Characterization of biocompatible parylene-C coating for BioMEMS applications

This thesis characterizes parylene-C films with respect to biological micro-electro-mechanical system (BioMEMS) applications. BioMEMS devices have fueled the growth and research in the area of detecting, analyzing and identifying pathogens rapidly with precision in the bio-medical applications, thereby positively impacting millions of lives and made it extremely popular among researchers. These devices are fabricated using state-of-the-art techniques usually involving more than one material which typically has different biocompatibility and is not acceptable for various BioMEMS and biomedical applications; therefore, a special biocompatible coating is required. The parylene polymer is an example of such a coating as it is known for its biocompatibility (U.S. Pharmacopoeia (USP) Class VI) as well as possessing pinhole free surfaces with low penetrability which provide exceptional barriers to moistures and solvents. The vapor deposition process utilized for depositing parylene coating also provide conformable, uniform thickness throughout targeted sample even with high aspect ratio microstructures, and is compatible with both polymeric (e.g. PMMA, polycarbonate, etc.) and non-polymeric (e.g. nickel, silicon, etc.) substrates, as the samples are kept inside a room temperature (25° C) chamber where the final deposition step occurs. In this study, parylene coatings were characterized with respect to surface roughness, where roughness measurements show no significantly changes when parylene are deposited on “smoother” pristine PMMA (from ~Ra=2.66nm to ~Ra=2.85nm) and polycarbonate (from ~Ra=3.02nm to ~Ra=5.92nm) and reduces roughness of “rougher” surfaces (electroplated nickel from ~Ra=374nm to ~Ra=201nm). Parylene is also characterize with respect to surface energy by measuring contact angles, where pristine parylene surface (contact angle = ~89°) becomes more hydrophilic by treating it with oxygen plasma (contact angle = ~32°). Surface modification was used to control the number of live cells (HeLa) attaching on parylene, where O2 plasma was used to increase this by 2-folds and altering substrate roughness helped in minimizing the cells adhesion to parylene

Existence and regularity estimates for quasilinear equations with measure data: the case 1<p≤3n−22n−11<p\leq \frac{3n-2}{2n-1}

We obtain existence and global regularity estimates for gradients of solutions to quasilinear elliptic equations with measure data whose prototypes are of the form $-{\rm div} (|\nabla u|^{p-2} \nabla u)= \delta\, |\nabla u|^q +\mu$ in a bounded main \Om\subset\RR^n potentially with non-smooth boundary. Here either $\delta=0$ or $\delta=1$, $\mu$ is a finite signed Radon measure in $\Omega$, and $q$ is of linear or super-linear growth, i.e., $q\geq 1$. Our main concern is to extend earlier results to the strongly singular case $1<p\leq \frac{3n-2}{2n-1}$. In particular, in the case $\delta=1$ which corresponds to a Riccati type equation, we settle the question of solvability that has been raised for some time in the literature.Comment: 18 page

Utilizing CaCO3, CaF2, SiO2, and TiO2 phosphors as approaches to the improved color uniformity and lumen efficacy of WLEDs

The two elements that are most favorable in the quality evaluation for phosphor-converted LEDs (pcLEDs) these days are the chromatic homogeneity and the lumen output. In this study, a thorough research on enhancing color uniformity and luminous flux of pcLEDs that have a high correlated color temperature (CCT) of 8500K is carried out. The scattering enhancement particles (SEPs): CaCO3, CaF2, SiO2, and TiO2 are used to accomplish the goal by adding them to a yellow phosphor compounding Y3Al5O12:Ce3+, and comparing their characteristics afterwards. LightTools program is used to build an optical simulation and Mie-scattering theory helps to examine the achieved results. Specifically, the parameters included in SEPs’ scattering calculation are the scattering coefficients, the anisotropic scattering, the reduced scattering, and the scattering amplitudes at 455 nm and 595 nm. The outcomes presented that compared to other SEPs, TiO2 particles can yield the highest chromatic homogeneity. However, the lumen output reduces considerably as TiO2 concentration greatly increases while it can be bettered when using SiO2 particles with any particle size. For CaCO3 particles, the color deviation of 620 K CCT can be reduced with 30% concentration, leading to the recommendation of using CaCO3 to promote the CCT homogeneity and luminescence efficiency

Hardware Architectures of Visible Light Communication Transmitter and Receiver for Beacon-based Indoor Positioning Systems

High-speed applications of Visible Light Communications have been presented recently in which response times of photodiode-based VLC receivers are critical points. Typical VLC receiver routines, such as soft-decoding of run-length limited (RLL) codes and FEC codes was purely processed on embedded firmware, and potentially cause bottleneck at the receiver. To speed up the performance of receivers, ASIC-based VLC receiver could be the solution. Unfortunately, recent works on soft-decoding of RLL and FEC have shown that they are bulky and time-consuming computations. This causes hardware implementation of VLC receivers becomes heavy and unrealistic. In this paper, we introduce a compact Polar-code-based VLC receivers. in which flicker mitigation of the system can be guaranteed even without RLL codes. In particular, we utilized the centralized bit-probability distribution of a pre-scrambler and a Polar encoder to create a non-RLL flicker mitigation solution. At the receiver, a 3-bit soft-decision filter was implemented to analyze signals received from the VLC channel to extract log-likelihood ratio (LLR) values and feed them to the Polar decoder. Therefore, the proposed receiver could exploit the soft-decoding of the Polar decoder to improve the error-correction performance of the system. Due to the non-RLL characteristic, the receiver has a preeminent code-rate and a reduced complexity compared with RLL-based receivers. We present the proposed VLC receiver along with a novel very-large-scale integration (VLSI) architecture, and a synthesis of our design using FPGA/ASIC synthesis tools

A data-driven approach for Network Intrusion Detection and Monitoring based on Kernel Null Space

International audienceIn this study, we propose a new approach to determine intrusions of network in real-time based on statistical process control technique and kernel null space method. The training samples in a class are mapped to a single point using the Kernel Null Foley-Sammon Transform. The Novelty Score are computed from testing samples in order to determine the threshold for the real-time detection of anomaly. The efficiency of the proposed method is illustrated over the KDD99 data set. The experimental results show that our new method outperforms the OCSVM and the original Kernel Null Space method by 1.53% and 3.86% respectively in terms of accuracy

Genetic diversity of local rice varieties (Oryza sativa L.) in Vietnam’s Mekong Delta based on SSR markers and morphological characteristics

Based on target traits, use of the genetic diversity of rice is beneficial for crop improvement. In this study, 41 rice varieties local to Vietnam’s Mekong Delta were evaluated on the basis of 11 quantitative morphological traits, along with the assessment of genetic diversity according to 50 SSR markers. The actual yield had a significance level of 0.05, while plant height and panicles per square meter had a high significance level of 0.001. Cluster analysis based on 11 quantitative traits also revealed that two were the optimal number of clusters used in this study. The highest polymorphic information content (PIC) value obtained was for RM286 (0.49), with a range of 0.00 to 0.49 and an average PIC of 0.14. Both structure and phylogenetic tree analyses as inferred from 50 SSR markers by the unweighted pair‐group method with arithmetic mean (UPGMA) also indicated that the 41 local rice varieties could be divided into two major groups. This study provides a useful information for Mot bui do cao CM, and Mot bui five varieties for improvements in the yield and intermediate amylose content of local rice‐breeding programs in future, especially for the Mekong Delta region

The study of convex-dual-layer remote phosphor geometry in upgrading WLEDs color rendering index

The white-light light-emitting diode (LED) is a semiconductor light source that usually has one chip and one phosphor layer. Because of that simple structure, the color rendering index (CRI) is really poor. Therefore, structure with double layer of phosphor and multiple chips has been studied with the phosphorus proportions and densities in the silicone are constantly changed to find the best option to improve optical properties. In research, we use red phosphor Ca5B2SiO10:Eu3+ layer to place above the yellow phosphor one, and both of them have a convex design. Then, the experiments and measurements are carried out to figure out the effects of this red phosphor as well as the convex-double-layer remote phosphor design on the LED’s performances. The measured results reveal that the light output is enhanced significantly when using convex-dual-layer structure instead of the single-layer design. Additionally, the Ca5B2SiO10:Eu3+ concentration benefits CRI and CQS at around 6600 K and 7700 K correlated color temperature (CCT). Yet, the lumen output shows a slight decline as this red phosphor concentration surpass 26% wt. Through the experiments, it is found that a double layer of chip and double phosphorus is the best structure which could support the quality of CRI and luminous flux