@article{neupane_chase_zhao_wang_he_2021, title={Optical properties of segmented Ag-Au wire at single particle level studied with a home-built micro-spectrometer}, ISSN={["2577-8196"]}, DOI={10.1002/eng2.12439}, abstractNote={Nanomaterials having hetero‐metallic junctions are being explored for sensing, catalytic, and biomedical applications. Insight into the bimetallic junction at nanoscale is important from both fundamental and application perspectives. In this study, we synthesized segmented Au–Ag wire by sequentially electroplating Au and Ag in cylindrical pores in anodic alumina membrane filters. We probed the one photon, two photon, and second harmonic signal in Au–Ag wire at single particle level by focusing laser beam to a diffraction limited spot using a home‐built sample scanning type micro‐spectrometer. When exciting the Au–Ag junctions into the mid‐UV range using two‐photon excitation, we observed two luminescence peaks at 455 and 520 nm, respectively, possibly because of the surface plasmon resonances supported by the sharp boundary and granular nanostructures on the Au–Ag interface. Interestingly, we also observed intense second harmonic generation (SHG) signal from the junction with a yield more than two orders of magnitude higher than that from the Au tips. The SHG intensity as a function of excitation wavelength showed a similar trend to the two‐photon excited luminescence emission spectrum, indicating that the SHG signal was enhanced in the presence of optical resonances. The observation of enhanced radiative properties of the bimetallic junction in the suggested that the Au–Ag wire may serve as an excellent imaging probe or single particle sensors.}, journal={ENGINEERING REPORTS}, author={Neupane, Bhanu B. and Chase, Thomas E. and Zhao, Luyang and Wang, Gufeng and He, Lin}, year={2021}, month={Jul} }
 @article{zheng_elefteriadou_chase_schroeder_sisiopiku_2016, title={Pedestrian Traffic Operations in Urban Networks}, volume={15}, ISSN={["2352-1465"]}, DOI={10.1016/j.trpro.2016.06.012}, abstractNote={The pedestrian mode is an important component of urban networks, and greatly affects the performance of the sidewalks and crosswalks, as well as the entire network traffic operations by interacting with other traffic modes (automobile, bicycle, transit). There have been many studies concerning different aspects of pedestrian behaviors, such as pedestrian walking speed, pedestrian delay, gap acceptance, signal compliance, route choice, etc. The Highway Capacity Manual (HCM) included the pedestrian mode in the HCM 1994 (update to the HCM 1985) and the HCM, 2010 provided several basic technical methodologies for evaluating the pedestrian level of service (LOS) of different urban street facilities. However, it does not fully cover the pedestrian operation in a great detail and it is missing some important findings in recent studies. The objective of this paper is to provide an overview of pedestrian operations in urban networks, to identify the important aspects of pedestrian operation analysis and to provide recommendations for pedestrian facilities in the HCM on the basis of a summary of available U.S. and international literature. The following topics will be discussed: pedestrian movement models, pedestrian delay estimation, pedestrian-vehicle interactions, and pedestrian travel time estimation. The major features of pedestrian movement along urban segments are the walking speed and available space, which were well examined in past studies. Pedestrian delay is one important measure of pedestrian operation, and its estimation models at signalized/unsignalized intersections are presented with respect to different scenarios. Modifications to the delay model in the HCM, 2010 are highlighted. Pedestrian-vehicle interactions highly affect traffic operations. Both driver and pedestrian behaviors in such an interaction were observed in the field and were examined quantitatively. Pedestrian jaywalking behavior was also observed and its impact on traffic is discussed. Pedestrian route choice at the strategic level and crossing location selection at the operational level jointly determine the pedestrian moving path and further affect the travel time at path-level. A model for estimating pedestrian travel time in an urban network is developed and presented. Such a model can be used to evaluate the facility performance as well as serve for pedestrian route selection. This paper identifies the important aspects of pedestrian operation analysis in an urban network and provides several recommendations to the HCM.}, journal={INTERNATIONAL SYMPOSIUM ON ENHANCING HIGHWAY PERFORMANCE (ISEHP), (7TH INTERNATIONAL SYMPOSIUM ON HIGHWAY CAPACITY AND QUALITY OF SERVICE, 3RD INTERNATIONAL SYMPOSIUM ON FREEWAY AND TOLLWAY OPERATIONS)}, author={Zheng, Yinan and Elefteriadou, Lily and Chase, Thomas and Schroeder, Bastian and Sisiopiku, Virginia}, year={2016}, pages={137–149} }
 @article{zheng_chase_he_2014, title={Multiplexed miRNA detection using cationic polythiophene}, volume={6}, ISSN={["1759-9679"]}, DOI={10.1039/c3ay41752b}, abstractNote={Detection of short strands of miRNA has significant biomedical and biological implications. We report here the integration of fluorescent conjugated polymers as detection moieties with metallic striped nanorods for multiplexed detection of miR-21 and miR-122 in solution. Specifically, cationic conjugated polymers were used as chemical-coupling-free signal reporters to indicate the presence of specific miRNA molecules in solution and nanorods with self-encoded striping patterns were used as multiplexing assay substrates. A competitive assay format was developed to take advantage of stronger fluorescence output from DNA/DNA duplexes than that from DNA/miRNA duplexes. Upon selection of optimal competing DNA probes, the fluorescence signal collected was inversely proportional to the concentration of target miRNA in the system. A detection limit of fmol amounts of miRNA was achieved, with a linear response spanning across a broad dynamic range. The use of inherently encoded nanorods allowed simultaneous detection of different miRNA targets with good specificity.}, number={7}, journal={ANALYTICAL METHODS}, author={Zheng, Weiming and Chase, Thomas E. and He, Lin}, year={2014}, pages={2399–2405} }