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Carbon nanotubes (CNTs), owing to their superior electrical and mechanical properties, are a promising alternative to nonmetallic electrically conducting materials. In practice, cellulose as a low‐cost sustainable matrix has been used to prepare the aqueous dispersion of cellulose‐CNT (C‐CNT) nanocomposites. However, the compatibility with conventional solution‐processing and structural rearrangement for improving conductivity has yet to be determined. Herein, a straightforward route to prepare a conductive composite material from single‐walled CNTs (SWCNTs) and natural pulp is reported. High‐power shaking realizes the self‐alignment of individual SWCNTs in a cellulose matrix, resulting from the structural change in molecular orientations owing to countless collisions of zirconia beads in the aqueous mixture. The structural analysis of the dried C‐CNT films confirms that the entanglement and dispersion of C‐CNT nanowires determine the mechanical and electrical properties. Moreover, the rheological behavior of C‐CNT inks explains their coating and printing characteristics. By controlling shaking time, the electrical conductivity of the C‐CNT films with only 9 wt.% of SWCNTs from 0.9 to 102.4 S cm−1 are adjusted. the optimized C‐CNT ink is highly compatible with the conventional coating and printing processes on diverse substrates, thus finding potential applications in eco‐friendly, highly flexible, and stretchable electrodes is also demonstrated. [ABSTRACT FROM AUTHOR]

The dielectrophoretic (DEP) force acting on micro- and nanoparticles is highly dependent on the gradient of the electric field experienced by the particles. The DEP force enables the selective capture and removal of micro- or nanoscale particles from the fluid flow within the microchannels. Designing the geometrical structure of electrodes to increase the electric-field gradient within a 3D microfluidic channel is important in particle classification and alignment applications. In this study, we evaluated the particle alignment performance of wave-shaped electrodes, a modified geometrical form of conventionally used interdigitated electrodes, by calculating the DEP force experienced by particles within a microfluidic channel and analyzing the force in both the in-plane (xy) and out-of-plane (xz) directions. The particle alignment efficiency of both electrode forms was evaluated using finite element analysis and nanowire alignment experiments in an actual microfluidic channel environment. [ABSTRACT FROM AUTHOR]

In integrated circuits (ICs), the parasitic capacitance is one of the crucial factors that degrade the circuit dynamic performance; for instance, it reduces the operating frequency of the circuit. Eliminating the parasitic capacitance in organic transistors is notoriously challenging due to the inherent tradeoff between manufacturing costs and interlayer alignment accuracy. Here, we overcome such a limitation using a cost‐effective method for fabricating organic thin‐film transistors and rectifying diodes without redundant electrode overlaps. This is achieved by placing all electrodes horizontally and introducing sub‐100 nm gaps for separation. A representative small‐scale IC consisting of five‐stage ring oscillators based on the obtained nonparasitic transistors and diodes is fabricated on flexible substrates, which performs reliably at a low driving voltage of 1 V. Notably, the oscillator exhibits signal propagation delays of 5.8 μs per stage at a supply voltage of 20 V when utilizing pentacene as the active layer. Since parasitic capacitance has been a common challenge for all types of thin‐film transistors, our approach may pave the way toward the realization of flexible and large‐area ICs based on other emerging and highly performing semiconductors. [ABSTRACT FROM AUTHOR]

Transport and alignment of microscopic chips are important steps in microelectronics component integration with common approaches being pick‐and‐place, microfluidics, parallel transfer and self‐assembly. An alternate transport approach of microscopic chips is proposed using patterned liquid micro rails as chaperones. The surface free energy and interfacial free energy minimization of all constituents enable the creation of stable pathways. This allows for chip‐attachment to rails, while the liquid layer lubricates chip‐sliding. Monorails, digital monorails, and digital birails are investigated for chip movement behavior. Chip position and speed can be controlled using liquid flow in closed chambers. Speeds from 10 to 400 mm s−1 are achieved with translation distances as long as 50 mm. It is discovered that chips can selectively cross rail discontinuities of up to 500 µm, allowing for chip position control through a stop‐and‐go motion. A programmable liquid rails‐based chip conveyor system is demonstrated by transporting diodes to receptor sites where they undergo self‐assembly. [ABSTRACT FROM AUTHOR]

Dielectrophoresis is a potential candidate for aligning nanorods on electrodes, in which the interplay between electric fields and microfluidics is critically associated with its yield. Despite much of previous work on dielectrophoresis, the impact of frequency modulation on dielectrophoresis-driven nanorod self-assembly is insufficiently understood. In this work, we systematically explore the frequency dependence of the self-alignment of silicon nanorod using a microfluidic channel. We vary the frequency from 1kHz to 1000 kHz and analyze the resulting alignments in conjunction with numerical analysis. Our experiment reveals an optimal alignment yield at approximately 100 kHz, followed by a decrease in alignment efficiency. The nanorod self-alignments are influenced by multiple consequences, including the trapping effect, induced electrical double layer, electrohydrodynamic flow, and particle detachment. This study provides insights into the impact of frequency modulation of electric fields on the alignment of silicon nanorods using dielectrophoresis, broadening its use in various future nanotechnology applications. [ABSTRACT FROM AUTHOR]

Robot-assisted rehabilitation is a rapidly advancing field whereby robotic devices are used for the treatment of disabilities. Mechanism design and actuation of these devices play important roles in the treatment and the non-ergonomic designs may even increase the cardiorespiratory load and cause discomfort leading to further gait disorders. This article identifies crucial design and actuation aspects of gait rehabilitation robots and presents the first intrinsically compliant gait robot design with three actuated and five passive degrees of freedom, alleviating the prevalent issues. The gait robot joints remain aligned with the human anatomical joints during the swing and the stance phases due to the use of special bushes and dampers. The intrinsically compliant actuators on the new gait robot make it safe to work with human subjects. Increased degrees of freedom allow for natural walking dynamics instead of canceling or constraining them. The robot firmware, including the kinematic modeling, is designed using multiple adaptive neuro-fuzzy inference system to save on the computational time of the robot controller. The new robot design is finally validated for its intended use in gait rehabilitation, by employing a fuzzy logic controller and evaluating the position, velocity, and acceleration profiles of its joints. [ABSTRACT FROM AUTHOR]

Abstract In integrated circuits (ICs), the parasitic capacitance is one of the crucial factors that degrade the circuit dynamic performance; for instance, it reduces the operating frequency of the circuit. Eliminating the parasitic capacitance in organic transistors is notoriously challenging due to the inherent tradeoff between manufacturing costs and interlayer alignment accuracy. Here, we overcome such a limitation using a cost‐effective method for fabricating organic thin‐film transistors and rectifying diodes without redundant electrode overlaps. This is achieved by placing all electrodes horizontally and introducing sub‐100 nm gaps for separation. A representative small‐scale IC consisting of five‐stage ring oscillators based on the obtained nonparasitic transistors and diodes is fabricated on flexible substrates, which performs reliably at a low driving voltage of 1 V. Notably, the oscillator exhibits signal propagation delays of 5.8 μs per stage at a supply voltage of 20 V when utilizing pentacene as the active layer. Since parasitic capacitance has been a common challenge for all types of thin‐film transistors, our approach may pave the way toward the realization of flexible and large‐area ICs based on other emerging and highly performing semiconductors.

Abstract Carbon nanotubes (CNTs), owing to their superior electrical and mechanical properties, are a promising alternative to nonmetallic electrically conducting materials. In practice, cellulose as a low‐cost sustainable matrix has been used to prepare the aqueous dispersion of cellulose‐CNT (C‐CNT) nanocomposites. However, the compatibility with conventional solution‐processing and structural rearrangement for improving conductivity has yet to be determined. Herein, a straightforward route to prepare a conductive composite material from single‐walled CNTs (SWCNTs) and natural pulp is reported. High‐power shaking realizes the self‐alignment of individual SWCNTs in a cellulose matrix, resulting from the structural change in molecular orientations owing to countless collisions of zirconia beads in the aqueous mixture. The structural analysis of the dried C‐CNT films confirms that the entanglement and dispersion of C‐CNT nanowires determine the mechanical and electrical properties. Moreover, the rheological behavior of C‐CNT inks explains their coating and printing characteristics. By controlling shaking time, the electrical conductivity of the C‐CNT films with only 9 wt.% of SWCNTs from 0.9 to 102.4 S cm−1 are adjusted. the optimized C‐CNT ink is highly compatible with the conventional coating and printing processes on diverse substrates, thus finding potential applications in eco‐friendly, highly flexible, and stretchable electrodes is also demonstrated.

BACKGROUND: Hydrogels have been widely used in many research fields owing to optical transparency, good biocompatibility, tunable mechanical properties, etc. Unlike typical hydrogels in the form of an unstructured bulk material, we developed aqueous dispersions of fiber-shaped hydrogel structures with high stability under ambient conditions and their application to various types of transparent soft cell culture interfaces with anisotropic nanoscale topography. METHOD: Nanofibers based on the polyvinyl alcohol and polyacrylic acid mixture were prepared by electrospinning and hydrogelified to nano-fibrous hydrogels (nFHs) after thermal crosslinking and sulfuric acid treatment. By modifying various material surfaces with positively-charged polymers, negatively-charged superabsorbent nFHs could be selectively patterned by employing micro-contact printing or horizontally aligned by applying shear force with a wired bar coater. RESULTS: The angular distribution of bar-coated nFHs was dramatically reduced to ± 20° along the applied shear direction unlike the drop-coated nFHs which exhibit random orientations. Next, various types of cells were cultured on top of transparent soft nFHs which showed good viability and attachment while their behaviors could be easily monitored by both upright and inverted optical microscopy. Particularly, neuronal lineage cells such as PC 12 cells and embryonic hippocampal neurons showed highly stretched morphology along the overall fiber orientation with aspect ratios ranging from 1 to 14. Furthermore, the resultant neurite outgrowth and migration behaviors could be effectively controlled by the horizontal orientation and the three-dimensional arrangement of underlying nFHs, respectively. CONCLUSION: We expect that surface modifications with transparent soft nFHs will be beneficial for various biological/biomedical studies such as fundamental cellular studies, neuronal/stem cell and/or organoid cultures, implantable probe/device coatings, etc.

Abstract The current parallel ankle rehabilitation robot (ARR) suffers from the problem of difficult real-time alignment of the human-robot joint center of rotation, which may lead to secondary injuries to the patient. This study investigates type synthesis of a parallel self-alignment ankle rehabilitation robot (PSAARR) based on the kinematic characteristics of ankle joint rotation center drift from the perspective of introducing "suitable passive degrees of freedom (DOF)" with a suitable number and form. First, the self-alignment principle of parallel ARR was proposed by deriving conditions for transforming a human-robot closed chain (HRCC) formed by an ARR and human body into a kinematic suitable constrained system and introducing conditions of "decoupled" and "less limb". Second, the relationship between the self-alignment principle and actuation wrenches (twists) of PSAARR was analyzed with the velocity Jacobian matrix as a "bridge". Subsequently, the type synthesis conditions of PSAARR were proposed. Third, a PSAARR synthesis method was proposed based on the screw theory and type of PSAARR synthesis conducted. Finally, an HRCC kinematic model was established to verify the self-alignment capability of the PSAARR. In this study, 93 types of PSAARR limb structures were synthesized and the self-alignment capability of a human-robot joint axis was verified through kinematic analysis, which provides a theoretical basis for the design of such an ARR.

This work evaluates the effect of self‐alignment on the performance of bottom‐gate IGZO TFTs for AMOLED backplanes via SPICE simulation. Transient simulations are used to evaluate the row and column scaling of self‐aligned and non‐self‐aligned IGZO TFT to make quantitative comparisons in terms of line, settle and discharge time. Essentially, this work addresses the following questions: (1) given that self‐aligned TFTs have lower mobility than non‐self‐aligned TFTs due to large differences in contact resistance, does the lower overlap capacitance of self‐aligned TFTs always lead to better transient performance than non‐self‐aligned TFTs? and (2) Under what condition(s) do non‐self‐aligned TFTs become comparable to self‐aligned TFTs in terms of transient performance? [ABSTRACT FROM AUTHOR]

The current parallel ankle rehabilitation robot (ARR) suffers from the problem of difficult real-time alignment of the human-robot joint center of rotation, which may lead to secondary injuries to the patient. This study investigates type synthesis of a parallel self-alignment ankle rehabilitation robot (PSAARR) based on the kinematic characteristics of ankle joint rotation center drift from the perspective of introducing "suitable passive degrees of freedom (DOF)" with a suitable number and form. First, the self-alignment principle of parallel ARR was proposed by deriving conditions for transforming a human-robot closed chain (HRCC) formed by an ARR and human body into a kinematic suitable constrained system and introducing conditions of "decoupled" and "less limb". Second, the relationship between the self-alignment principle and actuation wrenches (twists) of PSAARR was analyzed with the velocity Jacobian matrix as a "bridge". Subsequently, the type synthesis conditions of PSAARR were proposed. Third, a PSAARR synthesis method was proposed based on the screw theory and type of PSAARR synthesis conducted. Finally, an HRCC kinematic model was established to verify the self-alignment capability of the PSAARR. In this study, 93 types of PSAARR limb structures were synthesized and the self-alignment capability of a human-robot joint axis was verified through kinematic analysis, which provides a theoretical basis for the design of such an ARR. [ABSTRACT FROM AUTHOR]

Exoskeleton robots enable individuals with impaired physical functions to perform daily activities and maintain independence. However, the discomfort experienced by users when using these devices may limit the application scope of exoskeleton robots. Therefore, this paper systematically defines and analyzes the key design factors affecting the wearing comfort of rigid exoskeleton robots by differentiating and discussing the characteristics of traditional exoskeleton robots and exoskeleton robots equipped with the self-alignment mechanism based on addressing misalignment issues. Furthermore, the various structural configurations of the Physical Human-Robot Attachment Interface (PHRAI) and related quantitative evaluation indicators are explored in depth, and the advantages and limitations of structural customized design methods combining parametric design, Three-Dimensional (3D) scanning, and 3D printing technology are evaluated. Finally, the current concerns in the research field and potential solution strategies are proposed, aiming to provide directional guidance to optimize future exoskeleton robots. The research findings are of significant value for enhancing the comfort of wearing exoskeleton robots and provide valuable theoretical and practical references for future research.

We have investigated an interference experiment of the two-slit Young experiment using an improved self-alignment (SA) liquid crystal optical control device structure. The newly developed SA process and optimization of slit structure and slit width were redesigned to micron size in order to make the interference pattern clear. As a result, we observed a clear NOT logic operation where the center peak intensity of the incident light is inverted. [ABSTRACT FROM AUTHOR]

We have developed a manufacturing process for micromirrors based on microelectromechanical systems (MEMS) technology. The process involves designing an electrostatic vertically comb-driven actuator and utilizing a self-alignment process to produce a height difference between the movable comb structure and the fixed comb structure of the micromirror. To improve the stability of the micromirror, we propose four instability models in micromirror operation with the quasi-static driving principle and structure of the micromirror considered, which can provide a basic guarantee for the performance of vertical comb actuators. This analysis pinpoints factors leading to instability, including the left and right gap of the movable comb, the torsion beams of the micromirror, and the comb-to-beams distance. Ultimately, the voltages at which device failure occurs can be determined. We successfully fabricated a one-dimensional micromirror featuring a 0.8 mm mirror diameter and a 30 μm device layer thickness. The height difference between the movable and fixed comb structures was 10 μm. The micromirror was able to achieve a static mechanical angle of 2.25° with 60 V@DC. Stable operation was observed at voltages below 60 V, in close agreement with the theoretical calculations and simulations. At the driving voltage of 80 V, we observed the longitudinal displacement movement of the comb fingers. Furthermore, at a voltage of 129 V, comb adhesion occurred, resulting in device failure. This failure voltage corresponds to the lateral torsional failure voltage. [ABSTRACT FROM AUTHOR]

Abstract Background Hydrogels have been widely used in many research fields owing to optical transparency, good biocompatibility, tunable mechanical properties, etc. Unlike typical hydrogels in the form of an unstructured bulk material, we developed aqueous dispersions of fiber-shaped hydrogel structures with high stability under ambient conditions and their application to various types of transparent soft cell culture interfaces with anisotropic nanoscale topography. Method Nanofibers based on the polyvinyl alcohol and polyacrylic acid mixture were prepared by electrospinning and hydrogelified to nano-fibrous hydrogels (nFHs) after thermal crosslinking and sulfuric acid treatment. By modifying various material surfaces with positively-charged polymers, negatively-charged superabsorbent nFHs could be selectively patterned by employing micro-contact printing or horizontally aligned by applying shear force with a wired bar coater. Results The angular distribution of bar-coated nFHs was dramatically reduced to ± 20° along the applied shear direction unlike the drop-coated nFHs which exhibit random orientations. Next, various types of cells were cultured on top of transparent soft nFHs which showed good viability and attachment while their behaviors could be easily monitored by both upright and inverted optical microscopy. Particularly, neuronal lineage cells such as PC 12 cells and embryonic hippocampal neurons showed highly stretched morphology along the overall fiber orientation with aspect ratios ranging from 1 to 14. Furthermore, the resultant neurite outgrowth and migration behaviors could be effectively controlled by the horizontal orientation and the three-dimensional arrangement of underlying nFHs, respectively. Conclusion We expect that surface modifications with transparent soft nFHs will be beneficial for various biological/biomedical studies such as fundamental cellular studies, neuronal/stem cell and/or organoid cultures, implantable probe/device coatings, etc.

This paper demonstrates that "completely-jigless" assembly of a model product that requires fitting accuracy at the level of industrial products is possible by using a universal hand with four parallel stick fingers mounted on a conventional position-control-based industrial robot. Assuming that each part is taken out of the parts bin and temporarily placed on the work table, the accuracy required for precise fitting cannot be achieved with a vision sensor alone. Introducing an appropriate grasping strategy, the initial position error of the part is absorbed by self-alignment in the process of grasping. Once the alignment is completed, the pose of the grasped part is fixed and jigless assembly is possible with a conventional industrial robot, which has high repeatability. In this paper, we use a gear unit as an example of an industrial product and present some grasping strategies with the universal hand. We also propose some subsequent assembly strategies for shafts and gears. Using those grasping and assembly strategies, it is shown that jigless assembly of the gear unit was successfully completed in the experiment. Although the target product in this paper is specific, the assembly elements in this product, such as shaft screwing, bearing insertion, and gear meshing, are also included in many other products. Therefore, the methods shown in this paper can be applied to other products. [ABSTRACT FROM AUTHOR]

The structure of steering gear’s HATLAPA mechanism is analyzed. It is shown that presence of redundant constraints in it increases laboriousness of gear montage and respectively worsen maintainability. On the basis of provided analysis developed mechanism with reduced more than twice redundant constrainsts number.

We have investigated the Young's interference experiment using a self-aligned liquid crystal optical control device. This device can be operated by changing the control of the optical phase of the liquid crystal, and we have observed the change in the interference state between right and left position of the slit. To reduce the problem of stray light, the electrode structure was self-aligned, and the alignment of the liquid crystal director was closely changed. As a result, observed voltage change between without and voltage application, the logically 'NOT' operation was achieved at the Sinc function. [ABSTRACT FROM AUTHOR]

We have developed a manufacturing process for micromirrors based on microelectromechanical systems (MEMS) technology. The process involves designing an electrostatic vertically comb-driven actuator and utilizing a self-alignment process to produce a height difference between the movable comb structure and the fixed comb structure of the micromirror. To improve the stability of the micromirror, we propose four instability models in micromirror operation with the quasi-static driving principle and structure of the micromirror considered, which can provide a basic guarantee for the performance of vertical comb actuators. This analysis pinpoints factors leading to instability, including the left and right gap of the movable comb, the torsion beams of the micromirror, and the comb-to-beams distance. Ultimately, the voltages at which device failure occurs can be determined. We successfully fabricated a one-dimensional micromirror featuring a 0.8 mm mirror diameter and a 30 μm device layer thickness. The height difference between the movable and fixed comb structures was 10 μm. The micromirror was able to achieve a static mechanical angle of 2.25° with 60 V@DC. Stable operation was observed at voltages below 60 V, in close agreement with the theoretical calculations and simulations. At the driving voltage of 80 V, we observed the longitudinal displacement movement of the comb fingers. Furthermore, at a voltage of 129 V, comb adhesion occurred, resulting in device failure. This failure voltage corresponds to the lateral torsional failure voltage.

To reduce the impact of offshore launching platform motion and swaying on the self-alignment accuracy of a launch vehicle, a rapid self-alignment strategy, which involves an optimal combination of anti-swaying coarse alignment (ASCA), backtracking navigation, and reverse Kalman filtering is proposed. During the entire alignment process, the data provided by the strapdown inertial navigation system (SINS) are stored and then applied to forward and backtrack self-alignment. This work elaborates the basic principles of coarse alignment and then analyzes the influence of ASCA time on alignment accuracy. An error model was built for the reverse fine alignment system. The coarse alignment was carried out based on the above work, then the state of the alignment system was retraced using the reverse inertial navigation solution and reverse Kalman filtering with the proposed strategy. A cycle-index control function was designed to approximate strict backtracking navigation. Finally, the attitude error was compensated for after the completion of the first and the last forward navigation. To demonstrate the effectiveness of the proposed strategy, numerical simulations were carried out in a scenario of launch vehicle motion and swaying. The proposed strategy can maximize the utilization of SINS data and hence improve the alignment accuracy and further reduce the alignment time. The results show that the fully autonomous alignment technology of the SINS can replace the complex optical aiming system and realize the determination of the initial attitude of a launch vehicle before launch. [ABSTRACT FROM AUTHOR]

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Featured Application: New approaches to design efficient RF devices that use LCs. We evaluated hexadecyltrimethylammonium bromide (HTAB) for liquid crystals (LCs) in layered ITO cells with various cell gap conditions. HTAB is a surfactant that can self-align vertically on the surface of indium tin oxide (ITO) substrates and induce homeotropic alignment of the LC molecules. For implementing RF devices with HTAB and LCs, we should consider limitations caused by the design conditions which are different from conventional liquid crystal displays such as cell gap. We quantified the concentration of HTAB ([HTAB]) that is necessary to form and maintain a sufficiently dense vertical alignment of 5CB (4-Cyano-4′-pentylbiphenyl). The required [HTAB] for full-homeotropic alignment was increased to the cell gap until it was too large to support the transfer of the surface alignment to the LC molecules, due to the weak anchoring nature of HTAB. We also showed the phase-change characteristic of the LC mixture related to [HTAB] for the design of RF devices driven by light or heat. This study may help to guide the development of new approaches to designing efficient RF devices that use LCs. [ABSTRACT FROM AUTHOR]

Amorphous oxide semiconductor thin‐film transistors (AOS TFTs) have shown significant potential in the applications of increasingly advanced transparent and flexible electronic devices, where high speed, high transparency, and low power consumption are highly demanded. Yet, typical back‐channel etch (BCE) configuration used in the majority of TFTs still suffers from poor gate controllability, severe electrical field dispersion, relatively large parasitic capacitance and contact resistance. Here, a new embedded structure for TFTs with self‐alignment and even simpler fabrication process, outperforming conventional BCE counterpart in above aspects, is proposed in this work. More concentrated electrical field, improved gate control ability accompanied with lower contact resistance are achieved in the embedded TFTs. Consequently, superior electrical characteristics with subthreshold swing of 106.7 mV dec−1 and mobility as high as 32.10 cm2 V−1 s−1 are obtained. In addition, leakage current as well as contact resistance evidently decline compared to that in traditional BCE TFTs. By the assistance of Silvaco TCAD simulation, the performance and mechanism behind are cross‐validated from another perspective. Overall, such embedded configuration has equipped TFTs with appealing performance and it is also possible to enable other devices exploiting such structure with new possibility and thus a broader application. [ABSTRACT FROM AUTHOR]

There exist vast areas of offshore wind resources with water depths greater than 100 m that require floating structures. This paper provides a detailed analysis on the hydrostatic stability characteristics of a novel floating wind turbine concept. The preliminary design supports an 8 MW horizontal-axis wind turbine with a custom self-aligning single-point mooring (SPM) floater, which is to be constructed within the existing shipyard facilities in the Maltese Islands, located in the Central Mediterranean Sea. The theoretical hydrostatic stability calculations used to find the parameters to create the model are validated using SESAM®. The hydrostatic stability analysis is carried out for different ballast capacities whilst also considering the maximum axial thrust induced by the rotor during operation. The results show that the entire floating structure exhibits hydrostatic stability characteristics for both the heeling and pitching axes that comply with the requirements set by the DNV ST-0119 standard. Numerical simulations using partial ballast are also presented. [ABSTRACT FROM AUTHOR]

Powered knee exoskeletons have shown potential for mobility restoration and power augmentation. However, the benefits of exoskeletons are partially offset by some design challenges that still limit their positive effects on people. Among them, joint misalignment is a critical aspect mostly because the human knee joint movement is not a fixed-axis rotation. In addition, remarkable mass and stiffness are also limitations. Aiming to minimize joint misalignment, this paper proposes a bio-inspired knee exoskeleton with a joint design that mimics the human knee joint. Moreover, to accomplish a lightweight and high compliance design, a high stiffness cable-tension amplification mechanism is leveraged. Simulation results indicate our design can reduce 49.3 and 71.9% maximum total misalignment for walking and deep squatting activities, respectively. Experiments indicate that the exoskeleton has high compliance (0.4 and 0.1 Nm backdrive torque under unpowered and zero-torque modes, respectively), high control bandwidth (44 Hz), and high control accuracy (1.1 Nm root mean square tracking error, corresponding to 7.3% of the peak torque). This work demonstrates performance improvement compared with state-of-the-art exoskeletons. [ABSTRACT FROM AUTHOR]

We report on self-aligned Ti TES single-photon detectors embedded in a 1550 nm optical cavity. The circular TES chip is shaped with a dry-etch process from the backside to protect the TES and wiring from possible damage and aligned to a single-mode fiber using a standard fiber ferrule and a matching sleeve. The critical temperature of Ti film is about 300 mK, resulting in a relatively short time constant of 1.3 μs. By choosing an active area of 15 × 15 μm2, our optical Ti TES can distinguish single photons at 1550 nm and reaches a system photon detection efficiency of 55% and an energy resolution of about 0.7 eV. [ABSTRACT FROM AUTHOR]

Recently, particle manipulation in non-Newtonian fluids has attracted increasing attention because of a good particle focusing toward the mid-plane of a channel. In this research, we proposed a simple and robust fabrication method to make a microchannel with various T-shaped cross-sections for particle focusing and separation in a viscoelastic solution. SU-8-based soft lithography was used to form three different types of microchannels with T-shaped cross-sections, which enabled self-alignment and plasma bonding between two PDMS molds. The effects of the flow rate and geometric shape of the cross-sections on particle focusing were evaluated in straight microchannels with T-shaped cross-sections. Moreover, by taking images from the top and side part of the channels, it was possible to confirm the position of the particles three-dimensionally. The effects of the corner angle of the channel and the aspect ratio of the height to width of the T shape on the elasto-inertial focusing phenomenon were evaluated and compared with each other using numerical simulation. Simulation results for the particle focusing agreed well with the experimental results both in qualitatively and quantitatively. Furthermore, the numerical study showed a potential implication for particle separation depending on its size when the aspect ratio of the T-shaped microchannel and the flow rate were appropriately leveraged. [ABSTRACT FROM AUTHOR]

This article studies magnetic forces between transmitter (Tx) and receiver (Rx) coils in an inductive power transfer (IPT) system aiming to use those forces to align the coils and, consequently, improve power transfer. Due to its popularity, the analysis is conducted on a series–series compensated IPT system with planar spiral coils. The proposed method utilizes the bifurcation operation mode of the system and unloaded resonating receiver to maximize attractive force between magnetic couplers. Three-dimensional finite-element method simulations indicate that high-power IPT systems can develop enough attractive force to align coils even under nominal current. Regardless of the coil shape, e.g., spiral or Double-D (DD), the attractive forces tend to align the coils. Hence, a smart charging station can be devised based on self-aligning capability. Furthermore, this article proposes a mechanical structure to facilitate the attractive lateral force for the alignment of high power applications, i.e., wireless fast-charging stations. The forces are analyzed, modeled, and simulated for a 100-kW IPT system with an operating frequency of 20 kHz, while the self-aligning capability is experimentally verified on a downscale 11-kW prototype. [ABSTRACT FROM AUTHOR]

Powered knee exoskeletons have shown potential for mobility restoration and power augmentation. However, the benefits of exoskeletons are partially offset by some design challenges that still limit their positive effects on people. Among them, joint misalignment is a critical aspect mostly because the human knee joint movement is not a fixed-axis rotation. In addition, remarkable mass and stiffness are also limitations. Aiming to minimize joint misalignment, this paper proposes a bio-inspired knee exoskeleton with a joint design that mimics the human knee joint. Moreover, to accomplish a lightweight and high compliance design, a high stiffness cable-tension amplification mechanism is leveraged. Simulation results indicate our design can reduce 49.3 and 71.9% maximum total misalignment for walking and deep squatting activities, respectively. Experiments indicate that the exoskeleton has high compliance (0.4 and 0.1 Nm backdrive torque under unpowered and zero-torque modes, respectively), high control bandwidth (44 Hz), and high control accuracy (1.1 Nm root mean square tracking error, corresponding to 7.3% of the peak torque). This work demonstrates performance improvement compared with state-of-the-art exoskeletons.

Recently, black-box domain adaptation attracts a lot of attention. It is a new concept to realize domain adaptation of instance image classification with only a cloud API service, reflecting the focus on development of cloud services and concerns about data security. However, the existing black-box domain adaptation methods always only use high-confidence image samples which limits their classification performance. We propose a self-alignment approach to realize black-box domain adaptation. First, an initial model is constructed for target domain. Then, we put target data into source model API to obtain the pseudo-labels and divide the target data into high-confidence and low-confidence parts according to their pseudo-label confidences. By matching the data distributions between these two parts and self-supervised learning on high-confidence part, the classification performance of initial model on both parts samples can be boosted respectively. Information maximization is also applied to further improve classification performance. Experiment results confirm that our method achieves the state-of-the-art performance on image classification. [ABSTRACT FROM AUTHOR]

For the alignment problem of strapdown inertial navigation system (SINS) under the complex environment of unknown latitude, angular oscillation interference, and line interference, the ant colony simulated annealing algorithm of gravity vector optimization is proposed to obtain the gravity apparent motion vector optimization equation, and the polynomial fitting method is proposed to simultaneously perform latitude estimation and self-alignment in combination with the alignment principle of SINS. Simulations and experiments show that the proposed method has more robust anti-interference capability than the traditional interference-based alignment method, the latitude estimation accuracy is improved by six times, the self-alignment yaw angle error RMSE value after obtaining the latitude is within 0.7°, and the roll angle and pitch angle error values are within 0.1°. [ABSTRACT FROM AUTHOR]

Non-covalent functionalization of graphene (Gr) with conducting polymers (CPs) improves the electrical and mechanical properties of both materials owing to the noncovalent π-π stacking interaction between the surface and the aromatic rings in CPs. However, a comprehensive understanding of the self-organization and chain orientation of CPs on the Gr surface remains lacking, which may limit the engineering of CP-Gr complexes with optimized morphology for optoelectronic applications. This study focuses on the Density Functional Theory (DFT) calculations and homemade Python programming code to investigate the self-organization of donor (D)-acceptor (A) type molecules on the Gr surface, aiming to elucidate factors governing the direction of self-alignment. Specifically, basic structural parameters characterizing the aromatic D-A molecules, such as the intramolecular aromatic ring distances, are explored to determine the rules for the preferred alignment direction of the CP monomers on the Gr surface, either in armchair or zigzag paths. Additionally, the influence of Gr on the morphological properties of aromatic molecules, variations in interaction energies between Gr and D-A-D systems with changing A units, and the impact of Gr size on molecular fitting characteristics are examined. The accurate determination of chain alignment direction, which can be applied for all conjugated small molecules and polymers at 2D material interfaces is crucial for guiding experimental studies aimed at tailoring structures and enhanced properties, such as promoting the crystalline domains with high electrical conductivity. [Display omitted] [ABSTRACT FROM AUTHOR]

Optical metasurfaces address a plethora of applications in planar optics, as they enable precise control of the phase, amplitude, and polarization of light at nanoscale interaction lengths. However, their implementation requires surface nanostructuring, based on complex design and fabrication methods. In addition, exploiting narrow spectral features, e.g., for sensing, is accompanied by high demands in terms of precise post-process alignments of probing light--impractical for compact optical systems. Here, the realization of plasmonic metasurfaces, based on silver nanoparticles (AgNPs) and using a solution-based growth method, is demonstrated. The particle growth is mediated by localized surface plasmon resonances. The resulting nanostructures are directly applicable as self-optimized metasurfaces in optical systems, as their fabrication and probing procedures allow the use of common--photonic and plasmonic--platforms. Information regarding the electromagnetic (EM) environment is stored during the fabrication via distinct particle positions and dimensions. The resulting optical response is inherently sensitive to deviations from this EM environment--enabling high-performance nanoplasmonic sensing with a maximum discrete Figure of Merit* (FoM*max of 968 without the need for post-process alignments. [ABSTRACT FROM AUTHOR]

Electrospinning, a process that converts a solution or melt droplet into an ejected jet under a high electric field, is a well-established technique to produce one-dimensional (1D) fibers or two-dimensional (2D) randomly arranged fibrous meshes. Nevertheless, the direct electrospinning of fibers into controllable three-dimensional (3D) architectures is still a nascent technology. Here, we apply near-field electrospinning (NFES) to directly write arbitrarily shaped 3D structures through consistent and spatially controlled fiber-by-fiber stacking of polyvinylidene fluoride (PVDF) fibers. An element central to the success of this 3D electrospinning is the use of a printing paper placed on the grounded conductive plate and acting as a fiber collector. Once deposited on the paper, residual solvents from near-field electrospun fibers can infiltrate the paper substrate, enhancing the charge transfer between the deposited fibers and the ground plate via the fibrous network within the paper. Such charge transfer grounds the deposited fibers and turns them into locally fabricated electrical poles, which attract subsequent in-flight fibers to deposit in a self-aligned manner on top of each other. This process enables the design and controlled fabrication of electrospun 3D structures such as grids, walls, hollow cylinders, and other 3D logos. As such, this technique has the potential to advance the existing electrospinning technologies in constructing 3D structures for biomedical, microelectronics, and MEMS/NMES applications.

Self‐connection is defined as an (1) awareness of oneself, (2) acceptance of oneself based on this awareness, and (3) alignment of one's behavior with this awareness. Although some promising results suggest that self‐connection uniquely contributes to well‐being, they have relied on an untested, single‐item measure. To advance empirical examination of self‐connection and its role in well‐being, the current research developed and validated a 12‐item Self‐Connection Scale (SCS). We recruited a total of 1,469 participants across three studies to examine the SCS and its three underlying components. Using both exploratory and confirmatory factor analyses, we found evidence supporting the factor structure and inter‐item reliability as well as evidence of construct, concurrent, and incremental validity. Importantly, results from three studies suggest that the SCS is associated with multiple important indicators of health and well‐being. The scale also demonstrated incremental validity beyond mindfulness, authenticity, self‐concept clarity, self‐compassion, and self‐acceptance in its association with various mental health and well‐being indicators. Thus, the SCS provides a valuable tool to measure and examine self‐connection and its relationship to well‐being and other important psychological outcomes. [ABSTRACT FROM AUTHOR]

Intrinsic graphene features semi-metallic characteristics that limit its applications in electronic devices, whereas graphene nanoribbons (GNRs) are promising semiconductors because of their bandgap-opening feature. However, the controllable mass-fabrication of high-quality GNR arrays remains a major challenge. In particular, the in situ growth of GNR arrays through template-free chemical vapor deposition (CVD) has not been realized. Herein, we report a template-free CVD strategy to grow large-area, high-quality and self-aligned GNR arrays on liquid copper surface. The width of as-grown GNR could be optimized to sub-10 nm with aspect ratio up to 387, which is higher than those of reported CVD-GNRs. The study of the growth mechanism indicates that a unique comb-like etching-regulated growth process caused by a trace hydrogen flow guides the formation of the mass-produced self-aligned GNR arrays. Our approach is operationally simple and efficient, offering an assurance for the use of GNR arrays in integrated circuits. [ABSTRACT FROM AUTHOR]

This article presents a novel substrate-agnostic self-alignment technology with submicrometer alignment accuracy targeted for heterogeneous integrated systems. This self-alignment technology, referred to as PSAS-to-PSAS self-alignment, incorporates positive self-alignment structures (PSAS) or reflowed patterned photoresist structures that couple with other PSAS to achieve submicrometer alignment accuracy without the need for an advanced placement tool. The PSAS-to-PSAS self-alignment technology is non-substrate invasive and hence does not consume any substrate real estate. These PSAS structures can also be fabricated atop any material substrate; hence, this technology is suitable for heterogeneous integrated systems where a variety of different material substrates may be incorporated. This article discusses this PSAS-to-PSAS self-alignment technology and it provides a design analysis relating the inter-substrate gap between aligning substrates and the dimensions of the PSAS structures. The fabrication of the PSAS on two separate substrates is then performed, followed by a manual assembly process to couple the PSAS on one substrate to the PSAS on the other aligning substrate. Vernier scales are incorporated on these substrates to measure the misalignment between said substrates; submicrometer alignment is recorded. As these structures may also enable a non-permanent system configuration, alignment repeatability measurements were also performed. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotube (SWCNT)-based polymer matrix composites have been developed for various applications such as transparent electrodes and heaters. To enhance the conductivity of the SWCNT/polymer matrix, diverse alignment technologies for the directional alignment of carbon nanoparticles in the polymer matrix have been studied. In the present study, we demonstrate macroscale dielectrophoretic self-alignment of SWCNTs with carboxymethyl cellulose (CMC) using a high alternating current (AC) voltage (150 Vpp, 10 kHz) without the use of a semiconductor for the fabrication of electrodes. Owing to the latitudinal alignment of the SWCNTs by the AC field, the resistance values of the SWCNT substrates differ in the directions. Furthermore, transfer of the aligned SWCNTs onto the nitrocellulose (NC) substrate using dimethyl sulfoxide (DMSO) evaporation yields a one-directional multiple aligned SWCNTs/transparent NC sheet that provides approximately 3.3 times higher conductivity than that achieved by alignment in another direction.

Abstract In this study, particle focusing phenomena are studied in parallelogram and rectangular cross-sectioned microchannels of varying aspect ratio. In contrast to prior work the microchannels were fabricated using anisotropic wet etching of a Si wafer, plasma bonding, and self-alignment between the Si channel and the PDMS mold. It is shown that the inertial focusing points of the fabricated microchannels of parallelogram and rectangular cross-section were modified as the aspect ratio of the microchannels changed. The particle focusing points of the parallelogram profiled microchannel are compared with those of the rectangular microchannel through experimental measurements and CFD simulation. It is shown that particles can be efficiently focused and separated at a relatively low Reynolds number using a parallelogram profiled microchannel with a low aspect ratio.

We evaluated hexadecyltrimethylammonium bromide (HTAB) for liquid crystals (LCs) in layered ITO cells with various cell gap conditions. HTAB is a surfactant that can self-align vertically on the surface of indium tin oxide (ITO) substrates and induce homeotropic alignment of the LC molecules. For implementing RF devices with HTAB and LCs, we should consider limitations caused by the design conditions which are different from conventional liquid crystal displays such as cell gap. We quantified the concentration of HTAB ([HTAB]) that is necessary to form and maintain a sufficiently dense vertical alignment of 5CB (4-Cyano-4′-pentylbiphenyl). The required [HTAB] for full-homeotropic alignment was increased to the cell gap until it was too large to support the transfer of the surface alignment to the LC molecules, due to the weak anchoring nature of HTAB. We also showed the phase-change characteristic of the LC mixture related to [HTAB] for the design of RF devices driven by light or heat. This study may help to guide the development of new approaches to designing efficient RF devices that use LCs.

There exist vast areas of offshore wind resources with water depths greater than 100 m that require floating structures. This paper provides a detailed analysis on the hydrostatic stability characteristics of a novel floating wind turbine concept. The preliminary design supports an 8 MW horizontal-axis wind turbine with a custom self-aligning single-point mooring (SPM) floater, which is to be constructed within the existing shipyard facilities in the Maltese Islands, located in the Central Mediterranean Sea. The theoretical hydrostatic stability calculations used to find the parameters to create the model are validated using SESAM®. The hydrostatic stability analysis is carried out for different ballast capacities whilst also considering the maximum axial thrust induced by the rotor during operation. The results show that the entire floating structure exhibits hydrostatic stability characteristics for both the heeling and pitching axes that comply with the requirements set by the DNV ST-0119 standard. Numerical simulations using partial ballast are also presented.

To reduce the impact of offshore launching platform motion and swaying on the self-alignment accuracy of a launch vehicle, a rapid self-alignment strategy, which involves an optimal combination of anti-swaying coarse alignment (ASCA), backtracking navigation, and reverse Kalman filtering is proposed. During the entire alignment process, the data provided by the strapdown inertial navigation system (SINS) are stored and then applied to forward and backtrack self-alignment. This work elaborates the basic principles of coarse alignment and then analyzes the influence of ASCA time on alignment accuracy. An error model was built for the reverse fine alignment system. The coarse alignment was carried out based on the above work, then the state of the alignment system was retraced using the reverse inertial navigation solution and reverse Kalman filtering with the proposed strategy. A cycle-index control function was designed to approximate strict backtracking navigation. Finally, the attitude error was compensated for after the completion of the first and the last forward navigation. To demonstrate the effectiveness of the proposed strategy, numerical simulations were carried out in a scenario of launch vehicle motion and swaying. The proposed strategy can maximize the utilization of SINS data and hence improve the alignment accuracy and further reduce the alignment time. The results show that the fully autonomous alignment technology of the SINS can replace the complex optical aiming system and realize the determination of the initial attitude of a launch vehicle before launch.

Recently, particle manipulation in non-Newtonian fluids has attracted increasing attention because of a good particle focusing toward the mid-plane of a channel. In this research, we proposed a simple and robust fabrication method to make a microchannel with various T-shaped cross-sections for particle focusing and separation in a viscoelastic solution. SU-8-based soft lithography was used to form three different types of microchannels with T-shaped cross-sections, which enabled self-alignment and plasma bonding between two PDMS molds. The effects of the flow rate and geometric shape of the cross-sections on particle focusing were evaluated in straight microchannels with T-shaped cross-sections. Moreover, by taking images from the top and side part of the channels, it was possible to confirm the position of the particles three-dimensionally. The effects of the corner angle of the channel and the aspect ratio of the height to width of the T shape on the elasto-inertial focusing phenomenon were evaluated and compared with each other using numerical simulation. Simulation results for the particle focusing agreed well with the experimental results both in qualitatively and quantitatively. Furthermore, the numerical study showed a potential implication for particle separation depending on its size when the aspect ratio of the T-shaped microchannel and the flow rate were appropriately leveraged.