bluuebunny/crossref_metadata_2025 huggingface dataset:
Zum Einfluss der Härte von Brennschnittkanten auf die Haltbarkeit von Beschichtungen
Authors: Jost Katrin , Renner Anja , Lange Jörg
Published: September 2013

Die mittlerweile baurechtlich eingeführte DIN EN 1090‐2, die die Ausführung von Stahltragwerken regelt, gibt für Schnittflächen von Stahlblechen einen zulässigen höchsten Härtewert an. Solche Grenzwerte waren in den zuvor geltenden deutschen Normen nur aus der Schweißverfahrensprüfung bekannt. Da die gemessene Härte den neuen Grenzwert bei Schnittkanten, die mit den gängigen Schnittverfahren hergestellt wurden, oft überschreitet, stellt die neue Regelung die produzierenden Firmen vor große Probleme. Insbesondere bei planmäßig nicht weiterbearbeiteten Schnittkanten stellt sich die Frage, inwieweit die Aufhärtungen die Oberflächenvorbereitung für den Korrosionsschutz beeinträchtigen und sich negativ auf die Haftzugfestigkeit der Beschichtung auswirken. Um herauszufinden, welche Zusammenhänge hier bestehen, wurden an verschiedenen Brennschnittkanten Versuche zur Bestimmung der Härte und der Rauigkeit durchgeführt und der Einfluss der Kantenhärte auf die Haltbarkeit von Beschichtungen untersucht.

The influence of the hardness of heat cut edges. The meanwhile introduced DIN EN 1090‐2, which settles the execution of steel structures, gives a maximum permissible hardness value for cut edges of steel plates. In German standards comparable limit values where thitherto only known in conjunction with the welding procedure qualification. Due to the fact that the measured hardness on edges, which were cut with the established cutting methods, often exceeds this new maximum value, producing firms are faced with problems. Especially for edges that do not get milled the question arises, what influence the increase of hardness has on the surface preparation for anticorrosive coating and whether it has any effect on the adhesive tensile strength of the coating. To find out which correlations exist here, tests were conducted on different thermal cut edges. Hardness and roughness were measured and the influence of these values on the resistance of the coating was tested.
Sphäre Deutsche Bank, Frankfurt am Main
Authors: Castegini Giulio , Fahlbusch Mark , Tessmann Oliver , Drawer Olive , Arnold Uwe
Published: September 2013

Im Jahre 2006 hat Mario Bellini den Architekturwettbewerb für die Sanierung der Firmenzentrale der Deutschen Bank AG in Frankfurt am Main gewonnen. Unter seiner Leitung ist in der Eingangshalle eine herausragende Skulptur entstanden. Die Sphäre – der architektonische Mittelpunkt des neu gestalteten Foyers zwischen den beiden Türmen, symbolisiert Stabilität und Stärke, aber zugleich auch Dynamik und Wandel.

Der Entwurf des Architekten sah eine 16 m durchmessende Kugel vor, die mit Bändern umwickelt zu sein scheint und zwischen den beiden Türmen der Bank klemmt. Dieses Konzept wurde durch ein interdisziplinäres Team bestehend aus dem verantwortlichen Entwurfsarchitekt Giulio Castegini (Mario Bellini Architects), den Ingenieuren Oliver Tessmann und Mark Fahlbusch (Bollinger Grohmann Ingenieure) und Oliver Drawer der ausführenden Firma (Arnold AG) weiterentwickelt. Das Projektmanagement verantwortete Drees
Modernes Eisentragwerk über klassizistischem Rundbau
Authors: Möller Eberhard
Published: September 2013

Die Befreiungshalle bei Kelheim nahe Regensburg zählt zu den bedeutendsten politischen Monumentalbauten des 19. Jahrhunderts. Vor 150 Jahren, am 18. Oktober 1863, findet die Einweihung statt. Es ist zugleich der 50. Jahrestag der Völkerschlacht bei Leipzig. Der bayerische König Ludwig I. hatte den Bau 1836 bei seinem favorisierten Architekten Friedrich von Gärtner (1791–1847) in Auftrag gegeben, zum einen, um an den Sieg über Napoleon zu erinnern, aber auch, um einer “größeren deutschen Nation“ ein Denkmal zu errichten, um einen “Pantheon der Teutschen“ zu bauen (Bild 1). Im Archäologischen Museum der Stadt Kelheim präsentiert das Architekturmuseum der TU München bis zum 27. Oktober 2013 alle wichtigen originalen Zeichnungen und Pläne aus der Bauzeit (Bild 2).

The Hall of Liberation near Kelheim – Modern iron architecture over classicist rotunda. The Befreiungshalle (Hall of Liberation) near Kelheim in Bavaria is one of the most important 19th century monuments. 150 years ago, on 18 October 1863, the inauguration takes place. It is the 50th Anniversary of the Battle of Leipzig. The Bavarian King Ludwig I had ordered the construction in 1836 at his favorite architect Friedrich von Gärtner (1791–1847) in order to commemorate the victory over Napoleon, but also to build a monument towards a “larger German nation”, a “Pantheon of the Germans”. At the Archäologisches Museum Kelheim an exhibition shows all important original sketches, coloured drawings and plans till 27 October 2013.
Syntheses, Structural Characterization, and Properties of Mixed‐valent CoIICoIII and ZnII Coordination Polymers from 5‐(4‐Carboxybenzylamino)isophthalic Acid
Authors: Kuai Hai‐Wei , Cheng Xiao‐Chun , Feng Liang‐Dong , Zhu Xiao‐Hong
Published: September 2013

The reaction of cobalt(II) and zinc(II) salts with 5‐(4‐carboxybenzylamino)isophthalic acid (H3L) in the presence of 1,2‐bis(pyridin‐4‐yl)ethane (bpa) as auxiliary co‐ligand under hydrothermal synthetic condition led to the formation of two complexes, {[(CoII)0.25(CoIII)0.5(HL)(H2O)0.5(bpa)0.25]·2.5H2O}n (1) and [Zn(HL)(bpa)0.5]n (2), which were characterized by single crystal and powder X‐ray diffraction, IR spectroscopy as well as elemental and thermogravimetric analyses. Complex 1 displays uninodal 4‐connected 2D sql network with (44.62) topology, complex 2 is binodal (3, 6)‐connected 2D (4.62)2(42.610.83) network. Interestingly, complex 1 shows structural features consistent with the Jahn‐Teller distortions, whereas in 2 adjacent 2D networks are interpenetrated to show 2D + 2D → 3D parallel interpenetration of slabs. Furthermore, it is noteworthy that the oxidation of CoII to CoIII occurred in the preparation of 1 to give rise to a mixed‐valent cobalt coordination polymer, which can be confirmed by magnetic measurement. Magnetic property of 1 and luminescence of 2 were investigated.
Observations of evidence-based medicine in general practice
Authors: Zwolsman Sandra E. , Van Dijk Nynke , De Waard Margreet Wieringa
Published: September 2013

No objective measures are available for assessing the practice of evidence-based
medicine (EBM) in general practitioner (GP) trainees, as there is no description of the
EBM behaviour that is expected from trainees. As a first step to do so, we aimed to
identify which expressions of EBM (defined as the integration of evidence, clinical
experience and patient situation) can be observed in daily GP practice. Secondly, we
aimed to identify which considerations GPs had regarding EBM but did not share with the
patient during consultations. We performed a qualitative study, in which GPs were
observed during and interviewed after clinical consultations, with a focus on
expressions and considerations related to EBM during clinical decision-making. We
observed 147 consultations by 34 GPs (17 trainers and 17 trainees). EBM behaviour was
rarely visible in GPs’ decision-making. When interviewing the GPs, we found that aspects
of EBM that played a role in decision-making were not discussed with the patient.
Explicit consideration of all aspects of EBM would make EBM measurable and GPs more
aware of the foundations of their decisions. EBM behaviour is difficult to observe
during GP consultations and therefore cannot be assessed through observations
alone.
RETRACTED: Titrated oral misoprostol solution versus vaginal misoprostol for labor induction
Authors: Souza Alex S.R. , Feitosa Francisco E.L. , Costa Aurélio A.R. , Pereira Ana P.R. , Carvalho Andreza S. , Paixão Renata M. , Katz Leila , Amorim Melania M.R.
Published: September 2013

Objective

To determine the efficacy and safety of a titrated oral misoprostol solution compared with vaginal misoprostol tablets for labor induction.

Methods

A randomized, triple‐blind, multicenter clinical trial was conducted between March 2010 and June 2011. Women with a single gestation (n = 200) were randomized to receive a titrated oral misoprostol solution (initial misoprostol dose 20 μg/hour; dose increased by 20 μg/hour every 6 hours up to 80 μg/hour for a maximum of 48 doses) or vaginal misoprostol tablets (25 μg of misoprostol every 6 hours for a maximum of 8 doses). Risk ratios (RR) and 95% confidence intervals (CIs) were calculated for maternal and perinatal outcomes.

Results

The frequencies of vaginal delivery not achieved within 12 hours (RR 0.87; 95% CI, 0.62–1.22) and within 24 hours (RR 1.11; 95% CI, 0.83–1.49) were similar in the 2 groups. No differences were found in terms of uterine hyperstimulation, unfavorable cervix at 12 and 24 hours, oxytocin augmentation, tachysystole, epidural analgesia, adverse effects, and perinatal outcome. Approximately 70% of the women preferred the oral solution.

Conclusion

A titrated oral misoprostol solution was as effective and safe for labor induction as vaginal misoprostol tablets.

ClinicalTrial.gov: NCT00 992524
The conventional management of male infertility
Authors: Nieschlag Eberhard , Lenzi Andrea
Published: September 2013

Although the male reproductive function is impaired in about half of infertile couples, the evaluation of male infertility is underrated or neglected even today. In addition to a physical examination and imaging techniques, semen analysis as well as endocrine and genetic analyses should be part of the routine investigation. Few disorders have become subjects of rational treatment of the infertile male, even though, as examples, hypogonadotropic hypogonadism is treatable by gonadotropins and obstructive azoospermia by reconstructive surgery. Early treatment of maldescended testes and sexually transmitted diseases can prevent infertility. Similar pregnancy rates from patients with varicocele following surgery or counseling demonstrate the important role of the physician in the treatment of infertility. In the age of evidence‐based medicine, most empirical treatments have been demonstrated to be ineffective. Instead, symptomatic treatment by assisted reproductive techniques has become a central tool to overcome otherwise untreatable male infertility.
Orangism, Patriotism, and Slavery in Curaçao, 1795–1796
Authors: Fatah-Black Karwan
Published: September 2013

The defeat of the Dutch armies by the French and the founding of the Batavian Republic in 1795 created confusion in the colonies and on overseas naval vessels about who was in power. The Stadtholder fled to England and ordered troops and colonial governments to surrender to the British, while the Batavian government demanded that they abjure the oath to the Stadtholder. The ensuing confusion gave those on board Dutch naval vessels overseas, and in its colonies, an opportunity to be actively involved in deciding which side they wished to be on. This article adds the mutinies on board theCeresandMedeato the interplay between the Curaçao slave revolt of 1795 and the rise of the Curaçaoan Patriot movement in 1796. The mariners independently partook in the battle for the political direction of the island and debated which side they wished to be on in the fight between the French Revolution and the British Empire.
Mutiny and Maritime Radicalism in the Age of Revolution: An Introduction
Authors: Frykman Niklas , Anderson Clare , Heerma van Voss Lex , Rediker Marcus
Published: September 2013

The essays collected in this volume demonstrate that during the age of revolution (1760s–1840s) most sectors of the maritime industries experienced higher levels of unrest than is usually recognized. Ranging across global contexts including the Atlantic, Indian, and Pacific Oceans as well as the Caribbean, Andaman, and South China Seas, and exploring the actions of sailors, laborers, convicts, and slaves, this collection offers a fresh, sea-centered way of seeing the confluence between space, agency, and political economy during this crucial period. In this introduction we contend that the radicalism of the age of revolution can best be viewed as a geographically connected process, and that the maritime world was central to its multiple eruptions and global character. Mutiny therefore can be seen as part of something bigger and broader: what we have chosen to call maritime radicalism, a term as well as a concept that has had virtually no presence in the literature on the revolutionary era until now.
Dating the Death of Jesus: Memory and the Religious Imagination
Authors: Bond Helen K.
Published: September 2013

After discussing the scholarly preference for dating Jesus' crucifixion to 7 April 30 CE, this article argues that the precise date can no longer be recovered. All we can claim with any degree of historical certainty is that Jesus died some time around Passover (perhaps a week or so before the feast) between 29 and 34 CE. The emergence of the Johannine tradition (in which Jesus died on the day of Preparation) and the Markan tradition (in which Jesus died on the Passover itself) are explored through the lens of social/collective memory.
Papyrus 32 (Titus) as a Multi-text Codex: A New Reconstruction
Authors: Gathergood Emily
Published: September 2013

Following the recent emphasis on studying early Christian manuscripts as historical artefacts, whose textandmeta-textual aspects comprise important embodiments of reception and interpretation, this article re-examines the early Titus fragment 𝔓32(P.Ryl. Gr. 1.5) with respect to its physical situation within the manuscript. I expand the scope of current reconstructions to consider in detail the lost beginning of the epistle, and argue that Titus was not the first document in the codex: at least one other preceded. Although the identity of the accompanying material cannot be deduced codicologically, patristic evidence suggests that Titus was normally transmitted in a collection of thirteen or fourteen Pauline epistles when the 𝔓32codex was produced, rendering these the prime candidates.
Improving Adherence in Adolescent Chronic Kidney Disease: A Dialectical Behavior Therapy (DBT) Feasibility Trial
Authors: Hashim Becky L. , Vadnais Majorie , Miller Alec L.
Published: September 2013

Adolescents with chronic kidney disease often engage in nonadherent behaviors and have poorer outcomes. Dialectical behavior therapy (DBT) promotes quality-of-life improvement, with specific focus on “treatment-interfering behaviors” such as nonadherence. DBT has demonstrated effectiveness with patients who are otherwise difficult to reach, treat, and manage in outpatient settings. This study describes a DBT adaptation for improving adherence in adolescent patients with end-stage renal disease (ESRD). Seven adolescents with ESRD were enrolled in a 9-session DBT program. Process (illness acceptance) and outcome (quality of life, depression) measures were conducted pre- and posttreatment. Transplant team reports of adherence and health improvements were conducted at pre-, mid-, and posttreatment. Significant improvements were evident at posttreatment for depression and adherence. Findings suggest that DBT may promote adherence in difficult-to-treat youth with chronic illness.
Generalized bacterial genome editing using mobile group II introns and Cre‐lox
Authors: Enyeart Peter J , Chirieleison Steven M , Dao Mai N , Perutka Jiri , Quandt Erik M , Yao Jun , Whitt Jacob T , Keatinge‐Clay Adrian T , Lambowitz Alan M , Ellington Andrew D
Published: September 2013

Efficient bacterial genetic engineering approaches with broad‐host applicability are rare. We combine two systems, mobile group II introns (‘targetrons’) and Cre/lox, which function efficiently in many different organisms, into a versatile platform we call GETR (Genome Editing via Targetrons and Recombinases). The introns deliver lox sites to specific genomic loci, enabling genomic manipulations. Efficiency is enhanced by adding flexibility to the RNA hairpins formed by the lox sites. We use the system for insertions, deletions, inversions, and one‐step cut‐and‐paste operations. We demonstrate insertion of a 12‐kb polyketide synthase operon into the lacZ gene of Escherichia coli, multiple simultaneous and sequential deletions of up to 120 kb in E. coli and Staphylococcus aureus, inversions of up to 1.2 Mb in E. coli and Bacillus subtilis, and one‐step cut‐and‐pastes for translocating 120 kb of genomic sequence to a site 1.5 Mb away. We also demonstrate the simultaneous delivery of lox sites into multiple loci in the Shewanella oneidensis genome. No selectable markers need to be placed in the genome, and the efficiency of Cre‐mediated manipulations typically approaches 100%.
All-carbon sp-sp2 hybrid structures: Geometrical properties, current rectification and current amplification
Authors: Zhang Zhenhua , Zhang Junjun , Kwong Gordon , Li Ji , Fan Zhiqiang , Deng Xiaoqing , Tang Guiping
Published: September 2013

All-carbon sp-sp2 hybrid structures comprised of a zigzag-edged trigonal graphene (ZTG)and carbon chains are proposed and constructed as nanojunctions. It has been found that such simple hybrid structures possess very intriguing propertiesapp:addword:intriguing. The high-performance rectifying behaviors similar to macroscopic p-n junction diodes, such as a nearly linear positive-bias I-V curve (metallic behavior), a very small leakage current under negative bias (insulating behavior), a rather low threshold voltage and a large bias region contributed to a rectification, can be predicted. And also, a transistor can be built by such a hybrid structure, which can show an extremely high current amplification. This is because a sp-hybrid carbon chain has a special electronic structure which can limit the electronic resonant tunneling of the ZTG to a unique and favorable situation. These results suggest that these hybrid structures might promise importantly potential applications for developing nano-scale integrated circuits.
DNA methylation in interleukin-11 predicts clinical response to antidepressants in GENDEP
Authors: Powell T R , Smith R G , Hackinger S , Schalkwyk L C , Uher R , McGuffin P , Mill J , Tansey K E
Published: September 2013

Transcriptional differences in interleukin-11 (IL11) after antidepressant treatment have been found to correspond to clinical response in major depressive disorder (MDD) patients. Expression differences were partly mediated by a single-nucleotide polymorphism (rs1126757), identified as a predictor of antidepressant response as part of a genome-wide association study. Here we attempt to identify whether DNA methylation, another baseline factor known to affect transcription factor binding, might also predict antidepressant response, using samples collected from the Genome-based Therapeutic Drugs for Depression project (GENDEP). DNA samples from 113 MDD individuals from the GENDEP project, who were treated with either escitalopram (n=80) or nortriptyline (n=33) for 12 weeks, were randomly selected. Percentage change in Montgomery–Åsberg Depression Rating Scale scores between baseline and week 12 were utilized as our measure of antidepressant response. The Sequenom EpiTYPER platform was used to assess DNA methylation across the only CpG island located in the IL11 gene. Regression analyses were then used to explore the relationship between CpG unit methylation and antidepressant response. We identified a CpG unit predictor of general antidepressant response, a drug by CpG unit interaction predictor of response, and a CpG unit by rs1126757 interaction predictor of antidepressant response. The current study is the first to investigate the potential utility of pharmaco-epigenetic biomarkers for the prediction of antidepressant response. Our results suggest that DNA methylation in IL11 might be useful in identifying those patients likely to respond to antidepressants, and if so, the best drug suited to each individual.
Reversible photocontrol of self-assembled peptide hydrogel viscoelasticity
Authors: Doran Todd M. , Ryan Derek M. , Nilsson Bradley L.
Published: September 2013

Peptide hydrogels are promising biomaterials for applications ranging from drug delivery to tissue engineering.
Relay selection with outdated channel state information in cooperative communication systems
Authors: Fei Li , Gao Qiang , Zhang Jun , Xu Qifeng
Published: September 2013

Relay selection has been considered as an effective method to improve the performance of cooperative communication. However, the channel state information (CSI) used in relay selection can be outdated, yielding severe performance degradation of cooperative communication systems. In this study, the authors investigate how to select relays under outdated CSI in an amplify‐and‐forward cooperative communication system to improve its outage performance. The authors adopt maximum a posteriori (MAP) estimation to predict the actual signal‐to‐noise ratio (SNR) of each relay during data transmission and propose a single‐relay selection (SRS) strategy based on the MAP estimation (SRS‐MAP). To reduce the computational complexity, we approximate the a posteriori probability density of SNR and obtain a closed form of the predicted SNR. Simulation shows that SRS‐MAP outperforms the relay selection strategies given in the literature. In order to further improve the outage performance, a new multiple‐relay selection (MRS) method for outdated CSI is proposed, and by applying it to existing SRS strategies the corresponding MRS strategies are obtained. The authors find that the MRS strategies perform much better than their corresponding SRS ones and the MRS method improves the outage performance of cooperative communication system more effectively under outdated CSI than under non‐outdated CSI.
Recognition of single and multiple partial discharge sources in transformers based on ultra‐high frequency signals
Authors: Sinaga Herman H. , Phung B.T. , Blackburn Trevor R.
Published: September 2013

Partial discharge (PD) is a symptom of insulation defect or degradation in high‐voltage equipment. Thus, PD detection is an important diagnostic tool. Furthermore in practical situations, the PD can be generated from a single or multiple sources. Being able to detect and classify such PD events will help to determine the necessary corrective action to prevent insulation breakdown. To demonstrate, three different simulated discharge conditions in transformers were investigated: void, floating metal and their combination. The PD signals were captured using an ultra‐high frequency (UHF) sensor and denoised using wavelet transform method by application of Matlab wavelet multi‐variate denoising tool. Two types of mother wavelet, that is, db and sym, were applied to decompose the signals and extract the signal features in terms of their skewness, kurtosis and energy. These features were then used as input to train a neural network to analyse and determine the PD source type. Results show this technique is able to classify and recognise single and multiple PD source types with a high degree of success.
Network usage determination using a transformer analogy
Authors: Abdelkader Sobhy M. , Morrow David John , Conejo Antonio J.
Published: September 2013

This study presents a new method for determining the transmission network usage by loads and generators, which can then be used for transmission cost/loss allocation in an explainable and justifiable manner. The proposed method is based on solid physical grounds and circuit theory. It relies on dividing the currents through the network into two components; the first one is attributed to power flows from generators to loads, whereas the second one is because of the generators only. Unlike almost all the available methods, the proposed method is assumption free and hence it is more accurate than similar methods even those having some physical basis. The proposed method is validated through a transformer analogy, and theoretical derivations. The method is verified through application to the IEEE 30 bus system and the IEEE 118 test system. The results obtained verified many desirable features of the proposed method. Being more accurate in determining the network usage, in an explainable transparent manner, and in giving accurate cost signals, indicating the best locations to add loads and generation, are among the many desirable features.
Reliability‐based phasor measurement unit placement in power systems considering transmission line outages and channel limits
Authors: Gomez Oscar , Rios Mario A. , Anders George
Published: September 2013

Since phasor measurement unit (PMU) was invented, there has been growing interest in developing methodologies for finding the minimum number of PMUs for complete system observability. The methods for the PMU placement must consider the fact that the network topology may change when the power system is affected by a contingency event. Therefore the PMU placement problem can be stated as finding the minimum number of PMUs for complete system observability considering the failure probability of transmission lines. In this study, the authors propose a new reliability‐ based model for the contingency constrained PMUs placement. Initially, a methodology, that considers the probability of failure of the power system components, is proposed. Next, an algorithm is presented for selecting the minimal number of PMUs and their locations to monitor the system under normal operation and the most credible contingencies. A probabilistic index is introduced to select a desired level of reliability for the wide‐area monitoring system. Finally, the availability of PMU measuring channels is incorporated in the model, so more realistic and useful results can be obtained. The problem is formulated and solved as a binary integer linear programming model and tested on the IEEE 9‐bus, IEEE 57‐bus and RTS96 test systems.
Selective resonant interaction between confined excitons and folded acoustic phonons in GaAs/AlAs multi-quantum wells
Authors: Jusserand B.
Published: September 2013

We demonstrate strongly resonant selective interaction between confined excitons and folded acoustic phonons in multi-quantum wells and quantitatively reproduce each scattered spectrum based on the resonant interaction with a single periodized confined exciton. We emphasize the possible impact of these resonances on the generation and detection functions in picosecond acoustics on semiconductor multilayers.
The effects of cold rolling on the microstructural and spall response of 1100 aluminum
Authors: Williams C. L. , Chen C. Q. , Ramesh K. T. , Dandekar D. P.
Published: September 2013

As received 1100-O aluminum was cold rolled (CR) to 30%, 70%, and 80% reduction, respectively, to study the effects of microstructural evolution on the spall response using plate impact experiments. Previous results show a sharp increase in pullback velocity for 1100-O aluminum with increase in peak shock stress between 4.0 and 8.3 GPa due to hardening, followed by a decrease for peak shock stresses up to 12.0 GPa possibly due to softening. This maximum was not observed for the 30% CR, which showed only an increase in pullback velocity over the shock stress range of 4.0–12.0 GPa due to hardening (net increase in dislocation density). For the 70% CR aluminum, no change was observed in the pullback velocity over the range tested (4.0–11.0 GPa) probably due to saturation in dislocation density. Similar observations were made for the 80% CR, that is, no change was observed in the spall response between 4.0 GPa and 11.0 GPa. However, variations were observed in the spall response for the 80% CR, and these variations are attributed to material inhomogeneity possibly caused by increased cold rolling beyond saturation. The results also show a significant increase in Hugoniot Elastic Limit with increase in percent cold rolling.
Efficient self-consistent treatment of electron correlation within the random phase approximation
Authors: Bleiziffer Patrick , Heßelmann Andreas , Görling Andreas
Published: September 2013

A self-consistent Kohn-Sham (KS) method is presented that treats correlation on the basis of the adiabatic-connection dissipation-fluctuation theorem employing the direct random phase approximation (dRPA), i.e., taking into account only the Coulomb kernel while neglecting the exchange-correlation kernel in the calculation of the Kohn-Sham correlation energy and potential. The method, denoted self-consistent dRPA method, furthermore treats exactly the exchange energy and the local multiplicative KS exchange potential. It uses Gaussian basis sets, is reasonably efficient, exhibiting a scaling of the computational effort with the forth power of the system size, and thus is generally applicable to molecules. The resulting dRPA correlation potentials in contrast to common approximate correlation potentials are in good agreement with exact reference potentials. The negatives of the eigenvalues of the highest occupied molecular orbitals are found to be in good agreement with experimental ionization potentials. Total energies from self-consistent dRPA calculations, as expected, are even poorer than non-self-consistent dRPA total energies and dRPA reaction and non-covalent binding energies do not significantly benefit from self-consistency. On the other hand, energies obtained with a recently introduced adiabatic-connection dissipation-fluctuation approach (EXXRPA+, exact-exchange random phase approximation) that takes into account, besides the Coulomb kernel, also the exact frequency-dependent exchange kernel are significantly improved if evaluated with orbitals obtained from a self-consistent dRPA calculation instead of an exact exchange-only calculation. Total energies, reaction energies, and noncovalent binding energies obtained in this way are of the same quality as those of high-level quantum chemistry methods, like the coupled cluster singles doubles method which is computationally more demanding.
CO2 laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements
Authors: Bamford D. J. , Cummings E. A. , Panasenko D. , Fenner D. B. , Hensley J. M. , Boivin R. L. , Carlstrom T. N. , Van Zeeland M. A.
Published: September 2013

A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 1017 m−2 in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.
A pair natural orbital implementation of the coupled cluster model CC2 for excitation energies
Authors: Helmich Benjamin , Hättig Christof
Published: September 2013

We demonstrate how to extend the pair natural orbital (PNO) methodology for excited states, presented in a previous work for the perturbative doubles correction to configuration interaction singles (CIS(D)), to iterative coupled cluster methods such as the approximate singles and doubles model CC2. The original \documentclass[12pt]{minimal}\begin{document}$\mathcal {O}(\mathcal {N}^5)$\end{document}O(N5) scaling of the PNO construction is reduced by using orbital-specific virtuals (OSVs) as an intermediate step without spoiling the initial accuracy of the PNO method. Furthermore, a slower error convergence for charge-transfer states is analyzed and resolved by a numerical Laplace transformation during the PNO construction, so that an equally accurate treatment of local and charge-transfer excitations is achieved. With state-specific truncated PNO expansions, the eigenvalue problem is solved by combining the Davidson algorithm with deflation to project out roots that have already been determined and an automated refresh with a generation of new PNOs to achieve self-consistency of the PNO space. For a large test set, we found that truncation errors for PNO-CC2 excitation energies are only slightly larger than for PNO-CIS(D). The computational efficiency of PNO-CC2 is demonstrated for a large organic dye, where a reduction of the doubles space by a factor of more than 1000 is obtained compared to the canonical calculation. A compression of the doubles space by a factor 30 is achieved by a unified OSV space only. Moreover, calculations with the still preliminary PNO-CC2 implementation on a series of glycine oligomers revealed an early break even point with a canonical RI-CC2 implementation between 100 and 300 basis functions.
Morphological stability of oxygen- and nitrogen-covered Ru$(11\bar 21)$(112¯1)
Authors: Shen Quantong , Chen Wenhua , Wang Hao , Bartynski Robert A.
Published: September 2013

Morphological stability of the atomically rough Ru$(11\bar 21)$(112¯1) surface upon annealing in NO2, O2, and NH3 at elevated temperatures has been studied using scanning tunneling microscopy (STM), low energy electron diffraction (LEED), and Auger electron spectroscopy. The surface becomes fully faceted and covered by oxygen after annealing at T ≥ 600 K in NO2 (10−8 Torr) or O2 (10−6 Torr). The LEED and STM studies reveal that the faceted surface consists of nanoscale ridges, exposing four facets $(10\bar 11)$(101¯1), $(01\bar 11)$(011¯1), $(10\bar 10)$(101¯0), and $(01\bar 10)$(011¯0) on the ridges, and the ridge size grows as the annealing temperature increases. Details of the facet structures and reconstructions have been observed. However, no evidence is found for faceting of Ru$(11\bar 21)$(112¯1) to occur upon annealing in NH3. Our findings should be important for development of Ru-based catalysts under oxygen-rich conditions.
Improved coarse-grained model for molecular-dynamics simulations of water nucleation
Authors: Zipoli Federico , Laino Teodoro , Stolz Steffen , Martin Elyette , Winkelmann Christoph , Curioni Alessandro
Published: September 2013

We developed a new coarse-grained (CG) model for water to study nucleation of droplets from the vapor phase. The resulting potential has a more flexible functional form and a longer range cutoff compared to other CG potentials available for water. This allowed us to extend the range of applicability of coarse-grained techniques to nucleation phenomena. By improving the description of the interactions between water molecules in the gas phase, we obtained CG model that gives similar results than the all-atom (AA) TIP4P model but at a lower computational cost. In this work we present the validation of the potential and its application to the study of nucleation of water droplets from the supersaturated vapor phase via molecular-dynamics simulations. The computed nucleation rates at T = 320 K and 350 K at different supersaturations, ranging from 5 to 15, compare very well with AA TIP4P simulations and show the right dependence on the temperature compared with available experimental data. To help comparison with the experiments, we explored in detail the different ways to control the temperature and the effects on nucleation.
Elastic moduli and hardness of highly incompressible platinum perpnictide PtAs2
Authors: Tschauner Oliver , Kiefer Boris , Tetard Florent , Tait Kimberly , Bourguille Judith , Zerr Andreas , Dera Przemyslaw , McDowell Alastair , Knight Jason , Clark Simon
Published: September 2013

PtAs2 appears to be the least compressible known arsenide with a bulk modulus of 220(5) GPa and a shear modulus of between 64 and 77 GPa. PtAs2 has a hardness of 11(1) GPa, which is remarkably high for an arsenide. These elastic and mechanical properties in combination with the known chemical inertness and the small indirect band gap add interest to the use and occurrence of PtAs2 at Pt-GaAs contacts in transistors. We note the modest fracture toughness of 1.1–1.6 MPa m1/2 of PtAs2.
Magnetic flux amplification by Lenz lenses
Authors: Schoenmaker J. , Pirota K. R. , Teixeira J. C.
Published: September 2013

Tailoring magnetic flux distribution is highly desirable in a wide range of applications such as magnetic sensors and biomedicine. In this paper we study the manipulation of induced currents in passive devices in order to engineer the distribution of magnetic flux intensity in a given region. We propose two different approaches, one based on especially designed wire loops (Lenz law) and the other based on solid conductive pieces (eddy currents). The gain of such devices is mainly determined by geometry giving perspective of high amplification. We consistently modeled, simulated, and executed the proposed devices. Doubled magnetic flux intensity is demonstrated experimentally for a moderate aspect ratio.
Design and characterization of a nano-Newton resolution thrust stand
Authors: Soni J. , Roy S.
Published: September 2013

The paper describes the design, calibration, and characterization of a thrust stand capable of nano-Newton resolution. A low uncertainty calibration method is proposed and demonstrated. A passive eddy current based damper, which is non-contact and vacuum compatible, is employed. Signal analysis techniques are used to perform noise characterization, and potential sources are identified. Calibrated system noise floor suggests thrust measurement resolution of the order of 10 nN is feasible under laboratory conditions. Force measurement from this balance for a standard macroscale dielectric barrier discharge (DBD) plasma actuator is benchmarked with a commercial precision balance of 9.8 μN resolution and is found to be in good agreement. Published results of a microscale DBD plasma actuator force measurement and low pressure characterization of conventional plasma actuators are presented for completeness.
Unconventional minimal subtraction and Bogoliubov-Parasyuk-Hepp-Zimmermann method: Massive scalar theory and critical exponents
Authors: Carvalho Paulo R. S. , Leite Marcelo M.
Published: September 2013

We introduce a simpler although unconventional minimal subtraction renormalization procedure in the case of a massive scalar λϕ4 theory in Euclidean space using dimensional regularization. We show that this method is very similar to its counterpart in massless field theory. In particular, the choice of using the bare mass at higher perturbative order instead of employing its tree-level counterpart eliminates all tadpole insertions at that order. As an application, we compute diagrammatically the critical exponents η and ν at least up to two loops. We perform an explicit comparison with the Bogoliubov-Parasyuk-Hepp-Zimmermann (BPHZ) method at the same loop order, show that the proposed method requires fewer diagrams and establish a connection between the two approaches.
Note: Continuous-wave time-of-flight laser scanner using two laser diodes to avoid 2π ambiguity
Authors: Hwang Sungui , Jang Junhwan , Park Kyihwan
Published: September 2013

In the continuous-wave time-of-flight method, the distance traveled by light can be obtained by using the phase difference between the reference signal and the measured signal. However, when the phase difference exceeds 2π, the distance cannot be differentiated because the distance variation repeats every 2π period. In this paper, we propose a method in which low- and high-frequency signals are separately applied to two laser diodes simultaneously, and processed using two different signal processing circuits to solve the 2π ambiguity problem and achieve a high distance resolution for a longer distance measurement.
Force-field calculation and geometry of the HOOO radical
Authors: Suma Kohsuke , Sumiyoshi Yoshihiro , Endo Yasuki
Published: September 2013

High-level ab initio calculations using the Davidson-corrected multireference configuration interaction (MRCI) level of theory with Dunning's correlation consistent basis sets and force-field calculations were performed for the HOOO radical. The harmonic vibrational frequencies and their anharmonic constants obtained by the force-field calculations reproduce the IR-UV experimental vibrational frequencies with errors less than 19 cm−1. The rotational constants for the ground vibrational state obtained using the vibration–rotation interaction constants of the force-field calculations also reproduce the experimentally determined rotational constants with errors less than 0.9%, indicating that the present quantum chemical calculations and the derived spectroscopic constants have high accuracy. The equilibrium structure was determined from the experimentally determined rotational constants combined with the theoretically derived vibration–rotation interaction constants. The determined geometrical parameters agree well with the results of the present MRCI calculation.
Capacitance-voltage characterization of interfaces between positive valence band offset dielectrics and wide bandgap semiconductors
Authors: Yeluri Ramya , Liu Xiang , Swenson Brian L. , Lu Jing , Keller Stacia , Mishra Umesh K.
Published: September 2013

A photo-assisted capacitance voltage (C-V) characterization technique for interfaces between positive valence band offset dielectrics (Al2O3, SiO2) and wide bandgap semiconductors is presented. It is shown that the valence band barrier for holes at the interface affects the measurement and a method to extract border trap and interface state density values from the measured C-V curves is suggested. Dielectric-semiconductor interface characterization has been well studied for silicon but the characterization techniques are not transferable to wide bandgap semiconductors, such as GaN and SiC, due to the low minority carrier generation rate. Multiple dielectrics deposited by various techniques have been employed in these devices; but in order to ascertain the most suitable dielectric, an effective characterization technique that works well with dielectrics on wide-bandgap semiconductors is required.
Study of Au/Hg3In2Te6 interface by synchrotron radiation photoemission spectroscopy
Authors: Sun Jie , Fu Li , Wang Yiyi , Ren Jie , Li Yapeng , Zhang Wenhua , Zhu Junfa
Published: September 2013

The Au/Hg3In2Te6 interface was systematically investigated by synchrotron radiation photoemission spectroscopy (SRPES). Before the Au film prepared, the effects of the Ar+ ion etching process on elements and chemical bonding of the Hg3In2Te6 surface were studied first. The electronic structure and chemical reaction at the interface region with Au coverage ranging from 0.37 to 25 monolayers (ML) were also studied by exciting Te 4d, In 4d, and Au 4f core levels, respectively. Meanwhile, the growth mode of Au at MIT surface was confirmed to be the Volmer-Weber (VW) mode through the attenuation of Te 4d and In 4d core level signal strength. Moreover, chemical reactions between Au and Te with the product of AuTe2 were found at the Au/Hg3In2Te6 interface when Au deposition reached 0.72 ML. In addition, through the decomposition of Te 4d core level peaks at 25 ML of Au deposition, a re-bonding process of Hg-Te was found at the interface area. Finally, the interface formation process was summarized in detail.
Erratum: “On Lie systems and Kummer–Schwarz equations” [J. Math. Phys. 54, 033505 (2013)]
Authors: de Lucas J. , Sardón C.
Published: September 2013

We show that several types of the so-called generalised Kummer–Schwarz equations cannot be treated through a Lie system in the way described in our work “On Lie systems and Kummer–Schwarz equations.”
Heterodyne and subharmonic mixing at 0.6 THz in an AlGaAs/InGaAs/AlGaAs heterostructure field effect transistor
Authors: Giliberti Valeria , Di Gaspare Alessandra , Giovine Ennio , Boppel Sebastian , Lisauskas Alvydas , Roskos Hartmut G. , Ortolani Michele
Published: September 2013

We fabricated a two-dimensional-electron-gas field effect transistor with an asymmetric terahertz antenna connected to the channel terminals and a gate length of 1 μm. We investigated frequency mixing in the transistor's channel by measuring, with a quasi-optical setup, the heterodyne, second- and third-order subharmonic mixing signal at 0.592 THz. The dependence on the gate voltage and on the radiation power of both the local-oscillator and the radio-frequency signals was studied for all mixing orders. The conditions for full-plasmonic-mixing are fulfilled in our transistor at room temperature.
Detection of electromagnetic pulses produced by hypervelocity micro particle impact plasmas
Authors: Close Sigrid , Linscott Ivan , Lee Nicolas , Johnson Theresa , Strauss David , Goel Ashish , Fletcher Alexander , Lauben David , Srama Ralf , Mocker Anna , Bugiel Sebastian
Published: September 2013

Hypervelocity micro particles (mass < 1 ng), including meteoroids and space debris, routinely impact spacecraft and produce plasmas that are initially dense (∼1028 m−3), but rapidly expand into the surrounding vacuum. We report the detection of radio frequency (RF) emission associated with electromagnetic pulses (EMPs) from hypervelocity impacts of micro particles in ground-based experiments using micro particles that are 15 orders of magnitude less massive than previously observed. The EMP production is a stochastic process that is influenced by plasma turbulence such that the EMP detection rate that is strongly dependent on impact speed and on the electrical charge conditions at the impact surface. In particular, impacts of the fastest micro particles occurring under spacecraft charging conditions representative of high geomagnetic activity are the most likely to produce RF emission. This new phenomenon may provide a source for unexplained RF measurements on spacecraft charged to high potentials.
High power laser coupling to carbon nano-tubes and ion Coulomb explosion
Authors: K Magesh Kumar K , Tripathi V. K.
Published: September 2013

Linear and non linear interaction of laser with an array of carbon nanotubes is investigated. The ac conductivity of nanotubes, due to uneven response of free electrons in them to axial and transverse fields, is a tensor. The propagation constant for p-polarization shows resonance at a specific frequency that varies with the direction of laser propagation. It also shows surface plasmon resonance at ω=ωp/2, where ωp is the plasma frequency of free electrons inside a nanotube, assumed to be uniform plasma cylinder. The attenuation constant is also resonantly enhanced around these frequencies. At large laser amplitude, the nanotubes behave as thin plasma rods. As the electrons get heated, the nanotubes undergo hydrodynamic expansion. At an instant when plasma frequency reaches ωp=2ω, the electron temperature rises rapidly and then saturates. For a Gaussian laser beam, the heating rate is maximum on the laser axis and falls off with the distance r from the axis. When the excursion of the electrons Δ is comparable or larger than the radius of the nanotube rc, the nanotubes undergo ion Coulomb explosion. The distribution function of ions turns out to be a monotonically decreasing function of energy.
Hamiltonian magnetohydrodynamics: Lagrangian, Eulerian, and dynamically accessible stability—Theory
Authors: Andreussi T. , Morrison P. J. , Pegoraro F.
Published: September 2013

Stability conditions of magnetized plasma flows are obtained by exploiting the Hamiltonian structure of the magnetohydrodynamics (MHD) equations and, in particular, by using three kinds of energy principles. First, the Lagrangian variable energy principle is described and sufficient stability conditions are presented. Next, plasma flows are described in terms of Eulerian variables and the noncanonical Hamiltonian formulation of MHD is exploited. For symmetric equilibria, the energy-Casimir principle is expanded to second order and sufficient conditions for stability to symmetric perturbation are obtained. Then, dynamically accessible variations, i.e., variations that explicitly preserve invariants of the system, are introduced and the respective energy principle is considered. General criteria for stability are obtained, along with comparisons between the three different approaches.