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Sample records for room-temperature functional analogue

  1. Functional relationship of room temperature and setting time of alginate impression material

    Directory of Open Access Journals (Sweden)

    Dyah Irnawati

    2009-09-01

    Full Text Available Background: Indonesia is a tropical country with temperature variation. A lot of dental clinics do not use air conditioner. The room temperature influences water temperature for mixing alginate impression materials. Purpose: The aim of this study was to investigate the functional relationship of room temperature and initial setting time of alginate impression materials. Methods: The New Kromopan® alginate (normal and fast sets were used. The initial setting time were tested at 23 (control, 24, 25, 26, 27, 28, 29, 30 and 31 degrees Celcius room temperatures (n = 5. The initial setting time was tested based on ANSI/ADA Specification no. 18 (ISO 1563. The alginate powder was mixed with distilled water (23/50 ratio, put in the metal ring mould, and the initial setting time was measured by test rod. Data were statistically analyzed by linear regression (α = 0.05. result: The initial setting times were 149.60 ± 0.55 (control and 96.40 ± 0.89 (31° C seconds for normal set, and 122.00 ± 1.00 (control and 69.60 ± 0.55 (31° C seconds for fast set. The coefficient of determination of room temperature to initial setting time of alginate were R2 = 0.74 (normal set and R2 = 0.88 (fast set. The regression equation for normal set was Y = 257.6 – 5.5 X (p < 0.01 and fast set was Y = 237.7 – 5.6 X (p < 0.01. Conclusions: The room temperature gave high contribution and became a strength predictor for initial setting time of alginates. The share contribution to the setting time was 0.74% for normal set and 0.88% for fast set alginates.

  2. Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications

    International Nuclear Information System (INIS)

    Dong Wenjun; Huang Huandi; Zhu Yanjun; Li Xiaoyun; Wang Xuebin; Li Chaorong; Chen Benyong; Wang Ge; Shi Zhan

    2012-01-01

    A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide–amine intermediate and Ag + at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO 3 nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag–MoO 3 nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature. (paper)

  3. Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications.

    Science.gov (United States)

    Dong, Wenjun; Huang, Huandi; Zhu, Yanjun; Li, Xiaoyun; Wang, Xuebin; Li, Chaorong; Chen, Benyong; Wang, Ge; Shi, Zhan

    2012-10-26

    A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide-amine intermediate and Ag(+) at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO(3) nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag-MoO(3) nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature.

  4. Activation of room temperature ferromagnetism in ZnO films by surface functionalization with thiol and amine

    International Nuclear Information System (INIS)

    Jayalakshmi, G.; Gopalakrishnan, N.; Balasubramanian, T.

    2013-01-01

    Highlights: ► Room temperature ferromagnetism (RTFM) is observed in surface functionalized ZnO films. ► Surface functionalization is a new approach to make ZnO as ferromagnetic. ► The RTFM is attributed to the interaction between the adsorbates and the surface of ZnO. ► The oxygen vacancies are passivated upon surface functionalization. - Abstract: In this paper, we report the activation of room temperature ferromagnetism in ZnO films by surface functionalization with thiol and amine. The pure and surface functionalized ZnO films have been examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and vibrating sample magnetometer (VSM) measurements. XRD measurements show that all the films have single phase and (0 0 2) preferred orientation. The chemical bonding of ZnO with thiol and amine molecules has been confirmed by XPS measurements. The quenching of visible emission in PL spectra indicates that the surface defects are passivated by functionalization with thiol and amine. Surface functionalization of ZnO films with thiol and amine induces robust room temperature ferromagnetism in ZnO films as evidenced from VSM measurements. It is concluded that the observed ferromagnetic behavior in functionalized ZnO films is attributed to the different electronegativity of the atom in the thiol (or amine) and the surface of ZnO.

  5. Functionalized Ga2O3 nanowires as active material in room temperature capacitance-based gas sensors.

    Science.gov (United States)

    Mazeina, Lena; Perkins, F Keith; Bermudez, Victor M; Arnold, Stephen P; Prokes, S M

    2010-08-17

    We report the first evidence for functionalization of Ga(2)O(3) nanowires (NWs), which have been incorporated as the active material in room temperature capacitance gas-sensing devices. An adsorbed layer of pyruvic acid (PA) was successfully formed on Ga(2)O(3) NWs by simple room temperature vapor transport, which was confirmed by Fourier transform infrared spectroscopy. The effect of the adsorbed PA on the surface properties was demonstrated by the change in the response of the NW gas-sensing devices. Results indicate that the adsorption of PA reduced the sensitivity of the Ga(2)O(3) NW device to common hydrocarbons such as nitromethane and acetone while improving the response to triethylamine by an order of magnitude. Taking into account the simplicity of this functionalization together with the ease of producing these capacitance-based gas-sensing devices, this approach represents a viable technique for sensor development.

  6. Room-temperature antiferromagnetic memory resistor.

    Science.gov (United States)

    Marti, X; Fina, I; Frontera, C; Liu, Jian; Wadley, P; He, Q; Paull, R J; Clarkson, J D; Kudrnovský, J; Turek, I; Kuneš, J; Yi, D; Chu, J-H; Nelson, C T; You, L; Arenholz, E; Salahuddin, S; Fontcuberta, J; Jungwirth, T; Ramesh, R

    2014-04-01

    The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets.

  7. Room temperature superconductors

    International Nuclear Information System (INIS)

    Sleight, A.W.

    1995-01-01

    If the Holy Grail of room temperature superconductivity could be achieved, the impact on could be enormous. However, a useful room temperature superconductor for most applications must possess a T c somewhat above room temperature and must be capable of sustaining superconductivity in the presence of magnetic fields while carrying a significant current load. The authors will return to the subject of just what characteristics one might seek for a compound to be a room temperature superconductor. 30 refs., 3 figs., 1 tab

  8. Crystalline Microporous Organosilicates with Reversed Functionalities of Organic and Inorganic Components for Room-Temperature Gas Sensing.

    Science.gov (United States)

    Fabbri, Barbara; Bonoldi, Lucia; Guidi, Vincenzo; Cruciani, Giuseppe; Casotti, Davide; Malagù, Cesare; Bellussi, Giuseppe; Millini, Roberto; Montanari, Luciano; Carati, Angela; Rizzo, Caterina; Montanari, Erica; Zanardi, Stefano

    2017-07-26

    A deepened investigation on an innovative organic-inorganic hybrid material, referred to as ECS-14 (where ECS = Eni carbon silicates), revealed the possibility to use them as gas sensors. Indeed, among ECS phases, the crystalline state and the hexagonal microplateletlike morphology characteristic of ECS-14 seemed favorable properties to obtain continuous and uniform films. ECS-14 phase was used as functional material in screen-printable compositions and was thus deposited by drop coating for morphological, structural, thermal, and electrical characterizations. Possible operation at room temperature was investigated as technological progress, offering intrinsic safety in sensors working in harsh or industrial environments and avoiding high power consumption of most common sensors based on metal oxide semiconductors. Electrical characterization of the sensors based on ECS-14 versus concentrations of gaseous analytes gave significant results at room temperature in the presence of humidity, thereby demonstrating fundamental properties for a good quality sensor (speed, reversibility, and selectivity) that make them competitive with respect to systems currently in use. Remarkably, we observed functionality reversal of the organic and inorganic components; that is, in contrast to other hybrids, for ECS-14 the functional site has been ascribed to the inorganic phase while the organic component provided structural stability to the material. The sensing mechanism for humidity was also investigated.

  9. Time-dependent density functional theory for the charging kinetics of electric double layer containing room-temperature ionic liquids.

    Science.gov (United States)

    Lian, Cheng; Zhao, Shuangliang; Liu, Honglai; Wu, Jianzhong

    2016-11-28

    Understanding the charging kinetics of electric double layers is of fundamental importance for the design and development of novel electrochemical devices such as supercapacitors and field-effect transistors. In this work, we study the dynamic behavior of room-temperature ionic liquids using a classical time-dependent density functional theory that accounts for the molecular excluded volume effects, the electrostatic correlations, and the dispersion forces. While the conventional models predict a monotonic increase of the surface charge with time upon application of an electrode voltage, our results show that dispersion between ions results in a non-monotonic increase of the surface charge with the duration of charging. Furthermore, we investigate the effects of van der Waals attraction between electrode/ionic-liquid interactions on the charging processes.

  10. Selective chloroform sensor using thiol functionalized reduced graphene oxide at room temperature

    Science.gov (United States)

    Midya, Anupam; Mukherjee, Subhrajit; Roy, Shreyasee; Santra, Sumita; Manna, Nilotpal; Ray, Samit K.

    2018-02-01

    This paper presents a highly selective chloroform sensor using functionalised reduced graphene oxide (RGO) as a sensing layer. Thiol group is covalently attached on the basal plan of RGO film by a simple one-step aryl diazonium chemistry to improve its selectivity. Several spectroscopic techniques like X-ray photoelectron, Raman and Fourier transform infrared spectroscopy confirm successful thiol functionalization of RGO. Finally, the fabricated chemiresistor type sensor is exposed to chloroform in the concentration range 200-800 ppm (parts per million). The sensor shows a 4.3% of response towards 800 ppm chloroform. The selectivity of the sensor is analyzed using various volatile organic compounds as well. The devices show enhanced response and faster recovery attributed to the physiosorption of chloroform onto thiol functionalized graphene making them attractive for 2D materials based sensing applications.

  11. A bio-inspired zinc finger analogue anchored in 2D hexagonal meso-porous silica for room temperature CO_2 activation via a hydrogeno-carbonate route

    International Nuclear Information System (INIS)

    Doghri, Hanene; Baranova, Elena A.; Albela, Belen; Bonneviot, Laurent; Mongia Said-Zina

    2017-01-01

    Bio-inspired diethylenetriamine-zinc(II) complexes were anchored into the nano-pores of hexagonal meso-porous MCM41-like silicas targeting a carbamate free and low temperature CO_2 recycling process. A step-by-step approach was adopted to perform an in situ synthesis in order to mimic the zinc finger of carbonic anhydrases, the fastest family of enzymes. In the presence of a surface-masking pattern of TMA"+ ions, some silanol groups were capped using grafted trimethylsilyl functions, TMSgr, (gr for grafted). After removing the masking ions, a tridentate diethylenetriamine ligand was anchored using diethylenetriamine propyl-trimethoxysilane. The so-called DETA_a_n ligands (an for anchored) were partially mono-protonated using either cyclohexane or isopropanol as a solvent. Nonetheless, up to two thirds of them were metallated by Zn(II) ions, leading to the targeted anchored zinc finger mimic [Zn(DETAan)L]+(L = Cl or OH). CO_2 is then adsorbed at room temperature and in humid ambient air by the formation of an intermediate hydrogeno-carbonate-zinc complex. Specific IR signatures at 1330 and 1400 cm"-"1 together with characteristic C 1s and Zn 2p3/2 XPS binding energies at 286.4 and 1024.6 eV advocate for a rather symmetrical bidentate [η"2-CO_3] structural unit in the anchored complex [Zn(DETA_a_n)(η"2-HCO_3"*)]"+, where the Zn(II) ion is most likely penta-coordinated. The internal pH value varied by less than 0.5 depending on the metal reacting with the DETA_a_n ligand and its ability to generate HCO_3"-, due to the buffering effect of surface silanol and amino groups according to the level of protonation of the DETA moieties measured from the N 1s XPS spectra. In contrast to nitrate ions, chloride ions were found to inhibit the formation of hydrogeno-carbonate. (authors)

  12. Room temperature atomic layerlike deposition of ZnS on organic thin films: Role of substrate functional groups and precursors

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhiwei; Walker, Amy V., E-mail: amy.walker@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas, RL10, 800 W. Campbell Rd., Richardson, Texas 75080 (United States)

    2015-09-15

    The room temperature atomic layerlike deposition (ALLD) of ZnS on functionalized self-assembled monolayers (SAMs) was investigated, using diethyl zinc (DEZ) and in situ generated H{sub 2}S as reactants. Depositions on SAMs with three different terminal groups, –CH{sub 3,} –OH, and –COOH, were studied. It was found that the reaction of DEZ with the SAM terminal group is critical in determining the film growth rate. Little or no deposition is observed on –CH{sub 3} terminated SAMs because DEZ does not react with the methyl terminal group. ZnS does deposit on both –OH and –COOH terminated SAMs, but the grow rate on –COOH terminated SAMs is ∼10% lower per cycle than on –OH terminated SAMs. DEZ reacts with the hydroxyl group on –OH terminated SAMs, while on –COOH terminated SAMs it reacts with both the hydroxyl and carbonyl bonds of the terminal groups. The carbonyl reaction is found to lead to the formation of ketones rather than deposition of ZnS, lowering the growth rate on –COOH terminated SAMs. SIMS spectra show that both –OH and –COOH terminated SAMs are covered by the deposited ZnS layer after five ALLD cycles. In contrast to ZnO ALLD where the composition of the film differs for the first few layers on –COOH and –OH terminated SAMs, the deposited film composition is the same for both –COOH and –OH terminated SAMs. The deposited film is found to be Zn-rich, suggesting that the reaction of H{sub 2}S with the Zn-surface adduct may be incomplete.

  13. Highly sensitive work function hydrogen gas sensor based on PdNPs/SiO2/Si structure at room temperature

    Directory of Open Access Journals (Sweden)

    G. Behzadi pour

    Full Text Available In this study, fabrication of highly sensitive PdNPs/SiO2/Si hydrogen gas sensor using experimental and theoretical methods has been investigated. Using chemical method the PdNPs are synthesized and characterized by X-ray diffraction (XRD. The average size of PdNPs is 11 nm. The thickness of the oxide film was 20 nm and the surface of oxide film analyzed using Atomic-force microscopy (AFM. The C-V curve for the PdNPs/SiO2/Si hydrogen gas sensor in 1% hydrogen concentration and at the room temperature has been reported. The response time and recovery time for 1% hydrogen concentration at room temperature were 1.2 s and 10 s respectively. The response (R% for PdNPs/SiO2/Si MOS capacitor hydrogen sensor was 96%. The PdNPs/SiO2/Si MOS capacitor hydrogen sensor showed very fast response and recovery times compared to SWCNTs/PdNPs, graphene/PdNPs, nanorod/PdNPs and nanowire/PdNPs hydrogen gas sensors. Keywords: Sensitive, Oxide film, Capacitive, Resistance

  14. Colossal magnetoresistance in amino-functionalized graphene quantum dots at room temperature: manifestation of weak anti-localization and doorway to spintronics

    Science.gov (United States)

    Roy, Rajarshi; Thapa, Ranjit; Kumar, Gundam Sandeep; Mazumder, Nilesh; Sen, Dipayan; Sinthika, S.; Das, Nirmalya S.; Chattopadhyay, Kalyan K.

    2016-04-01

    In this work, we have demonstrated the signatures of localized surface distortions and disorders in functionalized graphene quantum dots (fGQD) and consequences in magneto-transport under weak field regime (~1 Tesla) at room temperature. Observed positive colossal magnetoresistance (MR) and its suppression is primarily explained by weak anti-localization phenomenon where competitive valley (inter and intra) dependent scattering takes place at room temperature under low magnetic field; analogous to low mobility disordered graphene samples. Furthermore, using ab-initio analysis we show that sub-lattice sensitive spin-polarized ground state exists in the GQD as a result of pz orbital asymmetry in GQD carbon atoms with amino functional groups. This spin polarized ground state is believed to help the weak anti-localization dependent magneto transport by generating more disorder and strain in a GQD lattice under applied magnetic field and lays the premise for future graphene quantum dot based spintronic applications.In this work, we have demonstrated the signatures of localized surface distortions and disorders in functionalized graphene quantum dots (fGQD) and consequences in magneto-transport under weak field regime (~1 Tesla) at room temperature. Observed positive colossal magnetoresistance (MR) and its suppression is primarily explained by weak anti-localization phenomenon where competitive valley (inter and intra) dependent scattering takes place at room temperature under low magnetic field; analogous to low mobility disordered graphene samples. Furthermore, using ab-initio analysis we show that sub-lattice sensitive spin-polarized ground state exists in the GQD as a result of pz orbital asymmetry in GQD carbon atoms with amino functional groups. This spin polarized ground state is believed to help the weak anti-localization dependent magneto transport by generating more disorder and strain in a GQD lattice under applied magnetic field and lays the premise for

  15. Selective detection of SO2 at room temperature based on organoplatinum functionalized single-walled carbon nanotube field effect transistors

    NARCIS (Netherlands)

    Cid, C.C.; Jimenez-Cadena, G.; Riu, J.; Maroto, A.; Rius, F.X.; Batema, G.D.; van Koten, G.

    2009-01-01

    We report a field effect transistor (FET) based on a network of single-walled carbon nanotubes (SWCNTs) that for the first time can selectively detect a single gaseous molecule in air by chemically functionalizing the SWCNTs with a selective molecular receptor. As a target model we used SO2. The

  16. Effect of combination of chitosan coating and irradiation on physicochemical and functional properties of chicken egg during room-temperature storage

    International Nuclear Information System (INIS)

    Liu Xianxe; Jang, Aera; Kim, Dong Hun; Lee, Bong Duk; Lee, Mooha; Jo, Cheorun

    2009-01-01

    The effect of combination of chitosan coating and irradiation on quality and storage stability of shell egg was investigated. Salmonella typhimurium inoculated on eggshell was not detected by irradiation of 2.0 kGy at day 0 and/or chitosan coating (1%, pH 5.0) after 3 days of storage. One-day-old fresh chicken egg was chitosan coated and irradiated at 0, 0.5, 1.0, 1.5 and 2.0 kGy by gamma ray. The egg samples were stored at room temperature for 14 days and the effects of the combination treatment on internal physicochemical and functional properties were investigated. The Haugh unit of egg was decreased by irradiation even at 0.5 kGy. Irradiation increased the lipid oxidation in egg yolk at 2 kGy but the egg with chitosan coating reduced the level of lipid oxidation. Irradiation increased the foaming ability of egg white and decreased viscosity of egg yolk and white. Results suggested that combination of irradiation and chitosan coating can improve safety of shell egg but irradiation treatment may reduce the egg quality for direct consumption. However, an improved functional property for further processing and efficient separation of egg white and yolk can be expected for egg processing industry using irradiation.

  17. Room-Temperature, Ambient-Pressure Chemical Synthesis of Amine-Functionalized Hierarchical Carbon-Sulfur Composites for Lithium-Sulfur Battery Cathodes.

    Science.gov (United States)

    Chae, Changju; Kim, Jinmin; Kim, Ju Young; Ji, Seulgi; Lee, Sun Sook; Kang, Yongku; Choi, Youngmin; Suk, Jungdon; Jeong, Sunho

    2018-02-07

    Recently, the achievement of newly designed carbon-sulfur composite materials has attracted a tremendous amount of attention as high-performance cathode materials for lithium-sulfur batteries. To date, sulfur materials have been generally synthesized by a sublimation technique in sealed containers. This is a well-developed technique for the synthesizing of well-ordered sulfur materials, but it is limited when used to scale up synthetic procedures for practical applications. In this study, we suggest an easily scalable, room-temperature/ambient-pressure chemical pathway for the synthesis of highly functioning cathode materials using electrostatically assembled, amine-terminated carbon materials. It is demonstrated that stable cycling performance outcomes are achievable with a capacity of 730 mAhg -1 at a current density of 1 C with good cycling stability by a virtue of the characteristic chemical/physical properties (a high conductivity for efficient charge conduction and the presence of a number of amine groups that can interact with sulfur atoms during electrochemical reactions) of composite materials. The critical roles of conductive carbon moieties and amine functional groups inside composite materials are clarified with combinatorial analyses by X-ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy.

  18. Room temperature ferromagnetic and photoluminescence ...

    Indian Academy of Sciences (India)

    32

    electrode, photo electronic devices, photo sensors, liquid crystal displays, electrochromic windows, solar panels and transparent coatings for solar-energy heat mirrors [11-13]. Here we report on magnetic properties of ITO nanoparticles at room temperature and at 100 K. 2. Experimental. The In1.9Sn0.1O3 powder samples ...

  19. Novel room temperature ferromagnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Amita [KTH Royal Inst. of Technology, Stockholm (Sweden)

    2004-06-01

    Today's information world, bits of data are processed by semiconductor chips, and stored in the magnetic disk drives. But tomorrow's information technology may see magnetism (spin) and semiconductivity (charge) combined in one 'spintronic' device that exploits both charge and 'spin' to carry data (the best of two worlds). Spintronic devices such as spin valve transistors, spin light emitting diodes, non-volatile memory, logic devices, optical isolators and ultra-fast optical switches are some of the areas of interest for introducing the ferromagnetic properties at room temperature in a semiconductor to make it multifunctional. The potential advantages of such spintronic devices will be higher speed, greater efficiency, and better stability at a reduced power consumption. This Thesis contains two main topics: In-depth understanding of magnetism in Mn doped ZnO, and our search and identification of at least six new above room temperature ferromagnetic semiconductors. Both complex doped ZnO based new materials, as well as a number of nonoxides like phosphides, and sulfides suitably doped with Mn or Cu are shown to give rise to ferromagnetism above room temperature. Some of the highlights of this work are discovery of room temperature ferromagnetism in: (1) ZnO:Mn (paper in Nature Materials, Oct issue, 2003); (2) ZnO doped with Cu (containing no magnetic elements in it); (3) GaP doped with Cu (again containing no magnetic elements in it); (4) Enhancement of Magnetization by Cu co-doping in ZnO:Mn; (5) CdS doped with Mn, and a few others not reported in this thesis. We discuss in detail the first observation of ferromagnetism above room temperature in the form of powder, bulk pellets, in 2-3 mu-m thick transparent pulsed laser deposited films of the Mn (<4 at. percent) doped ZnO. High-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) spectra recorded from 2 to 200nm areas showed homogeneous

  20. A Designed Room Temperature Multilayered Magnetic Semiconductor

    Science.gov (United States)

    Bouma, Dinah Simone; Charilaou, Michalis; Bordel, Catherine; Duchin, Ryan; Barriga, Alexander; Farmer, Adam; Hellman, Frances; Materials Science Division, Lawrence Berkeley National Lab Team

    2015-03-01

    A room temperature magnetic semiconductor has been designed and fabricated by using an epitaxial antiferromagnet (NiO) grown in the (111) orientation, which gives surface uncompensated magnetism for an odd number of planes, layered with the lightly doped semiconductor Al-doped ZnO (AZO). Magnetization and Hall effect measurements of multilayers of NiO and AZO are presented for varying thickness of each. The magnetic properties vary as a function of the number of Ni planes in each NiO layer; an odd number of Ni planes yields on each NiO layer an uncompensated moment which is RKKY-coupled to the moments on adjacent NiO layers via the carriers in the AZO. This RKKY coupling oscillates with the AZO layer thickness, and it disappears entirely in samples where the AZO is replaced with undoped ZnO. The anomalous Hall effect data indicate that the carriers in the AZO are spin-polarized according to the direction of the applied field at both low temperature and room temperature. NiO/AZO multilayers are therefore a promising candidate for spintronic applications demanding a room-temperature semiconductor.

  1. Room temperature cryogenic test interface

    International Nuclear Information System (INIS)

    Faris, S. M.; Davidson, A.; Moskowitz, P. A.; Sai-Halasz, G. A.

    1985-01-01

    This interface permits the testing of high speed semiconductor devices (room-temperature chips) by a Josephson junction sampling device (cryogenic chip) without intolerable loss of resolution. The interface comprises a quartz pass-through plug which includes a planar transmission line interconnecting a first chip station, where the cryogenic chip is mounted, and a second chip station, where the semiconductor chip to be tested is temporarily mounted. The pass-through plug has a cemented long half-cylindrical portion and short half-cylindrical portion. The long portion carries the planar transmission line, the ends of which form the first and second chip mounting stations. The short portion completes the cylinder with the long portion for part of its length, where a seal can be achieved, but does not extend over the chip mounting stations. Sealing is by epoxy cement. The pass-through plug is sealed in place in a flange mounted to the chamber wall. The first chip station, with the cryogenic chip attached, extends into the liquid helium reservoir. The second chip station is in the room temperature environment required for semiconductor operation. Proper semiconductor operating temperature is achieved by a heater wire and control thermocouple in the vicinity of each other and the second chip mounting station. Thermal isolation is maintained by vacuum and seals. Connections for power and control, for test result signals, for temperature control and heating, and for vacuum complete the test apparatus

  2. Room Temperature Ferromagnetic Mn:Ge(001

    Directory of Open Access Journals (Sweden)

    George Adrian Lungu

    2013-12-01

    Full Text Available We report the synthesis of a room temperature ferromagnetic Mn-Ge system obtained by simple deposition of manganese on Ge(001, heated at relatively high temperature (starting with 250 °C. The samples were characterized by low energy electron diffraction (LEED, scanning tunneling microscopy (STM, high resolution transmission electron microscopy (HRTEM, X-ray photoelectron spectroscopy (XPS, superconducting quantum interference device (SQUID, and magneto-optical Kerr effect (MOKE. Samples deposited at relatively elevated temperature (350 °C exhibited the formation of ~5–8 nm diameter Mn5Ge3 and Mn11Ge8 agglomerates by HRTEM, while XPS identified at least two Mn-containing phases: the agglomerates, together with a Ge-rich MnGe~2.5 phase, or manganese diluted into the Ge(001 crystal. LEED revealed the persistence of long range order after a relatively high amount of Mn (100 nm deposited on the single crystal substrate. STM probed the existence of dimer rows on the surface, slightly elongated as compared with Ge–Ge dimers on Ge(001. The films exhibited a clear ferromagnetism at room temperature, opening the possibility of forming a magnetic phase behind a nearly ideally terminated Ge surface, which could find applications in integration of magnetic functionalities on semiconductor bases. SQUID probed the co-existence of a superparamagnetic phase, with one phase which may be attributed to a diluted magnetic semiconductor. The hypothesis that the room temperature ferromagnetic phase might be the one with manganese diluted into the Ge crystal is formulated and discussed.

  3. Impacts of Different Functional Groups on the Kinetic Rates of α-Amine Ketoximesilanes Hydrolysis in the Preparation of Room Temperature Vulcanized Silicone Rubber.

    Science.gov (United States)

    Xu, Huihui; Liu, Zihou; Liu, Qingyang; Bei, Yiling; Zhu, Qingzeng

    2018-05-13

    α-Amine ketoximesilanes are proven to be effective crosslinkers in the preparation of ketone-oxime one-component room temperature vulcanized (RTV) silicone rubber without the use of toxic metal catalyst. This work aimed to investigate the hydrolysis kinetic of α-amine ketoximesilanes, which is vitally important for the preparation of RTV silicone rubber. Five kinds of α-amine ketoximesilanes, namely α-(N,N-diethyl)aminomethyltri(methylethylketoxime)silane (DEMOS), α-(N,N-di-n-butyl)aminomethyltri(methylethylketoxime)silane (DBMOS), α-(N-n-butyl)aminomethyltri(methylethylketoxime)silane (n-BMOS), α-(N-cyclohexyl)aminomethyltri(methylethylketoxime)silane (CMOS) and α-(β-aminomethyl)aminomethyltri(methylethylketoxime)silane (AEMOS), were successfully obtained and confirmed using Fourier transform infrared spectrometer (FT-IR) and hydrogen-1 nuclear magnetic resonance ( ¹H NMR). Kinetics of hydrolysis reactions were measured by FT-IR and conductivity. Our results illustrated that the kinetic constant rates ranged from 12.2 × 10 −4 s −1 to 7.6 × 10 −4 s −1 , with the decreasing order of DEMOS > n-BMOS > DBMOS > CMOS > AEMOS at the given temperature and humidity. Better performances of thermal stability could be achieved when using the α-amine ketoximesilanes as crosslinkers in the preparation of RTV silicon rubber than that of RTV silicone rubber with the use of methyltri(methylethylketoxime)silane (MOS) as a crosslinker and organic tin as a catalyst.

  4. Room temperature PL efficiency of InGaN/GaN quantum well structures with prelayers as a function of number of quantum wells

    International Nuclear Information System (INIS)

    Christian, George M.; Hammersley, Simon; Davies, Matthew J.; Dawson, Philip; Kappers, Menno J.; Massabuau, Fabien C.P.; Oliver, Rachel A.; Humphreys, Colin J.

    2016-01-01

    We report on the effects of varying the number of quantum wells (QWs) in an InGaN/GaN multiple QW (MQW) structure containing a 23 nm thick In0.05Ga0.95N prelayer doped with Si. The calculated conduction and valence bands for the structures show an increasing total electric field across the QWs with increasing number of QWs. This is due to the reduced strength of the surface polarisation field, which opposes the built-in field across the QWs, as its range is increased over thicker samples. Low temperature photoluminescence (PL) measurements show a red shifted QW emission peak energy, which is attributed to the enhanced quantum confined Stark effect with increasing total field strength across the QWs. Low temperature PL time decay measurements and room temperature internal quantum efficiency (IQE) measurements show decreasing radiative recombination rates and decreasing IQE, respectively, with increasing number of QWs. These are attributed to the increased spatial separation of the electron and hole wavefunctions, consistent with the calculated band profiles. It is also shown that, for samples with fewer QWs, the reduction of the total field across the QWs makes the radiative recombination rate sufficiently fast that it is competitive with the efficiency losses associated with the thermal escape of carriers. (copyright 2016 The Authors. Phys. Status Solidi C published by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Microstructure stability of silver electrodeposits at room temperature

    International Nuclear Information System (INIS)

    Hansen, Karsten; Pantleon, Karen

    2008-01-01

    In situ quantitative X-ray diffraction analysis was used to investigate the kinetics of microstructure evolution at room temperature (self-annealing) in an electrodeposited silver layer. As a function of time at room temperature the as-deposited nanocrystalline microstructure evolved considerably: orientation-dependent grain growth and changes of the preferred grain orientation occurred. It is demonstrated for the first time that self-annealing occurs for electrodeposited silver layers and, hence, is not a unique feature of copper as often suggested

  6. Structure of photosystem II and substrate binding at room temperature.

    Science.gov (United States)

    Young, Iris D; Ibrahim, Mohamed; Chatterjee, Ruchira; Gul, Sheraz; Fuller, Franklin; Koroidov, Sergey; Brewster, Aaron S; Tran, Rosalie; Alonso-Mori, Roberto; Kroll, Thomas; Michels-Clark, Tara; Laksmono, Hartawan; Sierra, Raymond G; Stan, Claudiu A; Hussein, Rana; Zhang, Miao; Douthit, Lacey; Kubin, Markus; de Lichtenberg, Casper; Long Vo, Pham; Nilsson, Håkan; Cheah, Mun Hon; Shevela, Dmitriy; Saracini, Claudio; Bean, Mackenzie A; Seuffert, Ina; Sokaras, Dimosthenis; Weng, Tsu-Chien; Pastor, Ernest; Weninger, Clemens; Fransson, Thomas; Lassalle, Louise; Bräuer, Philipp; Aller, Pierre; Docker, Peter T; Andi, Babak; Orville, Allen M; Glownia, James M; Nelson, Silke; Sikorski, Marcin; Zhu, Diling; Hunter, Mark S; Lane, Thomas J; Aquila, Andy; Koglin, Jason E; Robinson, Joseph; Liang, Mengning; Boutet, Sébastien; Lyubimov, Artem Y; Uervirojnangkoorn, Monarin; Moriarty, Nigel W; Liebschner, Dorothee; Afonine, Pavel V; Waterman, David G; Evans, Gwyndaf; Wernet, Philippe; Dobbek, Holger; Weis, William I; Brunger, Axel T; Zwart, Petrus H; Adams, Paul D; Zouni, Athina; Messinger, Johannes; Bergmann, Uwe; Sauter, Nicholas K; Kern, Jan; Yachandra, Vittal K; Yano, Junko

    2016-12-15

    Light-induced oxidation of water by photosystem II (PS II) in plants, algae and cyanobacteria has generated most of the dioxygen in the atmosphere. PS II, a membrane-bound multi-subunit pigment protein complex, couples the one-electron photochemistry at the reaction centre with the four-electron redox chemistry of water oxidation at the Mn 4 CaO 5 cluster in the oxygen-evolving complex (OEC). Under illumination, the OEC cycles through five intermediate S-states (S 0 to S 4 ), in which S 1 is the dark-stable state and S 3 is the last semi-stable state before O-O bond formation and O 2 evolution. A detailed understanding of the O-O bond formation mechanism remains a challenge, and will require elucidation of both the structures of the OEC in the different S-states and the binding of the two substrate waters to the catalytic site. Here we report the use of femtosecond pulses from an X-ray free electron laser (XFEL) to obtain damage-free, room temperature structures of dark-adapted (S 1 ), two-flash illuminated (2F; S 3 -enriched), and ammonia-bound two-flash illuminated (2F-NH 3 ; S 3 -enriched) PS II. Although the recent 1.95 Å resolution structure of PS II at cryogenic temperature using an XFEL provided a damage-free view of the S 1 state, measurements at room temperature are required to study the structural landscape of proteins under functional conditions, and also for in situ advancement of the S-states. To investigate the water-binding site(s), ammonia, a water analogue, has been used as a marker, as it binds to the Mn 4 CaO 5 cluster in the S 2 and S 3 states. Since the ammonia-bound OEC is active, the ammonia-binding Mn site is not a substrate water site. This approach, together with a comparison of the native dark and 2F states, is used to discriminate between proposed O-O bond formation mechanisms.

  7. Room temperature creep in metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Deibler, Lisa Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Materials Characterization and Performance

    2014-09-01

    Time dependent deformation in the form of creep and stress relaxation is not often considered a factor when designing structural alloy parts for use at room temperature. However, creep and stress relaxation do occur at room temperature (0.09-0.21 Tm for alloys in this report) in structural alloys. This report will summarize the available literature on room temperature creep, present creep data collected on various structural alloys, and finally compare the acquired data to equations used in the literature to model creep behavior. Based on evidence from the literature and fitting of various equations, the mechanism which causes room temperature creep is found to include dislocation generation as well as exhaustion.

  8. IMPROVED SYNTHESIS OF ROOM TEMPERATURE IONIC LIQUIDS

    Science.gov (United States)

    Room temperature ionic liquids (RTILs), molten salts comprised of N-alkylimidazolium cations and various anions, have received significant attention due to their commercial potential in a variety of chemical applications especially as substitutes for conventional volatile organic...

  9. Room temperature synthesis of biodiesel using sulfonated ...

    Science.gov (United States)

    Sulfonation of graphitic carbon nitride (g-CN) affords a polar and strongly acidic catalyst, Sg-CN, which displays unprecedented reactivity and selectivity in biodiesel synthesis and esterification reactions at room temperature. Prepared for submission to Royal Society of Chemistry (RSC) journal, Green Chemistry as a communication.

  10. Water in Room Temperature Ionic Liquids

    Science.gov (United States)

    Fayer, Michael

    2014-03-01

    Room temperature ionic liquids (or RTILs, salts with a melting point below 25 °C) have become a subject of intense study over the last several decades. Currently, RTIL application research includes synthesis, batteries, solar cells, crystallization, drug delivery, and optics. RTILs are often composed of an inorganic anion paired with an asymmetric organic cation which contains one or more pendant alkyl chains. The asymmetry of the cation frustrates crystallization, causing the salt's melting point to drop significantly. In general, RTILs are very hygroscopic, and therefore, it is of interest to examine the influence of water on RTIL structure and dynamics. In addition, in contrast to normal aqueous salt solutions, which crystallize at low water concentration, in an RTIL it is possible to examine isolated water molecules interacting with ions but not with other water molecules. Here, optical heterodyne-detected optical Kerr effect (OHD-OKE) measurements of orientational relaxation on a series of 1-alkyl-3-methylimidazolium tetrafluoroborate RTILs as a function of chain length and water concentration are presented. The addition of water to the longer alkyl chain RTILs causes the emergence of a long time bi-exponential orientational anisotropy decay. Such decays have not been seen previously in OHD-OKE experiments on any type of liquid and are analyzed here using a wobbling-in-a-cone model. The orientational relaxation is not hydrodynamic, with the slowest relaxation component becoming slower as the viscosity decreases for the longest chain, highest water content samples. The dynamics of isolated D2O molecules in 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6) were examined using two dimensional infrared (2D IR) vibrational echo spectroscopy. Spectral diffusion and incoherent and coherent transfer of excitation between the symmetric and antisymmetric modes are examined. The coherent transfer experiments are used to address the nature of inhomogeneous

  11. Room temperature CO and H2 sensing with carbon nanoparticles

    International Nuclear Information System (INIS)

    Kim, Daegyu; Pikhitsa, Peter V; Yang, Hongjoo; Choi, Mansoo

    2011-01-01

    We report on a shell-shaped carbon nanoparticle (SCNP)-based gas sensor that reversibly detects reducing gas molecules such as CO and H 2 at room temperature both in air and inert atmosphere. Crystalline SCNPs were synthesized by laser-assisted reactions in pure acetylene gas flow, chemically treated to obtain well-dispersed SCNPs and then patterned on a substrate by the ion-induced focusing method. Our chemically functionalized SCNP-based gas sensor works for low concentrations of CO and H 2 at room temperature even without Pd or Pt catalysts commonly used for splitting H 2 molecules into reactive H atoms, while metal oxide gas sensors and bare carbon-nanotube-based gas sensors for sensing CO and H 2 molecules can operate only at elevated temperatures. A pristine SCNP-based gas sensor was also examined to prove the role of functional groups formed on the surface of functionalized SCNPs. A pristine SCNP gas sensor showed no response to reducing gases at room temperature but a significant response at elevated temperature, indicating a different sensing mechanism from a chemically functionalized SCNP sensor.

  12. Room-temperature ductile inorganic semiconductor

    Science.gov (United States)

    Shi, Xun; Chen, Hongyi; Hao, Feng; Liu, Ruiheng; Wang, Tuo; Qiu, Pengfei; Burkhardt, Ulrich; Grin, Yuri; Chen, Lidong

    2018-05-01

    Ductility is common in metals and metal-based alloys, but is rarely observed in inorganic semiconductors and ceramic insulators. In particular, room-temperature ductile inorganic semiconductors were not known until now. Here, we report an inorganic α-Ag2S semiconductor that exhibits extraordinary metal-like ductility with high plastic deformation strains at room temperature. Analysis of the chemical bonding reveals systems of planes with relatively weak atomic interactions in the crystal structure. In combination with irregularly distributed silver-silver and sulfur-silver bonds due to the silver diffusion, they suppress the cleavage of the material, and thus result in unprecedented ductility. This work opens up the possibility of searching for ductile inorganic semiconductors/ceramics for flexible electronic devices.

  13. Electrically Injected Twin Photon Emitting Lasers at Room Temperature

    Directory of Open Access Journals (Sweden)

    Claire Autebert

    2016-08-01

    Full Text Available On-chip generation, manipulation and detection of nonclassical states of light are some of the major issues for quantum information technologies. In this context, the maturity and versatility of semiconductor platforms are important assets towards the realization of ultra-compact devices. In this paper we present our work on the design and study of an electrically injected AlGaAs photon pair source working at room temperature. The device is characterized through its performances as a function of temperature and injected current. Finally we discuss the impact of the device’s properties on the generated quantum state. These results are very promising for the demonstration of electrically injected entangled photon sources at room temperature and let us envision the use of III-V semiconductors for a widespread diffusion of quantum communication technologies.

  14. Thermal power generation during heat cycle near room temperature

    Science.gov (United States)

    Shibata, Takayuki; Fukuzumi, Yuya; Kobayashi, Wataru; Moritomo, Yutaka

    2018-01-01

    We demonstrate that a sodium-ion secondary battery (SIB)-type thermocell consisting of two types of Prussian blue analogue (PBA) with different electrochemical thermoelectric coefficients (S EC ≡ ∂V/∂T V and T are the redox potential and temperature, respectively) produces electrical energy during heat cycles. The device produces an electrical energy of 2.3 meV/PBA per heat cycle between 295 K (= T L) and 323 K (= T H). The ideal thermal efficiency (η = 1.0%), which is evaluated using the heat capacity (C = 4.16 meV/K) of ideal Na2Co[Fe(CN)6], reaches 11% of the Carnot efficiency (ηth = 8.7%). Our SIB-type thermocell is a promising thermoelectric device that harvests waste heat near room temperature.

  15. A Promising New Method to Estimate Drug-Polymer Solubility at Room Temperature

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Gannon, Natasha; Porsch, Ilona

    2016-01-01

    The established methods to predict drug-polymer solubility at room temperature either rely on extrapolation over a long temperature range or are limited by the availability of a liquid analogue of the polymer. To overcome these issues, this work investigated a new methodology where the drug-polymer...... solubility is estimated from the solubility of the drug in a solution of the polymer at room temperature using the shake-flask method. Thus, the new polymer in solution method does not rely on temperature extrapolations and only requires the polymer and a solvent, in which the polymer is soluble, that does...... not affect the molecular structure of the drug and polymer relative to that in the solid state. Consequently, as this method has the potential to provide fast and precise estimates of drug-polymer solubility at room temperature, we encourage the scientific community to further investigate this principle both...

  16. Materials for room temperature magnetic refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Rosendahl Hansen, B.

    2010-07-15

    Magnetic refrigeration is a cooling method, which holds the promise of being cleaner and more efficient than conventional vapor-compression cooling. Much research has been done during the last two decades on various magnetic materials for this purpose and today a number of materials are considered candidates as they fulfill many of the requirements for a magnetic refrigerant. However, no one material stands out and the field is still active with improving the known materials and in the search for a better one. Magnetic cooling is based on the magnetocaloric effect, which causes a magnetic material to change its temperature when a magnetic field is applied or removed. For room temperature cooling, one utilizes that the magnetocaloric effect peaks near magnetic phase transitions and so the materials of interest all have a critical temperature within the range of 250 - 310 K. A magnetic refrigerant should fulfill a number of criteria, among these a large magnetic entropy change, a large adiabatic temperature change, preferably little to no thermal or magnetic hysteresis and the material should have the stability required for long term use. As the temperature range required for room temperature cooling is some 40 - 50 K, the magnetic refrigerant should also be able to cover this temperature span either by exhibiting a very broad peak in magnetocaloric effect or by providing the opportunity for creating a materials series with varying transition temperatures. (Author)

  17. Room temperature isotherms for Mo and Ni

    International Nuclear Information System (INIS)

    Masse, J.L.

    1986-11-01

    Isotherms at room temperature for Mo and Ni are proposed. They are of three types: BIRCH, KEANE and BORN-MIE. The adjustable constants appearing in these isotherms have been determined from experimental quantities at zero pressure. An evaluation of the limit of (δB T /δP) T as P #-> # ∞, where B T is the isothermal bulk modulus, has been also used. These three isotherms obtained for Mo and Ni are compared with isotherms derived from shock-wave data according to the PRIETO's model. There is a good agreement between these and these derived from shock-wave data. The three isotherms proposed for Mo and Ni can be considered as valid until pressures of several B To , where B To is the bulk modulus B T at P = o [fr

  18. Magnetic heat pumping near room temperature

    Science.gov (United States)

    Brown, G. V.

    1976-01-01

    It is shown that magnetic heat pumping can be made practical at room temperature by using a ferromagnetic material with a Curie point at or near operating temperature and an appropriate regenerative thermodynamic cycle. Measurements are performed which show that gadolinium is a resonable working material and it is found that the application of a 7-T magnetic field to gadolinium at the Curie point (293 K) causes a heat release of 4 kJ/kg under isothermal conditions or a temperature rise of 14 K under adiabatic conditions. A regeneration technique can be used to lift the load of the lattice and electronic heat capacities off the magnetic system in order to span a reasonable temperature difference and to pump as much entropy per cycle as possible

  19. Magnetocaloric refrigeration near room temperature (invited)

    International Nuclear Information System (INIS)

    Brueck, E.; Tegus, O.; Thanh, D.T.C.; Buschow, K.H.J.

    2007-01-01

    Modern society relies on readily available refrigeration. The ideal cooling machine would be a compact, solid state, silent and energy-efficient heat pump that does not require maintenance. Magnetic refrigeration has three prominent advantages compared to compressor-based refrigeration. First, there are no harmful gases involved, second it may be built more compact as the working material is a solid and third magnetic refrigerators generate much less noise. Recently, a new class of magnetic refrigerant materials for room-temperature applications was discovered. These new materials have important advantages over existing magnetic coolants: They exhibit a large magnetocaloric effect (MCE) in conjunction with a magnetic phase transition of first order. This MCE is, larger than that of Gd metal, which is used in the demonstration refrigerators built to explore the potential of this evolving technology. In the present review, we compare the different materials considering both scientific aspects and industrial applicability

  20. Materials for Room Temperature Magnetic Refrigeration

    DEFF Research Database (Denmark)

    Hansen, Britt Rosendahl

    Magnetic refrigeration is a cooling method, which holds the promise of being cleaner and more efficient than conventional vapor-compression cooling. Much research has been done during the last two decades on various magnetic materials for this purpose and today a number of materials are considered...... candidates as they fulfill many of the requirements for a magnetic refrigerant. However, no one material stands out and the field is still active with improving the known materials and in the search for a better one. Magnetic cooling is based on the magnetocaloric effect, which causes a magnetic material...... to change its temperature when a magnetic field is applied or removed. For room temperature cooling, one utilizes that the magnetocaloric effect peaks near magnetic phase transitions and so the materials of interest all have a critical temperature within the range of 250 – 310 K. A magnetic refrigerant...

  1. Above Room Temperature Lead Salt VECSELs

    Science.gov (United States)

    Rahim, M.; Khiar, A.; Felder, F.; Fill, M.; Chappuis, D.; Zogg, H.

    2010-01-01

    Mid-infrared vertical external cavity surface emitting lasers (VECSEL) were developed for the wavelength range 4 to 5 μm. The devices are based on lead salt materials grown by MBE on BaF2 or Si substrate. The VECSELs are optically pumped with a 1.55 μm wavelength laser. They are operating up to above room temperature. An output power 6 mWp was reached at a temperature of +27°C. The VECSELs are temperature tunable and lasing is observed from ˜4.8 μm at -60°C down to ˜4.2 μm at +40°C heat sink temperature.

  2. Electrorecovery of actinides at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, Michael E [Los Alamos National Laboratory; Oldham, Warren J [Los Alamos National Laboratory; Costa, David A [Los Alamos National Laboratory

    2008-01-01

    There are a large number of purification and processing operations involving actinide species that rely on high-temperature molten salts as the solvent medium. One such application is the electrorefining of impure actinide metals to provide high purity material for subsequent applications. There are some drawbacks to the electrodeposition of actinides in molten salts including relatively low yields, lack of accurate potential control, maintaining efficiency in a highly corrosive environment, and failed runs. With these issues in mind we have been investigating the electrodeposition of actinide metals, mainly uranium, from room temperature ionic liquids (RTILs) and relatively high-boiling organic solvents. The RTILs we have focused on are comprised of 1,3-dialkylimidazolium or quaternary ammonium cations and mainly the {sup -}N(SO{sub 2}CF{sub 3}){sub 2} anion [bis(trif1uoromethylsulfonyl)imide {equivalent_to} {sup -}NTf{sub 2}]. These materials represent a class of solvents that possess great potential for use in applications employing electrochemical procedures. In order to ascertain the feasibility of using RTILs for bulk electrodeposition of actinide metals our research team has been exploring the electron transfer behavior of simple coordination complexes of uranium dissolved in the RTIL solutions. More recently we have begun some fundamental electrochemical studies on the behavior of uranium and plutonium complexes in the organic solvents N-methylpyrrolidone (NMP) and dimethylsulfoxide (DMSO). Our most recent results concerning electrodeposition will be presented in this account. The electrochemical behavior of U(IV) and U(III) species in RTILs and the relatively low vapor pressure solvents NMP and DMSO is described. These studies have been ongoing in our laboratory to uncover conditions that will lead to the successful bulk electrodeposition of actinide metals at a working electrode surface at room temperature or slightly elevated temperatures. The RTILs we

  3. Titanium nitride room-temperature ferromagnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, Iu.G., E-mail: morozov@ism.ac.ru [Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, 8 Academician Osipyan Street, Chernogolovka, Moscow Region, 142432 (Russian Federation); Belousova, O.V. [Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, 8 Academician Osipyan Street, Chernogolovka, Moscow Region, 142432 (Russian Federation); Belyakov, O.A. [Ogarev Mordovia State University, Saransk, 68 Bol' shevistskaya Street, 430005 (Russian Federation); Parkin, I.P., E-mail: i.p.parkin@ucl.ac.uk [Department of Chemistry, Materials Chemistry Research Centre, University College London, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Sathasivam, S. [Department of Chemistry, Materials Chemistry Research Centre, University College London, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Kuznetcov, M.V., E-mail: maxim1968@mail.ru [All-Russian Research Institute on Problems of Civil Defense and Emergencies of Emergency Control Ministry of Russia (EMERCOM), 7 Davidkovskaya Street, Moscow, 121352 (Russian Federation)

    2016-08-05

    Cubic and near-spherical TiN nanoparticles ranging in average size from 20 to 125 nm were prepared by levitation-jet aerosol synthesis through condensation of titanium vapor in an inert gas flow with gaseous nitrogen injection. The nanoparticles were characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET measurements, UV–Vis, FT-IR, Raman spectroscopy, XPS, and vibrating-sample magnetometry. Room-temperature ferromagnetism with maximum magnetization up to 2.5 emu/g was recorded for the nanoparticles. The results indicate that the observed ferromagnetic ordering was related to the defect Ti–N structures on the surface of nanoparticles. This suggestion is in good correlation with the measured spectroscopical data. - Highlights: • Levitation-jet aerosol synthesis of TiN nanoparticles (NPs). • SEM, XRD, BET, UV–vis, FT-IR, Raman, XPS and magnetic characterization of the NPs. • Correlation between optical and XPS measurements data and maximum magnetization of the NPs.

  4. Dual-function radiation sensitizers and bioreductive drugs: factors affecting cellular uptake and sensitizing efficiency in analogues of RSU 1069

    International Nuclear Information System (INIS)

    Walling, J.; Stratford, I.J.; Adams, G.E.; Stephens, M.A.

    1988-01-01

    Alkyl aziridine analogues of the hypoxic cell radiosensitizer RSU 1069 have been synthesized and one, RB 7040, containing tetramethyl substituted aziridine, is a more efficient sensitizer in vitro than RSU 1069 (Ahmed et al., 1986). The extent to which variation in drug uptake can influence the sensitizing efficiency of RSU 1069 and its analogues has been investigated by determining cellular uptake as a function of pH of extracellular medium (pHsub(e)) over the range 5.4-8.4. Following exposure of V79 cells for 1 h at room temperature, the ratio of intra-to extracellular concentration (Ci/Ce) was near unity at pH 5.4. Increasing pHsub(e) to 8.4 resulted in no change in the ratio Ci/Ce for RSU 1069 (pKsub(a) = 6.04). Values of Ci/Ce increased three-fold for RSU 1165 (pKsub(a) 7.38) and eleven-fold for RB 7040 (pKsub(a) = 8.45). Radiosensitization by RSU 1069 showed little dependence on pHsub(e) whereas increasing pH caused an apparent increase in sensitizing efficiency of both RSU 1165 and RB 7040. When enhancement ratios for sensitization were normalized to take account of the effect of extracellular pH on drug uptake, efficiency of sensitization was independent of pHsub(e). (author)

  5. Energy-filtered cold electron transport at room temperature.

    Science.gov (United States)

    Bhadrachalam, Pradeep; Subramanian, Ramkumar; Ray, Vishva; Ma, Liang-Chieh; Wang, Weichao; Kim, Jiyoung; Cho, Kyeongjae; Koh, Seong Jin

    2014-09-10

    Fermi-Dirac electron thermal excitation is an intrinsic phenomenon that limits functionality of various electron systems. Efforts to manipulate electron thermal excitation have been successful when the entire system is cooled to cryogenic temperatures, typically distribution corresponds to an effective electron temperature of ~45 K, can be transported throughout device components without external cooling. This is accomplished using a discrete level of a quantum well, which filters out thermally excited electrons and permits only energy-suppressed electrons to participate in electron transport. The quantum well (~2 nm of Cr2O3) is formed between source (Cr) and tunnelling barrier (SiO2) in a double-barrier-tunnelling-junction structure having a quantum dot as the central island. Cold electron transport is detected from extremely narrow differential conductance peaks in electron tunnelling through CdSe quantum dots, with full widths at half maximum of only ~15 mV at room temperature.

  6. Thermal investigations of a room temperature magnetic refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Smaili, Arezki; Chiba, Younes [Ecole Nationale Polytechnique d' Alger (Algeria)], email: arezki.smaili@enp.edu.dz

    2011-07-01

    Magnetic refrigeration is a concept based on the magnetocaloric effect that some materials exhibit when the external magnetic field changes. The aim of this paper is to assess the performance of a numerical model in predicting parameters of an active magnetic regenerator refrigerator. Numerical simulations were conducted to perform a thermal analysis on an active magnetic regenerator refrigerator operating near room temperature with and without applied cooling load. Curves of temperature span, cooling capacity and thermal efficiency as functions of the operating conditions were drawn and are presented in this paper. Results showed that at fixed frequency Ql versus mf has an optimum and COP was increased with cycle frequency values. This study demonstrated that the proposed numerical model could be used to predict parameters of an active magnetic regenerator refrigerator as it provides consistent results.

  7. Electromagnon Resonance at Room Temperature with Gigantic Magnetochromism

    Science.gov (United States)

    Shishikura, H.; Tokunaga, Y.; Takahashi, Y.; Masuda, R.; Taguchi, Y.; Kaneko, Y.; Tokura, Y.

    2018-04-01

    The elementary excitation characteristic of magnetoelectric (ME) multiferroics is a magnon endowed with electric activity, which is referred to as an electromagnon. The electromagnon resonance mediated by the bilinear exchange coupling potentially exhibits strong terahertz light-matter interaction with optical properties different from the conventional magnon excitation. Here we report the robust electromagnon resonance on helimagnetic Y -type hexaferrites in a wide temperature range including room temperature. Furthermore, the efficient magnetic field controls of the electromagnon are demonstrated on the flexible spin structure of these compounds, leading to the generation or annihilation of the resonance as well as the large resonance energy shift. These terahertz characteristics of the electromagnon exemplify the versatile magneto-optical functionality driven by the ME coupling in multiferroics, paving a way for possible terahertz applications as well as terahertz control of a magnetic state of matter.

  8. Evolution of the microstructure in nanocrystalline copper electrodeposits during room temperature storage

    DEFF Research Database (Denmark)

    Pantleon, Karen; Somers, Marcel A. J.

    2007-01-01

    The microstructure evolution in copper electrodeposits at room temperature (self-annealing) was investigated by means of X-ray diffraction analysis and simultaneous measurement of the electrical resistivity as a function of time. In-situ studies were started immediately after electrodeposition......, crystallographic texture changes by multiple twinning and a decrease of the electrical resistivity occurred as a function of time at room temperature. The kinetics of self-annealing is strongly affected by the layer thickness: the thinner the layer the slower is the microstructure evolution and self-annealing...

  9. Room Temperature Silicene Field-Effect Transistors

    Science.gov (United States)

    Akinwande, Deji

    Silicene, a buckled Si analogue of graphene, holds significant promise for future electronics beyond traditional CMOS. In our predefined experiments via encapsulated delamination with native electrodes approach, silicene devices exhibit an ambipolar charge transport behavior, corroborating theories on Dirac band in Ag-free silicene. Monolayer silicene device has extracted field-effect mobility within the theoretical expectation and ON/OFF ratio greater than monolayer graphene, while multilayer silicene devices show decreased mobility and gate modulation. Air-stability of silicene devices depends on the number of layers of silicene and intrinsic material structure determined by growth temperature. Few or multi-layer silicene devices maintain their ambipolar behavior for days in contrast to minutes time scale for monolayer counterparts under similar conditions. Multilayer silicene grown at different temperatures below 300oC possess different intrinsic structures and yield different electrical property and air-stability. This work suggests a practical prospect to enable more air-stable silicene devices with layer and growth condition control, which can be leveraged for other air-sensitive 2D materials. In addition, we describe quantum and classical transistor device concepts based on silicene and related buckled materials that exploit the 2D topological insulating phenomenon. The transistor device physics offer the potential for ballistic transport that is robust against scattering and can be employed for both charge and spin transport. This work was supported by the ARO.

  10. Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite

    KAUST Repository

    Lin, Aigu L.; Rodrigues, J. N B; Su, Chenliang; Milletari, M.; Loh, Kian Ping; Wu, Tao; Chen, Wei; Neto, A. H Castro; Adam, Shaffique; Wee, Andrew T S

    2015-01-01

    Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an iron-oxide and graphene oxide nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m2/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite. © 2015 Scientific Reports.

  11. Room-temperature ferromagnetism observed in C-/N-/O-implanted MgO single crystals

    Science.gov (United States)

    Li, Qiang; Ye, Bonian; Hao, Yingping; Liu, Jiandang; Zhang, Jie; Zhang, Lijuan; Kong, Wei; Weng, Huimin; Ye, Bangjiao

    2013-01-01

    MgO single crystals were implanted with 70 keV C/N/O ions at room temperature with respective doses of 2 × 1016 and 2 × 1017 ions/cm2. All samples with high-dose implantation showed room temperature hysteresis in magnetization loops. Magnetization and slow positron annihilation measurements confirmed that room temperature ferromagnetism in O-implanted samples was attributed to the presence of Mg vacancies. Furthermore, the introduction of C or N played more effective role in ferromagnetic performance than Mg vacancies. Moreover, the magnetic moment possibly occurred from the localized wave function of unpaired electrons and the exchange interaction formed a long-range magnetic order.

  12. Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite

    KAUST Repository

    Lin, Aigu L.

    2015-06-23

    Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an iron-oxide and graphene oxide nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m2/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite. © 2015 Scientific Reports.

  13. Evolution of the microstructure in electrochemically deposited copper films at room temperature

    DEFF Research Database (Denmark)

    Pantleon, Karen; Somers, Marcel A. J.

    2007-01-01

    The room temperature evolution of the microstructure in copper electrodeposits (self-annealing) was investigated by means of X-ray diffraction analysis and simultaneous measurement of the electrical resistivity as a function of time with an unprecedented time resolution. Independent of the copper...... the crystallographic texture changes by a multiple twinning mechanism. The kinetics of self-annealing is strongly affected by the thickness of the deposit. Storage of the copper films at sub-zero temperatures effectively hinders self-annealing and does not affect the kinetics of self-annealing upon reheating to room...... temperature....

  14. Exploiting fast detectors to enter a new dimension in room-temperature crystallography

    International Nuclear Information System (INIS)

    Owen, Robin L.; Paterson, Neil; Axford, Danny; Aishima, Jun; Schulze-Briese, Clemens; Ren, Jingshan; Fry, Elizabeth E.; Stuart, David I.; Evans, Gwyndaf

    2014-01-01

    A departure from a linear or an exponential decay in the diffracting power of macromolecular crystals is observed and accounted for through consideration of a multi-state sequential model. A departure from a linear or an exponential intensity decay in the diffracting power of protein crystals as a function of absorbed dose is reported. The observation of a lag phase raises the possibility of collecting significantly more data from crystals held at room temperature before an intolerable intensity decay is reached. A simple model accounting for the form of the intensity decay is reintroduced and is applied for the first time to high frame-rate room-temperature data collection

  15. Room Temperature Ultralow Threshold GaN Nanowire Polariton Laser

    KAUST Repository

    Das, Ayan; Heo, Junseok; Jankowski, Marc; Guo, Wei; Zhang, Lei; Deng, Hui; Bhattacharya, Pallab

    2011-01-01

    , and 2 orders of magnitude lower than any existing room-temperature polariton devices. Spectral, polarization, and coherence properties of the emission were measured to confirm polariton lasing. © 2011 American Physical Society.

  16. High Power Room Temperature Terahertz Local Oscillator, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to build a high-power, room temperature compact continuous wave terahertz local oscillator for driving heterodyne receivers in the 1-5 THz frequency...

  17. Neutron absorbing room temperature vulcanizable silicone rubber compositions

    International Nuclear Information System (INIS)

    Zoch, H.L.

    1979-01-01

    A neutron absorbing composition is described and consists of a one-component room temperature vulcanizable silicone rubber composition or a two-component room temperature vulcanizable silicone rubber composition in which the composition contains from 25 to 300 parts by weight based on the base silanol or vinyl containing diorganopolysiloxane polymer of a boron compound or boron powder as the neutron absorbing ingredient. An especially useful boron compound in this application is boron carbide. 20 claims

  18. Room temperature Compton profiles of conduction electrons in α-Ga ...

    Indian Academy of Sciences (India)

    Room temperature Compton profiles of momentum distribution of conduction electrons in -Ga metal are calculated in band model. For this purpose, the conduction electron wave functions are determined in a temperature-dependent non-local model potential. The profiles calculated along the crystallographic directions, ...

  19. Room-temperature base-free copper-catalyzed trifluoromethylation of organotrifluoroborates to trifluoromethylarenes

    KAUST Repository

    Huang, Yuanyuan; Fang, Xin; Lin, Xiaoxi; Li, Huaifeng; He, Weiming; Huang, Kuo-Wei; Yuan, Yaofeng; Weng, Zhiqiang

    2012-01-01

    An efficient room temperature copper-catalyzed trifluoromethylation of organotrifluoroborates under the base free condition using an electrophilic trifluoromethylating reagent is demonstrated. The corresponding trifluoromethylarenes were obtained in good to excellent yields and the reaction tolerates a wide range of functional groups. © 2012 Elsevier Ltd. All rights reserved.

  20. Room-temperature base-free copper-catalyzed trifluoromethylation of organotrifluoroborates to trifluoromethylarenes

    KAUST Repository

    Huang, Yuanyuan

    2012-12-01

    An efficient room temperature copper-catalyzed trifluoromethylation of organotrifluoroborates under the base free condition using an electrophilic trifluoromethylating reagent is demonstrated. The corresponding trifluoromethylarenes were obtained in good to excellent yields and the reaction tolerates a wide range of functional groups. © 2012 Elsevier Ltd. All rights reserved.

  1. Room temperature triplet state spectroscopy of organic semiconductors.

    Science.gov (United States)

    Reineke, Sebastian; Baldo, Marc A

    2014-01-21

    Organic light-emitting devices and solar cells are devices that create, manipulate, and convert excited states in organic semiconductors. It is crucial to characterize these excited states, or excitons, to optimize device performance in applications like displays and solar energy harvesting. This is complicated if the excited state is a triplet because the electronic transition is 'dark' with a vanishing oscillator strength. As a consequence, triplet state spectroscopy must usually be performed at cryogenic temperatures to reduce competition from non-radiative rates. Here, we control non-radiative rates by engineering a solid-state host matrix containing the target molecule, allowing the observation of phosphorescence at room temperature and alleviating constraints of cryogenic experiments. We test these techniques on a wide range of materials with functionalities spanning multi-exciton generation (singlet exciton fission), organic light emitting device host materials, and thermally activated delayed fluorescence type emitters. Control of non-radiative modes in the matrix surrounding a target molecule may also have broader applications in light-emitting and photovoltaic devices.

  2. Room Temperature Memory for Few Photon Polarization Qubits

    Science.gov (United States)

    Kupchak, Connor; Mittiga, Thomas; Jordan, Bertus; Nazami, Mehdi; Nolleke, Christian; Figueroa, Eden

    2014-05-01

    We have developed a room temperature quantum memory device based on Electromagnetically Induced Transparency capable of reliably storing and retrieving polarization qubits on the few photon level. Our system is realized in a vapor of 87Rb atoms utilizing a Λ-type energy level scheme. We create a dual-rail storage scheme mediated by an intense control field to allow storage and retrieval of any arbitrary polarization state. Upon retrieval, we employ a filtering system to sufficiently remove the strong pump field, and subject retrieved light states to polarization tomography. To date, our system has produced signal-to-noise ratios near unity with a memory fidelity of >80 % using coherent state qubits containing four photons on average. Our results thus demonstrate the feasibility of room temperature systems for the storage of single-photon-level photonic qubits. Such room temperature systems will be attractive for future long distance quantum communication schemes.

  3. Spin dynamics in bulk CdTe at room temperature

    International Nuclear Information System (INIS)

    Nahalkova, P.; Nemec, P.; Sprinzl, D.; Belas, E.; Horodysky, P.; Franc, J.; Hlidek, P.; Maly, P.

    2006-01-01

    In this paper, we report on the room temperature dynamics of spin-polarized carriers in undoped bulk CdTe. Platelets of CdTe with different concentration of preparation-induced dislocations were prepared by combining the mechanical polishing and chemical etching. Using the polarization-resolved pump-probe experiment in transmission geometry, we have observed a systematic decrease of both the signal polarization and the electron spin dephasing time (from 52 to 36 ps) with the increased concentration of defects. We have suggested that the Elliot-Yafet mechanism might be the dominant spin dephasing mechanism in platelets of CdTe at room temperature

  4. Dynamics and Interactions in Room Temperature Ionic Liquids, Surfaces and Interfaces

    Science.gov (United States)

    2016-01-13

    OHD-OKE) experiments. The first 2D IR experiments on functionalized SiO2 planar surface monolayers of alkyl chains with a vibrational probe head group...alkyl groups lowers the temperature for crystallization below room temperature and can also result in supercooling and glass formation rather than...heterodyne detected optical Kerr effect (OHD-OKE) experiments. During the grant, we performed the first 2D IR experiments on functionalized SiO2

  5. Experimental study on the double barrier structure at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, H Y; Chua, S J [Centre for Optoelectronics, Dept. of Electrical Engineering, National Univ. of Singapore (Singapore)

    1994-06-15

    An experimental study of AlAs / GaAs / AlAs double barrier structure is carried out. The double barrier and quantum well structure are grown by MBE. The peak-to-valley ratio 2.6 : 1 with peak current density of 1.6 kA/cm/sup 2 at room temperature have been achieved. (authors)

  6. Gold catalysed synthesis of 3-alkoxyfurans at room temperature.

    Science.gov (United States)

    Pennell, Matthew N; Foster, Robert W; Turner, Peter G; Hailes, Helen C; Tame, Christopher J; Sheppard, Tom D

    2014-02-09

    Synthetically important 3-alkoxyfurans can be prepared efficiently via treatment of acetal-containing propargylic alcohols (obtained from the addition of 3,3-diethoxypropyne to aldehydes) with 2 mol% gold catalyst in an alcohol solvent at room temperature. The resulting furans show useful reactivity in a variety of subsequent transformations.

  7. Enhanced room temperature multiferroicity in Gd doped BFO

    CSIR Research Space (South Africa)

    Pradhan, SK

    2009-01-01

    Full Text Available deficient Gd doped multiferroic BFO system. At particular doping level of Gd, this bulk ceramics showed spectacular M~H behavior at room temperature which is likely to open a new avenue for the potential applications in information storing technology as well...

  8. Exchange of hydrogen isotopes in oxide ceramics at room temperature

    International Nuclear Information System (INIS)

    Suzuki, H.; Morita, K.; Soda, K.

    2001-01-01

    The decay curves of D and up-take curves of H on the exchange of D implanted into Li 2 TiO 3 for H in H 2 O vapor caused by exposure to normal-air at room temperature have been measured as a function of exposure time at different implantation concentrations by means of the elastic recoil detection technique. The re-emission curves of D retained and H up-taken in a specimen by isochronal annealing for 10 min have been also measured. It is found that the thermal re-emission of D and H takes place uniformly over the whole specimen due to local molecular recombination in the bulk and that the re-emission rates of H and D in the near-surface layers are slower than those in the deeper layers. It is also found that the decay of D caused by the D-H exchange takes place rapidly in the beginning and the retained amount of D attains at a constant level and the retained fraction of D are higher as the initial implantation concentrations of D are lower. The decay curves of D and the up-take curves of H have been analysed using the mass balance equations, in which the elementary processes are taken into account according to the exchange model of one way diffusion from the surface into the bulk. It is shown that the solution of the mass balance equations reproduces well the experimental data. The rate constants of the elementary processes determined are discussed. (orig.)

  9. Protocols for dry DNA storage and shipment at room temperature.

    Science.gov (United States)

    Ivanova, Natalia V; Kuzmina, Masha L

    2013-09-01

    The globalization of DNA barcoding will require core analytical facilities to develop cost-effective, efficient protocols for the shipment and archival storage of DNA extracts and PCR products. We evaluated three dry-state DNA stabilization systems: commercial Biomatrica(®) DNAstable(®) plates, home-made trehalose and polyvinyl alcohol (PVA) plates on 96-well panels of insect DNA stored at 56 °C and at room temperature. Controls included unprotected samples that were stored dry at room temperature and at 56 °C, and diluted samples held at 4 °C and at -20 °C. PCR and selective sequencing were performed over a 4-year interval to test the condition of DNA extracts. Biomatrica(®) provided better protection of DNA at 56 °C and at room temperature than trehalose and PVA, especially for diluted samples. PVA was the second best protectant after Biomatrica(®) at room temperature, whereas trehalose was the second best protectant at 56 °C. In spite of lower PCR success, the DNA stored at -20 °C yielded longer sequence reads and stronger signal, indicating that temperature is a crucial factor for DNA quality which has to be considered especially for long-term storage. Although it is premature to advocate a transition to DNA storage at room temperature, dry storage provides an additional layer of security for frozen samples, protecting them from degradation in the event of freezer failure. All three forms of DNA preservation enable shipment of dry DNA and PCR products between barcoding facilities. © 2013 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.

  10. Trivalent europium speciation in a room-temperature ionic liquid

    International Nuclear Information System (INIS)

    Mekki, S.

    2006-10-01

    Since the nuclear industry is playing an important role in the power production field, a relevant number of problems have been revealed. Indeed, high-level radioactive long-lived nuclear wastes present a real difficulty for nuclear wastes management. Minor actinides, which compose most of these wastes, will be radioactive for several thousands of years. For eventual disposal deep underground, their reprocessing needs to be optimized. The extraction processes used industrially to separate actinides and lanthanides from other metal species characterizing the spent nuclear fuel produce, nevertheless, enormous quantities of contaminated liquid wastes directly issued from the liquid/liquid extraction step. During the last decade, some room-temperature ionic liquid have been studied and integrated into industrial processes. The interest on this class of solvent came out from their 'green' properties (non volatile, non flammable, recyclable, etc...), but also from the variability of their physico-chemical properties (stability, hydrophobicity, viscosity) as a function of the RTIL chemical composition. Indeed, it has been shown that classical chemical industrial processes could be transferred into those media, even more improved, while a certain number of difficulties arising from using traditional solvent can be avoided. In this respect, it could be promising to investigate the ability to use room-temperature ionic liquid into the spent nuclear fuel reprocessing field. The aim of this thesis is to test the ability of the specific ionic liquid bumimTf 2 N to allow trivalent europium extraction. The choice of this metal is based on the chemical analogy with trivalent minor actinides Curium and Americium which are contributing the greatest part of the long-lived high-level radioactive wastes. Handling these elements needs to be very cautious for the safety and radioprotection aspect. Moreover, europium is a very sensitive luminescent probe to its environment even at the

  11. In-situ investigation of the microstructure evolution in nanocrystalline copper electrodeposits at room temperature

    DEFF Research Database (Denmark)

    Pantleon, Karen; Somers, Marcel A. J.

    2006-01-01

    The microstructure evolution in copper electrodeposits at room temperature (self-annealing) was investigated by means of x-ray diffraction analysis and simultaneous measurements of the electrical resistivity as a function of time. In situ studies were started immediately after deposition...... growth, crystallographic texture changes by multiple twinning, and a decrease of the electrical resistivity occurred as a function of time at room temperature. The kinetics of self-annealing is strongly affected by the layer thickness: the thinner the layer, the slower the microstructure evolution is......, and self-annealing is suppressed completely for a thin layer with 0.4 µm. The preferred crystallographic orientation of the as-deposited crystallites is suggested to cause the observed thickness dependence of the self-annealing kinetics. ©2006 American Institute of Physics...

  12. Room-Temperature Alternative to the Arbuzov Reaction: The Reductive Deoxygenation of Acyl Phosphonates

    OpenAIRE

    Kedrowski, Sean M. A.; Dougherty, Dennis A.

    2010-01-01

    The reductive deoxygenation of acyl phosphonates using a Wolff−Kishner-like sequence is described. This transformation allows direct access to alkyl phosphonates from acyl phosphonates at room temperature. The method can be combined with acyl phosphonate synthesis into a one pot, four-step procedure for the conversion of carboxylic acids into alkyl phosphonates. The methodology works well for a variety of aliphatic acids and shows a functional group tolerance similar to that of other hydrazon...

  13. Metal nanoparticle film-based room temperature Coulomb transistor.

    Science.gov (United States)

    Willing, Svenja; Lehmann, Hauke; Volkmann, Mirjam; Klinke, Christian

    2017-07-01

    Single-electron transistors would represent an approach to developing less power-consuming microelectronic devices if room temperature operation and industry-compatible fabrication were possible. We present a concept based on stripes of small, self-assembled, colloidal, metal nanoparticles on a back-gate device architecture, which leads to well-defined and well-controllable transistor characteristics. This Coulomb transistor has three main advantages. By using the scalable Langmuir-Blodgett method, we combine high-quality chemically synthesized metal nanoparticles with standard lithography techniques. The resulting transistors show on/off ratios above 90%, reliable and sinusoidal Coulomb oscillations, and room temperature operation. Furthermore, this concept allows for versatile tuning of the device properties such as Coulomb energy gap and threshold voltage, as well as period, position, and strength of the oscillations.

  14. Metal nanoparticle film–based room temperature Coulomb transistor

    Science.gov (United States)

    Willing, Svenja; Lehmann, Hauke; Volkmann, Mirjam; Klinke, Christian

    2017-01-01

    Single-electron transistors would represent an approach to developing less power–consuming microelectronic devices if room temperature operation and industry-compatible fabrication were possible. We present a concept based on stripes of small, self-assembled, colloidal, metal nanoparticles on a back-gate device architecture, which leads to well-defined and well-controllable transistor characteristics. This Coulomb transistor has three main advantages. By using the scalable Langmuir-Blodgett method, we combine high-quality chemically synthesized metal nanoparticles with standard lithography techniques. The resulting transistors show on/off ratios above 90%, reliable and sinusoidal Coulomb oscillations, and room temperature operation. Furthermore, this concept allows for versatile tuning of the device properties such as Coulomb energy gap and threshold voltage, as well as period, position, and strength of the oscillations. PMID:28740864

  15. Room temperature excitation spectroscopy of single quantum dots

    Directory of Open Access Journals (Sweden)

    Christian Blum

    2011-08-01

    Full Text Available We report a single molecule detection scheme to investigate excitation spectra of single emitters at room temperature. We demonstrate the potential of single emitter photoluminescence excitation spectroscopy by recording excitation spectra of single CdSe nanocrystals over a wide spectral range of 100 nm. The spectra exhibit emission intermittency, characteristic of single emitters. We observe large variations in the spectra close to the band edge, which represent the individual heterogeneity of the observed quantum dots. We also find specific excitation wavelengths for which the single quantum dots analyzed show an increased propensity for a transition to a long-lived dark state. We expect that the additional capability of recording excitation spectra at room temperature from single emitters will enable insights into the photophysics of emitters that so far have remained inaccessible.

  16. Room temperature Sieving of Hydrogen Isotopes Using 2-D Materials

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Krentz, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Serkiz, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Velten, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Xiao, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-28

    Hydrogen isotope separation is critical to the DOE’s mission in environmental remediation and nuclear nonproliferation. Isotope separation is also a critical technology for the NNSA, and the ability to perform the separations at room temperature with a relatively small amount of power and space would be a major advancement for their respective missions. Recent work has shown that 2-D materials such as graphene and hexagonal boron nitride can act as an isotopic sieve at room temperature; efficiently separating hydrogen isotopes in water with reported separation ratios of 10:1 for hydrogen: deuterium separation for a single pass. The work performed here suggests that this technique has merit, and furthermore, we are investigating optimization and scale up of the required 2-D material based membranes.

  17. Mechanical Resonators for Quantum Optomechanics Experiments at Room Temperature.

    Science.gov (United States)

    Norte, R A; Moura, J P; Gröblacher, S

    2016-04-08

    All quantum optomechanics experiments to date operate at cryogenic temperatures, imposing severe technical challenges and fundamental constraints. Here, we present a novel design of on-chip mechanical resonators which exhibit fundamental modes with frequencies f and mechanical quality factors Q_{m} sufficient to enter the optomechanical quantum regime at room temperature. We overcome previous limitations by designing ultrathin, high-stress silicon nitride (Si_{3}N_{4}) membranes, with tensile stress in the resonators' clamps close to the ultimate yield strength of the material. By patterning a photonic crystal on the SiN membranes, we observe reflectivities greater than 99%. These on-chip resonators have remarkably low mechanical dissipation, with Q_{m}∼10^{8}, while at the same time exhibiting large reflectivities. This makes them a unique platform for experiments towards the observation of massive quantum behavior at room temperature.

  18. Synthesis of cadmium chalcogenide nanotubes at room temperature

    KAUST Repository

    Pan, Jun

    2012-10-01

    Cadmium chalcogenide (CdE, E=S, Se, Te) polycrystalline nanotubes have been synthesized from precursor of CdS/cadmium thiolate complex at room temperature. The precursor was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The transformation from the rod-like precursor of CdS/cadmium thiolate complex to CdS, CdSe and CdTe nanotubes were performed under constant stirring at room temperature in aqueous solution containing S 2-, Se 2- and Te 2-, respectively. The nanotube diameter can be controlled from 150 to 400 nm related to the dimension of templates. The XRD patterns show the cadmium chalcogenide nanotubes all corresponding to face-centered cubic structure. © 2012 Elsevier B.V. All rights reserved.

  19. Synthesis of cadmium chalcogenide nanotubes at room temperature

    KAUST Repository

    Pan, Jun; Qian, Yitai

    2012-01-01

    Cadmium chalcogenide (CdE, E=S, Se, Te) polycrystalline nanotubes have been synthesized from precursor of CdS/cadmium thiolate complex at room temperature. The precursor was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The transformation from the rod-like precursor of CdS/cadmium thiolate complex to CdS, CdSe and CdTe nanotubes were performed under constant stirring at room temperature in aqueous solution containing S 2-, Se 2- and Te 2-, respectively. The nanotube diameter can be controlled from 150 to 400 nm related to the dimension of templates. The XRD patterns show the cadmium chalcogenide nanotubes all corresponding to face-centered cubic structure. © 2012 Elsevier B.V. All rights reserved.

  20. Room temperature electrodeposition of actinides from ionic solutions

    Science.gov (United States)

    Hatchett, David W.; Czerwinski, Kenneth R.; Droessler, Janelle; Kinyanjui, John

    2017-04-25

    Uranic and transuranic metals and metal oxides are first dissolved in ozone compositions. The resulting solution in ozone can be further dissolved in ionic liquids to form a second solution. The metals in the second solution are then electrochemically deposited from the second solutions as room temperature ionic liquid (RTIL), tri-methyl-n-butyl ammonium n-bis(trifluoromethansulfonylimide) [Me.sub.3N.sup.nBu][TFSI] providing an alternative non-aqueous system for the extraction and reclamation of actinides from reprocessed fuel materials. Deposition of U metal is achieved using TFSI complexes of U(III) and U(IV) containing the anion common to the RTIL. TFSI complexes of uranium were produced to ensure solubility of the species in the ionic liquid. The methods provide a first measure of the thermodynamic properties of U metal deposition using Uranium complexes with different oxidation states from RTIL solution at room temperature.

  1. Room-Temperature-Cured Copolymers for Lithium Battery Gel Electrolytes

    Science.gov (United States)

    Meador, Mary Ann B.; Tigelaar, Dean M.

    2009-01-01

    Polyimide-PEO copolymers (PEO signifies polyethylene oxide) that have branched rod-coil molecular structures and that can be cured into film form at room temperature have been invented for use as gel electrolytes for lithium-ion electric-power cells. These copolymers offer an alternative to previously patented branched rod-coil polyimides that have been considered for use as polymer electrolytes and that must be cured at a temperature of 200 C. In order to obtain sufficient conductivity for lithium ions in practical applications at and below room temperature, it is necessary to imbibe such a polymer with a suitable carbonate solvent or ionic liquid, but the high-temperature cure makes it impossible to incorporate and retain such a liquid within the polymer molecular framework. By eliminating the high-temperature cure, the present invention makes it possible to incorporate the required liquid.

  2. Concurrent transition of ferroelectric and magnetic ordering near room temperature.

    Science.gov (United States)

    Ko, Kyung-Tae; Jung, Min Hwa; He, Qing; Lee, Jin Hong; Woo, Chang Su; Chu, Kanghyun; Seidel, Jan; Jeon, Byung-Gu; Oh, Yoon Seok; Kim, Kee Hoon; Liang, Wen-I; Chen, Hsiang-Jung; Chu, Ying-Hao; Jeong, Yoon Hee; Ramesh, Ramamoorthy; Park, Jae-Hoon; Yang, Chan-Ho

    2011-11-29

    Strong spin-lattice coupling in condensed matter gives rise to intriguing physical phenomena such as colossal magnetoresistance and giant magnetoelectric effects. The phenomenological hallmark of such a strong spin-lattice coupling is the manifestation of a large anomaly in the crystal structure at the magnetic transition temperature. Here we report that the magnetic Néel temperature of the multiferroic compound BiFeO(3) is suppressed to around room temperature by heteroepitaxial misfit strain. Remarkably, the ferroelectric state undergoes a first-order transition to another ferroelectric state simultaneously with the magnetic transition temperature. Our findings provide a unique example of a concurrent magnetic and ferroelectric transition at the same temperature among proper ferroelectrics, taking a step toward room temperature magnetoelectric applications.

  3. Xenon Recovery at Room Temperature using Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Elsaidi, Sameh K. [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Chemistry Department, Faculty of Science, Alexandria University, P. O. Box 426 Ibrahimia Alexandria 21321 Egypt; Ongari, Daniele [Laboratory of Molecular Simulation, Institut des Sciences et Ingeénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Rue de l' Industrie 17 1951 Sion Valais Switzerland; Xu, Wenqian [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Mohamed, Mona H. [Chemistry Department, Faculty of Science, Alexandria University, P. O. Box 426 Ibrahimia Alexandria 21321 Egypt; Haranczyk, Maciej [IMDEA Materials Institute, c/Eric Kandel 2 28906 Getafe, Madrid Spain; Thallapally, Praveen K. [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA

    2017-07-24

    Xenon is known to be a very efficient anesthetic gas but its cost prohibits the wider use in medical industry and other potential applications. It has been shown that Xe recovery and recycle from anesthetic gas mixture can significantly reduce its cost as anesthetic. The current technology uses series of adsorbent columns followed by low temperature distillation to recover Xe, which is expensive to use in medical facilities. Herein, we propose much efficient and simpler system to recover and recycle Xe from simulant exhale anesthetic gas mixture at room temperature using metal organic frameworks. Among the MOFs tested, PCN-12 exhibits unprecedented performance with high Xe capacity, Xe/N2 and Xe/O2 selectivity at room temperature. The in-situ synchrotron measurements suggest the Xe is occupied in the small pockets of PCN-12 compared to unsaturated metal centers (UMCs). Computational modeling of adsorption further supports our experimental observation of Xe binding sites in PCN-12.

  4. Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature.

    Science.gov (United States)

    Kleemann, Marie-Elena; Chikkaraddy, Rohit; Alexeev, Evgeny M; Kos, Dean; Carnegie, Cloudy; Deacon, Will; de Pury, Alex Casalis; Große, Christoph; de Nijs, Bart; Mertens, Jan; Tartakovskii, Alexander I; Baumberg, Jeremy J

    2017-11-03

    Strong coupling of monolayer metal dichalcogenide semiconductors with light offers encouraging prospects for realistic exciton devices at room temperature. However, the nature of this coupling depends extremely sensitively on the optical confinement and the orientation of electronic dipoles and fields. Here, we show how plasmon strong coupling can be achieved in compact, robust, and easily assembled gold nano-gap resonators at room temperature. We prove that strong-coupling is impossible with monolayers due to the large exciton coherence size, but resolve clear anti-crossings for greater than 7 layer devices with Rabi splittings exceeding 135 meV. We show that such structures improve on prospects for nonlinear exciton functionalities by at least 10 4 , while retaining quantum efficiencies above 50%, and demonstrate evidence for superlinear light emission.

  5. Micelle-stabilized room-temperature phosphorescence with synchronous scanning

    International Nuclear Information System (INIS)

    Femia, R.A.; Love, L.J.C.

    1984-01-01

    The experimental requirements for synchronous wavelength scanning micelle-stabilized room temperature phosphorescence and the factors affecting peak resolution are presented and compared with those for synchronous wavelength scanning fluorescence. Identification of individual compounds in a four-component mixture is illustrated, and criteria to identify and minimize triplet state energy transfer are given. Considerable improvement in resolution of the synchronous peaks is obtained via second derivative spectra. 20 references, 7 figures, 2 tables

  6. Adaptive Beam Loading Compensation in Room Temperature Bunching Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, J. P. [Fermilab; Chase, B. E. [Fermilab; Cullerton, E. [Fermilab; Varghese, P. [Fermilab

    2017-10-01

    In this paper we present the design, simulation, and proof of principle results of an optimization based adaptive feedforward algorithm for beam-loading compensation in a high impedance room temperature cavity. We begin with an overview of prior developments in beam loading compensation. Then we discuss different techniques for adaptive beam loading compensation and why the use of Newton?s Method is of interest for this application. This is followed by simulation and initial experimental results of this method.

  7. Room Temperature Ultralow Threshold GaN Nanowire Polariton Laser

    KAUST Repository

    Das, Ayan

    2011-08-01

    We report ultralow threshold polariton lasing from a single GaN nanowire strongly coupled to a large-area dielectric microcavity. The threshold carrier density is 3 orders of magnitude lower than that of photon lasing observed in the same device, and 2 orders of magnitude lower than any existing room-temperature polariton devices. Spectral, polarization, and coherence properties of the emission were measured to confirm polariton lasing. © 2011 American Physical Society.

  8. Room temperature ferromagnetism in Cu doped ZnO

    Science.gov (United States)

    Ali, Nasir; Singh, Budhi; Khan, Zaheer Ahmed; Ghosh, Subhasis

    2018-05-01

    We report the room temperature ferromagnetism in 2% Cu doped ZnO films grown by RF magnetron sputtering in different argon and oxygen partial pressure. X-ray photoelectron spectroscopy was used to ascertain the oxidation states of Cu in ZnO. The presence of defects within Cu-doped ZnO films can be revealed by electron paramagnetic resonance. It has been observed that saturated magnetic moment increase as we increase the zinc vacancies during deposition.

  9. A Room Temperature Low-Threshold Ultraviolet Plasmonic Nanolaser

    Science.gov (United States)

    2014-09-23

    samples were pasted to the cold finger of the cryostat with silver paste to ensure good thermal conduction. The time-resolve photoluminescence (TRPL...laser by total internal reflection. Nat. Mater. 10, 110–113 (2011). 13. Lu, Y. J. et al. Plasmonic nanolaser using epitaxially grown silver film. Science...1129 (1973). 30. Wang, Y. G. et al. Room temperature lasing with high group index in metal- coated GaN nanoring . Appl. Phys. Lett. 99, 251111 (2011

  10. Outrunning free radicals in room-temperature macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Robin L., E-mail: robin.owen@diamond.ac.uk; Axford, Danny [Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Nettleship, Joanne E.; Owens, Raymond J. [Rutherford Appleton Laboratory, Didcot OX11 0FA (United Kingdom); The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Robinson, James I.; Morgan, Ann W. [University of Leeds, Leeds LS9 7FT (United Kingdom); Doré, Andrew S. [Heptares Therapeutics Ltd, BioPark, Welwyn Garden City AL7 3AX (United Kingdom); Lebon, Guillaume; Tate, Christopher G. [MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH (United Kingdom); Fry, Elizabeth E.; Ren, Jingshan [The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Stuart, David I. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Evans, Gwyndaf [Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

    2012-06-15

    A systematic increase in lifetime is observed in room-temperature protein and virus crystals through the use of reduced exposure times and a fast detector. A significant increase in the lifetime of room-temperature macromolecular crystals is reported through the use of a high-brilliance X-ray beam, reduced exposure times and a fast-readout detector. This is attributed to the ability to collect diffraction data before hydroxyl radicals can propagate through the crystal, fatally disrupting the lattice. Hydroxyl radicals are shown to be trapped in amorphous solutions at 100 K. The trend in crystal lifetime was observed in crystals of a soluble protein (immunoglobulin γ Fc receptor IIIa), a virus (bovine enterovirus serotype 2) and a membrane protein (human A{sub 2A} adenosine G-protein coupled receptor). The observation of a similar effect in all three systems provides clear evidence for a common optimal strategy for room-temperature data collection and will inform the design of future synchrotron beamlines and detectors for macromolecular crystallography.

  11. Outrunning free radicals in room-temperature macromolecular crystallography

    International Nuclear Information System (INIS)

    Owen, Robin L.; Axford, Danny; Nettleship, Joanne E.; Owens, Raymond J.; Robinson, James I.; Morgan, Ann W.; Doré, Andrew S.; Lebon, Guillaume; Tate, Christopher G.; Fry, Elizabeth E.; Ren, Jingshan; Stuart, David I.; Evans, Gwyndaf

    2012-01-01

    A systematic increase in lifetime is observed in room-temperature protein and virus crystals through the use of reduced exposure times and a fast detector. A significant increase in the lifetime of room-temperature macromolecular crystals is reported through the use of a high-brilliance X-ray beam, reduced exposure times and a fast-readout detector. This is attributed to the ability to collect diffraction data before hydroxyl radicals can propagate through the crystal, fatally disrupting the lattice. Hydroxyl radicals are shown to be trapped in amorphous solutions at 100 K. The trend in crystal lifetime was observed in crystals of a soluble protein (immunoglobulin γ Fc receptor IIIa), a virus (bovine enterovirus serotype 2) and a membrane protein (human A 2A adenosine G-protein coupled receptor). The observation of a similar effect in all three systems provides clear evidence for a common optimal strategy for room-temperature data collection and will inform the design of future synchrotron beamlines and detectors for macromolecular crystallography

  12. A room temperature light source based on silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Lo Faro, M.J. [CNR-IPCF, Istituto per i Processi Chimico-Fisici, V. le F. Stagno D' Alcontres 37, 98158 Messina (Italy); MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania (Italy); D' Andrea, C. [MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania (Italy); Messina, E.; Fazio, B. [CNR-IPCF, Istituto per i Processi Chimico-Fisici, V. le F. Stagno D' Alcontres 37, 98158 Messina (Italy); Musumeci, P. [Dipartimento di Fisica e Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania (Italy); Franzò, G. [MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania (Italy); Gucciardi, P.G.; Vasi, C. [CNR-IPCF, Istituto per i Processi Chimico-Fisici, V. le F. Stagno D' Alcontres 37, 98158 Messina (Italy); Priolo, F. [MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania (Italy); Scuola Superiore di Catania, Via Valdisavoia 9, 95123 Catania (Italy); Iacona, F. [MATIS CNR-IMM, Istituto per la Microelettronica e Microsistemi, Via Santa Sofia 64, 95123 Catania (Italy); Irrera, A., E-mail: irrera@me.cnr.it [CNR-IPCF, Istituto per i Processi Chimico-Fisici, V. le F. Stagno D' Alcontres 37, 98158 Messina (Italy)

    2016-08-31

    We synthesized ultrathin Si nanowires (NWs) by metal assisted chemical wet etching, using a very thin discontinuous Au layer as precursor for the process. A bright room temperature emission in the visible range due to electron–hole recombination in quantum confined Si NWs is reported. A single walled carbon nanotube (CNT) suspension was prepared and dispersed in Si NW samples. The hybrid Si NW/CNT system exhibits a double emission at room temperature, both in the visible (due to Si NWs) and the IR (due to CNTs) range, thus demonstrating the realization of a low-cost material with promising perspectives for applications in Si-based photonics. - Highlights: • Synthesis of ultrathin Si nanowires (NWs) by metal-assisted chemical etching • Synthesis of NW/carbon nanotube (CNT) hybrid systems • Structural characterization of Si NWs and Si NW/CNT • Room temperature photoluminescence (PL) properties of Si NWs and of Si NW/CNT • Tuning of the PL properties of the Si NW/CNT hybrid system.

  13. Continuous-wave room-temperature diamond maser

    Science.gov (United States)

    Breeze, Jonathan D.; Salvadori, Enrico; Sathian, Juna; Alford, Neil Mcn.; Kay, Christopher W. M.

    2018-03-01

    The maser—the microwave progenitor of the optical laser—has been confined to relative obscurity owing to its reliance on cryogenic refrigeration and high-vacuum systems. Despite this, it has found application in deep-space communications and radio astronomy owing to its unparalleled performance as a low-noise amplifier and oscillator. The recent demonstration of a room-temperature solid-state maser that utilizes polarized electron populations within the triplet states of photo-excited pentacene molecules in a p-terphenyl host paves the way for a new class of maser. However, p-terphenyl has poor thermal and mechanical properties, and the decay rates of the triplet sublevel of pentacene mean that only pulsed maser operation has been observed in this system. Alternative materials are therefore required to achieve continuous emission: inorganic materials that contain spin defects, such as diamond and silicon carbide, have been proposed. Here we report a continuous-wave room-temperature maser oscillator using optically pumped nitrogen–vacancy defect centres in diamond. This demonstration highlights the potential of room-temperature solid-state masers for use in a new generation of microwave devices that could find application in medicine, security, sensing and quantum technologies.

  14. An azumamide C analogue without the zinc-binding functionality

    DEFF Research Database (Denmark)

    Villadsen, Jesper; Kitir, Betül; Wich, Kathrine

    2014-01-01

    + - coordinating moiety. Herein, we describe the synthesis of an azumamide analogue lacking its native Zn 2+ -binding group and evaluation of its inhibitory activity against recombinant human HDAC1 – 11. Furthermore, kinetic investigation of the inhibitory mechanism of both parent natural product and synthetic...

  15. Thermomechanical analysis of Natural Rubber behaviour stressed at room temperature.

    Directory of Open Access Journals (Sweden)

    Chrysochoos A.

    2010-06-01

    Full Text Available Owing to their high molecular mobility, stressed rubber chains can easily change their conformations and get orientated. This phenomena leads to so high reversible draw ratio that this behaviour is called rubber elasticity [1-3]. The analogy with ideal gases leads to an internal energy independent of elongation, the stress being attributed to a so-called configuration entropy. However, this analysis cannot take thermal expansion into account and moreover prohibits predicting standard thermo-elastic effect noticed at small elongations and the thermoelastic inversion effects [4]. This paper aims at : observing and quantifying dissipative and coupling effects associated with deformation energy, generated when Natural Rubber is stretched. re-examine the thermomechanical behaviour model of rubberlike materials, under the generalised standard material concept. From an experimental viewpoint, energy balance is created using infrared and quantitative imaging techniques. Digital Image Correlation (DIC provides in-the-plane displacement fields and, after derivation, strain and strain-rate fields. We have used those techniques to evidence the thermoelastic inversion effect as shown on Figure 1 where different weights have been fixed to warmed specimen and we monitored the sample deformation while it recovers room temperature. But we have also used those techniques to perform energy balance : analysis of the mechanical equilibrium allows estimates of the stress pattern and computation of deformation energy rates under a plane stress hypothesis [5]. Infrared Thermography (IRT gives the surface temperature of the sample. To estimate the distribution of heat sources, image processing with a local heat equation and a minimal set of approximation functions (image filtering was used. The time courses of deformation energy and heat associated with cyclic process are plotted in Figure 2. The time derivatives of both forms of energy are approximately similar. This

  16. Conformational variation of proteins at room temperature is not dominated by radiation damage

    International Nuclear Information System (INIS)

    Russi, Silvia; González, Ana; Kenner, Lillian R.; Keedy, Daniel A.; Fraser, James S.; Bedem, Henry van den

    2017-01-01

    Protein crystallography data collection at synchrotrons is routinely carried out at cryogenic temperatures to mitigate radiation damage. Although damage still takes place at 100 K and below, the immobilization of free radicals increases the lifetime of the crystals by approximately 100-fold. Recent studies have shown that flash-cooling decreases the heterogeneity of the conformational ensemble and can hide important functional mechanisms from observation. These discoveries have motivated increasing numbers of experiments to be carried out at room temperature. However, the trade-offs between increased risk of radiation damage and increased observation of alternative conformations at room temperature relative to cryogenic temperature have not been examined. A considerable amount of effort has previously been spent studying radiation damage at cryo-temperatures, but the relevance of these studies to room temperature diffraction is not well understood. Here, the effects of radiation damage on the conformational landscapes of three different proteins (T. danielli thaumatin, hen egg-white lysozyme and human cyclophilin A) at room (278 K) and cryogenic (100 K) temperatures are investigated. Increasingly damaged datasets were collected at each temperature, up to a maximum dose of the order of 10 7 Gy at 100 K and 10 5 Gy at 278 K. Although it was not possible to discern a clear trend between damage and multiple conformations at either temperature, it was observed that disorder, monitored by B-factor-dependent crystallographic order parameters, increased with higher absorbed dose for the three proteins at 100 K. At 278 K, however, the total increase in this disorder was only statistically significant for thaumatin. A correlation between specific radiation damage affecting side chains and the amount of disorder was not observed. Lastly, this analysis suggests that elevated conformational heterogeneity in crystal structures at room temperature is observed despite radiation

  17. Origin of Ferrimagnetism and Ferroelectricity in Room-Temperature Multiferroic ɛ -Fe2O3

    Science.gov (United States)

    Xu, K.; Feng, J. S.; Liu, Z. P.; Xiang, H. J.

    2018-04-01

    Exploring and identifying room-temperature multiferroics is critical for developing better nonvolatile random-access memory devices. Recently, ɛ -Fe2O3 was found to be a promising room-temperature multiferroic with a large polarization and magnetization. However, the origin of the multiferroicity in ɛ -Fe2O3 is still puzzling. In this work, we perform density-functional-theory calculations to reveal that the spin frustration between tetrahedral-site Fe3 + spins gives rise to the unexpected ferrimagnetism. For the ferroelectricity, we identify a low-energy polarization switching path with an energy barrier of 85 meV /f .u . by performing a stochastic surface walking simulation. The switching of the ferroelectric polarization is achieved by swapping the tetrahedral Fe ion with the octahedral Fe ion, different from the usual case (e.g., in BaTiO3 and BiFeO3 ) where the coordination number remains unchanged after the switching. Our results not only confirm that ɛ -Fe2O3 is a promising room-temperature multiferroic but also provide guiding principles to design high-performance multiferroics.

  18. Room temperature ferromagnetism in ZnO prepared by microemulsion

    Directory of Open Access Journals (Sweden)

    Qingyu Xu

    2011-09-01

    Full Text Available Clear room temperature ferromagnetism has been observed in ZnO powders prepared by microemulsion. The O vacancy (VO clusters mediated by the VO with one electron (F center contributed to the ferromagnetism, while the isolated F centers contributed to the low temperature paramagnetism. Annealing in H2 incorporated interstitial H (Hi in ZnO, and removed the isolated F centers, leading to the suppression of the paramagnetism. The ferromagnetism has been considered to originate from the VO clusters mediated by the Hi, leading to the enhancement of the coercivity. The ferromagnetism disappeared after annealing in air due to the reduction of Hi.

  19. Room-Temperature Dephasing in InAs Quantum Dots

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Mørk, Jesper

    2000-01-01

    The room temperature dephasing in InAs/InGaAs/GaAs self-assembled quantum dots, embedded in a waveguide for laser applications, is measured using two independent methods: spectral hole burning and four-wave mixing. Without the application of bias current for electrical carrier injection......, a dephasing time of ~260 fs, weakly dependent on the optical excitation density, is found and attributed to phonon interaction. The application of bias current, leading to population inversion in the dot ground state and optical gain, strongly decreases the dephasing time to less than 50 fs, likely due...

  20. Thermoluminescence in KBr:D electron irradiated at room temperature

    International Nuclear Information System (INIS)

    Paredes Campoy, J.C.; Lopez Carranza, E.

    1991-07-01

    The thermoluminescence of KBr:D samples electron irradiated at room temperature after thermal annealing at 673 K for 1 hour have been studied in the temperature range 360-730 K. The experimental TL-curve was discomposed by computer analysis in seven overlapping TL peaks, giving for them the order of the kinetics of thermal stimulation, the activation energy, the frequency factor, the relative values of the electronic concentration in traps at the initial heating temperature and the temperature at the maximum of the peak. (author). 18 refs, 1 fig., 3 tabs

  1. Room temperature deposition of magnetite thin films on organic substrate

    International Nuclear Information System (INIS)

    Arisi, E.; Bergenti, I.; Cavallini, M.; Murgia, M.; Riminucci, A.; Ruani, G.; Dediu, V.

    2007-01-01

    We report on the growth of magnetite films directly on thin layers of organic semiconductors by means of an electron beam ablation method. The deposition was performed at room temperature in a reactive plasma atmosphere. Thin films show ferromagnetic (FM) hysteresis loops and coercive fields of hundreds of Oersted. Micro Raman analysis indicates no presence of spurious phases. The morphology of the magnetite film is strongly influenced by the morphology of the underlayer of the organic semiconductor. These results open the way for the application of magnetite thin films in the field of organic spintronics

  2. Scaling of dynamical decoupling for a single electron spin in nanodiamonds at room temperature

    International Nuclear Information System (INIS)

    Liu, Dong-Qi; Liu, Gang-Qin; Chang, Yan-Chun; Pan, Xin-Yu

    2014-01-01

    Overcoming the spin qubit decoherence is a challenge for quantum science and technology. We investigate the decoherence process in nanodiamonds by Carr–Purcell–Meiboom–Gill (CPMG) technique at room temperature. We find that the coherence time T 2 scales as n γ . The elongation effect of coherence time can be represented by a constant power of the number of pulses n. Considering the filter function of CPMG decoupling sequence as a δ function, the spectrum density of noise has been reconstructed directly from the coherence time measurements and a Lorentzian noise power spectrum model agrees well with the experiment. These results are helpful for the application of nanodiamonds to nanoscale magnetic imaging

  3. Rhodium-catalyzed C-H alkynylation of arenes at room temperature.

    Science.gov (United States)

    Feng, Chao; Loh, Teck-Peng

    2014-03-03

    The rhodium(III)-catalyzed ortho C-H alkynylation of non-electronically activated arenes is disclosed. This process features a straightforward and highly effective protocol for the synthesis of functionalized alkynes and represents the first example of merging a hypervalent iodine reagent with rhodium(III) catalysis. Notably, this reaction proceeds at room temperature, tolerates a variety of functional groups, and more importantly, exhibits high selectivity for monoalkynylation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Uniaxial ratcheting behavior of Zircaloy-4 tubes at room temperature

    International Nuclear Information System (INIS)

    Wen, Mingjian; Li, Hua; Yu, Dunji; Chen, Gang; Chen, Xu

    2013-01-01

    In this study, a series of uniaxial tensile, strain cycling and uniaxial ratcheting tests were conducted at room temperature on Zircaloy-4 (Zr-4) tubes used as nuclear fuel cladding in Pressurized Water Reactors (PWRs) for the purpose to investigate the uniaxial ratcheting behavior of Zr-4 and the factors which may influence it. The experimental results show that at room temperature this material features cyclic softening remarkably within the strain range of 1.6%, and former cycling under larger strain amplitude cannot retard cyclic softening of later cycling under lower strain amplitude. Uniaxial ratcheting strain accumulates in the direction of mean stress, and the ratcheting stain level is larger under tensile mean stress than that under compressive mean stress. Uniaxial ratcheting strain level increases with the increase of mean stress and stress amplitude, and decreases with the increase of loading rate. The sequence of loading rate appears to have no effects on the final ratcheting strain accumulation. Loading history has great influence on the uniaxial ratcheting behavior. Lower stress level after loading history with higher stress level leads to the shakedown of ratcheting. Higher loading rate after loading history with lower loading rate brings down the ratcheting strain rate. Uniaxial ratcheting behavior is sensitive to compressive pre-strain, and the decay rate of the ratcheting strain rate is slowed down by pre-compression

  5. CuInP₂S₆ Room Temperature Layered Ferroelectric.

    Science.gov (United States)

    Belianinov, A; He, Q; Dziaugys, A; Maksymovych, P; Eliseev, E; Borisevich, A; Morozovska, A; Banys, J; Vysochanskii, Y; Kalinin, S V

    2015-06-10

    We explore ferroelectric properties of cleaved 2-D flakes of copper indium thiophosphate, CuInP2S6 (CITP), and probe size effects along with limits of ferroelectric phase stability, by ambient and ultra high vacuum scanning probe microscopy. CITP belongs to the only material family known to display ferroelectric polarization in a van der Waals, layered crystal at room temperature and above. Our measurements directly reveal stable, ferroelectric polarization as evidenced by domain structures, switchable polarization, and hysteresis loops. We found that at room temperature the domain structure of flakes thicker than 100 nm is similar to the cleaved bulk surfaces, whereas below 50 nm polarization disappears. We ascribe this behavior to a well-known instability of polarization due to depolarization field. Furthermore, polarization switching at high bias is also associated with ionic mobility, as evidenced both by macroscopic measurements and by formation of surface damage under the tip at a bias of 4 V-likely due to copper reduction. Mobile Cu ions may therefore also contribute to internal screening mechanisms. The existence of stable polarization in a van-der-Waals crystal naturally points toward new strategies for ultimate scaling of polar materials, quasi-2D, and single-layer materials with advanced and nonlinear dielectric properties that are presently not found in any members of the growing "graphene family".

  6. Does nanocrystalline Cu deform by Coble creep near room temperature?

    International Nuclear Information System (INIS)

    Li, Y.J.; Blum, W.; Breutinger, F.

    2004-01-01

    The proposal that nanocrystalline Cu produced by electro deposition (ED) creeps at temperatures slightly above room temperature by diffusive flow via grain boundaries (Coble creep) has been checked by compression tests. It was found that the minimum creep rates obtained in tension are significantly larger than those in compression, probably due to interference of tensile fracture. Scanning electron microscopic investigation showed that the spacing between large-angle grain boundaries is about 10 μm rather than the reported value of 30 nm. Comparison with coarse grained and ultrafine grained Cu produced by equal channel angular pressing showed that the ED-Cu work hardens similarly to coarse grained Cu in contrast to ultrafine grained Cu which reaches its maximum deformation resistance within a small strain interval of 0.04 and has distinctly higher strain rate sensitivity of flow stress. The present results are consistent with the established knowledge that there is no softening by grain boundaries, e.g. due to Coble creep, near room temperature in Cu with grain sizes above 1 μm. The grain boundary effect observed in ultrafine grained Cu is interpreted in terms of modification of dislocation generation and dislocation annihilation by grain boundaries

  7. Chemical synthesis of Cu2Se nanoparticles at room temperature

    International Nuclear Information System (INIS)

    Rong, Fengxia; Bai, Yan; Chen, Tianfeng; Zheng, Wenjie

    2012-01-01

    Graphical abstract: The Cu 2 Se nanoparticles were synthesized by a simple and rapid method at room temperature. The TEM and SEM images show that the Cu 2 Se nanoparticles were spherical. Highlights: ► Cu 2 Se nanoparticles were synthesized by the reaction of nanoSe 0 sol with Cu + ions. ► The Cu 2 Se nanoparticles were spherical with cubic structure and well crystallized. ► Optical and electrochemical properties of Cu 2 Se nanoparticles were observed. ► The formation mechanism of Cu 2 Se nanoparticles was proposed. -- Abstract: A simple and rapid method has been developed to synthesize cuprous selenide (Cu 2 Se) nanoparticles by the reaction of selenium nanoparticles sol with copper sulfate solution containing ascorbic acid at room temperature. Cu 2 Se nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray analysis (EDX). The results indicated that Cu 2 Se nanoparticles were cubic crystal structure and spherical with the diameter about 75 nm. The ultraviolet–visible absorption spectrum (UV–vis) and cyclic voltammetry of Cu 2 Se nanoparticles were also investigated. The optical band gap energy of Cu 2 Se nanoparticles was 1.94 eV. On the basis of a series of experiments and characterizations, the formation mechanism of Cu 2 Se nanoparticles was discussed.

  8. Room-temperature atmospheric pressure plasma plume for biomedical applications

    International Nuclear Information System (INIS)

    Laroussi, M.; Lu, X.

    2005-01-01

    As low-temperature nonequilibrium plasmas come to play an increasing role in biomedical applications, reliable and user-friendly sources need to be developed. These plasma sources have to meet stringent requirements such as low temperature (at or near room temperature), no risk of arcing, operation at atmospheric pressure, preferably hand-held operation, low concentration of ozone generation, etc. In this letter, we present a device that meets exactly such requirements. This device is capable of generating a cold plasma plume several centimeters in length. It exhibits low power requirements as shown by its current-voltage characteristics. Using helium as a carrier gas, very little ozone is generated and the gas temperature, as measured by emission spectroscopy, remains at room temperature even after hours of operations. The plasma plume can be touched by bare hands and can be directed manually by a user to come in contact with delicate objects and materials including skin and dental gum without causing any heating or painful sensation

  9. Synthesis of manganese spinel nanoparticles at room temperature by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Giovannelli, F., E-mail: fabien.giovannelli@univ-tours.fr [GREMAN, UMR 7347 CNRS-CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 BLOIS (France); Autret-Lambert, C.; Mathieu, C.; Chartier, T.; Delorme, F. [GREMAN, UMR 7347 CNRS-CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 BLOIS (France); Seron, A [BRGM, 3 Avenue Claude Guillemin, BP 36009, 45060 ORLEANS Cedex 2 (France)

    2012-08-15

    This paper is focused on a new route to synthesize Mn{sub 3}O{sub 4} nanoparticles by alkalisation by sodium hydroxide on a manganeous solution at room temperature. The precipitates obtained at different pH values have been characterized by XRD and TEM. Since the first addition of sodium hydroxide, a white Mn(OH){sub 2} precipitate appears. At pH=7, {gamma}-MnOOH phase is predominant with needle like shaped particles. At pH=10, hausmanite nanoparticles, which exhibits well defined cubic shape in the range 50-120 nm are obtained. This new precipitation route is a fast and easy environmentally friendly process to obtain well crystallized hausmanite nanoparticles. - Graphical abstract: TEM image showing Mn{sub 3}O{sub 4} particles after a precipitation at pH=10. Highlights: Black-Right-Pointing-Pointer A new route to synthesize Mn{sub 3}O{sub 4} nanoparticles has been demonstrated. Black-Right-Pointing-Pointer Synthesis has been performed by precipitation at room temperature. Black-Right-Pointing-Pointer The size of the Mn{sub 3}O{sub 4} nanoparticles is between 50 and 120 nm.

  10. Unconditional polarization qubit quantum memory at room temperature

    Science.gov (United States)

    Namazi, Mehdi; Kupchak, Connor; Jordaan, Bertus; Shahrokhshahi, Reihaneh; Figueroa, Eden

    2016-05-01

    The creation of global quantum key distribution and quantum communication networks requires multiple operational quantum memories. Achieving a considerable reduction in experimental and cost overhead in these implementations is thus a major challenge. Here we present a polarization qubit quantum memory fully-operational at 330K, an unheard frontier in the development of useful qubit quantum technology. This result is achieved through extensive study of how optical response of cold atomic medium is transformed by the motion of atoms at room temperature leading to an optimal characterization of room temperature quantum light-matter interfaces. Our quantum memory shows an average fidelity of 86.6 +/- 0.6% for optical pulses containing on average 1 photon per pulse, thereby defeating any classical strategy exploiting the non-unitary character of the memory efficiency. Our system significantly decreases the technological overhead required to achieve quantum memory operation and will serve as a building block for scalable and technologically simpler many-memory quantum machines. The work was supported by the US-Navy Office of Naval Research, Grant Number N00141410801 and the Simons Foundation, Grant Number SBF241180. B. J. acknowledges financial assistance of the National Research Foundation (NRF) of South Africa.

  11. Magnetic refrigeration--towards room-temperature applications

    International Nuclear Information System (INIS)

    Brueck, E.; Tegus, O.; Li, X.W.; Boer, F.R. de; Buschow, K.H.J.

    2003-01-01

    Modern society relies very much on readily available cooling. Magnetic refrigeration based on the magneto-caloric effect (MCE) has become a promising competitive technology for the conventional gas-compression/expansion technique in use today. Recently, there have been two breakthroughs in magnetic-refrigeration research: one is that American scientists demonstrated the world's first room-temperature, permanent-magnet, magnetic refrigerator; the other one is that we discovered a new class of magnetic refrigerant materials for room-temperature applications. The new materials are manganese-iron-phosphorus-arsenic (MnFe(P,As)) compounds. This new material has important advantages over existing magnetic coolants: it exhibits a huge MCE, which is larger than that of Gd metal; and its operating temperature can be tuned from about 150 to about 335 K by adjusting the P/As ratio. Here we report on further improvement of the materials by increasing the Mn content. The large entropy change is attributed to a field-induced first-order phase transition enhancing the effect of the applied magnetic field. Addition of Mn reduces the thermal hysteresis, which is intrinsic to the first-order transition. This implies that already moderate applied magnetic fields of below 2 T may suffice

  12. Xenon Recovery at Room Temperature using Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Elsaidi, Sameh K. [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Chemistry Department, Faculty of Science, Alexandria University, P. O. Box 426 Ibrahimia Alexandria 21321 Egypt; Ongari, Daniele [Laboratory of Molecular Simulation, Institut des Sciences et Ingeénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Rue de l' Industrie 17 1951 Sion Valais Switzerland; Xu, Wenqian [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Mohamed, Mona H. [Chemistry Department, Faculty of Science, Alexandria University, P. O. Box 426 Ibrahimia Alexandria 21321 Egypt; Haranczyk, Maciej [IMDEA Materials Institute, c/Eric Kandel 2 28906 Getafe, Madrid Spain; Thallapally, Praveen K. [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA

    2017-07-24

    Xenon is known to be a very efficient anesthetic gas but its cost prohibits the wider use in medical industry and other potential applications. It has been shown that Xe recovery and recycle from anesthetic gas mixture can significantly reduce its cost as anesthetic. The current technology uses series of adsorbent columns followed by low temperature distillation to recover Xe, which is expensive to use in medical facilities. Herein, we propose much efficient and simpler system to recover and recycle Xe from simulant exhale anesthetic gas mixture at room temperature using metal organic frameworks. Among the MOFs tested, PCN-12 exhibits unprecedented performance with high Xe capacity, Xe/O2, Xe/N2 and Xe/CO2 selectivity at room temperature. The in-situ synchrotron measurements suggest the Xe is occupied in the small pockets of PCN-12 compared to unsaturated metal centers (UMCs). Computational modeling of adsorption further supports our experimental observation of Xe binding sites in PCN-12.

  13. Room temperature inductively coupled plasma etching of InAs/InSb in BCl 3/Cl 2/Ar

    KAUST Repository

    Sun, Jian; Kosel, Jü rgen

    2012-01-01

    Inductively coupled plasma (ICP) etching of InAs and InSb at room temperature has been investigated using BCl 3/Cl 2/Ar plasma. Specifically, the etch rate and post-etching surface morphology were investigated as functions of the gas composition

  14. Multi-podant diglycolamides and room temperature ionic liquid impregnated resins: an excellent combination for extraction chromatography of actinides

    NARCIS (Netherlands)

    Gujar, R.B.; Ansari, S.A.; Verboom, Willem; Mohapatra, P.K.

    2016-01-01

    Extraction chromatography resins, prepared by impregnating two multi-podant diglycolamide ligands, viz. diglycolamide-functionalized calix[4]arene (C4DGA) and tripodal diglycolamide (T-DGA) dissolved in the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide

  15. Tunable, Room Temperature THZ Emitters Based on Nonlinear Photonics

    Science.gov (United States)

    Sinha, Raju

    The Terahertz (1012 Hz) region of the electromagnetic spectrum covers the frequency range from roughly 300 GHz to 10 THz, which is in between the microwave and infrared regimes. The increasing interest in the development of ultra-compact, tunable room temperature Terahertz (THz) emitters with wide-range tunability has stimulated in-depth studies of different mechanisms of THz generation in the past decade due to its various potential applications such as biomedical diagnosis, security screening, chemical identification, life sciences and very high speed wireless communication. Despite the tremendous research and development efforts, all the available state-of-the-art THz emitters suffer from either being large, complex and costly, or operating at low temperatures, lacking tunability, having a very short spectral range and a low output power. Hence, the major objective of this research was to develop simple, inexpensive, compact, room temperature THz sources with wide-range tunability. We investigated THz radiation in a hybrid optical and THz micro-ring resonators system. For the first time, we were able to satisfy the DFG phase matching condition for the above-mentioned THz range in one single device geometry by employing a modal phase matching technique and using two separately designed resonators capable of oscillating at input optical waves and generated THz waves. In chapter 6, we proposed a novel plasmonic antenna geometry – the dimer rod-tapered antenna (DRTA), where we created a hot-spot in the nanogap between the dimer arms with a very large intensity enhancement of 4.1x105 at optical resonant wavelength. Then, we investigated DFG operation in the antenna geometry by incorporating a nonlinear nanodot in the hot-spot of the antenna and achieved continuously tunable enhanced THz radiation across 0.5-10 THz range. In chapter 8, we designed a multi-metallic resonators providing an ultrasharp toroidal response at THz frequency, then fabricated and

  16. Etching characteristics of a CR-39 track detector at room temperature in different etching solutions

    International Nuclear Information System (INIS)

    Dajko, G.

    1991-01-01

    Investigations were carried out to discover how the etching characteristics of CR-39 detectors change with varying conditions of the etching process. Measurements were made at room temperature in pure NaOH and KOH solutions; in different alcoholic KOH solutions (PEW solution, i.e. potassium hydroxide, ethyl alcohol, water); and in NaOH and KOH solutions containing different additives. The bulk etching rate of the detector (V B ) and the V (= V T /V B ) function, i.e. track to bulk etch rates ratio, for 6.1 MeV α-particles, were measured systematically. (author)

  17. Catalytic chemical amide synthesis at room temperature: one more step toward peptide synthesis.

    Science.gov (United States)

    Mohy El Dine, Tharwat; Erb, William; Berhault, Yohann; Rouden, Jacques; Blanchet, Jérôme

    2015-05-01

    An efficient method has been developed for direct amide bond synthesis between carboxylic acids and amines via (2-(thiophen-2-ylmethyl)phenyl)boronic acid as a highly active bench-stable catalyst. This catalyst was found to be very effective at room temperature for a large range of substrates with slightly higher temperatures required for challenging ones. This methodology can be applied to aliphatic, α-hydroxyl, aromatic, and heteroaromatic acids as well as primary, secondary, heterocyclic, and even functionalized amines. Notably, N-Boc-protected amino acids were successfully coupled in good yields with very little racemization. An example of catalytic dipeptide synthesis is reported.

  18. Cu/Nitroxyl Catalyzed Aerobic Oxidation of Primary Amines into Nitriles at Room Temperature.

    Science.gov (United States)

    Kim, Jinho; Stahl, Shannon S

    2013-07-05

    An efficient catalytic method has been developed for aerobic oxidation of primary amines to the corresponding nitriles. The reactions proceed at room temperature and employ a catalyst consisting of (4,4'- t Bu 2 bpy)CuI/ABNO (ABNO = 9-azabicyclo[3.3.1]nonan-3-one N -oxyl). The reactions exhibit excellent functional group compatibility and substrate scope, and are effective with benzylic, allylic and aliphatic amines. Preliminary mechanistic studies suggest that aerobic oxidation of the Cu catalyst is the turnover-limiting step of the reaction.

  19. Cu/Nitroxyl Catalyzed Aerobic Oxidation of Primary Amines into Nitriles at Room Temperature

    OpenAIRE

    Kim, Jinho; Stahl, Shannon S.

    2013-01-01

    An efficient catalytic method has been developed for aerobic oxidation of primary amines to the corresponding nitriles. The reactions proceed at room temperature and employ a catalyst consisting of (4,4′-tBu2bpy)CuI/ABNO (ABNO = 9-azabicyclo[3.3.1]nonan-3-one N-oxyl). The reactions exhibit excellent functional group compatibility and substrate scope, and are effective with benzylic, allylic and aliphatic amines. Preliminary mechanistic studies suggest that aerobic oxidation of the Cu catalyst...

  20. Room temperature luminescence and ferromagnetism of AlN:Fe

    Energy Technology Data Exchange (ETDEWEB)

    Li, H., E-mail: lihui@mail.iee.ac.cn, E-mail: wjwang@aphy.iphy.ac.cn [The Key Laboratory of Solar Thermal Energy and Photovoltaic System, Institute of Electrical engineering, Chinese Academy of Sciences, Beijing 100190 (China); Cai, G. M. [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); Wang, W. J., E-mail: lihui@mail.iee.ac.cn, E-mail: wjwang@aphy.iphy.ac.cn [Research and Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2016-06-15

    AlN:Fe polycrystalline powders were synthesized by a modified solid state reaction (MSSR) method. Powder X-ray diffraction and transmission electron microscopy results reveal the single phase nature of the doped samples. In the doped AlN samples, Fe is in Fe{sup 2+} state. Room temperature ferromagnetic behavior is observed in AlN:Fe samples. Two photoluminescence peaks located at about 592 nm (2.09 eV) and 598 nm (2.07 eV) are observed in AlN:Fe samples. Our results suggest that AlN:Fe is a potential material for applications in spintronics and high power laser devices.

  1. Room temperature ferromagnetism in a phthalocyanine based carbon material

    International Nuclear Information System (INIS)

    Honda, Z.; Sato, K.; Sakai, M.; Fukuda, T.; Kamata, N.; Hagiwara, M.; Kida, T.

    2014-01-01

    We report on a simple method to fabricate a magnetic carbon material that contains nitrogen-coordinated transition metals and has a large magnetic moment. Highly chlorinated iron phthalocyanine was used as building blocks and potassium as a coupling reagent to uniformly disperse nitrogen-coordinated iron atoms on the phthalocyanine based carbon material. The iron phthalocyanine based carbon material exhibits ferromagnetic properties at room temperature and the ferromagnetic phase transition occurs at T c  = 490 ± 10 K. Transmission electron microscopy observation, X-ray diffraction analysis, and the temperature dependence of magnetization suggest that the phthalocyanine molecules form three-dimensional random networks in the iron phthalocyanine based carbon material

  2. Stretchable microelectrode array using room-temperature liquid alloy interconnects

    International Nuclear Information System (INIS)

    Wei, P; Ziaie, B; Taylor, R; Chung, C; Higgs, G; Pruitt, B L; Ding, Z; Abilez, O J

    2011-01-01

    In this paper, we present a stretchable microelectrode array for studying cell behavior under mechanical strain. The electrode array consists of gold-plated nail-head pins (250 µm tip diameter) or tungsten micro-wires (25.4 µm in diameter) inserted into a polydimethylsiloxane (PDMS) platform (25.4 × 25.4 mm 2 ). Stretchable interconnects to the outside were provided by fusible indium-alloy-filled microchannels. The alloy is liquid at room temperature, thus providing the necessary stretchability and electrical conductivity. The electrode platform can withstand strains of up to 40% and repeated (100 times) strains of up to 35% did not cause any failure in the electrodes or the PDMS substrate. We confirmed biocompatibility of short-term culture, and using the gold pin device, we demonstrated electric field pacing of adult murine heart cells. Further, using the tungsten microelectrode device, we successfully measured depolarizations of differentiated murine heart cells from embryoid body clusters

  3. Room Temperature Anodization of Aluminum at Low Voltage

    International Nuclear Information System (INIS)

    Kamal, A.; Abdel-Karim, R.; El-Raghy, S.; EL-Sherif, R.M.; Wheed, A.

    2013-01-01

    Membranes with nanometer-scale features have many applications, such as in optics, electronics, catalysis, selective molecule separation, filtration and purification, bio sensing, and single-molecule detection. Anodization process was conducted using 15, 20, 30 and 35% by volume phosphoric acid. Results showed that Porous Anodized Aluminum (PAA) with ideal nano pore arrays can be fabricated at room temperature by one-step anodization on high purity aluminum foil at 5 V. Morphology of the PAA was characterized by scanning electron microscopy (SEM). The electrochemical behavior of anodized aluminum was studied in 0.1 M Na 2 SO 4 solutions using electrochemical impedance spectroscopy (EIS). The highest resistance of the porous layer (R p ) was detected for the samples anodized in 20% phosphoric acid

  4. Modification of embedded Cu nanoparticles: Ion irradiation at room temperature

    International Nuclear Information System (INIS)

    Johannessen, B.; Kluth, P.; Giulian, R.; Araujo, L.L.; Llewellyn, D.J.; Foran, G.J.; Cookson, D.J.; Ridgway, M.C.

    2007-01-01

    Cu nanoparticles (NPs) with an average diameter of ∼25 A were synthesized in SiO 2 by ion implantation and thermal annealing. Subsequently, the NPs were exposed to ion irradiation at room temperature simultaneously with a bulk Cu reference film. The ion species/energy was varied to achieve different values for the nuclear energy loss. The short-range atomic structure and average NP diameter were measured by means of extended X-ray absorption fine structure spectroscopy and small angle X-ray scattering, respectively. Transmission electron microscopy yielded complementary results. The short-range order of the Cu films remained unchanged consistent with the high regeneration rate of bulk elemental metals. For the NP samples it was found that increasing nuclear energy loss yielded gradual dissolution of NPs. Furthermore, an increased structural disorder was observed for the residual NPs

  5. Reversible temper brittleness on tensile tests at room temperature

    International Nuclear Information System (INIS)

    Quadros, N.F. de; Cabral, U.Q.

    1976-01-01

    Tensile tests were carried out on unnotched test pieces at room temperature and three strain rates: 2,5x10 -4 , 2,5x10 -3 and 1,0x10 -2 s -1 in a low alloy No-Cr-Mo steel to observe the variation in its mechanical properties with the occurrence of reversible temper brittleness. The brittle samples showed a sensitivity of 50 0 C in a 48 hour heat treatment at 500 0 C. The tests showed that at the strain rate of 2,5x10 -4 s -1 there are statistically significant differences between the elongations of the material in the brittle and the nonbrittle and regenerated states. A short review of reversible temper brittleness is given and a theory suggested for the mechanism [pt

  6. Room temperature luminescence and ferromagnetism of AlN:Fe

    Directory of Open Access Journals (Sweden)

    H. Li

    2016-06-01

    Full Text Available AlN:Fe polycrystalline powders were synthesized by a modified solid state reaction (MSSR method. Powder X-ray diffraction and transmission electron microscopy results reveal the single phase nature of the doped samples. In the doped AlN samples, Fe is in Fe2+ state. Room temperature ferromagnetic behavior is observed in AlN:Fe samples. Two photoluminescence peaks located at about 592 nm (2.09 eV and 598 nm (2.07 eV are observed in AlN:Fe samples. Our results suggest that AlN:Fe is a potential material for applications in spintronics and high power laser devices.

  7. Room-temperature ferromagnetism in hydrogenated ZnO nanoparticles

    International Nuclear Information System (INIS)

    Xue, Xudong; Liu, Liangliang; Wang, Zhu; Wu, Yichu

    2014-01-01

    The effect of hydrogen doping on the magnetic properties of ZnO nanoparticles was investigated. Hydrogen was incorporated by annealing under 5% H 2 in Ar ambient at 700 °C. Room-temperature ferromagnetism was induced in hydrogenated ZnO nanoparticles, and the observed ferromagnetism could be switched between “on” and “off” states through hydrogen annealing and oxygen annealing process, respectively. It was found that Zn vacancy and OH bonding complex (V Zn  + OH) was crucial to the observed ferromagnetism by using the X-ray photoelectron spectroscopy and positron annihilation spectroscopy analysis. Based on first-principles calculations, V Zn  + OH was favorable to be presented due to the low formation energy. Meanwhile, this configuration could lead to a magnetic moment of 0.57 μ B . The Raman and photoluminescence measurements excluded the possibility of oxygen vacancy as the origin of the ferromagnetism

  8. Room-temperature ferromagnetism in hydrogenated ZnO nanoparticles

    Science.gov (United States)

    Xue, Xudong; Liu, Liangliang; Wang, Zhu; Wu, Yichu

    2014-01-01

    The effect of hydrogen doping on the magnetic properties of ZnO nanoparticles was investigated. Hydrogen was incorporated by annealing under 5% H2 in Ar ambient at 700 °C. Room-temperature ferromagnetism was induced in hydrogenated ZnO nanoparticles, and the observed ferromagnetism could be switched between "on" and "off" states through hydrogen annealing and oxygen annealing process, respectively. It was found that Zn vacancy and OH bonding complex (VZn + OH) was crucial to the observed ferromagnetism by using the X-ray photoelectron spectroscopy and positron annihilation spectroscopy analysis. Based on first-principles calculations, VZn + OH was favorable to be presented due to the low formation energy. Meanwhile, this configuration could lead to a magnetic moment of 0.57 μB. The Raman and photoluminescence measurements excluded the possibility of oxygen vacancy as the origin of the ferromagnetism.

  9. Room temperature ferromagnetism in a phthalocyanine based carbon material

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Z., E-mail: honda@fms.saitama-u.ac.jp; Sato, K.; Sakai, M.; Fukuda, T.; Kamata, N. [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Hagiwara, M.; Kida, T. [KYOKUGEN (Center for Quantum Science and Technology under Extreme Conditions), Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

    2014-02-07

    We report on a simple method to fabricate a magnetic carbon material that contains nitrogen-coordinated transition metals and has a large magnetic moment. Highly chlorinated iron phthalocyanine was used as building blocks and potassium as a coupling reagent to uniformly disperse nitrogen-coordinated iron atoms on the phthalocyanine based carbon material. The iron phthalocyanine based carbon material exhibits ferromagnetic properties at room temperature and the ferromagnetic phase transition occurs at T{sub c} = 490 ± 10 K. Transmission electron microscopy observation, X-ray diffraction analysis, and the temperature dependence of magnetization suggest that the phthalocyanine molecules form three-dimensional random networks in the iron phthalocyanine based carbon material.

  10. Towards room temperature, direct, solvent free synthesis of tetraborohydrides

    International Nuclear Information System (INIS)

    Remhof, A; Yan, Y; Friedrichs, O; Kim, J W; Mauron, Ph; Borgschulte, A; Züttel, A; Wallacher, D; Buchsteiner, A; Hoser, A; Oh, K H; Cho, Y W

    2012-01-01

    Due to their high hydrogen content, tetraborohydrides are discussed as potential synthetic energy carriers. On the example of lithium borohydride LiBH 4 , we discuss current approaches of direct, solvent free synthesis based on gas solid reactions of the elements or binary hydrides and/or borides with gaseous H 2 or B 2 H 6 . The direct synthesis from the elements requires high temperature and high pressure (700°C, 150bar D 2 ). Using LiB or AlB 2 as boron source reduces the required temperature by more than 300 K. Reactive milling of LiD with B 2 H 6 leads to the formation of LiBD 4 already at room temperature. The reactive milling technique can also be applied to synthesize other borohydrides from their respective metal hydrides.

  11. Ratcheting tests on stainless steel 316 L at room temperature

    International Nuclear Information System (INIS)

    Cousseran, Pierre; Lebey, Jacques; Roche, Roland; Corbel, P.

    1980-06-01

    An experimental study on progressive distortion (tension-torsion) of simple structures (thin tubes) has been undertaken at the CEA. Results of tests performed on 316 L steel at room temperature are reported in this paper. There are chiefly: - plastic iso-deformation curves in the field of the 2 loadings applied to the specimen, i.e. the constant primary loading P (tension) and the secondary loading ΔQ (cyclic torsion at controled deformation); - indications on the evolution of torque and of torsion plastic deformation, during the cycling; - a convenient rule for evaluation of the progressive distortion is proposed. It is based on the use of an effective stress Psub(eff), which is determined from the tensile characteristics of the material, of when creep occurs, from creep curves [fr

  12. Room-temperature ferromagnetism in cerium dioxide powders

    Energy Technology Data Exchange (ETDEWEB)

    Rakhmatullin, R. M., E-mail: rrakhmat@kpfu.ru; Pavlov, V. V.; Semashko, V. V.; Korableva, S. L. [Kazan Federal University, Institute of Physics (Russian Federation)

    2015-08-15

    Room-temperature ferromagnetism is detected in a CeO{sub 2} powder with a grain size of about 35 nm and a low (<0.1 at %) manganese and iron content. The ferromagnetism in a CeO{sub 2} sample with a submicron crystallite size and the same manganese and iron impurity content is lower than in the nanocrystalline sample by an order of magnitude. Apart from ferromagnetism, both samples exhibit EPR spectra of localized paramagnetic centers, the concentration of which is lower than 0.01 at %. A comparative analysis of these results shows that the F-center exchange (FCE) mechanism cannot cause ferromagnetism. This conclusion agrees with the charge-transfer ferromagnetism model proposed recently.

  13. Field Effect Devices Sensitive to CO at Room Temperature

    Directory of Open Access Journals (Sweden)

    Ricardo ARAG?N

    2014-10-01

    Full Text Available [5,10,15-Tris(2,6-dichlorophenylcorrolate] cobalt(III was used to chemisorb CO selectively, on the gap-gate of MOS capacitors and the state of charge monitored by voltage shifts of the photocurrent induced by pulsed illumination under constant D. C. bias, proportionally to CO concentration in air. Negative chemically induced charges at room temperature induce positive responses above and negative shifts below the threshold voltage, conforming to acceptor behavior, and the dynamic range (125 ppm is limited by the silicon doping concentration. The linear proportionality between CO concentration and surface charge (6.46[ppm.m2.µC-1] corresponds to the low concentration limit of the Langmuir isotherm. Sluggish CO desorption can be compensated by photo stimulation at 395 nm.

  14. Room temperature ferroelectricity in continuous croconic acid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xuanyuan; Lu, Haidong; Yin, Yuewei; Ahmadi, Zahra; Costa, Paulo S. [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Zhang, Xiaozhe [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Department of Physics, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, Xiao; Yu, Le; Cheng, Xuemei [Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010 (United States); DiChiara, Anthony D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Gruverman, Alexei, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu; Enders, Axel, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu; Xu, Xiaoshan, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States)

    2016-09-05

    Ferroelectricity at room temperature has been demonstrated in nanometer-thin quasi 2D croconic acid thin films, by the polarization hysteresis loop measurements in macroscopic capacitor geometry, along with observation and manipulation of the nanoscale domain structure by piezoresponse force microscopy. The fabrication of continuous thin films of the hydrogen-bonded croconic acid was achieved by the suppression of the thermal decomposition using low evaporation temperatures in high vacuum, combined with growth conditions far from thermal equilibrium. For nominal coverages ≥20 nm, quasi 2D and polycrystalline films, with an average grain size of 50–100 nm and 3.5 nm roughness, can be obtained. Spontaneous ferroelectric domain structures of the thin films have been observed and appear to correlate with the grain patterns. The application of this solvent-free growth protocol may be a key to the development of flexible organic ferroelectric thin films for electronic applications.

  15. Neurobehavioral approach for evaluation of office workers' productivity: The effects of room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Li; Lian, Zhiwei; Pan, Li [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Ye, Qian [Shanghai Research Institute of Building Science, Shanghai 200041 (China)

    2009-08-15

    Indoor environment quality has great influence on worker's productivity, and how to assess the effect of indoor environment on productivity remains to be the major challenge. A neurobehavioral approach was proposed for evaluation of office workers' productivity in this paper. The distinguishing characteristic of neurobehavioral approach is its emphasis on the identification and measurement of behavioral changes, for the influence of environment on brain functions manifests behaviorally. Therefore worker's productivity can be comprehensively evaluated by testing the neurobehavioral functions. Four neurobehavioral functions, including perception, learning and memory, thinking, and executive functions were measured with nine representative psychometric tests. The effect of room temperature on performance of neurobehavioral tests was investigated in the laboratory. Four temperatures (19 C, 24 C, 27 C, and 32 C) were investigated based on the thermal sensation from cold to hot. Signal detection theory was utilized to analyze response bias. It was found that motivated people could maintain high performance for a short time under adverse (hot or cold) environmental conditions. Room temperature affected task performance differentially, depending on the type of tasks. The proposed neurobehavioral approach could be worked to quantitatively and systematically evaluate office workers' productivity. (author)

  16. Stable room-temperature thallium bromide semiconductor radiation detectors

    Science.gov (United States)

    Datta, A.; Fiala, J.; Becla, P.; Motakef, Shariar

    2017-10-01

    Thallium bromide (TlBr) is a highly efficient ionic semiconductor with excellent radiation detection properties. However, at room temperature, TlBr devices polarize under an applied electric field. This phenomenon not only degrades the charge collection efficiency of the detectors but also promotes chemical reaction of the metal electrodes with bromine, resulting in an unstable electric field and premature failure of the device. This drawback has been crippling the TlBr semiconductor radiation detector technology over the past few decades. In this exhaustive study, this polarization phenomenon has been counteracted using innovative bias polarity switching schemes. Here the highly mobile Br- species, with an estimated electro-diffusion velocity of 10-8 cm/s, face opposing electro-migration forces during every polarity switch. This minimizes the device polarization and availability of Br- ions near the metal electrode. Our results indicate that it is possible to achieve longer device lifetimes spanning more than 17 000 h (five years of 8 × 7 operation) for planar and pixelated radiation detectors using this technique. On the other hand, at constant bias, 2500 h is the longest reported lifetime with most devices less than 1000 h. After testing several biasing switching schemes, it is concluded that the critical bias switching frequency at an applied bias of 1000 V/cm is about 17 μHz. Using this groundbreaking result, it will now be possible to deploy this highly efficient room temperature semiconductor material for field applications in homeland security, medical imaging, and physics research.

  17. Stable room-temperature thallium bromide semiconductor radiation detectors

    Directory of Open Access Journals (Sweden)

    A. Datta

    2017-10-01

    Full Text Available Thallium bromide (TlBr is a highly efficient ionic semiconductor with excellent radiation detection properties. However, at room temperature, TlBr devices polarize under an applied electric field. This phenomenon not only degrades the charge collection efficiency of the detectors but also promotes chemical reaction of the metal electrodes with bromine, resulting in an unstable electric field and premature failure of the device. This drawback has been crippling the TlBr semiconductor radiation detector technology over the past few decades. In this exhaustive study, this polarization phenomenon has been counteracted using innovative bias polarity switching schemes. Here the highly mobile Br− species, with an estimated electro-diffusion velocity of 10−8 cm/s, face opposing electro-migration forces during every polarity switch. This minimizes the device polarization and availability of Br− ions near the metal electrode. Our results indicate that it is possible to achieve longer device lifetimes spanning more than 17 000 h (five years of 8 × 7 operation for planar and pixelated radiation detectors using this technique. On the other hand, at constant bias, 2500 h is the longest reported lifetime with most devices less than 1000 h. After testing several biasing switching schemes, it is concluded that the critical bias switching frequency at an applied bias of 1000 V/cm is about 17 μHz. Using this groundbreaking result, it will now be possible to deploy this highly efficient room temperature semiconductor material for field applications in homeland security, medical imaging, and physics research.

  18. Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ravikumar, Patta; Kisan, Bhagaban; Perumal, A., E-mail: perumal@iitg.ernet.in [Department of Physics, Indian institute of Technology Guwahati, Guwahati 781 039 (India)

    2015-08-15

    We report systematic investigations of structural, vibrational, resonance and magnetic properties of nanoscale NiO powders prepared by ball milling process under different milling speeds for 30 hours of milling. Structural properties revealed that both pure NiO and as-milled NiO powders exhibit face centered cubic structure, but average crystallite size decreases to around 11 nm along with significant increase in strain with increasing milling speed. Vibrational properties show the enhancement in the intensity of one-phonon longitudinal optical (LO) band and disappearance of two-magnon band due to size reduction. In addition, two-phonon LO band exhibits red shift due to size-induced phonon confinement effect and surface relaxation. Pure NiO powder exhibit antiferromagnetic nature, which transforms into induced ferromagnetic after size reduction. The average magnetization at room temperature increases with decreasing the crystallite size and a maximum moment of 0.016 μ{sub B}/f.u. at 12 kOe applied field and coercivity of 170 Oe were obtained for 30 hours milled NiO powders at 600 rotation per minute milling speed. The change in the magnetic properties is also supported by the vibrational properties. Thermomagnetization measurements at high temperature reveal a well-defined magnetic phase transition at high temperature (T{sub C}) around 780 K due to induced ferromagnetic phase. Electron paramagnetic resonance (EPR) studies reveal a good agreement between the EPR results and magnetic properties. The observed results are described on the basis of crystallite size variation, defect density, large strain, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. The obtained results suggest that nanoscale NiO powders with high T{sub C} and moderate magnetic moment at room temperature with cubic structure would be useful to expedite for spintronic devices.

  19. Enhanced room temperature ferromagnetism in antiferromagnetic NiO nanoparticles

    Directory of Open Access Journals (Sweden)

    Patta Ravikumar

    2015-08-01

    Full Text Available We report systematic investigations of structural, vibrational, resonance and magnetic properties of nanoscale NiO powders prepared by ball milling process under different milling speeds for 30 hours of milling. Structural properties revealed that both pure NiO and as-milled NiO powders exhibit face centered cubic structure, but average crystallite size decreases to around 11 nm along with significant increase in strain with increasing milling speed. Vibrational properties show the enhancement in the intensity of one-phonon longitudinal optical (LO band and disappearance of two-magnon band due to size reduction. In addition, two-phonon LO band exhibits red shift due to size-induced phonon confinement effect and surface relaxation. Pure NiO powder exhibit antiferromagnetic nature, which transforms into induced ferromagnetic after size reduction. The average magnetization at room temperature increases with decreasing the crystallite size and a maximum moment of 0.016 μB/f.u. at 12 kOe applied field and coercivity of 170 Oe were obtained for 30 hours milled NiO powders at 600 rotation per minute milling speed. The change in the magnetic properties is also supported by the vibrational properties. Thermomagnetization measurements at high temperature reveal a well-defined magnetic phase transition at high temperature (TC around 780 K due to induced ferromagnetic phase. Electron paramagnetic resonance (EPR studies reveal a good agreement between the EPR results and magnetic properties. The observed results are described on the basis of crystallite size variation, defect density, large strain, oxidation/reduction of Ni and interaction between uncompensated surfaces and particle core with lattice expansion. The obtained results suggest that nanoscale NiO powders with high TC and moderate magnetic moment at room temperature with cubic structure would be useful to expedite for spintronic devices.

  20. Immobilization of Ag(i) into a metal-organic framework with -SO3H sites for highly selective olefin-paraffin separation at room temperature.

    Science.gov (United States)

    Chang, Ganggang; Huang, Minhui; Su, Ye; Xing, Huabin; Su, Baogen; Zhang, Zhiguo; Yang, Qiwei; Yang, Yiwen; Ren, Qilong; Bao, Zongbi; Chen, Banglin

    2015-02-18

    Introduction of Ag(i) ions into a sulfonic acid functionalized MOF ((Cr)-MIL-101-SO3H) significantly enhances its interactions with olefin double bonds, leading to its much higher selectivities for the separation of C2H4-C2H6 and C3H6-C3H8 at room temperature over the original (Cr)-MIL-101-SO3H and other adsorbents at room temperature.

  1. Nuclear Fuel Fretting Mechanisms in a Room Temperature Unlubricated Condition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Ho; Kim, Hyung Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    Recently, efforts for evaluating the fretting wear mechanism have been carried out by many researchers in various conditions. In an unlubricated condition, especially, effects of a wear debris and/or its layer on the fretting wear behavior were proposed that the formation of a well-developed glaze layer has a beneficial effect for decreasing a friction coefficient. Otherwise, a wear rate was accelerated by a third-body abrasion. At this time, it is well known that wear debris behaviors are affected by test variables such as a temperature, environment, material characteristics, etc. In a nuclear fuel fretting, however, its contact condition is quite different when compared with general fretting wear studies and could be summarized as the following; first, a fuel rod is supported by spacer grid springs and dimples that were elastically deformable. This results in a unique friction loop and a different fretting mechanism when a fuel rod is vibrated due to a flow-induced vibration (FIV). Next, it is possible that some region of the wear scar area with a specific spring shape condition could be hidden due to different wear debris behavior. So, some of the wear debris layers could be found on the worn surfaces in previous studies even though fretting wear tests were performed in a water lubricated condition. Finally, initial contact condition could be changed both an actual operating condition in power plants (i.e. high temperature and pressurized water (HTHP) under severe irradiation conditions) and the fretting wear tests for evaluating the wear resistant spring in lab conditions (i.e. from room temperature to HTHP without irradiation conditions) due to material degradations and the formation of the wear scar, respectively. In summary, the spring shape effect and the variation of the contact condition with increasing fretting cycle should be evaluated in order to improve the wear resistance of the spacer grid spring. So, in this study, fretting wear tests have been

  2. Room temperature d (0) ferromagnetism in hole doped Y2O3: widening the choice of host to tailor DMS.

    Science.gov (United States)

    Chakraborty, Brahmananda; Ramaniah, Lavanya M

    2016-08-24

    Transition metal-free-ferromagnetism in diluted magnetic semiconductors (DMS) is of much current interest in view of the search for more efficient DMS materials for spintronics applications. Our DFT results predict for the first time, that impurities from group1A (Li(+), Na(+), K(+)) doped on Y2O3 can induce a magnetic signature with a magnetic moment around 2.0 μ B per defect at hole concentrations around 1.63  ×  10(21) cm(-3), which is one order less than the critical hole density of ZnO with ferromagnetic coupling large enough to promote room temperature ferromagnetism. The induction of room temperature ferromagnetism by hole doping with an impurity atom from group 1A, which injects two holes per defect in the system, implies that the recommendation of three holes per defect given in the literature, which puts a restriction on the choice of host material and the impurity, is not a necessary criterion for hole induced room temperature ferromagnetism. DFT simulations with the generalized gradient approximation (GGA), confirmed by the more sophisticated hybrid functional, Heyd-Scuseria-Ernzerhof (HSE06), predict that the magnetic moment is mostly contributed by O atoms surrounding the impurity atom and the magnetic moment scale up with impurity concentration which is a positive indicator for practical applications. We quantitatively and extensively demonstrate through the analysis of the density of states and ferromagnetic coupling that the Stoner criterion is satisfied by pushing the Fermi level inside the valence band to activate room temperature ferromagnetism. The stability of the structure and the persistence of ferromagnetism at room temperature were demonstrated by ab initio MD simulations and computation of Curie temperature through the mean field approximation. This study widens the choice of host oxides to tailor DMS for spintronics applications.

  3. A functional F analogue of AcMNPV GP64 is from the Agrotis segetum granulovirus

    NARCIS (Netherlands)

    Yin, F.; Wang, M.; Tan, Y.; Deng, F.; Vlak, J.M.; Hu, Z.H.; Wang, H.

    2008-01-01

    The envelope fusion protein F of Plutella xylostella granulovirus is a computational analogue of the GP64 envelope fusion protein of Autographa californica nucleopolyhedrovirus (AcMNPV). Granulovirus (GV) F proteins were thought to be unable to functionally replace GP64 in the AcMNPV pseudotyping

  4. Lead palladium titanate: A room-temperature multiferroic

    Science.gov (United States)

    Gradauskaite, Elzbieta; Gardner, Jonathan; Smith, Rebecca M.; Morrison, Finlay D.; Lee, Stephen L.; Katiyar, Ram S.; Scott, James F.

    2017-09-01

    There have been a large number of papers on bismuth ferrite (BiFe O3 ) over the past few years, trying to exploit its room-temperature magnetoelectric multiferroic properties. Although these are attractive, BiFe O3 is not the ideal multiferroic due to weak magnetization and the difficulty in limiting leakage currents. Thus there is an ongoing search for alternatives, including such materials as gallium ferrite (GaFe O3 ). In the present work we report a comprehensive study of the perovskite PbT i1 -xP dxO3 with 0

  5. All-Aluminum Thin Film Transistor Fabrication at Room Temperature

    Directory of Open Access Journals (Sweden)

    Rihui Yao

    2017-02-01

    Full Text Available Bottom-gate all-aluminum thin film transistors with multi conductor/insulator nanometer heterojunction were investigated in this article. Alumina (Al2O3 insulating layer was deposited on the surface of aluminum doping zinc oxide (AZO conductive layer, as one AZO/Al2O3 heterojunction unit. The measurements of transmittance electronic microscopy (TEM and X-ray reflectivity (XRR revealed the smooth interfaces between ~2.2-nm-thick Al2O3 layers and ~2.7-nm-thick AZO layers. The devices were entirely composited by aluminiferous materials, that is, their gate and source/drain electrodes were respectively fabricated by aluminum neodymium alloy (Al:Nd and pure Al, with Al2O3/AZO multilayered channel and AlOx:Nd gate dielectric layer. As a result, the all-aluminum TFT with two Al2O3/AZO heterojunction units exhibited a mobility of 2.47 cm2/V·s and an Ion/Ioff ratio of 106. All processes were carried out at room temperature, which created new possibilities for green displays industry by allowing for the devices fabricated on plastic-like substrates or papers, mainly using no toxic/rare materials.

  6. Room-temperature ballistic transport in III-nitride heterostructures.

    Science.gov (United States)

    Matioli, Elison; Palacios, Tomás

    2015-02-11

    Room-temperature (RT) ballistic transport of electrons is experimentally observed and theoretically investigated in III-nitrides. This has been largely investigated at low temperatures in low band gap III-V materials due to their high electron mobilities. However, their application to RT ballistic devices is limited by their low optical phonon energies, close to KT at 300 K. In addition, the short electron mean-free-path at RT requires nanoscale devices for which surface effects are a limitation in these materials. We explore the unique properties of wide band-gap III-nitride semiconductors to demonstrate RT ballistic devices. A theoretical model is proposed to corroborate experimentally their optical phonon energy of 92 meV, which is ∼4× larger than in other III-V semiconductors. This allows RT ballistic devices operating at larger voltages and currents. An additional model is described to determine experimentally a characteristic dimension for ballistic transport of 188 nm. Another remarkable property is their short carrier depletion at device sidewalls, down to 13 nm, which allows top-down nanofabrication of very narrow ballistic devices. These results open a wealth of new systems and basic transport studies possible at RT.

  7. “A Long March to Room Temperature Superconductivity”

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    In the last 29 years, great progress has been made in all areas of high temperature superconductivity (HTS) research from raising the transition temperature Tc and discovering new HTS compounds to developing theoretical models of HTS and fabricating and testing HTS prototype devices. For example, the Tc has been increased to 164 K in cuprate HgBa2Ca2Cu3Ox under 30 GPa in 1993 at Houston, more than 200 HTS compounds have been found, numerous theoretical models have been developed, and many HTS prototype devices have been tested to display superior performance to that of their non-superconducting counterparts. The strong electron-phonon interaction required for the high Tc observed has been considered to be able to induce catastrophic structure collapse before high Tc can be realized, and a novel magnetism-based interaction in different forms has thus been proposed for high Tc. However, room temperature superconductivity is still elusive and a comprehensive microscopic theory of HTS remains to be achieved. The...

  8. Ratcheting fatigue behavior of Zircaloy-2 at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rajpurohit, R.S., E-mail: rsrajpurohit.rs.met13@iitbhu.ac.in [Department of Metallurgical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi, 221005 (India); Sudhakar Rao, G. [Nuclear Energy and Safety Department, Paul Scherrer Institute, Villigen, CH-5232 (Switzerland); Chattopadhyay, K.; Santhi Srinivas, N.C.; Singh, Vakil [Department of Metallurgical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi, 221005 (India)

    2016-08-15

    Nuclear core components of zirconium alloys experience asymmetric stress or strain cycling during service which leads to plastic strain accumulation and drastic reduction in fatigue life as well as dimensional instability of the component. Variables like loading rate, mean stress, and stress amplitude affect the influence of asymmetric loading. In the present investigation asymmetric stress controlled fatigue tests were conducted with mean stress from 80 to 150 MPa, stress amplitude from 270 to 340 MPa and stress rate from 30 to 750 MPa/s to study the process of plastic strain accumulation and its effect on fatigue life of Zircaloy-2 at room temperature. It was observed that with increase in mean stress and stress amplitude accumulation of ratcheting strain was increased and fatigue life was reduced. However, increase in stress rate led to improvement in fatigue life due to less accumulation of ratcheting strain. - Highlights: • Ratcheting strain accumulation occurred due to asymmetric cyclic loading. • Accumulation of ratcheting strain increased with mean stress and stress amplitude. • Ratcheting strain accumulation decreased with increase in stress rate. • With increase in mean stress and stress amplitude there was reduction in fatigue life. • Fatigue life is improved with increase in stress rate.

  9. Proactive aquatic ecotoxicological assessment of room-temperature ionic liquids

    Science.gov (United States)

    Kulacki, K.J.; Chaloner, D.T.; Larson, J.H.; Costello, D.M.; Evans-White, M. A.; Docherty, K.M.; Bernot, R.J.; Brueseke, M.A.; Kulpa, C.F.; Lamberti, G.A.

    2011-01-01

    Aquatic environments are being contaminated with a myriad of anthropogenic chemicals, a problem likely to continue due to both unintentional and intentional releases. To protect valuable natural resources, novel chemicals should be shown to be environmentally safe prior to use and potential release into the environment. Such proactive assessment is currently being applied to room-temperature ionic liquids (ILs). Because most ILs are water-soluble, their effects are likely to manifest in aquatic ecosystems. Information on the impacts of ILs on numerous aquatic organisms, focused primarily on acute LC50 and EC50 endpoints, is now available, and trends in toxicity are emerging. Cation structure tends to influence IL toxicity more so than anion structure, and within a cation class, the length of alkyl chain substituents is positively correlated with toxicity. While the effects of ILs on several aquatic organisms have been studied, the challenge for aquatic toxicology is now to predict the effects of ILs in complex natural environments that often include diverse mixtures of organisms, abiotic conditions, and additional stressors. To make robust predictions about ILs will require coupling of ecologically realistic laboratory and field experiments with standard toxicity bioassays and models. Such assessments would likely discourage the development of especially toxic ILs while shifting focus to those that are more environmentally benign. Understanding the broader ecological effects of emerging chemicals, incorporating that information into predictive models, and conveying the conclusions to those who develop, regulate, and use those chemicals, should help avoid future environmental degradation. ?? 2011 Bentham Science Publishers Ltd.

  10. Room-temperature ferromagnetism in hydrogenated ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Xudong; Liu, Liangliang; Wang, Zhu; Wu, Yichu, E-mail: ycwu@whu.edu.cn [School of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory, Wuhan University, Wuhan 430072 (China)

    2014-01-21

    The effect of hydrogen doping on the magnetic properties of ZnO nanoparticles was investigated. Hydrogen was incorporated by annealing under 5% H{sub 2} in Ar ambient at 700 °C. Room-temperature ferromagnetism was induced in hydrogenated ZnO nanoparticles, and the observed ferromagnetism could be switched between “on” and “off” states through hydrogen annealing and oxygen annealing process, respectively. It was found that Zn vacancy and OH bonding complex (V{sub Zn} + OH) was crucial to the observed ferromagnetism by using the X-ray photoelectron spectroscopy and positron annihilation spectroscopy analysis. Based on first-principles calculations, V{sub Zn} + OH was favorable to be presented due to the low formation energy. Meanwhile, this configuration could lead to a magnetic moment of 0.57 μ{sub B}. The Raman and photoluminescence measurements excluded the possibility of oxygen vacancy as the origin of the ferromagnetism.

  11. Cyclic deformation of zircaloy-4 at room temperature

    International Nuclear Information System (INIS)

    Armas, A. F; Herenu, S; Bolmaro, R; Alvarez-Armas, I

    2003-01-01

    Annealed materials hardens under low cyclic fatigue tests.However, FCC metals tested with medium strain amplitudes show an initial cyclic softening.That behaviour is related with the strong interstitial atom-dislocation interactions.For HCP materials the information is scarce.Commercial purity Zirconium and Zircaloy-4 alloys show also a pronounced cyclic softening, similar to Titanium alloys.Recently the rotation texture induced softening model has been proposed according to which the crystals are placed in a more favourable deformation orientation by prismatic slip due to the cyclic strain.The purpose of the current paper is the presentation of decisive results to discuss the causes for cyclic softening of Zircaloy-4. Low cycle fatigue tests were performed on recrystallized Zircaloy-4 samples.The cyclic behaviour shows an exponential softening at room temperature independently of the deformation range.Only at high temperature a cyclic hardening is shown at low number of cycles.Friction stresses, related with dislocation movement itself, and back stresses, related with dislocation pile-ups can be calculated from the stress-strain loops.The cyclic softening is due to diminishing friction stress while the starting hardening behaviour is due to increasing back stresses.The rotation texture induced softening model is ruled out assuming instead a model based on dislocation unlocking from interstitial oxygen solute atoms

  12. A room-temperature liquid calorimeter prototype for the SSC

    International Nuclear Information System (INIS)

    Brandenburg, G.W.; Geer, S.H.; Oliver, J.; Sadowski, E.; Theriot, D.

    1990-01-01

    Calorimeters will be an extremely important part of SSC detectors as they have been in existing collider detectors. The main issues that need to be addressed are: (1) energy resolution of jets and electrons, (2) segmentation, (3) hermiticity, (4) response time, and (5) radiation resistance. An attractive possibility on all these counts is the use of room-temperature liquids together with uranium, as pioneered by UA1. The authors are planning a prototype calorimeter which consists of a sealed vessel containing both the radiator plates and the readout pads. This geometry has been appropriately named the swimming pool design. The general mechanical starting point is similar to the SLD liquid argon calorimeters. The points they wish to address are the following: (1) Simple and reliable modular construction techniques, (2) Satisfactory electrical connections with minimal geometric impact, (3) The necessity of isolating radiator plates and liquid to maintain purity, (4) What materials can be immersed without compromising the liquid purity. The design and construction of the swimming pool electromagnetic calorimeter prototype is being carried out at the Harvard High Energy Physics Laboratory. This is one of the first attempts to build a full-scale prototype of such a design

  13. Boron lattice location in room temperature ion implanted Si crystal

    International Nuclear Information System (INIS)

    Piro, A.M.; Romano, L.; Mirabella, S.; Grimaldi, M.G.

    2005-01-01

    The B lattice location in presence of a Si-self-interstitial (I Si ) supersaturation, controlled by energetic proton bombardment, has been studied by means of ion channelling and massive Monte Carlo simulations. B-doped layers of Si crystals with a B concentration of 1 x 10 2 B/cm 3 were grown by Molecular Beam Epitaxy. Point defect engineering techniques, with light energetic ion implants, have been applied to generate an I Si uniform injection in the electrically active layer. The displacement of B atoms out of substitutional lattice sites was induced by 650 keV proton irradiations at room temperature (R.T.) and the resultant defect configuration was investigated by ion channelling and Nuclear Reaction Analysis (NRA) techniques. Angular scans were measured both through and axes along the (1 0 0) plane using the 11 B(p,α) 8 Be nuclear reaction at 650 keV proton energy. Monte Carlo simulated angular scans were calculated considering a variety of theoretical defect configurations, supported by literature, and compared with experimental data. Our experimental scans can be fitted by a linear combination of small (0.3 A) and large B displacements (1.25 A) along the direction, compatible with the B-dumbbell oriented along as proposed by ab initio calculations

  14. Behavior of porous tungsten under shock compression at room temperature

    International Nuclear Information System (INIS)

    Dandekar, D.P.; Lamothe, R.M.

    1977-01-01

    This work reports the results of room-temperature shock-compression experiments on porous tungsten. The porous tungsten was fabricated by sintering 1-μm tungsten particles. The initial density of the material was 15290 kg/m 3 . Around 97% of the pores in the material were interconnected. The main features of the results are as follows: (1) porous tungsten behaves as a linear elastic material to 1.43 GPa; (2) the shock wave following the elastic precursor is unstable in the material in the stress range 1.43--2.7 GPa; (3) a stable two-wave structure is established at and above 6.4 GPa; (4) the response of porous tungsten is accurately described by the Mie-Grueneisen equation of state at stresses above 4.9 GPa, the stress at which the voids suffer a complete extinction in the material; (5) the deformations induced in the material due to shock compression are irreversible; (6) the recentered Hugoniot of porous tungsten becomes stiffer with the increasing magnitude of initial compressive stress

  15. Above-room-temperature ferroelectricity and antiferroelectricity in benzimidazoles

    Science.gov (United States)

    Horiuchi, Sachio; Kagawa, Fumitaka; Hatahara, Kensuke; Kobayashi, Kensuke; Kumai, Reiji; Murakami, Youichi; Tokura, Yoshinori

    2012-12-01

    The imidazole unit is chemically stable and ubiquitous in biological systems; its proton donor and acceptor moieties easily bind molecules into a dipolar chain. Here we demonstrate that chains of these amphoteric molecules can often be bistable in electric polarity and electrically switchable, even in the crystalline state, through proton tautomerization. Polarization-electric field (P-E) hysteresis experiments reveal a high electric polarization ranging from 5 to 10 μC cm-2 at room temperature. Of these molecules, 2-methylbenzimidazole allows ferroelectric switching in two dimensions due to its pseudo-tetragonal crystal symmetry. The ferroelectricity is also thermally robust up to 400 K, as is that of 5,6-dichloro-2-methylbenzimidazole (up to ~373 K). In contrast, three other benzimidazoles exhibit double P-E hysteresis curves characteristic of antiferroelectricity. The diversity of imidazole substituents is likely to stimulate a systematic exploration of various structure-property relationships and domain engineering in the quest for lead- and rare-metal-free ferroelectric devices.

  16. Rf breakdown studies in room temperature electron linac structures

    International Nuclear Information System (INIS)

    Loew, G.A.; Wang, J.W.

    1988-05-01

    This paper is an overall review of studies carried out by the authors and some of their colleagues on RF breakdown, Field Emission and RF processing in room temperature electron linac structure. The motivation behind this work is twofold: in a fundamental way, to contribute to the understanding of the RF breakdown phenomenon, and as an application, to determine the maximum electric field gradient that can be obtained and used safely in future e/sup +-/ linear colliders. Indeed, the next generation of these machines will have to reach into the TeV (10 12 eV) energy range, and the accelerating gradient will be to be of the crucial parameters affecting their design, construction and cost. For a specified total energy, the gradient sets the accelerator length, and once the RF structure, frequency and pulse repetition rate are selected, it also determines the peak and average power consumption. These three quantities are at the heart of the ultimate realizability and cost of these accelerators. 24 refs., 19 figs., 4 tabs

  17. A computed room temperature line list for phosphine

    Science.gov (United States)

    Sousa-Silva, Clara; Yurchenko, Sergei N.; Tennyson, Jonathan

    2013-06-01

    An accurate and comprehensive room temperature rotation-vibration transition line list for phosphine (31PH3) is computed using a newly refined potential energy surface and a previously constructed ab initio electric dipole moment surface. Energy levels, Einstein A coefficients and transition intensities are computed using these surfaces and a variational approach to the nuclear motion problem as implemented in the program TROVE. A ro-vibrational spectrum is computed, covering the wavenumber range 0-8000 cm-1. The resulting line list, which is appropriate for temperatures up to 300 K, consists of a total of 137 million transitions between 5.6 million energy levels. Several of the band centres are shifted to better match experimental transition frequencies. The line list is compared to the most recent HITRAN database and other laboratorial sources. Transition wavelengths and intensities are generally found to be in good agreement with the existing experimental data, with particularly close agreement for the rotational spectrum. An analysis of the comparison between the theoretical data created and the existing experimental data is performed, and suggestions for future improvements and assignments to the HITRAN database are made.

  18. Room temperature Zinc-metallation of cationic porphyrin at graphene surface and enhanced photoelectrocatalytic activity

    Science.gov (United States)

    Zeng, Rongjin; Chen, Guoliang; Xiong, Chungang; Li, Gengxian; Zheng, Yinzhi; Chen, Jian; Long, Yunfei; Chen, Shu

    2018-03-01

    A stable zincporphyrin functionalized graphene nanocomposite was prepared by using positively charged cationic porphyrin (5,10,15,20-tetra(4-propyl pyridinio) porphyrin, TPPyP) and successive reduced graphene oxide (rGO) with tuned negative charge. The nanocomposite preparation was accompanied first by distinct electrostatic interactions and π-π stacking between TPPyP and rGO, and followed by fast Zinc-metallation at room temperature. In contrast to free TPPyP with Zn2+, the incorporation reaction is very slow at room temperature and heating or reflux conditions are required to increase the metallation rate. While at the surface of rGO nanosheet, the Zinc-metallation of TPPyP was greatly accelerated to 30 min at 25 °C in aqueous solution. The interaction process and composites formation were fully revealed by significant variations in UV-vis absorption spectra, X-ray photoelectron spectra (XPS) measurements, atomic force microscope (AFM) images, and fluorescence spectra. Furthermore, photoelectrochemical activity of resultant rGO/TPPyP-Zn nanocomposites was evaluated under visible-light irradiation, and enhancement of the photoelectrocatalytic reduction of CO2 was achieved.

  19. Room temperature continuous wave mid-infrared VCSEL operating at 3.35 μm

    Science.gov (United States)

    Jayaraman, V.; Segal, S.; Lascola, K.; Burgner, C.; Towner, F.; Cazabat, A.; Cole, G. D.; Follman, D.; Heu, P.; Deutsch, C.

    2018-02-01

    Tunable vertical cavity surface emitting lasers (VCSELs) offer a potentially low cost tunable optical source in the 3-5 μm range that will enable commercial spectroscopic sensing of numerous environmentally and industrially important gases including methane, ethane, nitrous oxide, and carbon monoxide. Thus far, achieving room temperature continuous wave (RTCW) VCSEL operation at wavelengths beyond 3 μm has remained an elusive goal. In this paper, we introduce a new device structure that has enabled RTCW VCSEL operation near the methane absorption lines at 3.35 μm. This device structure employs two GaAs/AlGaAs mirrors wafer-bonded to an optically pumped active region comprising compressively strained type-I InGaAsSb quantum wells grown on a GaSb substrate. This substrate is removed in processing, as is one of the GaAs mirror substrates. The VCSEL structure is optically pumped at room temperature with a CW 1550 nm laser through the GaAs substrate, while the emitted 3.3 μm light is captured out of the top of the device. Power and spectrum shape measured as a function of pump power exhibit clear threshold behavior and robust singlemode spectra.

  20. Self-assembly of gas-phase synthesized magnesium nanoparticles on room temperature substrates

    International Nuclear Information System (INIS)

    Venturi, F; Calizzi, M; Pasquini, L; Bals, S; Perkisas, T

    2015-01-01

    Magnesium nanoparticles (NPs) with initial size in the 10–50 nm range were synthesized by inert gas condensation under helium flow and deposited on room temperature substrates. The morphology and crystal structure of the NPs ensemble were investigated as a function of the deposition time by complementary electron microscopy techniques, including high resolution imaging and chemical mapping. With increasing amount of material, strong coarsening phenomena were observed at room temperature: small NPs disappeared while large faceted NPs developed, leading to a 5-fold increase of the average NPs size within a few minutes. The extent of coarsening and the final morphology depended also on the nature of the substrate. Furthermore, large single-crystal NPs were seen to arise from the self-organization of primary NPs units, providing a mechanism for crystal growth. The dynamics of the self-assembly process involves the basic steps of NPs sticking, diffusion on substrate, coordinated rotation and attachment/coalescence. Key features are the surface energy anisotropy, reflected by the faceted shape of the NPs, and the low melting point of the material. The observed phenomena have strong implications in relation to the synthesis and stability of nanostructures based on Mg or other elements with similar features. (paper)

  1. Branched carbon nanofiber network synthesis at room temperature using radio frequency supported microwave plasmas

    OpenAIRE

    Boskovic, BO; Stolojan, V; Zeze, DA; Forrest, RD; Silva, SRP; Haq, S

    2004-01-01

    Carbon nanofibers have been grown at room temperature using a combination of radio frequency and microwave assisted plasma-enhanced chemical vapor deposition. The nanofibers were grown, using Ni powder catalyst, onto substrates kept at room temperature by using a purposely designed water-cooled sample holder. Branched carbon nanofiber growth was obtained without using a template resulting in interconnected carbon nanofiber network formation on substrates held at room temperatur...

  2. Room-temperature macromolecular serial crystallography using synchrotron radiation

    Directory of Open Access Journals (Sweden)

    Francesco Stellato

    2014-07-01

    Full Text Available A new approach for collecting data from many hundreds of thousands of microcrystals using X-ray pulses from a free-electron laser has recently been developed. Referred to as serial crystallography, diffraction patterns are recorded at a constant rate as a suspension of protein crystals flows across the path of an X-ray beam. Events that by chance contain single-crystal diffraction patterns are retained, then indexed and merged to form a three-dimensional set of reflection intensities for structure determination. This approach relies upon several innovations: an intense X-ray beam; a fast detector system; a means to rapidly flow a suspension of crystals across the X-ray beam; and the computational infrastructure to process the large volume of data. Originally conceived for radiation-damage-free measurements with ultrafast X-ray pulses, the same methods can be employed with synchrotron radiation. As in powder diffraction, the averaging of thousands of observations per Bragg peak may improve the ratio of signal to noise of low-dose exposures. Here, it is shown that this paradigm can be implemented for room-temperature data collection using synchrotron radiation and exposure times of less than 3 ms. Using lysozyme microcrystals as a model system, over 40 000 single-crystal diffraction patterns were obtained and merged to produce a structural model that could be refined to 2.1 Å resolution. The resulting electron density is in excellent agreement with that obtained using standard X-ray data collection techniques. With further improvements the method is well suited for even shorter exposures at future and upgraded synchrotron radiation facilities that may deliver beams with 1000 times higher brightness than they currently produce.

  3. Trends in the design of front-end systems for room temperature solid state detectors

    International Nuclear Information System (INIS)

    Manfredi, Pier F.; Re, Valerio

    2003-01-01

    The paper discusses the present trends in the design of low-noise front-end systems for room temperature semiconductor detectors. The technological advancement provided by submicron CMOS and BiCMOS processes is examined from several points of view. The noise performances are a fundamental issue in most detector applications and suitable attention is devoted to them for the purpose of judging whether or not the present processes supersede the solutions featuring a field-effect transistor as a front-end element. However, other considerations are also important in judging how well a monolithic technology suits the front-end design. Among them, the way a technology lends itself to the realization of additional functions, for instance, the charge reset in a charge-sensitive loop or the time-variant filters featuring the special weighting functions that may be requested in some applications of CdTe or CZT detectors

  4. Scaling of dynamical decoupling for a single electron spin in nanodiamonds at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong-Qi; Liu, Gang-Qin; Chang, Yan-Chun; Pan, Xin-Yu, E-mail: xypan@aphy.iphy.ac.cn

    2014-01-01

    Overcoming the spin qubit decoherence is a challenge for quantum science and technology. We investigate the decoherence process in nanodiamonds by Carr–Purcell–Meiboom–Gill (CPMG) technique at room temperature. We find that the coherence time T{sub 2} scales as n{sup γ}. The elongation effect of coherence time can be represented by a constant power of the number of pulses n. Considering the filter function of CPMG decoupling sequence as a δ function, the spectrum density of noise has been reconstructed directly from the coherence time measurements and a Lorentzian noise power spectrum model agrees well with the experiment. These results are helpful for the application of nanodiamonds to nanoscale magnetic imaging.

  5. Dipolar molecules inside C-70: an electric field-driven room-temperature single-molecule switch

    Czech Academy of Sciences Publication Activity Database

    Foroutan-Nejad, C.; Andrushchenko, Valery; Straka, Michal

    2016-01-01

    Roč. 18, č. 48 (2016), s. 32673-32677 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA14-03564S Institutional support: RVO:61388963 Keywords : room-temperature single-molecule switch * electric field * endohedral fullerene * density functional calculations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.123, year: 2016 http://pubs.rsc.org/en/content/articlepdf/2016/cp/c6cp06986j

  6. Nanostructured ‘Anastacia’ flowers for Zn coating by electrodepositing ZnO at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Marta M., E-mail: martamalves@tecnico.ulisboa.pt [ICEMS Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001, Lisboa (Portugal); Santos, Catarina F.; Carmezim, Maria J. [ICEMS Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001, Lisboa (Portugal); EST Setúbal, DEM, Instituto Politécnico de Setúbal, Campus IPS, 2910 Setúbal (Portugal); Montemor, Maria F. [ICEMS Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001, Lisboa (Portugal)

    2015-03-30

    Graphical abstract: - Highlights: • Functional coating of Zn with ZnO ‘Anastacia’ flowers. • Flowers are composed by nano-hexagonal units of single-crystal wurtzite ZnO. • The growth mechanism of these flowers is discussed. • Room temperature yield cost-effective electrodeposited ZnO ‘Anastacia’ flowers. - Abstract: Functional coatings composed of ZnO, a new flowered structured denominated as ‘Anastacia’ flowers, were successfully obtained through a facile and green one-step electrodeposition approach on Zn substrate. Electrodeposition was performed at constant cathodic potential, in Zn(NO{sub 3}){sub 2} aqueous solution, at pH 6 and at room temperature. The resulting ZnO thin uniform layer, with an average thickness of 300 nm, bearing top 3D hierarchical nanostructures that compose ‘Anastacia’ flowers, was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman. The results reveal a nano-architecture structure composed by nano-hexagonal units of single-crystal wurtzite ZnO structure with a [0 0 0 1] growth direction along the longitudinal particles axis. Other morphological features, sphere-like, rod-like and random distributed hexagons were also obtained by varying the electrodeposition time as observed by SEM. The Raman spectroscopy revealed the typical peak of ZnO wurtzite for all the obtained morphologies. Coatings wettability was studied and the different morphologies display distinct water contact angles with the ‘Anastacia’ flowers coating showing a wettability of 110°. These results pave the way for simple and low-cost routes for the production of novel functionalized coatings of ZnO over Zn, with potential for biomedical devices.

  7. Nanostructured ‘Anastacia’ flowers for Zn coating by electrodepositing ZnO at room temperature

    International Nuclear Information System (INIS)

    Alves, Marta M.; Santos, Catarina F.; Carmezim, Maria J.; Montemor, Maria F.

    2015-01-01

    Graphical abstract: - Highlights: • Functional coating of Zn with ZnO ‘Anastacia’ flowers. • Flowers are composed by nano-hexagonal units of single-crystal wurtzite ZnO. • The growth mechanism of these flowers is discussed. • Room temperature yield cost-effective electrodeposited ZnO ‘Anastacia’ flowers. - Abstract: Functional coatings composed of ZnO, a new flowered structured denominated as ‘Anastacia’ flowers, were successfully obtained through a facile and green one-step electrodeposition approach on Zn substrate. Electrodeposition was performed at constant cathodic potential, in Zn(NO 3 ) 2 aqueous solution, at pH 6 and at room temperature. The resulting ZnO thin uniform layer, with an average thickness of 300 nm, bearing top 3D hierarchical nanostructures that compose ‘Anastacia’ flowers, was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman. The results reveal a nano-architecture structure composed by nano-hexagonal units of single-crystal wurtzite ZnO structure with a [0 0 0 1] growth direction along the longitudinal particles axis. Other morphological features, sphere-like, rod-like and random distributed hexagons were also obtained by varying the electrodeposition time as observed by SEM. The Raman spectroscopy revealed the typical peak of ZnO wurtzite for all the obtained morphologies. Coatings wettability was studied and the different morphologies display distinct water contact angles with the ‘Anastacia’ flowers coating showing a wettability of 110°. These results pave the way for simple and low-cost routes for the production of novel functionalized coatings of ZnO over Zn, with potential for biomedical devices

  8. The influence of room temperature on Mg isotope measurements by MC-ICP-MS.

    Science.gov (United States)

    Zhang, Xing-Chao; Zhang, An-Yu; Zhang, Zhao-Feng; Huang, Fang; Yu, Hui-Min

    2018-03-24

    We observed that the accuracy and precision of magnesium (Mg) isotope analyses could be affected if the room temperature oscillated during measurements. To achieve high quality Mg isotopic data, it is critical to evaluate how the unstable room temperature affects Mg isotope measurements by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). We measured the Mg isotopes for the reference material DSM-3 using MC-ICP-MS under oscillating room temperatures in spring. For a comparison, we also measured the Mg isotopes under stable room temperatures, which was achieved by the installation of an improved temperature control system in the laboratory. The δ 26 Mg values measured under oscillating room temperatures have a larger deviation (δ 26 Mg from -0.09 to 0.08‰, with average δ 26 Mg = 0.00 ± 0.08 ‰) than those measured under a stable room temperature (δ 26 Mg from -0.03 to 0.03‰, with average δ 26 Mg = 0.00 ± 0.02 ‰) using the same MC-ICP-MS system. The room temperature variation can influence the stability of MC-ICP-MS. Therefore, it is critical to keep the room temperature stable to acquire high precise and accurate isotopic data when using MC-ICP-MS, especially when using the sample-standard bracketing (SSB) correction method. This article is protected by copyright. All rights reserved.

  9. A Sleeping Beauty DNA transposon-based genetic sensor for functional screening of vitamin D3 analogues

    DEFF Research Database (Denmark)

    Staunstrup, Nicklas Heine; Sharma, Nynne; Bak, Rasmus Otkjær

    2011-01-01

    Analogues of vitamin D3 are extensively used in the treatment of various illnesses, such as osteoporosis, inflammatory skin diseases, and cancer. Functional testing of new vitamin D3 analogues and formulations for improved systemic and topical administration is supported by sensitive screening me...

  10. Colloquium: High pressure and road to room temperature superconductivity

    Science.gov (United States)

    Gor'kov, Lev P.; Kresin, Vladimir Z.

    2018-01-01

    future use of tunneling spectroscopy. This feature leads to nonmonotonic and strongly asymmetric pressure dependence of Tc . Other hydrides, e.g., CaH6 and MgH6 , can be expected to display even higher values of Tc up to room temperature. The fundamental challenge lies in the creation of a structure capable of displaying high Tc at ambient pressure.

  11. Growth of room temperature ferromagnetic Ge1-xMnx quantum dots on hydrogen passivated Si (100) surfaces

    Science.gov (United States)

    Gastaldo, Daniele; Conta, Gianluca; Coïsson, Marco; Amato, Giampiero; Tiberto, Paola; Allia, Paolo

    2018-05-01

    A method for the synthesis of room-temperature ferromagnetic dilute semiconductor Ge1-xMnx (5 % < x < 8 %) quantum dots by molecular beam epitaxy by selective growth on hydrogen terminated silicon (100) surface is presented. The functionalized substrates, as well as the nanostructures, were characterized in situ by reflection high-energy electron diffraction. The quantum dots density and equivalent radius were extracted from field emission scanning electron microscope pictures, obtained ex-situ. Magnetic characterizations were performed by superconducting quantum interference device vibrating sample magnetometry revealing that ferromagnetic order is maintained up to room temperature: two different ferromagnetic phases were identified by the analysis of the field cooled - zero field cooled measurements.

  12. Force-detected nanoscale absorption spectroscopy in water at room temperature using an optical trap

    Science.gov (United States)

    Parobek, Alexander; Black, Jacob W.; Kamenetska, Maria; Ganim, Ziad

    2018-04-01

    Measuring absorption spectra of single molecules presents a fundamental challenge for standard transmission-based instruments because of the inherently low signal relative to the large background of the excitation source. Here we demonstrate a new approach for performing absorption spectroscopy in solution using a force measurement to read out optical excitation at the nanoscale. The photoinduced force between model chromophores and an optically trapped gold nanoshell has been measured in water at room temperature. This photoinduced force is characterized as a function of wavelength to yield the force spectrum, which is shown to be correlated to the absorption spectrum for four model systems. The instrument constructed for these measurements combines an optical tweezer with frequency domain absorption spectroscopy over the 400-800 nm range. These measurements provide proof-of-principle experiments for force-detected nanoscale spectroscopies that operate under ambient chemical conditions.

  13. Control of room-temperature defect-mediated ferromagnetism in VO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tsung-Han, E-mail: tyang3@ncsu.edu [NSF Center for Advanced Materials and Smart Structures, Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907 (United States); Nori, Sudhakar; Mal, Siddhartha; Narayan, Jagdish [NSF Center for Advanced Materials and Smart Structures, Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907 (United States)

    2011-09-15

    We report interesting ferromagnetic properties and their control in a vanadium-based oxide system driven by stoichiometric defects. Vanadium oxide (VO{sub 2}) thin films were grown on c-plane sapphire substrates by a pulsed laser deposition technique under different ambient conditions. The ferromagnetism of the epitaxial VO{sub 2} films can be switched on and off by altering the cooling ambient parameters. In addition, the saturated magnetic moments and coercivity of the VO{sub 2} films were found to be a function of the oxygen partial pressure during the growth process. The room-temperature ferromagnetic properties of VO{sub 2} films were correlated with the nature of the microstructure and the growth parameters. The origin of the induced magnetic properties are qualitatively understood to stem from intrinsic structural and stoichiometric defects.

  14. Dual origin of room temperature sub-terahertz photoresponse in graphene field effect transistors

    Science.gov (United States)

    Bandurin, D. A.; Gayduchenko, I.; Cao, Y.; Moskotin, M.; Principi, A.; Grigorieva, I. V.; Goltsman, G.; Fedorov, G.; Svintsov, D.

    2018-04-01

    Graphene is considered as a promising platform for detectors of high-frequency radiation up to the terahertz (THz) range due to its superior electron mobility. Previously, it has been shown that graphene field effect transistors (FETs) exhibit room temperature broadband photoresponse to incoming THz radiation, thanks to the thermoelectric and/or plasma wave rectification. Both effects exhibit similar functional dependences on the gate voltage, and therefore, it was difficult to disentangle these contributions in previous studies. In this letter, we report on combined experimental and theoretical studies of sub-THz response in graphene field-effect transistors analyzed at different temperatures. This temperature-dependent study allowed us to reveal the role of the photo-thermoelectric effect, p-n junction rectification, and plasmonic rectification in the sub-THz photoresponse of graphene FETs.

  15. Three-dimensional scanning force/tunneling spectroscopy at room temperature

    International Nuclear Information System (INIS)

    Sugimoto, Yoshiaki; Ueda, Keiichi; Abe, Masayuki; Morita, Seizo

    2012-01-01

    We simultaneously measured the force and tunneling current in three-dimensional (3D) space on the Si(111)-(7 × 7) surface using scanning force/tunneling microscopy at room temperature. The observables, the frequency shift and the time-averaged tunneling current were converted to the physical quantities of interest, i.e. the interaction force and the instantaneous tunneling current. Using the same tip, the local density of states (LDOS) was mapped on the same surface area at constant height by measuring the time-averaged tunneling current as a function of the bias voltage at every lateral position. LDOS images at negative sample voltages indicate that the tip apex is covered with Si atoms, which is consistent with the Si-Si covalent bonding mechanism for AFM imaging. A measurement technique for 3D force/current mapping and LDOS imaging on the equivalent surface area using the same tip was thus demonstrated. (paper)

  16. Room-Temperature Single-photon level Memory for Polarization States

    Science.gov (United States)

    Kupchak, Connor; Mittiga, Thomas; Jordaan, Bertus; Namazi, Mehdi; Nölleke, Christian; Figueroa, Eden

    2015-01-01

    An optical quantum memory is a stationary device that is capable of storing and recreating photonic qubits with a higher fidelity than any classical device. Thus far, these two requirements have been fulfilled for polarization qubits in systems based on cold atoms and cryogenically cooled crystals. Here, we report a room-temperature memory capable of storing arbitrary polarization qubits with a signal-to-background ratio higher than 1 and an average fidelity surpassing the classical benchmark for weak laser pulses containing 1.6 photons on average, without taking into account non-unitary operation. Our results demonstrate that a common vapor cell can reach the low background noise levels necessary for polarization qubit storage using single-photon level light, and propels atomic-vapor systems towards a level of functionality akin to other quantum information processing architectures.

  17. Room temperature exchange bias in SmFeO_3 single crystal

    International Nuclear Information System (INIS)

    Wang, Xiaoxiong; Cheng, Xiangyi; Gao, Shang; Song, Junda; Ruan, Keqing; Li, Xiaoguang

    2016-01-01

    Exchange bias phenomenon is generally ascribed to the unidirectional magnetic shift along the field axes at interface of two magnetic materials. Room temperature exchange bias is found in SmFeO_3 single crystal. The behavior after different cooling procedure is regular, and the training behavior is attributed to the athermal training and its pinning origin is attributed to the antiferromagnetic clusters. Its being single phase and occurring at room temperature make it an appropriate candidate for application. - Graphical abstract: Room temperature exchange bias was found in oxide single crystal. Highlights: • Room temperature exchange bias has been discovered in single-crystalline SmFeO_3. • Its pinning origin is attributed to the antiferromagnetic clusters. • Its being single phase and occurring at room temperature make it an appropriate candidate for application.

  18. A facile route for irreversible bonding of plastic-PDMS hybrid microdevices at room temperature.

    Science.gov (United States)

    Tang, Linzhi; Lee, Nae Yoon

    2010-05-21

    Plastic materials do not generally form irreversible bonds with poly(dimethylsiloxane) (PDMS) regardless of oxygen plasma treatment and a subsequent thermal process. In this paper, we perform plastic-PDMS bonding at room temperature, mediated by the formation of a chemically robust amine-epoxy bond at the interfaces. Various plastic materials, such as poly(methylmethacrylate) (PMMA), polycarbonate (PC), polyimide (PI), and poly(ethylene terephthalate) (PET) were adopted as choices for plastic materials. Irrespective of the plastic materials used, the surfaces were successfully modified with amine and epoxy functionalities, confirmed by the surface characterizations such as water contact angle measurements and X-ray photoelectron spectroscopy (XPS), and chemically robust and irreversible bonding was successfully achieved within 1 h at room temperature. The bonding strengths of PDMS with PMMA and PC sheets were measured to be 180 and 178 kPa, respectively, and their assemblies containing microchannel structures endured up to 74 and 84 psi (510 and 579 kPa) of introduced compressed air, respectively, without destroying the microdevices, representing a robust and highly stable interfacial bonding. In addition to microchannel-molded PDMS bonded with flat plastic substrates, microchannel-embossed plastics were also bonded with a flat PDMS sheet, and both types of bonded assemblies displayed sufficiently robust bonding, tolerating an intense influx of liquid whose per-minute injection volume was nearly 1000 to 2000 times higher than the total internal volume of the microchannel used. In addition to observing the bonding performance, we also investigated the potential of surface amine and epoxy functionalities as durable chemical adhesives by observing their storage-time-dependent bonding performances.

  19. On an Iteration Leading to a q-Analogue of the Digamma Function

    DEFF Research Database (Denmark)

    Berg, Christian; Petersen, Helle Bjerg

    2013-01-01

    We show that the q-Digamma function ψq for 0 < q < 1 appears in an iteration studied by Berg and Durán. This is connected with the determination of the probability measure νq on the unit interval with moments 1/n+1 k=1(1 − q)/(1 − qk), which are q-analogues of the reciprocals of the harmonic numb...

  20. Sunlight Induced Rapid Oil Absorption and Passive Room-Temperature Release: An Effective Solution toward Heavy Oil Spill Cleanup

    KAUST Repository

    Wu, Mengchun

    2018-05-18

    Rapid cleanup and easy recovery of spilled heavy oils is always a great challenge due to their high viscosity (>103 mPa s). One of the efficient methods to absorb highly viscous oils is to reduce their viscosity by increasing their temperature. In this work, the authors integrate the sunlight‐induced light‐to‐heat conversion effect of polypyrrole (PPy) and thermoresponsive property of poly(N‐isopropylacrylamide) (PNIPAm) into the melamine sponge, which successfully delivers a fast heavy oil absorption under sunlight and passive oil release underwater at room temperature. Thanks to the rationally designed functionalities, the PNIPAm/PPy functionalized sponges possess oleophilicity and hydrophobicity under sunlight. Due to the photothermal effect of PPy, the sponges locally heat up contacting heavy oil under sunlight and reduce its viscosity to a point where the oil voluntarily flow into the pores of the sponge. The material in this work is able to rapidly absorb the heavy oil with room temperature viscosity as high as ≈1.60 × 105 mPa s. The absorbed oil can be passively forced out the sponge underwater at room temperature due to the hydrophilicity of PNIPAm. The sunlight responsive and multifunctional sponge represents a meaningful attempt in coming up with a sustainable solution toward heavy oil spill.

  1. Sunlight Induced Rapid Oil Absorption and Passive Room-Temperature Release: An Effective Solution toward Heavy Oil Spill Cleanup

    KAUST Repository

    Wu, Mengchun; Shi, Yusuf; Chang, Jian; Li, Renyuan; Ong, Chi Siang; Wang, Peng

    2018-01-01

    Rapid cleanup and easy recovery of spilled heavy oils is always a great challenge due to their high viscosity (>103 mPa s). One of the efficient methods to absorb highly viscous oils is to reduce their viscosity by increasing their temperature. In this work, the authors integrate the sunlight‐induced light‐to‐heat conversion effect of polypyrrole (PPy) and thermoresponsive property of poly(N‐isopropylacrylamide) (PNIPAm) into the melamine sponge, which successfully delivers a fast heavy oil absorption under sunlight and passive oil release underwater at room temperature. Thanks to the rationally designed functionalities, the PNIPAm/PPy functionalized sponges possess oleophilicity and hydrophobicity under sunlight. Due to the photothermal effect of PPy, the sponges locally heat up contacting heavy oil under sunlight and reduce its viscosity to a point where the oil voluntarily flow into the pores of the sponge. The material in this work is able to rapidly absorb the heavy oil with room temperature viscosity as high as ≈1.60 × 105 mPa s. The absorbed oil can be passively forced out the sponge underwater at room temperature due to the hydrophilicity of PNIPAm. The sunlight responsive and multifunctional sponge represents a meaningful attempt in coming up with a sustainable solution toward heavy oil spill.

  2. Amorphous indium tin oxide films deposited on flexible substrates by facing target sputtering at room temperature

    International Nuclear Information System (INIS)

    Xiao, Yu; Gao, Fangyuan; Dong, Guobo; Guo, Tingting; Liu, Qirong; Ye, Di; Diao, Xungang

    2014-01-01

    Indium tin oxide (ITO) thin films were deposited on polyethylene terephthalate substrates using a DC facing target sputtering (DC-FTS) system at room temperature. The sputtering conditions including oxygen partial pressure and discharge current were varied from 0% to 4% and 0.5 A to 1.3 A, respectively. X-ray diffraction and scanning electron microscopy were used to study the structure and surface morphology of as-prepared films. All the films exhibited amorphous structures and smooth surfaces. The dependence of electrical and optical properties on various deposition parameters was investigated by a linear array four-point probe, Hall-effect measurements, and ultraviolet/visible spectrophotometry. A lowest sheet resistance of 17.4 Ω/square, a lowest resistivity of 3.61 × 10 −4 Ω cm, and an average relative transmittance over 88% in the visible range were obtained under the optimal deposition conditions. The relationship between the Hall mobility (μ) and carrier concentration (n) was interpreted by a functional relation of μ ∼ n −0.127 , which indicated that ionized donor scattering was the dominant electron scattering mechanism. It is also confirmed that the carrier concentration in ITO films prepared by the DC-FTS system is mainly controlled by the number of activated Sn donors rather than oxygen vacancies. - Highlights: • ITO thin films were grown on PET substrates by DC facing target sputtering system. • All the films were prepared at room temperature and exhibited amorphous structure. • Highly conductive and transparent ITO thin films were obtained. • The dominant ionized donor scattering mechanism was suggested

  3. Amorphous indium tin oxide films deposited on flexible substrates by facing target sputtering at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Yu [Solar Film Laboratory, School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Gao, Fangyuan, E-mail: gaofangyuan@buaa.edu.cn [Solar Film Laboratory, School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Dong, Guobo; Guo, Tingting; Liu, Qirong [Solar Film Laboratory, School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Ye, Di [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100191 (China); Diao, Xungang [Solar Film Laboratory, School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China)

    2014-04-01

    Indium tin oxide (ITO) thin films were deposited on polyethylene terephthalate substrates using a DC facing target sputtering (DC-FTS) system at room temperature. The sputtering conditions including oxygen partial pressure and discharge current were varied from 0% to 4% and 0.5 A to 1.3 A, respectively. X-ray diffraction and scanning electron microscopy were used to study the structure and surface morphology of as-prepared films. All the films exhibited amorphous structures and smooth surfaces. The dependence of electrical and optical properties on various deposition parameters was investigated by a linear array four-point probe, Hall-effect measurements, and ultraviolet/visible spectrophotometry. A lowest sheet resistance of 17.4 Ω/square, a lowest resistivity of 3.61 × 10{sup −4} Ω cm, and an average relative transmittance over 88% in the visible range were obtained under the optimal deposition conditions. The relationship between the Hall mobility (μ) and carrier concentration (n) was interpreted by a functional relation of μ ∼ n{sup −0.127}, which indicated that ionized donor scattering was the dominant electron scattering mechanism. It is also confirmed that the carrier concentration in ITO films prepared by the DC-FTS system is mainly controlled by the number of activated Sn donors rather than oxygen vacancies. - Highlights: • ITO thin films were grown on PET substrates by DC facing target sputtering system. • All the films were prepared at room temperature and exhibited amorphous structure. • Highly conductive and transparent ITO thin films were obtained. • The dominant ionized donor scattering mechanism was suggested.

  4. Bisphenol A is released from used polycarbonate animal cages into water at room temperature

    Science.gov (United States)

    Howdeshell, Kembra L.; Peterman, Paul H.; Judy, Barbara M.; Taylor, Julia A.; Orazio, Carl E.; Ruhlen, Rachel L.; vom Saal, Frederick S.; Welshons, Wade V.

    2003-01-01

    Bisphenol A (BPA) is a monomer with estrogenic activity that is used in the production of food packaging, dental sealants, polycarbonate plastic, and many other products. The monomer has previously been reported to hydrolyze and leach from these products under high heat and alkaline conditions, and the amount of leaching increases as a function of use. We examined whether new and used polycarbonate animal cages passively release bioactive levels of BPA into water at room temperature and neutral pH. Purified water was incubated at room temperature in new polycarbonate and polysulfone cages and used (discolored) polycarbonate cages, as well as control (glass and used polypropylene) containers. The resulting water samples were characterized with gas chromatography/mass spectrometry (GC/MS) and tested for estrogenic activity using an MCF-7 human breast cancer cell proliferation assay. Significant estrogenic activity, identifiable as BPA by GC/MS (up to 310 micro g/L), was released from used polycarbonate animal cages. Detectable levels of BPA were released from new polycarbonate cages (up to 0.3 micro g/L) as well as new polysulfone cages (1.5 micro g/L), whereas no BPA was detected in water incubated in glass and used polypropylene cages. Finally, BPA exposure as a result of being housed in used polycarbonate cages produced a 16% increase in uterine weight in prepubertal female mice relative to females housed in used polypropylene cages, although the difference was not statistically significant. Our findings suggest that laboratory animals maintained in polycarbonate and polysulfone cages are exposed to BPA via leaching, with exposure reaching the highest levels in old cages.

  5. Photophysics of α-furil at room temperature and 77 K: Spectroscopic and quantum chemical studies

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Pronab; Chattopadhyay, Nitin, E-mail: nitin.chattopadhyay@yahoo.com [Department of Chemistry, Jadavpur University, Kolkata 700 032 (India)

    2016-06-21

    Steady state and time resolved spectroscopic measurements have been exploited to assign the emissions from different conformations of α-furil (2, 2′-furil) in solution phase at room temperature as well as cryogen (liquid nitrogen, LN{sub 2}) frozen matrices of ethanol and methylcyclohexane. Room temperature studies reveal a single fluorescence from the trans-planar conformer of the fluorophore or two fluorescence bands coming from the trans-planar and the relaxed skew forms depending on excitation at the nπ{sup ∗} or the ππ{sup ∗} absorption band, respectively. Together with the fluorescence bands, the LN{sub 2} studies in both the solvents unambiguously ascertain two phosphorescence emissions with lifetimes 5 ± 0.3 ms (trans-planar triplet) and 81 ± 3 ms (relaxed skew triplet). Quantum chemical calculations have been performed using density functional theory at CAM-B3LYP/6-311++G{sup ∗∗} level to prop up the spectroscopic surveillance. The simulated potential energy curves (PECs) illustrate that α-furil is capable of giving two emissions from each of the S{sub 1} and the T{sub 1} states—one corresponding to the trans-planar and the other to the relaxed skew conformation. Contrary to the other 1,2-dicarbonyl molecular systems like benzil and α-naphthil, α-furil does not exhibit any fluorescence from its second excited singlet (S{sub 2}) state. This is ascribed to the proximity of the minimum of the PEC of the S{sub 2} state and the hill-top of the PEC of the S{sub 1} state.

  6. Proton conducting hydrocarbon membranes: Performance evaluation for room temperature direct methanol fuel cells

    International Nuclear Information System (INIS)

    Krivobokov, Ivan M.; Gribov, Evgeniy N.; Okunev, Alexey G.

    2011-01-01

    The methanol permeability, proton conductivity, water uptake and power densities of direct methanol fuel cells (DMFCs) at room temperature are reported for sulfonated hydrocarbon (sHC) and perfluorinated (PFSA) membranes from Fumatech, and compared to Nafion membranes. The sHC membranes exhibit lower proton conductivity (25-40 mS cm -1 vs. ∼95-40 mS cm -1 for Nafion) as well as lower methanol permeability (1.8-3.9 x 10 -7 cm 2 s -1 vs. 2.4-3.4 x 10 -6 cm 2 s -1 for Nafion). Water uptake was similar for all membranes (18-25 wt%), except for the PFSA membrane (14 wt%). Methanol uptake varied from 67 wt% for Nafion to 17 wt% for PFSA. The power density of Nafion in DMFCs at room temperature decreases with membrane thickness from 26 mW cm -2 for Nafion 117 to 12.5 mW cm -2 for Nafion 112. The maximum power density of the Fumatech membranes ranges from 4 to 13 mW cm -1 . Conventional transport parameters such as membrane selectivity fail to predict membrane performance in DMFCs. Reliable and easily interpretable results are obtained when the power density is plotted as a function of the transport factor (TF), which is the product of proton concentration in the swollen membrane and the methanol flux. At low TF values, cell performance is limited by low proton conductivity, whereas at high TF values it decreases due to methanol crossover. The highest maximum power density corresponds to intermediate values of TF.

  7. Optical detection of symmetric and antisymmetric states in double quantum wells at room temperature

    Science.gov (United States)

    Marchewka, M.; Sheregii, E. M.; Tralle, I.; Marcelli, A.; Piccinini, M.; Cebulski, J.

    2009-09-01

    We studied the optical reflectivity of a specially grown double quantum well (DQW) structure characterized by a rectangular shape and a high electron density at room temperature. Assuming that the QWs depth is known, reflectivity spectra in the mid-IR range allow to carry out the precise measurements of the SAS-gap values (the energy gap between the symmetric and anti-symmetric states) and the absolute energies of both symmetric and antisymmetric electron states. The results of our experiments are in favor of the existence of the SAS splitting in the DQWs at room temperature. Here we have shown that the SAS gap increases proportionally to the subband quantum number and the optical electron transitions between symmetric and antisymmetric states belonging to different subbands are allowed. These results were used for interpretation of the beating effect in the Shubnikov-de Haas (SdH) oscillations at low temperatures (0.6 and 4.2 K). The approach to the calculation of the Landau-levels energies for DQW structures developed earlier [D. Ploch , Phys. Rev. B 79, 195434 (2009)] is used for the analysis and interpretation of the experimental data related to the beating effect. We also argue that in order to explain the beating effect in the SdH oscillations, one should introduce two different quasi-Fermi levels characterizing the two electron subsystems regarding symmetry properties of their wave functions, symmetric and antisymmetric ones. These states are not mixed neither by electron-electron interaction nor probably by electron-phonon interaction.

  8. Room temperature lasing unraveled by a strong resonance between gain and parasitic absorption in uniaxially strained germanium

    Science.gov (United States)

    Gupta, Shashank; Nam, Donguk; Vuckovic, Jelena; Saraswat, Krishna

    2018-04-01

    A complementary metal-oxide semiconductor compatible on-chip light source is the holy grail of silicon photonics and has the potential to alleviate the key scaling issues arising due to electrical interconnects. Despite several theoretical predictions, a sustainable, room temperature laser from a group-IV material is yet to be demonstrated. In this work, we show that a particular loss mechanism, inter-valence-band absorption (IVBA), has been inadequately modeled until now and capturing its effect accurately as a function of strain is crucial to understanding light emission processes from uniaxially strained germanium (Ge). We present a detailed model of light emission in Ge that accurately models IVBA in the presence of strain and other factors such as polarization, doping, and carrier injection, thereby revising the road map toward a room temperature Ge laser. Strikingly, a special resonance between gain and loss mechanisms at 4%-5% 〈100 〉 uniaxial strain is found resulting in a high net gain of more than 400 cm-1 at room temperature. It is shown that achieving this resonance should be the goal of experimental work rather than pursuing a direct band gap Ge.

  9. Prussian Blue Analogues of Reduced Dimensionality

    NARCIS (Netherlands)

    Gengler, Regis Y. N.; Toma, Luminita M.; Pardo, Emilio; Lloret, Francesc; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Gournis, Dimitrios; Rudolf, Petra

    2012-01-01

    Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While

  10. Biomimetic and Aggregation-Driven Crystallization Route for Room-Temperature Material Synthesis: Growth of β-Ga2O3 Nanoparticles Using Peptide Assemblies as Nanoreactors

    Science.gov (United States)

    Lee, Sang-Yup; Gao, Xueyun; Matsui, Hiroshi

    2008-01-01

    The room temperature synthesis of β-Ga2O3 nanocrystal was examined by coupling two biomimetic crystallization techniques, the enzymatic peptide nano-assembly templating and the aggregation-driven crystallization. The catalytic template of peptide assembly nucleated and mineralized primary β-Ga2O3 crystals, and then fused them to grow single-crystalline and monodisperse nanoparticles in the cavity of the peptide assembly at room temperature. In this work, the peptide assembly was exploited as a nano-reactor with an enzymatic functionality catalyzing the hydrolysis of gallium precursors. In addition, the characteristic ring-structure of peptide assembly is expected to provide an efficient dehydration pathway and the crystallization control over the surface tension, which are advantageous for the β-Ga2O3 crystal growth. This multifunctional peptide assembly could be applied for syntheses of a variety of nanomaterials that are kinetically difficult to grow at room temperature. PMID:17302413

  11. Structural and electrical properties of room temperature pulsed laser deposited and post-annealed thin SrRuO3 films

    International Nuclear Information System (INIS)

    Gautreau, O.; Harnagea, C.; Normandin, F.; Veres, T.; Pignolet, A.

    2007-01-01

    Good quality strontium ruthenate (SrRuO 3 ) thin continuous films (15 to 125 nm thick) have been synthesized on silicon (100) substrates by room temperature pulsed laser deposition under vacuum followed by a post-deposition annealing, a route unexplored and yet not reported for SrRuO 3 film growth. The presence of an interfacial Sr 2 SiO 4 layer has been identified for films annealed at high temperature, and the properties of this interface layer as well as the properties of the SrRuO 3 film have been analyzed and characterized as a function of the annealing temperature. The room temperature resistivity of the SrRuO 3 films deposited by laser ablation at room temperature and post-annealed is 2000 μΩ.cm. A critical thickness of 120 nm has been determined above which the influence of the interface layer on the resistivity becomes negligible

  12. Red photoluminescence of living systems at the room temperature: measurements and results

    International Nuclear Information System (INIS)

    Kudryashova, I S; Rud, V Yu; Shpunt, V Ch; Rud, Yu V; Glinushkin, A P

    2016-01-01

    Presents results of a study of the red luminescence of living plants at room temperature. The analysis of obtained results allows to conclude that the photoluminescence spectra for green leaves in all cases represent the two closely spaced bands. (paper)

  13. Stability of 2-Alkylcyclobutanones in irradiated retort pouch Gyudon topping during room temperature storage

    International Nuclear Information System (INIS)

    Kitagawa, Yoko; Okihashi, Masahiro; Takatori, Satoshi; Fukui, Naoki; Kajimura, Keiji; Obana, Hirotaka; Furuta, Masakazu

    2016-01-01

    2-Alkylcyclobutanones (ACBs), such as 2-dodecylcyclobutanone (DCB) and 2-tetradecylcylobutanone (TCB) are specific products in the irradiated liquid. Thus, DCB and TCB are suitable for indicators of the irradiation history of food. We previously reported DCB and TCB concentrations in irradiated retort pouch Gyudon topping (instant Gyudon mixes which were made from a beef, onion and soy sauce and could be preserved for a long term at room temperature) after storage for one year. Here, we have evaluated the stability of ACBs preserved in irradiated retort pouch Gyudon topping at room temperature for three years. Although interfering peaks were detected frequently after the storage at room temperature, it was possible for the detection of the irradiation history and there was no apparent decrease of ACBs concentrations in comparison with the one year storage after irradiation. These results concluded that DCB and TCB formed in retort pouch would be stable at room temperature for three years. (author)

  14. Hydrogen-induced room-temperature plasticity in TC4 and TC21 alloys

    DEFF Research Database (Denmark)

    Yuan, Baoguo; Jin, Yongyue; Hong, Chuanshi

    2017-01-01

    In order to reveal the effect of hydrogen on the room-temperature plasticity of the titanium alloys TC4 and TC21, compression tests have been carried out at room temperature. Results show that an appropriate amount of hydrogen can improve the room-temperature plasticity of both the TC4 and TC21...... alloys. The ultimate compression strain of the TC4 alloy containing a hydrogen concentration of 0.5 wt.% increases by 39% compared to the untreated material. For the TC21 alloy the ultimate compression strain is increased by 33% at a hydrogen concentration of 0.6 wt.%. The main reason for the improvement...... of hydrogen-induced room-temperature plasticity of the TC4 and TC21 alloys is discussed....

  15. Controlled laser biochemistry in room-temperature polar liquids by ultrashort laser pulses

    DEFF Research Database (Denmark)

    Gruzdev, Vitaly; Korkin, Dmitry; Mooney, Brian P.

    2018-01-01

    Traditional laser methods to control chemical modifications of biomolecules are not applicable under biologically relevant conditions. We report controlled modifications of peptides and insulin by femtosecond laser in water, methanol, and acetonitrile at room temperature...

  16. Branched carbon nanofiber network synthesis at room temperature using radio frequency supported microwave plasmas

    International Nuclear Information System (INIS)

    Boskovic, Bojan O.; Stolojan, Vlad; Zeze, Dagou A.; Forrest, Roy D.; Silva, S. Ravi P.; Haq, Sajad

    2004-01-01

    Carbon nanofibers have been grown at room temperature using a combination of radio frequency and microwave assisted plasma-enhanced chemical vapor deposition. The nanofibers were grown, using Ni powder catalyst, onto substrates kept at room temperature by using a purposely designed water-cooled sample holder. Branched carbon nanofiber growth was obtained without using a template resulting in interconnected carbon nanofiber network formation on substrates held at room temperature. This method would allow room-temperature direct synthesized nanofiber networks over relatively large areas, for a range of temperature sensitive substrates, such as organic materials, plastics, and other polymers of interest for nanoelectronic two-dimensional networks, nanoelectromechanical devices, nanoactuators, and composite materials

  17. Nickel-catalyzed synthesis of aryl trifluoromethyl sulfides at room temperature.

    Science.gov (United States)

    Zhang, Cheng-Pan; Vicic, David A

    2012-01-11

    Inexpensive nickel-bipyridine complexes were found to be active for the trifluoromethylthiolation of aryl iodides and aryl bromides at room temperature using the convenient [NMe(4)][SCF(3)] reagent. © 2011 American Chemical Society

  18. Room-Temperature Single-Photon Source for Secure Quantum Communication

    Data.gov (United States)

    National Aeronautics and Space Administration — We are asking for four years of support for PhD student Justin Winkler's work on a research project entitled "Room temperature single photon source for secure...

  19. Influence of sequential room-temperature compressive creep on flow stress of TA2

    Science.gov (United States)

    Mengyuan, Zhang; Boqin, Gu; Jiahui, Tao

    2018-03-01

    This paper studied the sequential room temperature compressive creep and its effects on compressive properties of TA2 with stress-control loading pattern by using cylindrical compressive test specimen. The significant time-dependent deformation under constant load was observed in the TA2 at room temperature, and the deformation was dependent on the loading process under the same loading stress rate. It was also found that the occurrence of room temperature compressive creep obviously enhanced the subsequent yielding strength and flow stress of TA2 due to the increase of network dislocation density. And the effects of room temperature creep on the strain rate-stress behavior could be explained by the local mobile dislocation density model.

  20. Dispersion and Solvation Effects on the Structure and Dynamics of N719 Adsorbed to Anatase Titania (101) Surfaces in Room-Temperature Ionic Liquids: An ab Initio Molecular Simulation Study

    KAUST Repository

    Byrne, Aaron; English, Niall J.; Schwingenschlö gl, Udo; Coker, David F.

    2015-01-01

    Ab initio, density functional theory (DFT)-based molecular dynamics (MD) has been carried out to investigate the effect of explicit solvation on the dynamical and structural properties of a [bmim][NTf2] room-temperature ionic liquid (RTIL

  1. Room-temperature Pd-catalyzed C-H chlorination by weak coordination: one-pot synthesis of 2-chlorophenols with excellent regioselectivity.

    Science.gov (United States)

    Sun, Xiuyun; Sun, Yonghui; Zhang, Chao; Rao, Yu

    2014-02-07

    A room-temperature Pd(II)-catalyzed regioselective chlorination reaction has been developed for a facile one-pot synthesis of a broad range of 2-chlorophenols. The reaction demonstrates an excellent regioselectivity and reactivity for C-H chlorination. This reaction represents one of the rare examples of mild C-H functionalization at ambient temperature.

  2. On q-analogues of the Mangontarum transform for certain q-Bessel functions and some application

    Directory of Open Access Journals (Sweden)

    S.K.Q. Al-Omari

    2016-10-01

    Full Text Available Several q-analogues of certain integral transforms have been recently investigated by many authors in the recent past. In this paper, we introduce certain analogues of the so-called q-Mangontarum transform and implement the proposed variants to given classes of q-Bessel functions. The results of this paper are new and complement the previously known results of Mangontarum (2014. Some results related to q-Laplace transforms are also obtained.

  3. Gene analogue finder: a GRID solution for finding functionally analogous gene products

    Directory of Open Access Journals (Sweden)

    Licciulli Flavio

    2007-09-01

    Full Text Available Abstract Background To date more than 2,1 million gene products from more than 100000 different species have been described specifying their function, the processes they are involved in and their cellular localization using a very well defined and structured vocabulary, the gene ontology (GO. Such vast, well defined knowledge opens the possibility of compare gene products at the level of functionality, finding gene products which have a similar function or are involved in similar biological processes without relying on the conventional sequence similarity approach. Comparisons within such a large space of knowledge are highly data and computing intensive. For this reason this project was based upon the use of the computational GRID, a technology offering large computing and storage resources. Results We have developed a tool, GENe AnaloGue FINdEr (ENGINE that parallelizes the search process and distributes the calculation and data over the computational GRID, splitting the process into many sub-processes and joining the calculation and the data on the same machine and therefore completing the whole search in about 3 days instead of occupying one single machine for more than 5 CPU years. The results of the functional comparison contain potential functional analogues for more than 79000 gene products from the most important species. 46% of the analyzed gene products are well enough described for such an analysis to individuate functional analogues, such as well-known members of the same gene family, or gene products with similar functions which would never have been associated by standard methods. Conclusion ENGINE has produced a list of potential functionally analogous relations between gene products within and between species using, in place of the sequence, the gene description of the GO, thus demonstrating the potential of the GO. However, the current limiting factor is the quality of the associations of many gene products from non

  4. Room temperature ductility of NiAl-strengthened ferritic steels: Effects of precipitate microstructure

    International Nuclear Information System (INIS)

    Teng, Z.K.; Liu, C.T.; Miller, M.K.; Ghosh, G.; Kenik, E.A.; Huang, S.; Liaw, P.K.

    2012-01-01

    Highlights: ► Effects of precipitate microstructure on the ductility were investigated. ► The NiAl precipitates can be systematically characterized by TEM, APT, and USAXS. ► Ductility is a function of the precipitate volume fraction. ► Ductility is closely related to the Al and Ni solubilities in the Fe matrix. ► Ductility is independent of precipitate size and inter-particle spacing. - Abstract: The effects of precipitate microstructure on the room temperature ductility of a series of carefully designed Fe–Al–Ni–Cr–Mo steels were investigated. Transmission electron microscopy (TEM), ultra small angle X-ray scattering (USAXS), and atom probe tomography (APT) were conducted to quantify the nano-scaled precipitates. The accuracy of the characterization results was verified by a numerical analysis. Three point bending tests results demonstrated that ductility was a function of the precipitate volume fraction and the Al and Ni concentrations in the Fe matrix, these relationships were discussed in terms of possible mechanisms. The ductility was also found to be independent of the precipitate size and inter-particle spacing in the studied range, which was validated by a theoretical model.

  5. Room-temperature current blockade in atomically defined single-cluster junctions

    Science.gov (United States)

    Lovat, Giacomo; Choi, Bonnie; Paley, Daniel W.; Steigerwald, Michael L.; Venkataraman, Latha; Roy, Xavier

    2017-11-01

    Fabricating nanoscopic devices capable of manipulating and processing single units of charge is an essential step towards creating functional devices where quantum effects dominate transport characteristics. The archetypal single-electron transistor comprises a small conducting or semiconducting island separated from two metallic reservoirs by insulating barriers. By enabling the transfer of a well-defined number of charge carriers between the island and the reservoirs, such a device may enable discrete single-electron operations. Here, we describe a single-molecule junction comprising a redox-active, atomically precise cobalt chalcogenide cluster wired between two nanoscopic electrodes. We observe current blockade at room temperature in thousands of single-cluster junctions. Below a threshold voltage, charge transfer across the junction is suppressed. The device is turned on when the temporary occupation of the core states by a transiting carrier is energetically enabled, resulting in a sequential tunnelling process and an increase in current by a factor of ∼600. We perform in situ and ex situ cyclic voltammetry as well as density functional theory calculations to unveil a two-step process mediated by an orbital localized on the core of the cluster in which charge carriers reside before tunnelling to the collector reservoir. As the bias window of the junction is opened wide enough to include one of the cluster frontier orbitals, the current blockade is lifted and charge carriers can tunnel sequentially across the junction.

  6. Enhancement of NH3 gas sensitivity at room temperature by carbon nanotube-based sensor coated with Co nanoparticles.

    Science.gov (United States)

    Nguyen, Lich Quang; Phan, Pho Quoc; Duong, Huyen Ngoc; Nguyen, Chien Duc; Nguyen, Lam Huu

    2013-01-30

    Multi-walled carbon nanotube (MWCNT) film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH(3) gas sensing applications. The MWCNT-based sensor is sensitive to NH(3) gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT films. The gas sensitivity of Co-functionalized MWCNT-based gas sensors is thus significantly improved. The sensor exhibits good repeatability and high selectivity towards NH(3), compared with alcohol and LPG.

  7. Room temperature adsorption of NH3 on Zn-terminated ZnO(0 0 0 1)

    International Nuclear Information System (INIS)

    Hasegawa, T.; Shirotori, Y.; Ozawa, K.; Edamoto, K.; Takahashi, K.

    2004-01-01

    Adsorption process of ammonia on the Zn-terminated ZnO(0 0 0 1) surface at room temperature has been studied by photoelectron spectroscopy utilizing synchrotron radiation. Coverage-dependent measurements of the N 1s core-level peak and the work function change have been carried out. It is revealed that ammonia adsorbs molecularly in the initial stages of adsorption, whereas deprotonated species are formed after some amount of molecular ammonia is accumulated on the surface. The reactivity of the K-modified ZnO(0 0 0 1) surface towards ammonia adsorption has also been investigated and found to be significantly lowered by predeposited K

  8. Numerical simulation of a quantum controlled-not gate implemented on four-spin molecules at room temperature

    CERN Document Server

    López, G V; Berman, G P; Doolen, G D; Tsifrinovich, V I

    2003-01-01

    We study numerically the non-resonant effects on four-spin molecules at room temperature with the implemented quantum controlled-not gate and using the 2 pi k method. The four nuclear spins in each molecule represent a four-qubit register. The qubits interact with each other through Ising-type interaction which is characterized by the coupling constant J sub a sub , sub b. We study the errors on the reduced density matrix as a function of the Rabi frequency, OMEGA, using the 2 pi k method and when all the coupling constants are equal or when one of them is different from the others.

  9. Enhancement of NH3 Gas Sensitivity at Room Temperature by Carbon Nanotube-Based Sensor Coated with Co Nanoparticles

    Directory of Open Access Journals (Sweden)

    Lich Quang Nguyen

    2013-01-01

    Full Text Available Multi-walled carbon nanotube (MWCNT film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH3 gas sensing applications. The MWCNT-based sensor is sensitive to NH3 gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT films. The gas sensitivity of Co-functionalized MWCNT-based gas sensors is thus significantly improved. The sensor exhibits good repeatability and high selectivity towards NH3, compared with alcohol and LPG.

  10. Room temperature synthesis of Ni-based alloy nanoparticles by radiolysis.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria; Berry, Donald T.; Lu, Ping; Leung, Kevin; Provencio, Paula Polyak; Stumpf, Roland Rudolph; Huang, Jian Yu; Zhang, Zhenyuan

    2009-09-01

    Room temperature radiolysis, density functional theory, and various nanoscale characterization methods were used to synthesize and fully describe Ni-based alloy nanoparticles (NPs) that were synthesized at room temperature. These complementary methods provide a strong basis in understanding and describing metastable phase regimes of alloy NPs whose reaction formation is determined by kinetic rather than thermodynamic reaction processes. Four series of NPs, (Ag-Ni, Pd-Ni, Co-Ni, and W-Ni) were analyzed and characterized by a variety of methods, including UV-vis, TEM/HRTEM, HAADF-STEM and EFTEM mapping. In the first focus of research, AgNi and PdNi were studied. Different ratios of Ag{sub x}- Ni{sub 1-x} alloy NPs and Pd{sub 0.5}- Ni{sub 0.5} alloy NP were prepared using a high dose rate from gamma irradiation. Images from high-angle annular dark-field (HAADF) show that the Ag-Ni NPs are not core-shell structure but are homogeneous alloys in composition. Energy filtered transmission electron microscopy (EFTEM) maps show the homogeneity of the metals in each alloy NP. Of particular interest are the normally immiscible Ag-Ni NPs. All evidence confirmed that homogeneous Ag-Ni and Pd-Ni alloy NPs presented here were successfully synthesized by high dose rate radiolytic methodology. A mechanism is provided to explain the homogeneous formation of the alloy NPs. Furthermore, studies of Pd-Ni NPs by in situ TEM (with heated stage) shows the ability to sinter these NPs at temperatures below 800 C. In the second set of work, CoNi and WNi superalloy NPs were attempted at 50/50 concentration ratios using high dose rates from gamma irradiation. Preliminary results on synthesis and characterization have been completed and are presented. As with the earlier alloy NPs, no evidence of core-shell NP formation occurs. Microscopy results seem to indicate alloying occurred with the CoNi alloys. However, there appears to be incomplete reduction of the Na{sub 2}WO{sub 4} to form the W

  11. Fast radioiodination of rose bengal at room temperature

    International Nuclear Information System (INIS)

    Verbruggen, R.F.

    1987-01-01

    Polyhalogenated dyes based on aromatic ring systems such as fluorosceins have been used for the evaluation of hepatobiliary function since 1909. In 1955 rose bengal was radioiodinated and a radiocontrastdye become a radiopharmaceutical. In the present study an improved method, based on the chloramine-T method, has been developed for labelling rose bengal. This method was chosen for its short reaction time, its mild conditions and its high yield. The optimum values of the reaction parameters have been determined, and resulted in a slightly higher yield, within a shorter time and without breakdown products being present

  12. Room temperature deposition of crystalline indium tin oxide films by cesium-assisted magnetron sputtering

    International Nuclear Information System (INIS)

    Lee, Deuk Yeon; Baik, Hong-Koo

    2008-01-01

    Indium tin oxide (ITO) films were deposited on a Si (1 0 0) substrate at room temperature by cesium-assisted magnetron sputtering. Including plasma characteristics, the structural, electrical, and optical properties of deposited films were investigated as a function of cesium partial vapor pressure controlled by cesium reservoir temperature. We calculated the cesium coverage on the target surface showing maximum formation efficiency of negative ions by means of the theoretical model. Cesium addition promotes the formation efficiency of negative ions, which plays important role in enhancing the crystallinity of ITO films. In particular, the plasma density was linearly increased with cesium concentrations. The resultant decrease in specific resistivity and increase in transmittance (82% in the visible region) at optimum cesium concentration (4.24 x 10 -4 Ω cm at 80 deg. C of reservoir temperature) may be due to enhanced crystallinity of ITO films. Excess cesium incorporation into ITO films resulted in amorphization of its microstructure leading to degradation of ITO crystallinity. We discuss the cesium effects based on the growth mechanism of ITO films and the plasma density

  13. Spin Transport in Nondegenerate Si with a Spin MOSFET Structure at Room Temperature

    Science.gov (United States)

    Sasaki, Tomoyuki; Ando, Yuichiro; Kameno, Makoto; Tahara, Takayuki; Koike, Hayato; Oikawa, Tohru; Suzuki, Toshio; Shiraishi, Masashi

    2014-09-01

    Spin transport in nondegenerate semiconductors is expected to pave the way to the creation of spin transistors, spin logic devices, and reconfigurable logic circuits, because room-temperature (RT) spin transport in Si has already been achieved. However, RT spin transport has been limited to degenerate Si, which makes it difficult to produce spin-based signals because a gate electric field cannot be used to manipulate such signals. Here, we report the experimental demonstration of spin transport in nondegenerate Si with a spin metal-oxide-semiconductor field-effect transistor (MOSFET) structure. We successfully observe the modulation of the Hanle-type spin-precession signals, which is a characteristic spin dynamics in nondegenerate semiconductors. We obtain long spin transport of more than 20 μm and spin rotation greater than 4π at RT. We also observe gate-induced modulation of spin-transport signals at RT. The modulation of the spin diffusion length as a function of a gate voltage is successfully observed, which we attribute to the Elliott-Yafet spin relaxation mechanism. These achievements are expected to lead to the creation of practical Si-based spin MOSFETs.

  14. Room temperature phosphorescence study on the structural flexibility of single tryptophan containing proteins

    Science.gov (United States)

    Kowalska-Baron, Agnieszka; Gałęcki, Krystian; Wysocki, Stanisław

    2015-01-01

    In this study, we have undertaken efforts to find correlation between phosphorescence lifetimes of single tryptophan containing proteins and some structural indicators of protein flexibility/rigidity, such as the degree of tryptophan burial or its exposure to solvent, protein secondary and tertiary structure of the region of localization of tryptophan as well as B factors for tryptophan residue and its immediate surroundings. Bearing in mind that, apart from effective local viscosity of the protein/solvent matrix, the other factor that concur in determining room temperature tryptophan phosphorescence (RTTP) lifetime in proteins is the extent of intramolecular quenching by His, Cys, Tyr and Trp side chains, the crystallographic structures derived from the Brookhaven Protein Data Bank were also analyzed concentrating on the presence of potentially quenching amino acid side chains in the close proximity of the indole chromophore. The obtained results indicated that, in most cases, the phosphorescence lifetimes of tryptophan containing proteins studied tend to correlate with the above mentioned structural indicators of protein rigidity/flexibility. This correlation is expected to provide guidelines for the future development of phosphorescence lifetime-based method for the prediction of structural flexibility of proteins, which is directly linked to their biological function.

  15. Stress relaxation in 'aged high-purity aluminium at room temperature

    International Nuclear Information System (INIS)

    Butt, M.Z.; Haq, I.U.

    1993-01-01

    Stress relaxation in 99.996% Al polycrystals of average grain diameter 0.30, 0.42 and 0.51 mm, annealed at 500 deg. C and 'aged' for six months at room temperature, have been studied as a function of initial stress level from which relaxation at constant strain was allowed to start. The results obtained were compared with those for 'un-aged' Al specimens of the same purity and grain size. The intrinsic height of the thermally activable energy barrier (1.6 eV) evaluated for 'aged' Al is comparable with that (1.9 eV) for 'un-aged' Al, and is of the order of magnitude for recovery processes. In 'aged' specimens, the relaxation rate at a given stress level is larger and associated activation volume is smaller than that in 'un-aged' specimens. This is probably due to the diffusion of vacancies and/or residual impurity atoms to the cores to edge dislocations in 'aged' specimens; the length of dislocation segment involved in unit activation process therefore gets shortened compared with that in 'un-aged' specimens. (author)

  16. Room-temperature Electrochemical Synthesis of Carbide-derived Carbons and Related Materials

    Energy Technology Data Exchange (ETDEWEB)

    Gogotsi, Yury [Drexel Univ., Philadelphia, PA (United States). Nanomaterials Group. Materials Science and Engineering Dept.

    2015-02-28

    This project addresses room-temperature electrochemical etching as an energy-efficient route to synthesis of 3D nanoporous carbon networks and layered 2D carbons and related structures, as well as provides fundamental understanding of structure and properties of materials produced by this method. Carbide-derived-carbons (CDCs) are a growing class of nanostructured carbon materials with properties that are desirable for many applications, such as electrical energy and gas storage. The structure of these functional materials is tunable by the choice of the starting carbide precursor, synthesis method, and process parameters. Moving from high-temperature synthesis of CDCs through vacuum decomposition above 1400°C and chlorination above 400°C, our studies under the previous DOE BES support led to identification of precursor materials and processing conditions for CDC synthesis at temperatures as low as 200°C, resulting in amorphous and highly reactive porous carbons. We also investigated synthesis of monolithic CDC films from carbide films at 250-1200°C. The results of our early studies provided new insights into CDC formation, led to development of materials for capacitive energy storage, and enabled fundamental understanding of the electrolyte ions confinement in nanoporous carbons.

  17. New insights into designing metallacarborane based room temperature hydrogen storage media.

    Science.gov (United States)

    Bora, Pankaj Lochan; Singh, Abhishek K

    2013-10-28

    Metallacarboranes are promising towards realizing room temperature hydrogen storage media because of the presence of both transition metal and carbon atoms. In metallacarborane clusters, the transition metal adsorbs hydrogen molecules and carbon can link these clusters to form metal organic framework, which can serve as a complete storage medium. Using first principles density functional calculations, we chalk out the underlying principles of designing an efficient metallacarborane based hydrogen storage media. The storage capacity of hydrogen depends upon the number of available transition metal d-orbitals, number of carbons, and dopant atoms in the cluster. These factors control the amount of charge transfer from metal to the cluster, thereby affecting the number of adsorbed hydrogen molecules. This correlation between the charge transfer and storage capacity is general in nature, and can be applied to designing efficient hydrogen storage systems. Following this strategy, a search for the best metallacarborane was carried out in which Sc based monocarborane was found to be the most promising H2 sorbent material with a 9 wt.% of reversible storage at ambient pressure and temperature.

  18. Water loss at normal enamel histological points during air drying at room temperature.

    Science.gov (United States)

    De Medeiros, R C G; De Lima, T A S; Gouveia, C R; De Sousa, F B

    2013-06-01

    This in vitro study aimed to quantify water loss at histological points in ground sections of normal enamel during air drying at room temperature (25°C) and relative humidity of 50%. From each of 10 ground sections of erupted permanent human normal enamel, three histological points (n = 30) located at 100, 300 and 500 μm from enamel surface and along a transversal following prisms paths were characterized regarding the mineral, organic and water volumes. Water loss during air drying was from 0 to 48 h. Drying occurred with both falling and constant-drying rates, and drying stabilization times (Teq ) ranged from 0.5 to 11 h with a mean 0.26 (±0.12)% weight loss. In some samples (n = 5; 15 points), Teq increased as a function of the distance from the enamel surface, and drying occurred at an apparent diffusion rate of 3.47 × 10⁻⁸ cm² s⁻¹. Our data provide evidence of air drying resulting in air replacing enamel's loosely bound water in prisms sheaths following a unidirectional water diffusion rate of 3.47 × 10⁻⁸ cm² s⁻¹ (from the original enamel surface inward), not necessarily resulting in water evaporating directly into air, with important implications for transport processes and optical and mechanical properties. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  19. Healable, Transparent, Room-Temperature Electronic Sensors Based on Carbon Nanotube Network-Coated Polyelectrolyte Multilayers.

    Science.gov (United States)

    Bai, Shouli; Sun, Chaozheng; Yan, Hong; Sun, Xiaoming; Zhang, Han; Luo, Liang; Lei, Xiaodong; Wan, Pengbo; Chen, Xiaodong

    2015-11-18

    Transparent and conductive film based electronics have attracted substantial research interest in various wearable and integrated display devices in recent years. The breakdown of transparent electronics prompts the development of transparent electronics integrated with healability. A healable transparent chemical gas sensor device is assembled from layer-by-layer-assembled transparent healable polyelectrolyte multilayer films by developing effective methods to cast transparent carbon nanotube (CNT) networks on healable substrates. The healable CNT network-containing film with transparency and superior network structures on self-healing substrate is obtained by the lateral movement of the underlying self-healing layer to bring the separated areas of the CNT layer back into contact. The as-prepared healable transparent film is assembled into healable transparent chemical gas sensor device for flexible, healable gas sensing at room temperature, due to the 1D confined network structure, relatively high carrier mobility, and large surface-to-volume ratio. The healable transparent chemical gas sensor demonstrates excellent sensing performance, robust healability, reliable flexibility, and good transparency, providing promising opportunities for developing flexible, healable transparent optoelectronic devices with the reduced raw material consumption, decreased maintenance costs, improved lifetime, and robust functional reliability. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Novel spintronics devices for memory and logic: prospects and challenges for room temperature all spin computing

    Science.gov (United States)

    Wang, Jian-Ping

    An energy efficient memory and logic device for the post-CMOS era has been the goal of a variety of research fields. The limits of scaling, which we expect to reach by the year 2025, demand that future advances in computational power will not be realized from ever-shrinking device sizes, but rather by innovative designs and new materials and physics. Magnetoresistive based devices have been a promising candidate for future integrated magnetic computation because of its unique non-volatility and functionalities. The application of perpendicular magnetic anisotropy for potential STT-RAM application was demonstrated and later has been intensively investigated by both academia and industry groups, but there is no clear path way how scaling will eventually work for both memory and logic applications. One of main reasons is that there is no demonstrated material stack candidate that could lead to a scaling scheme down to sub 10 nm. Another challenge for the usage of magnetoresistive based devices for logic application is its available switching speed and writing energy. Although a good progress has been made to demonstrate the fast switching of a thermally stable magnetic tunnel junction (MTJ) down to 165 ps, it is still several times slower than its CMOS counterpart. In this talk, I will review the recent progress by my research group and my C-SPIN colleagues, then discuss the opportunities, challenges and some potential path ways for magnetoresitive based devices for memory and logic applications and their integration for room temperature all spin computing system.

  1. Instant synthesis of gold nanoparticles at room temperature and SERS applications

    International Nuclear Information System (INIS)

    Britto Hurtado, R.; Cortez-Valadez, M.; Ramírez-Rodríguez, L.P.; Larios-Rodriguez, Eduardo; Alvarez, Ramón A.B.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C.E.; Arizpe-Chávez, H.; Hernández-Martínez, A.R.; Flores-Acosta, M.

    2016-01-01

    Nowadays, gold nanoparticles (AuNps) can be used in a variety of applications, thus efficient methods to produce them are necessary. Several methods have been proposed in this area, but NPs production time is one limitation of these approaches. In this study, we propose a high competitive method to synthesize gold colloidal nanoparticles, instantaneously, using no-toxic reducing agents. These substances allow the instantaneous synthesis at room temperature, even without magnetic stirrers, ovens or ultrasonic baths. Optic analysis showed two absorption bands, associated with surface Plasmon as function of HAuCl_4 concentration. The nanoparticles synthesized have a 10–20 nm size, seen by the transmission electron microscopy (TEM). Therefore, it was possible to obtain several geometric patterns of AuNps, and the synthesis was performed reducing significantly processing time. Additionally, Mie and Fuchs theories were used to predict the location of the absorption bands linked to the plasmon surface in gold nanoparticles. The Surface Enhanced Raman Spectroscopy (SERS) effect was analyzed considering natural zeolite (Chabazite) as analyte, in order to determinate its possible application in soil analysis. - Highlights: • Cubic and spherical morphologies in AuNp. • Surface plasmon prediction in cubic and spherical AuNp. • Instant synthesis of AuNp. • SERS applications in soil analysis.

  2. Facile fabrication of CNT-based chemical sensor operating at room temperature

    Science.gov (United States)

    Sheng, Jiadong; Zeng, Xian; Zhu, Qi; Yang, Zhaohui; Zhang, Xiaohua

    2017-12-01

    This paper describes a simple, low cost and effective route to fabricate CNT-based chemical sensors, which operate at room temperature. Firstly, the incorporation of silk fibroin in vertically aligned CNT arrays (CNTA) obtained through a thermal chemical vapor deposition (CVD) method makes the direct removal of CNT arrays from substrates without any rigorous acid or sonication treatment feasible. Through a simple one-step in situ polymerization of anilines, the functionalization of CNT arrays with polyaniline (PANI) significantly improves the sensing performance of CNT-based chemical sensors in detecting ammonia (NH3) and hydrogen chloride (HCl) vapors. Chemically modified CNT arrays also show responses to organic vapors like menthol, ethyl acetate and acetone. Although the detection limits of chemically modified CNT-based chemical sensors are of the same orders of magnitudes reported in previous studies, these CNT-based chemical sensors show advantages of simplicity, low cost and energy efficiency in preparation and fabrication of devices. Additionally, a linear relationship between the relative sensitivity and concentration of analyte makes precise estimations on the concentrations of trace chemical vapors possible.

  3. Room temperature X- and gamma-ray detectors using thallium bromide crystals

    CERN Document Server

    Hitomi, K; Shoji, T; Suehiro, T; Hiratate, Y

    1999-01-01

    Thallium bromide (TlBr) is a compound semiconductor with wide band gap (2.68 eV) and high X- and gamma-ray stopping power. The TlBr crystals were grown by the horizontal travelling molten zone (TMZ) method using purified material. Two types of room temperature X- and gamma-ray detectors were fabricated from the TlBr crystals: TlBr detectors with high detection efficiency for positron annihilation gamma-ray (511 keV) detection and TlBr detectors with high-energy resolution for low-energy X-ray detection. The detector of the former type demonstrated energy resolution of 56 keV FWHM (11%) for 511 keV gamma-rays. Energy resolution of 1.81 keV FWHM for 5.9 keV was obtained from the detector of the latter type. In order to analyze noise characteristics of the detector-preamplifier assembly, the equivalent noise charge (ENC) was measured as a function of the amplifier shaping time for the high-resolution detector. This analysis shows that parallel white noise and 1/f noise were dominant noise sources in the detector...

  4. Room-Temperature Synthesis of Thiostannates from {[Ni(tren)]2[Sn2S6]}n.

    Science.gov (United States)

    Hilbert, Jessica; Näther, Christian; Weihrich, Richard; Bensch, Wolfgang

    2016-08-15

    The compound {[Ni(tren)]2[Sn2S6]}n (1) (tren = tris(2-aminoethyl)amine, C6H18N4) was successfully applied as source for the room-temperature synthesis of the new thiostannates [Ni(tren)(ma)(H2O)]2[Sn2S6]·4H2O (2) (ma = methylamine, CH5N) and [Ni(tren)(1,2-dap)]2[Sn2S6]·2H2O (3) (1,2-dap = 1,2-diaminopropane, C3H10N2). The Ni-S bonds in the Ni2S2N8 bioctahedron in the structure of 1 are analyzed with density functional theory calculations demonstrating significantly differing Ni-S bond strengths. Because of this asymmetry they are easily broken in the presence of an excess of ma or 1,2-dap immediately followed by Ni-N bond formation to N donor atoms of the amine ligands thus generating [Ni(tren)(amine)](2+) complexes. The chemical reactions are fast, and compounds 2 and 3 are formed within 1 h. The synthesis concept presented here opens hitherto unknown possibilities for preparation of new thiostannates.

  5. Photoinduced, copper-catalyzed alkylation of amides with unactivated secondary alkyl halides at room temperature.

    Science.gov (United States)

    Do, Hien-Quang; Bachman, Shoshana; Bissember, Alex C; Peters, Jonas C; Fu, Gregory C

    2014-02-05

    The development of a mild and general method for the alkylation of amides with relatively unreactive alkyl halides (i.e., poor substrates for SN2 reactions) is an ongoing challenge in organic synthesis. We describe herein a versatile transition-metal-catalyzed approach: in particular, a photoinduced, copper-catalyzed monoalkylation of primary amides. A broad array of alkyl and aryl amides (as well as a lactam and a 2-oxazolidinone) couple with unactivated secondary (and hindered primary) alkyl bromides and iodides using a single set of comparatively simple and mild conditions: inexpensive CuI as the catalyst, no separate added ligand, and C-N bond formation at room temperature. The method is compatible with a variety of functional groups, such as an olefin, a carbamate, a thiophene, and a pyridine, and it has been applied to the synthesis of an opioid receptor antagonist. A range of mechanistic observations, including reactivity and stereochemical studies, are consistent with a coupling pathway that includes photoexcitation of a copper-amidate complex, followed by electron transfer to form an alkyl radical.

  6. Nanosecond time-resolved characterization of a pentacene-based room-temperature MASER

    Science.gov (United States)

    Salvadori, Enrico; Breeze, Jonathan D.; Tan, Ke-Jie; Sathian, Juna; Richards, Benjamin; Fung, Mei Wai; Wolfowicz, Gary; Oxborrow, Mark; Alford, Neil McN.; Kay, Christopher W. M.

    2017-01-01

    The performance of a room temperature, zero-field MASER operating at 1.45 GHz has been examined. Nanosecond laser pulses, which are essentially instantaneous on the timescale of the spin dynamics, allow the visible-to-microwave conversion efficiency and temporal response of the MASER to be measured as a function of excitation energy. It is observed that the timing and amplitude of the MASER output pulse are correlated with the laser excitation energy: at higher laser energy, the microwave pulses have larger amplitude and appear after shorter delay than those recorded at lower laser energy. Seeding experiments demonstrate that the output variation may be stabilized by an external source and establish the minimum seeding power required. The dynamics of the MASER emission may be modeled by a pair of first order, non-linear differential equations, derived from the Lotka-Volterra model (Predator-Prey), where by the microwave mode of the resonator is the predator and the spin polarization in the triplet state of pentacene is the prey. Simulations allowed the Einstein coefficient of stimulated emission, the spin-lattice relaxation and the number of triplets contributing to the MASER emission to be estimated. These are essential parameters for the rational improvement of a MASER based on a spin-polarized triplet molecule. PMID:28169331

  7. Reciprocating sliding wear of Inconel 600 tubing in room temperature air

    International Nuclear Information System (INIS)

    Kim, Hun; Choi, Jong Hyun; Kim, Jun Ki; Hong, Hyun Seon; Kim, Seon Jin

    2003-01-01

    The sliding wear behavior of the material of a steam generator in a nuclear power station (Inconel 600) was investigated at room temperature. Effects of the wear parameters such as material combination, sliding distance and contact stress were examined with various mating materials including 304 austenitic stainless steel, Inconel 600 and Al-Cu alloy 2011. In the prediction of the wear volume by Archard's wear equation, the standard error range was calculated to be ±4.04x10 -9 m 3 and the reliability to be 71.9% for the combination of Inconel 600 and 304 stainless steel. The error range was considered to be relatively broad because the wear coefficient in Archard's equation was assumed to be a constant, regardless of the changes in the mechanical properties during the wear. In the present study, the sliding wear behavior turned out to be influenced by the material combination; the wear volume of 304 stainless steel did not linearly increase with the sliding distance, while that of other material combinations exhibited linear increases. Based on the experimental results, the wear coefficient was modified as a function of the sliding distance. The calculation with the modified wear equation showed that the error range narrowed down to ±2.60x10 -9 m 3 and the reliability increased to 75.3%, compared to Archard's original equation

  8. Room-temperature luminescence decay of colloidal semiconductor quantum dots: Nonexponentiality revisited

    Energy Technology Data Exchange (ETDEWEB)

    Bodunov, Evgeny N. [Department of Physics, Petersburg State Transport University, St. Petersburg (Russian Federation); Danilov, Vladimir V. [Department of Physics, Petersburg State Transport University, St. Petersburg (Russian Federation); Vavilov State Optical Institute, St. Petersburg (Russian Federation); Panfutova, Anastasia S. [Vavilov State Optical Institute, St. Petersburg (Russian Federation); Simoes Gamboa, A.L. [Center of Information Optical Technologies, ITMO University, St. Petersburg (Russian Federation)

    2016-04-15

    While time-resolved luminescence spectroscopy is commonly used as a quantitative tool for the analysis of the dynamics of photoexcitation in colloidal semiconductor quantum dots, the interpretation of the virtually ubiquitous nonexponential decay profiles is frequently ambiguous, because the assumption of multiple discrete exponential components with distinct lifetimes for resolving the decays is often arbitrary. Here, an interpretation of the room-temperature luminescence decay of CdSe/ZnS semiconductor quantum dots in colloidal solutions is presented based on the Kohlrausch relaxation function. It is proposed that the decay can be understood by using the concept of Foerster resonance energy transfer (FRET) assuming that the role of acceptors of photoexcitation energy is played by high-frequency anharmonic molecular vibrations in the environment of the quantum dots. The term EVFRET (Electronic - Vibrational Foerster Resonance Energy Transfer) is introduced in order to unequivocally refer to this energy transfer process. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Instant synthesis of gold nanoparticles at room temperature and SERS applications

    Energy Technology Data Exchange (ETDEWEB)

    Britto Hurtado, R. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Cortez-Valadez, M., E-mail: jose.cortez@unison.mx [CONACYT-Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Ramírez-Rodríguez, L.P. [Departamento de Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Larios-Rodriguez, Eduardo [Departamento de Ingeniería Química y Metalurgia, Universidad de Sonora, Rosales y Luis Encinas S/N, Hermosillo, Sonora (Mexico); Alvarez, Ramón A.B.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C.E.; Arizpe-Chávez, H. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Hernández-Martínez, A.R. [Centro de Física Aplicada y Tecnología Avanzada (CFATA), Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro C.P. 76130 (Mexico); Flores-Acosta, M. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico)

    2016-08-06

    Nowadays, gold nanoparticles (AuNps) can be used in a variety of applications, thus efficient methods to produce them are necessary. Several methods have been proposed in this area, but NPs production time is one limitation of these approaches. In this study, we propose a high competitive method to synthesize gold colloidal nanoparticles, instantaneously, using no-toxic reducing agents. These substances allow the instantaneous synthesis at room temperature, even without magnetic stirrers, ovens or ultrasonic baths. Optic analysis showed two absorption bands, associated with surface Plasmon as function of HAuCl{sub 4} concentration. The nanoparticles synthesized have a 10–20 nm size, seen by the transmission electron microscopy (TEM). Therefore, it was possible to obtain several geometric patterns of AuNps, and the synthesis was performed reducing significantly processing time. Additionally, Mie and Fuchs theories were used to predict the location of the absorption bands linked to the plasmon surface in gold nanoparticles. The Surface Enhanced Raman Spectroscopy (SERS) effect was analyzed considering natural zeolite (Chabazite) as analyte, in order to determinate its possible application in soil analysis. - Highlights: • Cubic and spherical morphologies in AuNp. • Surface plasmon prediction in cubic and spherical AuNp. • Instant synthesis of AuNp. • SERS applications in soil analysis.

  10. Impacts of exhalation flow on the microenvironment around the human body under different room temperatures

    Science.gov (United States)

    Jafari, Mohammad Javad; Gharari, Noradin; Azari, Mansour Rezazade; Ashrafi, Khosro

    2018-04-01

    Exhalation flow and room temperature can have a considerable effect on the microenvironment in the vicinity of human body. In this study, impacts of exhalation flow and room temperature on the microenvironment around a human body were investigated using a numerical simulation. For this purpose, a computational fluid dynamic program was applied to study thermal plume around a sitting human body at different room temperatures of a calm indoor room by considering the exhalation flow. The simulation was supported by some experimental measurements. Six different room temperatures (18 to 28 °C) with two nose exhalation modes (exhalation and non-exhalation) were investigated. Overhead and breathing zone velocities and temperatures were simulated in different scenarios. This study finds out that the exhalation through the nose has a significant impact on both quantitative and qualitative features of the human microenvironment in different room temperatures. At a given temperature, the exhalation through the nose can change the location and size of maximum velocity at the top of the head. In the breathing zone, the effect of exhalation through the nose on velocity and temperature distribution was pronounced for the point close to mouth. Also, the exhalation through the nose strongly influences the thermal boundary layer on the breathing zone while it only minimally influences the convective boundary layer on the breathing zone. Overall results demonstrate that it is important to take the exhalation flow into consideration in all areas, especially at a quiescent flow condition with low temperature.

  11. Possible room temperature superconductivity in conductors obtained by bringing alkanes into contact with a graphite surface

    Directory of Open Access Journals (Sweden)

    Yasushi Kawashima

    2013-05-01

    Full Text Available Electrical resistances of conductors obtained by bringing alkanes into contact with a graphite surface have been investigated at room temperatures. Ring current in a ring-shaped container into which n-octane-soaked thin graphite flakes were compressed did not decay for 50 days at room temperature. After two HOPG plates were immersed into n-heptane and n-octane at room temperature, changes in resistances of the two samples were measured by four terminal technique. The measurement showed that the resistances of these samples decrease to less than the smallest resistance that can be measured with a high resolution digital voltmeter (0.1μV. The observation of persistent currents in the ring-shaped container suggests that the HOPG plates immersed in n-heptane and n-octane really entered zero-resistance state at room temperature. These results suggest that room temperature superconductor may be obtained by bringing alkanes into contact with a graphite surface.

  12. Dielectric relaxations above room temperature in DMPU derived polyaniline film

    International Nuclear Information System (INIS)

    Mallya, Ashwini N.; Yashavanth Kumar, G.S.; Ranjan, Rajeev; Ramamurthy, Praveen C.

    2012-01-01

    Dielectric measurements carried out on drop casted from solution of emeraldine base form of polyaniline films in the temperature range 30-300 °C revealed occurrence of two maxima in the loss tangent as a function of temperature. The activation energies corresponding to these two relaxation processes were found to be ∼0.5 eV and ∼1.5 eV. The occurrence of one relaxation peak in the dispersion curve of the imaginary part of the electric modulus suggests the absence of microphase separation in the film. Thermogravimetric analysis and infrared spectroscopic measurements showed that the films retained its integrity up to 300 °C. The dielectric relaxation at higher temperatures with large activation energy of 1.5 eV is attributed to increase in the barrier potential due to decrease in the polymer conjugation as a result of wide amplitude motion of the chain segments well above the glass transition temperature.

  13. Room temperature photoinduced magnetism in [py.H]{sub 3}[FeCl{sub 4}]{sub 2}Cl

    Energy Technology Data Exchange (ETDEWEB)

    Baniasadi, F. [Physics Department, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Tehranchi, M.M., E-mail: teranchi@sbu.ac.ir [Physics Department, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Fathi, M.B. [Physics Department, Kharazmi University, Tehran (Iran, Islamic Republic of); Hamidi, S.M. [Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Safari, N.; Amani, V. [Faculty of Chemistry, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2015-11-15

    Photoinduced magnetism in a homogeneous solution of [py.H]{sub 3}[FeCl{sub 4}]{sub 2}Cl is measured by Faraday rotation in visible light (λ∼450–750 nm) at room temperature. The physics of this phenomenon may be attributed to electronic transitions caused by absorption of light. X-ray diffraction and Debye function analysis are therefore applied to find the abundant unit of molecules dissolved in the solution which are being further utilized to investigate the electronic structure and molecular orbitals by means of hybrid density function theory (B3LYP). Faraday rotation is observed at certain wavelengths consistent with energy differences of HOMO-LUMO energy levels. Thus this work puts forward a new material with certain photomagnetic properties which may be used in fabrication of room temperature magneto-optical switches. - Highlights: • Photoinduced magnetism in (FeCl{sub 4}){sub 2}(py.H){sub 3}Cl is illustrated via Faraday rotation. • The abundant unit of molecule is characterized by Debye function analysis of XRD. • PIM in the molecule is attributed to the charge transfer between HOMO-LUMO.

  14. Dielectric relaxations above room temperature in DMPU derived polyaniline film

    Energy Technology Data Exchange (ETDEWEB)

    Mallya, Ashwini N.; Yashavanth Kumar, G.S.; Ranjan, Rajeev [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Ramamurthy, Praveen C., E-mail: onegroupb203@gmail.com [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2012-09-15

    Dielectric measurements carried out on drop casted from solution of emeraldine base form of polyaniline films in the temperature range 30-300 Degree-Sign C revealed occurrence of two maxima in the loss tangent as a function of temperature. The activation energies corresponding to these two relaxation processes were found to be {approx}0.5 eV and {approx}1.5 eV. The occurrence of one relaxation peak in the dispersion curve of the imaginary part of the electric modulus suggests the absence of microphase separation in the film. Thermogravimetric analysis and infrared spectroscopic measurements showed that the films retained its integrity up to 300 Degree-Sign C. The dielectric relaxation at higher temperatures with large activation energy of 1.5 eV is attributed to increase in the barrier potential due to decrease in the polymer conjugation as a result of wide amplitude motion of the chain segments well above the glass transition temperature.

  15. Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

    Science.gov (United States)

    Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

    2018-05-01

    Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

  16. Glass Transitions and Low-Frequency Dynamics of Room-Temperature Ionic Liquids

    International Nuclear Information System (INIS)

    Yamamuro, O.; Inamura, Y.; Hayashi, S.; Hamaguchi, H.

    2006-01-01

    We have measured the heat capacity and neutrion quasi- and inelastic scattering spectra of some salts of 1-butyl-3-methylimidazolium ion bmim+, which is a typical cation of room-temperature ionic liquids, and its derivatives. The heat capacity measurements revealed that the room-temperature ionic liquids have glass transitions as molecular liquids. The temperature dependence of configurational entropy demonstrated that the room-temperature ionic liquids are 'fragile liquids'. Both heat capacity and inelastic neutron scattering data revealed that the glassy phases exhibit large low-energy excitations usually called 'boson peak'. The quasielastic neutron scattering data showed that so-called 'fast process' appears around Tg as in molecular and polymer glasses. The temperature dependence of the self-diffusion coefficient derived from the neutron scattering data indicated that the orientation of bmim+ ions and/or butyl-groups of bmim+ ions is highly disordered and very flexible in an ionic liquid phase

  17. Direct writing of room temperature and zero field skyrmion lattices by a scanning local magnetic field

    KAUST Repository

    Zhang, Senfu; Zhang, Junwei; Zhang, Qiang; Barton, Craig; Neu, Volker; Zhao, Yuelei; Hou, Zhipeng; Wen, Yan; Gong, Chen; Kazakova, Olga; Wang, Wenhong; Peng, Yong; Garanin, Dmitry A.; Chudnovsky, Eugene M.; Zhang, Xixiang

    2018-01-01

    Magnetic skyrmions are topologically protected nanoscale spin textures exhibiting fascinating physical behaviors. Recent observations of room temperature skyrmions in sputtered multilayer films are an important step towards their use in ultra-low power devices. Such practical applications prefer skyrmions to be stable at zero magnetic fields and room temperature. Here, we report the creation of skyrmion lattices in Pt/Co/Ta multilayers by a scanning local field using magnetic force microscopy tips. We also show that those newly created skyrmion lattices are stable at both room temperature and zero fields. Lorentz transmission electron microscopy measurements reveal that the skyrmions in our films are of Néel-type. To gain a deeper understanding of the mechanism behind the creation of a skyrmion lattice by the scanning of local fields, we perform micromagnetic simulations and find the experimental results to be in agreement with our simulation data. This study opens another avenue for the creation of skyrmion lattices in thin films.

  18. Direct writing of room temperature and zero field skyrmion lattices by a scanning local magnetic field

    Science.gov (United States)

    Zhang, Senfu; Zhang, Junwei; Zhang, Qiang; Barton, Craig; Neu, Volker; Zhao, Yuelei; Hou, Zhipeng; Wen, Yan; Gong, Chen; Kazakova, Olga; Wang, Wenhong; Peng, Yong; Garanin, Dmitry A.; Chudnovsky, Eugene M.; Zhang, Xixiang

    2018-03-01

    Magnetic skyrmions are topologically protected nanoscale spin textures exhibiting fascinating physical behaviors. Recent observations of room temperature skyrmions in sputtered multilayer films are an important step towards their use in ultra-low power devices. Such practical applications prefer skyrmions to be stable at zero magnetic fields and room temperature. Here, we report the creation of skyrmion lattices in Pt/Co/Ta multilayers by a scanning local field using magnetic force microscopy tips. We also show that those newly created skyrmion lattices are stable at both room temperature and zero fields. Lorentz transmission electron microscopy measurements reveal that the skyrmions in our films are of Néel-type. To gain a deeper understanding of the mechanism behind the creation of a skyrmion lattice by the scanning of local fields, we perform micromagnetic simulations and find the experimental results to be in agreement with our simulation data. This study opens another avenue for the creation of skyrmion lattices in thin films.

  19. Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

    Science.gov (United States)

    Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

    2018-03-01

    Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

  20. Room-temperature spin-polarized organic light-emitting diodes with a single ferromagnetic electrode

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Baofu, E-mail: b.ding@ecu.edu.au; Alameh, Kamal, E-mail: k.alameh@ecu.edu.au [Electron Science Research Institute, Edith Cowan University, 270 Joondalup Drive, Joondalup WA 6027 Australia (Australia); Song, Qunliang [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China)

    2014-05-19

    In this paper, we demonstrate the concept of a room-temperature spin-polarized organic light-emitting diode (Spin-OLED) structure based on (i) the deposition of an ultra-thin p-type organic buffer layer on the surface of the ferromagnetic electrode of the Spin-OLED and (ii) the use of oxygen plasma treatment to modify the surface of that electrode. Experimental results demonstrate that the brightness of the developed Spin-OLED can be increased by 110% and that a magneto-electroluminescence of 12% can be attained for a 150 mT in-plane magnetic field, at room temperature. This is attributed to enhanced hole and room-temperature spin-polarized injection from the ferromagnetic electrode, respectively.

  1. Direct writing of room temperature and zero field skyrmion lattices by a scanning local magnetic field

    KAUST Repository

    Zhang, Senfu

    2018-03-29

    Magnetic skyrmions are topologically protected nanoscale spin textures exhibiting fascinating physical behaviors. Recent observations of room temperature skyrmions in sputtered multilayer films are an important step towards their use in ultra-low power devices. Such practical applications prefer skyrmions to be stable at zero magnetic fields and room temperature. Here, we report the creation of skyrmion lattices in Pt/Co/Ta multilayers by a scanning local field using magnetic force microscopy tips. We also show that those newly created skyrmion lattices are stable at both room temperature and zero fields. Lorentz transmission electron microscopy measurements reveal that the skyrmions in our films are of Néel-type. To gain a deeper understanding of the mechanism behind the creation of a skyrmion lattice by the scanning of local fields, we perform micromagnetic simulations and find the experimental results to be in agreement with our simulation data. This study opens another avenue for the creation of skyrmion lattices in thin films.

  2. A new sensor for ammonia based on cyanidin-sensitized titanium dioxide film operating at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Xiao-wei, Huang [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Xiao-bo, Zou, E-mail: zou_xiaobo@ujs.edu.cn [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Key Laboratory of Modern Agricultural Equipment and Technology, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Ji-yong, Shi; Jie-wen, Zhao; Yanxiao, Li [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Limin, Hao; Jianchun, Zhang [The Research Center of China Hemp Materials, Beijing (China)

    2013-07-17

    Graphical abstract: -- Highlights: •TiO{sub 2} was prepared by sol–gel method film and then functionalized with the cyanidin dye. •The morphology and the absorption spectra of films were examined. •The hybrid organic–inorganic formed film here can detect ammonia reversibly at room temperature. •The low humidity could promote the sensitivity of the sensors. -- Abstract: Design and fabrication of an ammonia sensor operating at room temperature based on pigment-sensitized TiO{sub 2} films was described. TiO{sub 2} was prepared by sol–gel method and deposited on glass slides containing gold electrodes. Then, the film immersed in a 2.5 × 10{sup −4} M ethanol solution of cyanidin to absorb the pigment. The hybrid organic–inorganic formed film here can detect ammonia reversibly at room temperature. The relative change resistance of the films at a potential difference of 1.5 V is determined when the films are exposed to atmospheres containing ammonia vapors with concentrations over the range 10–50 ppm. The relative change resistance, S, of the films increased almost linearly with increasing concentrations of ammonia (r = 0.92). The response time to increasing concentrations of the ammonia is about 180–220 s, and the corresponding values for decreasing concentrations 240–270 s. At low humidity, ammonia could be ionized by the cyanidin on the TiO{sub 2} film and thereby decrease in the proton concentration at the surface. Consequently, more positively charged holes at the surface of the TiO{sub 2} have to be extracted to neutralize the adsorbed cyanidin and water film. The resistance response to ammonia of the sensors was nearly independent on temperature from 10 to 50 °C. These results are not actually as good as those reported in the literature, but this preliminary work proposes simpler and cheaper processes to realize NH{sub 3} sensor for room temperature applications.

  3. Defect types and room-temperature ferromagnetism in undoped rutile TiO2 single crystals

    Science.gov (United States)

    Li, Dong-Xiang; Qin, Xiu-Bo; Zheng, Li-Rong; Li, Yu-Xiao; Cao, Xing-Zhong; Li, Zhuo-Xin; Yang, Jing; Wang, Bao-Yi

    2013-03-01

    Room-temperature ferromagnetism has been experimentally observed in annealed rutile TiO2 single crystals when a magnetic field is applied parallel to the sample plane. By combining X-ray absorption near the edge structure spectrum and positron annihilation lifetime spectroscopy, Ti3+—VO defect complexes (or clusters) have been identified in annealed crystals at a high vacuum. We elucidate that the unpaired 3d electrons in Ti3+ ions provide the observed room-temperature ferromagnetism. In addition, excess oxygen ions in the TiO2 lattice could induce a number of Ti vacancies which obviously increase magnetic moments.

  4. CeBr3 as a room-temperature, high-resolution gamma-ray detector

    International Nuclear Information System (INIS)

    Guss, Paul; Reed, Michael; Yuan Ding; Reed, Alexis; Mukhopadhyay, Sanjoy

    2009-01-01

    Cerium bromide (CeBr 3 ) has become a material of interest in the race for high-resolution gamma-ray spectroscopy at room temperature. This investigation quantified the potential of CeBr 3 as a room-temperature, high-resolution gamma-ray detector. The performance of CeBr 3 crystals was compared to other scintillation crystals of similar dimensions and detection environments. Comparison of self-activity of CeBr 3 to cerium-doped lanthanum tribromide (LaBr 3 :Ce) was performed. Energy resolution and relative intrinsic efficiency were measured and are presented.

  5. Multiwalled carbon nanotubes sensor for organic liquid detection at room temperature

    Science.gov (United States)

    Chaudhary, Deepti; Khare, Neeraj; Vankar, V. D.

    2016-04-01

    We have explored the possibility of using multiwalled carbon nanotubes (MWCNTs) as room temperature chemical sensor for the detection of organic liquids such as ethanol, propanol, methanol and toluene. MWCNTs were synthesized by thermal chemical vapor deposition (TCVD) technique. The interdigitated electrodes were fabricated by conventional photolithography technique. The sensor was fabricated by drop depositing MWCNT suspension onto the interdigitated electrodes. The sensing properties of MWCNTs sensor was studied for organic liquids detection. The resistance of sensor was found to increase upon exposure to these liquids. Sensor shows good reversibility and fast response at room temperature. Charge transfer between the organic liquid and sensing element is the dominant sensing mechanism.

  6. Photoexcited Individual Nanowires: Key Elements in Room Temperature Detection of Oxidizing Gases

    International Nuclear Information System (INIS)

    Prades, J. D.; Jimenez-Diaz, R.; Manzanares, M.; Andreu, T.; Cirera, A.; Romano-Rodriguez, A.; Hernandez-Ramirez, F.; Morante, J. R.

    2009-01-01

    Illuminating metal oxide semiconductors with ultra-violet light is a feasible alternative to activate chemical reactions at their surface and thus, using them as gas sensors without the necessity of heating them. Here, the response at room temperature of individual single-crystalline SnO 2 nanowires towards NO 2 is studied in detail. The results reveal that similar responses to those obtained with thermally activated sensors can be achieved by choosing the optimal illumination conditions. This finding paves the way to the development of conductometric gas sensors operated at room temperature. The power consumption in these devices is in range with conventional micromachined sensors.

  7. Quantum confinement of zero-dimensional hybrid organic-inorganic polaritons at room temperature

    Science.gov (United States)

    Nguyen, H. S.; Han, Z.; Abdel-Baki, K.; Lafosse, X.; Amo, A.; Lauret, J.-S.; Deleporte, E.; Bouchoule, S.; Bloch, J.

    2014-02-01

    We report on the quantum confinement of zero-dimensional polaritons in perovskite-based microcavity at room temperature. Photoluminescence of discrete polaritonic states is observed for polaritons localized in symmetric sphere-like defects which are spontaneously nucleated on the top dielectric Bragg mirror. The linewidth of these confined states is found much sharper (almost one order of magnitude) than that of photonic modes in the perovskite planar microcavity. Our results show the possibility to study organic-inorganic cavity polaritons in confined microstructure and suggest a fabrication method to realize integrated polaritonic devices operating at room temperature.

  8. Quantum confinement of zero-dimensional hybrid organic-inorganic polaritons at room temperature

    International Nuclear Information System (INIS)

    Nguyen, H. S.; Lafosse, X.; Amo, A.; Bouchoule, S.; Bloch, J.; Han, Z.; Abdel-Baki, K.; Lauret, J.-S.; Deleporte, E.

    2014-01-01

    We report on the quantum confinement of zero-dimensional polaritons in perovskite-based microcavity at room temperature. Photoluminescence of discrete polaritonic states is observed for polaritons localized in symmetric sphere-like defects which are spontaneously nucleated on the top dielectric Bragg mirror. The linewidth of these confined states is found much sharper (almost one order of magnitude) than that of photonic modes in the perovskite planar microcavity. Our results show the possibility to study organic-inorganic cavity polaritons in confined microstructure and suggest a fabrication method to realize integrated polaritonic devices operating at room temperature

  9. Defect types and room-temperature ferromagnetism in undoped rutile TiO2 single crystals

    International Nuclear Information System (INIS)

    Li Dong-Xiang; Cao Xing-Zhong; Li Zhuo-Xin; Yang Jing; Wang Bao-Yi; Qin Xiu-Bo; Zheng Li-Rong; Li Yu-Xiao

    2013-01-01

    Room-temperature ferromagnetism has been experimentally observed in annealed rutile TiO 2 single crystals when a magnetic field is applied parallel to the sample plane. By combining X-ray absorption near the edge structure spectrum and positron annihilation lifetime spectroscopy, Ti 3+ —V O defect complexes (or clusters) have been identified in annealed crystals at a high vacuum. We elucidate that the unpaired 3d electrons in Ti 3+ ions provide the observed room-temperature ferromagnetism. In addition, excess oxygen ions in the TiO 2 lattice could induce a number of Ti vacancies which obviously increase magnetic moments

  10. Room-Temperature Synthesis of Transition Metal Clusters and Main Group Polycations from Ionic Liquids

    OpenAIRE

    Ahmed, Ejaz

    2011-01-01

    Main group polycations and transition metal clusters had traditionally been synthesized via high-temperature routes by performing reactions in melts or by CTR, at room-temperature or lower temperature by using so-called superacid solvents, and at room-temperature in benzene–GaX3 media. Considering the major problems associated with higher temperature routes (e.g. long annealing time, risk of product decomposition, and low yield) and taking into account the toxicity of benzene and liquid SO2 i...

  11. CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO_2 at room temperature

    International Nuclear Information System (INIS)

    Yu, B.; Yang, Z.Z.; Zhao, Y.F.; Zhang, H.Y.; Yang, P.; Gao, X.; Liu, Z.M.

    2017-01-01

    A CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO_2 in the presence of trimethylsilylacetylene was developed to give functionalized propiolic acid products at room temperature. A wide range of propiolic acids bearing functional groups was successfully obtained in good to excellent yields. Mechanistic studies demonstrate that in the carboxylation process the alkynyl-silane intermediate was first in situ generated, which was then trapped by CO_2, giving rise to the corresponding functionalized propiolic acids after acidification. The advantages of this approach include avoiding use of transition-metal catalysts, wide substrate scope together with excellent functional group tolerance, ambient conditions and a facile work-up procedure. (authors)

  12. Characterisation of cathodic arc evaporated CrTiAlN coatings: Tribological response at room temperature and at 400 °C

    Energy Technology Data Exchange (ETDEWEB)

    Georgiadis, Argyrios; Fuentes, Gonzalo G., E-mail: gfuentes@ain.es; Almandoz, Eluxka; Medrano, Angel; Palacio, José F.; Miguel, Adrián

    2017-04-01

    In this work, cathodic arc evaporation CrTiAlN coatings have been deposited on H13 hot work steel and the tribological behavior investigated at room temperature and at 400 °C. The microstructure, composition, roughness, indentation hardness and lattice parameter have been measured as a function of the deposition conditions, mainly given by the different Cr and TiAl vapour fluxes coming from the cathode arrangement in the vacuum reactor. The coating microstructures showed dense, compact columnar growth and a good film adhesion. The lattice parameter measured over the (002) diffraction peaks exhibited a quasi lineal correlation with the Ti/Cr+Al atomic ratio of the samples. In addition, the indentation hardness also increased as the lattice parameter increased. The coefficients of friction unveiled the different tribological behavior of the samples depending on the stoichiomentry and the temperature. At 400 °C, the coefficients of friction showed high dispersion, in contrast to the coherent evolution observed at room temperature. The wear damage at 400 °C was more intense than that observed at room temperature in agreement with the friction evolution observed. The coating with a stoichiometry of Cr{sub 0.23}Ti{sub 0.13}Al{sub 0.22}N{sub 0.42} showed a good wear performance at 400 °C. - Highlights: • CrTiAlN arc coatings deposited on hot work steel using different Cr and TiAl vapour fluxes. • Found correlation between Ti/Cr+Al atomic ratio, hardness and lattice parameters. • COF and wear show coherent evolution and low damage level at room temperature. • COF and wear at 400 °C exhibit higher level of damage than at room temperature. • Cr{sub 0.23}Ti{sub 0.13}Al{sub 0.22}N{sub 0.42} showed a good wear performance at 400 °C.

  13. The growth of manganese layers on Si(1 0 0) at room temperature: A photoelectron spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Nolph, C.A. [University of Virgina, Department of Materials Science and Engineering, 395 McCormick Road, Charlottesville, VA 22904 (United States); Vescovo, E. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Reinke, P., E-mail: pr6e@virginia.edu [University of Virgina, Department of Materials Science and Engineering, 395 McCormick Road, Charlottesville, VA 22904 (United States)

    2009-06-15

    The combination of spin-and charge based electronics in future devices requires the magnetic doping of group IV semiconductors, and the formation of ferromagnetic contacts. The doping of Mn with Si is one of the material systems which is discussed in this context. The present study focuses on the growth of Mn on a Si(100)(2x1) surface, and the evolution of the surface was observed as a function of Mn coverage with synchrotron-based photoelectron spectroscopy. The reaction of Mn with the Si(100) surface at room temperature leads the formation of silicide at the boundary between the Si substrate and the Mn-overlayer, presumably with MnSi stoichiometry. The residual sub-oxide reacts with the Mn and therefore incorporates a few percent of Mn-O-Si at the interface. The analysis of the sub-oxide composition indicates that the Si{sup +1} component is the most reactive oxidation state. The overlayer is dominated by Mn, either as Mn-metal or as a Mn-rich silicide phase, and the metallic layer introduces a band bending in Si. As a consequence of our observations, including information from a recent STM study, the formation of ferromagnetic contacts which require ideally a flat and compositionally homogenous overlayer, cannot be achieved through room temperature deposition of Mn on the Si(100) (2x1) surface. The influence of residual oxides and surface defects on the growth process will be further investigated.

  14. Effect of calcination temperature on formaldehyde oxidation performance of Pt/TiO2 nanofiber composite at room temperature

    Science.gov (United States)

    Xu, Feiyan; Le, Yao; Cheng, Bei; Jiang, Chuanjia

    2017-12-01

    Catalytic oxidation at room temperature over well-designed catalysts is an environmentally friendly method for the abatement of indoor formaldehyde (HCHO) pollution. Herein, nanocomposites of platinum (Pt) and titanium dioxide (TiO2) nanofibers with various phase compositions were prepared by calcining the electrospun TiO2 precursors at different temperatures and subsequently depositing Pt nanoparticles (NPs) on the TiO2 through a NaBH4-reduction process. The phase compositions and structures of Pt/TiO2 can be easily controlled by varying the calcination temperature. The Pt/TiO2 nanocomposites showed a phase-dependent activity towards the catalytic HCHO oxidation. Pt/TiO2 containing pure rutile phase showed enhanced activity with a turnover frequency (TOF) of 16.6 min-1 (for a calcination temperature of 800 °C) as compared to those containing the anatase phase or mixed phases. Density functional theory calculation shows that TiO2 nanofibers with pure rutile phase have stronger adsorption ability to Pt atoms than anatase phase, which favors the reduction of Pt over rutile phase TiO2, leading to higher contents of metallic Pt in the nanocomposite. In addition, the Pt/TiO2 with rutile phase possesses more abundant oxygen vacancies, which is conducive to the activation of adsorbed oxygen. Consequently, the Pt/rutile-TiO2 nanocomposite exhibited better catalytic activity towards HCHO oxidation at room temperature.

  15. Methanogenic degradation of toilet-paper cellulose upon sewage treatment in an anaerobic membrane bioreactor at room temperature.

    Science.gov (United States)

    Chen, Rong; Nie, Yulun; Kato, Hiroyuki; Wu, Jiang; Utashiro, Tetsuya; Lu, Jianbo; Yue, Shangchao; Jiang, Hongyu; Zhang, Lu; Li, Yu-You

    2017-03-01

    Toilet-paper cellulose with rich but refractory carbon sources, are the main insoluble COD fractions in sewage. An anaerobic membrane bioreactor (AnMBR) was configured for sewage treatment at room temperature and its performance on methanogenic degradation of toilet paper was highlighted. The results showed, high organic removal (95%), high methane conversion (90%) and low sludge yield (0.08gVSS/gCOD) were achieved in the AnMBR. Toilet-paper cellulose was fully biodegraded without accumulation in the mixed liquor and membrane cake layer. Bioconversion efficiency of toilet paper approached 100% under a high organic loading rate (OLR) of 2.02gCOD/L/d and it could provide around 26% of total methane generation at most of OLRs. Long sludge retention time and co-digestion of insoluble/soluble COD fractions achieving mutualism of functional microorganisms, contributed to biodegradation of toilet-paper cellulose. Therefore the AnMBR successfully implemented simultaneously methanogenic bioconversion of toilet-paper cellulose and soluble COD in sewage at room temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Simultaneous Detection and Removal of Formaldehyde at Room Temperature: Janus Au@ZnO@ZIF-8 Nanoparticles

    Science.gov (United States)

    Wang, Dawei; Li, Zhiwei; Zhou, Jian; Fang, Hong; He, Xiang; Jena, Puru; Zeng, Jing-Bin; Wang, Wei-Ning

    2018-03-01

    The detection and removal of volatile organic compounds (VOCs) are of great importance to reduce the risk of indoor air quality concerns. This study reports the rational synthesis of a dual-functional Janus nanostructure and its feasibility for simultaneous detection and removal of VOCs. The Janus nanostructure was synthesized via an anisotropic growth method, composed of plasmonic nanoparticles, semiconductors, and metal organic frameworks (e.g., Au@ZnO@ZIF-8). It exhibits excellent selective detection to formaldehyde (HCHO, as a representative VOC) at room temperature over a wide range of concentrations (from 0.25 to 100 ppm), even in the presence of water and toluene molecules as interferences. In addition, HCHO was also found to be partially oxidized into non-toxic formic acid simultaneously with detection. The mechanism underlying this technology was unraveled by both experimental measurements and theoretical calculations: ZnO maintains the conductivity, while ZIF-8 improves the selective gas adsorption; the plasmonic effect of Au nanorods enhances the visible-light-driven photocatalysis of ZnO at room temperature. [Figure not available: see fulltext.

  17. Stability of 2-Alkylcyclobutanones in irradiated retort pouch Gyudon topping during room temperature storage

    International Nuclear Information System (INIS)

    Kitagawa, Yoko; Okihashi, Masahiro; Takatori, Satoshi; Fukui, Naoki; Kajimura, Keiji; Obana, Hirotaka; Furuta, Masakazu

    2014-01-01

    2-Alkylcyclobutanones (ACBs), such as 2-dodecylcyclobutanone (DCB) and 2-tetradecylcylobutanone (TCB) are specific products from irradiated lipid. Thus, DCB and TCB are suitable for indicators of the irradiation history of food. The purpose of this study was to clarify the stability of ACBs in food, kept at room temperature for a long period. We evaluated DCB and TCB in irradiated retort pouch Gyudon topping (instant Gyudon mixes which were made from a beef, onion and soy sauce), which could be preserved for a long term at room temperature, after storage for one year. DCB and TCB were detected at doses of 0.6-4.5 kGy in irradiated retort pouch Gyudon topping. The peaks of DCB and TCB were separated from other peaks on the chromatogram with GC-MS. The concentration of DCB and TCB were periodically determined till 12 months later of irradiation. The dose-response curves of DCB and TCB were almost identical with those obtained from the samples after the 12 months storage at room temperature. These results concluded that DCB and TCB formed in retort pouch would stable at room temperature at least 12 months. (author)

  18. Transient optical studies of charge recombination dynamics in a polymer/fullerene composite at room temperature

    NARCIS (Netherlands)

    Montanari, Ivan; Nogueira, Ana F.; Nelson, Jenny; Durrant, James R.; Winder, Christoph; Loi, Maria Antonietta; Sariciftci, Niyazi Serdar; Brabec, Christoph

    2002-01-01

    The recombination kinetics of photogenerated charge carriers in a composite of poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1-4-phenylene vinylene], (MDMO–PPV) and the functionalised fullerene 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 are investigated at room temperature by transient absorption

  19. Structure determination of an integral membrane protein at room temperature from crystals in situ

    International Nuclear Information System (INIS)

    Axford, Danny; Foadi, James; Hu, Nien-Jen; Choudhury, Hassanul Ghani; Iwata, So; Beis, Konstantinos; Evans, Gwyndaf; Alguel, Yilmaz

    2015-01-01

    The X-ray structure determination of an integral membrane protein using synchrotron diffraction data measured in situ at room temperature is demonstrated. The structure determination of an integral membrane protein using synchrotron X-ray diffraction data collected at room temperature directly in vapour-diffusion crystallization plates (in situ) is demonstrated. Exposing the crystals in situ eliminates manual sample handling and, since it is performed at room temperature, removes the complication of cryoprotection and potential structural anomalies induced by sample cryocooling. Essential to the method is the ability to limit radiation damage by recording a small amount of data per sample from many samples and subsequently assembling the resulting data sets using specialized software. The validity of this procedure is established by the structure determination of Haemophilus influenza TehA at 2.3 Å resolution. The method presented offers an effective protocol for the fast and efficient determination of membrane-protein structures at room temperature using third-generation synchrotron beamlines

  20. Construction of hydrophobic wood surfaces by room temperature deposition of rutile (TiO2) nanostructures

    Science.gov (United States)

    Rongbo Zheng; Mandla A. Tshabalala; Qingyu Li; Hongyan Wang

    2015-01-01

    A convenient room temperature approach was developed for growing rutile TiO2 hierarchical structures on the wood surface by direct hydrolysis and crystallization of TiCl3 in saturated NaCl aqueous solution.The morphology and the crystal structure of TiO2 coated on the wood surface were characterized...

  1. Selective electrochemical extraction of REEs from NdFeB magnet waste at room temperature

    NARCIS (Netherlands)

    Venkatesan, P.; Vander Hoogerstraete, Tom; Hennebel, Tom; Binnemans, Koen; Sietsma, J.; Yang, Y.

    2018-01-01

    NdFeB magnet waste is one of the important secondary resources from which rare-earth elements (REEs) can be recovered. Herein we present an electrochemical route to selectively extract REEs from the magnet waste at room temperature. First, the magnet waste was partially leached with HCl. The

  2. Red-light-emitting laser diodes operating CW at room temperature

    Science.gov (United States)

    Kressel, H.; Hawrylo, F. Z.

    1976-01-01

    Heterojunction laser diodes of AlGaAs have been prepared with threshold current densities substantially below those previously achieved at room temperature in the 7200-8000-A spectral range. These devices operate continuously with simple oxide-isolated stripe contacts to 7400 A, which extends CW operation into the visible (red) portion of the spectrum.

  3. Red-light-emitting laser diodes operating cw at room temperature

    International Nuclear Information System (INIS)

    Kressel, H.; Hawrylo, F.Z.

    1976-01-01

    Heterojunction laser diodes of AlGaAs have been prepared with threshold current densities substantially below those previously achieved at room temperature in the 7200 to 8000-A spectral range. These devices operate cw with simple oxide-isolated stripe contacts to 7400 A, which extends cw operation for the first time into the visible (red) portion of the spectrum

  4. Room-temperature near-field reflection spectroscopy of single quantum wells

    DEFF Research Database (Denmark)

    Langbein, Wolfgang Werner; Hvam, Jørn Marcher; Madsen, Steen

    1997-01-01

    . This technique suppresses efficiently the otherwise dominating far-field background and reduces topographic artifacts. We demonstrate its performance on a thin, strained near-surface CdS/ZnS single quantum well at room temperature. The optical structure of these topographically flat samples is due to Cd...

  5. Electrochemical applications of room temperature ionic liquids in nuclear fuel cycle

    International Nuclear Information System (INIS)

    Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2008-01-01

    Applications of room temperature ionic liquids (RTILs) have invaded all branches of science. They are also receiving an upsurge, in recent years, for possible applications in various stages of nuclear fuel cycle. Ionic liquids are compounds composed entirely of ions existing in liquid state and RTILs are ionic liquids molten at temperatures lower than 373 K. RTILs are generally made up of an organic cation and an inorganic or an organic anion. Room temperature ionic liquids have several fascinating properties, which are unique to a particular combination of cation and anion. The properties such as insignificant vapor pressure, amazing ability to dissolve organic and inorganic compounds, wide electrochemical window are the specific advantages when dealing with application of RTILs for reprocessing of spent nuclear fuel. The ionic liquids are regarded as designer or tailor-made solvents as their properties can be tuned for desired application by appropriate cation-anion combinations. An excellent review by Wilkes describes about the historical perspectives of room temperature ionic liquids, pioneers in that area, events and the products delivered till 2001. Furthermore, several comprehensive reviews have been made on room temperature ionic liquids by various authors

  6. A review on the electrochemical applications of room temperature ionic liquids in nuclear fuel cycle

    International Nuclear Information System (INIS)

    Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2009-01-01

    A mini review on the electrochemical applications of room temperature ionic liquids (RTIL) in nuclear fuel cycle is presented. It is shown that how the fascinating properties of RTIL can be tuned to deliver desirable application in aqueous and non-aqueous reprocessing and in nuclear waste management. (author)

  7. Application of room temperature ionic liquids in advanced fuel cycles RIAR research concept program users

    International Nuclear Information System (INIS)

    Bychkov, Alexander V.; Kormilitsyn, Michael V.; Savochkin, Yuri P.; Osipenko, Alexander G.; Smolensky, Valeri V.; Shadrin, Alexander Yu.; Babain, Vladimir A.

    2005-01-01

    The paper reviews briefly the research program on application of Room Temperature Ionic Liquids (RTILs) in some processes of the nuclear fuel reprocessing, particularly in the uranium-aluminum fuel reprocessing and separation of TPEs and REEs from the PUREX process liquid waste, and approaches to implementation of this program. (author)

  8. Heat Capacity of Room-Temperature Ionic Liquids: A Critical Review

    Science.gov (United States)

    Paulechka, Yauheni U.

    2010-09-01

    Experimental data on heat capacity of room-temperature ionic liquids in the liquid state were compiled and critically evaluated. The compilation contains data for 102 aprotic ionic liquids from 63 literature references and covers the period of time from 1998 through the end of February 2010. Parameters of correlating equations for temperature dependence of the heat capacities were developed.

  9. Spin Squeezing and Entanglement with Room Temperature Atoms for Quantum Sensing and Communication

    DEFF Research Database (Denmark)

    Shen, Heng

    magnetometer at room temperature is reported. Furthermore, using spin-squeezing of atomic ensemble, the sensitivity of magnetometer is improved. Deterministic continuous variable teleportation between two distant atomic ensembles is demonstrated. The fidelity of teleportating dynamically changing sequence...... of spin states surpasses a classical benchmark, demonstrating the true quantum teleportation....

  10. Enhanced field emission of ZnO nanoneedle arrays via solution etching at room temperature

    DEFF Research Database (Denmark)

    Ma, Huanming; Qin, Zhiwei; Wang, Zaide

    2017-01-01

    ZnO nanoneedle arrays (ZnO nns) were synthesized by a facile two-step solution-phase method based on the etching of pre-synthesized ZnO nanowire arrays (ZnO nws) with flat ends at room temperature. Field emission measurement results showed that the turn-on electronic fields of ZnO nns and nws wer...

  11. Spin-on nanostructured silicon-silica film displaying room-temperature nanosecond lifetime photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Y.; Hatton, B.; Miguez, H.; Coombs, N.; Fournier-Bidoz, S.; Ozin, G.A. [Materials Chemistry Research Group, Department of Chemistry, Lash Miller Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 (Canada); Grey, J.K.; Beaulac, R.; Reber, C. [Department of Chemistry, University of Montreal, Montreal, Quebec H3C 3J7 (Canada)

    2003-04-17

    A yellow transparent mesoporous silica film has been achieved by the incorporation of silicon nanoclusters into its channels. The resulting nanocomposite - fabricated using a combination of evaporation induced self- assembly and chemical vapor deposition - emits light brightly at visible wavelengths and has nanosecond radiative lifetimes at room temperature when excited by ultraviolet light (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  12. Room temperature strong coupling effects from single ZnO nanowire microcavity

    KAUST Repository

    Das, Ayan; Heo, Junseok; Bayraktaroglu, Adrian; Guo, Wei; Ng, Tien Khee; Phillips, Jamie; Ooi, Boon S.; Bhattacharya, Pallab

    2012-01-01

    Strong coupling effects in a dielectric microcavity with a single ZnO nanowire embedded in it have been investigated at room temperature. A large Rabi splitting of ?100 meV is obtained from the polariton dispersion and a non

  13. Comparison of room temperature and cyrogenic sample processing in the analysis of chemical contaminants in foods

    Science.gov (United States)

    In this study, analytical results were compared when using different approaches to bulk food sample comminution, consisting of a vertical chopper (Blixer) at room temperature and at dry ice cryogenic conditions, followed by further subsample processing (20 g) using liquid nitrogen cryogenic conditio...

  14. Effect of irradiation on fresh-keeping of strawberry stored at room temperature

    International Nuclear Information System (INIS)

    Zhao Yongfu; Xie Zongchuan; Lu Zhaoxin

    1999-01-01

    The fresh keeping period of strawberry irradiated with 4.0 kGy dose and stored at room temperature was prolonged to 6 days. Further experiment showed that the irradiation treatment decreased the number of mold in strawberry by two orders of magnitude, inhibited the strawberry fruit respiration and water loss, therefore, improved the effect of strawberry fresh-keeping

  15. A method for electrochemical growth of homogeneous nanocrystalline ZnO thin films at room temperature

    Czech Academy of Sciences Publication Activity Database

    Pauporté, T.; Jirka, Ivan

    2009-01-01

    Roč. 54, č. 28 (2009), s. 7558-7564 ISSN 0013-4686 R&D Projects: GA AV ČR IAA400400909 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrodeposition * ZnO * room temperature * photoluminiscence Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.325, year: 2009

  16. CdO necklace like nanobeads decorated with PbS nanoparticles: Room temperature LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Sonawane, N.B. [Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon, 425001 M.S. (India); K.A.M.P. & N.K.P. Science College, Pimpalner, Sakri, Dhule, M.S. (India); Baviskar, P.K. [Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon, 425001 M.S. (India); Ahire, R.R. [S.G. Patil Science, Sakri, Dhule, M.S. (India); Sankapal, B.R., E-mail: brsankapal@gmail.com [Nano Materials and Device Laboratory, Department of Applied Physics, Visvesvaraya National Institute of Technology, South Ambazari Road, Nagpur, 440010 M.S. (India)

    2017-04-15

    Simple chemical route has been employed to grow interconnected nanobeads of CdO having necklace like structure through air annealing of cadmium hydroxide nanowires. This nanobeads of n-CdO with high surface area has been decorated with p-PbS nanoparticles resulting in the formation of nano-heterojunction which has been utilized effectively as room temperature liquefied petroleum gas (LPG) sensor. The room temperature gas response towards C{sub 2}H{sub 5}OH, Cl{sub 2}, NH{sub 3}, CO{sub 2} and LPG was investigated, among which LPG exhibits significant response. The maximum gas response of 51.10% is achieved with 94.54% stability upon exposure of 1176 ppm concentration of LPG at room temperature (27 °C). The resulting parameters like gas response, response and recovery time along with stability studies has been studied and results are discussed herein. - Highlights: • Conversion of Cd(OH){sub 2} nanowires to CdO nanonecklace by air annealing at 290 °C. • Decoration of PbS nanoparticles over CdO nanobeads by SILAR method. • Formation of n-CdO/p-PbS nano-heterojunction as room temperature LPG sensor. • Maximum gas response of 51.10% with 94.54% stability.

  17. Non-local electrical spin injection and detection in germanium at room temperature

    Science.gov (United States)

    Rortais, F.; Vergnaud, C.; Marty, A.; Vila, L.; Attané, J.-P.; Widiez, J.; Zucchetti, C.; Bottegoni, F.; Jaffrès, H.; George, J.-M.; Jamet, M.

    2017-10-01

    Non-local carrier injection/detection schemes lie at the very foundation of information manipulation in integrated systems. This paradigm consists in controlling with an external signal the channel where charge carriers flow between a "source" and a well separated "drain." The next generation electronics may operate on the spin of carriers in addition to their charge and germanium appears as the best hosting material to develop such a platform for its compatibility with mainstream silicon technology and the predicted long electron spin lifetime at room temperature. In this letter, we demonstrate injection of pure spin currents (i.e., with no associated transport of electric charges) in germanium, combined with non-local spin detection at 10 K and room temperature. For this purpose, we used a lateral spin valve with epitaxially grown magnetic tunnel junctions as spin injector and spin detector. The non-local magnetoresistance signal is clearly visible and reaches ≈15 mΩ at room temperature. The electron spin lifetime and diffusion length are 500 ps and 1 μm, respectively, the spin injection efficiency being as high as 27%. This result paves the way for the realization of full germanium spintronic devices at room temperature.

  18. Achieving Room Temperature Orange Lasing Using InGaP/InAlGaP Diode Laser

    KAUST Repository

    Al-Jabr, Ahmad

    2015-09-28

    We demonstrated the first orange laser diode at room temperature with a decent total output power of ∼46mW and lasing wavelength of 608nm, using a novel strain-induced quantum well intermixing in InGaP/InAlGaP red laser structure.

  19. Structure determination of an integral membrane protein at room temperature from crystals in situ

    Energy Technology Data Exchange (ETDEWEB)

    Axford, Danny [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Foadi, James [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Hu, Nien-Jen; Choudhury, Hassanul Ghani [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Iwata, So [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Kyoto University, Kyoto 606-8501 (Japan); Beis, Konstantinos [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Evans, Gwyndaf, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Alguel, Yilmaz, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom)

    2015-05-14

    The X-ray structure determination of an integral membrane protein using synchrotron diffraction data measured in situ at room temperature is demonstrated. The structure determination of an integral membrane protein using synchrotron X-ray diffraction data collected at room temperature directly in vapour-diffusion crystallization plates (in situ) is demonstrated. Exposing the crystals in situ eliminates manual sample handling and, since it is performed at room temperature, removes the complication of cryoprotection and potential structural anomalies induced by sample cryocooling. Essential to the method is the ability to limit radiation damage by recording a small amount of data per sample from many samples and subsequently assembling the resulting data sets using specialized software. The validity of this procedure is established by the structure determination of Haemophilus influenza TehA at 2.3 Å resolution. The method presented offers an effective protocol for the fast and efficient determination of membrane-protein structures at room temperature using third-generation synchrotron beamlines.

  20. The physics and chemistry of room-temperature liquid-filled ionization chambers

    International Nuclear Information System (INIS)

    Holroyd, R.A.

    1985-01-01

    The properties of excess electrons in non-polar liquids, such as tetramethylsilane and 2,2,4,4-tetramethylpentane, which are suitable for room-temperature liquid-filled ionization chambers are reviewed. Such properties as mobility, ionization yield, conduction band energy, trapping, and the influence of the electric field are considered. (orig.)

  1. Room-temperature 1.2-J Fe{sup 2+}:ZnSe laser

    Energy Technology Data Exchange (ETDEWEB)

    Velikanov, S D; Zaretsky, N A; Zotov, E A; Maneshkin, A A; Yutkin, I M [Russian Federal Nuclear Center ' All-Russian Research Institute of Experimental Physics' , Sarov, Nizhnii Novgorod region (Russian Federation); Kazantsev, S Yu; Kononov, I G; Firsov, K N [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Korostelin, Yu V; Frolov, M P [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2016-01-31

    The characteristics of a laser based on a Fe{sup 2+}:ZnSe single crystal pumped by an electric-discharge HF laser at room temperature are studied. The HF laser beam diameter on the crystal surface was 17 mm. The achieved laser energy was 1.2 J with an efficiency of ∼ 25% with respect to the pump energy. (letters)

  2. Room temperature synthesis of protonated layered titanate sheets using peroxo titanium carbonate complex solution.

    Science.gov (United States)

    Sutradhar, Narottam; Sinhamahapatra, Apurba; Pahari, Sandip Kumar; Bajaj, Hari C; Panda, Asit Baran

    2011-07-21

    We report the synthesis of peroxo titanium carbonate complex solution as a novel water-soluble precursor for the direct synthesis of layered protonated titanate at room temperature. The synthesized titanates showed excellent removal capacity for Pb(2+) and methylene blue. Based on experimental observations, a probable mechanism for the formation of protonated layered dititanate sheets is also discussed.

  3. Studies on room temperature electrochemical oxidation and its effect on the transport properties of TBCCO films

    International Nuclear Information System (INIS)

    Shirage, P M; Shivagan, D D; Pawar, S H

    2004-01-01

    A novel room temperature electrochemical process for the synthesis of single-phase Tl 2 Ba 2 Ca 2 Cu 3 O 10 (TBCCO/Tl-2223) superconducting films has been developed. Electrochemical parameters were optimized by studying linear sweep voltammetry (LSV), cyclic voltammetry (CV) and chronoamperometry (CA) for the deposition of Tl-Ba-Ca-Cu alloy at room temperature. The superconducting films of the TBCCO were obtained by two oxidation techniques. In the first technique, the electrodeposited Tl-Ba-Ca-Cu alloyed films were oxidized at various temperatures in flowing oxygen atmosphere. In the second technique, stoichiometric electrocrystallization to get Tl 2 Ba 2 Ca 2 Cu 3 O 10 (Tl-2223) was completed by electrochemically intercalating oxygen species into Tl-Ba-Ca-Cu alloy at room temperature for various lengths of time. The oxygen content in the samples was varied by varying the electrochemical oxidation period, and the changes in the crystal structure, superconducting transition temperature (T c ) and critical current density (J c ) were recorded. The high temperature furnace oxidation technique was replaced by the room temperature electrochemical oxidation technique. The dependence of superconducting parameters on oxygen content is correlated with structure-property relations

  4. Room temperature vortex fluidic synthesis of monodispersed amorphous proto-vaterite.

    Science.gov (United States)

    Peng, Wenhong; Chen, Xianjue; Zhu, Shenmin; Guo, Cuiping; Raston, Colin L

    2014-10-11

    Monodispersed particles of amorphous calcium carbonate (ACC) 90 to 200 nm in diameter are accessible at room temperature in ethylene glycol and water using a vortex fluidic device (VFD). The ACC material is stable for at least two weeks under ambient conditions.

  5. Aqueous synthesis of porous platinum nanotubes at room temperature and their intrinsic peroxidase-like activity.

    Science.gov (United States)

    Cai, Kai; Lv, Zhicheng; Chen, Kun; Huang, Liang; Wang, Jing; Shao, Feng; Wang, Yanjun; Han, Heyou

    2013-07-11

    Platinum nanotubes (PtNTs) exhibiting high porosity were constructed by sacrificing the exterior of tellurium nanowires (TeNWs) and disintegrating the inner part spontaneously in aqueous solution at room temperature, in which the Kirkendall effect may play an important role. The present PtNTs exhibited intrinsic peroxidase-like activity in the presence of H2O2.

  6. Room temperature aerobic oxidation of amines by a nanocrystalline ruthenium oxide pyrochlore nafion composite catalyst.

    Science.gov (United States)

    Venkatesan, Shanmuganathan; Kumar, Annamalai Senthil; Lee, Jyh-Fu; Chan, Ting-Shan; Zen, Jyh-Myng

    2012-05-14

    The aerobic oxidation of primary amines to their respective nitriles has been carried out at room temperature using a highly reusable nanocrystalline ruthenium oxide pyrochlore Nafion composite catalyst (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The synthesis of [2-13C]2-nitropropane at room temperature and at atmospheric pressure

    NARCIS (Netherlands)

    Jacquemijns M; Zomer G

    1990-01-01

    In this report the synthesis of [2-13C]2-nitropropane at room temperature is described. [2-13C]Acetone was converted into the oxime with hydroxy hydrochloridelamine and sodium carbonate. Treatment with hypobromic acid resulted in 2-13C]2-bromo-2-nitropropane. Hydrogenation with sodium borohydride

  8. Highly selective room temperature NO2 gas sensor based on rGO-ZnO composite

    Science.gov (United States)

    Jyoti, Kanaujiya, Neha; Varma, G. D.

    2018-05-01

    Blending metal oxide nanoparticles with graphene or its derivatives can greatly enhance gas sensing characteristics. In the present work, ZnO nanoparticles have been synthesized via reflux method. Thin films of reduced graphene oxide (rGO) and composite of rGO-ZnO have been fabricated by drop casting method for gas sensing application. The samples have been characterized by X-ray diffraction (XRD) and Field-emission scanning electron microscope (FESEM) for the structural and morphological studies respectively. Sensing measurements have been carried out for the composite film of rGO-ZnO for different concentrations of NO2 ranging from 4 to 100 ppm. Effect of increasing temperature on the sensing performance has also been studied and the rGO-ZnO composite sensor shows maximum percentage response at room temperature. The limit of detection (LOD) for rGO-ZnO composite sensor is 4ppm and it exhibits a high response of 48.4% for 40 ppm NO2 at room temperature. To check the selectivity of the composite sensor, sensor film has been exposed to 40 ppm different gases like CO, NH3, H2S and Cl2 at room temperature and the sensor respond negligibly to these gases. The present work suggests that rGO-ZnO composite material can be a better candidate for fabrication of highly selective room temperature NO2 gas sensor.

  9. Room temperature Compton profiles of conduction electrons in α-Ga ...

    Indian Academy of Sciences (India)

    B P PANDA and N C MOHAPATRA*. Department of Physics, Chikiti Mahavidyalaya, Chikiti 761 010, India. £Department of Physics, Berhampur University, Berhampur 760 007, India. Email: ncmphy123@hotmail.com. MS received 18 January 2003; accepted 21 June 2003. Abstract. Room temperature Compton profiles of ...

  10. GREEN SYNTHESIS OF SILVER AND PALLADIUM NANOPARTICLES AT ROOM TEMPERATURE USING COFFEE AND TEA EXTRACT

    Science.gov (United States)

    An extremely simple green approach that generates bulk quantities of nanocrystals of noble metals such as silver (Ag) and palladium (Pd) using coffee and tea extract at room temperature is described. The single-pot method uses no surfactant, capping agent, and/or template. The ob...

  11. Instantaneous radioiodination of rose bengal at room temperature and a cold-kit therefor. [DOE patent application

    Science.gov (United States)

    O'Brien, H. Jr.; Hupf, H.B.; Wanek, P.M.

    The disclosure relates to the radioiodination of rose bengal at room temperature and a cold-kit therefor. A purified rose bengal tablet is stirred into acidified ethanol at or near room temperature, until a suspension forms. Reductant-free /sup 125/I/sup -/ is added and the resulting mixture stands until the exchange label reaction occurs at room temperature. A solution of sterile isotonic phosphate buffer and sodium hydroxide is added and the final resulting mixture is sterilized by filtration.

  12. Vitamin D analogue therapy, cardiovascular risk and kidney function in people with Type 1 diabetes mellitus and diabetic nephropathy

    DEFF Research Database (Denmark)

    Joergensen, C; Tarnow, L; Goetze, J P

    2015-01-01

    AIM: To evaluate the effects of therapy with the vitamin D analogue paricalcitol on markers of cardiovascular risk and kidney function in people with Type 1 diabetes mellitus and diabetic nephropathy. METHODS: In a double-blind, randomized placebo-controlled, crossover trial, 48 participants on s...

  13. Function-oriented synthesis: biological evaluation of laulimalide analogues derived from a last step cross metathesis diversification strategy.

    Science.gov (United States)

    Mooberry, Susan L; Hilinski, Michael K; Clark, Erin A; Wender, Paul A

    2008-01-01

    Laulimalide is a potent microtubule stabilizing agent and a promising anticancer therapeutic lead. The identification of stable, efficacious and accessible analogues is critical to clinically exploiting this novel lead. To determine which structural features of laulimalide are required for beneficial function and thus for accessing superior clinical candidates, a series of side chain analogues were prepared through a last step cross metathesis diversification strategy and their biological activities were evaluated. Five analogues, differing in potency from 233 nM to 7.9 muM, effectively inhibit cancer cell proliferation. Like laulimalide, they retain activity against multidrug resistant cells, stabilize microtubules and cause the formation of aberrant mitotic spindles, mitotic accumulation, Bcl-2 phosphorylation and initiation of apoptosis. Structural modifications in the C 23-C 27 dihydropyran side chain can be made without changing the overall mechanism of action, but it is clear that this subunit has more than a bystander role.

  14. Direct writing of flexible electronics through room temperature liquid metal ink.

    Directory of Open Access Journals (Sweden)

    Yunxia Gao

    Full Text Available BACKGROUND: Conventional approaches of making a flexible circuit are generally complex, environment unfriendly, time and energy consuming, and thus expensive. Here, we describe for the first time the method of using high-performance GaIn(10-based electrical ink, a significantly neglected room temperature liquid metal, as both electrical conductors and interconnects, for directly writing flexible electronics via a rather easy going and cost effective way. METHODS: The new generation electric ink was made and its wettability with various materials was modified to be easily written on a group of either soft or rigid substrates such as epoxy resin board, glass, plastic, silica gel, paper, cotton, textiles, cloth and fiber etc. Conceptual experiments were performed to demonstrate and evaluate the capability of directly writing the electrical circuits via the invented metal ink. Mechanisms involved were interpreted through a series of fundamental measurements. RESULTS: The electrical resistivity of the fluid like GaIn(10-based material was measured as 34.5 µΩ·cm at 297 K by four point probe method and increased with addition of the oxygen quantity, which indicates it as an excellent metal ink. The conductive line can be written with features that are approximately 10 µm thick. Several functional devices such as a light emitting diode (LED array showing designed lighting patterns and electrical fan were made to work by directly writing the liquid metal on the specific flexible substrates. And satisfactory performances were obtained. CONCLUSIONS: The present method opens the way to directly and quickly writing flexible electronics which can be as simple as signing a name or drawing a picture on the paper. The unique merit of the GaIn(10-based liquid metal ink lies in its low melting temperature, well controlled wettability, high electrical conductivity and good biocompability. The new electronics writing strategy and basic principle has generalized

  15. Combined techniques for studying actinide complexes in room temperature ionic liquids

    International Nuclear Information System (INIS)

    Gaillard, C.; Billard, I.; Mekki, S.; Ouadi, A.; Hennig, Ch.; Denecke, M.A.

    2007-01-01

    Room temperature ionic liquids (RTILs) are a new class of solvents. Their main interest is related to their 'green' properties (non-volatile, non-flammable, etc.), but also from the variability of their physico-chemical properties (stability, hydrophobicity, viscosity) as a function of the RTIL cationic and anionic components. In the frame of the nuclear fuel reprocessing, RTILs are particularly attractive in order to improve existing processes or to develop new ones for actinide and lanthanide partitioning, in replacement of toxic solvents used nowadays, for metal electrodeposition or for liquid/liquid extraction by the use of task specific ionic liquids. However, despite the increasing number of publications devoted to ionic liquids, the solvation effects, the solute-solvent and solvent-solvent interactions are still hardly known. These fundamental aspects are of tremendous importance to the understanding of the solvating properties of these new solvents. In this frame, we have undertaken studies on the solvation and complexation of lanthanides (III) and actinides in RTILs, by the use of spectroscopic techniques. Experiments were led in various ionic liquids in order to highlight the role of the anionic part of the RTILs on the reactivity of the studied cations. Results have clearly shown that solvation phenomena in RTILs are not as 'simple' as in classical solvents. The dissolution of a Ln/An salt, even if complete, does not imply dissociation and solvation of the metal cation by the RTILs anions only. The nature of first co-ordination sphere of Ln/An depends on the competition between its counter-anions and the RTIL anions, which, in turn, influence the complexation reaction with other added anions such as chlorides. (authors)

  16. Dielectric response and room temperature ferromagnetism in Cr doped anatase TiO2 nanoparticles

    Science.gov (United States)

    Naseem, Swaleha; Khan, Wasi; Khan, Shakeel; Husain, Shahid; Ahmad, Abid

    2018-02-01

    In the present work, nanocrystalline samples of Ti1-xCrxO2 (x = 0, 0.02, 0.04, 0.06 and 0.08) were synthesized in anatase phase through simple and cost effective acid modified sol gel method. The influence of Cr doping on thermal, microstructural, electrical and magnetic properties was investigated in TiO2 host matrix. The surface morphology has revealed less agglomeration and considerable reduction in particle size in case of Cr doped TiO2 as compared to undoped TiO2 nanoparticles (NPs). Energy dispersive x-ray spectroscopy (EDS), Raman and X-ray photoelectron spectroscopy (XPS) established high purity, appropriate stoichiometry and oxidation states of the compositions. The dielectric properties of the nanoparticles were altered by the doping concentration, applied frequency as well as temperature variation. The variation in dielectric constant (ε‧), dielectric loss (δ) and ac conductivity as a function of frequency and temperature at different doping concentration of Cr were interpreted in the light of Maxwell Wagner theory, space charge polarization mechanism and drift mobility of charge carriers. Both undoped and Cr doped TiO2 samples exhibit room temperature ferromagnetism (RTFM) that remarkably influenced by means of the Cr content. The significant enhancement in the magnetization was observed at 4% Cr doping. However, decrease in magnetization for higher doping signify antiferromagnetic interactions between Cr ions or superexchange mechanism. These results reveal that the oxygen vacancies play a crucial role to initiate the RTFM. Therefore, the present investigation suggests the potential applications of Cr doped TiO2 nanoparticles for spintronics application.

  17. Direct writing of flexible electronics through room temperature liquid metal ink.

    Science.gov (United States)

    Gao, Yunxia; Li, Haiyan; Liu, Jing

    2012-01-01

    Conventional approaches of making a flexible circuit are generally complex, environment unfriendly, time and energy consuming, and thus expensive. Here, we describe for the first time the method of using high-performance GaIn(10)-based electrical ink, a significantly neglected room temperature liquid metal, as both electrical conductors and interconnects, for directly writing flexible electronics via a rather easy going and cost effective way. The new generation electric ink was made and its wettability with various materials was modified to be easily written on a group of either soft or rigid substrates such as epoxy resin board, glass, plastic, silica gel, paper, cotton, textiles, cloth and fiber etc. Conceptual experiments were performed to demonstrate and evaluate the capability of directly writing the electrical circuits via the invented metal ink. Mechanisms involved were interpreted through a series of fundamental measurements. The electrical resistivity of the fluid like GaIn(10)-based material was measured as 34.5 µΩ·cm at 297 K by four point probe method and increased with addition of the oxygen quantity, which indicates it as an excellent metal ink. The conductive line can be written with features that are approximately 10 µm thick. Several functional devices such as a light emitting diode (LED) array showing designed lighting patterns and electrical fan were made to work by directly writing the liquid metal on the specific flexible substrates. And satisfactory performances were obtained. The present method opens the way to directly and quickly writing flexible electronics which can be as simple as signing a name or drawing a picture on the paper. The unique merit of the GaIn(10)-based liquid metal ink lies in its low melting temperature, well controlled wettability, high electrical conductivity and good biocompability. The new electronics writing strategy and basic principle has generalized purpose and can be extended to more industrial areas, even

  18. Abnormal room temperature ferromagnetism in CuO/ZnO nanocomposites via hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ping; Zhou, Wei; Li, Ying; Wang, Jianchun; Wu, Ping, E-mail: pingwu@tju.edu.cn

    2017-03-31

    Highlights: • CuO/ZnO nanocomposites have been synthesized by a one-step hydrothermal method. • The interaction between ZnO and CuO causes a modification of electronic structure. • The abnormal RTFM is discovered at the interface of CuO/ZnO. • The M{sub S} can be tuned by changing the phase ratios of the CuO and ZnO. • The indirect double-exchange model was employed to explain the origin of magnetism. - Abstract: CuO/ZnO nanocomposites have been successfully synthesized by a one-step hydrothermal method with different phase ratios. Field emission scanning electron microscopy and transmission electron microscopy results show that the obtained products of nanosheets are composed of small primary particles with an average size of about 20 nm. With the increasing proportion of CuO phase, nanosheets have significant collapse and the amount of small sheets increases obviously. The abnormal room temperature ferromagnetism was discovered at the interface between diamagnetic ZnO and antiferromagnetic CuO, which can be tuned by changing the phase ratios. Optical spectra indicate that the interaction between ZnO and CuO modifies the electronic structure of nanocomposites. XPS results verify the valence change of Cu ions and the presence of oxygen vacancies, which are ultimately responsible for the observed ferromagnetism. The indirect double-exchange model was employed to explain the origin of magnetism. Our study suggests that magnetically functional interfaces exhibit very appealing properties for novel devices.

  19. The PedsQL™ Present Functioning Visual Analogue Scales: preliminary reliability and validity

    Directory of Open Access Journals (Sweden)

    Varni James W

    2006-10-01

    Full Text Available Abstract Background The PedsQL™ Present Functioning Visual Analogue Scales (PedsQL™ VAS were designed as an ecological momentary assessment (EMA instrument to rapidly measure present or at-the-moment functioning in children and adolescents. The PedsQL™ VAS assess child self-report and parent-proxy report of anxiety, sadness, anger, worry, fatigue, and pain utilizing six developmentally appropriate visual analogue scales based on the well-established Varni/Thompson Pediatric Pain Questionnaire (PPQ Pain Intensity VAS format. Methods The six-item PedsQL™ VAS was administered to 70 pediatric patients ages 5–17 and their parents upon admittance to the hospital environment (Time 1: T1 and again two hours later (Time 2: T2. It was hypothesized that the PedsQL™ VAS Emotional Distress Summary Score (anxiety, sadness, anger, worry and the fatigue VAS would demonstrate moderate to large effect size correlations with the PPQ Pain Intensity VAS, and that patient" parent concordance would increase over time. Results Test-retest reliability was demonstrated from T1 to T2 in the large effect size range. Internal consistency reliability was demonstrated for the PedsQL™ VAS Total Symptom Score (patient self-report: T1 alpha = .72, T2 alpha = .80; parent proxy-report: T1 alpha = .80, T2 alpha = .84 and Emotional Distress Summary Score (patient self-report: T1 alpha = .74, T2 alpha = .73; parent proxy-report: T1 alpha = .76, T2 alpha = .81. As hypothesized, the Emotional Distress Summary Score and Fatigue VAS were significantly correlated with the PPQ Pain VAS in the medium to large effect size range, and patient and parent concordance increased from T1 to T2. Conclusion The results demonstrate preliminary test-retest and internal consistency reliability and construct validity of the PedsQL™ Present Functioning VAS instrument for both pediatric patient self-report and parent proxy-report. Further field testing is required to extend these initial

  20. Performance evaluation of ZnO–CuO hetero junction solid state room temperature ethanol sensor

    International Nuclear Information System (INIS)

    Yu, Ming-Ru; Suyambrakasam, Gobalakrishnan; Wu, Ren-Jang; Chavali, Murthy

    2012-01-01

    Graphical abstract: Sensor response (resistance) curves of time were changed from 150 ppm to 250 ppm alcohol concentration of ZnO–CuO 1:1. The response and recovery times were measured to be 62 and 83 s, respectively. The sensing material ZnO–CuO is a high potential alcohol sensor which provides a simple, rapid and highly sensitive alcohol gas sensor operating at room temperature. Highlights: ► The main advantages of the ethanol sensor are as followings. ► Novel materials ZnO–CuO ethanol sensor. ► The optimized ZnO–CuO hetero contact system. ► A good sensor response and room working temperature (save energy). -- Abstract: A semiconductor ethanol sensor was developed using ZnO–CuO and its performance was evaluated at room temperature. Hetero-junction sensor was made of ZnO–CuO nanoparticles for sensing alcohol at room temperature. Nanoparticles were prepared by hydrothermal method and optimized with different weight ratios. Sensor characteristics were linear for the concentration range of 150–250 ppm. Composite materials of ZnO–CuO were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR) and high-resolution transmission electron microscopy (HR-TEM). ZnO–CuO (1:1) material showed maximum sensor response (S = R air /R alcohol ) of 3.32 ± 0.1 toward 200 ppm of alcohol vapor at room temperature. The response and recovery times were measured to be 62 and 83 s, respectively. The linearity R 2 of the sensor response was 0.9026. The sensing materials ZnO–CuO (1:1) provide a simple, rapid and highly sensitive alcohol gas sensor operating at room temperature.

  1. Room-temperature nine-µm-wavelength photodetectors and GHz-frequency heterodyne receivers

    Science.gov (United States)

    Palaferri, Daniele; Todorov, Yanko; Bigioli, Azzurra; Mottaghizadeh, Alireza; Gacemi, Djamal; Calabrese, Allegra; Vasanelli, Angela; Li, Lianhe; Davies, A. Giles; Linfield, Edmund H.; Kapsalidis, Filippos; Beck, Mattias; Faist, Jérôme; Sirtori, Carlo

    2018-04-01

    Room-temperature operation is essential for any optoelectronics technology that aims to provide low-cost, compact systems for widespread applications. A recent technological advance in this direction is bolometric detection for thermal imaging, which has achieved relatively high sensitivity and video rates (about 60 hertz) at room temperature. However, owing to thermally induced dark current, room-temperature operation is still a great challenge for semiconductor photodetectors targeting the wavelength band between 8 and 12 micrometres, and all relevant applications, such as imaging, environmental remote sensing and laser-based free-space communication, have been realized at low temperatures. For these devices, high sensitivity and high speed have never been compatible with high-temperature operation. Here we show that a long-wavelength (nine micrometres) infrared quantum-well photodetector fabricated from a metamaterial made of sub-wavelength metallic resonators exhibits strongly enhanced performance with respect to the state of the art up to room temperature. This occurs because the photonic collection area of each resonator is much larger than its electrical area, thus substantially reducing the dark current of the device. Furthermore, we show that our photonic architecture overcomes intrinsic limitations of the material, such as the drop of the electronic drift velocity with temperature, which constrains conventional geometries at cryogenic operation. Finally, the reduced physical area of the device and its increased responsivity allow us to take advantage of the intrinsic high-frequency response of the quantum detector at room temperature. By mixing the frequencies of two quantum-cascade lasers on the detector, which acts as a heterodyne receiver, we have measured a high-frequency signal, above four gigahertz (GHz). Therefore, these wide-band uncooled detectors could benefit technologies such as high-speed (gigabits per second) multichannel coherent data

  2. A primary exploration to quasi-two-dimensional rare-earth ferromagnetic particles: holmium-doped MoS2 sheet as room-temperature magnetic semiconductor

    Science.gov (United States)

    Chen, Xi; Lin, Zheng-Zhe

    2018-05-01

    Recently, two-dimensional materials and nanoparticles with robust ferromagnetism are even of great interest to explore basic physics in nanoscale spintronics. More importantly, room-temperature magnetic semiconducting materials with high Curie temperature is essential for developing next-generation spintronic and quantum computing devices. Here, we develop a theoretical model on the basis of density functional theory calculations and the Ruderman-Kittel-Kasuya-Yoshida theory to predict the thermal stability of two-dimensional magnetic materials. Compared with other rare-earth (dysprosium (Dy) and erbium (Er)) and 3 d (copper (Cu)) impurities, holmium-doped (Ho-doped) single-layer 1H-MoS2 is proposed as promising semiconductor with robust magnetism. The calculations at the level of hybrid HSE06 functional predict a Curie temperature much higher than room temperature. Ho-doped MoS2 sheet possesses fully spin-polarized valence and conduction bands, which is a prerequisite for flexible spintronic applications.

  3. Rhodium(III)-Catalyzed Activation of C(sp3)-H Bonds and Subsequent Intermolecular Amidation at Room Temperature.

    Science.gov (United States)

    Huang, Xiaolei; Wang, Yan; Lan, Jingbo; You, Jingsong

    2015-08-03

    Disclosed herein is a Rh(III)-catalyzed chelation-assisted activation of unreactive C(sp3)-H bonds, thus enabling an intermolecular amidation to provide a practical and step-economic route to 2-(pyridin-2-yl)ethanamine derivatives. Substrates with other N-donor groups are also compatible with the amidation. This protocol proceeds at room temperature, has a relatively broad functional-group tolerance and high selectivity, and demonstrates the potential of rhodium(III) in the promotive functionalization of unreactive C(sp3)-H bonds. A rhodacycle having a SbF6(-) counterion was identified as a plausible intermediate. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Taioli, Simone [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Chemistry, University of Bologna, Bologna (Italy); Garberoglio, Giovanni [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Simonucci, Stefano [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Physics, University of Camerino, Camerino (Italy); Beccara, Silvio a [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Aversa, Lucrezia [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Nardi, Marco [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Berlin (Germany); Verucchi, Roberto [Institute of Materials for Electronics and Magnetism, FBK-CNR, Trento (Italy); Iannotta, Salvatore [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Parma (Italy); Dapor, Maurizio [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Materials Engineering and Industrial Technologies, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova (Italy); and others

    2013-01-28

    In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-of-equilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse the Si-C{sub 60} collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C{sub 60} impact on the Si surface is in good agreement with our experimental findings.

  5. Biomimetic Aerobic C–H Olefination of Cyclic Enaminones at Room Temperature: Development toward the Synthesis of 1,3,5-Trisubstituted Benzenes

    Science.gov (United States)

    Yu, Yi-Yun

    2014-01-01

    A green and mild protocol for the dehydrogenative olefination of cyclic enaminones was devised via palladium catalysis at room temperature using oxygen as the terminal oxidant. The synthetic utility of the olefinated cyclic enaminones afforded a series of unique 1,3,5-trisubstituted benzenes via an unanticipated Diels-Alder tandem reaction. The broad substrate scope and good yields achieved with this new protocol provide an alternative pathway for arene functionalization. PMID:25071423

  6. Biomimetic Aerobic C-H Olefination of Cyclic Enaminones at Room Temperature: Development toward the Synthesis of 1,3,5-Trisubstituted Benzenes.

    Science.gov (United States)

    Yu, Yi-Yun; Georg, Gunda I

    2014-04-14

    A green and mild protocol for the dehydrogenative olefination of cyclic enaminones was devised via palladium catalysis at room temperature using oxygen as the terminal oxidant. The synthetic utility of the olefinated cyclic enaminones afforded a series of unique 1,3,5-trisubstituted benzenes via an unanticipated Diels-Alder tandem reaction. The broad substrate scope and good yields achieved with this new protocol provide an alternative pathway for arene functionalization.

  7. Effects of progestagens and prostaglandin analogues on ovarian function and embryo viability in sheep.

    Science.gov (United States)

    Gonzalez-Bulnes, A; Veiga-Lopez, A; Garcia, P; Garcia-Garcia, R M; Ariznavarreta, C; Sanchez, M A; Tresguerres, J A F; Cocero, M J; Flores, J M

    2005-06-01

    Current study assessed differences in the response of sheep to estrus synchronization either by the administration of two doses of prostaglandin or by the insertion of an intravaginal progestagen sponge. The preovulatory follicular dynamics and estradiol secretion, the ovulatory response and progesterone secretion and the number and quality of embryos were studied in 27 ewes treated with two doses of 100 microg of cloprostenol, 10 days apart, and in 29 sheep treated with progestagen sponges for 14 days. Percentage of sheep responding to the synchronization treatments with signs of estrus behaviour was similar between both groups (81.5% versus 72.4%, respectively). The use of progestagen resulted in a higher diameter of the largest follicle (6.6+/-0.2 versus 5.9+/-0.2, Psheep (Pprogesterone concentration during the early luteal phase was again higher in sheep treated with cloprostenol (P<0.05). The mean number of retrieved oocytes/embryos was very similar in both treatments (1.2+/-0.2 versus 1.4+/-0.2) and showed similar fertilization rates (70.6% versus 66.7%), but, although differences did not reach statistical significance, final viability rate was higher in cloprostenol than in progestagen treated ewes (58.9% versus 46.1%, P=0.07). Current results give new evidences supporting the negative effects of progestagens on the functionality of ovulatory follicles and support the development of new protocols for assisted reproduction including the use of prostaglandin analogues.

  8. Changes in renal function after discontinuation of vitamin D analogues in advanced chronic kidney disease.

    Science.gov (United States)

    Caravaca, Francisco; Caravaca-Fontán, Fernando; Azevedo, Lilia; Luna, Enrique

    In routine clinical practice, the prescription of vitamin D analogues (VDA) in patients with chronic kidney disease (CKD) is often associated with a decline of the estimated renal function. The reason for this is not fully understood. To analyse the effects of VDA discontinuation in advanced CKD and to determine the factors associated with changes in renal function. Retrospective cohort study of adult patients with advanced CKD. The case subgroup was treated with VDA and this medication was discontinued at baseline (the first visit). The control subgroup was not treated with VDA and they were selected according to comparability principles for CKD progression by propensity score matching. The primary outcome measure was a change to both the estimated glomerular filtration rate (MDRD-GFR) and the measured glomerular filtration rate (mGFR by combined creatinine and urea clearances). Baseline parameters related to mineral metabolism and creatinine generation were analysed as potential determinants of renal function changes. The study sample consisted of 67 cases and 67 controls. Renal function improved in 67% of cases and worsened in 72% of controls (p<0.0001). Changes in MDRD-GFR for the case subgroup and the control subgroup were +0.455±0.997 vs. -0.436±1.103ml/min/1.73 m 2 /month (p<0.0001), respectively. Total creatinine excretion was slightly higher in cases than in controls but the difference was not significant. According to multivariate logistic and linear regression analyses, baseline total serum calcium was one of the best determinants of both renal function recovery (Odds ratio=3.49; p=0.001), and of the extent of renal function recovery (beta=0.276; p=0.001). Discontinuation of VDA treatment in CKD patients is associated with significant recovery of estimated renal function. The extent of these changes is mainly associated with baseline total serum calcium. Copyright © 2017 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All

  9. Room temperature thin foil SLIM-cut using an epoxy paste: experimental versus theoretical results

    International Nuclear Information System (INIS)

    Bellanger, Pierre; Serra, Joao; Bouchard, Pierre-Olivier; Bernacki, Marc

    2015-01-01

    The stress induced lift-off method (SLIM) -cut technique allows the detachment of thin silicon foils using a stress inducing layer. In this work, results of SLIM-cut foils obtained using an epoxy stress inducing layer at room temperature are presented. Numerical analyses were performed in order to study and ascertain the important experimental parameters. The experimental and simulation results are in good agreement. Indeed, large area (5 × 5 cm 2 ) foils were successfully detached at room temperature using an epoxy thickness of 900 μm and a curing temperature of 150 °C. Moreover, three foils (5 × 3 cm 2 ) with thickness 135, 121 and 110 μm were detached from the same monocrystalline substrate. Effective minority carrier lifetimes of 46, 25 and 20 μs were measured using quasi-steady-state photoconductance technique in these foils after iodine ethanol surface passivation. (paper)

  10. Room-temperature deposition of crystalline patterned ZnO films by confined dewetting lithography

    Energy Technology Data Exchange (ETDEWEB)

    Sepulveda-Guzman, S., E-mail: selene.sepulvedagz@uanl.edu.mx [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reeja-Jayan, B. [Texas Materials Institute, University of Texas at Austin, Austin, TX 78712 (United States); De la Rosa, E. [Centro de Investigacion en Optica, Loma del Bosque 115 Col. Lomas del Campestre C.P. 37150 Leon, Gto. Mexico (Mexico); Ortiz-Mendez, U. [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reyes-Betanzo, C. [Instituto Nacional de Astrofisica Optica y Electronica, Calle Luis Enrique Erro No. 1, Santa Maria Tonanzintla, Puebla. Apdo. Postal 51 y 216, C.P. 72000 Puebla (Mexico); Cruz-Silva, R. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, UAEM. Av. Universidad 1001, Col. Chamilpa, CP 62210 Cuernavaca, Mor. (Mexico); Jose-Yacaman, M. [Physics and Astronomy Department University of Texas at San Antonio 1604 campus San Antonio, TX 78249 (United States)

    2010-03-15

    In this work patterned ZnO films were prepared at room-temperature by deposition of {approx}5 nm size ZnO nanoparticles using confined dewetting lithography, a process which induces their assembly, by drying a drop of ZnO colloidal dispersion between a floating template and the substrate. Crystalline ZnO nanoparticles exhibit a strong visible (525 nm) light emission upon UV excitation ({lambda} = 350 nm). The resulting films were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The method described herein presents a simple and low cost method to prepare crystalline ZnO films with geometric patterns without additional annealing. Such transparent conducting films are attractive for applications like light emitting diodes (LEDs). As the process is carried out at room temperature, the patterned crystalline ZnO films can even be deposited on flexible substrates.

  11. Room temperature current injection polariton light emitting diode with a hybrid microcavity.

    Science.gov (United States)

    Lu, Tien-Chang; Chen, Jun-Rong; Lin, Shiang-Chi; Huang, Si-Wei; Wang, Shing-Chung; Yamamoto, Yoshihisa

    2011-07-13

    The strong light-matter interaction within a semiconductor high-Q microcavity has been used to produce half-matter/half-light quasiparticles, exciton-polaritons. The exciton-polaritons have very small effective mass and controllable energy-momentum dispersion relation. These unique properties of polaritons provide the possibility to investigate the fundamental physics including solid-state cavity quantum electrodynamics, and dynamical Bose-Einstein condensates (BECs). Thus far the polariton BEC has been demonstrated using optical excitation. However, from a practical viewpoint, the current injection polariton devices operating at room temperature would be most desirable. Here we report the first realization of a current injection microcavity GaN exciton-polariton light emitting diode (LED) operating under room temperature. The exciton-polariton emission from the LED at photon energy 3.02 eV under strong coupling condition is confirmed through temperature-dependent and angle-resolved electroluminescence spectra.

  12. Towards an Einstein-Podolsky-Rosen paradox between two macroscopic atomic ensembles at room temperature

    Science.gov (United States)

    He, Q. Y.; Reid, M. D.

    2013-06-01

    Experiments have reported the entanglement of two spatially separated macroscopic atomic ensembles at room temperature (Krauter et al 2011 Phys. Rev. Lett. 107 080503; Julsgaard et al 2001 Nature 413 400). We show how an Einstein-Podolsky-Rosen (EPR) paradox is realizable with this experiment. Our proposed test involves violation of an inferred Heisenberg uncertainty principle, which is a sufficient condition for an EPR paradox. This is a stronger test of nonlocality than entanglement. Our proposal would enable the first definitive confirmation of quantum EPR paradox correlations between two macroscopic objects at room temperature. This is a necessary intermediate step towards a nonlocal experiment with causal measurement separations. As well as having fundamental significance, the realization of an atomic EPR paradox could provide a resource for novel applications in quantum technology.

  13. Room-Temperature Quantum Ballistic Transport in Monolithic Ultrascaled Al-Ge-Al Nanowire Heterostructures.

    Science.gov (United States)

    Sistani, Masiar; Staudinger, Philipp; Greil, Johannes; Holzbauer, Martin; Detz, Hermann; Bertagnolli, Emmerich; Lugstein, Alois

    2017-08-09

    Conductance quantization at room temperature is a key requirement for the utilizing of ballistic transport for, e.g., high-performance, low-power dissipating transistors operating at the upper limit of "on"-state conductance or multivalued logic gates. So far, studying conductance quantization has been restricted to high-mobility materials at ultralow temperatures and requires sophisticated nanostructure formation techniques and precise lithography for contact formation. Utilizing a thermally induced exchange reaction between single-crystalline Ge nanowires and Al pads, we achieved monolithic Al-Ge-Al NW heterostructures with ultrasmall Ge segments contacted by self-aligned quasi one-dimensional crystalline Al leads. By integration in electrostatically modulated back-gated field-effect transistors, we demonstrate the first experimental observation of room temperature quantum ballistic transport in Ge, favorable for integration in complementary metal-oxide-semiconductor platform technology.

  14. Room-temperature deposition of crystalline patterned ZnO films by confined dewetting lithography

    International Nuclear Information System (INIS)

    Sepulveda-Guzman, S.; Reeja-Jayan, B.; De la Rosa, E.; Ortiz-Mendez, U.; Reyes-Betanzo, C.; Cruz-Silva, R.; Jose-Yacaman, M.

    2010-01-01

    In this work patterned ZnO films were prepared at room-temperature by deposition of ∼5 nm size ZnO nanoparticles using confined dewetting lithography, a process which induces their assembly, by drying a drop of ZnO colloidal dispersion between a floating template and the substrate. Crystalline ZnO nanoparticles exhibit a strong visible (525 nm) light emission upon UV excitation (λ = 350 nm). The resulting films were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The method described herein presents a simple and low cost method to prepare crystalline ZnO films with geometric patterns without additional annealing. Such transparent conducting films are attractive for applications like light emitting diodes (LEDs). As the process is carried out at room temperature, the patterned crystalline ZnO films can even be deposited on flexible substrates.

  15. Towards an Einstein–Podolsky–Rosen paradox between two macroscopic atomic ensembles at room temperature

    International Nuclear Information System (INIS)

    He, Q Y; Reid, M D

    2013-01-01

    Experiments have reported the entanglement of two spatially separated macroscopic atomic ensembles at room temperature (Krauter et al 2011 Phys. Rev. Lett. 107 080503; Julsgaard et al 2001 Nature 413 400). We show how an Einstein–Podolsky–Rosen (EPR) paradox is realizable with this experiment. Our proposed test involves violation of an inferred Heisenberg uncertainty principle, which is a sufficient condition for an EPR paradox. This is a stronger test of nonlocality than entanglement. Our proposal would enable the first definitive confirmation of quantum EPR paradox correlations between two macroscopic objects at room temperature. This is a necessary intermediate step towards a nonlocal experiment with causal measurement separations. As well as having fundamental significance, the realization of an atomic EPR paradox could provide a resource for novel applications in quantum technology. (paper)

  16. Room temperature strong coupling effects from single ZnO nanowire microcavity

    KAUST Repository

    Das, Ayan

    2012-05-01

    Strong coupling effects in a dielectric microcavity with a single ZnO nanowire embedded in it have been investigated at room temperature. A large Rabi splitting of ?100 meV is obtained from the polariton dispersion and a non-linearity in the polariton emission characteristics is observed at room temperature with a low threshold of 1.63 ?J/cm2, which corresponds to a polariton density an order of magnitude smaller than that for the Mott transition. The momentum distribution of the lower polaritons shows evidence of dynamic condensation and the absence of a relaxation bottleneck. The polariton relaxation dynamics were investigated by timeresolved measurements, which showed a progressive decrease in the polariton relaxation time with increase in polariton density. © 2012 Optical Society of America.

  17. Stress-induced phase transformation and room temperature aging in Ti-Nb-Fe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cai, S.; Schaffer, J.E. [Fort Wayne Metals Research Products Corp, 9609 Ardmore Ave., Fort Wayne, IN 46809 (United States); Ren, Y. [Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)

    2017-01-05

    Room temperature deformation behavior of Ti-17Nb-1Fe and Ti-17Nb-2Fe alloys was studied by synchrotron X-ray diffraction and tensile testing. It was found that, after proper heat treatment, both alloys were able to recover a deformation strain of above 3.5% due to the Stress-induced Martensite (SIM) phase transformation. Higher Fe content increased the beta phase stability and onset stress for SIM transformation. A strong {110}{sub β} texture was produced in Ti-17Nb-2Fe compared to the {210}{sub β} texture that was observed in Ti-17Nb-1Fe. Room temperature aging was observed in both alloys, where the formation of the omega phase increased the yield strength (also SIM onset stress), and decreased the ductility and strain recovery. Other metastable beta Ti alloys may show a similar aging response and this should draw the attention of materials design engineers.

  18. Defect controlled room temperature ferromagnetism in Co-doped barium titanate nanocrystals

    International Nuclear Information System (INIS)

    Ray, Sugata; Kolen'ko, Yury V; Watanabe, Tomoaki; Yoshimura, Masahiro; Itoh, Mitsuru; Kovnir, Kirill A; Lebedev, Oleg I; Turner, Stuart; Erni, Rolf; Tendeloo, Gustaaf Van; Chakraborty, Tanushree

    2012-01-01

    Defect mediated high temperature ferromagnetism in oxide nanocrystallites is the central feature of this work. Here, we report the development of room temperature ferromagnetism in nanosized Co-doped barium titanate particles with a size of around 14 nm, synthesized by a solvothermal drying method. A combination of x-ray diffraction with state-of-the-art electron microscopy techniques confirms the intrinsic doping of Co into BaTiO 3 . The development of the room temperature ferromagnetism was tracked down to the different donor defects, namely hydroxyl groups at the oxygen site and oxygen vacancies and their relative concentrations at the surface and the core of the nanocrystal, which could be controlled by post-synthesis drying and thermal treatments.

  19. The effects of nanoscale geometry and spillover on room temperature storage of hydrogen on silica nanosprings

    International Nuclear Information System (INIS)

    Corti, Giancarlo; Zhan, Yingqian; Wang, Lidong; Hare, Brian; Cantrell, Timothy; II, Miles Beaux; Prakash, Tej; Ytreberg, F Marty; McIlroy, David N; Miller, Michael A

    2013-01-01

    Silica nanosprings (NSs) consisting of multiple nanowires intertwined were demonstrated to reversibly store 0.85 wt% hydrogen at 20 bar and room temperature. X-ray photoelectron spectroscopy indicates a mixed 3 + –4 + ionization state of the silicon atoms and partially explains the enhanced surface adsorption of H 2 relative to other forms of silica. Theoretical modeling and simulation using a Lennard-Jones potential demonstrated that interstitial sites between the silica nanowires forming the NS are energetically more favorable adsorption sites relative to single nanowires. The addition of Pd nanoparticles to the surface of the silica NSs was demonstrated to increase the hydrogen storage capacity to ≈3.5 wt% at 66 bar and room temperature. Palladium-nanoparticle-induced hydrogen spillover is attributed to the enhanced storage capacity relative to bare silica NSs. (paper)

  20. Deposition of silicon oxynitride films by low energy ion beam assisted nitridation at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Youroukov, S; Kitova, S; Danev, G [Central Laboratory of Photoprocesses, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 109, 113 Sofia (Bulgaria)], E-mail: skitova@clf.bas.bg

    2008-05-01

    The possibility is studied of growing thin silicon oxynitride films by e-gun evaporation of SiO and SiO{sub 2} together with concurrent bombardment with low energy N{sub 2}{sup +} ions from a cyclotron resonance (ECR) source at room temperature of substrates. The degree of nitridation and oxidation of the films is investigated by means of X-ray spectroscopy. The optical characteristics of the films, their environmental stability and adhesion to different substrates are examined. The results obtained show than the films deposited are transparent. It is found that in the case of SiO evaporation with concurrent N{sub 2}{sup +} ion bombardment, reactive implantation of nitrogen within the films takes place at room temperature of the substrate with the formation of a new silicon oxynitride compound even at low ion energy (150-200 eV)

  1. Deposition of silicon oxynitride films by low energy ion beam assisted nitridation at room temperature

    Science.gov (United States)

    Youroukov, S.; Kitova, S.; Danev, G.

    2008-05-01

    The possibility is studied of growing thin silicon oxynitride films by e-gun evaporation of SiO and SiO2 together with concurrent bombardment with low energy N2+ ions from a cyclotron resonance (ECR) source at room temperature of substrates. The degree of nitridation and oxidation of the films is investigated by means of X-ray spectroscopy. The optical characteristics of the films, their environmental stability and adhesion to different substrates are examined. The results obtained show than the films deposited are transparent. It is found that in the case of SiO evaporation with concurrent N2+ ion bombardment, reactive implantation of nitrogen within the films takes place at room temperature of the substrate with the formation of a new silicon oxynitride compound even at low ion energy (150-200 eV).

  2. Nickel in silicon: Room-temperature in-diffusion and interaction with radiation defects

    Energy Technology Data Exchange (ETDEWEB)

    Yarykin, Nikolai [Institute of Microelectronics Technology, RAS, Chernogolovka (Russian Federation); Weber, Joerg [Technische Universitaet Dresden (Germany)

    2017-07-15

    Nickel is incorporated into silicon wafers during chemomechanical polishing in an alkaline Ni-contaminated slurry at room temperature. The nickel in-diffusion is detected by DLTS depth profiles of a novel Ni{sub 183} level, which is formed due to a reaction between the diffusing nickel and the VO centers introduced before the polishing. The Ni{sub 183} profile extends up to 10 μm after a 2 min polishing. The available data provide a lower estimate for the room-temperature nickel diffusivity D{sub Ni} > 10{sup -9} cm{sup 2} s{sup -1}. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. A highly reversible room-temperature lithium metal battery based on crosslinked hairy nanoparticles.

    KAUST Repository

    Choudhury, Snehashis; Mangal, Rahul; Agrawal, Akanksha; Archer, Lynden A

    2015-01-01

    Rough electrodeposition, uncontrolled parasitic side-reactions with electrolytes and dendrite-induced short-circuits have hindered development of advanced energy storage technologies based on metallic lithium, sodium and aluminium electrodes. Solid polymer electrolytes and nanoparticle-polymer composites have shown promise as candidates to suppress lithium dendrite growth, but the challenge of simultaneously maintaining high mechanical strength and high ionic conductivity at room temperature has so far been unmet in these materials. Here we report a facile and scalable method of fabricating tough, freestanding membranes that combine the best attributes of solid polymers, nanocomposites and gel-polymer electrolytes. Hairy nanoparticles are employed as multifunctional nodes for polymer crosslinking, which produces mechanically robust membranes that are exceptionally effective in inhibiting dendrite growth in a lithium metal battery. The membranes are also reported to enable stable cycling of lithium batteries paired with conventional intercalating cathodes. Our findings appear to provide an important step towards room-temperature dendrite-free batteries.

  4. Flake like V_2O_5 nanoparticles for ethanol sensing at room temperature

    International Nuclear Information System (INIS)

    Chitra, M.; Uthayarani, K.; Rajasekaran, N.; Neelakandeswari, N.; Girija, E. K.; Padiyan, D. Pathinettam

    2016-01-01

    The versatile redox property of vanadium oxide explores it in various applications like catalysis, electrochromism, electrochemistry, energy storage, sensors, microelectronics, batteries etc., In this present work, vanadium oxide was prepared via hydrothermal route followed by calcination. The structural and lattice parameters were analysed from the powder X-ray diffraction (XRD) pattern. The morphology and the composition of the sample were obtained from Field emission Scanning electron microscopic (FeSEM) and Energy Dispersive X-ray (EDAX) Spectrometric analysis respectively. The sensitivity, response – recovery time of the sample towards ethanol (0 ppm – 300 ppm) sensing at room temperature was measured and the present investigation on vanadium oxide nanoparticles over the flakes shows better sensitivity (30%) at room temperature.

  5. Designing switchable near room-temperature multiferroics via the discovery of a novel magnetoelectric coupling

    Science.gov (United States)

    Feng, J. S.; Xu, Ke; Bellaiche, Laurent; Xiang, H. J.

    2018-05-01

    Magnetoelectric (ME) coupling is the key ingredient for realizing the cross-control of magnetism and ferroelectricity in multiferroics. However, multiferroics are not only rare, especially at room-temperature, in nature but also the overwhelming majority of known multiferroics do not exhibit highly-desired switching of the direction of magnetization when the polarization is reversed by an electric field. Here, we report group theory analysis and ab initio calculations demonstrating, and revealing the origin of, the existence of a novel form of ME coupling term in a specific class of materials that does allow such switching. This term naturally explains the previously observed electric field control of magnetism in the first known multiferroics, i.e., the Ni–X boracite family. It is also presently used to design a switchable near room-temperature multiferroic (namely, LaSrMnOsO6 perovskite) having rather large ferroelectric polarization and spontaneous magnetization, as well as strong ME coupling.

  6. Mechanical Behaviour of 304 Austenitic Stainless Steel Processed by Room Temperature Rolling

    Science.gov (United States)

    Singh, Rahul; Goel, Sunkulp; Verma, Raviraj; Jayaganthan, R.; Kumar, Abhishek

    2018-03-01

    To study the effect of room temperature rolling on mechanical properties of 304 Austenitic Stainless Steel, the as received 304 ASS was rolled at room temperature for different percentage of plastic deformation (i.e. 30, 50, 70 and 90 %). Microstructural study, tensile and hardness tests were performed in accordance with ASTM standards to study the effect of rolling. The ultimate tensile strength (UTS) and hardness of a rolled specimen have enhanced with rolling. The UTS has increased from 693 MPa (as received) to 1700 MPa (after 90% deformation). The improvement in UTS of processed samples is due to combined effect of grain refinement and stress induced martensitic phase transformation. The hardness values also increases from 206 VHN (as received) to 499 VHN (after 90% deformation). Magnetic measurements were also conducted to confirm the formation of martensitic phase.

  7. Simulating the room-temperature dynamic motion of a ferromagnetic vortex in a bistable potential

    Science.gov (United States)

    Haber, E.; Badea, R.; Berezovsky, J.

    2018-05-01

    The ability to precisely and reliably control the dynamics of ferromagnetic (FM) vortices could lead to novel nonvolatile memory devices and logic gates. Intrinsic and fabricated defects in the FM material can pin vortices and complicate the dynamics. Here, we simulated switching a vortex between bistable pinning sites using magnetic field pulses. The dynamic motion was modeled with the Thiele equation for a massless, rigid vortex subject to room-temperature thermal noise. The dynamics were explored both when the system was at zero temperature and at room-temperature. The probability of switching for different pulses was calculated, and the major features are explained using the basins of attraction map of the two pinning sites.

  8. A highly reversible room-temperature lithium metal battery based on crosslinked hairy nanoparticles.

    KAUST Repository

    Choudhury, Snehashis

    2015-12-04

    Rough electrodeposition, uncontrolled parasitic side-reactions with electrolytes and dendrite-induced short-circuits have hindered development of advanced energy storage technologies based on metallic lithium, sodium and aluminium electrodes. Solid polymer electrolytes and nanoparticle-polymer composites have shown promise as candidates to suppress lithium dendrite growth, but the challenge of simultaneously maintaining high mechanical strength and high ionic conductivity at room temperature has so far been unmet in these materials. Here we report a facile and scalable method of fabricating tough, freestanding membranes that combine the best attributes of solid polymers, nanocomposites and gel-polymer electrolytes. Hairy nanoparticles are employed as multifunctional nodes for polymer crosslinking, which produces mechanically robust membranes that are exceptionally effective in inhibiting dendrite growth in a lithium metal battery. The membranes are also reported to enable stable cycling of lithium batteries paired with conventional intercalating cathodes. Our findings appear to provide an important step towards room-temperature dendrite-free batteries.

  9. Heavy atom enhanced room-temperature phosphorimetry for ultratrace determination of harmane

    Directory of Open Access Journals (Sweden)

    Flávia F. de Carvalho Marques

    2008-01-01

    Full Text Available Harmane has been proposed for the treatment of epilepsy, AIDS and leshmaniosis. Its room-temperature phosphorescence was induced using either AgNO3 or TlNO3, enabling absolute limits of detection of 0.12 and 2.4 ng respectively, with linear dynamic ranges extending up to 456 ng (AgNO3 and 911 ng (TlNO3. Relative standard deviations around 3% were observed for substrates containing 46 ng of harmane. Such sensitivity and precision are needed because harmane intake must be strictly controlled to achieve proper therapeutic response. Interference studies were performed using thalidomide, reserpine and yohimbine. Recovery of 104±6% was achieved using solid surface room-temperature phosphorimetry. The result was comparable to the one obtained by micellar electrokinetic chromatography.

  10. Physicochemical, spectroscopic and electrochemical characterization of magnesium ion-conducting, room temperature, ternary molten electrolytes

    Science.gov (United States)

    Narayanan, N. S. Venkata; Ashok Raj, B. V.; Sampath, S.

    Room temperature, magnesium ion-conducting molten electrolytes are prepared using a combination of acetamide, urea and magnesium triflate or magnesium perchlorate. The molten liquids show high ionic conductivity, of the order of mS cm -1 at 298 K. Vibrational spectroscopic studies based on triflate/perchlorate bands reveal that the free ion concentration is higher than that of ion-pairs and aggregates in the melt. Electrochemical reversibility of magnesium deposition and dissolution is demonstrated using cyclic voltammetry and impedance studies. The transport number of Mg 2+ ion determined by means of a combination of d.c. and a.c. techniques is ∼0.40. Preliminary studies on the battery characteristics reveal good capacity for the magnesium rechargeable cell and open up the possibility of using this unique class of acetamide-based room temperature molten electrolytes in secondary magnesium batteries.

  11. Droplet-fused microreactors for room temperature synthesis of nanoscale needle-like hydroxyapatite

    International Nuclear Information System (INIS)

    Liu Kaiying; Qin Jianhua

    2013-01-01

    A microfluidic device using droplet-fused microreactors is introduced for room temperature synthesis of nanoscale needle-shaped hydroxyapatite (HAp, Ca 10 (PO 4 ) 6 (OH) 2 ). The device is integrated with multifunctional units, e.g., T-junctions for droplet generation and fusion, winding channels for rapid mixing, and a delay line for simple visualization of the HAp formation process. The necessary conditions such as surfactant and fluid flow rate for an aqueous stream to merge with water-in-oil droplets are investigated. The nanoscale morphologies of the HAp produced by this method are also compared with HAp prepared by conventional bulk mixing. This paper shows that further reaction could be initiated by flowing additional reagent streams directly into the droplets of the initial reaction mixture, which is a novel approach for synthesizing a needle-like morphology of the HAp with a high aspect ratio under room temperature. (paper)

  12. Tannic acid assisted synthesis of flake-like hydroxyapatite nanostructures at room temperature

    Science.gov (United States)

    Vázquez, Maricela Santana; Estevez, O.; Ascencio-Aguirre, F.; Mendoza-Cruz, R.; Bazán-Díaz, L.; Zorrila, C.; Herrera-Becerra, R.

    2016-09-01

    A simple and non-expensive procedure was performed to synthesize hydroxyapatite (HAp) flake-like nanostructures, by using a co-precipitation method with tannic acid as stabilizing agent at room temperature and freeze drying. Samples were synthesized with two different salts, Ca(NO3)2 and CaCl2. X-ray diffraction analysis, Raman spectroscopy, scanning and transmission electron microscopy characterizations reveal Ca10(PO4)6(OH)2 HAp particles with hexagonal structure and P63/m space group in both cases. In addition, the particle size was smaller than 20 nm. The advantage of this method over the works reported to date lies in the ease for obtaining HAp particles with a single morphology (flakes), in high yield. This opens the possibility of expanding the view to the designing of new composite materials based on the HAp synthesized at room temperature.

  13. Room Temperature Magnetic Determination of the Current Center Line for the ITER TF Coils

    CERN Document Server

    Lerch, Philippe; Buzio, Marco; Negrazus, Marco; Baynham, Elwyn; Sanfilippo, Stephane; Foussat, Arnaud

    2014-01-01

    The ITER tokamak includes 18 superconducting D-shaped toroidal field (IT) coils. Unavoidable shape deformations as well as assembly errors will lead to field errors, which can be modeled with the knowledge of the current center line (CCL). Accurate survey during the entire manufacturing and assembly process, including transfer of survey points, is complex. In order to increase the level of confidence, a room temperature magnetic measurement of the CCL on assembled and closed winding packs is foreseen, prior to insertion into their cold case. In this contribution, we discuss the principle of the CCL determination and present a low frequency ac measurement system under development at PSI, within an ITER framework contract. The largest current allowed to flow in the TF coil at room temperature and the precision requirements for the determination of the CCL loci of the coil are hard boundaries. Eddy currents in the radial plates, the winding pack enclosures, and possibly from iron in the reinforced concrete floor...

  14. Room temperature RF characterization of Nb make super conducting radio frequency cavities at RRCAT

    International Nuclear Information System (INIS)

    Mahawar, Ashish; Mohania, Praveen; Shrivastava, Purushottam; Yadav, Anand; Puntambekar, Avinash

    2015-01-01

    In order to ensure that the final welded Nb superconducting RF cavities are at the correct frequency the cavity structures are measured at various development stages for their resonant frequency. These measurements are performed at room temperature using a cavity measurement setup developed in house and a VNA. These measurements are critical to identify the length a cavity structure needs to be trimmed before welding. Measurement of resonant frequencies of Nb made cavity structures were performed for half cell, dumb bell, single cell, long end cell and short end cell structures. These structures were then joined to develop single cell and multi-cell 650 MHz/1300 MHz cavities. The present paper describes room temperature cavity characterization being carried out at RRCAT. (author)

  15. Heavy metal ternary halides for room-temperature x-ray and gamma-ray detection

    Science.gov (United States)

    Liu, Zhifu; Peters, John A.; Stoumpos, Constantinos C.; Sebastian, Maria; Wessels, Bruce W.; Im, Jino; Freeman, Arthur J.; Kanatzidis, Mercouri G.

    2013-09-01

    We report our recent progress on wide bandgap ternary halide compounds CsPbBr3 and CsPbCl3 for room temperature x-ray and gamma-ray detectors. Their bandgaps are measured to be 2.24 eV and 2.86 eV, respectively. The measured mobility-lifetime products of CsPbBr3 are 1.7×10-3, 1.3×10-3 cm2/V, for electron and hole carriers, respectively, comparable to those of CdTe. We measured the room temperature spectral response of CsPbBr3 sample to Ag x-ray radiation. It has a well-resolved spectral response to the 22.4 keV Kα radiation peak and detector efficiency comparable to that of CdZnTe detector at 295 K.

  16. A room-temperature non-volatile CNT-based molecular memory cell

    Science.gov (United States)

    Ye, Senbin; Jing, Qingshen; Han, Ray P. S.

    2013-04-01

    Recent experiments with a carbon nanotube (CNT) system confirmed that the innertube can oscillate back-and-forth even under a room-temperature excitation. This demonstration of relative motion suggests that it is now feasible to build a CNT-based molecular memory cell (MC), and the key to bring the concept to reality is the precision control of the moving tube for sustained and reliable read/write (RW) operations. Here, we show that by using a 2-section outertube design, we are able to suitably recalibrate the system energetics and obtain the designed performance characteristics of a MC. Further, the resulting energy modification enables the MC to operate as a non-volatile memory element at room temperatures. Our paper explores a fundamental understanding of a MC and its response at the molecular level to roadmap a novel approach in memory technologies that can be harnessed to overcome the miniaturization limit and memory volatility in memory technologies.

  17. Room temperature ferromagnetism in Fe-doped semiconductor ZrS2 single crystals

    Science.gov (United States)

    Muhammad, Zahir; Lv, Haifeng; Wu, Chuanqiang; Habib, Muhammad; Rehman, Zia ur; Khan, Rashid; Chen, Shuangming; Wu, Xiaojun; Song, Li

    2018-04-01

    Two dimensional (2D) layered magnetic materials have obtained much attention due to their intriguing properties with a potential application in the field of spintronics. Herein, room-temperature ferromagnetism with 0.2 emu g‑1 magnetic moment is realized in Fe-doped ZrS2 single crystals of millimeter size, in comparison with diamagnetic behaviour in ZrS2. The electron paramagnetic resonance spectroscopy reveals that 5.2wt% Fe-doping ZrS2 crystal exhibit high spin value of g-factor about 3.57 at room temperature also confirmed this evidence, due to the unpaired electrons created by doped Fe atoms. First principle static electronic and magnetic calculations further confirm the increased stability of long range ferromagnetic ordering and enhanced magnetic moment in Fe-doped ZrS2, originating from the Fe spin polarized electron near the Fermi level.

  18. Electrochemical characterization of Uranyl-TODGA complex in a room temperature ionic liquid

    International Nuclear Information System (INIS)

    Sengupta, Arijit; Murali, M.S.; Mohapatra, P.K.

    2014-01-01

    Room temperature ionic liquids are new materials finding extensive use in many applications such as syntheses, catalysis, electrochemistry etc. including separation science. Some of them are known as green solvents set to be environment-friendly. With a view to apply the favourable properties of these neoteric solvents to separation science in nuclear related fields such as reprocessing and waste remediation, electrochemical characterization of the metal ions encountered in above fields e.g. U(VI), Pu(IV), Np(IV), Am(III) etc. their complexes with the ligands often becomes necessary and useful. In the present piece of work, electrochemical characterization has been carried out by cyclic voltammetry of uranyl complex with one of the most promising trivalent actinide extractants, namely, tetraoctyldiglycolamide (TODGA) dissolved/extracted into a room temperature ionic liquid, 1-methyl-3-octyl imidazolium bis(trifluoro methylsulphonyl) imide (C 8 mimNTf 2 )

  19. Room temperature ferromagnetism in nano-crystalline Co:ThO2 powders

    International Nuclear Information System (INIS)

    Bhide, M.K.; Kadam, R.M.; Godbole, S.V.; Tyagi, A.K.; Salunke, H.G.

    2012-01-01

    The major interest in dilute magnetic semiconductors (DMS's) had been directed towards the synthesis of room temperature ferromagnetic (RTF) materials for their potential applications in spintronic devices. Room temperature (RT) ferromagnetism was initially reported in Co doped TiO 2 , ZnO 2 and SnO 2 thin films and in the recent past in transition metal doped wide band gap materials. In the present paper we report the synthesis of Co doped ThO 2 nano powders by urea combustion method. The XRD characterization of 300℃ annealed samples confirmed formation of ThO 2 in the cubic phase and the average crystallite size obtained using Scherrer's formula was around 6 nm

  20. Ab-initio calculation and experimental observation of room temperature ferromagnetism in 50 keV nitrogen implanted rutile TiO2

    Science.gov (United States)

    Luitel, Homnath; Chakrabarti, Mahuya; Sarkar, A.; Dechoudhury, S.; Bhowmick, D.; Naik, V.; Sanyal, D.

    2018-02-01

    Room temperature magnetic properties of 50 keV N4+ ion beam implanted rutile TiO2 have been theoretically and experimentally studied. Ab-initio calculation under the frame work of density functional theory has been carried out to study the magnetic properties of the different possible nitrogen related defects in TiO2. Spin polarized density of states calculation suggests that both Ninst and NO can induce ferromagnetic ordering in rutile TiO2. In both cases the 2p orbital electrons of nitrogen atom give rise to the magnetic moment in TiO2. The possibility of the formation of N2 molecule in TiO2 system is also studied but in this case no significant magnetic moment has been observed. The magnetic measurements, using SQUID magnetometer, results a ferromagnetic ordering even at room temperature for the 50 keV N4+ ion beam implanted rutile TiO2.

  1. Observation of room temperature ferromagnetism in ZnTe:Cr films grown onto glass substrate by thermal evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Soundararajan, D; Mangalaraj, D; Nataraj, D [Thin Film Laboratory, Department of Physics, Bharathiar University, Coimbatore -641 046 (India); Dorosinskii, L [National Institute of Metrology (TUBITAK -UME), P.K. 54, 41470, Gebze -Kocaeli (Turkey); Santoyo-Salazar, J, E-mail: dorosins@ume.tubitak.gov.t [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, Mexico D.F. 04510 (Mexico)

    2009-03-01

    ZnTe and ZnTe:Cr films were prepared onto glass substrates using thermal evaporation method. Structural properties of the prepared samples were analyzed using X-ray diffractometer, and the presence of ZnCrTe phase was identified along with poor crystallinity. Composition analysis was done using XPS and the Cr content in the film was found to be 0.05 atomic percent. Transmittance spectra were recorded using UV-Vis spectrophotometer. The valence state of Cr in ZnTe:Cr film is determined to be +2 using electron spin resonance (ESR) spectroscopy. Magnetic moment data as a function of magnetic field were recorded using Superconducting Quantum Interference Device (SQUID) magnetometer at temperatures 5, 77 and 300 K. The results showed minority ferromagnetic behavior even at room temperature. Magnetic domains were observed using Magnetic Force Microscopy and the average value of domain size is 3.7 nm.

  2. A kinematic hardening constitutive model for the uniaxial cyclic stress-strain response of magnesium sheet alloys at room temperature

    Science.gov (United States)

    He, Zhitao; Chen, Wufan; Wang, Fenghua; Feng, Miaolin

    2017-11-01

    A kinematic hardening constitutive model is presented, in which a modified form of von Mises yield function is adopted, and the initial asymmetric tension and compression yield stresses of magnesium (Mg) alloys at room temperature (RT) are considered. The hardening behavior was classified into slip, twinning, and untwinning deformation modes, and these were described by two forms of back stress to capture the mechanical response of Mg sheet alloys under cyclic loading tests at RT. Experimental values were obtained for AZ31B-O and AZ31B sheet alloys under both tension-compression-tension (T-C-T) and compression-tension (C-T) loadings to calibrate the parameters of back stresses in the proposed model. The predicted parameters of back stresses in the twinning and untwinning modes were expressed as a cubic polynomial. The predicted curves based on these parameters showed good agreement with the tests.

  3. Simple and Efficient Generation of Aryl Radicals from Aryl Triflates: Synthesis of Aryl Boronates and Aryl Iodides at Room Temperature.

    Science.gov (United States)

    Liu, Wenbo; Yang, Xiaobo; Gao, Yang; Li, Chao-Jun

    2017-06-28

    Despite the wide use of aryl radicals in organic synthesis, current methods to prepare them from aryl halides, carboxylic acids, boronic acids, and diazonium salts suffer from limitations. Aryl triflates, easily obtained from phenols, are promising aryl radical progenitors but remain elusive in this regard. Inspired by the single electron transfer process for aryl halides to access aryl radicals, we developed a simple and efficient protocol to convert aryl triflates to aryl radicals. Our success lies in exploiting sodium iodide as the soft electron donor assisted by light. This strategy enables the scalable synthesis of two types of important organic molecules, i.e., aryl boronates and aryl iodides, in good to high yields, with broad functional group compatibility in a transition-metal-free manner at room temperature. This protocol is anticipated to find potential applications in other aryl-radical-involved reactions by using aryl triflates as aryl radical precursors.

  4. The Effect of Grain Size and Strain on the Tensile Flow Stress of Aluminium at Room Temperature

    DEFF Research Database (Denmark)

    Hansen, Niels

    1977-01-01

    stress-grain size relationship was analyzed in terms of matrix strengthening and grain boundary strengthening according to the dislocation concept of Ashby. At intermediate strains this approach gives a good description of the effect of strain, grain size and purity on the flow stress.......Tensile-stress-strain data over a strain range from 0.2 to 30% were obtained at room temperature for 99.999 and 99.5% aluminium as a function of grain size. The yield stress-grain size relationship can be expressed by a Petch-Hall relation with approximately the same slope for the two materials....... The flow stress-grain size relationship can adequately be expressed by a modified Petch-Hall relation; for 99.999% aluminium material the slope increases with strain through a maximum around 15–20%, whereas for 99.5% aluminium the slope decreases with the strain to zero at strains about 10%. The flow...

  5. Room temperature inductively coupled plasma etching of InAs/InSb in BCl 3/Cl 2/Ar

    KAUST Repository

    Sun, Jian

    2012-10-01

    Inductively coupled plasma (ICP) etching of InAs and InSb at room temperature has been investigated using BCl 3/Cl 2/Ar plasma. Specifically, the etch rate and post-etching surface morphology were investigated as functions of the gas composition, ICP power, process pressure, and RF chuck power. An optimized process has been developed, yielding anisotropic etching and very smooth surfaces with roughnesses of 0.25 nm for InAs, and 0.57 nm for InSb, which is comparable with the surface of epi-ready polished wafers. The process provides moderate etching rates of 820 /min for InAs and 2800 /min for InSb, and the micro-masking effect is largely avoided. © 2012 Elsevier B.V. All rights reserved.

  6. Structural and functional characterization of a multifunctional alanine-rich peptide analogue from Pleuronectes americanus.

    Directory of Open Access Journals (Sweden)

    Ludovico Migliolo

    Full Text Available Recently, defense peptides that are able to act against several targets have been characterized. The present work focuses on structural and functional evaluation of the peptide analogue Pa-MAP, previously isolated as an antifreeze peptide from Pleuronectes americanus. Pa-MAP showed activities against different targets such as tumoral cells in culture (CACO-2, MCF-7 and HCT-116, bacteria (Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 25923, viruses (HSV-1 and HSV-2 and fungi (Candida parapsilosis ATCC 22019, Trichophyton mentagrophytes (28d&E and T. rubrum (327. This peptide did not show toxicity against mammalian cells such as erythrocytes, Vero and RAW 264.7 cells. Molecular mechanism of action was related to hydrophobic residues, since only the terminal amino group is charged at pH 7 as confirmed by potentiometric titration. In order to shed some light on its structure-function relations, in vitro and in silico assays were carried out using circular dichroism and molecular dynamics. Furthermore, Pa-MAP showed partial unfolding of the peptide changes in a wide pH (3 to 11 and temperature (25 to 95°C ranges, although it might not reach complete unfolding at 95°C, suggesting a high conformational stability. This peptide also showed a conformational transition with a partial α-helical fold in water and a full α-helical core in SDS and TFE environments. These results were corroborated by spectral data measured at 222 nm and by 50 ns dynamic simulation. In conclusion, data reported here show that Pa-MAP is a potential candidate for drug design against pathogenic microorganisms due to its structural stability and wide activity against a range of targets.

  7. A phase transition close to room temperature in BiFeO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kreisel, J; Jadhav, P; Chaix-Pluchery, O [Laboratoire des Materiaux et du Genie Physique, Grenoble INP, CNRS, Minatec, 3, parvis Louis Neel, 38016 Grenoble (France); Varela, M [Departamento Fisica Aplicada i Optica, Universitat de Barcelona, Carrer MartI i Franques 1. 08028 Campus UAB, Bellaterra 08193 (Spain); Dix, N; Sanchez, F; Fontcuberta, J, E-mail: jens.kreisel@grenoble-inp.fr [Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193 (Spain)

    2011-08-31

    BiFeO{sub 3} (BFO) multiferroic oxide has a complex phase diagram that can be mapped by using appropriately substrate-induced strain in epitaxial films. By using Raman spectroscopy, we conclusively show that films of the so-called supertetragonal T-BFO phase, stabilized under compressive strain, display a reversible temperature-induced phase transition at about 100 deg. C, and thus close to room temperature. (fast track communication)

  8. Room temperature growth of ZnO nanorods by hydrothermal synthesis

    Science.gov (United States)

    Tateyama, Hiroki; Zhang, Qiyan; Ichikawa, Yo

    2018-05-01

    The effect of seed layer morphology on ZnO nanorod growth at room temperature was studied via hydrothermal synthesis on seed layers with different thicknesses and further annealed at different temperatures. The change in the thickness and annealing temperature enabled us to control over a diameter of ZnO nanorods which are attributed to the changing of crystallinity and roughness of the seed layers.

  9. Strength evaluation test of pressureless-sintered silicon nitride at room temperature

    Science.gov (United States)

    Matsusue, K.; Takahara, K.; Hashimoto, R.

    1984-01-01

    In order to study strength characteristics at room temperature and the strength evaluating method of ceramic materials, the following tests were conducted on pressureless sintered silicon nitride specimens: bending tests, the three tensile tests of rectangular plates, holed plates, and notched plates, and spin tests of centrally holed disks. The relationship between the mean strength of specimens and the effective volume of specimens are examined using Weibull's theory. The effect of surface grinding on the strength of specimens is discussed.

  10. Research on cw electron accelerators using room-temperature rf structures: Annual report

    International Nuclear Information System (INIS)

    1986-01-01

    This joint NBS-Los Alamos project of ''Research on CW Electron Accelerators Using Room-Temperature RF Structures'' began seven years ago with the goal of developing a technology base for cw electron accelerators. In this report we describe our progress during FY 1986 and present our plans for completion of the project. First, however, it is appropriate to review the past contributions of the project, describe its status, and indicate its future benefits

  11. BF3/nano-γ-Al2O3 Promoted Knoevenagel Condensation at Room Temperature

    Directory of Open Access Journals (Sweden)

    B. F. Mirjalili

    2015-10-01

    Full Text Available The Knoevenagel condensation of aromatic aldehydes with barbituric acid, dimedone and malononitrile occurred in the presence of BF3/nano-γ-Al2O3 at room temperature in ethanol. This catalyst is characterized by powder X-ray diffraction (XRD, fourier transform infrared spectroscopy (FT-IR, thermal gravimetric analysis (TGA, field emission scanning electron microscopy (FESEM and energy-dispersive X-ray spectroscopy (EDS.

  12. Towards Molecular Dynamics Simulations of Chiral Room-Temperature Ionic Liquids

    Czech Academy of Sciences Publication Activity Database

    Lísal, Martin; Chval, Z.; Storch, Jan; Izák, Pavel

    2014-01-01

    Roč. 189, SI (2014), s. 85-94 ISSN 0167-7322 R&D Projects: GA ČR(CZ) GAP106/12/0569; GA MŠk LH12020 Institutional support: RVO:67985858 Keywords : chiral room-temperature ionic liquid * molecular dynamics simulation * non-polarizable fully flexible all-atom force field Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.515, year: 2014

  13. Towards an Einstein-Podolsky-Rosen paradox between two macroscopic atomic ensembles at room temperature

    OpenAIRE

    He, Q Y; Reid, M D

    2013-01-01

    Experiments have reported the entanglement of two spatially separated macroscopic atomic ensembles at room temperature (Krauter et al 2011 Phys. Rev. Lett. 107 080503; Julsgaard et al 2001 Nature 413 400). We show how an Einstein-Podolsky-Rosen (EPR) paradox is realizable with this experiment. Our proposed test involves violation of an inferred Heisenberg uncertainty principle, which is a sufficient condition for an EPR paradox. This is a stronger test of nonlocality than entanglement. Our pr...

  14. Apparatus to measure emissivities of metallic films between 90K and room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Bekeris, V I [Nunez Univ. Nacional (Argentina). Faculdad de Ciencias Exactas Y Naturales; Ramos, E D [Santa Rosa Univ. Nacional (Argentina). Facultad de Ciencias Exactas Y Naturales; Sanchez, D H [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche

    1975-09-01

    The development of multilayer insulations is aerospace and cryogenic required to know the emissivity of the metallic films used as reflective layers. This work describes an emissometer that measures the total hemispherical emissivity of metallic films evaporated on polyester substrates. The apparatus works at liquid oxigen temperatures and permits to get emissivities from 90K to room temperatures within a 15% precision. The emissometer construction and operation are described in detail. Results of measurements done on Single Aluminized Mylar are presented.

  15. Room temperature femtosecond X-ray diffraction of photosystem II microcrystals

    Science.gov (United States)

    Kern, Jan; Alonso-Mori, Roberto; Hellmich, Julia; Tran, Rosalie; Hattne, Johan; Laksmono, Hartawan; Glöckner, Carina; Echols, Nathaniel; Sierra, Raymond G.; Sellberg, Jonas; Lassalle-Kaiser, Benedikt; Gildea, Richard J.; Glatzel, Pieter; Grosse-Kunstleve, Ralf W.; Latimer, Matthew J.; McQueen, Trevor A.; DiFiore, Dörte; Fry, Alan R.; Messerschmidt, Marc; Miahnahri, Alan; Schafer, Donald W.; Seibert, M. Marvin; Sokaras, Dimosthenis; Weng, Tsu-Chien; Zwart, Petrus H.; White, William E.; Adams, Paul D.; Bogan, Michael J.; Boutet, Sébastien; Williams, Garth J.; Messinger, Johannes; Sauter, Nicholas K.; Zouni, Athina; Bergmann, Uwe; Yano, Junko; Yachandra, Vittal K.

    2012-01-01

    Most of the dioxygen on earth is generated by the oxidation of water by photosystem II (PS II) using light from the sun. This light-driven, four-photon reaction is catalyzed by the Mn4CaO5 cluster located at the lumenal side of PS II. Various X-ray studies have been carried out at cryogenic temperatures to understand the intermediate steps involved in the water oxidation mechanism. However, the necessity for collecting data at room temperature, especially for studying the transient steps during the O–O bond formation, requires the development of new methodologies. In this paper we report room temperature X-ray diffraction data of PS II microcrystals obtained using ultrashort (< 50 fs) 9 keV X-ray pulses from a hard X-ray free electron laser, namely the Linac Coherent Light Source. The results presented here demonstrate that the ”probe before destroy” approach using an X-ray free electron laser works even for the highly-sensitive Mn4CaO5 cluster in PS II at room temperature. We show that these data are comparable to those obtained in synchrotron radiation studies as seen by the similarities in the overall structure of the helices, the protein subunits and the location of the various cofactors. This work is, therefore, an important step toward future studies for resolving the structure of the Mn4CaO5 cluster without any damage at room temperature, and of the reaction intermediates of PS II during O–O bond formation. PMID:22665786

  16. Ruthenium(III Chloride Catalyzed Acylation of Alcohols, Phenols, and Thiols in Room Temperature Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Mingzhong Cai

    2009-09-01

    Full Text Available Ruthenium(III chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]. The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.

  17. Amorphous boron nanorod as an anode material for lithium-ion batteries at room temperature.

    Science.gov (United States)

    Deng, Changjian; Lau, Miu Lun; Barkholtz, Heather M; Xu, Haiping; Parrish, Riley; Xu, Meiyue Olivia; Xu, Tao; Liu, Yuzi; Wang, Hao; Connell, Justin G; Smith, Kassiopeia A; Xiong, Hui

    2017-08-03

    We report an amorphous boron nanorod anode material for lithium-ion batteries prepared through smelting non-toxic boron oxide in liquid lithium. Boron in theory can provide capacity as high as 3099 mA h g -1 by alloying with Li to form B 4 Li 5 . However, experimental studies of the boron anode have been rarely reported for room temperature lithium-ion batteries. Among the reported studies the electrochemical activity and cycling performance of the bulk crystalline boron anode material are poor at room temperature. In this work, we utilized an amorphous nanostructured one-dimensional (1D) boron material aiming at improving the electrochemical reactivity between boron and lithium ions at room temperature. The amorphous boron nanorod anode exhibited, at room temperature, a reversible capacity of 170 mA h g -1 at a current rate of 10 mA g -1 between 0.01 and 2 V. The anode also demonstrated good rate capability and cycling stability. The lithium storage mechanism was investigated by both sweep voltammetry measurements and galvanostatic intermittent titration techniques (GITTs). The sweep voltammetric analysis suggested that the contributions from lithium ion diffusion into boron and the capacitive process to the overall lithium charge storage are 57% and 43%, respectively. The results from GITT indicated that the discharge capacity at higher potentials (>∼0.2 V vs. Li/Li + ) could be ascribed to a capacitive process and at lower potentials (ions and the amorphous boron nanorod. This work provides new insights into designing nanostructured boron materials for lithium-ion batteries.

  18. Apparatus to measure emissivities of metallic films between 90K and room temperature

    International Nuclear Information System (INIS)

    Bekeris, V.I.; Ramos, E.D.; Sanchez, D.H.

    1975-01-01

    The development of multilayer insulations is aerospace and cryogenic required to know the emissivity of the metallic films used as reflective layers. This work describes an emissometer that measures the total hemispherical emissivity of metallic films evaporated on polyester substrates. The apparatus works at liquid oxigen temperatures and permits to get emissivities from 90K to room temperatures within a 15% precision. The emissometer construction and operation are described in detail. Results of measurements done on Single Aluminized Mylar are presented [pt

  19. Significant enhancement of room temperature ferromagnetism in surfactant coated polycrystalline Mn doped ZnO particles

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, O.D. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gopalakrishnan, I.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)]. E-mail: ikgopal@barc.gov.in; Sudakar, C. [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201 (United States); Kadam, R.M. [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kulshreshtha, S.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2007-07-12

    We report a surfactant assisted synthesis of Mn doped ZnO polycrystalline samples showing robust room temperature ferromagnetism as characterized by X-ray diffraction analysis, transmission electron microscopy, electron paramagnetic resonance and DC magnetization measurements. This surfactant assisted synthesis method, developed by us, is found to be highly reproducible. Further, it can also be extended to the synthesis of other transition metal doped ZnO.

  20. Single Photon, Spin, and Charge in Diamond Semiconductor at room temperature

    International Nuclear Information System (INIS)

    Yuki Doi

    2014-01-01

    The nitrogen-vacancy (NV) center in diamond is a promising candidate for a qubit driven at room temperature. In order to derive potential of NV center, manipulation of their charge state is a very important topic. Here we succeeded to electrically control between single NV-/NV0 by means of current injection. This method allows us to very stable charge state control. (author)

  1. Room-temperature electroluminescence of Er-doped hydrogenated amorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Gusev, Oleg; Bresler, Mikhail; Kuznetsov, Alexey; Kudoyarova, Vera; Pak, Petr; Terukov, Evgenii; Tsendin, Konstantin; Yassievich, Irina [A F Ioffe Physico-Technical Institute, Politekhnicheskaya 26, 194021 St. Petersburg (Russian Federation); Fuhs, Walther [Hahn-Meitner Institut, Abteilung Photovoltaik, Rudower Chaussee 5, D-12489 Berlin (Germany); Weiser, Gerhard [Phillips-Universitat Marburg, Fachbereich Physik, D-35032 Marburg (Germany)

    1998-05-11

    We have observed room-temperature erbium-ion electroluminescence in erbium-doped amorphous silicon. Electrical conduction through the structure is controlled by thermally activated ionization of deep D{sup -} defects in an electric field and the reverse process of capture of mobile electrons by D{sup 0} states. Defect-related Auger excitation (DRAE) is responsible for excitation of erbium ions located close to dangling-bond defects. Our experimental data are consistent with the mechanisms proposed

  2. Ultrasonic acoustic levitation for fast frame rate X-ray protein crystallography at room temperature

    OpenAIRE

    Soichiro Tsujino; Takashi Tomizaki

    2016-01-01

    Increasing the data acquisition rate of X-ray diffraction images for macromolecular crystals at room temperature at synchrotrons has the potential to significantly accelerate both structural analysis of biomolecules and structure-based drug developments. Using lysozyme model crystals, we demonstrated the rapid acquisition of X-ray diffraction datasets by combining a high frame rate pixel array detector with ultrasonic acoustic levitation of protein crystals in liquid droplets. The rapid spinn...

  3. Human preference and acceptance of increased air velocity to offset warm sensation at increased room temperatures

    OpenAIRE

    Cattarin, Giulio; Simone, Angela; Olesen, Bjarne W.

    2012-01-01

    Previous studies have demonstrated that in summertime increased air velocities can compensate for higher room temperatures to achieve comfortable conditions. In order to increase air movement, windows opening, ceiling or desk fans can be used at the expense of relatively low energy consumption. The present climatic chamber study examined energy performance and achievable thermal comfort of traditional and bladeless desk fans. Different effects of mechanical and simulated-natural airflow patte...

  4. Tribological reactions of perfluoroalkyl polyether oils with stainless steel under ultrahigh vacuum conditions at room temperature

    Science.gov (United States)

    Mori, Shigeyuki; Morales, Wilfredo

    1989-01-01

    The reaction between three types of commercial perfluoroalkyl polyether (PFPE) oils and stainless steel 440C was investigated experimentally during sliding under ultrahigh vacuum conditions at room temperature. It is found that the tribological reaction of PFPE is mainly affected by the activity of the mechanically formed fresh surfaces of metals rather than the heat generated at the sliding contacts. The fluorides formed on the wear track act as a boundary layer, reducing the friction coefficient.

  5. Nonlinear behavior of three-terminal graphene junctions at room temperature

    International Nuclear Information System (INIS)

    Kim, Wonjae; Riikonen, Juha; Lipsanen, Harri; Pasanen, Pirjo

    2012-01-01

    We demonstrate nonlinear behavior in three-terminal T-branch graphene devices at room temperature. A rectified nonlinear output at the center branch is observed when the device is biased by a push–pull configuration. Nonlinearity is assumed to arise from a difference in charge transfer through the metal–graphene contact barrier between two contacts. The sign of the rectification can be altered by changing the carrier type using the back-gate voltage. (paper)

  6. Complex hydrides as room-temperature solid electrolytes for rechargeable batteries

    DEFF Research Database (Denmark)

    Jongh, P. E. de; Blanchard, D.; Matsuo, M.

    2016-01-01

    A central goal in current battery research is to increase the safety and energy density of Li-ion batteries. Electrolytes nowadays typically consist of lithium salts dissolved in organic solvents. Solid electrolytes could facilitate safer batteries with higher capacities, as they are compatible...... electrolytes, discussing in detail LiBH4, strategies towards for fast room-temperature ionic conductors, alternative compounds, and first explorations of implementation of these electrolytes in all-solid-state batteries....

  7. TaS2 nanosheet-based room-temperature dosage meter for nitric oxide

    Directory of Open Access Journals (Sweden)

    Qiyuan He

    2014-09-01

    Full Text Available A miniature dosage meter for toxic gas is developed based on TaS2 nanosheets, which is capable of indicating the toxic dosage of trace level NO at room temperature. The TaS2 film-based chemiresistor shows an irreversible current response against the exposure of NO. The unique non-recovery characteristic makes the TaS2 film-based device an ideal indicator of total dosage of chronicle exposure.

  8. Composite properties for S-2 glass in a room-temperature-curable epoxy matrix

    Science.gov (United States)

    Clements, L. L.; Moore, R. L.

    1979-01-01

    The authors have measured thermal and mechanical properties of several composites of S-2 glass fiber in a room-temperature-curable epoxy matrix. The filament-wound composites ranged from 50 to 70 vol% fiber. The composites had generally good to excellent mechanical properties, particularly in view of the moderate cost of the material. However, the composites showed rapid increases in transverse thermal expansion above 50 C, and this property must be carefully considered if any use above that temperature is contemplated.

  9. Short communication: Stability and integrity of classical swine fever virus RNA stored at room temperature

    Directory of Open Access Journals (Sweden)

    Damarys Relova

    2017-12-01

    Full Text Available Worldwide cooperation between laboratories working with classical swine fever virus (CSFV requires exchange of virus isolates. For this purpose, shipment of CSFV RNA is a safe alternative to the exchange of infectious material. New techniques using desiccation have been developed to store RNA at room temperature and are reported as effective means of preserving RNA integrity. In this study, we evaluated the stability and integrity of dried CSFV RNA stored at room temperature. First, we determined the stability of CSFV RNA covering CSFV genome regions used typically for the detection of viral RNA in diagnostic samples by reverse transcription-polymerase chain reaction (RT-PCR. To this end, different concentrations of in vitro-transcribed RNAs of the 5’-untranslated region and of the NS5B gene were stored as dried RNA at 4, 20, and 37oC for two months. Aliquots were analyzed every week by CSFV-specific quantitative real-time RT-PCR. Neither the RNA concentration nor the storage temperature did affect CSFV RNA yields at any of the time evaluated until the end of the experiment. Furthermore, it was possible to recover infectious CSFV after transfection of SK-6 cells with dried viral RNA stored at room temperature for one week. The full-length E2 of CSFV was amplified from all the recovered viruses, and nucleotide sequence analysis revealed 100% identity with the corresponding sequence obtained from RNA of the original material. These results show that CSFV RNA stored as dried RNA at room temperature is stable, maintaining its integrity for downstream analyses and applications.

  10. Thermally-activated deformation in dispersion-hardened polycrystalline iron at room temperature

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Cotteril, P.

    1970-01-01

    The activation volume and dislocation velocity exponent have been obtained for polycrystalline iron in the extruded, extruded and annealed, and cold-rolled and annealed condition containing various amounts of alumina or zirconia particles, using the strain rate-change technique. It is found that ...... to the thermally activated flow stress contribution at room temperature. The dislocation velocity exponent also explains the yield-drop and Lüder's strain and is in a good agreement with Hahn's model....

  11. Investigation of Room Temperature Synthesis of Titanium Dioxide Nanoclusters Dispersed on Cubic MCM-48 Mesoporous Materials

    OpenAIRE

    Sridhar Budhi; Chia-Ming Wu; Dan Zhao; Ranjit T. Koodali

    2015-01-01

    Titania containing cubic MCM-48 mesoporous materials were synthesized successfully at room temperature by a modified Stöber method. The integrity of the cubic mesoporous phase was retained even at relatively high loadings of titania. The TiO2-MCM-48 materials were extensively characterized by a variety of physico-chemical techniques. The physico-chemical characterization indicate that Ti4+ ions can be substituted in framework tetrahedral positions. The relative amount of Ti4+ ions in tetrahe...

  12. Synthesis, characterization and magnetic properties of room-temperature nanofluid ferromagnetic graphite

    OpenAIRE

    Souza, N. S.; Sergeenkov, S.; Speglich, C.; Rivera, V. A. G.; Cardoso, C. A.; Pardo, H.; Mombru, A. W.; Rodrigues, A. D.; de Lima, O. F.; Araujo-Moreira, F. M.

    2009-01-01

    We report the chemical synthesis route, structural characterization, and physical properties of nanofluid magnetic graphite (NFMG) obtained from the previously synthesized bulk organic magnetic graphite (MG) by stabilizing the aqueous ferrofluid suspension with an addition of active cationic surfactant. The measured magnetization-field hysteresis curves along with the temperature dependence of magnetization confirmed room-temperature ferromagnetism in both MG and NFMG samples. (C) 2009 Americ...

  13. The synthesis of [2-13C]2-nitropropane at room temperature and at atmospheric pressure

    OpenAIRE

    Jacquemijns M; Zomer G

    1990-01-01

    In this report the synthesis of [2-13C]2-nitropropane at room temperature is described. [2-13C]Acetone was converted into the oxime with hydroxy hydrochloridelamine and sodium carbonate. Treatment with hypobromic acid resulted in 2-13C]2-bromo-2-nitropropane. Hydrogenation with sodium borohydride gave [2-13C]2-nitropropane in 14,3% overall yield.

  14. Materials for spintronic: Room temperature ferromagnetism in Zn-Mn-O interfaces

    International Nuclear Information System (INIS)

    Quesada, A.; Garcia, M.A.; Crespo, P.; Hernando, A.

    2006-01-01

    In this paper we study the room temperature ferromagnetism reported on Mn-doped ZnO and ascribed to spin polarization of conduction electrons. We experimentally show that the ferromagnetic behaviour is associated to the coexistence of Mn 3+ and Mn +4 in MnO 2 grains where diffusion of Zn promotes the Mn 4+→ Mn 3+ reduction. Potential uses of this material in spintronic devices are analysed

  15. One-step surface modification for irreversible bonding of various plastics with a poly(dimethylsiloxane) elastomer at room temperature.

    Science.gov (United States)

    Wu, Jing; Lee, Nae Yoon

    2014-05-07

    Here, we introduce a simple and facile method for bonding poly(dimethylsiloxane) (PDMS) to various plastics irreversibly via a one-step chemical treatment at room temperature. This was mediated by poly[dimethylsiloxane-co-(3-aminopropyl)methylsiloxane] (amine-PDMS linker), a chemical composed of a PDMS backbone incorporating an amine side group. Room temperature anchoring of the linker was achieved via a reaction between the amine functionality of the linker and the carbon backbone of the plastics, thereby producing urethane bonds. This resulted in the PDMS functionality being exposed on the plastic surface, mimicking the surface properties of bulk PDMS. Following corona treatment of the PDMS-modified plastic and a sheet of PDMS, the two surfaces were placed in contact with each other and heated at 80 °C for 1 h. This resulted in permanent bonding between PDMS and the plastic. To examine the effectiveness of the amine-PDMS linker coating procedure, the surfaces were characterized by measuring water contact angles and by employing X-ray photoelectron spectroscopy (XPS). Polycarbonate (PC), poly(ethylene terephthalate) (PET), poly(vinylchloride) (PVC), and polyimide (PI) were bonded successfully to PDMS using this method, with bond strengths of PC, PET, and PVC with PDMS measured to be approximately 428.5 ± 17.9, 361.7 ± 31.2, and 430.0 ± 14.9 kPa, respectively. The bond strength of a PC-PC homogeneous assembly, also realized using the proposed method, was measured to be approximately 343.9 ± 7.4 kPa. Delamination tests revealed that the PC-PC assembly was able to withstand intense introduction of a liquid whose per-minute injection volume was approximately 278 times greater than the total internal volume of the microchannel fabricated in PC. This demonstrated the robustness of the seal formed using the proposed technique.

  16. Fracture toughness of China low activation martensitic (CLAM) steel at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kunfeng [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Xu, Gang; Jiang, Siben [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2014-04-15

    Highlights: • The fracture toughness of CLAM steel at room temperature is 417.9 kJ/m{sup 2} measured by unloading compliance method according to the ASTM E1820-11. • The fracture toughness of CLAM steel at room temperature can be calculated on the basis of the fractal dimensions measured under plane strain conditions. The calculated result and relative error for this experiment are 454.6 kJ/m{sup 2} and 8.78% respectively. • The calculation method could be used to estimate the fracture toughness of materials with analysis of the fracture surface. - Abstract: The fracture toughness (J{sub IC}) of China low activation martensitic (CLAM) steel was tested at room temperature through the compact tension specimen, the result is 417.9 kJ/m{sup 2}, which is similar to the JLF-1 at same experimental conditions. The microstructural observation of the fracture surface shows that the fracture mode is a typical ductile fracture. Meanwhile, the fracture toughness is also calculated on the basis of the fractal dimension and the calculated result is 454.6 kJ/m{sup 2}, which is consistent well with the experimental result. This method could be used to estimate the fracture toughness of materials by analyzing of the fracture surface.

  17. Large low-field magnetoresistance of Fe3O4 nanocrystal at room temperature

    International Nuclear Information System (INIS)

    Mi, Shu; Liu, Rui; Li, Yuanyuan; Xie, Yong; Chen, Ziyu

    2017-01-01

    Superparamagnetic magnetite (Fe 3 O 4 ) nanoparticles with an average size of 6.5 nm and good monodispersion were synthesized and investigated by X-ray diffraction, Raman spectrometer, transmission electron microscopy and vibrating sample magnetometer. Corresponding low-field magnetoresistance (LFMR) was tested by physical property measurement system. A quite high LFMR has been observed at room temperature. For examples, at a field of 3000 Oe, the LFMR is −3.5%, and when the field increases to 6000 Oe, the LFMR is up to −5.1%. The electron spin polarization was estimated at 25%. This result is superior to the previous reports showing the LFMR of no more than 2% at room temperature. The conduction mechanism is proposed to be the tunneling of conduction electrons between adjacent grains considering that the monodisperse nanocrystals may supply more grain boundaries increasing the tunneling probability, and consequently enhancing the overall magnetoresistance. - Highlights: • Superparamagnetic Fe3O4 nanoparticles with small size were synthesized. • A quite high LFMR has been observed at room temperature. • The more grain boundaries increase the tunneling probability and enlarge the MR. • The fast response of the sample increase the MR at a low field.

  18. Room temperature NO2-sensing properties of porous silicon/tungsten oxide nanorods composite

    International Nuclear Information System (INIS)

    Wei, Yulong; Hu, Ming; Wang, Dengfeng; Zhang, Weiyi; Qin, Yuxiang

    2015-01-01

    Highlights: • Porous silicon/WO 3 nanorods composite is synthesized via hydrothermal method. • The morphology of WO 3 nanorods depends on the amount of oxalic acid (pH value). • The sensor can detect ppb level NO 2 at room temperature. - Abstract: One-dimensional single crystalline WO 3 nanorods have been successfully synthesized onto the porous silicon substrates by a seed-induced hydrothermal method. The controlled morphology of porous silicon/tungsten oxide nanorods composite was obtained by using oxalic acid as an organic inducer. The reaction was carried out at 180 °C for 2 h. The influence of oxalic acid (pH value) on the morphology of porous silicon/tungsten oxide nanorods composite was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The NO 2 -sensing properties of the sensor based on porous silicon/tungsten oxide nanorods composite were investigated at different temperatures ranging from room temperature (∼25 °C) to 300 °C. At room temperature, the sensor behaved as a typical p-type semiconductor and exhibited high gas response, good repeatability and excellent selectivity characteristics toward NO 2 gas due to its high specific surface area, special structure, and large amounts of oxygen vacancies

  19. Room Temperature Monoclinic Phase in BaTiO3 Single Crystals

    Science.gov (United States)

    Denev, Sava; Kumar, Amit; Barnes, Andrew; Vlahos, Eftihia; Shepard, Gabriella; Gopalan, Venkatraman

    2010-03-01

    BaTiO3 is a well studied ferroelectric material for the last half century. It is well known to show phase transitions to tetragonal, orthorhombic and rhombohedral phases upon cooling. Yet, some old and some recent studies have argued that all these phases co-exist with a second phase with monoclinic distortion. Using optical second harmonic generation (SHG) at room temperature we directly present evidence for such monoclininc phase co-existing with tetragonal phase at room temperature. We observe domains with the expected tetragonal symmetry exhibiting 90^o and 180^o domain walls. However, at points of higher stress at the tips of the interpenetrating tetragonal domains we observe a well pronounced metastable ``staircase pattern'' with a micron-scale fine structure. Polarization studies show that this phase can be explained only by monoclinic symmetry. This phase is very sensitive to external perturbations such as temperature and fields, hence stabilizing this phase at room temperature could lead to large properties' tunability.

  20. Microbiological viability of bovine amniotic membrane stored in glycerin 99% at room temperature for 48 months

    Directory of Open Access Journals (Sweden)

    Kelly Cristine de Sousa Pontes

    Full Text Available ABSTRACT The medium for storing biological tissues is of great importance for their optimal use in surgery. Glycerin has been proven efficient for storing diverse tissues for prolonged time, but the preservation of the bovine amniotic membrane in glycerin 99% at room temperature has never been evaluated to be used safely in surgical procedures. This study evaluated the preservation of 80 bovine amniotic membrane samples stored in glycerin 99% at room temperature. The samples were randomly divided evenly into four groups. Samples were microbiologically tested after 1, 6, 12 and 48 months of storage. The presence of bacteria and fungi in the samples was evaluated by inoculation on blood agar and incubation at 37 ºC for 48 hours and on Sabouraud agar at 25 ºC for 5 to 10 days. No fungal or bacterial growth was detected in any of the samples. It was concluded that glycerin is an efficient medium, regarding microbiology, for preserving pre-prepared bovine amniotic membrane, keeping the tissue free of microorganisms that grow in the media up to 48 months at room temperature.

  1. Above room temperature ferromagnetism in Si:Mn and TiO(2-delta)Co.

    Science.gov (United States)

    Granovsky, A; Orlov, A; Perov, N; Gan'shina, E; Semisalova, A; Balagurov, L; Kulemanov, I; Sapelkin, A; Rogalev, A; Smekhova, A

    2012-09-01

    We present recent experimental results on the structural, electrical, magnetic, and magneto-optical properties of Mn-implanted Si and Co-doped TiO(2-delta) magnetic oxides. Si wafers, both n- and p-type, with high and low resistivity, were used as the starting materials for implantation with Mn ions at the fluencies up to 5 x 10(16) cm(-2). The saturation magnetization was found to show the lack of any regular dependence on the Si conductivity type, type of impurity and the short post-implantation annealing. According to XMCD Mn impurity in Si does not bear any appreciable magnetic moment at room temperature. The obtained results indicate that above room temperature ferromagnetism in Mn-implanted Si originates not from Mn impurity but rather from structural defects in Si. The TiO(2-delta):Co thin films were deposited on LaAlO3 (001) substrates by magnetron sputtering in the argon-oxygen atmosphere at oxygen partial pressure of 2 x 10(-6)-2 x 10(-4) Torr. The obtained transverse Kerr effect spectra at the visible and XMCD spectra indicate on intrinsic room temperature ferromagnetism in TiO(2-delta):Co thin films at low (< 1%) volume fraction of Co.

  2. High performance hydrogen storage from Be-BTB metal-organic framework at room temperature.

    Science.gov (United States)

    Lim, Wei-Xian; Thornton, Aaron W; Hill, Anita J; Cox, Barry J; Hill, James M; Hill, Matthew R

    2013-07-09

    The metal-organic framework beryllium benzene tribenzoate (Be-BTB) has recently been reported to have one of the highest gravimetric hydrogen uptakes at room temperature. Storage at room temperature is one of the key requirements for the practical viability of hydrogen-powered vehicles. Be-BTB has an exceptional 298 K storage capacity of 2.3 wt % hydrogen. This result is surprising given that the low adsorption enthalpy of 5.5 kJ mol(-1). In this work, a combination of atomistic simulation and continuum modeling reveals that the beryllium rings contribute strongly to the hydrogen interaction with the framework. These simulations are extended with a thermodynamic energy optimization (TEO) model to compare the performance of Be-BTB to a compressed H2 tank and benchmark materials MOF-5 and MOF-177 in a MOF-based fuel cell. Our investigation shows that none of the MOF-filled tanks satisfy the United States Department of Energy (DOE) storage targets within the required operating temperatures and pressures. However, the Be-BTB tank delivers the most energy per volume and mass compared to the other material-based storage tanks. The pore size and the framework mass are shown to be contributing factors responsible for the superior room temperature hydrogen adsorption of Be-BTB.

  3. Room temperature ferromagnetism of tin oxide nanocrystal based on synthesis methods

    Energy Technology Data Exchange (ETDEWEB)

    Sakthiraj, K.; Hema, M. [Department of Physics, Kamaraj College of Engineering and Technology, Virudhunagar 626001, Tamil Nadu (India); Balachandrakumar, K. [Department of Physics, Raja Doraisingam Government Arts College, Sivagangai 630561, Tamil Nadu (India)

    2016-04-15

    The experimental conditions used in the preparation of nanocrystalline oxide materials play an important role in the room temperature ferromagnetism of the product. In the present work, a comparison was made between sol–gel, microwave assisted sol–gel and hydrothermal methods for preparing tin oxide nanocrystal. X-ray diffraction analysis indicates the formation of tetragonal rutile phase structure for all the samples. The crystallite size was estimated from the HRTEM images and it is around 6–12 nm. Using optical absorbance measurement, the band gap energy value of the samples has been calculated. It reveals the existence of quantum confinement effect in all the prepared samples. Photoluminescence (PL) spectra confirms that the luminescence process originates from the structural defects such as oxygen vacancies present in the samples. Room temperature hysteresis loop was clearly observed in M–H curve of all the samples. But the sol–gel derived sample shows the higher values of saturation magnetization (M{sub s}) and remanence (M{sub r}) than other two samples. This study reveals that the sol–gel method is superior to the other two methods for producing room temperature ferromagnetism in tin oxide nanocrystal.

  4. Room temperature Cu-Cu direct bonding using surface activated bonding method

    International Nuclear Information System (INIS)

    Kim, T.H.; Howlader, M.M.R.; Itoh, T.; Suga, T.

    2003-01-01

    Thin copper (Cu) films of 80 nm thickness deposited on a diffusion barrier layered 8 in. silicon wafers were directly bonded at room temperature using the surface activated bonding method. A low energy Ar ion beam of 40-100 eV was used to activate the Cu surface prior to bonding. Contacting two surface-activated wafers enables successful Cu-Cu direct bonding. The bonding process was carried out under an ultrahigh vacuum condition. No thermal annealing was required to increase the bonding strength since the bonded interface was strong enough at room temperature. The chemical constitution of the Cu surface was examined by Auger electron spectroscope. It was observed that carbon-based contaminations and native oxides on copper surface were effectively removed by Ar ion beam irradiation for 60 s without any wet cleaning processes. An atomic force microscope study shows that the Ar ion beam process causes no surface roughness degradation. Tensile test results show that high bonding strength equivalent to bulk material is achieved at room temperature. The cross-sectional transmission electron microscope observations reveal the presence of void-free bonding interface without intermediate layer at the bonded Cu surfaces

  5. Response of a Zn2TiO4 Gas Sensor to Propanol at Room Temperature

    Directory of Open Access Journals (Sweden)

    Ibrahim Gaidan

    2017-08-01

    Full Text Available In this study, three different compositions of ZnO and TiO2 powders were cold compressed and then heated at 1250 °C for five hours. The samples were ground to powder form. The powders were mixed with 5 wt % of polyvinyl butyral (PVB as binder and 1.5 wt % carbon black and ethylene-glyco-lmono-butyl-ether as a solvent to form screen-printed pastes. The prepared pastes were screen printed on the top of alumina substrates containing arrays of three copper electrodes. The three fabricated sensors were tested to detect propanol at room temperature at two different concentration ranges. The first concentration range was from 500 to 3000 ppm while the second concentration range was from 2500 to 5000 ppm, with testing taking place in steps of 500 ppm. The response of the sensors was found to increase monotonically in response to the increment in the propanol concentration. The surface morphology and chemical composition of the prepared samples were characterized by Scanning Electron Microscopy (SEM and X-Ray Diffraction (XRD. The sensors displayed good sensitivity to propanol vapors at room temperature. Operation under room-temperature conditions make these sensors novel, as other metal oxide sensors operate only at high temperature.

  6. FAST TRACK COMMUNICATION: Reproducible room temperature giant magnetocaloric effect in Fe-Rh

    Science.gov (United States)

    Manekar, Meghmalhar; Roy, S. B.

    2008-10-01

    We present the results of magnetocaloric effect (MCE) studies in polycrystalline Fe-Rh alloy over a temperature range of 250-345 K across the first order antiferromagnetic to ferromagnetic transition. By measuring the MCE under various thermomagnetic histories, contrary to the long held belief, we show here explicitly that the giant MCE in Fe-Rh near room temperature does not vanish after the first field cycle. In spite of the fact that the virgin magnetization curve is lost after the first field cycle near room temperature, reproducibility in the MCE under multiple field cycles can be achieved by properly choosing a combination of isothermal and adiabatic field variation cycles in the field-temperature phase space. This reproducible MCE leads to a large effective refrigerant capacity of 324.42 J kg-1, which is larger than that of the well-known magnetocaloric material Gd5Si2Ge2. This information could be important as Fe-Rh has the advantage of having a working temperature of around 300 K, which can be used for room temperature magnetic refrigeration.

  7. Influence of pre-measurement thermal treatment on OSL of synthetic quartz measured at room temperature

    International Nuclear Information System (INIS)

    Kale, Y.D.; Gandhi, Y.H.

    2008-01-01

    Much effort has been made to study the influence of pre-measurement thermal treatment and ionizing radiation on quartz specimens owing to its use in a large number of applications. Optically stimulated luminescence (OSL) being a structured and sensitive phenomenon promises to correlate the responsible color center and luminescence emission. OSL studies on quartz with such conditions can reveal many significant results. The aim of the present investigation is to understand the effect of annealing temperature on OSL characteristics of synthetic quartz recorded at room temperature. At identical annealing duration and β-dose, the shape of OSL decay curve remains non-exponential; when specimens annealed at lower temperature (∼400 deg. C). The shape of decay curve changes to exponential in nature along with rise in OSL intensity when the specimen was given higher temperature of annealing (>400 deg. C). The effects of such protocol on pattern of OSL sensitivity as well as area under the OSL decay curve are also presented here. The presence of shallow traps, when OSL decay curve was recorded at room temperature seems to be responsible for the changes in OSL pattern. The influence of shallow traps is attributed to non-exponential decay of OSL recorded at room temperature

  8. Room temperature chemical synthesis of Cu(OH){sub 2} thin films for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Gurav, K.V. [Thin Film Photonic and Electronics Lab, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Puk-Gu, Gwangju 500-757 (Korea, Republic of); Patil, U.M. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416 007 (M.S.) (India); Shin, S.W.; Agawane, G.L.; Suryawanshi, M.P.; Pawar, S.M.; Patil, P.S. [Thin Film Photonic and Electronics Lab, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Puk-Gu, Gwangju 500-757 (Korea, Republic of); Lokhande, C.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416 007 (M.S.) (India); Kim, J.H., E-mail: jinhyeok@chonnam.ac.kr [Thin Film Photonic and Electronics Lab, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-dong, Puk-Gu, Gwangju 500-757 (Korea, Republic of)

    2013-10-05

    Highlights: •Cu(OH){sub 2} is presented as the new supercapacitive material. •The novel room temperature method used for the synthesis of Cu(OH){sub 2}. •The hydrous, nanograined Cu(OH){sub 2} shows higher specific capacitance of 120 F/g. -- Abstract: Room temperature soft chemical synthesis route is used to grow nanograined copper hydroxide [Cu(OH){sub 2}] thin films on glass and stainless steel substrates. The structural, morphological, optical and wettability properties of Cu(OH){sub 2} thin films are studied by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), UV–vis spectrophotometer and water contact angle measurement techniques. The results showed that, room temperature chemical synthesis route allows to form the nanograined and hydrophilic Cu(OH){sub 2} thin films with optical band gap energy of 3.0 eV. The electrochemical properties of Cu(OH){sub 2} thin films are studied in an aqueous 1 M NaOH electrolyte using cyclic voltammetry. The sample exhibited supercapacitive behavior with 120 F/g specific capacitance.

  9. Room temperature chemical synthesis of Cu(OH)2 thin films for supercapacitor application

    International Nuclear Information System (INIS)

    Gurav, K.V.; Patil, U.M.; Shin, S.W.; Agawane, G.L.; Suryawanshi, M.P.; Pawar, S.M.; Patil, P.S.; Lokhande, C.D.; Kim, J.H.

    2013-01-01

    Highlights: •Cu(OH) 2 is presented as the new supercapacitive material. •The novel room temperature method used for the synthesis of Cu(OH) 2 . •The hydrous, nanograined Cu(OH) 2 shows higher specific capacitance of 120 F/g. -- Abstract: Room temperature soft chemical synthesis route is used to grow nanograined copper hydroxide [Cu(OH) 2 ] thin films on glass and stainless steel substrates. The structural, morphological, optical and wettability properties of Cu(OH) 2 thin films are studied by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), UV–vis spectrophotometer and water contact angle measurement techniques. The results showed that, room temperature chemical synthesis route allows to form the nanograined and hydrophilic Cu(OH) 2 thin films with optical band gap energy of 3.0 eV. The electrochemical properties of Cu(OH) 2 thin films are studied in an aqueous 1 M NaOH electrolyte using cyclic voltammetry. The sample exhibited supercapacitive behavior with 120 F/g specific capacitance

  10. Room temperature ferromagnetism in Co doped ZnO within an optimal doping level of 5%

    International Nuclear Information System (INIS)

    Mohapatra, J.; Mishra, D.K.; Mishra, Debabrata; Perumal, A.; Medicherla, V.R.R.; Phase, D.M.; Singh, S.K.

    2012-01-01

    Highlights: ► Zn 1−x Co x O ((0 ≤ x ≤ 0.1)) system synthesized by solid state reaction technique. ► Observation of room temperature ferromagnetism for 3 and 5% Co doped ZnO. ► XPS and EPMA studies predict the occurrence of segregated CoO clusters. ► Suppresses ferromagnetic ordering in higher doping percentage of Co (>5%). -- Abstract: We report on the structural, micro-structural and magnetic properties of Zn 1−x Co x O (0 ≤ x ≤ 0.1) system. Electron probe micro-structural analysis on 5% Co doped ZnO indicates the presence of segregated cobalt oxide which is also confirmed from the Co 2p core level X-ray photoelectron spectrum. The presence of oxygen defects in lower percentage of Co doped ZnO (≤5%) enhances the carrier mediated exchange interaction and thereby enhancing the room-temperature ferromagnetic behaviour. Higher doping percentage of cobalt (>5%) creates weak link between the grains and suppresses the carrier mediated exchange interaction. This is the reason why room temperature ferromagnetism is not observed in 7% and 10% Co doped ZnO.

  11. Effect of room temperature prestrain on creep life of austenitic 25Cr-20Ni stainless steels

    International Nuclear Information System (INIS)

    Park, In Duck; Ahn, Seok Hwan; Nam, Ki Woo

    2004-01-01

    25Cr-20Ni series strainless steels have an excellent high temperature strength, high oxidation and high corrosion resistance. However, further improvement can be expected of creep strength by work hardening prior creep. In the present study, the effect of prestraining at room temperature on the creep behavior of a Class M(STS310S) and a Class A(STS310J1TB) alloy containing precipitates have been examined. Prestraining was carried out at room temperature and range of prestrain was 0.5∼2.5 % at STS310J1TB and 2.0∼7.0 % at STS310S. Creep behavior and creep rate of pre-strained specimens were compared with that of virgin specimens. Room temperature prestraining produced the creep life that is longer than that of a virgin specimen both for STS310J1TB and STS310S when creep test was carried out at the temperature lower than recrystallization temperature. The reason for this improvement of creep life was ascribable to the interaction between dislocations and precipitates in addition to the dislocation-dislocation interaction in STS310J1TB and the dislocation-dislocation interaction in STS310S. The beneficial effect of prestraining in STS310J1TB was larger than that of STS310S

  12. Room temperature synthesis of 2D CuO nanoleaves in aqueous solution

    International Nuclear Information System (INIS)

    Zhao Yan; Li Yunling; Wang Zichen; Zhao Jingzhe; Ma Dechong; Hou Shengnan; Li Linzhi; Hao Xinli

    2011-01-01

    A simple room temperature method was reported for the synthesis of CuO nanocrystals in aqueous solution through the sequence of Cu 2+ → Cu(OA) 2 → Cu(OH) 2 → Cu(OH) 4 2- → CuO. Sodium oleate (SOA) was used as the surfactant and shape controller. The as-prepared samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectroscopy (UV-vis) and differential thermal analysis (DTA). It can be seen that 1D Cu(OH) 2 nanowires were first obtained from Cu(OA) 2 and, at room temperature, converted into 2D CuO nanoleaves (CuO NLs) in a short time under a weakly basic environment. On prolonging the reaction time, the top part of these 2D nanoleaves branched and separated along the long axis to form 1D rod-like nano-CuO because of the assistance of SOA. A possible transformation mechanism of Cu(OH) 2 to CuO nanostructures at room temperature in aqueous solution is discussed. The transformation velocity can be controlled by changing the pH value of the system. The prepared CuO NLs were used to construct an enzyme-free glucose sensor. The detecting results showed that the designed sensor exhibited good amperometric responses towards glucose with good anti-interferent ability.

  13. Prediction of the equilibrium structures and photomagnetic properties of the Prussian blue analogue RbMn[Fe(CN)(6)] by density functional theory

    NARCIS (Netherlands)

    Luzon, Javier; Castro, Miguel; Vertelman, Esther J.M.; Gengler, Régis Y.N.; van Koningsbruggen, Petra J.; Molodtsova, Olga; Knupfer, Martin; Rudolf, Petra; Loosdrecht, Paul H.M. van; Broer, Ria

    2008-01-01

    A periodic density functional theory method using the B3LYP hybrid exchange-correlation potential is applied to the Prussian blue analogue RbMn[Fe(CN)(6)] to evaluate the suitability of the method for studying, and predicting, the photomagnetic behavior of Prussian blue analogues and related

  14. Comparison between Silicon-Carbide and diamond for fast neutron detection at room temperature

    Directory of Open Access Journals (Sweden)

    Obraztsova O.

    2018-01-01

    diamond detectors irradiated with 14 MeV neutrons at room temperature.

  15. Comparison between Silicon-Carbide and diamond for fast neutron detection at room temperature

    Science.gov (United States)

    Obraztsova, O.; Ottaviani, L.; Klix, A.; Döring, T.; Palais, O.; Lyoussi, A.

    2018-01-01

    detectors irradiated with 14 MeV neutrons at room temperature.

  16. Structure-function correlation of chloroquine and analogues as transgene expression enhancers in nonviral gene delivery.

    Science.gov (United States)

    Cheng, Jianjun; Zeidan, Ryan; Mishra, Swaroop; Liu, Aijie; Pun, Suzie H; Kulkarni, Rajan P; Jensen, Gregory S; Bellocq, Nathalie C; Davis, Mark E

    2006-11-02

    To understand how chloroquine (CQ) enhances transgene expression in polycation-based, nonviral gene delivery systems, a number of CQ analogues with variations in the aliphatic amino side chain or in the aromatic ring are synthesized and investigated. Our studies indicate that the aliphatic amino moiety of CQ is essential to provide increased gene expression. Further, the enhancements are more dramatically affected by changes to the aromatic ring and are positively correlated to the strength of intercalation between DNA and the CQ analogues. Quinacrine (QC), a CQ analogue with a fused acridinyl structure that can strongly intercalate DNA, enhances transfection similarly to CQ at a concentration 10 times lower, while N(4)-(4-pyridinyl)-N(1),N(1)-diethyl-1,4-pentanediamine (CP), a CQ analogue that has a weakly intercalating pyridinyl ring, shows no effect on gene expression. Subtle change on the 7-substituent of the chloroquine aromatic structure can also greatly affect the ability of the CQ analogues to enhance transgene expression. Transfection in the presence of N(4)-(7-trifluoromethyl-4-quinolinyl)-N(1),N(1)-diethyl-1,4-pentanediamin e (CQ7a) shows expression efficiency 10 times higher than in the presence of CQ at same concentration, while transfection in the presence of N(4)-(4-quinolinyl)-N(1),N(1)-diethyl-1,4-pentanediamine (CQ7b) does not reveal any enhancing effects on expression. Through a number of comparative studies with CQ and its analogues, we conclude that there are at least three mechanistic features of CQ that lead to the enhancement in gene expression: (i) pH buffering in endocytic vesicles, (ii) displacement of polycations from the nucleic acids in polyplexes, and (iii) alteration of the biophysical properties of the released nucleic acid.

  17. Spin relaxation dynamics of holes in intrinsic GaAs quantum wells studied by transient circular dichromatic absorption spectroscopy at room temperature.

    Science.gov (United States)

    Fang, Shaoyin; Zhu, Ruidan; Lai, Tianshu

    2017-03-21

    Spin relaxation dynamics of holes in intrinsic GaAs quantum wells is studied using time-resolved circular dichromatic absorption spectroscopy at room temperature. It is found that ultrafast dynamics is dominated by the cooperative contributions of band filling and many-body effects. The relative contribution of the two effects is opposite in strength for electrons and holes. As a result, transient circular dichromatic differential transmission (TCD-DT) with co- and cross-circularly polarized pump and probe presents different strength at several picosecond delay time. Ultrafast spin relaxation dynamics of excited holes is sensitively reflected in TCD-DT with cross-circularly polarized pump and probe. A model, including coherent artifact, thermalization of nonthermal carriers and the cooperative contribution of band filling and many-body effects, is developed, and used to fit TCD-DT with cross-circularly polarized pump and probe. Spin relaxation time of holes is achieved as a function of excited hole density for the first time at room temperature, and increases with hole density, which disagrees with a theoretical prediction based on EY spin relaxation mechanism, implying that EY mechanism may be not dominant hole spin relaxation mechanism at room temperature, but DP mechanism is dominant possibly.

  18. Liquid–liquid extraction of Pu(IV), U(VI) and Am(III) using malonamide in room temperature ionic liquid as diluent

    International Nuclear Information System (INIS)

    Rout, Alok; Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2012-01-01

    Highlights: ► Extraction of actinides using malonamide in room temperature ionic liquid. ► High distribution ratios of actinides in room temperature ionic liquid. ► Ion exchange mechanism. ► Stoichiometry of extraction. ► High separation factors of U(VI) and Pu(IV) over Am(III) and fission products. - Abstract: The extraction behavior of U(VI), Pu(IV) and Am(III) from nitric acid medium by a solution of N,N-dimethyl-N,N-dioctyl-2-(2-hexyloxyethyl)malonamide (DMDOHEMA) in the room temperature ionic liquid, 1–butyl–3–methylimidazolium bis(trifluoromethanesulfonyl)imide (C 4 mimNTf 2 ), was studied. The distribution ratio of these actinides in DMDOHEMA/C 4 mimNTf 2 was measured as a function of various parameters such as the concentration of nitric acid, DMDOHEMA, NTf 2 − , alkyl chain length of ionic liquid. The extraction of actinides in the absence of DMDOHEMA was insignificant and the distribution ratio achieved in conjunction with C 4 mimNTf 2 , was remarkable. The separation factor of U(VI) and Pu(IV) achieved with the use of DMDOHEMA, ionic liquid was compared with Am(III) and other fission products. The stoichiometry of the metal-solvate was determined to be 1:2 for U(VI) and Pu(IV) and 1:3 for Am(III).

  19. Magnetic properties of nanocrystalline CoFe{sub 2}O{sub 4} powders prepared at room temperature: variation with crystallite size

    Energy Technology Data Exchange (ETDEWEB)

    Rajendran, M.; Pullar, R.C.; Bhattacharya, A.K. E-mail: ashokbhattacharya@warwick.ac.uk; Das, D.; Chintalapudi, S.N.; Majumdar, C.K

    2001-06-01

    The magnetic properties of nanocrystalline CoFe{sub 2}O{sub 4} powders prepared by a redox process at room temperature have been studied by vibrating sample magnetometer (VSM). The average crystallite size of the powders varied from 6 to 20 nm by changing the synthesis conditions and the corresponding saturation magnetisation (M{sub s}) value ranged from 9 to 38 emu g{sup -1}. On heating, the crystallite size increased with corresponding increase in M{sub s} values. At 1073 K all samples achieved M{sub s} values close to 73 emu g{sup -1}. On increasing the crystallite size, the coercivity (H{sub c}) increased passed through a maximum and dropped. Cobalt ferrite powder with an average crystallite size of 6 nm prepared at room temperature achieved desirable values of M{sub s}=60 emu g{sup -1} and H{sub c}=1.42 kOe after thermal annealing at 973 K. The Moessbauer spectra were recorded for CoFe{sub 2}O{sub 4} having a range of crystallite sizes at room temperature and at low temperatures down to 40 K. The magnetic and Moessbauer results are provided for nanocrystalline CoFe{sub 2}O{sub 4} as a function of crystallite size and measurement temperature.

  20. Changes in renal function after discontinuation of vitamin D analogues in advanced chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Francisco Caravaca

    2018-03-01

    Full Text Available Background: In routine clinical practice, the prescription of vitamin D analogues (VDA in patients with chronic kidney disease (CKD is often associated with a decline of the estimated renal function. The reason for this is not fully understood. Aims: To analyze the effects of VDA discontinuation in advanced CKD and to determine the factors associated with changes in renal function. Material and methods: Retrospective cohort study of adult patients with advanced CKD. The case subgroup was treated with VDA and this medication was discontinued at baseline (the first visit. The control subgroup was not treated with VDA and they were selected according to comparability principles for CKD progression by propensity score matching. The primary outcome measure was a change to both the estimated glomerular filtration rate (MDRD-GFR and the measured glomerular filtration rate (mGFR by combined creatinine and urea clearances. Baseline parameters related to mineral metabolism and creatinine generation were analyzed as potential determinants of renal function changes. Results: The study sample consisted of 67 cases and 67 controls. Renal function improved in 67% of cases and worsened in 72% of controls (p < 0.0001. Changes in MDRD-GFR for the case subgroup and the control subgroup were +0.455 ± 0.997 vs. −0.436 ± 1.103 ml/min/1.73 m2/month (p < 0.0001, respectively. Total creatinine excretion was slightly higher in cases than in controls but the difference was not significant.According to multivariate logistic and linear regression analyses, baseline total serum calcium was one of the best determinants of both renal function recovery (Odds ratio = 3.49; p = 0.001, and of the extent of renal function recovery (beta = 0.276; p = 0.001. Conclusions: Discontinuation of VDA treatment in CKD patients is associated with significant recovery of estimated renal function. The extent of these changes is

  1. Synthesis, characterization and performance of zinc ferrite nanorods for room temperature sensing applications

    International Nuclear Information System (INIS)

    Singh, Archana; Singh, Ajendra; Singh, Satyendra; Tandon, Poonam; Yadav, B.C.; Yadav, R.R.

    2015-01-01

    Highlights: • Fabrication of zinc ferrite thin film LPG and CO 2 gas sensors. • Morphological growth of nanorods. • Significant advancement towards the fabrication of a reliable LPG sensor. • A new pathway to produce nanorods as sensorial material. - Abstract: In the present communication, nanorods of zinc ferrite was synthesized and fabricated by employing sol–gel spin coating process. The synthesized material was characterized using X-ray diffraction, scanning electron microscopy, acoustic particle sizer, atomic force microscopy, UV–visible absorption and infrared spectroscopic techniques. Thermal properties were investigated using differential scanning calorimetry. The XRD reveals cubic spinel structure with minimum crystallite size 10 nm. SEM image of the film shows porous surface morphology with uniform distribution of nanorods. The band gap of the zinc ferrite nanorods was found 3.80 eV using the Tauc plot. ZnFe 2 O 4 shows weak super paramagnetic behavior at room temperature investigated using the vibrating sample magnetometer. Further, the liquefied petroleum gas (LPG) and carbon dioxide gas (CO 2 ) sensing properties of the fabricated film were investigated at room temperature (25 °C). More variations in electrical resistance were observed for LPG in comparison to CO 2 gas. The parameters such as lattice constant, X-ray density, porosity and specific surface area were also calculated for the better understanding of the observed gas sensing properties. High sensitivity and percentage sensor response, small response and recovery times, good reproducibility and stability characterized the fabricated sensor for the detection of LPG at room temperature

  2. Ripening and shelf life of 'BRS Caipira' banana fruit stored under room temperature or refrigeration

    Directory of Open Access Journals (Sweden)

    Orjana Santos Lima

    2014-04-01

    Full Text Available BRS Caipira variety, internationally known as 'Yangambi km 5', is an alternative to meet the demand of 'Maçã'-type fruit due to its resistance to Panama disease. This study had the objective of generating information about 'BRS Caipira' fruit ripening and cold storage potential. For the ripening study fruits were stored under room temperature conditions (25±2°C / 58±6% U.R. and assessed for postharvest life evaluation and characterization of seven maturity stages based on peel color: completely green - MS1; green with yellow traces - MS2; more green than yellow - MS3; more yellow than green - MS4; yellow with green tips - MS5; completely yellow - MS6; yellow with brown spots - MS7. For the cold storage potential study, fruits at MS1 were cold stored (14±1°C / 53±2% U.R. for 28 days. Weekly, fruits were transferred to room temperature to ripen until MS6 when were assessed for quality attributes. Ripening of 'BRS Caipira' fruit was characterized as slow between MS1 and MS2 (averaging five days, then fast between MS2 and MS6 (up to four days in average, and undergoing determinant changes between MS6 and MS7: pulp yield reached 80%, titratable acidity reduced by 50% and ratio increased by 78%. Cold storage extended shelf life by up to 19 days as compared with control, without visible symptoms of chilling injury, although tends to reduce soluble solids in ripe fruit. Maximum recommended time for storage of 'BRS Caipira' fruit at 14°C is 21 days, since it allows a few more days under room temperature until fruit reach MS6.

  3. Room Temperature Stable PspA-Based Nanovaccine Induces Protective Immunity

    Directory of Open Access Journals (Sweden)

    Danielle A. Wagner-Muñiz

    2018-03-01

    Full Text Available Streptococcus pneumoniae is a major causative agent of pneumonia, a debilitating disease particularly in young and elderly populations, and is the leading worldwide cause of death in children under the age of five. While there are existing vaccines against S. pneumoniae, none are protective across all serotypes. Pneumococcal surface protein A (PspA, a key virulence factor of S. pneumoniae, is an antigen that may be incorporated into future vaccines to address the immunological challenges presented by the diversity of capsular antigens. PspA has been shown to be immunogenic and capable of initiating a humoral immune response that is reactive across approximately 94% of pneumococcal strains. Biodegradable polyanhydrides have been studied as a nanoparticle-based vaccine (i.e., nanovaccine platform to stabilize labile proteins, to provide adjuvanticity, and enhance patient compliance by providing protective immunity in a single dose. In this study, we designed a room temperature stable PspA-based polyanhydride nanovaccine that eliminated the need for a free protein component (i.e., 100% encapsulated within the nanoparticles. Mice were immunized once with the lead nanovaccine and upon challenge, presented significantly higher survival rates than animals immunized with soluble protein alone, even with a 25-fold reduction in protein dose. This lead nanovaccine formulation performed similarly to protein adjuvanted with Alum, however, with much less tissue reactogenicity at the site of immunization. By eliminating the free PspA from the nanovaccine formulation, the lead nanovaccine was efficacious after being stored dry for 60 days at room temperature, breaking the need for maintaining the cold chain. Altogether, this study demonstrated that a single dose PspA-based nanovaccine against S. pneumoniae induced protective immunity and provided thermal stability when stored at room temperature for at least 60 days.

  4. Room temperature ferromagnetism in Mn-doped NiO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Layek, Samar, E-mail: samarlayek@gmail.com; Verma, H.C.

    2016-01-01

    Mn-doped NiO nanoparticles of the series Ni{sub 1−x}Mn{sub x}O (x=0.00, 0.02, 0.04 and 0.06) are successfully synthesized using a low temperature hydrothermal method. Samples up to 6% Mn-doping are single phase in nature as observed from powder x-ray diffraction (XRD) studies. Rietveld refinement of the XRD data shows that all the single phase samples crystallize in the NaCl like fcc structure with space group Fm-3m. Unit cell volume decreases with increasing Mn-doping. Pure NiO nanoparticles show weak ferromagnetism, may be due to nanosize nature. Introduction of Mn within NiO lattice improves the magnetic properties significantly. Room temperature ferromagnetism is found in all the doped samples whereas the magnetization is highest for 2% Mn-doping and then decreases with further doping. The ZFC and FC branches in the temperature dependent magnetization separate well above 350 K indicating transition temperature well above room temperature for 2% Mn-doped NiO Nanoparticle. The ferromagnetic Curie temperature is found to be 653 K for the same sample as measured by temperature dependent magnetization study using vibrating sample magnetometer (VSM) in high vacuum. - Highlights: • Mn-doped NiO nanoparticles are prepared by a simple hydrothermal method. • Unit cell volume decreases with increasing doping concentration. • Mn-doping leads to room temperature ferromagnetism in NiO nanoparticles. • Magnetization is highest for 2% Mn-doping. • Above 2%, magnetization decreases with increasing doping.

  5. Room temperature ferromagnetism in Mn-doped NiO nanoparticles

    International Nuclear Information System (INIS)

    Layek, Samar; Verma, H.C.

    2016-01-01

    Mn-doped NiO nanoparticles of the series Ni_1_−_xMn_xO (x=0.00, 0.02, 0.04 and 0.06) are successfully synthesized using a low temperature hydrothermal method. Samples up to 6% Mn-doping are single phase in nature as observed from powder x-ray diffraction (XRD) studies. Rietveld refinement of the XRD data shows that all the single phase samples crystallize in the NaCl like fcc structure with space group Fm-3m. Unit cell volume decreases with increasing Mn-doping. Pure NiO nanoparticles show weak ferromagnetism, may be due to nanosize nature. Introduction of Mn within NiO lattice improves the magnetic properties significantly. Room temperature ferromagnetism is found in all the doped samples whereas the magnetization is highest for 2% Mn-doping and then decreases with further doping. The ZFC and FC branches in the temperature dependent magnetization separate well above 350 K indicating transition temperature well above room temperature for 2% Mn-doped NiO Nanoparticle. The ferromagnetic Curie temperature is found to be 653 K for the same sample as measured by temperature dependent magnetization study using vibrating sample magnetometer (VSM) in high vacuum. - Highlights: • Mn-doped NiO nanoparticles are prepared by a simple hydrothermal method. • Unit cell volume decreases with increasing doping concentration. • Mn-doping leads to room temperature ferromagnetism in NiO nanoparticles. • Magnetization is highest for 2% Mn-doping. • Above 2%, magnetization decreases with increasing doping.

  6. Incubation at room temperature may be an independent factor that induces chlamydospore production in Candida dubliniensis.

    Science.gov (United States)

    Sancak, Banu; Colakoglu, Sule; Acikgoz, Ziya Cibali; Arikan, Sevtap

    2005-08-01

    Production of chlamydospores is one of the phenotypic features used to differentiate Candida albicans and Candida dubliniensis. C. albicans produces few chlamydospores on only cornmeal/rice-Tween agar at room temperature, whereas C. dubliniensis produces abundant chlamydospores at this temperature both on cornmeal agar and some other commonly used media. We tried to determine whether the room temperature is the main factor that induces chlamydospore production of C. dubliniensis, regardless of the medium used. For this purpose, 100 C. albicans and 24 C. dubliniensis isolates were tested for chlamydospore production at room temperature and at 37 degrees C on some routinely used media, including eosin-methylene blue agar (EMB), nutrient agar (NA), nutrient broth (NB), and also on an investigational medium, phenol red agar (PR). At 37 degrees C, none of the isolates produced chlamydospores on any of the tested media. At 26 degrees C, all C. dubliniensis isolates produced abundant chlamydospores and pseudohyphae after 24-48 h on all tested media. At this incubation temperature, all C. albicans isolates failed to produce chlamydospores and pseudohyphae on EMB, NA, and NB, whereas 2 of the C. albicans isolates produced a few chlamydospores on PR. We also observed that all C. dubliniensis isolates tested on EMB and PR produced rough colonies with a hyphal fringe around the colonies, whereas none of the C. albicans isolates showed this property. In conclusion, incubation at 26 degrees C may play the key role for production of abundant chlamydospores and pseudohyphae by C. dubliniensis. Comprehensive molecular studies are needed to clarify the genetic basis of this observation. Using EMB and PR may be an inexpensive, a time-saving, and a simple way of presumptive identification of C. dubliniensis based on chlamydospore formation and colony morphology.

  7. Synthesis, characterization and performance of zinc ferrite nanorods for room temperature sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Archana; Singh, Ajendra [Macromolecular Research Laboratory, Department of Physics, University of Lucknow, Lucknow 226007, U.P. (India); Singh, Satyendra, E-mail: satyendra_nano84@rediffmail.com [Department of Physics, University of Allahabad, Allahabad 211002, U.P. (India); Tandon, Poonam [Macromolecular Research Laboratory, Department of Physics, University of Lucknow, Lucknow 226007, U.P. (India); Yadav, B.C. [Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, U.P. (India); Yadav, R.R. [Department of Physics, University of Allahabad, Allahabad 211002, U.P. (India)

    2015-01-05

    Highlights: • Fabrication of zinc ferrite thin film LPG and CO{sub 2} gas sensors. • Morphological growth of nanorods. • Significant advancement towards the fabrication of a reliable LPG sensor. • A new pathway to produce nanorods as sensorial material. - Abstract: In the present communication, nanorods of zinc ferrite was synthesized and fabricated by employing sol–gel spin coating process. The synthesized material was characterized using X-ray diffraction, scanning electron microscopy, acoustic particle sizer, atomic force microscopy, UV–visible absorption and infrared spectroscopic techniques. Thermal properties were investigated using differential scanning calorimetry. The XRD reveals cubic spinel structure with minimum crystallite size 10 nm. SEM image of the film shows porous surface morphology with uniform distribution of nanorods. The band gap of the zinc ferrite nanorods was found 3.80 eV using the Tauc plot. ZnFe{sub 2}O{sub 4} shows weak super paramagnetic behavior at room temperature investigated using the vibrating sample magnetometer. Further, the liquefied petroleum gas (LPG) and carbon dioxide gas (CO{sub 2}) sensing properties of the fabricated film were investigated at room temperature (25 °C). More variations in electrical resistance were observed for LPG in comparison to CO{sub 2} gas. The parameters such as lattice constant, X-ray density, porosity and specific surface area were also calculated for the better understanding of the observed gas sensing properties. High sensitivity and percentage sensor response, small response and recovery times, good reproducibility and stability characterized the fabricated sensor for the detection of LPG at room temperature.

  8. Integrated Interface Strategy toward Room Temperature Solid-State Lithium Batteries.

    Science.gov (United States)

    Ju, Jiangwei; Wang, Yantao; Chen, Bingbing; Ma, Jun; Dong, Shanmu; Chai, Jingchao; Qu, Hongtao; Cui, Longfei; Wu, Xiuxiu; Cui, Guanglei

    2018-04-25

    Solid-state lithium batteries have drawn wide attention to address the safety issues of power batteries. However, the development of solid-state lithium batteries is substantially limited by the poor electrochemical performances originating from the rigid interface between solid electrodes and solid-state electrolytes. In this work, a composite of poly(vinyl carbonate) and Li 10 SnP 2 S 12 solid-state electrolyte is fabricated successfully via in situ polymerization to improve the rigid interface issues. The composite electrolyte presents a considerable room temperature conductivity of 0.2 mS cm -1 , an electrochemical window exceeding 4.5 V, and a Li + transport number of 0.6. It is demonstrated that solid-state lithium metal battery of LiFe 0.2 Mn 0.8 PO 4 (LFMP)/composite electrolyte/Li can deliver a high capacity of 130 mA h g -1 with considerable capacity retention of 88% and Coulombic efficiency of exceeding 99% after 140 cycles at the rate of 0.5 C at room temperature. The superior electrochemical performance can be ascribed to the good compatibility of the composite electrolyte with Li metal and the integrated compatible interface between solid electrodes and the composite electrolyte engineered by in situ polymerization, which leads to a significant interfacial impedance decrease from 1292 to 213 Ω cm 2 in solid-state Li-Li symmetrical cells. This work provides vital reference for improving the interface compatibility for room temperature solid-state lithium batteries.

  9. One-Dimensional Vanadium Dioxide Nanostructures for Room Temperature Hydrogen Sensors

    Directory of Open Access Journals (Sweden)

    Aline Simo

    2015-06-01

    Full Text Available In relation to hydrogen (H2 economy in general and gas sensing in particular, an extensive set of one dimensional (1-D nano-scaled oxide materials are being investigated as ideal candidates for potential gas sensing applications. This is correlated to their set of singular surface characteristics, shape anisotropy and readiness for integrated devices. Nanostructures of well- established gas sensing materials such as Tin Oxide (SnO2, Zinc Oxide (ZnO, Indium (III Oxide (In2O3, and Tungsten Trioxide (WO3 have shown higher sensitivity and gas selectivity, quicker response, faster time recovery, as well as an enhanced capability to detect gases at low concentrations. While the overall sensing characteristics of these so called 1-D nanomaterials are superior, they are efficient at high temperature; generally above 200 0C. This operational impediment results in device complexities in integration that limit their technological applications, specifically in their miniaturized arrangements. Unfortunately, for room temperature applications, there is a necessity to dope the above mentioned nano-scaled oxides with noble metals such as Platinum (Pt, Palladium (Pd, Gold (Au, Ruthenium (Ru. This comes at a cost. This communication reports, for the first time, on the room temperature enhanced H2 sensing properties of a specific phase of pure Vanadium Dioxide (VO2 phase A in their nanobelt form. The relatively observed large H2 room temperature sensing in this Mott type specific oxide seems to reach values as low as 14 ppm H2 which makes it an ideal gas sensing in H2 fuelled systems.

  10. Discussion of superconducting and room-temperature high-intensity ion linacs

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1996-01-01

    The point of view taken in this discussion is that the basic technology base exists in all essential respects for both superconducting or room-temperature rf linac accelerators and associated power and control systems, and thus a project can make a choice between these technologies on overall system considerations. These include performance, cost, availability, flexibility, and upgradability. Large high-intensity neutron source proposals involving light-ion rf linacs in three categories are reviewed in this context. The categories arc cw linacs to high (∼1 GeV) and low (∼40 MeV) output energy, and pulsed linacs to energy ∼1 GeV

  11. Transforming from paramagnetism to room temperature ferromagnetism in CuO by ball milling

    Directory of Open Access Journals (Sweden)

    Daqiang Gao

    2011-12-01

    Full Text Available In this work, we experimentally demonstrate that it is possible to induce ferromagnetism in CuO by ball milling without any ferromagnetic dopant. The magnetic measurements indicate that paramagnetic CuO is driven to the ferromagnetic state at room temperature by ball milling gradually. The saturation magnetization of the milled powders is found to increase with expanding the milling time and then decrease by annealing under atmosphere. The fitted X-ray photoelectron spectroscopy results indicate that the observed induction and weaken of the ferromagnetism shows close relationship with the valence charged oxygen vacancies (Cu1+-VO in CuO.

  12. Microscopic Superconductivity and Room Temperature Electronics of High-Tc Cuprates

    International Nuclear Information System (INIS)

    Liu Fusui; Chen Wanfang

    2008-01-01

    This paper points out that the Landau criterion for macroscopic superfluidity of He II is only a criterion for microscopic superfluidity of 4 He, extends the Landau criterion to microscopic superconductivity in fermions (electron and hole) system and system with Cooper pairs without long-range phase coherence. This paper gives another three non-superconductive systems that are of microscopic superconductivity. This paper demonstrates that one application of microscopic superconductivity is to establish room temperature electronics of the high-T c cuprates

  13. Resonant exciton-phonon coupling in ZnO nanorods at room temperature

    Directory of Open Access Journals (Sweden)

    Soumee Chakraborty

    2011-09-01

    Full Text Available Vibronic and optoelectronic properties, along with detailed studies of exciton-phonon coupling at room temperature (RT for random and aligned ZnO nanorods are reported. Excitation energy dependent Raman studies are performed for detailed analysis of multi-phonon processes in the nanorods. We report here the origin of coupling between free exciton and its associated phonon replicas, including its higher order modes, in the photoluminescence spectra at RT. Resonance of excitonic electron and resonating first order zone center LO phonon, invoked strongly by Frolich interaction, are made responsible for the observed phenomenon.

  14. Room temperature nanoindentation creep of hot-pressed B6O

    CSIR Research Space (South Africa)

    Machaka, R

    2014-06-01

    Full Text Available of the nanoindentation creep behavior in B6O ceramics. 1 Room temperature nanoindentation creep of hot-pressed B6O Ronald Machakaa,b,* , Trevor E. Derryb,d, Iakovos Sigalasb,c aLight Metals, Materials Science and Manufacturing, Council for Scientific..., University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa dSchool of Physics, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, 2050 South Africa Abstract: Nanoindentation has become a widely...

  15. Gas Transport Properties of PEBAX®/Room Temperature Ionic Liquid Gel Membranes

    Czech Academy of Sciences Publication Activity Database

    Bernardo, P.; Jansen, J. C.; Bazzarelli, F.; Tasselli, F.; Fuoco, A.; Friess, K.; Izák, Pavel; Jarmarová, Veronika; Kačírková, Marie; Clarizia, G.

    2012-01-01

    Roč. 97, SI (2012), s. 73-82 ISSN 1383-5866. [Conference on Ionic Liquids in Separation and Purification Technology (ILSEPT) /1./. Sitges, 04.09.2011-07.09.2011] R&D Projects: GA ČR GAP106/10/1194 Grant - others:RFCS(XE) RFCR-CT-2010-00009 Institutional support: RVO:67985858 Keywords : room temperature ionic liquid * ionic liquid * polymer gel Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.894, year: 2012

  16. Review on numerical modeling of active magnetic regenerators for room temperature applications

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Tusek, Jaka; Engelbrecht, Kurt

    2011-01-01

    The active magnetic regenerator (AMR) is an alternative refrigeration cycle with a potential gain of energy efficiency compared to conventional refrigeration techniques. The AMR poses a complex problem of heat transfer, fluid dynamics and magnetic fields, which requires detailed and robust modeling....... This paper reviews the existing numerical modeling of room temperature AMR to date. The governing equations, implementation of the magnetocaloric effect (MCE), fluid flow and magnetic field profiles, thermal conduction etc. are discussed in detail as is their impact on the AMR cycle. Flow channeling effects...

  17. Thin, Flexible Supercapacitors Made from Carbon Nanofiber Electrodes Decorated at Room Temperature with Manganese Oxide Nanosheets

    OpenAIRE

    Nataraj, S. K.; Song, Q.; Al-Muhtaseb, S. A.; Dutton, S. E.; Zhang, Q.; Sivaniah, E.

    2013-01-01

    We report the fabrication and electrochemical performance of a flexible thin film supercapacitor with a novel nanostructured composite electrode. The electrode was prepared by in situ coprecipitation of two-dimensional (2D) MnO2 nanosheets at room temperature in the presence of carbon nanofibers (CNFs). The highest specific capacitance of 142 F/g was achieved for CNFs-MnO2 electrodes in sandwiched assembly with PVA-H4SiW12O40nH2O polyelectrolyte separator. Peer Reviewed

  18. Ge-Based Spin-Photodiodes for Room-Temperature Integrated Detection of Photon Helicity

    KAUST Repository

    Rinaldi, Christian

    2012-05-02

    Spin-photodiodes based on Fe/MgO/Ge(001) heterostructures are reported. These devices perform the room-temperature integrated electrical detection of the spin polarization of a photocurrent generated by circularly polarized photons with a wavelength of 1300 nm, for light pulses with intensity I 0 down to 200 μW. A forward and reverse-biased average photocurrent variation of 5.9% is measured for the complete reversal of the incident light helicity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Room-temperature plasma-enhanced chemical vapor deposition of SiOCH films using tetraethoxysilane

    International Nuclear Information System (INIS)

    Yamaoka, K.; Yoshizako, Y.; Kato, H.; Tsukiyama, D.; Terai, Y.; Fujiwara, Y.

    2006-01-01

    Carbon-doped silicon oxide (SiOCH) thin films were deposited by room-temperature plasma-enhanced chemical vapor deposition (PECVD) using tetraethoxysilane (TEOS). The deposition rate and composition of the films strongly depended on radio frequency (RF) power. The films deposited at low RF power contained more CH n groups. The SiOCH films showed high etch rate and low refractive index in proportion to the carbon composition. The deposition with low plasma density and low substrate temperature is effective for SiOCH growth by PECVD using TEOS

  20. Effect of room temperature ionic liquid structure on the enzymatic acylation of flavonoids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2010-01-01

    Enzymatic acylation reactions of flavonoids (rutin, esculin) with long chain fatty acids (palmitic, oleic acids) were carried out in 14 different ionic liquid media containing a range of cation and anion structures. Classification of RTILs according to flavonoid solubility (using COSMO...... must be struck that maximized flavonoid solubility with minimum negative impact on lipase activity. The process also benefitted from an increased reaction temperature which may have helped to reduced mass transfer limitations. Keywords: Room temperature ionic liquids (RTILs); Biosynthesis; Acylation......; Flavonoids; Lipase; Long chain fatty acids...

  1. Ti-based bulk metallic glass with high cold workability at room temperature

    International Nuclear Information System (INIS)

    Park, J.M.; Park, J.S.; Kim, J.H.; Lee, M.H.; Kim, D.H.; Kim, W.T.

    2005-01-01

    The cold workability of Ti-based bulk metallic glasses (BMGs) have been investigated. Ti 45 Zr 16 Be 20 Cu 10 Ni 9 BMG with a large compressive plastic strain of 4.7% shows a high cold workability, i.e. total reduction ratio of 50% by cold rolling at room temperature. The multiple shear bands formed during rolling are effective in enhancing the plasticity. The cold rolled Ti 45 Zr 16 Be 20 Cu 10 Ni 9 BMG (reduction ratio: 30%) exhibits a large plastic strain of ∝14%. (orig.)

  2. Thermoelectric Properties of High-Doped Silicon from Room Temperature to 900 K

    Science.gov (United States)

    Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

    2013-07-01

    Silicon is investigated as a low-cost, Earth-abundant thermoelectric material for high-temperature applications up to 900 K. For the calculation of module design the Seebeck coefficient and the electrical as well as thermal properties of silicon in the high-temperature range are of great importance. In this study, we evaluate the thermoelectric properties of low-, medium-, and high-doped silicon from room temperature to 900 K. In so doing, the Seebeck coefficient, the electrical and thermal conductivities, as well as the resulting figure of merit ZT of silicon are determined.

  3. Quantum interference effects at room temperature in OPV-based single-molecule junctions

    DEFF Research Database (Denmark)

    Arroyo, Carlos R.; Frisenda, Riccardo; Moth-Poulsen, Kasper

    2013-01-01

    Interference effects on charge transport through an individual molecule can lead to a notable modulation and suppression on its conductance. In this letter, we report the observation of quantum interference effects occurring at room temperature in single-molecule junctions based on oligo(3......)-phenylenevinylene (OPV3) derivatives, in which the central benzene ring is coupled to either para- or meta-positions. Using the break-junction technique, we find that the conductance for a single meta-OPV3 molecule wired between gold electrodes is one order of magnitude smaller than that of a para-OPV3 molecule...

  4. An acoustic on-chip goniometer for room temperature macromolecular crystallography.

    Science.gov (United States)

    Burton, C G; Axford, D; Edwards, A M J; Gildea, R J; Morris, R H; Newton, M I; Orville, A M; Prince, M; Topham, P D; Docker, P T

    2017-12-05

    This paper describes the design, development and successful use of an on-chip goniometer for room-temperature macromolecular crystallography via acoustically induced rotations. We present for the first time a low cost, rate-tunable, acoustic actuator for gradual in-fluid sample reorientation about varying axes and its utilisation for protein structure determination on a synchrotron beamline. The device enables the efficient collection of diffraction data via a rotation method from a sample within a surface confined droplet. This method facilitates efficient macromolecular structural data acquisition in fluid environments for dynamical studies.

  5. Study of dielectric liquids at room temperature for high energy x ray Tomography

    International Nuclear Information System (INIS)

    Lepert, S.

    1989-09-01

    The detection of X rays by means of a dielectric liquid detector system, at room temperature, is discussed. The physico-chemical properties of a dielectric liquid, the construction of a cleaning device and of two electrode configurations, and the utilization of different amplifier models are studied. The results allowed the analysis and characterization of the behavior of the dielectric liquid under X ray irradiation. Data obtained is confirmed by computerized simulation. The choice of Tetramethyl-germanium for the X ray tomography, applied in nondestructive analysis, is explained. The investigation of the system parameters allowed the setting of the basis of a prototype project for a multi-detector [fr

  6. Thin, Flexible Supercapacitors Made from Carbon Nanofiber Electrodes Decorated at Room Temperature with Manganese Oxide Nanosheets

    Directory of Open Access Journals (Sweden)

    S. K. Nataraj

    2013-01-01

    Full Text Available We report the fabrication and electrochemical performance of a flexible thin film supercapacitor with a novel nanostructured composite electrode. The electrode was prepared by in situ coprecipitation of two-dimensional (2D MnO2 nanosheets at room temperature in the presence of carbon nanofibers (CNFs. The highest specific capacitance of 142 F/g was achieved for CNFs-MnO2 electrodes in sandwiched assembly with PVA-H4SiW12O40·nH2O polyelectrolyte separator.

  7. Tensile properties of unirradiated PCA from room temperature to 7000C

    International Nuclear Information System (INIS)

    Braski, D.N.; Maziasz, P.J.

    1983-01-01

    The tensile properties of Prime Candidate Alloy (PCA) austenitic stainless steel after three different thermomechanical treatments were determined from room temperature to 700 0 C. The solution-annealed PCA had the lowest strength and highest ductility, while the reverse was true for the 25%-cold-worked material. The PCA containing titanium-rich MC particles fell between the other two heats. The cold-worked PCA had nearly the same tensile properties as cold-worked type 316 stainless steel. Both alloys showed ductility minima at 300 0 C

  8. Mid-infrared coincidence measurements on twin photons at room temperature

    DEFF Research Database (Denmark)

    Mancinelli, M.; Trenti, A.; Piccione, S.

    2017-01-01

    Quantum measurements using single-photon detectors are opening interesting new perspectives in diverse fields such as remote sensing, quantum cryptography and quantum computing. A particularly demanding class of applications relies on the simultaneous detection of correlated single photons...... pave the way to quantum measurements in the MIR by the demonstration of a room temperature coincidence measurement with non-degenerate twin photons at about 3.1 mu m. The experiment is based on the spectral translation of MIR radiation into the visible region, by means of efficient up-converter modules...

  9. Electrical characterization of MIM capacitor comprises an adamantane film at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Rajanish N., E-mail: rajanisht@gmail.com [Department of Physics and Astronomical Sciences, Central University of Himachal Pradesh, Dharmshala 176206 Kangra, H.P. India (India); Toyota Technological Institute, 2-12-1Hisakata, Tempaku-Ku, Nagoya 468-8511 (Japan); Yoshimura, Masamichi [Department of Physics and Astronomical Sciences, Central University of Himachal Pradesh, Dharmshala 176206 Kangra, H.P. India (India)

    2016-06-15

    We fabricated a new metal-insulator-metal capacitor at room temperature, comprising a ∼90 nm thin low–k adamantane film on a Si substrate. The surface morphology of deposited organic film was investigated by using scanning electron microscopy and Raman spectroscopy, which is confirmed that the adamantane thin film was uniformly distributed on the Si surface. The adamantane film exhibits a low leakage current density of 7.4 x 10{sup −7} A/cm{sup 2} at 13.5 V, better capacitance density of 2.14 fF/μm{sup 2} at 100 KHz.

  10. Spectroscopic evidence for 5f bands at room temperature in uranium-based heavy fermions

    International Nuclear Information System (INIS)

    Arko, A.J.; Koelling, D.D.; Dunlap, B.D.; Capasso, C.; del Giudice, M.

    1988-01-01

    We present data on the alloy system UPd/sub 3-x/Pt/sub x/ and show that in the double hexagonal phase (x 2.4) as well, except that the low-binding energy feature is locked in at E/sub F/ and shows evidence of energy dispersion at room temperature/endash/consistent with well-defined bands. Conversely, we show that even in well-behaved narrow band systems (USn 3 there is evidence for satellite formation. 44 refs., 8 figs

  11. Statistical analysis of LHC main interconnection splices room temperature resistance (R-8) results

    CERN Document Server

    Heck, S

    2012-01-01

    During the 2008/2009 shutdown the so-called R-8/R-16 room temperature resistance test has been introduced for the quality control of the LHC main interconnection splices. It has been found that at present two groups of LHC main interconnection splices can be distinguished, so-called “old” splices produced during LHC installation, and so-called “new” splices produced during 2009. 2009 production splices are considered as the state-of-the art, which is reflected by a much smaller R-8 distribution as compared to that of splices produced during first LHC installation.

  12. Room-Temperature Voltage Tunable Phonon Thermal Conductivity via Reconfigurable Interfaces in Ferroelectric Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Ihlefeld, Jon F. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Foley, Brian M. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Mechanical and Aerospace Engineering; Scrymgeour, David A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Michael, Joseph R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); McKenzie, Bonnie B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Medlin, Douglas L. [Sandia National Laboratories, Livermore, CA; Wallace, Margeaux [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering; Trolier-McKinstry, Susan [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering; Hopkins, Patrick E. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Mechanical and Aerospace Engineering

    2015-02-19

    Dynamic control of thermal transport in solid-state systems is a transformative capability with the promise to propel technologies including phononic logic, thermal management, and energy harvesting. A solid-state solution to rapidly manipulate phonons has escaped the scientific community. Here, we demonstrate active and reversible tuning of thermal conductivity by manipulating the nanoscale ferroelastic domain structure of a Pb(Zr0.3Ti0.7)O3 film with applied electric fields. With subsecond response times, the room-temperature thermal conductivity was modulated by 11%.

  13. Low cryogen inventory, forced flow Ne cooling system with room temperature compression stage and heat recuperation

    CERN Document Server

    Shornikov, A; Wolf, A

    2014-01-01

    We present design and commissioning results of a forced flow cooling system utilizing neon at 30 K. The cryogen is pumped through the system by a room-temperature compression stage. To decouple the cold zone from the compression stage a recuperating counterflow tube-in-tube heat exchanger is used. Commissioning demonstrated successful condensation of neon and transfer of up to 30 W cooling power to the load at 30 K using only 30 g of the cryogen circulating in the system at pressures below 170 kPa.

  14. Magnetic properties of CoP alloys electrodeposited at room temperature

    International Nuclear Information System (INIS)

    Lucas, I.; Perez, L.; Aroca, C.; Sanchez, P.; Lopez, E.; Sanchez, M.C.

    2005-01-01

    CoP alloys have been electrodeposited at room temperature from electrolytes with different pH values and their magnetic properties have been studied. Cracks and fractures appear when using stiff substrates, showing that high internal stresses, due to hydrogen evolution, are involved in the electrodeposition process. Samples electrodeposited onto flexible substrates do not show cracks on the surface. We also report an increment in the coercivity of the alloys when the pH of the electrolyte decreases, and therefore, the hydrogen evolution and the internal stresses increase

  15. Heavy atom enhanced room-temperature phosphorimetry for ultratrace determination of harmane

    OpenAIRE

    Flávia F. de Carvalho Marques; Flávia da Silva Figueiredo; Ricardo Queiroz Aucelio

    2008-01-01

    Harmane has been proposed for the treatment of epilepsy, AIDS and leshmaniosis. Its room-temperature phosphorescence was induced using either AgNO3 or TlNO3, enabling absolute limits of detection of 0.12 and 2.4 ng respectively, with linear dynamic ranges extending up to 456 ng (AgNO3) and 911 ng (TlNO3). Relative standard deviations around 3% were observed for substrates containing 46 ng of harmane. Such sensitivity and precision are needed because harmane intake must be strictly controlled ...

  16. Room-temperature voltage tunable phonon thermal conductivity via reconfigurable interfaces in ferroelectric thin films.

    Science.gov (United States)

    Ihlefeld, Jon F; Foley, Brian M; Scrymgeour, David A; Michael, Joseph R; McKenzie, Bonnie B; Medlin, Douglas L; Wallace, Margeaux; Trolier-McKinstry, Susan; Hopkins, Patrick E

    2015-03-11

    Dynamic control of thermal transport in solid-state systems is a transformative capability with the promise to propel technologies including phononic logic, thermal management, and energy harvesting. A solid-state solution to rapidly manipulate phonons has escaped the scientific community. We demonstrate active and reversible tuning of thermal conductivity by manipulating the nanoscale ferroelastic domain structure of a Pb(Zr0.3Ti0.7)O3 film with applied electric fields. With subsecond response times, the room-temperature thermal conductivity was modulated by 11%.

  17. Room temperature microwave-assisted recording on 500-Gbpsi-class perpendicular medium

    Science.gov (United States)

    Nozaki, Y.; Ishida, N.; Soeno, Y.; Sekiguchi, K.

    2012-10-01

    Microwave-assisted recording on a 500-Gbpsi-class perpendicular medium was experimentally demonstrated at room temperature. Magnetization reversal under a radio-frequency magnetic field was measured by an electrically shorted coplanar waveguide, which enabled us to evaluate the change in the medium's ferromagnetic resonance spectrum. A frequency-dependent reduction in the switching field was clearly observed in response to a microwave impulse 50 ns in duration. A significant reduction of up to 30% in the coercive field was achieved by applying a microwave impulse with an amplitude of 25 dBm and a frequency of 15 GHz.

  18. Room-Temperature Spin-Orbit Torque Switching Induced by a Topological Insulator

    Science.gov (United States)

    Han, Jiahao; Richardella, A.; Siddiqui, Saima A.; Finley, Joseph; Samarth, N.; Liu, Luqiao

    2017-08-01

    The strongly spin-momentum coupled electronic states in topological insulators (TI) have been extensively pursued to realize efficient magnetic switching. However, previous studies show a large discrepancy of the charge-spin conversion efficiency. Moreover, current-induced magnetic switching with TI can only be observed at cryogenic temperatures. We report spin-orbit torque switching in a TI-ferrimagnet heterostructure with perpendicular magnetic anisotropy at room temperature. The obtained effective spin Hall angle of TI is substantially larger than the previously studied heavy metals. Our results demonstrate robust charge-spin conversion in TI and provide a direct avenue towards applicable TI-based spintronic devices.

  19. Transistor effects and in situ STM of redox molecules at room temperature

    DEFF Research Database (Denmark)

    Albrecht, Tim; Guckian, A; Vos, JG

    2005-01-01

    . It predicts a distinct increase of the tunnelling current close to the equilibrium potential, i.e., if molecular bridge states are tuned into resonance with the Fermi levels of the enclosing electrodes. The complexes display robust electrochemistry on Au(111) electrode surfaces. STM images at molecular......Inorganic transition metal complexes were identified as potential candidates for transistor-like behavior in an electrochemical scanning tunnelling microscope (STM) configuration at room temperature. The theoretical background has been established based on condensed matter charge transfer theory...... resolution reveal detailed information on their surface structure and scanning tunnelling spectroscopy experiments have shown clear evidence of transistor-like behavior...

  20. Room temperature fatigue behavior of OFHC copper and CuAl25 specimens of two sizes

    DEFF Research Database (Denmark)

    Singhal, A.; Stubbins, J.F.; Singh, B.N.

    1994-01-01

    requiring an understanding of their fatigue behavior.This paper describes the room temperature fatigue behavior of unirradiated OFHC (oxygen-free high-conductivity) copper and CuAl25 (copper strengthened with a 0.25% atom fraction dispersion of alumina). The response of two fatigue specimen sizes to strain......Copper and its alloys are appealing for application in fusion reactor systems for high heat flux components where high thermal conductivities are critical, for instance, in divertor components. The thermal and mechanical loading of such components will be, at least in part, cyclic in nature, thus...

  1. An environment-friendly microemulsion approach to α-FeOOH nanorods at room temperature

    International Nuclear Information System (INIS)

    Geng Fengxia; Zhao Zhigang; Cong Hongtao; Geng Jianxin; Cheng Huiming

    2006-01-01

    α-FeOOH nanorods have been prepared at room temperature by an environment-friendly microemulsion approach. X-ray diffraction and transmission electron microscopy revealed that the single-crystalline orthorhombic α-FeOOH nanorods are 8.2 ± 1.5 nm in diameter and 106 ± 16 nm in length. Furthermore, the mechanism for the formation of α-FeOOH nanorods is preliminarily presented. This method may be widely used for reference to fabricate other inorganic one-dimensional nanostructured materials and easily realized in industrial-scale synthesis

  2. Room-temperature synthesis and photoluminescence of hexagonal CePO4 nanorods

    Science.gov (United States)

    Zhu, J.; Zhang, K.; Zhao, H. Y.

    2018-01-01

    Hexagonal CePO4 nanorods were synthesized via a simple chemical precipitation route at room-temperature without the presence of surfactants and then characterized by powder X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption and photoluminescence (PL) spectroscopy. Hexagonal CePO4 nanorods exhibit strong ultraviolet absorption and ultraviolet luminescence, which correspond to the electronic transitions between 4f and 5d state of Ce3+ ions.

  3. Hyperbaric storage at room temperature for food preservation: A study in strawberry juice

    OpenAIRE

    Segovia-Bravo, Kharla A.; Guignon, Bérengère; Bermejo-Prada, Ana; Sanz Martínez, Pedro D.; Otero, Laura

    2012-01-01

    Hyperbaric storage at room temperature was evaluated as a new food preservation method. To do that, strawberry juices maintained at different pressure levels (0.1, 25, 100 or 220 MPa) and 20°C for 15 days were compared to raw and thermally pasteurized samples stored at atmospheric pressure and 5°C for the same period. Hyperbaric storage reduced the initial microbial load of the juices by more than 2 log units to levels below the limit of detection. Moreover, pressure was effective to attenuat...

  4. Fuzzy Analogues of Sets and Functions Can Be Uniquely Determined from the Corresponding Ordered Category: A Theorem

    Directory of Open Access Journals (Sweden)

    Christian Servin

    2018-01-01

    Full Text Available In modern mathematics, many concepts and ideas are described in terms of category theory. From this viewpoint, it is desirable to analyze what can be determined if, instead of the basic category of sets, we consider a similar category of fuzzy sets. In this paper, we describe a natural fuzzy analog of the category of sets and functions, and we show that, in this category, fuzzy relations (a natural fuzzy analogue of functions can be determined in category terms—of course, modulo 1-1 mapping of the corresponding universe of discourse and 1-1 re-scaling of fuzzy degrees.

  5. Observation of Various and Spontaneous Magnetic Skyrmionic Bubbles at Room Temperature in a Frustrated Kagome Magnet with Uniaxial Magnetic Anisotropy

    KAUST Repository

    Hou, Zhipeng; Ren, Weijun; Ding, Bei; Xu, Guizhou; Wang, Yue; Yang, Bing; Zhang, Qiang; Zhang, Ying; Liu, Enke; Xu, Feng; Wang, Wenhong; Wu, Guangheng; Zhang, Xixiang; Shen, Baogen; Zhang, Zhidong

    2017-01-01

    to various external stimuli acting as information carriers in spintronic devices. Here, the first observation of skyrmionic magnetic bubbles with variable topological spin textures formed at room temperature in a frustrated kagome Fe3 Sn2 magnet with uniaxial

  6. Room-temperature synthesis of ultraviolet-emitting nanocrystalline GaN films using photochemical vapor deposition

    International Nuclear Information System (INIS)

    Yamazaki, Shunsuke; Yatsui, Takashi; Ohtsu, Motoichi; Kim, Taw-Won; Fujioka, Hiroshi

    2004-01-01

    We fabricated UV-emitting nanocrystalline gallium nitride (GaN) films at room temperature using photochemical vapor deposition (PCVD). For the samples synthesized at room temperature with V/III ratios exceeding 5.0x10 4 , strong photoluminescence peaks at 3.365 and 3.310 eV, which can be ascribed to transitions in a mixed phase of cubic and hexagonal GaN, were observed at 5 K. A UV emission spectrum with a full width at half-maximum of 100 meV was observed, even at room temperature. In addition, x-ray photoelectron spectroscopy measurement revealed that the film deposited by PCVD at room temperature was well nitridized

  7. An experimental study of the effect of different starting room temperatures on occupant comfort in Danish summer weather

    DEFF Research Database (Denmark)

    Bourdakis, Eleftherios; Simone, Angela; Olesen, Bjarne W.

    2018-01-01

    As office workers will usually have a slightly elevated metabolic rate when arriving at work, they may prefer a room temperature below the comfort range for sedentary activity in the morning. This possibility was studied in an experiment with 25 young people, male and female, exposed to four diff...... be maintained in the early office hours, and that this will lead to a lower maximum room temperature during the day, which would result in less demand for cooling during the summer period....

  8. Room temperature synthesis of porous SiO2 thin films by plasma enhanced chemical vapor deposition

    OpenAIRE

    Barranco Quero, Ángel; Cotrino Bautista, José; Yubero Valencia, Francisco; Espinós, J. P.; Rodríguez González-Elipe, Agustín

    2004-01-01

    Synthesis of porous SiO2 thin films in room temperature was carried out using plasma enhanced chemical vapor deposition (CVD) in an electron cyclotron resonance microwave reactor with a downstream configuration.The gas adsorption properties and the type of porosity of the SiO2 thin films were assessed by adsorption isotherms of toluene at room temperature.The method could also permit the tailoring synthesis of thin films when both composition and porosity can be simultaneously and independent...

  9. Performance of room temperature mercuric iodide (HgI2) detectors in the ultra low energy x-ray region

    International Nuclear Information System (INIS)

    Dabrowski, A.J.; Iwanczyk, J.S.; Barton, J.B.; Huth, G.C.; Whited, R.; Ortale, C.; Economou, T.E.; Turkevich, A.L.

    1980-01-01

    Performance of room temperature mercuric iodide x-ray spectrometers has been recently improved through new fabrication techniques and further development of low noise associated electronic systems. This progress has extended the range of measurements to the ultra low energy x-ray region at room temperature. This paper reports the study of the effect of contact material on the performance of HgI 2 detectors in the low energy x-ray region

  10. Controllable synthesis of Co3O4/polyethyleneimine-carbon nanotubes nanocomposites for CO and NH3 gas sensing at room temperature

    International Nuclear Information System (INIS)

    Lin, Yufei; Kan, Kan; Song, Wanzhen; Zhang, Guo; Dang, Lifang; Xie, Yu; Shen, Peikang; Li, Li; Shi, Keying

    2015-01-01

    Graphical abstract: Co 3 O 4 /polyethyleneimine-carbon nanotubes composites (CoPCNTs) have been successfully controllable synthesized via hydrothermal method at different temperature. The CoPCNTs sensors exhibited the highest response to CO and NH 3 gases with response time of 4 s and 4.3 s, low detection limit of 5 ppm and 1 ppm at room temperature, respectively. The enhanced gas sensing could be ascribed to the synergistic effect between the tiny size of Co 3 O 4 and good conductivity of carbon nanotubes functionalized by polyethyleneimine. - Highlights: • The CNTs functionalized by polyethyleneimine provided a new functional structural. • The novel 1D structure could capture and migrate electrons quickly. • The Co 3 O 4 nanoparticles liked a snake winding around CNTs. • The gas sensor could work at room temperatures, which suit to practical application. - Abstract: A novel 1D Co 3 O 4 /polyethyleneimine-carbon nanotubes composites (CoPCNTs) have been successfully synthesized via hydrothermal method at different temperature. The CNTs functionalized by polyethyleneimine (PCNTs) provided a new material with new structural and functional properties. The PCNTs was used as loading guider and electron transfer path. The Co 3 O 4 nanoparticles (NPs) loaded on the PCNTs surface liked a snake winding around CNTs, and the size was about 5–10 nm. The gas sensing characteristics of the CoPCNTs sensors to carbon monoxide (CO) and ammonia (NH 3 ) were evaluated with different gas concentration. The CoPCNTs sensors grown at 160 °C exhibited the highest response to CO and NH 3 gases with response time of 4 s and 4.3 s at room temperature (RT), respectively. Hence, the approach developed in this work would be important for the low-cost and large-scale production of the CoPCNTs materials with highly promising applications in gas sensors

  11. Ultrasonic acoustic levitation for fast frame rate X-ray protein crystallography at room temperature

    Science.gov (United States)

    Tsujino, Soichiro; Tomizaki, Takashi

    2016-05-01

    Increasing the data acquisition rate of X-ray diffraction images for macromolecular crystals at room temperature at synchrotrons has the potential to significantly accelerate both structural analysis of biomolecules and structure-based drug developments. Using lysozyme model crystals, we demonstrated the rapid acquisition of X-ray diffraction datasets by combining a high frame rate pixel array detector with ultrasonic acoustic levitation of protein crystals in liquid droplets. The rapid spinning of the crystal within a levitating droplet ensured an efficient sampling of the reciprocal space. The datasets were processed with a program suite developed for serial femtosecond crystallography (SFX). The structure, which was solved by molecular replacement, was found to be identical to the structure obtained by the conventional oscillation method for up to a 1.8-Å resolution limit. In particular, the absence of protein crystal damage resulting from the acoustic levitation was carefully established. These results represent a key step towards a fully automated sample handling and measurement pipeline, which has promising prospects for a high acquisition rate and high sample efficiency for room temperature X-ray crystallography.

  12. Origin of room temperature ferromagnetism in SnO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing [School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Bai, Guohua; Jiang, Yinzhu [School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Du, Youwei [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Wu, Chen, E-mail: chen_wu@zju.edu.cn [School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Yan, Mi, E-mail: mse_yanmi@zju.edu.cn [School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)

    2017-03-15

    SnO{sub 2} films exhibiting room temperature ferromagnetism (RTFM) have been prepared on Si (001) by pulsed laser deposition. The saturation magnetization (M{sub s}) of the films experiences a decreasing trend followed by increasing with the growth temperature increased from RT to 400 ℃. The growth temperature affects both the concentration and the location of the oxygen vacancies as the origin of the RTFM. With lower growth temperatures (<300 ℃), more oxygen vacancies exist in the inner film for the samples with less crystallinity, resulting in enhanced magnetism. Higher deposition temperature leads to less oxygen vacancies in the inner film but more oxygen defects at the film surface, which is also beneficial to achieve greater magnetism. Various oxygen pressures during growth and post-annealing have also been used to confirm the role of oxygen vacancies. The study demonstrates that the surface oxygen defects and the positively charged monovalent O vacancies (V{sub O}{sup +}) in the inner film are the origin of the magnetism in SnO{sub 2} films. - Highlights: • SnO{sub 2} films exhibiting room temperature ferromagnetism (RTFM) have been prepared on Si (001) by pulsed laser deposition. • Growth temperature, oxygen pressure and annealing affect the growth of SnO{sub 2} films. • Both the concentration and location of the oxygen vacancies play critical roles in the magnetization.

  13. Polyaniline-Cadmium Ferrite Nanostructured Composite for Room-Temperature Liquefied Petroleum Gas Sensing

    Science.gov (United States)

    Kotresh, S.; Ravikiran, Y. T.; Tiwari, S. K.; Vijaya Kumari, S. C.

    2017-08-01

    We introduce polyaniline-cadmium ferrite (PANI-CdFe2O4) nanostructured composite as a room-temperature-operable liquefied petroleum gas (LPG) sensor. The structure of PANI and the composite prepared by chemical polymerization was characterized by Fourier-transform infrared (FT-IR) spectroscopy, x-ray diffraction (XRD) analysis, and field-emission scanning electron microscopy. Comparative XRD and FT-IR analysis confirmed CdFe2O4 embedded in PANI matrix with mutual interfacial interaction. The nanostructure of the composite was confirmed by transmission electron microscopy. A simple LPG sensor operable at room temperature, exclusively based on spin-coated PANI-CdFe2O4 nanocomposite, was fabricated with maximum sensing response of 50.83% at 1000 ppm LPG. The response and recovery time of the sensor were 50 s and 110 s, respectively, and it was stable over a period of 1 month with slight degradation of 4%. The sensing mechanism is discussed on the basis of the p- n heterojunction barrier formed at the interface of PANI and CdFe2O4.

  14. Molecular dynamics study of room temperature ionic liquids with water at mica surface

    Directory of Open Access Journals (Sweden)

    Huanhuan Zhang

    2018-04-01

    Full Text Available Water in room temperature ionic liquids (RTILs could impose significant effects on their interfacial properties at a charged surface. Although the interfaces between RTILs and mica surfaces exhibit rich microstructure, the influence of water content on such interfaces is little understood, in particular, considering the fact that RTILs are always associated with water due to their hygroscopicity. In this work, we studied how different types of RTILs and different amounts of water molecules affect the RTIL-mica interfaces, especially the water distribution at mica surfaces, using molecular dynamics (MD simulation. MD results showed that (1 there is more water and a thicker water layer adsorbed on the mica surface as the water content increases, and correspondingly the average location of K+ ions is farther from mica surface; (2 more water accumulated at the interface with the hydrophobic [Emim][TFSI] than in case of the hydrophilic [Emim][BF4] due to the respective RTIL hydrophobicity and ion size. A similar trend was also observed in the hydrogen bonds formed between water molecules. Moreover, the 2D number density map of adsorbed water revealed that the high-density areas of water seem to be related to K+ ions and silicon/aluminum atoms on mica surface. These results are of great importance to understand the effects of hydrophobicity/hydrophicility of RTIL and water on the interfacial microstructure at electrified surfaces. Keywords: Room temperature ionic liquids, Hydrophobicity/hydrophicility, Water content, Electrical double layer, Mica surface

  15. Fabrication and Microstructure of Hydroxyapatite Coatings on Zirconia by Room Temperature Spray Process.

    Science.gov (United States)

    Seo, Dong Seok; Chae, Hak Cheol; Lee, Jong Kook

    2015-08-01

    Hydroxyapatite coatings were fabricated on zirconia substrates by a room temperature spray process and were investigated with regards to their microstructure, composition and dissolution in water. An initial hydroxyapatite powder was prepared by heat treatment of bovine-bone derived powder at 1100 °C for 2 h, while dense zirconia substrates were fabricated by pressing 3Y-TZP powder and sintering it at 1350 °C for 2 h. Room temperature spray coating was performed using a slit nozzle in a low pressure-chamber with a controlled coating time. The phase composition of the resultant hydroxyapatite coatings was similar to that of the starting powder, however, the grain size of the hydroxyapatite particles was reduced to about 100 nm due to their formation by particle impaction and fracture. All areas of the coating had a similar morphology, consisting of reticulated structure with a high surface roughness. The hydroxyapatite coating layer exhibited biostability in a stimulated body fluid, with no severe dissolution being observed during in vitro experimentation.

  16. Microstructure evolution during cyclic tests on EUROFER 97 at room temperature. TEM observation and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Giordana, M.F., E-mail: giordana@ifir-conicet.gov.ar [Instituto de Fisica Rosario, CONICET-UNR, Bv. 27 de Febrero 210 Bis, 2000 Rosario (Argentina); Giroux, P.-F. [Commissariat a l' Energie Atomique, DEN/DANS/DMN/SRMA, 91191 Gif-sur-Yvette Cedex (France); Alvarez-Armas, I. [Instituto de Fisica Rosario, CONICET-UNR, Bv. 27 de Febrero 210 Bis, 2000 Rosario (Argentina); Sauzay, M. [Commissariat a l' Energie Atomique, DEN/DANS/DMN/SRMA, 91191 Gif-sur-Yvette Cedex (France); Armas, A. [Instituto de Fisica Rosario, CONICET-UNR, Bv. 27 de Febrero 210 Bis, 2000 Rosario (Argentina); Kruml, T. [CEITEC IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Zizkova 22, Brno, 616 62 (Czech Republic)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer Low cycle fatigue test are carried out on EUROFER 97 at room temperature. Black-Right-Pointing-Pointer EUROFER 97 shows a pronounced cyclic softening accompanied by microstructural changes. Black-Right-Pointing-Pointer Cycling induces a decrement in dislocation density and subgrain growth. Black-Right-Pointing-Pointer A simple mean-field model based on crystalline plasticity is proposed. Black-Right-Pointing-Pointer The mean subgrain size evolution is predicted by modelling. - Abstract: The 9% Cr quenched and tempered reduced-activation ferritic/martensitic steel EUROFER 97 is one of the candidates for structural components of fusion reactors. Isothermal, plastic strain-controlled, low-cycle fatigue tests are performed. Tested at room temperature, this steel suffers a cyclic softening effect linked to microstructural changes observed by transmission electron microscopy, such as the decrease of dislocation density inside subgrains or the growth of subgrain size. From the assumed mechanisms of softening a simple mean-field model based on crystalline plasticity is proposed to predict these microstructure evolutions during cycling and monotonic deformation.

  17. Room-temperature near-infrared electroluminescence from boron-diffused silicon pn junction diodes

    Directory of Open Access Journals (Sweden)

    Si eLi

    2015-02-01

    Full Text Available Silicon pn junction diodes with different doping concentrations were prepared by boron diffusion into Czochralski (CZ n-type silicon substrate. Their room-temperature near-infrared electroluminescence (EL was measured. In the EL spectra of the heavily boron doped diode, a luminescence peak at ~1.6 m (0.78 eV was observed besides the band-to-band line (~1.1eV under the condition of high current injection, while in that of the lightly boron doped diode only the band-to-band line was observed. The intensity of peak at 0.78 eV increases exponentially with current injection with no observable saturation at room temperature. Furthermore, no dislocations were found in the cross-sectional transmission electron microscopy image, and no dislocation-related luminescence was observed in the low-temperature photoluminescence spectra. We deduce the 0.78 eV emission originates from the irradiative recombination in the strain region of diodes caused by the diffusion of large number of boron atoms into silicon crystal lattice.

  18. Unexpected large room-temperature ferromagnetism in porous Cu{sub 2}O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xue [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Sun, Huiyuan, E-mail: huiyuansun@126.com [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China); Liu, Lihu; Jia, Xiaoxuan; Liu, Huiyuan [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Advanced Films of Hebei Province, Shijiazhuang 050024 (China)

    2015-05-15

    Porous Cu{sub 2}O films have been fabricated on porous anodic alumina substrates using DC-reactive magnetron sputtering with pure Cu targets, and unexpectedly large room temperature ferromagnetism has been observed in the films. The maximum saturation magnetic moment along the out-of-plane direction was as high as 94 emu/cm{sup 3}. Photoluminescence spectra show that the ferromagnetism originates with oxygen vacancies. The ferromagnetism could be adjusted by changing the concentration of oxygen vacancies through annealing in an oxygen atmosphere. These observations suggest that the origin of the ferromagnetism is due to coupling between oxygen vacancies with local magnetic moments in the porous Cu{sub 2}O films, which can occur either directly through exchange interactions between oxygen vacancies, or through the mediation of conduction electrons. Such a ferromagnet without the presence of any ferromagnetic dopant may find applications in spintronic devices. - Highlights: • Porous Cu{sub 2}O films were deposited on porous anodic alumina (PAA) substrates. • Significant room-temperature ferromagnetism has been observed in porous Cu{sub 2}O films. • Ferromagnetism of Cu{sub 2}O films exhibited different magnetic signals with the field. • The saturation magnetization is 94 emu/cm{sup 3} with an out-of-plane.

  19. Room temperature ferromagnetism of nanocrystalline Nd1.90Ni0.10O3-δ

    Science.gov (United States)

    Sarkar, B. J.; Mandal, J.; Dalal, M.; Bandyopadhyay, A.; Chakrabarti, P. K.

    2018-05-01

    Nanocrystalline sample of Ni2+ doped neodymium oxide (Nd1.90Ni0.10O3-δ, NNO) is synthesized by co-precipitation method. Analysis of X-ray diffraction (XRD) pattern by Rietveld refinement method confirms the desired phase of NNO and complete substitution of Ni2+ ions in the Nd2O3 lattice. Analyses of transmission electron microscopy (TEM) and Raman spectroscopy of NNO recorded at room temperature (RT) also substantiate this fact. Besides, no traces of impurities are found in the analyses of XRD, TEM and Raman data. Room temperature hysteresis loop of NNO suggests the presence of weak ferromagnetism (FM) in low field region ( 600 mT), but in high field region paramagnetism of the host is more prominent. Magnetization vs. temperature ( M- T) curve in the entire temperature range (300-5 K) is analyzed successfully by a combined equation generated from three-dimensional (3D) spin wave model and Curie-Weiss law, which suggests the presence of mixed paramagnetic phase together with ferromagnetic phase in the doped sample. The onset of magnetic ordering is analyzed by oxygen vacancy mediated F-center exchange (FCE) coupling mechanism.

  20. Room temperature ammonia and VOC sensing properties of CuO nanorods

    International Nuclear Information System (INIS)

    Bhuvaneshwari, S.; Gopalakrishnan, N.

    2016-01-01

    Here, we report a NH 3 and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

  1. γ-irradiation induced zinc ferrites and their enhanced room-temperature ammonia gas sensing properties

    Science.gov (United States)

    Raut, S. D.; Awasarmol, V. V.; Ghule, B. G.; Shaikh, S. F.; Gore, S. K.; Sharma, R. P.; Pawar, P. P.; Mane, R. S.

    2018-03-01

    Zinc ferrite (ZnFe2O4) nanoparticles (NPs), synthesized using a facile and cost-effective sol-gel auto-combustion method, were irradiated with 2 and 5 kGy γ-doses using 60Co as a radioactive source. Effect of γ-irradiation on the structure, morphology, pore-size and pore-volume and room-temperature (300 K) gas sensor performance has been measured and reported. Both as-synthesized and γ-irradiated ZnFe2O4 NPs reveal remarkable gas sensor activity to ammonia in contrast to methanol, ethanol, acetone and toluene volatile organic gases. The responses of pristine, 2 and 5 kGy γ-irradiated ZnFe2O4 NPs are respectively 55%, 66% and 81% @100 ppm concentration of ammonia, signifying an importance of γ-irradiation for enhancing the sensitivity, selectivity and stability of ZnFe2O4 NPs as ammonia gas sensors. Thereby, due to increase in surface area and crystallinity on γ-doses, the γ-irradiation improves the room-temperature ammonia gas sensing performance of ZnFe2O4.

  2. Room temperature ammonia and VOC sensing properties of CuO nanorods

    Science.gov (United States)

    Bhuvaneshwari, S.; Gopalakrishnan, N.

    2016-05-01

    Here, we report a NH3 and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

  3. Room temperature synthesis of a Zn(II) metal-organic coordination polymer for dye removal

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Alireza, E-mail: aabbasi@khayam.ut.ac.ir [School of Chemistry, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Gharib, Maniya; Najafi, Mahnaz [School of Chemistry, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Janczak, Jan [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wrocław (Poland)

    2016-03-15

    A new one-dimensional (1D) coordination polymer, [Zn(4,4′-bpy)(H{sub 2}O){sub 4}](ADC)·4H{sub 2}O (1) (4,4′-bpy=4,4′-bipyridine and H{sub 2}ADC=acetylenedicarboxylic acid), was synthesized at room temperature. The crystal structure of the coordination polymer was determined by single-crystal X-ray diffraction analysis. Compound 1 was also characterized by FT-IR, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). The catalytic activity of 1 was evaluated in the color removal of Bismarck brown as a representative of dye pollutant in water under mild conditions. Coordination polymer 1 exhibited good catalytic activity and stability in the decolorization of Bismarck brown and could be easily recovered and reused for at least three cycles. - Graphical abstract: A new 1D coordination polymer as catalyst for the degradation of Bismarck brown aqueous solution. - Highlights: • A 1D coordination polymer has been synthesized at room temperature. • The prepared compound was utilized for color removal of Bismarck brown dye. • Good catalytic activity and stability in the dye decolorization has been found.

  4. Towards a Room-Temperature Spin Quantum Bus in Diamond via Electron Photoionization, Transport, and Capture

    Directory of Open Access Journals (Sweden)

    M. W. Doherty

    2016-11-01

    Full Text Available Diamond is a proven solid-state platform for spin-based quantum technology. The nitrogen-vacancy center in diamond has been used to realize small-scale quantum information processing and quantum sensing under ambient conditions. A major barrier in the development of large-scale quantum information processing in diamond is the connection of nitrogen-vacancy spin registers by a quantum bus at room temperature. Given that diamond is expected to be an ideal spin transport material, the coherent transport of spin directly between the spin registers offers a potential solution. Yet, there has been no demonstration of spin transport in diamond due to difficulties in achieving spin injection and detection via conventional methods. Here, we exploit detailed knowledge of the paramagnetic defects in diamond to identify novel mechanisms to photoionize, transport, and capture spin-polarized electrons in diamond at room temperature. Having identified these mechanisms, we explore how they may be combined to realize an on-chip spin quantum bus.

  5. Thermophysical and spectroscopic studies of room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate in Tritons

    International Nuclear Information System (INIS)

    Chaudhary, Ganga Ram; Bansal, Shafila; Mehta, S.K.; Ahluwalia, A.S.

    2012-01-01

    Highlights: ► Thermophysical studies of new formulations of [BMIM][PF 6 ]+TX(45,100) have been made. ► Strong intermolecular interactions between [BMIM][PF 6 ] and TX (45, 100) is observed. ► Magnitude of interactions increases with the addition of oxyethylene groups in TX. ► With rise in temperature, intermolecular interactions increases. ► Spectroscopic studies show that interactions are via aromatic rings of RTIL and TX. - Abstract: The thermophysical properties viz. density ρ, speed of sound u, and specific conductivity κ of pure room temperature ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and its binary formulations with Triton X-45 and Triton X-100 have been studied over the entire composition range at different temperatures (293.15 to 323.15) K. Excess molar volume V E , deviation in isentropic compressibility ΔK S , partial molar excess volume V i E , deviation in partial molar isentropic compressibility ΔK S,i , deviation in specific conductivity Δκ have also been estimated and analysed. Spectroscopic properties (IR, 1 H and 13 C NMR) of these mixtures have been investigated in order to understand the structural and interactional behaviour of formulations studied. The magnitude of interactions between the two components increases with addition of number of oxyethylene groups in Tritons and with rise in temperature. Spectroscopic measurements indicate that interactions are mainly taking place through the five member ring of room temperature ionic liquid and six member ring of Tritons.

  6. Real-time transmission electron microscope observation of gold nanoclusters diffusing into silicon at room temperature

    International Nuclear Information System (INIS)

    Ishida, Tadashi; Nakajima, Yuuki; Fujita, Hiroyuki; Endo, Junji; Collard, Dominique

    2009-01-01

    Gold diffusion into silicon at room temperature was observed in real time with atomic resolution. Gold nanoclusters were formed on a silicon surface by an electrical discharge between a silicon tip and a gold coated tip inside an ultrahigh-vacuum transmission electron microscope (TEM) specimen chamber. At the moment of the gold nanocluster deposition, the gold nanoclusters had a crystalline structure. The crystalline structure gradually disappeared due to the interdiffusion between silicon and gold as observed after the deposition of gold nanoclusters. The shape of the nanocluster gradually changed due to the gold diffusion into the damaged silicon. The diffusion front between silicon and gold moved toward the silicon side. From the observations of the diffusion front, the gold diffusivity at room temperature was extracted. The extracted activation energy, 0.21 eV, matched the activation energy in bulk diffusion between damaged silicon and gold. This information is useful for optimizing the hybridization between solid-state and biological nanodevices in which gold is used as an adhesive layer between the two devices.

  7. Characterization of nanostructured Mn3O4 thin films grown by SILAR method at room temperature

    International Nuclear Information System (INIS)

    Ubale, A.U.; Belkhedkar, M.R.; Sakhare, Y.S.; Singh, Arvind; Gurada, Chetan; Kothari, D.C.

    2012-01-01

    A novel successive ionic layer adsorption and reaction method has been successfully employed to grow nanostructured conducting nearly transparent thin films of Mn 3 O 4 on to glass substrates at room temperature using MnCl 2 and NaOH as cationic and anionic precursors. The structural and morphological characterizations of the as deposited Mn 3 O 4 films have been carried out by means of X-ray diffraction (XRD), Field Emission Scanning Electron Micrograph (FESEM), EDAX, Atomic Fore Microscopy (AFM) and Fourier Transform Infrared Spectrum (FTIR) analysis. The optical absorption and electrical resistivity measurements were carried out to investigate optical band gap and activation energy of Mn 3 O 4 films deposited by SILAR method. The optical band gap and activation energy of the as deposited film is found to be 2.70 and 0.14 eV respectively. The thermo-emf measurements of Mn 3 O 4 thin film confirm its p-type semiconducting nature. Highlights: ► Nanostructured Mn 3 O 4 thin film is prepared by SILAR method at room temperature. ► The film is nanocrystalline with orthorhombic structure of Mn 3 O 4 . ► The XRD, FTIR, FESEM, EDX and AFM characterization confirms nanocrystalline nature. ► Optical band gap, electrical resistivity and activation energy of film is reported. ► A thermo-emf measurement confirms p-type conductivity of Mn 3 O 4 films.

  8. Room temperature ferromagnetism in Mn-doped NiO nanoparticles

    Science.gov (United States)

    Layek, Samar; Verma, H. C.

    2016-01-01

    Mn-doped NiO nanoparticles of the series Ni1-xMnxO (x=0.00, 0.02, 0.04 and 0.06) are successfully synthesized using a low temperature hydrothermal method. Samples up to 6% Mn-doping are single phase in nature as observed from powder x-ray diffraction (XRD) studies. Rietveld refinement of the XRD data shows that all the single phase samples crystallize in the NaCl like fcc structure with space group Fm-3m. Unit cell volume decreases with increasing Mn-doping. Pure NiO nanoparticles show weak ferromagnetism, may be due to nanosize nature. Introduction of Mn within NiO lattice improves the magnetic properties significantly. Room temperature ferromagnetism is found in all the doped samples whereas the magnetization is highest for 2% Mn-doping and then decreases with further doping. The ZFC and FC branches in the temperature dependent magnetization separate well above 350 K indicating transition temperature well above room temperature for 2% Mn-doped NiO Nanoparticle. The ferromagnetic Curie temperature is found to be 653 K for the same sample as measured by temperature dependent magnetization study using vibrating sample magnetometer (VSM) in high vacuum.

  9. Room temperature ferromagnetism in Fe-doped CuO nanoparticles.

    Science.gov (United States)

    Layek, Samar; Verma, H C

    2013-03-01

    The pure and Fe-doped CuO nanoparticles of the series Cu(1-x)Fe(x)O (x = 0.00, 0.02, 0.04, 0.06 and 0.08) were successfully prepared by a simple low temperature sol-gel method using metal nitrates and citric acid. Rietveld refinement of the X-ray diffraction data showed that all the samples were single phase crystallized in monoclinic structure of space group C2/c with average crystallite size of about 25 nm and unit cell volume decreases with increasing iron doping concentration. TEM micrograph showed nearly spherical shaped agglomerated particles of 4% Fe-doped CuO with average diameter 26 nm. Pure CuO showed weak ferromagnetic behavior at room temperature with coercive field of 67 Oe. The ferromagnetic properties were greatly enhanced with Fe-doping in the CuO matrix. All the doped samples showed ferromagnetism at room temperature with a noticeable coercive field. Saturation magnetization increases with increasing Fe-doping, becomes highest for 4% doping then decreases for further doping which confirms that the ferromagnetism in these nanoparticles are intrinsic and are not resulting from any impurity phases. The ZFC and FC branches of the temperature dependent magnetization (measured in the range of 10-350 K by SQUID magnetometer) look like typical ferromagnetic nanoparticles and indicates that the ferromagnetic Curie temperature is above 350 K.

  10. Porous aluminum room temperature anodizing process in a fluorinated-oxalic acid solution

    Science.gov (United States)

    Dhahri, S.; Fazio, E.; Barreca, F.; Neri, F.; Ezzaouia, H.

    2016-08-01

    Anodizing of aluminum is used for producing porous insulating films suitable for different applications in electronics and microelectronics. Porous-type aluminum films are most simply realized by galvanostatic anodizing in aqueous acidic solutions. The improvement in application of anodizing technique is associated with a substantial reduction of the anodizing voltage at appropriate current densities as well as to the possibility to carry out the synthesis process at room temperature in order to obtain a self-planarizing dielectric material incorporated in array of super-narrow metal lines. In this work, the anodizing of aluminum to obtain porous oxide was carried out, at room temperature, on three different substrates (glass, stainless steel and aluminum), using an oxalic acid-based electrolyte with the addition of a relatively low amount of 0.4 % of HF. Different surface morphologies, from nearly spherical to larger porous nanostructures with smooth edges, were observed by means of scanning electron microscopy. These evidences are explained by considering the formation, transport and adsorption of the fluorine species which react with the Al3+ ions. The behavior is also influenced by the nature of the original substrate.

  11. Metal-Controlled Magnetoresistance at Room Temperature in Single-Molecule Devices.

    Science.gov (United States)

    Aragonès, Albert C; Aravena, Daniel; Valverde-Muñoz, Francisco J; Real, José Antonio; Sanz, Fausto; Díez-Pérez, Ismael; Ruiz, Eliseo

    2017-04-26

    The appropriate choice of the transition metal complex and metal surface electronic structure opens the possibility to control the spin of the charge carriers through the resulting hybrid molecule/metal spinterface in a single-molecule electrical contact at room temperature. The single-molecule conductance of a Au/molecule/Ni junction can be switched by flipping the magnetization direction of the ferromagnetic electrode. The requirements of the molecule include not just the presence of unpaired electrons: the electronic configuration of the metal center has to provide occupied or empty orbitals that strongly interact with the junction metal electrodes and that are close in energy to their Fermi levels for one of the electronic spins only. The key ingredient for the metal surface is to provide an efficient spin texture induced by the spin-orbit coupling in the topological surface states that results in an efficient spin-dependent interaction with the orbitals of the molecule. The strong magnetoresistance effect found in this kind of single-molecule wire opens a new approach for the design of room-temperature nanoscale devices based on spin-polarized currents controlled at molecular level.

  12. Fatigue behavior of alloy 600 in sodium chloride solution at room temperature

    International Nuclear Information System (INIS)

    Ho, J.-T.; Yu, G.-P.

    2004-01-01

    Fatigue crack growth (FCG) rates of mill annealed Alloy 600 in NaCI solution were studied by a fracture mechanics test method. Compact tension (CT) specimens were tested under load control with a sinusoidal wave form, in accordance with ASTM specification E647-83, to investigate the effects of environment, load frequency (f), load ratio (R=Pmin/Pmax). The FCG rates of Alloy 600, R=0.1, f=1Hz, were quite similar in air, distilled water, and NaCI (0.6 M, 0.1 M, and 0.001 M) solution at room temperature. Environmental enhancement effect on the FCG rate of Alloy 600 was not significant in NaCI solution. Variations of the load frequency (0.03Hz-3Hz) did not influence the FCG rates of Alloy 600 significantly in air and 0.1 M NaCI solution. The FCG rates of Alloy 600 in air and 0.1 M NaCI solution increased with increasing the load ratio. Compared with the corrosion effects, test results showed that the mechanical effects dominated on the FCG rates of Alloy 600 in chloride solution at room temperature. The SEM fractographs showed that significant striations and transgranular fracture modes were observed on tested specimens. (author)

  13. Fabry-Pérot Oscillation and Room Temperature Lasing in Perovskite Cube-Corner Pyramid Cavities

    KAUST Repository

    Mi, Yang; Liu, Zhixiong; Shang, Qiuyu; Niu, Xinxiang; Shi, Jia; Zhang, Shuai; Chen, Jie; Du, Wenna; Wu, Zhiyong; Wang, Rui; Qiu, Xiaohui; Hu, Xiaoyong; Zhang, Qing; Wu, Tao; Liu, Xinfeng

    2018-01-01

    Recently, organometal halide perovskite-based optoelectronics, particularly lasers, have attracted intensive attentions because of its outstanding spectral coherence, low threshold, and wideband tunability. In this work, high-quality CH3 NH3 PbBr3 single crystals with a unique shape of cube-corner pyramids are synthesized on mica substrates using chemical vapor deposition method. These micropyramids naturally form cube-corner cavities, which are eminent candidates for small-sized resonators and retroreflectors. The as-grown perovskites show strong emission ≈530 nm in the vertical direction at room temperature. A special Fabry-Pérot (F-P) mode is employed to interpret the light confinement in the cavity. Lasing from the perovskite pyramids is observed from 80 to 200 K, with threshold ranging from ≈92 µJ cm-2 to 2.2 mJ cm-2 , yielding a characteristic temperature of T0 = 35 K. By coating a thin layer of Ag film, the threshold is reduced from ≈92 to 26 µJ cm-2 , which is accompanied by room temperature lasing with a threshold of ≈75 µJ cm-2 . This work advocates the prospect of shape-engineered perovskite crystals toward developing micro-sized optoelectronic devices and potentially investigating light-matter coupling in quantum optics.

  14. Room-Temperature-Processed Flexible Amorphous InGaZnO Thin Film Transistor.

    Science.gov (United States)

    Xiao, Xiang; Zhang, Letao; Shao, Yang; Zhou, Xiaoliang; He, Hongyu; Zhang, Shengdong

    2017-12-13

    A room-temperature flexible amorphous indium-gallium-zinc oxide thin film transistor (a-IGZO TFT) technology is developed on plastic substrates, in which both the gate dielectric and passivation layers of the TFTs are formed by an anodic oxidation (anodization) technique. While the gate dielectric Al 2 O 3 is grown with a conventional anodization on an Al:Nd gate electrode, the channel passivation layer Al 2 O 3 is formed using a localized anodization technique. The anodized Al 2 O 3 passivation layer shows a superior passivation effect to that of PECVD SiO 2 . The room-temperature-processed flexible a-IGZO TFT exhibits a field-effect mobility of 7.5 cm 2 /V·s, a subthreshold swing of 0.44 V/dec, an on-off ratio of 3.1 × 10 8 , and an acceptable gate-bias stability with threshold voltage shifts of 2.65 and -1.09 V under positive gate-bias stress and negative gate-bias stress, respectively. Bending and fatigue tests confirm that the flexible a-IGZO TFT also has a good mechanical reliability, with electrical performances remaining consistent up to a strain of 0.76% as well as after 1200 cycles of fatigue testing.

  15. Room-temperature InP/InAsP Quantum Discs-in-Nanowire Infrared Photodetectors.

    Science.gov (United States)

    Karimi, Mohammad; Jain, Vishal; Heurlin, Magnus; Nowzari, Ali; Hussain, Laiq; Lindgren, David; Stehr, Jan Eric; Buyanova, Irina A; Gustafsson, Anders; Samuelson, Lars; Borgström, Magnus T; Pettersson, Håkan

    2017-06-14

    The possibility to engineer nanowire heterostructures with large bandgap variations is particularly interesting for technologically important broadband photodetector applications. Here we report on a combined study of design, fabrication, and optoelectronic properties of infrared photodetectors comprising four million n + -i-n + InP nanowires periodically ordered in arrays. The nanowires were grown by metal-organic vapor phase epitaxy on InP substrates, with either a single or 20 InAsP quantum discs embedded in the i-segment. By Zn compensation of the residual n-dopants in the i-segment, the room-temperature dark current is strongly suppressed to a level of pA/NW at 1 V bias. The low dark current is manifested in the spectrally resolved photocurrent measurements, which reveal strong photocurrent contributions from the InAsP quantum discs at room temperature with a threshold wavelength of about 2.0 μm and a bias-tunable responsivity reaching 7 A/W@1.38 μm at 2 V bias. Two different processing schemes were implemented to study the effects of radial self-gating in the nanowires induced by the nanowire/SiO x /ITO wrap-gate geometry. Summarized, our results show that properly designed axial InP/InAsP nanowire heterostructures are promising candidates for broadband photodetectors.

  16. Room-temperature annealing of Si implantation damage in InP

    International Nuclear Information System (INIS)

    Akano, U.G.; Mitchell, I.V.

    1991-01-01

    Spontaneous recovery at 295 K of Si implant damage in InP is reported. InP(Zn) and InP(S) wafers of (100) orientation have been implanted at room temperature with 600 keV Si + ions to doses ranging from 3.6x10 11 to 2x10 14 cm -2 . Room-temperature annealing of the resultant damage has been monitored by the Rutherford backscattering/channeling technique. For Si doses ≤4x10 13 cm -2 , up to 70% of the initial damage (displaced atoms) annealed out over a period of ∼85 days. The degree of recovery was found to depend on the initial level of damage. Recovery is characterized by at least two time constants t 1 2 ∼100 days. Anneal rates observed between 295 and 375 K are consistent with an activation energy of 1.2 eV, suggesting that the migration of implant-induced vacancies is associated with the reordering of the InP lattice

  17. A novel perovskite oxide chemically designed to show multiferroic phase boundary with room-temperature magnetoelectricity

    Science.gov (United States)

    Fernández-Posada, Carmen M.; Castro, Alicia; Kiat, Jean-Michel; Porcher, Florence; Peña, Octavio; Algueró, Miguel; Amorín, Harvey

    2016-09-01

    There is a growing activity in the search of novel single-phase multiferroics that could finally provide distinctive magnetoelectric responses at room temperature, for they would enable a range of potentially disruptive technologies, making use of the ability of controlling polarization with a magnetic field or magnetism with an electric one (for example, voltage-tunable spintronic devices, uncooled magnetic sensors and the long-searched magnetoelectric memory). A very promising novel material concept could be to make use of phase-change phenomena at structural instabilities of a multiferroic state. Indeed, large phase-change magnetoelectric response has been anticipated by a first-principles investigation of the perovskite BiFeO3-BiCoO3 solid solution, specifically at its morphotropic phase boundary between multiferroic polymorphs of rhombohedral and tetragonal symmetries. Here, we report a novel perovskite oxide that belongs to the BiFeO3-BiMnO3-PbTiO3 ternary system, chemically designed to present such multiferroic phase boundary with enhanced ferroelectricity and canted ferromagnetism, which shows distinctive room-temperature magnetoelectric responses.

  18. Room temperature solution processed low dimensional CH3NH3PbI3 NIR detector

    Science.gov (United States)

    Besra, N.; Paul, T.; Sarkar, P. K.; Thakur, S.; Sarkar, S.; Das, A.; Chanda, K.; Sardar, K.; Chattopadhyay, K. K.

    2018-05-01

    Metal halide perovskites have recently drawn immense research interests among the worldwide scientific community due to their excellent light harvesting capabilities and above all, cost effectiveness. These new class of materials have already been used as efficient optoelectronic devices e.g. solar cells, photo detectors, etc. Here in this work, room temperature NIR (near infra red) response of organic-inorganic lead halide perovskite CH3NH3PbI3 (Methylammonium lead tri iodide) nanorods has been studied. A very simple solution process technique has been adopted to synthesize CH3NH3PbI3 nanostructures at room temperature. The NIR exposure upon the sample resulted in a considerable hike in its dark current with very good responsivity (0.37 mA/W). Along with that, a good on-off ratio (41.8) was also obtained when the sample was treated under a pulsed NIR exposure with operating voltage of 2 V. The specific detectivity of the device came in the order of 1010 Jone.

  19. A Novel Lipid Extraction Method from Wet Microalga Picochlorum sp. at Room Temperature

    Directory of Open Access Journals (Sweden)

    Fangfang Yang

    2014-03-01

    Full Text Available A novel method using ethanol was proposed for extracting lipids from wet microalga Picochlorum sp. at room temperature and pressure. In this study, Central Composite design (CCD was applied to investigate the optimum conditions of lipid extraction. The results revealed that the solvent to biomass ratio had the largest effect on lipid extraction efficiency, followed by extraction time and temperature. A high lipid extraction yield (33.04% of the dry weight was obtained under the following extraction conditions: 5 mL solvents per gram of wet biomass for 37 min with gentle stirring at room temperature. The extraction yield was comparable to that obtained by the widely used Bligh-Dyer method. Furthermore, no significant differences in the distribution of lipid classes and fatty acid composition were observed according to different extraction methods. In conclusion, these results indicated that the proposed procedure using ethanol could extract lipids from wet biomass efficiently and had giant potential for lipid extraction at large scale.

  20. Quantum Correlations of Light from a Room-Temperature Mechanical Oscillator

    Science.gov (United States)

    Sudhir, V.; Schilling, R.; Fedorov, S. A.; Schütz, H.; Wilson, D. J.; Kippenberg, T. J.

    2017-07-01

    When an optical field is reflected from a compliant mirror, its intensity and phase become quantum-correlated due to radiation pressure. These correlations form a valuable resource: the mirror may be viewed as an effective Kerr medium generating squeezed states of light, or the correlations may be used to erase backaction from an interferometric measurement of the mirror's position. To date, optomechanical quantum correlations have been observed in only a handful of cryogenic experiments, owing to the challenge of distilling them from thermomechanical noise. Accessing them at room temperature, however, would significantly extend their practical impact, with applications ranging from gravitational wave detection to chip-scale accelerometry. Here, we observe broadband quantum correlations developed in an optical field due to its interaction with a room-temperature nanomechanical oscillator, taking advantage of its high-cooperativity near-field coupling to an optical microcavity. The correlations manifest as a reduction in the fluctuations of a rotated quadrature of the field, in a frequency window spanning more than an octave below mechanical resonance. This is due to coherent cancellation of the two sources of quantum noise contaminating the measured quadrature—backaction and imprecision. Supplanting the backaction force with an off-resonant test force, we demonstrate the working principle behind a quantum-enhanced "variational" force measurement.

  1. Defects related room temperature ferromagnetism in Cu-implanted ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Li, D.; Li, D.K.; Wu, H.Z.; Liang, F.; Xie, W.; Zou, C.W.; Shao, L.X.

    2014-01-01

    Highlights: • Room temperature ferromagnetism was observed in Cu-implanted ZnO nanorod arrays. • Cu-implanted ZnO nanorods show a saturation magnetization value of 1.82 μ B /Cu. • The origin of ferromagnetism can be explained by the defects related bound magnetic polarons. -- Abstract: Room temperature ferromagnetism (FM) was observed in Cu-implanted ZnO nanorod arrays. The implantation dose for Cu ions was 1 × 10 16 cm −2 and the implantation energy was 100 keV. The ion implantation induced defects and disorder has been observed by the XRD, PL and TEM experiments. The PL spectrum revealed a dominant luminescence peaks at 390 nm and a broad and strong green emission at 500–700 nm, which is considered to be related to the ionized oxygen vacancy. Cu-implanted ZnO nanorods annealed at 500 °C show a saturation magnetization value of 1.82 μ B /Cu and a positive coercive field of 68 Oe. The carrier concentration is not much improved after annealing and in the order of 10 16 cm −3 , which suggests that FM does not depend upon the presence of a significant carrier concentration. The origin of ferromagnetism behavior can be explained on the basis of electrons and defects that form bound magnetic polarons, which overlap to create a spin-split impurity band

  2. Effects of different oxyanions in solution on the precipitation of jarosite at room temperature.

    Science.gov (United States)

    Yeongkyoo, Kim

    2018-04-09

    The effects of five different oxyanions, AsO 4 , SeO 3 , SeO 4 , MoO 4 , and CrO 4 , on the precipitation of jarosite at room temperature were investigated by X-ray diffraction, scanning electron microscopy, and chemical analysis. Different amounts (2, 5, and 10 mol%) of oxyanions in the starting solution and different aging times (1 h-40 days) were used for the experiment. In the initial stage, only the amorphous phase appears for all samples. With increasing aging time, jarosite and jarosite with oxyanions start precipitating at room temperature with different precipitation rates and crystallinities. Jarosite with AsO 4 shows the lowest precipitation rate and lowest crystallinity. With increasing amounts of oxyanions, the crystallization rate decreases, especially for jarosite with AsO 4 . The jarosite samples with CrO 4 and SeO 4 show the fastest precipitation and highest crystallinities. For the jarosite samples with a low precipitation rate and low crystallinity, the amorphous phase contains high concentrations of oxyanions, probably because of the fast precipitation of the amorphous iron oxyanion phase; however, the phase with fast jarosite precipitation contains fewer oxyanions. The results show that coprecipitation of jarosite can play a more important role in controlling the behavior of CrO 4 than AsO 4 in acid mine drainage. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. A Room Temperature Ultrasensitive Magnetoelectric Susceptometer for Quantitative Tissue Iron Detection

    Science.gov (United States)

    Xi, Hao; Qian, Xiaoshi; Lu, Meng-Chien; Mei, Lei; Rupprecht, Sebastian; Yang, Qing X.; Zhang, Q. M.

    2016-07-01

    Iron is a trace mineral that plays a vital role in the human body. However, absorbing and accumulating excessive iron in body organs (iron overload) can damage or even destroy an organ. Even after many decades of research, progress on the development of noninvasive and low-cost tissue iron detection methods is very limited. Here we report a recent advance in a room-temperature ultrasensitive biomagnetic susceptometer for quantitative tissue iron detection. The biomagnetic susceptometer exploits recent advances in the magnetoelectric (ME) composite sensors that exhibit an ultrahigh AC magnetic sensitivity under the presence of a strong DC magnetic field. The first order gradiometer based on piezoelectric and magnetostrictive laminate (ME composite) structure shows an equivalent magnetic noise of 0.99 nT/rt Hz at 1 Hz in the presence of a DC magnetic field of 0.1 Tesla and a great common mode noise rejection ability. A prototype magnetoelectric liver susceptometry has been demonstrated with liver phantoms. The results indicate its output signals to be linearly responsive to iron concentrations from normal iron dose (0.05 mg Fe/g liver phantom) to 5 mg Fe/g liver phantom iron overload (100X overdose). The results here open up many innovative possibilities for compact-size, portable, cost-affordable, and room-temperature operated medical systems for quantitative determinations of tissue iron.

  4. Alcohols react with MCM-41 at room temperature and chemically modify mesoporous silica.

    Science.gov (United States)

    Björklund, Sebastian; Kocherbitov, Vitaly

    2017-08-30

    Mesoporous silica has received much attention due to its well-defined structural order, high surface area, and tunable pore diameter. To successfully employ mesoporous silica for nanotechnology applications it is important to consider how it is influenced by solvent molecules due to the fact that most preparation procedures involve treatment in various solvents. In the present work we contribute to this important topic with new results on how MCM-41 is affected by a simple treatment in alcohol at room temperature. The effects of alcohol treatment are characterized by TGA, FTIR, and sorption calorimetry. The results are clear and show that treatment of MCM-41 in methanol, ethanol, propanol, butanol, pentanol, or octanol at room temperature introduces alkoxy groups that are covalently bound to the silica surface. It is shown that alcohol treated MCM-41 becomes more hydrophobic and that this effect is sequentially more prominent going from methanol to octanol. Chemical formation of alkoxy groups onto MCM-41 occurs both for calcined and hydroxylated MCM-41 and the alkoxy groups are hydrolytically unstable and can be replaced by silanol groups after exposure to water. The results are highly relevant for mesoporous silica applications that involve contact or treatment in protic solvents, which is very common.

  5. Single molecule dynamics at a mechanically controllable break junction in solution at room temperature.

    Science.gov (United States)

    Konishi, Tatsuya; Kiguchi, Manabu; Takase, Mai; Nagasawa, Fumika; Nabika, Hideki; Ikeda, Katsuyoshi; Uosaki, Kohei; Ueno, Kosei; Misawa, Hiroaki; Murakoshi, Kei

    2013-01-23

    The in situ observation of geometrical and electronic structural dynamics of a single molecule junction is critically important in order to further progress in molecular electronics. Observations of single molecular junctions are difficult, however, because of sensitivity limits. Here, we report surface-enhanced Raman scattering (SERS) of a single 4,4'-bipyridine molecule under conditions of in situ current flow in a nanogap, by using nano-fabricated, mechanically controllable break junction (MCBJ) electrodes. When adsorbed at room temperature on metal nanoelectrodes in solution to form a single molecule junction, statistical analysis showed that nontotally symmetric b(1) and b(2) modes of 4,4'-bipyridine were strongly enhanced relative to observations of the same modes in solid or aqueous solutions. Significant changes in SERS intensity, energy (wavenumber), and selectivity of Raman vibrational bands that are coincident with current fluctuations provide information on distinct states of electronic and geometrical structure of the single molecule junction, even under large thermal fluctuations occurring at room temperature. We observed the dynamics of 4,4'-bipyridine motion between vertical and tilting configurations in the Au nanogap via b(1) and b(2) mode switching. A slight increase in the tilting angle of the molecule was also observed by noting the increase in the energies of Raman modes and the decrease in conductance of the molecular junction.

  6. Room temperature high-detectivity mid-infrared photodetectors based on black arsenic phosphorus.

    Science.gov (United States)

    Long, Mingsheng; Gao, Anyuan; Wang, Peng; Xia, Hui; Ott, Claudia; Pan, Chen; Fu, Yajun; Liu, Erfu; Chen, Xiaoshuang; Lu, Wei; Nilges, Tom; Xu, Jianbin; Wang, Xiaomu; Hu, Weida; Miao, Feng

    2017-06-01

    The mid-infrared (MIR) spectral range, pertaining to important applications, such as molecular "fingerprint" imaging, remote sensing, free space telecommunication, and optical radar, is of particular scientific interest and technological importance. However, state-of-the-art materials for MIR detection are limited by intrinsic noise and inconvenient fabrication processes, resulting in high-cost photodetectors requiring cryogenic operation. We report black arsenic phosphorus-based long-wavelength IR photodetectors, with room temperature operation up to 8.2 μm, entering the second MIR atmospheric transmission window. Combined with a van der Waals heterojunction, room temperature-specific detectivity higher than 4.9 × 10 9 Jones was obtained in the 3- to 5-μm range. The photodetector works in a zero-bias photovoltaic mode, enabling fast photoresponse and low dark noise. Our van der Waals heterojunction photodetectors not only exemplify black arsenic phosphorus as a promising candidate for MIR optoelectronic applications but also pave the way for a general strategy to suppress 1/ f noise in photonic devices.

  7. Structure of C60: Partial orientational order in the room-temperature modification of C60

    International Nuclear Information System (INIS)

    Buergi, H.B.; Restori, R.; Schwarzenbach, D.

    1993-01-01

    Using published synchrotron X-ray data, the room-temperature scattering density distribution of pure C 60 has been parametrized in terms of a combination of eight oriented symmetry-related images of the molecule, and of a freely spinning molecule. Corresponding populations are 61 and 39%. The oriented part of the model is obtained, in good approximation, by imposing m anti 3m symmetry on the energetically more favourable major orientation in the low-temperature structure of C 60 . The model was refined using angle restraints to impose the icosahedral molecular symmetry and displacement-factor restraints to restrict thermal movements to rigid-body translations and librations. Translational displacement factors are in the range 0.017-0.023 A 2 . The orientational probability density distribution obtained from the model shows maxima for C 60 orientations possessing anti 3m crystallographic site symmetry. It is also relatively large for the C 60 orientations with cubic site symmetry m anti 3. The smallest energy barrier for reorientation between different anti 3m orientations via an m anti 3 orientation appears to be less than 2 kJ mol -1 . On average, 75% of the intermolecular contacts of the oriented molecules are longer than those observed in the low-temperature structure, the other 25% are less favourable. The second orientation of C 60 found in the low-temperature structure could not be identified at room temperature. (orig.)

  8. Room temperature diamond-like carbon coatings produced by low energy ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Markwitz, A., E-mail: a.markwitz@gns.cri.nz [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Mohr, B.; Leveneur, J. [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand)

    2014-07-15

    Nanometre-smooth diamond-like carbon coatings (DLC) were produced at room temperature with ion implantation using 6 kV C{sub 3}H{sub y}{sup +} ion beams. Ion beam analysis measurements showed that the coatings contain no heavy Z impurities at the level of 100 ppm, have a homogeneous stoichiometry in depth and a hydrogen concentration of typically 25 at.%. High resolution TEM analysis showed high quality and atomically flat amorphous coatings on wafer silicon. Combined TEM and RBS analysis gave a coating density of 3.25 g cm{sup −3}. Raman spectroscopy was performed to probe for sp{sup 2}/sp{sup 3} bonds in the coatings. The results indicate that low energy ion implantation with 6 kV produces hydrogenated amorphous carbon coatings with a sp{sup 3} content of about 20%. Results highlight the opportunity of developing room temperature DLC coatings with ion beam technology for industrial applications.

  9. Complex temperature dependence of coupling and dissipation of cavity magnon polaritons from millikelvin to room temperature

    Science.gov (United States)

    Boventer, Isabella; Pfirrmann, Marco; Krause, Julius; Schön, Yannick; Kläui, Mathias; Weides, Martin

    2018-05-01

    Hybridized magnonic-photonic systems are key components for future information processing technologies such as storage, manipulation, or conversion of data both in the classical (mostly at room temperature) and quantum (cryogenic) regime. In this work, we investigate a yttrium-iron-garnet sphere coupled strongly to a microwave cavity over the full temperature range from 290 K to 30 mK . The cavity-magnon polaritons are studied from the classical to the quantum regimes where the thermal energy is less than one resonant microwave quanta, i.e., at temperatures below 1 K . We compare the temperature dependence of the coupling strength geff(T ) , describing the strength of coherent energy exchange between spin ensemble and cavity photon, to the temperature behavior of the saturation magnetization evolution Ms(T ) and find strong deviations at low temperatures. The temperature dependence of magnonic disspation is governed at intermediate temperatures by rare-earth impurity scattering leading to a strong peak at 40 K . The linewidth κm decreases to 1.2 MHz at 30 mK , making this system suitable as a building block for quantum electrodynamics experiments. We achieve an electromagnonic cooperativity in excess of 20 over the entire temperature range, with values beyond 100 in the millikelvin regime as well as at room temperature. With our measurements, spectroscopy on strongly coupled magnon-photon systems is demonstrated as versatile tool for spin material studies over large temperature ranges. Key parameters are provided in a single measurement, thus simplifying investigations significantly.

  10. Room temperature deformation of in-situ grown quasicrystals embedded in Al-based cast alloy

    Directory of Open Access Journals (Sweden)

    Boštjan Markoli

    2013-12-01

    Full Text Available An Al-based cast alloy containing Mn, Be and Cu has been chosen to investigate the room temperature deformation behavior of QC particles embedded in Al-matrix. Using LOM, SEM (equipped with EDS, conventional TEM with SAED and controlled tensile and compression tests, the deformation response of AlMn2Be2Cu2 cast alloy at room temperature has been examined. Alloy consisted of Al-based matrix, primary particles and eutectic icosahedral quasicrystalline (QC i-phase and traces of Θ-Al2Cu and Al10Mn3. Tensile and compression specimens were used for evaluation of mechanical response and behavior of QC i-phase articles embedded in Al-cast alloy. It has been established that embedded QC i-phase particles undergo plastic deformation along with the Al-based matrix even under severe deformation and have the response resembling that of the metallic materials by formation of typical cup-and-cone feature prior to failure. So, we can conclude that QC i-phase has the ability to undergo plastic deformation along with the Al-matrix to greater extent contrary to e.g. intermetallics such as Θ-Al2Cu for instance.

  11. Cellulose gels produced in room temperature ionic liquids by ionizing radiation

    International Nuclear Information System (INIS)

    Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

    2014-01-01

    Cellulose-based gels were produced in room temperature ionic liquids (RTILs) by ionizing radiation. Cellulose was dissolved at the initial concentration of 20 wt% in 1-ethyl-3-methylimidazolium (EMI)-acetate or N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEMA)-formate with a water content of 18 wt%, and irradiated with γ-rays under aerated condition to produce new cellulose gels. The gel fractions of the cellulose gels obtained in EMI-acetate and DEMA-formate at a dose of 10 kGy were 13% and 19%, respectively. The formation of gel fractions was found to depend on the initial concentration of cellulose, water content, and irradiation temperature. The obtained gel readily absorbed water, methanol, ethanol, dichloromethane, N,N-dimethylacetamide, and RTILs. - Highlights: • Cellulose gels were produced in room temperature ionic liquids (RTILs). • Water plays a crucial role in the cross-linking reaction. • Cellulose gels swollen with RTILs show good electronic conductivity (3.0 mS cm −1 )

  12. Low cycle fatigue strength of some austenitic stainless steels at room temperature and elevated temperatures

    International Nuclear Information System (INIS)

    Type 304, 316, and 316L stainless steels were tested from room temperature to 650 0 C using two kinds of bending test specimens. Particularly, Type 304 was tested at several cyclic rates and 550 0 and 650 0 C, and the effect of cyclic rate on its fatigue strength was investigated. Test results are summarized as follows: (1) The bending fatigue strength at room temperature test shows good agreement with the axial fatigue one, (2) Manson--Coffin's fatigue equation can be applied to the results, (3) the ratio of crack initiation to failure life becomes larger at higher stress level, and (4) the relation between crack propagation life and total strain range or elastic strain range are linear in log-log scale. This relation also agrees with the equations which were derived from some crack propagation laws. It was also observed at the elevated temperature test: (1) The reduction of fatigue strength is not noticeable below 500 0 C, but it is noted at higher temperature. (2) The cycle rate does not affect on fatigue strength in faster cyclic rate than 20 cpm and below 100,000 cycles life range. (3) Type 316 stainless steel shows better fatigue property than type 304 and 316L stainless steels. 30 figures

  13. CL 14: Solvation structure and dynamics of room temperature ionic liquids

    International Nuclear Information System (INIS)

    Musat, Raluca M.; Polyansky, Dmitriy; Crowell, Robert A.; Thomas, Marie; Wishart, James F.; Takahashi, Kenji; Katsumura, Yosuke

    2010-01-01

    Room temperature ionic liquids (RTILs) have emerged as a new class of solvents that, due to their unique properties (e.g., low volatility, large electrochemical window, high conductivity, etc.), have several potential applications. Among these are their possible use in nuclear fuel reprocessing, dye sensitized solar cells, and CO 2 sequestration. The properties of a given class of RTILs depend strongly on the choice of the counter anion. In this contribution we present new results using both static and time-resolved EXAFS (ca. 1 ns resolution) and time resolved optical absorption spectroscopy on a series of bromide containing imidazolium salts. The static results provide detailed information of the solvation shell of the bromide ion while the time-resolved data shed light on the nature and chemical behavior of the lowest lying charge transfer band, the physical motion of the bromine atom and its conversion to di-bromide. The photochemistry of the charge transfer (CT) band of the room temperature ionic liquid 1-hexyl-3-methylimidazolium bromide is investigated using ultrafast transient absorption spectroscopy (TA) in the near-IR and steady state UV absorption. Irradiation of the CT band at 266 nm results in the steady state production of di-bromide which absorbs strongly at 266 nm. It is shown that this photoproduct, which is apparently very stable, adversely affects ultrafast transient absorption measurements. Flowing and simultaneously translating the sample mitigates this effect and reveals new transient species and dynamics within the detection window of 850 nm to 1250 nm. (authors)

  14. Room temperature ammonia and VOC sensing properties of CuO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Bhuvaneshwari, S.; Gopalakrishnan, N., E-mail: ngk@nitt.edu [Thin film laboratory, National Institute of Technology, Tiruchirappalli-620015 (India)

    2016-05-23

    Here, we report a NH{sub 3} and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

  15. Room temperature creep behavior of Ti–Nb–Ta–Zr–O alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei-dong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Liu, Yong, E-mail: yonliu@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Wu, Hong; Lan, Xiao-dong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Qiu, Jingwen [College of Electrical and Mechanical Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201 (China); Hu, Te [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Tang, Hui-ping [State Key Laboratory of Porous Metal Materials, Northwestern Institute of Nonferrous Metal Research, Xi' an, Shaanxi 710012 (China)

    2016-08-15

    The room temperature creep behavior and deformation mechanisms of a Ti–Nb–Ta–Zr–O alloy, which is also called “gum metal”, were investigated with the nanoindentation creep and conventional creep tests. The microstructure was observed with electron backscattered diffraction analysis (EBSD) and transmission electron microscopy (TEM). The results show that the creep stress exponent of the alloy is sensitive to cold deformation history of the alloy. The alloy which was cold swaged by 85% shows high creep resistance and the stress exponent is approximately equal to 1. Microstructural observation shows that creep process of the alloy without cold deformation is controlled by dislocation mechanism. The stress-induced α' martensitic phase transformation also occurs. The EBSD results show that the grain orientation changes after the creep tests, and thus, the creep of the cold-worked alloy is dominated by the shear deformation of giant faults without direct assistance from dislocations. - Highlights: •Nanoindentation was used to investigate room temperature creep behavior of gum metal. •The creep stress exponent of gum metal is sensitive to the cold deformation history. •The creep stress exponent of cold worked gum metal is approximately equal to 1. •The creep of the cold-worked gum metal is governed by the shear deformation of giant faults.

  16. Fabry-Pérot Oscillation and Room Temperature Lasing in Perovskite Cube-Corner Pyramid Cavities

    KAUST Repository

    Mi, Yang

    2018-01-10

    Recently, organometal halide perovskite-based optoelectronics, particularly lasers, have attracted intensive attentions because of its outstanding spectral coherence, low threshold, and wideband tunability. In this work, high-quality CH3 NH3 PbBr3 single crystals with a unique shape of cube-corner pyramids are synthesized on mica substrates using chemical vapor deposition method. These micropyramids naturally form cube-corner cavities, which are eminent candidates for small-sized resonators and retroreflectors. The as-grown perovskites show strong emission ≈530 nm in the vertical direction at room temperature. A special Fabry-Pérot (F-P) mode is employed to interpret the light confinement in the cavity. Lasing from the perovskite pyramids is observed from 80 to 200 K, with threshold ranging from ≈92 µJ cm-2 to 2.2 mJ cm-2 , yielding a characteristic temperature of T0 = 35 K. By coating a thin layer of Ag film, the threshold is reduced from ≈92 to 26 µJ cm-2 , which is accompanied by room temperature lasing with a threshold of ≈75 µJ cm-2 . This work advocates the prospect of shape-engineered perovskite crystals toward developing micro-sized optoelectronic devices and potentially investigating light-matter coupling in quantum optics.

  17. Radiation damage in room-temperature data acquisition with the PILATUS 6M pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Rajendran, Chitra, E-mail: chitra.rajendran@psi.ch; Dworkowski, Florian S. N.; Wang, Meitian; Schulze-Briese, Clemens [Swiss Light Source at Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

    2011-05-01

    Observations of the dose-rate effect in continuous X-ray diffraction data acquisition at room temperature are presented. The first study of room-temperature macromolecular crystallography data acquisition with a silicon pixel detector is presented, where the data are collected in continuous sample rotation mode, with millisecond read-out time and no read-out noise. Several successive datasets were collected sequentially from single test crystals of thaumatin and insulin. The dose rate ranged between ∼1320 Gy s{sup −1} and ∼8420 Gy s{sup −1} with corresponding frame rates between 1.565 Hz and 12.5 Hz. The data were analysed for global radiation damage. A previously unreported negative dose-rate effect is observed in the indicators of global radiation damage, which showed an approximately 75% decrease in D{sub 1/2} at sixfold higher dose rate. The integrated intensity decreases in an exponential manner. Sample heating that could give rise to the enhanced radiation sensitivity at higher dose rate is investigated by collecting data between crystal temperatures of 298 K and 353 K. UV-Vis spectroscopy is used to demonstrate that disulfide radicals and trapped electrons do not accumulate at high dose rates in continuous data collection.

  18. Study of geometries of active magnetic regenerators for room temperature magnetocaloric refrigeration

    DEFF Research Database (Denmark)

    Lei, Tian; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein

    2017-01-01

    Room temperature magnetic refrigeration has attracted substantial attention during the past decades and continuing to increase the performance of active magnetic regenerators (AMR) is of great interest. Optimizing the regenerator geometry and related operating parameters is a practical and effect......Room temperature magnetic refrigeration has attracted substantial attention during the past decades and continuing to increase the performance of active magnetic regenerators (AMR) is of great interest. Optimizing the regenerator geometry and related operating parameters is a practical...... and effective way to obtain the desired cooling performance. To investigate how to choose and optimize the AMR geometry, a quantitative study is presented by simulations based on a one-dimensional (1D) numerical model. Correlations for calculating the friction factor and heat transfer coefficient are reviewed...... and chosen for modeling different geometries. Moreover, the simulated impacts of various parameters on the regenerator efficiency with a constant specific cooling capacity are presented. An analysis based on entropy production minimization reveals how those parameters affect the main losses occurring inside...

  19. Hydrogen Treatment for Superparamagnetic VO2 Nanowires with Large Room-Temperature Magnetoresistance.

    Science.gov (United States)

    Li, Zejun; Guo, Yuqiao; Hu, Zhenpeng; Su, Jihu; Zhao, Jiyin; Wu, Junchi; Wu, Jiajing; Zhao, Yingcheng; Wu, Changzheng; Xie, Yi

    2016-07-04

    One-dimensional (1D) transition metal oxide (TMO) nanostructures are actively pursued in spintronic devices owing to their nontrivial d electron magnetism and confined electron transport pathways. However, for TMOs, the realization of 1D structures with long-range magnetic order to achieve a sensitive magnetoelectric response near room temperature has been a longstanding challenge. Herein, we exploit a chemical hydric effect to regulate the spin structure of 1D V-V atomic chains in monoclinic VO2 nanowires. Hydrogen treatment introduced V(3+) (3d(2) ) ions into the 1D zigzag V-V chains, triggering the formation of ferromagnetically coupled V(3+) -V(4+) dimers to produce 1D superparamagnetic chains and achieve large room-temperature negative magnetoresistance (-23.9 %, 300 K, 0.5 T). This approach offers new opportunities to regulate the spin structure of 1D nanostructures to control the intrinsic magnetoelectric properties of spintronic materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Observation of Room-Temperature Magnetoresistance in Monolayer MoS2 by Ferromagnetic Gating.

    Science.gov (United States)

    Jie, Wenjing; Yang, Zhibin; Zhang, Fan; Bai, Gongxun; Leung, Chi Wah; Hao, Jianhua

    2017-07-25

    Room-temperature magnetoresistance (MR) effect is observed in heterostructures of wafer-scale MoS 2 layers and ferromagnetic dielectric CoFe 2 O 4 (CFO) thin films. Through the ferromagnetic gating, an MR ratio of -12.7% is experimentally achieved in monolayer MoS 2 under 90 kOe magnetic field at room temperature (RT). The observed MR ratio is much higher than that in previously reported nonmagnetic metal coupled with ferromagnetic insulator, which generally exhibited MR ratio of less than 1%. The enhanced MR is attributed to the spin accumulation at the heterostructure interface and spin injection to the MoS 2 layers by the strong spin-orbit coupling effect. The injected spin can contribute to the spin current and give rise to the MR by changing the resistance of MoS 2 layers. Furthermore, the MR effect decreases as the thickness of MoS 2 increases, and the MR ratio becomes negligible in MoS 2 with thickness more than 10 layers. Besides, it is interesting to find a magnetic field direction dependent spin Hall magnetoresistance that stems from a combination of the spin Hall and the inverse spin Hall effects. Our research provides an insight into exploring RT MR in monolayer materials, which should be helpful for developing ultrathin magnetic storage devices in the atomically thin limit.