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910 results on '"Zhou, Tengfei"'

2. Superconducting Diode Effect and Large Magnetochiral Anisotropy in T$_d$-MoTe$_2$ Thin Film

Author

Du, Wan-Shun, Chen, Weipeng, Zhou, Yangbo, Zhou, Tengfei, Liu, Guangjian, Zhang, Zongteng, Miao, Zichuan, Jia, Hao, Liu, Song, Zhao, Yue, Zhang, Zhensheng, Chen, Tingyong, Wang, Ning, Huang, Wen, Tan, Zhen-Bing, Chen, Jing-Jing, and Yu, Da-Peng

Subjects
Condensed Matter - Superconductivity
Abstract

In the absence of time-reversal invariance, metals without inversion symmetry may exhibit nonreciprocal charge transport -- a magnetochiral anisotropy that manifests as unequal electrical resistance for opposite current flow directions. If superconductivity also sets in, the charge transmission may become dissipationless in one direction while remaining dissipative in the opposite, thereby realizing a superconducting diode. Through both direct-current and alternating-current measurements, we study the nonreciprocal effects in thin films of the noncentrosymmetric superconductor T$_d$-MoTe\textsubscript{2} with disorders. We observe nonreciprocal superconducting critical currents with a diode efficiency close to 20\%~, and a large magnetochiral anisotropy coefficient up to $\SI{5.9e8}{\per\tesla\per\ampere}$, under weak out-of-plane magnetic field in the millitesla range. The great enhancement of rectification efficiency under out-of-plane magnetic field is likely abscribed to the vortex ratchet effect, which naturally appears in the noncentrosymmetric superconductor with disorders. Intriguingly, unlike the finding in Rashba systems, the strongest in-plane nonreciprocal effect does not occur when the field is perpendicular to the current flow direction. We develop a phenomenological theory to demonstrate that this peculiar behavior can be attributed to the asymmetric structure of spin-orbit coupling in T$_d$-MoTe\textsubscript{2}. Our study highlights how the crystallographic symmetry critically impacts the nonreciprocal transport, and would further advance the research for designing the superconducting diode with the best performance., Comment: 7 pages, 5figures

Published
2023

17. Aggregated Gradient Langevin Dynamics

Author

Zhang, Chao, Xie, Jiahao, Shen, Zebang, Zhao, Peilin, Zhou, Tengfei, and Qian, Hui

Subjects
Computer Science - Machine Learning, Statistics - Machine Learning
Abstract

In this paper, we explore a general Aggregated Gradient Langevin Dynamics framework (AGLD) for the Markov Chain Monte Carlo (MCMC) sampling. We investigate the nonasymptotic convergence of AGLD with a unified analysis for different data accessing (e.g. random access, cyclic access and random reshuffle) and snapshot updating strategies, under convex and nonconvex settings respectively. It is the first time that bounds for I/O friendly strategies such as cyclic access and random reshuffle have been established in the MCMC literature. The theoretic results also indicate that methods in AGLD possess the merits of both the low per-iteration computational complexity and the short mixture time. Empirical studies demonstrate that our framework allows to derive novel schemes to generate high-quality samples for large-scale Bayesian posterior learning tasks.

Published
2019

19. Field investigation combined with modeling uncovers the ecological heterogeneity of Aedes albopictus habitats for strategically improving systematic management during urbanization

Author

Guo, Xiang, Luo, Lei, Long, Yuxiang, Teng, Pingying, Wei, Yuehong, Xie, Tian, Li, Li, Yin, Qingqing, Li, Ziyao, Wang, Yuji, He, Jiejun, Ji, Xiatian, Zhou, Huasheng, Zhang, Xiaofan, Chen, Shigang, Zhou, Yezhen, Xu, Kaihui, Liang, Guancong, Kuang, Haocheng, Gao, Yuting, Liu, Xiaohua, Luo, Luting, Ding, Lin, Li, Yiji, Liu, Zhuanzhuan, Zhou, Tengfei, Lai, Zetian, Su, Xinghua, Guo, Yuyan, Li, Chenying, Xie, Lihua, Li, Minqing, Wu, Xinglong, Huang, Jianhao, Su, Weicong, Pan, Yicheng, Hu, Wei, Zhou, Dongrui, Li, Chunv, Gui, Juan, Ma, Jiazhi, Feng, Xiaoli, Zhu, Minyi, Zhong, Shangbin, Chen, Fan, Zeng, Huanchao, Wu, Yingxian, Wang, Chen, Li, Shukai, Wang, Qi, Wang, Xueyi, Zhou, Yekai, Ling, Jianxun, Liu, Yingjie, Wu, Shang, Li, Zhiwei, Zhong, Minghui, Wei, Wenxia, Xie, Lixian, Xu, Xianli, Huang, Hehai, Yang, Guilan, Liu, Yan, Liang, Siting, Wu, Yingxia, Zhang, Deyu, Xu, Changqing, Wang, Jie, Wang, Chunmei, Wu, Rangke, Yang, Zhicong, Chen, Xiao-Guang, and Zhou, Xiaohong

Published
2023
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20. Vertical transmission of zika virus in Aedes albopictus.

Author

Lai, Zetian, Zhou, Tengfei, Zhou, Jiayong, Liu, Shuang, Xu, Ye, Gu, Jinbao, Yan, Guiyun, and Chen, Xiao-Guang

Subjects
Biological Sciences, Medical and Health Sciences, Tropical Medicine
Abstract

BackgroundZika virus (ZIKV) is an arthropod-borne flavivirus transmitted by Aedes mosquitoes. Aedes albopictus is an important vector of ZIKV worldwide. To date, most experiments have focused on the vertical transmission of ZIKV in Ae. aegypti, while studies on Ae. albopictus are very limited. To explore vertical transmission in Ae. albopictus, a series of laboratory studies were carried out.Methodology/principal findingsIn this study, Ae. albopictus were blood-fed with ZIKV-infectious blood, and the ovaries and offspring viral infection rates were analyzed by reverse transcription PCR (RT-PCR), real-time reverse transcription PCR (RT-qPCR) and immunohistochemistry (IHC). ZIKV was detected in the ovaries and oviposited eggs in two gonotrophic cycles. The minimum filial egg infection rates in two gonotrophic cycles were 2.06% and 0.69%, and the effective population transmission rate was 1.87%. The hatching, pupation, and emergence rates of infected offspring were not significantly different from those of uninfected offspring, indicating that ZIKV did not prevent the offspring from completing the growth and development process. ZIKV was detected in three of thirteen C57BL/6 suckling mice bitten by ZIKV-positive F1 females, and the viremia persisted for at least seven days.Conclusions/significanceZIKV can be vertically transmitted in Ae. albopictus via transovarial transmission. The vertical transmission rates in F1 eggs and adults were 2.06% and 1.87%, respectively. Even though the vertical transmission rates were low, the female mosquitoes infected via the congenital route horizontally transmitted ZIKV to suckling mice through bloodsucking. This is the first experimental evidence of offspring with vertically transmitted ZIKV initiating new horizontal transmission. The present study deepens the understanding of the vertical transmission of flaviviruses in Aedes mosquitoes and sheds light on the prevention and control of mosquito-borne diseases.

Published
2020

22. Community recommendations for geochemical data, services and analytical capabilities in the 21st century

Author

Klöcking, Marthe, Wyborn, Lesley, Lehnert, Kerstin A., Ware, Bryant, Prent, Alexander M., Profeta, Lucia, Kohlmann, Fabian, Noble, Wayne, Bruno, Ian, Lambart, Sarah, Ananuer, Halimulati, Barber, Nicholas D., Becker, Harry, Brodbeck, Maurice, Deng, Hang, Deng, Kai, Elger, Kirsten, de Souza Franco, Gabriel, Gao, Yajie, Ghasera, Khalid Mohammed, Hezel, Dominik C., Huang, Jingyi, Kerswell, Buchanan, Koch, Hilde, Lanati, Anthony W., ter Maat, Geertje, Martínez-Villegas, Nadia, Nana Yobo, Lucien, Redaa, Ahmad, Schäfer, Wiebke, Swing, Megan R., Taylor, Richard J.M., Traun, Marie Katrine, Whelan, Jo, and Zhou, Tengfei

Published
2023
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26. Towards More Efficient Stochastic Decentralized Learning: Faster Convergence and Sparse Communication

Author

Shen, Zebang, Mokhtari, Aryan, Zhou, Tengfei, Zhao, Peilin, and Qian, Hui

Subjects
Statistics - Machine Learning, Computer Science - Learning
Abstract

Recently, the decentralized optimization problem is attracting growing attention. Most existing methods are deterministic with high per-iteration cost and have a convergence rate quadratically depending on the problem condition number. Besides, the dense communication is necessary to ensure the convergence even if the dataset is sparse. In this paper, we generalize the decentralized optimization problem to a monotone operator root finding problem, and propose a stochastic algorithm named DSBA that (i) converges geometrically with a rate linearly depending on the problem condition number, and (ii) can be implemented using sparse communication only. Additionally, DSBA handles learning problems like AUC-maximization which cannot be tackled efficiently in the decentralized setting. Experiments on convex minimization and AUC-maximization validate the efficiency of our method., Comment: Accepted to ICML 2018

Published
2018

28. Fast emerging insecticide resistance in Aedes albopictus in Guangzhou, China: Alarm to the dengue epidemic.

Author

Su, Xinghua, Guo, Yijia, Deng, Jielin, Xu, Jiabao, Zhou, Guofa, Zhou, Tengfei, Li, Yiji, Zhong, Daibin, Kong, Ling, Wang, Xiaoming, Liu, Min, Wu, Kun, Yan, Guiyun, and Chen, Xiao-Guang

Subjects
Tropical Medicine, Biological Sciences, Medical and Health Sciences
Abstract

Dengue is one of the most serious mosquito-borne infectious diseases in the world. Aedes albopictus is the most invasive mosquito and one of the primary vectors of dengue. Vector control using insecticides is the only viable strategy to prevent dengue virus transmission. In Guangzhou, after the 2014 pandemic, massive insecticides have been implemented. Massive insecticide use may lead to the development of resistance, but few reports are available on the status of insecticide resistance in Guangzhou after 2014. In this study, Ae. albopictus were collected from four districts with varied dengue virus transmission intensity in Guangzhou from 2015 to 2017. Adult Ae. albopictus insecticide susceptibility to deltamethrin (0.03%), permethrin(0.25%), DDT(4%), malathion (0.8%) and bendiocarb (0.1%) was determined by the standard WHO tube test, and larval resistance bioassays were conducted using temephos, Bacillus thuringiensis israelensis (Bti), pyriproxyfen (PPF) and hexaflumuron. Mutations at the voltage-gated sodium channel (VGSC) gene and acetylcholinesterase (AChE) gene were analyzed. The effect of cytochrome P450s on the resistance of Ae. albopictus to deltamethrin was tested using the synergistic agent piperonyl butoxide (PBO). The results showed that Ae. albopictus populations have rapidly developed very high resistances to multiple commonly used insecticides at all study areas except malathion, Bti and hexaflumuron. We found 1534 codon mutations in the VGSC gene that were significantly correlated with the resistance to pyrethroids and DDT, and 11 synonymous mutations were also found in the gene. The resistance to deltamethrin can be significantly reduced by PBO but may generated cross-resistance to PPF. Fast emerging resistance in Ae. albopictus may affect mosquito management and threaten the prevention and control of dengue, similar to the resistance in Anopheles mosquitoes has prevented the elimination of malaria and call for timely and guided insecticide management.

Published
2019

33. Bimetallic Ion Intercalation Optimized the Performance of Hydrated Vanadate Cathodes for Aqueous Zinc Ion Batteries.

Author

Xiao, An, Zhou, Tengfei, Xiang, Dan, Zou, Sijia, Zhang, Tian, Zhang, Longhan, Zhang, Qixiong, Hou, Yafei, Zhu, Yuejin, Li, Weiping, Zhang, Chaofeng, and Cuan, Jing

Abstract

Aqueous zinc ion batteries are gaining prominent attention due to their potentially high safety, low cost, and high volumetric capacity. However, disparities still exist in specific capacity and kinetic performances within the electrode materials of zinc ion batteries. Herein, the electrochemical and kinetic properties of layered vanadium oxide (VOH) nanorods adopting Sr2+ and La3+ as pillars were investigated systematically. It was shown that (1La,1Sr)-VOH possessed a specific capacity around 345.8 mAh g–1 at a current density of 1 A g–1, which was remarkably higher than that of VOH and 1Sr-VOH (208.34 mAh g–1). Characterizations demonstrated that benefiting from the role of Sr2+ and La3+ as pillars, (1La,1Sr)-VOH possessed enlarged layer spacing and enhanced zinc ion storage kinetics during electrochemical reactions. The tested zinc ion diffusion coefficient was 1.16 × 10–11 cm2 s–1, which was much higher than that of VOH (7.31 × 10–12 cm2 s–1), demonstrating a smooth charge transfer process in the as-synthesized (1La,1Sr)-VOH. [ABSTRACT FROM AUTHOR]

Published
2025
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39. Accelerated Variance Reduced Block Coordinate Descent

Author

Shen, Zebang, Qian, Hui, Zhang, Chao, and Zhou, Tengfei

Subjects
Statistics - Machine Learning, Computer Science - Learning
Abstract

Algorithms with fast convergence, small number of data access, and low per-iteration complexity are particularly favorable in the big data era, due to the demand for obtaining \emph{highly accurate solutions} to problems with \emph{a large number of samples} in \emph{ultra-high} dimensional space. Existing algorithms lack at least one of these qualities, and thus are inefficient in handling such big data challenge. In this paper, we propose a method enjoying all these merits with an accelerated convergence rate $O(\frac{1}{k^2})$. Empirical studies on large scale datasets with more than one million features are conducted to show the effectiveness of our methods in practice.

Published
2016

40. Riemannian Tensor Completion with Side Information

Author

Zhou, Tengfei, Qian, Hui, Shen, Zebang, and Xu, Congfu

Subjects
Statistics - Machine Learning, Computer Science - Learning, Computer Science - Numerical Analysis
Abstract

By restricting the iterate on a nonlinear manifold, the recently proposed Riemannian optimization methods prove to be both efficient and effective in low rank tensor completion problems. However, existing methods fail to exploit the easily accessible side information, due to their format mismatch. Consequently, there is still room for improvement in such methods. To fill the gap, in this paper, a novel Riemannian model is proposed to organically integrate the original model and the side information by overcoming their inconsistency. For this particular model, an efficient Riemannian conjugate gradient descent solver is devised based on a new metric that captures the curvature of the objective.Numerical experiments suggest that our solver is more accurate than the state-of-the-art without compromising the efficiency.

Published
2016

41. Accelerated Stochastic ADMM with Variance Reduction

Author

Zhang, Chao, Shen, Zebang, Qian, Hui, Zhou, Tengfei, Zhou, Jianya, and Zhou, Jianying

Subjects
Mathematics - Numerical Analysis, Mathematics - Optimization and Control
Abstract

Alternating Direction Method of Multipliers (ADMM) is a popular method for solving large-scale Machine Learning problems. Stochastic ADMM was proposed to reduce the per iteration computational complexity, which is more suitable for big data problems. Recently, variance reduction techniques have been integrated with stochastic ADMM in order to get a faster convergence rate, such as SAG-ADMM and SVRG-ADMM. However, their convergence rate is still suboptimal w.r.t the smoothness constant. In this paper, we propose an accelerated stochastic ADMM algorithm with variance reduction, which enjoys a faster convergence than all the existing stochastic ADMM algorithms. We theoretically analyse its convergence rate and show its dependence on the smoothness constant is optimal. We also empirically validate its effectiveness and show its priority over other stochastic ADMM algorithms.

Published
2016

44. Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China.

Author

Liu, Zhuanzhuan, Zhou, Tengfei, Lai, Zetian, Zhang, Zhenhong, Jia, Zhirong, Zhou, Guofa, Williams, Tricia, Xu, Jiabao, Gu, Jinbao, Zhou, Xiaohong, Lin, Lifeng, Yan, Guiyun, and Chen, Xiao-Guang

Subjects
Cell Line, Animals, Aedes, Culex, RNA, Viral, Viral Load, Insect Vectors, Virus Replication, China, Female, Zika Virus, Zika Virus Infection, Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, Zika virus, mosquitoes, vector competence, vector-borne infections, viruses, RNA, Viral, Microbiology, Medical Microbiology, Public Health and Health Services, Clinical Sciences
Abstract

In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies.

Published
2017

48. Biowastes for Metal–Sulfur Batteries

Author

Zhang, Chaofeng, primary, Ma, Quanwei, additional, Zhang, Longhai, additional, Wang, Rui, additional, Li, Hao, additional, Zhou, Tengfei, additional, and Yuan, Changzhou, additional

Published
2022
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49. Off-Policy Recommendation System Without Exploration

Author

Wang, Chengwei, Zhou, Tengfei, Chen, Chen, Hu, Tianlei, Chen, Gang, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Lauw, Hady W., editor, Wong, Raymond Chi-Wing, editor, Ntoulas, Alexandros, editor, Lim, Ee-Peng, editor, Ng, See-Kiong, editor, and Pan, Sinno Jialin, editor

Published
2020
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