Publications by Camelia Borca | EPFL Graph Search

Additives: Their Influence on the Humidity- and Pressure-Induced Crystallization of Amorphous CaCO3

Camelia Borca, Alan Böhlen, Huachuan Du, Esther Amstad, Mathias Steinacher, Clémence Courrégelongue

Nature possesses a unique control over the formation of CaCO3 crystals that imparts fascinating mechanical properties to many CaCO3-based biomaterials. This high level of control is, at least in part, achieved through the use of certain soluble additives t ...

AMER CHEMICAL SOC2020

Tuning the Incorporation of Magnesium into Calcite during Its Crystallization from Additive-Free Aqueous Solution

Camelia Borca, Huachuan Du, Esther Amstad

Under ambient conditions, marine organisms are able to synthesize a variety of functional materials, ranging from eye lenses to protective shells through the meticulous control over magnesium incorporation into calcite during its crystallization. The mecha ...

AMER CHEMICAL SOC2019

Amorphous CaCO3: Influence of the Formation Time on Its Degree of Hydration and Stability

Camelia Borca, Francesco Stellacci, Huachuan Du, Esther Amstad, Anna Murello, Mathias Steinacher

Calcium carbonate (CaCO3) is one of the most abundant biominerals that is prevalent in rocks and often used as a structural material in marine animals. Many of these natural CaCO3-based materials display excellent mechanical properties that are difficult t ...

2018

Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO2

Majed Chergui, Paul Beaud, Camelia Borca, Jochen Rittmann, Mahsa Silatani, Edoardo Baldini, Fabio Giacomo Santomauro, Patric Zimmermann

Transition metal oxides are among the most promising solar materials, whose properties rely on the generation, transport and trapping of charge carriers (electrons and holes). Identifying the latter's dynamics at room temperature requires tools that combin ...

Nature Publishing Group2015

NO binding kinetics in myoglobin investigated by picosecond Fe K-edge absorption spectroscopy

Majed Chergui, Camelia Borca, Frederico Alves Lima, Marco Eli Reinhard, Mercedes Hannelore Rittmann-Frank, Thomas James Penfold, Jochen Rittmann, Mahsa Silatani

Diatomic ligands in hemoproteins and the way they bind to the active center are central to the protein's function. Using picosecond Fe K-edge X-ray absorption spectroscopy, we probe the NO-heme recombination kinetics with direct sensitivity to the Fe-NO bi ...

National Academy of Sciences2015

Characterizing the Structure and Defect Concentration of ZnO Nanoparticles in a Colloidal Solution

Majed Chergui, Camelia Borca, Marco Eli Reinhard, Mercedes Hannelore Rittmann-Frank, Thomas James Penfold, Jochen Rittmann, Thomas Charles Henry Rossi

The structure and defect concentration of colloidal solutions of ZnO nanoparticles, synthesized by a sol gel procedure (SG-NP), as well as commercially available ZnO nanoparticles (SA-NP) are investigated by UV-vis absorption spectroscopy, transmission ele ...

Amer Chemical Soc2014

{110} Slip with {112} slip traces in bcc Tungsten

Helena Van Swygenhoven, Camelia Borca, Cécile Renée Maria Marichal, Steven Van Petegem

While propagation of dislocations in body centered cubic metals at low temperature is understood in terms of elementary steps on {110} planes, slip traces correspond often with other crystallographic or non-crystallographic planes. In the past, characteriz ...

Nature Publishing Group2013

Beam-induced oxidation of monomeric U(IV) species

Camelia Borca, Rizlan Bernier-Latmani, Daniel Scott Alessi, Benjamin Uster

Uranium L-III-edge X-ray absorption spectroscopy is often used to probe the oxidation state and coordination of uranium in environmental samples, and micrometre-sized beams can be used to spatially map the distribution of uranium relative to other elements ...

International Union of Crystallography2013

Slip in directionally solidified Mo-alloy micropillars-Part II: Pillars containing defects

Helena Van Swygenhoven, Camelia Borca, Steven Van Petegem

In situ Laue analysis during microcompression is carried out on Mo-alloy pillars containing defects due to focused ion beam milling or pre-strain. Independently of how the defects are introduced, if the diffraction peaks are streaked prior to deformation, ...

2012

Slip in directionally solidified Mo-alloy micropillars - Part I: Nominally dislocation-free pillars

Helena Van Swygenhoven, Camelia Borca, Cécile Hébert, Barbora Bártová, Emad Oveisi, Cécile Renée Maria Marichal, Steven Van Petegem

In situ Laue analysis during microcompression reveals plasticity in [0 0 1]-oriented, directionally solidified Mo alloy pillars to start with slip on the {1 1 2} < 1 1 1 > system having the highest Schmid factor followed by slip on the (1 1 0) plane contai ...

Elsevier2012

A high-repetition rate scheme for synchrotron-based picosecond laser pump/x-ray probe experiments on chemical and biological systems in solution

Majed Chergui, Frank van Mourik, Camelia Borca, Van Thai Pham, Renske Marjan van der Veen, Frederico Alves Lima, Marco Eli Reinhard, Daniel Grollman, Mercedes Hannelore Rittmann-Frank, Lotta Susanne Karlsson

We present the extension of time-resolved optical pump/x-ray absorption spectroscopy (XAS) probe experiments towards data collection atMHz repetition rates. The use of a high-power picosecond laser operating at an integer fraction of the repetition rate of ...

American Institute of Physics2011

Picosecond Time-Resolved X-Ray Emission Spectroscopy: Ultrafast Spin-State Determination in an Iron Complex

Camelia Borca, Van Thai Pham

Wiley-VCH Verlag GmbH2010

Time-resolved x-ray absorption spectroscopy: Watching atoms dance

Majed Chergui, Paul Beaud, Wojciech Gawelda, Camelia Borca, Amal El Nahhas, Van Thai Pham, Renske Marjan van der Veen, Frederico Alves Lima

The introduction of pump-probe techniques to the field of x-ray absorption spectroscopy (XAS) has allowed the monitoring of both structural and electronic dynamics of disordered systems in the condensed phase with unprecedented accuracy, both in time and i ...

Iop Publishing Ltd, Dirac House, Temple Back, Bristol Bs1 6Be, England2009

Microprobe analysis of neutron irradiated and autoclaved zirconium niobium claddings using synchrotron-based hard X-ray imaging and spectroscopy

Camelia Borca

Two zirconium alloys (Zr-2.5%Nb) - one oxidized in a pressurized water reactor, the other oxidized in autoclave and used as reference - are analyzed by combining synchrotron-based scanning transmission and fluorescence X-ray microscopy and micro-X-ray abso ...

Elsevier2009

Retrieving photochemically active structures by time-resolved EXAFS spectroscopy

Majed Chergui, Wojciech Gawelda, Camelia Borca, Amal El Nahhas, Van Thai Pham, Renske Marjan van der Veen, Frederico Alves Lima

Describing the nature and structure of molecular excited states is important in order to understand their chemical reactivity and role as intermediates in photochemical reactions. The recent implementation of x-ray absorption spectroscopy in the ultrafast ...

Iop Publishing Ltd, Dirac House, Temple Back, Bristol Bs1 6Be, England2009

Femtosecond XANES Study of the Light-Induced Spin Crossover Dynamics in an Iron(II) Complex

Majed Chergui, Paul Beaud, Wojciech Gawelda, Camelia Borca, Amal El Nahhas, Van Thai Pham, Renske Marjan van der Veen

X-ray absorption spectroscopy is a powerful probe of mol. structure, but it has previously been too slow to track the earliest dynamics after photoexcitation. We investigated the ultrafast formation of the lowest quintet state of aq. iron(II) tris(bipyridi ...

American Association for the Advancement of Science2009

H+ implanted channel waveguides in buried epitaxial crystalline YAG:Nd, Tm layers and infrared-to-blue upconversion characterization

Camelia Borca

Nd, Tm:YAG codoped single crystal waveguides were studied in order to discover if the presence of Nd3+ ions favors blue luminescence at 486 nm. Innovative implantation techniques were applied to locally change Delta n and form varied H+ implanted channel s ...

2008

EXAFS structural determination of the Pt2(P2O5H2)44- anion in solution

Majed Chergui, Camelia Borca, Amal El Nahhas, Van Thai Pham, Renske Marjan van der Veen

We present the first structural detn. of the Pt2(P2O5H2)44- anion in soln. by analyzing the extended X-ray absorption fine structure (EXAFS) spectrum of the Pt LIII edge. The data could be fit with a simple model involving single and multiple scattering pa ...

2008

Lu, Gd codoped KY(WO4)(2): Yb epitaxial layers: towards integrated optics based on KY(WO4)(2)

René Salathé, Yaroslav Romanyuk, Camelia Borca

2007

Buried channel waveguides in Yb-doped KY(WO4)2 crystals fabricated by femtosecond laser irradiation

Hans Georg Limberger, René Salathé, Camelia Borca

Elsevier2007