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Energy management strategy is the essential approach for achieving high energy utilization efficiency of triboelectric nanogenerators (TENGs) due to their ultra-high intrinsic impedance. However, the proven management efficiency in practical applications remains low, and the output regulation functionality is still lacking. Herein, we propose a detailed energy transfer and extraction mechanism addressing voltage and charge losses caused by the crucial switches in energy management circuits. The energy conversion efficiency is increased by 8.5 times through synergistical optimization of TENG and switch configurations. Furthermore, a TENG-based power supply with energy storage and regularization functions is realized through system circuit design, demonstrating the stable powering electronic devices under irregular mechanical stimuli. A rotating TENG that only works for 21 s can make a hygrothermograph work stably for 417 s. Even under hand driving, various types of TENGs can consistently provide stable power to electronic devices such as calculators and mini-game consoles. This work provides an in-depth energy transfer and conversion mechanism between TENGs and energy management circuits, and also addresses the technical challenge in converting unstable mechanical energy into stable and usable electricity in the TENG field. Effective energy management is essential to enable triboelectric nanogenerators for realistic applications. Here, the authors optimize TENG and switch configurations to improve energy conversion efficiency and design a TENG-based power supply with energy storage and output regulation functionalities.

HighlightsA novel structure of the PC-TENG based on triboelectrification and electrostatic induction is designed.The PC-TENG produce ideal direct current output for driving small electronic devices directly even at low surface contact force.The novel PC-TENG owns a high durability and high output performance due to low wear of materials.The R-PC-TENG can efficiently harvest ambient mechanical energy.Triboelectric nanogenerator (TENG) is regarded as an effective strategy to convert environment mechanical energy into electricity to meet the distributed energy demand of large number of sensors in the Internet of Things (IoTs). Although TENG based on the coupling of triboelectrification and air-breakdown achieves a large direct current (DC) output, material abrasion is a bottleneck for its applications. Here, inspired by primary cell and its DC signal output characteristics, we propose a novel primary cell structure TENG (PC-TENG) based on contact electrification and electrostatic induction, which has multiple working modes, including contact separation mode, freestanding mode and rotation mode. The PC-TENG produces DC output and operates at low surface contact force. It has an ideal effective charge density (1.02 mC m−2). Meanwhile, the PC-TENG shows a superior durability with 99% initial output after 100,000 operating cycles. Due to its excellent output performance and durability, a variety of commercial electronic devices are powered by PC-TENG via harvesting wind energy. This work offers a facile and ideal scheme for enhancing the electrical output performance of DC-TENG at low surface contact force and shows a great potential for the energy harvesting applications in IoTs.

Triboelectric nanogenerator (TENG) is a promising strategy for harvesting low frequency mechanical energy. However, the bottlenecks of limited electric output by air/dielectric breakdown and poor durability by material abrasion seriously restrict its further improvement. Herein, we propose a liquid lubrication promoted sliding mode TENG to address both issues. Liquid lubrication greatly reduces interface material abrasion, and its high breakdown strength and charge transmission effect further enhance device charge density. Besides, the potential decentralization design by the voltage balance bar effectively suppresses the dielectric breakdown. In this way, the average power density up to 87.26 W·m-2·Hz-1, energy conversion efficiency of 48%, and retention output of 90% after 500,000 operation cycles are achieved, which is the highest average power density and durability currently. Finally, a cell phone is charged to turn on by a palm-sized TENG device at 2 Hz within 25 s. This work has a significance for the commercialization of TENG-based self-powered systems.

Direct current triboelectric nanogenerators (DC-TENGs) are a groundbreaking technology to capture micromechanical energy from the natural environment, which is crucial for directly powering sensor networks. However, the research bottleneck in enhancing the triboelectric electrification capability and charge storage capability of dielectrics has hindered the overall performance breakthroughs of the DC-TENG. Here, a field emission model-based DC-TENG (FEM-TENG) is proposed, inspired by lightning rods. The enhanced local electric field between dielectric materials and electrodes induces strong electron tunneling, which improves charge neutralization on the surface of materials and their internal charge storage space, thereby utilizing the dielectric volume effect effectively and strengthening triboelectricity. Guided by the field emission model, the FEM-TENG with a historic crest factor of 1.00375 achieves a groundbreaking record of an average power density of 16.061 W m −2 Hz −1 (1,591 W m −3 Hz −1 ), which is 5.36-fold of the latest DC-TENG. In particular, the FEM-TENG with high durability (100%) truly realizes the collection of breeze energy and continuously drives 50 thermohygrometers. Four additional applications exemplify the FEM-TENG, enabling comprehensive sensing of land, water, and air. This work proposes a paradigm strategy for the in-depth utilization of dielectric films, aiming to enhance the output power of DC-TENGs.

Triboelectric nanogenerator (TENG) is a new cost-effective blue energy harvesting technology for its great performance in low frequency. However, many related energy harvesters operate on water surface, ignoring the ocean’s depth. Herein, a chain-flipped plate TENG (CFP-TENG), consisting of longitudinally arranged repeating units, is proposed to collect wave energy. The chain structure design allows the surface wave energy to act effectively on the underwater generator. The maximum output power per unit ocean area reaches 1.5 W·m −2 at a loading resistance of 30 MΩ. Optimization of device parameters and application demonstrations are explored. Compared with previous works, the utilization rate of wave energy has been significantly improved. This work not only provides a new method to optimize the output of TENG but also makes a crucial step in promoting practical applications of TENG in renewable blue energy.

The triboelectric nanogenerator (TENG) has been considered a low-frequency mechanical energy collection and conversion device in the modern era. The reasonable stack structure of TENG is an effective method to boost its electric output performance within a limited space. Nevertheless, relying solely on the stacking structure, the TENG is unable to produce excessive output due to the low contact electrification capability of its materials. Hence, there are still significant challenges in enhancing the output performance of stacked TENGs. We propose a multi-layer-stack TENG (M-TENG) with two zigzag-shaped (Z-shaped) multilayer units interleaving and stacking with each other, which enormously enlarges the effective utilization area. Furthermore, a voltage multiplier circuit (VMC) incorporating a Zener diode allows the transfer charge to approach the critical threshold and maintain a stable output. The transfer charge and current of M-TENG integrated with a VMC can reach 1.52 μC and 86 μA, respectively, with the maximum output of the TENG being 8.65 mW (5 MΩ). To prove it as a self-power device, M-TENG excited by a VMC is employed to power 912 light-emitting diodes (LEDs) and three temperature and humidity sensors with a power management circuit (PMC), respectively. This work offers a new method for optimizing stacking-layer TENG electric output performance in a narrow space.

Sophora moorcroftiana, a Leguminosae shrub species that is restricted to the arid and semi-arid regions of the Qinghai-Tibet Plateau, is an ecologically important foundation species and exhibits substantial drought tolerance in the Plateau. There are no functional genomics resources in public databases for understanding the molecular mechanism underlying the drought tolerance of S. moorcroftiana. Therefore, we performed a large-scale transcriptome sequencing of this species under drought stress using the Illumina sequencing technology. A total of 62,348,602 clean reads were obtained. The assembly of the clean reads resulted in 146,943 transcripts, including 66,026 unigenes. In the assembled sequences, 1534 transcription factors were identified and classified into 23 different common families, and 9040 SSR loci, from di- to hexa-nucleotides, whose repeat number is greater than five, were presented. In addition, we performed a gene expression profiling analysis upon dehydration treatment. The results indicated significant differences in the gene expression profiles among the control, mild stress and severe stress. In total, 4687, 5648 and 5735 genes were identified from the comparison of mild versus control, severe versus control and severe versus mild stress, respectively. Based on the differentially expressed genes, a Gene Ontology annotation analysis indicated many dehydration-relevant categories, including 'response to water 'stimulus' and 'response to water deprivation'. Meanwhile, the Kyoto Encyclopedia of Genes and Genomes pathway analysis uncovered some important pathways, such as 'metabolic pathways' and 'plant hormone signal transduction'. In addition, the expression patterns of 25 putative genes that are involved in drought tolerance resulting from quantitative real-time PCR were consistent with their transcript abundance changes as identified by RNA-seq. The globally sequenced genes covered a considerable proportion of the S. moorcroftiana transcriptome, and the expression results may be useful to further extend the knowledge on the drought tolerance of this plant species that survives under Plateau conditions.

Background: A previous study has shown that 81% of the COVID-19 patients had mild or moderate symptoms. However, most studies on the sequelae in COVID-19 patients focused on severe cases and the long-term follow-up studies on the health consequences in non-severe cases are limited. The current study aimed to assess the sequelae of COVID-19 in patients nearly 1 year after diagnosis with a particular focus on the recovery of patients with non-severe COVID-19. Methods: We enrolled 120 patients infected with SARS-CoV-2 discharged from Wuhan Union hospital west district (designated hospital for COVID-19) and Fangcang shelter hospitals between January 29, 2020 and April 1, 2020. All participants were asked to complete a series of questionnaires to assess their symptoms and quality of life and for psychological evaluation. Also, pulmonary function test, chest CT, 6-min walking test (6MWT), routine blood test, liver and kidney function tests, fasting blood glucose test, lipid test, and immunoglobulin G antibody test were performed to evaluate their health. Results: The mean age of the study population was 51.6 ± 10.8 years. Of the 120 patients, 104 (86.7%) were cases of non-severe COVID-19. The follow-up study was performed between November 23, 2020 and January 11, 2021, and the median time between the diagnosis and the follow-up was 314.5 (IQR, 296–338) days. Sleep difficulties, shortness of breath, fatigue, and joint pain were common symptoms observed during follow-up and nearly one-third of the non-severe cases had these symptoms. A total of 50 (41.7%) and 45 (37.5%) patients reported anxiety and depression, respectively. And 18.3% of the patients showed negative results in the IgG test at the follow-up, which correlated with the severity of the infection ( R = 0.203, p = 0.026), and the proportion of IgG negative cases in non-severe COVID-19 patients was higher than that in the severe cases (20.2 vs. 6.3%). Pulmonary diffusion impairment was reported in 30 (26.1%) out of 115 patients, and 24 (24.2%) out of the 99 non-severe cases. The values of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FVC/FEV1, vital capacity (VC), total lung capacity (TLC), and residual volume (RV) were less than the normal range in 1.7, 8.6, 0.9, 11.2, 7.0, and 0.9% of the patients, respectively. A total of 55 (56.7%) out of the 97 patients showed abnormal CT findings, including ground-glass opacities (GGO), bronchiectasis, nodules, lines and bands, and fibrosis. Furthermore, there was a correlation between all the SF-36-domain scores and the duration of hospitalization, pulmonary function, and a 6MWT. Conclusions: At the nearly 1-year follow-up, COVID-19 survivors still had multi-system issues, including those in the respiratory functioning, radiography, quality of life, and anxiety and depression. Moreover, non-severe cases also showed some sequelae and the proportion of IgG negative cases in the non-severe patients was higher than that in severe cases. Therefore, conducting follow-ups and preventing the reinfection of SARS-CoV-2 in this group is necessary.

Abstract Context Age of pubertal onset has been decreasing in many countries but there have been no data on pubertal development in Chinese children over the last decade. Objective The primary objective of the study was to evaluate the current status of sexual maturation in Chinese children and adolescents. Secondary objectives were to examine socioeconomic, lifestyle, and auxological associations with pubertal onset. Methods In this national, cross-sectional, community-based health survey, a multistage, stratified cluster random sampling method was used to select a nationally representative sample, consisting of 231 575 children and adolescents (123 232 boys and 108 343 girls) between 2017 and 2019. Growth parameters and pubertal staging were assessed by physical examination. Results Compared to 10 years previously, the median age of Tanner 2 breast development and menarche were similar at 9.65 years and 12.39 years respectively. However, male puberty occurred earlier with a median age of testicular volume ≥4 mL of 10.65 years. Pubertal onset did occur earlier at the extremes, with 3.3% of the girls with breast development at 6.5-6.99 years old, increasing to 5.8% by 7.5-7.99 years old. Early pubertal onset was also noted in boys, with a testicular volume ≥ 4 mL noted in 1.5% at 7.5-7.99 years, increasing to 3.5% at 8.5-8.99 years old. Obesity and overweight increased risk of developing earlier puberty relative to normal weight in both boys and girls. Conclusion Over the past decade, pubertal development is occurring earlier in Chinese children. While the cause is multifactorial, overweight and obesity are associated with earlier puberty onset. The currently used normative pubertal data of precocious puberty may not be applicable to diagnose precocious puberty.

Background Growth chart is a valuable clinical tool to monitor the growth and nutritional status of children. A growth chart widely used in China is based on the merged data sets of national surveys in 2005. We aimed to establish an up-to-date, complete growth curve for urban Chinese children and adolescents with a full range of ages. Methods Using data collected in a large-scale, cross-sectional study (Prevalence and Risk factors for Obesity and Diabetes in Youth (PRODY), 2017–2019), we analyzed 201,098 urban children aged 3 to 18 years from 11 provinces, autonomous regions, and municipalities that are geographically representative of China. All participants underwent physical examinations. Sex-specific percentiles of height-for-age and weight-for-age were constructed by Generalized Additive Models for Location Scale and Shape (GAMLSS) model. We also compared the median values of height-for-age or weight-for-age between our growth chart and the established growth reference using Welch-Satterthwaite T-Test. Results Consistent with the established growth reference, we observed that the P 50 percentile of height-for-age reached plateaus at the age of 15 years (172 cm) and 14 years (160 cm) for boys and girls, respectively. In addition, boys aged 10 ~ 14 years and girls aged 10 ~ 12 years exhibited the most dramatic weight difference compared to those of other age groups (19.5 kg and 10.3 kg, respectively). However, our growth chart had higher median values of weight-for-age and height-for-age than the established growth reference with mean increases in weight-for-age of 1.36 kg and 1.17 kg for boys and girls, respectively, and in height-for-age of 2.9 cm and 2.6 cm for boys and girls, respectively. Conclusions Our updated growth chart can serve as a reliable reference to assess the growth and nutritional status in urban Chinese children throughout the entire childhood.