient scattering layer in dye-sensitized solar cell architecture, which leads to an improvement in the light harvesting and a remarkable reduction of electronic disorder of mesoporous-TiO2.
Ruthenium-catalyzed 1,2,3-triazole directed intermolecular C–H amidation of arenes with sulfonyl azides
Authors: Wang Xiaoyu , Zhang Chen , Li Jue , Jiang Chong , Su Fu , Zhan Zhen , Hai Li , Chen Zhonghua , Wu Yong
Published: July 2016

An efficient strategy for the synthesis of 2-(2H-1,2,3-triazole-2-yl)aniline derivatives from 2-aryl-1,2,3-triazoles and sulfonylazides through ruthenium-catalyzed intermolecular C–H amidation is achieved.
Bisthienylethenes containing an imidazole bridge unit and their Ir(iii) complexes: influence of substituent groups on photochromism and luminescence
Authors: Gong Dan-Ping , Gao Tai-Bao , Cao Deng-Ke , Ward Michael D.
Published: July 2016

This work reports the syntheses of tBuLH and tBuLMeH, and their complexes [Ir(dfppy)2(tBuL)]·2CH3OH (1) and Ir(dfppy)2(tBuLMe)] (2), and the influence of substituent groups –C(CH3)3 and –CH3 on their photochromic and luminescence behaviors.
Mixed ionic-electronic conductivity and thermochemical expansion of Ca and Mo co-substituted pyrochlore-type Gd2Ti2O7
Authors: Zakharchuk Kiryl , Kravchenko Ekaterina , Fagg Duncan P. , Frade Jorge R. , Yaremchenko Aleksey A.
Published: July 2016

Co-substitutions with calcium and molybdenum in pyrochlore-type (Gd1−xCax)2(Ti1−yMoy)2O7−δ induce mixed ionic-electronic conductivity under reducing conditions characteristic for solid oxide fuel cell anode operation.
Electronic properties of a pristine and NH3/NO2 adsorbed buckled arsenene monolayer
Authors: Khan Md. Shahzad , Srivastava Anurag , Pandey Ravindra
Published: July 2016

The electronic charge density associated with the inter-frontier orbitals of (a) NH3 arsenene and (b) NO2-arsenene.
The detrimental effect of excess mobile ions in planar CH3NH3PbI3 perovskite solar cells
Authors: Cheng Yuanhang , Li Ho-Wa , Qing Jian , Yang Qing-Dan , Guan Zhiqiang , Liu Chen , Cheung Sin Hang , So Shu Kong , Lee Chun-Sing , Tsang Sai-Wing
Published: July 2016

Mobile ions not only have detrimental effects on device performance but also trigger the degradation of perovskite during device operation.
Nanomaterial-based vaccine adjuvants
Authors: Sun Bingbing , Xia Tian
Published: July 2016

Engineered nanomaterials as vaccine adjuvants are capable of potentiating the immune responses through different mechanisms.
Fabrication of hybridized nanoparticles with aggregation-induced emission characteristics and application for cell imaging
Authors: Wang Zhengke , Liu Yalan , Jia Jingwei , Chen Sijie , Qin Wei , Hu Qiaoling , Tang Ben Zhong
Published: July 2016

More TPE-CS/HA nanoparticles are endocytosed by culture for a long time, resulting in a much stronger fluorescence emission.
Performance modulation of transparent ALD indium oxide films on flexible substrates: transition between metal-like conductor and high performance semiconductor states
Authors: Sheng Jiazhen , Choi Dong-won , Lee Seung-Hwan , Park Jozeph , Park Jin-Seong
Published: July 2016

Atomic layer deposited indium oxide films with the hydrogen peroxide reactant exhibited performance modulation between a semiconductor and a conductor on a flexible substrate.
Tunable hierarchical Fe nanowires with a facile template-free approach for enhanced microwave absorption performance
Authors: Shen Junyao , Yao Yongtao , Liu Yanju , Leng Jinsong
Published: July 2016

A facile, template-free route for Fe nanowires with an average diameter of 100 nm has been introduced through magnetic-field-assisted hydrothermal conditions.
Correntropy induced joint power and admission control algorithm for dense small cell network
Authors: Luan Zhirong , Qu Hua , Zhao Jihong , Chen Badong , Principe Jose C.
Published: July 2016

The authors consider the joint admission and power control problem in a dense small cell network, which contains multiple interference links. The goal is to mainly maximise the number of the admitted links, and at the same time minimise the transmit power. The authors formulate the admission control and power control problem as a joint optimisation problem, which is however non‐deterministic polynomial hard (NP‐hard). Such NP‐hard problem can be relaxed to a p‐norm problem (0 < p < 1) by using the correntropy induced metric. The correntropy is a novel non‐linear similarity measure, which has been successfully used in the robust and spares signal processing, especially when the data contain large outliers. Thus, in this work the authors propose a new correntropy induced joint power and admission control algorithm. To achieve a faster convergence speed, the authors also propose an adaptive kernel size method, in which the kernel size is determined by the error so that the convergence speed is the fastest during the iterations. Simulation results show that the proposed approach can achieve much better results than the existing works.
Das praktische Vorgehen beim postoperativen und posttraumatischen Lymphödem
Authors: Hirsch T. , Wahl U.
Published: July 2016

Schwellungen der Extremitäten sind nach traumatischen Läsionen häufig zu beobachten und stellen eine differenzialdiagnostische Herausforderung dar. Als Ursache sind neben Seromen bzw. Hämatomen und Thrombosen nicht selten auch lymphostatische Ödeme zu identifizieren, welche unbehandelt einen chronischen Verlauf nehmen. Sie sind charakterisiert durch einen hohen Eiweißanteil und führen langfristig durch fibrotischen Gewebeumbau zu erheblichen Behinderungen und Komplikationen wie rezidivierende Erysipele. Die Diagnosestellung erfolgt i. d. R. klinisch, was die Kenntnis der Symptomatik voraussetzt. Die wichtigste Behandlungsoption stellt die Komplexe Physikalische Entstauung dar. Hierbei kommen manuelle Lymphdrainage und lymphologische Mehrkomponentenverbände in mindestens täglicher Frequenz zur Anwendung. Nur in Einzelfällen sind auch chirurgische Interventionen möglich. Aufgrund ihres chronischen Verlaufs mit möglicher Invalidisierung sind posttraumatische Lymphödeme nicht selten Gegenstand der Begutachtung im Rahmen von Verfahren der gesetzlichen und privaten Unfallversicherung. Die vorliegende Arbeit erläutert die Entstehungsmechanismen posttraumatischer Lymphödeme und bietet eine Übersicht zu differenzialdiagnostischen Methoden und den aktuellen therapeutischen Empfehlungen. Zudem gehen die Autoren auf versicherungsrelevante Aspekte ein.
Temperature and composition-dependent density of states in organic small-molecule/polymer blend transistors
Authors: Hunter Simon , Mottram Alexander D. , Anthopoulos Thomas D.
Published: July 2016

The density of trap states (DOS) in organic p-type transistors based on the small-molecule 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (diF-TES ADT), the polymer poly(triarylamine) and blends thereof are investigated. The DOS in these devices are measured as a function of semiconductor composition and operating temperature. We show that increasing operating temperature causes a broadening of the DOS below 250 K. Characteristic trap depths of ∼15 meV are measured at 100 K, increasing to between 20 and 50 meV at room-temperature, dependent on the semiconductor composition. Semiconductor films with high concentrations of diF-TES ADT exhibit both a greater density of trap states as well as broader DOS distributions when measured at room-temperature. These results shed light on the underlying charge transport mechanisms in organic blend semiconductors and the apparent freezing-out of hole conduction through the polymer and mixed polymer/small molecule phases at temperatures below 225 K.
Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible 3He/10 T cryostat
Authors: von Allwörden H. , Ruschmeier K. , Köhler A. , Eelbo T. , Schwarz A. , Wiesendanger R.
Published: July 2016

The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped 3He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where the tip and sample can be exchanged in situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).
The effect of non-extensive particles on slowing down and diffusion of a particle's beam in the plasma
Authors: Ebne Abbasi Z. , Esfandyari-Kalejahi A.
Published: July 2016

The slowing down as well as the deflection time of test particles in the plasma is studied in the non-extensive statistics. The relevant relations are derived using Fokker Planck equation. It is remarked that the slowing down and deflection times modify considerably in the non-extensive statistics in comparison with Boltzmann Gibbs one. It is found that by decreasing non-extensivity index q (1/3<q≤1 which corresponds to plasma with excess super extensive particles), both the slowing down and deflection times will be increased. Also, for q≥1, i.e., the sub-extensive particles, the same results are obtained by decreasing q. Additionally, the effects of non-extensive distributed particles on the electrical conductivity and diffusion coefficient of plasma are studied. It is shown that plasmas with smaller qs are better conductors in both 1/3<q≤1 and q≥1. In addition, it is observed that by increasing q, Dreicer field will increase in both super-extensive and sub-extensive particles. Moreover, it is found that the diffusion coefficient across a magnetic field is decreased by decreasing q. Furthermore, our results reduce to the solutions of Maxwellian plasma at the extensive limit q → 1. This research will be helpful in understanding the relaxation times and transport properties of fusion and astrophysical plasmas.
Automated property optimization via ab initio O(N) elongation method: Application to (hyper-)polarizability in DNA
Authors: Orimoto Yuuichi , Aoki Yuriko
Published: July 2016

An automated property optimization method was developed based on the ab initio O(N) elongation (ELG) method and applied to the optimization of nonlinear optical (NLO) properties in DNA as a first test. The ELG method mimics a polymerization reaction on a computer, and the reaction terminal of a starting cluster is attacked by monomers sequentially to elongate the electronic structure of the system by solving in each step a limited space including the terminal (localized molecular orbitals at the terminal) and monomer. The ELG-finite field (ELG-FF) method for calculating (hyper-)polarizabilities was used as the engine program of the optimization method, and it was found to show linear scaling efficiency while maintaining high computational accuracy for a random sequenced DNA model. Furthermore, the self-consistent field convergence was significantly improved by using the ELG-FF method compared with a conventional method, and it can lead to more feasible NLO property values in the FF treatment. The automated optimization method successfully chose an appropriate base pair from four base pairs (A, T, G, and C) for each elongation step according to an evaluation function. From test optimizations for the first order hyper-polarizability (β) in DNA, a substantial difference was observed depending on optimization conditions between “choose-maximum” (choose a base pair giving the maximum β for each step) and “choose-minimum” (choose a base pair giving the minimum β). In contrast, there was an ambiguous difference between these conditions for optimizing the second order hyper-polarizability (γ) because of the small absolute value of γ and the limitation of numerical differential calculations in the FF method. It can be concluded that the ab initio level property optimization method introduced here can be an effective step towards an advanced computer aided material design method as long as the numerical limitation of the FF method is taken into account.
A versatile rotary-stage high frequency probe station for studying magnetic films and devices
Authors: He Shikun , Meng Zhaoliang , Huang Lisen , Yap Lee Koon , Zhou Tiejun , Panagopoulos Christos
Published: July 2016

We present a rotary-stage microwave probe station suitable for magnetic films and spintronic devices. Two stages, one for field rotation from parallel to perpendicular to the sample plane (out-of-plane) and the other intended for field rotation within the sample plane (in-plane) have been designed. The sample probes and micro-positioners are rotated simultaneously with the stages, which allows the field orientation to cover θ from 0∘ to 90∘ and φ from 0∘ to 360∘. θ and φ being the angle between the direction of current flow and field in a out-of-plane and an in-plane rotation, respectively. The operation frequency is up to 40 GHz and the magnetic field up to 1 T. The sample holder vision system and probe assembly are compactly designed for the probes to land on a wafer with diameter up to 3 cm. Using homemade multi-pin probes and commercially available high frequency probes, several applications including 4-probe DC measurements, the determination of domain wall velocity, and spin transfer torque ferromagnetic resonance are demonstrated.
Using band engineering to tailor the emission spectra of trichromatic semipolar InGaN light-emitting diodes for phosphor-free polarized white light emission
Authors: Kowsz S. J. , Pynn C. D. , Oh S. H. , Farrell R. M. , DenBaars S. P. , Nakamura S.
Published: July 2016

We report a polarized white light-emitting device that monolithically integrates an electrically injected blue light-emitting diode grown on the (202¯1¯) face of a bulk GaN substrate and optically pumped InGaN quantum wells (QWs) with green and red light emission grown on the (202¯1) face. To overcome the challenges associated with growing high indium content InGaN QWs for long wavelength emission, a p-i-n doping profile was used to red-shift the emission wavelength of one of the optically pumped QWs by creating a built-in electric field in the same direction as the polarization-induced electric field. Emission peaks were observed at 450 nm from the electrically injected QW and at 520 nm and 590 nm from the optically pumped QWs, which were situated in n-i-n and p-i-n structures, respectively. The optically pumped QW in the p-i-n structure was grown at a growth temperature that was 10 °C colder compared to the QW in the n-i-n structure, so the emission from the QW in the p-i-n structure was red-shifted due to increased indium content as well as the built-in electric field. Modeling work confirmed that the built-in electric field made a greater contribution than the change in alloy composition to the red-shift in emission from the QW in the p-i-n structure. The combined emission from the red, green, and blue QWs resulted in white-light emission with Commission Internationale de l'Eclairage x- and y-chromaticity coordinates of (0.33, 0.35) and an optical polarization ratio of 0.30.
Analysis of non-equilibrium phenomena in inductively coupled plasma generators
Authors: Zhang W. , Lani A. , Panesi M.
Published: July 2016

This work addresses the modeling of non-equilibrium phenomena in inductively coupled plasma discharges. In the proposed computational model, the electromagnetic induction equation is solved together with the set of Navier-Stokes equations in order to compute the electromagnetic and flow fields, accounting for their mutual interaction. Semi-classical statistical thermodynamics is used to determine the plasma thermodynamic properties, while transport properties are obtained from kinetic principles, with the method of Chapman and Enskog. Particle ambipolar diffusive fluxes are found by solving the Stefan-Maxwell equations with a simple iterative method. Two physico-mathematical formulations are used to model the chemical reaction processes: (1) A Local Thermodynamics Equilibrium (LTE) formulation and (2) a thermo-chemical non-equilibrium (TCNEQ) formulation. In the TCNEQ model, thermal non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules is accounted for. The electronic states of the chemical species are assumed in equilibrium with the vibrational temperature, whereas the rotational energy mode is assumed to be equilibrated with translation. Three different physical models are used to account for the coupling of chemistry and energy transfer processes. Numerical simulations obtained with the LTE and TCNEQ formulations are used to characterize the extent of non-equilibrium of the flow inside the Plasmatron facility at the von Karman Institute. Each model was tested using different kinetic mechanisms to assess the sensitivity of the results to variations in the reaction parameters. A comparison of temperatures and composition profiles at the outlet of the torch demonstrates that the flow is in non-equilibrium for operating conditions characterized by pressures below 30 000 Pa, frequency 0.37 MHz, input power 80 kW, and mass flow 8 g/s.
Communication: Convergence of many-body wave-function expansions using a plane-wave basis in the thermodynamic limit
Authors: Shepherd James J.
Published: July 2016

Basis set incompleteness error and finite size error can manifest concurrently in systems for which the two effects are phenomenologically well-separated in length scale. When this is true, we need not necessarily remove the two sources of error simultaneously. Instead, the errors can be found and remedied in different parts of the basis set. This would be of great benefit to a method such as coupled cluster theory since the combined cost of nocc6nvirt4 could be separated into nocc6 and nvirt4 costs with smaller prefactors. In this Communication, we present analysis on a data set due to Baardsen and co-workers, containing 2D uniform electron gas coupled cluster doubles energies for rs = 0.5, 1.0, and 2.0 a.u. at a wide range of basis set sizes and particle numbers. In obtaining complete basis set limit thermodynamic limit results, we find that within a small and removable error the above assertion is correct for this simple system. We then use this method to obtain similar results for the 3D electron gas at rs = 1.0, 2.0, and 5.0 a.u. and make comparison to the Ceperley–Alder quantum Monte Carlo results. This approach allows for the combination of methods which separately address finite size effects and basis set incompleteness error.
Communication: Two types of flat-planes conditions in density functional theory
Authors: Yang Xiaotian Derrick , Patel Anand H. G. , Miranda-Quintana Ramón Alain , Heidar-Zadeh Farnaz , González-Espinoza Cristina E. , Ayers Paul W.
Published: July 2016

Using results from atomic spectroscopy, we show that there are two types of flat-planes conditions. The first type of flat-planes condition occurs when the energy as a function of the number of electrons of each spin, Nα and Nβ, has a derivative discontinuity on a line segment where the number of electrons, Nα + Nβ, is an integer. The second type of flat-planes condition occurs when the energy has a derivative discontinuity on a line segment where the spin polarization, Nα – Nβ, is an integer, but does not have a discontinuity associated with an integer number of electrons. Type 2 flat planes are rare—we observed just 15 type 2 flat-planes conditions out of the 4884 cases we tested—but their mere existence has implications for the design of exchange-correlation energy density functionals. To facilitate the development of functionals that have the correct behavior with respect to both fractional number of electrons and fractional spin polarization, we present a dataset for the chromium atom and its ions that can be used to test new functionals.
Superconducting radio-frequency resonator in magnetic fields up to 6 T
Authors: Ebrahimi M. S. , Stallkamp N. , Quint W. , Wiesel M. , Vogel M. , Martin A. , Birkl G.
Published: July 2016

We have measured the characteristics of a superconducting radio-frequency resonator in an external magnetic field. The magnetic field strength has been varied with 10 mT resolution between zero and 6 T. The resonance frequency and the quality factor of the resonator have been found to change significantly as a function of the magnetic field strength. Both parameters show a hysteresis effect which is more pronounced for the resonance frequency. Quantitative knowledge of such behaviour is particularly important when experiments require specific values of resonance frequency and quality factor or when the magnetic field is changed while the resonator is in the superconducting state.
Potential of mean force and transient states in polyelectrolyte pair complexation
Authors: Xu Xiao , Kanduč Matej , Wu Jianzhong , Dzubiella Joachim
Published: July 2016

The pair association between two polyelectrolytes (PEs) of the same size but opposite charge is systematically studied in terms of the potential of mean force (PMF) along their center-of-mass reaction coordinate via coarse-grained, implicit-solvent, explicit-salt computer simulations. The focus is set on the onset and the intermediate transient stages of complexation. At conditions above the counterion-condensation threshold, the PE association process exhibits a distinct sliding-rod-like behavior where the polymer chains approach each other by first stretching out at a critical distance close to their contour length, then “shaking hand” and sliding along each other in a parallel fashion, before eventually folding into a neutral complex. The essential part of the PMF for highly charged PEs can be very well described by a simple theory based on sliding charged “Debye–Hückel” rods with renormalized charges in addition to an explicit entropy contribution owing to the release of condensed counterions. Interestingly, at the onset of complex formation, the mean force between the PE chains is found to be discontinuous, reflecting a bimodal structural behavior that arises from the coexistence of interconnected-rod and isolated-coil states. These two microstates of the PE complex are balanced by subtle counterion release effects and separated by a free-energy barrier due to unfavorable stretching entropy.
Micro digital sun sensor with linear detector
Authors: Fan Qiao-yun , Peng Jia-wen , Gao Xin-yang
Published: July 2016

In this paper, the design of a novel micro digital sun sensor is described. It relies on V-shaped slit and linear array CCD to measure sun-ray angle against two axes. A highly integrated microprogram control unit) is used to make a very simple and compact system. V-shaped slit can simplify algorithm and achieve a wider field of view. Error compensation and accurate calibration are employed to improve accuracy. Adaptive threshold and adjustable expose time further improve reliability. Experiments and flight validation show that the FOV (Field of View) of the sun sensor is ±65°  ×   ± 65° and the accuracy is 0.1° in the whole FOV. It can work reliably at an update rate of 25 Hz, while the consumption is only 200 mW. This sun sensor is proved to have a good prospect in micro/nanosatellites.
Interplay between strain, defect charge state, and functionality in complex oxides
Authors: Aschauer Ulrich , Spaldin Nicola A.
Published: July 2016

We use first-principles calculations to investigate the interplay between strain and the charge state of point defect impurities in complex oxides. Our work is motivated by recent interest in using defects as active elements to provide novel functionality in coherent epitaxial films. Using oxygen vacancies as model point defects, and CaMnO3 and MnO as model materials, we calculate the changes in internal strain caused by changing the charge state of the vacancies, and conversely the effect of strain on charge-state stability. Our results show that the charge state is a degree of freedom that can be used to control the interaction of defects with strain and hence the concentration and location of defects in epitaxial films. We propose the use of field-effect gating to reversibly change the charge state of defects and hence the internal strain and corresponding strain-induced functionalities.
Global bifurcations in fractional-order chaotic systems with an extended generalized cell mapping method
Authors: Liu Xiaojun , Hong Ling , Jiang Jun
Published: July 2016

Global bifurcations include sudden changes in chaotic sets due to crises. There are three types of crises defined by Grebogi et al. [Physica D 7, 181 (1983)]: boundary crisis, interior crisis, and metamorphosis. In this paper, by means of the extended generalized cell mapping (EGCM), boundary and interior crises of a fractional-order Duffing system are studied as one of the system parameters or the fractional derivative order is varied. It is found that a crisis can be generally defined as a collision between a chaotic basic set and a basic set, either periodic or chaotic, to cause a sudden discontinuous change in chaotic sets. Here chaotic sets involve three different kinds: a chaotic attractor, a chaotic saddle on a fractal basin boundary, and a chaotic saddle in the interior of a basin and disjoint from the attractor. A boundary crisis results from the collision of a periodic (or chaotic) attractor with a chaotic (or regular) saddle in the fractal (or smooth) boundary. In such a case, the attractor, together with its basin of attraction, is suddenly destroyed as the control parameter passes through a critical value, leaving behind a chaotic saddle in the place of the original attractor and saddle after the crisis. An interior crisis happens when an unstable chaotic set in the basin of attraction collides with a periodic attractor, which causes the appearance of a new chaotic attractor, while the original attractor and the unstable chaotic set are converted to the part of the chaotic attractor after the crisis. These results further demonstrate that the EGCM is a powerful tool to reveal the mechanism of crises in fractional-order systems.
Effect of Mo insertion layers on the magnetoresistance and perpendicular magnetic anisotropy in Ta/CoFeB/MgO junctions
Authors: Almasi H. , Xu M. , Xu Y. , Newhouse-Illige T. , Wang W. G.
Published: July 2016

The effect of a thin Mo dusting layer inserted at the interface of Ta/CoFeB of perpendicular magnetic tunneling junction with MgO barriers was investigated. Unlike thick Mo layers that exhibited a strong (110) crystalline texture, the inserted Mo layer between Ta/CoFeB had little negative influence on the crystallization of CoFe (001), therefore combining the advantages of Mo as a good thermal barrier and Ta as a good boron sink. For optimized Mo dusting thickness, a large tunneling magnetoresistance of 208% was achieved in perpendicular magnetic tunneling junctions with superior thermal stability at 500 °C.
Power generation study of luminescent solar concentrator greenhouse
Authors: Corrado Carley , Leow Shin Woei , Osborn Melissa , Carbone Ian , Hellier Kaitlin , Short Markus , Alers Glenn , Carter Sue A.
Published: July 2016

A Luminescent Solar Concentrator (LSC) greenhouse and an identical control greenhouse were constructed with photovoltaic (PV) cells attached to the roof panels of both structures. The placement and types of PV cells used in the LSC panels were varied for performance comparisons. Solar power generation was monitored continuously for one year, with leading LSC panels exhibiting a 37% increase in power production compared to the reference. The 22.3 m2 greenhouse was projected to generate a total of 1342 kWh per year, or 57.4 kWh/m2 if it were composed solely of the leading panel of Criss Cross panel design. The LSC panels showed no signs of degradation throughout the trial demonstrating the material's robustness in field conditions.
Magnetic propulsion of robotic sperms at low-Reynolds number
Authors: Khalil Islam S. M. , Fatih Tabak Ahmet , Klingner Anke , Sitti Metin
Published: July 2016

We investigate the microswimming behaviour of robotic sperms in viscous fluids. These robotic sperms are fabricated from polystyrene dissolved in dimethyl formamide and iron-oxide nanoparticles. This composition allows the nanoparticles to be concentrated within the bead of the robotic sperm and provide magnetic dipole, whereas the flexibility of the ultra-thin tail enables flagellated locomotion using magnetic fields in millitesla range. We show that these robotic sperms have similar morphology and swimming behaviour to those of sperm cells. Moreover, we show experimentally that our robotic sperms swim controllably at an average speed of approximately one body length per second (around 125 μm s−1), and they are relatively faster than the microswimmers that depend on planar wave propulsion in low-Reynolds number fluids.
Collisional relaxation of bi-Maxwellian plasma temperatures in magnetized plasmas
Authors: Yoon Peter H.
Published: July 2016

In the literature, collisional processes are customarily discussed within the context of the Boltzmann-Balescu-Lenard-Landau type of collision integral, but such an equation is strictly valid for unmagnetized plasmas. For plasmas immersed in the ambient magnetic field, the foundational equation that describes binary collisions must be generalized to include the effects of magnetic field. The present paper makes use of such an equation in order to describe the collisional relaxation of temperatures under the assumption of bi-Maxwellian velocity distribution function. The formalism derived in the present paper may be useful for studying the effects of binary collisions on the isotropization of temperatures in the solar wind plasma, among possible applications.
Observation of low voltage driven green emission from erbium doped Ga2O3 light-emitting devices
Authors: Chen Zhengwei , Wang Xu , Zhang Fabi , Noda Shinji , Saito Katsuhiko , Tanaka Tooru , Nishio Mitsuhiro , Arita Makoto , Guo Qixin
Published: July 2016

Erbium doped Ga2O3 thin films were deposited on Si substrate by pulsed laser deposition method. Bright green emission (∼548 nm) can be observed by naked eye from Ga2O3:Er/Si light-emitting devices (LEDs). The driven voltage of this LEDs is 6.2 V which is lower than that of ZnO:Er/Si or GaN:Er/Si devices. Since the wide bandgap of Ga2O3 contain more defect-related level which will enhance the effects of recombination between electrons in the defect-related level and the holes in the valence band, resulting in the improvement of the energy transfer to Er ions. We believe that this work paves the way for the development of Si-based green LEDs by using wide bandgap Ga2O3 as the host materials for Er3+ ions.
Time-resolved photoluminescence characterization of oxygen-related defect centers in AlN
Authors: Genji Kumihiro , Uchino Takashi
Published: July 2016

Time-resolved photoluminescence (PL) spectroscopy has been employed to investigate the emission characteristics of oxygen-related defects in AlN in the temperature region from 77 to 500 K. Two PL components with different decay constants are observed in the near-ultraviolet to visible regions. One is the PL component with decay time of <10 ns and its peak position shifts to longer wavelengths from ∼350 to ∼500 nm with increasing temperature up to 500 K. This PL component is attributed to the radiative relaxation of photoexcited electrons from the band-edge states to the ground state of the oxygen-related emission centers. In the time region from tens to hundreds of nanoseconds, the second PL component emerges in the wavelength region from 300 to 400 nm. The spectral shape and the decay profiles are hardly dependent on temperature. This temperature-independent PL component most likely results from the transfer of photoexcited electrons from the band-edge states to the localized excited state of the oxygen-related emission centers. These results provide a detailed insight into the radiative relaxation processes of the oxygen-related defect centers in AlN immediately after the photoexcitation process.
A rapid and simple method to draw polyethylene nanofibers with enhanced thermal conductivity
Authors: Ma Jian , Zhang Qian , Zhang Yin , Zhou Lei , Yang Juekuan , Ni Zhonghua
Published: July 2016

We report on a rapid and simple method to fabricate polyethylene (PE) nanofibers by one-step drawing from PE solution. The diameter of the fiber prepared with this method can be as small as 40 nm. The thermal conductivity of the drawn PE nanofiber was measured with suspended microdevices, and the highest value obtained is 8.8 W m−1 K−1, which is very close to that of electrospun PE nanofibers, and over 20 times higher than bulk value. Raman spectra of these drawn PE nanofibers indicate that molecular chains in these fibers can be as well aligned as that in electrospun fibers, which results in the enhanced thermal conductivity of the drawn PE nanofibers.
Growth and characterization of van der Waals heterostuctures formed by the topological insulator Bi2Se3 and the trivial insulator SnSe2
Authors: Matetskiy A. V. , Kibirev I. A. , Zotov A. V. , Saranin A. A.
Published: July 2016

The formation, structure and electronic properties of SnSe2–Bi2Se3 van der Waals heterostructures were studied. Both heterostructures, SnSe2 on Bi2Se3 and Bi2Se3 on SnSe2, were grown epitaxially with high crystallinity and sharp interfaces. Their electron band structures are of trivial and topological insulators, respectively. The Dirac surface states of Bi2Se3 survive under the SnSe2 overlayer. One triple layer of SnSe2 was found to be an efficient spacer for separating a Bi2Se3 topological-insulator slab into two and creating the corresponding topological surface states.