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To achieve large-scale development of triboelectric nanogenerators (TENGs) for water wave energy harvesting and powering the colossal sensors widely distributed in the ocean, facile and scalable TENGs with high output are urgently required. Here, an elastic self-recovering hybrid nanogenerator (ES-HNG) is proposed for water wave energy harvesting and marine environmental monitoring. The elastic skeletal support of the ES-HNG is manufactured using three-dimensional (3D) printing technology, which is more conducive to the large-scale integration of the ES-HNG. Moreover, the combination of a TENG and an electromagnetic generator (EMG) optimizes the utilization of device space, leading to enhanced energy harvesting efficiency. Experimental results demonstrate that the TENG achieves a peak power output of 42.68 mW, and the EMG reaches a peak power output of 4.40 mW. Furthermore, various marine environment monitoring sensors, such as a self-powered wireless meteorological monitoring system, a wireless alarm system, and a water quality monitoring pen, have been successfully powered by the sophisticated ES-HNG. This work introduces an ES-HNG for water wave energy harvesting, which demonstrates potential in marine environment monitoring and offers a new solution for the sustainable development of the marine internet of things. [ABSTRACT FROM AUTHOR]

After more than five decades, Moore's Law for transistors is approaching the end of the international technology roadmap of semiconductors (ITRS). The fate of complementary metal oxide semiconductor (CMOS) architecture has become increasingly unknown. In this era, 3D transistors in the form of gate-all-around (GAA) transistors are being considered as an excellent solution to scaling down beyond the 5 nm technology node, which solves the difficulties of carrier transport in the channel region which are mainly rooted in short channel effects (SCEs). In parallel to Moore, during the last two decades, transistors with a fully depleted SOI (FDSOI) design have also been processed for low-power electronics. Among all the possible designs, there are also tunneling field-effect transistors (TFETs), which offer very low power consumption and decent electrical characteristics. This review article presents new transistor designs, along with the integration of electronics and photonics, simulation methods, and continuation of CMOS process technology to the 5 nm technology node and beyond. The content highlights the innovative methods, challenges, and difficulties in device processing and design, as well as how to apply suitable metrology techniques as a tool to find out the imperfections and lattice distortions, strain status, and composition in the device structures. [ABSTRACT FROM AUTHOR]

Thinning plays a vital role in controlling stand density of plantation forests to get quality wood and more ecological function. However, the specific effects of thinning on forest biomass connected with forest age are usually overlooked especially in semi-arid regions. Here, we examined the effects of thinning on individual tree growth and stand biomass in a chronosequence of 20-, 30-, 40-, and 50-year-old Chinese pine (Pinus tabulaeformis) plantations on the Loess Plateau, China. We found that under different thinning managements, both mean diameter at breast height (DBH) and tree height followed the logistic growth pattern, and thinning promoted tree radial growth more than height. The effects of thinning on tree biomass differed between the individual tree and stand level. Thinning could promote individual tree biomass irrespective of stand ages, while stand biomass did not differ between the thinned and unthinned stands at different stand ages. Furthermore, the multiple linear regression analysis and structure equation model showed that individual tree growth was the primary contributor of stand biomass. Thus, we infer that the stand biomass loss after thinning could be mainly compensated by enhanced tree growth, especially radial growth, after a period of recovery (no more than 20 years). The results could provide helpful guidance for forest management and highlighted that reasonable thinning treatment could result in both high individual tree product and stand level harvests in the long term. [ABSTRACT FROM AUTHOR]

The exposure of recycled concrete (RCA) to a sulphate environment in cold regions makes it crucial to overcome the freeze–thaw cycling effects of recycled concrete. Based on steel and basalt fiber reinforced recycled concrete, the freeze–thaw cycle resistance of recycled concrete was studied by exposure to a sulphate environment. The mass loss, dynamic elastic modulus loss and compressive strength loss of the specimens were studied through freeze–thaw cycle experiments. SEM techniques were used to explore the effect of fiber distribution on the freeze–thaw resistance of recycled concrete. The freeze–thaw mechanism of the basalt fiber and steel fiber recycled concrete exposed to a sulphate environment has also been summarized. The results show that, based on the sulphate environment, the composite fiber recycled concrete has a higher stability in terms of mass loss and relative dynamic modulus of elasticity than single fiber concrete. The compressive strength of S0.9RC (recycled concrete with 0.9% steel fibers) and BF5.5RC (recycled concrete containing 5.5 kg/m3 basalt fibers) increased by 8.62% and 13.62%, respectively, compared to normal recycled concrete after 28 days of maintenance; and after 150 freeze–thaw cycles, the compressive strength increased by 41.39% and 47.54%, respectively; compared to ordinary natural aggregate concrete, the compressive strength of S0.9RC and BF5.5RC increased by 32.90% and 27.36%, respectively. The compressive strength of the S1.5BF7.5RC (recycled concrete with 1.5% steel fibers and 7.5 kg/m3 basalt fibers) composite basalt fiber–steel fiber concrete also increased by 42.82%. SEM techniques indicated that the basalt fiber in the recycled concrete exhibited fracture damage, which inhibited the development of microcracks within the concrete. When the recycled concrete is subjected to coupled sulphate and freeze–thaw cycles, freezing occurs from the outside in, with ice crystals extending along the cracks into the matrix. Prior to freezing, a negative pressure is created by the compression of the air and the contraction of the salt solution, which pulls the external solution inwards. The brine is in a state where ice and water coexist during the continuous cooling process. The salt solution migrates from the inside to the outside during heating and melting. [ABSTRACT FROM AUTHOR]

Carbon fiber (CF) reinforced composites are widely used due to their excellent properties. However, the smooth surface and few functional groups of CFs can lead to fiber fractures and pullout, which reduce the service life of the composites. The overall performance of composites can be improved by growing carbon nanotubes (CNTs) on the CF surface. Before this, CF surface should be modified to enhance the loading amount of catalyst particles and thus make the CNTs more uniform. In this paper, CNTs were grown on a CF surface by one-step chemical vapor deposition to prepare multi-scale CNTs/CF reinforcements, and the effects of different methods on the CF surface modification were explored. After setting four intensities of electrochemical anodic oxidation, i.e., 50 C/g, 100 C/g, 150 C/g and 200 C/g, it was found that the distribution and quantity of CNTs were improved under both the 100 C/g and 150 C/g conditions. Considering the influence of electrical intensity on the (002) interplanar spacing of CFs, which affects the mechanical properties of the samples, 100 C/g was finally selected as the optimal electrochemical treatment intensity. This finding provides a reference for continuous and large-scale modification of CF surfaces to prepare CNTs/CF multi-scale reinforcements. [ABSTRACT FROM AUTHOR]

Carbon fiber composites as pantograph slide materials are in the development stage, in which copper is the conductive phase, and the addition form and size need to be designed. Herein, the effects of the copper morphology, the size of the copper mesh on the performance, and the influence of the contact mode between the sliding plate and bracket on the temperature rise were compared and analyzed. The resistivity is 11.2 μΩ·m with the addition of 20 wt% copper mesh, a relative reduction of 91.77%. Importantly, the impact strength is increased by 14.19%, and the wear is reduced by 13.21%; hence, the copper mesh laid in layers is the ideal structure. Further study of the distribution and quality of the copper mesh shows that the resistivity is related only to the quality of the copper mesh; in addition, the number of layers of the copper mesh cannot exceed 16, and it is determined that the best type of copper mesh is 5#. Notably, the performance can be improved by appropriately reducing the thickness of the copper mesh and increasing the aperture while the sliding plate and the bracket are connected by copper mesh with conductive adhesive, which has the slowest heating rate of 2.27 °C/min and the smallest resistance. Therefore, the influence of copper content and distribution on the electrical conductivity are systematically investigated, and the mechanical properties and electrical conductivity are optimized through the design of the laminate structure of the compound material. [ABSTRACT FROM AUTHOR]

Different from systems that directly provide online shared courses such as MOOC, online learning systems such as Tencent Classroom simulate a real classroom environment for students and teachers to realize online face-to-face teaching, utilized during the COVID-19 pandemic. Nevertheless, due to the limitation of physical distance, the intelligent design of online learning systems is necessary to provide students with a good learning experience. This study notes that an unexpected optimization effect is the impact of system characteristics on the flow experience of online learning systems, which has not been studied, but plays a vital role in the effectiveness of online learning systems. In the study, a questionnaire was created and multi-stage sampling was used to investigate 623 college students. Based on the DeLone and McLean model of IS success and flow theory, a model for optimizing system characteristics and flow experience was constructed and its effectiveness was tested. The results reveal that system characteristics have a positive impact on continuance intention and flow experience. Additionally, flow experience and learning effect have a positive impact on continuance intention. Furthermore, flow experience has a positive impact on the learning effect. This study emphasizes the flow experience of online learning systems and reveals the optimization direction of online virtual face-to-face classrooms to provide references for the Ministry of Education, schools, and enterprises providing education systems. [ABSTRACT FROM AUTHOR]

Overtaking behavior between non-motorized vehicles is one of the main characteristics of the cycling path, and unsafe overtaking behavior has a certain negative impact on riders' safety. However, little is known about the factors affecting riders' overtaking decisions. This study aimed to identify the influence of road facilities, types of non-motorized vehicles, and human factors on the characteristics of overtaking behavior on bicycle lanes. DJI drone-based naturalistic riding research was explored in China and a random parameter logit regression model was estimated to model the overtaking decisions of non-motorized vehicle riders. The results showed that gender, age, professional deliverer, type of lead non-motor vehicle, type of non-motorized vehicles, and width of cycling lane influence overtaking behavior significantly. The present study provides theoretical evidence to strengthen the safety design and evaluation of cycling lane infrastructure. [ABSTRACT FROM AUTHOR]

The ultraviolet–visible imaging spectropolarimeter (UVISP), developed by the Anhui Institute of Optics and Fine Mechanics (AIOFM), Chinese Academy of Science (CAS), is a dual-beam snapshot instrument for measuring the spectral, radiometric, and linear polarization information of absorbing aerosol in a wavelength range from 340 to 520 nm. In this paper, we propose a complete set of calibration methods for UVISP to ensure the accuracy of the measured radiation polarization data, thus guaranteeing the reliability of inversion results. In geometric calibration, we complete the assignment of the field of view (FOV) angle to each pixel of the detector using a high precision turntable and parallel light source. In addition, the geometric calibration accuracy of the S beam and P beam is also analyzed. The results show that the residuals of all row pixels are less than 0.12°. Based on geometric calibration, a spectral calibration is conducted at each spectrum of the S beam and P beam for the given FOV, and the relation between the wavelength and pixel is obtained by a linear fitting procedure. For radiometric calibration, the uniformity of spectral responsivity is corrected, and the function between spectral radiance and output digital data is established. To improve the accuracy of the polarimetric measurement, a polarimetric calibration is proposed, and validated experimental results show that the root mean square (RMS) errors for the demodulated value are all within 0.011 for the input linear polarized light with different angles of linear polarization (AoLPs). Finally, field measurements are conducted, and the absolute deviations are all within 0.01 when the UVISP and CE-318 sun–sky polarimetric radiometer (CE318N) simultaneously measure the degree of linear polarization (DoLP) of the sky at different zenith angles. These experimental results demonstrate the efficiency and accuracy of the proposed calibration methods. [ABSTRACT FROM AUTHOR]

The addition of graphene oxide (GO) and fly ash (FA) to SFRC (steel fiber reinforced concrete) increases frost resistance. Based on the analysis of the amelioration of GO on the frost resistance of SFRC, the improvement mechanism and the effects of GO and FA on the durability of SFRC were studied in depth. The test blocks' compressive strength, relative dynamic modulus of elasticity, and mass-loss rate were tested through experiments. The pore distribution and morphological characteristics of concrete were captured by industrial CT scanning technology. The effects of GO and FA on the pore distribution and morphology of the SFRC are discussed. The results show that the compressive strength of GO-SFRC(graphene oxide and steel fiber reinforced concrete)with GO proportion of 0.03% is 28.20% higher than that of ordinary SFRC without freezing and thawing; after 100 freeze-thaw cycles, the compressive strength of the G0.03S25 increased by 31.70% compared with the compressive strength of the G0.00S25, and pore shape of G0.03S25 presents a spherical shape and an elliptical spherical shape; based on the data analysis of the strength loss, relative dynamic elastic modulus loss and mass-loss rate, it is considered that the properties of ordinary SFRC are the worst under freezing and thawing; as FA admixture increases, the porosity decreases; with FA of 30% and GO of 0.03%, the GO-FA-SFRC has the best frost resistance, as well as most of the pores are closed which resemble spheres and ellipsoids. [ABSTRACT FROM AUTHOR]

Poyang lake floodplains are hydrologically complex and dynamic systems which exhibit dramatic intra-annual wetting and drying. The flow regime of the Yangtze River was previously known to play an important role in affecting Poyang Lake and its extremely productive floodplains (river–lake relationship). The recent severe declines and recessions in the lake are closely linked to the changed river–lake relationship, resulting in significant hydrological, ecological, and economic problems. This study aims to examine the spatiotemporal heterogeneity of the floodplain hydrodynamic behaviors with respect to impacts of the changed river–lake relationship, characterized by the lake water level, inundation area, and inundation duration based on a floodplain hydrodynamic model of Poyang Lake, and to further quantify the severity of dryness recently endured since 2000. Simulation results show that, in general, the current modified river–lake relationship is more likely to affect the hydrological seasonality of the floodplain system since 2000, relative to the flooding and drying cycles during past decades (1953–2000). The present hydrodynamic behaviors suffered significant change due to the greatest interference from the altered river–lake relationship, particularly for the falling period in October. On average, the floodplain water level and inundation duration decreased by 6 m and 12 days during October, respectively. Additionally, the highest monthly shrinkage rate in floodplain inundation shifted from the period of October–November to September–October, with the mean inundation area decreasing by around 50%, demonstrating an advanced and prolonged dry condition. The spatial responses of the hydrodynamics in the low-slope floodplains are most likely to be affected by the dynamic river–lake relationship, as expected. This study assessed the effects of the altered river–lake relationship on the hydrological regime of the Poyang Lake floodplains in terms of spatiotemporal distributions and changing processes for the periodic inundated behavior, which can support the relevant study of the subsequent ecological effects on the wetlands. [ABSTRACT FROM AUTHOR]

The performance of the event-related potential (ERP)-based brain–computer interface (BCI) declines when applying it into the real environment, which limits the generality of the BCI. The sound is a common noise in daily life, and whether it has influence on this decline is unknown. This study designs a visual-auditory BCI task that requires the subject to focus on the visual interface to output commands and simultaneously count number according to an auditory story. The story is played at three speeds to cause different workloads. Data collected under the same or different workloads are used to train and test classifiers. The results show that when the speed of playing the story increases, the amplitudes of P300 and N200 potentials decrease by 0.86 μV (p = 0.0239) and 0.69 μV (p = 0.0158) in occipital-parietal area, leading to a 5.95% decline (p = 0.0101) of accuracy and 9.53 bits/min decline (p = 0.0416) of information transfer rate. The classifier that is trained by the high workload data achieves higher accuracy than the one trained by the low workload if using the high workload data to test the performance. The result indicates that the sound could affect the visual ERP-BCI by increasing the workload. The large similarity of the training data and testing data is as important as the amplitudes of the ERP on obtaining high performance, which gives us an insight on how make to the ERP-BCI generalized. [ABSTRACT FROM AUTHOR]