Dissolution Behavior of Silicon Nitride Thin Films in a Simulated Ocular Environment

The time dependent dissolution of silicon nitride is studied in a simulated eye environment (controlled saline solution) as a function of temperature and pressure. Silicon nitride films manufactured by plasma-enhanced chemical vapor deposition (PECVD) and low-pressure chemical vapor deposition (LPCVD), respectively, were tested. The results revealed that both film types showed evidence of dissolution i.e., the films dissolved in the saline solution over time. At 37°C, PECVD and LPCVD silicon nitride membranes dissolved at a rate of 1.3 nm/day and 0.3 nm/day, respectively. It was found that at 23°C, the dissolution rate of the PECVD samples reduced to just 0.2 nm/day. Dissolution was not observed in samples tested in deionized water at 37°C. Titanium oxide layers (TiO2) were tested as protective layers to stop the dissolution. The results are important for implantable MEMS devices where silicon nitride is used as a functional membrane or as a protective layer.

Development of a Self-Parameter Tuning Based Adaptive Sliding Mode Observer for Input Fault Reconstruction of Longitudinal Autonomous Driving

This paper presents an adaptive sliding mode observer for input fault reconstruction of longitudinal autonomous driving. Sliding mode observer is the robust observer against disturbance, which is used to reconstruct the fault and state estimation. In order to design the injection parameter for sliding mode observer, the boundary of errors that include the fault is required. However, it is difficult to expect the fault magnitude for design the injection parameter. The proposed method is to estimate the proportional constant from the relationship between output error and injection parameter based on recursive least squares. Then, it is used to update the adaptive parameter based on MIT rule. The performance evaluation algorithm was conducted in Matlab/Simulink environment using actual longitudinal driving data and 3-dimensions vehicle model with the applied various faults.

Mass Production and Film Thickness Control of Meso Porous Silica Thin Films

Mesoporous silica (referred to as MPS), which has pores of hexagonal or cubic structure of several nm to several tens of nm on the surface, is attracting attention as a new material. MPS has a very large specific surface area, so it is used as an adsorbent for gas and water vapor, as a moisture absorbent, and as a separating material. Transparent MPS is also expected to be an optical functional material. MPS thin film is expected to be used as a thin film as an application example. Since MPS thin film can be used in various applications, it will be further developed by mass production. Leads to Therefore, in this study, mass production of MPS thin films and controlled the film thickness was studied. Roll-to-roll (referred to as R2R) production method and a micro gravure printing method was adopted as a method of mass production: transporting polypropylene film and coating on it. As a result, the MPS thin film prepared in this study had a pore structure. it was confirmed that the film thickness could be controlled by changing the peripheral speed ratio. It is considered that the size of the liquid pool between the coating rolls changed. The size and arrangement of the pores could be confirmed by FE-SEM observation.

Implementation of Reduce AI-NN Model for Highly Accurate Blood Pressure Measurement

This study proposes a reduce AI model for the accurate measurement of the blood pressure (BP). In this study varied temporal periods of photoplethysmography (PPG) waveforms is used as the features for the artificial neural networks to estimate blood pressure. A nonlinear Principal component analysis (PCA) method is used herein to remove the redundant features and determine a set of dominant features which is highly correlated to the Blood pressure (BP). The reduce features-set not only helps to minimize the size of the neural network but also improve the measurement accuracy of the systolic blood pressure (SBP) and diastolic blood pressure (DBP). The designed Neural Network has the 5-input layer, 2 hidden layers (32 nodes each) and 2 output nodes for SBP and DBP, respectively. The NN model is trained by the PPG data sets, acquired from the 96 subjects. The testing regression for the SBP and DBP estimation is obtained as 0.81. The resultant errors for the SBP and DBP measurement are 2.00±6.08 mmHg and 1.87±4.09 mmHg, respectively. According to the Advancement of Medical Instrumentation (AAMI) and British Hypertension Society (BHS) standard, the measured error of ±6.08 mmHg is less than 8 mmHg, which shows that the device performance is in grade “A”.

System Identification With Particle Swarm Optimization Method for Nonlinear Dynamic Systems

This paper presents a comparison between different system identification techniques, namely Least Squared Estimation, Total Least Squares, Linear Sequential Estimation, the Gauss-Newton method, and Particle Swarm Optimization. A DC motor model was simulated in Simulink, with arbitrarily selected parameters, and the input and output values were used to test the effectiveness of these system identification techniques.

Ranking of Thermal Asperity (TA) Interaction During Seeking Under Various Fly-Height Conditions

HDD heads have various interaction mechanisms with thermal asperities (TAs), and protection mechanisms need to be put in place to ensure the head-disk interaction (HDI) resulting from them is eliminated or minimized to the highest extent possible. It is straightforward to not allow the head sit-on-track on cylinders that have such TAs on them, and the same principle can be extended to so-called high TAs (HTAs), whose height is more than the fly height of the head, so heads do not inadvertently interact with the TA even when motion is triggered on another head, since the entire head stack moves together. Similar TA interactions also occur when the head seeks across the tracks. Typical short seeks have thermal fly-height control (TFC) turned on while it is turned on during long seeks, which is greater than a few hundred tracks. Heads can also interact with TAs during retract and arrival of the head during such long seeks. Finally, background media scan (BGMS), which is an industry standard, when the drive enters an idle state. Interaction with HTAs can also occur when the drive enters such a state. Typical seek avoidance attempts to eliminate TA interaction during seeking, however it is not straightforward to determine which of the seek mechanism: TFC On during short seeks, retract/arrival during long seeks, HTA interaction during long seeks with TFC off, or idle TA interaction causes the greatest HDI. Through theoretical analysis and experimental corroboration, this paper intends to rank the various modes of TA interaction, so by developing features for eliminating or minimizing them in that order could help bring the maximum benefit for achieving minimum lifetime reduction of the head due to such interaction.

A Method to Reduce Head-Disk Interface (HDI) Degradation Risk During Thermal Asperity (TA) Mapping in a Hard Disk Drive

One of the issues in thermal asperity (TA) detection using an embedded contact sensor (ECS) is the degradation caused to the read/write elements of the head while interacting with the TA. We propose a method to reduce such head-disk interaction (HDI) during TA detection and classification by flying higher at low thermal fly-height control (TFC) power, which minimizes the interaction of the TA with the head. The key idea is to scan the head at higher fly height, but with higher ECS bias voltage. Initial experiments have shown that the TA count follows a negative cubic relationship with the backoff at various bias levels, and that it follows a square relationship with bias at various backoff levels. Using a sample set, the calibration curves i.e. the golden relationship between these parameters can be established. Using these, one can start the TA detection at the highest backoff and high ECS bias, and start to estimate the nominal TA count. By mapping out these TAs and ensuring the head does not fly over them again to prevent HDI, the fly height can then be lowered, and the rest of the TA cluster can be scanned. Following this method iteratively, the entire TA cluster can be mapped out with minimal interaction with the head. Although this method entails an increase in the test time to detect and map all TAs, compared to detecting them with TFC being on, this can help improve the reliability of the drive by protecting the sensitive read/write elements especially for energy assisted recording from HDI.

Study of Contact Detect Response for PMR and HAMR Media Using the Integrated Thermistor Based Proximity Sensor

As the Hard Disk Drive industry migrates from PMR to HAMR technology, it is important to understand differences in the measurement of contact detection between PMR vs. HAMR media. Compared to PMR media, HAMR media tends to be rougher and has a higher thermal conductance. Since some contact detection methods rely on interface heat transfer, it is important to understand the impact of media type on measurements. In the current paper, we present results from mechanical spinstand studies using the integrated thermistor in the head. The heater in the head is dithered at a fixed frequency and the thermistor response is analyzed at that frequency. Changes in the thermistor resistance as a function of head-media clearance are used to understand how thermal conduction differences between PMR vs. HAMR media may impact contact detection. We find that heat conduction is different between HAMR and PMR media types and can have an impact on contact detection.

The Multi Wavelength Arrayed Flexible PPG Sensing Patch for to Estimate Heart Rate and Blood Oxygen

This study aims to develop the Photoplethysmography (PPG) sensor patch for to estimate the heart rate (HR) and blood oxygen (SpO2). A newly developed multi wavelength arrayed flexible OLED-OPD PPG sensing patch elevates the performance of motion artifact for not only for heart rate estimation but also blood oxygen estimation. The PPG sensing patch ensures the long-time continuous monitoring of the PPG signal from the wrist artery during sleeping, walking and cycling. The accuracy of the HRs is 92% and the accuracy of SpO2 is 95%.

A Switch Module Stacked With 4/3 IGBTs With Balanced Voltage Sharing for PEF Applications

Pulsed electric field (PEF) technology is a promising non-thermal pasteurization method that can be utilized to inactivate microorganisms in liquid food with high-voltage PEF. The power switch which is an important component of the PEF systems. This paper presents a design and implementation of an insulated gate bipolar transistor (IGBT) module which includes connections of three series and four parallel IGBTs and its special gate driver for small liquid food treatment systems at home. In this approach, two important issues must be considered. The first is to provide a safe operating condition for each single IGBTs in transient intervals. The second is to design gate drive systems with the capability of driving a large number of discrete devices simultaneously and ensure the current and voltage of single IGBTs in the module to be approximations. To evaluate the operation of the proposed structure, a module of three series and four parallel switches with the voltage capability of 1.8 kV and 60A is tested experimentally.