MESA+ publications last 4 weeks

Record 1 of 32

Title: Controlling the quality factor of a tuning-fork resonance between 9 and 300 K for scanning-probe microscopy

Author(s): Ctistis, G (Ctistis, G.); Frater, EH (Frater, E. H.); Huisman, SR (Huisman, S. R.); Korterik, JP (Korterik, J. P.); Herek, JL (Herek, J. L.); Vos, WL (Vos, W. L.); Pinkse, PWH (Pinkse, P. W. H.)

Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS  Volume: 44  Issue: 37  Article Number: 375502  DOI: 10.1088/0022-3727/44/37/375502  Published: SEP 21 2011  

Abstract: We study the dynamic response of a mechanical quartz tuning fork in the temperature range from 9 to 300 K. Since the quality factor Q of the resonance strongly depends on temperature, we implement a procedure to control the quality factor of the resonance. We show that we are able to dynamically change the quality factor and keep it constant over the whole temperature range. This procedure is suitable for applications in scanning-probe microscopy.

ISSN: 0022-3727

Record 2 of 32

Title: Pushing membrane stability boundaries with HybSi (R) pervaporation membranes

Author(s): van Veen, HM (van Veen, Henk M.); Rietkerk, MDA (Rietkerk, Marielle D. A.); Shanahan, DP (Shanahan, Donough P.); van Tuel, MMA (van Tuel, Marc M. A.); Kreiter, R (Kreiter, Robert); Castricum, HL (Castricum, Hessel L.); ten Elshof, JE (ten Elshof, Johan E.); Vente, JF (Vente, Jaap F.)

Source: JOURNAL OF MEMBRANE SCIENCE  Volume: 380  Issue: 1-2  Pages: 124-131  DOI: 10.1016/j.memsci.2011.06.040  Published: SEP 15 2011  

Abstract: To overcome the limitations of currently available commercial polymer and zeolite membranes for pervaporation applications, a hybrid silica membrane (HybSi (R)) has been developed. In this paper the unprecedented stability of HybSi (R) membrane technology for the dehydration of organic solvents is reported. It is shown that the HybSi (R) membranes are suitable for demanding separations using pervaporation at temperatures up to at least 190 degrees C, in aggressive aprotic solvents including N-methyl-2-pyrrolidone (NMP), and down to a pH value of similar to 2. The high hydrothermal and chemical stability was proven in continuous measurements that lasted for periods of months to several years. The longest test, on the dehydration of n-butanol at 150 degrees C, lasted for 1000 days. The high stability parallels high fluxes and selectivities that meet current industrial demands and expectations. After a period of stabilization, fluxes and selectivities become constant. The presented results show that HybSi (R) membranes are widely applicable in the dehydration of organic solvents by pervaporation. (C) 2011 Elsevier B.V. All rights reserved.

ISSN: 0376-7388

Record 3 of 32

Title: Cavity sideband cooling of trapped molecules

Author(s): Kowalewski, M (Kowalewski, Markus); Morigi, G (Morigi, Giovanna); Pinkse, PWH (Pinkse, Pepijn W. H.); de Vivie-Riedle, R (de Vivie-Riedle, Regina)

Source: PHYSICAL REVIEW A  Volume: 84  Issue: 3  Article Number: 033408  DOI: 10.1103/PhysRevA.84.033408  Published: SEP 12 2011  

Abstract: The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case in which the infrared transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped either by a radiofrequency or optical trapping potential, depending on whether they are charged or neutral, and confined inside a high-finesse optical resonator that enhances radiative emission into the cavity mode. Using realistic experimental parameters and COS as a representative molecular example, we show that in this setup, cooling to the trap ground state is feasible.

ISSN: 1050-2947

Record 4 of 32

Title: Development of Nanoscale Inhomogeneities during Drying of Sol-Gel Derived Amorphous Lead Zirconate Titanate Precursor Thin Films

Author(s): Stawski, TM (Stawski, Tomasz M.); Veldhuis, SA (Veldhuis, Sjoerd A.); Castricum, HL (Castricum, Hessel L.); Keim, EG (Keim, Enrico G.); Eeckhaut, G (Eeckhaut, Guy); Bras, W (Bras, Wim); Blank, DHA (Blank, Dave H. A.); ten Elshof, JE (ten Elshof, Johan E.)

Source: LANGMUIR  Volume: 27  Issue: 17  Pages: 11081-11089  DOI: 10.1021/la201905t  Published: SEP 6 2011  

Abstract: The structural evolution of sol-gel derived lead zirconate titanate (PZT) precursor films during and after physical drying was investigated by transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), selected area electron diffraction (SAED), and time-resolved X-ray diffraction (XRD). Films were deposited from initial 0.3 mol/dm(3) precursor sols with varying hydrolysis ratios. Zr-rich grains of 1-10 nm size, embedded in a Pb-, Zr-, and Ti-containing amorphous matrix were found in as-dried films. The Zr-rich regions were crystalline at hydrolysis ratios [H(2)O]/[PZT] < 27.6, and amorphous at ratios > 100. X-ray diffraction analysis of PZT and zirconia sols revealed that the crystalline nanoparticles in both sols are identical and are probably composed of nanosized zirconium oxoacetate-like clusters. This study demonstrates that time-resolved X-ray diffraction combined with electron energy loss spectroscopy mapping is a powerful tool to monitor the nanoscale structural evolution of sol-gel derived thin films.

ISSN: 0743-7463

Record 5 of 32

Title: Smart Design of Stripe-Patterned Gradient Surfaces to Control Droplet Motion

Author(s): Bliznyuk, O (Bliznyuk, O.); Jansen, HP (Jansen, H. Patrick); Kooij, ES (Kooij, E. Stefan); Zandvliet, HJW (Zandvliet, Harold J. W.); Poelsema, B (Poelsema, Bene)

Source: LANGMUIR  Volume: 27  Issue: 17  Pages: 11238-11245  DOI: 10.1021/la201671w  Published: SEP 6 2011  

Abstract: The motion of droplets under the influence of lithographically created anisotropic chemically defined patterns is described and discussed. The patterns employed in our experiments consist of stripes of alternating wettability: hydrophobic stripes are created via fluorinated self-assembled monolayers, and for hydrophilic stripes, the SiO(2) substrate is used. The energy gradient required to induce the motion of the droplets is created by varying the relative widths of the stripes in such a way that the fraction of the hydrophilic area increases. The anisotropic patterns create a preferential direction for liquid spreading parallel to the stripes and confine motion to the perpendicular direction, giving rise to markedly higher velocities as compared to nonstructured surface energy gradients. Consequently, the influence of the distinct pattern features on the overall motion as well as suggestions for design improvements from an application point of view are discussed.

ISSN: 0743-7463

Record 6 of 32

Title: Knudsen Gas Provides Nanobubble Stability

Author(s): Seddon, JRT (Seddon, James R. T.); Zandvliet, HJW (Zandvliet, Harold J. W.); Lohse, D (Lohse, Detlef)

Source: PHYSICAL REVIEW LETTERS  Volume: 107  Issue: 11  Article Number: 116101  DOI: 10.1103/PhysRevLett.107.116101  Published: SEP 6 2011  

Abstract: We provide a model for the remarkable stability of surface nanobubbles to bulk dissolution. The key to the solution is that the gas in a nanobubble is of Knudsen type. This leads to the generation of a bulk liquid flow which effectively forces the diffusive gas to remain local. Our model predicts the presence of a vertical water jet immediately above a nanobubble, with an estimated speed of similar to 3.3 m/s, in good agreement with our experimental atomic force microscopy measurement of similar to 2.7 m/s. In addition, our model also predicts an upper bound for the size of nanobubbles, which is consistent with the available experimental data.

ISSN: 0031-9007

Record 7 of 32

Title: Force modulation for enhanced nanoscale electrical sensing

Author(s): Koelmans, WW (Koelmans, W. W.); Sebastian, A (Sebastian, A.); Abelmann, L (Abelmann, L.); Despont, M (Despont, M.); Pozidis, H (Pozidis, H.)

Source: NANOTECHNOLOGY  Volume: 22  Issue: 35  Article Number: 355706  DOI: 10.1088/0957-4484/22/35/355706  Published: SEP 2 2011  

Abstract: Scanning probe microscopy employing conductive probes is a powerful tool for the investigation and modification of electrical properties at the nanoscale. Application areas include semiconductor metrology, probe-based data storage and materials research. Conductive probes can also be used to emulate nanoscale electrical contacts. However, unreliable electrical contact and tip wear have severely hampered the widespread usage of conductive probes for these applications. In this paper we introduce a force modulation technique for enhanced nanoscale electrical sensing using conductive probes. This technique results in lower friction, reduced tip wear and enhanced electrical contact quality. Experimental results using phase-change material stacks and platinum silicide conductive probes clearly demonstrate the efficacy of the proposed technique. Furthermore, conductive-mode imaging experiments on specially prepared platinum/carbon samples are presented to demonstrate the widespread applicability of this technique.

ISSN: 0957-4484

Record 8 of 32

Title: Infrared suppression by hybrid EUV multilayer-IR etalon structures

Author(s): Medvedev, VV (Medvedev, V. V.); Yakshin, AE (Yakshin, A. E.); van de Kruijs, RWE (van de Kruijs, R. W. E.); Krivtsun, VM (Krivtsun, V. M.); Yakunin, AM (Yakunin, A. M.); Koshelev, KN (Koshelev, K. N.); Bijkerk, F (Bijkerk, F.)

Source: OPTICS LETTERS  Volume: 36  Issue: 17  Pages: 3344-3346  Published: SEP 1 2011  

Abstract: We have developed a multilayer mirror for extreme UV (EUV) radiation (13.5nm), which has near-zero reflectance for IR line radiation (10.6 mu m). The EUV reflecting multilayer is based on alternating B(4)C and Si layers. Substantial transparency of these materials with respect to the IR radiation allowed the integration of the multilayer coating in a resonant quarter-wave structure for 10.6 mu m. Samples were manufactured using magnetron sputtering deposition technique and demonstrated suppression of the IR radiation by up to 3 orders of magnitude. The EUV peak reflectance amounts 45% at 13: 5nm, with a bandwidth at FWHM being 0.284 nm. Therefore such a mirror could replace conventional multilayer mirrors to suppress undesired spectral components in monochromatic imaging applications, including EUV photolithography. (C) 2011 Optical Society of America

ISSN: 0146-9592

Record 9 of 32

Title: Phase characterization of the reflection on an extreme UV multilayer: comparison between attosecond metrology and standing wave measurements

Author(s): Loch, RA (Loch, R. A.); Dubrouil, A (Dubrouil, A.); Sobierajski, R (Sobierajski, R.); Descamps, D (Descamps, D.); Fabre, B (Fabre, B.); Lidon, P (Lidon, P.); van de Kruijs, RWE (van de Kruijs, R. W. E.); Boekhout, F (Boekhout, F.); Gullikson, E (Gullikson, E.); Gaudin, J (Gaudin, J.); Louis, E (Louis, E.); Bijkerk, F (Bijkerk, F.); Mevel, E (Mevel, E.); Petit, S (Petit, S.); Constant, E (Constant, E.); Mairesse, Y (Mairesse, Y.)

Source: OPTICS LETTERS  Volume: 36  Issue: 17  Pages: 3386-3388  Published: SEP 1 2011  

Abstract: We characterize the phase shift induced by reflection on a multilayer mirror in the extreme UV range (80-93 eV) using two techniques: one based on high order harmonic generation and attosecond metrology (reconstruction of attosecond beating by interference of two-photon transitions), and a second based on synchrotron radiation and measurements of standing waves (total electron yield). We find an excellent agreement between the results from the two measurements and a flat group delay shift (+/- 40 as) over the main reflectivity peak of the mirror. (C) 2011 Optical Society of America

ISSN: 0146-9592

Record 10 of 32

Title: Anomalous proximity effect in spin-valve superconductor/ferromagnetic metal/ferromagnetic metal structures

Author(s): Karminskaya, TY (Karminskaya, T. Yu); Golubov, AA (Golubov, A. A.); Kupriyanov, MY (Kupriyanov, M. Yu)

Source: PHYSICAL REVIEW B  Volume: 84  Issue: 6  Article Number: 064531  DOI: 10.1103/PhysRevB.84.064531  Published: AUG 26 2011  

Abstract: We investigate superconductor (S) and ferromagnetic metal (F) SFF structures with noncollinear magnetizations of F films with arbitrary FF interface transparency. We show the existence of phase slips at both the SF and FF interfaces, which manifest themselves in the anomalous dependence of the spin-triplet correlations on the misorientation angle between the magnetization vectors in the F layers. We discuss how these effects can be observed in experiments with Josephson pi junctions.

ISSN: 1098-0121

Record 11 of 32

Title: Peptide-Functionalized Luminescent Iridium Complexes for Lifetime Imaging of CXCR4 Expression

Author(s): Kuil, J (Kuil, Joeri); Steunenberg, P (Steunenberg, Peter); Chin, PTK (Chin, Patrick T. K.); Oldenburg, J (Oldenburg, Joppe); Jalink, K (Jalink, Kees); Velders, AH (Velders, Aldrik H.); van Leeuwen, FWB (van Leeuwen, Fijs W. B.)

Source: CHEMBIOCHEM  Volume: 12  Issue: 12  Pages: 1896-1902  DOI: 10.1002/cbic.201100271  Published: AUG 16 2011  

Abstract: The chemokine receptor 4 (CXCR4) is over-expressed in 23 types of cancer in which it plays a role in, among others, the metastatic spread. For this reason it is a potential biomarker for the field of diagnostic oncology. The antagonistic Ac-TZ14011 peptide, which binds to CXCR4, has been conjugated to luminescent iridium dyes to allow for CXCR4 visualization. The iridium dyes are cyclometalated octahedral iridium(III) 2-phenylpyridine complexes that can be functionalized with one, two or three targeting Ac-TZ14011 peptides. Confocal microscopy and fluorescence lifetime imaging microscopy (FLIM) showed that the peptide-iridium complex conjugates can be used to visualize CXCR4 expression in tumor cells. The CXCR4 receptor affinity and specific cell binding of the mono-, di- and trimeric peptide derivatives were assessed by using flow cytometry. The three derivatives possessed nanomolar receptor affinity and could distinguish between cell lines with different CXCR4 expression levels. This yields the first example of a neutral iridium(III) complex functionalized with peptides for FLIM-based visualization of a cancer associated membrane receptor.

ISSN: 1439-4227

Record 12 of 32

Title: Electrochemical Stability of Self-Assembled Alkylphosphate Monolayers on Conducting Metal Oxides

Author(s): Yildirim, O (Yildirim, Oktay); Yilmaz, MD (Yilmaz, M. Deniz); Reinhoudt, DN (Reinhoudt, David N.); Blank, DHA (Blank, Dave H. A.); Rijnders, G (Rijnders, Guus); Huskens, J (Huskens, Jurriaan)

Source: LANGMUIR  Volume: 27  Issue: 16  Pages: 9890-9894  DOI: 10.1021/la200925v  Published: AUG 16 2011  

Abstract: Alkylphosphate self-assembled monolayers (SAMs) were prepared on Nb-doped SrTiO(3) (Nb-STO) conducting metal oxide substrates. Unlike thiols on gold, the alkylphosphate SAMs on Nb-STO exhibited an electrochemical stability over a wide voltage range from -2 to 2 V. Cyclic voltammetry showed that the SAM modification inhibited the electrochemical activity of the underlying conducting substrate with an efficiency dependent on the chain length. Impedance spectroscopy showed that SAM-modified Nb-STO substrates have a significantly higher resistance than bare substrates.

ISSN: 0743-7463

Record 13 of 32

Title: Unconventional Surface Impedance of a Normal-Metal Film Covering a Spin-Triplet Superconductor Due to Odd-Frequency Cooper Pairs

Author(s): Asano, Y (Asano, Yasuhiro); Golubov, AA (Golubov, Alexander A.); Fominov, YV (Fominov, Yakov V.); Tanaka, Y (Tanaka, Yukio)

Source: PHYSICAL REVIEW LETTERS  Volume: 107  Issue: 8  Article Number: 087001  DOI: 10.1103/PhysRevLett.107.087001  Published: AUG 16 2011  

Abstract: We discuss the dynamic response of odd-frequency Cooper pairs to an electromagnetic field. By using the quasiclassical Green function method, we calculate the impedance (Z = R - iX) of a normal-metal thin film which covers a superconductor. In contrast with the standard relation ( i.e., R << X), the impedance in spin-triplet proximity structures shows anomalous behavior ( i.e., R > X) in the low frequency limit. This unusual relation is a result of the penetration of odd-frequency pairs into the normal metal and reflects the negative Cooper pair density.

ISSN: 0031-9007

Record 14 of 32

Title: Predicted photonic band gaps in diamond-lattice crystals built from silicon truncated tetrahedrons

Author(s): Woldering, LA (Woldering, Leon A.); Abelmann, L (Abelmann, Leon); Elwenspoek, MC (Elwenspoek, Miko C.)

Source: JOURNAL OF APPLIED PHYSICS  Volume: 110  Issue: 4  Article Number: 043107  DOI: 10.1063/1.3624604  Published: AUG 15 2011  

Abstract: Recently, a silicon micromachining method to produce tetrahedral silicon particles was discovered. In this report we determine, using band structure calculations, the optical properties of diamond-lattice photonic crystals when assembled from such particles. We show that crystal structures built from silicon tetrahedra are expected to display small stop gaps. Wide photonic band gaps appear when truncated tetrahedral particles are used to build the photonic crystals. With truncated tetrahedral particles, a bandgap with a width of 23.6% can be achieved, which is more than twice as wide compared to band gaps in self-assembled diamond-lattices of hard-spheres. The width of the bandgap is insensitive to small deviations from the optimal amount of truncation. This work paves the way to a novel class of silicon diamond-lattice bandgap crystals that can be obtained through self-assembly. Such a self-assembly approach would allow for easy integration of these highly photonic crystals in existing silicon microfluidic and -electronic systems. (C) 2011 American Institute of Physics. [doi:10.1063/1.3624604]

ISSN: 0021-8979

Record 15 of 32

Title: Tuning a racetrack ring resonator by an integrated dielectric MEMS cantilever

Author(s): Abdulla, SMC (Abdulla, S. M. C.); Kauppinen, LJ (Kauppinen, L. J.); Dijkstra, M (Dijkstra, M.); de Boer, MJ (de Boer, M. J.); Berenschot, E (Berenschot, E.); Jansen, HV (Jansen, H. V.); de Ridder, RM (de Ridder, R. M.); Krijnen, GJM (Krijnen, G. J. M.)

Source: OPTICS EXPRESS  Volume: 19  Issue: 17  Pages: 15864-15878  Published: AUG 15 2011  

Abstract: The principle, fabrication and characterization of a dielectric MEMS cantilever located a few 100 nm above a racetrack ring resonator are presented. After fabrication of the resonators on silicon-on-insulator (SOI) wafers in a foundry process, the cantilevers were integrated by surface micromachining techniques. Off-state deflections of the cantilevers have been optimized to appropriately position them near the evanescent field of the resonator. Using electrostatic actuation, moving the cantilevers into this evanescent field, the propagation properties of the ring waveguide are modulated. We demonstrate 122 pm tuning of the resonance wavelength of the optical ring resonator (in the optical C-band) without change of the optical quality factor, on application of 9 V to a 40 mu m long cantilever. This compact integrated device can be used for tuning/switching a specific wavelength, with very little energy for operation and negligible cross talk with surrounding devices. (C) 2011 Optical Society of America

ISSN: 1094-4087

Record 16 of 32

Title: Modelling the resistive state in a transition edge sensor

Author(s): Kozorezov, A (Kozorezov, A.); Golubov, AA (Golubov, A. A.); Martin, DDE (Martin, D. D. E.); de Korte, PAJ (de Korte, P. A. J.); Lindeman, MA (Lindeman, M. A.); Hijmering, RA (Hijmering, R. A.); van der Kuur, J (van der Kuur, J.); Hoevers, HFC (Hoevers, H. F. C.); Gottardi, L (Gottardi, L.); Kupriyanov, MY (Kupriyanov, M. Yu.); Wigmore, JK (Wigmore, J. K.)

Source: APPLIED PHYSICS LETTERS  Volume: 99  Issue: 6  Article Number: 063503  DOI: 10.1063/1.3621829  Published: AUG 8 2011  

Abstract: We have developed a model for the resistive transition in a transition edge sensor (TES) based on the model of a resistively and capacitively shunted junction, taking into account phase-slips of a superconducting system across the barriers of the tilted washing board potential. We obtained analytical expressions for the resistance of the TES, R(T, I), and its partial logarithmic derivatives alpha(I) and beta(I) as functions of temperature and current. We have shown that all the major parameters describing the resistive state of the TES are determined by the dependence on temperature of the Josephson critical current, rather than by intrinsic properties of the S-N transition. The complex impedance of a pristine TES exhibits two-pole behaviour due to its own intrinsic reactance. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3621829]

ISSN: 0003-6951

Record 17 of 32

Title: Infrared imaging and acoustic sizing of a bubble inside a micro-electro-mechanical system piezo ink channel

Author(s): van der Bos, A (van der Bos, Arjan); Segers, T (Segers, Tim); Jeurissen, R (Jeurissen, Roger); van den Berg, M (van den Berg, Marc); Reinten, H (Reinten, Hans); Wijshoff, H (Wijshoff, Herman); Versluis, M (Versluis, Michel); Lohse, D (Lohse, Detlef)

Source: JOURNAL OF APPLIED PHYSICS  Volume: 110  Issue: 3  Article Number: 034503  DOI: 10.1063/1.3606567  Published: AUG 1 2011  

Abstract: Piezo drop-on-demand inkjet printers are used in an increasing number of applications because of their reliable deposition of droplets onto a substrate. Droplets of a few picoliters are ejected from an inkjet nozzle at frequencies of up to 100 kHz. However, the entrapment of an air microbubble in the ink channel can severely impede the productivity and reliability of the printing system. The air bubble disturbs the channel acoustics, resulting in disrupted drop formation or failure of the jetting process. Here we study a micro-electro-mechanical systems-based printhead. By using the actuating piezo transducer in receive mode, the acoustical field inside the channel was monitored, clearly identifying the presence of an air microbubble inside the channel during failure of the jetting process. The infrared visualization technique allowed for the accurate sizing of the bubble, including its dynamics, inside the intact printhead. A model was developed to calculate the mutual interaction between the channel acoustics and the bubble dynamics. The model was validated by simultaneous acoustical and infrared detection of the bubble. The model can predict the presence and size of entrapped air bubbles inside an operating ink channel purely from the acoustic response. (C) 2011 American Institute of Physics. [doi:10.1063/1.3606567]

ISSN: 0021-8979

Record 18 of 32

Title: Micromolding for ceramic microneedle arrays

Author(s): Bystrova, S (Bystrova, S.); Luttge, R (Luttge, R.)

Source: MICROELECTRONIC ENGINEERING  Volume: 88  Issue: 8  Pages: 1681-1684  DOI: 10.1016/j.mee.2010.12.067  Published: AUG 2011  

Abstract: The fabrication process of ceramic microneedle arrays (MNAs) is presented. This includes the manufacturing of an SU-8/Si-master, its double replication resulting in a PDMS mold for production by micromolding and ceramic sintering. The robustness of the replicated structures was tested by means of microindentation techniques eliminating shear forces and by manual application of MNAs into silicone rubber. No damages of MNAs were observed using controlled microindentation. After the manual application, however, some microneedles were broken and left in the silicone. The opportunities and the ways to solve underlying problems of the fabrication process will be suggested and discussed. (C) 2011 Elsevier B.V. All rights reserved.

ISSN: 0167-9317

Record 19 of 32

Title: Influence of silicon orientation and cantilever undercut on the determination of the Young's modulus of thin films

Author(s): Nazeer, H (Nazeer, H.); Woldering, LA (Woldering, L. A.); Abelmann, L (Abelmann, L.); Nguyen, MD (Nguyen, M. D.); Rijnders, G (Rijnders, G.); Elwenspoek, MC (Elwenspoek, M. C.)

Source: MICROELECTRONIC ENGINEERING  Volume: 88  Issue: 8  Pages: 2345-2348  DOI: 10.1016/j.mee.2011.01.028  Published: AUG 2011  

Abstract: The Young's modulus of thin films can be determined by deposition on a micronsized Si cantilever and measuring the resonance frequency before and after deposition. The accuracy of the method depends strongly on the initial determination of the mechanical properties and dimensions of the cantilever. We discuss the orientation of the cantilever with respect to the Si crystal, and the inevitable undercut of the cantilever caused by process inaccuracies. By finite element modelling we show that the Young's modulus should be used instead of the analytical plate modulus approximation for the effective Young's modulus of Si cantilevers used in this work for both the < 1 0 0 > and < 1 1 0 > crystal orientation. Cantilever undercut can be corrected by variation of the cantilever length. As an example, the Young's modulus of PbZr(0.52)Ti(0.48)O(3) (PZT) thin films deposited by pulsed laser deposition (PLO) was determined to be 99 GPa, with 1.4 GPa standard error. (C) 2011 Elsevier B.V. All rights reserved.

ISSN: 0167-9317

Record 20 of 32

Title: Collective oscillations in bubble clouds

Author(s): Zeravcic, Z (Zeravcic, Zorana); Lohse, D (Lohse, Detlef); Van Saarloos, W (Van Saarloos, Wim)

Source: JOURNAL OF FLUID MECHANICS  Volume: 680  Pages: 114-149  DOI: 10.1017/jfm.2011.153  Published: AUG 2011  

Abstract: In this paper the collective oscillations of a bubble cloud in an acoustic field are theoretically analysed with concepts and techniques of condensed matter physics. More specifically, we will calculate the eigenmodes and their excitabilities, eigenfrequencies, densities of states, responses, absorption and participation ratios to better understand the collective dynamics of coupled bubbles and address the question of possible localization of acoustic energy in the bubble cloud. The radial oscillations of the individual bubbles in the acoustic field are described by coupled linearized Rayleigh-Plesset equations. We explore the effects of viscous damping, distance between bubbles, polydispersity, geometric disorder, size of the bubbles and size of the cloud. For large enough clusters, the collective response is often very different from that of a typical mode, as the frequency response of each mode is sufficiently wide that many modes are excited when the cloud is driven by ultrasound. The reason is the strong effect of viscosity on the collective mode response, which is surprising, as viscous damping effects are small for single-bubble oscillations in water. Localization of acoustic energy is only found in the case of substantial bubble size polydispersity or geometric disorder. The lack of localization for a weak disorder is traced back to the long-range 1/r interaction potential between the individual bubbles. The results of the present paper are connected to recent experimental observations of collective bubble oscillations in a two-dimensional bubble cloud, where pronounced edge states and a pronounced low-frequency response had been observed, both consistent with the present theoretical findings. Finally, an outlook to future possible experiments is given.

ISSN: 0022-1120

Record 21 of 32

Title: Hierarchical Self-Assembly and Optical Disassembly for Controlled Switching of Magnetoferritin Nanoparticle Magnetism

Author(s): Kostiainen, MA (Kostiainen, Mauri A.); Ceci, P (Ceci, Pierpaolo); Fornara, M (Fornara, Manuela); Hiekkataipale, P (Hiekkataipale, Panu); Kasyutich, O (Kasyutich, Oksana); Nolte, RJM (Nolte, Roeland J. M.); Cornelissen, JJLM (Cornelissen, Jeroen J. L. M.); Desautels, RD (Desautels, Ryan D.); van Lierop, J (van Lierop, Johan)

Source: ACS NANO  Volume: 5  Issue: 8  Pages: 6394-6402  DOI: 10.1021/nn201571y  Published: AUG 2011  

Abstract: Protein cages such as ferritin and viral capsids are interesting building blocks for nanotechnology due to their monodisperse structure and ability to encapsulate various functional moieties. Here we show that recombinant ferritin protein cages encapsulating Fe3O4-gamma-Fe2O3 iron oxide (magnetoferritin) nanoparticles and photodegradable Newkome-type dendrons self-assemble Into micrometer-sized complexes with a face-centered-cubic (fcc) superstructure and a lattice constant of 13.1 nm. The magnetic properties of the magnetoferritin particles are affected directly by the hierarchical organization. Magnetoferritin nanoparticles dispersed in water exhibit typical. magnetism of single domain noninteracting nanoparticles; however, the same nanoparticles organized into fcc superstructures show clearly the effects of the altered magnetostatic (e.g., dipole-dipole) interactions by exhibiting, for example, different hysteresis of the field-dependent magnetization. The magnetoferritin-dendron assemblies can be efficiently disassembled by a short optical stimulus resulting In release of free magnetoferritin particles. After the triggered release the nanomagnetic properties of the pristine magnetoferritin nanoparticles are regained.

ISSN: 1936-0851

Record 22 of 32

Title: Determination of critical island size in para-sexiphenyl islands on SiO(2) using capture-zone scaling

Author(s): Lorbek, S (Lorbek, S.); Hlawacek, G (Hlawacek, G.); Teichert, C (Teichert, C.)

Source: EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS  Volume: 55  Issue: 2  Article Number: 23902  DOI: 10.1051/epjap/2011100428  Published: AUG 2011  

Abstract: One of the important parameters in understanding the mechanism of the early stage of organic thin-film growth is the critical nucleus size i*. Here, submonolayer films of para-sexiphenyl grown on amorphous silicon dioxide substrates were investigated by means of atomic-force microscopy and have been analyzed using the recently proposed capture-zone scaling. Applying the generalized Wigner surmise we determine from the capture-zone distribution i* at room temperature and 373 K. The results are compared to traditional analysis by island-size scaling and the applicability of the capture-zone scaling is critically discussed with respect to island shape.

ISSN: 1286-0042

Record 23 of 32

Title: Integrin-dependent activation of the JNK signaling pathway in live cells by mechanical stress

Author(s): Pereira, AM (Maria Pereira, Andrea); Tudor, C (Tudor, Cicerone); Kanger, JS (Kanger, Johannes S.); Martin-Blanco, E (Martin-Blanco, Enrique); Subramaniam, V (Subramaniam, Vinod)

Source: EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS  Volume: 40  Pages: 130-130  Supplement: 1  Published: AUG 2011  

Conference: 8th EBSA European Biophysics Congress Budapest, HUNGARY AUG 23-27, 2011 Hungarian Biophys Soc European Biophys Soc Assoc

Conference Title: 8th EBSA European Biophysics Congress

Conference Date: AUG 23-27, 2011

Conference Location: Budapest, HUNGARY

Conference Sponsor(s): Hungarian Biophys Soc, European Biophys Soc Assoc

ISSN: 0175-7571

Record 24 of 32

Title: Establishing the composition of alpha-synuclein oligomers using single-molecule photobleaching

Author(s): Zijlstra, N (Zijlstra, Niels); Blum, C (Blum, Christian); Segers-Nolten, I (Segers-Nolten, Ine); Claessens, M (Claessens, Mireille); Subramaniam, V (Subramaniam, Vinod)

Source: EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS  Volume: 40  Pages: 224-224  Supplement: 1  Published: AUG 2011  

Conference: 8th EBSA European Biophysics Congress Budapest, HUNGARY AUG 23-27, 2011 Hungarian Biophys Soc European Biophys Soc Assoc

Conference Title: 8th EBSA European Biophysics Congress

Conference Date: AUG 23-27, 2011

Conference Location: Budapest, HUNGARY

Conference Sponsor(s): Hungarian Biophys Soc, European Biophys Soc Assoc

ISSN: 0175-7571

Record 25 of 32

Title: Mechanistic insights into oligomeric alpha-synuclein/membrane interactions

Author(s): Stefanovic, AND (Stefanovic, Anja N. D.); Stockl, MT (Stockl, Martin T.); Claessens, MMAE (Claessens, Mireille M. A. E.); Subramaniam, V (Subramaniam, Vinod)

Source: EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS  Volume: 40  Pages: 93-93  Supplement: 1  Published: AUG 2011  

Conference: 8th EBSA European Biophysics Congress Budapest, HUNGARY AUG 23-27, 2011 Hungarian Biophys Soc European Biophys Soc Assoc

Conference Title: 8th EBSA European Biophysics Congress

Conference Date: AUG 23-27, 2011

Conference Location: Budapest, HUNGARY

Conference Sponsor(s): Hungarian Biophys Soc, European Biophys Soc Assoc

ISSN: 0175-7571

Record 26 of 32

Title: Alpha-synuclein oligomers impair membrane integrity-a mechanistic view

Author(s): Stockl, MT (Stockl, Martin T.); Claessens, MMAE (Claessens, Mireille M. A. E.); Subramaniam, V (Subramaniam, Vinod)

Source: EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS  Volume: 40  Pages: 93-94  Supplement: 1  Published: AUG 2011  

Conference: 8th EBSA European Biophysics Congress Budapest, HUNGARY AUG 23-27, 2011 Hungarian Biophys Soc European Biophys Soc Assoc

Conference Title: 8th EBSA European Biophysics Congress

Conference Date: AUG 23-27, 2011

Conference Location: Budapest, HUNGARY

Conference Sponsor(s): Hungarian Biophys Soc, European Biophys Soc Assoc

ISSN: 0175-7571

Record 27 of 32

Title: Integrated mechano-optical hydrogen gas sensor using cantilever bending readout with a Si(3)N(4) grated waveguide

Author(s): Pham, SV (Pham, So V.); Dijkstra, M (Dijkstra, Meindert); van Wolferen, HAGM (van Wolferen, Henk A. G. M.); Pollnau, M (Pollnau, Markus); Krijnen, GJM (Krijnen, Gijs J. M.); Hoekstra, HJWM (Hoekstra, Hugo J. W. M.)

Source: OPTICS LETTERS  Volume: 36  Issue: 15  Pages: 3003-3005  Published: AUG 1 2011  

Abstract: We demonstrate a proof of concept of a novel and compact integrated mechano-optical sensor for H(2) detection based on a microcantilever suspended above a Si(3)N(4) grated waveguide. The fabricated devices are mechanically and optically modeled and characterized. Sensing operation of the sensor is demonstrated with 1% H(2) in N(2). The error in detection of the cantilever bending induced by absorption of H(2) is estimated to be approximately 10 nm. Significantly improved sensitivity (down to similar to 33 pm) is expected for reduced initial bending of the microcantilever. The simulation and experimental results are in good agreement and provide a good guideline for further optimization of the sensor. (C) 2011 Optical Society of America

ISSN: 0146-9592

Record 28 of 32

Title: Electrowetting driven optical switch and tunable aperture

Author(s): Murade, CU (Murade, C. U.); Oh, JM (Oh, J. M.); van den Ende, D (van den Ende, D.); Mugele, F (Mugele, F.)

Source: OPTICS EXPRESS  Volume: 19  Issue: 16  Pages: 15525-15531  Published: AUG 1 2011  

Abstract: We demonstrate an electrowetting based optical switch with tunable aperture. Under the influence of an electric field a non-transparent oil film can be replaced locally by a transparent water drop creating an aperture through which light can pass. Its diameter can be tuned between 0.2 and 1.2 mm by varying the driving voltage or frequency. The on and off response time of the switch is in the order of 2 and 120 ms respectively. Finally we demonstrate an array of switchable apertures that can be tuned independently or simultaneously. (C) 2011 Optical Society of America

ISSN: 1094-4087

Record 29 of 32

Title: Performance and stability of niobium-substituted Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-delta) membranes

Author(s): Fang, SM (Fang, S. M.); Yoo, CY (Yoo, C. -Y.); Bouwmeester, HJM (Bouwmeester, H. J. M.)

Source: SOLID STATE IONICS  Volume: 195  Issue: 1  Pages: 1-6  DOI: 10.1016/j.ssi.2011.05.022  Published: JUL 28 2011  

Abstract: The phase stability, thermal expansion, electrical conductivity, and oxygen permeation of perovskite-type oxides Ba(0.5)Sr(0.5)(Co(0.8)Fe(0.2))(1-x)Nb(x)O(3-delta) (x=0-0.2) have been investigated. Room-temperature X-ray diffraction of as-prepared powders indicates that in the investigated compositional range solid solutions are formed. Long-term annealing experiments both in flowing air and nitrogen, at 750 degrees C, demonstrate that the phase instability observed in parent Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-delta) (BSCF) is suppressed already at the minimum substitution of 5 mol% of niobium for (Co, Fe). Both electrical conductivity and thermal expansion are found to decrease with increasing niobium concentration, which behaviors can be explained by defect chemical considerations, taking into account charge compensation mechanisms by doping BSCF with Nb(5+) donor cations. The oxygen permeation flux of 10 mol% Nb-substituted BSCF, in the range 800-900 degrees C, is reduced by 10% relative to that found for parent BSCF. Switching from helium to a CO(2)-containing purge gas results in a severe reduction or cessation of the oxygen flux. Options are discussed to avoid undesired formation of surface carbonates. (C) 2011 Elsevier B.V. All rights reserved.

ISSN: 0167-2738

Record 30 of 32

Title: Probing Multivalent Interactions in a Synthetic Host-Guest Complex by Dynamic Force Spectroscopy

Author(s): Gomez-Casado, A (Gomez-Casado, Alberto); Dam, HH (Dam, Henk H.); Yilmaz, MD (Yilmaz, M. Deniz); Florea, D (Florea, Daniel); Jonkheijm, P (Jonkheijm, Pascal); Huskens, J (Huskens, Jurriaan)

Source: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY  Volume: 133  Issue: 28  Pages: 10849-10857  DOI: 10.1021/ja2016125  Published: JUL 20 2011  

Abstract: Multivalency is present in many biological and synthetic systems. Successful application of multivalency depends on a correct understanding of the thermodynamics and kinetics of this phenomenon. In this Article, we address the stability and strength of multivalent bonds with force spectroscopy techniques employing a synthetic adamantane/beta-cyclodextrin model system. Comparing the experimental findings to theoretical predictions for the rupture force and the kinetic off-rate, we find that when the valency of the complex is increased from mono- to di- to trivalent, there is a transition from quasi-equilibrium, with a constant rupture force of 99 pN, to a kinetically dependent state, with loading-rate-dependent rupture forces from 140 to 184 pN (divalent) and 175 to 210 pN (trivalent). Additional binding geometries, parallel monovalent ruptures, single-bound divalent ruptures, and single- and double-bound trivalent ruptures are identified. The experimental kinetic off-rates of the multivalent complexes show that the stability of the complexes is significantly enhanced with the number of bonds, in agreement with the predictions of a noncooperative multivalent model.

ISSN: 0002-7863

Record 31 of 32

Title: Monolithic distributed Bragg reflector cavities in Al(2)O(3) with quality factors exceeding 10(6)

Author(s): Bernhardi, EH (Bernhardi, E. H.); Lu, Q (Lu, Q.); van Wolferen, HAGM (van Wolferen, H. A. G. M.); Worhoff, K (Worhoff, K.); de Ridder, RM (de Ridder, R. M.); Pollnau, M (Pollnau, M.)

Source: PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS  Volume: 9  Issue: 3  Pages: 225-234  DOI: 10.1016/j.photonics.2011.03.001  Published: JUL 2011  

Abstract: The design, fabrication, and characterization of surface relief Bragg gratings integrated with aluminum oxide ridge waveguides are reported. After patterning a photoresist layer by laser interference lithography, uniform gratings with a depth of similar to 120 nm and a period of 507 nm were etched into the SiO(2) top cladding. The grating length varied between 1.25 mm and 4.75 mm. The grating-induced loss was 0.08 +/- 0.01 dB/cm, while the maximum grating reflectivity exceeded 99%. These values enabled the realization of monolithic distributed Bragg reflector cavities with finesse up to 147 and quality factors of more than 1.0 x 10(6). The measured performance agrees very well with predictions based on coupled mode theory. (C) 2011 Elsevier B.V. All rights reserved.

ISSN: 1569-4410

Record 32 of 32

Title: Optimized Deep UV Curing Process for Metal-Free Dry-Etching of Critical Integrated Optical Devices

Author(s): Sengo, G (Sengo, G.); Wolferen, HAGM (van Wolferen, H. A. G. M.); Driessen, A (Driessen, A.)

Source: JOURNAL OF THE ELECTROCHEMICAL SOCIETY  Volume: 158  Issue: 10  Pages: H1084-H1089  DOI: 10.1149/1.3623584  Published: 2011  

Abstract: In this paper we present results of Deep UV-curing of resist followed by thermal treatment at temperatures up to 280 degrees C. The curing process was optimized for positive resist profiles of Fujifilm with thicknesses from 0.3 to 3.0 mu m. The procedure was for the first time employed to etch critical optical structures in silicon oxynitride. Furthermore, the effect of this resist treatment on the geometry and quality of the etched profiles in silicon, silicon oxide, silicon nitride, and silicon oxynitride, having dimensions as typically applied in integrated optical devices, was studied. Channel waveguides with steep and smooth sidewalls were realized, without usage of a metal hard mask which would reduce the optical performance, at high etch selectivity (up to 6) for the materials under investigation. The reliable fabrication of various integrated optical structures with critical dimensions, like sub-micron gaps between adjacent waveguide channels, was demonstrated. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3623584] All rights reserved.

ISSN: 0013-4651