FX-100核磁共振仪频率综合器的检修

该综合器(5610A型)作为多核实验的发射源能输出2～3Vpp,0.1～160MHz不同频率的信号。频率变化由计算机控制。常见故障是无输出,或输出幅度小、使谱仪不能正常工作。上述故障多数与压控振荡器(VCO)控制电压不正常有关(它决定

On the Sources of Private Information in FX Markets

We investigate the source of information advantage in inter-dealer FX trading using data on trades and counterparty identities. In liquid dollar exchange rates, information is concentrated among dealers that trade most frequently and specialize their activity in a particular rate. In cross-rates, traders that engage in triangular arbitrage are best informed. Better-informed traders are also located on larger trading floors. In cross-rates, the ability to forecast flows explains all of the advantage of the triangular arbitrageurs. In liquid dollar rates, specialist traders can forecast both order flow and the component of exchange rate changes that is uncorrelated with flow.

Fx swaps and outright forward validation

UNL - NSBE

Stochastic local volatility model for fx markets

Questa tesi verte sullo studio di un modello a volatilità stocastica e locale, utilizzato per valutare opzioni esotiche nei mercati dei cambio. La difficoltà nell'implementare un modello di tal tipo risiede nella calibrazione della leverage surface e uno degli scopi principali di questo lavoro è quello di mostrarne la procedura.

FX modelling under collateralization

We present the market practice for interest rate yield curves construction and pricing interest rate derivatives. Then we give a brief description of the Vasicek and the Hull-White models, with an example of calibration to market data. We generalize the classical Black-Scholes-Merton pricing formulas, considering more general cases such as perfect or partial collateral, derivatives on a dividend paying asset subject to repo funding, and multiple currencies. Finally we derive generic pricing formulae for different combinations of cash flow and collateral currencies, and we apply the results to the pricing of FX swaps and CCS, and we discuss curve bootstrapping.

Guía didáctica para el uso de la calculadora Casio fx-7400GII en la gráfica de funciones racionales y radicales

El presente trabajo fue realizado con el propósito de relacionar los contenidos de funciones racionales y radicales con los recursos tecnológicos, de manera que éstas se conviertan en formas innovadoras de enseñar y aprender. Para ello se ha propuesto elaborar una guía didáctica sobre el uso de la calculadora Casio fx-7400GII en la gráfica y análisis de funciones racionales y radicales. En ésta propuesta, la calculadora es vista como un recurso didáctico, orientado a promover una metodología constructivista en el proceso de enseñanza-aprendizaje en el mencionado tema. La presente propuesta se debe a que en la educación actual no se están utilizando los recursos tecnológicos como es el caso de la calculadora gráfica en el aula de clase, pues no se disponen de guías didácticassencillas adecuados para una determinada asignatura. Es importante usar la calculadora gráfica en el estudio de las funciones racionales y radicales ya que al momento de realizar su estudio y análisis de forma manual se requiere de mucho tiempo y se convierte en una actividad tediosa, en tanto que se puede ahorrar tiempo y esfuerzo utilizando la calculadora Con la presente propuesta se pretende que los estudiantes alcancen un mejor nivel de conocimiento en el tema, a través del uso de la guía en el aula de clases generando un proceso de enseñanza-aprendizaje más práctico y dinámico

Cyclic mechanical strain guides capillary-like morphology in vitro

Introduction Stretching of tissue stimulates angiogenesis but increased motion at a fracture site hinders revascularisation. In vitro studies have indicated that mechanical stimuli promote angiogenic responses in endothelial cells, but can either inhibit or enhance responses when applied directly to angiogenesis assays. We anticipated that cyclic tension applied during endothelial network assembly would increase vascular structure formation up to a certain threshold. Methods Fibroblast/HUVEC co-cultures were subjected to cyclic equibiaxial strain (1 Hz; 6 h/day; 7 days) using the FlexerCell FX-4000T system and limiting rings for simultaneous application of multiple strain magnitudes (0–13%). Cells were labelled using anti-PECAM-1, and image analysis provided measures of endothelial network length and numbers of junctions. Results Cyclic stretching had no significant effect on the total length of endothelial networks (P > 0.2) but resulted in a strain-dependent decrease in branching and localised alignments of endothelial structures, which were in turn aligned with the supporting fibroblastic construct. Conclusion The organisation of endothelial networks under cyclic strain is dominated by structural adaptation to the supporting construct. It may be that, in fracture healing, the formation and integrity of the granulation tissue and callus is ultimately critical in revascularisation and its failure under severe strain conditions.

A reduction of diffusion in PVA Fricke hydrogels

A modification to the PVA-FX hydrogel whereby the chelating agent, xylenol orange, was partially bonded to the gelling agent, poly-vinyl alcohol, resulted in an 8% reduction in the post irradiation Fe3+ diffusion, adding approximately 1 hour to the useful timespan between irradiation and readout. This xylenol orange functionalised poly-vinyl alcohol hydrogel had an OD dose sensitivity of 0.014 Gy−1 and a diffusion rate of 0.133 mm2 h−1. As this partial bond yields only incremental improvement, it is proposed that more efficient methods of bonding xylenol orange to poly-vinyl alcohol be investigated to further reduce the diffusion in Fricke gels.

Preliminary investigations into the use of a functionalised polymer to reduce diffusion in Fricke gel dosimeters

Purpose A modification of the existing PVA-​FX hydrogel has been made to investigate the use of a functionalised polymer in a Fricke gel dosimetry system to decrease Fe3+ diffusion. Methods The chelating agent, xylenol orange, was chem. bonded to the gelling agent, polyvinyl alc. (PVA) to create xylenol orange functionalised PVA (XO-​PVA)​. A gel was created from the XO-​PVA (20​% w​/v) with ferrous sulfate (0.4 mM) and sulfuric acid (50 mM)​. Results This resulted in an optical d. dose sensitivity of 0.014 Gy-​1, an auto-​oxidn. rate of 0.0005 h-​1, and a diffusion rate of 0.129 mm2 h-​1; an 8​% redn. compared to the original PVA-​FX gel, which in practical terms adds approx. 1 h to the time span between irradn. and accurate read-​out. Conclusions Because this initial method of chem. bonding xylenol orange to polyvinyl alc. has inherently low conversion, the improvement on existing gel systems is minimal when compared to the drawbacks. More efficient methods of functionalising polyvinyl alc. with xylenol orange must be developed for this system to gain clin. relevance.