WorldWideScience

Sample records for volumetric charge density

  1. Superficial Collagen Fibril Modulus and Pericellular Fixed Charge Density Modulate Chondrocyte Volumetric Behaviour in Early Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Petri Tanska

    2013-01-01

    Full Text Available The aim of this study was to investigate if the experimentally detected altered chondrocyte volumetric behavior in early osteoarthritis can be explained by changes in the extracellular and pericellular matrix properties of cartilage. Based on our own experimental tests and the literature, the structural and mechanical parameters for normal and osteoarthritic cartilage were implemented into a multiscale fibril-reinforced poroelastic swelling model. Model simulations were compared with experimentally observed cell volume changes in mechanically loaded cartilage, obtained from anterior cruciate ligament transected rabbit knees. We found that the cell volume increased by 7% in the osteoarthritic cartilage model following mechanical loading of the tissue. In contrast, the cell volume decreased by 4% in normal cartilage model. These findings were consistent with the experimental results. Increased local transversal tissue strain due to the reduced collagen fibril stiffness accompanied with the reduced fixed charge density of the pericellular matrix could increase the cell volume up to 12%. These findings suggest that the increase in the cell volume in mechanically loaded osteoarthritic cartilage is primarily explained by the reduction in the pericellular fixed charge density, while the superficial collagen fibril stiffness is suggested to contribute secondarily to the cell volume behavior.

  2. Holographic charge density waves

    CERN Document Server

    Donos, Aristomenis

    2013-01-01

    We show that strongly coupled holographic matter at finite charge density can exhibit charge density wave phases which spontaneously break translation invariance while preserving time-reversal and parity invariance. We show that such phases are possible within Einstein-Maxwell-dilaton theory in general spacetime dimensions. We also discuss related spatially modulated phases when there is an additional coupling to a second vector field, possibly with non-zero mass. We discuss how these constructions, and others, should be associated with novel spatially modulated ground states.

  3. Holographic charge density waves

    Science.gov (United States)

    Donos, Aristomenis; Gauntlett, Jerome P.

    2013-06-01

    We show that strongly coupled holographic matter at finite charge density can exhibit charge density wave phases which spontaneously break translation invariance while preserving time-reversal and parity invariance. We show that such phases are possible within Einstein-Maxwell-dilaton theory in general spacetime dimensions. We also discuss related spatially modulated phases when there is an additional coupling to a second vector field, possibly with nonzero mass. We discuss how these constructions, and others, should be associated with novel spatially modulated ground states.

  4. Mammographic density estimation with automated volumetric breast density measurement.

    Science.gov (United States)

    Ko, Su Yeon; Kim, Eun-Kyung; Kim, Min Jung; Moon, Hee Jung

    2014-01-01

    To compare automated volumetric breast density measurement (VBDM) with radiologists' evaluations based on the Breast Imaging Reporting and Data System (BI-RADS), and to identify the factors associated with technical failure of VBDM. In this study, 1129 women aged 19-82 years who underwent mammography from December 2011 to January 2012 were included. Breast density evaluations by radiologists based on BI-RADS and by VBDM (Volpara Version 1.5.1) were compared. The agreement in interpreting breast density between radiologists and VBDM was determined based on four density grades (D1, D2, D3, and D4) and a binary classification of fatty (D1-2) vs. dense (D3-4) breast using kappa statistics. The association between technical failure of VBDM and patient age, total breast volume, fibroglandular tissue volume, history of partial mastectomy, the frequency of mass > 3 cm, and breast density was analyzed. The agreement between breast density evaluations by radiologists and VBDM was fair (k value = 0.26) when the four density grades (D1/D2/D3/D4) were used and moderate (k value = 0.47) for the binary classification (D1-2/D3-4). Twenty-seven women (2.4%) showed failure of VBDM. Small total breast volume, history of partial mastectomy, and high breast density were significantly associated with technical failure of VBDM (p = 0.001 to 0.015). There is fair or moderate agreement in breast density evaluation between radiologists and VBDM. Technical failure of VBDM may be related to small total breast volume, a history of partial mastectomy, and high breast density.

  5. Volumetric breast density affects performance of digital screening mammography.

    Science.gov (United States)

    Wanders, Johanna O P; Holland, Katharina; Veldhuis, Wouter B; Mann, Ritse M; Pijnappel, Ruud M; Peeters, Petra H M; van Gils, Carla H; Karssemeijer, Nico

    2017-02-01

    To determine to what extent automatically measured volumetric mammographic density influences screening performance when using digital mammography (DM). We collected a consecutive series of 111,898 DM examinations (2003-2011) from one screening unit of the Dutch biennial screening program (age 50-75 years). Volumetric mammographic density was automatically assessed using Volpara. We determined screening performance measures for four density categories comparable to the American College of Radiology (ACR) breast density categories. Of all the examinations, 21.6% were categorized as density category 1 ('almost entirely fatty') and 41.5, 28.9, and 8.0% as category 2-4 ('extremely dense'), respectively. We identified 667 screen-detected and 234 interval cancers. Interval cancer rates were 0.7, 1.9, 2.9, and 4.4‰ and false positive rates were 11.2, 15.1, 18.2, and 23.8‰ for categories 1-4, respectively (both p-trend density categories: 85.7, 77.6, 69.5, and 61.0% for categories 1-4, respectively (p-trend density, automatically measured on digital mammograms, impacts screening performance measures along the same patterns as established with ACR breast density categories. Since measuring breast density fully automatically has much higher reproducibility than visual assessment, this automatic method could help with implementing density-based supplemental screening.

  6. Estimation of volumetric breast density for breast cancer risk prediction

    Science.gov (United States)

    Pawluczyk, Olga; Yaffe, Martin J.; Boyd, Norman F.; Jong, Roberta A.

    2000-04-01

    Mammographic density (MD) has been shown to be a strong risk predictor for breast cancer. Compared to subjective assessment by a radiologist, computer-aided analysis of digitized mammograms provides a quantitative and more reproducible method for assessing breast density. However, the current methods of estimating breast density based on the area of bright signal in a mammogram do not reflect the true, volumetric quantity of dense tissue in the breast. A computerized method to estimate the amount of radiographically dense tissue in the overall volume of the breast has been developed to provide an automatic, user-independent tool for breast cancer risk assessment. The procedure for volumetric density estimation consists of first correcting the image for inhomogeneity, then performing a volume density calculation. First, optical sensitometry is used to convert all images to the logarithm of relative exposure (LRE), in order to simplify the image correction operations. The field non-uniformity correction, which takes into account heel effect, inverse square law, path obliquity and intrinsic field and grid non- uniformity is obtained by imaging a spherical section PMMA phantom. The processed LRE image of the phantom is then used as a correction offset for actual mammograms. From information about the thickness and placement of the breast, as well as the parameters of a breast-like calibration step wedge placed in the mammogram, MD of the breast is calculated. Post processing and a simple calibration phantom enable user- independent, reliable and repeatable volumetric estimation of density in breast-equivalent phantoms. Initial results obtained on known density phantoms show the estimation to vary less than 5% in MD from the actual value. This can be compared to estimated mammographic density differences of 30% between the true and non-corrected values. Since a more simplistic breast density measurement based on the projected area has been shown to be a strong indicator

  7. Charge density waves in solids

    CERN Document Server

    Gor'kov, LP

    2012-01-01

    The latest addition to this series covers a field which is commonly referred to as charge density wave dynamics.The most thoroughly investigated materials are inorganic linear chain compounds with highly anisotropic electronic properties. The volume opens with an examination of their structural properties and the essential features which allow charge density waves to develop.The behaviour of the charge density waves, where interesting phenomena are observed, is treated both from a theoretical and an experimental standpoint. The role of impurities in statics and dynamics is considered and an

  8. Microscopic Charge Density Wave Transport

    NARCIS (Netherlands)

    Slot, Erwin

    2005-01-01

    This thesis describes the work performed on crystals with a phase transition to a Charge-Density Wave (CDW). The electrical transport properties change when crystal sizes are smaller than characteristic length scales for CDWs, typically 1 micrometer. In contrast to metals, semiconductors and superco

  9. High Volumetric Energy Density Hybrid Supercapacitors Based on Reduced Graphene Oxide Scrolls.

    Science.gov (United States)

    Rani, Janardhanan R; Thangavel, Ranjith; Oh, Se-I; Woo, Jeong Min; Chandra Das, Nayan; Kim, So-Yeon; Lee, Yun-Sung; Jang, Jae-Hyung

    2017-07-12

    The low volumetric energy density of reduced graphene oxide (rGO)-based electrodes limits its application in commercial electrochemical energy storage devices that require high-performance energy storage capacities in small volumes. The volumetric energy density of rGO-based electrode materials is very low due to their low packing density. A supercapacitor with enhanced packing density and high volumetric energy density is fabricated using doped rGO scrolls (GFNSs) as the electrode material. The restacking of rGO sheets is successfully controlled through synthesizing the doped scroll structures while increasing the packing density. The fabricated cell exhibits an ultrahigh volumetric energy density of 49.66 Wh/L with excellent cycling stability (>10 000 cycles). This unique design strategy for the electrode material has significant potential for the future supercapacitors with high volumetric energy densities.

  10. Optimization of volumetric breast density estimation in digital mammograms.

    Science.gov (United States)

    Holland, Katharina; Gubern-Mérida, Albert; Mann, Ritse M; Karssemeijer, Nico

    2017-05-07

    Fibroglandular tissue volume and percent density can be estimated in unprocessed mammograms using a physics-based method, which relies on an internal reference value representing the projection of fat only. However, pixels representing fat only may not be present in dense breasts, causing an underestimation of density measurements. In this work, we investigate alternative approaches for obtaining a tissue reference value to improve density estimations, particularly in dense breasts. Two of three investigated reference values (F1, F2) are percentiles of the pixel value distribution in the breast interior (the contact area of breast and compression paddle). F1 is determined in a small breast interior, which minimizes the risk that peripheral pixels are included in the measurement at the cost of increasing the chance that no proper reference can be found. F2 is obtained using a larger breast interior. The new approach which is developed for very dense breasts does not require the presence of a fatty tissue region. As reference region we select the densest region in the mammogram and assume that this represents a projection of entirely dense tissue embedded between the subcutaneous fatty tissue layers. By measuring the thickness of the fat layers a reference (F3) can be computed. To obtain accurate breast density estimates irrespective of breast composition we investigated a combination of the results of the three reference values. We collected 202 pairs of MRI's and digital mammograms from 119 women. We compared the percent dense volume estimates based on both modalities and calculated Pearson's correlation coefficients. With the references F1-F3 we found respectively a correlation of [Formula: see text], [Formula: see text] and [Formula: see text]. Best results were obtained with the combination of the density estimations ([Formula: see text]). Results show that better volumetric density estimates can be obtained with the hybrid method, in particular for dense

  11. Mammographic density measurement: a comparison of automated volumetric density measurement to BIRADS

    Science.gov (United States)

    McEntee, Mark F.; Damases, Christine N.

    2014-03-01

    The aim of this study is to compare mammographic breast density assessment with automated volumetric software with Breast Imaging Reporting and Data System (BIRADS) categorization by radiologists on two imaging systems. A data set of 120 mammograms was classified by twenty American Board of Radiology (ABR) Examiners. The mammograms were of 20 women (mean age, 60 years; range, 42-89 years). These women were image twice once with GE system and the following year with Hologic system. These images also had their volumetric density classified by using Volpara Density Grade (VDG). The radiologists were asked to estimate the mammographic density according to BIRADS categories (1- 4). There was a moderate agreement between VDG classification and radiologist BIRADS density shown with Cohen's Kappa (K=0.45; pBIRADS having a mean of 2.13 and the mean VDG higher at 2.50 (t = -11.99; pBIRADS showed a positive strong correlation (r=0.84; pBIRADS and VDG AvBD% also showed a strong positive correlation (r=0.86; pBIRADS categories for each of the VDG AvBD% classifications. Using Volpara, the Hologic system showed a higher meanAvBD% (10.02 vs. 9.97). However using BIRADS the Hologic systems showed a lower mean (2.05 vs. 2.21). Automated systems demonstrated higher internal validity. The results demonstrated a moderate agreement and a strong correlation between VDG classification and radiologist BIRADS density assessment.

  12. Using Volumetric Breast Density to Quantify the Potential Masking Risk of Mammographic Density.

    Science.gov (United States)

    Destounis, Stamatia; Johnston, Lisa; Highnam, Ralph; Arieno, Andrea; Morgan, Renee; Chan, Ariane

    2017-01-01

    The purposes of this study were to compare BI-RADS density categories with quantitative volumetric breast density (VBD) for the reporting of mammographic sensitivity and to identify which patient factors are most predictive of a diagnosis of interval cancer of the breast versus screen-detected cancer. This retrospective study included screen-detected cancers (n = 652) and interval cancers (n = 119) identified between January 2009 and December 2012. Multivariate logistic regression analysis was used to determine which patient factors are predictive of a diagnosis of interval cancer. Sensitivity (screen-detected cancer / [screen-detected cancer + interval cancer]) was determined with the BI-RADS 4th edition density categories and an automated equivalent density grade obtained with a proprietary tool. Sensitivity changes within automated density grade categories were investigated by use of quantitative thresholds at the midpoints of each category. In univariate analysis, age, menopausal status, and breast density were associated with a diagnosis of interval cancer. Of these risk factors, breast density was the only independent factor whether it was assessed by visual BI-RADS category (odds ratio, 3.54; 95% CI, 1.55-8.10), automated density grade (odds ratio, 4.68; 95% CI, 2.26-9.67), or VBD (odds ratio, 4.51; 95% CI, 1.92-10.61). Sensitivity decreased consistently across increasing automated density grade categories from fatty to extremely dense (95%, 89%, 83%, 65%) and less so for visual BI-RADS (82%, 90%, 84%, 66%). Further dichotomization with VBD cutoffs showed a striking linear relation between VBD and sensitivity (R(2) = 0.959). In this study, breast density was the only risk factor significantly associated with a diagnosis of interval cancer versus screen-detected cancer. Quantitative VBD captures the potential masking risk of breast density more precisely than does the widely used visual BI-RADS density classification system.

  13. Quantum crystallographic charge density of urea

    OpenAIRE

    Wall, Michael E.

    2015-01-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crys...

  14. Effect of compression paddle tilt correction on volumetric breast density estimation.

    Science.gov (United States)

    Kallenberg, Michiel G J; van Gils, Carla H; Lokate, Mariëtte; den Heeten, Gerard J; Karssemeijer, Nico

    2012-08-21

    For the acquisition of a mammogram, a breast is compressed between a compression paddle and a support table. When compression is applied with a flexible compression paddle, the upper plate may be tilted, which results in variation in breast thickness from the chest wall to the breast margin. Paddle tilt has been recognized as a major problem in volumetric breast density estimation methods. In previous work, we developed a fully automatic method to correct the image for the effect of compression paddle tilt. In this study, we investigated in three experiments the effect of paddle tilt and its correction on volumetric breast density estimation. Results showed that paddle tilt considerably affected accuracy of volumetric breast density estimation, but that effect could be reduced by tilt correction. By applying tilt correction, a significant increase in correspondence between mammographic density estimates and measurements on MRI was established. We argue that in volumetric breast density estimation, tilt correction is both feasible and essential when mammographic images are acquired with a flexible compression paddle.

  15. Optimization of volumetric breast density estimation in digital mammograms

    NARCIS (Netherlands)

    Holland, K.; Gubern Merida, A.; Mann, R.M.; Karssemeijer, N.

    2017-01-01

    Fibroglandular tissue volume and percent density can be estimated in unprocessed mammograms using a physics-based method, which relies on an internal reference value representing the projection of fat only. However, pixels representing fat only may not be present in dense breasts, causing an

  16. Study of Volumetrically Heated Ultra-High Energy Density Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rocca, Jorge J. [Colorado State Univ., Fort Collins, CO (United States)

    2016-10-27

    Heating dense matter to millions of degrees is important for applications, but requires complex and expensive methods. The major goal of the project was to demonstrate using a compact laser the creation of a new ultra-high energy density plasma regime characterized by simultaneous extremely high temperature and high density, and to study it combining experimental measurements and advanced simulations. We have demonstrated that trapping of intense femtosecond laser pulses deep within ordered nanowire arrays can heat near solid density matter into a new ultra hot plasma regime. Extreme electron densities, and temperatures of several tens of million degrees were achieved using laser pulses of only 0.5 J energy from a compact laser. Our x-ray spectra and simulations showed that extremely highly ionized plasma volumes several micrometers in depth are generated by irradiation of gold and Nickel nanowire arrays with femtosecond laser pulses of relativistic intensities. We obtained extraordinarily high degrees of ionization (e.g. we peeled 52 electrons from gold atoms, and up to 26 electrons from nickel atoms). In the process we generated Gigabar pressures only exceeded in the central hot spot of highly compressed thermonuclear fusion plasmas.. The plasma created after the dissolved wires expand, collide, and thermalize, is computed to have a thermal energy density of 0.3 GJ cm-3 and a pressure of 1-2 Gigabar. These are pressures only exceeded in highly compressed thermonuclear fusion plasmas. Scaling these results to higher laser intensities promises to create plasmas with temperatures and pressures exceeding those in the center of the sun.

  17. Bonding charge density from atomic perturbations.

    Science.gov (United States)

    Wang, Yi; Wang, William Yi; Chen, Long-Qing; Liu, Zi-Kui

    2015-05-15

    Charge transfer among individual atoms is the key concept in modern electronic theory of chemical bonding. In this work, we present a first-principles approach to calculating the charge transfer. Based on the effects of perturbations of an individual atom or a group of atoms on the electron charge density, we determine unambiguously the amount of electron charge associated with a particular atom or a group of atoms. We computed the topological electron loss versus gain using ethylene, graphene, MgO, and SrTiO3 as examples. Our results verify the nature of chemical bonds in these materials at the atomic level.

  18. Charge densities and charge noise in mesoscopic conductors

    Indian Academy of Sciences (India)

    M Büttiker

    2002-02-01

    We introduce a hierarchy of density of states to characterize the charge distribution in a mesoscopic conductor. At the bottom of this hierarchy are the partial density of states which represent the contribution to the local density of states if both the incident and the out-going scattering channel is prescribed. The partial density of states play a prominent role in measurements with a scanning tunneling microscope on multiprobe conductors in the presence of current flow. The partial density of states determine the degree of dephasing generated by a weakly coupled voltage probe. In addition the partial density of states determine the frequency-dependent response of mesoscopic conductors in the presence of slowly oscillating voltages applied to the contacts of the sample. The partial density of states permit the formulation of a Friedel sum rule which can be applied locally. We introduce the off-diagonal elements of the partial density of states matrix to describe charge fluctuation processes. This generalization leads to a local Wigner–Smith life-time matrix.

  19. Quantum crystallographic charge density of urea

    Directory of Open Access Journals (Sweden)

    Michael E. Wall

    2016-07-01

    Full Text Available Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement.

  20. Quantum crystallographic charge density of urea.

    Science.gov (United States)

    Wall, Michael E

    2016-07-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement.

  1. Quantum crystallographic charge density of urea

    Science.gov (United States)

    Wall, Michael E.

    2016-01-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement. PMID:27437111

  2. Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density.

    Science.gov (United States)

    Son, In Hyuk; Hwan Park, Jong; Kwon, Soonchul; Park, Seongyong; Rümmeli, Mark H; Bachmatiuk, Alicja; Song, Hyun Jae; Ku, Junhwan; Choi, Jang Wook; Choi, Jae-Man; Doo, Seok-Gwang; Chang, Hyuk

    2015-06-25

    Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l(-1) at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology.

  3. Microfabricated pseudocapacitors using Ni(OH)2 electrodes exhibit remarkable volumetric capacitance and energy density

    KAUST Repository

    Kurra, Narendra

    2014-09-10

    Metal hydroxide based microfabricated pseudocapacitors with impressive volumetric stack capacitance and energy density are demonstrated. A combination of top-down photolithographic process and bottom-up chemical synthesis is employed to fabricate the micro-pseudocapacitors (μ-pseudocapacitors). The resulting Ni(OH)2-based devices show several excellent characteristics including high-rate redox activity up to 500 V s-1 and an areal cell capacitance of 16 mF cm-2 corresponding to a volumetric stack capacitance of 325 F cm-3. This volumetric capacitance is two-fold higher than carbon and metal oxide based μ-supercapacitors with interdigitated electrode architecture. Furthermore, these μ-pseudocapacitors show a maximum energy density of 21 mWh cm-3, which is superior to the Li-based thin film batteries. The heterogeneous growth of Ni(OH)2 over the Ni surface during the chemical bath deposition is found to be the key parameter in the formation of uniform monolithic Ni(OH)2 mesoporous nanosheets with vertical orientation, responsible for the remarkable properties of the fabricated devices. Additionally, functional tandem configurations of the μ-pseudocapacitors are shown to be capable of powering a light-emitting diode.

  4. Competition between superconductivity and charge density waves

    Science.gov (United States)

    Kim, Ki-Seok

    2007-02-01

    We derive an effective field theory for the competition between superconductivity (SC) and charge density waves (CDWs) by employing the SO(3) pseudospin representation of the SC and CDW order parameters. One important feature in the effective nonlinear σ model is the emergence of a Berry phase even at half filling, originating from the competition between SC and CDWs, i.e., the pseudospin symmetry. A-well known conflict between the previous studies of Oshikawa [Phys. Rev. Lett. 84, 1535 (2000)] and Lee and Shankar [Phys. Rev. Lett. 65, 1490 (1990)] is resolved by the appearance of the Berry phase. The Berry phase contribution allows a deconfined quantum critical point of fractionalized charge excitations with e instead of 2e in the SC-CDW quantum transition at half filling. Furthermore, we investigate the stability of the deconfined quantum criticality against quenched randomness by performing a renormalization group analysis of an effective vortex action. We argue that, although randomness results in a weak disorder fixed point differing from the original deconfined quantum critical point, deconfinement of the fractionalized charge excitations still survives at the disorder fixed point owing to a nonzero fixed point value of the vortex charge.

  5. Thermoelectric studies of charge density wave dynamics.

    Science.gov (United States)

    McDonald, Ross; Harrison, Neil; Singleton, John

    2008-03-01

    The conventional pyroelectric effect is intimately connected to the symmetry, or rather lack of center of symmetry, of the material. Although the experiments we discuss involve studies of low symmetry materials, the pyroelectric currents observed are of an entirely new origin. Systems with broken-translational-symmetry phases that incorporate orbital quantization can exhibit significant departures from thermodynamic equilibrium due to a change in magnetic induction. For charge density wave systems, this metastable state consists of a balance between the density-wave pinning force and the Lorentz force on the extended currents due to the drift of cyclotron orbits. In this way the density wave pinning potential plays a similar role to the edge potential in a two-dimensional electron gas, leading to a large Hall angle and quantization of the Hall resistance. A thermal perturbation that reduces the pinning potential returns the system towards thermal equilibrium, via a phason avalanche orthogonal to the sample surface. The observation of this new form of pyroelectric effect in the high magnetic field phase (B > 30 T) of the organic charge transfer salt α-(BEDT-TTF)2KHg(SCN)4, thus provides a measure of the phason thermopower.

  6. Area and volumetric density estimation in processed full-field digital mammograms for risk assessment of breast cancer.

    Directory of Open Access Journals (Sweden)

    Abbas Cheddad

    Full Text Available INTRODUCTION: Mammographic density, the white radiolucent part of a mammogram, is a marker of breast cancer risk and mammographic sensitivity. There are several means of measuring mammographic density, among which are area-based and volumetric-based approaches. Current volumetric methods use only unprocessed, raw mammograms, which is a problematic restriction since such raw mammograms are normally not stored. We describe fully automated methods for measuring both area and volumetric mammographic density from processed images. METHODS: The data set used in this study comprises raw and processed images of the same view from 1462 women. We developed two algorithms for processed images, an automated area-based approach (CASAM-Area and a volumetric-based approach (CASAM-Vol. The latter method was based on training a random forest prediction model with image statistical features as predictors, against a volumetric measure, Volpara, for corresponding raw images. We contrast the three methods, CASAM-Area, CASAM-Vol and Volpara directly and in terms of association with breast cancer risk and a known genetic variant for mammographic density and breast cancer, rs10995190 in the gene ZNF365. Associations with breast cancer risk were evaluated using images from 47 breast cancer cases and 1011 control subjects. The genetic association analysis was based on 1011 control subjects. RESULTS: All three measures of mammographic density were associated with breast cancer risk and rs10995190 (p0.10 for risk, p>0.03 for rs10995190. CONCLUSIONS: Our results show that it is possible to obtain reliable automated measures of volumetric and area mammographic density from processed digital images. Area and volumetric measures of density on processed digital images performed similar in terms of risk and genetic association.

  7. Expanding the reduced-current approach for thermoelectric generators to achieve higher volumetric power density

    DEFF Research Database (Denmark)

    Wijesooriyage, Waruna Dissanayaka; Rosendahl, Lasse

    2015-01-01

    Thermoelectrics are candidate niche electrical generator devices for energy management. At present, scientists are more focused on thermoelectric (TE) material development, but the TE module design procedure is still in a relatively virgin state. One of the most well-known methods is the reduced...... current approach (RCA) for TE module design, where the same current is induced through the p and n legs of the thermoelectric generator (TEG). The current density of each element is manipulated by changing the area of both legs. This technique leads to a TE module architecture based on the most efficient...... configuration of both p and n legs. In the current paper, we apply an extended version of this technique, to show how a TE module with a higher volumetric power density can be designed, compared to the original RCA. Our studies indicate that for some combinations of p and n material properties, optima yielding...

  8. Charge Exchange Effect on Space-Charge-Limited Current Densities in Ion Diode

    Institute of Scientific and Technical Information of China (English)

    石磊

    2002-01-01

    The article theoretically studied the charge-exchange effects on space charge limited electron and ion current densities of non-relativistic one-dimensional slab ion diode, and compared with those of without charge exchange.

  9. An experimental charge density of HEPES.

    Science.gov (United States)

    Sledź, Paweł; Kamiński, Radosław; Chruszcz, Maksymilian; Zimmerman, Matthew D; Minor, Wladek; Woźniak, Krzysztof

    2010-08-01

    We report the experimental charge density of HEPES [4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid], which is a common buffering agent. The structure was refined using the Hansen-Coppens formalism. The ability of the HEPES molecule to form stable intermolecular interactions and intermolecular hydrogen bonds in the crystal structure is discussed in terms of its buffering properties. The protonation mode observed in the crystal structure is different from that expected in solution, suggesting that additional factors must be taken into consideration in order to explain the solution properties of the compound. As ordered HEPES molecules are found in the active sites of proteins in several protein crystal structures, our results will allow for quantitative analysis of the electrostatic potential of the interacting surfaces of those proteins.

  10. Mammographic Breast Density Assessment Using Automated Volumetric Software and Breast Imaging Reporting and Data System (BIRADS) Categorization by Expert Radiologists.

    Science.gov (United States)

    Damases, Christine N; Brennan, Patrick C; Mello-Thoms, Claudia; McEntee, Mark F

    2016-01-01

    To investigate agreement on mammographic breast density (MD) assessment between automated volumetric software and Breast Imaging Reporting and Data System (BIRADS) categorization by expert radiologists. Forty cases of left craniocaudal and mediolateral oblique mammograms from 20 women were used. All images had their volumetric density classified using Volpara density grade (VDG) and average volumetric breast density percentage. The same images were then classified into BIRADS categories (I-IV) by 20 American Board of Radiology examiners. The results demonstrated a moderate agreement (κ = 0.537; 95% CI = 0.234-0.699) between VDG classification and radiologists' BIRADS density assessment. Interreader agreement using BIRADS also demonstrated moderate agreement (κ = 0.565; 95% CI = 0.519-0.610) ranging from 0.328 to 0.669. Radiologists' average BIRADS was lower than average VDG scores by 0.33, with their mean being 2.13, whereas the mean VDG was 2.48 (U = -3.742; P BIRADS showed a very strong positive correlation (ρ = 0.91; P BIRADS and average volumetric breast density percentage (ρ = 0.94; P BIRADS; interreader variations still exist within BIRADS. Because of the increasing importance of MD measurement in clinical management of patients, widely accepted, reproducible, and accurate measures of MD are required. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  11. Role of 17 beta-estradiol on type IV collagen fibers volumetric density in the basement membrane of bladder wall.

    Science.gov (United States)

    de Fraga, Rogerio; Dambros, Miriam; Miyaoka, Ricardo; Riccetto, Cássio Luís Zanettini; Palma, Paulo César Rodrigues

    2007-10-01

    The authors quantified the type IV collagen fibers volumetric density in the basement membrane of bladder wall of ovariectomized rats with and without estradiol replacement. This study was conducted on 40 Wistar rats (3 months old) randomly divided in 4 groups: group 1, remained intact (control); group 2, submitted to bilateral oophorectomy and daily replacement 4 weeks later of 17 beta-estradiol for 12 weeks; group 3, sham operated and daily replacement 4 weeks later of sesame oil for 12 weeks; and group 4, submitted to bilateral oophorectomy and killed after 12 weeks. It was used in immunohistochemistry evaluation using type IV collagen polyclonal antibody to stain the fibers on paraffin rat bladder sections. The M-42 stereological grid system was used to analyze the fibers. Ovariectomy had an increase effect on the volumetric density of the type IV collagen fibers in the basement membrane of rat bladder wall. Estradiol replacement in castrated animals demonstrated a significative difference in the stereological parameters when compared to the castrated group without hormonal replacement. Surgical castration performed on rats induced an increasing volumetric density of type IV collagen fibers in the basement membrane of rats bladder wall and the estradiol treatment had a significant effect in keeping a low volumetric density of type IV collagen fibers in the basement membrane of rats bladder wall.

  12. Rhodium dihydride (RhH2) with high volumetric hydrogen density.

    Science.gov (United States)

    Li, Bing; Ding, Yang; Kim, Duck Young; Ahuja, Rajeev; Zou, Guangtian; Mao, Ho-Kwang

    2011-11-15

    Materials with very high hydrogen density have attracted considerable interest due to a range of motivations, including the search for chemically precompressed metallic hydrogen and hydrogen storage applications. Using high-pressure synchrotron X-ray diffraction technique and theoretical calculations, we have discovered a new rhodium dihydride (RhH(2)) with high volumetric hydrogen density (163.7 g/L). Compressing rhodium in fluid hydrogen at ambient temperature, the fcc rhodium metal absorbs hydrogen and expands unit-cell volume by two discrete steps to form NaCl-typed fcc rhodium monohydride at 4 GPa and fluorite-typed fcc RhH(2) at 8 GPa. RhH(2) is the first dihydride discovered in the platinum group metals under high pressure. Our low-temperature experiments show that RhH(2) is recoverable after releasing pressure cryogenically to 1 bar and is capable of retaining hydrogen up to 150 K for minutes and 77 K for an indefinite length of time.

  13. How Precise Is Dental Volumetric Tomography in the Prediction of Bone Density?

    Directory of Open Access Journals (Sweden)

    Hakan Bilhan

    2012-01-01

    Full Text Available Objectives. The aim of this study was to review the bone density assessment techniques and evaluate the macroscopic structure of bone specimens scored by Hounsfield Units (HUs and decide if they are always in congruence. Methods. The mandible of a formalin-fixed human cadaver was scanned by dental volumetric tomography (DVT for planning of the specimen positions and fabrication of a surgical guide and a surgical stent was fabricated afterwards. Bone cylinders of 3.5 mm diameter and 5 mm length, were excised from the mandible using the surgical stent with a slow speed trephine drill. After removal of the cylinders two more scans were performed and the images of the first scan were used for the determination of the HU values. The removed bone cylinder was inspected macroscopically as well by micro-CT scan. Results. The highest HU values were recorded in the interforaminal region, especially in the midline (408–742. Posterior regions showed lower HU values, especially the first molar regions (22–61 for the right; 14–66 for the left first molar regions. Conclusion. Within the limitations of this pilot study, it can be concluded that HU values alone could be a misleading diagnostic tool for the determination of bone density.

  14. Rhodium dihydride (RhH2) with high volumetric hydrogen density

    Science.gov (United States)

    Li, Bing; Ding, Yang; Kim, Duck Young; Ahuja, Rajeev; Zou, Guangtian; Mao, Ho-Kwang

    2011-01-01

    Materials with very high hydrogen density have attracted considerable interest due to a range of motivations, including the search for chemically precompressed metallic hydrogen and hydrogen storage applications. Using high-pressure synchrotron X-ray diffraction technique and theoretical calculations, we have discovered a new rhodium dihydride (RhH2) with high volumetric hydrogen density (163.7 g/L). Compressing rhodium in fluid hydrogen at ambient temperature, the fcc rhodium metal absorbs hydrogen and expands unit-cell volume by two discrete steps to form NaCl-typed fcc rhodium monohydride at 4 GPa and fluorite-typed fcc RhH2 at 8 GPa. RhH2 is the first dihydride discovered in the platinum group metals under high pressure. Our low-temperature experiments show that RhH2 is recoverable after releasing pressure cryogenically to 1 bar and is capable of retaining hydrogen up to 150 K for minutes and 77 K for an indefinite length of time. PMID:22039219

  15. Comparing Visually Assessed BI-RADS Breast Density and Automated Volumetric Breast Density Software: A Cross-Sectional Study in a Breast Cancer Screening Setting.

    Directory of Open Access Journals (Sweden)

    Daniëlle van der Waal

    Full Text Available The objective of this study is to compare different methods for measuring breast density, both visual assessments and automated volumetric density, in a breast cancer screening setting. These measures could potentially be implemented in future screening programmes, in the context of personalised screening or screening evaluation.Digital mammographic exams (N = 992 of women participating in the Dutch breast cancer screening programme (age 50-75y in 2013 were included. Breast density was measured in three different ways: BI-RADS density (5th edition and with two commercially available automated software programs (Quantra and Volpara volumetric density. BI-RADS density (ordinal scale was assessed by three radiologists. Quantra (v1.3 and Volpara (v1.5.0 provide continuous estimates. Different comparison methods were used, including Bland-Altman plots and correlation coefficients (e.g., intraclass correlation coefficient [ICC].Based on the BI-RADS classification, 40.8% of the women had 'heterogeneously or extremely dense' breasts. The median volumetric percent density was 12.1% (IQR: 9.6-16.5 for Quantra, which was higher than the Volpara estimate (median 6.6%, IQR: 4.4-10.9. The mean difference between Quantra and Volpara was 5.19% (95% CI: 5.04-5.34 (ICC: 0.64. There was a clear increase in volumetric percent dense volume as BI-RADS density increased. The highest accuracy for predicting the presence of BI-RADS c+d (heterogeneously or extremely dense was observed with a cut-off value of 8.0% for Volpara and 13.8% for Quantra.Although there was no perfect agreement, there appeared to be a strong association between all three measures. Both volumetric density measures seem to be usable in breast cancer screening programmes, provided that the required data flow can be realized.

  16. Freezing of low energy excitations in charge density wave glasses.

    Science.gov (United States)

    Staresinic, D; Zaitsev-Zotov, S V; Baklanov, N I; Biljaković, K

    2008-03-07

    Thermally stimulated discharge current measurements were performed to study slow relaxation processes in two canonical charge density wave systems K(0.3)MoO(3) and o-TaS(3). Two relaxation processes were observed and characterized in each system, corroborating the results of dielectric spectroscopy. Our results are consistent with the scenario of the glass transition on the charge density wave superstructure level. In particular, the results directly prove the previously proposed criterion of charge density wave freezing based on the interplay of charge density wave pinning by impurities and screening by free carriers. In addition, we obtained new information on distribution of relaxation parameters, as well as on nonlinear dielectric response both below and above the threshold field for charge density wave sliding.

  17. Volumetric magnetic resonance imaging classification for Alzheimer's disease based on kernel density estimation of local features

    Institute of Scientific and Technical Information of China (English)

    YAN Hao; WANG Hu; WANG Yong-hui; ZHANG Yu-mei

    2013-01-01

    Background The classification of Alzheimer's disease (AD) from magnetic resonance imaging (MRI) has been challenged by lack of effective and reliable biomarkers due to inter-subject variability.This article presents a classification method for AD based on kernel density estimation (KDE) of local features.Methods First,a large number of local features were extracted from stable image blobs to represent various anatomical patterns for potential effective biomarkers.Based on distinctive descriptors and locations,the local features were robustly clustered to identify correspondences of the same underlying patterns.Then,the KDE was used to estimate distribution parameters of the correspondences by weighting contributions according to their distances.Thus,biomarkers could be reliably quantified by reducing the effects of further away correspondences which were more likely noises from inter-subject variability.Finally,the Bayes classifier was applied on the distribution parameters for the classification of AD.Results Experiments were performed on different divisions of a publicly available database to investigate the accuracy and the effects of age and AD severity.Our method achieved an equal error classification rate of 0.85 for subject aged 60-80 years exhibiting mild AD and outperformed a recent local feature-based work regardless of both effects.Conclusions We proposed a volumetric brain MRI classification method for neurodegenerative disease based on statistics of local features using KDE.The method may be potentially useful for the computer-aided diagnosis in clinical settings.

  18. Charge density fluctuation of low frequency in a dusty plasma

    Institute of Scientific and Technical Information of China (English)

    李芳; 吕保维; O.Havnes

    1997-01-01

    The charge density fluctuation of low frequency in a dusty plasma, which is derived from the longitudinal dielectric permittivity of the dusty plasma, has been studied by kinetic theory. The results show that the P value, which describes the relative charge density on the dust in the plasma, and the charging frequency of a dust particle Ωc, which describes the ratio of charge changing of the dust particles, determine the character of the charge density fluctuation of low frequency. For a dusty plasma of P<<1, when the charging frequency Ωc is much smaller than the dusty plasma frequency wd, there is a strong charge density fluctuation which is of character of dust acoustic eigen wave. For a dusty plasma of P>>1, when the frequency Ωc, is much larger than wd there are weaker fluctuations with a wide spectrum. The results have been applied to the ionosphere and the range of radius and density of dust particles is found, where a strong charge density fluctuation of low frequency should exist.

  19. Tibia and radius bone geometry and volumetric density in obese compared to non-obese adolescents.

    Science.gov (United States)

    Leonard, Mary B; Zemel, Babette S; Wrotniak, Brian H; Klieger, Sarah B; Shults, Justine; Stallings, Virginia A; Stettler, Nicolas

    2015-04-01

    Childhood obesity is associated with biologic and behavioral characteristics that may impact bone mineral density (BMD) and structure. The objective was to determine the association between obesity and bone outcomes, independent of sexual and skeletal maturity, muscle area and strength, physical activity, calcium intake, biomarkers of inflammation, and vitamin D status. Tibia and radius peripheral quantitative CT scans were obtained in 91 obese (BMI>97th percentile) and 51 non-obese adolescents (BMI>5th and Tibia cortical section modulus and calf muscle area Z-scores were greater in obese participants (1.07 and 1.63, respectively, both pTibia and radius trabecular and cortical volumetric BMD did not differ significantly between groups. Calf muscle area and strength Z-scores, advanced skeletal maturity, and physical activity (by accelerometry) were positively associated with tibia cortical section modulus Z-scores (all ptibia section modulus Z-scores between obese and non-obese participants from 1.07 to 0.28. After multivariate adjustment for greater calf muscle area and strength Z-scores, advanced maturity, and less moderate to vigorous physical activity, tibia section modulus Z-scores were 0.32 (95% CI -0.18, 0.43, p=0.06) greater in obese, vs. non-obese participants. Radius cortical section modulus Z-scores were 0.45 greater (p=0.08) in obese vs. non-obese participants; this difference was attenuated to 0.14 with adjustment for advanced maturity. These findings suggest that greater tibia cortical section modulus in obese adolescents is attributable to advanced skeletal maturation and greater muscle area and strength, while less moderate to vigorous physical activities offset the positive effects of these covariates. The impact of obesity on cortical structure was greater at weight bearing sites.

  20. Ultrathin, Lightweight, and Wearable Li-O2 Battery with High Robustness and Gravimetric/Volumetric Energy Density.

    Science.gov (United States)

    Liu, Tong; Xu, Ji-Jing; Liu, Qing-Chao; Chang, Zhi-Wen; Yin, Yan-Bin; Yang, Xiao-Yang; Zhang, Xin-Bo

    2017-02-01

    An ultrathin, lightweight, and wearable Li-O2 battery with a novel segmented structure is first fabricated by employing a "break up the whole into parts" strategy. Superior battery performance including low overpotential, high specific capacity, good rate capability, excellent cycle stability, and high gravimetric/volumetric energy density (294.68 Wh kg(-1) /274.06 Wh L(-1) ) is successfully achieved even under repeatedly various deformation.

  1. Improved correlation between CT emphysema quantification and pulmonary function test by density correction of volumetric CT data based on air and aortic density

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Song Soo [Department of Radiology, Chungnam National University Hospital, Chungnam National University School of Medicine (Korea, Republic of); Seo, Joon Beom, E-mail: seojb@amc.seoul.kr [Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of); Kim, Namkug; Chae, Eun Jin [Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of); Lee, Young Kyung [Department of Radiology, Kyung Hee University Hospital at Gangdong (Korea, Republic of); Oh, Yeon Mok; Lee, Sang Do [Division of Pulmonology, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center (Korea, Republic of)

    2014-01-15

    Objectives: To determine the improvement of emphysema quantification with density correction and to determine the optimal site to use for air density correction on volumetric computed tomography (CT). Methods: Seventy-eight CT scans of COPD patients (GOLD II–IV, smoking history 39.2 ± 25.3 pack-years) were obtained from several single-vendor 16-MDCT scanners. After density measurement of aorta, tracheal- and external air, volumetric CT density correction was conducted (two reference values: air, −1000 HU/blood, +50 HU). Using in-house software, emphysema index (EI) and mean lung density (MLD) were calculated. Differences in air densities, MLD and EI prior to and after density correction were evaluated (paired t-test). Correlation between those parameters and FEV{sub 1} and FEV{sub 1}/FVC were compared (age- and sex adjusted partial correlation analysis). Results: Measured densities (HU) of tracheal- and external air differed significantly (−990 ± 14, −1016 ± 9, P < 0.001). MLD and EI on original CT data, after density correction using tracheal- and external air also differed significantly (MLD: −874.9 ± 27.6 vs. −882.3 ± 24.9 vs. −860.5 ± 26.6; EI: 16.8 ± 13.4 vs. 21.1 ± 14.5 vs. 9.7 ± 10.5, respectively, P < 0.001). The correlation coefficients between CT quantification indices and FEV{sub 1}, and FEV{sub 1}/FVC increased after density correction. The tracheal air correction showed better results than the external air correction. Conclusion: Density correction of volumetric CT data can improve correlations of emphysema quantification and PFT.

  2. WSN-Based Space Charge Density Measurement System.

    Science.gov (United States)

    Deng, Dawei; Yuan, Haiwen; Lv, Jianxun; Ju, Yong

    2017-01-01

    It is generally acknowledged that high voltage direct current (HVDC) transmission line endures the drawback of large area, because of which the utilization of cable for space charge density monitoring system is of inconvenience. Compared with the traditional communication network, wireless sensor network (WSN) shows advantages in small volume, high flexibility and strong self-organization, thereby presenting great potential in solving the problem. Additionally, WSN is more suitable for the construction of distributed space charge density monitoring system as it has longer distance and higher mobility. A distributed wireless system is designed for collecting and monitoring the space charge density under HVDC transmission lines, which has been widely applied in both Chinese state grid HVDC test base and power transmission projects. Experimental results of the measuring system demonstrated its adaptability in the complex electromagnetic environment under the transmission lines and the ability in realizing accurate, flexible, and stable demands for the measurement of space charge density.

  3. VARIOUS REGIMES OF CHARGE-DENSITY WAVES IN LAYERED COMPOUNDS

    NARCIS (Netherlands)

    Bakel, G.P.E.M. van; Hosson, J.Th.M. De

    1992-01-01

    In this paper we have subjected different layered transition-metal dichalcogenides to scanning tunneling microscopy to reveal the electronic charge distribution associated with the charge-density-wave (CDW) part of the superstructure, in addition to the atomic corrugation. The observations presented

  4. Genetic determinants of trabecular and cortical volumetric bone mineral densities and bone microstructure.

    Directory of Open Access Journals (Sweden)

    Lavinia Paternoster

    Full Text Available Most previous genetic epidemiology studies within the field of osteoporosis have focused on the genetics of the complex trait areal bone mineral density (aBMD, not being able to differentiate genetic determinants of cortical volumetric BMD (vBMD, trabecular vBMD, and bone microstructural traits. The objective of this study was to separately identify genetic determinants of these bone traits as analysed by peripheral quantitative computed tomography (pQCT. Separate GWA meta-analyses for cortical and trabecular vBMDs were performed. The cortical vBMD GWA meta-analysis (n = 5,878 followed by replication (n = 1,052 identified genetic variants in four separate loci reaching genome-wide significance (RANKL, rs1021188, p = 3.6×10⁻¹⁴; LOC285735, rs271170, p = 2.7×10⁻¹²; OPG, rs7839059, p = 1.2×10⁻¹⁰; and ESR1/C6orf97, rs6909279, p = 1.1×10⁻⁹. The trabecular vBMD GWA meta-analysis (n = 2,500 followed by replication (n = 1,022 identified one locus reaching genome-wide significance (FMN2/GREM2, rs9287237, p = 1.9×10⁻⁹. High-resolution pQCT analyses, giving information about bone microstructure, were available in a subset of the GOOD cohort (n = 729. rs1021188 was significantly associated with cortical porosity while rs9287237 was significantly associated with trabecular bone fraction. The genetic variant in the FMN2/GREM2 locus was associated with fracture risk in the MrOS Sweden cohort (HR per extra T allele 0.75, 95% confidence interval 0.60-0.93 and GREM2 expression in human osteoblasts. In conclusion, five genetic loci associated with trabecular or cortical vBMD were identified. Two of these (FMN2/GREM2 and LOC285735 are novel bone-related loci, while the other three have previously been reported to be associated with aBMD. The genetic variants associated with cortical and trabecular bone parameters differed, underscoring the complexity of the genetics of bone parameters. We propose

  5. Tibia and radius bone geometry and volumetric density in obese compared to non-obese adolescents☆

    Science.gov (United States)

    Leonard, Mary B.; Zemel, Babette S.; Wrotniak, Brian H.; Klieger, Sarah B.; Shults, Justine; Stallings, Virginia A.; Stettler, Nicolas

    2015-01-01

    Childhood obesity is associated with biologic and behavioral characteristics that may impact bone mineral density (BMD) and structure. The objective was to determine the association between obesity and bone outcomes, independent of sexual and skeletal maturity, muscle area and strength, physical activity, calcium intake, bio-markers of inflammation, and vitamin D status. Tibia and radius peripheral quantitative CT scans were obtained in 91 obese (BMI > 97th percentile) and 51 non-obese adolescents (BMI > 5th and <85th percentiles). Results were converted to sex- and race-specific Z-scores relative to age. Cortical structure, muscle area and muscle strength (by dynamometry) Z-scores were further adjusted for bone length. Obese participants had greater height Z-scores (p < 0.001), and advanced skeletal maturity (p < 0.0001), compared with non-obese participants. Tibia cortical section modulus and calf muscle area Z-scores were greater in obese participants (1.07 and 1.63, respectively, both p < 0.0001). Tibia and radius trabecular and cortical volumetric BMD did not differ significantly between groups. Calf muscle area and strength Z-scores, advanced skeletal maturity, and physical activity (by accelerometry) were positively associated with tibia cortical section modulus Z-scores (all p < 0.01). Adjustment for muscle area Z-score attenuated differences in tibia section modulus Z-scores between obese and non-obese participants from 1.07 to 0.28. After multivariate adjustment for greater calf muscle area and strength Z-scores, advanced maturity, and less moderate to vigorous physical activity, tibia section modulus Z-scores were 0.32 (95% CI −0.18, 0.43, p = 0.06) greater in obese, vs. non-obese participants. Radius cortical section modulus Z-scores were 0.45 greater (p = 0.08) in obese vs. non-obese participants; this difference was attenuated to 0.14 with adjustment for advanced maturity. These findings suggest that greater tibia cortical section modulus in obese

  6. Charge and spin fluctuations in the density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Gyoerffy, B.L.; Barbieri, A. (Bristol Univ. (UK). H.H. Wills Physics Lab.); Staunton, J.B. (Warwick Univ., Coventry (UK). Dept. of Physics); Shelton, W.A.; Stocks, G.M. (Oak Ridge National Lab., TN (USA))

    1990-01-01

    We introduce a conceptual framework which allow us to treat charge and spin fluctuations about the Local density Approximation (LDA) to the Density Functional Theory (DFT). We illustrate the approach by explicit study of the Disordered Local Moment (DLM) state in Fe above the Curie Temperature {Tc} and the Mott insulating state in MnO. 27 refs., 6 figs.

  7. Experimental Evidence for Static Charge Density Waves in Iron Oxypnictides

    KAUST Repository

    Martinelli, A.

    2017-02-01

    In this Letter we report high-resolution synchrotron x-ray powder diffraction and transmission electron microscope analysis of Mn-substituted LaFeAsO samples, demonstrating that a static incommensurate modulated structure develops across the low-temperature orthorhombic phase, whose modulation wave vector depends on the Mn content. The incommensurate structural distortion is likely originating from a charge-density-wave instability, a periodic modulation of the density of conduction electrons associated with a modulation of the atomic positions. Our results add a new component in the physics of Fe-based superconductors, indicating that the density wave ordering is charge driven.

  8. Do plasma proteins distinguish between liposomes of varying charge density?

    KAUST Repository

    Capriotti, Anna Laura

    2012-03-01

    Cationic liposomes (CLs) are one of the most employed nonviral nanovector systems in gene therapy. However, their transfection efficiency is strongly affected by interactions with plasma components, that lead to the formation of a "protein corona" onto CL surface. The interactions between nanoparticles entering the body and biomolecules have an essential role for their biodistribution. Because the knowledge of proteins adsorbed onto vector surface could be useful in the screening of new, more efficient and more biocompatible liposomal formulations, the behavior of three CLs with different membrane charge densities was investigated. The proteins of the three coronas were identified by nano-liquid chromatography-tandem mass spectrometry, and quantified with label-free spectral counting strategy. Fibrinogen displayed higher association with CLs with high membrane charge density, while apolipoproteins and C4b-binding protein with CLs with low membrane charge density. These results are discussed in terms of the different lipid compositions of CLs and may have a deep biological impact for in vivo applications. Surface charge of nanoparticles is emerging as a relevant factor determining the corona composition after interaction with plasma proteins. Remarkably, it is also shown that the charge of the protein corona formed around CLs is strongly related to their membrane charge density. © 2012 Elsevier B.V.

  9. The effect of polymer charge density and charge distribution on the formation of multilayers

    CERN Document Server

    Voigt, U; Tauer, K; Hahn, M; Jäger, W; Klitzing, K V

    2003-01-01

    Polyelectrolyte multilayers which are built up by alternating adsorption of polyanions and polycations from aqueous solutions at a solid interface are investigated by reflectometry and ellipsometry. Below a degree of charge of about 70% the adsorption stops after a certain number of dipping cycles and no multilayer formation occurs. This indicates an electrostatically driven adsorption process. Below a charge density of 70% an adsorption can take place if the charged segments are combined as a block of the polymer.

  10. Nuclear charge radii: Density functional theory meets Bayesian neural networks

    CERN Document Server

    Utama, Raditya; Piekarewicz, Jorge

    2016-01-01

    The distribution of electric charge in atomic nuclei is fundamental to our understanding of the complex nuclear dynamics and a quintessential observable to validate nuclear structure models. We explore a novel approach that combines sophisticated models of nuclear structure with Bayesian neural networks (BNN) to generate predictions for the charge radii of thousands of nuclei throughout the nuclear chart. A class of relativistic energy density functionals is used to provide robust predictions for nuclear charge radii. In turn, these predictions are refined through Bayesian learning for a neural network that is trained using residuals between theoretical predictions and the experimental data. Although predictions obtained with density functional theory provide a fairly good description of experiment, our results show significant improvement (better than 40%) after BNN refinement. Moreover, these improved results for nuclear charge radii are supplemented with theoretical error bars. We have successfully demonst...

  11. The formation of strong electric fields and volumetric charges in the Solar atmosphere

    CERN Document Server

    Sarsembaeva, A T; Kato, K

    2012-01-01

    The processes occurring in the solar atmosphere are diverse and depend on many important factors. For example, from magnetic fields, their sudden changes, from emissions of substance from the depths of the Sun, distribution of shock waves and plasma jets, etc. The paper describes the model of formation of the charged volumes of gas in solar atmosphere, which is called solar "storm clouds" by analogy with terrestrial storm clouds. The model will be based on the theory ionization equilibrium and the Saha equation.

  12. Contributions of charge-density research to medicinal chemistry

    Directory of Open Access Journals (Sweden)

    Birger Dittrich

    2014-11-01

    Full Text Available This article reviews efforts in accurate experimental charge-density studies with relevance to medicinal chemistry. Initially, classical charge-density studies that measure electron density distribution via least-squares refinement of aspherical-atom population parameters are summarized. Next, interaction density is discussed as an idealized situation resembling drug–receptor interactions. Scattering-factor databases play an increasing role in charge-density research, and they can be applied both to small-molecule and macromolecular structures in refinement and analysis; software development facilitates their use. Therefore combining both of these complementary branches of X-ray crystallography is recommended, and examples are given where such a combination already proved useful. On the side of the experiment, new pixel detectors are allowing rapid measurements, thereby enabling both high-throughput small-molecule studies and macromolecular structure determination to higher resolutions. Currently, the most ambitious studies compute intermolecular interaction energies of drug–receptor complexes, and it is recommended that future studies benefit from recent method developments. Selected new developments in theoretical charge-density studies are discussed with emphasis on its symbiotic relation to crystallography.

  13. Breathing Charge Density Waves in Intrinsic Josephson Junctions

    OpenAIRE

    Shukrinov, Yu M.; Abdelhafiz, H.

    2013-01-01

    We demonstrate the creation of a charge density wave (CDW) along a stack of coupled Josephson junctions in layered superconductors. Electric charge in each superconducting layer oscillates around some average value, forming a breathing CDW. We show the transformation of a longitudinal plasma wave to CDW in the state corresponding to the outermost branch. Transitions between different types of CDW's related to the inner branches of current voltage characteristics are demonstrated. The effect o...

  14. Charge density of GaAl1-Sb

    Indian Academy of Sciences (India)

    K B Joshi; Nishant N Patel

    2008-02-01

    Charge density calculations and electronic band structures for GaAl1- = 1.0, 0.5 and 0.0 are presented in this work. The calculations are performed using the empirical pseudopotential method. The charge density is computed for a number of planes, i.e. = 0:0, 0.125 and 0.25 0 by generating the potential through a number of potential parameters available in the literature. The virtual crystal approximation was applied for the semiconducting alloy. The characteristics of the band structure and charge density are observed to be affected by the potential parameters. Calculated band gaps and the nature of gaps are in good agreement with the experimental data reported. The ionicity is also reasonably in good agreement with other scales proposed in the literature; however the formulation needs to be improved. The present work also demands indirect experimental band gap for the alloy.

  15. Nuclear charge radii: density functional theory meets Bayesian neural networks

    Science.gov (United States)

    Utama, R.; Chen, Wei-Chia; Piekarewicz, J.

    2016-11-01

    The distribution of electric charge in atomic nuclei is fundamental to our understanding of the complex nuclear dynamics and a quintessential observable to validate nuclear structure models. The aim of this study is to explore a novel approach that combines sophisticated models of nuclear structure with Bayesian neural networks (BNN) to generate predictions for the charge radii of thousands of nuclei throughout the nuclear chart. A class of relativistic energy density functionals is used to provide robust predictions for nuclear charge radii. In turn, these predictions are refined through Bayesian learning for a neural network that is trained using residuals between theoretical predictions and the experimental data. Although predictions obtained with density functional theory provide a fairly good description of experiment, our results show significant improvement (better than 40%) after BNN refinement. Moreover, these improved results for nuclear charge radii are supplemented with theoretical error bars. We have successfully demonstrated the ability of the BNN approach to significantly increase the accuracy of nuclear models in the predictions of nuclear charge radii. However, as many before us, we failed to uncover the underlying physics behind the intriguing behavior of charge radii along the calcium isotopic chain.

  16. Effect of rhythmic gymnastics on volumetric bone mineral density and bone geometry in premenarcheal female athletes and controls.

    Science.gov (United States)

    Tournis, S; Michopoulou, E; Fatouros, I G; Paspati, I; Michalopoulou, M; Raptou, P; Leontsini, D; Avloniti, A; Krekoukia, M; Zouvelou, V; Galanos, A; Aggelousis, N; Kambas, A; Douroudos, I; Lyritis, G P; Taxildaris, K; Pappaioannou, N

    2010-06-01

    Weight-bearing exercise during growth exerts positive effects on the skeleton. Our objective was to test the hypothesis that long-term elite rhythmic gymnastics exerts positive effects on volumetric bone mineral density and geometry and to determine whether exercise-induced bone adaptation is associated with increased periosteal bone formation or medullary contraction using tibial peripheral quantitative computed tomography and bone turnover markers. We conducted a cross-sectional study at a tertiary center. We studied 26 elite premenarcheal female rhythmic gymnasts (RG) and 23 female controls, aged 9-13 yr. We measured bone age, volumetric bone mineral density, bone mineral content (BMC), cortical thickness, cortical and trabecular area, and polar stress strength index (SSIp) by peripheral quantitative computed tomography of the left tibia proximal to the distal metaphysis (trabecular) at 14, 38 (cortical), and 66% (muscle mass) from the distal end and bone turnover markers. The two groups were comparable according to height and chronological and bone age. After weight adjustment, cortical BMC, area, and thickness at 38% were significantly higher in RG (P < 0.005-0.001). Periosteal circumference, SSIp, and muscle area were higher in RG (P < 0.01-0.001). Muscle area was significantly associated with cortical BMC, area, and SSIp, whereas years of training showed positive association with cortical BMC, area, and thickness independent of chronological age. RG in premenarcheal girls may induce positive adaptations on the skeleton, especially in cortical bone. Increased duration of exercise is associated with a positive response of bone geometry.

  17. Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density

    Science.gov (United States)

    Son, In Hyuk; Hwan Park, Jong; Kwon, Soonchul; Park, Seongyong; Rümmeli, Mark H.; Bachmatiuk, Alicja; Song, Hyun Jae; Ku, Junhwan; Choi, Jang Wook; Choi, Jae-man; Doo, Seok-Gwang; Chang, Hyuk

    2015-01-01

    Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge–discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l−1 at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology. PMID:26109057

  18. Charge density asymmetry of heavy-ion fusion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Poenaru, N.D.; Ivascu, M.; Mazilu, D.; Sandulescu, A. (Institutul de Fizica si Inginerie Nucleara, Bucharest (Romania))

    1980-01-01

    The generalized liquid-drop model replacing surface energy by double folded Yukawa-plus-exponential function is extended for fusion of heavy ions with different charge densities. Calculated interaction barriers for some 58 pairs of nuclei are in good agreement with experimental ones, within -10% and +7%. For even-even beta-stable nuclei with Z =4-104 the general trend of variation of interaction barriers and fusion Q-values show the regions where the charge density asymmetry cannot be neglected. PES for the entrance channel of the reactions /sup 109/Ag + /sup 40/Ar, /sup 138/Ce + /sup 57/Fe, /sup 144/Nd + /sup 84/Kr and the corresponding charge-equilibrated system have been computed.

  19. Transition metal sulfides grown on graphene fibers for wearable asymmetric supercapacitors with high volumetric capacitance and high energy density

    Science.gov (United States)

    Cai, Weihua; Lai, Ting; Lai, Jianwei; Xie, Haoting; Ouyang, Liuzhang; Ye, Jianshan; Yu, Chengzhong

    2016-06-01

    Fiber shaped supercapacitors are promising candidates for wearable electronics because they are flexible and light-weight. However, a critical challenge of the widespread application of these energy storage devices is their low cell voltages and low energy densities, resulting in limited run-time of the electronics. Here, we demonstrate a 1.5 V high cell voltage and high volumetric energy density asymmetric fiber supercapacitor in aqueous electrolyte. The lightweight (0.24 g cm‑3), highly conductive (39 S cm‑1), and mechanically robust (221 MPa) graphene fibers were firstly fabricated and then coated by NiCo2S4 nanoparticles (GF/NiCo2S4) via the solvothermal deposition method. The GF/NiCo2S4 display high volumetric capacitance up to 388 F cm‑3 at 2 mV s‑1 in a three-electrode cell and 300 F cm‑3 at 175.7 mA cm‑3 (568 mF cm‑2 at 0.5 mA cm‑2) in a two-electrode cell. The electrochemical characterizations show 1000% higher capacitance of the GF/NiCo2S4 as compared to that of neat graphene fibers. The fabricated device achieves high energy density up to 12.3 mWh cm‑3 with a maximum power density of 1600 mW cm‑3, outperforming the thin-film lithium battery. Therefore, these supercapacitors are promising for the next generation flexible and wearable electronic devices.

  20. Transition metal sulfides grown on graphene fibers for wearable asymmetric supercapacitors with high volumetric capacitance and high energy density.

    Science.gov (United States)

    Cai, Weihua; Lai, Ting; Lai, Jianwei; Xie, Haoting; Ouyang, Liuzhang; Ye, Jianshan; Yu, Chengzhong

    2016-06-01

    Fiber shaped supercapacitors are promising candidates for wearable electronics because they are flexible and light-weight. However, a critical challenge of the widespread application of these energy storage devices is their low cell voltages and low energy densities, resulting in limited run-time of the electronics. Here, we demonstrate a 1.5 V high cell voltage and high volumetric energy density asymmetric fiber supercapacitor in aqueous electrolyte. The lightweight (0.24 g cm(-3)), highly conductive (39 S cm(-1)), and mechanically robust (221 MPa) graphene fibers were firstly fabricated and then coated by NiCo2S4 nanoparticles (GF/NiCo2S4) via the solvothermal deposition method. The GF/NiCo2S4 display high volumetric capacitance up to 388 F cm(-3) at 2 mV s(-1) in a three-electrode cell and 300 F cm(-3) at 175.7 mA cm(-3) (568 mF cm(-2) at 0.5 mA cm(-2)) in a two-electrode cell. The electrochemical characterizations show 1000% higher capacitance of the GF/NiCo2S4 as compared to that of neat graphene fibers. The fabricated device achieves high energy density up to 12.3 mWh cm(-3) with a maximum power density of 1600 mW cm(-3), outperforming the thin-film lithium battery. Therefore, these supercapacitors are promising for the next generation flexible and wearable electronic devices.

  1. C library for topological study of the electronic charge density.

    Science.gov (United States)

    Vega, David; Aray, Yosslen; Rodríguez, Jesús

    2012-12-05

    The topological study of the electronic charge density is useful to obtain information about the kinds of bonds (ionic or covalent) and the atom charges on a molecule or crystal. For this study, it is necessary to calculate, at every space point, the electronic density and its electronic density derivatives values up to second order. In this work, a grid-based method for these calculations is described. The library, implemented for three dimensions, is based on a multidimensional Lagrange interpolation in a regular grid; by differentiating the resulting polynomial, the gradient vector, the Hessian matrix and the Laplacian formulas were obtained for every space point. More complex functions such as the Newton-Raphson method (to find the critical points, where the gradient is null) and the Cash-Karp Runge-Kutta method (used to make the gradient paths) were programmed. As in some crystals, the unit cell has angles different from 90°, the described library includes linear transformations to correct the gradient and Hessian when the grid is distorted (inclined). Functions were also developed to handle grid containing files (grd from DMol® program, CUBE from Gaussian® program and CHGCAR from VASP® program). Each one of these files contains the data for a molecular or crystal electronic property (such as charge density, spin density, electrostatic potential, and others) in a three-dimensional (3D) grid. The library can be adapted to make the topological study in any regular 3D grid by modifying the code of these functions.

  2. Charge density study of two FeS2 polymorphs

    DEFF Research Database (Denmark)

    Schmøkel, Mette Stokkebro; Jørgensen, Mads Ry Vogel; Bjerg, Lasse

    Experimental charge density studies of inorganic solids have proven to be a difficult task due to systematic errors related to data collection such as absorption and extinction; however, the use of synchrotron radiation has the potential to minimize these problems. [1] One of the pioneering...... experimental electron density studies of an inorganic solid containing a transition metal was presented by Stevens et al. [2] who investigated the effect of crystal-field splitting of the partially filled iron d-orbitals in the pyrite structure of FeS2. Other studies of various FeS2 structures, including...... pyrite, has been performed by Gibbs et al. [3], however, these are all based on theoretical calculations rather than experiment. In the current study we revisit FeS2 through an experimental charge density study of the two low-spin iron FeS2 structures, pyrite and marcasite. High-quality, low...

  3. Determination of Transverse Charge Density from Kaon Form Factor Data

    Science.gov (United States)

    Mejia-Ott, Johann; Horn, Tanja; Pegg, Ian; Mecholski, Nicholas; Carmignotto, Marco; Ali, Salina

    2016-09-01

    At the level of nucleons making up atomic nuclei, among subatomic particles made up of quarks, K-mesons or kaons represent the most simple hadronic system including the heavier strange quark, having a relatively elementary bound state of a quark and an anti-quark as its valence structure. Its electromagnetic structure is then parametrized by a single, dimensionless quantity known as the form factor, the two-dimensional Fourier transform of which yields the quantity of transverse charge density. Transverse charge density, in turn, provides a needed framework for the interpretation of form factors in terms of physical charge and magnetization, both with respect to the propagation of a fast-moving nucleon. To this is added the value of strange quarks in ultimately presenting a universal, process-independent description of nucleons, further augmenting the importance of studying the kaon's internal structure. The pressing character of such research questions directs the present paper, describing the first extraction of transverse charge density from electromagnetic kaon form factor data. The extraction is notably extended to form factor data at recently acquired higher energy levels, whose evaluation could permit more complete phenomenological models for kaon behavior to be proposed. This work was supported in part by NSF Grant PHY-1306227.

  4. Volumetric breast density from full-field digital mammograms and its association with breast cancer risk factors: a comparison with a threshold method.

    NARCIS (Netherlands)

    Lokate, M.; Kallenberg, M.G.J.; Karssemeijer, N.; Bosch, M.H.J. van den; Peeters, P.H.M.; Gils, C.H. van

    2010-01-01

    INTRODUCTION: Breast density, a strong breast cancer risk factor, is usually measured on the projected breast area from film screen mammograms. This is far from ideal, as breast thickness and technical characteristics are not taken into account. We investigated whether volumetric density measurement

  5. Charge transfer in time-dependent density functional theory

    Science.gov (United States)

    Maitra, Neepa T.

    2017-10-01

    Charge transfer plays a crucial role in many processes of interest in physics, chemistry, and bio-chemistry. In many applications the size of the systems involved calls for time-dependent density functional theory (TDDFT) to be used in their computational modeling, due to its unprecedented balance between accuracy and efficiency. However, although exact in principle, in practise approximations must be made for the exchange-correlation functional in this theory, and the standard functional approximations perform poorly for excitations which have a long-range charge-transfer component. Intense progress has been made in developing more sophisticated functionals for this problem, which we review. We point out an essential difference between the properties of the exchange-correlation kernel needed for an accurate description of charge-transfer between open-shell fragments and between closed-shell fragments. We then turn to charge-transfer dynamics, which, in contrast to the excitation problem, is a highly non-equilibrium, non-perturbative, process involving a transfer of one full electron in space. This turns out to be a much more challenging problem for TDDFT functionals. We describe dynamical step and peak features in the exact functional evolving over time, that are missing in the functionals currently used. The latter underestimate the amount of charge transferred and manifest a spurious shift in the charge transfer resonance position. We discuss some explicit examples.

  6. Survival of charged rho condensation at high temperature and density

    CERN Document Server

    Liu, Hao; Huang, Mei

    2015-01-01

    The charged vector $\\rho$ mesons in the presence of external magnetic fields at finite temperature $T$ and chemical potential $\\mu$ have been investigated in the framework of the Nambu--Jona-Lasinio model. We compute the masses of charged $\\rho$ mesons numerically as a function of the magnetic field for different values of temperature and chemical potential. The self-energy of the $\\rho$ meson contains the quark-loop contribution, i.e. the leading order contribution in $1/N_c$ expansion. The charged $\\rho$ meson mass decreases with the magnetic field and drops to zero at a critical magnetic field $eB_c$, which means that the charged vector meson condensation, i.e. the electromagnetic superconductor can be induced above the critical magnetic field. Surprisingly, it is found that the charged $\\rho$ condensation can even survive at high temperature and density. At zero temperature, the critical magnetic field just increases slightly with the chemical potential, which indicates that the charged $\\rho$ condensatio...

  7. Fast electronic resistance switching involving hidden charge density wave states

    Science.gov (United States)

    Vaskivskyi, I.; Mihailovic, I. A.; Brazovskii, S.; Gospodaric, J.; Mertelj, T.; Svetin, D.; Sutar, P.; Mihailovic, D.

    2016-05-01

    The functionality of computer memory elements is currently based on multi-stability, driven either by locally manipulating the density of electrons in transistors or by switching magnetic or ferroelectric order. Another possibility is switching between metallic and insulating phases by the motion of ions, but their speed is limited by slow nucleation and inhomogeneous percolative growth. Here we demonstrate fast resistance switching in a charge density wave system caused by pulsed current injection. As a charge pulse travels through the material, it converts a commensurately ordered polaronic Mott insulating state in 1T-TaS2 to a metastable electronic state with textured domain walls, accompanied with a conversion of polarons to band states, and concurrent rapid switching from an insulator to a metal. The large resistance change, high switching speed (30 ps) and ultralow energy per bit opens the way to new concepts in non-volatile memory devices manipulating all-electronic states.

  8. Geometric interpretation of density displacements and charge sensitivities

    Indian Academy of Sciences (India)

    Roman F Nalewajski

    2005-09-01

    The ``geometric” interpretation of the electronic density displacements in the Hilbert space is given and the associated projection-operator partitioning of the hardness and softness operators (kernels) is developed. The eigenvectors |á 〉 = \\{| 〉 \\} of the hardness operator define the complete (identity) projector $\\hat{P}$ = | 〉 〈 = 1 for general density displacements, including the charge-transfer (CT) component, while the eigenvectors | i 〉 = { | 〉} of the linear response operator determine the polarizational -projector, $\\hat{P}$ = | 〉 〈 |. Their difference thus defines the complementary CT-projector: $\\hat{P}$ = 1 - $\\hat{P}$. The complete vector space for density displacements can be also spanned by supplementing the -modes with the homogeneous CT-mode. These subspaces separate the integral (normalization) and local aspects of density shifts in molecular systems.

  9. Bone geometry, volumetric density, microarchitecture, and estimated bone strength assessed by HR-pQCT in Klinefelter syndrome

    DEFF Research Database (Denmark)

    Shanbhogue, Vikram V; Hansen, Stinus; Jørgensen, Niklas Rye;

    2014-01-01

    and height with 31 healthy subjects aged 35.9 ± 8.2 years. Dual-energy X-ray absorptiometry (DXA) and HR-pQCT were performed in all participants, and blood samples were analyzed for hormonal status and bone biomarkers in KS patients. Twenty-one KS patients were on long-term testosterone-replacement therapy.......03) at the tibia in KS patients. In addition, cortical thickness was significantly reduced, both at the radius and tibia (both p testosterone therapy. This study......Although the expected skeletal manifestations of testosterone deficiency in Klinefelter's syndrome (KS) are osteopenia and osteoporosis, the structural basis for this is unclear. The aim of this study was to assess bone geometry, volumetric bone mineral density (vBMD), microarchitecture...

  10. Magnetothermopower and Nernst effect in unconventional charge density waves

    Science.gov (United States)

    Dóra, Balázs; Maki, Kazumi; Ványolos, András; Virosztek, Attila

    2003-12-01

    Recently we have shown that the striking angular dependent magnetoresistance in the low-temperature phase (LTP) of α-(BEDT-TTF)2KHg(SCN)4 is consistently described in terms of unconventional charge density wave (UCDW). Here we investigate theoretically the thermoelectric power and the Nernst effect in unconventional density wave (UDW). The present results account consistently for the recent data of magnetothermopower in α-(BEDT-TTF)2KHg(SCN)4 obtained by Choi et al. [Phys. Rev. B 65, 205119 (2002)]. This confirms further our identification of LTP in this salt as UCDW. We propose also that the Nernst effect provides a clear signature of UDW.

  11. Scattered surface charge density: A tool for surface characterization

    KAUST Repository

    Naydenov, Borislav

    2011-11-28

    We demonstrate the use of nonlocal scanning tunneling spectroscopic measurements to characterize the local structure of adspecies in their states where they are significantly less perturbed by the probe, which is accomplished by mapping the amplitude and phase of the scattered surface charge density. As an example, we study single-H-atom adsorption on the n-type Si(100)-(4 × 2) surface, and demonstrate the existence of two different configurations that are distinguishable using the nonlocal approach and successfully corroborated by density functional theory. © 2011 American Physical Society.

  12. Pion transverse charge density from timelike form factor data

    Energy Technology Data Exchange (ETDEWEB)

    Gerald Miller, Mark Strikman, Christian Weiss

    2011-01-01

    The transverse charge density in the pion can be represented as a dispersion integral of the imaginary part of the pion form factor in the timelike region. This formulation incorporates information from e+e- annihilation experiments and allows one to reconstruct the transverse density much more accurately than from the spacelike pion form factor data alone. We calculate the transverse density using an empirical parametrization of the timelike pion form factor and estimate that it is determined to an accuracy of ~10% at a distance b ~ 0.1 fm, and significantly better at larger distances. The density is found to be close to that obtained from a zero-width rho meson pole over a wide range and shows a pronounced rise at small distances. The resulting two-dimensional image of the fast-moving pion can be interpreted in terms of its partonic structure in QCD. We argue that the singular behavior of the charge density at the center requires a substantial presence of pointlike configurations in the pion's partonic wave function, which can be probed in other high-momentum transfer processes.

  13. Charge, density and electron temperature in a molecular ultracold plasma

    CERN Document Server

    Rennick, C J; Ortega-Arroyo, J; Godin, P J; Grant, E R

    2009-01-01

    A Rydberg gas of NO entrained in a supersonic molecular beam releases electrons as it evolves to form an ultracold plasma. The size of this signal, compared with that extracted by the subsequent application of a pulsed electric field, determines the absolute magnitude of the plasma charge. This information, combined with the number density of ions, supports a simple thermochemical model that explains the evolution of the plasma to an ultracold electron temperature.

  14. Thermal Rounding of the Charge Density Wave Depinning Transition

    OpenAIRE

    Middleton, A. Alan

    1992-01-01

    The rounding of the charge density wave depinning transition by thermal noise is examined. Hops by localized modes over small barriers trigger ``avalanches'', resulting in a creep velocity much larger than that expected from comparing thermal energies with typical barriers. For a field equal to the $T=0$ depinning field, the creep velocity is predicted to have a {\\em power-law} dependence on the temperature $T$; numerical computations confirm this result. The predicted order of magnitude of t...

  15. Study of the Charge Density Control Method Including the Space Charge Effect in the Proton Synchrotron

    Science.gov (United States)

    Kato, Shinichi; Harada, Hiroyuki; Hotchi, Hideaki; Okabe, Kota; Yamamoto, Kazami; Kinsho, Michikazu

    For high intensity proton accelerators, one of the beam loss sources is the incoherent tune spread caused by the space charge force. In the 3 GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex, beams are injected sequentially and shifted slightly from the central orbit in order to increase the beam size intentionally and suppress the charge density and incoherent tune spread. This injection method has been adopted and suppressed the beam loss. However, simulations clarified that beams did not spread as much as expected because of the space charge effect in the high current case. As simulation results of the optimized beam shift pattern when the space charge effect is considered, it was obtained that the incoherent tune spread could be suppressed to an extent that has not been achieved previously.

  16. Realizing vector meson dominance with transverse charge densities

    CERN Document Server

    Miller, G A; Weiss, C

    2011-01-01

    The transverse charge density in a fast-moving nucleon is represented as a dispersion integral of the imaginary part of the Dirac form factor in the timelike region (spectral function). At a given transverse distance b the integration effectively extends over energies in a range sqrt{t} ~< 1/b, with exponential suppression of larger values. The transverse charge density at peripheral distances thus acts as a low-pass filter for the spectral function and allows one to select energy regions dominated by specific t-channel states, corresponding to definite exchange mechanisms in the spacelike form factor. We show that distances b ~ 0.5 - 1.5 fm in the isovector density are maximally sensitive to the rho meson region, with only a ~10% contribution from higher-mass states. Soft-pion exchange governed by chiral dynamics becomes relevant only at larger distances. In the isoscalar density higher-mass states beyond the omega are comparatively more important. The dispersion approach suggests that the positive transv...

  17. Effect of Spinal Degenerative Changes on Volumetric Bone Mineral Density of the Central Skeleton as Measured by Quantitative Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Guglielmi, G. [Hospital ' Casa Sollievo della Sofferenza' , San Giovanni Rotondo (Italy). Dept. of Radiology; Floriani, I.; Torri, V.; Li, J.; Kuijk, C. van; Genant, H.K.; Lang, T.F. [Scientific Inst. ' Mario Negri' , Milan (Italy). Biometry and Data Management Unit

    2005-05-01

    Purpose: To evaluate the impact of degenerative changes due to osteoarthritis (OA) at the spine on volumetric bone mineral density (BMD) as measured by volumetric quantitative computed tomography (vQCT). Material and Methods: Eighty-four elderly women (mean age 73 {+-}6 years), comprising 33 with vertebral fractures assessed by radiographs and 51 without vertebral fractures, were studied. Trabecular, cortical, and integral BMD were examined at the spine and hip using a helical CT scanner and were compared to dual X-ray absorptiometry (DXA) measurements at the same sites. OA changes visible on the radiographs were categorized into two grades according to severity. Differences in BMD measures obtained in the two groups of patients defined by OA grade using the described radiologic methods were compared using analysis of variance. Standardized difference (effect sizes) was also compared between radiologic methods. Results: Spinal trabecular BMD did not differ significantly between OA grade 0 and OA grade. Spinal cortical and integral BMD measures showed statistically significant differences, as did the lumbar spine DXA BMD measurement (13%, P{approx_equal}0.02). The QCT measurements at the hip were also higher in OA subjects. Femoral trabecular BMD was 3-15% higher in OA grade subjects than in OA grade 0 subjects. The cortical BMD measures in the CT{sub T}OT{sub F}EM and CT{sub T}ROCH ROI's were also higher in the OA subjects. The integral QCT BMD measures in the hip showed difference between grades OA and 0. The DXA measurements in the neck and trochanter ROI's showed smaller differences (9 and 1%, respectively). There were no statistically significant differences in bone size. Conclusion: There is no evidence supporting that trabecular BMD measurements by QCT are influenced by OA. Instead, degenerative changes have an effect on both cortical and integral QCT, and on DXA at the lumbar spine and the hip. For subjects with established OA, assessment of BMD by

  18. Charge Order Induced in an Orbital Density-Wave State

    Science.gov (United States)

    Singh, Dheeraj Kumar; Takimoto, Tetsuya

    2016-04-01

    Motivated by recent angle resolved photoemission measurements [D. V. Evtushinsky et al., Phys. Rev. Lett. 105, 147201 (2010)] and evidence of the density-wave state for the charge and orbital ordering [J. García et al., Phys. Rev. Lett. 109, 107202 (2012)] in La0.5Sr1.5MnO4, the issue of charge and orbital ordering in a two-orbital tight-binding model for layered manganite near half doping is revisited. We find that the charge order with the ordering wavevector 2{Q} = (π ,π ) is induced by the orbital order of d-/d+-type having B1g representation with a different ordering wavevector Q, where the orbital order as the primary order results from the strong Fermi-surface nesting. It is shown that the induced charge order parameter develops according to TCO - T by decreasing the temperature below the orbital ordering temperature TCO, in addition to the usual mean-field behavior of the orbital order parameter. Moreover, the same orbital order is found to stabilize the CE-type spin arrangement observed experimentally below TCE < TCO.

  19. Charge-density waves physics revealed by photoconduction

    Energy Technology Data Exchange (ETDEWEB)

    Zaitsev-Zotov, S.V., E-mail: serzz@cplire.ru [Kotel' nikov Institute of Radio-engineering and Electronics of the RAS, 125009 Moscow (Russian Federation); Moscow Institute of Physics and Technology, 141700 Dolgoprudny (Russian Federation); Nasretdinova, V.F.; Minakova, V.E. [Kotel' nikov Institute of Radio-engineering and Electronics of the RAS, 125009 Moscow (Russian Federation)

    2015-03-01

    The results of photoconduction study of the Peierls conductors are reviewed. The studied materials are quasi-one-dimensional conductors with the charge-density wave: K{sub 0.3}MoO{sub 3}, both monoclinic and orthorhombic TaS{sub 3} and also a semiconducting phase of NbS{sub 3} (phase I). Experimental methods, relaxation times, effects of illumination on linear and nonlinear charge transport, the electric-field effect on photoconduction and results of the spectral studies are described. We demonstrate, in particular, that a simple model of modulated energy gap slightly smoothed by fluctuations fits the available spectral data fairly well. The level of the fluctuations is surprisingly small and does not exceed a few percent of the optical energy gap value.

  20. Surface modification for polystyrene colloidal particles with controlled charge densities.

    Science.gov (United States)

    Lee, Jongman; Kwon, Oh-Sun; Shin, Kwanwoo; Song, Ju-Myung; Kim, Joon-Seop; Seo, Young-Soo; Tael, Giyoong; Jon, Sangyong

    2007-11-01

    A significant amount of polystyrene sulfonated acid (PSSA) and poly(styrene-ran-acrylic acid) (PSAA) random copolymer can be adsorbed by dispersion of PS particles via a swelling-quenching process. A THF-water mixed solvent was used in the swelling process and a large amount of pure water was used, to give a low concentration of THF% in quenching process. Our results showed that functional PSSA groups were randomly and tightly adsorbed to the PS particles. When the mol.% of charged segments was increased, the progressive adsorption of PSSA chains to the PS particles leads to an increase in the electrophoretic mobility and zeta-potential of aqueous dispersions. Thus, we were able to obtain well-distributed surface charge density on the PS particles.

  1. Shells of charge: a density functional theory for charged hard spheres.

    Science.gov (United States)

    Roth, Roland; Gillespie, Dirk

    2016-06-22

    A functional for the electrostatic excess free-energy for charged, hard sphere fluids is proposed. The functional is derived from two complementary, but equivalent, interpretations of the mean spherical approximation (MSA). The first combines fundamental measure theory (FMT) from hard-core interactions with the idea that MSA can be interpreted in terms of the interaction spherical shells of charge. This formulation gives the free-energy density as a function of weighted densities. When all the ions have the same size, the functional adopts an FMT-like form. The second in effect 'functionalizes' the derivation of MSA; that is, it generalizes the MSA as a functional-based version of MSA (fMSA). This formulation defines the free-energy density as a function of a position-dependent MSA screening parameter and the weighted densities of the FMT approach. This FMT/fMSA functional is shown to give accurate density profiles, as compared to Monte Carlo simulations, under a wide range of ion concentrations, size asymmetries, and valences.

  2. Shells of charge: a density functional theory for charged hard spheres

    Science.gov (United States)

    Roth, Roland; Gillespie, Dirk

    2016-06-01

    A functional for the electrostatic excess free-energy for charged, hard sphere fluids is proposed. The functional is derived from two complementary, but equivalent, interpretations of the mean spherical approximation (MSA). The first combines fundamental measure theory (FMT) from hard-core interactions with the idea that MSA can be interpreted in terms of the interaction spherical shells of charge. This formulation gives the free-energy density as a function of weighted densities. When all the ions have the same size, the functional adopts an FMT-like form. The second in effect ‘functionalizes’ the derivation of MSA; that is, it generalizes the MSA as a functional-based version of MSA (fMSA). This formulation defines the free-energy density as a function of a position-dependent MSA screening parameter and the weighted densities of the FMT approach. This FMT/fMSA functional is shown to give accurate density profiles, as compared to Monte Carlo simulations, under a wide range of ion concentrations, size asymmetries, and valences.

  3. Photoemission spectra of charge density wave states in cuprates

    Science.gov (United States)

    Tu, Wei-Lin; Chen, Peng-Jen; Lee, Ting-Kuo

    Angle-resolved photoemission spectroscopy(ARPES) experiments have reported many exotic properties of cuprates, such as Fermi arc at normal state, two gaps at superconducting state and particle-hole asymmetry at the antinodal direction. On the other hand, a number of inhomogeneous states or so-called charge density waves(CDW) states have also been discovered in cuprates by many experimental groups. The relation between these CDW states and ARPES spectra is unclear. With the help of Gutzwiller projected mean-field theory, we can reproduce the quasiparticle spectra in momentum space. The spectra show strong correspondence to the experimental data with afore-mentioned exotic features in it.

  4. Flexible Aqueous Lithium-Ion Battery with High Safety and Large Volumetric Energy Density.

    Science.gov (United States)

    Dong, Xiaoli; Chen, Long; Su, Xiuli; Wang, Yonggang; Xia, Yongyao

    2016-06-20

    A flexible and wearable aqueous lithium-ion battery is introduced based on spinel Li1.1 Mn2 O4 cathode and a carbon-coated NASICON-type LiTi2 (PO4 )3 anode (NASICON=sodium-ion super ionic conductor). Energy densities of 63 Wh kg(-1) or 124 mWh cm(-3) and power densities of 3 275 W kg(-1) or 11.1 W cm(-3) can be obtained, which are seven times larger than the largest reported till now. The full cell can keep its capacity without significant loss under different bending states, which shows excellent flexibility. Furthermore, two such flexible cells in series with an operation voltage of 4 V can be compatible with current nonaqueous Li-ion batteries. Therefore, such a flexible cell can potentially be put into practical applications for wearable electronics. In addition, a self-chargeable unit is realized by integrating a single flexible aqueous Li-ion battery with a commercial flexible solar cell, which may facilitate the long-time outdoor operation of flexible and wearable electronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Charge carrier density in Li-intercalated graphene

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-05-01

    The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young\\'s modulus suggests that Li-intercalation increases the intrinsic stiffness. For decreasing Li-C interaction, the Dirac point shifts to the Fermi level and the associated band splitting vanishes. For Li-intercalated bilayer graphene on SiC(0 0 0 1) the splitting at the Dirac point is tiny. It is also very small at the two Dirac points of Li-intercalated trilayer graphene on SiC(0 0 0 1). For all the systems under study, a large enhancement of the charge carrier density is achieved by Li intercalation. © 2012 Elsevier B.V. All rights reserved.

  6. Photoinduced Enhancement of the Charge Density Wave Amplitude

    Science.gov (United States)

    Singer, A.; Patel, S. K. K.; Kukreja, R.; Uhlíř, V.; Wingert, J.; Festersen, S.; Zhu, D.; Glownia, J. M.; Lemke, H. T.; Nelson, S.; Kozina, M.; Rossnagel, K.; Bauer, M.; Murphy, B. M.; Magnussen, O. M.; Fullerton, E. E.; Shpyrko, O. G.

    2016-07-01

    Symmetry breaking and the emergence of order is one of the most fascinating phenomena in condensed matter physics. It leads to a plethora of intriguing ground states found in antiferromagnets, Mott insulators, superconductors, and density-wave systems. Exploiting states of matter far from equilibrium can provide even more striking routes to symmetry-lowered, ordered states. Here, we demonstrate for the case of elemental chromium that moderate ultrafast photoexcitation can transiently enhance the charge-density-wave (CDW) amplitude by up to 30% above its equilibrium value, while strong excitations lead to an oscillating, large-amplitude CDW state that persists above the equilibrium transition temperature. Both effects result from dynamic electron-phonon interactions, providing an efficient mechanism to selectively transform a broad excitation of the electronic order into a well-defined, long-lived coherent lattice vibration. This mechanism may be exploited to transiently enhance order parameters in other systems with coupled degrees of freedom.

  7. Directly Grown Nanostructured Electrodes for High Volumetric Energy Density Binder-Free Hybrid Supercapacitors: A Case Study of CNTs//Li4Ti5O12

    Science.gov (United States)

    Zuo, Wenhua; Wang, Chong; Li, Yuanyuan; Liu, Jinping

    2015-01-01

    Hybrid supercapacitor (HSC), which typically consists of a Li-ion battery electrode and an electric double-layer supercapacitor electrode, has been extensively investigated for large-scale applications such as hybrid electric vehicles, etc. Its application potential for thin-film downsized energy storage systems that always prefer high volumetric energy/power densities, however, has not yet been explored. Herein, as a case study, we develop an entirely binder-free HSC by using multiwalled carbon nanotube (MWCNT) network film as the cathode and Li4Ti5O12 (LTO) nanowire array as the anode and study the volumetric energy storage capability. Both the electrode materials are grown directly on carbon cloth current collector, ensuring robust mechanical/electrical contacts and flexibility. Our 3 V HSC device exhibits maximum volumetric energy density of ~4.38 mWh cm-3, much superior to those of previous supercapacitors based on thin-film electrodes fabricated directly on carbon cloth and even comparable to the commercial thin-film lithium battery. It also has volumetric power densities comparable to that of the commercial 5.5 V/100 mF supercapacitor (can be operated within 3 s) and has excellent cycling stability (~92% retention after 3000 cycles). The concept of utilizing binder-free electrodes to construct HSC for thin-film energy storage may be readily extended to other HSC electrode systems.

  8. Classification of charge density waves based on their nature.

    Science.gov (United States)

    Zhu, Xuetao; Cao, Yanwei; Zhang, Jiandi; Plummer, E W; Guo, Jiandong

    2015-02-24

    The concept of a charge density wave (CDW) permeates much of condensed matter physics and chemistry. CDWs have their origin rooted in the instability of a one-dimensional system described by Peierls. The extension of this concept to reduced dimensional systems has led to the concept of Fermi surface nesting (FSN), which dictates the wave vector [Formula: see text] of the CDW and the corresponding lattice distortion. The idea is that segments of the Fermi contours are connected by [Formula: see text], resulting in the effective screening of phonons inducing Kohn anomalies in their dispersion at [Formula: see text], driving a lattice restructuring at low temperatures. There is growing theoretical and experimental evidence that this picture fails in many real systems and in fact it is the momentum dependence of the electron-phonon coupling (EPC) matrix element that determines the characteristic of the CDW phase. Based on the published results for the prototypical CDW system 2H-NbSe2, we show how well the [Formula: see text]-dependent EPC matrix element, but not the FSN, can describe the origin of the CDW. We further demonstrate a procedure of combing electronic band and phonon measurements to extract the EPC matrix element, allowing the electronic states involved in the EPC to be identified. Thus, we show that a large EPC does not necessarily induce the CDW phase, with Bi2Sr2CaCu2O8+δ as the example, and the charge-ordered phenomena observed in various cuprates are not driven by FSN or EPC. To experimentally resolve the microscopic picture of EPC will lead to a fundamental change in the way we think about, write about, and classify charge density waves.

  9. Comparison of Visual Assessment of Breast Density in BI-RADS 4th and 5th Editions With Automated Volumetric Measurement.

    Science.gov (United States)

    Youk, Ji Hyun; Kim, So Jung; Son, Eun Ju; Gweon, Hye Mi; Kim, Jeong-Ah

    2017-09-01

    The purpose of this study was to compare visual assessments of mammographic breast density by radiologists using BI-RADS 4th and 5th editions in correlation with automated volumetric breast density measurements. A total of 337 consecutive full-field digital mammographic examinations with standard views were retrospectively assessed by two radiologists for mammographic breast density according to BI-RADS 4th and 5th editions. Fully automated measurement of the volume of fibroglandular tissue and total breast and percentage breast density was performed with a commercially available software program. Interobserver and intraobserver agreement was assessed with kappa statistics. The distributions of breast density categories for both editions of BI-RADS were compared and correlated with volumetric data. Interobserver agreement on breast density category was moderate to substantial (κ = 0.58-0.63) with use of BI-RADS 4th edition and substantial (κ = 0.63-0.66) with use of the 5th edition but without significant difference between the two editions. For intraobserver agreement between the two editions, the distributions of density category were significantly different (p density data, including percentage breast density, were significantly different among density categories (p density assessment had good correlation with visual assessment for both editions of BI-RADS.

  10. Comparison of the relationship between bone marrow adipose tissue and volumetric bone mineral density in children and adults.

    Science.gov (United States)

    Shen, Wei; Velasquez, Gilbert; Chen, Jun; Jin, Ye; Heymsfield, Steven B; Gallagher, Dympna; Pi-Sunyer, F Xavier

    2014-01-01

    Several large-scale studies have reported the presence of an inverse relationship between bone mineral density (BMD) and bone marrow adipose tissue (BMAT) in adults. We aim to determine if there is an inverse relationship between pelvic volumetric BMD (vBMD) and pelvic BMAT in children and to compare this relationship in children and adults. Pelvic BMAT and bone volume (BV) was evaluated in 181 healthy children (5-17yr) and 495 healthy adults (≥18yr) with whole-body magnetic resonance imaging (MRI). Pelvic vBMD was calculated using whole-body dual-energy X-ray absorptiometry to measure pelvic bone mineral content and MRI-measured BV. An inverse correlation was found between pelvic BMAT and pelvic vBMD in both children (r=-0.374, pBMAT as the independent variable, being a child or adult neither significantly contribute to the pelvic BMD (p=0.995) nor did its interaction with pelvic BMAT (p=0.415). The inverse relationship observed between pelvic vBMD and pelvic BMAT in children extends previous findings that found the inverse relationship to exist in adults and provides further support for a reciprocal relationship between adipocytes and osteoblasts.

  11. Breathing charge density waves in intrinsic Josephson junctions

    Science.gov (United States)

    Shukrinov, Yu. M.; Abdelhafiz, H.

    2014-01-01

    We demonstrate the creation of a charge density wave (CDW) along a stack of coupled Josephson junctions (JJs) in layered superconductors. Electric charge in each superconducting layer oscillates around some average value, forming a breathing CDW. We show the transformation of a longitudinal plasma wave to CDW in the state corresponding to the outermost branch. Transition between different types of CDW's related to the inner branches of IV characteristic is demonstrated. The effect of the external electromagnetic radiation on the states corresponding to the inner branches differs crucially from the case of the single JJ. The Shapiro steps in the IV characteristics of the junctions in the stack do not correspond directly to the frequency of radiation ω. The system of JJs behaves like a single whole system: the Shapiro steps or their harmonics in the total IV characteristics appear at voltage , where V l is the voltage in the lth junction, N R is the number of JJs in the rotating state, and m and n are integers.

  12. Areal and Volumetric Bone Mineral Density and Geometry at Two Levels of Protein Intake During Caloric Restriction: A Randomized, Controlled Trial

    OpenAIRE

    Sukumar, Deeptha; Ambia-Sobhan, Hasina; Zurfluh, Robert; Schlussel, Yvette; Stahl, Theodore J; Gordon, Chris L; SHAPSES, SUE A.

    2010-01-01

    Weight reduction induces bone loss by several factors, and the effect of higher protein (HP) intake during caloric restriction on bone mineral density (BMD) is not known. Previous study designs examining the longer-term effects of HP diets have not controlled for total calcium intake between groups and have not examined the relationship between bone and endocrine changes. In this randomized, controlled study, we examined how BMD (areal and volumetric), turnover markers, and hormones [insulin-...

  13. Bone geometry, volumetric density, microarchitecture, and estimated bone strength assessed by HR-pQCT in Klinefelter syndrome.

    Science.gov (United States)

    Shanbhogue, Vikram V; Hansen, Stinus; Jørgensen, Niklas Rye; Brixen, Kim; Gravholt, Claus H

    2014-11-01

    Although the expected skeletal manifestations of testosterone deficiency in Klinefelter's syndrome (KS) are osteopenia and osteoporosis, the structural basis for this is unclear. The aim of this study was to assess bone geometry, volumetric bone mineral density (vBMD), microarchitecture, and estimated bone strength using high-resolution peripheral quantitative computed tomography (HR-pQCT) in patients with KS. Thirty-one patients with KS confirmed by lymphocyte chromosome karyotyping aged 35.8 ± 8.2 years were recruited consecutively from a KS outpatient clinic and matched with respect to age and height with 31 healthy subjects aged 35.9 ± 8.2 years. Dual-energy X-ray absorptiometry (DXA) and HR-pQCT were performed in all participants, and blood samples were analyzed for hormonal status and bone biomarkers in KS patients. Twenty-one KS patients were on long-term testosterone-replacement therapy. In weight-adjusted models, HR-pQCT revealed a significantly lower cortical area (p < 0.01), total and trabecular vBMD (p = 0.02 and p = 0.04), trabecular bone volume fraction (p = 0.04), trabecular number (p = 0.05), and estimates of bone strength, whereas trabecular spacing was higher (p = 0.03) at the tibia in KS patients. In addition, cortical thickness was significantly reduced, both at the radius and tibia (both p < 0.01). There were no significant differences in indices of bone structure, estimated bone strength, or bone biomarkers in KS patients with and without testosterone therapy. This study showed that KS patients had lower total vBMD and a compromised trabecular compartment with a reduced trabecular density and bone volume fraction at the tibia. The compromised trabecular network integrity attributable to a lower trabecular number with relative preservation of trabecular thickness is similar to the picture found in women with aging. KS patients also displayed a reduced cortical area and thickness at the tibia, which in

  14. Plane density of induced vacuum charge in a supercritical Coulomb potential

    CERN Document Server

    Khalilov, V R

    2016-01-01

    An expression for the density of a planar induced vacuum charge is obtained in a strong Coulomb potential in coordinate space. Treatment is based on a self-adjoint extension approach for constructing of the Green's function of a charged fermion in this potential. Induced vacuum charge density is calculated and analyzed at the subcritical and supercritical Coulomb potentials for massless and massive fermions. The behavior of the obtained vacuum charge density is investigated at long and short distances from the Coulomb center. The induced vacuum charge has a screening sign. Screening of a Coulomb impurity in graphene is briefly discussed. We calculate the real vacuum polarization charge density that acquires the quantum electrodynamics vacuum in the supercritical Coulomb potential due to the so-called real vacuum polarization. It is shown that the vacuum charge densities essentially differ in massive and massless cases. We expect that our results can, as a matter of principle, be tested in graphene with a supe...

  15. Dynamical charge density waves rule the phase diagram of cuprates

    Science.gov (United States)

    Caprara, S.; Di Castro, C.; Seibold, G.; Grilli, M.

    2017-06-01

    In the last few years, charge density waves (CDWs) have been ubiquitously observed in high-temperature superconducting cuprates and are now the most investigated among the competing orders in the still hot debate on these systems. A wealth of new experimental data raises several fundamental issues that challenge the various theoretical proposals. We here relate our mean-field instability line TCDW0 of a strongly correlated Fermi liquid to the pseudogap T*(p ) line, marking in this way the onset of CDW-fluctuations. These fluctuations reduce strongly the mean-field critical line. Controlling this reduction via an infrared frequency cutoff related to the characteristic time of the probes, we account for the complex experimental temperature versus doping phase diagram. We provide a coherent scenario explaining why different CDW onset curves are observed by different experimental probes and seem to extrapolate at zero temperature into seemingly different quantum critical points (QCPs) in the intermediate and overdoped region. The nearly singular anisotropic scattering mediated by these fluctuations also accounts for the rapid changes of the Hall number seen in experiments and provides the first necessary step for a possible Fermi surface reconstruction fully establishing at lower doping. Finally, we show that phase fluctuations of the CDWs, which are enhanced in the presence of strong correlations near the Mott insulating phase, naturally account for the disappearance of the CDWs at low doping with yet another QCP as seen by the experiments.

  16. Experimental surface charge density of the Si (100)-2x1H surface

    DEFF Research Database (Denmark)

    Ciston, J.; Marks, L.D.; Feidenhans'l, R.;

    2006-01-01

    We report a three-dimensional charge density refinement from x-ray diffraction intensities of the Si (100) 2x1H surface. By paying careful attention to parameterizing the bulk Si bonding, we are able to locate the hydrogen atoms at the surface, which could not be done previously. In addition, we...... are able to partially refine the local charge density at the surface. We find experimentally an increased, slightly localized bond density of approximately 0.31 electrons between each Si atom pair at the surface. Both the atomic positions and the charge density are in remarkably good agreement with density...

  17. Experimental surface charge density of the Si (100)-2x1H surface

    DEFF Research Database (Denmark)

    Ciston, J.; Marks, L.D.; Feidenhans'l, R.

    2006-01-01

    We report a three-dimensional charge density refinement from x-ray diffraction intensities of the Si (100) 2x1H surface. By paying careful attention to parameterizing the bulk Si bonding, we are able to locate the hydrogen atoms at the surface, which could not be done previously. In addition, we...... are able to partially refine the local charge density at the surface. We find experimentally an increased, slightly localized bond density of approximately 0.31 electrons between each Si atom pair at the surface. Both the atomic positions and the charge density are in remarkably good agreement with density...

  18. Rendering high charge density of states in ionic liquid-gated MoS 2 transistors

    NARCIS (Netherlands)

    Lee, Y.; Lee, J.; Kim, S.; Park, H.S.

    2014-01-01

    We investigated high charge density of states (DOS) in the bandgap of MoS2 nanosheets with variable temperature measurements on ionic liquid-gated MoS2 transistors. The thermally activated charge transport indicates that the electrical current in the two-dimensional MoS 2 nanosheets under high charg

  19. Solution of Equations of Internal Ballistics for the Composite Charge Using Lagrange Density Approximation

    Directory of Open Access Journals (Sweden)

    D. K. Narvilkar

    1979-07-01

    Full Text Available In the present paper, the equations of internal ballistics of composite charge consisting of N component charge with quadratic form are solved. Largange density approximation and hydrodynamic flow behaviour, have been assumed and the solutions are obtained for the composite charge for these assumptions.

  20. Far-Infrared Study of the Charge Density Wave in Tetrathiofulvalene Tetracyanoquinodimethane (TTF-TCNQ)

    DEFF Research Database (Denmark)

    Tanner, D. B.; Cummings, K. D.; Jacobsen, Claus Schelde

    1981-01-01

    Detailed far-infrared measurements at temperatures from 25 to 300 K provide strong support for a charge-density-wave mechanism for the dc conductivity and microwave dielectric constant of tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ). At low temperatures the charge-density wave is pinned...

  1. Charge Density Quantification of Polyelectrolyte Polysaccharides by Conductometric Titration: An Analytical Chemistry Experiment

    Science.gov (United States)

    Farris, Stefano; Mora, Luigi; Capretti, Giorgio; Piergiovanni, Luciano

    2012-01-01

    An easy analytical method for determination of the charge density of polyelectrolytes, including polysaccharides and other biopolymers, is presented. The basic principles of conductometric titration, which is used in the pulp and paper industry as well as in colloid and interface science, were adapted to quantify the charge densities of a…

  2. Empirical transverse charge densities in the nucleon and the nucleon-to-Delta transition

    Energy Technology Data Exchange (ETDEWEB)

    Carl Carlson; Marc Vanderhaeghen

    2008-01-01

    Using only the current empirical information on the nucleon electromagnetic form factors we map out the transverse charge density in proton and neutron as viewed from a light front moving towards a transversely polarized nucleon. These charge densities are characterized by a dipole pattern, in addition to the monopole field corresponding with the unpolarized density. Furthermore, we use the latest empirical information on the $N \\to \\Delta$ transition form factors to map out the transition charge density which induces the $N \\to \\Delta$ excitation. This transition charge density in a transversely polarized $N$ and $\\Delta$ contains both monopole, dipole and quadrupole patterns, the latter corresponding with a deformation of the hadron's charge distribution.

  3. Topics in the Dynamics of Charge-Density

    Science.gov (United States)

    Ramakrishna, Sathyanarayan (Satish).

    This dissertation is an investigation into some interesting transport properties of charge-density-waves (CDWs). The field of CDW dynamics is an arena for the battle between mathematical analysis and random disorder. It is a very difficult physical situation to analyze. The theoretical study of CDW dynamics dates to the prescient suggestion of John Bardeen (in the 70s) that the nonlinear I-V characteristic of the quasi one-dimensional material TTF-TCNQ was a consequence of collective transport of condensate resulting from a Peierls instability. This instability, described first by Peierls, is studied in Chapter 1. Once the underlying physics of the instability was understood, the effects of coupling the CDW to impurities and to electric and magnetic fields were studied. The most striking effect of impurities is to produce CDW pinning, so that collective-mode transport ceases to occur if the applied electric field is smaller than a threshold field. Intensive research led to the Fukuyama-Lee-Rice model of CDW pinning. Experiments in the field are complicated by the difficulty in preparing well characterized samples of the relevant materials, among which are the trichalco-genides NbSe_3, TaS_3, the dichalcogenides (TaSe_4)_2I, TaS_2, NbSe_2 and blue bronze K_{0.3}MoO _3. Over the last decade, growth techniques have been perfected and intensive comparison between the various theoretical models and experiment is feasible. An outline of the dissertation is as follows. First, we review the theoretical ideas that underlie the subject. Then we discuss each new piece of work separately. First, this thesis presents one important theoretical approach to the study of CDW dynamics. The approach builds upon previous work on the microscopic theory of superconductors and results in a new formulation of the problem that seems likely to lend itself to non-perturbative approaches. The perturbative approach cannot provide answers to the question of what happens near the depinning

  4. Deformations of charge-density wave crystals under electric field

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovskii, V.Ya. [Kotel' nikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11, 125009 Moscow (Russian Federation)], E-mail: pok@cplire.ru; Zybtsev, S.G.; Loginov, V.B. [Kotel' nikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11, 125009 Moscow (Russian Federation); Timofeev, V.N. [Baikov Institute of Metallurgy of RAS, Leninsky prosp. 49, 119991 Moscow (Russian Federation); Kolesov, D.V.; Yaminsky, I.V. [Advanced Technologies Center, Department of Physics, Moscow State University, Leninskie Gori, 119991 Moscow (Russian Federation); Gorlova, I.G. [Kotel' nikov Institute of Radioengineering and Electronics of RAS, Mokhovaya 11, 125009 Moscow (Russian Federation)

    2009-03-01

    We report the effects of electric field induced deformations of quasi one-dimensional conductors with charge-density wave (CDW). The most pronounced sort of deformation is torsional strain (TS). The TS is found to comprise two contributions. The features of the 1st-the larger one-are threshold hysteretic dependence on electric field and high relaxation time {tau}: For o-TaS{sub 3}{tau}{approx}10{sup -2} s at T=80 K and falls as exp(900 K/T) with increasing T. The 2nd contribution is linear in electric field and does not drop with frequency increase. The amplitude of this contribution falls abruptly with T approaching the Peierls transition temperature T{sub P} from below. Similar features of TS are demonstrated for other CDW compounds: (TaSe{sub 4}){sub 2}I, K{sub 0.3}MoO{sub 3} and NbS{sub 3} type II, for which T{sub P}{approx}360 K. We attribute the 1st and the 2nd contributions to large (hysteretic) and small (near-equilibrium) CDW deformations, respectively, likely-shear at the surface. The TS is observed also above T{sub P}: For TaS{sub 3} and (TaSe{sub 4}){sub 2}I typical torsional amplitude is 10{sup -1} deg./V in the resonance regimes, corresponding to the piezomodulus {approx}10{sup -9} m/V. A separate study of TS was performed at room temperature with AFM technique. Apart from this ('intrinsic') effect, we observe electrostatic contribution to the TS. In contrast to the intrinsic response, the electrostatic one is proportional to the potential either over the sample, or over an additional electrode ('gate') placed nearby, but not to the difference of potentials between the sample ends. It is typically 2 orders of magnitude less. The intrinsic TS reveals a new electromechanical effect at room temperature, presumably associated with the excitations of the pinned mode of the CDW fluctuations. Its observation opens prospects for application of quasi one-dimensional conductors as micro- and nano-actuators. Basing on the electrostatic

  5. Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities

    Science.gov (United States)

    Harrison, Neil; Singleton, John; Migliori, Albert

    2008-08-05

    A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

  6. From super-charged nuclei to massive nuclear density cores

    CERN Document Server

    Popov, Vladimir

    2010-01-01

    Due to $e^+e^-$-pair production in the field of supercritical $(Z \\gg Z_{cr}\\approx 170 $) nucleus an electron shell, created out of the vacuum, is formed. The distribution of the vacuum charge in this shell has been determined for super-charged nuclei $Ze^3 \\ga 1$ within the framework of the Thomas-Fermi equation generalized to the relativistic case. For $Ze^3 \\gg 1$ the electron shell penetrates inside the nucleus and almost completely screens its charge. Inside such nucleus the potential takes a constant value equal to $V_0=-(3\\pi^2 n_p)^{1/3} \\sim -2m_{\\pi}c^2$, and super-charged nucleus represents an electrically neutral plasma consisting of $e,p$ and $n$. Near the edge of the nucleus a transition layer exists with a width $\\lambda \\approx \\alpha^{-1/2} \\hbar/m_{\\pi} c\\sim 15$ fm, which is independent of $Z~~ (\\hbar/m_{\\pi} c \\ll \\lambda \\ll \\hbar/m_e c)$. The electric field and surface charge are concentrated in this layer. These results, obtained earlier for hypothetical superheavy nuclei with $Z \\sim ...

  7. Bone lead (Pb) content at the tibia is associated with thinner distal tibia cortices and lower volumetric bone density in postmenopausal women.

    Science.gov (United States)

    Wong, Andy K O; Beattie, Karen A; Bhargava, Aakash; Cheung, Marco; Webber, Colin E; Chettle, David R; Papaioannou, Alexandra; Adachi, Jonathan D

    2015-10-01

    Conflicting evidence suggests that bone lead or blood lead may reduce areal bone mineral density (BMD). Little is known about how lead at either compartment affects bone structure. This study examined postmenopausal women (N=38, mean age 76 ± 8, body mass index (BMI): 26.74 ± 4.26 kg/m(2)) within the Hamilton cohort of the Canadian Multicentre Osteoporosis Study (CaMos), measuring bone lead at 66% of the non-dominant leg and at the calcaneus using (109)Cadmium X-ray fluorescence. Volumetric BMD and structural parameters were obtained from peripheral quantitative computed tomography images (200 μm in-plane resolution, 2.3 ± 0.5mm slice thickness) of the same 66% site and of the distal 4% site of the tibia length. Blood lead was measured using atomic absorption spectrometry and blood-to-bone lead partition coefficients (PBB, log ratio) were computed. Multivariable linear regression examined each of bone lead at the 66% tibia, calcaneus, blood lead and PBB as related to each of volumetric BMD and structural parameters, adjusting for age and BMI, diabetes or antiresorptive therapy. Regression coefficients were reported along with 95% confidence intervals. Higher amounts of bone lead at the tibia were associated with thinner distal tibia cortices (-0.972 (-1.882, -0.061) per 100 μg Pb/g of bone mineral) and integral volumetric BMD (-3.05 (-6.05, -0.05) per μg Pb/g of bone mineral). A higher PBB was associated with larger trabecular separation (0.115 (0.053, 0.178)), lower trabecular volumetric BMD (-26.83 (-50.37, -3.29)) and trabecular number (-0.08 (-0.14, -0.02)), per 100 μg Pb/g of bone mineral after adjusting for age and BMI, and remained significant while accounting for diabetes or use of antiresorptives. Total lead exposure activities related to bone lead at the calcaneus (8.29 (0.11, 16.48)) and remained significant after age and antiresorptives-adjustment. Lead accumulated in bone can have a mild insult on bone structure; but greater partitioning of lead

  8. Modulated spin and charge densities in cuprate superconductors

    OpenAIRE

    Tranquada, J. M.

    1997-01-01

    Neutron scattering experiments have played a crucial role in characterizing the spin and charge correlations in copper-oxide superconductors. While the data are often interpreted with respect to specific theories of the cuprates, an attempt is made here to distinguish those facts that can be extracted empirically, and the connections that can be made with minimal assumptions.

  9. Are adult patients with Laron syndrome osteopenic? A comparison between dual-energy X-ray absorptiometry and volumetric bone densities.

    Science.gov (United States)

    Benbassat, Carlos A; Eshed, Varda; Kamjin, Moshe; Laron, Zvi

    2003-10-01

    Severe short stature resulting from a deficiency in IGF-I is a prominent feature of Laron syndrome (LS). Although low bone mineral density (BMD) has been noted in LS patients examined by dual energy x-ray absorptiometry (DEXA), this technique does not take volume into account and may therefore underestimate the true bone density in patients with small bones. The aim of the present study was to evaluate the BMD yielded by DEXA in our LS patients using estimated volumetric values. Volumetric density was calculated with the following formulas: bone mineral apparent density (BMAD) = bone mineral content (BMC)/(area)(3/2) for the lumbar spine and BMAD = BMC/area(2) for the femoral neck. The study sample included 12 patients (mean age, 43.9 yr; mean height, 123.7 cm). Findings were compared with 10 osteopenic subjects without developmental abnormalities (mean age, 56 yr; mean height, 164.8 cm) and 10 healthy control subjects matched for sex and age to the LS patients (mean height, 165.5 cm). BMAD in the LS group was 0.201 +/- 0.02 g/cm(3) at the lumbar spine and 0.201 +/- 0.04 g/cm(3) at the femoral neck; corresponding values for the osteopenic group were 0.130 +/- 0.01 and 0.140 +/- 0.01 g/cm(3), and for the controls, 0.178 +/- 0.03 and 0.192 +/- 0.02 g/cm(3). Although areal BMD was significantly lower in the LS and osteopenic subjects compared with controls (P < 0.02) at both the lumbar spine and femoral neck, BMAD was low (P < 0.01) in the osteopenic group only. In conclusion, DEXA does not seem to be a reliable measure of osteoporosis in patients with LS.

  10. Influence of Electric Charge and Modified Gravity on Density Irregularities

    CERN Document Server

    Bhatti, M Zaeem Ul Haq

    2016-01-01

    This work aims to identify some inhomogeneity factors for plane symmetric topology with anisotropic and dissipative fluid under the effects of both electromagnetic field as well as Palatini $f(R)$ gravity. We construct the modified field equations, kinematical quantities and mass function to continue our analysis. We have explored the dynamical quantities, conservation equations and modified Ellis equations with the help of a viable $f(R)$ model. Some particular cases are discussed with and without dissipation to investigate the corresponding inhomogeneity factors. For non-radiating scenario, we examine such factors with dust, isotropic and anisotropic matter in the presence of charge. For dissipative fluid, we investigate the inhomogeneity factor with charged dust cloud. We conclude that electromagnetic field increases the inhomogeneity in matter while the extra curvature terms make the system more homogeneous with the evolution of time.

  11. Influence of electric charge and modified gravity on density irregularities

    Energy Technology Data Exchange (ETDEWEB)

    Bhatti, M.Z. Ul Haq; Yousaf, Z. [University of the Punjab, Department of Mathematics, Lahore (Pakistan)

    2016-04-15

    This work aims to identify some inhomogeneity factors for a plane symmetric topology with anisotropic and dissipative fluid under the effects of both electromagnetic field as well as Palatini f(R) gravity. We construct the modified field equations, kinematical quantities, and mass function to continue our analysis. We have explored the dynamical quantities, conservation equations and modified Ellis equations with the help of a viable f(R) model. Some particular cases are discussed with and without dissipation to investigate the corresponding inhomogeneity factors. For a non-radiating scenario, we examine such factors as dust, and isotropic and anisotropic matter in the presence of charge. For a dissipative fluid, we investigate the inhomogeneity factor with a charged dust cloud. We conclude that the electromagnetic field increases the inhomogeneity in matter while the extra curvature terms make the system more homogeneous with the evolution of time. (orig.)

  12. Molecular Weight and Charge Density Asymmetry in Polyelectrolyte Complexation

    Science.gov (United States)

    Audus, Debra; Fredrickson, Glenn; Duechs, Dominik

    2009-03-01

    We investigate the phase diagram of oppositely charged polymers in a good solvent using a field-theoretic model. Mean-field solutions fail to predict the experimentally observed macroscopic phase separation into a solvent-rich phase and a dense liquid aggregate of polymers - a ``complex coacervate.'' We therefore study the model within a one-loop approximation, which accounts for Gaussian fluctuations in electrostatic and chemical potentials. Our particular focus is the effect of molecular weight, ionic strength, and charge asymmetry on the phase envelope. A set of dimensionless parameters is identified that dictate the size and shape of the two-phase region. Our results should be helpful in guiding experimental studies of coacervation.

  13. Melting Point Of Metals In Relation Io Electron Charge Density

    Directory of Open Access Journals (Sweden)

    Boczkal G.

    2015-09-01

    Full Text Available The concept of spatial criterion of the electron charge concentration is applied to determine the metal melting point. Based on the model proposed for bcc metals, a model for hcp metals and general form for others has been developed. To calculate the melting point, only structural data and atomic number are required. The obtained results show good consistency with the experimental data for metals with atomic number Z < 70.

  14. Peltier effect in multilayered nanopillars under high density charge current

    Science.gov (United States)

    Gravier, L.; Fukushima, A.; Kubota, H.; Yamamoto, A.; Yuasa, S.

    2006-12-01

    From the basic equations of thermoelectricity, we model the thermal regimes that develop in multilayered nanopillar elements experiencing continuous charge currents. The energy conservation principle was applied to all layer-layer and layer-electrode junctions. The obtained set of equations was solved to derive the temperature of each junction. The contribution of the Peltier effect is included in an effective resistance. This model gives satisfactory fits to experimental data obtained on a series of reference nanopillar elements.

  15. Peltier effect in multilayered nanopillars under high density charge current

    Energy Technology Data Exchange (ETDEWEB)

    Gravier, L [Institut de Physique des Nanostructures, Ecole Polytechnique Federale de Lausanne (EPFL), EPFL-SB-IPN station 3, 1015 Lausanne (Switzerland); Fukushima, A [National Institute of Advances Industrial Science and Technology (AIST) 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Kubota, H [National Institute of Advances Industrial Science and Technology (AIST) 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Yamamoto, A [National Institute of Advances Industrial Science and Technology (AIST) 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Yuasa, S [National Institute of Advances Industrial Science and Technology (AIST) 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2006-12-21

    From the basic equations of thermoelectricity, we model the thermal regimes that develop in multilayered nanopillar elements experiencing continuous charge currents. The energy conservation principle was applied to all layer-layer and layer-electrode junctions. The obtained set of equations was solved to derive the temperature of each junction. The contribution of the Peltier effect is included in an effective resistance. This model gives satisfactory fits to experimental data obtained on a series of reference nanopillar elements.

  16. Charged plate in asymmetric electrolytes: One-loop renormalization of surface charge density and Debye length due to ionic correlations

    Science.gov (United States)

    Ding, Mingnan; Lu, Bing-Sui; Xing, Xiangjun

    2016-10-01

    Self-consistent field theory (SCFT) is used to study the mean potential near a charged plate inside a m :-n electrolyte. A perturbation series is developed in terms of g =4 π κ b , where b a n d 1 /κ are Bjerrum length and bare Debye length, respectively. To the zeroth order, we obtain the nonlinear Poisson-Boltzmann theory. For asymmetric electrolytes (m ≠n ), the first order (one-loop) correction to mean potential contains a secular term, which indicates the breakdown of the regular perturbation method. Using a renormalizaton group transformation, we remove the secular term and obtain a globally well-behaved one-loop approximation with a renormalized Debye length and a renormalized surface charge density. Furthermore, we find that if the counterions are multivalent, the surface charge density is renormalized substantially downwards and may undergo a change of sign, if the bare surface charge density is sufficiently large. Our results agrees with large MC simulation even when the density of electrolytes is relatively high.

  17. Charge-density analysis of 1-nitroindoline: refinement quality using free R factors and restraints.

    Science.gov (United States)

    Zarychta, Bartosz; Zaleski, Jacek; Kyzioł, Janusz; Daszkiewicz, Zdzisław; Jelsch, Christian

    2011-06-01

    Nitramines and related N-nitro compounds have attracted significant attention owing to their use in rocket fuel and as explosives. The charge density of 1-nitroindoline was determined experimentally and from theoretical calculations. Electron-density refinements were performed using the multipolar atom formalism. In order to design the ideal restraint strategy for the charge-density parameters, R-free analyses were performed involving a series of comprehensive refinements. Different weights were applied to the charge-density restraints, namely the similarity between chemically equivalent atoms and local symmetry. Additionally, isotropic thermal motion and an anisotropic model calculated by rigid-body analysis were tested on H atoms. The restraint weights which resulted in the lowest values of the averaged R-free factors and the anisotropic H-atom model were considered to yield the best charge density and were used in the final refinement. The derived experimental charge density along with intra- and intermolecular interactions was analysed and compared with theoretical calculations, notably with respect to the symmetry of multipole parameters. A comparison of different refinements suggests that the appropriate weighting scheme applied to charge-density restraints can reduce the observed artefacts. The topological bond orders of the molecule were calculated.

  18. Fractal dimension of the topological charge density distribution in SU(2) lattice gluodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Buividovich, P.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Theoretical and Experimental Physics ITEP, Moscow (Russian Federation); Kalaydzhyan, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Institute for Theoretical and Experimental Physics ITEP, Moscow (Russian Federation); Polikarpov, M.I. [Institute for Theoretical and Experimental Physics ITEP, Moscow (Russian Federation)

    2011-11-15

    We study the effect of cooling on the spatial distribution of the topological charge density in quenched SU(2) lattice gauge theory with overlap fermions. We show that as the gauge field configurations are cooled, the Hausdorff dimension of regions where the topological charge is localized gradually changes from d=2/3 towards the total space dimension. Hence the cooling procedure destroys some of the essential properties of the topological charge distribution. (orig.)

  19. Determination of charge carrier mobility in doped low density polyethylene using DC transients

    DEFF Research Database (Denmark)

    Khalil, M.Salah; Henk, Peter O; Henriksen, Mogens

    1989-01-01

    Charge carrier mobility was determined for plain and doped low-density polyethylene (LDPE) using DC transient currents. Barium titanate was used as a strongly polar dopant and titanium dioxide as a semiconductor dopant. The values of the mobility obtained were on the order of 10-10 cm2 v-1 s-1...... by a factor of five. Charge trapping and space charge formation were modified by the introduction of titanium dioxide...

  20. Mapping surface charge density of lipid bilayers by quantitative surface conductivity microscopy

    Science.gov (United States)

    Klausen, Lasse Hyldgaard; Fuhs, Thomas; Dong, Mingdong

    2016-08-01

    Local surface charge density of lipid membranes influences membrane-protein interactions leading to distinct functions in all living cells, and it is a vital parameter in understanding membrane-binding mechanisms, liposome design and drug delivery. Despite the significance, no method has so far been capable of mapping surface charge densities under physiologically relevant conditions. Here, we use a scanning nanopipette setup (scanning ion-conductance microscope) combined with a novel algorithm to investigate the surface conductivity near supported lipid bilayers, and we present a new approach, quantitative surface conductivity microscopy (QSCM), capable of mapping surface charge density with high-quantitative precision and nanoscale resolution. The method is validated through an extensive theoretical analysis of the ionic current at the nanopipette tip, and we demonstrate the capacity of QSCM by mapping the surface charge density of model cationic, anionic and zwitterionic lipids with results accurately matching theoretical values.

  1. A study of transverse charge density of pions in relativistic quantum mechanics%A study of transverse charge density of pions in relativistic quantum mechanics

    Institute of Scientific and Technical Information of China (English)

    董宇兵; 王翼展

    2011-01-01

    The transverse charge density of pions is calculated based on relativistic quantum mechanics, where the pion is regarded as a quark-antiquark bound state. Corrections from the two spin-1/2 constituents and from the wave function of a quark and antiquark i

  2. Generation of localized magnetic moments in the charge-density-wave state

    OpenAIRE

    Akzyanov, R. S.; Rozhkov, A. V.

    2014-01-01

    We propose a mechanism explaining the generation of localized magnetic moments in charge-density-wave compounds. Our model Hamiltonian describes an Anderson impurity placed in a host material exhibiting the charge-density wave. There is a region of the model's parameter space, where even weak Coulomb repulsion on the impurity site is able to localize the magnetic moment on the impurity. The phase diagram of a single impurity at T=0 is mapped. To establish the connection with experiment thermo...

  3. High Volumetric Energy Density Asymmetric Supercapacitors Based on Well-Balanced Graphene and Graphene-MnO2 Electrodes with Densely Stacked Architectures.

    Science.gov (United States)

    Sheng, Lizhi; Jiang, Lili; Wei, Tong; Fan, Zhuangjun

    2016-10-01

    The well-matched electrochemical parameters of positive and negative electrodes, such as specific capacitance, rate performance, and cycling stability, are important for obtaining high-performance asymmetric supercapacitors. Herein, a facile and cost-effective strategy is demonstrated for the fabrication of 3D densely stacked graphene (DSG) and graphene-MnO2 (G-MnO2 ) architectures as the electrode materials for asymmetric supercapacitors (ASCs) by using MnO2 -intercalated graphite oxide (GO-MnO2 ) as the precursor. DSG has a stacked graphene structure with continuous ion transport network in-between the sheets, resulting in a high volumetric capacitance of 366 F cm(-3) , almost 2.5 times than that of reduced graphene oxide, as well as long cycle life (93% capacitance retention after 10 000 cycles). More importantly, almost similar electrochemical properties, such as specific capacitance, rate performance, and cycling stability, are obtained for DSG as the negative electrode and G-MnO2 as the positive electrode. As a result, the assembled ASC delivers both ultrahigh gravimetric and volumetric energy densities of 62.4 Wh kg(-1) and 54.4 Wh L(-1) (based on total volume of two electrodes) in 1 m Na2 SO4 aqueous electrolyte, respectively, much higher than most of previously reported ASCs in aqueous electrolytes.

  4. A topological analysis of charge densities in diamond, silicon and germanium crystals

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, Yu.A. [National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (Japan); Okamura, F.P. [National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (Japan)

    1997-03-01

    The Hansen-Coppens multipole model of charge density has been fitted to highly accurate published experimental and theoretical structure factors for diamond, silicon and germanium crystals. Analysis of both model experimental and theoretical charge densities using the resulting model parameters was performed in terms of Bader`s topological theory. The general topology of the charge density appeared to be identical for all crystals, containing the four possible types of critical points of rank three, and no non-nuclear attractors between neighboring atoms were found within achieved accuracy. Theoretical and experimental values of charge density and its Laplacian show quantitative and semiquantitative agreement, respectively, at the critical points of model charge densities. For Ge crystals, such agreement is worse at the ring critical point. These results suggest the possibility of semiquantitative (within 10-30%) study of the topological characteristics of highly accurate X-ray charge densities of crystals displaying shared interatomic interactions. Comparative topological analysis of the chemical bond in this series of crystals is discussed in terms of the quantum topological theory. (orig.).

  5. An Analytical Planning Model to Estimate the Optimal Density of Charging Stations for Electric Vehicles.

    Directory of Open Access Journals (Sweden)

    Yongjun Ahn

    Full Text Available The charging infrastructure location problem is becoming more significant due to the extensive adoption of electric vehicles. Efficient charging station planning can solve deeply rooted problems, such as driving-range anxiety and the stagnation of new electric vehicle consumers. In the initial stage of introducing electric vehicles, the allocation of charging stations is difficult to determine due to the uncertainty of candidate sites and unidentified charging demands, which are determined by diverse variables. This paper introduces the Estimating the Required Density of EV Charging (ERDEC stations model, which is an analytical approach to estimating the optimal density of charging stations for certain urban areas, which are subsequently aggregated to city level planning. The optimal charging station's density is derived to minimize the total cost. A numerical study is conducted to obtain the correlations among the various parameters in the proposed model, such as regional parameters, technological parameters and coefficient factors. To investigate the effect of technological advances, the corresponding changes in the optimal density and total cost are also examined by various combinations of technological parameters. Daejeon city in South Korea is selected for the case study to examine the applicability of the model to real-world problems. With real taxi trajectory data, the optimal density map of charging stations is generated. These results can provide the optimal number of chargers for driving without driving-range anxiety. In the initial planning phase of installing charging infrastructure, the proposed model can be applied to a relatively extensive area to encourage the usage of electric vehicles, especially areas that lack information, such as exact candidate sites for charging stations and other data related with electric vehicles. The methods and results of this paper can serve as a planning guideline to facilitate the extensive

  6. An Analytical Planning Model to Estimate the Optimal Density of Charging Stations for Electric Vehicles.

    Science.gov (United States)

    Ahn, Yongjun; Yeo, Hwasoo

    2015-01-01

    The charging infrastructure location problem is becoming more significant due to the extensive adoption of electric vehicles. Efficient charging station planning can solve deeply rooted problems, such as driving-range anxiety and the stagnation of new electric vehicle consumers. In the initial stage of introducing electric vehicles, the allocation of charging stations is difficult to determine due to the uncertainty of candidate sites and unidentified charging demands, which are determined by diverse variables. This paper introduces the Estimating the Required Density of EV Charging (ERDEC) stations model, which is an analytical approach to estimating the optimal density of charging stations for certain urban areas, which are subsequently aggregated to city level planning. The optimal charging station's density is derived to minimize the total cost. A numerical study is conducted to obtain the correlations among the various parameters in the proposed model, such as regional parameters, technological parameters and coefficient factors. To investigate the effect of technological advances, the corresponding changes in the optimal density and total cost are also examined by various combinations of technological parameters. Daejeon city in South Korea is selected for the case study to examine the applicability of the model to real-world problems. With real taxi trajectory data, the optimal density map of charging stations is generated. These results can provide the optimal number of chargers for driving without driving-range anxiety. In the initial planning phase of installing charging infrastructure, the proposed model can be applied to a relatively extensive area to encourage the usage of electric vehicles, especially areas that lack information, such as exact candidate sites for charging stations and other data related with electric vehicles. The methods and results of this paper can serve as a planning guideline to facilitate the extensive adoption of electric

  7. Dimensionality-driven phonon softening and incipient charge density wave instability in TiS2

    Science.gov (United States)

    Dolui, Kapildeb; Sanvito, Stefano

    2016-08-01

    Density functional theory and density functional perturbation theory are used to investigate the electronic and vibrational properties of TiS2. Within the local density approximation the material is a semimetal both in the bulk and in the monolayer form. Most interestingly we observe a Kohn anomaly in the bulk phonon dispersion, which turns into a charge density wave instability when TiS2 is thinned to less than four monolayers. Such instability, however, disappears when one calculates the electronic structure with a functional, such as the LDA+U, which returns an insulating ground state. In this situation charge-doping or strain does not bring back the charge density wave instability, whereas the formation of the TiSSe alloy does.

  8. An Asymmetric Supercapacitor with Both Ultra-High Gravimetric and Volumetric Energy Density Based on 3D Ni(OH)2/MnO2@Carbon Nanotube and Activated Polyaniline-Derived Carbon.

    Science.gov (United States)

    Shen, Juanjuan; Li, Xiaocheng; Wan, Liu; Liang, Kun; Tay, Beng Kang; Kong, Lingbin; Yan, Xingbin

    2017-01-11

    Development of a supercapacitor device with both high gravimetric and volumetric energy density is one of the most important requirements for their practical application in energy storage/conversion systems. Currently, improvement of the gravimetric/volumetric energy density of a supercapacitor is restricted by the insufficient utilization of positive materials at high loading density and the inferior capacitive behavior of negative electrodes. To solve these problems, we elaborately designed and prepared a 3D core-shell structured Ni(OH)2/MnO2@carbon nanotube (CNT) composite via a facile solvothermal process by using the thermal chemical vapor deposition grown-CNTs as support. Owing to the superiorities of core-shell architecture in improving the service efficiency of pseudocapacitive materials at high loading density, the prepared Ni(OH)2/MnO2@CNT electrode demonstrated a high capacitance value of 2648 F g(-1) (1 A g(-1)) at a high loading density of 6.52 mg cm(-2). Coupled with high-performance activated polyaniline-derived carbon (APDC, 400 F g(-1) at 1 A g(-1)), the assembled Ni(OH)2/MnO2@CNT//APDC asymmetric device delivered both high gravimetric and volumetric energy density (126.4 Wh kg(-1) and 10.9 mWh cm(-3), respectively), together with superb rate performance and cycling lifetime. Moreover, we demonstrate an effective approach for building a high-performance supercapacitor with high gravimetric/volumetric energy density.

  9. The angular magnetothermoelectric power of a charge density wave system

    Science.gov (United States)

    Krstovska, D.; Choi, E. S.; Steven, E.; Brooks, J. S.

    2012-07-01

    The angular dependence of the magnetothermopower of a charge transfer organic salt α-(ET)2KHg(SCN)4 below (4 K) and above (9 K) the phase transition temperature, Tp = 8 K, and under fields of 15 T and 25 T, below and above the ‘kinkfield’, has been studied. We find that for a longitudinal thermoelectric measurement both an interlayer thermopower (the Seebeck effect), Szz, and a transverse thermopower (the Nernst effect), Syz, exist in all three different B-T phases (the CDW 0, CDW x and metallic states) with large amplitude. Both thermoelectric effects display a resonant-like behavior without a sign reversal at the angles corresponding to angular magnetoresistance oscillation minima and maxima in this compound. The resonant behavior is most evident in the CDW0 state, indicating a mechanism involving the Fermi surface nesting. Angular dependences reveal different behaviors of the thermopower and Nernst effect in the high magnetic field (CDWx) state.

  10. A relativistic non-relativistic Goldstone theorem: gapped Goldstones at finite charge density

    CERN Document Server

    Nicolis, Alberto

    2012-01-01

    We adapt the Goldstone theorem to study spontaneous symmetry breaking in relativistic theories at finite charge density. It is customary to treat systems at finite density via non-relativistic Hamiltonians. Here we highlight the importance of the underlying relativistic dynamics. This leads to seemingly new results whenever the charge in question is spontaneously broken and does not commute with other broken charges. These would normally be associated with gapless Goldstone excitations. We find that, in fact, their currents interpolate gapped excitations. We derive exact non-perturbative expressions for their gaps, in terms of the chemical potential and of the symmetry algebra.

  11. Single-charge-exchange reactions and the neutron density at the surface of the nucleus

    Science.gov (United States)

    Loc, Bui Minh; Auerbach, Naftali; Khoa, Dao T.

    2017-07-01

    In this paper, we study the charge-exchange reaction to the isobaric analog state using two types of transition densities. One transition density is equal to the difference of the total neutron density minus the total proton density and the other one is the density of the excess neutrons only. We show that for projectiles that do not probe the interior of the nucleus but mostly the surface of this nucleus, distinct differences in the cross section arise when two types of transition densities are employed. We demonstrate this by considering the (3He,t ) reaction.

  12. Like-Charge Attraction between Polyelectrolytes Induced by Counterion Charge Density Waves

    National Research Council Canada - National Science Library

    Thomas E. Angelini; Hongjun Liang; Willy Wriggers; Gerard C. L. Wong

    2003-01-01

    ...) Intermolecular and Surface Forces (Academic, London), 2nd ed.]. Like-charge attractions, however, have been observed in a variety of systems [Gelbart, W. M., Bruinsma, R. F., Pincus, P. A. & Parsegian, V. A. (2000) Phys. Today 53, 38-44...

  13. Volumetric composition of nanocomposites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Mannila, Juha

    2015-01-01

    Detailed characterisation of the properties of composite materials with nanoscale fibres is central for the further progress in optimization of their manufacturing and properties. In the present study, a methodology for the determination and analysis of the volumetric composition of nanocomposites...... is presented, using cellulose/epoxy and aluminosilicate/polylactate nanocomposites as case materials. The buoyancy method is used for the accurate measurements of materials density. The accuracy of the method is determined to be high, allowing the measured nanocomposite densities to be reported with 5...... significant figures. The plotting of the measured nanocomposite density as a function of the nanofibre weight content is shown to be a first good approach of assessing the porosity content of the materials. The known gravimetric composition of the nanocomposites is converted into a volumetric composition...

  14. d-Density Wave Scenario Description of the New Hidden Charge Order in Cuprates

    Science.gov (United States)

    Makhfudz, Imam

    2016-06-01

    In this paper, we show that the theory of high Tc superconductivity based on a microscopic model with d-density wave (DDW) scenario in the pseudogap phase is able to reproduce some of the most important features of the recent experimentally discovered hidden charge order in several families of Cuprates. In particular, by computing and comparing energies of charge orders of different modulation directions derived from a full microscopic theory with d-density wave scenario, the axial charge order ϕX(Y) with wavevector Q = (Q0,0)((0,Q0)) is shown to be unambiguously energetically more favorable over the diagonal charge order ϕX±Y with wavevector Q = (Q0, ± Q0) at least in commensurate limit, to be expected also to hold even to more general incommensurate case, in agreement with experiment. The two types of axial charge order ϕX and ϕY are degenerate by symmetry. We find that within the superconducting background, biaxial (checkerboard) charge order is energetically more favorable than uniaxial (stripe) charge order, and therefore checkerboard axial charge order should be the one observed in experiments, assuming a single domain of charge ordered state on each CuO2 plane.

  15. Space charge profiles in low density polyethylene samples containing a permittivity/conductivity gradient

    DEFF Research Database (Denmark)

    Bambery, K.R.; Fleming, R.J.; Holbøll, Joachim

    2001-01-01

    .5×107 V m-1. Current density was also measured as a function of temperature and field. Space charge due exclusively to the temperature gradient was detected, with density of order 0.01 C m-3. The activation energy associated with the transport of electrons through the bulk was calculated as 0.09 e...

  16. Space charge profiles in low density polyethylene samples containing a permittivity/conductivity gradient

    DEFF Research Database (Denmark)

    Bambery, K.R.; Fleming, R.J.; Holbøll, Joachim

    2001-01-01

    Laser induced pressure pulse space charge measurements were made on 1.5 mm thick plaques of high purity low density polyethylene equipped with vacuum-evaporated aluminium electrodes. Temperature differences up to 20 °C were maintained across the samples, which were subjected to dc fields up to 1.......5×107 V m-1. Current density was also measured as a function of temperature and field. Space charge due exclusively to the temperature gradient was detected, with density of order 0.01 C m-3. The activation energy associated with the transport of electrons through the bulk was calculated as 0.09 e...

  17. Isovector coupling channel and central properties of the charge density distribution in heavy spherical nuclei

    Indian Academy of Sciences (India)

    S Haddad

    2010-09-01

    The influence of the isovector coupling channel on the central depression parameter and the central value of the charge density distribution in heavy spherical nuclei was studied. The isovector coupling channel leads to about 50% increase of the central depression parameter, and weakens the dependency of both central depression parameter and central density on the asymmetry, impressively contributing to the semibubble form of the charge density distribution in heavy nuclei, and increasing the probability of larger nuclei with higher proton numbers and higher neutron-to-proton ratios stable.

  18. Density Functional Theory Approach for Charged Hard Sphere Fluids Confined in Spherical Micro-Cavity

    Institute of Scientific and Technical Information of China (English)

    KANG Yan-Shuang; WANG Hai-Jun

    2009-01-01

    Within the framework of the density functional theory for classical fluids,the equilibrium density profiles of charged hard sphere fluid confined in micro-cavity are studied by means of the modified fundamental measure theory.The dimension of micro-cavity,the charge of hard sphere and the applied electric field are found to have significant effects on the density profiles.In particular,it is shown that Coulomb interaction,excluded volume interaction and applied electric Geld play the central role in controlling the aggregated structure of the system.

  19. Effect of Polyester and Plaster of Paris Casts on Determination of Volumetric Bone Mineral Density Assessed by Peripheral Quantitative Computed Tomography (pQCT).

    Science.gov (United States)

    Bullen, Michael; Blanchard, Romane; Rodda, Christine; Pivonka, Peter

    2016-11-01

    Peripheral quantitative computed tomography (pQCT) is a non-invasive, low-radiation tool for measuring volumetric bone mineral density. It has potential for use in fracture healing applications; however, the unknown attenuation effects of cast material on peripheral quantitative computed tomography have contributed to its limited use in this area. The effect of two common cast materials, polyester and Plaster of Paris was investigated by performing both in vitro and in vivo studies. The in vitro study tested the effect of increasing layers of cast material on bone density measurements performed on a hydroxyapatite phantom. Cast thickness was directly associated with a reduction in bone mineral density, with twelve layers of polyester and Plaster of Paris resulting in a 0.55 and 2.21 % decrease in bone density measurements. Precision error in situ with polyester cast material was 0.71 %, and 2.31 % with Plaster of Paris cast material. The in vivo study comprised a prospective trial with 28 healthy adult participants to evaluate the effect of the two cast materials. Trabecular bone mineral density was increased by 0.5 % in the presence of a polyester cast and decreased by 4.22 % in the presence of a Plaster of Paris cast. Cortical bone mineral density was decreased by 3.46 and 5.54 % for polyester and Plaster of Paris, respectively. This study quantified the effects of orthopaedic casts on pQCT-derived bone parameters. The results suggest applicability of commonly utilised cast materials in combination with pQCT to assess fracture healing.

  20. Exploring charge density analysis in crystals at high pressure: data collection, data analysis and advanced modelling.

    Science.gov (United States)

    Casati, Nicola; Genoni, Alessandro; Meyer, Benjamin; Krawczuk, Anna; Macchi, Piero

    2017-08-01

    The possibility to determine electron-density distribution in crystals has been an enormous breakthrough, stimulated by a favourable combination of equipment for X-ray and neutron diffraction at low temperature, by the development of simplified, though accurate, electron-density models refined from the experimental data and by the progress in charge density analysis often in combination with theoretical work. Many years after the first successful charge density determination and analysis, scientists face new challenges, for example: (i) determination of the finer details of the electron-density distribution in the atomic cores, (ii) simultaneous refinement of electron charge and spin density or (iii) measuring crystals under perturbation. In this context, the possibility of obtaining experimental charge density at high pressure has recently been demonstrated [Casati et al. (2016). Nat. Commun. 7, 10901]. This paper reports on the necessities and pitfalls of this new challenge, focusing on the species syn-1,6:8,13-biscarbonyl[14]annulene. The experimental requirements, the expected data quality and data corrections are discussed in detail, including warnings about possible shortcomings. At the same time, new modelling techniques are proposed, which could enable specific information to be extracted, from the limited and less accurate observations, like the degree of localization of double bonds, which is fundamental to the scientific case under examination.

  1. A numerical study on charged-particle scattering and radiography of a steep density gradient

    Science.gov (United States)

    Shao, Guangchao; Wang, Xiaofang

    2016-09-01

    Electron and proton radiography of polystyrene planar targets with different density gradients is studied by Monte Carlo simulations in a regime that the incident charged-particle's kinetic energy is much higher than its energy loss in the targets. It is shown that by scattering of the electrons or protons, the density gradient causes modulations of the charged-particle beam transmitted from the target and the modulation contrast is sensitive only to a steep gradient, which suggests a novel diagnostic method wherein a steep density gradient could be distinguished from the scattering of a charged-particle beam in radiography. By using a 100-MeV charged-particle beam, it is found that the modulation is evident for a steep density gradient of width smaller than 1 μm for electron radiography and 0.6 μm for proton radiography, respectively, but almost negligible when the density gradient width is greater than 1 μm. The feasibility of diagnosing the steep density gradients in compressed matter is confirmed by the simulations of radiographing a laser-ablated planar foil. Simulations also show that it is possible to diagnose the density gradients inside a multilayered spherical capsule.

  2. Direct Observation of Spin- and Charge-Density Waves in a Luttinger Liquid

    Science.gov (United States)

    Cao, Chenglin; Marcum, Andrew; Mawardi Ismail, Arif; Fonta, Francisco; O'Hara, Kenneth

    2016-05-01

    At low energy, interacting fermions in one dimension (e.g. electrons in quantum wires or fermionic atoms in 1D waveguides) should behave as Luttinger liquids. In stark contrast to Fermi liquids, the low-energy elementary excitations in Luttinger liquids are collective sound-like modes that propagate independently as spin-density and/or charge-density (i.e. particle-density) waves with generally unequal, and interaction-dependent, velocities. Here we aim to unambiguously confirm this hallmark feature of the Luttinger liquid - the phenomenon of spin-charge separation - by directly observing in real space the dynamics of spin-density and ``charge''-density waves excited in an ultracold gas of spin-1/2 fermions confined in an array of 1D optical waveguides. Starting from a two-component mixture of 6 Li atoms harmonically confined along each of the 1D waveguides, we excite low lying normal modes of the trapped system - namely the spin dipole and density dipole and quadrupole modes - and measure their frequency as a function of interaction strength. Luttinger liquid theory predicts that the spin dipole frequency is strongly dependent on interaction strength whereas the density dipole and quadrupole mode frequencies are relatively insensitive. We will also discuss extending our approach to exciting localized spin density and particle density wavepackets which should propagate at different velocities. Supported by AFOSR and NSF.

  3. Theoretical study of the central depression of nuclear charge density distribution by electron scattering

    Institute of Scientific and Technical Information of China (English)

    LIU Jian; CHU Yan-Yun; REN Zhong-Zhou; WANG Zai-Jun

    2012-01-01

    The charge form factors of elastic electron scattering for isotones with N =20 and N =28 are calculated using the phase-shift analysis method,with corresponding charge density distributions from relativistic mean-field theory.The results show that there are sharp variations at the inner parts of charge distributions with the proton number decreasing.The corresponding charge form factors are divided into two groups because of the unique properties of the s-states wave functions,though the proton numbers change uniformly in two isotonic chains.Meanwhile,the shift regularities of the minima are also discussed,and we give a clear relation between the minima of the charge form factors and the corresponding charge radii.This relation is caused by the diffraction effect of the electron.Under this conclusion,we calculate the charge density distributions and the charge form factors of the A =44 nuclei chain.The results are also useful for studying the central depression in light exotic nuclei.

  4. Charge density modification of carboxylated cellulose nanocrystals for stable silver nanoparticles suspension preparation

    Energy Technology Data Exchange (ETDEWEB)

    Hoeng, Fanny; Denneulin, Aurore [Université Grenoble Alpes, LGP2 (France); Neuman, Charles [Poly-Ink (France); Bras, Julien, E-mail: julien.bras@grenoble-inp.fr [Université Grenoble Alpes, LGP2 (France)

    2015-06-15

    Synthesis of silver nanoparticles using cellulose nanocrystals (CNC) has been found to be a great method for producing metallic particles in a sustainable way. In this work, we propose to evaluate the influence of the charge density of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-oxidized CNC on the morphology and the stability of synthetized silver nanoparticles. Silver nanoparticles were obtained by sol–gel reaction using borohydride reduction, and charge density of TEMPO-oxidized CNC was tuned by an amine grafting. The grafting was performed at room temperature and neutral pH. Crystallinity and morphology were kept intact during the peptidic reaction on CNC allowing knowing the exact impact of the charge density. Charge density has been found to have a strong impact on shape, organization, and suspension stability of resulting silver particles. Results show an easy way to tune the charge density of CNC and propose a sustainable way to control the morphology and stability of silver nanoparticles in aqueous suspension.

  5. Assessment of volumetric bone mineral density of the femoral neck in postmenopausal women with and without vertebral fractures using quantitative multi-slice CT

    Institute of Scientific and Technical Information of China (English)

    Sheng-yong WU; Hui-hui JIA; Didier HANS; Jing LAN; Li-ying WANG; Jing-xue LI; Yue-zeng CAI

    2009-01-01

    Objective: To demonstrate the validity and reliability of volumetric quantitative computed tomography (vQCT) with multi-slice computed tomography (MSCT) and dual energy X-ray absorptiometry (DXA) for hip bone mineral density (BMD) measurements, and to compare the differences between the two techniques in discriminating postmenopausal women with osteoporosis-related vertebral fractures from those without. Methods: Ninety subjects were enrolled and divided into three groups based on the BMD values of the lumbar spine and/or the femoral neck by DXA. Groups 1 and 2 consisted of postmenopausal women with BMD changes <-2SD, with and without radiographically confirmed vertebral fracture (n=11 and 33, respectively).Group 3 comprised normal controls with BMD changes ≥-1SD (n=46). Post-MSCT (GE, LightSpeed16) scan reconstructed images of the abdominal-pelvic region, 1.25 mm thick per slice, were processed by OsteoCAD software to calculate the following parameters: volumetric BMD values of trabecular bone (TRAB), cortical bone (CORT), and integral bone (INTGL) of the left femoral neck, femoral neck axis length (NAL), and minimum cross-section area (mCSA). DXA BMD measurements of the lumbar spine (AP-SPINE) and the left femoral neck (NECK) also were performed for each subject. Results: The values of all seven parameters were significantly lower in subjects of Groups 1 and 2 than in normal postmenopausal women (P<0.05, respectively).Comparing Groups 1 and 2, 3D-TRAB and 3D-INTGL were significantly lower in postmenopausal women with vertebral fracture(s) [(109.8±9.61) and (243.3±33.0) mg/cm3, respectively] than in those without [(148.9±7.47) and (285.4±17.8) mg/cm3,respectively] (P<0.05, respectively), but no significant differences were evident in AP-SPINE or NECK BMD. Conclusion: the femoral neck-derived volumetric BMD parameters using vQCT appeared better than the DXA-derived ones in discriminating osteoporotic postmenopausal women with vertebral fractures from

  6. Low Density Phases in a Uniformly Charged Liquid

    Science.gov (United States)

    Knüpfer, Hans; Muratov, Cyrill B.; Novaga, Matteo

    2016-07-01

    This paper is concerned with the macroscopic behavior of global energy minimizers in the three-dimensional sharp interface unscreened Ohta-Kawasaki model of diblock copolymer melts. This model is also referred to as the nuclear liquid drop model in the studies of the structure of highly compressed nuclear matter found in the crust of neutron stars, and, more broadly, is a paradigm for energy-driven pattern forming systems in which spatial order arises as a result of the competition of short-range attractive and long-range repulsive forces. Here we investigate the large volume behavior of minimizers in the low volume fraction regime, in which one expects the formation of a periodic lattice of small droplets of the minority phase in a sea of the majority phase. Under periodic boundary conditions, we prove that the considered energy {Γ}-converges to an energy functional of the limit "homogenized" measure associated with the minority phase consisting of a local linear term and a non-local quadratic term mediated by the Coulomb kernel. As a consequence, asymptotically the mass of the minority phase in a minimizer spreads uniformly across the domain. Similarly, the energy spreads uniformly across the domain as well, with the limit energy density minimizing the energy of a single droplet per unit volume. Finally, we prove that in the macroscopic limit the connected components of the minimizers have volumes and diameters that are bounded above and below by universal constants, and that most of them converge to the minimizers of the energy divided by volume for the whole space problem.

  7. Experimental charge density of hematite in its magnetic low temperature and high temperature phases

    Energy Technology Data Exchange (ETDEWEB)

    Theissmann, R., E-mail: ralf.theissmann@kronosww.com [Faculty of Engineering and CeNIDE (Center for NanoIntegration Duisburg-Essen), University of Duisburg-Essen, Bismarckstr. 81, 47057 Duisburg (Germany); Fuess, H. [Institute for Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); Tsuda, K. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, 980-8577 Sendai (Japan)

    2012-09-15

    Structural parameters of hematite ({alpha}-Fe{sub 2}O{sub 3}), including the valence electron distribution, were investigated using convergent beam electron diffraction (CBED) in the canted antiferromagnetic phase at room temperature and in the collinear antiferromagnetic phase at 90 K. The refined charge density maps are interpreted as a direct result of electron-electron interaction in a correlated system. A negative deformation density was observed as a consequence of closed shell interaction. Positive deformation densities are interpreted as a shift of electron density to antibinding molecular orbitals. Following this interpretation, the collinear antiferromagnetic phase shows the characteristic of a Mott-Hubbard type insulator whereas the high temperature canted antiferromagnetic phase shows the characteristic of a charge transfer insulator. The break of the threefold symmetry in the canted antiferromagnetic phase was correlated to the presence of oxygen-oxygen bonding, which is caused by a shift of spin polarized charge density from iron 3d-orbitals to the oxygen ions. We propose a triangular magnetic coupling in the oxygen planes causing a frustrated triangular spin arrangement with all spins lying in the oxygen planes. This frustrated arrangement polarizes the super-exchange between iron ions and causes the spins located at the iron ions to orient in the same plane, perpendicular to the threefold axis. -- Highlights: Black-Right-Pointing-Pointer Quantitative CBED was used to study hematite ({alpha}-Fe2O3). Black-Right-Pointing-Pointer Structure and charge density of both antiferromagnetic phases were investigated. Black-Right-Pointing-Pointer Topological charge density analysis was combined with a Bader analysis. Black-Right-Pointing-Pointer A transition from a Mott-Hubbard to a charge transfer insulator is proposed. Black-Right-Pointing-Pointer A frustrated triangular magnetic coupling in the oxygen planes is proposed.

  8. Effects of charge density and hydrophobicity of poly(amido amine)s for non-viral gene delivery

    NARCIS (Netherlands)

    Piest, Martin; Engbersen, Johan F.J.

    2010-01-01

    High cationic charge densities in polymeric vectors result in tight DNA condensation, leading to small highly positively charged polyplexes which show generally high cellular uptake in vitro. However, high cationic charge densities also introduce membrane-disruptive properties to the polymers, there

  9. Charge carrier density dependence of the hole mobility in poly(p-phenylene vinylene)

    OpenAIRE

    Tanase, C; Blom, PWM; De Leeuw, DM; de Meijer, EJ

    2004-01-01

    The hole transport in various poly(p-phenylene vinylene) (PPV) derivatives has been investigated in field-effect transistors (FETs) and light-emitting diodes (LEDs) as a function of temperature and applied bias. The discrepancy between the experimental hole mobilities extracted from FETs and LEDs based on a single disordered polymeric semiconductor originates from the strong dependence of the hole mobility on the charge carrier density. The microscopic charge transport parameters are directly...

  10. Vortex Dynamics in Selfdual Maxwell-Higgs Systems with Uniform Background Electric Charge Density

    CERN Document Server

    Lee, K M

    1994-01-01

    We introduce selfdual Maxwell-Higgs systems with uniform background electric charge density and show that the selfdual equations satisfied by topological vortices can be reduced to the original Bogomol'nyi equations without any background. These vortices are shown to carry no spin but to feel the Magnus force due to the shielding charge carried by the Higgs field. We also study the dynamics of slowly moving vortices and show that the spin-statistics theorem holds to our vortices.

  11. Energy and centrality dependences of charged multiplicity pseudorapidity density in relativistic nuclear collisions

    CERN Document Server

    Zhou Dai Mei; Sá Ben-Hao; Li Zhong Dao

    2002-01-01

    Using a hadron and string cascade model, JPCIAE, and the corresponding Monte Carlo events generator, the energy and centrality dependences of charged particle pseudorapidity density in relativistic nuclear collisions were studied. Within the framework of this model, both the relativistic p anti p experimental data and the PHOBOS and PHENIX Au + Au data could be reproduced fairly well without retuning the model parameters. The author shows that since is not a well defined physical variable both experimentally and theoretically, the charged particle pseudorapidity density per participant pair can increase and also can decrease with increasing of , so it may be hard to use charged particle pseudorapidity density per participant pair as a function of to distinguish various theoretical models for particle production

  12. Charge-carrier mobilities in disordered semiconducting polymers: effects of carrier density and electric field

    Science.gov (United States)

    Meisel, K. D.; Pasveer, W. F.; Cottaar, J.; Tanase, C.; Coehoorn, R.; Bobbert, P. A.; Blom, P. W. M.; de Leeuw, D. M.; Michels, M. A. J.

    2006-02-01

    We model charge transport in disordered semiconducting polymers by hopping of charge carriers on a square lattice of sites with Gaussian on-site energy disorder, using Fermi-Dirac statistics. From numerically exact solutions of the Master equation, we study the dependence of the charge-carrier mobility on temperature, carrier density, and electric field. Our results are used in calculating current-voltage characteristics of hole-only polymer diodes. It is found that very good fits to experimental current-voltage characteristics can be obtained at different temperatures, with reasonable fitting parameters for the width of the Gaussian density of states and the lattice constant. In agreement with the experiments we find that the density dependence is dominant over the field dependence. Only at high fields and low temperatures the field dependence becomes noticeable. The potential and current distribution show strong inhomogeneities, which may have important consequences for the operation of polymer opto-electronic devices.

  13. Mapping surface charge density of lipid bilayers by quantitative surface conductivity microscopy

    DEFF Research Database (Denmark)

    Klausen, Lasse Hyldgaard; Fuhs, Thomas; Dong, Mingdong

    2016-01-01

    Local surface charge density of lipid membranes influences membrane-protein interactions leading to distinct functions in all living cells, and it is a vital parameter in understanding membrane-binding mechanisms, liposome design and drug delivery. Despite the significance, no method has so far...... approach, quantitative surface conductivity microscopy (QSCM), capable of mapping surface charge density with high-quantitative precision and nanoscale resolution. The method is validated through an extensive theoretical analysis of the ionic current at the nanopipette tip, and we demonstrate the capacity...... been capable of mapping surface charge densities under physiologically relevant conditions. Here, we use a scanning nanopipette setup (scanning ion-conductance microscope) combined with a novel algorithm to investigate the surface conductivity near supported lipid bilayers, and we present a new...

  14. Determinants of the reliability of ultrasound tomography sound speed estimates as a surrogate for volumetric breast density

    Energy Technology Data Exchange (ETDEWEB)

    Khodr, Zeina G.; Pfeiffer, Ruth M.; Gierach, Gretchen L., E-mail: GierachG@mail.nih.gov [Department of Health and Human Services, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 9609 Medical Center Drive MSC 9774, Bethesda, Maryland 20892 (United States); Sak, Mark A.; Bey-Knight, Lisa [Karmanos Cancer Institute, Wayne State University, 4100 John R, Detroit, Michigan 48201 (United States); Duric, Nebojsa; Littrup, Peter [Karmanos Cancer Institute, Wayne State University, 4100 John R, Detroit, Michigan 48201 and Delphinus Medical Technologies, 46701 Commerce Center Drive, Plymouth, Michigan 48170 (United States); Ali, Haythem; Vallieres, Patricia [Henry Ford Health System, 2799 W Grand Boulevard, Detroit, Michigan 48202 (United States); Sherman, Mark E. [Division of Cancer Prevention, National Cancer Institute, Department of Health and Human Services, 9609 Medical Center Drive MSC 9774, Bethesda, Maryland 20892 (United States)

    2015-10-15

    Purpose: High breast density, as measured by mammography, is associated with increased breast cancer risk, but standard methods of assessment have limitations including 2D representation of breast tissue, distortion due to breast compression, and use of ionizing radiation. Ultrasound tomography (UST) is a novel imaging method that averts these limitations and uses sound speed measures rather than x-ray imaging to estimate breast density. The authors evaluated the reproducibility of measures of speed of sound and changes in this parameter using UST. Methods: One experienced and five newly trained raters measured sound speed in serial UST scans for 22 women (two scans per person) to assess inter-rater reliability. Intrarater reliability was assessed for four raters. A random effects model was used to calculate the percent variation in sound speed and change in sound speed attributable to subject, scan, rater, and repeat reads. The authors estimated the intraclass correlation coefficients (ICCs) for these measures based on data from the authors’ experienced rater. Results: Median (range) time between baseline and follow-up UST scans was five (1–13) months. Contributions of factors to sound speed variance were differences between subjects (86.0%), baseline versus follow-up scans (7.5%), inter-rater evaluations (1.1%), and intrarater reproducibility (∼0%). When evaluating change in sound speed between scans, 2.7% and ∼0% of variation were attributed to inter- and intrarater variation, respectively. For the experienced rater’s repeat reads, agreement for sound speed was excellent (ICC = 93.4%) and for change in sound speed substantial (ICC = 70.4%), indicating very good reproducibility of these measures. Conclusions: UST provided highly reproducible sound speed measurements, which reflect breast density, suggesting that UST has utility in sensitively assessing change in density.

  15. Trapped charge densities in Al2O3-based silicon surface passivation layers

    Science.gov (United States)

    Jordan, Paul M.; Simon, Daniel K.; Mikolajick, Thomas; Dirnstorfer, Ingo

    2016-06-01

    In Al2O3-based passivation layers, the formation of fixed charges and trap sites can be strongly influenced by small modifications in the stack layout. Fixed and trapped charge densities are characterized with capacitance voltage profiling and trap spectroscopy by charge injection and sensing, respectively. Al2O3 layers are grown by atomic layer deposition with very thin (˜1 nm) SiO2 or HfO2 interlayers or interface layers. In SiO2/Al2O3 and HfO2/Al2O3 stacks, both fixed charges and trap sites are reduced by at least a factor of 5 compared with the value measured in pure Al2O3. In Al2O3/SiO2/Al2O3 or Al2O3/HfO2/Al2O3 stacks, very high total charge densities of up to 9 × 1012 cm-2 are achieved. These charge densities are described as functions of electrical stress voltage, time, and the Al2O3 layer thickness between silicon and the HfO2 or the SiO2 interlayer. Despite the strong variation of trap sites, all stacks reach very good effective carrier lifetimes of up to 8 and 20 ms on p- and n-type silicon substrates, respectively. Controlling the trap sites in Al2O3 layers opens the possibility to engineer the field-effect passivation in the solar cells.

  16. Charge transport in disordered organic host-guest systems: effects of carrier density and electric field

    Energy Technology Data Exchange (ETDEWEB)

    Yimer, Y Y; Bobbert, P A [Group Polymer Physics, Eindhoven Polymer Laboratories and Dutch Polymer Institute, 5600 MB Eindhoven (Netherlands); Coehoorn, R [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)], E-mail: Y.Y.Yimer@tue.nl

    2008-08-20

    We investigate charge transport in disordered organic host-guest systems with a bimodal Gaussian density of states (DOS). The energy difference between the two Gaussians defines the trap depth. By solving the Pauli master equation for the hopping of charge carriers on a regular lattice with site energies randomly drawn from the DOS, we obtain the dependence of the charge-carrier mobility on the relative guest concentration, the trap depth, the energetic disorder, the charge-carrier density and the electric field. At small and high guest concentrations, our work provides support for recent semi-analytical model results on the dependence of the mobility on the charge-carrier density at zero field. However, at the cross-over between the trap-limited and trap-to-trap hopping regimes, where the mobility attains a minimum, our results can almost be one order of magnitude larger than predicted semi-analytically. Furthermore, it is shown that field-induced detrapping can contribute strongly to the electric-field dependence of the mobility. A simple analytical expression is provided which describes the effect. This result can be used in continuum drift-diffusion models for charge transport in devices such as organic light-emitting diodes.

  17. Charge transport in disordered organic host guest systems: effects of carrier density and electric field

    Science.gov (United States)

    Yimer, Y. Y.; Bobbert, P. A.; Coehoorn, R.

    2008-08-01

    We investigate charge transport in disordered organic host-guest systems with a bimodal Gaussian density of states (DOS). The energy difference between the two Gaussians defines the trap depth. By solving the Pauli master equation for the hopping of charge carriers on a regular lattice with site energies randomly drawn from the DOS, we obtain the dependence of the charge-carrier mobility on the relative guest concentration, the trap depth, the energetic disorder, the charge-carrier density and the electric field. At small and high guest concentrations, our work provides support for recent semi-analytical model results on the dependence of the mobility on the charge-carrier density at zero field. However, at the cross-over between the trap-limited and trap-to-trap hopping regimes, where the mobility attains a minimum, our results can almost be one order of magnitude larger than predicted semi-analytically. Furthermore, it is shown that field-induced detrapping can contribute strongly to the electric-field dependence of the mobility. A simple analytical expression is provided which describes the effect. This result can be used in continuum drift-diffusion models for charge transport in devices such as organic light-emitting diodes.

  18. The relationships between breast volume, breast dense volume and volumetric breast density with body mass index, body fat mass and ethnicity

    Science.gov (United States)

    Zakariyah, N.; Pathy, N. B.; Taib, N. A. M.; Rahmat, K.; Judy, C. W.; Fadzil, F.; Lau, S.; Ng, K. H.

    2016-03-01

    It has been shown that breast density and obesity are related to breast cancer risk. The aim of this study is to investigate the relationships of breast volume, breast dense volume and volumetric breast density (VBD) with body mass index (BMI) and body fat mass (BFM) for the three ethnic groups (Chinese, Malay and Indian) in Malaysia. We collected raw digital mammograms from 2450 women acquired on three digital mammography systems. The mammograms were analysed using Volpara software to obtain breast volume, breast dense volume and VBD. Body weight, BMI and BFM of the women were measured using a body composition analyser. Multivariable logistic regression was used to determine the independent predictors of increased overall breast volume, breast dense volume and VBD. Indians have highest breast volume and breast dense volume followed by Malays and Chinese. While Chinese are highest in VBD, followed by Malay and Indian. Multivariable analysis showed that increasing BMI and BFM were independent predictors of increased overall breast volume and dense volume. Moreover, BMI and BFM were independently and inversely related to VBD.

  19. Correlation between the extent of catalytic activity and charge density of montmorillonites.

    Science.gov (United States)

    Ertem, Gözen; Steudel, Annett; Emmerich, Katja; Lagaly, Gerhard; Schuhmann, Rainer

    2010-09-01

    The clay mineral montmorillonite is a member of the phyllosilicate group of minerals, which has been detected on martian soil. Montmorillonite catalyzes the condensation of activated monomers to form RNA-like oligomers. Extent of catalysis, that is, the yield of oligomers, and the length of the longest oligomer formed in these reactions widely varies with the source of montmorillonite (i.e., the locality where the mineral is mined). This study was undertaken to establish whether there exists a correlation between the extent of catalytic property and the charge density of montmorillonites. Charge density was determined by saturating the montmorillonites with alkyl ammonium cations that contained increasing lengths of alkyl chains, [CH₃-(CH₂)(n)-NH₃](+), where n = 3-16 and 18, and then measuring d(₀₀₁), interlayer spacing of the resulting montmorillonite-alkyl ammonium-montmorillonite complex by X-ray diffractometry (XRD). Results demonstrate that catalytic activity of montmorillonites with lower charge density is superior to that of higher charge density montmorillonite. They produce longer oligomers that contain 9 to 10 monomer units, while montmorillonite with high charge density catalyzes the formation of oligomers that contain only 4 monomer units. The charge density of montmorillonites can also be calculated from the chemical composition if elemental analysis data of the pure mineral are available. In the next mission to Mars, CheMin (Chemistry and Mineralogy), a combined X-ray diffraction/X-ray fluorescence instrument, will provide information on the mineralogical and elemental analysis of the samples. Possible significance of these results for planning the future missions to Mars for the search of organic compounds and extinct or extant life is discussed.

  20. Theoretical description of pump/probe experiments in electron-mediated charge-density-wave insulators

    Science.gov (United States)

    Freericks, J. K.; Matveev, O. P.; Shen, Wen; Shvaika, A. M.; Devereaux, T. P.

    2017-03-01

    In this review, we develop the formalism employed to describe charge-density-wave insulators in pump/probe experiments that use ultrashort driving pulses of light. The theory emphasizes exact results in the simplest model for a charge-density-wave insulator (given by a noninteracting system with two bands and a gap) and employs nonequilibrium dynamical mean-field theory to solve the Falicov-Kimball model in its ordered phase. We show how to develop the formalism and how the solutions behave. Care is taken to describe the details behind these calculations and to show how to verify their accuracy via sum-rule constraints.

  1. Interplay between the orbital quantization and Pauli effect in a charge-density-wave organic conductor

    Science.gov (United States)

    Kartsovnik, Mark; Andres, Dieter; Grigoriev, Pavel; Biberacher, Werner; Müller, Harald

    2004-04-01

    The interlayer magnetoresistance of the low-dimensional organic metal α-(BEDT-TTF) 2KHg(SCN) 4 under pressure shows features which are likely associated with theoretically predicted field-induced charge-density-wave (FICDW) transitions. At ambient pressure, a magnetic field strongly tilted towards the conducting layers induces a series of hysteretic anomalies. We attribute these anomalies to a novel kind of FICDW originating from a superposition of the orbital quantization of the nesting vector and Pauli effect on the charge-density wave.

  2. Orbital quantization in the high-magnetic-field state of a charge-density-wave system

    Science.gov (United States)

    Andres, D.; Kartsovnik, M. V.; Grigoriev, P. D.; Biberacher, W.; Müller, H.

    2003-11-01

    A superposition of the Pauli and orbital couplings of a high magnetic field to charge carriers in a charge-density-wave (CDW) system is proposed to give rise to transitions between subphases with quantized values of the CDW wave vector. By contrast to the purely orbital field-induced density-wave effects which require a strongly imperfect nesting of the Fermi surface, the new transitions can occur even if the Fermi surface is well nested at zero field. We suggest that such transitions are observed in the organic metal α-(BEDT-TTF)2KHg(SCN)4 under a strongly tilted magnetic field.

  3. Interplay between the orbital quantization and Pauli effect in a charge-density-wave organic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Kartsovnik, Mark; Andres, Dieter; Grigoriev, Pavel; Biberacher, Werner; Mueller, Harald

    2004-04-30

    The interlayer magnetoresistance of the low-dimensional organic metal {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} under pressure shows features which are likely associated with theoretically predicted field-induced charge-density-wave (FICDW) transitions. At ambient pressure, a magnetic field strongly tilted towards the conducting layers induces a series of hysteretic anomalies. We attribute these anomalies to a novel kind of FICDW originating from a superposition of the orbital quantization of the nesting vector and Pauli effect on the charge-density wave.

  4. Analysis of charge photogeneration as a key determinant of photocurrent density in polymer: fullerene solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Tracey M.; Shoaee, Safa; Soon, Ying W.; Durrant, James R. [Centre for Plastic Electronics, Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Ballantyne, Amy; Nelson, Jenny [Centre for Plastic Electronics, Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Duffy, Warren; Heeney, Martin; McCulloch, Iain [Centre for Plastic Electronics, Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Merck Chemicals, Chilworth Science Park, Southampton SO16 7QD (United Kingdom)

    2010-12-07

    Charge photogeneration: The correlation between the efficiency of photogeneration of dissociated polarons and photocurrent densities for organic solar cells based on polymer:fullerene blend films is investigated. Optical assays of polaron yield measured in films without electrodes show a remarkably clear correlation with short circuit density and quantum yield measured in complete devices. For the blend films studied herein, the primary determinant of photocurrent generation is the efficiency of dissociation of photogenerated charges away from the polymer/fullerene interface and the primary loss pathway is geminate recombination. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Quantum time crystal by decoherence: Proposal with an incommensurate charge density wave ring

    Science.gov (United States)

    Nakatsugawa, K.; Fujii, T.; Tanda, S.

    2017-09-01

    We show that time translation symmetry of a ring system with a macroscopic quantum ground state is broken by decoherence. In particular, we consider a ring-shaped incommensurate charge density wave (ICDW ring) threaded by a fluctuating magnetic flux: the Caldeira-Leggett model is used to model the fluctuating flux as a bath of harmonic oscillators. We show that the charge density expectation value of a quantized ICDW ring coupled to its environment oscillates periodically. The Hamiltonians considered in this model are time independent unlike "Floquet time crystals" considered recently. Our model forms a metastable quantum time crystal with a finite length in space and in time.

  6. Extension of many-body theory and approximate density functionals to fractional charges and fractional spins.

    Science.gov (United States)

    Yang, Weitao; Mori-Sánchez, Paula; Cohen, Aron J

    2013-09-14

    The exact conditions for density functionals and density matrix functionals in terms of fractional charges and fractional spins are known, and their violation in commonly used functionals has been shown to be the root of many major failures in practical applications. However, approximate functionals are designed for physical systems with integer charges and spins, not in terms of the fractional variables. Here we develop a general framework for extending approximate density functionals and many-electron theory to fractional-charge and fractional-spin systems. Our development allows for the fractional extension of any approximate theory that is a functional of G(0), the one-electron Green's function of the non-interacting reference system. The extension to fractional charge and fractional spin systems is based on the ensemble average of the basic variable, G(0). We demonstrate the fractional extension for the following theories: (1) any explicit functional of the one-electron density, such as the local density approximation and generalized gradient approximations; (2) any explicit functional of the one-electron density matrix of the non-interacting reference system, such as the exact exchange functional (or Hartree-Fock theory) and hybrid functionals; (3) many-body perturbation theory; and (4) random-phase approximations. A general rule for such an extension has also been derived through scaling the orbitals and should be useful for functionals where the link to the Green's function is not obvious. The development thus enables the examination of approximate theories against known exact conditions on the fractional variables and the analysis of their failures in chemical and physical applications in terms of violations of exact conditions of the energy functionals. The present work should facilitate the calculation of chemical potentials and fundamental bandgaps with approximate functionals and many-electron theories through the energy derivatives with respect to the

  7. Induced fermionic charge and current densities in two-dimensional rings

    CERN Document Server

    Bellucci, S; Grigoryan, A Kh

    2016-01-01

    For a massive quantum fermionic field, we investigate the vacuum expectation values (VEVs) of the charge and current densities induced by an external magnetic flux in a two-dimensional circular ring. Both the irreducible representations of the Clifford algebra are considered. On the ring edges the bag (infinite mass) boundary conditions are imposed for the field operator. This leads to the Casimir type effect on the vacuum characteristics. The radial current vanishes. The charge and the azimuthal current are decomposed into the boundary-free and boundary-induced contributions. Both these contributions are odd periodic functions of the magnetic flux with the period equal to the flux quantum. An important feature that distinguishes the VEVs of the charge and current densities from the VEV of the energy density, is their finiteness on the ring edges. The current density is equal to the charge density for the outer edge and has the opposite sign on the inner edge. The VEVs are peaked near the inner edge and, as f...

  8. Spatially separated charge densities of electrons and holes in organic-inorganic halide perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dan; Liang, Chunjun, E-mail: chjliang@bjtu.edu.cn, E-mail: zhqhe@bjtu.edu.cn; Zhang, Huimin; You, Fangtian; He, Zhiqun, E-mail: chjliang@bjtu.edu.cn, E-mail: zhqhe@bjtu.edu.cn [Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Chunxiu [Information Recording Materials Lab, Beijing Institute of Graphic Communication, Beijing 102600 (China)

    2015-02-21

    Solution-processable methylammonium lead trihalide perovskites exhibit remarkable high-absorption and low-loss properties for solar energy conversion. Calculation from density functional theory indicates the presence of non-equivalent halogen atoms in the unit cell because of the specific orientation of the organic cation. Considering the 〈100〉 orientation as an example, I{sub 1}, one of the halogen atoms, differs from the other iodine atoms (I{sub 2} and I{sub 3}) in terms of its interaction with the organic cation. The valance-band-maximum (VBM) and conduction-band-minimum (CBM) states are derived mainly from 5p orbital of I{sub 1} atom and 6p orbital of Pb atom, respectively. The spatially separated charge densities of the electrons and holes justify the low recombination rate of the pure iodide perovskite. Chlorine substitution further strengthens the unique position of the I{sub 1} atom, leading to more localized charge density around the I{sub 1} atom and less charge density around the other atoms at the VBM state. The less overlap of charge densities between the VBM and CBM states explains the relatively lower carrier recombination rate of the iodine-chlorine mixed perovskite. Chlorine substitution significantly reduces the effective mass at a direction perpendicular to the Pb-Cl bond and organic axis, enhancing the carrier transport property of the mixed perovskite in this direction.

  9. Spatially separated charge densities of electrons and holes in organic-inorganic halide perovskites

    Science.gov (United States)

    Li, Dan; Liang, Chunjun; Zhang, Huimin; Zhang, Chunxiu; You, Fangtian; He, Zhiqun

    2015-02-01

    Solution-processable methylammonium lead trihalide perovskites exhibit remarkable high-absorption and low-loss properties for solar energy conversion. Calculation from density functional theory indicates the presence of non-equivalent halogen atoms in the unit cell because of the specific orientation of the organic cation. Considering the orientation as an example, I1, one of the halogen atoms, differs from the other iodine atoms (I2 and I3) in terms of its interaction with the organic cation. The valance-band-maximum (VBM) and conduction-band-minimum (CBM) states are derived mainly from 5p orbital of I1 atom and 6p orbital of Pb atom, respectively. The spatially separated charge densities of the electrons and holes justify the low recombination rate of the pure iodide perovskite. Chlorine substitution further strengthens the unique position of the I1 atom, leading to more localized charge density around the I1 atom and less charge density around the other atoms at the VBM state. The less overlap of charge densities between the VBM and CBM states explains the relatively lower carrier recombination rate of the iodine-chlorine mixed perovskite. Chlorine substitution significantly reduces the effective mass at a direction perpendicular to the Pb-Cl bond and organic axis, enhancing the carrier transport property of the mixed perovskite in this direction.

  10. Density decrease in vanadium-base alloys irradiated in the dynamic helium charging experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Galvin, T.M.; Smith, D.L. [Argonne National Laboratory, Chicago, IL (United States)

    1996-04-01

    Combined effects of dynamically charged helium and neutron damage on density decrease (swelling) of V-4Cr-4Ti, V-5Ti, V-3Ti-1Si, and V-8Cr-6Ti alloys have been determined after irradiation to 18-31 dpa at 425-600{degrees}C in the Dynamic helium Charging Experiment (DHCE). To ensure better accuracy in density measurement, broken pieces of tensile specimens {approx} 10 times heavier than a transmission electron microscopy (TEM) disk were used. Density increases of the four alloys irradiated in the DHCE were <0.5%. This small change seems to be consistent with the negligible number density of microcavities characterized by TEM. Most of the dynamically produced helium atoms seem to have been trapped in the grain matrix without significant cavity nucleation or growth.

  11. Spin and charge distribution in iron porphyrin models: a coupled cluster and density-functional study.

    Science.gov (United States)

    Johansson, Mikael P; Sundholm, Dage

    2004-02-15

    We recently performed detailed analyses of the electronic structure of low-spin iron porphyrins using density-functional theory (DFT). Both the spin-density distributions of the oxidized, ferric forms, as well as the changes in total charge density upon reduction to the ferrous forms have been explored. Here, we compare the DFT results with wave-function theory, more specifically, with the approximate singles and doubles coupled-cluster method (CC2). Different spin states are considered by studying representative models of low spin, intermediate spin, and high spin species. The CC2 calculations corroborate the DFT results; the spin density exhibits the same amount of molecular spin polarization, and the charge delocalization is of comparable magnitude. Slight differences in the descriptions are noted and discussed.

  12. Effects of casein, whey and soy proteins on volumetric bone density and bone strength in immunocompromised piglets

    DEFF Research Database (Denmark)

    Budek, Alicja Zofia; Bjørnvad, Charlotte; Mølgaard, Christian

    2007-01-01

    assigned to a formula based on either casein (n=11), whey (n=11) or soy (n=10) as the protein source (each 55 g/L), and equal amounts of fat, carbohydrates, calcium and phosphorus. Results & Conclusion: Despite efforts to sustain immuno-protection (sow serum and antibiotic injections), some piglets became......Summary:Background and aims: Bone-promoting effect of different proteins in early life, under immunocompromised conditions, is unknown. We investigated effects of milk- and plantderived proteins on bone development in immunocompromised piglets. Methods: Newborn, colostrum-deprived piglets were...... sick and were early euthanised. After 6 days, bone density (peripheral quantitative computed tomography), bone mechanical strength (three-point bending test) and serum insulin-like growth factor-I (sIGF-I) (immunoassay) were measured in the surviving piglets (casein n=5, whey n=9, soy n=5)....

  13. Charged impurity scattering limited low temperature resistivity of low density silicon inversion layers

    OpenAIRE

    Sarma, S. Das; Hwang, E. H.

    1998-01-01

    We calculate within the Boltzmann equation approach the charged impurity scattering limited low temperature electronic resistivity of low density $n$-type inversion layers in Si MOSFET structures. We find a rather sharp quantum to classical crossover in the transport behavior in the $0 - 5$K temperature range, with the low density, low temperature mobility showing a strikingly strong non-monotonic temperature dependence, which may qualitatively explain the recently observed anomalously strong...

  14. Finite temperature fermion condensate, charge and current densities in a (2+1)-dimensional conical space

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, S. [INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Bezerra de Mello, E.R. [Universidade Federal da Parai ba, Departamento de Fisica, 58.059-970, Joao Pessoa, PB (Brazil); Braganca, E. [INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Universidade Federal da Parai ba, Departamento de Fisica, 58.059-970, Joao Pessoa, PB (Brazil); Saharian, A.A. [Yerevan State University, Department of Physics, Yerevan (Armenia)

    2016-06-15

    We evaluate the fermion condensate and the expectation values of the charge and current densities for a massive fermionic field in (2+1)-dimensional conical spacetime with a magnetic flux located at the cone apex. The consideration is done for both irreducible representations of the Clifford algebra. The expectation values are decomposed into the vacuum expectation values and contributions coming from particles and antiparticles. All these contributions are periodic functions of the magnetic flux with the period equal to the flux quantum. Related to the non-invariance of the model under the parity and time-reversal transformations, the fermion condensate and the charge density have indefinite parity with respect to the change of the signs of the magnetic flux and chemical potential. The expectation value of the radial current density vanishes. The azimuthal current density is the same for both the irreducible representations of the Clifford algebra. It is an odd function of the magnetic flux and an even function of the chemical potential. The behavior of the expectation values in various asymptotic regions of the parameters are discussed in detail. In particular, we show that for points near the cone apex the vacuum parts dominate. For a massless field with zero chemical potential the fermion condensate and charge density vanish. Simple expressions are derived for the part in the total charge induced by the planar angle deficit and magnetic flux. Combining the results for separate irreducible representations, we also consider the fermion condensate, charge and current densities in parity and time-reversal symmetric models. Possible applications to graphitic nanocones are discussed. (orig.)

  15. Waveform measurement of charge- and spin-density wavepackets in a chiral Tomonaga-Luttinger liquid

    Science.gov (United States)

    Hashisaka, M.; Hiyama, N.; Akiho, T.; Muraki, K.; Fujisawa, T.

    2017-06-01

    In contrast to a free-electron system, a Tomonaga-Luttinger (TL) liquid in a one-dimensional (1D) electron system hosts charge and spin excitations as independent entities. When an electron is injected into a TL liquid, it transforms into charge- and spin-density wavepackets that propagate at different group velocities and move away from each other. This process, known as spin-charge separation, is the hallmark of TL physics. While spin-charge separation has been probed in momentum- or frequency-domain measurements in various 1D systems, waveforms of separated excitations, which are a direct manifestation of the TL behaviour, have been long awaited to be measured. Here, we present a waveform measurement for the pseudospin-charge separation process in a chiral TL liquid comprising quantum Hall edge channels. The charge- and pseudospin-density waveforms are captured by utilizing a spin-resolved sampling scope that records the spin-up or -down component of the excitations. This experimental technique provides full information for time evolution of the 1D electron system, including not only propagation of TL eigenmodes but also their decay in a practical device.

  16. Resonant soft x-ray scattering and charge density waves in correlated systems

    NARCIS (Netherlands)

    Rusydi, Andrivo

    2006-01-01

    Summary This work describes results obtained on the study of charge density waves (CDW) in strongly correlated systems with a new experimental method: resonant soft x-ray scattering (RSXS). The basic motivation is the 1986 discovery by Bednorz and Müler of a new type of superconductor, based on Cu a

  17. Electrical transport through constrictions in the charge-density wave conductor NbSe3

    NARCIS (Netherlands)

    O´Neill, K.; Slot, E.; Thorne, R.; Van der Zant, H.

    2005-01-01

    We have investigated the electrical transport properties of insulating and metallic constrictions of dimensions 100nm-10_m in the charge-density wave (CDW) conductor NbSe3. The constrictions are made in a variety of ways: focused ion beam, reactive ion etching through a resist mask, and in a mechani

  18. first-principle calculation of electrons charge density in the diamond ...

    African Journals Online (AJOL)

    DR. AMINU

    In a typical modern electronic structure calculation, the charge density is obtained from a certain ... normalized Slater atomic orbital for multi-electron atoms and ions. Since the spherical .... are used as a first approximation (John and Stefan, 2003). 124 ..... Dalton, and Thomas R. Kochler (Plenum Press, New. York) p. 183.

  19. Scanning tunneling microscopy in TTF-TCNQ: Phase and amplitude modulated charge density waves

    DEFF Research Database (Denmark)

    Wang, Z.Z.; Gorard, J.C.; Pasquier, C.

    2003-01-01

    Charge density waves (CDWs) have been studied at the surface of a cleaved tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) single crystal using a low temperature scanning tunneling microscope (STM) under ultrahigh-vacuum conditions, between 300 and 33 K with molecular resolution. All CDW...

  20. Full charge-density calculation of the surface energy of metals

    DEFF Research Database (Denmark)

    Vitos, Levente; Kollár, J..; Skriver, Hans Lomholt

    1994-01-01

    of the linear-muffin-tin-orbitals (LMTO) method and the ASA in surface calculations. We find that the full charge-density functional improves the agreement with recent full-potential LMTO calculations to a level where the average deviation in surface energy over the 4d series is down to 10%....

  1. THEORY OF THE THRESHOLD FIELD FOR THE DEPINNING TRANSITION OF A CHARGE-DENSITY WAVE

    NARCIS (Netherlands)

    PIETRONERO, L; VERSTEEG, M

    1991-01-01

    The Hamiltonian of an elastic string pinned by random potentials is often used to describe the depinning transition of a charge density wave in the presence of impurity pinning. The properties of the pinned states show close analogies to those of glassy systems, while the depinning transition resemb

  2. Resonant soft x-ray scattering and charge density waves in correlated systems

    NARCIS (Netherlands)

    Rusydi, Andrivo

    2006-01-01

    Summary This work describes results obtained on the study of charge density waves (CDW) in strongly correlated systems with a new experimental method: resonant soft x-ray scattering (RSXS). The basic motivation is the 1986 discovery by Bednorz and Müler of a new type of superconductor, based on Cu

  3. Reversible Electrochemical Sensor for Detection of High-Charge Density Polyanion Contaminants in Heparin.

    Science.gov (United States)

    Lester, Jacob; Chandler, Timothy; Gemene, Kebede L

    2015-11-17

    We present a simple, rapid, and inexpensive electrochemical sensor based on a reversible pulsed chronopotentiometric polyanion-selective membrane electrode for the detection and quantification of oversulfated chondroitin sulfate (OSCS) and other high charge-density polyanions that could potentially be used to adulterate heparin. The membrane is free of ion exchanger and is formulated with plasticized poly(vinyl chloride) (PVC) and an inert lipophilic salt, tridodecylmethylammonium-dinonylnaphthaline sulfonate (TDMA-DNNS). The neutral salt is used to reduce membrane resistance and to ensure reversibility of the sensor. More importantly, TDMA(+) is used as the recognition element for the polyanions. Here an anodic galvanostatic current pulse is applied across the membrane to cause the extraction of the polyanions from the sample into the membrane and potential is measured at the sample-membrane interface. The measured electromotive force (emf) is proportional to the concentration and the charge density of the polyanions. High charge-density polyanion contaminants and impurities in heparin can be detected using this method since the overall equilibrium potential response of polyions increases with increasing charge density of the polyions. Here, first the potential response of pure heparin is measured at a saturation concentration, the concentration beyond which further addition of heparin does not produce a change in potential response. Then the potential response of heparin tainted with different quantities of the high charge-density contaminant is measured at a fixed total polyion concentration (heparin concentration + contaminant concentration). The latter gives a greater negative potential response due to the presence of the high charge-density contaminant. The increase in the negative potential response can be used for detection and quantification of high charge-density contaminants in heparin. We demonstrate here that 0.3% (w/w) OSCS as well as 0.1% (w

  4. Molecular electronegativity in density functional theory(Ⅷ) Charge polarization modes in a closed system

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the density functional theory and the atom-bond electronegativity equalization model (ABEEM), a method is proposed to construct the softness matrix and to obtain the electron population normal modes (PNMs) for a closed system. Using this method the information about the bond charge polarization in a molecule can be obtained easily. The test calculation shows that the PNM obtained by this method includes all the modes about the bond charge polarization explicitly. And the bond charge polarization mode characterized by the biggest eigenvalue, which is the softest one of all modes related with chemical bonds, can describe the charge polarization process in a molecule as exquisitely as the corresponding ab initio method.

  5. Modeling noncovalent radical-molecule interactions using conventional density-functional theory: beware erroneous charge transfer.

    Science.gov (United States)

    Johnson, Erin R; Salamone, Michela; Bietti, Massimo; DiLabio, Gino A

    2013-02-07

    Conventional density-functional theory (DFT) has the potential to overbind radical-molecule complexes because of erroneous charge transfer. We examined this behavior by exploring the ability of various DFT approximations to predict fractional charge transfer and by quantifying the overbinding in a series of complexes. It is demonstrated that too much charge is transferred from molecules to radicals when the radical singly unoccupied molecular orbitals are predicted to be erroneously too low in energy relative to the molecule highest occupied molecular orbitals, leading to excessive Coulombic attraction. In this respect, DFT methods formulated with little or no Hartree-Fock exchange perform most poorly. The present results illustrate that the charge-transfer problem is much broader than may have been previously expected and is not limited to conventional (i.e., molecule-molecule) donor-acceptor complexes.

  6. The influence of oxidation on space charge formation in gamma-irradiated low-density polyethylene

    CERN Document Server

    Chen, G; Xie, H K; Banford, H M; Davies, A E

    2003-01-01

    The research presented in this paper investigates the role of oxidation in the formation of space charge in gamma-irradiated low-density polyethylene after being electrically stressed under dc voltage. Polyethylene plaques both with and without antioxidant were irradiated up to 500 kGy using a sup 6 sup 0 Co gamma source and space charge distributions were measured using the piezoelectric induced pressure wave propagation method. It has been found that a large amount of positive charge evolved adjacent to the cathode in the sample without antioxidant and was clearly associated with oxidation of the surface. The amount of charge formed for a given applied stress increased with the dose absorbed by the material. A model has been proposed to explain the formation of space charge and its profile. The charge decay after the removal of the external applied stress is dominated by a process being controlled by the cathode interfacial stress (charge injection) rather than a conventional RC circuit model. On the other ...

  7. Quantifying the nucleon’s pion cloud with transverse charge densities

    Energy Technology Data Exchange (ETDEWEB)

    Strikman, M.; Weiss, C.

    2010-10-01

    The transverse densities in a fast-moving nucleon offer a model-independent framework for analyzing the spatial structure of the pion cloud and its role in current matrix elements. We calculate the chiral large-distance component of the charge density in a dispersion representation of the form factor and discuss its partonic interpretation. It dominates over the nonchiral density only at surprisingly large distances above ~2 fm. The chiral component can be probed in precision low-Q^2 elastic eN scattering or in peripheral deep-inelastic processes that resolve its quark/gluon content.

  8. Experimental charge density of hematite in its magnetic low temperature and high temperature phases.

    Science.gov (United States)

    Theissmann, R; Fuess, H; Tsuda, K

    2012-09-01

    Structural parameters of hematite (α-Fe(2)O(3)), including the valence electron distribution, were investigated using convergent beam electron diffraction (CBED) in the canted antiferromagnetic phase at room temperature and in the collinear antiferromagnetic phase at 90K. The refined charge density maps are interpreted as a direct result of electron-electron interaction in a correlated system. A negative deformation density was observed as a consequence of closed shell interaction. Positive deformation densities are interpreted as a shift of electron density to antibinding molecular orbitals. Following this interpretation, the collinear antiferromagnetic phase shows the characteristic of a Mott-Hubbard type insulator whereas the high temperature canted antiferromagnetic phase shows the characteristic of a charge transfer insulator. The break of the threefold symmetry in the canted antiferromagnetic phase was correlated to the presence of oxygen-oxygen bonding, which is caused by a shift of spin polarized charge density from iron 3d-orbitals to the oxygen ions. We propose a triangular magnetic coupling in the oxygen planes causing a frustrated triangular spin arrangement with all spins lying in the oxygen planes. This frustrated arrangement polarizes the super-exchange between iron ions and causes the spins located at the iron ions to orient in the same plane, perpendicular to the threefold axis. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Electrostatic force density for a scanned probe above a charged surface

    Energy Technology Data Exchange (ETDEWEB)

    Passian, A.; Wig, A.; Meriaudeau, F.; Buncick, M.; Thundat, T.; Ferrell, T. L.

    2001-07-15

    The Coulomb interaction of a dielectric probe tip with a uniform field existing above a semi-infinite, homogeneous dielectric substrate is studied. The induced polarization surface charge density and the field distribution at the bounding surface of the dielectric medium with the geometry of half of a two sheeted hyperboloid of revolution located above the dielectric half space interfaced with a uniform surface charge density is calculated. The force density on the hyperboloidal probe medium is calculated as a function of the probe tip shape. The calculation is based on solving Laplace's equation and employing a newly derived integral expansion for the vanishing dielectric limit of the potential. The involved numerical simulations comprise the evaluation of infinite double integrals involving conical functions.

  10. Electrostatic force density for a scanned probe above a charged surface

    Science.gov (United States)

    Passian, A.; Wig, A.; Meriaudeau, F.; Buncick, M.; Thundat, T.; Ferrell, T. L.

    2001-07-01

    The Coulomb interaction of a dielectric probe tip with a uniform field existing above a semi-infinite, homogeneous dielectric substrate is studied. The induced polarization surface charge density and the field distribution at the bounding surface of the dielectric medium with the geometry of half of a two sheeted hyperboloid of revolution located above the dielectric half space interfaced with a uniform surface charge density is calculated. The force density on the hyperboloidal probe medium is calculated as a function of the probe tip shape. The calculation is based on solving Laplace's equation and employing a newly derived integral expansion for the vanishing dielectric limit of the potential. The involved numerical simulations comprise the evaluation of infinite double integrals involving conical functions.

  11. Transverse charge and magnetization densities in the nucleon's chiral periphery

    Energy Technology Data Exchange (ETDEWEB)

    Granados, Carlos G. [JLAB Newport News, VA (United States); Weiss, Christian [JLAB Newport News, VA (United States)

    2014-01-01

    In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances b = O(M{pi}{sup -1}), where they are governed by universal chiral dynamics and can be computed in a model-independent manner. Of particular interest is the comparison of the peripheral charge and magnetization densities. We summarize (a) their interpretation as spin-independent and -dependent current matrix elements; (b) the leading-order chiral effective field theory results; (c) their mechanical interpretation in the light-front formulation; (d) the large-N_c limit of QCD and the role of {Delta} intermediate states; (e) the connection with generalized parton distributions and peripheral high-energy scattering processes.

  12. Immobilization of bilirubin oxidase on graphene oxide flakes with different negative charge density for oxygen reduction. The effect of GO charge density on enzyme coverage, electron transfer rate and current density.

    Science.gov (United States)

    Filip, Jaroslav; Andicsová-Eckstein, Anita; Vikartovská, Alica; Tkac, Jan

    2017-03-15

    Previously we showed that an effective bilirubin oxidase (BOD)-based biocathode using graphene oxide (GO) could be prepared in 2 steps: 1. electrostatic adsorption of BOD on GO; 2. electrochemical reduction of the BOD-GO composite to form a BOD-ErGO (electrochemically reduced GO) film on the electrode. In order to identify an optimal charge density of GO for BOD-ErGO composite preparation, several GO fractions differing in an average flake size and ζ-potential were prepared using centrifugation and consequently employed for BOD-ErGO biocathode preparation. A simple way to express surface charge density of these particular GO nanosheets was developed. The values obtained were then correlated with biocatalytic and electrochemical parameters of the prepared biocathodes, i.e. electrocatalytically active BOD surface coverage (Γ), heterogeneous electron transfer rate (kS) and a maximum biocatalytic current density. The highest bioelectrocatalytic current density of (597±25)μAcm(-2) and the highest Γ of (23.6±0.9)pmolcm(-2) were obtained on BOD-GO composite having the same moderate negative charge density, but the highest kS of (79.4±4.6)s(-1) was observed on BOD-GO composite having different negative charge density. This study is a solid foundation for others to consider the influence of a charge density of GO on direct bioelectrochemistry/bioelectrocatalysis of other redox enzymes applicable for construction of biosensors, bioanodes, biocathodes or biofuel cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Investigation of surface charge density on solid-liquid interfaces by modulating the electrical double layer.

    Science.gov (United States)

    Moon, Jong Kyun; Song, Myung Won; Pak, Hyuk Kyu

    2015-05-20

    A solid surface in contact with water or aqueous solution usually carries specific electric charges. These surface charges attract counter ions from the liquid side. Since the geometry of opposite charge distribution parallel to the solid-liquid interface is similar to that of a capacitor, it is called an electrical double layer capacitor (EDLC). Therefore, there is an electrical potential difference across an EDLC in equilibrium. When a liquid bridge is formed between two conducting plates, the system behaves as two serially connected EDLCs. In this work, we propose a new method for investigating the surface charge density on solid-liquid interfaces. By mechanically modulating the electrical double layers and simultaneously applying a dc bias voltage across the plates, an ac electric current can be generated. By measuring the voltage drop across a load resistor as a function of bias voltage, we can study the surface charge density on solid-liquid interfaces. Our experimental results agree very well with the simple equivalent electrical circuit model proposed here. Furthermore, using this method, one can determine the polarity of the adsorbed state on the solid surface depending on the material used. We expect this method to aid in the study of electrical phenomena on solid-liquid interfaces.

  14. Relationships between atmospheric positive electric charge densities and gas bubble concentrations in the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Zygmunt Klusek

    2004-12-01

    Full Text Available Simultaneous measurements of bubble density in the sea subsurface and positive ions in the lower atmosphere were performed in the Baltic Sea in the summer of 1999. Bubbles in two size ranges, around 27 and 100 µm, were measured acoustically. Airborne positive charge was measured with a Gerdien instrument. Observed concentrations of air ions varied from 60 cm-3 up to 600 cm-3.      The relative role of bubbles and wind speed on the positive air ion concentrations over the brackish water of the Baltic Sea is discussed. The parameters of a model of a log-log dependence between charge concentration and bubble density are calculated.      The correlation functions between time series of concentrations of positive charges over the sea and gas bubbles averaged over a depth range from 0.4 to 4 m and wind speed are presented. There was zero lag between the cross-correlation maxima of charge and bubbles, but there was a phase lag of one and a half hours between charge and wind speed.

  15. Fractional-charge and fractional-spin errors in range-separated density-functional theory

    CERN Document Server

    Mussard, Bastien

    2016-01-01

    We investigate fractional-charge and fractional-spin errors in range-separated density-functional theory. Specifically, we consider the range-separated hybrid (RSH) method which combines long-range Hartree-Fock (HF) exchange with a short-range semilocal exchange-correlation density functional, and the RSH+MP2 method which adds long-range second-order M{{\\o}}ller-Plesset (MP2) correlation. Results on atoms and molecules show that the fractional-charge errors obtained in RSH are much smaller than in the standard Kohn-Sham (KS) scheme applied with semilocal or hybrid approximations, and also generally smaller than in the standard HF method. The RSH+MP2 method tends to have smaller fractional-charge errors than standard MP2 for the most diffuse systems, but larger fractional-charge errors for the more compact systems. Even though the individual contributions to the fractional-spin errors in the H atom coming from the short-range exchange and correlation density-functional approximations are smaller than the corre...

  16. Toward a global description of nuclear charge radii: Exploring the Fayans energy density functional

    Science.gov (United States)

    Reinhard, P.-G.; Nazarewicz, W.

    2017-06-01

    Background: Binding energies and charge radii are fundamental properties of atomic nuclei. When inspecting their particle-number dependence, both quantities exhibit pronounced odd-even staggering. While the odd-even effect in binding energy can be attributed to nucleonic pairing, the origin of staggering in charge radii is less straightforward to ascertain. Purpose: In this work, we study the odd-even effect in binding energies and charge radii, and systematic behavior of differential radii, to identify the underlying components of the effective nuclear interaction. Method: We apply nuclear density functional theory using a family of Fayans and Skyrme energy density functionals fitted to similar data sets but using different optimization protocols. We inspect various correlations between differential charge radii, odd-even staggering in energies and radii, and nuclear matter properties. The Fayans functional is assumed to be in the local FaNDF0 form. Detailed analysis is carried out for medium-mass and heavy semimagic nuclei with a particular focus on the Ca chain. Results: By making the surface and pairing terms dependent on density gradients, the Fayans functional offers the superb simultaneous description of odd-even staggering effects in energies and charge radii. Conversely, when the data on differential radii are added to the pool of fit observables, the coupling constants determining the strengths of the gradient terms of Fayans functional are increased by orders of magnitude. The Skyrme functional optimized in this work with the generalized Fayans pairing term offers results of similar quality. We quantify these findings by performing correlation analysis based on the statistical linear regression technique. The nuclear matter parameters characterizing Fayans and Skyrme functionals optimized to similar data sets are fairly close. Conclusion: The Fayans paring functional, with its generalized density dependence, significantly improves the description of

  17. Comparison of the Volume Charge Density of Nanofiltration Membranes Obtained from Retention and Conductivity Experiments

    DEFF Research Database (Denmark)

    Benavente, J.; Silva, V.; Pradanos, P.

    2010-01-01

    A version of the Donnan steric-partitioning pore model with dielectrical exclusion (DSPM-DE) has been used to get information on the pore size and charge density of a commercial membrane, NF45 from FilmTec, from its retention of KCl solutions. The conductivity inside the pores has been measured...... of the membrane. These two methods give results in fair accordance which probes that the sometimes controversial method of DSPM-DE can give accurate results for the charge as well as for the mean pore size of a nanofiltration membrane. Sonic clues to improve the way this model can be used are given as well....

  18. The generalization of charged AdS black hole specific volume and number density

    Science.gov (United States)

    Wang, Zi-Liang; He, Miao; Fang, Chao; Sun, Dao-Quan; Deng, Jian-Bo

    2017-04-01

    In this paper, by proposing a generalized specific volume, we restudy the P- V criticality of charged AdS black holes in the extended phase space. The results show that most of the previous conclusions can be generalized without change, but the ratio {\\tilde{ρ }}_c should be 3 {\\tilde{α }}/16 in general case. Further research on the thermodynamical phase transition of black hole leads us to a natural interpretation of our assumption, and more black hole properties can be generalized. Finally, we study the number density for charged AdS black hole in higher dimensions, the results show the necessity of our assumption.

  19. Electrostatic solvation free energies of charged hard spheres using molecular dynamics with density functional theory interactions

    Science.gov (United States)

    Duignan, Timothy T.; Baer, Marcel D.; Schenter, Gregory K.; Mundy, Chistopher J.

    2017-10-01

    Determining the solvation free energies of single ions in water is one of the most fundamental problems in physical chemistry and yet many unresolved questions remain. In particular, the ability to decompose the solvation free energy into simple and intuitive contributions will have important implications for models of electrolyte solution. Here, we provide definitions of the various types of single ion solvation free energies based on different simulation protocols. We calculate solvation free energies of charged hard spheres using density functional theory interaction potentials with molecular dynamics simulation and isolate the effects of charge and cavitation, comparing to the Born (linear response) model. We show that using uncorrected Ewald summation leads to unphysical values for the single ion solvation free energy and that charging free energies for cations are approximately linear as a function of charge but that there is a small non-linearity for small anions. The charge hydration asymmetry for hard spheres, determined with quantum mechanics, is much larger than for the analogous real ions. This suggests that real ions, particularly anions, are significantly more complex than simple charged hard spheres, a commonly employed representation.

  20. Static and Dynamical Valence-Charge-Density Properties of GaAs

    Science.gov (United States)

    Pietsch, Ullrich

    1993-02-01

    Owing to the close neighbourhood of Ga and As in Mendeleev's table, GaAs shows two fundamental classes of X-ray structure amplitudes distinguished by their extremely different scattering power. They are differently sensitive to the valence electron density (VED) redistribution caused by the chemical bond and must be measured by different experimental methods. Using such data, both the VED and the difference electron densities (DED) are calculated here. Comparison with theoret-ical densities shows that the VED is characterized by covalent, ionic and metallic contributions. The DED constructed from GaAs and Ge data demonstrates the electronic response caused by a "protonic" charge transfer between both f.c.c. sublattices as well as the transition from a purely covalent to a mixed covalent-ionic bond. Especially the charge-density accumulation between nearest neighbours (bond charge (BC)) depends on the distance between the bonding atoms and changes under the influence of any lattice deformation. This phenomenon is described by a BC-transfer model. Its direct experimental proof is given by measuring the variation of the scattering power of weak reflections under the influence of an external electric field. This experiment demonstrates that the ionicity of the bond changes in addition to the BC variation.

  1. Charge Density Analysis and Transport Properties of TTF Based Molecular Nanowires: A DFT Approach

    Directory of Open Access Journals (Sweden)

    Karuppannan Selvaraju

    2015-01-01

    Full Text Available The present study has been performed to understand the charge density distribution and the electrical characteristics of Au and thiol substituted tetrathiafulvalene (TTF based molecular nanowire. A quantum chemical calculation has been carried out using DFT method (B3LYP with the LANL2DZ basis set under various applied electric fields (EFs. The bond topological analysis characterizes the terminal Au–S and S–C bonds as well as all the bonds of central TTF unit of the molecule. The variation of electron density and Laplacian of electron density at the bond critical point of bonds for zero and different applied fields reveal the electron density distribution of the molecule. The molecular conformation, the variation of atomic charges and energy density distribution of the molecule have been analyzed for the various levels of applied EFs. The HOMO-LUMO gap calculated from quantum chemical calculations has been compared with the value calculated from the density of states. The variation of dipole moment due to the polarization effect and the I-V characteristics of the molecule for the various applied EFs have been well discussed.

  2. Charge-density analysis using multipolar atom and spherical charge models: 2-methyl-1,3-cyclopentanedione, a compound displaying a resonance-assisted hydrogen bond.

    Science.gov (United States)

    Nassour, Ayoub; Kubicki, Maciej; Wright, Jonathan; Borowiak, Teresa; Dutkiewicz, Grzegorz; Lecomte, Claude; Jelsch, Christian

    2014-04-01

    The experimental charge-density distribution in 2-methyl-1,3-cyclopentanedione in the crystal state was analyzed by synchrotron X-ray diffraction data collection at 0.33 Å resolution. The molecule in the crystal is in the enol form. The experimental electron density was refined using the Hansen-Coppens multipolar model and an alternative modeling, based on spherical atoms and additional charges on the covalent bonds and electron lone-pair sites. The crystallographic refinements, charge-density distributions, molecular electrostatic potentials, dipole moments and intermolecular interaction energies obtained from the different charge-density models were compared. The experimental results are also compared with the theoretical charge densities using theoretical structure factors obtained from periodic quantum calculations at the B3LYP/6-31G** level. A strong intermolecular O-H···O hydrogen bond connects molecules along the [001] direction. The deformation density maps show the resonance within the O=C-C=C-OH fragment and merged lone pair lobes on the hydroxyl O atom. This resonance is further confirmed by the analysis of charges and topology of the electron density.

  3. Ultrahigh volumetric capacitance and cyclic stability of fluorine and nitrogen co-doped carbon microspheres

    Science.gov (United States)

    Zhou, Junshuang; Lian, Jie; Hou, Li; Zhang, Junchuan; Gou, Huiyang; Xia, Meirong; Zhao, Yufeng; Strobel, Timothy A.; Tao, Lu; Gao, Faming

    2015-09-01

    Highly porous nanostructures with large surface areas are typically employed for electrical double-layer capacitors to improve gravimetric energy storage capacity; however, high surface area carbon-based electrodes result in poor volumetric capacitance because of the low packing density of porous materials. Here, we demonstrate ultrahigh volumetric capacitance of 521 F cm-3 in aqueous electrolytes for non-porous carbon microsphere electrodes co-doped with fluorine and nitrogen synthesized by low-temperature solvothermal route, rivaling expensive RuO2 or MnO2 pseudo-capacitors. The new electrodes also exhibit excellent cyclic stability without capacitance loss after 10,000 cycles in both acidic and basic electrolytes at a high charge current of 5 A g-1. This work provides a new approach for designing high-performance electrodes with exceptional volumetric capacitance with high mass loadings and charge rates for long-lived electrochemical energy storage systems.

  4. Influence of the overall charge and local charge density of pectin on the complex formation between pectin and beta-lactoglobulin

    NARCIS (Netherlands)

    Sperber, Bram L. H. M.; Schols, Henk A.; Stuart, Martien A. Cohen; Norde, Willem; Voragen, Alphons G. J.

    2009-01-01

    The complex formation between beta-lactoglobulin (beta-lg) and pectin is studied using pectins with different physicochemical characteristics. Pectin allows for the control of both the overall charge by degree of methyl-esterification as well as local charge density by the degree of blockiness. Vary

  5. Automated fibroglandular tissue segmentation and volumetric density estimation in breast MRI using an atlas-aided fuzzy C-means method

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shandong; Weinstein, Susan P.; Conant, Emily F.; Kontos, Despina, E-mail: despina.kontos@uphs.upenn.edu [Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2013-12-15

    Purpose: Breast magnetic resonance imaging (MRI) plays an important role in the clinical management of breast cancer. Studies suggest that the relative amount of fibroglandular (i.e., dense) tissue in the breast as quantified in MR images can be predictive of the risk for developing breast cancer, especially for high-risk women. Automated segmentation of the fibroglandular tissue and volumetric density estimation in breast MRI could therefore be useful for breast cancer risk assessment. Methods: In this work the authors develop and validate a fully automated segmentation algorithm, namely, an atlas-aided fuzzy C-means (FCM-Atlas) method, to estimate the volumetric amount of fibroglandular tissue in breast MRI. The FCM-Atlas is a 2D segmentation method working on a slice-by-slice basis. FCM clustering is first applied to the intensity space of each 2D MR slice to produce an initial voxelwise likelihood map of fibroglandular tissue. Then a prior learned fibroglandular tissue likelihood atlas is incorporated to refine the initial FCM likelihood map to achieve enhanced segmentation, from which the absolute volume of the fibroglandular tissue (|FGT|) and the relative amount (i.e., percentage) of the |FGT| relative to the whole breast volume (FGT%) are computed. The authors' method is evaluated by a representative dataset of 60 3D bilateral breast MRI scans (120 breasts) that span the full breast density range of the American College of Radiology Breast Imaging Reporting and Data System. The automated segmentation is compared to manual segmentation obtained by two experienced breast imaging radiologists. Segmentation performance is assessed by linear regression, Pearson's correlation coefficients, Student's pairedt-test, and Dice's similarity coefficients (DSC). Results: The inter-reader correlation is 0.97 for FGT% and 0.95 for |FGT|. When compared to the average of the two readers’ manual segmentation, the proposed FCM-Atlas method achieves a

  6. Approximation of charge-deposition density in thin slabs irradiated by electrons

    CERN Document Server

    Alouani-Bibi, F; Rogov, Y V; Tabata, T

    2000-01-01

    Charge-deposition distributions in thin slabs irradiated by plane-parallel electron beams are studied. The slabs considered are made of elements with atomic numbers ranging from 4 to 79. The slab thicknesses are from 0.5 to 50 mg/cm sup 2 , and the electron beam energies are from 1 to 10 MeV. Using a new Monte Carlo method (called the trajectory translation method), data on the charge-deposition density have been obtained. Theoretical analysis of these data has been performed. Based on this analysis, a semiempirical model that describes charge-deposition distributions in thin slabs has been developed. The results obtained by the semiempirical model have been compared with those obtained by the PENELOPE Monte Carlo code and show moderate agreement.

  7. Density functional theory calculations of charge transport properties of ‘plate-like’ coronene topological structures

    Indian Academy of Sciences (India)

    ZIRAN CHEN; ZHANRONG HE; YOUHUI XU; WENHAO YU

    2017-09-01

    Charge transport rate is one of the key parameters determining the performance of organic electronic devices. In this paper, we used density functional theory (DFT) at the M06-2X/6−31+G(d) level to compute the charge transport rates of nine coronene topological structures. The results show that the energy gap of these nine coronene derivatives is in the range 2.90–3.30 eV, falling into the organic semiconductor category. The size of the conjugate ring has a large influence on the charge transport properties. Incorporation of methyl groupson the rigid core of tetrabenzocoronene and hexabenzocoronene is more conducive to the hole transport of the molecule than incorporating methoxyl groups. The derivatisation of a ‘long plate-like’ coronene with methoxylgroups facilitates both hole and electron transport. This class of molecules can thus be used in the design of ambipolar transport semiconductor materials.

  8. Charge density and particle size effects on oligonucleotide and plasmid DNA binding to nanosized hydrotalcite.

    Science.gov (United States)

    Sanderson, Brian A; Sowersby, Drew S; Crosby, Sergio; Goss, Marcus; Lewis, L Kevin; Beall, Gary W

    2013-12-01

    Hydrotalcite (HT) and other layered double metal hydroxides are of great interest as gene delivery and timed release drug delivery systems and as enteric vehicles for biologically active molecules that are sensitive to gastric fluids. HT is a naturally occurring double metal hydroxide that can be synthesized as a nanomaterial consisting of a brucite structure with isomorphous substitution of aluminum ions. These positively charged nanoparticles exhibit plate-like morphology with very high aspect ratios. Biomolecules such as nucleic acids and proteins form strong associations with HT because they can associate with the positively charged layers. The binding of nucleic acids with HT and other nanomaterials is currently being investigated for potential use in gene therapy; however, the binding of specific nucleic acid forms, such as single- and double-stranded DNA, has been little explored. In addition, the effects of charge density and particle size on DNA adsorption has not been studied. In this paper, the binding of different forms of DNA to a series of HTs prepared at different temperatures and with different anion exchange capacities has been investigated. Experiments demonstrated that HTs synthesized at higher temperatures associate with both single- and double-stranded oligomers and circular plasmid DNA more tightly than HTs synthesized at room temperature, likely due to the hydrothermal conditions promoting larger particle sizes. HT with an anion exchange capacity of 300 meq/100 g demonstrated the highest binding of DNA, likely due to the closer match of charge densities between the HT and DNA. The details of the interaction of various forms of DNA with HT as a function of charge density, particle size, and concentration are discussed.

  9. Local distortion in Co-doped LSMO from entropy-maximized charge density distribution

    Energy Technology Data Exchange (ETDEWEB)

    Syed Ali, K.S. [Department of Physics, The Madura College, Madurai 625011 (India); Saravanan, R., E-mail: saragow@dataone.i [Department of Physics, The Madura College, Madurai 625011 (India); Pashchenko, A.V.; Pashchenko, V.P. [Galkin Donetsk Institute of Physics and Technology, National Academy of Sciences of Ukraine, Donetsk 83114 (Ukraine)

    2010-07-09

    Perovskite structure manganites La{sub 0.67}Sr{sub 0.22}Mn{sub 1.11-x}Co{sub x}O{sub 3} were prepared by the solid state reaction method. An X-ray analysis of the structure was undertaken using the Rietveld technique on the experimental powder X-ray diffraction data and, then, a charge density distribution study was undertaken, using the maximum entropy method (MEM). The charge density in the unit cell was reconstructed and the effect of Co{sup 3+} doping in the Mn-O matrix was studied. Local distortions due to Co doping were analyzed and the results are now discussed.

  10. Bond length and charge density variations within extended arm chair defects in graphene.

    Science.gov (United States)

    Warner, Jamie H; Lee, Gun-Do; He, Kuang; Robertson, Alex W; Yoon, Euijoon; Kirkland, Angus I

    2013-11-26

    Extended linear arm chair defects are intentionally fabricated in suspended monolayer graphene using controlled focused electron beam irradiation. The atomic structure is accurately determined using aberration-corrected transmission electron microscopy with monochromation of the electron source to achieve ∼80 pm spatial resolution at an accelerating voltage of 80 kV. We show that the introduction of atomic vacancies in graphene disrupts the uniformity of C-C bond lengths immediately surrounding linear arm chair defects in graphene. The measured changes in C-C bond lengths are related to density functional theory (DFT) calculations of charge density variation and corresponding DFT calculated structural models. We show good correlation between the DFT predicted localized charge depletion and structural models with HRTEM measured bond elongation within the carbon tetragon structure of graphene. Further evidence of bond elongation within graphene defects is obtained from imaging a pair of 5-8-5 divacancies.

  11. Universal Field-Induced Charge-Density-Wave Phase Diagram: Theory versus Experiment

    Science.gov (United States)

    Lebed, A. G.

    2009-07-01

    We suggest a theory of field-induced charge-density-wave phases, generated by high magnetic fields in quasi-low-dimensional conductors. We demonstrate that, in layered quasi-one-dimensional conductors, the corresponding critical magnetic field ratios are universal and do not depend on any fitting parameter. In particular, we find that H1/H0=0.73, H2/H0=0.59, H3/H0=0.49, and H4/H0=0.42, where Hn is a critical field of a phase transition between the field-induced charge-density-wave phases with numbers n and n+1. The suggested theory is in very good qualitative and quantitative agreement with the existing experimental data in α-(ET)2KHg(SCN)4 material.

  12. Charged Multiplicity Density and Number of Participant Nucleons in Relativistic Nuclear Collisions

    Institute of Scientific and Technical Information of China (English)

    SA Ben-Hao; CAI Xu; ZHOU Dai-Mei

    2003-01-01

    The energy and centrality dependencies of charged particle pseudorapidity density in relativistic nuclearcollisions were studied using a hadron and string cascade model, JPCIAE. Both the relativistic p+p experimental dataand the PHOBOS and PHENIX Au+Au data at RHIC energy could be fairly reproduced within the framework ofJPCIAE model and without retuning the model parameters. The predictions for Pb + Pb collisions at the LHC energywere also given. We computed the participant nucleon distributions using different methods. It was found that thenumber of participant nucleons is not a well defined variable both experimentally and theoretically. Thus it may beinappropriate to use the charged particle pseudorapidity density per participant pair .as a function of the number ofparticipant nucleons for distinguishing various theoretical models.

  13. Generation of localized magnetic moments in the charge-density-wave state

    Science.gov (United States)

    Akzyanov, Ramil S.; Rozhkov, Alexander V.

    2015-08-01

    We propose a mechanism explaining the generation of localized magnetic moments in charge-density-wave compounds. Our model Hamiltonian describes an Anderson impurity placed in a host material exhibiting the charge-density wave. There is a region of the model's parameter space, where even weak Coulomb repulsion on the impurity site is able to localize the magnetic moment on the impurity. The phase diagram of a single impurity at T = 0 is mapped. To establish the connection with experiment, the thermodynamic properties of a random impurity ensemble is studied. Magnetic susceptibility of the ensemble diverges at low temperature; heat capacity as a function of the magnetic field demonstrates pronounced low field peak. Both features are consistent with experiments on orthorhombic TaS3 and blue bronze.

  14. Measurements of Ionospheric Density, Temperature, and Spacecraft Charging in a Space Weather Constellation

    Science.gov (United States)

    Balthazor, R. L.; McHarg, M. G.; Wilson, G.

    2016-12-01

    The Integrated Miniaturized Electrostatic Analyzer (IMESA) is a space weather sensor developed by the United States Air Force Academy and integrated and flown by the DoD's Space Test Program. IMESA records plasma spectrograms from which can be derived plasma density, temperature, and spacecraft frame charging. Results from IMESA currently orbiting on STPSat-3 are presented, showing frame charging effects dependent on a complex function of the number of solar panel cell strings switched in, solar panel current, and plasma density. IMESA will fly on four more satellites launching in the next two calendar years, enabling an undergraduate DoD space weather constellation in Low Earth Orbit that has the ability to significantly improve space weather forecasting capabilities using assimilative forecast models.

  15. Charge density waves in the graphene sheets of the superconductor CaC(6).

    Science.gov (United States)

    Rahnejat, K C; Howard, C A; Shuttleworth, N E; Schofield, S R; Iwaya, K; Hirjibehedin, C F; Renner, Ch; Aeppli, G; Ellerby, M

    2011-11-29

    Graphitic systems have an electronic structure that can be readily manipulated through electrostatic or chemical doping, resulting in a rich variety of electronic ground states. Here we report the first observation and characterization of electronic stripes in the highly electron-doped graphitic superconductor, CaC(6), by scanning tunnelling microscopy and spectroscopy. The stripes correspond to a charge density wave with a period three times that of the Ca superlattice. Although the positions of the Ca intercalants are modulated, no displacements of the carbon lattice are detected, indicating that the graphene sheets host the ideal charge density wave. This provides an exceptionally simple material-graphene-as a starting point for understanding the relation between stripes and superconductivity. Furthermore, our experiments suggest a strategy to search for superconductivity in graphene, namely in the vicinity of striped 'Wigner crystal' phases, where some of the electrons crystallize to form a superlattice.

  16. Semilocal and Hybrid Density Embedding Calculations of Ground-State Charge-Transfer Complexes

    CERN Document Server

    Laricchia, S; Della Sala, F; 10.1063/1.4795825

    2013-01-01

    We apply the frozen density embedding method, using a full relaxation of embedded densities through a freeze-and-thaw procedure, to study the electronic structure of several benchmark ground-state charge-transfer complexes, in order to assess the merits and limitations of the approach for this class of systems. The calculations are performed using both semilocal and hybrid exchange-correlation (XC) functionals. The results show that embedding calculations using semilocal XC functionals yield rather large deviations with respect to the corresponding supermolecular calculations. Due to a large error cancellation effect, however, they can often provide a relatively good description of the electronic structure of charge-transfer complexes, in contrast to supermolecular calculations performed at the same level of theory. On the contrary, when hybrid XC functionals are employed, both embedding and supermolecular calculations agree very well with each other and with the reference benchmark results. In conclusion, fo...

  17. Poly(ethylene glycol)-block-cationic polylactide nanocomplexes of differing charge density for gene delivery.

    Science.gov (United States)

    Chen, Chih-Kuang; Jones, Charles H; Mistriotis, Panagiotis; Yu, Yun; Ma, Xiaoni; Ravikrishnan, Anitha; Jiang, Ming; Andreadis, Stelios T; Pfeifer, Blaine A; Cheng, Chong

    2013-12-01

    Representing a new type of biodegradable cationic block copolymer, well-defined poly(ethylene glycol)-block-cationic polylactides (PEG-b-CPLAs) with tertiary amine-based cationic groups were synthesized by thiol-ene functionalization of an allyl-functionalized diblock precursor. Subsequently the application of PEG-b-CPLAs as biodegradable vectors for the delivery of plasmid DNAs (pDNAs) was investigated. Via the formation of PEG-b-CPLA:pDNA nanocomplexes by spontaneous electrostatic interaction, pDNAs encoding luciferase or enhanced green fluorescent protein were successfully delivered to four physiologically distinct cell lines (including macrophage, fibroblast, epithelial, and stem cell). Formulated nanocomplexes demonstrated high levels of transfection with low levels of cytotoxicity and hemolysis when compared to a positive control. Biophysical characterization of charge densities of nanocomplexes at various polymer:pDNA weight ratios revealed a positive correlation between surface charge and gene delivery. Nanocomplexes with high surface charge densities were utilized in an in vitro serum gene delivery inhibition assay, and effective gene delivery was observed despite high levels of serum. Overall, these results help to elucidate the influence of charge, size, and PEGylation of nanocomplexes upon the delivery of nucleic acids in physiologically relevant conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Exploring effective interactions through transition charge density study of 70,72,74,76Ge nuclei

    Indian Academy of Sciences (India)

    A Shukla; P K Raina; P K Rath

    2005-02-01

    Transition charge densities (TCD) for $0^{+} → 2_{1}^{+}$ excitation have been calculated for 70, 72, 74, 76Ge nuclei within microscopic variational framework employing 23/2, 15/2, 21/2 and 19/2 valence space. The calculated TCDs for different monopole variants of Kuo interaction are compared with available experimental results. Other systematics like reduced transition probabilities (2) and static quadrupole moments (2) are also presented. It is observed that the transition density study acts as a sensitive probe for discriminating the response of different parts of effective interactions.

  19. Extended phonon collapse in the charge-density-wave compound NbSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Frank [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Materials Science Division, Argonne National Laboratory, Argonne, Illinois (United States); Rosenkranz, Stephan; Castellan, John-Paul; Osborn, Raymond [Materials Science Division, Argonne National Laboratory, Argonne, Illinois (United States); Hott, Roland; Heid, Rolf; Bohnen, Klaus-Peter [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Egami, Takeshi [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee (United States); Said, Ayman [Advanced Photon Source, Argonne National Laboratory, Illinois (United States); Reznik, Dmitry [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Department of Physics, University of Colorado at Boulder, Boulder, Colorado (United States)

    2011-07-01

    We investigated the phonon softening in the charge density wave compound NbSe{sub 2} using the high-resolution hard inelastic X-ray scattering beamline 30-ID-C at the Advanced Photon Source, Argonne National Laboratory. The acoustic {sigma}{sub 1} phonon branch was measured from the zone center {gamma} to the M point at temperatures between 250 K and 8 K across the CDW transition at T{sub CDW}=33 K. Density functional theory calculations for the lattice dynamical properties which predict an extended phonon breakdown are used to analyze the detailed nature of the softening phonon branch.

  20. Predicting Chemical Reactivity from the Charge Density through Gradient Bundle Analysis: Moving beyond Fukui Functions.

    Science.gov (United States)

    Morgenstern, Amanda; Wilson, Timothy R; Eberhart, M E

    2017-06-08

    Predicting chemical reactivity is a major goal of chemistry. Toward this end, atom condensed Fukui functions of conceptual density functional theory have been used to predict which atom is most likely to undergo electrophilic or nucleophilic attack, providing regioselectivity information. We show that the most probable regions for electrophilic attack within each atom can be predicted through analysis of gradient bundle volumes, a property that depends only on the charge density of the neutral molecules. We also introduce gradient bundle condensed Fukui functions to compare the stereoselectivity information obtained from gradient bundle volume analysis. We demonstrate this method using the test set of molecular fluorine, oxygen, nitrogen, carbon monoxide, and hydrogen cyanide.

  1. Tuning the charge density wave and superconductivity in CuxTaS2

    NARCIS (Netherlands)

    Wagner, K.E.; Morosan, E.; Hor, Y.S.; Tao, J.; Zhu, Y.; Sanders, T.; McQueen, T.M.; Zandbergen, H.W.; Williams, A.J.; West, D.V.; Cava, R.J.

    2008-01-01

    We report the characterization of layered 2H-type CuxTaS2 for 0≤x≤0.12. The charge density wave (CDW), at 70 K for TaS2, is destabilized with Cu doping. The sub-1 K superconducting transition in undoped 2H-TaS2 jumps quickly to 2.5 K at low x, increases to 4.5 K at the optimal composition Cu0.04TaS2

  2. Field-Induced Dynamic Diamagnetism in a Charge-Density-Wave System

    Science.gov (United States)

    Harrison, N.; Mielke, C. H.; Christianson, A. D.; Brooks, J. S.; Tokumoto, M.

    2001-02-01

    ac susceptibility measurements of the charge-density-wave (CDW) compound α-\\(BEDT-TTF\\)2-KHg\\(SCN\\)4 at magnetic fields, μ0H>23 T, above its Pauli paramagnetic limit, reveal unambiguously that the magnetic hysteresis observed previously within this CDW phase is diamagnetic and can only be explained by induced currents. It is argued that the ensemble of experimental techniques amounts to a strong case for dissipationless conductivity within this phase.

  3. The scaling dimension of low lying Dirac eigenmodes and of the topological charge density

    Energy Technology Data Exchange (ETDEWEB)

    Aubin, C. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Bernard, C. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Gottlieb, Steven [Department of Physics, Indiana Univerity, Bloomington, IN 47405 (United States); Gregory, E.B. [Department of Physics, University of Arizona, Tucson, AZ 85721 (United States); Heller, Urs M. [American Physical Society, One Research Road, Box 9000, Ridge, NY 11961 (United States); Hetrick, J.E. [Physics Department, University of the Pacific, Stockton, CA 95211 (United States); Osborn, J.; Sugar, R. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Forcrand, Ph. de [Institute for Theoretical Physics, ETH Zuerich, CH-8093 Zurich (Switzerland); CERN, Theory Division, CH-1211 Geneva 23 (Switzerland); Jahn, O. [Center for Theoretical Physics, MIT, Cambridge, MA 02139 (United States)

    2005-03-15

    As a quantitative measure of localization, the inverse participation ratio of low lying Dirac eigenmodes and topological charge density is calculated on quenched lattices over a wide range of lattice spacings and volumes. Since different topological objects (instantons, vortices, monopoles, and artifacts) have different co-dimension, scaling analysis provides information on the amount of each present and their correlation with the localization of low lying eigenmodes.

  4. Lateral diffusion of the topological charge density in stochastic optical fields

    CSIR Research Space (South Africa)

    Roux, FS

    2010-01-01

    Full Text Available is described by a diffusion process that has a diffusion parameter which depends on the propagation distance. Keywords: optical vortex, singular optics, stochastic optical field, topological charge density, diffusion equation 1. Introduction The spatial... [1, 2], which measures the continuous phase distortions and then removes them with a continuous deformable mirror. The problem with this approach comes in with strong scintillation, when the phase distortions are severe enough to give rise...

  5. Time-domain pumping a quantum-critical charge density wave ordered material

    Science.gov (United States)

    Matveev, O. P.; Shvaika, A. M.; Devereaux, T. P.; Freericks, J. K.

    2016-09-01

    We determine the exact time-resolved photoemission spectroscopy for a nesting driven charge density wave (described by the spinless Falicov-Kimball model within dynamical mean-field theory). The pump-probe experiment involves two light pulses: the first is an ultrashort intense pump pulse that excites the system into nonequilibrium, and the second is a lower amplitude, higher frequency probe pulse that photoexcites electrons. We examine three different cases: the strongly correlated metal, the quantum-critical charge density wave, and the critical Mott insulator. Our results show that the quantum critical charge density wave has an ultraefficient relaxation channel that allows electrons to be de-excited during the pump pulse, resulting in little net excitation. In contrast, the metal and the Mott insulator show excitations that are closer to what one expects from these systems. In addition, the pump field produces spectral band narrowing, peak sharpening, and a spectral gap reduction, all of which rapidly return to their field free values after the pump is over.

  6. Near Gap Excitation of Collective Modes in a Charge Density Wave

    Science.gov (United States)

    Leuenberger, Dominik; Sobota, Jonathan; Yang, Shuolong; Kemper, Alexander; Giraldo, Paula; Moore, Rob; Fisher, Ian; Kirchmann, Patrick; Devereaux, Thomas; Shen, Zhi-Xun

    2015-03-01

    We present time- and angle-resolved photoemission spectroscopy (trARPES) measurements on the charge density wave system's (CDW) CeTe3. Optical excitation transiently populates the unoccupied band structure and reveals a CDW gap size of 2 Δ = 0 . 59 eV. In addition, the occupied Te- 5 p band dispersion is coherently modified by three collective modes. First, the spatial polarization of the modes is analyzed by fits of a transient model dispersion and DFT frozen phonon calculations. We thereby demonstrate how the rich information from trARPES allows identification of collective modes and their spatial polarization, which explains the mode-dependent coupling to charge order. Second, the exciting photon energy hν was gradually lowered towards 2 Δ , at constant optical excitation density. The coherent response of the amplitude mode deviates from the optical conductivity, which is dominated by direct interband transitions between the lower and upper CDW bands. The measured hν -dependence can be reproduced by a calculated joint density of states for optical transition between bands with different orbital character. This finding suggests, that the coherent response of the CDW amplitude mode is dominated by photo-doping of the charge ordering located in the Te-planes.

  7. Charge-carrier mobilities in disordered semiconducting polymers: effects of carrier density and electric field

    Energy Technology Data Exchange (ETDEWEB)

    Meisel, K.D.; Pasveer, W.F.; Cottaar, J.; Bobbert, P.A.; Michels, M.A.J. [Group Polymer Physics, Eindhoven Polymer Laboratories and Dutch Polymer Institute, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Tanase, C.; Blom, P.W.M. [Materials Science Centre and Dutch Polymer Institute, Nijenborgh 4, 9747 AG Groningen (Netherlands); Coehoorn, R.; Leeuw, D.M. de [Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA Eindhoven (Netherlands)

    2006-02-01

    We model charge transport in disordered semiconducting polymers by hopping of charge carriers on a square lattice of sites with Gaussian on-site energy disorder, using Fermi-Dirac statistics. From numerically exact solutions of the Master equation, we study the dependence of the charge-carrier mobility on temperature, carrier density, and electric field. Our results are used in calculating current-voltage characteristics of hole-only polymer diodes. It is found that very good fits to experimental current-voltage characteristics can be obtained at different temperatures, with reasonable fitting parameters for the width of the Gaussian density of states and the lattice constant. In agreement with the experiments we find that the density dependence is dominant over the field dependence. Only at high fields and low temperatures the field dependence becomes noticeable. The potential and current distribution show strong inhomogeneities, which may have important consequences for the operation of polymer opto-electronic devices. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. New Density Estimation Methods for Charged Particle Beams With Applications to Microbunching Instability

    Energy Technology Data Exchange (ETDEWEB)

    Balsa Terzic, Gabriele Bassi

    2011-07-01

    In this paper we discuss representations of charge particle densities in particle-in-cell (PIC) simulations, analyze the sources and profiles of the intrinsic numerical noise, and present efficient methods for their removal. We devise two alternative estimation methods for charged particle distribution which represent significant improvement over the Monte Carlo cosine expansion used in the 2d code of Bassi, designed to simulate coherent synchrotron radiation (CSR) in charged particle beams. The improvement is achieved by employing an alternative beam density estimation to the Monte Carlo cosine expansion. The representation is first binned onto a finite grid, after which two grid-based methods are employed to approximate particle distributions: (i) truncated fast cosine transform (TFCT); and (ii) thresholded wavelet transform (TWT). We demonstrate that these alternative methods represent a staggering upgrade over the original Monte Carlo cosine expansion in terms of efficiency, while the TWT approximation also provides an appreciable improvement in accuracy. The improvement in accuracy comes from a judicious removal of the numerical noise enabled by the wavelet formulation. The TWT method is then integrated into Bassi's CSR code, and benchmarked against the original version. We show that the new density estimation method provides a superior performance in terms of efficiency and spatial resolution, thus enabling high-fidelity simulations of CSR effects, including microbunching instability.

  9. Intermolecular interactions, charge-density distribution and the electrostatic properties of pyrazinamide anti-TB drug molecule: an experimental and theoretical charge-density study.

    Science.gov (United States)

    Rajalakshmi, Gnanasekaran; Hathwar, Venkatesha R; Kumaradhas, Poomani

    2014-06-01

    An experimental charge-density analysis of pyrazinamide (a first line antitubercular drug) was performed using high-resolution X-ray diffraction data [(sin θ/λ)max = 1.1 Å(-1)] measured at 100 (2) K. The structure was solved by direct methods using SHELXS97 and refined by SHELXL97. The total electron density of the pyrazinamide molecule was modeled using the Hansen-Coppens multipole formalism implemented in the XD software. The topological properties of electron density determined from the experiment were compared with the theoretical results obtained from CRYSTAL09 at the B3LYP/6-31G** level of theory. The crystal structure was stabilized by N-H...N and N-H...O hydrogen bonds, in which the N3-H3B...N1 and N3-H3A...O1 interactions form two types of dimers in the crystal. Hirshfeld surface analysis was carried out to analyze the intermolecular interactions. The fingerprint plot reveals that the N...H and O...H hydrogen-bonding interactions contribute 26.1 and 18.4%, respectively, of the total Hirshfeld surface. The lattice energy of the molecule was calculated using density functional theory (B3LYP) methods with the 6-31G** basis set. The molecular electrostatic potential of the pyrazinamide molecule exhibits extended electronegative regions around O1, N1 and N2. The existence of a negative electrostatic potential (ESP) region just above the upper and lower surfaces of the pyrazine ring confirm the π-electron cloud.

  10. Sequential tentacle grafting and charge modification for enhancing charge density of mono-sized beads for facilitated protein refolding and purification from inclusion bodies.

    Science.gov (United States)

    Dong, Xiao-Yan; Chen, Ran; Yang, Chun-Yan; Sun, Yan

    2014-06-20

    We have previously found that addition of like-charged media in a refolding solution can greatly enhance the refolding of pure proteins by suppressing protein aggregation. Herein, negatively charged mono-sized microspheres with sulfonic groups were fabricated to explore the facilitating effect of like-charged media on the refolding of enhanced green fluorescent protein (EGFP) expressed as inclusion bodies (IBs). A sequential polymer-tentacle grafting and sulfonate modification strategy was developed to increase the charge density of mono-sized poly(glycidyl methacrylate) (pGMA) beads (2.4μm). Namely, GMA was first grafted onto the beads by grafting polymerization to form poly(GMA) tentacles on the pGMA beads, and then the epoxy groups on the tentacles were converted into sulfonic groups by modification with sodium sulfite. By this fabrication strategy, the charge density of the beads reached 793μmol/g, about 2.8 times higher than that modified without prior grafting of the pGMA beads (285μmol/g). The negatively charged beads of different charge densities were used for facilitating the refolding of like-charged EGFP from IBs. The refolding yield as well as refolding rate increased with increasing charge density. The anti-aggregation effects of urea and like-charged microspheres were synergetic. In addition, partial purification of EGFP was achieved because the ion-exchange adsorption led to 52% removal of positively charged contaminant proteins in the refolded solution. Finally, reusability of the tentacle beads was demonstrated by repetitive EGFP refolding and recovery cycles. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The ESR1 (6q25 locus is associated with calcaneal ultrasound parameters and radial volumetric bone mineral density in European men.

    Directory of Open Access Journals (Sweden)

    Kate L Holliday

    Full Text Available PURPOSE: Genome-wide association studies (GWAS have identified 6q25, which incorporates the oestrogen receptor α gene (ESR1, as a quantitative trait locus for areal bone mineral density (BMD(a of the hip and lumbar spine. The aim of this study was to determine the influence of this locus on other bone health outcomes; calcaneal ultrasound (QUS parameters, radial peripheral quantitative computed tomography (pQCT parameters and markers of bone turnover in a population sample of European men. METHODS: Eight single nucleotide polymorphisms (SNP in the 6q25 locus were genotyped in men aged 40-79 years from 7 European countries, participating in the European Male Ageing Study (EMAS. The associations between SNPs and measured bone parameters were tested under an additive genetic model adjusting for centre using linear regression. RESULTS: 2468 men, mean (SD aged 59.9 (11.1 years had QUS measurements performed and bone turnover marker levels measured. A subset of 628 men had DXA and pQCT measurements. Multiple independent SNPs showed significant associations with BMD using all three measurement techniques. Most notably, rs1999805 was associated with a 0.10 SD (95%CI 0.05, 0.16; p = 0.0001 lower estimated BMD at the calcaneus, a 0.14 SD (95%CI 0.05, 0.24; p = 0.004 lower total hip BMD(a, a 0.12 SD (95%CI 0.02, 0.23; p = 0.026 lower lumbar spine BMD(a and a 0.18 SD (95%CI 0.06, 0.29; p = 0.003 lower trabecular BMD at the distal radius for each copy of the minor allele. There was no association with serum levels of bone turnover markers and a single SNP which was associated with cortical density was also associated with cortical BMC and thickness. CONCLUSIONS: Our data replicate previous associations found between SNPs in the 6q25 locus and BMD(a at the hip and extend these data to include associations with calcaneal ultrasound parameters and radial volumetric BMD.

  12. Symmetry breaking induced by charge density and the entropy of interacting fields

    Science.gov (United States)

    Bekenstein, Jacob D.; Guendelman, E. I.

    1987-01-01

    We study interacting complex scalar field theories with global U(1) symmetry and concave potentials. It is usually assumed that spontaneous symmetry breaking is excluded for such interaction. However, we show that degenerate ground states appear when the system is considered as a charged medium, which we take to be so large that it makes sense to speak of a uniform, finite, charge density. This of course implies that we are considering as ground states solutions that select a particular Lorentz frame. The consequent symmetry breaking is accompanied by the usual Goldstone modes. It makes topological solitons possible in 1+1 dimensions. Further, a new kind of nontopological solitons appears, again in 1+1 dimensions. These are embedded in a uniformly charged background. Unlike the Friedberg-Lee-Sirlin solitons, those studied here do not require a complicatedly shaped potential to exist. Although Derrick's theorem, which forbids higher-dimensional solitons, cannot be proved in the present context, it appears that such solitons are still forbidden in the presence of finite charge density. When the field is confined to a box, the frequency spectrum is, classically, a continuum. This is in sharp contrast to the situation for linear fields. However, semiclassical quantization, or the requirement that charge be quantized, both make the spectrum discrete. We show by general arguments that the energy spectrum (distinct from the frequency spectrum for nonlinear fields) for the interacting field in a box must have widely spaced levels. For the case of a quartic potential we compute the energy levels exactly in 1+1 dimensions, and verify this conclusion directly. The interacting scalar field thus complies in detail with the bound on specific entropy proposed by one of us earlier as applicable to all finite physical systems.

  13. Expanding the Scope of Density Derived Electrostatic and Chemical Charge Partitioning to Thousands of Atoms.

    Science.gov (United States)

    Lee, Louis P; Limas, Nidia Gabaldon; Cole, Daniel J; Payne, Mike C; Skylaris, Chris-Kriton; Manz, Thomas A

    2014-12-01

    The density derived electrostatic and chemical (DDEC/c3) method is implemented into the onetep program to compute net atomic charges (NACs), as well as higher-order atomic multipole moments, of molecules, dense solids, nanoclusters, liquids, and biomolecules using linear-scaling density functional theory (DFT) in a distributed memory parallel computing environment. For a >1000 atom model of the oxygenated myoglobin protein, the DDEC/c3 net charge of the adsorbed oxygen molecule is approximately -1e (in agreement with the Weiss model) using a dynamical mean field theory treatment of the iron atom, but much smaller in magnitude when using the generalized gradient approximation. For GaAs semiconducting nanorods, the system dipole moment using the DDEC/c3 NACs is about 5% higher in magnitude than the dipole computed directly from the quantum mechanical electron density distribution, and the DDEC/c3 NACs reproduce the electrostatic potential to within approximately 0.1 V on the nanorod's solvent-accessible surface. As examples of conducting materials, we study (i) a 55-atom Pt cluster with an adsorbed CO molecule and (ii) the dense solids Mo2C and Pd3V. Our results for solid Mo2C and Pd3V confirm the necessity of a constraint enforcing exponentially decaying electron density in the tails of buried atoms.

  14. Testing the concept of hypervalency: charge density analysis of K2SO4.

    Science.gov (United States)

    Schmøkel, Mette S; Cenedese, Simone; Overgaard, Jacob; Jørgensen, Mads R V; Chen, Yu-Sheng; Gatti, Carlo; Stalke, Dietmar; Iversen, Bo B

    2012-08-06

    One of the most basic concepts in chemical bonding theory is the octet rule, which was introduced by Lewis in 1916, but later challenged by Pauling to explain the bonding of third-row elements. In the third row, the central atom was assumed to exceed the octet by employing d orbitals in double bonding leading to hypervalency. Ever since, polyoxoanions such as SO(4)(2-), PO(4)(3-), and ClO(4)(-) have been paradigmatic examples for the concept of hypervalency in which the double bonds resonate among the oxygen atoms. Here, we examine S-O bonding by investigating the charge density of the sulfate group, SO(4)(2-), within a crystalline environment based both on experimental and theoretical methods. K(2)SO(4) is a high symmetry inorganic solid, where the crystals are strongly affected by extinction effects. Therefore, high quality, very low temperature single crystal X-ray diffraction data were collected using a small crystal (∼30 μm) and a high-energy (30 keV) synchrotron beam. The experimental charge density was determined by multipole modeling, whereas a theoretical density was obtained from periodic ab initio DFT calculations. The chemical bonding was jointly analyzed within the framework of the Quantum Theory of Atoms In Molecules only using quantities derived from an experimental observable (the charge density). The combined evidence suggests a bonding situation where the S-O interactions can be characterized as highly polarized, covalent bonds, with the "single bond" description significantly prevailing over the "double bond" picture. Thus, the study rules out the hypervalent description of the sulfur atom in the sulfate group.

  15. Long-range charge-density-wave proximity effect at cuprate/manganate interfaces

    Science.gov (United States)

    Frano, A.; Blanco-Canosa, S.; Schierle, E.; Lu, Y.; Wu, M.; Bluschke, M.; Minola, M.; Christiani, G.; Habermeier, H. U.; Logvenov, G.; Wang, Y.; van Aken, P. A.; Benckiser, E.; Weschke, E.; Le Tacon, M.; Keimer, B.

    2016-08-01

    The interplay between charge density waves (CDWs) and high-temperature superconductivity is currently under intense investigation. Experimental research on this issue is difficult because CDW formation in bulk copper oxides is strongly influenced by random disorder, and a long-range-ordered CDW state in high magnetic fields is difficult to access with spectroscopic and diffraction probes. Here we use resonant X-ray scattering in zero magnetic field to show that interfaces with the metallic ferromagnet La2/3Ca1/3MnO3 greatly enhance CDW formation in the optimally doped high-temperature superconductor YBa2Cu3O6+δ (δ ~ 1), and that this effect persists over several tens of nanometres. The wavevector of the incommensurate CDW serves as an internal calibration standard of the charge carrier concentration, which allows us to rule out any significant influence of oxygen non-stoichiometry, and to attribute the observed phenomenon to a genuine electronic proximity effect. Long-range proximity effects induced by heterointerfaces thus offer a powerful method to stabilize the charge-density-wave state in the cuprates and, more generally, to manipulate the interplay between different collective phenomena in metal oxides.

  16. Tailoring Membrane Nanostructure and Charge Density for High Electrokinetic Energy Conversion Efficiency.

    Science.gov (United States)

    Haldrup, Sofie; Catalano, Jacopo; Hinge, Mogens; Jensen, Grethe V; Pedersen, Jan S; Bentien, Anders

    2016-02-23

    The electrokinetic energy conversion (EKEC) of hydraulic work directly into electrical energy has been investigated in charged polymeric membranes with different pore charge densities and characteristic diameters of the nanoporous network. The membranes were synthesized from blends of nitrocellulose and sulfonated polystyrene (SPS) and were comprehensively characterized with respect to structure, composition, and transport properties. It is shown that the SPS can be used as a sacrificial pore generation medium to tune the pore size and membrane porosity, which in turn highly affects the transport properties of the membranes. Furthermore, it is shown that very high EKEC efficiencies (>35%) are encountered in a rather narrow window of the properties of the nanoporous membrane network, that is, with pore diameters of ca. 10 nm and pore charge densities of 4.6 × 10(2) to 1.5 × 10(3) mol SO3(-) m(-3) for dilute solutions (0.03 M LiCl). The high absolute value of the efficiency combined with the determination of the optimal membrane morphology makes membrane-based EKEC devices a step closer to practical applications and high-performance membrane design less empirical.

  17. Long-range charge-density-wave proximity effect at cuprate/manganate interfaces.

    Science.gov (United States)

    Frano, A; Blanco-Canosa, S; Schierle, E; Lu, Y; Wu, M; Bluschke, M; Minola, M; Christiani, G; Habermeier, H U; Logvenov, G; Wang, Y; van Aken, P A; Benckiser, E; Weschke, E; Le Tacon, M; Keimer, B

    2016-08-01

    The interplay between charge density waves (CDWs) and high-temperature superconductivity is currently under intense investigation. Experimental research on this issue is difficult because CDW formation in bulk copper oxides is strongly influenced by random disorder, and a long-range-ordered CDW state in high magnetic fields is difficult to access with spectroscopic and diffraction probes. Here we use resonant X-ray scattering in zero magnetic field to show that interfaces with the metallic ferromagnet La2/3Ca1/3MnO3 greatly enhance CDW formation in the optimally doped high-temperature superconductor YBa2Cu3O6+δ (δ ∼ 1), and that this effect persists over several tens of nanometres. The wavevector of the incommensurate CDW serves as an internal calibration standard of the charge carrier concentration, which allows us to rule out any significant influence of oxygen non-stoichiometry, and to attribute the observed phenomenon to a genuine electronic proximity effect. Long-range proximity effects induced by heterointerfaces thus offer a powerful method to stabilize the charge-density-wave state in the cuprates and, more generally, to manipulate the interplay between different collective phenomena in metal oxides.

  18. Association of 25-hydroxyvitamin D with areal and volumetric measures of bone mineral density and parathyroid hormone: impact of vitamin D-binding protein and its assays

    Science.gov (United States)

    Jemielita, T. O.; Leonard, M. B.; Baker, J.; Sayed, S.; Zemel, B. S.; Shults, J.; Herskovitz, R.

    2016-01-01

    Summary A comparison of the association of different forms of 25-hydroxyvitamin D [25(OH)D] with parathyroid hormone (PTH) and with areal and volumetric bone mineral density (BMD) demonstrated that bioavailable and free 25(OH)D do not provide a better index of vitamin D status in terms of bone health compared to total 25(OH)D. Introduction This study aims to compare measures of vitamin D-binding protein (DBP) using a monoclonal versus polyclonal ELISA and assess correlations of total versus estimated free and bioavailable 25(OH)D with BMD and PTH concentrations. Methods DXA and peripheral quantitative CT (pQCT) scans were obtained in 304 adults (158 black, 146 white), ages 21–80 years. Free and bioavailable 25(OH)D were calculated from total 25(OH)D, DBP, and albumin concentrations. Multivariable linear regression with standardized beta coefficients was used to evaluate associations of bone measures and PTH with total, free, and bioavailable 25(OH)D. Results Measures of DBP obtained using a monoclonal versus polyclonal ELISA were not correlated (rs=0.02, p=0.76). Free and bioavailable 25(OH)D based on the polyclonal assay were lower in black versus white participants (p<0.0001); this race difference was not evident using the monoclonal assay. Adjusted for age, sex, calcium intake, and race, all forms of 25(OH)D were negatively associated with PTH, but the absolute coefficient was greatest for total 25(OH)D (−0.34, p<0.001) versus free/bioavailable 25(OH)D (−0.18/−0.24 depending on DBP assay, p≤0.003). In analyses stratified on race, none of the measures of 25(OH)D were associated with BMD across DXA and pQCT sites. Conclusions The monoclonal versus polyclonal ELISA yielded highly discrepant measures of DBP, particularly among black individuals, likely related to established race differences in DBP polymorphisms. Contrary to prior studies, our findings indicate that using DBP to estimate bioavailable and free 25(OH)D does not provide a better index of

  19. Orchidectomy-induced alterations in volumetric bone density, cortical porosity and strength of femur are attenuated by dietary conjugated linoleic acid in aged guinea pigs.

    Science.gov (United States)

    DeGuire, Jason R; Mak, Ivy L; Lavery, Paula; Agellon, Sherry; Wykes, Linda J; Weiler, Hope A

    2015-04-01

    Age-related osteoporosis and sarcopenia are ascribed in part to reductions in anabolic hormones. Dietary conjugated linoleic acid (CLA) improves lean and bone mass, but its impact during androgen deficiency is not known. This study tested if CLA would attenuate the effects of orchidectomy (ORX)-induced losses of bone and lean tissue. Male guinea pigs (n=40; 70-72 weeks), were randomized into four groups: (1) SHAM+Control diet, (2) SHAM+CLA diet, (3) ORX+Control diet, (4) ORX+CLA diet. Baseline blood sampling and dual-energy X-ray absorptiometry (DXA) scans were conducted, followed by surgery 4 days later with the test diets started 7 days after baseline sampling. Serial blood sampling and DXA scans were repeated 2, 4, 8 and 16 weeks on the test diets. Body composition and areal BMD (aBMD) of whole body, lumbar spine, femur and tibia were measured using DXA. At week 16, muscle protein fractional synthesis rate (FSR), volumetric BMD (vBMD), microarchitecture and bone strength were assessed. Body weight declined after SHAM and ORX surgery, with slower recovery in the ORX group. Dietary CLA did not affect weight or lean mass, but attenuated gains in fat mass. Lean mass was stable in SHAM and reduced in ORX by 2 weeks with whole body and femur bone mineral content (BMC) reduced by 4 weeks; CLA did not alter BMC. By week 16 ORX groups had lower free testosterone and myofibrillar FSR, yet higher cortisol, osteocalcin and ionized calcium with no alterations due to CLA. ORX+Control had higher prostaglandin E2 (PGE2) and total alkaline phosphatase compared to SHAM+Control whereas ORX+CLA were not different from SHAM groups. Femur metaphyseal vBMD was reduced in ORX+CTRL with the reduction attenuated by CLA. Femur cortical thickness (Ct.Th.) and biomechanical strength were reduced and cortical porosity (Ct.Po.) elevated by ORX and attenuated by CLA. This androgen deficient model with a sarcopenic-osteoporotic phenotype similar to aging men responded to dietary CLA with

  20. Investigation of asymmetric alcohol dehydrogenase (ADH) reduction of acetophenone derivatives: effect of charge density.

    Science.gov (United States)

    Naik, Hemantkumar G; Yeniad, Bahar; Koning, Cor E; Heise, Andreas

    2012-07-01

    In an effort to study the effect of substituent groups of the substrate on the alcohol dehydrogenase (ADH) reductions of aryl-alkyl ketones, several derivatives of acetophenone have been evaluated against ADHs from Lactobacillus brevis (LB) and Thermoanaerobacter sp. (T). Interestingly, ketones with non-demanding (neutral) para-substituents were reduced to secondary alcohols by these enzymes in enantiomerically pure form whereas those with demanding (ionizable) substituents could not be reduced. The effect of substrate size, their solubility in the reaction medium, electron donating and withdrawing properties of the ligand and also the electronic charge density distribution on the substrate molecules have been studied and discussed in detail. From the results, it is observed that the electronic charge distribution in the substrate molecules is influencing the orientation of the substrate in the active site of the enzyme and hence the ability to reduce the substrate.

  1. Multiconfiguration Pair-Density Functional Theory Outperforms Kohn-Sham Density Functional Theory and Multireference Perturbation Theory for Ground-State and Excited-State Charge Transfer.

    Science.gov (United States)

    Ghosh, Soumen; Sonnenberger, Andrew L; Hoyer, Chad E; Truhlar, Donald G; Gagliardi, Laura

    2015-08-11

    The correct description of charge transfer in ground and excited states is very important for molecular interactions, photochemistry, electrochemistry, and charge transport, but it is very challenging for Kohn-Sham (KS) density functional theory (DFT). KS-DFT exchange-correlation functionals without nonlocal exchange fail to describe both ground- and excited-state charge transfer properly. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory with a new type of density functional called an on-top density functional. Here we have used MC-PDFT to study challenging ground- and excited-state charge-transfer processes by using on-top density functionals obtained by translating KS exchange-correlation functionals. For ground-state charge transfer, MC-PDFT performs better than either the PBE exchange-correlation functional or CASPT2 wave function theory. For excited-state charge transfer, MC-PDFT (unlike KS-DFT) shows qualitatively correct behavior at long-range with great improvement in predicted excitation energies.

  2. Frequency-dependent response of a pinned charge-density wave

    Science.gov (United States)

    Vinokur, Valerii; Fogler, Michael

    2003-03-01

    Recent theoretical advances in the theory of collective pinning [M. M. Fogler, Phys. Rev. Lett. 88, 186402 (2002)] enable us to go beyond the usual phenomenology in the theory of a finite-frequency response of a pinned charge-density wave (CDW) and to calculate ω and T dependences of the complex dielectric function without additional assumptions. According to our estimates, in typical electrical experiments on CDW, the dominant process is a thermal activation over atypically shallow barriers. It gives rise to a novel T^3/4-dependence of the linear response, in agreement with the experiment. A close analogy with acoustic attenuation in glassy dielectrics is noted.

  3. Metal-charge density wave coexistence in TTF[Ni(dmit){sub 2}]{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kaddour, W. [Laboratoire de Physique des Solides, UMR 8502-CNRS, Univ. Paris-Sud, Orsay F-91405 (France); Laboratoire de Physique de la Matière Condensée, Campus Universitaire, Université de Tunis El-Manar, Tunis 2092 (Tunisia); Auban-Senzier, P.; Raffy, H.; Monteverde, M.; Pouget, J.-P. [Laboratoire de Physique des Solides, UMR 8502-CNRS, Univ. Paris-Sud, Orsay F-91405 (France); Pasquier, C.R., E-mail: pasquier@lps.u-psud.fr [Laboratoire de Physique des Solides, UMR 8502-CNRS, Univ. Paris-Sud, Orsay F-91405 (France); Alemany, P. [Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Canadell, E. [Institut de Ciència de Materials de Barcelona (CSIC), Campus UAB, 08193 Bellaterra (Spain); Valade, L. [Laboratoire de Chimie de Coordination, Route de Narbonne F-31077 Toulouse (France)

    2015-03-01

    We have established a new pressure–temperature phase diagram of TTF[Ni(dmit){sub 2}]{sub 2} based on longitudinal and transverse resistivity measurements under pressure up to 30 kbar. We were able to identify three different charge density wave (CDW) states which all coexist with a metallic state in a wide temperature range and superconductivity at the lowest temperatures. At low pressure, two successive CDW transitions have been clearly identified. These two transitions merge into a single one at 12 kbar. A maximum of this unique CDW transition temperature is observed at 19 kbar.

  4. Orbital localization, charge transfer, and band gaps in semilocal density-functional theory.

    Science.gov (United States)

    Armiento, R; Kümmel, S

    2013-07-19

    We derive an exchange energy functional of generalized gradient form with a corresponding potential that changes discontinuously at integer particle numbers. The functional is semilocal, yet incorporates key features that are connected to the derivative discontinuity of Kohn-Sham density-functional theory. We validate our construction for several paradigm systems and explain how it addresses central well-known deficiencies of antecedent semilocal methods, i.e., the description of charge transfer, properly localized orbitals, and band gaps. We find, e.g., an improved shell structure for atoms, eigenvalues that more closely correspond to ionization energies, and an improved description of band structure where localized states are lowered in energy.

  5. Pressure Dependence of the Charge-Density-Wave Gap in Rare-Earth Tri-Tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Sacchetti, A.; /Zurich, ETH; Arcangeletti, E.; Perucchi, A.; Baldassarre, L.; Postorino, P.; Lupi, S.; /Rome U.; Ru, N.; Fisher, I.R.; /Stanford U., Geballe Lab.; Degiorgi, L.; /Zurich, ETH

    2009-12-14

    We investigate the pressure dependence of the optical properties of CeTe{sub 3}, which exhibits an incommensurate charge-density-wave (CDW) state already at 300 K. Our data are collected in the mid-infrared spectral range at room temperature and at pressures between 0 and 9 GPa. The energy for the single particle excitation across the CDW gap decreases upon increasing the applied pressure, similarly to the chemical pressure by rare-earth substitution. The broadening of the bands upon lattice compression removes the perfect nesting condition of the Fermi surface and therefore diminishes the impact of the CDW transition on the electronic properties of RTe{sub 3}.

  6. A study of transverse charge density of pions in relativistic quantum mechanics

    Institute of Scientific and Technical Information of China (English)

    DONG Yu-Bing; WANG Yi-Zhan

    2011-01-01

    The transverse charge density of pions is calculated based on relativistic quantum mechanics,where the pion is regarded as a quark-antiquark bound state. Corrections from the two spin-1/2 constituents and from the wave function of a quark and antiquark inside the bound system are discussed. The calculated results are compared to the results with a realistic effective Lagrangian approach as well as to that with a simple covariant model where the pion is regarded as a composite system with two scalar particles.

  7. Calculation of the Nuclear Transition Charge Density in a Microscopic sdgIBM-1

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhan-Jun; SANG Jian-ping; LIU Yong

    2000-01-01

    Formulae of proton and neutron boson structure functions (BSF's) are deduced in terms of a microscopic approach of sdgIBM (namely, microscopic sdgIBM). For the nucleus 190Os, the value of BSF's is worked out. Due to the high similarity, the maximum F-spin truncation is made under the full-symmetry approximation. Thereafter, calculations of E2 and E4 transition charge densities (TCD's) are performed in the sdgIBM-1. It is found that the E2 and E4 TCD's can be reproduced quite satisfactorily in the uniform frame of microscopic sdgIBM-1.

  8. Magnetic field dependence of the threshold electric field in unconventional charge density waves

    Science.gov (United States)

    Dóra, Balázs; Virosztek, Attila; Maki, Kazumi

    2002-04-01

    Many experiments suggest that the unidentified low-temperature phase of α-(BEDT-TTF)2KHg(SCN)4 is most likely unconventional charge density wave (UCDW). To further extend this identification we present our theoretical study of the threshold electric field of UCDW in a magnetic field. The magnetic field-temperature phase diagram is very similar to those in a d-wave superconductor. The optical conductivity shows clear features characteristic to both UDW and magnetic field. We find a rather strong field dependence of the threshold electric field, which shows qualitatively good agreement with the experimental data.

  9. Effect of the surface charge density on the creep of copper

    Science.gov (United States)

    Zhmakin, Yu. D.; Rybyanets, V. A.; Nevskii, S. A.; Gromov, V. E.

    2015-01-01

    The creep of polycrystalline copper under the action of high and low electric potentials is studied. At potentials of ±4 kV and ±5 V, the steady-state creep rate decreases, and the effect in the former case is weaker than in the latter by a factor of 2.5. This difference is caused by the fact that the charge density in the sample-capacitor bank system at the high electric potentials is lower than at the low potentials.

  10. Optical properties of the Ce and La ditelluride charge density wave compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lavagnini, M.; Sacchetti, A.; Degiorgi, L.; /Zurich, ETH; Shin, K.Y.; Fisher, I.R.; /Stanford U., Geballe Lab. /Stanford U., Appl. Phys. Dept.

    2010-02-15

    The La and Ce di-tellurides LaTe{sub 2} and CeTe{sub 2} are deep in the charge-density-wave (CDW) ground state even at 300 K. We have collected their electrodynamic response over a broad spectral range from the far infrared up to the ultraviolet. We establish the energy scale of the single particle excitation across the CDW gap. Moreover, we find that the CDW collective state gaps a very large portion of the Fermi surface. Similarly to the related rare earth tri-tellurides, we envisage that interactions and Umklapp processes play a role in the onset of the CDW broken symmetry ground state.

  11. Pushing X-ray charge densities to the limit: Comparative study of CoSb3

    DEFF Research Database (Denmark)

    Schmøkel, Mette Stokkebro; Larsen, Finn Krebs; Overgaard, Jacob

    CoSb3 is a highly important host-guest material for the engineering of high-performance thermoelectric materials.[1] Its crystal structure has empty cavities and when guest atoms are added to CoSb3, its thermoelectric properties are greatly enhanced due to decreased thermal conductivity.[2......] In order to understand the origin of the thermoelectric properties of this family of materials, it is important to understand the crystal structure and chemical bonding of the un-doped host material.[3] This can be achieved through analysis of the charge density, which in principle can be obtained from...

  12. Origin of the charge density wave in 1T-TiSe2

    KAUST Repository

    Zhu, Zhiyong

    2012-06-27

    All-electron ab initio calculations are used to study the microscopic origin of the charge density wave (CDW) in 1T-TiSe2. A purely electronic picture is ruled out as a possible scenario, indicating that the CDW transition in the present system is merely a structural phase transition. The CDW instability is the result of a symmetry lowering by electron correlations occurring with electron localization. Suppression of the CDW in pressurized and in Cu-intercalated 1T-TiSe2 is explained by a delocalization of the electrons, which weakens the correlations and counteracts the symmetry lowering.

  13. Observation of a Charge Density Wave Incommensuration Near the Superconducting Dome in Cux TiSe2

    Science.gov (United States)

    Kogar, A.; de la Pena, G. A.; Lee, Sangjun; Fang, Y.; Sun, S. X.-L.; Lioi, D. B.; Karapetrov, G.; Finkelstein, K. D.; Ruff, J. P. C.; Abbamonte, P.; Rosenkranz, S.

    2017-01-01

    X-ray diffraction was employed to study the evolution of the charge density wave (CDW) in Cux TiSe2 as a function of copper intercalation in order to clarify the relationship between the CDW and superconductivity. The results show a CDW incommensuration arising at an intercalation value coincident with the onset of superconductivity at around x =0.055 (5 ) . Additionally, it was found that the charge density wave persists to higher intercalant concentrations than previously assumed, demonstrating that the CDW does not terminate inside the superconducting dome. A charge density wave peak was observed in samples up to x =0.091 (6 ), the highest copper concentration examined in this study. The phase diagram established in this work suggests that charge density wave incommensuration may play a role in the formation of the superconducting state.

  14. Polysaccharide charge density regulating protein adsorption to air/water interfaces by protein/polysaccharide complex formation

    NARCIS (Netherlands)

    Ganzevles, R.A.; Kosters, H.; Vliet, T. van; Stuart, M.A.C.; Jongh, H.H.J. de

    2007-01-01

    Because the formation of protein/polysaccharide complexes is dominated by electrostatic interaction, polysaccharide charge density is expected to play a major role in the adsorption behavior of the complexes. In this study, pullulan (a non-charged polysaccharide) carboxylated to four different

  15. Volumetric Virtual Environments

    Institute of Scientific and Technical Information of China (English)

    HE Taosong

    2000-01-01

    Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VR system, specifically the modeling, rendering, and manipulations of a volumetric scene.Techniques such as voxel-based object simplification, accelerated volume rendering,fast stereo volume rendering, and volumetric "collision detection" are introduced and improved, with the idea of demonstrating the possibilities and potential benefits of incorporating volumetric models into VR systems.

  16. Electronic properties and charge density of BeZn1−Te alloys

    Indian Academy of Sciences (India)

    C B Swarnkar; U Paliwal; N N Patel; K B Joshi

    2011-06-01

    Electronic band structure calculations are performed for the BeZn1−Te (0 ≤ ≤ 1 in steps of 0.2) alloys following the empirical pseudopotential method. The alloying effects are modelled through the modified virtual crystal approximation. Throughout the composition, valence band maximum resides at the point. The conduction band minimum, however, shifts from to point of symmetry when = 0.27. The observed crossover from direct to indirect bandgap is well in accordance with the experimental observations. Effect of alloying on the density of states is also discussed. The charge density distribution along a few major planes is computed and discussed. The electronic band structure related parameters like bandwidths, bandgaps and ionicity are reported and compared with experimental data wherever available. We also give estimates of cohesive energy and bulk modulus for the alloys.

  17. Charged-particle rapidity density in Au+Au collisions in a quark combination model

    Science.gov (United States)

    Shao, Feng-Lan; Yao, Tao; Xie, Qu-Bing

    2007-03-01

    Rapidity/pseudorapidity densities for charged particles and their centrality, rapidity, and energy dependence in Au+Au collisions at the Relativistic Heavy Ion Collider are studied in a quark combination model. Using a Gaussian-type rapidity distribution for constituent quarks as a result of Landau hydrodynamic evolution, the data at sNN=130,200 GeV at various centralities in full pseudorapidity range are well described, and the charged-particle multiplicities are reproduced as functions of the number of participants. The energy dependence of the shape of the dNch/dη distribution is also described at various collision energies sNN=200,130,62.4 GeV in central collisions with same value of parameters except 19.6 GeV. The calculated rapidity distributions and yields for the charged pions and kaons in central Au+Au collisions at sNN=200 GeV are compared with experimental data of the BRAHMS Collaboration.

  18. Dissipative particle dynamics for systems with high density of charges: Implementation of electrostatic interactions

    Science.gov (United States)

    Gavrilov, A. A.; Chertovich, A. V.; Kramarenko, E. Yu.

    2016-11-01

    In this work, we study the question of how to introduce electrostatic interactions in dissipative particle dynamics (DPD) method in order to correctly reproduce the properties of systems with high density of charges, including those with inhomogeneous charge distribution. To this end, we formulate general requirements for the electrostatic force in DPD and propose a new functional form of the force which suits better for satisfying these requirements than the previously used ones. In order to verify the proposed model, we study the problem of a single polyelectrolyte chain collapse and compare the results with molecular dynamics (MD) simulations in which the exact Coulomb force is used. We show that an excellent quantitative agreement between MD and DPD models is observed if the length parameter D of the proposed electrostatic force is chosen properly; the recommendations concerning the choice of this parameter value are given based on the analysis of a polyelectrolyte chain collapse behavior. Finally, we demonstrate the applicability of DPD with the proposed electrostatic force to studying microphase separation phenomenon in polyelectrolyte melts and show that the same values of D as in the case of single chain collapse should be used, thus indicating universality of the model. Due to the charge correlation attraction, a long-range order in such melts can be observed even at zero Flory-Huggins parameter.

  19. Density functional theory for the description of charge-transfer processes at TTF/TCNQ interfaces

    KAUST Repository

    Van Regemorter, Tanguy

    2012-09-15

    In the field of organic electronics, a central issue is to assess how the frontier electronic levels of two adjacent organic layers align with respect to one another at the interface. This alignment can be driven by the presence of a partial charge transfer and the formation of an interface dipole; it plays a key role for instance in determining the rates of exciton dissociation or exciton formation in organic solar cells or light-emitting diodes, respectively. Reliably modeling the processes taking place at these interfaces remains a challenge for the computational chemistry community. Here, we review our recent theoretical work on the influence of the choice of density functional theory (DFT) methodology on the description of the charge-transfer character in the ground state of TTF/ TCNQ model complexes and interfaces. Starting with the electronic properties of the isolated TTF and TCNQ molecules and then considering the charge transfer and resulting interface dipole in TTF/TCNQ donor-acceptor stacks and bilayers, we examine the impact of the choice of DFT functional in describing the interfacial electronic structure. Finally, we employ computations based on periodic boundary conditions to highlight the impact of depolarization effects on the interfacial dipole moment. © Springer-Verlag 2012.

  20. In situ unravelling structural modulation across the charge-density-wave transition in vanadium disulfide.

    Science.gov (United States)

    Sun, Xu; Yao, Tao; Hu, Zhenpeng; Guo, Yuqiao; Liu, Qinghua; Wei, Shiqiang; Wu, Changzheng

    2015-05-28

    A deep understanding of the relationship between electronic and structure ordering across the charge-density-wave (CDW) transition is crucial for both fundamental study and technological applications. Herein, using in situ X-ray absorption fine structure (XAFS) spectroscopy coupled with high-resolution transmission electron microscopy (HRTEM), we have illustrated the atomic-level information on the local structural evolution across the CDW transition and its influence on the intrinsic electrical properties in VS2 system. The structure transformation, which is highlighted by the formation of vanadium trimers with derivation of V-V bond length (ΔR = 0.10 Å), was clearly observed across the CDW process. Moreover, the corresponding influence of lattice variation on the electronic behavior was clearly characterized by experimental results as well as theoretical analysis, which demonstrated that vanadium trimers drive the deformation of space charge density distribution into √3 ×√3 periodicity, with the conductivity of a1g band reducing by half. These observations directly unveiled the close connection between lattice evolution and electronic property variation, paving a new avenue for understanding the intrinsic nature of electron-lattice interactions in the VS2 system and other isostructural transition metal dichalcogenides across the CDW transition process.

  1. Surface electrochemical properties of red mud (bauxite residue): zeta potential and surface charge density.

    Science.gov (United States)

    Liu, Yanju; Naidu, Ravendra; Ming, Hui

    2013-03-15

    The surface electrochemical properties of red mud (bauxite residue) from different alumina refineries in Australia and China were studied by electrophoresis and measuring surface charge density obtained from acid/base potentiometric titrations. The electrophoretic properties were measured from zeta potentials obtained in the presence of 0.01 and 0.001 M KNO(3) over a wide pH range (3.5-10) by titration. The isoelectric point (IEP) values were found to vary from 6.35 to 8.70 for the red mud samples. Further investigation into the surface charge density of one sample (RRM) by acid/base potentiometric titration showed similar results for pH(PZC) with pH(IEP) obtained from electrokinetic measurements. The pH(IEP) determined from zeta potential measurements can be used as a characteristic property of red mud. The minerals contained in red mud contributed to the different values of pH(IEP) of samples obtained from different refineries. Different relationships of pH(IEP) with Al/Fe and Al/Si ratios (molar basis) were also found for different red mud samples.

  2. Superconductivity and Charge Density Wave in ZrTe3-xSex.

    Science.gov (United States)

    Zhu, Xiangde; Ning, Wei; Li, Lijun; Ling, Langsheng; Zhang, Ranran; Zhang, Jinglei; Wang, Kefeng; Liu, Yu; Pi, Li; Ma, Yongchang; Du, Haifeng; Tian, Minglian; Sun, Yuping; Petrovic, Cedomir; Zhang, Yuheng

    2016-06-02

    Charge density wave (CDW), the periodic modulation of the electronic charge density, will open a gap on the Fermi surface that commonly leads to decreased or vanishing conductivity. On the other hand superconductivity, a commonly believed competing order, features a Fermi surface gap that results in infinite conductivity. Here we report that superconductivity emerges upon Se doping in CDW conductor ZrTe3 when the long range CDW order is gradually suppressed. Superconducting critical temperature Tc(x) in ZrTe3-xSex (0 ≤ x ≤ 0.1) increases up to 4 K plateau for 0.04 ≤ x ≤ 0.07. Further increase in Se content results in diminishing Tc and filametary superconductivity. The CDW modes from Raman spectra are observed in x = 0.04 and 0.1 crystals, where signature of ZrTe3 CDW order in resistivity vanishes. The electronic-scattering for high Tc crystals is dominated by local CDW fluctuations at high temperatures, the resistivity is linear up to highest measured T = 300 K and contributes to substantial in-plane anisotropy.

  3. Characterization of the internal ion environment of biofilms based on charge density and shape of ion.

    Science.gov (United States)

    Kurniawan, Andi; Tsuchiya, Yuki; Eda, Shima; Morisaki, Hisao

    2015-12-01

    Biofilm polymers contain both electrically positively and negatively charged sites. These charged sites enable the biofilm to trap and retain ions leading to an important role of biofilm such as nutrient recycling and pollutant purification. Much work has focused on the ion-exchange capacity of biofilms, and they are known to adsorb ions through an exchange mechanism between the ions in solution and the ions adsorbed to the charged sites on the biofilm polymer. However, recent studies suggest that the adsorption/desorption behavior of ions in a biofilm cannot be explained solely by this ion exchange mechanism. To examine the possibility that a substantial amount of ions are held in the interstitial region of the biofilm polymer by an electrostatic interaction, intact biofilms formed in a natural environment were immersed in distilled water and ion desorption was investigated. All of the detected ion species were released from the biofilms over a short period of time, and very few ions were subsequently released over more time, indicating that the interstitial region of biofilm polymers is another ion reserve. The extent of ion retention in the interstitial region of biofilms for each ion can be determined largely by charge density, |Z|/r, where |Z| is the ion valence as absolute value and r is the ion radius. The higher |Z|/r value an ion has, the stronger it is retained in the interstitial region of biofilms. Ion shape is also a key determinant of ion retention. Spherical and non-spherical ions have different correlations between the condensation ratio and |Z|/r. The generality of these findings were assured by various biofilm samples. Thus, the internal regions of biofilms exchange ions dynamically with the outside environment.

  4. Calculation of polarization and bound charge density inside a dielectric material in triboelectric nanogenerators: Analytical and numerical study

    Science.gov (United States)

    Kim, SeongMin; Ha, Jaewook; Kim, Jin-Baek

    2016-11-01

    We analytically calculated polarization and bound charge density inside the dielectric material in metal-to-dielectric-mode triboelectric nanogenerators (TENG) where the transferred charges are collected on the bottom metal via electrostatic induction from the triboelectric charges that are generated by frictional contact. This bound charge density is associated with the surface density of states (DOS), overline{Ns(E)}. Two cases are considered here: i) for overline{Ns(E)} ≫ 1, it is calculated that the bound charge density is proportional to the dielectric constant and the work function difference between the two materials, but inversely proportional to the thickness of the dielectric material (ɛ0(ɛ2-1) (E0-W)/e \\cdot d2); ii) for overline{Ns(E)} ≪ 1 with constant overline{Ns(E)}, the bound charge density is mostly proportional to the work function difference between the materials, and inversely proportional to the thickness of the dielectric material ((ɛ2-1)x/d_{2+\\varepsilon2\\cdot x} \\cdot Ns(E)\\cdot e\\cdot (E0-W)).

  5. Adsorption of weak polyelectrolytes on charged nanoparticles. Impact of salt valency, pH, and nanoparticle charge density. Monte Carlo simulations.

    Science.gov (United States)

    Carnal, Fabrice; Stoll, Serge

    2011-10-27

    Complex formation between a weak flexible polyelectrolyte chain and one positively charged nanoparticle in presence of explicit counterions and salt particles is investigated using Monte Carlo simulations. The influence of parameters such as the nanoparticle surface charge density, salt valency, and solution property such as the pH on the chain protonation/deprotonation process and monomer adsorption at the nanoparticle surface are systematically investigated. It is shown that the nanoparticle presence significantly modifies chain acid/base and polyelectrolyte conformational properties. The importance of the attractive electrostatic interactions between the chain and the nanoparticle clearly promotes the chain deprotonation leading, at high pH and nanoparticle charge density, to fully wrapped polyelectrolyte at the nanoparticle surface. When the nanoparticle bare charge is overcompensated by the polyelectrolyte charges, counterions and salt particles condense at the surface of the polyelectrolyte-nanoparticle complex to compensate for the excess of charges providing from the adsorbed polyelectrolyte chain. It is also shown that the complex formation is significantly affected by the salt valency. Indeed, with the presence of trivalent salt cations, competition is observed between the nanoparticle and the trivalent cations. As a result, the amount of adsorbed monomers is less important than in the monovalent and divalent case and chain conformations are different due to the collapse of polyelectrolyte segments around trivalent cations out of the nanoparticle adsorption layer.

  6. Experimental charge-density studies: data reduction and model quality: the more the better?

    Science.gov (United States)

    Herbst-Irmer, Regine; Stalke, Dietmar

    2017-08-01

    In this review, recent developments concerning data and model quality in experimental charge-density investigations from a personal view-point are described. Data quality is not only achieved by the high resolution, high I/σ(I) values, low merging R values and high multiplicity. The quality of the innermost reflections especially is crucial for mapping the density distribution of the outermost valence electrons and can be monitored by (I/σ)(asymptotic). New detector technologies seem to be promising improvements. Empirical corrections to correct for low-energy contamination of mirror-focused X-ray data and for resolution- and temperature-dependent errors caused by factors such as thermal diffuse scattering are described. Shashlik-like residual density patterns can indicate the need for an anharmonic description of the thermal motion of individual atoms. The physical reliability of the derived model must be thoroughly analysed. The derived probability density functions for the mean-squared atomic vibrational displacements especially should have only small negative values. The treatment of H atoms has been improved by methods to estimate anisotropic thermal motion. For very high resolution data, the polarization of the core density cannot be neglected. Several tools to detect systematic errors are described. A validation tool is presented that easily detects when the refinement of additional parameters yields a real improvement in the model or simply overfits the given data. In all investigated structures, it is proved that the multipole parameters of atoms with a comparable chemical environment should be constrained to be identical. The use of restraints could be a promising alternative.

  7. On the Control of the Fixed Charge Densities in Al2O3-Based Silicon Surface Passivation Schemes.

    Science.gov (United States)

    Simon, Daniel K; Jordan, Paul M; Mikolajick, Thomas; Dirnstorfer, Ingo

    2015-12-30

    A controlled field-effect passivation by a well-defined density of fixed charges is crucial for modern solar cell surface passivation schemes. Al2O3 nanolayers grown by atomic layer deposition contain negative fixed charges. Electrical measurements on slant-etched layers reveal that these charges are located within a 1 nm distance to the interface with the Si substrate. When inserting additional interface layers, the fixed charge density can be continuously adjusted from 3.5 × 10(12) cm(-2) (negative polarity) to 0.0 and up to 4.0 × 10(12) cm(-2) (positive polarity). A HfO2 interface layer of one or more monolayers reduces the negative fixed charges in Al2O3 to zero. The role of HfO2 is described as an inert spacer controlling the distance between Al2O3 and the Si substrate. It is suggested that this spacer alters the nonstoichiometric initial Al2O3 growth regime, which is responsible for the charge formation. On the basis of this charge-free HfO2/Al2O3 stack, negative or positive fixed charges can be formed by introducing additional thin Al2O3 or SiO2 layers between the Si substrate and this HfO2/Al2O3 capping layer. All stacks provide very good passivation of the silicon surface. The measured effective carrier lifetimes are between 1 and 30 ms. This charge control in Al2O3 nanolayers allows the construction of zero-fixed-charge passivation layers as well as layers with tailored fixed charge densities for future solar cell concepts and other field-effect based devices.

  8. Density-functional theory for fluid mixtures of charged chain particles and spherical counterions in contact with charged hard wall: Adsorption, double layer capacitance, and the point of zero charge.

    Science.gov (United States)

    Pizio, O; Bucior, K; Patrykiejew, A; Sokołowski, S

    2005-12-01

    We consider a density-functional theory to describe nonuniform fluids composed of chain molecules, containing a charged segment each, and spherical counterions. The chain molecules are modeled as freely jointed chains of hard spheres, the counterions are oppositely charged spheres of the same diameter as all segments of chain molecules. The theory is applied to study the structure of adsorbed layers, the excess adsorption isotherms, the capacitance of the double layer, and the potential of the zero charge. We show that all electric properties are strongly dependent on the length of the chain molecules. Moreover, these properties are also dependent on the position of the charged segment in the chain.

  9. Management of deep brain stimulator battery failure: battery estimators, charge density, and importance of clinical symptoms.

    Directory of Open Access Journals (Sweden)

    Kaihan Fakhar

    Full Text Available OBJECTIVE: We aimed in this investigation to study deep brain stimulation (DBS battery drain with special attention directed toward patient symptoms prior to and following battery replacement. BACKGROUND: Previously our group developed web-based calculators and smart phone applications to estimate DBS battery life (http://mdc.mbi.ufl.edu/surgery/dbs-battery-estimator. METHODS: A cohort of 320 patients undergoing DBS battery replacement from 2002-2012 were included in an IRB approved study. Statistical analysis was performed using SPSS 20.0 (IBM, Armonk, NY. RESULTS: The mean charge density for treatment of Parkinson's disease was 7.2 µC/cm(2/phase (SD = 3.82, for dystonia was 17.5 µC/cm(2/phase (SD = 8.53, for essential tremor was 8.3 µC/cm(2/phase (SD = 4.85, and for OCD was 18.0 µC/cm(2/phase (SD = 4.35. There was a significant relationship between charge density and battery life (r = -.59, p<.001, as well as total power and battery life (r = -.64, p<.001. The UF estimator (r = .67, p<.001 and the Medtronic helpline (r = .74, p<.001 predictions of battery life were significantly positively associated with actual battery life. Battery status indicators on Soletra and Kinetra were poor predictors of battery life. In 38 cases, the symptoms improved following a battery change, suggesting that the neurostimulator was likely responsible for symptom worsening. For these cases, both the UF estimator and the Medtronic helpline were significantly correlated with battery life (r = .65 and r = .70, respectively, both p<.001. CONCLUSIONS: Battery estimations, charge density, total power and clinical symptoms were important factors. The observation of clinical worsening that was rescued following neurostimulator replacement reinforces the notion that changes in clinical symptoms can be associated with battery drain.

  10. Superconductivity in the charge-density-wave state of the organic metal α- (BEDT-TTF)2 KHg (SCN)4

    Science.gov (United States)

    Andres, D.; Kartsovnik, M. V.; Biberacher, W.; Neumaier, K.; Schuberth, E.; Müller, H.

    2005-11-01

    The superconducting transition in the layered organic compound α-(BEDT-TTF)2KHg(SCN)4 has been studied in the two hydrostatic pressure regimes where a charge-density wave is either present or completely suppressed. Within the charge-density-wave state the experimental results reveal a network of weakly coupled superconducting regions. This is especially seen in a strong enhancement of the measured critical field and the corresponding positive curvature of its temperature dependence. Further, it is shown that on lowering the pressure into the density-wave state traces of a superconducting phase already start to appear at a much higher temperature.

  11. Thermodynamic and critical properties of the charge density wave system ErTe3

    Science.gov (United States)

    Saint-Paul, M.; Remenyi, G.; Guttin, C.; Lejay, P.; Monceau, P.

    2017-01-01

    We present specific heat and ultrasonic measurements on the rare earth tritelluride ErTe3 compound. Thermodynamic anomalies are observed at the upper charge density wave (CDW) phase transition TCDW1=265 K and the second one at TCDW2=155 K. Similar critical behaviors are found at both CDW phase transitions and that we tentatively described in terms of the 3D XY model. Different anisotropic stress dependences ∂TCDW1 / ∂σii and ∂TCDW2 / ∂σii are found at the two successive CDW phase transitions. Magnitude of the elastic constant anomalies at TCDW2 is ten times smaller than that at TCDW1. Anomalies in the elastic constants at the upper CDW TCDW1 exhibit two dimensional features in the layer planes while in contrast a three dimensional behavior is observed at TCDW2.

  12. $\\eta^\\prime$ meson mass from topological charge density correlator in QCD

    CERN Document Server

    Fukaya, H; Cossu, G; Hashimoto, S; Kaneko, T; Noaki, J

    2015-01-01

    The flavor-singlet component of the eta prime meson is related to the topological structure of the SU(3) gauge field through the chiral anomaly. We perform a 2+1-flavor lattice QCD calculation and demonstrate that the two-point function of a gluonically defined topological charge density after a short Yang-Mills gradient flow contains the propagation of the eta prime meson, by showing that its mass in the chiral and continuum limit is consistent with the experimental value. The gluonic correlator does not suffer from the contamination of the pion contribution, and the clean signal is obtained at significantly lower numerical cost compared to the conventional method with the quark bilinear operators.

  13. Finite-size effects in quasi-one-dimensional conductors with a charge-density wave

    Energy Technology Data Exchange (ETDEWEB)

    Zaitsev-Zotov, Sergei V [Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Moscow (Russian Federation)

    2004-06-30

    Recent studies of finite-size effects in charge-density wave conductors are reviewed. Various manifestations of finite-size effects, including the transverse-size dependence of the nonlinear-conduction threshold field, the Peierls transition temperature, high-frequency conduction, and the relaxation rates of metastable states, are discussed. Resistivity jumps in thin samples, the smeared threshold field for nonlinear conduction, and threshold conduction above the Peierls transition temperature are considered, as are mesoscopic oscillations of the threshold field, one-dimensional conduction in thin crystals, absolute negative conductivity of quasi-one-dimensional conductors, the length dependence of the phase-slip voltage, and the Aharonov-Bohm oscillations in sliding CDWs. Problems yet to be solved are discussed. (reviews of topical problems)

  14. Charge density A probe for the nuclear interaction in microscopic transport models

    CERN Document Server

    Galíchet, E; Lecolley, J F; Bougault, R; Butà, A; Colin, J; Cussol, D; Durand, D; Guinet, D; Lautesse, P; Rivet, M F; Borderie, B; Auger, G; Bouriquet, B; Chbihi, A; Frankland, J D; Guiot, B; Hudan, S; Charvet, J L; Dayras, R; Lavaud, F; Neindre, N L; López, O; Manduci, L; Marie, J; Nalpas, L; Normand, J; Pârlog, M; Pawlowski, P; Plagnol, E; Rosato, E; Steckmeyer, J C; Tamain, B; Lauwe, A V; Vient, E; Volant, C; Wieleczko, J P

    2003-01-01

    The transport properties of the sup 3 sup 6 Ar+ sup 5 sup 8 Ni system at 95 A .MeV measured with the INDRA array, are studied within the BNV kinetic equation. A general protocol of comparison between the N-body experimental fragment information and the one-body distribution function is developed using global variables, with a special focus on charge density. This procedure avoids any definition of sources and any use of an afterburner in the simulation. We shall discuss the feasibility of such an approach and the distortions induced by the finite detection efficiency and the completeness requirements of the data selection. The sensitivity of the different global observables to the macroscopic parameters of the effective nuclear interaction will be studied in detail.

  15. Possibility of charge density wave transition in a SrPt2Sb2 superconductor.

    Science.gov (United States)

    Ibuka, Soshi; Imai, Motoharu

    2016-04-27

    The first-order transition at T(0) =  270 K for the platinum-based SrPt2Sb2 superconductor was investigated using x-ray diffraction and magnetic susceptibility measurements. When polycrystalline SrPt2Sb2 was cooled down through T(0), the structure was transformed from monoclinic to a modulated orthorhombic structure, and no magnetic order was formed, which illustrates the possibility of a charge density wave (CDW) transition at T(0). SrPt2Sb2 can thus be a new example to examine the interplay of CDW and superconductivity in addition to SrPt2As2, BaPt2As2, and LaPt2Si2. It is unique that the average structure of the low-temperature phase has higher symmetry than that of the high-temperature phase.

  16. First measurements of charge carrier density and mobility of in-situ enriched 28Si

    Science.gov (United States)

    Ramanayaka, A. N.; Dwyer, K. J.; Kim, Hyun-Soo; Stewart, M. D., Jr.; Pomeroy, J. M.

    Magnetotransport in top gated Hall bar devices is investigated to characterize the electrical properties of in-situ enriched 28Si. Isotopically enriched 28Si is an ideal candidate for quantum information processing devices as the elimination of unpaired nuclear spins improves the fidelity of the quantum information. Using mass filtered ion beam deposition we, in-situ, enrich and deposit epitaxial 28Si, achieving several orders of magnitude better enrichment compared to other techniques. In order to explore the electrical properties and optimize the growth conditions of in-situ enriched 28Si we perform magnetotransport measurements on top gated Hall bar devices at temperatures ranging from 300 K to cryogenic temperatures and at moderate magnetic fields. Here, we report on the charge carrier density and mobility extracted from such experiments, and will be compared among different growth conditions of in-situ enriched 28Si.

  17. Non-thermal separation of electronic and structural orders in a persisting charge density wave

    CERN Document Server

    Porer, M; Ménard, J -M; Dachraoui, H; Mouchliadis, L; Perakis, I E; Heinzmann, U; Demsar, J; Rossnagel, K; Huber, R

    2016-01-01

    The simultaneous ordering of different degrees of freedom in complex materials undergoing spontaneous symmetry-breaking transitions often involves intricate couplings that have remained elusive in phenomena as wide ranging as stripe formation, unconventional superconductivity or colossal magnetoresistance. Ultrafast optical, x-ray and electron pulses can elucidate the microscopic interplay between these orders by probing the electronic and lattice dynamics separately, but a simultaneous direct observation of multiple orders on the femtosecond scale has been challenging. Here we show that ultrabroadband terahertz pulses can simultaneously trace the ultrafast evolution of coexisting lattice and electronic orders. For the example of a charge-density-wave (CDW) in 1T-TiSe2, we demonstrate that two components of the CDW order parameter - excitonic correlations and a periodic lattice distortion (PLD) - respond very differently to 12-fs optical excitation. Even when the excitonic order of the CDW is quenched, the PL...

  18. Fermi Surface Evolution Across Multiple Charge Density Wave Transitions in ErTe3

    Energy Technology Data Exchange (ETDEWEB)

    Moore, R.G.; /SLAC, SSRL /Stanford U., Geballe Lab.; Brouet, V.; /Orsay, LPS; He, R.; /SLAC, SSRL /Stanford U., Geballe Lab.; Lu, D.H.; /SLAC, SSRL; Ru, N.; Chu, J.-H.; Fisher, I.R.; /Stanford U., Geballe Lab.; Shen, Z.-X.; /SLAC, SSRL /Stanford U., Geballe Lab.

    2010-02-15

    The Fermi surface (FS) of ErTe{sub 3} is investigated using angle-resolved photoemission spectroscopy (ARPES). Low temperature measurements reveal two incommensurate charge density wave (CDW) gaps created by perpendicular FS nesting vectors. A large {Delta}{sub 1} = 175 meV gap arising from a CDW with c* - q{sub CDW1} {approx} 0.70(0)c* is in good agreement with the expected value. A second, smaller {Delta}{sub 2} = 50 meV gap is due to a second CDW with a* - q{sub CDW2} {approx} 0.68(5)a*. The temperature dependence of the FS, the two gaps and possible interaction between the CDWs are examined.

  19. Spin-charge and spin-orbital separations in density-functional theory

    CERN Document Server

    Vieira, Daniel

    2012-01-01

    It is known that the separation of electrons into spinons and chargons, the spin-charge separation, plays a decisive role when describing strongly correlated one-dimensional (1D) Friedel oscillations. Here, we extend the investigation by considering a third electron fractionalization: the separation into spinons and orbitons. Specifically, we deal with two exact constraints of exchange-correlation (XC) density-functionals: (i) The constancy of the highest occupied Kohn-Sham eigenvalues upon fractional electron numbers, and (ii) their discontinuities at integers. By means of 1D Hubbard chains, we show that spin-orbital separation can be decisive when dealing with derivative discontinuities of XC potentials, especially at strong correlations.

  20. Determination of surface charge density of α-alumina by acid-base titration

    Directory of Open Access Journals (Sweden)

    Justin W. Ntalikwa

    2007-04-01

    Full Text Available The surface charge density (σo of colloidal alpha alumina suspended in various 1:1 electrolytes was measured using acid-base titration. An autotitrator capable of dispensing accurately 25 plus or minus 0.1 μL of titrant was used. The pH and temperature in the titration cell were monitored using single junction electrodes and platinum resistance thermometers, respectively. A constant supply of nitrogen gas in the cell was used to maintain inert conditions. The whole set up was interfaced with a computer for easy data acquisition. It was observed that the material exhibits a point of zero charge (PZC, this occurred at pH of 7.8 plus or minus 0.1, 7.6 plus or minus 0.2, 8.5 plus or minus 0.1, 8.3 plus or minus 0.1 for NaCl, NaNO3, CsCl and CsNO3 systems, respectively. It was also observed that below PZC, σo increases with increase in electrolyte concentration (Co whereas above PZC, σo decreases with increase in Co. It was concluded that σo of this material is a function of pH and Co and that its polarity can be varied through zero by varying these parameters.

  1. Phase transitions to dipolar clusters and charge density waves in high T{sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Saarela, M., E-mail: Mikko.Saarela@oulu.fi [Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 (Finland); Kusmartsev, F.V. [Department of Physics, Loughborough University, LE11 3TU (United Kingdom)

    2017-02-15

    We show that doping of hole charge carriers leads to formation of electric dipolar clusters in cuprates. They are created by many-body interactions between the dopant ion outside and holes inside the CuO planes. Because of the two-fold degeneracy holes in the CuO plane cluster into four-particles resonance valence bond plaquettes bound with dopant ions. Such dipoles may order into charge-density waves (CDW) or stripes or form a disordered state depending on doping and temperature. The lowest energy of the ordered system corresponds to a local anti-ferroelectric ordering. The mobility of individual disordered dipoles is very low at low temperatures and they prefer first to bind into dipole-dipole pairs. Electromagnetic radiation interacts strongly with electric dipoles and when the sample is subjected to it the mobility changes significantly. This leads to a fractal growth of dipolar clusters. The existence of electric dipoles and CDW induce two phase transitions with increasing temperature, melting of the ordered state and disappearance of the dipolar state. Ferroelectricity at low doping is a natural consequence of such dipole moments. We develop a theory based on two-level systems and dipole-dipole interaction to explain the behavior of the polarization as a function of temperature and electric field.

  2. Central depressions in the charge density profiles of the nuclei around $^{46}$Ar

    CERN Document Server

    Song, Jun Ling; Long, Wen Hui

    2015-01-01

    The occurrence of the proton bubble-like structure has been studied within the relativistic Hartree-Fock-Bogoliubov (RHFB) and relativistic Hartree-Bogoliubov (RHB) theories by exploring the bulk properties, the charge density profiles and single proton spectra of argon isotopes and $N = 28$ isotones. It is found that the RHFB calculations with PKA1 effective interaction, which can properly reproduce the charge radii of argon isotopes and the $Z=16$ proton shell nearby, do not support the occurrence of the proton bubble-like structure in argon isotopes due to the prediction of deeper bound proton orbit $\\pi2s_{1/2}$ than $\\pi1d_{3/2}$. For $N = 28$ isotones, $^{42}$Si and $^{40}$Mg are predicted by both RHFB and RHB models to have the proton bubble-like structure, owing to the large gap between the proton $\\pi2s_{1/2}$ and $\\pi1d_{5/2}$ orbits, namely the $Z=14$ proton shell. Therefore, $^{42}$Si is proposed as the potential candidate of proton bubble nucleus, which has longer life-time than $^{40}$Mg.

  3. Phase transitions to dipolar clusters and charge density waves in high Tc superconductors

    Science.gov (United States)

    Saarela, M.; Kusmartsev, F. V.

    2017-02-01

    We show that doping of hole charge carriers leads to formation of electric dipolar clusters in cuprates. They are created by many-body interactions between the dopant ion outside and holes inside the CuO planes. Because of the two-fold degeneracy holes in the CuO plane cluster into four-particles resonance valence bond plaquettes bound with dopant ions. Such dipoles may order into charge-density waves (CDW) or stripes or form a disordered state depending on doping and temperature. The lowest energy of the ordered system corresponds to a local anti-ferroelectric ordering. The mobility of individual disordered dipoles is very low at low temperatures and they prefer first to bind into dipole-dipole pairs. Electromagnetic radiation interacts strongly with electric dipoles and when the sample is subjected to it the mobility changes significantly. This leads to a fractal growth of dipolar clusters. The existence of electric dipoles and CDW induce two phase transitions with increasing temperature, melting of the ordered state and disappearance of the dipolar state. Ferroelectricity at low doping is a natural consequence of such dipole moments. We develop a theory based on two-level systems and dipole-dipole interaction to explain the behavior of the polarization as a function of temperature and electric field.

  4. The amplitudes and the structure of the charge density wave in YBCO

    Science.gov (United States)

    Kharkov, Y. A.; Sushkov, O. P.

    2016-10-01

    We find unknown s- and d-wave amplitudes of the recently discovered charge density wave (CDW) in underdoped cuprates. To do so we perform a combined analysis of experimental data for ortho-II YBa2Cu3Oy. The analysis includes data on nuclear magnetic resonance, resonant inelastic X-ray scattering, and hard X-ray diffraction. The amplitude of doping modulation found in our analysis is 3.5 · 10‑3 in a low magnetic field and T = 60 K, the amplitude is 6.5 · 10‑3 in a magnetic field of 30T and T = 1.3 K. The values are in units of elementary charge per unit cell of a CuO2 plane. We show that the data rule out a checkerboard pattern, and we also show that the data might rule out mechanisms of the CDW which do not include phonons.

  5. High-resolution synchrotron data collection for charge-density work at 100 and 20 K.

    Science.gov (United States)

    Luger, Peter; Messerschmidt, Marc; Scheins, Stephan; Wagner, Armin

    2004-09-01

    For the measurement of very accurate high-resolution X-ray data for charge-density work, synchrotron beamlines provide a bright radiation source of outstanding properties. Most important are the very high primary intensity and the possibility of choosing hard radiation with lambda approximately 0.5 A or even shorter. This together with area detection and a stable low-temperature device means that accurate and large data sets can be measured in a short time. A number of data collections are reported, which were carried out at the beamlines F1 and D3 of Hasylab (DESY, Hamburg) first at 100 K and later at 15-20 K, demonstrating the quality of the measured intensities. A low temperature of around 20 K was obtained at beamline D3 with a double-stage closed-cycle helium cryostat where the standard beryllium cylinder of the vacuum chamber was replaced by a 0.1 mm Kapton film. Comparison of different data sets measured for a strychnine crystal demonstrated how I/sigma ratios favorably improve if synchrotron radiation at a low temperature of 15 K was used. Synchrotron-based studies on several biologically active compounds are briefly summarized and a synchrotron experiment of an otherwise not sufficiently diffracting crystal of a tetraphenyl barbaralane derivative is described in detail. Atomic volumes and charges of a highly substituted C(60) fullerene are reported derived from a synchrotron data set of more than 350000 reflections.

  6. Structure-dependent charge density as a determinant of antimicrobial activity of peptide analogues of defensin.

    Science.gov (United States)

    Bai, Yang; Liu, Shouping; Jiang, Ping; Zhou, Lei; Li, Jing; Tang, Charles; Verma, Chandra; Mu, Yuguang; Beuerman, Roger W; Pervushin, Konstantin

    2009-08-01

    Defensins are small (3-5 kDa) cysteine-rich cationic proteins found in both vertebrates and invertebrates constituting the front line of host innate immunity. Despite intensive research, bactericidal and cytotoxic mechanisms of defensins are still largely unknown. Moreover, we recently demonstrated that small peptides derived from defensins are even more potent bactericidal agents with less toxicity toward host cells. In this paper, structures of three C-terminal (R36-K45) analogues of human beta-defensin-3 were studied by 1H NMR spectroscopy and extensive molecular dynamics simulations. Because of indications that these peptides might target the inner bacterial membrane, they were reconstituted in dodecylphosphocholine or dodecylphosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] mixed micelles, and lipid bicelles mimicking the phospholipid-constituted bilayer membrane of mammalian and bacterial cells. The results show that the binding affinity and partitioning into the lipid phase and the ability to dimerize and accrete well-defined structures upon interactions with lipid membranes contribute to compactization of positive charges within peptide oligomers. The peptide charge density, mediated by corresponding three-dimensional structures, was found to directly correlate with the antimicrobial activity. These novel observations may provide a new rationale for the design of improved antimicrobial agents.

  7. Monodisperse TiO2 Spheres with High Charge Density and Their Self-Assembly.

    Science.gov (United States)

    Xia, Hongbo; Wu, Suli; Su, Xin; Zhang, Shufen

    2017-01-03

    Titanium dioxide (TiO2 ) spheres are potential candidates to fabricate three-dimensional (3D) photonic crystals owing to their high refractive index and low absorption in the visible and near-infrared regions. Here, TiO2 spheres with both high surface charge density and uniform size, which are necessary for the self-assembly of TiO2 spheres, have been prepared by means of sol-gel methods in ethanol in the presence of thioglycolic acid as ligand. Thioglycolic acid, which contains two functional groups, not only acts as coordinating ligand for stabilizing and controlling the growth of TiO2 spheres but also endows the resulting TiO2 spheres with high charge density as based on ζ-potential analysis when the pH of the TiO2 aqueous dispersion was 6.5 or higher. The SEM images illustrate that the diameter of the prepared TiO2 spheres can be tuned from 100 to 300 nm by simply controlling the concentration of H2 O. FTIR spectra confirm that thioglycolic acid bonded to the surface of TiO2 spheres through carboxylic groups. As anticipated, the obtained TiO2 spheres could self-assemble to form a 3D opal photonic crystal structure by means of a simple gravity sedimentation method. Then the TiO2 spheres in the 3D opal photonic crystal structure were able to transform into a pure anatase phase by annealing at different temperatures.

  8. Calculations of current densities for neutral and doubly charged persubstituted benzenes using effective core potentials.

    Science.gov (United States)

    Rauhalahti, Markus; Taubert, Stefan; Sundholm, Dage; Liégeois, Vincent

    2017-03-08

    Magnetically induced current density susceptibilities and ring-current strengths have been calculated for neutral and doubly charged persubstituted benzenes C6X6 and C6X6(2+) with X = F, Cl, Br, I, At, SeH, SeMe, TeH, TeMe, and SbH2. The current densities have been calculated using the gauge-including magnetically induced current (GIMIC) method, which has been interfaced to the Gaussian electronic structure code rendering current density calculations using effective core potentials (ECP) feasible. Relativistic effects on the ring-current strengths have been assessed by employing ECP calculations of the current densities. Comparison of the ring-current strengths obtained in calculations on C6At6 and C6At6(2+) using relativistic and non-relativistic ECPs show that scalar relativistic effects have only a small influence on the ring-current strengths. Comparisons of the ring-current strengths and ring-current profiles show that the C6I6(2+), C6At6(2+), C6(SeH)6(2+), C6(SeMe)6(2+), C6(TeH)6(2+), C6(TeMe)6(2+), and C6(SbH2)6(2+) dications are doubly aromatic sustaining spatially separated ring currents in the carbon ring and in the exterior of the molecule. The C6I6(+) radical cation is also found to be doubly aromatic with a weaker ring current than obtained for the dication.

  9. Influence of nitrogen dose on the charge density of nitrogen-implanted buried oxide in SOI wafers

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Zhongshan [Department of Physics, University of Jinan, Jinan 250022 (China); Liu Zhongli; Li Ning; Li Guohua [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Zhang Enxia, E-mail: ss_zhengzs@ujn.edu.c [College of Material Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)

    2010-02-15

    To harden silicon-on-insulator (SOI) wafers fabricated using separation by implanted oxygen (SIMOX) to total-dose irradiation, the technique of nitrogen implantation into the buried oxide (BOX) layer of SIMOX wafers can be used. However, in this work, it has been found that all the nitrogen-implanted BOX layers reveal greater initial positive charge densities, which increased with increasing nitrogen implantation dose. Also, the results indicate that excessively large nitrogen implantation dose reduced the radiation tolerance of BOX for its high initial positive charge density. The bigger initial positive charge densities can be ascribed to the accumulation of implanted nitrogen near the Si-BOX interface after annealing. On the other hand, in our work, it has also been observed that, unlike nitrogen-implanted BOX, all the fluorine-implanted BOX layers show a negative charge density. To obtain the initial charge densities of the BOX layers, the tested samples were fabricated with a metal-BOX-silicon (MBS) structure based on SIMOX wafers for high-frequency capacitance-voltage (C-V) analysis. (semiconductor technology)

  10. First principles study on the charge density and the bulk modulus of the transition metals and their carbides and nitrides

    Institute of Scientific and Technical Information of China (English)

    Li Cheng-Bin; Li Ming-Kai; Yin Dong; Liu Fu-Qing; Fan Xiang-Jun

    2005-01-01

    A first principles study of the electronic properties and bulk modulus (B0) of the fcc and bcc transition metals,transition metal carbides and nitrides is presented. The calculations were performed by plane-wave pseudopotential method in the framework of the density functional theory with local density approximation. The density of states and the valence charge densities of these solids are plotted. The results show that B0 does not vary monotonically when the number of the valence d electrons increases. B0 reaches a maximum and then decreases for each of the four sorts of solids. It is related to the occupation of the bonding and anti-bonding states in the solid. The value of the valence charge density at the midpoint between the two nearest metal atoms tends to be proportional to B0.

  11. Charge-Density-Excitation Spectrum in the t-t'-J-V Model

    Science.gov (United States)

    Greco, Andrés; Yamase, Hiroyuki; Bejas, Matías

    2017-03-01

    We study the density-density correlation function in a large-N scheme of the t-t'-J-V model. When the nearest-neighbor Coulomb interaction V is zero, our model exhibits phase separation in a wide doping region and we obtain large spectral weight near momentum q = (0,0) at low energy, which originates from the proximity to phase separation. These features are much stronger for electron doping than for hole doping. However, once phase separation is suppressed by including a finite V, the low-energy spectral weight around q = (0,0) is substantially suppressed. Instead a sharp zero-sound mode is stabilized above the particle-hole continuum. We discuss that the presence of a moderate value of V, which is frequently neglected in the t-J model, is important to understand low-energy charge excitations especially close to q = (0,0) for electron doping. This insight should be taken into account in a future study of x-ray scattering measurements.

  12. Comparison of volumetric bone mineral density in the operated and contralateral knee after anterior cruciate ligament and reconstruction: A 1-year follow-up study using peripheral quantitative computed tomography.

    Science.gov (United States)

    Mündermann, Annegret; Payer, Nina; Felmet, Gernot; Riehle, Hartmut

    2015-12-01

    The purpose of this study was to quantify changes in volumetric bone mineral density (vBMD) in the tibial plateau of the operated and contralateral leg measured using peripheral quantitative computed tomography (pQCT) before and 3, 6, and 12 months after anterior cruciate ligament (ACL) reconstruction. The ACL was reconstructed with a hamstring tendon autograft using press-fit fixation. pQCT measurements of the proximal tibia were obtained in 61 patients after ACL reconstruction, and total, cortical, and trabecular vBMD were calculated. vBMD in the operated leg decreased from baseline to 3 months (-12% [total], -11% [cortical], and -12.6% [trabecular]; preconstruction contributed to loss in bone mineral density within the first year after surgery. The role of factors such as time of weight-bearing, joint mechanics, post-traumatic inflammatory reactions, or genetic predisposition in modulating the development of posttraumatic knee osteoarthritis after ACL injury should be further elucidated.

  13. Incorrect diatomic dissociation in variational reduced density matrix theory arises from the flawed description of fractionally charged atoms.

    Science.gov (United States)

    Van Aggelen, Helen; Bultinck, Patrick; Verstichel, Brecht; Van Neck, Dimitri; Ayers, Paul W

    2009-07-21

    The behaviour of diatomic molecules is examined using the variational second-order density matrix method under the P, Q and G conditions. It is found that the method describes the dissociation limit incorrectly, with fractional charges on the well-separated atoms. This can be traced back to the behaviour of the energy versus the number of electrons for the isolated atoms. It is shown that the energies for fractional charges are much too low.

  14. Linear and angular momentum of electromagnetic fields generated by an arbitrary distribution of charge and current densities at rest

    CERN Document Server

    Thidé, B; Then, H; Tamburini, F

    2010-01-01

    Starting from Stratton-Panofsky-Phillips-Jefimenko equations for the electric and magnetic fields generated by completely arbitrary charge and current density distributions at rest, we derive far-zone approximations for the fields, containing all components, dominant as well as sub-dominant. Using these approximate formulas, we derive general formulas for the total electromagnetic linear momentum and angular momentum, valid at large distances from arbitrary, non-moving charge and current sources.

  15. Evidence for a Peierls phase-transition in a three-dimensional multiple charge-density waves solid.

    Science.gov (United States)

    Mansart, Barbara; Cottet, Mathieu J G; Penfold, Thomas J; Dugdale, Stephen B; Tediosi, Riccardo; Chergui, Majed; Carbone, Fabrizio

    2012-04-10

    The effect of dimensionality on materials properties has become strikingly evident with the recent discovery of graphene. Charge ordering phenomena can be induced in one dimension by periodic distortions of a material's crystal structure, termed Peierls ordering transition. Charge-density waves can also be induced in solids by strong coulomb repulsion between carriers, and at the extreme limit, Wigner predicted that crystallization itself can be induced in an electrons gas in free space close to the absolute zero of temperature. Similar phenomena are observed also in higher dimensions, but the microscopic description of the corresponding phase transition is often controversial, and remains an open field of research for fundamental physics. Here, we photoinduce the melting of the charge ordering in a complex three-dimensional solid and monitor the consequent charge redistribution by probing the optical response over a broad spectral range with ultrashort laser pulses. Although the photoinduced electronic temperature far exceeds the critical value, the charge-density wave is preserved until the lattice is sufficiently distorted to induce the phase transition. Combining this result with ab initio electronic structure calculations, we identified the Peierls origin of multiple charge-density waves in a three-dimensional system for the first time.

  16. Transport studies of ions across polystyrene based composite membrane: Evaluation of fixed charge density using theoretical models

    Science.gov (United States)

    Imteyaz, Shahla; Rafiuddin

    2016-11-01

    Polystyrene (PS) dispersed tin molybdate (TM) composite was prepared by sol-gel method. The membrane was characterized for its thermal stability by TG-DTA. SEM reveals the formation of composite material with uniform surface morphology. Crystallinity and phosphorylation of the membrane was confirmed by X-RD and FT-IR. Membrane potential of different monovalent electrolytes with varying concentration followed the order LiCl > NaCl > NH4Cl > KCl. Membrane potential increases with dilution of electrolytes confirming it to be cation selective in nature. The theoretical value of fixed charge density for the membrane was also evaluated from membrane potential using different approaches proposed by (a) Teorell-Meyer-Sievers (b) Kobatake and (c) Nagasawa, which are comparable with the experimental values. Fixed charge density examined for the electrolytes follows the order LiCl > NaCl > NH4Cl > KCl. Li+ ion shows highest value of fixed charge density in all the methods as the Donnan exclusion is highest for the electrolyte of smaller cation size. Transport number and mobility ratio for ion selectivity also increases with dilution. Membrane shows the lowest permselectivity for K+ while highest for Li+. The strong binding affinity of K+ counter-ion with fixed charge groups on the polymer decreases the membrane charge density and permselectivity. Thus, the membrane shows its applicability in various electro-membrane processes.

  17. Small scale density variations of electrons and charged particles in the vicinity of polar mesosphere summer echoes

    Directory of Open Access Journals (Sweden)

    M. Rapp

    2003-01-01

    Full Text Available We present small scale variations of electron number densities and particle charge number densities measured in situ in the presence of polar mesosphere summer echoes. It turns out that the small scale fluctuations of electrons and negatively charged particles show a strong anticorrelation down to the smallest scales observed. Comparing these small scale structures with the simultaneously measured radar signal to noise profile, we find that the radar profile is well described by the power spectral density of both electrons and charged particles at the radar half wavelength (=the Bragg scale. Finally, we consider the shape of the power spectra of the observed plasma fluctuations and find that both charged particles and electrons show spectra that can be explained in terms of either neutral air turbulence acting on the distribution of a low diffusivity tracer or the fossil remnants of a formerly active turbulent region. All these results are consistent with the theoretical ideas by Rapp and Lübken (2003 suggesting that PMSE can be explained by a combination of active and fossil neutral air turbulence acting on the large and heavy charged aerosol particles which are subsequently mirrored in the electron number density distribution that becomes visible to a VHF radar when small scale fluctuations are present.

  18. Exercise-induced bone gain is due to enlargement in bone size without a change in volumetric bone density: a peripheral quantitative computed tomography study of the upper arms of male tennis players.

    Science.gov (United States)

    Haapasalo, H; Kontulainen, S; Sievänen, H; Kannus, P; Järvinen, M; Vuori, I

    2000-09-01

    Bilateral bone characteristics of the humerus (proximal, shaft, and distal sites) and radius (shaft and distal sites) in 12 former Finnish national-level male tennis players (mean age 30 years) and their 12 age-, height-, and weight-matched controls were measured with peripheral quantitative computed tomography (pQCT). The pQCT variables analyzed were bone mineral content (BMC), total cross-sectional area of bone (Tot.Ar), cross-sectional area of the marrow cavity (M.Cav.Ar), cortical bone (Co.Ar) and trabecular bone (Tr.Ar), volumetric density of cortical (Co.Dn) and trabecular (Tr. Dn) bone, cortical wall thickness (Co.Wi.Th), bone strength index (BSI), and principal moments of inertia (I(min) and I(max)). In the players, significant side-to-side differences, in favor of the dominant (playing) arm, were found in BMC (ranging 14%-27%), Tot.Ar (16%-21%), Co.Ar (12%-32%), BSI (23%-37%), I(min) (33%-61%), and I(max) (27%-67%) at all measured bone sites, and in Co.Wi.Th. (5%-25%) at the humeral and radial shafts, and distal humerus. The side-to-side M.Cav.Ar difference was significant at the proximal humerus (19%) and radial shaft (29%). Concerning the players' Co.Dn and Tr.Dn, the only significant side-to-side difference was found in the Co.Dn of the distal humerus, with the playing arm showing a slightly smaller Co.Dn than the nonplaying arm (-2%). In controls, significant dominant-to-nondominant side differences were also found, but with the majority of the differences being rather small, and significantly lower than those of the players. In conclusion, despite the large side-to-side differences in BMC, the volumetric bone density (Co.Dn, Tr.Dn) was almost identical in the dominant and nondominant arms of the players and controls. Thus, the players' high playing-arm BMC was due to increases in the Tot.Ar, M.Cav.Ar, Co.Ar, and CW.Th. In other words, the playing arm's extra bone mineral, and thus increased bone strength, was mainly due to increased bone size and not

  19. Void structure and density change of vanadium-base alloys irradiated in the dynamic helium charging experiment

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Nowicki, L.; Gazda, J. [Argonne National Lab., Chicago, IL (United States)] [and others

    1995-04-01

    The objective of this work is to determine void structure, distribution, and density changes of several promising vanadium-base alloys irradiated in the Dynamic Helium Charging Experiment (DHCE). Combined effects of dynamically charged helium and neutron damage on density change, void distribution, and microstructural evolution of V-4Cr-4Ti alloy have been determined after irradiation to 18-31 dpa at 425-600{degree}C in the DHCE, and the results compared with those from a non-DHCE in which helium generation was negligible.

  20. Strain Tuning of the Charge Density Wave in Monolayer and Bilayer 1T-TaS2

    KAUST Repository

    Gan, Liyong

    2015-12-07

    By first-principles calculations, we investigate the strain effects on the charge density wave states of monolayer and bilayer 1T-TaS2. The modified stability of the charge density wave in the monolayer is understood in terms of the strain dependent electron localization, which determines the distortion amplitude. On the other hand, in the bilayer the effect of strain on the interlayer interaction is also crucial. The rich phase diagram under strain opens new venues for applications of 1T-TaS2. We interpret the experimentally observed insulating state of bulk 1T-TaS2 as inherited from the monolayer by effective interlayer decoupling.

  1. Charge density deposited in silicon by high velocity heavy ions. Densite de charges deposees par des ions lourds a haute vitesse dans le silicium

    Energy Technology Data Exchange (ETDEWEB)

    Vidiella, G.; Patin, Y. (CEA Centre d' Etudes de Bruyeres-le-Chatel, 91 (FR)); Touati, A. (Institut Curie, 75 - Paris (FR))

    1989-12-01

    For high velocity collisions, Doubly Differential Cross Sections for target ionisation (the main primary process), are well described by a recent refined theory. This allows ab initio calculation of the structure of the energy deposition in the incident ion track. Such a calculation first developed for radiobiological purpose has been applied to the case of a silicium target. Charge density profiles for various ions are presented here.

  2. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibrationa)

    Science.gov (United States)

    Kappatou, A.; Jaspers, R. J. E.; Delabie, E.; Marchuk, O.; Biel, W.; Jakobs, M. A.

    2012-10-01

    Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

  3. Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibration

    Energy Technology Data Exchange (ETDEWEB)

    Kappatou, A.; Delabie, E. [FOM Institute DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, 3430 BE Nieuwegein (Netherlands); Jaspers, R. J. E.; Jakobs, M. A. [Science and Technology of Nuclear Fusion, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Marchuk, O.; Biel, W. [Institute for Energy and Climate Research, Forschungszentrum Julich GmbH, Trilateral Euregio Cluster, 52425 Julich (Germany)

    2012-10-15

    Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

  4. Time-dependent transition density matrix for visualizing charge-transfer excitations in photoexcited organic donor-acceptor systems

    Science.gov (United States)

    Li, Yonghui; Ullrich, Carsten

    2013-03-01

    The time-dependent transition density matrix (TDM) is a useful tool to visualize and interpret the induced charges and electron-hole coherences of excitonic processes in large molecules. Combined with time-dependent density functional theory on a real-space grid (as implemented in the octopus code), the TDM is a computationally viable visualization tool for optical excitation processes in molecules. It provides real-time maps of particles and holes which gives information on excitations, in particular those that have charge-transfer character, that cannot be obtained from the density alone. Some illustration of the TDM and comparison with standard density difference plots will be shown for photoexcited organic donor-acceptor molecules. This work is supported by NSF Grant DMR-1005651

  5. Lateral phase drift of the topological charge density in stochastic optical fields

    CSIR Research Space (South Africa)

    Roux, FS

    2012-03-01

    Full Text Available The statistical distributions of optical vortices or topological charge in stochastic optical fields can be inhomogeneous in both transverse directions. Such two-dimensional inhomogeneous vortex or topological charge distributions evolve in a...

  6. The electrostatic interaction of an external charged system with a metal surface: a simplified density functional theory approach

    Science.gov (United States)

    Scivetti, Iván; Persson, Mats

    2013-09-01

    As a first step to meet the challenge to calculate the electronic structure and total energy of charged states of atoms and molecules adsorbed on ultrathin insulating films supported by a metallic substrate using density functional theory (DFT), we have developed a simplified new DFT scheme that only describes the electrostatic interaction of an external charged system with a metal surface. This purely electrostatic interaction is obtained from the assumption that the electron densities of the two fragments (charged system and metal surface) are non-overlapping and by neglecting non-local exchange-correlation effects such as the van der Waals interactions between the two fragments. In addition, the response of the metal surface to the electrostatic potential from the charged system is treated to linear order, whereas the charged system is treated fully within DFT. In particular, we consider the classical perfect conductor model for the metal response, although our formalism is not limited to this approximation. To test the computational implementation of this new scheme, we have considered the case of a Na+ cation interacting with a perfect conductor. The application of this new methodology to realistic problems involving charged systems adsorbed on insulating films supported by a metal surface are deferred to a separate following publication.

  7. First-principles studies on the charge density wave in uranium

    Science.gov (United States)

    Qiu, Ruizhi; Lu, Haiyan; Ao, Bingyun; Tang, Tao; Chen, Piheng

    2016-06-01

    The charge density wave (CDW) state of α-U (called {α1} -U) was studied through a first-principles total-energy minimization using the conjugate gradient algorithm. The optimized crystal structure of {α1} -U was found to have the space group Pbnm, which was proposed in the earlier Landau-type theory and is isostructural with the α-Np structure. In particular, the changes in the lattice parameters of Pbnm-U with respect to α-U are consistent with the experimental observations. In addition, the energetic stability of Pbnm-U with respect to α-U was confirmed by enthalpy calculations, and the value of the critical pressure in the pressure-induced quantum transition from Pbnm-U to α-U is in good agreement with the experimental result. Moreover, the phonon calculation verified the dynamical instability of α-U and the stability of Pbnm-U. Finally, the calculated electronic structures exhibit features of the CDW state.

  8. Novel charge density wave transition in crystals of R5Ir4Si10

    Indian Academy of Sciences (India)

    S Ramakrishnan

    2002-05-01

    We review the observation of novel charge density wave (CDW) transitions in ternary R5Ir4Si10 compounds. A high quality single crystal of Lu5Ir4Si10 shows the formation of a commensurate CDW along -axis below 80 K in the (ℎ, 0, ) plane that coexists with BCS type superconductivity below 3.9 K. However, in a single crystal of Er5Ir4Si10, one observes the development of a 1D-incommensurate CDW at 155 K, which then locks into a purely commensurate state below 55 K. The well-localized Er3 moments are antiferromagnetically ordered below 2.8 K which results in the coexistence of strongly coupled CDW with local moment antiferromagnetism in Er5Ir4Si10. Unlike conventional CDW systems, extremely sharp transition (width ∼ 1.5 K) in all bulk properties along with huge heat capacity anomalies in these compounds makes this CDW transition an interesting one.

  9. Mean field theory of charge-density wave state in magnetic field

    Science.gov (United States)

    Grigoriev, Pavel; Lyubshin, Dmitrij

    2005-03-01

    We develop a mean field theory of charge-density wave (CDW) state in magnetic field and study properties of this state below the transition temperature. We show that the CDW state with shifted wave vector in high magnetic field (CDWx phase) has a double harmonic modulation on the most part of the phase diagram. At perfect nesting the single harmonic CDW state with shifted wave vector exists only in a very narrow region near the triple point. We show that the transition from CDW0 to CDWx state below the critical temperature is accompanied by a jump of the CDW order parameter and of the CDW wave vector rather than by their continuous increase. This implies a first order transition between these CDW states and explains a strong hysteresis accompanying this transition. The similarities between CDW in high magnetic field and nonuniform LOFF superconducting phase are pointed out. Our investigation provides a theoretical description for recent experiments on organic metal α-(BEDT-TTF)2KHg(SCN)4 and other compounds. In particular, we explain the higher value of the kink transition field and provide the calculation of the phase diagram in the case of perfect nesting.

  10. Resonant Enhancement of Charge Density Wave Diffraction in the Rare-Earth Tri-Tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.S.; Sorini, A.P.; Yi, M.; Chuang, Y.D.; Moritz, B.; Yang, W.L.; Chu, J.-H.; Kuo, H.H.; Gonzalez, A.G.Cruz; Fisher, I.R.; Hussain, Z.; Devereau, T.P.; Shen, Z.X.

    2012-05-15

    We performed resonant soft X-ray diffraction on known charge density wave (CDW) compounds, rare earth tri-tellurides. Near the M{sub 5} (3d - 4f) absorption edge of rare earth ions, an intense diffraction peak is detected at a wavevector identical to that of CDW state hosted on Te{sub 2} planes, indicating a CDW-induced modulation on the rare earth ions. Surprisingly, the temperature dependence of the diffraction peak intensity demonstrates an exponential increase at low temperatures, vastly different than that of the CDW order parameter. Assuming 4f multiplet splitting due to the CDW states, we present a model to calculate X-ray absorption spectrum and resonant profile of the diffraction peak, agreeing well with experimental observations. Our results demonstrate a situation where the temperature dependence of resonant X-ray diffraction peak intensity is not directly related to the intrinsic behavior of the order parameter associated with the electronic order, but is dominated by the thermal occupancy of the valence states.

  11. Magnon-phonon coupling and implications for charge-density wave states and superconductivity in cuprates

    Science.gov (United States)

    Struzhkin, Viktor V.; Chen, Xiao-Jia

    2016-10-01

    The mechanism of high-temperature superconductivity of copper oxides (cuprates) remains unsolved puzzle in condensed matter physics. The cuprates represent extremely complicated system, showing fascinating variety of quantum phenomena and rich phase diagram as a function of doping. In the suggested "superconducting glue" mechanisms, phonon and spin excitations are invoked most frequently, and it appears that only spin excitations cover the energy scale required to justify very high transition temperature Tc ˜ 165 K (as in mercury-based triple layer cuprates compressed to 30 GPa). It appears that pressure is quite important variable helping to boost the Tc record by almost 30°. Pressure may be also considered as a clean tuning parameter, helping to understand the underlying balance of various energy scales and ordered states in cuprates. In this paper, a review of mostly our work on cuprates under pressure will be given, with the emphasis on the interactions between phonon and spin excitations. It appears that there is a strong coupling between superexchange interaction and stretching in-plane oxygen vibrations, which may give rise to a variety of complex phenomena, including the charge-density wave state intertwined with superconductivity and attracting a lot of interest recently.

  12. Multiple charge density wave states at the surface of TbT e3

    Science.gov (United States)

    Fu, Ling; Kraft, Aaron M.; Sharma, Bishnu; Singh, Manoj; Walmsley, Philip; Fisher, Ian R.; Boyer, Michael C.

    2016-11-01

    We studied TbT e3 using scanning tunneling microscopy (STM) in the temperature range of 298-355 K. Our measurements detect a unidirectional charge density wave (CDW) state in the surface Te layer with a wave vector consistent with that of the bulk qCDW=0.30 ±0.01 c* . However, unlike previous STM measurements, and differing from measurements probing the bulk, we detect two perpendicular orientations for the unidirectional CDW with no directional preference for the in-plane crystal axes (a or c axis) and no noticeable difference in wave vector magnitude. In addition, we find regions in which the bidirectional CDW states coexist. We propose that observation of two unidirectional CDW states indicates a decoupling of the surface Te layer from the rare-earth block layer below, and that strain variations in the Te surface layer drive the local CDW direction to the specific unidirectional or, in rare occurrences, bidirectional CDW orders observed. This indicates that similar driving mechanisms for CDW formation in the bulk, where anisotropic lattice strain energy is important, are at play at the surface. Furthermore, the wave vectors for the bidirectional order we observe differ from those theoretically predicted for checkerboard order competing with stripe order in a Fermi-surface nesting scenario, suggesting that factors beyond Fermi-surface nesting drive CDW order in TbT e3 . Finally, our temperature-dependent measurements provide evidence for localized CDW formation above the bulk transition temperature TCDW.

  13. Thickness dependent charge transfer states and dark carriers density in vacuum deposited small molecule organic photocell

    Science.gov (United States)

    Shekhar, Himanshu; Tzabari, Lior; Solomeshch, Olga; Tessler, Nir

    2016-10-01

    We have investigated the influence of the active layer thickness on the balance of the internal mechanisms affecting the efficiency of copper phthalocyanine - fullerene (C60) based vacuum deposited bulk heterojunction organic photocell. We fabricated a range of devices for which we varied the thickness of the active layer from 40 to 120 nm and assessed their performance using optical and electrical characterization techniques. As reported previously for phthalocyanine:C60, the performance of the device is highly dependent on the active layer thickness and of all the thicknesses we tried, the 40 nm thin active layer device showed the best solar cell characteristic parameters. Using the transfer matrix based optical model, which includes interference effects, we calculated the optical power absorbed in the active layers for the entire absorption band, and we found that this cannot explain the trend with thickness. Measurement of the cell quantum efficiency as a function of light intensity showed that the relative weight of the device internal processes changes when going from 40 nm to 120 nm thick active layer. Electrical modeling of the device, which takes different internal processes into account, allowed to quantify the changes in the processes affecting the generation - recombination balance. Sub gap external quantum efficiency and morphological analysis of the surface of the films agree with the model's result. We found that as the thickness grows the density of charge transfer states and of dark carriers goes up and the uniformity in the vertical direction is reduced.

  14. Analysis of Interface Charge Densities for High-k Dielectric Materials based Metal Oxide Semiconductor Devices

    Science.gov (United States)

    Maity, N. P.; Thakur, R. R.; Maity, Reshmi; Thapa, R. K.; Baishya, S.

    2016-10-01

    In this paper, the interface charge densities (Dit) are studied and analyzed for ultra thin dielectric metal oxide semiconductor (MOS) devices using different high-k dielectric materials such as Al2O3, ZrO2 and HfO2. The Dit have been calculated by a new approach using conductance method and it indicates that by reducing the thickness of the oxide, the Dit increases and similar increase is also found by replacing SiO2 with high-k. For the same oxide thickness, SiO2 has the lowest Dit and found to be the order of 1011cm-2eV-1. Linear increase in Dit has been observed as the dielectric constant of the oxide increases. The Dit is found to be in good agreement with published fabrication results at p-type doping level of 1×1017cm-3. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS.

  15. Magnetic field controlled charge density wave coupling in underdoped YBa2Cu3O6+x

    Science.gov (United States)

    Chang, J.; Blackburn, E.; Ivashko, O.; Holmes, A. T.; Christensen, N. B.; Hücker, M.; Liang, Ruixing; Bonn, D. A.; Hardy, W. N.; Rütt, U.; Zimmermann, M. V.; Forgan, E. M.; Hayden, S. M.

    2016-05-01

    The application of magnetic fields to layered cuprates suppresses their high-temperature superconducting behaviour and reveals competing ground states. In widely studied underdoped YBa2Cu3O6+x (YBCO), the microscopic nature of field-induced electronic and structural changes at low temperatures remains unclear. Here we report an X-ray study of the high-field charge density wave (CDW) in YBCO. For hole dopings ~0.123, we find that a field (B~10 T) induces additional CDW correlations along the CuO chain (b-direction) only, leading to a three-dimensional (3D) ordered state along this direction at B~15 T. The CDW signal along the a-direction is also enhanced by field, but does not develop an additional pattern of correlations. Magnetic field modifies the coupling between the CuO2 bilayers in the YBCO structure, and causes the sudden appearance of the 3D CDW order. The mirror symmetry of individual bilayers is broken by the CDW at low and high fields, allowing Fermi surface reconstruction, as recently suggested.

  16. Ideal charge-density-wave order in the high-field state of superconducting YBCO

    Science.gov (United States)

    Jang, H.; Lee, W.-S.; Nojiri, H.; Matsuzawa, S.; Yasumura, H.; Nie, L.; Maharaj, A. V.; Gerber, S.; Liu, Y.-J.; Mehta, A.; Bonn, D. A.; Liang, R.; Hardy, W. N.; Burns, C. A.; Islam, Z.; Song, S.; Hastings, J.; Devereaux, T. P.; Shen, Z.-X.; Kivelson, S. A.; Kao, C.-C.; Zhu, D.; Lee, J.-S.

    2016-12-01

    The existence of charge-density-wave (CDW) correlations in cuprate superconductors has now been established. However, the nature of the CDW ground state has remained uncertain because disorder and the presence of superconductivity typically limit the CDW correlation lengths to only a dozen unit cells or less. Here we explore the field-induced 3D CDW correlations in extremely pure detwinned crystals of YBa2Cu3O2 (YBCO) ortho-II and ortho-VIII at magnetic fields in excess of the resistive upper critical field (Hc2Hc2) where superconductivity is heavily suppressed. We observe that the 3D CDW is unidirectional and possesses a long in-plane correlation length as well as significant correlations between neighboring CuO2 planes. It is significant that we observe only a single sharply defined transition at a critical field proportional to Hc2Hc2, given that the field range used in this investigation overlaps with other high-field experiments including quantum oscillation measurements. The correlation volume is at least two to three orders of magnitude larger than that of the zero-field CDW. This is by far the largest CDW correlation volume observed in any cuprate crystal and so is presumably representative of the high-field ground state of an “ideal” disorder-free cuprate.

  17. Direct observation of many-body charge density oscillations in a two-dimensional electron gas

    Science.gov (United States)

    Sessi, Paolo; Silkin, Vyacheslav M.; Nechaev, Ilya A.; Bathon, Thomas; El-Kareh, Lydia; Chulkov, Evgueni V.; Echenique, Pedro M.; Bode, Matthias

    2015-10-01

    Quantum interference is a striking manifestation of one of the basic concepts of quantum mechanics: the particle-wave duality. A spectacular visualization of this effect is the standing wave pattern produced by elastic scattering of surface electrons around defects, which corresponds to a modulation of the electronic local density of states and can be imaged using a scanning tunnelling microscope. To date, quantum-interference measurements were mainly interpreted in terms of interfering electrons or holes of the underlying band-structure description. Here, by imaging energy-dependent standing-wave patterns at noble metal surfaces, we reveal, in addition to the conventional surface-state band, the existence of an `anomalous' energy band with a well-defined dispersion. Its origin is explained by the presence of a satellite in the structure of the many-body spectral function, which is related to the acoustic surface plasmon. Visualizing the corresponding charge oscillations provides thus direct access to many-body interactions at the atomic scale.

  18. Mapping Charge Carrier Density in Organic Thin-Film Transistors by Time-Resolved Photoluminescence Lifetime Studies

    DEFF Research Database (Denmark)

    Leißner, Till; Jensen, Per Baunegaard With; Liu, Yiming

    2017-01-01

    /organic interface or at grain boundaries. In our comprehensive experimental and analytical work we demonstrate a method to characterize the charge carrier density in organic thin-film transistors using time-resolved photoluminescence spectroscopy. We developed a numerical model that describes the electrical...

  19. Dislocations as a boundary between charge density wave and oxygen rich phases in a cuprate high temperature superconductor

    Science.gov (United States)

    Poccia, Nicola; Ricci, Alessandro; Campi, Gaetano; Bianconi, Antonio

    2017-03-01

    Multiple functional ionic and electronic orders are observed in high temperature superconducting cuprates. The charge density wave order is one of them and it is spatially localized in different regions of the material. It is also known that the oxygen interstitials introduced by chemical intercalation self-organize in different oxygen rich regions corresponding with hole rich regions in the CuO2 layers left empty by the charge density wave order domains. However, what happens in between these two orders is not known, and neither there is a method to control this spatial separation. Here we demonstrate by using scanning nano x-ray diffraction, that dislocations or grain boundaries in the material can act as boundary between charge density wave and oxygen rich phases in a optimally doped {{La}}2{{CuO}}4+y high temperature superconductor. Dislocations can be used therefore to control the anti-correlation of the charge density wave order with the oxygen interstitials in specific portion of the material.

  20. Two-dimensional aligned-field magnetofluiddynamic flow. I Steady incompressible flow with non-zero charge density

    Science.gov (United States)

    Yin, W.-L.

    1984-04-01

    It is shown that, in the case of non-zero charge density, the class of steady, plane, incompressible, aligned-fluid magnetofluiddynamic flows contains no rotational motions. Therefore, this class of flows is exhausted by the irrotational solutions of Kingston and Power.

  1. Charge and current density profiles of a degenerate magnetized free-electron gas near a hard wall

    NARCIS (Netherlands)

    M.M. Kettenis; L.G. Suttorp

    1998-01-01

    The charge and current densities of a completely degenerate free-electron gas in a uniform magnetic field are found to have a damped oscillatory spatial dependence near a wall that is parallel to the magnetic field. For large distances from the wall the behaviour of the associated profile functions

  2. SYNCHROTRON-RADIATION X-RAY-DIFFRACTION OF MODULATED STRUCTURES IN CHARGE-DENSITY-WAVE MATERIALS - APPLICATION TO NBSE3

    NARCIS (Netherlands)

    VANSMAALEN, S; DEBOER, JL; COPPENS, P

    1993-01-01

    Synchrotron radiation X-ray diffraction has been performed on niobium triselenide at 20K. The modulation parameters belonging to both Charge-Density-Waves (CDW's) have been determined. The high-temperature CDW is found to comprise of displacements on all atoms of column III, as well as on Se atoms o

  3. Molecular electronegativity in density functional theory(Ⅷ)——Charge polarization modes in a closed system

    Institute of Scientific and Technical Information of China (English)

    杨忠志; 王长生

    2000-01-01

    Based on the density functional theory and the atom-bond electronegativity equalization model (ABEEM), a method is proposed to construct the softness matrix and to obtain the electron population normal modes (PNMs) for a closed system. Using this method the information about the bond charge polarization in a molecule can be obtained easily. The test calculation shows that the PNM obtained by this method includes all the modes about the bond charge polarization explicitly. And the bond charge polarization mode characterized by the biggest eigenvalue, which is the softest one of all modes related with chemical bonds, can describe the charge polarization process in a molecule as exquisitely as the corresponding ab initio method.

  4. Effect of reduction of trap charge carrier density in organic field effect transistors by surface treatment of dielectric layer

    Energy Technology Data Exchange (ETDEWEB)

    Dagar, Janardan; Yadav, Vandana; Kumar Singh, Rajiv; Suman, C. K.; Srivastava, Ritu, E-mail: ritu@mail.nplindia.org [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, CSIR-Network of Institute for Solar Energy (NISE), Dr. K.S.Krishnan Road, New Delhi 110012 (India); Tyagi, Priyanka [Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, CSIR-Network of Institute for Solar Energy (NISE), Dr. K.S.Krishnan Road, New Delhi 110012 (India); Center for Applied Research in Electronics, Indian Institute of Technology Delhi, New Delhi 110016 (India)

    2013-12-14

    In this work, we have studied the effect of surface treatment of SiO{sub 2} dielectric layer on the reduction of the trap charge carrier density at dielectric/semiconducting interface by fabricating a metal–insulator–semiconductor (MIS) device using α, ω-dihexylcarbonylquaterthiophene as semiconducting layer. SiO{sub 2} dielectric layer has been treated with 1,1,1,3,3,3-hexamethyldisilazane (HMDS) to modify the chemical group acting as charge traps. Capacitance-voltage measurements have been performed on MIS devices fabricated on SiO{sub 2} and HMDS treated SiO{sub 2}. These data have been used for the calculation of trap charge carrier density and Debye length at the dielectric-semiconductor interface. The calculated trap charge carrier density has been found to reduce from (2.925 ± 0.049) × 10{sup 16} cm{sup −3} to (2.025 ± 0.061) × 10{sup 16} cm{sup −3} for the MIS device with HMDS treated SiO{sub 2} dielectric in comparison to that of untreated SiO{sub 2}. Next, the effect of reduction in trap charge carrier density has been studied on the performance of organic field effect transistors. The improvement in the device parameters like mobility, on/off ratio, and gate leakage current has been obtained with the effect of the surface treatment. The charge carrier mobility has been improved by a factor of 2 through this treatment. Further, the influence of the treatment was observed by atomic force microscope and Fourier transform infrared spectroscopy techniques.

  5. Origin of charge density at LaAlO3-on-SrTiO3 heterointerfacespossibility of intrinsic doping

    Energy Technology Data Exchange (ETDEWEB)

    Siemons, W.

    2010-04-29

    As discovered by Ohtomo et al., a large sheet charge density with high mobility exists at the interface between SrTiO{sub 3} and LaAlO{sub 3}. Based on transport, spectroscopic and oxygen-annealing experiments, we conclude that extrinsic defects in the form of oxygen vacancies introduced by the pulsed laser deposition process used by all researchers to date to make these samples is the source of the large carrier densities. Annealing experiments show a limiting carrier density. We also present a model that explains the high mobility based on carrier redistribution due to an increased dielectric constant.

  6. Multiple charge density wave transitions in the antiferromagnets R NiC2 (R =Gd ,Tb)

    Science.gov (United States)

    Shimomura, S.; Hayashi, C.; Hanasaki, N.; Ohnuma, K.; Kobayashi, Y.; Nakao, H.; Mizumaki, M.; Onodera, H.

    2016-04-01

    X-ray scattering and electrical resistivity measurements were performed on GdNiC2 and TbNiC2. We found a set of satellite peaks characterized by q1=(0.5 ,η ,0 ) below T1, at which the resistivity shows a sharp inflection, suggesting the charge density wave (CDW) formation. The value of η decreases with decreasing temperature below T1, and then a transition to a commensurate phase with q1 C=(0.5 ,0.5 ,0 ) takes place. The diffuse scattering observed above T1 indicates the presence of soft phonon modes associated with CDW instabilities at q1 and q2=(0.5 ,0.5 ,0.5 ) . The long-range order given by q2 is developed in addition to that given by q1 C in TbNiC2, while the short-range correlation with q2 persists even at 6 K in GdNiC2. The amplitude of the q1 C lattice modulation is anomalously reduced below an antiferromagnetic transition temperature TN in GdNiC2. In contrast, the q2 order vanishes below TN in TbNiC2. We demonstrate that R NiC2 (R = rare earth) compounds exhibit similarities with respect to their CDW phenomena, and discuss the effects of magnetic transitions on CDWs. We offer a possible displacement pattern of the modulated structure characterized by q1 C and q2 in terms of frustration.

  7. Modeling space-charge-limited currents in organic semiconductors: Extracting trap density and mobility

    KAUST Repository

    Dacuña, Javier

    2011-11-28

    We have developed and have applied a mobility edge model that takes drift and diffusion currents to characterize the space-charge-limited current in organic semiconductors into account. The numerical solution of the drift-diffusion equation allows the utilization of asymmetric contacts to describe the built-in potential within the device. The model has been applied to extract information of the distribution of traps from experimental current-voltage measurements of a rubrene single crystal from Krellner showing excellent agreement across several orders of magnitude in the current. Although the two contacts are made of the same metal, an energy offset of 580 meV between them, ascribed to differences in the deposition techniques (lamination vs evaporation) was essential to correctly interpret the shape of the current-voltage characteristics at low voltage. A band mobility of 0.13cm 2V-1s-1 for holes is estimated, which is consistent with transport along the long axis of the orthorhombic unit cell. The total density of traps deeper than 0.1 eV was 2.2×1016cm -3. The sensitivity analysis and error estimation in the obtained parameters show that it is not possible to accurately resolve the shape of the trap distribution for energies deeper than 0.3 eV or shallower than 0.1 eV above the valence-band edge. The total number of traps deeper than 0.3 eV, however, can be estimated. Contact asymmetry and the diffusion component of the current play an important role in the description of the device at low bias and are required to obtain reliable information about the distribution of deep traps. © 2011 American Physical Society.

  8. Charge density wave order in 1D mirror twin boundaries of single-layer MoSe2

    Science.gov (United States)

    Barja, Sara; Wickenburg, Sebastian; Liu, Zhen-Fei; Zhang, Yi; Ryu, Hyejin; Ugeda, Miguel M.; Hussain, Zahid; Shen, Zhi-Xun; Mo, Sung-Kwan; Wong, Ed; Salmeron, Miquel B.; Wang, Feng; Crommie, Michael F.; Ogletree, D. Frank; Neaton, Jeffrey B.; Weber-Bargioni, Alexander

    2016-08-01

    We provide direct evidence for the existence of isolated, one-dimensional charge density waves at mirror twin boundaries (MTBs) of single-layer semiconducting MoSe2. Such MTBs have been previously observed by transmission electron microscopy and have been predicted to be metallic in MoSe2 and MoS2. Our low-temperature scanning tunnelling microscopy/spectroscopy measurements revealed a substantial bandgap of 100 meV opening at the Fermi energy in the otherwise metallic one-dimensional structures. We found a periodic modulation in the density of states along the MTB, with a wavelength of approximately three lattice constants. In addition to mapping the energy-dependent density of states, we determined the atomic structure and bonding of the MTB through simultaneous high-resolution non-contact atomic force microscopy. Density functional theory calculations based on the observed structure reproduced both the gap opening and the spatially resolved density of states.

  9. Trapped charge densities in Al{sub 2}O{sub 3}-based silicon surface passivation layers

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Paul M., E-mail: Paul.Jordan@namlab.com; Simon, Daniel K.; Dirnstorfer, Ingo [NaMLab gGmbH, Nöthnitzer Str. 64, D-01187 Dresden (Germany); Mikolajick, Thomas [NaMLab gGmbH, Nöthnitzer Str. 64, D-01187 Dresden (Germany); Chair of Nanoelectronic Materials, TU Dresden, D-01062 Dresden (Germany)

    2016-06-07

    In Al{sub 2}O{sub 3}-based passivation layers, the formation of fixed charges and trap sites can be strongly influenced by small modifications in the stack layout. Fixed and trapped charge densities are characterized with capacitance voltage profiling and trap spectroscopy by charge injection and sensing, respectively. Al{sub 2}O{sub 3} layers are grown by atomic layer deposition with very thin (∼1 nm) SiO{sub 2} or HfO{sub 2} interlayers or interface layers. In SiO{sub 2}/Al{sub 2}O{sub 3} and HfO{sub 2}/Al{sub 2}O{sub 3} stacks, both fixed charges and trap sites are reduced by at least a factor of 5 compared with the value measured in pure Al{sub 2}O{sub 3}. In Al{sub 2}O{sub 3}/SiO{sub 2}/Al{sub 2}O{sub 3} or Al{sub 2}O{sub 3}/HfO{sub 2}/Al{sub 2}O{sub 3} stacks, very high total charge densities of up to 9 × 10{sup 12} cm{sup −2} are achieved. These charge densities are described as functions of electrical stress voltage, time, and the Al{sub 2}O{sub 3} layer thickness between silicon and the HfO{sub 2} or the SiO{sub 2} interlayer. Despite the strong variation of trap sites, all stacks reach very good effective carrier lifetimes of up to 8 and 20 ms on p- and n-type silicon substrates, respectively. Controlling the trap sites in Al{sub 2}O{sub 3} layers opens the possibility to engineer the field-effect passivation in the solar cells.

  10. Evaluation of intramolecular charge transfer state of 4-, -dimethylamino cinnamaldehyde using time-dependent density functional theory

    Indian Academy of Sciences (India)

    Surajit Ghosh; K V S Girish; Subhadip Ghosh

    2013-07-01

    Intramolecular charge transfer of 4-,-dimethylamino cinnamaldehyde (DMACA) in vacuum and in five different aprotic solvents has been studied by using time-dependent density functional theory (TDDFT). Polarizable continuum model (PCM) was employed to consider solvent-solute interactions. The potential energy curves were constructed at different torsional angle of ,-dimethylamino moiety with respect to the adjacent phenyl ring. A large bathochromic shift in our calculated emission and absorption energies for polar solvents is a clear reminiscent of charge transfer nature of the excited state. Finally, the reported results are in agreement with experimental findings.

  11. Form factors and transverse charge and magnetization densities in the hard-wall AdS/QCD model

    CERN Document Server

    Mondal, Chandan

    2016-01-01

    We present a study of the flavor form factors in the framework of a hard-wall AdS/QCD model and compare with the available experimental data. We obtain the flavor form factors by decomposing the Dirac and Pauli form factors for the nucleons using the charge and isospin symmetry. Further, we present a detailed study of the flavor structures of the charge and anomalous magnetization densities in the transverse plane. Both the unpolarized and the transversely polarized nucleons are considered here. We compare the AdS/QCD results with two standard phenomenological parametrizations.

  12. First experimental charge density study using a Bruker CMOS-type PHOTON 100 detector: the case of ammonium tetraoxalate dihydrate.

    Science.gov (United States)

    Jarzembska, Katarzyna N; Kamiński, Radosław; Dobrzycki, Lukasz; Cyrański, Michał K

    2014-10-01

    The aim of this study was to test the applicability of a Bruker AXS CMOS-type PHOTON 100 detector for the purpose of a fine charge density quality data collection. A complex crystal containing oxalic acid, ammonium oxalate and two water molecules was chosen as a test case. The data was collected up to a resolution of 1.31 Å(-1) with high completeness (89.1%; Rmrg = 0.0274). The multipolar refinement and subsequent quantum theory of atoms in molecules (QTAIM) analysis resulted in a comprehensive description of the charge density distribution in the crystal studied. The residual density maps are flat and almost featureless. It was possible to derive reliable information on intermolecular interactions to model the anharmonic motion of a water molecule, and also to observe the fine details of the charge density distribution, such as polarization on O and H atoms involved in the strongest hydrogen bonds. When compared with our previous statistical study on oxalic acid data collected with the aid of CCD cameras, the complementary metal-oxide semiconductor (CMOS) detector can certainly be classified as a promising alternative in advanced X-ray diffraction studies.

  13. Full charge-density scheme with a kinetic-energy correction: Application to ground-state properties of the 4d metals

    DEFF Research Database (Denmark)

    Vitos, Levente; Kollár, J.; Skriver, Hans Lomholt

    1997-01-01

    We present a full charge-density technique to evaluate total energies from the output of self-consistent linear muffin-tin orbitals (LMTO) calculations in the atomic-sphere approximation (ASA). The Coulomb energy is calculated exactly from the complete, nonspherically symmetric charge density def...

  14. Development and Application of a Wireless Sensor for Space Charge Density Measurement in an Ultra-High-Voltage, Direct-Current Environment.

    Science.gov (United States)

    Xin, Encheng; Ju, Yong; Yuan, Haiwen

    2016-10-20

    A space charge density wireless measurement system based on the idea of distributed measurement is proposed for collecting and monitoring the space charge density in an ultra-high-voltage direct-current (UHVDC) environment. The proposed system architecture is composed of a number of wireless nodes connected with space charge density sensors and a base station. The space charge density sensor based on atmospheric ion counter method is elaborated and developed, and the ARM microprocessor and Zigbee radio frequency module are applied. The wireless network communication quality and the relationship between energy consumption and transmission distance in the complicated electromagnetic environment is tested. Based on the experimental results, the proposed measurement system demonstrates that it can adapt to the complex electromagnetic environment under the UHVDC transmission lines and can accurately measure the space charge density.

  15. Stripe and Short Range Order in the Charge Density Wave of 1 T -CuxTiSe2

    Science.gov (United States)

    Novello, A. M.; Spera, M.; Scarfato, A.; Ubaldini, A.; Giannini, E.; Bowler, D. R.; Renner, Ch.

    2017-01-01

    We study the impact of Cu intercalation on the charge density wave (CDW) in 1 T -CuxTiSe2 by scanning tunneling microscopy and spectroscopy. Cu atoms, identified through density functional theory modeling, are found to intercalate randomly on the octahedral site in the van der Waals gap and to dope delocalized electrons near the Fermi level. While the CDW modulation period does not depend on Cu content, we observe the formation of charge stripe domains at low Cu content (x domains at higher Cu content. The latter shrink with increasing Cu concentration and tend to be phase shifted. These findings invalidate a proposed excitonic pairing as the primary CDW formation mechanism in this material.

  16. Charge density analysis of two proton transfer complexes: Understanding hydrogen bonding and determination of in-crystal dipole moments

    Indian Academy of Sciences (India)

    Reji Thomas; Shrinwantu Pal; Ayan Datta; Mariusz K Marchewka; Henryk Ratajczak; Swapan K Pati; G U Kulkarni

    2008-11-01

    An experimental charge density study has been carried out on proton-transfer complexes exhibiting nonlinear optical (NLO) properties-melaminium tartrate monohydrate and L-asparaginium picrate employing high-resolution X-ray diffraction at 100 K. Both the complexes crystallize in non-centric space group P21 and the structures exhibit interesting patterns of N-H…O and O-H…O hydrogen bonding. Experimental determination of the dipole moment () for the asymmetric unit reveals that for both the crystals, there is a large cooperative enhancement in the crystalline arising essentially due to hydrogen bond mediated charge transfer between the melaminium ion and the L-tartrate in one case, between the Lasparaginium ion and the picrate in the other complex. We have additionally performed theoretical calculations at the density functional theory (DFT) level to understand the origin of enhancement of the dipole moments in the two systems.

  17. Direct observation of competition between superconductivity and charge density wave order in YBa2Cu3O6.67

    DEFF Research Database (Denmark)

    Chang, J.; Blackburn, E.; Holmes, A. T.

    2012-01-01

    Superconductivity often emerges in the proximity of, or in competition with, symmetry-breaking ground states such as antiferromagnetism or charge density waves (CDW). A number of materials in the cuprate family, which includes the high transition-temperature (high-Tc) superconductors, show spin...... and charge density wave order. Thus a fundamental question is to what extent do these ordered states exist for compositions close to optimal for superconductivity. Here we use high-energy X-ray diffraction to show that a CDW develops at zero field in the normal state of superconducting YBa2Cu3O6.67 (Tc= 67 K......). This sample has a hole doping of 0.12 per copper and a well-ordered oxygen chain superstructure. Below Tc, the application of a magnetic field suppresses superconductivity and enhances the CDW. Hence, the CDW and superconductivity in this typical high-Tc material are competing orders with similar energy...

  18. Spin polarization driven by a charge-density wave in monolayer 1T−TaS2

    KAUST Repository

    Zhang, Qingyun

    2014-08-06

    Using first-principles calculations, we investigate the electronic and vibrational properties of monolayer T-phase TaS2. We demonstrate that a charge-density wave is energetically favorable at low temperature, similar to bulk 1T-TaS2. Electron-phonon coupling is found to be essential for the lattice reconstruction. The charge-density wave results in a strong localization of the electronic states near the Fermi level and consequently in spin polarization, transforming the material into a magnetic semiconductor with enhanced electronic correlations. The combination of inherent spin polarization with a semiconducting nature distinguishes the monolayer fundamentally from the bulk compound as well as from other two-dimensional transition metal dichalcogenides. Monolayer T-phase TaS2 therefore has the potential to enable two-dimensional spintronics. © 2014 American Physical Society.

  19. Charge-density-wave formation in Ta2NiSe7 studied by scanning tunneling microscopy

    Science.gov (United States)

    Dai, Zhenxi; Slough, C. G.; McNairy, W. W.; Coleman, R. V.

    1992-09-01

    Scanning tunneling microscope images of Ta2NiSe7 taken at 77 and 4.2 K show a complex electronic rearrangment occurring below the charge-density-wave (CDW) onset temperature of 52.5 K. A large energy gap of 41.0+/-3.0 meV is observed and a CDW amplitude modulation of wavelength ~2b0 is detected. The electronic transfer between chains appears to drive the CDW formation.

  20. Giant Nernst effect in the incommensurate charge density wave state of P4W12O44

    Science.gov (United States)

    Kolincio, Kamil K.; Daou, Ramzy; Pérez, Olivier; Guérin, Laurent; Fertey, Pierre; Pautrat, Alain

    2016-12-01

    We report the study of Nernst effect in quasi-low-dimensional tungsten bronze P4W12O44 showing a sequence of Peierls instabilities. We demonstrate that both condensation of the electronic carriers in the charge density wave state and the existence of high-mobility electrons and holes originating from the small pockets remaining in the incompletely nested Fermi surface give rise to a Nernst effect of a magnitude similar to that observed in heavy fermion compounds.

  1. Unconventional charge density wave in the organic conductor alpha-(BEDT-TTF)_2KHg(SCN)_4

    OpenAIRE

    Maki, Kazumi; Dóra, Balázs; Kartsovnik, Mark; Virosztek, Attila; Korin-Hamzic, Bojana; Basletic, Mario

    2002-01-01

    The low temperature phase (LTP) of alpha-(BEDT-TTF)_2KHg(SCN)_4 salt is known for its surprising angular dependent magnetoresistance (ADMR), which has been studied intensively in the last decade. However, the nature of the LTP has not been understood until now. Here we analyse theoretically ADMR in unconventional (or nodal) charge density wave (UCDW). In magnetic field the quasiparticle spectrum in UCDW is quantized, which gives rise to spectacular ADMR. The present model accounts for many st...

  2. De Haas-van Alphen oscillations in the charge-density wave compound lanthanum tritelluride (LaTe3)

    Energy Technology Data Exchange (ETDEWEB)

    Ru, N.; /Stanford U., Geballe Lab.; Borzi, R.A.; Rost, A.; Mackenzie, A.P.; /St. Andrews U., Phys. Astron.; Laverock, J.; Dugdale, S.B.; /Bristol U.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2009-12-14

    De Haas-van Alphen oscillations were measured in lanthanum tritelluride (LaTe{sub 3}) to probe the partially gapped Fermi surface resulting from charge density wave (CDW) formation. Three distinct frequencies were observed, one of which can be correlated with a FS sheet that is unaltered by CDW formation. The other two frequencies arise from FS sheets that have been reconstructed in the CDW state.

  3. Molecular electronegativity in density functional theory (II) --Direct calculation of group electronegativity and the atomic charges in a group

    Institute of Scientific and Technical Information of China (English)

    杨忠志; 沈尔忠

    1996-01-01

    On the basis of a more precise expression of the atomic effective electronegativity deduced from the density functional theory and electronegativity equalization principle, a new scheme for calculating the group electronegativity and the atomic charges in a group is proposed and programed, and various parameters of electronegativity and hardness are given for some common atoms. Through calculation, analysis and comparison of more than one hundred groups, it is shown that the results from this scheme are reasonable and may be extended.

  4. A simplified density functional theory method for charged adsorbates on an ultrathin, insulating film supported by a metal substrate

    OpenAIRE

    Scivetti, Ivan; Persson, Mats

    2013-01-01

    A simplified density functional theory (DFT) method for charged adsorbates on an ultrathin, insulating film supported by a metal substrate is developed and presented. This new method is based on a previous DFT development that uses a perfect conductor (PC) model to approximate the electrostatic response of the metal substrate, while the film and the adsorbate are both treated fully within DFT [I. Scivetti and M. Persson, Journal of Physics: Condensed Matter 25, 355006 (2013)]. The missing int...

  5. Spatial distribution of electrons near the Fermi level in the metallic LaB6 through accurate X-ray charge density study

    Science.gov (United States)

    Kasai, Hidetaka; Nishibori, Eiji

    2017-01-01

    Charge densities of iso-structural metal hexaborides, a transparent metal LaB6 and a semiconductor BaB6, have been determined using the d > 0.22 Å ultra-high resolution synchrotron radiation X-ray diffraction data by a multipole refinement and a maximum entropy method (MEM). The quality of the experimental charge densities was evaluated by comparison with theoretical charge densities. The strong inter-octahedral and relatively weak intra-octahedral boron-boron bonds were observed in the charge densities. A difference of valence charge densities between LaB6 and BaB6 was calculated to reveal a small difference between isostructural metal and semiconductor. The weak electron lobes distributed around the inter B6 octahedral bond were observed in the difference density. We found the electron lobes are the conductive π-electrons in LaB6 from the comparison with the theoretical valence charge density. We successfully observed a spatial distribution of electrons near the Fermi level from the X-ray charge density study of the series of iso-structural solids. PMID:28120900

  6. Charge density study on cyclosporine A. Methodical evaluations for the application of area detectors for charge density studies; Elektronendichtestudie an Cyclosporin A. Methodische Untersuchungen zum Einsatz von Flaechendetektoren fuer Elektronendichtestudien

    Energy Technology Data Exchange (ETDEWEB)

    Johnas, S.K.J.

    2008-02-15

    The aim of this work has been the electron density study on the relatively large and pharmaceutical interesting molecule cyclosporine A (C{sub 62}H{sub 111}N{sub 11}O{sub 12}) in order to investigate the currently available experimental possibilities and analysis methods for larger organic structures. The applied experimental measurement method has been evaluated thoroughly and has accented the need for the development of an oblique incidence correction for intensity data from high resolution crystal structure analysis datasets (beyond D{sub min}=0.5 A) collected using area detectors. This issue is due to the application of hard X-rays for X-ray diffraction experiments, for crystals of organic substances about 20 keV and higher, since it has the advantage of minimising systematic errors like absorption and extinction. Furthermore, only area detectors enable the collection of intensity data necessary within a practical time frame, especially for crystals with large unit cells. For the electron density study on cyclosporine A, X-ray diffraction experiments with single crystals have been carried out at low temperatures at Swiss Light Source (SLS). The developed oblique incidence correction has been applied to these datasets. Subsequently, the structure has been refined using the multipole model by Hansen and Coppens, which takes into account the deformation of the atomic electron density due to chemical bonding effects. The applied programs needed to be adjusted because of the large size of the molecule. Thus, the electron density has been studied in detail. The resulting physical and chemical characteristics have been quantified, such as the topology of the electron density, the electrostatic potential and the atomic volumes and charges. The reflection intensities, which are obtained by the developed intensity correction, are appropriate for a detailed charge density determination even for relatively large structures. (orig.)

  7. Mapping Optimal Charge Density and Length of ROMP-Based PTDMs for siRNA Internalization.

    Science.gov (United States)

    Caffrey, Leah M; deRonde, Brittany M; Minter, Lisa M; Tew, Gregory N

    2016-10-10

    A fundamental understanding of how polymer structure impacts internalization and delivery of biologically relevant cargoes, particularly small interfering ribonucleic acid (siRNA), is of critical importance to the successful design of improved delivery reagents. Herein we report the use of ring-opening metathesis polymerization (ROMP) methods to synthesize two series of guanidinium-rich protein transduction domain mimics (PTDMs): one based on an imide scaffold that contains one guanidinium moiety per repeat unit, and another based on a diester scaffold that contains two guanidinium moieties per repeat unit. By varying both the degree of polymerization and, in effect, the relative number of cationic charges in each PTDM, the performances of the two ROMP backbones for siRNA internalization were evaluated and compared. Internalization of fluorescently labeled siRNA into Jurkat T cells demonstrated that fluorescein isothiocyanate (FITC)-siRNA internalization had a charge content dependence, with PTDMs containing approximately 40 to 60 cationic charges facilitating the most internalization. Despite this charge content dependence, the imide scaffold yielded much lower viabilities in Jurkat T cells than the corresponding diester PTDMs with similar numbers of cationic charges, suggesting that the diester scaffold is preferred for siRNA internalization and delivery applications. These developments will not only improve our understanding of the structural factors necessary for optimal siRNA internalization, but will also guide the future development of optimized PTDMs for siRNA internalization and delivery.

  8. Synthesis of crosslinked poly(styrene--divinylbenzene--sulfopropyl methacrylate) nanoparticles by emulsion polymerization: Tuning the particle size and surface charge density

    Indian Academy of Sciences (India)

    Dhamodaran Arunbabu; Mousumi Hazarika; Somsankar Naik; Tushar Jana

    2009-12-01

    We have synthesized highly charged, crosslinked poly (styrene--divinylbenzene--sulfopropyl methacrylate) copolymer colloidal particles using emulsion polymerization. The effects of concentration of the emulsifier and the initiator on the particle size and the charge density of the colloidal particles are studied. Colloidal particle size is highly dependent upon the concentration of the emulsifier and the initiator. The colloidal particle diameter decreases with increasing concentration of the emulsifier and increases with increasing concentration of the initiator in the polymerization mixture. Number of particles, surface charge density and charges per particle are also functions of both the emulsifier and the initiator concentration. The surface charge density and the number of charges per sphere increase with increasing particle diameter. These copolymer colloid particles self assemble readily and diffract visible light. Polymer hydrogel imbibed with these colloids shows the light diffraction.

  9. Charge compensation and electrostatic transferability in three entropy-stabilized oxides: Results from density functional theory calculations

    Science.gov (United States)

    Rak, Zs.; Rost, C. M.; Lim, M.; Sarker, P.; Toher, C.; Curtarolo, S.; Maria, J.-P.; Brenner, D. W.

    2016-09-01

    Density functional theory calculations were carried out for three entropic rocksalt oxides, (Mg0.1Co0.1Ni0.1Cu0.1Zn0.1)O0.5, termed J14, and J14 + Li and J14 + Sc, to understand the role of charge neutrality and electronic states on their properties, and to probe whether simple expressions may exist that predict stability. The calculations predict that the average lattice constants of the ternary structures provide good approximations to that of the random structures. For J14, Bader charges are transferable between the binary, ternary, and random structures. For J14 + Sc and J14 + Li, average Bader charges in the entropic structures can be estimated from the ternary compositions. Addition of Sc to J14 reduces the majority of Cu, which show large displacements from ideal lattice sites, along with reduction of a few Co and Ni cations. Addition of Li to J14 reduces the lattice constant, consistent with experiment, and oxidizes some of Co as well as some of Ni and Cu. The Bader charges and spin-resolved density of states (DOS) for Co+3 in J14 + Li are very different from Co+2, while for Cu and Ni the Bader charges form continuous distributions and the two DOS are similar for the two oxidation states. Experimental detection of different oxidation states may therefore be challenging for Cu and Ni compared to Co. Based on these results, empirical stability parameters for these entropic oxides may be more complicated than those for non-oxide entropic solids.

  10. Charge compensation and electrostatic transferability in three entropy-stabilized oxides: Results from density functional theory calculations

    Energy Technology Data Exchange (ETDEWEB)

    Rak, Zs.; Rost, C. M.; Lim, M.; Maria, J.-P.; Brenner, D. W. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States); Sarker, P.; Toher, C.; Curtarolo, S. [Department of Mechanical Engineering and Materials Science and Center for Materials Genomics, Duke University, Durham, North Carolina 27708 (United States)

    2016-09-07

    Density functional theory calculations were carried out for three entropic rocksalt oxides, (Mg{sub 0.1}Co{sub 0.1}Ni{sub 0.1}Cu{sub 0.1}Zn{sub 0.1})O{sub 0.5}, termed J14, and J14 + Li and J14 + Sc, to understand the role of charge neutrality and electronic states on their properties, and to probe whether simple expressions may exist that predict stability. The calculations predict that the average lattice constants of the ternary structures provide good approximations to that of the random structures. For J14, Bader charges are transferable between the binary, ternary, and random structures. For J14 + Sc and J14 + Li, average Bader charges in the entropic structures can be estimated from the ternary compositions. Addition of Sc to J14 reduces the majority of Cu, which show large displacements from ideal lattice sites, along with reduction of a few Co and Ni cations. Addition of Li to J14 reduces the lattice constant, consistent with experiment, and oxidizes some of Co as well as some of Ni and Cu. The Bader charges and spin-resolved density of states (DOS) for Co{sup +3} in J14 + Li are very different from Co{sup +2}, while for Cu and Ni the Bader charges form continuous distributions and the two DOS are similar for the two oxidation states. Experimental detection of different oxidation states may therefore be challenging for Cu and Ni compared to Co. Based on these results, empirical stability parameters for these entropic oxides may be more complicated than those for non-oxide entropic solids.

  11. X-ray derived experimental charge density distribution in GaF3 and VF3 solid systems

    Science.gov (United States)

    Sujatha, K.; Israel, S.; Anzline, C.; Niranjana Devi, R.; Sheeba, R. A. J. R.

    2016-09-01

    The electronic structure and bonding features of metal and transition metal fluorides in low oxidation states, GaF3 and VF3, have been studied from precise single crystal X-ray diffraction data using multipole and maximum entropy methods. The topology of the charge density is analyzed and the (3,-1) bond critical points are determined. Existences of ionic nature of bonding in low valent fluorine compounds are clearly evident. The spherical core of metal atom and aspherical or twisted core of transition metal atom reveal the fact that GaF3 is much more rigid than VF3. Aspherical cores of the polarized ligand atoms are also visible in the two-dimensional density distribution pictures. The true valence charge density surfaces with encapsulating the atomic basins maps are elucidated. An elongated saddle with mid-bond density of 0.6191 e/Å3, observed in the compound VF3, shows that its lattice is less rigid and has more ionic character than GaF3.

  12. Densities and volumetric properties of binary mixtures of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate with benzaldehyde at T = (298.15 to 313.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Gao Haiyan; Qi Feng [School of Chemical and Material Engineering, Jiangnan University, Road of Lihu, Wuxi, Jiangsu 214122 (China); Wang Haijun [School of Chemical and Material Engineering, Jiangnan University, Road of Lihu, Wuxi, Jiangsu 214122 (China)], E-mail: wanghj329@hotmail.com

    2009-07-15

    The densities of the binary mixtures formed by 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF{sub 4}] with aromatic compound (benzaldehyde) have been determined over the full range of compositions at the temperature range from (298.15 to 313.15) K and at atmospheric pressure using a vibrating-tube densimeter (DMA4500). Excess molar volumes (V{sub m}{sup E}) have been obtained from these experimental results, and been fitted by the fourth-order Redlich-Kister equation. In addition, partial molar volumes, apparent molar volumes, and partial molar volumes at infinite dilution have been calculated for each component. Our results show V{sub m}{sup E} decreases slightly when temperature increases in the systems studied. The results have been interpreted in terms of ion-dipole interactions and structural factors of the ionic liquid and these organic molecular liquids.

  13. Exploring the rare S-H...S hydrogen bond using charge density analysis in isomers of mercaptobenzoic acid.

    Science.gov (United States)

    Pavan, Mysore S; Sarkar, Sounak; Row, Tayur N Guru

    2017-08-01

    Experimental and theoretical charge density analyses on isomers of mercaptobenzoic acid have been carried out to quantify the hydrogen bonding of the hitherto less explored thiols, to assess the strength of the interactions using the topological features of the electron density. The electron density study offers interesting insights into the nature of the S-H...S interaction. The interaction energy is comparable with that of a weak hydrogen bond. The strength and directionality of the S-H...S hydrogen bond is demonstrated to be mainly due to the conformation locking potential of the intramolecular S...O chalcogen bond in 2-mercaptobenzoic acid and is stronger than in 3-mercaptobenzoic acid, which lacks the intramolecular S...O bond. The para-substituted mercaptobenzoic acid depicts a type I S...S interaction.

  14. Relativistic mean field theory with density dependent coupling constants for nuclear matter and finite nuclei with large charge asymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Typel, S.; Wolter, H.H. [Sektion Physik, Univ. Muenchen, Garching (Germany)

    1998-06-01

    Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for {sigma}-, {omega}- and {rho}-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)

  15. A simplified density functional theory method for investigating charged adsorbates on an ultrathin, insulating film supported by a metal substrate.

    Science.gov (United States)

    Scivetti, Ivan; Persson, Mats

    2014-04-02

    A simplified density functional theory (DFT) method for investigating charged adsorbates on an ultrathin, insulating film supported by a metal substrate is developed and presented. This new method is based on a previous DFT development that uses a perfect conductor (PC) model to approximate the electrostatic response of the metal substrate, while the film and the adsorbate are both treated fully within DFT (Scivetti and Persson 2013 J. Phys.: Condens. Matter 25 355006). The missing interactions between the metal substrate and the insulating film in the PC approximation are modelled by a simple force field (FF). The parameters of the PC model and the force field are obtained from DFT calculations of the film and the substrate, here shown explicitly for a NaCl bilayer supported by a Cu(100) surface. In order to obtain some of these parameters and the polarizability of the force field, we have to include an external, uniformly charged plane in the DFT calculations, which has required the development of a periodic DFT formalism to include such a charged plane in the presence of a metal substrate. This extension and implementation should be of more general interest and applicable to other challenging problems, for instance, in electrochemistry. As illustrated for the gold atom on the NaCl bilayer supported by a Cu(100) surface, our new DFT-PC-FF method allows us to handle different charge states of adsorbates in a controlled and accurate manner with a considerable reduction of the computational time. In addition, it is now possible to calculate vertical transition and reorganization energies for the charging and discharging of adsorbates that cannot be obtained by current DFT methodologies that include the metal substrate. We find that the computed vertical transition energy for charging of the gold adatom is in good agreement with experiments.

  16. Charged particle density distributions in Au + Au collisions at relativistic heavy-ion collider energies

    Indian Academy of Sciences (India)

    Fauad Rami

    2003-05-01

    Charged particle pseudorapidity distributions have been measured in Au + Au collisions using the BRAHMS detector at RHIC. The results are presented as a function of the collision centrality and the center of mass energy. They are compared to the predictions of different parton scattering models and the important role of hard scattering processes at RHIC energies is discussed.

  17. Microtubule Protofilament Number Is Modulated in a Step-Wise Fashion By the Charge of Density of An Enveloping Layer

    Energy Technology Data Exchange (ETDEWEB)

    Raviv, U.; Nguyen, T.; Ghafouri, R.; Needleman, D.J.; Li, Y.; Miller, H.P.; Wilson, L.; Bruinsma, R.F.; Safinya, C.R.; /UC, Santa Barbara /UCLA

    2007-07-12

    Microtubules are able to adjust their protofilament (PF) number and, as a consequence, their dynamics and function, to the assembly conditions and presence of cofactors. However, the principle behind such variations is poorly understood. Using synchrotron x-ray scattering and transmission electron microscopy, we studied how charged membranes, which under certain conditions can envelop preassembled MTs, regulate the PF number of those MTs. We show that the mean PF number, , is modulated primarily by the charge density of the membranes. decreases in a stepwise fashion with increasing membrane charge density. does not depend on the membrane-protein stoichiometry or the solution ionic strength. We studied the effect of taxol and found that increases logarithmically with taxol/tubulin stoichiometry. We present a theoretical model, which by balancing the electrostatic and elastic interactions in the system accounts for the trends in our findings and reveals an effective MT bending stiffness of order 10-100 k{sub B}T/nm, associated with the observed changes in PF number.

  18. Ionic Wind Phenomenon and Charge Carrier Mobility in Very High Density Argon Corona Discharge Plasma

    Science.gov (United States)

    Nur, M.; Bonifaci, N.; Denat, A.

    2014-04-01

    Wind ions phenomenon has been observed in the high density argon corona discharge plasma. Corona discharge plasma was produced by point to plane electrodes and high voltage DC. Light emission from the recombination process was observed visually. The light emission proper follow the electric field lines that occur between point and plane electrodes. By using saturation current, the mobilities of non-thermal electrons and ions have been obtained in argon gas and liquid with variation of density from 2,5 1021 to 2 1022 cm-3. In the case of ions, we found that the behaviour of the apparent mobility inversely proportional to the density or follow the Langevin variation law. For non-thermal electron, mobility decreases and approximately follows a variation of Langevin type until the density <= 0,25 the critical density of argon.

  19. A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density

    Science.gov (United States)

    Hiemstra, Tjisse; Van Riemsdijk, Willem H.

    2009-08-01

    A multisite surface complexation (MUSIC) model for ferrihydrite (Fh) has been developed. The surface structure and composition of Fh nanoparticles are described in relation to ion binding and surface charge development. The site densities of the various reactive surface groups, the molar mass, the mass density, the specific surface area, and the particle size are quantified. As derived theoretically, molecular mass and mass density of nanoparticles will depend on the types of surface groups and the corresponding site densities and will vary with particle size and surface area because of a relatively large contribution of the surface groups in comparison to the mineral core of nanoparticles. The nano-sized (˜2.6 nm) particles of freshly prepared 2-line Fh as a whole have an increased molar mass of M ˜ 101 ± 2 g/mol Fe, a reduced mass density of ˜3.5 ± 0.1 g/cm 3, both relatively to the mineral core. The specific surface area is ˜650 m 2/g. Six-line Fh (5-6 nm) has a molar mass of M ˜ 94 ± 2 g/mol, a mass density of ˜3.9 ± 0.1 g/cm 3, and a surface area of ˜280 ± 30 m 2/g. Data analysis shows that the mineral core of Fh has an average chemical composition very close to FeOOH with M ˜ 89 g/mol. The mineral core has a mass density around ˜4.15 ± 0.1 g/cm 3, which is between that of feroxyhyte, goethite, and lepidocrocite. These results can be used to constrain structural models for Fh. Singly-coordinated surface groups dominate the surface of ferrihydrite (˜6.0 ± 0.5 nm -2). These groups can be present in two structural configurations. In pairs, the groups either form the edge of a single Fe-octahedron (˜2.5 nm -2) or are present at a single corner (˜3.5 nm -2) of two adjacent Fe octahedra. These configurations can form bidentate surface complexes by edge- and double-corner sharing, respectively, and may therefore respond differently to the binding of ions such as uranyl, carbonate, arsenite, phosphate, and others. The relatively low PZC of

  20. Manipulating charge density waves in 1 T -TaS2 by charge-carrier doping: A first-principles investigation

    Science.gov (United States)

    Shao, D. F.; Xiao, R. C.; Lu, W. J.; Lv, H. Y.; Li, J. Y.; Zhu, X. B.; Sun, Y. P.

    2016-09-01

    The transition-metal dichalcogenide 1 T -TaS2 exhibits a rich set of charge-density-wave (CDW) orders. Recent investigations suggested that using light or an electric field can manipulate the commensurate CDW (CCDW) ground state. Such manipulations are considered to be determined by charge-carrier doping. Here we use first-principles calculations to simulate the carrier-doping effect on the CCDW in 1 T -TaS2 . We investigate the charge-doping effects on the electronic structures and phonon instabilities of the 1 T structure, and we analyze the doping-induced energy and distortion ratio variations in the CCDW structure. We found that both in bulk and monolayer 1 T -TaS2 , the CCDW is stable upon electron doping, while hole doping can significantly suppress the CCDW, implying different mechanisms of such reported manipulations. Light or positive perpendicular electric-field-induced hole doping increases the energy of the CCDW, so that the system transforms to a nearly commensurate CDW or a similar metastable state. On the other hand, even though the CCDW distortion is more stable upon in-plane electric-field-induced electron injection, some accompanied effects can drive the system to cross over the energy barrier from the CCDW to a nearly commensurate CDW or a similar metastable state. We also estimate that hole doping can introduce potential superconductivity with a Tc of 6-7 K. Controllable switching of different states such as a CCDW/Mott insulating state, a metallic state, and even a superconducting state can be realized in 1 T -TaS2 . As a result, this material may have very promising applications in future electronic devices.

  1. Effect of Loading Densities in Closed Vessel Tests on the Burning Rate of a Propelling Charge

    Directory of Open Access Journals (Sweden)

    Pragati Mehta

    2015-04-01

    Full Text Available Closed vessel firing of gun propellant at different loading densities is conducted for evaluation of its ballistic parameters. Although in actual gun applications, loading densities are higher, but for closed vessel evaluation standard loading density is taken as 0.2 g/cc for interior ballistic calculations of guns. Closed vessel evaluation of standard triple-base propellant in hepta-tubular configuration with loading density varying in the range of 0.2 g/cc to 0.3 g/cc is conducted for the evaluation of salient ballistic parameters. It is observed that maximum pressure increases with increase in loading density of propellants. As loading density increases, rate of rise of pressure also increases. Accordingly, a rise in burning rate is also observed. However, the burning rate index (α and coefficient (β of the power law of burning (r = βPα is found independent of loading density. The average values of these burning rate parameters are calculated as (α = 0.78 and (β = 0.45 for the studied propellant.Defence Science Journal, Vol. 65, No. 2, March 2015, pp.126-130, DOI:http://dx.doi.org/10.14429/dsj.65.8158

  2. Fission fragment charge and mass distributions in 239Pu(n,f) in the adiabatic nuclear energy density functional theory

    CERN Document Server

    Regnier, D; Schunck, N; Verriere, M

    2016-01-01

    Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r-process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data is available is an incentive to develop a fully microscopic approach to fission dynamics. In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of 239Pu using a microscopic method based on nuclear energy density functional (EDF) method, where large amplitude collective motion is treated adiabatically using the time dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line. We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in tw...

  3. Parametric study of a high current–density EBIS Charge Breeder regarding Two Stream plasma Instability (TSI)

    Energy Technology Data Exchange (ETDEWEB)

    Shornikov, Andrey, E-mail: andrey.shornikov@cern.ch [CERN, AB Department, CH-1211 Geneva 23 (Switzerland); Mertzig, Robert; Breitenfeldt, Martin; Lombardi, Alessandra; Wenander, Fredrik [CERN, AB Department, CH-1211 Geneva 23 (Switzerland); Pikin, Alexander [BNL, Upton, NY (United States)

    2016-06-01

    In this paper we report on our results from the design study of an advanced Electron Beam Ion Source (EBIS) based Charge Breeder (ECB). The ECB should fulfill the requirements of the HIE-ISOLDE upgrade, and if possible be adapted for ion injection into TSR@ISOLDE, as well as serve as an early prototype of a future EURISOL ECB. Fulfilling the HIE-ISOLDE/TSR@ISOLDE specifications requires simultaneous increase in electron beam energy, current and current density in order to provide the requested beams with proper charge state, high intensity and with a specified pulse repetition rate. We have carried out a study on the technical requirements of the ECB. The obtained parameters were optimized to comply with technical limitations arising from the electron beam technology and plasma physics in an ECB.

  4. Magnetic field-induced charge-density-wave transitions: The role of the orbital and Pauli effects

    Science.gov (United States)

    Kartsovnik, M. V.; Andres, D.; Biberacher, W.; Müller, H.

    2009-03-01

    Due to a low transition temperature and, correspondingly, a small energy gap, the charge-density-wave (CDW) state of the layered organic metal α-(BEDT-TTF)2KHg(SCN)4 is very sensitive to pressure and magnetic field. The latter couples to the CDW via two competing mechanisms: Pauli paramagnetism and orbital motion of charge carriers in a magnetic field. We study the interplay between the Pauli and orbital effects under a pressure of 2.8 kbar, in the region of the field-induced CDW (FICDW) instability. We find that, in agreement with theoretical predictions, the FICDW state is enhanced when the Zeeman splitting becomes commensurate with the orbital quantization.

  5. Magnetic field-induced charge-density-wave transitions: The role of the orbital and Pauli effects

    Energy Technology Data Exchange (ETDEWEB)

    Kartsovnik, M.V. [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany)], E-mail: mark.kartsovnik@wmi.badw.de; Andres, D.; Biberacher, W. [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Mueller, H. [European Synchrotron Radiation Facility, F-38043 Grenoble (France)

    2009-03-01

    Due to a low transition temperature and, correspondingly, a small energy gap, the charge-density-wave (CDW) state of the layered organic metal {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} is very sensitive to pressure and magnetic field. The latter couples to the CDW via two competing mechanisms: Pauli paramagnetism and orbital motion of charge carriers in a magnetic field. We study the interplay between the Pauli and orbital effects under a pressure of 2.8 kbar, in the region of the field-induced CDW (FICDW) instability. We find that, in agreement with theoretical predictions, the FICDW state is enhanced when the Zeeman splitting becomes commensurate with the orbital quantization.

  6. Anisotropic symmetry breaking in two-dimensional charge density waves of ErTe3 investigated by femtosecond electron crystallography

    Science.gov (United States)

    Zhou, Faran; Golubev, Timofey; Hwang, Bin; Ruan, Chong-Yu; Duxbury, Phil; Malliakas, Christos; Kanatzidis, Mercouri

    2015-03-01

    Electron-phonon interactions can give rise to various charge-ordered states, especially at low dimensions, where Fermi surface is more prone to form nesting. Rare earth tritellurides compound ErTe3 develops charge density waves (CDW) along two perpendicular directions at different temperatures. By directly probing the order parameters of the two CDWs using femtosecond electron crystallography under different temperatures and driving photonic energy, we investigated the emergences of competing CDW orders in a dynamical phase diagram. The anisotropic symmetry breaking and the role of electron-phonon coupling, and photo-doping effect are discussed in reference to other CDW systems. Our work is supported by Department of Energy under Grant No. DE-FG02-06ER46309.

  7. Intensity ratio measurements for density sensitive lines of highly charged Fe ions

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Safdar, E-mail: safdaruetian@gmail.com; Shimizu, Erina [Institute for Laser Science, The University of Electro-Communications (Japan); Sakaue, Hiroyuki A.; Kato, Daiji; Murakami, Izumi [National Institute for Fusion Science (Japan); Yamamoto, Norimasa [Chubu University (Japan); Hara, Hirohisa; Watanabe, Tetsuya [The Graduate University of Advanced Studies (SOKENDAI) (Japan); Nakamura, Nobuyuki, E-mail: n-nakamu@ils.uec.ac.jp [Institute for Laser Science, The University of Electro-Communications (Japan)

    2015-11-15

    Intensity ratio of density sensitive emission lines emitted from Fe ions in the extreme ultraviolet region is important for astrophysics applications. We report high-resolution intensity ratio measurements for Fe ions performed at Tokyo EBIT laboratory by employing a flat-field grazing incidence spectrometer. The experimental intensity ratios of Fe X and Fe XII are plotted as a function of electron density for different electron beam currents. The experimental results are compared with the predicted intensity ratios from the model calculations.

  8. Reinvestigation of the charge density distribution in arc discharge fusion system

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Lin Horng; Yee, Lee Kim; Nan, Phua Yeong; Thung, Yong Yun; Khok, Yong Thian; Rahman, Faidz Abd [Centre of Photonics and Advance Material, Universiti Tunku Abdul Rahman Kuala Lumpur (Malaysia)

    2015-04-24

    A continual arc discharge system has been setup and the light intensity of arc discharge has been profiled. The mathematical model of local energy density distribution in arc discharge fusion has been simulated which is in good qualitative agreement with light intensity profile of arc discharge in the experiments. Eventually, the local energy density distribution of arc discharge system is able to be precisely manipulated to act as heat source in the fabrication of fused fiber devices.

  9. Demonstration of the difference Casimir force for samples with different charge carrier densities

    CERN Document Server

    Chen, F; Mohideen, U; Mostepanenko, V M

    2006-01-01

    A measurement of the Casimir force between a gold coated sphere and two Si plates of different carrier densities is performed using a high vacuum based atomic force microscope. The results are compared with the Lifshitz theory and good agreement is found. Our experiment demonstrates that by changing the carrier density of the semiconductor plate by several orders of magnitude it is possible to modify the Casimir interaction. This result may find applications in nanotechnology.

  10. Ions in mixed dielectric solvents: density profiles and osmotic pressure between charged interfaces.

    Science.gov (United States)

    Ben-Yaakov, Dan; Andelman, David; Harries, Daniel; Podgornik, Rudi

    2009-04-30

    The forces between charged macromolecules, usually given in terms of osmotic pressure, are highly affected by the intervening ionic solution. While in most theoretical studies the solution is treated as a homogeneous structureless dielectric medium, recent experimental studies concluded that, for a bathing solution composed of two solvents (binary mixture), the osmotic pressure between charged macromolecules is affected by the binary solvent composition. By adding local solvent composition terms to the free energy, we obtain a general expression for the osmotic pressure, in planar geometry and within the mean-field framework. The added effect is due to the permeability inhomogeneity and nonelectrostatic short-range interactions between the ions and solvents (preferential solvation). This effect is mostly pronounced at small distances and leads to a reduction in the osmotic pressure for macromolecular separations of the order 1-2 nm. Furthermore, it leads to a depletion of one of the two solvents from the charged macromolecules (modeled as planar interfaces). Lastly, by comparing the theoretical results with experimental ones, an explanation based on preferential solvation is offered for recent experiments on the osmotic pressure of DNA solutions.

  11. Nuclear charge and neutron radii and nuclear matter: Trend analysis in Skyrme density-functional-theory approach

    Science.gov (United States)

    Reinhard, P.-G.; Nazarewicz, W.

    2016-05-01

    Background: Radii of charge and neutron distributions are fundamental nuclear properties. They depend on both nuclear interaction parameters related to the equation of state of infinite nuclear matter and on quantal shell effects, which are strongly impacted by the presence of nuclear surface. Purpose: In this work, by studying the correlation of charge and neutron radii, and neutron skin, with nuclear matter parameters, we assess different mechanisms that drive nuclear sizes. Method: We apply nuclear density functional theory using a family of Skyrme functionals obtained by means of optimization protocols, which do not include any radius information. By performing the Monte Carlo sampling of reasonable functionals around the optimal parametrization, we scan all correlations between nuclear matter properties and observables characterizing charge and neutron distributions of spherical closed-shell nuclei 48Ca,208Pb, and 298Fl. Results: By considering the influence of various nuclear matter properties on charge and neutron radii in a multidimensional parameter space of Skyrme functionals, we demonstrate the existence of two strong relationships: (i) between the nuclear charge radii and the saturation density of symmetric nuclear matter ρ0, and (ii) between the neutron skins and the slope of the symmetry energy L . The impact of other nuclear matter properties on nuclear radii is weak or nonexistent. For functionals optimized to experimental binding energies only, proton and neutron radii are found to be weakly correlated due to canceling trends from different nuclear matter characteristics. Conclusion: The existence of only two strong relations connecting nuclear radii with nuclear matter properties has important consequences. First, by requiring that the nuclear functional reproduces the empirical saturation point of symmetric nuclear matter practically fixes the charge (or proton) radii, and vice versa. This explains the recent results of ab initio calculations

  12. Constraining the density dependence of the symmetry energy using the multiplicity and average pT ratios of charged pions

    Science.gov (United States)

    Cozma, M. D.

    2017-01-01

    The charged pion multiplicity ratio in intermediate-energy heavy-ion collisions, a probe of the density dependence of symmetry energy above the saturation point, has been proven in a previous study to be extremely sensitive to the strength of the isovector Δ (1232 ) potential in nuclear matter. As there is no knowledge, either from theory or experiment, about the magnitude of this quantity, the extraction of constraints on the slope of the symmetry energy at saturation by using exclusively the mentioned observable is hindered at present. It is shown that, by including the ratio of average pT of charged pions / in the list of fitted observables, the noted problem can be circumvented. A realistic description of this observable requires accounting for the interaction of pions with the dense nuclear matter environment by the incorporation of the so-called S -wave and P -wave pion optical potentials. This is performed within the framework of a quantum molecular dynamics transport model that enforces the conservation of the total energy of the system. It is shown that constraints on the slope of the symmetry energy at saturation density and the strength of the Δ (1232) potential can be simultaneously extracted. A symmetry energy with a value of the slope parameter L >50 MeV is favored, at 1 σ confidence level, from a comparison with published FOPI experimental data. A precise constraint will require experimental data more accurate than presently available, particularly for the charged pion multiplicity ratio, and better knowledge of the density and momentum dependence of the pion potential for the whole range of these two variables probed in intermediate-energy heavy-ion collisions.

  13. Flavor structure of the nucleon electromagnetic form factors and transverse charge densities in the chiral quark-soliton model

    CERN Document Server

    Silva, Antonio; Kim, Hyun-Chul

    2013-01-01

    We investigate the flavor decomposition of the electromagnetic form factors of the nucleon, based on the chiral quark-soliton model with symmetry-conserving quantization. We consider the rotational 1/N_c and linear strange-quark mass (m_s) corrections. To extend the results to higher momentum transfer, we take into account the kinematical relativistic effects. We discuss the results of the flavor-decomposed electromagnetic form factors in comparison with the recent experimental data. In order to see the effects of the strange quark, we compare the SU(3) results with those of SU(2). We finally discuss the transverse charge densities for both unpolarized and polarized nucleons.

  14. Pressure-induced quenching of the charge-density-wave state observed by x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Sacchetti, A.

    2010-05-03

    We report an x-ray diffraction study on the charge-density-wave (CDW) LaTe{sub 3} and CeTe{sub 3} compounds as a function of pressure. We extract the lattice constants and the CDW modulation wave-vector, and provide direct evidence for a pressure-induced quenching of the CDW phase. We observe subtle differences between the chemical and mechanical compression of the lattice. We account for these with a scenario where the effective dimensionality in these CDW systems is dependent on the type of lattice compression and has a direct impact on the degree of Fermi surface nesting and on the strength of fluctuation effects.

  15. Unconventional Charge-Density Wave in the Organic Conductor α-(BEDT-TTF)2KHg(SCN)4

    Science.gov (United States)

    Maki, Kazumi; Dóra, Balázs; Kartsovnik, Mark; Virosztek, Attila; Korin-Hamzić, Bojana; Basletić, Mario

    2003-06-01

    The low temperature phase (LTP) of α-(BEDT-TTF)2KHg(SCN)4 salt is known for its surprising angular dependent magnetoresistance (ADMR), which has been studied intensively in the last decade. However, the nature of the LTP has not been understood until now. Here we analyze theoretically ADMR in unconventional (or nodal) charge-density wave (UCDW). In magnetic field the quasiparticle spectrum in UCDW is quantized, which gives rise to spectacular ADMR. The present model accounts for many striking features of ADMR data in α-(BEDT-TTF)2KHg(SCN)4.

  16. Optical Properties of the Charge-Density-Wave Polychalcogenide Compounds R2Te5 (R=Nd, Sm and Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Pfuner, F.; Degiorgi, L.; /Zurich, ETH; Shin, K.Y.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2010-02-15

    We investigate the rare-earth polychalcogenide R{sub 2}Te{sub 5} (R = Nd, Sm and Gd) charge-density-wave (CDW) compounds by optical methods. From the absorption spectrum we extract the excitation energy of the CDW gap and estimate the fraction of the Fermi surface which is gapped by the formation of the CDW condensate. In analogy to previous findings on the related RTe{sub n} (n = 2 and 3) families, we establish the progressive closing of the CDW gap and the moderate enhancement of the metallic component upon chemically compressing the lattice.

  17. The 181Ta Nuclear Quadrupole Interaction in the Charge Density Wave Phases of 1T-TaS2

    Science.gov (United States)

    Ganal, P.; Butz, T.; Lerf, A.; Naito, M.; Nishihara, H.

    1990-04-01

    With a high resolution time differential perturbed angular correlation spectrometer we investigated the nuclear quadrupole interaction of Ta in 1T-TaS2 . The results obtained for the commensurate charge density wave phase lead to a revised assignment of the previously observed 181Ta NQR resonances. Differences in the intracluster architecture of the 13-atom Star of David cluster between 1T-TaS2 and 1T-TaSe2 could be responsible for the metal to semiconductor transition which occurs in lT-TaS2 but not in lT-TaSe2 .

  18. The density functional study of electronic structure, electronic charge density, linear and nonlinear optical properties of single crystal alpha-LiAlTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A.H. [New Technologies-Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Khan, Wilayat, E-mail: walayat76@gmail.com [New Technologies-Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic)

    2014-04-01

    Highlights: • FP-LAPW technique is used for calculating the electronic structure. • The band structure shows that the calculated compound is semiconductor. • The complex dielectric function has been calculated. • Nonlinear optical properties has also been calculated. • This compound can be used for molecular engineering of the crystals. - Abstract: Self-consistent calculations is performed using the full potential linear augmented plane wave (FP-LAPW) technique based on density functional theory (DFT) to investigate the electronic band structure, density of states, electronic charge density, linear and non-linear optical properties of α-LiAlTe{sub 2} compound having tetragonal symmetry with space group I4{sup ¯}2d. The electronic structure are calculated using the Ceperley Alder local density approach (CA-LDA), Perdew Burke and Ernzerhof generalize gradient approach (PBE-GGA), Engel–Vosko generalize gradient approach (EVGGA) and modified Becke Johnson approach (mBJ). Band structure calculations of (α-LiAlTe{sub 2}) depict semiconducting nature with direct band gap of 2.35 eV (LDA), 2.48 eV (GGA), 3.05 eV (EVGGA) and 3.13 eV (mBJ), which is comparable to experimental value. The calculated electronic charge density show ionic interaction between Te and Li atoms and polar covalent interaction between Al and Te atoms. Some optical susceptibilities like dielectric constants, refractive index, extension co-efficient, reflectivity and energy loss function have been calculated and analyzed on the basis of electronic structure. The compound α-LiAlTe{sub 2} provides a considerable negative value of birefringence of −0.01. Any anisotropy observed in the linear optical properties which are in favor to enhance the nonlinear optical properties. The symbol χ{sub abc}{sup (2)}(ω) represents the second order nonlinear optical susceptibilities, possess six non-zero components in this symmetry (tetragonal), called: 1 2 3, 2 1 3, 2 3 1, 1 3 2, 3 1 2 and 3 2 1

  19. Chemical bonding and charge density distribution analysis of undoped and lanthanum doped barium titanate ceramics

    Indian Academy of Sciences (India)

    J MANGAIYARKKARASI; R SARAVANAN; MUKHLIS M ISMAIL

    2016-12-01

    A-site deficient, Lanthanum substituted Ba1−xLa2x/3TiO3 (x=0.000, 0.005, 0.015, 0.020 and 0.025) ceramics have been synthesized by chemical route. The effects of lanthanum dopant on the BaTiO3 lattice and the electron density distributions in the unit cell of the samples were investigated. Structural studies suggested the reduction in cell parameters and shrinkage in cell volume with the increase in lanthanum content. Chemical bonding and electron density distributions were examined through high resolution maximum entropy method (MEM). The mid bond electron density values revealed the enhancement of covalent nature between titanium and oxygen ions and predominant ionic nature between barium and oxygen ions. Average grain sizes were estimated for the undoped and doped samples. SEM investigations showed the existence of smaller grains with large voids in between them.

  20. High charge carrier density at the NaTaO3/SrTiO3 hetero-interface

    KAUST Repository

    Nazir, Safdar

    2011-08-05

    The formation of a (quasi) two-dimensional electron gas between the band insulators NaTaO3 and SrTiO3 is studied by means of the full-potential linearized augmented plane-wave method of density functional theory. Optimization of the atomic positions points to only small changes in the chemical bonding at the interface. Both the p-type (NaO)−/(TiO2)0 and n-type (TaO2)+/(SrO)0 interfaces are found to be metallic with high charge carrier densities. The effects of O vacancies are discussed. Spin-polarized calculations point to the formation of isolated O 2pmagnetic moments, located in the metallic region of the p-type interface.

  1. Pseudorapidity density of charged particles p-Pb collisions at $\\sqrt{s_{NN}}$ = 5.02 TeV

    CERN Document Server

    Abelev, Betty; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agocs, Andras Gabor; Agostinelli, Andrea; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahn, Sang Un; Ahn, Sul-Ah; Ajaz, Muhammad; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Arend, Andreas; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Asryan, Andzhey; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldini Ferroli, Rinaldo; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, Francesco; Blanco, F; Blau, Dmitry; Blume, Christoph; Boccioli, Marco; Boettger, Stefan; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bossu, Francesco; Botje, Michiel; Botta, Elena; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Busch, Oliver; Buthelezi, Edith Zinhle; Caballero Orduna, Diego; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Wisla; Carena, Francesco; Carlin Filho, Nelson; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Castillo Hernandez, Juan Francisco; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chawla, Isha; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Coccetti, Fabrizio; Colamaria, Fabio; Colella, Domenico; Collu, Alberto; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Connors, Megan Elizabeth; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crescio, Elisabetta; Crochet, Philippe; Cruz Alaniz, Emilia; Cuautle, Eleazar; Cunqueiro, Leticia; Dainese, Andrea; Dalsgaard, Hans Hjersing; Danu, Andrea; Das, Kushal; Das, Indranil; Das, Supriya; Das, Debasish; Dash, Sadhana; Dash, Ajay Kumar; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; Delagrange, Hugues; Deloff, Andrzej; De Marco, Nora; Denes, Ervin; De Pasquale, Salvatore; Deppman, Airton; D'Erasmo, Ginevra; de Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Di Bari, Domenico; Dietel, Thomas; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Donigus, Benjamin; Dordic, Olja; Driga, Olga

    2013-01-01

    The charged-particle pseudorapidity density measured over 4 units of pseudorapidity in non-single-diffractive (NSD) p-Pb collisions at a centre-of-mass energy per nucleon pair $\\sqrt{s_{NN}}$ = 5.02 TeV is presented. The average value at midrapidity is measured to be 16.81 $\\pm$ 0.71 (syst.), which corresponds to 2.14 $\\pm$ 0.17 (syst.) per participating nucleon. This is 16% lower than in NSD pp collisions interpolated to the same collision energy, and 84% higher than in d-Au collisions at $\\sqrt{s_{NN}}$ = 0.2 TeV. The measured pseudorapidity density in p-Pb collisions is compared to model predictions, and provides new constraints on the description of particle production in high-energy nuclear collisions.

  2. Standard hydrogen electrode and potential of zero charge in density functional calculations

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Björketun, Mårten; Skúlason, Egill

    2011-01-01

    Methods to explicitly account for half-cell electrode potentials have recently appeared within the framework of density functional theory. The potential of the electrode relative to the standard hydrogen electrode is typically determined by subtracting the experimental value of the absolute......) the calculated work function strongly depends on the structure of the water film covering the metal surface. In this paper, we first identify the most accurate experimental reference for the ASHEP by revisiting up-to-date literature, and validate the choice of electron reference level in single-electrode density...

  3. ‘Living’ PEGylation on gold nanoparticles to optimize cancer cell uptake by controlling targeting ligand and charge densities

    Science.gov (United States)

    Chen, Hongwei; Paholak, Hayley; Ito, Masayuki; Sansanaphongpricha, Kanokwan; Qian, Wei; Che, Yong; Sun, Duxin

    2013-09-01

    We report and demonstrate biomedical applications of a new technique—‘living’ PEGylation—that allows control of the density and composition of heterobifunctional PEG (HS-PEG-R; thiol-terminated poly(ethylene glycol)) on gold nanoparticles (AuNPs). We first establish ‘living’ PEGylation by incubating HS-PEG5000-COOH with AuNPs (˜20 nm) at increasing molar ratios from zero to 2000. This causes the hydrodynamic layer thickness to differentially increase up to 26 nm. The controlled, gradual increase in PEG-COOH density is revealed after centrifugation, based on the ability to re-suspend the pellet and increase the AuNP absorption. Using a fluorescamine-based assay we quantify differential HS-PEG5000-NH2 binding to AuNPs, revealing that it is highly efficient until AuNP saturation is reached. Furthermore, the zeta potential incrementally changes from -44.9 to +52.2 mV and becomes constant upon saturation. Using ‘living’ PEGylation we prepare AuNPs with different ratios of HS-PEG-RGD (RGD: Arg-Gly-Asp) and incubate them with U-87 MG (malignant glioblastoma) and non-target cells, demonstrating that targeting ligand density is critical to maximizing the efficiency of targeting of AuNPs to cancer cells. We also sequentially control the HS-PEG-R density to develop multifunctional nanoparticles, conjugating positively charged HS-PEG-NH2 at increasing ratios to AuNPs containing negatively charged HS-PEG-COOH to reduce uptake by macrophage cells. This ability to minimize non-specific binding/uptake by healthy cells could further improve targeted nanoparticle efficacy.

  4. Charge-constrained auxiliary-density-matrix methods for the Hartree–Fock exchange contribution

    DEFF Research Database (Denmark)

    Merlot, Patrick; Izsak, Robert; Borgoo, Alex;

    2014-01-01

    Three new variants of the auxiliary-density-matrix method (ADMM) of Guidon, Hutter, and VandeVondele [J. Chem. Theory Comput. 6, 2348 (2010)] are presented with the common feature thatthey have a simplified constraint compared with the full orthonormality requirement of the earlier ADMM1 method...

  5. Energy and Centrality Dependences of Charged Multiplicity Density in Relativistic Nuclear Collisions

    Institute of Scientific and Technical Information of China (English)

    SA; Ben-hao; Bonasera; A; TAI; An

    2002-01-01

    Using a hadron and string cascade model, JPCIAE, the energy and centrality dependences of chargedparticle pseudo rapidity density in relativistic nuclear collisions were studied. Within the framework ofthis model, both the relativistic p + p experimental data and the PHOBOS and PHENIX Au + Au data at

  6. Cell-penetrating compounds preferentially bind glycosaminoglycans over plasma membrane lipids in a charge density- and stereochemistry-dependent manner.

    Science.gov (United States)

    Prevette, Lisa E; Benish, Nicolas C; Schoenecker, Amber R; Braden, Kristin J

    2015-12-01

    Cell-penetrating compounds (CPCs) are often conjugated to drugs and genes to facilitate cellular uptake. We hypothesize that the electrostatic interaction between the positively charged amines of the cell-penetrating compounds and the negatively charged glycosaminoglycans (GAGs) extending from cell surfaces is the initiating step in the internalization process. The interactions of generation 5 PAMAM dendrimer, Tat peptide and 25 kDa linear PEI with four different GAGs have been studied using isothermal titration calorimetry to elucidate structure-function relationships that could lead to improved drug and gene delivery methods to a wide variety of cell types. Detailed thermodynamic analysis has determined that CPC-GAG binding constants range from 8.7×10(3) to 2.4×10(6)M(-1) and that affinity is dependent upon GAG charge density and stereochemistry and CPC molecular weight. The effect of GAG composition on affinity is likely due to hydrogen bonding between CPC amines and amides and GAG hydroxyl and amine groups. These results were compared to the association of CPCs with lipid vesicles of varying composition as model plasma membranes to finally clarify the relative importance of each cell surface component in initial cell recognition. CPC-lipid affinity increases with anionic lipid content, but GAG affinity is higher for all cell-penetrating compounds, confirming the role these heterogeneous polysaccharides play in cellular association and clustering.

  7. Artificial Modulation of Ferroelectric Thin Films into Antiferroelectric through H+ Implantation for High-Density Charge Storage

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-Jun; FEI Jin-Wen; TANG Wing-Ao; JIANG An-Quan

    2008-01-01

    Hydrogen ions are implanted into Pb(Zr0.3Ti0.7)O3 thin films at the energy of 40keV with a flux of 5 ×1014 ions/cm2.Pseudo-antiferroelectric behaviour in the implanted thin films is observed,as confirmed by the measurements of polarization versus electric hysteresis loops and capacitance versus voltage curves.X-ray diffraction patterns show the film structures before and after H+ implantation both to be perovskite of a tetragonal symmetry.These findings indicate that hydrogen ions exist as stable dopants within the films.It is believed that the dopants change domain-switching behaviour via the boundary charge compensation.Meanwhile,time dependence of leakage current density after time longer than lOs indicates the enhancement of the leakage current nearly in one order for the implanted film,but the current at time shorter than I s is mostly the same as that of the original film without the ionic implantation.The artificial tailoring of the antiferroelectric behaviour through H+ implantation in ferroelectric thin films is finally proven to be achievable for the device application of high-density charge storage.

  8. Impact of quenched oxygen disorder on charge density wave order in YBa2Cu3O6+x.

    Science.gov (United States)

    Achkar, A J; Mao, X; McMahon, Christopher; Sutarto, R; He, F; Liang, Ruixing; Bonn, D A; Hardy, W N; Hawthorn, D G

    2014-09-05

    The competition between superconductivity and charge density wave (CDW) order in underdoped cuprates has now been widely reported, but the role of disorder in this competition has yet to be fully resolved. A central question is whether disorder sets the length scale of the CDW order, for instance by pinning charge density fluctuations or disrupting an otherwise long-range order. Using resonant soft x-ray scattering, we investigate the sensitivity of CDW order in YBa2Cu3O6+x (YBCO) to varying levels of oxygen disorder. We find that quench cooling YBCO6.67 (YBCO6.75) crystals to destroy their o-V and o-VIII (o-III) chains decreases the intensity of the CDW superlattice peak by a factor of 1.9 (1.3), but has little effect on the CDW correlation length, incommensurability, and temperature dependence. This reveals that while quenched oxygen disorder influences the CDW order parameter, the spatial extent of the CDW order is insensitive to the level of quenched oxygen disorder and may instead be a consequence of competition with superconductivity.

  9. Optimization of tetravalent manganese feroxyhyte's negative charge density: A high-performing mercury adsorbent from drinking water.

    Science.gov (United States)

    Kokkinos, E; Simeonidis, K; Pinakidou, F; Katsikini, M; Mitrakas, M

    2017-01-01

    This study demonstrates an optimization procedure for the development of an Hg-specified adsorbent able to comply with the regulation limit for drinking water of 1μg/L. On this purpose, the synthesis of Mn(IV)-feroxyhyte was modified to achieve high negative charge density by combining alkaline and extreme oxidizing conditions. In particular, precipitation of FeSO4 at pH9 and excess of KMnO4 follows a very fast nucleation step providing a product with very small nanocrystal size (1-2nm), high specific surface area (300m(2)/g) and maximum negative charge density (1.8mmol H(+)/g). The adsorbent was validated for Hg removal in batch experiments and column tests using natural-like water indicating an adsorption capacity as high as 2.5μg/mg at equilibrium concentration 1μg/L under reliable conditions of application. Importantly, the adsorption is an exothermic spontaneous process, resulting in the formation of inner sphere complexes by sharing both A-type and B-type oxygen atoms with the metal surface octahedral as revealed by the X-ray absorption fine structure results. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. AB-INITIO STUDY OF BULK MODULUS AND CHARGE DENSITY OF CUBIC SrMO3 PEROVSKITES (M = Ti, Zr, Mo, Rh, Ru

    Directory of Open Access Journals (Sweden)

    AVINASH DAGA

    2012-03-01

    Full Text Available Bulk modulus & charge density of cubic SrMO3 perovskites (M = Ti, Zr, Mo, Rh & Ru have been investigated systematically using the first principle density functional calculations. Local density approximation (LDAmethod has been used to compute the two quantities for five perovskites. It is found that the calculated bulk modulus for all the transition metal oxides are in good agreement with the available experimental data and with other theoretical results previously reported in the literature. ABINIT computer code is used to carry out all the calculations. Charge density plots for all the five cubic SrMO3 perovskites have been drawn using MATLAB. The maximum and minimum values of charge density along with the corresponding reduced coordinates are reported for all the perovskites.

  11. Charge carrier density at the (Na/K)TaO{sub 3}/SrTiO{sub 3} interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Schwingenschloegl, Udo; Nazir, Safdar [KAUST, PSE Division, Thuwal 23955-6900, Kingdom of Saudi Arabia (Saudi Arabia)

    2012-07-01

    The formation of a quasi two-dimensional electron gas between the band insulators NaTaO{sub 3} and SrTiO{sub 3} as well as KTaO{sub 3} and SrTiO{sub 3} is studied by means of the full-potential linearized augmented plane-wave method of density functional theory. Optimization of the atomic positions points to only small changes in the chemical bonding at the interface. The creation of metallic interface states thus is not affected by structural relaxation but can be explained by charge transfer between transition metal and oxygen atoms. It is to be expected that a charge transfer is likewise important for related interfaces such as LaAlO{sub 3}/SrTiO{sub 3}. Both the p-type (NaO){sup -}/(TiO{sub 2}){sup 0} and n-type (TaO{sub 2}){sup +}/(SrO){sup 0} interfaces in NaTaO{sub 3}/SrTiO{sub 3} are found to be metallic with strongly enhanced charge carrier densities as compared to the respective interfaces in KTaO{sub 3}/SrTiO{sub 3}. The effects of O vacancies are discussed. Spin-polarized calculations point to the formation of isolated O 2p magnetic moments, located in the metallic region of the p-type interface. The systems under investigation are suitable for disentangling the complex behavior of metallic interface states, since the structural relaxation is small.

  12. Measurement of the charged pion mass using a low-density target of light atoms

    Directory of Open Access Journals (Sweden)

    Trassinelli M.

    2016-01-01

    Full Text Available We present a new evaluation of the negatively charged pion mass based on the simultaneous spectroscopy of pionic nitrogen and muonic oxygen transitions using a gaseous target composed by a N2/O2 mixture at 1.4 bar. We present the experimental set-up and the methods for deriving the pion mass value from the spatial separation from the 5g − 4f πN transition line and the 5g − 4f μO transition line used as reference. Moreover, we discuss the importance to use dilute targets in order to minimize the influence of additional spectral lines from the presence of remaining electrons during the radiative emission. The occurrence of possible satellite lines is investigated via hypothesis testing methods using the Bayes factor.

  13. Measurement of the charged pion mass using a low-density target of light atoms

    CERN Document Server

    Trassinelli, M; Borchert, G; Dax, A; Egger, J -P; Gotta, D; Hennebach, M; Indelicato, P; Liu, Y -W; Manil, B; Nelms, N; Simons, L M; Wells, A

    2016-01-01

    We present a new evaluation of the negatively charged pion mass based on the simultaneous spec-troscopy of pionic nitrogen and muonic oxygen transitions using a gaseous target composed by a N 2 /O 2 mixture at 1.4 bar. We present the experimental setup and the methods for deriving the pion mass value from the spatial separation from the 5g -- 4 f $\\pi$N transition line and the 5g -- 4 f $\\mu$O transition line used as reference. Moreover, we discuss the importance to use dilute targets in order to minimize the influence of additional spectral lines from the presence of remaining electrons during the radiative emission. The occurrence of possible satellite lines is investigated via hypothesis testing methods using the Bayes factor.

  14. Ionic Strength, Surface Charge, and Packing Density Effects on the Properties of Peptide Self-Assembled Monolayers.

    Science.gov (United States)

    Leo, Norman; Liu, Juan; Archbold, Ian; Tang, Yongan; Zeng, Xiangqun

    2017-02-28

    The various environmental parameters of packing density, ionic strength, and solution charge were examined for their effects on the properties of the immobilized peptide mimotope CH19 (CGSGSGSQLGPYELWELSH) that binds with the therapeutic antibody Trastuzumab (Herceptin) on a gold substrate. The immobilization of CH19 onto gold was examined with a quartz crystal microbalance (QCM). The QCM data showed the presence of intermolecular interactions resulting in the increase of viscoelastic properties of the peptide self-assembled monolayer (SAM). The CH19 SAM was diluted with CS7 (CGSGSGS) to decrease the packing density as CH19/CS7. The packing density and ionic strength parameters were evaluated by atomic force microscopy (AFM), ellipsometry, and QCM. AFM and ellipsometry showed a distinct conformational difference between CH19 and CH19/CS7, indicating a relationship between packing density and conformational state of the immobilized peptide. The CH19 SAM thickness was 40 Å with a rough topology, while the CH19/CS7 SAM thickness was 20 Å with a smooth topology. The affinity studies showed that the affinity of CH19 and CH19/CS7 to Trastuzumab were both on the order of 10(7) M(-1) in undiluted PBS buffer, while the dilution of the buffer by 1000× increased both SAMs affinities to Trastuzumab to the order of 10(15) M(-2) and changed the binding behavior from noncooperative to cooperative binding. This indicated that ionic strength had a more pronounced effect on binding properties of the CH19 SAM than packing density. Electrochemical impedance spectroscopy (EIS) was conducted on the CH19/CS7 SAM, which showed an increase in impedance after each EIS measurement cycle. Cyclic voltammetry on the CH19/CS7 SAM decreased impedance to near initial values. The impact of the packing density, buffer ionic strength, and local charge perturbation of the peptide SAM properties was interpreted based on the titratable sites in CH19 that could participate in the proton transfer and

  15. Volumetric Pricing of Agricultural Water Supplies: A Case Study

    Science.gov (United States)

    Griffin, Ronald C.; Perry, Gregory M.

    1985-07-01

    Models of water consumption by rice producers are conceptualized and then estimated using cross-sectional time series data obtained from 16 Texas canal operators for the years 1977-1982. Two alternative econometric models demonstrate that both volumetric and flat rate water charges are strongly and inversely related to agricultural water consumption. Nonprice conservation incentives accompanying flat rates are hypothesized to explain the negative correlation of flat rate charges and water consumption. Application of these results suggests that water supply organizations in the sample population converting to volumetric pricing will generally reduce water consumption.

  16. The Beam-Density Effect on Energy Loss of a Relativistic Charged Particle Beam.

    Science.gov (United States)

    1983-09-01

    media. t iU NSWC TR 83-348 Folloving the method developed by Sternheimer 24 in his calculations of the Fermi density effect, i l L2 -2in.v-v 2 (2.16...where Z 2v 2 + f.. The Sternheimer factor P is chosen so that the i i i value of the Bethe logarithm, InI, obtained in non-relativistic experiments, is...first three eigenfrequencies were taken from Reference 25. A more recent set has been given by Sternheimer and Peierls,2 6 but the ones of Reference 25

  17. Universal bulk charge-density-wave (CDW) correlations in the cuprate superconductors

    Science.gov (United States)

    Tabis, Wojciech

    2014-03-01

    The recent observation of bulk CDW order in YBa2Cu3O8+δ(YBCO) in competition with superconductivity is a significant development. Using Cu L-edge resonant X-ray scattering, we also observe bulk CDW order in HgBa2CuO4+δ(Hg1201 Tc = 72K). The correlations appear below TCDW ~ 200K, well below the pseudogap temperature T* ~ 320K associated with unusual magnetism, but coincident with the onset of Fermi-liquid-like charge transport. In contrast to YBCO, we observe no decrease of the CDW amplitude below Tc, and the correlation length is short and temperature independent. CDW correlations therefore are a universal property of underdoped cuprates, enhanced by low structural symmetry and a magnetic field, but fundamentally not in significant competition with superconductivity. We also discuss the relationship between the CDW modulation wave vector and the Fermi surface area extracted from QO experiments. Work supported by DOE-BES. In collaboration with Y. Li, M. Le Tacon, L. Braicovich, A. Kreyssig, M. Minola, G. Dellea, E. Weschke, M. Veit, A. Goldman, T. Schmitt, G. Ghiringhelli, N. Barisic, M.K. Chan, C. Dorow, G. Yu, X. Zhao, B. Keimer, M. Greven.

  18. Electronic and atomic structures of the Sr3Ir4Sn13 single crystal: A possible charge density wave material

    Science.gov (United States)

    Wang, H.-T.; Srivastava, M. K.; Wu, C.-C.; Hsieh, S.-H.; Wang, Y.-F.; Shao, Y.-C.; Liang, Y.-H.; Du, C.-H.; Chiou, J.-W.; Cheng, C.-M.; Chen, J.-L.; Pao, C.-W.; Lee, J.-F.; Kuo, C. N.; Lue, C. S.; Wu, M.-K.; Pong, W.-F.

    2017-01-01

    X-ray scattering (XRS), x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopic techniques were used to study the electronic and atomic structures of the high-quality Sr3Ir4Sn13 (SIS) single crystal below and above the transition temperature (T* ≈ 147 K). The evolution of a series of modulated satellite peaks below the transition temperature in the XRS experiment indicated the formation of a possible charge density wave (CDW) in the (110) plane. The EXAFS phase derivative analysis supports the CDW-like formation by revealing different bond distances [Sn1(2)-Sn2] below and above T* in the (110) plane. XANES spectra at the Ir L3-edge and Sn K-edge demonstrated an increase (decrease) in the unoccupied (occupied) density of Ir 5d-derived states and a nearly constant density of Sn 5p-derived states at temperatures T atomic structures and the CDW-like phase in the SIS single crystal. PMID:28106144

  19. Modeling environmental effects on charge density distributions in polar organometallics: validation of embedded cluster models for the methyl lithium crystal.

    Science.gov (United States)

    Götz, Kathrin; Meier, Florian; Gatti, Carlo; Burow, Asbjörn M; Sierka, Marek; Sauer, Joachim; Kaupp, Martin

    2010-11-15

    The charge density and its Laplacian at the Li-C and C-H bond critical points and other features of the electron density distribution of the methyl lithium crystal have been compared by density functional methods for (i) the isolated (LiCH(3))(4) tetramer or larger clusters, (ii) for quantum mechanically treated clusters in polarizable continuum model (PCM) surroundings, (iii) for clusters augmented by the periodic electrostatic embedded cluster model (PEECM), and for (iv) the periodic crystal. Comparisons with identical functional and basis sets indicate that both PCM and PEECM embedding of only a tetramer did not fully account for the environmental effect. In contrast, embedding of a full unit cell gave results that were essentially converged to the periodic crystal data. Effects of basis set and exchange correlation functional on the QTAIM bond descriptors are of a comparable order of magnitude as the crystal environmental effects. In this context, embedded cluster computations provide distinct advantages over explicit solid-state calculations with respect to their freedom of the choice of computational and theoretical level. This is demonstrated by embedded MP2 calculations.

  20. Flexible Volumetric Structure

    Science.gov (United States)

    Cagle, Christopher M. (Inventor); Schlecht, Robin W. (Inventor)

    2014-01-01

    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure.

  1. Multiband nodeless superconductivity near the charge-density-wave quantum critical point in ZrTe3-x Sex

    Institute of Scientific and Technical Information of China (English)

    崔珊; 何兰坡; 洪晓晨; 朱相德; Cedomir Petrovic; 李世燕

    2016-01-01

    It was found that selenium doping can suppress the charge-density-wave (CDW) order and induce bulk supercon-ductivity in ZrTe3. The observed superconducting dome suggests the existence of a CDW quantum critical point (QCP) in ZrTe3−x Sex near x≈0.04. To elucidate the superconducting state near the CDW QCP, we measure the thermal conductivity of two ZrTe3−x Sex single crystals (x=0.044 and 0.051) down to 80 mK. For both samples, the residual linear termκ0/T at zero field is negligible, which is a clear evidence for nodeless superconducting gap. Furthermore, the field dependence ofκ0/T manifests a multigap behavior. These results demonstrate multiple nodeless superconducting gaps in ZrTe3−x Sex , which indicates conventional superconductivity despite of the existence of a CDW QCP.

  2. d-Wave Superconductivity and s-Wave Charge Density Waves: Coexistence between Order Parameters of Different Origin and Symmetry

    Directory of Open Access Journals (Sweden)

    Alexander I. Voitenko

    2011-10-01

    Full Text Available A review of the theory describing the coexistence between d-wave superconductivity and s-wave charge-density-waves (CDWs is presented. The CDW gapping is identified with pseudogapping observed in high-Tc oxides. According to the cuprate specificity, the analysis is carried out for the two-dimensional geometry of the Fermi surface (FS. Phase diagrams on the σ0 − α plane—here, σ0 is the ratio between the energy gaps in the parent pure CDW and superconducting states, and the quantity 2α is connected with the degree of dielectric (CDW FS gapping—were obtained for various possible configurations of the order parameters in the momentum space. Relevant tunnel and photoemission experimental data for high-Tc oxides are compared with theoretical predictions. A brief review of the results obtained earlier for the coexistence between s-wave superconductivity and CDWs is also given.

  3. Constraints on rapidity-dependent initial conditions from charged particle pseudorapidity densities and two-particle correlations

    CERN Document Server

    Ke, Weiyao; Bernhard, Jonah E; Bass, Steffen A

    2016-01-01

    We study the initial three-dimensional spatial configuration of the quark-gluon plasma produced in relativistic heavy-ion collisions using centrality and rapidity-dependent measurements of charged particle pseudorapidity densities and two-particle correlations. A cumulant-generating function is used to parametrize the rapidity dependence of local entropy deposition and extend arbitrary boost-invariant initial conditions to nonzero beam rapidities. The model is compared to p+Pb and Pb+Pb single-particle distributions and systematically optimized using Bayesian parameter estimation to extract high-probability initial condition parameters. The optimized initial conditions are then compared to a number of experimental observables including two-particle rapidity correlations, the rapidity dependence of anisotropic flow, and event-plane decorrelations.

  4. Remarkable Stability of Charge Density Wave Order in La1.875 Ba0.125 CuO4

    Science.gov (United States)

    Chen, X. M.; Thampy, V.; Mazzoli, C.; Barbour, A. M.; Miao, H.; Gu, G. D.; Cao, Y.; Tranquada, J. M.; Dean, M. P. M.; Wilkins, S. B.

    2016-10-01

    The occurrence of charge-density-wave (CDW) order in underdoped cuprates is now well established, although the precise nature of the CDW and its relationship with superconductivity is not. Theoretical proposals include contrasting ideas such as that pairing may be driven by CDW fluctuations or that static CDWs may intertwine with a spatially modulated superconducting wave function. We test the dynamics of CDW order in La1.825 Ba0.125 CuO4 by using x-ray photon correlation spectroscopy at the CDW wave vector, detected resonantly at the Cu L3 edge. We find that the CDW domains are strikingly static, with no evidence of significant fluctuations up to 2 ¾ h . We discuss the implications of these results for some of the competing theories.

  5. Remarkable Stability of Charge Density Wave Order in La_{1.875}Ba_{0.125}CuO_{4}.

    Science.gov (United States)

    Chen, X M; Thampy, V; Mazzoli, C; Barbour, A M; Miao, H; Gu, G D; Cao, Y; Tranquada, J M; Dean, M P M; Wilkins, S B

    2016-10-14

    The occurrence of charge-density-wave (CDW) order in underdoped cuprates is now well established, although the precise nature of the CDW and its relationship with superconductivity is not. Theoretical proposals include contrasting ideas such as that pairing may be driven by CDW fluctuations or that static CDWs may intertwine with a spatially modulated superconducting wave function. We test the dynamics of CDW order in La_{1.825}Ba_{0.125}CuO_{4} by using x-ray photon correlation spectroscopy at the CDW wave vector, detected resonantly at the Cu L_{3} edge. We find that the CDW domains are strikingly static, with no evidence of significant fluctuations up to 2 ¾  h. We discuss the implications of these results for some of the competing theories.

  6. Charged-Particle Thermonuclear Reaction Rates: II. Tables and Graphs of Reaction Rates and Probability Density Functions

    CERN Document Server

    Iliadis, Christian; Champagne, Art; Coc, Alain; Fitzgerald, Ryan

    2010-01-01

    Numerical values of charged-particle thermonuclear reaction rates for nuclei in the A=14 to 40 region are tabulated. The results are obtained using a method, based on Monte Carlo techniques, that has been described in the preceding paper of this series (Paper I). We present a low rate, median rate and high rate which correspond to the 0.16, 0.50 and 0.84 quantiles, respectively, of the cumulative reaction rate distribution. The meaning of these quantities is in general different from the commonly reported, but statistically meaningless expressions, "lower limit", "nominal value" and "upper limit" of the total reaction rate. In addition, we approximate the Monte Carlo probability density function of the total reaction rate by a lognormal distribution and tabulate the lognormal parameters {\\mu} and {\\sigma} at each temperature. We also provide a quantitative measure (Anderson-Darling test statistic) for the reliability of the lognormal approximation. The user can implement the approximate lognormal reaction rat...

  7. Time-dependent Ginzburg–Landau equation of charge-density-waves and numerical simulation of the sliding

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Masahiko, E-mail: m-hayashi@ed.akita-u.ac.jp [Faculty of Education and Human Studies, Akita University, Akita 010-8502 (Japan); Takane, Yositake [Department of Quantum Matter, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Ebisawa, Hiromichi [Institute of Liberal Arts and Sciences, Tohoku University, Sendai 980-8576 (Japan)

    2015-03-01

    Time-dependent Ginzburg–Landau equation (TDGL) for charge-density-wave (CDW) conductors is discussed. At first, we study a purely one-dimensional case, where the current electrodes are attached from the sides. One of the characteristics of our TDGL is that the non-equilibrium chemical potential for right-moving and left-moving electrons are taken into account as dynamical variables. Then the dynamical interaction between the condensate and the quasiparticles is demonstrated in an apparent form. We present some results of the numerical simulation of the sliding of CDW based on our TDGL. Possible extension to quasi-one dimensional (three-dimensional) systems is also discussed.

  8. Electronic structure of novel charge transfer compounds: application of Fermi orbital self-interaction corrected density functional theory

    Science.gov (United States)

    Hahn, Torsten; Rückerl, Florian; Liebing, Simon; Pederson, Mark

    We present our experimental and theoretical results on novel Picene/F4TCNQ and Manganese-Phthalocyanine/F4TCNQ donor / acceptor systems. We apply the recently developed Fermi-orbital based approach for self-interaction corrected density functional theory (FO-SIC DFT) to these materials and compare the results to standard DFT calculations and to experimental data obtained by photoemission spectroscopy. We focus our analysis on the description of the magnitude of the ground state charge transfer and on the details of the formed hybrid orbitals. Further, we show that for weakly bound donor / acceptor systems the FO-SIC approach delivers a more realistic description of the electronic structure compared to standard DFT calculations Support by DFG FOR1154 is greatly acknowledged.

  9. Aharonov-Anandan effect induced by spin-orbit interaction and charge-density waves in mesoscopic rings

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Y.; Bishop, A.R. [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1998-08-01

    We study the spin-dependent geometric phase effect in mesoscopic rings of charge-density-wave (CDW) materials. When electron spin is explicitly taken into account, we show that the spin-dependent Aharonov-Casher phase can have pronounced frustration effects on such CDW materials with appropriate electron filling. We show that this frustration has observable consequences for transport experiments. We identify a phase transition from a Peierls insulator to metal, which is induced by spin-dependent phase interference effects. Mesoscopic CDW materials and spin-dependent geometric phase effects, and their interplay, are becoming attractive opportunities for exploitation with the rapid development of modern fabrication technology. {copyright} {ital 1998} {ital The American Physical Society}

  10. A density functional theory investigation of charge mobility in titanyl-phthalocyanines and their tailored peripherally substituted complexes

    CERN Document Server

    De Lile, Jeffrey R

    2016-01-01

    Titanyl-phthalocyanines catalytic ability towards oxygen reduction is demonstrated in experimental literature. Our recent theoretical simulations revealed electronic structure origin of catalytic ability in peripherally and axially substituted triplet and singlet titanyl-phthalocyanines. However, the origin of high electron transfer ability to spontaneously reduce peroxide in chlorine substituted singlet complex and triplet state Ti(II)Pc complexes remain elusive. Thus, we performed density functional theory calculations to study Ti(IV)Pc and their tailored peripheral substituted complexes as representative compounds of titanyl-phthalocyanines for charge mobilities, reorganization energies and electronic couplings. In addition, oxo(phthalocyaninato)titanium(IV) (TiOPc) convex and concave compounds were investigated to benchmark the method. Based on the results, Reorganization energies of triplet state Ti(II)Pc and their tailored peripheral substituted complexes are compared with Ti(IV)Pc singlet complexes in ...

  11. Three-Dimensional Charge Density Wave Order in YBa2Cu3O6.67 at High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, S.; Jang, H.; Nojiri, H.; Matsuzawa, S.; Yasumura, H.; Bonn, D. A.; Liang, R.; Hardy, W.; Islam, Z.; Lee, W. -S.; Zhu, D.; Lee, J. -S.

    2015-11-20

    Charge density wave (CDW) correlations have been shown to universally exist in cuprate superconductors. However, their nature at high fields inferred from nuclear magnetic resonance is distinct from that measured by x-ray scattering at zero and low fields. Here we combine a pulsed magnet with an x-ray free electron laser to characterize the CDW in YBa2Cu3O6.67 via x-ray scattering in fields up to 28 Tesla. While the zero-field CDW order, which develops below T ~ 150 K, is essentially two-dimensional, at lower temperature and beyond 15 Tesla, another three-dimensionally ordered CDW emerges. The field-induced CDW onsets around the zero-field superconducting transition temperature, yet the incommensurate inplane ordering vector is field-independent. This implies that the two forms of CDW and hightemperature superconductivity are intimately linked.

  12. Coherent tunneling between elementary conducting layers in NbSe sub 3 conductor with wave charge density

    CERN Document Server

    Latyshev, Y I; Sinchenko, A A; Bulaevskii, L N; Monceau, P

    2002-01-01

    The peculiarities of the cross-sectional transport in the direction of the crystallographic axis alpha * in the conductor with the NbSe sub 3 wave charge density (WCD) are studied. The strong peak of dynamic conductivity is observed on the WCD of the layered structures and the NbSe sub 3 -NbSe sub 3 point contacts at low temperatures by the zero voltage shift. The identified behavior reminds in many respects the interlayer tunnel conductivity in the Bi-2212-type high-temperature layered conductors. The conductivity peak by the zero shift is explained in the model of the almost coherent interlayer tunneling of the carriers, noncondensed in the WCD

  13. Magnetic-field-tuned charge density wave in SmNiC2 and NdNiC2

    Science.gov (United States)

    Lei, Hechang; Wang, Kefeng; Petrovic, C.

    2017-02-01

    We report magnetic field tuned competition between magnetic order and charge density wave (CDW) states in SmNiC2 and NdNiC2 polycrystals. The destruction of CDW can be observed not only in SmNiC2 below ferromagnetic (FM) but also in NdNiC2 below antiferromagnetic (AFM) transition temperature. Moreover, the CDW states near magnetic transition temperatures can be tuned by the magnetic field for both compounds. Magnetic-field induced FM state in NdNiC2 is more effective in weakening the CDW than the AFM state at temperatures near Neel temperature T N but both ordering states have the same effect on CDW below T N. The interplay between magnetic and CDW states in SmNiC2 and NdNiC2 may be different, suggesting that these materials are good models to study correlations between magnetic and CDW wave order.

  14. Extended phonon collapse and the origin of the charge-density-wave in NbSe{sub 2}.

    Energy Technology Data Exchange (ETDEWEB)

    Weber, F.; Rosenkranz, S.; Castellan, J.-P.; Osborn, R.; Hott, R.; Heid, R.; Bohnen, K.-P.; Egami, T.; Said, A. H.; Reznik, D. (X-Ray Science Division); ( MSD); (Karlsruhe Inst. of Tech.); (Univ. of Tennessee); (Univ. of Colorado at Boulder)

    2011-01-01

    We report inelastic x-ray scattering measurements of the temperature dependence of phonon dispersion in the prototypical charge-density-wave (CDW) compound 2H-NbSe{sub 2}. Surprisingly, acoustic phonons soften to zero frequency and become overdamped over an extended region around the CDW wave vector. This extended phonon collapse is dramatically different from the sharp cusp in the phonon dispersion expected from Fermi surface nesting. Instead, our experiments, combined with ab initio calculations, show that it is the wave vector dependence of the electron-phonon coupling that drives the CDW formation in 2H-NbSe{sub 2} and determines its periodicity. This mechanism explains the so far enigmatic behavior of CDW in 2H-NbSe{sub 2} and may provide a new approach to other strongly correlated systems where electron-phonon coupling is important.

  15. Strong anharmonicity induces quantum melting of charge density wave in 2 H -NbSe2 under pressure

    Science.gov (United States)

    Leroux, Maxime; Errea, Ion; Le Tacon, Mathieu; Souliou, Sofia-Michaela; Garbarino, Gaston; Cario, Laurent; Bosak, Alexey; Mauri, Francesco; Calandra, Matteo; Rodière, Pierre

    2015-10-01

    The pressure and temperature dependence of the phonon dispersion of 2 H -NbSe2 is measured by inelastic x-ray scattering. A strong temperature dependent soft phonon mode, reminiscent of the charge density wave (CDW), is found to persist up to a pressure as high as 16 GPa, far above the critical pressure at which the CDW disappears at 0 K. By using ab initio calculations beyond the harmonic approximation, we obtain an accurate, quantitative description of the (P ,T ) dependence of the phonon spectrum. Our results show that the rapid destruction of the CDW under pressure is related to the zero mode vibrations—or quantum fluctuations—of the lattice renormalized by the anharmonic part of the lattice potential. The calculations also show that the low-energy longitudinal acoustic mode that drives the CDW transition barely contributes to superconductivity, explaining the insensitivity of the superconducting critical temperature to the CDW transition.

  16. Density functional studies on wurtzite piezotronic transistors: influence of different semiconductors and metals on piezoelectric charge distribution and Schottky barrier.

    Science.gov (United States)

    Liu, Wei; Zhang, Aihua; Zhang, Yan; Wang, Zhong Lin

    2016-05-20

    The mechanical-electrical coupling properties of piezoelectric semiconductors endow these materials with novel device applications in microelectromechanical systems, sensors, human-computer interfaces, etc. When an applied strain is exerted on a piezoelectric semiconductor, piezoelectric charges are generated at the surface or interface of the semiconductor, which can be utilized to control the electronic transport characteristics. This is the fundamental working mechanism of piezotronic devices, called the piezotronic effect. In the present report, a series of piezotronic transistors composed of different electrode metals and semiconductors is examined using density functional theory calculation. It is found that the influence of semiconductors on the piezotronic effect is larger than the impact of metals, and GaN and CdS are promising candidates for piezotronic and piezo-phototronic devices, respectively. The width of the piezoelectric charge distribution obtained in the present study can be used as a parameter in classical finite-element-method based simulations, which provide guidance on designing high-performance piezotronic devices.

  17. Antimicrobial polymers prepared by ring-opening metathesis polymerization: manipulating antimicrobial properties by organic counterion and charge density variation.

    Science.gov (United States)

    Lienkamp, Karen; Madkour, Ahmad E; Kumar, Kushi-Nidhi; Nüsslein, Klaus; Tew, Gregory N

    2009-11-02

    The synthesis and characterization of a series of poly(oxanorbornene)-based synthetic mimics of antimicrobial peptides (SMAMPs) is presented. In the first part, the effect of different organic counterions on the antimicrobial properties of the SMAMPs was investigated. Unexpectedly, adding hydrophobicity by complete anion exchange did not increase the SMAMPs' antimicrobial activity. It was found by dye-leakage studies that this was due to the loss of membrane activity of these polymers caused by the formation of tight ion pairs between the organic counterions and the polymer backbone. In the second part, the effect of molecular charge density on the biological properties of a SMAMP was investigated. The results suggest that, above a certain charge threshold, neither minimum inhibitory concentration (MIC90) nor hemolytic activity (HC50) is greatly affected by adding more cationic groups to the molecule. A SMAMP with an MIC90 of 4 microg mL(-1) against Staphylococcus aureus and a selectivity (=HC50/MIC90) of 650 was discovered, the most selective SMAMP to date.

  18. Pressure dependence of the optical properties of the charge-density-wave compound LaTe2

    Energy Technology Data Exchange (ETDEWEB)

    Lavagnini, M.; Sacchetti, A.; Degiorgi, L.; /Zurich, ETH; Arcangeletti, E.; Baldassarre, L.; Postorino, P.; Lupi, S.; /Rome U.; Perucchi, A.; /INFM, Trieste; Shin, K.Y.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2009-12-14

    We report the pressure dependence of the optical response of LaTe{sub 2}, which is deep in the charge-density-wave (CDW) ground state even at 300 K. The reflectivity spectrum is collected in the mid-infrared spectral range at room temperature and at pressures between 0 and 7 GPa. We extract the energy scale due to the single particle excitation across the CDW gap and the Drude weight. We establish that the gap decreases upon compressing the lattice, while the Drude weight increases. This signals a reduction in the quality of nesting upon applying pressure, therefore inducing a lesser impact of the CDW condensate on the electronic properties of LaTe{sub 2}. The consequent suppression of the CDW gap leads to a release of additional charge carriers, manifested by the shift of weight from the gap feature into the metallic component of the optical response. On the contrary, the power-law behavior, seen in the optical conductivity at energies above the gap excitation and indicating a weakly interacting limit within the Tomonaga-Luttinger liquid scenario, seems to be only moderately dependent on pressure.

  19. Density functional studies on wurtzite piezotronic transistors: influence of different semiconductors and metals on piezoelectric charge distribution and Schottky barrier

    Science.gov (United States)

    Liu, Wei; Zhang, Aihua; Zhang, Yan; Wang, Zhong Lin

    2016-05-01

    The mechanical-electrical coupling properties of piezoelectric semiconductors endow these materials with novel device applications in microelectromechanical systems, sensors, human-computer interfaces, etc. When an applied strain is exerted on a piezoelectric semiconductor, piezoelectric charges are generated at the surface or interface of the semiconductor, which can be utilized to control the electronic transport characteristics. This is the fundamental working mechanism of piezotronic devices, called the piezotronic effect. In the present report, a series of piezotronic transistors composed of different electrode metals and semiconductors is examined using density functional theory calculation. It is found that the influence of semiconductors on the piezotronic effect is larger than the impact of metals, and GaN and CdS are promising candidates for piezotronic and piezo-phototronic devices, respectively. The width of the piezoelectric charge distribution obtained in the present study can be used as a parameter in classical finite-element-method based simulations, which provide guidance on designing high-performance piezotronic devices.

  20. Spectroscopic analysis and charge transfer interaction studies of 4-benzyloxy-2-nitroaniline insecticide: A density functional theoretical approach

    Science.gov (United States)

    Arul Dhas, D.; Hubert Joe, I.; Roy, S. D. D.; Balachandran, S.

    2015-01-01

    A widespread exploration on the intra-molecular charge transfer interaction through an efficient π-conjugated path from a strong electron-donor group (amino) to a strong electron-acceptor group (nitro) has been carried out using FTIR, FT-Raman, UV-Vis, fluorescence and NMR spectra on insecticide compound 4-benzyloxy-2-nitroaniline. Density functional theory method is used to determine optimized molecular geometry, harmonic vibrational wavenumbers and intensities using 6-311G(d,p) basis set by means of Gaussian 09W program suit. A comprehensive investigation on the sp2 to sp3 hybridization and non-planarity property has been performed. Natural bond orbital analysis is used to study the existence of C-H⋯O, N-H⋯O and C-H⋯π proper and improper hydrogen bonds. The HOMO and LUMO analysis reveals the possibility of charge transfer within the molecule. A complete assignment of the experimental absorption peaks in the ultraviolet region has also been performed. Isotropic chemical shifts of 13C, 1H, 15N and 18O NMR and nuclear spin-spin coupling constants have been computed using the gauge-invariant atomic orbital method. The biological activity of substituent amino and nitro groups are evident from the hydrogen bonds through which the target amino acids are linked to the drug as evidenced from molecular docking.

  1. Constraining the density dependence of the symmetry energy using the multiplicity and average $p_T$ ratios of charged pions

    CERN Document Server

    Cozma, M D

    2016-01-01

    The charged pion multiplicity ratio in intermediate energy heavy-ion collisions, a probe of the density dependence of symmetry energy above the saturation point, has been proven in a previous study to be extremely sensitive to the strength of the isovector $\\Delta$(1232) potential in nuclear matter. As there is no current knowledge, either from theory or experiment, about the magnitude of this quantity, the extraction of constraints for the slope of the symmetry energy at saturation by using exclusively the mentioned observable is hindered at present. It is shown that, by including the ratio of average $p_T$ of charged pions $\\langle p_T^{(\\pi^+)}\\rangle/\\langle p_T^{(\\pi^-)}\\rangle$ in the list of fitted observables, the noted problem can be circumvented. A realistic description of this observable requires the accounting for the interaction of pions with the dense nuclear matter environment by the incorporation of the so called S-wave and P-wave pion optical potentials. This is performed within the framework...

  2. Surfactant enhanced volumetric sweep efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Harwell, J.H.; Scamehorn, J.F.

    1989-10-01

    Surfactant-enhanced waterflooding is a novel EOR method aimed to improve the volumetric sweep efficiencies in reservoirs. The technique depends upon the ability to induce phase changes in surfactant solutions by mixing with surfactants of opposite charge or with salts of appropriate type. One surfactant or salt solution is injected into the reservoir. It is followed later by injection of another surfactant or salt solution. The sequence of injections is arranged so that the two solutions do not mix until they are into the permeable regions well away from the well bore. When they mix at this point, by design they form a precipitate or gel-like coacervate phase, plugging this permeable region, forcing flow through less permeable regions of the reservoir, improving sweep efficiency. The selectivity of the plugging process is demonstrated by achieving permeability reductions in the high permeable regions of Berea sandstone cores. Strategies were set to obtain a better control over the plug placement and the stability of plugs. A numerical simulator has been developed to investigate the potential increases in oil production of model systems. Furthermore, the hardness tolerance of anionic surfactant solutions is shown to be enhanced by addition of monovalent electrolyte or nonionic surfactants. 34 refs., 32 figs., 8 tabs.

  3. A two-phase charge-density real-space-pairing model of high-T{sub c} superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, C.J. [Cambridge Univ. (United Kingdom). Dept. of Metallurgy and Materials Science

    1999-03-01

    It is usually assumed that high-T{sub c} superconductors have a periodic band structure and a periodic charge density, although amorphous low-T{sub c} superconductors are known. In this paper, it is suggested that the CuO{sub 2} conduction planes of cuprate superconductors consist of regions of two different charge densities which do not normally repeat periodically. It is suggested that the pairing of holes occurs in real space in cuprate superconductors. It is proposed that the hole-pairing mechanism is magnetic exchange coupling and the pairing force is strong, the pairing energy being greater than kT at room temperature. The bound hole pair is essentially a bipolaron. A real-space model is very tentatively suggested in which the CuO{sub 2} planes of YBa{sub 2}Cu{sub 3}O{sub 7} contain nanodomains of a 3 x 3 hole lattice surrounded by interfaces one unit cell wide in which the holes are paired. In the superconducting state in this model, the existing hole pairs condense and move coherently and collectively around the insulating nanodomains, like trams running around blocks of houses, with one hole on each tramline. The hole pairs move in an elegant manner with hole pairs hopping from oxygen to oxygen via adjacent copper sites. The model explains the superconducting current being in the ab plane and it also explains the very short coherence lengths. Because the pairing force is strong, the model suggests that room-temperature superconductivity might be possible in carefully designed new oxide materials. (orig.) 22 refs.

  4. A two-phase charge-density real-space-pairing model of high-Tc superconductivity.

    Science.gov (United States)

    Humphreys

    1999-03-01

    It is usually assumed that high-T(c) superconductors have a periodic band structure and a periodic charge density, although amorphous low-T(c) superconductors are known. In this paper, it is suggested that the CuO(2) conduction planes of cuprate superconductors consist of regions of two different charge densities which do not normally repeat periodically. It is suggested that the pairing of holes occurs in real space in cuprate superconductors. It is proposed that the hole-pairing mechanism is magnetic exchange coupling and the pairing force is strong, the pairing energy being greater than kT at room temperature. The bound hole pair is essentially a bipolaron. A real-space model is very tentatively suggested in which the CuO(2) planes of YBa(2)Cu(3)O(7) contain nanodomains of a 3 x 3 hole lattice surrounded by interfaces one unit cell wide in which the holes are paired. In the superconducting state in this model, the existing hole pairs condense and move coherently and collectively around the insulating nanodomains, like trams running around blocks of houses, with one hole on each tramline. The hole pairs move in an elegant manner with hole pairs hopping from oxygen to oxygen via adjacent copper sites. The model explains the superconducting current being in the ab plane and it also explains the very short coherence lengths. Because the pairing force is strong, the model suggests that room-temperature superconductivity might be possible in carefully designed new oxide materials.

  5. Measurement of atomic electric fields and charge densities from average momentum transfers using scanning transmission electron microscopy.

    Science.gov (United States)

    Müller-Caspary, Knut; Krause, Florian F; Grieb, Tim; Löffler, Stefan; Schowalter, Marco; Béché, Armand; Galioit, Vincent; Marquardt, Dennis; Zweck, Josef; Schattschneider, Peter; Verbeeck, Johan; Rosenauer, Andreas

    2016-05-12

    This study sheds light on the prerequisites, possibilities, limitations and interpretation of high-resolution differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). We draw particular attention to the well-established DPC technique based on segmented annular detectors and its relation to recent developments based on pixelated detectors. These employ the expectation value of the momentum transfer as a reliable measure of the angular deflection of the STEM beam induced by an electric field in the specimen. The influence of scattering and propagation of electrons within the specimen is initially discussed separately and then treated in terms of a two-state channeling theory. A detailed simulation study of GaN is presented as a function of specimen thickness and bonding. It is found that bonding effects are rather detectable implicitly, e.g., by characteristics of the momentum flux in areas between the atoms than by directly mapping electric fields and charge densities. For strontium titanate, experimental charge densities are compared with simulations and discussed with respect to experimental artifacts such as scan noise. Finally, we consider practical issues such as figures of merit for spatial and momentum resolution, minimum electron dose, and the mapping of larger-scale, built-in electric fields by virtue of data averaged over a crystal unit cell. We find that the latter is possible for crystals with an inversion center. Concerning the optimal detector design, this study indicates that a sampling of 5mrad per pixel is sufficient in typical applications, corresponding to approximately 10×10 available pixels.

  6. Charge density wave and excitonic magnetic polarons in CeTe sub 2

    CERN Document Server

    Kasuya, T; Takabatake, T

    2000-01-01

    Mechanisms of anomalous magnetic and transport properties in CeTe sub 2 observed recently on single-crystal samples are studied by comparing with the nonmagnetic reference material LaTe sub 2 , as well as other typical low carrier-density systems such as Ce monopnictides, doped Eu chalcogenides and Yb sub 4 As sub 3. The present system is unique on the point of low-carrier semimetal due to CDW of near perfect nesting, which is shown to be nearly independent of the spin-orbit splitting. The large residual resistivity indicates the giant molecular scattering due to excitonic states forming the distorted Wigner crystal, similar to Yb sub 4 As sub 3. At low temperatures, induced magnetic polarons cause unusual novel transport properties with a sharp peak of resistivity without any anomaly on other physical properties. This is attributed to a sharp glassy transition from an antiferromagnetic short-range ordering to the ferromagnetic ordering of the magnetic polarons within each CeTe double layer sandwiching the mo...

  7. A method for the assessment of oxide charge density and centroid in metal-oxide-semiconductor structures after uniform gate stress

    Science.gov (United States)

    Kies, R.; Egilsson, T.; Ghibaudo, G.; Pananakakis, G.

    1996-06-01

    A method for the extraction of the oxide charge density and distribution centroid based on the exploitation of the Fowler plot derivative characteristics is proposed. To this end, the modification of the tunnel transparency due to the presence of charge within the tunneling region is accounted for. Simple analytical formulas which enable the oxide charge density and centroid to be extracted from the maximum Fowler derivative and its electric field position are derived. The comparison with the DiMaria method confirms the overall consistency of the new approach. The impact of negative charge within the oxide on the apparent Fowler barrier height, which can be deduced from the slope of the Fowler plots after uniform gate stress is also analyzed. Finally, it is pointed out that this method permits the oxide trapping properties to be studied even though only one bias polarization can be utilized for the test structure.

  8. Structural and electron charge density studies of a nonlinear optical compound 4,4 di-methyl amino cyano biphenyl

    Science.gov (United States)

    Naima, Boubegra; Abdelkader, Chouaih; Mokhtaria, Drissi; Fodil, Hamzaoui

    2014-01-01

    The 4,4 dimethyl amino cyano biphenyl crystal (DMACB) is characterized by its nonlinear activity. The intra molecular charge transfer of this molecule results mainly from the electronic transmission of the electro-acceptor (cyano) and electro-donor (di-methyl-amino) groups. An accurate electron density distribution around the molecule has been calculated based on a high-resolution X-ray diffraction study. The data were collected at 123 K using graphite-monochromated Mo K α radiation to sin(β)/λ = 1.24 Å-1. The integrated intensities of 13796 reflections were measured and reduced to 6501 independent reflections with I >= 3σ(I). The crystal structure was refined using the experimental model of Hansen and Coppens (1978). The crystal structure has been validated and deposited at the Cambridge Crystallographic Data Centre with the deposition number CCDC 876507. In this article, we present the thermal motion and the structural analysis obtained from the least-square refinement based on F2 and the electron density distribution obtained from the multipolar model.

  9. Splitting of the Ti-3d bands of TiSe2 in the charge-density wave phase

    Science.gov (United States)

    Ghafari, A.; Petaccia, L.; Janowitz, C.

    2017-02-01

    Very high resolution angular resolved photoemission (ARPES) spectra on TiSe2 in two distinct polarization geometries (vertical and horizontal) at temperatures between 300 K and 22 K enabled the observation of details of bands near the Fermi level not reported so far. Calculations of the electronic band structure based on density functional theory (DFT) using B3LYP hybrid functional and MBJ potential (with and without spin-orbit coupling) were performed to obtain the orbital symmetry and dispersion. Two degenerate conduction bands (CB's) were observed at the Γ-point, a weak CB- emission at the A-point, and two non degenerate CB's (i.e. splitting of CB) at the M/L-point of the Brillouin Zone (BZ). The splitting was detected at L for both polarizations, while at M remarkably only for horizontal polarization. These results cannot be fully accounted for by current theories for the charge density wave (CDW) and point to a reduced symmetry of the electronic states, possibly due to the chiral CDW.

  10. Discriminating between Metallic and Semiconducting Single-Walled Carbon Nanotubes Using Physisorbed Adsorbates: Role of Wavelike Charge-Density Fluctuations

    Science.gov (United States)

    Gao, Wang; Chen, Yun; Jiang, Qing

    2016-12-01

    Discriminating between metallic (M ) and semiconducting (S ) single-walled carbon nanotubes (SWNTs) remains a fundamental challenge in the field of nanotechnology. We address this issue by studying the adsorption of the isotropic atoms Xe, Kr, and a highly anisotropic molecule n heptane on M - and S -SWNTs with density functional theory that includes many-body dispersion forces. We find that the distinct polarizabilities of M - and S -SWNTs exhibit significantly different physisorption properties, which are also strongly controlled by the SWNT's diameter, adsorption site, adsorbate coverage, and the adsorbate's anisotropy. These findings stem from the wavelike nature of charge-density fluctuations in SWNTs. Particularly, these results allow us to rationalize the unusual √{3 }×√{3 }R 3 00 phase of Kr atoms on small gap M -SWNTs and the double desorption peak temperatures of n heptane on M -SWNTs in experiments, and also propose the n heptane as an effective sensor for experimentally discriminating M - and S -SWNTs.

  11. Effect of pristine graphene incorporation on charge storage mechanism of three-dimensional graphene oxide: superior energy and power density retention

    Science.gov (United States)

    Singh, Kiran Pal; Bhattacharjya, Dhrubajyoti; Razmjooei, Fatemeh; Yu, Jong-Sung

    2016-08-01

    In the race of gaining higher energy density, carbon’s capacity to retain power density is generally lost due to defect incorporation and resistance increment in carbon electrode. Herein, a relationship between charge carrier density/charge movement and supercapacitance performance is established. For this purpose we have incorporated the most defect-free pristine graphene into defective/sacrificial graphene oxide. A unique co-solvent-based technique is applied to get a homogeneous suspension of single to bi-layer graphene and graphene oxide. This suspension is then transformed into a 3D composite structure of pristine graphene sheets (GSs) and defective N-doped reduced graphene oxide (N-RGO), which is the first stable and homogenous 3D composite between GS and RGO to the best of our knowledge. It is found that incorporation of pristine graphene can drastically decrease defect density and thus decrease relaxation time due to improved associations between electrons in GS and ions in electrolyte. Furthermore, N doping is implemented selectively only on RGO and such doping is shown to improve the charge carrier density of the composite, which eventually improves the energy density. After all, the novel 3D composite structure of N-RGO and GS greatly improves energy and power density even at high current density (20 A/g).

  12. A simple method of extracting the polarization charge density in the AlGaN/GaN heterostructure from current-voltage and capacitance-voltage characteristics

    Institute of Scientific and Technical Information of China (English)

    Lü Yuan-Jie; Lin Zhao-Jun; Yu Ying-Xia; Meng Ling-Guo; Cao Zhi-Fang; Luan Chong-Biao; Wang Zhan-Guo

    2012-01-01

    An Ni Schottky contact on the AlGaN/GaN heterostructure is fabricated.The flat-band voltage for the Schottky contact on the AlGaN/GaN heterostructure is obtained from the forward current-voltage characteristics.With the measured capacitance-voltage curve and the flat-band voltage,the polarization charge density in the AlGaN/GaN heterostructure is investigated,and a simple formula for calculating the polarization charge density is obtained and analyzed.With the approach described in this paper,the obtained polarization charge density agrees well with the one calculated by self-consistently solving Schrodinger's and Poisson's equations.

  13. Construction of the steady state density matrix and quasilocal charges for the spin-1/2 XXZ chain with boundary magnetic fields

    Science.gov (United States)

    Matsui, Chihiro; Prosen, Tomaž

    2017-09-01

    We construct the nonequilibrium steady state (NESS) density operator of the spin-1/2 XXZ chain with non-diagonal boundary magnetic fields coupled to boundary dissipators. The Markovian boundary dissipation is found with which the NESS density operator is expressed in terms of the product of the Lax operators by relating the dissipation parameters to the boundary parameters of the spin chain. The NESS density operator can be expressed in terms of a non-Hermitian transfer operator (NHTO) which forms a commuting family of quasilocal charges. The optimization of the Mazur bound for the high temperature Drude weight is discussed by using the quasilocal charges and the conventional local charges constructed through the Bethe ansatz.

  14. Self-Consistent Determination of Atomic Charges of Ionic Liquid through a Combination of Molecular Dynamics Simulation and Density Functional Theory.

    Science.gov (United States)

    Ishizuka, Ryosuke; Matubayasi, Nobuyuki

    2016-02-09

    A self-consistent scheme is developed to determine the atomic partial charges of ionic liquid. Molecular dynamics (MD) simulation was conducted to sample a set of ion configurations, and these configurations were subject to density functional theory (DFT) calculations to determine the partial charges. The charges were then averaged and used as inputs for the subsequent MD simulation, and MD and DFT calculations were repeated until the MD results are not altered any more. We applied this scheme to 1,3-dimethylimidazolium bis(trifluoromethylsulfonyl) imide ([C1mim][NTf2]) and investigated its structure and dynamics as a function of temperature. At convergence, the average ionic charges were ±0.84 e at 350 K due to charge transfer among ions, where e is the elementary charge, while the reduced ionic charges do not affect strongly the density of [C1mim][NTf2] and radial distribution function. Instead, major effects are found on the energetics and dynamics, with improvements of the overestimated heat of vaporization and the too slow motions of ions observed in MD simulations using commonly used force fields.

  15. Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at sNN=2.76TeV

    Science.gov (United States)

    Aamodt, K.; Abrahantes Quintana, A.; Adamová, D.; Adare, A. M.; Aggarwal, M. M.; Aglieri Rinella, G.; Agocs, A. G.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Ahmad Masoodi, A.; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaráz Aviña, E.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Anguelov, V.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arbor, N.; Arcelli, S.; Arend, A.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Asryan, A.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Äystö, J.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldini Ferroli, R.; Baldisseri, A.; Baldit, A.; Bán, J.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Bathen, B.; Batigne, G.; Batyunya, B.; Baumann, C.; Bearden, I. G.; Beck, H.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdermann, E.; Berdnikov, Y.; Betev, L.; Bhasin, A.; Bhati, A. K.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biolcati, E.; Blanc, A.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Boccioli, M.; Bock, N.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Boldizsár, L.; Bombara, M.; Bombonati, C.; Book, J.; Borel, H.; Bortolin, C.; Bose, S.; Bossú, F.; Botje, M.; Böttger, S.; Boyer, B.; Braun-Munzinger, P.; Bravina, L.; Bregant, M.; Breitner, T.; Broz, M.; Brun, R.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Cara Romeo, G.; Carena, F.; Carena, W.; Carminati, F.; Casanova Díaz, A.; Caselle, M.; Castillo Castellanos, J.; Catanescu, V.; Cavicchioli, C.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chiavassa, E.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Coccetti, F.; Coffin, J.-P.; Coli, S.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Constantin, P.; Contin, G.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Cotallo, M. E.; Crescio, E.; Crochet, P.; Cuautle, E.; Cunqueiro, L.; Erasmo, G. D.; Dainese, A.; Dalsgaard, H. H.; Danu, A.; Das, D.; Das, I.; Dash, A.; Dash, S.; de, S.; de Azevedo Moregula, A.; de Barros, G. O. V.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; de Marco, N.; de Pasquale, S.; de Remigis, R.; de Rooij, R.; Delagrange, H.; Delgado Mercado, Y.; Dellacasa, G.; Deloff, A.; Demanov, V.; Dénes, E.; Deppman, A.; di Bari, D.; di Giglio, C.; di Liberto, S.; di Mauro, A.; di Nezza, P.; Dietel, T.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domínguez, I.; Dönigus, B.; Dordic, O.; Driga, O.; Dubey, A. K.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Dutta Majumdar, M. R.; Elia, D.; Emschermann, D.; Engel, H.; Erdal, H. A.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evrard, S.; Eyyubova, G.; Fabjan, C. W.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fearick, R.; Fedunov, A.; Fehlker, D.; Fekete, V.; Felea, D.; Feofilov, G.; Fernández Téllez, A.; Ferretti, A.; Ferretti, R.; Figueredo, M. A. S.; Filchagin, S.; Fini, R.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Fragkiadakis, M.; Frankenfeld, U.; Fuchs, U.; Furano, F.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gadrat, S.; Gagliardi, M.; Gago, A.; Gallio, M.; Ganoti, P.; Garabatos, C.; Gemme, R.; Gerhard, J.; Germain, M.; Geuna, C.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Girard, M. R.; Giraudo, G.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez, R.; González-Trueba, L. H.; González-Zamora, P.; González Santos, H.; Gorbunov, S.; Gotovac, S.; Grabski, V.; Grajcarek, R.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gros, P.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerra Gutierrez, C.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Gutbrod, H.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Harris, J. W.; Hartig, M.; Hasch, D.; Hasegan, D.; Hatzifotiadou, D.; Hayrapetyan, A.; Heide, M.; Heinz, M.; Helstrup, H.; Herghelegiu, A.; Hernández, C.; Herrera Corral, G.; Herrmann, N.; Hetland, K. F.; Hicks, B.; Hille, P. T.; Hippolyte, B.; Horaguchi, T.; Hori, Y.; Hristov, P.; Hřivnáčová, I.; Huang, M.; Huber, S.; Humanic, T. J.; Hwang, D. S.; Ichou, R.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Incani, E.; Innocenti, G. M.; Innocenti, P. G.; Ippolitov, M.; Irfan, M.; Ivan, C.; Ivanov, A.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jancurová, L.; Jangal, S.; Janik, R.; Jayarathna, S. P.; Jena, S.; Jirden, L.; Jones, G. T.; Jones, P. G.; Jovanović, P.; Jung, H.; Jung, W.; Jusko, A.; Kalcher, S.; Kaliňák, P.; Kalisky, M.; Kalliokoski, T.; Kalweit, A.; Kamermans, R.; Kanaki, K.; Kang, E.; Kang, J. H.; Kaplin, V.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kazantsev, A.; Kebschull, U.; Keidel, R.; Khan, M. M.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, D. J.; Kim, D. S.; Kim, D. W.; Kim, H. N.; Kim, J. H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, S. H.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kliemant, M.; Klovning, A.; Kluge, A.; Knichel, M. L.; Koch, K.; Köhler, M. K.; Kolevatov, R.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskih, A.; Kornaś, E.; Kottachchi Kankanamge Don, C.; Kour, R.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kozlov, K.; Kral, J.; Králik, I.; Kramer, F.; Kraus, I.; Krawutschke, T.; Kretz, M.; Krivda, M.; Krumbhorn, D.; Krus, M.; Kryshen, E.; Krzewicki, M.; Kucheriaev, Y.; Kuhn, C.; Kuijer, P. G.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kushpil, V.; Kweon, M. J.; Kwon, Y.; La Rocca, P.; Ladrón de Guevara, P.; Lafage, V.; Lara, C.; Larsen, D. T.; Lazzeroni, C.; Le Bornec, Y.; Lea, R.; Lee, K. S.; Lee, S. C.; Lefèvre, F.; Lehnert, J.; Leistam, L.; Lenhardt, M.; Lenti, V.; León Monzón, I.; León Vargas, H.; Lévai, P.; Li, X.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Liu, L.; Loggins, V. R.; Loginov, V.; Lohn, S.; Lohner, D.; Loizides, C.; Lopez, X.; López Noriega, M.; López Torres, E.; Løvhøiden, G.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Luquin, L.; Luzzi, C.; Ma, K.; Ma, R.; Madagodahettige-Don, D. M.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Maire, A.; Malaev, M.; Maldonado Cervantes, I.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Mangotra, L.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Martashvili, I.; Martinengo, P.; Martínez, M. I.; Martínez Davalos, A.; Martínez García, G.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastromarco, M.; Mastroserio, A.; Matthews, Z. L.; Matyja, A.; Mayani, D.; Mazza, G.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Mendez Lorenzo, P.; Mercado Pérez, J.; Mereu, P.; Miake, Y.; Midori, J.; Milano, L.; Milosevic, J.; Mischke, A.; Miśkowiec, D.; Mitu, C.; Mlynarz, J.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Monteno, M.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moretto, S.; Morsch, A.; Muccifora, V.; Mudnic, E.; Müller, H.; Muhuri, S.; Munhoz, M. G.; Munoz, J.; Musa, L.; Musso, A.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Navach, F.; Navin, S.; Nayak, T. K.; Nazarenko, S.; Nazarov, G.; Nedosekin, A.; Nendaz, F.; Newby, J.; Nicassio, M.; Nielsen, B. S.; Nikolaev, S.; Nikolic, V.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Nilsson, M. S.; Noferini, F.; Nooren, G.; Novitzky, N.; Nyanin, A.; Nyatha, A.; Nygaard, C.; Nystrand, J.; Obayashi, H.; Ochirov, A.; Oeschler, H.; Oh, S. K.; Oleniacz, J.; Oppedisano, C.; Ortiz Velasquez, A.; Ortona, G.; Oskarsson, A.; Ostrowski, P.; Otterlund, I.; Otwinowski, J.; Øvrebekk, G.; Oyama, K.; Ozawa, K.; Pachmayer, Y.; Pachr, M.; Padilla, F.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S.; Pal, S. K.; Palaha, A.; Palmeri, A.; Pappalardo, G. S.; Park, W. J.; Paticchio, V.; Pavlinov, A.; Pawlak, T.; Peitzmann, T.; Peresunko, D.; Pérez Lara, C. E.; Perini, D.; Perrino, D.; Peryt, W.; Pesci, A.; Peskov, V.; Pestov, Y.; Peters, A. J.; Petráček, V.; Petris, M.; Petrov, P.; Petrovici, M.; Petta, C.; Piano, S.; Piccotti, A.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Pitz, N.; Piuz, F.; Piyarathna, D. B.; Platt, R.; Płoskoń, M.; Pluta, J.; Pocheptsov, T.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polák, K.; Polichtchouk, B.; Pop, A.; Pospíšil, V.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pulvirenti, A.; Punin, V.; Putiš, M.; Putschke, J.; Quercigh, E.; Qvigstad, H.; Rachevski, A.; Rademakers, A.; Rademakers, O.; Radomski, S.; Räihä, T. S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Ramírez Reyes, A.; Rammler, M.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Read, K. F.; Real, J. S.; Redlich, K.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Ricaud, H.; Riccati, L.; Ricci, R. A.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rodríguez Cahuantzi, M.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Rosinský, P.; Rosnet, P.; Rossegger, S.; Rossi, A.; Roukoutakis, F.; Rousseau, S.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Rusanov, I.; Ryabinkin, E.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahoo, R.; Sahu, P. K.; Saiz, P.; Sakai, S.; Sakata, D.; Salgado, C. A.; Samanta, T.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sano, S.; Santo, R.; Santoro, R.; Sarkamo, J.; Saturnini, P.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schreiner, S.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, P. A.; Scott, R.; Segato, G.; Senyukov, S.; Seo, J.; Serci, S.; Serradilla, E.; Sevcenco, A.; Shabratova, G.; Shahoyan, R.; Sharma, N.; Sharma, S.; Shigaki, K.; Shimomura, M.; Shtejer, K.; Sibiriak, Y.; Siciliano, M.; Sicking, E.; Siemiarczuk, T.; Silenzi, A.; Silvermyr, D.; Simonetti, G.; Singaraju, R.; Singh, R.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Smakal, R.; Smirnov, N.; Snellings, R.; Søgaard, C.; Soloviev, A.; Soltz, R.; Son, H.; Song, M.; Soos, C.; Soramel, F.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Stefanini, G.; Steinbeck, T.; Stenlund, E.; Steyn, G.; Stocco, D.; Stock, R.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A. P.; Subieta Vásquez, M. A.; Sugitate, T.; Suire, C.; Šumbera, M.; Susa, T.; Swoboda, D.; Symons, T. J. M.; Szanto de Toledo, A.; Szarka, I.; Szostak, A.; Tagridis, C.; Takahashi, J.; Tapia Takaki, J. D.; Tauro, A.; Tavlet, M.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Thomas, J. H.; Tieulent, R.; Timmins, A. R.; Tlusty, D.; Toia, A.; Torii, H.; Toscano, L.; Tosello, F.; Traczyk, T.; Truesdale, D.; Trzaska, W. H.; Tumkin, A.; Turrisi, R.; Turvey, A. J.; Tveter, T. S.; Ulery, J.; Ullaland, K.; Uras, A.; Urbán, J.; Urciuoli, G. M.; Usai, G. L.; Vacchi, A.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Kolk, N.; van Leeuwen, M.; Vande Vyvre, P.; Vannucci, L.; Vargas, A.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Venaruzzo, M.; Vercellin, E.; Vergara, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Vikhlyantsev, O.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Voloshin, K.; Voloshin, S.; Volpe, G.; von Haller, B.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Wagner, B.; Wagner, V.; Wan, R.; Wang, D.; Wang, Y.; Wang, Y.; Watanabe, K.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, A.; Wilk, G.; Williams, M. C. S.; Windelband, B.; Yang, H.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yuan, X.; Yushmanov, I.; Zabrodin, E.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zbroszczyk, H.; Zelnicek, P.; Zenin, A.; Zgura, I.; Zhalov, M.; Zhang, X.; Zhou, D.; Zhu, X.; Zichichi, A.; Zinovjev, G.; Zoccarato, Y.; Zynovyev, M.

    2011-01-01

    The centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at sNN=2.76TeV is presented. The charged-particle density normalized per participating nucleon pair increases by about a factor of 2 from peripheral (70%-80%) to central (0%-5%) collisions. The centrality dependence is found to be similar to that observed at lower collision energies. The data are compared with models based on different mechanisms for particle production in nuclear collisions.

  16. Effects of nonthermal distribution of electrons and polarity of net dust-charge number density on nonplanar dust-ion-acoustic solitary waves.

    Science.gov (United States)

    Mamun, A A; Shukla, P K

    2009-09-01

    Effects of the nonthermal distribution of electrons as well as the polarity of the net dust-charge number density on nonplanar (viz. cylindrical and spherical) dust-ion-acoustic solitary waves (DIASWs) are investigated by employing the reductive perturbation method. It is found that the basic features of the DIASWs are significantly modified by the effects of nonthermal electron distribution, polarity of net dust-charge number density, and nonplanar geometry. The implications of our results in some space and laboratory dusty plasma environments are briefly discussed.

  17. Realistic calculation of the low- and high-density liquid phase separation in a charged colloidal dispersion

    Science.gov (United States)

    Lai, S. K.; Peng, W. P.; Wang, G. F.

    2001-04-01

    A realistic statistical-mechanics model is applied to describe the repulsive interaction between charged colloids. The latter, in combination with the long-range van der Waals attraction simulated under excess salt environment, gives rise to a total intercolloidal particle potential showing a clear second potential minimum. Differing from the usual Derjaguin-Landau-Verwey-Overbeek (DLVO) model, the present model is valid at any finite concentration of colloids and is thus an appropriate model for investigating the low- and high-density liquid phase transition. Employing this two-body colloid-colloid potential and in conjunction with the Weeks-Chandler-Andersen [J. D. Weeks, D. Chandler, and H. C. Andersen, J. Chem. Phys. 54, 5237 (1971)] thermodynamic perturbation theory, we derive analytical expressions for the pressure, chemical potential, and related thermodynamic functions. These thermodynamic quantities were used to calculate the phase diagrams of charged colloidal dispersions in terms of the critical parameters: temperature, volume fraction, and electrolyte concentration parameter kD. Compared with the DLVO model, we find the areas enclosed within the spinodal decomposition and also the liquid-liquid coexistence curves broader in the present model for an excess salt condition κ=kDσ0300, the disparities between the two models reduce. The same thermodynamic perturbation theory has been employed to study also the weak reversible coagulation whose physical origin is attributed to the presence of the second potential minimum. We examine various colloidal parameters that affect the structure of the latter and deduce from our analysis the conditions of colloidal stability. In comparison with the measured flocculation data for a binary mixture of polystyrene lattices and water, we find that our calculated results are generally reasonable, thus lending great credence to the presently used model.

  18. Band gap engineering of NaTaO3 using density functional theory: a charge compensated codoping strategy.

    Science.gov (United States)

    Modak, Brindaban; Srinivasu, K; Ghosh, Swapan K

    2014-08-28

    In this theoretical study, we employ a codoping strategy to reduce the band gap of NaTaO3 aimed at improving the photocatalytic activity under visible light. The systematic study includes the effects of metal (W) and nonmetal (N) codoping on the electronic structure of NaTaO3 in comparison to the effect of individual dopants. The feasibility of the introduction of N into the NaTaO3 crystal structure is found to be enhanced in the presence of W, as indicated by the calculated formation energy. This codoping leads to formation of a charge compensated system, beneficial for the minimization of vacancy related defect formation. The electronic structure calculations have been carried out using a hybrid density functional for an accurate description of the proposed system. The introduction of W in place of Ta leads to the appearance of donor states below the conduction band, while N doping in place of oxygen introduces isolated acceptor states above the valence band. The codoping of N and W also passivates undesirable discrete midgap states. This feature is not observed in the case of (Cr, N) codoped NaTaO3 in spite of its charge compensated nature. We have also studied charge non-compensated codoping using several dopant pairs, including anion-anion and cation-anion pairs. However, this non-compensated codoping introduces localized states in between the valence band and the conduction band, and hence may not be effective in enhancing the photocatalytic properties of NaTaO3. The optical spectrum shows that the absorption curve for the (W, N)-codoped NaTaO3 is extended to the visible region due to narrowing of the band gap to 2.67 eV. Moreover, its activity for the photo decomposition of water to produce both H2 and O2 remains intact. Hence, based on the present investigation we can propose (W, N) codoped NaTaO3 as a promising photocatalyst for visible light driven water splitting.

  19. Electronic Coupling Calculations for Bridge-Mediated Charge Transfer Using Constrained Density Functional Theory (CDFT) and Effective Hamiltonian Approaches at the Density Functional Theory (DFT) and Fragment-Orbital Density Functional Tight Binding (FODFTB) Level

    Energy Technology Data Exchange (ETDEWEB)

    Gillet, Natacha; Berstis, Laura; Wu, Xiaojing; Gajdos, Fruzsina; Heck, Alexander; de la Lande, Aurelien; Blumberger, Jochen; Elstner, Marcus

    2016-10-11

    In this article, four methods to calculate charge transfer integrals in the context of bridge-mediated electron transfer are tested. These methods are based on density functional theory (DFT). We consider two perturbative Green's function effective Hamiltonian methods (first, at the DFT level of theory, using localized molecular orbitals; second, applying a tight-binding DFT approach, using fragment orbitals) and two constrained DFT implementations with either plane-wave or local basis sets. To assess the performance of the methods for through-bond (TB)-dominated or through-space (TS)-dominated transfer, different sets of molecules are considered. For through-bond electron transfer (ET), several molecules that were originally synthesized by Paddon-Row and co-workers for the deduction of electronic coupling values from photoemission and electron transmission spectroscopies, are analyzed. The tested methodologies prove to be successful in reproducing experimental data, the exponential distance decay constant and the superbridge effects arising from interference among ET pathways. For through-space ET, dedicated p-stacked systems with heterocyclopentadiene molecules were created and analyzed on the basis of electronic coupling dependence on donor-acceptor distance, structure of the bridge, and ET barrier height. The inexpensive fragment-orbital density functional tight binding (FODFTB) method gives similar results to constrained density functional theory (CDFT) and both reproduce the expected exponential decay of the coupling with donor-acceptor distances and the number of bridging units. These four approaches appear to give reliable results for both TB and TS ET and present a good alternative to expensive ab initio methodologies for large systems involving long-range charge transfers.

  20. Electronic Coupling Calculations for Bridge-Mediated Charge Transfer Using Constrained Density Functional Theory (CDFT) and Effective Hamiltonian Approaches at the Density Functional Theory (DFT) and Fragment-Orbital Density Functional Tight Binding (FODFTB) Level.

    Science.gov (United States)

    Gillet, Natacha; Berstis, Laura; Wu, Xiaojing; Gajdos, Fruzsina; Heck, Alexander; de la Lande, Aurélien; Blumberger, Jochen; Elstner, Marcus

    2016-10-11

    In this article, four methods to calculate charge transfer integrals in the context of bridge-mediated electron transfer are tested. These methods are based on density functional theory (DFT). We consider two perturbative Green's function effective Hamiltonian methods (first, at the DFT level of theory, using localized molecular orbitals; second, applying a tight-binding DFT approach, using fragment orbitals) and two constrained DFT implementations with either plane-wave or local basis sets. To assess the performance of the methods for through-bond (TB)-dominated or through-space (TS)-dominated transfer, different sets of molecules are considered. For through-bond electron transfer (ET), several molecules that were originally synthesized by Paddon-Row and co-workers for the deduction of electronic coupling values from photoemission and electron transmission spectroscopies, are analyzed. The tested methodologies prove to be successful in reproducing experimental data, the exponential distance decay constant and the superbridge effects arising from interference among ET pathways. For through-space ET, dedicated π-stacked systems with heterocyclopentadiene molecules were created and analyzed on the basis of electronic coupling dependence on donor-acceptor distance, structure of the bridge, and ET barrier height. The inexpensive fragment-orbital density functional tight binding (FODFTB) method gives similar results to constrained density functional theory (CDFT) and both reproduce the expected exponential decay of the coupling with donor-acceptor distances and the number of bridging units. These four approaches appear to give reliable results for both TB and TS ET and present a good alternative to expensive ab initio methodologies for large systems involving long-range charge transfers.

  1. Far infrared conductivity of charge density wave materials and the oxygen isotope effect in high-T sub c superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Creager, W.N.

    1991-09-01

    The far infrared reflectance and conductivity of (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I and TaS{sub 3} have been measured to determine the origin of a huge infrared resonance that dominates the charge density wave (CDW) dynamics along with the pinned acoustic phason mode in the related materials (TaSe{sub 4}){sub 2}I and K{sub 0. 3}MoO{sub 3}. The measurements cover frequencies from 3 to 700cm{sup {minus}1} and the temperature range from 15K to 300K. In the niobium-doped alloys (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I, the size and frequency of the giant infrared mode remain nearly constant as the impurity concentration x is increased. For TaS{sub 3}, the pinned acoustic phason near 0.5cm{sup {minus}1} dominates {var epsilon}({omega}) and an additional small mode lies near 9cm{sup {minus}1}. The latter mode is much smaller than the infrared mode in other CDW materials. These results rule out several models of a generic infrared mode'' in CDW excitations. They are compared in detail to the predictions of a recent theory attributing the infrared mode to a bound collective mode localized at impurity sites within the crystal. The transmittance of K{sub 0.3}MoO{sub 3} has been measured at 1.2K with a strong dc electric field applied across the crystal. Under these conditions, the charge density wave depins abruptly and carries large currents with near-zero differential resistance. For some samples, the low-frequency transmittance is enhanced slightly when the CDW depins. The magnitude of the oxygen isotope effect in the high-{Tc} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} has been determined by substitution of {sup 18}O for {sup 16}O. A series of cross-exchanges was performed on high-quality polycrystalline specimens to eliminate uncertainties due to sample heat treatments and sample inhomogeneities.

  2. Fission fragment charge and mass distributions in 239Pu(n ,f ) in the adiabatic nuclear energy density functional theory

    Science.gov (United States)

    Regnier, D.; Dubray, N.; Schunck, N.; Verrière, M.

    2016-05-01

    Background: Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data are available, together with the variety of potential applications, is an incentive to develop a fully microscopic approach to fission dynamics. Purpose: In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of 239Pu using a microscopic method based on nuclear density functional theory (DFT). Methods: Our theoretical framework is the nuclear energy density functional (EDF) method, where large-amplitude collective motion is treated adiabatically by using the time-dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). In practice, the TDGCM is implemented in two steps. First, a series of constrained EDF calculations map the configuration and potential-energy landscape of the fissioning system for a small set of collective variables (in this work, the axial quadrupole and octupole moments of the nucleus). Then, nuclear dynamics is modeled by propagating a collective wave packet on the potential-energy surface. Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line. Results: We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in two-dimensional collective spaces. Theory and experiment agree typically within two mass units for the position of the asymmetric peak. As expected, calculations are sensitive to the structure of the initial state and the prescription for the collective inertia. We emphasize that results are also sensitive to the continuity of the collective landscape near scission. Conclusions: Our analysis confirms

  3. Centrality dependence of the pseudorapidity density distribution for charged particles in Pb–Pb collisions at sNN=5.02 TeV

    Directory of Open Access Journals (Sweden)

    J. Adam

    2017-09-01

    Full Text Available We present the charged-particle pseudorapidity density in Pb–Pb collisions at sNN=5.02 TeV in centrality classes measured by ALICE. The measurement covers a wide pseudorapidity range from −3.5 to 5, which is sufficient for reliable estimates of the total number of charged particles produced in the collisions. For the most central (0–5% collisions we find 21400±1300, while for the most peripheral (80–90% we find 230±38. This corresponds to an increase of (27±4% over the results at sNN=2.76 TeV previously reported by ALICE. The energy dependence of the total number of charged particles produced in heavy-ion collisions is found to obey a modified power-law like behaviour. The charged-particle pseudorapidity density of the most central collisions is compared to model calculations — none of which fully describes the measured distribution. We also present an estimate of the rapidity density of charged particles. The width of that distribution is found to exhibit a remarkable proportionality to the beam rapidity, independent of the collision energy from the top SPS to LHC energies.

  4. Centrality dependence of the pseudorapidity density distribution for charged particles in Pb--Pb collisions at $\\sqrt{s_{\\rm NN}}=5.02$ TeV

    CERN Document Server

    Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; An, Mangmang; Andrei, Cristian; Andrews, Harry Arthur; Andronic, Anton; Anguelov, Venelin; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Anwar, Rafay; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barioglio, Luca; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Espinoza Beltran, Lucina Gabriela; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biro, Gabor; Biswas, Rathijit; Biswas, Saikat; Blair, Justin Thomas; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boldizsar, Laszlo; Bombara, Marek; Bonora, Matthias; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Botta, Elena; Bourjau, Christian; Braun-munzinger, Peter; Bregant, Marco; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buhler, Paul; Iga Buitron, Sergio Arturo; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Bashir Butt, Jamila; Buxton, Jesse Thomas; Cabala, Jan; Caffarri, Davide; Caines, Helen Louise; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Capon, Aaron Allan; Carena, Francesco; Carena, Wisla; Carnesecchi, Francesca; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Ceballos Sanchez, Cesar; Cerello, Piergiorgio; Cerkala, Jakub; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chauvin, Alex; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Cho, Soyeon; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crkovska, Jana; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danisch, Meike Charlotte; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Conti, Camila; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Derradi De Souza, Rafael; Franz Degenhardt, Hermann; Deisting, Alexander; Deloff, Andrzej; Deplano, Caterina; Dhankher, Preeti; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Di Ruzza, Benedetto; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Drozhzhova, Tatiana; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Duggal, Ashpreet Kaur; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Endress, Eric; Engel, Heiko; Epple, Eliane; Erazmus, Barbara Ewa; Erhardt, Filip; Espagnon, Bruno; Esumi, Shinichi; Eulisse, Giulio; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Feuillard, Victor Jose Gaston; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Francisco, Audrey; Frankenfeld, Ulrich Michael; Fronze, Gabriele Gaetano; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gajdosova, Katarina; Gallio, Mauro; Duarte Galvan, Carlos; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-solis, Edmundo Javier; Garg, Kunal; Garg, Prakhar; Gargiulo, Corrado; Gasik, Piotr Jan; Gauger, Erin Frances; De Leone Gay, Maria Beatriz; Germain, Marie; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-dziadus, Ewa; Glassel, Peter; Gomez Coral, Diego Mauricio; Gomez Ramirez, Andres; Sanchez Gonzalez, Andres; Gonzalez, Victor; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Graham, Katie Leanne; Greiner, Leo Clifford; Grelli, Alessandro; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grion, Nevio; Gronefeld, Julius Maximilian; Grosa, Fabrizio; Grosse-oetringhaus, Jan Fiete; Grosso, Raffaele; Gruber, Lukas; Grull, Frederik Rolf; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Bautista Guzman, Irais; Haake, Rudiger; Hadjidakis, Cynthia Marie; Hamagaki, Hideki; Hamar, Gergoe; Hamon, Julien Charles; Harris, John William; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Hellbar, Ernst; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Florian; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hillemanns, Hartmut; Hippolyte, Boris; Hladky, Jan; Horak, David; Hosokawa, Ritsuya; Hristov, Peter Zahariev; Hughes, Charles; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Inaba, Motoi; Ippolitov, Mikhail; Irfan, Muhammad; Isakov, Vladimir; Islam, Md Samsul; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacak, Barbara; Jacazio, Nicolo; Jacobs, Peter Martin; Jadhav, Manoj Bhanudas; Jadlovska, Slavka; Jadlovsky, Jan; Jahnke, Cristiane; Jakubowska, Monika Joanna; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jercic, Marko; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karayan, Lilit; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Khatun, Anisa; Khuntia, Arvind; Kielbowicz, Miroslaw Marek; Kileng, Bjarte; Kim, Do Won; Kim, Dong Jo; Kim, Daehyeok; Kim, Hyeonjoong; Kim, Jinsook; Kim, Jiyoung; Kim, Minjung; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-boesing, Christian; Klewin, Sebastian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kopcik, Michal; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Koyithatta Meethaleveedu, Greeshma; Kralik, Ivan; Kravcakova, Adela; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kumar, Ajay; Kumar, Jitendra; Kumar, Lokesh; Kumar, Shyam; Kundu, Sourav; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lapidus, Kirill; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lavicka, Roman; Lazaridis, Lazaros; Lea, Ramona; Leardini, Lucia; Lee, Seongjoo; Lehas, Fatiha; Lehner, Sebastian; Lehrbach, Johannes; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Litichevskyi, Vladyslav; Ljunggren, Hans Martin; Llope, William; Lodato, Davide Francesco; Lonne, Per-ivar; Loginov, Vitaly; Loizides, Constantinos; Loncar, Petra; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Lupi, Matteo; Lutz, Tyler Harrison; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martinengo, Paolo; Lucio Martinez, Jose Antonio; Martinez Hernandez, Mario Ivan; Martinez-garcia, Gines; Martinez Pedreira, Miguel; Mas, Alexis Jean-michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Mastroserio, Annalisa; Mathis, Andreas Michael; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzilli, Marianna; Mazzoni, Alessandra Maria; Meddi, Franco; Melikyan, Yuri; Menchaca-rocha, Arturo Alejandro; Meninno, Elisa; Mercado-perez, Jorge; Meres, Michal; Mhlanga, Sibaliso; Miake, Yasuo; Mieskolainen, Matti Mikael; Mihaylov, Dimitar; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Mishra, Tribeni; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Montes Prado, Esther; Moreira De Godoy, Denise Aparecida; Perez Moreno, Luis Alberto; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Munning, Konstantin; Munzer, Robert Helmut; Murakami, Hikari; Murray, Sean; Musa, Luciano; Musinsky, Jan; Myers, Corey James; Naik, Bharati; Nair, Rahul; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; 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    2016-01-01

    We present the charged-particle pseudorapidity density in Pb--Pb collisions at $\\sqrt{s_{_{\\mathrm{NN}}}}=5.02\\,\\mathrm{Te\\kern-.25exV}$ in centrality classes measured by ALICE. The measurement covers a wide pseudorapidity range from $-3.5$ to $5$, which is sufficient for reliable estimates of the total number of charged particles produced in the collisions. For the most central collisions we find $21\\,400\\pm 1\\,300$ while for the most peripheral we find $230\\pm 38$. This corresponds to an increase of $(27\\pm4)\\%$ over the results at $\\sqrt{s_{_{\\mathrm{NN}}}}=2.76\\,\\mathrm{Te\\kern-.25exV}$ previously reported by ALICE. The energy dependence of the total number of charged particles produced in heavy-ion collisions is found to obey a modified power-law like behaviour. The charged-particle pseudorapidity density of the most central collisions is compared to model calculations --- none of which fully describes the measured distribution. We also present an estimate of the rapidity density of charged particles. Th...

  5. Charge density wave and superconductivity in 2H- and 4H-NbSe2: A revisit

    Indian Academy of Sciences (India)

    I Naik; A K Rastogi

    2011-06-01

    Good-quality hexagonal NbSe2 single crystals were prepared. In 2H-NbSe2, superconducting and charge density wave (CDW) transitions were found at = 7.4 K and = 35 K respectively as reported previously. We have noticed that these two transitions are changed to = 42 K and = 6.5 K, in 4H-NbSe2. Thermopower has shown clear anomaly at CDW transitions. The anisotropic upper critical field was calculated as ∼ 3 and 6.3 for 2H- and 4H-single crystals around = 0.81, where = /, from resistivity and explained in terms of coherence length. From the relation, $H_{c2}() = H_{c2}(0)[1 − ^2]$, $H^l_{c2}(0)$ was calculated as ∼ 8.15 T and 16.98 T at = 0.84 in 2H-NbSe2 and 4H-NbSe2 respectively. However, $H^_{c2}(0) = 2.68$ T for both single crystals.

  6. Experimental Charge Density Study of Trichromium Linear Metal String Complex – Cr3(dpa)4Cl2

    DEFF Research Database (Denmark)

    Wu, Lai-Chin; Cheng, Ming-Chuan; Thomsen, Maja Krüger

    An experimental and theoretical charge density study, based on Bader’s Quantum Theory: Atoms in Molecule (QTAIM), on a trichromium metal string complex, Cr3(dpa)4Cl2(C2H5OC2H5)x(CH2Cl2)1-x (1, dpa- = bis(2-pyridyl)amido)) is performed. The structure and multipole model of 1 are performed by using...... experimental X-ray diffraction data which are collected at both 100 K using conventional X-ray source (DS1) and 15 K using synchrotron source (DS2). The three chromium metal string is bridged by four dpa- ligands. These tri-chromium metal ions are bonded to each other and terminated by two Cl- ions on the both...... ends, forming a [Cl(1)Cr(1)Cr(2)Cr(3)Cl(2)] linear string. Each Cr atoms are coordinated by four N atoms of each dpa- ligand. This metal string is slightly unsymmetrical at both data sets. The bond distance, from DS1 (DS2), of Cr(1)Cr(2), 2.3480(2) (2.3669(1)) Å, is 0.03 (0.003) Å shorter than Cr...

  7. Effect of charge density in chain extension reactions involving complexes of 4, 4'-diaminodiphenylmethane and various alkali metal salts

    Science.gov (United States)

    Deshmukh, Subrajeet; Carrasquillo, Katherine; Tsai, Fang Chang; Wu, Lina; Hsu, Shaw Ling; University of Massachusetts Amherst Team

    Controlling the reaction of methylene diphenyl diisocyanate (MDI)-terminated polyester prepolymer and 4, 4'-diaminodiphenylmethane (MDA) is extremely important in many large scale applications. The ion-diamine complex has the advantage of blocking the instantaneous reaction between the diamine and isocyanate from taking place until it is released at elevated temperatures. We synthesized complexes of MDA with various alkali metal salts. These complexes create a barrier between the diamine and isocyanate thus preventing the premature reaction. We compared the complexes in terms of their dissociation and the subsequent curing with the prepolymer. Charge density had a tremendous effect. DSC showed that Na complexes dissociated at a lower temperature and needed less energy to dissociate than the Li complexes. The effect of change in cation on complex dissociation was more pronounced compared to the change in anion. Also, the ionic liquid introduced greatly altered the dissociation behavior. Temperature and time resolved IR spectroscopy was used to monitor the urea and NH band. By DSC and IR, we showed that NaCl complex is best suited for the curing of prepolymer with regards to curing temperature and energy.

  8. EFFECT OF RADIATION ON HIGH-CHARGE-DENSITY POLYDIALLY-DIMETHYL AMMONIUM CHLORIDE IN DILUTE AQUEOUS SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Ya-long Zhang; Min Yi; Jing Ren; Hong-fei Ha

    2003-01-01

    The effect of radiation on high-charge-density cationic polymer, polydiallyl-dimethyl ammonium chloride (polyDADMAC), in dilute aqueous solution was investigated. The irradiated samples were characterized in terms of reduced viscosity and electric conductivity. The crosslinking reaction of polyDADMAC chains occurs preferentially in the irradiated samples at a concentration of polyDADMAC higher than 1.3 g/100 mL that was induced indirectly by the OH radicals, one of the radiolysis products of water. In more dilute samples (less than 0.8 g/100 mL) the chain scission of macro radicals appears to be the main reaction. N2O atmosphere enhances the erosslinking due to the extra OH radicals produced by reaction between N2O and eaq, another radiolysis products of water. Methanol and some mineral salts such as KC1, KBr inhibit the crosslinking to a certain extent. The mechanism of sensitization and inhibition is discussed in detail.

  9. Emergence of coherence in the charge-density wave state of 2H-NbSe2

    Science.gov (United States)

    Chatterjee, U.; Zhao, J.; Iavarone, M.; Di Capua, R.; Castellan, J. P.; Karapetrov, G.; Malliakas, C. D.; Kanatzidis, M. G.; Claus, H.; Ruff, J. P. C.; Weber, F.; van Wezel, J.; Campuzano, J. C.; Osborn, R.; Randeria, M.; Trivedi, N.; Norman, M. R.; Rosenkranz, S.

    2015-01-01

    A charge-density wave (CDW) state has a broken symmetry described by a complex order parameter with an amplitude and a phase. The conventional view, based on clean, weak-coupling systems, is that a finite amplitude and long-range phase coherence set in simultaneously at the CDW transition temperature Tcdw. Here we investigate, using photoemission, X-ray scattering and scanning tunnelling microscopy, the canonical CDW compound 2H-NbSe2 intercalated with Mn and Co, and show that the conventional view is untenable. We find that, either at high temperature or at large intercalation, CDW order becomes short-ranged with a well-defined amplitude, which has impacts on the electronic dispersion, giving rise to an energy gap. The phase transition at Tcdw marks the onset of long-range order with global phase coherence, leading to sharp electronic excitations. Our observations emphasize the importance of phase fluctuations in strongly coupled CDW systems and provide insights into the significance of phase incoherence in ‘pseudogap’ states. PMID:25687135

  10. Nanoscale femtosecond imaging of transient hot solid density plasmas with elemental and charge state sensitivity using resonant coherent diffraction

    Science.gov (United States)

    Kluge, T.; Bussmann, M.; Chung, H.-K.; Gutt, C.; Huang, L. G.; Zacharias, M.; Schramm, U.; Cowan, T. E.

    2016-03-01

    Here, we propose to exploit the low energy bandwidth, small wavelength, and penetration power of ultrashort pulses from XFELs for resonant Small Angle Scattering (SAXS) on plasma structures in laser excited plasmas. Small angle scattering allows to detect nanoscale density fluctuations in forward scattering direction. Typically, the SAXS signal from laser excited plasmas is expected to be dominated by the free electron distribution. We propose that the ionic scattering signal becomes visible when the X-ray energy is in resonance with an electron transition between two bound states (resonant coherent X-ray diffraction). In this case, the scattering cross-section dramatically increases so that the signal of X-ray scattering from ions silhouettes against the free electron scattering background which allows to measure the opacity and derived quantities with high spatial and temporal resolution, being fundamentally limited only by the X-ray wavelength and timing. Deriving quantities such as ion spatial distribution, charge state distribution, and plasma temperature with such high spatial and temporal resolution will make a vast number of processes in shortpulse laser-solid interaction accessible for direct experimental observation, e.g., hole-boring and shock propagation, filamentation and instability dynamics, electron transport, heating, and ultrafast ionization dynamics.

  11. Spectral properties of actinide materials: Charge density self-consistent LDA+Hubbard I method in FP-LAPW basis

    Energy Technology Data Exchange (ETDEWEB)

    Kolorenc, Jindrich [Institute of Physics ASCR, Prague (Czech Republic); University of Hamburg, Hamburg (Germany); Shick, Alexander B. [Institute of Physics ASCR, Prague (Czech Republic); Havela, Ladislav [Charles University, Prague (Czech Republic); Lichtenstein, Alexander I. [University of Hamburg, Hamburg (Germany)

    2010-07-01

    We provide a numerically efficient procedure to perform LDA+Hubbard I calculations including self-consistency over the charge density in the FP-LAPW basis. The method is applied to Pu, Am, and PuAm and PuCe alloys. Our results for valence photoemission spectra (PES) agree with experimental data and with previous LDA+DMFT calculations. Analysis of the J=5/2 and J=7/2 contributions to the f-occupation supports the intermediate-coupling picture of f-states in heavy actinides. The electronic specific heat coefficient is calculated for PuAm and PuCe alloys in reasonable agreement with recent experiments. We show that Pu atoms keep their mixed-valence character in these alloys. Next, we study electronic and spectral properties of Pu-based superconductor PuCoGa{sub 5} and obtain good agreement with experimental PES. Finally, we analyze surface effects. In Pu monolayer, we find substantial modification of PES due to 5f-electron localization consistent with experimental observations.

  12. Halogen bonding in fluorine: experimental charge density study on intermolecular F···F and F···S donor-acceptor contacts.

    Science.gov (United States)

    Pavan, Mysore S; Durga Prasad, Karothu; Row, T N Guru

    2013-09-04

    The enigmatic type II C-F···F-C and C-F···S-C interactions in pentafluorophenyl 2,2'-bithiazole are shown to be realistic "σ-hole" interactions based on high resolution X-ray charge density analysis.

  13. C-reactive protein and annexin A5 bind to distinct sites of negatively charged phospholipids present in oxidized low-density lipoprotein.

    NARCIS (Netherlands)

    Tits, L.J.H. van; Graaf, J. de; Toenhake, H.; Heerde, W.L. van; Stalenhoef, A.F.H.

    2005-01-01

    OBJECTIVE: To investigate binding of C-reactive protein (CRP) and annexin A5, 2 proteins with high affinity for negatively charged phospholipids, to oxidized low-density lipoprotein (LDL) and the consequences of these interactions for subsequent binding of oxidized LDL to monocyte/macrophage-like

  14. Charge density mismatch synthesis of MEI- and BPH-type zeolites in the TEA(+)-TMA(+)-Li(+)-Sr(2+) mixed-structure-directing agent system.

    Science.gov (United States)

    Park, Min Bum; Ahn, Sang Hyun; Ahn, Nak Ho; Hong, Suk Bong

    2015-02-28

    Nanocrystalline MEI- and BPH-type zeolites, denoted as PST-11 and PST-12, respectively, have been synthesized using both tetraethylammonium and tetramethylammonium ions, the two simplest alkylammonium species, in the presence of Li(+) and Sr(2+). PST-12 formation is the first example of a combination of forced and multiple cooperative structure-directions in the charge density mismatch synthesis of zeolites.

  15. Effect of doping- and field-induced charge carrier density on the electron transport in nanocrystalline ZnO.

    Science.gov (United States)

    Hammer, Maria S; Rauh, Daniel; Lorrmann, Volker; Deibel, Carsten; Dyakonov, Vladimir

    2008-12-03

    The charge transport properties of thin films of sol-gel processed undoped and Al-doped zinc oxide nanoparticles with variable doping level between 0.8 and 10 at.% were investigated. The x-ray diffraction studies revealed a decrease of the average crystallite sizes in highly doped samples. We provide estimates of the conductivity and the resulting charge carrier densities with respect to the doping level. The increase of charge carrier density due to extrinsic doping was compared to the accumulation of charge carriers in field effect transistor structures. This allowed us to assess the scattering effects due to extrinsic doping on the electron mobility. The latter decreases from 4.6 × 10(-3) to 4.5 × 10(-4) cm(2) V(-1) s(-1) with increasing doping density. In contrast, the accumulation leads to an increasing mobility up to 1.5 × 10(-2) cm(2) V(-1) s(-1). The potential barrier heights related to grain boundaries between the crystallites were derived from temperature dependent mobility measurements. The extrinsic doping initially leads to a grain boundary barrier height lowering, followed by an increase due to doping-induced structural defects. We conclude that the conductivity of sol-gel processed nanocrystalline ZnO:Al is governed by an interplay of the enhanced charge carrier density and the doping-induced charge carrier scattering effects, achieving a maximum at 0.8 at.% in our case.

  16. Origin of Charge Density at LaAlO3 on SrTiO3 Heterointerfaces: Possibility of Intrinsic Doping

    Science.gov (United States)

    Siemons, Wolter; Koster, Gertjan; Yamamoto, Hideki; Harrison, Walter A.; Lucovsky, Gerald; Geballe, Theodore H.; Blank, Dave H. A.; Beasley, Malcolm R.

    2007-05-01

    As discovered by Ohtomo and Hwang, a large sheet charge density with high mobility exists at the interface between SrTiO3 and LaAlO3. Based on transport, spectroscopic, and oxygen-annealing experiments, we conclude that extrinsic defects in the form of oxygen vacancies introduced by the pulsed laser deposition process used by all researchers to date to make these samples is the source of the large carrier densities. Annealing experiments show a limiting carrier density. We also present a model that explains the high mobility based on carrier redistribution due to an increased dielectric constant.

  17. Extraction of high charge density of states in electrolyte-gated polymer thin-film transistor with temperature-dependent measurements

    Science.gov (United States)

    Lee, Jiyoul

    2016-05-01

    Using temperature-dependent charge transport measurements, we investigated spectral density of states (DOS) in the bandgap of polythiophene thin-films under high carrier densities (Meyer-Neldel rule. The spectral DOS extracted from the electrolyte-gated polymer film lie in the range of 8.0 × 1019 cm-3 eV-1-8.0 × 1021 cm-3 eV-1, which are at least two orders of magnitude larger than the DOS extracted from the same polymer film at relatively low induced carrier densities by general oxide dielectrics.

  18. Charge density studies of 3 d metal (Ni/Cu) complexes with a non-innocent ligand

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Yu-Chun; Sheu, Chou-Fu; Lee, Gene-Hsiang; Chen, Yu-Sheng; Wang, Yu (NTU); (UC)

    2017-07-25

    High-resolution X-ray diffraction experiments and atom-specific X-ray absorption experiments are applied to investigate a series of square planar complexes with the non-innocent ligand of maleonitriledithiolate (mnt), [S2C2(CN)2]z-, containingM—S bonds. Four complexes of (PyH)z[M(mnt)2]z-, whereM= Ni or Cu,z= 2 or 1 and PyH+= C5NH6+, were studied in order to clarify whether such one-electron oxidation–reduction, [M(mnt)2]2-/[M(mnt)2]1-, is taking place at the metal or the ligand site. Combining the techniques of metalK-,L-edge and SK-edge X-ray absorption spectroscopy with high-resolution X-ray charge density studies, it is unambiguously demonstrated that the electron redox reaction is ligand based and metal based for Ni and Cu pairs, respectively. The bonding characters in terms of topological properties associated with the bond critical points are compared between the oxidized form [ML]-and the reduced form [ML]2-. In the case of Ni complexes, the formal oxidation state of Ni remains as Ni2+and each mnt ligand carries a 2- charge in [Ni(mnt)2]2-, but only one of the ligands is formally oxidized in [Ni(mnt)2]1-. In contrast, in the case of Cu complexes, the mnt remains as 2- in both complexes, but the formal oxidation states of the metal are Cu2+and Cu3+. Bond characterizations andd-orbital populations will be presented. The complementary results of XAS, XRD and DFT calculations will be discussed. The conclusion on the redox reactions in these

  19. Volumetric composition in composites and historical data

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2013-01-01

    guidance to the optimal combination of fibre content, matrix content and porosity content, in order to achieve the best obtainable properties. Several composite materials systems have been shown to be handleable with this model. An extensive series of experimental data for the system of cellulose fibres...... and polymer (resin) was produced in 1942 – 1944, and these data have been (re-)analysed by the volumetric composition model, and the property values for density, stiffness and strength have been evaluated. Good agreement has been obtained and some further observations have been extracted from the analysis....

  20. Magnetic volumetric hologram memory with magnetic garnet.

    Science.gov (United States)

    Nakamura, Yuichi; Takagi, Hiroyuki; Lim, Pang Boey; Inoue, Mitsuteru

    2014-06-30

    Holographic memory is a promising next-generation optical memory that has a higher recording density and a higher transfer rate than other types of memory. In holographic memory, magnetic garnet films can serve as rewritable holographic memory media by use of magneto-optical effect. We have now demonstrated that a magnetic hologram can be recorded volumetrically in a ferromagnetic garnet film and that the signal image can be reconstructed from it for the first time. In addition, multiplicity of the magnetic hologram was also confirmed; the image could be reconstructed from a spot overlapped by other spots.

  1. Field-induced charge-density-wave transitions in the organic metal α-(BEDT-TTF)2KHg(SCN)4 under pressure

    Science.gov (United States)

    Andres, D.; Kartsovnik, M. V.; Biberacher, W.; Neumaier, K.; Sheikin, I.; Müller, H.; Kushch, N. D.

    2011-10-01

    Successive magnetic-field-induced charge-density-wave transitions in the layered molecular conductor α-(BEDT-TTF)2KHg(SCN)4 are studied in a hydrostatic pressure regime in which the zero field charge-density- wave (CDW) state is completely suppressed. It is shown that the orbital effect of the magnetic field restores the density wave, while orbital quantization induces transitions between different CDW states as the field strength is varied. The latter show up as distinct anomalies in the magnetoresistance as a function of field. The interplay between the orbital and Pauli paramagnetic effects, which act, respectively, to enhance and to suppress the CDW instability, is particularly manifest in the angular dependence of the field-induced anomalies.

  2. Modulated two-dimensional charge-carrier density in LaTiO3-layer-doped LaAlO3/SrTiO3 heterostructure.

    Science.gov (United States)

    Nazir, Safdar; Bernal, Camille; Yang, Kesong

    2015-03-11

    The highly mobile two-dimensional electron gas (2DEG) formed at the polar/nonpolar LaAlO3/SrTiO3 (LAO/STO) heterostructure (HS) is a matter of great interest because of its potential applications in nanoscale solid-state devices. To realize practical implementation of the 2DEG in device design, desired physical properties such as tuned charge carrier density and mobility are necessary. In this regard, polar perovskite-based transition metal oxides can act as doping layers at the interface and are expected to tune the electronic properties of 2DEG of STO-based HS systems dramatically. Herein, we investigated the doping effects of LaTiO3(LTO) layers on the electronic properties of 2DEG at n-type (LaO)(+1)/(TiO2)(0) interface in the LAO/STO HS using spin-polarized density functional theory calculations. Our results indicate an enhancement of orbital occupation near the Fermi energy, which increases with respect to the number of LTO unit cells, resulting in a higher charge carrier density of 2DEG than that of undoped system. The enhanced charge carrier density is attributed to an extra electron introduced by the Ti 3d(1) orbitals from the LTO dopant unit cells. This conclusion is consistent with the recent experimental findings (Appl. Phys. Lett. 2013, 102, 091601). Detailed charge density and partial density of states analysis suggests that the 2DEG in the LTO-doped HS systems primarily comes from partially occupied dyz and dxz orbitals.

  3. Controlling the interface charge density in GaN-based metal-oxide-semiconductor heterostructures by plasma oxidation of metal layers

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Herwig, E-mail: herwig.hahn@rwth-aachen.de; Kalisch, Holger; Vescan, Andrei [GaN Device Technology, RWTH Aachen University, 52074 Aachen (Germany); JARA-Fundamentals of Future Information Technologies, 52425 Jülich (Germany); Pécz, Béla [MTA EK MFA, Konkoly Thege Street 29-33, 1121 Budapest (Hungary); Kovács, András [JARA-Fundamentals of Future Information Technologies, 52425 Jülich (Germany); Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Forschungszentrum Jülich, Peter Grünberg Institut (PGI-5), 52425 Jülich (Germany); Heuken, Michael [GaN Device Technology, RWTH Aachen University, 52074 Aachen (Germany); AIXTRON SE, 52134 Herzogenrath (Germany)

    2015-06-07

    In recent years, investigating and engineering the oxide-semiconductor interface in GaN-based devices has come into focus. This has been driven by a large effort to increase the gate robustness and to obtain enhancement mode transistors. Since it has been shown that deep interface states act as fixed interface charge in the typical transistor operating regime, it appears desirable to intentionally incorporate negative interface charge, and thus, to allow for a positive shift in threshold voltage of transistors to realise enhancement mode behaviour. A rather new approach to obtain such negative charge is the plasma-oxidation of thin metal layers. In this study, we present transmission electron microscopy and energy dispersive X-ray spectroscopy analysis as well as electrical data for Al-, Ti-, and Zr-based thin oxide films on a GaN-based heterostructure. It is shown that the plasma-oxidised layers have a polycrystalline morphology. An interfacial amorphous oxide layer is only detectable in the case of Zr. In addition, all films exhibit net negative charge with varying densities. The Zr layer is providing a negative interface charge density of more than 1 × 10{sup 13 }cm{sup –2} allowing to considerably shift the threshold voltage to more positive values.

  4. Suppression and inducement of the charge-density-wave state in Cr x TiSe2.

    Science.gov (United States)

    Selezneva, N V; Sherokalova, E M; Pleshchev, V G; Kazantsev, V A; Baranov, N V

    2016-08-10

    The x-ray diffraction, electrical resistivity and thermal expansion measurements have been employed to study how the intercalation of Cr atoms into TiSe2 matrix affects the crystal structure, formation of the charge density wave (CDW) and electrical properties. The intercalation of a small amount of Cr atoms (up to x ~ 0.03) is observed to suppress the CDW formation. The electrical resistivity of Cr x TiSe2 compounds with the Cr concentrations 0.03  ⩽  x  ⩽  0.20 shows a metallic-type behavior; while in the concentration range 0.25  ⩽  x  ⩽  0.5, the resistivity shows an anomalous behavior indicating the reappearance of the transition to a CDW-like state; further growth of the Cr content up to x  =  0.6 again leads to the metallic-type resistivity. For the compound Cr0.25TiSe2, the phase transition below 160 K together with abnormal change in the electrical resistivity is found to be accompanied by anomalies in the lattice parameters and thermal expansion behavior; this transition is classified as first-order type. It has been found that despite the intercalation of Cr atoms some Ti-Se bonds in the Se-Ti-Se tri-layers of Cr x TiSe2 with x  ⩽  0.5 have nearly the same lengths as in the host lattice TiSe2, which apparently allows the transition to be returned to the CDW-like state.

  5. Mismatch of dielectric constants at the interface of nanometer metal-oxide-semiconductor devices with high- gate dielectric impacts on the inversion charge density

    Indian Academy of Sciences (India)

    Ling-Feng Mao

    2011-04-01

    The comparison of the inversion electron density between a nanometer metal-oxidesemiconductor (MOS) device with high- gate dielectric and a SiO2 MOS device with the same equivalent oxide thickness has been discussed. A fully self-consistent solution of the coupled Schrödinger–Poisson equations demonstrates that a larger dielectric-constant mismatch between the gate dielectric and silicon substrate can reduce electron density in the channel of a MOS device under inversion bias. Such a reduction in inversion electron density of the channel will increase with increase in gate voltage. A reduction in the charge density implies a reduction in the inversion electron density in the channel of a MOS device. It also implies that a larger dielectric constant of the gate dielectric might result in a reduction in the source–drain current and the gate leakage current.

  6. Quantitative Techniques in Volumetric Analysis

    Science.gov (United States)

    Zimmerman, John; Jacobsen, Jerrold J.

    1996-12-01

    Quantitative Techniques in Volumetric Analysis is a visual library of techniques used in making volumetric measurements. This 40-minute VHS videotape is designed as a resource for introducing students to proper volumetric methods and procedures. The entire tape, or relevant segments of the tape, can also be used to review procedures used in subsequent experiments that rely on the traditional art of quantitative analysis laboratory practice. The techniques included are: Quantitative transfer of a solid with a weighing spoon Quantitative transfer of a solid with a finger held weighing bottle Quantitative transfer of a solid with a paper strap held bottle Quantitative transfer of a solid with a spatula Examples of common quantitative weighing errors Quantitative transfer of a solid from dish to beaker to volumetric flask Quantitative transfer of a solid from dish to volumetric flask Volumetric transfer pipet A complete acid-base titration Hand technique variations The conventional view of contemporary quantitative chemical measurement tends to focus on instrumental systems, computers, and robotics. In this view, the analyst is relegated to placing standards and samples on a tray. A robotic arm delivers a sample to the analysis center, while a computer controls the analysis conditions and records the results. In spite of this, it is rare to find an analysis process that does not rely on some aspect of more traditional quantitative analysis techniques, such as careful dilution to the mark of a volumetric flask. Figure 2. Transfer of a solid with a spatula. Clearly, errors in a classical step will affect the quality of the final analysis. Because of this, it is still important for students to master the key elements of the traditional art of quantitative chemical analysis laboratory practice. Some aspects of chemical analysis, like careful rinsing to insure quantitative transfer, are often an automated part of an instrumental process that must be understood by the

  7. Density functional study of electronic, charge density, and chemical bonding properties of 9-methyl-3-Thiophen-2-YI-Thieno [3,2-e] [1, 2, 4] Thriazolo [4,3-c] pyrimidine-8-Carboxylic acid ethyl ester crystals

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A.H., E-mail: maalidph@yahoo.co.uk [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Kamarudin, H. [Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Alahmed, Z.A. [Department of Physics and Astronomy, King Saud University, Riyadh 11451 (Saudi Arabia); Auluck, S. [CSIR-National Physical Laboratory, Dr. K S Krishnan Marg, New Delhi 110012 (India); Chyský, Jan [Department of Instrumentation and Control Engineering, Faculty of Mechanical Engineering, CTU in Prague, Technicka 4, 166 07 Prague 6 (Czech Republic)

    2014-06-01

    A comprehensive theoretical density functional investigation of the electronic crystal structure, chemical bonding, and the electron charge densities of 9-Methyl-3-Thiophen-2-YI-Thieno [3, 2-e] [1, 2, 4] Thriazolo [4,3-c] Pyrimidine-8-Carboxylic Acid Ethyl Ester (C{sub 15}H{sub 12}N{sub 4}O{sub 2}S{sub 2}) is performed. The density of states at Fermi level equal to 5.50 (3.45) states/Ry cell, and the calculated bare electronic specific heat coefficient is found to be 0.95 (0.59) mJ/mole-K{sup 2} for the local density approximation (Engel–Vosko generalized gradient approximation). The electronic charge density space distribution contours in (1 0 0) and (1 1 0) planes were calculated. We find that there are two independent molecules (A and B) in the asymmetric unit exhibit intramolecular C–H…O, C–H…N interactions. This intramolecular interaction is different in molecules A and B, where A molecule show C–H…O interaction while B molecule exhibit C–H…N interaction. We should emphasis that there is π–π interaction between the pyrimidine rings of the two neighbors B molecules gives extra strengths and stabilizations to the superamolecular structure. The calculated distance between the two neighbors pyrimidine rings found to be 3.345 Å, in good agreement with the measured one (3.424(1) Å). - Highlights: • Electronic structure, chemical bonding, and electron charge density were studied. • Density of states at Fermi level is 5.50 (3.45) states/Ry cell, for LDA (EVGGA). • Bare electronic specific heat coefficient is 0.95 (0.59) mJ/mole-K{sup 2} for LDA(EVGGA). • There are two independent molecules (A and B) in the asymmetric unit.

  8. Impact of electron delocalization on the nature of the charge-transfer states in model pentacene/C60 Interfaces: A density functional theory study

    KAUST Repository

    Yang, Bing

    2014-12-04

    Electronic delocalization effects have been proposed to play a key role in photocurrent generation in organic photovoltaic devices. Here, we study the role of charge delocalization on the nature of the charge-transfer (CT) states in the case of model complexes consisting of several pentacene molecules and one fullerene (C60) molecule, which are representative of donor/acceptor heterojunctions. The energies of the CT states are examined by means of time-dependent density functional theory (TD-DFT) using the long-range-corrected functional, ωB97X, with an optimized range-separation parameter, ω. We provide a general description of how the nature of the CT states is impacted by molecular packing (i.e., interfacial donor/acceptor orientations), system size, and intermolecular interactions, features of importance in the understanding of the charge-separation mechanism.

  9. Molecular electronegativity in density functional theory (I)——Direct calculation of atomic charges in a molecule via electronegativity equalization principle

    Institute of Scientific and Technical Information of China (English)

    杨忠志; 沈尔忠

    1995-01-01

    On the basis of electronegativity expressed in density functional theory and electronegativity equalization principle, a new scheme for calculating the atomic charges in a molecule has been proposed and designed, which gives a new scale of the atomic electronegativity and hardness in a certain molecular environment and takes the harmonic mean electronegativity as a reference value of the molecular electronegativity so that the multiple-regression and nonuniform parameters in the original method are avoided. This approach can be easily and widely applied to the calculation of atomic charges for a big molecule and quite good results of atomic charges in some illustrated molecules are obtained as compared with those from the ab initio STO-3G SCF calculations.

  10. Test Facility for Volumetric Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, M.; Dibowski, G.; Pfander, M.; Sack, J. P.; Schwarzbozl, P.; Ulmer, S.

    2006-07-01

    Long-time testing of volumetric absorber modules is an inevitable measure to gain the experience and reliability required for the commercialization of the open volumetric receiver technology. While solar tower test facilities are necessary for performance measurements of complete volumetric receivers, the long-term stability of individual components can be tested in less expensive test setups. For the qualification of the aging effects of operating cycles on single elements of new absorber materials and designs, a test facility was developed and constructed in the framework of the KOSMOSOL project. In order to provide the concentrated solar radiation level, the absorber test facility is integrated into a parabolic dish system at the Plataforma Solar de Almeria (PSA) in Spain. Several new designs of ceramic absorbers were developed and tested during the last months. (Author)

  11. Probing the momentum-dependent response of the charge density wave phase in TbTe{sub 3} by ultrafast time- and angle-resolved photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Kirchmann, P.S. [Department of Applied Physics, Stanford University, Stanford, CA (United States); Fachbereich Physik, Freie Universitaet Berlin (Germany); Schmitt, F.T.; Moore, R.G.; Chu, J.H.; Ru, N.; Fisher, I.R.; Shen, Z.X. [Department of Applied Physics, Stanford University, Stanford, CA (United States); Bovensiepen, U. [Fachbereich Physik, Freie Universitaet Berlin (Germany); Universitaet Duisburg-Essen, Institut fuer Experimentelle Physik, Duisburg (Germany); Rettig, L.; Krenz, M. [Fachbereich Physik, Freie Universitaet Berlin (Germany); Perfetti, L. [Fachbereich Physik, Freie Universitaet Berlin (Germany); Ecole Polytechnique, Palaiseau (France); Wolf, M. [Fachbereich Physik, Freie Universitaet Berlin (Germany); Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany)

    2010-07-01

    Charge density wave (CDW) systems such as TbTe{sub 3} offer fascinating options for studying the correlation of electrons and the lattice. We investigate the ultrafast response of the charge density wave (CDW) phase in TbTe{sub 3} after femtosecond IR excitation using time- and angle-resolved photoemission. The time-dependent photoemission intensity at the Fermi level yields a characteristic time for the closing of the CDW bandgap. With increasing laser fluence the bandgap closes faster, pointing to an increasing slope of the excited potential energy surface. As function of electron momentum the amplitude of the response increases strongly at the position of the Fermi wave vector k{sub F}. These results vividly demonstrate that the CDW system is most susceptible to electronic excitations near k{sub F} and that these electronic perturbations drive collective excitations of the coupled electron-lattice system.

  12. Far-from-equilibrium dynamics of a strongly coupled non-Abelian plasma with non-zero charge density or external magnetic field

    CERN Document Server

    Fuini, John F

    2015-01-01

    Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled N=4 supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibratio...

  13. Far-from-equilibrium dynamics of a strongly coupled non-Abelian plasma with non-zero charge density or external magnetic field

    Science.gov (United States)

    Fuini, John F.; Yaffe, Laurence G.

    2015-07-01

    Using holography, we study the evolution of a spatially homogeneous, far from equilibrium, strongly coupled supersymmetric Yang-Mills plasma with a non-zero charge density or a background magnetic field. This gauge theory problem corresponds, in the dual gravity description, to an initial value problem in Einstein-Maxwell theory with homogeneous but anisotropic initial conditions. We explore the dependence of the equilibration process on different aspects of the initial departure from equilibrium and, while controlling for these dependencies, examine how the equilibration dynamics are affected by the presence of a non-vanishing charge density or an external magnetic field. The equilibration dynamics are remarkably insensitive to the addition of even large chemical potentials or magnetic fields; the equilibration time is set primarily by the form of the initial departure from equilibrium. For initial deviations from equilibrium which are well localized in scale, we formulate a simple model for equilibration times which agrees quite well with our results.

  14. Modeling the effect of charge density in the active layers of reverse osmosis and nanofiltration membranes on the rejection of arsenic(III) and potassium iodide.

    Science.gov (United States)

    Coronell, Orlando; Mi, Baoxia; Mariñas, Benito J; Cahill, David G

    2013-01-02

    We used an extended solution-diffusion model that incorporates Donnan electrostatic exclusion of ions and unhindered advection due to imperfections, and measurements of charge density in the polyamide active layers of reverse osmosis (RO) and nanofiltration (NF) membranes, to predict the rejection of a strong electrolyte (i.e., potassium iodide) and a weak acid (i.e., arsenious acid) as a function of the pH of the feed aqueous solution. Predictions of solute rejection were in agreement with experimental data indicating that (i) the extended solution-diffusion model taking into account Donnan exclusion and unhindered advection due to imperfections satisfactorily describes the effect of pH on solute rejection by RO/NF membranes and (ii) measurement of charge density in active layers provides a valuable characterization of RO/NF membranes. Our results and analysis also indicate that independent ions, and not ion pairs, dominate the permeation of salts.

  15. Charged-Particle Multiplicity Density at Midrapidity in Central Pb-Pb Collisions at sNN=2.76TeV

    Science.gov (United States)

    Aamodt, K.; Abelev, B.; Abrahantes Quintana, A.; Adamová, D.; Adare, A. M.; Aggarwal, M. M.; Aglieri Rinella, G.; Agocs, A. G.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad Masoodi, A.; Ahmad, N.; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaráz Aviña, E.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Anguelov, V.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arbor, N.; Arcelli, S.; Arend, A.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Asryan, A.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Äystö, J.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldini Ferroli, R.; Baldisseri, A.; Baldit, A.; Baltasar Dos Santos Pedrosa, F.; Bán, J.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Bathen, B.; Batigne, G.; Batyunya, B.; Baumann, C.; Bearden, I. G.; Beck, H.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdermann, E.; Berdnikov, Y.; Bergmann, C.; Betev, L.; Bhasin, A.; Bhati, A. K.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biolcati, E.; Blanc, A.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Boccioli, M.; Bock, N.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Boldizsár, L.; Bombara, M.; Bombonati, C.; Book, J.; Borel, H.; Borissov, A.; Bortolin, C.; Bose, S.; Bossú, F.; Botje, M.; Böttger, S.; Boyer, B.; Braun-Munzinger, P.; Bravina, L.; Bregant, M.; Breitner, T.; Broz, M.; Brun, R.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bugaiev, K.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Cara Romeo, G.; Carena, F.; Carena, W.; Carminati, F.; Casanova Díaz, A.; Caselle, M.; Castillo Castellanos, J.; Catanescu, V.; Cavicchioli, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chiavassa, E.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Coccetti, F.; Coffin, J.-P.; Coli, S.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Constantin, P.; Contin, G.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Cotallo, M. E.; Crescio, E.; Crochet, P.; Cuautle, E.; Cunqueiro, L.; Erasmo, G. D.; Dainese, A.; Dalsgaard, H. H.; Danu, A.; Das, D.; Das, I.; Das, K.; Dash, A.; Dash, S.; de, S.; de Azevedo Moregula, A.; de Barros, G. O. V.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; de Marco, N.; de Pasquale, S.; de Remigis, R.; de Rooij, R.; Debski, P. R.; Del Castillo Sanchez, E.; Delagrange, H.; Delgado Mercado, Y.; Dellacasa, G.; Deloff, A.; Demanov, V.; Dénes, E.; Deppman, A.; di Bari, D.; di Giglio, C.; di Liberto, S.; di Mauro, A.; di Nezza, P.; Dietel, T.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domínguez, I.; Dönigus, B.; Dordic, O.; Driga, O.; Dubey, A. K.; Dubuisson, J.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Dutta Majumdar, M. R.; Elia, D.; Emschermann, D.; Engel, H.; Erdal, H. A.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evrard, S.; Eyyubova, G.; Fabjan, C. W.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fearick, R.; Fedunov, A.; Fehlker, D.; Fekete, V.; Felea, D.; Feofilov, G.; Fernández Téllez, A.; Ferretti, A.; Ferretti, R.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Fini, R.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Fragkiadakis, M.; Frankenfeld, U.; Fuchs, U.; Furano, F.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gadrat, S.; Gagliardi, M.; Gago, A.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Ganti, M. S.; Garabatos, C.; Garcia-Solis, E.; Garishvili, I.; Gemme, R.; Gerhard, J.; Germain, M.; Geuna, C.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Gianotti, P.; Girard, M. R.; Giraudo, G.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez, R.; Ferreiro, E. G.; González Santos, H.; González-Trueba, L. H.; González-Zamora, P.; Gorbunov, S.; Gotovac, S.; Grabski, V.; Grajcarek, R.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gros, P.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerra Gutierrez, C.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Gutbrod, H.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Harris, J. W.; Hartig, M.; Hasch, D.; Hasegan, D.; Hatzifotiadou, D.; Hayrapetyan, A.; Heide, M.; Heinz, M.; Helstrup, H.; Herghelegiu, A.; Hernández, C.; Herrera Corral, G.; Herrmann, N.; Hetland, K. F.; Hicks, B.; Hille, P. T.; Hippolyte, B.; Horaguchi, T.; Hori, Y.; Hristov, P.; Hřivnáčová, I.; Huang, M.; Huber, S.; Humanic, T. J.; Hwang, D. S.; Ichou, R.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Incani, E.; Innocenti, G. M.; Innocenti, P. G.; Ippolitov, M.; Irfan, M.; Ivan, C.; Ivanov, A.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jancurová, L.; Jangal, S.; Janik, R.; Jena, S.; Jirden, L.; Jones, G. T.; Jones, P. G.; Jovanović, P.; Jung, H.; Jung, W.; Jusko, A.; Kalcher, S.; Kaliňák, P.; Kalisky, M.; Kalliokoski, T.; Kalweit, A.; Kamermans, R.; Kanaki, K.; Kang, E.; Kang, J. H.; Kaplin, V.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kazantsev, A.; Kebschull, U.; Keidel, R.; Khan, M. M.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, D. J.; Kim, D. S.; Kim, D. W.; Kim, H. N.; Kim, J. H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, S. H.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kliemant, M.; Klovning, A.; Kluge, A.; Knichel, M. L.; Koch, K.; Köhler, M. K.; Kolevatov, R.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskih, A.; Kornaś, E.; Kottachchi Kankanamge Don, C.; Kour, R.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kozlov, K.; Kral, J.; Králik, I.; Kramer, F.; Kraus, I.; Krawutschke, T.; Kretz, M.; Krivda, M.; Krizek, F.; Krumbhorn, D.; Krus, M.; Kryshen, E.; Krzewicki, M.; Kucheriaev, Y.; Kuhn, C.; Kuijer, P. G.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kushpil, V.; Kweon, M. J.; Kwon, Y.; La Rocca, P.; Ladrón de Guevara, P.; Lafage, V.; Lara, C.; Lardeux, A.; Larsen, D. T.; Lazzeroni, C.; Le Bornec, Y.; Lea, R.; Lee, K. S.; Lee, S. C.; Lefèvre, F.; Lehnert, J.; Leistam, L.; Lenhardt, M.; Lenti, V.; León Monzón, I.; León Vargas, H.; Lévai, P.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Liu, L.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohn, S.; Loizides, C.; Loo, K. K.; Lopez, X.; López Noriega, M.; López Torres, E.; Løvhøiden, G.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Luquin, L.; Luzzi, C.; Ma, K.; Ma, R.; Madagodahettige-Don, D. M.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Maire, A.; Mal'Kevich, D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Malzacher, P.; Mamonov, A.; Manceau, L.; Mangotra, L.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Martashvili, I.; Martinengo, P.; Martínez, M. I.; Martínez Davalos, A.; Martínez García, G.; Martynov, Y.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastromarco, M.; Mastroserio, A.; Matthews, Z. L.; Matyja, A.; Mayani, D.; Mayer, C.; Mazza, G.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Mendez Lorenzo, P.; Menis, I.; Mercado Pérez, J.; Meres, M.; Mereu, P.; Miake, Y.; Midori, J.; Milano, L.; Milosevic, J.; Mischke, A.; Miśkowiec, D.; Mitu, C.; Mlynarz, J.; Mohanty, A. K.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Monteno, M.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moretto, S.; Morsch, A.; Muccifora, V.; Mudnic, E.; Muhuri, S.; Müller, H.; Munhoz, M. G.; Munoz, J.; Musa, L.; Musso, A.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Navach, F.; Navin, S.; Nayak, T. K.; Nazarenko, S.; Nazarov, G.; Nedosekin, A.; Nendaz, F.; Newby, J.; Nicassio, M.; Nielsen, B. S.; Niida, T.; Nikolaev, S.; Nikolic, V.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Nilsson, M. S.; Noferini, F.; Nooren, G.; Novitzky, N.; Nyanin, A.; Nyatha, A.; Nygaard, C.; Nystrand, J.; Obayashi, H.; Ochirov, A.; Oeschler, H.; Oh, S. K.; Oleniacz, J.; Oppedisano, C.; Ortiz Velasquez, A.; Ortona, G.; Oskarsson, A.; Ostrowski, P.; Otterlund, I.; Otwinowski, J.; Oyama, K.; Ozawa, K.; Pachmayer, Y.; Pachr, M.; Padilla, F.; Pagano, P.; Jayarathna, S. P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S.; Pal, S. K.; Palaha, A.; Palmeri, A.; Pappalardo, G. S.; Park, W. J.; Patalakha, D. I.; Paticchio, V.; Pavlinov, A.; Pawlak, T.; Peitzmann, T.; Peresunko, D.; Pérez Lara, C. E.; Perini, D.; Perrino, D.; Peryt, W.; Pesci, A.; Peskov, V.; Pestov, Y.; Peters, A. J.; Petráček, V.; Petran, M.; Petris, M.; Petrov, P.; Petrovici, M.; Petta, C.; Piano, S.; Piccotti, A.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Pitz, N.; Piuz, F.; Piyarathna, D. B.; Platt, R.; Płoskoń, M.; Pluta, J.; Pocheptsov, T.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polák, K.; Polichtchouk, B.; Pop, A.; Porteboeuf, S.; Pospíšil, V.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pulvirenti, A.; Punin, V.; Putiš, M.; Putschke, J.; Quercigh, E.; Qvigstad, H.; Rachevski, A.; Rademakers, A.; Rademakers, O.; Radomski, S.; Räihä, T. S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Ramírez Reyes, A.; Rammler, M.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Read, K. F.; Real, J.; Redlich, K.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Ricaud, H.; Riccati, L.; Ricci, R. A.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rodríguez Cahuantzi, M.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Rosinský, P.; Rosnet, P.; Rossegger, S.; Rossi, A.; Roukoutakis, F.; Rousseau, S.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Rivetti, A.; Rusanov, I.; Ryabinkin, E.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahoo, R.; Sahu, P. K.; Saini, J.; Saiz, P.; Sakai, S.; Sakata, D.; Salgado, C. A.; Samanta, T.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Sano, S.; Santo, R.; Santoro, R.; Sarkamo, J.; Saturnini, P.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schreiner, S.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, P. A.; Scott, R.; Segato, G.; Selyuzhenkov, I.; Senyukov, S.; Seo, J.; Serci, S.; Serradilla, E.; Sevcenco, A.; Sgura, I.; Shabratova, G.; Shahoyan, R.; Sharma, N.; Sharma, S.; Shigaki, K.; Shimomura, M.; Shtejer, K.; Sibiriak, Y.; Siciliano, M.; Sicking, E.; Siemiarczuk, T.; Silenzi, A.; Silvermyr, D.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Smakal, R.; Smirnov, N.; Snellings, R.; Søgaard, C.; Soloviev, A.; Soltz, R.; Son, H.; Song, J.; Song, M.; Soos, C.; Soramel, F.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Stefanini, G.; Steinbeck, T.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stocco, D.; Stock, R.; Stokkevag, C. H.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A. P.; Subieta Vásquez, M. A.; Sugitate, T.; Suire, C.; Sukhorukov, M.; Šumbera, M.; Susa, T.; Swoboda, D.; Symons, T. J. M.; Szanto de Toledo, A.; Szarka, I.; Szostak, A.; Tagridis, C.; Takahashi, J.; Tapia Takaki, J. D.; Tauro, A.; Tavlet, M.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Thomas, J. H.; Tieulent, R.; Timmins, A. R.; Tlusty, D.; Toia, A.; Torii, H.; Toscano, L.; Tosello, F.; Traczyk, T.; Truesdale, D.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Turvey, A. J.; Tveter, T. S.; Ulery, J.; Ullaland, K.; Uras, A.; Urbán, J.; Urciuoli, G. M.; Usai, G. L.; Vacchi, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Kolk, N.; van Leeuwen, M.; Vande Vyvre, P.; Vannucci, L.; Vargas, A.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Venaruzzo, M.; Vercellin, E.; Vergara, S.; Vernekohl, D. C.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Vikhlyantsev, O.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Voloshin, K.; Voloshin, S.; Volpe, G.; von Haller, B.; Vranic, D.; Øvrebekk, G.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, V.; Wan, R.; Wang, D.; Wang, Y.; Wang, Y.; Watanabe, K.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, A.; Wilk, G.; Williams, M. C. S.; Windelband, B.; Xaplanteris Karampatsos, L.; Yang, H.; Yang, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yu, W.; Yuan, X.; Yushmanov, I.; Zabrodin, E.; Zach, C.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zelnicek, P.; Zenin, A.; Zgura, I.; Zhalov, M.; Zhang, X.; Zhou, D.; Zichichi, A.; Zinovjev, G.; Zoccarato, Y.; Zynovyev, M.

    2010-12-01

    The first measurement of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair sNN=2.76TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section, the pseudorapidity density of primary charged particles at midrapidity is 1584±4(stat)±76(syst), which corresponds to 8.3±0.4(syst) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at sNN=0.2TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.

  16. Charged-particle multiplicity density at mid-rapidity in central Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV

    CERN Document Server

    Aamodt, K; Abrahantes Quintana, A; Adamova, D; Adare, A M; Aggarwal, M M; Aglieri Rinella, G; Agocs, A G; Aguilar Salazar, S; Ahammed, Z; Ahmad Masoodi, A; Ahmad, N; Ahn, S U; Akindinov, A; Aleksandrov, D; Alessandro, B; Alfaro Molina, R; Alici, A; Alkin, A; Almaraz Avina, E; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Andrei, C; Andronic, A; Anguelov, V; Anson, C; Anticic, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshauser, H; Arbor, N; Arcelli, S; Arend, A; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Asryan, A; Augustinus, A; Averbeck, R; Awes, T C; Aysto, J; Azmi, M D; Bach, M; Badala, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Baldini-Ferroli, R; Baldisseri, A; Baldit, A; Baltasar Dos Santos Pedrosa, F; Ban, J; Barbera, R; Barile, F; Barnafoldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Bathen, B; Batigne, G; Batyunya, B; Baumann, C; Bearden, I G; Beck, H; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Beole, S; Berceanu, I; 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Yushmanov, I; Zabrodin, E; Zach, C; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Zavada, P; Zaviyalov, N; Zbroszczyk, H; Zelnicek, P; Zenin, A; Zgura, I; Zhalov, M; Zhang, X; Zhou, D; Zichichi, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M

    2010-01-01

    The first measurement of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at a centre-of-mass energy per nucleon pair sqrt(sNN) = 2.76 TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section the pseudo-rapidity density of primary charged particles at mid-rapidity is 1584 +- 4 (stat) +- 76 (sys.), which corresponds to 8.3 +- 0.4 (sys.) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at sqrt(sNN) = 0.2 TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.

  17. Ab initio full charge-density study of the atomic volume of α-phase Fr, Ra, Ac, Th, Pa, U, Np, and Pu

    DEFF Research Database (Denmark)

    Vitos, Levente; Kollár, J.; Skriver, Hans Lomholt

    1997-01-01

    We have used a full charge-density technique based on the linear muffin-tin orbitals method in first-principles calculations of the atomic volumes of the light actinides including Fr, Ra, and Ac in their low-temperature crystallographic phases. The good agreement between the theoretical and exper...... and experimental values along the series support the picture of itinerant 5f electronic states in Th to Pu. The increased deviation between theory and experiment found in Np and Pu may be an indication of correlation effects not included in the local density approximation....

  18. Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at sNN=5.02TeV

    NARCIS (Netherlands)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaraz, J. R. M.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.|info:eu-repo/dai/nl/411263188; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-moreno, E.; Belyaev, V.; Benacek, P.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.|info:eu-repo/dai/nl/371578248; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Bjelogrlic, S.|info:eu-repo/dai/nl/355079615; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Bourjau, C.; Braun-munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.|info:eu-repo/dai/nl/411885812; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; De Cataldo, G.; De Conti, C.; De Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.|info:eu-repo/dai/nl/372618715; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.|info:eu-repo/dai/nl/355502488; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-solis, E.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, A.; Gheata, M.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, V.; González-zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.

    2016-01-01

    The pseudorapidity density of charged particles, dN ch /dη , at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of s NN − − − − √ =5.02  TeV . For the 5% most central collisions, we measure a value of 1943±54 . The rise in dN ch /dη as a function of s NN

  19. Photon-induced near-field electron microscopy: Mathematical formulation of the relation between the experimental observables and the optically driven charge density of nanoparticles

    Science.gov (United States)

    Park, Sang Tae; Zewail, Ahmed H.

    2014-01-01

    Photon-induced near-field electron microscopy (PINEM) enables the visualization of the plasmon fields of nanoparticles via measurement of photon-electron interaction [S. T. Park et al., New J. Phys. 12, 123028 (2010), 10.1088/1367-2630/12/12/123028]. In this paper, the field integral, which is a mechanical work performed on a fast electron by the total electric field, plays a key role in understanding the interaction. Here, we reexamine the field integral and give the physical meaning by decomposing the contribution of the field from the charge-density distribution. It is found that the "near-field integral" (the near-field approximation of the field integral) can be expressed as a convolution of the two-dimensional projection of the optically driven charge-density distribution in the nanoparticle with a broad radial response function. This approach, which we call the "convolution method," is validated by applying it to Rayleigh scattering cases, where previous analytical expressions for the field integrals in near-field approximations are reproduced by the convolution method. The convolution method is applied to discrete dipole approximation calculations of a silver nanorod, and the nature of the induced charge-density distributions of its plasmons is discussed.

  20. Model-independent measurement of the charge density distribution along an Fe atom probe needle using off-axis electron holography without mean inner potential effects

    Energy Technology Data Exchange (ETDEWEB)

    Migunov, V., E-mail: v.migunov@fz-juelich.de; Dunin-Borkowski, R. E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich (Germany); London, A. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Farle, M. [Fakultät für Physik and Center of Nanointegration (CeNIDE), Universität Duisburg-Essen, D-47048 Duisburg (Germany)

    2015-04-07

    The one-dimensional charge density distribution along an electrically biased Fe atom probe needle is measured using a model-independent approach based on off-axis electron holography in the transmission electron microscope. Both the mean inner potential and the magnetic contribution to the phase shift are subtracted by taking differences between electron-optical phase images recorded with different voltages applied to the needle. The measured one-dimensional charge density distribution along the needle is compared with a similar result obtained using model-based fitting of the phase shift surrounding the needle. On the assumption of cylindrical symmetry, it is then used to infer the three-dimensional electric field and electrostatic potential around the needle with ∼10 nm spatial resolution, without needing to consider either the influence of the perturbed reference wave or the extension of the projected potential outside the field of view of the electron hologram. The present study illustrates how a model-independent approach can be used to measure local variations in charge density in a material using electron holography in the presence of additional contributions to the phase, such as those arising from changes in mean inner potential and specimen thickness.

  1. Charge density waves as the origin of dip-hump structures in the differential tunneling conductance of cuprates: The case of d-wave superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gabovich, Alexander M., E-mail: gabovich@iop.kiev.ua; Voitenko, Alexander I., E-mail: voitenko@iop.kiev.ua

    2014-08-15

    Highlights: • d-Wave superconductivity and charge-density waves compete for the Fermi surface. • Charge-density waves induce pseudogaps and peak-dip-hump structures in cuprates. • Tunnel spectra are non-symmetric due to the dielectric order-parameter phase fixation. • Scatter of the dielectric order parameter smears the tunnel spectra peculiarities. - Abstract: Quasiparticle differential current–voltage characteristics (CVCs) G(V) of non-symmetric tunnel junctions between d-wave superconductors with charge-density waves (CDWs) and normal metals were calculated. The dependences G(V) were shown to have a V-like form at small voltages V and low temperatures, and to be asymmetric at larger V owing to the presence of CDW peak in either of the V-branches. The spatial scatter of the dielectric (CDW) order parameter smears the CDW peak into a hump and induces a peak-dip-hump structure (PDHS) typical of CVCs observed for such junctions. At temperatures larger than the superconducting critical one, the PDHS evolves into a pseudogap depression. The results agree well with the scanning tunneling microscopy data for Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+δ} and YBa{sub 2}Cu{sub 3}O{sub 7−δ}. The results differ substantially from those obtained earlier for CDW s-wave superconductors.

  2. Experimental research on colloid titration determination of PAC charge density%胶体滴定测定PAC电荷密度的实验研究

    Institute of Scientific and Technical Information of China (English)

    邵青; 冷超群

    2014-01-01

    通过胶体滴定法对固体和液体PAC产品进行实验,研究了PAC浓度、pH、盐基度等因素对电荷密度测定的影响规律;当实验pH为5.5左右,混凝剂质量浓度为10~25 mg/L,采用返滴定法可测定PAC的电荷密度。通过对湖水和染料水溶液的混凝脱色实验,表明电荷密度高的PAC产品浊度去除率、脱色率高。%Solid and liquid PAC products are te sted by colloid titration. The rules of influences of PAC concentra-tion,pH,basicity and other factors on the determination of electric charge density are studied. When the pH tested is about 5.5,and coagulant mass concentration 10-25 mg/L,the back titration method could be adopted to determine the charge density of PAC. The coagulation and decolorization experiments of the lake water and the dye aqueous so-lution illustrate that the higher charge density of the PAC products is ,the higher the turbidity removing rate and the decolorization rate are.

  3. Investigation of space charge distribution of low-density polyethylene/GO-GNF (graphene oxide from graphite nanofiber) nanocomposite for HVDC application.

    Science.gov (United States)

    Kim, Yoon Jin; Ha, Son-Tung; Lee, Gun Joo; Nam, Jin Ho; Ryu, Ik Hyun; Nam, Su Hyun; Park, Cheol Min; In, Insik; Kim, Jiwan; Han, Chul Jong

    2013-05-01

    This paper reported a research on space charge distribution in low-density polyethylene (LDPE) nanocomposites with different types of graphene and graphene oxide (GO) at low filler content (0.05 wt%) under high DC electric field. Effect of addition of graphene oxide or graphene, its dispersion in LDPE polymer matrix on the ability to suppress space charge generation will be investigated and compared with MgO/LDPE nanocomposite at the same filler concentration. At an applied electric field of 80 kV/mm, a positive packet-like charge was observed in both neat LDPE, MgO/LDPE, and graphene/LDPE nanocomposites, whereas only little homogenous space charge was observed in GO/LDPE nanocomposites, especially with GO synthesized from graphite nano fiber (GNF) which is only -100 nm in diameter. Our research also suggests that dispersion of graphene oxide particles on the polymer matrix plays a significant role to the performance of nanocomposites on suppressing packet-like space charge. From these results, it is expected that nano-sized GO synthesized from GNF can be a promising filler material to LDPE composite for HVDC applications.

  4. Real-time density matrix renormalization group dynamics of spin and charge transport in push-pull polyenes and related systems

    Science.gov (United States)

    Dutta, Tirthankar; Ramasesha, S.

    2012-01-01

    In this paper we investigate the effect of terminal substituents on the dynamics of spin and charge transport in donor-acceptor substituted polyenes [D-(CH)x-A] chains, also known as push-pull polyenes. We employ a long-range correlated model Hamiltonian for the D-(CH)x-A system, and time-dependent density matrix renormalization group technique for time propagating the wave packet obtained by injecting a hole at a terminal site, in the ground state of the system. Our studies reveal that the end groups do not affect spin and charge velocities in any significant way, but change the amount of charge transported. We have compared these push-pull systems with donor-acceptor substituted polymethine imine (PMI), D-(CHN)x-A, systems in which besides electron affinities, the nature of pz orbitals in conjugation also alternate from site to site. We note that spin and charge dynamics in the PMIs are very different from that observed in the case of push-pull polyenes, and within the time scale of our studies, transport of spin and charge leads to the formation of a “quasi-static” state.

  5. Surface charge dynamics and OH and H number density distributions in near-surface nanosecond pulse discharges at a liquid / vapor interface

    Science.gov (United States)

    Winters, Caroline; Petrishchev, Vitaly; Yin, Zhiyao; Lempert, Walter R.; Adamovich, Igor V.

    2015-10-01

    The present work provides insight into surface charge dynamics and kinetics of radical species reactions in nanosecond pulse discharges sustained at a liquid-vapor interface, above a distilled water surface. The near-surface plasma is sustained using two different discharge configurations, a surface ionization wave discharge between two exposed metal electrodes and a double dielectric barrier discharge. At low discharge pulse repetition rates (~100 Hz), residual surface charge deposition after the discharge pulse is a minor effect. At high pulse repetition rates (~10 kHz), significant negative surface charge accumulation over multiple discharge pulses is detected, both during alternating polarity and negative polarity pulse trains. Laser induced fluorescence (LIF) and two-photon absorption LIF (TALIF) line imaging are used for in situ measurements of spatial distributions of absolute OH and H atom number densities in near-surface, repetitive nanosecond pulse discharge plasmas. Both in a surface ionization wave discharge and in a double dielectric barrier discharge, peak measured H atom number density, [H] is much higher compared to peak OH number density, due to more rapid OH decay in the afterglow between the discharge pulses. Higher OH number density was measured near the regions with higher plasma emission intensity. Both OH and especially H atoms diffuse out of the surface ionization wave plasma volume, up to several mm from the liquid surface. Kinetic modeling calculations using a quasi-zero-dimensional H2O vapor / Ar plasma model are in qualitative agreement with the experimental data. The results demonstrate the experimental capability of in situ radical species number density distribution measurements in liquid-vapor interface plasmas, in a simple canonical geometry that lends itself to the validation of kinetic models.

  6. Coherent charge and spin density waves in underdoped HgBa2CuO4+δ

    Science.gov (United States)

    Lee, Jeongseop A.; Xin, Yizhou; Halperin, W. P.; Reyes, A. P.; Kuhns, P. L.; Chan, M. K.

    2017-03-01

    Charge order in cuprate superconductors appears to be a universal characteristic, often associated with pseudogap behavior in the normal state. The central question is whether such charge ordering or the pseudogap are required for the existence of high temperature superconductivity and embody its mechanism. An important but phenomenological approach to this question is to examine whether these phenomena extend over various members of the cuprate family. Recent nuclear magnetic resonance (NMR) measurements on oxygen chain-ordered single crystals of YBa2Cu3O6+y (Y123) have demonstrated temperature and magnetic field induced charge ordering that was confirmed in x-ray experiments. In the present work on high-quality single crystals of the tetragonal compound, HgBa2CuO4+δ , we use 17O NMR to investigate the interplay between charge and spin order deduced from the full quadrupolar-split NMR spectrum over a wide range of temperature and magnetic field. We have found evidence for a coherent modulation of charge and spin order in this compound. However, neither temperature nor magnetic field induced ordering was observed and we infer that this aspect of high temperature superconductivity is not universal.

  7. Method for Slater-Type Density Fitting for Intermolecular Electrostatic Interactions with Charge Overlap. I. The Model.

    Science.gov (United States)

    Öhrn, Anders; Hermida-Ramon, Jose M; Karlström, Gunnar

    2016-05-10

    The effects of charge overlap, or charge penetration, are neglected in most force fields and interaction terms in QM/MM methods. The effects are however significant at intermolecular distances near the van der Waals minimum. In the present study, we propose a method to evaluate the intermolecular Coloumb interaction using Slater-type functions, thus explicitly modeling the charge overlap. The computational cost of the method is low, which allows it to be used in large systems with most force fields as well as in QM/MM schemes. The charge distribution is modeled as a distributed multipole expansion up to quadrupole and Slater-type functions of angular momentum up to L = 1. The exponents of the Slater-type functions are obtained using a divide-and-conquer method to avoid the curse of dimensionality that otherwise is present for large nonlinear optimizations. A Levenberg-Marquardt algorithm is applied in the fitting process. A set of parameters is obtained for each molecule, and the process is fully automated. Calculations have been performed in the carbon monoxide and the water dimers to illustrate the model. Results show a very good accuracy of the model with relative errors in the electrostatic potential lower than 3% over all reasonable separations. At very short distances where the charge overlaps is the most significant, errors are lower than 8% and lower than 3.5% at distances near the van der Waals minimum.

  8. Conductive two-dimensional titanium carbide `clay' with high volumetric capacitance

    Science.gov (United States)

    Ghidiu, Michael; Lukatskaya, Maria R.; Zhao, Meng-Qiang; Gogotsi, Yury; Barsoum, Michel W.

    2014-12-01

    Safe and powerful energy storage devices are becoming increasingly important. Charging times of seconds to minutes, with power densities exceeding those of batteries, can in principle be provided by electrochemical capacitors--in particular, pseudocapacitors. Recent research has focused mainly on improving the gravimetric performance of the electrodes of such systems, but for portable electronics and vehicles volume is at a premium. The best volumetric capacitances of carbon-based electrodes are around 300 farads per cubic centimetre; hydrated ruthenium oxide can reach capacitances of 1,000 to 1,500 farads per cubic centimetre with great cyclability, but only in thin films. Recently, electrodes made of two-dimensional titanium carbide (Ti3C2, a member of the `MXene' family), produced by etching aluminium from titanium aluminium carbide (Ti3AlC2, a `MAX' phase) in concentrated hydrofluoric acid, have been shown to have volumetric capacitances of over 300 farads per cubic centimetre. Here we report a method of producing this material using a solution of lithium fluoride and hydrochloric acid. The resulting hydrophilic material swells in volume when hydrated, and can be shaped like clay and dried into a highly conductive solid or rolled into films tens of micrometres thick. Additive-free films of this titanium carbide `clay' have volumetric capacitances of up to 900 farads per cubic centimetre, with excellent cyclability and rate performances. This capacitance is almost twice that of our previous report, and our synthetic method also offers a much faster route to film production as well as the avoidance of handling hazardous concentrated hydrofluoric acid.

  9. Conductive two-dimensional titanium carbide 'clay' with high volumetric capacitance.

    Science.gov (United States)

    Ghidiu, Michael; Lukatskaya, Maria R; Zhao, Meng-Qiang; Gogotsi, Yury; Barsoum, Michel W

    2014-12-04

    Safe and powerful energy storage devices are becoming increasingly important. Charging times of seconds to minutes, with power densities exceeding those of batteries, can in principle be provided by electrochemical capacitors--in particular, pseudocapacitors. Recent research has focused mainly on improving the gravimetric performance of the electrodes of such systems, but for portable electronics and vehicles volume is at a premium. The best volumetric capacitances of carbon-based electrodes are around 300 farads per cubic centimetre; hydrated ruthenium oxide can reach capacitances of 1,000 to 1,500 farads per cubic centimetre with great cyclability, but only in thin films. Recently, electrodes made of two-dimensional titanium carbide (Ti3C2, a member of the 'MXene' family), produced by etching aluminium from titanium aluminium carbide (Ti3AlC2, a 'MAX' phase) in concentrated hydrofluoric acid, have been shown to have volumetric capacitances of over 300 farads per cubic centimetre. Here we report a method of producing this material using a solution of lithium fluoride and hydrochloric acid. The resulting hydrophilic material swells in volume when hydrated, and can be shaped like clay and dried into a highly conductive solid or rolled into films tens of micrometres thick. Additive-free films of this titanium carbide 'clay' have volumetric capacitances of up to 900 farads per cubic centimetre, with excellent cyclability and rate performances. This capacitance is almost twice that of our previous report, and our synthetic method also offers a much faster route to film production as well as the avoidance of handling hazardous concentrated hydrofluoric acid.

  10. The knee in the cosmic ray energy spectrum from the simultaneous EAS charged particles and muon density spectra

    Science.gov (United States)

    Bijay, Biplab; Banik, Prabir; Bhadra, Arunava

    2016-09-01

    In this work we examine with the help of Monte Carlo simulation whether a consistent primary energy spectrum of cosmic rays emerges from both the experimentally observed total charged particles and muon size spectra of cosmic ray extensive air showers considering primary composition may or may not change beyond the knee of the energy spectrum. It is found that EAS-TOP observations consistently infer a knee in the primary energy spectrum provided the primary is pure unchanging iron whereas no consistent primary spectrum emerges from simultaneous use of the KASCADE observed total charged particle and muon spectra. However, it is also found that when primary composition changes across the knee the estimation of spectral index of total charged particle spectrum is quite tricky, depends on the choice of selection of points near the knee in the size spectrum.

  11. The knee in the cosmic ray energy spectrum from the simultaneous EAS charged particles and muon density spectra

    CERN Document Server

    Bijay, Biplab; Bhadra, Arunava

    2015-01-01

    In this work we examine with the help of Monte Carlo simulation whether a consistent primary energy spectrum of cosmic rays emerges from both the experimentally observed total charged particles and muon size spectra of cosmic ray extensive air showers considering primary composition may or may not change beyond the knee of the energy spectrum. It is found that EAS-TOP observations consistently infer a knee in the primary energy spectrum provided the primary is pure unchanging iron whereas no consistent primary spectrum emerges from simultaneous use of the KASCADE observed total charged particle and muon spectra. However, it is also found that when primary composition changes across the knee the estimation of spectral index of total charged particle spectrum is quite tricky, depends on the choice of selection of points near the knee in the size spectrum.

  12. X-ray derived experimental charge density distribution in GaF{sub 3} and VF{sub 3} solid systems

    Energy Technology Data Exchange (ETDEWEB)

    Sujatha, K.; Israel, S., E-mail: israel.samuel@gmail.com; Anzline, C.; Niranjana Devi, R.; Sheeba, R.A.J.R.

    2016-09-01

    The electronic structure and bonding features of metal and transition metal fluorides in low oxidation states, GaF{sub 3} and VF{sub 3}, have been studied from precise single crystal X-ray diffraction data using multipole and maximum entropy methods. The topology of the charge density is analyzed and the (3,−1) bond critical points are determined. Existences of ionic nature of bonding in low valent fluorine compounds are clearly evident. The spherical core of metal atom and aspherical or twisted core of transition metal atom reveal the fact that GaF{sub 3} is much more rigid than VF{sub 3}. Aspherical cores of the polarized ligand atoms are also visible in the two-dimensional density distribution pictures. The true valence charge density surfaces with encapsulating the atomic basins maps are elucidated. An elongated saddle with mid-bond density of 0.6191 e/Å{sup 3}, observed in the compound VF{sub 3}, shows that its lattice is less rigid and has more ionic character than GaF{sub 3}.

  13. Centrality dependence of the pseudorapidity density distribution for charged particles in Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV

    CERN Document Server

    Abbas, Ehab; Adam, Jaroslav; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agocs, Andras Gabor; Agostinelli, Andrea; Ahammed, Zubayer; Ahmad, Arshad; Ahmad, Nazeer; Ahn, Sang Un; Ahn, Sul-Ah; Aimo, Ilaria; Ajaz, Muhammad; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Arend, Andreas; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Asryan, Andzhey; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Batzing, Paul Christoph; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Nicola; Bianchi, Livio; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, F; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Boccioli, Marco; Boettger, Stefan; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bossu, Francesco; Botje, Michiel; Botta, Elena; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Francesco; Carena, Wisla; Carlin Filho, Nelson; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Castillo Hernandez, Juan Francisco; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio; Colella, Domenico; Collu, Alberto; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Connors, Megan Elizabeth; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crescio, Elisabetta; Crochet, Philippe; Cruz Alaniz, Emilia; Cruz Albino, Rigoberto; Cuautle, Eleazar; Cunqueiro, Leticia; Dainese, Andrea; Dalsgaard, Hans Hjersing; Dang, Ruina; Danu, Andrea; Das, Kushal; Das, Indranil; Das, Supriya; Das, Debasish; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; Delagrange, Hugues; Deloff, Andrzej; De Marco, Nora; Denes, Ervin; De Pasquale, Salvatore; Deppman, Airton; D'Erasmo, Ginevra; de Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Di Bari, Domenico; Dietel, Thomas; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza