Gradation of Algebras of Curves by the Winding Number

We construct a new grading on the Goldman Lie algebra of a closed oriented surface by the winding number. This grading induces a grading on the HOMFLY-PT skein algebra and related algebras. Our work supports the conjectures of B. Cooper and P. SamuelsonComment: Changed acknowledgments and Definition 2.

Hardware-Supported Cryptographic Protection of Random Access Memory

Confidential Computing is the protection of data in use from access or modification by any unauthorized agent, including privileged software. For example, in Intel SGX (Client and Scalable versions) and TDX, AMD SEV, Arm CCA, and IBM Ultravisor this protection is implemented via access control policies. Some of these architectures also include memory protection schemes relying on cryptography, to protect against physical attacks. We review and classify such schemes, from academia and industry, according to protection levels corresponding of adversaries with varying capabilities, budget, and strategy. The building blocks of all memory protection schemes are encryption and integrity primitives and modes of operation, as well as anti-replay structures. We review these building blocks, consider their possible combinations, and evaluate the performance impact of the resulting schemes. We present a framework for performance evaluation in a simulated system. To understand the best and worst case overhead, systems with varying load levels are considered. We propose new solutions to further reduce the performance and memory overheads of such technologies. Advanced counter compression techniques make it viable to store counters used for replay protection in a physically protected memory. By additionally repurposing some ECC bits to store integrity tags, we can provide the highest levels of confidentiality, integrity, and replay protection at a hitherto unattained performance penalty, namely 3.32%, even under extreme load and at costs that make them reasonable in data centers. Combinations of technologies that are suitable for client devices are also discussed

Cristallochimie de polymères de coordination de type carboxylate d’uranyle et carboxylate mixte uranyle - lanthanide

Ce travail de thèse décrit la synthèse, l’étude cristallochimique et le comportement thermique de polymères de coordination à base de cations uranyle, ou mixtes uranyle-lanthanide complexés par des ligands carboxylates aromatiques (acide phthalique et dérivés). L’emploi de 7 molécules polycarboxylates a conduit à la formation de plus de 25 nouveaux composés type Uranyl-Organic Framework (UOF) ou hybrides uranyle-organique, ou encore mixtes uranyle-lanthanide-organique. Certains de ces ligands on montré une grande diversité d’arrangements atomiques, avec par exemple, l’isophthalate qui conduit à la formation de 10 complexes de coordination, alors que d’autres (par exemple terephthalate) ont permis d’isoler un seul type d’assemblage. Certaines de ces phases contiennent classiquement des briques de construction inorganiques monomériques ou tétramériques alors que d’autres mettent en évidence des blocs trimériques linéaires ou octamériques originals, ou encore des systèmes de chaînes inorganiques générant des structures à tunnels inédits. Une configuration rare d’interaction cation-cation (CCI ou U=O-U) a été également identifiée dans l’isophthalate à base d’unité octamérique. La synthèse de toutes ces phases a permis une meilleure compréhension des réactions hydrothermales et de l’influence de différents paramètres influant la formation du produit final. Pour les phases obtenues sous formes pures, les comportements thermiques et leur stabilité ont été étudiés. Ces expériences ont permis d’établir des relations entre le précurseur initial, la dégradation thermique et les conditions de formation de l’oxyde final. Les spectres de fluorescence ont été collectés et indiquent des informations sur l’influence de la nature du ligand organique ou du type du motif de construction inorganique.This thesis work concerns the synthesis, crystal structural study and thermal behavior of coordination polymers type uranyl and mixed uranyl-lanthanide aromatic carboxylates. Using a series of 7 aromatic carboxylate ligands, more than 25 new uranyl (so-called Uranyl-Organic Framework or UOF) and mixed uranyl-lanthanide coordination polymers have been synthesized and described in this manuscript. Some of the ligands have proven to be very prolific such as the isophthalic acid, which is present in 10 coordination polymers and with others (such as terephthalic acid) only one complex could be isolated. Some of the obtained phases contain typical monomeric or tetrameric SBUs and others possess unique features such as octanuclear SBU with an edge sharing CCI (U=O-U), linear trinuclear SBU or polymeric SBU delimiting large tunnel systems. The synthesis of all these phases conducted to a better understanding of the hydrothermal reactions and the influence of different parameters over the final reaction product. For each of the phases obtained pure the thermal behavior and thermal stability have been studied. These experiments offer a better understanding of the relation between the structure of the initial complex, the thermal degradation conditions and the nature of final oxide. Also for these phases the fluorescence emission spectra were recorded, offering information about the influence of different ligands or different type of SBUs over the typical uranyl spectrum

Cristallochimie de polymères de coordination de type carboxylate d uranyle et carboxylate mixte uranyle - lanthanide

Ce travail de thèse décrit la synthèse, l étude cristallochimique et le comportement thermique de polymères de coordination à base de cations uranyle, ou mixtes uranyle-lanthanide complexés par des ligands carboxylates aromatiques (acide phthalique et dérivés). L emploi de 7 molécules polycarboxylates a conduit à la formation de plus de 25 nouveaux composés type Uranyl-Organic Framework (UOF) ou hybrides uranyle-organique, ou encore mixtes uranyle-lanthanide-organique. Certains de ces ligands on montré une grande diversité d arrangements atomiques, avec par exemple, l isophthalate qui conduit à la formation de 10 complexes de coordination, alors que d autres (par exemple terephthalate) ont permis d isoler un seul type d assemblage. Certaines de ces phases contiennent classiquement des briques de construction inorganiques monomériques ou tétramériques alors que d autres mettent en évidence des blocs trimériques linéaires ou octamériques originals, ou encore des systèmes de chaînes inorganiques générant des structures à tunnels inédits. Une configuration rare d interaction cation-cation (CCI ou U=O-U) a été également identifiée dans l isophthalate à base d unité octamérique. La synthèse de toutes ces phases a permis une meilleure compréhension des réactions hydrothermales et de l influence de différents paramètres influant la formation du produit final. Pour les phases obtenues sous formes pures, les comportements thermiques et leur stabilité ont été étudiés. Ces expériences ont permis d établir des relations entre le précurseur initial, la dégradation thermique et les conditions de formation de l oxyde final. Les spectres de fluorescence ont été collectés et indiquent des informations sur l influence de la nature du ligand organique ou du type du motif de construction inorganique.This thesis work concerns the synthesis, crystal structural study and thermal behavior of coordination polymers type uranyl and mixed uranyl-lanthanide aromatic carboxylates. Using a series of 7 aromatic carboxylate ligands, more than 25 new uranyl (so-called Uranyl-Organic Framework or UOF) and mixed uranyl-lanthanide coordination polymers have been synthesized and described in this manuscript. Some of the ligands have proven to be very prolific such as the isophthalic acid, which is present in 10 coordination polymers and with others (such as terephthalic acid) only one complex could be isolated. Some of the obtained phases contain typical monomeric or tetrameric SBUs and others possess unique features such as octanuclear SBU with an edge sharing CCI (U=O-U), linear trinuclear SBU or polymeric SBU delimiting large tunnel systems. The synthesis of all these phases conducted to a better understanding of the hydrothermal reactions and the influence of different parameters over the final reaction product. For each of the phases obtained pure the thermal behavior and thermal stability have been studied. These experiments offer a better understanding of the relation between the structure of the initial complex, the thermal degradation conditions and the nature of final oxide. Also for these phases the fluorescence emission spectra were recorded, offering information about the influence of different ligands or different type of SBUs over the typical uranyl spectrum.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

Crystal Chemistry of Uranyl Carboxylate Coordination Networks Obtained in the Presence of Organic Amine Molecules

International audienc

The crystal chemistry of uranium carboxylates

International audienc

Room temperature crystallization of trichlorodioxouranate [UO2Cl3(L)] species in molecular assemblies involving aliphatic dicarboxylate linkers

International audienc

Isobar separation of 32Si from 32S in AMS using a passive absorber

An accelerator mass spectrometry (AMS) method has been developed to detect 32Si and separate it from its intense isobar 32S. This separation is achieved using a passive absorber cell in front of a gas ionization chamber at an energy of 30 MeV at the 6 MV Tandem accelerator at the Laboratory of Ion Beam Physics (LIP) at the ETH Zurich. Thereby, the background originating from light recoils was identified and minimized. Additionally, the deviation of the position of the observed spectrum from the expected was explained. The new method is currently undergoing characterisations aiming for the half-life measurement of 32Si.ISSN:0168-583XISSN:1872-958

Uranyl–Pyromellitate Coordination Polymers: Toward Three-Dimensional Open Frameworks with Large Channel Systems

Five coordination polymers based on uranyl–pyromellitates have been hydrothermally synthesized, and their single-crystal XRD structures have been analyzed. These different compounds, obtained with different ammonia concentrations, exhibit either three-dimensional (3D) or two-dimensional (2D) networks. Complex <b>1</b>, (UO₂)₂(H₂O)₂(btec)·H₂O, is a quite compact 3D structure containing isolated 7-fold coordinated uranyl cations linked through the pyromellitate (noted btec) and encapsulating free water species. Phase (NH₄)­[(UO₂)₂(OH)­(H₂O)­(btec)]·1.75H₂O (<b>2</b>) offers a second 3D architecture built up from dinuclear 7-fold coordinated uranyl units and mononuclear 8-fold coordinated uranyl units linked through the organic ligands. This framework is slightly more open because narrow one-dimensional (1D) channels trapping water species are visible. Phase <b>3</b>, (NH₄)₂[(UO₂)₆O₂(OH)₄(btec)_1.5]·11H₂O, consists of large 1D lozenge-shaped channels (8.2 Å × 8.6 Å) delimited by infinite ribbons (composed of 7-fold coordinated uranyl polyhedra sharing edges) and pyromellitate ligands. Ammonium cations as well as water molecules are trapped within the channels. The fourth compound, (NH₄)₆[(UO₂)₃(btec)₃]·12H₂O (<b>4</b>), is lamellar with sheets containing 8-fold coordinated uranyl centers linked through the btec molecules, which have two nonbonded carboxylate functions interacting with the intercalated ammonium cations. Compound <b>5</b> also consists of a layered structure, (UO₂)₃(OH)₂(H₂O)₂(btec), with uncommon trinuclear building blocks containing 7-fold (×2) and 8-fold (×1) coordinated uranyl centers, linked through the btec molecules. Fluorescence spectra of compounds <b>1</b>, <b>3</b>, and <b>4</b> are also measured

Series of Mixed Uranyl–Lanthanide (Ce, Nd) Organic Coordination Polymers with Aromatic Polycarboxylates Linkers

Three series of mixed uranyl-lanthanide (Ce or Nd) carboxylate coordination polymers have been successfully synthesized by means of a hydrothermal route using either conventional or microwave heating methods. These compounds have been prepared from mixtures of uranyl nitrate, lanthanide nitrate together with phthalic acid (<b>1</b>,<b>2</b>), pyromellitic acid (<b>3</b>,<b>4</b>), or mellitic acid (<b>5</b>,<b>6</b>) in aqueous solution. The X-ray diffraction (XRD) single-crystal revealed that the phthalate complex (UO₂)₄O₂Ln­(H₂O)₇(1,2-bdc)₄·NH₄·<i>x</i>H₂O (Ln = Ce­(<b>1</b>), Nd­(<b>2</b>); <i>x</i> = 1 for <b>1</b>, <i>x</i> = 0 for <b>2</b>), is based on the connection of tetranuclear uranyl-centered building blocks linked to discrete monomeric units LnO₂(H₂O)₇ via the organic species to generate infinite chains, intercalated by free ammonium cations. The pyromellitate phase (UO₂)₃Ln₂(H₂O)₁₂(btec)₃·5H₂O (Ce­(<b>3</b>), Nd­(<b>4</b>)) contains layers of monomeric uranyl-centered hexagonal and pentagonal bipyramids linked via the carboxylate arms of the organic molecules. The three-dimensionality of the structure is ensured by the connection of remaining free carboxylate groups with isolated monomeric units LnO₂(H₂O)₇. The network of the third series (UO₂)₂(OH)­Ln­(H₂O)₇(mel)·5H₂O (Ce­(<b>5</b>), Nd­(<b>6</b>)) is built up from dinuclear uranyl units forming layers through connection with the mellitate ligands, which are further linked to each other through discrete monomers LnO₃(H₂O)₆. The thermal decomposition of the various coordination complexes led to the formation of mixed uranium-lanthanide oxide, with the fluorite-type structure at 1500 °C (for <b>1</b>, <b>2</b>) or 1400 °C for <b>3</b>–<b>6</b>. Expected U/Ln ratio from the crystal structures were observed for compounds <b>1</b>–<b>6</b>