Biological processes often take place at surfaces of proteins, where the dynamic and structural properties of aqueous solvents are modified. Information about solvent properties including hydration dynamics and structure, and protein collective motions can be obtained by measuring directly the dielectric response in the megahertz to terahertz frequencies of aqueous protein solutions. Due to the strong absorption of water in this frequency range, the experiment is challenging. Our home built dielectric spectrometer using a vector network analyzer together with frequency extenders allows us to perform the experiment in a wide range of frequency from megahertz to terahertz with a high dynamical range up to 120 dB. A detailed investigation of the dielectric response has revealed the hydration structure including the tightly, loosely bound layers and the number of water molecules in each hydration layer. These water molecules relax with different time constants at different temperatures. As a result, the dynamics of hydrated protein is also probed at different temperatures. Understanding the hydration structure and dynamics of lysozyme in biological conditions can explain the enzymatic activities of biomolecules.
Knowledge of bidirectional reflectance angular distribution of low reflectivity surfaces is important for predicting
stray light in optical systems. We have performed bidirectional reflectance distribution measurements at wavelengths
of 633 nm and 850 nm for surfaces coated with Z302, a commercial optical coating material widely used in optical
instruments. The bidirectional reflectance properties of these surfaces depend on surface topology characterized by
thickness and roughness parameters. To explain our results, we have employed directional scatter analysis of the
experimental data that can be represented by a linear combination of diffuse, glossy, and specular, components.
Modeling the bidirectional reflectance distribution in the context of a ray-trace can provide important information of
stray light, coated surfaces, and their impact on performance of optical instruments.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.