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773 results on '"Yu, Guanghui"'

208. Rusty sink of rhizodeposits and associated keystone microbiomes

Author

Jeewani, Peduruhewa H., primary, Gunina, Anna, additional, Tao, Liang, additional, Zhu, Zhenke, additional, Kuzyakov, Yakov, additional, Van Zwieten, Lukas, additional, Guggenberger, Georg, additional, Shen, Congcong, additional, Yu, Guanghui, additional, Singh, Bhupinder Pal, additional, Pan, Shaotong, additional, Luo, Yu, additional, and Xu, Jianming, additional

Published
2020
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224. Non-diffusive cross field transport in scrape-off-layer in Tokamak

Author

Yu, Guanghui

Abstract

In recent years, coherent structures in edge plasmas are believed to be one of the major factors in cross-field transport. The present dissertation is dedicated to using theoretical and numerical methods to study the dynamics of individual coherent structure, or so-called blob, moving from bulk plasma to the chamber wall. Blob is a filament structure extended along magnetic filed lines. We focus on two different types of blob. One is ending up at target plates, the other is not, i.e. the SOL and HB blobs. Two dimensional blob models are derived. Characteristic spatial scale , time scale , and velocity for blob are obtained and calculated for different tokamaks. They are in agreement with experimental measurements. Scaling analysis shows blob dynamics sensitive to spatial scale length. Stability analysis shows that blobs with spatial scales less than may move as coherent structures to large distances. In the SOL model simulation we have found the most structurally stable blob has scale length around . Blobs smaller than evolve into mushroom-like structures. Blobs larger than are subject to the fingering instability. Blobs with spatial scales close to can coherently move to long distances. Simulation results show that high density background effectively narrows down blob size and the inertia term in vorticity equation drives blob to mushroom shape and builds up vortex dipole within the structure. We also compare results with and without the Boussinesq approximation. In the HB model simulation it is shown that blobs have wider stable range. Their steep nose and long relaxation tail can explain experimentally detected asymmetric profile. HB blob moves with a constant velocity. In the biasing potential model a critical magnitude of the potential barrier is derived. A strong deformation of the blob as coherent structure will be observed while blob pass through a barrier higher than the critical value. Simulation results confirm the theoretical prediction. In the rotational blob model simulation results show the suppression of radial velocity and the generation of poloidal velocity. Fingering and mushroom effects are inhibited, but blobs evolve into rotational instability at later stage

Published
2006

228. 近20年来中国能源消费碳排放时空格局动态

Author

SU Qing, LI Chao-kui, Zhang Yong, Gao Changchun, Liu Xianzhao, Yu Guanghui, and Tian Yanlin

Subjects
Geography, 010504 meteorology & atmospheric sciences, Ecology, 05 social sciences, Geography, Planning and Development, 0507 social and economic geography, Earth and Planetary Sciences (miscellaneous), 050703 geography, 01 natural sciences, 0105 earth and related environmental sciences, Nature and Landscape Conservation
Published
2016

229. Improving manure nutrient management towards sustainable agricultural intensification in China

Author

David R. Chadwick, Shen Qi-rong, Jia Wei, Yu Guanghui, Chen Qing, and Tong Yan'an

Subjects
Manure management, education.field_of_study, Ecology, business.industry, Nutrient management, Agroforestry, Population, Manure, Biogas, Agronomy, Sustainability, Food processing, Animal Science and Zoology, Livestock, business, education, Agronomy and Crop Science
Abstract

Traditionally farmers in China have relied on organic manures to build the organic matter content in soil and to fertilise crops for both human and livestock consumption. However, with requirements to increase food production, the use of relatively cheap inorganic fertilisers has increased, and manure nutrients are not always used to their potential. In addition, farms of all sizes and even biogas plants, often lack the basic infrastructure to manage manures; poor containment facilities often result in untreated manures being discharged directly into watercourses, whilst transportation of manures to the field and land spreading is often not mechanised and relies on availability of suitable labour. There is already clear evidence of overuse of nutrients in some parts of China and this is causing undesirable impacts on the environment. With the increasing demand for livestock products from a burgeoning population and changes in dietary preferences towards animal protein, greater quantities of manure nutrients will be generated in the next twenty years, especially in peri-urban concentrated animal feeding operations and intensive farms. It is essential that China addresses the infrastructural, research and communication challenges to ensure that manures are integrated into nutrient planning at the field, farm and regional level to safeguard the environment, reduce the requirement for inorganic fertiliser production and use, and improve farmer incomes. This paper reviews the current manure management practices, both nationally and, where appropriate, at a regional scale, and assesses what barriers currently prevent efficient manure nutrient utilisation in China. We then address the future challenges for manure nutrient management in China, before summarising key gaps in knowledge and communication with implications for research and policy.

Published
2015

230. Metal‐Contact‐Induced Transition of Electrical Transport in Monolayer MoS2: From Thermally Activated to Variable‐Range Hopping.

Author

Peng, Songang, Jin, Zhi, Yao, Yao, Li, Ling, Zhang, Dayong, Shi, Jingyuan, Huang, Xinnan, Niu, Jiebin, Zhang, Yanhui, and Yu, Guanghui

Subjects
INFORMATION storage & retrieval systems, APOLOGIZING
Abstract

The article titled "Metal-Contact-Induced Transition of Electrical Transport in Monolayer MoS2: From Thermally Activated to Variable-Range Hopping" was published in Advanced Electronic Materials in 2019. The article acknowledges additional funders that were not initially listed in the manuscript. The authors apologize for any inconvenience caused, but assure that these additions do not impact the conclusions of the paper. The authors of the article are Songang Peng, Zhi Jin, Yao Yao, Ling Li, Dayong Zhang, Jingyuan Shi, Xinnan Huang, Jiebin Niu, Yanhui Zhang, and Guanghui Yu. [Extracted from the article]

Published
2024
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234. Single‐Crystal Graphene Wafers: Epitaxial Growth of 6 in. Single‐Crystalline Graphene on a Cu/Ni (111) Film at 750 °C via Chemical Vapor Deposition (Small 22/2019)

Author

Zhang, Xuefu, primary, Wu, Tianru, additional, Jiang, Qi, additional, Wang, Huishan, additional, Zhu, Hailong, additional, Chen, Zhiying, additional, Jiang, Ren, additional, Niu, Tianchao, additional, Li, Zhuojun, additional, Zhang, Youwei, additional, Qiu, Zhijun, additional, Yu, Guanghui, additional, Li, Ang, additional, Qiao, Shan, additional, Wang, Haomin, additional, Yu, Qingkai, additional, and Xie, Xiaoming, additional

Published
2019
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236. Epitaxial Growth of 6 in. Single‐Crystalline Graphene on a Cu/Ni (111) Film at 750 °C via Chemical Vapor Deposition

Author

Zhang, Xuefu, primary, Wu, Tianru, additional, Jiang, Qi, additional, Wang, Huishan, additional, Zhu, Hailong, additional, Chen, Zhiying, additional, Jiang, Ren, additional, Niu, Tianchao, additional, Li, Zhuojun, additional, Zhang, Youwei, additional, Qiu, Zhijun, additional, Yu, Guanghui, additional, Li, Ang, additional, Qiao, Shan, additional, Wang, Haomin, additional, Yu, Qingkai, additional, and Xie, Xiaoming, additional

Published
2019
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245. Sampler Design for Bayesian Personalized Ranking by Leveraging View Data.

Author

Ding, Jingtao, Yu, Guanghui, He, Xiangnan, Feng, Fuli, Li, Yong, and Jin, Depeng

Subjects
*RECOMMENDER systems, *LEARNING strategies, *STREAMING media
Abstract

Bayesian Personalized Ranking (BPR) is a representative pairwise learning method for optimizing recommendation models. It is widely known that the performance of BPR depends largely on the quality of negative sampler. In this paper, we make two contributions with respect to BPR. First, we find that sampling negative items from the whole space is unnecessary and may even degrade the performance. Second, focusing on the purchase feedback of E-commerce, we propose a negative sampler for BPR by leveraging the additional view data. In our proposed sampler, users’ viewed interactions are considered as an intermediate feedback between the purchased and unobserved interactions. We jointly learn the pairwise rankings of user preference among these three types of interactions and design a user-oriented weighting strategy during learning process, which is more effective and flexible. Compared to the vanilla BPR that applies a uniform sampler on all candidates, our view-enhanced sampler enhances BPR with a relative improvement over 36.64 and 16.40 percent on Beibei and Tmall datasets, respectively. Empirical studies demonstrate the importance of considering users’ additional feedback when modeling their preference on different items, which can effectively improve the quality of sampled negative items towards learning a better personalized ranking function. Our implementation is available at https://github.com/dingjingtao/NegativeSamplerBPR. [ABSTRACT FROM AUTHOR]

Published
2021
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246. Predicting the Evolution of Hot Topics: A Solution Based on the Online Opinion Dynamics Model in Social Network.

Author

Jiang, Lei, Liu, Jujun, Zhou, Dong, Zhou, Qian, Yang, Xiansheng, and Yu, Guanghui

Subjects
SOCIAL networks, FORECASTING, SOCIAL dynamics, COMPUTER simulation, PREDICTION models
Abstract

Predicting and utilizing the evolution trend of hot topics is critical for contingency management and decision-making purposes of government bodies and enterprises. This paper proposes a model named online opinion dynamics (OODs) where any node in a social network has its unique confidence threshold and influence radius. The nodes in the OOD are mainly affected by their neighbors and are also randomly influenced by unfamiliar nodes. In the traditional opinion model, however, each node is affected by all other nodes, including its friends. Furthermore, many traditional opinion evolution approaches are reviewed to see if all nodes (participants) can eventually reach a consensus. On the contrary, OOD is more focused on such details as concluding the overall trend of events and evaluating the support level of each participant through numerical simulation. Experiments show that OOD is superior to the improvement of the original Hegselmann–Krause (HK) model, HK-13 and HK-17, with respect to qualitative predictions of the evolution trend of an event. The quantitative predictions of the HK model cannot be used to make decisions, whereas the results of the OOD model are proved to be acceptable. [ABSTRACT FROM AUTHOR]

Published
2020
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247. Investigation on aeration efficiency and energy efficiency optimization in recirculating aquaculture coupling CFD with Euler-Euler and Species Transport Model

Author

Yu, Guanghui, Zhang, Shanhong, Chen, Xiaomeng, Li, Daoliang, and Wang, Yang

Abstract

Aeration plays a crucial role in maintaining the overall health and sustainability of the recirculating aquaculture system. Conventional aeration operates continuous and consumes 35.06% of equipment energy consumption. How to optimize aeration while ensuring normal fish growth remains a great challenge. To address these challenges, this research paper established a coupled model of computational fluid dynamics and species transport model (CFD-STM). Aeration tests were carried out in a 33.3 m3culture tank using a 0.31m diameter aerator to find out the impacts of operating variables (aeration flow rate, bubble diameter, inlet velocity, and aerator position) on oxygen transfer using a microporous aeration system. A CFD-STM model was coupled to obtain the optimum values of aeration parameters. Results revealed that the Standard Aeration Efficiency (SAE) reductions by 32.1% for 50% larger aeration flow rate and 86.4% for 50% larger bubble diameter, as well as SAE achieved 5.67kg/kWh with an aerator position scale factor equal to 0.48. In addition, the energy consumption of the Roots blower was compared for a single aeration and dissolved oxygen saturation. Results indicated that smaller bubbles microbubbles can effectively improve oxygen transfer coefficient. The energy consumption was reduced by 15.7% for 50% larger aeration flow rate and 38.6% for 50% lower bubble diameter. Based on the results, this study demonstrated that CFD is a useful tool to optimize the aeration system design and operation in order to enhance aeration efficiency. It provides a theoretical foundation the future optimization of energy conservation through intermittent aeration practices.

Published
2024
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248. Detecting the Repair of Sulfur Vacancies in CVD-Grown MoS2 Domains via Hydrogen Etching.

Author

Hu, Shike, Li, Jing, Wang, Shuang, Liang, Yijian, Kang, He, Zhang, Yanhui, Chen, Zhiying, Sui, Yanping, Yu, Guanghui, Peng, Songang, Jin, Zhi, and Liu, Xinyu

Subjects
ANNEALING of metals, CHEMICAL milling, SULFUR, CHEMICAL vapor deposition, ETCHING, HYDROGEN, OPTOELECTRONIC devices
Abstract

Inherent sulfur vacancies in molybdenum disulfide (MoS2) films grown via chemical vapor deposition have restricted the practical application of MoS2 in optoelectronic devices. The repair of sulfur vacancies is important for improving the quality of MoS2 and enhancing the performance of devices based on MoS2 films. Here we report a route that uses hydrogen (H2) etching to detect the repair effect of sulfur vacancies. The domains with and without sulfur annealing were etched via H2 under the same conditions, and the changes of surface microstructures and properties were compared. It was found that the tolerance of MoS2 to H2 etching was enhanced after sulfur annealing. Results of the photoluminescence spectrum further proved that H2 etching could effectively detect the repair effect of sulfur vacancies. As a practical application, the optimum condition of sulfur annealing was obtained through H2 etching. Our work promotes the practical application of MoS2 in the field of new-generation electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

Published
2020
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