124 research outputs found
Well-defined metal-polymer nanocomposites: The interplay of structure, thermoplasmonics, and elastic mechanical properties
High-Temperature Thermal Transport in Porous Silica Materials : Direct Observation of a Switch from Conduction to Radiation
Direct Measurement of the In-Plane Thermal Diffusivity of Semitransparent Thin Films by Lock-In Thermography : An Extension of the Slopes Method
Response to âComment on âHigh-Temperature Thermal Transport in Porous Silica Materials: Direct Observation of a Switch from Conduction to Radiationââ
Vibrational dynamics of a two-dimensional microgranular crystal
We study the dynamics of an ordered hexagonal monolayer of polystyrene microspheres adhered to a glass substrate coated with a thin aluminum layer. A laser-induced transient grating technique is employed to generate and detect three types of acoustic modes across the entire Brillouin zone in the ÎâK direction: low-frequency contact-based modes of the granular monolayer, high-frequency modes originating from spheroidal vibrations of the microspheres, and surface Rayleigh waves. The dispersion relation of contact-based and spheroidal modes indicates that they are collective modes of the microgranular crystal controlled by particle-particle contacts. We observe a spheroidal resonance splitting caused by the symmetry breaking due to the substrate, as well as an avoided crossing between the Rayleigh and spheroidal modes. The measurements are found to be in agreement with our analytical model.United States. Department of Energy (Grant DE-FG02-00ER15087)National Science Foundation (U.S.) (Grant CHE-1111557
Smectic ordering in liquid crystal - aerosil dispersions II. Scaling analysis
Liquid crystals offer many unique opportunities to study various phase
transitions with continuous symmetry in the presence of quenched random
disorder (QRD). The QRD arises from the presence of porous solids in the form
of a random gel network. Experimental and theoretical work support the view
that for fixed (static) inclusions, quasi-long-range smectic order is destroyed
for arbitrarily small volume fractions of the solid. However, the presence of
porous solids indicates that finite-size effects could play some role in
limiting long-range order. In an earlier work, the nematic - smectic-A
transition region of octylcyanobiphenyl (8CB) and silica aerosils was
investigated calorimetrically. A detailed x-ray study of this system is
presented in the preceding Paper I, which indicates that pseudo-critical
scaling behavior is observed. In the present paper, the role of finite-size
scaling and two-scale universality aspects of the 8CB+aerosil system are
presented and the dependence of the QRD strength on the aerosil density is
discussed.Comment: 14 pages, 10 figures, 1 table. Companion paper to "Smectic ordering
in liquid crystal - aerosil dispersions I. X-ray scattering" by R.L. Leheny,
S. Park, R.J. Birgeneau, J.-L. Gallani, C.W. Garland, and G.S. Iannacchion
Highly Effective Cystic Fibrosis Clinical Research Teams: Critical Success Factors
BACKGROUND Bringing new therapies to patients with rare diseases depends in part on optimizing clinical trial conduct through efficient study start-up processes and rapid enrollment. Suboptimal execution of clinical trials in academic medical centers not only results in high cost to institutions and sponsors, but also delays the availability of new therapies. Addressing the factors that contribute to poor outcomes requires novel, systematic approaches tailored to the institution and disease under study. OBJECTIVE To use clinical trial performance metrics data analysis to select high-performing cystic fibrosis (CF) clinical research teams and then identify factors contributing to their success. DESIGN Mixed-methods research, including semi-structured qualitative interviews of high-performing research teams. PARTICIPANTS CF research teams at nine clinical centers from the CF Foundation Therapeutics Development Network. APPROACH Survey of site characteristics, direct observation of team meetings and facilities, and semi-structured interviews with clinical research team members and institutional program managers and leaders in clinical research. KEY RESULTS Critical success factors noted at all nine high-performing centers were: 1) strong leadership, 2) established and effective communication within the research team and with the clinical care team, and 3) adequate staff. Other frequent characteristics included a mature culture of research, customer service orientation in interactions with study participants, shared efficient processes, continuous process improvement activities, and a businesslike approach to clinical research. CONCLUSIONS Clinical research metrics allowed identification of high-performing clinical research teams. Site visits identified several critical factors leading to highly successful teams that may help other clinical research teams improve clinical trial performance
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