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Sample records for capacitance deep level

  1. Capacitance transient study of a bistable deep level in e--irradiated n-type 4H-SiC

    Beyer, F C; Hemmingsson, C G; Pedersen, H; Henry, A; Janzén, E; Isoya, J; Ohshima, T; Morishita, N

    2012-01-01

    Using capacitance transient techniques, a bistable centre, called FB centre here, was observed in electron irradiated 4H-SiC. In configuration A, the deep level known as EH5 (E a = E C - 1.07 eV) is detected in the deep level transient spectroscopy spectrum, whereas for configuration B no obvious deep level is observed in the accessible part of the band gap. Isochronal annealing revealed the transition temperatures to be T A→B > 730 K and for the opposite process T B→A ≈ 710 K. The energy needed to conduct the transformations were determined to be E A (A → B) = (2.1 ± 0.1) eV and E A (B → A) = (2.3 ± 0.1) eV, respectively. The pre-factor indicated an atomic jump process for the opposite transition A → B and a charge carrier-emission dominated process in the case of B → A. Minority charge carrier injection enhanced the transformation from configuration B to configuration A by lowering the transition barrier by about 1.4 eV. Since the bistable FB centre is already present after low-energy electron irradiation (200 keV), it is likely related to carbon.

  2. A transient simulation approach to obtaining capacitance-voltage characteristics of GaN MOS capacitors with deep-level traps

    Fukuda, Koichi; Asai, Hidehiro; Hattori, Junichi; Shimizu, Mitsuaki; Hashizume, Tamotsu

    2018-04-01

    In this study, GaN MOS capacitance-voltage device simulations considering various interface and bulk traps are performed in the transient mode. The simulations explain various features of capacitance-voltage curves, such as plateau, hysteresis, and frequency dispersions, which are commonly observed in measurements of GaN MOS capacitors and arise from complicated combinations of interface and bulk deep-level traps. The objective of the present study is to provide a good theoretical tool to understand the physics of various nonideal measured curves.

  3. Capacitance level probe, Type FSK 88

    Vogt, W.

    2001-01-01

    The aim of the capacitive level probe, Type FSK 88, is to supervise the level within vessels continuously and to signalize alterations immediately. Since 1987 the level probe is installed in the pool for burn up fuel elements and in the reactor containment sump of BWRs, PWRs and WWERs. The capacitive level probe of type FSK 88 was qualified for Loss of Coolant Accidents and seismic events according to international rules. The measuring principle takes credit from the fact that the dielectric with different dielectric constants in a condensator changes the capacity of the condensator. (Authors)

  4. Automated capacitive spectrometer for measuring the parameters of deep centers in semiconductor materials

    Shajmeev, S.S.

    1985-01-01

    An automated capacitive spectrometer for determining deep centers parameters in semiconductor materials and instruments is described. The facility can be used in studying electrically active defects (impurity, radiation, thermal) having deep levels in the forbidden semiconductor zone. The facility permits to determine the following parameters of the deep centers: concentration of each deep level taken separately within 5x10 -1 +-5x10 -15 of the alloying impurity concentration, level energy position in the forbidden semiconductor zone in the range from 0.08 MeV above the valency zone ceiling to 0.08 eV below the conductivity zone bottom, hole or electron capture cross-section on the deep center; concentration profile of deep levels

  5. A new interface weak-capacitance detection ASIC of capacitive liquid level sensor in the rocket

    Yin, Liang; Qin, Yao; Liu, Xiao-Wei

    2017-11-01

    A new capacitive liquid level sensing interface weak-capacitance detection ASIC has been designed. This ASIC realized the detection of the output capacitance of the capacitive liquid level sensor, which converts the output capacitance of the capacitive liquid level sensor to voltage. The chip is fabricated in a standard 0.5μm CMOS process. The test results show that the linearity of capacitance detection of the ASIC is 0.05%, output noise is 3.7aF/Hz (when the capacitance which will be detected is 40 pF), the stability of capacitance detection is 7.4 × 10-5pF (1σ, 1h), the output zero position temperature coefficient is 4.5 uV/∘C. The test results prove that this interface ASIC can meet the requirement of high accuracy capacitance detection. Therefore, this interface ASIC can be applied in capacitive liquid level sensing and capacitive humidity sensing field.

  6. Interpretation of transconductance dispersion in AlGaAs/InGaAs pseudomorphic high electron mobility transistor by capacitance deep level transient spectroscopy

    Choi, K J; Yoo, H M; Lee, G Y

    1998-01-01

    The transconductance dispersion in AlGaAs/InGaAs PHEMT grown by MBE was interpreted by means of capacitance DLTS technique. When the gate bias was -0.2 V, the transconductance decreased at a very broad frequency range of 5.5 Hz -1.7x10 sup 4 Hz. However, when a positive bias was applied to the gate, the transconductance increased at a low frequency range and then decreased at a high frequency range. In the transconductance dispersion measurement as a function of temperature, the transition frequency shifted to higher frequency region with the increase in temperature. The emission energy for the change in the transition frequency was determined to be 0.394 eV from the temperature dependency of the transition frequency. In the capacitance DLTS measurements, we observed DX-center with thermal activation energy of 0.420 eV and two hole trap-like signals. The DX-center peak decreased as the filling pulse decreased from +0.6 V and disappeared at the bias of -0.1 V. Comparing the activation energy of DX-center in DL...

  7. New Type Multielectrode Capacitance Sensor for Liquid Level

    Zhao, Y R [China University of Petroleum (Huadong), Qingdao (China); Shi, A P [Shandong University of Science and Technology, Qingdao (China); Chen, G Q [Shandong University of Science and Technology, Qingdao (China); Chang, Y Y [Shandong University of Science and Technology, Qingdao (China); Hang, Z [Shandong University of Science and Technology, Qingdao (China); Liu, B M [Binzhou University, Binzhou (China)

    2006-10-15

    This paper introduces the design of a new type multielectrode capacitance sensor for liquid level. The system regards electric field sensor MC33794 as the core and applies microcontroller MC9S12DJ128 to realize intelligent liquid level monitoring system, which overcomes the disadvantages of the traditional capacitance sensor, improves on the anti-jamming ability and the measurement precision and simplifies the system structure. Finally, the paper sums up the design of the system.

  8. Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

    Kaganovich, Igor D.

    2002-01-01

    A novel nonlinear effect of anomalously deep penetration of an external radio-frequency electric field into a plasma is described. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order V(subscript T)/omega, where V(subscript T) is the electron thermal velocity, and w is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected

  9. Sensitivity Enhancement of a PPM Level Capacitive Moisture Sensor

    Lokesh Kumar

    2017-05-01

    Full Text Available Measurement of moisture at ppm or ppb level is very difficult and the fabrication of such sensors at low cost is always challenging. High sensitivity is an important parameter for trace level (ppm humidity sensors. Anelectronic detection circuit for interfacing the humidity sensor with high sensitivity requires a simple hardware circuit with few active devices. The recent trends for increasing the sensitivity include fabricating nanoporous film with a very large surface area. In the present work, the sensitivity of a parallel plate capacitive type sensor with metal oxide sensing film has been significantly improved with an aim to detect moisture from 3 to 100 ppm in the industrial process gases used to fabricate semiconductors and other sensitive electronic devices. The sensitivity has been increased by (i fabricating a nanoporous film of aluminum oxide using the sol-gel method and (ii increasing the cross-sectional area of a parallel plate capacitor. A novel double sided capacitive structure has been proposed where two capacitors have been fabricated—one on the top and one on the bottom side of a flat alumina substrate—and then the capacitors are connected in parallel. The structure has twice the sensitivity of a single sensor in the same ppm range but the size of the structure remains unchanged. The important characteristics of the sensors such as the sensitivity (S = Δ C Δ p p m × 100 , the response time (tr, and the recovery time (tc are determined and compared with a commercial SHAW, UKdew point meter. The fabricated double sided sensor has comparable sensitivity (S = 100%, tr (s = 28, tc (s = 40 with the commercial meter (S = 100.5%, tr (s = 258 but has a faster response time. The proposed method of sensitivity enhancement is simple, and mass producible.

  10. Deep-depletion physics-based analytical model for scanning capacitance microscopy carrier profile extraction

    Wong, K. M.; Chim, W. K.

    2007-01-01

    An approach for fast and accurate carrier profiling using deep-depletion analytical modeling of scanning capacitance microscopy (SCM) measurements is shown for an ultrashallow p-n junction with a junction depth of less than 30 nm and a profile steepness of about 3 nm per decade change in carrier concentration. In addition, the analytical model is also used to extract the SCM dopant profiles of three other p-n junction samples with different junction depths and profile steepnesses. The deep-depletion effect arises from rapid changes in the bias applied between the sample and probe tip during SCM measurements. The extracted carrier profile from the model agrees reasonably well with the more accurate carrier profile from inverse modeling and the dopant profile from secondary ion mass spectroscopy measurements

  11. A capacitive level shifter for high voltage (2.5kV)

    Andersen, Thomas; Andersen, Michael A. E.; Thomsen, Ole Cornelius

    2012-01-01

    with focus on low power consumption as well as low capacitive load between the floating half-bridge node and ground (output capacitance). The operation of the level-shifter is tested and verified by measurements on a prototype half-bridge gate driver. Results conclude stabile operation at 2.44kV, 50k...

  12. Studies of deep levels in He+-irradiated silicon

    Schmidt, D.C.; Barbot, J.F.; Blanchard, C.

    1997-01-01

    Deep levels created in n-epitaxial silicon by alpha particle irradiation in the dose range from 10 9 to 10 13 particles/cm 2 have been investigated by the deep level transient spectroscopy technique and capacitance-voltage profiling. Under low fluence irradiation at least four main electron traps have been observed. With further increase in irradiation fluence, two new levels located at E c -0.56 eV and E c -0.64 eV appear on the high-temperature side of the DLTS signal. The slope change observed in the amplitude variations of the singly negative charge state of the divacancy versus the dose takes place when these two new levels appear. This suggests that both are multivacancy-related defects. After annealing at 350 C for 15 min, all electron traps have disappeared. Moreover, no shallow levels are created during the annealing. (orig.)

  13. Design, Development and Testing of a Semi Cylindrical Capacitive Sensor for Liquid Level Measurement

    Sagarika PAL

    2010-05-01

    Full Text Available In the present paper a low cost noncontact semi cylindrical capacitive type liquid level sensor has been designed, developed and tested. The semi cylindrical capacitive sensor consisting of two thin semi cylindrical metal plates separated by a gap distance and mounted around a non conducting storage tank, has been used to measure the liquid level in the tank. The measured capacitance variation with variation of liquid level is linear and obtained in the nano farad range which again has been converted into voltage variation by using proper signal conditioning circuit. Since the sensor is noncontact type it can be used for both conducting and non conducting type of liquid contained within a non conducting tank. For converting the capacitance variation in to voltage variation a series R-L-C resonating circuit has been used instead of conventional bridge circuit. Experimental results confirm the satisfactory performance of the sensor for liquid level measurement.

  14. Levels of semenogelin in human spermatozoa decrease during capacitation: involvement of reactive oxygen species and zinc.

    de Lamirande, E; Lamothe, G

    2010-07-01

    Semenogelin (Sg), the main protein of human semen coagulum, prevents sperm capacitation. The objective of this study was to examine the role of Sg and its mechanism of action. Sg blocked sperm capacitation triggered by various stimuli, via inhibition of superoxide anion (O(2)*-; luminescence assay) and nitric oxide (NO*; tested using diaminofluorescein) generation. Triton-soluble and -insoluble sperm fractions contained Sg and Sg peptides (immunoblotting), the level of which decreased with initiation of capacitation. This drop was prevented by superoxide dismutase and NO* synthase inhibitor and was reproduced by addition of O(2)*- and NO*. Zinc (Zn(2+)) blocked and a zinc chelator (TPEN) promoted the decline in Sg levels. There was a decreased labelling of Sg on the head in capacitating spermatozoa with the two fixation techniques tested (immunocytochemistry). Reactive oxygen species (ROS) (O(2)*- and NO*) caused, these changes, and zinc prevented them. Spermatozoa quickly internalized Sg upon incubation and Sg was then rapidly degraded in a zinc-inhibitable manner. Sg blocked capacitation mainly via inhibition of ROS generation. Spermatozoa appeared permeable to Sg and processed Sg in a zinc-inhibitable fashion. ROS themselves could promote sperm disposal of Sg which maybe one of the mechanisms that allows initiation of capacitation.

  15. Development of capacitive sensor for automatically measuring tumbler water level with FEA simulation.

    Wei, Qun; Kim, Mi-Jung; Lee, Jong-Ha

    2018-01-01

    Drinking water has several advantages that have already been established, such as improving blood circulation, reducing acid in the stomach, etc. However, due to people not noticing the amount of water they consume every time they drink, most people drink less water than the recommended daily allowance. In this paper, a capacitive sensor for developing an automatic tumbler to measure water level is proposed. Different than in previous studies, the proposed capacitive sensor was separated into two sets: the main sensor for measuring the water level in the tumbler, and the reference sensor for measuring the incremental level unit. In order to confirm the feasibility of the proposed idea, and to optimize the shape of the sensor, a 3D model of the capacitive sensor with the tumbler was designed and subjected to Finite Element Analysis (FEA) simulation. According to the simulation results, the electrodes were made of copper and assembled in a tumbler manufactured by a 3D printer. The tumbler was filled with water and was subjected to experiments in order to assess the sensor's performance. The comparison of experimental results to the simulation results shows that the measured capacitance value of the capacitive sensor changed linearly as the water level varied. This proves that the proposed sensor can accurately measure the water level in the tumbler. Additionally, by use of the curve fitting method, a compensation algorithm was found to match the actual level with the measured level. The experimental results proved that the proposed capacitive sensor is able to measure the actual water level in the tumbler accurately. A digital control part with micro-processor will be designed and fixed on the bottom of the tumbler for developing a smart tumbler.

  16. Admittance spectroscopy or deep level transient spectroscopy: A contrasting juxtaposition

    Bollmann, Joachim; Venter, Andre

    2018-04-01

    A comprehensive understanding of defects in semiconductors remains of primary importance. In this paper the effectiveness of two of the most commonly used semiconductor defect spectroscopy techniques, viz. deep level transient spectroscopy (DLTS) and admittance spectroscopy (AS) are reviewed. The analysis of defects present in commercially available SiC diodes shows that admittance spectroscopy allows the identification of deep traps with reduced measurement effort compared to deep Level Transient Spectroscopy (DLTS). Besides the N-donor, well-studied intrinsic defects were detected in these diodes. Determination of their activation energy and defect density, using the two techniques, confirm that the sensitivity of AS is comparable to that of DLTS while, due to its well defined peak shape, the spectroscopic resolution is superior. Additionally, admittance spectroscopy can analyze faster emission processes which make the study of shallow defects more practical and even that of shallow dopant levels, possible. A comparative summary for the relevant spectroscopic features of the two capacitance methods are presented.

  17. Characterization of majority and minority carrier deep levels in p-type GaN:Mg grown by molecular beam epitaxy using deep level optical spectroscopy

    Armstrong, A.; Caudill, J.; Ringel, S. A.; Corrion, A.; Poblenz, C.; Mishra, U. K.; Speck, J. S.

    2008-01-01

    Deep level defects in p-type GaN:Mg grown by molecular beam epitaxy were characterized using steady-state photocapacitance and deep level optical spectroscopy (DLOS). Low frequency capacitance measurements were used to alleviate dispersion effects stemming from the deep Mg acceptor. Use of DLOS enabled a quantitative survey of both deep acceptor and deep donor levels, the latter being particularly important due to the limited understanding of minority carrier states for p-type GaN. Simultaneous electron and hole photoemissions resulted in a convoluted deep level spectrum that was decoupled by emphasizing either majority or minority carrier optical emission through control of the thermal filling time conditions. In this manner, DLOS was able to resolve and quantify the properties of deep levels residing near both the conduction and valence bandedges in the same sample. Bandgap states through hole photoemission were observed at E v +3.05 eV, E v +3.22 eV and E v +3.26 eV. Additionally, DLOS revealed levels at E c -3.24 eV and E c -2.97 eV through electron emission to the conduction band with the former attributed to the Mg acceptor itself. The detected deep donor concentration is less than 2% of activated [Mg] and demonstrates the excellent quality of the film

  18. Deep Ocean Contribution to Sea Level Rise

    Chang, L.; Sun, W.; Tang, H.; Wang, Q.

    2017-12-01

    The ocean temperature and salinity change in the upper 2000m can be detected by Argo floats, so we can know the steric height change of the ocean. But the ocean layers above 2000m represent only 50% of the total ocean volume. Although the temperature and salinity change are small compared to the upper ocean, the deep ocean contribution to sea level might be significant because of its large volume. There has been some research on the deep ocean rely on the very sparse situ observation and are limited to decadal and longer-term rates of change. The available observational data in the deep ocean are too spares to determine the temporal variability, and the long-term changes may have a bias. We will use the Argo date and combine the situ data and topographic data to estimate the temperature and salinity of the sea water below 2000m, so we can obtain a monthly data. We will analyze the seasonal and annual change of the steric height change due to the deep ocean between 2005 and 2016. And we will evaluate the result combination the present-day satellite and in situ observing systems. The deep ocean contribution can be inferred indirectly as the difference between the altimetry minus GRACE and Argo-based steric sea level.

  19. Seawater capacitance – a promising proxy for mapping and characterizing drifting hydrocarbon plumes in the deep ocean

    J. A. Fleming

    2012-12-01

    Full Text Available Hydrocarbons released into the deep ocean are an inevitable consequence of natural seep, seafloor drilling, and leaking wellhead-to-collection-point pipelines. The Macondo 252 (Deepwater Horizon well blowout of 2010 was even larger than the Ixtoc event in the Gulf of Campeche in 1979. History suggests it will not be the last accidental release, as deepwater drilling expands to meet an ever-growing demand. For those who must respond to this kind of disaster, the first line of action should be to know what is going on. This includes knowing where an oil plume is at any given time, where and how fast it is moving, and how it is evolving or degrading. We have experimented in the laboratory with induced polarization as a method to track hydrocarbons in the seawater column and find that finely dispersed oil in seawater gives rise to a large distributed capacitance. From previous sea trials, we infer this could potentially be used to both map and characterize oil plumes, down to a ratio of less than 0.001 oil-to-seawater, drifting and evolving in the deep ocean. A side benefit demonstrated in some earlier sea trials is that this same approach in modified form can also map certain heavy placer minerals, as well as communication cables, pipelines, and wrecks buried beneath the seafloor.

  20. Variations in creatine kinase activity and reactive oxygen species levels are involved in capacitation of bovine spermatozoa.

    Córdoba, M; Pintos, L; Beconi, M T

    2008-12-01

    The generation of reactive oxygen species (ROS) is associated with some factors such as oxidative substrate sources, mitochondrial function and NAD(P)H oxidase activity. In bovine spermatozoa, heparin capacitation produces a respiratory burst sensitive to diphenyleneiodonium (DPI). Creatine kinase (CK) is related to extramitochondrial ATP disponibility. Our purpose was to determine the variation in ROS level and its relation with NAD(P)H oxidase sensitive to DPI and CK participation, as factors involved in redox state and energy generation in capacitation. The chlortetracycline technique was used to evaluate capacitation. CK activity and ROS level were measured by spectrophotometry and spectrofluorometry respectively. The capacitation percentage was increased by heparin or quercetin treatment (P level as control (238.62 +/- 23.47 arbitrary units per 10(8) spermatozoa) (P > 0.05). CK activity decreased by 50% with heparin or quercetin (P level variations were observed in heparin- or quercetin-treated samples (P bovine spermatozoa, capacitation requires equilibrium between oxidative damage susceptibility and ROS levels. CK activity is associated with redox state variation and energy sources. In conclusion, capacitation induction depends on NADPH oxidase and the shuttle creatine-creatine phosphate, both sensitive to DPI.

  1. Deep Inelastic Scattering at the Amplitude Level

    Brodsky, Stanley J.

    2005-01-01

    The deep inelastic lepton scattering and deeply virtual Compton scattering cross sections can be interpreted in terms of the fundamental wavefunctions defined by the light-front Fock expansion, thus allowing tests of QCD at the amplitude level. The AdS/CFT correspondence between gauge theory and string theory provides remarkable new insights into QCD, including a model for hadronic wavefunctions which display conformal scaling at short distances and color confinement at large distances

  2. Deep levels in silicon–oxygen superlattices

    Simoen, E; Jayachandran, S; Delabie, A; Caymax, M; Heyns, M

    2016-01-01

    This work reports on the deep levels observed in Pt/Al 2 O 3 /p-type Si metal-oxide-semiconductor capacitors containing a silicon–oxygen superlattice (SL) by deep-level transient spectroscopy. It is shown that the presence of the SL gives rise to a broad band of hole traps occurring around the silicon mid gap, which is absent in reference samples with a silicon epitaxial layer. In addition, the density of states of the deep layers roughly scales with the number of SL periods for the as-deposited samples. Annealing in a forming gas atmosphere reduces the maximum concentration significantly, while the peak energy position shifts from close-to mid-gap towards the valence band edge. Based on the flat-band voltage shift of the Capacitance–Voltage characteristics it is inferred that positive charge is introduced by the oxygen atomic layers in the SL, indicating the donor nature of the underlying hole traps. In some cases, a minor peak associated with P b dangling bond centers at the Si/SiO 2 interface has been observed as well. (paper)

  3. A Neural Network Approach to Fluid Level Measurement in Dynamic Environments Using a Single Capacitive Sensor

    Edin TERZIC

    2010-03-01

    Full Text Available A measurement system has been developed using a single tube capacitive sensor to accurately determine the fluid level in vehicular fuel tanks. A novel approach based on artificial neural networks based signal pre-processing and classification has been described in this article. A broad investigation on the Backpropagation neural network and some selected signal pre-processing filters, namely, Moving Mean, Moving Median, and Wavelet Filter has also been presented. An on field drive trial was conducted under normal driving conditions at various fuel volumes ranging from 5 L to 50 L to acquire training samples from the capacitive sensor. A second field trial was conducted to obtain test samples to verify the performance of the neural network. The neural network was trained and verified with 50 % of the training and test samples. The results obtained using the neural network approach having different filtration methods are compared with the results obtained using simple Moving Mean and Moving Median functions. It is demonstrated that the Backpropagation neural network with Moving Median filter produced the most accurate outcome compared with the other signal filtration methods.

  4. Studies on deep electronic levels in silicon and aluminium gallium arsenide alloys

    Pettersson, H.

    1993-01-01

    This thesis reports on investigations of the electrical and optical properties of deep impurity centers, related to the transition metals (TMs) Ti, Mo, W, V and Ni, in silicon. Emission rates, capture cross sections and photoionization cross sections for these impurities were determined by means of various Junction Space Charge Techniques (JSCTs), such as Deep Level Transient Spectroscopy (DLTS), dark capacitance transient and photo capacitance transient techniques. Changes in Gibbs free energy as a function of temperature were calculated for all levels. From this temperature dependence, the changes in enthalpy and entropy involved in the electron and hole transitions were deduced. The influence of high electric fields on the electronic levels in chalcogen-doped silicon were investigated using the dark capacitance transient technique. The enhancement of the electron emission from the deep centers indicated a more complex field enhancement model than the expected Poole-Frenkel effect for coulombic potentials. The possibility to determine charge states of defects using the Poole-Frenkel effect, as often suggested, is therefore questioned. The observation of a persistent decrease of the dark conductivity due to illumination in simplified AlGaAs/GaAs high Electron Mobility Transistors (HEMTs) over the temperature range 170K< T<300K is reported. A model for this peculiar behavior, based on the recombination of electrons in the two-dimensional electron gas (2DEG) located at the AlGaAs/GaAs interface with holes generated by a two-step excitation process via the deep EL2 center in the GaAs epilayer, is put forward

  5. Bevacizumab-Based Chemotherapy Combined with Regional Deep Capacitive Hyperthermia in Metastatic Cancer Patients: A Pilot Study.

    Ranieri, Girolamo; Ferrari, Cristina; Di Palo, Alessandra; Marech, Ilaria; Porcelli, Mariangela; Falagario, Gianmarco; Ritrovato, Fabiana; Ramunni, Luigi; Fanelli, Margherita; Rubini, Giuseppe; Gadaleta, Cosmo Damiano

    2017-07-06

    As an angiogenesis inhibitor, bevacizumab has been investigated in combination with different chemotherapeutic agents, achieving an established role for metastatic cancer treatment. However, potential synergic anti-angiogenic effects of hyperthermia have not tested to date in literature. The aim of our study was to analyze efficacy, safety, and survival of anti-angiogenic-based chemotherapy associated to regional deep capacitive hyperthermia (HT) in metastatic cancer patients. Twenty-three patients with metastatic colorectal ( n = 16), ovarian ( n = 5), and breast ( n = 2) cancer were treated with HT in addition to a standard bevacizumab-based chemotherapy regimen. Treatment response assessment was performed, according to the modified Response Evaluation Criteria for Solid Tumors (mRECIST), at 80 days (timepoint-1) and at 160 days (timepoint-2) after therapy. Disease Response Rate (DRR), considered as the proportion of patients who had the best response rating (complete response (CR), partial response (PR), or stable disease (SD)), was assessed at timepoint-1 and timepoint-2. Chi-squared for linear trend test was performed to evaluated the association between response groups (R/NR) and the number of previous treatment (none, 1, 2, 3), number of chemotherapy cycles (12), number of hyperthermia sessions (24), and lines of chemotherapy (I, II). Survival curves were estimated by Kaplan-Meier method. DRR was 85.7% and 72.2% at timepoint-1 and timepoint-2, respectively. HT was well tolerated without additional adverse effects on chemotherapy-related toxicity. Chi-squared for linear trend test demonstrated that the percentage of responders grew in relation to the number of chemotherapy cycles ( p = 0.015) and to number of HT sessions ( p chemotherapy cycles ( p chemotherapy with HT has a favorable tumor response, is feasible and well tolerated, and offers a potentially promising option for metastatic cancer patients.

  6. Impact of proton irradiation on deep level states in n-GaN

    Zhang, Z.; Arehart, A. R.; Cinkilic, E.; Ringel, S. A.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; McSkimming, B.; Speck, J. S.

    2013-01-01

    Deep levels in 1.8 MeV proton irradiated n-type GaN were systematically characterized using deep level transient spectroscopies and deep level optical spectroscopies. The impacts of proton irradiation on the introduction and evolution of those deep states were revealed as a function of proton fluences up to 1.1 × 10 13 cm −2 . The proton irradiation introduced two traps with activation energies of E C - 0.13 eV and 0.16 eV, and a monotonic increase in the concentration for most of the pre-existing traps, though the increase rates were different for each trap, suggesting different physical sources and/or configurations for these states. Through lighted capacitance voltage measurements, the deep levels at E C - 1.25 eV, 2.50 eV, and 3.25 eV were identified as being the source of systematic carrier removal in proton-damaged n-GaN as a function of proton fluence

  7. Assessment of an ultrasonic sensor and a capacitance probe for measurement of two-phase mixture level

    Kim, Chang Hyun; Lee, Dong Won; No, Hee Cheon

    2004-01-01

    We performed a comparison of two-phase mixture levels measured by an ultrasonic sensor and a two-wire type capacitance probe with visual data under the same experimental conditions. A series of experiments are performed with various combinations of airflow and initial water level using a test vessel with a height of 2m and an inner diameter of 0.3m. The ultrasonic sensor measured the two-phase mixture level with a maximum error of 1.77% with respect to the visual data. The capacitance probe severely under-predicted the level data in the high void fraction region. The cause of the error was identified as the change of the dielectric constant as the void fraction changes when the probe is applied to the measurement of the two-phase mixture levels. A correction method for the capacitance probe is proposed by correcting the change of the dielectric constant of the two-phase mixture. The correction method for the capacitance probe produces a r.m.s. error of 5.4%. The present experimental data are compared with the existing pool void fraction correlations based on drift-flux model. The Kataoka-Ishii correlation has the best agreement with the present experimental data with an r.m.s error of 2.5%

  8. Assessment of an ultrasonic sensor and a capacitance probe for measurement of two-phase mixture level

    Kim, Chang Hyun; Lee, Dong Won; No, Hee Cheon

    2004-01-01

    We perform a comparison of two-phase mixture levels measured by an ultrasonic sensor and a two-wire type capacitance probe with visual data under the same experimental conditions. A series of experiments are performed with various combinations of airflow and initial water level using a test vessel with a height of 2m and an inner diameter of 0.3 m under atmospheric pressure and room temperature. The ultrasonic sensor measures the two-phase mixture level with a maximum error of 1.77% with respect to the visual data. The capacitance probe severely under-predicts the level data in the high void fraction region. The cause of the error is identified as the change of the dielectric constant as the void fraction changes when the probe is applied to the measurement of the two-phase mixture levels. A correction method for the capacitance probe is proposed by correcting the change of dielectric constant of the two-phase mixture. The correction method for the capacitance probe produces a r.m.s. error of 5.4%. (author)

  9. Positron deep level transient spectroscopy — a new application of positron annihilation to semiconductor physics

    Beling, C. D.; Fung, S.; Au, H. L.; Ling, C. C.; Reddy, C. V.; Deng, A. H.; Panda, B. K.

    1997-05-01

    Recent positron mobility and lifetime measurements made on ac-biased metal on semi-insulating GaAs junctions, which have identified the native EL2 defect through a determination of the characteristic ionization energy of the donor level, are reviewed. It is shown that these measurements point towards a new spectroscopy, tentatively named positron-DLTS (deep level transient spectroscopy), that is the direct complement to conventional DLTS in that it monitors transients in the electric field of the depletion region rather than the inversely related depletion width, as deep levels undergo ionization. In this new spectroscopy, which may be applied to doped material by use of a suitable positron beam, electric field transients are monitored through the Doppler shift of the annihilation radiation resulting from the drift velocity of the positron in the depletion region. Two useful extensions of the new spectroscopy beyond conventional capacitance-DLTS are suggested. The first is that in some instances information on the microstructure of the defect causing the deep level may be inferred from the sensitivity of the positron to vacancy defects of negative and neutral charge states. The second is that the positron annihilation technique is intrinsically much faster than conventional DLTS with the capability of observing transients some 10 6 times faster, thus allowing deep levels (and even shallow levels) to be investigated without problems associated with carrier freeze-out.

  10. Online monitoring of oil film using electrical capacitance tomography and level set method

    Xue, Q.; Ma, M.; Sun, B. Y.; Cui, Z. Q.; Wang, H. X.

    2015-01-01

    In the application of oil-air lubrication system, electrical capacitance tomography (ECT) provides a promising way for monitoring oil film in the pipelines by reconstructing cross sectional oil distributions in real time. While in the case of small diameter pipe and thin oil film, the thickness of the oil film is hard to be observed visually since the interface of oil and air is not obvious in the reconstructed images. And the existence of artifacts in the reconstructions has seriously influenced the effectiveness of image segmentation techniques such as level set method. Besides, level set method is also unavailable for online monitoring due to its low computation speed. To address these problems, a modified level set method is developed: a distance regularized level set evolution formulation is extended to image two-phase flow online using an ECT system, a narrowband image filter is defined to eliminate the influence of artifacts, and considering the continuity of the oil distribution variation, the detected oil-air interface of a former image can be used as the initial contour for the detection of the subsequent frame; thus, the propagation from the initial contour to the boundary can be greatly accelerated, making it possible for real time tracking. To testify the feasibility of the proposed method, an oil-air lubrication facility with 4 mm inner diameter pipe is measured in normal operation using an 8-electrode ECT system. Both simulation and experiment results indicate that the modified level set method is capable of visualizing the oil-air interface accurately online

  11. Constant-resistance deep-level transient spectroscopy in Si and Ge JFET's

    Kolev, P.V.; Deen, J.

    1999-01-01

    The recently introduced constant-resistance deep-level transient spectroscopy (CR-DLTS) was successfully applied to study virgin and radiation-damaged junction field-effect transistors (JFET's). The authors have studied three groups of devices: commercially available-discrete silicon JFET's; virgin and exposed to high-level neutron radiation silicon JFET's, custom-made by using a monolithic technology; and commercially available discrete germanium p-channel JFET's. CR-DLTS is similar to both the conductance DLTs and to the constant-capacitance variation (CC-DLTS). Unlike the conductance and current DLTS, it is independent of the transistor size and does not require simultaneous measurement of the transconductance or the free-carrier mobility for calculation of the trap concentration. Compared to the CC-DLTS, it measures only the traps inside the gate-controlled part of the space charge region. Comparisons have also been made with the CC-DLTS and standard capacitance DLTS. In addition, possibilities for defect profiling in the channel have been demonstrated. CR-DLTS was found to be a simple, very sensitive, and device area-independent technique which is well suited for measurement of a wide range of deep level concentrations in transistors

  12. A hybrid algorithm for stochastic single-source capacitated facility location problem with service level requirements

    Hosseinali Salemi

    2016-04-01

    Full Text Available Facility location models are observed in many diverse areas such as communication networks, transportation, and distribution systems planning. They play significant role in supply chain and operations management and are one of the main well-known topics in strategic agenda of contemporary manufacturing and service companies accompanied by long-lasting effects. We define a new approach for solving stochastic single source capacitated facility location problem (SSSCFLP. Customers with stochastic demand are assigned to set of capacitated facilities that are selected to serve them. It is demonstrated that problem can be transformed to deterministic Single Source Capacitated Facility Location Problem (SSCFLP for Poisson demand distribution. A hybrid algorithm which combines Lagrangian heuristic with adjusted mixture of Ant colony and Genetic optimization is proposed to find lower and upper bounds for this problem. Computational results of various instances with distinct properties indicate that proposed solving approach is efficient.

  13. Scanning ion deep level transient spectroscopy: II. Ion irradiated Au-Si Schottky junctions

    Laird, J S; Jagadish, C; Jamieson, D N; Legge, G J F

    2006-01-01

    Here we introduce a new technique called scanning ion deep level transient spectroscopy (SIDLTS) for the spatial analysis of electrically active defects in devices. In the first part of this paper, a simple theory behind SIDLTS was introduced and factors determining its sensitivity and resolution were discussed. In this paper, we demonstrate the technique on MeV boron implantation induced defects in an Au-Si Schottky junction. SIDLTS measurements are compared with capacitance DLTS measurements over the temperature range, 100-300 K. SIDLTS analyses indicate the presence of two levels, one of which was positively identified as the E c - 0.23 eV divacancy level. The high sensitivity of SIDLTS is verified and the advantages and limitations of the technique are discussed in light of non-exponential components in the charge transient response. Reasons for several undetected levels are also discussed

  14. Effect of deep dislocation levels in silicon on the properties of p-n junctions

    Zakharov, A.G.; Dudko, V.G.; Nabokov, G.M.; Sechenov, D.A.

    1988-07-01

    We present the results of studies on the influence of deep levels, due to dislocations in electronic-grade silicon, on the lifetime of minority carriers and on the current-voltage and capacitance-voltage characteristics of p-n junctions. The parameters of the deep levels were determined by means of dynamic spectroscopy. The carrier lifetime in the high-resistance region of the p-n junction correlates well with the dislocation density and varies from 10/sup /minus/7/ sec to 3 /centered dot/10/sup /minus/6/ sec when the dislocation density N/sub d/ varies from 10/sup 7/ cm/sup /minus/2/ to 5 /centered dot/10/sup 3/ cm/sup /minus/2/. The voltage across the p-n junction at a high level of injection varies 1.6 to 6.2 v as a function of N/sub d/. The ionization energy of deep levels associated with dislocation in silicon is 0.44 and 0.57 eV, measured from the bottom of the conduction band.

  15. A novel capacitive micro-accelerometer with grid strip capacitances and sensing gap alterable capacitances

    Dong Linxi; Chen Jindan; Huo Weihong; Li Yongjie; Sun Lingling; Yan Haixia

    2009-01-01

    The comb capacitances fabricated by deep reactive ion etching (RIE) process have high aspect ratio which is usually smaller than 30: 1 for the complicated process factors, and the combs are usually not parallel due to the well-known micro-loading effect and other process factors, which restricts the increase of the seismic mass by increasing the thickness of comb to reduce the thermal mechanical noise and the decrease of the gap of the comb capacitances for increasing the sensitive capacitance to reduce the electrical noise. Aiming at the disadvantage of the deep RIE, a novel capacitive micro-accelerometer with grid strip capacitances and sensing gap alterable capacitances is developed. One part of sensing of inertial signal of the micro-accelerometer is by the grid strip capacitances whose overlapping area is variable and which do not have the non-parallel plate's effect caused by the deep RIE process. Another part is by the sensing gap alterable capacitances whose gap between combs can be reduced by the actuators. The designed initial gap of the alterable comb capacitances is relatively large to depress the effect of the maximum aspect ratio (30 : 1) of deep RIE process. The initial gap of the capacitance of the actuator is smaller than the one of the comb capacitances. The difference between the two gaps is the initial gap of the sensitive capacitor. The designed structure depresses greatly the requirement of deep RIE process. The effects of non-parallel combs on the accelerometer are also analyzed. The characteristics of the micro-accelerometer are discussed by field emission microscopy (FEM) tool ANSYS. The tested devices based on slide-film damping effect are fabricated, and the tested quality factor is 514, which shows that grid strip capacitance design can partly improve the resolution and also prove the feasibility of the designed silicon-glass anodically bonding process.

  16. Tutorial: Junction spectroscopy techniques and deep-level defects in semiconductors

    Peaker, A. R.; Markevich, V. P.; Coutinho, J.

    2018-04-01

    The term junction spectroscopy embraces a wide range of techniques used to explore the properties of semiconductor materials and semiconductor devices. In this tutorial review, we describe the most widely used junction spectroscopy approaches for characterizing deep-level defects in semiconductors and present some of the early work on which the principles of today's methodology are based. We outline ab-initio calculations of defect properties and give examples of how density functional theory in conjunction with formation energy and marker methods can be used to guide the interpretation of experimental results. We review recombination, generation, and trapping of charge carriers associated with defects. We consider thermally driven emission and capture and describe the techniques of Deep Level Transient Spectroscopy (DLTS), high resolution Laplace DLTS, admittance spectroscopy, and scanning DLTS. For the study of minority carrier related processes and wide gap materials, we consider Minority Carrier Transient Spectroscopy (MCTS), Optical DLTS, and deep level optical transient spectroscopy together with some of their many variants. Capacitance, current, and conductance measurements enable carrier exchange processes associated with the defects to be detected. We explain how these methods are used in order to understand the behaviour of point defects and the determination of charge states and negative-U (Hubbard correlation energy) behaviour. We provide, or reference, examples from a wide range of materials including Si, SiGe, GaAs, GaP, GaN, InGaN, InAlN, and ZnO.

  17. Deep levels induced by low energy B+ implantation into Ge-preamorphised silicon in correlation with end of range formation

    Benzohra, Mohamed; Olivie, Francois; Idrissi-Benzohra, Malika; Ketata, Kaouther; Ketata, Mohamed

    2002-01-01

    It is well established that low energy B + ion implantation into Ge- (or Si) implantation pre-amorphised silicon allows ultra-shallow p + n junctions formation. However, this process is known to generate defects such as dislocation loops, vacancies and interstitials which can act as vehicles to different mechanisms inducing electrically active levels into the silicon bulk. The junctions studied have been obtained using 3 keV/10 15 cm -2 B + implantation into Ge-implantation pre-amorphised substrates and into a reference crystalline substrate. Accurate measurements using deep level transient spectroscopy (DLTS) and isothermal transient capacitance ΔC(t,T) were performed to characterise these levels. Such knowledge is crucial to improve the device characteristics. In order to sweep the silicon band gap, various experimental conditions were considered. The analysis of DLTS spectra have first showed three deep levels associated to secondary induced defects. Their concentration profiles were derived from isothermal transient capacitance at depths up to 3.5 μm into the silicon bulk and allowed us to detect a new deep level. The evolution of such defect distribution in correlation with the technological steps is discussed. The end of range (EOR) defect influence on electrical activity of secondary induced defects in ultra-shallow p + n diodes is clearly demonstrated

  18. Sputtered Encapsulation as Wafer Level Packaging for Isolatable MEMS Devices: A Technique Demonstrated on a Capacitive Accelerometer

    Azrul Azlan Hamzah

    2008-11-01

    Full Text Available This paper discusses sputtered silicon encapsulation as a wafer level packaging approach for isolatable MEMS devices. Devices such as accelerometers, RF switches, inductors, and filters that do not require interaction with the surroundings to function, could thus be fully encapsulated at the wafer level after fabrication. A MEMSTech 50g capacitive accelerometer was used to demonstrate a sputtered encapsulation technique. Encapsulation with a very uniform surface profile was achieved using spin-on glass (SOG as a sacrificial layer, SU-8 as base layer, RF sputtered silicon as main structural layer, eutectic gold-silicon as seal layer, and liquid crystal polymer (LCP as outer encapsulant layer. SEM inspection and capacitance test indicated that the movable elements were released after encapsulation. Nanoindentation test confirmed that the encapsulated device is sufficiently robust to withstand a transfer molding process. Thus, an encapsulation technique that is robust, CMOS compatible, and economical has been successfully developed for packaging isolatable MEMS devices at the wafer level.

  19. The role of deep level traps in barrier height of 4H-SiC Schottky diode

    Zaremba, G., E-mail: gzaremba@ite.waw.pl [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Adamus, Z. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Jung, W.; Kaminska, E.; Borysiewicz, M.A.; Korwin-Mikke, K. [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)

    2012-09-01

    This paper presents a discussion about the influence of deep level defects on the height of Ni-Si based Schottky barriers to 4H-SiC. The defects were characterized by deep level transient spectroscopy (DLTS) in a wide range of temperatures (78-750 K). The numerical simulation of barrier height value as a function of dominant defect concentration was carried out to estimate concentration, necessary to 'pin' Fermi level and thus significantly influence the barrier height. From comparison of the results of simulation with barrier height values obtained by capacitance-voltage (C-V) measurements it seems that dominant defect in measured concentration has a very small impact on the barrier height and on the increase of reverse current.

  20. Investigation of deep levels in GaInNAs

    Abulfotuh, F.; Balcioglu, A.; Friedman, D.; Geisz, J.; Kurtz, S.

    1999-01-01

    This paper presents and discusses the first Deep-Level transient spectroscopy (DLTS) data obtained from measurements carried out on both Schottky barriers and homojunction devices of GaInNAs. The effect of N and In doping on the electrical properties of the GaNInAs devices, which results in structural defects and interface states, has been investigated. Moreover, the location and densities of deep levels related to the presence of N, In, and N+In are identified and correlated with the device performance. The data confirmed that the presence of N alone creates a high density of shallow hole traps related to the N atom and structural defects in the device. Doping by In, if present alone, also creates low-density deep traps (related to the In atom and structural defects) and extremely deep interface states. On the other hand, the co-presence of In and N eliminates both the interface states and levels related to structural defects. However, the device still has a high density of the shallow and deep traps that are responsible for the photocurrent loss in the GaNInAs device, together with the possible short diffusion length. copyright 1999 American Institute of Physics

  1. Investigation of Deep Levels in GaInNas

    Balcioglu, A.; Friedman, D.; Abulfotuh, F.; Geisz, J.; Kurtz, S.

    1998-01-01

    This paper presents and discusses the first Deep-Level transient spectroscopy (DLTS) data obtained from measurements carried out on both Schottky barriers and homojunction devices of GaInNAs. The effect of N and In doping on the electrical properties of the GaNInAs devices, which results in structural defects and interface states, has been investigated. Moreover, the location and densities of deep levels related to the presence of N, In, and N+In are identified and correlated with the device performance. The data confirmed that the presence of N alone creates a high density of shallow hole traps related to the N atom and structural defects in the device. Doping by In, if present alone, also creates low-density deep traps (related to the In atom and structural defects) and extremely deep interface states. On the other hand, the co-presence of In and N eliminates both the interface states and levels related to structural defects. However, the device still has a high density of the shallow and deep traps that are responsible for the photocurrent loss in the GaNInAs device, together with the possible short diffusion length

  2. The Deep-Level-Reasoning-Question Effect: The Role of Dialogue and Deep-Level-Reasoning Questions during Vicarious Learning

    Craig, Scotty D.; Sullins, Jeremiah; Witherspoon, Amy; Gholson, Barry

    2006-01-01

    We investigated the impact of dialogue and deep-level-reasoning questions on vicarious learning in 2 studies with undergraduates. In Experiment 1, participants learned material by interacting with AutoTutor or by viewing 1 of 4 vicarious learning conditions: a noninteractive recorded version of the AutoTutor dialogues, a dialogue with a…

  3. Deep borehole disposal of high-level radioactive waste.

    Stein, Joshua S.; Freeze, Geoffrey A.; Brady, Patrick Vane; Swift, Peter N.; Rechard, Robert Paul; Arnold, Bill Walter; Kanney, Joseph F.; Bauer, Stephen J.

    2009-07-01

    Preliminary evaluation of deep borehole disposal of high-level radioactive waste and spent nuclear fuel indicates the potential for excellent long-term safety performance at costs competitive with mined repositories. Significant fluid flow through basement rock is prevented, in part, by low permeabilities, poorly connected transport pathways, and overburden self-sealing. Deep fluids also resist vertical movement because they are density stratified. Thermal hydrologic calculations estimate the thermal pulse from emplaced waste to be small (less than 20 C at 10 meters from the borehole, for less than a few hundred years), and to result in maximum total vertical fluid movement of {approx}100 m. Reducing conditions will sharply limit solubilities of most dose-critical radionuclides at depth, and high ionic strengths of deep fluids will prevent colloidal transport. For the bounding analysis of this report, waste is envisioned to be emplaced as fuel assemblies stacked inside drill casing that are lowered, and emplaced using off-the-shelf oilfield and geothermal drilling techniques, into the lower 1-2 km portion of a vertical borehole {approx}45 cm in diameter and 3-5 km deep, followed by borehole sealing. Deep borehole disposal of radioactive waste in the United States would require modifications to the Nuclear Waste Policy Act and to applicable regulatory standards for long-term performance set by the US Environmental Protection Agency (40 CFR part 191) and US Nuclear Regulatory Commission (10 CFR part 60). The performance analysis described here is based on the assumption that long-term standards for deep borehole disposal would be identical in the key regards to those prescribed for existing repositories (40 CFR part 197 and 10 CFR part 63).

  4. Study and microscopic characterization of the cadmium telluride deep levels

    Biglari, B.

    1989-05-01

    The spectroscopic methods PICTS, QTS and CTS were developed and perfected to investigate deep level analysis of high resistivity CdTe crystals which were either undoped, or doped with chlorine and copper. Crystals which were grown in space were also investigated. The main characterization of defect levels was determined and different correlations were established between the material's resistivity, chemical residues, dopant concentration and the nuclear radiation detector parameters. Using PICTS and CTS techniques, the generation of defects, under strong gamma-ray irradiation and particle bombardment was also studied. The influence of hydrogen on the main electrical characteristics of CdTe, in particular its ability to passivate the electrical activity of many deep defect and impurity states have been demonstrated. The compensation effects of Cl, Cu and H + are interpreted using the qualitative models based on different possibilities of pairing or triplet formation between the ions of these dopants and those of defects [fr

  5. Deep subcritical levels measurements dependents upon kinetic distortion factors

    Pan Shibiao; Li Xiang; Fu Guo'en; Huang Liyuan; Mu Keliang

    2013-01-01

    The measurement of deep subcritical levels, with the increase of subcriticality, showed that the results impact on the kinetic distortion effect, along with neutron flux strongly deteriorated. Using the diffusion theory, calculations have been carried out to quantify the kinetic distortion correction factors in subcritical systems, and these indicate that epithermal neutron distributions are strongly affected by kinetic distortion. Subcriticality measurements in four different rod-state combination at the zero power device was carried out. The test data analysis shows that, with increasing subcriticality, kinetic distortion effect correction factor gradually increases from 1.052 to 1.065, corresponding reactive correction amount of 0.78β eff ∼ 3.01β eff . Thus, it is necessary to consider the kinetic distortion effect in the deep subcritical reactivity measurements. (authors)

  6. High resolution deep level transient spectroscopy and process-induced defects in silicon

    Evans-Freeman, J.H.; Emiroglu, D.; Vernon-Parry, K.D.

    2004-01-01

    High resolution, or Laplace, deep level transient spectroscopy (LDLTS) enables the identification of very closely spaced energetic levels in a semiconductor bandgap. DLTS may resolve peaks with a separation of tens of electron volts, but LDLTS can resolve defect energy separations as low as a few MeV. In this paper, we present results from LDLTS applied to ion implantation-induced defects in silicon, with particular emphasis on characterisation of end-of-range interstitial type defects. Silicon was implanted with a variety of ions from mass 28 to 166. A combination of LDLTS and direct capture cross-section measurements was employed to show that electrically active small extended defects were present in the as-implanted samples. Larger dislocations were then generated in Si by oxygenation to act as a control sample. These stacking faults had typical lengths of microns, and their electrical activity was subsequently characterised by LDLTS. This was to establish the sensitivity of LDLTS to defects whose carrier capture is characterised by a non-exponential filling process and an evolving band structure as carrier capture proceeds. The LDLTS spectra show several components in capacitance transients originating from both the end-of-range defects, and the stacking faults, and also clearly show that the carrier emission rates reduce as these extended defects fill with carriers. The end-of-range defects and the stacking faults are shown to have the same electrical behaviour

  7. Scanning ion deep level transient spectroscopy: I. Theory

    Laird, J S; Jagadish, C; Jamieson, D N; Legge, G J F

    2006-01-01

    Theoretical aspects of a new technique for the MeV ion microbeam are described in detail for the first time. The basis of the technique, termed scanning ion deep level transient spectroscopy (SIDLTS), is the imaging of defect distributions within semiconductor devices. The principles of SIDLTS are similar to those behind other deep level transient spectroscopy (DLTS) techniques with the main difference stemming from the injection of carriers into traps using the localized energy-loss of a focused MeV ion beam. Energy-loss of an MeV ion generates an electron-hole pair plasma, providing the equivalent of a DLTS trap filling pulse with a duration which depends on space-charge screening of the applied electric field and ambipolar erosion of the plasma for short ranging ions. Some nanoseconds later, the detrapping current transient is monitored as a charge transient. Scanning the beam in conjunction with transient analysis allows the imaging of defect levels. As with DLTS, the temperature dependence of the transient can be used to extract trap activation levels. In this, the first of a two-part paper, we introduce the various stages of corner capture and derive a simple expression for the observed charge transient. The second paper will illustrate the technique on a MeV ion implanted Au-Si Schottky junction

  8. Growth temperature dependence of Si doping efficiency and compensating deep level defect incorporation in Al0.7Ga0.3N

    Armstrong, Andrew M.; Moseley, Michael W.; Allerman, Andrew A.; Crawford, Mary H.; Wierer, Jonathan J.

    2015-01-01

    The growth temperature dependence of Si doping efficiency and deep level defect formation was investigated for n-type Al 0.7 Ga 0.3 N. It was observed that dopant compensation was greatly reduced with reduced growth temperature. Deep level optical spectroscopy and lighted capacitance-voltage were used to understand the role of acceptor-like deep level defects on doping efficiency. Deep level defects were observed at 2.34 eV, 3.56 eV, and 4.74 eV below the conduction band minimum. The latter two deep levels were identified as the major compensators because the reduction in their concentrations at reduced growth temperature correlated closely with the concomitant increase in free electron concentration. Possible mechanisms for the strong growth temperature dependence of deep level formation are considered, including thermodynamically driven compensating defect formation that can arise for a semiconductor with very large band gap energy, such as Al 0.7 Ga 0.3 N

  9. Multi-level deep supervised networks for retinal vessel segmentation.

    Mo, Juan; Zhang, Lei

    2017-12-01

    Changes in the appearance of retinal blood vessels are an important indicator for various ophthalmologic and cardiovascular diseases, including diabetes, hypertension, arteriosclerosis, and choroidal neovascularization. Vessel segmentation from retinal images is very challenging because of low blood vessel contrast, intricate vessel topology, and the presence of pathologies such as microaneurysms and hemorrhages. To overcome these challenges, we propose a neural network-based method for vessel segmentation. A deep supervised fully convolutional network is developed by leveraging multi-level hierarchical features of the deep networks. To improve the discriminative capability of features in lower layers of the deep network and guide the gradient back propagation to overcome gradient vanishing, deep supervision with auxiliary classifiers is incorporated in some intermediate layers of the network. Moreover, the transferred knowledge learned from other domains is used to alleviate the issue of insufficient medical training data. The proposed approach does not rely on hand-crafted features and needs no problem-specific preprocessing or postprocessing, which reduces the impact of subjective factors. We evaluate the proposed method on three publicly available databases, the DRIVE, STARE, and CHASE_DB1 databases. Extensive experiments demonstrate that our approach achieves better or comparable performance to state-of-the-art methods with a much faster processing speed, making it suitable for real-world clinical applications. The results of cross-training experiments demonstrate its robustness with respect to the training set. The proposed approach segments retinal vessels accurately with a much faster processing speed and can be easily applied to other biomedical segmentation tasks.

  10. High-level radioactive waste disposal in the deep ocean

    Hill, H.W.

    1977-01-01

    A joint programme has begun between the Fisheries Laboratory, Lowestoft and the Institute of Oceanographic Sciences, Wormley to study the dispersion of radioactivity in the deep ocean arising from the possible dumping of high level waste on the sea bed in vitrified-glass form which would permit slow leakage over a long term scale. The programme consists firstly of the development of a simple diffusion/advection model for the dispersion of radioactivity in a closed and finite ocean, which overcomes many of the criticisms of the earlier model proposed by Webb and Morley. Preliminary results from this new model are comparable to those of the Webb-Morley model for radio isotopes with half-lives of 10-300 years but are considerably more restrictive outside this range, particularly for those which are much longer-lived. The second part of the programme, towards which the emphasis is directed, concerns the field programme planned to measure the advection and diffusion parameters in the deeper layers of the ocean to provide realistic input parameters to the model and increase our fundamental understanding of the environment in which the radioactive materials may be released. The first cruises of the programme will take place in late 1976 and involve deep current meter deployments and float dispersion experiments around the present NEA dump site with some sediment sampling, so that adsorption experiments can be started on typical deep sea sediments. The programme will expand the number of long-term deep moored stations over the next five years and include further float experiments, CTD profiling, and other physical oceanography. In the second half of the 5-year programme, attempts will be made to measure diffusion parameters in the deeper layers of the ocean using radioactive tracers

  11. Deep impurity levels in n-type copper oxides

    Ovchinnikov, S.G.

    1994-01-01

    The density of Nd 2-x Ce x CuO 4 monoparticle states was calculated by the method of precise diagonalization of multielectron hamiltonian of 6-zone model for CuO cluster. Emergence of a deep impurity state of a symmetry in the middle of dielectric slit, which is a mixture of d z 2-states of copper and a 1 -molecular orbital of oxygen, is shown. Fluctuation of parameters of p-d jump and energies of charge transfer provide additional fine impurity levels near the bottom of conductivity zone and ceiling of valency zone. 30 refs., 4 figs

  12. Human-level control through deep reinforcement learning

    Mnih, Volodymyr; Kavukcuoglu, Koray; Silver, David; Rusu, Andrei A.; Veness, Joel; Bellemare, Marc G.; Graves, Alex; Riedmiller, Martin; Fidjeland, Andreas K.; Ostrovski, Georg; Petersen, Stig; Beattie, Charles; Sadik, Amir; Antonoglou, Ioannis; King, Helen; Kumaran, Dharshan; Wierstra, Daan; Legg, Shane; Hassabis, Demis

    2015-02-01

    The theory of reinforcement learning provides a normative account, deeply rooted in psychological and neuroscientific perspectives on animal behaviour, of how agents may optimize their control of an environment. To use reinforcement learning successfully in situations approaching real-world complexity, however, agents are confronted with a difficult task: they must derive efficient representations of the environment from high-dimensional sensory inputs, and use these to generalize past experience to new situations. Remarkably, humans and other animals seem to solve this problem through a harmonious combination of reinforcement learning and hierarchical sensory processing systems, the former evidenced by a wealth of neural data revealing notable parallels between the phasic signals emitted by dopaminergic neurons and temporal difference reinforcement learning algorithms. While reinforcement learning agents have achieved some successes in a variety of domains, their applicability has previously been limited to domains in which useful features can be handcrafted, or to domains with fully observed, low-dimensional state spaces. Here we use recent advances in training deep neural networks to develop a novel artificial agent, termed a deep Q-network, that can learn successful policies directly from high-dimensional sensory inputs using end-to-end reinforcement learning. We tested this agent on the challenging domain of classic Atari 2600 games. We demonstrate that the deep Q-network agent, receiving only the pixels and the game score as inputs, was able to surpass the performance of all previous algorithms and achieve a level comparable to that of a professional human games tester across a set of 49 games, using the same algorithm, network architecture and hyperparameters. This work bridges the divide between high-dimensional sensory inputs and actions, resulting in the first artificial agent that is capable of learning to excel at a diverse array of challenging tasks.

  13. Human-level control through deep reinforcement learning.

    Mnih, Volodymyr; Kavukcuoglu, Koray; Silver, David; Rusu, Andrei A; Veness, Joel; Bellemare, Marc G; Graves, Alex; Riedmiller, Martin; Fidjeland, Andreas K; Ostrovski, Georg; Petersen, Stig; Beattie, Charles; Sadik, Amir; Antonoglou, Ioannis; King, Helen; Kumaran, Dharshan; Wierstra, Daan; Legg, Shane; Hassabis, Demis

    2015-02-26

    The theory of reinforcement learning provides a normative account, deeply rooted in psychological and neuroscientific perspectives on animal behaviour, of how agents may optimize their control of an environment. To use reinforcement learning successfully in situations approaching real-world complexity, however, agents are confronted with a difficult task: they must derive efficient representations of the environment from high-dimensional sensory inputs, and use these to generalize past experience to new situations. Remarkably, humans and other animals seem to solve this problem through a harmonious combination of reinforcement learning and hierarchical sensory processing systems, the former evidenced by a wealth of neural data revealing notable parallels between the phasic signals emitted by dopaminergic neurons and temporal difference reinforcement learning algorithms. While reinforcement learning agents have achieved some successes in a variety of domains, their applicability has previously been limited to domains in which useful features can be handcrafted, or to domains with fully observed, low-dimensional state spaces. Here we use recent advances in training deep neural networks to develop a novel artificial agent, termed a deep Q-network, that can learn successful policies directly from high-dimensional sensory inputs using end-to-end reinforcement learning. We tested this agent on the challenging domain of classic Atari 2600 games. We demonstrate that the deep Q-network agent, receiving only the pixels and the game score as inputs, was able to surpass the performance of all previous algorithms and achieve a level comparable to that of a professional human games tester across a set of 49 games, using the same algorithm, network architecture and hyperparameters. This work bridges the divide between high-dimensional sensory inputs and actions, resulting in the first artificial agent that is capable of learning to excel at a diverse array of challenging tasks.

  14. Preliminary analyses of the deep geoenvironmental characteristics for the deep borehole disposal of high-level radioactive waste in Korea

    Lee, Jong Youl; Lee, Min Soo; Choi, Heui Joo; Kim, Geon Young; Kim, Kyung Su [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-06-15

    Spent fuels from nuclear power plants, as well as high-level radioactive waste from the recycling of spent fuels, should be safely isolated from human environment for an extremely long time. Recently, meaningful studies on the development of deep borehole radioactive waste disposal system in 3-5 km depth have been carried out in USA and some countries in Europe, due to great advance in deep borehole drilling technology. In this paper, domestic deep geoenvironmental characteristics are preliminarily investigated to analyze the applicability of deep borehole disposal technology in Korea. To do this, state-of-the art technologies in USA and some countries in Europe are reviewed, and geological and geothermal data from the deep boreholes for geothermal usage are analyzed. Based on the results on the crystalline rock depth, the geothermal gradient and the spent fuel types generated in Korea, a preliminary deep borehole concept including disposal canister and sealing system, is suggested.

  15. Preliminary analyses of the deep geoenvironmental characteristics for the deep borehole disposal of high-level radioactive waste in Korea

    Lee, Jong Youl; Lee, Min Soo; Choi, Heui Joo; Kim, Geon Young; Kim, Kyung Su

    2016-01-01

    Spent fuels from nuclear power plants, as well as high-level radioactive waste from the recycling of spent fuels, should be safely isolated from human environment for an extremely long time. Recently, meaningful studies on the development of deep borehole radioactive waste disposal system in 3-5 km depth have been carried out in USA and some countries in Europe, due to great advance in deep borehole drilling technology. In this paper, domestic deep geoenvironmental characteristics are preliminarily investigated to analyze the applicability of deep borehole disposal technology in Korea. To do this, state-of-the art technologies in USA and some countries in Europe are reviewed, and geological and geothermal data from the deep boreholes for geothermal usage are analyzed. Based on the results on the crystalline rock depth, the geothermal gradient and the spent fuel types generated in Korea, a preliminary deep borehole concept including disposal canister and sealing system, is suggested

  16. Influence of oxidation level on capacitance of electrochemical capacitors fabricated with carbon nanotube/carbon paper composites

    Hsieh, C.-T.; Chen, W.-Y.; Cheng, Y.-S.

    2010-01-01

    Gaseous oxidation of carbon papers (CPs) decorated with carbon nanotubes (CNTs) with varying degrees of oxidation was conducted to investigate the influence of surface oxides on the performance of electrochemical capacitors fabricated with oxidized CNT/CP composites. The oxidation period was found to significantly enhance the O/C atomic ratio on the composites, and the increase in oxygen content upon oxidation is mainly contributed by the formation of C=O and C-O groups. The electrochemical behavior of the capacitors was tested in 1 M H 2 SO 4 within a potential of 0 and 1 V vs. Ag/AgCl. Both superhydrophilicity and specific capacitance of the oxidized CNT/CP composites were found to increase upon oxidation treatment. A linearity increase of capacitance with O/C ratio can be attributed to the increase of the population of surface oxides on CNTs, which imparts excess sites for redox reaction (pseudocapacitance) and for the formation of double-layer (double-layer capacitance). The technique of ac impedance combined with equivalent circuit clearly showed that oxidized CNT/CP capacitor imparts not only enhanced capacitance but also a low equivalent series resistance.

  17. Rapid capacitive detection of femtomolar levels of bisphenol A using an aptamer-modified disposable microelectrode array

    Cui, Haochen; Wu, Jayne; Eda, Shigetoshi; Chen, Jiangang; Chen, Wei; Zheng, Lei

    2015-01-01

    A label-free and single-step method is reported for rapid and highly sensitive detection of bisphenol A (BPA) in aqueous samples. It utilizes an aptamer acting as a probe molecule immobilized on a commercially available array of interdigitated aluminum microelectrodes. BPA was quantified by measuring the interfacial capacitance change rate caused by the specific binding between bisphenol A and the immobilized aptamer. The AC signal also induces an AC electrokinetic effect to generate microfluidic motion for enhanced binding. The capacitive aptasensor achieves a limit of detection as low as 10 fM(2.8 fg ⋅ mL −1 ) with a 20 s response time. The method is inexpensive, highly sensitive, rapid and therefore provides a promising technology for on-site detection of BPA in food and water samples. (author)

  18. Effect of swift heavy ion irradiation on deep levels in Au /n-Si (100) Schottky diode studied by deep level transient spectroscopy

    Kumar, Sandeep; Katharria, Y. S.; Kumar, Sugam; Kanjilal, D.

    2007-12-01

    In situ deep level transient spectroscopy has been applied to investigate the influence of 100MeV Si7+ ion irradiation on the deep levels present in Au/n-Si (100) Schottky structure in a wide fluence range from 5×109to1×1012ions cm-2. The swift heavy ion irradiation introduces a deep level at Ec-0.32eV. It is found that initially, trap level concentration of the energy level at Ec-0.40eV increases with irradiation up to a fluence value of 1×1010cm-2 while the deep level concentration decreases as irradiation fluence increases beyond the fluence value of 5×1010cm-2. These results are discussed, taking into account the role of energy transfer mechanism of high energy ions in material.

  19. Impact of the silicon substrate resistivity and growth condition on the deep levels in Ni-Au/AlN/Si MIS Capacitors

    Wang, Chong; Simoen, Eddy; Zhao, Ming; Li, Wei

    2017-10-01

    Deep levels formed under different growth conditions of a 200 nm AlN buffer layer on B-doped Czochralski Si(111) substrates with different resistivity were investigated by deep-level transient spectroscopy (DLTS) on metal-insulator-semiconductor capacitors. Growth-temperature-dependent Al diffusion in the Si substrate was derived from the free carrier density obtained by capacitance-voltage measurement on samples grown on p- substrates. The DLTS spectra revealed a high concentration of point and extended defects in the p- and p+ silicon substrates, respectively. This indicated a difference in the electrically active defects in the silicon substrate close to the AlN/Si interface, depending on the B doping concentration.

  20. Convolutional Neural Networks for Text Categorization: Shallow Word-level vs. Deep Character-level

    Johnson, Rie; Zhang, Tong

    2016-01-01

    This paper reports the performances of shallow word-level convolutional neural networks (CNN), our earlier work (2015), on the eight datasets with relatively large training data that were used for testing the very deep character-level CNN in Conneau et al. (2016). Our findings are as follows. The shallow word-level CNNs achieve better error rates than the error rates reported in Conneau et al., though the results should be interpreted with some consideration due to the unique pre-processing o...

  1. Low energy electron irradiation induced deep level defects in 6H-SiC: The implication for the microstructure of the deep levels E1/E2

    Chen, X.D.; Fung, S.; Beling, C.D.; Lui, M.K.; Ling, C.C.; Yang, C.L.; Ge, W.K.; Wang, J.N.; Gong, M.

    2004-01-01

    N-type 6H-SiC samples irradiated with electrons having energies of E e =0.2, 0.3, 0.5, and 1.7 were studied by deep level transient technique. No deep level was detected at below 0.2 MeV irradiation energy while for E e ≥0.3 MeV, deep levels ED1, E 1 /E 2 , and E i appeared. By considering the minimum energy required to displace the C atom or the Si atom in the SiC lattice, it is concluded that generation of the deep levels E 1 /E 2 , as well as ED1 and E i , involves the displacement of the C atom in the SiC lattice

  2. Surface-Level Diversity and Decision-Making in Groups: When Does Deep-Level Similarity Help?

    2006-01-01

    Abstract We examined how surface-level diversity (based on race) and deep-level similarities influenced three-person decision-making groups on a hidden-profile task. Surface-level homogeneous groups perceived their information to be less unique and spent less time on the task than surface-level diverse groups. When the groups were given the opportunity to learn about their deep-level similarities prior to t...

  3. False capacitance of supercapacitors

    Ragoisha, G. A.; Aniskevich, Y. M.

    2016-01-01

    Capacitance measurements from cyclic voltammetry, galvanostatic chronopotentiometry and calculation of capacitance from imaginary part of impedance are widely used in investigations of supercapacitors. The methods assume the supercapacitor is a capacitor, while real objects correspond to different equivalent electric circuits and show various contributions of non-capacitive currents to the current which is used for calculation of capacitance. Specific capacitances which are presented in F g-1...

  4. Decadal trends in deep ocean salinity and regional effects on steric sea level

    Purkey, S. G.; Llovel, W.

    2017-12-01

    We present deep (below 2000 m) and abyssal (below 4000 m) global ocean salinity trends from the 1990s through the 2010s and assess the role of deep salinity in local and global sea level budgets. Deep salinity trends are assessed using all deep basins with available full-depth, high-quality hydrographic section data that have been occupied two or more times since the 1980s through either the World Ocean Circulation Experiment (WOCE) Hydrographic Program or the Global Ship-Based Hydrographic Investigations Program (GO-SHIP). All salinity data is calibrated to standard seawater and any intercruise offsets applied. While the global mean deep halosteric contribution to sea level rise is close to zero (-0.017 +/- 0.023 mm/yr below 4000 m), there is a large regional variability with the southern deep basins becoming fresher and northern deep basins becoming more saline. This meridional gradient in the deep salinity trend reflects different mechanisms driving the deep salinity variability. The deep Southern Ocean is freshening owing to a recent increased flux of freshwater to the deep ocean. Outside of the Southern Ocean, the deep salinity and temperature changes are tied to isopycnal heave associated with a falling of deep isopycnals in recent decades. Therefore, regions of the ocean with a deep salinity minimum are experiencing both a halosteric contraction with a thermosteric expansion. While the thermosteric expansion is larger in most cases, in some regions the halosteric compensates for as much as 50% of the deep thermal expansion, making a significant contribution to local sea level rise budgets.

  5. Using Deep Learning Techniques to Forecast Environmental Consumption Level

    Donghyun Lee

    2017-10-01

    Full Text Available Artificial intelligence is a promising futuristic concept in the field of science and technology, and is widely used in new industries. The deep-learning technology leads to performance enhancement and generalization of artificial intelligence technology. The global leader in the field of information technology has declared its intention to utilize the deep-learning technology to solve environmental problems such as climate change, but few environmental applications have so far been developed. This study uses deep-learning technologies in the environmental field to predict the status of pro-environmental consumption. We predicted the pro-environmental consumption index based on Google search query data, using a recurrent neural network (RNN model. To verify the accuracy of the index, we compared the prediction accuracy of the RNN model with that of the ordinary least square and artificial neural network models. The RNN model predicts the pro-environmental consumption index better than any other model. We expect the RNN model to perform still better in a big data environment because the deep-learning technologies would be increasingly sophisticated as the volume of data grows. Moreover, the framework of this study could be useful in environmental forecasting to prevent damage caused by climate change.

  6. The calculation of deep levels in semiconductors by using a recursion method for super-cells

    Wong Yongliang.

    1987-01-01

    The paper presents the theory of deep levels in semiconductors, the super-cell approach to the theory of deep level impurities, the calculation of band structure by using the tight-binding method and the recursion method used to study the defects in the presence of lattice relaxation and extended defect complexes. 47 refs

  7. DLTS and capacitance transients study of defects induced by neutron irradiation in MOS structures CCD process

    Ahaitouf, A.; Losson, E.; Charles, J.P.

    1999-01-01

    The aim of this paper is to study neutron irradiation effects on PMOS capacitors and NMOSFETs transistors. The characterization of induced defects was made by capacitance transients C(t) measurements, DLTS spectroscopy, and optical DLTS (ODLTS). DLTS spectra present three peaks due to deep levels created in the semiconductor and two peaks due to minority carrier generation. Two levels are reported in the literature. Two other minority carrier traps have been observed on ODLTS spectra after irradiation. This can explain the decrease of the minority carrier generation lifetime observed by capacitance transients measurements. (authors)

  8. Application of positron annihilation lifetime technique to the study of deep level transients in semiconductors

    Deng, A. H.; Shan, Y. Y.; Fung, S.; Beling, C. D.

    2002-03-01

    Unlike its conventional applications in lattice defect characterization, positron annihilation lifetime technique was applied to study temperature-dependent deep level transients in semiconductors. Defect levels in the band gap can be determined as they are determined by conventional deep level transient spectroscopy (DLTS) studies. The promising advantage of this application of positron annihilation over the conventional DLTS is that it could further extract extra microstructure information of deep-level defects, such as whether a deep level defect is vacancy related or not. A demonstration of EL2 defect level transient study in GaAs was shown and the EL2 level of 0.82±0.02 eV was obtained by a standard Arrhenius analysis, similar to that in conventional DLTS studies.

  9. Deep Levels of Processing Elicit a Distinctiveness Heuristic: Evidence from the Criterial Recollection Task

    Gallo, David A.; Meadow, Nathaniel G.; Johnson, Elizabeth L.; Foster, Katherine T.

    2008-01-01

    Thinking about the meaning of studied words (deep processing) enhances memory on typical recognition tests, relative to focusing on perceptual features (shallow processing). One explanation for this levels-of-processing effect is that deep processing leads to the encoding of more distinctive representations (i.e., more unique semantic or…

  10. Deep-level transient spectroscopy on an amorphous InGaZnO4 Schottky diode

    Chasin, A.; Simoen, E.; Bhoolokam, A.; Nag, M.; Genoe, J.; Gielen, G.; Heremans, P.

    2014-01-01

    The first direct measurement is reported of the bulk density of deep states in amorphous IGZO (indium-gallium-zinc oxide) semiconductor by means of deep-level transient spectroscopy (DLTS). The device under test is a Schottky diode of amorphous IGZO semiconductor on a palladium (Pd) Schottky-barrier

  11. High temperature annealing effects on deep-level defects in a high purity semi-insulating 4H-SiC substrate

    Iwamoto, Naoya, E-mail: naoya.iwamoto@smn.uio.no; Azarov, Alexander; Svensson, Bengt G. [Department of Physics, Center for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Ohshima, Takeshi [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292 Gunma (Japan); Moe, Anne Marie M. [Washington Mills AS, N-7300 Orkanger (Norway)

    2015-07-28

    Effects of high-temperature annealing on deep-level defects in a high-purity semi-insulating 4H silicon carbide substrate have been studied by employing current-voltage, capacitance-voltage, junction spectroscopy, and chemical impurity analysis measurements. Secondary ion mass spectrometry data reveal that the substrate contains boron with concentration in the mid 10{sup 15 }cm{sup −3} range, while other impurities including nitrogen, aluminum, titanium, vanadium and chromium are below their detection limits (typically ∼10{sup 14 }cm{sup −3}). Schottky barrier diodes fabricated on substrates annealed at 1400–1700 °C exhibit metal/p-type semiconductor behavior with a current rectification of up to 8 orders of magnitude at bias voltages of ±3 V. With increasing annealing temperature, the series resistance of the Schottky barrier diodes decreases, and the net acceptor concentration in the substrates increases approaching the chemical boron content. Admittance spectroscopy results unveil the presence of shallow boron acceptors and deep-level defects with levels in lower half of the bandgap. After the 1400 °C annealing, the boron acceptor still remains strongly compensated at room temperature by deep donor-like levels located close to mid-gap. However, the latter decrease in concentration with increasing annealing temperature and after 1700 °C, the boron acceptor is essentially uncompensated. Hence, the deep donors are decisive for the semi-insulating properties of the substrates, and their thermal evolution limits the thermal budget for device processing. The origin of the deep donors is not well-established, but substantial evidence supporting an assignment to carbon vacancies is presented.

  12. Deep defect levels in standard and oxygen enriched silicon detectors before and after **6**0Co-gamma-irradiation

    Stahl, J; Lindström, G; Pintilie, I

    2003-01-01

    Capacitance Deep Level Transient Spectroscopy (C-DLTS) measurements have been performed on standard and oxygen-doped silicon detectors manufactured from high-resistivity n-type float zone material with left angle bracket 111 right angle bracket and left angle bracket 100 right angle bracket orientation. Three different oxygen concentrations were achieved by the so-called diffusion oxygenated float zone (DOFZ) process initiated by the CERN-RD48 (ROSE) collaboration. Before the irradiation a material characterization has been performed. In contrast to radiation damage by neutrons or high- energy charged hadrons, were the bulk damage is dominated by a mixture of clusters and point defects, the bulk damage caused by **6**0Co-gamma-radiation is only due to the introduction of point defects. The dominant electrically active defects which have been detected after **6**0Co-gamma-irradiation by C-DLTS are the electron traps VO//i, C//iC//s, V//2( = /-), V //2(-/0) and the hole trap C//i O//i. The main difference betwe...

  13. Setup for in situ deep level transient spectroscopy of semiconductors during swift heavy ion irradiation.

    Kumar, Sandeep; Kumar, Sugam; Katharria, Y S; Safvan, C P; Kanjilal, D

    2008-05-01

    A computerized system for in situ deep level characterization during irradiation in semiconductors has been set up and tested in the beam line for materials science studies of the 15 MV Pelletron accelerator at the Inter-University Accelerator Centre, New Delhi. This is a new facility for in situ irradiation-induced deep level studies, available in the beam line of an accelerator laboratory. It is based on the well-known deep level transient spectroscopy (DLTS) technique. High versatility for data manipulation is achieved through multifunction data acquisition card and LABVIEW. In situ DLTS studies of deep levels produced by impact of 100 MeV Si ions on Aun-Si(100) Schottky barrier diode are presented to illustrate performance of the automated DLTS facility in the beam line.

  14. Characterization of defects in hydrogenated amorphous silicon deposited on different substrates by capacitance techniques

    Darwich, R.; Roca i Cabarrocas, P.

    2011-01-01

    Hydrogenated amorphous silicon (a-Si:H) thin films deposited on crystalline silicon and Corning glass substrate were analyzed using different capacitance techniques. The distribution of localized states and some electronic properties were studied using the temperature, frequency and bias dependence of the Schottky barrier capacitance and deep level transient spectroscopy. Our results show that the distribution of the gap states depends on the type of substrate. We have found that the films deposited on c-Si substrate represent only one positively charged or prerelaxed neutral deep state and one interface state, while the films deposited on glass substrate have one interface state and three types of deep defect states, positively or prerelaxed neutral, neutral and negatively charged.

  15. The capacitance of Pt/Pb0.65La0.28Ti0.96O3/Pt structures

    Shaw, T.M.; Laibowitz, R.B.; Beach, D.; Duncombe, P.R.

    1996-01-01

    The capacitance/voltage characteristics of thin paraelectric lead lanthanum titanate films are measured using platinum electrodes. The films have a maximum capacitance when either a small positive or negative bias voltage is applied. This characteristic is consistent with the electrode interfaces acting as Schottky-like barriers. The voltage at which the capacitance maxima occur increases linearly with film thickness indicating that the film is highly resistive. On the basis of the high apparent film resistance it is proposed that the voltage dependence of the capacitance of the electrode interfaces arises from the ionization of deep level traps within the film and not from depletion layers associated with shallow donor or acceptor states. Application of voltages larger than about 2 endash 3 V results in the disappearance of the capacitance maxima indicating that irreversible changes in the electrode interfaces occur at higher electric fields. copyright 1995 American Institute of Physics

  16. In Situ High-Level Nitrogen Doping into Carbon Nanospheres and Boosting of Capacitive Charge Storage in Both Anode and Cathode for a High-Energy 4.5 V Full-Carbon Lithium-Ion Capacitor.

    Sun, Fei; Liu, Xiaoyan; Wu, Hao Bin; Wang, Lijie; Gao, Jihui; Li, Hexing; Lu, Yunfeng

    2018-05-02

    To circumvent the imbalances of electrochemical kinetics and capacity between Li + storage anodes and capacitive cathodes for lithium-ion capacitors (LICs), we herein demonstrate an efficient solution by boosting the capacitive charge-storage contributions of carbon electrodes to construct a high-performance LIC. Such a strategy is achieved by the in situ and high-level doping of nitrogen atoms into carbon nanospheres (ANCS), which increases the carbon defects and active sites, inducing more rapidly capacitive charge-storage contributions for both Li + storage anodes and PF 6 - storage cathodes. High-level nitrogen-doping-induced capacitive enhancement is successfully evidenced by the construction of a symmetric supercapacitor using commercial organic electrolytes. Coupling a pre-lithiated ANCS anode with a fresh ANCS cathode enables a full-carbon LIC with a high operating voltage of 4.5 V and high energy and power densities thereof. The assembled LIC device delivers high energy densities of 206.7 and 115.4 Wh kg -1 at power densities of 0.225 and 22.5 kW kg -1 , respectively, as well as an unprecedented high-power cycling stability with only 0.0013% capacitance decay per cycle within 10 000 cycles at a high power output of 9 kW kg -1 .

  17. PC operated acoustic transient spectroscopy of deep levels in MIS structures

    Bury, P.; Jamnicky, I.

    1996-01-01

    A new version of acoustic deep-level transient spectroscopy is presented to study the traps at the insulator-semiconductor interface. The acoustic deep-level transient spectroscopy uses an acoustoelectric response signal produced by the MIS structure interface when a longitudinal acoustic wave propagates through a structure. The acoustoelectric response signal is extremely sensitive to external conditions of the structure and reflects any changes in the charge distribution, connected also with charged traps. In comparison with previous version of acoustic deep-level transient spectroscopy that closely coincides with the principle of the original deep-level transient spectroscopy technique, the present technique is based on the computer-evaluated isothermal transients and represents an improved, more efficient and time saving technique. Many tests on the software used for calculation as well as on experimental setup have been performed. The improved acoustic deep-level transient spectroscopy method has been applied for the Si(p) MIS structures. The deep-level parameters as activation energy and capture cross-section have been determined. (authors)

  18. A deep level set method for image segmentation

    Tang, Min; Valipour, Sepehr; Zhang, Zichen Vincent; Cobzas, Dana; MartinJagersand

    2017-01-01

    This paper proposes a novel image segmentation approachthat integrates fully convolutional networks (FCNs) with a level setmodel. Compared with a FCN, the integrated method can incorporatesmoothing and prior information to achieve an accurate segmentation.Furthermore, different than using the level set model as a post-processingtool, we integrate it into the training phase to fine-tune the FCN. Thisallows the use of unlabeled data during training in a semi-supervisedsetting. Using two types o...

  19. Deep-level transient spectroscopy of TiO2/CuInS2 heterojunctions

    Nanu, M.; Boulch, F.; Schoonman, J.; Goossens, A.

    2005-01-01

    Deep-level transient spectroscopy (DLTS) has been used to measure the concentration and energy position of deep electronic states in CuInS2. Flat TiO2?CuInS2 heterojunctions as well as TiO2-CuInS2 nanocomposites have been investigated. Subband-gap electronic states in CuInS2 films are mostly due to

  20. MOS Capacitance—Voltage Characteristics III. Trapping Capacitance from 2-Charge-State Impurities

    Jie Binbin; Sah Chihtang

    2011-01-01

    Low-frequency and high-frequency capacitance—voltage curves of Metal—Oxide—Semiconductor Capacitors are presented to illustrate giant electron and hole trapping capacitances at many simultaneously present two-charge-state and one-trapped-carrier, or one-energy-level impurity species. Models described include a donor electron trap and an acceptor hole trap, both donors, both acceptors, both shallow energy levels, both deep, one shallow and one deep, and the identical donor and acceptor. Device and material parameters are selected to simulate chemically and physically realizable capacitors for fundamental trapping parameter characterizations and for electrical and optical signal processing applications. (invited papers)

  1. The Effects of Test Anxiety on Learning at Superficial and Deep Levels of Processing.

    Weinstein, Claire E.; And Others

    1982-01-01

    Using a deep-level processing strategy, low test-anxious college students performed significantly better than high test-anxious students in learning a paired-associate word list. Using a superficial-level processing strategy resulted in no significant difference in performance. A cognitive-attentional theory and test anxiety mechanisms are…

  2. Distinguishing bulk traps and interface states in deep-level transient spectroscopy

    Coelho, A V P; Adam, M C; Boudinov, H

    2011-01-01

    A new method for the distinction of discrete bulk deep levels and interface states related peaks in deep-level transient spectroscopy spectra is proposed. The measurement of two spectra using different reverse voltages while keeping pulse voltage fixed causes different peak maximum shifts in each case: for a reverse voltage modulus increase, a bulk deep-level related peak maximum will remain unchanged or shift towards lower temperatures while only interface states related peak maximum will be able to shift towards higher temperatures. This method has the advantage of being non-destructive and also works in the case of bulk traps with strong emission rate dependence on the electric field. Silicon MOS capacitors and proton implanted GaAs Schottky diodes were employed to experimentally test the method.

  3. Investigation of deep level defects in epitaxial semiconducting zinc sulpho-selenide. Progress report, 15 June 1979-14 June 1980

    Wessels, B.W.

    1980-01-01

    In an effort to understand the defect structure of the ternary II-VI compound zinc sulpho-selenide, the binary compound zinc selenide was investigated. Thin single crystalline films of zinc selenide were heteroepitaxially grown on (100) GaAs. Epitaxial layers from 5 to 50 microns thick could be readily grown using a chemical vapor transport technique. The layers had an excellent morphology with few stacking faults and hillocks. Detailed epitaxial growth kinetics were examined as a function of temperature and reactant concentration. It was found that hydrogen flow rate, source and substrate temperature affect the growth rate of the epitaxial films. Au - ZnSe Schottky barrier diodes and ZnSe - GaAs n-p heterojunctions were prepared from the epitaxial layers. Current-voltage characteristics were measured on both types of diodes. From capacitance-voltage measurements the residual doping density of the epitaxial layers were found to be of the order of 10 14 - 10 15 cm -3 . Finally, we have begun to measure the deep level spectrum of both the Schottky barrier diodes and the heterojunctions. Deep level transient spectroscopy appears to be well suited for determining trapping states in ZnSe provided the material has a low enough resistivity

  4. Impacts of Carrier Transport and Deep Level Defects on Delayed Cathodoluminescence in Droop-Mitigating InGaN/GaN LEDs

    Zhao, Zhibo; Singh, Akshay; Chesin, Jordan; Armitage, Rob; Wildeson, Isaac; Deb, Parijat; Armstrong, Andrew; Kisslinger, Kim; Stach, Eric; Gradecak, Silvija

    2017-07-25

    Prevalent droop mitigation strategies in InGaN-based LEDs require structural and/or compositional changes in the active region but are accompanied by a detrimental reduction in external quantum efficiency (EQE) due to increased Shockley-Read-Hall recombination. Understanding the optoelectronic impacts of structural modifications in InGaN/GaN quantum wells (QW) remains critical for emerging high-power LEDs. In this work, we use a combination of electron microscopy tools along with standard electrical characterization to investigate a wide range of low-droop InGaN/GaN QW designs. We find that chip-scale EQE is uncorrelated with extended well-width fluctuations observed in scanning transmission electron microscopy. Further, we observe delayed cathodoluminescence (CL) response from designs in which calculated band profiles suggest facile carrier escape from individual QWs. Samples with the slowest CL responses also exhibit the lowest EQEs and highest QW defect densities in deep level optical spectroscopy. We propose a model in which the electron beam (i) passivates deep level defect states and (ii) drives charge carrier accumulation and subsequent reduction of the built-in field across the multi-QW active region, resulting in delayed radiative recombination. Finally, we correlate CL rise dynamics with capacitance-voltage measurements and show that certain early-time components of the CL dynamics reflect the open circuit carrier population within one or more QWs.

  5. Deep geologic repository for low and intermediate radioactive level waste in Canada

    Liu Jianqin; Li Honghui; Sun Qinghong; Yang Zhongtian

    2012-01-01

    Ontario Power Generation (OPG) is undergoing a project for the long-term management of low and intermediate level waste (LILW)-a deep geologic repository (DGR) project for low and intermediate level waste. The waste source term disposed, geologic setting, repository layout and operation, and safety assessment are discussed. It is expected to provide reference for disposal of low and intermediate level waste that contain the higher concentration of long-lived radionuclides in China. (authors)

  6. Correlation of a generation-recombination center with a deep level trap in GaN

    Nguyen, X. S.; Lin, K.; Zhang, Z.; Arehart, A. R.; Ringel, S. A.; McSkimming, B.; Speck, J. S.; Fitzgerald, E. A.; Chua, S. J.

    2015-01-01

    We report on the identification of a deep level trap centre which contributes to generation-recombination noise. A n-GaN epilayer, grown by MOCVD on sapphire, was measured by deep level transient spectroscopy (DLTS) and noise spectroscopy. DLTS found 3 well documented deep levels at E c  − 0.26 eV, E c  − 0.59 eV, and E c  − 0.71 eV. The noise spectroscopy identified a generation recombination centre at E c  − 0.65 ± 0.1 eV with a recombination lifetime of 65 μs at 300 K. This level is considered to be the same as the one at E c  − 0.59 eV measured from DLTS, as they have similar trap densities and capture cross section. This result shows that some deep levels contribute to noise generation in GaN materials

  7. Deep levels in as-grown and electron-irradiated n-type GaN studied by deep level transient spectroscopy and minority carrier transient spectroscopy

    Duc, Tran Thien [Department of Physics, Chemistry and Biology (IFM), Linköping University, S-581 83 Linköping (Sweden); School of Engineering Physics, Hanoi University of Science and Technology, 1 Dai Co Viet Road, Hanoi (Viet Nam); Pozina, Galia; Son, Nguyen Tien; Kordina, Olof; Janzén, Erik; Hemmingsson, Carl [Department of Physics, Chemistry and Biology (IFM), Linköping University, S-581 83 Linköping (Sweden); Ohshima, Takeshi [Japan Atomic Energy Agency (JAEA), Takasaki, Gunma 370-1292 (Japan)

    2016-03-07

    Development of high performance GaN-based devices is strongly dependent on the possibility to control and understand defects in material. Important information about deep level defects is obtained by deep level transient spectroscopy and minority carrier transient spectroscopy on as-grown and electron irradiated n-type bulk GaN with low threading dislocation density produced by halide vapor phase epitaxy. One hole trap labelled H1 (E{sub V} + 0.34 eV) has been detected on as-grown GaN sample. After 2 MeV electron irradiation, the concentration of H1 increases and at fluences higher than 5 × 10{sup 14 }cm{sup −2}, a second hole trap labelled H2 is observed. Simultaneously, the concentration of two electron traps, labelled T1 (E{sub C} – 0.12 eV) and T2 (E{sub C} – 0.23 eV), increases. By studying the increase of the defect concentration versus electron irradiation fluence, the introduction rate of T1 and T2 using 2 MeV- electrons was determined to be 7 × 10{sup −3 }cm{sup −1} and 0.9 cm{sup −1}, respectively. Due to the low introduction rate of T1, it is suggested that the defect is associated with a complex. The high introduction rate of trap H1 and T2 suggests that the defects are associated with primary intrinsic defects or complexes. Some deep levels previously observed in irradiated GaN layers with higher threading dislocation densities are not detected in present investigation. It is therefore suggested that the absent traps may be related to primary defects segregated around dislocations.

  8. A study of ion implanted gallium arsenide using deep level transient spectroscopy

    Emerson, N.G.

    1981-03-01

    This thesis is concerned with the study of deep energy levels in ion implanted gallium arsenide (GaAs) using deep level transient spectroscopy (D.L.T.S.). The D.L.T.S. technique is used to characterise deep levels in terms of their activation energies and capture cross-sections and to determine their concentration profiles. The main objective is to characterise the effects on deep levels, of ion implantation and the related annealing processes. In the majority of cases assessment is carried out using Schottky barrier diodes. Low doses of selenium ions 1 to 3 x 10 12 cm -2 are implanted into vapour phase epitaxial (V.P.E.) GaAs and the effects of post-implantation thermal and pulsed laser annealing are compared. The process of oxygen implantation with doses in the range 1 x 10 12 to 5 x 10 13 cm -2 followed by thermal annealing at about 750 deg C, introduces a deep level at 0.79 eV from the conduction band. Oxygen implantation, at doses of 5 x 10 13 cm -2 , into V.P.E. GaAs produces a significant increase in the concentration of the A-centre (0.83 eV). High doses of zinc (10 15 cm -2 ) are implanted into n-type V.P.E. GaAs to form shallow p-type layers. The D.L.T.S. system described in the text is used to measure levels in the range 0.16 to 1.1 eV (for GaAs) with a sensitivity of the order 1:10 3 . (U.K.)

  9. Deep geologic storage of high level radioactive wastes: conceptual generic designs

    1995-01-01

    This report summarizes the studies on deep geologic storage of radioactive wastes and specially for the high-level radioactive wastes. The study is focussed to the geotechnical assessment and generic-conceptual designs. Methodology analysis, geotechnical feasibility, costs and operation are studied

  10. Iron and intrinsic deep level states in Ga2O3

    Ingebrigtsen, M. E.; Varley, J. B.; Kuznetsov, A. Yu.; Svensson, B. G.; Alfieri, G.; Mihaila, A.; Badstübner, U.; Vines, L.

    2018-01-01

    Using a combination of deep level transient spectroscopy, secondary ion mass spectrometry, proton irradiation, and hybrid functional calculations, we identify two similar deep levels that are associated with Fe impurities and intrinsic defects in bulk crystals and molecular beam epitaxy and hydride vapor phase epitaxi-grown epilayers of β-Ga2O3. First, our results indicate that FeGa, and not an intrinsic defect, acts as the deep acceptor responsible for the often dominating E2 level at ˜0.78 eV below the conduction band minimum. Second, by provoking additional intrinsic defect generation via proton irradiation, we identified the emergence of a new level, labeled as E2*, having the ionization energy very close to that of E2, but exhibiting an order of magnitude larger capture cross section. Importantly, the properties of E2* are found to be consistent with its intrinsic origin. As such, contradictory opinions of a long standing literature debate on either extrinsic or intrinsic origin of the deep acceptor in question converge accounting for possible contributions from E2 and E2* in different experimental conditions.

  11. A Closer Look at Deep Learning Neural Networks with Low-level Spectral Periodicity Features

    Sturm, Bob L.; Kereliuk, Corey; Pikrakis, Aggelos

    2014-01-01

    Systems built using deep learning neural networks trained on low-level spectral periodicity features (DeSPerF) reproduced the most “ground truth” of the systems submitted to the MIREX 2013 task, “Audio Latin Genre Classification.” To answer why this was the case, we take a closer look...

  12. Numerical investigation of high level nuclear waste disposal in deep anisotropic geologic repositories

    Salama, Amgad; El Amin, Mohamed F.; Sun, Shuyu

    2015-01-01

    One of the techniques that have been proposed to dispose high level nuclear waste (HLW) has been to bury them in deep geologic formations, which offer relatively enough space to accommodate the large volume of HLW accumulated over the years since

  13. Plan of deep underground construction for investigations on high-level radioactive waste storage

    Mayanovskij, M.S.

    1996-01-01

    The program of studies of the Japanese PNC corporation on construction of deep underground storage for high-level radioactive wastes is presented. The program is intended for 20 years. The total construction costs equal about 20 billion yen. The total cost of the project is equal to 60 billion yen. The underground part is planned to reach 1000 m depth

  14. Scanning deep level transient spectroscopy using an MeV ion microprobe

    Laird, J S; Bardos, R A; Saint, A; Moloney, G M; Legge, G F.J. [Melbourne Univ., Parkville, VIC (Australia)

    1994-12-31

    Traditionally the scanning ion microprobe has given little or no information regarding the electronic structure of materials in particular semiconductors. A new imaging technique called Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) is presented which is able to spatially map alterations in the band gap structure of materials by lattice defects or impurities. 3 refs., 2 figs.

  15. Deep-level transient spectroscopy of low-energy ion-irradiated silicon

    Kolkovsky, Vladimir; Privitera, V.; Nylandsted Larsen, Arne

    2009-01-01

     During electron-gun deposition of metal layers on semiconductors, the semiconductor is bombarded with low-energy metal ions creating defects in the outermost surface layer. For many years, it has been a puzzle why deep-level transient spectroscopy spectra of the as-deposited, electron-gun evapor...

  16. Scanning deep level transient spectroscopy using an MeV ion microprobe

    Laird, J.S.; Bardos, R.A.; Saint, A.; Moloney, G.M.; Legge, G.F.J. [Melbourne Univ., Parkville, VIC (Australia)

    1993-12-31

    Traditionally the scanning ion microprobe has given little or no information regarding the electronic structure of materials in particular semiconductors. A new imaging technique called Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) is presented which is able to spatially map alterations in the band gap structure of materials by lattice defects or impurities. 3 refs., 2 figs.

  17. Capacitive chemical sensor

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  18. Luminescence and deep-level transient spectroscopy of grown dislocation-rich Si layers

    I. I. Kurkina

    2012-09-01

    Full Text Available The charge deep-level transient spectroscopy (Q-DLTS is applied to the study of the dislocation-rich Si layers grown on a surface composed of dense arrays of Ge islands prepared on the oxidized Si surface. This provides revealing three deep-level bands located at EV + 0.31 eV, EC – 0.35 eV and EC – 0.43 eV using the stripe-shaped p-i-n diodes fabricated on the basis of these layers. The most interesting observation is the local state recharging process which proceeds with low activation energy (∼50 meV or without activation. The recharging may occur by carrier tunneling within deep-level bands owing to the high dislocation density ∼ 1011 - 1012 cm-2. This result is in favor of the suggestion on the presence of carrier transport between the deep states, which was previously derived from the excitation dependence of photoluminescence (PL intensity. Electroluminescence (EL spectra measured from the stripe edge of the same diodes contain two peaks centered near 1.32 and 1.55 μm. Comparison with PL spectra indicates that the EL peaks are generated from arsenic-contaminated and pure areas of the layers, respectively.

  19. Damage related deep electron levels in ion implanted GaAs

    Allsopp, D.W.E.; Peaker, A.R.

    1986-01-01

    A study has been made of the deep electron levels in semi-insulating GaAs implanted with either 78 Se + or 29 Si + ions and rendered n-type by subsequent annealing without encapsulation in partial pressures of arsenic or arsine. Three implantation related deep states were detected with concentration profiles approximating to the type of Gaussian distributions expected for point defects related to ion implantation damage. Further heat treatment of the samples at 500 0 C in a gas ambient of U 2 /H 2 substantially reduced concentration of these deep levels. Two of these states were thought to be related to displacements of the substrate atoms. The third, at Esubc -0.67 eV, was found in only 78 Se + ion implanted GaAs substrates and was thought to be a defect involving both Se and As atoms, rather than intrinsic lattice disorder. It is proposed that the annealing rate of these implantation related deep levels depends crucially on the in-diffusion of arsenic vacancies during heat treatments. (author)

  20. Point defects in gallium arsenide characterized by positron annihilation spectroscopy and deep level transient spectroscopy

    Mih, R.; Gronsky, R.; Sterne, P.A.

    1995-01-01

    Positron annihilation lifetime spectroscopy (PALS) is a unique technique for detection of vacancy related defects in both as-grown and irradiated materials. The authors present a systematic study of vacancy defects in stoichiometrically controlled p-type Gallium Arsenide grown by the Hot-Wall Czochralski method. Microstructural information based on PALS, was correlated to crystallographic data and electrical measurements. Vacancies were detected and compared to electrical levels detected by deep level transient spectroscopy and stoichiometry based on crystallographic data

  1. High levels of natural radionuclides in a deep-sea infaunal xenophyophore

    Swinbanks, D D; Shirayama, Y

    1986-03-27

    The paper concerns the high levels of natural radionuclides in a deep-sea infaunal xenophyophore from the Izu-Ogasawara Trench. Measured /sup 210/Po activities and barium contents of various parts of Occultammina profunda and the surrounding sediment are given, together with their estimated /sup 210/Pb and /sup 226/Ra activities. The data suggest that xenophyphores are probably subject to unusually high levels of natural radiation.

  2. Capacitive Feedthroughs for Medical Implants.

    Grob, Sven; Tass, Peter A; Hauptmann, Christian

    2016-01-01

    Important technological advances in the last decades paved the road to a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size, and increasing the number of included channels. Capacitive feedthroughs combine the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced demonstrators. The concept bears a high potential in improving current feedthrough technology, and could be applied on all kinds of electrical medical implants, even if its implementation might be challenging.

  3. Deep-level optical spectroscopy investigation of N-doped TiO2 films

    Nakano, Yoshitaka; Morikawa, Takeshi; Ohwaki, Takeshi; Taga, Yasunori

    2005-01-01

    N-doped TiO 2 films were deposited on n + -GaN/Al 2 O 3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 deg. C in flowing N 2 gas. The N-doping concentration was ∼8.8%, as determined from x-ray photoelectron spectroscopy measurements. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at ∼1.18 and ∼2.48 eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. Additionally, the 2.48 eV band is newly introduced by the N doping and contributes to band-gap narrowing by mixing with the O 2p valence band

  4. Lack of mutagens in deep-fat-fried foods obtained at the retail level.

    Taylor, S L; Berg, C M; Shoptaugh, N H; Scott, V N

    1982-04-01

    The basic methylene chloride extract from 20 of 30 samples of foods fried in deep fat failed to elicit any mutagenic response that could be detected in the Salmonella typhimurium/mammalian microsome assay. The basic extracts of the remaining ten samples (all three chicken samples studied, two of the four potato-chip samples, one of four corn-chip samples, the sample of onion rings, two of six doughnuts, and one of three samples of french-fried potato) showed evidence of weak mutagenic activity. In these samples, amounts of the basic extract equivalent to 28.5-57 g of the original food sample were required to produce revertants at levels of 2.6-4.8 times the background level. Only two of the acidic methylene chloride extracts from the 30 samples exhibited mutagenic activity greater than 2.5 times the background reversion level, and in both cases (one corn-chip and one shrimp sample) the mutagenic response was quite weak. The basic extract of hamburgers fried in deep fat in a home-style fryer possessed higher levels of mutagenic activity (13 times the background reversion level). However, the mutagenic activity of deep-fried hamburgers is some four times lower than that of pan-fried hamburgers.

  5. Reference design and operations for deep borehole disposal of high-level radioactive waste

    Herrick, Courtney Grant; Brady, Patrick Vane; Pye, Steven; Arnold, Bill Walter; Finger, John Travis; Bauer, Stephen J.

    2011-01-01

    A reference design and operational procedures for the disposal of high-level radioactive waste in deep boreholes have been developed and documented. The design and operations are feasible with currently available technology and meet existing safety and anticipated regulatory requirements. Objectives of the reference design include providing a baseline for more detailed technical analyses of system performance and serving as a basis for comparing design alternatives. Numerous factors suggest that deep borehole disposal of high-level radioactive waste is inherently safe. Several lines of evidence indicate that groundwater at depths of several kilometers in continental crystalline basement rocks has long residence times and low velocity. High salinity fluids have limited potential for vertical flow because of density stratification and prevent colloidal transport of radionuclides. Geochemically reducing conditions in the deep subsurface limit the solubility and enhance the retardation of key radionuclides. A non-technical advantage that the deep borehole concept may offer over a repository concept is that of facilitating incremental construction and loading at multiple perhaps regional locations. The disposal borehole would be drilled to a depth of 5,000 m using a telescoping design and would be logged and tested prior to waste emplacement. Waste canisters would be constructed of carbon steel, sealed by welds, and connected into canister strings with high-strength connections. Waste canister strings of about 200 m length would be emplaced in the lower 2,000 m of the fully cased borehole and be separated by bridge and cement plugs. Sealing of the upper part of the borehole would be done with a series of compacted bentonite seals, cement plugs, cement seals, cement plus crushed rock backfill, and bridge plugs. Elements of the reference design meet technical requirements defined in the study. Testing and operational safety assurance requirements are also defined. Overall

  6. Reference design and operations for deep borehole disposal of high-level radioactive waste.

    Herrick, Courtney Grant; Brady, Patrick Vane; Pye, Steven; Arnold, Bill Walter; Finger, John Travis; Bauer, Stephen J.

    2011-10-01

    A reference design and operational procedures for the disposal of high-level radioactive waste in deep boreholes have been developed and documented. The design and operations are feasible with currently available technology and meet existing safety and anticipated regulatory requirements. Objectives of the reference design include providing a baseline for more detailed technical analyses of system performance and serving as a basis for comparing design alternatives. Numerous factors suggest that deep borehole disposal of high-level radioactive waste is inherently safe. Several lines of evidence indicate that groundwater at depths of several kilometers in continental crystalline basement rocks has long residence times and low velocity. High salinity fluids have limited potential for vertical flow because of density stratification and prevent colloidal transport of radionuclides. Geochemically reducing conditions in the deep subsurface limit the solubility and enhance the retardation of key radionuclides. A non-technical advantage that the deep borehole concept may offer over a repository concept is that of facilitating incremental construction and loading at multiple perhaps regional locations. The disposal borehole would be drilled to a depth of 5,000 m using a telescoping design and would be logged and tested prior to waste emplacement. Waste canisters would be constructed of carbon steel, sealed by welds, and connected into canister strings with high-strength connections. Waste canister strings of about 200 m length would be emplaced in the lower 2,000 m of the fully cased borehole and be separated by bridge and cement plugs. Sealing of the upper part of the borehole would be done with a series of compacted bentonite seals, cement plugs, cement seals, cement plus crushed rock backfill, and bridge plugs. Elements of the reference design meet technical requirements defined in the study. Testing and operational safety assurance requirements are also defined. Overall

  7. Impact of deep levels on the electrical conductivity and luminescence of gallium nitride codoped with carbon and silicon

    Armstrong, A.; Arehart, A.R.; Green, D.; Mishra, U.K.; Speck, J.S.; Ringel, S.A.

    2005-01-01

    The impact of C incorporation on the deep level spectrum of n-type and semi-insulating GaN:C:Si films grown by rf plasma-assisted molecular-beam epitaxy (MBE) was investigated by the combination of deep level transient spectroscopy, steady-state photocapacitance, and transient deep level optical spectroscopy. The deep level spectra of the GaN:C:Si samples exhibited several band-gap states. A monotonic relation between systematic doping with C and quantitative trap concentration revealed C-related deep levels. A deep acceptor at E c -2.05 eV and a deep donor at E c -0.11 eV are newly reported states, and the latter is the first directly observed deep level attributed to the C Ga defect. A configuration-coordinate model involving localized lattice distortion revealed strong evidence that C-related deep levels at E c -3.0 eV and E ν +0.9 eV are likely identical and associated with the yellow luminescence in C-doped GaN films. Of the deep levels whose trap concentration increase with C doping, the band-gap states at E c -3.0 and 3.28 eV had the largest concentration, implying that free-carrier compensation by these deep levels is responsible for the semi-insulating behavior of GaN:C:Si films grown by MBE. The differing manner by which C incorporation in GaN may impact electrical conductivity in films grown by MBE and metal-organic chemical-vapor deposition is discussed

  8. Hydrogen effects on deep level defects in proton implanted Cu(In,Ga)Se{sub 2} based thin films

    Lee, D.W.; Seol, M.S.; Kwak, D.W.; Oh, J.S. [Department of Physics, Dongguk University, Seoul 100-715 (Korea, Republic of); Jeong, J.H. [Photo-electronic Hybrids Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Cho, H.Y., E-mail: hycho@dongguk.edu [Department of Physics, Dongguk University, Seoul 100-715 (Korea, Republic of)

    2012-08-01

    Hydrogen effects on deep level defects and a defect generation in proton implanted Cu(In,Ga)Se{sub 2} (CIGS) based thin films for solar cell were investigated. CIGS films with a thickness of 3 {mu}m were grown on a soda-lime glass substrate by a co-evaporation method, and then were implanted with protons. To study deep level defects in the proton implanted CIGS films, deep level transient spectroscopy measurements on the CIGS-based solar cells were carried out, these measurements found 6 traps (including 3 hole traps and 3 electron traps). In the proton implanted CIGS films, the deep level defects, which are attributed to the recombination centers of the CIGS solar cell, were significantly reduced in intensity, while a deep level defect was generated around 0.28 eV above the valence band maximum. Therefore, we suggest that most deep level defects in CIGS films can be controlled by hydrogen effects. - Highlights: Black-Right-Pointing-Pointer Proton implanted Cu(In,Ga)Se{sub 2} thin film and solar cell are prepared. Black-Right-Pointing-Pointer Deep level defects of Cu(In,Ga)Se{sub 2} thin film and solar cell are investigated. Black-Right-Pointing-Pointer Hydrogenation using proton implantation and H{sub 2} annealing reduces deep level defects. Black-Right-Pointing-Pointer Hydrogenation could enhance electrical properties and efficiency of solar cells.

  9. Radiation induced deep level defects in bipolar junction transistors under various bias conditions

    Liu, Chaoming; Yang, Jianqun; Li, Xingji; Ma, Guoliang; Xiao, Liyi; Bollmann, Joachim

    2015-01-01

    Bipolar junction transistor (BJT) is sensitive to ionization and displacement radiation effects in space. In this paper, 35 MeV Si ions were used as irradiation source to research the radiation damage on NPN and PNP bipolar transistors. The changing of electrical parameters of transistors was in situ measured with increasing irradiation fluence of 35 MeV Si ions. Using deep level transient spectroscopy (DLTS), defects in the bipolar junction transistors under various bias conditions are measured after irradiation. Based on the in situ electrical measurement and DLTS spectra, it is clearly that the bias conditions can affect the concentration of deep level defects, and the radiation damage induced by heavy ions.

  10. Albedo Neutron Dosimetry in a Deep Geological Disposal Repository for High-Level Nuclear Waste.

    Pang, Bo; Becker, Frank

    2017-04-28

    Albedo neutron dosemeter is the German official personal neutron dosemeter in mixed radiation fields where neutrons contribute to personal dose. In deep geological repositories for high-level nuclear waste, where neutrons can dominate the radiation field, it is of interest to investigate the performance of albedo neutron dosemeter in such facilities. In this study, the deep geological repository is represented by a shielding cask loaded with spent nuclear fuel placed inside a rock salt emplacement drift. Due to the backscattering of neutrons in the drift, issues concerning calibration of the dosemeter arise. Field-specific calibration of the albedo neutron dosemeter was hence performed with Monte Carlo simulations. In order to assess the applicability of the albedo neutron dosemeter in a deep geological repository over a long time scale, spent nuclear fuel with different ages of 50, 100 and 500 years were investigated. It was found out, that the neutron radiation field in a deep geological repository can be assigned to the application area 'N1' of the albedo neutron dosemeter, which is typical in reactors and accelerators with heavy shielding. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Electrical and optical deep level spectroscopy on Os doped p-InP

    Parveen, S.; Zafar, N.; Khan, A.; Qureshi, U.S.; Iqbal, M.Z.

    1997-01-01

    Transition metal (TM) impurities are introduced for obtaining semi insulating (III-V) compound semiconductors used as base material for electronic and optoelectronic devices. TM doping introduces near mid gap levels which are used to compensate shallow level donors and acceptors in (III-V) compound semiconductors. The study of electrical properties of heavier transition metals in InP has been turned to an active field of research owing to their potential to produce thermally stable semi insulating substrate materials. Osmium has been tried for this purpose in our work. InP: Os samples have been grown by low pressure metalorganic chemical vapour deposition (LP-MOCVD). Optical and electrical Deep Level Transient Spectroscopy Techniques have been used to characterise osmium related deep level defects in the p-type samples. Three majority carrier (Hole) emitting levels OsA, OsB, OsC and one minority carrier (electron) emitting level Osl are observed in the DLTS and ODLTS measurements on p-type InP:Os. ON optical injection, only Osl appears and all other majority carrier emitting levels disappear dramatically. Special emphasis is given to the detailed comparison by ODLTS and EDLTS, which yields important information on the relative capture cross-sections of Osmium induced levels in p-InP. (author)

  12. Comparison of the nonradiative deep levels in silicon solar cells made of monocrystalline, polycrystalline and amorphous silicon using deep level transient spectroscopy (DLTS)

    Hammadeh, H.; Darwich, R.

    2005-03-01

    The aim of this work is to study the defects in solar cells fabricated from crystalline, polycrystalline and amorphous silicon. Using Deep Level Transient Spectroscopy technique, (DLTS), we have determined their activation energies, concentrations and their effect on the solar cell efficiency. Our results show a DLTS peak in crystalline silicon which we could attribute to tow peaks originating from iron contamination. In the polycrystalline based solar cells we observed a series of non conventional DLTS peaks while in amorphous silicon we observed a peak using low measurement frequencies (between 8 kHz and 20 kHz). We studied these defects and determined their activation energies as well as the capture cross section for one of them. We suggest a possible configuration of these defects. We cannot able to study the effect of these defects on the solar cell efficiency because we have not the experimental set-up which measure the solar cell efficiency. (Authors)

  13. Effects of heat from high-level waste on performance of deep geological repository components

    1984-11-01

    This report discusses the effects of heat on the deep geological repository systems and its different components. The report is focussed specifically on effects due to thermal energy release solely from high-level waste or spent fuel. It reviews the experimental data and theoretical models of the effects of heat both on the behaviour of engineered and natural barriers. A summary of the current status of research and repository development including underground test facilities is presented

  14. Identification of deep levels in GaN associated with dislocations

    Soh, C B; Chua, S J; Lim, H F; Chi, D Z; Liu, W; Tripathy, S

    2004-01-01

    To establish a correlation between dislocations and deep levels in GaN, a deep-level transient spectroscopy study has been carried out on GaN samples grown by metalorganic chemical vapour deposition. In addition to typical undoped and Si-doped GaN samples, high-quality crack-free undoped GaN film grown intentionally on heavily doped cracked Si-doped GaN and cracked AlGaN templates are also chosen for this study. The purpose of growth of such continuous GaN layers on top of the cracked templates is to reduce the screw dislocation density by an order of magnitude. Deep levels in these layers have been characterized and compared with emphasis on their thermal stabilities and capture kinetics. Three electron traps at E c -E T ∼0.10-0.11, 0.24-0.27 and 0.59-0.63 eV are detected common to all the samples while additional levels at E c -E T ∼0.18 and 0.37-0.40 eV are also observed in the Si-doped GaN. The trap levels exhibit considerably different stabilities under rapid thermal annealing. Based on the observations, the trap levels at E c -E T ∼0.18 and 0.24-0.27 eV can be associated with screw dislocations, whereas the level at E c -E T ∼0.59-0.63 eV can be associated with edge dislocations. This is also in agreement with the transmission electron microscopy measurements conducted on the GaN samples

  15. DLTS study of annihilation of oxidation induced deep-level defects ...

    Administrator

    microelectronics device technologies. As technology is ... an important role in manufacturing high-speed electronic ... DLTS is a capacitance transient thermal scanning tech- ... again dipped in methanol and dried using nitrogen gun. A.

  16. Multi-level gene/MiRNA feature selection using deep belief nets and active learning.

    Ibrahim, Rania; Yousri, Noha A; Ismail, Mohamed A; El-Makky, Nagwa M

    2014-01-01

    Selecting the most discriminative genes/miRNAs has been raised as an important task in bioinformatics to enhance disease classifiers and to mitigate the dimensionality curse problem. Original feature selection methods choose genes/miRNAs based on their individual features regardless of how they perform together. Considering group features instead of individual ones provides a better view for selecting the most informative genes/miRNAs. Recently, deep learning has proven its ability in representing the data in multiple levels of abstraction, allowing for better discrimination between different classes. However, the idea of using deep learning for feature selection is not widely used in the bioinformatics field yet. In this paper, a novel multi-level feature selection approach named MLFS is proposed for selecting genes/miRNAs based on expression profiles. The approach is based on both deep and active learning. Moreover, an extension to use the technique for miRNAs is presented by considering the biological relation between miRNAs and genes. Experimental results show that the approach was able to outperform classical feature selection methods in hepatocellular carcinoma (HCC) by 9%, lung cancer by 6% and breast cancer by around 10% in F1-measure. Results also show the enhancement in F1-measure of our approach over recently related work in [1] and [2].

  17. Large lattice relaxation deep levels in neutron-irradiated GaN

    Li, S.; Zhang, J.D.; Beling, C.D.; Wang, K.; Wang, R.X.; Gong, M.; Sarkar, C.K.

    2005-01-01

    Deep level transient spectroscopy (DLTS) and deep level optical spectroscopy (DLOS) measurements have been carried out in neutron-irradiated n-type hydride-vapor-phase-epitaxy-grown GaN. A defect center characterized by a DLTS line, labeled as N1, is observed at E C -E T =0.17 eV. Another line, labeled as N2, at E C -E T =0.23 eV, seems to be induced at the same rate as N1 under irradiation and may be identified with E1. Other defects native to wurtzite GaN such as the C and E2 lines appear to enhance under neutron irradiation. The DLOS results show that the defects N1 and N2 have large Frank-Condon shifts of 0.64 and 0.67 eV, respectively, and hence large lattice relaxations. The as-grown and neutron-irradiated samples all exhibit the persistent photoconductivity effect commonly seen in GaN that may be attributed to DX centers. The concentration of the DX centers increases significantly with neutron dosage and is helpful in sustaining sample conductivity at low temperatures, thus making possible DLTS measurements on N1 an N2 in the radiation-induced deep-donor defect compensated material which otherwise are prevented by carrier freeze-out

  18. Membrane capacitive deionization

    Biesheuvel, P.M.; Wal, van der A.

    2010-01-01

    Membrane capacitive deionization (MCDI) is an ion-removal process based on applying an electrical potential difference across an aqueous solution which flows in between oppositely placed porous electrodes, in front of which ion-exchange membranes are positioned. Due to the applied potential, ions

  19. Capacitance for carbon capture

    Landskron, Kai

    2018-01-01

    Metal recycling: A sustainable, capacitance-assisted carbon capture and sequestration method (Supercapacitive Swing Adsorption) can turn scrap metal and CO 2 into metal carbonates at an attractive energy cost. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Capacitance for carbon capture

    Landskron, Kai [Department of Chemistry, Lehigh University, Bethlehem, PA (United States)

    2018-03-26

    Metal recycling: A sustainable, capacitance-assisted carbon capture and sequestration method (Supercapacitive Swing Adsorption) can turn scrap metal and CO{sub 2} into metal carbonates at an attractive energy cost. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. The study of the deep levels of In/CdTe Schottky diode

    Kim, Hey-kyeong; Jeen, Gwangsoo; Nam, S.H.

    2000-01-01

    p-type CdTe is an important component of II-VI compound based solar cells as well as a promising substance for X- and gamma-ray detector. Despite that a lot of researches has been performed on CdTe, the manufacture of large homogeneous ingots with high resistivity (ρ) and a high value of lifetime-mobility product (μτ) still difficult. Both ρ and μτ, which determine detection properties, are strongly dependent on the impurity and defect levels of crystals. As in general, deep defect levels act as recombination centers and influence strongly the efficiency of the detector material, so information about deep levels is an essential need. To estimate deep levels of semiconductor materials, the TSC (thermally stimulated current), TSCD (thermally stimulated capacitor discharges) and admittance spectroscopic method are used. In order to study the deep levels of CdTe, the samples were taken from a CdTe-crystal grown by the vertical Bridgman method. From this boule single crystalline samples of about 0.5 mm thickness were prepared. All samples were initially p-type which was determined by the hot-probe method. In-CdTe Schottky diodes were prepared by the process of evaporation of In in the vacuum of 10 -6 Torr on surface of CdTe. The area of the deposited contact was equal to 1.626 mm 2 . As ohmic contacts, dots of Au soldered for 30 min. in temperature 160 deg C. Measurements were carried out within a 100-250 K temperature and 1-10 kHz frequency range. Related Arrhenius plots, i.e. the experimentally determined emission rates corresponding to the signal maximum divided by the square of temperature as a function of reciprocal temperature are plotted. The experimental data were best fitted by the least-square method. The fitting yielded the defect level energies E T . In this study, by using admittance spectroscopy measurements, we presented the information about the energy and concentration of the defect levels inside the gap, in order to improve the quality of

  2. Theory of deep level trap effects on generation-recombination noise in HgCdTe photoconductors

    Iverson, A.E.; Smith, D.L.

    1985-01-01

    We present a theory of the effect of deep level centers on the generation-recombination (g-r) noise and responsivity of an intrinsic photoconductor. The deep level centers can influence the g-r noise and responsivity in three main ways: (i) they can shorten the bulk carrier lifetime by Shockley--Read--Hall recombination; (ii) for some values of the capture cross sections, deep level densities, and temperature, the deep levels can trap a significant fraction of the photogenerated minority carriers. This trapping reduces the effective minority carrier mobility and diffusivity and thus reduces the effect of carrier sweep out on both g-r noise and responsivity; (iii) the deep level centers add a new thermal noise source, which results from fluctuations between bound and free carriers. The strength of this new noise source decreases with decreasing temperature at a slower rate than band-to-band thermal g-r noise. Calculations have been performed for a X = 0.21, n-type Hg/sub 1-x/Cd/sub x/Te photoconductor using the parameters of a commonly occurring deep level center in this material. We find that for typical operating conditions photoconductive detector performance begins to degrade as the deep level density begins to exceed 10 16 cm -3

  3. Spectroscopy of deep doping levels in Cd0.99Mn0.01Te:Ga

    Szatkowski, J.; Placzek-Popko, E.; Sieranski, K.; Bieg, B.

    1997-01-01

    The investigation results of deep energy levels in Cd 0.99 Mn 0.01 Te (n-type) doped with gallium have been presented. Deep level transient spectroscopy (DLTS) measurements have been carried out in temperature range 80-420 K. The results show five types of electron traps. The activation energy of trapping levels and electron trapping cross-sections have been determined for observed traps. 2 refs, 3 figs, 1 tab

  4. Investigation of electrically-active deep levels in single-crystalline diamond by particle-induced charge transient spectroscopy

    Kada, W., E-mail: kada.wataru@gunma-u.ac.jp [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kambayashi, Y.; Ando, Y. [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Onoda, S. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Umezawa, H.; Mokuno, Y. [National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Shikata, S. [Kwansei Gakuin Univ., 2-1, Gakuen, Mita, Hyogo 669-1337 (Japan); Makino, T.; Koka, M. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Hanaizumi, O. [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kamiya, T.; Ohshima, T. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan)

    2016-04-01

    To investigate electrically-active deep levels in high-resistivity single-crystalline diamond, particle-induced charge transient spectroscopy (QTS) techniques were performed using 5.5 MeV alpha particles and 9 MeV carbon focused microprobes. For unintentionally-doped (UID) chemical vapor deposition (CVD) diamond, deep levels with activation energies of 0.35 eV and 0.43 eV were detected which correspond to the activation energy of boron acceptors in diamond. The results suggested that alpha particle and heavy ion induced QTS techniques are the promising candidate for in-situ investigation of deep levels in high-resistivity semiconductors.

  5. Spectroscopy of Deep Traps in Cu2S-CdS Junction Structures

    Eugenijus Gaubas

    2012-12-01

    Full Text Available Cu2S-CdS junctions of the polycrystalline material layers have been examined by combining the capacitance deep level transient spectroscopy technique together with white LED light additional illumination (C-DLTS-WL and the photo-ionization spectroscopy (PIS implemented by the photocurrent probing. Three types of junction structures, separated by using the barrier capacitance characteristics of the junctions and correlated with XRD distinguished precipitates of the polycrystalline layers, exhibit different deep trap spectra within CdS substrates.

  6. Radon 222 levels in deep well waters of Toluca municipality (county)

    Olguin Gutierrez, Maria Teresa.

    1990-01-01

    The levels of Radon 222 were determined in 46 deep (50-180m) wells in the city and county of Toluca, as well as the annual radiation dose that the stomach admits when ingesting such water. The method used for the quantification of Radon 222 was liquid scintillation counting. The result revealed that levels of Radon 222 in the studied area in the range of 0 to 320 pCi l -1 . In the case of the equivalent annual dose that the stomach (empty) admits due to ingestion of water from the wells, values are in an interval between 0 to 95 mrem a -1 . This values are well below the level established by the International Commission of Radiological Protection (ICRP). The wells that had the higher concentration of Radon 222 were found in the regions of Lodo Prieto, Seminario; San Antonio Buenavista and La Trinidad Huichochitlan. (Author)

  7. Irradiation induced defects containing oxygen atoms in germanium crystal as studied by deep level transient spectroscopy

    Fukuoka, Noboru; Kambe, Yoshiyuki; Saito, Haruo; Matsuda, Koji.

    1984-05-01

    Deep level transient spectroscopy was applied to the electron trapping levels which are associated with the irradiation induced lattice defects in germanium crystals. The germanium crystals used in the study were doped with oxygen, antimony or arsenic and the defects were formed by electron irradiation of 1.5MeV or 10MeV. The nature of so called ''thermal defect'' formed by heat treatment at about 670K was also studied. The trapping levels at Esub(c)-0.13eV, Esub(c)-0.25eV and Esub(c)-0.29eV were found to be associated with defects containing oxygen atoms. From the experimental results the Esub(c)-0.25eV level was attributed to the germanium A-center (interstitial oxygen atom-vacancy pair). Another defect associated with the 715cm -1 infrared absorption band was found to have a trapping level at the same position at Esub(c)-0.25eV. The Esub(c)-0.23eV and Esub(c)-0.1eV levels were revealed to be associated with thermal donors formed by heat treatment at about 670K. Additional two peaks (levels) were observed in the DLTS spectrum. The annealing behavior of the levels suggests that the thermal donors originate from not a single type but several types of defects. (author)

  8. Deep level centers in electron-irradiated silicon crystals doped with copper at different temperatures

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

    2017-07-15

    The effect of bombardment with energetic particles on the deep-level spectrum of copper-contaminated silicon wafers is studied by space charge spectroscopy methods. The p-type FZ-Si wafers were doped with copper in the temperature range of 645-750 C and then irradiated with the 10{sup 15} cm{sup -2} fluence of 5 MeV electrons at room temperature. Only the mobile Cu{sub i} species and the Cu{sub PL} centers are detected in significant concentrations in the non-irradiated Cu-doped wafers. The properties of the irradiated samples are found to qualitatively depend on the copper in-diffusion temperature T{sub diff}. For T{sub diff} > 700 C, the irradiation partially reduces the Cu{sub i} concentration and introduces additional Cu{sub PL} centers while no standard radiation defects are detected. If T{sub diff} was below ∝700 C, the irradiation totally removes the mobile Cu{sub i} species. Instead, the standard radiation defects and their complexes with copper appear in the deep-level spectrum. A model for the defects reaction scheme during the irradiation is derived and discussed. DLTS spectrum of the Cu-contaminated and then irradiated silicon qualitatively depends on the copper in-diffusion temperature. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Deep level transient spectroscopic investigation of phosphorus-doped silicon by self-assembled molecular monolayers.

    Gao, Xuejiao; Guan, Bin; Mesli, Abdelmadjid; Chen, Kaixiang; Dan, Yaping

    2018-01-09

    It is known that self-assembled molecular monolayer doping technique has the advantages of forming ultra-shallow junctions and introducing minimal defects in semiconductors. In this paper, we report however the formation of carbon-related defects in the molecular monolayer-doped silicon as detected by deep-level transient spectroscopy and low-temperature Hall measurements. The molecular monolayer doping process is performed by modifying silicon substrate with phosphorus-containing molecules and annealing at high temperature. The subsequent rapid thermal annealing drives phosphorus dopants along with carbon contaminants into the silicon substrate, resulting in a dramatic decrease of sheet resistance for the intrinsic silicon substrate. Low-temperature Hall measurements and secondary ion mass spectrometry indicate that phosphorus is the only electrically active dopant after the molecular monolayer doping. However, during this process, at least 20% of the phosphorus dopants are electrically deactivated. The deep-level transient spectroscopy shows that carbon-related defects are responsible for such deactivation.

  10. Automatic recognition of severity level for diagnosis of diabetic retinopathy using deep visual features.

    Abbas, Qaisar; Fondon, Irene; Sarmiento, Auxiliadora; Jiménez, Soledad; Alemany, Pedro

    2017-11-01

    Diabetic retinopathy (DR) is leading cause of blindness among diabetic patients. Recognition of severity level is required by ophthalmologists to early detect and diagnose the DR. However, it is a challenging task for both medical experts and computer-aided diagnosis systems due to requiring extensive domain expert knowledge. In this article, a novel automatic recognition system for the five severity level of diabetic retinopathy (SLDR) is developed without performing any pre- and post-processing steps on retinal fundus images through learning of deep visual features (DVFs). These DVF features are extracted from each image by using color dense in scale-invariant and gradient location-orientation histogram techniques. To learn these DVF features, a semi-supervised multilayer deep-learning algorithm is utilized along with a new compressed layer and fine-tuning steps. This SLDR system was evaluated and compared with state-of-the-art techniques using the measures of sensitivity (SE), specificity (SP) and area under the receiving operating curves (AUC). On 750 fundus images (150 per category), the SE of 92.18%, SP of 94.50% and AUC of 0.924 values were obtained on average. These results demonstrate that the SLDR system is appropriate for early detection of DR and provide an effective treatment for prediction type of diabetes.

  11. Sea-level and deep-sea-temperature variability over the past 5.3 million years.

    Rohling, E J; Foster, G L; Grant, K M; Marino, G; Roberts, A P; Tamisiea, M E; Williams, F

    2014-04-24

    Ice volume (and hence sea level) and deep-sea temperature are key measures of global climate change. Sea level has been documented using several independent methods over the past 0.5 million years (Myr). Older periods, however, lack such independent validation; all existing records are related to deep-sea oxygen isotope (δ(18)O) data that are influenced by processes unrelated to sea level. For deep-sea temperature, only one continuous high-resolution (Mg/Ca-based) record exists, with related sea-level estimates, spanning the past 1.5 Myr. Here we present a novel sea-level reconstruction, with associated estimates of deep-sea temperature, which independently validates the previous 0-1.5 Myr reconstruction and extends it back to 5.3 Myr ago. We find that deep-sea temperature and sea level generally decreased through time, but distinctly out of synchrony, which is remarkable given the importance of ice-albedo feedbacks on the radiative forcing of climate. In particular, we observe a large temporal offset during the onset of Plio-Pleistocene ice ages, between a marked cooling step at 2.73 Myr ago and the first major glaciation at 2.15 Myr ago. Last, we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep-sea temperature.

  12. Constraints on sea level during the Pliocene: Records from the deep Pacific Ocean

    Woodard, S. C.; Rosenthal, Y.; Miller, K. G.; Wright, J. D.; Chiu, B. K.

    2013-12-01

    To reconstruct sea level during the transition from peak late Pliocene warmth (~3.15 Ma) to the onset of N. Hemisphere glaciation (~2.75 Ma), we generated high resolution stable isotope (δ18O, δ13C) and trace metal (Mg/Ca) records using benthic foraminifera, Uvigerina sp., from northwest Pacific ODP Site 1208 (3350 m water depth). During the peak late Pliocene warmth Mg/Ca-derived temperature records indicate deep Pacific interglacial temperatures were not significantly warmer (+0.6 ×0.8°C) than modern and glacial temperatures were near freezing similar to the LGM. In contrast, the deep N. Atlantic (Site 607) was apparently ~3°C warmer than the modern during both Pliocene glacial and interglacial periods (Sosdian and Rosenthal, 2009), based on the Mg/Ca of P. wuellerstorfi, which may be influenced by carbonate ion effect (Elderfield et al., 2009 and refs therein). δ18O records indicate a significant long-term increase in benthic δ18O in both the N. Atlantic and N. Pacific, although the rate of increase (Δδ18O) in the N. Atlantic is approximately 3x that of the N. Pacific (Site 1208), based on least squares regressions of all glacial-interglacial data. The discrepancy in the Δδ18O between the two basins is explained by Mg/Ca-derived temperature records. Results from Site 1208 show that the deep Pacific experienced no long-term cooling over the period 3.15-2.7 Ma when the deep N. Atlantic cooled by ~2.5°C on average. The relatively stable Pacific deep-water record provides the more reliable reconstructions of sea-level changes. From 3.15-2.7 Ma, Pacific δ18O data records an average increase of ~0.19× 0.08 per mil implying a sea level drop of 19 m × 8 m. After correcting the N. Atlantic record for temperature, we find the long term δ18O change from 3.15-2.7 Ma is ~0.23×0.1 per mil which equates to a peak of 23 m × 10 m. Our estimates are further corroborated by foraminiferal calcite δ18O recorded during Pliocene peak interglacials KM3 and G17. The

  13. Localized deep levels in AlxGa1−xN epitaxial films with various Al compositions

    Shi Li-Yang; Shen Bo; Wang Ping; Yan Jian-Chang; Wang Jun-Xi

    2014-01-01

    By using high-temperature deep-level transient spectroscopy (HT-DLTS) and other electrical measurement techniques, localized deep levels in n-type Al x Ga 1−x N epitaxial films with various Al compositions (x = 0, 0.14, 0.24, 0.33, and 0.43) have been investigated. It is found that there are three distinct deep levels in Al x Ga 1−x N films, whose level position with respect to the conduction band increases as Al composition increases. The dominant defect level with the activation energy deeper than 1.0 eV below the conduction band closely follows the Fermi level stabilization energy, indicating that its origin may be related to the defect complex, including the anti-site defects and divacancies in Al x Ga 1−x N films. (condensed matter: structural, mechanical, and thermal properties)

  14. Capacitance-voltage characteristics of GaAs ion-implanted structures

    Privalov E. N.

    2008-08-01

    Full Text Available A noniterative numerical method is proposed to calculate the barrier capacitance of GaAs ion-implanted structures as a function of the Schottky barrier bias. The features of the low- and high-frequency capacitance-voltage characteristics of these structures which are due to the presence of deep traps are elucidated.

  15. Should the U.S. proceed to consider licensing deep geological disposal of high-level nuclear waste

    Curtiss, J.R.

    1993-01-01

    The United States, as well as other countries facing the question of how to handle high-level nuclear waste, has decided that the most appropriate means of disposal is in a deep geologic repository. In recent years, the Radioactive Waste Management Committee of the Nuclear Energy Agency has developed several position papers on the technical achievability of deep geologic disposal, thus demonstrating the serious consideration of deep geologic disposal in the international community. The Committee has not, as yet, formally endorsed disposal in a deep geologic repository as the preferred method of handling high-level nuclear waste. The United States, on the other hand, has studied the various methods of disposing of high-level nuclear waste, and has determined that deep geologic disposal is the method that should be developed. The purpose of this paper is to present a review of the United States' decision on selecting deep geologic disposal as the preferred method of addressing the high-level waste problem. It presents a short history of the steps taken by the U.S. in determining what method to use, discusses the NRC's waste Confidence Decision, and provides information on other issues in the U.S. program such as reconsideration of the final disposal standard and the growing inventory of spent fuel in storage

  16. Capacitive discharge exciplex lamps

    Sosnin, E A; Erofeev, M V; Tarasenko, V F [High Current Electronics Institute, 2/3, Akademichesky Ave., Tomsk 634055 (Russian Federation)

    2005-09-07

    Simple-geometry exciplex lamps of a novel type excited by a capacitive discharge (CD-excilamps) have been investigated. An efficient radiation has been obtained on KrBr*, KrCl*, XeBr*, XeCl* molecules and I* atom. The highest values of efficiency of various working molecules are approximately 10-18%. The lifetime of the operating gas mixture in KrCl*, XeCl*, I* and XeBr* exciplex lamps excited by a CD is above 1000 h. Owing to the above-mentioned characteristics, the exciplex lamps excited by a CD are supposed to be very promising for various applications.

  17. Capacitive discharge exciplex lamps

    Sosnin, E A; Erofeev, M V; Tarasenko, V F

    2005-01-01

    Simple-geometry exciplex lamps of a novel type excited by a capacitive discharge (CD-excilamps) have been investigated. An efficient radiation has been obtained on KrBr*, KrCl*, XeBr*, XeCl* molecules and I* atom. The highest values of efficiency of various working molecules are approximately 10-18%. The lifetime of the operating gas mixture in KrCl*, XeCl*, I* and XeBr* exciplex lamps excited by a CD is above 1000 h. Owing to the above-mentioned characteristics, the exciplex lamps excited by a CD are supposed to be very promising for various applications

  18. TECHNICAL AND ECONOMIC EVALUATION OF OPTIMAL VOLTAGE LEVEL FOR THE POWER SUPPLY OF DEEP MINE OPERATING HORIZONS

    Shkrabets, F. P.; Ostapchuk, O. V.; Kozhevnikov, A. V.; Akulov, A. V.

    2015-01-01

    The most perspective option for possible deep mine power supply is the one with the deep input of 35 kV voltage by installing of underground 35kV/6 kV substation. This option is caused by the expected level of electrical loads, provided by mine development, the power consumers’ deep layout (considering the distance from the source to the shaft on the surface and from the shaft to the underground substation chamber) and primary and the most responsible power consumers (blind shaft lifting devi...

  19. Influence of growth temperature and temperature ramps on deep level defect incorporation in m-plane GaN

    Armstrong, A. M.; Kelchner, K.; Nakamura, S.; DenBaars, S. P.; Speck, J. S.

    2013-01-01

    The dependence of deep level defect incorporation in m-plane GaN films grown by metal-organic chemical vapor deposition on bulk m-plane GaN substrates as a function of growth temperature (T g ) and T g ramping method was investigated using deep level optical spectroscopy. Understanding the influence of T g on GaN deep level incorporation is important for InGaN/GaN multi-quantum well (MQW) light emitting diodes (LEDs) and laser diodes (LDs) because GaN quantum barrier (QB) layers are grown much colder than thin film GaN to accommodate InGaN QW growth. Deep level spectra of low T g (800 °C) GaN films grown under QB conditions were compared to deep level spectra of high T g (1150 °C) GaN. Reducing T g , increased the defect density significantly (>50×) through introduction of emergent deep level defects at 2.09 eV and 2.9 eV below the conduction band minimum. However, optimizing growth conditions during the temperature ramp when transitioning from high to low T g substantially reduced the density of these emergent deep levels by approximately 40%. The results suggest that it is important to consider the potential for non-radiative recombination in QBs of LED or LD active regions, and tailoring the transition from high T g GaN growth to active layer growth can mitigate such non-radiative channels

  20. Extended deep level defects in Ge-condensed SiGe-on-Insulator structures fabricated using proton and helium implantations

    Kwak, D.W.; Lee, D.W.; Oh, J.S.; Lee, Y.H.; Cho, H.Y.

    2012-01-01

    SiGe-on-Insulator (SGOI) structures were created using the Ge condensation method, where an oxidation process is performed on the SiGe/Si structure. This method involves rapid thermal chemical vapor deposition and H + /He + ion-implantations. Deep level defects in these structures were investigated using deep level transient spectroscopy (DLTS) by varying the pulse injection time. According to the DLTS measurements, a deep level defect induced during the Ge condensation process was found at 0.28 eV above the valence band with a capture cross section of 2.67 × 10 −17 cm 2 , two extended deep levels were also found at 0.54 eV and 0.42 eV above the valence band with capture cross sections of 3.17 × 10 −14 cm 2 and 0.96 × 10 −15 cm 2 , respectively. In the SGOI samples with ion-implantation, the densities of the newly generated defects as well as the existing defects were decreased effectively. Furthermore, the Coulomb barrier heights of the extended deep level defects were drastically reduced. Thus, we suggest that the Ge condensation method with H + ion implantation could reduce deep level defects generated from the condensation and control the electrical properties of the condensed SiGe layers. - Highlights: ► We have fabricated low-defective SiGe-on-Insulator (SGOI) with implantation method. ► H + and He + -ions are used for ion-implantation method. ► We have investigated the deep level defects of SGOI layers. ► Ge condensation method using H + ion implantation could reduce extended defects. ► They could enhance electrical properties.

  1. Capacitance of circular patch resonator

    Miano, G.; Verolino, L.; Naples Univ.; Panariello, G.; Vaccaro, V.G.; Naples Univ.

    1995-11-01

    In this paper the capacitance of the circular microstrip patch resonator is computed. It is shown that the electrostatic problem can be formulated as a system of dual integral equations, and the most interesting techniques of solutions of these systems are reviewed. Some useful approximated formulas for the capacitance are derived and plots of the capacitance are finally given in a wide range of dielectric constants

  2. Electrochemical capacitance performance of titanium nitride nanoarray

    Xie, Yibing, E-mail: ybxie@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Suzhou Research Institute of Southeast University, Suzhou 215123 (China); Wang, Yong [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Du, Hongxiu [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Suzhou Research Institute of Southeast University, Suzhou 215123 (China)

    2013-12-01

    Highlights: • TiN nanoarray is formed by a nitridation process of TiO{sub 2} in ammonia atmosphere. • TiN nanoarray exhibits much higher EDLC capacitance than TiO{sub 2} nanoarray. • The specific capacitance of TiN nanoarray achieves a high level of 99.7 mF cm{sup −2}. • A flexible solid-state supercapacitor is constructed by TiN nanoarray and PVA gel. -- Abstract: In this study, titanium nitride (TiN) nanoarrays with a short nanotube and long nanopore structure have been prepared by an anodization process of ultra thin titanium foil in ethylene glycol (EG) solution containing ammonium fluoride, subsequent calcination process in an air atmosphere, and final nitridation process in an ammonia atmosphere. The morphology and microstructure characterization has been conducted using field emission scanning electron microscope and X-ray diffraction. The electrochemical properties have been investigated through cyclic voltammetry and electrochemical impedance spectrum measurements. The electrochemical capacitance performance has been investigated by galvanostatic charge–discharge measurements in the acidic, neural and alkali electrolyte solution. Well-defined TiN nanoarrays contribute a much higher capacitance performance than titania (TiO{sub 2}) in the supercapacitor application due to the extraordinarily improved electrical conductivity. Such an electrochemical capacitance can be further enhanced by increasing aspect ratio of TiN nanoarray from short nanotubes to long nanopores. A flexible supercapacitor has been constructed using two symmetrical TiN nanoarray electrodes and a polyvinyl alcohol (PVA) gel electrolyte with H{sub 2}SO{sub 4}–KCl–H{sub 2}O–EG. Such a supercapacitor has a highly improved potential window and still keeps good electrochemical energy storage. TiN nanoarray with a high aspect ratio can act well as an ultra thin film electrode material of flexible supercapacitor to contribute a superior capacitance performance.

  3. Deep level transient spectroscopy and minority carrier lifetime study on Ga-doped continuous Czochralski silicon

    Yoon, Yohan; Yan, Yixin; Ostrom, Nels P.; Kim, Jinwoo; Rozgonyi, George

    2012-11-01

    Continuous-Czochralski (c-Cz) crystal growth has been suggested as a viable technique for the fabrication of photovoltaic Si wafers due to its low resistivity variation of any dopant, independent of segregation, compared to conventional Cz. In order to eliminate light induced degradation due to boron-oxygen traps in conventional p-type silicon wafers, gallium doped wafers have been grown by c-Cz method and investigated using four point probe, deep level transient spectroscopy (DLTS), and microwave-photoconductance decay. Iron-gallium related electrically active defects were identified using DLTS as the main lifetime killers responsible for reduced non-uniform lifetimes in radial and axial positions of the c-Cz silicon ingot. A direct correlation between minority carrier lifetime and the concentration of electrically active Fe-Ga pairs was established.

  4. Mathematical modelling of heat production in deep geological repository of high-level nuclear waste

    Kovanda, O.

    2017-01-01

    Waste produced by nuclear industry requires special handling. Currently, there is a research taking place, focused at possibilities of nuclear waste storage in deep geological repositories, hosted in stable geological environment. The high-level nuclear waste produces significant amount of heat for a long time, which can affect either environment outside of or within the repository in a negative way. Therefore to reduce risks, it is desirable to know the principles of such heat production, which can be achieved using mathematical modeling. This thesis comes up with a general model of heat production-time dependency, dependable on initial composition of the waste. To be able to model real situations, output of this thesis needs to be utilized in an IT solution. (authors)

  5. Inductively coupled plasma induced deep levels in epitaxial n-GaAs

    Auret, F.D.; Janse van Rensburg, P.J.; Meyer, W.E.; Coelho, S.M.M.; Kolkovsky, Vl.; Botha, J.R.; Nyamhere, C.; Venter, A.

    2012-01-01

    The electronic properties of defects introduced by low energy inductively coupled Ar plasma etching of n-type (Si doped) GaAs were investigated by deep level transient spectroscopy (DLTS) and Laplace DLTS. Several prominent electron traps (E c —0.046 eV, E c —0.186 eV, E c —0.314 eV. E c —0.528 eV and E c —0.605 eV) were detected. The metastable defect E c —0.046 eV having a trap signature similar to E1 is observed for the first time. E c —0.314 eV and E c —0.605 eV are metastable and appear to be similar to the M3 and M4 defects present in dc H-plasma exposed GaAs.

  6. OPG's deep geologic repository for low and intermediate level waste - recent progress

    King, F.K.

    2006-01-01

    This paper provides a status report on Canada's first project to build a permanent repository for the long-term management of radioactive waste. Ontario Power Generation has initiated a project to construct a deep geologic repository for low- and intermediate-level waste at the Bruce Nuclear Site, at a depth in the range of 600 to 800 m in an Ordovician-age argillaceous limestone formation. The project is currently undergoing an Environmental Assessment and consulting companies in the areas of environmental assessment, geoscientific site characterization, engineering and safety assessment have been hired and technical studies are underway. Seismic surveys and borehole drilling will be initiated in the fall of 2006. The next major milestone for the project is the submission of the Environmental Assessment report, currently scheduled for December 2008. (author)

  7. Anomalous behaviors of E1/E2 deep level defects in 6H silicon carbide

    Chen, X.D.; Ling, C.C.; Gong, M.; Fung, S.; Beling, C.D.; Brauer, G.; Anwand, W.; Skorupa, W.

    2005-01-01

    Deep level defects E 1 /E 2 were observed in He-implanted, 0.3 and 1.7 MeV electron-irradiated n-type 6H-SiC. Similar to others' results, the behaviors of E 1 and E 2 (like the peak intensity ratio, the annealing behaviors or the introduction rates) often varied from sample to sample. This anomalous result is not expected of E 1 /E 2 being usually considered arising from the same defect located at the cubic and hexagonal sites respectively. The present study shows that this anomaly is due to another DLTS peak overlapping with the E 1 /E 2 . The activation energy and the capture cross section of this defect are E C -0.31 eV and σ∼8x10 -14 cm 2 , respectively

  8. Identities of the deep level defects E1/E2 in 6H silicon carbide

    Ling, C.C.; Chen, X.D.; Beling, C.D.; Fung, S.; Lam, T.W.; Lam, C.H.; Gong, M.; Weng, H.M.; Hang, D.S.

    2004-01-01

    E 1 /E 2 (E C -0.36/0.44 eV) are deep level donors generally found in ion-implanted, electron and neutron irradiated n-type 6H-SiC materials. Their configurations are controversial and have been related to a negatively charged carbon vacancy, a divacancy or a V Si -complex. With positron lifetime technique, we have identified V Si and V C V Si in the Lely grown n-type 6H-SiC sample, with V Si annealed out at 650 C. Concentration of V C V Si persists at 1400 C annealing and significantly decreased after the 1600 C annealing. Considering the deep level transient spectroscopic (DLTS) results on the neutron irradiated n-type SiC epi sample that E 1 /E 2 completely disappeared after the 1400 C annealing, E 1 /E 2 is not the V C V Si defect. With positron annihilation techniques, A. A. Rempel et al (2002) have shown the energy dependence of vacancy generated by electron irradiation. With low irradiation energy of 0.3MeV, only V C was generated and at higher energy (0.5MeV), Si vacancy was detected. With focus to find the minimum energy for generating E 1 /E 2 , we have performed DLTS studies on n-type epi 6H-SiC materials irradiated by electrons with varying energies. Our results suggest that E 1 /E 2 have microstructure related to a carbon vacancy or a carbon interstitial. (orig.)

  9. Solar Cell Capacitance Determination Based on an RLC Resonant Circuit

    Petru Adrian Cotfas

    2018-03-01

    Full Text Available The capacitance is one of the key dynamic parameters of solar cells, which can provide essential information regarding the quality and health state of the cell. However, the measurement of this parameter is not a trivial task, as it typically requires high accuracy instruments using, e.g., electrical impedance spectroscopy (IS. This paper introduces a simple and effective method to determine the electric capacitance of the solar cells. An RLC (Resistor Inductance Capacitor circuit is formed by using an inductor as a load for the solar cell. The capacitance of the solar cell is found by measuring the frequency of the damped oscillation that occurs at the moment of connecting the inductor to the solar cell. The study is performed through simulation based on National Instruments (NI Multisim application as SPICE simulation software and through experimental capacitance measurements of a monocrystalline silicon commercial solar cell and a photovoltaic panel using the proposed method. The results were validated using impedance spectroscopy. The differences between the capacitance values obtained by the two methods are of 1% for the solar cells and of 9.6% for the PV panel. The irradiance level effect upon the solar cell capacitance was studied obtaining an increase in the capacitance in function of the irradiance. By connecting different inductors to the solar cell, the frequency effect upon the solar cell capacitance was studied noticing a very small decrease in the capacitance with the frequency. Additionally, the temperature effect over the solar cell capacitance was studied achieving an increase in capacitance with temperature.

  10. Profiling of barrier capacitance and spreading resistance using a transient linearly increasing voltage technique.

    Gaubas, E; Ceponis, T; Kusakovskij, J

    2011-08-01

    A technique for the combined measurement of barrier capacitance and spreading resistance profiles using a linearly increasing voltage pulse is presented. The technique is based on the measurement and analysis of current transients, due to the barrier and diffusion capacitance, and the spreading resistance, between a needle probe and sample. To control the impact of deep traps in the barrier capacitance, a steady state bias illumination with infrared light was employed. Measurements of the spreading resistance and barrier capacitance profiles using a stepwise positioned probe on cross sectioned silicon pin diodes and pnp structures are presented.

  11. Dynamics of the deep-level emission in ZnO nanowires

    Hou, Dongchao; Rueckmann, Ilja; Voss, Tobias [Institut fuer Festkoerperphysik, Universitaet Bremen (Germany)

    2010-07-01

    Due to its wide direct band gap and large exciton binding energy (60 meV), ZnO nanowires possess an efficient near band-edge emission (NBE) in UV range. Additional energy levels in the band gap of ZnO, commonly introduced by point defects such as oxygen or zinc vacancies and Cu impurities, can largely weaken the UV emission by providing extra recombination routes for the electrons in conduction band. In ZnO nanowires this deep-level emission band (DLE) is expected to be largely activated by tunneling processes of holes trapped in the surface depletion layer after optical excitation. We studied the dependence of the DLE and NBE intensities of ZnO nanowires on the excitation power at different temperatures. For the experiments, the fundamental (1064 nm) and frequency-tripled (355 nm) pulses of an Nd:YAG microchip laser were used. The additional infrared laser radiation was used to directly populate the defect levels with electrons from the valence band. Our results show that the additional infrared photons lead to a reduction of the DLE while the NBE is enhanced. We discuss the implications of our results for the models of DLE in ZnO nanowires.

  12. Deep repository for long-lived low- and intermediate-level waste. Preliminary safety assessment

    1999-11-01

    A preliminary safety assessment has been performed of a deep repository for long-lived low- and intermediate-level waste, SFL 3-5. The purpose of the study is to investigate the capacity of the facility to act as a barrier to the release of radionuclides and toxic pollutants, and to shed light on the importance of the location of the repository site. A safety assessment (SR 97) of a deep repository for spent fuel has been carried out at the same time. In SR 97, three hypothetical repository sites have been selected for study. These sites exhibit fairly different conditions in terms of hydrogeology, hydrochemistry and ecosystems. To make use of information and data from the SR 97 study, we have assumed that SFL 3-5 is co-sited with the deep repository for spent fuel. A conceivable alternative is to site SFL 3-5 as a completely separate repository. The focus of the SFL 3-5 study is a quantitative analysis of the environmental impact for a reference scenario, while other scenarios are discussed and analyzed in more general terms. Migration in the repository's near- and far-field has been taken into account in the reference scenario. Environmental impact on the three sites has also been calculated. The calculations are based on an updated forecast of the waste to be disposed of in SFL 3-5. The forecast includes radionuclide content, toxic metals and other substances that have a bearing on a safety assessment. The safety assessment shows how important the site is for safety. Two factors stand out as being particularly important: the water flow at the depth in the rock where the repository is built, and the ecosystem in the areas on the ground surface where releases may take place in the future. Another conclusion is that radionuclides that are highly mobile and long-lived, such as 36 Cl and 93 Mo , are important to take into consideration. Their being long-lived means that barriers and the ecosystems must be regarded with a very long time horizon

  13. Deep repository for long-lived low- and intermediate-level waste. Preliminary safety assessment

    NONE

    1999-11-01

    A preliminary safety assessment has been performed of a deep repository for long-lived low- and intermediate-level waste, SFL 3-5. The purpose of the study is to investigate the capacity of the facility to act as a barrier to the release of radionuclides and toxic pollutants, and to shed light on the importance of the location of the repository site. A safety assessment (SR 97) of a deep repository for spent fuel has been carried out at the same time. In SR 97, three hypothetical repository sites have been selected for study. These sites exhibit fairly different conditions in terms of hydrogeology, hydrochemistry and ecosystems. To make use of information and data from the SR 97 study, we have assumed that SFL 3-5 is co-sited with the deep repository for spent fuel. A conceivable alternative is to site SFL 3-5 as a completely separate repository. The focus of the SFL 3-5 study is a quantitative analysis of the environmental impact for a reference scenario, while other scenarios are discussed and analyzed in more general terms. Migration in the repository's near- and far-field has been taken into account in the reference scenario. Environmental impact on the three sites has also been calculated. The calculations are based on an updated forecast of the waste to be disposed of in SFL 3-5. The forecast includes radionuclide content, toxic metals and other substances that have a bearing on a safety assessment. The safety assessment shows how important the site is for safety. Two factors stand out as being particularly important: the water flow at the depth in the rock where the repository is built, and the ecosystem in the areas on the ground surface where releases may take place in the future. Another conclusion is that radionuclides that are highly mobile and long-lived, such as {sup 36}Cl and {sup 93}Mo , are important to take into consideration. Their being long-lived means that barriers and the ecosystems must be regarded with a very long time horizon.

  14. The effects of deep level traps on the electrical properties of semi-insulating CdZnTe

    Zha, Gangqiang; Yang, Jian; Xu, Lingyan; Feng, Tao; Wang, Ning; Jie, Wanqi [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an (China)

    2014-01-28

    Deep level traps have considerable effects on the electrical properties and radiation detection performance of high resistivity CdZnTe. A deep-trap model for high resistivity CdZnTe was proposed in this paper. The high resistivity mechanism and the electrical properties were analyzed based on this model. High resistivity CdZnTe with high trap ionization energy E{sub t} can withstand high bias voltages. The leakage current is dependent on both the deep traps and the shallow impurities. The performance of a CdZnTe radiation detector will deteriorate at low temperatures, and the way in which sub-bandgap light excitation could improve the low temperature performance can be explained using the deep trap model.

  15. Pixel-Level Deep Segmentation: Artificial Intelligence Quantifies Muscle on Computed Tomography for Body Morphometric Analysis.

    Lee, Hyunkwang; Troschel, Fabian M; Tajmir, Shahein; Fuchs, Georg; Mario, Julia; Fintelmann, Florian J; Do, Synho

    2017-08-01

    Pretreatment risk stratification is key for personalized medicine. While many physicians rely on an "eyeball test" to assess whether patients will tolerate major surgery or chemotherapy, "eyeballing" is inherently subjective and difficult to quantify. The concept of morphometric age derived from cross-sectional imaging has been found to correlate well with outcomes such as length of stay, morbidity, and mortality. However, the determination of the morphometric age is time intensive and requires highly trained experts. In this study, we propose a fully automated deep learning system for the segmentation of skeletal muscle cross-sectional area (CSA) on an axial computed tomography image taken at the third lumbar vertebra. We utilized a fully automated deep segmentation model derived from an extended implementation of a fully convolutional network with weight initialization of an ImageNet pre-trained model, followed by post processing to eliminate intramuscular fat for a more accurate analysis. This experiment was conducted by varying window level (WL), window width (WW), and bit resolutions in order to better understand the effects of the parameters on the model performance. Our best model, fine-tuned on 250 training images and ground truth labels, achieves 0.93 ± 0.02 Dice similarity coefficient (DSC) and 3.68 ± 2.29% difference between predicted and ground truth muscle CSA on 150 held-out test cases. Ultimately, the fully automated segmentation system can be embedded into the clinical environment to accelerate the quantification of muscle and expanded to volume analysis of 3D datasets.

  16. Capacitive gauging apparatus

    Walton, H.

    1985-01-01

    Apparatus for gauging physical dimensions of solid or tubular bodies (e.g. a nuclear fuel pellet) comprises a capacitive transducer having electrodes forming diametrically arranged pairs of capacitors and means for connecting the pairs, preferably sequentially, in an arm of a four arm electrical network. For circumferential scanning of a solid body along its length, the body is moved along a path of travel through head assembly including the transducer by means of plungers with the axis of the body being coincident with the axis of the transducer. As the body moves through the transducer the diametrically arranged pairs of capacitors scan the surface to result in a surface profile of the body. For scanning the bore of a pipe or tube the transducer is inserted as a probe and moved along the bore of the pipe or tube, means being provided for maintaining the probe coaxial with the pipe or tube. (author)

  17. Chloroplast phylogenomic analyses resolve deep-level relationships of an intractable bamboo tribe Arundinarieae (poaceae).

    Ma, Peng-Fei; Zhang, Yu-Xiao; Zeng, Chun-Xia; Guo, Zhen-Hua; Li, De-Zhu

    2014-11-01

    The temperate woody bamboos constitute a distinct tribe Arundinarieae (Poaceae: Bambusoideae) with high species diversity. Estimating phylogenetic relationships among the 11 major lineages of Arundinarieae has been particularly difficult, owing to a possible rapid radiation and the extremely low rate of sequence divergence. Here, we explore the use of chloroplast genome sequencing for phylogenetic inference. We sampled 25 species (22 temperate bamboos and 3 outgroups) for the complete genome representing eight major lineages of Arundinarieae in an attempt to resolve backbone relationships. Phylogenetic analyses of coding versus noncoding sequences, and of different regions of the genome (large single copy and small single copy, and inverted repeat regions) yielded no well-supported contradicting topologies but potential incongruence was found between the coding and noncoding sequences. The use of various data partitioning schemes in analysis of the complete sequences resulted in nearly identical topologies and node support values, although the partitioning schemes were decisively different from each other as to the fit to the data. Our full genomic data set substantially increased resolution along the backbone and provided strong support for most relationships despite the very short internodes and long branches in the tree. The inferred relationships were also robust to potential confounding factors (e.g., long-branch attraction) and received support from independent indels in the genome. We then added taxa from the three Arundinarieae lineages that were not included in the full-genome data set; each of these were sampled for more than 50% genome sequences. The resulting trees not only corroborated the reconstructed deep-level relationships but also largely resolved the phylogenetic placements of these three additional lineages. Furthermore, adding 129 additional taxa sampled for only eight chloroplast loci to the combined data set yielded almost identical

  18. Efficiency of Capacitively Loaded Converters

    Andersen, Thomas; Huang, Lina; Andersen, Michael A. E.

    2012-01-01

    This paper explores the characteristic of capacitance versus voltage for dielectric electro active polymer (DEAP) actuator, 2kV polypropylene film capacitor as well as 3kV X7R multi layer ceramic capacitor (MLCC) at the beginning. An energy efficiency for capacitively loaded converters...... is introduced as a definition of efficiency. The calculated and measured efficiency curves for charging DEAP actuator, polypropylene film capacitor and X7R MLCC are provided and compared. The attention has to be paid for the voltage dependent capacitive load, like X7R MLCC, when evaluating the charging...... polypropylene film capacitor can be the equivalent capacitive load. Because of the voltage dependent characteristic, X7R MLCC cannot be used to replace the DEAP actuator. However, this type of capacitor can be used to substitute the capacitive actuator with voltage dependent property at the development phase....

  19. Deep levels in p-type InGaAsN lattice matched to GaAs

    Kwon, D.; Kaplar, R.J.; Ringel, S.A.; Allerman, A.A.; Kurtz, S.R.; Jones, E.D.

    1999-01-01

    Deep-level transient spectroscopy measurements were utilized to investigate deep-level defects in metal - organic chemical vapor deposition-grown, unintentionally doped p-type InGaAsN films lattice matched to GaAs. The as-grown material displayed a high concentration of deep levels distributed within the band gap, with a dominant hole trap at E v +0.10eV. Postgrowth annealing simplified the deep-level spectra, enabling the identification of three distinct hole traps at 0.10, 0.23, and 0.48 eV above the valence-band edge, with concentrations of 3.5x10 14 , 3.8x10 14 , and 8.2x10 14 cm -3 , respectively. A direct comparison between the as-grown and annealed spectra revealed the presence of an additional midgap hole trap, with a concentration of 4x10 14 cm -3 in the as-grown material. The concentration of this trap is sharply reduced by annealing, which correlates with improved material quality and minority-carrier properties after annealing. Of the four hole traps detected, only the 0.48 eV level is not influenced by annealing, suggesting this level may be important for processed InGaAsN devices in the future. copyright 1999 American Institute of Physics

  20. DNCON2: improved protein contact prediction using two-level deep convolutional neural networks.

    Adhikari, Badri; Hou, Jie; Cheng, Jianlin

    2018-05-01

    Significant improvements in the prediction of protein residue-residue contacts are observed in the recent years. These contacts, predicted using a variety of coevolution-based and machine learning methods, are the key contributors to the recent progress in ab initio protein structure prediction, as demonstrated in the recent CASP experiments. Continuing the development of new methods to reliably predict contact maps is essential to further improve ab initio structure prediction. In this paper we discuss DNCON2, an improved protein contact map predictor based on two-level deep convolutional neural networks. It consists of six convolutional neural networks-the first five predict contacts at 6, 7.5, 8, 8.5 and 10 Å distance thresholds, and the last one uses these five predictions as additional features to predict final contact maps. On the free-modeling datasets in CASP10, 11 and 12 experiments, DNCON2 achieves mean precisions of 35, 50 and 53.4%, respectively, higher than 30.6% by MetaPSICOV on CASP10 dataset, 34% by MetaPSICOV on CASP11 dataset and 46.3% by Raptor-X on CASP12 dataset, when top L/5 long-range contacts are evaluated. We attribute the improved performance of DNCON2 to the inclusion of short- and medium-range contacts into training, two-level approach to prediction, use of the state-of-the-art optimization and activation functions, and a novel deep learning architecture that allows each filter in a convolutional layer to access all the input features of a protein of arbitrary length. The web server of DNCON2 is at http://sysbio.rnet.missouri.edu/dncon2/ where training and testing datasets as well as the predictions for CASP10, 11 and 12 free-modeling datasets can also be downloaded. Its source code is available at https://github.com/multicom-toolbox/DNCON2/. chengji@missouri.edu. Supplementary data are available at Bioinformatics online.

  1. Subgap time of flight: A spectroscopic study of deep levels in semi-insulating CdTe:Cl

    Pousset, J.; Farella, I.; Cola, A., E-mail: adriano.cola@le.imm.cnr.it [Institute for Microelectronics and Microsystems—Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Gambino, S. [Dipartimento di Matematica e Fisica “Ennio De Giorgi,” Università del Salento, Lecce I-73100 (Italy); CNR NANOTEC—Istituto di Nanotecnologia, Polo di Nanotecnologia c/o Campus Ecotekne, via Monteroni, 73100 Lecce (Italy)

    2016-03-14

    We report on a study of deep levels in semi-insulating CdTe:Cl by means of a time-of-flight spectral approach. By varying the wavelength of a pulsed optical source within the CdTe energy gap, transitions to/from localized levels generate free carriers which are analysed through the induced photocurrent transients. Both acceptor-like centers, related to the A-center, and a midgap level, 0.725 eV from the valence band, have been detected. The midgap level is close to the Fermi level and is possibly a recombination center responsible for the compensation mechanism. When the irradiance is varied, either linear or quadratic dependence of the electron and hole collected charge are observed, depending on the dominant optical transitions. The analysis discloses the potentiality of such a novel approach exploitable in the field of photorefractive materials as well as for deep levels spectroscopy.

  2. Subgap time of flight: A spectroscopic study of deep levels in semi-insulating CdTe:Cl

    Pousset, J.; Farella, I.; Cola, A.; Gambino, S.

    2016-01-01

    We report on a study of deep levels in semi-insulating CdTe:Cl by means of a time-of-flight spectral approach. By varying the wavelength of a pulsed optical source within the CdTe energy gap, transitions to/from localized levels generate free carriers which are analysed through the induced photocurrent transients. Both acceptor-like centers, related to the A-center, and a midgap level, 0.725 eV from the valence band, have been detected. The midgap level is close to the Fermi level and is possibly a recombination center responsible for the compensation mechanism. When the irradiance is varied, either linear or quadratic dependence of the electron and hole collected charge are observed, depending on the dominant optical transitions. The analysis discloses the potentiality of such a novel approach exploitable in the field of photorefractive materials as well as for deep levels spectroscopy.

  3. Positron deep-level transient spectroscopy in semi-insulating-GaAs using the positron velocity transient method

    Tsia, M.; Fung, S.; Beling, C.D.

    2001-01-01

    Recently a new semiconductor defect spectroscopy, namely positron deep level transient spectroscopy (PDLTS) has been proposed that combines the energy selectivity of deep level transient spectroscopy with the structural sensitivity of positron annihilation spectroscopy. This paper focuses on one variant of PDLTS, namely positron velocity PDLTS, which has no sensitivity towards vacancy defects but nevertheless is useful in studying deep levels in semi-insulators. In the present study the electric field within the depletion region of semi-insulating GaAs is monitored through the measurement of the small Doppler shift in the annihilation radiation that comes from this region as a result of positron drift. The drift is the result of an increasing electric field produced by space charge building up from ionizing deep level defects. Doppler shift transients are measured between 50-300 K. The EL2 level emission transients are clearly seen at temperatures around 300 K that yield E C -0.78±0.08eV for the energy of EL2. The EL2 electron capture rate is found to have an activation energy of 0.61±0.08eV which most probably arises from freeze out of conduction electrons. We find the surprising result that emission and capture transients can be seen at temperatures below 200 K. Possible reasons for these transients are discussed. (orig.)

  4. Capacitance properties and simulation of the AlGaN/GaN Schottky heterostructure

    Harmatha, Ladislav; Ľubica, Stuchlíková; Juraj, Racko; Juraj, Marek; Juraj, Pecháček; Peter, Benko; Michal, Nemec; Juraj, Breza

    2014-01-01

    Highlights: • Dependences of CV characteristics of the AlGaN/GaN structure on frequency and temperature variations. • Identification of electrical activity of defects by capacitance DLTS. • Simulating the properties of the GaN/Al 0.2 GaN 0.8 /GaN Schottky heterostructure. - Abstract: The paper presents the results of capacitance measurements on GaN/AlGaN/GaN Schottky heterostructures grown on an Al 2 O 3 substrate by Low-Pressure Metal–Organic Vapour-Phase Epitaxy (LP-MOVPE). Dependences of the capacitance–voltage (CV) characteristics on the frequency of the measuring signal allow analysing the properties of the 2D electron gas (2DEG) at the AlGaN/GaN heterojunction. Exact location of the hetero-interface below the surface (20 nm) was determined from the concentration profile. Temperature variations of the CV curves reveal the influence of bulk defects in GaN and of the traps at the AlGaN/GaN interface. Electrical activity of these defects was characterized by capacitance Deep Level Transient Fourier Spectroscopy (DLTFS). Experimental results of CV measurements were supported by simulating the properties of the GaN/Al 0.2 GaN 0.8 /GaN Schottky heterostructure in dependence on the influence of the concentration of donor-like traps in GaN and of the temperature upon the CV curves

  5. Capacitive Sensing of Glucose in Electrolytes Using Graphene Quantum Capacitance Varactors.

    Zhang, Yao; Ma, Rui; Zhen, Xue V; Kudva, Yogish C; Bühlmann, Philippe; Koester, Steven J

    2017-11-08

    A novel graphene-based variable capacitor (varactor) that senses glucose based on the quantum capacitance effect was successfully developed. The sensor utilizes a metal-oxide-graphene varactor device structure that is inherently compatible with passive wireless sensing, a key advantage for in vivo glucose sensing. The graphene varactors were functionalized with pyrene-1-boronic acid (PBA) by self-assembly driven by π-π interactions. Successful surface functionalization was confirmed by both Raman spectroscopy and capacitance-voltage characterization of the devices. Through glucose binding to the PBA, the glucose concentration in the buffer solutions modulates the level of electrostatic doping of the graphene surface to different degrees, which leads to capacitance changes and Dirac voltage shifts. These responses to the glucose concentration were shown to be reproducible and reversible over multiple measurement cycles, suggesting promise for eventual use in wireless glucose monitoring.

  6. Ferroelectric negative capacitance domain dynamics

    Hoffmann, Michael; Khan, Asif Islam; Serrao, Claudy; Lu, Zhongyuan; Salahuddin, Sayeef; Pešić, Milan; Slesazeck, Stefan; Schroeder, Uwe; Mikolajick, Thomas

    2018-05-01

    Transient negative capacitance effects in epitaxial ferroelectric Pb(Zr0.2Ti0.8)O3 capacitors are investigated with a focus on the dynamical switching behavior governed by domain nucleation and growth. Voltage pulses are applied to a series connection of the ferroelectric capacitor and a resistor to directly measure the ferroelectric negative capacitance during switching. A time-dependent Ginzburg-Landau approach is used to investigate the underlying domain dynamics. The transient negative capacitance is shown to originate from reverse domain nucleation and unrestricted domain growth. However, with the onset of domain coalescence, the capacitance becomes positive again. The persistence of the negative capacitance state is therefore limited by the speed of domain wall motion. By changing the applied electric field, capacitor area or external resistance, this domain wall velocity can be varied predictably over several orders of magnitude. Additionally, detailed insights into the intrinsic material properties of the ferroelectric are obtainable through these measurements. A new method for reliable extraction of the average negative capacitance of the ferroelectric is presented. Furthermore, a simple analytical model is developed, which accurately describes the negative capacitance transient time as a function of the material properties and the experimental boundary conditions.

  7. A poor sealing Scenario for Deep disposal of high level waste

    Weetjens, E.

    2005-01-01

    Especially for geological disposal options in clay, the safety of the repository relies chiefly on the performance of the host formation as the main barrier. Understandably, scenarios in which this clay barrier is somehow bypassed earn great concern in PA (Performance Assessment) studies. The Poor Sealing Scenario is one of those scenarios that have been recently studied by the PA section of the Waste and Disposal department in the framework of the Belgian programme on deep disposal of high-level radwaste in Boom Clay. This scenario hypothesises that at least one disposal gallery and an access shaft have been poorly sealed off, providing a preferential pathway for RNs (radionuclides). The scenario further assumes a severe climate change, which would invert the presently downward hydraulic gradient, such that the potential impact would be maximal. The main objective is assessing the contribution from two transport processes to the overall radionuclide migration from a spent fuel repository towards the Neogene aquifer. The processes considered are advective transport through the poorly sealed repository and diffusive transport through the host formation. In addition, we would like to identify the most influential parameters with respect to repository design and performance

  8. Electrical characterization of deep levels in n-type GaAs after hydrogen plasma treatment

    Nyamhere, C.; Botha, J.R.; Venter, A.

    2011-01-01

    Deep level transient spectroscopy (DLTS) and Laplace-DLTS (L-DLTS) have been used to investigate defects in an n-type GaAs before and after exposure to a dc hydrogen plasma (hydrogenation). DLTS revealed the presence of three prominent electron traps in the material in the temperature range 20-300 K. However, L-DLTS with its higher resolution enabled the splitting of two narrowly spaced emission rates. Consequently four electron traps at, E C -0.33 eV, E C -0.36 eV, E C -0.38 eV and E C -0.56 eV were observed in the control sample. Following hydrogenation, all these traps were passivated with a new complex (presumably the M3), emerging at E C -0.58 eV. Isochronal annealing of the passivated material between 50 and 300 o C, revealed the emergence of a secondary defect, not previously observed, at E C -0.37 eV. Finally, the effect of hydrogen passivation is completely reversed upon annealing at 300 o C, as all the defects originally observed in the reference sample were recovered.

  9. Electrical characterization of deep levels in n-type GaAs after hydrogen plasma treatment

    Nyamhere, C., E-mail: s210239522@live.nmmu.ac.z [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Botha, J.R.; Venter, A. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2011-05-15

    Deep level transient spectroscopy (DLTS) and Laplace-DLTS (L-DLTS) have been used to investigate defects in an n-type GaAs before and after exposure to a dc hydrogen plasma (hydrogenation). DLTS revealed the presence of three prominent electron traps in the material in the temperature range 20-300 K. However, L-DLTS with its higher resolution enabled the splitting of two narrowly spaced emission rates. Consequently four electron traps at, E{sub C}-0.33 eV, E{sub C}-0.36 eV, E{sub C}-0.38 eV and E{sub C}-0.56 eV were observed in the control sample. Following hydrogenation, all these traps were passivated with a new complex (presumably the M3), emerging at E{sub C}-0.58 eV. Isochronal annealing of the passivated material between 50 and 300 {sup o}C, revealed the emergence of a secondary defect, not previously observed, at E{sub C}-0.37 eV. Finally, the effect of hydrogen passivation is completely reversed upon annealing at 300 {sup o}C, as all the defects originally observed in the reference sample were recovered.

  10. Inductively coupled plasma induced deep levels in epitaxial n-GaAs

    Auret, F.D.; Janse van Rensburg, P.J.; Meyer, W.E.; Coelho, S.M.M. [Department of Physics, University of the Pretoria, Lynnwood Road, Pretoria 0002 (South Africa); Kolkovsky, Vl. [Technische Universitaet, Dresden, 01062 Dresden (Germany); Botha, J.R.; Nyamhere, C. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Venter, A., E-mail: andre.venter@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2012-05-15

    The electronic properties of defects introduced by low energy inductively coupled Ar plasma etching of n-type (Si doped) GaAs were investigated by deep level transient spectroscopy (DLTS) and Laplace DLTS. Several prominent electron traps (E{sub c}-0.046 eV, E{sub c}-0.186 eV, E{sub c}-0.314 eV. E{sub c}-0.528 eV and E{sub c}-0.605 eV) were detected. The metastable defect E{sub c}-0.046 eV having a trap signature similar to E1 is observed for the first time. E{sub c}-0.314 eV and E{sub c}-0.605 eV are metastable and appear to be similar to the M3 and M4 defects present in dc H-plasma exposed GaAs.

  11. Environmental assessment for OPG's deep geologic repository for low and intermediate level waste

    Barker, D.; Rawlings, M.; Beal, A.

    2011-01-01

    The environmental assessment process for the Deep Geologic Repository (DGR) Project was initiated very early in the planning stages. Feasibility studies were initiated in 2003, after Ontario Power Generation (OPG) and the Municipality of Kincardine signed a Memorandum of Understanding agreeing to assess options for long-term management of low and intermediate level waste (L and ILW) options at the Bruce nuclear site. The location of the DGR, in the Municipality of Kincardine, is based on a willing and informed host community. The preferred approach, the DGR at the Bruce nuclear site, was advanced based on results of feasibility studies which looked at a number of options for long-term management of L&ILW and support from the local community and their elected representatives. The federal environmental assessment of the project was initiated following the signing of a Host Community Agreement and completion of a telephone poll, the results of which indicated that the majority of Municipality of Kincardine residents support the project. The environmental assessment began in 2006 as a comprehensive study and was ultimately referred to a joint review panel process in 2009. The environmental assessment considers the potential near-term effects of the construction and operations of the proposed project. Because of the nature of the project, the assessment of effects also considers long-term effects extending out to the million year time-frame, including effects of climate change, glaciations and seismic activity. (author)

  12. The study of fracture mineralization and relationship with high level radioactive waste of deep geological repository

    Reyes, Cristina N.

    2003-01-01

    Extensive investigations of the Ordovician, Dinantian and Permo-Triassic rocks of the Sellafield area of northwest England were undertaken by United Kingdom Nirex Ltd. as a possible national site for geological disposal of intermediate and low-level radioactive waste. Very detailed studies of fracture mineralisation at Sellafield were thus put in hand by Nirex Ltd. and the results summarised by the British Geological Survey. Deep (up to 2 km) boreholes were put down with excellent core recovery. It is generally agreed that the most significant pathway for the escape of all but a very few radionuclides is by solution in and advection of groundwater. In this context, rock fracture systems are particularly important because they offer a potentially rapid pathway to the surface and the biosphere. One striking aspect of this work is that the fracture mineralisation seemingly records major and rapid fluctuations in redox conditions -sometimes during apparently continuous precipitation of cements (ferroan and non-ferroan calcites, dolomite). Carbonate cements record variations in Fe 2+ availability. Fe(III) precipitates also as oxide (hematite) and Fe(II) as sulphide (pyrite). This study focuses on these elements and valence states and also on Mn; another element susceptible to redox controls but known to respond differently from Fe. Shallow sub-surface stores or repositories would be more likely to have oxidising or fluctuating redox conditions. The mineralisation sequences documented at Sellafield are potentially promising in this context. Ferroan carbonate cements are sensitive indicators of later movement of oxidising ground waters. (author)

  13. Application of systems analysis to the disposal of high level waste in deep ocean sediments

    De Marsily, G.; Dorp, F. van

    1982-01-01

    Emplacement in deep ocean sediments is one of the disposal options being considered for solidified high level radioactive waste. Task groups set up within the framework of the NEA Seabed Working Group have been studying many aspects of this option since 1976. The methods of systems analysis have been applied to enable the various parts of the problem to be assessed within an integrated framework. This paper describes the progress made by the Systems Analysis Task Group towards the development of an overall system model. The Task Group began by separating the problem into elements and defining the interfaces between these elements. A simple overall system model was then developed and used in both a preliminary assessment and a sensitivity analysis to identify the most important parameters. These preliminary analyses used a very simple model of the overall system and therefore the results cannot be used to draw any conclusions as to the acceptability of the sub-seabed disposal option. However they served to show the utility of the systems analysis method. The work of the other task groups will focus on the important parameters so that improved results can be fed back into an improved system model. Subsequent iterations will eventually provide an input to an acceptability decision. (Auth.)

  14. Total circulating microparticle levels are increased in patients with deep infiltrating endometriosis.

    Munrós, J; Martínez-Zamora, M A; Tàssies, D; Coloma, J L; Torrente, M A; Reverter, J C; Carmona, F; Balasch, J

    2017-02-01

    Are the levels of total circulating cell-derived microparticles (cMPs) and circulating tissue factor-containing microparticles (cMP-TF) increased in patients with endometriosis? The levels of total cMP, but not cMP-TF, were higher in patients with endometriosis, and these were attributed to higher levels in patients with deep infiltrating endometriosis (DIE). Previous studies have reported elevated levels of total cMP in inflammatory conditions as well as higher levels of other inflammatory biomarkers in endometriosis. Increased expression of tissue factor (a transmembrane receptor for Factor VII/VIIa) in eutopic and ectopic endometrium from patients with endometriosis has been described. There is no previous data regarding total cMP and cMP-TF levels in patients with endometriosis. A prospective case-control study including two groups of patients was carried out. The E group included 65 patients with surgically confirmed endometriosis (37 with DIE lesions) and the C group comprises 33 women without surgical findings of any form of endometriosis. Patients and controls were recruited during the same 10-month period. Controls were the next patient without endometriosis undergoing surgery, after including two patients with endometriosis. Venous blood samples for total cMP and cMP-TF determinations were obtained at the time of surgery, before anesthesia at a tertiary care center. To assess total cMP, an ELISA functional assay was used and cMP-TF activity in plasma was measured using an ELISA kit. Total cMP levels in plasma were higher in the E group compared with the C group (P < 0.0001). The subanalysis of endometriosis patients with DIE or with ovarian endometriomas without DIE showed that total cMP levels were higher in the DIE group (P = 0.001). There were no statistically significant differences in cMP-TF levels among the groups analyzed. This is a preliminary study in which the sample size was arbitrarily decided, albeit in keeping with previous studies analyzing

  15. The Capacitive Magnetic Field Sensor

    Zyatkov, D. O.; Yurchenko, A. V.; Balashov, V. B.; Yurchenko, V. I.

    2016-01-01

    The results of a study of sensitive element magnetic field sensor are represented in this paper. The sensor is based on the change of the capacitance with an active dielectric (ferrofluid) due to the magnitude of magnetic field. To prepare the ferrofluid magnetic particles are used, which have a followingdispersion equal to 50 brand 5BDSR. The dependence of the sensitivity of the capacitive element from the ferrofluid with different dispersion of magnetic particles is considered. The threshold of sensitivity and sensitivity of a measuring cell with ferrofluid by a magnetic field was determined. The experimental graphs of capacitance change of the magnitude of magnetic field are presented.

  16. Virtual electrical capacitance tomography sensor

    Li, Y; Yang, W Q

    2005-01-01

    Electrical capacitance tomography (ECT) is an effective technique for elucidating the distribution of dielectric materials inside closed pipes or vessels. This paper describes a virtual electrical capacitance tomography (VECT) system, which can simulate a range of sensor and hardware configurations and material distributions. A selection of popular image reconstruction algorithms has been made available and image error and capacitance error tools enable their performance to be evaluated and compared. Series of frame-by-frame results can be stored for simulating real-time dynamic flows. The system is programmed in Matlab with DOS functions. It is convenient to use and low-cost to operate, providing an effective tool for engineering experiment

  17. Strategic program for deep geological disposal of high level radioactive waste in China

    Wang Ju

    2004-01-01

    A strategic program for deep geological disposal of high level radioactive waste in China is proposed in this paper. A '3-step technical strategy': site selection and site characterization-site specific underground research laboratory-final repository, is proposed for the development of China's high level radioactive waste repository. The activities related with site selection and site characterization for the repository can be combined with those for the underground research laboratory. The goal of the strategy is to build China's repository around 2040, while the activities can be divided into 4 phases: 1) site selection and site characterization; 2) site confirmation and construction of underground research laboratory, 3) in-situ experiment and disposal demonstration, and 4) construction of repository. The targets and tasks for each phase are proposed. The logistic relationship among the activities is discussed. It is pointed out that the site selection and site characterization provide the basis for the program, the fundamental study and underground research laboratory study are the key support, the performance assessment plays a guiding role, while the construction of a qualified repository is the final goal. The site selection can be divided into 3 stages: comparison among pre-selected areas, comparison among pre-selected sites and confirmation of the final site. According to this strategy, the final site for China's underground research laboratory and repository will be confirmed in 2015, where the construction of an underground laboratory will be started. In 2025 the underground laboratory will have been constructed, while in around 2040, the construction of a final repository is to be completed

  18. Charge deep-level transient spectroscopy study of high-energy-electron-beam-irradiated hydrogenated amorphous silicon

    Klaver, A.; Nádaždy, V.; Zeman, M.; Swaaiij, R.A.C.M.M.

    2006-01-01

    We present a study of changes in the defect density of states in hydrogenated amorphous silicon (a-Si:H) due to high-energy electron irradiation using charged deep-level transient spectroscopy. It was found that defect states near the conduction band were removed, while in other band gap regions the

  19. Benefiting from deep-level diversity : How congruence between knowledge and decision rules improves team decision making and team perceptions

    Rink, Floor; Ellemers, Naomi

    In two experiments we show how teams can benefit from the presence of multiple sources of deep-level task-related diversity. We manipulated differences (vs. similarities) in task information and personal decision rules in dyads (Study 1) and three-person teams (Study 2). The results indicate that

  20. I–V, C–V and deep level transient spectroscopy study of 24 MeV ...

    This paper describes the effect of 24 MeV proton irradiation on the electrical characteristics of a pnp bipolar junction transistor 2N 2905A. –, – and DLTS measurements are carried out to characterize the transistor before and after irradiation. The properties of deep level defects observed in the bulk of the transistor are ...

  1. Coseismic and aseismic deformations associated with mining-induced seismic events located in deep level mines in South Africa

    Milev, A

    2013-10-01

    Full Text Available Two underground sites in a deep level gold mine in South Africa were instrumented by the Council for Scientific and Industrial Research (CSIR) with tilt meters and seismic monitors. One of the sites was also instrumented by Japanese-German...

  2. Transforming Passive Receptivity of Knowledge into Deep Learning Experiences at the Undergraduate Level: An Example from Music Theory

    Ferenc, Anna

    2015-01-01

    This article discusses transformation of passive knowledge receptivity into experiences of deep learning in a lecture-based music theory course at the second-year undergraduate level through implementation of collaborative projects that evoke natural critical learning environments. It presents an example of such a project, addresses key features…

  3. Social stakes of the reversibility in the deep storage of high level radioactive wastes

    Heriard-Dubreuil, G.; Schieber, C.; Schneider, T.

    1998-06-01

    This document proposes a study of the conditions which surrounded the reversibility introduction in high activity wastes deep storage at an international scale, as well as a reflexion on the social stakes associated there. In France, the law of december 30, 1991 concerning the research on the radioactive wastes prescribes '' the study of possibilities retrieval or non retrieval storage in deep geological deposits''. The analysis of the reversibility associated social stakes emphasizes the necessity to prevent irreversible consequences, to take care to the choices reversibility, to preserve the future generations autonomy. Thus to elaborate a more satisfactory solution between deep disposal and surface storage, a deep storage, capable of gradually evolution, concept is defined. (A.L.B.)

  4. 3D capacitive tactile sensor using DRIE micromachining

    Chuang, Chiehtang; Chen, Rongshun

    2005-07-01

    This paper presents a three dimensional micro capacitive tactile sensor that can detect normal and shear forces which is fabricated using deep reactive ion etching (DRIE) bulk silicon micromachining. The tactile sensor consists of a force transmission plate, a symmetric suspension system, and comb electrodes. The sensing character is based on the changes of capacitance between coplanar sense electrodes. High sensitivity is achieved by using the high aspect ratio interdigital electrodes with narrow comb gaps and large overlap areas. The symmetric suspension mechanism of this sensor can easily solve the coupling problem of measurement and increase the stability of the structure. In this paper, the sensor structure is designed, the capacitance variation of the proposed device is theoretically analyzed, and the finite element analysis of mechanical behavior of the structures is performed.

  5. Adding Resistances and Capacitances in Introductory Electricity

    Efthimiou, C. J.; Llewellyn, R. A.

    2005-09-01

    All introductory physics textbooks, with or without calculus, cover the addition of both resistances and capacitances in series and in parallel as discrete summations. However, none includes problems that involve continuous versions of resistors in parallel or capacitors in series. This paper introduces a method for solving the continuous problems that is logical, straightforward, and within the mathematical preparation of students at the introductory level.

  6. Distribution of coronary arterial capacitance in a canine model.

    Lader, A S; Smith, R S; Phillips, G C; McNamee, J E; Abel, F L

    1998-03-01

    The capacitative properties of the major left coronary arteries, left main (LM), left anterior descending (LAD), and left circumflex (LCX), were studied in 19 open-chest isolated dog hearts. Capacitance was determined by using ramp perfusion and a left ventricular-to-coronary shunt diastolic decay method; both methods gave similar results, indicating a minimal systolic capacitative component. Increased pericardial pressure (PCP), 25 mmHg, was used to experimentally alter transmural wall pressure. The response to increased PCP was different in the LAD vs. LCX; increasing PCP decreased capacitance in the LCX but increased capacitance in the LAD. This may have been due to the different intramural vs. epicardial volume distribution of these vessels and a decrease in intramural tension during increased PCP. Increased PCP decreased LCX capacitance by approximately 13%, but no changes in conductance or zero flow pressure intercept occurred in any of the three vessels, i. e., evidence against the waterfall theory of vascular collapse at these levels of PCP. Coronary arterial capacitance was also linearly related to perfusion pressure.

  7. Ferroelectric Negative Capacitance Domain Dynamics

    Hoffmann, Michael; Khan, Asif Islam; Serrao, Claudy; Lu, Zhongyuan; Salahuddin, Sayeef; Pešić, Milan; Slesazeck, Stefan; Schroeder, Uwe; Mikolajick, Thomas

    2017-01-01

    Transient negative capacitance effects in epitaxial ferroelectric Pb(Zr$_{0.2}$Ti$_{0.8}$)O$_3$ capacitors are investigated with a focus on the dynamical switching behavior governed by domain nucleation and growth. Voltage pulses are applied to a series connection of the ferroelectric capacitor and a resistor to directly measure the ferroelectric negative capacitance during switching. A time-dependent Ginzburg-Landau approach is used to investigate the underlying domain dynamics. The transien...

  8. Increased levels of dioxin-like substances in adipose tissue in patients with deep infiltrating endometriosis.

    Martínez-Zamora, M A; Mattioli, L; Parera, J; Abad, E; Coloma, J L; van Babel, B; Galceran, M T; Balasch, J; Carmona, F

    2015-05-01

    Are the levels of biologically active and the most toxic dioxin-like substances in adipose tissue of patients with deep infiltrating endometriosis (DIE) higher than in a control group without endometriosis? DIE patients have higher levels of dioxins and polychlorinated biphenyls (PCBs) in adipose tissue compared with controls without endometriosis. Some studies have investigated the levels of dioxin-like substances, in serum samples, in patients with endometriosis, with inconsistent results. Case-control study including two groups of patients. The study group (DIE group) consisted of 30 patients undergoing laparoscopic surgery because of DIE. In all patients, an extensive preoperative work-up was performed including clinical exploration, magnetic resonance imaging (MRI) and transvaginal sonography. All patients with DIE underwent a confirmatory histological study for DIE after surgery. The non-endometriosis control group (control group), included the next consecutive patient undergoing laparoscopic surgery in our center due to adnexal benign gynecological disease (ovarian or tubal procedures other than endometriosis) after each DIE patient, and who did not present any type of endometriosis. During the surgical procedure 1-2 g of adipose tissue from the omentum were obtained. Dioxin-like substances were analyzed in adipose tissue in DIE patients and controls without endometriosis. The total toxic equivalence and concentrations of both dioxins and PCBs were significantly higher in patients with DIE in comparison with the control group (P dioxins (2,3,7,8-tetrachlorodibenzo-p-dioxin [2,3,7,8-TCDD] and 1,2,3,7,8-pentachlorodibenzo-p-dioxin [1,2,3,7,8-PeCDD]) (P dioxins and PCBs widely vary in different countries. Furthermore, the strict eligibility criteria used may preclude generalization of the results to other populations and the surgery-based sampling frame may induce a selection bias. Finally, adipose tissue was obtained only from the omentum, and not from other

  9. Systems analysis approach to the disposal of high-level waste in deep ocean sediments

    Marsily, G. de; Hill, M.D.; Murray, C.N.; Talbert, D.M.; Van Dorp, F.; Webb, G.A.M.

    1980-01-01

    Among the different options being studied for disposal of high-level solidified waste, increasing attention is being paid to that of emplacement of glasses incorporating the radioactivity in deep oceanic sediments. This option has the advantage that the areas of the oceans under investigation appear to be relatively unproductive biologically, are relatively free from cataclysmic events, and are areas in which the natural processes are slow. Thus the environment is stable and predictable so that a number of barriers to the release and dispersion of radioactivity can be defined. Task Groups set up in the framework of the International Seabed Working Group have been studying many aspects of this option since 1976. In order that the various parts of the problem can be assessed within an integrated framework, the methods of systems analysis have been applied. In this paper the Systems Analysis Task Group members report the development of an overall system model. This will be used in an iterative process in which a preliminary analysis, together with a sensitivity analysis, identifies the parameters and data of most importance. The work of the other task groups will then be focussed on these parameters and data requirements so that improved results can be fed back into an improved overall systems model. The major requirements for the development of a preliminary overall systems model are that the problem should be separated into identified elements and that the interfaces between the elements should be clearly defined. The model evolved is deterministic and defines the problem elements needed to estimate doses to man

  10. Numerical investigation of high level nuclear waste disposal in deep anisotropic geologic repositories

    Salama, Amgad

    2015-11-01

    One of the techniques that have been proposed to dispose high level nuclear waste (HLW) has been to bury them in deep geologic formations, which offer relatively enough space to accommodate the large volume of HLW accumulated over the years since the dawn of nuclear era. Albeit the relatively large number of research works that have been conducted to investigate temperature distribution surrounding waste canisters, they all abide to consider the host formations as homogeneous and isotropic. While this could be the case in some subsurface settings, in most cases, this is not true. In other words, subsurface formations are, in most cases, inherently anisotropic and heterogeneous. In this research, we show that even a slight difference in anisotropy of thermal conductivity of host rock with direction could have interesting effects on temperature fields. We investigate the effect of anisotropy angle (the angle the principal direction of anisotropy is making with the coordinate system) on the temperature field as well as on the maximum temperature attained in different barrier systems. This includes 0°, 30°, 45°, 60°, and 90°in addition to the isotropic case as a reference. We also consider the effect of anisotropy ratio (the ratio between the principal direction anisotropies) on the temperature fields and maximum temperature history. This includes ratios ranging between 1.5 and 4. Interesting patterns of temperature fields and profiles are obtained. It is found that the temperature contours are aligned more towards the principal direction of anisotropy. Furthermore the peak temperature in the buffer zone is found to be larger the smaller the anisotropy angle and vice versa. © 2015 Elsevier Ltd. All rights reserved.

  11. Trade Study of System Level Ranked Radiation Protection Concepts for Deep Space Exploration

    Cerro, Jeffrey A

    2013-01-01

    A strategic focus area for NASA is to pursue the development of technologies which support exploration in space beyond the current inhabited region of low earth orbit. An unresolved issue for crewed deep space exploration involves limiting crew radiation exposure to below acceptable levels, considering both solar particle events and galactic cosmic ray contributions to dosage. Galactic cosmic ray mitigation is not addressed in this paper, but by addressing credible, easily implemented, and mass efficient solutions for the possibility of solar particle events, additional margin is provided that can be used for cosmic ray dose accumulation. As a result, NASA s Advanced Engineering Systems project office initiated this Radiation Storm Shelter design activity. This paper reports on the first year results of an expected 3 year Storm Shelter study effort which will mature concepts and operational scenarios that protect exploration astronauts from solar particle radiation events. Large trade space definition, candidate concept ranking, and a planned demonstration comprised the majority of FY12 activities. A system key performance parameter is minimization of the required increase in mass needed to provide a safe environment. Total system mass along with operational assessments and other defined protection system metrics provide the guiding metrics to proceed with concept developments. After a downselect to four primary methods, the concepts were analyzed for dosage severity and the amount of shielding mass necessary to bring dosage to acceptable values. Besides analytical assessments, subscale models of several concepts and one full scale concept demonstrator were created. FY12 work terminated with a plan to demonstrate test articles of two selected approaches. The process of arriving at these selections and their current envisioned implementation are presented in this paper.

  12. Increased Levels of NF-kB-Dependent Markers in Cancer-Associated Deep Venous Thrombosis.

    Malaponte, Grazia; Signorelli, Salvatore S; Bevelacqua, Valentina; Polesel, Jerry; Taborelli, Martina; Guarneri, Claudio; Fenga, Concettina; Umezawa, Kazou; Libra, Massimo

    2015-01-01

    Several studies highlight the role of inflammatory markers in thrombosis as well as in cancer. However, their combined role in cancer-associated deep vein thrombosis (DVT) and the molecular mechanisms, involved in its pathophysiology, needs further investigations. In the present study, C-reactive protein, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1β), matrix metalloproteases-9 (MMP-9), vascular endothelial growth factor (VEGF), tissue factor (TF), fibrinogen and soluble P-selectin, were analyzed in plasma and in monocyte samples from 385 cancer patients, of whom 64 were concomitantly affected by DVT (+). All these markers were higher in cancer patients DVT+ than in those DVT-. Accordingly, significantly higher NF-kB activity was observed in cancer patients DVT+ than DVT-. Significant correlation between data obtained in plasma and monocyte samples was observed. NF-kB inhibition was associated with decreased levels of all molecules in both cancer DVT+ and DVT-. To further demonstrate the involvement of NF-kB activation by the above mentioned molecules, we treated monocyte derived from healthy donors with a pool of sera from cancer patients with and without DVT. These set of experiments further suggest the significant role played by some molecules, regulated by NF-kB, and detected in cancer patients with DVT. Our data support the notion that NF-kB may be considered as a therapeutic target for cancer patients, especially those complicated by DVT. Treatment with NF-kB inhibitors may represent a possible strategy to prevent or reduce the risk of DVT in cancer patients.

  13. The structural integrity of high level waste containers for deep disposal

    Keer, T.J.; Martindale, N.J.; Haijtink, B.

    1990-01-01

    Most countries with a nuclear power program are developing plans to dispose of high level waste in deep geological repositories. These facilities are typically in the range 500-1000m below ground. Although long term safety analyses mainly rely on the isolation function of the geological barrier, for the medium term (between 500 and 1000 years) a barrier such as a container (overpack) may play an important role. This paper addresses the mechanical/structural behavior of these structures under extreme geological pressures. The work described in the paper was conducted within the COMPAS project (Container Mechanical Performance Assessment) funded by the Commission of the European Communities and the United Kingdom Department of the Environment. The work was aimed at predicting the modes of failure and failure pressures which characterize the heavy, thick walled mild steel containers which might be considered for the disposal of vitrified waste. The work involved a considerable amount of analytical work, using 3-D non-linear finite element techniques, coupled with a large parallel program of experimental work. The experimental work consisted of a number of scale model tests in which the response of the containers was examined under external pressures as high as 120MPa. Extensive strain-gauge instrumentation was used to record the behavior of the models as they were driven to collapse. A number of comparative computer calculations were carried out by organizations from various European countries. Correlations were established between experimental and analytical data and guidelines regarding the choice of suitable software were established. The work concluded with a full 3-D simulation of the behavior of a container under long-term disposal conditions. In this analysis, non-linearities due to geological effects and material/geometry effects in the container were properly accounted for. 6 refs., 9 figs., 4 tabs

  14. The relationship between the deep-level structure in crust and brewing of strong earthquakes in Xingtai area

    Xiao, Lan-Xi; Zhu, Yuan-Qing; Zhang, Shao-Quan; Liu, Xu; Guo, Yu

    1999-11-01

    In this paper, crust medium is treated as Maxwell medium, and crust model includes hard inclusion, soft inclusion, deep-level fault. The stress concentration and its evolution with time are obtained by using three-dimensional finite element method and differential method. The conclusions are draw as follows: (1) The average stress concentration and maximum shear stress concentration caused by non-heterogeneous of crust are very high in hard inclusion and around the deep fault. With the time passing by, the concentration of average stress in the model gradually trends to uniform. At the same time, the concentration of maximum shear stress in hard inclusion increases gradually. This character is favorable to transfer shear strain energy from soft inclusion to hard inclusion. (2) When the upper mantle beneath the inclusion upheave at a certain velocity of 1 cm/a, the changes of average stress concentration with time become complex, and the boundary of the hard and soft inclusion become unconspicuous, but the maximum shear stress concentration increases much more in the hard inclusion with time at a higher velocity. This feature make for transformation of energy from the soft inclusion to the hard inclusion. (3) The changes of average stress concentration and maximum shear stress concentration with time around the deep-level fault result in further accumulation of maximum shear stress concentration and finally cause the deep-level fault instable and accelerated creep along fault direction. (4) The changes of vertical displacement on the surface of the model, which is caused by the accelerated creep of the deep-level fault, is similar to that of the observation data before Xingtai strong earthquake.

  15. Molecular analyses reveal high levels of eukaryotic richness associated with enigmatic deep-sea protists (Komokiacea)

    Lecroq, Beatrice; Gooday, Andrew John; Cedhagen, Tomas

    2009-01-01

    Komokiaceans are testate agglutinated protists, extremely diverse and abundant in the deep sea. About 40 species are described and share the same main morpholog- ical feature: a test consisting of narrow branching tubules forming a complex system. In some species, the interstices between the tubu......Komokiaceans are testate agglutinated protists, extremely diverse and abundant in the deep sea. About 40 species are described and share the same main morpholog- ical feature: a test consisting of narrow branching tubules forming a complex system. In some species, the interstices between...... suggest strongly that komokiaceans, and probably many other large testate protists, provide a habitat structure for a large spectrum of eukaryotes, significantly contributing to maintaining the biodiversity of micro- and meiofaunal communities in the deep sea....

  16. Improved capacitive melting curve measurements

    Sebedash, Alexander; Tuoriniemi, Juha; Pentti, Elias; Salmela, Anssi

    2009-01-01

    Sensitivity of the capacitive method for determining the melting pressure of helium can be enhanced by loading the empty side of the capacitor with helium at a pressure nearly equal to that desired to be measured and by using a relatively thin and flexible membrane in between. This way one can achieve a nanobar resolution at the level of 30 bar, which is two orders of magnitude better than that of the best gauges with vacuum reference. This extends the applicability of melting curve thermometry to lower temperatures and would allow detecting tiny anomalies in the melting pressure, which must be associated with any phenomena contributing to the entropy of the liquid or solid phases. We demonstrated this principle in measurements of the crystallization pressure of isotopic helium mixtures at millikelvin temperatures by using partly solid pure 4 He as the reference substance providing the best possible universal reference pressure. The achieved sensitivity was good enough for melting curve thermometry on mixtures down to 100 μK. Similar system can be used on pure isotopes by virtue of a blocked capillary giving a stable reference condition with liquid slightly below the melting pressure in the reference volume. This was tested with pure 4 He at temperatures 0.08-0.3 K. To avoid spurious heating effects, one must carefully choose and arrange any dielectric materials close to the active capacitor. We observed some 100 pW loading at moderate excitation voltages.

  17. Decreased plasma levels of activated factor VII in patients with deep vein thrombosis

    Schut, A. M.; Meijers, J. C. M.; Lisman-van Leeuwen, Y.; van Montfoort, M. L.; Roest, M.; de Groot, P. G.; Urbanus, R. T.; Coppens, M.; Lisman, T.

    BackgroundThe initiating trigger in the development of deep vein thrombosis (DVT) remains unidentified. It has been suggested that tissue factor (TF)-bearing microparticles play a key role, which indicates a role for the TF pathway in the initiation of DVT. ObjectiveTo assess the role of the TF

  18. Decreased plasma levels of activated factor VII in patients with deep vein thrombosis

    Schut, A. M.; Meijers, J. C M; Lisman- van Leeuwen, Y.; van Montfoort, M. L.; Roest, M.; de Groot, P. G.; Urbanus, R. T.; Coppens, M.; Lisman, T.

    2015-01-01

    Background: The initiating trigger in the development of deep vein thrombosis (DVT) remains unidentified. It has been suggested that tissue factor (TF)-bearing microparticles play a key role, which indicates a role for the TF pathway in the initiation of DVT. Objective: To assess the role of the TF

  19. Decreased plasma levels of activated factor VII in patients with deep vein thrombosis

    Schut, A. M.; Meijers, J. C. M.; Lisman-van Leeuwen, Y.; van Montfoort, M. L.; Roest, M.; de Groot, P. G.; Urbanus, R. T.; Coppens, M.; Lisman, T.

    2015-01-01

    The initiating trigger in the development of deep vein thrombosis (DVT) remains unidentified. It has been suggested that tissue factor (TF)-bearing microparticles play a key role, which indicates a role for the TF pathway in the initiation of DVT. To assess the role of the TF pathway in the

  20. The behaviour of cemented backfill and the surrounding rockmass at western deep levels south mine

    York, G

    1992-11-01

    Full Text Available Cemented backfill is used at Western Deep Mine as local and regional support areas of high stopping width. The in situ performance is reported and compared to laboratory tests. A back analysis was carried out to obtain a more accurate value...

  1. SeaWiFS Deep Blue Aerosol Optical Thickness Monthly Level 3 Climatology Data Gridded at 0.5 Degrees V004

    National Aeronautics and Space Administration — The SeaWiFS Deep Blue Level 3 Monthly Climatology Product contains monthly global climatology gridded (0.5 x 0.5 deg) data derived from SeaWiFS Deep Blue Level 3...

  2. Deep and shallow acceptor levels in solid solutions Pb0.98Sm0.02S

    Hasanov, H.A.; Rahimov, R.Sh.

    2010-01-01

    It is well known that the metal vacancies the energy levels of which take place between permitted energies of valency band, are the main acceptor centers in the led salts and solid solutions on their base. The aim of the given paper is founding of character of acceptor levels in single crystals Pb 0 .98Sm 0 .02S with low concentrations of charge carrier. The deep and shallow acceptor levels are found at investigation of Hall effect in Pb 0 .98Sm 0 .02S solid solution with character of low concentrations of charge carriers in crystals

  3. Summary report of a seminar on geosphere modelling requirements of deep disposal of low and intermediate level radioactive wastes

    Piper, D.; Paige, R.W.; Broyd, T.W.

    1989-02-01

    A seminar on the geosphere modelling requirements of deep disposal of low and intermediate level radioactive wastes was organised by WS Atkins Engineering Sciences as part of Her Majesty's Inspectorate of Pollution's Radioactive Waste Assessment Programme. The objectives of the seminar were to review geosphere modelling capabilities and prioritise, if possible, any requirements for model development. Summaries of the presentations and subsequent discussions are given in this report. (author)

  4. Assessing the Level of Disability, Deep Cervical Flexor Endurance and Fear Avoidance Beliefs in Bankers with Neck Pain

    Deptee Warikoo

    2013-08-01

    Full Text Available Objective: To assess the level of disability, the deep cervical flexor endurance and fear avoidance beliefs (FAB in bankers with neck pain and to find a correlation between disability and deep cervical muscle endurance, FAB and disability, FAB and deep flexor muscle endurance. Methods: It ws an observational study. The Subjects who had neck pain and minimum 5 years’ experience as a Banker participated in the study. Total 100 subjects were selected. All the subjects were assessed for their disability by the neck pain and disability score (NPDI, their deep cervical flexor endurance using Pressure Biofeedback using Cranio-Cervical flexion test (CCFT and Fear Avoidance Belief by using questionnaire( FABQ. Results: It was found that bankers have a moderate level of disability. The results showed an elevated fear avoidance belief with a mean value of FABQ-PA 21.61±4.42 and FABQ-W 37.81± 5.69. The results indicated that a negative correlation was found between NPDI and CCFT (r=0.855. A positive correlation was found between NPDI and FABQ-PA(r=0.337, FABQ-W(r=0.500. In the present study a negative correlation was found between CCFT and FABQ-W(r=0.553, FABQ-PA (0.348 and positive correlation (r=0.540 was found between FABQ-PA and FABQ-W. Conclusion: The present study concluded that there was a significant level of disability and significantly decreased endurance level and increased fear avoidance beliefs (both work and physical activity related among bankers with neck pain. In addition to that there was a significant correlation found between NPDI and CCFT, NPDI and FABQ, CCFT and FABQ, FABQ-W and FABQ-PA.

  5. Resolving the EH6/7 level in 4H-SiC by Laplace-transform deep level transient spectroscopy

    Alfieri, G.; Kimoto, T.

    2013-01-01

    We show that Laplace transform deep level transient spectroscopy (LDLTS) is an effective technique for the separation of the overlapping emission rates of the EH 6 and EH 7 levels, which are known to constitute EH 6/7 , a mid-gap level in n-type 4H-SiC. The analysis of the electron irradiation dose, electric field dependence, and the effects of carbon interstitials injection on the emission rates of EH 6 and EH 7 shows that EH 7 is dominant over EH 6 and confirms that their nature is related to a carbon vacancy.

  6. Vitrification treatment options for disposal of greater-than-Class-C low-level waste in a deep geologic repository

    Fullmer, K.S.; Fish, L.W.; Fischer, D.K.

    1994-11-01

    The Department of Energy (DOE), in keeping with their responsibility under Public Law 99-240, the Low-Level Radioactive Waste Policy Amendments Act of 1985, is investigating several disposal options for greater-than-Class C low-level waste (GTCC LLW), including emplacement in a deep geologic repository. At the present time vitrification, namely borosilicate glass, is the standard waste form assumed for high-level waste accepted into the Civilian Radioactive Waste Management System. This report supports DOE's investigation of the deep geologic disposal option by comparing the vitrification treatments that are able to convert those GTCC LLWs that are inherently migratory into stable waste forms acceptable for disposal in a deep geologic repository. Eight vitrification treatments that utilize glass, glass ceramic, or basalt waste form matrices are identified. Six of these are discussed in detail, stating the advantages and limitations of each relative to their ability to immobilize GTCC LLW. The report concludes that the waste form most likely to provide the best composite of performance characteristics for GTCC process waste is Iron Enriched Basalt 4 (IEB4)

  7. Considerations affecting deep-well disposal of tritium-bearing low-level aqueous waste from nuclear fuel reprocessing plants

    Trevorrow, L.E.; Warner, D.L.; Steindler, M.J.

    1977-03-01

    Present concepts of disposal of low-level aqueous wastes (LLAW) that contain much of the fission-product tritium from light water reactors involve dispersal to the atmosphere or to surface streams at fuel reprocessing plants. These concepts have been challenged in recent years. Deep-well injection of low-level aqueous wastes, an alternative to biospheric dispersal, is the subject of this presentation. Many factors must be considered in assessing its feasibility, including technology, costs, environmental impact, legal and regulatory constraints, and siting. Examination of these factors indicates that the technology of deep-well injection, extensively developed for other industrial wastes, would require little innovation before application to low-level aqueous wastes. Costs would be low, of the order of magnitude of 10 -4 mill/kWh. The environmental impact of normal deep-well disposal would be small, compared with dispersal to the atmosphere or to surface streams; abnormal operation would not be expected to produce catastrophic results. Geologically suitable sites are abundant in the U.S., but a well would best be co-located with the fuel-reprocessing plant where the LLAW is produced. Legal and regulatory constraints now being developed will be the most important determinants of the feasibility of applying the method

  8. Deep levels in metamorphic InAs/InGaAs quantum dot structures with different composition of the embedding layers

    Golovynskyi, S.; Datsenko, O.; Seravalli, L.; Kozak, O.; Trevisi, G.; Frigeri, P.; Babichuk, I. S.; Golovynska, I.; Qu, Junle

    2017-12-01

    Deep levels in metamorphic InAs/In x Ga1-x As quantum dot (QD) structures are studied with deep level thermally stimulated conductivity (TSC), photoconductivity (PC) and photoluminescence (PL) spectroscopy and compared with data from pseudomorphic InGaAs/GaAs QDs investigated previously by the same techniques. We have found that for a low content of indium (x = 0.15) the trap density in the plane of self-assembled QDs is comparable or less than the one for InGaAs/GaAs QDs. However, the trap density increases with x, resulting in a rise of the defect photoresponse in PC and TSC spectra as well as a reduction of the QD PL intensity. The activation energies of the deep levels and some traps correspond to known defect complexes EL2, EL6, EL7, EL9, and EL10 inherent in GaAs, and three traps are attributed to the extended defects, located in InGaAs embedding layers. The rest of them have been found as concentrated mainly close to QDs, as their density in the deeper InGaAs buffers is much lower. This an important result for the development of light-emitting and light-sensitive devices based on metamorphic InAs QDs, as it is a strong indication that the defect density is not higher than in pseudomorphic InAs QDs.

  9. Bioenergetics of mammalian sperm capacitation.

    Ferramosca, Alessandra; Zara, Vincenzo

    2014-01-01

    After ejaculation, the mammalian male gamete must undergo the capacitation process, which is a prerequisite for egg fertilization. The bioenergetics of sperm capacitation is poorly understood despite its fundamental role in sustaining the biochemical and molecular events occurring during gamete activation. Glycolysis and mitochondrial oxidative phosphorylation (OXPHOS) are the two major metabolic pathways producing ATP which is the primary source of energy for spermatozoa. Since recent data suggest that spermatozoa have the ability to use different metabolic substrates, the main aim of this work is to present a broad overview of the current knowledge on the energy-producing metabolic pathways operating inside sperm mitochondria during capacitation in different mammalian species. Metabolism of glucose and of other energetic substrates, such as pyruvate, lactate, and citrate, is critically analyzed. Such knowledge, besides its obvious importance for basic science, could eventually translate into the development of novel strategies for treatment of male infertility, artificial reproduction, and sperm selection methods.

  10. Dual deep modeling: multi-level modeling with dual potencies and its formalization in F-Logic.

    Neumayr, Bernd; Schuetz, Christoph G; Jeusfeld, Manfred A; Schrefl, Michael

    2018-01-01

    An enterprise database contains a global, integrated, and consistent representation of a company's data. Multi-level modeling facilitates the definition and maintenance of such an integrated conceptual data model in a dynamic environment of changing data requirements of diverse applications. Multi-level models transcend the traditional separation of class and object with clabjects as the central modeling primitive, which allows for a more flexible and natural representation of many real-world use cases. In deep instantiation, the number of instantiation levels of a clabject or property is indicated by a single potency. Dual deep modeling (DDM) differentiates between source potency and target potency of a property or association and supports the flexible instantiation and refinement of the property by statements connecting clabjects at different modeling levels. DDM comes with multiple generalization of clabjects, subsetting/specialization of properties, and multi-level cardinality constraints. Examples are presented using a UML-style notation for DDM together with UML class and object diagrams for the representation of two-level user views derived from the multi-level model. Syntax and semantics of DDM are formalized and implemented in F-Logic, supporting the modeler with integrity checks and rich query facilities.

  11. Capacitance-voltage investigation of silicon photodiodes damaged by MeV energy light ions

    Kalinka, G.; Simon, A.; Novak, M.; Kiss, A.Z.

    2006-01-01

    Complete text of publication follows. Nuclear radiation creates not only deep centers, but in addition influences shallow dopant concentration in semiconductors, as well. At a given temperature the maximum frequency a center can respond to depends on its energy level, therefore the capacitance-voltage (C-V) characteristics of radiation damaged semiconductor diodes should ideally be measured as function of frequency in order to obtain the physical and energy depth distribution of ionized centers [1,2]. In our experiments C-V plots of MeV energy ion irradiated photodiodes were taken at fixed 1 kHz frequency, which is low enough to be sensitive at room temperature to some of the deep levels expected. During, for example, an irradiation with 5.5 MeV α particles the capacitance of a p + nn + diode increased significantly at low voltages, but showed rather small changes at higher ones. The former turned out to be merely related to a decrease of the built in voltage, corresponding to a lifetime to relaxation type transition of the semiconductor [3]. Rescaling C-V data for this change, the remaining, actual capacitance changes could be interpreted as related to nuclear recoil caused damage located around the end of particle tracks. C-V technique has also been used for follow up investigation of spontaneous self annealing at room temperature of irradiated samples. This is shown here by plotting capacitance data normalized to their virgin values as function of depletion depth for irradiation with 430 keV protons, whose range is about 5 μm. The sensitivity of the method is illustrated for low fluence of 6.5 MeV oxygen, whose range is 5 μm, too, and where the normalization is now made to data taken one week after the irradiation. Acknowledgement This work was supported by the Hungarian Research and Technology Innovation Fund and the Croatian Ministry of Science, Education and Sports within the framework of the Hungarian-Croatian Intergovernmental Science and Technology Co

  12. Production-Level Facial Performance Capture Using Deep Convolutional Neural Networks

    Laine, Samuli; Karras, Tero; Aila, Timo; Herva, Antti; Saito, Shunsuke; Yu, Ronald; Li, Hao; Lehtinen, Jaakko

    2016-01-01

    We present a real-time deep learning framework for video-based facial performance capture -- the dense 3D tracking of an actor's face given a monocular video. Our pipeline begins with accurately capturing a subject using a high-end production facial capture pipeline based on multi-view stereo tracking and artist-enhanced animations. With 5-10 minutes of captured footage, we train a convolutional neural network to produce high-quality output, including self-occluded regions, from a monocular v...

  13. Voltage Dependence of Supercapacitor Capacitance

    Szewczyk Arkadiusz

    2016-09-01

    Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.

  14. Exploring the Deep-Level Reasoning Questions Effect during Vicarious Learning among Eighth to Eleventh Graders in the Domains of Computer Literacy and Newtonian Physics

    Gholson, Barry; Witherspoon, Amy; Morgan, Brent; Brittingham, Joshua K.; Coles, Robert; Graesser, Arthur C.; Sullins, Jeremiah; Craig, Scotty D.

    2009-01-01

    This paper tested the deep-level reasoning questions effect in the domains of computer literacy between eighth and tenth graders and Newtonian physics for ninth and eleventh graders. This effect claims that learning is facilitated when the materials are organized around questions that invite deep-reasoning. The literature indicates that vicarious…

  15. AlxGa1--xN/GaN band offsets determined by deep-level emission

    Hang, D. R.; Chen, C. H.; Chen, Y. F.; Jiang, H. X.; Lin, J. Y.

    2001-01-01

    We present studies of the compositional dependence of the optical properties of Al x Ga 1-x N(0 x Ga 1-x N. As aluminum concentration increases, the color of the band changes from yellow (2.2 eV) to blue (2.6 eV). The shift was less than that of the band gap. Together with previously published studies, it implies that the deep acceptor level is pinned to a common reference level to both materials, thus the deep level responsible for the yellow emission is used as a common reference level to determine the band alignment in Al x Ga 1-x N/GaN heterojunctions. Combining with the near-band-edge modulation spectra, the estimated ratio of conduction-to-valence band discontinuity is 65:35. Our results are close to the values obtained from PL measurements on Al 0.14 Ga 0.86 N/GaN quantum wells and those calculated by linear muffin-tin orbital method and linearized augmented plane wave method. copyright 2001 American Institute of Physics

  16. Guidelines for the operation and closure of deep geological repositories for the disposal of high level and alpha bearing wastes

    1991-10-01

    The operation and closure of a deep geological repository for the disposal of high level and alpha bearing wastes is a long term project involving many disciplines. This unique combination of nuclear operations in a deep underground location will require careful planning by the operating organization. The basic purpose of the operation stage of the deep repository is to ensure the safe disposal of the radioactive wastes. The purpose of the closure stage is to ensure that the wastes are safely isolated from the biosphere, and that the surface region can be returned to normal use. During these two stages of operation and closure, it is essential that both workers and the public are safely protected from radiation hazards, and that workers are protected from the hazards of working underground. For these periods of the repository, it is essential to carry out monitoring for purposes of radiological protection, and to continue testing and investigations to provide data for repository performance confirmation and for final safety assessment. Over the lengthy stages of operation and closure, there will be substantial feedback of experience and generation of site data. These will lead both to improved quality of operation and a better understanding of the site characteristics, thereby enhancing the confidence in the ability of the repository system to isolate the waste and protect future generations. 15 refs

  17. Deep level transient spectroscopic analysis of p/n junction implanted with boron in n-type silicon substrate

    Wakimoto, Hiroki; Nakazawa, Haruo; Matsumoto, Takashi; Nabetani, Yoichi

    2018-04-01

    For P-i-N diodes implanted and activated with boron ions into a highly-resistive n-type Si substrate, it is found that there is a large difference in the leakage current between relatively low temperature furnace annealing (FA) and high temperature laser annealing (LA) for activation of the p-layer. Since electron trap levels in the n-type Si substrate is supposed to be affected, we report on Deep Level Transient Spectroscopy (DLTS) measurement results investigating what kinds of trap levels are formed. As a result, three kinds of electron trap levels are confirmed in the region of 1-4 μm from the p-n junction. Each DLTS peak intensity of the LA sample is smaller than that of the FA sample. In particular, with respect to the trap level which is the closest to the silicon band gap center most affecting the reverse leakage current, it was not detected in LA. It is considered that the electron trap levels are decreased due to the thermal energy of LA. On the other hand, four kinds of trap levels are confirmed in the region of 38-44 μm from the p-n junction and the DLTS peak intensities of FA and LA are almost the same, considering that the thermal energy of LA has not reached this area. The large difference between the reverse leakage current of FA and LA is considered to be affected by the deep trap level estimated to be the interstitial boron.

  18. Determination of deep-level impurities and their effects on the small-single and LF noise properties of ion-implanted GaAs MESFETs

    Sriram, S.; Kim, B.; Ghosh, P.K.; Das, M.B.; Pennsylvania State Univ., University Park; Pennsylvania State Univ., University Park

    1982-01-01

    A large number of deep levels, with energies ranging from Esub(c)-0.19eV to Esub(c)-0.9eV, have been identified and characterized using ion-implanted MESFET's on undoped and Cr-doped LEC-grown semi-insulating GaAs substrates. Measurement techniques used include deep level transient (DLTS) and steady state spectroscopic (DLSS) methods. Large capture cross-section values are obtained for levels below Esub(c)-0.5eV, possibly due to high electric field. Spectral densities of LF noise with distinct bulges have been shown to be related to deep levels. In some samples, natural deep level related oscillations have been observed and their ionization energies have been determined. (author)

  19. Feasibility of high level radioactive waste disposal in deep sea sediments

    Buckley, D.E.

    1987-01-01

    For the past ten years, an international program has been conducted to investigate the concept feasibility for disposing of spent nuclear fuel waste in deep ocean sediments. These studies by the Seabed Working Group were coordinated by the Nuclear Energy Agency of the Organization for Economic Cooperation and Development. Penetrators have been considered as the primary method of waste emplacement. This required emphasis on studies of the nature of the plastic sediments which would form the primary barrier to the release of radionuclides into the biosphere. Site qualification guidelines, included criteria for tectonic and sedimentary stability over periods of at least 10 5 years. Using these guidelines two potential areas were identified: one in the Madeira Abyssal Plain; and one in the Southern Nares Abyssal Plain, both in the North Atlantic

  20. Studies on the deep-level defects in CdZnTe crystals grown by travelling heater method

    Zhou, Boru; Jie, Wanqi; Wang, Tao; Xu, Lingyan; Yang, Fan; Yin, Liying; Fu, Xu [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an (China); Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi (China); Nan, Ruihua [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an (China); Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices, School of Materials and Chemical Engineering, Xi' an Technological University, Xi' an (China)

    2017-05-15

    The variation of deep level defects along the axis of CZT:In ingots grown by Travelling Heater Method was investigated by the means of thermally stimulated current (TSC) spectra. Models for the reaction among different defects In, Te{sub i}, and V{sub Cd} were used to analyze the variation of deep level defects along the growth direction. It was found that the density of In dopant-related defects is lower in the tip, but those of Te antisites and Te interstitials are higher in the tip. The density of cadmium vacancy exhibits an initial increase followed by a decrease from the tip to tail of the ingot. In PL spectra, the intensities of (D{sub 0}, X), (DAP) and D{sub complex} peaks obviously increase from the tip to the tail, due to the increase of the density of In dopant-related defects (IN{sup +}{sub CD}), Cd vacancies, and impurities. The low concentration of net free holes was found by Hall measurements, and high resistivity with p-type conduction was demonstrated from I-V analysis. The mobility for electrons was found to increase significantly from 634 ± 26 cm{sup 2} V{sup -1} s{sup -1} in the tip to 860 ± 10 cm{sup 2} V{sup -1} s{sup -1} in the tail, due to the decrease of the deep level defect densities. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Behavior of deep level defects on voltage-induced stress of Cu(In,Ga)Se{sub 2} solar cells

    Lee, D.W.; Cho, S.E. [Department of Physics and Semiconductor Science, Dongguk University, Seoul (Korea, Republic of); Jeong, J.H. [Solar Cell Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Cho, H.Y., E-mail: hycho@dongguk.edu [Department of Physics and Semiconductor Science, Dongguk University, Seoul (Korea, Republic of)

    2015-05-01

    The behavior of deep level defects by a voltage-induced stress for CuInGaSe{sub 2} (CIGS) solar cells has been investigated. CIGS solar cells were used with standard structures which are Al-doped ZnO/i-ZnO/CdS/CIGSe{sub 2}/Mo on soda lime glass, and that resulted in conversion efficiencies as high as 16%. The samples with the same structure were isothermally stressed at 100 °C under the reverse voltages. The voltage-induced stressing in CIGS samples causes a decrease in the carrier density and conversion efficiency. To investigate the behavior of deep level defects in the stressed CIGS cells, photo-induced current transient spectroscopy was utilized, and normally 3 deep level defects (including 2 hole traps and 1 electron trap) were found to be located at 0.18 eV and 0.29 eV above the valence band maximum (and 0.36 eV below the conduction band). In voltage-induced cells, especially, it was found that the decrease of the hole carrier density could be responsible for the increase of the 0.29 eV defect, which is known to be observed in less efficient CIGS solar cells. And the carrier density and the defects are reversible at least to a large extent by resting at room-temperature without the bias voltage. From optical capture kinetics in photo-induced current transient spectroscopy measurement, the types of defects could be distinguished into the isolated point defect and the extended defect. In this work, it is suggested that the increase of the 0.29 eV defect by voltage-induced stress could be due to electrical activation accompanied by a loss of positive ion species and the activated defect gives rise to reduction of the carrier density. - Highlights: • We investigated behavior of deep level defects by voltage-induced stress. • Defect generation could affect the decrease of the conversion efficiency of cells. • Defect generation could be electrically activated by a loss of positive ion species. • Type of defects could be studied with models of point defects

  2. Inversion of Qubit Energy Levels in Qubit-Oscillator Circuits in the Deep-Strong-Coupling Regime

    Yoshihara, F.; Fuse, T.; Ao, Z.; Ashhab, S.; Kakuyanagi, K.; Saito, S.; Aoki, T.; Koshino, K.; Semba, K.

    2018-05-01

    We report on experimentally measured light shifts of superconducting flux qubits deep-strongly coupled to L C oscillators, where the coupling constants are comparable to the qubit and oscillator resonance frequencies. By using two-tone spectroscopy, the energies of the six lowest levels of each circuit are determined. We find huge Lamb shifts that exceed 90% of the bare qubit frequencies and inversions of the qubits' ground and excited states when there are a finite number of photons in the oscillator. Our experimental results agree with theoretical predictions based on the quantum Rabi model.

  3. Study on deep levels in near-surface region of Hgsub(1-x)Cdsub(x)Te semiconductor

    Antonov, V.V.; Vojtsekhovskij, A.V.; Kazak, E.P.; Lanskaya, O.G.; Pakhorukov, V.A.

    1983-01-01

    Experimental investigation into MOS-structures on the basis of narrow-band n-Hgsub(1-x)Cdsub(X)Te semiconductor was conducted. Anode-oxide film, grown in 0.1N KOH solution in ethylenglycol was used as dielectric laer, olt-farad characteristics of the MOS- structures, measured, at different frequencies of test voltage, testify to the presence of deep monoenergetic levels (Esub(t)) in near surface region of semicondUctor located within the limits of the energy gap of Hgsub(1-x)Cdsub(x)Te. Two types of levels are observed in the n-Hgsub(1-x)Cdsub(x)Te-base MOS-structures at x approximately equal to 0.21: Isub(t)=0.105-0.096 eV and Esub(t)=0.045-0.042 eV (with respect to the valent zone ceiling). The frequency dependence of the equivalent parallel conductivity of the Hgsub(1-x)Cdsub(x)Te-base MOS-structure different voltages on a field electrode was used to show, that the observed deep level has the bulk nature. Results of numeral estimations of the state densities on the impurity center and of capture cross-section of a positive charge (deltasub(p)=6.7x10 -17 -1.4x10 -16 )sm 2 ) are given

  4. Triboelectricity in capacitive biopotential measurements.

    Wartzek, Tobias; Lammersen, Thomas; Eilebrecht, Benjamin; Walter, Marian; Leonhardt, Steffen

    2011-05-01

    Capacitive biopotential measurements suffer from strong motion artifacts, which may result in long time periods during which a reliable measurement is not possible. This study examines contact electrification and triboelectricity as possible reasons for these artifacts and discusses local triboelectric effects on the electrode-body interface as well as global electrostatic effects as common-mode interferences. It will be shown that most probably the triboelectric effects on the electrode-body interface are the main reason for artifacts, and a reduction of artifacts can only be achieved with a proper design of the electrode-body interface. For a deeper understanding of the observed effects, a mathematical model for triboelectric effects in highly isolated capacitive biopotential measurements is presented and verified with experiments. Based on these analyses of the triboelectric effects on the electrode-body interface, different electrode designs are developed and analyzed in order to minimize artifacts due to triboelectricity on the electrode-body interface. © 2011 IEEE

  5. Mapping vaccinia virus DNA replication origins at nucleotide level by deep sequencing.

    Senkevich, Tatiana G; Bruno, Daniel; Martens, Craig; Porcella, Stephen F; Wolf, Yuri I; Moss, Bernard

    2015-09-01

    Poxviruses reproduce in the host cytoplasm and encode most or all of the enzymes and factors needed for expression and synthesis of their double-stranded DNA genomes. Nevertheless, the mode of poxvirus DNA replication and the nature and location of the replication origins remain unknown. A current but unsubstantiated model posits only leading strand synthesis starting at a nick near one covalently closed end of the genome and continuing around the other end to generate a concatemer that is subsequently resolved into unit genomes. The existence of specific origins has been questioned because any plasmid can replicate in cells infected by vaccinia virus (VACV), the prototype poxvirus. We applied directional deep sequencing of short single-stranded DNA fragments enriched for RNA-primed nascent strands isolated from the cytoplasm of VACV-infected cells to pinpoint replication origins. The origins were identified as the switching points of the fragment directions, which correspond to the transition from continuous to discontinuous DNA synthesis. Origins containing a prominent initiation point mapped to a sequence within the hairpin loop at one end of the VACV genome and to the same sequence within the concatemeric junction of replication intermediates. These findings support a model for poxvirus genome replication that involves leading and lagging strand synthesis and is consistent with the requirements for primase and ligase activities as well as earlier electron microscopic and biochemical studies implicating a replication origin at the end of the VACV genome.

  6. Feasibility of high level radioactive waste disposal in deep sea sediments

    Buckley, D.E.

    1987-01-01

    For the past ten years, an international program has been conducted to investigate the concept feasibility for disposing of spent nuclear fuel waste in deep ocean sediments. These studies by the Seabed Working Group were coordinated by the Nuclear Energy Agency of the Organization for Economic Cooperation and Development. Penetrators have been considered as the primary method of waste emplacement. This required emphasis on studies of the nature of the plastic sediments which would form the primary barrier to the release of radionuclides into the biosphere. Site qualification guidelines, included criteria for tectonic and sedimentary stability over periods of at least 10 5 years. Using these guidelines two potential areas were identified: one in the Madeira Abyssal Plain; and one in the Southern Nares Abyssal Plain, both in the North Atlantic. The sediment barrier properties are quite different in terms of dominant mineralogy (carbonates in MAP, and silicous clays in SNAP). The MAP is dominated by thick wide-spread turbidites, but SNAP is dominated by thin discontinuous turbidites

  7. Growth temperature and dopant species effects on deep levels in Si grown by low temperature molecular beam epitaxy

    Chung, Sung-Yong; Jin, Niu; Rice, Anthony T.; Berger, Paul R.; Yu, Ronghua; Fang, Z-Q.; Thompson, Phillip E.

    2003-01-01

    Deep-level transient spectroscopy measurements were performed in order to investigate the effects of substrate growth temperature and dopant species on deep levels in Si layers during low-temperature molecular beam epitaxial growth. The structures studied were n + -p junctions using B doping for the p layer and p + -n junctions using P doping for the n layer. While the density of hole traps H1 (0.38-0.41 eV) in the B-doped p layers showed a clear increase with decreasing growth temperature from 600 to 370 degree sign C, the electron trap density was relatively constant. Interestingly, the minority carrier electron traps E1 (0.42-0.45 eV) and E2 (0.257 eV), found in the B-doped p layers, are similar to the majority carrier electron traps E11 (0.48 eV) and E22 (0.269 eV) observed in P-doped n layers grown at 600 degree sign C. It is hypothesized that these dominating electron traps are associated with pure divacancy defects and are independent of the dopant species

  8. Radiation-induced bistable centers with deep levels in silicon n{sup +}–p structures

    Lastovskii, S. B., E-mail: lastov@ifttp.bas-net.by [Scientific and Practical Materials Research Center of the National Academy of Sciences of Belarus (Belarus); Markevich, V. P. [Manchester University, Photon Science Institute (United Kingdom); Yakushevich, H. S.; Murin, L. I. [Scientific and Practical Materials Research Center of the National Academy of Sciences of Belarus (Belarus); Krylov, V. P. [Vladimir State University (Russian Federation)

    2016-06-15

    The method of deep level transient spectroscopy is used to study electrically active defects in p-type silicon crystals irradiated with MeV electrons and α particles. A new radiation-induced defect with the properties of bistable centers is determined and studied. After keeping the irradiated samples at room temperature for a long time or after their short-time annealing at T ∼ 370 K, this defect does not display any electrical activity in p-type silicon. However, as a result of the subsequent injection of minority charge carriers, this center transforms into the metastable configuration with deep levels located at E{sub V} + 0.45 and E{sub V} + 0.54 eV. The reverse transition to the main configuration occurs in the temperature range of 50–100°C and is characterized by the activation energy ∼1.25 eV and a frequency factor of ∼5 × 10{sup 15} s{sup –1}. The determined defect is thermally stable at temperatures as high as T ∼ 450 K. It is assumed that this defect can either be a complex of an intrinsic interstitial silicon atom with an interstitial carbon atom or a complex consisting of an intrinsic interstitial silicon atom with an interstitial boron atom.

  9. Decomposition of groundwater level fluctuations using transfer modelling in an area with shallow to deep unsaturated zones

    Gehrels, J. C.; van Geer, F. C.; de Vries, J. J.

    1994-05-01

    Time series analysis of the fluctuations in shallow groundwater levels in the Netherlands lowlands have revealed a large-scale decline in head during recent decades as a result of an increase in land drainage and groundwater withdrawal. The situation is more ambiguous in large groundwater bodies located in the eastern part of the country, where the unsaturated zone increases from near zero along the edges to about 40 m in the centre of the area. As depth of the unsaturated zone increases, groundwater level reacts with an increasing delay to fluctuations in climate and influences of human activities. The aim of the present paper is to model groundwater level fluctuations in these areas using a linear stochastic transfer function model, relating groundwater levels to estimated precipitation excess, and to separate artificial components from the natural groundwater regime. In this way, the impact of groundwater withdrawal and the reclamation of a 1000 km 2 polder area on the groundwater levels in the adjoining higher ground could be assessed. It became evident that the linearity assumption of the transfer functions becomes a serious drawback in areas with the deepest groundwater levels, because of non-linear processes in the deep unsaturated zone and the non-synchronous arrival of recharge in the saturated zone. Comparison of the results from modelling the influence of reclamation with an analytical solution showed that the lowering of groundwater level is partly compensated by reduced discharge and therefore is less than expected.

  10. Deep levels in SiC:V by high temperature transport measurements

    Mitchel, W.C.; Perrin, R.; Goldstein, J.; Roth, M.; Ahoujja, M.; Smith, S.R.; Solomon, J.S.; Landis, G.; Jenny, J. [Air Force Materials Lab., Wright-Patterson AFB, OH (United States). Research and Technology Div.; Evwaraye, A.O. [Univ. of Dayton, Dayton, OH (United States); Hobgood, H.McD.; Augustine, G.; Balakrishna, V. [Northrop Grumman Corp., Science and Technology Center, Pittsburgh, PA (United States)

    1998-06-01

    Vanadium doped 6H and 4H SiC have been studied with high temperature Hall effect and resistivity, optical absorption and SIMS. The 6H samples were found to exhibit three thermal activation energies, 0.35 eV, 0.7 eV and near mid-gap. The 0.3 eV level is due to thermal ionization of residual uncompensated boron. We attribute the mid-gap level to thermal ionization of the vanadium donor level. The 0.7 eV activation is believed to be due to transfer of electrons from the ionized vanadium acceptor levels to the conduction band. These results suggest that the vanadium donor and acceptor levels are located at E{sub c}-1.42 eV and E{sub V} + 2.4 eV respectively. (orig.) 7 refs.

  11. Effect of antimony on the deep-level traps in GaInNAsSb thin films

    Islam, Muhammad Monirul, E-mail: islam.monir.ke@u.tsukuba.ac.jp; Miyashita, Naoya; Ahsan, Nazmul; Okada, Yoshitaka [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro ku, Tokyo 153-8904 (Japan); Sakurai, Takeaki; Akimoto, Katsuhiro [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)

    2014-09-15

    Admittance spectroscopy has been performed to investigate the effect of antimony (Sb) on GaInNAs material in relation to the deep-level defects in this material. Two electron traps, E1 and E2 at an energy level 0.12 and 0.41 eV below the conduction band (E{sub C}), respectively, were found in undoped GaInNAs. Bias-voltage dependent admittance confirmed that E1 is an interface-type defect being spatially localized at the GaInNAs/GaAs interface, while E2 is a bulk-type defect located around mid-gap of GaInNAs layer. Introduction of Sb improved the material quality which was evident from the reduction of both the interface and bulk-type defects.

  12. Basic reasons and the practice of using deep water-bearing levels for liquid radioactive waste disposal

    Spitsyn, V.I.; Pimenov, M.K.; Balukova, V.D.; Leontichuk, A.S.; Kokorin, I.N.; Yudin, F.P.; Rakov, N.A.

    1978-01-01

    Speculations are presented on the development and organization of liquid radioactive waste underground disposal in deep water-bearing levels completely isolated from other levels and the surface. Major requirements are formulated that are laid down to low-, moderate-and high-radioactive wastes subject to the disposal. Geological and hydrological conditions as well as the scheme and design features of pilot field facilities are described, where works on high-active waste disposal were started in 1972. In 1972 and 1973 450 and 1050 m 3 of the wastes (7.5 and 53 MCi) respecrespectively were disposed. The first results of the pilot disposal and the 3-year surveillance over the plate-collector condition and the performance of the facilities have reaffirmed the feasibility, medical and radiation safety and economic attractiveness of the disposal of wastes with up to 10-25 Ci/l specific activity

  13. Deep uncertainty and broad heterogeneity in country-level social cost of carbon

    Ricke, K.; Drouet, L.; Caldeira, K.; Tavoni, M.

    2017-12-01

    The social cost of carbon (SCC) is a commonly employed metric of the expected economic damages expected from carbon dioxide (CO2) emissions. Recent estimates of SCC range from approximately 10/tonne of CO2 to as much as 1000/tCO2, but these have been computed at the global level. While useful in an optimal policy context, a world-level approach obscures the heterogeneous geography of climate damages and vast differences in country-level contributions to global SCC, as well as climate and socio-economic uncertainties, which are much larger at the regional level. For the first time, we estimate country-level contributions to SCC using recent climate and carbon-cycle model projections, empirical climate-driven economic damage estimations, and information from the Shared Socio-economic Pathways. Central specifications show high global SCC values (median: 417 /tCO2, 66% confidence intervals: 168 - 793 /tCO2) with country-level contributions ranging from -11 (-8 - -14) /tCO2 to 86 (50 - 158) /tCO2. We quantify climate-, scenario- and economic damage- driven uncertainties associated with the calculated values of SCC. We find that while the magnitude of country-level social cost of carbon is highly uncertain, the relative positioning among countries is consistent. Countries incurring large fractions of the global cost include India, China, and the United States. The share of SCC distributed among countries is robust, indicating climate change winners and losers from a geopolitical perspective.

  14. Intrinsic Low Hysteresis Touch Mode Capacitive Pressure Sensor

    Fragiacomo, Giulio; Pedersen, Thomas; Hansen, Ole

    2011-01-01

    Hysteresis has always been one of the main concerns when fabricating touch mode capacitive pressure sensors (TMCPS). This phenomenon can be fought at two different levels: during fabrication or after fabrication with the aid of a dedicated signal conditioning circuit. We will describe...... a microfabrication step that can be introduced in order to reduce drastically the hysteresis of this type of sensors without compromising their sensitivity. Medium-high range (0 to 10 bar absolute pressure) TMCPS with a capacitive signal span of over 100pF and less than 1 % hysteresis in the entire pressure range...

  15. Development of Image Reconstruction Algorithms in electrical Capacitance Tomography

    Fernandez Marron, J. L.; Alberdi Primicia, J.; Barcala Riveira, J. M.

    2007-01-01

    The Electrical Capacitance Tomography (ECT) has not obtained a good development in order to be used at industrial level. That is due first to difficulties in the measurement of very little capacitances (in the range of femto farads) and second to the problem of reconstruction on- line of the images. This problem is due also to the small numbers of electrodes (maximum 16), that made the usual algorithms of reconstruction has many errors. In this work it is described a new purely geometrical method that could be used for this purpose. (Author) 4 refs

  16. Density Functional Theory Calculations of the Quantum Capacitance of Graphene Oxide as a Supercapacitor Electrode.

    Song, Ce; Wang, Jinyan; Meng, Zhaoliang; Hu, Fangyuan; Jian, Xigao

    2018-03-31

    Graphene oxide has become an attractive electrode-material candidate for supercapacitors thanks to its higher specific capacitance compared to graphene. The quantum capacitance makes relative contributions to the specific capacitance, which is considered as the major limitation of graphene electrodes, while the quantum capacitance of graphene oxide is rarely concerned. This study explores the quantum capacitance of graphene oxide, which bears epoxy and hydroxyl groups on its basal plane, by employing density functional theory (DFT) calculations. The results demonstrate that the total density of states near the Fermi level is significantly enhanced by introducing oxygen-containing groups, which is beneficial for the improvement of the quantum capacitance. Moreover, the quantum capacitances of the graphene oxide with different concentrations of these two oxygen-containing groups are compared, revealing that more epoxy and hydroxyl groups result in a higher quantum capacitance. Notably, the hydroxyl concentration has a considerable effect on the capacitive behavior. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Influence of surface states on deep level transient spectroscopy in AlGaN/GaN heterostructure

    Zhu Qing; Ma Xiao-Hua; Chen Wei-Wei; Hou Bin; Zhu Jie-Jie; Zhang Meng; Chen Li-Xiang; Cao Yan-Rong; Hao Yue

    2016-01-01

    Deep level transient spectroscopy (DLTS) as a method to investigate deep traps in AlGaN/GaN heterostructure or high electron mobility transistors (HEMTs) has been widely utilized. The DLTS measurements under different bias conditions are carried out in this paper. Two hole-like traps with active energies of E v + 0.47 eV, and E v + 0.10 eV are observed, which are related to surface states. The electron traps with active energies of E c − 0.56 eV are located in the channel, those with E c − 0.33 eV and E c − 0.88 eV are located in the AlGaN layer. The presence of surface states has a strong influence on the detection of electron traps, especially when the electron traps are low in density. The DLTS signal peak height of the electron trap is reduced and even disappears due to the presence of plentiful surface state. (paper)

  18. Deep-level transient spectroscopy on an amorphous InGaZnO{sub 4} Schottky diode

    Chasin, Adrian, E-mail: adrian.chasin@imec.be; Bhoolokam, Ajay; Nag, Manoj; Genoe, Jan; Heremans, Paul [imec, Kapeldreef 75, 3001 Leuven (Belgium); ESAT, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven (Belgium); Simoen, Eddy [imec, Kapeldreef 75, 3001 Leuven (Belgium); Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, 9000 Gent (Belgium); Gielen, Georges [ESAT, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven (Belgium)

    2014-02-24

    The first direct measurement is reported of the bulk density of deep states in amorphous IGZO (indium-gallium-zinc oxide) semiconductor by means of deep-level transient spectroscopy (DLTS). The device under test is a Schottky diode of amorphous IGZO semiconductor on a palladium (Pd) Schottky-barrier electrode and with a molybdenum (Mo) Ohmic contact at the top. The DLTS technique allows to independently measure the energy and spatial distribution of subgap states in the IGZO thin film. The subgap trap concentration has a double exponential distribution as a function energy, with a value of ∼10{sup 19} cm{sup −3} eV{sup −1} at the conduction band edge and a value of ∼10{sup 17} cm{sup −3} eV{sup −1} at an energy of 0.55 eV below the conduction band. Such spectral distribution, however, is not uniform through the semiconductor film. The spatial distribution of subgap states correlates well with the background doping density distribution in the semiconductor, which increases towards the Ohmic Mo contact, suggesting that these two properties share the same physical origin.

  19. Development of Human-level Decision Making Algorithm for NPPs through Deep Neural Networks : Conceptual Approach

    Kim, Seung Geun; Seong, Poong Hyun

    2017-01-01

    Development of operation support systems and automation systems are closely related to machine learning field. However, since it is hard to achieve human-level delicacy and flexibility for complex tasks with conventional machine learning technologies, only operation support systems with simple purposes were developed and high-level automation related studies were not actively conducted. As one of the efforts for reducing human error in NPPs and technical advance toward automation, the ultimate goal of this research is to develop human-level decision making algorithm for NPPs during emergency situations. The concepts of SL, RL, policy network, value network, and MCTS, which were applied to decision making algorithm for other fields are introduced and combined with nuclear field specifications. Since the research is currently at the conceptual stage, more research is warranted.

  20. An approach to evaluate capacitance, capacitive reactance and resistance of pivoted pads of a thrust bearing

    Prashad, Har

    1992-07-01

    A theoretical approach is developed for determining the capacitance and active resistance between the interacting surfaces of pivoted pads and thrust collar, under different conditions of operation. It is shown that resistance and capacitive reactance of a thrust bearing decrease with the number of pads times the values of these parameters for an individual pad, and that capacitance increases with the number of pads times the capacitance of an individual pad. The analysis presented has a potential to diagnose the behavior of pivoted pad thrust bearings with the angle of tilt and the ratio of film thickness at the leading to trailing edge, by determining the variation of capacitance, resistance, and capacitive reactance.

  1. CAPACITANCE OF SUPERCAPACITORS WITH ELECTRODES BASED ON CARBON NANOCOMPOSITE MATERIAL

    S.L Revo; B.I Rachiy; S Hamamda; T.G Avramenko; K.O Ivanenko

    2012-01-01

    This work presents the results of our research of the structure and practically important characteristics of a nanocomposite material on the basis of nanoporous carbon and thermally exfoliated graphite. This work shows that the use of the abovementioned composition in electrodes for supercapacitors allows to attain the level of their specific electrical capacitance at (155...160) F/g.

  2. Thermally stimulated capacitance in gamma irradiated epitaxial 4H-SiC Schottky barrier diodes

    Vigneshwara Raja, P.; Narasimha Murty, N. V. L.

    2018-04-01

    Deep level defects in 4H-SiC Schottky barrier diodes (SBDs) fabricated on n-type epitaxial 4H-SiC have been identified by thermally stimulated capacitance (TSCAP) spectroscopy prior to and after 60Co-gamma irradiation. The TSCAP measurements on the non-irradiated SBDs reveal two electron traps at Ec-0.63 eV (˜250 K) and Ec-1.13 eV (˜525 K), whereas only one trap at Ec-0.63 eV is identified by conventional thermally stimulated current (TSC) measurements. Hence, TSCAP spectroscopy is more effective in identifying deep level defects in epitaxial 4 H-SiC SBDs as compared to the TSC spectroscopy. Upon exposure to 60Co-gamma rays up to a dose of 100 Mrad, significant changes in the concentration of the traps at Ec-0.63 eV, Ec-1.13 eV, and one new trap at Ec-0.89 eV (˜420 K) are observed. The electrical characteristics of the SBDs are considerably changed after gamma irradiation. The dominant mechanisms responsible for the irradiation induced changes in the SBD electrical characteristics are analyzed by incorporating the trap signatures in the commercial Silvaco® TCAD device simulator. The extracted trap parameters of the irradiated SBDs may be helpful in predicting the survival of 4H-SiC SBD detectors at higher irradiation levels.

  3. Deep layer-resolved core-level shifts in the beryllium surface

    Aldén, Magnus; Skriver, Hans Lomholt; Johansson, Börje

    1993-01-01

    Core-level energy shifts for the beryllium surface region are calculated by means of a Green’s function technique within the tight-binding linear muffin-tin orbitals method. Both initial- and final-state effects in the core-ionization process are fully accounted for. Anomalously large energy shifts...

  4. China's deep geological disposal program for high level radioactive waste, background and status 1998

    Ju Wang; Xu Guoqing; Guo Yonghai

    2001-01-01

    This paper presents the background and progress made in the study of China's high level radioactive waste, including site screening, site evaluation, the study on radionuclide migration, bentonite, natural analogue studies, and performance assessment, etc. The study on Beishan area, the potential area for China's geological repository, is also presented in this paper. (author)

  5. The application of the csamt method in the tectonic transformation of the deep-level fore exploration in the shandongkeng area in Nanxiong basin

    Xu Zhan

    2010-01-01

    With the national policy efforts on the strengthening of mining exploration, uranium exploration has also ushered in its second s pring . The topic of the new round exploration is P rospect the deeply minerals . Therefore, the changes of the deep structure of the mining area are the premise to carry out survey work. This article states briefly the working principle and characteristics of CSAMT method. The Application of the CSAMT Method in the Tectonic Transformation of The Deep-Level Exploration in the Shangdongkeng area in Nanxiong basin expresses that the method has a good application and effectiveness in research of deep geological objectives. It provides design basis for the mining exploration of deep-level area. (authors)

  6. Capacitance enhancement via electrode patterning

    Ho, Tuan A.; Striolo, Alberto

    2013-01-01

    The necessity of increasing the energy density in electric double layer capacitors to meet current demand is fueling fundamental and applied research alike. We report here molecular dynamics simulation results for aqueous electrolytes near model electrodes. Particular focus is on the effect of electrode patterning on the structure of interfacial electrolytes, and on the potential drop between the solid electrodes and the bulk electrolytes. The latter is estimated by numerically integrating the Poisson equation using the charge densities due to water and ions accumulated near the interface as input. We considered uniform and patterned electrodes, both positively and negatively charged. The uniformly charged electrodes are modeled as graphite. The patterned ones are obtained by removing carbon atoms from the top-most graphene layer, yielding nanoscopic squares and stripes patterns. For simplicity, the patterned electrodes are effectively simulated as insulators (the charge remains localized on the top-most layer of carbon atoms). Our simulations show that the patterns alter the structure of water and the accumulation of ions at the liquid-solid interfaces. Using aqueous NaCl solutions, we found that while the capacitance calculated for three positively charged electrodes did not change much, that calculated for the negatively charged electrodes significantly increased upon patterning. We find that both water structure and orientation, as well as ion accumulation affect the capacitance. As electrode patterning affects differently water structure and ion accumulation, it might be possible to observe ion-specific effects. These results could be useful for advancing our understanding of electric double layer capacitors, capacitive desalination processes, as well as of fundamental interfacial electrolytes properties

  7. Sensitivity of on-resistance and threshold voltage to buffer-related deep level defects in AlGaN/GaN high electron mobility transistors

    Armstrong, Andrew M; Allerman, Andrew A; Baca, Albert G; Sanchez, Carlos A

    2013-01-01

    The influence of deep levels defects located in highly resistive GaN:C buffers on the on-resistance (R ON ) and threshold voltage (V th ) of AlGaN/GaN high electron mobility transistors (HEMTs) power devices was studied by a combined photocapacitance deep level optical spectroscopy (C-DLOS) and photoconductance deep level optical spectroscopy (G-DLOS) methodology as a function of electrical stress. Two carbon-related deep levels at 1.8 and 2.85 eV below the conduction band energy minimum were identified from C-DLOS measurements under the gate electrode. It was found that buffer-related defects under the gate shifted V th positively by approximately 10%, corresponding to a net areal density of occupied defects of 8 × 10 12 cm −2 . The effect of on-state drain stress and off-state gate stress on buffer deep level occupancy and R ON was also investigated via G-DLOS. It was found that the same carbon-related deep levels observed under the gate were also active in the access region. Off-state gate stress produced significantly more trapping and degradation of R ON (∼140%) compared to on-state drain stress (∼75%). Greater sensitivity of R ON to gate stress was explained by a more sharply peaked lateral distribution of occupied deep levels between the gate and drain compared to drain stress. The overall greater sensitivity of R ON compared to V th to buffer defects suggests that electron trapping is significantly greater in the access region compared to under the gate, likely due to the larger electric fields in the latter region. (invited paper)

  8. The case for deep-sea disposal of low-level solid radioactive wastes

    Lewis, J.B.

    1983-01-01

    The scientific justification for the sea disposal of low-level solid radioactive wastes is summarized and the relevant national and international codes of practice and legislation are outlined. It is concluded that, since the amount of radioactivity disposed of in the oceans is very small compared with the natural radioactivity, the environmental hazard is small and sea dumping could be increased. (U.K.)

  9. Percoll gradient-centrifuged capacitated mouse sperm have increased fertilizing ability and higher contents of sulfogalactosylglycerolipid and docosahexaenoic acid-containing phosphatidylcholine compared to washed capacitated mouse sperm.

    Furimsky, Anna; Vuong, Ngoc; Xu, Hongbin; Kumarathasan, Premkumari; Xu, Min; Weerachatyanukul, Wattana; Bou Khalil, Maroun; Kates, Morris; Tanphaichitr, Nongnuj

    2005-03-01

    Although Percoll gradient centrifugation has been used routinely to prepare motile human sperm, its use in preparing motile mouse sperm has been limited. Here, we showed that Percoll gradient-centrifuged (PGC) capacitated mouse sperm had markedly higher fertilizing ability (sperm-zona pellucida [ZP] binding and in vitro fertilization) than washed capacitated mouse sperm. We also showed that the lipid profiles of PGC capacitated sperm and washed capacitated sperm differed significantly. The PGC sperm had much lower contents of cholesterol and phospholipids. This resulted in relative enrichment of male germ cell-specific sulfogalactosylglycerolipid (SGG), a ZP-binding ligand, in PGC capacitated sperm, and this would explain, in part, their increased ZP-binding ability compared with that of washed capacitated sperm. Analyses of phospholipid fatty acyl chains revealed that PGC capacitated sperm were enriched in phosphatidylcholine (PC) molecular species containing highly unsaturated fatty acids (HUFAs), with docosahexaenoic acid (DHA; C22: 6n-3) being the predominant HUFA (42% of total hydrocarbon chains of PC). In contrast, the level of PC-HUFAs comprising arachidonic acid (20:4n-6), docosapentaenoic acid (C22:5n-6), and DHA in washed capacitated sperm was only 27%. Having the highest unsaturation degree among all HUFAs in PC, DHA would enhance membrane fluidity to the uppermost. Therefore, membranes of PGC capacitated sperm would undergo fertilization-related fusion events at higher rates than washed capacitated sperm. These results suggested that PGC mouse sperm should be used in fertilization experiments and that SGG and DHA should be considered to be important biomarkers for sperm fertilizing ability.

  10. Disposal of high level and long lived radioactive waste in deep geological formation

    Niezborala, J.M.; Hoorelbeke, J.M.

    2000-01-01

    The status of ANDRA's research program on high level and long lived waste corresponds to the start of construction of the Meuse/Haute-Marne Underground Research Laboratory in an argillite layer, as well as to the selection in 1999 of preliminary disposal concepts corresponding to this layer. The paper describes the preliminary concepts dealing with transuranic waste, high level vitrified waste and potentially disposed spent fuel. Provision is made for a high level of flexibility, in particular with regard to options of reversibility of the disposal process, and to potential evolutions of the waste inventory. These concepts were selected for research purpose to assess by the year 2006 the feasibility of a potential repository, with.respect in particular to safety rules. The paper mentions the research targets of the program aiming at answering major scientific and technological questions raised by the concepts. The program includes the fitting and validation of the modelling, on the basis in particular of the experimental work to be carried out in the Underground Research Laboratory, making it possible to dimension the disposal concepts and to assess their safety. (authors)

  11. Aspheric surface measurement using capacitive probes

    Tao, Xin; Yuan, Daocheng; Li, Shaobo

    2017-02-01

    With the application of aspheres in optical fields, high precision and high efficiency aspheric surface metrology becomes a hot research topic. We describe a novel method of non-contact measurement of aspheric surface with capacitive probe. Taking an eccentric spherical surface as the object of study, the averaging effect of capacitive probe measurement and the influence of tilting the capacitive probe on the measurement results are investigated. By comparing measurement results from simultaneous measurement of the capacitive probe and contact probe of roundness instrument, this paper indicates the feasibility of using capacitive probes to test aspheric surface and proposes the compensation method of measurement error caused by averaging effect and the tilting of the capacitive probe.

  12. A preliminary study on the geochemical environment for deep geological disposal of high level radioactive waste in Korea

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Koh, Yong Kwon; Park, Byoung Yun

    2000-03-01

    Geochemical study on the groundwater from crystalline rocks (granite and gneiss) for the deep geological disposal of high-level radioactive waste was carried out in order to elucidate the hydrogeochemical and isotope characteristics and geochemical evolution of the groundwater. Study areas are Jungwon, Chojeong, Youngcheon and Yusung for granite region, Cheongyang for gneiss region, and Yeosu for volcanic region. Groundwaters of each study areas weree sampled and analysed systematically. Groundwaters can be grouped by their chemistry and host rock. Origin of the groundwater was proposed by isotope ( 18 O, 2 H, 13 C, 34 S, 87 Sr, 15 N) studies and the age of groundwater was inferred from their tritium contents. Based ont the geochemical and isotope characteristics, the geochemical evolutions of each types of groundwater were simulated using SOLVEQ/CHILLER and PHREEQC programs

  13. Decommissioning of surface facilities associated with repositories for the deep geological disposal of high-level nuclear wastes

    Heckman, R.A.

    1978-11-01

    A methodology is presented in this paper to evaluate the decommissioning of the surface facilities associated with repositories for the deep geological disposal of high-level nuclear wastes. A cost/risk index (figure of merit), expressed as $/manrem, is proposed as an evaluation criteria. On the basis of this cost/risk index, we gain insight into the advisability of adapting certain decontamination design options into the original facility. Three modes are considered: protective storage, entombment, and dismantlement. Cost estimates are made for the direct labor involved in each of the alternative modes for a baseline design case. Similarly, occupational radiation exposures are estimated, with a larger degree of uncertainty, for each of the modes. Combination of these estimates produces the cost/risk index. To illustrate the methodology, an example using a preliminary baseline repository design is discussed

  14. Predicted peak temperature-rises around a high-level radioactive waste canister emplaced in the deep ocean bed

    Kipp, K.L.

    1978-06-01

    A simple mathematical model of heat conduction was used to evaluate the peak temperature-rise along the wall of a canister of high-level radioactive waste buried in deep ocean sediment. Three different amounts of vitrified waste, corresponding to standard Harvest, large Harvest, and AVM canisters, and three different waste loadings were studied. Peak temperature-rise was computed for the nine cases as a function of canister geometry and storage time between reprocessing and burial. Lower waste loadings or longer storage times than initially envisaged are necessary to prevent the peak temperature-rise from exceeding 200 0 C. The use of longer, thinner cylinders only modestly reduces the storage time for a given peak temperature. Effects of stacking of waste canisters and of close-packing were also studied. (author)

  15. A preliminary study on the geochemical environment for deep geological disposal of high level radioactive waste in Korea

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Koh, Yong Kwon; Park, Byoung Yun

    2000-03-01

    Geochemical study on the groundwater from crystalline rocks (granite and gneiss) for the deep geological disposal of high-level radioactive waste was carried out in order to elucidate the hydrogeochemical and isotope characteristics and geochemical evolution of the groundwater. Study areas are Jungwon, Chojeong, Youngcheon and Yusung for granite region, Cheongyang for gneiss region, and Yeosu for volcanic region. Groundwaters of each study areas weree sampled and analysed systematically. Groundwaters can be grouped by their chemistry and host rock. Origin of the groundwater was proposed by isotope ({sup 18}O, {sup 2}H, {sup 13}C, {sup 34}S, {sup 87}Sr, {sup 15}N) studies and the age of groundwater was inferred from their tritium contents. Based ont the geochemical and isotope characteristics, the geochemical evolutions of each types of groundwater were simulated using SOLVEQ/CHILLER and PHREEQC programs.

  16. Containers and overpacks for high-level radioactive waste in deep geological disposal. Conditions: French Corrosion Programme

    Crusset, D.; Plas, F.; Santarini, G.

    2003-01-01

    Within the framework of the act of French law dated 31 December, 1991, ANDRA (National Radioactive Waste Management Agency) is responsible for conducting the feasibility study on disposal of reversible and irreversible high-level or long-life radioactive waste in deep geological formations. Consequently, ANDRA is carrying out research on corrosion of the metallic materials envisaged for the possible construction of overpacks for vitrified waste packages or containers for spent nuclear fuel. Low-alloy or unalloyed steels and the passive alloys (Fe-Ni-Cr-Mo) constitute the two families of materials studied and ANDRA has set up a research programme in partnership with other research organisations. The 'broad outlines' of the programme, which includes experimental and modelling operations, are presented. (authors)

  17. A preliminary study on the regional fracture systems for deep geological disposal of high level radioactive waste in Korea

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Koh, Young Kown; Park, Byoung Yoon [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-03-01

    For the deep geological disposal of high-level radioactive waste, it is essential to characterize the fracture system in rock mass which has a potential pathways of nuclide. Currently, none of research results are in classification and detailed properties for the fracture system in Korea. This study aims to classify and describe the regional fracture system in lithological and geotectonical point of view using literature review, shaded relief map, and aeromagnetic survey data. This report contains the following: - Theoretical review of the fracture development mechanism. - Overall fault and fracture map. - Geological description on the distributional characteristics of faults and fractures(zone) in terms of lithological domain and tectonical province. 122 refs., 22 figs., 4 tabs. (Author)

  18. Interactive Sea Level Rise App & Online Viewer Offers Deep Dive Into Climate

    Turrin, M.; Porter, D. F.; Ryan, W. B. F.; Pfirman, S. L.

    2015-12-01

    Climate has captured the attention of the public but its complexity can cause interested individuals to turn to opinion pieces, news articles or blogs for information. These platforms often oversimplify or present heavily interpreted or personalized perspectives. Data interactives are an extremely effective way to explore complex geoscience topics like climate, opening windows of understanding for the user that have previously been closed. Layering data onto maps through programs like GeoMapApp and the Earth Observer App has allowed users to dig directly into science data, but with only limited scaffolding. The interactive 'Polar Explorer: Sea Level Explorer App' provides a richly layered introduction to a range of topics connected to sea level rise. Each map is supported with a pop up and a short audio file of supplementary material, and an information page that includes the data source and links for further reading. This type of learning platform works well for both the formal and informal learning environment. Through science data displayed as map visualizations the user is invited into topics through an introductory question, such as "Why does sea level change?" After clicking on that question the user moves to a second layer of questions exploring the role of the ocean, the atmosphere, the contribution from the world's glaciers, world's ice sheets and other less obvious considerations such as the role of post-glacial rebound, or the mining of groundwater. Each question ends in a data map, or series of maps, that offer opportunities to interact with the topic. Under the role of the ocean 'Internal Ocean Temperature' offers the user a chance to touch to see temperature values spatially over the world's ocean, or to click through a data series starting at the ocean surface and diving to 5000 meters of depth showing how temperature changes with depth. Other sections, like the role of deglaciation of North America, allow the user to click and see change through

  19. Role of waste packages in the safety of a high level waste repository in a deep geological formation

    Bretheau, F.; Lewi, J.

    1990-06-01

    The safety of a radioactive waste disposal facility lays on the three following barriers placed between the radioactive materials and the biosphere: the waste package; the engineered barriers; the geological barrier. The function assigned to each of these barriers in the performance assessment is an option taken by the organization responsible for waste disposal management (ANDRA in France), which must show that: expected performances of each barrier (confinement ability, life-time, etc.) are at least equal to those required to fulfill the assigned function; radiation protection requirements are met in all situations considered as credible, whether they be the normal situation or random event situations. The French waste management strategy is based upon two types of disposal depending on the nature and activity of waste packages: - surface disposal intended for low and medium level wastes having half-lives of about 30 years or less and alpha activity less than 3.7 MBq/kg (0.1 Ci/t), for individual packages and less than 0.37 MBq/kg (0.01 Ci/t) in the average. Deep geological disposal intended for TRU and high level wastes. The conditions of acceptance of packages in a surface disposal site are subject to the two fundamental safety rules no. I.2 and III.2.e. The present paper is only dealing with deep geological disposal. For deep geological repositories, three stages are involved: stage preceding definitive disposal (intermediate storage, transportation, handling, setting up in the disposal cavities); stage subsequent to definitive sealing of the disposal cavities but prior to the end of operation of the repository; stage subsequent to closure of the repository. The role of the geological barrier has been determined as the essential part of long term radioactivity confinement, by a working group, set up by the French safety authorities. Essential technical criteria relating to the choice of a site so defined by this group, are the following: very low permeability

  20. Flexible PVDF ferroelectric capacitive temperature sensor

    Khan, Naveed

    2015-08-02

    In this paper, a capacitive temperature sensor based on polyvinylidene fluoride (PVDF) capacitor is explored. The PVDF capacitor is characterized below its Curie temperature. The capacitance of the PVDF capacitor changes vs temperature with a sensitivity of 16pF/°C. The linearity measurement of the capacitance-temperature relation shows less than 0.7°C error from a best fit straight line. An LC oscillator based temperature sensor is demonstrated based on this capacitor.

  1. Ecological risk assessment of deep geological disposal of high-level nuclear waste

    Hart, D.R.; Lush, D.L.; Acton, D.W.

    1993-01-01

    Contaminant fate and transport models, radiological dosimetry models, chemical dose-response models and population dynamic models were used to estimate ecological risks to moose and brook trout populations arising from a proposed high-level nuclear waste repository. Risks from potential contaminant releases were compared with risks from physical habitat alteration in constructing a repository and service community, and with risks from increased hunting and fish pressure in the area. For a reference environment typical of a proposed location somewhere in the Canadian Shield, preliminary results suggest that the population consequences of contaminant release will be minor relative to those of habitat alteration and natural resource use

  2. Site selection and characterization processes for deep geologic disposal of high level nuclear waste

    Costin, L.S.

    1997-10-01

    In this paper, the major elements of the site selection and characterization processes used in the US high level waste program are discussed. While much of the evolution of the site selection and characterization processes have been driven by the unique nature of the US program, these processes, which are well defined and documented, could be used as an initial basis for developing site screening, selection, and characterization programs in other countries. Thus, this paper focuses more on the process elements than the specific details of the US program

  3. Site selection and characterization processes for deep geologic disposal of high level nuclear waste

    Costin, L.S.

    1997-01-01

    In this paper, the major elements of the site selection and characterization processes used in the U. S. high level waste program are discussed. While much of the evolution of the site selection and characterization processes have been driven by the unique nature of the U. S. program, these processes, which are well-defined and documented, could be used as an initial basis for developing site screening, selection, and characterization programs in other countries. Thus, this paper focuses more on the process elements than the specific details of the U. S. program. (author). 3 refs., 2 tabs., 5 figs

  4. Determination of deep levels in semi-insulating cadmium telluride by thermally stimulated current measurements

    Scharager, C.; Muller, J.C.; Stuck, R.; Siffert, P.

    1975-01-01

    Thermally stimulated current (TSC) measurements have been performed in high resistivity (rho approximately 10 7 ohms.cm) CdTe γ-ray detectors between 35 and 300K. The TSC curves have been analyzed by different methods, including those taking into account the retrapping of the carriers. The trap characteristics have been determined; especially three levels located at E(v)+0.13eV, E(v)+0.30eV and E(c)-0.55eV have been investigated [fr

  5. Site selection and characterization processes for deep geologic disposal of high level nuclear waste

    Costin, L.S. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31

    In this paper, the major elements of the site selection and characterization processes used in the U. S. high level waste program are discussed. While much of the evolution of the site selection and characterization processes have been driven by the unique nature of the U. S. program, these processes, which are well-defined and documented, could be used as an initial basis for developing site screening, selection, and characterization programs in other countries. Thus, this paper focuses more on the process elements than the specific details of the U. S. program. (author). 3 refs., 2 tabs., 5 figs.

  6. Thermal effects on clay rocks for deep disposal of high-level radioactive waste

    Chun-Liang Zhang

    2017-06-01

    Full Text Available Thermal effects on the Callovo-Oxfordian and Opalinus clay rocks for hosting high-level radioactive waste were comprehensively investigated with laboratory and in situ experiments under repository relevant conditions: (1 stresses covering the range from the initial lithostatic state to redistributed levels after excavation, (2 hydraulic drained and undrained boundaries, and (3 heating from ambient temperature up to 90 °C–120 °C and a subsequent cooling phase. The laboratory experiments were performed on normal-sized and large hollow cylindrical samples in various respects of thermal expansion and contraction, thermally-induced pore water pressure, temperature influences on deformation and strength, thermal impacts on swelling, fracture sealing and permeability. The laboratory results obtained from the samples are consistent with the in situ observations during heating experiments in the underground research laboratories at Bure and Mont-Terri. Even though the claystones showed significant responses to thermal loading, no negative effects on their favorable barrier properties were observed.

  7. Leach behavior of high-level borosilicate glasses under deep geological environment

    Kim, Seung Soo; Chun, Kwan Sik; Park, Hyun Soo

    1998-02-01

    This report presents an overview of the activities in high-level radioactive waste glass which is considered as the most practicable form of waste, and also is intended to be used in the disposal of national high-level radioactive waste in future. Leach theory of waste glass and the leach effects of ground water, metal barrier, buffer materials and rocks on the waste glass were reviewed. The leach of waste glass was affected by various factors such as composition, pH and Eh of ground water, temperature, pressure, radiation and humic acid. The crystallization, crack, weathering and the formation of altered phases of waste glass which is expected to occur in real disposal site were reviewed. The results of leaching in laboratory and in-situ were compared. The behaviors of radioactive elements leached from waste glass and the use of basalt glass for the long-term natural analogue of waste glass were also written in this report. The appraisal of durability of borosilicate waste glass as a waste media was performed from the known results of leach test and international in-situ tests were introduced. (author). 134 refs., 15 tabs., 24 figs

  8. Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

    Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

    2016-04-15

    A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

  9. Ultrahigh Temperature Capacitive Pressure Sensor

    Harsh, Kevin

    2014-01-01

    Robust, miniaturized sensing systems are needed to improve performance, increase efficiency, and track system health status and failure modes of advanced propulsion systems. Because microsensors must operate in extremely harsh environments, there are many technical challenges involved in developing reliable systems. In addition to high temperatures and pressures, sensing systems are exposed to oxidation, corrosion, thermal shock, fatigue, fouling, and abrasive wear. In these harsh conditions, sensors must be able to withstand high flow rates, vibration, jet fuel, and exhaust. In order for existing and future aeropropulsion turbine engines to improve safety and reduce cost and emissions while controlling engine instabilities, more accurate and complete sensor information is necessary. High-temperature (300 to 1,350 C) capacitive pressure sensors are of particular interest due to their high measurement bandwidth and inherent suitability for wireless readout schemes. The objective of this project is to develop a capacitive pressure sensor based on silicon carbon nitride (SiCN), a new class of high-temperature ceramic materials, which possesses excellent mechanical and electric properties at temperatures up to 1,600 C.

  10. Dumping of low-level radioactive waste in the deep ocean

    Templeton, W.L.

    1980-01-01

    Two international agreements relate to the dumping of packaged radioactive waste into the oceans - the Convention on the Prevention of Marine Pollution by Dumping Wastes and Other Matter of 1972 (London Convention) and the Multilateral Consultation and Surveillance Mechanism for Sea Dumping of Radioactive Waste of 1977 under the Organization for Economic Co-operation and Development (OECD). The International Atomic Energy Agency was given the responsibility to define high-level radioactive wastes which are unsuitable for dumping in the oceans and to make recommendations for the dumping of other radioactive wastes. A revised Definition and Recommendations was submitted and accepted by the London Convention. This paper reviews the technical basis for the Definition and describes how it has been applied to the radiological assessment of the only operational dumping site in the North East Atlantic

  11. Characterization of deep energy levels in mercury iodide. Application to nuclear detection

    Mohammed Brahim, Tayeb.

    1982-07-01

    The last few years have seen an increasing interest in HgI 2 detectors for room temperature gamma and X-ray spectrometry. Performance and effective thickness of these detectors are presently limited by carrier trapping which results in incomplete charge collection. Characterization of the trapping levels has been performed by several photoelectronic methods (photoconductivity, thermal and optical quenching of the photoconductivity, TSC, lifetime measurement). A model is proposed taking into account the results obtained by these techniques and the polarization phenomena observed in nuclear detection in both vapor phase and solution grown crystals. For the latter, polarization can be eliminated or notably reduced by illumination of the positive electrode or by using a MIS positively biased structure [fr

  12. Greedy Deep Dictionary Learning

    Tariyal, Snigdha; Majumdar, Angshul; Singh, Richa; Vatsa, Mayank

    2016-01-01

    In this work we propose a new deep learning tool called deep dictionary learning. Multi-level dictionaries are learnt in a greedy fashion, one layer at a time. This requires solving a simple (shallow) dictionary learning problem, the solution to this is well known. We apply the proposed technique on some benchmark deep learning datasets. We compare our results with other deep learning tools like stacked autoencoder and deep belief network; and state of the art supervised dictionary learning t...

  13. Chronic Deep Brain Stimulation of the Hypothalamic Nucleus in Wistar Rats Alters Circulatory Levels of Corticosterone and Proinflammatory Cytokines

    Calleja-Castillo, Juan Manuel; De La Cruz-Aguilera, Dora Luz; Manjarrez, Joaquín; Velasco-Velázquez, Marco Antonio; Morales-Espinoza, Gabriel; Moreno-Aguilar, Julia; Hernández, Maria Eugenia; Aguirre-Cruz, Lucinda

    2013-01-01

    Deep brain stimulation (DBS) is a therapeutic option for several diseases, but its effects on HPA axis activity and systemic inflammation are unknown. This study aimed to detect circulatory variations of corticosterone and cytokines levels in Wistar rats, after 21 days of DBS-at the ventrolateral part of the ventromedial hypothalamic nucleus (VMHvl), unilateral cervical vagotomy (UCVgX), or UCVgX plus DBS. We included the respective control (C) and sham (S) groups (n = 6 rats per group). DBS treated rats had higher levels of TNF-α (120%; P < 0.01) and IFN-γ (305%; P < 0.001) but lower corticosterone concentration (48%; P < 0.001) than C and S. UCVgX animals showed increased corticosterone levels (154%; P < 0.001) versus C and S. UCVgX plus DBS increased IL-1β (402%; P < 0.001), IL-6 (160%; P < 0.001), and corsticosterone (178%; P < 0.001 versus 48%; P < 0.001) compared with the C and S groups. Chronic DBS at VMHvl induced a systemic inflammatory response accompanied by a decrease of HPA axis function. UCVgX rats experienced HPA axis hyperactivity as result of vagus nerve injury; however, DBS was unable to block the HPA axis hyperactivity induced by unilateral cervical vagotomy. Further studies are necessary to explore these findings and their clinical implication. PMID:24235973

  14. SPRAYED CLAY TECHNOLOGY FOR THE DEEP REPOSITORY OF HIGH-LEVEL RADIOACTIVE WASTE

    Lucie Hausmannová

    2012-07-01

    Full Text Available The sealing barrier will play very important role in the Czech disposal concept of high level radioactive waste. It follows Swedish SKB3 design where granitic rock environment will host the repository. Swelling clay based materials as the most favorable for sealing purposes were selected. Such clays must fulfill certain requirements (e.g. on swelling properties, hydraulic conductivity or plasticity and must be stable for thousands of years. Better sealing behavior is obtained when the clay is compacted. Technology of the seal construction can vary according to its target dry density. Very high dry density is needed for buffer (sealing around entire canister with radioactive waste. Less strict requirements are on material backfilling the access galleries. It allows compaction to lower dry density than in case of buffer. One of potential technology for backfilling is to compact clay layers in most of the gallery profile by common compaction machines (rollers etc. and to spray clay into the uppermost part afterwards. The paper introduces the research works on sprayed clay technology performed at the Centre of Experimental Geotechnics of the Czech Technical University in Prague. Large scale in situ demonstration of filling of short drift in the Josef Gallery is also mentioned.

  15. EFFECT OF DIESEL CONTAMINATION ON CAPACITANCE VALUES OF CRUDE PALM OIL

    C. H. FIZURA

    2014-06-01

    Full Text Available Measurement of crude palm oil (CPO contamination is a major concern in CPO quality monitoring. In this study, capacitive sensing technique was used to monitor diesel contamination levels in CPO. A low cost capacitive sensing system was developed by using AD7746 capacitance to digital converter. The capacitance value of CPO samples with different contamination levels (v/v% ranged from 0% to 50% was collected at a room temperature (25°C. The objective of this study is to find a relationship between capacitance values and diesel contamination levels in CPO. The results showed that capacitance value decreased as the diesel contamination levels increased. For the 0% to 50% contamination range, the regression equation was y = 0.0002x2 - 0.0125x + 0.936 with R2 value of 0.96. For the 0% to 10% contamination range (where the percentage was the representative of potential contaminations levels found in CPO the correlation equation was y = -0.02x + 0.95 with R2 value of 0.95. These results indicated that capacitive sensing technique has potential for CPO quality monitoring.

  16. Hydrogeologic modelling in support of a proposed Deep Geologic Repository in Canada for low and intermediate level radioactive waste

    Sykes, J.F.; Normani, S.D.; Yin, Y. [Waterloo Univ., ON (Canada). Dept. of Civil and Environmental Engineering; Sykes, E.A.; Jensen, M.R. [Nuclear Waste Management Organization, Toronto, ON (Canada)

    2009-07-01

    Ontario Power Generation (OPG) has proposed the construction of a Deep Geologic Repository (DGR) for low and intermediate level radioactive waste at the Bruce site on the shore of Lake Huron near Tiverton, Ontario. The DGR is to be excavated at a depth of about 680 m within argillaceous limestones of Ordovician age. A saturated regional-scale and site-scale numerical modelling study has been completed in order to evaluate the safety of storing radioactive waste at the site and to better understand the geochemistry and hydrogeology of the formations surrounding the proposed DGR. This paper reported on the regional-scale base-case modelling and analysis of the measured pressure profile in deep boreholes at the DGR site. The numerical modelling study provided a framework to investigate the groundwater flow system as it relates to, and potentially affects, the safety and long-term performance of the DGR. A saturated groundwater flow model was also developed using FRAC3DVS-OPG. The objective of regional-scale groundwater modelling of the Paleozoic sedimentary sequence underlying southwestern Ontario was to provide a basis for the assembly and integration of site-specific geoscientific data and to explain the influence of parameter and scenario uncertainty on predicted long-term geosphere barrier performance. The base-case analysis showed that solute transport in the Ordovician and lower Silurian is diffusion dominant. For the base-case parameters, the estimated mean life expectancy for the proposed DGR is more than 8 million years. The possible presence of a gas phase in the rock between the Cambrian and the Niagaran was not considered in the analyses of this paper. 9 refs., 2 tabs., 10 figs.

  17. The roles of the temperature on the structural and electronic properties of deep-level V{sub As}V{sub Ga} defects in gallium arsenide

    Ma, Deming, E-mail: xautmdm@163.com; Chen, Xi; Qiao, Hongbo; Shi, Wei; Li, Enling

    2015-07-15

    Highlights: • The energy gap of the Ga{sub As}As{sub Ga}V{sub As}V{sub Ga} is 0.82 eV. • Proves that the Ga{sub As}As{sub Ga}V{sub As}V{sub Ga} belongs to EL2 deep-level defect in GaAs. • Proves that EL2 and EL6 deep-level defects can transform into each other. • Temperature has an important effect on the microstructure of deep-level defects. - Abstract: The roles of temperature on the structural and electronic properties of V{sub As}V{sub Ga} defects in gallium arsenide have been studied by using ab-initio molecular dynamic (MD) simulation. Our calculated results show that the relatively stable quaternary complex defect of Ga{sub As}As{sub Ga}V{sub As}V{sub Ga} can be converted from the V{sub As}V{sub Ga} complex clusters defect between 300 K and 1173 K; however, from 1173 K to 1373 K, the decomposition of the complex defect Ga{sub As}As{sub Ga}V{sub As}V{sub Ga} occurs, turning into a deep-level V{sub As}V{sub Ga} cluster defect and an isolated As{sub Ga} antisite defect, and relevant defect of Ga{sub As} is recovered. The properties of Ga{sub As}As{sub Ga}V{sub As}V{sub Ga} defect has been studied by first-principles calculations based on hybrid density functional theory. Our calculated results show that the Ga{sub As}As{sub Ga}V{sub As}V{sub Ga} belongs to EL2 deep-level defect in GaAs. Thus, we reveal that the temperature has an important effect on the microstructure of deep-level defects and defect energy level in gallium arsenide that EL2 and EL6 deep-level defects have a certain correlation, which means they could transform into each other. Controlling temperature in the growth process of GaAs could change the microstructure of deep-level defects and defect energy levels in gallium arsenide materials, whereby affects the electron transport properties of materials.

  18. Capacitance probe for detection of anomalies in non-metallic plastic pipe

    Mathur, Mahendra P.; Spenik, James L.; Condon, Christopher M.; Anderson, Rodney; Driscoll, Daniel J.; Fincham, Jr., William L.; Monazam, Esmail R.

    2010-11-23

    The disclosure relates to analysis of materials using a capacitive sensor to detect anomalies through comparison of measured capacitances. The capacitive sensor is used in conjunction with a capacitance measurement device, a location device, and a processor in order to generate a capacitance versus location output which may be inspected for the detection and localization of anomalies within the material under test. The components may be carried as payload on an inspection vehicle which may traverse through a pipe interior, allowing evaluation of nonmetallic or plastic pipes when the piping exterior is not accessible. In an embodiment, supporting components are solid-state devices powered by a low voltage on-board power supply, providing for use in environments where voltage levels may be restricted.

  19. Thermal evolution and exhumation of deep-level batholithic exposures, southernmost Sierra Nevada, California

    Saleeby, J.; Farley, K.A.; Kistler, R.W.; Fleck, R.J.

    2007-01-01

    The Tehachapi complex lies at the southern end of the Sierra Nevada batholith adjacent to the Neogene-Quaternary Garlock fault. The complex is composed principally of high-pressure (8-10 kbar) Cretaceous batholithic rocks, and it represents the deepest exposed levels of a continuous oblique crustal section through the southern Sierra Nevada batholith. Over the southern ???100 km of this section, structural/petrologic continuity and geochronological data indicate that ???35 km of felsic to intermediate-composition crust was generated by copious arc magmatism primarily between 105 and 99 Ma. In the Tehachapi complex, these batholithic rocks intrude and are bounded to the west by similar-composition gneissic-textured high-pressure batholithic rocks emplaced at ca. 115-110 Ma. This lower crustal complex is bounded below by a regional thrust system, which in Late Cretaceous time tectonically eroded the underlying mantle lithosphere, and in series displaced and underplated the Rand Schist subduction assemblage by low-angle slip from the outboard Franciscan trench. Geophysical and mantle xenolith studies indicate that the remnants of this shallow subduction thrust descend northward through the crust and into the mantle, leaving the mantle lithosphere intact beneath the greater Sierra Nevada batholith. This north-dipping regional structure records an inflection in the Farallon plate, which was segmented into a shallow subduc-tion trajectory to the south and a normal steeper trajectory to the north. We combine new and published data from a broad spectrum of thermochronom-eters that together form a coherent data array constraining the thermal evolution of the complex. Integration of these data with published thermobarometric and petro-genetic data also constrains the tectonically driven decompression and exhumation history of the complex. The timing of arc magmatic construction of the complex, as denoted above, is resolved by a large body of U/Pb zircon ages. High

  20. Deep Uncertainties in Sea-Level Rise and Storm Surge Projections: Implications for Coastal Flood Risk Management.

    Oddo, Perry C; Lee, Ben S; Garner, Gregory G; Srikrishnan, Vivek; Reed, Patrick M; Forest, Chris E; Keller, Klaus

    2017-09-05

    Sea levels are rising in many areas around the world, posing risks to coastal communities and infrastructures. Strategies for managing these flood risks present decision challenges that require a combination of geophysical, economic, and infrastructure models. Previous studies have broken important new ground on the considerable tensions between the costs of upgrading infrastructure and the damages that could result from extreme flood events. However, many risk-based adaptation strategies remain silent on certain potentially important uncertainties, as well as the tradeoffs between competing objectives. Here, we implement and improve on a classic decision-analytical model (Van Dantzig 1956) to: (i) capture tradeoffs across conflicting stakeholder objectives, (ii) demonstrate the consequences of structural uncertainties in the sea-level rise and storm surge models, and (iii) identify the parametric uncertainties that most strongly influence each objective using global sensitivity analysis. We find that the flood adaptation model produces potentially myopic solutions when formulated using traditional mean-centric decision theory. Moving from a single-objective problem formulation to one with multiobjective tradeoffs dramatically expands the decision space, and highlights the need for compromise solutions to address stakeholder preferences. We find deep structural uncertainties that have large effects on the model outcome, with the storm surge parameters accounting for the greatest impacts. Global sensitivity analysis effectively identifies important parameter interactions that local methods overlook, and that could have critical implications for flood adaptation strategies. © 2017 Society for Risk Analysis.

  1. The split delivery capacitated team orienteering problem

    Archetti, C.; Bianchessi, N.; Speranza, M. G.; Hertz, A.

    2014-01-01

    In this article, we study the capacitated team orienteering problem where split deliveries are allowed. A set of potential customers is given, each associated with a demand and a profit. The set of customers to be served by a fleet of capacitated vehicles has to be identified in such a way that the

  2. Capacitance densitometer for flow regime identification

    Shipp, R.L. Jr.

    1978-01-01

    This invention relates to a capacitance densitometer for determining the flow regime of a two-phase flow system. A two-element capacitance densitometer is used in conjunction with a conventional single-beam gamma densitometer to unambiguously identify the prevailing flow regime and the average density of a flowing fluid

  3. Design of double capacitances infrasonic receiver

    Wang Changhai; Han Kuixia; Wang Fei

    2003-01-01

    The article introduces the theory of infrasonic generation and reception of nuclear explosion. An idea of the design of double capacitances infrasonic receiver using CPLD technology is given in it. Compare with the single capacitance infrasonic receiver, sensitivity of the improved receiver can be improved scores of times, dynamic range can be improved largely, and the whole performance gets improvement a lots

  4. Novel RF-MEMS capacitive switching structures

    Rottenberg, X.; Jansen, Henricus V.; Fiorini, P.; De Raedt, W.; Tilmans, H.A.C.

    2002-01-01

    This paper reports on novel RF-MEMS capacitive switching devices implementing an electrically floating metal layer covering the dielectric to ensure intimate contact with the bridge in the down state. This results in an optimal switch down capacitance and allows optimisation of the down/up

  5. The Pyramidal Capacitated Vehicle Routing Problem

    Lysgaard, Jens

    This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...

  6. The pyramidal capacitated vehicle routing problem

    Lysgaard, Jens

    2010-01-01

    This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...

  7. Scanning Capacitance Microscopy | Materials Science | NREL

    obtained using scanning capacitance microscopy. Top Right: Image of p-type and n-type material, obtained 'fingers' of light-colored n-type material on a yellow and blue background representing p-type material material, obtained using scanning capacitance microscopy, in a sample semiconductor device; the image shows

  8. RNA deep sequencing reveals novel candidate genes and polymorphisms in boar testis and liver tissues with divergent androstenone levels.

    Asep Gunawan

    Full Text Available Boar taint is an unpleasant smell and taste of pork meat derived from some entire male pigs. The main causes of boar taint are the two compounds androstenone (5α-androst-16-en-3-one and skatole (3-methylindole. It is crucial to understand the genetic mechanism of boar taint to select pigs for lower androstenone levels and thus reduce boar taint. The aim of the present study was to investigate transcriptome differences in boar testis and liver tissues with divergent androstenone levels using RNA deep sequencing (RNA-Seq. The total number of reads produced for each testis and liver sample ranged from 13,221,550 to 33,206,723 and 12,755,487 to 46,050,468, respectively. In testis samples 46 genes were differentially regulated whereas 25 genes showed differential expression in the liver. The fold change values ranged from -4.68 to 2.90 in testis samples and -2.86 to 3.89 in liver samples. Differentially regulated genes in high androstenone testis and liver samples were enriched in metabolic processes such as lipid metabolism, small molecule biochemistry and molecular transport. This study provides evidence for transcriptome profile and gene polymorphisms of boars with divergent androstenone level using RNA-Seq technology. Digital gene expression analysis identified candidate genes in flavin monooxygenease family, cytochrome P450 family and hydroxysteroid dehydrogenase family. Moreover, polymorphism and association analysis revealed mutation in IRG6, MX1, IFIT2, CYP7A1, FMO5 and KRT18 genes could be potential candidate markers for androstenone levels in boars. Further studies are required for proving the role of candidate genes to be used in genomic selection against boar taint in pig breeding programs.

  9. A review of the predictive modelling and data requirements for the long-term safety assessment of the deep disposal of low and intermediate level radioactive wastes

    Broyd, T.W.

    1988-06-01

    This report considers the Her Majesty's Inspectorate of Pollution research and modelling requirements for a robust post-closure radiological risk assessment methodology applicable to the deep disposal of Low-Level Wastes and Intermediate-Level Wastes. Two disposal concepts have been envisaged: horizontal tunnels or galleries in a low permeability stratum of a sedimentary sequence located inland; vertical boreholes or shafts up to 15m diameter lined with concrete and of the order 500m to 1000m deep sunk into the seabed within territorial coastal waters of the United Kingdom. (author)

  10. Persistent photocurrent and deep level traps in PLD-grown In-Ga-Zn-O thin films studied by thermally stimulated current spectroscopy

    Wang, Buguo; Anders, Jason; Leedy, Kevin; Schuette, Michael; Look, David

    2018-02-01

    InGaZnO (IGZO) is a promising semiconductor material for thin-film transistors (TFTs) used in DC and RF switching applications, especially since it can be grown at low temperatures on a wide variety of substrates. Enhancement-mode TFTs based on IGZO thin films grown by pulsed laser deposition (PLD) have been recently fabricated and these transistors show excellent performance; however, compositional variations and defects can adversely affect film quality, especially in regard to electrical properties. In this study, we use thermally stimulated current (TSC) spectroscopy to characterize the electrical properties and the deep traps in PLD-grown IGZO thin films. It was found that the as-grown sample has a DC activation energy of 0.62 eV, and two major traps with activation energies at 0.16-0.26 eV and at 0.90 eV. However, a strong persistent photocurrent (PPC) sometimes exists in the as-grown sample, so we carry out post-growth annealing in an attempt to mitigate the effect. It was found that annealing in argon increases the conduction, produces more PPC and also makes more traps observable. Annealing in air makes the film more resistive, and removes PPC and all traps but one. This work demonstrates that current-based trap emission, such as that associated with the TSC, can effectively reveal electronic defects in highlyresistive semiconductor materials, especially those are not amenable to capacitance-based techniques, such as deeplevel transient spectroscopy (DLTS).

  11. Capacitive Biosensors and Molecularly Imprinted Electrodes.

    Ertürk, Gizem; Mattiasson, Bo

    2017-02-17

    Capacitive biosensors belong to the group of affinity biosensors that operate by registering direct binding between the sensor surface and the target molecule. This type of biosensors measures the changes in dielectric properties and/or thickness of the dielectric layer at the electrolyte/electrode interface. Capacitive biosensors have so far been successfully used for detection of proteins, nucleotides, heavy metals, saccharides, small organic molecules and microbial cells. In recent years, the microcontact imprinting method has been used to create very sensitive and selective biorecognition cavities on surfaces of capacitive electrodes. This chapter summarizes the principle and different applications of capacitive biosensors with an emphasis on microcontact imprinting method with its recent capacitive biosensor applications.

  12. Dual-wavelength photo-Hall effect spectroscopy of deep levels in high resistive CdZnTe with negative differential photoconductivity

    Musiienko, A.; Grill, R.; Moravec, P.; Korcsmáros, G.; Rejhon, M.; Pekárek, J.; Elhadidy, H.; Šedivý, L.; Vasylchenko, I.

    2018-04-01

    Photo-Hall effect spectroscopy was used in the study of deep levels in high resistive CdZnTe. The monochromator excitation in the photon energy range 0.65-1.77 eV was complemented by a laser diode high-intensity excitation at selected photon energies. A single sample characterized by multiple unusual features like negative differential photoconductivity and anomalous depression of electron mobility was chosen for the detailed study involving measurements at both the steady and dynamic regimes. We revealed that the Hall mobility and photoconductivity can be both enhanced and suppressed by an additional illumination at certain photon energies. The anomalous mobility decrease was explained by an excitation of the inhomogeneously distributed deep level at the energy Ev + 1.0 eV, thus enhancing potential non-uniformities. The appearance of negative differential photoconductivity was interpreted by an intensified electron occupancy of that level by a direct valence band-to-level excitation. Modified Shockley-Read-Hall theory was used for fitting experimental results by a model comprising five deep levels. Properties of the deep levels and their impact on the device performance were deduced.

  13. A piezoelectric micro control valve with integrated capacitive sensing for ambulant blood pressure waveform monitoring

    Groen, Maarten S.; Wu, Kai; Brookhuis, Robert A.; van Houwelingen, Marc J.; Brouwer, Dannis M.; Lötters, Joost C.; Wiegerink, Remco J.

    2014-12-01

    We have designed and characterized a MEMS microvalve with built-in capacitive displacement sensing and fitted it with a miniature piezoelectric actuator to achieve active valve control. The integrated displacement sensor enables high bandwidth proportional control of the gas flow through the valve. This is an essential requirement for non-invasive blood pressure waveform monitoring based on following the arterial pressure with a counter pressure. Using the capacitive sensor, we demonstrate negligible hysteresis in the valve control characteristics. Fabrication of the valve requires only two mask steps for deep reactive ion etching (DRIE) and one release etch.

  14. A piezoelectric micro control valve with integrated capacitive sensing for ambulant blood pressure waveform monitoring

    Groen, Maarten S; Wu, Kai; Brookhuis, Robert A; Lötters, Joost C; Wiegerink, Remco J; Van Houwelingen, Marc J; Brouwer, Dannis M

    2014-01-01

    We have designed and characterized a MEMS microvalve with built-in capacitive displacement sensing and fitted it with a miniature piezoelectric actuator to achieve active valve control. The integrated displacement sensor enables high bandwidth proportional control of the gas flow through the valve. This is an essential requirement for non-invasive blood pressure waveform monitoring based on following the arterial pressure with a counter pressure. Using the capacitive sensor, we demonstrate negligible hysteresis in the valve control characteristics. Fabrication of the valve requires only two mask steps for deep reactive ion etching (DRIE) and one release etch. (paper)

  15. Siting, design and construction of a deep geological repository for the disposal of high level and alpha bearing wastes

    1990-06-01

    The main objective of this document is to summarize the basic principles and approaches to siting, design and construction of a deep geological repository for disposal of high level and alpha bearing radioactive wastes, as commonly agreed upon by Member States. This report is addressed to decision makers and technical managers as well as to specialists planning for siting, design and construction of geological repositories for disposal of high level and alpha bearing wastes. This document is intended to provide Member States of the IAEA with a summary outline for the responsible implementing organizations to use for siting, designing and constructing confinement systems for high level and alpha bearing radioactive waste in accordance with the protection objectives set by national regulating authorities or derived from safety fundamentals and standards of the IAEA. The protection objectives will be achieved by the isolation of the radionuclides from the environment by a repository system, which consists of a series of man made and natural safety barriers. Engineered barriers are used to enhance natural geological containment in a variety of ways. They must complement the natural barriers to provide adequate safety and necessary redundancy to the barrier system to ensure that safety standards are met. Because of the long timescales involved and the important role of the natural barrier formed by the host rock, the site selection process is a key activity in the repository design and development programme. The choice of the site, the investigation of its geological setting, the exploration of the regional hydrogeological setting and the primary underground excavations are all considered to be part of the siting process. 16 refs

  16. DeepPy: Pythonic deep learning

    Larsen, Anders Boesen Lindbo

    This technical report introduces DeepPy – a deep learning framework built on top of NumPy with GPU acceleration. DeepPy bridges the gap between highperformance neural networks and the ease of development from Python/NumPy. Users with a background in scientific computing in Python will quickly...... be able to understand and change the DeepPy codebase as it is mainly implemented using high-level NumPy primitives. Moreover, DeepPy supports complex network architectures by letting the user compose mathematical expressions as directed graphs. The latest version is available at http...

  17. The role of surface and deep-level defects on the emission of tin oxide quantum dots

    Kumar, Vinod; Kumar, Vijay; Som, S; Ntwaeaborwa, O M; Swart, H C; Neethling, J H; Lee, Mike

    2014-01-01

    This paper reports on the role of surface and deep-level defects on the blue emission of tin oxide quantum dots (SnO 2 QDs) synthesized by the solution-combustion method at different combustion temperatures. X-ray diffraction studies showed the formation of a single rutile SnO 2 phase with a tetragonal lattice structure. High resolution transmission electron microscopy studies revealed an increase in the average dot size from 2.2 to 3.6 nm with an increase of the combustion temperature from 350 to 550 °C. A decrease in the band gap value from 3.37 to 2.76 eV was observed with the increase in dot size due to the quantum confinement effect. The photoluminescence emission was measured for excitation at 325 nm and it showed a broad blue emission band for all the combustion temperatures studied. This was due to the creation of various oxygen and tin vacancies/defects as confirmed by x-ray photoelectron spectroscopy data. The origin of the blue emission in the SnO 2 QDs is discussed with the help of an energy band diagram. (paper)

  18. Correlation of proton irradiation induced threshold voltage shifts to deep level traps in AlGaN/GaN heterostructures

    Zhang, Z.; Cardwell, D.; Sasikumar, A.; Arehart, A. R.; Ringel, S. A., E-mail: ringel.5@osu.edu [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Kyle, E. C. H.; Speck, J. S. [Department of Materials, University of California, Santa Barbara, California 93106-5050 (United States); Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D. [Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235 (United States)

    2016-04-28

    The impact of proton irradiation on the threshold voltage (V{sub T}) of AlGaN/GaN heterostructures is systematically investigated to enhance the understanding of a primary component of the degradation of irradiated high electron mobility transistors. The value of V{sub T} was found to increase monotonically as a function of 1.8 MeV proton fluence in a sub-linear manner reaching 0.63 V at a fluence of 1 × 10{sup 14} cm{sup −2}. Silvaco Atlas simulations of V{sub T} shifts caused by GaN buffer traps using experimentally measured introduction rates, and energy levels closely match the experimental results. Different buffer designs lead to different V{sub T} dependences on proton irradiation, confirming that deep, acceptor-like defects in the GaN buffer are primarily responsible for the observed V{sub T} shifts. The proton irradiation induced V{sub T} shifts are found to depend on the barrier thickness in a linear fashion; thus, scaling the barrier thickness could be an effective way to reduce such degradation.

  19. Correlation of proton irradiation induced threshold voltage shifts to deep level traps in AlGaN/GaN heterostructures

    Zhang, Z.; Cardwell, D.; Sasikumar, A.; Kyle, E. C. H.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; Speck, J. S.; Arehart, A. R.; Ringel, S. A.

    2016-04-01

    The impact of proton irradiation on the threshold voltage (VT) of AlGaN/GaN heterostructures is systematically investigated to enhance the understanding of a primary component of the degradation of irradiated high electron mobility transistors. The value of VT was found to increase monotonically as a function of 1.8 MeV proton fluence in a sub-linear manner reaching 0.63 V at a fluence of 1 × 1014 cm-2. Silvaco Atlas simulations of VT shifts caused by GaN buffer traps using experimentally measured introduction rates, and energy levels closely match the experimental results. Different buffer designs lead to different VT dependences on proton irradiation, confirming that deep, acceptor-like defects in the GaN buffer are primarily responsible for the observed VT shifts. The proton irradiation induced VT shifts are found to depend on the barrier thickness in a linear fashion; thus, scaling the barrier thickness could be an effective way to reduce such degradation.

  20. Correlation of proton irradiation induced threshold voltage shifts to deep level traps in AlGaN/GaN heterostructures

    Zhang, Z.; Cardwell, D.; Sasikumar, A.; Arehart, A. R.; Ringel, S. A.; Kyle, E. C. H.; Speck, J. S.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.

    2016-01-01

    The impact of proton irradiation on the threshold voltage (V T ) of AlGaN/GaN heterostructures is systematically investigated to enhance the understanding of a primary component of the degradation of irradiated high electron mobility transistors. The value of V T was found to increase monotonically as a function of 1.8 MeV proton fluence in a sub-linear manner reaching 0.63 V at a fluence of 1 × 10 14  cm −2 . Silvaco Atlas simulations of V T shifts caused by GaN buffer traps using experimentally measured introduction rates, and energy levels closely match the experimental results. Different buffer designs lead to different V T dependences on proton irradiation, confirming that deep, acceptor-like defects in the GaN buffer are primarily responsible for the observed V T shifts. The proton irradiation induced V T shifts are found to depend on the barrier thickness in a linear fashion; thus, scaling the barrier thickness could be an effective way to reduce such degradation.

  1. The potential of natural analogues in assessing systems for deep disposal of high-level radioactive waste

    Chapman, N.A.; Smellie, J.A.T.

    1984-08-01

    Many of the processes which will lead to the breakdown of engineered barriers and the mobilisation of radionuclides in a deep waste repository have analogies in natural geological systems. These 'natural analogues' are seen as a particularly important means of validating predictive models, under the broad heading of radionuclide migration, which are used in long-term safety analyses. Their principal value is the opportunity they provide to examine processes occurring over geological timescales, hence allowing more confident extrapolation of short timescales experimental data. This report begins by reviewing the processes leading to breakdown of containment in a high-level radioactive waste repository in crystalline bedrock and the subsequent migration mechanisms for radionuclides back to the biosphere. Nine specific processes are identified as being of the most significance in migration models, based on available sensitivity analyses. Existing studies are assessed and possibilities considered for additional analogues. Conclusions are drawn for each process as to the extent to which analogues validate current predictions on scale and effect, longevity of function, etc. Where possible, quantitative evaluations are given, derived from analogue studies. A considerable amount of the information reviewed and presented could be used in the assessment of disposal of other waste types in other host rocks. (Auth.)

  2. OPG's deep geologic repository for low and intermediate level waste - public participation and aboriginal engagement

    Wilson, M.

    2011-01-01

    Ontario Power Generation (OPG)'s Public Participation and Aboriginal Engagement Program for the proposed Deep Geologic Repository (DGR) for low and intermediate level waste (L and ILW) began with the signing of a Memorandum of Understanding (MOU) in 2002 between OPG and the Municipality of Kincardine. The MOU set out the terms under which the two parties would jointly study the feasibility of different options for the long-term management of L and ILW at the Bruce nuclear site. A consultant, independent from both the Municipality of Kincardine and OPG, was retained to manage the assessment of options as well as a communication plan to ensure the public and Aboriginal peoples were kept apprised of all activities associated with the MOU. This early commitment to transparency and openness, with its ensuing opportunities for the public and Aboriginal peoples to become informed, ask questions, and engage in meaningful two-way dialogue about the early assessment of options, established the foundation and later became the hallmark of the DGR Project's Public Participation and Aboriginal Engagement program. This paper provides an overview of the development, nature and results of that program as it has evolved through the early investigative stages of options and through the environmental assessment and licencing process for the proposed DGR Project. (author)

  3. The OPG/Kincardine hosting agreement for a deep geologic repository for OPG's low- and intermediate-level waste

    Castellan, A.G.; Barker, D.E.

    2006-01-01

    A Hosting Agreement has been reached between Ontario Power Generation and the Municipality of Kincardine for the purpose of siting a long-term management facility for low- and intermediate-level radioactive waste at the Western Waste Management Facility. Following an independent review of the feasibility of three options for a long-term facility at the site, including a review of the safety, geotechnical feasibility, social and economic effects and potential environmental effects, Kincardine passed a resolution indicating their preference for a Deep Geologic Repository. A Host Community Agreement has been negotiated based on this preference, and on information that had been gathered from municipal authorities at other locations that have hosted similar facilities. The Hosting Agreement includes financial compensation, totalling $35.7 million (Canadian 2004) to the Municipality of Kincardine and to four surrounding municipalities. The financial aspects include lump sum payments based on achieving specific project milestones as well as annual payments to each of the municipalities. The payments are indexed to inflation, and are also contingent on the municipalities acting reasonably and in good faith during the licencing process of the proposed facility. In addition to the fees, the Agreement includes provision for a Property Value Protection Plan that would provide residents with compensation in the event that there is depreciation in property value shown to directly result from a release from the proposed facility. New permanent OPG jobs supporting the project would be located at the site. OPG and Kincardine will support a centre of nuclear excellence. (author)

  4. The hydrogeologic environment for a proposed deep geologic repository in Canada for low and intermediate level radioactive waste - 59285

    Sykes, Jonathan F.; Normani, Stefano D.; Yin, Yong; Jensen, Mark R.

    2012-01-01

    A Deep Geologic Repository (DGR) for low and intermediate level radioactive waste has been proposed by Ontario Power Generation for the Bruce nuclear site in Ontario, Canada. As proposed the DGR would be constructed at a depth of about 680 m below ground surface within the argillaceous Ordovician limestone of the Cobourg Formation. This paper describes the hydrogeology of the DGR site developed through both site characterization studies and regional-scale numerical modelling analysis. The analysis provides a framework for the assembly and integration of the site-specific geo-scientific data and examines the factors that influence the predicted long-term performance of the geosphere barrier. Flow system evolution was accomplished using both the density-dependent FRAC3DVS-OPG flow and transport model and the two-phase gas and water flow computational model TOUGH2-MP. In the geologic framework of the Province of Ontario, the DGR is located on the eastern flank of the Michigan Basin. Borehole logs covering Southern Ontario combined with site-specific data from 6 deep boreholes have been used to define the structural contours and hydrogeologic properties at the regional-scale of the modelled 31 sedimentary strata that may be partially present above the Precambrian crystalline basement rock. The regional-scale domain encompasses an approximately 18500 km 2 region extending from Lake Huron to Georgian Bay. The groundwater zone below the Devonian includes units containing stagnant water having high concentrations of total dissolved solids that can exceed 300 g/L. The Ordovician sediments are significantly under-pressured. The horizontal hydraulic conductivity for the Cobourg limestone is estimated to be 2x10 -14 m/s based on straddle-packer hydraulic tests. The low advective velocities in the Cobourg and other Ordovician units result in solute transport that is diffusion dominant with Peclet numbers less than 0:003 for a characteristic length of unity. Long

  5. Electronic structure of deep levels in silicon. A study of gold, magnesium, and iron centers in silicon

    Thilderkvist, A. L.

    1994-02-01

    The electronic structure of gold, magnesium and iron related deep centers in silicon is investigated. Their deep and shallow levels are studied by means of fourier transform spectroscopy, combined with uniaxial stress and Zeeman spectroscopy. The neutral substitutional gold center in silicon is investigated and the center is paramagnetic, S=1/2, with g||≅2.8 and g≅0, and has a static distortion. Reorientation between different equivalent distortions is observed even at 1.9 K. A gold pair center in silicon is studied and several line series, with a zero-phonon line followed by several phonon replicas, are observed. Uniaxial stress and Zeeman results reveal a trigonal symmetry of the center, which together with the high dissociation energy of 1.7 eV suggests that the center consists of two nearest-neighbor substitutional gold atoms. A divacancy model is employed to explain the electronic properties of the center. The interstitial magnesium double donor in silicon in its two charge states Mg o and Mg + is investigated. Deviations in the binding energies of the excited states from those calculated within the effective-mass theory (EMT) are found and explained by a perturbation in the central-cell region. The quadratic Zeeman effect of shallow donors in silicon is analyzed within the framework of the EMT using a numerical approach. The wave functions are calculated in a discrete radial mesh and the Zeeman Hamiltonian has be evaluated for the lowest excited states for fields up to 6 T. The neutral interstitial iron defect in silicon gives rise to two sets of line spectra. The first set arises when an electron is excited to a shallow donor like state where the electron is decoupled from the Fe + core which has a 4 T 1 ground state term. The second set arises when an excited electron of a 1 symmetry is coupled by exchange interaction to the core, yielding at 5 T 1 final state. Experiments determine the multiplet splitting of the 4 T 1 and 5 T 1 states due to spring

  6. Long-term degradation of organic polymers under conditions found in deep repositories for low and intermediate-level wastes

    Warthmann, R.; Mosberger, L.; Baier, U.

    2013-06-01

    On behalf of Nagra, the Environmental Biotechnology Section of the Zürich University of Applied Sciences in Wädenswil investigated the potential for microbiological degradation of organic polymers under the conditions found in a deep geological repository for low- and intermediate-level waste (L/ILW). The existing scientific literature on the topic was analysed, some thermodynamic calculations carried out and input was elicited from internationally recognised experts in the field. The study was restricted to a few substances which, in terms of mass, are most significant in the Swiss L/ILW inventory; these are polystyrene (PS), polyvinyl chloride (PVC), other plastics and bitumen. There were no clear indications in the literature that the polymer structure of synthetic polymers is biodegraded under anoxic conditions. However, functional groups of ion exchangers and plasticizers in plastics are considered to be readily available and biodegradable. The greatest obstacle to biological degradation of synthetic polymers is depolymerisation to produce labile monomers. As energy is generally required for such breakdown, the chances of this process taking place outside the cells are very low. In so far as they are present, monomers are, in principle, anaerobically biodegradable. Thermodynamic considerations indicate that degradation of synthetic polymers under repository conditions is theoretically possible. However, the degradation of polystyrene is very close to thermodynamic equilibrium and the usable energy for microorganisms would barely be sufficient. Under high H2 partial pressures, it is predicted that there will be a thermodynamic inhibition of anaerobic degradation, as certain interim steps in degradation are endergonic. The starting conditions for microbial growth in a deep repository are unfavourable in terms of availability of water and prevailing pH values. Practically no known microorganisms can tolerate the combination of these conditions; most known

  7. Reconciling the sea level record of the last deglaciation with the δ18O spectra from deep sea cores

    Bard, Edouard; Columbia Univ., Palisades, NY; Arnold, Maurice; Duplessy, J.-C.

    1991-01-01

    In this paper we use the oxygen isotope record as a transient tracer to study palaeoceanography during the last deglaciation. By using 14 C and 18 O data obtained on four deep sea sediment cores, we show the presence of a measurable lag between the deglacial δ 18 O signal observed in the deep Atlantic and the deep Indo-Pacific oceans. Our study confirms that the major meltwater discharge occurred via the North Atlantic and that the thermohaline circulation was operating during the deglacial transition. (Author)

  8. MECHANISMS OF MANTLE‐CRUST INTERACTION AT DEEP LEVELS OF COLLISION OROGENS (CASE OF THE OLKHON REGION, WEST PRIBAIKALIE

    A. G. Vladimirov

    2017-01-01

    zones, which is fol‐ lowed by metamorphic magma mingling under viscous deformation conditions. The mafic magmas intruding to the level of the granulite facies facilitated the deep anatexis and formation of synmetamorphic hypersthene plagiogranites (U‐Pb isotope dating: 500–490 Ma and high‐K stress granites. In the Chernorud granulite zone, intense ductile‐plastic and brittle‐plastic deformations accompanied the processes of metamorphism, intrusion and formation of gabbro‐ pyroxenites and the anatexis of the crustal substance. As a result, the intrusive bodies were fragmented, and specific tectonic structures termed ‘metamorphic magma‐mingling’ were formed. All the tectonic and magmatic structures were subsequently ‘sealed up’ by K‐Na synkinematic granites at the regressive stage under conditions of the amphibo‐ lite‐facies metamorphism (U‐Pb and Ar‐Ar isotope dating: 470–460 Ma.

  9. Maximum flood hazard assessment for OPG's deep geologic repository for low and intermediate level waste

    Nimmrichter, P.; McClintock, J.; Peng, J.; Leung, H.

    2011-01-01

    Ontario Power Generation (OPG) has entered a process to seek Environmental Assessment and licensing approvals to construct a Deep Geologic Repository (DGR) for Low and Intermediate Level Radioactive Waste (L&ILW) near the existing Western Waste Management Facility (WWMF) at the Bruce nuclear site in the Municipality of Kincardine, Ontario. In support of the design of the proposed DGR project, maximum flood stages were estimated for potential flood hazard risks associated with coastal, riverine and direct precipitation flooding. The estimation of lake/coastal flooding for the Bruce nuclear site considered potential extreme water levels in Lake Huron, storm surge and seiche, wind waves, and tsunamis. The riverine flood hazard assessment considered the Probable Maximum Flood (PMF) within the local watersheds, and within local drainage areas that will be directly impacted by the site development. A series of hydraulic models were developed, based on DGR project site grading and ditching, to assess the impact of a Probable Maximum Precipitation (PMP) occurring directly at the DGR site. Overall, this flood assessment concluded there is no potential for lake or riverine based flooding and the DGR area is not affected by tsunamis. However, it was also concluded from the results of this analysis that the PMF in proximity to the critical DGR operational areas and infrastructure would be higher than the proposed elevation of the entrance to the underground works. This paper provides an overview of the assessment of potential flood hazard risks associated with coastal, riverine and direct precipitation flooding that was completed for the DGR development. (author)

  10. Structural, electronic properties, and quantum capacitance of B, N and P-doped armchair carbon nanotubes

    Mousavi-Khoshdel, S. Morteza, E-mail: mmousavi@iust.ac.ir [Department of Chemistry, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Jahanbakhsh-bonab, Parisa [Department of Chemistry, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Targholi, Ehsan [Young Researchers and Elite Club, Abhar Branch, Islamic Azad University, Abhar (Iran, Islamic Republic of)

    2016-10-07

    Using DFT calculations, we study the structural parameters, electronic properties and quantum capacitance of N, B, and P-doped armchair carbon nanotubes (CNTs). Fermi level shifts towards conduction band and valence band in N- and B-doped CNTs, respectively. While in the case of P atom, despite having an extra valence electron than carbon, there is no shift in Fermi level. The results revealed from a symmetric capacitance enhancement in P-doped CNT and an asymmetric capacitance enhancement in B and N-doped CNTs. The greatest amount of quantum capacitance of N-doped (6, 6) CNT could be achieved at the concentration range of 0.1–0.15. - Highlights: • Exploration of variation in quantum capacitance of CNTs through doping N, B and P atoms. • Quantum capacitance of CNTs is sensitive to impurities entered in carbon nanotubes. • Maximum quantum capacitance of N-doped CNTs is achieved at the concentration range of 0.1–0.15.

  11. Decontamination by replacing soil and soil cover with deep-level soil in flower beds and vacant places in Northern Fukushima Prefecture

    Sugiura, Hiroyuki; Kawano, Keisuke; Kayama, Yukihiko; Koube, Nobuyuki

    2012-01-01

    Radioactivity decontamination by replacing soil and soil cover with deep-level soil and soil cover in flower beds and a vacant place in Northern Fukushima Prefecture were studied, which experienced radioactive contamination due to the accident at the TEPCO's Fukushima Daiichi Nuclear Power Plant. Radioactivity counting rate 1 cm above the soil surface after replacing surface soil with uncontaminated deep-level soil decreased to 13.7% of the control in gardens. The concentration of radioactive cesium in the cover soil increased after 132 days; however, it decreased in the old surface soil under the cover soil in flower beds. A 10 cm deep-level soil cover placed by heavy machinery decreased the radiation dose rate to 70.8% of the control and radioactivity counting rate to 24.6% in the vacant place. Replacing the radioactively contaminated surface soil and soil cover with a deep-level soil was a reasonable decontamination method for the garden and vacant place because it is quick, cost effective and labour efficient. (author)

  12. First generation of deep n-well CMOS MAPS with in-pixel sparsification for the ILC vertex detector

    Traversi, Gianluca; Bulgheroni, Antonio; Caccia, Massimo; Jastrzab, Marcin; Manghisoni, Massimo; Pozzati, Enrico; Ratti, Lodovico; Re, Valerio

    2009-01-01

    In this paper we present the characterization results relevant to a deep n-well (DNW) CMOS active pixel sensor chip designed for vertexing applications at the International Linear Collider. In this chip, named sparsified digital readout (SDR0), for the first time we implemented a sparsification logic at the pixel level. The DNW available in deep submicron CMOS processes is used to collect the charge released in the substrate, and signal processing is performed by a classical optimum amplifying stage for capacitive detectors. In this work, the experimental characterization of the SDR0 chip, including data from radioactive source ( 55 Fe) tests, will be presented.

  13. Negative quantum capacitance induced by midgap states in single-layer graphene.

    Wang, Lin; Wang, Yang; Chen, Xiaolong; Zhu, Wei; Zhu, Chao; Wu, Zefei; Han, Yu; Zhang, Mingwei; Li, Wei; He, Yuheng; Xiong, Wei; Law, Kam Tuen; Su, Dangsheng; Wang, Ning

    2013-01-01

    We demonstrate that single-layer graphene (SLG) decorated with a high density of Ag adatoms displays the unconventional phenomenon of negative quantum capacitance. The Ag adatoms act as resonant impurities and form nearly dispersionless resonant impurity bands near the charge neutrality point (CNP). Resonant impurities quench the kinetic energy and drive the electrons to the Coulomb energy dominated regime with negative compressibility. In the absence of a magnetic field, negative quantum capacitance is observed near the CNP. In the quantum Hall regime, negative quantum capacitance behavior at several Landau level positions is displayed, which is associated with the quenching of kinetic energy by the formation of Landau levels. The negative quantum capacitance effect near the CNP is further enhanced in the presence of Landau levels due to the magnetic-field-enhanced Coulomb interactions.

  14. Reducing the capacitance of piezoelectric film sensors

    González, Martín G., E-mail: mggonza@fi.uba.ar [Grupo de Láser, Óptica de Materiales y Aplicaciones Electromagnéticas (GLOMAE), Departamento de Física, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, C1063ACV Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1425FQB Buenos Aires (Argentina); Sorichetti, Patricio A.; Santiago, Guillermo D. [Grupo de Láser, Óptica de Materiales y Aplicaciones Electromagnéticas (GLOMAE), Departamento de Física, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, C1063ACV Buenos Aires (Argentina)

    2016-04-15

    We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N{sup 2}, whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

  15. Reducing the capacitance of piezoelectric film sensors

    González, Martín G.; Sorichetti, Patricio A.; Santiago, Guillermo D.

    2016-01-01

    We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N"2, whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

  16. A miniature electrical capacitance tomograph

    York, T. A.; Phua, T. N.; Reichelt, L.; Pawlowski, A.; Kneer, R.

    2006-08-01

    The paper describes a miniature electrical capacitance tomography system. This is based on a custom CMOS silicon integrated circuit comprising eight channels of signal conditioning electronics to source drive signals and measure voltages. Electrodes are deposited around a hole that is fabricated, using ultrasonic drilling, through a ceramic substrate and has an average diameter of 0.75 mm. The custom chip is interfaced to a host computer via a bespoke data acquisition system based on a microcontroller, field programmable logic device and wide shift register. This provides fast capture of up to 750 frames of data prior to uploading to the host computer. Data capture rates of about 6000 frames per second have been achieved for the eight-electrode sensor. This rate could be increased but at the expense of signal to noise. Captured data are uploaded to a PC, via a RS232 interface, for off-line imaging. Initial tests are reported for the static case involving 200 µm diameter rods that are placed in the sensor and for the dynamic case using the dose from an inhaler.

  17. Beating of magnetic oscillations in a graphene device probed by quantum capacitance

    Tahir, M.; Schwingenschlö gl, Udo

    2012-01-01

    We report the quantum capacitance of a monolayergraphene device in an external perpendicular magnetic field including the effects of Rashba spin-orbit interaction(SOI). The SOI mixes the spin up and spin down states of neighbouring Landau levels into two (unequally spaced) energy branches. In order to investigate the role of the SOI for the electronic transport, we study the density of states to probe the quantum capacitance of monolayergraphene.SOIeffects on the quantum magnetic oscillations (Shubnikov de Haas and de Hass-van Alphen) are deduced from the quantum capacitance.

  18. Beating of magnetic oscillations in a graphene device probed by quantum capacitance

    Tahir, M.

    2012-07-05

    We report the quantum capacitance of a monolayergraphene device in an external perpendicular magnetic field including the effects of Rashba spin-orbit interaction(SOI). The SOI mixes the spin up and spin down states of neighbouring Landau levels into two (unequally spaced) energy branches. In order to investigate the role of the SOI for the electronic transport, we study the density of states to probe the quantum capacitance of monolayergraphene.SOIeffects on the quantum magnetic oscillations (Shubnikov de Haas and de Hass-van Alphen) are deduced from the quantum capacitance.

  19. Final disposal of high-level radioactive waste in deep boreholes. An evaluation based on recent research on the bedrock at great depths

    Aahaell, Karl-Inge

    2006-05-01

    New knowledge in hydrogeology and boring technology have opened the possibility to use deep boreholes as a repository for the Swedish high-level radioactive wastes. The determining property is that the repository can be housed in the stable bedrock at levels where the ground water has no contact with the biosphere and disposal and sealing can take place without disturbing the ground water stratification outside the disposal area. An advantage compared to a shallow repository of KBS-3 type, that is now being planned in Sweden, is that a borehole repository is likely to be technologically more robust, since the concept 'deep boreholes' seems to admit such a deep disposal that the entire disposal area would be surrounded by stable density-layered ground water, while a KBS-3 repository would be surrounded by moving ground water in contact with level close to the surface. This hydrological difference is of great importance for the safety in scenarios with leaching of radioactive substances. A deep repository is also less vulnerable for effects from natural events such as glaciation and earthquakes as well as from technological mishaps and terrorist actions. A crucial factor is, however, that the radioactive waste can be disposed of, in a secure way, at the intended depth, which will require new research and technology development

  20. Deep levels in a-plane, high Mg-content MgxZn1−xO epitaxial layers grown by molecular beam epitaxy

    Gür, Emre; Tabares, G.; Hierro, A.; Arehart, A.; Ringel, S. A.; Chauveau, J. M.

    2012-01-01

    Deep level defects in n-type unintentionally doped a-plane Mg x Zn 1−x O, grown by molecular beam epitaxy on r-plane sapphire were fully characterized using deep level optical spectroscopy (DLOS) and related methods. Four compositions of Mg x Zn 1−x O were examined with x = 0.31, 0.44, 0.52, and 0.56 together with a control ZnO sample. DLOS measurements revealed the presence of five deep levels in each Mg-containing sample, having energy levels of E c − 1.4 eV, 2.1 eV, 2.6 V, and E v + 0.3 eV and 0.6 eV. For all Mg compositions, the activation energies of the first three states were constant with respect to the conduction band edge, whereas the latter two revealed constant activation energies with respect to the valence band edge. In contrast to the ternary materials, only three levels, at E c − 2.1 eV, E v + 0.3 eV, and 0.6 eV, were observed for the ZnO control sample in this systematically grown series of samples. Substantially higher concentrations of the deep levels at E v + 0.3 eV and E c − 2.1 eV were observed in ZnO compared to the Mg alloyed samples. Moreover, there is a general invariance of trap concentration of the E v + 0.3 eV and 0.6 eV levels on Mg content, while at least and order of magnitude dependency of the E c − 1.4 eV and E c − 2.6 eV levels in Mg alloyed samples.

  1. Tuning of deep level emission in highly oriented electrodeposited ZnO nanorods by post growth annealing treatments

    Simimol, A.; Manikandanath, N. T.; Chowdhury, Prasanta; Barshilia, Harish C.; Anappara, Aji A.

    2014-01-01

    Highly dense and c-axis oriented zinc oxide (ZnO) nanorods with hexagonal wurtzite facets were deposited on fluorine doped tin oxide coated glass substrates by a simple and cost-effective electrodeposition method at low bath temperature (80 °C). The as-grown samples were then annealed at various temperatures (T A  = 100–500 °C) in different environments (e.g., zinc, oxygen, air, and vacuum) to understand their photoluminescence (PL) behavior in the ultra-violet (UV) and the visible regions. The PL results revealed that the as-deposited ZnO nanorods consisted of oxygen vacancy (V O ), zinc interstitial (Zn i ), and oxygen interstitial (O i ) defects and these can be reduced significantly by annealing in different environments at optimal annealing temperatures. However, the intensity of deep level emission increased for T A greater than the optimized values for the respective environments due to the introduction of various defect centers. For example, for T A  ≥ 450 °C in the oxygen and air environments, the density of O i defects increased, whereas, the green emission associated with V O is dominant in the vacuum annealed (T A  = 500 °C) ZnO nanorods. The UV peak red shifted after the post-growth annealing treatments in all the environments and the vacuum annealed sample exhibited highest UV peak intensity. The observations from the PL data are supported by the micro-Raman spectroscopy. The present study gives new insight into the origin of different defects that exist in the electrodeposited ZnO nanorods and how these defects can be precisely controlled in order to get the desired emissions for the opto-electronic applications

  2. The potential of natural analogues in assessing systems for deep disposal of high-level radioactive waste

    Chapman, N.A.; McKinley, I.G.; Smellie, J.A.T.

    1984-08-01

    Many of the processes which will lead to the breakdown of engineered barriers and the mobilization of radionuclides in a deep waste repository have analogies in natural geological systems. These 'natural analogues' are seen as a particularly important means of validating predictive models, under the broad heading of radionuclide migration, which are used in long-term safety analyses. Their principal value is the opportunity they provide to examine processes occurring over geological timescales, hence allowing more confident extrapolation of short timescales experimental data. This report begins by reviewing the processes leading to breakdown of containment in a high-level radioactive waste repository in crystalline bedrock and the subsequent migration mechanisms for radionuclides back to the biosphere. Nine specific processes are identified as being of the most significance in migration models, based on available sensitivity analyses. These processes are considered separately in detail, reviewing first the mechanisms involved and the most important unknown then the types of natural analogue which could most usefully provide supporting evidence for the effects of the process. Conclusions are drawn, for each process as to the extent to which analogues validate current predictions on scale and effect, longevity of function, etc. Where possible, quantitative evaluations are given, derived from analogue studies. A summary is provided of the conclusions for each process, and the most important topics for further studies are listed. Specific examples of these requisite analogues are given. The report emphasises throughout the importance of linking analogues to well defined processes, concluding that analogues of complete disposal systems do not exist. The results are seen to be widely applicable. A considerable amount of the information reviewed and presented could be used in the assessment of disposal of other waste types in other host rocks. (Author)

  3. Deep level transient spectroscopy studies of charge traps introduced into silicon by channeling ion implantation of phosphorus

    McCallum, J.C.; Lay, M.; Deenapanray, P.N.K.; Jagadish, C.

    2002-01-01

    Full text: The operating conditions of a silicon-based quantum computer are expected to place stringent requirements on the quality of the material and the processes used to make it. In the Special Research Centre for Quantum Computer Technology, ion implantation is one of the principle processing techniques under investigation for forming an ordered array of phosphorus atoms. This technique introduces defect centres in silicon which act as charge traps. Charge traps are expected to be detrimental to operation of the device. These defect centres, their dependence on ion implantation and thermal annealing conditions are being quantified using Deep Level Transient Spectroscopy (DLTS). Since the aspect ratio of the masks required for the top-down fabrication process restrict the incident ions to a range of angles in which they may undergo channeling implantation in the silicon substrate, we have examined the effect of channeling implantation on the nature and quantity of the charge traps produced. This is the first time that DLTS studies have been performed for channeling implantation of a dopant species in silicon. DLTS is well-suited to the dose regime of ∼10 11 P/cm 3 required for the quantum computer, however, a standard DLTS measurement is unable to probe the shallow depth range of ∼ 20 nm required for the P atoms (∼ 10-15 keV implantation energy). Our aim has therefore been to perform P implants in the appropriate dose regime but using higher implantation energies, ∼ 75-450 keV, where DLTS can directly identify and profile the charge traps induced by the implantation step and monitor their annealing characteristics during subsequent processing. To map the behaviour observed in this energy regime onto the low energy range required for the quantum computer we are comparing the DLTS results to damage profiles predicted by the Monte Carlo code Crystal Trim which is used in the semiconductor industry to simulate ion implantation processes in crystalline

  4. Automatic abdominal multi-organ segmentation using deep convolutional neural network and time-implicit level sets.

    Hu, Peijun; Wu, Fa; Peng, Jialin; Bao, Yuanyuan; Chen, Feng; Kong, Dexing

    2017-03-01

    Multi-organ segmentation from CT images is an essential step for computer-aided diagnosis and surgery planning. However, manual delineation of the organs by radiologists is tedious, time-consuming and poorly reproducible. Therefore, we propose a fully automatic method for the segmentation of multiple organs from three-dimensional abdominal CT images. The proposed method employs deep fully convolutional neural networks (CNNs) for organ detection and segmentation, which is further refined by a time-implicit multi-phase evolution method. Firstly, a 3D CNN is trained to automatically localize and delineate the organs of interest with a probability prediction map. The learned probability map provides both subject-specific spatial priors and initialization for subsequent fine segmentation. Then, for the refinement of the multi-organ segmentation, image intensity models, probability priors as well as a disjoint region constraint are incorporated into an unified energy functional. Finally, a novel time-implicit multi-phase level-set algorithm is utilized to efficiently optimize the proposed energy functional model. Our method has been evaluated on 140 abdominal CT scans for the segmentation of four organs (liver, spleen and both kidneys). With respect to the ground truth, average Dice overlap ratios for the liver, spleen and both kidneys are 96.0, 94.2 and 95.4%, respectively, and average symmetric surface distance is less than 1.3 mm for all the segmented organs. The computation time for a CT volume is 125 s in average. The achieved accuracy compares well to state-of-the-art methods with much higher efficiency. A fully automatic method for multi-organ segmentation from abdominal CT images was developed and evaluated. The results demonstrated its potential in clinical usage with high effectiveness, robustness and efficiency.

  5. Capacitive density measurement for supercritical hydrogen

    Funke, Th; Haberstroh, Ch; Szoucsek, K.; Schott, S.; Kunze, K.

    2017-12-01

    A new approach for automotive hydrogen storage systems is the so-called cryo-compressed hydrogen storage (CcH2). It has a potential for increased energy densities and thus bigger hydrogen amounts onboard, which is the main attractiveness for car manufacturers such as BMW. This system has further advantages in terms of safety, refueling and cooling potential. The current filling level measurement by means of pressure and temperature measurement and subsequent density calculation faces challenges especially in terms of precision. A promising alternative is the capacitive gauge. This measuring principle can determine the filling level of the CcH2 tank with significantly smaller tolerances. The measuring principle is based on different dielectric constants of gaseous and liquid hydrogen. These differences are successfully leveraged in liquid hydrogen storage systems (LH2). The present theoretical analysis shows that the dielectric values of CcH2 in the relevant operating range are comparable to LH2, thus achieving similarly good accuracy. The present work discusses embodiments and implementations for such a sensor in the CcH2 tank.

  6. Resistive and Capacitive Based Sensing Technologies

    Winncy Y. Du

    2008-04-01

    Full Text Available Resistive and capacitive (RC sensors are the most commonly used sensors. Their applications span homeland security, industry, environment, space, traffic control, home automation, aviation, and medicine. More than 30% of modern sensors are direct or indirect applications of the RC sensing principles. This paper reviews resistive and capacitive sensing technologies. The physical principles of resistive sensors are governed by several important laws and phenomena such as Ohm’s Law, Wiedemann-Franz Law; Photoconductive-, Piezoresistive-, and Thermoresistive Effects. The applications of these principles are presented through a variety of examples including accelerometers, flame detectors, pressure/flow rate sensors, RTDs, hygristors, chemiresistors, and bio-impedance sensors. The capacitive sensors are described through their three configurations: parallel (flat, cylindrical (coaxial, and spherical (concentric. Each configuration is discussed with respect to its geometric structure, function, and application in various sensor designs. Capacitance sensor arrays are also presented in the paper.

  7. Capacitive Cells for Dielectric Constant Measurement

    Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco

    2015-01-01

    A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.

  8. Complementary surface charge for enhanced capacitive deionization

    Gao, X.; Porada, S.; Omosebi, A.; Liu, K.L.; Biesheuvel, P.M.; Landon, J.

    2016-01-01

    Commercially available activated carbon cloth electrodes are treated using nitric acid and ethylenediamine solutions, resulting in chemical surface charge enhanced carbon electrodes for capacitive deionization (CDI) applications. Surface charge enhanced electrodes are then configured in a CDI

  9. Capacitance and surface of carbons in supercapacitors

    Lobato Ortega, Belén; Suárez Fernández, Loreto; Guardia, Laura; Álvarez Centeno, Teresa

    2017-01-01

    This research is focused in the missing link between the specific surface area of carbons surface and their electrochemical capacitance. Current protocols used for the characterization of carbons applied in supercapacitors electrodes induce inconsistencies in the values of the interfacial capacitance (in F m−2), which is hindering the optimization of supercapacitors. The constraints of both the physisorption of N2 at 77 K and the standard methods used for the isotherm analysis frequently lead...

  10. Development of electrical capacitance sensor for tomography

    Rasif Mohd Zain; Jaafar Abdullah; Ismail Mustapha; Sazrol Azizee Ariff; Susan Maria Sipaun; Lojius Lombigit

    2004-01-01

    Electrical capacitance tomography (ECT) is one of the successful methods for imaging 2-phase liquid/gas mixture in oil pipelines and solids/gas mixture in fluidized bed and pneumatic conveying system for improvement of process plants. This paper presents the design development of an electrical capacitance sensor for use with an ECT system. This project is aimed at developing a demonstration ECT unit to be used in the oil pipe line. (Author)

  11. Automatic Power Factor Correction Using Capacitive Bank

    Mr.Anant Kumar Tiwari,; Mrs. Durga Sharma

    2014-01-01

    The power factor correction of electrical loads is a problem common to all industrial companies. Earlier the power factor correction was done by adjusting the capacitive bank manually [1]. The automated power factor corrector (APFC) using capacitive load bank is helpful in providing the power factor correction. Proposed automated project involves measuring the power factor value from the load using microcontroller. The design of this auto-adjustable power factor correction is ...

  12. Narrow gap electronegative capacitive discharges

    Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

    2013-10-15

    Narrow gap electronegative (EN) capacitive discharges are widely used in industry and have unique features not found in conventional discharges. In this paper, plasma parameters are determined over a range of decreasing gap length L from values for which an electropositive (EP) edge exists (2-region case) to smaller L-values for which the EN region connects directly to the sheath (1-region case). Parametric studies are performed at applied voltage V{sub rf}=500 V for pressures of 10, 25, 50, and 100 mTorr, and additionally at 50 mTorr for 1000 and 2000 V. Numerical results are given for a parallel plate oxygen discharge using a planar 1D3v (1 spatial dimension, 3 velocity components) particle-in-cell (PIC) code. New interesting phenomena are found for the case in which an EP edge does not exist. This 1-region case has not previously been investigated in detail, either numerically or analytically. In particular, attachment in the sheaths is important, and the central electron density n{sub e0} is depressed below the density n{sub esh} at the sheath edge. The sheath oscillations also extend into the EN core, creating an edge region lying within the sheath and not characterized by the standard diffusion in an EN plasma. An analytical model is developed using minimal inputs from the PIC results, and compared to the PIC results for a base case at V{sub rf}=500 V and 50 mTorr, showing good agreement. Selected comparisons are made at the other voltages and pressures. A self-consistent model is also developed and compared to the PIC results, giving reasonable agreement.

  13. E-beam irradiation effect on CdSe/ZnSe QD formation by MBE: deep level transient spectroscopy and cathodoluminescence studies

    Kozlovsky, V I; Litvinov, V G; Sadofyev, Yu G

    2004-01-01

    CdSe/ZnSe structures containing 1 or 15 thin (3-5 monolayers) CdSe layers were studied by cathodoluminescence (CL) and deep level transient spectroscopy (DLTS). The DLTS spectra consisted of peaks from deep levels (DLs) and an additional intense peak due to electron emission from the ground quantized level in the CdSe layers. Activation energy of this additional peak correlated with an energy of the CdSe-layer emission line in the CL spectra. Electron-beam irradiation of the structure during the growth process was found to influence the DLTS and CL spectra of the CdSe layers, shifting the CdSe-layer emission line to the long-wave side. The obtained results are explained using the assumption that e-beam irradiation stimulates the formation of quantum dots of various sizes in the CdSe layers

  14. Deep bore well water level fluctuations in the Koyna region, India: the presence of a low order dynamical system in a seismically active environment

    D. V. Ramana

    2009-05-01

    Full Text Available Water level fluctuations in deep bore wells in the vicinity of seismically active Koyna region in western India provides an opportunity to understand the causative mechanism underlying reservoir-triggered earthquakes. As the crustal porous rocks behave nonlinearly, their characteristics can be obtained by analysing water level fluctuations, which reflect an integrated response of the medium. A Fractal dimension is one such measure of nonlinear characteristics of porous rock as observed in water level data from the Koyna region. It is inferred in our study that a low nonlinear dynamical system with three variables can predict the water level fluctuations in bore wells.

  15. Hydrogeologic modelling in support of a proposed deep geologic repository in Canada for low and intermediate level radioactive waste - 16264

    Sykes, Jonathan F.; Normani, Stefano D.; Yin, Yong; Sykes, Eric A.; Jensen, Mark R.

    2009-01-01

    A Deep Geologic Repository (DGR) for Low and Intermediate Level radioactive waste has been proposed by Ontario Power Generation for the Bruce Nuclear Power Development site in Ontario, Canada. The DGR is to be constructed at a depth of about 680 m below ground surface within the argillaceous Ordovician limestone of the Cobourg Formation. This paper describes a regional-scale geologic conceptual model for the DGR site and analyzes flow system evolution using the FRAC3DVSOPG flow and transport model. This provides a framework for the assembly and integration of site-specific geo-scientific data that explains and illustrates the factors that influence the predicted long-term performance of the geosphere barrier. In the geologic framework of the Province of Ontario, the Bruce DGR is located at the eastern edge of the Michigan Basin. Borehole logs covering Southern Ontario combined with site specific data have been used to define the structural contours at the regional and site scale of the 31 sedimentary strata that may be present above the Precambrian crystalline basement rock. The regional-scale domain encompasses an 18.500 km 2 region extending from Lake Huron to Georgian Bay. The groundwater zone below the Devonian is characterized by units containing stagnant water having high concentrations of total dissolved solids that can exceed 300 g/l. The computational sequence involves the calculation of steady-state density independent flow that is used as the initial condition for the determination of pseudo-equilibrium for a density dependent flow system that has an initial TDS distribution developed from observed data. Long-term simulations that consider future glaciation scenarios include the impact of ice thickness and permafrost. The selection of the performance measure used to evaluate a groundwater system is important. The traditional metric of average water particle travel time is inappropriate for geologic units such as the Ordovician where solute transport is

  16. Final deposition of high-level nuclear waste in very deep boreholes. An evaluation based on recent research of bedrock conditions at great depths

    Aahaell, Karl-Inge

    2007-01-01

    This report evaluates the feasibility of very deep borehole disposal of high-level nuclear waste, e.g., spent nuclear fuel, in the light of recent technological developments and research on the characteristics of bedrock at extreme depths. The evaluation finds that new knowledge in the field of hydrogeology and technical advances in drilling technology have advanced the possibility of using very deep boreholes (3-5 km) for disposal of the Swedish nuclear waste. Decisive factors are (1) that the repository can be located in stable bedrock at a level where the groundwater is isolated from the biosphere, and (2) that the waste can be deposited and the boreholes permanently sealed without causing long-term disturbances in the density-stratification of the groundwater that surrounds the repository. Very deep borehole disposal might offer important advantage compared to the relatively more shallow KBS approach that is presently planned to be used by the Swedish nuclear industry in Sweden, in that it has the potential of being more robust. The reason for this is that very deep borehole disposal appears to permit emplacement of the waste at depths where the entire repository zone would be surrounded by stable, density-stratified groundwater having no contact with the surface, whereas a KBS-3 repository would be surrounded by upwardly mobile groundwater. This hydro-geological difference is a major safety factor, which is particularly apparent in all scenarios that envisage leakage of radioactive substances. Another advantage of a repository at a depth of 3 to 5 km is that it is less vulnerable to impacts from expected events (e.g., changes in groundwater conditions during future ice ages) as well as undesired events (e.g. such as terrorist actions, technical malfunction and major local earthquakes). Decisive for the feasibility of a repository based on the very deep borehole concept is, however, the ability to emplace the waste without failures. In order to achieve this

  17. Evidence for two distinct defects contributing to the H4 deep-level transient spectroscopy peak in electron-irradiated InP

    Darwich, R.; Massarani, B.; Kaaka, M.; Awad, F.

    2000-01-01

    Deep-level transient spectroscopy (DLTS) has been used to study the dominant deep-level H4 produced in InP by electron irradiation. The characteristics of the H4 peak in Zn-doped Inp has been studied as a function of pulse duration (t p ) before and after annealing. The results show that at least two traps contribute to the H4 peak: one is a fast trap (labeled H4 f ) and the other is a show trap (labeled H4 s ). This is show through several results concerning the activation energy, the capture cross section, the full width at half-maximum, and the peak temperature shift. It is shown that both traps are irradiation defects created in P sublattice. (authors)

  18. Carbon flow electrodes for continuous operation of capacitive deionization and capacitive mixing energy generation

    Porada, S.; Hamelers, H.V.M.; Bryjak, M.; Presser, V.; Biesheuvel, P.M.; Weingarth, D.

    2014-01-01

    Capacitive technologies, such as capacitive deionization and energy harvesting based on mixing energy (“capmix” and “CO2 energy”), are characterized by intermittent operation: phases of ion electrosorption from the water are followed by system regeneration. From a system application point of view,

  19. Electric double-layer capacitance between an ionic liquid and few-layer graphene.

    Uesugi, Eri; Goto, Hidenori; Eguchi, Ritsuko; Fujiwara, Akihiko; Kubozono, Yoshihiro

    2013-01-01

    Ionic-liquid gates have a high carrier density due to their atomically thin electric double layer (EDL) and extremely large geometrical capacitance Cg. However, a high carrier density in graphene has not been achieved even with ionic-liquid gates because the EDL capacitance CEDL between the ionic liquid and graphene involves the series connection of Cg and the quantum capacitance Cq, which is proportional to the density of states. We investigated the variables that determine CEDL at the molecular level by varying the number of graphene layers n and thereby optimising Cq. The CEDL value is governed by Cq at n 4. This transition with n indicates a composite nature for CEDL. Our finding clarifies a universal principle that determines capacitance on a microscopic scale, and provides nanotechnological perspectives on charge accumulation and energy storage using an ultimately thin capacitor.

  20. Direct observation and measurements of neutron induced deep levels responsible for N{sub eff} changes in high resistivity silicon detectors using TCT

    Li, Z.; Li, C.J. [Brookhaven National Lab., Upton, NY (United States); Eremin, V.; Verbitskaya, E. [AN SSSR, Leningrad (Russian Federation). Fiziko-Tekhnicheskij Inst.

    1996-03-01

    Neutron induced deep levels responsible for changes of space charge concentration {ital N{sub eff}} in high resistivity silicon detectors have been observed directly using the transient current technique (TCT). It has been observed by TCT that the absolute value and sign of {ital N{sub eff}} experience changes due to the trapping of non- equilibrium free carriers generated near the surface (about 5 micrometers depth into the silicon) by short wavelength laser pulses in fully depleted detectors. Electron trapping causes {ital N{sub eff}} to change toward negative direction (or more acceptor-like space charges) and hole trapping causes {ital N{sub eff}} to change toward positive direction (or more donor-like space charges). The specific temperature associated with these {ital N{sub eff}} changes are those of the frozen-up temperatures for carrier emission of the corresponding deep levels. The carrier capture cross sections of various deep levels have been measured directly using different free carrier injection schemes. 10 refs., 12 figs., 3 tabs.

  1. Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods

    Alnoor, Hatim, E-mail: hatim.alnoor@liu.se; Chey, Chan Oeurn; Pozina, Galia; Willander, Magnus; Nur, Omer [Department of Science and Technology (ITN), Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden); Liu, Xianjie; Khranovskyy, Volodymyr [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-583 81 Linköping (Sweden)

    2015-08-15

    Hexagonal c-axis oriented zinc oxide (ZnO) nanorods (NRs) with 120-300 nm diameters are synthesized via the low temperature aqueous chemical route at 80 °C on silver-coated glass substrates. The influence of varying the precursor solutions stirring durations on the concentration and spatial distributions of deep level defects in ZnO NRs is investigated. Room temperature micro-photoluminesnce (μ-PL) spectra were collected for all samples. Cathodoluminescence (CL) spectra of the as-synthesized NRs reveal a significant change in the intensity ratio of the near band edge emission (NBE) to the deep-level emission (DLE) peaks with increasing stirring durations. This is attributed to the variation in the concentration of the oxygen-deficiency with increasing stirring durations as suggested from the X-ray photoelectron spectroscopy analysis. Spatially resolved CL spectra taken along individual NRs revealed that stirring the precursor solutions for relatively short duration (1-3 h), which likely induced high super saturation under thermodynamic equilibrium during the synthesis process, is observed to favor the formation of point defects moving towards the tip of the NRs. In contrary, stirring for longer duration (5-15 h) will induce low super saturation favoring the formation of point defects located at the bottom of the NRs. These findings demonstrate that it is possible to control the concentration and spatial distribution of deep level defects in ZnO NRs by varying the stirring durations of the precursor solutions.

  2. Diode characteristics and residual deep-level defects of p+n abrupt junctions fabricated by rapid thermal annealing of boron implanted silicon

    Usami, A.; Katayama, M.; Wada, T.; Tokuda, Y.

    1987-01-01

    p + n diodes were fabricated by rapid thermal annealing (RTA) of boron implanted silicon in the annealing temperature range 700-1100 0 C for around 7 s, and the RTA temperature dependence of electrical characteristics of these diodes was studied. Deep-level transient spectroscopy (DLTS) measurements were made to evaluate residual deep-level defects in the n-type bulk. Three electron traps were observed in p + n diodes fabricated by RTA at 700 0 C. It was considered that these three traps were residual point defects near the tail of the implantation damage after RTA. Residual defect concentrations increased in the range 700-900 0 C and decreased in the range 1000-1100 0 C. The growth of defects in the bulk was ascribed to the diffusion of defects from the implanted layer during RTA. Concentrations of electron traps observed in p + n diodes fabricated by RTA at 1100 0 C were approx. 10 12 cm -3 . It was found that these residual deep-level defects observed by DLTS were inefficient generation-recombination centres since the reverse current was independent of the RTA temperatures. (author)

  3. Deep circulation in the Indian and Pacific Oceans and its implication for the dumping of low-level radioactive waste

    Harries, J.R.

    1980-06-01

    The complexity of ocean transport processes has meant that the limits for the dumping of low-activity radioactive wastes have had to be based on very simplified models of the oceans. This report discusses the models used to determine dumping limits and contrasts them with the known ocean circulation patterns. The deep circulations of the Indian and Pacific Oceans are reviewed to provide a basis for estimating the possible destinations and likely transit times for dissolved material released at the ocean floor

  4. Capacitive behavior of highly-oxidized graphite

    Ciszewski, Mateusz; Mianowski, Andrzej

    2014-09-01

    Capacitive behavior of a highly-oxidized graphite is presented in this paper. The graphite oxide was synthesized using an oxidizing mixture of potassium chlorate and concentrated fuming nitric acid. As-oxidized graphite was quantitatively and qualitatively analyzed with respect to the oxygen content and the species of oxygen-containing groups. Electrochemical measurements were performed in a two-electrode symmetric cell using KOH electrolyte. It was shown that prolonged oxidation causes an increase in the oxygen content while the interlayer distance remains constant. Specific capacitance increased with oxygen content in the electrode as a result of pseudo-capacitive effects, from 0.47 to 0.54 F/g for a scan rate of 20 mV/s and 0.67 to 1.15 F/g for a scan rate of 5 mV/s. Better cyclability was observed for the electrode with a higher oxygen amount.

  5. Negative capacitance in a ferroelectric capacitor.

    Khan, Asif Islam; Chatterjee, Korok; Wang, Brian; Drapcho, Steven; You, Long; Serrao, Claudy; Bakaul, Saidur Rahman; Ramesh, Ramamoorthy; Salahuddin, Sayeef

    2015-02-01

    The Boltzmann distribution of electrons poses a fundamental barrier to lowering energy dissipation in conventional electronics, often termed as Boltzmann Tyranny. Negative capacitance in ferroelectric materials, which stems from the stored energy of a phase transition, could provide a solution, but a direct measurement of negative capacitance has so far been elusive. Here, we report the observation of negative capacitance in a thin, epitaxial ferroelectric film. When a voltage pulse is applied, the voltage across the ferroelectric capacitor is found to be decreasing with time--in exactly the opposite direction to which voltage for a regular capacitor should change. Analysis of this 'inductance'-like behaviour from a capacitor presents an unprecedented insight into the intrinsic energy profile of the ferroelectric material and could pave the way for completely new applications.

  6. Carbon nanofiber supercapacitors with large areal capacitances

    McDonough, James R.

    2009-01-01

    We develop supercapacitor (SC) devices with large per-area capacitances by utilizing three-dimensional (3D) porous substrates. Carbon nanofibers (CNFs) functioning as active SC electrodes are grown on 3D nickel foam. The 3D porous substrates facilitate a mass loading of active electrodes and per-area capacitance as large as 60 mg/ cm2 and 1.2 F/ cm2, respectively. We optimize SC performance by developing an annealing-free CNF growth process that minimizes undesirable nickel carbide formation. Superior per-area capacitances described here suggest that 3D porous substrates are useful in various energy storage devices in which per-area performance is critical. © 2009 American Institute of Physics.

  7. Proton irradiation effects on deep level states in Mg-doped p-type GaN grown by ammonia-based molecular beam epitaxy

    Zhang, Z.; Arehart, A. R.; Kyle, E. C. H.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; Speck, J. S.; Ringel, S. A.

    2015-01-01

    The impact of proton irradiation on the deep level states throughout the Mg-doped p-type GaN bandgap is investigated using deep level transient and optical spectroscopies. Exposure to 1.8 MeV protons of 1 × 1013 cm-2 and 3 × 1013 cm-2 fluences not only introduces a trap with an EV + 1.02 eV activation energy but also brings monotonic increases in concentration for as-grown deep states at EV + 0.48 eV, EV + 2.42 eV, EV + 3.00 eV, and EV + 3.28 eV. The non-uniform sensitivities for individual states suggest different physical sources and/or defect generation mechanisms. Comparing with prior theoretical calculations reveals that several traps are consistent with associations to nitrogen vacancy, nitrogen interstitial, and gallium vacancy origins, and thus are likely generated through displacing nitrogen and gallium atoms from the crystal lattice in proton irradiation environment.

  8. Detecting size and shape of bodies capacitatively

    Walton, H.

    1980-01-01

    The size and shape of a body is determined by rolling it between the plates of capacitors and measuring the capacitance changes. A capacitor comprising two parallel, spaced wires inclined to the rolling direction and above and below the rolling body scans sections of the body along its longitudinal axis, another determines the body's lengths and a third comprising two non-parallel wires determines the position of the body. The capacitance changes are compared with those produced by a body of known size and shape so that the size and shape of the body can be determined. (author)

  9. Feasibility of disposal of high-level radioactive waste into the seabed. volume 7: Review of laboratory investigations of radionuclide migration through deep-sea sediments

    Brush, L.H.

    1988-01-01

    One of the options suggested for disposal of high-level radioactive waste resulting from the generation of nuclear power is burial beneath the deep ocean floor in geologically stable sediment formations which have no economic value. The 8-volume series provides an assessment of the technical feasibility and radiological safety of this disposal concept based on the results obtained by ten years of co-operation and information exchange among the Member countries participating in the NEA Seabed Working Group. This volume contains a review of the laboratory investigations of radionuclide migration through deep-sea sediments. In addition, it discusses the data selected for the radiological assessment, on the basis of both field and laboratory studies

  10. Feasibility of disposal of high-level radioactive waste into the seabed. Volume 6: Deep-sea biology, biological processes and radiobiology

    Pentreath, R.J.; Hargrave, B.T.; Roe, H.S.J.; Sibuet, M.

    1988-01-01

    One of the options suggested for disposal of high-level radioactive waste resulting from the generation of nuclear power is burial beneath the deep ocean floor in geologically stable sediment formations which have no economic value. The 8-volume series provides an assessment of the technical feasibility and radiological safety of this disposal concept based on the results obtained by ten years of co-operation and information exchange among the Member countries participating in the NEA Seabed Working Group. This report summarizes the biological description of selected sites, the means by which radionuclides could result in human exposure via seafood pathways, and the doses likely to be received by, and effects on, the deep-sea fauna

  11. The Design of Phase-Locked-Loop Circuit for Precision Capacitance Micrometer

    Li Shujie

    2016-01-01

    Full Text Available High precision non-contact micrometer is normally divided into three categories: inductance micrometer, capacitance micrometer and optical interferometer micrometer. The capacitance micrometer is widely used because it has high performance to price ratio. With the improvement of automation level, precision of capacitance micrometer is required higher and higher. Generally, capacitance micrometer consists of the capacitance sensor, capacitance/voltage conversion circuit, and modulation and demodulation circuits. However, due to the existing of resistors, capacitors and other components in the circuit, the phase shift of the carrier signal and the modulated signal might occur. In this case, the specific value of phase shift cannot be determined. Therefore, error caused by the phase shift cannot be eliminated. This will reduce the accuracy of micrometer. In this design, in order to eliminate the impact of the phase shift, the phase-locked-loop (PLL circuit is employed. Through the experiment, the function of tracking the input signal phase and frequency is achieved by the phase-locked-loop circuit. This signal processing method can also be applied to tuber electrical resistance tomography system and other precision measurement circuit.

  12. Characterization of deep level defects and thermally stimulated depolarization phenomena in La-doped TlInS{sub 2} layered semiconductor

    Seyidov, MirHasan Yu., E-mail: smirhasan@gyte.edu.tr; Suleymanov, Rauf A.; Mikailzade, Faik A. [Department of Physics, Gebze Technical University, Gebze, Kocaeli 41400 (Turkey); Institute of Physics of NAS of Azerbaijan, H. Javid ave. 33, Baku AZ-1143 (Azerbaijan); Kargın, Elif Orhan [Department of Physics, Gebze Technical University, Gebze, Kocaeli 41400 (Turkey); Odrinsky, Andrei P. [Institute of Technical Acoustics, National Academy of Sciences of Belarus, Lyudnikov ave. 13, Vitebsk 210717 (Belarus)

    2015-06-14

    Lanthanum-doped high quality TlInS{sub 2} (TlInS{sub 2}:La) ferroelectric-semiconductor was characterized by photo-induced current transient spectroscopy (PICTS). Different impurity centers are resolved and identified. Analyses of the experimental data were performed in order to determine the characteristic parameters of the extrinsic and intrinsic defects. The energies and capturing cross section of deep traps were obtained by using the heating rate method. The observed changes in the Thermally Stimulated Depolarization Currents (TSDC) near the phase transition points in TlInS{sub 2}:La ferroelectric-semiconductor are interpreted as a result of self-polarization of the crystal due to the internal electric field caused by charged defects. The TSDC spectra show the depolarization peaks, which are attributed to defects of dipolar origin. These peaks provide important information on the defect structure and localized energy states in TlInS{sub 2}:La. Thermal treatments of TlInS{sub 2}:La under an external electric field, which was applied at different temperatures, allowed us to identify a peak in TSDC which was originated from La-dopant. It was established that deep energy level trap BTE43, which are active at low temperature (T ≤ 156 K) and have activation energy 0.29 eV and the capture cross section 2.2 × 10{sup −14} cm{sup 2}, corresponds to the La dopant. According to the PICTS results, the deep level trap center B5 is activated in the temperature region of incommensurate (IC) phases of TlInS{sub 2}:La, having the giant static dielectric constant due to the structural disorders. From the PICTS simulation results for B5, native deep level trap having an activation energy of 0.3 eV and the capture cross section of 1.8 × 10{sup −16} cm{sup 2} were established. A substantial amount of residual space charges is trapped by the deep level localized energy states of B5 in IC-phase. While the external electric field is applied, permanent dipoles

  13. Characterization of deep level defects and thermally stimulated depolarization phenomena in La-doped TlInS2 layered semiconductor

    Seyidov, MirHasan Yu.; Suleymanov, Rauf A.; Mikailzade, Faik A.; Kargın, Elif Orhan; Odrinsky, Andrei P.

    2015-01-01

    Lanthanum-doped high quality TlInS 2 (TlInS 2 :La) ferroelectric-semiconductor was characterized by photo-induced current transient spectroscopy (PICTS). Different impurity centers are resolved and identified. Analyses of the experimental data were performed in order to determine the characteristic parameters of the extrinsic and intrinsic defects. The energies and capturing cross section of deep traps were obtained by using the heating rate method. The observed changes in the Thermally Stimulated Depolarization Currents (TSDC) near the phase transition points in TlInS 2 :La ferroelectric-semiconductor are interpreted as a result of self-polarization of the crystal due to the internal electric field caused by charged defects. The TSDC spectra show the depolarization peaks, which are attributed to defects of dipolar origin. These peaks provide important information on the defect structure and localized energy states in TlInS 2 :La. Thermal treatments of TlInS 2 :La under an external electric field, which was applied at different temperatures, allowed us to identify a peak in TSDC which was originated from La-dopant. It was established that deep energy level trap BTE43, which are active at low temperature (T ≤ 156 K) and have activation energy 0.29 eV and the capture cross section 2.2 × 10 −14 cm 2 , corresponds to the La dopant. According to the PICTS results, the deep level trap center B5 is activated in the temperature region of incommensurate (IC) phases of TlInS 2 :La, having the giant static dielectric constant due to the structural disorders. From the PICTS simulation results for B5, native deep level trap having an activation energy of 0.3 eV and the capture cross section of 1.8 × 10 −16 cm 2 were established. A substantial amount of residual space charges is trapped by the deep level localized energy states of B5 in IC-phase. While the external electric field is applied, permanent dipoles, which are originated from the charged B5

  14. Control of environmental impact of low-level aqueous fuel reprocessing wastes by deep-well disposal

    Trevorrow, L.E.; Steindler, M.J.

    1978-01-01

    The following conclusions are made: (1) the technology and much experience for this disposal method are available; (2) large areas of the U.S. offer geological formations suitable for deep well disposal, but substantial effort may be required in the choice of a specific site; (3) although costs are substantial, they are small compared to associated environmental and energy benefits; (4) impacts on water consumers would be minimized through regulatory checks of siting, construction, and monitoring, and also through natural dilution and radioactive decay; (5) disposal wells must satisfy regulations, of recently-increased stringency, on siting, design, construction, operation, monitoring, and decommissioning

  15. Development of an assessment methodology for the disposal of high-level radioactive waste into deep ocean sediments

    Murray, C.N.; Stanners, D.A.

    1982-01-01

    This paper presents the results of a theoretical study concerning the option of disposal of vitrified high activity waste (HAW) into deep ocean sediments. The development of a preliminary methodology is presented which concerns the assessment of the possible effects of a release of radioactivity on the ecosystem and eventually on man. As the long-term hazard is considered basically to be due to transuranic elements (and daughter products) the period studied for the assessment is from 10 3 to 10 6 years. A simple ecosystem model is developed so that the transfer of activity between different compartments of the systems, e.g. the sediment column, sediment-water interface, deep sea water column, can be estimated. A critical pathway analysis is made for an imaginary critical group in order to complete the assessment. A sensitivity analysis is undertaken using the computed minimum-maximum credible values for the different parameters used in the calculations in order to obtain a minimum-maximum dose range for a critical group. (Auth.)

  16. Deep level defects in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy

    Farzana, Esmat; Ahmadi, Elaheh; Speck, James S.; Arehart, Aaron R.; Ringel, Steven A.

    2018-04-01

    Deep level defects were characterized in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy (PAMBE) using deep level optical spectroscopy (DLOS) and deep level transient (thermal) spectroscopy (DLTS) applied to Ni/β-Ga2O3:Ge (010) Schottky diodes that displayed Schottky barrier heights of 1.50 eV. DLOS revealed states at EC - 2.00 eV, EC - 3.25 eV, and EC - 4.37 eV with concentrations on the order of 1016 cm-3, and a lower concentration level at EC - 1.27 eV. In contrast to these states within the middle and lower parts of the bandgap probed by DLOS, DLTS measurements revealed much lower concentrations of states within the upper bandgap region at EC - 0.1 - 0.2 eV and EC - 0.98 eV. There was no evidence of the commonly observed trap state at ˜EC - 0.82 eV that has been reported to dominate the DLTS spectrum in substrate materials synthesized by melt-based growth methods such as edge defined film fed growth (EFG) and Czochralski methods [Zhang et al., Appl. Phys. Lett. 108, 052105 (2016) and Irmscher et al., J. Appl. Phys. 110, 063720 (2011)]. This strong sensitivity of defect incorporation on crystal growth method and conditions is unsurprising, which for PAMBE-grown β-Ga2O3:Ge manifests as a relatively "clean" upper part of the bandgap. However, the states at ˜EC - 0.98 eV, EC - 2.00 eV, and EC - 4.37 eV are reminiscent of similar findings from these earlier results on EFG-grown materials, suggesting that possible common sources might also be present irrespective of growth method.

  17. Capacitors and Resistance-Capacitance Networks.

    Balabanian, Norman; Root, Augustin A.

    This programed textbook was developed under a contract with the United States Office of Education as Number 5 in a series of materials for use in an electrical engineering sequence. It is divided into three parts--(1) capacitors, (2) voltage-current relationships, and (3) simple resistance-capacitance networks. (DH)

  18. Thermodynamic cycle analysis for capacitive deionization

    Biesheuvel, P.M.

    2009-01-01

    Capacitive deionization (CDI) is an ion removal technology based on temporarily storing ions in the polarization layers of two oppositely positioned electrodes. Here we present a thermodynamic model for the minimum work required for ion separation in the fully reversible case by describing the ionic

  19. Performance relations in Capacitive Deionization systems

    Limpt, van B.

    2010-01-01

    Capacitive Deionization (CDI) is a relatively new deionization technology based on the temporary storage of ions on an electrically charged surface. By directing a flow between two oppositely charged surfaces, negatively charged ions will adsorb onto the positively charged surface, and positively

  20. Flexible PVDF ferroelectric capacitive temperature sensor

    Khan, Naveed; Omran, Hesham; Yao, Yingbang; Salama, Khaled N.

    2015-01-01

    sensitivity of 16pF/°C. The linearity measurement of the capacitance-temperature relation shows less than 0.7°C error from a best fit straight line. An LC oscillator based temperature sensor is demonstrated based on this capacitor.

  1. Comparison of gate capacitance extraction methodologies

    Kazmi, S.N.R.; Schmitz, Jurriaan

    2008-01-01

    In recent years, many new capacitance-voltage measurement approaches have been presented in literature. New approaches became necessary with the rapidly increasing gate current density in newer CMOS generations. Here we present a simulation platform using Silvaco software, to describe the full chain

  2. Inside-out electrical capacitance tomography

    Kjærsgaard-Rasmussen, Jimmy; Meyer, Knud Erik

    2011-01-01

    In this work we demonstrate the construction of an ‘inside-out’ sensor geometry for electrical capacitance tomography (ECT). The inside-out geometry has the electrodes placed around a tube, as usual, but measuring ‘outwards’. The flow between the electrodes and an outer tube is reconstructed...

  3. Overview of capacitive couplings in windings

    Djukic, N.; Encica, L.; Paulides, J.J.H.

    2015-01-01

    The use of electrical machines (EMs) with variable-frequency drives (VFDs) results in electromagnetic interference (EMI). At high frequencies (HFs) of conducted EMI, the impedance of an EM insulation system fed from a VFD is small due to the parasitic capacitive couplings. Thus, the conducted EMI

  4. Capacitive system detects and locates fluid leaks

    1966-01-01

    Electronic monitoring system automatically detects and locates minute leaks in seams of large fluid storage tanks and pipelines covered with thermal insulation. The system uses a capacitive tape-sensing element that is adhesively bonded over seams where fluid leaks are likely to occur.

  5. A reconsideration on deep sea bed disposal of high level radiological wastes. A post-Fukushima reflection on sustainable nuclear energy in Japan

    Yoshikawa, Hidekazu

    2013-01-01

    The ultimate disposal of high-level radioactive waste (HLW) is a common issue among all nuclear developing countries. However, this becomes especially a hard issue for sustainable nuclear energy in Japan after Fukushima Daiichi accident. In this paper, the difficulty of realizing underground HLW disposal in Japanese islands is first discussed from socio-political aspects. Then, revival of old idea of deep seabed disposal of HLW in Pacific Ocean is proposed as an alternative way of HLW disposal. Although this old idea had been abandoned in the past for the reason that it would violate London Convention which prohibits dumping radioactive wastes in public sea, the author will stress the merit of seabed disposal of HLW deep in Pacific Ocean not only from the view point of more safe and ultimate way of disposing HLWs (both vitrified and spent fuel) than by underground disposal, but also the emergence of new marine project by synergetic collaboration of rare-earth resource exploration from the deep sea floor in Pacific Ocean. (author)

  6. Highly sensitive micromachined capacitive pressure sensor with reduced hysteresis and low parasitic capacitance

    Pedersen, Thomas; Fragiacomo, Giulio; Hansen, Ole

    2009-01-01

    This paper describes the design and fabrication of a capacitive pressure sensor that has a large capacitance signal and a high sensitivity of 76 pF/bar in touch mode operation. Due to the large signal, problems with parasitic capacitances are avoided and hence it is possible to integrate the sensor...... bonding to create vacuum cavities. The exposed part of the sensor is perfectly flat such that it can be coated with corrosion resistant thin films. Hysteresis is an inherent problem in touch mode capacitive pressure sensors and a technique to significantly reduce it is presented....... with a discrete components electronics circuit for signal conditioning. Using an AC bridge electronics circuit a resolution of 8 mV/mbar is achieved. The large signal is obtained due to a novel membrane structure utilizing closely packed hexagonal elements. The sensor is fabricated in a process based on fusion...

  7. Nonlinear dynamics of capacitive charging and desalination by porous electrodes

    Biesheuvel, P.M.; Bazant, M.Z.

    2010-01-01

    The rapid and efficient exchange of ions between porous electrodes and aqueous solutions is important in many applications, such as electrical energy storage by supercapacitors, water desalination and purification by capacitive deionization, and capacitive extraction of renewable energy from a

  8. Decrease in the cytosolic NADP+-dependent isocitrate dehydrogenase activity through porcine sperm capacitation.

    Katoh, Yuki; Tamba, Michiko; Matsuda, Manabu; Kikuchi, Kazuhiro; Okamura, Naomichi

    2018-02-26

    In order to understand the molecular mechanisms involved in the sperm capacitation, we have identified the proteins tyrosine-phosphorylated during the capacitation especially in conjunction with the regulation of the levels of reactive oxygen species (ROS) in sperm. In the present study, the effects of the tyrosine phosphorylation of cytosolic NADP + -dependent isocitrate dehydrogenase (IDPc) on its catalytic activity and on the levels of ROS in sperm have been studied. The tyrosine phosphorylated IDPc showed a significantly lowered enzymatic activity. The immunocytochemical analyses using the highly specific antisera against IDPc revealed that IDPc was mainly localized to the principal piece of the porcine sperm flagellum. As IDPc is one of the major NADPH regenerating enzymes in porcine sperm, it is strongly suggested that the decrease in IDPc activity is involved in the increased levels of ROS, which results in the induction of hyperactivated flagellar movement and capacitation. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods

    Hatim Alnoor

    2015-08-01

    Full Text Available Hexagonal c-axis oriented zinc oxide (ZnO nanorods (NRs with 120-300 nm diameters are synthesized via the low temperature aqueous chemical route at 80 °C on silver-coated glass substrates. The influence of varying the precursor solutions stirring durations on the concentration and spatial distributions of deep level defects in ZnO NRs is investigated. Room temperature micro-photoluminesnce (μ-PL spectra were collected for all samples. Cathodoluminescence (CL spectra of the as-synthesized NRs reveal a significant change in the intensity ratio of the near band edge emission (NBE to the deep-level emission (DLE peaks with increasing stirring durations. This is attributed to the variation in the concentration of the oxygen-deficiency with increasing stirring durations as suggested from the X-ray photoelectron spectroscopy analysis. Spatially resolved CL spectra taken along individual NRs revealed that stirring the precursor solutions for relatively short duration (1-3 h, which likely induced high super saturation under thermodynamic equilibrium during the synthesis process, is observed to favor the formation of point defects moving towards the tip of the NRs. In contrary, stirring for longer duration (5-15 h will induce low super saturation favoring the formation of point defects located at the bottom of the NRs. These findings demonstrate that it is possible to control the concentration and spatial distribution of deep level defects in ZnO NRs by varying the stirring durations of the precursor solutions.

  10. Deep-level defects introduced by 1 MeV electron radiation in AlInGaP for multijunction space solar cells

    Lee, H.S.; Yamaguchi, M.; Ekins-Daukes, N. J.; Khan, A.; Takamoto, T.; Agui, T.; Kamimura, K.; Kaneiwa, M.; Imaizumi, M.; Ohshima, T.; Itoh, H.

    2005-01-01

    Presented in this paper are 1 MeV electron irradiation effects on wide-band-gap (1.97 eV) (Al 0.08 Ga 0.92 ) 0.52 In 0.48 P diodes and solar cells. The carrier removal rate estimated in p-AlInGaP with electron fluence is about 1 cm -1 , which is lower than that in InP and GaAs. From high-temperature deep-level transient spectroscopy measurements, a deep-level defect center such as majority-carrier (hole) trap H2 (E ν +0.90±0.05 eV) was observed. The changes in carrier concentrations (Δp) and trap densities as a function of electron fluence were compared, and as a result the total introduction rate, 0.39 cm -1 , of majority-carrier trap centers (H1 and H2) is different from the carrier removal rate, 1 cm -1 , in p-AlInGaP. From the minority-carrier injection annealing (100 mA/cm 2 ), the annealing activation energy of H2 defect is ΔE=0.60 eV, which is likely to be associated with a vacancy-phosphorus Frenkel pair (V p -P i ). The recovery of defect concentration and carrier concentration in the irradiated p-AlInGaP by injection relates that a deep-level defect H2 acts as a recombination center as well as compensator center

  11. A Methodology to analyze the biosphere in the assessment of deep geological repositories for high level radioactive waste

    Pinedo, P.; Smith, G.

    1996-11-01

    This report summarizes the work done and the achievements reached within the R and D Project that IMA/CIEMAT has had with ENRESA during 1993-1995. The overall R and D Project has a wide radiological protection context, but the work reported here relates only to the development of a Methodology for considering the Biosphere sub-system in the assessments of deep geological repositories for high radioactive wastes (HLW). The main areas concerned within the Methodology have to do with the Biosphere structure and morphology in the long-term relevant to deep disposal of HLW: in the contexts of the assessment of these systems, and appropriate modelling of the behaviour of radionuclides released to the biosphere system and with the associated human exposure. This document first provides a review of the past and present international and national concerns about the biosphere modelling and its importance in relation to the definition of safety criteria. A joint ENRESA/ANDRA/IPSN/CIEMAT study about the definition and practical descriptions of the biosphere systems under different climatic states is then summarized. The Methodology developed by IMA/CIEMAT is outlined with an illustration of the way it works. Different steps and procedures are included for a better practical understanding of the software tools developed within the project to support the application of the Methodology. This methodology is widely based on an international working group on ''Reference Biospheres'', part of the BIOMOVS II Project. Specific software developments have been carried out in collaboration with Qunti Sci Itd and with the Polytechnical University of Madrid. (Author)

  12. Intermittent-contact scanning capacitance microscopy imaging and modeling for overlay metrology

    Mayo, S.; Kopanski, J. J.; Guthrie, W. F.

    1998-01-01

    Overlay measurements of the relative alignment between sequential layers are one of the most critical issues for integrated circuit (IC) lithography. We have implemented on an AFM platform a new intermittent-contact scanning capacitance microscopy (IC-SCM) mode that is sensitive to the tip proximity to an IC interconnect, thus making it possible to image conductive structures buried under planarized dielectric layers. Such measurements can be used to measure IC metal-to-resist lithography overlay. The AFM conductive cantilever probe oscillating in a vertical plane was driven at frequency ω, below resonance. By measuring the tip-to-sample capacitance, the SCM signal is obtained as the difference in capacitance, ΔC(ω), at the amplitude extremes. Imaging of metallization structures was obtained with a bars-in-bars aluminum structure embedded in a planarized dielectric layer 1 μm thick. We have also modeled, with a two-dimensional (2D) electrostatic field simulator, IC-SCM overlay data of a metallization structure buried under a planarized dielectric having a patterned photoresist layer deposited on it. This structure, which simulates the metal-to-resist overlay between sequential IC levels, allows characterization of the technique sensitivity. The capacitance profile across identical size electrically isolated or grounded metal lines embedded in a dielectric was shown to be different. The floating line shows capacitance enhancement at the line edges, with a minimum at the line center. The grounded line shows a single capacitance maximum located at the line center, with no edge enhancement. For identical line dimensions, the capacitance is significantly larger for grounded lines making them easier to image. A nonlinear regression algorithm was developed to extract line center and overlay parameters with approximately 3 nm resolution at the 95% confidence level, showing the potential of this technique for sub-micrometer critical dimension metrology. Symmetric test

  13. Investigation of electrically active defects in InGaAs quantum wire intermediate-band solar cells using deep-level transient spectroscopy (DLTS) technique

    Al Saqri, Noor alhuda; Felix, Jorlandio F.; Aziz, Mohsin; Kunets, Vasyl P.; Jameel, Dler Adil; Taylor, David; Henini, M.; Abd El-sadek, Mahmmoud S.; Furrow, Colin; Ware, Morgan E.; Benamara, Mourad; Mortazavi, Mansour; Salamo, Gregory

    2016-01-01

    InGaAs quantum wire (QWr) intermediate-band solar cell based nanostructures grown by molecular beam epitaxy are studied. The electrical and interface properties of these solar cell devices, as determined by current–voltage (I–V) and capacitance–voltage (C-V) techniques, were found to change with temperature over a wide range of 20–340 K. The electron and hole traps present in these devices have been investigated using deep-level transient spectroscopy (DLTS). The DLTS results showed that the ...

  14. The evolving UK strategy for the management of intermediate level waste to enable disposal to a deep geological repository - a UKAEA/BNFL/NIREX perspective

    Wratten, A.J.; Allan, D.F.; Palmer, J.D.

    1996-01-01

    The objective of this paper is to describe the development of BNFL's and UKAEA's strategies for managing Intermediate Level Waste (ILW) against the background of the evolving national strategy. The impact of the loss of the sea disposal route is addressed together with the challenge of designing waste conditioning plants in parallel with the evolving technical specification for the Nirex deep repository. What has been achieved and is Planned in terms of plant provisioning is described, together with the lessons that have been learned in striving to achieve optimum design solutions. (author)

  15. Identification of nitrogen- and host-related deep-level traps in n-type GaNAs and their evolution upon annealing

    Gelczuk, Ł.; Kudrawiec, R.; Henini, M.

    2014-01-01

    Deep level traps in as-grown and annealed n-GaNAs layers (doped with Si) of various nitrogen concentrations (N = 0.2%, 0.4%, 0.8%, and 1.2%) were investigated by deep level transient spectroscopy. In addition, optical properties of GaNAs layers were studied by photoluminescence and contactless electroreflectance. The identification of N- and host-related traps has been performed on the basis of band gap diagram [Kudrawiec, Appl. Phys. Lett. 101, 082109 (2012)], which assumes that the activation energy of electron traps of the same microscopic nature decreases with the rise of nitrogen concentration in accordance with the N-related shift of the conduction band towards trap levels. The application of this diagram has allowed to investigate the evolution of donor traps in GaNAs upon annealing. In general, it was observed that the concentration of N- and host-related traps decreases after annealing and PL improves very significantly. However, it was also observed that some traps are generated due to annealing. It explains why the annealing conditions have to be carefully optimized for this material system.

  16. Quantum capacitance of the armchair-edge graphene nanoribbon

    Home; Journals; Pramana – Journal of Physics; Volume 81; Issue 2. Quantum capacitance of the ... Abstract. The quantum capacitance, an important parameter in the design of nanoscale devices, is derived for armchair-edge single-layer graphene nanoribbon with semiconducting property. The quantum capacitance ...

  17. Deep Vein Thrombosis

    OWNER

    Deep Vein Thrombosis: Risk Factors and Prevention in Surgical Patients. Deep Vein ... preventable morbidity and mortality in hospitalized surgical patients. ... the elderly.3,4 It is very rare before the age ... depends on the risk level; therefore an .... but also in the post-operative period. ... is continuing uncertainty regarding.

  18. Bivariate quadratic method in quantifying the differential capacitance and energy capacity of supercapacitors under high current operation

    Goh, Chin-Teng; Cruden, Andrew

    2014-11-01

    Capacitance and resistance are the fundamental electrical parameters used to evaluate the electrical characteristics of a supercapacitor, namely the dynamic voltage response, energy capacity, state of charge and health condition. In the British Standards EN62391 and EN62576, the constant capacitance method can be further improved with a differential capacitance that more accurately describes the dynamic voltage response of supercapacitors. This paper presents a novel bivariate quadratic based method to model the dynamic voltage response of supercapacitors under high current charge-discharge cycling, and to enable the derivation of the differential capacitance and energy capacity directly from terminal measurements, i.e. voltage and current, rather than from multiple pulsed-current or excitation signal tests across different bias levels. The estimation results the author achieves are in close agreement with experimental measurements, within a relative error of 0.2%, at various high current levels (25-200 A), more accurate than the constant capacitance method (4-7%). The archival value of this paper is the introduction of an improved quantification method for the electrical characteristics of supercapacitors, and the disclosure of the distinct properties of supercapacitors: the nonlinear capacitance-voltage characteristic, capacitance variation between charging and discharging, and distribution of energy capacity across the operating voltage window.

  19. Circuit and Measurement Technique for Radiation Induced Drift in Precision Capacitance Matching

    Prasad, Sudheer; Shankar, Krishnamurthy Ganapathy

    2013-04-01

    In the design of radiation tolerant precision ADCs targeted for space market, a matched capacitor array is crucial. The drift of capacitance ratios due to radiation should be small enough not to cause linearity errors. Conventional methods for measuring capacitor matching may not achieve the desired level of accuracy due to radiation induced gain errors in the measurement circuits. In this work, we present a circuit and method for measuring capacitance ratio drift to a very high accuracy (<; 1 ppm) unaffected by radiation levels up to 150 krad.

  20. Optical and magnetic resonance signatures of deep levels in semi-insulating 4H SiC

    Carlos, W.E.; Glaser, E.R.; Shanabrook, B.V.

    2003-01-01

    We have studied semi-insulating (SI) 4H SiC grown by physical vapor transport (PVT) and by high-temperature chemical vapor deposition (HTCVD) using electron paramagnetic resonance (EPR) and infrared photoluminescence (IR-PL) to better understand the defect(s) responsible for the SI behavior. Although intrinsic defects such as the isolated carbon vacancy and in some cases the isolated Si vacancies have previously been observed by EPR in undoped SI SiC, their concentrations are an order of magnitude too low to be responsible for the SI behavior. We are able to observe the EPR signature of the carbon vacancy-carbon antisite pair (V C -C Si ) pair defect in an excited state of its 2+ charge state in all PVT samples and some HTCVD samples. We also establish the IR-PL signature of this EPR center as the UD2 spectrum - a set of four sharp lines between 1.1 and 1.15 eV previously observed by Magnusson et al. in neutron-irradiated 4H-SiC. We also observe the UD1 line, a pair of sharp IR-PL lines at ∼1.06 eV and UD3, a single sharp line at ∼1.36 eV. We propose a simple model for the SI behavior in material in which the (V C -C Si ) pair defect is the dominant deep defect

  1. A preliminary study on the suitability of host rocks for deep geological disposal of high level radioactive waste in Korea

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Park, Byung Yun; Koh, Young Kown

    2000-02-01

    It is expected that the key issues are listed as the disposal concept, reference disposal system and other relevant technical development for the deep geological disposal of HLW in each country. First above all, however, the preferred host rocks should be suggested prior execution of these activities. And, it is desirable to be reviewed and proposed some host rocks representative its country. For the reviewing of host rocks in Korean peninsula, several issues were considered such as the long-term geological stability, fracture system, surface and groundwater system and geochemical characteristics in peninsula. The three rock types such as plutonic rocks, crystalline gneisses and massive volcanic rocks were suggested as the preferred host rocks for the R and D of HLW disposal based on the upper stated information. In the following stages, it is suggested that these preferred host rocks would be made an object of all relevant R and D activities for HLW disposal. And, many references for these geologic medium should be characterized and constructed various technical development for the Korean reference disposal system.

  2. A preliminary study on the suitability of host rocks for deep geological disposal of high level radioactive waste in Korea

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Park, Byung Yun; Koh, Young Kown

    2000-02-01

    It is expected that the key issues are listed as the disposal concept, reference disposal system and other relevant technical development for the deep geological disposal of HLW in each country. First above all, however, the preferred host rocks should be suggested prior execution of these activities. And, it is desirable to be reviewed and proposed some host rocks representative its country. For the reviewing of host rocks in Korean peninsula, several issues were considered such as the long-term geological stability, fracture system, surface and groundwater system and geochemical characteristics in peninsula. The three rock types such as plutonic rocks, crystalline gneisses and massive volcanic rocks were suggested as the preferred host rocks for the R and D of HLW disposal based on the upper stated information. In the following stages, it is suggested that these preferred host rocks would be made an object of all relevant R and D activities for HLW disposal. And, many references for these geologic medium should be characterized and constructed various technical development for the Korean reference disposal system

  3. Persistent photoconductivity in AlGaN/GaN heterojunction channels caused by the ionization of deep levels in the AlGaN barrier layer

    Murayama, H.; Akiyama, Y.; Niwa, R.; Sakashita, H.; Sakaki, H.; Kachi, T.; Sugimoto, M.

    2013-01-01

    Time-dependent responses of drain current (I d ) in an AlGaN/GaN HEMT under UV (3.3 eV) and red (2.0 eV) light illumination have been studied at 300 K and 250 K. UV illumination enhances I d by about 10 %, indicating that the density of two-dimensional electrons is raised by about 10 12 cm −2 . When UV light is turned off at 300 K, a part of increased I d decays quickly but the other part of increment is persistent, showing a slow decay. At 250 K, the majority of increment remains persistent. It is found that such a persistent increase of I d at 250 K can be partially erased by the illumination of red light. These photo-responses are explained by a simple band-bending model in which deep levels in the AlGaN barrier get positively charged by the UV light, resulting in a parabolic band bending in the AlGaN layer, while some potion of those deep levels are neutralized by the red light

  4. Compressed magnetic flux amplifier with capacitive load

    Stuetzer, O.M.

    1980-03-01

    A first-order analysis is presented for a compressed magnetic flux (CMF) current amplifier working into a load with a capacitive component. Since the purpose of the investigation was to gain a general understanding of the arrangement, a number of approximations and limitations were accepted. The inductance of the transducer varies with time; the inductance/resistance/capacitance (LRC) circuit therefore is parametric and solutions are different for the stable regime (high C), the oscillation regime (low C), and the transition case. Solutions and performance depend strongly on circuit boundary conditions, i.e., energization of the circuit by either an injected current or by an applied capacitor charge. The behavior of current and energy amplification for the various cases are discussed in detail. A number of experiments with small CMF devices showed that the first-order theory presented predicts transducer performance well in the linear regime

  5. Locating Depots for Capacitated Vehicle Routing

    Gørtz, Inge Li; Nagarajan, Viswanath

    2016-01-01

    We study a location-routing problem in the context of capacitated vehicle routing. The input to the k-location capacitated vehicle routing problem (k-LocVRP) consists of a set of demand locations in a metric space and a fleet of k identical vehicles, each of capacity Q. The objective is to locate k...... depots, one for each vehicle, and compute routes for the vehicles so that all demands are satisfied and the total cost is minimized. Our main result is a constant-factor approximation algorithm for k-LocVRP. In obtaining this result, we introduce a common generalization of the k-median and minimum...... spanning tree problems (called k median forest), which might be of independent interest. We give a local-search based (3+ε)-approximation algorithm for k median forest, which leads to a (12+ε)-approximation algorithm for k-LocVRP, for any constant ε>0....

  6. Locating Depots for Capacitated Vehicle Routing

    Gørtz, Inge Li; Nagarajan, Viswanath

    2016-01-01

    depots, one for each vehicle, and compute routes for the vehicles so that all demands are satisfied and the total cost is minimized. Our main result is a constant-factor approximation algorithm for k-LocVRP. In obtaining this result, we introduce a common generalization of the k-median and minimum...... spanning tree problems (called k median forest), which might be of independent interest. We give a local-search based (3+ε)-approximation algorithm for k median forest, which leads to a (12+ε)-approximation algorithm for k-LocVRP, for any constant ε>0.......We study a location-routing problem in the context of capacitated vehicle routing. The input to the k-location capacitated vehicle routing problem (k-LocVRP) consists of a set of demand locations in a metric space and a fleet of k identical vehicles, each of capacity Q. The objective is to locate k...

  7. High Temperature Capacitive Pressure Sensor Employing a SiC Based Ring Oscillator

    Meredith, Roger D.; Neudeck, Philip G.; Ponchak, George E.; Beheim, Glenn M.; Scardelletti, Maximilian; Jordan, Jennifer L.; Chen, Liang-Yu; Spry, David J.; Krawowski, Michael J.; Hunter, Gary W.

    2011-01-01

    In an effort to develop harsh environment electronic and sensor technologies for aircraft engine safety and monitoring, we have used capacitive-based pressure sensors to shift the frequency of a SiC-electronics-based oscillator to produce a pressure-indicating signal that can be readily transmitted, e.g. wirelessly, to a receiver located in a more benign environment. Our efforts target 500 C, a temperature well above normal operating conditions of commercial circuits but within areas of interest in aerospace engines, deep mining applications and for future missions to the Venus atmosphere. This paper reports for the first time a ring oscillator circuit integrated with a capacitive pressure sensor, both operating at 500 C. This demonstration represents a significant step towards a wireless pressure sensor that can operate at 500 C and confirms the viability of 500 C electronic sensor systems.

  8. Radiation effects on the current-voltage and capacitance-voltage characteristics of advanced p-n junction diodes surrounded by shallow trench isolation

    Poyai, A.; Simoen, E.; Claeys, C.; Hayama, K.; Kobayashi, K.; Ohyama, H.

    2002-01-01

    This paper investigates the impact of 20 MeV proton irradiation on the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of different geometry n + -p-well junction diodes surrounded by shallow trench isolation and processed in a 0.18 μm CMOS technology. From I-V characteristics, a higher current damage coefficient was found for the bulk than for the peripheral component. The radiation-induced boron de-activation resulted in a lowering of the p-well doping, which has been derived from high-frequency C-V measurements. This was confirmed by deep level transient spectroscopy (DLTS) analysis, revealing the presence of interstitial boron related radiation defects. As will be demonstrated for the bulk leakage-current damage coefficient, the electric field enhanced generation rate of charge carriers and the radiation-induced boron de-activation should be accounted for properly

  9. Development of a contactless capacitive immunosensor

    Perruche, Brice Emmanuel

    2011-01-01

    In the present work, a label-free, contactless and capacitive immunosensor is developed using impedance spectroscopy, in the aim to perform low-cost immunoassays. Chapter 1 puts this work in perspective with some existing techniques, while a presentation of impedance theory used in this work is carried out in chapter 2. In Chapter 3, numerical simulations using a commercial finite element method software is carried out. The response of coplanar and fa...

  10. Multi-Channel Capacitive Sensor Arrays

    Bingnan Wang

    2016-01-01

    Full Text Available In this paper, multi-channel capacitive sensor arrays based on microstrip band-stop filters are studied. The sensor arrays can be used to detect the proximity of objects at different positions and directions. Each capacitive sensing structure in the array is connected to an inductive element to form resonance at different frequencies. The resonances are designed to be isolated in the frequency spectrum, such that the change in one channel does not affect resonances at other channels. The inductive element associated with each capacitive sensor can be surface-mounted inductors, integrated microstrip inductors or metamaterial-inspired structures. We show that by using metamaterial split-ring structures coupled to a microstrip line, the quality factor of each resonance can be greatly improved compared to conventional surface-mounted or microstrip meander inductors. With such a microstrip-coupled split-ring design, more sensing elements can be integrated in the same frequency spectrum, and the sensitivity can be greatly improved.

  11. Capacitive Structures for Gas and Biological Sensing

    Sapsanis, Christos

    2015-04-01

    The semiconductor industry was benefited by the advances in technology in the last decades. This fact has an impact on the sensors field, where the simple transducer was evolved into smart miniaturized multi-functional microsystems. However, commercially available gas and biological sensors are mostly bulky, expensive, and power-hungry, which act as obstacles to mass use. The aim of this work is gas and biological sensing using capacitive structures. Capacitive sensors were selected due to its design simplicity, low fabrication cost, and no DC power consumption. In the first part, the dominant structure among interdigitated electrodes (IDEs), fractal curves (Peano and Hilbert) and Archimedean spiral was investigated from capacitance density perspective. The investigation consists of geometrical formula calculations, COMSOL Multiphysics simulations and cleanroom fabrication of the capacitors on a silicon substrate. Moreover, low-cost fabrication on flexible plastic PET substrate was conducted outside cleanroom with rapid prototyping using a maskless laser etching. The second part contains the humidity, Volatile Organic compounds (VOCs) and Ammonia sensing of polymers, Polyimide and Nafion, and metal-organic framework (MOF), Cu(bdc)2.xH2O using IDEs and tested in an automated gas setup for experiment control and data extraction. The last part includes the biological sensing of C - reactive protein (CRP) quantification, which is considered as a biomarker of being prone to cardiac diseases and Bovine serum albumin (BSA) protein quantification, which is used as a reference for quantifying unknown proteins.

  12. Micromachined capacitive ultrasonic immersion transducer array

    Jin, Xuecheng

    Capacitive micromachined ultrasonic transducers (cMUTs) have emerged as an attractive alternative to conventional piezoelectric ultrasonic transducers. They offer performance advantages of wide bandwidth and sensitivity that have heretofore been attainable. In addition, micromachining technology, which has benefited from the fast-growing microelectronics industry, enables cMUT array fabrication and electronics integration. This thesis describes the design and fabrication of micromachined capacitive ultrasonic immersion transducer arrays. The basic transducer electrical equivalent circuit is derived from Mason's theory. The effects of Lamb waves and Stoneley waves on cross coupling and acoustic losses are discussed. Electrical parasitics such as series resistance and shunt capacitance are also included in the model of the transducer. Transducer fabrication technology is systematically studied. Device dimension control in both vertical and horizontal directions, process alternatives and variations in membrane formation, via etch and cavity sealing, and metalization as well as their impact on transducer performance are summarized. Both 64 and 128 element 1-D array transducers are fabricated. Transducers are characterized in terms of electrical input impedance, bandwidth, sensitivity, dynamic range, impulse response and angular response, and their performance is compared with theoretical simulation. Various schemes for cross coupling reduction is analyzed, implemented, and verified with both experiments and theory. Preliminary results of immersion imaging are presented using 64 elements 1-D array transducers for active source imaging.

  13. Calculation of secondary capacitance of compact Tesla pulse transformer

    Yu Binxiong; Liu Jinliang

    2013-01-01

    An analytic expression of the secondary capacitance of a compact Tesla pulse transformer is derived. Calculated result by the expression shows that two parts contribute to the secondary capacitance, namely the capacitance between inner and outer magnetic cores and the attached capacitance caused by the secondary winding. The attached capacitance equals to the capacitance of a coaxial line which is as long as the secondary coil, and whose outer and inner diameters are as large as the inner diameter of the outer magnetic and the outer diameter of the inner magnetic core respectively. A circuital model for analyzing compact Tesla transformer is built, and numeric calculation shows that the expression of the secondary capacitance is correct. Besides, a small compact Tesla transformer is developed, and related test is carried out. Test result confirms the calculated results by the expression derived. (authors)

  14. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    Hu, M.; Bai, Y. Z.; Zhou, Z. B.; Li, Z. X.; Luo, J.

    2014-01-01

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided

  15. Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

    Hu, M.; Bai, Y. Z., E-mail: abai@mail.hust.edu.cn; Zhou, Z. B., E-mail: zhouzb@mail.hust.edu.cn; Li, Z. X.; Luo, J. [MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-05-15

    The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

  16. The correlation of the results of capacitance mapping and of sheet resistance mapping in semi-insulating 6H-SiC

    Lin Shenghuang; Chen Zhiming; Liang Peng; Jiang Dong; Xie Huajie; Yang Ying

    2010-01-01

    A combination of complex surface capacitance mapping and sheet resistance mapping is applied to establish the origin of resistance variations on semi-insulating (SI) 6H-SiC substrates. The direct correlation between the capacitance quadrature and the sheet resistance is found in vanadium-doped SI samples. Regions with low capacitance quadrature show high sheet resistance. This indicates, associated with the nonhomogeneity of sheet resistance on the substrate, that the quality of crystallization is not good enough, which also leads to resistivity nonhomogeneity when comparing with different types of deep defects. According to the capacitance mapping, the region with bad crystallization quality has a high radio absorption coefficient. Another correlation is established between the capacitance in-phase and sheet resistance for the vanadium-doped sample. In this sample, the capacitance in-phase map shows not only the surface topography, but also the same distribution trend as the sheet resistance, namely, regions of high capacitance in-phase reveal high sheet resistance.

  17. Estimating Ground-Level PM2.5 by Fusing Satellite and Station Observations: A Geo-Intelligent Deep Learning Approach

    Li, Tongwen; Shen, Huanfeng; Yuan, Qiangqiang; Zhang, Xuechen; Zhang, Liangpei

    2017-12-01

    Fusing satellite observations and station measurements to estimate ground-level PM2.5 is promising for monitoring PM2.5 pollution. A geo-intelligent approach, which incorporates geographical correlation into an intelligent deep learning architecture, is developed to estimate PM2.5. Specifically, it considers geographical distance and spatiotemporally correlated PM2.5 in a deep belief network (denoted as Geoi-DBN). Geoi-DBN can capture the essential features associated with PM2.5 from latent factors. It was trained and tested with data from China in 2015. The results show that Geoi-DBN performs significantly better than the traditional neural network. The out-of-sample cross-validation R2 increases from 0.42 to 0.88, and RMSE decreases from 29.96 to 13.03 μg/m3. On the basis of the derived PM2.5 distribution, it is predicted that over 80% of the Chinese population live in areas with an annual mean PM2.5 of greater than 35 μg/m3. This study provides a new perspective for air pollution monitoring in large geographic regions.

  18. Improved capacitance sensor with variable operating frequency for scanning capacitance microscopy

    Kwon, Joonhyung; Kim, Joonhui; Jeong, Jong-Hwa; Lee, Euy-Kyu; Seok Kim, Yong; Kang, Chi Jung; Park, Sang-il

    2005-01-01

    Scanning capacitance microscopy (SCM) has been gaining attention for its capability to measure local electrical properties in doping profile, oxide thickness, trapped charges and charge dynamics. In many cases, stray capacitance produced by different samples and measurement conditions affects the resonance frequency of a capacitance sensor. The applications of conventional SCM are critically limited by the fixed operating frequency and lack of tunability in its SCM sensor. In order to widen SCM application to various samples, we have developed a novel SCM sensor with variable operating frequency. By performing variable frequency sweep over the band of 160 MHz, the SCM sensor is tuned to select the best and optimized resonance frequency and quality factor for each sample measurement. The fundamental advantage of the new variable frequency SCM sensor was demonstrated in the SCM imaging of silicon oxide nano-crystals. Typical sensitivity of the variable frequency SCM sensor was found to be 10 -19 F/V

  19. Quantum capacitance in topological insulators under strain in a tilted magnetic field

    Tahir, M.

    2012-12-06

    Topological insulators exhibit unique properties due to surface states of massless Dirac fermions with conserved time reversal symmetry. We consider the quantum capacitance under strain in an external tilted magnetic field and demonstrate a minimum at the charge neutrality point due to splitting of the zeroth Landau level. We also find beating in the Shubnikov de Haas oscillations due to strain, which originate from the topological helical states. Varying the tilting angle from perpendicular to parallel washes out these oscillations with a strain induced gap at the charge neutrality point. Our results explain recent quantum capacitance and transport experiments.

  20. Quantum capacitance in topological insulators under strain in a tilted magnetic field

    Tahir, M.; Schwingenschlö gl, Udo

    2012-01-01

    Topological insulators exhibit unique properties due to surface states of massless Dirac fermions with conserved time reversal symmetry. We consider the quantum capacitance under strain in an external tilted magnetic field and demonstrate a minimum at the charge neutrality point due to splitting of the zeroth Landau level. We also find beating in the Shubnikov de Haas oscillations due to strain, which originate from the topological helical states. Varying the tilting angle from perpendicular to parallel washes out these oscillations with a strain induced gap at the charge neutrality point. Our results explain recent quantum capacitance and transport experiments.

  1. Theory of substrate, Zeeman, and electron-phonon interaction effects on the quantum capacitance in graphene

    Tahir, M.; Sabeeh, K.; Schwingenschlö gl, Udo; Shaukat, A.

    2013-01-01

    Since the discovery of graphene, a lot of interest has been attracted by the zeroth Landau level, which has no analog in the conventional two dimensional electron gas. Recently, lifting of the spin and valley degeneracies has been confirmed experimentally by capacitance measurements, while in transport experiments, this is difficult due to the scattering in the device. In this context, we model interaction effects on the quantum capacitance of graphene in the presence of a perpendicular magnetic field, finding good agreement with experiments. We demonstrate that the valley degeneracy is lifted by the substrate and by Kekule distortion, whereas the spin degeneracy is lifted by Zeeman interaction. The two cases can be distinguished by capacitance measurements.

  2. Theory of substrate, Zeeman, and electron-phonon interaction effects on the quantum capacitance in graphene

    Tahir, M.

    2013-12-10

    Since the discovery of graphene, a lot of interest has been attracted by the zeroth Landau level, which has no analog in the conventional two dimensional electron gas. Recently, lifting of the spin and valley degeneracies has been confirmed experimentally by capacitance measurements, while in transport experiments, this is difficult due to the scattering in the device. In this context, we model interaction effects on the quantum capacitance of graphene in the presence of a perpendicular magnetic field, finding good agreement with experiments. We demonstrate that the valley degeneracy is lifted by the substrate and by Kekule distortion, whereas the spin degeneracy is lifted by Zeeman interaction. The two cases can be distinguished by capacitance measurements.

  3. Theory of substrate, Zeeman, and electron-phonon interaction effects on the quantum capacitance in graphene

    Tahir, M.; Sabeeh, K.; Shaukat, A.; Schwingenschlögl, U.

    2013-01-01

    Since the discovery of graphene, a lot of interest has been attracted by the zeroth Landau level, which has no analog in the conventional two dimensional electron gas. Recently, lifting of the spin and valley degeneracies has been confirmed experimentally by capacitance measurements, while in transport experiments, this is difficult due to the scattering in the device. In this context, we model interaction effects on the quantum capacitance of graphene in the presence of a perpendicular magnetic field, finding good agreement with experiments. We demonstrate that the valley degeneracy is lifted by the substrate and by Kekule distortion, whereas the spin degeneracy is lifted by Zeeman interaction. The two cases can be distinguished by capacitance measurements

  4. Characterization of deep level defects in Tl6I4S single crystals by photo-induced current transient spectroscopy

    Peters, J A; Liu, Z; Sebastian, M; Wessels, B W; Im, J; Freeman, A J; Nguyen, S; Kanatzidis, M G

    2015-01-01

    Defect levels in semi-insulating Tl 6 I 4 S single crystals grown by the horizontal Bridgman technique have been characterized using photo-induced current transient spectroscopy (PICTS). These measurements revealed six electron traps located at (0.059  ±  0.007), (0.13  ±  0.012), (0.31  ±  0.074), (0.39  ±  0.019), (0.62  ±  0.110), and (0.597  ±  0.105). These defect levels are attributed to vacancies (V I , V S ) and antisite defects (I S , Tl S , Tl I ) upon comparison to calculations of native defect energy levels using density functional theory and defects recently reported from photoluminescence and photoconductivity measurements. (paper)

  5. Arthropod phylogenetics in light of three novel millipede (myriapoda: diplopoda) mitochondrial genomes with comments on the appropriateness of mitochondrial genome sequence data for inferring deep level relationships.

    Brewer, Michael S; Swafford, Lynn; Spruill, Chad L; Bond, Jason E

    2013-01-01

    Arthropods are the most diverse group of eukaryotic organisms, but their phylogenetic relationships are poorly understood. Herein, we describe three mitochondrial genomes representing orders of millipedes for which complete genomes had not been characterized. Newly sequenced genomes are combined with existing data to characterize the protein coding regions of myriapods and to attempt to reconstruct the evolutionary relationships within the Myriapoda and Arthropoda. The newly sequenced genomes are similar to previously characterized millipede sequences in terms of synteny and length. Unique translocations occurred within the newly sequenced taxa, including one half of the Appalachioria falcifera genome, which is inverted with respect to other millipede genomes. Across myriapods, amino acid conservation levels are highly dependent on the gene region. Additionally, individual loci varied in the level of amino acid conservation. Overall, most gene regions showed low levels of conservation at many sites. Attempts to reconstruct the evolutionary relationships suffered from questionable relationships and low support values. Analyses of phylogenetic informativeness show the lack of signal deep in the trees (i.e., genes evolve too quickly). As a result, the myriapod tree resembles previously published results but lacks convincing support, and, within the arthropod tree, well established groups were recovered as polyphyletic. The novel genome sequences described herein provide useful genomic information concerning millipede groups that had not been investigated. Taken together with existing sequences, the variety of compositions and evolution of myriapod mitochondrial genomes are shown to be more complex than previously thought. Unfortunately, the use of mitochondrial protein-coding regions in deep arthropod phylogenetics appears problematic, a result consistent with previously published studies. Lack of phylogenetic signal renders the resulting tree topologies as suspect

  6. Arthropod phylogenetics in light of three novel millipede (myriapoda: diplopoda mitochondrial genomes with comments on the appropriateness of mitochondrial genome sequence data for inferring deep level relationships.

    Michael S Brewer

    Full Text Available BACKGROUND: Arthropods are the most diverse group of eukaryotic organisms, but their phylogenetic relationships are poorly understood. Herein, we describe three mitochondrial genomes representing orders of millipedes for which complete genomes had not been characterized. Newly sequenced genomes are combined with existing data to characterize the protein coding regions of myriapods and to attempt to reconstruct the evolutionary relationships within the Myriapoda and Arthropoda. RESULTS: The newly sequenced genomes are similar to previously characterized millipede sequences in terms of synteny and length. Unique translocations occurred within the newly sequenced taxa, including one half of the Appalachioria falcifera genome, which is inverted with respect to other millipede genomes. Across myriapods, amino acid conservation levels are highly dependent on the gene region. Additionally, individual loci varied in the level of amino acid conservation. Overall, most gene regions showed low levels of conservation at many sites. Attempts to reconstruct the evolutionary relationships suffered from questionable relationships and low support values. Analyses of phylogenetic informativeness show the lack of signal deep in the trees (i.e., genes evolve too quickly. As a result, the myriapod tree resembles previously published results but lacks convincing support, and, within the arthropod tree, well established groups were recovered as polyphyletic. CONCLUSIONS: The novel genome sequences described herein provide useful genomic information concerning millipede groups that had not been investigated. Taken together with existing sequences, the variety of compositions and evolution of myriapod mitochondrial genomes are shown to be more complex than previously thought. Unfortunately, the use of mitochondrial protein-coding regions in deep arthropod phylogenetics appears problematic, a result consistent with previously published studies. Lack of phylogenetic

  7. Gas temperature of capacitance spark discharge in air

    Ono, Ryo; Nifuku, Masaharu; Fujiwara, Shuzo; Horiguchi, Sadashige; Oda, Tetsuji

    2005-01-01

    Capacitance spark discharge has been widely used for studying the ignition of flammable gas caused by electrostatic discharge. In the present study, the gas temperature of capacitance spark discharge is measured. The gas temperature is an important factor in understanding the electrostatic ignition process because it influences the reaction rate of ignition. Spark discharge is generated in air with a pulse duration shorter than 100 ns. The discharge energy is set to 0.03-1 mJ. The rotational and vibrational temperatures of the N 2 molecule are measured using the emission spectrum of the N 2 second positive system. The rotational and vibrational temperatures are estimated to be 500 and 5000 K, respectively, which are independent of the discharge energy. This result indicates that most of the electron energy is consumed in the excitation of vibrational levels of molecules rather than the heating of the gas. The gas temperature after discharge is also measured by laser-induced fluorescence of OH radicals. It is shown that the gas temperature increases after discharge and reaches approximately 1000 K at 3 μs after discharge. Then the temperature decreases at a rate in the range of 8-35 K/μs depending on the discharge energy

  8. Role of Catecholamine in Tumor Angiogenesis Linked to Capacitance Relaxation Phenomenon

    Guangyue SHI

    2010-08-01

    Full Text Available The present paper deals with the CgA level during metastasis linked with Capacitance relaxation phenomenon in cancer cell. CgA co-stored and correlated by exocytosis with catecholamines is a precursor to peptides that exert feedback regulatory control on catecholamine secretion. It is to be noted that CgA was the most sensitive marker for detecting patients with tumor angiogenesis. The progressive rise in CgA increases with the tumor size and this fact has been correlated with the Capacitance relaxation phenomenon (T. K. Basak, US patent No. 5691178, 1997 in different stages. The experimental results of Capacitance relaxation phenomenon were given as inputs to a model for correlation with the CgA level. This model is a control system model, the output of which is the CgA level. It is to be noted that the model is simulated in MATLAB. The expression of tumorogenisis in prostate and liver is also linked to Capacitance relaxation phenomenon in respect of its correlation with the CgA level.

  9. Majority- and minority-carrier deep level traps in proton-irradiated n+/p-InGaP space solar cells

    Dharmarasu, Nethaji; Yamaguchi, Masafumi; Bourgoin, Jacques C.; Takamoto, Tatsuya; Ohshima, Takeshi; Itoh, Hisayoshi; Imaizumi, Mitsuru; Matsuda, Sumio

    2002-01-01

    We report the properties of observed defects in n + /p-InGaP solar cells created by irradiation of protons of different energies. Three majority (hole) and a minority-carrier traps, labeled respectively as HP1 (E v +0.90±0.05 eV), HP2 (E v +0.73±0.05 eV), H2 (E v +0.55 eV), and EP1 (E c -0.54 eV), were identified using deep level transient spectroscopy. All majority-carrier traps were found to act as recombination centers. While the H2 trap present in the proton-irradiated p-InGaP was found to anneal out by minority-carrier injection, the other traps were not

  10. A current driven capacitively coupled chlorine discharge

    Huang, Shuo; Gudmundsson, J T

    2014-01-01

    The effect of driving current, driving frequency and secondary electrons on capacitively coupled chlorine discharge is systematically investigated using a hybrid approach consisting of a particle-in-cell/Monte Carlo simulation and a volume-averaged global model. The driving current is varied from 20 to 80 A m −2 , the driving frequency is varied from 13.56 to 60 MHz and the secondary electron emission coefficient is varied from 0.0 to 0.4. Key plasma parameters including electron energy probability function, electron heating rate, ion energy and angular distributions are explored and their variations with control parameters are analyzed and compared with other discharges. Furthermore, we extend our study to dual-frequency (DF) capacitively coupled chlorine discharge by adding a low-frequency current source and explore the effect of the low-frequency source on the discharge. The low-frequency current density is increased from 0 to 4 A m −2 . The flux of Cl 2 + ions to the surface increases only slightly while the average energy of Cl 2 + ions to the surface increases almost linearly with increasing low-frequency current, which shows possible independent control of the flux and energy of Cl 2 + ions by varying the low-frequency current in a DF capacitively coupled chlorine discharge. However, the increase in the flux of Cl + ions with increasing low-frequency current, which is mainly due to the increased dissociation fraction of the background gas caused by extra power supplied by the low-frequency source, is undesirable. (paper)

  11. CMOS MEMS capacitive absolute pressure sensor

    Narducci, M; Tsai, J; Yu-Chia, L; Fang, W

    2013-01-01

    This paper presents the design, fabrication and characterization of a capacitive pressure sensor using a commercial 0.18 µm CMOS (complementary metal–oxide–semiconductor) process and postprocess. The pressure sensor is capacitive and the structure is formed by an Al top electrode enclosed in a suspended SiO 2 membrane, which acts as a movable electrode against a bottom or stationary Al electrode fixed on the SiO 2 substrate. Both the movable and fixed electrodes form a variable parallel plate capacitor, whose capacitance varies with the applied pressure on the surface. In order to release the membranes the CMOS layers need to be applied postprocess and this mainly consists of four steps: (1) deposition and patterning of PECVD (plasma-enhanced chemical vapor deposition) oxide to protect CMOS pads and to open the pressure sensor top surface, (2) etching of the sacrificial layer to release the suspended membrane, (3) deposition of PECVD oxide to seal the etching holes and creating vacuum inside the gap, and finally (4) etching of the passivation oxide to open the pads and allow electrical connections. This sensor design and fabrication is suitable to obey the design rules of a CMOS foundry and since it only uses low-temperature processes, it allows monolithic integration with other types of CMOS compatible sensors and IC (integrated circuit) interface on a single chip. Experimental results showed that the pressure sensor has a highly linear sensitivity of 0.14 fF kPa −1 in the pressure range of 0–300 kPa. (paper)

  12. Study the Z-Plane Strip Capacitance

    Parikh, H.; Swain, S.

    2005-01-01

    The BaBaR detector at the Stanford Linear Accelerator Center is currently undergoing an upgrade to improve its muon and neutral hadron detection system. The Resistive Plate Chambers (RPCs) that had been used till now have deteriorated in performance over the past few years and are being replaced by Limited Streamer Tube (LSTs). Each layer of the system consists of a set of up to 10 streamer tube modules which provide one coordinate (φ coordinate) and a single ''Z-plane'' which provides the Z coordinate of the hit. The large area Z-planes (up to 12m 2 ) are 1mm thick and contain 96 copper strips that detect the induced charge from avalanches created in the streamer tube wires. All the Z-planes needed for the upgrade have already been constructed, but only a third of the planes were installed last summer. After installing the 24 Z-planes last year, it was learned that 0.7% of the strips were dead when put inside the detector. This was mainly due to the delicate solder joint between the read-out cable and the strip, and since it is difficult to access or replace the Z-planes inside the detector, it is very important to perform various tests to make sure that the Z-planes will be efficient and effective in the long term. We measure the capacitance between the copper strips and the ground plane, and compare it to the theoretical value that we expect. Instead of measuring the capacitance channel by channel, which would be a very tedious job, we developed a more effective method of measuring the capacitance. Since all the Z-planes were built at SLAC, we also built a smaller 46 cm by 30 cm Z-plane with 12 strips just to see how they were constructed and to gain a better understanding about the solder joints

  13. Distinction between the Poole-Frenkel and tunneling models of electric-field-stimulated carrier emission from deep levels in semiconductors

    Ganichev, S. D.; Ziemann, E.; Prettl, W.; Yassievich, I. N.; Istratov, A. A.; Weber, E. R.

    2000-01-01

    The enhancement of the emission rate of charge carriers from deep-level defects in electric field is routinely used to determine the charge state of the defects. However, only a limited number of defects can be satisfactorily described by the Poole-Frenkel theory. An electric field dependence different from that expected from the Poole-Frenkel theory has been repeatedly reported in the literature, and no unambiguous identification of the charge state of the defect could be made. In this article, the electric field dependencies of emission of carriers from DX centers in Al x Ga 1-x As:Te, Cu pairs in silicon, and Ge:Hg have been studied applying static and terahertz electric fields, and analyzed by using the models of Poole-Frenkel and phonon assisted tunneling. It is shown that phonon assisted tunneling and Poole-Frenkel emission are two competitive mechanisms of enhancement of emission of carriers, and their relative contribution is determined by the charge state of the defect and by the electric-field strength. At high-electric field strengths carrier emission is dominated by tunneling independently of the charge state of the impurity. For neutral impurities, where Poole-Frenkel lowering of the emission barrier does not occur, the phonon assisted tunneling model describes well the experimental data also in the low-field region. For charged impurities the transition from phonon assisted tunneling at high fields to Poole-Frenkel effect at low fields can be traced back. It is suggested that the Poole-Frenkel and tunneling models can be distinguished by plotting logarithm of the emission rate against the square root or against the square of the electric field, respectively. This analysis enables one to unambiguously determine the charge state of a deep-level defect. (c) 2000 The American Physical Society

  14. Current and capacitance measurements as a fast diagnostic tool for evaluation of semiconductor parameters

    Kemmer, J; Krause, N; Krieglmeyer, C; Yang Yi

    2000-01-01

    A fast qualitative method is described for evaluation of semiconductor parameters by analyzing both the capacitance/voltage (C/V) and current/voltage (I/V) characteristics of pn- or Schottky-diodes, which are fabricated on the material under investigation. The method is applied for measurement of recombination and generation lifetimes of minority charge carriers and for determination of doping profiles and distribution of active generation/recombination (G/R) centers after irradiation with Am-alpha particles and deep phosphorus implantation. Measurements on epitaxial silicon result in doping profiles and distributions of active impurities within the epi-layer.

  15. Understanding the Capacitance of PEDOT:PSS

    Volkov, Anton V.; Wijeratne, Kosala; Mitraka, Evangelia

    2017-01-01

    Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is the most studied and explored mixed ion-electron conducting polymer system. PEDOT:PSS is commonly included as an electroactive conductor in various organic devices, e.g., supercapacitors, displays, transistors, and energy......-converters. In spite of its long-term use as a material for storage and transport of charges, the fundamentals of its bulk capacitance remain poorly understood. Generally, charge storage in supercapacitors is due to formation of electrical double layers or redox reactions, and it is widely accepted that PEDOT...

  16. Spectral response analysis of PVDF capacitive sensors

    Reyes-Ramírez, B.; García-Segundo, C.; García-Valenzuela, A.

    2013-06-01

    We investigate the spectral response to ultrasound waves in water of low-noise capacitive sensors based on PVDF polymer piezoelectric films. First, we analyze theoretically the mechanical-to-electrical transduction as a function of the frequency of ultrasonic signals and derive an analytic expression of the sensor's transfer function. Then we present experimental results of the frequency response of a home-made PDVF in water to test signals from 1 to 20 MHz induced by a commercial hydrophone powered by a signal generator and compare with our theoretical model.

  17. Capacitive tool standoff sensor for dismantlement tasks

    Schmitt, D.J.; Weber, T.M.; Liu, J.C.

    1996-01-01

    A capacitive sensing technology has been applied to develop a Standoff Sensor System for control of robotically deployed tools utilized in Decontamination and Dismantlement (D and D) activities. The system combines four individual sensor elements to provide non-contact, multiple degree-of-freedom control of tools at distances up to five inches from a surface. The Standoff Sensor has been successfully integrated to a metal cutting router and a pyrometer, and utilized for real-time control of each of these tools. Experiments demonstrate that the system can locate stationary surfaces with a repeatability of 0.034 millimeters

  18. The inventory model for feasibility studies of a deep geological disposal for high level and long lived waste

    Dutzer, M.; Lagrange, M.H.; Porcher, J.B.; Chupeau, J.

    2001-01-01

    A detailed inventory of high level and long lived waste packages was established to perform studies for the feasibility of an underground repository. This inventory takes into account existing conditioned waste, unconditioned waste and arisings generated by existing facilities. Grouping of waste package sorts in package types is done regarding relevant characteristics that determine the design of disposal vaults. The radiological content of each package type is derived from calculations of nuclear interactions inside the reactors, from the distribution of the nuclides in the different package types; it is cross-checked with available data on waste sorts. (author)

  19. Study on effective MOSFET channel length extracted from gate capacitance

    Tsuji, Katsuhiro; Terada, Kazuo; Fujisaka, Hisato

    2018-01-01

    The effective channel length (L GCM) of metal-oxide-semiconductor field-effect transistors (MOSFETs) is extracted from the gate capacitances of actual-size MOSFETs, which are measured by charge-injection-induced-error-free charge-based capacitance measurement (CIEF CBCM). To accurately evaluate the capacitances between the gate and the channel of test MOSFETs, the parasitic capacitances are removed by using test MOSFETs having various channel sizes and a source/drain reference device. A strong linear relationship between the gate-channel capacitance and the design channel length is obtained, from which L GCM is extracted. It is found that L GCM is slightly less than the effective channel length (L CRM) extracted from the measured MOSFET drain current. The reason for this is discussed, and it is found that the capacitance between the gate electrode and the source and drain regions affects this extraction.

  20. [Homocysteine levels and polymorphisms of MTHFR and CBS genes in Colombian patients with superficial and deep venous thrombosis].

    Ayala, Claudia; García, Reggie; Cruz, Edith; Prieto, Karol; Bermúdez, Marta

    2010-01-01

    Thrombosis develops when the hemostatic system is incorrectly activated due to the unbalance between procoagulant, anticoagulant and fibrinolytic mechanisms allowing the formation of a clot within a blood vessel. The risk factors of this pathology can be acquired or can be genetic. To analyze in a Colombian population with diagnosis of venous thrombosis, lipid profile, glucose and homocystein levels, to calculate the alleles and genotypic frequencies of polymorphisms c.699 C>T, c.1080 C>T, c.844ins68 of the cystathionine ß synthase and the c.677 C>T of the methylenetetrahydrofolate reductase (MTHFR) genes. Thirty three patients and their controls were studied. The biochemical test was carried out by colorimetric methods and immunoassay. In this survey we used the restriction fragments longitude polymorphism (RLFP) technique to identify the polymorphisms mentioned. The association study was performed through the chi square test. We confirmed that gene alterations increase risk for pathology; we found statistically significant differences in the group with hypercholesterolemia in presence of the polymorphism c.699 C>T in the CBS gene, showing a protective effect in the individuals carrying this genetic variation. Likewise, we found a statistical trend for an eventual protective effect of the CBS c.844ins68 polymorphism to venous thrombotic disease. There were not any statistically significant differences in homocystein levels between cases and controls; nevertheless, the variability in the plasma concentrations was greater in the group of cases.

  1. Transport of a solute pulse through the bentonite barrier of deep geological high-level waste storage facilities in granite

    Cormenzana Lopez, J.L.; Alonso Diaz-Teran, J.; Gonzalez- Herranz, E.

    1997-01-01

    Spain like Sweden, Finland, Canada and other countries has opted for an open nuclear fuel cycle, and to store the unreprocessed spent fuel in a stable geological formation. Sweden, Finland and Canada have chosen granite rock for their high-level waste storage facilities. Their Performance Assessment of disposal systems have all obtained to the same result. The greatest annual doses are caused by I 129 in the gap between the fuel rods and the cladding. The reference concept for the Spanish high-level waste storage facility in granite provides for final storage in a granite mass at a depth of 500 m in carbon steel capsules in horizontal tunnels surrounded by a bentonite buffer. It the capsule fails due to generalised corrosion, an not giving credit for the cladding, the I 129 and other radionuclides in the gap would pass immediately into the surrounding water. This paper describes the modelling of the transport of the solute through the bentonite around the capsule to determine the fraction that crosses the bentonite each year. It also analyses the sensitivity of the results to the boundary condition adopted and changes in the values of the relevant parameters. (Author)

  2. The Prediction of the Risk Level of Pulmonary Embolism and Deep Vein Thrombosis through Artificial Neural Network.

    Agharezaei, Laleh; Agharezaei, Zhila; Nemati, Ali; Bahaadinbeigy, Kambiz; Keynia, Farshid; Baneshi, Mohammad Reza; Iranpour, Abedin; Agharezaei, Moslem

    2016-10-01

    Venous thromboembolism is a common cause of mortality among hospitalized patients and yet it is preventable through detecting the precipitating factors and a prompt diagnosis by specialists. The present study has been carried out in order to assist specialists in the diagnosis and prediction of the risk level of pulmonary embolism in patients, by means of artificial neural network. A number of 31 risk factors have been used in this study in order to evaluate the conditions of 294 patients hospitalized in 3 educational hospitals affiliated with Kerman University of Medical Sciences. Two types of artificial neural networks, namely Feed-Forward Back Propagation and Elman Back Propagation, were compared in this study. Through an optimized artificial neural network model, an accuracy and risk level index of 93.23 percent was achieved and, subsequently, the results have been compared with those obtained from the perfusion scan of the patients. 86.61 percent of high risk patients diagnosed through perfusion scan diagnostic method were also diagnosed correctly through the method proposed in the present study. The results of this study can be a good resource for physicians, medical assistants, and healthcare staff to diagnose high risk patients more precisely and prevent the mortalities. Additionally, expenses and other unnecessary diagnostic methods such as perfusion scans can be efficiently reduced.

  3. The effects of illumination on deep levels observed in as-grown and low-energy electron irradiated high-purity semi-insulating 4H-SiC

    Alfieri, G.; Knoll, L.; Kranz, L.; Sundaramoorthy, V.

    2018-05-01

    High-purity semi-insulating 4H-SiC can find a variety of applications, ranging from power electronics to quantum computing applications. However, data on the electronic properties of deep levels in this material are scarce. For this reason, we present a deep level transient spectroscopy study on HPSI 4H-SiC substrates, both as-grown and irradiated with low-energy electrons (to displace only C-atoms). Our investigation reveals the presence of four deep levels with activation energies in the 0.4-0.9 eV range. The concentrations of three of these levels increase by at least one order of magnitude after irradiation. Furthermore, we analyzed the behavior of these traps under sub- and above-band gap illumination. The nature of the traps is discussed in the light of the present data and results reported in the literature.

  4. Dispersion capacitive de l'interface H2SO4/Pt Capacitive dispersion ...

    Administrateur

    Département de Physique, Faculté des Sciences Exactes. Université des .... d'un comportement idéal de la capacité. Au vu .... Figure 2 : Photographie de la cellule Pt/0,5 MH2SO4 (fabriquée par Verre-Lab Constantine) plongée dans un bain.

  5. Revised shallow and deep water-level and storage-volume changes in the Equus Beds Aquifer near Wichita, Kansas, predevelopment to 1993

    Hansen, Cristi V.; Lanning-Rush, Jennifer L.; Ziegler, Andrew C.

    2013-01-01

    credits from the Equus Beds aquifer by the city of Wichita. The 1993 water levels correspond to the lowest recorded levels and largest storage declines since 1940. Revised and new water-level maps of shallow and deep layers were developed to better represent the general condition of the aquifer. Only static water levels were used to better represent the general condition of the aquifer and comply with Wichita’s ASR permits. To ensure adequate data density, the January 1993 period was expanded to October 1992 through February 1993. Static 1993 water levels from the deep aquifer layer of the Equus Beds aquifer possibly could be used as the lower baseline for regulatory purposes. Previously, maps of water-level changes used to estimate the storage-volume changes included a combination of static (unaffected by pumping or nearby pumping) and stressed (affected by pumping or nearby pumping) water levels from wells. Some of these wells were open to the shallow aquifer layer and some were open to the deep aquifer layer of the Equus Beds aquifer. In this report, only static water levels in the shallow aquifer layer were used to determine storage-volume changes. The effects on average water-level and storage-volume change from the use of mixed, stressed water levels and a specific yield of 0.20 were compared to the use of static water levels in the shallow aquifer and a specific yield of 0.15. This comparison indicates that the change in specific yield causes storage-volume changes to decrease about 25 percent, whereas the use of static water levels in the shallow aquifer layer causes an increase of less than 4 percent. Use of a specific yield of 0.15 will result in substantial decreases in the amount of storage-volume change compared to those reported previously that were calculated using a specific yield of 0.20. Based on these revised water-level maps and computations, the overall decline and change in storage from predevelopment to 1993 represented a loss in storage of about

  6. Accurate sizing of supercapacitors storage system considering its capacitance variation.

    Trieste , Sony; Bourguet , Salvy; Olivier , Jean-Christophe; Loron , Luc; Le Claire , Jean-Claude

    2011-01-01

    International audience; This paper highlights the energy errors made for the design of supercapacitors used as a main energy source. First of all, the paper presents the two definitions of capacitance of a capacitance-voltage dependent material. The number of supercapacitors is important for the application purchasing cost. That is why the paper introduces an analytical model and an electrical model along with an identification method for the capacitance variation. This variation is presented...

  7. Carrier Statistics and Quantum Capacitance Models of Graphene Nanoscroll

    M. Khaledian

    2014-01-01

    schematic perfect scroll-like Archimedes spiral. The DOS model was derived at first, while it was later applied to compute the carrier concentration and quantum capacitance model. Furthermore, the carrier concentration and quantum capacitance were modeled for both degenerate and nondegenerate regimes, along with examining the effect of structural parameters and chirality number on the density of state and carrier concentration. Latterly, the temperature effect on the quantum capacitance was studied too.

  8. Programmable differential capacitance-to-voltage converter for MEMS accelerometers

    Royo, G.; Sánchez-Azqueta, C.; Gimeno, C.; Aldea, C.; Celma, S.

    2017-05-01

    Capacitive MEMS sensors exhibit an excellent noise performance, high sensitivity and low power consumption. They offer a huge range of applications, being the accelerometer one of its main uses. In this work, we present the design of a capacitance-to-voltage converter in CMOS technology to measure the acceleration from the capacitance variations. It is based on a low-power, fully-differential transimpedance amplifier with low input impedance and a very low input noise.

  9. Response to capacitating stimuli indicates extender-related differences in boar sperm function.

    Schmid, S; Henning, H; Petrunkina, A M; Weitze, K F; Waberski, D

    2013-10-01

    Spermatozoa, especially those of the porcine species, are highly susceptible to in vitro chilling and ageing. Extenders are continuously developed to protect boar spermatozoa from chilling injury. New semen extenders and other modified preservation strategies require sensitive testing for essential sperm functions. The key process on the pathway of fertilization is capacitation. The aim of the present study was to examine whether the specific response to capacitating stimuli is sensitive enough to indicate different preservation capacities of extenders during hypothermic storage of boar spermatozoa. Semen was diluted in Beltsville Thawing Solution (BTS) and Androstar Plus and kept for 3 h at 22°C or stored at 17°C, 10°C, and 5°C. Semen was analyzed at 24 and 96 h of storage. Motility and membrane integrity remained at high levels, except for lower values when stored in BTS at 5°C. Washed subsamples were incubated in capacitating medium (Tyrode) and control medium and were assessed for intracellular calcium concentration and integrity of plasma membranes using a flow cytometer. On the basis of the loss of low-calcium live cells in a kinetic approach, the specific response to capacitation stimuli was determined. There was a higher loss of response in semen stored hypothermically in the standard extender BTS compared to Androstar Plus. Assessment of the extent of phospholipid disorder under capacitating and control conditions by use of merocyanine staining did not reveal any significant extender-related differences. A field insemination trial with 778 sows was performed to relate in vitro results to fertility. Fertility parameters did not differ in semen stored up to 48 h at 10°C in Androstar Plus compared to controls stored at 17°C in BTS. In conclusion, assessment of specific reactivity to capacitating stimuli appears to be a sensitive tool for detection of extender-dependent alterations in functionality of chilled boar spermatozoa.

  10. Deep frying

    Koerten, van K.N.

    2016-01-01

    Deep frying is one of the most used methods in the food processing industry. Though practically any food can be fried, French fries are probably the most well-known deep fried products. The popularity of French fries stems from their unique taste and texture, a crispy outside with a mealy soft

  11. Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean

    A. Yool

    2013-09-01

    Full Text Available Most future projections forecast significant and ongoing climate change during the 21st century, but with the severity of impacts dependent on efforts to restrain or reorganise human activity to limit carbon dioxide (CO2 emissions. A major sink for atmospheric CO2, and a key source of biological resources, the World Ocean is widely anticipated to undergo profound physical and – via ocean acidification – chemical changes as direct and indirect results of these emissions. Given strong biophysical coupling, the marine biota is also expected to experience strong changes in response to this anthropogenic forcing. Here we examine the large-scale response of ocean biogeochemistry to climate and acidification impacts during the 21st century for Representative Concentration Pathways (RCPs 2.6 and 8.5 using an intermediate complexity global ecosystem model, MEDUSA-2.0. The primary impact of future change lies in stratification-led declines in the availability of key nutrients in surface waters, which in turn leads to a global decrease (1990s vs. 2090s in ocean productivity (−6.3%. This impact has knock-on consequences for the abundance of the low trophic level biogeochemical actors modelled by MEDUSA-2.0 (−5.8%, and these would be expected to similarly impact higher trophic level elements such as fisheries. Related impacts are found in the flux of organic material to seafloor communities (−40.7% at 1000 m, and in the volume of ocean suboxic zones (+12.5%. A sensitivity analysis removing an acidification feedback on calcification finds that change in this process significantly impacts benthic communities, suggesting that a~better understanding of the OA-sensitivity of calcifying organisms, and their role in ballasting sinking organic carbon, may significantly improve forecasting of these ecosystems. For all processes, there is geographical variability in change – for instance, productivity declines −21% in the Atlantic and increases +59% in

  12. Optimization of the coplanar interdigital capacitive sensor

    Huang, Yunzhi; Zhan, Zheng; Bowler, Nicola

    2017-02-01

    Interdigital capacitive sensors are applied in nondestructive testing and material property characterization of low-conductivity materials. The sensor performance is typically described based on the penetration depth of the electric field into the sample material, the sensor signal strength and its sensitivity. These factors all depend on the geometry and material properties of the sensor and sample. In this paper, a detailed analysis is provided, through finite element simulations, of the ways in which the sensor's geometrical parameters affect its performance. The geometrical parameters include the number of digits forming the interdigital electrodes and the ratio of digit width to their separation. In addition, the influence of the presence or absence of a metal backplane on the sample is analyzed. Further, the effects of sensor substrate thickness and material on signal strength are studied. The results of the analysis show that it is necessary to take into account a trade-off between the desired sensitivity and penetration depth when designing the sensor. Parametric equations are presented to assist the sensor designer or nondestructive evaluation specialist in optimizing the design of a capacitive sensor.

  13. Design of electrical capacitance tomography sensors

    Yang, Wuqiang

    2010-01-01

    Electrical capacitance tomography (ECT) has been developed since the late 1980s for visualization and measurement of a permittivity distribution in a cross section using a multi-electrode capacitance sensor. While the hardware and image reconstruction algorithms for ECT have been published extensively and the topics have been reviewed, few papers have been published to discuss ECT sensors and the design issues, which are crucial for a specific application. This paper will briefly discuss the principles of ECT sensors, but mostly will address key issues for ECT sensor design, with reference to some existing ECT sensors as a good understanding of the key issues would help optimization of the design of ECT sensors. The key issues to be discussed include the number and length of electrodes, the use of external and internal electrodes, implications of wall thickness, earthed screens (including the outer screen, axial end screens and radial screens), driven guard electrodes, dealing with high temperature and high pressure, twin planes for velocity measurement by cross correlation and limitations in sensor diameter. While conventional ECT sensors are circular with the electrodes in a single plane or in twin planes, some non-conventional ECT sensors, such as square, conical and 3D sensors, will also be discussed. As a practical guidance, the procedure to fabricate an ECT sensor will be given. In the end are summary and discussion on future challenges, including re-engineering of ECT sensors. (topical review)

  14. Deep learning

    Goodfellow, Ian; Courville, Aaron

    2016-01-01

    Deep learning is a form of machine learning that enables computers to learn from experience and understand the world in terms of a hierarchy of concepts. Because the computer gathers knowledge from experience, there is no need for a human computer operator to formally specify all the knowledge that the computer needs. The hierarchy of concepts allows the computer to learn complicated concepts by building them out of simpler ones; a graph of these hierarchies would be many layers deep. This book introduces a broad range of topics in deep learning. The text offers mathematical and conceptual background, covering relevant concepts in linear algebra, probability theory and information theory, numerical computation, and machine learning. It describes deep learning techniques used by practitioners in industry, including deep feedforward networks, regularization, optimization algorithms, convolutional networks, sequence modeling, and practical methodology; and it surveys such applications as natural language proces...

  15. Application of Deep Learning and Supervised Learning Methods to Recognize Nonlinear Hidden Pattern in Water Stress Levels from Spatiotemporal Datasets across Rural and Urban US Counties

    Eisenhart, T.; Josset, L.; Rising, J. A.; Devineni, N.; Lall, U.

    2017-12-01

    In the wake of recent water crises, the need to understand and predict the risk of water stress in urban and rural areas has grown. This understanding has the potential to improve decision making in public resource management, policy making, risk management and investment decisions. Assuming an underlying relationship between urban and rural water stress and observable features, we apply Deep Learning and Supervised Learning models to uncover hidden nonlinear patterns from spatiotemporal datasets. Results of interest includes prediction accuracy on extreme categories (i.e. urban areas highly prone to water stress) and not solely the average risk for urban or rural area, which adds complexity to the tuning of model parameters. We first label urban water stressed counties using annual water quality violations and compile a comprehensive spatiotemporal dataset that captures the yearly evolution of climatic, demographic and economic factors of more than 3,000 US counties over the 1980-2010 period. As county-level data reporting is not done on a yearly basis, we test multiple imputation methods to get around the issue of missing data. Using Python libraries, TensorFlow and scikit-learn, we apply and compare the ability of, amongst other methods, Recurrent Neural Networks (testing both LSTM and GRU cells), Convolutional Neural Networks and Support Vector Machines to predict urban water stress. We evaluate the performance of those models over multiple time spans and combine methods to diminish the risk of overfitting and increase prediction power on test sets. This methodology seeks to identify hidden nonlinear patterns to assess the predominant data features that influence urban and rural water stress. Results from this application at the national scale will assess the performance of deep learning models to predict water stress risk areas across all US counties and will highlight a predominant Machine Learning method for modeling water stress risk using spatiotemporal

  16. Deep Ocean Mineral Supplementation Enhances the Cerebral Hemodynamic Response during Exercise and Decreases Inflammation Postexercise in Men at Two Age Levels

    Ching-Yin Wei

    2017-12-01

    Full Text Available Background: Previous studies have consistently shown that oral supplementation of deep ocean minerals (DOM improves vascular function in animals and enhances muscle power output in exercising humans.Purpose: To examine the effects of DOM supplementation on the cerebral hemodynamic response during physical exertion in young and middle-aged men.Design: Double-blind placebo-controlled crossover studies were conducted in young (N = 12, aged 21.2 ± 0.4 years and middle-aged men (N = 9, aged 46.8 ± 1.4 years. The counter-balanced trials of DOM and Placebo were separated by a 2-week washout period. DOM and Placebo were orally supplemented in drinks before, during, and after cycling exercise. DOM comprises desalinated minerals and trace elements from seawater collected ~618 m below the earth's surface.Methods: Cerebral hemodynamic response (tissue hemoglobin was measured during cycling at 75% VO2max using near infrared spectroscopy (NIRS.Results: Cycling time to exhaustion at 75% VO2max and the associated plasma lactate response were similar between the Placebo and DOM trials for both age groups. In contrast, DOM significantly elevated cerebral hemoglobin levels in young men and, to a greater extent, in middle-aged men compared with Placebo. An increased neutrophil to lymphocyte ratio (NLR was observed in middle-aged men, 2 h after exhaustive cycling, but was attenuated by DOM.Conclusion: Our data suggest that minerals and trace elements from deep oceans possess great promise in developing supplements to increase the cerebral hemodynamic response against a physical challenge and during post-exercise recovery for middle-aged men.

  17. Application of Ga-Al discrimination plots in identification of high strength granitic host rocks for deep geological repository of high level radioactive waste

    Bajpai, R.K.; Narayan, P.K.; Trivedi, R.K.; Purohit, M.K.

    2010-01-01

    The permanent disposal of vitrified high level wastes and in some cases even spent fuel, is being planned in specifically designed and built deep geological repository located in the depth range of 500-600m in appropriate host rock at carefully selected sites. Such facilities are expected to provide very long term isolation and confinement to the disposed waste by means of long term mechanical stability of such structures that results from very high strength and homogeneity of the chosen rock, geochemical compatible environment around the disposed waste and general lack of groundwater. In Indian geological repository development programme, granites have been selected as target host rock and large scale characterization studies have been undertaken to develop database of mineralogy, petrology, geochemistry and rock mechanical characteristics. The paper proposes a new approach for demarcation of high strength homogeneous granite rocks from within an area of about 100 square kilometres wherein a cocktail of granites of different origins with varying rock mass characteristics co exists. The study area is characterised by the presence of A, S and I type granites toughly intermixed. The S type granites are derived from sedimentary parent material and therefore carry relics of parent fabric and at times undigested material with resultant reduction in their strength and increased inhomogeneity. On the other hand I type varieties are derived from igneous parents and are more homogeneous with sufficient strength. The A type granites are emplaced as molten mass in a complete non-tectonic setting with resultant homogeneous compositions, absence of tectonic fabric and very high strength. Besides they are silica rich with less vulnerability to alterations with time. Thus A type granites are most suited for construction of Deep Geological Repository. For developing a geochemical approach for establishing relation between chemical compositions and rock strength parameters, a

  18. Deep sequencing of Brachypodium small RNAs at the global genome level identifies microRNAs involved in cold stress response

    Chong Kang

    2009-09-01

    Full Text Available Abstract Background MicroRNAs (miRNAs are endogenous small RNAs having large-scale regulatory effects on plant development and stress responses. Extensive studies of miRNAs have only been performed in a few model plants. Although miRNAs are proved to be involved in plant cold stress responses, little is known for winter-habit monocots. Brachypodium distachyon, with close evolutionary relationship to cool-season cereals, has recently emerged as a novel model plant. There are few reports of Brachypodium miRNAs. Results High-throughput sequencing and whole-genome-wide data mining led to the identification of 27 conserved miRNAs, as well as 129 predicted miRNAs in Brachypodium. For multiple-member conserved miRNA families, their sizes in Brachypodium were much smaller than those in rice and Populus. The genome organization of miR395 family in Brachypodium was quite different from that in rice. The expression of 3 conserved miRNAs and 25 predicted miRNAs showed significant changes in response to cold stress. Among these miRNAs, some were cold-induced and some were cold-suppressed, but all the conserved miRNAs were up-regulated under cold stress condition. Conclusion Our results suggest that Brachypodium miRNAs are composed of a set of conserved miRNAs and a large proportion of non-conserved miRNAs with low expression levels. Both kinds of miRNAs were involved in cold stress response, but all the conserved miRNAs were up-regulated, implying an important role for cold-induced miRNAs. The different size and genome organization of miRNA families in Brachypodium and rice suggest that the frequency of duplication events or the selection pressure on duplicated miRNAs are different between these two closely related plant species.

  19. Suppression and enhancement of deep level emission of ZnO on Si4+ & V5+ substitution

    Srivastava, T.; Bajpai, G.; Sen, S.

    2018-03-01

    ZnO possess a wide range of tunable properties depending on the type and concentration of dopant. Defects in ZnO due to doped aliovalent ions can generate certain functionalities. Such defects in the lattice do not deteriorate the material properties but actually modifies the material towards infinite number of possibilities. Defects like oxygen vacancies play a significant role in photocatalytic and sensing applications. Depending upon the functionality, defect state of ZnO can be modified by suitable doping. Amount and nature of different dopant has different effect on defect state of ZnO. It depends upon the ionic radii, valence state, chemical stability etc. of the ion doped. Two samples with two different dopants i.e., silicon and vanadium, Zn1-xSixO and Zn1-xVxO, for x=0 & 0.020, were synthesized using solgel method (a citric acid-glycerol route) followed by solid state sintering. A comparison of their optical properties, photoluminescence and UV-Vis spectroscopy, with pure ZnO was studied at room temperature. Silicon doping drastically reduces whereas vanadium doping enhances the green emission as compared with pure ZnO. Suppression and enhancement of defect levels (DLE) is rationalized by the effects of extra charge present on Si4+ & V5+ (in comparison to Zn2+) and formation of new hybrid state (V3d O2p) within bandgap. Reduction of defects in Zn1-xSixO makes it suitable material for opto-electronics application whereas enhancement in defects in Zn1-xVxO makes it suitable material for photocatalytic as well as gas sensing application.

  20. Deep Super Learner: A Deep Ensemble for Classification Problems

    Young, Steven; Abdou, Tamer; Bener, Ayse

    2018-01-01

    Deep learning has become very popular for tasks such as predictive modeling and pattern recognition in handling big data. Deep learning is a powerful machine learning method that extracts lower level features and feeds them forward for the next layer to identify higher level features that improve performance. However, deep neural networks have drawbacks, which include many hyper-parameters and infinite architectures, opaqueness into results, and relatively slower convergence on smaller datase...

  1. MEMS capacitive force sensors for cellular and flight biomechanics

    Sun Yu; Nelson, Bradley J

    2007-01-01

    Microelectromechanical systems (MEMS) are playing increasingly important roles in facilitating biological studies. They are capable of providing not only qualitative but also quantitative information on the cellular, sub-cellular and organism levels, which is instrumental to understanding the fundamental elements of biological systems. MEMS force sensors with their high bandwidth and high sensitivity combined with their small size, in particular, have found a role in this domain, because of the importance of quantifying forces and their effect on the function and morphology of many biological structures. This paper describes our research in the development of MEMS capacitive force sensors that have already demonstrated their effectiveness in the areas of cell mechanics and Drosophila flight dynamics studies. (review article)

  2. Implications of vegetation hydraulic capacitance as an indicator of water stress and drought recovery

    Matheny, A. M.; Bohrer, G.

    2017-12-01

    Above-ground water storage in vegetation plays an integral role in the avoidance of hydraulic impairment to transpiration. New high temporal resolution measurements of dynamic changes in tree hydraulic capacitance are facilitating insights into vegetation water use strategies. Diurnal withdrawal from water storage in leaves, branches, stems, and roots significantly impacts sap flow, stomatal conductance, and transpiration. The ability to store and use water varies based on soil- and root-water availability, tree size, wood vessel anatomy and density, and stomatal response strategy (i.e. isohydricity). We present results from a three-year long study of stem capacitance dynamics in five species in a mixed deciduous forest in Michigan. The site receives 800mm of rainfall annually, but water potential in the well-drained sandy soil nears the permanent wilting point several times annually. We demonstrate radical differences in stored water use between drought tolerant and intolerant species. Red maple, a drought intolerant, isohydric species, showed a strong dependence on stem capacitance for transpiration during both wet and dry periods. Red oak, a more drought hearty, deep rooted, anisohydric species, was much less reliant on withdrawal from water storage during all conditions. During well-watered conditions, withdrawal from storage by red maple was 10 kg day-1, yet storage withdrawal from similarly sized red oaks was 1 kg day-1. Red oaks only drew strongly upon stored water during the driest extremes. Metrics of hydration status derived from capacitance provide a means to explore drought response and recovery. Declines in consecutive days' maximum capacitance indicate an inability to restore lost water and can be used to mark the onset of water stress. Drought recovery can be quantified as the time required for stem water content to return to pre-drought volumes. Capacitance withdrawal and depletion exhibit a clear threshold response to declining soil water

  3. Electronic relaxation of deep bulk trap and interface state in ZnO ceramics

    Yang Yan; Li Sheng-Tao; Ding Can; Cheng Peng-Fei

    2011-01-01

    This paper investigates the electronic relaxation of deep bulk trap and interface state in ZnO ceramics based on dielectric spectra measured in a wide range of temperature, frequency and bias, in addition to the steady state response. It discusses the nature of net current flowing over the barrier affected by interface state, and then obtains temperature-dependent barrier height by approximate calculation from steady I—V (current—voltage) characteristics. Additional conductance and capacitance arising from deep bulk trap relaxation are calculated based on the displacement of the cross point between deep bulk trap and Fermi level under small AC signal. From the resonances due to deep bulk trap relaxation on dielectric spectra, the activation energies are obtained as 0.22 eV and 0.35 eV, which are consistent with the electronic levels of the main defect interstitial Zn and vacancy oxygen in the depletion layer. Under moderate bias, another resonance due to interface relaxation is shown on the dielectric spectra. The DC-like conductance is also observed in high temperature region on dielectric spectra, and the activation energy is much smaller than the barrier height in steady state condition, which is attributed to the displacement current coming from the shallow bulk trap relaxation or other factors. (fluids, plasmas and electric discharges)

  4. Probabilistic safety assessment for a generic deep geological repository for high-level waste and long-lived intermediate-level waste in clay

    Resele, G.; Holocher, J.; Mayer, G.; Hubschwerlen, N.; Niemeyer, M.; Beushausen, M.; Wollrath, J.

    2010-01-01

    Document available in extended abstract form only. In the selection procedure for the search of a final site location for the disposal of radioactive wastes, the comparison and evaluation of different potentially suitable repository systems in different types of host rocks will be an essential and crucial step. Since internationally accepted guidelines on how to perform such quantitative comparisons between repository systems with regard to their long-term safety behaviour are still lacking, in 2007 the German Federal Office for Radiation Protection launched the project 'VerSi' (Vergleichende Sicherheitsanalysen - Comparing Safety Assessments) that aims at the development of a methodology for the comparison of long-term safety assessments. A vital part of the VerSi project is the performance of long-term safety assessments for the comparison of two repository systems. The comparison focuses on a future repository for heat-generating, i.e. high-level and long-lived intermediate-level radioactive wastes in Germany. Rock salt is considered as a potential host rock for such a repository, and one repository system in VerSi is defined similarly to the potential site located in the Gorleben salt dome. Another suitable host rock formation may be clay. A generic location within the lower Cretaceous clays in Northern Germany is therefore chosen for the comparison of safety assessments within the VerSi project. The long-term safety assessment of a repository system for heat-generating radioactive waste at the generic clay location comprises different steps, amongst others: - Identifying the relevant processes in the near-field, in the geosphere and in the biosphere which are relevant for the long-term safety behaviour. - Development of a safety concept for the repository system. - Deduction of scenarios of the long-term evolution of the repository system. - Definition of statistic weights, i. e. the likelihood of occurrence of the scenarios. - Performance of a

  5. The nature of a deformation zone and fault rock related to a recent rockburst at Western Deep Levels Gold Mine, Witwatersrand Basin, South Africa

    Stewart, R. A.; Reimold, W. U.; Charlesworth, E. G.; Ortlepp, W. D.

    2001-07-01

    In August 1998, a major deformation zone was exposed over several metres during mining operations on 87 Level (2463 m below surface) at Western Deep Levels Gold Mine, southwest of Johannesburg, providing a unique opportunity to study the products of a recent rockburst. This zone consists of three shear zones, with dip-slip displacements of up to 15 cm, that are oriented near-parallel to the advancing stope face. Jogs and a highly pulverised, cataclastic 'rock-flour' are developed on the displacement surfaces, and several sets of secondary extensional fractures occur on either side of the shear zones. A set of pinnate (feather) joints intersects the fault surfaces perpendicular to the slip vector. Microscopically, the shear zones consist of two pinnate joint sets that exhibit cataclastic joint fillings; quartz grains display intense intragranular fracturing. Secondary, intergranular extension fractures are associated with the pinnate joints. Extensional deformation is also the cause of the breccia fill of the pinnate joints. The initial deformation experienced by this zone is brittle and tensile, and is related to stresses induced by mining. This deformation has been masked by later changes in the stress field, which resulted in shearing. This deformation zone does not appear to be controlled by pre-existing geological features and, thus, represents a 'burst fracture', which is believed to be related to a seismic event of magnitude ML=2.1 recorded in July 1998, the epicentre of which was located to within 50 m of the study locality.

  6. Effect of deep levels of radiation-induced defects in silicon γ-irradiated Al-V-n-Si structures characteristics

    Buzaneva, E.V.; Vdovichenko, A.D.; Kuznetsov, G.V.; Muntyan, Yu.G.

    1985-01-01

    The effect of high energy γ-quanta irradiation on the mechanism of current transmission in Al-V-N-Si structures employed in Schottky barrier instruments has been investigated. Before irradiation the structures have been annealed in the nitrogen atmosphere at T=500 deg C. The samples have been γ-irradiated on the side of the metall film at T=20 deg C. The irradiation spectrum is continuous, maximum γ-quanta energy 50 MeV, medium one is 20 MeV. The integral flux of γ-quanta, PHIsub(γ) varied from 10 7 to 10 13 quantum/cm -2 . The volt-ampere and volt-farad characteristics have been measred. It is shown that variation of the main electrophysical characteristics of the Al-V-nSi structures upon γ-irradiation is due to deep levels of radiation defects arising in silicon with the energetic position Esub(c)-E=0.38-0.4 eV and Esub(v)+Esub(2)=0.23-0.25 → β, where Esub(c), Esub(v) are energies for the conduction band bottom and the valence band ceiling. In the 77-293 K temperature range the determining range the determining effect on current mission mechanism in irradiated structures is exerted by resonance electron tunnelling with participation of a level with the Esub(c)-Esub(1)=0.38-0.4 eV

  7. As-grown deep-level defects in n-GaN grown by metal-organic chemical vapor deposition on freestanding GaN

    Chen Shang; Ishikawa, Kenji; Hori, Masaru; Honda, Unhi; Shibata, Tatsunari; Matsumura, Toshiya; Tokuda, Yutaka; Ueda, Hiroyuki; Uesugi, Tsutomu; Kachi, Tetsu

    2012-01-01

    Traps of energy levels E c -0.26 and E c -0.61 eV have been identified as as-grown traps in n-GaN grown by metal-organic chemical vapor deposition by using deep level transient spectroscopy of the Schottky contacts fabricated by resistive evaporation. The additional traps of E c -0.13 and E c -0.65 eV have been observed in samples whose contacts are deposited by electron-beam evaporation. An increase in concentration of the E c -0.13 and E c -0.65 eV traps when approaching the interface between the contact and the GaN film supports our argument that these traps are induced by electron-beam irradiation. Conversely, the depth profiles of as-grown traps show different profiles between several samples with increased or uniform distribution in the near surface below 50 nm. Similar profiles are observed in GaN grown on a sapphire substrate. We conclude that the growth process causes these large concentrations of as-grown traps in the near-surface region. It is speculated that the finishing step in the growth process should be an essential issue in the investigation of the surface state of GaN.

  8. Study of silicon-silicon nitride interface properties on planar (1 0 0), planar (1 1 1) and textured surfaces using deep-level transient spectroscopy

    Gong, Chun; Simoen, Eddy; Posthuma, Niels E; Van Kerschaver, Emmanuel; Poortmans, Jef; Mertens, Robert

    2010-01-01

    Deep-level transient spectroscopy (DLTS) has been applied to metal-insulator-semiconductor (MIS) capacitors fabricated on planar (1 0 0), planar (1 1 1) orientations and textured n-type silicon wafers. Low frequency direct plasma-enhanced chemical vapour deposition Si-SiN x interface properties with and without plasma NH 3 pre-treatment, with and without rapid thermal annealing (RTA) have been investigated. It is shown that three different kinds of defect states are identified at the Si-SiN x interface. For the planar (1 0 0) surface, samples with plasma NH 3 pre-treatment plus RTA show the lowest DLTS signals, which suggests the lowest overall interface states density. For planar (1 1 1) Si surfaces, plasma NH 3 pre-treatment and RTA yield a small improvement. With the textured surface, the RTA step improves the surface passivation quality further but no obvious impact is found with plasma NH 3 pre-treatment. Energy-dependent electron capture cross sections were also measured by small-pulse DLTS. The capture cross sections depend strongly on the energy level and decrease towards the conduction band edge.

  9. Fund allocation using capacitated vehicle routing problem

    Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita; Darus, Maslina

    2014-09-01

    In investment fund allocation, it is unwise for an investor to distribute his fund into several assets simultaneously due to economic reasons. One solution is to allocate the fund into a particular asset at a time in a sequence that will either maximize returns or minimize risks depending on the investor's objective. The vehicle routing problem (VRP) provides an avenue to this issue. VRP answers the question on how to efficiently use the available fleet of vehicles to meet a given service demand, subjected to a set of operational requirements. This paper proposes an idea of using capacitated vehicle routing problem (CVRP) to optimize investment fund allocation by employing data of selected stocks in the FTSE Bursa Malaysia. Results suggest that CRVP can be applied to solve the issue of investment fund allocation and increase the investor's profit.

  10. A capacitive bioelectrode for recording electrophysiological signals

    Moreno Garcia, E.; Mujica Ascencio, S.; Rosa Vazquez, J. M.de la; Stolik Isakina, S.

    2012-01-01

    In this paper we describe a gel-free sensor with on-board electrode design, which capacitive couples to the skin to detect the electrical activity in the body. The integrated sensor is manufactured on a standard printed circuit board within 2.2 cm diameter enclosure that can operate through fabric or other insulation. The electrode includes amplification (60db gain) and passive band pass filtering (0.5 to 100 Hz). Active shielding surrounding the sensor plate is used to reduce noise pickup. The input referred noise, measured over the electrode bandwidth is 4 μV rms at 0.2 mm sensor distance, and 16 μV rms at 1.2 mm distance trough two cotton cloths. The bioelectrodes were coupled to the scalp trough hair for EEG signals (with 80 db gain), and coupled to the chest through clothing for ECG signals. The recorded signals show well performance of the designed bielectrode. (Author)

  11. Vertically aligned BCN nanotubes with high capacitance.

    Iyyamperumal, Eswaramoorthi; Wang, Shuangyin; Dai, Liming

    2012-06-26

    Using a chemical vapor deposition method, we have synthesized vertically aligned BCN nanotubes (VA-BCNs) on a Ni-Fe-coated SiO(2)/Si substrate from a melamine diborate precursor. The effects of pyrolysis conditions on the morphology and thermal property of grown nanotubes, as well as the nanostructure and composition of an individual BCN nanotube, were systematically studied. It was found that nitrogen atoms are bonded to carbons in both graphitic and pyridinic forms and that the resultant VA-BCNs grown at 1000 °C show the highest specific capacitance (321.0 F/g) with an excellent rate capability and high durability with respect to nonaligned BCN (167.3 F/g) and undoped multiwalled carbon nanotubes (117.3 F/g) due to synergetic effects arising from the combined co-doping of B and N in CNTs and the well-aligned nanotube structure.

  12. Developments of capacitance stabilised etalon technology

    Bond, R. A.; Foster, M.; Thwaite, C.; Thompson, C. K.; Rees, D.; Bakalski, I. V.; Pereira do Carmo, J.

    2017-11-01

    This paper describes a high-resolution optical filter (HRF) suitable for narrow bandwidth filtering in LIDAR applications. The filter is composed of a broadband interference filter and a narrowband Fabry-Perot etalon based on the capacitance stabilised concept. The key requirements for the HRF were a bandwidth of less than 40 pm, a tuneable range of over 6 nm and a transmission greater than 50%. These requirements combined with the need for very high out-of-band rejection (greater than 50 dB in the range 300 nm to 1200 nm) drive the design of the filter towards a combination of high transmission broadband filter and high performance tuneable, narrowband filter.

  13. Capacitive Neutralization Dialysis for Direct Energy Generation.

    Liu, Yue; Zhang, Yi; Ou-Yang, Wei; Bastos Sales, Bruno; Sun, Zhuo; Liu, Fei; Zhao, Ran

    2017-08-15

    Capacitive neutralization dialysis energy (CNDE) is proposed as a novel energy-harvesting technique that is able to utilize waste acid and alkaline solutions to produce electrical energy. CNDE is a modification based on neutralization dialysis. It was found that a higher NaCl concentration led to a higher open-circuit potential when the concentrations of acid and alkaline solutions were fixed. Upon closing of the circuit, the membrane potential was used as a driving force to move counter ions into the electrical double layers at the electrode-liquid interface, thereby creating an ionic current. Correspondingly, in the external circuit, electrons flow through an external resistor from one electrode to the other, thereby generating electrical energy directly. The influence of external resistances was studied to achieve greater energy extraction, with the maximum output of 110 mW/m 2 obtained by employing an external resistance of 5 Ω together with the AC-coated electrode.

  14. The capacitated team orienteering problem with incomplete service

    Archetti, Claudia; Bianchessi, Nicola; Speranza, M. Grazia

    2013-01-01

    In this paper we study the capacitated version of the Team Orienteering Problem (TOP), that is the Capacitated TOP (CTOP) and the impact of relaxing the assumption that a customer, if served, must be completely served. We prove that the profit collected by the CTOP with Incomplete Service (CTOP-IS)

  15. Clean energy generation using capacitive electrodes in reverse electrodialysis

    Vermaas, David; Bajracharya, S.; Bastos Sales, B.; Saakes, Michel; Hamelers, B.; Nijmeijer, Dorothea C.

    2013-01-01

    Capacitive reverse electrodialysis (CRED) is a newly proposed technology to generate electricity from mixing of salt water and fresh water (salinity gradient energy) by using a membrane pile as in reverse electrodialysis (RED) and capacitive electrodes. The salinity difference between salt water and

  16. Electric field theory and the fallacy of void capacitance

    McAllister, Iain Wilson

    1991-01-01

    The concept of the capacitance of a gaseous void is discussed as applied to electrical insulation science. The most pertinent aspect of the capacitance definition is that of reference to a single-valued potential difference between surfaces. This implies that these surfaces must be surfaces...

  17. Nanoscale capacitance: A quantum tight-binding model

    Zhai, Feng; Wu, Jian; Li, Yang; Lu, Jun-Qiang

    2017-01-01

    Landauer-Buttiker formalism with the assumption of semi-infinite electrodes as reservoirs has been the standard approach in modeling steady electron transport through nanoscale devices. However, modeling dynamic electron transport properties, especially nanoscale capacitance, is a challenging problem because of dynamic contributions from electrodes, which is neglectable in modeling macroscopic capacitance and mesoscopic conductance. We implement a self-consistent quantum tight-binding model to calculate capacitance of a nano-gap system consisting of an electrode capacitance C‧ and an effective capacitance Cd of the middle device. From the calculations on a nano-gap made of carbon nanotube with a buckyball therein, we show that when the electrode length increases, the electrode capacitance C‧ moves up while the effective capacitance Cd converges to a value which is much smaller than the electrode capacitance C‧. Our results reveal the importance of electrodes in modeling nanoscale ac circuits, and indicate that the concepts of semi-infinite electrodes and reservoirs well-accepted in the steady electron transport theory may be not applicable in modeling dynamic transport properties.

  18. A Review of High Voltage Drive Amplifiers for Capacitive Actuators

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

    2012-01-01

    This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail...

  19. Large Capacitance Measurement by Multiple Uses of MBL Charge Sensor

    Lee, Jung Sook; Chae, Min; Kim, Jung Bog

    2010-01-01

    A recent article by Morse described interesting electrostatics experiments using an MBL charge sensor. In this application, the charge sensor has a large capacitance compared to the charged test object, so nearly all charges can be transferred to the sensor capacitor from the capacitor to be measured. However, the typical capacitance of commercial…

  20. Measurement Error Estimation for Capacitive Voltage Transformer by Insulation Parameters

    Bin Chen

    2017-03-01

    Full Text Available Measurement errors of a capacitive voltage transformer (CVT are relevant to its equivalent parameters for which its capacitive divider contributes the most. In daily operation, dielectric aging, moisture, dielectric breakdown, etc., it will exert mixing effects on a capacitive divider’s insulation characteristics, leading to fluctuation in equivalent parameters which result in the measurement error. This paper proposes an equivalent circuit model to represent a CVT which incorporates insulation characteristics of a capacitive divider. After software simulation and laboratory experiments, the relationship between measurement errors and insulation parameters is obtained. It indicates that variation of insulation parameters in a CVT will cause a reasonable measurement error. From field tests and calculation, equivalent capacitance mainly affects magnitude error, while dielectric loss mainly affects phase error. As capacitance changes 0.2%, magnitude error can reach −0.2%. As dielectric loss factor changes 0.2%, phase error can reach 5′. An increase of equivalent capacitance and dielectric loss factor in the high-voltage capacitor will cause a positive real power measurement error. An increase of equivalent capacitance and dielectric loss factor in the low-voltage capacitor will cause a negative real power measurement error.

  1. Capacitive-discharge-pumped copper bromide vapour laser

    Sukhanov, V B; Fedorov, V F; Troitskii, V O; Gubarev, F A; Evtushenko, Gennadii S

    2007-01-01

    A copper bromide vapour laser pumped by a high-frequency capacitive discharge is developed. It is shown that, by using of a capacitive discharge, it is possible to built a sealed off metal halide vapour laser of a simple design allowing the addition of active impurities into the working medium. (letters)

  2. Biasing of Capacitive Micromachined Ultrasonic Transducers.

    Caliano, Giosue; Matrone, Giulia; Savoia, Alessandro Stuart

    2017-02-01

    Capacitive micromachined ultrasonic transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are microelectromechanical devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies on its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and high-performance devices, including both 1-D or 2-D arrays. Being capacitive transducers, CMUTs require a high bias voltage to be properly operated in pulse-echo imaging applications. The typical bias supply residual ripple of high-quality high-voltage (HV) generators is in the millivolt range, which is comparable with the amplitude of the received echo signals, and it is particularly difficult to minimize. The aim of this paper is to analyze the classical CMUT biasing circuits, highlighting the features of each one, and to propose two novel HV generator architectures optimized for CMUT biasing applications. The first circuit proposed is an ultralow-residual ripple (generator that uses an extremely stable sinusoidal power oscillator topology. The second circuit employs a commercially available integrated step-up converter characterized by a particularly efficient switching topology. The circuit is used to bias the CMUT by charging a buffer capacitor synchronously with the pulsing sequence, thus reducing the impact of the switching noise on the received echo signals. The small area of the circuit (about 1.5 cm 2 ) makes it possible to generate the bias voltage inside the probe, very close to the CMUT, making the proposed solution attractive for portable applications. Measurements and experiments are shown to demonstrate the effectiveness of the new approaches presented.

  3. Capacitive sensor for engine oil deterioration measurement

    Shinde, Harish; Bewoor, Anand

    2018-04-01

    A simple system or mechanism for engine Oil (lubricating oil) deterioration monitoring is a need. As engine oil is an important element in I C engines and it is exposed to various strains depending on the operating conditions. If it becomes contaminated with dirt and metal particles, it can become too thick or thin and loses its protective properties, leads to unwanted friction. In turn, to avoid an engine failure, the oil must be changed before it loses its protective properties, which may be harmful to engine which deteriorates vehicle performance. At the same time, changing the lubricant too early, cause inefficient use of already depleting resources, also unwanted impact on the environment and economic reasons. Hence, it will be always helpful to know the quality of the oil under use. With this objective, the research work had been undertaken to develop a simple capacitance sensor for quantification of the quality of oil under use. One of the investigated parameter to quantify oil degradation is Viscosity (as per standard testing procedure: DIN 51562-1). In this research work, an alternative method proposed which analyzing change in capacitance of oil, to quantify the quality of oil underuse and compared to a conventional standard method. The experimental results reported in this paper shows trend for the same. Engine oil of grade SAE 15W40 used for light-duty vehicle, vans and passenger cars is used for experimentation. Suggested method can form a base for further research to develop a cost-effective method for indicating the time to change in engine oil quality have been presented.

  4. Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

    Ya' akobovitz, A. [Mechanosynthesis Group, Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Mechanical Engineering, Faculty of Engineering Sciences, Ben-Gurion University, Beer-Sheva (Israel); Bedewy, M. [Mechanosynthesis Group, Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hart, A. J. [Mechanosynthesis Group, Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-02-02

    Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices.

  5. Interdigitated electrodes as impedance and capacitance biosensors: A review

    Mazlan, N. S.; Ramli, M. M.; Abdullah, M. M. A. B.; Halin, D. S. C.; Isa, S. S. M.; Talip, L. F. A.; Danial, N. S.; Murad, S. A. Z.

    2017-09-01

    Interdigitated electrodes (IDEs) are made of two individually addressable interdigitated comb-like electrode structures. IDEs are one of the most favored transducers, widely utilized in technological applications especially in the field of biological and chemical sensors due to their inexpensive, ease of fabrication process and high sensitivity. In order to detect and analyze a biochemical molecule or analyte, the impedance and capacitance signal need to be obtained. This paper investigates the working principle and influencer of the impedance and capacitance biosensors. The impedance biosensor depends on the resistance and capacitance while the capacitance biosensor influenced by the dielectric permittivity. However, the geometry and structures of the interdigitated electrodes affect both impedance and capacitance biosensor. The details have been discussed in this paper.

  6. Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

    Ya'akobovitz, A.; Bedewy, M.; Hart, A. J.

    2015-01-01

    Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices

  7. Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

    Ya'akobovitz, A.; Bedewy, M.; Hart, A. J.

    2015-02-01

    Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices.

  8. Conductive MOF electrodes for stable supercapacitors with high areal capacitance.

    Sheberla, Dennis; Bachman, John C; Elias, Joseph S; Sun, Cheng-Jun; Shao-Horn, Yang; Dincă, Mircea

    2017-02-01

    Owing to their high power density and superior cyclability relative to batteries, electrochemical double layer capacitors (EDLCs) have emerged as an important electrical energy storage technology that will play a critical role in the large-scale deployment of intermittent renewable energy sources, smart power grids, and electrical vehicles. Because the capacitance and charge-discharge rates of EDLCs scale with surface area and electrical conductivity, respectively, porous carbons such as activated carbon, carbon nanotubes and crosslinked or holey graphenes are used exclusively as the active electrode materials in EDLCs. One class of materials whose surface area far exceeds that of activated carbons, potentially allowing them to challenge the dominance of carbon electrodes in EDLCs, is metal-organic frameworks (MOFs). The high porosity of MOFs, however, is conventionally coupled to very poor electrical conductivity, which has thus far prevented the use of these materials as active electrodes in EDLCs. Here, we show that Ni 3 (2,3,6,7,10,11-hexaiminotriphenylene) 2 (Ni 3 (HITP) 2 ), a MOF with high electrical conductivity, can serve as the sole electrode material in an EDLC. This is the first example of a supercapacitor made entirely from neat MOFs as active materials, without conductive additives or other binders. The MOF-based device shows an areal capacitance that exceeds those of most carbon-based materials and capacity retention greater than 90% over 10,000 cycles, in line with commercial devices. Given the established structural and compositional tunability of MOFs, these results herald the advent of a new generation of supercapacitors whose active electrode materials can be tuned rationally, at the molecular level.

  9. Conductive MOF electrodes for stable supercapacitors with high areal capacitance

    Sheberla, Dennis; Bachman, John C.; Elias, Joseph S.; Sun, Cheng-Jun; Shao-Horn, Yang; Dincă, Mircea

    2017-02-01

    Owing to their high power density and superior cyclability relative to batteries, electrochemical double layer capacitors (EDLCs) have emerged as an important electrical energy storage technology that will play a critical role in the large-scale deployment of intermittent renewable energy sources, smart power grids, and electrical vehicles. Because the capacitance and charge-discharge rates of EDLCs scale with surface area and electrical conductivity, respectively, porous carbons such as activated carbon, carbon nanotubes and crosslinked or holey graphenes are used exclusively as the active electrode materials in EDLCs. One class of materials whose surface area far exceeds that of activated carbons, potentially allowing them to challenge the dominance of carbon electrodes in EDLCs, is metal-organic frameworks (MOFs). The high porosity of MOFs, however, is conventionally coupled to very poor electrical conductivity, which has thus far prevented the use of these materials as active electrodes in EDLCs. Here, we show that Ni3(2,3,6,7,10,11-hexaiminotriphenylene)2 (Ni3(HITP)2), a MOF with high electrical conductivity, can serve as the sole electrode material in an EDLC. This is the first example of a supercapacitor made entirely from neat MOFs as active materials, without conductive additives or other binders. The MOF-based device shows an areal capacitance that exceeds those of most carbon-based materials and capacity retention greater than 90% over 10,000 cycles, in line with commercial devices. Given the established structural and compositional tunability of MOFs, these results herald the advent of a new generation of supercapacitors whose active electrode materials can be tuned rationally, at the molecular level.

  10. Current source enhancements in Electrical Impedance Spectroscopy (EIS) to cancel unwanted capacitive effects

    Zarafshani, Ali; Bach, Thomas; Chatwin, Chris; Xiang, Liangzhong; Zheng, Bin

    2017-03-01

    Electrical Impedance Spectroscopy (EIS) has emerged as a non-invasive imaging modality to detect and quantify functional or electrical properties related to the suspicious tumors in cancer screening, diagnosis and prognosis assessment. A constraint on EIS systems is that the current excitation system suffers from the effects of stray capacitance having a major impact on the hardware subsystem as the EIS is an ill-posed inverse problem which depends on the noise level in EIS measured data and regularization parameter in the reconstruction algorithm. There is high complexity in the design of stable current sources, with stray capacitance reducing the output impedance and bandwidth of the system. To confront this, we have designed an EIS current source which eliminates the effect of stray capacitance and other impacts of the capacitance via a variable inductance. In this paper, we present a combination of operational CCII based on a generalized impedance converter (OCCII-GIC) with a current source. The aim of this study is to use the EIS system as a biomedical imaging technique, which is effective in the early detection of breast cancer. This article begins with the theoretical description of the EIS structure, current source topologies and proposes a current conveyor in application of a Gyrator to eliminate the current source limitations and its development followed by simulation and experimental results. We demonstrated that the new design could achieve a high output impedance over a 3MHz frequency bandwidth when compared to other types of GIC circuits combined with an improved Howland topology.

  11. Holey nickel-cobalt layered double hydroxide thin sheets with ultrahigh areal capacitance

    Zhi, Lei; Zhang, Wenliang; Dang, Liqin; Sun, Jie; Shi, Feng; Xu, Hua; Liu, Zonghuai; Lei, Zhibin

    2018-05-01

    Strong coupling of electroactive components on conductive carbonaceous matrix to fabricate flexible hybrid electrodes represents a promising approach towards high performance supercapacitors. This work reports the fabrication of holey nickel cobalt layered double hydroxide (NiCo-LDH) nanosheets that are vertically grown on the cotton cloth-derived activated textile carbon (aTC). The abundant nanoholes on the thin-sheet NiCo-LDH not only enhance the electrode efficiency for efficient Faradaic redox reactions but also facilitate access of electrolyte to the electrode surface, thus giving rise to 70% capacitance arising from their outer surface. As a result, the aTC-NiCo hybrid electrode is capable of simultaneously achieving extremely high areal capacitance (6.37 F cm-2), mass capacitance (525 F g-1) and volumetric capacitance (249 F cm-3) at a practical level of mass loading (6.72 mg cm-2). Moreover, a solid-state asymmetric capacitor built with aTC-NiCo as positive electrode and active carbon-coated on aTC as negative electrode can deliver a volumetric energy density of 7.4 mWh cm-3 at a power density of 103 mW cm-3, while preserving a superior power performance, satisfying cycling stability and good mechanical flexibility.

  12. Effects of low temperature periodic annealing on the deep-level defects in 200 keV proton irradiated AlGaAs-GaAs solar cells

    Li, S. S.; Chiu, T. T.; Loo, R. Y.

    1981-01-01

    The GaAs solar cell has shown good potential for space applications. However, degradation in performance occurred when the cells were irradiated by high energy electrons and protons in the space environment. The considered investigation is concerned with the effect of periodic thermal annealing on the deep-level defects induced by the 200 keV protons in the AlGaAs-GaAs solar cells. Protons at a fluence of 10 to the 11th P/sq cm were used in the irradiation cycle, while annealing temperatures of 200 C (for 24 hours), 300 C (six hours), and 400 C (six hours) were employed. The most likely candidate for the E(c) -0.71 eV electron trap observed in the 200 keV proton irradiated samples may be due to GaAs antisite, while the observed E(v) +0.18 eV hole trap has been attributed to the gallium vacancy related defect. The obtained results show that periodic annealing in the considered case does not offer any advantages over the one time annealing process.

  13. FEBEX project: full-scale engineered barriers experiment for a deep geological repository for high level radioactive waste in crystalline host rock. Final report

    Alberdi, J.; Barcala, J. M.; Campos, R.; Cuevas, A. M.; Fernandez, E.

    2000-01-01

    FEBEX has the multiple objective of demonstrating the feasibility of manufacturing, handling and constructing the engineered barriers and of developing codes for the thermo-hydro-mechanical and thermo-hydro-geochemical performance assessment of a deep geological repository for high level radioactive wastes. These objectives require integrated theoretical and experimental development work. The experimental work consists of three parts: an in situ test, a mock-up test and a series of laboratory tests. The experiments is based on the Spanish reference concept for crystalline rock, in which the waste capsules are placed horizontally in drifts surround by high density compacted bentonite blocks. In the two large-scale tests, the thermal effects of the wastes were simulated by means of heaters; hydration was natural in the in situ test and controlled in the mock-up test. The large-scale tests, with their monitoring systems, have been in operation for more than two years. the demonstration has been achieved in the in situ test and there are great expectation that numerical models sufficiently validated for the near-field performance assessment will be achieved. (Author)

  14. Earth system modelling on system-level heterogeneous architectures: EMAC (version 2.42) on the Dynamical Exascale Entry Platform (DEEP)

    Christou, Michalis; Christoudias, Theodoros; Morillo, Julián; Alvarez, Damian; Merx, Hendrik

    2016-09-01

    We examine an alternative approach to heterogeneous cluster-computing in the many-core era for Earth system models, using the European Centre for Medium-Range Weather Forecasts Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model as a pilot application on the Dynamical Exascale Entry Platform (DEEP). A set of autonomous coprocessors interconnected together, called Booster, complements a conventional HPC Cluster and increases its computing performance, offering extra flexibility to expose multiple levels of parallelism and achieve better scalability. The EMAC model atmospheric chemistry code (Module Efficiently Calculating the Chemistry of the Atmosphere (MECCA)) was taskified with an offload mechanism implemented using OmpSs directives. The model was ported to the MareNostrum 3 supercomputer to allow testing with Intel Xeon Phi accelerators on a production-size machine. The changes proposed in this paper are expected to contribute to the eventual adoption of Cluster-Booster division and Many Integrated Core (MIC) accelerated architectures in presently available implementations of Earth system models, towards exploiting the potential of a fully Exascale-capable platform.

  15. Deep ground water microbiology in Swedish granite rock and it's relevance for radio-nuclide migration from a Swedish high level nuclear waste repository

    Pedersen, Karsten

    1989-03-01

    Data on numbers, species and activity of deep ground water microbial populations in Swedish granite rock have been collected. Specific studies are performed on radio-nuclid uptake on bacteria judge to be probable inhabitants in Swedish nuclear waste repositories. An integrated mobile field laboratory was used for water sampling and for the immediate counting and inoculation of the samples from boreholes at levels between 129 and 860 m. A sampler adapted for the collection of undisturbed samples for gas analysis was used to collect samples for bacterial enumerations and enrichments. The sampler can be opened and closed from the surface at the actual sampling depth. The samples can subsequently be brought to the surface without contact with air and with the pressure at the actual sampling depth. The number of bacteria were determined in samples from the gas sampler when this was possible. Else numbers are determined in the water that is pumped up to the field lab. The average total number of bacteria is 3 x 10 5 bacterial ml -1 . The number of bacteria possible to recover with plate count arrays from 0.10 to 21.9%. (author)

  16. Defect States in InP/InGaAs/InP Heterostructures by Current-Voltage Characteristics and Deep Level Transient Spectroscopy.

    Vu, Thi Kim Oanh; Lee, Kyoung Su; Lee, Sang Jun; Kim, Eun Kyu

    2018-09-01

    We studied defect states in In0.53Ga0.47As/InP heterojunctions with interface control by group V atoms during metalorganic chemical vapor (MOCVD) deposition. From deep level transient spectroscopy (DLTS) measurements, two defects with activation energies of 0.28 eV (E1) and 0.15 eV (E2) below the conduction band edge, were observed. The defect density of E1 for In0.53Ga0.47As/InP heterojunctions with an addition of As and P atoms was about 1.5 times higher than that of the heterojunction added P atom only. From the temperature dependence of current- voltage characteristics, the thermal activation energies of In0.53Ga0.47As/InP of heterojunctions were estimated to be 0.27 and 0.25 eV, respectively. It appeared that the reverse light current for In0.53Ga0.47As/InP heterojunction added P atom increased only by illumination of a 940 nm-LED light source. These results imply that only the P addition at the interface can enhance the quality of InGaAs/InP heterojunction.

  17. A model for the analysis of a normal evolution scenarios for a deep geological granite repository for high-level radioactive waste

    Cormenzana Lopez, J.L.; Cunado, M.A.; Lopez, M.T.

    1996-01-01

    The methodology usually used to evaluate the behaviour of deep geological repositories for high-level radioactive wastes comprises three phases: Identification of factors (processes, characteristics and events) that can affect the repository. Generation of scenarios. In general, a normal evolution scenario (Reference Scenario) and various disruptive scenarios (earthquake, human intrusion, etc) are considered. Evaluation of the behaviour of the repository in each scenario. The normal evolution scenario taking into account all factors with a high probability of occurrence is the first to be analysed. The performance assessment of behaviour being carried out by ENRESA for the AGP Granite has led to the identification of 63 of these factors. To analyse repository behaviour in the normal evolution scenario, it is necessary to first of all create an integrated model of the global system. This is a qualitative model including the 63 factors identified. For a global view of a such a complex system, it is very useful to graphically display the relationship between factors in an Influence Diagram. This paper shows the Influence Diagram used in the analysis of the AGP Granite Reference Scenario. (Author)

  18. Social transactions with future generations for the management of high level radioactive waste in deep repositories: Reflections on institutional control and retrievability

    Heriard Dubreuil, G.; Schieber, C.; Schneider, T.; Viala, M.

    1999-01-01

    The management of high level radioactive waste and spent fuel is a key issue and one of the most sensitive aspect of radioactive waste management. Recognising that it is the responsibility of our generation to find a way to isolate the waste, deep geological disposals have been envisaged to provide a definitive solution to the problem, in order to avoid 'undue burden on future generations'. However, even if they are buried, the wastes still exist and human intrusion is still possible as well as releases into the environment in the very far future. At the same time, the ongoing reflections on the ethical aspects of disposals show that it is of great worth that we guarantee future generations the same right of control and responsibility that we ourselves enjoy. This paper presents some reflections on the social transactions associated with the management and design of geological repositories. It is focused on the mission of institutional control in the transmission to future generation of a safety patrimony, composed of the know-how and techniques that permit the human community to 'domesticate' and control the risk. As it appears that the efficiency and the confidence in the control system rely mainly on the capability of implementing corrective actions, some considerations on the role, the consequences and the implementation of retrievability are also presented

  19. FEBEX project: full-scale engineered barriers experiment for a deep geological repository for high level radioactive waste in crystalline host rock

    Alberid, J; Barcala, J M; Campos, R; Cuevas, A M; Fernandez, E [Ciemat. Madrid (Spain)

    2000-07-01

    FEBEX has the multiple objective of demonstrating the feasibility of manufacturing, handling and constructing the engineered barriers and of developing codes for the thermo-hydro-mechanical and thermo-hydro-geochemical performance assessment of a deep geological repository for high level radioactive wastes. These objectives require integrated theoretical and experimental development work. The experimental work consists of three parts: an in situ test, a mock-up test and a series of laboratory tests. The experiments is based on the Spanish reference concept for crystalline rock, in which the waste capsules are placed horizontally in drifts surround by high density compacted bentonite blocks. In the two large-scale tests, the thermal effects of the wastes were simulated by means of heaters; hydration was natural in the in situ test and controlled in the mock-up test. The large-scale tests, with their monitoring systems, have been in operation for more than two years. the demonstration has been achieved in the in situ test and there are great expectation that numerical models sufficiently validated for the near-field performance assessment will be achieved. (Author)

  20. Hydrophilic Conjugated Polymers with Large Bandgaps and Deep-Lying HOMO Levels as an Efficient Cathode Interlayer in Inverted Polymer Solar Cells.

    Kan, Yuanyuan; Zhu, Yongxiang; Liu, Zhulin; Zhang, Lianjie; Chen, Junwu; Cao, Yong

    2015-08-01

    Two hydrophilic conjugated polymers, PmP-NOH and PmP36F-NOH, with polar diethanol-amine on the side chains and main chain structures of poly(meta-phenylene) and poly(meta-phenylene-alt-3,6-fluorene), respectively, are successfully synthesized. The films of PmP-NOH and PmP36F-NOH show absorption edges at 340 and 343 nm, respectively. The calculated optical bandgaps of the two polymers are 3.65 and 3.62 eV, respectively, the largest ones so far reported for hydrophilic conjugated polymers. PmP-NOH and PmP36F-NOH also possess deep-lying highest occupied molecular orbital levels of -6.19 and -6.15 eV, respectively. Inserting PmP-NOH and PmP36F-NOH as a cathode interlayer in inverted polymer solar cells with a PTB7/PC71 BM blend as the active layer, high power conversion efficiencies of 8.58% and 8.33%, respectively, are achieved, demonstrating that the two hydrophilic polymers are excellent interlayers for efficient inverted polymer solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A deep-level transient spectroscopy study of gamma-ray irradiation on the passivation properties of silicon nitride layer on silicon

    Dong, Peng; Yu, Xuegong; Ma, Yao; Xie, Meng; Li, Yun; Huang, Chunlai; Li, Mo; Dai, Gang; Zhang, Jian

    2017-08-01

    Plasma-enhanced chemical vapor deposited silicon nitride (SiNx) films are extensively used as passivation material in the solar cell industry. Such SiNx passivation layers are the most sensitive part to gamma-ray irradiation in solar cells. In this work, deep-level transient spectroscopy has been applied to analyse the influence of gamma-ray irradiation on the passivation properties of SiNx layer on silicon. It is shown that the effective carrier lifetime decreases with the irradiation dose. At the same time, the interface state density is significantly increased after irradiation, and its energy distribution is broadened and shifts deeper with respect to the conduction band edge, which makes the interface states becoming more efficient recombination centers for carriers. Besides, C-V characteristics show a progressive negative shift with increasing dose, indicating the generation of effective positive charges in SiNx films. Such positive charges are beneficial for shielding holes from the n-type silicon substrates, i. e. the field-effect passivation. However, based on the reduced carrier lifetime after irradiation, it can be inferred that the irradiation induced interface defects play a dominant role over the trapped positive charges, and therefore lead to the degradation of passivation properties of SiNx on silicon.

  2. Development trends of combined inductance-capacitance electromechanical energy converters

    Karayan Hamlet

    2018-01-01

    Full Text Available In the article the modern state of completely new direction of electromechanical science such as combined inductive-capacitive electromechanics is considered. The wide spectra of its possible practical applications and prospects for further development are analyzed. A new approach for mathematical description of transients in dualcon jugate dynamic systems is proposed. On the basis of the algorithm differential equations for inductive-capacitive compatible electromechanical energy converters are derived. The generalized Lagrangian theory of combined inductively-capacitive electric machines was developed as a union of generalized Lagrangian models of inductive and capacitive electro-mechanical energy converters developed on the basis of the basic principles of binary-conjugate electrophysics. The author gives equations of electrodynamics and electromechanics of combined inductive-capacitive electric machines in case there are active electrotechnical materials of dual purpose (ferroelectromagnets in the structure of their excitation system. At the same time, the necessary Lagrangian for combined inductive-capacitive forces was built using new technologies of interaction between inductive and capacitive subsystems. The joint solution of these equations completely determines the dynamic behavior and energy characteristics of the generalized model of combined machines of any design and in any modes of interaction of their functional elements

  3. Identification of Hadronically-Decaying W Bosons and Top Quarks Using High-Level Features as Input to Boosted Decision Trees and Deep Neural Networks in ATLAS at $\\sqrt{s}$ = 13 TeV

    The ATLAS collaboration

    2017-01-01

    The application of boosted decision trees and deep neural networks to the identification of hadronically-decaying W bosons and top quarks using high-level jet observables as inputs is investigated using Monte Carlo simulations. In the case of both boosted decision trees and deep neural networks, the use of machine learning techniques is found to improve the background rejection with respect to simple reference single jet substructure and mass taggers. Linear correlations between the resulting classifiers and the substructure variables are also presented.

  4. Identification of Hadronically-Decaying W Boson Top Quarks Using High-Level Features as Input to Boosted Decision Trees and Deep Neural Networks in ATLAS at #sqrt{s} = 13 TeV

    Nitta, Tatsumi; The ATLAS collaboration

    2017-01-01

    The application of boosted decision trees and deep neural networks to the identification of hadronically-decaying W bosons and top quarks using high-level jet observables as inputs is investigated using Monte Carlo simulations. In the case of both boosted decision trees and deep neural networks, the use of machine learning techniques is found to improve the background rejection with respect to simple reference single jet substructure and mass taggers. Linear correlations between the resulting classifiers and the substructure variables are also presented.

  5. High Voltage Bi-directional Flyback Converter for Capacitive Actuator

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    in the converter, including the most dominating parameters of the high voltage transformer viz., self-capacitance and leakage inductance. The specific capacitive load for this converter is a dielectric electro active polymer (DEAP) actuator, which can be used as an effective replacement for conventional actuators...... in a number of applications. In this paper, the discharging energy efficiency definition is introduced. The proposed converter has been experimentally tested with the film capacitive load and the DEAP actuator, and the experimental results are shown together with the efficiency measurements....

  6. Human body capacitance: static or dynamic concept? [ESD

    Jonassen, Niels M

    1998-01-01

    A standing human body insulated from ground by footwear and/or floor covering is in principle an insulated conductor and has, as such, a capacitance, i.e. the ability to store a charge and possibly discharge the stored energy in a spark discharge. In the human body, the human body capacitance (HBC...... when a substantial part of the flux extends itself through badly defined stray fields. Since the concept of human body capacitance is normally used in a static (electric) context, it is suggested that the HBC be determined by a static method. No theoretical explanation of the observed differences...

  7. Design and Optimization of Capacitated Supply Chain Networks Including Quality Measures

    Krystel K. Castillo-Villar

    2014-01-01

    Full Text Available This paper presents (1 a novel capacitated model for supply chain network design which considers manufacturing, distribution, and quality costs (named SCND-COQ model and (2 five combinatorial optimization methods, based on nonlinear optimization, heuristic, and metaheuristic approaches, which are used to solve realistic instances of practical size. The SCND-COQ model is a mixed-integer nonlinear problem which can be used at a strategic planning level to design a supply chain network that maximizes the total profit subject to meeting an overall quality level of the final product at minimum costs. The SCND-COQ model computes the quality-related costs for the whole supply chain network considering the interdependencies among business entities. The effectiveness of the proposed solution approaches is shown using numerical experiments. These methods allow solving more realistic (capacitated supply chain network design problems including quality-related costs (inspections, rework, opportunity costs, and others within a reasonable computational time.

  8. A Review on the Recent Development of Capacitive Wireless Power Transfer Technology

    Fei Lu

    2017-11-01

    Full Text Available Capacitive power transfer (CPT technology is an effective and important alternative to the conventional inductive power transfer (IPT. It utilizes high-frequency electric fields to transfer electric power, which has three distinguishing advantages: negligible eddy-current loss, relatively low cost and weight, and excellent misalignment performance. In recent years, the power level and efficiency of CPT systems has been significantly improved and has reached the power level suitable for electric vehicle charging applications. This paper reviews the latest developments in CPT technology, focusing on two key technologies: the compensation circuit topology and the capacitive coupler structure. The comparison with the IPT system and some critical issues in practical applications are also discussed. Based on these analyses, the future research direction can be developed and the applications of the CPT technology can be promoted.

  9. Field tests of electric survey using capacitive electrodes; Kyapashita denkyoku wo mochiita denki tansarei

    Miyazaki, I; Iseki, S; Kobayashi, T [OYO Corp., Tokyo (Japan)

    1997-10-22

    This paper describes field test results of electric survey using capacitive electrodes. When two metal plates are approached without contacting with the ground and voltage is applied between the plates, current flows in the ground. The metal plates and the ground work as a capacitor. Charges are stored between them. These metal plates having insulation with the ground are called capacitive electrodes. When ac voltage is applied between a pair of capacitors, current flows continuously in the ground without saturating the capacitors. Resistivity of the ground can be determined by measuring the level of current flowing in the ground and the level of potential. As a result of the field tests, it was found that the present method is superior to the conventional method in around ten times. However, to obtain high quality data, water spraying, reduced towing speed at the low resistivity ground such as clay and soil, and grass mowing are required. 3 refs., 5 figs., 1 tab.

  10. Attofarad resolution capacitance-voltage measurement of nanometer scale field effect transistors utilizing ambient noise

    Gokirmak, Ali; Inaltekin, Hazer; Tiwari, Sandip

    2009-01-01

    A high resolution capacitance-voltage (C-V) characterization technique, enabling direct measurement of electronic properties at the nanoscale in devices such as nanowire field effect transistors (FETs) through the use of random fluctuations, is described. The minimum noise level required for achieving sub-aF (10 -18 F) resolution, the leveraging of stochastic resonance, and the effect of higher levels of noise are illustrated through simulations. The non-linear ΔC gate-source/drain -V gate response of FETs is utilized to determine the inversion layer capacitance (C inv ) and carrier mobility. The technique is demonstrated by extracting the carrier concentration and effective electron mobility in a nanoscale Si FET with C inv = 60 aF.

  11. Design Considerations in Capacitively Coupled Plasmas

    Song, Sang-Heon; Ventzek, Peter; Ranjan, Alok

    2015-11-01

    Microelectronics industry has driven transistor feature size scaling from 10-6 m to 10-9 m during the past 50 years, which is often referred to as Moore's law. It cannot be overstated that today's information technology would not have been so successful without plasma material processing. One of the major plasma sources for the microelectronics fabrication is capacitively coupled plasmas (CCPs). The CCP reactor has been intensively studied and developed for the deposition and etching of different films on the silicon wafer. As the feature size gets to around 10 nm, the requirement for the process uniformity is less than 1-2 nm across the wafer (300 mm). In order to achieve the desired uniformity, the hardware design should be as precise as possible before the fine tuning of process condition is applied to make it even better. In doing this procedure, the computer simulation can save a significant amount of resources such as time and money which are critical in the semiconductor business. In this presentation, we compare plasma properties using a 2-dimensional plasma hydrodynamics model for different kinds of design factors that can affect the plasma uniformity. The parameters studied in this presentation include chamber accessing port, pumping port, focus ring around wafer substrate, and the geometry of electrodes of CCP.

  12. Hydrogen atom kinetics in capacitively coupled plasmas

    Nunomura, Shota; Katayama, Hirotaka; Yoshida, Isao

    2017-05-01

    Hydrogen (H) atom kinetics has been investigated in capacitively coupled very high frequency (VHF) discharges at powers of 16-780 mW cm-2 and H2 gas pressures of 0.1-2 Torr. The H atom density has been measured using vacuum ultra violet absorption spectroscopy (VUVAS) with a micro-discharge hollow cathode lamp as a VUV light source. The measurements have been performed in two different electrode configurations of discharges: conventional parallel-plate diode and triode with an intermediate mesh electrode. We find that in the triode configuration, the H atom density is strongly reduced across the mesh electrode. The H atom density varies from ˜1012 cm-3 to ˜1010 cm-3 by crossing the mesh with 0.2 mm in thickness and 36% in aperture ratio. The fluid model simulations for VHF discharge plasmas have been performed to study the H atom generation, diffusion and recombination kinetics. The simulations suggest that H atoms are generated in the bulk plasma, by the electron impact dissociation (e + H2 \\to e + 2H) and the ion-molecule reaction (H2 + + H2 \\to {{{H}}}3+ + H). The diffusion of H atoms is strongly limited by a mesh electrode, and thus the mesh geometry influences the spatial distribution of the H atoms. The loss of H atoms is dominated by the surface recombination.

  13. Locating Depots for Capacitated Vehicle Routing

    Gørtz, Inge Li; Nagarajan, Viswanath

    2011-01-01

    that all demands are satisfied and the total cost is minimized. Our main result is a constant-factor approximation algorithm for k-LocVRP. To achieve this result, we reduce k-LocVRP to the following generalization of k median, which might be of independent interest. Given a metric (V, d), bound k...... median forest, which leads to a (12+E)-approximation algorithm for k-LocVRP, for any constant E > 0. The algorithm for k median forest is t-swap local search, and we prove that it has locality gap 3 + 2 t ; this generalizes the corresponding result for k median [3]. Finally we consider the k median......We study a location-routing problem in the context of capacitated vehicle routing. The input to k-LocVRP is a set of demand locations in a metric space and a fleet of k vehicles each of capacity Q. The objective is to locate k depots, one for each vehicle, and compute routes for the vehicles so...

  14. Ultrasensitive interdigitated capacitance immunosensor using gold nanoparticles

    Alizadeh Zeinabad, Hojjat; Ghourchian, Hedayatollah; Falahati, Mojtaba; Fathipour, Morteza; Azizi, Marzieh; Boutorabi, Seyed Mehdi

    2018-06-01

    Immunosensors based on interdigitated electrodes (IDEs), have recently demonstrated significant improvements in the sensitivity of capacitance detection. Herein, a novel type of highly sensitive, compact and portable immunosensor based on a gold interdigital capacitor has been designed and developed for the rapid detection of hepatitis B surface antigen (HBsAg). To improve the efficiency of antibody immobilization and time-saving, a self-assembled monolayer (SAM) of 2-mercaptoethylamine film was coated on IDEs. Afterwards, carboxyl groups on primary antibodies were activated through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and were immobilized on amino-terminated SAM for better control of the oriented immobilization of antibodies on gold IDEs. In addition, gold nanoparticles conjugated with a secondary antibody were used to enhance the sensitivity. Under optimal conditions, the immunosensor exhibited the sensitivity of 0.22 nF.pg ml–1, the linear range from 5 pg ml‑1 to 1 ng ml–1 and the detection limit of 1.34 pg ml‑1, at a signal-to-noise ratio of 3.

  15. Seismic risk mitigation in deep level South African mines by state of the art underground monitoring - Joint South African and Japanese study

    Milev, A.; Durrheim, R.; Nakatani, M.; Yabe, Y.; Ogasawara, H.; Naoi, M.

    2012-04-01

    Two underground sites in a deep level gold mine in South Africa were instrumented by the Council for Scientific and Industrial Research (CSIR) with tilt meters and seismic monitors. One of the sites was also instrumented by JApanese-German Underground Acoustic emission Research in South Africa (JAGUARS) with a small network, approximately 40m span, of eight Acoustic Emission (AE) sensors. The rate of tilt, defined as quasi-static deformations, and the seismic ground motion, defined as dynamic deformations, were analysed in order to understand the rock mass behavior around deep level mining. In addition the high frequency AE events recorded at hypocentral distances of about 50m located at 3300m below the surface were analysed. A good correspondence between the dynamic and quasi-static deformations was found. The rate of coseismic and aseismic tilt, as well as seismicity recorded by the mine seismic network, are approximately constant until the daily blasting time, which takes place from about 19:30 until shortly before 21:00. During the blasting time and the subsequent seismic events the coseismic and aseismic tilt shows a rapid increase.Much of the quasi-static deformation, however, occurs independently of the seismic events and was described as 'slow' or aseismic events. During the monitoring period a seismic event with MW 2.2 occurred in the vicinity of the instrumented site. This event was recorded by both the CSIR integrated monitoring system and JAGUARS acoustic emotion network. The tilt changes associated with this event showed a well pronounced after-tilt. The aftershock activities were also well recorded by the acoustic emission and the mine seismic networks. More than 21,000 AE aftershocks were located in the first 150 hours after the main event. Using the distribution of the AE events the position of the fault in the source area was successfully delineated. The distribution of the AE events following the main shock was related to after tilt in order to

  16. Floristic composition of gold and uranium tailings dams, and adja­cent polluted areas, on South Africa’s deep-level mines

    I. M. Weiersbye

    2006-08-01

    Full Text Available Gold and uranium tailings (‘slimes’ dams and the adjacent polluted soils in the deep-level mining regions of South Africa (Carletonville, Klerksdorp and Welkom were surveyed for the frequency of occurrence of naturally colonizing, actively introduced and persisting plant species. Fifty-six tailings dams with a combined area of 5864 ha. and a similar area o f tail- ings-polluted soils, were surveyed between July 1996 and March 1997. During the survey, 376 plant species and subspecies were recorded from the dams and adjacent polluted soils, with an additional  8 6  records obtained between 1998 and 2003 (i.e. a total of 462 taxa: species and infraspecific species. Overall, the most commonly represented families were the Poaceae (107 species and subspecies, Asteraceae (81. Fabaceae (55 and Anacardiaceae (16. with other families represented by just one to 14 species. Only 60 species were common to all three regions, and of these 24 had been introduced during rehabilitation attempts. Most of the species found on tailings were persisters or natural colonizers (53-88%, depending on substrate, with the vast majority being indigenous and perennial taxa (76% and 85% respectively, with semi-woody to woody growth forms (6 6% being resprouters, forbs, shrubs and trees. Less than 4% of the naturally-colonizing taxa found during the survey had also been introduced by vegetation practitioners. The majority of introduced plants were alien herbaceous taxa. The number and frequency of annuals was only high on recently vegetated sites, whereas annuals were rarely present on old-vegetated and never-vegetated dams. This list includes a wide range of indigenous plant species that may be suitable for phytoremediation of tailings dams and polluted soils due to their apparent tolerance of acid mine drainage and salinity.

  17. A preliminary study on the long-term geologic stability for deep geological disposal of high level radioactive waste in Korea

    Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Park, Byoung Yoon; Koh, Young Kown [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-03-01

    Geology of the Korean peninsula could be grouped by 7 rock types such as plutonic rocks, crystalline gneisses, metasedimentary rocks, Paleozoic and Mesozoic sedimentary rocks, porous and massive volcanic rocks. The plutonic rock type is the largest rock groups occupying about 35.2% over the peninsula. Tectonic movement could be classified as four great stages as Precambrian, Songnim, Daebo and Bulkuksa even though the ambiguous of prior Songnim. It would be supposed to deep relationship between tectonic movement, orogeny and magmatism. And also, the magmatism within the peninsula could be divided into 5 stages such as 1st stage of Precambrian(>570Ma), 2nd stage of late Paleozoic(>250Ma), 3rd stage of early to mid Mesozoic(200-300Ma), 4th stage of late Mesozoic(135-60Ma) and 5th stage of post early Tertiary(50Ma>). In the seismicities, the peninsula has some characteristics that of the intra-plate seismic characteristics located at south eastern part of the Eurasian plate apart from the boundary of the Pacific and Philippine plate. Eurasian plate is under the two stress direction acting eastward stresses induced the collision of Indo- Australlian plate and westward stresses due to the subduction of due the Pacific and Philippine plate. For the purpose of the quantitative analysis for the safety assessment of HLW disposal, it would be desired to have the long range approach concept for the characterization of FEPs such as upper stated including climate, sae level change, uplift and subsidence, erosion and sedimentation. 38 refs., 18 figs., 25 tabs. (Author)

  18. Clay 2001 dossier: progress report on feasibility studies and research into deep geological disposal of high-level, long-lived waste

    2001-12-01

    A French Act of Parliament passed on 30 December 1991 set out the main areas of research required to prepare solutions for the long-term management of high-level, long-lived radioactive waste. The three avenues of research listed in the Act included a feasibility study of the deep geological disposal of these waste, with responsibility for steering the study given to ANDRA, France National Agency for Radioactive Waste Management. Following government decisions taken in 1998, the study focused on two types of geological medium, clay and granite. The clay formations study is essentially based on results from an underground laboratory sited at the border between the Meuse and Haute-Marne departments, where the Callovo-Oxfordian argillite beds are being investigated. No site has yet been chosen for an underground laboratory for the granite study, so for the time being this will draw on generic work and on research carried out in laboratories outside France. ANDRA has decided to present an initial report on the results of its research programme, publishing a dossier on the work on clay formations in 2001 with a second dossier covering the work on granite due for release in 2002. This dossier is thus a review of the work carried out by ANDRA on the feasibility study into a radioactive waste repository in a clay formation. It represents one step in a process of studies and research work leading up to the submission of a report due in 2005 containing ANDRA conclusions on the feasibility of a repository in the clay formation. (author)

  19. Assessment of azadirachtin-A, a neem tetranortritarpinoid, on rat spermatozoa during in vitro capacitation.

    Katte, Teesta V; Rajyalakshmi, Malempati; Aladakatti, Ravindranath H

    2018-05-05

    The exploration of the biological assessment of technical azadirachtin, a tetranortritarpinoid from the neem seed kernel, was reviewed. The present study was, therefore, designed to evaluate the dose-dependent in vitro effects of azadirachtin-A, particularly on the functional studies and determination of molecular events, which are critical in the process of sperm capacitation. To assess the effects of the azadirachtin-A on the functional studies, sperm capacitation, the total sperm adenosine triphosphate levels, acrosome reaction (AR), the sperm-egg interaction and the determination of molecular events like cyclic adenosine-3',5'-monophosphate and calcium levels, the appropriate volumes of the sperm suspension were added to the medium to a final concentration of 1×106 sperm/mL and incubated in a humidified atmosphere of 5% CO2 in air at 37°C. The increasing quantities 0.5-2.0 mM/mL and the equivalent volumes of 50% dimethyl sulfoxide were added to the control dishes prior to the addition of spermatozoa and then observed at various time-points for motility and other analyses. Results revealed the dose- and time-dependent decrease in the functional consequence of capacitation, i.e. the percentage of motile spermatozoa, motility score and sperm motility index, levels of molecular events in spermatozoa, followed by declined spontaneous AR leading to lesser binding of the cauda epididymal sperm to the Zona pellucida. The findings confirm the inhibition of rat sperm motility by blocking some biochemical pathways like energy utilization. They also demonstrate that sperm capacitation is associated with the decrease in AR and that the levels of molecular events in spermatozoa can guide us towards the development of a new male contraceptive constituent.

  20. A capacitive ECG array with visual patient feedback.

    Eilebrecht, Benjamin; Schommartz, Antje; Walter, Marian; Wartzek, Tobias; Czaplik, Michael; Leonhardt, Steffen

    2010-01-01

    Capacitive electrocardiogram (ECG) sensing is a promising technique for less constraining vital signal measurement and close to a commercial application. Even bigger trials testing the diagnostic significance were already done with single lead systems. Anyway, most applications to be found in research are limited to one channel and thus limited in its diagnostic relevance as only diseases coming along with a change of the heart rate can be diagnosed adequately. As a consequence the need for capacitive multi-channel ECGs combining the diagnostic relevance and the advantages of capacitive ECG sensing emerges. This paper introduces a capacitive ECG measurement system which allows the recording of standardized ECG leads according to Einthoven and Goldberger by means of an electrode array with nine electrodes.