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Two novel hybrid compounds, [{Mo(NO3)2(2,2′-bpy)}0.5{Mo6O17(2,2′-bpy)6}][PMo12O40] (1); [{Mn(2,2′-bpy)2}0.5{Mo6O17(2,2′-bpy)6}][PMo12O40] (2) (bpy = 2,2′-bpyridine), have been synthesized under mild hydrothermal conditions and structurally characterized by physico-chemical and series of spectroscopic methods. Two rare compounds which are basically isostructural with similar cell parameters are composed of transition metal-oxide-based cluster cations (TMOC) and classical Keggin type {PMo12O40} anions. Both [{Mo(NO3)2(2,2′-bpy)}0.5{Mo6O17(2,2′-bpy)6}]n and [{Mn(2,2′-bpy)2}0.5{Mo6O17(2,2′-bpy)6}]n cluster cation fragments possess opened railway molybdenum-oxide-based infinite cation chains. Then through O⋯O bond interactions, the adjacent railway chains are linked together with inverse symmetry mode to generate two kinds of interesting 2D supramolecular positive layers accommodated with big ellipse {PMo12O40} anions. By H-bonding interactions, the alternative accumulations between layers and layers give rise to 3D supramolecular channel frameworks, and the {PMo12O40} anions from different layers each other also generate graphene-like negative inorganic sheets. The electrochemical behaviors and electrocatalytic activities of both compounds have been explored. The photocatalytic activities of compounds 1 and 2 for decomposition of rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) under UV irradiation also have been investigated. The catalytic performances for the tertbutyl hydroperoxide (TBHP) oxidation of styrene also were carried out. The results show that compounds 1 and 2 exhibit multifunctional catalytic performances.

Inspired by the lubrication mechanism of human articular cartilage tissue, the porous self-lubricating polyurethane (PU) materials with micron-meter pore were fabricated by non-solvent induced phase separation (NIPS) method with 60 wt% N,N-dimethylformamide (DMF) as a coagulation agent. The scanning electron microscopic (SEM) images demonstrated that the cross-section morphology of the materials is similar to that of the sponge and adjacent macropores were connected by interpenetrating pores to exhibit an ‘ink-bottle’ type pore structure. Meanwhile, the porosity of the porous self-lubricating PU materials could be controlled by adjusting the PU solution concentrations and the oil content increased as the increasing of porosity. The results of centrifugation/heating test indicated that the porous self-lubricating PU materials have an excellent oil retention performance owing to the pore structure. The tribological properties of porous self-lubricating materials with different porosity under various loads and sliding velocities were investigated by a block-on-ring wear tester which revealed that excellent friction reduction and wear resistance properties of the porous self-lubricating materials were achieved by the lubricating oil squeezed from pores which the friction coefficient of the materials significantly reduced, from 0.174 to 0.078 with the increases of oil content. Furthermore, the lubrication mechanism of porous self-lubricating PU material was discussed as well.

A new organic–inorganic hybrid compound contained bi-capped Bi Keggin anion, [biim][PMo 1 V Mo 11 VI Bi1.24O40]·3H2O (1) (biim = biimidazole) has been firstly synthesized and characterized by IR, UV–Vis, XRD, XPS, elemental analyses, fluorescent spectrum and TG analysis. Compound 1 exhibits a novel 2-D supramolecular network structure constructed from {PMo 1 V Mo 11 VI Bi1.24O40} anions by O···O interactions, and further extends a 3-D supramolecular framework by bridges of biimidazole with N–H···O hydrogen bonding interactions. The compound 1 performs well catalytic property for epoxidation of styrene to styrene oxide. Moreover, compound 1 displays excellent photodegradation activity for methyl orange dye.

Three POM-based host–guest compounds constituted by Keggin-type polyoxometalates (POMs): (4,4′-Hbpy)3 [PMo12O40]·2H2O (1); (4,4′-H2bpy)3[PMo12O40]2·3H2O (2) and (4,4′-H2bpy) (4,4′-Hbpy)·[PW12O40]·4H2O (3) (bpy = 4,4′-bpyridine) have been synthesized hydrothermally and characterized by elemental analyses, IR, XPS spectra, powder XRD analyses, cyclic voltammetric measurements and single-crystal X-ray diffraction analyses. The three compounds all consist of Keggin-type POMs and 4,4′-bpy ligand, which are [PMo12O40]3− for 1–2 and [PW12O40]3− for 3. Through O···O interactions, Keggin POMs each other give rise to three different 3-D Supermolecular host structures, 4,4′-bpy and water molecules as guests accommodate different channels with H-bonding interactions. Discuss the pH role for the build POM based-hybrids contained 4,4′-bpy ligand. The photocatalytic properties of 1–3 have been investigated in the solid state.

The Monte-Carlo rough surface code SURO is applied for the simulation of the carbon deposition and substrate erosion on rough surfaces. The energy, flux and angle of impinging particles calculated by the SDPIC code are employed as the input for the SURO simulations. The study of the carbon deposition and substrate erosion on different surface structures has been carried out with different plasma temperatures. The temporal evolution of the eroded substrate areal density on tungsten and carbon substrates has been studied under different plasma temperatures, which reveals that the material mixing process has an impact on the erosion of substrate material. For the plasma temperature of 10 eV, the eroded areal density for the tungsten substrate is about 1019 m−2, which is two orders of magnitude lower than that for the carbon substrate. As the plasma temperature increases to 20 eV, the discrepancy in the eroded substrate areal density between the tungsten and carbon substrates is reduced, i.e., one order of magnitude lower for the tungsten substrate.

A comparative investigation of heat stress-mediated physiological and biochemical parameters in conjunction with the expression analysis of heat shock transcription factors (BrHSF) from two different Chinese cabbage genotypes was done to understand the mechanism of heat tolerance. Our results show that the heat-tolerant (2013-33) genotype had a smaller relative electric conductivity, a less malondialdehyde content and a higher maximal efficiency of photosystem II photochemistry than the heat-sensitive (AM160) genotype, and was able to develop the leaf head under heat stress, whereas 'AM160' flailed to develop it. The results also indicate that '2013-33' accumulated a higher amount of soluble sugars and protein under heat stress condition than 'AM160'. However, it warrants to mention that proline content and antioxidant enzymes, such as the peroxidase, catalase, and superoxide dismutase activities, in the 2013-33 genotype under HS were recorded, being significantly lower than in 'AM160'. Additionally, the expression profile of BrHSF genes was checked and classified to three main groups, (i) HS-induced HSFs expressed in both genotypes ( group I), (ii) suppressed by HS in both genotypes (groupII), and (iii) genotype-specific expression of HSFs (repressed in the AM160 heat-sensitive genotype whereas induced in the '2013-33' heat tolerance genotype; group III). Furthermore, the result of promoter analysis shows that group III BrHSFs, i.e., 23, 30, and 33 gene promoter regions possessed a difference between '2013-33' and 'AM160'. In conclusion, the results of our study identify that '2013-33' had more heat tolerance than 'AM160' because of a higher accumulation of sugar and protein and an enhanced expression of group III HSFs, and the differential response of group III HSFs to HS in these two genotypes may be because of a promoter sequence difference. The study provides us a clue towards understanding the mechanism of heat tolerance in Chinese cabbage and offers a valuable source for further improvement of heat tolerance in Chinese cabbage.

We investigate the electrical control of magnetization and exchange bias in Pt/Co/Ni/HfO2 films gated by ionic liquid. Results show that saturated magnetization of Co/Ni can be significantly manipulated under finite voltages at room temperature. Unlike the conventional electrostatic effect, the electric gating here exhibits dynamic and nonvolatile features clearly. Hence, an electrochemical mechanism is proposed naturally and the analysis of chemical states of Ni and Co confirms the reversible oxygen ion migration across the interface between HfO2 and Co/Ni under gate voltages. Furthermore, robust exchange bias is observed below 200 K and both the bias field and coercive field can be prominently modulated in Pt/Co/Ni/HfO2 under electric field, resulting from gate voltage dependent content of antiferromagnetic oxidation products of Ni and Co. The demonstration of oxygen ion migration in ferromagnetic metals/oxides heterostructures followed by magnetization modulation at room temperature might pave the way ...

Manipulation of oxygen vacancies (V_O) in single oxide layers by varying the electric field can result in significant modulation of the ground state. However, in many oxide multilayers with strong application potentials, e.g. ferroelectric tunnel junctions and solid-oxide fuel cells, understanding V_O behaviour in various layers under an applied electric field remains a challenge, owing to complex V_O transport between different layers. By sweeping the external voltage, a reversible manipulation of V_O and a corresponding fixed magnetic phase transition sequence in cobaltite/manganite (SrCoO3-x/La0.45Sr0.55MnO3-y) heterostructures are reported. The magnetic phase transition sequence confirms that the priority of electric-field-induced V_O formation/annihilation in the complex bilayer system is mainly determined by the V_O formation energies and Gibbs free energy differences, which is supported by theoretical analysis. We not only realize a reversible manipulation of the magnetic phase transition in an oxide bilayer, but also provide insight into the electric field control of V_O engineering in heterostructures., 30 pages, 7 figures

The intrinsic brittleness and ductility of intergranular cracks in Cu bicrystals under quasi-static loading conditions are investigated using molecular statics simulations. Central cracks are inserted into nine Σ11\( [1 \, 1 \, 0] \) tilt grain boundaries with different inclination angles, seven of which are asymmetric, and two of which are symmetric. On the basis of results of molecular statics simulations, critical energy release rates at material failure are calculated using the corresponding continuum counterparts with the finite element method. Simulation results are compared to predictions made on the basis of Rice’s model, and the applicable range of Rice’s model is given in terms of inclination angle. The effects of inclination angle on the mechanical properties of grain boundaries and fracture mechanisms of the corresponding intergranular cracks are analyzed in detail.

We report the reversible orbital reconstruction driven by ferroelectric polarization modulates the magnetic performance of ferroelectric/ferromagnetic heterostructure. Inplane Mn orbital occupancy and related interfacial magnetic state are enhanced and weakened by the negative and positive electric-field, respectively. With the aid of ionic liquid, the modulation of magnetism extends to bulk part of the ferromagnet. Our finding not only shows the role of orbits on electrical control of magneism, but also makes the orbits straight forward to the application in microelectronic device.

The rheological kinetics of konjac glucomannan and gellan gum mixed sols were studied using rotational concentric cylinder viscometer. The effects of polymers weight ratio, shear rate, and temperature were systematically investigated. The curves showed a Newtonian plateau followed by strong shear thinning that can be described by a power law dependence on the shear rate. The dynamic viscoelastic character was evaluated by measurements of small-deformation oscillatory. After adding some cations, the mixed sols turned into mixed gels. The contribution of Na+, K+, Ca2+, and Zn2+ at different concentration was also evaluated by texture analysis. The results reveal a strong dependence of the structural properties of different samples on their preparation conditions. A fine turning of the properties of the mixed sols is possible through the change of the temperature preparation and/or the polymer weight ratio. The texture properties of the mixed gels were also possibly influenced significantly by the cations. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Laser cladding of the Ti3Al + TiB2 pre-placed alloy powder on the Ti–6Al–4 V alloy in nitrogen protective atmosphere can form the Ti3Al + TiB2/TiN composite coating, which can dramatically improve the wear resistance of the Ti–6Al–4 V alloy surface. In this study, the Ti3Al + TiB2/TiN composite coatings on the Ti–6Al–4 V alloy have been researched by means of X-ray diffraction, SEM and energy dispersive spectrometry. It was found that there is a metallurgical combination between the Ti3Al + TiB2/TiN composite coating and the substrate. The microhardness of the Ti3Al + TiB2/TiN composite coatings were 3 ~ 4 times higher than that of the Ti–6Al–4 V alloy because of the actions of the Ti3Al + TiB2/TiN hard phases and the grain refinement strengthening. Moreover, the wear mass losses of the Ti3Al + TiB2/TiN composite coatings were much lower than that of the substrate. Copyright © 2011 John Wiley & Sons, Ltd.

A non‐destructive ultrasonic attenuation measurement is adopted to characterise the state of polymers in the cavity during injection moulding. According to the relationship between ultrasonic attenuation behaviours and polymer viscosity, elasticity transition as well as crystallisation, the evolution of ultrasonic attenuations for an amorphous polymer (general purpose polystyrene) and a crystalline polymer (polypropylene) were discussed. Experimental results show that the ultrasonic attenuation measurement can not only provide information of the amorphous polymer on filling start, filling stop, elasticity transition and detachment from the mould, but can also extract information of crystallisation for the crystalline polymer throughout the injection moulding process. The ultrasonic attenuation measurement is a potential candidate technology to characterise the state of polymers in the cavity and thereby optimise the injection moulding process for perfect products.

FCC-Co/Al(2)O(3) and FCC-Co/Y(2)O(3) nanocapsules were prepared by a modified arc-discharge technique, which exhibited the maximum magnetic resonance (mu") peak at the same frequency of 6.4 GHz. For the FCC-Co/Al(2)O(3) nanocapsules, the reflection loss being less than -20 dB was obtained in the frequency range of 9.6-11 GHz with an absorber thickness of 4-5 mm, while a minimum reflection loss of -29.7 dB was achieved at 10 GHz with an absorber thickness of 5 mm. The FCC-Co/Y(2)O(3) nanocapsules are with broader frequency range (9.7-12.4 GHz) and thinner matching thickness (2-4 mm) for RL < -20 dB, due to comparatively higher magnetization. The FCC-Co/Al(2)O(3) and FCC-Co/Y(2)O(3) nanocapsules may become attractive candidates for a new type of electromagnetic wave absorptive materials. (C) 2008 Elsevier Ltd. All rights reserved.

The cDNA of Insulin-like growth factor binding protein 3 was subcloned into a eukaryotic secretory expression vector pSectagA to construct pSectag-IGFBP3. Human renal cell carcinoma (RCC) 786-0 cells were transfected with pSectag-IGFBP3 using lipofectamine 2000. After 48 h, the secretory IGFBP-3 was tested and identified by western blotting. Meanwhile, Annexin V-EGFP stain was used to analyze the apoptosis of 786-0 cells induced by IGFBP-3. Secretory IGFBP-3 protein could express successfully in the 786-0 cells and the expressed IGFBP-3 directly displayed an apoptotic effect on the host cells. This work provides a basis for further study on the apoptosis-inducing mechanism of IGFBP-3 and the development of a new anti-tumor drug.

Antiferromagnetic spin-flop transitions in a series of λ-(BETS)2FeBrxCl4-x are observed using piezoresistive AFM microcantilever. The measurements are carried out on a tiny single crystal using a sample rotator and the easy axis changes with increasing the bromine content x. The Neel temperature and spin-flop transition field also rise with increasing the bromine content x, suggesting an enhancement of π-d interactions by replacement of chlorine with bromine atoms in this mixed-halide anion system.

With the recent realization of hybrid improper ferroelectricity and room-temperature multiferroic by tilt engineering, “functional” octahedral tilting has become a novel concept in multifunctional perovskite oxides, showing great potential for property manipulation and device design. However, the control of magnetism by octahedral tilting has remained a challenging issue. Here a qualitative and quantitative tilt engineering of exchange coupling, one of the magnetic properties, is demonstrated at compensated G-type antiferromagnetic/ferromagnetic (SrMnO3/La2/3Sr1/3MnO3) interfaces. According to interfacial Hamiltonian, exchange bias (EB) in this system originates from an in-plane antiphase rotation (a−) in G-type antiferromagnetic layer. Based on first-principles calculation, tilt patterns in SrMnO3 are artificially designed in experiment with different epitaxial strain and a much stronger EB is attained in the tensile heterostructure than the compressive counterpart. By controlling the magnitude of octahedral tilting, the manipulation of exchange coupling is even performed in a quantitative manner, as expected in the theoretical estimation. This work realized the combination of tilt engineering and exchange coupling, which might be significant for the development of multifunctional materials and antiferromagnetic spintronics.

We report results of 77 Se NMR study for a newly found field-induced superconductor, κ-(BETS) 2 FeBr 4 . The nuclear spin lattice relaxation rate (1/T 1 ) above 25 K has a linear relation with temperature, 1/ T 1 = a T +b, which can be analyzed in a framework of normal metal with dipolar fields from uncorrelated 3 d local moments to the Se nuclei. However, 1/T 1 has an evident kink at 25 K and shows a remarkable decrease within a narrow temperature range of 2.5 K. Below 22.5 K, we found that 1/ T 1 follows a power law 1/ T 1 ∼ T 1.43 , although the material is still conductive. The temperature where 1/ T 1 shows a kink agrees with the temperature where the temperature devivative of the resistivity dρ/d T diverses. We discuss a possible reconstruction of the electronic state, which may attain magnetic correlation below this temperature.

Real time detection of vitellogenin in largemouth bass serum was demonstrated using AlGaN/GaN HEMTs. Anti-vitellogenin antibodies were chemically anchored to the gold-coated gate area of the HEMT by thioglycolic acid. The potential difference that occurred from the vitellogenin antigen/antibody interaction induced a drain current change. The sensor was able to detect as low as 4 µg/mL Vtg. Successful detection in serum samples shows that HEMTs have the potential to be used as biological sensors in real-world applications (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The interplay between orbital, charge, spin, and lattice degrees of freedom is at the core of correlated oxides. This is extensively studied at the interface of heterostructures constituted of two-layer or multilayer oxide films. Here, we demonstrate the interactions between orbital reconstruction and charge transfer in the surface regime of ultrathin (La,Sr)MnO3, which is a model system of correlated oxides. The interactions are manipulated in a quantitative manner by surface symmetry-breaking and epitaxial strain, both tensile and compressive. The established charge transfer, accompanied by the formation of oxygen vacancies, provides a conceptually novel vision for the long-term problem of manganites--the severe surface/interface magnetization and conductivity deterioration. The oxygen vacancies are then purposefully tuned by cooling oxygen pressure, markedly improving the performances of differently strained films. Our findings offer a broad opportunity to tailor and benefit from the entanglements between orbit, charge, spin, and lattice at the surface of oxide films.

We have developed off-line experimental techniques and apparatuses that permit direct measurement of effusive-flow delay times and ionization efficiencies for nearly any chemically reactive element in high-temperature target/ion sources (TIS) commonly used for on-line radioactive ion-beam (RIB) generation. The apparatuses include a hot Ta valve for effusive-flow delay-time measurements, a cooled molecular injection system for determination of ionization efficiencies, and a gas flow measurement/control system for introducing very low, well-defined molecular flows into the TIS. Measurements are performed on a test stand using molecular feed compounds containing stable complements of the radioactive nuclei of interest delivered to the TIS at flow rates commensurate with on-line RIB generation. In this article, the general techniques are described and effusive-flow delay times and ionization efficiency measurements are reported for fluorine in an electron-beam plasma target/ion source developed for RIB generation and operated in both positive- and negative-ion extraction modes.

A versatile, new concept, spherical-geometry, positive (negative) surface-ionization source has been designed, fabricated, and initial tests completed which can operate in either positive- or negative-ion beam generation modes without mechanical changes to the source. The highly permeable, composite Ir/C has an intrinsic work function of φ=5.29 eV and can be used directly for the generation of positive-ion beams of highly electropositive elements. For negative-surface ionization, the work function is lowered by dynamic flow of a highly electropositive adsorbate such as Cs through the ionizer matrix. The results of initial testing indicate that the source is reliable, stable and easy to operate, with efficiencies for Cs+ conservatively estimated to exceed 60% and as high as ∼50% for F− generation. However, the overall ionization efficiency for F− formation and extraction is ∼1% due to the low efficiency for thermal dissociation of the carrier molecules (assumed to be CsF and AlF). The design features, operational principles, and initial performance of the source for generating Cs+ and F−, when operated with Cs, are discussed in this article.

Radioactive ion beams (RIBs) of 17F and 18F are of interest for investigation of astrophysical phenomena such as the “hot” CNO cycle and the rp stellar nuclear synthesis processes. In order to generate useful beam intensities of atomic F−, the species must be efficiently and expediently released from the target material, thermally dissociated from fluoride release products during transport to the ionization chamber of the ion source, and efficiently ionized in the source upon arrival. We have conceived and evaluated two prototype negative-ion sources for potential use for RIB generation: (1) a direct extraction source and (2) a kinetic-ejection source. Both sources utilize Cs vapor to enhance F− formation. The mechanical design features, operational parameters, ionization efficiencies for forming atomic F−, and delay times for transport of F and fluoride compounds for the respective sources are presented. The efficiency η for formation and extraction of F− for the direct extraction negative-ion source is ...

A new pretreatment method involving a direct current discharge was used to enhance diamond nucleation on mirror polished silicon substrates employing hot filament chemical vapor deposition. A nucleation density of 108/cm2 was obtained. The nucleation density on Si substrates pretreated by the discharge at room temperature is similar to that treated at high temperature. The discharge process was monitored by optical emission spectroscopy. Raman scattering, scanning electron microscopy, and x-ray photoelectron spectroscopy were employed to analyze the pretreated Si substrate. The results suggest that a thin carbon layer formed during the discharge pretreatment process which contributes to the enhancement of diamond nucleation.

We demonstrate that the uniaxial magnetic anisotropy (UMA) of amorphous CoFeB films can be tuned by crystallinity and orbital moment ratio, combining the results of magnetization reversal and ferromagnetic resonance with high-resolution transmission electron microscopy, x-ray-absorption near-edge structure and x-ray magnetic circular dichroism. Isotropic polycrystalline buffers of tungsten (W), tantalum (Ta), and copper (Cu) between CoFeB and Si(100) substrates have direct and crucial bearing on the interfacial microstructure and orbital moment ratio. Compared with Ta and Cu buffer, CoFeB with W buffer exhibits obvious UMA and has lower crystallinity at the interface and higher orbital moment. Amorphous phase distributed homogeneously in CoFeB film grown on W buffer contributes to improve the easy-axis squareness with a sharp magnetization reversal. Our demonstrations not only realize effective tuning of UMA in amorphous CoFeB, but also provide an appealing alternative buffer (W) for CoFeB-based magnetic tunnel junctions.

In situ optical emission spectroscopy has been used to measure the direct current biased hot-filament diamond deposition processes for gas mixtures of methane, argon and hydrogen. The effects of bias on diamond growth and optical emission were investigated. The increase of bias voltage slightly raises the atomic hydrogen concentration which is estimated by using the Ar (750 nm) line as actinometry. The bias has little influence on hydrocarbon species and electron temperature. The enhancement of diamond nucleation and smoothing of the film surface by positive bias are mainly caused by electron bombardment on the surface of the substrate and growing film rather than on the change of gaseous environment.

A series of new magnetic organic conductors consisting of it donors with stable organic radical part and inorganic anions was prepared. The air-stable TTP derivatives containing a PROXYL radical were synthesized by phosphite-based cross-coupling reaction of 1,3-dithiol-2-one derivatives and the thione containing a PROXYL radical. The ClO 4 and FeCl 4 salts of TTP-PROXYL were electrochemically prepared. Besides the 2:1 salts with fairly high conductivity (D 2 A; D=radical donor, A= anion), there is a semiconducting 1:1 complex (TTP-PROXYL)FeCl 4 (σ(RT) = 10 -3 Ω -1 cm -1 , E = 0.12 eV). The temperature dependence of the susceptibilities suggests the coexistence of n-radical spins (S=1/2) and Fe 3+ magnetic moments (S=5/2). The system with non-magnetic ions, (TTP-PROXYL) GaCl 4 and (CpTTP-PROXYL)AsF 6 salts were also examined.

A soil column method was used to analyse the characteristics of the movement and transformation of potassium (K) in a latosol. The internal temperature was maintained at 28 to 30 °C. The distances moved by the added K were 50 to 100 mm after 7 and 28 d, respectively. Potassium moved faster within 7 d during the incubation time of 28 d. The concentrations of water-extractable K, and exchangeable K, had significant negative linear relationships with distance from fertiliser placement in the region of K movement. In incubation time, water-extractable K and exchangeable K had significant effects on the concentration distributions for fertiliser micro-sites, but had no significant effects on non-exchangeable K. Most of K was still in an available form at fertiliser micro-sites after moving into the soil except that 4.22% to 11.19% of all applied K was fixed by soil.

Inserting a positively biased electrode to just inside the Phaedrus-T tokamak limiter results in typical H mode behaviour (i.e. Hα or Dα drop, density rise, increase in stored energy, profile steepening, and reduction of edge turbulence and radial transport) in deuterium, hydrogen and helium discharges. Hα or Dα emission suggests that the improvement in particle confinement with H mode is poloidally asymmetric, with the greatest improvement occurring on the low field side. The radial conductivity is examined and measured values are compared with theory

We investigate the electrical manipulation of the phase transition in ultrathin FeRh films through a combination of ionic liquid and oxide gating. The 5 nm-thick FeRh films show an antiferromagnetic-ferromagnetic transition at around 275 K with in-plane magnetic field of 70 kOe. A negative gate voltage seriously suppresses the transition temperature to ∼248 K, while a positive gate voltage does the opposite but with a smaller tuning amplitude. The formation of electric double layer associated with a large electric field induces the migration of oxygen ions between the oxide gate and the FeRh layer, producing the variation of Fe moments in antiferromagnetic FeRh accompanied by the modulation of the transition temperature. Such a modulation only occurs within several nanometers thick scale in the vicinity of FeRh surface. The reversible control of FeRh phase transition by electric field might pave the way for non-volatile memories with low power consumption.

A new anti-neoplastic spirostanol saponin, (25S)-spirost-5-en-3 beta, 27-diol-3O-[alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl (1-->3)]-beta-D-glucopyranoside and three known compounds viz. prosapogenin A of dioscin, dioscin and gracilin were isolated from Dioscorea futschauensis by bioactivity-guided fractionation. Their structures were elucidated mainly by means of spectroscopic analysis. Their bioactivity against Pyricularia oryzae and cytotoxic activity on ts-FT210 cell line was evaluated.

TLC/HPLC methods for determining the individual amounts of corosolic and maslinic acids in the extract of Lagerstroemia speciosa leaves have been developed. The leaves of L. speciosa were extracted with methanol, followed by partition between CHCl3 and water, then separated using TLC on silica gel, and evaluated quantitatively by HPLC. The HPLC analysis was performed with an acetonitrile − 0.1% aqueous phosphoric acid mixture (60: 40) at a flow rate of 1 ml/min in an isocratic regime. The regression equations of the analytical curves and their coefficients of determination (R2) were calculated as follows: corosolic acid, y = 6627.9x + 2.6725 (R2 = 0.9998); maslinic acid, y = 6528.1x + 4.568 (R2 = 0.9995).

We investigate the control of orbital occupancy by ferroelectric polarization in LaNiO3/BaTiO3−δ heterostructures. It is achieved by the ferroelectric displacement of Ti ions polarized downward (upward) to form (break) Ni–O–Ti covalent bonding at the interface, accompanied by charge transfer between them and the modulation of the conductivity of ultrathin LaNiO3. This electrically switchable and bi-direction control of orbital polarization in LaNiO3 is up to 25%, different from the manipulation by epitaxial strain or quantum confinement. Our finding opens a window for electrical control of orbital polarization at an oxide interface.

We investigate the electrical manipulation of Co/Ni magnetization through a combination of ionic liquid and oxide gating, where HfO2 with a low O2− ion mobility is employed. A limited oxidation-reduction process at the metal/HfO2 interface can be induced by large electric field, which can greatly affect the saturated magnetization and Curie temperature of Co/Ni bilayer. Besides the oxidation/reduction process, first-principles calculations show that the variation of d electrons is also responsible for the magnetization variation. Our work discloses the role of gate oxides with a relatively low O2− ion mobility in electrical control of magnetism, and might pave the way for the magneto-ionic memory with low power consumption and high endurance performance.

We investigate the exchange bias effect in La0.67Sr0.33MnO3/G-SrMnO3/ La0.67Sr0.33MnO3 (LSMO/SMO/LSMO) sandwiches, where the spacer is a G-type antiferromagnet. Because of the cycloid bulk spins in the SMO modulated by the top LSMO layer, the sandwich structure exhibits an oscillatory exchange bias behavior as a function of the SMO thickness. This unprecedented phenomenon vanishes in LSMO/SMO bilayers, where the exchange bias saturates as the SMO thickness increases, giving rise to the antiferromagnetic anisotropy constant of SMO, 1.0 –2.0 × 105 erg cm−3. The results provide a broad opportunity to tailor antiferromagnetic moments by interfacial design for antiferromagnet spintronics.

The authors present a laser-assisted nanotransfer printing technique for transferring metal nanopatterns onto prepatterned substrates. A fused quartz mold covered with an array of chromium nanodots is pressed against the surface of a photolithographically patterned substrate, while a single laser pulse from a quadrupled-frequency solid state Nd:YAG laser is used to melt the thin metal structures. By controlling the laser fluence, selective metal pattern transfer can be realized only on the protruded area of the substrate upon separation of the quartz support. The transferred chromium nanodots are then used as an etch mask to pattern three-dimensional structures.

A high-intensity, plasma-sputter negative-ion source based on the use of RF power for plasma generation has been developed that can be operated in either pulsed or dc modes. The source utilizes a high-Q, self-igniting, inductively coupled antenna system, operating at 80 MHz that has been optimized to generate Cs-seeded plasmas at low pressures (typically

A multi-sample Cs sputter negative-ion source, equipped with a conical-geometry, W-surface-ionizer has been designed and fabricated that permits sample changes without disruption of on-line accelerator operation. Sample changing is effected by actuating an electro-pneumatic control system located at ground potential that drives an air-motor-driven sample-indexing-system mounted at high voltage; this arrangement avoids complications associated with indexing mechanisms that rely on electronic power-supplies located at high potential. In-beam targets are identified by LED indicator lights derived from a fiber-optic, Gray-code target-position sensor. Aspects of the overall source design and details of the indexing mechanism along with operational parameters, ion optics, intensities, and typical emittances for a variety of negative-ion species will be presented in this report.

CdS nanocrystal-sensitized solar cells (NCSSCs) were investigated by using polyaniline (PANI) as a replacement for conventional platinum counter electrode. The growth time of the NCs significantly affects the solar cell performance. At an optimum growth, the NCSSCs exhibit 0.83% of the conversion efficiency in comparison to 0.13% for the identical cells without CdS NCs. Electrochemical impedance spectroscopy showed that the charge transfer in the solar cells with CdS nanocrystals was improved. The enhanced overall energy conversion efficiency by NCs is attributed to improved light absorption and suppressed recombination rate of interfacial charges with injection, resulting in significantly improved charge transfer and electron life time. In addition, the PANI electrodes with large surface area and ideal corrosion-inertness toward polysulfide redox exhibit promising application potential as a counter electrode for NCSSCs. This study demonstrates that the solution grown CdS nanocrystals and polyaniline are ...

The exchange coupling between PtFe and Fe in PtFe/Fe films with Cr2O3 or Cr2O3/Cu spacer layers is indirect and long range. Microstructures of as-deposited and annealed thin films are studied. Coercivity over 10 kOe is obtained in PtFe/Cr2O3(5 A)/Fe(25 A) films but decrease with thicker Cr2O3 spacer layer. Comparably, coercivity can be maintained at about 10 kOe if spacer layer is changed into Cr2O3(x A)/Cu(5 A) (5 A ≤ x ≤ 25 A). For a fixed total thickness of the spacer layers, the coercivity generally decreases with gradual replacement of Cr2O3 by Cu, indicating the different effects of spacer layers on mediating the exchange coupling between PtFe and Fe. Using Cr2O3 or Cr2O3/Cu as a spacer layer is a promising way for realizing exchange-coupled PtFe/Fe composite films.

The effect of interstitial nitrogen on the phase transition and magnetocaloric behavior of MnAs1−xSixNδ (x=0.03, 0.06, and 0.09) is investigated. The interstitial nitrogen atoms cause the step-scanned x-ray diffraction peaks to shift toward lower angles and lower the Curie temperature, whereas silicon addition increases the Curie temperature to near room temperature. The thermal hysteresis is reduced to nearly 0 in MnAs1−xSixNδ, which is beneficial to practical applications. For a field change of 5 T, the largest magnetic entropy change and refrigerant capacity are 14.6 J kg−1 K−1 at 247 K and 360 J kg−1, which is slightly higher than the entropy change in the parent alloy. Finally, we briefly discuss the occurrence and origin of the “virgin effect” in MnAs.

Endocrine disrupters are known to have negative effects on the environment and human health. Real time detection of vitellogenin, an endocrine disrupter biomarker, was demonstrated using AlGaN/GaN high electron mobility transistors (HEMTs). Anti-vitellogenin antibodies were chemically anchored to the gold-coated gate area of the HEMT and immobilized with thioglycolic acid. The potential difference that occurs from the vitellogenin antigen-antibody interaction-induced caused a drain current change in the HEMT. The HEMT sensor was tested for vitellogenin detection both in phosphate buffer saline and largemouth bass serum.

A simple method is reported for fabrication of AlN/GaN MOS-HEMTs. Ultra-thin Al 2 O 3 , which is formed using thermal oxidation of evaporated Al, was used for surface passivation and as a gate dielectric. Prior to formation of Al 2 O 3 , the Al protects the very sensitive AlN epilayer from exposure to processing liquid chemicals. Fabricated two-finger AlN/GaN MOS-HEMTs with 3 m gate length and 200 m gate width showed good gate control of drain currents up to a gate bias of 3 V and achieved a maximum drain current, I DSmax , of ~900~mA/mm. The peak extrinsic transconductance, G max , of the device is ~100~mS/mm at V DS = 8=V. Capacitance-voltage ( C - V ) characteristics of Al 2 O 3 /AlN/GaN circular test MOS structures were observed and measured. They exhibited no hysteresis, indicating the good quality of the thermally grown Al 2 O 3 for realising AlN/GaN MOS-HEMTs for high power and high frequency applications.

Enhancement mode AlN/GaN high electron mobility transistors (HEMTs) were fabricated from originally depletion-mode structures using oxygen plasma treatment on the gate area prior to the gate metallization. Starting with a depletion mode AlN/GaN HEMT, the threshold voltage of the HEMT could be shifted from −3.2 to 1 V depending on the oxygen plasma treatment time to partially convert the AlN barrier layer into Al oxide. The gate current was reduced and the current-voltage curves show metal-oxide semiconductor diodelike characteristics after oxygen plasma treatment.