New class of N-dimensional braneworlds

The new class of the non-stationary solutions to the system of N-dimensional equations for coupled gravitational and massless scalar field is found. The model represents a single (N-1)-brane in a space-time with one large (infinite) and (N-5) small (compact) space-like extra dimensions. In some particular cases the model corresponds to the gravitational and scalar field standing waves bounded by the brane. These braneworlds can be relevant in string and other higher dimensional models.     

Addressing selectivity criteria in binding equilibria

Chemical systems, in particular those involving biological and environmental backgrounds, develop through selective processes which are determined by multiple equilibria. Several methods that have been developed to assess thermodynamic selectivity in binding equilibria, including the analysis of selectivity coefficients, the use of calculated species distribution diagrams, selectivity diagrams, and conditional stability constants, are reviewed in this paper with reference to examples mainly related to chemical systems of biological and/or environmental concern. Also the concept of binding affinity has been dealt with, since binding selectivity in equilibrium systems relates to the different affinities with which chemical species bind to each other.     

A New Approach to Equations with Memory

We discuss a novel approach to the mathematical analysis of equations with memory, based on a new notion of state. This is the initial configuration of the system at time t = 0 which can be unambiguously determined by the knowledge of the dynamics for positive times. As a model, for a nonincreasing convex function ${G : \mathbb{R}^+ \to \mathbb{R}^+}We discuss a novel approach to the mathematical analysis of equations with memory, based on a new notion of state. This is the initial configuration of the system at time t = 0 which can be unambiguously determined by the knowledge of the dynamics for positive times. As a model, for a nonincreasing convex function G : \mathbbR⁺ ? \mathbbR⁺{G : \mathbb{R}^+ \to \mathbb{R}^+} such that

$G(0) = \lim_{s\to 0}G(s) > \lim_{s\to\infty}G(s) >0 $G(0) = \lim_{s\to 0}G(s) > \lim_{s\to\infty}G(s) >0      94. Controlled dumping of pulses of laser radiation ranging from MIR to the MM by means of optical semiconductor switching      S. Marchetti  M. Martinelli  R. Simili  M. Giorgi  R. Fantoni 《Applied physics. B, Lasers and optics》2001,72(8):927-930 A simple method to produce sub-ns pulses of laser radiation with wavelength ranging from middle infrared (MIR) to millimeter (MM) is experimentally demonstrated. The system operates with a single OSS (optical semiconductor switching) driven by a ns Nd laser. Pulse control is produced by varying the distance of a mirror from an OSS used as a cavity dumping. The effectiveness of this sub-ns MM pulse generation is larger than the one observed in other schemes. Pulses with 500-ps FWHM and 15-W power were produced at 2.65 mm with a time compression compared to the 2-ns FWHM of the 1.06-μm driving laser. Received: 30 October 2000 / Revised version: 26 January 2001 / Published online: 9 May 2001      95. Development and simulation results of a sparsification and readout circuit for wide pixel matrices      A. GabrielliF. Giorgi  F. MorsaniM. Villa 《Nuclear Physics B - Proceedings Supplements》2011,215(1):307-309       96. Bounds and monotonicity for the generalized Robin problem      Tiziana Giorgi  Robert Smits 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2008,59(4):600-618 We consider the principal eigenvalue λ 1Ω(α) corresponding to Δu = λ (α) u in on ∂Ω, with α a fixed real, and a C 0,1 bounded domain. If α > 0 and small, we derive bounds for λ 1Ω(α) in terms of a Stekloff-type eigenvalue; while for α > 0 large we study the behavior of its growth in terms of maximum curvature. We analyze how domain monotonicity of the principal eigenvalue depends on the geometry of the domain, and prove that domains which exhibit domain monotonicity for every α are calibrable. We conjecture that a domain has the domain monotonicity property for some α if and only if it is calibrable. Robert Smits: This author was partially supported by a grant of the National Security Agency, grant #H98230-05-1-0060.      97. Parametric study of a ramanp-H2 laser with over 30 MW emission at 16 μm      M. Bernardini  A. Ferrario  M. Giorgi  S. Marchetti  A. Palucci 《Il Nuovo Cimento D》1984,4(6):520-528 Summary In this work the main parameters which define the threshold, the temporal shape and the stability ofp-H2 Raman laser have been investigated. Our results show a very high-power conversion efficiency (130%) and for each pump CO2 line we can dispose of a correspondent line (pulse≥1J/50 ns) in the 16 μm range. This is foundamental as far as UF6 isotopic separation is concerned. Riassunto In questo lavoro sono stati studiati i principali parametri che definiscono la soglia, la forma temporale e la stabilità di un laser Raman a para-idrogeno (16 μm). I nostri risultati mostrano un'alta efficienza di conversione di potenza (130%) per ciascuna riga del laser a CO2 permettendo una buona tunabilità nel range dei 16 μm. Questo è fondamentale per la separazione isotopica di UF6. Резюме В этой работе исследуются основные параметры, которые определяют порог, временную форму и стабильностьp-H2 рамановского лазера. Наши результаты показывают очень высокую эффективность конверсии (130%). Для каждой линии CO2 накачки мы можем сопоставить соответствующую линию (импульс≥1 Дж/50 нс) в диапазоне 16 мкм. Это является основой для разделения изотопов UF6.       98. High efficiency long pulse FIR Raman conversion in ammonia      M. Bernardini  F. D''Amato  M. Giorgi  S. Marchetti 《International Journal of Infrared and Millimeter Waves》1989,10(1):31-41 Generally the quantum efficiency of FIR Raman generation in molecular gases is below the theoretical value. This disagreement is particularly evident in Raman scattering from pulsed sources with short pulse length, when the vibrational saturation limits the power conversion. Other nonlinear processes can overcome this saturation, but they require a very intense pump power for too short a time to use the FIR radiation in high sensitive experiments with heterodyne detection. This is the case, for instance, of RFWM. In this work we describe the experimental conditions to achieve a high efficiency 90 micron Raman conversion in ammonia, with both short and long pulses.      99. 1,2,3-Triazolodiazepines. I. Preparation and benzodiazepine receptor binding of 1-benzyl- and 1-phenethyl-1,2,3-triazolo-[4,5-b][1,4]diazepines      Giuliana Biagi  Irene Giorgi  Oreste Livi  Valerio Scartoni  Silvia Velo  Antonio Lucacchini  Generoso Senatore  Pier Luigi Barili 《Journal of heterocyclic chemistry》1995,32(1):169-176 Several new 1,2,3-triazolo[4,5-b][1,4]diazepines were prepared starting from 1-benzyl-1 and 1-phenethyl-4,5-diamino-1,2,3-triazole 2 (Scheme 1), by condensation reactions with β-diketones (Scheme 2), β-ketoesters (Scheme 3), and diethyl malonates (Scheme 4). In the first case we obtained compounds 3 and 4 with basic properties, while the ester function condensations gave cyclic amide derivatives 7, 8, 10, 12 and 13 with acid properties. Some N-methyl derivatives 11, 14 and 15 were obtained from the cyclic amide compounds. Most of compounds were tested for their ability to displace [3H]flunitrazepam from bovine brain membranes but no compound showed benzodiazepine receptor binding affinity.      100. Triazolylbenzimidazolthiones and derivatives of the new 1,2,3‐triazolo[ 1,5‐a][ 1,3,5]benzotriazepine heterocycle      Giuliana Biagi  Irene Giorgi  Oreste Livi  Antonio Nardi  Valerio Scartoni 《Journal of heterocyclic chemistry》2002,39(6):1293-1298 Four new triazolylbenzimidazolthione derivatives (2a‐d), analogous to triazolylbenzimidazolone derivatives previously tested as activators of the BKCa potassium channels, were prepared and assayed without success. Some derivatives of a new tricyclic nitrogen heterocycle, 1,2,3‐triazolo[1,5‐a][1,3,5]benzo‐triazepine, bearing a carboxamido group in the 3 position, other substituents in the 8 position and a carbonyl (5a‐d) or thione (6a‐c) or methylthio (7a‐c) function in the 5 position were synthesised. The nucleophilic displacement of the methylthio substituent with morpholine or cyclopentylamine provided the 5‐amino‐substituted tricyclic derivatives 8a‐d. Starting from the l‐(2‐nitrophenyl)‐4‐cyano‐5‐amino‐1,2,3‐triazole (9), the 3‐cyano‐triazolobenzotriazepin‐5‐one derivative 12 was also obtained. The majority of the new compounds were tested towards the BKCa potassium channels, the benzodiazepine and adenosine A1 and A2a receptors, but no remarkable activity was detected.      [首页] « 上一页 [5] [6] [7] [8] [9] 10 [11] [12] [13] [14] [15] 下一页 » 末  页»

Controlled dumping of pulses of laser radiation ranging from MIR to the MM by means of optical semiconductor switching

A simple method to produce sub-ns pulses of laser radiation with wavelength ranging from middle infrared (MIR) to millimeter (MM) is experimentally demonstrated. The system operates with a single OSS (optical semiconductor switching) driven by a ns Nd laser. Pulse control is produced by varying the distance of a mirror from an OSS used as a cavity dumping. The effectiveness of this sub-ns MM pulse generation is larger than the one observed in other schemes. Pulses with 500-ps FWHM and 15-W power were produced at 2.65 mm with a time compression compared to the 2-ns FWHM of the 1.06-μm driving laser. Received: 30 October 2000 / Revised version: 26 January 2001 / Published online: 9 May 2001     

Bounds and monotonicity for the generalized Robin problem

We consider the principal eigenvalue λ ₁^Ω(α) corresponding to Δu = λ (α) u in on ∂Ω, with α a fixed real, and a C ^0,1 bounded domain. If α > 0 and small, we derive bounds for λ ₁^Ω(α) in terms of a Stekloff-type eigenvalue; while for α > 0 large we study the behavior of its growth in terms of maximum curvature. We analyze how domain monotonicity of the principal eigenvalue depends on the geometry of the domain, and prove that domains which exhibit domain monotonicity for every α are calibrable. We conjecture that a domain has the domain monotonicity property for some α if and only if it is calibrable. Robert Smits: This author was partially supported by a grant of the National Security Agency, grant #H98230-05-1-0060.     

Parametric study of a ramanp-H2 laser with over 30 MW emission at 16 μm

Summary In this work the main parameters which define the threshold, the temporal shape and the stability ofp-H₂ Raman laser have been investigated. Our results show a very high-power conversion efficiency (130%) and for each pump CO₂ line we can dispose of a correspondent line (pulse≥1J/50 ns) in the 16 μm range. This is foundamental as far as UF₆ isotopic separation is concerned.

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Riassunto In questo lavoro sono stati studiati i principali parametri che definiscono la soglia, la forma temporale e la stabilità di un laser Raman a para-idrogeno (16 μm). I nostri risultati mostrano un'alta efficienza di conversione di potenza (130%) per ciascuna riga del laser a CO₂ permettendo una buona tunabilità nel range dei 16 μm. Questo è fondamentale per la separazione isotopica di UF₆.

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Резюме В этой работе исследуются основные параметры, которые определяют порог, временную форму и стабильностьp-H₂ рамановского лазера. Наши результаты показывают очень высокую эффективность конверсии (130%). Для каждой линии CO₂ накачки мы можем сопоставить соответствующую линию (импульс≥1 Дж/50 нс) в диапазоне 16 мкм. Это является основой для разделения изотопов UF₆.

     

High efficiency long pulse FIR Raman conversion in ammonia

Generally the quantum efficiency of FIR Raman generation in molecular gases is below the theoretical value. This disagreement is particularly evident in Raman scattering from pulsed sources with short pulse length, when the vibrational saturation limits the power conversion. Other nonlinear processes can overcome this saturation, but they require a very intense pump power for too short a time to use the FIR radiation in high sensitive experiments with heterodyne detection. This is the case, for instance, of RFWM. In this work we describe the experimental conditions to achieve a high efficiency 90 micron Raman conversion in ammonia, with both short and long pulses.     

1,2,3-Triazolodiazepines. I. Preparation and benzodiazepine receptor binding of 1-benzyl- and 1-phenethyl-1,2,3-triazolo-[4,5-b][1,4]diazepines

Several new 1,2,3-triazolo[4,5-b][1,4]diazepines were prepared starting from 1-benzyl-1 and 1-phenethyl-4,5-diamino-1,2,3-triazole 2 (Scheme 1), by condensation reactions with β-diketones (Scheme 2), β-ketoesters (Scheme 3), and diethyl malonates (Scheme 4). In the first case we obtained compounds 3 and 4 with basic properties, while the ester function condensations gave cyclic amide derivatives 7, 8, 10, 12 and 13 with acid properties. Some N-methyl derivatives 11, 14 and 15 were obtained from the cyclic amide compounds. Most of compounds were tested for their ability to displace [³H]flunitrazepam from bovine brain membranes but no compound showed benzodiazepine receptor binding affinity.     

Triazolylbenzimidazolthiones and derivatives of the new 1,2,3‐triazolo[ 1,5‐a][ 1,3,5]benzotriazepine heterocycle

Four new triazolylbenzimidazolthione derivatives (2a‐d), analogous to triazolylbenzimidazolone derivatives previously tested as activators of the BK_Ca potassium channels, were prepared and assayed without success. Some derivatives of a new tricyclic nitrogen heterocycle, 1,2,3‐triazolo[1,5‐a][1,3,5]benzo‐triazepine, bearing a carboxamido group in the 3 position, other substituents in the 8 position and a carbonyl (5a‐d) or thione (6a‐c) or methylthio (7a‐c) function in the 5 position were synthesised. The nucleophilic displacement of the methylthio substituent with morpholine or cyclopentylamine provided the 5‐amino‐substituted tricyclic derivatives 8a‐d. Starting from the l‐(2‐nitrophenyl)‐4‐cyano‐5‐amino‐1,2,3‐triazole (9), the 3‐cyano‐triazolobenzotriazepin‐5‐one derivative 12 was also obtained. The majority of the new compounds were tested towards the BK_Ca potassium channels, the benzodiazepine and adenosine A₁ and A_2a receptors, but no remarkable activity was detected.