Microsystem Technologies最新文献

These days, Wireless Sensor Networks (WSNs) have been broadly utilized in numerous areas such as battlefield surveillance, industrial process control, pipeline monitoring, defence and military affairs, and so forth. Various energy efficient works are conducted without addressing the secured data transmission process. It is very challenging task to transfer data efficiently and securely to the desired location. Various researches has been done in this field but there are few limitations like malicious nodes are not considered and very complex systems are used for authentication like encryption and key management. In this paper a secure energy efficient algorithm using improved LEACH in optimization with Fire Fly algorithm (FFA) and Artificial neural network (ANN) to overcome all above said issues has been proposed. Cluster head selection is done using a new threshold value taking into account residual energy, average energy and covering distance of the nodes as compared to existing LEACH which uses only a probability based random number for CH selection. Due to the presence of malicious nodes in the route network performance degrades and data drop rate increases so there is need of energy efficient along with secure routing protocol. To fulfil this requirement firefly algorithm is used to get optimized node properties as output then this data is passed to ANN to provide communicating and non-communicating nodes as a result and attacker node in the existing route. Based on this differentiation of nodes an optimized route is developed from source to destination by eliminating the malicious nodes from the route. Simulation results demonstrate that there is an improvement in various Qos parameters of network as compared to existing approaches.

Nephrometry scores play a critical role in the preoperative evaluation of partial nephrectomy. Although score comparisons have been performed for transperitoneal or open surgery, systematic comparisons for retroperitoneal operations are lacking. Authors have retrospectively evaluated the clinical records of patients who underwent partial nephrectomy at one center by one surgeon. Scores were generated according to the imaging results, and each score was categorized into low-, intermediate- and high-complexity groups. Then, the differences in perioperative outcomes were compared among the groups. We assessed whether the scores and sex, body mass index (BMI), age, or American Society of Anesthesiologists (ASA) Physical Status classification could predict whether the warm ischemia time (WIT) was likely be longer than 20 min and whether they could predict postoperative complications worse than Clavien–Dindo 1. The interobserver variability between two experienced surgeons for these scores was calculated with the intraclass correlation coefficient (ICC). Total of 107 patients were ultimately evaluated. The scores included in this study were significantly associated with the probability of having a WIT > 20 min and high-grade postoperative complications. Receiver Characteristic Operator (ROC) curves showed that there were no significant differences in their predictive power. NePhRo had the highest agreement (0.839), followed by DAP (0.827). RENAL was superior to SPARE and PADUA, which were 0.758, 0.724 and 0.667, respectively.

This paper aims to demonstrate the effect of employing the mechanical and electrical governing systems of the hydro unit on the load frequency control (LFC) of an interconnected hydrothermal power system (IHTPS). The IHTPS has the thermal unit in area 1 and the hydro unit in area 2, and the performance is analyzed for injecting 10% step load disturbance (SLD) in both areas. The investigation is performed under the tilt-integral-double derivative filter (TIDDF) controller optimized with the crow search optimization algorithm (CSOA). However, the competency of the proposed control strategy is evinced by testing on the widely accepted model of a two-area thermal system (TATS), and it is revealed that the suggested control technique outperforms the other control strategies reported in the literature. Later, the analysis on IHTPS is performed by considering the hydro unit with the mechanical governing system, which is later extended to the consideration of the electrical governing system under the same disturbance loadings. Simulation results reveal the significance of employing an electrical governing system with the hydro unit for better frequency regulation of IHTPS over the mechanical one as it has the limited response rate. Furthermore, the investigations on IHTPS extend to the incorporation of the HVDC line to obtain an improvement in dynamic performance.

The work reported here focuses on improving the electrical conductivity of tungsten disulfide (WS₂) nanosheets by n-type impurity doping. The WS₂ is a 2D transition metal dichalcogenide material which possess desirable properties such as high mobility and bandgaps, making them potential candidates for future semiconductor device applications. However, the presence of sulfur vacancies in semiconductor and weak binding energy at the metal–semiconductor interface often results in a high Schottky barrier height (SBH) leading to poor electrical conductivity. To overcome this issue, the research focusses on investigating the reduction of SBH at the junction between WS₂ and metal. The effect of time dependent chlorine (Cl) doping on the SBH of exfoliated WS₂ was studied through I–V measurement at different temperatures. The results indicate SBH reduction from 0.75 eV for undoped to 0.65 eV for Cl doped samples. Overall, the study demonstrates that Cl doping can effectively decrease the Schottky barrier height of WS₂ thin-film, leading to enhanced electrical transport properties. The mechanism involved in the modulation of electronic property of the system is also explained with the help of an energy band model. These findings contribute to the understanding and advancement of high-performance semiconductor devices established on the n-type doping of WS₂ thin film.

In this work, a nano-plasmonic device based on Aluminum with BiFeO₃ (BFO), as a multiferroic oxide with remarkable dielectric properties, is engineered using the transfer matrix method for implementation in an optical communication band for sensing applications. A comparative study is performed between different dielectric materials (e.g., BFO, Silicon, and Indium Phosphide), and the highest Figure of Merit (FOM) is achieved for the surface plasmon resonance sensor with BFO as the intermediate layer. To further increase the binding efficiency of the biomolecules with the sensing surface, a monolayer of 2D nanomaterial, namely Molybdenum disulfide, Graphene, MXene, and Fluorinated Graphene (FG), is added to the surface of the plasmonic device. After a rigorous analysis, FG is found to have the highest FOM of 334°/RIU and sensitivity of 125°/RIU. In summary, our work reveals potential applications for the proposed nano-plasmonic device based on Al-BFO configuration as a new type of supporting material with a monolayer of FG for enhancing biosensing activity.

With considerably small structure and ultrahigh sensitivity, the graphene resonant gyroscope has been widely used in aviation, aerospace and deep-sea exploration where sensing the extremely weak angular velocity changes is required. However, small difference in the size of graphene resonant gyroscope caused by inherent uncertainties in various processing and material parameters will lead to huge differences in the output results. This will reduce the reliability of graphene resonant gyroscope. Based on the above issues, the uncertainty analysis method is adopted to establish a numerical model on the direct output resonant frequency and sensitivity of the graphene resonant gyroscope, and a random model based on sampling is introduced. The influence of the uncertainty of six input parameters on the graphene resonant frequency and sensitivity output is clarified, and thus the effect degree of the main parameters, which play a key role in the performance of the graphene resonant gyroscope, is obtained. The results show that the length, width and thickness of the graphene resonant beam have greater impacts on the output parameters, which provides theoretical guidance for the graphene resonant gyroscope to adapt to different measurement ranges.

A gravity compensation (GC) device compensates for the torque originating from a constant mass or payload, which occupies a large part of the capacity and energy consumption of an actuator on the joint. Adapting a GC device can reduce energy consumption and capacity of the actuator. A GC device comprises an energy-storage component and a motion-converting mechanism. The energy storage component stores and releases energy according to the change in gravitational energy as the mass of the joint rotates. The motion-converting mechanism matches the energy from the energy storage component to the gravitational energy of the rotating mass. The majority of GC devices use springs as the energy storage component, and they are connected to the body by motion-converting mechanisms, such as gears and slide cranks. A GC device that uses magnetic energy as an energy storage component was proposed in this study. It uses noncontact permanent magnets (PMs) as energy storage components. It is designed to have a simple structure and compact size, and can be easily connected to the actuator module, similar to commercial gear reducers. It comprises two identical structures, consisting of one yoke and two PMs. The two structures are assembled as the PMs face each other and generate attractive and repulsive forces depending on the relative angle between the two facing PMs. The shapes of the PMs were determined to generate a sinusoidal torque profile to compensate for the gravitational torque by a mass. The designed mechanism is verified through simulations and experiments.

We designed a MEMS microvalve based on the nanoscopic electrostatic drive (NED) technology (Nat Commun 6:10078, 2015). NED actuators, electrostatically controlled bending beams, are implemented in a clamped-clamped configuration. A normally open plunger valve was designed and characterized. The device is manufactured from silicon. Gas flow rates of up to 37 SCCM can be proportionally controlled between 10% and 100%. A 10% leakage is always present at low backpressures (< 10 kPa) and increases to roughly 20% at 75 kPa backpressure. The structure has been tested up to backpressures of 300 kPa without damage to the structures, but the leakage increases to over 95%. Our unprecedented microvalve concept shows that it is possible to manufacture all-silicon MEMS microvalves with proportional control of the flow rate. The presented work is a proof of concept to test the capabilities of the NED technology for the use in microvalves. There are plans to decrease the leakage in future designs by introducing an additional sealing layer as well as manufacturing a shutter instead of a plunger design.

Nanosphere structures using noble metals are suitable and efficient for the development of biosensors for the detection of analytes in biological applications based on refractive index-based sensing. The nanosphere structure acts as a surface plasmon device. The gold nanospheres are commonly used as nanodevices. The modeling and analysis of the gold nanosphere structure are carried out in this work. The Mie-scattering algorithm is used to find the extinction efficiency, scattering efficiency, and absorbance efficiency of gold nanospheres, while dipole approximation methods are used as sources in the modeling of gold nanospheres with effective radii. The cross-section efficiency and sensitivity of the nanosphere-based refractive index sensor are analyzed. The mathematical analysis is conducted using the discrete dipole approximation method. The Riccati–Bessel functions are used in the Mie calculations.

This research article presents a simulation study on a dielectric pocket engineered dual metal nanowire ferroelectric (DPE-DM-NW-Fe FET) MOSFET. The aim is to mitigate the Gate-Induced Drain Leakage (GIDL) effect in the off-state condition and improve the subthreshold swing. GIDL is a type of SCE which is detrimental for the device as continuous gate leakage current. Severely hamper the performance of the device particularly in analog applications. To prevent this a novel structure is proposed in which two dielectric pockets are introduced adjacent to the source and drain to reduce the SCEs. GIDL occurs even when the gate voltage is nearly zero, but it becomes significant when the gate region is at a lower bias and the drain region is at a higher bias. The introduced dielectric pockets act as diffusion stoppers, forming insulating barriers to prevent off-state current. Simulation studies were conducted to analyze off-state GIDL currents for different channel lengths (30 nm, 40 nm, and 50 nm). Various parameters such as electric field, electron concentration, electron velocity, and surface potential have been simulated and compared with a Single Metal Gate (SMG) cylindrical MOSFET. Critical performance parameters including drain current, transconductance (g_m), output conductance (g_d), input capacitance (C_GG), cutoff frequency (f_T), gain transconductance frequency product (GTFP), gain frequency product (GFP), maximum transfer power gain (MTPG), unilateral power gain (UPG), and early voltage (V_ea) have been calculated. Additionally, the noise performances of the DPE-DM-NW-Fe FET have been examined, and its implementation as a CMOS inverter have been explored for determining noise margins. The lower noise margin makes the device suitable for high-frequency applications. The simulations have been conducted using the ATLAS-3D simulator.