118 research outputs found
An account by Johannes Funck from the synod of Kozminek in 1555 (the contribution to the contacts of Protestants from the Duchy of Prussia, Poland and Bohemia)
No full textThe article consists of three parts. The first part addresses the condition of research on the synod of Kozminek of 1555, during which the religious union between Polish protestants and the Bohemian Brethren was concluded. In the second part of the article the author presents the reasons for Johannes Funck (a preacher of Albrecht of Prussia) being sent to the synod. Prince Albrecht wanted to become familiar with the religious situation in Poland in connection with the stance of the Polish noblemen at the seym in Piotrków in May 1555 insisting on the approval of the Augsburg Confession of 1530 and the convening of the national synod. He was also interested in the attitude of the Bohemian Brethren towards the theological disagreement in his duchy connected with the preachings of Andreas Osiander, which he supported. The third part of the article constitutes an account of the talks of Johannes Funck with the leader of the Bohemian Brethren – Jan Černy and the Polish protestants. The beliefs of Jan Černy dispelled the fears of J. Funck that the opponent of A. Osiandra’s preachings – Antoni Bodestein – a pastor from Ostróda was a member of the Church of the Bohemian Brethren. It is interesting that the Protestant noblemen gathered at the synod declared that they were prepared to offer military support to the prince if need be
Theoretical and experimental investigation of electronic transport phenomena in oxide based resistive switches
No full textIn this work the conduction mechanism of resistive switching devices is investigated, which could be used as novel data storage memory or for the realization of neuromorphic computing architectures. Those memory cells consist of an insulating oxide between two metal contact electrodes. Under an externally applied electric field the migration of oxygen vacancies is initiated. This reconfiguration induces a non-volatile change in the electrical resistance, which is the central state variable. For a better physical understanding, the investigation of the internal conduction mechanism is of fundamental meaning. In several studies, the conduction mechanism is not the main focus. As a result, several conduction mechanism are suggested for comparable current-voltage (I-V) characteristics.A privilege of this work is the opportunity to investigate the current transport experimentally and also apply different simulation methods. Two representative resistive switching cells based on SrTiO3 and HfO2 are considered, which significantly distinguish in their I-V curve. Measurements and simulations of the SrTiO3 based cell show a transport over the conduction band. The simulation in the case of HfO2 show a transport over the defect states. Independent of this difference, the resistive switching mechanism in both cases could be unified to a huge extend. Additionally, a volatile threshold switching based on a pure electronic nature is explored.At the beginning of this work, electrical measurements on the SrTiO3 based cell are applied at different temperatures. A typical method to find the conduction mechanism is the fitting of analytical equations to the I-V curve. Even though the fitting of the Schottky emission equation leads to positive impressions, a detailed review reveal physical contradictions. The same contradictions generally occur for thermal activated current transport equations. For this reason an atomic quantum mechanical approach is used by means of density functional theory combined with the non-equilibrium Greens function formalism (DFT + NEGF). These ab initio simulations reveal a band transport, which is limited by a tunnelling process through the Schottky barrier at the metal electrode. This simulation method reproduce parts of the measurements. In an additional investigation the simulations are applied, to analyse the Schottky barrier lowering effect. The problem of this method is the huge requirement of computational resources, which limits the flexibility. Consequently, not all measurements could be reproduced with DFT + NEGF. Therefore, a continuum single band transport model is developed on the basis of the DFT + NEGF results. This model could predict correctly all trends of the temperature dependent I-V curves. Based on this, a compact model compatible simplification is developed for the detected current transport. This allows a generalized description of the current in the compact model and replaces the previous preselected conduction mechanism. The descriptions so far reference to the SrTiO3 based resistive cell with a strong exponential I-V dependence. Other resistive switching systems distinguishes because of a less strong I-V dependence. For such an example a HfO2 based resistive switching cell is investigated using DFT + NEGF. Here, the current transport is mainly transmitted over defect states and limited by the defect to electrode tunnelling. In both cases, the tunnelling connection to the electrode is the limiting mechanism. This observation allows to generalize the resistive switching mechanism in HfO2 and SrTiO3. In both cases the resistance change is induced by an increasing and decreasing tunnelling distance to the electrode. Besides the ionic non-volatile resistive switching a further effect of volatile resistive switching is investigated. This effect is purely electronic and based on a thermal instability, which leads to a high number of thermal activated charge carriers. This thermal instability occurs at a certain threshold voltage, which can be predicted in continuum model. Out of it, empirical equation are derived for the dependence on material constants and cell geometry. The same thermal instability could be found in the compact model at comparable voltages. Hence, this volatile switching could have a high relevance for the dynamic of the resistive switching
Tax systems in transition
Get PDFHow have tax systems, whose primary role is to raise resources to finance public expenditures, evolved in the transition countries of Eastern Europe and the former Soviet Union? The authors find that: (1) the ratio of tax revenue-to-GDP decreased largely due to a fall in revenue from corporate income tax; (2) the fall in revenue from the corporate income tax led to a decline in the importance of income taxes, notwithstanding a rise in the share of individual income tax; (3) social security contributions together with payroll taxes became less important in the Commonwealth of Independent States; and (4) domestic indirect taxes gained in importancein overall tax revenues. Apart from the increased role of personal income taxation, these developments go in a direction opposite to those observed in poor countries as they get richer. They show a key aspect of transition, namely a movement from a system where the government exercised a preeminent claim on output and income before citizens had access to the remainder, to one with a greatly diminished role for the public sector, as reflected in a lower ratio of public expenditure to GDP, where the government needs to collect revenue in order to spend. Can expected levels of public expenditure be financed by the basic instruments of a modern tax system without creating significant distortions in the private sector? The authors suggest that transition countries, depending on their stage of development, should aim for a tax revenue-to-GDP ratio in the range of 22 to 31 percent, comprising value-added tax (6 to 7 percent), excises (2 to 3 percent), income tax (6 to 9 percent), social security contribution together with payroll tax (6 to 10 percent), and other taxes such as on trade and on property (2 percent). The authors'analysis also sheds light on the links between tax policy, tax administration, and the investment climate in transition countries.Municipal Financial Management,Environmental Economics&Policies,Banks&Banking Reform,Public Sector Economics&Finance,Economic Theory&Research,Environmental Economics&Policies,Public Sector Economics&Finance,Economic Theory&Research,Banks&Banking Reform,Municipal Financial Management
Comprehensive Model of Electron Conduction in Oxide-Based Memristive Devices
No full textMemristive devices are two-terminal devices that can change their resistance state upon application of appropriate voltage stimuli. The resistance can be tuned over a wide resistance range enabling applications such as multibit data storage or analog computing-in-memory concepts. One of the most promising classes of memristive devices is based on the valence change mechanism in oxide-based devices. In these devices, a configurational change of oxygen defects, i.e. oxygen vacancies, leads to the change of the device resistance. A microscopic understanding of the conduction is necessary in order to design memristive devices with specific resistance properties. In this paper, we discuss the conduction mechanism proposed in the literature and propose a comprehensive, microscopic model of the conduction mechanism in this class of devices. To develop this microscopic picture of the conduction, ab initio simulation models are developed. These simulations suggest two different types of conduction, which are both limited by a tunneling through the Schottky barrier at the metal electrode contact. The difference between the two conduction mechanisms is the following: for the first type, the electrons tunnel into the conduction band and, in the second type, into the vacancy defect states. These two types of conduction differ in their current voltage relation, which has been detected experimentally. The origin of the resistive switching is identical for the two types of conduction and is based on a modification of the tunneling distance due to the oxygen vacancy induced screening of the Schottky barrier. This understanding may help to design optimized devices in terms of the dynamic resistance range for specific applications
Does strict employment protection discourage job creation? Evidence from Croatia
Get PDFEmployment protection legislation in Croatia is among the most strict in Europe. Firing is difficult and costly, and flexible forms of employment are limited. Is this apparent rigidity reflected-as one would expect based on standard economic theory-in low labor market dynamics? Is job creation low and hiring limited? Is the job security of insiders achieved at the cost of outsiders not being able to enter thelabor market? The author attempts to answer these questions by examining job flows. If the employment protection legislation is binding, then job and worker turnover should be low. He shows that this is indeed the case. Hiring is limited and the average job tenure is very long in Croatia. Job destruction is low, however job creation is still lower. The result is accumulation of unemployment, in large part due to new labor market entrants not being able to find a job. The high degree of job protection also seems to strengthen the bargaining position of insiders and results in relatively high wages. So, wages in Croatia are higher than among its competitors, even after adjusting for productivity. These high labor costs are likely to contribute to limited job creation in existing firms, but also are likely to discourage the entry of-and thus job creation in-new firms. The author presents evidence that firm growth has been indeed limited in Croatia, contributing to the low employment level. The author examines other potential causes of high unemployment in Croatia (the unemployment benefit system, labor taxation, the wage structure, and skill and spatial mismatches). He argues that they do not play a substantial part in accounting for poor labor market outcomes in Croatia. The author concludes that the stringent employment protection legislation is the key labor market institution behind low job creation and high unemployment. Based on this he recommends specific measures aimed at liberalizing the labor market to foster job creation and employment.Labor Management and Relations,Labor Policies,Labor Markets,Environmental Economics&Policies,Trade Finance and Investment,Labor Markets,Labor Management and Relations,Labor Standards,Banks&Banking Reform,Environmental Economics&Policies
An atomistic view on the Schottky barrier lowering applied to SrTiO3/Pt contacts
No full textThe interface between a metal and a semiconductor is known as Schottky contact and a key factor in semiconductor technologies. Those interfaces normally build an energetic barrier, which is responsible for the exponential current voltage dependence. Analytical models often describe the right trend for the description of the Schottky barrier height, but fail to predict the barrier properties quantitatively correct. To overcome this problem atomistic and quantum mechanical approaches are required such as the here applied density functional theory combined with the non-equilibrium Greens function method. So far, these methods have rarely been applied to wide band gap metal oxides, which leads to a lack in the understanding of oxide electronics. The presented study deals with the image force induced Schottky barrier lowering of a SrTiO3/Pt interface as a model system for wide band gap metal-oxide Schottky contacts. The Schottky barrier lowering is investigated for the case of different doping concentrations/positions and for different voltages. From a defect chemical point of view, oxygen vacancies act as donors in many metal oxides and dominate the electronic conduction in oxide electronics. Consequently, we investigated the Schottky barrier lowering induced by oxygen vacancies. The second doping mechanism is achieved in the sense of classical doping using Nb impurities, which form a conventional n-type donor. The atomistic simulation reveals the Schottky barrier lowering effect for both type of dopants. The results are compared to a standard analytical model regarding the Schottky barrier lowering
The III-Nitride Double Heterostructure Revisited: Benefits for Threshold Voltage Engineering of MIS Devices
No full textFalling for lions: transformations of the vampire character in literature
Get PDFDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Letras/Inglês e Literatura Correspondente, Florianópolis, 2013A Literatura Gótica é responsável por dar vida à criaturas que têm assombrado o sonho das pessoas e alimentado a imaginação de muitos por mais de um século. Entretanto, nenhuma dessas criaturas tivera a chance de estar no centro das atenções como o vampiro contemporâneo. Na primeira década do século XXI, Edward Cullen, o vampiro adolescente criado pela americana Stephenie Meyer em Crepúsculo (2005), capturou o coração de uma legião de jovens leitores ao redor do planeta. O personagem de Crepúsculo é responsável por fazer com que vampiros e, consequentemente a ficção gótica, receber atenção renovada por parte do público leitor, permitindo a proliferação de livros com temáticas vampirescas, especialmente aqueles que são direcionados aos jovens adultos. Edward também exemplifica uma nova personificação de vampiro que guarda pouca semelhança com Drácula, do romance homônimo de Bram Stoker, publicado em 1897. A análise das mudanças físicas e de personalidade que colocam Drácula e Edward em lados opostos da mesma moeda constitui o foco principal da presente investigação, que também se compromete a explorar as mudanças já sinalizadas em Louis e Lestat, do best-seller Entrevista com o Vampiro, de Anne Rice, em 1976. Além disso, esta pesquisa defende que Edward é um herói apesar de sua natureza vil. Nesta mudança de paradigma está, possivelmente, a explicação para a popularidade de Edward Cullen e o personagem vampiresco contemporâneo. Parece que os vampiros vieram para ficar. E não apenas sob a luz do luarAbstract : Gothic Literature is responsible for producing creatures that have haunted people's dreams and have fostered the imagination of many for more than a century. However, none of such creatures have ever been in the spotlight as the contemporary vampire. In the first decade of the twenty-first century, Edward Cullen, the teenager vampire from American author Stephenie Meyer's literary phenomenon Twilight (2005), has captured the hearts of a generation of young readers from all over the planet. The Twilight character is responsible for making vampires, and therefore Gothic fiction receive renewed attention from the readership, allowing a proliferation of vampire-related novels, especially those that are aimed at young adults. Edward also epitomizes a new depiction of the vampire character that bears little resemblance to Dracula, from Bram Stoker's eponymous novel, published in 1897. The analysis of the physical aspects and personality traits that place Dracula and Edward on different sides of the same coin are the core of the present investigation, which is also committed to explore the changes already signalized in the Ricean vampires Louis and Lestat, from the 1976 best-seller Interview with the Vampire. In addition, this research claims that Edward is a hero despite his villainous nature. In such change of paradigm lies, arguably, the explanation for the popularity of Edward Cullen and the contemporary vampire character, signalizing that the bloodsuckers are here to stay. And not just under moonligh
Resistive Switching Behavior in ReRAM Cells of Oxide Bilayers grown by Atomic Layer Deposition
No full textDesign rules for threshold switches based on a field triggered thermal runaway mechanism
No full textWe investigate a new type of threshold switching devices, which is based on a purely electronic phenomena. These threshold switches are polarity independent and switch abruptly from a high resistive state to a low resistive state at a threshold voltage. The device stays in this low resistive state as long as a high voltage drops over the device. When the voltage is reduced, the low resistive state is lost and the device switches back to the initial high resistive state. This makes these threshold switches highly interesting as selector elements for resistive switching memory concepts, based on device arrays, which are the prerequisite for new applications like logic-in-memory concepts. The threshold switching considered here is based on a combination of a Poole–Frenkel conduction mechanism and Joule heating. Hence, it is not strongly restricted to specific materials rather it is connected to the physical quantities of the Poole–Frenkel conduction mechanism and the thermal conductance. This enables to design the threshold switch to its application requirements by adjusting the relevant physical material properties or designing the device geometry. Here we present a theoretical study, which tackles the influence of several material properties and the device design. From this simulation model the impact on technical important figures of merits is determined, such as the threshold switching voltage and the selectivity
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