Search

Your search keyword '"ZHANG Wei-wei"' showing total 1,974 results
Start Over Author "ZHANG Wei-wei"

Refine your results

more »

more »

more »

more »

more »
1,974 results on '"ZHANG Wei-wei"'

202. Simultaneous determination of 20 kinds of mycotoxins in maize straw feed by QuEChERS-ultra performance liquid chromatography-triple quadrupole mass spectrometry.

Author

LIU Ting-ting, ZHANG Wei-wei, SHI Xiao-mei, ZHAI Chen, HU Li-ming, QIAN Chen-jing, and ZHANG Xiao-lin

Subjects
*MYCOTOXINS, *MASS spectrometry, *QUADRUPOLES, *MEMBRANE filters, *STANDARD deviations, *CORNSTALKS
Abstract

The experiment was to establish an analytical method for the simultaneous determination of 20 kinds of mycotoxins in maize straw feed by QuEChERS-UPLC-MS/MS. The samples were extracted with acetonitrile-acetic acid (95 : 5), and the supernatant was purified by anhydrous MgSO4, PSA and C18. Then an appropriate amount of supernatant was blown to dry with nitrogen. The samples were reconstituted with methanol-water-acetic acid (30 : 70 : 0.1), passed through a PTFE filter membrane, and separated on a C18 chromatographic column. Using the multiple reaction monitoring (MRM) scan mode to monitor the target compounds and the results were quantified by the external standard method. The results showed that the linear ranges of the 20 mycotoxins were good, and the correlation coefficients (R²) were greater than 0.99. The limits of detection were 0.15~3.10 µg/kg, with limits of quantification were 0.49~10.33 µg/kg. The recoveries at the three levels were within the range of 70.4%~118.3%, with relative standard deviations of 1%~10% (n=6). The study indicates that the method was easy to operate, reproducible and highly accurated and sensitive, which can be used for routine screening of mycotoxins in corn stalk feed. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

203. Synthesis and Application of Terminated Polyhydroxystearate Aliphatic Amine Hyperdispersant.

Author

GE Tie-jun, MA Hao-ran, ZHU Xi-hua, JIANG Yong, ZHANG Wei-wei, and TANG Kai-hong

Subjects
ALIPHATIC amines, ACRYLONITRILE butadiene styrene resins, CARBON-black, SCANNING electron microscopes, IMPACT strength, FLEXURAL strength
Abstract

Poly(12-hydroxystearate) was prepared by polycondensation. Palmitic acid, 3-dimethylaminopropylamine and poly(12-hydroxystearate) were reacted to form a terminated polyhydroxystearate aliphatic amine (HTPF) hyperdispersant. The structure of the product was characterized by IR and ¹H NMR. The dispersion effect of HTPF on carbon black was analyzed by sedimentation experiment and scanning electron microscope. HTPF was added into ABS/carbon black masterbatch, and the effects of the amount of HTPF on the rheological and mechanical properties of ABS/carbon black masterbatch were studied. The results show that the loss modulus and storage modulus of the composites decrease gradually with the increase of HTPF content compared with the pure masterbatch, and the composites appear shear thinning behavior. With the increase of HTPF content, the mechanical properties of the composites gradually improved. When the content of HTPF is 40%, the tensile strength and impact strength of the composite reach the maximum of 45.9 MPa and 8.54 kJ/m²; When the content of HTPF is 50%, the flexural strength of the composites reaches 80.22 MPa. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

204. Box Jenkins Neural Network Keynecian Reinforcement Learning Based Financial Big Data Analysis for Optimal Prediction

Author

Zhang Wei Wei and P. Pushpa P

Abstract

In the digital era, Economic and Finance information is huge and attainable. The financial industry is a key to stimulating the evolution of the national economy, and with the immense availability of huge data makes the process of financial data analysis both a time consuming and tedious decision making in the financial market. By analyzing this Economic and Finance information significantly and easily, valuable perceptions can be provided. For rational economic growth, information pertaining to economic affairs and likelihoods is critical to decision-makers like governmental bodies, financial institutions and banks. However, precise predictions have been demand owing to the intricacy and unpredictability of financial and economic systems in the midst of persistent changes in economic environments. This work provides to approaches for better economic prediction and decision-making using a novel method called, Multivariate Box Jenkins Neural Network-based Keynecian Reinforcement Learning (MBJNN-KRL). In this work, Financial Data Analysis Deep Economic Prediction model that contains a Multivariate Box Jenkins Long Short Term Memory Forecasting model, for better economic prediction and convergence speed even in case of large data is first designed. The deep reinforcement learning technique is then adapted to retrain neural networks and rebalance the aggregate expenditure periodically. We combined the multivariate Multivariate Box Jenkins Long Short Term Memory Forecasting and the Keynecian Reinforcement Learning models into a single integrated reinforcement learning model named Multivariate Box Jenkins Neural Network-based Keynecian Reinforcement Learning (MBJNN-KRL). Finally, distinct sets of experiments are carried out on real large-scale data set, and the results entirely prove the efficiency and robustness of the proposed method in arbitrary economic prediction based on financial data. Our empirical data revealed that the MBJNN-KRL method could attain combative financial performance compared to traditional methods in terms of predictive accuracy, convergence speed and prediction error.

Published
2022
Full Text
View/download PDF

222. Associations of multiple visual rating scales based on structural magnetic resonance imaging with disease severity and cerebrospinal fluid biomarkers in patients with Alzheimer’s disease

Author

Wan, Mei-dan, primary, Liu, Hui, additional, Liu, Xi-xi, additional, Zhang, Wei-wei, additional, Xiao, Xue-wen, additional, Zhang, Si-zhe, additional, Jiang, Ya-ling, additional, Zhou, Hui, additional, Liao, Xin-xin, additional, Zhou, Ya-fang, additional, Tang, Bei-sha, additional, Wang, Jun-Ling, additional, Guo, Ji-feng, additional, Jiao, Bin, additional, and Shen, Lu, additional

Published
2022
Full Text
View/download PDF

224. Determining the impact of Covid-19 on the business norms and performance of SMEs in China

Author

Sun, Tiezhu, Zhang, Wei-Wei, Sorin Dinca, Marius, Raza, Muhammad, Sun, Tiezhu, Zhang, Wei-Wei, Sorin Dinca, Marius, and Raza, Muhammad

Abstract

This study’s key purpose was to examine the impact of COVID-19 on SMEs’ business norms and performance in China. The primary quantitative data have been collected through a survey questionnaire based on 330 participants. For analyzing the collected data, the use of the SEM technique has been made in this study. The researcher has adopted the data from the managers and employees belonging to the SMEs in China who are the research respondents. The data has been gathered from a sample size of 330. The number of distributed questionnaires was 340, whereas the responses gained were nearly 335, out of which 330 responses were selected. In the SEM technique, a CFA test was conducted to confirm the model’s reliability and validity, whereas the results of path assessment were presented to examine the association between the variables. The findings of this study have confirmed the significant impact of COVID-19 on innovative operational procedures, profitability, remote work, and stakeholder satisfaction and safety.

Published
2022

225. COVID-19 and international trade: insights and policy challenges in China and USA

Author

Zhang, Wei-Wei, Dawei, Wang, Majeed, Muhammad Tariq, Sohail, Sidra, Zhang, Wei-Wei, Dawei, Wang, Majeed, Muhammad Tariq, and Sohail, Sidra

Abstract

Like the other spheres of economic activity, international trade is also a victim of the current Covid-19 pandemic. Therefore, taking this into consideration, this study examines the impact of the novel Covid-19 virus on international trade, by using monthly data from China and USA. For this purpose, we have referred to the novel Fourier causality test. The findings of the test show that there is a direct causal relationship between the Covid-19 related deaths and the exports and imports of China, while the Covid-19 cases do not have a causal relationship with the exports and imports of China in the pandemic. Moreover, the Covid-19 cases and deaths have a causal relationship with the exports and imports of USA. Thus, we found that there were heterogeneous effects experienced in both the countries. Based on these empirical findings, some policy implications have been suggested for the Chinese and USA economies.

Published
2022

237. Diversification of the phytophagous lineages of true bugs (Insecta: Hemiptera: Heteroptera) shortly after that of the flowering plants

Author

Ye, Fei, primary, Kment, Petr, additional, Rédei, Dávid, additional, Luo, Jiu‐Yang, additional, Wang, Yan‐Hui, additional, Kuechler, Stefan M., additional, Zhang, Wei‐Wei, additional, Chen, Ping‐Ping, additional, Wu, Hao‐Yang, additional, Wu, Yan‐Zhuo, additional, Sun, Xiao‐Ya, additional, Ding, Lu, additional, Wang, Yue‐Ran, additional, and Xie, Qiang, additional

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results