Lei Qi, Zhiyuan Shen, Jianjian Gao, Guoliang Zhao, Xiang Cui and Wei Kang
This paper aims to establish the wideband model of a sub-module in a modular multilevel converter (MMC) and analyze the switch transients of the sub-module.
Abstract
Purpose
This paper aims to establish the wideband model of a sub-module in a modular multilevel converter (MMC) and analyze the switch transients of the sub-module.
Design/methodology/approach
The paper builds an MMC sub-module test circuit and conducts dynamic tests both with and without the bypass thyristor. Then, it builds the wideband model of the MMC sub-module and extracts the model parameters. Finally, based on the wideband model, it simulates the switch transients and analyzes the oscillation mechanism.
Findings
The dynamic testing shows the bypass thyristor will add oscillations during switch transients, especially during the turn-on process. The thyristor acts like a small capacitor and reduces the total capacitor in the turn-on circuit loop, thus causing under-damped oscillations.
Originality/value
This paper found that the bypass thyristor will influence the MMC sub-module switch transients under certain circumstances. This paper proposes a partial inductance extraction procedure for the MMC sub-module and builds a wideband model of the sub-module. The wideband model is used to analyze and explain the switch transients, and can be further used for insulated gate bipolar transistor switch oscillation inhibition and sub-module design optimization.
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Expanding the research on traditional history of economic ideology into the research on the history of economics composed of three elements – history of ideology, history of…
Abstract
Purpose
Expanding the research on traditional history of economic ideology into the research on the history of economics composed of three elements – history of ideology, history of policies and events – is a new idea for researching the history of socialist political economy with Chinese characteristics. The start of the history of socialist political economy with Chinese characteristics is consistent with that of the Sinicization of Marxist political economy and can be dated from at least 1917.
Design/methodology/approach
The key point of the research on the history of ideologies of the socialist political economy with Chinese characteristics is to treat the relationship between theory and people properly, i.e. we should not neglect the effect brought out by the economists on theory construction while we attach importance to the theoretical contribution of the leaders and leading group of the Communist Party of China (CPC).
Findings
For the research on the history of economic policies of socialist political economy with Chinese characteristics, on the one hand, we should clarify the relationship among ideologies, strategies and policies; on the other hand, we should not evade the summarization of lessons from history.
Originality/value
Besides presenting the development route of socialist political economy with Chinese characteristics under competition, the research on the events in the history of socialist political economy with Chinese characteristics should also help develop the socialist political economy with Chinese characteristics.
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Xinjie Zhang, Fansen Kong, Zhiyuan Gu and Xiao Shen
FOV splicing optical remote sensing instruments have a strict requirement for the focal length consistency of the lens. In conventional optical-mechanical structure design, each…
Abstract
Purpose
FOV splicing optical remote sensing instruments have a strict requirement for the focal length consistency of the lens. In conventional optical-mechanical structure design, each optical element is equally distributed with high accuracy and everyone must have a high machining and assembly accuracy. For optical remote sensors with a large number of optical elements, this design brings great difficulties to lens manufacture and alignment.
Design/methodology/approach
Taking the relay lens in an optical remote sensing instrument with the field of view splicing as an example, errors of the system are redistributed to optical elements. Two optical elements, which have the greatest influence on modulation transfer function (MTF) of the system are mounted with high accuracy centering and the other elements are fixed by gland ring with common machining accuracy. The reduction ratio consistency difference among lenses is compensated by adjusting the optical spacing between the two elements.
Findings
Based on optical system simulation analysis, the optimized structure can compensate for the difference of reduction ratio among lens by grinding the washer thickness in the range of ±0.37 mm. The test data for the image quality of the lens show that the MTF value declined 0.043 within ±0.4 mm of space change between two barrels. The results indicate that the reduction ratio can be corrected by adjusting the washer thickness and the image quality will not obviously decline.
Originality/value
This paper confirms that this work is original and has not been published elsewhere nor is it currently under consideration for publication elsewhere. In this paper, the optimum structural design of the reduction relay lens for the field of view stitching applications is reported. The method of adjusting washer thickness is applied to compensate for the reduction ratio consistency difference of lenses. The optimized structure also greatly reduces the difficulty of lenses manufacture, alignment and improves the efficiency of assembly.
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Zhiyuan Wang, Jagdeep Singh-Ladhar and Howard Davey
This paper aims to examine the indirect tax reform process in China. Specifically, it examines the reform of business tax to value-added tax. Inefficiencies within the new tax…
Abstract
Purpose
This paper aims to examine the indirect tax reform process in China. Specifically, it examines the reform of business tax to value-added tax. Inefficiencies within the new tax system are identified and discussed. The “business tax to value-added tax” reform was seen as an essential element in promoting the economic transition and stimulating the service industries (Jin and Jin, 2013).
Design/methodology/approach
The paper uses archival and current literature. In undertaking the study, the different periods of indirect tax are examined, prior to 1994, 1994-2012, the changes from 2012 culminating in the new 2017 regime. Attributes of “good” value-added tax (VAT) systems are covered as well as a comparison with New Zealand’s goods and services tax (GST).
Findings
The paper finds that to align with the international trend of indirect tax development and more efficiently accomplish the economic transition China needs to build a more neutral VAT system with fewer reduced rates and exemptions and the tax system have created tax inefficiencies and increased the compliance cost. VAT is imposing an increasingly significant impact on China’s national economy and industrial structure as well as accountants.
Originality/value
This is the first study that analyses the indirect tax reforms that are currently being implemented in China and as such has lessons for China but also for VAT/GST in general. We should not forget how special New Zealand’s GST is and the clarity of focus of those who implemented it!
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Chen Weihong, Zhong Xi, Hailin Lan and Li Zhiyuan
In recent years, the phenomena of “accelerating” and “jumping” during the international expansion of Chinese enterprises have attracted a lot of attention from scholars. However…
Abstract
Purpose
In recent years, the phenomena of “accelerating” and “jumping” during the international expansion of Chinese enterprises have attracted a lot of attention from scholars. However, while a CEO’s career horizon can significantly affect his or her enterprise’s strategic decision-making, few studies have explored the role of CEO career horizon in terms of “accelerating” and “jumping” internationalization.
Design/methodology/approach
Based on a sample of China’s A-share listed manufacturing companies from 2008 to 2017, this study explores the impact of CEO career horizon on the internationalization pace and international rhythm of enterprises.
Findings
First, the shorter the CEO’s career horizon, the more likely the CEO can avoid risky strategic decisions, which ultimately causes a negative relationship between CEO career horizon and the internationalization pace and rhythm of the enterprise. Second, for larger and older boards of directors, there is a more negative impact of the CEO’s short-term career horizon on the internationalization pace and internationalization rhythm of the company. However, given a larger proportion of female directors and non-executive directors, the CEO’s short-term career horizon has a weaker negative impact on international pace and the rhythm of internationalization.
Originality/value
First, based on upper echelon theory, this study interprets the influence of CEO career horizon on the time dimension of corporate internationalization (including internationalization pace and international rhythm), deepening the theory’s explanatory power. Second, by clarifying the important predictive effect of CEO career horizon on internationalization pace and international rhythm, this research enriches extant research on both variables’ antecedents, as well as that on the influence of CEO career horizon. Finally, by introducing the regulatory role of the board’s supervisory ability, this study clarifies the boundary conditions for the influence of the CEO’s career horizon on international pace and rhythm, and it expands the literature on how CEOs and boards of directors can influence corporate strategic decisions during the internationalization process.
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Jiaxin Li, Zhiyuan Zhu, Zhiwei Li, Yonggang Zhao, Yun Lei, Xuping Su, Changjun Wu and Haoping Peng
Gallic acid is a substance that is widely found in nature. Initially, it was only used as a corrosion inhibitor to retard the rate of corrosion of metals. In recent years, with…
Abstract
Purpose
Gallic acid is a substance that is widely found in nature. Initially, it was only used as a corrosion inhibitor to retard the rate of corrosion of metals. In recent years, with intensive research by scholars, the modification of coatings containing gallic acid has become a hot topic in the field of metal protection. This study aims to summarize the various preparation methods of gallic acid and its research progress in corrosion inhibitors and coatings, as well as related studies using quantum chemical methods to assess the predicted corrosion inhibition effects and to systematically describe the prospects and current status of gallic acid applications in the field of metal corrosion inhibition and protection.
Design/methodology/approach
First, the various methods of preparation of gallic acid in industry are understood. Second, the corrosion inhibition principles and research progress of gallic acid as a metal corrosion inhibitor are presented. Then, the corrosion inhibition principles and research progress of gallic acid involved in the synthesis and modification of various rust conversion coatings, nano-coatings and organic resin coatings are described. After that, studies related to the evaluation and prediction of gallic acid corrosion inhibition on metals by quantum chemical methods are presented. Finally, new research ideas on gallic acid in the field of corrosion inhibition and protection of metals are summarized.
Findings
Gallic acid can be used as a corrosion inhibitor or coating in metal protection.
Research limitations/implications
There is a lack of research on the synergistic improvement of gallic acid and other substances.
Practical implications
The specific application of gallic acid in the field of metal protection was summarized, and the future research focus was put forward.
Originality/value
To the best of the authors’ knowledge, this paper systematically expounds on the research progress of gallic acid in the field of metal protection for the first time and provides new ideas and directions for future research.
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Debiao Meng, Shiyuan Yang, Chao He, Hongtao Wang, Zhiyuan Lv, Yipeng Guo and Peng Nie
As an advanced calculation methodology, reliability-based multidisciplinary design optimization (RBMDO) has been widely acknowledged for the design problems of modern complex…
Abstract
Purpose
As an advanced calculation methodology, reliability-based multidisciplinary design optimization (RBMDO) has been widely acknowledged for the design problems of modern complex engineering systems, not only because of the accurate evaluation of the impact of uncertain factors but also the relatively good balance between economy and safety of performance. However, with the increasing complexity of engineering technology, the proposed RBMDO method gradually cannot effectively solve the higher nonlinear coupled multidisciplinary uncertainty design optimization problems, which limits the engineering application of RBMDO. Many valuable works have been done in the RBMDO field in recent decades to tackle the above challenges. This study is to review these studies systematically, highlight the research opportunities and challenges, and attempt to guide future research efforts.
Design/methodology/approach
This study presents a comprehensive review of the RBMDO theory, mainly including the reliability analysis methods of different uncertainties and the decoupling strategies of RBMDO.
Findings
First, the multidisciplinary design optimization (MDO) preliminaries are given. The basic MDO concepts and the corresponding mathematical formulas are illustrated. Then, the procedures of three RBMDO methods with different reliability analysis strategies are introduced in detail. These RBMDO methods were proposed for the design optimization problems under different uncertainty types. Furtherly, an optimization problem for a certain operating condition of a turbine runner blade is introduced to illustrate the engineering application of the above method. Finally, three aspects of future challenges for RBMDO, namely, time-varying uncertainty analysis; high-precision surrogate models, and verification, validation and accreditation (VVA) for the model, are discussed followed by the conclusion.
Originality/value
The scope of this study is to introduce the RBMDO theory systematically. Three commonly used RBMDO-SORA methods are reviewed comprehensively, including the methods' general procedures and mathematical models.
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Shuqing Li, Zhiyuan Hao, Li Ding and Xia Xu
Through the case analysis of China’s digital library, the purpose of this paper is to make readers understand the development status, achievements and problems of China’s digital…
Abstract
Purpose
Through the case analysis of China’s digital library, the purpose of this paper is to make readers understand the development status, achievements and problems of China’s digital library. At the same time, it also enables readers to understand the common application forms of these modern information technologies in digital libraries, so as to provide a reference basis for the application of new technologies in other countries’ digital libraries.
Design/methodology/approach
On the basis of literature review, the authors have analyzed a conspicuous collection of related papers in order to make a comprehensive summary and elaboration on the present situation of modern information technology application in Chinese digital libraries.
Findings
This paper defines and analyses the concepts, contents and relationships of the three most important modern Big Data information technologies, and then completes the analysis of the current situation of the application of information technology in Chinese digital libraries. The block chain can achieve more accurate information collection, more secure information storage and more effective information dissemination. Artificial intelligence can improve the existing digital library service level in three aspects: resource construction, information organization and information service. Internet plus will help transform the traditional digital library business mode in order to adapt to the change of user-centered service.
Originality/value
This is among the first structured attempts of comprehensively and generally summarizing the application of modern information technology in Chinese digital libraries. It also contains an original exploration of the relationship between the main kinds of modern information technology. Based on this, a relatively complete application scenario and possible vision of modern information technology in digital library can be built.
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Yunli Bai, Tianhao Zhou, Zhiyuan Ma and Linxiu Zhang
The purpose of this paper is to examine the role of infrastructure on the income growth and poverty reduction of rural household in China by estimating the impact of road…
Abstract
Purpose
The purpose of this paper is to examine the role of infrastructure on the income growth and poverty reduction of rural household in China by estimating the impact of road accessibility on the extent of household off-farm employment and its heterogeneous effects among the groups with different income level and earning capacity.
Design/methodology/approach
Using nationally representative panel data collected in 100 villages about 2000 households across five provinces in 2005, 2008, 2012, 2016 and 2019. This study adopts Tobit model with panel data, zero-inflated Poisson model and static nonbalanced panel model to yield consistent results.
Findings
We find that road accessibility generally has no effect on the number of off-farm laborers and duration of off-farm employment. However, road accessibility is not beneficial for the households in the low-income villages or with low educational attainment, but it benefits the households in the high-income villages by promoting local off-farm employment or with high educational attainment by increasing the duration of migrant off-farm employment.
Originality/value
This study identifies the heterogeneous effects of road accessibility on the extent of off-farm employment among rural households, which narrows the research gap and enriches the literature. The empirical findings imply that road accessibility widens the gap between rich and poor in off-farm employment, which is of great important to the alleviation of relative poverty after 2020 in China.
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Jie Ma, Zhiyuan Hao and Mo Hu
The density peak clustering algorithm (DP) is proposed to identify cluster centers by two parameters, i.e. ρ value (local density) and δ value (the distance between a point and…
Abstract
Purpose
The density peak clustering algorithm (DP) is proposed to identify cluster centers by two parameters, i.e. ρ value (local density) and δ value (the distance between a point and another point with a higher ρ value). According to the center-identifying principle of the DP, the potential cluster centers should have a higher ρ value and a higher δ value than other points. However, this principle may limit the DP from identifying some categories with multi-centers or the centers in lower-density regions. In addition, the improper assignment strategy of the DP could cause a wrong assignment result for the non-center points. This paper aims to address the aforementioned issues and improve the clustering performance of the DP.
Design/methodology/approach
First, to identify as many potential cluster centers as possible, the authors construct a point-domain by introducing the pinhole imaging strategy to extend the searching range of the potential cluster centers. Second, they design different novel calculation methods for calculating the domain distance, point-domain density and domain similarity. Third, they adopt domain similarity to achieve the domain merging process and optimize the final clustering results.
Findings
The experimental results on analyzing 12 synthetic data sets and 12 real-world data sets show that two-stage density peak clustering based on multi-strategy optimization (TMsDP) outperforms the DP and other state-of-the-art algorithms.
Originality/value
The authors propose a novel DP-based clustering method, i.e. TMsDP, and transform the relationship between points into that between domains to ultimately further optimize the clustering performance of the DP.