Dissertations / Theses on the topic 'Double charge exchange reaction'

This thesis discusses the pion double charge exchange (DCX) reaction ¹⁸0(π⁺,π⁻)¹⁸Ne at 50 MeV. Transitions to the ground state of ¹⁸Ne, which is the double-isobaric-analogue state (DIAS) of ¹⁸0, have been isolated. The differential cross sections for DIAS transitions have been measured at 6 scattering angles from 18.2° to 122.6°. The experiment was performed at TRIUMF in December 1984 using the QQD low energy pion spectrometer [26]. The differential cross section angular distribution is forward peaked, falling from 4.7±0.5 μb/sr at 0° (by extrapolation) to 0.61±0.11 μb/sr at 122.6°. The total (angle-integrated) cross section is 16.2±1.2 μb. DCX measurements are expected to give information on nuclear structure that is hard to obtain by other reactions. This information includes short range correlations and neutron-proton density differences. However, before such information can be extracted the mechanism for DCX must be understood. The aim of this experiment was to provide more data to test the various theories of the DCX mechanisms. The implications of the results for several theories of DCX are discussed. The forward peaking of DCX angular distributions at 50 MeV was unexpected. 50 MeV single charge exchange (SCX) angular distributions are forward dipped e.g. [14], a result of the cancellation of the 0° s and p wave scattering amplitudes for the reaction p(π⁺,π⁰)n. Early DCX calculations were based on the simple sequential mechanism. This assumes DCX proceeds via 2 successive SCX reactions, with the isobaric analogue as the intermediate state. These calculations predicted forward dipping and small cross sections for DCX [13,15]. The data shows this mechanism is an over-simplification. The standard model for π-nucleus scattering is the optical potential. Johnson and Siciliano are developimg a potential with which to calculate elastic, SCX and DCX cross sections [48,38,22]. They include second, order terms, important in DCX because the reaction must involve scattering by at least two nucleons. By using a general form for the optical potential they include contributions from excited intermediate states. Miller has suggested the forward peaking is due to the presence of six-quark clusters in the nucleus [16]. His model reproduces the data for 50 MeV DCX on ¹⁸0 and ¹⁴C at forward angles. Karapiperis and Kobayashi have used the Δ-hole model to calculate elastic, SCX and DCX cross sections [19]. They obtain fair agreement with data for a range of nuclei and energies. Jennings et al. [22] are developing a model in which short range correlations produce the forward peaking. This work is at an early stage. More DCX measurements are needed to choose between the various models. Measurements at 50 MeV are particularly valuable because the simple sequential mechanism is small, allowing other mechanisms to be observed. Further data such as excitation functions below 80 MeV and angular distributions for other nuclei are needed.
Science, Faculty of
Physics and Astronomy, Department of
Graduate

This study is inserted in a research line that aims to access the Nuclear Matrix Element (NME) involved in the half-life of the 0 bb decay, by measuring the cross sections of heavy-ion induced Double Charge Exchange (DCE) reactions with high accuracy. The basic point is that the initial and nal state of both 0 bb decay and DCE processes are the same. In addition, both processes pass through the same intermediate state and the transition operators have a similar mathematical structure. This work shows for the rst time experimental data on heavy-ion DCE reaction in a wide range of transferred momenta, with an acceptable statistical signi cance and good angular and energy resolution. In particular (18O,18Ne) reaction at 270 MeV incident energy on 40Ca target was investigated. In order to estimate the contribution of the concurrent channels the 40Ca(18O,18F)40K single charge exchange intermediate channel and the competing processes 40Ca(18O,20Ne)38Ar two-proton transfer and 40Ca(18O,16O)42Ca two-neutron transfer were also studied. The experiment was performed at Laboratori Nazionali del Sud (LNSINFN) in Catania using a 270 MeV energy 18O Cyclotron beam impinging on a 279 g/cm2 thick 40Ca target. The ejectiles were momentum analysed by the MAGNEX large acceptance magnetic spectrometer and detected by its focal plane detector. The energy spectra and angular distributions have been extracted. The data analysis of experimental results have established that the transition to 40Args: is dominated by the direct processes. Finally, an innovative technique to infer on the nuclear matrix elements by measuring the cross section of a double charge exchange nuclear reaction was proposed. The main assumption are that the DCE reaction is a twostep charge exchange and a surface localized process. The model adopted to describe the cross section of the DCE reaction consists in a generalization of the well-established factorization of the single charge-exchange cross section, valid under certain hypothesis, discussed in the thesis. Therefore, the cross section could be factorized in a nuclear structure term, containing the matrix elements, and a nuclear reaction one (unit cross section). Despite the used approximations, the extracted strength and nuclear matrix elements are reasonable within +-50%, signalling that the main physics content has been kept.

We performed theoretical studies on Heavy ion charge exchange reactions, at low energies, focusing on the interplay between nuclear structure and reaction dynamics. Such studies allow also to enlight the existence of a relation between Heavy ion double charge exchange (HIDCE) cross section at forward scattering angles and double beta ($\beta\beta$) decay nuclear matrix element (NME) of the target or projectile nucleus considered. HIDCE reactions can be described as a sequence of two single charge changing processes, which can be correlated or not, thus mimicking $0\nu\beta\beta$ and $2\nu\beta\beta$ decays, respectively. The dominance of the former mechanism would allow to gain information on $0\nu\beta\beta$ NME, thus in turn allowing to determine neutrino Majorana mass with a significant accuracy, if such weak decay were observed.

Bibliography: p. 67-69.
Using the Time-of-Flight facility at the National Accelerator Centre at Faure, the (p, n) charge-exchange reaction has been studied at intermediate energies of 120, 160 and 200 MeV, and at angles of 0°, 2° and 4°. In this work the data collected for the ⁹⁰Zr target will be presented. The influence on the data from slow neutrons due to previous pulses is discussed and the best manner of removing them from the spectra is recommended. It is shown how the background cosmic rays can be utilised to measure the intrinsic resolution of the detectors and to obtain an estimate of the neutron energy threshold. The differential cross-sections for the states corresponding to Fermi and Gamow-Teller transitions were extracted from the time spectra. The sum of the strength of all the discrete Gamow-Teller states was determined and compared to the Ikeda Sum Rule. It was found that only 50% of the sum could be accounted for in the discrete states. An overview of the theory that has been developed to extract Gamow-Teller strengths from the (p, n) cross-sections is given. Some of the theoretical models that have been used to describe the ⁹⁰Zr(p, n)⁹⁰ Nb reaction and account for the missing Gamow-Teller strength are briefly discussed.

Le but principal de la collaboration GBAR est de mesurer le comportement d'atomes d'antihydrogène sous l'effet de la gravité terrestre. Ceci est fait en mesurant la chute libre classique d'atomes d'antihydrogène, qui est un test direct du principe d'équivalence faible pour l'antimatière. La première étape de l'expérience est de produire des ions d'antihydrogène et de les amener dans un piège de Paul, où ils peuvent être refroidis à une température de l'ordre du μK en utilisant la technique du refroidissement sympathique avec des ions Be⁺ eux-mêmes mis dans leur état fondamental par la technique Raman à bande latérale. Une température de l'ordre du μK correspond à une vitesse de la particule de l'ordre de 1 m/s. Une fois cette vitesse atteinte, l'ion antihydrogène peut être neutralisé et commence sa chute. Ceci permet une précision de 1 % sur la mesure de l’accélération gravitationnelle g pour l’antimatière avec environ 1500 événements. Cependant, pour mesurer la chute libre, il faut d'abord produire l'ion antihydrogène. Celui-ci est formé dans les réactions d'échange de charge entre des antiprotons et des antihydrogènes avec du positronium. Positronium et atomes d'antihydrogène peut se trouver soit à l’état fondamental, soit dans un état excité. Une étude expérimentale de la mesure de la section efficace de ces deux réactions est décrite dans cette thèse. La production de l'atome d'antihydrogène ainsi que de l'ion se passe à l’intérieur d'une cavité. La formation d'un antihydrogène ion lors d'une interaction entre faisceaux requiert environ 5x10⁶ antiprotons/paquet et quelques 10¹¹ Ps/cm⁻³ de densité de positronium à l’intérieur d'une cavité. Celle-ci est produite par un faisceau contenant 5x10¹⁰ positrons par paquet. La production de faisceaux aussi intenses avec les propriétés requises est en soi un challenge. Le développement de la source de positrons de GBAR est décrite. Celle-ci est basée sur un accélérateur linéaire à électrons de 9 MeV. Le faisceau d’électrons est incident sur une cible de tungstène où les positrons sont créés par rayonnement de freinage (gammas) et création de paires. Une partie des positrons ainsi créés diffusent à nouveau dans un modérateur de tungstène en réduisant leur énergie à environ 3 eV. Ces particules sont re-accélérées à une énergie d'environ 53 eV. Aujourd'hui, le flux mesuré de positrons est au niveau de 6x10⁷ e⁺/s, soit quelques fois. Puis la thèse comporte une courte description des préparatifs pour les faisceaux d'antiprotons ou de protons, terminée par un chapitre sur le taux de production attendu d'atomes et d'ions d'antihydrogène. En aval de la réaction, les faisceaux d'antiprotons, d'atomes et d'ions d'antihydrogène sont guidés vers leur système de détection. Ceux-ci ont été conçus de façon à permettre la détection d'un à plusieurs milliers d'atomes d'antihydrogène, un seul ion antihydrogène et tous les 5x10⁶ antiprotons. Ceci est particulièrement difficile parce que l'annihilation des antiprotons crée beaucoup de particules secondaires qui peuvent perturber la mesure d'un atome ou ion. La majeure partie de la thèse consiste en la description des bruits de fond attendus pour la détection des atomes et ions d'antihydrogène. De plus, le système de détection permet de mesurer les sections efficaces pour les réactions symétriques de production d'atomes et d'ions hydrogèene par échange de charge entre protons et positronium. La partie production d’antihydrogène ions de l’expérience a été complètement installée au CERN en 2018. Les premiers tests avec des antiprotons provenant du décélérateur ELENA ont été effectués. Actuellement, l’expérience est testée avec des positrons et des protons, de façon à former des atomes et ions hydrogène. Une optimisation de la production de ces ions de matière aidera à se préparer pour la prochaine période de faisceau d'antiprotons en 2021
The main goal of the GBAR collaboration is to measure the Gravitational Behaviour of Antihydrogen at Rest. It is done by measuring the classical free fall of neutral antihydrogen, which is a direct test of the weak equivalence principle for antimatter. The first step of the experiment is to produce the antihydrogen ion and catch it in a Paul trap, where it can be cooled to μK temperature using ground state Raman sideband sympathetic cooling. The μK temperature corresponds to particle velocity in the order of 1 m/s. Once such velocity is reached, the antihydrogen ion can be neutralised and starts to fall. This allows reaching 1 % precision on the measurement of the gravitational acceleration g for antimatter with about 1500 events. Later, it would be possible to reach 10⁻⁵ - 10⁻⁶ precision by measuring the gravitational quantum states of cold antihydrogen. However, in order to measure the free fall, firstly the antihydrogen ion has to be produced. It is formed in the charge exchange reactions between antiproton/antihydrogen and positronium. Positronium and antihydrogen atoms can be either in a ground state or in an excited state. An experimental study of the cross section measurement for these two reactions is described in the presented thesis. The antihydrogen atom and ion production takes place in a cavity. The formation of one antihydrogen ion in one beam crossing requires about 5x10⁶ antiprotons/bunch and a few 10¹¹ Ps/cm⁻³ positronium density inside the cavity, which is produced with a beam containing 5x10¹⁰ positrons per bunch. The production of such intense beams with required properties is a challenging task. First, the development of the positron source is described. The GBAR positron source is based on a 9 MeV linear electron accelerator. The relatively low energy was chosen to avoid activation of the environment. The electron beam is incident on a tungsten target where positrons are created from Bremsstrahlung radiation (gammas) through the pair creation process. Some of the created positrons undergo a further diffusion in the tungsten moderator reducing their energy to about 3 eV. The particles are re-accelerated to about 53 eV energy and are adiabatically transported to the next stage of the experiment. Presently, the measured positron flux is at the level of 6x10⁷ e⁺/s, which is a few times higher than intensities reached with radioactive sources. Then, the thesis features a short description of the antiproton/proton beam preparations, finalised with a chapter about the expected antihydrogen atom and ion production yield. After the reaction, antiproton, antihydrogen atom, and ion beams are guided to the detection system. It is made to allow for detection from 1 to a few thousand antihydrogen atoms, a single antihydrogen ion and all 5x10⁶ antiprotons. It is especially challenging because antiproton annihilation creates a lot of secondary particles which may disturb measurements of single antihydrogen atoms and ions. The main part of the Thesis is the description of the expected background for the antihydrogen atom and ion detection. Additionally, the detection system allows measuring the cross sections for the symmetric reactions of a hydrogen atom and ion production through charge exchange between protons and positronium. The antihydrogen ion production part of the experiment was fully installed at CERN in 2018. The first tests with antiprotons from the ELENA decelerator were done. Currently, the experiment is being commissioned with positrons and protons, in order to perform the hydrogen atom and ion formation. The optimisation of the ion production with matter will help to be fully prepared for the next antiproton beam time in 2021

Thesis (Ph.D.)--Baylor University, 2007.
In the abstract "CF3COCo(CO)3PPh3, CF3, Bu3SnH, CF3H, [Co(CO)4]-, [Co(CO)3(PPh3)]-, C2F4, C6F5Co(CO)3PPh3, C6F5, C6F5H, C6F5D, CF3COCo(CO)3PPh3, and Co-C(acyl)" are subscript. Includes bibliographical references (p. 205-213).

Multi-step photoinduced electron transfer takes place over a large distance in the photosynthetic reaction centres (PRCs). Electron donor in this life-spending event is the photo-excited 'special pair', a unit of two electronically coupled porphyrinoid chromophores. Bacteriopheophytin and two quinone molecules function as electron acceptors and contribute to the charge separation with almost unit quantum efficiency. The natural photosynthetic reaction centre is the most sophisticated molecular electronic device to date and interest is high in increasing our understanding of the basic quantum mechanical principles behind efficient electron transfer and ultimately copying Nature and construct similar efficient devices. Two main approaches towards a better understanding of the mechanisms involved have been taken. The more biological disciplines isolate, cultivate and alternate reaction centres whereas synthetic chemists prefer to construct well-defined models that mimic certain aspects of the reaction centres. Such a synthetic approach is described in the 'Synthesis of Advanced 'Special Pair' Models for the Photosynthetic Reaction Centre'. The aspect to be mimicked is the 'special pair'. One or two porphyrins in a well-defined spatial disposition (kinked or non-kinked in respect to each other) were to act as electron donor in rigid bichromophoric and trichromophoric systems. A tetracyanonaphthoquinodimethane (TCNQ) unit was employed as the electron acceptor in the series of dyads synthesised. The TCNQ acceptor was replaced by a naphthoquinone (NQ) primary acceptor covalently linked to a TCNQ secondary electron acceptor in the series of triads. Rigid norbornylogous bridges held the chromophores in place and Diels-Alder methodology as well as condensation reactions were applied to link donor, bridge and acceptor components. Despite larger interchromophoric separation than in the natural 'special pair', the two porphyrin chromophores of the series of 'special pair' dyads show some interaction and thereby prove the success of our approach towards 'special pair' mimics. Strong fluorescence quenching in the porphyrin-TCNQ dyads indicates the sought after electron transfer process. A number of synthetic problems experienced and overcome in the synthesis of the series of triads led to discovery of a one-step 'bis-ketonisation' from an olefin under Sharpless bis-hydroxylation conditions with N-methylmorpholine-N-oxide. High pressure was applied to circumvent a lack of reactivity in the condensation reaction used to attach the porphyrin moieties (one or two) to the donor backbone. For the linkage of donor, bridge and acceptor component, a procedure was developed and successfully applied to give the giant mono-porphyrin-NQ-TCNQ trichromophore. In a similar manner 'special pair' trichromophoric systems should be available as part of future work.

Porphyrins derivatized with electron donating and electron withdrawing groups can be used for artificial photosynthesis. Four new compounds, two electron donors and two electron acceptors, have been synthesized for prospective porphyrin linkages.

Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2009.
Committee Chair: Bridgette Barry; Committee Member: El-Sayed, Mostafa; Committee Member: Fahrni, Christoph; Committee Member: Kröger, Nils; Committee Member: McCarty, Nael. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph. D.)--University of Akron, Dept. of Chemistry, 2005.
"August, 2005." Title from electronic dissertation title page (viewed 09/24/2005). Advisor, David A. Modarelli; Committee members, Matthew Espe, Michael Taschner, Chrys Wesdemiotis, Stephanie Lopina; Department Chair, David Perry; Dean of the College, Charles B. Monroe; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Ce travail de thèse s'intéresse à la relation entre la composition des phases Hydroxydes Doubles Lamellaires (HDL) et leurs propriétés structurales. La première partie de ce manuscrit est consacrée à la formation et aux propriétés structurales de ces matériaux. L'effet de la nature des cations (MgII, NiII, CoII ; AlIII, FeIII) et de leur stoechiométrie dans le feuillet (MII/MIII E [2 ; 10]) constitue les axes principaux de ces travaux. L'étude du comportement hydrolytique d'un mélange de cations divalents et trivalents en fonction de leurs proportions en solution a permis de proposer un mécanisme topotactique de formation de ces phases HDL. Il a aussi été montré que la variabilité stoechiométrique du feuillet ne dépend que de la nature des cations. Ainsi, des modèles électrostatiques ont été proposés afin de rationaliser et prédire la gamme de composition de ces phases HDL en fonction de la nature des cations. La seconde partie est dédiée aux propriétés du milieu interfoliaire. Une étude couplant des analyses par spectroscopies vibrationnelles infrarouge et Raman et par diffraction des Rayons X a permis d'apporter une description précise de l'influence de la nature des cations, et de leurs stoechiométries sur l'organisation des anions dans le milieu interfoliaire (Cl-, CO32-, NO3-, ClO4-, acides aminés). Le rôle de l'eau dans ces phases a également été étudié. Dans le cas des hybrides organo-minéraux, il a été montré que la charge dicte l'orientation des acides aminés intercalées et par conséquent, leur réactivité envers la formation de la liaison peptidique. Également, les propriétés énantioselectives du domaine interfeuillet sont mises en avant pour la formation de peptides
This manuscript is devoted to the comprehension of the relationship between the composition of Layered Double Hydroxides (LDH) and their structural properties. The first part of this manuscript is focalized on the formation and the structural properties of these materials. The influence of the cationic nature (MgII, NiII, CoII ; AlIII, FeIII) and their stoichiometries within the layer (MII/MIII E [2 ; 10]) constitutes the main axis of these investigations. The study of the hydrolytic behavior of a solution containing a mixture of divalent and trivalent cations as a function of their relative proportion allowed to propose a topotactic mechanism of formation of LDH phases. Moreover, it has been showed that the composition range is solely dependent on the nature of the cations. Thus, electrostatic models were designed to rationalize and predict the composition range as a function of the cationic nature. The second part is concerned with the properties of the interlayer domain. A joint study, coupling vibrational spectroscopies (Infrared and Raman) and X-ray diffraction allowed a detailed description of the influence of the cations and their stoichiometries on the organization of the interlayer anions (Cl-, CO32-, NO3-, ClO4-, aminoacids). The role of the interlayer water has also been investigated. Concerning hybrid organo-minerals, it has been showed that the layer charge dictates the orientation of the interlayered aminoacids, and consequently, their reactivity toward the formation of the peptide bonds. The enantioselective properties of the interlayer domain are highlighted toward the formation of peptides

I. Etude des mécanismes de relaxation mis en jeu dans Cl2, Br2, I2 isolés en matrice, après excitation en UV proche ou lointain : émission structurée (transitions vibroniques) pour Cl2en UV proche et transitions électroniques avec interaction Rydberg-Valence en UV lointain; émission dans le visible pour Br2 et I2 quelle que soit l'énergie d'excitation; étude théorique des processus de relaxation. II. Observation d'ions moléculaires simplement ou doublement chargés, formés par échange de charge simple ou double étudié par spectrométrie de translation; analyse des règles de sélection : conservation du spin et observation des seuls états singlets pour Cl2, influence croissante du couplage spin-orbite lorsqu'on passe de Cl2, à Br2 puis I2.

Extracellular neuroelectronic interfacing has important applications in the fields of neural prosthetics, biological computation and whole-cell biosensing for drug screening and toxin detection. While the field of neuroelectronic interfacing holds great promise, the recording of high-fidelity signals from extracellular devices has long suffered from the problem of low signal-to-noise ratios and changes in signal shapes due to the presence of highly dispersive dielectric medium in the neuron-microelectrode cleft. This has made it difficult to correlate the extracellularly recorded signals with the intracellular signals recorded using conventional patch-clamp electrophysiology. For bringing about an improvement in the signal-to-noise ratio of the signals recorded on the extracellular microelectrodes and to explore strategies for engineering the neuron-electrode interface there exists a need to model, simulate and characterize the cell-sensor interface to better understand the mechanism of signal transduction across the interface. Efforts to date for modeling the neuron-electrode interface have primarily focused on the use of point or area contact linear equivalent circuit models for a description of the interface with an assumption of passive linearity for the dynamics of the interfacial medium in the cell-electrode cleft. In this dissertation, results are presented from a nonlinear dynamic characterization of the neuroelectronic junction based on Volterra-Wiener modeling which showed that the process of signal transduction at the interface may have nonlinear contributions from the interfacial medium. An optimization based study of linear equivalent circuit models for representing signals recorded at the neuron-electrode interface subsequently proved conclusively that the process of signal transduction across the interface is indeed nonlinear. Following this a theoretical framework for the extraction of the complex nonlinear material parameters of the interfacial medium like the dielectric permittivity, conductivity and diffusivity tensors based on dynamic nonlinear Volterra-Wiener modeling was developed. Within this framework, the use of Gaussian bandlimited white noise for nonlinear impedance spectroscopy was shown to offer considerable advantages over the use of sinusoidal inputs for nonlinear harmonic analysis currently employed in impedance characterization of nonlinear electrochemical systems. Signal transduction at the neuron-microelectrode interface is mediated by the interfacial medium confined to a thin cleft with thickness on the scale of 20-110 nm giving rise to Knudsen numbers (ratio of mean free path to characteristic system length) in the range of 0.015 and 0.003 for ionic electrodiffusion. At these Knudsen numbers, the continuum assumptions made in the use of Poisson-Nernst-Planck system of equations for modeling ionic electrodiffusion are not valid. Therefore, a lattice Boltzmann method (LBM) based multiphysics solver suitable for modeling ionic electrodiffusion at the mesoscale neuron-microelectrode interface was developed. Additionally, a molecular speed dependent relaxation time was proposed for use in the lattice Boltzmann equation. Such a relaxation time holds promise for enhancing the numerical stability of lattice Boltzmann algorithms as it helped recover a physically correct description of microscopic phenomena related to particle collisions governed by their local density on the lattice. Next, using this multiphysics solver simulations were carried out for the charge relaxation dynamics of an electrolytic nanocapacitor with the intention of ultimately employing it for a simulation of the capacitive coupling between the neuron and the planar microelectrode on a microelectrode array (MEA). Simulations of the charge relaxation dynamics for a step potential applied at t = 0 to the capacitor electrodes were carried out for varying conditions of electric double layer (EDL) overlap, solvent viscosity, electrode spacing and ratio of cation to anion diffusivity. For a large EDL overlap, an anomalous plasma-like collective behavior of oscillating ions at a frequency much lower than the plasma frequency of the electrolyte was observed and as such it appears to be purely an effect of nanoscale confinement. Results from these simulations are then discussed in the context of the dynamics of the interfacial medium in the neuron-microelectrode cleft. In conclusion, a synergistic approach to engineering the neuron-microelectrode interface is outlined through a use of the nonlinear dynamic modeling, simulation and characterization tools developed as part of this dissertation research.
Ph.D.
Doctorate
Physics
Sciences
Physics

碩士
逢甲大學
財務金融學所
92
The existence of international financial market linkage is a very important issue to the modern asset pricing theory. Numerous studies have been documented the return and volatility series of several international equity markets are asymmetrical functions of past information from U.S. equity market. Recently, the double-threshold model has been evolved as a preferred approach to examine that effect. However, none of previous work has been investigated asymmetric reaction of national stock return and foreign exchange market return to the U.S. news simultaneously. By utilizing a multivariate double-threshold GARCH model, this study examines whether the co-movements of return and volatility series among national stock market and foreign exchange market in each underlying sample countries including Taiwan, Japan, Canada, U.K., Germany and Australia react asymmetrically to the U.S. stock-return news. Consistence with the finding of the market integration literature, the empirical result of this study further suggests the transmission of bad news from U.S. stock-return news indeed cause a large magnitude of fluctuation in return and volatility series of sample national stock and foreign exchange markets than which of good news.