bluuebunny/crossref_metadata_2025 huggingface dataset:
Atheism and the gift of death
Authors: BURLEY MIKEL
Published: March 2012

Richard Beardsmore once argued that, although it is possible for atheists and religious believers alike to regard life as a gift, the regarding of one's owndeathas a gift is open only to the (Christian) believer. I discuss this interesting contention, and argue that, notwithstanding some important differences between the attitudinal possibilities available to atheists and believers in God, there are at least three senses in which an atheist could regard death as a gift. Two of these involve death's being conceived as serving some particular purpose, whereas the third derives from a more pervasive affirmatory attitude to life as a whole.
FOG in GATS commitments – why WTO Members should care
Authors: ADLUNG RUDOLF , MORRISON PETER , ROY MARTIN , ZHANG WEIWEI
Published: March 2012

The entry into force of the General Agreement on Trade in Services in 1995 marked a new stage in the history of the multilateral system. Given the peculiarities of services trade, the Agreement contains a variety of conceptual innovations, including its extension to transactions (modes of supply), beyond conventional cross-border trade, and various types of non-tariff restrictions. In turn, the new concepts needed time to be absorbed by the ministries and agencies involved, many of which might have been surprised by ‘their’ sectors being covered by a trade agreement and the ensuing government-internal coordination needs. Thus, understandably, the schedules that emerged from the Uruguay Round, which still account for the majority of current commitments, contain a variety of ill-specified entries. Such entries undermine the transparency and predictability of market conditions, thereby affecting trade and investment decisions in services. Poorly specified commitments also give rise to trade disputes. While the scheduling conventions agreed for the Doha Round provided for technical refinements that would leave the substance of commitments unchanged, this possibility was used far more sparingly than could have been expected. Moreover, additional flaws would have been introduced if some of the (preliminary) offers had entered into effect. The following discussion tries to explain the scope for refinements and develop a clearer picture of the commitments warranting correction – whether in the form of a final Doha Round outcome or through negotiation-independent action by WTO Members.
How uncertainty about outside options impedes international cooperation
Authors: Urpelainen Johannes
Published: March 2012

International cooperation often requires costly policy adjustments. States may worry, however, that such adjustments weaken their outside options, and thus reduce their bargaining power. How does uncertainty about the effects of policy adjustments on outside options influence the depth of cooperation that states can achieve? My game-theoretic analysis shows that uncertainty about outside options is an obstacle to deep cooperation. If states agree on deep cooperation, they have to compensate vulnerable states with weak outside options for their losses. Under uncertainty, states that are not vulnerable have an incentive to falsely claim that they are vulnerable (i) to avoid a side payment or (ii) to obtain compensation for being vulnerable. The result holds even if the added value of deep cooperation would be large enough to fully compensate the losers. In equilibrium, the more vulnerable state sometimes offers a side payment to the less vulnerable one. More broadly, the analysis reveals a new international cooperation problem and provides a new rationale for costly signaling mechanisms and delegation to international organizations.
Revision of the actinopterygian genus Mimipiscis (=Mimia) from the Upper Devonian Gogo Formation of Western Australia and the interrelationships of the early Actinopterygii
Authors: Choo Brian
Published: March 2012

The Devonian actinopterygian Mimia Gardiner & Bartram (1977) of the Upper Devonian (Frasnian) Gogo Formation of Western Australia, one of the most completely known of all Palaeozoic ray-finned fishes, is renamed Mimipiscis nom. nov. due to preoccupation of the former genus by the butterfly Mimia Evans (1953). Recently acquired data, including the description of newly prepared fossil material, has revealed the presence of a second species in this formerly monotypic genus, as well as previously unreported features of the tail, parasphenoid and ontogenetic variability of type species, Mimipiscis toombsi (Gardiner & Bartram 1977). The second form, Mimipiscis bartrami sp. nov., differs from the contemporary M. toombsi in details of the body shape, squamation, snout, suboperculum and parasphenoid. Phylogenetic analyses recover Mimipiscis and Gogosardina as sister genera within a monophyletic Mimiidae, a clade restricted to the Late Devonian of Western Australia.
Wireless multi-gigabit data transmission using active MMIC components at 220 GHz
Authors: Antes Jochen , Lopez-Diaz Daniel , Tessmann Axel , Leuther Arnulf , Massler Hermann , Zwick Thomas , Ambacher Oliver , Kallfass Ingmar
Published: March 2012

In this paper we present a wireless data link for multi-gigabit transmission in the mmW frequency range. The link is realized using waveguide modules based on fully integrated 50 nm metamorphic high electron mobility transistor (mHEMT) transmit and receive millimeter wave monolithic integrated circuits (MMICs) and provides transmission of data rates up to 12.5 Gbit/s modulated on a 220 GHz carrier. The receiver input sensitivity is characterized down to values of −38.6 dBm and shows an error rate of 3.0 × 10−9. Measurements using a coherent link setup show bit error rates better than 1.6 × 10−9 for a data rate of 10 Gbit/s and a transmission distance of 2 m. For a distance of 20 m a real-time Digital Video Broadcasting – Satellite (DVB-S) television transmission is realized. The signal quality after the wireless link is sufficient for a commercial DVB-S receiver to display the television programs.
T‐cell receptor signaling and the pathogenesis of autoimmune arthritis: insights from mouse and man
Authors: Sakaguchi Shimon , Benham Helen , Cope Andrew P , Thomas Ranjeny
Published: March 2012

The immune system has evolved to survey and respond appropriately to the universe of foreign pathogens, while at the same time deploying an intricate repertoire of mechanisms that keep responses to host tissues in check. For the adaptive immune system, specificity and sensitivity are provided by a large repertoire of antigen T‐cell receptors (TCRs) constructed in their extracellular domain to recognize antigenic peptide fragments restricted and presented by histocompatibility complex molecules, and coupled through intracellular domains to signal transduction modules that serve to transmit environmental cues inside the cell. In this review we consider recent evidence that has provided insight into how altered TCR signaling thresholds could contribute to human autoimmune arthritis, including rheumatoid arthritis (RA), and the spondyloarthropathies (SpA). We also discuss mechanistic studies that demonstrate how perturbations of T‐cell antigen receptor signaling in the SKG mouse model can promote systemic autoimmunity and the intersection with essential innate immune pathways that lead to the development of chronic inflammatory phenotypes.
The Cancer Drawings of Catherine Arthur
Authors: Sebestyen Amanda
Published: March 2012

At the age of forty-eight Catherine Arthur gave up her job as a technical design journalist to go to Hornsey School of Art. Shortly after completing her course she discovered that she had breast cancer. Over the past year Catherine Arthur has composed a unique cycle of drawings, mythologizing the crisis in her body, reinterpreting ancient symbols as well as creating new ones of her own. This article is extended from a speech given at Lauderdale House in London for the opening of the exhibition Love and Pain: the cancer drawings and erotic drawings of Catherine Arthur’.
A Straight Playing Field or Queering the Pitch?: Centring Sexuality in Social Policy
Authors: Carabine Jean
Published: March 2012

This article argues that there is a lack of theorizing about sexuality within social policy in what is referred to as the mainstream and more surprisingly within feminist social policy. This is particularly surprising given the presence of sexuality in recent as well as past social policies as well as in social theory. The purpose of this article is not merely to argue that a relationship between sexuality and social policy should be examined but rather to explore and outline the specific nature of the relationship and its implications for both sexuality and the discipline of social policy. Specifically, how do prevalent sexuality discourses inform and constitute social policy and what are the social relations involved in this process? Correspondingly, what role does social policy play in constituting what we know to be the ‘truths’ of sexuality? What exclusions and inclusions result from these dominant social relations and discourses when ‘played’ through social policy?

That sexuality has failed to be analytically incorporated within the discipline of social policy is addressed. First, reasons for the lack of theorizing are explored. Specifically, the historical development of the discipline and the formation of an implicit consensus about what constitute the real concerns of welfare. Second, there is an examination of the ways feminist social policy has or has not engaged with sexuality. The final section posits an emergent framework for integrating sexuality into social policy analyses and critiques.
All Het Up!: Rescuing Heterosexuality on the Oprah Winfrey Show
Authors: Epstein Debbie , Steinberg Deborah Lynn
Published: March 2012

The Oprah Winfrey Show provides an interesting set of contradictions. On the one hand, it appears to challenge common-sense assumptions about relationships, specifically heterosexual relationships (for example, by consistently raising issues of sexual violence within a heterosexual context). Yet, at the same time, Oprah's presentation often works to reinforce precisely the norms she seeks to challenge. Through a close analysis of a selection of programme clips from one particular programme among many about relationships, sexuality and families, this article will consider the ways in which the Oprah Winfrey Show both problematizes and yet normalizes the boundaries of heterosexuality. Here we shall discuss both the resolute exposure and exploration of what could be termed the casualities of normative (and compulsory) heterosexuality and, paradoxically, its recuperation as a ‘rational’ ideal. In exploring the ways in which this recuperation takes place, we shall begin with a brief consideration of two of the key discourses which shape the show: the discourse of therapy and that of kinship. Our analysis of the sexual politics of the Oprah Winfrey Show in these terms will focus on the programme, ‘How to Make Love Last’ (18 January 1993). Like so many other programmes, ‘How to Make Love Last’ intends to highlight and deal with problems within heterosexual relationships as distressing but solvable (through the medium of therapeutic self-help). At another level, however, the programme also (unwittingly) reveals a different order of problems which, ironically, can only be reinforced by the mode of rescue proposed and staged.
The Curse of the Smile: Ambivalence and the ‘Asian’ Woman in Australian Multiculturalism
Authors: Ang Ien
Published: March 2012

This article critiques Australia's official discourse of multiculturalism, with its rhetoric of ‘celebrating cultural diversity’ and tolerance, by looking at the way in which this discourse suppresses the ambivalent positioning of ‘Asians’ in Australian social space. The discourse of multiculturalism and the official, economically motivated desire for Australia to become ‘part of Asia’ has resulted in a relatively positive valuation of ‘Asia’ and ‘Asians’, an inversion from the racist exclusionism of the past. Against the self-congratulatory stance of this discourse, this article signals the operation of ambivalence at two levels: at the structural level, insofar as it points to the inherent contradictions in the idea of the ‘multicultural nation’ and its fantasy of a harmonious ‘unity-in-diversity’, and at the subjective level, in the sense that the ethos of multiculturalism doesn't erase the ambivalent relations of acceptance/rejection between majority and minority subjects. Several instances of such ambivalence pertaining to the positioning and representation of the ‘Asian’ woman are given.
Warmth and Unity with all Women?
Authors: Murdolo Adele
Published: March 2012

In this paper I discuss the four Women and Labour conferences which were held in Australian capital cities over the seven years between 1978 and 1984. I explore the ways in which the history of Australian feminist activism during this period could be written, questioning in particular the claim that the Women and Labour conferences have been central to the history of Australian feminism. I discuss the ways in which a historical sense could be established, using writings about the conferences as historical ‘evidence’, that race and ethnic divisions between women had not been important to the ‘women's movement’ until 1984. In other words, I challenge the construction of this conference as a turning point – not only in the feminist politicization of immigrant and Aboriginal women, but also in the politicization of all feminists about race and ethnic divisions. More broadly, I am interested in how a history would be written if it aimed to get to the ‘truth’ about racism and about the feminist activism of immigrant women. How would the apparent lack of written ‘evidence’ – at least until 1984 – of immigrant women's feminist activism, and of the awareness of Australian feminists about issues of racism, be written into this history? In addition, I suggest that it is important to the writing of feminist history in Australia that published documentation has been mostly produced by anglo women, and is thus partial and mediated by the lived, embodied experiences of anglo women. Finally, my intention is to interrogate commonly understood narratives about Australian feminist history, to challenge their seamlessness, and to suggest the importance of recognizing the tension within feminist discourses between difference as benign diversity and difference as disruption.
Troubled Teens: Managing Disorders of Transition and Consumption
Authors: Griffin Christine
Published: March 2012

This article focuses on the representation of youth as a key moment of transition in contemporary western societies, set between the dependent state of childhood and the supposed maturity and independence of adult status. Young people are viewed as gendered, racialized and sexualized beings who also occupy specific class locations, and are assumed to move through crucial points of transition as they leave full-time education and enter the job market, as well as the (hetero)sexual and marriage marketplaces. The article examines some of the main discursive configurations and treatment regimes through which ‘troubled teens’ are constructed and managed, especially in relation to notions about disordered patterns of consumption and transition. The paper considers the moment of the ‘discovery’ of adolescence in the late nineteenth century, going on to examine young women's particular relationships to discourses around consumption in the contemporary British youth research literature, and to debates about ‘disrupted transitions’ and citizenship in the 1990s. The article ends with a brief examination of one approach to the ‘problem of troubled teens’ in the USA: Specialty Schools that offer a combination of educational, therapeutic and correctional regimes aimed at young people who have been identified in relation to various disorders of transition and consumption.
The Virtual Speculum in the New World Order
Authors: Haraway Donna J.
Published: March 2012

Beginning by reading a 1992 feminist appropriation of Michelangelo's Creation of Adam – in a cartoon in which the finger of a nude Adamic woman touches a computer keyboard, while the god-like VDT screen shows a disembodied fetus – ‘Virtual Speculum’ argues for a broader conception of ‘new reproductive technologies’ in order to foreground justice and freedom projects for differently situated women in the New World Order. Broadly conceptualized reproductive practices must be central to social theory in general, and to technoscience studies in particular. Tying together the politics of self help and women's health movements in the United States in the 1970s with positions on reproductive freedom articulated within the Legal Defense and Educational Fund of the NAACP in the 1990s, the paper examines recent work in feminist science studies in several disciplinary and activist locations. Statistical analysis and ethnography emerge as critical feminist technologies for producing convincing representations of the reproduction of inequality. Untangling the semiotic and political–economic dialectics of invisibility and hypervisibility, ‘Virtual Speculum’ concludes by linking the well-surveyed amniotic fluid of on-screen fetuses and the off-frame diarrhea of uncounted and underfed infants in regimes of flexible accumulation and structural adjustment.
Accurate evaluation of exchange fields in finite element micromagnetic solvers
Authors: Chang R. , Escobar M. A. , Li S. , Lubarda M. V. , Lomakin V.
Published: March 2012

Quadratic basis functions (QBFs) are implemented for solving the Landau-Lifshitz-Gilbert equation via the finite element method. This involves the introduction of a set of special testing functions compatible with the QBFs for evaluating the Laplacian operator. The results by using QBFs are significantly more accurate than those via linear basis functions. QBF approach leads to significantly more accurate results than conventionally used approaches based on linear basis functions. Importantly QBFs allow reducing the error of computing the exchange field by increasing the mesh density for structured and unstructured meshes. Numerical examples demonstrate the feasibility of the method.
Studies of sintered MRE-Fe-B magnets by DyF3 addition or diffusion treatment (MRE = Nd + Y + Dy)
Authors: Tang W. , Dennis K. W. , Kramer M. J. , Anderson I. E. , McCallum R. W.
Published: March 2012

Sintered MRE2(Fe, Co)14B magnets by DyF3 blending or diffusion treatment were investigated. “Base-line” magnets with a thickness of 1.5 mm were coated (painted) with DyF3 powder and heated to promote Dy diffusion at 800–900 °C, i.e., “Diffusion” magnets. For comparison, the magnet alloy powder for making Base-line magnets was blended with 3–5 wt.% DyF3 powder and then made into sintered magnets, i.e., “Blended” magnets. The coercivity and (BH)max of Base-line magnets were 9.7 kOe and 32.7 MGOe, respectively, while the coercivity of Diffusion magnets was increased to 15 kOe and the (BH)max was nearly unchanged at 31.4 MGOe. Blended magnets with 5 wt% DyF3 had a coercivity of 17.8 kOe, but the (BH)max was reduced to 25.4 MGOe, due to a considerable reduction of remanence. The total Dy concentration in the MRE2(Fe, Co)14B Diffusion magnets with a β value of −0.5%/°C was 5.3 wt%, while typical commercial Nd-based Nd2Fe14B magnets require at least 7.5 wt% Dy to achieve the same β. Therefore, the MRE2(Fe, Co)14B Diffusion magnets exhibited better temperature stability.
A quantum-mechanical relaxation model
Authors: Skomski R. , Kashyap A. , Sellmyer D. J.
Published: March 2012

The atomic origin of micromagnetic damping is investigated by developing and solving a quantum-mechanical relaxation model. A projection-operator technique is used to derive an analytical expression for the relaxation time as a function of the heat-bath and interaction parameters. The present findings are consistent with earlier research beyond the Landau-Lifshitz-Gilbert (LLG) equation and show that the underlying relaxation mechanism is very general. Zermelo’s recurrence paradox means that there is no true irreversibility in non-interacting nanoparticles, but the corresponding recurrence times are very long and can be ignored in many cases.
Current-induced domain wall motion in a multilayered nanowire for achieving high density bit
Authors: Komine T. , Ooba A. , Sugita R.
Published: March 2012

We herein propose a multilayered nanowire in order to achieve a high density bit or short bit length. The multilayered nanowire consists of a continuous layer and a granular layer which are coupled by interlayer exchange and magnetostatic interactions. The continuous layer has a role of data transfer based on current-induced domain wall motion (CIDWM). The granular layer has a role of stabilizing data, and the current flows only through the continuous layer. We demonstrate CIDWM in the multilayered nanowire by micromagnetic simulation. The domain wall width in the multilayered nanowire is narrower than that of the single-layer nanowire because of weak exchange coupling in the granular layer. As a result, the smaller bit length can be obtained in the multilayered nanowire. Moreover, the critical current density in the multilayered nanowire almost equals to the critical current density of the single-layer nanowire with the same domain wall width as that of the multilayered nanowire.
Magnetoplasmonic nanostructures based on nickel inverse opal slabs
Authors: Grunin A. A. , Sapoletova N. A. , Napolskii K. S. , Eliseev A. A. , Fedyanin A. A.
Published: March 2012

Nanostructured nickel surfaces representing periodically arranged spherical voids in a nickel film are obtained by electrochemical deposition through a self-assembled opaline template. Excitation of surface plasmon-polaritons (SPPs) on the surface of the sample is experimentally observed as the Wood’s anomaly in the reflectance spectra. Transversal magneto-optical Kerr effect (TMOKE) spectra are measured at the different angles of incidence and azimuthal angles. The two- to-threefold enhancement of TMOKE caused by the excitation of mixed plasmons in two selected azimuthal configurations is observed.
The magnetic and magnetocaloric properties of NdFe12−xMox compounds
Authors: Xia Yuanhua , Du Honglin , Xu Jianhui , Zhang Yan , Wang Changsheng , Han Jingzhi , Liu Shunquan , Xu Qing , Yang Jinbo
Published: March 2012

The crystal structure and magnetic properties of NdFe12−xMox (x = 2.25, 2.5, 2.75, 3.0) compounds were synthesized and investigated. These compounds crystallized in ThMn12-type single phase, and the Curie temperature decreased with increasing Mo content. NdFe9.5Mo2.5 has a Curie temperature around room temperature, and a reversible magnetic entropy change was observed ∼290 K due to the second-order magnetic transition. The maximum value of −ΔSM is 2.38 J kg-1 K-1 at 290 K for a magnetic field change of 50 kOe. The working temperature span is more than 150 K and the relative cooling power reaches 357 J/kg, which makes the compound a promising candidate for magnetic refrigerator vicinal room temperature.
Magnetic energy coupling system based on micro-electro-mechanical system coils
Authors: Li Xiuhan , Yuan Quan , Yang Tianyang , Liu Jian , Zhang Haixia
Published: March 2012

In this paper, a high efficiency wireless energy transfer system based on MEMS coils is first developed. The permanent magnetic core used in the transmitting coil can not only enhance the magnetic flux but also applies a strong and uniform magnetic field distribution around the core. Ansoft hfss is then used to analyze the performance of two coupling coils designed to be resonated at the same frequency. The distribution of magnetic field strength and coupling efficiency is modeled and characterized. High-performance bio-compatible MEMS coils were fabricated on a glass wafer by thick glue photolithography and electroplating technique. We measured a peak value of energy transfer at the resonant frequency of 23 MHz, and the coupling efficiency is higher than 10% within the distance of 10–20 cm by sweeping frequencies from 1 MHz to 200 MHz. Experiments also show that the resonant coupling efficiency is not much affected by the relative position of the two coils in a large range.
Noise-induced synchronization in spin torque nano oscillators
Authors: Nakada K. , Yakata S. , Kimura T.
Published: March 2012

We have numerically studied the stochastic magnetization dynamics of a pair of spin torque nano oscillators (STNOs) under noisy current injection by using the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation with a macro-spin approximation. Common noisy current injection into both STNOs is found to induce the phase synchronizations, where two STNOs show in-phase or anti-phase locked precession depending on the sequences of Gaussian white noise. The noise-induced synchronization could be a possible application for controlling the output power in the array of the STNOs.
Ultra-high coercivity small-grain FePt media for thermally assisted recording (invited)
Authors: Mosendz O. , Pisana S. , Reiner J. W. , Stipe B. , Weller D.
Published: March 2012

Thermally assisted magnetic recording (TAR), a promising approach to extend data storage densities beyond 1 terabit/in.2, requires high anisotropy granular magnetic media with small grains and a tight grain size distribution. We demonstrate sputtered chemically ordered granular L10 Fe45Pt45Ag10 media using carbon segregant on glass substrates. X-ray diffraction and transmission electron microscopy reveal high chemical ordering, an average grain size of 〈D〉 = 7.2 nm and a size distribution as low as σD/〈D〉=16%. Magnetic properties studied with a vibrating sample magnetometer show Hc = 4.8 T, Hk > 9 T, and Ku > 4.5 × 107 erg/cm3. Drag testing of this media shows recording areal densities of 620 Gb/in.2.
Performance evaluation and comparison of a novel “retro-fit” heat exchanger and a conventional solar water heater with a single coiled heat exchanger
Authors: Nchelatebe Nkwetta Dan , Smyth Mervyn
Published: March 2012

The performances of solar water heating systems have improved steadily over recent years due to improved component quality and design. Solar water heating systems in Northern Maritime climates, however, are still not viable economically. In order to make a significant impact on the domestic hot water heating market, solar water heaters must be innovative, cost-effective, and adaptable for retro-fit installation. This paper investigates experimentally the performance of a novel heat exchanger (the “Solasyphon”) designed and developed for external connection to an existing traditional single-coil hot water cylinder. The connection of the novel heat exchanger to an existing system reduces the cost of installation as it avoids the need to replace the existing single-coil hot water cylinder with a twin-coil system. However, the connection of this Solasyphon to a solar water heating system has negative effects on heat losses especially at higher temperatures based on the size of the solar collector. The experimentation was carried out under outdoor and indoor control operating conditions. This paper presents the monitored performance of the Solasyphon compared with that of a conventional solar water heater with a coiled heat exchanger and the negative effects regarding the heat losses resulting from the small size of the solar collector especially at high inlet temperatures (greater than 70 °C).
An in-vacuum x-ray diffraction microscope for use in the 0.7–2.9 keV range
Authors: Vine D. J. , Williams G. J. , Clark J. N. , Putkunz C. T. , Pfeifer M. A. , Legnini D. , Roehrig C. , Wrobel E. , Huwald E. , van Riessen G. , Abbey B. , Beetz T. , Irwin J. , Feser M. , Hornberger B. , McNulty I. , Nugent K. A. , Peele A. G.
Published: March 2012

A dedicated in-vacuum coherent x-ray diffraction microscope was installed at the 2-ID-B beamline of the Advanced Photon Source for use with 0.7–2.9 keV x-rays. The instrument can accommodate three common implementations of diffractive imaging; plane wave illumination; defocused-probe (Fresnel diffractive imaging) and scanning (ptychography) using either a pinhole, focused or defocused probe. The microscope design includes active feedback to limit motion of the optics with respect to the sample. Upper bounds on the relative optics-to-sample displacement have been measured to be 5.8 nm(v) and 4.4 nm(h) rms/h using capacitance micrometry and 27 nm/h using x-ray point projection imaging. The stability of the measurement platform and in-vacuum operation allows for long exposure times, high signal-to-noise and large dynamic range two-dimensional intensity measurements to be acquired. Finally, we illustrate the microscope's stability with a recent experimental result.
Polymer adsorption on a fractal substrate: Numerical study
Authors: Blavatska Viktoria , Janke Wolfhard
Published: March 2012

We study the adsorption of flexible polymer macromolecules on a percolation cluster, formed by a regular two-dimensional disordered lattice at critical concentration pc of attractive sites. The percolation cluster is characterized by a fractal dimension \documentclass[12pt]{minimal}\begin{document}$d_s^{p_c}=91/49$\end{document}dspc=91/49. The conformational properties of polymer chains grafted to such a fractal substrate are studied by means of the pruned-enriched Rosenbluth method. We find estimates for the surface crossover exponent governing the scaling of the adsorption energy in the vicinity of transition point, \documentclass[12pt]{minimal}\begin{document}$\phi _s^{p_c}=0.425\pm 0.009$\end{document}φspc=0.425±0.009, and for adsorption transition temperature, \documentclass[12pt]{minimal}\begin{document}$T_A^{p_c}=2.64\pm 0.02$\end{document}TApc=2.64±0.02. As expected, the adsorption is diminished when the fractal dimension of the substrate is smaller than that of a plain Euclidean surface. The universal size and shape characteristics of a typical spatial conformation which attains a polymer chain in the adsorbed state are analyzed as well.
Afterpulsing and instability in superconducting nanowire avalanche photodetectors
Authors: Marsili F. , Najafi F. , Dauler E. , Molnar R. J. , Berggren K. K.
Published: March 2012

We investigated the reset time of superconducting nanowire avalanche photodetectors (SNAPs) based on 30 nm wide nanowires. We studied the dependence of the reset time of SNAPs on the device inductance and discovered that SNAPs can provide a speed-up relative to superconducting nanowire single-photon detectors with the same area but with some limitations: (1) Reducing the series inductance of SNAPs (necessary for the avalanche formation) could result in the detectors operating in an unstable regime, (2) a trade-off exists between maximizing the bias current margin and minimizing the reset time of SNAPs, and (3) reducing the reset time of SNAPs below ∼1 ns resulted in afterpulsing.
Coherent to turbulence transition, enhanced flow and confinement in a simple toroidal plasma
Authors: Goud T. S. , Ganesh R. , Saxena Y. C. , Raju D. , Sathyanarayana K. , Mohandas K. K. , Chavda C.
Published: March 2012

In a simple toroidal plasma, self consistent poloidal flow generation at different toroidal fields is observed. On changing the magnitude of toroidal field, transition occurs in the nature of fluctuation from highly coherent modes at low magnetic field to a turbulent broadband spectrum at high field accompanied by significant improvement in the confinement. Interestingly, though the coherence is reduced with the increasing field, the fluctuation driven poloidal flux remains comparable. The observed increase in the densities on high field side with the increase in magnetic field is simultaneously accompanied by the enhanced net poloidal flow. The present work demonstrates that in a toroidal compressible plasma, an intimate relationship exists between the fluctuations, self consistently generated flows and enhanced confinement.
Vibrationally resolved photoionization of N2 near threshold
Authors: O’Keeffe P. , Bolognesi P. , Moise A. , Richter R. , Ovcharenko Y. , Avaldi L.
Published: March 2012

A recently developed velocity map imaging spectrometer has been used to study the photoionization of molecular nitrogen near threshold. The potentialities of the spectrometer have been exploited to measure simultaneously the energy and angular distribution of the photoelectrons corresponding to the residual N2+ X 2Σg v = 0–3 ion states. In a single experiment all the experimental observables, i.e., the total and partial cross sections, their branching ratios and the asymmetry parameter of the angular distributions have been determined.
Custom single-photon avalanche diode with integrated front-end for parallel photon timing applications
Authors: Cammi C. , Panzeri F. , Gulinatti A. , Rech I. , Ghioni M.
Published: March 2012

Emerged as a solid state alternative to photo multiplier tubes (PMTs), single-photon avalanche diodes (SPADs) are nowadays widely used in the field of single-photon timing applications. Custom technology SPADs assure remarkable performance, in particular a 10 counts/s dark count rate (DCR) at low temperature, a high photon detection efficiency (PDE) with a 50% peak at 550 nm and a 30 ps (full width at half maximum, FWHM) temporal resolution, even with large area devices, have been obtained. Over the past few years, the birth of novel techniques of analysis has led to the parallelization of the measurement systems and to a consequent increasing demand for the development of monolithic arrays of detectors. Unfortunately, the implementation of a multidimensional system is a challenging task from the electrical point of view; in particular, the avalanche current pick-up circuit, used to obtain the previously reported performance, has to be modified in order to enable high parallel temporal resolution, while minimizing the electrical crosstalk probability between channels. In the past, the problem has been solved by integrating the front-end electronics next to the photodetector, in order to reduce the parasitic capacitances and consequently the filtering action on the current signal of the SPAD, leading to an improvement of the timing jitter at higher threshold. This solution has been implemented by using standard complementary metal-oxide-semiconductor (CMOS) technologies, which, however, do not allow a complete control on the SPAD structure; for this reason the intrinsic performance of CMOS SPADs, such as DCR, PDE, and afterpulsing probability, are worse than those attainable with custom detectors. In this paper, we propose a pixel architecture, which enables the development of custom SPAD arrays in which every channel maintains the performance of the best single photodetector. The system relies on the integration of the timing signal pick-up circuit next to the photodiode, achieved by modifying the technological process flow used for the fabrication of the custom SPAD. The pixel is completed by an external standard CMOS active quenching circuit, which assures stable timing performance at quite high count rate (>1 MHz).
Design and testing of multi-standard waveguide couplers
Authors: Beeson S. , Neuber A.
Published: March 2012

Most applications that use waveguides are designed for a single frequency or single band of frequency, and thus the waveguide dimensions are chosen for single mode operation. In special cases where multiple frequencies across multiple bands are needed (i.e., probing the temporal response of decaying plasma using a cw source that is generated by a pulsed source), special techniques must be used in order to implement both sources into a single waveguide structure. This paper presents two types of couplers designed to implement x-band frequencies into an s-band system with a large coupling coefficient (< −10 dB) and small reflection coefficient (> −10 dB) at the design frequency of 11 GHz. Along with a discussion on the design procedure, a detailed description on the parameter optimization and initial values estimation is presented. The custom waveguide structures were tested utilizing an Agilent E8364B PNA network analyzer, and showed reasonable agreement with the simulated performance over the frequency range of interest.
Gate effects on DNA translocation through silicon dioxide nanopore
Authors: Yen Pei-chun , Wang Chung-hsuan , Hwang Gwo-Jen , Chou Y. C.
Published: March 2012

The effects of gate voltage on the translocation of DNA molecules through a nanopore are studied. A twenty-fold increase in the translocation time is observed with a positive gate voltage applied, without changing too much of the ionic current. The amplitude of the current blockage by the DNA molecules was reduced by roughly the same factor. At the same time, the number of the blocking events decreases significantly. The applied gate voltage also modulates the scatter plot of the amplitude of the current blockage against the dwell time. The observations are consistent with the recent theoretical results.
Analytical model for reduction of deep levels in SiC by thermal oxidation
Authors: Kawahara Koutarou , Suda Jun , Kimoto Tsunenobu
Published: March 2012

Two trap-reduction processes, thermal oxidation and C+ implantation followed by Ar annealing, have been discovered, being effective ways for reducing the Z1/2 center (EC – 0.67 eV), which is a lifetime killer in n-type 4H-SiC. In this study, it is shown that new deep levels are generated by the trap-reduction processes in parallel with the reduction of the Z1/2 center. A comparison of defect behaviors (reduction, generation, and change of the depth profile) for the two trap-reduction processes shows that the reduction of deep levels by thermal oxidation can be explained by an interstitial diffusion model. Prediction of the defect distributions after oxidation was achieved by a numerical calculation based on a diffusion equation, in which interstitials generated at the SiO2/SiC interface diffuse to the SiC bulk and occupy vacancies related to the origin of the Z1/2 center. The prediction based on the proposed analytical model is mostly valid for SiC after oxidation at any temperature, for any oxidation time, and any initial Z1/2-concentration. Based on the results, the authors experimentally achieved the elimination of the Z1/2 center to a depth of about 90 μm in the sample with a relatively high initial-Z1/2-concentration of 1013 cm−3 by thermal oxidation at 1400 °C for 16.5 h. Furthermore, prediction of carrier lifetimes in SiC from the Z1/2 profiles was realized through calculation based on a diffusion equation, which considers excited-carrier diffusion and recombination in the epilayer, in the substrate, and at the surface.
Nonlinearity and slip behavior of n-hexadecane in large amplitude oscillatory shear flow via nonequilibrium molecular dynamic simulation
Authors: Wang Chen-Chieh , Chang Rong-Yeu
Published: March 2012

Molecular dynamic simulation is used to investigate the viscoelastic properties of n-hexadecane under oscillatory shear flow. Rheometric simulations of an ultra-thin molecular film are studied and compared with the results of a bulk simulation. Strain amplitude sweep tests at a fixed frequency show that strain thinning (the dynamic modulus monotonically decreases with increasing strain amplitude) exists at extreme strain for both bulk and thin film systems. Fourier analysis is performed to characterize the nonlinear behavior of the viscoelasticity. No even harmonic was found in our study even though wall slip occurs. Furthermore, we show that a Fourier series with odd harmonics can be used to perfectly describe the simulation results by plotting Lissajous loops. Shear wave propagation appears when the frequency is larger than a certain value. Moreover, the molecular orientation and molecular potential energies, including those for bonding potential, intra- and intermolecular van der Waals interactions are plotted against the strain amplitude to examine the changes in the microscopic structures with respect to the macroscopic thermodynamic states.
Photoelectron spectroscopy investigations of recombination contacts for tandem organic solar cells
Authors: Olthof Selina , Timmreck Ronny , Riede Moritz , Leo Karl
Published: March 2012

Recombination contacts play an important role in highly efficient organic tandem solar cells. We present a photoelectron spectroscopy study on contact systems that have previously been shown to work efficiently as recombination contacts. Here, the conversion of an electron current into a hole current is realized either by insertion of gold clusters or by a highly doped pn-junction. From the measured energy level alignments, we show that the working principles of these two approaches are significantly different. For gold clusters, the recombination current is promoted by an accumulation of charge carriers, while for doped pn-junctions, it is achieved by tunneling through a depletion layer.
Metal enhanced photoluminescence from Al-capped ZnMgO films: The roles of plasmonic coupling and non-radiative recombination
Authors: Wang Yanjie , He Haiping , Zhang Yalin , Sun Luwei , Hu Liang , Wu Kewei , Huang Jingyun , Ye Zhizhen
Published: March 2012

Aluminium (Al) enhanced emission is investigated by temperature-dependent photoluminescence (PL) from ZnMgO films grown by metal-organic chemical vapor deposition. The PL enhancement is sensitive to both the thickness of Al film and the temperature. The enhancement ratio increases from 3.5 to ∼51 when temperature decreases from room temperature to 20 K. Increased surface plasmon (SP) coupling and decreased non-radiative recombination rate with decreasing temperature are suggested to account for the giant enhancement. The coupling between the ZnMgO excitons and the SP resonance is confirmed by time-resolved PL.
Planar superconducting resonators with internal quality factors above one million
Authors: Megrant A. , Neill C. , Barends R. , Chiaro B. , Chen Yu , Feigl L. , Kelly J. , Lucero Erik , Mariantoni Matteo , O’Malley P. J. J. , Sank D. , Vainsencher A. , Wenner J. , White T. C. , Yin Y. , Zhao J. , Palmstrøm C. J. , Martinis John M. , Cleland A. N.
Published: March 2012

We describe the fabrication and measurement of microwave coplanar waveguide resonators with internal quality factors above 107 at high microwave powers and over 106 at low powers, with the best low power results approaching 2×106, corresponding to ∼1 photon in the resonator. These quality factors are achieved by controllably producing very smooth and clean interfaces between the resonators’ aluminum metallization and the underlying single crystal sapphire substrate. Additionally, we describe a method for analyzing the resonator microwave response, with which we can directly determine the internal quality factor and frequency of a resonator embedded in an imperfect measurement circuit.
Hamiltonian superalgebras of formal vector fields
Authors: Ren Li , Mu Qiang , Zhang Yongzheng
Published: March 2012

The natural filtrations of hamiltonian superalgebras of formal vector fields are proved to be invariant under their automorphism group, by determining the set of ad-quasi-nilpotent elements. Thereby, the automorphism group of these Lie superalgebras are determined.
Application of efficient algorithm for solving six-dimensional molecular Ornstein-Zernike equation
Authors: Ishizuka R. , Yoshida N.
Published: March 2012

In this article, we propose an efficient algorithm for solving six-dimensional molecular Ornstein-Zernike (MOZ) equation. In this algorithm, the modified direct inversion in iterative subspace, which is known as the fast convergent method for solving the integral equation theory of liquids, is adopted. This method is found to be effective for the convergence of the MOZ equation with a simple initial guess. For the accurate averaging of the correlation functions over the molecular orientations, we use the Lebedev-Laikov quadrature. The appropriate number of grid points for the quadrature is decided by the analysis of the dielectric constant. We also analyze the excess chemical potential of aqueous ions and compare the results of the MOZ with those of the reference interaction site model.
Effect of discontinuities in Kohn-Sham-based chemical reactivity theory
Authors: Hellgren Maria , Gross E. K. U.
Published: March 2012

We provide a new derivation of a formula for the Fukui function of density functional chemical reactivity theory which incorporates the discontinuities in the Kohn-Sham reference system. Orbital relaxations are described in terms of the exchange-correlation (XC) kernel, i.e., the derivative of the XC potential with respect to the density and it is shown that in order to correctly measure the reactivity toward a nucleophilic reagent a discontinuity of the XC kernel has to be taken into account. The importance of this finding is illustrated in model molecular systems.
Polarization and interface charge coupling in ferroelectric/AlGaN/GaN heterostructure
Authors: Zhang Min , Kong Yuechan , Zhou Jianjun , Xue Fangshi , Li Liang , Jiang Wenhai , Hao Lanzhong , Luo Wenbo , Zeng Huizhong
Published: March 2012

Asymmetrical shift behaviors of capacitance-voltage (C-V) curve with opposite direction are observed in two AlGaN/GaN metal-ferroelectric-semiconductor (MFS) heterostructures with Pb(Zr,Ti)O3 and LiNbO3 gate dielectrics. By incorporating the switchable polar nature of the ferroelectric into a self-consistent calculation, the coupling effect between the ferroelectric and the interface charges is disclosed. The opposite initial orientation of ferroelectric dipoles determined by the interface charges is essentially responsible for the different C-V characteristics. A critical fixed charge density of −1.27 × 1013 cm−2 is obtained, which plays a key role in the dependence of the C-V characteristic on the ferroelectric polarization. The results pave the way for design of memory devices based on MFS structure with heteropolar interface.
Note: A large aperture four-mirror reflective wave-plate for high-intensity short-pulse laser experiments
Authors: Aurand B. , Rödel C. , Zhao H. , Kuschel S. , Wünsche M. , Jäckel O. , Heyer M. , Wunderlich F. , Kaluza M. C. , Paulus G. G. , Kuehl T.
Published: March 2012

We report on a four-mirror reflective wave-plate system based on a phase-shifting mirror (PSM) for a continuous variation of elliptical polarization without changing the beam position and direction. The system presented and characterized here can replace a conventional retardation plate providing all advantages of a PSM, such as high damage-threshold, large scalability, and low dispersion. This makes reflective wave-plates an ideal tool for ultra-high power laser applications.
Oxygen density dependent band gap of reduced graphene oxide
Authors: Huang Haiming , Li Zhibing , She Juncong , Wang Weiliang
Published: March 2012

We investigated the stability of reduced graphene oxide for oxygen density ranging from 6.25% to 50% with the density functional theory and found the most, the second most, and the third most stable oxygen configurations. The effect of relaxation of lattice on the electronic properties is found to be negligible for low O coverage and crucial for higher O coverage, respectively. The densities of states and the band gaps were calculated. The bandgap is found to be a non-monotonic function of oxygen density, with minima at O/C = 11.1% and 25%.
Simultaneous radiation pressure induced heating and cooling of an opto-mechanical resonator
Authors: Tallur Siddharth , Bhave Sunil A.
Published: March 2012

Cavity opto-mechanics enabled radiation-pressure coupling between optical and mechanical modes of a micro-mechanical resonator gives rise to dynamical backaction, enabling amplification and cooling of mechanical motion. Due to a combination of large mechanical oscillations and necessary saturation of amplification, the noise floor of the opto-mechanical resonator increases, rendering it ineffective at transducing small signals and thereby cooling another mechanical resonance of the system. Here, we show amplification of one mechanical resonance in a micro-mechanical ring resonator while simultaneously cooling another mechanical resonance by exploiting two closely spaced optical whispering gallery mode cavity resonances.