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1,334 results on '"Zhao, Guodong"'

211. Key Factors of Effecting Blended Learning Satisfaction: A Study on Peking University Students

Author

Zhao, Guodong, Yuan, Shuai, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Tsang, Philip, editor, Cheung, Simon K. S., editor, Lee, Victor S. K., editor, and Huang, Ronghuai, editor

Published
2010
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215. Scheduling the operations of a double-load crane in slab yards.

Author

Zhao, Guodong, Liu, Jiyin, and Dong, Yun

Subjects
CRANES (Machinery), MIXED integer linear programming
Abstract

This paper studies a double-load crane scheduling problem (DLCSP) in steel slab yards. A slab yard stores slabs in stacks. To prepare for use in production, some slabs need to be moved from one place to another. These movement tasks are performed by a double-load crane which can hold up to two slabs simultaneously. Given a set of tasks and possibly precedence relationships among them, the scheduling problem is to allocate the tasks to double-load operations and determine the schedule for the crane to perform the tasks so as to minimise the makespan. The problem is first formulated as a mixed integer linear programming (MILP) model with variables representing the order of tasks. Based on properties of the problem, it is then reformulated from a crane operation perspective. Computational experiments are carried out on practical data collected from a steel company. The results show that both models can solve practical sized problems optimally, with the second model being more efficient. [ABSTRACT FROM AUTHOR]

Published
2020
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217. Performance Analysis of a Coreless Axial-Flux PMSM by an Improved Magnetic Equivalent Circuit Model

Author

Xiangdong Liu, Jing Zhao, Ning Dong, Tongkai Ma, and Zhao Guodong

Subjects
Physics, Mechanical load, Stator, business.industry, Rotor (electric), Magnetic flux leakage, Energy Engineering and Power Technology, Structural engineering, Counter-electromotive force, Finite element method, law.invention, law, Voltage source, Electrical and Electronic Engineering, Synchronous motor, business
Abstract

In this paper, an improved magnetic equivalent circuit (MEC) model of a coreless axial-flux permanent-magnet synchronous machine (AFPMSM) with printed circuit board (PCB) winding is presented, which considers the curvature effect, fringing effect, leakage flux, and rotor yoke's magnetic saturation. The axial air-gap flux density distribution, no-load back electromotive force, winding inductances, and electromagnetic torque are predicted by the proposed MEC model. The steady-state performances of the machine under heavy load, as well as the dynamic response of the machine with a connected voltage source and mechanical load, are calculated. All the results obtained from the proposed model are in good agreement with those issued from the 3D finite element method (FEM). The computation time of the proposed model is greatly reduced compared to 3D FEM. Finally, a coreless AFPMSM prototype with a PCB stator is manufactured, and experiments are carried out to verify the predicted results.

Published
2021
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232. From E-Campus to E-Learning: An Overview of ICT Applications in Chinese Higher Education

Author

Zhao, Guodong and Jiang, Zhongjiao

Abstract

Centring on the application of information and communication technology (ICT) in Chinese higher education, this paper discusses the development of e-campus in Chinese universities from three different aspects: campus network infrastructure and various management information systems; three modes of e-learning and its application in higher education institutions; and educational digital resources sharing. Finally, problems encountered during the application of ICT in Chinese higher education and possible solutions are also presented.

Published
2010
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234. Fenton-like chemistry enables catalytic oxidative desulfurization of thioacetals and thioketals with hydrogen peroxide

Author

Zhao, Guodong, Wang, Yaxin, Wang, Cheng, Lei, Haimin, Yi, Bingqing, Tong, Rongbiao, Zhao, Guodong, Wang, Yaxin, Wang, Cheng, Lei, Haimin, Yi, Bingqing, and Tong, Rongbiao

Abstract

(di-)Thioacetals and (di-)thioketals serve commonly as protecting groups of carbonyls and alcohols in organic synthesis, and therefore require highly efficient and chemoselective methods for desulfurization into carbonyls or alcohols. Although many approaches have been developed for such deprotection reactions, they usually employ toxic and/or expensive reagents under harsh conditions with a relatively long reaction time. Reported is a green catalytic approach that exploits Fenton-like chemistry (FLC: CeBr3-H2O2) for the oxidative desulfurization of thioacetals and thioketals, which has many competitive advantages including (1) high efficiency (15 min, up to 97% yield), (2) high chemoselectivity with broad substrate scope, (3) greenness (H2O as the sole waste) with outstanding green chemistry metrics, and (4) low cost. Detailed mechanistic studies revealed that the reactive brominating species (RBS, HOBr) generated in situ using Fenton-like chemistry (i.e., HO) and bromide reacted with sulfide (thioacetals or thioketals) to form the bromosulfonium intermediate (RR'S-Br), which was attacked by a heteroatom such as sulfur, oxygen or nitrogen to initiate the hydrolysis to carbonyls or alcohols. The released bromide ion (Br-) could be oxidized again by Fenton-like chemistry to generate RBS for the next catalytic cycle. This highly efficient, chemoselective, and green approach for oxidative desulfurization is expected to find wide applications in organic synthesis.

Published
2022

236. One-Pot Carbon-Chain Extension for Nervonic/Carboxylic Acid Synthesis with the Assistance of Microwaves and Lithium Chloride.

Author

Wang, Cheng, Su, Jin, Li, Yimeng, Gao, Shengfang, Huo, Xiaojie, Yi, Bingqing, Zhao, Guodong, and Lei, Haimin

Subjects
LITHIUM chloride, MICROWAVES, CARBOXYLIC acids, NATURAL products, SAPONIFICATION, MICROWAVE heating
Abstract

A mild, green, and convenient synthesis of nervonic acid was developed through a one-pot carbon-chain extension with the assistance of microwaves and lithium chloride (55% total yield); this is preferable to a previous six-step method (10% total yield). Compared with the previous lengthy refluxing process (>80 hours) with corrosive reagents, which furnished a mixture of cis - and trans -isomers, this efficient microwave protocol was more than a hundred times faster and was free of configurational isomerization. Notably, LiCl played a dual role in a Krapcho decarboxylation and subsequent ester hydrolysis under neutral conditions that replace the corrosive saponification in the previously reported one-pot method. Finally, this mild and efficient protocol was successfully applied to various carboxylic acids, including natural products, verifying its wide utility, easy operations, and attractive properties in organic synthesis. [ABSTRACT FROM AUTHOR]

Published
2023
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237. Real‐world application of a fast stool DNA test for colorectal cancer screening in primary screening positive population.

Author

Zhu, Yunfeng, Zhao, Guodong, Ma, Weihua, Chen, Xinmin, Chen, Xiaofei, Li, Danning, Zhao, Shuyan, Xiong, Shangmin, and Zheng, Minxue

Subjects
*EARLY detection of cancer, *MEDICAL screening, *DNA, *CHINESE people, *COLORECTAL cancer
Abstract

Background: Stool DNA test has been emerged as an effective noninvasive method for colorectal cancer (CRC) screening, but the real‐world performance of stool DNA test in Chinese population has rarely been reported. Methods: A total of 36,527 subjects were recruited in Haining City from January 2021 to December 2021. Participants underwent primary screening by taking both two‐samples fecal immunochemical tests (FITs) and high‐risk factor questionnaire (HRFQ), and those who tested either positive by FITs or evaluated to be high risk by HRFQ were recommended to undertake subsequent stool DNA test and colonoscopy. Results: Of 36,527 participants, 34,778 (95%) completed both HRFQ and FITs, 9947 (29%) showed positive results during primary screening, and the colonoscopy compliance rate was 49%. Of primary screening positives, 8733 (88%) completed stool sample collections, and colonoscopy results from 4293 eligible participants were used for analyzing the performance of stool DNA test. The sensitivities for detecting CRC and advanced adenomas (AA) were 100% (95% CI: 60–100%) and 40% (95% CI: 34–46%), and the area under curve (AUC) was 0.961 (95% CI:0.954–0.967) and 0.625 (95% CI: 0.609–0.641), respectively. The specificity of stool DNA test was 84% (95% CI: 82–85%). The false‐positive rate for stool DNA test is about 10% less than that of primary screening. Conclusion: Stool DNA test is a cost‐effective and promising alternative strategy for CRC screening in China. [ABSTRACT FROM AUTHOR]

Published
2023
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242. Reducing Postoperative Recurrence of Early‐Stage Hepatocellular Carcinoma by a Wound‐Targeted Nanodrug

Author

li, Bozhao, primary, Zhang, Xiuping, additional, Wu, Zhouliang, additional, Chu, Tianjiao, additional, Yang, Zhenlin, additional, Xu, Shuai, additional, Wu, Suying, additional, Qie, Yunkai, additional, Lu, Zefang, additional, Qi, Feilong, additional, Hu, Minggen, additional, Zhao, Guodong, additional, Wei, Jingyan, additional, Zhao, Yuliang, additional, Nie, Guangjun, additional, Meng, Huan, additional, Liu, Rong, additional, and Li, Suping, additional

Published
2022
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245. Conclusions

Author

Zhao, Guodong, primary, Zhang, Wei, additional, and Li, Shaoqian, additional

Published
2016
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247. Introduction

Author

Zhao, Guodong, primary, Zhang, Wei, additional, and Li, Shaoqian, additional

Published
2016
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249. Simulations and Experiments Toward Continuous Wave 167 nm Laser Generation for ARPES With High Energy Resolution

Author

Zhang, Ziyue, Han, Hainian, Zhao, Guodong, Liu, Guodong, Zhou, Xingjiang, and Wei, Zhiyi

Subjects
Materials Science (miscellaneous), Biophysics, General Physics and Astronomy, Physical and Theoretical Chemistry, Mathematical Physics
Abstract

Continuous wave (CW) laser at a vacuum ultraviolet (VUV) range with the narrow-linewidth is an ideal optical source in angle-resolved photoemission spectroscopy (ARPES) for the research of superconductors with a narrow band gap. In this study, we present an eighth-harmonic-generation (EHG) laser scheme for CW laser generation at the VUV range, in particular at 167.75 nm, based on the cascaded power enhancement cavities. An intracavity second-harmonic generation (ICSHG) 671 nm laser with the narrow-linewidth and active frequency stabilization is built as the first stage, delivering the 2.55 W output power. A resonant cavity for fourth-harmonic-generation (FHG) constitutes the second stage, which generates the 335.5 nm laser with the output power of up to 1.25 W. The third stage is designed for the EHG of 167.75 nm based on the KBBF crystal. To realize the efficient CW laser generation at 167.75 nm, a theoretical analysis concerning the enhancement factor and the conversion efficiency of the KBBF-based EHG is carried out. The results show that it is possible for mW-level 167.75 nm generation if the transmittance of the KBBF prism-coupled device is increased to 97%. A 59 W circular intracavity power is observed in the 335.5 nm enhanced cavity experiments, corresponding to the peak power density of up to 20.86 MW/cm2. This work paves a solid way for CW VUV laser generation with the narrow-linewidth, which would be an ideal tool for the extremely high resolution ARPES.

Published
2022
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