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1,348 results on '"Lv Zheng"'

1. Metformin alleviates cryoinjuries in porcine oocytes by reducing membrane fluidity through the suppression of mitochondrial activity

Author

Dan Zhou, Hongyu Liu, Lv Zheng, Aiju Liu, Qingrui Zhuan, Yuwen Luo, Guizhen Zhou, Lin Meng, Yunpeng Hou, Guoquan Wu, Jun Li, and Xiangwei Fu

Subjects
Biology (General), QH301-705.5
Abstract

Abstract Plasma membrane damage in vitrified oocytes is closely linked to mitochondrial dysfunction. However, the mechanism underlying mitochondria-regulated membrane stability is not elucidated. A growing body of evidence indicates that mitochondrial activity plays a pivotal role in cell adaptation. Since mitochondria work at a higher temperature than the constant external temperature of the cell, we hypothesize that suppressing mitochondrial activity would protect oocytes from extreme stimuli during vitrification. Here we show that metformin suppresses mitochondrial activity by reducing mitochondrial temperature. In addition, metformin affects the developmental potential of oocytes and improves the survival rate after vitrification. Transmission electron microscopy results show that mitochondrial abnormalities are markedly reduced in vitrified oocytes pretreated with metformin. Moreover, we find that metformin transiently inhibits mitochondrial activity. Interestingly, metformin pretreatment decreases cell membrane fluidity after vitrification. Furthermore, transcriptome results demonstrate that metformin pretreatment modulates the expression levels of genes involved in fatty acid elongation process, which is further verified by the increased long-chain saturated fatty acid contents in metformin-pretreated vitrified oocytes by lipidomic profile analysis. In summary, our study indicates that metformin alleviates cryoinjuries by reducing membrane fluidity via mitochondrial activity regulation.

Published
2024
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2. Numerical simulation and experimental research on cracking mechanism of twin-roll strip casting

Author

Lv Zheng, Yang Zhou-Yi, Zhang Jian-Yu, Li Xue-Tong, Ji Peng, Zhou Qian, Zhang Xi-Liang, and Shi Yin-Dong

Subjects
twin-roll strip casting, mathematical model, kiss curve, oblique crack, Technology, Chemical technology, TP1-1185, Chemicals: Manufacture, use, etc., TP200-248
Abstract

Based on the three-dimensional field of molten pool and twin-roll strip casting experiments, this work verified the cracking mechanism of the strip by establishing mathematical model and rolling experiments. The results showed that due to the instability of the thermophysical field of the molten pool and the inconsistency of kiss curve height, the newly solidified strip will undergo incompatible deformation through the rolling. The stress concentration will appear around the large reduction area and then form slip bands. When plastic strain exceeds the limit of the metal, the oblique cracks will appear in the slip bands periodically or completely penetrate the strip. In addition, tensile cracks could also be produced by incompatible deformation. Therefore, keeping the uniformity and stability of the thermal physical field in molten pool is the key factor to restrain cracks.

Published
2022
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3. Microstructure and mechanical properties of NbC–Ni cermets prepared by microwave sintering

Author

Tang Siwen, Zhang Hao, Yang Zhifu, Liu Qian, Lv Zheng, Ouyang Cong, and Qiu Xinyi

Subjects
nbc–ni cermets, microwave sintering, microstructure, mechanical property, Technology, Chemical technology, TP1-1185, Chemicals: Manufacture, use, etc., TP200-248
Abstract

This study shows the application of microwave sintering (MS) on preparing NbC–10Ni and NbC–12Ni cermets, as well as the effect of its microstructure, phase formation, and mechanical properties. Results indicated that NbC–Ni cermets with a fine and uniform structure can be obtained by MS in a relatively short time. And the sintering temperature greatly influenced the microstructure and mechanical properties of NbC–Ni cermets, whereas the effect of dwell time is relatively small. With the increase of the sintering temperature, the microstructure of NbC–Ni cermets experienced sintering densification and grain growth. The strength and toughness increased first and then decreased, and the hardness increased with the increase of sintering temperature. According to the comprehensive mechanical properties, the optimized sintering process is 1,390°C and the dwell time is 15 min. At this time, no new phase formed, but the diffraction peak of the Ni phase shifted. Through analysis, it is found that the improvement mechanisms for comprehensive mechanical properties of NbC–Ni cermets mainly include grain refinement, crack deflection and bridging, and energy absorption of the ductile phase of Ni.

Published
2022
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4. Numerical and experimental research on solidification of T2 copper alloy during the twin-roll casting

Author

Lv Zheng, Sun Zhen-Jun, Hou Zhi-Hui, Yang Zhou-Yi, Zhang Xi-Liang, and Shi Yin-Dong

Subjects
t2 copper, twin-roll strip casting, dendritic growth, kiss point, Technology, Chemical technology, TP1-1185, Chemicals: Manufacture, use, etc., TP200-248
Abstract

Based on CAFE theory and KGT model, the twin-roll strip casting mathematical model was established to solve the dendrite growth and solidification of T2 copper alloy in the molten pool. The influence mechanism of casting temperature, heat transfer, and other technological conditions on the microstructure of strip was analyzed. The results showed that the liquid metal formed 35 µm chilling layer after touching the rollers, and the layer was consisted of a high number of small and equiaxed crystals. Then some grains would appear close to the newly chilling layer, and grow toward the core of molten pool competitively. The dominant grains mainly grew along the 〈001〉 orientation into columnar crystals, and the rest grains that grew out of alignment were eliminated gradually. The number of grains declined, and the radius of columnar grains became coarsening. The Kiss point is a key factor for solidification structure, and the lower location of the Kiss point could limit the growth spaces of columnar crystals, which refined the grains.

Published
2022
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5. EMHI: A Multimodal Egocentric Human Motion Dataset with HMD and Body-Worn IMUs

Author

Fan, Zhen, Dai, Peng, Su, Zhuo, Gao, Xu, Lv, Zheng, Zhang, Jiarui, Du, Tianyuan, Wang, Guidong, and Zhang, Yang

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Egocentric human pose estimation (HPE) using wearable sensors is essential for VR/AR applications. Most methods rely solely on either egocentric-view images or sparse Inertial Measurement Unit (IMU) signals, leading to inaccuracies due to self-occlusion in images or the sparseness and drift of inertial sensors. Most importantly, the lack of real-world datasets containing both modalities is a major obstacle to progress in this field. To overcome the barrier, we propose EMHI, a multimodal \textbf{E}gocentric human \textbf{M}otion dataset with \textbf{H}ead-Mounted Display (HMD) and body-worn \textbf{I}MUs, with all data collected under the real VR product suite. Specifically, EMHI provides synchronized stereo images from downward-sloping cameras on the headset and IMU data from body-worn sensors, along with pose annotations in SMPL format. This dataset consists of 885 sequences captured by 58 subjects performing 39 actions, totaling about 28.5 hours of recording. We evaluate the annotations by comparing them with optical marker-based SMPL fitting results. To substantiate the reliability of our dataset, we introduce MEPoser, a new baseline method for multimodal egocentric HPE, which employs a multimodal fusion encoder, temporal feature encoder, and MLP-based regression heads. The experiments on EMHI show that MEPoser outperforms existing single-modal methods and demonstrates the value of our dataset in solving the problem of egocentric HPE. We believe the release of EMHI and the method could advance the research of egocentric HPE and expedite the practical implementation of this technology in VR/AR products.

Published
2024

6. HeadGAP: Few-shot 3D Head Avatar via Generalizable Gaussian Priors

Author

Zheng, Xiaozheng, Wen, Chao, Li, Zhaohu, Zhang, Weiyi, Su, Zhuo, Chang, Xu, Zhao, Yang, Lv, Zheng, Zhang, Xiaoyuan, Zhang, Yongjie, Wang, Guidong, and Xu, Lan

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

In this paper, we present a novel 3D head avatar creation approach capable of generalizing from few-shot in-the-wild data with high-fidelity and animatable robustness. Given the underconstrained nature of this problem, incorporating prior knowledge is essential. Therefore, we propose a framework comprising prior learning and avatar creation phases. The prior learning phase leverages 3D head priors derived from a large-scale multi-view dynamic dataset, and the avatar creation phase applies these priors for few-shot personalization. Our approach effectively captures these priors by utilizing a Gaussian Splatting-based auto-decoder network with part-based dynamic modeling. Our method employs identity-shared encoding with personalized latent codes for individual identities to learn the attributes of Gaussian primitives. During the avatar creation phase, we achieve fast head avatar personalization by leveraging inversion and fine-tuning strategies. Extensive experiments demonstrate that our model effectively exploits head priors and successfully generalizes them to few-shot personalization, achieving photo-realistic rendering quality, multi-view consistency, and stable animation., Comment: Project page: https://headgap.github.io/

Published
2024

7. The Genesis of the Askartor Be-Mo Deposit in the North Xinjiang, Northwest China: Evidence From Geology, Geochemistry, U-Pb, and Re-Os Geochronology

Author

Tang Yong, Zhang Hui, and Lv Zheng-Hang

Subjects
Askartor Be deposit, U-Pb age, tetrad effect, melt-fluid interaction, NW China, Science
Abstract

The Askartor Be-Mo deposit is located in the southeastern area of the Chinese Altay orogenic belt in Xinjiang, NW China. Zircon U-Pb data show that there are two periods of magmatic activities in the Askartor Be-Mo ore district, namely, the Devonian granodiorite (386.8 ± 2.6 Ma) and biotite granite (385.4 ± 4.4 Ma), and the Triassic two-mica granite (247.5 ± 2.2 Ma) and muscovite granite (231.4 ± 2.0 Ma). The zircon U-Pb age of pegmatoid orebody is 220.6 ± 1.6 Ma which coincides with the molybdenite Re-Os isochron age of 228.7 ± 7.1 Ma. The two-mica and muscovite granites belong to the high-K Calc-alkaline series with peraluminous features, and are characterized by high SiO2 (71.92–75.41 wt%), and Al2O3 (13.43–15.98 wt%), and low TiO2 (0.01–0.25 wt%), Fe2O3 (0.11–1.14 wt%) and CaO (0.07–0.76 wt%). The highly fractionated element ratios of Y/Ho, Zr/Hf and Nb/Ta, and the rare earth element tetrad effect occur in the muscovite granite, indicating the fluid exsolution occurs at the late stage of magma evolution, and the muscovite granite experienced the strong self-metasomatism. Rayleigh fractional calculations show that the Askartor Be-Mo deposit is the product of multistage fractional crystallization of initial Be-enriched magma.

Published
2021
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10. Design of Satellite Constellation Based on Bamboo Resources Carbon Sink Monitoring

Author

Huang, Yufei, Lv, Zheng, Mao, Yilan, Yang, Yuanyuan, Liu, Shuai, Yang, Yan, Zuo, Bo, Wang, Qian, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Tan, Kay Chen, Series Editor, Wang, Yue, editor, Zou, Jiaqi, editor, Xu, Lexi, editor, Ling, Zhilei, editor, and Cheng, Xinzhou, editor

Published
2024
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11. Analysis of Factors Affecting Image Quality of Optical Maneuvring Imaging Satellite

Author

Shao, Jun, Wang, Xiaoyan, Lv, Zheng, Li, Xiaojin, Zhong, Huimin, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Tan, Kay Chen, Series Editor, Wang, Yue, editor, Zou, Jiaqi, editor, Xu, Lexi, editor, Ling, Zhilei, editor, and Cheng, Xinzhou, editor

Published
2024
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12. Rice Extraction in Sanjiang Plain Based on Remote Sensing Data and Optimal Feature Spaces

Author

Wang, Xiaoyan, Shao, Guowen, Shao, Jun, Lv, Zheng, Li, Junjie, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Tan, Kay Chen, Series Editor, Wang, Yue, editor, Zou, Jiaqi, editor, Xu, Lexi, editor, Ling, Zhilei, editor, and Cheng, Xinzhou, editor

Published
2024
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13. Channel Imbalance Calibration for Digital Beamforming SAR System in Elevation

Author

Zhou, Yashi, Han, Xiaolei, An, Liang, Ma, Jian, Lv, Zheng, Hou, Wentao, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Tan, Kay Chen, Series Editor, Wang, Wei, editor, Liu, Xin, editor, Na, Zhenyu, editor, and Zhang, Baoju, editor

Published
2024
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14. ESTNet: Efficient Spatio-Temporal Network for Industrial Smoke Detection

Author

Du, Shuo, Lv, Zheng, Wang, Linqing, Zhao, Jun, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Luo, Biao, editor, Cheng, Long, editor, Wu, Zheng-Guang, editor, Li, Hongyi, editor, and Li, Chaojie, editor

Published
2024
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22. Evaluating the impact of quarantine measures on COVID-19 spread

Author

Zhang, Renquan, Wang, Yu, Lv, Zheng, and Pei, Sen

Subjects
Quantitative Biology - Populations and Evolution
Abstract

During the early stage of the COVID-19 pandemic, many countries implemented non-pharmaceutical interventions (NPIs) to control the transmission of SARS-CoV-2, the causative pathogen of COVID-19. Among those NPIs, quarantine measures were widely adopted and enforced through stay-at-home and shelter-in-place orders. Understanding the effectiveness of quarantine measures can inform decision-making and control planning during the ongoing COVID-19 pandemic and for future disease outbreaks. In this study, we use mathematical models to evaluate the impact of quarantine measures on COVID-19 spread in four cities that experienced large-scale outbreaks in the spring of 2020: Wuhan, New York, Milan, and London. We develop a susceptible-exposed-infected-removed (SEIR)-type model with a component of quarantine and couple this disease transmission model with a data assimilation method. By calibrating the model to case data, we estimate key epidemiological parameters before lockdown in each city. We further examine the impact of quarantine rates on COVID-19 spread after lockdown using model simulations. Results indicate that quarantine of susceptible and exposed individuals and undetected infections is necessary to contain the outbreak; however, the quarantine rates for these populations can be reduced through faster isolation of confirmed cases. We generate counterfactual simulations to estimate effectiveness of quarantine measures. Without quarantine measures, the cumulative confirmed cases could be 73, 22, 43 and 93 times higher than reported numbers within 40 days after lockdown in Wuhan, New York, Milan, and London. Our findings underscore the essential role of quarantine during the early phase of the pandemic., Comment: 13 pages, 5 figures

Published
2022

38. Development of LDV-Based Length Measuring Equipment for Tension Stranding Construction Conductor

Author

Lv, Zheng, Huang, Zhiming, Xiao, Qi, Li, Zixin, Guan, Junfeng, Tang, Bo, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Tan, Kay Chen, Series Editor, Dong, Xuzhu, editor, Yang, Qingxin, editor, and Ma, Weiming, editor

Published
2023
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