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Neuron-on-chip (NoC) systems—microfluidic devices in which neurons are cultured—have become a promising alternative to replace or minimize the use of animal models and have greatly facilitated in vitro research. Here, we review and discuss current developments in neuron-on-chip platforms, with a particular emphasis on existing biological models, culturing techniques, biomaterials, and topologies. We also discuss how the architecture, flow, and gradients affect neuronal growth, differentiation, and development. Finally, we discuss some of the most recent applications of NoCs in fundamental research (i.e., studies on the effects of electrical, mechanical/topological, or chemical stimuli) and in disease modeling. [ABSTRACT FROM AUTHOR]

This paper studies energy and time optimality of electric vehicles during constant Ackerman steering along a quad-circle, and proposes an autopilot assimilating the optimal results. The energy and time optimal solutions satisfying the steering and battery limitations are generated and a Pareto-front analysis is carried out with multi-objective optimization using NSGA-II algorithm. In the autopilot design, the indicators for the energy and time optimality performances are merged in a vehicle status vector. At each control cycle of the optimal drives, the torque commands and the vehicle status vectors are stored and later clustered using the k-means algorithm. At each cluster centre, a pair of the vehicle status vector and the control command vector is acquired and these pairs designate the rules that generate the unique optimal control command associated with a particular vehicle status. A convex combination of these rules constitutes the autopilot design. The proposed autopilot is tested against the energy-time Pareto-front extracted, and it is observed that in terms of the performance measures, the optimality has been preserved. Additionally, for various weightings of time and energy optimality objectives, the performance of the autopilot is compared with that of optimal controllers with weighted objectives. The results verify the quality of the autopilot design using a decision-making process over a rule set inferred from the solutions acquired with optimal solutions. [ABSTRACT FROM AUTHOR]

In this work, characteristics of trench sidewall capacitance were investigated in a 4H-SiC stepped thick-oxide (STO) trench metal–oxide–semiconductor (MOS) structure. Multigroup SiC trench MOS capacitor test patterns with different structures and geometric parameters were designed and fabricated. From the capacitance–voltage measurements, the characteristics of the described SiC STO trench MOS were calculated and analyzed, including the thicknesses of the oxide at different locations in trench, the position of the oxide step at trench sidewall, and the flat-band voltages as well as the oxide charge densities of MOS from the upper part and lower part of oxide step at trench sidewall. Results showed that the flat-band voltages of MOS from the upper part (10.2 V) and lower part (12.5 V) of trench sidewall step had pronounced positive shifts over the ideal flat-band voltage (0.36 V), indicating a massive negative charges in the sidewall oxide film. Meanwhile, the net oxide charge density of MOS from the lower part of sidewall step ($- 0.92\times10$ 12 cm $^{-2}$) was smaller than that from the upper part ($- 2.41\times10$ 12 cm $^{-2}$), which was likely attributed to the massive shallow states in the oxide and to the poor quality of the thick-oxide film grown via chemical vapor deposition technology. The present works are providing a convenient technology to monitor the trench MOS structure by measuring the capacitance during SiC trench MOSFETs fabrication. [ABSTRACT FROM AUTHOR]

This article presents a new uncompensated analog pulsewidth modulation (PWM) pixel circuit employing pull-up control for micro-light-emitting diode (LED) display. The time of emitting light for the micro-LED working at the constant current is modulated by the analog data voltage. A compensated pixel circuit is also further developed to improve the display uniformity by compensating the threshold voltage shift of PWM thin-film transistor (TFT) and driving TFT. Based on the back-channel etch (BCE) metal oxide TFTs process, $16\times $ GGG $\times29$ LED array with the uncompensated pixel circuit and 16 $\times {G}\,\,\times15$ LED array with the compensated pixel circuit are simultaneously fabricated on the same glass substrate. Compared with the uncompensated pixel circuit array, the display uniformity of the compensated pixel circuit array is improved from 74% to 88%. [ABSTRACT FROM AUTHOR]

The multiple fluctuations, such as grid DC input voltage, mutual inductance and the plug-in and plug-out of battery, may lead to instability and deterioration of dynamic performance of electric vehicle (EV) wireless power transfer (WPT) system. The overshoot issue can bring great current stress to EV WPT system, and may induce potential disastrous malfunction of the lithium-ion (Li-ion) battery. This study theoretically reveals the slow dynamic response and large overshoot of a traditional WPT system. For solving these issues, a reliable adaptive feedforward control scheme is proposed and applied in the user-side DC-DC converter, where the communication unit is eliminated. The feedforward loop is proved theoretically to suppress overshoot and system dynamic response. Besides, the feedforward control increases the selective range of control parameters, which can improve the system dynamics. Experiment results verifies that the proposed adaptive feedforward gain allows faster dynamics, and the aforementioned disturbances in EV WPT system can be solved while the system performance is not affected. [ABSTRACT FROM AUTHOR]

A 6.78-MHz multiple-transmitter (TX) wireless power transfer (WPT) system was presented. An adaptive magnetic field adder (AMFA) IC was proposed, for the first time, to enable the maximization of the system efficiency ($\eta _{\mathrm {SYS}}$) by adaptively optimizing the amplitude and phase of the current in each TX coil on the basis of the coupling coefficient ($k$) between each TX coil and the receiver (RX) coil. Under the optimal condition, the current in each TX coil is proportional to $k$ between the TX coil and the RX coil. For the independent control of the current in each TX coil, a selectively activated shared-half-bridge (HB) power amplifier (PA) together with an alternate TX coil array was proposed. To sense a small $k$ , duty-ratio control was proposed in the integrated $k$ sensor. The AMFA IC was fabricated by a 0.18- $\mu \text{m}$ CMOS process with 1.8-V devices. The peak power conversion efficiency of the proposed PA reached 74%. The $k$ sensor could accurately measure $k$ with a percentage error within ±2.5%. A WPT system consisting of a $4\times 4$ TX coil array driven by four AMFA ICs and a single RX coil was implemented. Experimental results showed that, compared with the conventional system, $\eta _{\mathrm {SYS}}$ was increased from 0.11% to 51% with a load power of 576 mW when the RX coil was perpendicular to the TX coils. When the RX coil was parallel to the TX coils, a $\eta _{\mathrm {SYS}}$ of 63%, which is higher than those in previous works, was also achieved. [ABSTRACT FROM AUTHOR]

Objective: We propose a tactile-induced-oscillation approach to reduce the calibration time in somatosensory brain-computer interfaces (BCI). Methods: Based on the similarity between tactile induced event-related desynchronization (ERD) and imagined sensation induced ERD activation, we extensively evaluated BCI performance when using a conventional and a novel calibration strategy. In the conventional calibration, the tactile imagined data was used, while in the sensory calibration model sensory stimulation data was used. Subjects were required to sense the tactile stimulus when real tactile was applied to the left or right wrist and were required to perform imagined sensation tasks in the somatosensory BCI paradigm. Results: The sensory calibration led to a significantly better performance than the conventional calibration when tested on the same imagined sensation dataset ($\text{F}_{(1,19)}$ =10.89, P=0.0038), with an average 5.1% improvement in accuracy. Moreover, the sensory calibration was 39.3% faster in reaching a performance level of above 70% accuracy. Conclusion: The proposed approach of using tactile ERD from the sensory cortex provides an effective way of reducing the calibration time in a somatosensory BCI system. Significance: The tactile stimulation would be specifically useful before BCI usage, avoiding excessive fatigue when the mental task is difficult to perform. The tactile ERD approach may find BCI applications for patients or users with preserved afferent pathways. [ABSTRACT FROM AUTHOR]

Motor developmental delay (MDD) usually affects the inter-joint coordination for limb movement. However, the mechanism between the abnormal inter-joint coordination and MDD is still unclear, which poses a challenge for clinical diagnosis and motor rehabilitation of MDD in infant’s early life. This study aimed to explore whether the joint activities of limbs during infant crawling are represented with kinematic synergies of joint angles, and evaluate the impacts of MDD on the inter-joint coordination using those synergies. 20 typically developing infants, 16 infants at risk of developmental delay, 11 infants at high risk of developmental delay and 13 infants with confirmed developmental delay were recruited for self-paced crawling on hands and knees. A motion capture system was employed to trace infants’ limbs in space, and angles of shoulder, elbow, hip and knee over time were computed. Kinematic synergies were derived from joint angles using principal component analysis. Sample entropy and Spearman’s rank correlation coefficients were calculated among those synergies to evaluate the crawling complexity and the symmetry of bilateral limbs, respectively. We found that the first two synergies with different contributions to the crawling movements sufficiently represented the joint angular profiles of limbs. MDD further delayed the development of motor function for lower limbs and mainly increased the crawling complexity of joint flexion/extension to some extent, but did not obviously change the symmetry of bilateral limbs. These results suggest that the time-varying kinematic synergy of joint angles is a potential index for objectively evaluating the abnormal inter-joint coordination affected by MDD. [ABSTRACT FROM AUTHOR]

Compared with normal color vision observers (NOs), anomalous trichromats (AT) have anomalous color vision responses owing to differences in cone sensitivity. The wide-color-gamut display provides a promising solution to this problem. Herein, we propose a color discrimination experiment based on a wide-color-gamut display. The observers’ abilities to discern colors in various color directions were tested. The experimental findings were confirmed by simulations based on the shifting of the photopigments spectral absorption. It is concluded that the wide-color-gamut display significantly improves the color perception ability of AT, while proper light source optimization significantly enhances the visualization of AT. The study findings show that this AT-based, color vision model, may open up opportunities for future visual perception and biomedical applications. [ABSTRACT FROM AUTHOR]

There has been renewed interest in coherent detection to provide high spectral efficiency transmission for short-reach optical interconnects. However, the expensive high-stable laser sources may preclude its potential application. To balance the high performance and low cost for short-reach optical networks, the self-coherent homodyne receiver has been investigated, where the dual-polarization (DP) signal and the remote local oscillator (LO) originating from the same laser source co-propagate over a duplex fiber, enabling a remarkable tolerance of laser linewidth. However, the fast evolution of the state of polarization (SOP) of remotely delivered LO becomes problematic for self-coherent homodyne detection systems. To combat the polarization wandering of the remote LO, the complicated adaptive/automatic polarization controller (APC) has been deployed with only up to a few hundred rad/s polarization tracking speed. In this paper, we propose a complementary polarization-diversity coherent receiver (C-PDCR) for self-coherent homodyne detection using remote LO. The proposed C-PDCR features rapid polarization tracking for remote LO utilizing electronic digital signal processing (DSP). The robustness of the proposed C-PDCR is verified and demonstrated with a 1.08-Tb/s line rate (net rate 769.4 Gb/s over 45-GHz electrical bandwidth) using DP PCS-256QAM signal under rapid polarization rotation rate up to 314 krad/s in the experiment, which is more than 3-orders improvement of magnitude compared to the prior reports. [ABSTRACT FROM AUTHOR]

This letter reports the demonstration of 1.2 kV 4H-SiC Schottky-integrated MOSFETs (JBSFETs) achieving the same specific on-resistance as the pure MOSFET by using an innovative layout approach as well as novel deep P-well structure. The proposed JBSFET significantly reduces the specific on-resistance accomplishing 2x reduction in the chip size, when compared with the traditional, chip-to-chip parallel connection of separate MOSFET and JBS diode. Moreover, the leakage current originated from the Schottky contact was successfully suppressed by adopting a $1.8~\mu \text{m}$ deep P-well structure implemented by channeling implantation. Device design strategy with layout approach, fabrication, and static and short-circuit characteristics are discussed in this letter. In order to understand and clarify the experimental results, 2D simulations were conducted. [ABSTRACT FROM AUTHOR]

This paper concerns the detection and identification of errors in the parameters of three-phase transposed as well as untransposed transmission line (TL) models used by various network applications. Such detailed models are increasingly needed in particular by power system applications where loads may not be balanced and/or TLs may not be symmetrical, and a full detailed three-phase solution may have to be obtained. To address this problem, the paper proposes an efficient algorithm for detection, identification, and estimation of parameter errors using synchronized phasor measurements. The suspect TL is detected using the modal domain networks in the first stage. The developed algorithm extends the previously developed largest normalized Lagrange multiplier (NLM) test for positive sequence parameters to the full coupled three-phase lines. An estimation method is also proposed for estimating the erroneous parameters, which takes into account the correlation of the parameters. To illustrate the effectiveness of the method, several tests are performed on the IEEE 118-bus system and a large 3474-bus utility system. [ABSTRACT FROM AUTHOR]

Double silicon-on-insulator (DSOI) technology featuring two buried oxide layers under silicon film has drawn excessive attention to space applications by modulating the electric field in back channel. This article studied the impact of the total ionizing dose (TID) effect on the n-channel metal oxide semiconductor field effect transistors (nMOSFETs) based on DSOI materials. Radiation-induced degradation in performance only appeared in the metal oxide semiconductor field effect transistor (MOSFET) with $W/L = 0.15~\mu \text{m}$ /10 $\mu \text{m}$ after 1.5 Mrad(Si) irradiation and recovered with negative $V_{\mathrm {bg}}$ applied. However, due to the weak coupling effect between the front and back gates, the threshold voltage ($V_{\mathrm {th}}$) of nMOSFET with $W/L = 10~\mu \text{m}$ /10 $\mu \text{m}$ and $10~\mu \text{m}/0.13~\mu \text{m}$ declined 0.06 V compared with devices before irradiation when $V_{\mathrm {bg}}$ is set to 0 V. The TCAD simulation and testing results reveal that the electric field introduced by negative back-gate bias could effectively mitigate the TID-induced performance degradation in DSOI nMOSFETs. The investigation will facilitate the application of DSOI technology for high-radiation-dose conditions. [ABSTRACT FROM AUTHOR]

Vector processors (e.g., SIMD or GPUs) are ubiquitous in high performance systems. All the supercomputers in the world exploit data-level parallelism (DLP), for example by using single instructions to operate over several data elements. Improving vector processing is therefore key for exascale computing. However, despite its potential, vector code generation and execution have significant challenges. Among these challenges, control flow divergence is one of the main performance limiting factors. Most modern vector instruction sets, including SIMD, rely on predication to support divergence control. Nevertheless, the performance and energy consumption in predicated codes is usually insensitive to the number of active elements in a predicated mask. Since the trend is that vector register size increases, the energy efficiency of exascale computing systems will become sub-optimal. This article proposes a novel approach to improve execution efficiency in predicated vector codes, the Compiler-Assisted Compaction/Restoration (CACR) technique. Baseline CR delays predicated SIMD instructions with inactive elements, compacting active elements from instances of the same instruction of consecutive loop iterations. Compacted elements form an equivalent dense vector instruction. After executing the dense instructions, their results are restored to the original instructions. However, CR has a significant performance and energy penalty when it fails to find active elements, either due to lack of resources when unrolling or because of inter-loop dependencies. In CACR, the compiler analyzes the code looking for key information required to configure CR. Then, it passes this information to the processor via new instructions inserted in the code. This prevents CR from waiting for active elements on scenarios when it would fail to form dense instructions. Simulated results (gem5) show that CACR improves performance by up to 29 percent and reduces dynamic energy by up to 24.2 percent on average, for a a set of applications with predicated execution. The baseline CR only achieves 18.6 percent performance and 14 percent energy improvements for the same configuration and applications. [ABSTRACT FROM AUTHOR]

Recently, CMOS invertible logic has been presented and is one of the new computing paradigms based on a probabilistic device model. It is designed based on stochastic computing that provides bidirectional operations between inputs and outputs and has been applied for several critical issues, such as integer factorization and machine learning (ML). This article presents an overview of CMOS invertible logic from principle to application. First, the principle is explained with a simple design example, and a design flow is introduced, as is an automatic design tool. Second, the hardware of CMOS invertible logic is designed using stochastic computing and then evaluated in two applications implemented on a field-programmable gate array (FPGA) or application-specific integrated circuits (ASICs). Finally, this article ends with future challenges. [ABSTRACT FROM AUTHOR]

Adult hippocampal neural stem/progenitor cells (AHPCs), which are self-renewing multipotent progenitors that can differentiate into neurons, astrocytes, and oligodendrocytes, are suitable as a central nervous system (CNS) molecular model, and the formation of 3D AHPC neurospheroids are potentially suitable as an in vitro brain model. In this paper we report a new microfluidic chip to culture AHPC neurospheroids (NSs-AHPC) inside culture-chambers on chip. After cell fixation and immunostaining were conducted, the fluorescence images of NSs-AHPC were analyzed. It has been found that the AHPCs comprising neurospheroids remained highly viable. Cell proliferation and neuronal differentiation have also been observed, indicating the feasibility of NSs-AHPC as the in vitro brain model on chip. Given its simple-to-use, low-cost, and orderly arranged culture-chambers, this type of chip is particularly suitable for culturing and analyzing multiple in vitro brain models in an efficient manner. [2021-0199] [ABSTRACT FROM AUTHOR]

Presents the table of contents for this issue of this publication. [ABSTRACT FROM AUTHOR]

This study solves the magnetic energy minimization problem in inductive power-transfer systems to suppress the magnetic field intensity and formulate the lowest boundary of the magnetic energy. The theoretical analysis shows that the minimum value of the magnetic energy is a function only of the coupling coefficient, quality factor of a receiver, and transmitting power and it converges to 0 under the condition that the coils and their coupling are ideal. The electromagnetic simulations verify the suppression effects of the magnetic field intensity by magnetic energy minimization and show quite a small loss in the transfer efficiency. [ABSTRACT FROM AUTHOR]

A special vibration mode called intrinsic localized mode (ILM) in a dispersed multi mass point-nonlinear spring system has been actively studied in solid-state physics and has a high application potential in engineering. Previous studies have only considered parameter-invariant systems; hence, active control of the excited ILM is not possible. Therefore, even though the phenomena are very interesting, there are no applications to devices. In this article, we propose a new paradigm of ILM by designing a dynamic nonlinear vibration system that can treat nonlinear spring properties in a variable manner depending on the applied current. By using variable spring characteristics, the localized vibration energy of the ILM can be freely transferred in unconventional way than before. The spring properties of the variable spring structure with applied current are investigated using finite element analysis. Then, numerical simulations in MATLAB show that the active control of the ILM is possible in a dynamic vibration system with variable spring characteristics. [ABSTRACT FROM AUTHOR]

A soliton is a unique wave that maintains its shape and constant velocity. It has been observed widely in natural nonlinear systems. In particular, a magnetic soliton has been observed experimentally on a nonlinear LC ladder circuit array. The aim of this article is to excite a magnetic soliton on the LC ladder circuit array using a permanent-magnet-flux-biased (PMFB) inductor. Electromagnetic analysis reveals that the PMFB inductor has exponential inductance characteristics due to the effective use of magnetic saturation in the stator core. Four PMFB inductors with different magnetic circuit topologies are analyzed and compared, to decrease the inductor current. Finally, this article numerically solves the loop equation for the LC ladder circuit array and shows that the magnetic soliton is successfully excited and propagates without changing its shape and velocity. This technique is equivalent to a rotating magnetic field and has a great potential in developing new ac motors or actuators. [ABSTRACT FROM AUTHOR]

This article presents a new hybrid dynamic vibration absorber (DVA) using the Coriolis effect to reduce a rotational vibration observed in various kinds of rotating machinery. The Coriolis force is generated by a linear oscillatory actuator (LOA), which reciprocates in the radial direction. The effectiveness of the proposed hybrid DVA is confirmed through a MATLAB/Simulink simulation under passive and hybrid operations of the LOA. Moreover, an active torque ripple control is also presented for the purpose of applying this DVA to a switched reluctance motor (SRM). A numerical simulation shows that the proposed hybrid DVA is able to reduce the torque ripple of the SRM by a nonsinusoidal position control of the LOA. [ABSTRACT FROM AUTHOR]

A stacked-coil technology is demonstrated that realizes size-adjustable coil systems to compensate the notorious problem of lateral misalignment in nonradiative wireless power transfer (WPT) systems. The proposed system has a simple structure that consists of multiple layers of coils with various sizes. Depending on the misalignment, the coil pair that provides the best transfer efficiency is switched on. Thus, not only the transfer null is removed, but also a very high transfer efficiency is maintained even with extreme misalignment. Experimental results at 6.78 MHz show the effectiveness of the stacked coil for both short- and mid-range wireless power transfer systems. The transfer efficiency maintains abovementioned 80% up to 87% and 65% lateral misalignment when the separation between Tx and Rx coils are 10% and 50%, respectively, relative to the largest dimension of the coil. The three-layer short-range system successfully removes the transfer null to maintain a minimum transfer efficiency of 39.7% up to 126% misalignment. The two-layer mid-range system maintains transfer efficiency abovementioned 50% up to 103% misalignment. Furthermore, the performance is virtually the same even in an asymmetric WPT system, i.e., when the technique is applied to only one of the two coils. A detailed design procedure is also provided. [ABSTRACT FROM AUTHOR]