University of Mons

About: University of Mons is a education organization based out in Mons, Belgium. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 3073 authors who have published 9465 publications receiving 294776 citations.

Measurement of jet fragmentation into charged particles in pp and PbPb collisions at √sNN=2.76 TeV

Abstract: Jet fragmentation in pp and PbPb collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair was studied using data collected with the CMS detector at the LHC. Fragmentation functions are constructed using charged-particle tracks with transverse momenta pt > 4 GeV for dijet events with a leading jet of pt > 100 GeV. The fragmentation functions in PbPb events are compared to those in pp data as a function of collision centrality, as well as dijet-pt imbalance. Special emphasis is placed on the most central PbPb events including dijets with unbalanced momentum, indicative of energy loss of the hard scattered parent partons. The fragmentation patterns for both the leading and subleading jets in PbPb collisions agree with those seen in pp data at 2.76 TeV. The results provide evidence that, despite the large parton energy loss observed in PbPb collisions, the high-pt component of the fragmentation function evaluated with respect to the reconstructed jet momentum is not strongly modified in comparison to jet fragmentation in vacuum.

Polylactide (PLA) designed with desired end‐use properties: 1. PLA compositions with low molecular weight ester‐like plasticizers and related performances

Abstract: Polylactide (PLA) is an attractive candidate for replacing petrochemical polymers because it is biodegradable and produced from annually renewable resources. Characterized by high tensile strength, unfortunately the brittleness and rigidity of PLA limit its applicability. For a great number of applications such as packaging,fibers,films, etc., it is of high interest to formulate new grades with improved flexibility and better impact properties. In this objective, a specific PLA grade (L/D isomer ratio of 96:4, high molecular weight) was melt-mixed with selected plasticizers: bis(2-ethylhexyl) adipate (DOA), glyceryl triacetate (GTA), and tributyl O-acetylcitrate (TBAC). Their effect on the molecular, thermal, and mechanical properties of PLA was investigated for content up to 20wt% plasticizer and the results were correlated with a particular attention to the relationship between property and application. Using the solubility and interaction parameters, a tentative evaluation of the product that could act as the most effective plasticizer for PLA has been performed and the obtained results have been corroborated with the materials physical properties. Excellent mechanical performances were obtained using the plasticizer having the lowest molecular mass (GTA) and the best interaction parameter. In relation to plasticizer amount/nature, the glass transition temperature of PLA (62-C) is decreased by plasticizing by more than 30-C, whereas better impact properties and lower stiffness are measured. The optimal formulations targeted to the final applications are clearly characterized by specific end-use properties: improved crystallization rates (PLA-DOA); high elongation at break and tensile strength (PLA-GTA, PLA-TBAC), medium to high impact properties (PLA-DOA, PLA-GTA) compositions. Copyright # 2008 John Wiley & Sons, Ltd.

Magnetic iron oxide nanoparticles for biomedical applications.

Abstract: Due to their high magnetization, superparamagnetic iron oxide nanoparticles induce an important decrease in the transverse relaxation of water protons and are, therefore, very efficient negative MRI contrast agents. The knowledge and control of the chemical and physical characteristics of nanoparticles are of great importance. The choice of the synthesis method (microemulsions, sol-gel synthesis, laser pyrolysis, sonochemical synthesis or coprecipitation) determines the magnetic nanoparticle's size and shape, as well as its size distribution and surface chemistry. Nanoparticles can be used for numerous in vivo applications, such as MRI contrast enhancement and hyperthermia drug delivery. New developments focus on targeting through molecular imaging and cell tracking.

Probe-based 3-D nanolithography using self-amplified depolymerization polymers.

Abstract: Scanning probes are capable of addressing and modifying surface structures on the atomic scale, [ 1 ] a capability that has been exploited to create molecular logic devices. [ 2 ] However, in realworld applications, the production of nanoscale patterns and devices requires substantial throughput capabilities in combination with suffi cient tip endurance to address areas on the order of 0.1–1 mm 2 at high resolution. At a typical pixel pitch of 10 nm, this translates to 10 8 –10 10 pixels being written with a single tip. Therefore a highly sensitive patterning approach that is gentle on the tip would be indispensable. Besides the well-established method of local anodic oxidation, [ 3 – 5 ] recent developments in this direction are the fi eld-induced deposition of materials [ 6 , 7 ] and the tip-induced modifi cation or removal of thermomechanically responsive organic materials. [ 8 – 12 ] In addition, it has been shown that on polymeric substrates the wear on a sliding silicon tip can be virtually eliminated, [ 13 ] which is a prerequisite for high-resolution patterning on technologically viable scales. Other stimuli have been used to structure polymers locally using atomic force microscopy (AFM) tips, e.g., mechanical forces in plowing [ 14 ] and ultrasonic patterning [ 15 ] or electron irradiation using fi eld emission from the tip. [ 16 ] In this paper, we describe the fabrication of twoand threedimensional structures based on the local removal of a resist polymer using heated tips. Previous experiments have shown that suffi cient energy is provided by heated tips to break the chemical bonds of a Diels–Alder material, [ 11 ] which subsequently decomposes into volatile monomer units. However, the overall patterning effi ciency is low. The effi ciency can be dramatically enhanced by using self-amplifi ed depolymerization (SAD) polymers. Here, the breaking of a single bond induces the spontaneous depolymerization of the entire polymer chain, [ 17 , 18 ] a concept that was fi rst demonstrated in the early 80’s as a dry lithography approach. Recently it was discovered that using phthalaldehyde SAD polymers two-dimensional