bluuebunny/crossref_metadata_2025 huggingface dataset:
An apparatus for spatially resolved, temperature dependent reflectance measurements for identifying thermochromism in combinatorial thin film libraries
Authors: Barron S. C. , Patel M. P. , Nguyen Nam , Nguyen N. V. , Green M. L.
Published: November 2015

A metrology and data analysis protocol is described for high throughput determination of thermochromic metal-insulator phase diagrams for lightly substituted VO2 thin films. The technique exploits the abrupt change in near infrared optical properties, measured in reflection, as an indicator of the temperature- or impurity-driven metal-insulator transition. Transition metal impurities were introduced in a complementary combinatorial synthesis process for producing thin film libraries with the general composition space V 1−x−yMxM′yO2, with M and M′ being transition metals and x and y varying continuously across the library. The measurement apparatus acquires reflectance spectra in the visible or near infrared at arbitrarily many library locations, each with a unique film composition, at temperatures of 1 °C–85 °C. Data collection is rapid and automated; the measurement protocol is computer controlled to automate the collection of thousands of reflectance spectra, representing hundreds of film compositions at tens of different temperatures. A straightforward analysis algorithm is implemented to extract key information from the thousands of spectra such as near infrared thermochromic transition temperatures and regions of no thermochromic transition; similarly, reflectance to the visible spectrum generates key information for materials selection of smart window materials. The thermochromic transition for 160 unique compositions on a thin film library with the general formula V 1−x−yMxM′yO2 can be measured and described in a single 20 h experiment. The resulting impurity composition–temperature phase diagrams will contribute to the understanding of metal-insulator transitions in doped VO2 systems and to the development of thermochromic smart windows.
A hybrid continuous-wave terahertz imaging system
Authors: Dolganova Irina N. , Zaytsev Kirill I. , Metelkina Anna A. , Karasik Valeriy E. , Yurchenko Stanislav O.
Published: November 2015

A hybrid (active-passive mode) terahertz (THz) imaging system and an algorithm for imaging synthesis are proposed to enhance the THz image quality. The concept of image contrast is used to compare active and passive THz imaging. Combining the measurement of the self-emitted radiation of the object with the back-scattered source radiation measurement, it becomes possible to use the THz image to retrieve maximum information about the object. The experimental results confirm the advantages of hybrid THz imaging systems, which can be generalized for a wide range of applications in the material sciences, chemical physics, bio-systems, etc.
Status of the RF-driven H− ion source for J-PARC linac
Authors: Oguri H. , Ohkoshi K. , Ikegami K. , Takagi A. , Asano H. , Ueno A. , Shibata T.
Published: November 2015

For the upgrade of the Japan Proton Accelerator Research Complex linac beam current, a cesiated RF-driven negative hydrogen ion source was installed during the 2014 summer shutdown period, with subsequent operations commencing on September 29, 2014. The ion source has been successfully operating with a beam current and duty factor of 33 mA and 1.25% (500 μs and 25 Hz), respectively. The result of recent beam operation has demonstrated that the ion source is capable of continuous operation for approximately 1100 h. The spark rate at the beam extractor was observed to be at a frequency of less than once a day, which is an acceptable level for user operation. Although an antenna failure occurred during operation on October 26, 2014, no subsequent serious issues have occurred since then.
Influence of pH and sequence in peptide aggregation via molecular simulation
Authors: Enciso Marta , Schütte Christof , Delle Site Luigi
Published: November 2015

We employ a recently developed coarse-grained model for peptides and proteins where the effect of pH is automatically included. We explore the effect of pH in the aggregation process of the amyloidogenic peptide KTVIIE and two related sequences, using three different pH environments. Simulations using large systems (24 peptides chains per box) allow us to describe the formation of realistic peptide aggregates. We evaluate the thermodynamic and kinetic implications of changes in sequence and pH upon peptide aggregation, and we discuss how a minimalistic coarse-grained model can account for these details.
Sapphire substrate-induced effects in VO2 thin films grown by oxygen plasma-assisted pulsed laser deposition
Authors: Skuza J. R. , Scott D. W. , Pradhan A. K.
Published: November 2015

We investigate the structural and electronic properties of VO2 thin films on c-plane sapphire substrates with three different surface morphologies to control the strain at the substrate-film interface. Only non-annealed substrates with no discernible surface features (terraces) provided a suitable template for VO2 film growth with a semiconductor-metal transition (SMT), which was much lower than the bulk transition temperature. In addition to strain, oxygen vacancy concentration also affects the properties of VO2, which can be controlled through deposition conditions. Oxygen plasma-assisted pulsed laser deposition allows favorable conditions for VO2 film growth with SMTs that can be easily tailored for device applications.
Reduced dielectric response in spatially varying electric fields
Authors: Hansen J. S.
Published: November 2015

In this paper, the dynamical equation for polarization is derived. From this the dielectric response to a spatially varying electric field is analyzed showing a reduced response due to flux of polarization in the material. This flux is modeled as a diffusive process through linear constitutive relations between the flux and the gradient of the polarization. Comparison between the theory and molecular dynamics simulations confirms this effect. The effect is significant for small length scale electric field variations and the inclusion of the flux is thus important in nanoscale modeling of dielectric response.
Second harmonic generation of q-Gaussian laser beam in preformed collisional plasma channel with nonlinear absorption
Authors: Gupta Naveen , Singh Navpreet , Singh Arvinder
Published: November 2015

This paper presents a scheme for second harmonic generation of an intense q-Gaussian laser beam in a preformed parabolic plasma channel, where collisional nonlinearity is operative with nonlinear absorption. Due to nonuniform irradiance of intensity along the wavefront of the laser beam, nonuniform Ohmic heating of plasma electrons takes place. Due to this nonuniform heating of plasma, the laser beam gets self-focused and produces strong density gradients in the transverse direction. The generated density gradients excite an electron plasma wave at pump frequency that interacts with the pump beam to produce its second harmonics. The formulation is based on a numerical solution of the nonlinear Schrodinger wave equation in WKB approximation followed by moment theory approach. A second order nonlinear differential equation governing the propagation dynamics of the laser beam with distance of propagation has been obtained and is solved numerically by Runge Kutta fourth order technique. The effect of nonlinear absorption on self-focusing of the laser beam and conversion efficiency of its second harmonics has been investigated.
Injection locking of an electronic maser in the hard excitation mode
Authors: Yakunina K. A. , Kuznetsov A. P. , Ryskin N. M.
Published: November 2015

The phenomenon of hard excitation is natural for many electronic oscillators. In particular, in a gyrotron, a maximal efficiency is often attained in the hard excitation regime. In this paper, we study the injection-locking phenomena using two models of an electronic maser in the hard excitation mode. First, bifurcation analysis is performed for the quasilinear model described by ordinary differential equations for the slow amplitude and phase. Two main scenarios of transition to the injection-locked mode are described, which are generalizations of the well-known phase-locking and suppression mechanisms. The results obtained for the quasilinear model are confirmed by numerical simulations of a gyrotron with fixed Gaussian structure of the RF field.
Zero lattice mismatch and twin-free single crystalline ScN buffer layers for GaN growth on silicon
Authors: Lupina L. , Zoellner M. H. , Niermann T. , Dietrich B. , Capellini G. , Thapa S. B. , Haeberlen M. , Lehmann M. , Storck P. , Schroeder T.
Published: November 2015

We report the growth of thin ScN layers deposited by plasma-assisted molecular beam epitaxy on Sc2O3/Y2O3/Si(111) substrates. Using x-ray diffraction, Raman spectroscopy, and transmission electron microscopy, we find that ScN films grown at 600 °C are single crystalline, twin-free with rock-salt crystal structure, and exhibit a direct optical band gap of 2.2 eV. A high degree of crystalline perfection and a very good lattice matching between ScN and GaN (misfit < 0.1%) makes the ScN/Sc2O3/Y2O3 buffer system a very promising template for the growth of high quality GaN layers on silicon.
Particle-in-cell simulations of electron beam control using an inductive current divider
Authors: Swanekamp S. B. , Angus J. R. , Cooperstein G. , Ottinger P. F. , Richardson A. S. , Schumer J. W. , Weber B. V.
Published: November 2015

Kinetic, time-dependent, electromagnetic, particle-in-cell simulations of the inductive current divider are presented. The inductive current divider is a passive method for controlling the trajectory of an intense, hollow electron beam using a vacuum structure that inductively splits the beam's return current. The current divider concept was proposed and studied theoretically in a previous publication [Swanekamp et al., Phys. Plasmas 22, 023107 (2015)]. A central post carries a portion of the return current (I1), while the outer conductor carries the remainder (I2) with the injected beam current given by Ib = I1 + I2. The simulations are in agreement with the theory which predicts that the total force on the beam trajectory is proportional to (I2−I1) and the force on the beam envelope is proportional to Ib. Independent control over both the current density and the beam angle at the target is possible by choosing the appropriate current-divider geometry. The root-mean-square (RMS) beam emittance (εRMS) varies as the beam propagates through the current divider to the target. For applications where control of the beam trajectory is desired and the current density at the target is similar to the current density at the entrance foil, there is a modest 20% increase in εRMS at the target. For other applications where the beam is pinched to a current density ∼5 times larger at the target, εRMS is 2–3 times larger at the target.
Modulation index optimization for optical fringe suppression in wavelength modulation spectroscopy
Authors: Xiong Bo , Du Zhenhui , Li Jinyi
Published: November 2015

Optical fringes constitute one of the major obstacles in the gas detection based on wavelength modulation spectroscopy (WMS). In order to suppress optical fringes, a convenient method of modulation index optimization was presented, using the signal-fringe ratio as a criterion. In addition to suppressing optical fringes, the optimized modulation index enables the detection of gas absorption. This method was demonstrated in a WMS based oxygen sensor. By comparing the sensor performances with and without the use of the optimized modulation index, we showed that the optical fringes are reduced by using the optimized modulation index; furthermore, the system stability and detection limit are improved. More specifically, the long-term fluctuation of the sensor measurement is dramatically reduced by a factor of 8, and a detection limit of as low as 120 ppm (with effective optical path length of 32 cm and integral time of 2.6 s), characterized by the Allan variance, was derived. This method can be applied in other existing WMS systems without the need for additional devices or complex algorithms and has the potential to be used in both laboratory and industrial settings.
Electrically tunable zero dispersion wavelengths in photonic crystal fibers filled with a dual frequency addressable liquid crystal
Authors: Wahle Markus , Kitzerow Heinz-Siegfried
Published: November 2015

We present a liquid crystal (LC) infiltrated photonic crystal fiber, which enables the electrical tuning of the position of zero dispersion wavelengths (ZDWs). A dual frequency addressable liquid crystal is aligned perpendicular on the inclusion walls of a photonic crystal fiber, which results in an escaped radial director field. The orientation of the LC is controlled by applying an external electric field. Due to the high index of the liquid crystal the fiber guides light by the photonic band gap effect. Multiple ZDWs exist in the visible and near infrared. The positions of the ZDWs can be either blue or red shifted depending on the frequency of the applied voltage.
Decoupling electrical and thermal properties in antimony telluride based artificial multilayer for high thermoelectric performance
Authors: Zheng Wenwen , Yang Dongwang , Wei Wei , Liu Fengming , Tang Xinfeng , Shi Jing , Wang Ziyu , Xiong Rui
Published: November 2015

In this work, Sb2Te3/Poly(3,4-ethylenedioxythiophene)/Sb2Te3 sandwich structure was artificially fabricated. This leads to a simultaneous increase of electrical conductivity and decrease of thermal conductivity by tailoring electric flow along the more-electrically conductive parallel path and thermal flow blocked across the less-thermally conductive perpendicular direction. The maximum of thermoelectric figure of merit was increased by 116%, reaching 1.3 at 523 K.
Four-state magnetic configuration in a tri-layer asymmetric ring
Authors: Popescu Horia , Fortuna Franck , Delaunay Renaud , Spezzani Carlo , Lopez-Flores Victor , Jaouen Nicolas , Sacchi Maurizio
Published: November 2015

Ring-shaped multilayered sub-micron dots have the potential for the development of non-volatile multi-bit devices. We show that a Co/Cu/FeNi asymmetric ring can take four distinct remanent magnetic states, each one stabilized by applying a magnetic field pulse along one of four in-plane orthogonal directions. We use element selective x-ray holography for imaging the Co magnetic configuration following a magnetic pulse. Micro-magnetic simulations support our experimental findings; they also provide an estimate of the system magnetization dynamics, setting out the conditions for further time-resolved experiments.
Deep defects and the attempt to escape frequency in organic photovoltaic materials
Authors: Carr John A. , Elshobaki Moneim , Chaudhary Sumit
Published: November 2015

Trap states are well-known to plague organic photovoltaic devices and their characterization is essential for continued progress. This letter reports on both the deep trap profiles and kinetics of trap emission, studied through temperature dependent capacitance measurements. Three polymer based systems relevant to photovoltaics, namely, P3HT:PC60BM, PTB7:PC70BM, and PCDTBT:PC70BM were investigated. Each polymer showed a markedly different deep trap profile, varying in shape from a nearly constant density of states to a sharp Gaussian. In contrast, the frequency of trap emission was similar for each—ca. 108−109 Hz—indicating a universal value and similar trapping mechanisms despite the differences in energetic distribution. The latter result is important in the light of range of conflicting values reported, or higher value (1012 Hz) typically borrowed from crystalline inorganic materials.
Emission switching in carbon dots coated CdTe quantum dots driving by pH dependent hetero-interactions
Authors: Dai Xiao , Wang Hao , Qian Zhicheng , Yi Qinghua , Wang Yun , Cong Shan , Zhao Jie , Sun Yinghui , Huang Jianwen , Xiong Jie , Luo Hongmei , Zou Guifu
Published: November 2015

Due to the different emission mechanism between fluorescent carbon dots and semiconductor quantum dots (QDs), it is of interest to explore the potential emission in hetero-structured carbon dots/semiconducting QDs. Herein, we design carbon dots coated CdTe QDs (CDQDs) and investigate their inherent emission. We demonstrate switchable emission for the hetero-interactions of the CDQDs. Optical analyses indicate electron transfer between the carbon dots and the CdTe QDs. A heterojunction electron process is proposed as the driving mechanism based on N atom protonation of the carbon dots. This work advances our understanding of the interaction mechanism of the heterostructured CDQDs and benefits the future development of optoelectronic nanodevices with new functionalities.
Photoassisted transport in silicon dangling bond wires
Authors: Kleshchonok Andrii , Gutierrez Rafael , Joachim Christian , Cuniberti Gianaurelio
Published: November 2015

We theoretically investigate charge transport through dangling bond (DB) nanostructures built on a passivated silicon (100) surface by selectively removing hydrogen atoms. We focus on dangling bond wires and on T-junctions. In the latter case, destructive quantum interference effects lead to a strong suppression of charge transport mediated by the DB electronic states. We demonstrate, however, that by applying a time periodic voltage, mimicking irradiation with monochromatic light, a dramatic enhancement of the current up to the μA range can be achieved. This result is however limited by the restriction on the AC field strength and frequency that bulk states should minimally contribute to charge transport; otherwise current leakage will set in. Despite this constraint, transconductance values of the order of 10−6 A/V can be achieved, illustrating the potential of the discussed systems to find applications in nanoscale electronics.
Novel MII (M = Mn, Fe, Co, Ni) Coordination Assemblies Based on 2-(((1-(Pyridin-n-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl)thio)pyridine Ligands
Authors: Jiang Lu , Wang Zhe , Bai Shi-Qiang , Loh Xian Jun , Hor T. S. Andy
Published: November 2015

Three novel 1D coordination polymers [M(L1)2(OH2)2(ClO4)2]n (M = Mn (1), Co (2)) and [Ni(L1)2(OH2)2(NO3)2]n (3), and two mononuclear complexes [Fe(L2)2(MeOH)2(ClO4)2] (4) and [Co(L2)2(OH2)2(ClO4)2] (5) were prepared from 2-(((1-(pyridin-n-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl)thio)pyridine ligands (n = 4 (L1), and 2 (L2)). The complexes 1–5 were characterised by single-crystal X-ray diffraction (XRD), powder XRD, thermogravimetric analysis, elemental analysis, infrared, and electrospray ionisation mass spectrometry analyses. The complexes 1–5 showed good purity and thermal stability. The structural outcome of 1–3 is driven by the double and open-bridging coordination mode preference of the spacer L1 which favours the formation of polymeric 18-member metallomacrocycles. Use of an isomeric L2 with different picolyl nitrogen orientation, which favours chelate formation, resulted in mononuclear complexes 4 and 5. This work demonstrates a simple but powerful spacer-directed strategy to define and construct coordination frameworks tuned by different metal characters and hybrid 1,2,3-triazoles.
Fungal cryptochrome with DNA repair activity reveals an early stage in cryptochrome evolution
Authors: Tagua Victor G. , Pausch Marcell , Eckel Maike , Gutiérrez Gabriel , Miralles-Durán Alejandro , Sanz Catalina , Eslava Arturo P. , Pokorny Richard , Corrochano Luis M. , Batschauer Alfred
Published: November 2015

Significance

Photolyases repair UV-B–induced DNA lesions. They form a large protein family together with cryptochrome photoreceptors (cryptochrome/photolyase family, CPF). A more recently discovered CPF subclade consists of DASH (
Drosophila
,
Arabidopsis
,
Synechocystis
, Human)-type cryptochromes (cry-DASH), present in bacteria, plants, animals, and fungi. Cry-DASH are considered as photoreceptors with residual repair activity for DNA lesions in single-stranded DNA. Canonical photolyases repair such lesions in single-stranded and double-stranded DNA. Here, we show that mucoromycotina fungi except
Umbelopsis ramanniana
, which is an early diverging lineage within the mucoralean fungi, encode only cry-DASH. They possess the full spectrum of DNA repair activity as canonical photolyases as exemplified for the
Phycomyces
CryA. This finding is a unique example of CPF evolution where a canonical CPD-photolyase was lost but its function was maintained by cry-DASH.
Glycosylation inhibition reduces cholesterol accumulation in NPC1 protein-deficient cells
Authors: Li Jian , Deffieu Maika S. , Lee Peter L. , Saha Piyali , Pfeffer Suzanne R.
Published: November 2015

Significance

Plasma lipoproteins carrying cholesteryl esters are taken up by low density lipoprotein receptors and delivered to lysosomes, where cholesterol is released and then exported for cellular use. Although cholesterol can partition freely between membranes, it does not freely partition out of lysosomes—Niemann-Pick type C 1 (NPC1) protein is required for cholesterol export. We show here that the requirement for NPC1 is decreased in cells containing lower levels of protein glycosylation. These data support a model in which NPC1 protein helps transfer cholesterol past the glycocalyx barrier that lines the interior of lysosomes.
Genetic polymorphism directs IL-6 expression in fibroblasts but not selected other cell types
Authors: Noss Erika H. , Nguyen Hung N. , Chang Sook Kyung , Watts Gerald F. M. , Brenner Michael B.
Published: November 2015

Significance

IL-6 is an important inflammatory cytokine and treatment target in rheumatoid arthritis. Genetic variation in the IL-6 proximal promoter is well-described, but its contribution to IL-6 regulation is uncertain. Numerous studies have shown contradictory associations between disease states and IL-6 promoter polymorphisms. Synovial fibroblasts are a major IL-6 producer in rheumatoid arthritis. We report a striking association between increased fibroblast IL-6 production and the IL-6 proximal promoter single nucleotide polymorphism rs1800795 minor allele genotype. In stark contrast, no association between human monocyte or HeLa cell IL-6 production and rs1800795 association was observed. These results point to fibroblast-specific pathways in IL-6 regulation and highlight that full understanding of the effects of genetic variation requires examination across cell types.
The particular kindness of friends: ex-Fascists, clientage and the transition to democracy in Italy, 1945–1960
Authors: Evangelista Rhiannon
Published: November 2015

This article examines some of the social implications of Italy's limited purge of the bureaucracy and Fascist political class following the Second World War. Using the postwar personal correspondence of former Fascist government ministers Giuseppe Bottai (1895–1959) and Dino Alfieri (1886–1966), the article analyses the informal networks that promoted the continued influence of these ex-Fascists with high-ranking bureaucrats and other prominent individuals (such as Pope Paul VI and Aldo Moro). Thanks to the long-standing social practice of theraccomandazione, Bottai and Alfieri maintained their Fascist-era connections well into the postwar period, often serving as intermediaries between ‘ordinary Italians' and governmental, political and cultural elites. Although they no longer held political power, these ex-Fascists represented a class of ‘alternative elites' unassociated with the democratic values of the new Republic.
Ferroelectric characterization and growth optimization of thermally evaporated vinylidene fluoride thin films
Authors: Foreman K , Hong N , Labedz C , Shearer M , Ducharme Stephen , Adenwalla S
Published: November 2015

Organic thin films have numerous advantages over inorganics in device processing and price. The large polarization of the organic ferroelectric oligomer vinylidene fluoride (VDF) could prove useful for both device applications and the investigation of fundamental physical phenomena. A VDF oligomer thin film vacuum deposition process, such as thermal evaporation, preserves film and interface cleanliness, but is challenging, with successful deposition occurring only within a narrow parameter space. We report on the optimal deposition parameters for VDF oligomer thin films, refining the parameter space for successful deposition, resulting in a high yield of robust ferroelectric films. In particular, we investigate the influence of deposition parameters on surface roughness, and the role that roughness plays in sample yield. The reliable production of ferroelectric films allowed us to perform detailed measurements of previously unreported properties, including the Curie temperature, the temperature and thickness dependence of the coercive field, the melting temperature, and the index of refraction. The ability to successfully grow robust, switchable, well-characterized films makes VDF oligomer a viable candidate in the field of organic ferroelectrics.
The Grip of the Given
Authors: Hanna Robert
Published: November 2015

The thesis of Non-Conceptualism about mental content says that not all mental contents in the intentional or representational acts or states of minded animals are necessarily or constitutively determined by their conceptual capacities, and that at least some mental contents are necessarily or constitutively determined by their non-conceptual capacities. Non-Conceptualism is sometimes, but not always, combined with the further thesis that non-conceptual capacities and contents can be shared by rational human animals, non-rational human minded animals, and non-human minded animals alike. Chapter 2 analyzes the general theory of non-conceptual content and conceptual content. Highlights of the account include, first, a defense of Non-Conceptualism by means of an extended, step-by-step argument for the existence, concept-autonomy, and concept-independence of essentially non-conceptual content; second, a corresponding refutation of Conceptualism; and third, an application of the doctrine that necessarily whatever is mental is conscious—The Deep Consciousness Thesis—to essentially non-conceptual content.
Radically Naïve Realism
Authors: Hanna Robert
Published: November 2015

What is rational human sense perception? Can we correctly sense-perceive our world, and thereby know it? And if the answer to both of those questions is “yes,” then how is this possible? Chapter 3 provides an analysis of these questions, with the lofty goal of changing the way we normally think about our perceptual engagement with the world. In addition, the chapter uses the theory of non-conceptual content developed in chapter 2 as the basis of a new theory of direct or naïve realism about sense perception, including a new solution to Molyneux’s problem, and a theory of perceptual self-knowledge. A central feature of the account is its radical version of metaphysical disjunctivism, the doctrine that all sense perception is veridical and categorically different from hallucination and illusion.
Truth in Virtue of Intentionality,Or, The Return of the Analytic-Synthetic Distinction
Authors: Hanna Robert
Published: November 2015

What is the analytic-synthetic distinction? According to the contemporary Kantian conception offered in this book, it is the categorically sharp contrast between two fundamentally different kinds of truth, distinguished in terms of what each kind is “true-in-virtue-of.” Chapter 4 tells the thrilling three-part story of how the analytic-synthetic distinction departed from mainstream Analytic philosophy, not with a bang but a whimper, why the analytic-synthetic distinction must now return with a bang, and what that bang must sound like. In so doing, the chapter deploys the earlier accounts of conceptual content and non-conceptual content in order to provide a full explanation and vindication of the analytic-synthetic distinction, including a theory of synthetic a priori truth. This vindication includes an extended critique of Quine’s critique of the analytic-synthetic distinction, and also an explicit argument against the Kripke-Putnam conceptions of the necessary a posteriori and the contingent a priori.
The Morality of Logic
Authors: Hanna Robert
Published: November 2015

What is the nature of logic? According to one very plausible and widely accepted definition, logic is the science of the necessary relation of consequence between the premises and the conclusion of a valid argument. In keeping with this characterization, chapter 5 works out an argument for the categorical normativity of logic and its intrinsic role in rational mental representation or intentionality per se, including all modes of rational human cognition and intentional action. A central pay-off of this argument is that it can be used to solve the problems of the explanatory and justificatory status of logic (the logocentric predicament), the epistemic status of logic, and, finally, Quine’s Predicament (that every truth is fallible, but “sheer logic” is infallible).
Rationalism Regained 2
Authors: Hanna Robert
Published: November 2015

Chapter 7 presents an account of the nature of a priori knowledge specifically, in three steps: a discussion of the nature of apriority; a consideration of the a priori–a posteriori distinction and its eleven major varieties; and an examination of the nature of transcendental idealism as the metaphysical foundation of an adequate theory of a priori knowledge. The majority of the chapter is devoted to critically clearing a place in logical space for a contemporary Kantian theory of rational intuitions, Kantian Intuitionism, as the core of the book’s account of a priori knowledge. Furthermore, in the context of working out solutions to the three versions of The Benacerraf Dilemma, this chapter discusses the nature and epistemic status of intuitions, with special reference to rational intuitions, and offers a corresponding critique of the contemporary critique of intuitions by Experimental Philosophy.
Rationalism Regained 3
Authors: Hanna Robert
Published: November 2015

Chapter 8 presents solutions to all three versions of The Benacerraf Dilemma—namely, The Original Benacerraf Dilemma, The Extended Benacerraf Dilemma, and The Generalized Benacerraf Dilemma—and develops a new structuralist account of the nature of mathematics and logic (Kantian Structuralism) alongside a new rational-intuition-based account of the nature of mathematical and logical a priori knowledge (Kantian Intuitionism), comparing and contrasting the two differing accounts with Charles Parsons’s theory. The chapter then moves on to work out a positive or anti-skeptical, innatist, rational-intuition-based solution to The Extended Benacerraf Dilemma. Following this, it then goes on to generalize that solution to The Generalized Benacerraf Dilemma. These solutions and accounts, in turn, presuppose and indirectly vindicate a Kant-inspired rational-intuition-based approach to meta-philosophy.
Investor–State Arbitration and the Argentine Cases
Authors: Bücheler Gebhard
Published: November 2015

This chapter first discusses the most important characteristics of the current system of investor–State arbitrations and the developments that led up to it. It then presents a series of cases that have fuelled the debate on the legitimacy of investor–State arbitration: the arbitral jurisprudence arising from the 2001–3 Argentine financial crisis. This jurisprudence demonstrates how tribunals handle conflicts between investor rights and the public interest in the context of certain treaty provisions and other concepts that frequently lie at the core of investor–State arbitrations.
Real Exchange Rate Undervaluation and Poverty
Authors: Elbadawi Ibrahim A.
Published: November 2015

The recent growth literature suggests that countries that have managed to engineer real exchange rate (RER) undervaluation episodes have been able to achieve stable growth transitions. This chapter provides evidence on the direct poverty-reducing impact of such a strategy, beyond its indirect effect through the growth channel. Controlling for household consumption growth and initial inequality, RER undervaluation was found to be negatively but non-monotonically associated with poverty. Specifically, an RER undervaluation below 50 per cent will likely have a direct poverty-reducing effect. This is not a binding constraint for most countries, since the median country in the sample of the poverty spells was undervalued at only 12 per cent. In view of this finding and the evidence from the macroeconomic literature on the relative exogeneity of the real exchange rate, it is argued that real currency undervaluation might be a viable public policy instrument for poverty reduction for most developing countries.
Introduction
Authors: Samek-Lodovici Vieri
Published: November 2015

This chapter introduces the analysis of Italian contrastive focus developed in the rest of the book. Besides functioning as a shortened summary of the main arguments in the book, briefly describing the focus evacuation analysis and the role of prosody, it explains why a new analysis of Italian focalization is necessary and theoretically relevant beyond the specific language at hand. It does so by briefly introducing the current mainstream view based on the presence of a unique left-peripheral focus projection and providing a first set of arguments from Italian showing why such an analysis is untenable. This chapter also characterizes the type of focalization under scrutiny in the rest of the book and briefly describes the possible analyses available for right dislocation and why one was favoured over the other.
Contrastive focus and right dislocation
Authors: Samek-Lodovici Vieri
Published: November 2015

This chapter examines the interaction of focalization and right dislocation. It first shows that right dislocation can displace higher constituents to the right of lower foci, giving the false impression that these foci have moved upwards. It then examines cases where right dislocation targets constituents containing a focus, showing how such focus is obligatorily evacuated from these phrases. As a result, evacuated foci—including Rizzi’s left-peripheral foci—are preceded by hanging and CLLD topics located at the left-periphery of the clause and only followed by right-dislocated phrases. Furthermore, and in sharp contrast with Rizzi’s analysis, evacuated foci do not c-command the constituents following them, as expected if these are right-dislocated phrases moved to a TP-external position as claimed here. Finally, the chapter also examines the co‑occurrence of wh-phrases and left-peripheral foci, showing how the right-dislocated nature of the constituents following left-peripheral foci correctly predicts when co-occurrence is grammatical or ungrammatical.
The role of prosody
Authors: Samek-Lodovici Vieri
Published: November 2015

This chapter examines how the syntax–prosody interface, and specifically how prosodic constraints governing the position of Italian stress determine the in-situ location of Italian contrastive focalization as well as the optional raising of lower unfocused constituents immediately before a higher focused phrase. Both phenomena are shown to maximize the alignment of main stress with the right edge of the clause, as required by the prosodic constraints. Focus occurs in situ because any movement upwards would move the focused constituent and the associated stress further away from the clause right edge. Similarly, lower unfocused phrases moving before focus enhance the right alignment of the associated main stress. The same constraints and constraint conflicts are shown to account for how the internal structure of post-focal constituents determines which of its parts may move above a preceding focus and which cannot.
Focus structure
Authors: Cruschina Silvio
Published: November 2015

This chapter presents an analysis of the focus structure of four types of Italo-Romance there sentence: existentials, inverse locatives, deictic locatives, and presentationals. In contrast with traditional approaches which have focused on the pragmatic and discourse status of the existential pivot, the chapter takes an approach that considers both the construction as a whole and its individual components, thus shedding light on a number of subtle differences between the four types of there sentence, which would otherwise have gone unnoticed. At the same time, it is suggested that the shared morphosyntactic properties of there sentences are motivated by their not being predicate focus structures. In particular, it is claimed that existential sentences typically occur in sentence focus, while inverse and deictic locatives are most typically associated with argument focus. Lastly, presentational there sentences share the sentence focus character of existentials, but have distinct semantic and syntactic properties, and occur in different discourse contexts.
Predication and argument realization
Authors: Bentley Delia
Published: November 2015

This chapter analyses predication and argument realization in existentials and other there sentences. After testing against the dialect findings the hypothesis that existentials are locatives and the alternative view that the existential pivot is the predicate of existential constructions, the former analysis is ruled out and the latter adopted. The chapter draws a distinction between existential constructions with referential and non-referential pivots, and advances a proposal on predication and argument realization in each of these existential types. While the pivot is the predicate in both cases, it is proposed here that referential pivots take an argument position in the semantics of the construction, which explains why they exhibit patterns of argument behaviour. The chapter then revisits the key insight of the locative hypothesis, making an alternative proposal, which captures the relatedness of existentials and locatives. A detailed analysis of argument structure and predication in locative and presentational there sentences follows.
The beginning
Authors: Blood Peter
Published: November 2015

This short chapter traces the historical development of the laser diode from the original concept of stimulated emission by Einstein, realised by Maiman in the ruby laser via the maser of Charles Townes, through the first homojunction semiconductor laser diodes to the heterostructure laser diode proposed by Kroemer and Alferov. This led to the double-heterostructure laser diode, which is the basis of modern diode lasers, providing both the optical waveguide and confinement in quantum wells and quantum dots.
The planar waveguide
Authors: Blood Peter
Published: November 2015

The planar waveguide controls the overlap of the laser mode with the gain material, which drives the stimulated emission process and determines the divergence of the beam on leaving the laser, important for coupling into external elements such as fibres. Through the optical confinement factor and the optical mode width, the waveguide provides the connection between the gain generated by the gain medium (the material gain) and the amplification experienced by the laser mode (the modal gain). Starting with Maxwell’s equations, this chapter provides an introduction to optical modes of transverse electric and transverse magnetic polarisation in a passive, planar waveguide in the weak guiding approximation. The chapter ends with a short introduction to the internal mode loss in a waveguide.
Quantum confinement
Authors: Blood Peter
Published: November 2015

The properties of the states produced by quantum confinement in double heterostructures are obtained by solving the spatial part of Schrödinger’s equation for a one-dimensional potential well with barriers of finite height. The apparently formidable task of dealing with the very large number of atoms in a solid is greatly simplified by exploiting the periodic nature of crystals through Bloch’s theorem and the envelope functions. Schrödinger’s equation gives, first, the wavefunctions that are used to calculate transition rates via the matrix element and, second, the energies of the confined states and hence the photon energies at which light interactions occur. This is used to develop simple models for the energy states in quantum dots with rectangular and parabolic potential profiles. Quantum wells provide confinement in only one dimension. Freedom in the other two dimensions produces a continuum of states characterised by a density-of-states function.
Gain and emission in quantum dots
Authors: Blood Peter
Published: November 2015

The absorption, gain, and spontaneous emission spectra due to optical transitions in a layer of quantum dots in the slab waveguide of a laser are derived in terms of the dipole matrix element and optical cross section of the dots. This leads to the relation between peak modal gain and intrinsic spontaneous recombination current that is at the heart of device design. Injection lasers use self-assembled dots and so an inhomogeneous distribution of dot sizes, and therefore confined state energies, is a fact of life: this inhomogeneous broadening influences the shape of the spectra. The electron occupation of the states in each dot is determined by capture and emission of carriers injected into the wetting layer. The use of thermal distributions specified by Fermi functions and random population of dots are considered.
Rate equations for dot state occupation
Authors: Blood Peter
Published: November 2015

Rate equations for electrons in dot states can be used to avoid the assumption that electrons are distributed thermally according to Fermi functions. The equations treat the processes of capture and emission of electrons from and to the wetting layer, and of recombination between conduction and valence dot states. Electron capture and emission are controlled by generation and absorption of phonons, and the rate equations are solved in the steady states for a dot system in equilibrium with a Bose–Einstein phonon energy distribution. At high temperature, when the emission rate to the wetting layer exceeds the recombination rate, a thermal, Fermi electron distribution is established, whereas at low temperature, where the emission rate is very slow compared with the recombination rate, the occupation probability of dot states is independent of their energy. This is the random population regime.
Optical transitions in quantum wells
Authors: Blood Peter
Published: November 2015

Optical transitions in quantum wells occur between closely spaced states associated with unconfined motion in the plane of the well within sub-bands formed by confinement across the well. The energy spacing of the unconfined states is much less than the homogeneous linewidth, so the transition rate is given by Fermi’s Golden Rule. Initial and final states must have the same in-plane k-vector (k-selection) and this leads to definition of the transition density. The transition probability is also determined by the overlap integral between initial and final confined state envelope functions, which limits transitions in rectangular wells to sub-bands of the same index. Confinement also produces polarisation dependence of the momentum matrix element, which depends upon whether the valence band is light or heavy hole in character. Expressions are derived for modal gain and spontaneous emission together with the spectrally integrated emission rate at low carrier density using the Boltzmann approximation.
Gain and recombination current in quantum wells
Authors: Blood Peter
Published: November 2015

Examples of typical quantum well gain and spontaneous emission spectra are used to obtain the gain–current relation between peak gain and radiative recombination current, and its temperature dependence, which provide the basis for laser design. The influence of elastic strain and its benefits for laser operation are considered, as are the effects of non-parabolic bands. The effects of band gap narrowing, Coulomb enhancement of gain, and wavefunction dephasing are described, all due to interactions between the large number of carriers present in a working laser device.
Rate equations for laser operation
Authors: Blood Peter
Published: November 2015

Rate equations for the electron and photon populations provide insight into the variation of light output with current and the high-frequency modulation response of the laser. Above threshold the average photon lifetime exceeds the cavity round-trip time. The steady-state solution of these equations shows that the gain never becomes exactly equal to the optical loss, as assumed in the traditional description of threshold, the small difference being made up by the spontaneous emission coupled into the lasing mode given by the spontaneous emission factor. Steady-state solutions are also obtained for quantum dot lasers in the random population regime, where quasi-equilibrium is not established, by solving electron, photon, and phonon coupled rate equations. Rate equations also give the small signal modulation response of the laser and the resonance frequency, including the influence of carrier transport in quantum well devices. The chapter ends with remarks on what constitutes evidence for laser action.
Device structures
Authors: Blood Peter
Published: November 2015

The operation of a laser is influenced by its structure as well as the characteristics of the gain region. The simplest structure is a Fabry–Perot laser that embodies a slab waveguide and feedback by reflection at the end facets. Some lasers use optical feedback from Bragg gratings to improve control of the wavelength. General properties of gratings and specification of the Bragg wavelength are described. Devices with the axis of the cavity in the plane of the epitaxial layers are termed ‘in-plane lasers’ wherein the light propagates along the gain layer and is emitted from the edge of the chip; examples include ridge waveguide lasers, distributed feedback lasers and distributed Bragg reflector lasers. By contrast, in vertical-cavity surface-emitting lasers (VCSELs) the light propagates perpendicular to the plane of the gain layer between two closely spaced multilayer Bragg reflectors. The threshold condition for each of these structures is considered.
Threshold and the light–current characteristic
Authors: Blood Peter
Published: November 2015

The light–current characteristic is the most basic measurement that can be made of the performance of a laser diode, giving its threshold current and external efficiency. For conventional laser diodes a threshold in this characteristic is usually adequate evidence that laser action has been achieved. The contributions to the threshold current of real devices by current spreading, non-radiative recombination by Shockley–Read–Hall (SRH) and Auger processes, and carrier leakage over heterobarriers are described. These are not usually included in theoretical calculations of gain–current characteristics. The information that can be extracted from the threshold current density alone is limited; however, systematic measurements as a function of cavity length can give greater insight into operation of the device, for example in certain circumstances analysis of the differential quantum efficiency provides a value for the optical mode loss. Analysis of the characteristics of quantum dot and well devices is described.