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Sample records for charge injection mechanism

  1. Localization and delocalization of charges injected in DNA

    OpenAIRE

    Heim, Thomas; Melin, Thierry; Deresmes, Dominique; Vuillaume, Dominique

    2004-01-01

    To be published in Appl. Phys. Lett. The electrical properties of DNA molecules are investigated by charge injection and electric force microscopy experiments. Prior to injection, DNA molecules exhibit a weak positively charged state. We probe the electrical behaviour of DNA by measuring the localized or delocalized character of the DNA charge states upon injection of excess charges. We show that injected charges do not delocalize for overstretched DNA prepared by a receding meniscus techn...

  2. Charging mechanisms in persistent phosphors

    OpenAIRE

    Smet, Philippe; Van den Eeckhout, Koen; Korthout, Katleen; Botterman, Jonas; van der Kolk, Erik; Bos, Adrie; Dorenbos, Pieter; Poelman, Dirk

    2011-01-01

    The development of novel persistent phosphors is currently hampered by a limited understanding of the charging mechanism. Using x-ray absorption and thermoluminescence spectroscopy we evaluate the validity of recently proposed models for the charging mechanism.

  3. Charge Injection, Charge Trapping and Charge Transfer in Quantum-Dot Solids

    OpenAIRE

    Boehme, S.C.

    2015-01-01

    This study reports on fundamental processes in Quantum-Dot Solids, after light absorption. Transient Absorption and Time-resolved Photoluminescence spectrocopy reveal the dynamics of charge transfer and charge trapping processes. Typically, both occur on a picosecond time scale and compete with each other. We find that the efficiency of these processes depends on the Fermi level in the Quantum-Dot Solid. The latter can be controlled electrochemically, via charge injection into the Quantum-Dot...

  4. Fundamental Investigation of Charge Injection Type of Electrostatic Oil Filter

    Science.gov (United States)

    Tran, Khanh Duong; Yanada, Hideki

    This paper deals with the effects of mechanical factors on the filtration speed of a charge injection type of electrostatic oil filter. The new filter has been proposed by Yanada and his coworkers and it has been demonstrated that the filtration speed can be increased to a great or some degree by injecting charges into oils, but the experimental condition was limited. In this paper, the effects of the number of the projections, the electrode spacing, the applied voltage and the oil temperature on the filtration speed are examined using a simple filter model and various types of oil. In order to discuss the effects of those mechanical factors on the filtration speed, numerical simulation of electrostatic field between electrodes is done and the oil flow caused between the electrodes due to ion drag phenomenon, called the ion drag flow in the paper, is observed using a charge coupled devise (CCD) camera and is analyzed using a particle image velocimetry (PIV) technique. The experiments and numerical simulation make clear the effects of the mechanical factors on the filtration speed. An optimal electrode configuration and operating condition are found out.

  5. Toward charging free plasma etching; Insitu measurement of negative charge injection and charge reduction in a contact hole

    Science.gov (United States)

    Ohmori, Takeshi; Makabe, Toshiaki

    2003-10-01

    It will be essential to develop in-situ diagnostics for damage free plasma etching in the interface under close and complementary cooperation between optical and electric procedure in a top-down nanoscale etching. In our previous paper[1], we have applied an emission selected omputerized tomography close to the wafer exposed to plasma etching, in order to investigate the polarity and the phase of high energy charged particles incident on the wafer, biased deeply by a low frequency source in RIE. A reduction in charging voltage on a contact hole bottom of SiO2 was validated in the pulsed plasma power source in the 2f-CCP in CF_4/Ar, by using a dual measurement system onsisting of a temporal emission CT and a contact hole charging voltage. In the present work, detailed correlational results of the reduction in the charging voltage are shown as a function of phase and amplitude of the single bias pulse at 500 kHz. Discussion is focused both on the injection mechanism of energetic negative charges to the wafer and on the magnitude of the negative charges. As a result, during the off-period 10 us of VHF power source in the dual pulsed 2f-CCP, it is confirmed that; 1)the magnitude of the injected negative charge increases with increasing the on-time of the single bias pulse, and a strong reduction in the charging voltage is performed, 2)a strong negative self-bias-voltage is always kept to have an efficient RIE under energetic positive ion impact on the wafer except for the period of the single bias pulse. Some of predictive story will be also introduced by VicAddress. 1)T.Ohmori, T.K.Goto, T.Kitajima, and T.Makabe, Proc.of Dry Process Symposium 165(2002)Tokyo, and Appl.Phys.Lett.(submitted).

  6. Charge injection in thin dielectric layers by atomic force microscopy: influence of geometry and material work function of the AFM tip on the injection process

    Science.gov (United States)

    Villeneuve-Faure, C.; Makasheva, K.; Boudou, L.; Teyssedre, G.

    2016-06-01

    Charge injection and retention in thin dielectric layers remain critical issues for the reliability of many electronic devices because of their association with a large number of failure mechanisms. To overcome this drawback, a deep understanding of the mechanisms leading to charge injection close to the injection area is needed. Even though the charge injection is extensively studied and reported in the literature to characterize the charge storage capability of dielectric materials, questions about charge injection mechanisms when using atomic force microscopy (AFM) remain open. In this paper, a thorough study of charge injection by using AFM in thin plasma-processed amorphous silicon oxynitride layers with properties close to that of thermal silica layers is presented. The study considers the impact of applied voltage polarity, work function of the AFM tip coating and tip curvature radius. A simple theoretical model was developed and used to analyze the obtained experimental results. The electric field distribution is computed as a function of tip geometry. The obtained experimental results highlight that after injection in the dielectric layer the charge lateral spreading is mainly controlled by the radial electric field component independently of the carrier polarity. The injected charge density is influenced by the nature of electrode metal coating (work function) and its geometry (tip curvature radius). The electron injection is mainly ruled by the Schottky injection barrier through the field electron emission mechanism enhanced by thermionic electron emission. The hole injection mechanism seems to differ from the electron one depending on the work function of the metal coating. Based on the performed analysis, it is suggested that for hole injection by AFM, pinning of the metal Fermi level with the metal-induced gap states in the studied silicon oxynitride layers starts playing a role in the injection mechanisms.

  7. Extracting electrode space charge limited current: Charge injection into conjugated polyelectrolytes with a semiconductor electrode

    Science.gov (United States)

    Walker, Ethan M.; Lonergan, Mark C.

    2016-05-01

    Conjugated polyelectrolytes and related mixed ionic-electronic conductors (MIECs) are being explored for energy applications including solid-state lighting and photovoltaics. Fundamental models of charge injection into MIECs have been primarily developed for MIECs contacted with highly conductive or metal electrodes (MEs), despite many potential applications involving semiconductors. We theoretically and experimentally demonstrate that an appropriate semiconductor electrode (SE), n-type for electron or p-type of hole injection, can limit injection into MIECs. When the SE is the injecting electrode and is under accumulation, there is little difference from a ME. When the SE acts as the extracting electrode, however, injection into the MIEC can be limited because a fraction of any applied bias must support charge depletion in the semiconductor rather than charge injection into the MIEC. In a ME/MIEC/SE system, this can lead to significant asymmetry in current-voltage and injected charge-voltage behavior.

  8. Effective Topological Charge Cancelation Mechanism

    Science.gov (United States)

    Mesarec, Luka; Góźdź, Wojciech; Iglič, Aleš; Kralj, Samo

    2016-06-01

    Topological defects (TDs) appear almost unavoidably in continuous symmetry breaking phase transitions. The topological origin makes their key features independent of systems’ microscopic details; therefore TDs display many universalities. Because of their strong impact on numerous material properties and their significant role in several technological applications it is of strong interest to find simple and robust mechanisms controlling the positioning and local number of TDs. We present a numerical study of TDs within effectively two dimensional closed soft films exhibiting in-plane orientational ordering. Popular examples of such class of systems are liquid crystalline shells and various biological membranes. We introduce the Effective Topological Charge Cancellation mechanism controlling localised positional assembling tendency of TDs and the formation of pairs {defect, antidefect} on curved surfaces and/or presence of relevant “impurities” (e.g. nanoparticles). For this purpose, we define an effective topological charge Δmeff consisting of real, virtual and smeared curvature topological charges within a surface patch Δς identified by the typical spatially averaged local Gaussian curvature K. We demonstrate a strong tendency enforcing Δmeff → 0 on surfaces composed of Δς exhibiting significantly different values of spatially averaged K. For Δmeff ≠ 0 we estimate a critical depinning threshold to form pairs {defect, antidefect} using the electrostatic analogy.

  9. Laser-Assisted H- Charge Exchange Injection in Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Gorlov, Timofey V [ORNL; Danilov, Viatcheslav V [ORNL; Shishlo, Andrei P [ORNL

    2010-01-01

    The use of stripping foils for charge exchange injection can cause a number of operational problems in high intensity hadron accelerators. A recently proposed three-step method of laser-assisted injection is capable of overcoming these problems. This paper presents advances in the physical model of laser-assisted charge exchange injection of H- beams and covers a wide field of atomic physics. The model allows the calculation of the evolution of an H0 beam taking into account spontaneous emission, field ionization and external electromagnetic fields. Some new data on the hydrogen atom related to the problem are calculated. The numerical calculations in the model use realistic descriptions of laser field and injection beam. Generally, the model can be used for design and optimization of a laser-assisted injection cell within an accelerator lattice. Example calculations of laser-assisted injection for an intermediate experiment at SNS in Oak Ridge and for the PS2 accelerator at CERN are presented. Two different schemes, distinctively characterized by various magnetic fields at the excitation point, are discussed. It was shown that the emittance growth of an injected beam can be drastically decreased by moving excitation point into a strong magnetic field.

  10. Laser-assisted H- charge exchange injection in magnetic fields

    Science.gov (United States)

    Gorlov, T.; Danilov, V.; Shishlo, A.

    2010-05-01

    The use of stripping foils for charge exchange injection can cause a number of operational problems in high intensity hadron accelerators. A recently proposed three-step method of laser-assisted injection is capable of overcoming these problems. This paper presents advances in the physical model of laser-assisted charge exchange injection of H- beams and covers a wide field of atomic physics. The model allows the calculation of the evolution of an H0 beam taking into account spontaneous emission, field ionization, and external electromagnetic fields. Some new data on the hydrogen atom related to the problem are calculated. The numerical calculations in the model use realistic descriptions of laser field and injection beam. Generally, the model can be used for design and optimization of a laser-assisted injection cell within an accelerator lattice. Example calculations of laser-assisted injection for an intermediate experiment at SNS in Oak Ridge and for the PS2 accelerator at CERN are presented. Two different schemes, distinctively characterized by various magnetic fields at the excitation point, are discussed. It was shown that the emittance growth of an injected beam can be drastically decreased by moving the excitation point into a strong magnetic field.

  11. Plastification en injection des polymères fonctionnels et chargés

    OpenAIRE

    Pham, Thuy Linh

    2013-01-01

    The main objective of the thesis is modelling and visualization of the phenomena of polymer plastication in the injection-moulding process. In injection moulding or in extrusion, plastication is the step during which polymer pellets are melted by the means of mechanical dissipation provided by a rotating screw and by thermal conduction coming from a heated metallic barrel. This step is crucial for melt thermal homogeneity, charge dispersion and fibre length preservation. Although there have b...

  12. To what extent can charge localization influence electron injection efficiency at graphene-porphyrin interfaces?

    KAUST Repository

    Mohammed, Omar F.

    2015-04-28

    Controlling the electron transfer process at donor- acceptor interfaces is a research direction that has not yet seen much progress. Here, with careful control of the charge localization on the porphyrin macrocycle using β -Cyclodextrin as an external cage, we are able to improve the electron injection efficiency from cationic porphyrin to graphene carboxylate by 120% . The detailed reaction mechanism is also discussed.

  13. Charge injection in an LED with a hybrid composite as the emissive layer

    International Nuclear Information System (INIS)

    Understanding and controlling charge transport are crucial to achieve optimized organic devices, including light emitting diodes. In this study, we investigate the charge injection in devices made with a hybrid composite (HC) containing Zn2SiO4:Mn (ZSP:Mn) in a polymeric blend consisting of poly(o-methoxyaniline) (POMA) and poly(vinylidene co-trifluorethylene) P(VDFTrFE), with the architecture ITO/HC/metallic electrode (ME). Charge injection was found to depend mainly on the POMA semiconducting phase. For ITO/HC/Au, an Ohmic junction was observed because the work function of ITO is close to that of Au, which also matches the energy levels of HC. Holes are injected through the HC/Au junction, as the highest occupied molecular orbital (HOMO) level of POMA matches the Fermi level of Au. The impedance spectroscopy data for the ITO/HC/ME devices were analyzed with a theoretical model where charge injection was assumed to occur via hopping with a distribution of potential energy barriers. The average hopping distance was estimated as 5.5 A and only the device with the Al electrode had the current limited by the interface mechanism (charge injection). For ITO/HC/Cu and ITO/HC/Au devices the limiting factor for the charge transport was the bulk resistance of the samples, in spite of the existence of a small interface energy barrier. The disorder parameter was 0.18 and 0.19 for the HC/Cu and HC/Al interfaces, respectively, which arises from the disordered nature of the hybrid material. The combination of the Cole-Cole model and the Miller-Abrahams function are a good approach to describe charge a.c. injection processes in disordered materials.

  14. Charge states of ions, and mechanisms of charge ordering transitions

    International Nuclear Information System (INIS)

    To gain insight into the mechanism of charge ordering transitions, which conventionally are pictured as a disproportionation of an ion M as 2Mn+→M(n+1)+ + M(n−1)+, we (1) review and reconsider the charge state (or oxidation number) picture itself, (2) introduce new results for the putative charge ordering compound AgNiO2 and the dual charge state insulator AgO, and (3) analyze the cationic occupations of the actual (not formal) charge, and work to reconcile the conundrums that arise. We establish that several of the clearest cases of charge ordering transitions involve no disproportion (no charge transfer between the cations, and hence no charge ordering), and that the experimental data used to support charge ordering can be accounted for within density functional-based calculations that contain no charge transfer between cations. We propose that the charge state picture retains meaning and importance, at least in many cases, if one focuses on Wannier functions rather than atomic orbitals. The challenge of modeling charge ordering transitions with model Hamiltonians isdiscussed. (paper)

  15. Charge injection and transport in fluorene-based copolymers.

    Science.gov (United States)

    Fong, Hon Hang; Malliaras, George G.; Lu, Tianjian; Dunlap, David

    2007-03-01

    Fluorene-based copolymer is considered to be one of the most promising hole transporting and blue light-emitting conjugated polymers used in polymeric light-emitting diodes (PLEDs). Time-of-flight (TOF) technique has been employed to evaluate the charge drift mobility under a temperature range between 200 - 400 K at the thick film regime (1-10 micron). Meanwhile, contact ohmicity is studied by Dark Current Space Charge Limited Conduction (DISCLC) technique. Charge injection efficiencies from different electrical contacts are also studied and the corresponding injection barriers are independently investigated by photoemission and electroabsorption spectroscopies. Results show that the copolymers exhibit non-dispersive charge transport behavior and possess superior mobilities of up to 0.01cm^2V-1s-1 while single-carrier devices from various electrical contacts such as PEDOT:PSS are varied, depending on the chemical structure of amine component in the fluorene-triarylamine copolymers. Results will shed light on the enhancement of device efficiency and stability in the future polymer electronic devices.

  16. Method and Circuit for Injecting a Precise Amount of Charge onto a Circuit Node

    Science.gov (United States)

    Hancock, Bruce R. (Inventor)

    2016-01-01

    A method and circuit for injecting charge into a circuit node, comprising (a) resetting a capacitor's voltage through a first transistor; (b) after the resetting, pre-charging the capacitor through the first transistor; and (c) after the pre-charging, further charging the capacitor through a second transistor, wherein the second transistor is connected between the capacitor and a circuit node, and the further charging draws charge through the second transistor from the circuit node, thereby injecting charge into the circuit node.

  17. Improved charge injection of pentacene transistors by immobilizing DNA on gold source-drain electrodes

    Science.gov (United States)

    Gui, Haiyang; Wei, Bin; Zhang, Jianhua; Wang, Jun

    2014-06-01

    We successfully optimized the charge injection of pentacene-based organic thin-film transistors with bottom contact by immobilizing deoxyribonucleic acid (DNA) on gold electrodes. The single-stranded DNA having mercapto group (-SH) was used as the modified layer by molecular self-assembly onto the surface of gold electrodes. The threshold voltage is -10 V, and the field-effect mobility reaches 0.34 cm2/V s, which is comparable with that of typical top-contact devices. Mechanism of performance improvement is due to the high carrier density in contact region attracted by the phosphate group on the DNA backbone increasing the tunneling probability for improved charge injection. Furthermore, the introduction of modified layer significantly enhanced the grain size of pentacene that is beneficial for charge transport, which also is responsible for the improved device performances.

  18. Analytical Evaluation of the Ratio Between Injection and Space-Charge Limited Currents in Single Carrier Organic Diodes

    OpenAIRE

    Alvarez, Angel Luis; Arredondo, Belen; Romero, Beatriz; Quintana Arregui, Patxi Xabier; Gutierrez Llorente, Araceli; Mallavia, Ricardo; Otón Sánchez, José Manuel

    2008-01-01

    An analytical, complete framework to describe the current-voltage (I-V) characteristics of organic diodes without the use of previous approaches, such as injection or bulk-limited conduction is proposed. Analytical expressions to quantify the ratio between injection and space-charge-limited current from experimental I-V characteristics in organic diodes have been derived. These are used to propose a numerical model in which both bulk transport and injection mechanisms are considered simultane...

  19. Switchable Charge Injection Barrier in an Organic Supramolecular Semiconductor.

    Science.gov (United States)

    Gorbunov, Andrey V; Haedler, Andreas T; Putzeys, Tristan; Zha, R Helen; Schmidt, Hans-Werner; Kivala, Milan; Urbanavičiu̅tė, Indre; Wübbenhorst, Michael; Meijer, E W; Kemerink, Martijn

    2016-06-22

    We disclose a supramolecular material that combines semiconducting and dipolar functionalities. The material consists of a discotic semiconducting carbonyl-bridged triarylamine core, which is surrounded by three dipolar amide groups. In thin films, the material self-organizes in a hexagonal columnar fashion through π-stacking of the molecular core and hydrogen bonding between the amide groups. Alignment by an electrical field in a simple metal/semiconductor/metal geometry induces a polar order in the interface layers near the metal contacts that can be reversibly switched, while the bulk material remains nonpolarized. On suitably chosen electrodes, the presence of an interfacial polarization field leads to a modulation of the barrier for charge injection into the semiconductor. Consequently, a reversible switching is possible between a high-resistance, injection-limited off-state and a low-resistance, space-charge-limited on-state. The resulting memory diode shows switchable rectification with on/off ratios of up to two orders of magnitude. This demonstrated multifunctionality of a single material is a promising concept toward possible application in low-cost, large-area, nonvolatile organic memories. PMID:27246280

  20. Spectroscopic investigation of charge injection process in the bulk-heterojunction P3HT:PCBM solar cell

    International Nuclear Information System (INIS)

    The effect of charge injection in solar cells is usually difficult to examine although it is expected to highly affect the solar cell operation. The effect of charge injection on the operation of bulk-heterojunction (BHJ) solar cells made from blend films of poly(3-hexylthiophene) (P3HT) and methanofullerene (PCBM) is studied using a spectroscopic technique combined with modulation of applied bias, termed a device modulation (DM) spectroscopic technique. The DM measurements enable selective detection of spectroscopic signals from injected P3HT polarons. The voltage dependent-DM measurements in the dark condition reveal the starting point bias of charge injection (∝0 V) and the voltage-dependence of the polaron density, directly from the spectroscopic signals. The frequency dependence of DM signals in the dark condition demonstrates that a bimolecular recombination process dominates the loss mechanism for the injected polarons (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Mechanisms for DNA Charge Transport

    OpenAIRE

    Genereux, Joseph C.; Barton, Jacqueline K.

    2010-01-01

    DNA charge transport (CT) chemistry has received considerable attention by scientific researchers over the past 15 years since our first provocative publication on long range CT in a DNA assembly.1,2 This interest, shared by physicists, chemists and biologists, reflects the potential of DNA CT to provide a sensitive route for signaling, whether in the construction of nanoscale biosensors or as an enzymatic tool to detect damage in the genome. Research into DNA CT chemistry began as a quest to...

  2. Mechanism of electric charge formation polyethylene

    International Nuclear Information System (INIS)

    The electric charge formation in irradiated dielectrics is a phenomenon resulting from interaction of radiation with matter. Using pressure-pulse techniques the general mechanism of eletric charge accumulation and space distribution in electron- and gamma-irradiated polyethylene (low and high density) was studied. The relationship between the charge accumulation and structural and radiation-induced defects in polyethylene was established. Results obtained are applied to other organic materials

  3. Controlled Electron Injection into Plasma Accelerators and Space Charge Estimates

    International Nuclear Information System (INIS)

    Plasma based accelerators are capable of producing electron sources which are ultra-compact (a few microns) and high energies (up to hundreds of MeVs) in much shorter distances than conventional accelerators. This is due to the large longitudinal electric field that can be excited without the limitation of breakdown as in RF structures.The characteristic scale length of the accelerating field is the plasma wavelength and for typical densities ranging from 1018 - 1019 cm-3, the accelerating fields and scale length can hence be on the order of 10-100GV/m and 10-40 mu m, respectively. The production of quasimonoenergetic beams was recently obtained in a regime relying on self-trapping of background plasma electrons, using a single laser pulse for wakefield generation. In this dissertation, we study the controlled injection via the beating of two lasers (the pump laser pulse creating the plasma wave and a second beam being propagated in opposite direction) which induce a localized injection of background plasma electrons. The aim of this dissertation is to describe in detail the physics of optical injection using two lasers, the characteristics of the electron beams produced (the micrometer scale plasma wavelength can result in femtosecond and even attosecond bunches) as well as a concise estimate of the effects of space charge on the dynamics of an ultra-dense electron bunch with a large energy spread

  4. SQL Injection Attacks: Techniques and Protection Mechanisms

    Directory of Open Access Journals (Sweden)

    Santosh Soni

    2011-01-01

    Full Text Available When an internet user interacts in web environment by surfing the Net, sending electronic mail messages and participating in online forums lot of data is generated which may have user’s private information. If this information is captured by third party tools and techniques; it may cause a breach in end user privacy. In the Web environment, end user privacy is one of the most controversial legal issues. In this paper issues related to information leakage through SQL injection attacks are presented and protection mechanisms are also discussed.

  5. Polaronic charge transport mechanism in DNA

    OpenAIRE

    Hennig, Dirk; Archilla, Juan F. R.

    2006-01-01

    For the detailed understanding of the conduction mechanism in DNA we use models based on the concept of polaron and breather solutions. We describe how charge transport relies on the coupling of the charge carrying unit to the vibrational modes of DNA allowing for the formation of polaron-like localised states. The mobility of these localised states is discussed particularly in the presence of parametrical and structural disorder inherent to biomolecules. It is demonstrated tha...

  6. Ocean Remote Sensing With A Charge Injection Device (CID) Array

    Science.gov (United States)

    Stewart, S. E.; Buntzen, R. R.

    1984-09-01

    Ocean optical data has been remotely collected using the Advanced Solidstate Array Spectroradiometer (ASAS). ASAS is a multispectral pushbroom scanner with 32 channels extending from 400 to 850 nm. It is built around a 32 by 512 element charge injection device (CID) array with enhanced sensitivity in the blue. Twelve-bit digital output with variable gain and offset in the pre-amp and low system noise give this scanner the ability to pick up low level subsurface upwelling light from the ocean. The scanner was built by General Electric and the NASA Johnson Space Center with optics from TRW under a Naval Ocean Systems Center program for ocean remote sensing. It was first flown with the detector uncooled in September of 1983 at the Naval Coastal Systems Center in Panama City, Florida. Preliminary analysis of the data indicates a signal-to-noise ratio of at least 200 to 1. Subsequent image processing and refinements in the scanner hardware promise to improve this figure significantly. Details of the scanner design, calibration, and noise reduction will be presented. The scan-ner's potential for use in shallow water bottom mapping and chlorophyll determination will be discussed. Fi-nally, projected improvements in the scanner and its performance will be described.

  7. Experimental and Theoretical Characterization of Artificial Muscles Based on Charge Injection in Carbon Nanotubes

    Science.gov (United States)

    Baughman, Ray

    2002-03-01

    We theoretically predicted that carbon nanotubes have the potential of providing at least an order of magnitude higher work capacity per cycle and stress generation capability, as compared with any prior-art material for directly converting electrical energy to mechanical energy. Experimental and theoretical results expand understanding of the nanotube actuation mechanism, and demonstrate that improvements in nanotube sheet and macrofiber properties correspondingly increase actuator performance. The actuation mechanism is electrochemical double-layer charge injection, which we show is dominated by band structure effects for low degrees of charge transfer and by intra-tube electrostatic repulsion when charge transfer is large. Measurements indicate that charge transfer is limited to the outer nanotubes in a nanotube bundle, which limits present performance (as does creep, nanotube misalignment, and poor inter-bundle stress transfer). Nevertheless, measured actuation stresses are 100 times that of natural muscle, and the measured gravimetric work-per-cycle (fixed load condition) is already much higher than for the hard ferroelectrics. Efforts to eliminate these problems (via debundling, nanotube welding, and improvements in nanotube spinning methods) will be described, together with the initial demonstration and analysis of chemically powered carbon nanotube muscles.

  8. Charge Accretion Rate and Injection Radius of Ionized-Induced Injections in Laser Wakefield Accelerators

    Science.gov (United States)

    Zeng, Ming; Chen, Min; Sheng, Zheng-Ming

    2016-03-01

    Ionization-induced injection has recently been proved to be a stable injection method with several advantages in laser wakefield accelerators. However, the controlling of this injection process aiming at producing high quality electron beams is still challenging. In this paper, we examine the ionization injection processes and estimate the injection rate with two-dimensional particle-in-cell simulations. The injection rate is shown to increase linearly with the high-Z gas density as long as its ratio is smaller than some threshold in the mix gases. It is also shown that by changing the transverse mode of the driving lasers one can control the injection rate.

  9. Tuning The Optical, Charge Injection, and Charge Transport Properties of Organic Electronic Devices

    Science.gov (United States)

    Zalar, Peter

    Since the early 1900's, synthetic insulating polymers (plastics) have slowly taken over the role that traditional materials like wood or metal have had as basic components for construction, manufactured goods, and parts. Plastics allow for high throughput, low temperature processing, and control of bulk properties through molecular modifications. In the same way, pi-conjugated organic molecules are emerging as a possible substitute for inorganic materials due to their electronic properties. The semiconductive nature of pi-conjugated materials make them an attractive candidate to replace inorganic materials, primarily due to their promise for low cost and large-scale production of basic semiconducting devices such as light-emitting diodes, solar cells, and field-effect transistors. Before organic semiconductors can be realized as a commercial product, several hurdles must be cleared. The purpose of this dissertation is to address three distinct properties that dominate the functionality of devices harnessing these materials: (1) optical properties, (2) charge injection, and (3) charge transport. First, it is shown that the electron injection barrier in the emissive layer of polymer light-emitting diodes can be significantly reduced by processing of novel conjugated oligoelectrolytes or deoxyribonucleic acid atop the emissive layer. Next, the charge transport properties of several polymers could be modified by processing them from solvents containing small amounts of additives or by using regioregular and enantiopure chemical structures. It is then demonstrated that the optical and electronic properties of Lewis basic polymer structures can be readily modified by interactions with strongly electron-withdrawing Lewis acids. Through red-shifted absorption, photoluminescence, and electroluminescence, a single pi-conjugated backbone can be polychromatic. In addition, interaction with Lewis acids can remarkably p-dope the hole transport of the parent polymer, leading to a

  10. The first test experiment of H- charge-exchange injection in the KEK booster

    International Nuclear Information System (INIS)

    The H- charge-exchange injection method was applied to the 500 MeV booster of the 12 GeV proton synchrotron at KEK, as an alternative to the multi-turn injection method using direct injection of protons. The first test experiment of such injection was carried out during three weeks beginning in late September 1983. Experimental results showed that, in spite of the low injection energy used for our booster, such an injection method is promising for increasing the beam intensity of the booster. And also, some further improvements are proposed. (author)

  11. Efficient barrier for charge injection in polyethylene by silver nanoparticles/plasma polymer stack

    International Nuclear Information System (INIS)

    Charge injection from a metal/insulator contact is a process promoting the formation of space charge in polymeric insulation largely used in thick layers in high voltage equipment. The internal charge perturbs the field distribution and can lead to catastrophic failure either through its electrostatic effects or through energetic processes initiated under charge recombination and/or hot electrons effects. Injection is still ill-described in polymeric insulation due to the complexity of the contact between the polymer chains and the electrodes. Barrier heights derived from the metal work function and the polymer electronic affinity do not provide a good description of the measurements [Taleb et al., IEEE Trans. Dielectr. Electr. Insul. 20, 311–320 (2013)]. Considering the difficulty to describe the contact properties and the need to prevent charge injection in polymers for high voltage applications, we developed an alternative approach by tailoring the interface properties by the silver nanoparticles (AgNPs)/plasma polymer stack, deposited on the polymer film. Due to their small size, the AgNPs, covered by a very thin film of plasma polymer, act as deep traps for the injected charges thereby stabilizing the interface from the point of view of charge injection. After a quick description of the method for elaborating the nanostructured layer near the contact, it is demonstrated how the AgNPs/plasma polymer stack effectively prevents, in a spectacular way, the formation of bulk space charge.

  12. Efficient barrier for charge injection in polyethylene by silver nanoparticles/plasma polymer stack

    Energy Technology Data Exchange (ETDEWEB)

    Milliere, L. [LAPLACE (Laboratoire Plasma et Conversion d' Energie), Université de Toulouse, UPS, INPT, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); Makasheva, K., E-mail: kremena.makasheva@laplace.univ-tlse.fr; Laurent, C.; Despax, B.; Teyssedre, G. [LAPLACE (Laboratoire Plasma et Conversion d' Energie), Université de Toulouse, UPS, INPT, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France)

    2014-09-22

    Charge injection from a metal/insulator contact is a process promoting the formation of space charge in polymeric insulation largely used in thick layers in high voltage equipment. The internal charge perturbs the field distribution and can lead to catastrophic failure either through its electrostatic effects or through energetic processes initiated under charge recombination and/or hot electrons effects. Injection is still ill-described in polymeric insulation due to the complexity of the contact between the polymer chains and the electrodes. Barrier heights derived from the metal work function and the polymer electronic affinity do not provide a good description of the measurements [Taleb et al., IEEE Trans. Dielectr. Electr. Insul. 20, 311–320 (2013)]. Considering the difficulty to describe the contact properties and the need to prevent charge injection in polymers for high voltage applications, we developed an alternative approach by tailoring the interface properties by the silver nanoparticles (AgNPs)/plasma polymer stack, deposited on the polymer film. Due to their small size, the AgNPs, covered by a very thin film of plasma polymer, act as deep traps for the injected charges thereby stabilizing the interface from the point of view of charge injection. After a quick description of the method for elaborating the nanostructured layer near the contact, it is demonstrated how the AgNPs/plasma polymer stack effectively prevents, in a spectacular way, the formation of bulk space charge.

  13. Minimizing electrode edge in organic transistors with ultrathin reduced graphene oxide for improving charge injection efficiency.

    Science.gov (United States)

    Xu, Zeyang; Chen, Xiaosong; Zhang, Suna; Wu, Kunjie; Li, Hongwei; Meng, Yancheng; Li, Liqiang

    2016-05-11

    Electrode materials and geometry play a crucial role in the charge injection efficiency in organic transistors. Reduced graphene oxide (RGO) electrodes show good compatibility with an organic semiconductor from the standpoint of energy levels and ordered growth of the organic semiconductor, both of which are favourable for charge injection. However, the wide electrode edge (>10 nm) in commonly-used RGO electrodes is generally detrimental to charge injection. In this study, ultrathin (about 3 nm) RGO electrodes are fabricated via a covalency-based assembly strategy, which has advantages such as robustness against solvents, high conductivity, transparency, and easy scaling-up. More remarkably, the ultrathin electrode fabricated in this study has a narrow edge, which may facilitate the diffusion and assembly of organic semiconductors and thus form a uniform semiconductor film across the electrode/channel junction area. As a result, the minimized electrode edge may significantly improve the charge injection in organic transistors compared with thick electrodes. PMID:27062997

  14. Charge injection E/D MESFET structures for high speed and low power applications

    OpenAIRE

    Masera, G; Piccinini, G.; Ruo Roch, M.; Zamboni, M

    1998-01-01

    In this paper new dynamic charge injection E/D logics are presented and compared with traditional dynamic ones such as TDFL (Two Phase Dynamic Fet Logic). The main drawbacks of TDFL will be analyzed together with the advantages offered with respect to the static DCFL based topologies; a tentative structure has been derived (MTDFL - Modified TDFL) to comply with the VLSI requirements; then the advantages of the charge injection principles applied to the design of new logic topologies are inspe...

  15. Charge injection from a surface depletion region—The Al 2O 3-silicon system

    Science.gov (United States)

    Kolk, J.; Heasell, E. L.

    1980-03-01

    Electron injection from a surface depletion region, over the surface barrier at an Al 2O 3-silicon interface is studied. The current passing over the barrier is measured by observing the rate of flat-band voltage shift as charge is trapped in the oxide. The data obtained is compared with the predictions of present models for charge injection. It is found that the so-called 'lucky-electron' model gives the most generally satisfactory agreement with the observations.

  16. Impact of charge carrier injection on single-chain photophysics of conjugated polymers

    CERN Document Server

    Hofmann, Felix J; Lupton, John M

    2016-01-01

    Charges in conjugated polymer materials have a strong impact on the photophysics and their interaction with the primary excited state species has to be taken into account in understanding device properties. Here, we employ single-molecule spectroscopy to unravel the influence of charges on several photoluminescence (PL) observables. The charges are injected either stochastically by a photochemical process, or deterministically in a hole-injection sandwich device configuration. We find that upon charge injection, besides a blue-shift of the PL emission and a shortening of the PL lifetime due to quenching and blocking of the lowest-energy chromophores, the non-classical photon arrival time distribution of the multichromophoric chain is modified towards a more classical distribution. Surprisingly, the fidelity of photon antibunching deteriorates upon charging, whereas one would actually expect the number of chromophores to be reduced. A qualitative model is presented to explain the observed PL changes. The resul...

  17. Raising the barrier for photoinduced DNA charge injection with a cyclohexyl artificial base pair.

    Science.gov (United States)

    Singh, Arunoday P N; Harris, Michelle A; Young, Ryan M; Miller, Stephen A; Wasielewski, Michael R; Lewis, Frederick D

    2015-01-01

    The effects of an artificial cyclohexyl base pair on the quantum yields of fluorescence and dynamics of charge separation and charge recombination have been investigated for several synthetic DNA hairpins. The hairpins possess stilbenedicarboxamide, perylenediimide, or naphthalenediimide linkers and base-paired stems. In the absence of the artificial base pair hole injection into both adenine and guanine purine bases is exergonic and irreversible, except in the case of stilbene with adenine for which it is slightly endergonic and reversible. Insertion of the artificial base pair renders hole injection endergonic or isoergonic except in the case of the powerful naphthalene acceptor for which it remains exergonic. Both hole injection and charge recombination are slower for the naphthalene acceptor in the presence of the artificial base pair than in its absence. The effect of an artificial base pair on charge separation and charge recombination in hairpins possessing stilbene and naphthalene acceptor linkers and a stilbenediether donor capping group has also been investigated. In the case of the stilbene acceptor-stilbene donor capped hairpins photoinduced charge separation across six base pairs is efficient in the absence of the artificial base pair but does not occur in its presence. In the case of the naphthalene acceptor-stilbene donor capped hairpins the artificial base pair slows but does not stop charge separation and charge recombination, leading to the formation of long-lived charge separated states. PMID:26442603

  18. Profiling of the injected charge drift current transients by cross-sectional scanning technique

    Science.gov (United States)

    Gaubas, E.; Ceponis, T.; Pavlov, J.; Baskevicius, A.

    2014-02-01

    The electric field distribution and charge drift currents in Si particle detectors are analyzed. Profiling of the injected charge drift current transients has been implemented by varying charge injection position within a cross-sectional boundary of the particle detector. The obtained profiles of the induction current density and duration of the injected charge drift pulses fit well the simulated current variations. Induction current transients have been interpreted by different stages of the bipolar and monopolar drift of the injected carriers. Profiles of the injected charge current transients registered in the non-irradiated and neutron irradiated Si diodes are compared. It has been shown that the mixed regime of the competing processes of drift, recombination, and diffusion appears in the measured current profiles on the irradiated samples. The impact of the avalanche effects can be ignored based on the investigations presented. It has been shown that even a simplified dynamic model enabled us to reproduce the main features of the profiled transients of induced charge drift current.

  19. Profiling of the injected charge drift current transients by cross-sectional scanning technique

    International Nuclear Information System (INIS)

    The electric field distribution and charge drift currents in Si particle detectors are analyzed. Profiling of the injected charge drift current transients has been implemented by varying charge injection position within a cross-sectional boundary of the particle detector. The obtained profiles of the induction current density and duration of the injected charge drift pulses fit well the simulated current variations. Induction current transients have been interpreted by different stages of the bipolar and monopolar drift of the injected carriers. Profiles of the injected charge current transients registered in the non-irradiated and neutron irradiated Si diodes are compared. It has been shown that the mixed regime of the competing processes of drift, recombination, and diffusion appears in the measured current profiles on the irradiated samples. The impact of the avalanche effects can be ignored based on the investigations presented. It has been shown that even a simplified dynamic model enabled us to reproduce the main features of the profiled transients of induced charge drift current

  20. Profiling of the injected charge drift current transients by cross-sectional scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Gaubas, E., E-mail: eugenijus.gaubas@ff.vu.lt; Ceponis, T.; Pavlov, J.; Baskevicius, A. [Institute of Applied Research, Vilnius University, Sauletekio av. 9-III, LT-10222 Vilnius (Lithuania)

    2014-02-07

    The electric field distribution and charge drift currents in Si particle detectors are analyzed. Profiling of the injected charge drift current transients has been implemented by varying charge injection position within a cross-sectional boundary of the particle detector. The obtained profiles of the induction current density and duration of the injected charge drift pulses fit well the simulated current variations. Induction current transients have been interpreted by different stages of the bipolar and monopolar drift of the injected carriers. Profiles of the injected charge current transients registered in the non-irradiated and neutron irradiated Si diodes are compared. It has been shown that the mixed regime of the competing processes of drift, recombination, and diffusion appears in the measured current profiles on the irradiated samples. The impact of the avalanche effects can be ignored based on the investigations presented. It has been shown that even a simplified dynamic model enabled us to reproduce the main features of the profiled transients of induced charge drift current.

  1. DESIGN AND MECHANICAL INTEGRITY OF CO2 INJECTION WELLS

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2011-12-01

    Full Text Available Geologic Sequestration (GS is part of a process known as “carbon capture and storage (CCS” and represents the process of injecting CO2, into deep subsurface rock formations for long-term storage. For injecting of CO2 existing wells are used as well as new drilled wells. A well represents the most likely route for leakage of CO2 from geologic carbon sequestration. Maintaining mechanical integrity helps prevent the well and wellbore from becoming conduits for CO2 migration out of the injection zone. The typical components of a CO2 injection well are casing, tubing, cement, and packer. These components are relevant for maintaining mechanical integrity and ensuring CO2 does not migrate upwards from the injection zone into underground source of drinking water (USDW; therefore helping to ensure zonal isolation of the injected carbon dioxide. In order to have the safe underground storage of CO2 well integrity considerations should be present during all phases of well life including design phase, drilling, completion, injection, workover (service and abandonment. The paper describes well design, well integrity and mechanical integrity tests (MITs as a means of measuring the adequacy of the construction of the injection well and as a way to detect problems within the well system.

  2. Dynamic mechanical properties of parts from multicavity injection mould

    OpenAIRE

    E. Bociąga; T. Jaruga

    2007-01-01

    Purpose: The examination of dynamic mechanical properties of injection moulded parts, obtained from different cavities of injection mould, was the purpose of this research. The parts were manufactured from polypropylene.Design/methodology/approach: The testing method used was DMTA – “Dynamic Mechanical Thermal Analysis” – which is often used to determine the properties of polymers, blends and composites as well as the manufactured parts.Findings: The differences in storage modulus E’ and loss...

  3. Electron trapping mechanisms in magnetron injection guns

    Science.gov (United States)

    Pagonakis, Ioannis Gr.; Piosczyk, Bernhard; Zhang, Jianhua; Illy, Stefan; Rzesnicki, Tomasz; Hogge, Jean-Philippe; Avramidis, Konstantinos; Gantenbein, Gerd; Thumm, Manfred; Jelonnek, John

    2016-02-01

    A key parameter for the gyrotron operation and efficiency is the presence of trapped electrons. Two electron trapping mechanisms can take place in gyrotrons: (i) the adiabatic trap and (ii) the magnetic potential well. Their influence on the gyrotron operation is analyzed. Two gun design criteria are then proposed to suppress both mechanisms in order to minimize the risk of possible problems. Experimental results of three high power gyrotrons are presented and their performance is correlated to the presence of populations of trapped electrons. Finally, some very general gun design principles are presented for the limitation of harmful electron trapping.

  4. A Method to Overcome Space Charge at Injection

    Energy Technology Data Exchange (ETDEWEB)

    Ya. Derbenev

    2005-09-29

    The transverse space charge forces in a high current, low energy beam can be reduced by mean of a large increase of the beam's transverse sizes while maintaining the beam area in the 4D phase space. This can be achieved by transforming the beam area in phase space of each of two normal 2D transverse (either plane or circular) modes from a spot shape into a narrow ring of a large amplitude, but homogeneous in phase. Such a transformation results from the beam evolution in the island of a dipole resonance when the amplitude width of the island shrinks adiabatically. After stacking (by using stripping foils or cooling) the beam in such a state and accelerating to energies sufficiently high that the space charge becomes insignificant, the beam then can be returned back to a normal spot shape by applying the reverse transformation. An arrangement that can provide such beam gymnastics along a transport line after a linac and before a booster and/or in a ring with circulating beam will be described and numerical estimates will be presented. Other potential applications of the method will be briefly discussed.

  5. A Method to Overcome Space Charge at Injection

    International Nuclear Information System (INIS)

    The transverse space charge forces in a high current, low energy beam can be reduced by mean of a large increase of the beam's transverse sizes while maintaining the beam area in the 4D phase space. This can be achieved by transforming the beam area in phase space of each of two normal 2D transverse (either plane or circular) modes from a spot shape into a narrow ring of a large amplitude, but homogeneous in phase. Such a transformation results from the beam evolution in the island of a dipole resonance when the amplitude width of the island shrinks adiabatically. After stacking (by using stripping foils or cooling) the beam in such a state and accelerating to energies sufficiently high that the space charge becomes insignificant, the beam then can be returned back to a normal spot shape by applying the reverse transformation. An arrangement that can provide such beam gymnastics along a transport line after a linac and before a booster and/or in a ring with circulating beam will be described and numerical estimates will be presented. Other potential applications of the method will be briefly discussed

  6. Formation of charged nanoparticles in hydrocarbon flames: principal mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Starik, A M; Savel' ev, A M; Titova, N S [Central Institute of Aviation Motors, 2 Aviamotornaya st., 111116 Moscow (Russian Federation)], E-mail: star@ciam.ru

    2008-11-01

    The processes of charged gaseous and particulate species formation in sooting hydrocarbon/air flame are studied. The original kinetic model, comprising the chemistry of neutral and charged gaseous species, generation of primary clusters, which then undergo charging due to attachment of ions and electrons to clusters and via thermoemission, and coagulation of charged-charged, charged-neutral and neutral-neutral particles, is reported. The analysis shows that the principal mechanisms of charged particle origin in hydrocarbon flames are associated with the attachment of ions and electrons produced in the course of chemoionization reactions to primary small clusters and particles and coagulation via charged-charged and charged-neutral particle interaction. Thermal ionization of particles does not play a significant role in the particle charging.

  7. Formation of charged nanoparticles in hydrocarbon flames: principal mechanisms

    Science.gov (United States)

    Starik, A. M.; Savel'ev, A. M.; Titova, N. S.

    2008-11-01

    The processes of charged gaseous and particulate species formation in sooting hydrocarbon/air flame are studied. The original kinetic model, comprising the chemistry of neutral and charged gaseous species, generation of primary clusters, which then undergo charging due to attachment of ions and electrons to clusters and via thermoemission, and coagulation of charged-charged, charged-neutral and neutral-neutral particles, is reported. The analysis shows that the principal mechanisms of charged particle origin in hydrocarbon flames are associated with the attachment of ions and electrons produced in the course of chemoionization reactions to primary small clusters and particles and coagulation via charged-charged and charged-neutral particle interaction. Thermal ionization of particles does not play a significant role in the particle charging. This paper was presented at the Third International Symposium on Nonequilibrium Process, combustion, and Atmospheric Phenomena (Dagomys, Sochi, Russia, 25-29 June 2007).

  8. Formation of charged nanoparticles in hydrocarbon flames: principal mechanisms

    International Nuclear Information System (INIS)

    The processes of charged gaseous and particulate species formation in sooting hydrocarbon/air flame are studied. The original kinetic model, comprising the chemistry of neutral and charged gaseous species, generation of primary clusters, which then undergo charging due to attachment of ions and electrons to clusters and via thermoemission, and coagulation of charged-charged, charged-neutral and neutral-neutral particles, is reported. The analysis shows that the principal mechanisms of charged particle origin in hydrocarbon flames are associated with the attachment of ions and electrons produced in the course of chemoionization reactions to primary small clusters and particles and coagulation via charged-charged and charged-neutral particle interaction. Thermal ionization of particles does not play a significant role in the particle charging.

  9. Longitudinal painting schemes for H- charge exchange injection into the PS2

    CERN Document Server

    Benedikt, M; Hancock, S; Knünz, V; Vonderhaid, I

    2010-01-01

    Minimization of direct space charge tune shift at injection into the PS2 is important for the reduction of beam losses. A determining parameter for the tune shift is the bunching factor, defined as mean current over peak current for one RF period. Various longitudinal painting schemes for PS2 injection, all based on synchrotron motion, have been studied with respect to the resulting bunching factors.

  10. Dispersion Matching of a Space Charge dominated Beam at Injection into the CERN PS Booster

    CERN Document Server

    Hanke, Klaus; Scrivens, Richard

    2005-01-01

    In order to match the dispersion at injection into the CERN PS Booster, the optics of the injection line was simulated using two different codes (MAD and TRACE). The simulations were benchmarked versus experimental results. The model of the line was then used to re-match the dispersion. Experimental results are presented for different optics of the line. Measurements with varying beam current show the independence of the measured quantity of space-charge effects.

  11. Charge exchange momentum transfer due to ion beam injection in partially ionized plasmas

    International Nuclear Information System (INIS)

    Time responses of a helium plasma to helium gas puffing without and with helium beam injection in a linear plasma device are experimentally investigated. Increase in the neutral density due to gas puffing is suppressed by ion beam injection. The experimental results show that a momentum transport from the ion beam to the puffed neutral particles occurs due to the charge exchange interaction, suggesting that charge exchange momentum transport is one of the processes responsible for the spatial redistribution of neutral atoms in partially ionized plasmas. (author)

  12. Space charge effects in axial injection line for U-400 cyclotron

    International Nuclear Information System (INIS)

    The space charge influence on the beam dynamics in transport line is studied by the method of the distribution moments. Fifteen equations describing dependence of the first and second order moments (average transverse beam sizes and velocities, cross terms) on longitudinal coordinate are solved numerically. For particular U-400 cyclotron injection line the value of current which produces significant effect on beam dynamics is defined. It is shown that space charge effects can be compensated by proper readjusting of the solenoid strengths

  13. Impact of charge carrier injection on single-chain photophysics of conjugated polymers

    Science.gov (United States)

    Hofmann, Felix J.; Vogelsang, Jan; Lupton, John M.

    2016-06-01

    Charges in conjugated polymer materials have a strong impact on the photophysics and their interaction with the primary excited state species has to be taken into account in understanding device properties. Here, we employ single-molecule spectroscopy to unravel the influence of charges on several photoluminescence (PL) observables. The charges are injected either stochastically by a photochemical process or deterministically in a hole-injection sandwich device configuration. We find that upon charge injection, besides a blue-shift of the PL emission and a shortening of the PL lifetime due to quenching and blocking of the lowest-energy chromophores, the non-classical photon arrival time distribution of the multichromophoric chain is modified towards a more classical distribution. Surprisingly, the fidelity of photon antibunching deteriorates upon charging, whereas one would actually expect the opposite: the number of chromophores to be reduced. A qualitative model is presented to explain the observed PL changes. The results are of interest to developing a microscopic understanding of the intrinsic charge-exciton quenching interaction in devices.

  14. Mechanical properties of micro-injected HDPE composites

    Science.gov (United States)

    Bongiorno, A.; Pagano, C.; Agnelli, S.; Baldi, F.; Fassi, I.

    2016-03-01

    Micro-injection moulding is one of the key manufacturing technologies for the mass production of high value polymeric miniaturized-components. However, this process is not just a straightforward down scaling of the conventional injection moulding technique. Indeed, during the micro-injection the polymer melt is forced to flow at high strain rates through very small channels in non-isothermal conditions, and this can lead to complex microstructures and to parts with unexpected performances. In this work, the relationships among the processing conditions, the mechanical properties and the microstructural characteristics of miniaturized specimens obtained by injection moulding were investigated. Two model systems were considered with the same filler content of 15% wt. (HDPE-talc and HDPE-glass beads), representative of two different types of micro-composites: containing lamellar and spherical micro-particles, respectively. The attention was focused on the influence of the filler type and the process conditions on the mechanical behaviour, examined by uniaxial tensile tests and dynamic-mechanical analyses, and on the morphological characteristics of the specimens, examined by microscopy analyses. The results highlight that mechanical response of the miniaturized specimens is significantly affected by both the filler and the process conditions that can have an influence on the polymer microstructure. Lamellar composites showed the best performance due to the orientation of the talc particles during the micro-injection process, while, different morphologies of the skin/core transition region in dependence on the process temperatures were observable.

  15. Mechanistic Studies of Charge Injection from Metallic Electrodes into Organic Semiconductors Mediated by Ionic Functionalities: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thuc-Quyen [UCSB; Bazan, Guillermo [UCSB; Mikhailovsky, Alexander [UCSB

    2014-04-15

    Metal-organic semiconductor interfaces are important because of their ubiquitous role in determining the performance of modern electronics such as organic light emitting diodes (OLEDs), fuel cells, batteries, field effect transistors (FETs), and organic solar cells. Interfaces between metal electrodes required for external wiring to the device and underlying organic structures directly affect the charge carrier injection/collection efficiency in organic-based electronic devices primarily due to the mismatch between energy levels in the metal and organic semiconductor. Environmentally stable and cost-effective electrode materials, such as aluminum and gold typically exhibit high potential barriers for charge carriers injection into organic devices leading to increased operational voltages in OLEDs and FETs and reduced charge extraction in photovoltaic devices. This leads to increased power consumption by the device, reduced overall efficiency, and decreased operational lifetime. These factors represent a significant obstacle for development of next generation of cheap and energy-efficient components based on organic semiconductors. It has been noticed that introduction of organic materials with conjugated backbone and ionic pendant groups known as conjugated poly- and oligoelectrolytes (CPEs and COEs), enables one to reduce the potential barriers at the metal-organic interface and achieve more efficient operation of a device, however exact mechanisms of the phenomenon have not been understood. The goal of this project was to delineate the function of organic semiconductors with ionic groups as electron injection layers. The research incorporated a multidisciplinary approach that encompassed the creation of new materials, novel processing techniques, examination of fundamental electronic properties and the incorporation of the resulting knowledgebase into development of novel organic electronic devices with increased efficiency, environmental stability, and reduced

  16. Maximal charge injection of consecutive electron pulses with uniform temporal pulse separation

    International Nuclear Information System (INIS)

    A charge sheet model is proposed for the study of the space-charge limited density of consecutive electron pulses injected to in a diode with uniform temporal pulse separation. Based on the model, an analytical formula is derived for expressing the dependency of the charge density limit on the gap spacing, gap voltage, and pulse separation. The theoretical results are verified by numerical solutions up to electron energy of a few MeV, including relativistic effects. The model can be applied to the design of multiple-pulse electron beams for time resolved electron microscopy and free electron lasers

  17. Charge Injection and Transport in Metal/Polymer Chains/Metal Sandwich Structure

    Institute of Scientific and Technical Information of China (English)

    LI Hai-Hong; LI Dong-Mei; LI Yuan; GAO Kun; LIU De-Sheng; XIE Shi-Jie

    2008-01-01

    @@ Using the tight-binding Su-Schrieffer-Heeger model and a nonadiabatic dynamic evolution method, we study the dynamic processes of the charge injection and transport in a metal/two coupled conjugated polymer chains/metal structure. It is found that the charge interchain transport is determined by the strength of the electric field and the magnitude of the voltage bias applied on the metal electrode. The stronger electric field and the larger voltage bias are both in favour of the charge interchain transport.

  18. Silver nanoparticles as a key feature of a plasma polymer composite layer in mitigation of charge injection into polyethylene under dc stress

    Science.gov (United States)

    Milliere, L.; Maskasheva, K.; Laurent, C.; Despax, B.; Boudou, L.; Teyssedre, G.

    2016-01-01

    The aim of this work is to limit charge injection from a semi-conducting electrode into low density polyethylene (LDPE) under dc field by tailoring the polymer surface using a silver nanoparticles-containing layer. The layer is composed of a plane of silver nanoparticles embedded in a semi-insulating organosilicon matrix deposited on the polyethylene surface by a plasma process. Size, density and surface coverage of the nanoparticles are controlled through the plasma process. Space charge distribution in 300 μm thick LDPE samples is measured by the pulsed-electroacoustic technique following a short term (step-wise voltage increase up to 50 kV mm-1, 20 min in duration each, followed by a polarity inversion) and a longer term (up to 12 h under 40 kV mm-1) protocols for voltage application. A comparative study of space charge distribution between a reference polyethylene sample and the tailored samples is presented. It is shown that the barrier effect depends on the size distribution and the surface area covered by the nanoparticles: 15 nm (average size) silver nanoparticles with a high surface density but still not percolating form an efficient barrier layer that suppress charge injection. It is worthy to note that charge injection is detected for samples tailored with (i) percolating nanoparticles embedded in organosilicon layer; (ii) with organosilicon layer only, without nanoparticles and (iii) with smaller size silver particles (<10 nm) embedded in organosilicon layer. The amount of injected charges in the tailored samples increases gradually in the samples ranking given above. The mechanism of charge injection mitigation is discussed on the basis of complementary experiments carried out on the nanocomposite layer such as surface potential measurements. The ability of silver clusters to stabilize electrical charges close to the electrode thereby counterbalancing the applied field appears to be a key factor in explaining the charge injection

  19. Charge injection and discharging of Si nanocrystals and arrays by atomic force microscopy

    Science.gov (United States)

    Boer, E.; Ostraat, M.; Brongersma, M. L.; Flagan, R. C.; Atwater, H. A.

    2000-01-01

    Charge injection and storage in dense arrays of silicon nanocrystals in SiO(sub 2) is a critical aspect of the performance of potential nanocrystal flash memory structures. The ultimate goal for this class of devices is few-or single- electron storage in a small number of nanocrystal elements.

  20. Influence of injected charge carriers on photocurrents in polymer solar cells

    NARCIS (Netherlands)

    Wehenkel, Dominique J.; Koster, L. Jan Anton; Wienk, Martijn M.; Janssen, Rene A. J.

    2012-01-01

    We determine and analyze the photocurrent Jph in polymer solar cells under conditions where, no, one, or two different charge carriers can be injected by choosing appropriate electrodes and compare the experimental results to simulations based on a drift-diffusion device model that accounts for phot

  1. In vivo charge injection limits increased after 'unsafe' stimulation

    DEFF Research Database (Denmark)

    Meijs, Suzan; Sørensen, Søren; Rechendorff, Kristian; Rijkhoff, Nico

    The effect of unsafe stimulation on charge injection limits (Qinj) and pulsing capacitance (Cpulse) was investigated. Four stimulation protocols were applied: 20 mA – 200 and 400 Hz, 50 mA – 200 and 400 Hz. Increasing Qinj and Cpulse were observed for all stimulation protocols. Corrosion was not ...

  2. Performance of the CERN PSB at 160 MeV with $H^{-}$ charge exchange injection

    CERN Document Server

    AUTHOR|(CDS)2084247; Santoni, Claudio

    As part of the LHC Injectors Upgrade Project, the CERN PS Booster (PSB) will be upgraded with a H- charge exchange injection system and its injection energy will be raised from 50 MeV to 160 MeV to obtain the beam brightness required for the LHC High-Luminosity Upgrade. Space charge effects like beam losses and transverse emittance blow-up at injection are expected to be the main limitations towards the achievement of the required high brightness. Studies of beam dynamics in presence of space charge in order to evaluate the performances of the PSB after the Upgrade have been performed. The first part of the work consists of measurements in the present machine, to study the effects of space charge and its interplay with resonances and to have a good set of data for code benchmarking. The code chosen for the beam tracking in presence of space charge is PTC-Orbit (and PyOrbit). Necessary numerical convergence studies are presented together with a benchmark with the PSB measurements. Once assessed the code and it...

  3. New Perspectives on the Charging Mechanisms of Supercapacitors.

    Science.gov (United States)

    Forse, Alexander C; Merlet, Céline; Griffin, John M; Grey, Clare P

    2016-05-11

    Supercapacitors (or electric double-layer capacitors) are high-power energy storage devices that store charge at the interface between porous carbon electrodes and an electrolyte solution. These devices are already employed in heavy electric vehicles and electronic devices, and can complement batteries in a more sustainable future. Their widespread application could be facilitated by the development of devices that can store more energy, without compromising their fast charging and discharging times. In situ characterization methods and computational modeling techniques have recently been developed to study the molecular mechanisms of charge storage, with the hope that better devices can be rationally designed. In this Perspective, we bring together recent findings from a range of experimental and computational studies to give a detailed picture of the charging mechanisms of supercapacitors. Nuclear magnetic resonance experiments and molecular dynamics simulations have revealed that the electrode pores contain a considerable number of ions in the absence of an applied charging potential. Experiments and computer simulations have shown that different charging mechanisms can then operate when a potential is applied, going beyond the traditional view of charging by counter-ion adsorption. It is shown that charging almost always involves ion exchange (swapping of co-ions for counter-ions), and rarely occurs by counter-ion adsorption alone. We introduce a charging mechanism parameter that quantifies the mechanism and allows comparisons between different systems. The mechanism is found to depend strongly on the polarization of the electrode, and the choice of the electrolyte and electrode materials. In light of these advances we identify new directions for supercapacitor research. Further experimental and computational work is needed to explain the factors that control supercapacitor charging mechanisms, and to establish the links between mechanisms and performance

  4. New Perspectives on the Charging Mechanisms of Supercapacitors

    Science.gov (United States)

    2016-01-01

    Supercapacitors (or electric double-layer capacitors) are high-power energy storage devices that store charge at the interface between porous carbon electrodes and an electrolyte solution. These devices are already employed in heavy electric vehicles and electronic devices, and can complement batteries in a more sustainable future. Their widespread application could be facilitated by the development of devices that can store more energy, without compromising their fast charging and discharging times. In situ characterization methods and computational modeling techniques have recently been developed to study the molecular mechanisms of charge storage, with the hope that better devices can be rationally designed. In this Perspective, we bring together recent findings from a range of experimental and computational studies to give a detailed picture of the charging mechanisms of supercapacitors. Nuclear magnetic resonance experiments and molecular dynamics simulations have revealed that the electrode pores contain a considerable number of ions in the absence of an applied charging potential. Experiments and computer simulations have shown that different charging mechanisms can then operate when a potential is applied, going beyond the traditional view of charging by counter-ion adsorption. It is shown that charging almost always involves ion exchange (swapping of co-ions for counter-ions), and rarely occurs by counter-ion adsorption alone. We introduce a charging mechanism parameter that quantifies the mechanism and allows comparisons between different systems. The mechanism is found to depend strongly on the polarization of the electrode, and the choice of the electrolyte and electrode materials. In light of these advances we identify new directions for supercapacitor research. Further experimental and computational work is needed to explain the factors that control supercapacitor charging mechanisms, and to establish the links between mechanisms and performance

  5. DESIGN AND MECHANICAL INTEGRITY OF CO2 INJECTION WELLS

    OpenAIRE

    Nediljka Gaurina-Međimurec; Borivoje Pašić

    2011-01-01

    Geologic Sequestration (GS) is part of a process known as “carbon capture and storage (CCS)” and represents the process of injecting CO2, into deep subsurface rock formations for long-term storage. For injecting of CO2 existing wells are used as well as new drilled wells. A well represents the most likely route for leakage of CO2 from geologic carbon sequestration. Maintaining mechanical integrity helps prevent the well and wellbore from becoming conduits for CO2 migration out of the injectio...

  6. Investigations on Cooling Mechanisms of Highly Charged Ions at HITRAP

    Science.gov (United States)

    Maero, Giancarlo; Herfurth, Frank; Kester, Oliver; Kluge, H.-Jürgen; Koszudowski, Stephen; Quint, Wolfgang; Schwarz, Stefan

    2009-03-01

    The upcoming facility HITRAP (Highly Charged Ion TRAP) at GSI will enable high-precision atomic-physics investigations on heavy, highly charged ions at extremely low energies. Species up to U92+ will be produced at the GSI accelerator complex by stripping of relativistic ions and injected into the Experimental Storage Ring (ESR) where they are electron-cooled and decelerated to 4 MeV/u. After ejection out of the ESR and further deceleration in a linear decelerator bunches of 105 ions will be injected into a Penning trap and cooled to 4 K via electron and resistive cooling. Simulations with a Particle-In-Cell (PIC) code have been carried out to study the dynamics of the ion cloud in the Cooler Trap with focus on resistive cooling in presence of space charge.

  7. Master equation approach to charge injection and transport in organic insulators.

    Science.gov (United States)

    Freire, José A; Voss, Grasiela

    2005-03-22

    We develop a master equation model of a disordered organic insulator sandwiched between metallic electrodes by treating as rate processes both the injection and the internal transport. We show how the master equation model allows for the inclusion of crucial correlation effects in the charge transport, particularly of the Pauli exclusion principle and of space-charge effects, besides, being dependent on just the microscopic form of the transfer rate between the localized electronic states, it allows for the investigation of different microscopic scenarios in the organic, such as polaronic hopping, correlated energy levels, interaction with image charge, etc. The model allows for a separate analysis of the injection and the recombination currents. We find that the disorder, besides increasing the injection current, eliminates the possibility of observation of a Fowler-Nordheim injection current at zero temperature, and that it does not alter the Schottky barrier size of the zero-field thermionic injection current from the value based on the energy difference between the electrode Fermi level and the highest occupied molecular orbital/lowest unoccupied molecular orbital levels in the organic, but it makes the Arrhenius temperature dependence appear at larger temperatures. We investigate how the I(V) characteristics of a device is affected by the presence of correlations in the site energy distribution and by the form of the internal hopping rate, specifically the Miller-Abrahams rate and the Marcus or small-polaron rate. We show that the disorder does not modify significantly the ebeta square root E field dependence of the net current due to the Schottky barrier lowering caused by the attraction between the charge and its image in the electrode. PMID:15836407

  8. Mechanism of Electronic Charging of Coal Mine Dust

    Directory of Open Access Journals (Sweden)

    Cheng Xue-Zhen

    2013-09-01

    Full Text Available The electronic charging of mine dust can cause coal-dust explosion and increase the risk of pneumoconiosis, so it is necessary to take more attention to the study of its electronic charging properties. The mechanism of electronic charging of coal mine dust was investigated in this paper. It was found that the formation and polarity of dust are determined by the energy band structure and of the two contacting sides; then a mathematical model of work function is established in mesoscopic level. The experiments conclude that the work function decreases with the particle size for the dust with same properties, moreover large particles are positively charged and small particles are negatively charged. Finally, the experimental verification of the main particles charged model drive unipolar and bipolar charged modes and confirm the correctness of microstructure and mesoscopic analyses, which furthermore lay the foundation for further research.

  9. Congestion charging mechanisms for roads : an evaluation of current practice

    OpenAIRE

    Hau, Timothy D.

    1992-01-01

    The author explores 20 criteria for a good road pricing system and presents case studies illustrating the costs, revenues, and benefits of alternative congestion charging mechanisms. The author finds that manual tollbooths are not suitable for congestion charging because they are land-, labor-, and time-intensive. Cordon pricing (as in the Bergen toll ring) can be an effective instrument for charging for congestion if half the toll lanes are reserved for seasonal pass holders traveling throug...

  10. Electric Field Analysis of Space Charge Injection from a Conductive Nano-Filler Electrode

    International Nuclear Information System (INIS)

    A simulation on the electric field distribution near the electrode is proposed to explain the reason for using nanosized carbon black mixed with ethylene vinyl acetate, as the electrode could lead to more charge injection into the polymer than using a deposited metal electrode. The electrode is simplified to a layer of conductive semi-spheres with fixed size and constant electric potential. By using the finite element method, it is found that both the size of the semi-spheres and the distance between adjacent semi-spheres could dramatically influence the electric field near the surface of the spheres; these are considered to be the two decisive factors for the charge injecting rate at electrodes of various materials. (condensed matter: electronicstructure, electrical, magnetic, and opticalproperties)

  11. Charge injection and accumulation in organic light-emitting diode with PEDOT:PSS anode

    Energy Technology Data Exchange (ETDEWEB)

    Weis, Martin, E-mail: martin.weis@stuba.sk [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia); Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa, E-mail: iwamoto@ome.pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2015-04-21

    Organic light-emitting diode (OLED) displays using flexible substrates have many attractive features. Since transparent conductive oxides do not fit the requirements of flexible devices, conductive polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been proposed as an alternative. The charge injection and accumulation in OLED devices with PEDOT:PSS anodes are investigated and compared with indium tin oxide anode devices. Higher current density and electroluminescence light intensity are achieved for the OLED device with a PEDOT:PSS anode. The electric field induced second-harmonic generation technique is used for direct observation of temporal evolution of electric fields. It is clearly demonstrated that the improvement in the device performance of the OLED device with a PEDOT:PSS anode is associated with the smooth charge injection and accumulation.

  12. Properties of Laser-Produced Highly Charged Heavy Ions for Direct Injection Scheme

    CERN Document Server

    Sakakibara, Kazuhiko; Hayashizaki, Noriyosu; Ito, Taku; Kashiwagi, Hirotsugu; Okamura, Masahiro

    2005-01-01

    To accelerate highly charged intense ion beam, we have developed the Direct Plasma Injection Scheme (DPIS) with laser ion source. In this scheme an ion beam from a laser ion source is injected directly to a RFQ linac without a low energy beam transport (LEBT) and the beam loss in the LEBT can be avoided. We achieved high current acceleration of carbon ions (60mA) by DPIS with the high current optimized RFQ. As the next setp we will use heavier elements like Ag, Pb, Al and Cu as target in LIS (using CO2, Nd-YAG or other laser) for DPIS and will examine properties of laser-produced plasma (the relationship of between charge state and laser power density, the current dependence of the distance from the target, etc).

  13. Influence of injected charge carriers on photocurrents in polymer solar cells

    OpenAIRE

    Wehenkel, Dominique J.; Koster, L. Jan Anton; Wienk, Martijn M.; Janssen, Rene A. J.

    2012-01-01

    We determine and analyze the photocurrent Jph in polymer solar cells under conditions where, no, one, or two different charge carriers can be injected by choosing appropriate electrodes and compare the experimental results to simulations based on a drift-diffusion device model that accounts for photogeneration and Langevin recombination of electrons and holes. We demonstrate that accounting for the series resistance of the device is essential to determine Jph. Without such correction, the res...

  14. Kinetic treatment of the heavy ion charge exchange injection in synchrotrons

    CERN Document Server

    Dinev, D

    2002-01-01

    This paper describes the results of a kinetic treatment of the charge exchange injection of heavy ions into synchrotrons. Analytical expressions for the evolution of particle density in the transverse phase space and for the emittance growth due to elastic scattering and energy losses in the stripper have been derived. Numerical examples for the superconducting heavy ion synchrotron Nuclotron in JINR-Dubna are given as well.

  15. Simulation on Gas Injection Refining Process with Mechanical Stirring

    Directory of Open Access Journals (Sweden)

    Zhang Ting’an

    2012-12-01

    Full Text Available Basing on the new method of in-situ desulfurization with gas injection and mechanical stirring, the effect of bubble dispersion and disintegration of three type impellers are numerically simulated by commercial CFD software Ansys Fluent 12.0. Numerical simulations of three-dimensional multiphase turbulence in gas injection and mechanical stirring are performed by adopting unsteady SM method coupled with Eulerian multiphase model and two-phase turbulence model. The information of gas-liquid fluid flow, velocity, turbulent kinetic energy and the power consumption are investigated and the results show that the SSB impeller can make bubbles get best dispersion and disintegration,and its power consumption is lower than VB impeller. The disk on the impeller blades can weaken the swirl flow in the upper zone of the impeller. Therefore, the bubble residence time is extended, and the bubble dispersing zone is also increased.

  16. Quality control of injection moulded micro mechanical parts

    DEFF Research Database (Denmark)

    Gasparin, Stefania; Tosello, Guido; Hansen, Hans Nørgaard;

    2009-01-01

    Quality control of micro components is an increasing challenge. Smaller mechanical parts are characterized by smaller tolerance to be verified. This paper focuses on the dimensional verification of micro injection moulded components selected from an industrial application. These parts are measured...... using an Optical Coordinate Measuring Machine (OCMM), which guarantees fast surface scans suitable for in line quality control. The uncertainty assessment of the measurements is calculated following the substitution method. To investigate the influence parameters in optical coordinate metrology two...

  17. Theoretical study on charge injection and transport properties of six emitters with push–pull structure

    International Nuclear Information System (INIS)

    Highlights: • We investigated six small organic molecules by using computational approaches. • This investigation is mainly based on the Marcus electron transfer theory. • The density functional theory (DFT) was used in this investigation. • The IP, EA, reorganization energy and transfer integral were calculated. • We analyzed the charge properties of the molecules by using the computed results. - Abstract: The charge injection and transport properties of six organic light-emitting molecules with push–pull structures were studied by theoretical calculations. The ground-state geometries for the neutral, cationic and anionic states were optimized using density functional theory. Subsequently, the ionization potentials and electron affinities were calculated. We computed the reorganization energies and the transfer integrals based on the Marcus electron transfer theory. It was found that in addition to being emitters the six compounds are multifunctional materials being capable of transport for both holes and electrons. Moreover, the double-branched compound DCDPC2 was found to have higher charge injection ability and better balanced charge transport properties than single-branched compounds

  18. Scanning capacitance microscope study of a SiO2/Si interface modified by charge injection

    Science.gov (United States)

    Tomiye, H.; Yao, T.

    We have investigated the local electrical properties of an SiO2/Si structure using a scanning capacitance microscope (SCaM) combined with an atomic force and a scanning tunneling microscope (AFM and STM). The electrical properties of the Si substrate and the SiO2/Si interface vary with position. In this experiment we have injected charge into the SiO2 and investigated the nature of charge storage at the SiO2/Si interface. We have used the combined microscope to apply a pulse to the SiO2/Si sample, causing charge to be trapped in the SiO2/Si interface. We could clearly detect the local variation of interface charge in a non-destructive manner using the SCaM and simultaneously by capacitance-voltage (C-V) characterization. The volume of the C-V curve shift along the voltage axis due to trapped charges is dependent upon the density of the trapped charges. In doing this experiment we show one of the many possible applications of the combined SCaM/AFM/STM.

  19. Influence of magneto-electric coefficient for magnetic and electric charge injection properties in magneto-electric MIS capacitors

    International Nuclear Information System (INIS)

    We investigated the electric charge injection properties of a floating-gate type metal-insulator Si capacitor having different-ME gate insulators. The samples showed charge-injection type behaviour in capacitance-voltage curves, and it was revealed that the amount of injected charges can be controlled by the application of an external magnetic field. The sample having a high-ME-coefficient gate insulator showed stepwise capacitance-voltage curves unlike the normal one. These results indicate that this capacitor, which employs a magnetic gate insulator, has the potential to be used in multilevel memory by the application of an external magnetic field.

  20. Charge injection properties of iridium oxide films produced on Ti-6Al-4V alloy substrates by ion-beam mixing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.M. (Oak Ridge National Lab., TN (United States)); Lee, I-S.; Buchanan, R.A. (Tennessee Univ., Knoxville, TN (United States))

    1991-10-01

    The charge injection capabilities of iridium oxide films, as produced on Ti6Al-4V alloy substrates by ion beam mixing techniques, have been investigated. Iridium oxide is a valence change oxide, and therefore has high values of charge injection density upon voltage cycling in electrolytes. Because of this property, iridium oxide films are useful as working elements in neural prostheses. Iridium films of three thicknesses, produced by sputter deposition followed by ion beam mixing, were tested in cyclic voltammetry out to 1000 cycles or more. Two surface preparations, mechanical polishing and an acid passivation treatment, were also used as controls. Surface analysis was primarily by Rutherford backscattering spectrometry. Both the ion- beam mixing and the acid pretreatment increased the lifetimes of films, in comparison with the mechanically polished standards. Reductions in charge injection capability, when they occurred, were attributed to loss of Ir from the films, and there was a close correlation between the charge injection density and the Ir inventory. 13 refs., 5 figs.

  1. Effect of main injection timing for controlling the combustion phasing of a homogeneous charge compression ignition engine using a new dual injection strategy

    International Nuclear Information System (INIS)

    Highlights: • A new dual injection concept is developed by minimum geometry modification. • The occurrence of combustion parameters strongly depend on main injection timing. • At higher load, premixed equivalence ratio dominates over main injection timing. • Retarded of main injection timing tends to retard combustion phasing. • Slightly retarded main injection timing is recommended to avoid intense knocking. - Abstract: Homogeneous charge compression ignition combustion of diesel fuel is implemented using a novel dual injection strategy. A new experimental technique is developed to modify a single cylinder direct injection diesel engine to run on homogeneous combustion mode. Effect of main injection timing is investigated covering a range from 26 to 8 crank angle degrees before top dead center with an interval of 3°. Retarded main injection timing is identified as a control strategy for delaying combustion phasing and a means of controlled combustion phasing of direct injection homogeneous charge compression ignition combustion. Two load conditions were investigated and it was observed that at higher load, start of combustion depends more on fuel air equivalence ratio than main injection timing, whereas at low load, it significantly varies with varying main injection timing. Significant improvements in smoke and oxides of nitrogen emissions are observed when compared with the baseline conventional combustion. By studying different combustion parameters, it is observed that there is an improvement in performance and emissions with marginal loss in thermal efficiency when the main injection timing is 20° before top dead center. This is identified as the optimum main injection timing for such homogeneous combustion under the same operating condition

  2. Non-coupled charge explosion and geo-mechanical dynamics

    Institute of Scientific and Technical Information of China (English)

    Zhou Fengjun; Li Xiaojun; Zhou Li; Zheng Lei

    2012-01-01

    The non-coupled charge explosion and geo-mechanical dynamics problem in real air condition is studied in this paper. It analyzes and calculates the problem by using the real air state equations. Through researching on the non- coupled charge rock bench blasting with big clearance of air, its result indicates that the borehole wall reflection over- pressure is far higher than strength of rock, but much lower than detonation front pressure of the charge. So non-coupled charge explosion blasting engineering is very successful. Furthermore, it introduces the method of shaft forming by blas- ting once and the new tube room technology. And the non-coupled charge explosion is used successfully in the method of shaft forming by blasting once. As it drills and blasts in the top and removes the broken rock from the bottom tunnel, it increases the construction efficiency significantly. This paper has important reference on the improvement of the large- span underground engineering construction.

  3. Nonlinear charge transport mechanism in periodic and disordered DNA

    OpenAIRE

    Hennig, Dirk; Archilla, Juan F. R.; J Agarwal

    2003-01-01

    We study a model for polaron-like charge transport mechanism along DNA molecules with emphasis on the impact of parametrical and structural disorder. Our model Hamiltonian takes into account the coupling of the charge carrier to two different kind of modes representing fluctuating twist motions of the base pairs and H-bond distortions within the double helix structure of $\\lambda-$DNA. Localized stationary states are constructed with the help of a nonlinear map approach for a periodic double ...

  4. Beam emittance growth in a proton storage ring employing charge exchange injection

    International Nuclear Information System (INIS)

    Recently, it has been shown that very large currents can be accumulated in medium energy proton storage rings by multiturn injection of an H- beam through a charge stripping medium. Since the particles are injected continuously into the same phase space, it is possible to increase the circulating beam brightness with respect to that of the incoming beam by a large factor. The stored protons pass repeatedly through the stripper, however, so that this phase space is gradually enlarged by scattering. The dependence of the circulating beam phase space (emittance) growth rate on the nature of the scattering process and on where it occurs in the storage ring matrix is considered. Since the motivation for this work arose in connection with the design of the proposed high-current storage ring at LAMPF, the results are focused on the specific parameters of that device. (U.S.)

  5. Calibration by precise charge injection of a sub-detector of CMS; Calibration par injection de charge du calorimetre electromagnetique de CMS

    Energy Technology Data Exchange (ETDEWEB)

    Yong-Wook Baek

    2001-01-26

    This thesis was carried out within the framework of the international collaboration which has the responsibility of the experience CMS (Compact Muon Solenoid) on LHC, at CERN. The physics of the fundamental particles which will be explored by this experiment is described within the standard model. The configuration of sub-detector of CMS is briefly described, with a particular weight on the read-out chain of the electromagnetic calorimeter. The work carried out to calibrate this chain by a precise charge injection at the input of preamplifiers is described. The 4 integrated circuits CTRL, TPLS, DAC, and injector which will constitute the components of this chain of calibration are described. The circuit of injection, which is the main circuit in this project, was imagined and developed at the laboratory in DMILL technology. This injector generates a signal which has a form identical to the signal of the detector. The measurements on the linearity of the injectors are presented. In order to know its behavior under real conditions (flow of neutrons {approx} 2 x 10{sup 13} neutrons/cm{sup 2}/10 years) where this circuit is installed in detector CMS, we submitted the prototypes of injector to irradiation and the results are summarized. The research and development on this circuit produced an integrated circuit hardened to irradiations, whose variation of slope is lower than 0.25% for an integrated of 2 x 10{sup 13} neutrons/cm{sup 2} and indestructible under 10{sup 15} neutrons/cm{sup 2}. This circuit has satisfactory qualities to be assembled on the electronic card which will treat the data of calorimeter ECAL of CMS. (author)

  6. An advanced tracker design for pointing and control of space vehicles using the charge injection device

    Science.gov (United States)

    Jones, C.; Kollodge, J. C.

    1982-01-01

    The use of charge transfer devices (CTD) in pointing and control of space vehicles is examined, with emphasis on the use of charge injection devices (CID). The selection of CTD type and CID operation, including CID signal and noise analysis and signal improvement, are discussed. Star tracking operational advantages of the CTD are pointed out, and the tracking optical concept is discussed and graphically depicted. The position interpolation procedure and the effects of rate of stellar motion on position interpolation are considered, and error analysis is examined. Finally, the breadboard and test program are discussed in detail, coarse and fine acquisition, test for star, track pattern, test procedure and results. An overall accuracy performance of approximately 0.02 pixels or approximately 0.8 arcsec for the test equipment and tracker was obtained.

  7. Testing double ionization mechanisms with highly-charged ions

    International Nuclear Information System (INIS)

    Double ionization of He target atoms by intermediate- to high-velocity charged ions is considered in terms of two mechanisms: (1) a two-step (TS) process in which both target electrons are removed in separate direct interactions with the projectile, and (2) a one-step mechanism in which one electron is liberated in a single projectile-target interaction followed by subsequent ''shakeoff'' (SO) of the second electron. Measured double-to-single ionization ratios are used to exhibit and test the underlying mechanisms of double ionization. It is found that these ratios exhibit a high degree of universality as a function of v/q, where v is the velocity of the ion and q is its charge. The results strongly suggest that the important factor in determining the regions of validity for TS and SO is the ionic charge divided by the impact velocity and not just the impact velocity itself

  8. ReO{sub x} charge injection/blocking layers in organic electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Luo Jiaxiu; Xiao Lixin; Chen Zhijian; Qu Bo; Gong Qihuang, E-mail: xiao66@pku.edu.c, E-mail: qhgong@pku.edu.c [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China)

    2010-09-29

    The charge transport of rhenium oxide (ReO{sub x}) in organic electronic devices was investigated. The hole injection/transport was blocked and the electron injection/transport was enhanced with doping of ReO{sub x} in organic electronic devices. Thus the charge balance and efficiency of organic light-emitting diodes were improved; current efficiency of 2.7 cd A{sup -1} at 20 mA cm{sup -2} for the device with ReO{sub x} was higher than 1.5 cd A{sup -1} for the device without it. In the case of organic photovoltaic cells, the open-circuit voltage (V{sub oc}), 0.58 V, was higher compared with the device without ReO{sub x} (0.44 V) due to the improvement of interface properties. The power conversion efficiency was increased to 2.27% by the combination of ReO{sub x} (increases V{sub oc}) with poly(3,4-ethylenedioxythiophene) : poly(styrene-sulfonate) (improves hole transport to increase J{sub sc}) on the modification of the anode, higher than 1.85% for the device without ReO{sub x}.

  9. Construction of a Direct Water-Injected Two-Stroke Engine for Phased Direct Fuel Injection-High Pressure Charging Investigations

    Science.gov (United States)

    Somsel, James P.

    1998-01-01

    The development of a water injected Orbital Combustion Process (OCP) engine was conducted to assess the viability of using the powerplant for high altitude NASA aircraft and General Aviation (GA) applications. An OCP direct fuel injected, 1.2 liter, three cylinder, two-stroke engine has been enhanced to independently inject water directly into the combustion chamber. The engine currently demonstrates low brake specific fuel consumption capability and an excellent power to weight ratio. With direct water injection, significant improvements can be made to engine power, to knock limits/ignition advance timing, and to engine NO(x) emissions. The principal aim of the testing was to validate a cyclic model developed by the Systems Analysis Branch at NASA Ames Research Center. The work is a continuation of Ames' investigations into a Phased Direct Fuel Injection Engine with High Pressure Charging (PDFI-ITPC).

  10. Dimensional changes as a function of charge injection for trans-polyacetylene: A density functional theory study

    Science.gov (United States)

    Sun, Guangyu; Kurti, Jeno; Kertesz, Miklos; Baughman, Ray H.

    2002-10-01

    Charge-induced dimensional changes allow conducting polymers and single walled carbon nanotubes to function as electromechanical actuators. The unit cell of the prototypical conducting polymer, trans-polyacetylene, was calculated as a function of charge injection using density functional theory in combination with ultrasoft pseudopotentials using the solid-state Vienna ab initio simulation package. Test calculations on the charged pyridinium molecular ion give results in good agreement with the experimental geometry. Strain versus charge relationships are predicted from dimensional changes calculated using a uniform background charge ("jellium") for representing the counterions, which we show provides results consistent with experiment for doped polyacetylenes. These jellium calculations are consistent with further presented calculations that include specific counterions, showing that hybridization between the guest dopant ions and the host polyacetylene chains is unimportant. The lack of guest-host orbital hybridization allows a qualitative rigid band interpretation of the amount of charge transfer for both acceptor and donor doping. For polyacetylene, asymmetry of strain along the chain with respect to the sign of the charge is predicted: negative charge elongates and positive charge shortens the polymer. For charge less than 0.05e per carbon, an approximately linear dependence is obtained for the dependence of chain-direction strain on the amount of injected charge.

  11. Controlled Electron Injection into Plasma Accelerators and SpaceCharge Estimates

    Energy Technology Data Exchange (ETDEWEB)

    Fubiani, Gwenael J.

    2005-09-01

    Plasma based accelerators are capable of producing electron sources which are ultra-compact (a few microns) and high energies (up to hundreds of MeVs) in much shorter distances than conventional accelerators. This is due to the large longitudinal electric field that can be excited without the limitation of breakdown as in RF structures.The characteristic scale length of the accelerating field is the plasma wavelength and for typical densities ranging from 1018 - 1019 cm-3, the accelerating fields and scale length can hence be on the order of 10-100GV/m and 10-40 mu m, respectively. The production of quasimonoenergetic beams was recently obtained in a regime relying on self-trapping of background plasma electrons, using a single laser pulse for wakefield generation. In this dissertation, we study the controlled injection via the beating of two lasers (the pump laser pulse creating the plasma wave and a second beam being propagated in opposite direction) which induce a localized injection of background plasma electrons. The aim of this dissertation is to describe in detail the physics of optical injection using two lasers, the characteristics of the electron beams produced (the micrometer scale plasma wavelength can result in femtosecond and even attosecond bunches) as well as a concise estimate of the effects of space charge on the dynamics of an ultra-dense electron bunch with a large energy spread.

  12. Mechanisms of Particle Charging by Surfactants in Nonpolar Dispersions.

    Science.gov (United States)

    Lee, Joohyung; Zhou, Zhang-Lin; Alas, Guillermo; Behrens, Sven Holger

    2015-11-10

    Electric charging of colloidal particles in nonpolar solvents plays a crucial role for many industrial applications and products, including rubbers, engine oils, toners, or electronic displays. Although disfavored by the low solvent permittivity, particle charging can be induced by added surfactants, even nonionic ones, but the underlying mechanism is poorly understood, and neither the magnitude nor the sign of charge can generally be predicted from the particle and surfactant properties. The conclusiveness of scientific studies has been limited partly by a traditional focus on few surfactant types with many differences in their chemical structure and often poorly defined composition. Here we investigate the surface charging of poly(methyl methacrylate) particles dispersed in hexane-based solutions of three purified polyisobutylene succinimide polyamine surfactants with "subtle" structural variations. We precisely vary the surfactant chemistry by replacing only a single electronegative atom located at a fixed position within the polar headgroup. Electrophoresis reveals that these small differences between the surfactants lead to qualitatively different particle charging. In the respective particle-free surfactant solutions we also find potentially telling differences in the size of the surfactant aggregates (inverse micelles), the residual water content, and the electric solution conductivity as well as indications for a significant size difference between oppositely charged inverse micelles of the most hygroscopic surfactant. An analysis that accounts for the acid/base properties of all constituents suggests that the observed particle charging is better described by asymmetric adsorption of charged inverse micelles from the liquid bulk than by charge creation at the particle surface. Intramicellar acid-base interaction and intermicellar surfactant exchange help rationalize the formation of micellar ions pairs with size asymmetry. PMID:26484617

  13. Approaching charge balance in organic light-emitting diodes by tuning charge injection barriers with mixed monolayers.

    Science.gov (United States)

    Yu, Szu-Yen; Huang, Ding-Chi; Chen, Yi-Ling; Wu, Kun-Yang; Tao, Yu-Tai

    2012-01-10

    Self-assembled monolayers (SAMs) of binary mixtures of 1-butylphosphonic acid and the trifluoromethyl-terminated analogue (4,4,4-trifluoro-1-butylphosphonic acid) were formed on ITO surfaces to tune the work function of ITO over a range of 5.0 to 5.75 eV by varying the mixing ratio of the two adsorbents. The mixed SAM-modified ITO surfaces were used as the anode in the fabrication of OLED devices with a configuration of ITO/SAM/HTL/Alq3/MX/Al, where HTL was the NPB or BPAPF hole-transporting layer and MX was the LiF or Cs(2)CO(3) injection layer. It was shown that, depending on the HTL or MX used, the maximum device current and the maximum luminance efficiency occurred with anodes of different modifications because of a shift in the point of hole/electron carrier balance. This provides information on the charge balance in the device and points to the direction to improve the performance. PMID:22103763

  14. Laser photoionization of H0 beams for charge-changing injection

    International Nuclear Information System (INIS)

    The two-step charge-changing injection used in the Los Alamos Proton Storage Ring (PSR) requires stripping of H- to H0 by high magnetic fields and subsequent stripping of H0 to H+ by a carbon foil. The authors consider single- and multiphoton laser ionization as alternatives to using a fragile foil. The multiphoton case is of possible interest for selection of practical lasers, which tend to have increased power output at higher wavelengths. The formulas derived express the necessary laser powers for ionization of monoenergetic H0 beams; they also hold for beams of particles other than atomic hydrogen. The numerical examples given are for the 800-MeV PSR beam with momentum spread taken into account. Additionally, they discuss selective stripping as an implication of the inherent energy selectivity of the photoionization process

  15. Laser photoionization of H0 beams for charge-changing injection

    International Nuclear Information System (INIS)

    The two-step charge-changing injection used in the Los Alamos Proton Storage Ring (PSR) requires stripping of H- to H0 by high magnetic fields and subsequent stripping of H0 to H+ by a carbon foil. We consider single- and multiphoton laser ionization as alternatives to using a fragile foil. The multiphoton case is of possible interest for selection of practical lasers, which tend to have increased power output at higher wavelengths. The formulas derived express the necessary laser powers for ionization of monoenergetic H0 beams; they also hold for beams of particles other than atomic hydrogen. The numerical examples given are for the 800-MeV PSR beam with momentum spread taken into account. Additionally, we discuss selective stripping as an implication of the inherent energy selectivity of the photoionization process

  16. Organic integrated circuits for information storage based on ambipolar polymers and charge injection engineering

    International Nuclear Information System (INIS)

    Ambipolar semiconducting polymers, characterized by both high electron (μe) and hole (μh) mobility, offer the advantage of realizing complex complementary electronic circuits with a single semiconducting layer, deposited by simple coating techniques. However, to achieve complementarity, one of the two conduction paths in transistors has to be suppressed, resulting in unipolar devices. Here, we adopt charge injection engineering through a specific interlayer in order to tune injection into frontier energy orbitals of a high mobility donor-acceptor co-polymer. Starting from field-effect transistors with Au contacts, showing a p-type unbalanced behaviour with μh = 0.29 cm2/V s and μe = 0.001 cm2/V s, through the insertion of a caesium salt interlayer with optimized thickness, we obtain an n-type unbalanced transistor with μe = 0.12 cm2/V s and μh = 8 × 10−4 cm2/V s. We applied this result to the development of the basic pass-transistor logic building blocks such as inverters, with high gain and good noise margin, and transmission-gates. In addition, we developed and characterized information storage circuits like D-Latches and D-Flip-Flops consisting of 16 transistors, demonstrating both their static and dynamic performances and thus the suitability of this technology for more complex circuits such as display addressing logic

  17. Characteristics of the injected ion beam in the ECR charge breeder 1+ -> n+

    CERN Document Server

    Lamy, T; Chauvin, N; Curdy, Jean Claude; Geller, R; Sortais, P; Leroy, R; Lieuvin, M; Villari, A C C

    1999-01-01

    Different ion species (rare gases, alkali, metallic) have been injected on the axis of the MINIMAFIOS - 10 GHz - Electron Cyclotron Resonance Ion Source which is the basics of the 1+ -> n+ method, special attention have been paid to the optics of the incoming beam for the validation of the 1+ -> n+ method for the SPIRAL project (Radioactive Ion Beam facility). The capture of the incoming ion beam by the ECR plasma depends, first, on the relative energy of the incoming ions with respect to the average ion energy in the plasma, and secondly, on the optics of the injection line. The efficiency of the process when varying the potential V n+ of the MINIMAFIOS source with respect to the potential V 1+ applied to the 1+ source (DV=V n+ -V 1+ ) is an image of the energy dispersion of the 1+ beam. 1+ -> n+ spectra efficiencies, DV efficiency dependence for the most efficient charge state obtained, and measured primary beam emittances are given for the Ar, Rb, Pb, Cr. Highest efficiencies obtained are respectively Ar1+...

  18. Controlling charge carrier injection in organic electroluminescent devices via ITO substrate modification

    CERN Document Server

    Day, S

    2001-01-01

    and the ITO substrate was found to shift the work function of the electrode, and so modify the barrier to hole injection. Scanning Kelvin probe measurements show that the ITO work function is increased by 0.25 eV with a film of TNAP, while a C sub 6 sub 0 film is found to reduce the work function by a comparable amount. The former has been attributed to a charge-transfer effect resulting in Fermi level alignment between the ITO and the TNAP layer, however the latter is believed to result from both charge transfer and a covalent interaction between C sub 6 sub 0 and ITO. The performance of devices incorporating these modified ITO electrode are rationalised in terms of the work function modification, film thicknesses and the hole transport properties of the two films. Competition between the induced work function change and the increasingly significant tunnelling barrier with thickness means that device performance is not as good as that provided by the SAMs. Direct processing of the ITO substrate has also been...

  19. Providing Authentication & Authorization Mechanisms for Active Service Charging

    OpenAIRE

    Bagnulo, Marcelo; Alarcos, Bernardo; Calderón, María; Marifeli, Sedano

    2002-01-01

    Active network technology enables fast deployment of new network services tailored to the specific needs of end users, among others features. Nevertheless proper charging for these new added value services require suitable authentication and authorization mechanisms. In this article we describe a security architecture for SARA (Simple Active Router-Assistant) architecture, an active network platform deployed in the context of the IST-GCAP project. The proposed solution provides all the requir...

  20. Relation between microstructure and dielectric breakdown in the case of aluminous ceramics (SEMM method); Comportement d'alumines face a l'injection de charges. Relation microstructure - claquage dielectrique - mesure des charges d'influence (methode SEMM)

    Energy Technology Data Exchange (ETDEWEB)

    Liebault, J.

    1999-02-01

    The dielectric breakdown is strongly linked to the injection and the accumulation of charges in a non-conducting material. The physics of charged insulators proposes mechanisms of trapping and transport of charges in aluminium oxides by considering defects as localization sources of charges and of energy. In order to measure the influence of defects on dielectric breakdown, various aluminous ceramics have been elaborated. The nature and the quantity of defects have been characterized by the nature and the rate of impurities, by porosity, by the quantity of grain boundaries and by the presence and distribution of secondary phases. These materials have undergone breakdown tests. The dielectric rigidity depends strongly on the nature and the distribution of crystallographic defects (vacancy, interstitial ions and dislocation), on the other hand porosity below 5% has no influence. The doping of an alumina ceramic containing less than 100 ppm of impurities implies a diminution of its dielectric rigidity. The measurement of the SEMM (scanning electron microscopy mirror) effect allows the characterization of insulating materials. This method permits the evaluation of the ability for materials to trap charges, it gives information about the charge kinetic of trapping, charge localization and the energy levels of traps. (A.C.)

  1. Femtosecond insights into direct electron injection in dye anchored ZnO QDs following charge transfer excitation.

    Science.gov (United States)

    Kumar, Pushpendra; Kumar, Sunil; Ghosh, Subrata; Pal, Suman Kalyan

    2016-07-27

    The role of the charge transfer (CT) state in interfacial electron transfer in dye-sensitized semiconductor nanocrystals is still poorly understood. To address this problem, femtosecond transient absorption (TA) spectroscopy is used as a probe to investigate the electron injection across a newly synthesized coumarin dye (8-hydroxy-2-oxo-4-phenyl-2 benzo[h]chromene-3-carbonitrile, coded BC5) and ZnO quantum dots (QDs). Steady state and time-resolved spectroscopic measurements reveal that BC5 dye interacts strongly with ZnO QDs in the ground state forming a CT complex. The BC5-ZnO QD complex absorbs more towards red compared to only the dye and QDs, and emits fluorescence due to radiative recombination of photogenerated charges. The formation of charges following the excitation of the CT complex has been demonstrated by observing the signature of dye radical cations and electrons in the conduction band (CB) of the QDs in the TA spectra. The TA signals of these charges grow sharply as a result of ultrafast direct electron injection into the QD. We have monitored the complete dynamics of photogenerated charges by measuring the TA signals of the charges up to a couple of nanoseconds. The injected electrons that are free or shallowly trapped recombine with a time constant of 625 fs, whereas deeply trapped electrons disappear slowly (526 ps) via radiative recombination. Furthermore, theoretical studies based on ab initio calculations have been carried out to complement the experimental findings. PMID:27412034

  2. Charge exchange as a recombination mechanism in high-temperature plasmas

    International Nuclear Information System (INIS)

    Charge exchange with neutral hydrogen is examined as a recombination mechanism for multi-charged impurity ions present in high-temperature fusion plasmas. At sufficiently low electron densities, fluxes of atomic hydrogen produced by either the injection of neutral heating beams or the background of thermal neutrals can yield an important or even dominant recombination process for such ions. Equilibrium results are given for selected impurity elements showing the altered ionization balance and radiative cooling rate produced by the presence of various neutral populations. A notable result is that the stripping of impurities to relatively non-radiative ionization states with increasing electron temperature can be postponed or entirely prevented by the application of intense neutral beam heating power. A time dependent calculation modelling the behavior of iron in recent PLT tokamak high power neutral beam heating experiments is also presented

  3. Balanced charge injection in multilayer polymer light-emitting diode with water soluble nonconjugated polymer dispersed by ionic compounds

    Science.gov (United States)

    Park, Dong-Kyu; Chun, A.-Rum; Kim, Soo-Hong; Kim, Min-Sook; Kim, Choong-Gi; Kwon, Tae-Woo; Cho, Seong-Jin; Woo, Hyung-Suk; Lee, Jae-Gyoung; Lee, Suck-Hyun; Guo, Zhi-Xin

    2007-07-01

    The authors have fabricated highly efficient polymeric light-emitting diode (PLED) from ionic compound dispersed water soluble nonconjugated polymer, polyurethane (PU), which was used as an ultrathin hole blocking and electron injection layer (HB-EIL) on the top of commercially available blue-emitting polymer, polyfluorene. The device with HB-EIL showed a maximum quantum efficiency of 1.7%, while the one without HB-EIL showed an efficiency of 0.6%. They propose that the better performance in PLED with PU layer was due to a well balanced charge injection in emitting layer after the enhanced electron injection due to ionic compound in the insulating PU layer.

  4. Excitation of HF and ULF-VLF waves during charged particle beams injection in active space experiment

    International Nuclear Information System (INIS)

    Results of active space experiment with simultaneous injection of electron and xenon ion beams from the Interkosmos-25 (IK-25) satellite are presented. A specific feature of this experiment was that charged particles were injected in the same direction along the magnetic field lines and the particle beams simultaneously injected into the ionospheric plasma were therefore nested in one another. Results of the beam-plasma interaction for this configuration were registered by the double satellite system consisting of IK-25 station and Magion-3 subsatellite. (author)

  5. ACTIVE LONGITUDINAL PAINTING FOR THE H-CHARGE EXCHANGE INJECTION OF THE LINAC4 BEAM INTO THE PS BOOSTER

    CERN Document Server

    CARLI, C; CERN. Geneva. AB Department

    2008-01-01

    Linac4 will provide 160 MeV H- to the PS Booster synchrotron. The H-beam will be injected by charge exchange injection allowing injecting several times into the same volumes of phase space. Thus, a large number of turns can be injected with high efficiencies and â€ワpainting” in order to shape the initial particle distribution for optimum performance becomes possible. In particular, a chopper makes longitudinal painting possible in addition to painting in transverse phase spaces. The slow synchrotron motion in the PS Booster implies an active longitudinal painting scheme, where the Linac4 output energy is modulated. Several active longitudinal painting schemes are presented. One scheme, based on a triangular Linac energy modulation, is proposed for the PS Booster H- injection with Linac4.

  6. Numerical simulation on the mechanism of the dynamic injection for low permeable rock masses

    International Nuclear Information System (INIS)

    Dynamic injection is a technique for grout injection by oscillating pressure added to a fixed underlying pressure. This technique is efficient to inject grouting material into micro-fractures in low permeable rock masses. In this study, the author proposes the numerical model of cement penetration process using Distinct Element Method (DEM) and carries out numerical simulations in order to clarify the mechanism of grout penetration by dynamic injection. (author)

  7. Organic integrated circuits for information storage based on ambipolar polymers and charge injection engineering

    Energy Technology Data Exchange (ETDEWEB)

    Dell' Erba, Giorgio; Natali, Dario [Center for Nano Science and Technology PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy); Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano (Italy); Luzio, Alessandro; Caironi, Mario, E-mail: mario.caironi@iit.it, E-mail: yynoh@dongguk.edu [Center for Nano Science and Technology PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano (Italy); Kim, Juhwan; Khim, Dongyoon; Kim, Dong-Yu [Heeger Center for Advanced Materials, School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of); Noh, Yong-Young, E-mail: mario.caironi@iit.it, E-mail: yynoh@dongguk.edu [Department of Energy and Materials Engineering, Dongguk University, 26 Pil-dong, 3-ga, Jung-gu, Seoul 100-715 (Korea, Republic of)

    2014-04-14

    Ambipolar semiconducting polymers, characterized by both high electron (μ{sub e}) and hole (μ{sub h}) mobility, offer the advantage of realizing complex complementary electronic circuits with a single semiconducting layer, deposited by simple coating techniques. However, to achieve complementarity, one of the two conduction paths in transistors has to be suppressed, resulting in unipolar devices. Here, we adopt charge injection engineering through a specific interlayer in order to tune injection into frontier energy orbitals of a high mobility donor-acceptor co-polymer. Starting from field-effect transistors with Au contacts, showing a p-type unbalanced behaviour with μ{sub h} = 0.29 cm{sup 2}/V s and μ{sub e} = 0.001 cm{sup 2}/V s, through the insertion of a caesium salt interlayer with optimized thickness, we obtain an n-type unbalanced transistor with μ{sub e} = 0.12 cm{sup 2}/V s and μ{sub h} = 8 × 10{sup −4} cm{sup 2}/V s. We applied this result to the development of the basic pass-transistor logic building blocks such as inverters, with high gain and good noise margin, and transmission-gates. In addition, we developed and characterized information storage circuits like D-Latches and D-Flip-Flops consisting of 16 transistors, demonstrating both their static and dynamic performances and thus the suitability of this technology for more complex circuits such as display addressing logic.

  8. Calibration by precise charge injection of a sub-detector of CMS

    International Nuclear Information System (INIS)

    This thesis was carried out within the framework of the international collaboration which has the responsibility of the experience CMS (Compact Muon Solenoid) on LHC, at CERN. The physics of the fundamental particles which will be explored by this experiment is described within the standard model. The configuration of sub-detector of CMS is briefly described, with a particular weight on the read-out chain of the electromagnetic calorimeter. The work carried out to calibrate this chain by a precise charge injection at the input of preamplifiers is described. The 4 integrated circuits CTRL, TPLS, DAC, and injector which will constitute the components of this chain of calibration are described. The circuit of injection, which is the main circuit in this project, was imagined and developed at the laboratory in DMILL technology. This injector generates a signal which has a form identical to the signal of the detector. The measurements on the linearity of the injectors are presented. In order to know its behavior under real conditions (flow of neutrons ∼ 2 x 1013 neutrons/cm2/10 years) where this circuit is installed in detector CMS, we submitted the prototypes of injector to irradiation and the results are summarized. The research and development on this circuit produced an integrated circuit hardened to irradiations, whose variation of slope is lower than 0.25% for an integrated of 2 x 1013 neutrons/cm2 and indestructible under 1015 neutrons/cm2. This circuit has satisfactory qualities to be assembled on the electronic card which will treat the data of calorimeter ECAL of CMS. (author)

  9. The stability mechanisms of an injectable calcium phosphate ceramic suspension.

    OpenAIRE

    Fatimi, Ahmed; Tassin, Jean-François; Axelos, Monique; Weiss, Pierre

    2010-01-01

    Calcium phosphate ceramics are widely used as bone substitutes in dentistry and orthopedic applications. For minimally invasive surgery an injectable calcium phosphate ceramic suspension (ICPCS) was developed. It consists in a biopolymer (hydroxypropylmethylcellulose: HPMC) as matrix and bioactive calcium phosphate ceramics (biphasic calcium phosphate: BCP) as fillers. The stability of the suspension is essential to this generation of "ready to use" injectable biomaterial. But, during storage...

  10. Extreme Contrast Ratio Imaging of Sirius with a Charge Injection Device

    CERN Document Server

    Batcheldor, D; Bahr, C; Jenne, J; Ninkov, Z; Bhaskaran, S; Chapman, T

    2015-01-01

    The next fundamental steps forward in understanding our place in the universe could be a result of advances in extreme contrast ratio (ECR) imaging and point spread function (PSF) suppression. For example, blinded by quasar light we have yet to fully understand the processes of galaxy formation and evolution, and there is an ongoing race to obtain a direct image of an exoearth lost in the glare of its host star. To fully explore the features of these systems we must perform observations in which contrast ratios of at least one billion can be regularly achieved with sub 0.1" inner working angles. Here we present the details of a latest generation 32-bit charge injection device (CID) that could conceivably achieve contrast ratios on the order of one billion. We also demonstrate some of its ECR imaging abilities for astronomical imaging. At a separation of two arc minutes, we report a direct contrast ratio of Delta(m_v)=18.3, log(CR)=7.3, or 1 part in 20 million, from observations of the Sirius field. The atmosp...

  11. LDV measurements of liquid velocity induced by charge injection in Diesel oil in a blade-plane-slit geometry

    Energy Technology Data Exchange (ETDEWEB)

    Daaboul, Michel; Louste, Christophe; Romat, Hubert [Laboratoire d' Etudes Aerodynamiques - Universite de Poitiers, ENSMA, CNRS SP2MI - Teleport 2 - Boulevard Pierre et Marie Curie - BP 30179 86962 Futuroscope Chasseneuil Cedex (France)], E-mail: michel.daaboul@lea.univ.poitiers.fr, E-mail: christophe.louste@lea.univ-poitiers.fr, E-mail: hubert.romat@lea.univ-poitiers.fr

    2008-12-01

    When applying a high potential to a blade or a pin immerged in an insulating liquid, ions are injected from the electrodes into the liquid. Several researches have been made on blade-plane geometry and important results have been already issued. In this paper, we test a blade-plane geometry with a two-plate system creating a slit in front of the blade and for which the fluid flow produced by the injected ions is modified by the slit. The electric current is also different from the one obtained with a simple blade-plane geometry. We first present the evolution of the injected current as a function of the applied voltage. Then we study the characteristics of the injection of charges and particularly the threshold of both voltage and electric field. We finally present a Laser Doppler Velocimetry (LDV) study of the flow.

  12. LDV measurements of liquid velocity induced by charge injection in Diesel oil in a blade-plane-slit geometry

    International Nuclear Information System (INIS)

    When applying a high potential to a blade or a pin immerged in an insulating liquid, ions are injected from the electrodes into the liquid. Several researches have been made on blade-plane geometry and important results have been already issued. In this paper, we test a blade-plane geometry with a two-plate system creating a slit in front of the blade and for which the fluid flow produced by the injected ions is modified by the slit. The electric current is also different from the one obtained with a simple blade-plane geometry. We first present the evolution of the injected current as a function of the applied voltage. Then we study the characteristics of the injection of charges and particularly the threshold of both voltage and electric field. We finally present a Laser Doppler Velocimetry (LDV) study of the flow.

  13. Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

    Directory of Open Access Journals (Sweden)

    Jacek Hunicz

    2015-01-01

    Full Text Available In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

  14. In situ measurement of plasma charging on SiO2 hole bottoms and reduction by negative charge injection during etching

    International Nuclear Information System (INIS)

    Charging damage in the fabrication of a micro- and nanoelectronic device is one of the electrical damages during plasma etching and caused basically by a huge difference of the flux velocity distribution between positive ions and electrons toward the wafer to be processed. Beam-like positive ions are accumulated on the bottom of a miniaturized structure during etching. With the evolution of the technology node, charging damage will increase due to several factors, increase of plasma exposure time, decrease of annealing temperature, and narrow process window, etc., caused by the increase of the number of metal layers and the introduction of new materials such as low-k and high-k instead of SiO2. The progress of a top-down nanotechnology depends on the development of in situ diagnostics regarding plasma damage to lower-level elements and on the development of charging-free plasma process. In this paper, in situ charging measurements by using a test chip and negative charge injection to the wafer by optical computerized tomography are first demonstrated. Second, we discuss the characteristics of the charging potential on the bottom of SiO2holes during etching in a two-frequency capacitively coupled plasma (2f-CCP), and refer to the procedure to reduce the positive potential by utilizing the negative charge acceleration to the hole bottom under the artificial formation of a double-layer close to the wafer. In addition, the charging's effect on the aspect ratio of the hole and the antenna ratio are discussed

  15. Extreme Contrast Ratio Imaging of Sirius with a Charge Injection Device

    Science.gov (United States)

    Batcheldor, D.; Foadi, R.; Bahr, C.; Jenne, J.; Ninkov, Z.; Bhaskaran, S.; Chapman, T.

    2016-02-01

    The next fundamental steps forward in understanding our place in the universe could be a result of advances in extreme contrast ratio (ECR) imaging and point-spread function (PSF) suppression. For example, blinded by quasar light we have yet to fully understand the processes of galaxy and star formation and evolution, and there is an ongoing race to obtain a direct image of an exo-Earth lost in the glare of its host star. To fully explore the features of these systems, we must perform observations in which contrast ratios (CRs) of at least one billion can be regularly achieved with sub 0.″1 inner working angles. Here, we present the details of a latest-generation 32-bit charge injection device (CID) that could conceivably achieve CRs on the order of one billion. We also demonstrate some of its ECR imaging abilities for astronomical imaging. At a separation of two arcminutes, we report a direct CR of {{Δ }}{m}v=18.3,{log}({CR})=7.3, or 1 part in 20 million, from observations of the Sirius field. The atmospheric conditions present during the collection of this data prevented less modest results, and we expect to be able to achieve higher CRs, with improved inner working angles, simply by operating a CID at a world-class observing site. However, CIDs do not directly provide any PSF suppression. Therefore, combining CID imaging with a simple PSF suppression technique like angular differential imaging could provide a cheap and easy alternative to the complex ECR techniques currently being employed.

  16. An experimental technique for the study of non-avalanche charge injection or trapping in MIS structures

    Science.gov (United States)

    Kolk, J.; Heasell, E.

    1980-03-01

    In the study of charge injection in the insulator-silicon system, variation of the electric field in the insulator, caused by charge trapping during a measurement, makes the interpretation and analysis of experimental data difficult. A measuring system and test device structure are described in which it is possible to monitor any change of the device threshold voltage and to adjust the applied gate voltage so as to maintain a constant electric field at the insulator-silicon interface. Experimental results will be presented which show the advantages stemming from this mode of operation.

  17. Injection-Molded Soft Magnets Prepared from Fe-Based Metallic Glass: Mechanical and Magnetic Properties

    Science.gov (United States)

    Zhong, Tian; Huang, Ran; Huang, Jia; Ouyang, Wei

    2015-10-01

    The injection-molded metallic glass soft magnet is prepared from the powder of melt-spun ribbon of Fe36Co36B20Si4Nb4 glassy alloy and Nylon 6,6 of wt.% from 5 to 20 via the polymer injection molding technology. The product is characterized by the SEM, mechanical, and magnetic test. The results indicate that this type of materials has comparable mechanical properties and morphological feature with the conventional injection-molded NdFeB magnet and exhibits excellent soft magnetic behaviors. The magnetic properties of the injected magnets are compared with the raw metallic glass, solvent-casted resin bonding magnets, and thermal-treated magnets to confirm that the processing temperature of Nylon injection does not affect the magnetism. The injection technology is a practical processing method to be applied on the metallic glass for potential usage.

  18. Flexible charge balanced stimulator with 5.6 fC accuracy for 140 nC injections.

    Science.gov (United States)

    Nag, Sudip; Jia, Xiaofeng; Thakor, Nitish V; Sharma, Dinesh

    2013-06-01

    Electrical stimulations of neuronal structures must ensure net injected charges to be zero for biological safety and voltage compliance reasons. We present a novel architecture of general purpose biphasic constant current stimulator that exhibits less than 5.6 fC error while injecting 140 nC charges using 1.4 mA currents. The floating current sources and conveyor switch based system can operate in monopolar or bipolar modes. Anodic-first or cathodic-first pulses with optional inter-phase delays have been demonstrated with zero quiescent current requirements at the analog front-end. The architecture eliminates blocking capacitors, electrode shorting and complex feedbacks. Bench-top and in-vivo measurement results have been presented with emulated electrode impedances (resistor-capacitor network), Ag-AgCl electrodes in saline and in-vivo (acute) peripheral nerve stimulations in anesthetized rats. PMID:23853326

  19. Unipolar and bipolar fatigue in antiferroelectric lead zirconate thin films and evidences for switching-induced charge injection inducing fatigue

    OpenAIRE

    Lou, X. J.; Wang, J.

    2010-01-01

    For the first time, we show that unipolar fatigue does occur in antiferroelectric capacitors, confirming the predictions of a previous work [Appl. Phys. Lett., 94, 072901 (2009)]. We also show that unipolar fatigue in antiferroelectrics is less severe than bipolar fatigue if the driving field is of the same magnitude. This phenomenon has been attributed to the switching-induced charge injection, the main cause for polarization fatigue in ferroelectric and antiferroelectric materials. Other ev...

  20. Focused fault injection testing of software implemented fault tolerance mechanisms of Voltan TMR nodes

    Science.gov (United States)

    Tao, S.; Ezhilchelvan, P. D.; Shrivastava, S. K.

    1995-03-01

    One way of gaining confidence in the adequacy of fault tolerance mechanisms of a system is to test the system by injecting faults and see how the system performs under faulty conditions. This paper presents an application of the focused fault injection method that has been developed for testing software implemented fault tolerance mechanisms of distributed systems. The method exploits the object oriented approach of software implementation to support the injection of specific classes of faults. With the focused fault injection method, the system tester is able to inject specific classes of faults (including malicious ones) such that the fault tolerance mechanisms of a target system can be tested adequately. The method has been applied to test the design and implementation of voting, clock synchronization, and ordering modules of the Voltan TMR (triple modular redundant) node. The tests performed uncovered three flaws in the system software.

  1. Effect of Coercive Voltage and Charge Injection on Performance of a Ferroelectric-Gate Thin-Film Transistor

    Directory of Open Access Journals (Sweden)

    P. T. Tue

    2013-01-01

    Full Text Available We adopted a lanthanum oxide capping layer between semiconducting channel and insulator layers for fabrication of a ferroelectric-gate thin-film transistor memory (FGT which uses solution-processed indium-tin-oxide (ITO and lead-zirconium-titanate (PZT film as a channel layer and a gate insulator, respectively. Good transistor characteristics such as a high “on/off” current ratio, high channel mobility, and a large memory window of 108, 15.0 cm2 V−1 s−1, and 3.5 V were obtained, respectively. Further, a correlation between effective coercive voltage, charge injection effect, and FGT’s memory window was investigated. It is found that the charge injection from the channel to the insulator layer, which occurs at a high electric field, dramatically influences the memory window. The memory window’s enhancement can be explained by a dual effect of the capping layer: (1 a reduction of the charge injection and (2 an increase of effective coercive voltage dropped on the insulator.

  2. New space-charge methods in Accsim and their application to injection in the CERN PS Booster

    CERN Document Server

    Jones, F W

    1999-01-01

    The tracking and simulation code Accsim has recently been upgraded with new treatments of transverse space charge, one based on a conventional multiple-Fourier-transform technique and another using a new hybrid-fast-multipole (HFM) method. We present the application of the code to the study of multiturn injection in the CERN PS Booster in its LHC-injector-chain operation scenario. In particular, the ability of the HFM method to accurately model the turn-by-turn stacking and subsequent development of the beam is evaluated, especially its development near the sharp cutoff produced by beam loss on the injection septum. Results are compared with measured injection efficiencies and betatron amplitude distributions. (6 refs) .

  3. Fault injection as a test method for an FPGA in charge of data readout for a large tracking detector

    CERN Document Server

    Roed, K; Richter, M; Fehlker, D; Helstrup, H; Alme, J; Ullaland, K

    2011-01-01

    This paper describes how fault injection has been implemented as a test method for an FPGA in an existing hardware configuration setup. As this FPGA is in charge of data readout for a large tracking detector, the reliability of this FPGA is of high importance. Due to the complexity of the readout electronics, irradiation testing is technically difficult at this stage of the system commissioning. The work presented in this paper is therefore motivated by introducing fault injection as an alternative method to characterize failures caused by SEUs. It is a method to study the effect that a configuration upset may have on the operation of the FPGA. The target platform consists of two independent modules for data acquisition and detector control functionality. Fault injection to test the response of the data acquisition module is made possible by implementing the solution as part of the detector control functionality. Correct implementation is validated by a simple shift register design. Our results demonstrate th...

  4. Elastin Based Cell-laden Injectable Hydrogels with Tunable Gelation, Mechanical and Biodegradation Properties

    OpenAIRE

    Fathi, Ali; Mithieux, Suzanne M.; Wei, Hua; Chrzanowski, Wojciech; Valtchev, Peter; Anthony S. Weiss; Dehghani, Fariba

    2014-01-01

    Injectable hydrogels made from extracellular matrix proteins such as elastin show great promise for various biomedical applications. Use of cytotoxic reagents, fixed gelling behavior, and lack of mechanical strength in these hydrogels are the main associated drawbacks. The aim of this study was to develop highly cytocompatible and injectable elastin-based hydrogels with alterable gelation characteristics, favorable mechanical properties and structural stability for load bearing applications. ...

  5. Mechanical properties test and microstructure analysis of polyoxymethylene (POM) micro injection moulded standard parts

    DEFF Research Database (Denmark)

    Tosello, Guido; Lucchetta, Giovanni; Hansen, Hans Nørgaard;

    2009-01-01

    The tensile mechanical properties and the micro structure of micro injection moulded polyoxymethylene (POM) test parts were investigated in this paper. The effects of different injection moulding processing conditions on ultimate tensile stress and strain at break were analyzed. Additionally, the...... effects of miniaturization on the mechanical properties were investigated by executing injection moulding with both a standard tool designed according to ISO 527-2 and a miniaturized test part obtained from the standard design by a downscaling factor 10. The experiments have been performed according to...... layer and a larger spherulitic core, low value of ultimate tensile stress and high of elongation at break....

  6. Photoinduced charge injection from excited triplet hypocrellin B into TiO2 colloid in ethanol

    Institute of Scientific and Technical Information of China (English)

    SHEN, Jian-Quan; SHEN, Tao; ZHANG, Man-Hua; LI, Wen; SONG, Ai-Min

    2000-01-01

    Photosensitization of TiO2 colloid by hypocrellin B (HB), a natural photodynamic pigment with extremely high plhotosta bility, has been studied by surface enhanced Raman spec troscorpy (SERS), laser flash photolysis and electron param agnetic resonance (EPR) techniques. The photosensitization of TiO2 occurred practically from the excited triplet dye and the electron injection rate constant is 1.3 × 106 s-1. The influ ences of donor and acceptor on the eleciron injection were in vestigated.

  7. Kerr electro-optic field mapping study of the effect of charge injection on the impulse breakdown strength of transformer oil

    Science.gov (United States)

    Zhang, X.; Zahn, M.

    2013-10-01

    The smart use of charge injection to improve breakdown strength in transformer oil is demonstrated in this paper. Hypothetically, bipolar homo-charge injection with reduced electric field at both electrodes may allow higher voltage operation without insulation failure, since electrical breakdown usually initiates at the electrode-dielectric interfaces. To find experimental evidence, the applicability and limitation of the hypothesis is first analyzed. Impulse breakdown tests and Kerr electro-optic field mapping measurements are then conducted with different combinations of parallel-plate aluminum and brass electrodes stressed by millisecond duration impulse. It is found that the breakdown voltage of brass anode and aluminum cathode is ˜50% higher than that of aluminum anode and brass cathode. This can be explained by charge injection patterns from Kerr measurements under a lower voltage, where aluminum and brass electrodes inject negative and positive charges, respectively. This work provides a feasible approach to investigating the effect of electrode material on breakdown strength.

  8. Mechanism of electrochemical charge transport in individual transition metal complexes.

    Science.gov (United States)

    Albrecht, Tim; Guckian, Adrian; Kuznetsov, Alexander M; Vos, Johannes G; Ulstrup, Jens

    2006-12-27

    We used electrochemical scanning tunneling microscopy (STM) and spectroscopy (STS) to elucidate the mechanism of electron transport through individual pyridyl-based Os complexes. Our tunneling data obtained by two-dimensional electrochemical STS and STM imaging lead us to the conclusion that electron transport occurs by thermally activated hopping. The conductance enhancement around the redox potential of the complex, which is reminiscent of switching and transistor characterics in electronics, is reflected both in the STM imaging contrast and directly in the tunneling current. The latter shows a biphasic distance dependence, in line with a two-step electron hopping process. Under conditions where the substrate/molecule electron transfer (ET) step is dominant in determining the overall tunneling current, we determined the conductance of an individual Os complex to be 9 nS (Vbias = 0.1 V). We use theoretical approaches to connect the single-molecule conductance with electrochemical kinetics data obtained from monolayer experiments. While the latter leave some controversy regarding the degree of electronic coupling, our results suggest that electron transport occurs in the adiabatic limit of strong electronic coupling. Remarkably, and in contrast to established ET theory, the redox-mediated tunneling current remains strongly distance dependent due to the electronic coupling, even in the adiabatic limit. We exploit this feature and apply it to electrochemical single-molecule conductance data. In this way, we attempt to paint a unified picture of electrochemical charge transport at the single-molecule and monolayer levels. PMID:17177467

  9. Quantitative Analysis of Charge Injection and Discharging of Si Nanocrystals and Arrays by Electrostatic Force Microscopy

    Science.gov (United States)

    Bell, L. D.; Boer, E.; Ostraat, M.; Brongersma, M. L.; Flagan, R. C.; Atwater, H. A.

    2000-01-01

    NASA requirements for computing and memory for microspacecraft emphasize high density, low power, small size, and radiation hardness. The distributed nature of storage elements in nanocrystal floating-gate memories leads to intrinsic fault tolerance and radiation hardness. Conventional floating-gate non-volatile memories are more susceptible to radiation damage. Nanocrystal-based memories also offer the possibility of faster, lower power operation. In the pursuit of filling these requirements, the following tasks have been accomplished: (1) Si nanocrystal charging has been accomplished with conducting-tip AFM; (2) Both individual nanocrystals on an oxide surface and nanocrystals formed by implantation have been charged; (3) Discharging is consistent with tunneling through a field-lowered oxide barrier; (4) Modeling of the response of the AFM to trapped charge has allowed estimation of the quantity of trapped charge; and (5) Initial attempts to fabricate competitive nanocrystal non-volatile memories have been extremely successful.

  10. A Method for Sizing Booster Charges in Pyrotechnic Mechanisms

    Science.gov (United States)

    Bement, Laurence J.

    1998-01-01

    Since no generally accepted guidelines exist on sizing booster charges to assure functional margins in pyrotechnically actuated devices, a study was conducted to provide an approach to meet this need. An existing pyrovalve was modified from a single cartridge input to a dual-cartridge input with a booster charge. The objectives of this effort were to demonstrate an energy-based functional margin approach for sizing booster charges, and to determine booster charge energy delivery characteristics in this valve. Functional margin was demonstrated by determining the energy required to actuate the valve through weight drop tests for comparison to the energy delivered by the cartridge and booster charge in firings in the modified valve. The results of this study indicated that this energy-based approach fully met the study objectives, showing its usefulness for this and possibly other pyrotechnic devices.

  11. Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

    Science.gov (United States)

    Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

    1987-01-01

    A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

  12. Characterization of wafer charging mechanisms and oxide survival prediction methodology

    International Nuclear Information System (INIS)

    Unipolar, EEPROM-based peak potential sensors and current sensors have been used to characterize the I-V relationship of charging transients which devices normally experience during the course of ion implantation. The results indicate that the charging sources may appear to behave like current-sources or voltage-sources, depending on the impedance of the load. This behavior may be understood in terms of plasma concepts. The ability to empirically characterize the I-V characteristics of charging sources using the CHARM-2 monitor wafers opens the way for prediction of failure rates of oxides subjected to specific processes, if the oxide Qbd distributions are known

  13. Acceleration of energetic particles by whistler waves in active space experiment with charged particle beams injection

    Czech Academy of Sciences Publication Activity Database

    Baranets, N.; Ruzhin, Y.; Erokhin, N.; Afonin, V.; Vojta, Jaroslav; Šmilauer, Jan; Kudela, K.; Matišin, J.; Ciobanu, M.

    2012-01-01

    Roč. 49, č. 5 (2012), s. 859-871. ISSN 0273-1177 Institutional support: RVO:68378289 Keywords : Electron beam injection * Whistler waves * Wave-particle interaction Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.183, year: 2012 http://www.sciencedirect.com/science/article/pii/S0273117711007976

  14. Experimental Investigation on Dilation Mechanisms of Land-Facies Karamay Oil Sand Reservoirs under Water Injection

    Science.gov (United States)

    Lin, Botao; Jin, Yan; Pang, Huiwen; Cerato, Amy B.

    2016-04-01

    The success of steam-assisted gravity drainage (SAGD) is strongly dependent on the formation of a homogeneous and highly permeable zone in the land-facies Karamay oil sand reservoirs. To accomplish this, hydraulic fracturing is applied through controlled water injection to a pair of horizontal wells to create a dilation zone between the dual wells. The mechanical response of the reservoirs during this injection process, however, has remained unclear for the land-facies oil sand that has a loosely packed structure. This research conducted triaxial, permeability and scanning electron microscopy (SEM) tests on the field-collected oil sand samples. The tests evaluated the influences of the field temperature, confining stress and injection pressure on the dilation mechanisms as shear dilation and tensile parting during injection. To account for petrophysical heterogeneity, five reservoir rocks including regular oil sand, mud-rich oil sand, bitumen-rich oil sand, mudstone and sandstone were investigated. It was found that the permeability evolution in the oil sand samples subjected to shear dilation closely followed the porosity and microcrack evolutions in the shear bands. In contrast, the mudstone and sandstone samples developed distinct shear planes, which formed preferred permeation paths. Tensile parting expanded the pore space and increased the permeability of all the samples in various degrees. Based on this analysis, it is concluded that the range of injection propagation in the pay zone determines the overall quality of hydraulic fracturing, while the injection pressure must be carefully controlled. A region in a reservoir has little dilation upon injection if it remains unsaturated. Moreover, a cooling of the injected water can strengthen the dilation potential of a reservoir. Finally, it is suggested that the numerical modeling of water injection in the Karamay oil sand reservoirs must take into account the volumetric plastic strain in hydrostatic loading.

  15. Controlled positive and negative surface charge injection and erasure in a GaAs/AlGaAs based microdevice by scanning probe microscopy

    International Nuclear Information System (INIS)

    In this paper, we show that positive and negative charges can be injected into the surface of SiO2/Si3N4/SiO2/GaAs/AlGaAs heterostructure material by using a biased tip of a scanning probe microscope. Furthermore, the injected charges can be erased with the same tip once grounded, working in slow scan and contact mode. Surface potential measurements by quantitative analysis of Kelvin probe force microscopy after drawing and erasing charges at room temperature are presented and discussed

  16. Electron injection and transport mechanism in organic devices based on electron transport materials

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M A; Xu Wei; Khizar-ul-Haq; Zhang Xiaowen; Bai Yu; Jiang, X Y; Zhang, Z L; Zhu, W Q [Department of Materials Science, Shanghai University, Jiading 201800 (China)

    2008-11-21

    Electron injection and transport in organic devices based on electron transport (ET) materials, such as 4,7- diphyenyl-1,10-phenanthroline (Bathophenanthroline BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Bathocuproine BCP) and bipyridyl oxadiazole compound 1,3-bis [2-(2,2'-bipyridin-6-yl)-1,3,4-oxadiazol-5-yl]benzene (Bpy-OXD), have been reported. The devices are composed of ITO/ET materials (BPhen, BCP Bpy-OXD)/cathodes, where cathodes = Au, Al and Ca. Current-voltage characteristics of each ET material are performed as a function of cathodes. We have found that Ca and Al exhibit quite different J-V characteristics compared with the gold (Au) cathode. The current is more than one order of magnitude higher for the Al cathode and more than three orders of magnitude higher for Ca compared with that of the Au cathode at {approx}8 V for all ET materials. This is because of the relatively low energy barrier at the organic/metal interface for Ca and Al cathodes. Electron-only devices with the Au cathode show that the electron transfer limitation is located at the organic/cathode interface and the Fowler-Nordheim mechanism is qualitatively consistent with experimental data at high voltages. With Ca and Al cathodes, electron conduction is preponderant and is bulk limited. A power law dependence J {approx} V{sup m} with m > 2 is consistent with the model of trap-charge limited conduction. The total electron trap density is estimated to be {approx}5 x 10{sup 18} cm{sup -3}. The critical voltage (V{sub c}) is found to be {approx}45 V and is almost independent of the materials.

  17. Controlling charge injection properties in polymer field-effect transistors by incorporation of solution processed molybdenum trioxide.

    Science.gov (United States)

    Long, Dang Xuan; Xu, Yong; Wei, Huai-xin; Liu, Chuan; Noh, Yong-Young

    2015-08-21

    A simply and facilely synthesized MoO3 solution was developed to fabricate charge injection layers for improving the charge-injection properties in p-type organic field-effect transistors (OFETs). By dissolving MoO3 powder in ammonium (NH3) solvent under an air atmosphere, an intermediate ammonium molybdate ((NH4)2MoO4) precursor is made stable, transparent and spin-coated to form the MoO3 interfacial layers, the thickness and morphology of which can be well-controlled. When the MoO3 layer was applied to OFETs with a cost-effective molybdenum (Mo) electrode, the field-effect mobility (μFET) was significantly improved to 0.17 or 1.85 cm(2) V(-1)s(-1) for polymer semiconductors, regioregular poly(3-hexylthiophene) (P3HT) or 3,6-bis-(5bromo-thiophen-2-yl)-N,N'-bis(2-octyl-1-dodecyl)-1,4-dioxo-pyrrolo[3,4-c]pyrrole (DPPT-TT), respectively. Device analysis indicates that the MoO3-deposited Mo contact exhibits a contact resistance RC of 1.2 MΩ cm comparable to that in a device with the noble Au electrode. Kelvin-probe measurements show that the work function of the Mo electrode did not exhibit a dependence on the thickness of MoO3 film. Instead, ultraviolet photoemission spectroscopy results show that a doping effect is probably induced by casting the MoO3 layer on the P3HT semiconductor, which leads to the improved hole injection. PMID:26179975

  18. Study on numerical simulation of spontaneous combustion prevention mechanism by nitrogen injection in goaf

    Institute of Scientific and Technical Information of China (English)

    LI Zong-xiang; HE Bao; JIA Jin-zhang

    2006-01-01

    Based on heterogeneous and porous medium seepage of air leakage-diffusion equation, as well as, gas and porous medium synthesis heat transferring equation, a spontaneous combustion non-steady numerical model of nitrogen injection goaf was established, which can be solved by upwind finite element numerical simulation method simultaneously. Taking the working face for example; air leakage seepage, nitrogen flow and gas distribution can be described in visual display in nitrogen injection goaf and the oxygen (O2), carbon monoxide (CO) concentration and temperature distribution, as well as, their change were described in theory during the coal left behind combustion in goaf, which above reveals the complex mechanics course (mechanism) of seepage, diffusion and oxidation heat releasing during coal spontaneous combustion and its restraining. During the calculation, the effect factors of gas springing out and working face advancing were considered fully, and the spontaneous combustion course under different amount of nitrogen injection was simulated. The conclusions were obtained that under nitrogen injection condition, the high spontaneous combustion temperature area lean to the inlet air, but the shape becomes narrower, with the amount of nitrogen rising, the spontaneous combustion period becomes longer till to it does not happen. Meanwhile the nitrogen injection accelerates gas springing out in goaf. The result that turns out in theory simulation fits to practical nitrogen injection.

  19. Injection line of 1+ ion beam for electron beam ion-charge breeding source and related beam elements

    International Nuclear Information System (INIS)

    Main purpose of the electron beam ion-charge breeding source (EBIBS) is to produce highly pure and highly charged ion beam from single charge ion of stable or radioactive species. It can accept low emittance ion beam from either online or offline ECR ion sources (ECRIS). The emittance of the extracted beam is low at lower RF frequencies and magnetic field of the ECRIS. The beam at the position of extraction is approximately reproduced at the entrance of the electron collector of the EBIBS. The beam moves forward under the influence of the negative potential deep of the electron beam and enters the ionization region in solenoid field of the EBIBS. The injection line starts at the extraction region of the ECRIS. The assumed parameters of the extracted beam of 20 keV energy and 0.0732 GeV/c momentum for injection are 10 mm diameter and 30 mrad beam divergence cone. As mass number of the ions decreases the energy decreases for constant momentum of the ion beam. The value of the momentum or the beam rigidity is judiciously chosen to encompass the most of the isotopes of various elements. The beam is focused by a quadrupole doublet and passes the beam through a 90° bending magnet. The beam is analyzed also by the dipole magnet to remove the contaminants and the selected ion beam is focused by a quadrupole doublet magnet to pass through an electrostatic 90° bending elements. The beam approaches the opening of 16 mm diameter of the electron collector. A round beam of 12 mm diameter is achieved here with the help of a quadrupole triplet through point-to-point imaging from start to the end. The transport matrices for the electrostatic bending elements were calculated and incorporated into the TRANSPORT code. (author)

  20. Energy mechanism of charges analyzed in real current environment

    CERN Document Server

    Ianconescu, R; Ianconescu, Reuven

    2003-01-01

    We analyze in this work the energy transfer process of accelerated charges, the mass fluctuations accompanying this process, and their inertial properties. Based on a previous work, we use here the dipole antenna, which is a very convenient framework for such analysis, for analyzing those characteristics. We show that the radiation process can be viewed by two energy transfer processes: one from the energy source to the charges and the second from the charges into the surrounding space. Those processes, not being in phase, result in mass fluctuations. The same principle is true during absorption. We show that in a transient period between absorption and radiation the dipole antenna gains mass according to the amount of absorbed energy and loses this mass as radiated energy. We rigorously prove that the gain of mass, resulting from electrical interaction has inertial properties in the sense of Newton's third low. We arrive to this result by modeling the reacting spacetime region by an electric dipole.

  1. A New Mechanism of Higgs Bosons in Producing Charge Particles

    DEFF Research Database (Denmark)

    Javadi, Hossein; Forouzbakhsh, Farshid

    2006-01-01

    A new production method of elementary particles by Higgs Bosons will be shown. But before that the structure of photon will be considered deeply, while a new definition of Higgs Boson about color-charges and color-magnet will be given for the first time.......A new production method of elementary particles by Higgs Bosons will be shown. But before that the structure of photon will be considered deeply, while a new definition of Higgs Boson about color-charges and color-magnet will be given for the first time....

  2. Origin of traps and charge transport mechanism in hafnia

    Energy Technology Data Exchange (ETDEWEB)

    Islamov, D. R., E-mail: damir@isp.nsc.ru; Gritsenko, V. A., E-mail: grits@isp.nsc.ru [Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Cheng, C. H. [Department of Mechatronic Technology, National Taiwan Normal University, Taipei 106, Taiwan (China); Chin, A., E-mail: albert-achin@hotmail.com [National Chiao Tung University, Hsinchu 300, Taiwan (China)

    2014-12-01

    In this study, we demonstrated experimentally and theoretically that oxygen vacancies are responsible for the charge transport in HfO{sub 2}. Basing on the model of phonon-assisted tunneling between traps, and assuming that the electron traps are oxygen vacancies, good quantitative agreement between the experimental and theoretical data of current-voltage characteristics was achieved. The thermal trap energy of 1.25 eV in HfO{sub 2} was determined based on the charge transport experiments.

  3. Discussion on Mechanism of Breech-Blow Caused by Propellant Charge

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    From the view point of launch safety caused by fracture of propellant charge, this paper points out that the safety criterion of pressure wave is inadequate to evaluate the launch safety of propellant charge based on the initial negative differential pressure and sensitivity tests. Generally, the maximum barrel pressure does not depend upon the intensity of pressure wave correspondingly. The pressure wave intensity can not describe the fracture degree of propellant charge in chamber and reflect the mechanical environment of propellant charge fracturing exactly and wholly. The evaluation criterion for launch safety of propellant charge should be built on the basis of depicting the fracture degree of propellant bed.

  4. Charge Effects on Mechanical Properties of Elastomeric Proteins

    Science.gov (United States)

    Kappiyoor, Ravi; Balasubramanian, Ganesh; Dudek, Daniel; Puri, Ishwar

    2012-02-01

    Several biological molecules of nanoscale dimensions, such as elastin and resilin, are capable of performing diverse tasks with minimal energy loss. These molecules are efficient in that the ratio of energy output to energy consumed is very close to unity. This is in stark contrast to some of the best synthetic materials that have been created. For example, it is known that resilin found in dragonflies has a hysteresis loss of only 0.8% of the energy input while the best synthetic rubber made to date, polybutadiene, has a loss of roughly 20%.We simulate tensile tests of naturally occurring motifs found in resilin (a highly hydrophilic protein), as well as similar simulations found in reduced-polarity counterparts (i.e. the same motif with the charge on each individual atom set to half the natural value, the same motif with the charge on each individual atom set to zero, and a motif in which all the polar amino acids have been replaced with nonpolar amino acids). The results show a strong correlation between charge and extensibility. In order to further understand the effect of properties such as charge on the system, we will run simulations of elastomeric proteins such as resilin in different solvents.

  5. Heavy Inertial Confinement Energy: Interactions Involoving Low charge State Heavy Ion Injection Beams

    Energy Technology Data Exchange (ETDEWEB)

    DuBois, Robert D

    2006-04-14

    During the contract period, absolute cross sections for projectile ionization, and in some cases for target ionization, were measured for energetic (MeV/u) low-charge-state heavy ions interacting with gases typically found in high and ultra-high vacuum environments. This information is of interest to high-energy-density research projects as inelastic interactions with background gases can lead to serious detrimental effects when intense ion beams are accelerated to high energies, transported and possibly confined in storage rings. Thus this research impacts research and design parameters associated with projects such as the Heavy Ion Fusion Project, the High Current and Integrated Beam Experiments in the USA and the accelerator upgrade at GSI-Darmstadt, Germany. Via collaborative studies performed at GSI-Darmstadt, at the University of East Carolina, and Texas A&M University, absolute cross sections were measured for a series of collision systems using MeV/u heavy ions possessing most, or nearly all, of their bound electrons, e.g., 1.4 MeV/u Ar{sup +}, Xe{sup 3+}, and U{sup 4,6,10+}. Interactions involving such low-charge-state heavy ions at such high energies had never been previously explored. Using these, and data taken from the literature, an empirical model was developed for extrapolation to much higher energies. In order to extend our measurements to much higher energies, the gas target at the Experimental Storage Ring in GSI-Darmstadt was used. Cross sections were measured between 20 and 50 MeV/u for U{sup 28+}- H{sub 2} and - N{sub 2}, the primary components found in high and ultra-high vacuum systems. Storage lifetime measurements, information inversely proportional to the cross section, were performed up to 180 MeV/u. The lifetime and cross section data test various theoretical approaches used to calculate cross sections for many-electron systems. Various high energy density research projects directly benefit by this information. As a result, the general

  6. Impact of Mechanical Forces in a 25kA Current Injection Transformer

    Directory of Open Access Journals (Sweden)

    H. Heydari

    2007-12-01

    Full Text Available Since Current Injection transformer (CIT systems are within the major group of the standard type test equipments in electrical industry, their performances are very important. When designing a high current devices, there are many factors to be considered from which, unharmful effects of mechanical forces due to high current (25kA passing through secondary winding of a CIT must be ensured. Since the electromagnetic forces is proportional to the square of current, up to the present time, as far as the authors are aware no report on impact of mechanical forces considerations for current injection devices has been made. This paper attempts to fill this void in our knowledge by considering various issues related to the mechanical forces in a 25kA CIT, using 2D electromagnetic fields (EMFs simulation tools (Ansys 8.1 to calculate stray reactance fields and the mechanical forces in a single turn secondary winding of the CIT.

  7. Quality control and process capability assessment for injection-moulded micro mechanical parts

    DEFF Research Database (Denmark)

    Gasparin, Stefania; Tosello, Guido; Hansen, Hans Nørgaard;

    2013-01-01

    Quality control of micro components is an increasing challenge. Smaller mechanical parts are characterized by smaller tolerance to be verified. This paper focuses on the dimensional verification of micro injection-moulded components selected from an industrial application. These parts are measure...

  8. Design process of the nanofluid injection mechanism in nuclear power plants

    Directory of Open Access Journals (Sweden)

    Bang In Choel

    2011-01-01

    Full Text Available Abstract Nanofluids, which are engineered suspensions of nanoparticles in a solvent such as water, have been found to show enhanced coolant properties such as higher critical heat flux and surface wettability at modest concentrations, which is a useful characteristic in nuclear power plants (NPPs. This study attempted to provide an example of engineering applications in NPPs using nanofluid technology. From these motivations, the conceptual designs of the emergency core cooling systems (ECCSs assisted by nanofluid injection mechanism were proposed after following a design framework to develop complex engineering systems. We focused on the analysis of functional requirements for integrating the conventional ECCSs and nanofluid injection mechanism without loss of performance and reliability. Three candidates of nanofluid-engineered ECCS proposed in previous researches were investigated by applying axiomatic design (AD in the manner of reverse engineering and it enabled to identify the compatibility of functional requirements and potential design vulnerabilities. The methods to enhance such vulnerabilities were referred from TRIZ and concretized for the ECCS of the Korean nuclear power plant. The results show a method to decouple the ECCS designs with the installation of a separate nanofluids injection tank adjacent to the safety injection tanks such that a low pH environment for nanofluids can be maintained at atmospheric pressure which is favorable for their injection in passive manner.

  9. Quantification of mechanical effect on the migration of injected CO2 in brine aquifers

    Science.gov (United States)

    Lin, C.; Ni, C.; Lee, I.; Lu, C.

    2012-12-01

    Geologic storage of carbon dioxide (CO2) offers a favorable scheme of the solution to the problem of global climate change. In hydrodynamic of geology, permeability (k) and porosity (φ ) play important roles, which control the migration of CO2 plume gas saturation for structural and stratigraphic trapping. During the periods of CO2 injected into objective storage formations, the effective stress of geologic formations can be changed with the injection pressures. Such variation of effective stress will lead to the variation of k and φ and then feedback to govern the injection rates and injection time of CO2. In this study, we modified the well-developed TOUGHREACT model to be able to include the mechanical effect on the k and φ during the simulations. The mathematical formulas for effective stress versus k and φ are employed to calculate the variation of k and φ. A one-dimensional synthetic example and a field-scale three-dimensional example with injection rate of 100 Mt/year were used to illustrate the migration of CO2 in geologic formation. The selected field-scale injection site is located in Kueichulin Formation in central Taiwan. Simulation results for synthetic example show that the modified program can successfully calculate the CO2 migrations based on the specified k and φ formulas. However, the variation of effective stress caused by increase of hydraulic fluid pressure is insignificant. Such result can be caused by relatively small increase of hydraulic pressure for the 100Mt/year injection rate. A sensitivity analysis is also conducted for the field-scale problem to evaluate the sensitivity of injection rates on the variation of CO2 migration.

  10. Transfer and trapping of charge injected directly into DNA by ionizing radiation

    International Nuclear Information System (INIS)

    Most of the stable end products that are produced by the direct ionization of DNA are derived from early events involving one-electron oxidation (hole formation) and one-electron reduction (electron addition). The probability that a hole will be injected in a particular component of DNA is directly proportional to the electron density of the component. In dry DNA, the initial hole distribution, therefore, is 58 % on the sugar phosphate backbone and 42 % on the bases. Inclusion of DNA's solvation shell, doubles the target mass, resulting in about half the initial holes being formed in the solvation shell and the other half in DNA. The ejected electrons are preferentially trapped by DNA bases. The goal of our work is to determine how the injected holes and electrons migrate through DNA and what reactions lead to shallow (reversible) traps and deep (irreversible) traps. Our approach is to use EPR spectroscopy to study the unstable free radical intermediates and HPLC to study the stable end products in the same DNA samples. Crystalline DNA is used in order to maximize the structural knowledge of the samples and minimize errors due to sample variability. From our findings we argue that 1) hole transfer from the solvation shell to DNA distributes either evenly between the sugar and bases or with a bias for the sugar, 2) hole transfer from the backbone to the bases competes with irreversible trapping at the sugar by deprotonation of the sugar-phosphate radical cation, 3) the rate of hole transfer from backbone to base is independent of base type, and 4) a small fraction of excess electrons are permanently trapped by double protonation of the cytosine radical anion. The possible biological implications of these findings will be discussed. Supported by PHS Grant R37-CA 32546, awarded by NCI, DHHS

  11. Charge-injection-device performance in the high-energy-neutron environment of laser-fusion experiments

    International Nuclear Information System (INIS)

    Charge-injection devices (CIDs) are being used to image x rays in laser-fusion experiments on the University of Rochester's OMEGA Laser System. The CID cameras are routinely used up to the maximum neutron yields generated (∼1014 DT). The detectors are deployed in x-ray pinhole cameras and Kirkpatrick-Baez microscopes. The neutron fluences ranged from ∼107 to ∼109 neutrons/cm2 and useful x-ray images were obtained even at the highest fluences. It is intended to use CID cameras at the National Ignition Facility (NIF) as a supporting means of recording x-ray images. The results of this work predict that x-ray images should be obtainable on the NIF at yields up to ∼1015, depending on distance and shielding.

  12. Classification of the ejection mechanisms of charged macromolecules from liquid droplets

    Science.gov (United States)

    Consta, Styliani; Malevanets, Anatoly

    2013-01-01

    The relation between the charge state of a macromolecule and its ejection mechanism from droplets is one of the important questions in electrospray ionization methods. In this article, effects of solvent-solute interaction on the manifestation of the charge induced instability in a droplet are examined. We studied the instabilities in a prototype system of a droplet comprised of charged poly(ethylene glycol) and methanol, acetonitrile, and water solvents. We observed instances of three, previously only conjectured, [S. Consta, J. Phys. Chem. B 114, 5263 (2010), 10.1021/jp912119v] mechanisms of macroion ejection. The mechanism of ejection of charged macroion in methanol is reminiscent of "pearl" model in polymer physics. In acetonitrile droplets, the instability manifests through formation of solvent spines around the solvated macroion. In water, we find that the macroion is ejected from the droplet through contiguous extrusion of a part of the chain. The difference in the morphology of the instabilities is attributed to the interplay between forces arising from the macroion solvation energy and the surface energy of the droplet interface. For the contiguous extrusion of a charged macromolecule from a droplet, we demonstrate that the proposed mechanism leads to ejection of the macromolecule from droplets with sizes well below the Rayleigh limit. The ejected macromolecule may hold charge significantly higher than that suggested by prevailing theories. The simulations reveal new mechanisms of macroion evaporation that differ from conventional charge residue model and ion evaporation mechanisms.

  13. Experimental study of combustion and emission characteristics of ethanol fuelled port injected homogeneous charge compression ignition (HCCI) combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

    2011-04-15

    The homogeneous charge compression ignition (HCCI) is an alternative combustion concept for in reciprocating engines. The HCCI combustion engine offers significant benefits in terms of its high efficiency and ultra low emissions. In this investigation, port injection technique is used for preparing homogeneous charge. The combustion and emission characteristics of a HCCI engine fuelled with ethanol were investigated on a modified two-cylinder, four-stroke engine. The experiment is conducted with varying intake air temperature (120-150 C) and at different air-fuel ratios, for which stable HCCI combustion is achieved. In-cylinder pressure, heat release analysis and exhaust emission measurements were employed for combustion diagnostics. In this study, effect of intake air temperature on combustion parameters, thermal efficiency, combustion efficiency and emissions in HCCI combustion engine is analyzed and discussed in detail. The experimental results indicate that the air-fuel ratio and intake air temperature have significant effect on the maximum in-cylinder pressure and its position, gas exchange efficiency, thermal efficiency, combustion efficiency, maximum rate of pressure rise and the heat release rate. Results show that for all stable operation points, NO{sub x} emissions are lower than 10 ppm however HC and CO emissions are higher. (author)

  14. Effect of hydrogen charging on the mechanical properties of medium strength aluminium alloys 2091 and 2014

    DEFF Research Database (Denmark)

    Bandopadhyay, A.; Ambat, Rajan; Dwarakadasa, E.S.

    1992-01-01

    Cathodic hydrogen charging in 3.5% NaCl solution altered the mechanical properties of 2091-T351 (Al-Cu-Li-Mg-Zr) determined by a slow (10(-3)/s) strain rate tensile testing technique. UTS and YS decreased in the caw of 2091-T351 and 2014-T6(Al-Cu-Mn-Si-Mg) with increase in charging current density....... Elongation showed a decrease with increase in charging current density for both the alloys. However, elongation occurring throughout the gauge length in uncharged specimens changed over to localized deformation, thus increasing the reduction in area in charged specimens. A transition in fracture mode from...

  15. In vivo demonstration of injectable microstimulators based on charge-balanced rectification of epidermically applied currents

    Science.gov (United States)

    Ivorra, Antoni; Becerra-Fajardo, Laura; Castellví, Quim

    2015-12-01

    Objective. It is possible to develop implantable microstimulators whose actuation principle is based on rectification of high-frequency (HF) current bursts supplied through skin electrodes. This has been demonstrated previously by means of devices consisting of a single diode. However, previous single diode devices caused dc currents which made them impractical for clinical applications. Here flexible thread-like stimulation implants which perform charge balance are demonstrated in vivo. Approach. The implants weigh 40.5 mg and they consist of a 3 cm long tubular silicone body with a diameter of 1 mm, two electrodes at opposite ends, and, within the central section of the body, an electronic circuit made up of a diode, two capacitors, and a resistor. In the present study, each implant was percutaneously introduced through a 14 G catheter into either the gastrocnemius muscle or the cranial tibial muscle of a rabbit hindlimb. Then stimulation was performed by delivering HF bursts (amplitude intramuscular stimulation implants ever assayed in vertebrates.

  16. Charge Transfer Characteristics and Initiation Mechanisms of Long Delayed Sprites

    Science.gov (United States)

    Li, J.; Cummer, S. A.; Lyons, W. A.; Nelson, T. E.

    2007-12-01

    Simultaneous measurements of high altitude optical emissions and the magnetic field produced by sprite-associated lightning discharges enable a close examination of the link between low altitude lightning process and high altitude sprite process. In this work, we report results of the coordinated analysis of high speed (1000--10000 frames per second) sprite video and wideband (0.1 Hz to 30 kHz) magnetic field measurements made simultaneously at the Yucca Ridge Field Station and Duke University during the June through August 2005 campaign period. During the observation period, the high speed camera detected 83 sprite events in 67 TLE sequences, which are caused by the same number of +CGs. 46% of these sprite events are delayed more than 10 ms after the lightning return stroke. With the estimated lightning source current moment waveform, we computed the continuing current amplitude and total charge transfer characteristics of the long delayed sprites (>10 ms delay). Our calculation shows the total charge moment change of the long delayed sprites can vary from several hundred C km to more than ten thousand C km. All the long delayed sprites are related with intense continuing current bigger than 2 kA. This continuing current provides about 50% to 90% of the total charge transfer. However, a bigger continuing current does not necessarily mean a shorter time delay. This indicates that other processes also involved in the sprite initiation for long delayed sprites. In our observations, the sferic burst, a high frequency noise caused by intra-cloud activity, is always accompanied by a slow intensification in the lightning source current before the time of sprite initiation. Thus we used the lightning source current as an input and employed a 2-D FDTD model to numerically simulate the electric field at different altitudes and compare it with the breakdown field. Including the effect of the electron mobility dependence on electric field, the simulation results showed that

  17. Particle morphology influence on mechanical and biocompatibility properties of injection molded Ti alloy powder.

    Science.gov (United States)

    Gülsoy, H Özkan; Gülsoy, Nagihan; Calışıcı, Rahmi

    2014-01-01

    Titanium and Titanium alloys exhibits properties that are excellent for various bio-applications. Metal injection molding is a processing route that offers reduction in costs, with the added advantage of near net-shape components. Different physical properties of Titanium alloy powders, shaped and processed via injection molding can achieve high complexity of part geometry with mechanical and bioactivity properties, similar or superior to wrought material. This study describes that the effect of particle morphology on the microstructural, mechanical and biocompatibility properties of injection molded Ti-6Al-4V (Ti64) alloy powder for biomaterials applications. Ti64 powders irregular and spherical in shape were injection molded with wax based binder. Binder debinding was performed in solvent and thermal method. After debinding the samples were sintered under high vacuum. Metallographic studies were determined to densification and the corresponding microstructural changes. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. The results show that spherical and irregular powder could be sintered to a maximum theoretical density. Maximum tensile strength was obtained for spherical shape powder sintered. The tensile strength of the irregular shape powder sintered at the same temperature was lower due to higher porosity. Finally, mechanical tests show that the irregular shape powder has lower mechanical properties than spherical shape powder. The sintered irregular Ti64 powder exhibited better biocompatibility than sintered spherical Ti64 powder. Results of study showed that sintered spherical and irregular Ti64 powders exhibited high mechanical properties and good biocompatibility properties. PMID:25201399

  18. Mechanism of charge recombination in meso-structured organic-inorganic hybrid perovskite solar cells: A macroscopic perspective

    Science.gov (United States)

    Yang, Wenchao; Yao, Yao; Wu, Chang-Qin

    2015-04-01

    In the currently popular organic-inorganic hybrid perovskite solar cells, the slowness of the charge recombination processes is found to be a key factor for contributing to their high efficiencies and high open circuit voltages, but the underlying recombination mechanism remains unclear. In this work, we investigate the bimolecular recombination (BR) and the trap-assisted monomolecular recombination (MR) in meso-structured perovskite solar cells under steady state working condition, and try to reveal their roles on determining the device performance. Some interfacial effects such as the injection barriers at the selective contacts are examined as well. Based on the macroscopic device modeling, the recombination resistance-voltage (Rrec-V) and the current density-voltage (J-V) curves are calculated to characterize the recombination mechanism and describe the device performance, respectively. Through comparison with the impedance spectroscopy extracted Rrec data, it is found that under the typical BR reduction factor and deep trap densities observed in experiments, the MR dominates the charge recombination in the low voltage regime, while the BR dominates in the high voltage regime. The short circuit current and the fill factor could be reduced by the significant MR but the open circuit voltage is generally determined by the BR. The different electron injection barriers at the contact can change the BR rate and induce different patterns for the Rrec-V characteristics. For the perovskites of increased band gaps, the Rrec's are significantly enhanced, corresponding to the high open circuit voltages. Finally, it is revealed that the reduced effective charge mobility due to the transport in electron and hole transporting material makes the Rrec decrease slowly with the increasing voltage, which leads to increased open circuit voltage.

  19. Mechanism of charge recombination in meso-structured organic-inorganic hybrid perovskite solar cells: A macroscopic perspective

    International Nuclear Information System (INIS)

    In the currently popular organic-inorganic hybrid perovskite solar cells, the slowness of the charge recombination processes is found to be a key factor for contributing to their high efficiencies and high open circuit voltages, but the underlying recombination mechanism remains unclear. In this work, we investigate the bimolecular recombination (BR) and the trap-assisted monomolecular recombination (MR) in meso-structured perovskite solar cells under steady state working condition, and try to reveal their roles on determining the device performance. Some interfacial effects such as the injection barriers at the selective contacts are examined as well. Based on the macroscopic device modeling, the recombination resistance-voltage (Rrec−V) and the current density-voltage (J–V) curves are calculated to characterize the recombination mechanism and describe the device performance, respectively. Through comparison with the impedance spectroscopy extracted Rrec data, it is found that under the typical BR reduction factor and deep trap densities observed in experiments, the MR dominates the charge recombination in the low voltage regime, while the BR dominates in the high voltage regime. The short circuit current and the fill factor could be reduced by the significant MR but the open circuit voltage is generally determined by the BR. The different electron injection barriers at the contact can change the BR rate and induce different patterns for the Rrec–V characteristics. For the perovskites of increased band gaps, the Rrec's are significantly enhanced, corresponding to the high open circuit voltages. Finally, it is revealed that the reduced effective charge mobility due to the transport in electron and hole transporting material makes the Rrec decrease slowly with the increasing voltage, which leads to increased open circuit voltage

  20. Laser-induced forward transfer of polymer light-emitting diode pixels with increased charge injection.

    Science.gov (United States)

    Shaw-Stewart, James; Lippert, Thomas; Nagel, Matthias; Nüesch, Frank; Wokaun, Alexander

    2011-02-01

    Laser-induced forward transfer (LIFT) has been used to print 0.6 mm × 0.5 mm polymer light-emitting diode (PLED) pixels with poly[2-methoxy, 5-(2-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as the light-emitting polymer. The donor substrate used in the LIFT process is covered by a sacrificial triazene polymer (TP) release layer on top of which the aluminium cathode and functional MEH-PPV layers are deposited. To enhance electron injection into the MEH-PPV layer, a thin poly(ethylene oxide) (PEO) layer on the Al cathode or a blend of MEH-PPV and PEO was used. These donor substrates have been transferred onto both plain indium tin oxide (ITO) and bilayer ITO/PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) blend) receiver substrates to create the PLED pixels. For comparison, devices were fabricated in a conventional manner on ITO substrates coated with a PEDOT:PSS hole-transporting layer. Compared to multilayer devices without PEO, devices with ITO/PEDOT:PSS/MEH-PPV:PEO blend/Al architecture show a 100 fold increase of luminous efficiency (LE) reaching a maximum of 0.45 cd/A for the blend at a brightness of 400 cd/m(2). A similar increase is obtained for the polymer light-emitting diode (PLED) pixels deposited by the LIFT process, although the maximum luminous efficiency only reaches 0.05 cd/A for MEH-PPV:PEO blend, which we have attributed to the fact that LIFT transfer was carried out in an ambient atmosphere. For all devices, we confirm a strong increase in device performance and stability when using a PEDOT:PSS film on the ITO anode. For PLEDs produced by LIFT, we show that a 25 nm thick PEDOT:PSS layer on the ITO receiver substrate considerably reduces the laser fluence required for pixel transfer from 250 mJ/cm(2) without the layer to only 80 mJ/cm(2) with the layer. PMID:21261274

  1. Evaluation of Mechanical Properties of Injection Molding Composites Reinforced by Bagasse Fiber

    Science.gov (United States)

    Cao, Yong; Fukumoto, Isao

    BMC (Bulk Molding Compound) is composed of UP (Unsaturated Polyester) resin, glass fibers, and bagasse fibers which have been obtained after squeezing sugar cane. Our purpose is to use the bagasse fibers as reinforcement and filler in BMC to fabricate composites by injection molding and injection compression molding. The mechanical properties of injection molding composites were improved after adding the bagasse fibers. Observing the fracture surface of the tensile test specimen through SEM, we could notice the glass fibers were penetrated into the bagasse fibers longitudinally. Along with UP resin solidifying, the glass fibers were firmly fixed in the bagasse fibers and finally united with them. This phenomenon could bring on the same effect as the glass fibers length was prolonged, so that the adhesion interface between fiber and matrix resin became larger, which leads to the increase in the mechanical properties. Otherwise, it was observed that UP resin sufficiently permeated the bagasse fibers and solidified. This also contributes to enhancing the mechanical properties drastically.

  2. Modeling charged defects, dopant diffusion and activation mechanisms for TCAD simulations using kinetic Monte Carlo

    International Nuclear Information System (INIS)

    This work will show how the kinetic Monte Carlo (KMC) technique is able to successfully model the defects and diffusion of dopants in Si-based materials for advanced microelectronic devices, especially for non-equilibrium conditions. Charge states of point defects and paired dopants are also simulated, including the dependency of the diffusivities on the Fermi level and charged particle drift coming from the electric field. The KMC method is used to simulate the diffusion of the point defects, and formation and dissolution of extended defects, whereas a quasi-atomistic approach is used to take into account the carrier densities. The simulated mechanisms include the kick-out diffusion mechanism, extended defect formation and the activation/deactivation of dopants through the formation of impurity clusters. Damage accumulation and amorphization are also taken into account. Solid phase epitaxy regrowth is included, and also the dopants redistribution during recrystallization of the amorphized regions. Regarding the charged defects, the model considers the dependencies of charge reactions, electric bias, pairing and break-up reactions according to the local Fermi level. Some aspects of the basic physical mechanisms have also been taken into consideration: how to smooth out the atomistic dopant point charge distribution, avoiding very abrupt and unphysical charge profiles and how to implement the drift of charged particles into the existing electric field. The work will also discuss the efficiency, accuracy and relevance of the method, together with its implementation in a technology computer aided design process simulator

  3. Evidence for high-energy and low-emittance electron beams using ionization injection of charge in a plasma wakefield accelerator

    CERN Document Server

    Vafaei-Najafabadi, N; Clayton, C E; Joshi, C; Marsh, K A; Mori, W B; Welch, E C; Lu, W; Adli, E; Allen, J; Clarke, C I; Corde, S; Frederico, J; Gessner, S J; Green, S Z; Hogan, M J; Litos, M D; Yakimenko, V

    2015-01-01

    Ionization injection in a plasma wakefield accelerator was investigated experimentally using two lithium plasma sources of different lengths. The ionization of the helium gas, used to confine the lithium, injects electrons in the wake. After acceleration, these injected electrons were observed as a distinct group from the drive beam on the energy spectrometer. They typically have a charge of tens of pC, an energy spread of a few GeV, and a maximum energy of up to 30 GeV. The emittance of this group of electrons can be many times smaller than the initial emittance of the drive beam. The energy scaling for the trapped charge from one plasma length to the other is consistent with the blowout theory of the plasma wakefield.

  4. Research on the mechanisms of EME and charge accumulation during the rock crush

    Institute of Scientific and Technical Information of China (English)

    SU Wei-jia; LI Yan-ming

    2008-01-01

    The phenomenon of EME and charge accumulation were included during the load-bearing failure processing of the rock. The mechanism and signal law of the two kinds of phenomenon through the experiment, as well as the mutual relation of the two kinds of phenomenon, were contribute to monitor the regulation of the mine rock and prevent the dynamic disasters of the mine. There were two charge sensors, one electromagnetic radiated sensors and one pressure sensor in the experiment to detect the EME signal and the charge intensity signal during the load-bearing failure processing of the rock.The results show that the charge intensity signal is prior to the EME signal through the date processing and numerical analysis. The two signals change obviously before the rock crush. The two kinds of phenomenon are homogenous and have obvious master-slave characteristic. With the appeared of the EME signal, the charge intensity signal decreased,the power is released.

  5. Explorative Study of SQL Injection Attacks and Mechanisms to Secure Web Application Database- A Review

    Directory of Open Access Journals (Sweden)

    Chandershekhar Sharma

    2016-03-01

    Full Text Available The increasing innovations in web development technologies direct the augmentation of user friendly web applications. With activities like - online banking, shopping, booking, trading etc. these applications have become an integral part of everyone’s daily routine. The profit driven online business industry has also acknowledged this growth because a thriving application provides the global platform to an organization. Database of web application is the most valuable asset which stores sensitive information of an individual and of an organization. SQLIA is the topmost threat as it targets the database on web application. It allows the attacker to gain control over the application ensuing financial fraud, leak of confidential data and even deleting the database. The exhaustive survey of SQL injection attacks presented in this paper is based on empirical analysis. This comprises the deployment of injection mechanism for each attack with respective types on various websites, dummy databases and web applications. The paramount security mechanism for web application database is also discussed to mitigate SQL injection attacks.

  6. Mechanism of H-mode triggering by CT injection in the STOR-M tokamak

    International Nuclear Information System (INIS)

    The H-mode like discharges induced by tangential compact torus (CT) injection in the STOR-M tokamak and by other techniques, such as by a short current pulse and electrode/limiter biasing, are commonly characterized by an increase in the electron density, significant reduction in the Hα radiation level, and steepening of the edge density profile. The H-modes induced by negative biasing and edge heating via a short current pulse result in large negative electric potential biasing, formation of a strong poloidal velocity shear, and slowdown of the toroidal flow. In contrast, in the H-modes induced by positive biasing and CT injection, only moderate positive electric potential biasing occurs. Formation of a strong poloidal velocity shear is absent, but the toroidal flow velocity increases. A plausible mechanism that does not require strong velocity shear itself to suppress the long wavelength turbulence is attributed to the stabilizing role of the curvature in the toroidal velocity profile. (author)

  7. Oxidation and metal-insertion in molybdenite surfaces: evaluation of charge-transfer mechanisms and dynamics

    OpenAIRE

    Shutthanandan V; Becker U; Ramana CV; Julien CM

    2008-01-01

    Abstract Molybdenum disulfide (MoS2), a layered transition-metal dichalcogenide, has been of special importance to the research community of geochemistry, materials and environmental chemistry, and geotechnical engineering. Understanding the oxidation behavior and charge-transfer mechanisms in MoS2 is important to gain better insight into the degradation of this mineral in the environment. In addition, understanding the insertion of metals into molybdenite and evaluation of charge-transfer me...

  8. On the Mechanism of the Primary Charge Separation in Bacterial Photosynthesis

    CERN Document Server

    Mak, C H; Egger, Reinhold

    1994-01-01

    We present a detailed analysis of the mechanism of the primary charge separation process in bacterial photosynthesis using real-time path integrals. Direct computer simulations as well as an approximate analytical theory have been employed to map out the dynamics of the charge separation process in many regions of the parameter space relevant to bacterial photosynthesis. Two distinct parameter regions, one characteristic of sequential transfer and the other characteristic of superexchange, have been found to yield charge separation dynamics in agreement with experiments. Nonadiabatic theory provides accurate rate estimates for low-lying and very high-lying bacteriochlorophyll state energies, but it breaks down in between these two regimes.

  9. Application of charge-injection devices for digital X-ray imaging using a planar gas-type X-ray detector

    Science.gov (United States)

    Oh, K.; Shin, J.; Yun, M.; Park, H.; Park, J.; Nam, S.

    2012-07-01

    We have developed a planar gas-type detector, based on a charge injection device; this device can be used for digital X-ray imaging. Previously, in order to obtain X-ray images, a planar gas-type detector utilized a line-scanning module based on a one-dimensional readout system; however, that technology suffered from a limitation such as a long readout time, not suitable for a fluoroscopy or a moving imaging acquisition. In this study, a readout module based on charge-injection devices was used in conjunction with the planar gas-type detector to acquire signals and two-dimensional digital images. In the original design, two orthogonally cross-shaped top electrodes, called X address and Y address, played important roles in transferring and collecting the generated charges using electrical potential. During the optimization process, the shape of these top electrodes was modified into a honeycomb shape to increase the efficacy of charge collection. A mixture of gas and dielectric layers were selected to make an efficient gas-type detector for digital X-ray imaging. From the result, the electrical properties of the detector were investigated and the effectiveness of its geometrical design was proved. Measurements demonstrated the linearity of X-ray detection, and the successful movement and collection of charge using electrical potential. Thus, this modified planar gas-type detector and charge readout module using a charge-injection device made it possible to obtain two-dimensional images without using a scanning mode.

  10. Charge transfer and transport in DNA

    OpenAIRE

    Jortner, Joshua; Bixon, Mordechai; Langenbacher, Thomas; Michel-Beyerle, Maria E.

    1998-01-01

    We explore charge migration in DNA, advancing two distinct mechanisms of charge separation in a donor (d)–bridge ({Bj})–acceptor (a) system, where {Bj} = B1,B2, … , BN are the N-specific adjacent bases of B-DNA: (i) two-center unistep superexchange induced charge transfer, d*{Bj}a → d∓{Bj}a±, and (ii) multistep charge transport involves charge injection from d* (or d+) to {Bj}, charge hopping within {Bj}, and charge trapping by a. For off-resonance coupling, mechanism i prevails with the char...

  11. MORPHOLOGY AND MECHANICAL PROPERTIES OF POLY(ETHYLENE-OCTENE) COPOLYMERS OBTAINED BY DYNAMIC PACKING INJECTION MOLDING

    Institute of Scientific and Technical Information of China (English)

    Dong Liang; Li-juan Zhou; Qin Zhang; Feng Chen; Ke Wang; Hua Deng; Qiang Fu

    2012-01-01

    The morphology and mechanical properties of poly(ethylene-octene) copolymers (POE) obtained by dynamic packing injection molding were investigated by mechanical tests,differential scanning calorimetry (DSC),fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM).The mechanical tests found that only POE with low octene content and high molecular weight show apparent response for external shear field.Further investigation has been done by DSC,FT-IR,and SEM in order to make clear the reason of that phenomenon.Finally,the hypothetical mechanism of POE microstructure formation under shear field has been proposed.For POE with low octene content and high molecular weight,orientation degree and mechanical properties both increase substantially under shear field.For POE with low octene content and low molecular weight,orientation degree and crystallinity increase under shear field,but it is not dramatically benefit for the mechanical properties.For POE with high octene content and high molecular weight,the shear field has little effect on the morphology and mechanical properties.

  12. Analysis method and utilization mechanism of the overall value of EV charging

    International Nuclear Information System (INIS)

    Highlights: • Analysis on the overall value of EV charging from a viewpoint of system. • An analytical model of the overall value of EV charging was presented. • A model was proposed to calculate the value of emission reduction by EV. • A model to evaluate the improvement in new energy utilization was given. • A utilization mechanism apt to overall optimization was proposed. - Abstract: Electric Vehicle (EV) can save energy while reducing emissions and has thus attracted the attention of both academics and industry. The cost and benefit of charging are one of the key issues in relation to EV development that has been researched extensively. But many studies are carried out from a viewpoint of some local entities rather than a global system, focus on specific types or aspects of EV charging, or use mixed models that can only be computed by computer simulation and lack physical transparency. This paper illuminated that it is necessary to consider the value of EV charging on a system scale. In order to achieve this, it presents an analytical model for analyzing the overall value of EVs, an analysis model to evaluate the reduction of pollutions relevant to photovoltaic power, and a model to transfer the intrinsic savings of wind power to the off-peak charging loads. It is estimated that EV charging has a significant positive value, providing the basis for enhanced EV subsidies. Accordingly, a utilization mechanism apt to optimize globally is proposed, upon which sustainable business models can be formed by providing adequate support, including the implementation of a peak–valley tariff, charging subsidies and one-time battery subsidies. This utilization mechanism, by taking full advantage of the operation system of power utilities to provide basic support and service, may provide new approaches to the development of EVs. The method proposed here is of important value for the systematic considerations about EV development and maybe can help broaden the

  13. Charging/discharging behavior and mechanism of silicon quantum dots embedded in amorphous silicon carbide films

    International Nuclear Information System (INIS)

    The charging/discharging behavior of Si quantum dots (QDs) embedded in amorphous silicon carbide (a-SiCx) was investigated based on the Al/insulating layer/Si QDs embedded in a-SiCx/SiO2/p-Si (metal-insulator-quantum dots-oxide-silicon) multilayer structure by capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. Transmission electron microscopy and Raman scattering spectroscopy measurements reveal the microstructure and distribution of Si QDs. The occurrence and shift of conductance peaks indicate the carrier transfer and the charging/discharging behavior of Si QDs. The multilayer structure shows a large memory window of 5.2 eV at ±8 V sweeping voltage. Analysis of the C-V and G-V results allows a quantification of the Coulomb charging energy and the trapped charge density associated with the charging/discharging behavior. It is found that the memory window is related to the size effect, and Si QDs with large size or low Coulomb charging energy can trap two or more electrons by changing the charging voltage. Meanwhile, the estimated lower potential barrier height between Si QD and a-SiCx, and the lower Coulomb charging energy of Si QDs could enhance the charging and discharging effect of Si QDs and lead to an enlarged memory window. Further studies of the charging/discharging mechanism of Si QDs embedded in a-SiCx can promote the application of Si QDs in low-power consumption semiconductor memory devices

  14. Charging/discharging behavior and mechanism of silicon quantum dots embedded in amorphous silicon carbide films

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Xixing; Zeng, Xiangbin, E-mail: eexbzeng@163.com; Zheng, Wenjun; Liao, Wugang [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Feng, Feng [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Shenzhen Institute of Huazhong University of Science and Technology, Shenzhen 518000 (China)

    2015-01-14

    The charging/discharging behavior of Si quantum dots (QDs) embedded in amorphous silicon carbide (a-SiC{sub x}) was investigated based on the Al/insulating layer/Si QDs embedded in a-SiC{sub x}/SiO{sub 2}/p-Si (metal-insulator-quantum dots-oxide-silicon) multilayer structure by capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. Transmission electron microscopy and Raman scattering spectroscopy measurements reveal the microstructure and distribution of Si QDs. The occurrence and shift of conductance peaks indicate the carrier transfer and the charging/discharging behavior of Si QDs. The multilayer structure shows a large memory window of 5.2 eV at ±8 V sweeping voltage. Analysis of the C-V and G-V results allows a quantification of the Coulomb charging energy and the trapped charge density associated with the charging/discharging behavior. It is found that the memory window is related to the size effect, and Si QDs with large size or low Coulomb charging energy can trap two or more electrons by changing the charging voltage. Meanwhile, the estimated lower potential barrier height between Si QD and a-SiC{sub x}, and the lower Coulomb charging energy of Si QDs could enhance the charging and discharging effect of Si QDs and lead to an enlarged memory window. Further studies of the charging/discharging mechanism of Si QDs embedded in a-SiC{sub x} can promote the application of Si QDs in low-power consumption semiconductor memory devices.

  15. Charging/discharging behavior and mechanism of silicon quantum dots embedded in amorphous silicon carbide films

    Science.gov (United States)

    Wen, Xixing; Zeng, Xiangbin; Zheng, Wenjun; Liao, Wugang; Feng, Feng

    2015-01-01

    The charging/discharging behavior of Si quantum dots (QDs) embedded in amorphous silicon carbide (a-SiCx) was investigated based on the Al/insulating layer/Si QDs embedded in a-SiCx/SiO2/p-Si (metal-insulator-quantum dots-oxide-silicon) multilayer structure by capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. Transmission electron microscopy and Raman scattering spectroscopy measurements reveal the microstructure and distribution of Si QDs. The occurrence and shift of conductance peaks indicate the carrier transfer and the charging/discharging behavior of Si QDs. The multilayer structure shows a large memory window of 5.2 eV at ±8 V sweeping voltage. Analysis of the C-V and G-V results allows a quantification of the Coulomb charging energy and the trapped charge density associated with the charging/discharging behavior. It is found that the memory window is related to the size effect, and Si QDs with large size or low Coulomb charging energy can trap two or more electrons by changing the charging voltage. Meanwhile, the estimated lower potential barrier height between Si QD and a-SiCx, and the lower Coulomb charging energy of Si QDs could enhance the charging and discharging effect of Si QDs and lead to an enlarged memory window. Further studies of the charging/discharging mechanism of Si QDs embedded in a-SiCx can promote the application of Si QDs in low-power consumption semiconductor memory devices.

  16. Constant Rate or Stepwise Injection of Cold Fluid into a Geologic Formation: A Hydro-Thermo-Mechanical Analysis

    Science.gov (United States)

    Kim, S.; Hosseini, S. A.

    2015-12-01

    Operations such as CO2 geologic storage, enhanced geothermal systems, and wastewater injection are rendering fluid injection as important as fluid extraction. In particular, injecting fluid colder than the original fluid causes thermal contraction and ensuing decreases in stresses, which yield an effect opposite of what volume expansion driven by the fluid injection imposes. In this study, we conduct numerical simulations to investigate pore-pressure buildup, thermal diffusion, and stress changes for two conditions: (1) constant rate, and (2) stepwise injection of cold fluid. The numerical-simulation method—which combines fluid flow, poroelasticity, thermal diffusion, and thermal stress—is based on the single-phase flow condition to simplify a computation model and thus facilitate a focus on mechanical responses. We also examine temporal evolutions of stress states and mobilized friction angles across base, injection-zone, and caprock layers for two different stress regimes: normal-faulting and reverse-faulting. Under the normal-faulting stress regime, the maximum mobilized friction angle occurs inside of the injection zone, which may act to improve the stability of the caprock. Special attention is required, however, because the location of the maximum mobilized friction angle is close to interfaces with the caprock and base layers. The hypothetical stepwise injection of cold fluid is shown to improve the stability of the injection zone to some extent. Under the reverse-faulting stress regime, the maximum mobilized friction angle occurs near the middle of the injection zone; stability in the injection zone is enhanced while that in the caprock/base is aggravated with time. The hypothetical stepwise injection not only helps improve the stability of the injection zone but also delays the moment when the maximum friction angle is mobilized. Finally, we suggest using dimensionless parameters to determine a prevalence of the thermal-stress effect in the injection

  17. Simulating Thermal-Hydrologic-Mechanical-Chemical Evolution Surrounding Fluid Injection in a Fractured Porous Geothermal Reservoir

    Science.gov (United States)

    Taron, J.; Min, K.; Elsworth, D.

    2006-12-01

    Computational analysis is conducted on the coupled thermal-hydrologic-mechanical-chemical (THMC) behavior of a stimulated EGS geothermal reservoir. Numerical analyses utilize a newly developed simulator capable of examining THMC processes in fractured porous geologic media. The simulator links the thermal-hydrologic- chemical (THC) computational code TOUGHREACT with the mechanical (M) capability of FLAC3D, where the response of pore fluid pressure to mechanical disturbance is treated as an undrained system and mineral precipitation/dissolution generates porosity and permeability change within each dual-permeability continuum. Non-linear permeability response to thermal-hydrologic-mechanical (THM) mechanisms is accommodated via embryonic mechanical and transport constitutive laws, and is considered to act in union with permeability changes associated with the removal or addition of minerals within the system. This construct is applied to the geometry of an injector-withdrawal doublet within the Coso Geothermal field, where in situ stress conditions, thermal state, and mineralogical composition at 3000m depth are extracted from recorded field data. Initial results for feasible parametric settings show that permeability reduction in the vicinity of a cool (80°C) injection well may be significant, within an order of magnitude, and accompanied by large (MPa) changes in the stress field throughout the reservoir for imposed boundary conditions of constant stress.

  18. A Method for Compensating Customer Voltage Drops due to Nighttime Simultaneous Charging of EVs Utilizing Reactive Power Injection from Battery Chargers

    Science.gov (United States)

    Noda, Taku; Kabasawa, Yuichiro; Fukushima, Kentaro; Nemoto, Koshichi; Uemura, Satoshi

    When we consider the global warming, the reduction of CO2 emission is one of the most important problems which require urgent solutions. One option is to integrate low-CO2-emission generators to the grid as much as possible. Another option is to replace inefficient vehicles based on internal-combustion engines with electric ones (EVs). Due to the latter, we can easily estimate that most consumers will charge EVs' batteries at nighttime. Thus, excessive voltage drops due to the nighttime simultaneous charging are supposed to be a possible future problem. This paper proposes a method for compensating the voltage drops by injecting reactive power from EV battery chargers.

  19. [Study on action mechanism of Danhong injection based on computational system biology approach].

    Science.gov (United States)

    Lv, Yan-ni; Wei, Xiao-hua; Xiao, Pin

    2015-02-01

    Danhong injection is a compound preparation of traditional Chinese medicine Salvia miltiorrhiza and Carthamus tinctorius, and has been widely applied in treating coronary heart diseases and ischemic encephalopathy in clinic. Despite the complexity of its chemical compounds and the diversity of targets, especially in system biology, there have not a report for its action mechanism as a whole regulatory biological network. In this study, protein data of S. miltiorrhiza and C. tinctorius were searched in TCMGeneDIT database and agilent literature search (ALS) system to establish the multi-component protein network of S. miltiorrhiza, C. tinctorius and Danhong injection. Besides, the protein interaction network was built based on the protein-protein interaction in Genecards, BIND, BioGRID, IntAct, MINT and other databases. According to the findings, 10 compounds of S. miltiorrhiza and 14 compounds of C. tinctorius were correlated with proteins. The 24 common compounds had interactions with 81 proteins, and formed a protein interaction network with 60 none-isolated nodes. The Cluster ONE module was applied to make an enrichment analysis on the protein interaction network and extract one sub-network with significant difference P <0.05. The sub-network contains 23 key proteins, which involved five signaling pathways, namely Nod-like receptor signaling pathway, epithelial cell signaling in helicobacter pylori infection, Toll-like receptor signaling pathway, RIG-I-like receptor signaling pathway and neurotrophin signaling pathway through KEGG signaling pathway mapping. In this study, the computational system biology approach was adopted to preliminarily explain the molecular mechanism of main compounds of Danhong injection in preventing and treating diseases and provide reference for systematic studies on traditional Chinese medicine compounds. PMID:26084184

  20. Characterization of surface charge and mechanical properties of chitosan/alginate based biomaterials

    International Nuclear Information System (INIS)

    This study aims to examine mechanical properties and surface charge characteristics of chitosan/alginate-based films for biomedical applications. By varying the concentrations of chitosan and alginate, we have developed films with varying surface charge densities and mechanical characteristics. The surface charge densities of these films were determined by applying an analytical model on force curves derived from an atomic force microscope (AFM). The average surface charge densities of films containing 60% chitosan and 80% chitosan were found to be - 0.46 mC/m2 and - 0.32 mC/m2, respectively. The surface charge density of 90% chitosan containing films was found to be neutral. The elastic moduli and the water content were found to be decreasing with increasing chitosan concentration. The films with 60%, 80% and 90% chitosan gained 93.5 ± 6.6%, 217.1 ± 22.1% and 396.8 ± 67.5% of their initial weight, respectively. Their elastic moduli were found to be 2.6 ± 0.14 MPa, 1.9 ± 0.27 MPa and 0.93 ± 0.12 MPa, respectively. The trend observed in the mechanical response of these films has been attributed to the combined effect of the concentration of polyelectrolyte complexes (PEC) and the amount of water absorbed. The Fourier transform infrared spectroscopy experiments indicate the presence of higher alginate on the surface of the films compared to the bulk in all films. The presence of higher alginate on surface is consistent with negative surface charge densities of these films, determined from AFM experiments. Highlights: → Chitosan/alginate based fibrous polyelectrolyte complex films were developed. → The average surface charge density of the films was determined using AFM. → Elastic modulus of the films increased with increase in PEC content. → FTIR analysis indicated higher alginate content on surface compared to bulk.

  1. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Alghamdi, H., E-mail: haalghamdi@nu.edu.sa [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Faculty of Engineering, Najran University, Najran, P.O.Box 1988 (Saudi Arabia); Chen, G.; Vaughan, A. S. [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2015-12-15

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  2. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    International Nuclear Information System (INIS)

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology

  3. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Science.gov (United States)

    Alghamdi, H.; Chen, G.; Vaughan, A. S.

    2015-12-01

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  4. Relationship between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites

    Energy Technology Data Exchange (ETDEWEB)

    Reis, R.L.; Cunha, A.M.; Oliveira, M.J.; Campos, A.R. [Dept. of Polymer Engineering, University of Minho, Guimaraes (Portugal); Bevis, M.J. [Wolfson Center for Materials Processing, Brunel Univ., Uxbridge (United Kingdom)

    2001-04-01

    We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by conventional injection molding and by Scorim (shear controlled orientation in injection molding) under a wide range of processing windows. Tensile testing is performed and the corresponding performance related to the morphology evaluated by polarized light microscopy and scanning electron microscopy. The control of the processing parameters led to significant improvements of the tensile properties. Compounding by TSE and then processing by Scorim produces the maximum modulus of 7.4 GPa and the ductility as high as 19%, for the HA weight fraction of 30%. These mechanical properties match those of bone, and were obtained with much smaller amounts of HA reinforcement then has been previously reported in literature. Our PE + HA composites present the additional benefit of being ductile even for 50% HA amounts. The use Scorim is a unique way of inducing anisotropy to thick sections and to produce very stiff composites that may be used in biomedical applications with important mechanical loads. This fact, combined with the bioactive behavior of the HA phase, makes our composite usable for orthopedic load-bearing implants. (orig.)

  5. Controlling Mechanism and Resulting Spray Characteristics of Injection of Fuel Containing Dissolved Gas

    Institute of Scientific and Technical Information of China (English)

    HuangZhen; ShaoYiming; 等

    1994-01-01

    This paperpresents a recent advance in the study of injection of fuel containing dissolved gas(IFCDG).Using diesel fuel containing dissolved CO2,experiments were performed under atmospheric conditions on a diesel hole-type nozzle and simple nozzles.The effects of gas concentration in the fuel,injection pressure and the nozzle L/D ratio were examined.In order to reveal the controlling mechanism of IFCDG,the orifice flow pattern,pressure characteristics and their effects were also investigated.The result shows that IFCDG can produce a parabolic-shaped spray pattern with good atomization,which suggests the existence of a new atomization mechanism,In terms of atomization,the beneficial effect of the IFCDG is obtained at the dissolved gas concentration above the transition and in the region of larger nozzle L/D ratio.However,under unfavorable conditions,IFCDG will lead to deterioration of atomization with coarse fuel droplets.It is found that the big difference of the orifice pressure characteristics caused by the variation of the nozzle L/D ratio has a dominant influence on the separation of the dissolved gas from the fuel inside the orifice and is verified to account for a dramatic change in the spray pattern and determine the effect of IFCDG.It is considered that the concept of IFCDG could be attrative in producing more efficient,clean engine and find use in a wide range of application.

  6. Physical and Mechanical Properties of Injected Granular Soil with Thick Super Plasticized Grouts

    Directory of Open Access Journals (Sweden)

    Costas A. Anagnostopoulos

    2015-06-01

    Full Text Available The use of super-plasticizers in micro fine or regular cement-based grouts has become of vital importance in advanced professional grouting practices. These super-plasticizers play an important role in the production of more durable grouts with improved rheological characteristics. This report presents a laboratory study of the effect of a new-generation Polycarboxylate Super-plasticizer (PCE on the inject ability of thick cement grouts into a coarse soil, under different grouting pressures, in comparison to that of a polynaphthalene (SNF super-plasticizer. Finally, the physical (dry unit weight, porosity and permeability and mechanical properties (compressive strength, elastic modulus of grouted specimens with various grouts were examined. The experiments were conducted using different additive dosages with grouts proportioned with a water to cement ratio (w/c of 0.33, 0.4 and 0.5, respectively. The results showed that PCE super-plasticizer is more effective than the SNF one for the increase of grout inject ability and the improvement of physical and mechanical properties of grouted soil.

  7. Charge distribution in scattering off nuclei: A test of the production mechanism

    International Nuclear Information System (INIS)

    In the dual parton model, the absolute value of the charge in the forward hemisphere in collisions of negative particles with nucleons increases with energy. This effect is strongly amplified in collisions with nuclei when the number of struck nucleons increases. It can provide a crucial test of the particle production mechanism. (orig.)

  8. Mechanism and Dynamics of Charge Transfer in Donor-Bridge-Acceptor Systems

    NARCIS (Netherlands)

    Gorczak-Vos, N.

    2016-01-01

    Photoinduced charge transfer in organic materials is a fundamental process in various biological and technological areas. Donor-bridge-acceptor (DBA) molecules are used as model systems in numerous theoretical and experimental work to systematically study and unravel the underlying mechanisms of cha

  9. Mechanisms for the sputtering of condensed-gas solids by charged particles

    International Nuclear Information System (INIS)

    The relationship of sputtering and luminescence data is examined and some aspects of the electronic relaxation process are discussed. Molecular mechanisms of the relaxation process leading to the dissociation or the production of an atomic or molecular species having appreciable kinetic energy are considered in detail. The role of these mechanisms in charged particle sputtering of insulating materials, especially condensed-gas solids and organic solids, is described

  10. Fouling control mechanisms of demineralized water backwash: Reduction of charge screening and calcium bridging effects

    KAUST Repository

    Li, Sheng

    2011-12-01

    This paper investigates the impact of the ionic environment on the charge of colloidal natural organic matter (NOM) and ultrafiltration (UF) membranes (charge screening effect) and the calcium adsorption/bridging on new and fouled membranes (calcium bridging effect) by measuring the zeta potentials of membranes and colloidal NOM. Fouling experiments were conducted with natural water to determine whether the reduction of the charge screening effect and/or calcium bridging effect by backwashing with demineralized water can explain the observed reduction in fouling. Results show that the charge of both membranes and NOM, as measured by the zeta potential, became more negative at a lower pH and a lower concentration of electrolytes, in particular, divalent electrolytes. In addition, calcium also adsorbed onto the membranes, and consequently bridged colloidal NOM and membranes via binding with functional groups. The charge screening effect could be eliminated by flushing NOM and membranes with demineralized water, since a cation-free environment was established. However, only a limited amount of the calcium bridging connection was removed with demineralized water backwashes, so the calcium bridging effect mostly could not be eliminated. As demineralized water backwash was found to be effective in fouling control, it can be concluded that the reduction of the charge screening is the dominant mechanism for this. © 2011 Elsevier Ltd.

  11. Evolution of ring current formed by relativistic electron beam injection into a charge but not current neutralizing plasma

    International Nuclear Information System (INIS)

    The time evolutions of the azimuthal momentum distribution of the axisymmetrically injected electrons and the resulting ring current are self-consistently analyzed under the assumption that no return current is induced in the background plasma. It is shown that the ring current grows linearly with time for a characteristic time from the start of beam injection, and afterthere it tends to saturate at some level. The dependence of the time evolution of the ring current on the beam energy at injection and on the injection current is also obtained. (author)

  12. Characterization of an injectable, degradable polymer for mechanical stabilization of mandibular fractures.

    Science.gov (United States)

    Henslee, Allan M; Yoon, Diana M; Lu, Benjamin Y; Yu, Joseph; Arango, Andrew A; Marruffo, Liann P; Seng, Luke; Anver, Tamir D; Ather, Hunaiza; Nair, Manitha B; Piper, Sean O; Demian, Nagi; Wong, Mark E K; Kasper, F Kurtis; Mikos, Antonios G

    2015-04-01

    This study investigated the use of injectable poly(propylene fumarate) (PPF) formulations for mandibular fracture stabilization applications. A full factorial design with main effects analysis was employed to evaluate the effects of the PPF:N-vinyl pyrrolidone (NVP, crosslinking agent) ratio and dimethyl toluidine (DMT, accelerator) concentration on key physicochemical properties including setting time, maximum temperature, mechanical properties, sol fraction, and swelling ratio. Additionally, the effects of formulation crosslinking time on the mechanical and swelling properties were investigated. The results showed that increasing the PPF:NVP ratio from 3:1 to 4:1 or decreasing the DMT concentration from 0.05 to 0.01 v/w % significantly decreased all mechanical properties as well as significantly increased the sol fraction and swelling ratio. Also, increasing the crosslinking time at 37°C from 1 to 7 days significantly increased all mechanical properties and decreased both the sol fraction and swelling ratio. This study further showed that the flexural stiffness of ex vivo stabilized rabbit mandibles increased from 1.7 ± 0.3 N/mm with a traditional mini-plate fixator to 14.5 ± 4.1 N/mm for the 4:1 (0.05 v/w % DMT) PPF formulation at day 1. Overall, the formulations tested in this study were found to have properties suitable for potential further consideration in mandibular fracture fixation applications. PMID:24934595

  13. The absence of a dense potential core in supercritical injection: A thermal break-up mechanism

    Science.gov (United States)

    Banuti, Daniel T.; Hannemann, Klaus

    2016-03-01

    Certain experiments in quasi-isobaric supercritical injection remain unexplained by the current state of theory: Without developing a constant value potential core as expected from the mechanical view of break-up, density is observed to drop immediately upon entering the chamber. Furthermore, this phenomenon has never been captured in computational fluid dynamics (CFD) despite having become a de facto standard case for real fluid CFD validation. In this paper, we present strong evidence for a thermal jet disintegration mechanism (in addition to classical mechanical break-up) which resolves both the theoretical and the computational discrepancies. A new interpretation of supercritical jet disintegration is introduced, based on pseudo-boiling, a nonlinear supercritical transition from gas-like to liquid-like states. We show that thermal disintegration may dominate classical mechanical break-up when heat transfer takes place in the injector and when the fluid state is sufficiently close to the pseudo-boiling point. A procedure which allows to capture subsided cores with standard CFD is provided and demonstrated.

  14. Contrast mechanism due to interface trapped charges for a buried SiO2 microstructure in scanning electron microscopy.

    Science.gov (United States)

    Zhang, Hai-Bo; Li, Wei-Qin; Wu, Dan-Wei

    2009-01-01

    We clarify the scanning electron microscopic contrast mechanism for imaging a buried SiO(2) trench microstructure with interface trapped charges by simulating both electron scattering and transport. Here, the interface trapped charges make the SiO(2) film more negatively charged and increase excess holes in the space charge distribution of the electron scattering region. The generated positive surface electric field thus redistributes some emitted secondary electrons and results in the dark contrast. This contrast mechanism is validated by comparing with experiments, and it may also provide an interesting approach for imaging and detecting deep interface trapped charges in insulating films. PMID:19029106

  15. Elastin based cell-laden injectable hydrogels with tunable gelation, mechanical and biodegradation properties.

    Science.gov (United States)

    Fathi, Ali; Mithieux, Suzanne M; Wei, Hua; Chrzanowski, Wojciech; Valtchev, Peter; Weiss, Anthony S; Dehghani, Fariba

    2014-07-01

    Injectable hydrogels made from extracellular matrix proteins such as elastin show great promise for various biomedical applications. Use of cytotoxic reagents, fixed gelling behavior, and lack of mechanical strength in these hydrogels are the main associated drawbacks. The aim of this study was to develop highly cytocompatible and injectable elastin-based hydrogels with alterable gelation characteristics, favorable mechanical properties and structural stability for load bearing applications. A thermoresponsive copolymer, poly(N-isopropylacrylamide-co-polylactide-2-hydroxyethyl methacrylate-co-oligo(ethylene glycol)monomethyl ether methacrylate, was functionalized with succinimide ester groups by incorporating N-acryloxysuccinimide monomer. These ester groups were exploited to covalently bond this polymer, denoted as PNPHO, to different proteins with primary amine groups such as α-elastin in aqueous media. The incorporation of elastin through covalent bond formation with PNPHO promotes the structural stability, mechanical properties and live cell proliferation within the structure of hydrogels. Our results demonstrated that elastin-co-PNPHO solutions were injectable through fine gauge needles and converted to hydrogels in situ at 37 °C in the absence of any crosslinking reagent. By altering PNPHO content, the gelling time of these hydrogels can be finely tuned within the range of 2-15 min to ensure compatibility with surgical requirements. In addition, these hydrogels exhibited compression moduli in the range of 40-145 kPa, which are substantially higher than those of previously developed elastin-based hydrogels. These hydrogels were highly stable in the physiological environment with the evidence of 10 wt% mass loss in 30 days of incubation in a simulated environment. This class of hydrogels is in vivo bioabsorbable due to the gradual increase of the lower critical solution temperature of the copolymer to above 37 °C due to the cleavage of polylactide from

  16. Oxidation and Metal-Insertion in Molybdenite Surfaces: Evaluation of Charge-Transfer Mechanisms and Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ramana, Chintalapalle V.; Becker, U.; Shutthanandan, V.; Julien, C. M.

    2008-06-05

    Molybdenum sulfide (MoS2), an important representative member of the layered transition-metal dichalcogenides, has been of special importance to the research community of geochemistry, materials and environmental chemistry, and industrial science and technology. Understanding the oxidation behavior and charge-transfer mechanisms in MoS2 is important to gain better insight into the degradation of this mineral in the environment. On the other hand understanding the insertion of metals into molybdenite and evaluation of charge-transfer mechanism and dynamics is quite important to utilize these minerals in technological applications. Furthermore, such a detailed investigation of thermal oxidation behavior and intercalation process will provide a basis to further explore and model the mechanism of adsorption of metal ions on to geomedia. Therefore, the present work was performed to understand the oxidation and intercalation processes of molybdenite surfaces. The results obtained, using a wide variety of analytical techniques, are presented and discussed in this paper.

  17. Influence of stresses on the mechanical properties of charged elastomers during their aging by irradiation

    International Nuclear Information System (INIS)

    The damage in time of materials can have determining consequences on their mechanical properties. The aim of this work is to study the aging by irradiation of charged elastomers, and more particularly of charged aluminium tri-hydrated ethylene propylene diene polymers (EPDM). The evolution of this type of materials submitted to a gamma irradiation aging in presence of oxygen is presented. The materials have been tested and characterized at different aging levels, chemical, microstructural and mechanical: here only the results for small deformations and big deformations (uniaxial traction) are presented. From these analyses, it has been revealed a competition between the reticulation/chains cleavages during irradiations and the particular influence of the stresses on the mechanical properties during aging. (O.M.)

  18. Spin-injection mechanism of remagnetization and current hysteresis in magnetic junctions

    International Nuclear Information System (INIS)

    The new mechanism of the current remagnetization of the transitions with two metallic ferromagnetic layers and a thin nonmagnetic layer separating them is proposed. The spin-polarized current flows perpendicular to the ferromagnetic layers interfaces, the spins in one whereof are fixed and in the other one are free. The current leads to violation of the spin equilibrium in the free layer, which is expressed in the spin injection or extraction. The nonequilibrium spins interact with the lattice magnetization due to the s-d-exchange effective field depending on the current. Two threshold remagnetization currents, which are achieved by the current increase or decrease correspondingly are theoretically obtained, which testifies to the current hysteresis. The calculational results agree well with the experiments on the current remagnetization of the Co(I)/Cu/Co(II)-composition three-layer transitions

  19. Mechanisms of immiscible CO/sub 2/ injection in heavy oil reservoirs, Wilmington Field, CA

    Energy Technology Data Exchange (ETDEWEB)

    Spivak, A.; Chima, C.M.

    1984-04-01

    This paper describes the results of simulation studies made to investigate the mechanisms of immiscible CO/sub 2/ injection in heavy oil reservoirs. The studies were undertaken to assist in the design and monitoring of two projects implemented in the Wilmington Field, Los Angeles County, California. An equation-of-state compositional simulator was used in these studies. The equation-of-state was adjusted to match saturation pressures and swelling data from the laboratory. Simulation runs were then made to investigate the effect of various parameters on the process. The paper relates the various simulator studies to the Long Beach Oil Development Company (LBOD) project in the Tar Zone, Fault Block V and the Xtra Energy project in the Ranger Zone; Fault Block I of the Wilmington Field. Both projects use the same source of gas which is approximately 82% CO/sub 2/ and 18% N/sub 2/.

  20. Reduced Neck Muscle Strength and Altered Muscle Mechanical Properties in Cervical Dystonia Following Botulinum Neurotoxin Injections: A Prospective Study

    Directory of Open Access Journals (Sweden)

    Sirpa Mustalampi

    2016-01-01

    Full Text Available Objective To evaluate changes in the strength and mechanical properties of neck muscles and disability in patients with cervical dystonia (CD during a 12-week period following botulinum neurotoxin (BoNT injections. Methods Eight patients with CD volunteered for this prospective clinical cohort study. Patients had received BoNT injections regularly in neck muscles at three-month intervals for several years. Maximal isometric neck strength was measured by a dynamometer, and the mechanical properties of the splenius capitis were evaluated using two myotonometers. Clinical assessment was performed using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS before and at 2, 4, 8, and 12 weeks after the BoNT injections. Results Mean maximal isometric neck strength at two weeks after the BoNT injections decreased by 28% in extension, 25% in rotation of the affected side and 17% in flexion. At four weeks, muscle stiffness of the affected side decreased by 17% and tension decreased by 6%. At eight weeks, the muscle elasticity on the affected side increased by 12%. At two weeks after the BoNT injections, the TWSTRS-severity and TWSTRS-total scores decreased by 4.3 and 6.4, respectively. The strength, muscle mechanical properties and TWSTRS scores returned to baseline values at 12 weeks. Conclusions Although maximal neck strength and muscle tone decreased after BoNT injections, the disability improved. The changes observed after BoNT injections were temporary and returned to pre-injection levels within twelve weeks. Despite having a possible negative effect on function and decreasing neck strength, the BoNT injections improved the patients reported disability.

  1. Trapping of Intact, Singly-Charged, Bovine Serum Albumin Ions Injected from the Atmosphere with a 10-cm Diameter, Frequency-Adjusted Linear Quadrupole Ion Trap

    International Nuclear Information System (INIS)

    High-resolution real-time particle mass measurements have not been achievable because the enormous amount of kinetic energy imparted to the particles upon expansion into vacuum competes with and overwhelms the forces applied to the charged particles within the mass spectrometer. It is possible to reduce the kinetic energy of a collimated particulate ion beam through collisions with a buffer gas while radially constraining their motion using a quadrupole guide or trap over a limited mass range. Controlling the pressure drop of the final expansion into a quadrupole trap permits a much broader mass range at the cost of sacrificing collimation. To achieve high-resolution mass analysis of massive particulate ions, an efficient trap with a large tolerance for radial divergence of the injected ions was developed that permits trapping a large range of ions for on-demand injection into an awaiting mass analyzer. The design specifications required that frequency of the trapping potential be adjustable to cover a large mass range and the trap radius be increased to increase the tolerance to divergent ion injection. The large-radius linear quadrupole ion trap was demonstrated by trapping singly-charged bovine serum albumin ions for on-demand injection into a mass analyzer. Additionally, this work demonstrates the ability to measure an electrophoretic mobility cross section (or ion mobility) of singly-charged intact proteins in the low-pressure regime. This work represents a large step toward the goal of high-resolution analysis of intact proteins, RNA, DNA, and viruses

  2. Local mechanical properties of LFT injection molded parts: Numerical simulations versus experiments

    Science.gov (United States)

    Desplentere, F.; Soete, K.; Bonte, H.; Debrabandere, E.

    2014-05-01

    In predictive engineering for polymer processes, the proper prediction of material microstructure from known processing conditions and constituent material properties is a critical step forward properly predicting bulk properties in the finished composite. Operating within the context of long-fiber thermoplastics (LFT, length Moldflow Insight 2014 software has been used. In this software, a fiber breakage algorithm for the polymer flow inside the mold is available. Using well known micro mechanic formulas allow to combine the local fiber length with the local orientation into local mechanical properties. Different experiments were performed using a commercially available glass fiber filled compound to compare the measured data with the numerical simulation results. In this investigation, tensile tests and 3 point bending tests are considered. To characterize the fiber length distribution of the polymer melt entering the mold (necessary for the numerical simulations), air shots were performed. For those air shots, similar homogenization conditions were used as during the injection molding tests. The fiber length distribution is characterized using automated optical method on samples for which the matrix material is burned away. Using the appropriate settings for the different experiments, good predictions of the local mechanical properties are obtained.

  3. Interaction of a Magnet and a Point Charge: Unrecognized Internal Electromagnetic Momentum Eliminates the Myth of Hidden Mechanical Momentum

    CERN Document Server

    Boyer, Timothy H

    2014-01-01

    A model calculation using the Darwin Lagrangian is carried out for a magnet consisting of two current-carrying charges constrained by centripetal forces to move in a circular path in the presence of the electric field from a distant external point charge. In the limit that the magnet's two charges are non-interacting, the calculation recovers the only valid calculation for hidden mechanical momentum. However, if the magnet's charges are mutually interacting, then there is internal electromagnetic linear momentum associated with the perturbed magnet's electrostatic charge distribution and the motion of the magnet's charges. This internal electromagnetic momentum does not seem to be recognized as distinct from the familiar external electromagnetic momentum associated with the electric field of the external charge and the magnetic field of the unperturbed magnet. In the multiparticle limit, the hidden mechanical momentum becomes negligible while the internal electromagnetic momentum provides the compensating lin...

  4. Charge transport mechanisms of graphene/semiconductor Schottky barriers: A theoretical and experimental study

    International Nuclear Information System (INIS)

    Graphene has been proposed as a material for semiconductor electronic and optoelectronic devices. Understanding the charge transport mechanisms of graphene/semiconductor Schottky barriers will be crucial for future applications. Here, we report a theoretical model to describe the transport mechanisms at the interface of graphene and semiconductors based on conventional semiconductor Schottky theory and a floating Fermi level of graphene. The contact barrier heights can be estimated through this model and be close to the values obtained from the experiments, which are lower than those of the metal/semiconductor contacts. A detailed analysis reveals that the barrier heights are as the function of the interface separations and dielectric constants, and are influenced by the interfacial states of semiconductors. Our calculations show how this behavior of lowering barrier heights arises from the Fermi level shift of graphene induced by the charge transfer owing to the unique linear electronic structure

  5. Charge transport mechanisms of graphene/semiconductor Schottky barriers: A theoretical and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Haijian; Liu, Zhenghui; Xu, Gengzhao; Shi, Lin; Fan, Yingmin; Yang, Hui [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Xu, Ke, E-mail: kxu2006@sinano.ac.cn; Wang, Jianfeng; Ren, Guoqiang [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Suzhou Nanowin Science and Technology Co., Ltd., Suzhou 215123 (China)

    2014-01-07

    Graphene has been proposed as a material for semiconductor electronic and optoelectronic devices. Understanding the charge transport mechanisms of graphene/semiconductor Schottky barriers will be crucial for future applications. Here, we report a theoretical model to describe the transport mechanisms at the interface of graphene and semiconductors based on conventional semiconductor Schottky theory and a floating Fermi level of graphene. The contact barrier heights can be estimated through this model and be close to the values obtained from the experiments, which are lower than those of the metal/semiconductor contacts. A detailed analysis reveals that the barrier heights are as the function of the interface separations and dielectric constants, and are influenced by the interfacial states of semiconductors. Our calculations show how this behavior of lowering barrier heights arises from the Fermi level shift of graphene induced by the charge transfer owing to the unique linear electronic structure.

  6. Standard Practice for Measurement of Mechanical Properties During Charged-Particle Irradiation

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1996-01-01

    1.1 This practice covers the performance of mechanical tests on materials being irradiated with charged particles. These tests are designed to simulate or provide understanding of, or both, the mechanical behavior of materials during exposure to neutron irradiation. Practices are described that govern the test material, the particle beam, the experimental technique, and the damage calculations. Reference should be made to other ASTM standards, especially Practice E 521. Procedures are described that are applicable to creep and creep rupture tests made in tension and torsion test modes. 1.2 The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. The intent is to produce a correspondence between one or more aspects of the neutron and charged particle irradiations such that fundamental relationships are established between irradiation or material parameters and the material respons...

  7. Degradation of bipolar transistors under charge injection into the oxide from the backward-biased emitter p-n junction

    International Nuclear Information System (INIS)

    Results of investigating n-p-n transistors under the action of the reverse tunnel injection current are presented. The reverse volt-ampere characteristics of the emitter junction in conditions of a disconnected collector are measured at 373 K and liquid nitrogen temperature. The data obtained testify to that the radiation resistance of transistors under investigation is determined by two processes of the passivating oxide surface degradation: generation of surface states due to irradiation and reverse tunnel injection

  8. Statistical mechanical origin of the entropy of a rotating, charged black hole

    International Nuclear Information System (INIS)

    It is shown that the entropy of a rotating, charged black hole is, in senses made precise in the paper, (i) the logarithm of the number of quantum mechanically distinct ways that the hole could have been made, and (ii) the logarithm of the number of configurations that the hole's ''atmosphere,'' as measured by stationary observers, could assume in the presence of its background noise of acceleration radiation. In addition, a proof is given of the generalized second law of thermodynamics

  9. Samples of HDR Soultz Injection Microearthquakes: Mechanism Using Alternative Source Models

    Science.gov (United States)

    Jechumtalova, Z.; Sileny, J.

    2011-12-01

    offered by the seismicity induced during the massive fluid injection experiments at the Hot Dry Rock (HDR) site Soultz-sous-Forêts. The site is located in Alsace (France) within the hottest geothermal surface anomaly of the Upper Rhine Graben. From the bulk of the seismicity recorded, we have processed several microearthquakes with magnitudes between M = 1.4 and 1.5 which occurred during the first phase of 2003 fluid injection, when only the borehole GPK3 was stimulated. Mechanisms resulting from the alternative approaches offer the clue to estimate the reliability of the shear vs. non-shear source components, thus indicating the type of the fracturing.

  10. Resistivity Variation Mechanism Analysis of the Petro-Rock Injected by Water

    Institute of Scientific and Technical Information of China (English)

    WANGYinghui; TANDehui

    2005-01-01

    Many oil fields have already been coming into exploitation period in the world. Physical property,lithology and oil-bearing property, etc., have been changed after oil-reservoir flooded by water, and responses of risistivity well-logging emerge in multiplicity, various welllogging responses make interpretation of water-floodedzone more difficult. But conventional resistivity welllogging series are economical and dominated tools in many oilflelds at present, it becomes more significant to research and analyse resistivity property g~ mechanism of rock injected by water. Discuss the mechanism of ""U"" type curve,including resistivity variation features of rock, relationship of Rz (mixture liquid resistivity) and Sw (water satura-tion) in water-flooded zone. Analyse various property of the most important index n based experimental curve, and display the relationship of the index n and rn according to experimental equation. At last, discuss electric property ofwater-flooded rock theoretically. All are bases to achieve more efficient interpretation model according to conventional resistivity well-logging.

  11. Quantum mechanical investigations on the role of neutral and negatively charged enamine intermediates in organocatalyzed reactions

    International Nuclear Information System (INIS)

    Highlights: • M06-2X functional is suitable to model key steps of proline-catalyzed reactions. • Investigation of the proline-catalyzed aldol reaction mechanism. • Influence of water molecules on the C–C bond formation step. • Mechanism for the reaction of proline-derived enamines with benzhydrylium cations. - Abstract: The proline-catalyzed aldol reaction is the seminal example of asymmetric organocatalysis. Previous theoretical and experimental studies aimed at identifying its mechanism in order to rationalize the outcome of this reaction. Here, we focus on key steps with modern first principle methods, i.e. the M06-2X hybrid exchange–correlation functional combined to the solvation density model to account for environmental effects. In particular, different pathways leading to the formation of neutral and negatively charged enamine intermediates are investigated, and their reactivity towards two electrophiles, i.e. an aldehyde and a benzhydrylium cation, are compared. Regarding the self-aldol reaction, our calculations confirm that the neutral enamine intermediate is more reactive than the negatively charged one. For the reaction with benzhydrylium cations however, the negatively charged enamine intermediate is more reactive

  12. Quantum mechanical investigations on the role of neutral and negatively charged enamine intermediates in organocatalyzed reactions

    Energy Technology Data Exchange (ETDEWEB)

    Hubin, Pierre O., E-mail: pierre.hubin@unamur.be [Laboratoire de Physico-Chimie Informatique (PCI), Unité de Chimie Physique Théorique et Structurale, University of Namur, 61 rue de Bruxelles, 5000 Namur (Belgium); Jacquemin, Denis [Laboratoire CEISAM – UMR CNRS 6230, Université de Nantes, 2 rue de la Houssinière, BP92208, 44322 Nantes Cedex 3 (France); Institut Universitaire de France 103, Boulevard St Michel, 75005 Paris Cedex 5 (France); Leherte, Laurence; Vercauteren, Daniel P. [Laboratoire de Physico-Chimie Informatique (PCI), Unité de Chimie Physique Théorique et Structurale, University of Namur, 61 rue de Bruxelles, 5000 Namur (Belgium)

    2014-04-15

    Highlights: • M06-2X functional is suitable to model key steps of proline-catalyzed reactions. • Investigation of the proline-catalyzed aldol reaction mechanism. • Influence of water molecules on the C–C bond formation step. • Mechanism for the reaction of proline-derived enamines with benzhydrylium cations. - Abstract: The proline-catalyzed aldol reaction is the seminal example of asymmetric organocatalysis. Previous theoretical and experimental studies aimed at identifying its mechanism in order to rationalize the outcome of this reaction. Here, we focus on key steps with modern first principle methods, i.e. the M06-2X hybrid exchange–correlation functional combined to the solvation density model to account for environmental effects. In particular, different pathways leading to the formation of neutral and negatively charged enamine intermediates are investigated, and their reactivity towards two electrophiles, i.e. an aldehyde and a benzhydrylium cation, are compared. Regarding the self-aldol reaction, our calculations confirm that the neutral enamine intermediate is more reactive than the negatively charged one. For the reaction with benzhydrylium cations however, the negatively charged enamine intermediate is more reactive.

  13. The protective mechanism of Yisheng Injection against hepatic ischemia reperfusion injury in mice

    Institute of Scientific and Technical Information of China (English)

    Feng Cheng; You-Ping Li; Jing-Qiu Cheng; Li Feng; Sheng-Fu Li

    2004-01-01

    AIM: Hepatic ischemia/reperfusion injury may cause acute inflammatory, significant organ damage or dysfunction, and remains an important problem for liver transplantation.Our previous in vivo and in vitro studies demonstrated that Yisheng injection (YS), a traditional Chinese medicine, had protective effect on ischemia/reperfusion injury. In this study, we examined whether YS had protective effect for hepatic ischemia/reperfusion injury and explored its protective mechanism.METHODS: Hepatic warm ischemia/reperfusion was induced in mice. YS at different doses (5, 10, 20 mg/kg)was injected intraperitoneally 24 h and 1 h before ischemia and a third dose was injected intravenously just before reperfusion. The hepatocellular injury, oxidative stress,neutrophil recruitment, proinflammatory mediators and adhesion molecules associated with hepatic ischemia/reperfusion injury were assayed by enzyme-linked immunosorbent assay (ELISA), immunohistochemical assay and reverse transcription polymerase chain reaction (RT-PCR).RESULTS: Undergoing 90 min of ischemia and 6 h of reperfusion caused dramatical injuries in mouse livers.Administration of YS at doses of 5, 10 and 20 mg/kg effectively reduced serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), from 3 670±463 U/L, 2 362±323 U/L and 12 752±1 455 U/L in I/R group to 1 172±257 U/L,845±193 U/L and 2 866±427 U/L in YS (20 mg/kg) treated group, respectively (P<0.01). The liver myeloperoxidase (MPO) and malondialdehyde (MDA) contents were decreased from 1.1±0.2 (U/mg protein) and 9.1±0.7 (nmol/mg protein) in I/R group to 0.4±0.1 (U/mg protein) and 5.5±0.9 (nmol/mg protein) in YS (20 mg/kg) treated group, respectively (P<0.01). Moreover, the serum levels of tumor necrosis factor-alpha (TNF-α) were reduced from 55±9.9 (pg/mL) in I/R group to 16±4.2 (pg/mL) (P<0.01).Furthermore, the over-expressions of TNF-α and intercellular adhesion molecule-1 (ICAM-1

  14. Mechanisms of Binder Removal Involved in Supercritical Debinding of Injection Moulded Ceramics

    Science.gov (United States)

    Chartier, Thierry; Delhomme, Eric; Baumard, Jean-François

    1997-02-01

    Extraction of organic additives from extrusion-moulded ceramic parts by supercritical carbon dioxide has proved to be an efficient method for debinding [1,2]. A model of binder extraction based on diffusion equations was developed. This model was found to be in fair agreement with experimental results. Experimental kinetics of extraction of low melt point paraffins, by supercritical fluids, from injection-moulded samples are now established. A redistribution of the binder in the liquid state in the porosity of the sample, during supercritical debinding, is put in evidence. The importance of this mechanism and its influence on the validity of the model are discussed. Des études précédentes [1, 2] ont montré l'intérêt de l'extraction, à l'aide de gaz carbonique dans l'état supercritique, des additifs organiques de mise en forme de pièces céramiques. Elles ont permis de développer un modèle, établi à partir des équations de diffusion, qui est en bon accord avec les résultats expérimentaux. Les cinétiques expérimentales d'extraction, par fluide supercritique, de paraffines à bas point de fusion utilisées comme liant pour des compositions d'injection sont maintenant étudiées. Une redistribution du liant à l'état liquide au sein de la porosité de l'échantillon pendant le déliantage supercritique est mise en évidence. L'importance de ce mécanisme et son influence sur la validité du modèle sont discutées.

  15. Microstructure and mechanical behavior of metal injection molded Ti-Nb binary alloys as biomedical material.

    Science.gov (United States)

    Zhao, Dapeng; Chang, Keke; Ebel, Thomas; Qian, Ma; Willumeit, Regine; Yan, Ming; Pyczak, Florian

    2013-12-01

    The application of titanium (Ti) based biomedical materials which are widely used at present, such as commercially pure titanium (CP-Ti) and Ti-6Al-4V, are limited by the mismatch of Young's modulus between the implant and the bones, the high costs of products, and the difficulty of producing complex shapes of materials by conventional methods. Niobium (Nb) is a non-toxic element with strong β stabilizing effect in Ti alloys, which makes Ti-Nb based alloys attractive for implant application. Metal injection molding (MIM) is a cost-efficient near-net shape process. Thus, it attracts growing interest for the processing of Ti and Ti alloys as biomaterial. In this investigation, metal injection molding was applied to the fabrication of a series of Ti-Nb binary alloys with niobium content ranging from 10wt% to 22wt%, and CP-Ti for comparison. Specimens were characterized by melt extraction, optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). Titanium carbide formation was observed in all the as-sintered Ti-Nb binary alloys but not in the as-sintered CP-Ti. Selected area electron diffraction (SAED) patterns revealed that the carbides are Ti2C. It was found that with increasing niobium content from 0% to 22%, the porosity increased from about 1.6% to 5.8%, and the carbide area fraction increased from 0% to about 1.8% in the as-sintered samples. The effects of niobium content, porosity and titanium carbides on mechanical properties have been discussed. The as-sintered Ti-Nb specimens exhibited an excellent combination of high tensile strength and low Young's modulus, but relatively low ductility. PMID:23994942

  16. Numerical solution of the corona discharge problem based on mesh redefinition and test for a charge injection law

    OpenAIRE

    Khaddour, Bassem; Atten, Pierre; Coulomb, Jean-Louis

    2008-01-01

    The paper presents a numerical and experimental study of corona discharge for a blade -plate configuration. Finite element method (FEM) is used to determine the electric potential between the electrodes and charge conservation equation is solved by the method of characteristics (MOC) to determine the charge density. The structured mesh is redefined at each step of the iterative scheme, the nodes of this structured mesh being the intersection points of the field and equipotential lines. The al...

  17. Oxidation and metal-insertion in molybdenite surfaces: evaluation of charge-transfer mechanisms and dynamics

    Directory of Open Access Journals (Sweden)

    Shutthanandan V

    2008-06-01

    Full Text Available Abstract Molybdenum disulfide (MoS2, a layered transition-metal dichalcogenide, has been of special importance to the research community of geochemistry, materials and environmental chemistry, and geotechnical engineering. Understanding the oxidation behavior and charge-transfer mechanisms in MoS2 is important to gain better insight into the degradation of this mineral in the environment. In addition, understanding the insertion of metals into molybdenite and evaluation of charge-transfer mechanism and dynamics is important to utilize these minerals in technological applications. Furthermore, a detailed investigation of thermal oxidation behavior and metal-insertion will provide a basis to further explore and model the mechanism of adsorption of metal ions onto geomedia. The present work was performed to understand thermal oxidation and metal-insertion processes of molybdenite surfaces. The analysis was performed using atomic force microscopy (AFM, scanning electron microscopy (SEM, transmission electron microscopy (TEM, Rutherford backscattering spectrometry (RBS, and nuclear reaction analysis (NRA. Structural studies using SEM and TEM indicate the local-disordering of the structure as a result of charge-transfer process between the inserted lithium and the molybdenite layer. Selected area electron diffraction measurements indicate the large variations in the diffusivity of lithium confirming that the charge-transfer is different along and perpendicular to the layers in molybdenite. Thermal heating of molybenite surface in air at 400°C induces surface oxidation, which is slow during the first hour of heating and then increases significantly. The SEM results indicate that the crystals formed on the molybdenite surface as a result of thermal oxidation exhibit regular thin-elongated shape. The average size and density of the crystals on the surface is dependent on the time of annealing; smaller size and high density during the first one-hour and

  18. Oxidation and metal-insertion in molybdenite surfaces: evaluation of charge-transfer mechanisms and dynamics.

    Science.gov (United States)

    Ramana, C V; Becker, U; Shutthanandan, V; Julien, C M

    2008-01-01

    Molybdenum disulfide (MoS2), a layered transition-metal dichalcogenide, has been of special importance to the research community of geochemistry, materials and environmental chemistry, and geotechnical engineering. Understanding the oxidation behavior and charge-transfer mechanisms in MoS2 is important to gain better insight into the degradation of this mineral in the environment. In addition, understanding the insertion of metals into molybdenite and evaluation of charge-transfer mechanism and dynamics is important to utilize these minerals in technological applications. Furthermore, a detailed investigation of thermal oxidation behavior and metal-insertion will provide a basis to further explore and model the mechanism of adsorption of metal ions onto geomedia.The present work was performed to understand thermal oxidation and metal-insertion processes of molybdenite surfaces. The analysis was performed using atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA).Structural studies using SEM and TEM indicate the local-disordering of the structure as a result of charge-transfer process between the inserted lithium and the molybdenite layer. Selected area electron diffraction measurements indicate the large variations in the diffusivity of lithium confirming that the charge-transfer is different along and perpendicular to the layers in molybdenite. Thermal heating of molybenite surface in air at 400 degrees C induces surface oxidation, which is slow during the first hour of heating and then increases significantly. The SEM results indicate that the crystals formed on the molybdenite surface as a result of thermal oxidation exhibit regular thin-elongated shape. The average size and density of the crystals on the surface is dependent on the time of annealing; smaller size and high density during the first one-hour and significant

  19. Electrically charged: An effective mechanism for soft EOS supporting massive neutron star

    Science.gov (United States)

    Jing, ZhenZhen; Wen, DeHua; Zhang, XiangDong

    2015-10-01

    The massive neutron star discoverer announced that strange particles, such as hyperons should be ruled out in the neutron star core as the soft Equation of State (EOS) can-not support a massive neutron star. However, many of the nuclear theories and laboratory experiments support that at high density the strange particles will appear and the corresponding EOS of super-dense matters will become soft. This situation promotes a challenge between the astro-observation and nuclear physics. In this work, we introduce an effective mechanism to answer this challenge, that is, if a neutron star is electrically charged, a soft EOS will be equivalently stiffened and thus can support a massive neutron star. By employing a representative soft EOS, it is found that in order to obtain an evident effect on the EOS and thus increasing the maximum stellar mass by the electrostatic field, the total net charge should be in an order of 1020 C. Moreover, by comparing the results of two kind of charge distributions, it is found that even for different distributions, a similar total charge: ~ 2.3 × 1020 C is needed to support a ~ 2.0 M ⊙ neutron star.

  20. Evaluation of the film formation and the charge transport mechanism of indium tin oxide nanoparticle films

    International Nuclear Information System (INIS)

    The structure formation and charge transfer of thin nanoparticulate indium tin oxide (ITO) films prepared by dip-coating was studied as a function of stabilizer before and after annealing at different temperatures. The analysis of the film structure by optical methods revealed that it is a function of the stability. Suspensions containing an optimum stabilizer concentration of 0.1 mol/l resulted in densely packed films with a peak specific conductivity of 8.3 S cm-1 after annealing at 550 oC for 1 h in air and 121 S cm-1 after annealing in forming gas at 250 oC for 1 h, respectively. Furthermore, for the densely packed films fluctuation-induced tunnelling was found to be the dominant charge transport mechanism, whereas for the low density films a thermally activated charge transport was observed. That the films of maximum density showed a metallic charge transport behaviour at temperatures above 300 K indicated the optimal contact between ITO particles had been achieved.

  1. Increasing nuclear safety and operational reliability by upgrading the charging pump mechanical sealing system

    International Nuclear Information System (INIS)

    For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.

  2. Increasing nuclear safety and operational reliability by upgrading the charging pump mechanical sealing system

    Energy Technology Data Exchange (ETDEWEB)

    Loenhout, Gerard van [Flowserve Corporation, Etten-Leur (Netherlands); Nilsson, Peter [Flowsys Technologies AB, Moelndal (Sweden); Jehander, Magnus [Ringhals AB, Vaeroebacka (Sweden)

    2016-07-01

    For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.

  3. Increasing nuclear safety and operational reliability by upgrading the charging pump mechanical sealing system

    Energy Technology Data Exchange (ETDEWEB)

    Loenhout, Gerard van [Flowserve Corporation, Etten-Leur (Netherlands); Nilsson, Peter [Flowsys Technologies AB, Moelndal (Sweden); Jehander, Magnus [Ringhals AB, Vaeroebacka (Sweden)

    2016-03-15

    For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.

  4. Transient Fluid Flow Along Basement Faults and Rupture Mechanics: Can We Expect Injection-Induced Earthquake Behavior to Correspond Directly With Injection Operations?

    Science.gov (United States)

    Norbeck, J. H.; Horne, R. N.

    2015-12-01

    We explored injection-induced earthquake behavior in geologic settings where basement faults are connected hydraulically to overlying saline aquifers targeted for wastewater disposal. Understanding how the interaction between natural geology and injection well operations affects the behavior of injection-induced earthquake sequences has important implications for characterizing seismic hazard risk. Numerical experiments were performed to investigate the extent to which seismicity is influenced by the migration of pressure perturbations along fault zones. Two distinct behaviors were observed: a) earthquake ruptures that were confined to the pressurized region of the fault and b) sustained earthquake ruptures that propagated far beyond the pressure front. These two faulting mechanisms have important implications for assessing the manner in which seismicity can be expected respond to injection well operations.Based upon observations from the numerical experiments, we developed a criterion that can be used to classify the expected faulting behavior near wastewater disposal sites. The faulting criterion depends on the state of stress, the initial fluid pressure, the orientation of the fault, and the dynamic friction coefficient of the fault. If the initial ratio of shear to effective normal stress resolved on the fault (the prestress ratio) is less than the fault's dynamic friction coefficient, then earthquake ruptures will tend to be limited by the distance of the pressure front. In this case, parameters that affect seismic hazard assessment, like the maximum earthquake magnitude or earthquake recurrence interval, could correlate with injection well operational parameters. For example, the maximum earthquake magnitude might be expected to grow over time in a systematic manner as larger patches of the fault are exposed to significant pressure changes. In contrast, if the prestress ratio is greater than dynamic friction, a stress drop can occur outside of the pressurized

  5. Diffusion as an Oil Recovery Mechanism During CO2 Injection in Fractured Reservoirs

    OpenAIRE

    Lie, Stig Holme

    2013-01-01

    This thesis is part of an ongoing study of enhanced oil recovery by CO2 injection in the Reservoir Physics research group at the Department of Physics and Technology (IFT) at the University of Bergen. This work investigates the feasibility of oil recovery from diffusion during miscible CO2 injection in fractured core plugs by conducting appropriate laboratory tests and numerical simulations. A total of 10 miscible CO2 injection tests were conducted in the laboratory using artificially fractur...

  6. Influence of injected charges on thin Ba0.6Sr0.4TiO3 films. Electric and dielectric characterization and simulation of the charge transport

    International Nuclear Information System (INIS)

    In this study, the electric and dielectric properties of barium strontium titanate (BST) thin films were investigated by means of injected charge carriers in order to determine material properties like the field-dependent permittivity and charge carrier mobility. Starting point of this study is the band alignment of BST and tin-doped indium oxide (ITO) determined by X-Ray photoelectron spectroscopy, which reveals a negligibly small injection barrier for electrons from ITO into BST. It was shown that the resulting space charge limited currents (SCLC) cannot be fitted empirically, but need to be simulated numerically since in SCLC theory the electric field is not a constant within BST. Thus the field-dependent permittivity of BST exhibits a spatial variation. Additionally, it was pointed out that the measured current-voltage characteristics were not influenced by grain boundaries and static conditions could be applied so that for numerical simulations solely the Poisson and current density equation were necessary. On the basis of the derivative of the current-voltage characteristics in double logarithmic plot - the exponent of the voltage - the matching of measurement and simulation was possible. Three different voltage ranges were identified which could be correlated to defect states, a quasi-Fermi level dependent mobility, and a field-dependent permittivity. The basic concept for a quasi-Fermi level dependent mobility is formed by the existence of ''Urbach states'' resulting in a finite number of states within the band gap. Since their density decays exponentially with the distance from the conduction band minimum, this leads to a ''mobility edge''. Additionally, the influence of ''Urbach states'' on the charge carrier transport could be confirmed using complex nonlinear least squares fitting of impedance data.

  7. [Inhibition effect of hedyotis diffusa wild injection on HL-60 cells and its mechanism].

    Science.gov (United States)

    Chen, Xiao-Hong; Gao, Rui-Lan; Qian, Xu-Dai; Wang, Xiao; Tan, Pan-Li; Yin, Li-Ming; Zhou, Yu-Hong

    2008-10-01

    This study was aimed to explore the inhibition effect and mechanism of hedyotis diffusa wild injection (HDI) on leukemia cell line (HL-60) in vitro. The leukemia cell line HL-60 was used as target cells. The inhibitory effects of HDI on proliferation of HL-60 cells were observed by MTT assay. The positive rate of cell apoptosis and the surface marker of granulocytic differentiation (CD33 and CD15) were measured by flow cytometry. The expressions of anti-apoptosis related gene (survivin and bcl-2) were detected by RT-PCR. The results showed that the growth of HL-60 cells was inhibited by higher concentration of HDI (3.12 - 12.5 ml/L) and inhibited obviously in dose-dependent manner (p 0.05). The FCM and DNA Ladder results showed that the phenomenon of typical apoptosis did not detected after HL-60 cells were treated with the different concentrations of HDI for 24, 48 and 72 hours respectively. After HL-60 cells were treated with HDI (1.56, 3.12, 6.25 and 12.5 ml/L) for one week, the expression level of CD15 surface marker was all enhanced obviously. When treated with HDI (6.25 ml/L) for 3 weeks, the expression levels of survivin and bcl-2 gene were also decreased obviously by 60% and 44% respectively. It is concluded that HDI can inhibit HL-60 cells in the presence of its higher concentrations. The mechanisms of HDI may induce HL-60 cells differentiation, and suppress the expression of anti-apoptosis related gene (survivin or bcl-2) to inhibit the growth of HL-60 cells. PMID:18928590

  8. State of Charge Dependent Mechanical Integrity Behavior of 18650 Lithium-ion Batteries.

    Science.gov (United States)

    Xu, Jun; Liu, Binghe; Hu, Dayong

    2016-01-01

    Understanding the mechanism of mechanical deformation/stress-induced electrical failure of lithium-ion batteries (LIBs) is important in crash-safety design of power LIBs. The state of charge (SOC) of LIBs is a critical factor in their electrochemical performance; however, the influence of SOC with mechanical integrity of LIBs remains unclear. This study investigates the electrochemical failure behaviors of LIBs with various SOCs under both compression and bending loadings, underpinned by the short circuit phenomenon. Mechanical behaviors of the whole LIB body, which is regarded as an intact structure, were analyzed in terms of structure stiffness. Results showed that the mechanical behaviors of LIBs depend highly on SOC. Experimental verification on the cathode and anode sheet compression tests show that higher SOC with more lithium inserted in the anode leads to higher structure stiffness. In the bending tests, failure strain upon occurrence of short circuit has an inverse linear relationship with the SOC value. These results may shed light on the fundamental physical mechanism of mechanical integrity LIBs in relation to inherent electrochemical status. PMID:26911922

  9. A simple device to inject indicator gas for wash-out tests during mechanical ventilation

    NARCIS (Netherlands)

    I. Gultuna; P.E.M. Huygen; C. Jabaaij (C.); W.P. Holland (Wim); C. Ince (Can); H.A. Bruining (Hajo)

    1992-01-01

    textabstractObjective: To evaluate a simple device which injects a constant fraction of indicator gas to the inspiratory mixture for performing multi-breath wash-out tests during controlled ventilation. Design: the technique in which the indicator gas is injected at the mouth of the patient (post-mi

  10. Mechanical Design of the Injection Beam Line of Small Medical Cyclotron

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The injection beam line is a key device for beam transport of the small medical cyclotron, giving direct influence to the beam quality of the cyclotron. According to the medical needs of the cyclotron, the overall length of the injection beam line is as short as possible,

  11. Noise in space-charge-limited current in a CdS-single crystal at low injection level

    NARCIS (Netherlands)

    Driedonks, F.

    1967-01-01

    Current noise spectra (25Hz–20MHz) of a CdS-diode, working under space-charge-limited conditions. show trapping noise at low frequencies and slightly suppressed noise in the upper frequency range. Suppression is relatively small due to the effect of traps.

  12. Intermediate Scale Laboratory Testing to Understand Mechanisms of Capillary and Dissolution Trapping during Injection and Post-Injection of CO2 in Heterogeneous Geological Formations

    Energy Technology Data Exchange (ETDEWEB)

    Illangasekare, Tissa [Colorado School of Mines, Golden, CO (United States); Trevisan, Luca [Colorado School of Mines, Golden, CO (United States); Agartan, Elif [Colorado School of Mines, Golden, CO (United States); Mori, Hiroko [Colorado School of Mines, Golden, CO (United States); Vargas-Johnson, Javier [Colorado School of Mines, Golden, CO (United States); Gonzalez-Nicolas, Ana [Colorado School of Mines, Golden, CO (United States); Cihan, Abdullah [Colorado School of Mines, Golden, CO (United States); Birkholzer, Jens [Colorado School of Mines, Golden, CO (United States); Zhou, Quanlin [Colorado School of Mines, Golden, CO (United States)

    2015-03-31

    Carbon Capture and Storage (CCS) represents a technology aimed to reduce atmospheric loading of CO2 from power plants and heavy industries by injecting it into deep geological formations, such as saline aquifers. A number of trapping mechanisms contribute to effective and secure storage of the injected CO2 in supercritical fluid phase (scCO2) in the formation over the long term. The primary trapping mechanisms are structural, residual, dissolution and mineralization. Knowledge gaps exist on how the heterogeneity of the formation manifested at all scales from the pore to the site scales affects trapping and parameterization of contributing mechanisms in models. An experimental and modeling study was conducted to fill these knowledge gaps. Experimental investigation of fundamental processes and mechanisms in field settings is not possible as it is not feasible to fully characterize the geologic heterogeneity at all relevant scales and gathering data on migration, trapping and dissolution of scCO2. Laboratory experiments using scCO2 under ambient conditions are also not feasible as it is technically challenging and cost prohibitive to develop large, two- or three-dimensional test systems with controlled high pressures to keep the scCO2 as a liquid. Hence, an innovative approach that used surrogate fluids in place of scCO2 and formation brine in multi-scale, synthetic aquifers test systems ranging in scales from centimeter to meter scale developed used. New modeling algorithms were developed to capture the processes controlled by the formation heterogeneity, and they were tested using the data from the laboratory test systems. The results and findings are expected to contribute toward better conceptual models, future improvements to DOE numerical codes, more accurate assessment of storage capacities, and optimized placement strategies. This report presents the experimental and modeling methods

  13. Sliding-triboelectric nanogenerators based on in-plane charge-separation mechanism.

    Science.gov (United States)

    Wang, Sihong; Lin, Long; Xie, Yannan; Jing, Qingshen; Niu, Simiao; Wang, Zhong Lin

    2013-05-01

    Aiming at harvesting ambient mechanical energy for self-powered systems, triboelectric nanogenerators (TENGs) have been recently developed as a highly efficient, cost-effective and robust approach to generate electricity from mechanical movements and vibrations on the basis of the coupling between triboelectrification and electrostatic induction. However, all of the previously demonstrated TENGs are based on vertical separation of triboelectric-charged planes, which requires sophisticated device structures to ensure enough resilience for the charge separation, otherwise there is no output current. In this paper, we demonstrated a newly designed TENG based on an in-plane charge separation process using the relative sliding between two contacting surfaces. Using Polyamide 6,6 (Nylon) and polytetrafluoroethylene (PTFE) films with surface etched nanowires, the two polymers at the opposite ends of the triboelectric series, the newly invented TENG produces an open-circuit voltage up to ~1300 V and a short-circuit current density of 4.1 mA/m(2) with a peak power density of 5.3 W/m(2), which can be used as a direct power source for instantaneously driving hundreds of serially connected light-emitting diodes (LEDs). The working principle and the relationships between electrical outputs and the sliding motion are fully elaborated and systematically studied, providing a new mode of TENGs with diverse applications. Compared to the existing vertical-touching based TENGs, this planar-sliding TENG has a high efficiency, easy fabrication, and suitability for many types of mechanical triggering. Furthermore, with the relationship between the electrical output and the sliding motion being calibrated, the sliding-based TENG could potentially be used as a self-powered displacement/speed/acceleration sensor. PMID:23581714

  14. Excitation of HF and ULF-VLF waves during charged particle beams injection in active space experiment

    Czech Academy of Sciences Publication Activity Database

    Baranets, N. V.; Sobolev, Y. P.; Ruzhin, Yu. Ya.; Rothkaehl, H.; Erokhin, N. S.; Afonin, V. V.; Vojta, Jaroslav; Šmilauer, Jan

    2009-01-01

    Roč. 8, - (2009), s. 251-256. ISSN 1883-9630. [International Congress on Plasma Physics 2008/14st./. Fukuoka, 08.09.2008-12.09.2008] Institutional research plan: CEZ:AV0Z30420517 Keywords : beam-into-beam injection * waves excitation * dipole antenna Subject RIV: BL - Plasma and Gas Discharge Physics http://www.jspf.or.jp/JPFRS/PDF/Vol8/jpfrs2009_08-0251.pdf

  15. Phonon and charge fluctuation-mediated pairing mechanism in MgB2

    International Nuclear Information System (INIS)

    An effective 2D interaction is developed which incorporates screening of holes by charge density fluctuations and by optical phonons to discuss pairing mechanism. The MgB2 is treated as an ionic solid containing layers of carriers and a model dielectric function is set up which fulfills the appropriate sum rules on polarizabilities. Values of electron-phonon coupling strength and of Coulomb screening parameter indicate that MgB2 is in strong coupling regime with effective screening of carriers. Within strong coupling theory, Tc of about 43 K is estimated. Isotope exponent and pressure derivative are also estimated to be consistent with the earlier results. (author)

  16. Statistical mechanics of a one-component fluid of charged hard rods in 1D

    International Nuclear Information System (INIS)

    The statistical mechanics of a classical one component system of charged hard rods in a neutralizing background is investigated in 1D stressing on the effects of the hard core interactions over the thermodynamic and the structure of the system. The crystalline status of the system at all temperatures and densities and the absence of phase transitions is shown by extending previous results of Baxter and Kunz on the one-component plasma of point particles. Explicit expressions for the thermodynamic functions and the one-particle correlation function are given in the limits of small and strong couplings. (author)

  17. Development of Laboratory Experimental System to Clarify Solar Wind Charge Exchange Mechanism with TES Microcalorimeter

    Science.gov (United States)

    Enoki, T.; Ishisaki, Y.; Akamatsu, H.; Ezoe, Y.; Ohashi, T.; Kanda, T.; Ishida, T.; Tanuma, H.; Ohashi, H.; Shinozaki, K.; Mitsuda, K.

    2012-06-01

    Significant fraction of the cosmic diffuse soft X-ray emission (0.1-1 keV) is caused by the Solar Wind Charge eXchange (SWCX) process between the solar wind ion (C q+, N q+, O q+ etc.) and the interplanetary neutral matter. It is difficult to identify spectral features of SWCX with the spectral resolution of existing X-ray astronomy satellites. We are developing a laboratory experimental system with transition edge sensor (TES) X-ray microcalorimeters, in order to clarify the SWCX mechanism. This experiment is designed to measure Charge eXchange (CX) X-rays using Electron Cyclotron Resonance Ion Source (ECRIS) that generates multi-charged ions. Emission lines (OVIII: 2p→1s; 654 eV) by CX between O8+ and neutral He atom is aimed to be measured with energy resolution better than 10 eV. The TES microcalorimeter is cooled by a double-stage adiabatic demagnetization refrigerator (DADR), however, our TES microcalorimeter are not working potentially due to magnetic field contamination. This paper reports our experimental system, present results, and future prospects.

  18. A discussion of contributions to the 0νββ decay from the pion-charge-exchange mechanisms

    International Nuclear Information System (INIS)

    The contributions to the amplitude of the 0νββ decay, mediated by the heavy neutrino, from the two kinds of pion-charge-exchange mechanisms were discussed. The point-double-exchange mechanism is much more important for the 0 νββ decay in nuclei, compared to the point-single-exchange mechanism

  19. Influence of the injection-molding parameters on the cellular structure and thermo-mechanical properties of ethylene-propylene block copolymer foams

    OpenAIRE

    Gómez Gómez, Jaime Francisco; Arencón Osuna, David; Sánchez Soto, Miguel; Martínez Benasat, Antonio

    2013-01-01

    Microcellular injection-molding technology is capable of producing lightweight polymeric products. The foam morphology is determined by the injection-molding parameters, and it has been observed that depending on the parameter variations, the cell structure may exhibit substantial morphological differences through the entire section along the melt flow direction of the injected part. The effects of varying injection-molding parameters on foam morphology and thermal mechanical p...

  20. Thermal and mechanical properties of injection molded recycled high density polyethylene blends with virgin isotactic polypropylene

    International Nuclear Information System (INIS)

    Highlights: ► Recycled high density polyethylene and isotactic polypropylene blends have been prepared by melt compounding. ► Thermal study showed that iPP is not well dispersed into the rHDPE matrix. ► Tensile testing shows that there is strong correlation between the thermal properties and the tensile behavior of rHDPE/ipp blends. - Abstract: Polymer blending has become an important field in polymer research and especially in the area of recycling. In this research the target was to reduce the polymer waste problem. Therefore, recycled high density polyethylene (rHDPE) and virgin isotactic polypropylene (vPP) blends containing upto 30 wt% of vPP have been prepared by melt compounding method using injection molding at 220 °C. The thermal properties, thermal degradation and the mechanical properties of the polymer blends were studied using differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), and tensile testing method. DSC study shows that in all the blends there are two melting peaks, one around the melting temperature of rHDPE and another one around the melting point of vPP, indicating that vPP is not well dispersed into the rHDPE matrix. The changes in the heat of fusion for the rHDPE/iPP polymer blends versus vPP content suggests that incorporating vPP affects the crystallinity of the system. TGA analysis of the polymer blends shows that parts of rHDPE with 95/5 upto 80/20 of vPP are mostly stable composition which brings about valuable stabilization to the rHDPE. Tensile testing shows that there is strong correlation between the thermal properties and the tensile behavior of rHDPE/vpp blends

  1. Tribological and mechanical performance evaluation of metal prosthesis components manufactured via metal injection molding.

    Science.gov (United States)

    Melli, Virginia; Juszczyk, Mateusz; Sandrini, Enrico; Bolelli, Giovanni; Bonferroni, Benedetta; Lusvarghi, Luca; Cigada, Alberto; Manfredini, Tiziano; De Nardo, Luigi

    2015-01-01

    The increasing number of total joint replacements, in particular for the knee joint, has a growing impact on the healthcare system costs. New cost-saving manufacturing technologies are being explored nowadays. Metal injection molding (MIM) has already demonstrated its suitability for the production of CoCrMo alloy tibial trays, with a significant reduction in production costs, by holding both corrosion resistance and biocompatibility. In this work, mechanical and tribological properties were evaluated on tibial trays obtained via MIM and conventional investment casting. Surface hardness and wear properties were evaluated through Vickers hardness, scratch and pin on disk tests. The MIM and cast finished tibial trays were then subjected to a fatigue test campaign in order to obtain their fatigue load limit at 5 millions cycles following ISO 14879-1 directions. CoCrMo cast alloy exhibited 514 HV hardness compared to 335 HV of MIM alloy, furthermore it developed narrower scratches with a higher tendency towards microploughing than microcutting, in comparison to MIM CoCrMo. The observed fatigue limits were (1,766 ± 52) N for cast tibial trays and (1,625 ± 44) N for MIM ones. Fracture morphologies pointed out to a more brittle behavior of MIM microstructure. These aspects were attributed to the absence of a fine toughening and surface hardening carbide dispersion in MIM grains. Nevertheless, MIM tibial trays exhibited a fatigue limit far beyond the 900 N of maximum load prescribed by ISO and ASTM standards for the clinical application of these devices. PMID:25577214

  2. Nonlocal desorption of chlorobenzene molecules from the Si(111)-(7×7) surface by charge injection from the tip of a scanning tunneling microscope: remote control of atomic manipulation.

    Science.gov (United States)

    Sloan, P A; Sakulsermsuk, S; Palmer, R E

    2010-07-23

    We report the nonlocal desorption of chlorobenzene molecules from the Si(111)-(7×7) surface by charge injection from the laterally distant tip of a scanning tunneling microscope and demonstrate remote control of the manipulation process by precise selection of the atomic site for injection. Nonlocal desorption decays exponentially as a function of radial distance (decay length ∼100  A) from the injection site. Electron injection at corner-hole and faulted middle adatoms sites couples preferentially to the desorption of distant adsorbate molecules. Molecules on the faulted half of the unit cell desorb with higher probability than those on the unfaulted half. PMID:20867889

  3. Evidence of interfacial charge trapping mechanism in polyaniline/reduced graphene oxide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Rakibul; Brun, Jean-François; Roussel, Frederick, E-mail: frederick.roussel@univ-lille1.fr [University of Lille, Sciences & Technologies, Unité Matériaux et Transformations (UMET), UMR CNRS 8207, U.F.R. de Physique, P5, 59655 Villeneuve d' Ascq Cedex (France); COMUE Lille Nord de France, BP 50458-59658 Villeneuve d' Ascq Cedex (France); Papathanassiou, Anthony N. [Physics Department, Solid State Physics Section, University of Athens, Panepistimiopolis, GR15784 Zografos, Athens (Greece); Chan Yu King, Roch [Science Division, University of Science and Arts of Oklahoma, Chickasha, Oklahoma 73018 (United States)

    2015-08-03

    Relaxation mechanisms in polyaniline (PANI)/Reduced Graphene Oxide (RGO) nanocomposites are investigated using broad band dielectric spectroscopy. The multilayered nanostructural features of the composites and the intimate interactions between PANI and RGO are evidenced by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Increasing the RGO fraction in the composites results in a relaxation process observed at a frequency of ca. 5 kHz. This mechanism is associated with an electrical charge trapping phenomenon occurring at the PANI/RGO interfaces. The dielectric relaxation processes are interpreted according to the Sillars approach and the results are consistent with the presence of conducting prolate spheroids (RGO) embedded into a polymeric matrix (PANI). Dielectric permittivity data are analyzed within the framework of the Kohlrausch-William-Watts model, evidencing a Debye-like relaxation process.

  4. Charge Carrier Conduction Mechanism in PbS Quantum Dot Solar Cells: Electrochemical Impedance Spectroscopy Study.

    Science.gov (United States)

    Wang, Haowei; Wang, Yishan; He, Bo; Li, Weile; Sulaman, Muhammad; Xu, Junfeng; Yang, Shengyi; Tang, Yi; Zou, Bingsuo

    2016-07-20

    With its properties of bandgap tunability, low cost, and substrate compatibility, colloidal quantum dots (CQDs) are becoming promising materials for optoelectronic applications. Additionally, solution-processed organic, inorganic, and hybrid ligand-exchange technologies have been widely used in PbS CQDs solar cells, and currently the maximum certified power conversion efficiency of 9.9% has been reported by passivation treatment of molecular iodine. Presently, there are still some challenges, and the basic physical mechanism of charge carriers in CQDs-based solar cells is not clear. Electrochemical impedance spectroscopy is a monitoring technology for current by changing the frequency of applied alternating current voltage, and it provides an insight into its electrical properties that cannot be measured by direct current testing facilities. In this work, we used EIS to analyze the recombination resistance, carrier lifetime, capacitance, and conductivity of two typical PbS CQD solar cells Au/PbS-TBAl/ZnO/ITO and Au/PbS-EDT/PbS-TBAl/ZnO/ITO, in this way, to better understand the charge carriers conduction mechanism behind in PbS CQD solar cells, and it provides a guide to design high-performance quantum-dots solar cells. PMID:27176547

  5. Effect of temperature and UV illumination on charge transport mechanisms in DNA

    Science.gov (United States)

    Narenji, Alaleh G.; Goshi, Noah; Bui, Chris; Mokili, John; Kassegne, Sam

    2015-04-01

    Research into the use of DNA molecules as building blocks for nanoelectronics as well as nanosystems continues. Recently, our group has reported significant electrical conductivity in λ-DNA through direct and in-direct measurements involving high-aspect ratio electrodes that eliminate the effect of the substrate. Our results demonstrate that, at moderate to high frequencies, λ-DNA molecular wires show low impedance. In addition, to prove that the conductivity is indeed from DNA bridge, we studied the effect of temperature and UV irradiation on DNA molecular wires. The temperature results indicate that λ-DNA molecular wires have differing impedance responses at two temperature regimes: impedance increases between 4°C - 40°C, then decreases from 40°C to the melting point (~110°C) at which λ-DNA denatures resulting in a complete loss of current transduction. This hysteric and bi-model behavior makes DNA a candidate for nanoelectronics components such as thermal transistors and switches. The data from UV exposure experiments indicates decreased conductivity of λ-DNA molecular wires after UV exposure, due to damage to GC base pairs and phosphate groups reducing the path available for both charge hopping and short-range electron tunneling mechanisms. The lessons learned from these conductivity experiments along with our knowledge of different charge transport mechanisms within DNA can be applied to the design of synthetic molecular wires for the construction of nanoelectronic devices.

  6. Mechanism of Charge Transfer and Recombination Dynamics in Organo Metal Halide Perovskites and Organic Electrodes, PCBM, and Spiro-OMeTAD: Role of Dark Carriers.

    Science.gov (United States)

    Ponseca, Carlito S; Hutter, Eline M; Piatkowski, Piotr; Cohen, Boiko; Pascher, Torbjörn; Douhal, Abderrazzak; Yartsev, Arkady; Sundström, Villy; Savenije, Tom J

    2015-12-30

    Despite the unprecedented interest in organic-inorganic metal halide perovskite solar cells, quantitative information on the charge transfer dynamics into selective electrodes is still lacking. In this paper, we report the time scales and mechanisms of electron and hole injection and recombination dynamics at organic PCBM and Spiro-OMeTAD electrode interfaces. On the one hand, hole transfer is complete on the subpicosecond time scale in MAPbI3/Spiro-OMeTAD, and its recombination rate is similar to that in neat MAPbI3. This was found to be due to a high concentration of dark charges, i.e., holes brought about by unintentional p-type doping of MAPbI3. Hence, the total concentration of holes in the perovskite is hardly affected by optical excitation, which manifested as similar decay kinetics. On the other hand, the decay of the photoinduced conductivity in MAPbI3/PCBM is on the time scale of hundreds of picoseconds to several nanoseconds, due to electron injection into PCBM and electron-hole recombination at the interface occurring at similar rates. These results highlight the importance of understanding the role of dark carriers in deconvoluting the complex photophysical processes in these materials. Moreover, optimizing the preparation processes wherein undesired doping is minimized could prompt the use of organic molecules as a more viable electrode substitute for perovskite solar cell devices. PMID:26636183

  7. Mechanisms of the spatial memory deficits induced by injection of okadaic acid into the Meynert nucleus basalis of rats

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We previously reported that the injection of okadaic acid(OA)into the Meynert nucleus basalis of rats induced spatial memory deficits.The present study was designed to further explore the underlying mechanisms.We found that the level of acetylcholine(Ach)in the hippocampus significantly decreased 24 h after injection of OA into the Meynert nucleus basalis of rats.Simultaneously,spatial memory deficit,PP-2A inhibition and tau hyperphosphorylation at Ser-198/Ser-199/Ser-202 (Tau-1 epitope)and Ser-396/Ser-404(PHF-1 epitope)were observed.With the restoration of hippocampus Ach to normal levels at 48 and 72 h after the injection,the spatial memory deficits,PP-2A inhibition and tau hyperphosphorylation were reversed.It is suggested that injection of OA into the Meynert nucleus basalis of rats may impair the hippocampus-dependent spatial memory through damaging the cholinergic projection between the Meynert nucleus basalis and the hippocampus and the selective inhibition of PP-2A and tau hyperphosphorylation may be at least part of the underlying mechanisms.

  8. Mechanism and optimization of fuel injection parameters on combustion noise of DI diesel engine

    Institute of Scientific and Technical Information of China (English)

    张庆辉; 郝志勇; 郑旭; 杨文英; 毛杰

    2016-01-01

    Combustion noise takes large proportion in diesel engine noise and the studies of its influence factors play an important role in noise reduction. Engine noise and cylinder pressure measurement experiments were carried out. And the improved attenuation curves were obtained, by which the engine noise was predicted. The effect of fuel injection parameters in combustion noise was investigated during the combustion process. At last, the method combining single variable optimization and multivariate combination was introduced to online optimize the combustion noise. The results show that injection parameters can affect the cylinder pressure rise rate and heat release rate, and consequently affect the cylinder pressure load and pressure oscillation to influence the combustion noise. Among these parameters, main injection advance angle has the greatest influence on the combustion noise, while the pilot injection interval time takes the second place, and the pilot injection quantity is of minimal impact. After the optimal design of the combustion noise, the average sound pressure level of the engine is distinctly reduced by 1.0 dB(A) generally. Meanwhile, the power, emission and economy performances are ensured.

  9. Mechanical and Antibacterial Properties of Injection Molded Polypropylene/TiO2 Nano-Composites: Effects of Surface Modification

    Institute of Scientific and Technical Information of China (English)

    Mirigul Altan; Huseyin Yildirim

    2012-01-01

    Polypropylene (PP)/titanium dioxide (TiO2) nano-composites were prepared by melt compounding with a twin screw extruder. Nanoparticles were modified prior to melt mixing with maleic anhydride grafted styreneethylene-butylene-styrene (SEBS-g-MA) and silane. The composites were injection molded and mechanical tests were applied to obtain tensile strength, elastic modulus and impact strength. Antibacterial efficiency test was applied on the injection molded composite plaques by viable cell counting technique. The results showed that the composites including SEBS-g-MA and silane coated TiO2 gave better mechanical properties than the composites without SEBS-g-MA. Antibacterial efficiency of the composites varied according to the dispersion and the concentration of the particles and it was observed that composites at low content of TiO2 showed higher antibacterial property due to the better photocatalytic activity of the particles during UV exposure.

  10. Charge-transfer optical absorption mechanism of DNA:Ag-nanocluster complexes

    Science.gov (United States)

    Longuinhos, R.; Lúcio, A. D.; Chacham, H.; Alexandre, S. S.

    2016-05-01

    Optical properties of DNA:Ag-nanoclusters complexes have been successfully applied experimentally in Chemistry, Physics, and Biology. Nevertheless, the mechanisms behind their optical activity remain unresolved. In this work, we present a time-dependent density functional study of optical absorption in DNA:Ag4. In all 23 different complexes investigated, we obtain new absorption peaks in the visible region that are not found in either the isolated Ag4 or isolated DNA base pairs. Absorption from red to green are predominantly of charge-transfer character, from the Ag4 to the DNA fragment, while absorption in the blue-violet range are mostly associated to electronic transitions of a mixed character, involving either DNA-Ag4 hybrid orbitals or intracluster orbitals. We also investigate the role of exchange-correlation functionals in the calculated optical spectra. Significant differences are observed between the calculations using the PBE functional (without exact exchange) and the CAM-B3LYP functional (which partly includes exact exchange). Specifically, we observe a tendency of charge-transfer excitations to involve purines bases, and the PBE spectra error is more pronounced in the complexes where the Ag cluster is bound to the purines. Finally, our results also highlight the importance of adding both the complementary base pair and the sugar-phosphate backbone in order to properly characterize the absorption spectrum of DNA:Ag complexes.

  11. Experimental and modeling study on charge storage/transfer mechanism of graphene-based supercapacitors

    Science.gov (United States)

    Ban, Shuai; Jing, Xie; Zhou, Hongjun; Zhang, Lei; Zhang, Jiujun

    2014-12-01

    A symmetrical graphene-based supercapacitor is constructed for studying the charge-transfer mechanism within the graphene-based electrodes using both experiment measurements and molecular simulation. The in-house synthesized graphene is characterized by XRD, SEM and BET measurements for morphology and surface area. It is observed that the electric capacity of graphene electrode can be reduced by both high internal resistance and limited mass transfer. Computer modeling is conducted at the molecular level to characterize the diffusion behavior of electrolyte ions to the interior of electrode with emphasis on the unique 2D confinement imposed by graphene layers. Although graphene powder poses a moderate internal surface of 400 m2 g-1, the capacitance performance of graphene electrode can be as good as that of commercial activated carbon which has an overwhelming surface area of 1700 m2 g-1. An explanation to this abnormal correlation is that graphene material has an intrinsic capability of adaptively reorganizing its microporous structure in response to intercalation of ions and immergence of electrolyte solvent. The accessible surface of graphene is believed to be dramatically enlarged for ion adsorption during the charging process of capacitor.

  12. Metal nanoparticles in organic field-effect transistor: Transition from charge trapping to conduction mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Keanchuan, E-mail: lee.kc@petronas.com.my [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Weis, Martin [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia); Chen, Xiangyu; Taguchi, Dai; Manaka, Takaaki [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-03-03

    Self-assembled monolayers of metal nanoparticles (NPs) are envisioned for various devices and have been investigated for possible applications. However, organic envelope of NPs which is required for self-assembling must be often removed prior further device fabrication. Here, we report on effect of ozonolysis on monolayer of silver NPs (Ag NPs) with size of 8 nm and its impact on Ag NPs utilization in organic field-effect transistor. It was found that Ag NPs covered by organics serve like a traps and removal of insulating organics decreases number of traps and consequently increases Ag NPs monolayer conductivity. - Highlights: • Organic field-effect transistor (OFET) with nanoparticle (NP) film was fabricated • Electrical and optical properties of NP and OFET were studied upon UV irradiation • We report a transition from charge trapping to conduction mechanism of NPs in OFET.

  13. Metal nanoparticles in organic field-effect transistor: Transition from charge trapping to conduction mechanism

    International Nuclear Information System (INIS)

    Self-assembled monolayers of metal nanoparticles (NPs) are envisioned for various devices and have been investigated for possible applications. However, organic envelope of NPs which is required for self-assembling must be often removed prior further device fabrication. Here, we report on effect of ozonolysis on monolayer of silver NPs (Ag NPs) with size of 8 nm and its impact on Ag NPs utilization in organic field-effect transistor. It was found that Ag NPs covered by organics serve like a traps and removal of insulating organics decreases number of traps and consequently increases Ag NPs monolayer conductivity. - Highlights: • Organic field-effect transistor (OFET) with nanoparticle (NP) film was fabricated • Electrical and optical properties of NP and OFET were studied upon UV irradiation • We report a transition from charge trapping to conduction mechanism of NPs in OFET

  14. Quantum-mechanical interference in charge exchange between hydrogen and graphene-like surfaces

    International Nuclear Information System (INIS)

    The neutral to negative charge fluctuation of a hydrogen atom in front of a graphene surface is calculated by using the Anderson model within an infinite intra atomic Coulomb repulsion approximation. We perform an ab initio calculation of the Anderson hybridization function that allows investigation of the effect of quantum-mechanical interference related to the Berry phase inherent to the graphene band structure. We find that consideration of the interaction of hydrogen on top of many C atoms leads to a marked asymmetry of the imaginary part of the hybridization function with respect to the Fermi level. Consequently, Fano factors larger than one and strongly dependent on the energy around the Fermi level are predicted. Moreover, the suppression of the hybridization for energies above the Fermi level can explain the unexpected large negative ion formation measured in the scattering of protons by graphite-like surfaces. (paper)

  15. Universal crossover of the charge carrier fluctuation mechanism in different polymer/carbon nanotubes composites

    International Nuclear Information System (INIS)

    Carbon nanotubes added to polymer and epoxy matrices are compounds of interest for applications in electronics and aerospace. The realization of high-performance devices based on these materials can profit from the investigation of their electric noise properties, as this gives a more detailed insight of the basic charge carriers transport mechanisms at work. The dc and electrical noise characteristics of different polymer/carbon nanotubes composites have been analyzed from 10 to 300 K. The results suggest that all these systems can be regarded as random resistive networks of tunnel junctions formed by adjacent carbon nanotubes. However, in the high-temperature regime, contributions deriving from other possible mechanisms cannot be separated using dc information alone. A transition from a fluctuation-induced tunneling process to a thermally activated regime is instead revealed by electric noise spectroscopy. In particular, a crossover is found from a two-level tunneling mechanism, operating at low temperatures, to resistance fluctuations of a percolative network, in the high-temperature region. The observed behavior of 1/f noise seems to be a general feature for highly conductive samples, independent on the type of polymer matrix and on the nanotube density

  16. Universal crossover of the charge carrier fluctuation mechanism in different polymer/carbon nanotubes composites

    Energy Technology Data Exchange (ETDEWEB)

    Barone, C., E-mail: cbarone@unisa.it; Mauro, C.; Pagano, S. [Dipartimento di Fisica “E.R. Caianiello” and CNR-SPIN Salerno, Università di Salerno, I-84084 Fisciano, Salerno (Italy); Landi, G.; Neitzert, H. C. [Dipartimento di Ingegneria Industriale, Università di Salerno, I-84084 Fisciano, Salerno (Italy)

    2015-10-05

    Carbon nanotubes added to polymer and epoxy matrices are compounds of interest for applications in electronics and aerospace. The realization of high-performance devices based on these materials can profit from the investigation of their electric noise properties, as this gives a more detailed insight of the basic charge carriers transport mechanisms at work. The dc and electrical noise characteristics of different polymer/carbon nanotubes composites have been analyzed from 10 to 300 K. The results suggest that all these systems can be regarded as random resistive networks of tunnel junctions formed by adjacent carbon nanotubes. However, in the high-temperature regime, contributions deriving from other possible mechanisms cannot be separated using dc information alone. A transition from a fluctuation-induced tunneling process to a thermally activated regime is instead revealed by electric noise spectroscopy. In particular, a crossover is found from a two-level tunneling mechanism, operating at low temperatures, to resistance fluctuations of a percolative network, in the high-temperature region. The observed behavior of 1/f noise seems to be a general feature for highly conductive samples, independent on the type of polymer matrix and on the nanotube density.

  17. Universal crossover of the charge carrier fluctuation mechanism in different polymer/carbon nanotubes composites

    Science.gov (United States)

    Barone, C.; Landi, G.; Mauro, C.; Neitzert, H. C.; Pagano, S.

    2015-10-01

    Carbon nanotubes added to polymer and epoxy matrices are compounds of interest for applications in electronics and aerospace. The realization of high-performance devices based on these materials can profit from the investigation of their electric noise properties, as this gives a more detailed insight of the basic charge carriers transport mechanisms at work. The dc and electrical noise characteristics of different polymer/carbon nanotubes composites have been analyzed from 10 to 300 K. The results suggest that all these systems can be regarded as random resistive networks of tunnel junctions formed by adjacent carbon nanotubes. However, in the high-temperature regime, contributions deriving from other possible mechanisms cannot be separated using dc information alone. A transition from a fluctuation-induced tunneling process to a thermally activated regime is instead revealed by electric noise spectroscopy. In particular, a crossover is found from a two-level tunneling mechanism, operating at low temperatures, to resistance fluctuations of a percolative network, in the high-temperature region. The observed behavior of 1/f noise seems to be a general feature for highly conductive samples, independent on the type of polymer matrix and on the nanotube density.

  18. Modeling of fluid injection and withdrawal induced fault activation using discrete element based hydro-mechanical and dynamic coupled simulator

    Science.gov (United States)

    Yoon, Jeoung Seok; Zang, Arno; Zimmermann, Günter; Stephansson, Ove

    2016-04-01

    Operation of fluid injection into and withdrawal from the subsurface for various purposes has been known to induce earthquakes. Such operations include hydraulic fracturing for shale gas extraction, hydraulic stimulation for Enhanced Geothermal System development and waste water disposal. Among these, several damaging earthquakes have been reported in the USA in particular in the areas of high-rate massive amount of wastewater injection [1] mostly with natural fault systems. Oil and gas production have been known to induce earthquake where pore fluid pressure decreases in some cases by several tens of Mega Pascal. One recent seismic event occurred in November 2013 near Azle, Texas where a series of earthquakes began along a mapped ancient fault system [2]. It was studied that a combination of brine production and waste water injection near the fault generated subsurface pressures sufficient to induced earthquakes on near-critically stressed faults. This numerical study aims at investigating the occurrence mechanisms of such earthquakes induced by fluid injection [3] and withdrawal by using hydro-geomechanical coupled dynamic simulator (Itasca's Particle Flow Code 2D). Generic models are setup to investigate the sensitivity of several parameters which include fault orientation, frictional properties, distance from the injection well to the fault, amount of fluid withdrawal around the injection well, to the response of the fault systems and the activation magnitude. Fault slip movement over time in relation to the diffusion of pore pressure is analyzed in detail. Moreover, correlations between the spatial distribution of pore pressure change and the locations of induced seismic events and fault slip rate are investigated. References [1] Keranen KM, Weingarten M, Albers GA, Bekins BA, Ge S, 2014. Sharp increase in central Oklahoma seismicity since 2008 induced by massive wastewater injection, Science 345, 448, DOI: 10.1126/science.1255802. [2] Hornbach MJ, DeShon HR

  19. Neuronal Activity Stimulated by Liquid Substrates Injection at Zusanli (ST36 Acupoint: The Possible Mechanism of Aquapuncture

    Directory of Open Access Journals (Sweden)

    Chun-Yen Chen

    2014-01-01

    Full Text Available Aquapuncture is a modified acupuncture technique and it is generally accepted that it has a greater therapeutic effect than acupuncture because of the combination of the acupoint stimulation and the pharmacological effect of the drugs. However, to date, the mechanisms underlying the effects of aquapuncture remain unclear. We hypothesized that both the change in the local spatial configuration and the substrate stimulation of aquapuncture would activate neuronal signaling. Thus, bee venom, normal saline, and vitamins B1 and B12 were injected into a Zusanli (ST36 acupoint as substrate of aquapuncture, whereas a dry needle was inserted into ST36 as a control. After aquapuncture, activated neurons expressing Fos protein were mainly observed in the dorsal horn of the spinal cord in lumbar segments L3–5, with the distribution nearly identical among all groups. However, the bee venom injection induced significantly more Fos-expressing neurons than the other substrates. Based on these data, we suggest that changes in the spatial configuration of the acupoint activate neuronal signaling and that bee venom may further strengthen this neuronal activity. In conclusion, the mechanisms for the effects of aquapuncture appear to be the spatial configuration changes occurring within the acupoint and the ability of injected substrates to stimulate neuronal activity.

  20. Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites

    International Nuclear Information System (INIS)

    Research highlights: → PP/CNFs and PP/TiO2 composites with relative high loading fractions (10, 20, 30 and 35 wt%) were fabricated by inner melt mixing process. Micro tensile test samples were formed by injection molding combined with variotherm process for all composites. → The morphological properties of all nano composites were characterized by WXRD, whose results imply the adding nano fillers did not change the crystal form of PP, but the crystallites size and distance between lattices of crystals were changed with various nano fillers and loading fractions. → DSC analysis show that due to the nucleating function of nano fillers, the peak temperature of crystallization was increased and the peak temperature of crystallization melting was decreased by adding the nanofillers. → The flow ability of nano composites was tested by high pressure single capillary rheometer and the results demonstrate that nano fillers increased the viscosity of PP matrix. → Based on these significant information and analysis foundation of the nano filled composites, the micro weld line samples were formed by injection molding process and characterized by tensile test method. From the achieved results, it can be found that in general, for functional nano filled polymer composites, the mechanical property of micro weld lines were obviously influenced by nano fillers' shape and loading fractions. → The E modulus of micro weld line was increased due to loading CNFs in PP matrix, while the elongation of the micro tensile samples with weld line is considerably decreased comparing with those of unfilled PP samples. The detrimental tensile strength of micro weld lines were observed when CNFs contents increasing, except for at a 10 wt%. → For TiO2 nano particles filled PP, due to the poor dispersion of nano particles, at low loading fraction of 10 wt%, the E modulus and tensile strength of micro weld lines were decreased by filling nano particles, but when the loading fraction is

  1. Mechanisms of Binder Removal Involved in Supercritical Debinding of Injection Moulded Ceramics

    OpenAIRE

    Chartier, Thierry; Delhomme, Eric; Baumard, Jean-François

    1997-01-01

    Extraction of organic additives from extrusion-moulded ceramic parts by supercritical carbon dioxide has proved to be an efficient method for debinding [1, 2]. A model of binder extraction based on diffusion equations was developed. This model was found to be in fair agreement with experimental results. Experimental kinetics of extraction of low melt point paraffins, by supercritical fluids, from injection-moulded samples are now established. A redistribution of the binder in the liquid state...

  2. Flavor Violating Transitions of Charged Leptons from a Seesaw Mechanism of Dimension Seven

    CERN Document Server

    Liao, Yi; Ren, Lu

    2010-01-01

    A mechanism has been suggested recently to generate the neutrino mass out of a dimension-seven operator. This is expected to relieve the tension between the occurrence of tiny neutrino mass and the observability of other physics effects beyond it. Such a mechanism would inevitably entail lepton flavor violating effects. We study in this work the radiative and purely leptonic transitions of the light charged leptons. In so doing we make a systematic analysis of the flavor structure by providing a convenient parametrization of the mass matrices in terms of independent physical parameters and diagonalizing them explicitly. We illustrate our numerical results by sampling over two CP phases and one Yukawa coupling which are the essential parameters in addition to the heavy lepton mass. We find that with the stringent constraints coming from the muon decays taken into account the decays of the tau lepton are severely suppressed in the majority of parameter space. There exist however small regions in which some tau ...

  3. Failure Mechanism of Fast-Charged Lithium Metal Batteries in Liquid Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Dongping; Shao, Yuyan; Lozano, Terence J.; Bennett, Wendy D.; Graff, Gordon L.; Polzin, Bryant; Zhang, Jiguang; Engelhard, Mark H.; Saenz, Natalio T.; Henderson, Wesley A.; Bhattacharya, Priyanka; Liu, Jun; Xiao, Jie

    2015-02-01

    In recent years, lithium anode has re-attracted broad interest because of the necessity of employing lithium metal in the next-generation battery technologies such as lithium sulfur (Li-S) and lithium oxygen (Li-O2) batteries. Fast capacity degradation and safety issue associated with rechargeable lithium metal batteries have been reported, although the fundamental understanding on the failure mechanism of lithium metal at high charge rate is still under debate due to the complicated interfacial chemistry between lithium metal and electrolyte. Herein, we demonstrate that, at high current density, the quick growth of porous solid electrolyte interphase towards bulk lithium, instead of towards the separator, dramatically builds up the cell impedance that directly leads to the cell failure. Understanding the lithium metal failure mechanism is very critical to gauge the various approaches used to address the stability and safety issues associated with lithium metal anode. Otherwise, all cells will fail quickly at high rates before the observation of any positive effects that might be brought from adopting the new strategies to protect lithium.

  4. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Haseroth, Helmut [European Organization for Nuclear Research, Geneva (Switzerland); Hora, Heinrich [New South Wales Univ., Kensington, NSW (Australia)]|[Regensburg Inst. of Tech. (Germany). Anwenderzentrum

    1996-12-31

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10{sup 11} C{sup 4+} ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ``hot`` electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author).

  5. Release of Native-like Gaseous Proteins from Electrospray Droplets via the Charged Residue Mechanism: Insights from Molecular Dynamics Simulations.

    Science.gov (United States)

    McAllister, Robert G; Metwally, Haidy; Sun, Yu; Konermann, Lars

    2015-10-01

    The mechanism whereby gaseous protein ions are released from charged solvent droplets during electrospray ionization (ESI) remains a matter of debate. Also, it is unclear to what extent electrosprayed proteins retain their solution structure. Molecular dynamics (MD) simulations offer insights into the temporal evolution of protein systems. Surprisingly, there have been no all-atom simulations of the protein ESI process to date. The current work closes this gap by investigating the behavior of protein-containing aqueous nanodroplets that carry excess positive charge. We focus on "native ESI", where proteins initially adopt their biologically active solution structures. ESI proceeds while the protein remains entrapped within the droplet. Protein release into the gas phase occurs upon solvent evaporation to dryness. Droplet shrinkage is accompanied by ejection of charge carriers (Na(+) for the conditions chosen here), keeping the droplet at ∼85% of the Rayleigh limit throughout its life cycle. Any remaining charge carriers bind to the protein as the final solvent molecules evaporate. The outcome of these events is largely independent of the initial protein charge and the mode of charge carrier binding. ESI charge states and collision cross sections of the MD structures agree with experimental data. Our results confirm the Rayleigh/charged residue model (CRM). Field emission of excess Na(+) plays an ancillary role by governing the net charge of the shrinking droplet. Models that envision protein ejection from the droplet are not supported. Most nascent CRM ions retain native-like conformations. For unfolded proteins ESI likely proceeds along routes that are different from the native state mechanism explored here. PMID:26325619

  6. Study of the coherent propagation of charged leptons coming from pion and W decay in Bohmian mechanics

    Directory of Open Access Journals (Sweden)

    H Azizakram

    2015-12-01

    Full Text Available Although charged leptons, contrary to neutrinos, cannot oscillate, exploring whether a coherent  superposition of charged lepton states can change to others during the propagation is an important problem in the neutrino oscillation theory. In this paper, we consider electrons and muons coming from the pions and W decays and study their propagation in relativistic Bohmian quantum mechanics. We find out that the Bohmian trajectories of them are separated after atomic distance propagations. In fact, the computed Bohmian trajectories of electrons and muons coming from W and pion decays show that Bohmin results are consistent with those of standard quantum mechanics.

  7. Reciprocity between Charge Injection and Extraction and Its Influence on the Interpretation of Electroluminescence Spectra in Organic Solar Cells

    Science.gov (United States)

    Kirchartz, Thomas; Nelson, Jenny; Rau, Uwe

    2016-05-01

    Reciprocity relations based on the principle of detailed balance have been frequently used to analyze luminescence intensity and the spectrum of organic solar cells. These reciprocity relations were derived for cases where a linear extrapolation of equilibrium conditions to the nonequilibrium situations present during measurements is possible and therefore requires semiconductors with linear recombination mechanisms. Here, we discuss the impact of nonlinear recombination typically found in organic solar cells on the analysis of luminescence spectra and estimate criteria under which reciprocity relations can still be used to analyze the data. We find that depending on the exact application, only for low mobilities μ <10-4 cm2/V s or very asymmetric mobilities do substantial disagreements between simulation and analytical equations occur.

  8. Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2

    International Nuclear Information System (INIS)

    Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS2 upon adsorption of various gas molecules (H2, O2, H2O, NH3, NO, NO2, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the degree of charge transfer between adsorbate and substrate were determined. All evaluated molecules were physisorbed on monolayer WS2 with a low degree of charge transfer and accept charge from the monolayer, except for NH3, which is a charge donor. Band structure calculations showed that the valence and conduction bands of monolayer WS2 are not significantly altered upon adsorption of H2, H2O, NH3, and CO, whereas the lowest unoccupied molecular orbitals of O2, NO, and NO2 are pinned around the Fermi-level when these molecules are adsorbed on monolayer WS2. The phenomenon of Fermi-level pinning was discussed in light of the traditional and orbital mixing charge transfer theories. The impacts of the charge transfer mechanism on Fermi-level pinning were confirmed for the gas molecules adsorbed on monolayer WS2. The proposed mechanism governing Fermi-level pinning is applicable to the systems of adsorbates on recently developed two-dimensional materials, such as graphene and transition metal dichalcogenides

  9. Self-modulation of a long externally injected relativistic charged-particle beam in a laser wake field acceleration scheme. A preliminary quantum-like investigation

    International Nuclear Information System (INIS)

    Recent investigations indicate that sufficiently long beams of charged particles, travelling in a plasma, experience the phenomenon of self-modulation. The self-modulation is driven by the plasma wake field excitation due to the beam itself, and it may become unstable under certain conditions. A preliminary theoretical investigation of the self-modulation of a relativistic charged-particle beam in overdense plasma in the presence of a preformed plasma wave is carried out, within the quantum-like description of charged particle beams provided by the Thermal Wave Model. A simple physical model for the self-modulation is put forward, described by a nonlinear Schrödinger equation coupled with the Poisson-like equation for the plasma wake potential (so-called Fedele–Shukla equations). The physical mechanism is based on the interplay of three concomitant effects, the radial thermal dispersion (associated with the emittance ε), the radial ponderomotive effects of a preexisting plasma wave (which provides the guidance for the beam), and the self-interaction of the plasma wake field generated by the beam itself

  10. Statistical mechanics of dust charging in a multi-ion plasma with negative and positive ionic species

    International Nuclear Information System (INIS)

    On the basis of statistical mechanics and charging kinetics, the charge distribution over uniform size spherical dust particles in a multi-ion plasma comprising of multiple charged negative and positive ions is investigated. Two specific situations where the complex plasma is viz., (i) dark (no emission from dust) and (ii) irradiated by laser light (causing photoemission from dust) have been taken into account. The analytical formulation includes the population balance equation for the charged dust particles along with number and energy balance of the complex plasma constituents. The departure of the results for multi-ion plasma from that in case of usual singly charged positive ion plasma is graphically illustrated and discussed. In contrast to electron-ion plasma, significant number of particles is seen to acquire opposite charge in case of pure positive-negative ion plasma, even in the absence of electron emission from the dust grains. The effects of various plasma parameters viz., number density, particle size, and work function of dust on charge distribution have also been examined

  11. Non-linear charge collection mechanisms in high-speed communication avalanche photodiodes

    International Nuclear Information System (INIS)

    High-speed avalanche photodiodes used in harsh radiation environments such as space or close to HEP experiments suffer from background Single Event Transients due to the generation of high-energy heavy ion secondary recoils and nuclear reactions. These transients degrade the Bit Error Rate of an optical receiver introducing spurious noise. For small high-speed devices, the electron-hole pair density introduced by an MeV ion well exceeds background doping levels in the top active layers leading to the possibility of an anomalous like gain mechanism due to the internal dipolar field generated by the high-injection plasma. In this paper, we examine this possibility and its spatial dependence using a high-energy focussed ion microbeam and the Transient Ion Beam Induced Current technique to measure the Single Event Transient data collected on an InP InGaAs APD device using 6 MeV N and 7 MeV O ions

  12. Mechanism of Charge Transfer from Plasmonic Nanostructures to Chemically Attached Materials.

    Science.gov (United States)

    Boerigter, Calvin; Aslam, Umar; Linic, Suljo

    2016-06-28

    Plasmonic metal nanoparticles can efficiently convert the energy of visible photons into the energy of hot charge carriers within the nanoparticles. These energetic charge carriers can transfer to molecules or semiconductors, chemically attached to the nanoparticles, where they can induce photochemical transformations. Classical models of photoinduced charge excitation and transfer in metals suggest that the majority of the energetic charge carriers rapidly decay within the metal nanostructure before they are transferred into the neighboring molecule or semiconductor, and therefore, the efficiency of charge transfer is low. Herein, we present experimental evidence that calls into question this conventional picture. We demonstrate a system where the presence of a molecule, adsorbed on the surface of a plasmonic nanoparticle, significantly changes the flow of charge within the excited plasmonic system. The nanoparticle-adsorbate system experiences high rates of direct, resonant flow of charge from the nanoparticle to the molecule, bypassing the conventional charge excitation and thermalization process taking place in the nanoparticle. This picture of charge transfer suggests that the yield of extracted hot electrons (or holes) from plasmonic nanoparticles can be significantly higher than the yields expected based on conventional models. We discuss a conceptual physical framework that allows us to explain our experimental observations. This analysis points us in a direction toward molecular control of the charge transfer process using interface and local field engineering strategies. PMID:27268233

  13. Petrophysical and rock-mechanics effects of CO2 injection for enhanced oil recovery

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Hjuler, Morten Leth; Christensen, Helle Foged;

    2014-01-01

    increase in permeability. A decrease in elastic stiffness is indicated by an increase of Biot׳s effective stress coefficient (α) by 1–2%. Nuclear Magnetic Resonance (NMR) data indicated no change in wettability and the samples remained water wet. We found that the effect of CO2 injection on both...... context be noted that the experiments spanned only 8 days, therefore long term effects cannot be ruled out. In spite of weakening of the chalk, we expect only minor mechanical effects, because the weakening also causes a lowering of effective stress due to an increase in effective stress coefficient...

  14. Study of nozzle deposit formation mechanism for direct injection gasoline engines; Chokufun gasoline engine yo nozzle no deposit seisei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, M.; Saito, A. [Toyota Central Research and Development Labs., Inc., Aichi (Japan); Matsushita, S. [Toyota Motor Corp., Aichi (Japan); Shibata, H. [Nippon Soken, Inc., Tokyo (Japan); Niwa, Y. [Denso Corp., Aichi (Japan)

    1997-10-01

    Nozzles in fuel injectors for direct injection gasoline engines are exposed to high temperature combustion gases and soot. In such a rigorous environment, it is a fear that fuel flow rate changes in injectors by deposit formation on nozzles. Fundamental factors of nozzle deposit formation were investigated through injector bench tests and engine dynamometer tests. Deposit formation processes were observed by SEM through engine dynamometer tests. The investigation results reveal nozzle deposit formation mechanism and how to suppress the deposit. 4 refs., 8 figs., 3 tabs.

  15. Mechanism of direct current electrical charge conduction in p-toluenesulfonate doped polypyrrole/carbon composites

    International Nuclear Information System (INIS)

    Polypyrrole/carbon (PPy/C) composites have been synthesized using varying concentration of p-toluenesulfonate (pTS) dopant by surface initiated in-situ chemical oxidative polymerization. The synthesis and influence of pTS on the structure of the PPy/C composites are confirmed by Fourier transform infrared studies and the morphological features have been examined by scanning electron microscopy. X-ray photoelectron spectroscopy, employed to examine the surface composition and doping level of these composites, confirms the anionic doping into the polymer backbone. Electron spin resonance measurement has been carried out on these samples to identify the nature of the charge carriers and their concentration at different doping levels. The dc electrical conductivity of these composites has been measured in the temperature range ∼10–305 K. The observed results have been analyzed in the framework of existing theoretical models. Different Mott's parameters, such as characteristic temperature (T0), density of states at the Fermi level (N(EF)), average hopping distance (R), and average hopping energy (W), evaluated from dc conductivity data supports the applicability of Mott's three dimensional variable range hopping mechanism in this system

  16. Mechanical design and development of analyzing magnet for the RIB charge breeder beam line

    International Nuclear Information System (INIS)

    An iron dominated analyzing magnet of uniform peak field 0.6 T has been developed for Radioactive Ion Beam (RIB) charge breeder beam line at VECC, Kolkata. It has two room temperature coils made of copper having channels for passage of cooling water. The other important parts of the magnet includes two yokes, two poles, vacuum chamber, view port, iron plates and the support structures. The most important properties of magnets designed and fabricated for this application is the need for high field quality. The magnet assembly has got overall dimensions of 1.1 metres x 0.91 metres x 0.63 metres and the required field uniformity is 6 x 10-4 over pole width of ± 2.5 cm. The most critical parameter that has to be maintained to achieve the desired magnetic field is the pole gap of 80 ± 0.25 rom.This paper describes in detail about the mechanical design, coil cooling analysis, development and assembly of this magnet. (author)

  17. Mechanical Properties of Surface-Charged Poly(Methyl Methacrylate as Denture Resins

    Directory of Open Access Journals (Sweden)

    Sang E. Park

    2009-01-01

    Full Text Available The aim of this study was to examine the mechanical properties of a new surface-modified denture resin for its suitability as denture base material. This experimental resin is made by copolymerization of methacrylic acid (MA to poly(methyl methacrylate (PMMA to produce a negative charge. Four experimental groups consisted of Orthodontic Dental Resin (DENTSPLY Caulk as a control and three groups of modified PMMA (mPMMA produced at differing ratios of methacrylic acid (5 : 95, 10 : 90, and 20 : 80 MA : MMA. A 3-point flexural test using the Instron Universal Testing Machine (Instron Corp. measured force-deflection curves and a complete stress versus strain history to calculate the transverse strength, transverse deflection, flexural strength, and modulus of elasticity. Analysis of Variance and Scheffe Post-test were performed on the data. Resins with increased methacrylic acid content exhibited lower strength values for the measured physical properties. The most significant decrease occurred as the methacrylic acid content was increased to 20% mPMMA. No significant differences at P<.05 were found in all parameters tested between the Control and 5% mPMMA.

  18. Charging mechanism of electret film made of potassium-ion-doped SiO2

    Science.gov (United States)

    Hashiguchi, G.; Nakasone, D.; Sugiyama, T.; Ataka, M.; Toshiyoshi, H.

    2016-03-01

    A charging model is proposed for an electret film made of potassium-ion-doped SiO2 that can be formed between the two opposing micro-electrodes of a micro-electrostatic actuator, separated by a microscopic gap. On the basis of experimental evidence that charging only occurs in the positively biased electrode during the charging process and that the charging polarity is negative, we assumed that the cause of the electret charges is negatively charged oxygen ions residing in the SiO2 film, which arise as a consequence of potassium ion depletion. This assumption was supported by SIMS (Secondary Ion Mass Spectroscopy) analyses that indicate the presence of a depletion region of potassium ions near the interface of the silicon and the oxide film on the positively biased electrode. Calculations of the charged potential using Poisson's equation with the spatially distributed negative charges in the depletion region showed good agreement with the measured surface potential. It appears that our charging model can consistently elucidate potassium ion electret technology.

  19. Facet-selective charge carrier transport, deactivation mechanism and stabilization of a Cu2O photo-electro-catalyst.

    Science.gov (United States)

    Li, Yang; Yun, Xiaogang; Chen, Hong; Zhang, Wenqin; Li, Yongdan

    2016-03-14

    A facet-dependent photo-deactivation mechanism of Cu2O was verified and reported, which is caused by the facet-dependent charge carrier transport. During irradiation, the {100} and {110} crystal facets are selectively corroded by the photo-generated holes, while the {111} facets are comparatively stable. PMID:26898270

  20. Low temperature aging mechanism identification and lithium deposition in a large format lithium iron phosphate battery for different charge profiles

    Science.gov (United States)

    Ouyang, Minggao; Chu, Zhengyu; Lu, Languang; Li, Jianqiu; Han, Xuebing; Feng, Xuning; Liu, Guangming

    2015-07-01

    Charging procedures at low temperatures severely shorten the cycle life of lithium ion batteries due to lithium deposition on the negative electrode. In this paper, cycle life tests are conducted to reveal the influence of the charging current rate and the cut-off voltage limit on the aging mechanisms of a large format LiFePO4 battery at a low temperature (-10 °C). The capacity degradation rates accelerate rapidly after the charging current reaches 0.25 C or the cut-off voltage reaches 3.55 V. Therefore the scheduled current and voltage during low-temperature charging should be reconsidered to avoid capacity degradation. Lithium deposition contributes to low-temperature aging mechanisms, as something needle-like which might be deposited lithium is observed on the surface of the negative electrode after disassembling the aged battery cell. To confirm our explanation, incremental capacity analysis (ICA) is performed to identify the characteristics of the lithium deposition induced battery aging mechanisms. Furthermore, the aging mechanism is quantified using a mechanistic model, whose parameters are estimated with the particle swarm optimization algorithm (PSO). The loss of reversible lithium originating from secondary SEI formation and dead lithium is confirmed as the cause of the aging.

  1. Injection-Molded Long-Fiber Thermoplastic Composites: From Process Modeling to Prediction of Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Kunc, Vlastimil; Jin, Xiaoshi; Tucker III, Charles L.; Costa, Franco

    2013-12-18

    This article illustrates the predictive capabilities for long-fiber thermoplastic (LFT) composites that first simulate the injection molding of LFT structures by Autodesk® Simulation Moldflow® Insight (ASMI) to accurately predict fiber orientation and length distributions in these structures. After validating fiber orientation and length predictions against the experimental data, the predicted results are used by ASMI to compute distributions of elastic properties in the molded structures. In addition, local stress-strain responses and damage accumulation under tensile loading are predicted by an elastic-plastic damage model of EMTA-NLA, a nonlinear analysis tool implemented in ABAQUS® via user-subroutines using an incremental Eshelby-Mori-Tanaka approach. Predicted stress-strain responses up to failure and damage accumulations are compared to the experimental results to validate the model.

  2. Numerical analysis of jet injection mechanism of fuel-coolant interactions using MPS

    International Nuclear Information System (INIS)

    The numerical method used in this study is Moving Particle Semi-implicit (MPS) method which is based on moving particles and their interactions. Grids are not necessary, so that large fluid deformation can be calculated without numerical diffusion. To understand the fundamental physics of the jet penetration, water jet injection into a pool of a denser fluid under non-boiling and isothermal conditions is calculated using the MPS method. The density ratio of the denser fluid (Fluorinert) to water is 1.88. The calculation results are compared with experiments which were conducted in the ALPHA/MUSE facility at JAERI. In three-dimensional calculation, the penetration behavior agrees with the experiment. It is found that the jet penetration process is divided to two stages and, at the first stage, the coolant jet can penetrate deeper than existing correlations of breakup length. (author)

  3. Topological effects of charge transfer in telomere G-quadruplex: Mechanism on telomerase activation and inhibition

    CERN Document Server

    Wang, Xin

    2015-01-01

    We explore charge transfer in the telomere G-Quadruplex (TG4) DNA theoretically by the nonequilibrium Green's function method, and reveal the topological effect of charge transport in TG4 DNA. The consecutive TG4(CTG4) is semiconducting with 0.2 ~ 0.3eV energy gap. Charges transfers favorably in the consecutive TG4, but are trapped in the non-consecutive TG4 (NCTG4). The global conductance is inversely proportional to the local conductance for NCTG4. The topological structure transition from NCTG4 to CTG4 induces abruptly ~ 3nA charge current, which provide a microscopic clue to understand the telomerase activated or inhibited by TG4. Our findings reveal the fundamental property of charge transfer in TG4 and its relationship with the topological structure of TG4.

  4. Topological Effects of Charge Transfer in Telomere G-Quadruplex Mechanism on Telomerase Activation and Inhibition

    Science.gov (United States)

    Wang, Xin; Liang, Shi-Dong

    2013-02-01

    We explore the charge transfer in the telomere G-Quadruplex (TG4) DNA theoretically by the nonequilibrium Green's function method, and reveal the topological effect of the charge transport in TG4 DNA. The consecutive TG4 (CTG4) is semiconducting with 0.2 0.3 eV energy gap. Charges transfer favorably in the CTG4, but are trapped in the nonconsecutive TG4 (NCTG4). The global conductance is inversely proportional to the local conductance for NCTG4. The topological structure transition from NCTG4 to CTG4 induces abruptly 3nA charge current, which provide a microscopic clue to understand the telomerase activated or inhibited by TG4. Our findings reveal the fundamental property of charge transfer in TG4 and its relationship with the topological structure of TG4.

  5. Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

    Directory of Open Access Journals (Sweden)

    Dugan Um

    2010-01-01

    Full Text Available As today's machines become increasingly complex in order to handle intricate tasks, the number of sensors must increase for intelligent operations. Given the large number of sensors, detecting, isolating, and then tolerating faulty sensors is especially important. In this paper, we propose fault tolerance architecture suitable for a massive sensor array often found in highly advanced systems such as autonomous robots. One example is the sensitive skin, a type of massive sensor array. The objective of the sensitive skin is autonomous guidance of machines in unknown environments, requiring elongated operations in a remote site. The entirety of such a system needs to be able to work remotely without human attendance for an extended period of time. To that end, we propose a fault-tolerant architecture whereby component and analytical redundancies are integrated cohesively for effective failure tolerance of a massive array type sensor or sensor system. In addition, we discuss the evaluation results of the proposed tolerance scheme by means of fault injection and validation analysis as a measure of system reliability and performance.

  6. Injection Molding of W-Ni-Fe Nanocomposite Powder Prepared by Mechanical Alloying

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanocrystalline 90W-7Ni-3Fe (wt pct) composite powder was prepared by mechanical alloying and mixed with binder to form a feedstock. Its rheological and sintering behaviors were compared with those of the feedstock from the original powder. It is found that milling can increase the maximum powder loading of feedstock and enhance the sintering densification process.

  7. Charge carrier transport mechanisms in perovskite CdTiO3 fibers

    International Nuclear Information System (INIS)

    Electrical transport properties of electrospun cadmium titanate (CdTiO3) fibers have been investigated using ac and dc measurements. Air annealing of as spun fibers at 1000 °C yielded the single phase perovskite fibers having diameter ∼600 nm - 800 nm. Both the ac and dc electrical measurements were carried out at temperatures from 200 K – 420 K. The complex impedance plane plots revealed a single semicircular arc which indicates the interfacial effect due to grain boundaries of fibers. The dielectric properties obey the Maxwell-Wagner theory of interfacial polarization. In dc transport study at low voltages, data show Ohmic like behavior followed by space charge limited current (SCLC) with traps at higher voltages at all temperatures (200 K – 420 K). Trap density in our fibers system is Nt = 6.27 × 1017 /cm3. Conduction mechanism in the sample is governed by 3-D variable range hopping (VRH) from 200 K – 300 K. The localized density of states were found to be N(EF) = 5.51 × 1021 eV−1 cm−3 at 2 V. Other VRH parameters such as hopping distance (Rhop) and hopping energy (Whop) were also calculated. In the high temperature range of 320 K – 420 K, conductivity follows the Arrhenius law. The activation energy found at 2 V is 0.10 eV. Temperature dependent and higher values of dielectric constant make the perovskite CdTiO3 fibers efficient material for capacitive energy storage devices

  8. Molecular mechanisms of gastric epithelial cell adhesion and injection of CagA by Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Backert Steffen

    2011-11-01

    Full Text Available Abstract Helicobacter pylori is a highly successful pathogen uniquely adapted to colonize humans. Gastric infections with this bacterium can induce pathology ranging from chronic gastritis and peptic ulcers to gastric cancer. More virulent H. pylori isolates harbour numerous well-known adhesins (BabA/B, SabA, AlpA/B, OipA and HopZ and the cag (cytotoxin-associated genes pathogenicity island encoding a type IV secretion system (T4SS. The adhesins establish tight bacterial contact with host target cells and the T4SS represents a needle-like pilus device for the delivery of effector proteins into host target cells such as CagA. BabA and SabA bind to blood group antigen and sialylated proteins respectively, and a series of T4SS components including CagI, CagL, CagY and CagA have been shown to target the integrin β1 receptor followed by injection of CagA across the host cell membrane. The interaction of CagA with membrane-anchored phosphatidylserine may also play a role in the delivery process. While substantial progress has been made in our current understanding of many of the above factors, the host cell receptors for OipA, HopZ and AlpA/B during infection are still unknown. Here we review the recent progress in characterizing the interactions of the various adhesins and structural T4SS proteins with host cell factors. The contribution of these interactions to H. pylori colonization and pathogenesis is discussed.

  9. Molecular mechanisms of gastric epithelial cell adhesion and injection of CagA by Helicobacter pylori

    LENUS (Irish Health Repository)

    Backert, Steffen

    2011-11-01

    Abstract Helicobacter pylori is a highly successful pathogen uniquely adapted to colonize humans. Gastric infections with this bacterium can induce pathology ranging from chronic gastritis and peptic ulcers to gastric cancer. More virulent H. pylori isolates harbour numerous well-known adhesins (BabA\\/B, SabA, AlpA\\/B, OipA and HopZ) and the cag (cytotoxin-associated genes) pathogenicity island encoding a type IV secretion system (T4SS). The adhesins establish tight bacterial contact with host target cells and the T4SS represents a needle-like pilus device for the delivery of effector proteins into host target cells such as CagA. BabA and SabA bind to blood group antigen and sialylated proteins respectively, and a series of T4SS components including CagI, CagL, CagY and CagA have been shown to target the integrin β1 receptor followed by injection of CagA across the host cell membrane. The interaction of CagA with membrane-anchored phosphatidylserine may also play a role in the delivery process. While substantial progress has been made in our current understanding of many of the above factors, the host cell receptors for OipA, HopZ and AlpA\\/B during infection are still unknown. Here we review the recent progress in characterizing the interactions of the various adhesins and structural T4SS proteins with host cell factors. The contribution of these interactions to H. pylori colonization and pathogenesis is discussed.

  10. Torque and power characteristics of a helium charged Stirling engine with a lever controlled displacer driving mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Karabulut, H.; Cinar, C.; Oztuerk, E.; Yuecesu, H.S. [Department of Mechanical Technology, Faculty of Technical Education, Gazi University, 06500 Teknikokullar, Ankara (Turkey)

    2010-01-15

    This study presents test results of a Stirling engine with a lever controlled displacer driving mechanism. Tests were conducted with helium and the working fluid was charged into the engine block. The engine was loaded by means of a prony type micro dynamometer. The heat was supplied by a liquefied petroleum gas (LPG) burner. The engine started to run at 118 C hot end temperature and the systematic tests of the engine were conducted at 180 C, 220 C and 260 C hot end external surface temperatures. During the test, cold end temperature was kept at 27 C by means of water circulation. Variation of the shaft torque and power with respect to the charge pressure and hot end temperature were examined. The maximum torque and power were measured as 3.99 Nm and 183 W at 4 bars charge pressure and 260 C hot end temperature. Maximum power corresponded to 600 rpm speed. (author)

  11. Modeling of Steam Distillation Mechanism during Steam Injection Process Using Artificial Intelligence

    OpenAIRE

    2014-01-01

    Steam distillation as one of the important mechanisms has a great role in oil recovery in thermal methods and so it is important to simulate this process experimentally and theoretically. In this work, the simulation of steam distillation is performed on sixteen sets of crude oil data found in the literature. Artificial intelligence (AI) tools such as artificial neural network (ANN) and also adaptive neurofuzzy interference system (ANFIS) are used in this study as effective methods to simulat...

  12. Experiment Study of a Water Injected Twin Screw Compressor for Mechanical Vapor Compression System

    OpenAIRE

    Shen, Jiubing; Tang, Hao; Zhang, Zhen; Xing, Ziwen

    2014-01-01

    The mechanical vapor compression (MVC) system is a promising way for energy saving among energy intensive industries such as desalination, food and beverage, chemistry and waste water concentration etc. In practical its application is limited by the vapor compressor technology which is demanded to have high pressure ratio for large saturation temperature difference and low discharge steam temperature. Due to the ability of wet compression, twin screw compressor can overcome the technical limi...

  13. Crosslinking Characteristics and Mechanical Properties of an Injectable Biomaterial Composed of Polypropylene fumarate and Polycaprolactone Copolymer

    OpenAIRE

    Yan, Jun; Li, Jianmin; Runge, M. Brett; Dadsetan, Mahrokh; Chen, Qingshan; Lu, Lichun; Yaszemski, Michael J.

    2010-01-01

    In this work, a series of copolymers of polypropylene fumarate-co-polycaprolactone (PPF-co-PCL) were synthesized via a three-step polycondensation reaction of oligomeric polypropylene fumarate (PPF) with polycaprolactone (PCL). The effects of PPF precursor molecular weight, PCL precursor molecular weight, and PCL fraction in the copolymer (PCL feed ratio) on the maximum crosslinking temperature, gelation time, and mechanical properties of the crosslinked copolymers were investigated. The maxi...

  14. Influence of Coherent Tunneling and Incoherent Hopping on the Charge Transfer Mechanism in Linear Donor-Bridge-Acceptor Systems.

    Science.gov (United States)

    Li, Guangqi; Govind, Niranjan; Ratner, Mark A; Cramer, Christopher J; Gagliardi, Laura

    2015-12-17

    The mechanism of charge transfer has been observed to change from tunneling to hopping with increasing numbers of DNA base pairs in polynucleotides and with the length of molecular wires. The aim of this paper is to investigate this transition by examining the population dynamics using a tight-binding Hamiltonian with model parameters to describe a linear donor-bridge-acceptor (D-B-A) system. The model includes a primary vibration and an electron-vibration coupling at each site. A further coupling of the primary vibration with a secondary phonon bath allows the system to dissipate energy to the environment and reach a steady state. We apply the quantum master equation (QME) approach, based on second-order perturbation theory in a quantum dissipative system, to examine the dynamical processes involved in charge-transfer and follow the population transfer rate at the acceptor, ka, to shed light on the transition from tunneling to hopping. With a small tunneling parameter, V, the on-site population tends to localize and form polarons, and the hopping mechanism dominates the transfer process. With increasing V, the population tends to be delocalized and the tunneling mechanism dominates. The competition between incoherent hopping and coherent tunneling governs the mechanism of charge transfer. By varying V and the total number of sites, we also examine the onset of the transition from tunneling to hopping with increasing length. PMID:26554424

  15. The 2000 Miyakejima dike injection: insight on the mechanisms governing the dike arrest

    Science.gov (United States)

    Maccaferri, Francesco; Rivalta, Eleonora; Aoki, Yosuke

    2015-04-01

    Magma stored beneath volcanoes is often transported out of the magma chambers by means of laterally propagating dikes, which are magma-filled lenses that grow by fracturing rock at their tips. Lateral dike injections can lead to fissure eruptions if they intersect the flank of the volcano or the Earth's surface. This sometimes occurs tens of kilometers away from the volcanic edifice. The driving force for lateral dike propagation can be a lateral tectonic stress gradient, the stress gradient due to the topography, or simply the overpressure of the magma chamber. Those forces can act together and interact with the magma buoyancy and with structural discontinuities of the crust, such as pre-existing faults. The 2000 dike intrusion at Miyakejima volcano, Izu arc, Japan, propagated laterally for about 40 km and stopped in correspondence of a strike-slip fault system, sub-perpendicular to the dike plane. After stopping, the dike continued to inflate, without further propagation. During this inflation phase several earthquakes with M>6 occurred on that fault system. It has been proposed that the main cause for the dike arrest was the fault-induced stress. Here we use a boundary element approach to study the interplay between a propagating dike and a pre-stressed fault, accounting also for the stress gradient due to the topography overlying the dike. We use a 2D boundary element plain strain model based on the Displacement Discontinuity Method. For the present application, we focus on the coupling between a strike-slip fault and the dike. The dike is propagated by adding an element at the tip. Influx of magma during propagation is provided in order to maintain the dike overpressure large enough to fracture the rocks at the dike tip. By computing the energy released during the dike propagation, our code indicates whether the dike will accelerate, decelerate or stop at a given location. We find that the stress gradient induced by the topography alone is not able to explain

  16. Mechanism of biphasic charge recombination and accumulation in TiO2 mesoporous structured perovskite solar cells.

    Science.gov (United States)

    Wang, Hao-Yi; Wang, Yi; Yu, Man; Han, Jun; Guo, Zhi-Xin; Ai, Xi-Cheng; Zhang, Jian-Ping; Qin, Yujun

    2016-04-28

    Organic-inorganic halide perovskite solar cells are becoming the next big thing in the photovoltaic field owing to their rapidly developing photoelectric conversion performance. Herein, mesoporous structured perovskite devices with various perovskite grain sizes are fabricated by a sequential dropping method, and the charge recombination dynamics is investigated by transient optical-electric measurements. All devices exhibit an overall power conversion efficiency around 15%. More importantly, a biphasic trap-limited charge recombination process is proposed and interpreted by taking into account the specific charge accumulation mechanism in perovskite solar cells. At low Fermi levels, photo-generated electrons predominately populate in the perovskite phase, while at high Fermi levels, most electrons occupy traps in mesoporous TiO2. As a result, the dynamics of charge recombination is, respectively, dominated by the perovskite phase and mesoporous TiO2 in these two cases. The present work would give a new perspective on the charge recombination process in meso-structured perovskite solar cells. PMID:27076212

  17. Investigation of charge trapping mechanism for nanocrystal-based organic nonvolatile floating gate memory devices by band structure analysis

    Science.gov (United States)

    Lee, Dong-Hoon; Lim, Ki-Tae; Park, Eung-Kyu; Shin, Ha-Chul; Kim, Chung Soo; Park, Kee-Chan; Ahn, Joung-Real; Bang, Jin Ho; Kim, Yong-Sang

    2016-05-01

    This paper investigates the charge trapping mechanism and electrical performance of CdSe nanocrystals, such as nanoparticles and nanowires in organic floating gate memory devices. Despite of same chemical component, each nanocrystals show different electrical performances with distinct trapping mechanism. CdSe nanoparticles trap holes in the memory device; on the contrary, nanowires trap electrons. This phenomenon is mainly due to the difference of energy band structures between nanoparticles and nanowires, measured by the ultraviolet photoelectron spectroscopy. Also, we investigated the memory performance with C- V characteristics, charging and discharging phenomena, and retention time. The nanoparticle based hole trapping memory device has large memory window while the nanowire based electron trapping memory shows a narrow memory window. In spite of narrow memory window, the nanowire based memory device shows better retention performance of about 55% of the charge even after 104 sec of charging. The contrasting performance of nanoparticle and nanowire is attributed to the difference in their energy band and the morphology of thin layer in the device. [Figure not available: see fulltext.

  18. Microstructure, surface topography and mechanical properties of slip cast and powder injection moulded microspecimens made of zirconia

    International Nuclear Information System (INIS)

    Investigations on ceramic microspecimens made of Y2O3-stabilized ZrO2 produced by slip casting or micro powder injection moulding are introduced. During the production of the microspecimens, feedstocks and sintering conditions were varied. Differently moulded specimens were examined with respect to their microstructure and surface topography using light microscopy, scanning electron microscopy (SEM) and confocal white light microscopy. Additionally, the mechanical characteristics were investigated by three-point bending tests using a micro universal testing device. The statistical analysis was realised by means of the Weibull theory and interpreted by the aid of SEM images of fracture surfaces. This research allowed to understand correlations between different feedstocks used, process parameters like the sintering conditions applied and the resulting characteristics as well as material properties of the microspecimens. These results could be used to improve the production process. (orig.)

  19. Impact of supercritical CO2 injection on petrophysical and rock mechanics properties of chalk: an experimental study on chalk from South Arne field, North Sea

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Hjuler, Morten Leth; Christensen, Helle Foged;

    2011-01-01

    Changes in chalk due to EOR by injecting supercritical CO2 (CO2-EOR) can ideally be predicted by applying geophysical methods designed from laboratory-determined petrophysical and rock mechanics properties. A series of petrophysical and rock mechanics tests were performed on Ekofisk Formation and...

  20. Influencing Factors for the Microstructure and Mechanical Properties of Micro Porous Titanium Manufactured by Metal Injection Molding

    Directory of Open Access Journals (Sweden)

    Zhen Lu

    2016-04-01

    Full Text Available Porous titanium is a new structural and functional material. It is widely used in many fields since it integrates the properties of biomaterials with those of metallic foam. A new technology that combines both the preparation and forming of porous materials has been proposed in this paper. Moreover, a new solder was developed that could be employed in the joining of porous materials. Influencing factors for microstructure and mechanical properties of the parent material and joint interface are identified. Metal injection molding (MIM technology was used for fabricating porous materials. The feedstock for injection molding of porous titanium powders was prepared from titanium powders and a polymer-based binder system. In addition, the proportion of powder loading and binders was optimized. Through MIM technology, a porous titanium filter cartridge was prepared. For the purpose of investigating the thermal debinding technology of the filter cartridge, effects of the sintering temperature on the porosity, morphology of micropores and mechanical properties were analyzed. It could be found that when the sintering temperature increased, the relative density, bending and compression strength of the components also increased. Moreover, the porosity reached 32.28% when the sintering temperature was 1000 °C. The microstructure morphology indicated that micropores connected with each other. Meanwhile, the strength of the components was relatively high, i.e., the bending and compression strength was 65 and 60 MPa, respectively. By investigating the joining technology of porous filter cartridges, the ideal components of the solder and pressure were determined. Further research revealed that the micropore structure of the joint interface is the same as that of the parent material, and that the bending strength of the joint interface is 40 MPa.

  1. Numerical Simulation and Experimental Investigation of the Viscoelastic Heating Mechanism in Ultrasonic Plasticizing of Amorphous Polymers for Micro Injection Molding

    Directory of Open Access Journals (Sweden)

    Bingyan Jiang

    2016-05-01

    Full Text Available Ultrasonic plasticizing of polymers for micro-injection molding has been proposed and studied for its unique potential in materials and energy-saving. In our previous work, we have demonstrated the characteristics of the interfacial friction heating mechanism in ultrasonic plasticizing of polymer granulates. In this paper, the other important heating mechanism in ultrasonic plasticizing, i.e., viscoelastic heating for amorphous polymer, was studied by both theoretical modeling and experimentation. The influence mechanism of several parameters, such as the initial temperature of the polymer, the ultrasonic frequency, and the ultrasonic amplitude, was investigated. The results from both numerical simulation and experimentation indicate that the heat generation rate of viscoelastic heating can be significantly influenced by the initial temperature of polymer. The glass transition temperature was found to be a significant shifting point in viscoelastic heating. The heat generation rate is relatively low at the beginning and can have a steep increase after reaching glass transition temperature. In comparison with the ultrasonic frequency, the ultrasonic amplitude has much greater influence on the heat generation rate. In light of the quantitative difference in the viscoelastic heating rate, the limitation of the numerical simulation was discussed in the aspect of the assumptions and the applied mathematical models.

  2. High temperature oxidation of metals: vacancy injection and consequences on the mechanical properties

    International Nuclear Information System (INIS)

    The aim of this work is to account for the effects of the high temperature oxidation of metals on their microstructure and their mechanical properties. 'Model' materials like pure nickel, pure iron and the Ni-20Cr alloy are studied. Nickel foils have been oxidised at 1000 C on one side only in laboratory air, the other side being protected from oxidation by a reducing atmosphere. After the oxidation treatment, the unoxidized face was carefully examined by using an Atomic Force Microscope (AFM). Grain boundaries grooves were characterised and their depth were compared to the ones obtained on the same sample heat treated in the reducing atmosphere during the same time. They are found to be much deeper in the case of the single side oxidised samples. It is shown that this additional grooving is directly linked to the growth of the oxide scale on the opposite side and that it can be explained by the diffusion of the vacancies produced at the oxide scale - metal interface, across the entire sample through grain boundaries. Moreover, the comparison between single side oxidised samples and samples oxidised on both sides points out that voids in grain boundaries are only observed in this latter case proving the vacancies condensation in the metal when the two faces are oxidised. The role of the carbon content and the sample's geometry on this phenomenon is examined in detail. The diffusion of vacancies is coupled with the transport of oxygen so that a mechanism of oxygen transport by vacancies is suggested. The tensile tests realised at room temperature on nickel foils (bamboo microstructure) show that the oxide scale can constitute a barrier to the emergence of dislocations at the metal surface. Finally, the Ni-20Cr alloy is tested in tensile and creep tests between 25 and 825 C in oxidising or reducing atmospheres. (author)

  3. Triboelectric-Potential-Regulated Charge Transport Through p-n Junctions for Area-Scalable Conversion of Mechanical Energy.

    Science.gov (United States)

    Meng, Xian Song; Wang, Zhong Lin; Zhu, Guang

    2016-01-27

    Regulation of charge-transport direction is realized through the coupling of triboelectrification, electrostatic induction, and semiconducting properties for area-scalable conversion of mechanical energy. The output current from each unit triboelectric generator can always constructively add up due to the unidirectional flow of electrons. This work proposes a practical and general route to area-scalable applications of the triboelectric generator and other energy-harvesting techniques. PMID:26611707

  4. A quantum mechanically complete study of H+ + Na(3s) → H(2p) + Na+ charge exchange excitation

    International Nuclear Information System (INIS)

    The H+ + Na → H(2p) + Na+ charge exchange reaction has been studied at collision energies between 1 and 5 keV. At 1 and 2 keV impact energy, this study is 'quantum mechanically complete'; three quantities are necessary and sufficient to fully characterize this process. The experiment involves angle-resolved coincident detection of scattered H particles and Lyman-α photons. Comparison is made to the results of eikonal coupled-channel calculations. (author)

  5. Field emission mechanism from nanotubes through gas ionization induced nanoscale surface charging

    CERN Document Server

    Zhan, Changhua

    2012-01-01

    Experimental evidences reported in this letter show that the gas ionization induced positive charge accumulation can lead to the electron field emission from carbon nanotubes (CNTs) in an electrode system with proper range of gap spacing, where the CNT film with ethocel was covered with ZnO nanorods. The hypothesis for illustration is suggested that: 1) the cosmic ray ionization frequency increases 108~1010 times due to the metastable population resulted from the interaction between the gases and the CNTs; 2) the flux of positive charges is enhanced in the converged field due to the ZnO nanostructures. The resulted positive charge local density is high enough to trigger the field emission of the CNTs. The methodology may be useful in particle detectors and ionization gas sensors.

  6. Anion Exchange Capacity As a Mechanism for Deep Soil Carbon Storage in Variable Charge Soils

    Science.gov (United States)

    Dietzen, C.; James, J. N.; Ciol, M.; Harrison, R. B.

    2014-12-01

    Soil is the most important long-term sink for carbon (C) in terrestrial ecosystems, containing more C than plant biomass and the atmosphere combined. However, soil has historically been under-represented in C cycling literature, especially in regards to information about subsurface (>1.0 m) layers and processes. Previous research has indicated that Andisols with large quantities of noncrystalline, variable-charge minerals, including allophane, imogolite, and ferrihydrite, contain more C both in total and at depth than other soil types in the Pacific Northwest. The electrostatic charge of variable-charge soils depends on pH and is sometimes net positive, particularly in acid conditions, such as those commonly developed under the coniferous forests of the Pacific Northwest. However, even soils with a net negative charge may contain a mixture of negative and positive exchange sites and can hold some nutrient anions through the anion exchange capacity. To increase our understanding of the effects of variable-charge on soil organic matter stabilization, deep sampling is under way at the Fall River Long-Term Soil Productivity Site in western Washington. This site has a deep, well-drained soil with few rocks, which developed from weathered basalt and is classified as an Andisol of the Boistfort Series. Samples have been taken to a depth of 3 m at eight depth intervals. In addition to analyzing total soil C, these soils will be analyzed to determine functional groups present, cation exchange capacity, anion exchange capacity, and non-crystalline mineral content. These data will be analyzed to determine any correlations that may exist between these mineralogical characteristics, total soil C, and types of functional groups stored at depth. The most abundant organic functional groups, including carboxylic and phenolic groups, are anionic in nature, and soil positive charge may play an important role in binding and stabilizing soil organic matter and sequestering C.

  7. Modeling of steam distillation mechanism during steam injection process using artificial intelligence.

    Science.gov (United States)

    Daryasafar, Amin; Ahadi, Arash; Kharrat, Riyaz

    2014-01-01

    Steam distillation as one of the important mechanisms has a great role in oil recovery in thermal methods and so it is important to simulate this process experimentally and theoretically. In this work, the simulation of steam distillation is performed on sixteen sets of crude oil data found in the literature. Artificial intelligence (AI) tools such as artificial neural network (ANN) and also adaptive neurofuzzy interference system (ANFIS) are used in this study as effective methods to simulate the distillate recoveries of these sets of data. Thirteen sets of data were used to train the models and three sets were used to test the models. The developed models are highly compatible with respect to input oil properties and can predict the distillate yield with minimum entry. For showing the performance of the proposed models, simulation of steam distillation is also done using modified Peng-Robinson equation of state. Comparison between the calculated distillates by ANFIS and neural network models and also equation of state-based method indicates that the errors of the ANFIS model for training data and test data sets are lower than those of other methods. PMID:24883365

  8. Mechanisms controlling retention during ultrafiltration of charged saccharides: Molecular conformation and electrostatic forces

    DEFF Research Database (Denmark)

    Pinelo, Manuel; Møller, Victor; Prado-Rubio, Oscar A.;

    2013-01-01

    and between solute molecules and membrane material are amongst the key factors determining the separation efficiency during ultrafiltration of charged saccharides. Our hypothesis is that the manipulation of pH in addition to the classic pressure control should enhance the ultrafiltration performance...... for charged saccharides in terms of permeate flux and observed retention of the target molecules. Series of batch ultrafiltrations with carboxy-methyl-cellulose (CMC) showed that an increase of transmembrane pressure (from 2 to 4bars) resulted in higher permeate fluxes and lower observed retentions...

  9. Plasma metabolomic profiling to reveal antipyretic mechanism of Shuang-huang-lian injection on yeast-induced pyrexia rats.

    Directory of Open Access Journals (Sweden)

    Xiaoyan Gao

    Full Text Available Shuang-huang-lian injection (SHLI is a famous Chinese patent medicine, which has been wildly used in clinic for the treatment of acute respiratory tract infection, pneumonia, influenza, etc. The existing randomized controlled trial (RCT studies suggested that SHLI could afford a certain anti-febrile action. However, seldom does research concern the pharmacological mechanisms of SHLI. In the current study, we explored plasma metabolomic profiling technique and selected potential metabolic markers to reveal the antipyretic mechanism of SHLI on yeast-induced pyrexia rat model using UPLC-Q-TOF/MS coupled with multivariate statistical analysis and pattern recognition techniques. We discovered a significant perturbance of metabolic profile in the plasma of fever rats and obvious reversion in SHLI-administered rats. Eight potential biomarkers, i.e. 1 3-hydeoxybutyric acid, 2 leucine, 3 16:0 LPC, 4 allocholic acid, 5 vitamin B2, 6 Cys-Lys-His, 7 18:2 LPC, and 8 3-hydroxychola-7, 22-dien-24-oic acid, were screened out by OPLS-DA approach. Five potential perturbed metabolic pathways, i.e. 1 valine, leucine, and isoleucine biosynthesis, 2 glycerophospholipid metabolism, 3 ketone bodies synthesis and degradation, 4 bile acid biosynthesis, and 5 riboflavin metabolism, were revealed to relate to the antipyretic mechanisms of SHLI. Overall, we investigated antipyretic mechanisms of SHLI at metabolomic level for the first time, and the obtained results highlights the necessity of adopting metabolomics as a reliable tool for understanding the holism and synergism of Chinese patent drug.

  10. On the mechanisms governing dike arrest: Insight from the 2000 Miyakejima dike injection

    Science.gov (United States)

    Maccaferri, F.; Rivalta, E.; Passarelli, L.; Aoki, Y.

    2016-01-01

    significant stress, released gradually during the dike-fault interplay. Our results reveal how the mechanical interaction between dikes and faults may affect the propagation of magmatic intrusions in general. This has implications for our understanding of the geometrical arrangement of rift segments and transform faults in Mid Ocean Ridges, and for the interplay between dikes and dike-induced graben systems.

  11. Charge transport through DNA/DNA duplexes and DNA/RNA hybrids: complex mechanism study

    Czech Academy of Sciences Publication Activity Database

    Kratochvílová, Irena; Vala, M.; Weiter, M.; Špérová, M.; Schneider, Bohdan; Páv, Ondřej; Šebera, Jakub; Rosenberg, Ivan; Sychrovský, Vladimír

    2013-01-01

    Roč. 20, č. 1 (2013), s. 9-9. ISSN 1211-5894. [Discussions in Structural Molecular Biology. Annual Meeting of the Czech Society for Structural Biology /11./. 14.03.2013-16.03.2013, Nové Hrady] Institutional support: RVO:61388963 ; RVO:68378271 ; RVO:86652036 Keywords : charge transport * fluorescence spectroscopy * DFT Subject RIV: CF - Physical ; Theoretical Chemistry

  12. Bactericidal action mechanism of negatively charged food grade clove oil nanoemulsions.

    Science.gov (United States)

    Majeed, Hamid; Liu, Fei; Hategekimana, Joseph; Sharif, Hafiz Rizwan; Qi, Jing; Ali, Barkat; Bian, Yuan-Yuan; Ma, Jianguo; Yokoyama, Wallace; Zhong, Fang

    2016-04-15

    Clove oil (CO) anionic nanoemulsions were prepared with varying ratios of CO to canola oil (CA), emulsified and stabilized with purity gum ultra (PGU), a newly developed succinylated waxy maize starch. Interfacial tension measurements showed that CO acted as a co-surfactant and there was a gradual decrease in interfacial tension which favored the formation of small droplet sizes on homogenization until a critical limit (5:5% v/v CO:CA) was reached. Antimicrobial activity of the negatively charged CO nanoemulsion was determined against Gram positive GPB (Listeria monocytogenes and Staphylococcus aureus) and Gram negative GNB (Escherichia coli) bacterial strains using minimum inhibitory concentration (MIC) and a time kill dynamic method. Negatively charged PGU emulsified CO nanoemulsion showed prolonged antibacterial activities against Gram positive bacterial strains. We concluded that negatively charged CO nanoemulsion droplets self-assemble with GPB cell membrane, and facilitated interaction with cellular components of bacteria. Moreover, no electrostatic interaction existed between negatively charged droplets and the GPB membrane. PMID:26616926

  13. Techniques and mechanisms applied in electron cyclotron resonance sources for highly charged ions

    NARCIS (Netherlands)

    Drentje, AG

    2003-01-01

    Electron cyclotron resonance ion sources are delivering beams of highly charged ions for a wide range of applications in many laboratories. For more than two decades, the development of these ion sources has been to a large extent an intuitive and experimental enterprise. Much effort has been spent

  14. Air Conditioner Charging. Automotive Mechanics. Air Conditioning. Instructor's Guide [and] Student Guide.

    Science.gov (United States)

    Spignesi, B.

    This instructional package, one in a series of individualized instructional units on automobile air conditioning, consists of a student guide and an instructor guide dealing with air conditioning charging. Covered in the module are checking the air conditioning system for leaks, checking and adding refrigerant oil as needed, evacuating the system,…

  15. Preliminary results from a laboratory study of charging mechanisms in a dusty plasma

    International Nuclear Information System (INIS)

    A laboratory investigation has been developed to experimentally study the interaction of micron sized particles with plasmas and electromagnetic radiation. The intent is to investigate under what conditions particles of various compositions and sizes become charged, or discharged, while exposed to an electron beam. Primary emphasis in this report is on secondary emission of electrons. Preliminary results are presented

  16. The charge percolation mechanism and simulation of Ziegler–Natta polymerizations Part III. Oxidation states of transition metals

    Directory of Open Access Journals (Sweden)

    BRANKA PILIC

    2006-04-01

    Full Text Available The oxidation state of the transition metal (Mt active centre is the most disputable question in the polymerization of olefins by Ziegler–Natta (ZN and metallocene complexes. In this paper the importance and the changes of the Mt active centres are presented and discussed on the basis of a charge percolation mechanism (CPM of olefin polymerization. Mt atoms can exist in different oxidation states and can be easily transformed from one to another state during activation. In all cases, the Mt atoms are present in several oxidation states, i.e., Mt+(n-1, Mt+(n to Mt+(n+1, producing an irregular charge distribution over the support surface. There is a tendency to equalize the oxidation states by a charge transfer from Mt+(n–1 (donor toMt+(n+1 (acceptor. This cannot occur since the different oxidation states are highly separated on the support. However, monomer molecules are adsorbed on the support producing clusters with stacked p-bonds, making a p-bond bridge between a donor and an acceptor. Once a bridge is formed (percolation moment, charge transfer occurs. The donor and acceptor equalize their oxidation states simultaneously with the polymerization of the monomer. The polymer chain is desorbed from the support, freeing the surface for subsequent monomer adsorption. The whole process is repeated with the oxidation-reduction of other donor-acceptor ensembles.

  17. An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

    Directory of Open Access Journals (Sweden)

    Parul Chawla

    2014-08-01

    Full Text Available In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO and tri-n-octylphosphine (TOP and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern–Volmer quenching constant (KSV and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor–acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe. Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications.

  18. An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals.

    Science.gov (United States)

    Chawla, Parul; Singh, Son; Sharma, Shailesh Narain

    2014-01-01

    In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe) chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO) and tri-n-octylphosphine (TOP) and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene) polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern-Volmer quenching constant (K SV) and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor-acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe). Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications. PMID:25161859

  19. Mechanism of diapirism and episodic fluid injections in the Yinggehai Basin

    Institute of Scientific and Technical Information of China (English)

    HAO; Fang

    2002-01-01

    [1]Jackson, M. P. A., Vendeville, B. C., Regional extension as a geologic trigger for diapirism, Geological Society of Ameri-ca Bulletin, 1994, 106(1): 57-73.[2]Pérez-Belzuz, F., Alonso, B., Ercilla, G., History of mud diapirism and trigger mechanisms in the Western Alboran Sea, Tectonophysics, 1996, 282(2): 399-422.[3]Hunt, J. M., Petroleum Geology and Geochemistry, 2nd ed., San Francisco: Freeman and Company, 1996, 743.[4]Gong Zaisheng, Li Sitian, Continental Margin Basin Analysis and Hydrocarbon Accumulation of the Northern South Chi-na Sea (in Chinese), Beijing: Science Press, 1997, 510.[5]Price, L. C., Basin richness and source rock disruption: A fundamental relationship? Journal of Petroleum Geology, 1994, 17(1): 5-38.[6]Roberts, S. J., Nunn, J. A., Episodic fluid expulsion from geopressured sediments, Marine and Petroleum Geology, 1995, 12(2): 195-204.[7]Dewers, T., Ortoleva, P., Nonlinear dynamical aspects of deep basin hydrology: Fluid compartment formation and episodic fluid release, American Journal of Science, 1994, 294(5): 713-755.[8]Dai, J. X., Song, Y., Dai, C. S. et al., Geochemistry and accumulation of carbon dioxide gases in China, AAPG Bulletin, 1996, 80(9): 1615-1626.[9]Hao Fang, Li Sitian, Sun Yongchuan et al., Organic maturation and petroleum generation model in the Yinggehai and Qiongdongnan Basins, Science in China, 1996, 39(6): 650-658.[10]Hao Fang, Li Sitian, Dong Weiliang et al., Abnormal organic matter maturation in the Yinggehai Basin, offshore South China Sea: Implications for hydrocarbon expulsion and fluid migration from overpressured systems, Journal of Petroleum Geology, 1998, 21(4): 427-444.[11]Pollastro, R. M., Considerations and applications of the illite/smectite geothermometer in hydrocarbon-bearing rocks of Miocene to Mississippian age, Clays and Clay Minerals, 1993, 41(2): 119-133.[12]Ko, J., Hesse, R., Illite/smectite diagenesis in the Beaufort-Mackenzie Basin, Arctic Canada

  20. Is the fracto-mechanoluminescence of ZnS:Mn phosphor dominated by charged dislocation mechanism or piezoelectrification mechanism?

    Science.gov (United States)

    Chandra, B P; Chandra, V K; Jha, Piyush; Pateria, Deepti; Baghel, R N

    2016-02-01

    Mathematical approaches made for both the charged dislocation model and piezoelectrically induced electron bombardment model of fracto-mechanoluminescence (FML), the luminescence induced by fracture of solids, in ZnS:Mn phosphor indicate that the piezoelectrically induced electron bombardment model provides a dominating process for the FML of ZnS phosphors. The concentration of 3000 ppm Mn(2+) is optimal for ML intensity of ZnS:Mn phosphor. The decay time of ML gives the relaxation time of the piston used to deform the sample and the time tm of maximum of ML is controlled by both the relaxation time of the piston and decay time of charges on the newly created surfaces of crystals. As the product of the velocity of dislocations and pinning time of dislocations gives the mean free path of a moving dislocation. Both factors play an important role in the ML excitation of impurity doped II-VI semiconductors. The linear increase of total ML intensity IT with the impact velocity indicates that the damage increases linearly with impact velocity of the load. Thus, the ML measurement can be used remotely to monitor the real-time damage in the structures, and therefore, the ML of ZnS:Mn phosphor has also the potential for a structural health monitoring system. PMID:25991045

  1. Injectable hydrogel as cell carriers: Mechanism of beta-hairpin peptide hydrogel shear thinning, immediate recovery and effects on encapsulated cell payload

    Science.gov (United States)

    Yan, Congqi

    To facilitate future biomedical treatment with localized delivery and higher therapy efficacy, much research effort has been devoted recently to the development of hydrogel biomaterials to transport a therapy to in vivo target sites via simple syringe or catheter injection. Most injectable hydrogel materials are free flowing precursor solutions ex vivo that become crosslinked into hydrogels once injected in vivo in response to exposure to environmental stimuli. However, properties of the final hydrogel formed in vivo are unpredictable due to possible leakage, dilution or change of injected gel precursor solution. As an alternate, more recent strategy for injectable hydrogel therapies, beta-hairpin peptide-based hydrogels are a class of injectable hydrogel solids with significant potential use in injectable therapies. These physical hydrogels can shear-thin and consequently flow as a low-viscosity material under a sufficient shear stress but immediately recover back into a solid upon removal of the stress, allowing them to be injected as preformed gel solids. The shear-thinning and immediate self-healing properties of self-assembled beta-hairpin peptide hydrogels enable a direct delivery of gel-encapsulated cells via benign injection to tissue defect sites with well-defined final gel properties in vivo. In this dissertation, mechanisms of gel shear-thinning and immediate recovery were elucidated by investigating gel behavior during and after flow via mechanical and structural characterizations. All studied beta-hairpin hydrogels shear-thin during flow (gel network fracture into large hydrogel domains) and instantly recover after cessation of flow (gel domains are percolated which immediately reforms the solid hydrogel). Importantly, hydrogel flow behavior was further studied in a capillary geometry that mimicked the actual situation of syringe injection. It was observed that all beta-hairpin peptide hydrogels investigated displayed a promising flow profile for

  2. THERMO-HYDRO-MECHANICAL MODELING OF WORKING FLUID INJECTION AND THERMAL ENERGY EXTRACTION IN EGS FRACTURES AND ROCK MATRIX

    Energy Technology Data Exchange (ETDEWEB)

    Robert Podgorney; Chuan Lu; Hai Huang

    2012-01-01

    Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing), to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid-heat system and our ability to reliably predict how reservoirs behave under stimulation and production. Reliable performance predictions of EGS reservoirs require accurate and robust modeling for strongly coupled thermal-hydrological-mechanical (THM) processes. Conventionally, these types of problems have been solved using operator-splitting methods, usually by coupling a subsurface flow and heat transport simulators with a solid mechanics simulator via input files. An alternative approach is to solve the system of nonlinear partial differential equations that govern multiphase fluid flow, heat transport, and rock mechanics simultaneously, using a fully coupled, fully implicit solution procedure, in which all solution variables (pressure, enthalpy, and rock displacement fields) are solved simultaneously. This paper describes numerical simulations used to investigate the poro- and thermal- elastic effects of working fluid injection and thermal energy extraction on the properties of the fractures and rock matrix of a hypothetical EGS reservoir, using a novel simulation software FALCON (Podgorney et al., 2011), a finite element based simulator solving fully coupled multiphase fluid flow, heat transport, rock deformation, and fracturing using a global implicit approach. Investigations are also conducted on how these poro- and thermal-elastic effects are related to fracture permeability

  3. Mechanism of Crystallization and Implications for Charge Transport in Poly(3-ethylhexylthiophene) Thin Films

    KAUST Repository

    Duong, Duc T.

    2014-04-09

    In this work, crystallization kinetics and aggregate growth of poly(3-ethylhexylthiophene) (P3EHT) thin films are studied as a function of film thickness. X-ray diffraction and optical absorption show that individual aggregates and crystallites grow anisotropically and mostly along only two packing directions: the alkyl stacking and the polymer chain backbone direction. Further, it is also determined that crystallization kinetics is limited by the reorganization of polymer chains and depends strongly on the film thickness and average molecular weight. Time-dependent, field-effect hole mobilities in thin films reveal a percolation threshold for both low and high molecular weight P3EHT. Structural analysis reveals that charge percolation requires bridged aggregates separated by a distance of ≈2-3 nm, which is on the order of the polymer persistence length. These results thus highlight the importance of tie molecules and inter-aggregate distance in supporting charge percolation in semiconducting polymer thin films. The study as a whole also demonstrates that P3EHT is an ideal model system for polythiophenes and should prove to be useful for future investigations into crystallization kinetics. Recrystallization kinetics and its relationship to charge transport in poly(3-ethylhexylthiophene) (P3EHT) thin films are investigated using a combination of grazing incidence X-ray diffraction, optical absorption, and field-effect transistor measurements. These results show that thin film crystallization kinetics is limited by polymer chain reorganization and that charge percolation depends strongly on the edge-to-edge distance between aggregates. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Unified description of charge transfer mechanisms and vibronic dynamics in nanoscale junctions

    OpenAIRE

    Avriller, R.

    2010-01-01

    We propose a general framework that unifies the point of view of counting statistics of transmitted (fermionic) charges as it is commonly used in the quantum transport community to the point of view of counting statics of phonons (bosons) as it is known from the field of quantum optics. As a particular example, we study on the same footing the counting statistics of electrons transfered through a molecular junction and the corresponding population dynamics of the associated molecular vibratio...

  5. Charge-discharge mechanism of mechanically alloyed NiS used as a cathode in rechargeable lithium batteries

    International Nuclear Information System (INIS)

    Nickel sulfide (NiS) as a cathode material for a lithium rechargeable battery was charged and discharged at elevated temperature (80 deg. C) using a PEO solid polymer electrolyte. In order to synthesize a homogeneous NiS phase, very fine nickel metal powder was ball milled with sulfur powder for 12 h under argon gas. We found using ex-situ XRD measurements that the NiS cathode active material was transformed into other phases such as Ni3S2, nickel and sulfur during discharge. The initial discharge capacity of the NiS positive electrode was 580 mAh/g NiS at 1.5 V vs. Li/Li+ with PEO electrolyte. It has good cycling properties, retaining 93% of the initial discharge capacity even after 200 cycles with a PEO solid polymer electrolyte

  6. Reaction mechanism and nuclear correlations study by low energy pion double charge exchange

    International Nuclear Information System (INIS)

    In pion double-charge-exchange (DCX) reactions, a positive (negative) pion is incident on a nucleus and a negative (positive) pion emerges. These reactions are of fundamental interest since the process must involve at least two nucleons in order to conserve charge. Although two nucleon processes are present in many reactions they are usually masked by the dominant single nucleon processes. DCX is unique in that respect since it is a two nucleon process in lowest order and thus may be sensitive to two-nucleon correlations. Measurements of low energy pion double-charge-exchange reactions to the double-isobaric-analog-state (DIAS) and ground-state (GS) of the residual nucleus provide new means for studying nucleon-nucleon correlations in nuclei. At low energies (Tπ 7/2 shell at energies ranging from 25 to 65 MeV. Cross sections were measured on 42,44,48Ca, 46,50Ti and 54Fe. The calcium isotopes make a good set of nuclei on which to study the effects of correlations in DCX reactions

  7. Electron cooling by the injection of fast neutrals

    International Nuclear Information System (INIS)

    During the initial stages of neutral injection heating of tokamak plasmas the electron temperature often falls. The various processes which account for this effect are discussed analytically. For DITE parameters the most important energy loss mechanism is found to be the radiation produced by charge-exchange recombination of the ionised impurities on the injected neutrals. The experimental time behaviour of OVII line emission is compared with the predictions of an ionisation balance code

  8. Luminance Mechanisms of White Organic Light-Emitting Devices Fabricated Utilizing a Charge Generation Layer with a Light-Emitting Function.

    Science.gov (United States)

    Kim, K H; Jeon, Y P; Choo, D C; Kim, T W

    2015-07-01

    The luminance mechanisms of the white organic light-emitting devices (WOLEDs) with a charge generation layer (CGL) consisting of a tungsten oxide layer and a 5,6,11,12-tetraphenyltetracene (rubrene) doped N,N',-bis-(1-naphthyl)-N,N'-diphenyl1-1'-biphenyl-4,4'-diamine (NPB) layer were investigated. Current densities and luminances of the WOLEDs increased with increasing a rubrene doping concentration because the formation of excitons in the rubrene-doped NPB layer increased due to the more exciton trapping in rubrene molecules and the delay of the electron injection due to the insertion of the litium qunolate layer. The yellow light emitted from the rubrene-doped NPB layer in the CGL combined with the blue light from the main emitting layer of the WOLEDs, resulting in the emission of the white light. The ratio between the yellow and the blue color peak intensities of the electroluminescence spectra for the WOLEDs was controlled by the rubrene doping concentration. The Commission Internationale de l'Eclairage coordinates of the fabricated WOLED were (0.31, 0.42) at 740.7 cd/m2, indicative of white emission color. PMID:26373110

  9. Mechanical properties of silicon nanowire anodes at different states of charge

    OpenAIRE

    Moenig, Reiner

    2014-01-01

    Silicon is considered to be a promising anode material for lithium-ion batteries with very high energy densities. During lithiation, silicon anodes form different Li–Si phases and store up to 3.75 lithium ions per silicon atom. Associated with this high capacity is a volume change of roughly 300% and large mechanical stresses that may affect the electrochemical processes. The stresses that actually form strongly depend on the mechanical properties of the lithium silicides and the mechanical p...

  10. Sintering behavior and mechanical properties of a metal injection molded Ti–Nb binary alloy as biomaterial

    International Nuclear Information System (INIS)

    Highlights: • The sintering of the MIM Ti–Nb alloy consists of three steps. • The Nb particles act as diffusion barriers during sintering. • The TiCx only precipitate in the cooling step during sintering. • The TiCx hardly influence the sintering process of MIM Ti–Nb alloy. • The MIM Ti–Nb alloy exhibits high strength, low Young’s modulus but poor ductility. - Abstract: Sintering behavior, microstructure and mechanical properties of a Ti–16Nb alloy processed by metal injection molding (MIM) technology using elemental powders were investigated in this work by optical microscopy, X-ray diffraction (XRD), dilatometer, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). It was found that from 700 °C to 1500 °C the homogenization and densification process of MIM Ti–16Nb alloy consisted of three steps, i.e., Ti-diffusion-controlled step, Ti–Nb-diffusion step and matrix-diffusion step. Titanium carbide formation was observed in the samples sintered at 1300 °C and 1500 °C, but not in the ones sintered at 900 °C and 1100 °C. The MIM Ti–16Nb specimens sintered at 1500 °C exhibited a good combination of high tensile strength and low Young’s modulus. However, the titanium carbide particles led to poor ductility

  11. Mechanical and thermal properties of conventional and microcellular injection molded poly (lactic acid)/poly (ε-caprolactone) blends.

    Science.gov (United States)

    Zhao, Haibin; Zhao, Guoqun

    2016-01-01

    In view of their complementary properties, blending polylactide (PLA) with poly (ε-caprolactone) (PCL) becomes a good choice to improve PLA's properties without compromising its biodegradability. A series of blends of biodegradable PLA and PCL with different mass fraction were prepared by melt mixing. Standard tensile bars were produced by both conventional and microcellular injection molding to study their mechanical and thermal properties. With the increase in PCL content, the blend showed decreased tensile strength and modulus; however, elongation was dramatically increased. With the addition of PCL, the failure mode changed from brittle fracture of the neat PLA to ductile fracture of the blend as demonstrated by tensile test. Various theoretical models based on dispersion and interface adhesion were used to predict the Young's modulus and the results shows the experimental data are consistent with the predictions of the foam model and Kerner-Uemura-Takayangi model. The thermal behavior of the blends was investigated by DSC and TGA. The melting temperature and the degree of crystallinity of PCL in the PLA/PCL did not significantly change with the PCL content increasing in the whole range of blends composition. PMID:26313249

  12. Sintering behavior and mechanical properties of a metal injection molded Ti–Nb binary alloy as biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dapeng, E-mail: dpzhao@hotmail.com [College of Biology, Hunan University, 410082 Changsha (China); Helmholtz-Zentrum Geesthacht, Institute of Materials Research, D-21502 Geesthacht (Germany); Chang, Keke [RWTH Aachen University, Materials Chemistry, D-52056 Aachen (Germany); Ebel, Thomas [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, D-21502 Geesthacht (Germany); Nie, Hemin [College of Biology, Hunan University, 410082 Changsha (China); Willumeit, Regine; Pyczak, Florian [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, D-21502 Geesthacht (Germany)

    2015-08-15

    Highlights: • The sintering of the MIM Ti–Nb alloy consists of three steps. • The Nb particles act as diffusion barriers during sintering. • The TiC{sub x} only precipitate in the cooling step during sintering. • The TiC{sub x} hardly influence the sintering process of MIM Ti–Nb alloy. • The MIM Ti–Nb alloy exhibits high strength, low Young’s modulus but poor ductility. - Abstract: Sintering behavior, microstructure and mechanical properties of a Ti–16Nb alloy processed by metal injection molding (MIM) technology using elemental powders were investigated in this work by optical microscopy, X-ray diffraction (XRD), dilatometer, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). It was found that from 700 °C to 1500 °C the homogenization and densification process of MIM Ti–16Nb alloy consisted of three steps, i.e., Ti-diffusion-controlled step, Ti–Nb-diffusion step and matrix-diffusion step. Titanium carbide formation was observed in the samples sintered at 1300 °C and 1500 °C, but not in the ones sintered at 900 °C and 1100 °C. The MIM Ti–16Nb specimens sintered at 1500 °C exhibited a good combination of high tensile strength and low Young’s modulus. However, the titanium carbide particles led to poor ductility.

  13. Modeling and Analysis of the Electrokinetic Mass Transport and Adsorption Mechanisms of a Charged Adsorbate in Capillary Electrochromatography Systems Employing Charged Nonporous Adsorbent Particles.

    Science.gov (United States)

    Grimes, B. A.; Liapis, A. I.

    2001-02-01

    Mass-transfer systems based on electrokinetic phenomena (i.e., capillary electrochromatography (CEC)) have shown practical potential for becoming powerful separation methods for the biotechnology and pharmaceutical industries. A dynamic mathematical model, consisting of the momentum balance and the Poisson equations, as well as the unsteady-state continuity expressions for the cation and anion of the background electrolyte and of a positively charged analyte (adsorbate), is constructed and solved to determine quantitatively the electroosmotic velocity, the electrostatic potential, the concentration profiles of the charged species in the double layer and in the electroneutral core region of the fluid in the interstitial channels for bulk flow in the packed chromatographic column, and the axial current density profiles as the adsorbate adsorbs onto the negatively charged fixed sites on the surface of the nonporous particles packed in the chromatographic column. The frontal analysis mode of operation is simulated in this work. The results obtained from model simulations provide significant physical insight into and understanding of the development and propagation of the dynamic profile of the concentration of the adsorbate (analyte) and indicate that sharp, highly resolved adsorption fronts and large amounts of adsorbate in the adsorbed phase for a given column length can be obtained under the following conditions: (i) The ratio, gamma(2, 0), of the electroosmotic velocity of the mobile liquid phase at the column entrance after the adsorption front has passed the column entrance to the electrophoretic velocity of the anion is very close to -1. The structure of the equations of the model and model simulations indicate that a stable adsorption front cannot develop when gamma(2, 0) is less than -1 unless the value of the mobility of the cation is less than the value of the mobility of the analyte, which may be a rare occurrence in practical CEC systems. (ii) The ratio of

  14. Unified description of charge transfer mechanisms and vibronic dynamics in nanoscale junctions.

    Science.gov (United States)

    Avriller, R

    2011-03-16

    We propose a general framework that unifies the description of counting statistics of transmitted (fermionic) charges as it is commonly used in the quantum transport community with the description of counting statistics of phonons (bosons). As a particular example, we study on the same footing the counting statistics of electrons transferred through a molecular junction and the corresponding population dynamics of the associated molecular vibrational mode. In the tunnel limit, non-perturbative results in the electron-phonon interaction are derived that unify complementary approaches based on rate equations or on the use of non-equilibrium Green functions. PMID:21335641

  15. Mechanism of Negative Space Charge in Gas Subjected to Corona Discharge

    OpenAIRE

    S.S. Pimpale

    2004-01-01

    The currents produced by low frequency electrodeless discharge of ozoniser filled with argon at P = 10 mm mercury have been measured using a galvanometer actuated by the crystalrectifier and a resistor of 500 ohm. The measurements have also been made simultaneously with the help of electronic scaler. The data are presented graphically by the plots of current against potential. A change in slope of the curves for a pulse height of 5 V has been attempted on the basis of space-charge-limited cur...

  16. Bone response and mechanical strength of rabbit femoral defects filled with injectable CaP cements containing TGF-beta 1 loaded gelatin microparticles.

    NARCIS (Netherlands)

    Link, D.P.; Dolder, J. van den; Beucken, J.J.J.P van den; Wolke, J.G.C.; Mikos, A.G.; Jansen, J.A.

    2008-01-01

    This study focused at the potential of transforming growth factor beta 1 (TGF-beta 1) loaded gelatin microparticles to enhance the bone response and mechanical strength of rabbit femoral defects filled with injectable calcium phosphate (CaP)/gelatin microparticle composites. Therefore, TGF-beta1 loa

  17. Insights into the mechanisms of electromediated gene delivery and application to the loading of giant vesicles with negatively charged macromolecules

    CERN Document Server

    Portet, Thomas; Teissié, Justin; Dean, David S; Rols, Marie-Pierre

    2011-01-01

    We present experimental results regarding the electrotransfer of plasmid DNA into phosphatidylcholine giant unilamellar vesicles (GUVs). Our observations indicate that a direct entry is the predominant mechanism of electrotransfer. A quantitative analysis of the DNA concentration increments inside the GUVs is also performed, and we find that our experimental data are very well described by a simple theoretical model in which DNA entry is mostly driven by electrophoresis. Our theoretical framework allows for the prediction of the amount of transfered DNA as a function of the electric field parameters, and thus paves the way towards a novel method for encapsulating with high efficiency not only DNA, but any negatively charged macromolecule into GUVs.

  18. The mechanism of the transient depression of the erythropoietic rate induced in the rat by a single injection of uranyl nitrate

    International Nuclear Information System (INIS)

    With the purpose of assessing the effect of uranyl nitrate (UN) on the rate of erythropoiesis, 1 mg/kg of the compound was injected iv to adult female Wistar rats. The dosing vehicle was injected into control animals. A single injection of UN induced a transient depression of the rate of red cell volume 59Fe uptake, which reached its lowest value (68% depression) by the seventh postinjection day. By 14 days, 59Fe incorporation had returned to normal. The amount of iron going to erythroid tissue per hour, reticulocyte count, and immunoreactive erythropoietin concentration in both plasma and kidney extracts were also significantly depressed in UN-treated rats in relation to these values in vehicle-injected rats by the seventh postinjection day. Dose-response curves for exogenous erythropoietin (Epo) performed in polycythemic intact and UN-treated rats 7 days after drug injection revealed a significant depression of the response in UN-injected animals. Moreover, bone marrow cells obtained from rats pretreated with UN formed a reduced number of erythroid colonies in vitro in response to Epo. Therefore, possible mechanisms for the observed transient depression in the rate of erythropoiesis associated with acute UN treatment include decreased Epo production and direct or indirect damage of erythroid progenitor cells

  19. THE INFLUENCE OF SUBSTITUENT ELECTRONIC EFFECT ON ETHYLENE OLIGOMERIZATION ACTIVITIES OF BIS(IMINO)PYRIDYL Fe(II)CATALYSTS: A COMBINED MOLECULAR MECHANICS AND CHARGE EQUILIBRATION METHOD

    Institute of Scientific and Technical Information of China (English)

    Hua-yi Li; Bao-gen Duan; You-liang Hu

    2009-01-01

    Bis(imino)pyridyl Fe(Ⅱ)complexes are important catalysts in ethylene oligomerization for preparing α-olefins.The metal net charge-activity relationship of bis(imino)pyridyl Fe(Ⅱ)complexes was investigated by molecular mechanics (MM)and net charge equilibration(QEq)method with modified Dreiding force field.It was found that metal net charge was in reverse ratio to ethylene oligomerization activity.Electron-donor substituents with less steric hindrance to the central metal were favorable to Fe complex activity.Metal net charge-activity relationship could be used to assist the design of new Fe oligomerization catalysts with higher activity.

  20. Charge exchange produced K-shell x-ray emission from Ar16+ in a tokamak plasma with neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P; Bitter, M; Marion, M; Olson, R E

    2004-12-27

    High-resolution spectroscopy of hot tokamak plasma seeded with argon ions and interacting with an energetic, short-pulse neutral hydrogen beam was used to obtain the first high-resolution K-shell x-ray spectrum formed solely by charge exchange. The observed K-shell emission of Ar{sup 16+} is dominated by the intercombination and forbidden lines, providing clear signatures of charge exchange. Results from an ab initio atomic cascade model provide excellent agreement, validating a semiclassical approach for calculating charge exchange cross sections.

  1. Mechanisms for charge-transfer processes at electrode/solid-electrolyte interfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Chueh, William; El Gabaly Marquez, Farid; Whaley, Josh A.; McCarty, Kevin F.; McDaniel, Anthony H.; Farrow, Roger L.

    2011-11-01

    This report summarizes the accomplishments of a Laboratory-Directed Research and Development (LDRD) project focused on developing and applying new x-ray spectroscopies to understand and improve electric charge transfer in electrochemical devices. Our approach studies the device materials as they function at elevated temperature and in the presence of sufficient gas to generate meaningful currents through the device. We developed hardware and methods to allow x-ray photoelectron spectroscopy to be applied under these conditions. We then showed that the approach can measure the local electric potentials of the materials, identify the chemical nature of the electrochemical intermediate reaction species and determine the chemical state of the active materials. When performed simultaneous to traditional impedance-based analysis, the approach provides an unprecedented characterization of an operating electrochemical system.

  2. Charge storage and tunneling mechanism of Ni nanocrystals embedded HfOx film

    Science.gov (United States)

    Zhu, H. X.; Zhang, T.; Wang, R. X.; Zhang, Y. Y.; Li, L. T.; Qiu, X. Y.

    2016-05-01

    A nano-floating gate memory structure based on Ni nanocrystals (NCs) embedded HfOx film is deposited by means of radio-frequency magnetron sputtering. Microstructure investigations reveal that self-organized Ni-NCs with diameters of 4-8 nm are well dispersed in amorphous HfOx matrix. Pt/Ni-NCs embedded HfOx/Si/Ag capacitor structures exhibit voltage-dependent capacitance-voltage hysteresis, and a maximum flat-band voltage shift of 1.5 V, corresponding to a charge storage density of 6.0 × 1012 electrons/cm2, is achieved. These capacitor memory cells exhibit good endurance characteristic up to 4 × 104 cycles and excellent retention performance of 105 s, fulfilling the requirements of next generation non-volatile memory devices. Schottky tunneling is proven to be responsible for electrons tunneling in these capacitors.

  3. Mechanism of Negative Space Charge in Gas Subjected to Corona Discharge

    Directory of Open Access Journals (Sweden)

    S.S. Pimpale

    2004-04-01

    Full Text Available The currents produced by low frequency electrodeless discharge of ozoniser filled with argon at P = 10 mm mercury have been measured using a galvanometer actuated by the crystalrectifier and a resistor of 500 ohm. The measurements have also been made simultaneously with the help of electronic scaler. The data are presented graphically by the plots of current against potential. A change in slope of the curves for a pulse height of 5 V has been attempted on the basis of space-charge-limited current and mathematically formulated equation, viz ., I =A'.V. t.Vo ; where A' is a constant of proportionality and is equal to 2K/C.P.1t.Rln og (Ro.'! Ri , which can be determined from the known values of reduced mobility of the ions of the space charge (K; the pressure (P ; the radii of outer (Row and inner(R;w cylinders and the over voltages, (t.V A side by side measurement of the light effect, ie, change ± M in the discharge current due °toexternal irradiation, revealed to definite dependence of sign and magnitude of the t.lg on the potential in the system studied. Thus, on irradiation of the discharge by light from a 15 W tungsten filament clear glass bulb, at low potentials [below the first threshold potential of argon, (VJJ, there was practically no variation in the current, while at higher potentials, at and above V ~, the current was completely enhanced. Further, a few ramifications related to defence, of sl~ch instantaneous and reversible photo-variation of discharge current due to radiation, are also described .

  4. Spin injection from a normal metal into a mesoscopic superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Michael J.; Kolenda, Stefan [Institut fuer Nanotechnologie, KIT, 76021 Karlsruhe (Germany); Huebler, Florian [Institut fuer Nanotechnologie, KIT, 76021 Karlsruhe (Germany); Center for Functional Nanostructures, KIT, 76131 Karlsruhe (Germany); Institut fuer Festkoerperphysik, KIT, 76021 Karlsruhe (Germany); Loehneysen, Hilbert v. [Center for Functional Nanostructures, KIT, 76131 Karlsruhe (Germany); Institut fuer Festkoerperphysik, KIT, 76021 Karlsruhe (Germany); Physikalisches Institut, KIT, 76128 Karlsruhe (Germany); Beckmann, Detlef [Institut fuer Nanotechnologie, KIT, 76021 Karlsruhe (Germany); Center for Functional Nanostructures, KIT, 76131 Karlsruhe (Germany)

    2013-07-01

    We report on nonlocal transport in superconductor hybrid structures, with ferromagnetic as well as normal-metal tunnel junctions attached to the superconductor. In the presence of a strong Zeeman splitting of the density of states, both charge and spin imbalance is injected into the superconductor. While previous experiments demonstrated spin injection from ferromagnetic electrodes, we show that spin imbalance is also created for normal-metal injector contacts. Using the combination of ferromagnetic and normal-metal detectors allows us to directly discriminate between charge and spin injection, and demonstrate a complete separation of charge and spin imbalance. The relaxation length of the spin imbalance is of the order of several μm and is found to increase with a magnetic field, but is independent of temperature. We further discuss possible relaxation mechanisms for the explanation of the spin relaxation length.

  5. Spin injection from a normal metal into a mesoscopic superconductor

    International Nuclear Information System (INIS)

    We report on nonlocal transport in superconductor hybrid structures, with ferromagnetic as well as normal-metal tunnel junctions attached to the superconductor. In the presence of a strong Zeeman splitting of the density of states, both charge and spin imbalance is injected into the superconductor. While previous experiments demonstrated spin injection from ferromagnetic electrodes, we show that spin imbalance is also created for normal-metal injector contacts. Using the combination of ferromagnetic and normal-metal detectors allows us to directly discriminate between charge and spin injection, and demonstrate a complete separation of charge and spin imbalance. The relaxation length of the spin imbalance is of the order of several μm and is found to increase with a magnetic field, but is independent of temperature. We further discuss possible relaxation mechanisms for the explanation of the spin relaxation length.

  6. Study on dynamics of photoexcited charge injection and trapping in CdS quantum dots sensitized TiO{sub 2} nanowire array film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Shan; Cheng, Ke; Yuan, Zhanqiang; Xu, Suyun; Cheng, Gang; Du, Zuliang, E-mail: zld@henu.edu.cn [Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng 475004, Henan (China)

    2014-05-19

    The photoexcited electrons transfer dynamics of the CdS quantum dots (QDs) deposited in TiO{sub 2} nanowire array films are studied using surface photovoltage (SPV) and transient photovoltage (TPV) techniques. By comparing the SPV results with different thicknesses of QDs layers, we can separate the dynamic characteristics of photoexcited electrons injection and trapping. It is found that the TPV signals of photoexcited electrons trapped in the CdS QDs occur at timescales of about 2 × 10{sup −8} s, which is faster than that of the photoexcited electrons injected from CdS into TiO{sub 2}. More than 90 nm of the thickness of the CdS QDs layer will seriously affect the photoexcited electrons transfer and injection.

  7. Study on dynamics of photoexcited charge injection and trapping in CdS quantum dots sensitized TiO2 nanowire array film electrodes

    Science.gov (United States)

    Pang, Shan; Cheng, Ke; Yuan, Zhanqiang; Xu, Suyun; Cheng, Gang; Du, Zuliang

    2014-05-01

    The photoexcited electrons transfer dynamics of the CdS quantum dots (QDs) deposited in TiO2 nanowire array films are studied using surface photovoltage (SPV) and transient photovoltage (TPV) techniques. By comparing the SPV results with different thicknesses of QDs layers, we can separate the dynamic characteristics of photoexcited electrons injection and trapping. It is found that the TPV signals of photoexcited electrons trapped in the CdS QDs occur at timescales of about 2 × 10-8 s, which is faster than that of the photoexcited electrons injected from CdS into TiO2. More than 90 nm of the thickness of the CdS QDs layer will seriously affect the photoexcited electrons transfer and injection.

  8. Charge-carrier transport mechanisms in composites containing carbon-nanotube inclusions

    International Nuclear Information System (INIS)

    From the microwave-radiation transmittance and reflectance spectra, the temperature dependence of the complex permittivity of carbon nanotubes, subjected to high-temperature annealing, and composite materials produced on their basis is determined. The electron transport mechanisms in composites with inclusions of unannealed carbon nanotubes and nanotubes subjected to high-temperature annealing are determined. The influence of the annealing temperature on the parameters that are characteristic of these mechanisms and control the temperature dependence of the conductivity of multiwall carbon nanotubes is established

  9. Charge-carrier transport mechanisms in composites containing carbon-nanotube inclusions

    Energy Technology Data Exchange (ETDEWEB)

    Usanov, D. A., E-mail: UsanovDA@info.sgu.ru; Skripal’, A. V.; Romanov, A. V. [Saratov State University (Russian Federation)

    2015-12-15

    From the microwave-radiation transmittance and reflectance spectra, the temperature dependence of the complex permittivity of carbon nanotubes, subjected to high-temperature annealing, and composite materials produced on their basis is determined. The electron transport mechanisms in composites with inclusions of unannealed carbon nanotubes and nanotubes subjected to high-temperature annealing are determined. The influence of the annealing temperature on the parameters that are characteristic of these mechanisms and control the temperature dependence of the conductivity of multiwall carbon nanotubes is established.

  10. Organic Chemistry Students' Ideas about Nucleophiles and Electrophiles: The Role of Charges and Mechanisms

    Science.gov (United States)

    Anzovino, Mary E.; Bretz, Stacey Lowery

    2015-01-01

    Organic chemistry students struggle with reaction mechanisms and the electron-pushing formalism (EPF) used by practicing organic chemists. Faculty have identified an understanding of nucleophiles and electrophiles as one conceptual prerequisite to mastery of the EPF, but little is known about organic chemistry students' knowledge of nucleophiles…

  11. Planar supersymmetric quantum mechanics of a charged particle in an external electromagnetic field

    International Nuclear Information System (INIS)

    The supersymmetric quantum mechanics of a two-dimensional non-relativistic particle subject to external magnetic and electric fields is studied in a superfield formulation and with the typical non-minimal coupling of (2+1) dimensions. Both the N=1 and N=2 cases are contemplated and the introduction of the electric interaction is suitably analysed

  12. Planar supersymmetric quantum mechanics of a charged particle in an external electromagnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Paschoal, Ricardo C. [Servico Nacional de Aprendizagem Industrial, Rio de Janeiro, RJ (Brazil). Centro de Tecnologia da Industria Quimica e Textil (SENAI/CETIQT)]. E-mail: paschoal@cbpf.br; Helayel-Neto, Jose A.; Assis, Leonardo P.G. de [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]|[Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); E-mails: helayel@cbpf.br; lpgassis@cbpf.br

    2004-07-01

    The supersymmetric quantum mechanics of a two-dimensional non-relativistic particle subject to both magnetic and electric fields is studied in a superfield formulation and with the typical non-minimal coupling of (2+1) dimensions. Both the N=1 and N=2 cases are contemplated and the introduction of the electric interaction is suitably analysed. (author)

  13. Planar supersymmetric quantum mechanics of a charged particle in an external electromagnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Paschoal, Ricardo C. [Centro Brasileiro de Pesquisas Fisicas, CBPF, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil) and Servico Nacional de Aprendizagem Industrial, Centro de Tecnologia da Industria Quimica e Textil, SENAI/CETIQT, Rua Dr. Manoel Cotrim 195, 20961-040 Rio de Janeiro, RJ (Brazil)]. E-mail: paschoal@cbpf.br; Helayel-Neto, Jose A. [Centro Brasileiro de Pesquisas Fisicas, CBPF, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil) and Grupo de Fisica Teorica Jose Leite Lopes, P.O. Box 91933, 25685-970 Petropolis, RJ (Brazil)]. E-mail: helayel@cbpf.br; Assis, Leonardo P.G. de [Centro Brasileiro de Pesquisas Fisicas, CBPF, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil) and Grupo de Fisica Teorica Jose Leite Lopes, P.O. Box 91933, 25685-970 Petropolis, RJ (Brazil)]. E-mail: lpgassis@cbpf.br

    2006-01-09

    The supersymmetric quantum mechanics of a two-dimensional non-relativistic particle subject to external magnetic and electric fields is studied in a superfield formulation and with the typical non-minimal coupling of (2+1) dimensions. Both the N=1 and N=2 cases are contemplated and the introduction of the electric interaction is suitably analysed.

  14. Planar supersymmetric quantum mechanics of a charged particle in an external electromagnetic field

    International Nuclear Information System (INIS)

    The supersymmetric quantum mechanics of a two-dimensional non-relativistic particle subject to both magnetic and electric fields is studied in a superfield formulation and with the typical non-minimal coupling of (2+1) dimensions. Both the N=1 and N=2 cases are contemplated and the introduction of the electric interaction is suitably analysed. (author)

  15. Isospin-violating meson-nucleon vertices as an alternate mechanism of charge-symmetry breaking

    International Nuclear Information System (INIS)

    We compute isospin-violating meson-nucleon coupling constants and their consequent charge-symmetry-breaking (CSB) nucleon-nucleon potentials. The couplings result from evaluating matrix elements of quark currents between nucleon states in a nonrelativistic constituent quark model; the isospin violations arise from the difference in the up and down constituent quark masses. We find, in particular, that isospin violation in the omega-meson endash nucleon vertex dominates the class IV CSB potential obtained from these considerations. We evaluate the resulting spin-singlet endash triplet mixing angles, the quantities germane to the difference of neutron and proton analyzing powers measured in elastic n searrow-p searrow scattering, and find them commensurate to those computed originally using the on-shell value of the ρ-ω mixing amplitude. The use of the on-shell ρ-ω mixing amplitude at q2=0 has been called into question; rather, the amplitude is zero in a wide class of models. Our model possesses no contribution from ρ-ω mixing at q2=0, and we find that omega-meson exchange suffices to explain the measured n-p analyzing power difference at 183 MeV. copyright 1996 The American Physical Society

  16. Compact Modeling of Floating-Base Effect in Injection-Enhanced Insulated-Gate Bipolar Transistor Based on Potential Modification by Accumulated Charge

    Science.gov (United States)

    Yamamoto, Takao; Miyake, Masataka; Miura-Mattausch, Mitiko

    2013-04-01

    We have developed a compact model of the injection-enhanced insulated-gate bipolar transistor (IGBT) applicable for circuit optimization. The main development is modeling the hole accumulation in the floating-base region. It is demonstrated that the observed negative gate capacitance is well reproduced with the developed model.

  17. Mechanism of hole injection enhancement in light-emitting diodes by inserting multiple hole-reservoir layers in electron blocking layer

    Science.gov (United States)

    Zhao, Yukun; Yun, Feng; Wang, Shuai; Feng, Lungang; Su, Xilin; Li, Yufeng; Guo, Maofeng; Ding, Wen; Zhang, Ye

    2016-03-01

    In this study, gallium nitride (GaN) based light-emitting diodes (LEDs) with single and multiple hole-reservoir layers (HRLs) inserted in the electron-blocking layer (EBL) have been investigated numerically and experimentally. According to simulation results, a better electron confinement and a higher hole injection level can be achieved by the multiple HRLs inserted in the EBL region. To further reveal the underlying mechanism of hole injection enhancement experimentally, the active regions were intentionally designed to emit photons with three different wavelengths of 440 nm, 460 nm, and 480 nm, respectively. Based on the experimental results of photoluminescence (PL) and time-resolved PL (TRPL) measurements conducted at 298 K, the remarkable enhancement (148%) of PL intensities and significant increase in the decay times of the quantum wells close to p-GaN can be obtained. Therefore, the mechanism is proposed that carriers are able to reserve in the EBL region with multiple HRLs for a much longer time. Meanwhile, carriers could diffuse into the active region by tunnelling and/or thermo-electronic effect and then recombine efficiently, leading to the better carrier reservoir effect and higher hole injection in LEDs. As a result, by inserting multiple HRLs in the EBL region instead of single HRL, the experimental external quantum efficiency is enhanced by 19.8%, while the serious droop ratio is markedly suppressed from 37.0% to 27.6% at the high current injection of 100 A/cm2.

  18. Precompound charged particle emission (PCE). A mechanism beyond element production by complete fusion

    International Nuclear Information System (INIS)

    The scaling parameter Z2/A, the ratio of Coulomb to nuclear forces, governs nuclear fission and fusion. Nuclear structure of the collision partners modifies this scaling. Complete fusion (xn-reactions) is restricted to values of the effective fissility xeff≤0.80 The cross sections decrease in the range xeff=0.72 to 0.80 by five orders of magnitude. This abrupt break-down was called ''The Coulomb Falls'' of cross sections. Fusion at this limits is observed in a window of projectile energies reaching just the barrier of nuclear contact at a distance of the collision partner of about (11±1) fm. To reach the spherical ground-state configuration at a distance of (6±2) fm a long gap has to be bridgeddiffusing against a repelling potential. Such a process is slow, in the range of 10-20 s. During this time precompound particles have a chance to be emitted. Beyond complete fusion and before the onset of incomplete fusion such a precompound emission process may be situated. There is evidence that precompound emission plays an important role at the limits of complete fusion, which is reached by today's sensitivity of our experimental methods in the range below 1 pb. In the sediments of the ''Coulomb Falls'', in the range (10-0.1) pb, the Precompound Charged particle Emission (PCE) is to be found. Supporting observations are discussed. Applying PCE to 48Ca-induced reactions on the heaviest actinide-targets opens an alternative interpretation of the Dubna experiments. (orig.)

  19. Negative Ion MALDI Mass Spectrometry of Polyoxometalates (POMs): Mechanism of Singly Charged Anion Formation and Chemical Properties Evaluation

    Science.gov (United States)

    Boulicault, Jean E.; Alves, Sandra; Cole, Richard B.

    2016-08-01

    MALDI-MS has been developed for the negative ion mode analysis of polyoxometalates (POMs). Matrix optimization was performed using a variety of matrix compounds. A first group of matrixes offers MALDI mass spectra containing abundant intact singly charged anionic adduct ions, as well as abundant in-source fragmentations at elevated laser powers. A relative ranking of the ability to induce POM fragmentation is found to be: DAN > CHCA > CNA > DIT> HABA > DCTB > IAA. Matrixes of a second group provide poorer quality MALDI mass spectra without observable fragments. Sample preparation, including the testing of salt additives, was performed to optimize signals for a model POM, POMc12, the core structure of which bears four negative charges. The matrix 9-cyanoanthracene (CNA) provided the best signals corresponding to singly charged intact POMc12 anions. Decompositions of these intact anionic species were examined in detail, and it was concluded that hydrogen radical-induced mechanisms were not prevalent, but rather that the observed prompt fragments originate from transferred energy derived from initial electronic excitation of the CNA matrix. Moreover, in obtained MALDI mass spectra, clear evidence of electron transfer to analyte POM species was found: a manifestation of the POMs ability to readily capture electrons. The affinity of polyanionic POMc12 toward a variety of cations was evaluated and the following affinity ranking was established: Fe3+ > Al3+ > Li+ > Ga3+ > Co2+ > Cr3+ > Cu2+ > [Mn2+, Mg2+] > [Na+, K+]. Thus, from the available cationic species, specific adducts are preferentially formed, and evidence is given that these higher affinity POM complexes are formed in the gas phase during the early stages of plume expansion.

  20. Negative Ion MALDI Mass Spectrometry of Polyoxometalates (POMs): Mechanism of Singly Charged Anion Formation and Chemical Properties Evaluation

    Science.gov (United States)

    Boulicault, Jean E.; Alves, Sandra; Cole, Richard B.

    2016-05-01

    MALDI-MS has been developed for the negative ion mode analysis of polyoxometalates (POMs). Matrix optimization was performed using a variety of matrix compounds. A first group of matrixes offers MALDI mass spectra containing abundant intact singly charged anionic adduct ions, as well as abundant in-source fragmentations at elevated laser powers. A relative ranking of the ability to induce POM fragmentation is found to be: DAN > CHCA > CNA > DIT> HABA > DCTB > IAA. Matrixes of a second group provide poorer quality MALDI mass spectra without observable fragments. Sample preparation, including the testing of salt additives, was performed to optimize signals for a model POM, POMc12, the core structure of which bears four negative charges. The matrix 9-cyanoanthracene (CNA) provided the best signals corresponding to singly charged intact POMc12 anions. Decompositions of these intact anionic species were examined in detail, and it was concluded that hydrogen radical-induced mechanisms were not prevalent, but rather that the observed prompt fragments originate from transferred energy derived from initial electronic excitation of the CNA matrix. Moreover, in obtained MALDI mass spectra, clear evidence of electron transfer to analyte POM species was found: a manifestation of the POMs ability to readily capture electrons. The affinity of polyanionic POMc12 toward a variety of cations was evaluated and the following affinity ranking was established: Fe3+ > Al3+ > Li+ > Ga3+ > Co2+ > Cr3+ > Cu2+ > [Mn2+, Mg2+] > [Na+, K+]. Thus, from the available cationic species, specific adducts are preferentially formed, and evidence is given that these higher affinity POM complexes are formed in the gas phase during the early stages of plume expansion.

  1. Selection of tRNA charging quality control mechanisms that increase mistranslation of the genetic code

    DEFF Research Database (Denmark)

    Yadavalli, Srujana S; Ibba, Michael

    2013-01-01

    Mistranslation can follow two events during protein synthesis: production of non-cognate amino acid:transfer RNA (tRNA) pairs by aminoacyl-tRNA synthetases (aaRSs) and inaccurate selection of aminoacyl-tRNAs by the ribosome. Many aaRSs actively edit non-cognate amino acids, but editing mechanisms...... are not evolutionarily conserved, and their physiological significance remains unclear. To address the connection between aaRSs and mistranslation, the evolutionary divergence of tyrosine editing by phenylalanyl-tRNA synthetase (PheRS) was used as a model. Certain PheRSs are naturally error prone...

  2. Combustion Characteristics of C5 Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

    KAUST Repository

    Park, Sungwoo

    2015-10-27

    C5 alcohols are considered alternative fuels because they emit less greenhouse gases and fewer harmful pollutants. In this study, the combustion characteristics of 2-methylbutanol (2-methyl-1-butanol) and isopentanol (3-methyl-1-butanol) and their mixtures with primary reference fuels (PRFs) were studied using a detailed chemical kinetic model obtained from merging previously published mechanisms. Ignition delay times of the C5 alcohol/air mixtures were compared to PRFs at 20 and 40 atm. Reaction path analyses were conducted at intermediate and high temperatures to identify the most influential reactions controlling ignition of C5 alcohols. The direct relation graph with expert knowledge methodology was used to eliminate unimportant species and reactions in the detailed mechanism, and the resulting skeletal mechanism was tested at various homogeneous charge compression ignition (HCCI) engine combustion conditions. These simulations were used to investigate the heat release characteristics of the methyl-substituted C5 alcohols, and the results show relatively strong reactions at intermediate temperatures prior to hot ignition. C5 alcohol blending in PRF75 in HCCI combustion leads to a significant decrease of low-temperature heat release (LTHR) and a delay of the main combustion. The heat release features demonstrated by C5 alcohols can be used to improve the design and operation of advanced engine technologies.

  3. Evaluation of Electrochemical Charge Storage Mechanism and Structural Changes in Intertwined MoO3–MWCNTs Composites for Supercapacitor Applications

    International Nuclear Information System (INIS)

    Intertwined composites of molybdenum trioxide and multiwall carbon nanotubes (MoO3–MWCNTs) were synthesized by a hydrothermal method for high performance electrochemical energy storage devices. Specific capacitance measurements revealed cycle dependent behavior, which was examined by cyclic voltammetry and impedance spectroscopy. The capacitive charge-storage properties of intertwined MoO3–MWCNTs were found to be superior to those of either MoO3 nanowires or randomly entangled mesoporous MWCNTs. This study showed that double-layer, faradaic and intercalation mechanisms are in operation in the charge storage process. This rather complicated mechanism causes irreversible structural modifications to the oxide lattice, which were verified systematically by various characterization techniques. The intertwined nanocomposites showed increased charge-storage capacity without compromising the charge/discharge kinetics in MWCNTs or MoO3 nanowires. The use of such intertwined nanocomposites is quite promising for electrochemical energy storage devices in portable electrical vehicles

  4. Analysis of charge transfer mechanism on (Ba1-xNdxCuO2+d)2/(CaCuO2)n superconducting superlattices by thermoelectric power measurements

    OpenAIRE

    Putti, M.; Marre', D.; Pallecchi, I.; Medaglia, P. G.; Tebano, A; Balestrino, G.

    2004-01-01

    We have investigated the charge transfer mechanism in artificial superlattices by Seebeck effect measurements. Such a technique allows a precise determination of the amount of charge transferred on each CuO2 plane. A systematic characterization of thermoelectric power in (BaCuO2+d)2/(CaCuO2)n and (Ba0.9Nd0.1CuO2+d)2/(CaCuO2)n superlattices demonstrates that electrical charge distributes uniformly among the CuO2 planes in the Ca-block. The differences observed in the Seebeck effect behavior be...

  5. Oxacillin Injection

    Science.gov (United States)

    Oxacillin injection is used to treat infections caused by certain bacteria. Oxacillin injection is in a class of medications called ... It works by killing bacteria.Antibiotics such as oxacillin injection will not work for colds, flu, or ...

  6. Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene

    Science.gov (United States)

    Huang, Chunli; Chong, Y. D.; Cazalilla, Miguel A.

    2016-08-01

    Spintronics—the all-electrical control of the electron spin for quantum or classical information storage and processing—is one of the most promising applications of the two-dimensional material graphene. Although pristine graphene has negligible spin-orbit coupling (SOC), both theory and experiment suggest that SOC in graphene can be enhanced by extrinsic means, such as functionalization by adatom impurities. We present a theory of transport in graphene that accounts for the spin-coherent dynamics of the carriers, including hitherto-neglected spin precession processes taking place during resonant scattering in the dilute impurity limit. We uncover an "anisotropic spin precession" (ASP) scattering process in graphene, which contributes a large current-induced spin polarization and modifies the standard spin Hall effect. ASP scattering arises from two dimensionality and extrinsic SOC, and apart from graphene, it can be present in other 2D materials or in the surface states of 3D materials with a fluctuating SOC. Our theory also yields a comprehensive description of the spin relaxation mechanisms present in adatom-decorated graphene, including Elliot-Yafet and D'yakonov-Perel relaxation rates, the latter of which can become an amplification process in a certain parameter regime of the SOC disorder potential. Our work provides theoretical foundations for designing future graphene-based integrated spintronic devices.

  7. Charge transport in C60-based dumbbell-type molecules: mechanically induced switching between two distinct conductance states.

    Science.gov (United States)

    Moreno-García, Pavel; La Rosa, Andrea; Kolivoška, Viliam; Bermejo, Daniel; Hong, Wenjing; Yoshida, Koji; Baghernejad, Masoud; Filippone, Salvatore; Broekmann, Peter; Wandlowski, Thomas; Martín, Nazario

    2015-02-18

    Single molecule charge transport characteristics of buckminsterfullerene-capped symmetric fluorene-based dumbbell-type compound 1 were investigated by scanning tunneling microscopy break junction (STM-BJ), current sensing atomic force microscopy break junction (CS-AFM-BJ), and mechanically controlled break junction (MCBJ) techniques, under ambient conditions. We also show that compound 1 is able to form highly organized defect-free surface adlayers, allowing the molecules on the surface to be addressed specifically. Two distinct single molecule conductance states (called high G(H)(1) and low G(L)(1)) were observed, depending on the pressure exerted by the probe on the junction, thus allowing molecule 1 to function as a mechanically driven molecular switch. These two distinct conductance states were attributed to the electron tunneling through the buckminsterfullerene anchoring group and fully extended molecule 1, respectively. The assignment of conductance features to these configurations was further confirmed by control experiments with asymmetrically designed buckminsterfullerene derivative 2 as well as pristine buckminsterfullerene 3, both lacking the G(L) feature. PMID:25651069

  8. A new pathway of Saturnian ring-ionosphere coupling via charged nanograins

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chin-Min; Ip, Wing-Huen, E-mail: wingip@astro.ncu.edu.tw [Institute of Space Science, National Central University, Jhongli City, Taoyuan County 32001, Taiwan (China)

    2014-05-01

    From a re-examination of the trajectories of small charged grains in the vicinity of the Saturnian rings, it is shown that the orbital motion of positively charged grains with a charge-to-mass ratio on the order of 10{sup –6} e amu{sup –1} could allow the injection of water material into the equatorial atmosphere. Thus, a mechanism of ionospheric depletion in the equatorial region is provided, as indicated by the Cassini radio occultation measurements.

  9. In Situ PL and SPV Monitored Charge Carrier Injection During Metal Assisted Etching of Intrinsic a-Si Layers on c-Si.

    Science.gov (United States)

    Greil, Stefanie M; Rappich, Jörg; Korte, Lars; Bastide, Stéphane

    2015-06-01

    Although hydrogenated amorphous silicon is already widely examined regarding its structural and electronic properties, the chemical etching behavior of this material is only roughly understood. We present a detailed study of the etching properties of intrinsic hydrogenated amorphous silicon, (i)a-Si:H, layers on crystalline silicon, c-Si, within the framework of metal assisted chemical etching (MACE) using silver nanoparticles (Ag NPs). The etching processes are examined by in situ photoluminescence (PL) and in situ surface photovoltage (SPV) measurements, as these techniques allow a monitoring of the hole injection that takes place during MACE. By in situ PL measurements and SEM images, we could interpret the different stages of the MACE process of (i)a-Si:H layers and determine etch rates of (i)a-Si:H, that are found to be influenced by the size of the Ag NPs. In situ PL and in situ SPV measurements both enable researchers to determine when the Ag NPs reach the (i)a-Si:H/c-Si interface. Furthermore, a preferential MACE of (i)a-Si:H versus c-Si is revealed for the first time. This effect could be explained by an interplay of the different thermodynamic and structural properties of the two materials as well as by hole injection during MACE resulting in a field effect passivation. The presented results allow an application of the examined MACE processes for Si nanostructuring applications. PMID:25965159

  10. Potent diarrheagenic mechanism mediated by the cooperative action of three enteropathogenic Escherichia coli-injected effector proteins

    OpenAIRE

    Dean, Paul; Maresca, Marc; Schüller, Stephanie; Phillips, Alan D.; Kenny, Brendan

    2006-01-01

    Enteropathogenic Escherichia coli (EPEC) induces a severe watery diarrhea responsible for several hundred thousand infant deaths each year by a process correlated with the loss (effacement) of absorptive microvilli. Effacement is linked to the locus of enterocyte effacement pathogenicity island that encodes an “injection system,” “effector” proteins, and the Intimin outer membrane protein. Here, we reveal that effacement (i) is a two-step process, (ii) requires the cooperative action of three...

  11. On the mechanisms of cation injection in conducting bridge memories: The case of HfO2 in contact with noble metal anodes (Au, Cu, Ag)

    Science.gov (United States)

    Saadi, M.; Gonon, P.; Vallée, C.; Mannequin, C.; Grampeix, H.; Jalaguier, E.; Jomni, F.; Bsiesy, A.

    2016-03-01

    Resistance switching is studied in HfO2 as a function of the anode metal (Au, Cu, and Ag) in view of its application to resistive memories (resistive random access memories, RRAM). Current-voltage (I-V) and current-time (I-t) characteristics are presented. For Au anodes, resistance transition is controlled by oxygen vacancies (oxygen-based resistive random access memory, OxRRAM). For Ag anodes, resistance switching is governed by cation injection (Conducting Bridge random access memory, CBRAM). Cu anodes lead to an intermediate case. I-t experiments are shown to be a valuable tool to distinguish between OxRRAM and CBRAM behaviors. A model is proposed to explain the high-to-low resistance transition in CBRAMs. The model is based on the theory of low-temperature oxidation of metals (Cabrera-Mott theory). Upon electron injection, oxygen vacancies and oxygen ions are generated in the oxide. Oxygen ions are drifted to the anode, and an interfacial oxide is formed at the HfO2/anode interface. If oxygen ion mobility is low in the interfacial oxide, a negative space charge builds-up at the HfO2/oxide interface. This negative space charge is the source of a strong electric field across the interfacial oxide thickness, which pulls out cations from the anode (CBRAM case). Inversely, if oxygen ions migration through the interfacial oxide is important (or if the anode does not oxidize such as Au), bulk oxygen vacancies govern resistance transition (OxRRAM case).

  12. Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Changjie; Zhu, Huili, E-mail: hlzhu@jmu.edu.cn [Department of Physics, School of Science, Jimei University, Xiamen 361021 (China); Yang, Weihuang [Division of Physics and Applied Physics, School of Physical and Mathematical Science, Nanyang Technological University, Singapore 637371 (Singapore)

    2015-06-07

    Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS{sub 2} upon adsorption of various gas molecules (H{sub 2}, O{sub 2}, H{sub 2}O, NH{sub 3}, NO, NO{sub 2}, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the degree of charge transfer between adsorbate and substrate were determined. All evaluated molecules were physisorbed on monolayer WS{sub 2} with a low degree of charge transfer and accept charge from the monolayer, except for NH{sub 3}, which is a charge donor. Band structure calculations showed that the valence and conduction bands of monolayer WS{sub 2} are not significantly altered upon adsorption of H{sub 2}, H{sub 2}O, NH{sub 3}, and CO, whereas the lowest unoccupied molecular orbitals of O{sub 2}, NO, and NO{sub 2} are pinned around the Fermi-level when these molecules are adsorbed on monolayer WS{sub 2}. The phenomenon of Fermi-level pinning was discussed in light of the traditional and orbital mixing charge transfer theories. The impacts of the charge transfer mechanism on Fermi-level pinning were confirmed for the gas molecules adsorbed on monolayer WS{sub 2}. The proposed mechanism governing Fermi-level pinning is applicable to the systems of adsorbates on recently developed two-dimensional materials, such as graphene and transition metal dichalcogenides.

  13. Charge disproportionation without charge transfer in the rare-earth-element nickelates as a possible mechanism for the metal-insulator transition.

    Science.gov (United States)

    Johnston, Steve; Mukherjee, Anamitra; Elfimov, Ilya; Berciu, Mona; Sawatzky, George A

    2014-03-14

    We study a model for the metal-insulator (M-I) transition in the rare-earth-element nickelates RNiO3, based upon a negative charge transfer energy and coupling to a rocksaltlike lattice distortion of the NiO6 octahedra. Using exact diagonalization and the Hartree-Fock approximation we demonstrate that electrons couple strongly to these distortions. For small distortions the system is metallic, with a ground state of predominantly d8L character, where L_ denotes a ligand hole. For sufficiently large distortions (δdNi-O∼0.05-0.10  Å), however, a gap opens at the Fermi energy as the system enters a periodically distorted state alternating along the three crystallographic axes, with (d8L_2)S=0(d8)S=1 character, where S is the total spin. Thus the M-I transition may be viewed as being driven by an internal volume "collapse" where the NiO6 octahedra with two ligand holes shrink around their central Ni, while the remaining octahedra expand accordingly, resulting in the (1/2, 1/2, 1/2) superstructure observed in x-ray diffraction in the insulating phase. This insulating state is an example of charge ordering achieved without any actual movement of the charge. PMID:24679313

  14. The importance of a hot-sequential mechanism in triplet-state formation by charge recombination in reaction centers of bacterial photosynthesis

    International Nuclear Information System (INIS)

    In photosynthesis, pigment-excitation energies in the antenna system produced by light harvesting are transferred among antenna pigments toward the core antenna, where they are captured by the reaction center and initially fixed in the form of a charge separation. Primary charge separation between an oxidized special pair (P+) and a reduced bacteriopheohytin (H-) is occasionally intervened by recombination, and a spin-triplet state (3P*) is formed on P in the bacterial reaction center. The 3P* state is harmful to bio-organisms, inducing the formation of the highly damaging singlet oxygen species. Therefore, understanding the 3P*-formation mechanism is important. The 3P* formation is mediated by a state |m> of intermediate charge separation between P and the accessory chlorophyll, which is located between P and H. It will be shown theoretically in the present work that at room temperature, not only the mechanism of superexchange by quantum-mechanical virtual mediation at |m>, but also a hot-sequential mechanism contributes to the mediation. In the latter, although |m> is produced as a real state, the final state 3P* is quickly formed during thermalization of phonons in the protein matrix in |m>. In the former, the final state is formed more quickly before dephasing-thermalization of phonons in |m>. 3P* is unistep formed from the charge-separated state in the both mechanisms

  15. Novel Principles and the Charge-Symmetric Design of Dirac's Quantum Mechanics: I. Enhanced Eriksen's Theorem and the Universal Charge-Index Formalism for Dirac's Equation in (Strong) External Static Fields

    Science.gov (United States)

    Kononets, Yu. V.

    2016-07-01

    The presented enhanced version of Eriksen's theorem defines an universal transform of the Foldy-Wouthuysen type and in any external static electromagnetic field (ESEMF) reveals a discrete symmetry of Dirac's equation (DE), responsible for existence of a highly influential conserved quantum number—the charge index distinguishing two branches of DE spectrum. It launches the charge-index formalism (CIF) obeying the charge-index conservation law (CICL). Via its unique ability to manipulate each spectrum branch independently, the CIF creates a perfect charge-symmetric architecture of Dirac's quantum mechanics (DQM), which resolves all the riddles of the standard DE theory (SDET). Besides the abstract CIF algebra, the paper discusses: (1) the novel accurate charge-symmetric definition of the electric-current density; (2) DE in the true-particle representation, where electrons and positrons coexist on equal footing; (3) flawless "natural" scheme of second quantization; and (4) new physical grounds for the Fermi-Dirac statistics. As a fundamental quantum law, the CICL originates from the kinetic-energy sign conservation and leads to a novel single-particle physics in strong-field situations. Prohibiting Klein's tunneling (KT) in Klein's zone via the CICL, the precise CIF algebra defines a new class of weakly singular DE solutions, strictly confined in the coordinate space and experiencing the total reflection from the potential barrier.

  16. Competition between the barrier and injection mechanisms of nonlinearity of the current-voltage characteristic in Mott-barrier detector diodes

    Science.gov (United States)

    Shashkin, V. I.; Vostokov, N. V.

    2009-08-01

    We obtain an analytical solution to the problem of transverse injection current in an undoped semiconductor i layer of arbitrary thickness with account of self-consistent boundary conditions. Charge transfer in the semiconductor bulk is described in the drift-diffusion approximation. Current transfer through the boundaries of an undoped layer is described in terms of the thermoelectron emission theory. Thus, the generalized thermoemission-diffusion approach applies for semiconductors with both low and high mobilities of charge carriers. On the basis of the obtained solution, we analyze the characteristics of the current nonlinearity of the Mott-barrier diodes. The generalized approach is used for describing current transfer in low-barrier diodes based on Mott contacts with near-surface δ-doping. Characteristics of detection of low-barrier diodes are analyzed. Limiting values of the volt-watt and threshold sensitivities of the detectors based on these diodes in the subterahertz frequency range (up to 1 THz) are determined.

  17. Spin injection into semiconductors

    Science.gov (United States)

    Oestreich, M.; Hübner, J.; Hägele, D.; Klar, P. J.; Heimbrodt, W.; Rühle, W. W.; Ashenford, D. E.; Lunn, B.

    1999-03-01

    The injection of spin-polarized electrons is presently one of the major challenges in semiconductor spin electronics. We propose and demonstrate a most efficient spin injection using diluted magnetic semiconductors as spin aligners. Time-resolved photoluminescence with a Cd0.98Mn0.02Te/CdTe structure proves the feasibility of the spin-alignment mechanism.

  18. Improved silicon carbide for advanced heat engines. II - Pressureless sintering and mechanical properties of injection molded silicon carbide

    Science.gov (United States)

    Whalen, Thomas J.; Baer, J. R.

    1989-01-01

    The influence on density and strength of pressureless sintering in vacuum and argon environments has been evaluated with injection molded SiC materials. Main effects and two factor interactions of sintering (cycle variables temperature, time, heating rate, and atmosphere) were assessed. An improved understanding of the influence of the processing flaws and sintering conditions has been obtained. Strength and density have improved from a baseline level of 299 MPa (43.3 Ksi) and 94 pct of theoretical density to values greater than 483 MPa (70 Ksi) and 97 pct.

  19. Effect of Zr, Nb and Ti addition on injection molded 316L stainless steel for bio-applications: Mechanical, electrochemical and biocompatibility properties.

    Science.gov (United States)

    Gulsoy, H Ozkan; Pazarlioglu, Serdar; Gulsoy, Nagihan; Gundede, Busra; Mutlu, Ozal

    2015-11-01

    The research investigated the effect of Zr, Nb and Ti additions on mechanical, electrochemical properties and biocompatibility of injection molded 316L stainless steel. Addition of elemental powder is promoted to get high performance of sintered 316L stainless steels. The amount of additive powder plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders used with the elemental Zr, Nb and Ti powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperatures. The debinded samples were sintered at 1350°C for 60 min. Mechanical, electrochemical property and biocompatibility of the sintered samples were performed mechanical, electrochemical, SBF immersion tests and cell culture experiments. Results of study showed that sintered 316L and 316L with additives samples exhibited high corrosion properties and biocompatibility in a physiological environment. PMID:26275484

  20. Thermo-mechanical Analysis of Cold Helium Injection into Gas Storage Tanks made of Carbon Steel Following Resistive Transition of the LHC Magnets

    CERN Document Server

    Chorowski, M

    1998-01-01

    A resistive transition (quench) of the LHC sector magnets will be followed by cold helium venting to a quench buffer volume of 2000 m3 at ambient temperature. The volume will be composed of eight medi um-pressure (2 MPa) gas storage tanks made of carbon steel, which constrains the temperature of the wall to be higher than -50oC (223 K). The aim of the analysis is the assessment of a possible spot c ooling intensity and thermo-mechanical stresses in the tank wall following helium injection.

  1. Effect of zinc-containing β-tricalcium phosphate nano particles injection on jawbone mineral density and mechanical strength of osteoporosis model rats

    International Nuclear Information System (INIS)

    Zinc-containing β-tricalcium phosphate (ZnTCP) nano particles were injected into zinc-deficient rats to promote osteogenesis. Sprague-Dawley (SD) rats (4 weeks old, average weight of 70 g) were divided into four groups: Normal rats (not ovariectomized (OVX)), Control rats (OVX), and OVX rats injected with a suspension of ZnTCP nano particles or ZnSO4. The ZnTCP contained 6.17% zinc. The suspensions (0.6 mg as a zinc volume/0.2 ml) were injected around the jaw bone once a week for 12 weeks. Local effects on the bone mineral content (BMC) of jawbone, and systemic effects on body weight, the BMC of both femurs determined by X-ray computed tomography, and bone mechanical strength (BMS) measured by the three-point bending method, were examined. The BMC of jaw bone was significantly higher in the ZnTCP-treated group than un-treated or ZnSO4-treated group. Body weight, the BMC of femurs, and BMS were also significantly higher in the ZnTCP treated-group. The zinc-containing β-tricalcium phosphate nano particles were effective at preventing bone loss induced by ovariectomy in rats and have potential uses for treating periodontitis. (author)

  2. Ionic charge state measurements in solar energetic particle events

    International Nuclear Information System (INIS)

    With the launch of the Advanced Composition Explorer, it has become possible through the SEPICA instrument to make direct ionic charge state measurements for individual Solar Energetic Particle events. In large events, the charge state may even be measured as a function of time, revealing changes that may be created by phenomena such as injections from different acceleration mechanisms, or confinement by magnetic field structures. The charge state can be a sensitive indicator of separate SEP populations. Several examples of SEP events will be presented. One of these, the November, 1997 event, displayed a trend in which the mean charge state for several ions increased with energy. These measurements may be the result of several processes, including a mixture of plasma with different source and acceleration histories, and abundance formation and possibly additional charge state modification by collisional or other means in the corona. A wide range of iron charge states have been measured for a variety of SEP events, ranging from =10+ to 20+. The mean charge states of C, O, Ne, Mg and Si all increased as the iron charge state increased. In events with the highest iron charge states, there were abundance enhancements in Ne with respect to oxygen in those cases, even though the mass/charge of the O and Ne were similar. In events with the lowest iron charge states, all these ions except Mg showed mean charge states generally consistent with coronal material of an equilibrium temperature of 1.3-1.6 million degrees K

  3. Decay of electric charge on corona charged polyethylene

    International Nuclear Information System (INIS)

    This paper describes a study on the surface potential decay of corona charged low density polyethylene (LDPE) films. A conventional corona charging process is used to deposit charge on the surface of film and surface potential is measured by a compact JCI 140 static monitor. The results from corona charged multilayer sample reveal that the bulk process dominates charge decay. In addition, the pulsed-electro-acoustic (PEA) technique has been employed to monitor charge profiles in corona charged LDPE films. By using the PEA technique, we are able to monitor charge migration through the bulk. Charge profiles in corona charged multilayer sample are consistent with surface potential results. Of further significance, the charge profiles clearly demonstrate that double injection has taken place in corona charged LDPE films

  4. A study on the shielding mechanisms of SOI pixel detector

    OpenAIRE

    Lu, Yunpeng; Liu, Yi; Wu, Zhigang; Ouyang, Qun; Arai, Yasuo

    2015-01-01

    In order to tackle the charge injection issue that had perplexed the counting type SOI pixel for years, two successive chips CPIXTEG3 and CPIXTEG3b were developed utilizing two shielding mechanisms, Nested-well and Double-SOI, in the LAPIS process. A TCAD simulation showed the shielding effectiveness influenced by the high sheet resistance of shielding layers. Test structures specially designed to measure the crosstalk associated to charge injection were implemented in CPIXTEG3/3b. Measuremen...

  5. Effect of the Residual Deformation on the Mechanical Behavior of the Ni-Ti Alloy Charged by Hydrogen

    International Nuclear Information System (INIS)

    Because of its good corrosion resistance and biocompatibility, super elastic Ni-Ti wire alloys have been successfully used in orthodontic clinics. However, delayed fracture in the oral cavity has been observed. The susceptibility of a Ni-Ti shape memory alloy towards hydrogen embrittlement has been examined with respect to the residual stress after a few numbers of cycles and ageing in air at room temperature. Orthodontic wires have been cathodically charged by hydrogen with a current density of 10 A/m2 from 4h in 0.9% NaCl aqueous solution at room temperature. The critical stress for the martensite transformation under a monotonous tensile test of the as-charged specimen has been 30 MPa higher than that without hydrogen charging. However, after 1 to 50 cycles followed by hydrogen charging, the austenite-martensite plateau is decreased outstandingly compared to the monotonous tensile test of the as-charged by hydrogen specimen. Moreover, compared to the non-cycled and hydrogen charged material, the cyclic deformed and charged by hydrogen specimens present an increase of the initial stress for inducing martensite structure. This increase is about 110 MPa after 50 cycles. In addition, an embrittlement has been detected for the specimen submitted to 50 cycles and hydrogen charging for 4h. This behavior is attributed to the generated dislocations during cyclic deformation which act as trapping sites of hydrogen and a barrier for the austenite-martensite transformation. (author)

  6. Teduglutide Injection

    Science.gov (United States)

    Teduglutide injection is used to treat short bowel syndrome in people who need additional nutrition or fluids from intravenous (IV) therapy. Teduglutide injection is in a class of medications called ...

  7. Levofloxacin Injection

    Science.gov (United States)

    Levofloxacin injection is used to treat infections such as pneumonia; chronic bronchitis; and sinus, urinary tract, kidney, prostate (a male reproductive gland), and skin infections. Levofloxacin injection is also used to prevent anthrax (a ...

  8. Estrogen Injection

    Science.gov (United States)

    The estradiol cypionate and estradiol valerate forms of estrogen injection are used to treat hot flushes (hot ... should consider a different treatment. These forms of estrogen injection are also sometimes used to treat the ...

  9. Ziprasidone Injection

    Science.gov (United States)

    ... of interest in life, and strong or inappropriate emotions). Ziprasidone is in a class of medications called ... alcoholic beverages while you are receiving ziprasidone injection. Alcohol can make the side effects from ziprasidone injection ...

  10. Leucovorin Injection

    Science.gov (United States)

    ... injection is used to prevent harmful effects of methotrexate (Rheumatrex, Trexall; cancer chemotherapy medication) when methotrexate is used to to treat certain types of cancer. Leucovorin injection is used to treat people who ...

  11. Paclitaxel Injection

    Science.gov (United States)

    Paclitaxel injection manufactured with human albumin is used to treat breast cancer that has not improved or ... has come back after treatment with other medications. Paclitaxel injection manufactured with polyoxyethylated castor oil is used ...

  12. Denosumab Injection

    Science.gov (United States)

    ... injection is in a class of medications called RANK ligand inhibitors. It works by decreasing bone breakdown ... months. When denosumab injection (Xgeva) is used to reduce fractures from cancer that has spread to the ...

  13. Sumatriptan Injection

    Science.gov (United States)

    ... the brain, and blocking the release of certain natural substances that cause pain, nausea, and other symptoms ... or upper arm. Do not inject sumatriptan through clothing. Never inject sumatriptan into a vein or muscle. ...

  14. Dexamethasone Injection

    Science.gov (United States)

    Dexamethasone injection is used to treat severe allergic reactions. It is used in the management of certain ... tissues,) gastrointestinal disease, and certain types of arthritis. Dexamethasone injection is also used for diagnostic testing. Dexamethasone ...

  15. Ferumoxytol Injection

    Science.gov (United States)

    Ferumoxytol injection is used to treat iron-deficiency anemia (a lower than normal number of red blood ... are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while receiving ferumoxytol injection, ...

  16. Golimumab Injection

    Science.gov (United States)

    ... appears damaged, and do not use an auto-injection device if the security seal is broken. Look through the viewing window on the prefilled syringe or auto-injection device. The liquid inside should be clear and ...

  17. Cyclosporine Injection

    Science.gov (United States)

    ... injection is used with other medications to prevent transplant rejection (attack of the transplanted organ by the immune system of the person receiving the organ) in people who have received kidney, liver, and heart transplants. Cyclosporine injection should only ...

  18. Doxycycline Injection

    Science.gov (United States)

    Doxycycline injection is used to treat or prevent bacterial infections, including pneumonia and other respiratory tract infections. ... certain skin, genital, intestine, and urinary system infections. Doxycycline injection may be used to treat or prevent ...

  19. Efficient charge injection from the S2 photoexcited state of special-pair mimic porphyrin assemblies anchored on a titanium-modified ITO anode.

    Science.gov (United States)

    Morisue, Mitsuhiko; Haruta, Noriko; Kalita, Dipak; Kobuke, Yoshiaki

    2006-10-25

    A novel surface fabrication methodology has been accomplished, aimed at efficient anodic photocurrent generation by a photoexcited porphyrin on an ITO (indium-tin oxide) electrode. The ITO electrode was submitted to a surface sol-gel process with titanium n-butoxide in order to deposit a titanium monolayer. Subsequently, porphyrins were assembled as monolayers on the titanium-treated ITO surface via phosphonate, isophthalate, and thiolate groups. Slipped-cofacial porphyrin dimers, the so-called artificial special pair at the photoreaction center, were organized through imidazolyl-to-zinc complementary coordination of imidazolylporphyrinatozinc(II) units, which were covalently immobilized by ring-closing olefin metathesis of allyl side chains. The modified surfaces were analyzed by means of X-ray photoelectron spectroscopy. Photoirradiation of the porphyrin dimer generated a large anodic photocurrent in aqueous electrolyte solution containing hydroquinone as an electron sacrificer, due to the small reorganization energy of the dimer. The use of different linker groups led to significant differences in the efficiencies of anodic photocurrent generation. The apparent flat-band potentials evaluated from the photocurrent properties at various pH values and under biased conditions imply that the band structure of the ITO electrode is modified by the anchoring species. The quantum yield for the anodic photocurrent generation by photoexcitation at the Soret band is increased to 15 %, a surprisingly high value without a redox cascade structure on the ITO electrode surface, while excitation at the Q band is not so significant. Extensive exploration of the photocurrent properties has revealed that hot injection of the photoexcited electron from the S2 level into the conduction band of the ITO electrode takes place before internal conversion to the S1* state, through the strong electronic communication of the phosphonyl anchor with the sol-gel-modified ITO surface. PMID

  20. 36-MeV-triton-induced charge exchange: Mass measurements and energy levels of neutron-rich nuclei and the charge exchange reaction mechanism

    International Nuclear Information System (INIS)

    Energy spectra and differential cross sections have been obtained for the charge exchange reaction (3H,3He) on targets of /sup 30,28/Si and /sup 26/Mg at an incident energy of 36 MeV. Previously unobserved energy levels of /sup 30/Al and /sup 26/Na are reported and compared to shell model predictions. Microscopic form factors based on the M3Y effective nucleon-nucleon interaction are used in distorted-wave Born approximation codes to fit the data. The sensitivity of the model to input parameters is discussed and some spin assignments made. Coupled channels calculations are performed to fit the two-step contributions to the data via sequential one-nucleon transfers

  1. Subcutaneous Injections

    DEFF Research Database (Denmark)

    Thomsen, Maria

    at the injection site was influenced by the needle length and the injected volume. Several imaging analysis tools were optimized for the characterization, and these tools were implemented also on subcutaneous injections in rats, visualized by low dose μCT, and used for characterization of the morphology in mouse...

  2. DNA远距离电荷传输机制研究进展述论%Research Evolvement of Mechanisms for Long-range DNA Charge Transport

    Institute of Scientific and Technical Information of China (English)

    牛静; 崔运启

    2011-01-01

    Research about mechanisms for DNA charge transport has received considerable attention by researchers.Various factors can affect the long-range DNA charge transport in solution.In this paper,these factors are introduced briefly and current proposed are summarized.%分析了影响DNA电荷传输的因素,阐述了DNA中电荷传输的各种机制,认为DNA分子中任何一种构象都能形成多种电荷传输途径,条件的改变会导致DNA调节电荷传输的机制发生变化.

  3. Large-scale atomistic and quantum-mechanical simulations of a Nafion membrane: Morphology, proton solvation and charge transport

    Directory of Open Access Journals (Sweden)

    Pavel V. Komarov

    2013-09-01

    Full Text Available Atomistic and first-principles molecular dynamics simulations are employed to investigate the structure formation in a hydrated Nafion membrane and the solvation and transport of protons in the water channel of the membrane. For the water/Nafion systems containing more than 4 million atoms, it is found that the observed microphase-segregated morphology can be classified as bicontinuous: both majority (hydrophobic and minority (hydrophilic subphases are 3D continuous and organized in an irregular ordered pattern, which is largely similar to that known for a bicontinuous double-diamond structure. The characteristic size of the connected hydrophilic channels is about 25–50 Å, depending on the water content. A thermodynamic decomposition of the potential of mean force and the calculated spectral densities of the hindered translational motions of cations reveal that ion association observed with decreasing temperature is largely an entropic effect related to the loss of low-frequency modes. Based on the results from the atomistic simulation of the morphology of Nafion, we developed a realistic model of ion-conducting hydrophilic channel within the Nafion membrane and studied it with quantum molecular dynamics. The extensive 120 ps-long density functional theory (DFT-based simulations of charge migration in the 1200-atom model of the nanochannel consisting of Nafion chains and water molecules allowed us to observe the bimodality of the van Hove autocorrelation function, which provides the direct evidence of the Grotthuss bond-exchange (hopping mechanism as a significant contributor to the proton conductivity.

  4. H2S and CO2 generation mechanisms on a steam injection project on Petrocedeno Field, Orinoco belt.

    Energy Technology Data Exchange (ETDEWEB)

    Uzcategui, D. [PDVSA, Petrocedeno (Venezuela); Lamoureux-Var, V (IFP-Energies nouvelles (France)); Berger, E. (PDVSA Petrocedeno seconded by TOTAL (France))

    2011-07-01

    The Petrocedeno field situated in the Orinoco oil belt, Venezuela contains high volumes of extra heavy oil. Due to the oil's nature, the recovery factor is low and an enhanced oil recovery (EOR) Pilot Project is underway to determine how continuous steam injection techniques could improve the recovery. The aim of this paper is to present this project and the experiments carried out to study the H2S and CO2 generation. Characterization of different oil sand cores from the EOR pilot area was conducted as well as aquathermolysis experiments in IFPEn laboratories to reproduce the contact between reservoir rocks and steam. Results showed an important production of both CO2 and H2S, and determined that H2S is mainly generated by heavy oil while the matrix could be the main source for CO2 generation. This study determined the sources of H2S and CO2 generation and its results were used in the design of Petrocedeno EOR project.

  5. Mechanisms behind injecting the combination of nano-clay particles and polymer solution for enhanced oil recovery

    Science.gov (United States)

    Khalili Nezhad, Seyyed Shahram; Cheraghian, Goshtasp

    2016-08-01

    Laboratory investigations and field applications have proved injection of polymer solution to be an effective means to improve oil recovery for reservoirs of medium oil viscosity. The incremental oil produced in this case is the result of an increase in areal and vertical sweep efficiencies. Biopolymers and synthetic polymers are the major categories used in the petroleum industry for specific reasons. Biopolymers like xanthan are limited in their application as they are more susceptible to biodegradation. Synthetic polymers like Hydrolyzed PolyAcrylaMide (HPAM) have a much wider application as they are less susceptible to biodegradation. Furthermore, development of nanotechnology has successfully provided technical and economical viable alternatives for present materials. The objective of this study is to investigate the effect of combining clay nanoparticles with polymer solution on oil recovery. This paper includes a history match of both one-dimensional and two-dimensional polymer floods using a three-dimensional numerical model for fluid flow and mass transport. Results indicated that the amount of polymer adsorption decreased when clay nanoparticles were added to the PolyAcrylaMide solution; however, mobility ratio improvement is believed to be the main contributor for the proposed method in order to enhance much oil recovery compared to xanthan flood and HPAM flood.

  6. Mechanisms behind injecting the combination of nano-clay particles and polymer solution for enhanced oil recovery

    Science.gov (United States)

    Khalili Nezhad, Seyyed Shahram; Cheraghian, Goshtasp

    2015-09-01

    Laboratory investigations and field applications have proved injection of polymer solution to be an effective means to improve oil recovery for reservoirs of medium oil viscosity. The incremental oil produced in this case is the result of an increase in areal and vertical sweep efficiencies. Biopolymers and synthetic polymers are the major categories used in the petroleum industry for specific reasons. Biopolymers like xanthan are limited in their application as they are more susceptible to biodegradation. Synthetic polymers like Hydrolyzed PolyAcrylaMide (HPAM) have a much wider application as they are less susceptible to biodegradation. Furthermore, development of nanotechnology has successfully provided technical and economical viable alternatives for present materials. The objective of this study is to investigate the effect of combining clay nanoparticles with polymer solution on oil recovery. This paper includes a history match of both one-dimensional and two-dimensional polymer floods using a three-dimensional numerical model for fluid flow and mass transport. Results indicated that the amount of polymer adsorption decreased when clay nanoparticles were added to the PolyAcrylaMide solution; however, mobility ratio improvement is believed to be the main contributor for the proposed method in order to enhance much oil recovery compared to xanthan flood and HPAM flood.

  7. Seed-Mediated Hot-Injection Synthesis of Tiny Ag Nanocrystals on Nanoscale Solid Supports and Reaction Mechanism.

    Science.gov (United States)

    Barhoum, Ahmed; Rehan, Mohamed; Rahier, Hubert; Bechelany, Mikhael; Van Assche, Guy

    2016-04-27

    Controlling the size and shape of noble Ag nanocrystals (NCs) is of great interest because of their unique size- and shape-dependent properties, especially below 20 nm, and because of interesting applications in drug delivery, sensing, and catalysis. However, the high surface energy and tendency of these tiny NCs to aggregate deteriorates their unique properties and limits their applications. To avoid the aggregation of Ag NCs and improve their performance, we report a seed-mediated hot injection approach to synthesize highly dispersed tiny Ag NCs on a nanosized solid CaCO3 support. This simple, low-cost, and effective chemical approach allows for synthesizing highly uniform Ag NCs (∼10 nm) on the surface of presynthesized CaCO3 single NCs (∼52 nm) without any aggregation of the Ag NCs. Viscose fibers were coated with the Ag@CaCO3 composite nanoparticles (NPs) produced, as well as with ∼126 nm Ag NPs for reference. The Ag@CaCO3 composite NPs show excellent UV protection and antibacterial activity against Escherichia coli. In addition, they give a satin sheen gold to a dark gold color to the viscose fibers, while the Ag NPs (∼126 nm) result in a silver color. The proposed synthesis approach is highly versatile and applicable for many other noble metals, like Au or Pt. PMID:27025589

  8. Around the laboratories: Dubna: Physics results and progress on bubble chamber techniques; Stanford (SLAC): Operation of a very rapid cycling bubble chamber; Daresbury: Photographs of visitors to the Laboratory; Argonne: Charge exchange injection tests into the ZGS in preparation for a proposed Booster

    CERN Multimedia

    1969-01-01

    Around the laboratories: Dubna: Physics results and progress on bubble chamber techniques; Stanford (SLAC): Operation of a very rapid cycling bubble chamber; Daresbury: Photographs of visitors to the Laboratory; Argonne: Charge exchange injection tests into the ZGS in preparation for a proposed Booster

  9. A novel procedure employing laser ultrasound technique and simplex algorism for the characterization of mechanical and geometrical properties in Zircaloy tubes with different levels of hydrogen charging

    International Nuclear Information System (INIS)

    In this research, a procedure employing a laser ultrasound technique (LUT) and an inversion algorism is reported for nondestructive characterization of mechanical and geometrical properties in Zircaloy tubes with different levels of hydrogen charging. With the LUT, guided acoustic waves are generated to propagate in the Zircaloy tubes and are detected remotely by optical means. By measuring the dispersive wavespeeds followed by the inversion algorism, mechanical properties such as elastic moduli and geometrical property such as wall-thickness of Zircaloy tubes are characterized for different levels of hydrogen charging. Having the advantages of remote, non-contact and point-wise generation/detection, the reported procedure serves as a competitive candidate for the characterization of Zircaloy tubes generally operated in irradiative and temperature-elevated environments.

  10. A novel procedure employing laser ultrasound technique and simplex algorism for the characterization of mechanical and geometrical properties in Zircaloy tubes with different levels of hydrogen charging

    Energy Technology Data Exchange (ETDEWEB)

    Liu, I-Hung, E-mail: t5669007@ntut.edu.t [Graduate Institute of Manufacturing Technology, National Taipei University of Technology, Taipei, Taiwan (China); Yang, Che-Hua, E-mail: chyang@ntut.edu.t [Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, Taipei, Taiwan (China)

    2011-01-01

    In this research, a procedure employing a laser ultrasound technique (LUT) and an inversion algorism is reported for nondestructive characterization of mechanical and geometrical properties in Zircaloy tubes with different levels of hydrogen charging. With the LUT, guided acoustic waves are generated to propagate in the Zircaloy tubes and are detected remotely by optical means. By measuring the dispersive wavespeeds followed by the inversion algorism, mechanical properties such as elastic moduli and geometrical property such as wall-thickness of Zircaloy tubes are characterized for different levels of hydrogen charging. Having the advantages of remote, non-contact and point-wise generation/detection, the reported procedure serves as a competitive candidate for the characterization of Zircaloy tubes generally operated in irradiative and temperature-elevated environments.

  11. Mechanism of charge transport in ligand-capped crystalline CdTe nanoparticles according to surface photovoltaic and photoacoustic results

    International Nuclear Information System (INIS)

    By combining surface photovoltaic and photoacoustic techniques, we probed the photogenerated charge transport channels of 3-mercaptopropionic acid (MPA)- and 2-mercaptoethylamine (MA)-capped crystalline CdTe nanoparticles on illumination with UV-near IR light. The results experimentally confirmed the presence of a CdS shell outside the CdTe core that formed through the self-assembly and decomposition of mercapto ligands during CdTe preparation. The data revealed that the CdS layer was partly responsible for the deexcitation behavior of the photogenerated carriers, which is related to the quantum tunnel effect. Experiments demonstrated that two quantum wells were located at wavelengths of 440 and 500 nm in buried interfacial space-charge regions, whereas the formation of a ligand layer obstructed charge transfer transitions of the core CdTe nanoparticles to a certain extent.

  12. Controllable synthesis of wurtzite Cu(2)ZnSnS(4) nanocrystals by hot-injection approach and growth mechanism studies.

    Science.gov (United States)

    Luo, Qun; Zeng, Yongquan; Chen, Liwei; Ma, Changqi

    2014-08-01

    Wurtzite Cu2 ZnSnS4 (WZ-CZTS) has been controllably synthesized through a hot-injection route. The crystal-growth mechanism of WZ-CZTS has been investigated by using time-dependent XRD patterns, TEM images, and absorption spectra analysis, and revealed that WZ-CZTS nucleated and grew from monoclinic Cu7 S4 nanocrystals through phase transformation of Cu7 S4 to WZ-CZTS within 5 min. The synthesis processes are dependent on precursor concentration, reaction temperature, reaction time, organic ligand, and sulfur source and have been studied in detail. It was revealed that the width of the WZ-CZTS nanocrystals was mainly controlled by the precursor concentration, which determines the diameter of Cu7 S4 . The length could be regulated by the ratio of dodecanethiol (DDT) to oleylamine (OLA) and reaction time. PMID:25044700

  13. Decay of electric charge on corona charged polyethylene

    International Nuclear Information System (INIS)

    In this paper, the surface potential decay of corona-charged low density polyethylene (LDPE) films has been investigated. It has been found that for the same sample thickness the faster decay occurs in the sample with a higher charging voltage. For the same charging voltage, the surface potential in the thinner sample shows rapid decay. Our new evidence from both the surface potential measurement on multilayer samples and space charge measurement suggests the surface potential decay is a bulk limited process. More importantly, space charge measurement indicates double injection has taken place during corona charging process.

  14. Solution-processed high-LUMO-level polymers in n-type organic field-effect transistors: a comparative study as a semiconducting layer, dielectric layer, or charge injection layer

    International Nuclear Information System (INIS)

    In solution-processed organic field-effect transistors (OFETs), the polymers with high level of lowest unoccupied molecular orbitals (LUMOs, > −3.5 eV) are especially susceptible to electron-trapping that causes low electron mobility and strong instability in successive operation. However, the role of high-LUMO-level polymers could be different depending on their locations relative to the semiconductor/insulator interface, or could even possibly benefit the device in some cases. We constructed unconventional polymer heterojunction n-type OFETs to control the location of the same polymer with a high LUMO level, to be in, under, or above the accumulation channel. We found that although the devices with the polymer in the channel suffer from dramatic instability, the same polymer causes much less instability when it acts as a dielectric modification layer or charge injection layer. Especially, it may even improve the device performance in the latter case. This result helps to improve our understanding of the electron-trapping and explore the value of these polymers in OFETs. (invited article)

  15. Integrating candidate metabolites and biochemical factors to elucidate the action mechanism of Xue-sai-tong injection based on (1)H NMR metabolomics.

    Science.gov (United States)

    Jiang, Miaomiao; Zhao, Xiaoping; Wang, Linli; Xu, Lei; Zhang, Yan; Li, Zheng

    2016-07-15

    A strategy of integrating candidate metabolites with crucial biochemical factors was proposed in this study to discover relevant biological functions for interpreting the action mechanism of Traditional Chinese Medicines (TCM). This approach was applied to Xue-Sai-Tong injection (XST) to reveal the action mechanism based on the metabolic response in an ischemia/reperfusion (I/R) rat model by analyzing NMR profile. Partial least squares discriminate analysis (PLS-DA) was used to compare metabolic profiles of serum samples and revealed nine metabolites altered by I/R injury could be restored to normal status (sham-operated group) under the therapy of XST. The pathway enrichment analysis suggested the metabolic changes were mainly involved in pyruvate metabolism, glycolysis, and citrate cycle. The functional roles of the candidate metabolites were further identified by Pearson correlation analysis with the key biochemical factors in serum. The results indicated pyruvate, succinate, acetate and lysine showed significant associations with the oxidative stress factors. Elevated level of pyruvate was found as an essential metabolic response for the major effect of XST against I/R injury by enhancing glycolysis and overcoming the induced reactive oxygen species (ROS). This metabolomics approach provides a better understanding of the mechanisms of TCM and helps to develop a holistic view of TCM efficacy. PMID:26862062

  16. Charge Breeding of Radioactive Ions

    CERN Document Server

    Wenander, F J C

    2013-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

  17. Dynamics of ionization-induced electron injection in the high density regime of laser wakefield acceleration

    International Nuclear Information System (INIS)

    The dynamics of ionization-induced electron injection in high density (∼1.2 × 1019 cm−3) regime of laser wakefield acceleration is investigated by analyzing the betatron X-ray emission. In such high density operation, the laser normalized vector potential exceeds the injection-thresholds of both ionization-injection and self-injection due to self-focusing. In this regime, direct experimental evidence of early on-set of ionization-induced injection into the plasma wave is given by mapping the X-ray emission zone inside the plasma. Particle-In-Cell simulations show that this early on-set of ionization-induced injection, due to its lower trapping threshold, suppresses the trapping of self-injected electrons. A comparative study of the electron and X-ray properties is performed for both self-injection and ionization-induced injection. An increase of X-ray fluence by at least a factor of two is observed in the case of ionization-induced injection due to increased trapped charge compared to self-injection mechanism

  18. Dexamethasone Injection

    Science.gov (United States)

    ... lines under the skin skin depressions at the injection site increased body fat or movement to different areas of your body inappropriate happiness difficulty falling asleep or staying asleep extreme ... increased appetite injection site pain or redness Some side effects can ...

  19. Paliperidone Injection

    Science.gov (United States)

    Paliperidone extended-release injections (Invega® Sustenna, Invega® Trinza) are used to treat schizophrenia (a mental illness that ... interest in life, and strong or inappropriate emotions). Paliperidone extended-release injection (Invega® Sustenna) is also used ...

  20. Charge Breeding of Radioactive Ions

    OpenAIRE

    Wenander, F. J. C.

    2014-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the phy...

  1. Numerical Analysis on Non-Equilibrium Mechanism of Laser-Supported Detonation Wave Using Multiply-Charged Ionization

    International Nuclear Information System (INIS)

    Laser-Supported Detonation (LSD), one type of Laser-Supported Plasma (LSP), is considered as the most important phenomena because it can generate high pressure and high temperature for laser absorption. In this study, I have numerically simulated the 1-D LSD waves propagating through a helium gas, in which Multiply-charged ionization model is considered for describing an accurate ionization process

  2. Transient analysis of charging system with centrifugal charging pumps

    International Nuclear Information System (INIS)

    The CARD (CVCS Analysis for Design) code has been developed for the transient analysis of the letdown and charging system of Korea Standard Nuclear Power Plant. The computer code has been already verified and validated by comparing with actual test results. Analyzed in this paper are the flow and pressure transients in the charging line. The sensitivity studies are performed to select the acceptable control parameters of charging line backpressure controller and seal injection flow controller. In addition, the seal injection system transient is evaluated for the pressurizer auxiliary spray operation. It is shown that the charging line backpressure controller control parameters yield a significant effect on the charging system stability. The results obtained from this study will be used to verify the system design and to select the optimum control parameters for the charging system with centrifugal charging pumps

  3. Study of K, L vacancies production mechanisms by X spectrometry in the interaction induced by a few MeV/A charged particles

    International Nuclear Information System (INIS)

    The analysis of different mechanisms producing electronic inner shell vacancies in ion atom collisions at a few MeV/A charged is presented. The mutual influence of nuclear and atomic excitation in the ionization probability has been discussed. The 106Cd(p,p')106Cd reaction (Ep=10 MeV) has been particularly investigated from this point. The investigation is followed up by the description of the theoretical and experimental methods which permit the determination of the total and/or differential X rays production cross section for different interaction. The gold sub-shell L1, L2, L3 ionization probability has been studied in the Au(H+,H+)Au reaction at Ep=1 MeV. In the second part of the manuscript we investigate in detail the influence of the charge exchange process on inner shell vacancy production. The N2, Ar, Kr targets have been produced by a system jet gas and bombarded by 0.828Si14+ ions at E=125 MeV. The cross section for the capture of an electron in K shell, L shell and total charge exchange have been measured and compared to the CDW theory (Continuum Distorted Wave). In the CDW validity domain the experimental and theoretical results are a good agreement. In the collisions induced by H+, ionization is found to be the main excitation process. On the contrary, in collisions induced by 28Si14+ charge exchange is dominant compared to ionization

  4. Performance of hybrid p-type vertical transistors with poly(N-vinylcarbazole) as emitter and the transfer mechanism of charge carriers through the base

    International Nuclear Information System (INIS)

    We report hybrid vertical architecture p-type transistors with poly(N-vinylcarbazole) as the emitter, p-type silicon as the collector and Al:Ca alloy layer as the base. The investigation of the common-base and common-emitter characteristics clearly demonstrates that the devices operate as permeable-base transistors (PBTs). The PBTs show common-base current gain α of 0.98 at −VBC = 1.5 V and common-emitter gain β of over 100. Atomic force microscope images of the base layer show an uneven surface, showing that the annealing does not dissolve the charge trap states but offers ‘pinholes’ for the oxidation in-depth even through the whole base layer. In this case, the charge carriers must tunnel the thin oxidized layer, and then are collected. It is clearly seen that there exists a barrier against holes injection from the base to the collector semiconductor at the interface, and the further oxidation caused by exposing the devices in air changes the operational mode of the resulting devices from the PBT to the metal-base transistor. (paper)

  5. Dynamical mechanism of charge separation by photoexcited generation of proton-electron pairs in organic molecular systems. A nonadiabatic electron wavepacket dynamics study

    Science.gov (United States)

    Yamamoto, Kentaro; Takatsuka, Kazuo

    2016-08-01

    In this perspective article, we review, along with presenting new results, a series of our theoretical analyses on the excited-state mechanism of charge separation (proton-electron pair creation) relevant to the photoinduced water-splitting reaction (2H2O → 4H+ + 4e- + O2) in organic and biological systems, which quite often includes Mn clusters in various molecular configurations. The present mechanism is conceived to be universal in the triggering process of the photoexcited water splitting dynamics. In other words, any Mn-based catalytic charge separation is quite likely to be initiated according to this mechanism. As computationally tractable yet realistic models, we examine a series of systems generally expressed as X-Mn-OH2⋯A, where X = (OH, Ca(OH)3) and A = (N-methylformamidine, guanidine, imidazole or ammonia cluster) in terms of the theory of nonadiabatic electron wavepacket dynamics. We first find both an electron and a proton are simultaneously transferred to the acceptors through conical intersections upon photoexcitation. In this mechanism, the electron takes different pathways from that of the proton and reaches the densely lying Rydberg-like states of the acceptors in the end, thereby inducing charge separation. Therefore the presence of the Rydberg-like diffused unoccupied states as an electron acceptor is critical for this reaction to proceed. We also have found another crucial nonadiabatic process that deteriorates the efficiency of charge separation by rendering the created pair of proton and electron back to the originally donor site through the states of d-d band originated from Mn atom. Repetition of this process gradually annihilates the created pair of proton and electron in a way different from the usual charge recombination process. We address this dynamics by means of our proposed path-branching representation. The dynamical roles of a doped Ca atom are also uncovered, which are relevant to controlling the pathways of electron

  6. Ionization and excitation of lithium atoms by fast charged particle impact: identification of mechanisms for double K-shell vacancy production as a function of the projectile charge and velocity

    International Nuclear Information System (INIS)

    Ionization and excitation of lithium atoms by fast charged particle impact: identification of mechanisms for double K-shell vacancy production as a function of projectile charge and velocity. Auger electron spectroscopy is used for an experimental investigation of ionization and excitation of lithium atoms by ions (Kr34+ and Ar18+) and electrons at high impact velocities (from 6 to 60 a.u.). In particular, relative contributions of the mechanisms responsible for lithium K-shell ionization-excitation are determined for various projectile charges Zp and velocities vp. A large range of perturbation parameters |Zp|/vp is explored (|Zp|/vp = 0,05 - 0,7 a.u.). From single K-shell excitation results, it appears that the projectile-electron interaction gives mainly rise to a dipole-like transition 1s -> np Concerning K-shell ionization-excitation, the separation of the TS2 (two independent projectile-electron interactions) and TS1 (one projectile-electron interaction) mechanisms responsible for the formation of the 2snp 1,3P and 2sns 1,3S lithium states is performed. In TS1 process, the projectile-electron interaction can be followed by an electron-electron interaction (dielectronic process) or by an internal rearrangement of the residual target after a sudden potential change (shake process). From Born theory, ab initio calculations are performed. The good agreement between theoretical and experimental results confirms the mechanism identification. For the production of P states, TS1 is found to be strongly dominant for small |Zp|/vp values and TS2 is found to be most important for large |Zp|/vp values. Since P states cannot be formed significantly via a shake process, the TS1 and TS2 separation provides a direct signature of the dielectronic process. On the other hand, the TS1 process is shown to be the unique process for producing the S states. At the moment, only the shake aspect of the TS1 process can explain the fact that the 2s3s configuration is preferentially

  7. Fabrication of low-cost beta-type Ti-Mn alloys for biomedical applications by metal injection molding process and their mechanical properties.

    Science.gov (United States)

    Santos, Pedro Fernandes; Niinomi, Mitsuo; Liu, Huihong; Cho, Ken; Nakai, Masaaki; Itoh, Yoshinori; Narushima, Takayuki; Ikeda, Masahiko

    2016-06-01

    Titanium and its alloys are suitable for biomedical applications owing to their good mechanical properties and biocompatibility. Beta-type Ti-Mn alloys (8-17 mass% Mn) were fabricated by metal injection molding (MIM) as a potential low cost material for use in biomedical applications. The microstructures and mechanical properties of the alloys were evaluated. For up to 13 mass% Mn, the tensile strength (1162-938MPa) and hardness (308-294HV) of the MIM fabricated alloys are comparable to those of Ti-Mn alloys fabricated by cold crucible levitation melting. Ti-9Mn exhibits the best balance of ultimate tensile strength (1046MPa) and elongation (4.7%) among the tested alloys, and has a Young's modulus of 89GPa. The observed low elongation of the alloys is attributed to the combined effects of high oxygen content, with the presence of interconnected pores and titanium carbides, the formation of which is due to carbon pickup during the debinding process. The elongation and tensile strength of the alloys decrease with increasing Mn content. The Ti-Mn alloys show good compressive properties, with Ti-17Mn showing a compressive 0.2% proof stress of 1034MPa, and a compressive strain of 50%. PMID:26999621

  8. Requirements for charged particle light isotopes reaction data for advanced fuel cycles including two step reaction mechanism

    International Nuclear Information System (INIS)

    Requirements for light charged isotopes nuclear reaction data for advanced fusion fuel cycles are identified. This is performed in the frame of the compilation of charged particle nuclear reaction data. Those reactions are considered which determine the nuclear energy production, burn kinetics, neutron- and radionuclide production among fuel and ash isotopes. Emphasis is put on the fuel p-11B for which a review of the status of existing data is given. Other exotic fuel candidates (e.g. p-6Li) and some exotic reactions occurring in D-3He based fuels are also considered, however in less detail. We conclude that there is a lack of experimental and evaluated data for several important reactions. It is recommended that evaluations be performed, existing ones reexamined, and that they are made easily accessible for the increasing number of researchers studying advanced fuels. (author). 52 refs, 10 figs, 6 tabs

  9. Universal diffusion-limited injection and the hook effect in organic thin-film transistors.

    Science.gov (United States)

    Liu, Chuan; Huseynova, Gunel; Xu, Yong; Long, Dang Xuan; Park, Won-Tae; Liu, Xuying; Minari, Takeo; Noh, Yong-Young

    2016-01-01

    The general form of interfacial contact resistance was derived for organic thin-film transistors (OTFTs) covering various injection mechanisms. Devices with a broad range of materials for contacts, semiconductors, and dielectrics were investigated and the charge injections in staggered OTFTs was found to universally follow the proposed form in the diffusion-limited case, which is signified by the mobility-dependent injection at the metal-semiconductor interfaces. Hence, real ohmic contact can hardly ever be achieved in OTFTs with low carrier concentrations and mobility, and the injection mechanisms include thermionic emission, diffusion, and surface recombination. The non-ohmic injection in OTFTs is manifested by the generally observed hook shape of the output conductance as a function of the drain field. The combined theoretical and experimental results show that interfacial contact resistance generally decreases with carrier mobility, and the injection current is probably determined by the surface recombination rate, which can be promoted by bulk-doping, contact modifications with charge injection layers and dopant layers, and dielectric engineering with high-k dielectric materials. PMID:27440253

  10. Study of a transaugmented two-stage small circular-bore railgun for injection of hypervelocity hydrogen pellets as a fusion reactor refueling mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Tompkins, M.W.; Anderson, M.A.; Feng, Q.; Zhang, J.; Kim, K. [Univ. of Illinois, Urbana, IL (United States)

    1997-01-01

    Injection of hypervelocity hydrogen pellets has become widely accepted as the most effective means of refueling magnetically confined fusion reactors. Pellet velocities on the order of 10 km/s are desired and hydrogen pellet erosion during acceleration must be minimized. It is important to maintain uniform bore surfaces during repetitive shots, implying that, if a railgun is to be used to accelerate the pellets, damage to the sidewalls and rails of the railgun due to local heating must be limited. In order to reduce the amount of power dissipated within the bore and increase the propulsive force generated by the plasma-arc armature while minimizing losses due to pellet, rail, and sidewall ablation, the authors have employed a magnetic field transaugmentation mechanism consisting of a two-turn pulsed electromagnet. The two-stage gun consists of a light-gas gun which accelerates a 4- to 5-mg pellet to a speed around 1.2 km/s and injects it into the plasma-arc armature railgun. Currently, they have achieved a final output velocity for a hydrogen pellet of 2.11 km/s with a time-averaged acceleration of 4,850 km/s{sup 2} using a 58-cm railgun pulsed with a peak rail current of 9.2 kA and 28.0 kA of transaugmentation current. This paper will present a description of the hydrogen-pellet-injector railgun system, a discussion of the data on hydrogen pellet acceleration, and projections for future systems.

  11. Injectable and Self-Healing Dynamic Hydrogels Based on Metal(I)-Thiolate/Disulfide Exchange as Biomaterials with Tunable Mechanical Properties.

    Science.gov (United States)

    Casuso, Pablo; Odriozola, Ibon; Pérez-San Vicente, Adrián; Loinaz, Iraida; Cabañero, Germán; Grande, Hans-Jürgen; Dupin, Damien

    2015-11-01

    Despite numerous strategies involving dynamic covalent bonds to produce self-healing hydrogels with similar frequency-dependent stiffness to native tissues, it remains challenging to use biologically relevant thiol/disulfide exchange to confer such properties to polymeric networks. Herein, we report a new method based on Metal(I) [Au(I) or Ag(I)] capping to protect thiolates from aerial oxidation without preventing thiolate/disulfide exchange. Dynamic hydrogels were readily prepared by injecting simultaneously aqueous solutions of commercially available HAuCl4 and 4-arm thiol-terminated polyethylene glycol [(PEGSH)4], resulting in a network containing a mixture of Au(I)-thiolate (Au-S) and disulfide bonds (SS). While the dynamic properties of the hydrogel were closely dependent on the pH, the mechanical properties could be easily tuned by adjusting (PEGSH)4 concentration and amount of Au-S, as judged by dynamic rheology studies. Permanent Au-S/SS exchange at physiological pH conferred self-healing behavior and frequency-dependent stiffness to the hydrogel. In addition, in vitro studies confirmed that Au-based dynamic material was not cytotoxic to human dermal fibroblasts, demonstrating its potential use as a medical device. Dynamic hydrogels obtained using Ag(I) ions demonstrated that the exchange reaction was not affected by the nature of the Metal(I) capping. Finally, this efficient thiolate capping strategy offers a simple way to produce injectable and self-healing dynamic hydrogels from virtually any thiol-containing polymers. PMID:26418440

  12. Facile fabrication of efficient AgBr-TiO{sub 2} nanoheterostructured photocatalyst for degrading pollutants and its photogenerated charge transfer mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenxin [Key Laboratory of Functional Inorganic Materials Chemistry (Heilongjiang University), Ministry of Education, School of Chemistry and Materials Science, Harbin 150080 (China); Jing, Liqiang, E-mail: Jinglq@hlju.edu.cn [Key Laboratory of Functional Inorganic Materials Chemistry (Heilongjiang University), Ministry of Education, School of Chemistry and Materials Science, Harbin 150080 (China); Qu, Yichun; Luan, Yunbo; Fu, Honggang; Xiao, Yuchen [Key Laboratory of Functional Inorganic Materials Chemistry (Heilongjiang University), Ministry of Education, School of Chemistry and Materials Science, Harbin 150080 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer A microemulsion-like chemical precipitation is developed for AgBr-TiO{sub 2} composite. Black-Right-Pointing-Pointer The composite displays effective charge transfers between AgBr and TiO{sub 2.} Black-Right-Pointing-Pointer A charge transfer mechanism in the AgBr-TiO{sub 2} composite is suggested. Black-Right-Pointing-Pointer The suggested mechanism is responsible for the enhanced photocatalytic activity. - Abstract: A simple microemulsion-like chemical precipitation method has been successfully developed to construct effectively-contacted AgBr-TiO{sub 2} composite. The key of this method is the dual roles of Br{sup -} in the synthetic process, as linkers between cetyltrimethyl ammonium cation surfactants and nanocrystalline anatase TiO{sub 2} in the acidic condition, and as bromine sources to directly produce nanocrystalline AgBr on the surfaces of TiO{sub 2} by chemical precipitation. It is well demonstrated that the as-constructed AgBr-TiO{sub 2} nanoheterostructured composites display effective photogenerated charge transfer between AgBr and TiO{sub 2}, favorable to improve charge separation, by means of the surface photovoltage technique in different atmospheres at the aid of outer electric fields, especially for the transient surface photovoltage technique in air. And also, the Br{sup -} in crystal lattice of AgBr could effectively capture photogenerated holes under illumination. These factors are well responsible for the enhanced activity for photocatalytic degradation of liquid phase aqueous phenol solution and gas phase acetaldehyde under either UV-visible or visible irradiation, and the stability of AgBr in the photocatalytic processes.

  13. Aripiprazole Injection

    Science.gov (United States)

    ... pressure, seizures, difficulty swallowing, a high level of fats (cholesterol and triglycerides) in your blood, or a medical condition that may affect you receiving an injection in your arm or buttocks. Tell your doctor ...

  14. Nafcillin Injection

    Science.gov (United States)

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to nafcillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin, cefdinir, ...

  15. Oxacillin Injection

    Science.gov (United States)

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to oxacillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin, cefdinir, ...

  16. Ampicillin Injection

    Science.gov (United States)

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to ampicillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin (Ancef, ...

  17. Olanzapine Injection

    Science.gov (United States)

    ... of interest in life, and strong or inappropriate emotions). Olanzapine injection is used to treat episodes of ... this medication affects you.you should know that alcohol can add to the drowsiness caused by this ...

  18. Aripiprazole Injection

    Science.gov (United States)

    ... of interest in life, and strong or inappropriate emotions). Aripiprazole injection (Abilify) is used to treat episodes ... street drugs or have overused prescription medication or alcohol or has or has ever had diabetes, obsessive ...

  19. Haloperidol Injection

    Science.gov (United States)

    ... of interest in life, and strong or inappropriate emotions). Haloperidol injection is also used to control motor ... this medication affects you.you should know that alcohol can add to the drowsiness caused by this ...

  20. Testosterone Injection

    Science.gov (United States)

    Testosterone cypionate (Depo-Testosterone), testosterone enanthate (Delatestryl), testosterone undecanoate (Aveed), and testosterone pellet (Testopel) are forms of testosterone injection used to treat symptoms of low testosterone in men who have hypogonadism (a ...

  1. Ketorolac Injection

    Science.gov (United States)

    ... of ketorolac by intravenous (into a vein) or intramuscular (into a muscle) injection in a hospital or ... aspirin) such as ketorolac may have a higher risk of having a heart attack or a stroke ...

  2. Busulfan Injection

    Science.gov (United States)

    ... marrow and cancer cells in preparation for a bone marrow transplant. Busulfan is in a class of medications called ... days (for a total of 16 doses) before bone marrow transplant.Busulfan injection may cause seizures during therapy with ...

  3. Fludarabine Injection

    Science.gov (United States)

    ... also sometimes used to treat non-Hodgkin's lymphoma (NHL; cancer that begins in a type of white ... this medication. You should not plan to have children while receiving fludarabine injection or for at least ...

  4. Gemcitabine Injection

    Science.gov (United States)

    ... with surgery. Gemcitabine is also used to treat cancer of the pancreas that has spread to other parts of the ... 4 weeks. When gemcitabine is used to treat cancer of pancreas it may be injected once every week. The ...

  5. Ixekizumab Injection

    Science.gov (United States)

    ... ixekizumab solution before injecting it. Check that the expiration date has not passed and that the liquid ... fever, sweats, or chills, muscle aches, shortness of breath, warm, red, or painful skin or sores on ...

  6. Tesamorelin Injection

    Science.gov (United States)

    ... is colored, cloudy, contains particles, or if the expiration date on the bottle has passed.Never reuse ... swelling of the face or throat shortness of breath difficulty breathing fast heartbeat dizziness fainting Tesamorelin injection ...

  7. Secukinumab Injection

    Science.gov (United States)

    ... secukinumab solution before injecting it. Check that the expiration date has not passed and that the liquid ... fever, sweats, or chills, muscle aches, shortness of breath, warm, red, or painful skin or sores on ...

  8. Basiliximab Injection

    Science.gov (United States)

    ... used with other medications to prevent immediate transplant rejection (attack of the transplanted organ by the immune system of the person receiving the organ) in people who are receiving kidney transplants. Basiliximab injection is in a class of medications ...

  9. Tacrolimus Injection

    Science.gov (United States)

    ... is used along with other medications to prevent rejection (attack of the transplanted organ by the transplant recipient's immune system) in people who have received kidney, liver, or heart transplants. Tacrolimus injection should only ...

  10. Belatacept Injection

    Science.gov (United States)

    ... used in combination with other medications to prevent rejection (attack of a transplanted organ by the immune system of a person receiving the organ) of kidney transplants. Belatacept injection is in a class of medications ...

  11. Ciprofloxacin Injection

    Science.gov (United States)

    ... described in the IMPORTANT WARNING section, stop using ciprofloxacin injection and call your doctor immediately or get emergency medical help: rash hives itching peeling or blistering of the skin ...

  12. Aflibercept Injection

    Science.gov (United States)

    ... diabetes that can lead to vision loss), and diabetic retinopathy (damage to the eyes caused by diabetes). Aflibercept ... your doctor about how long you should continue treatment with aflibercept injection.

  13. Tacrolimus Injection

    Science.gov (United States)

    ... prescribed for other uses; ask your doctor or pharmacist for more information. ... Before receiving tacrolimus injection,tell your doctor and pharmacist if you are allergic to tacrolimus, any other ...

  14. Basiliximab Injection

    Science.gov (United States)

    ... prescribed for other uses; ask your doctor or pharmacist for more information. ... Ask your pharmacist any questions you have about basiliximab injection.It is important for you to keep a written list of ...

  15. Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms.

    Science.gov (United States)

    Wu, Tianshu; He, Keyu; Ang, Shengjun; Ying, Jiali; Zhang, Shihan; Zhang, Ting; Xue, Yuying; Tang, Meng

    2016-01-01

    With the rapid development of nanotechnology, quantum dots (QDs) as advanced nanotechnology products have been widely used in neuroscience, including basic neurological studies and diagnosis or therapy for neurological disorders, due to their superior optical properties. In recent years, there has been intense concern regarding the toxicity of QDs, with a growing number of studies. However, knowledge of neurotoxic consequences of QDs applied in living organisms is lagging behind their development, even if several studies have attempted to evaluate the toxicity of QDs on neural cells. The aim of this study was to evaluate the adverse effects of intrahippocampal injection in rats of 3-mercaptopropionic acid (MPA)-modified CdTe QDs and underlying mechanisms. First of all, we observed impairments in learning efficiency and spatial memory in the MPA-modified CdTe QD-treated rats by using open-field and Y-maze tests, which could be attributed to pathological changes and disruption of ultrastructure of neurons and synapses in the hippocampus. In order to find the mechanisms causing these effects, transcriptome sequencing (RNA-seq), an advanced technology, was used to gain the potentially molecular targets of MPA-modified CdTe QDs. According to ample data from RNA-seq, we chose the signaling pathways of PI3K-Akt and MPAK-ERK to do a thorough investigation, because they play important roles in synaptic plasticity, long-term potentiation, and spatial memory. The data demonstrated that phosphorylated Akt (p-Akt), p-ERK1/2, and c-FOS signal transductions in the hippocampus of rats were involved in the mechanism underlying spatial learning and memory impairments caused by 3.5 nm MPA-modified CdTe QDs. PMID:27358562

  16. Development and evaluation of P/M processing techniques to improve and control the mechanical properties of metal injection molded parts

    Science.gov (United States)

    Sago, James Alan

    Metal Injection Molding (MIM) is one of the most rapidly growing areas of powder metallurgy (P/M) but the growth of MIM into new markets and more demanding applications is limited by two fundamental barriers, the availability of low cost metal powders and a lack of knowledge and understanding of how mechanical properties, especially toughness, are affected by the many parameters in the MIM process. The goals of this study were to investigate solutions to these challenges for MIM. Mechanical alloying (MA) is a technique which can produce a wide variety of powder compositions in a size range suited to MIM and in smaller batches. However MA typically suffers from low production volumes and long milling times. This study will show that a saucer mill can produce sizable volumes of MA powders in times typically less than an hour. The MA process was also used to produce powders of 17-4PH stainless steel and the NiTi shape memory alloy for a MIM feedstock. This study shows that the MA powder characteristics led to successful MIM processing of parts. Previous studies have shown that the toughness of individual MIM parts can vary widely within a single production run and from one producer to another. In the last part of the study a Design of Experiments (DOE) approach was used to evaluate the effects of MIM processing parameters on the mechanical properties. Analysis of Variance produced mathematical models for Charpy impact toughness, hardness, density, and carbon content. Tensile properties did not produce a good model due to processing problems. The models and recommendations for improving both toughness and reproducibility of toughness are presented.

  17. Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms

    Science.gov (United States)

    Wu, Tianshu; He, Keyu; Ang, Shengjun; Ying, Jiali; Zhang, Shihan; Zhang, Ting; Xue, Yuying; Tang, Meng

    2016-01-01

    With the rapid development of nanotechnology, quantum dots (QDs) as advanced nanotechnology products have been widely used in neuroscience, including basic neurological studies and diagnosis or therapy for neurological disorders, due to their superior optical properties. In recent years, there has been intense concern regarding the toxicity of QDs, with a growing number of studies. However, knowledge of neurotoxic consequences of QDs applied in living organisms is lagging behind their development, even if several studies have attempted to evaluate the toxicity of QDs on neural cells. The aim of this study was to evaluate the adverse effects of intrahippocampal injection in rats of 3-mercaptopropionic acid (MPA)-modified CdTe QDs and underlying mechanisms. First of all, we observed impairments in learning efficiency and spatial memory in the MPA-modified CdTe QD-treated rats by using open-field and Y-maze tests, which could be attributed to pathological changes and disruption of ultrastructure of neurons and synapses in the hippocampus. In order to find the mechanisms causing these effects, transcriptome sequencing (RNA-seq), an advanced technology, was used to gain the potentially molecular targets of MPA-modified CdTe QDs. According to ample data from RNA-seq, we chose the signaling pathways of PI3K–Akt and MPAK–ERK to do a thorough investigation, because they play important roles in synaptic plasticity, long-term potentiation, and spatial memory. The data demonstrated that phosphorylated Akt (p-Akt), p-ERK1/2, and c-FOS signal transductions in the hippocampus of rats were involved in the mechanism underlying spatial learning and memory impairments caused by 3.5 nm MPA-modified CdTe QDs. PMID:27358562

  18. Dynamic Charge Carrier Trapping in Quantum Dot Field Effect Transistors.

    Science.gov (United States)

    Zhang, Yingjie; Chen, Qian; Alivisatos, A Paul; Salmeron, Miquel

    2015-07-01

    Noncrystalline semiconductor materials often exhibit hysteresis in charge transport measurements whose mechanism is largely unknown. Here we study the dynamics of charge injection and transport in PbS quantum dot (QD) monolayers in a field effect transistor (FET). Using Kelvin probe force microscopy, we measured the temporal response of the QDs as the channel material in a FET following step function changes of gate bias. The measurements reveal an exponential decay of mobile carrier density with time constants of 3-5 s for holes and ∼10 s for electrons. An Ohmic behavior, with uniform carrier density, was observed along the channel during the injection and transport processes. These slow, uniform carrier trapping processes are reversible, with time constants that depend critically on the gas environment. We propose that the underlying mechanism is some reversible electrochemical process involving dissociation and diffusion of water and/or oxygen related species. These trapping processes are dynamically activated by the injected charges, in contrast with static electronic traps whose presence is independent of the charge state. Understanding and controlling these processes is important for improving the performance of electronic, optoelectronic, and memory devices based on disordered semiconductors. PMID:26099508

  19. Are adrenaline autoinjectors fit for purpose? A pilot study of the mechanical and injection performance characteristics of a cartridge- versus a syringe-based autoinjector

    Directory of Open Access Journals (Sweden)

    Andreas Schwirtz

    2010-11-01

    Full Text Available Andreas Schwirtz, Harald SeegerPharma Consult GmbH, Vienna, AustriaBackground: Adrenaline autoinjectors (AAIs are prescribed to facilitate the intramuscular administration of adrenaline in patients diagnosed with life-threatening anaphylaxis. This pilot study investigated the injection and functional properties of two AAIs (deploying different delivery systems under standard conditions, after dynamic and mechanical stresses, and in the presence of denim.Methods: The differences between a cartridge-based AAI (EpiPen® Junior and a syringe-based AAI (Anapen® Junior were assessed using three sets of tests. Test 1: under standard conditions, the injection depth and dose were measured in ballistic gelatine (a validated tissue simulant. Test 2: before the safety cap removal and activation forces were measured, AAIs were subjected to either of two preconditioning tests: 1 free-fall drop test; or 2 static load (ie, 400 N, equivalent to 40 kg weight test; or 3 no preconditioning. Test 3: under standard conditions, injection properties into ballistic gelatine in the presence and absence of denim were investigated. Statistical analyses were performed using the Student’s t-test or Welch’s test.Results: The maximum depth of delivery was significantly greater with cartridge AAI (n = 4, mean 21.09 ± 2.54 mm than with syringe AAI (n = 5; mean 11.64 ± 0.80 mm; P = 0.003. After 2.5 seconds, cartridge AAI (n = 4 discharged significantly more dose than syringe AAI (n = 3; 74.3% versus 25.7% of total dose; P = 0.001. Both cartridge and syringe AAI withstood the free-fall drop test, but almost all devices failed to activate following the static load test. Under standard conditions, significantly less force was required to remove the safety cap of cartridge AAI than syringe AAI (both n = 15; mean 9.56 ± 2.36 N versus 20.23 ± 6.61 N, respectively; P < 0.001, but a significantly greater activation force was required for cartridge AAI than syringe AAI (mean 23

  20. The size-dependent charge fraction of sub-3-nm particles as a key diagnostic of competitive nucleation mechanisms under atmospheric conditions

    Science.gov (United States)

    Yu, F.; Turco, R. P.

    2011-09-01

    A clear physical understanding of atmospheric particle nucleation mechanisms is critical in assessing the influences of aerosols on climate and climate variability. Currently, several mechanisms have been proposed and are being employed to interpret field observations of nucleation events. Roughly speaking, the two most likely candidates are neutral cluster nucleation (NCN) and ion-mediated nucleation (IMN). Detailed nucleation event data has been obtained in boreal forests. In one set of analyses of these measurements, NCN was suggested as the dominant formation mode, while in another, it was IMN. Information on the electrical charge distribution carried by the nucleating clusters is one key for identifying the relative contributions of neutral and ion-mediated processes under various conditions. Fortunately, ground-breaking measurements of the charged states or fractions of ambient nanometer-sized particles soon after undergoing nucleation are now available to help resolve the main pathways. In the present study, the size-dependent "apparent" formation rates and fractions of charged and neutral particles in a boreal forest setting are simulated with a detailed kinetic model. We show that the predicted "apparent" formation rates of charged and neutral particles at 2 nm for eight representative case study days agree well with the corresponding values based on observations. In the simulations, the "apparent" contribution of ion-based nucleation increases by up to ~one order of magnitude as the size of "sampled" particles is decreased from 2 nm to ~1.5 nm. These results suggest that most of the neutral particles sampled in the field at sizes around 2 nm are in reality initially formed on ionic cores that are neutralized before the particles grow to this size. Thus, although the apparent rate of formation of neutral 2-nm particles might seem to be dominated by a neutral clustering process, in fact those particles may be largely the result of an ion-induced nucleation

  1. Quadrupolar deformation of the electronic charge cloud and the lattice mechanics of LiH-LiD crystals

    International Nuclear Information System (INIS)

    As the deformable shell model incorporates both scalar and dipolar deformation, it is natural to expect that the quadrupolar deformation may be important in the case of lithium hydride, where the unstable hydrogen ion with its extremely loose bound outermost electron (compared to alkali halides) appears to be a plausible candidate for such deformation. Quadrupolar deformation in an ion in crystal may arise because of the variation of the electric field produced by o,.her ions over the extent of the charge cloud or due to a shortrange overlap effect of nearest neighbours. The second effect is much stronger than the first and this alone is considered in the present investigation. A method has been developed to obtain the relevant equations and evaluate all the lattice sums appropriate for the structure on the basis of an extended deformable shell model which incorporates scalar, dipolar and quadrupolar deformation. The quadrupolar deformation is found to have quite a considerable effect both on the dynamic and static properties of LiH-LiD crystals. The resulting model not only removes the discrepancies mentioned above but has also been successful in correlating the specific properties namely, the static lattice structure, the cohesive energy, the second order elastic constants, the dielectric properties and the lattice dynamics with a single set of parameters used for all of them. Only the shortrange overlap effect of the nearest neighbours has been taken into account and not that due to the variation of the electric field produced by other ions over the extent of charge cloud, since the former effect is much stronger than the latter one. (K.B.)

  2. Discharge/charge reaction mechanisms of FeS2 cathode material for aluminum rechargeable batteries at 55°C

    Science.gov (United States)

    Mori, Takuya; Orikasa, Yuki; Nakanishi, Koji; Kezheng, Chen; Hattori, Masashi; Ohta, Toshiaki; Uchimoto, Yoshiharu

    2016-05-01

    The aluminum rechargeable battery is a desirable device for large-scale energy storage owing to the high capacity derived from the properties of the aluminum metal anode. The development of cathode materials is needed to compose battery systems. However, the design principles of the cathode materials have not been determined. We focus on the high capacity FeS2 cathode materials and investigate the discharge/charge reaction mechanisms in chloroaluminate ionic liquids as the electrolyte at 55°C. X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements are performed for the discharged and charged samples. S 3p-orbitals are shown to play an important role in the redox reactions from the results of the S and Fe K-edge XANES spectra. As a result of the redox reaction, FeS2 is transformed into low crystalline FeS and amorphous Al2S3, as shown by the XRD and S, Al, and Fe K-edge XANES spectra. This reaction mechanism is different from the reaction observed with lithium ion.

  3. Alirocumab Injection

    Science.gov (United States)

    ... feeding. If you become pregnant while using alirocumab injection, call your doctor. ... Eat a low-fat, low-cholesterol diet. Be sure to follow all exercise and dietary ... at: http://www.nhlbi.nih.gov/health/public/heart/chol/chol_tlc.pdf.

  4. Medroxyprogesterone Injection

    Science.gov (United States)

    ... injection when you are a teenager or young adult. Tell your doctor if you or anyone in your family has osteoporosis; if you have or have ever had any other bone disease or anorexia nervosa (an eating disorder); or if you drink a ...

  5. Botox Injections

    Science.gov (United States)

    ... Contact Us Shopping Cart American Academy of Facial Plastic and Reconstructive Surgery Home Meetings & Courses Find a Surgeon Physicians’ Buyers ... Portal Botox Injections The American Academy of Facial Plastic and Reconstructive Surgery recommends persons considering Botox® treatment to: Check the ...

  6. Ibritumomab Injection

    Science.gov (United States)

    ... have received ibritumomab injection.do not have any vaccinations without talking to your doctor.you should know ... cells) and myelodysplastic syndrome (condition in which blood cells do not ... online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

  7. Tositumomab Injection

    Science.gov (United States)

    ... have received tositumomab injection.do not have any vaccinations without talking to your doctor.you should know ... blood cells), myelodysplastic syndrome (condition in which blood cells do not ... online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

  8. Oxytocin Injection

    Science.gov (United States)

    ... provider immediately: chest pain or difficulty breathing confusion fast or irregular heartbeat severe headache irritation at the injection site If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting ...

  9. Infliximab Injection

    Science.gov (United States)

    ... injection is also sometimes used to treat Behcet's syndrome (ulcers in the mouth and on the genitals and inflammation of various ... runny nose back pain white patches in the mouth vaginal itching, burning, and pain, or other signs of a yeast ...

  10. Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms

    Directory of Open Access Journals (Sweden)

    Wu T

    2016-06-01

    Full Text Available Tianshu Wu,1,2 Keyu He,1,2 Shengjun Ang,1,2 Jiali Ying,1,2 Shihan Zhang,1,2 Ting Zhang,1,2 Yuying Xue,1,2 Meng Tang1,2 1Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, School of Public Health, Collaborative Innovation Center of Suzhou Nano Science and Technology, 2Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing, People’s Republic of China Abstract: With the rapid development of nanotechnology, quantum dots (QDs as advanced nanotechnology products have been widely used in neuroscience, including basic neurological studies and diagnosis or therapy for neurological disorders, due to their superior optical properties. In recent years, there has been intense concern regarding the toxicity of QDs, with a growing number of studies. However, knowledge of neurotoxic consequences of QDs applied in living organisms is lagging behind their development, even if several studies have attempted to evaluate the toxicity of QDs on neural cells. The aim of this study was to evaluate the adverse effects of intrahippocampal injection in rats of 3-mercaptopropionic acid (MPA-modified CdTe QDs and underlying mechanisms. First of all, we observed impairments in learning efficiency and spatial memory in the MPA-modified CdTe QD-treated rats by using open-field and Y-maze tests, which could be attributed to pathological changes and disruption of ultrastructure of neurons and synapses in the hippocampus. In order to find the mechanisms causing these effects, transcriptome sequencing (RNA-seq, an advanced technology, was used to gain the potentially molecular targets of MPA-modified CdTe QDs. According to ample data from RNA-seq, we chose the signaling pathways of PI3K–Akt and MPAK–ERK to do a thorough investigation, because they play important roles in synaptic plasticity, long-term potentiation, and spatial memory. The data demonstrated that phosphorylated Akt (p-Akt, p-ERK1/2, and c-FOS signal

  11. Injection currents in thin disordered organic films

    International Nuclear Information System (INIS)

    Analytic model of barrier-limited injection of charge carriers from metal electrodes into organic film, which was introduced by Arkhipov and co-workers, is modified, considering effects of multiple image charges and injection from both electrodes. Limits of applicability of Arkhipov's model are discussed. Variations from Arkhipov's model are important, if film thickness is comparable with Onsager length

  12. Study of elementary transfer mechanisms during a collision between a swift multi-charged heavy ion and a neutral atom

    International Nuclear Information System (INIS)

    This work is dedicated to the study of the energy transfer mechanisms which occur during a collision between a swift multicharged heavy ion and a neutral atom. The elementary energy energy transfer mechanisms (scattering, excitation, ionization, capture) and their consequences on the target velocity after the collision (recoil velocity) are recalled in the first chapter. In the case of small projectile diffusion angles, we show that the recoil velocity component, transverse to the incident projectile direction, results principally from the diffusion mechanism, while the longitudinal component is due essentially to the mass transfer and the inelastic energy transfer mechanisms. Since the target recoil velocities are very small, we have built an experimental set-up which reduces the impreciseness on their measurement due to the target thermal spread using, as targets, cooled atoms of a supersonic jet (temperature 44+(6.7 MeV/A) + Ar => Xe44 + Arq++qe- (q ranging from 1 to 7); Xe44+ (6.7 MeV/A) + He => Xe44+ He1+,2++1e-,2e-. We show that it is possible to interpret the recoil velocity in terms of kinetic energy transferred to the target and to the electrons ejected from the target. (author)

  13. Gate-bias controlled charge trapping as a mechanism for NO2 detection with field-effect transistors

    NARCIS (Netherlands)

    Andringa, A.-M.; Meijboom, J.R.; Smits, E.C.P.; Mathijssen, S.G.J.; Blom, P.W.M.; Leeuw, D.M. de

    2011-01-01

    Detection of nitrogen dioxide, NO2, is required to monitor the air-quality for human health and safety. Commercial sensors are typically chemiresistors, however field-effect transistors are being investigated. Although numerous investigations have been reported, the NO2 sensing mechanism is not clea

  14. Impact of Different Vein Catheter Sizes for Mechanical Power Injection in CT: In Vitro Evaluation with Use of a Circulation Phantom

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the influence of different peripheral vein catheter sizes on the injection pressure, flow rate, injection duration, and intravascular contrast enhancement. A flow phantom with a low-pressure venous compartment and a high-pressure arterial compartment simulating physiological circulation parameters was used. High-iodine-concentration contrast medium (370 mg iodine/ml; Ultravist 370) was administered in the venous compartment through peripheral vein catheters of different sizes (14, 16, 18, 20, 22, and 24 G) using a double-head power injector with a pressure limit of 325 psi. The flow rate was set to 5 ml/s, with a total iodine load of 36 g for all protocols. Serial CT scans at the level of the pulmonary artery and the ascending and the descending aorta replica were obtained. The true injection flow rate, injection pressure, injection duration, true contrast material volume, and pressure in the phantom during and after injection were continuously monitored. Time enhancement curves were computed and both pulmonary and aortic peak time and peak enhancement were determined. Using peripheral vein catheters with sizes of 14-20 G, flow rates of approximately 5 ml/s were obtained. During injection through a 22-G catheter the pressure limit was reached and the flow rate was decreased, with a consecutive decreased pulmonary and aortic contrast enhancement compared to the 14- to 20-G catheters. Injection through a 24-G peripheral vein catheter was not possible because of disconnection of the canula due to the high flow rate and pressure. In summary, intravenous catheters with sizes of 14-20 G are suitable for CT angiography using an injection protocol with a high flow rate and a high-iodine-concentration contrast medium.

  15. Study on the distribution sites and the molecular mechanism of analgesia after intracerebroventricular injection of rat/mouse hemokinin-1 in mice.

    Science.gov (United States)

    Xia, Rui-Long; Fu, Cai-Yun; Zhang, Shi-Fu; Jin, Yuan-Ting; Zhao, Fu-Kun

    2013-05-01

    Hemokinin-1 is a peptide encoded by Pptc, which belongs to the family of mammalian tachykinins. Our previous results showed that rat/mouse hemokinin-1 (r/m HK-1) produced striking analgesia after intracerebroventricular (i.c.v.) injection in mice, and the analgesia could be blocked by the NK1 receptor antagonist and the opioid receptor antagonist, respectively. However, the precise distribution sites and the molecular mechanism involved in the analgesic effect after i.c.v. administration of r/m HK-1 are needed to be further investigated deeply. Using the fluorescence labeling method, our present results directly showed that r/m HK-1 peptides were mainly distributed at the ventricular walls and several juxta-ventricular structures for the first time. Our results showed that the mRNA expressions of NK1 receptor, PPT-A, PPT-C, KOR, PDYN, DOR and PENK were not changed markedly, as well as the protein expression of NK1 receptor was hardly changed. However, both the transcripts and proteins of MOR and POMC were up-regulated significantly, indicating that the analgesic effect induced by i.c.v. administration of r/m HK-1 is related to the activation of NK1 receptor first, then it is related to the release of endogenous proopiomelanocortin, as well as the increased expression level of μ opioid receptor. These results should facilitate further the analysis of the analgesia of r/m HK-1 in the central nerval system in acute pain and may open novel pharmacological interventions. PMID:23470255

  16. Analysis of Premixed Charge Compression Ignition Combustion with a Sequential Fluid Mechanics-Multizone Chemical Kinetics Model

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S M; Flowers, D L; Espinosa-Loza, F; Babajimopoulos, A; Assanis, D N

    2004-09-30

    We have developed a methodology for analysis of PCCI engines that applies to conditions in which there is some stratification in the air-fuel distribution inside the cylinder at the time of combustion. Our analysis methodology consists of two stages: first, a fluid mechanics code is used to determine temperature and equivalence ratio distributions as a function of crank angle, assuming motored conditions. The distribution information is then used for grouping the mass in the cylinder into a two-dimensional (temperature-equivalence ratio) array of zones. The zone information is then handed on to a detailed chemical kinetics model that calculates combustion, emissions and engine efficiency information. The methodology applies to situations where chemistry and fluid mechanics are weakly linked. The results of the multi-zone model have been compared to the results obtained from a fully integrated code, in which a chemical kinetics code is directly linked into a fluid mechanics code to calculate chemistry in every cell of the grid. The results show that the multi-zone model predicts burn duration and peak cylinder pressure with good accuracy. However, ignition timing predicted by the multi-zone model is sensitive to the transition angle between the fluid mechanics code and the chemical kinetics code. The paper explores the possibility of using three different criteria for determining the transition angle: fraction of heat release at the time of ignition, temperature of the hottest cell at the time of ignition, and a fixed crank angle of transition. The results show that the three criteria have some validity as transition criteria. Further research is necessary to investigate the effect of fuel properties and operating conditions on transition angle.

  17. Radiation-thermal effects change of physico-mechanical properties in reactor materials irradiated with neutrons and energetic charged particles

    International Nuclear Information System (INIS)

    In the first part of the report (chapter 1) the earlier results of the important scientific and technological investigations which were performed in the seventies years in Poland have been presented. They concerned the fabrication, corrosion, mechanical properties of materials for research and power reactors. Being of the general survey character, the chapter includes own, original results of research of thermal irradiation effects on microstructure evolution phase transformations and mechanical properties of reactor materials. The kinetics of isothermal transformation β→α in U-Cr 0.4% wt. alloy has been studied. Factors affecting stress-corrosion cracking of zirconium in iodine vapour have been investigated. The rings and loops for irradiation specimens and Hot Laboratory for postirradiation examination of construction materials is described. In the second part (chapters 2, 3, 4, 5) performed the investigations and simulations of radiation damage in metals by heavy ion beams (E > 1 MeV/a.m.n.) were described scientific base and technical problems of the method of irradiation of heavy ions and of the examination of irradiated samples is presented. It is followed by a summary of the results of simulation and reactor experiments on different materials. Radiation hardening of a number metals (Al, Zr, Cu, Ni, U) irradiated by heavy ion and neutrons, mechanical properties and microstructural evolution in ion and neutron irradiated austenitic stainless steel is described. The last chapter is a description of practical aspects of the presented studies in nuclear science and technology. (author)

  18. pH-Independent Charge Resonance Mechanism for UV Protective Functions of Shinorine and Related Mycosporine-like Amino Acids.

    Science.gov (United States)

    Matsuyama, Keisuke; Matsumoto, Jun; Yamamoto, Shogo; Nagasaki, Keisuke; Inoue, Yoshihisa; Nishijima, Masaki; Mori, Tadashi

    2015-12-24

    The UV-protective ability of mycosporine-like amino acids (MAAs) has been well documented and is believed to serve as a protecting agent for marine organisms from solar radiation. However, the effective UV absorption by MAAs has not been well correlated to MAA (neutral) structures. In this study, the origin of UV-protecting ability of MAAs was elucidated by experimental and theoretical spectroscopic investigations. The absorption maxima of mycosporine-glycine and shinorine in the UVA region were practically unaffected over a wide range of pH 4-10 and only slightly blue-shifted at pH 1-2. It was revealed that the zwitterionic nature of the amino acid residue facilitates the protonation to the chromophoric 3-aminocyclohexenone and 1-amino-3-iminocyclohexene moieties and the operation of the charge resonance in the protonated species well accounts for their allowed low-energy transitions in the UVA region. The RI-CC2/TZVP calculations on model systems in their protonated forms well reproduced the observed transition energies and oscillator strengths of MAAs, only with insignificant systematic overestimations of the both values. The slight hypsochromic shifts at pH 1-2 were explained by (partial) protonation to a carboxylate anion in the amino acid residue, as confirmed by theory. Fluorescence spectral investigations of shinorine were also performed for the first time in water to confirm the effective nonradiative deactivation. Consequently, this study unequivocally demonstrated that the 3-aminocyclohexenone as well as 1-amino-3-iminocyclohexene moieties, which are readily protonated at a wide range of pH, are responsible for the UV-protective ability of aqueous solution of MAAs. PMID:26625701

  19. Study of the removal mechanism of magnesium from Al-Si liquid alloys using silica base minerals injection; Estudio del mecanismo de eliminacion de magnesio de aleaciones Al-Si en estado liquido mediante inyeccion de minerales base silice

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Arroyo, R.; Escobedo-Bocardo, J. C.; Hernande-Garcia, H. M.; Cortes-Hernandez, D. A.; Terrones-Maldonado, M.; Rodriguez-Pulido, A.; Hernandez-Pinero, J. L.

    2010-07-01

    In order to eliminate magnesium from an A 380 Al-Si alloy at 750 degree centigrade, the submerged powder injection method, using an inert carrier gas (Ar), was applied. The injected powders in the liquid aluminum bath were zeolite, silica and mixtures of zeolite-silica minerals. For each experiment the response variables were: eliminated magnesium versus injection time and quantity of drosses produced. Chemical analysis by atomic absorption spectrometry showed that mixtures of silica-zeolite 66:34 wt% have the best results with regarding to the removal magnesium from 1 to 0.0066 wt%. During the elimination of magnesium complex stoichiometry compounds were formed due to the reactions among zeolite, water steam and liquid aluminum. These compounds were analyzed by XRD, SEM and TEM. The results obtained, along with using the FactSage 6 thermodynamic software, allowed to elucidate the reaction mechanism between the minerals used and liquid aluminum. (Author)

  20. An insight into the mechanism of charge transfer properties of hybrid organic (MEH-PPV): Inorganic (TiO2) nanocomposites

    Science.gov (United States)

    Mittal, Tanu; Tiwari, Sangeeta; Mehta, Aarti; Sharma, Shailesh N.

    2016-04-01

    Now a days, inorganic nanoparticles are gaining importance and are potential candidate in different organic electronic device application like (LEDs, PVs) due to their novel properties and confinement in Nano-dimensions. cm 2] In the present work, we have compared the properties of titanium di oxide (TiO2) nanoparticles (NPs) synthesized by using two different chemical routes aqueous and ethanol respectively. These synthesized TiO2 nanoparticles have been characterized by X-ray diffraction spectroscopy (XRD) for phase confirmation. It was observed that synthesized nanoparticles are in anatase phase for both preparation routes. Morphological information was collected by scanning electron microscopy (SEM) which confirms that particles are almost spherical in shape and distributed uniformly which is further ensured by transmission electron microscopy (TEM). Dynamic light scattering (DLS) technique was also used for further confirmation of size distribution of as-synthesized nanoparticles. Optical properties were also investigated by photoluminescence and UV-Vis spectroscopy and calculated bandgap was found to be in the range of 3.3-3.5eV for TiO2 (aq/eth) nanoparticles. The increase in bandgap values with respect to bulk (3.2 eV) confirms that as- synthesized nanoparticles are confined in nanodimensions. As synthesized nanoparticles were interacted with MEHPPV polymer (donor) matrix to make their respective MEHPPV: TiO2 nanocomposites and to confirm the charge transfer mechanism from polymer to nanoparticles. It can be observed from photoluminescence (PL) quenching experiments that continuous quenching obtained for respective nanocomposites confirms better charge transfer from polymer to inorganic TiO2 nanoparticles respectively. Because of, better quenching and simultaneously enhanced charge transfer of respective nanocomposites, ensures that these nanocomposites are greatly applicable for photovoltaics (PVs) especially in Hybrid Solar cells (HSCs).

  1. Improved solar-driven photocatalytic performance of Ag3PO4/ZnO composites benefiting from enhanced charge separation with a typical Z-scheme mechanism

    Science.gov (United States)

    Zhong, Junbo; Li, Jianzhang; Wang, Tao; Zeng, Jun; Si, Yujun; Cheng, Chaozhu; Li, Minjiao; Wang, Pei; Ding, Jie

    2016-01-01

    In this work, efficient simulated solar-driven Ag3PO4/ZnO photocatalysts with different molar ratios of Ag/Zn have been prepared by a precipitation method and characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy and surface photovoltage (SPV) spectroscopy. Under simulated sunlight illumination, the Ag3PO4/ZnO composites exhibit enhanced photocatalytic activity compared with the pure ZnO toward the decolorization of rhodamine B (RhB) aqueous solution, and the Ag3PO4/ZnO composite with 4 % Ag/Zn molar ratio exhibits the highest activity. The quenching effects of scavengers indicate that O2•- plays the major role in RhB decolorization. Ag3PO4 deposited on the ZnO surface can promote the separation rate of photoinduced charge carriers, proven by the SPV results. Based on all the observations, the charge separation mechanism with a typical Z-scheme was proposed.

  2. Operating and impact of the compensation mechanism of the electric utility charges on the energy offer in non connected areas

    International Nuclear Information System (INIS)

    Since the law of the 10 february 2000 relative to the modernization and the development of the electric utility, the France adopted a mechanism aiming to compensate the costs subjected by EDF and other suppliers providing a public utility mission in the domain of the electricity production and distribution. This document takes stock on the organization, the evaluation and the economical and environmental consequences of the implementing of a compensation system of costs bond to the electricity production in non connected areas. (A.L.B.)

  3. Syringe-injectable electronics

    Science.gov (United States)

    Liu, Jia; Fu, Tian-Ming; Cheng, Zengguang; Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M.

    2015-07-01

    Seamless and minimally invasive three-dimensional interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating the syringe injection (and subsequent unfolding) of sub-micrometre-thick, centimetre-scale macroporous mesh electronics through needles with a diameter as small as 100 μm. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with >90% device yield. We demonstrate several applications of syringe-injectable electronics as a general approach for interpenetrating flexible electronics with three-dimensional structures, including (1) monitoring internal mechanical strains in polymer cavities, (2) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (3) in vivo multiplexed neural recording. Moreover, syringe injection enables the delivery of flexible electronics through a rigid shell, the delivery of large-volume flexible electronics that can fill internal cavities, and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics.

  4. Analysis of charge transfer mechanisms in grazing incidence collisions between He sup + (1s) ions and Al(1 1 1) surfaces

    CERN Document Server

    Gutíerrez, F A; Jequier, S; Jouin, H

    2003-01-01

    We analyze angular distributions of neutralized particles after grazing incidence collisions between slow He sup + (1s) ions and Al(1 1 1) surfaces by application of a numerical code which can include all the relevant charge exchange mechanisms. Our analysis is based on comparisons between calculated angular distributions of scattered species and experimental data for two different representations of the image potentials. We found that angular distributions produced by the collective surface-plasmon mode of ion neutralization are consistent in peak's position and angular range with the experimental results. The high of the calculated angular distribution is below the experimental one which indicates the need to consider the electron-hole excitation mode and possibly some other modes like those related to multipole surface-plasmon and bulk-plasmon emission. The present study shows the sensitivity of the calculated angular distributions to the scattering potentials and it also enlightens the important role play...

  5. Dwarf Ball: a 4π light-charged particle multidetector system for heavy-ion reaction mechanisms and spectroscopy

    International Nuclear Information System (INIS)

    The design and construction of a new spectrometer for heavy-ion reaction mechanism studies and for high spin spectroscopy is reported. The first version of this spectrometer consists of 72 fast-slow scintillator phoswiches packed with the same geometry as the spin spectrometer at the Holifield Heavy-Ion Research Facility and is small enough to fit inside the spin spectrometer. An improved version of the Dwarf Ball incorporates up to 85 detectors consisting primarily of CsI(T1) scintillators in a 4π arrangement and provides far superior performance in terms of energy resolution, particle identification, and dynamic range for energy measurements. The capabilities of the device for recording proton and α-particle spectra is discussed. The new possibilities for heavy-ion reaction studies and for nuclear spectroscopy that this device offers will be discussed

  6. Mechanisms of emission of particles charged in 6Li + 6Li and 6Li + 10B reactions at low energies

    International Nuclear Information System (INIS)

    The lithium 6 nucleus is a projectile of interest to study nuclear reactions at low energy due to the possibility to obtain high heats of reaction, and to its structure which can play an important role in the projectile-target interaction. This research thesis focused on the study of two low-energy reactions provoked by lithium projectiles. These reactions are studied within the framework of the theoretical model of aggregates. The first part presents the experimental conditions of both reactions, reports the development and analysis of nuclear plates, and the transformation of a given type of particle histogram into a spectrum in the mass centre system. The next parts report the study of the 6Li + 6Li reaction (previous results, kinematic analysis, spectrum of secondary particles, theoretical analysis of results) and of the 6Li + 10B reaction (previous results, experimental results, study of the continuous spectrum of alpha particle, reaction mechanisms)

  7. PTCDA chemisorbed on Ag(110): Dispersion interactions and charge equilibration

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, Reinhard [Walter Schottky Institut, TU Muenchen (Germany); Abbasi, Afshin [Institut fuer Physik, TU Chemnitz (Germany)

    2009-07-01

    The chemisorption of PTCDA on Ag(110) is analysed with 2{sup nd} order Moeller-Plesset perturbation theory (MP2), accounting therefore for the main part of the dispersion interactions at an ab initio level. Irrespective of the size of the rigid silver cluster used as a substrate model, the optimized geometry consists of a nearly flat perylene core, surrounded by carboxylic oxygens closer to the substrate, but with anhydride atoms at a larger height. The charge equilibration between adsorbate and substrate involves charge injection from the oxygen atoms into the substrate, and back transfer of two electrons into the former LUMO of the free molecule. Surprisingly, the resulting negative charge of the adsorbate has a very small contribution in the core region where the main part of the LUMO is localized, but instead accumulates on the end groups. It can be shown in detail that a rehybridization of molecular {sigma} and {pi} states results in a decoupling of several {pi} states on the oxygen atoms from the aromatic core, as opposed to the free molecule, where the {pi} states delocalize over the entire molecule. These decoupled {pi} states on the end groups are forming the binding Ag-O orbitals injecting electronic charge from the molecule into the substrate. Compared to the dominating mechanisms discussed above, the hybridization between orbitals in the core region and the underlying substrate plays only a minor role for the charge balance.

  8. Self-truncated ionization injection and consequent monoenergetic electron bunches in laser wakefield acceleration

    International Nuclear Information System (INIS)

    The ionization-induced injection in laser wakefield acceleration has been recently demonstrated to be a promising injection scheme. However, the energy spread controlling in this mechanism remains a challenge because continuous injection in a mixed gas target is usually inevitable. Here, we propose that by use of certain initially unmatched laser pulses, the electron injection can be constrained to the very front region of the mixed gas target, typically in a length of a few hundreds micrometers determined by the laser self-focusing and the wake deformation. As a result, the produced electron beam has narrow energy spread and meanwhile contains tens of pC in charge. Both multidimensional simulations and theoretical analysis illustrate the effectiveness of this scheme

  9. Polarization screening in polymer ferroelectric films: uncommon bulk mechanism

    OpenAIRE

    Mikheev, E.; Stolichnov, I.; Tagantsev, A. K.; Setter, N.

    2012-01-01

    Charge compensation at the interface is a fundamental phenomenon determining the operation conditions of thin-film devices incorporating ferroelectrics. The underlying mechanisms have been thoroughly addressed in perovskite ferroelectrics where the charge compensation originates from injection through the interface-adjacent layer. Here, we demonstrate that polarization screening in the polymer ferroelectric polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) films can be dominated by char...

  10. Effect of powder characteristics on the microstructures and mechanical properties of sintered alloy tool steel compacts by metal injection molding; Kinzoku funmatsu shashutsu seikeiho ni yoru shoketsu gokin koguko no soshiki oyobi kikaiteki seishitsu ni oyonodu funmatsu tokusei no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, H. [King invest Co. Ltd., Hiroshima (Japan); Kyogoku, H.; Komatsu, S. [Kinki University, Kyoto (Japan). Faculty of Engineering

    2000-12-15

    The effects of powder characteristics on the microstructures and mechanical properties of sintered alloy tool steel (SKD11) compacts by metal injection molding were investigated. A gas-atomized (GA) and a water-atomized (WA) alloy tool steel powders and a polyamide binder were used. They were mixed well and injected into metallic molds for transverse test specimens. These injection-molded specimens were debound at 593 K in air and then were sintered at various temperatures between 1,473 K and 1,483 K in vacuum. These sintered compacts were heated at 1,293 K and quenched, and then were tempered at various temperatures between 453 K and 803 K. The densification of the GA powder compact was fairly superior to that of the WA powder compacts. Consequently, the mechanical properties of the sintered GA powder compacts were superior to those of the sintered WA powder compacts. The mechanical properties equivalent to those of the wrought alloy tool steel could be fabricated successfully by controlling the sintering and heat-treatment conditions precisely. (author)

  11. Offset prediction for charge-balanced stimulus waveforms

    OpenAIRE

    Woods, V M; Triantis, I.; Toumazou, C.

    2011-01-01

    Functional electrical stimulation with cuff electrodes involves the controlled injection of current into an electrically excitable tissue for sensory or motor rehabilitation. Some charge injected during stimulation is 'lost' at the electrode-electrolyte interface when the charge carrier is translated from an electron to an ion in the solution. The process of charge injection through chemical reactions can reduce electrode longevity and implant biocompatibility. Conventionally, the excess char...

  12. 机电一体化在塑料模注射生产中的应用%Mechanical and Electrical Integration Application in the Plastic Injection Mold

    Institute of Scientific and Technical Information of China (English)

    桑玉红; 王明荣

    2011-01-01

    以带金属嵌件塑件注射模为例,设计进程中通过磁力作用解决了金属嵌件的定位问题,可以使用卧式注塑机注射成型,并利用气动元件完成两个模腔交替成型,实现注射过程的自动化,缩短塑件的注射成型周期,从而有效地节约了生产成本,提了高生产效率。%With a metal insert injection mold as an example, the design process through the action of magnetic force to solve the metal insert positioning, can use the horizontal injection molding machines injection molding, and the use of pneumatic components to complete a two mold cavity alternating molding, injection molding process automation, shorten the parts of the molding cycle, thereby effectively saving the cost of production put a high production efficiency.

  13. Fractional charges

    International Nuclear Information System (INIS)

    20 years ago fractional charges were imagined to explain values of conductivity in some materials. Recent experiments have proved the existence of charges whose value is the third of the electron charge. This article presents the experimental facts that have led theorists to predict the existence of fractional charges from the motion of quasi-particles in a linear chain of poly-acetylene to the quantum Hall effect. According to the latest theories, fractional charges are neither bosons nor fermions but anyons, they are submitted to an exclusive principle that is less stringent than that for fermions. (A.C.)

  14. A study on the shielding mechanisms of SOI pixel detector

    CERN Document Server

    Lu, Yunpeng; Wu, Zhigang; Ouyang, Qun; Arai, Yasuo

    2015-01-01

    In order to tackle the charge injection issue that had perplexed the counting type SOI pixel for years, two successive chips CPIXTEG3 and CPIXTEG3b were developed utilizing two shielding mechanisms, Nested-well and Double-SOI, in the LAPIS process. A TCAD simulation showed the shielding effectiveness influenced by the high sheet resistance of shielding layers. Test structures specially designed to measure the crosstalk associated to charge injection were implemented in CPIXTEG3/3b. Measurement results proved that using shielding layer is indispensable for counting type pixel and Double-SOI is superior to Nested-well in terms of shielding effectiveness and design flexibility.

  15. Embranquecimento do polipropileno isotático injetado contendo TiO2 como pigmento Whitening mechanism in injection molded polypropylene with TiO2 as pigment

    Directory of Open Access Journals (Sweden)

    Dênison R. J. Maia

    2000-12-01

    Full Text Available Descrevemos neste trabalho as causas e o mecanismo do embranquecimento de peças de polipropileno isotático injetado. Para isto foram injetados corpos de prova e placas com e sem estabilizantes. As amostras foram envelhecidas por exposição ambiental e em equipamento de envelhecimento acelerado (Weatherometer. Foi feito o acompanhamento visual das peças para que pudessem ser caracterizadas quando começassem a embranquecer. A caracterização foi feita através de espectroscopia FT-IR por reflectância, Microscopia eletrônica de varredura, Microfluorescência de raios-X, Reflectância de luz e Microanálise de energia dispersiva (EDS da superfície. Os espectros de infravermelho mostraram o aparecimento de diversos produtos de degradação como cetonas, aldeídos, ácidos carboxílicos, ésteres, perésteres e alfa-cetoésteres. Quando as amostras começaram a embranquecer foi verificada a formação de fissuras superficiais e o aumento da reflectância de luz para todos os comprimentos de onda do espectro. Concomitantemente foi verificado que a composição de superfície não é alterada pelo envelhecimento. A superfície não apresenta grande quantidade de partículas de TiO2 expostas. Conclui-se que o embranquecimento das peças é devido ao fissuramento superficial que aumenta a quantidade de luz refletida na superfície e não pela migração do pigmento.We studied in this work the whitening mechanism in injection molded polypropylene (PP, a problem usually manifested in car parts and particularly in car bumpers. For the development of this work we had samples (plaques and test samples with and without antioxidants and ultraviolet stabilizers. These samples had been already aged by natural and artificial (Weatherometer equipment exposure. In the natural aging samples were collected when the material started to whiten, after 3190, 4320 and 6190 h of exposure. In the artificial aging samples were collected after 415, 515 and 3000 h of

  16. 煤层注水致工作面前方集中应力前移的机理分析%Mechanism Analysis on Concentrated Stress in Front of Mining Face Moving Forward Occurred by Water Injection in Seam

    Institute of Scientific and Technical Information of China (English)

    李见波; 陈学习; 王新梅

    2012-01-01

    针对新兴矿煤层注水消除工作面冲击地压和煤与瓦斯突出过程中集中应力前移的问题,分析了注水润湿煤体并使其支撑能力下降而导致集中应力前移的机理;结合新兴矿地质条件,对钻孔注水过程进行了数值模拟,着重分析了注水后集中应力前移、煤壁位移增大和注水钻孔周边渗流场分布情况;数值模拟结果与理论分析结果相一致。另外推导出在注水时间一定时,注水钻孔的渗透半径及应力前移距离公式。%According to the concentrated stress moving forward problem occurred during the process of eliminating the mine pressure bumping and coal and gas outburst danger in the coal mining face with seam water injection in Xinxing Mine, the mechanism of water in- jection to wet coal body, reduced the seam support capacity, which would cause the stress moving forward was analyzed. In combination with the geological conditions of Xinxing Mine, a numerical simulation was conducted on the borehole water injection process. The concen- trated stress moving forward after the water injection, coal wall displacement increasing and the vadose field distribution condition around the water injection borehole were analyzed. The study results of the numerical simulation and the theoretical analysis results were same. A formula for the permeability radius of the water injection borehole and the stress moving forward distance was inferred when the water injec- tion time eonducted at the certain time.

  17. Injecting mould design with delay-pulling and multidirectional core-pulling mechanism%带有弯销延时抽芯的多方位抽芯注射模具设计

    Institute of Scientific and Technical Information of China (English)

    张晓岩; 杜继涛; 杨梅

    2012-01-01

    给出一种带有弯销延时抽芯的多方位抽芯方法,阐述其工作原理及具体模具结构,并对模具的潜伏式浇口、弯销延时抽芯机构、内抽结构以及推块顶出等关键技术进行分析.整个模具结构紧凑,动作可靠,成型出的塑件表面质量较高,满足生产要求.%The design of a multidirectional core delay-pulling mechanism in injection mould was presented. The working principle of the mechanism and the structure of the injection mould were described. The key technologies were analyzed such as submarine gate, bending pin postponing core-pulling mechanism, lifters, ejector plate pulling mechanism. It is distinct in compact structure and reliable operation. The plastic parts have an excellent surface quality and are satisfied with requirements of production.

  18. Charged Condensation

    CERN Document Server

    Gabadadze, Gregory

    2008-01-01

    We consider Bose-Einstein condensation of massive electrically charged scalars in a uniform background of charged fermions. We focus on the case when the scalar condensate screens the background charge, while the net charge of the system resides on its boundary surface. A distinctive signature of this substance is that the photon acquires a Lorentz-violating mass in the bulk of the condensate. Due to this mass, the transverse and longitudinal gauge modes propagate with different group velocities. We give qualitative arguments that at high enough densities and low temperatures a charged system of electrons and helium-4 nuclei, if held together by laboratory devices or by force of gravity, can form such a substance. We briefly discuss possible manifestations of the charged condensate in compact astrophysical objects.

  19. Highly Charged Ion Sources

    International Nuclear Information System (INIS)

    In this work a study is made for the factors affecting the production and extraction of highly charged ion beams. Discussion is made for the production of highly charged ions from: the conventional vacuum are ion sources (Pinning PIG and Duoplasmatron DP) and the recent trends type which are (Electron Beam Ion Sources EBIS, Electron Cyclotron Resonance Ion Sources ECRIS and Laser Ion source LIS). The highly charged ions with charge state +7 , O+8 ,Ne+10 , Ar+18 have been extracted from the ECRIS while fully stripped Xe+54 has been extracted from EBIS. Improving the capabilities of the conventional RF ion source to produce multiply charged ions is achieved through the use of electron injection into the plasma or with the use of RF driven ion source. The later is based on coupling the RF power to the discharge through an internal antenna in vacuum are ion source. The argon ion species extracted from these upgraded RF ion sources could reach Ar+5

  20. CFD Investigation into Diesel PCCI Combustion with Optimized Fuel Injection

    OpenAIRE

    Lipeng Lu; Bin Liu; Weiji Wang; Zhijun Peng

    2011-01-01

    A multi-pulse injection strategy for premixed charge compression ignition (PCCI) combustion was investigated in a four-valve, direct-injection diesel engine by a computational fluid dynamics (CFD) simulation using KIVA-3V code coupled with detailed chemistry. The effects of fuel splitting proportion, injection timing, spray angles, and injection velocity were examined. The mixing process and formation of soot and nitrogen oxide (NO x ) emissions were investigated as the focus of the research....