Relevant bibliographies by topics / Modulation solaire

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Modulation solaire'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Modulation solaire"

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Gololobov, Peter, Prokopy Krivoshapkin, Germogen Krymsky, and Sardaana Gerasimova. "INVESTIGATING THE INFLUENCE OF GEOMETRY OF THE HELIOSPHERIC NEUTRAL CURRENT SHEET AND SOLAR ACTIVITY ON MODULATION OF GALACTIC COSMIC RAYS WITH A METHOD OF MAIN COMPONENTS." Solar-Terrestrial Physics 6, no. 1 (April 1, 2020): 24–28. http://dx.doi.org/10.12737/stp-61202002.

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The work studies the cumulative modulating effect of the geometry of the interplanetary magnetic field's neutral current sheet and solar activity on propagation of galactic cosmic rays in the heliosphere. The role of each factor on the modulation of cosmic rays is estimated using a method of main components. The application of the method to experimental data on solar activity, to the tilt angle of the neutral sheet, and cosmic ray intensity for a long period from 1980 to 2018 allows us to reveal the temporal dynamics of roles of these factors in the modulation. The modulation character is shown to strongly depend on the polarity of the Sun’s general magnetic field. Results of the study confirm the existing theoretical concepts of the heliospheric modulation of cosmic rays and reflect its peculiarities for almost four full cycles of solar activity.
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Mishra, R. K., and R. A. Mishra. "Modulation of Cosmic Rays Along with Solar and Heliospheric Anomalies." Kosmìčna nauka ì tehnologìâ 13, no. 6 (November 30, 2007): 99–108. http://dx.doi.org/10.15407/knit2007.06.099.

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Довбня, Борис, Boris Dovbnya, Борис Клайн, Boris Klain, Анатолий Гульельми, Anatol Guglielmi, Александр Потапов, and Alexander Potapov. "Spectrum of frequency modulation of serpentine emission as a reflection of the solar fluctuation spectrum." Solar-Terrestrial Physics 3, no. 1 (May 5, 2017): 73–77. http://dx.doi.org/10.12737/article_58fd6dfaa04833.19557687.

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We study frequency modulation of serpentine emission (SE), using data from the Vostok Antarctic station. It is shown that the previously observed 5-minute modulation of the SE carrier frequency is the most prominent and stable in the emission spectrum. Frequency fluctuations of this period are present in about 70 % of the total SE observation time under moderately quiet geomagnetic conditions (Kp=0–2). We performed a per-pixel processing of SE dynamic spectra and found that the power spectrum of the signal frequency modulation contains a clearly visi-ble peak at periods close to 5 minutes. A detailed study shows the emission spectrum matching the frequency range of the solar photospheric oscilla-tions. The results of the analysis allow us to conclude that the 5-minute modulation of the SE carrier fre-quency can be viewed as a reflection of photospheric fluctuations with the same period that is typical for the solar eigenoscillations.
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El-Daly, Sherien M., Shaimaa A. Gouhar, Amira M. Gamal-Eldeen, Fatma F. Abdel Hamid, Magdi N. Ashour, and Nahla S. Hassan. "Synergistic Effect of α-Solanine and Cisplatin Induces Apoptosis and Enhances Cell Cycle Arrest in Human Hepatocellular Carcinoma Cells." Anti-Cancer Agents in Medicinal Chemistry 19, no. 18 (February 7, 2020): 2197–210. http://dx.doi.org/10.2174/1871520619666190930123520.

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Aim: The clinical application of cisplatin is limited by severe side effects associated with high applied doses. The synergistic effect of a combination treatment of a low dose of cisplatin with the natural alkaloid α-solanine on human hepatocellular carcinoma cells was evaluated. Methods: HepG2 cells were exposed to low doses of α-solanine and cisplatin, either independently or in combination. The efficiency of this treatment modality was evaluated by investigating cell growth inhibition, cell cycle arrest, and apoptosis enhancement. Results: α-solanine synergistically potentiated the effect of cisplatin on cell growth inhibition and significantly induced apoptosis. This synergistic effect was mediated by inducing cell cycle arrest at the G2/M phase, enhancing DNA fragmentation and increasing apoptosis through the activation of caspase 3/7 and/or elevating the expression of the death receptors DR4 and DR5. The induced apoptosis from this combination treatment was also mediated by reducing the expression of the anti-apoptotic mediators Bcl-2 and survivin, as well as by modulating the miR-21 expression. Conclusion: Our study provides strong evidence that a combination treatment of low doses of α-solanine and cisplatin exerts a synergistic anticancer effect and provides an effective treatment strategy against hepatocellular carcinoma.
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Paudel, Jamuna Risal, Charlotte Davidson, Jun Song, Itkin Maxim, Asaph Aharoni, and Helen H. Tai. "Pathogen and Pest Responses Are Altered Due to RNAi-Mediated Knockdown of GLYCOALKALOID METABOLISM 4 in Solanum tuberosum." Molecular Plant-Microbe Interactions® 30, no. 11 (November 2017): 876–85. http://dx.doi.org/10.1094/mpmi-02-17-0033-r.

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Steroidal glycoalkaloids (SGAs) are major secondary metabolites constitutively produced in cultivated potato Solanum tuberosum, and α-solanine and α-chaconine are the most abundant SGAs. SGAs are toxic to humans at high levels but their role in plant protection against pests and pathogens is yet to be established. In this study, levels of SGAs in potato were reduced by RNA interference (RNAi)-mediated silencing of GLYCOALKALOID METABOLISM 4 (GAME4)—a gene encoding cytochrome P450, involved in an oxidation step in the conversion of cholesterol to SGA aglycones. Two GAME4 RNAi lines, T8 and T9, were used to investigate the effects of manipulation of the SGA biosynthetic pathway in potato. Growth and development of an insect pest, Colorado potato beetle (CPB), were affected in these lines. While no effect on CPB leaf consumption or weight gain was observed, early instar larval death and accelerated development of the insect was found while feeding on leaves of GAME4 RNAi lines. Modulation of SGA biosynthetic pathway in GAME4 RNAi plants was associated with a larger alteration to the metabolite profile, including increased levels of one or both the steroidal saponins or phytoecdysteroids, which could affect insect mortality as well as development time. Colonization by Verticillium dahliae on GAME4 RNAi plants was also tested. There were increased pathogen levels in the T8 GAME4 RNAi line but not in the T9. Metabolite differences between T8 and T9 were found and may have contributed to differences in V. dahliae infection. Drought responses created by osmotic stress were not affected by modulation of SGA biosynthetic pathway in potato.
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Yanchukovsky, Valery. "Solar activity and Earth seismicity." Solar-Terrestrial Physics 7, no. 1 (March 29, 2021): 67–77. http://dx.doi.org/10.12737/stp-71202109.

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Using the results of continuous long-term observations over 50 years (including solar cycles 20–24), we study the relationship between Earth’s seismicity and solar activity. An increase in the number of strong earthquakes on the planet occurs during the decline phase of solar activity when charged particle fluxes from high-latitude coronal holes increase, as well as during solar minimum when the intensity of galactic cosmic rays reaches a maximum. The change in the number of strong earthquakes (with magnitude 6) is considered in terms of variations in the intensity of galactic cosmic rays, Forbush decreases, and ground level enhancements in solar cosmic rays (GLE events). The number of strong earthquakes is shown to increase after Forbush decreases with a time lag from ~1 to ~6 days depending on the amplitude of Forbush decrease and after GLE events the number of strong earthquakes increases by ~8 day. In the number of strong earthquakes, a six-month variation is observed, which seems to follow the six-month variation in cosmic rays with a delay of ~1–2 months. It is surmised that the relationship between solar activity and Earth’s seismicity seems to be mediated through the modulation of galactic cosmic rays and atmospheric processes that provoke the occurrence of earthquakes in regions where the situation has already been prepared by tectonic activity.
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Kupriyanova, Elena, Dmitrii Kolotkov, Valery Nakariakov, and Anastasiia Kaufman. "QUASI-PERIODIC PULSATIONS IN SOLAR AND STELLAR FLARES. REVIEW." Solar-Terrestrial Physics 6, no. 1 (April 1, 2020): 3–23. http://dx.doi.org/10.12737/stp-61202001.

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This paper provides an overview of the state-of-the-art studies of oscillatory processes in solar and stellar flares, based on modern observational data from ground-based and space-borne instruments with high temporal, spatial, and spectral resolution in different bands of the electromagnetic spectrum. We examine the mecha-nisms that generate flare emission and its quasi-periodic modulation. We discuss similarities and differences be-tween solar and stellar flares, and address associated problems of superflares on the Sun and space weather. Quasi-periodic pulsations (QPPs) of flare emission are shown to be an effective tool for diagnosing both the flare processes themselves and the parameters of flaring plasmas and accelerated particles. We consider types of QPPs, their statistical properties, and methods of analysis, taking into account the non-stationarity of the QPPs’ parameters. We review the proposed mechanisms of QPPs and summarize open questions.
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Krainev, Mikhail. "MANIFESTATIONS OF TWO BRANCHES OF SOLAR ACTIVITY IN THE HELIOSPHERE AND GCR INTENSITY." Solar-Terrestrial Physics 5, no. 4 (December 17, 2019): 10–20. http://dx.doi.org/10.12737/stp-54201902.

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This paper provides insight into heliospheric processes and galactic cosmic ray (GCR) modulation occurring due to the presence of two branches of solar activity in this solar layer. According to the topology of solar magnetic fields, these branches are called toroidal (active regions, sunspots, flares, coronal mass ejections, etc.) and poloidal (high-latitude magnetic fields, polar coronal holes, zonal unipolar magnetic regions, etc.). The main cause of different manifestations of the two branches on the solar surface and in the heliosphere — the layer at the base of the heliosphere in which the main energetic factor is the magnetic field — is formulated. In this case, the magnetic fields of the poloidal branch, which have a larger scale but a lower intensity, gain an advantage in penetrating into the heliosphere. A connection is shown between the poloidal branch and the heliospheric characteristics (solar wind velocity field, size of the heliosphere, form of the heliospheric current sheet, regular heliospheric magnetic field and its fluctuations) that, according to modern notions, determine GCR propagation in the heliosphere.
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Fernandez, Abyan Arief, Andrian Rakhmatsyah, and Aulia Arif Wardana. "Monitoring Floating Solar Tracker Based on Axis Coordinates using LoRa Network." International Journal of Renewable Energy Development 9, no. 2 (February 3, 2020): 141–49. http://dx.doi.org/10.14710/ijred.9.2.141-149.

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This research aimed to build a solar tracker for a floating solar panel and used long–range (LoRa) communication to harvest energy and monitor its process. With the rising demand for renewable energy in these recent years especially for solar energy, it needs to meet this demand to remain relevant for the upcoming years where it will have an even larger impact as we shift into clean energy. Monitoring single–axis solar trackers on rural areas difficult and cost–intensive. The purpose of a floating solar farm is to reduce the cost from buying/renting land. Floating solar panels cannot be monitored using wired because they are moving nodes in the water, it makes wired installation complicated. Hence, using wireless sensornetwork is a solution that allowsremote monitoring of floating solar panels in rural areas and makes moving nodes mentioned above possible. Testing wasperformed by sending 100 packets from the node to its gateway using LoRa modulation, and the gateway successfully received about 90% of the packets sent by the node. The vertical single-axis solar tracker used in floating solar managed to get 17% more energy than the fixed solar with a more stable income for the whole duration of sending 100 packets.©2020. CBIORE-IJRED. All rights reserved
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Ciubotaru, Ramona Mihaela, Pietro Franceschi, Luca Zulini, Marco Stefanini, Domen Škrab, Marcia Denise Rossarolla, Peter Robatscher, Michael Oberhuber, Urska Vrhovsek, and Giulia Chitarrini. "Mono-Locus and Pyramided Resistant Grapevine Cultivars Reveal Early Putative Biomarkers Upon Artificial Inoculation With Plasmopara viticola." Frontiers in Plant Science 12 (July 1, 2021). http://dx.doi.org/10.3389/fpls.2021.693887.

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One of the most economically important grapevine diseases is Downy mildew (DM) caused by the oomycete Plasmopara viticola. A strategy to reduce the use of fungicides to compensate for the high susceptibility of V. vinifera is the selection of grapevine varieties showing pathogen-specific resistance. We applied a metabolomics approach to evaluate the metabolic modulation in mono-locus resistant genotypes carrying one locus associated with P. viticola resistance (Rpv) (BC4- Rpv1, Bianca- Rpv3-1, F12P160- Rpv12, Solaris- Rpv10), as well as in pyramided resistant genotypes carrying more than one Rpv (F12P60- Rpv3-1; Rpv12 and F12P127- Rpv3-1, Rpv3-3; Rpv10) taking as a reference the susceptible genotype Pinot Noir. In order to understand if different sources of resistance are associated with different degrees of resistance and, implicitly, with different responses to the pathogen, we considered the most important classes of plant metabolite primary compounds, lipids, phenols and volatile organic compounds at 0, 12, 48, and 96 h post-artificial inoculation (hpi). We identified 264 modulated compounds; among these, 22 metabolites were found accumulated in significant quantities in the resistant cultivars compared to Pinot Noir. In mono-locus genotypes, the highest modulation of the metabolites was noticed at 48 and 96 hpi, except for Solaris, that showed a behavior similar to the pyramided genotypes in which the changes started to occur as early as 12 hpi. Bianca, Solaris and F12P60 showed the highest number of interesting compounds accumulated after the artificial infection and with a putative effect against the pathogen. In contrast, Pinot Noir showed a less effective defense response in containing DM growth.
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Dissertations / Theses on the topic "Modulation solaire"

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Ghelfi, Alexandre. "Analyse des données de l'expérience AMS-02 pour la propagation du rayonnement cosmique dans la cavité solaire et la Galaxie." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY044/document.

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Le rayonnement cosmique, mis en évidence par Viktor Hess en 1912, est composé de particules chargées, créées et possiblement accélérées dans les restes de supernova, et qui se propagent dans la Galaxie. La mesure des flux du rayonnement cosmique permet de mettre des contraintes sur leurs sources et leur transport, mais aussi de se pencher sur le problème de la matière sombre.C'est pour répondre à ces questions qu'a été construit le détecteur AMS-02, mis en place sur la station spatiale internationale depuis mai 2011. Ce détecteur de haute précision mesure l'ensemble des flux de particules du rayonnement cosmique.Le travail proposé dans cette thèse consiste à estimer le flux de protons avec le détecteur AMS-02. L'accent est mis sur la déconvolution des effets de la réponse en énergie du détecteur sur les flux et sur la caractérisation du flux obtenu à haute énergie (au-dessus de 200 GeV/n) avec la mise en évidence d'une cassure spectrale.D'autre part, le soleil émet un plasma qui interagit avec les particules du rayonnement cosmique, modifiant les flux issus de la propagation dans la Galaxie. Cette modification évolue dans le temps en suivant le cycle d'activité solaire et est appelée modulation solaire. Dans ce cadre, nous avons obtenu une nouvelle détermination robuste des flux interstellaires de protons et d'hélium en nous basant sur les données récentes du rayonnement cosmique (incluant AMS-02). Les niveaux de modulation solaire obtenus sont validés avec une seconde analyse réalisée à partir des données des moniteurs à neutrons, détecteurs au sol, qui permettent d'établir des séries en temps du paramètre de modulation depuis les années 50
Cosmic rays (CR) were discovered by Viktor Hess in 1912. Charged CR are synthesized and supposedly accelerated in supernova remnants, then propagate through the Galaxy. CR flux measurement set constraints on CR sources and propagation, but may also bring answers to the dark matter problem.AMS-02 is a high precision particle physics detector placed on the international space station since may 2011. It measures the CR fluxes of many species.This thesis deals with the proton flux estimation measured by the AMS-02 instrument. The focus is set on the unfolding of the instrument energy response impacting the flux, and on the caracterisation of the high-energy spectral break.The Sun produces a plasma which interacts with CR particles, modifying the flux obtained from galactic propagation. This modification evolves through time following the solar activity cycle, and is denoted solar modulation. In this framework, decolving from this effect, a robust determination of the proton and helium interstellar fluxes is obtained using recent high precision CR data including AMS-02. The associated solar modulation levels are cross-checked with a second estimation taken from neutron monitors (ground based detectors) data, allowing solar modulation time series reconstruction from the 50s
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Boumier, Patrick. "Developpement instrumental pour l'etude des oscillations solaires globales : evaluation et tests des performances de l'experience golf/soho reduction du bruit solaire basse frequence par une technique de modulation (mesure croisee)." Paris 7, 1991. http://www.theses.fr/1991PA077141.

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Au cours des 3 dernieres decennies, l'heliosismologie s'est revelee un puissant outil d'investigation de la structure interne du soleil, constituant ainsi le plus grand espoir de tester les modeles d'evolution de l'etoile, et en particulier de resoudre l'enigme des neutrinos. Les spectrometres a resonance permettent d'estimer la vitesse des couches solaires par la mesure du decalage doppler de raies d'absorption. Dans le cas d'observation du disque solaire integre, les fluctuations des profils de raie locaux (dans les regions actives par exemple) contribuent pour une part importante au bruit solaire, notamment dans le domaine des basses frequences ou l'existence des modes de gravite est la plus probable. Afin de reduire cette composante de bruit, le spectrometre golf, embarque a bord de la sonde soho en 1995, permettra une mesure en 4 points dans les raies d1 et d2 du sodium, au lieu de 2 habituellement. Une partie de la these est consacree a l'etude des specifications scientifiques de golf. Le transfert du rayonnement dans la cellule a resonance, cur de la detection, est simule, et quelques tests instrumentaux sont presentes. Deux types de contraintes instrumentales sont etablis, selon les proprietes spectrales des sources de bruit, et les stabilites requises sont estimees. L'autre partie de la these est relative aux resultats de la premiere maquette de golf. Les variations des pentes des profils de raie sont etudiees, et une nouvelle technique d'analyse des oscillations solaires est developpee. Une reduction significative du bruit solaire par rapport aux mesures en 2 points est obtenue pour les periodes d'oscillations superieures a 1 heure
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Godfroy, Maxime. "Modulation des propriétés optoélectroniques de colorants organiques pour des applications en cellules photovoltaïques hybrides." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV031.

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En une heure, la Terre reçoit en énergie solaire l’équivalent d’une année de consommation énergétique mondiale. Pour cette raison, les cellules photovoltaïques qui convertissent des photons en électricité, ont un rôle déterminant à jouer dans la transition énergétique imposée par les changements climatiques. Les cellules solaires sensibilisées par des colorants sont une des technologies émergentes qui ont déjà été utilisées à l’échelle industrielle à travers quelques exemples d’intégration aux bâtiments. Elles représentent une alternative esthétique et peu cher comparée aux cellules à silicium. Ces cellules hybrides dites de « Grätzel » utilisent un semi-conducteur inorganique nanostructuré sur lequel est greffé un colorant qui à l’état photo-excité va injecter des électrons dans l’oxyde. Ce sensibilisateur va être régénéré par un couple redox présent dans un électrolyte ou un transporteur de trous moléculaire qui eux-mêmes vont être régénérés à la contre-électrode. Dans ce contexte, ce travail présente les études réalisées sur certains constituants de la cellule (du semi-conducteur jusqu’au système régénérateur du colorant). La majeure partie de cette thèse concerne la synthèse et la caractérisation avancée de nouveaux semi-conducteurs organiques, des colorants ou des transporteurs de trous moléculaires, et l’étude des relations structure/propriétés. En particulier, le remplacement, la substitution ou la rigidification de groupements présents dans ces structures ont été réalisés et leur influence sur les propriétés des nouvelles molécules a été étudiée. Les colorants synthétisés présentent des maxima de la bande d’absorption à plus faible énergie allant de 440 nm à 610 nm. Les niveaux d’énergie de ces nouveaux matériaux organiques ont été déterminés par voltammétrie cyclique et également calculés et localisés par la chimie quantique. Certains composés ont été étudiés par diffraction des rayons X, par analyse thermogravimétrique ou par calorimétrie différentielle à balayage. Après une complète caractérisation, ces matériaux ont été intégrés dans des dispositifs photovoltaïques à colorants en utilisant un électrolyte liquide pour atteindre des efficacités élevées jusqu’à 9,78 % en utilisant un seul colorant et jusqu’à 10,90 % dans le cas de la co-sensibilisation du TiO2 par deux sensibilisateurs. Certains colorants ont également conduit à des efficacités se situant à l’état de l’art à 7,81 % en remplaçant l’électrolyte liquide par un liquide ionique. De plus, certains colorants dans ces mêmes dispositifs ont présenté une excellente stabilité avec une perte comprise entre 7 et 38 % après 7000 heures d’illumination continue à 1000 W.m-2 à 65 °C. Enfin, des premiers tests ont également été réalisés en dispositifs à l’état solide qui ont conduit à une efficacité 4,5 % avec un transporteur de trous de référence ouvrant de nouvelles perspectives d’application après optimisations. En parallèle, les nouveaux transporteurs de trous synthétisés dans ce travail se sont révélés efficaces en cellules à base de pérovskites
During one hour, the Earth receives solar energy which is equivalent to one year of the world energy consumption. For this reason, photovoltaic cells that convert photons to electricity, have a key role to play in the energetic transition imposed by climate change. Dye-sensitized solar cells are one of the emergent technologies that have already been used at the industrial scale in a few examples of building integrating. They represent an esthetic and low-cost alternative compared to silicon solar cells. These hybrid cells also named « Grätzel cells » use a nanostructured inorganic semi-conductor where a dye is grafted onto the surface and acts as a sensitizer. This dye injects electrons after photo-excitation in the oxide. The dye is regenerated by a redox couple present in a liquid electrolyte or a hole transport material that are themselves regenerated by the counter electrode. In this context, this work presents studies about some of the cell constituents (from the semi-conductor to the dye regenerating system). The major part of this thesis concerns the synthesis and the advanced characterization of organic semi-conductors, dyes or hole transport materials, and the study of the structure/properties relations. In particular, the replacement, the substitution, or the rigidification of some functional groups in these structures were achieved and their influence on the properties of the new molecules were studied. The synthesized dyes present maxima of the absorption band at the lowest energy between 440 nm and 610 nm. Energy levels of the new organic materials were determined by cyclic voltammetry and also calculated and localized using the quantum chemistry. Some of the compounds were studied by X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry. After a complete characterization, these materials were integrated in dye-sensitized photovoltaic devices using a liquid electrolyte to achieve high efficiencies up to 9,78 % using a single dye and up to 10,90 % in the case of the co-sensitization of TiO2 with two dyes. Certain dyes have demonstrated state-of-the-art efficiencies at 7,81 % by replacing the liquid electrolyte by an ionic liquid electrolyte. Moreover, the use of some of the dyes in these last devices was carried out and found to have an excellent stability with a loss of initial efficiency included between 7 % and 38 % after 7000 hours of continuous illumination at 1000 W.m-2 at 65 °C. Finally, first tests were also realized in solid state devices that showed an efficiency of 4,5 % with a reference hole transport material opening new application perspectives after optimizations. In parallel, the new synthesized hole transport materials in this work were effective in perovskite-based cells
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Manecki, Szymon M. "Annual Modulation Measurement of the Low Energy Solar Neutrino Flux with the Borexino Detector." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23250.

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This work reports a first attempt to measure the solar neutrino annual
flux modulation due to Earth\'s elliptical orbit with the Borexino detector. Borexino is a real-time calorimetric detector for low energy neutrino spectroscopy located in the underground laboratory of Gran Sasso, Italy. The experiment\'s main focus is the direct measurement of the 7Be solar neutrino flux of all flavors via neutrino-electron scattering in an ultra-pure scintillation liquid. The original goal of this work was to quantify sensitivity of the Borexino detector to a 7% peak-to-peak signal variation over the course of a year and study background stability. A Monte-Carlo simulated sample of the expected variation was prepared in two phases of data acquisition, Phase I that spans from May-2007 to May-2010 and Phase II from October-2011 to September-2012. The data was then fitted in the time domain with a sinusoidal function and analyzed with the Lomb-Scargle fast Fourier transformation in the search for significant periodicities between periods of 0.5 and 1.5 years. The search was performed in the energy window dominated by 7Be, [210; 760] keV, and 60-day bins in the case of the fit and 10-bins for the Lomb-Scargle scan. This work also contains study of the post-purification data of Phase II beyond September-2012 with a prediction for the future sensitivity and justification of the achieved background levels.
Ph. D.
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Manuel, Rex. "Time-dependent modulation of cosmic rays in the outer heliosphere / Rex Manuel." Thesis, North-West University, 2013. http://hdl.handle.net/10394/8740.

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The time-dependent modulation of galactic cosmic rays in the heliosphere is studied by computing intensities using a two-dimensional, time-dependent modulation model. The compound approach of Ferreira and Potgieter (2004), which describes changes in the cosmic ray transport coefficients over a solar cycle, is improved by introducing recent theoretical advances in the model. Computed intensities are compared with Voyager 1 and 2, IMP 8 and Ulysses proton observations in search of compatibility. It is shown that this approach gives realistic cosmic ray proton intensities on a global scale at Earth and along both Voyager spacecraft trajectories. The results show that cosmic ray modulation, in particular during the present polarity cycle, is not just determined by changes in the drift coefficient but is also dependent on changes in the diffusion coefficients. Furthermore, a comparison of computations to observations along the Voyager 1 and Voyager 2 trajectories illustrates that the heliosphere is asymmetrical. Assuming the latter, E > 70 MeV and 133-242 MeV cosmic ray proton intensities along Voyager 1 and 2 trajectories are predicted from 2012 onwards. It is shown that the computed intensities along Voyager 1 can increase with an almost constant rate since the spacecraft is close to the heliopause. However, the model shows that Voyager 2 is still under the influence of temporal solar activity changes because of the relatively large distance to the heliopause when compared to Voyager 1. Along the Voyager 2 trajectory the intensities should remain generally constant for the next few years and then should start to steadily increase. It is also found that without knowing the exact location of heliopause and transport parameters one cannot conclude anything about local interstellar spectra. The effect of a dynamic inner heliosheath width on cosmic ray modulation is also studied by implementing a time-dependent termination shock position in the model. This does not lead to improved compatibility with spacecraft observations so that a time-dependent termination shock along with a time-dependent heliopause position is required. The variation of the heliopause position over a solar cycle is found to be smaller compared to that of the termination shock. The model predicts the heliopause and termination shock positions along Voyager 1 in 2012 at 119 AU and 88 AU respectively and along Voyager 2 at 100 AU and 84 AU respectively.
Thesis (PhD (Space Physics))--North-West University, Potchefstroom Campus, 2013
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Magidimisha, Edwin. "A study of the time-dependent modulation of cosmic rays in the inner heliosphere / E. Magidimisha." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4402.

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A two-dimensional (2-D) time-dependent cosmic ray modulation model is used to calculate the modulation of cosmic-ray protons and electrons for 11-and 22-year modulation cycles using a compound approach to describe solar cycle related changes in the transport parameters. The compound approach was developed by Ferreira and Potgieter (2004) and incorporates the concept of propagation diffusion barriers, global changes in the magnetic field, time-dependent gradient, curvature and current-sheet drifts, and other basic modulation mechanisms. By comparing model results with 2.5 GV Ulysses observations, for both protons and electrons, it is shown that the compound approach results in computed intensities on a global scale compatible to observations. The model also computes the expected latitudinal dependence, as measured by the Ulysses spacecraft, for both protons and electrons. This is especially highlighted when computed intensities are compared to observations for the different fast latitude scan (FLS) periods. For cosmic ray protons a significant latitude dependence was observed for the first FLS period which corresponded to solar minimum conditions. For the second, which corresponded to solar maximum, no latitude dependence was observed as was the case for the third FLS period, which again corresponded to moderate to minimum solar activity. For the electrons the opposite occurred with only an observable latitude dependence in intensities for the third FLS period. It is shown that the model results in compatible intensities when compared to observations for these periods. Due to the success of the compound approach, it is also possible to compute charge-sign dependent modulation for 2.5 GV protons and electrons. The electron to proton ratio is presented at Earth and along the Ulysses trajectory. Lastly, it is also shown how the modulation amplitude between solar minimum and maximum depends on rigidity. This is investigated by computing cosmic ray intensities for both protons and electrons, not only at 2:5 GV, but also up to 7:5 GV. A refinement for the compound approach at higher rigidities is proposed.
Thesis (M.Sc. (Space Physics))--North-West University, Potchefstroom Campus, 2011.
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Hofverberg, Petter. "A New Measurement of Low Energy Antiprotons In the Cosmic Radiation." Doctoral thesis, Stockholm : Fysik, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9427.

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Soukharev, Boris E., and Lon L. Hood. "Possible solar modulation of the equatorial quasi-biennial oscillation: Additional statistical evidence." AMER GEOPHYSICAL UNION, 2001. http://hdl.handle.net/10150/624003.

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Although the quasi-biennial oscillation (QBO) in the equatorial zonal wind is dominantly driven by wave forcing originating in the troposphere, a recent study suggests that certain properties of the QBO may vary slightly on the 11-year solar cycle timescale [Salby and Callaghan, 2000]. Here we report further statistical investigation using both equatorial wind data for levels from 50 to 1 hPa and longterm proxy solar ultraviolet flux time series (10.7-cm solar radio flux and sunspot numbers). Spectral analysis of the solar time series yields evidence for a significant spectral peak at periods between 25 and 30 months, approximately equivalent to the mean QBO period, as had also been noted by earlier authors [Shapiro and Ward, 1962]. Cross-spectral analysis of the 10.7-cm solar radio flux and equatorial zonal wind time series shows significant coherency at the QBO period at all available pressure levels. The phase lag of the wind data relative to the solar flux at the QBO period ranges from 0–1 months near the stratopause (1 hPa) to 20–24 months in the lower stratosphere (50 hPa). The nearly inphase relationship near the stratopause suggests a possible modulation of the QBO at this level by the radiative and photochemical effects of solar ultraviolet variations. The amplitudes of the solar variations at the QBO period tend to be larger under solar maximum than under solar minimum conditions. Composite analysis of the westerly and easterly phases of the equatorial zonal wind shows subtle but consistent differences in the durations of the westerlies and easterlies between solar maximum and minimum conditions.
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Hood, Lon L. "QBO/solar modulation of the boreal winter Madden-Julian oscillation: A prediction for the coming solar minimum." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/624342.

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The Madden-Julian oscillation (MJO), also known as the 30-60day oscillation, is the strongest of the intraseasonal climate oscillations in the tropics and has significant derivative effects on extratropical circulation and intraseasonal climate. It has recently been shown that the stratospheric quasi-biennial oscillation (QBO) modulates the amplitude of the boreal winter MJO such that MJO amplitudes are larger on average during the easterly phase (QBOE) than during the westerly phase (QBOW). A major possible mechanism is the decrease in static stability in the lowermost stratosphere under QBOE conditions resulting from relative upwelling associated with the QBO-induced meridional circulation. Here evidence is presented that tropical upwelling changes related to the 11year solar cycle also modulate the boreal winter MJO. Based on 37.3years of MJO amplitude data, the largest amplitudes and occurrence rates, and the weakest static stabilities in the tropical lower stratosphere, occur during the QBOE phase under solar minimum (SMIN) conditions while the smallest amplitudes and strongest static stabilities occur during the QBOW phase under solar maximum (SMAX) conditions. Conversely, when the QBO and solar forcings are opposed (QBOW/SMIN and QBOE/SMAX), the difference in occurrence rates becomes statistically insignificant. During the coming solar minimum, at least one additional winter in the QBOE/SMIN category should occur (possibly as early as 2017/2018) during which especially large MJO amplitudes are expected and an initial test of these results will be possible. Plain Language Summary An ongoing issue in climate science is the extent to which upper atmospheric processes, including solar forcing, can influence tropospheric climate. It has recently been shown that an internal oscillation of the stratosphere, the quasi-biennial oscillation, can modulate the amplitude and occurrence rate of intraseasonal climate oscillations in the tropical Pacific during northern winter. These intraseasonal oscillations, the most important of which is the 30-60day Madden-Julian oscillation, have significant derivative effects on climate outside of the tropics, including impacts on rainfall events over the continental United States. Here evidence is presented that the amplitude of the Madden-Julian oscillation during northern winter is also modulated by the 11year solar cycle. The modulation is such that amplitudes and occurrence rates are largest under solar minimum conditions when the quasi-biennial oscillation is in its easterly phase and smallest under solar maximum conditions when the quasi-biennial oscillation is in its westerly phase. However, the available time record (37.3years of satellite measurements) is limited. During the coming solar minimum, at least one additional winter in the solar minimum/easterly category should occur (possibly as early as 2017/2018) during which larger-than-average amplitudes are expected and an initial test of the proposed relationship will be possible.
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Baltagi, Youssef. "Spectroscopis de modulation optique : développement d'un ensemble expérimental et application à la caractérisation de matériaux et d'hétérostructures du système GaInAs/AIInAs épitaxié sur InP." Lyon, INSA, 1995. http://www.theses.fr/1995ISAL0096.

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Dans ce travail, nous étudions les propriétés optiques d'hétérostructures III-V par spectroscopie de modulation optique. En particulier, nous nous intéressons au système GaInAs /AlInAs. Dans un premier temps, nous avons développé un ensemble expérimental sensible travaillant dans la gamme 0. 6-1. 8 micromètres et pour des températures variant de 8K à 600K. Nous avons également montré la faisabilité d'un prototype de photoréflectivimètre compact et performant. Nous avons, caractérisé des couches simples d'AlInAs / InP. La réponse de photoréflectivité (PR) nous a permis de mettre en évidence une modulation de composition ainsi et un effet de localisation dans AlInAs. En outre, nous avons déterminé les propriétés fondamentales de puits quantiques de GaInAs / AlInAs : détermination de la discontinuité de bande, qualité des interfaces et du materiau. Enfin, nous avons appliqué cette technique à la mesure de la position du niveau de Fermi de surface dans des structures de type UN+ (couche non dopée / couche dopée n+) AlInAs. Les mêmes types de structures ont été élaborées afin de mesurer le champ piézoélectrique dans un puits contraint de GaInAs / GaAs épitaxié sur un substrat polaire
In this work, we study using modulation spectroscopy the optical properties of III-V semiconductor compounds, especially InAlAs / InGaAs based structures. The first part of the work deals with the development of an experimental set up, whose sensitivity is 10-6. This system works between 8K and 600K, in the spectral range 0. 6 to-1. 8 micrometer. In this part we also show the feasibility of a performing prototype. The second part deals with the characterization of bulk InAlAs / InP layers. Using the temperature dependence of the Photore-flectance (PR) spectra we show the existence of a localization in the InAlAs layer due to some clustering effect. Furthennore, we have studied InGaAs/InAlAs single quantum wells. The PR technique is shown to be a powerful tool to characterize the interface and material quality, interface roughness…, and to give a qualitative determination of conduction band offset in this system. In the last part of this work, we apply the PR in order to measure the surface Fermi level in an InAlAs UN+ ( undoped layer grown on a heavily doped n+ layer) structure. The same structures have been used to measure the piezoelectric field in a InGaAs/GaAs strained SQW grown on a polar <111> GaAs substrate
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Books on the topic "Modulation solaire"

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Usoskin, Ilya G. Solar activity changes and modulation of cosmic rays. Oulu: University of Oulu, 2000.

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Book chapters on the topic "Modulation solaire"

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Cummings, A. C., and E. C. Stone. "Anomalous Cosmic Rays and Solar Modulation." In Cosmic Rays in the Heliosphere, 51–62. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-017-1189-0_5.

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Hernández-Prieto, Miguel A., and Min Chen. "Light Harvesting Modulation in Photosynthetic Organisms." In Photosynthesis: Molecular Approaches to Solar Energy Conversion, 223–46. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67407-6_8.

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Perko, John S. "Solar-Cycle Modulation of Galactic Cosmic Rays." In Genesis and Propagation of Cosmic Rays, 315–23. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-4025-3_20.

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Heber, B., and R. A. Burger. "Modulation of Galactic Cosmic Rays at Solar Minimum." In Space Sciences Series of ISSI, 125–38. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-017-1179-1_10.

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Frasca, A., S. Catalano, and E. Marilli. "Rotational Modulation of Hα Emission in RS CVN Systems." In Magnetodynamic Phenomena in the Solar Atmosphere, 475–76. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0315-9_103.

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Heber, B., and R. G. Marsden. "Cosmic Ray Modulation Over the Poles at Solar Maximum: Observations." In The 3-D Heliosphere at Solar Maximum, 309–19. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-3230-7_50.

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McDonald, F. B., Z. Fujii, P. Ferrando, B. Heber, A. Raviart, H. Kunow, N. Lal, et al. "The Onset of Long Term Modulation in the Heliosphere in Cycle 23." In The 3-D Heliosphere at Solar Maximum, 321–25. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-3230-7_51.

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Peristykh, Alexei N., and Paul E. Damon. "Modulation of Atmospheric 14C Concentration by the Solar Wind and Irradiance Components of the Hale and Schwabe Solar Cycles." In Solar Electromagnetic Radiation Study for Solar Cycle 22, 343–55. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5000-2_30.

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Wibberenz, G., H. V. Cane, I. G. Richardson, and T. T. Von Rosenvinge. "The Influence of Tilt Angle and Magnetic Field Variations on Cosmic Ray Modulation." In The 3-D Heliosphere at Solar Maximum, 343–47. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-3230-7_55.

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Cliver, E. W., I. G. Richardson, and A. G. Ling. "Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation." In Cosmic Rays in the Heliosphere, 3–19. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-9200-9_2.

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Conference papers on the topic "Modulation solaire"

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Bobik, P., M. J. Boschini, S. Delia Torre, M. Gervasi, D. Grandi, K. Kudela, G. La Vacca, et al. "Solar Modulation along last solar minimum." In International Conference on Advanced Technology and Particle Physics. WORLD SCIENTIFIC, 2014. http://dx.doi.org/10.1142/9789814603164_0027.

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Cane, H. V., G. Wibberenz, and I. G. Richardson. "Solar magnetic field variations and cosmic ray modulation." In The solar wind nine conference. AIP, 1999. http://dx.doi.org/10.1063/1.58653.

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Yanchukovsky, Valery L., and Anastasiya Yu Belinskaya. "Distribution of the number of strong earthquakes and the intensity of space rays during the solar activity cycle." In Недропользование. Горное дело. Направления и технологии поиска, разведки и разработки месторождений полезных ископаемых. Экономика. Геоэкология. Федеральное государственное бюджетное учреждение науки Институт нефтегазовой геологии и геофизики им. А.А. Трофимука Сибирского отделения Российской академии наук, 2020. http://dx.doi.org/10.18303/b978-5-4262-0102-6-2020-083.

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The relationship of Earth's seismicity with solar activity is investigated using the results of continuous long–term observations of cosmic ray intensity, solar activity and the number of strong earthquakes. Modulation of the flux of cosmic rays is used as information on the level of solar activity, processes on the Sun and interplanetary medium. The distribution of the number of sunspots, the intensity of cosmic rays and the number of strong earthquakes in the solar cycle is presented.
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Luo, X., M. Zhang, M. S. Potgieter, X. Feng, and N. V. Pogorelov. "Study cosmic ray modulation near the heliopause: A numerical approach." In SOLAR WIND 14: Proceedings of the Fourteenth International Solar Wind Conference. AIP Publishing LLC, 2016. http://dx.doi.org/10.1063/1.4943842.

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Ahluwalia, H. S., and R. C. Ygbuhay. "The descent of the solar cycle 24 cosmic ray modulation." In SOLAR WIND 13: Proceedings of the Thirteenth International Solar Wind Conference. AIP, 2013. http://dx.doi.org/10.1063/1.4811054.

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Huang, Haiying, and Yayu Hew. "Wireless Vibration Sensing Without a Battery." In ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8206.

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This paper presents the implementation and characterization of a low power wireless vibration sensor that can be powered by a flash light. The wireless system consists of two components, namely the wireless sensor node and the wireless interrogation unit. The wireless sensor node includes a wireless strain gauge that consumes around 6 mW, a signal modulation circuit, and a light energy harvesting unit. To achieve ultra-low power consumption, the signal modulation circuit was implemented using a voltage-controlled oscillator (VCO) to convert the strain gauge output to an intermediate frequency (IF) signal, which is then used to alter the impedance of the sensor antenna and thus achieves amplitude modulation of the backscattered antenna signal. A generic solar panel with energy harvesting circuit is used to power the strain sensor node continuously. The wireless interrogation unit transmits the interrogation signal and receives the amplitude modulated antenna backscattering, which can be down-converted to recover the IF signal. In order to measure the strains dynamically, a Phase Lock Loop (PLL) circuit was implemented at the interrogator to track the frequency of the IF signal and provide a signal that is directly proportional to the measured strain. The system features ultra-low power consumption, complete wireless sensing, solar powering, and portability. The application of this low power wireless strain system for vibration measurement is demonstrated and characterized.
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Parhi, S. "Sensitivity of Cosmic Ray Modulation to an Outer Scale of Turbulence." In SOLAR WIND TEN: Proceedings of the Tenth International Solar Wind Conference. AIP, 2003. http://dx.doi.org/10.1063/1.1618580.

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Kudryavtsev, I. V., and V. A. Dergachev. "RADIOCARBON PRODUCTION RATE, HELIOSPHERIC MODULATION POTENTIAL AND CLIMATE VARIATIONS DURING THE MIDDLE HOLOCENE." In All-Russia Conference on Solar and Solar-Terrestrial Physics. The Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 2020. http://dx.doi.org/10.31725/0552-5829-2020-185-188.

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Ahluwalia, H. S., R. C. Ygbuhay, M. Maksimovic, K. Issautier, N. Meyer-Vernet, M. Moncuquet, and F. Pantellini. "Status Of Galactic Cosmic Ray Recovery From Sunspot Cycle 23 Modulation." In TWELFTH INTERNATIONAL SOLAR WIND CONFERENCE. AIP, 2010. http://dx.doi.org/10.1063/1.3395964.

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Vasiliev, S. S., and V. A. Dergachev. "SOLAR MODULATION POTENTIAL ACCORDING TO DATA ON COSMOGENIC ISOTOPES OVER THE PAST 10 THOUSAND YEARS." In All-Russia Conference on Solar and Solar-Terrestrial Physics. The Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 2018. http://dx.doi.org/10.31725/0552-5829-2018-87-90.

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Reports on the topic "Modulation solaire"

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Moskalenko, Igor V., Troy A. Porter, and Seth W. Digel. Inverse Compton Scattering on Solar Photons, Heliospheric Modulation, and Neutrino Astrophysics. Office of Scientific and Technical Information (OSTI), August 2006. http://dx.doi.org/10.2172/888780.

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Behne, Patrick Alan. DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation. Office of Scientific and Technical Information (OSTI), August 2016. http://dx.doi.org/10.2172/1296694.

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Cliver, E. W., I. G. Richardson, and A. G. Ling. Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation (PostPrint). Fort Belvoir, VA: Defense Technical Information Center, March 2012. http://dx.doi.org/10.21236/ada561709.

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