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1,291 results on '"Wang, Zhanhui"'

1. The role of shear flow collapse and enhanced turbulence spreading in edge cooling approaching the density limit

Author

Long, Ting, Diamond, PH, Ke, Rui, Chen, Zhipeng, Xu, Xin, Tian, Wenjing, Hong, Rongjie, Cao, Mingyun, Liu, Yanmin, Xu, Min, Wang, Lu, Yang, Zhoujun, Yuan, Jinbang, Zhou, Yongkang, Yan, Qinghao, Yang, Qinghu, Shen, Chengshuo, Nie, Lin, Wang, Zhanhui, Hao, Guangzhou, Wang, Nengchao, Chen, Zhongyong, Li, Jiquan, Chen, Wei, and Zhong, Wulyu

Subjects
Nuclear and Plasma Physics, Physical Sciences, tokamak, density limit, edge cooling, turbulence spreading, shear flow, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Fluids & Plasmas, Nuclear and plasma physics
Abstract

Experimental studies of the dynamics of shear flow and turbulence spreading at the edge of tokamak plasmas are reported. Scans of line-averaged density and plasma current are carried out while approaching the Greenwald density limit on the J-TEXT tokamak. In all scans, when the Greenwald fraction f G = n ¯ / n G = n ¯ / ( I p / π a 2 ) increases, a common feature of enhanced turbulence spreading and edge cooling is found. The result suggests that turbulence spreading is a good indicator of edge cooling, indeed better than turbulent particle transport is. The normalized turbulence spreading power increases significantly when the normalized E × B shearing rate decreases. This indicates that turbulence spreading becomes prominent when the shearing rate is weaker than the turbulence scattering rate. The asymmetry between positive/negative (blobs/holes) spreading events, turbulence spreading power and shear flow are discussed. These results elucidate the important effects of interaction between shear flow and turbulence spreading on plasma edge cooling.

Published
2024

2. Long radial coherence of electron temperature fluctuations in non-local transport in HL-2A plasmas

Author

Shi, Zhongbing, Fang, Kairui, Li, Jingchun, Zou, Xiaolan, Lu, Zhaoyang, Wen, Jie, Wang, Zhanhui, Ding, Xuantong, Chen, Wei, Yang, Zengchen, Ji, Min Jiang Xiaoquan, Tong, Ruihai, Li, Yonggao, Shi, Peiwang, Zhong, Wulyv, and Xu, Min

Subjects
Physics - Plasma Physics
Abstract

The dynamics of long-wavelength ($k_\theta<1.4 \mathrm{\ cm^{-1}}$), broadband (20-200 kHz) electron temperature fluctuations ($\tilde T_e/T_e$) of plasmas in gas-puff experiments were observed for the first time in HL-2A tokamak. In a relative low density ($n_e(0) \simeq 0.91 \sim 1.20 \times10^{19}/m^3$) scenario, after gas-puffing the core temperature increases and the edge temperature drops. On the contrary, temperature fluctuation drops at the core and increases at the edge. Analyses show the non-local emergence is accompanied with a long radial coherent length of turbulent fluctuations. While in a higher density ($n_e(0) \simeq 1.83 \sim 2.02 \times10^{19}/m^3$) scenario, the phenomena were not observed. Furthermore, compelling evidence indicates that $\textbf{E} \times \textbf{B}$ shear serves as a substantial contributor to this extensive radial interaction. This finding offers a direct explanatory link to the intriguing core-heating phenomenon witnessed within the realm of non-local transport.

Published
2023

4. On how structures convey non-diffusive turbulence spreading

Author

Long, Ting, Diamond, Patrick H, Ke, Rui, Chen, Zhipeng, Cao, Mingyun, Xu, Xin, Xu, Min, Hong, Rongjie, Tian, Wenjing, Yuan, Jinbang, Liu, Yanmin, Yan, Qinghao, Yang, Qinghu, Shen, Chengshuo, Guo, Weixin, Wang, Lu, Nie, Lin, Wang, Zhanhui, Hao, Guangzhou, Wang, Nengchao, Chen, Zhongyong, Pan, Yuan, Li, Jiquan, Chen, Wei, and Zhong, Wulyu

Subjects
Nuclear and Plasma Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Fluids & Plasmas, Nuclear and plasma physics
Abstract

Abstract: We report on comprehensive experimental studies of turbulence spreading in edge plasmas. These studies demonstrate the relation of turbulence spreading and entrainment to intermittent convective density fluctuation events or bursts (i.e. blobs and holes). The non-diffusive character of turbulence spreading is thus elucidated. The turbulence spreading velocity (or mean jet velocity) manifests a linear correlation with the skewness of density fluctuations, and increases with the auto-correlation time of density fluctuations. Turbulence spreading by positive density fluctuations is outward, while spreading by negative density fluctuations is inward. The degree of symmetry breaking between outward propagating blobs and inward propagating holes increases with the amplitude of density fluctuations. Thus, blob-hole asymmetry emerges as crucial to turbulence spreading. These results highlight the important role of intermittent convective events in conveying the spreading of turbulence, and constitute a fundamental challenge to existing diffusive models of spreading.

Published
2024

6. Parametric study of helicon wave current drive in CFETR

Author

Wu, Xianshu, Li, Jingchun, Chen, Jiale, Xu, Guosheng, Dong, Jiaqi, Wang, Zhanhui, Sun, Aiping, and zhong, Wulv

Subjects
Physics - Plasma Physics
Abstract

This paper evaluates the feasibility of helicon current drive (HCD) in a hybrid scenario for the China Fusion Engineering Test Reactor (CFETR). Utilizing the GENRAY/CQL3D package, a large number of simulations (over 5 000) were conducted, with parametric scans in the antenna's poloidal position, launched parallel refractive index, and wave frequency. The analysis reveals that helicon has excellent accessibility under reactor-level conditions, and smaller n|| and higher wave frequency result in enhanced wave absorption. The simulations demonstrate an optimal launched parallel refractive index of approximately 1.6 for the CFETR hybrid scenario. The best launch position is found to be within a poloidal angle range of 25 degrees to 65 degrees. Additionally, it is preferable to have a narrow parallel refractive index spectrum for wave absorption when operating below the threshold value of {\Delta}n|| (~0.6), beyond which the effect of {\Delta}n|| on wave absorption is negligible. This study provides valuable insights into the potential application of HCD in CFETR.

Published
2023

7. How turbulent transport broadens the heat flux width: local SOL production or edge turbulence spreading?

Author

Wu, Ting, Diamond, Patrick H, Nie, Lin, Xu, Min, Yu, Yi, Hong, Rongjie, Chen, YH, Xu, Jianqiang, Long, Ting, Zhang, Yi, Yan, Qinghao, Ke, Rui, Cheng, Jun, Li, Wei, Huang, Zhihui, Yan, Longwen, Chu, Xu, Wang, Zhanhui, and Hidalgo, Carlos

Subjects
Nuclear and Plasma Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Fluids & Plasmas, Nuclear and plasma physics
Abstract

Abstract: This paper uses data from limited HL-2A Ohmic-plasma to answer the question of how turbulent transport broadens the heat flux width. A key issue in this study is the determination of the origin of SOL turbulence. We develop the concept of the energy production ratio R_a, which compares the flux of turbulence energy across the LCFS to the net, integrated energy production in the SOL. The flux of turbulence energy (i.e., spreading) is measured directly, using Langmuir probes. Experimental data is used to evaluate R_a. Results show that usually R_a>1, indicating that SOL turbulence is energized primarily by edge turbulence spreading. The exceptions – cases where R_a

Published
2023

8. Precise isolation and structural origin of an ultra-specific nanobody against chemical compound

Author

Yang, Huijuan, Vasylieva, Natalia, Wang, Jiaxin, Li, Zhenfeng, Duan, Wenbo, Chen, Shuang, Wen, Kai, Meng, Hui, Yu, Xuezhi, Shen, Jianzhong, Hammock, Bruce D, and Wang, Zhanhui

Subjects
Medicinal and Biomolecular Chemistry, Chemical Sciences, Prevention, Biotechnology, Single-Domain Antibodies, Enzyme-Linked Immunosorbent Assay, Immunoassay, Indicators and Reagents, Nanobody, Ultra-specificity, Recognition mechanism, Accurate detection, Environmental Sciences, Engineering, Strategic, Defence & Security Studies, Chemical sciences, Environmental sciences
Abstract

Highly specific antibodies are the key reagents for developing immunoassays with a low false positive rate for environmental monitoring. Here, we provide evidence that nanobodies have the potential to achieve higher specificity than conventional antibodies and explain why from their structural features. Using sulfadimethoxine (SDM) as a model analyte, we constructed an immune phage display library and precisely isolated an ultra-specific nanobody (H1-17) by a crucial homologous antigen counter selection strategy. H1-17 showed no observable cross-reactivity (CR) with other structural analogs of 41 SDM tested, which has never been achieved by conventional antibodies. The structurally original specificity of H1-17 was illuminated and compared with that of one conventional antibody by homology modeling and site-directed mutagenesis validation. It was found that the noncanonical disulfide bond (C50-C104) of H1-17 helped CDR3 form a tailor-made binding pocket and divide it into two parts to accommodate the common structure of sulfonamides and the characteristic methoxyl group of SDM, respectively. Besides, the mutual-checking hydrogen bonds also played important roles in the specific recognition. Lastly, immunoassays with zero false positive rate were developed to screen SDM in water and milk samples, indicating that nanobodies could be reliable reagents for the accurate detection of chemical compounds.

Published
2023

26. Influence of Small Molecule Property on Antibody Response

Author

Wen, Kai, Bai, Yuchen, Wei, Yujie, Li, Chenglong, Zhang, Suxia, Shen, Jianzhong, and Wang, Zhanhui

Subjects
Quantitative Biology - Biomolecules
Abstract

Antibodies with high titer and affinity to small molecule are critical in the field for the development of vaccines against drugs of abuse, antidotes to toxins and immunoassays for compounds. However, little is known regarding how properties of small molecule influence and which chemical descriptor could indicate the degree of the antibody response. Based on our previous study, we designed and synthesized two groups of small molecules, called haptens, with varied hydrophobicities to investigate the relationship between properties of small molecules and antibody response in term of titer and affinity. We found that the magnitude of the antibody response is positively correlated with the degree of molecular hydrophobicity and related chemical descriptors. This study provides insight into the immunological characteristics of small molecules themselves and useful clues to produce high quality antibodies against small molecules.

Published
2020

44. Development of an immunoassay for the detection of carbaryl in cereals based on a camelid variable heavy‐chain antibody domain

Author

Liu, Zhiping, Wang, Kai, Wu, Sha, Wang, Zhanhui, Ding, Guochun, Hao, Xiujing, Li, Qing X, Li, Ji, Gee, Shirley J, Hammock, Bruce D, and Xu, Ting

Subjects
Agricultural, Veterinary and Food Sciences, Food Sciences, Animals, Camelids, New World, Carbaryl, Edible Grain, Enzyme-Linked Immunosorbent Assay, Food Contamination, Immunoglobulin Heavy Chains, Insecticides, Limit of Detection, Single-Chain Antibodies, Triticum, Zea mays, VHH, carbaryl, ELISA, cereals, food safety, Agricultural and Veterinary Sciences, Engineering, Food Science, Agricultural, veterinary and food sciences
Abstract

BackgroundThe variable domain of camelid heavy-chain antibodies (VHH) is increasingly being adapted to detect small molecules in various matrices. The insecticide carbaryl is widely used in agriculture while its residues have posed a threat to food safety and human health.ResultsVHHs specific for carbaryl were generated from an alpaca immunized with the hapten CBR1 coupled to keyhole limpet hemocyanin. An enzyme-linked immunosorbent assay (ELISA) based on the VHH C1 and the coating antigen CBR2-BSA was developed for the detection of carbaryl in cereals. This assay, using an optimized assay buffer (pH 6.5) containing 10% methanol and 0.8% NaCl, has a half-maximum signal inhibition concentration of 5.4 ng mL-1 and a limit of detection (LOD) of 0.3 ng mL-1 for carbaryl, and shows low cross reactivity (≤0.8%) with other tested carbamates. The LOD of carbaryl using the VHH-based ELISA was 36 ng g-1 in rice and maize and 72 ng g-1 in wheat. Recoveries of carbaryl in spiked rice, maize and wheat samples were in the range of 81-106%, 96-106% and 83-113%, respectively. Relative standard deviations of repeatability and intra-laboratory reproducibility were in the range of 0.8-9.2% and 2.9-9.7%, respectively.ConclusionThe VHH-based ELISA was highly effective in detecting carbaryl in cereal samples after simple sample extraction and dilution. © 2019 Society of Chemical Industry.

Published
2019

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