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Sample records for room temperature compression

  1. 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

  2. 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.

  3. 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.

  4. Deformation micro-mechanism for compression of magnesium alloys at room temperature analyzed by electron backscatter diffraction

    International Nuclear Information System (INIS)

    Song, G.S.; Chen, Q.Q.; Zhang, S.H.; Xu, Y.

    2015-01-01

    Highlights: • In-situ tracking on the evolution of grains orientation of magnesium alloy was carried out by EBSD. • Distributions of twin bands were closely related to the activation of extension twin variants. • Activation of extension twin significantly changes the order of Schmid factor of slips. • Pyramidal slips become the dominant deformation mode at the late stage of compression. - Abstract: In-situ tracking on the evolution of grains orientation of rolled magnesium alloy sheets compressed uniaxially at room temperature was carried out by the method of electron backscatter diffraction (EBSD), and meanwhile, distributions of twin bands, activations of twin and slips were also analyzed. The results show that the distributions of twin bands were closely related to the activation of extension twin variants. The activation of extension twin significantly changes the order of Schmid factor of different slips, and accordingly affects the activation of slips during the subsequent deformation

  5. Deformation of depleted uranium - 0.78 Ti under shock compression to 11.0 GPa at room temperature

    International Nuclear Information System (INIS)

    Dandekar, D.P.; Martin, A.G.; Kelley, J.V.

    1980-01-01

    The present work on depleted uranium alloyed with 0.78% titanium by weight (i.e., U-0.8 Ti) describes the nature of deformation it undergoes when subjected to shock compression at room temperature. The principal results emerging out of the present work are: (1) The stress limits of elastic deformation are dependent on the thickness of U-0.8Ti. The stress limit decreases from over 3.0 GPa at the impact surface to 1.2 GPa at a depth of 9 mm in U-0.8 Ti; (2) The lower limit of the stress agrees with the static yield stress in U-0.8 Ti; (3) Above the elastic stress limit, the deformation of U-0.8 Ti proceeds in a manner of the ideal plastic solid; and (4) The pressure derivative of Lame's parameter of U-0.8 Ti is estimated to be 3.8

  6. 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

  7. 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 ...

  8. 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)

  9. 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

  10. 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...

  11. 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

  12. 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.

  13. 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...

  14. 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.

  15. 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....

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. Calculation of Vertical Temperature Gradients in Heated Rooms

    DEFF Research Database (Denmark)

    Overby, H.; Steen-Thøde, Mogens

    This paper deals with a simple model which predicts the vertical temperature gradient in a heated room. The gradient is calculated from a dimensionless temperature profile which is determined by two room air temperatures only, the mean temperature in the occupied zone and the mean temperature...

  6. 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

  7. 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

  8. 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

  9. Dynamic Uniaxial Compression of HSLA-65 Steel at Elevated Temperatures

    Science.gov (United States)

    Dike, Shweta; Wang, Tianxue; Zuanetti, Bryan; Prakash, Vikas

    2017-12-01

    In the present study, the dynamic response of a high-strength, low alloy Grade 65 (HSLA-65) steel, used by the United States Navy for ship hull construction, is investigated under dynamic uniaxial compression at temperatures ranging from room temperature to 1000 °C using a novel elevated temperature split-Hopkinson pressure bar. These experiments are designed to probe the dynamic response of HSLA-65 steel in its single α-ferrite phase, mixed α + γ-austenite phase, and the single γ-austenite phase, as a function of temperature. The investigation is conducted at two different average strain rates—1450 and 2100/s. The experimental results indicate that at test temperatures in the range from room temperature to lower than 600 °C, i.e. prior to the development of the mixed α + γ phase, a net softening in flow strength is observed at all levels of plastic strain with increase in test temperatures. As the test temperatures are increased, the rate of this strain softening with temperature is observed to decrease, and at 600 °C the trend reverses itself resulting in an increase in flow stress at all strains tested. This increase in flow stress is understood be due to dynamic strain aging, where solute atoms play a distinctive role in hindering dislocation motion. At 800 °C, a (sharp) drop in the flow stress, equivalent to one-half of its value at room temperature, is observed. As the test temperature are increased to 900 and 1000 °C, further drop in flow stress are observed at all plastic strain levels. In addition, strain hardening in flow stress is observed at all test temperatures up to 600 °C; beyond 800 °C the rate of strain hardening is observed to decrease, with strain softening becoming dominant at temperatures of 900 °C and higher. Moreover, comparing the high strain rate stress versus strain data gathered on HSLA 65 in the current investigation with those available in the literature at quasi-static strain rates, strain-rate hardening can be

  10. 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.

  11. 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

  12. Optimal Chest Compression Rate and Compression to Ventilation Ratio in Delivery Room Resuscitation: Evidence from Newborn Piglets and Neonatal Manikins

    OpenAIRE

    Solev?g, Anne Lee; Schm?lzer, Georg M.

    2017-01-01

    Cardiopulmonary resuscitation (CPR) duration until return of spontaneous circulation (ROSC) influences survival and neurologic outcomes after delivery room (DR) CPR. High quality chest compressions (CC) improve cerebral and myocardial perfusion. Improved myocardial perfusion increases the likelihood of a faster ROSC. Thus, optimizing CC quality may improve outcomes both by preserving cerebral blood flow during CPR and by reducing the recovery time. CC quality is determined by rate, CC to vent...

  13. Dynamic High-Temperature Characterization of an Iridium Alloy in Compression at High Strain Rates

    Energy Technology Data Exchange (ETDEWEB)

    Song, Bo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Experimental Environment Simulation Dept.; Nelson, Kevin [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials Dept.; Lipinski, Ronald J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Fuel Cycle Technology Dept.; Bignell, John L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Structural and Thermal Analysis Dept.; Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Radioisotope Power Systems Program; George, E. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Radioisotope Power Systems Program

    2014-06-01

    Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-temperature high-strain-rate performance are needed for understanding high-speed impacts in severe elevated-temperature environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain-rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. Current high-temperature Kolsky compression bar techniques are not capable of obtaining satisfactory high-temperature high-strain-rate stress-strain response of thin iridium specimens investigated in this study. We analyzed the difficulties encountered in high-temperature Kolsky compression bar testing of thin iridium alloy specimens. Appropriate modifications were made to the current high-temperature Kolsky compression bar technique to obtain reliable compressive stress-strain response of an iridium alloy at high strain rates (300 – 10000 s-1) and temperatures (750°C and 1030°C). Uncertainties in such high-temperature high-strain-rate experiments on thin iridium specimens were also analyzed. The compressive stress-strain response of the iridium alloy showed significant sensitivity to strain rate and temperature.

  14. 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)

  15. Temperature Distribution in a Displacement Ventilated Room

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The vertical temperature gradient is normally given as a linear temperature distribution between a minimum temperature close to the floor and a maximum temperature close to the ceiling. The minimum temperature can either be a constant fraction of a load dependent difference or it can be connected...

  16. Room temperature and productivity in office work

    Energy Technology Data Exchange (ETDEWEB)

    Seppanen, O.; Fisk, W.J.; Lei, Q.H.

    2006-07-01

    Indoor temperature is one of the fundamental characteristics of the indoor environment. It can be controlled with a degree of accuracy dependent on the building and its HVAC system. The indoor temperature affects several human responses, including thermal comfort, perceived air quality, sick building syndrome symptoms and performance at work. In this study, we focused on the effects of temperature on performance at office work. We included those studies that had used objective indicators of performance that are likely to be relevant in office type work, such as text processing, simple calculations (addition, multiplication), length of telephone customer service time, and total handling time per customer for call-center workers. We excluded data from studies of industrial work performance. We calculated from all studies the percentage of performance change per degree increase in temperature, and statistically analyzed measured work performance with temperature. The results show that performance increases with temperature up to 21-22 C, and decreases with temperature above 23-24 C. The highest productivity is at temperature of around 22 C. For example, at the temperature of 30 C, the performance is only 91.1% of the maximum i.e. the reduction in performance is 8.9%.

  17. 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.

  18. 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...

  19. 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

  20. Airflow and Temperature Distribution in Rooms with Displacement Ventilation

    DEFF Research Database (Denmark)

    Jacobsen, T. V.

    This thesis deals with air flow and temperature distribution in a room ventilated by the displacement principle. The characteristic features of the ventilation system are treated in the whole room but main emphasis is laid on the analysis of the stratified flow region in front of the inlet device....... After a prefatory description of the background and the fundamentals of displacement ventilation the objectives of the current study are specified. The subsequent sections describe the measurements of velocity and temperature profiles carried out in a full scale test room. Based on experimental data...... of measured data is of crucial importance. Qualitatively satisfactory results do not ensure quantitative agreement....

  1. 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.

  2. Mechanical Behavior of AZ31B Mg Alloy Sheets under Monotonic and Cyclic Loadings at Room and Moderately Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Ngoc-Trung Nguyen

    2014-02-01

    Full Text Available Large-strain monotonic and cyclic loading tests of AZ31B magnesium alloy sheets were performed with a newly developed testing system, at different temperatures, ranging from room temperature to 250 °C. Behaviors showing significant twinning during initial in-plane compression and untwinning in subsequent tension at and slightly above room temperature were recorded. Strong yielding asymmetry and nonlinear hardening behavior were also revealed. Considerable Bauschinger effects, transient behavior, and variable permanent softening responses were observed near room temperature, but these were reduced and almost disappeared as the temperature increased. Different stress–strain responses were inherent to the activation of twinning at lower temperatures and non-basal slip systems at elevated temperatures. A critical temperature was identified to account for the transition between the twinning-dominant and slip-dominant deformation mechanisms. Accordingly, below the transition point, stress–strain curves of cyclic loading tests exhibited concave-up shapes for compression or compression following tension, and an unusual S-shape for tension following compression. This unusual shape disappeared when the temperature was above the transition point. Shrinkage of the elastic range and variation in Young’s modulus due to plastic strain deformation during stress reversals were also observed. The texture-induced anisotropy of both the elastic and plastic behaviors was characterized experimentally.

  3. 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.

  4. Room temperature ferromagnetic gadolinium silicide nanoparticles

    Science.gov (United States)

    Hadimani, Magundappa Ravi L.; Gupta, Shalabh; Harstad, Shane; Pecharsky, Vitalij; Jiles, David C.

    2018-03-06

    A particle usable as T1 and T2 contrast agents is provided. The particle is a gadolinium silicide (Gd5Si4) particle that is ferromagnetic at temperatures up to 290 K and is less than 2 .mu.m in diameter. An MRI contrast agent that includes a plurality of gadolinium silicide (Gd.sub.5Si.sub.4) particles that are less than 1 .mu.m in diameter is also provided. A method for creating gadolinium silicide (Gd5Si4) particles is also provided. The method includes the steps of providing a Gd5Si4 bulk alloy; grinding the Gd5Si4 bulk alloy into a powder; and milling the Gd5Si4 bulk alloy powder for a time of approximately 20 minutes or less.

  5. Room temperature ferromagnetic gadolinium silicide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hadimani, Magundappa Ravi L.; Gupta, Shalabh; Harstad, Shane; Pecharsky, Vitalij; Jiles, David C.

    2018-03-06

    A particle usable as T1 and T2 contrast agents is provided. The particle is a gadolinium silicide (Gd5Si4) particle that is ferromagnetic at temperatures up to 290 K and is less than 2 .mu.m in diameter. An MRI contrast agent that includes a plurality of gadolinium silicide (Gd.sub.5Si.sub.4) particles that are less than 1 .mu.m in diameter is also provided. A method for creating gadolinium silicide (Gd5Si4) particles is also provided. The method includes the steps of providing a Gd5Si4 bulk alloy; grinding the Gd5Si4 bulk alloy into a powder; and milling the Gd5Si4 bulk alloy powder for a time of approximately 20 minutes or less.

  6. Effects of Elevated Temperature on Compressive Strength Of Concrete

    African Journals Online (AJOL)

    This study presents the results of investigation of the effects of elevated temperatures on the compressive strength of Grade 40 concrete. A total of thirty cube specimens were cast, cured in water at ambient temperature in the laboratory and subjected to various temperature regimes before testing. A concrete mix of 1:1:3 ...

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. Stainless steel component with compressed fiber Bragg grating for high temperature sensing applications

    Science.gov (United States)

    Jinesh, Mathew; MacPherson, William N.; Hand, Duncan P.; Maier, Robert R. J.

    2016-05-01

    A smart metal component having the potential for high temperature strain sensing capability is reported. The stainless steel (SS316) structure is made by selective laser melting (SLM). A fiber Bragg grating (FBG) is embedded in to a 3D printed U-groove by high temperature brazing using a silver based alloy, achieving an axial FBG compression of 13 millistrain at room temperature. Initial results shows that the test component can be used for up to 700°C for sensing applications.

  13. 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.

  14. 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.

  15. 0-D study of the compression of low temperature spheromaks

    International Nuclear Information System (INIS)

    Meyerhofer, D.D.; Hulse, R.A.; Zweibel, E.G.

    1985-09-01

    Compression of low temperature spheromak plasmas has been studied with the aid of a O-D two-fluid computer code. It is found that in a plasma which is radiation dominated, the electron temperature can be increased by up to a factor of seven for a compression of a factor of two, provided the temperature is above some critical value (approx.25eV) and the electron density particle confinement time product n/sub e/tau/sub p/ greater than or equal to 1 x 10 9 s/cm 3 . If the energy balance is dominated by particle confinement losses rather than radiation losses, the effect of compression is to raise the temperature as T/sub e/ approx.C/sup 6/5/, for constant tau/sub p/

  16. 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)

  17. 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.

  18. 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...

  19. Effect of elevated temperature on the compressive strength of ...

    African Journals Online (AJOL)

    Based on results of tests, partial replacement of cement with 10 % PSMS is recommended for use in concrete production and resistance to elevated temperature. The studies show that at this replacement, the concrete compressive strength is not adversely affected when the elevated temperature reaches 500°C. Keywords: ...

  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. Temperature measurements of shock-compressed deuterium

    International Nuclear Information System (INIS)

    Holmes, N.C.; Ross, M.; Nellis, W.J.

    1994-11-01

    The authors measured the temperatures of single and double-shocked D 2 and H 2 up to 85 GPa (0.85 Mbar) and 5,200 K. While single shock temperatures, at pressures to 23 GPa, agree well with previous models, the double shock temperatures are as much as 40% lower than predicted. This is believed to be caused by molecular dissociation, and a new model of the hydrogen EOS at extreme conditions has been developed which correctly predicts their observations. These data and model have important implications for programs which use condensed-phase hydrogen in implosion systems

  2. Temperature and moisture content effects on compressive strength parallel to the grain of paricá

    Directory of Open Access Journals (Sweden)

    Manuel Jesús Manríquez Figueroa

    Full Text Available The aim of this study is to evaluate the effect of the temperature and moisture content on the compressive strength parallel to the grain of paricá (Schizolobium amazonicum Huber ex. Ducke from cultivated forests. The experiments were carried out on 3 timber samples under different conditions: heated (HT, thermal treatment (TT and water saturated (WS. The HT sample consisted of 105 clear specimens assembled in 15 groups, the TT consisted of 90 clear specimens assembled in 15 groups and the WS consisted of 90 clear specimens assembled in 9 groups. The specimens from HT and WS samples were tested at a temperature range from 20 to 230 ºC and 20 to 100 ºC, respectively. The HT specimens were tested at ambient temperature, but after being submitted to thermal treatment. The HT, TT and WS samples present a decrease in the compressive strength, reaching 65%, 76% and 59% of the compressive strength at room temperature, respectively. The decrease in the compressive strength of the HT and WS samples can be associated to the thermal degradation of wood polymers and the moisture content. For the TT sample, the strength increased for a pre-heating temperature of up to 170 °C due to the reduction in the moisture content of the specimens.

  3. Evolution of interphase and intergranular stresses in Zr-2.5Nb during room temperature deformation

    International Nuclear Information System (INIS)

    Cai, S.; Daymond, M.R.; Holt, R.A.; Gharghouri, M.A.; Oliver, E.C.

    2009-01-01

    Both in situ tension and compression tests have been carried out on textured Zr-2.5Nb plate material at room temperature. Deformation along all the three principle plate directions has been studied and the evolution of interphase and intergranular strains along the loading and the principle Poisson's directions has been investigated by neutron diffraction. The evolution of interphase and intergranular strain was determined by the relative phase properties, crystal properties and texture distribution. The average phase behaviors are similar during tension and compression, where the β-phase in this material is stronger than the α-phase. The asymmetric yielding of the α-{0 0 0 2} grain family results in a relatively large intergranular strain in the loading direction during compression and different dependence of strength during tension and compression on texture. The combination of the thermal residual stress and the asymmetric CRSS in the axis gives the {0 0 0 2} grain family a higher strength in compression than in tension

  4. Compressive fatigue tests on a unidirectional glass/polyester composite at cryogenic temperatures

    International Nuclear Information System (INIS)

    Stone, E.L.; El-Marazki, L.O.; Young, W.C.

    1979-01-01

    The fatigue testing of a unidirectional glass-reinforced polyester composite at cryogenic temperatures to simulate the cyclic compressive loads of the magnet support struts in a superconductive magnetic energy storage unit is reported. Right circular cylindrical specimens were tested at 77, 4.2 K and room temperature at different stress levels using a 1-Hz haversine waveform imposed upon a constant baseload in a load-controlled closed-loop electrohydraulic test machine. Two failure modes, uniform mushrooming near one end and a 45 deg fracture line through the middle of the specimen, are observed, with no systematic difference in fatigue life between the modes. Fatigue lives obtained at 77 and 4.2 K are found to be similar, with fatigue failure at 100,000 cycles occurring at stress levels of 70 and 75% of the ultimate compressive strengths of specimens at room temperature and 77 K, respectively. The room temperature fatigue lives of the glass/polyester specimens are found to be intermediate between those reported for glass/epoxy composites with different glass contents costing over twice as much

  5. Temperature measurement of tin under shock compression

    International Nuclear Information System (INIS)

    Hereil, Pierre-Louis; Mabire, Catherine

    2002-01-01

    The results of pyrometric measurements performed at the interface of a tin target with a LiF window material are presented for stresses ranging from 38 to 55 GPa. The purpose of the study is to analyze the part of the interface in the temperature measurement by a multi-channel pyrometric device. The results show that the glue used at target/window interface remains transparent under shock. The values of temperature measured at the tin/LiF interface are consistent with the behavior of tin under shock

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Temperature dependence of dynamic behavior of commercially pure titanium by the compression test

    International Nuclear Information System (INIS)

    Lee, Su Min; Seo, Song Won; Park, Kyoung Joon; Min, Oak Key

    2003-01-01

    The mechanical behavior of a Commercially Pure Titanium (CP-Ti) is investigated at high temperature Split Hopkinson Pressure Bar (SHPB) compression test with high strain-rate. Tests are performed over a temperature range from room temperature to 1000 .deg. C with interval of 200 deg. C and a strain-rate range of 1900∼2000/sec. The true flow stress-true strain relations depending on temperature are achieved in these tests. For construction of constitutive equation from the true flow stress-true strain relation, parameters for the Johnson-Cook constitutive equation is determined. And the modified Johnson-Cook equation is used for investigation of behavior of flow stress in vicinity of recrystallization temperature. The modified Johnson-Cook constitutive equation is more suitable in expressing the dynamic behavior of a CP-Ti at high temperature, i.e. about recrystallization temperature

  11. 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.)

  12. 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.

  13. 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.

  14. Al based ultra-fine eutectic with high room temperature plasticity and elevated temperature strength

    Energy Technology Data Exchange (ETDEWEB)

    Tiwary, C.S., E-mail: cst311@gmail.com [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kashyap, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kim, D.H. [Center for Non-Crystalline Materials, Department of Metallurgical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India)

    2015-07-15

    Developments of aluminum alloys that can retain strength at and above 250 °C present a significant challenge. In this paper we report an ultrafine scale Al–Fe–Ni eutectic alloy with less than 3.5 at% transition metals that exhibits room temperature ultimate tensile strength of ~400 MPa with a tensile ductility of 6–8%. The yield stress under compression at 300 °C was found to be 150 MPa. We attribute it to the refinement of the microstructure that is achieved by suction casting in copper mold. The characterization using scanning and transmission electron microscopy (SEM and TEM) reveals an unique composite structure that contains the Al–Al{sub 3}Ni rod eutectic with spacing of ~90 nm enveloped by a lamellar eutectic of Al–Al{sub 9}FeNi (~140 nm). Observation of subsurface deformation under Vickers indentation using bonded interface technique reveals the presence of extensive shear banding during deformation that is responsible for the origin of ductility. The dislocation configuration in Al–Al{sub 3}Ni eutectic colony indicates accommodation of plasticity in α-Al with dislocation accumulation at the α-Al/Al{sub 3}Ni interface boundaries. In contrast the dislocation activities in the intermetallic lamellae are limited and contain set of planner dislocations across the plates. We present a detailed analysis of the fracture surface to rationalize the origin of the high strength and ductility in this class of potentially promising cast alloy.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Estimation of exit temperatures in the isentropic compression of real ...

    African Journals Online (AJOL)

    This paper presents the estimation of exit temperatures in the isentropic compression of real gases based on the Peng-Robinson equation of state and entropy balance method. The methods were applied to Ar, N2, CH4, CO2, C2H4 and C2H6. Data obtained revealed that isentropic exponent method provides useful results ...

  12. A materials test system for static compression at elevated temperatures

    Science.gov (United States)

    Korellis, J. S.; Steinhaus, C. A.; Totten, J. J.

    1992-06-01

    This report documents modifications to our existing computer-controlled compression testing system to allow elevated temperature testing in an evacuated environment. We have adopted an 'inverse' design configuration where the evacuated test volume is located within the induction heating coil, eliminating the expense and minimizing the evacuation time of a much larger traditional vacuum chamber.

  13. 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.

  14. 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

  15. 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.

  16. Evolution of interphase and intergranular strain in zirconium-niobium alloys during deformation at room temperature

    Science.gov (United States)

    Cai, Song

    Zr-2.5Nb is currently used for pressure tubes in the CANDU (CANada Deuterium Uranium) reactor. A complete understanding of the deformation mechanism of Zr-2.5Nb is important if we are to accurately predict the in-reactor performance of pressure tubes and guarantee normal operation of the reactors. This thesis is a first step in gaining such an understanding; the deformation mechanism of ZrNb alloys at room temperature has been evaluated through studying the effect of texture and microstructure on deformation. In-situ neutron diffraction was used to monitor the evolution of the lattice strain of individual grain families along both the loading and Poisson's directions and to track the development of interphase and intergranular strains during deformation. The following experiments were carried out with data interpreted using elasto-plastic modeling techniques: (1) Compression tests of a 100%betaZr material at room temperature. (2) Tension and compression tests of hot rolled Zr-2.5Nb plate material. (3) Compression of annealed Zr-2.5Nb. (4) Cyclic loading of the hot rolled Zr-2.5Nb. (5) Compression tests of ZrNb alloys with different Nb and oxygen contents. The experimental results were interpreted using a combination of finite element (FE) and elasto-plastic self-consistent (EPSC) models. The phase properties and phase interactions well represented by the FE model, the EPSC model successfully captured the evolution of intergranular constraint during deformation and provided reasonable estimates of the critical resolved shear stress and hardening parameters of different slip systems under different conditions. The consistency of the material parameters obtained by the EPSC model allows the deformation mechanism at room temperature and the effect of textures and microstructures of ZrNb alloys to be understood. This work provides useful information towards manufacturing of Zr-2.5Nb components and helps in producing ideal microstructures and material properties for

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  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. Elastic Modulus of Foamcrete in Compression and Bending at Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Md Azree Othuman Mydin

    2012-09-01

    Full Text Available This paper will presents the experimental results that have been performed to examine and characterize the mechanical properties of foamcrete at elevated temperatures. Foamcrete of 650 and 1000 kg/m 3 density were cast and tested under compression and bending. The tests were done at room temperature, 100, 200, 300, 400, 500, and 600°C. The results of this study consistently demonstrated that the loss in stiffness for cement based material like foamcrete at elevated temperatures occurs predominantly after about 95°C, regardless of density. This indicates that the primary mechanism causing stiffness degradation is microcracking, which occurs as water expands and evaporates from the porous body. As expected, reducing the density of LFC reduces its strength and stiffness. However, for LFC of different densities, the normalised strength-temperature and stiffnesstemperature relationships are very similar.

  3. Optimal Chest Compression Rate and Compression to Ventilation Ratio in Delivery Room Resuscitation: Evidence from Newborn Piglets and Neonatal Manikins

    Science.gov (United States)

    Solevåg, Anne Lee; Schmölzer, Georg M.

    2017-01-01

    Cardiopulmonary resuscitation (CPR) duration until return of spontaneous circulation (ROSC) influences survival and neurologic outcomes after delivery room (DR) CPR. High quality chest compressions (CC) improve cerebral and myocardial perfusion. Improved myocardial perfusion increases the likelihood of a faster ROSC. Thus, optimizing CC quality may improve outcomes both by preserving cerebral blood flow during CPR and by reducing the recovery time. CC quality is determined by rate, CC to ventilation (C:V) ratio, and applied force, which are influenced by the CC provider. Thus, provider performance should be taken into account. Neonatal resuscitation guidelines recommend a 3:1 C:V ratio. CCs should be delivered at a rate of 90/min synchronized with ventilations at a rate of 30/min to achieve a total of 120 events/min. Despite a lack of scientific evidence supporting this, the investigation of alternative CC interventions in human neonates is ethically challenging. Also, the infrequent occurrence of extensive CPR measures in the DR make randomized controlled trials difficult to perform. Thus, many biomechanical aspects of CC have been investigated in animal and manikin models. Despite mathematical and physiological rationales that higher rates and uninterrupted CC improve CPR hemodynamics, studies indicate that provider fatigue is more pronounced when CC are performed continuously compared to when a pause is inserted after every third CC as currently recommended. A higher rate (e.g., 120/min) is also more fatiguing, which affects CC quality. In post-transitional piglets with asphyxia-induced cardiac arrest, there was no benefit of performing continuous CC at a rate of 90/min. Not only rate but duty cycle, i.e., the duration of CC/total cycle time, is a known determinant of CC effectiveness. However, duty cycle cannot be controlled with manual CC. Mechanical/automated CC in neonatal CPR has not been explored, and feedback systems are under-investigated in this

  4. 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

  5. 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.

  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. 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.

  9. 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.

  10. 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".

  11. 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.

  12. 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.

  13. 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.

  14. Room and low temperature synthesis of carbon nanofibres

    International Nuclear Information System (INIS)

    Boskovic, Bojan O.

    2002-01-01

    Carbon nanotubes and nanofibres have attracted attention in recent years as new materials with a number of very promising potential applications. Carbon nanotubes are potential candidates for field emitters in flat panel displays. Carbon nanofibres could also be used as a hydrogen storage material and as a filling material in polymer composites. Carbon nanotubes are already used as tips in scanning probe microscopy due to their remarkable mechanical and electrical properties, and could be soon used as nanotweezers. Use of carbon nanotubes in nanoelectronics will open further miniaturisation prospects. Temperatures ranging from 450 to 1000 deg C have been a required for catalytic growth of carbon nanotubes and nanofibres. Researchers have been trying to reduce the growth temperatures for decades. Low temperature growth conditions will allow the growth of carbon nanotubes on different substrates, such glass (below 650 deg C) and as plastics (below 150 deg C) over relatively large areas, which is especially suitable for fiat panel display applications. Room temperature growth conditions could open up the possibility of using different organic substrates and bio-substrates for carbon nanotubes synthesis. Carbon nanofibres have been synthesised at room temperature and low temperatures below 250 deg C using radio frequency plasma enhanced chemical vapour deposition (r.f. PECVD). Previously, the growth of carbon nanofibres has been via catalytic decomposition of hydrocarbons or carbon monoxide at temperatures above 300 deg C. To the best of our knowledge, this is the first evidence of the growth of carbon nanofibres at temperatures lower than 300 deg C by any method. The use of a transition metal catalyst and r.f.-PECVD system is required for the growth of the carbon nanofibre when a hydrocarbon flows above the catalyst. Within the semiconductor industry r.f.-PECVD is a well established technique which lends itself for the growth of carbon nanofibres for various

  15. 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.

  16. 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.

  17. Pt/ZnO nanoarray nanogenerator as self-powered active gas sensor with linear ethanol sensing at room temperature.

    Science.gov (United States)

    Zhao, Yayu; Lai, Xuan; Deng, Ping; Nie, Yuxin; Zhang, Yan; Xing, Lili; Xue, Xinyu

    2014-03-21

    A self-powered gas sensor that can actively detect ethanol at room temperature has been realized from a Pt/ZnO nanoarray nanogenerator. Pt nanoparticles are uniformly distributed on the whole surface of ZnO nanowires. The piezoelectric output of Pt/ZnO nanoarrays can act not only as a power source, but also as a response signal to ethanol at room temperature. Upon exposure to dry air and 1500 ppm ethanol at room temperature, the piezoelectric output of the device under the same compressive strain is 0.672 and 0.419 V, respectively. Moreover, a linear dependence of the sensitivity on the ethanol concentration is observed. Such a linear ethanol sensing at room temperature can be attributed to the atmosphere-dependent variety of the screen effect on the piezoelectric output of ZnO nanowires, the catalytic properties of Pt nanoparticles, and the Schottky barriers at Pt/ZnO interfaces. The present results can stimulate research in the direction of designing new material systems for self-powered room-temperature gas sensing.

  18. 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

  19. High temperature absorption compression heat pump for industrial waste heat

    DEFF Research Database (Denmark)

    Reinholdt, Lars; Horntvedt, B.; Nordtvedt, S. R.

    2016-01-01

    Heat pumps are currently receiving extensive interest because they may be able to support the integration of large shares of fluctuating electricity production based on renewable sources, and they have the potential for the utilization of low temperature waste heat from industry. In most industries......, the needed temperature levels often range from 100°C and up, but until now, it has been quite difficult to find heat pump technologies that reach this level, and thereby opening up the large-scale heat recovery in the industry. Absorption compression heat pumps can reach temperatures above 100°C......, and they have proved themselves a very efficient and reliable technology for applications that have large temperature changes on the heat sink and/or heat source. The concept of Carnot and Lorenz efficiency and its use in the analysis of system integration is shown. A 1.25 MW system having a Carnot efficiency...

  20. Low temperature and high pressure crystals of room temperature ionic liquid: N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate

    International Nuclear Information System (INIS)

    Abe, Hiroshi; Imai, Yusuke; Takekiyo, Takahiro; Yoshimura, Yukihiro; Hamaya, Nozomu

    2014-01-01

    Crystals of room temperature ionic liquid (RTIL) are obtained separately at low temperature or under high pressure. The RTIL is N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate, [DEME][BF 4 ]. At ambient pressure, low-temperature (LT) crystals appeared on slow cooling. By simultaneous X-ray diffraction and differential scanning calorimetry (DSC) measurements, metastable monoclinic and stable orthorhombic phases coexist in pure [DEME][BF 4 ]. Furthermore, the DSC thermal trace indicates that the metastable monoclinic phase was stabilized by adding water. In contrast, on compression process up to 7.6 GPa, crystallization is completely suppressed even upon slow compression. Direct observations using optical microscopy also support no crystal domain growth on compression process. High-pressure (HP) crystals at room temperature were seen only on decompression process, where two different kinds of crystals appeared subsequently. By crystal structure analysis, the LT crystal structures have no relation with the HP ones. Moreover, both metastable monoclinic phase at low temperature and higher pressure crystal has a folding molecular conformation and anti-parallel pairing of the [DEME] cation as the instability factors

  1. 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.

  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. 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

  10. 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.

  11. 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.

  12. “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...

  13. 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.

  14. 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.

  15. 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.

  16. Room temperature deformation mechanisms in ultrafine-grained materials processed by hot isostatic pressing

    International Nuclear Information System (INIS)

    Cao, W.Q.; Dirras, G.F.; Benyoucef, M.; Bacroix, B.

    2007-01-01

    Ultrafine-grained (uf-g) and microcrystalline-grained (mc-g) irons have been fabricated by hot isostatic pressing of nanopowders. The mechanical properties have been characterized by compressive tests at room temperature and the resulting microstructures and textures have been determined by combining electron back scatter diffraction and transmission electron microscopy. A transition of the deformation mode, from work hardening to work softening occurs for grain sizes below ∼1 μm, reflecting a transition of the deformation mode from homogeneous to localized deformation into shear bands (SBs). The homogeneous deformation is found to be lattice dislocation-based while the deformation within SBs involves lattice dislocations as well as boundary-related mechanisms, possibly grain boundary sliding accommodated by boundary opening

  17. 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

  18. 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.

  19. High temperature compression tests performed on doped fuels

    Energy Technology Data Exchange (ETDEWEB)

    Duguay, C.; Mocellin, A.; Dehaudt, P. [Commissariat a l`Energie Atomique, CEA Grenoble (France); Fantozzi, G. [INSA Lyon - GEMPPM, Villeurbanne (France)

    1997-12-31

    The use of additives of corundum structure M{sub 2}O{sub 3} (M=Cr, Al) is an effective way of promoting grain growth of uranium dioxide. The high-temperature compressive deformation of large-grained UO{sub 2} doped with these oxides has been investigated and compared with that of pure UO{sub 2} with a standard microstructure. Such doped fuels are expected to exhibit enhanced plasticity. Their use would therefore reduce the pellet-cladding mechanical interaction and thus improve the performances of the nuclear fuel. (orig.) 5 refs.

  20. High temperature compression tests performed on doped fuels

    International Nuclear Information System (INIS)

    Duguay, C.; Mocellin, A.; Dehaudt, P.; Fantozzi, G.

    1997-01-01

    The use of additives of corundum structure M 2 O 3 (M=Cr, Al) is an effective way of promoting grain growth of uranium dioxide. The high-temperature compressive deformation of large-grained UO 2 doped with these oxides has been investigated and compared with that of pure UO 2 with a standard microstructure. Such doped fuels are expected to exhibit enhanced plasticity. Their use would therefore reduce the pellet-cladding mechanical interaction and thus improve the performances of the nuclear fuel. (orig.)

  1. 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.

  2. Electrodeless, multi-megawatt reactor for room-temperature, lithium-6/deuterium nuclear reactions

    International Nuclear Information System (INIS)

    Drexler, J.

    1993-01-01

    This paper describes a reactor design to facilitate a room-temperature nuclear fusion/fission reaction to generate heat without generating unwanted neutrons, gamma rays, tritium, or other radioactive products. The room-temperature fusion/fission reaction involves the sequential triggering of billions of single-molecule, 6 LiD 'fusion energy pellets' distributed in lattices of a palladium ion accumulator that also acts as a catalyst to produce the molecules of 6 LiD from a solution comprising D 2 O, 6 LiOD with D 2 gas bubbling through it. The D 2 gas is the source of the negative deuterium ions in the 6 LiD molecules. The next step is to trigger a first nuclear fusion/fission reaction of some of the 6 LiD molecules, according to the well-known nuclear reaction: 6 Li + D → 2 4 He + 22.4 MeV. The highly energetic alpha particles ( 4 He nuclei) generated by this nuclear reaction within the palladium will cause shock and vibrations in the palladium lattices, leading to compression of other 6 LiD molecules and thereby triggering a second series of similar fusion/fission reactions, leading to a third series, and so on. The absorption of the kinetic energy in the palladium will, in turn, generate a continuous flow of heat into the heavy water carrier, which would be removed with a heat exchanger. (author)

  3. Annual report on the high temperature triaxial compression device

    International Nuclear Information System (INIS)

    Williams, N.D.; Menk, P.; Tully, R.; Houston, W.N.

    1981-01-01

    The investigation of the environmental effects on the mechanical and engineering properties of deep-sea sediments was initiated on June 15, 1980. The task is divided into three categories. First, the design and fabrication of a High Temperature Triaxial Compression Device (HITT). Second, an investigation of the mechanical and engineering properties of the deep-sea sediments at temperatures ranging from 277 to 473 degrees kelvin. Third, assist in the development of constitutive relationships and an analytical model which describe the temperature dependent creep deformations of the deep-sea sediments. The environmental conditions under which the soil specimens are to be tested are variations in temperature from 277 to 473 degrees kelvin. The corresponding water pressure will vary up to about 2.75 MPa as required to prevent boiling of the water and assure saturation of the test specimens. Two groups of tests are to be performed. First, triaxial compression tests during which strength measurements and constant head permeability determinations shall be made. Second, constant stress creep tests, during which axial and lateral strains shall be measured. In addition to the aforementioned variables, data shall also be acquired to incorporate the effects of consolidation history, strain rate, and heating rate. The bulk of the triaxial tests are to be performed undrained. The strength measurement tests are to be constant-rate-of-strain and the creep tests are to be constant-stress tests. The study of the mechanical properties of the deep-sea sediments as a function of temperature is an integrated program

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Effect of intergranular stress on yielding of 316H during room temperature cyclic loading

    International Nuclear Information System (INIS)

    Al Mamun, Abdullah; Moat, Richard; Bouchard, John; Kelleher, Joe

    2016-01-01

    Assessment of cyclic deformation is an integral part of nuclear power plant life assessment code, as many of the components in plant go through scheduled and unscheduled cyclic deformation owing to varying thermal and mechanical stresses. In polycrystalline material like 316H, a type of micro stress known as intergranular stress is generated due to elastic and plastic anisotropies during such cyclic loading. In tension-compression loading cycles, these stresses remain in the material as a residual stress upon unloading to zero stress from the tensile/compressive peak or intermediates stresses. The magnitude of these stresses vary depending on the point in the cycle from which it was unloaded from. When the material is re-loaded either in the same or reverse loading direction these residual stresses increase or decrease the effective stress acting in the material and as such the macroscopic yield stress of the material in subsequent cycle is changed significantly. The magnitude of intergranular stresses in many differently oriented grain families can be measured simultaneously using time of flight (ToF) neutron diffraction technique. In this paper, we have used this technique to experimentally study, how these intergranular stresses affect the yield (proof) stress of 316H at room temperature. (author)

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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...

  20. 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.

  1. 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

  2. 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.)

  3. 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.

  4. 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

  5. Objective and subjective quality assessment of geometry compression of reconstructed 3D humans in a 3D virtual room

    Science.gov (United States)

    Mekuria, Rufael; Cesar, Pablo; Doumanis, Ioannis; Frisiello, Antonella

    2015-09-01

    Compression of 3D object based video is relevant for 3D Immersive applications. Nevertheless, the perceptual aspects of the degradation introduced by codecs for meshes and point clouds are not well understood. In this paper we evaluate the subjective and objective degradations introduced by such codecs in a state of art 3D immersive virtual room. In the 3D immersive virtual room, users are captured with multiple cameras, and their surfaces are reconstructed as photorealistic colored/textured 3D meshes or point clouds. To test the perceptual effect of compression and transmission, we render degraded versions with different frame rates in different contexts (near/far) in the scene. A quantitative subjective study with 16 users shows that negligible distortion of decoded surfaces compared to the original reconstructions can be achieved in the 3D virtual room. In addition, a qualitative task based analysis in a full prototype field trial shows increased presence, emotion, user and state recognition of the reconstructed 3D Human representation compared to animated computer avatars.

  6. 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.

  7. 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

  8. 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.

  9. CFD analysis of the temperature field in emergency pump room in Loviisa NPP

    Energy Technology Data Exchange (ETDEWEB)

    Rämä, Tommi, E-mail: tommi.rama@fortum.com [Fortum Power and Heat, P.O.B. 100, FI-00048 Fortum (Finland); Toppila, Timo, E-mail: timo.toppila@fortum.com [Fortum Power and Heat, P.O.B. 100, FI-00048 Fortum (Finland); Kelavirta, Teemu, E-mail: teemu.kelavirta@fortum.com [Fortum Power and Heat, Loviisa Power Plant, P.O.B. 23, FI-07901 Loviisa (Finland); Martin, Pasi, E-mail: pasi.martin@fortum.com [Fortum Power and Heat, Loviisa Power Plant, P.O.B. 23, FI-07901 Loviisa (Finland)

    2014-11-15

    Highlights: • Laser scanned room geometry from Loviisa NPP was utilized for CFD simulation. • Uncertainty of CFD simulation was estimated using the Grid Convergence Index. • Measured temperature field of pump room was reproduced with CFD simulation. - Abstract: In the Loviisa Nuclear Power Plant (NPP) six emergency pumps belonging to the same redundancy are located in the same room. During a postulated accident the cooling of the room is needed as the engines of the emergency pumps generate heat. Cooling is performed with fans blowing air to the upper part of the room. Temperature limits have been given to the operating conditions of the main components in order to ensure their reliable operation. Therefore the temperature field of the room is important to know. Temperature measurements were made close to the most important components of the pump room to get a better understanding of the temperature field. For these measurements emergency pumps and cooling fan units were activated. To simulate conditions during a postulated accident additional warm-air heaters were used. Computational fluid dynamic (CFD) simulations were made to support plant measurements. For the CFD study one of the pump rooms of Loviisa NPP was scanned with a laser and this data converted to detailed 3-D geometry. Tetrahedral computation grid was created inside the geometry. Grid sensitivity studies were made, and the model was then validated against the power plant tests. With CFD the detailed temperature and flow fields of the whole room were produced. The used CFD model was able to reproduce the temperature field of the measurements. Two postulated accident cases were simulated. In the cases the operating cooling units were varied. The temperature profile of the room changes significantly depending on which units are cooling and which only circulating the air. The room average temperature stays approximately the same. The simulation results were used to ensure the acceptable operating

  10. 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.

  11. Effect of evaporator temperature on vapor compression refrigeration system

    Directory of Open Access Journals (Sweden)

    Abdullah A.A.A. Al-Rashed

    2011-12-01

    Full Text Available This paper presents a comparable evaluation of R600a (isobutane, R290 (propane, R134a, R22, for R410A, and R32 an optimized finned-tube evaporator, and analyzes the evaporator effect on the system coefficient of performance (COP. Results concerning the response of a refrigeration system simulation software to an increase in the amount of oil flowing with the refrigerant are presented. It is shown that there is optima of the apparent overheat value, for which either the exchanged heat or the refrigeration coefficient of performance (COP is maximized: consequently, it is not possible to optimize both the refrigeration COP and the evaporator effect. The obtained evaporator optimization results were incorporated in a conventional analysis of the vapor compression system. For a theoretical cycle analysis without accounting for evaporator effects, the COP spread for the studied refrigerants was as high as 11.7%. For cycle simulations including evaporator effects, the COP of R290 was better than that of R22 by up to 3.5%, while the remaining refrigerants performed approximately within a 2% COP band of the R22 baseline for the two condensing temperatures considered.

  12. Direct measurement of osmotic pressure of glycosaminoglycan solutions by membrane osmometry at room temperature.

    Science.gov (United States)

    Chahine, Nadeen O; Chen, Faye H; Hung, Clark T; Ateshian, Gerard A

    2005-09-01

    Articular cartilage is a hydrated soft tissue composed of negatively charged proteoglycans fixed within a collagen matrix. This charge gradient causes the tissue to imbibe water and swell, creating a net osmotic pressure that enhances the tissue's ability to bear load. In this study we designed and utilized an apparatus for directly measuring the osmotic pressure of chondroitin sulfate, the primary glycosaminoglycan found in articular cartilage, in solution with varying bathing ionic strength (0.015 M, 0.15 M, 0.5 M, 1 M, and 2 M NaCl) at room temperature. The osmotic pressure (pi) was found to increase nonlinearly with increasing chondroitin sulfate concentration and decreasing NaCl ionic bath environment. Above 1 M NaCl, pi changes negligibly with further increases in salt concentration, suggesting that Donnan osmotic pressure is negligible above this threshold, and the resulting pressure is attributed to configurational entropy. Results of the current study were also used to estimate the contribution of osmotic pressure to the stiffness of cartilage based on theoretical and experimental considerations. Our findings indicate that the osmotic pressure resulting from configurational entropy is much smaller in cartilage (based on an earlier study on bovine articular cartilage) than in free solution. The rate of change of osmotic pressure with compressive strain is found to contribute approximately one-third of the compressive modulus (H(A)(eff)) of cartilage (Pi approximately H(A)(eff)/3), with the balance contributed by the intrinsic structural modulus of the solid matrix (i.e., H(A) approximately 2H(A)(eff)/3). A strong dependence of this intrinsic modulus on salt concentration was found; therefore, it appears that proteoglycans contribute structurally to the magnitude of H(A), in a manner independent of osmotic pressure.

  13. Pentacene on Ni(111): room-temperature molecular packing and temperature-activated conversion to graphene.

    Science.gov (United States)

    Dinca, L E; De Marchi, F; MacLeod, J M; Lipton-Duffin, J; Gatti, R; Ma, D; Perepichka, D F; Rosei, F

    2015-02-21

    We investigate, using scanning tunnelling microscopy, the adsorption of pentacene on Ni(111) at room temperature and the behaviour of these monolayer films with annealing up to 700 °C. We observe the conversion of pentacene into graphene, which begins from as low as 220 °C with the coalescence of pentacene molecules into large planar aggregates. Then, by annealing at 350 °C for 20 minutes, these aggregates expand into irregular domains of graphene tens of nanometers in size. On surfaces where graphene and nickel carbide coexist, pentacene shows preferential adsorption on the nickel carbide phase. The same pentacene to graphene transformation was also achieved on Cu(111), but at a higher activation temperature, producing large graphene domains that exhibit a range of moiré superlattice periodicities.

  14. Semiconductor terahertz technology devices and systems at room temperature operation

    CERN Document Server

    Carpintero, G; Hartnagel, H; Preu, S; Raisanen, A

    2015-01-01

    Key advances in Semiconductor Terahertz (THz) Technology now promises important new applications enabling scientists and engineers to overcome the challenges of accessing the so-called "terahertz gap".  This pioneering reference explains the fundamental methods and surveys innovative techniques in the generation, detection and processing of THz waves with solid-state devices, as well as illustrating their potential applications in security and telecommunications, among other fields. With contributions from leading experts, Semiconductor Terahertz Technology: Devices and Systems at Room Tempe

  15. 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.

  16. Mechanism of crack healing at room temperature revealed by atomistic simulations

    International Nuclear Information System (INIS)

    Li, J.; Fang, Q.H.; Liu, B.; Liu, Y.; Liu, Y.W.; Wen, P.H.

    2015-01-01

    Three dimensional molecular dynamics (MD) simulations are systematically carried out to reveal the mechanism of the crack healing at room temperature, in terms of the dislocation shielding and the atomic diffusion to control the crack closure, in a copper (Cu) plate suffering from a shear loading. The results show that the process of the crack healing is actualized through the dislocation emission at a crack tip accompanied with intrinsic stacking faults ribbon forming in the crack tip wake, the dislocation slipping in the matrix and the dislocation annihilation in the free surface. Dislocation included stress compressing the crack tip is examined from the MD simulations and the analytical models, and then the crack closes rapidly due to the assistance of the atomic diffusion induced by the thermal activation when the crack opening displacement is less than a threshold value. This phenomenon is very different from the previous results for the crack propagation under the external load applied because of the crack healing (advancing) largely dependent on the crystallographic orientations of crack and the directions of external loading. Furthermore, based on the energy characteristic and considering the crack size effect, a theoretical model is established to predict the relationships between the crack size and the shear stress which qualitatively agree well with that obtained in the MD simulations

  17. 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

  18. Compressive behaviour of hybrid fiber-reinforced reactive powder concrete after high temperature

    International Nuclear Information System (INIS)

    Zheng, Wenzhong; Li, Haiyan; Wang, Ying

    2012-01-01

    Highlights: ► We complete the high temperature test and compression test of RPC after 20–900 °C. ► The presence of steel fiber and polypropylene fiber can prevent RPC from spalling. ► Compressive strength increases first and then decreases with elevated temperatures. ► Microstructure deterioration is the root cause of macro-properties recession. ► Equations to express the compressive strength change with temperature are proposed. -- Abstract: This study focuses on the compressive properties and microstructures of reactive powder concrete (RPC) mixed with steel fiber and polypropylene fiber after exposure to 20–900 °C. The volume dosage of steel fiber and polypropylene fiber is (2%, 0.1%), (2%, 0.2%) and (1%, 0.2%). The effects of heating temperature, fiber content and specimen size on the compressive properties are analyzed. The microstructures of RPC exposed to different high temperatures are studied by scanning electron microscope (SEM). The results indicate that the compressive strength of hybrid fiber-reinforced RPC increases at first, then decreases with the increasing temperature, and the basic reason for the degradation of macro-mechanical properties is the deterioration of RPC microstructure. Based on the experimental results, equations to express the relationships of the compressive strength with the heating temperatures are established. Compared with normal-strength and high-strength concrete, the hybrid fiber-reinforced RPC has excellent capacity in resistance to high temperature.

  19. Low cycle fatigue behavior of Sanicro25 steel at room and at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Polák, Jaroslav, E-mail: polak@ipm.cz [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); CEITEC, Institute of Physics of Materials Academy of Sciences of the Czech Republic, Žižkova 22, Brno (Czech Republic); Petráš, Roman; Heczko, Milan; Kuběna, Ivo [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); Kruml, Tomáš [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); CEITEC, Institute of Physics of Materials Academy of Sciences of the Czech Republic, Žižkova 22, Brno (Czech Republic); Chai, Guocai [Sandvik Materials Technology, SE-811 81 Sandviken (Sweden); Linköping University, Engineering Materials, SE-581 83 Linköping (Sweden)

    2014-10-06

    Austenitic heat resistant Sanicro 25 steel developed for high temperature applications in power generation industry has been subjected to strain controlled low cycle fatigue tests at ambient and at elevated temperature in a wide interval of strain amplitudes. Fatigue hardening/softening curves, cyclic stress–strain curves and fatigue life curves were evaluated at room temperature and at 700 °C. The internal dislocation structures of the material at room and at elevated temperature were studied using transmission electron microscopy. High resolution surface observations and FIB cuts revealed early damage at room temperature in the form of persistent slip bands and at elevated temperature as oxidized grain boundary cracks. Dislocation arrangement study and surface observations were used to identify the cyclic slip localization and to discuss the fatigue softening/hardening behavior and the temperature dependence of the fatigue life.

  20. Loss of shear strength in polycrystalline tungsten under shock compression

    International Nuclear Information System (INIS)

    Dandekar, D.P.

    1976-01-01

    A reexamination of existing data on shock compression of polycrystalline tungsten at room temperature indicates that tungsten may be an exception to the common belief that metals do not behave like elastic-isotropic solids under shock compression

  1. 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...

  2. A novel magnetic valve using room temperature magnetocaloric materials

    DEFF Research Database (Denmark)

    Eriksen, Dan; Bahl, Christian; Pryds, Nini

    2012-01-01

    changes. This is made possible by the strong temperature dependence of the magnetization close to the Curie temperature of the magnetocaloric materials. Different compositions of both La0.67(Ca,Sr)0.33MnO3 and La(Fe,Co,Si)13 have been considered for use in prototype valves. Based on measured magnetization...

  3. 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)

  4. 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)

  5. 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...

  6. 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

  7. 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...

  8. Thermomechanical process optimization of U-10 wt% Mo – Part 1: high-temperature compressive properties and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Vineet V., E-mail: vineet.joshi@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Nyberg, Eric A.; Lavender, Curt A.; Paxton, Dean [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Garmestani, Hamid [Georgia Institute of Technology, Atlanta, GA 30332 (United States); Burkes, Douglas E. [Pacific Northwest National Laboratory, Richland, WA 99354 (United States)

    2015-10-15

    Nuclear power research facilities require alternatives to existing highly enriched uranium alloy fuel. One option for a high density metal fuel is uranium alloyed with 10 wt% molybdenum (U–10Mo). Fuel fabrication process development requires specific mechanical property data that, to date has been unavailable. In this work, as-cast samples were compression tested at three strain rates over a temperature range of 400–800 °C to provide data for hot rolling and extrusion modeling. The results indicate that with increasing test temperature the U–10Mo flow stress decreases and becomes more sensitive to strain rate. In addition, above the eutectoid transformation temperature, the drop in material flow stress is prominent and shows a strain-softening behavior, especially at lower strain rates. Room temperature X-ray diffraction and scanning electron microscopy combined with energy dispersive spectroscopy analysis of the as-cast and compression tested samples were conducted. The analysis revealed that the as-cast samples and the samples tested below the eutectoid transformation temperature were predominantly γ phase with varying concentration of molybdenum, whereas the ones tested above the eutectoid transformation temperature underwent significant homogenization.

  9. Room temperature synthesis and high temperature frictional study of silver vanadate nanorods.

    Science.gov (United States)

    Singh, D P; Polychronopoulou, K; Rebholz, C; Aouadi, S M

    2010-08-13

    We report the room temperature (RT) synthesis of silver vanadate nanorods (consisting of mainly beta-AgV O(3)) by a simple wet chemical route and their frictional study at high temperatures (HT). The sudden mixing of ammonium vanadate with silver nitrate solution under constant magnetic stirring resulted in a pale yellow coloured precipitate. Structural/microstructural characterization of the precipitate through x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the high yield and homogeneous formation of silver vanadate nanorods. The length of the nanorods was 20-40 microm and the thickness 100-600 nm. The pH variation with respect to time was thoroughly studied to understand the formation mechanism of the silver vanadate nanorods. This synthesis process neither demands HT, surfactants nor long reaction time. The silver vanadate nanomaterial showed good lubrication behaviour at HT (700 degrees C) and the friction coefficient was between 0.2 and 0.3. HT-XRD revealed that AgV O(3) completely transformed into silver vanadium oxide (Ag(2)V(4)O(11)) and silver with an increase in temperature from RT to 700 degrees C.

  10. Room temperature synthesis and high temperature frictional study of silver vanadate nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D P; Aouadi, S M [Department of Physics, Southern Illinois University, Carbondale-62901 (United States); Polychronopoulou, K [Department of Chemistry, University of Cyprus, Nicosia, 1678 (Cyprus); Rebholz, C, E-mail: dineshpsingh@gmail.com, E-mail: saouadi@physics.siu.edu [Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, 1678 (Cyprus)

    2010-08-13

    We report the room temperature (RT) synthesis of silver vanadate nanorods (consisting of mainly {beta}-AgV O{sub 3}) by a simple wet chemical route and their frictional study at high temperatures (HT). The sudden mixing of ammonium vanadate with silver nitrate solution under constant magnetic stirring resulted in a pale yellow coloured precipitate. Structural/microstructural characterization of the precipitate through x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the high yield and homogeneous formation of silver vanadate nanorods. The length of the nanorods was 20-40 {mu}m and the thickness 100-600 nm. The pH variation with respect to time was thoroughly studied to understand the formation mechanism of the silver vanadate nanorods. This synthesis process neither demands HT, surfactants nor long reaction time. The silver vanadate nanomaterial showed good lubrication behaviour at HT (700 deg. C) and the friction coefficient was between 0.2 and 0.3. HT-XRD revealed that AgV O{sub 3} completely transformed into silver vanadium oxide (Ag{sub 2}V{sub 4}O{sub 11}) and silver with an increase in temperature from RT to 700 deg. C.

  11. 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.

  12. Room-temperature ferromagnetism in Dy films doped with Ni

    Energy Technology Data Exchange (ETDEWEB)

    Edelman, I. [Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036 (Russian Federation)], E-mail: ise@iph.krasn.ru; Ovchinnikov, S. [Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Siberian Federal University, Av. Svobodnyi 71, Krasnoyarsk 660074 (Russian Federation); Markov, V.; Kosyrev, N.; Seredkin, V.; Khudjakov, A.; Bondarenko, G. [Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Kesler, V. [Institute of Semiconductor Physics, Siberian Division, Russian Academy of Sciences, Av. Akademika Lavrent' eva 13, Novosibirsk 630090 (Russian Federation)

    2008-09-01

    Temperature, magnetic field and spectral dependences of magneto-optical effects (MOEs) in bi-layer films Dy{sub (1-x)}Ni{sub x}-Ni and Dy{sub (1-x)}(NiFe){sub x}-NiFe were investigated, x changes from 0 to 0.06. Peculiar behavior of the MOEs was revealed at temperatures essentially exceeding the Curie temperature of bulk Dy which is explained by the magnetic ordering of the Dy layer containing Ni under the action of two factors: Ni impurities distributed homogeneously over the whole Dy layer and atomic contact of this layer with continues Ni layer. The mechanism of the magnetic ordering is suggested to be associated with the change of the density of states of the alloy Dy{sub (1-x)}Ni{sub x} owing to hybridization with narrow peaks near the Fermi level character for Ni.

  13. Room-temperature ferromagnetism in Dy films doped with Ni

    International Nuclear Information System (INIS)

    Edelman, I.; Ovchinnikov, S.; Markov, V.; Kosyrev, N.; Seredkin, V.; Khudjakov, A.; Bondarenko, G.; Kesler, V.

    2008-01-01

    Temperature, magnetic field and spectral dependences of magneto-optical effects (MOEs) in bi-layer films Dy (1-x) Ni x -Ni and Dy (1-x) (NiFe) x -NiFe were investigated, x changes from 0 to 0.06. Peculiar behavior of the MOEs was revealed at temperatures essentially exceeding the Curie temperature of bulk Dy which is explained by the magnetic ordering of the Dy layer containing Ni under the action of two factors: Ni impurities distributed homogeneously over the whole Dy layer and atomic contact of this layer with continues Ni layer. The mechanism of the magnetic ordering is suggested to be associated with the change of the density of states of the alloy Dy (1-x) Ni x owing to hybridization with narrow peaks near the Fermi level character for Ni

  14. Model predictive control of room temperature with disturbance compensation

    Science.gov (United States)

    Kurilla, Jozef; Hubinský, Peter

    2017-08-01

    This paper deals with temperature control of multivariable system of office building. The system is simplified to several single input-single output systems by decoupling their mutual linkages, which are separately controlled by regulator based on generalized model predictive control. Main part of this paper focuses on the accuracy of the office temperature with respect to occupancy profile and effect of disturbance. Shifting of desired temperature and changing of weighting coefficients are used to achieve the desired accuracy of regulation. The final structure of regulation joins advantages of distributed computing power and possibility to use network communication between individual controllers to consider the constraints. The advantage of using decoupled MPC controllers compared to conventional PID regulators is demonstrated in a simulation study.

  15. 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.

  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. 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.

  18. 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...

  19. 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.

  20. Investigation on compression behaviour of highly compacted GMZ01 bentonite with suction and temperature control

    Energy Technology Data Exchange (ETDEWEB)

    Ye, W.M., E-mail: ye_tju@tongji.edu.cn [Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092 (China); United Research Center for Urban Environment and Sustainable Development, The Ministry of Education, Shanghai 200092 (China); Zhang, Y.W.; Chen, B.; Zheng, Z.J.; Chen, Y.G. [Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092 (China); Cui, Y.J. [Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092 (China); Ecole des Ponts ParisTech, UR Navier/CERMES 77455 (France)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Heating induced volumetric change of GMZ01 bentonite depends on suction. Black-Right-Pointing-Pointer Suction has significant influence on compressibility. Black-Right-Pointing-Pointer Temperature has slight influence on compressibility. - Abstract: In this paper, an oedometer with suction and temperature control was developed. Mechanical compaction tests have been performed on the highly compacted GMZ01 bentonite, which has been recognized as potential buffer/backfill material for construction of Chinese high-level radioactive waste (HLW) geological repository, under conditions of suction ranging from 0 to 110 MPa, temperature from 20 to 80 Degree-Sign C and vertical pressure from 0.1 to 80 MPa. Based on the test results, suction and temperature effects on compressibility parameters are investigated. Results reveal that: (1) at high suctions, heating induced an expansion, while contraction is induced by heating at low suctions. The thermal expansion coefficient of GMZ01 bentonite measured is 1 Multiplication-Sign 10{sup -4} Degree-Sign C{sup -1}; (2) with increasing suction, the elastic compressibility {kappa} and the plastic compressibility {lambda}(s) of the highly compacted GMZ01 bentonite decrease, while the pre-consolidation pressure increases markedly; (3) with increasing temperature, the elastic compressibility of compacted GMZ01 bentonite changes insignificantly, while the plastic compressibility {lambda}(s) slightly decreases and the yield surface tends to shrink.

  1. Investigation on compression behaviour of highly compacted GMZ01 bentonite with suction and temperature control

    International Nuclear Information System (INIS)

    Ye, W.M.; Zhang, Y.W.; Chen, B.; Zheng, Z.J.; Chen, Y.G.; Cui, Y.J.

    2012-01-01

    Highlights: ► Heating induced volumetric change of GMZ01 bentonite depends on suction. ► Suction has significant influence on compressibility. ► Temperature has slight influence on compressibility. - Abstract: In this paper, an oedometer with suction and temperature control was developed. Mechanical compaction tests have been performed on the highly compacted GMZ01 bentonite, which has been recognized as potential buffer/backfill material for construction of Chinese high-level radioactive waste (HLW) geological repository, under conditions of suction ranging from 0 to 110 MPa, temperature from 20 to 80 °C and vertical pressure from 0.1 to 80 MPa. Based on the test results, suction and temperature effects on compressibility parameters are investigated. Results reveal that: (1) at high suctions, heating induced an expansion, while contraction is induced by heating at low suctions. The thermal expansion coefficient of GMZ01 bentonite measured is 1 × 10 −4 °C −1 ; (2) with increasing suction, the elastic compressibility κ and the plastic compressibility λ(s) of the highly compacted GMZ01 bentonite decrease, while the pre-consolidation pressure increases markedly; (3) with increasing temperature, the elastic compressibility of compacted GMZ01 bentonite changes insignificantly, while the plastic compressibility λ(s) slightly decreases and the yield surface tends to shrink.

  2. Strength and Permeability Evolution of Compressed Bentonite in Response to Salinity and Temperature Changes

    Science.gov (United States)

    Winnard, B. R.; Mitchell, T. M.; Browning, J.; Cuss, R. J.; Norris, S.; Meredith, P. G.

    2017-12-01

    Deep geological repositories are the preferred solution to dispose of radioactive waste; design concepts for these disposal facilities include compacted, saturated bentonite as a buffer between waste canister and host rock. Bentonite is favoured for its high swelling capacity, low permeability, and radionuclide retention properties. However, its thermo-hydro-mechanical tolerances must be thoroughly tested to ensure adequate long term performance. Climate variations are likely to induce periods of permafrost, and consequently, changes in groundwater salinity at depth. We performed laboratory experiments investigating effects of temperature and salinity change on uniaxial compressive strength (UCS), and permeability of compacted MX-80 bentonite cylinders. These specimens (moisture content = 22.9±0.1%, dry density = 1.66±0.02 g.cm-3) were compacted with deionised water, and a range of wt% NaCl, CaCl2, or KCl, to compare the effects of compaction fluid. Samples of compressed bentonite were cooled to -20 °C, and heated to 90 ºC, a possible temperature forecast for a repository dependent on factors such as geographical location, waste type, and facility design. Tests were all performed at room temperature, however in situ temperature tests are planned. The UCS of samples that experienced freeze thaw, and 40 ºC treatment failed at 6.5 MPa, with 4% strain, maintaining the same values as untreated bentonite compacted with deionised water. Samples compacted with saline solutions also yielded similar strengths, of 7 MPa, and failed at 4%. However, the 90 ºC, regardless of compaction fluid, failed at 15-18 MPa, at just 2% strain. In all experiments, the spread of strain accommodated varied inconsistently, however, peak stress was uniform. Further experiments into heterogeneity are needed to understand the responsible mechanisms. To obtain permeability, we utilised the pore pressure oscillation (PPO) technique with argon as the pore fluid. We also tested water as the pore

  3. Neutron scattering experiments of the ionic crystal deformed plastically with uniaxial compression under high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Yoshinori; Minakawa, Nobuaki; Aizawa, Kazuya; Ozawa, Kunio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-04-01

    As an aim of huge growth of alkali halide (AH) single crystal, a mosaic structure of small size AH single crystal deformed plastically with uniaxial compression under high temperature was evaluated due to its neutron irradiation experiment. Using TAS-2 installed at JRR-3M guide hole of Japan Atomic Energy Research Institute, locking curve at a representative face factor of the specimen was measured to observe the mosaic structure accompanied with expansion of the crystal due to compression. As a result, though the specimen before compression could be supposed to be divided to some parts already, the locking curve under 10 sec. of compression time showed already some fracture to divisions to suppose finer degradation of the crystal, and division of the locking curve at 600 sec. of compression time could be observed onto its 220 face. And, every compressed specimens showed some changes of crystallization method from standard sample. (G.K.)

  4. The effects of heated and room-temperature abdominal lavage solutions on core body temperature in dogs undergoing celiotomy.

    Science.gov (United States)

    Nawrocki, Michael A; McLaughlin, Ron; Hendrix, P K

    2005-01-01

    To document the magnitude of temperature elevation obtained with heated lavage solutions during abdominal lavage, 18 dogs were lavaged with sterile isotonic saline intraoperatively (i.e., during a celiotomy). In nine dogs, room-temperature saline was used. In the remaining nine dogs, saline heated to 43+/-2 degrees C (110+/-4 degrees F) was used. Esophageal, rectal, and tympanic temperatures were recorded every 60 seconds for 15 minutes after initiation of the lavage. Temperature levels decreased in dogs lavaged with room-temperature saline. Temperature levels increased significantly in dogs lavaged with heated saline after 2 to 6 minutes of lavage, and temperatures continued to increase throughout the 15-minute lavage period.

  5. FINAL REPORT: Room Temperature Hydrogen Storage in Nano-Confined Liquids

    Energy Technology Data Exchange (ETDEWEB)

    VAJO, JOHN

    2014-06-12

    DOE continues to seek solid-state hydrogen storage materials with hydrogen densities of ≥6 wt% and ≥50 g/L that can deliver hydrogen and be recharged at room temperature and moderate pressures enabling widespread use in transportation applications. Meanwhile, development including vehicle engineering and delivery infrastructure continues for compressed-gas hydrogen storage systems. Although compressed gas storage avoids the materials-based issues associated with solid-state storage, achieving acceptable volumetric densities has been a persistent challenge. This project examined the possibility of developing storage materials that would be compatible with compressed gas storage technology based on enhanced hydrogen solubility in nano-confined liquid solvents. These materials would store hydrogen in molecular form eliminating many limitations of current solid-state materials while increasing the volumetric capacity of compressed hydrogen storage vessels. Experimental methods were developed to study hydrogen solubility in nano-confined liquids. These methods included 1) fabrication of composites comprised of volatile liquid solvents for hydrogen confined within the nano-sized pore volume of nanoporous scaffolds and 2) measuring the hydrogen uptake capacity of these composites without altering the composite composition. The hydrogen storage capacities of these nano-confined solvent/scaffold composites were compared with bulk solvents and with empty scaffolds. The solvents and scaffolds were varied to optimize the enhancement in hydrogen solubility that accompanies confinement of the solvent. In addition, computational simulations were performed to study the molecular-scale structure of liquid solvent when confined within an atomically realistic nano-sized pore of a model scaffold. Confined solvent was compared with similar simulations of bulk solvent. The results from the simulations were used to formulate a mechanism for the enhanced solubility and to guide the

  6. 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....

  7. Creep and creep recovery of concrete subjected to triaxial compressive stresses at elevated temperature

    International Nuclear Information System (INIS)

    Ohnuma, Hiroshi; Abe, Hirotoshi

    1979-01-01

    In order to design rationally the vessels made of prestressed concrete for nuclear power stations and to improve the accuracy of high temperature creep analysis, the Central Research Institute of Electric Power Industry had carried out the proving experiments with scale models. In order to improve the accuracy of analysis, it is important to grasp the creep behavior of the concrete subjected to triaxial compressive stresses at high temperature as the basic property of concrete, because actual prestressed concrete vessels are in such conditions. In this paper, the triaxial compression creep test at 60 deg. C using the concrete specimens with same mixing ratio as the scale models is reported. The compressive strength of the concrete at the age of 28 days was 406 kg/cm 2 , and the age of the concrete at the time of loading was 63 days. Creep and creep recovery were measured for 5 months and 2 months, respectively. The creep of concrete due to uniaxial compression increased with temperature rise, and the creep strain at 60 deg. C was 2.54 times as much as that at 20 deg. C. The effective Poisson's ratio in triaxial compression creep was 0.15 on the average, based on the creep strain due to uniaxial compression at 60 deg. C. The creep recovery rate in high temperature, triaxial compression creep was 33% on the average. (Kako, I.)

  8. 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.

  9. 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.

  10. Apparatus to measure vapor pressure, differential vapor pressure, liquid molar volume, and compressibility of liquids and solutions to the critical point. Vapor pressures, molar volumes, and compressibilities of protiobenzene and deuteriobenzene at elevated temperatures

    International Nuclear Information System (INIS)

    Kooner, Z.S.; Van Hook, W.A.

    1986-01-01

    An apparatus designed to measure vapor pressure differences between two similar liquids, such as isotopic isomers, or between a solution and its reference solvent at temperatures and pressures extending to the critical point is described. Vapor-phase volume is minimized and pressure is transmitted to the transducer through the liquid, thereby avoiding several experimental difficulties. Liquid can be injected into the heated part of the system by volumetrically calibrated screw injectors, thus permitting measurements of liquid molar volume, compressibility, and expansivity. The addition of a high-pressure circulating pump and injection valve allows the apparatus to be employed as a continuous dilution differential vapor pressure apparatus for determining partial molar free energies of solution. In the second part of the paper data on the vapor pressure, molar volume, compressibility, and expansivity and their isotope effects for C 6 H 6 and C 6 D 6 from room temperature to near the critical temperature are reported

  11. 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.

  12. 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, ...

  13. Room temperature synthesis of water-repellent polystyrene nanocomposite coating

    International Nuclear Information System (INIS)

    Guo Yonggang; Jiang Dong; Zhang Xia; Zhang Zhijun; Wang Qihua

    2010-01-01

    A stable superhydrophobic polystyrene nanocomposite coating was fabricated by means of a very simple and easy method. The coating was characterized by scanning electron microscopy and X-ray photoelectron spectrum. The wettability of the products was also investigated. By adding the surface-modified SiO 2 nanoparticles, the wettability of the coating changed to water-repellent superhydrophobic, not only for pure water, but also for a wide pH range of corrosive liquids. The influence of the drying temperature and SiO 2 content on the wettability of the nanocomposite coating was also investigated. It was found that both factors had little or no significant effect on the wetting behavior of the coating surface.

  14. Room-temperature-deposited dielectrics and superconductors for integrated photonics.

    Science.gov (United States)

    Shainline, Jeffrey M; Buckley, Sonia M; Nader, Nima; Gentry, Cale M; Cossel, Kevin C; Cleary, Justin W; Popović, Miloš; Newbury, Nathan R; Nam, Sae Woo; Mirin, Richard P

    2017-05-01

    We present an approach to fabrication and packaging of integrated photonic devices that utilizes waveguide and detector layers deposited at near-ambient temperature. All lithography is performed with a 365 nm i-line stepper, facilitating low cost and high scalability. We have shown low-loss SiN waveguides, high-Q ring resonators, critically coupled ring resonators, 50/50 beam splitters, Mach-Zehnder interferometers (MZIs) and a process-agnostic fiber packaging scheme. We have further explored the utility of this process for applications in nonlinear optics and quantum photonics. We demonstrate spectral tailoring and octave-spanning supercontinuum generation as well as the integration of superconducting nanowire single photon detectors with MZIs and channel-dropping filters. The packaging approach is suitable for operation up to 160 °C as well as below 1 K. The process is well suited for augmentation of existing foundry capabilities or as a stand-alone process.

  15. Continuous wave room temperature external ring cavity quantum cascade laser

    Energy Technology Data Exchange (ETDEWEB)

    Revin, D. G., E-mail: d.revin@sheffield.ac.uk; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W. [Physics and Astronomy Department, The University of Sheffield, S3 7RH Sheffield (United Kingdom); Hempler, N.; Maker, G. T.; Malcolm, G. P. A. [M Squared Lasers Ltd., G20 0SP Glasgow (United Kingdom)

    2015-06-29

    An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm{sup −1} is realized by the incorporation of a diffraction grating into the cavity.

  16. Continuous wave room temperature external ring cavity quantum cascade laser

    International Nuclear Information System (INIS)

    Revin, D. G.; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W.; Hempler, N.; Maker, G. T.; Malcolm, G. P. A.

    2015-01-01

    An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm −1 is realized by the incorporation of a diffraction grating into the cavity

  17. Synthesis and characterization of strontium carboxylates at room temperature and at high temperature in autoclave vessels

    DEFF Research Database (Denmark)

    Christgau, Stephan; Ståhl, Kenny; Andersen, Jens Enevold Thaulov

    2006-01-01

    A novel method was developed for synthesis of strontium coordination compounds in high yields. The synthesis proceeded along three pathways that provided strontium salts in high purity and high yields, close to 100%, as confirmed by flame atomic absorption spectroscopy (FAAS) and powder x......-ray crystallography. Optimum conditions were found at T = 120-1400C, a base-to-acid ratio of 1.2 and 15 min. of reaction-time in an autoclave vessel. Large crystals were readily obtained within a time period of hours. The crystal structures of strontium D-glutamate hexahydrate (I) and strontium di-(hydrogen L......-glutamate) pentahydrate (II) were confirmed by X-ray powder diffraction at 295 K and Rietveld refinements (I: Space group P212121, Z=4, a=7.3519(2), b=8.7616(2), c=20.2627(5) Å, and II: Space group P21, Z=2, a=8.7243(1), b=7.2635(1), c=14.6840(2) Å, β=100.5414(7) °). Synthesis at room temperature provided four additional...

  18. 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

  19. FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment.

    Science.gov (United States)

    Zhang, Tao; Jiang, Feng; Yan, Lan; Xu, Xipeng

    2017-12-26

    The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM) model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE) simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

  20. FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment

    Directory of Open Access Journals (Sweden)

    Tao Zhang

    2017-12-01

    Full Text Available The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

  1. 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

  2. Formation of crystalline telluridomercurates from ionic liquids near room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Donsbach, Carsten; Dehnen, Stefanie [Fachbereich Chemie und Wissenschaftliches Zentrum fuer Materialwissenschaften, Philipps-Universitaet Marburg, Hans-Meerwein-Strasse 4, 35043, Marburg (Germany)

    2017-01-15

    The ternary telluridomercurate Na{sub 2}[HgTe{sub 2}] (1) was formed by fusion of Na{sub 2}Te and HgTe at 600 C and further treated in the ionic liquid (C{sub 4}C{sub 1}Im)[BF{sub 4}] (C{sub 4}C{sub 1}Im = 1-butyl-3-methylimidazolium) at moderately elevated temperatures (60 C), leading to replacement of the Na{sup +} cations with (C{sub 4}C{sub 1}Im){sup +} and re-arrangement of the inorganic substructure. As a result, we obtained the telluridomercurate (C{sub 4}C{sub 1}Im){sub 2}[HgTe{sub 2}] (2) and the tellurido/ditelluridomercurate (C{sub 4}C{sub 1}Im){sub 2}[Hg{sub 2}Te{sub 4}] (3) besides polytellurides and HgTe as by-products. The heavy atom compositions of the compounds were confirmed by micro X-ray fluorescence spectroscopy (μ-XFS), and their structures were determined by single-crystal diffraction. The cation-exchanged salts were further investigated by UV/Vis spectroscopy, indicating narrow band-gap optical transitions at 2.80 eV (2) and 1.63 eV (3), in agreement with their visible yellow or reddish-black color, respectively. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Effect of warm compress application on tissue temperature in healthy dogs.

    Science.gov (United States)

    Millard, Ralph P; Towle-Millard, Heather A; Rankin, David C; Roush, James K

    2013-03-01

    To measure the effect of warm compress application on tissue temperature in healthy dogs. 10 healthy mixed-breed dogs. Dogs were sedated with hydromorphone (0.1 mg/kg, IV) and diazepam (0.25 mg/kg, IV). Three 24-gauge thermocouple needles were inserted to a depth of 0.5 cm (superficial), 1.0 cm (middle), and 1.5 cm (deep) into a shaved, lumbar, epaxial region to measure tissue temperature. Warm (47°C) compresses were applied with gravity dependence for periods of 5, 10, and 20 minutes. Tissue temperature was recorded before compress application and at intervals for up to 80 minutes after application. Control data were collected while dogs received identical sedation but with no warm compress. Mean temperature associated with 5 minutes of heat application at the superficial, middle, and deep depths was significantly increased, compared with the control temperature. Application for 10 minutes significantly increased the temperature at all depths, compared with 5 minutes of application. Mean temperature associated with 20 minutes of application was not different at the superficial or middle depths, compared with 10 minutes of application. Temperature at the deep depth associated with 10 minutes of application was significantly higher, compared with 20 minutes of application, but all temperature increases at this depth were minimal. Results suggested that application of a warm compress should be performed for 10 minutes. Changes in temperature at a tissue depth of 1.5 cm were minimal or not detected. The optimal compress temperature to achieve therapeutic benefits was not determined.

  4. Microstructure and Room-Temperature Mechanical Properties of FeCrMoVTi x High-Entropy Alloys

    Science.gov (United States)

    Guo, Jun; Huang, Xuefei; Huang, Weigang

    2017-07-01

    FeCrMoVTi x ( x values represent the molar ratio, where x = 0, 0.5, 1.0, 1.5, and 2.0) high-entropy alloys were prepared by a vacuum arc melting method. The effects of Ti element on the microstructure and room-temperature mechanical properties of the as-cast FeCrMoVTi x alloys were investigated. The results show that the prepared alloys exhibited typical dendritic microstructure and the size of the microstructure became fine with increasing Ti content. The FeCrMoV alloy exhibited a single body-centered cubic structure (BCC1) and the alloys prepared with Ti element exhibited BCC1 + BCC2 mixed structure. The new BCC2 phase is considered as (Fe, Ti)-rich phase and was distributed in the dendrite region. With the increase of Ti content, the volume fraction of the BCC2 phase increased and its shape changed from a long strip to a network. For the FeCrMoV alloy, the fracture strength, plastic strain, and hardness reached as high as 2231 MPa, 28.2%, and 720 HV, respectively. The maximum hardness of 887 HV was obtained in the FeCrMoVTi alloy. However, the fracture strength, yield stress, and plastic strain of the alloys decreased continuously as Ti content increased. In the room-temperature compressive test, the alloys showed typical brittle fracture characteristics.

  5. An investigation of dynamic mechanical behaviour of Ti6Al4V titanium alloy at room temperature

    Directory of Open Access Journals (Sweden)

    Ran Chun

    2016-01-01

    Full Text Available To study the high strain rate shear behaviour of Ti6Al4V titanium alloy, a series of dynamic compression experiments has been performed by split Hopkinson pressure bar (SHPB using Flat Hat-shaped specimen at room temperature. Macro true shear stress-true strain curves were obtained under different strain rate loading conditions at room temperature. The effects of strain hardening and strain rate hardening on the dynamic mechanical properties of Ti6Al4V titanium alloy were discussed. Results indicate that a The higher the strain rate, the higher the flow stress, therefore, the material has obvious strain rate hardening effect, b It is ductile failure for Ti6Al4V titanium alloy under quasi-static loading condition, c For dynamical tests, the values for true shear stress increase with increasing true strain till the maximum true shear stress, on the contrary, the values for true shear stress decrease with increasing the true strain after the maximum true shear stress and d The flow stress increases with increasing the true strain under quasi-static loading condition during the plastic deformation.

  6. 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.

  7. Towards room-temperature performance for lithium-polymer batteries

    International Nuclear Information System (INIS)

    Kerr, J.B.; Liu, Gao; Curtiss, L.A.; Redfern, Paul C.

    2003-01-01

    Recent work on molecular simulations of the mechanisms of lithium ion conductance has pointed towards two types of limiting process. One has involved the commonly cited segmental motion while the other is related to energy barriers in the solvation shell of polymeric ether oxygens around the lithium ions. Calculations of the barriers to lithium ion migration have provided important indicators as to the best design of the polymer. The theoretical work has coincided with and guided some recent developments on polymer synthesis for lithium batteries. Structural change of the polymer solvation shell has been pursued by the introduction of trimethylene oxide (TMO) units into the polymer. The conductivity measurements on polymers containing TMO unit are encouraging. The architecture of the polymer networks has been varied upon which the solvating groups are attached and significant improvements in sub-ambient performance are observed as a result. However, the above-ambient temperature performance appears controlled by an Arrhenius process that is not completely consistent with the theoretical calculations described here and may indicate the operation of a different mechanism. The new polymers possess significantly lower T g values in the presence of lithium salts, which indicates weaker binding of the lithium ions by the polymers. These properties provide considerable improvement in the transport properties close to the electrode surfaces resulting in decreased impedances at the surfaces both at lithium metal and in composite electrodes. The greater flexibility of the solvation groups combined with appropriate architecture not only has applications in lithium metal-polymer batteries but also in lithium ion liquid and gel systems as well as in fuel cell electrodes

  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. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Method for compression molding of thermosetting plastics utilizing a temperature gradient across the plastic to cure the article

    Science.gov (United States)

    Heier, W. C. (Inventor)

    1974-01-01

    A method is described for compression molding of thermosetting plastics composition. Heat is applied to the compressed load in a mold cavity and adjusted to hold molding temperature at the interface of the cavity surface and the compressed compound to produce a thermal front. This thermal front advances into the evacuated compound at mean right angles to the compression load and toward a thermal fence formed at the opposite surface of the compressed compound.

  15. Mechanical vapor compression refrigeration for low temperature industrial applications today

    International Nuclear Information System (INIS)

    Ferguson, J.E.

    1987-01-01

    If the super conductor industry settles out at a temperature of -100 0 F or above, mechanical refrigeration will be vying for the cooling business. Today there very definitely is a break point in the application of equipment at approximately -120 0 F or 189 0 K. Other technologies are generally utilized below this level. However, with market potential comes invention and breakthroughs in refrigeration can also occur. Today standard refrigeration systems are cost effective, reliable and produced in the millions for high temperature applications of +10 0 F to +40 0 F evaporator temperature. Lower temperatures require additional hardware, consume additional power and are produced today in limited quantities for special applications

  16. Effect of cold compress application on tissue temperature in healthy dogs.

    Science.gov (United States)

    Millard, Ralph P; Towle-Millard, Heather A; Rankin, David C; Roush, James K

    2013-03-01

    To measure the effect of cold compress application on tissue temperature in healthy dogs. 10 healthy mixed-breed dogs. Dogs were sedated with hydromorphone (0.1 mg/kg, IV) and diazepam (0.25 mg/kg, IV). Three 24-gauge thermocouple needles were inserted to a depth of 0.5 (superficial), 1.0 (middle), and 1.5 (deep) cm into a shaved, lumbar, epaxial region to measure tissue temperature. Cold (-16.8°C) compresses were applied with gravity dependence for periods of 5, 10, and 20 minutes. Tissue temperature was recorded before compress application and at intervals for up to 80 minutes after application. Control data were collected while dogs received identical sedation but with no cold compress. Mean temperature associated with 5 minutes of application at the superficial depth was significantly decreased, compared with control temperatures. Application for 10 and 20 minutes significantly reduced the temperature at all depths, compared with controls and 5 minutes of application. Twenty minutes of application significantly decreased temperature at only the middle depth, compared with 10 minutes of application. With this method of cold treatment, increasing application time from 10 to 20 minutes caused a further significant temperature change at only the middle tissue depth; however, for maximal cooling, the minimum time of application should be 20 minutes. Possible changes in tissue temperature and adverse effects of application > 20 minutes require further evaluation.

  17. 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

  18. 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...

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. Experimental study under uniaxial cyclic behavior at room and high temperature of 316L stainless steel

    International Nuclear Information System (INIS)

    Kang Guozheng; Gao Qing; Yang Xianjie; Sun Yafang

    2001-01-01

    An experimental study was carried out of the cyclic properties of 316L stainless steel subjected to uniaxial strain and stress at room and high temperature. The effects of cyclic strain amplitude, temperature and their histories on the cyclic deformation behavior of 316L stainless steel are investigated. And, the influences of stress amplitude, mean stress, temperature and their histories on ratcheting are also analyzed. It is shown that either uniaxial cyclic property under cyclic strain or ratcheting under asymmetric uniaxial cyclic stress depends not only on the current temperature and loading state, but also on the previous temperature and loading history. Some significant results are obtained

  8. Elastic and strength properties of Hanford concrete mixes at room and elevated temperatures

    International Nuclear Information System (INIS)

    Abrams, M.S.; Gillen, M.; Campbell, D.H.

    1979-03-01

    The effects of long-term exposure to elevated temperatures on the physical properties of concrete mixes used in Hanford radioactive waste storage tanks were determined. Temperature had a significant effect on the elastic modulus of concretes. Poisson's ratio determined by the sonic method remained relatively constant. The splitting tensile strength increased rapidly up to 190 days of age. Then strength decreased to about 350 days and either leveled off or increased from that point on. Compressive strength data were erratic

  9. Structure of boron nitride after the high-temperature shock compression

    International Nuclear Information System (INIS)

    Kurdyumov, A.V.; Ostrovskaya, N.F.; Pilipenko, V.A.; Pilyankevich, A.N.; Savvakin, G.I.; Trefilov, V.I.

    1979-01-01

    Boron nitride structure changes as a result of high temperature dynamic compression are studied. The X-ray technique and transmission electron microscopy have been applied. The data on the structure and regularities of formation of diamond-like modifications of boron nitride at high temperature impact compression permit to consider martensite transformation as the first stage of formation of the sphalerite phase stable at high pressures. The second stage is possible if the temperature at the impact moment is sufficiently high for intensive diffusion processes

  10. 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

  11. 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.

  12. 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.

  13. Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control

    Energy Technology Data Exchange (ETDEWEB)

    Sakaguchi, S., E-mail: sakaguchi@phys.kyushu-u.ac.jp [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Uesaka, T. [RIKEN Nishina Center, Saitama 351-0198 (Japan); Kawahara, T. [Department of Physics, Toho University, Chiba 274-8510 (Japan); Ogawa, T. [RIKEN Advanced Science Institute, Saitama 351-0198 (Japan); Tang, L. [Center for Nuclear Study, University of Tokyo, Tokyo 113-0001 (Japan); Teranishi, T. [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Urata, Y.; Wada, S. [RIKEN Advanced Science Institute, Saitama 351-0198 (Japan); Wakui, T. [Cyclotron and Radioisotope Center (CYRIC), Tohoku University, Miyagi 980-8578 (Japan)

    2013-12-15

    Highlights: • Proton polarization in p-terphenyl at room-temperature is enhanced by a factor of 3. • Intense laser and temperature control are critically important for high polarization. • Optimization of time structure of laser pulse is effective for further improvement. -- Abstract: Proton polarization at room temperature, produced in a p-terphenyl crystal by using electron population difference in a photo-excited triplet state of pentacene, was enhanced by utilizing an intense laser with an average power of 1.5 W. It was shown that keeping the sample temperature below 300 K is critically important to prevent the rise of the spin–lattice relaxation rate caused by the laser heating. It is also reported that the magnitude of proton polarization strongly depends on the time structure of the laser pulse such as its width and the time interval between them.

  14. effect of elevated temperature on the compressive strength

    African Journals Online (AJOL)

    HOD

    reducing cost whilst maintaining structural integrity. [1–4].The solid ... density and surface appearance are affected by temperature .... Table 1: Physical properties of Sand, Granite, cement .... The relationship between weight loss and elevated.

  15. 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.

  16. 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)

  17. 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

  18. 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

  19. 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...

  20. 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

  1. 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.

  2. 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

  3. 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...

  4. 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)

  5. 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)

  6. 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....

  7. 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...

  8. 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.)

  9. 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

  10. 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...

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.)

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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 ...

  7. 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...

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. Experimental data of the static behavior of reinforced concrete beams at room and low temperature.

    Science.gov (United States)

    Mirzazadeh, M Mehdi; Noël, Martin; Green, Mark F

    2016-06-01

    This article provides data on the static behavior of reinforced concrete at room and low temperature including, strength, ductility, and crack widths of the reinforced concrete. The experimental data on the application of digital image correlation (DIC) or particle image velocimetry (PIV) in measuring crack widths and the accuracy and precision of DIC/PIV method with temperature variations when is used for measuring strains is provided as well.

  13. 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...

  14. 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.

  15. 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

  16. 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

  17. Combustion Temperature Effect of Diesel Engine Convert to Compressed Natural Gas Engine

    OpenAIRE

    Semin; Abdul R. Ismail; Rosli A. Bakar

    2009-01-01

    Effect of combustion temperature in the engine cylinder of diesel engine convert to Compressed Natural Gas (CNG) engine was presents in this study. The objective of this study was to investigate the engine cylinder combustion temperature effect of diesel engine convert to CNG engine on variation engine speed. Problem statement: The hypothesis was that the lower performance of CNG engine was caused by the effect of lower in engine cylinder temperature. Are the CNG engine is lower cylinder temp...

  18. 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)

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Ratchetting behavior of type 304 stainless steel at room and elevated temperatures

    International Nuclear Information System (INIS)

    Ruggles, M.; Krempl, E.

    1988-01-01

    The zero-to-tension ratchetting behavior was investigated under uniaxial loading at room temperature and at 550, 600 and 650/degree/ C. In History I the maximum stress level of ratchetting was equal to the stress reached in a tensile test at one percent strain. For History II the maximum stress level was established as the stress reached after a 2100 s relaxation at one percent strain. Significant ratchetting was observed for History I at room temperature but not at the elevated temperatures. The accumulated ratchet strain increases with decreasing stress rate. Independent of the stress rates used insignificant ratchet strain was observed at room temperature for History II. This observation is explained in the context of the viscoplasticity theory based on overstress by the exhaustion of the viscous contribution to the stress during relaxation. The viscous part of the stress is the driving force for the ratchetting in History I. Strain aging is presumably responsible for the lack of short-time inelastic deformation resulting in a nearly rate-independent behavior at the elevated temperatures. 26 refs., 7 figs., 1 tab

  4. Compressibility, zero sound, and effective mass of a fermionic dipolar gas at finite temperature

    International Nuclear Information System (INIS)

    Kestner, J. P.; Das Sarma, S.

    2010-01-01

    The compressibility, zero-sound dispersion, and effective mass of a gas of fermionic dipolar molecules is calculated at finite temperature for one-, two-, and three-dimensional uniform systems, and in a multilayer quasi-two-dimensional system. The compressibility is nonmonotonic in the reduced temperature, T/T F , exhibiting a maximum at finite temperature. This effect might be visible in a quasi-low-dimensional experiment, providing a clear signature of the onset of many-body quantum degeneracy effects. The collective mode dispersion and effective mass show similar nontrivial temperature and density dependence. In a quasi-low-dimensional system, the zero-sound mode may propagate at experimentally attainable temperatures.

  5. The effect of reaction temperature on the room temperature ferromagnetic property of sol-gel derived tin oxide nanocrystal

    Science.gov (United States)

    Sakthiraj, K.; Hema, M.; Balachandra Kumar, K.

    2018-06-01

    In the present study, nanocrystalline tin oxide materials were prepared using sol-gel method with different reaction temperatures (25 °C, 50 °C, 75 °C & 90 °C) and the relation between the room temperature ferromagnetic property of the sample with processing temperature has been analysed. The X-ray diffraction pattern and infrared absorption spectra of the as-prepared samples confirm the purity of the samples. Transmission electron microscopy images visualize the particle size variation with respect to reaction temperature. The photoluminescence spectra of the samples demonstrate that luminescence process in materials is originated due to the electron transition mediated by defect centres. The room temperature ferromagnetic property is observed in all the samples with different amount, which was confirmed using vibrating sample magnetometer measurements. The saturation magnetization value of the as-prepared samples is increased with increasing the reaction temperature. From the photoluminescence & magnetic measurements we accomplished that, more amount of surface defects like oxygen vacancy and tin interstitial are created due to the increase in reaction temperature and it controls the ferromagnetic property of the samples.

  6. 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.

  7. Inhomogeneous dislocation structure in fatigued INCONEL 713 LC superalloy at room and elevated temperatures

    International Nuclear Information System (INIS)

    Petrenec, Martin; Obrtlik, Karel; Polak, Jaroslav

    2005-01-01

    The dislocations arrangement was studied using transmission electron microscopy in specimens of polycrystalline INCONEL 713 LC superalloy cyclically strained up to failure with constant total strain amplitudes at temperatures 300, 773, 973 and 1073 K. Planar dislocation arrangements in the form of bands parallel to the {1 1 1} planes were observed in specimens cycled at all the temperatures. The bands showed up as thin slabs of high dislocation density cutting both the γ channels and γ' precipitates. Ladder-like bands were observed at room temperature

  8. Cyclic plastic response of nickel-based superalloy at room and at elevated temperatures

    International Nuclear Information System (INIS)

    Polak, Jaroslav; Petrenec, Martin; Chlupova, Alice; Tobias, Jiri; Petras, Roman

    2015-01-01

    Nickel-based cast IN 738LC superalloy has been cycled at increasing strain amplitudes at room temperature and at 800 C. Hysteresis loops were analyzed using general statistical theory of the hysteresis loop. Dislocation structures of specimens cycled at these two temperatures were studied. They revealed localization of the cyclic plastic strain in the thin bands which are rich in dislocations. The analysis of the loop shapes yields effective stresses of the matrix and of the precipitates and the probability density function of the critical internal stresses at both temperatures. It allows to find the sources of the high cyclic stress.

  9. Design and Development of a Relative Humidity and Room Temperature Measurement System with On Line Data Logging Feature for Monitoring the Fermentation Room of Tea Factory

    Directory of Open Access Journals (Sweden)

    Utpal SARMA

    2011-12-01

    Full Text Available The design and development of a Relative Humidity (RH and Room Temperature (RT monitoring system with on line data logging feature for monitoring fermentation room of a tea factory is presented in this paper. A capacitive RH sensor with on chip signal conditioner is taken as RH sensor and a temperature to digital converter (TDC is used for ambient temperature monitoring. An 8051 core microcontroller is the heart of the whole system which reads the digital equivalent of RH data with the help of a 12-bit Analog to Digital (A/D converter and synchronize TDC to get the ambient temperature. The online data logging is achieved with the help of RS-232C communication. Field performance is also studied by installing it in the fermentation room of a tea factory.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Tension–compression asymmetry in an extruded Mg alloy AM30: Temperature and strain rate effects

    International Nuclear Information System (INIS)

    Zachariah, Z.; Tatiparti, Sankara Sarma V.; Mishra, S.K.; Ramakrishnan, N.; Ramamurty, U.

    2013-01-01

    The effect of strain rate, ε, and temperature, T, on the tension–compression asymmetry (TCA) in a dilute and wrought Mg alloy, AM30, over a temperature range that covers both twin accommodated deformation (below 250 °C in compression) as well as dislocation-mediated plasticity (above 250 °C) has been investigated. For this purpose, uniaxial tension and compression tests were conducted at T ranging from 25 to 400 °C with ε varying between 10 −2 and 10 s −1 . In most of the cases, the stress–strain responses in tension and compression are distinctly different; with compression responses ‘concaving upward,’ due to {101-bar 2} tensile twinning at lower plastic strains followed by slip and strain hardening at higher levels of deformation, for T below 250 °C. This results in significant levels of TCA at T −1 , suggesting that twin-mediated plastic deformation takes precedence at high rates of loading even at sufficiently high T. TCA becomes negligible at T=350 °C; however at T=400 °C, as ε increases TCA gets higher. Microscopy of the deformed samples, carried out by using electron back-scattered diffraction (EBSD), suggests that at T>250 °C dynamic recrystallization begins between accompanied by reduction in the twinned fraction that contributes to the decrease of the TCA

  19. Influence of Temperature on Workability and Compressive Strength of Ordinary Concrete with High Calcium Fly Ash

    Directory of Open Access Journals (Sweden)

    Gołaszewski Jacek

    2017-06-01

    Full Text Available The rheological properties of fresh ordinary concrete are closely affected by temperature and time. The paper presents the study of consistency of fresh concrete mixtures made with Portland cement and cement with calcareous fly ash. Two types of admixtures were used. It was proven that the temperature has a clear effect on workability and compressive strength concrete. Influence on workability can be reduced by selecting the appropriate superplasticizer and cement.

  20. Temperature measurement in a compressible flow field using laser-induced iodine fluorescence

    Science.gov (United States)

    Fletcher, D. G.; Mcdaniel, J. C.

    1987-01-01

    The thermometric capability of a two-line fluorescence technique using iodine seed molecules in air is investigated analytically and verified experimentally in a known steady compressible flow field. Temperatures ranging from 165 to 295 K were measured in the flowfield using two iodine transitions accessed with a 30-GHz dye-laser scan near 543 nm. The effect of pressure broadening on temperature measurement is evaluated.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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)

  6. A Fiber Bragg grating based tilt sensor suitable for constant temperature room

    International Nuclear Information System (INIS)

    Tang, Guoyu; Wei, Jue; Zhou, Wei; Wu, Mingyu; Yang, Meichao; Xie, Ruijun; Xu, Xiaofeng

    2015-01-01

    Constant-temperature rooms have been widely used in industrial production, quality testing, and research laboratories. This paper proposes a high-precision tilt sensor suitable for a constant- temperature room, which has achieved a wide-range power change while the fiber Bragg grating (FBG) reflection peak wavelength shifted very little, thereby demonstrating a novel method for obtaining a high-precision tilt sensor. This paper also studies the effect of the reflection peak on measurement precision. The proposed sensor can distinguish the direction of tilt with an excellent sensitivity of 403 dBm/° and a highest achievable resolution of 2.481 × 10 −5 ° (that is, 0.08% of the measuring range). (paper)

  7. 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.

  8. 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.

  9. 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)

  10. 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)

  11. 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).

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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)

  2. 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.

  3. 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...

  4. 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)

  5. 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.

  6. 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.

  7. 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.

  8. 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 )

  9. 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

  10. Room and elevated temperature Mechanical Behavior of 9-12% Cr Steels

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, Omer N.; Hawk, Jeffrey A.; Schrems, Karol K.

    2005-02-01

    The mechanical properties of medium Cr steels used in fossil fired power plants are very good because of their excellent high temperature microstructural stability. However, as the desire to increase the operating temperature (>650C) of the plant goes up, the need for steels that maintain their strength at these temperatures also increases. The mechanical properties of three medium Cr steels (0.08C-(9-12)Cr-1.2Ni-0.7Mo-3.0Cu-3.0Co-0.5Ti) were investigated through hardness, hot hardness and tensile measurements. The strength of the 9-12%Cr steels at room temperature after long-term isothermal aging (750C; 1000 hours) compares favorably with that of other power plant steels (e.g., P91). In addition, the elevated temperature strength and hot hardness also behave similarly. The mechanical behavior will be discussed in terms of the strength, elongation and tensile fracture characteristics.

  11. Room to high temperature measurements of flexible SOI FinFETs with sub-20-nm fins

    KAUST Repository

    Diab, Amer El Hajj

    2014-12-01

    We report the temperature dependence of the core electrical parameters and transport characteristics of a flexible version of fin field-effect transistor (FinFET) on silicon-on-insulator (SOI) with sub-20-nm wide fins and high-k/metal gate-stacks. For the first time, we characterize them from room to high temperature (150 °C) to show the impact of temperature variation on drain current, gate leakage current, and transconductance. Variation of extracted parameters, such as low-field mobility, subthreshold swing, threshold voltage, and ON-OFF current characteristics, is reported too. Direct comparison is made to a rigid version of the SOI FinFETs. The mobility degradation with temperature is mainly caused by phonon scattering mechanism. The overall excellent devices performance at high temperature after release is outlined proving the suitability of truly high-performance flexible inorganic electronics with such advanced architecture.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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...

  17. 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.

  18. 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.

  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. Two-Dimensional Metrology with Flatbed Scanners at Room and Liquid Nitrogen Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.; Grau Malonda, A. [CIEMAT. Madrid (Spain)

    2000-07-01

    We study the capability of the commercial flatbed scanner as a measuring instrument of two-coordinate sample both at room and liquid nitrogen temperatures. We describes simple procedure to calibrate the scanner, and the most adequate standard configuration to carry out the measurements. To illustrate the procedure, we measure the relative positions of the conductors in a cross-section of a superconducting magnet of CERN. (Author) 8 refs.

  9. Two-Dimensional Metrology with Flatbed Scanners at Room and Liquid Nitrogen Temperatures

    International Nuclear Information System (INIS)

    Grau Carles, A.; Grau Malonda, A.

    2000-01-01

    We study the capability of the commercial flatbed scanner as a measuring instrument of two-coordinate sample both at room and liquid nitrogen temperatures. We describes simple procedure to calibrate the scanner, and the most adequate standard configuration to carry out the measurements. To illustrate the procedure, we measure the relative positions of the conductors in a cross-section of a superconducting magnet of CERN. (Author) 8 refs

  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. 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...

  12. 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...

  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. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  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 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Tunable Curie temperature around room temperature and magnetocaloric effect in ternary Ce–Fe–B amorphous ribbons

    International Nuclear Information System (INIS)

    Li, Zhu-bai; Zhang, Le-le; Zhang, Xue-feng; Li, Yong-feng; Zhao, Qian; Zhao, Tong-yun; Shen, Bao-gen

    2017-01-01

    Ce 13−x Fe 81+x B 6 ( x   =  0, 0.5, 1, 1.5, and 2) amorphous magnets were prepared by melt-spinning method. These magnets are magnetically soft at low temperature, and undergo a second-order phase transition from ferromagnetic to paramagnetic state near room temperature with a broad temperature span. The phase-transition temperature is tunable by the variation of the Ce/Fe atomic ratio, which is mainly due to the change of the coordination number of Fe atoms in these ternary Ce–Fe–B amorphous magnets. Though the entropy change is low, the refrigeration capacities are in the ranges of 116–150 J kg −1 and 319–420 J kg −1 , respectively, for the magnetic field changes of 0–2 T and 0–5 T, which is comparable with those of conventional magnetic materials for room-temperature refrigeration. Given the low cost of Fe and Ce, Ce–Fe–B amorphous magnets are attractive magnetic refrigerant candidates. (paper)

  10. Pressure and Temperature of the Room 1 for the Pipe Break Accidents of the 3-Pin Fuel Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Park, S. K.; Chi, D. Y.; Sim, B. S.; Park, K. N.; Ahn, S. H.; Lee, J. M.; Lee, C. Y.; Kim, H. R

    2005-08-15

    This report deals with the prediction of the pressure and temperature of the room 1 for the pipe break accidents of the 3-pin fuel test loop. The 3-pin fuel test loop is an experimental facility for nuclear fuel tests at the operation conditions similar to those of PWR and CANDU power plants. Because the most processing systems of the 3-pin fuel test loop are placed in the room 1. The structural integrity of the room 1 should be evaluated for the postulated accident conditions. Therefore the pressures and temperatures of the room 1 needed for the structural integrity evaluation have been calculated by using MARS code. The pressures and temperatures of the room 1 have been calculated in various conditions such as the thermal hydraulic operation parameters, the locations of pipe break, and the thermal properties of the room 1 wall. It is assumed that the pipe break accident occurs in the letdown operation without regeneration, because the mass and energy release to the room 1 is expected to be the largest. As a result of the calculations the maximum pressure and temperature are predicted to be 208kPa and 369.2K(96.0 .deg. C) in case the heat transfer is considered in the room 1 wall. However the pressure and temperature are asymptotically 243kPa and 378.1K(104.9 .deg. C) assuming that the heat transfer does not occur in the room 1 wall.

  11. Compressive and flexural strength of expanded perlite aggregate mortar subjected to high temperatures

    Science.gov (United States)

    Zulkifeli, Muhamad Faqrul Hisham bin Mohd; Saman@Hj Mohamed, Hamidah binti Mohd

    2017-08-01

    Work on thermal resistant of outer structures of buildings is one of the solution to reduce death, damages and properties loss in fire cases. Structures protected with thermal resistant materials can delay or avoid failure and collapse during fire. Hence, establishment of skin cladding with advance materials to protect the structure of buildings is a necessary action. Expanded perlite is a good insulation material which can be used as aggregate replacement in mortar. This study is to study on mortar mechanical properties of flexural and compressive strength subjected to elevated temperatures using expanded perlite aggregate (EPA). This study involved experimental work which was developing mortar with sand replacement by volume of 0%, 10%, 20%, 30% and 40% of EPA and cured for 56 days. The mortars then exposed to 200°C, 400 °C, 700 °C and 1000 °C. Flexural and compressive strength of the mortar were tested. The tests showed that there were increased of flexural and compressive strength at 200°C, and constantly decreased when subjected to 400°C, 700°C and 1000 °C. There were also variation of strengths at different percentages of EPA replacement. Highest compressive strength and flexural strength recorded were both at 200 °C with 65.52 MPa and 21.34 MPa respectively. The study conclude that by using EPA as aggregate replacement was ineffective below elevated temperatures but increased the performance of the mortar at elevated temperatures.

  12. 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

  13. 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...

  14. 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.

  15. 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.

  16. On the room temperature multiferroic BiFeO3: magnetic, dielectric and thermal properties

    Science.gov (United States)

    Lu, J.; Günther, A.; Schrettle, F.; Mayr, F.; Krohns, S.; Lunkenheimer, P.; Pimenov, A.; Travkin, V. D.; Mukhin, A. A.; Loidl, A.

    2010-06-01

    Magnetic dc susceptibility between 1.5 and 800 K, ac susceptibility and magnetization, thermodynamic properties, temperature dependence of radio and audio-wave dielectric constants and conductivity, contact-free dielectric constants at mm-wavelengths, as well as ferroelectric polarization are reported for single crystalline BiFeO3. A well developed anomaly in the magnetic susceptibility signals the onset of antiferromagnetic order close to 635 K. Beside this anomaly no further indications of phase or glass transitions are indicated in the magnetic dc and ac susceptibilities down to the lowest temperatures. The heat capacity has been measured from 2 K up to room temperature and significant contributions from magnon excitations have been detected. From the low-temperature heat capacity an anisotropy gap of the magnon modes of the order of 6 meV has been determined. The dielectric constants measured in standard two-point configuration are dominated by Maxwell-Wagner like effects for temperatures T > 300 K and frequencies below 1 MHz. At lower temperatures the temperature dependence of the dielectric constant and loss reveals no anomalies outside the experimental errors, indicating neither phase transitions nor strong spin phonon coupling. The temperature dependence of the dielectric constant was measured contact free at microwave frequencies. At room temperature the dielectric constant has an intrinsic value of 53. The loss is substantial and strongly frequency dependent indicating the predominance of hopping conductivity. Finally, in small thin samples we were able to measure the ferroelectric polarization between 10 and 200 K. The saturation polarization is of the order of 40 μC/cm2, comparable to reports in literature.

  17. 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.

  18. 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.

  19. 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.

  20. 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.)

  1. 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.

  2. Experimental Study on Compression/Absorption High-Temperature Hybrid Heat Pump with Natural Refrigerant Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Young; Park, Seong Ryong; Baik, Young Jin; Chang, Ki Chang; Ra, Ho Sang; Kim, Min Sung [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Kim, Yong Chan [Korea University, Seoul (Korea, Republic of)

    2011-12-15

    This research concerns the development of a compression/absorption high-temperature hybrid heat pump that uses a natural refrigerant mixture. Heat pumps based on the compression/absorption cycle offer various advantages over conventional heat pumps based on the vapor compression cycle, such as large temperature glide, temperature lift, flexible operating range, and capacity control. In this study, a lab-scale prototype hybrid heat pump was constructed with a two-stage compressor, absorber, desorber, desuperheater, solution heat exchanger, solution pump, liquid/vapor separator, and rectifier as the main components. The hybrid heat pump system operated at 10-kW-class heating capacity producing hot water whose temperature was more than 90 .deg. C when the heat source and sink temperatures were 50 .deg. C. Experiments with various NH{sub 3}/H{sub 2}O mass fractions and compressor/pump circulation ratios were performed on the system. From the study, the system performance was optimized at a specific NH{sub 3} concentration.

  3. Room temperature nanojoining of Cu-Ag core-shell nanoparticles and nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiaqi; Shin, Seungha, E-mail: sshin@utk.edu [The University of Tennessee, Department of Mechanical, Aerospace and Biomedical Engineering (United States)

    2017-02-15

    Room temperature (T{sub room}, 300 K) nanojoining of Ag has been widely employed in fabrication of microelectronic applications where the shapes and structures of microelectronic components must be maintained. In this research, the joining processes of pure Ag nanoparticles (NPs), Cu-Ag core-shell NPs, and nanowires (NWs) are studied using molecular dynamics simulations at T{sub room}. The evolution of densification, potential energy, and structural deformation during joining process are analyzed to identify joining mechanisms. Depending on geometry, different joining mechanisms including crystallization-amorphization, reorientation, Shockley partial dislocation are determined. A three-stage joining scenario is observed in both joining process of NPs and NWs. Besides, the Cu core does not participate in all joining processes, however, it enhances the mobility of Ag shell atoms, contributing to a higher densification and bonding strength at T{sub room}, compared with pure Ag nanomaterials. The tensile test shows that the nanojoint bears higher rupture strength than the core-shell NW itself. This study deepens understanding in the underlying joining mechanisms and thus nanojoint with desirable thermal, electrical, and mechanical properties could be potentially achieved.

  4. Room temperature nanojoining of Cu-Ag core-shell nanoparticles and nanowires

    International Nuclear Information System (INIS)

    Wang, Jiaqi; Shin, Seungha

    2017-01-01

    Room temperature (T room , 300 K) nanojoining of Ag has been widely employed in fabrication of microelectronic applications where the shapes and structures of microelectronic components must be maintained. In this research, the joining processes of pure Ag nanoparticles (NPs), Cu-Ag core-shell NPs, and nanowires (NWs) are studied using molecular dynamics simulations at T room . The evolution of densification, potential energy, and structural deformation during joining process are analyzed to identify joining mechanisms. Depending on geometry, different joining mechanisms including crystallization-amorphization, reorientation, Shockley partial dislocation are determined. A three-stage joining scenario is observed in both joining process of NPs and NWs. Besides, the Cu core does not participate in all joining processes, however, it enhances the mobility of Ag shell atoms, contributing to a higher densification and bonding strength at T room , compared with pure Ag nanomaterials. The tensile test shows that the nanojoint bears higher rupture strength than the core-shell NW itself. This study deepens understanding in the underlying joining mechanisms and thus nanojoint with desirable thermal, electrical, and mechanical properties could be potentially achieved.

  5. 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.

  6. Photon antibunching in single-walled carbon nanotubes at telecommunication wavelengths and room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Takumi, E-mail: endou@az.appi.keio.ac.jp; Ishi-Hayase, Junko; Maki, Hideyuki, E-mail: maki@appi.keio.ac.jp [Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522 (Japan)

    2015-03-16

    We investigated the photoluminescence of individual air-suspended single-walled carbon nanotubes (SWNTs) from 6 to 300 K. Time-resolved and antibunching measurements over the telecommunication wavelength range were performed using a superconducting single-photon detector. We detected moderate temperature independent antibunching behavior over the whole temperature range studied. To investigate the exciton dynamics, which is responsible for the antibunching behavior, we measured excitation-power and temperature dependence of the photoluminescence spectra and lifetime decay curves. These measurements suggested an exciton confinement effect that is likely caused by high-dielectric amorphous carbon surrounding the SWNTs. These results indicate that SWNTs are good candidates for light sources in quantum communication technologies operating in the telecommunication wavelength range and at room temperature.

  7. Synthesis of full-density nanocrystalline tungsten carbide by reduction of tungstic oxide at room temperature

    International Nuclear Information System (INIS)

    El-Eskandarany, M.S.; Omori, M.; Ishikuro, M.; Konno, T.J.; Takada, K.; Sumiyama, K.; Hirai, T.; Suzuki, K.

    1996-01-01

    Among the hard alloys, WC alloys find wide industrial applications as tips for cutting tools and wear-resistant parts. Their intrinsic resistance to oxidation and corrosion at high temperatures also makes them desirable as a protective coating for devices at elevated temperatures. In the industrial scale of production, WC is prepared by a direct union of the elements at a temperature of 3,273 to 3,473 K. Accordingly, the high cost of preparation is a disadvantage of this process. Here, the authors report a novel technique for preparing a large amount of WC powder using a simple method. This process is based on mechanical solid-state reduction (MSSR) followed y solid-state reaction (SSR) during room-temperature ball milling (a high energy ball mill, Fritsch P6, was used at a rotation speed of 4.2 s -1 ) of a mixture of WO 3 , Mg, and C powders

  8. The compressive behaviour and constitutive equation of polyimide foam in wide strain rate and temperature

    Directory of Open Access Journals (Sweden)

    Yoshimoto Akifumi

    2015-01-01

    Full Text Available These days, polymer foams, such as polyurethane foam and polystyrene foam, are used in various situations as a thermal insulator or shock absorber. In general, however, their strength is insufficient in high temperature environments because of their low glass transition temperature. Polyimide is a polymer which has a higher glass transition temperature and high strength. Its mechanical properties do not vary greatly, even in low temperature environments. Therefore, polyimide foam is expected to be used in the aerospace industry. Thus, the constitutive equation of polyimide foam that can be applied across a wide range of strain rates and ambient temperature is very useful. In this study, a series of compression tests at various strain rates, from 10−3 to 103 s−1 were carried out in order to examine the effect of strain rate on the compressive properties of polyimide foam. The flow stress of polyimide foam increased rapidly at dynamic strain rates. The effect of ambient temperature on the properties of polyimide foam was also investigated at temperature from − 190 °C to 270°∘C. The flow stress decreased with increasing temperature.

  9. Efficient room temperature hydrogen sensor based on UV-activated ZnO nano-network

    Science.gov (United States)

    Kumar, Mohit; Kumar, Rahul; Rajamani, Saravanan; Ranwa, Sapana; Fanetti, Mattia; Valant, Matjaz; Kumar, Mahesh

    2017-09-01

    Room temperature hydrogen sensors were fabricated from Au embedded ZnO nano-networks using a 30 mW GaN ultraviolet LED. The Au-decorated ZnO nano-networks were deposited on a SiO2/Si substrate by a chemical vapour deposition process. X-ray diffraction (XRD) spectrum analysis revealed a hexagonal wurtzite structure of ZnO and presence of Au. The ZnO nanoparticles were interconnected, forming nano-network structures. Au nanoparticles were uniformly distributed on ZnO surfaces, as confirmed by FESEM imaging. Interdigitated electrodes (IDEs) were fabricated on the ZnO nano-networks using optical lithography. Sensor performances were measured with and without UV illumination, at room temperate, with concentrations of hydrogen varying from 5 ppm to 1%. The sensor response was found to be ˜21.5% under UV illumination and 0% without UV at room temperature for low hydrogen concentration of 5 ppm. The UV-photoactivated mode enhanced the adsorption of photo-induced O- and O2- ions, and the d-band electron transition from the Au nanoparticles to ZnO—which increased the chemisorbed reaction between hydrogen and oxygen. The sensor response was also measured at 150 °C (without UV illumination) and found to be ˜18% at 5 ppm. Energy efficient low cost hydrogen sensors can be designed and fabricated with the combination of GaN UV LEDs and ZnO nanostructures.

  10. Ambient temperature and emergency room admissions for acute coronary syndrome in Taiwan

    Science.gov (United States)

    Liang, Wen-Miin; Liu, Wen-Pin; Chou, Sze-Yuan; Kuo, Hsien-Wen

    2008-01-01

    Acute coronary syndrome (ACS) is an important public health problem around the world. Since there is a considerable seasonal fluctuation in the incidence of ACS, climatic temperature may have an impact on the onset of this disease. The objective of this study was to assess the relationship between the average daily temperature, diurnal temperature range and emergency room (ER) admissions for ACS in an ER in Taichung City, Taiwan. A longitudinal study was conducted which assessed the correlation of the average daily temperature and the diurnal temperature range to ACS admissions to the ER of the city’s largest hospital. Daily ER admissions for ACS and ambient temperature were collected from 1 January 2000 to 31 March 2003. The Poisson regression model was used in the analysis after adjusting for the effects of holiday, season, and air pollutant concentrations. The results showed that there was a negative significant association between the average daily temperature and ER admissions for ACS. ACS admissions to the ER increased 30% to 70% when the average daily temperature was lower than 26.2°C. A positive association between the diurnal temperature range and ACS admissions was also noted. ACS admissions increased 15% when the diurnal temperature range was over 8.3°C. The data indicate that patients suffering from cardiovascular disease must be made aware of the increased risk posed by lower temperatures and larger changes in temperature. Hospitals and ERs should take into account the increased demand of specific facilities during colder weather and wider temperature variations.

  11. Tension–compression asymmetry in an extruded Mg alloy AM30: Temperature and strain rate effects

    Energy Technology Data Exchange (ETDEWEB)

    Zachariah, Z. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Tatiparti, Sankara Sarma V.; Mishra, S.K.; Ramakrishnan, N. [General Motors Technical Center, ITPL, Whitefield, Bangalore 560066 (India); Ramamurty, U., E-mail: ramu@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2013-06-10

    The effect of strain rate, ε, and temperature, T, on the tension–compression asymmetry (TCA) in a dilute and wrought Mg alloy, AM30, over a temperature range that covers both twin accommodated deformation (below 250 °C in compression) as well as dislocation-mediated plasticity (above 250 °C) has been investigated. For this purpose, uniaxial tension and compression tests were conducted at T ranging from 25 to 400 °C with ε varying between 10{sup −2} and 10 s{sup −1}. In most of the cases, the stress–strain responses in tension and compression are distinctly different; with compression responses ‘concaving upward,’ due to {101-bar 2} tensile twinning at lower plastic strains followed by slip and strain hardening at higher levels of deformation, for T below 250 °C. This results in significant levels of TCA at T<250 °C, reducing substantially at high temperatures. At T=150 and 250 °C, high ε leads to high TCA, in particular at T=250 °C and ε=10 s{sup −1}, suggesting that twin-mediated plastic deformation takes precedence at high rates of loading even at sufficiently high T. TCA becomes negligible at T=350 °C; however at T=400 °C, as ε increases TCA gets higher. Microscopy of the deformed samples, carried out by using electron back-scattered diffraction (EBSD), suggests that at T>250 °C dynamic recrystallization begins between accompanied by reduction in the twinned fraction that contributes to the decrease of the TCA.

  12. A flexible numerical model to study an active magnetic refrigerator for near room temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Aprea, Ciro; Maiorino, Angelo [Department of Mechanical Engineering, University of Salerno, Via Ponte Don Melillo 1, 84084 Fisciano (Salerno) (Italy)

    2010-08-15

    Magnetic refrigeration is an emerging technology based on the magnetocaloric effect in solid-state refrigerants. This technology offers a smaller global environmental impact than the refrigeration obtained by means of the classical vapor compression machines operating with fluids such as HFCs. The Active Magnetic Regenerative Refrigeration (AMRR) is currently the most studied ant tested magnetic cycle. It combines the regenerative properties of a high specific heat solid porous matrix with the ability of performing thermo-magnetic cycles thanks to the magnetocaloric property of the refrigerant; while a fluid pulsing through the regenerator works as a heat transfer medium. An active magnetic regenerator can provide larger temperature spans making up for the local small temperature variation of the refrigerant. In the present paper, a practical model for predicting the performance and efficiency of an AMRR cycle has been developed. The model evaluates both the refrigerant properties and the entire cycle of an AMR operating in conformity with a Brayton regenerative cycle. The magnetocaloric material of choice is gadolinium, while the heat transfer medium is liquid water. With this model can be predicted the refrigeration capacity, the power consumption and consequently the Coefficient of Performance. The results show a greater COP when compared to a classical vapor compression plant working between the same temperature levels. (author)

  13. A flexible numerical model to study an active magnetic refrigerator for near room temperature applications

    International Nuclear Information System (INIS)

    Aprea, Ciro; Maiorino, Angelo

    2010-01-01

    Magnetic refrigeration is an emerging technology based on the magnetocaloric effect in solid-state refrigerants. This technology offers a smaller global environmental impact than the refrigeration obtained by means of the classical vapor compression machines operating with fluids such as HFCs. The Active Magnetic Regenerative Refrigeration (AMRR) is currently the most studied ant tested magnetic cycle. It combines the regenerative properties of a high specific heat solid porous matrix with the ability of performing thermo-magnetic cycles thanks to the magnetocaloric property of the refrigerant; while a fluid pulsing through the regenerator works as a heat transfer medium. An active magnetic regenerator can provide larger temperature spans making up for the local small temperature variation of the refrigerant. In the present paper, a practical model for predicting the performance and efficiency of an AMRR cycle has been developed. The model evaluates both the refrigerant properties and the entire cycle of an AMR operating in conformity with a Brayton regenerative cycle. The magnetocaloric material of choice is gadolinium, while the heat transfer medium is liquid water. With this model can be predicted the refrigeration capacity, the power consumption and consequently the Coefficient of Performance. The results show a greater COP when compared to a classical vapor compression plant working between the same temperature levels.

  14. 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.

  15. Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival.

    Science.gov (United States)

    Chen, Le; Jian, Shanshan; Bi, Jinhua; Li, Yunlong; Chang, Zhizhou; He, Jian; Ye, Xiaomei

    2016-05-01

    Tomato plant waste (TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS (total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic (37±1°C) and room (20-25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416L/kg VS (volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR (polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA (volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety. Copyright © 2015. Published by Elsevier B.V.

  16. Deposition of silicon oxynitride at room temperature by Inductively Coupled Plasma-CVD

    Energy Technology Data Exchange (ETDEWEB)

    Zambom, Luis da Silva [MPCE-Faculdade de Tecnologia de Sao Paulo - CEETEPS, Pca Coronel Fernando Prestes, 30, Sao Paulo - CEP 01124-060 (Brazil)]. E-mail: zambom@lsi.usp.br; Verdonck, Patrick [PSI-LSI-Escola Politecnica da Universidade de Sao Paulo (Brazil)]. E-mail: patrick@lsi.usp.br

    2006-10-25

    Oxynitride thin films are used in important optical applications and as gate dielectric for MOS devices. Their traditional deposition processes have the drawbacks that high temperatures are needed, high mechanical stresses are induced and the deposition rate is low. Plasma assisted processes may alleviate these problems. In this study, oxynitride films were deposited at room temperature through the chemical reaction of silane, nitrogen and nitrous oxide (N{sub 2}O), in a conventional LPCVD furnace, which was modified into a high density Inductively Coupled Plasma (ICP) reactor. Deposition rates increased with applied coil power and were never lower than 10 nm/min, quite high for room temperature depositions. The films' refractive indexes and FTIR spectra indicate that for processes with low N{sub 2}O gas concentrations, when mixed together with N{sub 2} and SiH{sub 4}, nitrogen was incorporated in the film. This incorporation increased the resistivity, which was up to 70 G{omega} cm, increased the refractive index, from approximately 1.47 to approximately 1.50, and decreased the dielectric constant of these films, which varied in the 4-14 range. These characteristics are adequate for electric applications e.g. for TFT fabrication on glass or polymers which can not stand high temperature steps.

  17. La0.7Sr0.3MnO3 Thin Films for Magnetic and Temperature Sensors at Room Temperature

    Directory of Open Access Journals (Sweden)

    Sheng Wu

    2012-03-01

    Full Text Available In this paper, the potentialities of the manganese oxide La0.7Sr0.3MnO3 (LSMO for the realization of sensitive room temperature thermometers and magnetic sensors are discussed. LSMO exhibits both a large change of the resistance versus temperature at its metal-to-insulator transition (about 330 K and low field magnetoresistive effects at room temperature. The sensor performances are described in terms of signal-to-noise ratio in the 1 Hz - 100 kHz frequency range. It is shown that due to the very low 1/f noise level, LSMO based sensors can exhibit competitive performances at room temperature.

  18. 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.

  19. The effect of wall temperature distribution on streaks in compressible turbulent boundary layer

    Science.gov (United States)

    Zhang, Zhao; Tao, Yang; Xiong, Neng; Qian, Fengxue

    2018-05-01

    The thermal boundary condition at wall is very important for the compressible flow due to the coupling of the energy equation, and a lot of research works about it were carried out in past decades. In most of these works, the wall was assumed as adiabatic or uniform isothermal surface; the flow over a thermal wall with some special temperature distribution was seldom studied. Lagha studied the effect of uniform isothermal wall on the streaks, and pointed out that higher the wall temperature is, the longer the streak (POF, 2011, 23, 015106). So, we designed streamwise stripes of wall temperature distribution on the compressible turbulent boundary layer at Mach 3.0 to learn the effect on the streaks by means of direct numerical simulation in this paper. The mean wall temperature is equal to the adiabatic case approximately, and the width of the temperature stripes is in the same order as the width of the streaks. The streak patterns in near-wall region with different temperature stripes are shown in the paper. Moreover, we find that there is a reduction of friction velocity with the wall temperature stripes when compared with the adiabatic case.

  20. Room temperature elastic--plastic response of thin-walled tubes subjected to nonradial combinations of axial and torsional loadings

    International Nuclear Information System (INIS)

    Liu, K.C.

    1975-01-01

    Two tubular specimens of type 304 stainless steel with uniform thin walls were subjected to a program of segmental combined tension/compression and torsion loadings at room temperature. A proportional, or radial, loading into the plastic range was initially applied to each specimen. Two nonproportional (nonradial) loadings along straight line segments for which neither the loading paths nor their linear extrapolations passed through the origin of the stress space were then applied. The axial and torsional stress-strain curves for these segmental prestress loadings were plotted. Hence, the stress-strain response characteristics for nonproportional loadings as well as for proportional loading can be studied. In addition, the axial and torsional plastic strain components were calculated, and the total plastic strain trajectories were plotted in a plastic strain space. Finally, using results from a detailed study of yield surfaces, which was performed for the first specimen, a spectrum of initial and subsequent yield curves corresponding to the segmental prestress loadings is presented. (U.S.)

  1. Deformation bands in ceria-stabilized tetragonal zirconia/alumina. 2: Stress-induced aging at room temperature

    International Nuclear Information System (INIS)

    Sergo, V.; Clarke, D.R.

    1995-01-01

    A stress-induced aging phenomenon is observed to occur at room temperature in deformation bands introduced into a 8.5 mol% ceria-stabilized tetragonal zirconia/alumina (Ce-TZP/Al 2 O 3 ) composite by flexural loading. The aging occurs with time after unloading and in laboratory air. Over a period of 100 days, the concentration of monoclinic zirconia within a deformation band increases and, in addition, the wedge-shaped deformation band grows with time. Accompanying these two changes are an increase in the tensile stress in the remaining tetragonal zirconia within the deformation band and a consequential increase in the overall compressive stress within the band. The average value of the monoclinic concentration within the deformation band is found to increase parabolically with time, suggesting the mechanism responsible for the observed aging is diffusion limited. Away from the deformation bands, no aging is observed to occur, suggesting aging is stress dependent. Although a water-vapor-mediated mechanism cannot be ruled out, it is proposed that the observed aging is in fact due to a tensile stress assisted chemical reduction of Ce 4+ to Ce 3+ whose rate is controlled by the indiffusion of oxygen vacancies driven by the tensile stress gradient. It is further proposed that the deformation band grows with time the region ahead of the band is under tension a subject to an enhanced rate of reduction

  2. Determination of hydrogen diffusivity and permeability in W near room temperature applying a tritium tracer technique

    International Nuclear Information System (INIS)

    Ikeda, T.; Otsuka, T.; Tanabe, T.

    2011-01-01

    Tungsten is a primary candidate of plasma facing material in ITER and beyond, owing to its good thermal property and low erosion. But hydrogen solubility and diffusivity near ITER operation temperatures (below 500 K) have scarcely studied. Mainly because its low hydrogen solubility and diffusivity at lower temperatures make the detection of hydrogen quite difficult. We have tried to observe hydrogen plasma driven permeation (PDP) through nickel and tungsten near room temperatures applying a tritium tracer technique, which is extremely sensible to detect tritium diluted in hydrogen. The apparent diffusion coefficients for PDP were determined by permeation lag times at first time, and those for nickel and tungsten were similar or a few times larger than those for gas driven permeation (GDP). The permeation rates for PDP in nickel and tungsten were larger than those for GDP normalized to the same gas pressure about 20 and 5 times larger, respectively.

  3. Mechanistic insights into the room temperature transitions of polytetrafluoroethylene during electron-beam irradiation

    Science.gov (United States)

    Fu, Congli; Yu, Xianwei; Zhao, Xiaofeng; Wang, Xiuli; Gu, Aiqun; Xie, Meiju; Chen, Chen; Yu, Zili

    2017-11-01

    In order to recognize the characteristic thermal transitions of polytetrafluoroethylene (PTFE) occurring at 19 °C and 30 °C, PTFE is irradiated on electron beam accelerator at room temperature and analyzed by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results suggest that the two transition temperatures decrease considerably with increasing irradiation doses. Based on the results of structural analysis, the decrease of the two transition temperatures is supposed to be highly relevant to the structural changes. In particular, the content and structure of the side groups generated in PTFE are responsible for the variations of the two thermal transitions after irradiation, offering fundamental insights into the reaction mechanisms of PTFE during irradiation.

  4. Quantitative mid-infrared spectra of allene and propyne from room to high temperatures

    KAUST Repository

    Es-sebbar, Et-touhami

    2014-11-01

    Allene (a-C3H4; CH2CCH2) and propyne (p-C3H4; CH3C2H) have attracted much interest because of their relevance to the photochemistry in astrophysical environments as well as in combustion processes. Both allene and propyne have strong absorption in the infrared region. In the present work, infrared spectra of a-C3H4 and p-C3H4 are measured in the gas phase at temperatures ranging from 296 to 510 K. The spectra are measured over the 580-3400 cm-1 spectral region at resolutions of 0.08 and 0.25 cm-1 using Fourier Transform Infrared spectroscopy. Absolute integrated intensities of the main infrared bands are determined at room temperature and compared with values derived from literature for both molecules. Integrated band intensities are also determined as a function of temperature in various spectral regions.

  5. 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.

  6. Quantitative mid-infrared spectra of allene and propyne from room to high temperatures

    KAUST Repository

    Es-sebbar, Et-touhami; Jolly, A.; Benilan, Y.; Farooq, Aamir

    2014-01-01

    Allene (a-C3H4; CH2CCH2) and propyne (p-C3H4; CH3C2H) have attracted much interest because of their relevance to the photochemistry in astrophysical environments as well as in combustion processes. Both allene and propyne have strong absorption in the infrared region. In the present work, infrared spectra of a-C3H4 and p-C3H4 are measured in the gas phase at temperatures ranging from 296 to 510 K. The spectra are measured over the 580-3400 cm-1 spectral region at resolutions of 0.08 and 0.25 cm-1 using Fourier Transform Infrared spectroscopy. Absolute integrated intensities of the main infrared bands are determined at room temperature and compared with values derived from literature for both molecules. Integrated band intensities are also determined as a function of temperature in various spectral regions.

  7. Room temperature giant and linear magnetoresistance in topological insulator Bi2Te3 nanosheets.

    Science.gov (United States)

    Wang, Xiaolin; Du, Yi; Dou, Shixue; Zhang, Chao

    2012-06-29

    Topological insulators, a new class of condensed matter having bulk insulating states and gapless metallic surface states, have demonstrated fascinating quantum effects. However, the potential practical applications of the topological insulators are still under exploration worldwide. We demonstrate that nanosheets of a Bi(2)Te(3) topological insulator several quintuple layers thick display giant and linear magnetoresistance. The giant and linear magnetoresistance achieved is as high as over 600% at room temperature, with a trend towards further increase at higher temperatures, as well as being weakly temperature-dependent and linear with the field, without any sign of saturation at measured fields up to 13 T. Furthermore, we observed a magnetic field induced gap below 10 K. The observation of giant and linear magnetoresistance paves the way for 3D topological insulators to be useful for practical applications in magnetoelectronic sensors such as disk reading heads, mechatronics, and other multifunctional electromagnetic applications.

  8. Numerical modelling and analysis of a room temperature magnetic refrigeration system

    DEFF Research Database (Denmark)

    Petersen, Thomas Frank

    This thesis presents a two-dimensional mathematical model of an Active Magnetic Regenerator (AMR) system which is used for magnetic refrigeration at room temperature. The purpose of the model is to simulate a laboratory-scale AMR constructed at Risø National Laboratory. The AMR model geometry....... The AMR performs a cyclic process, and to simulate the AMR refrigeration cycle the model starts from an initial temperature distribution in the regenerator and fluid channel and takes time steps forward in time until the cyclical steady-state is obtained. The model can therefore be used to study both...... transient and steady-state phenomena. The AMR performance can be evaluated in terms of the no-load temperature span as well as the refrigeration capacity and the COP. The AMR model was verified extensively and it was concluded that the model has energy conservation and that the solution is independent...

  9. Overnight storage of whole blood: cooling and transporting blood at room temperature under extreme temperature conditions.

    Science.gov (United States)

    Thibault, L; Beauséjour, A; Jacques, A; Ducas, E; Tremblay, M

    2014-02-01

    Many countries allow the overnight storage of whole blood (WB) at ambient temperature. Some countries, such as Canada, also require a rapid cooling of WB with an active cooling system. Given the significant operational constraints associated with current cooling systems, an alternative method for cooling and transporting WB at 20-24°C was evaluated. Phase 22 cooling packs (TCP Reliable Inc., USA) were used in combination with vacuum-insulated panel (VIP) boxes. Temperature profiles of simulated WB units were studied in extreme temperatures (-35 and 40°C). The quality of blood components prepared using Phase 22 packs and CompoCool-WB (Fresenius HemoCare, Germany) was studied. Phase 22 packs reduced the temperature of simulated WB bags from 37 to 24°C in 1·7 ± 0·2 h. Used in combination with VIP boxes, Phase 22 packs maintain the temperature of bags between 20 and 24°C for 15 and 24 h, compared to 2 and 11 h with CompoCool-WB, when exposed at -35 and 40°C, respectively. The quality of platelet concentrates and plasma was comparable, regardless of the cooling system used. For red blood cell units, per cent haemolysis on day 42 was slightly higher in products prepared after cooling with Phase 22 packs compared to CompoCool-WB (0·33 ± 0·15% vs. 0·21 ± 0·06%; P environmental conditions. © 2013 International Society of Blood Transfusion.

  10. Room temperature performance of mid-wavelength infrared InAsSb nBn detectors

    Energy Technology Data Exchange (ETDEWEB)

    Soibel, Alexander; Hill, Cory J.; Keo, Sam A.; Hoglund, Linda; Rosenberg, Robert; Kowalczyk, Robert; Khoshakhlagh, Arezou; Fisher, Anita; Ting, David Z.-Y.; Gunapala, Sarath D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, California 91030 (United States)

    2014-07-14

    In this work, we investigate the high temperature performance of mid-wavelength infrared InAsSb-AlAsSb nBn detectors with cut-off wavelengths near 4.5 μm. The quantum efficiency of these devices is 35% without antireflection coatings and does not change with temperature in the 77–325 K temperature range, indicating potential for room temperature operation. The current generation of nBn detectors shows an increase of operational bias with temperature, which is attributed to a shift in the Fermi energy level in the absorber. Analysis of the device performance shows that operational bias and quantum efficiency of these detectors can be further improved. The device dark current stays diffusion limited in the 150 K–325 K temperature range and becomes dominated by generation-recombination processes at lower temperatures. Detector detectivities are D*(λ) = 1 × 10{sup 9} (cm Hz{sup 0.5}/W) at T = 300 K and D*(λ) = 5 × 10{sup 9} (cm Hz{sup 0.5}/W) at T = 250 K, which is easily achievable with a one stage TE cooler.

  11. Compressive behavior of steel fiber reinforced recycled aggregate concrete after exposure to elevated temperatures

    OpenAIRE

    Chen, G. M.; He, Y. H.; Yang, H.; Chen, J. F.; Guo, Y.C.

    2014-01-01

    For sustainability considerations, the use of recycled aggregate in concrete has attracted many interests in the research community. One of the main concerns for using such concrete in buildings is its spalling in fire. This may be alleviated by adding steel fibers to form steel fiber reinforced recycled aggregate concrete (SFRAC). This paper presents an experimental investigation into the compressive properties of SFRAC cylinders after exposure to elevated temperatures, including the compres...

  12. Mechanical Properties of Discontinuous Precipitated Al-Zn Alloys after Drawing at Room and Cryogenic Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Soo; Lee, Jehyun [Changwon National University, Changwon (Korea, Republic of); Han, Seung Zeon; Ahn, Jee Hyuk [Korea Institute of Materials Science, Changwon (Korea, Republic of); Lim, Sung Hwan [Kangwon National University, Chuncheon (Korea, Republic of); Kim, Kwang Ho [Pusan National University, Pusan (Korea, Republic of); Kim, Sang sik [Gyeongsang National University, Jinju (Korea, Republic of)

    2017-02-15

    In order to study the effect of microstructural change on the tensile properties of discontinuous precipitated Al-Zn binary alloy, four different Al-Zn alloys(25, 30, 35, 45 wt%Zn) were aged at 160 ℃ for different aging times(0, 5, 15, 30, 60, 120, 360 min) after being solution treated at 400 ℃, and successively drawn at room and cryogenic temperatures(-197 ℃). Discontinuous precipitation was formed during aging in the Al matrix(which contained more than 30 wt%Zn) in Al alloys containing more than 30 wt%Zn. The tensile strength of continuous precipitated Al-35Zn alloy decreased with increasing drawing ratio, however, the tensile strength of discontinuous precipitated Al-35Zn alloy increased with further drawing. The strength and ductility combination, 350 MPa-36%was achieved by drawning discontinuous precipitated Al-Zn alloy at room temperature. The discontinuous precipitated Al-Zn alloy drawn at cryogenic temperature showed a higher value of tensile strength, over 500 MPa, although ductility decreased.

  13. 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)

  14. 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.

  15. Room air temperature affects occupants' physiology, perceptions and mental alertness

    Energy Technology Data Exchange (ETDEWEB)

    Tham, Kwok Wai; Willem, Henry Cahyadi [Department of Building, School of Design and Environment, National University of Singapore, 4 Architecture Drive, Singapore 117566 (Singapore)

    2010-01-15

    Thermal environment that causes thermal discomfort may affect office work performance. However, the mechanisms through which occupants are affected are not well understood. This study explores the plausible mechanism linking room air temperature and mental alertness through perceptual and physiological responses in the tropics. Ninety-six young adults participated as voluntary subjects in a series of experiment conducted in the simulated office settings. Three room air temperatures, i.e. 20.0, 23.0 and 26.0 C were selected as the experimental conditions. Both thermal comfort and thermal sensation changed significantly with time under all exposures (P < 0.0001). Longer exposure at 20.0 C led to cooling sensations due to lower skin temperatures (P < 0.0001) and was perceived as the least comfortable. Nevertheless, this moderate cold exposure induced nervous system activation as demonstrated by the increase of {alpha}-Amylase level (P < 0.0001) and the Tsai-partington test (P < 0.0001). A mechanism linking thermal environment, occupants' responses and performance is proposed. (author)

  16. 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.

  17. Mechanical Properties of Discontinuous Precipitated Al-Zn Alloys after Drawing at Room and Cryogenic Temperatures

    International Nuclear Information System (INIS)

    Kim, Min Soo; Lee, Jehyun; Han, Seung Zeon; Ahn, Jee Hyuk; Lim, Sung Hwan; Kim, Kwang Ho; Kim, Sang sik

    2017-01-01

    In order to study the effect of microstructural change on the tensile properties of discontinuous precipitated Al-Zn binary alloy, four different Al-Zn alloys(25, 30, 35, 45 wt%Zn) were aged at 160 ℃ for different aging times(0, 5, 15, 30, 60, 120, 360 min) after being solution treated at 400 ℃, and successively drawn at room and cryogenic temperatures(-197 ℃). Discontinuous precipitation was formed during aging in the Al matrix(which contained more than 30 wt%Zn) in Al alloys containing more than 30 wt%Zn. The tensile strength of continuous precipitated Al-35Zn alloy decreased with increasing drawing ratio, however, the tensile strength of discontinuous precipitated Al-35Zn alloy increased with further drawing. The strength and ductility combination, 350 MPa-36%was achieved by drawning discontinuous precipitated Al-Zn alloy at room temperature. The discontinuous precipitated Al-Zn alloy drawn at cryogenic temperature showed a higher value of tensile strength, over 500 MPa, although ductility decreased.

  18. 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.

  19. 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 )

  20. 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.

  1. 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.

  2. Stabilized sulfur as cathodes for room temperature sodium-ion batteries.

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yunhua [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Liu, Yang [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies; Zhu, Yujie [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Zheng, Shiyou [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Liu, Yihang [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Luo, Chao [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering; Gaskell, Karen [Univ. of Maryland, College Park, MD (United States). Dept. of Chemistry and Biochemistry; Eichhorn, Bryan [Univ. of Maryland, College Park, MD (United States). Dept. of Chemistry and Biochemistry; Wang, Chunsheng [Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering

    2013-05-01

    Sodium-sulfur batteries, offering high capacity and low cost, are promising alternative to lithium-ion batteries for large-scale energy storage applications. The conventional sodium-sulfur batteries, operating at a high temperature of 300–350°C in a molten state, could lead to severe safety problems. However, the room temperature sodium-sulfur batteries using common organic liuid electrolytes still face a significant challenge due to the dissolution of intermediate sodium polysulfides. For this study, we developed room temperatue sodium-sulfur batteries using a unique porous carbon/sulfur (C/S) composite cathode, which was synthesized by infusing sulfur vapor into porous carbon sphere particles at a high temperatrure of 600°C. The porous C/S composites delivered a reversible capacity of ~860 mAh/g and retained 83% after 300 cycles. The Coulombic efficiency of as high as 97% was observed over 300 cycles. The superior electrochemical performance is attrbuted to the super sulfur stability as evidenced by its lower sensitivity to probe beam irradiation in TEM, XPS and Raman charaterization and high evaperation temperature in TGA. The results make it promising for large-scale grid energy storage and electric vehicles.

  3. All-Electrical Spin Field Effect Transistor in van der Waals Heterostructures at Room Temperature

    Science.gov (United States)

    Dankert, André; Dash, Saroj

    Spintronics aims to exploit the spin degree of freedom in solid state devices for data storage and information processing. Its fundamental concepts (creation, manipulation and detection of spin polarization) have been demonstrated in semiconductors and spin transistor structures using electrical and optical methods. However, an unsolved challenge is the realization of all-electrical methods to control the spin polarization in a transistor manner at ambient temperatures. Here we combine graphene and molybdenum disulfide (MoS2) in a van der Waals heterostructure to realize a spin field-effect transistor (spin-FET) at room temperature. These two-dimensional crystals offer a unique platform due to their contrasting properties, such as weak spin-orbit coupling (SOC) in graphene and strong SOC in MoS2. The gate-tuning of the Schottky barrier at the MoS2/graphene interface and MoS2 channel yields spins to interact with high SOC material and allows us to control the spin polarization and lifetime. This all-electrical spin-FET at room temperature is a substantial step in the field of spintronics and opens a new platform for testing a plethora of exotic physical phenomena, which can be key building blocks in future device architectures.

  4. Transient Temperature Distribution in a Reactor Core with Cylindrical Fuel Rods and Compressible Coolant

    Energy Technology Data Exchange (ETDEWEB)

    Vollmer, H

    1968-04-15

    Applying linearization and Laplace transformation the transient temperature distribution and weighted temperatures in fuel, canning and coolant are calculated analytically in two-dimensional cylindrical geometry for constant material properties in fuel and canning. The model to be presented includes previous models as special cases and has the following novel features: compressibility of the coolant is accounted for. The material properties of the coolant are variable. All quantities determining the temperature field are taken into account. It is shown that the solution for fuel and canning temperature may be given by the aid of 4 basic transfer functions depending on only two variables. These functions are calculated for all relevant rod geometries and material constants. The integrals involved in transfer functions determining coolant temperatures are solved for the most part generally by application of coordinate and Laplace transformation. The model was originally developed for use in steam cooled fast reactor analysis where the coolant temperature rise and compressibility are considerable. It may be applied to other fast or thermal systems after suitable simplifications.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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

  20. 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...

  1. 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)

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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...

  7. 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.

  8. 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

  9. 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.

  10. 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%.

  11. 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

  12. 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 ...

  13. 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%.

  14. 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.

  15. 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.

  16. 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...

  17. 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...

  18. 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

  19. 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.

  20. 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.

  1. 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...

  2. 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...

  3. High Temperature Uniaxial Compression and Stress-Relaxation Behavior of India-Specific RAFM Steel

    Science.gov (United States)

    Shah, Naimish S.; Sunil, Saurav; Sarkar, Apu

    2018-05-01

    India-specific reduced activity ferritic martensitic steel (INRAFM), a modified 9Cr-1Mo grade, has been developed by India as its own structural material for fabrication of the Indian Test Blanket Module (TBM) to be installed in the International Thermonuclear Energy Reactor (ITER). The extensive study on mechanical and physical properties of this material has been currently going on for appraisal of this material before being put to use in the ITER. High temperature compression, stress-relaxation, and strain-rate change behavior of the INRAFM steel have been investigated. The optical microscopic and scanning electron microscopic characterizations were carried out to observe the microstructural changes that occur during uniaxial compressive deformation test. Comparable true plastic stress values at 300 °C and 500 °C and a high drop in true plastic stress at 600 °C were observed during the compression test. Stress-relaxation behaviors were investigated at 500 °C, 550 °C, and 600 °C at a strain rate of 10-3 s-1. The creep properties of the steel at different temperatures were predicted from the stress-relaxation test. The Norton's stress exponent (n) was found to decrease with the increasing temperature. Using Bird-Mukherjee-Dorn relationship, the temperature-compensated normalized strain rate vs stress was plotted. The stress exponent (n) value of 10.05 was obtained from the normalized plot. The increasing nature of the strain rate sensitivity (m) with the test temperature was found from strain-rate change test. The low plastic stability with m 0.06 was observed at 600 °C. The activation volume (V *) values were obtained in the range of 100 to 300 b3. By comparing the experimental values with the literature, the rate-controlling mechanisms at the thermally activated region of high temperature were found to be the nonconservative movement of jogged screw dislocations and thermal breaking of attractive junctions.

  4. 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

  5. Demand control on room level of the supply air temperature in an air heating and ventilation system

    DEFF Research Database (Denmark)

    Polak, Joanna; Afshari, Alireza; Bergsøe, Niels Christian

    2017-01-01

    air heating and ventilation system in a high performance single family house using BSim simulation software. The provision of the desired thermal conditions in different rooms was examined. Results show that the new control strategy can facilitate maintaining of desired temperatures in various rooms......The aim of this study was to investigate a new strategy for control of supply air temperature in an integrated air heating and ventilation system. The new strategy enables demand control of supply air temperature in individual rooms. The study is based on detailed dynamic simulations of a combined....... Moreover, this control strategy enables controlled temperature differentiation between rooms within the house and therefore provides flexibility and better balance in heat delivery. Consequently, the thermal conditions in the building can be improved....

  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. Influence of microstructure on the room temperature flow behaviour of Mod. 9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Kishore, R.; Singh, R.N.; Kashyap, B.P.

    2005-01-01

    The normalizing heat treatment conditions of T-91 grade steel were altered in order to get different austenite/martensite packet grain sizes. Tempering of the steel was carried out at (1) peak hardening temperature and (2) at temperature closer to commercial treatment. Tempering of these specimens, austenitized at a chosen temperature, at the two tempering temperatures resulted in the modification of the fine scale structure by the formation of different carbide types and their distribution. Tensile testing of these specimens (under all the three conditions) was conducted at ambient temperature in order to study the influence of the microstructures on the deformation behaviour. The flow stress, hardness and room temperature impact toughness showed an inverse relation with the martensite packet/austenite grain size. The deformation behavior of the specimens under the three heat treatment conditions was analyzed according to Ashby's model was made assuming. The slip length, λ g , was estimated from the σ-ε 1/2 plot and compared with the relevant microstructure parameters. The as-received material was seen to undergo aligatoring damage during cold rolling and a modification in their microstructure could render a defect free product. (author)

  8. Integrated LTCC pressure/flow/temperature multisensor for compressed air diagnostics.

    Science.gov (United States)

    Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

    2010-01-01

    We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

  9. Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

    Science.gov (United States)

    Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

    2010-01-01

    We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues. PMID:22163518

  10. Tamper temperature and compression from simultaneous proton and alpha-particle measurements in laser fusion experiments

    International Nuclear Information System (INIS)

    Cover, R.A.; Kubis, J.J.; Mayer, F.J.; Slater, D.C.

    1978-01-01

    The energy loss per unit path length for a charged particle incident on a spatially uniform isothermal Maxwellian plasma is a function of the temperature and density of the medium. Within this model the temperature and compression rhoΔr of the tamper of a laser-driven microshell target can be accurately determined, in the absence of electrostatic acceleration, by the simultaneous measurement of the energy loss from 3.52-MeV α particles from D-T reactions and 3.02-MeV protons from D-D reactions

  11. Use of Single-Tow Ceramic Matrix Minicomposites to Determine Fundamental Room and Elevated Temperature Properties

    Science.gov (United States)

    Almansour, Amjad S.

    The room and high temperature mechanical properties of continuous ceramic fiber reinforced matrix composites makes them attractive for implementation in aerospace and nuclear applications. However, the effect of fiber content has not been addressed in previous work. Therefore, single tow composites with fiber content ranging from 3 to 47 % was studied. Single fiber tow minicomposite is the basic architectural feature of woven and laminate ceramic matrix composites (CMCs). An in depth understanding of the initiation and evolution of damage in various ceramic fiber reinforced minicomposites with different fiber volume fractions and interphases was investigated employing several non-destructive evaluation techniques. A new technique is used to determine matrix crack content based on a damage parameter derived from speed of sound measurements which is compared with the established method using cumulative energy of Acoustic Emission (AE) events. Also, a modified theoretical model was implemented to obtain matrix stress at the onset of matrix cracking. Room temperature tensile, high temperature creep rupture and high temperature oxidation degradation loading conditions were all considered and composites' constituents were characterized. Moreover, fibers/matrix load sharing was modeled in creep and fiber volume fraction effect on load transfer was investigated using derived theoretical models. Fibers and matrix creep parameters, load transfer model results and numerical model methodology were used to construct minicomposites' creep strain model to predict creep damage of the different fiber type and content minicomposites. Furthermore, different fiber volume fractions ceramic matrix minicomposites' electrical resistivity temperature dependence isn't well understood. Therefore, the influence of fiber content, heat treatment cycles and creep on electrical resistivity measurements of SiC/SiC minicomposites were also studied here. Next, minicomposites' testing and

  12. Fabrication of a microfluidic chip by UV bonding at room temperature for integration of temperature-sensitive layers

    Science.gov (United States)

    Schlautmann, S.; Besselink, G. A. J.; Radhakrishna Prabhu, G.; Schasfoort, R. B. M.

    2003-07-01

    A method for the bonding of a microfluidic device at room temperature is presented. The wafer with the fluidic structures was bonded to a sensor wafer with gold pads by means of adhesive bonding, utilizing an UV-curable glue layer. To avoid filling the fluidic channels with the glue, a stamping process was developed which allows the selective application of a thin glue layer. In this way a microfluidic glass chip was fabricated that could be used for performing surface plasmon resonance measurements without signs of leakage. The advantage of this method is the possibility of integration of organic layers as well as other temperature-sensitive layers into a microfluidic glass device.

  13. Predicting the Room Air Temperature of the Containment Spray Pump Room for the Loss of HVAC Accidents

    International Nuclear Information System (INIS)

    Yoon, Churl; Park, Jin Hee; Lim, Ho Gon; Han, Sang Hoon

    2007-01-01

    In PSA Models, the HVAC system is essential for the various vital mitigation safety systems operating during a mission time. So far, the unavailability of the safety system when the HVAC system is unavailable, has been applied conservatively or optimistically based on operating experience and expert judgment, so the total core damage frequency could be unrealistic. In this paper, we performed a heat up calculation for the Containment Spray Pump Room at Kori 3 and 4 Units using a CFD code to estimate the operability of the CS pump and its support systems in the pump room under the situation of a loss of the HVAC. The result of this calculation could be applied the PSA Model for Risk Informed Regulation for Kori Units 3 and 4

  14. BF3.SiO2: an efficient catalyst for the synthesis of azo dyes at room temperature

    Directory of Open Access Journals (Sweden)

    Bi Bi Fatemeh Mirjalili

    2012-07-01

    Full Text Available A rapid one-pot method has been developed for the synthesis of azo dyes via ‎sequential diazotization–diazo coupling of aromatic amines with coupling agents at roomtemperature in the presence of BF3.SiO2 as acidic catalyst. The obtained aryl diazonium salts bearing silica supported boron tri-flouride counter ion‎ was sufficiently stable to be kept at roomtemperature in the dry state.‎

  15. 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....

  16. Air temperature determination inside residual heat removal pump room of Angra-1 nuclear power plant after a design basic accident

    International Nuclear Information System (INIS)

    Siniscalchi, Marcio Rezende

    2005-01-01

    This work develops heat transfer theoretical models for determination of air temperature inside the Residual Heat Removal Pump Room of Angra 1 Nuclear Power Plant after a Design Basis Accident without forced ventilation. Two models had been developed. The differential equations are solved by analytical methods. A software in FORTRAN language are developed for simulations of temperature inside rooms for different geometries and materials. (author)

  17. 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...

  18. 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

  19. Experimental Investigation of a Mechanical Vapour Compression Chiller at Elevated Chilled Water Temperatures

    KAUST Repository

    Thu, Kyaw

    2017-05-18

    The performance of a Mechanical Vapour Compression (MVC) chiller is experimentally investigated under operating conditions suitable for sensible cooling. With the emergence of the energy efficient dehumidification systems, it is possible to decouple the latent load from the MVC chillers which can be operated at higher chilled water temperature for handling sensible cooling load. In this article, the performance of the chiller is evaluated at the elevated chilled water outlet temperatures (7 – 17° C) at various coolant temperatures (28 – 32° C) and flow rates (ΔT = 4 and 5° C) for both full- and part-load conditions. Keeping the performance at the AHRI standard as the baseline condition, the efficacy of the chiller in terms of compression ratio, cooling capacity and COP at aforementioned conditions is quantified experimentally. It is observed that for each one-degree Celsius increase in the chilled water temperature, the COP of the chiller improves by about 3.5% whilst the cooling capacity improvement is about 4%. For operation at 17° C chilled water outlet temperature, the improvements in COP and cooling capacity are between 37 – 40% and 40 – 45%, respectively, compared to the performance at the AHRI standards. The performance of the MVC chiller at the abovementioned operation conditions is mapped on the chiller performance characteristic chart.

  20. Experimental Investigation of a Mechanical Vapour Compression Chiller at Elevated Chilled Water Temperatures

    KAUST Repository

    Thu, Kyaw; Saththasivam, Jayaprakash; Saha, Bidyut Baran; Chua, Kian Jon; Srinivasa Murthy, S.; Ng, Kim Choon

    2017-01-01

    The performance of a Mechanical Vapour Compression (MVC) chiller is experimentally investigated under operating conditions suitable for sensible cooling. With the emergence of the energy efficient dehumidification systems, it is possible to decouple the latent load from the MVC chillers which can be operated at higher chilled water temperature for handling sensible cooling load. In this article, the performance of the chiller is evaluated at the elevated chilled water outlet temperatures (7 – 17° C) at various coolant temperatures (28 – 32° C) and flow rates (ΔT = 4 and 5° C) for both full- and part-load conditions. Keeping the performance at the AHRI standard as the baseline condition, the efficacy of the chiller in terms of compression ratio, cooling capacity and COP at aforementioned conditions is quantified experimentally. It is observed that for each one-degree Celsius increase in the chilled water temperature, the COP of the chiller improves by about 3.5% whilst the cooling capacity improvement is about 4%. For operation at 17° C chilled water outlet temperature, the improvements in COP and cooling capacity are between 37 – 40% and 40 – 45%, respectively, compared to the performance at the AHRI standards. The performance of the MVC chiller at the abovementioned operation conditions is mapped on the chiller performance characteristic chart.