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See detailElectronic and structural transitions in dense liquid sodium
Raty, Jean-Yves ULg; Schwegler, E.; Bonev, S. A.

in Nature (2007), 449(7161), 448-451451

At ambient conditions, the light alkali metals are free-electron-like crystals with a highly symmetric structure. However, they were found recently to exhibit unexpected complexity under pressure 1-6. It ... [more ▼]

At ambient conditions, the light alkali metals are free-electron-like crystals with a highly symmetric structure. However, they were found recently to exhibit unexpected complexity under pressure 1-6. It was predicted from theory 1.2 - and later confirmed by experiment 3-5 - that lithium and sodium undergo a sequence of symmetry-breaking transitions, driven by a Peierls mechanism, at high pressures. Measurements of the sodium melting curve 6 have subsequently revealed an unprecedented (and still unexplained) pressure-induced drop in melting temperature from 1,000 K at 30 GPa down to room temperature at 120 GPa. Here we report results from ab initio calculations that explain the unusual melting behaviour in dense sodium. We show that molten sodium undergoes a series of pressure-induced structural and electronic transitions, analogous to those observed in solid sodium but commencing at much lower pressure in the presence of liquid disorder. As pressure is increased, liquid sodium initially evolves by assuming a more compact local structure. However, a transition to a lower-coordinated liquid takes place at a pressure of around 65 GPa, accompanied by a threefold drop in electrical conductivity. This transition is driven by the opening of a pseudogap, at the Fermi level, in the electronic density of states - an effect that has not hitherto been observed in a liquid metal. The lower-coordinated liquid emerges at high temperatures and above the stability region of a close-packed free-electron-like metal. We predict that similar exotic behaviour is possible in other materials as well. [less ▲]

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See detailGlobal overview of the educational system in the French speaking Community of Belgium
Schillings, Patricia ULg; Gabelica, C.

E-print/Working paper (2007)

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See detailBibliotheca Lipsiana Bruxellensis : les livres de Juste Lipse conservés à la Bibliothèque royale de Belgique : exposition "Constance et inconstance" organisée au Musée de la Maison d'Erasme du 1er décembre 2006 au 4 février 2007
Adam, Renaud ULg; De Schepper, Marcus

Book published by Brepols (2007)

Ce volume comporte deux parties : un catalogue et un inventaire publiés à l’occasion de l'exposition organisée par la Bibliothèque royale de Belgique au Musée de la Maison d’Érasme. Dans le catalogue, on ... [more ▼]

Ce volume comporte deux parties : un catalogue et un inventaire publiés à l’occasion de l'exposition organisée par la Bibliothèque royale de Belgique au Musée de la Maison d’Érasme. Dans le catalogue, on trouvera notamment le texte des cinq lettres de Juste Lipse à son disciple Puteanus découvertes récemment. L'inventaire présente les pièces relatives à Juste Lipse conservées à la Bibliothèque royale (manuscrits, livres imprimés, etc.). De copieux index facilitent la consultation de cet ouvrage de référence qui décrit une des plus fameuses collections concernant le grand humaniste européen Juste Lipse. [less ▲]

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See detailUne lettre inconnue de Max Rooses au chanoine Nicolas Henrotte
Adam, Renaud ULg

in De Gulden Passer = Le compas d'or (2007), 85

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See detailIntérêts et voies d'abord de la stadification paraaortique laparoscopique dans les cancers avances du col utérin
Kridelka, Frédéric ULg; Goffin, Frédéric ULg

in Revue Médicale de Liège (2007), 62 Spec No 2

The stage of a cervical neoplasm is defined on clinical criteria as reported by the International Federation of Gynecology and Obstetrics. Treatment planning however is based on this clinical stage, but ... [more ▼]

The stage of a cervical neoplasm is defined on clinical criteria as reported by the International Federation of Gynecology and Obstetrics. Treatment planning however is based on this clinical stage, but moreover on histological variables obtained at surgical staging. Regarding advanced stage cervical cancer, the recommanded treatment consists in a radical radiotherapy together with concomitant chemotherapy. The target volume of the radiation treatment is directly dependent on the paraaortic lymph node status, the radiological evaluation of which remains unsatisfactory due to lack of sensitivity. We report our experience with two laparoscopic approaches (transperitoneal and retroperitoneal) allowing a histological paraaortic nodal status to be obtained prior to initiating the definitive treatment. [less ▲]

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See detailInverse modelling of nanoindentation tests to identify Ti-555 behaviour
Gerday, Anne-Françoise ULg; Clement, N.; Jacques, P. J. et al

in Proceedings of the 11th world conference on titanium (2007)

Nanoindentation is commonly used to probe local plastic properties of materials [1-4]. From these nanoindentation tests, finite element (FE) modeling is currently used to identify material data. The ... [more ▼]

Nanoindentation is commonly used to probe local plastic properties of materials [1-4]. From these nanoindentation tests, finite element (FE) modeling is currently used to identify material data. The general ambition of this research is to extract the material parameters representative of the response of a new generation of Ti alloy, called Ti-555, in order to perform simulations on representative microscopic cells and guide the optimization of the alloy. In this paper, the identification of the flow parameters of the -phase of this alloy, using a microscopic crystal plasticity-based constitutive law is described. The nanoindentation tests are performed using a pyramidal Berkovich diamond indenter and the different slip systems of the b.c.c. -phase are supposed to be activated with identical critical shear stresses. The FE nanoindentation force-displacement curves obtained with the microscopic constitutive law are compared to the experimental ones. The influence of the orientation of the grains is also analysed. A previous sensivity analysis on different parameters with different constitutive laws and materials has shown a great influence of different parameters on the nanoindentation results but almost no influence of other parameters [5-6]. [less ▲]

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See detailSleep disorders and suicidal ideation in patients with depressive disorder.
Chellappa, Sarah Laxhmi ULg; Araujo, John Fontenele

in Psychiatry Research (2007), 153(2), 131-6

An intrinsic association between suicidal ideation and sleep disorders in patients with depressive disorder has been observed in recent studies. This study was conducted in order to examine the ... [more ▼]

An intrinsic association between suicidal ideation and sleep disorders in patients with depressive disorder has been observed in recent studies. This study was conducted in order to examine the relationship between suicidal ideation and sleep disorders, such as insomnia and excessive sleepiness, in outpatients with major depressive disorder. Seventy patients with diagnoses of major depressive disorder were interviewed and assessed with the Sleep Habits Questionnaire and the Beck Scale for Suicidal Ideation (SSI). Data analyses were performed through descriptive analysis, Students t-test, Chi-square test and logistic regression model, with a statistical significance of 5%. In this study, depressed patients had high SSI scores (6.12+/-2.67), particularly for active suicidal ideation (1.61+/-0.39) and specific plans for suicide components (1.51+/-0.40). Depressed patients with insomnia had significantly higher SSI scores (7.39+/-2.84), in relation to patients with excessive sleepiness (3.68+/-1.73). Furthermore it was observed that insomniac patients had significantly higher scores on the following components: active suicide ideation, specific plans for suicide and previous suicide attempts. The results of multivariate analysis showed that only insomnia had a significant association with suicidal ideation. Thus, sleep disturbances, particularly insomnia, should be considered in the assessment of suicidal risk in outpatients with depressive disorder. [less ▲]

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See detailL'"étranger" au pays de sumer à l'époque de la troisième dynastie d'Ur
Colonna d'Istria, Laurent ULg; Louis, Philippe

in Riaud, Jean (Ed.) L'étranger dans la Bible et ses lectures (2007)

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See detailDevonian-Carboniferous Boundary global correlations and their paleogeographic implications for the assembly of pangaea.
Streel, Maurice ULg; Marshall, J.E.A.

in Royal Netherlands Academy of Arts and Sciences (2007)

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See detailAn activity-based approach for surveying and modelling travel behaviour: analysis of the mixed-mode design effects
Cools, Mario ULg; Moons, Elke; Wets, Geert

Conference (2007)

Reports from various international organisations, like for instance the European Commission’s White paper “European transport policy for 2010: time to decide” show that policy makers acknowledge the ... [more ▼]

Reports from various international organisations, like for instance the European Commission’s White paper “European transport policy for 2010: time to decide” show that policy makers acknowledge the increasing importance of mobility. Mobility is not just considered to be a cornerstone for economic growth, but also seen as a social need that offers people the opportunity for self-fulfilment and relaxation. In order to lead an efficient policy, governments require reliable predictions of travel behaviour, traffic performance, and traffic safety. Thus, traffic and transportation models can provide the right framework to support long-term decisions. On an international level, activity-based models have become one of the leading paradigms to model travel behaviour. The most important characteristic of these models is that travel is considered as a derivative from the activities that individuals and households need or wish to perform. This means that travel is no longer seen as an isolated fact in these models, which is a great advantage in comparison to the classic models. The development of activity-based models requires very specific data. Since a special emphasis was laid on the dynamic character of the model, both the planned and executed activities were surveyed. 2500 households were selected using a stratified cluster technique. The selected household were asked to fill out an activity-diary and to report rescheduling decisions during a one-week period. Approximately one half of the households received a PDA-module; the other half was surveyed by means of a traditional paper-and-pencil diary. Although both data collection modes were designed in such way that the correspondence of the questions was optimised, it remains essential to identify differences in the data that are introduced by using multiple modes. This paper starts with describing the differences that existed in the questionnaire design of the two modes, and then further explores the statistical differences in terms of some key observations, such as average number of trips reported, and average travel time. [less ▲]

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See detailPalynomorph distribution and bathymetry in the Chanxhe section (eastern Belgium), reference for the neritic late to latest Famennian transition (Late Devonian).
Maziane-Serraj, N; Hartkopf-Fröder, C; Streel, Maurice ULg et al

in Geologica Belgica (2007), 10(3-4), 170-175

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See detailStudy on Real-time Evaluation of Slagging Propensities of Coals Based on Laser-induced Breakdown Spectroscopy
Xie, Chengli; Lu, Jidong; Li, Jie ULg et al

in Proceedings of the CSEE (2007), 27(23), 24-27

A method of real-time evaluation of slagging propensities of coals based on element quantitative technique by laser-induced breakdown spectroscopy Was introduced .An experiment apparatus Was set up ... [more ▼]

A method of real-time evaluation of slagging propensities of coals based on element quantitative technique by laser-induced breakdown spectroscopy Was introduced .An experiment apparatus Was set up according to the principle of analysis technique,an d in which six typical coals samples were analyzed.Four ones were used to construct calibration curves of the analyzed elements as a reference diagram determining the relation between element concentration an d spectral intensity, afterwards,analyzed silicon element an d aluminum element in other sampleswere surveyed with the reference diagram .Ratios of silicon dioxide to aluminum trioxide were computed subsequently according to chemical calculation to evaluate the slagging propensities of coals.Comparing the evaluation with the computed result based on ash composition analyzed with conventional measure,the two match well.After all,some improvement program s to optimize the measurement mechanism were discussed. [less ▲]

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See detailInvestigation on Laser-induced Breakdown Spectroscopy of Potassium Chloride Solution
Zhang, Wenyan; Lin, Zhaoxiang; Lu, Jidong et al

in Applied Laser (2007), 27(2), 121-123

The experimental setup for laser—induced breakdown spectroscopy test was designed with pulsed Nd:YAG laser,spectrograph and ICCD and so on.Furthermore the potassium chloride solution spectra signals were ... [more ▼]

The experimental setup for laser—induced breakdown spectroscopy test was designed with pulsed Nd:YAG laser,spectrograph and ICCD and so on.Furthermore the potassium chloride solution spectra signals were detected by this setup.The spectra lines of the trace elements such as natrium (20mg/1),magnesium(1 mg/1),calcium(3 mg/1)are recorded.Experiment results show that delay time is one of the important parameters when qualitative analysis.It is easy for LIBS technology to detect multi—elements simultaneity if delay time is appropriate,and qualitative analysis has demonstrated that the feasibility of detecting trace poisonous metals in waste water using LIBS、 [less ▲]

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See detailStudy on the Property of Laser-induced Plasma of Pulverized Coal
Xie, Chengli; Lu, Jidong; Li, Jie ULg et al

in Journal of Engineering Thermophysics (2007), 28(s2), 133-136

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