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197 results on '"Xu, Yunhe"'

9. Bioinspired Wearable Thermoelectric Device Constructed with Soft‐Rigid Assembly for Personal Thermal Management.

Author

Wu, Bo, Lin, Yujie, Tian, Yuqing, Wei, Wei, Xu, Yunhe, Hu, Yunhao, Li, Jianmin, Li, Kerui, Hou, Chengyi, Zhang, Qinghong, Li, Yaogang, and Wang, Hongzhi

Subjects
THERMOELECTRIC apparatus & appliances, HEAT convection, HEAT transfer, BODY temperature, FLEXIBLE structures
Abstract

The development of high‐performance thermoelectric devices (TEDs) with personal thermoregulation is crucial for the advancement of next‐generation wearable technologies. Most efforts focus on optimizing mechanical flexibility in fully encapsulated devices, but parasitic heat loss induced by the layer‐packed polymer matrices with high thermal impedance typically leads to degradation in sensing and bidirectional conversion capabilities. Here, a bioinspired architectural strategy is proposed for this problem that demonstrates the feasibility of single‐sided assembly based on a soft‐rigid "skin‐spine" configuration to improve heat utilization efficiency. With active TE units connected via serpentine electrodes, skin‐spine‐structured wearable thermoelectric devices (SSSW‐TEDs) are successfully fabricated enabling temperature sensing and bidirectional heat‐to‐electricity conversion under mild forced convection. This contributes to significant enhancements in power delivery (by 300%) and cost‐benefit analysis (by 100%) through efficient air convection heat dissipation. Moreover, SSSW‐TED enables personal thermal regulation by harnessing body heat, cooling the skin, and perceiving behaviors such as touching and blowing. This study not only provides novel insights for high‐performance TEDs but also lays the foundation for the widespread implementation of skin thermoregulation. [ABSTRACT FROM AUTHOR]

Published
2024
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16. High Thermoelectric Performance in Ti3C2Tx MXene/Sb2Te3 Composite Film for Highly Flexible Thermoelectric Devices.

Author

Xu, Yunhe, Wu, Bo, Hou, Chengyi, Li, Yaogang, Wang, Hongzhi, and Zhang, Qinghong

Subjects
THERMOELECTRIC apparatus & appliances, THERMOELECTRIC materials, POWER resources, ELECTRIC conductivity, HYDROTHERMAL synthesis
Abstract

Flexible thin‐film thermoelectric devices (TEDs) can generate electricity from the heat emitted by the human body, which holds great promise for use in energy supply and biomonitoring technologies. The p‐type Sb2Te3 hexagon nanosheets are prepared by the hydrothermal synthesis method and compounded with Ti3C2Tx to make composite films, and the results show that the Ti3C2Tx content has a significant impact on the thermoelectric properties of the composite films. When the Ti3C2Tx content is 2 wt%, the power factor of the composite film reaches ≈59 µW m−1 K−2. Due to the outstanding electrical conductivity, high specific surface area, and excellent flexibility of Ti3C2Tx, the composite films also exhibit excellent thermoelectric and mechanical properties. Moreover, the small addition of Ti3C2Tx has a negligible effect on the phase composition of Sb2Te3 films. The TED consists of seven legs with an output voltage of 45 mV at ΔT = 30 K. The potential of highly flexible thin film TEDs for wearable energy collecting and sensing is great. [ABSTRACT FROM AUTHOR]

Published
2024
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18. Joint Beamforming and Reflecting Elements Optimization for Segmented RIS Assisted Multi-User Wireless Networks

Author

Wang, Xiaoqing, Zheng, Rui, Du, Fei, Zhao, Xiongwen, Zhang, Yu, Xu, Yunhe, Geng, Suiyan, and Qin, Peng

Abstract

The emerging reconfigurable intelligent surface (RIS) is a prospective technique to modulate the wireless channel and improve performance, in which large amounts of passive elements manipulate independently, inevitably resulting in a high-dimensional optimization problem that is intractable to solve. With the aim to strike a balance between optimality and complexity for RIS assisted multi-user systems, in this article, we formulate the achievable sum rate maximization problem under a novel RIS segmentation structure, where the distributions and sizes of each segmentation can be adaptively adjusted. Since the formulated optimization problem considering the quality of service (QoS) requirements for the users is non-convex, we suggest a computationally-efficient approach to derive an optimal solution by exploiting fractional programming, successive convex approximation (SCA), greedy algorithm, and alternating optimization. Finally, numerical simulations reveal that the proposed optimization design enables RIS to configure by grouping elements into some sub-surfaces without significant performance degradation while with much lower computational complexity than conventional element-wise optimization RIS. Moreover, our proposed adjustable segmentation outperforms the fixed one employing the determined positions and equal number of reflecting elements in each sub-surface. Additionally, the results demonstrate that the optimization of segmentation is much more significant than the phase shift optimization, showing the superiority and practical significance of the sub-surface segmentation strategy.

Published
2024
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32. Effective Heuristic Techniques for Combined Robust Clustering Problem.

Author

Xu, Yunhe, Wu, Chenchen, Gai, Ling, and Han, Lu

Subjects
APPROXIMATION algorithms, HEURISTIC algorithms, NP-hard problems, HEURISTIC, DATA mining
Abstract

Clustering is one of the most important problems in the fields of data mining, machine learning, and biological population division, etc. Moreover, robust variant for k -means problem, which includes k -means with penalties and k -means with outliers, is also an active research branch. Most of these problems are NP-hard even the most classical problem, k -means problem. For the NP-hard problems, the heuristic algorithm is a powerful method. When the quality of the output can be guaranteed, the algorithm is called an approximation algorithm. In this paper, combining two types of robust settings, we consider k -means problem with penalties and outliers (k -MPO). In the k -MPO, we are given an n -point set U ⊂ ℝ d , a penalty cost p v ≥ 0 for each v ∈ U , an integer k ≤ n , and an integer z ≤ n. The target is to find a center subset S ⊆ ℝ d with | S | ≤ k , a penalty subset P ⊆ U and an outlier subset Z ⊆ U with | Z | ≤ z , such that the sum of the total costs, including the connection cost and the penalty cost, is minimized. We offer an approximation algorithm using a heuristic local search scheme. Based on a single-swap manipulation, we obtain 2 7 4 -approximation algorithm. [ABSTRACT FROM AUTHOR]

Published
2023
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43. Serum C-reactive protein increases the risk of venous thromboembolism: a prospective study and meta-analysis of published prospective evidence

Author

Kunutsor, Setor, Blom, Ashley, Xu, Yunhe, Seidu, Samuel, Khunti, Kamlesh, and Laukkanen, Jari

Subjects
Adult, Male, medicine.medical_specialty, Epidemiology, Regression dilution, Population, 030204 cardiovascular system & hematology, deep vein thrombosis, C-reactive protein, Body Mass Index, 03 medical and health sciences, 0302 clinical medicine, Risk Factors, Internal medicine, Deep vein thrombosis, Medicine, Humans, 030212 general & internal medicine, cardiovascular diseases, Prospective Studies, Prospective cohort study, education, Cohort Study, education.field_of_study, biology, business.industry, Proportional hazards model, Hazard ratio, Pulmonary embolism, Venous Thromboembolism, Middle Aged, Confidence interval, Surgery, Centre for Surgical Research, biology.protein, Regression Analysis, Female, C- reactive protein, business, Cohort study, Biomarkers, Meta-Analysis
Abstract

Evolving debate suggests that C-reactive protein (CRP) might be associated with the development of venous thromboembolism (VTE); however, the evidence is conflicting. We aimed to assess the prospective association of CRP with VTE risk. C-reactive protein was measured in serum samples at baseline from 2420 men aged 42–61 years, from the Kuopio Ischemic Heart Disease study. Within-person variability in CRP levels was corrected for using repeat measurements of CRP taken 11 years after baseline. Incident VTE events (n = 119) were recorded during a median follow-up of 24.7 years. The age-adjusted regression dilution ratio for loge CRP was 0.57 [95% confidence interval (CIs): 0.51–0.64]. In age-adjusted Cox regression analysis, the hazard ratio (95% CIs) for VTE per 1 standard deviation (SD) increase in loge baseline CRP was 1.17 (0.98–1.40). Further adjustment for several established and emerging risk factors did not alter the association. In a meta-analysis of nine population-based studies (including the current study) comprising 81,625 participants and 2225 VTE cases, the fully-adjusted risk estimate for VTE was 1.14 (1.08–1.19) per SD increase in loge baseline CRP. In a pooled dose–response analysis, a linear association between CRP and VTE risk was suggested (P for nonlinearity = 0.272). The pooled risk estimate for VTE per 5 mg/l increment in CRP levels was 1.23 (1.09–1.38). C-reactive protein was only modestly associated with VTE risk in the primary analysis. Pooled evidence, however, suggests that elevated CRP is associated with greater VTE risk, consistent with a linear dose–response relationship. Electronic supplementary material The online version of this article (doi:10.1007/s10654-017-0277-4) contains supplementary material, which is available to authorized users.

Published
2017

49. Effect of Polysaccharides from Acanthopanax senticosus on Intestinal Mucosal Barrier of Escherichia coli Lipopolysaccharide Challenged Mice

Author

Han, Jie, Xu, Yunhe, Yang, Di, Yu, Ning, Bai, Zishan, and Bian, Lianquan

Subjects
Inflammation, Herbal Extract, Metabolism, Epidermal Growth Factor, Pro-inflammatory Cytokines, Intestinal Barrier, Article
Abstract

To investigate the role of polysaccharide from Acanthopanax senticosus (ASPS) in preventing lipopolysaccharide (LPS)-induced intestinal injury, 18 mice (at 5 wk of age) were assigned to three groups with 6 replicates of one mouse each. Mice were administrated by oral gavage with or without ASPS (300 mg/kg body weight) for 14 days and were injected with saline or LPS at 15 days. Intestinal samples were collected at 4 h post-challenge. The results showed that ASPS ameliorated LPS-induced deterioration of digestive ability of LPS-challenged mice, indicated by an increase in intestinal lactase activity (45%, p

Published
2015

50. AcERF1B and AcERF073 Positively Regulate Indole-3-acetic Acid Degradation by Activating AcGH3.1Transcription during Postharvest Kiwifruit Ripening

Author

Gan, Zengyu, Yuan, Xin, Shan, Nan, Wan, Chunpeng, Chen, Chuying, Zhu, Liqin, Xu, Yunhe, Kai, Wenbin, Zhai, Xiawan, and Chen, Jinyin

Abstract

Ethylene can accelerate the postharvest ripening process of kiwifruit, while indole-3-acetic acid (IAA) delays it. However, the molecular mechanism by which ethylene regulates IAA degradation is unclear. Here, we found that ethephon promotes the degradation of free IAA in kiwifruit. Furthermore, ethylene can promote the expression of AcGH3.1and enhance its promoter activity. Two ethylene response factors (ERFs), AcERF1B and AcERF073, were obtained using an AcGH3.1promoter as bait for a yeast one-hybrid screening library. Both AcERF1B and AcERF073 bind to the AcGH3.1promoter to activate it. Also, AcERF1B/073 enhanced AcGH3.1expression, decreased the free IAA content, and increased the IAA-Asp content in kiwifruit. In addition, we found that the AcERF1B and AcERF073 proteins directly interact, and this interaction enhanced their binding to the AcGH3.1promoter. In summary, our results suggest that AcERF1B and AcERF073 positively regulate IAA degradation by activating AcGH3.1transcription, which accelerated postharvest kiwifruit ripening.

Published
2021
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