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In order to scientifically allocate rural landscape resources, reasonably plan rural tourism space, and ensure that the local characteristics of the countryside are not homogenized when carrying out rural landscape design, this paper studies rural landscape design strategies based on deep learning models. The extreme learning machine algorithm, DBN-RBM algorithm model and the improved DBN-DELM algorithm are the main technical means to obtain research data and parameter calibration results for tourism planning and development work, and the rural planning direction and planning theme is determined through the rural landscape design pre-analysis work. The data show that the main motives of tourists’ rural experience tourism are close to nature 85.90% and leisure vacation 75%, followed by understanding culture 45.30%, novelty 30.70%, parent-child education 29.20%, health retreat 30.40%, and business meeting 5.90%. In this paper, the study of rural landscape planning and design can effectively alleviate the contradiction between people’s production and living and ecological environment and coordinate the benign development of rural and tourism elements in their respective spaces.

Background: Early dislocation following primary total hip arthroplasty (THA) is a rare but devastating complication and represents a source of patient morbidity and financial burden to the healthcare system. The objective of this study was to identify patient characteristics and comorbidities that are associated with increased early in-hospital dislocation rates following primary THA. Methods: A retrospective cohort study was conducted using patient data from the Nationwide Inpatient Sample (NIS) database; we identified patients who had undergone THA from 2016 to 2019 and compared those with an early periprosthetic dislocation prior to discharge to those without. The patient characteristics and comorbidities were compared using univariate analysis with a subsequent investigation of statistically significant variables using multivariate analysis. The variables were compared using chi square, Fisher's exact test, and independent sample t-tests with data assessed using odds ratio with 95% confidence intervals. Results: A total of 5151 patients sustained an early dislocation compared to 362,743 who did not. Those who sustained an in-hospital dislocation were more likely to share the following characteristics: female sex (OR 1.21, p < 0.01), age > 70 (OR 1.45, p < 0.01), Caucasian ethnicity (OR 1.22, p < 0.01), SLE (OR 1.87, p < 0.01), and Parkinson's disease (OR 1.93, p < 0.01). Certain characteristics were also associated with decreased odds of having an in-hospital dislocation including elective surgery (OR 0.14, p < 0.01), tobacco use (OR 0.8, p < 0.01), diabetes without complications (OR 0.87, p < 0.01), and a history of heart valve replacement (OR 0.81, p < 0.01). The length of stay was significantly longer (4.7 days vs. 2.3 days) as was the total hospital charges (USD $101,517 vs. USD $66,388) for the early in-hospital dislocation group. Conclusions: Several patient characteristics and comorbidities are associated with early in-hospital dislocation episodes following total hip arthroplasty including female sex, age > 70, non-elective surgery, SLE, and Parkinson's. This information may be useful to help guide intraoperative implant selection and/or postoperative protocol in select patient populations to limit early instability as well as decrease the financial burden associated with this postoperative complication. [ABSTRACT FROM AUTHOR]

Thermal camouflage, which is used to conceal objects in the infrared vision for confrontation with infrared detection in civilian or military applications, has garnered increasing attraction and interest recently. Compared with conductive thermal camouflage, that is to tune heat conduction to achieve equivalent temperature fields, radiative thermal camouflage, based on emissivity engineering, is more promising and shows much superiority in the pursuit of dynamic camouflage technology when resorting to stimuli-responsive materials. In this paper, we demonstrate the emissivity-engineered radiative metasurface to realize dynamic thermal camouflage functionality via a flying laser heat source on the metal-liquid-crystal-metal (MLCM) platform. We employ a rigorous coupled-wave algorithm to calculate the surface emissivity of Au/LC/Au microstructures, where the LC-orientation angle distribution is quantified by minimizing the emitted thermal energy standard deviation throughout the whole plate. Emissivity engineering on the MCLM platform is attributed to multiple magnetic polariton resonance, and agrees well with the equivalent electric circuit analysis. Through this electrical modulation strategy, the moving hot spot in the original temperature field is erased and a uniform temperature field is observed in the infrared camera instead, demonstrating the very good dynamic thermal camouflage functionality. The present MLCM-based radiative metasurface may open avenues for high-resolution emissivity engineering to realize novel thermal functionality and develop new applications for thermal metamaterials and meta-devices.

Purpose: The purpose of this study is to characterize the effect of sex and the influence of oral contraception usage on musculotendinous injury (MTI). Current literature suggests a disparity in the incidence of MTI between males and females. This may be attributed to inherent biological differences between the sexes, such as in the sex hormonal milieu. There is a lack of information associating sex hormone milieu and MTI. Methods: We searched the PearlDiver database (a for-fee healthcare database) for males, females taking oral contraceptives (OC), and eumenorrheic females not taking any form of hormonal contraceptives (non-OC) 18–39 yr old. The three populations were matched by age and body mass index. We queried the database for lower-extremity skeletal MTI diagnoses in these groups. Results: Each group contained 42,267 patients with orthopedic injuries. There were a total of 1476 (3.49%) skeletal MTI in the male group, 1078 (2.55%) in non-OC females, and 231 (0.55%) in OC females. Both the non-OC and the OC groups had a significantly smaller proportion of MTI than males (P < 0.0001), and therefore these groups were less likely (adjusted odds ratios, 0.72 and 0.15, respectively) to experience MTI when controlled for potential covariates. Conclusions: In this study, we show that females are less likely to develop MTI to total injuries, when compared with males, with OC using females being least likely followed by non-OC females. These results are consistent with other epidemiological studies; however, overall results in the literature are variable. This study adds to the emerging body of literature on sex hormone–influenced musculoskeletal injury but, more specifically, MTI, which have not been rigorously investigated. [ABSTRACT FROM AUTHOR]

To improve the corrosion resistance of 6061 Al in electric vehicle battery packs, a composite coating of nano-SiO2/Micro-Arc oxidation (MAO) ceramic structure was prepared on its surface. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PDP) were used to evaluate the corrosion resistance of the specimens after 7 days immersion in a 3.5% NaCl solution. The corrosion resistance of the prefabricated coatings was measured via local electrochemical impedance spectroscopy (LEIS). Confocal microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to characterize the microstructure and phase composition of the specimens. An energy dispersive spectrometer (EDS) was used to detect the elemental composition of the surface of the specimen. The results showed that the specimen with nano-SiO2/MAO composite coating had the least amount of micropores and superior corrosion resistance. The global electrochemical impedance of nano-SiO2/MAO composite coating was 1.1 times higher than that of the MAO coating and 8.4 times higher than that of the 6061 Al. When the coating was defective, the local electrochemical impedance of the nano-SiO2/MAO composite coating was still two times higher than that of the MAO coating. In the presence of scratches, the nano-SiO2/MAO composite coating still showed high corrosion resistance. The collapse corrosion mechanism of the nano-SiO2/MAO composite coating was proposed. [ABSTRACT FROM AUTHOR]

BACKGROUND: Whether waste polyethylene terephthalate (PET) can be effectively recycled is one of the main challenges of the current environmental problems. The hydrolysis of dimethyl terephthalate (DMT) to terephthalic acid (TPA) over Nb‐modified HZSM‐5 zeolite was studied. Nb/HZSM‐5 zeolites with different loadings were prepared and characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, NH3‐temperature programmed desorption and pyridine adsorption infrared spectroscopy. The effects of different reaction conditions on the conversion of DMT and TPA yield were investigated. RESULTS: The yield of TPA strongly depends on the reaction conditions and the loading of Nb. The niobium phase exists in the form of Nb2O5 on the zeolite and interacts with the surface of HZSM‐5 to produce the active site of Brønsted acid. The yield of TPA is closely related to the concentration of Brønsted acid sites. On 0.6Nb/HZSM‐5 catalyst, the yield of TPA is highest, at about 94%. CONCLUSION: Nb/HZSM‐5 catalyst has excellent catalytic activity and high stability for DMT hydrolysis. In addition, the product TPA prepared in this study can be directly applied to the current PET production supply chain, providing a promising catalytic route. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

With the increasing development of infrared (IR) detection technologies for both military and civil applications, IR anti‐detection technologies, also known as thermal camouflage technologies, have attracted great attention in recent years. Decreasing the surface emissivity may be effective for high‐temperature targets, but fails for adaptive thermal camouflage in dynamic scenes where the background temperature varies. In this work, we demonstrate a flexible Janus functional film (JFF) for adaptive thermal camouflage. The JFF consists of a low emissivity (low‐ε) layer and a high heat capacity (high‐C) layer. The low‐ε layer can effectively suppress the IR radiation of the objects, thus reducing the temperature of the objects in IR camera, while the high‐C layer can make similar thermal response as the background. According to different environmental conditions, different surfaces of JFF can be selected as camouflage surface to achieve static or dynamic thermal camouflage effect. What's more, the substrate materials of JFF (i.e., high‐density polyethylene (HDPE), silica gel (SG)) enable the film with good flexibility and realize the encapsulation of the functional filler, thus improving its reliability of resisting water and oxygen. Such flexible JFF with high reliability, easy scalability, and low cost may hold great promise for broad applications in adaptive thermal camouflage. [ABSTRACT FROM AUTHOR]

As a result of the vast Young's moduli difference between an inorganic semiconducting channel and flexible substrates, flexible optoelectronic devices readily lose their functionality through material delamination and local fracturing, which lead to short‐circuiting of devices. For this study, we synthesized a catechol‐containing polysiloxane (CFPS) adhesive and applied it to ZnO nanoparticle (NP) assembly on plastic substrates for flexible UV detector applications. The 30 nm thick CFPS adhesive can anchor 70 nm thick ZnO NPs strongly through a coordination bond, thereby forming an ultra‐stable ZnO NP channel layer. A peeling test of ZnO NP layer was conducted using transparent tape (Scotch®; 3 M Inc.). The ZnO NPs were firmly immobilized, reflecting the outstanding mechanical stability of CFPS adhesives. A UV detector also exhibited stable photo‐response performance even after a thousand iterations of bending with 3 mm curvature radii. The result indicates the polycyclosiloxane‐based flexible device as promising for wearable detector applications. [ABSTRACT FROM AUTHOR]

In dynamic manufacturing and warehousing environments, the work scene made it impossible for workers to sit, so workers suffer from muscle fatigue of the lower limb caused by standing or squatting for a long period of time. In this paper, a semi-active exoskeleton used to reduce the muscle fatigue of the lower limb was designed and evaluated. (i) Background: The advantages and disadvantages of assistive exoskeletons developed for industrial purposes were introduced. (ii) Simulation: The process of squatting was simulated in the AnyBody.7.1 software, the result showed that muscle activity of the gluteus maximus, rectus femoris, vastus medialis, vastus lateralis, vastus intermedius, and erector spinae increased with increasing of knee flexion angle. (iii) Design: The exoskeleton was designed with three working modes: rigid-support mode, elastic-support mode and follow mode. Rigid-support mode was suitable for scenes where the squatting posture is stable, while elastic-support mode was beneficial for working environments where the height of squatting varied frequently.The working environments were identified intelligently based on the EMGs of the gluteus maximus, and quadriceps, and the motor was controlled to switch the working mode between rigid-support mode and elastic-support mode. In follow mode, the exoskeleton moves freely with users without interfering with activities such as walking, ascending and descending stairs. (iv) Experiments: Three sets of experiments were conducted to evaluate the effect of exoskeleton. Experiment one was conducted to measure the surface electromyography signal (EMGs) in both condition of with and without exoskeleton, the root mean square of EMGs amplitude of soleus, vastus lateralis, vastus medialis, gastrocnemius, vastus intermedius, rectus femoris, gluteus maximus, and erector spinae were reduced by 98.5, 97.89, 80.09, 77.27, 96.73, 94.17, 70.71, and 36.32%, respectively, with the assistance of the exoskeleton. The purpose of experiment two was aimed to measure the plantar pressure with and without exoskeleton. With exoskeleton, the percentage of weight through subject's feet was reduced by 63.94, 64.52, and 65.61% respectively at 60°, 90°, and 120° of knee flexion angle, compared to the condition of without exoskeleton. Experiment three was purposed to measure the metabolic cost at a speed of 4 and 5 km/h with and without exoskeleton. Experiment results showed that the average additional metabolic cost introduced by exoskeleton was 2.525 and 2.85%. It indicated that the exoskeleton would not interfere with the movement of the wearer Seriously in follow mode. (v) Conclusion: The exoskeleton not only effectively reduced muscle fatigue, but also avoided interfering with the free movement of the wearer. [ABSTRACT FROM AUTHOR]

Dimethyl carbonate (DMC) was synthesized from methanol and ethylene carbonate (EC) in a reactive distillation column by transesterification using different composite oxide catalysts. The catalysts were characterized by XRD, N2 adsorption‐ desorption, CO2‐TPD, and NH3‐TPD. The results show that the Zr−Al catalyst has the most strong base sites and weak acid sites compared with other catalysts. The synergistic effect of acid‐base sites makes it show excellent catalytic performance for DMC synthesis. The operation parameters including reflux ratio, feed molar ratio, liquid hourly space velocity (LHSV) and catalyst dosage were optimized by factorial design based on response surface methodology (RSM). The best optimization conditions was: reflux ratio=5.23 : 1, feed molar ratio=6.05 : 1, LHSV=0.48 h−1, catalyst dosage=119.04 ml, the relative error between measured value and predicted value is small, which indicated that the reliability of the optimized process is high. [ABSTRACT FROM AUTHOR]

We synthesized polycyclosiloxanes with varying catechol substitution ratios (CFPSs) and investigated silver nanoparticles (AgNPs) adsorption ability on their self-assembled nanofilm. The nanoparticle adsorption ability as a function of the catechol substitution ratio was examined using SEM and a tape peeling test. It was evidenced that the substitution ratio of the catechol units was directly proportional to the surface density of AgNPs adsorbed on CFPS nanofilms. [ABSTRACT FROM AUTHOR]

In this decade, the demands of energy saving and diverse personal thermoregulation requirements along with the emergence of wearable electronics and smart textiles give rise to the resurgence of personal thermal management (PTM) technologies. PTM, including personal cooling, heating, insulation, and thermoregulation, are far more flexible and extensive than the traditional air/liquid cooling garments for the human body. Concomitantly, many new advanced materials and strategies have emerged in this decade, promoting the thermoregulation performance and the wearing comfort of PTM simultaneously. In this review, an overview is presented of the state‐of‐the‐art and the prospects in this burgeoning field. The emerging materials and strategies of PTM are introduced, and classed by their thermal functions. The concept of infrared‐transparent visible‐opaque fabric (ITVOF) is first highlighted, as it triggers the work on advanced PTM by combining it with radiative cooling, and the corresponding implementations and realizations are subsequently introduced, followed by wearable heaters, flexible thermoelectric devices, and sweat‐management Janus textiles. Finally, critical considerations on the challenges and opportunities of PTM are presented and future directions are identified, including thermally conductive polymers and fibers, physiological/psychological statistical analysis, and smart PTM strategies. [ABSTRACT FROM AUTHOR]

Reactive graphene oxide (GO) with multiple carboxyls or hydroxyls was well dispersed in a liquid silicon‐containing cycloaliphatic diepoxide. Upon heating the mixture gradually to 180°C, GO was in situ copolymerized with diepoxide to produce novel graphene/epoxy nanocomposites with the GO contents varied from 0 to 5 wt%. Fourier transform infrared spectra demonstrate that the reactive groups of GO have participated in the polymerization reaction. The composites thus obtained have similar amorphous wide‐angle X‐ray diffraction patterns to the pure epoxy resin, whereas the peak at 9.54° corresponding to GO aggregations is absent, indicating a homogeneous dispersion of GO within epoxy matrix, which is consistent with the scanning electron microscopy and transmission electron microscopy observations. The influence of the GO incorporation on dielectric properties, viscoelastic behaviors, glass transition temperatures, and thermal stability of GO/epoxy nanocomposites is systematically investigated by means of impedance analyzer, dynamic mechanical analysis, and thermal gravimetric analysis. The results show that the dielectric permittivities (k) of the samples significantly increase from 5.0 to 55 with the GO contents, and the k values are stable in the frequency range up to 1 MHz. The high dielectric permittivity and excellent dielectric stability are extremely important for the fabrication of high‐performance electronic devices. [ABSTRACT FROM AUTHOR]

The effect of the addition of different concentrations of Cu2+, Fe2+, and Fe3+ on the micromorphology and crystalline structure of CaCO3 fouling was studied using the VHX-500FE digital microscope and X-ray diffraction. Results indicate that the fouling morphology becomes stubby and forms a cluster and the fouling color deepens with the increase in the concentration of metal ions. Furthermore, the relative content of aragonite increases and that of calcite decreases. Fe2+ plays a more important role in the inhibition of calcite than Fe3+ when scaling occurs in the boiling system under the condition of atmospheric environment. The reason may be that O2 participates in the inhibition process. Fe2+ and Fe3+ promote atomic transition and crystal defects, and this condition changes the absorption wavelength of fouling. Carbon steel and copper samples were immersed in test solution for 28 h as a comparative experiment. This experiment indicates that corrosion may release metal ions, which further affect the fouling morphology and phase component content in the long-term fouling process. In conclusion, fouling weight method for measuring anti-fouling property can only be used to compare materials with similar anti-corrosion property. [ABSTRACT FROM AUTHOR]

With the advent of thermal metamaterials, many new thermal functionalities have been proposed, like thermal cloaking, concentrating, etc. However, these thermal functionalities are based on the transformation thermotics or scattering cancellation technique, which, derived from Fourier's law, cannot apply to the micro-/nanoscale counterparts. In this paper, we design a nanoscale thermal cloak based on a crystalline silicon (Si) membrane and investigate the in-plane phonon transport via non-equilibrium molecular dynamics (NEMD) simulation by in-situ tuning the thermal conductivity of the thermal cloak from crystalline Si to amorphous Si. The two-dimensional temperature profile is obtained, and the thermal cloaking effect is evaluated by the ratio of heat flux. By analyzing the phonon density of state (PDOS) and the mode participation ratio (MPR), the mechanism can be attributed to the phonon localization in the annealed cloaking region. The proposed nanoscale thermal cloak by in-situ tuned thermal conductivity, may trigger the development of nanoscale thermal functionalities and open avenues for and thermal management for nano-photonics and nano-electronics. • We design a nanoscale thermal cloak with in-site tuned thermal conductivity. • Thermal cloaking effect is positively proportional to the width of the cloak ring. • Phonon localization and non-propagating diffusive mode are attributed. [ABSTRACT FROM AUTHOR]

Inspired by the marine mussel strategy of adhesion in aqueous environments, catechol-functionalized polysiloxane (CFPS) was synthesized. Facile dip-coating showed good film forming ability on various organic and inorganic substrates with a surface roughness of 4.6 nm (50 μm × 50 μm). Silver nanoparticles (AgNPs) are anchored onto CFPS-modified substrates using a dip coating process. The scanning electron microscopy images revealed that AgNPs were distributed homogeneously on numerous substrates. Moreover, the surface number density and average interspace of the AgNPs were tuned easily by controlling the concentration of AgNP dispersions. A substrate with high-density AgNPs exhibited excellent surface enhanced Raman scattering (SERS) performance with an enhancement factor as high as 7.89 × 107 and an ultra-low detection limitation of 10−10 M, which can be ascribed to the “hotspots” formed between the adjacent AgNPs controlled by CFPS-induced self-assembly. The AgNP structures prepared on different substrates modified using CFPS show a similar high intensity, suggesting a versatile platform of the CFPS film for AgNP assemblies. In addition, AgNPs were anchored to be extremely stable on substrates because of strong hydrogen bonding interactions provided by the high surface-density catechol units of CFPS, which made the substrate a promising SERS sensor for practical applications. In situ SERS detection was also demonstrated on apple peel with no damage to AgNP structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simple surface treatment by steam improves adhesive bonding of aluminum remarkably. • High-resolution 3D imaging of the interfaces by STEM-tomography and STEM-EELS were performed for elucidate the mechanism. • Chemical interactions at aluminum/adhesive interfaces was proposed. A simple surface treatment by steam on aluminum substrate can enhance the bonding strength with epoxy adhesives. We studied the mechanism of the effect of steam on adhesive bonding by using scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS). The observed increase of adhesion strength was achieved by diffusion of the adhesive molecules into the nanopores of the aluminum surface, which switched the failure mode from interfacial failure to cohesive failure. Investigation of electron energy loss near edge fine structure (ELNES) in EELS allows us to find chemical bonding that form via acid–base interactions between the amino moiety of the adhesive and the hydroxyl groups on the aluminum surface. This weak bonding may not contribute directly to the increase of adhesion strength, but it induces spontaneous diffusion of the adhesion molecules into the pores via thermodynamically favored acid–base interfacial interactions. [ABSTRACT FROM AUTHOR]

The nano-scale failure behaviors of joint interfaces were investigated by in-situ straining technique to observe the crack propagations in a transmission electron microscope (TEM). The thin sections of bonded interfaces were subjected to tensile loading by using a specially designed specimen holder. The deformation at the crack tip before the initiation of crack and the initiation of the crack were observed in the nanometer level. The experiments with identical and dissimilar polymer/polymer welded specimens allowed us to see the plastic deformation ahead of the crack tip and the creation of craze, which is the typical failure mode of polymers. The failure of the interfaces between aluminum alloy (Al5052) and epoxy adhesive and between Al5052 and thermoplastic directly bonded by injection molding were investigated to visualize the failure behaviors in small scale before the macroscopic fracture of the interfaces. The in-situ straining technique under a high-resolution scanning transmission electron microscopy (STEM) mode enables the observation of micro deformation ahead of the crack, microvoids produced prior to the crack progression and the failure of the surface modified layer on Al surface. [ABSTRACT FROM AUTHOR]

Abstract: Fouling adhering experiments on AISI 304 stainless steel surfaces with different roughness had been performed in boiling supersaturated calcium bicarbonate solution. The effect of surface roughness on adhesion of fouling is limited, and the adhesion of fouling does not have a simple linear relationship with the surface roughness of samples. The surface with roughness in middle is more easily induced to form “transitional interface” which connects the fouling and matrix surface. It is also found that the crystalline types of fouling are changed in the fouling process due to the variation of metallic ions in reaction solution. [Copyright &y& Elsevier]

Exoskeleton robots are frequently applied to augment or assist the user's natural motion. Generally, each assisted joint corresponds to at least one specific motor to ensure the independence of movement between joints. This means that as there are more joints to be assisted, more motors are required, resulting in increasing robot weight, decreasing motor utilization, and weakening exoskeleton robot assistance efficiency. To solve this problem, the design and control of a lightweight soft exoskeleton that assists hip-plantar flexion of both legs in different phases during a gait cycle with only one motor is presented in this paper. Inspired by time-division multiplexing and the symmetry of walking motion, an actuation scheme that uses different time-periods of the same motor to transfer different forces to different joints is formulated. An automatic winding device is designed to dynamically change the loading path of the assistive force at different phases of the gait cycle. The system is designed to assist hip flexion and plantar flexion of both legs with only one motor, since there is no overlap between the hip flexion movement and the toe-offs movement of the separate legs during walking. The weight of the whole system is only 2.24 kg. PD iterative control is accomplished by an algorithm that utilizes IMUs attached on the thigh recognizing the maximum hip extension angle to characterize toe-offs indirectly, and two load cells to monitor the cable tension. In the study of six subjects, muscle fatigue of the rectus femoris, vastus lateralis, gastrocnemius and soleus decreased by an average of 14.69%, 6.66%, 17.71%, and 8.15%, respectively, compared to scenarios without an exoskeleton. [ABSTRACT FROM AUTHOR]

Wearable robotic devices have been proved to considerably reduce the energy expenditure of human walking. It is not only suitable for healthy people, but also for some patients who require rehabilitation exercises. However, in many cases, the weight of soft exosuits are relatively large, which makes it difficult for the assistant effect of the system to offset the metabolic consumption caused by the extra weight, and the heavy weight will make people uncomfortable. Therefore, reducing the weight of the whole system as much as possible and keeping the soft exosuit output power unchanged, may improve the comfort of users and further reduce the metabolic consumption. In this paper, we show that a novel lightweight soft exosuit which is currently the lightest among all known powered exoskeletons, which assists hip flexion. Indicated from the result of experiment, the novel lightweight soft exosuit reduces the metabolic consumption rate of wearers when walking on the treadmill at 5 km per hour by 11.52% compared with locomotion without the exosuit. Additionally, it can reduce more metabolic consumption than the hip extension assisted (HEA) and hip flexion assisted (HFA) soft exosuit which our team designed previously, which has a large weight. The muscle fatigue experiments show that using the lightweight soft exosuit can also reduce muscle fatigue by about 10.7%, 40.5% and 5.9% for rectus femoris, vastus lateralis and gastrocnemius respectively compared with locomotion without the exosuit. It is demonstrated that decreasing the weight of soft exosuit while maintaining the output almost unchanged can further reduce metabolic consumption and muscle fatigue, and appropriately improve the users' comfort. [ABSTRACT FROM AUTHOR]

To solve the complexity of the traditional motion intention recognition method using a multi-mode sensor signal and the lag of the recognition process, in this paper, an inertial sensor-based motion intention recognition method for a soft exoskeleton is proposed. Compared with traditional motion recognition, in addition to the classic five kinds of terrain, the recognition of transformed terrain is also added. In the mode acquisition, the sensors' data in the thigh and calf in different motion modes are collected. After a series of data preprocessing, such as data filtering and normalization, the sliding window is used to enhance the data, so that each frame of inertial measurement unit (IMU) data keeps the last half of the previous frame's historical information. Finally, we designed a deep convolution neural network which can learn to extract discriminant features from temporal gait period to classify different terrain. The experimental results show that the proposed method can recognize the pose of the soft exoskeleton in different terrain, including walking on flat ground, going up and downstairs, and up and down slopes. The recognition accuracy rate can reach 97.64%. In addition, the recognition delay of the conversion pattern, which is converted between the five modes, only accounts for 23.97% of a gait cycle. Finally, the oxygen consumption was measured by the wearable metabolic system (COSMED K5, The Metabolic Company, Rome, Italy), and compared with that without an identification method; the net metabolism was reduced by 5.79%. The method in this paper can greatly improve the control performance of the flexible lower extremity exoskeleton system and realize the natural and seamless state switching of the exoskeleton between multiple motion modes according to the human motion intention. [ABSTRACT FROM AUTHOR]

Walking on different terrains leads to different biomechanics, which motivates the development of exoskeletons for assisting on walking according to the type of a terrain. The design of a lightweight soft exoskeleton that simultaneously assists multiple joints in the lower limb is presented in this paper. It is used to assist both hip and knee joints in a single system, the assistance force is directly applied to the hip joint flexion and the knee joint extension, while indirectly to the hip extension also. Based on the biological torque of human walking at three different slopes, a novel strategy is developed to improve the performance of assistance. A parameter optimal iterative learning control (POILC) method is introduced to reduce the error generated due to the difference between the wearing position and the biological features of the different wearers. In order to obtain the metabolic rate, three subjects walked on a treadmill, for 10 min on each terrain, at a speed of 4 km/h under both conditions of wearing and not wearing the soft exoskeleton. Results showed that the metabolic rate was decreased with the increasing slope of the terrain. The reductions in the net metabolic rate in the experiments on the downhill, flat ground, and uphill were, respectively, 9.86 % , 12.48 % , and 22.08 % compared to the condition of not wearing the soft exoskeleton, where their corresponding absolute values were 0.28 W/kg, 0.72 W/kg, and 1.60 W/kg. [ABSTRACT FROM AUTHOR]

With the rapid development of microelectronic technology, increasing wearable devices are available for us in daily lives. These wearable devices are usually powered by batteries, so the endurance of wearable devices is limited by battery capacity. Biomechanical energy harvesting (EH) is a promising approach to extend the endurance or replace batteries to power microelectronic devices. In this paper, we would first review the different types of EH devices and analyze the key technologies. Secondly, to compare the advantages and disadvantages of different EH devices, the design guidelines of the EH device is proposed. According to the design guidelines, an EH device with a weight of only 110 g is designed, which is lighter than the suspended-load backpack (38 kg) and the knee harvester (1.6 kg). Our EH device is able to convert the vibrations energy generated by the motion of lower limbs into electrical energy. Finally, to verify whether our EH device meets the design guidelines, three sets of experiment are conducted to evaluate the performance of the EH device. Experiment A is used to monitor the metabolic energy and electricity energy. According to experiment data, we calculate the COH and TCOH of EH device. The lowest COH and TCOH are 58 and 59, respectively. The TCOH of our EH device is higher than suspended-load backpack (30.7) and the knee harvester (13.6). Experiment B is used to test the adaptability of the EH device under the different conditions of terrains and walking speeds. The EH device is able to harvest energy in different terrains (up and down stair, at the treadmill with a slope of 0 ° , 5 ° and 10 ° ) and at different speeds(4 km/h~8 km/h). The converted electrical power is up to 7.71 mW during walking at the speed of 8 km/h and is up to 5.28 mW when going up stairs. Experiment C is conducted to investigate the influence of the EH device on human motion by measuring the torque of the ankle, knee, and hip joints. When comparing the curves of torque, the EH device does not influence the biological moment of joints, indicating the EH device does not interfere with the movement. At the same time, another method to calculate the TCOH by calculating the net work done by the muscle in a gait cycle is proposed. When comparing the TCOH calculated by the metabolic energy with the TCOH calculated by the additional work done by the muscle, the results are basically the same. Meanwhile, the variation of the latter calculation result is smaller, indicating the method proposed by us is more precise. [ABSTRACT FROM AUTHOR]