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Abstract Modulation strategy plays an important role in the good performance of modular multilevel converter (MMC). Since MMC has a special structure as well as a large number of submodules (SMs), it is almost impossible to apply the conventional multilevel space vector modulation (SVM) algorithm in it. In this study, a simplified SVM implementation method is proposed by grouping SMs. With the presented method, the high‐level SVM process for MMC can be easily done by implementing multiple two‐level or three‐level SVM algorithm, while the complicated offline or online efforts/tasks about mapping switching states or sequences in the conventional multilevel SVM are not necessary any more. In order to improve the harmonic characteristics, the sampling time of different subunits (SUs), each of which is formed by grouping a few SMs, is staggered evenly, which helps to achieve a higher equivalent switching frequency and less low‐order harmonics. Further, the capacitor voltage balance of SMs is improved by rotation strategies between SUs or inside each SU even without any capacitor voltage detecting or sorting. Since the presented method is independent of the number of SMs, it can be very easily expanded into a high‐level MMC. These propositions are verified by experiment.

Modular multilevel converter (MMC) is distinguished by its modularity. In order to improve its reliability and avoid unscheduled maintenance, it requires the MMC to continue operating even though some of its submodules (SMs) have failed. In this paper, a grouping management method of SMs in MMC is first presented where every six SMs are conceptually grouped into a virtual subunit (SU), and on this basis, a simplified space vector modulation (SVM) implementation is developed. Then, the fault-tolerant solutions are proposed by investigating the post-fault operation of the MMC based on the virtual SU concept. It is analyzed that the SU failures can be categorized into three basic types, according to the phase where the failed SMs are located, and also multiple SM failures can be decomposed into one or multiple basic fault types. In this way, the fault-tolerant solutions are unified regardless of the number of faulty SMs. Further, the sorting capacitor voltage control is combined into the proposed methods to balance all of the SM capacitor voltages. With the proposed fault-tolerant method, the amplitude and THD of the line voltages are almost unchanged under fault conditions when compared with normal operations. The simulation and experiment verify the propositions.

Based on generalized Riccati transformation and some inequalities, some oscillation results are established for a class of nonlinear fractional difference equations with damping term. An example is given to illustrate the validity of the established results.

The region of HR1 that binds to HR2 by a series of biochemical and biophysical measures is investigated. It shows the construction homology model for severe acute respiratory syndrome (SARS) coronavirus fusion core based on biochemical analysis and determines the mouse hepatitis virus (MHV) fusion core structure.

Vocabulary is one of the three elements of language, the building material and the basic of language. To communicate with others fluently, the first premise is that we must have a certain amount of vocabularies. Facing so many words to learn, it's necessary to investigate the vocabulary leaning strategies. The paper mainly studies the strategies of English vocabulary learning. Firstly it introduces the importance of vocabulary learning. Secondly, it explains the significance and purpose of the study, and does the survey to the current problems of students' vocabulary learning. Thirdly, it gives the definition and classification about the vocabulary learning strategies. Then, in the paper some factors which affect the strategies of vocabulary learning are listed. Finally, it points out the specific strategies of vocabulary learning and gets some opinion about it. It is hoped that this paper can offer some help for students' English vocabulary learning, and expand students' vocabulary. Also, it can improve students' interest in vocabulary learning and make vocabulary learning easy. [ABSTRACT FROM AUTHOR]

Advertising plays a vital role in the development of society and economy. Its function can not be underestimated. Advertising language is a special applying language when it compares with others like literary and technological languages. It has become an indispensable part of daily life because of its particular characteristics. It makes a brief introduction into the definition, function of advertising at first in this paper. Then, it mainly summarizes and analyzes the linguistics characteristics of cosmetic advertisements at lexical, rhetorical levels and sentence structure. Through the analysis of cosmetic advertisements, the linguistic features of advertisements are summarized. It is important for people to understand the beauty of language in advertisements. [ABSTRACT FROM AUTHOR]

Movie titles are films' eyes, having double effect of art appreciation and commercial advertisement, and directly playing the role of guidance and promotion. Good film names could convey the films' content as well as arouse audience's interest to get great box. With the continuous development of international cultural exchanges, film begins to get the attention of every nation increasingly as an important media in cultural exchange. With the opening of the Chinese market, we have more and more English movies. The Chinese audiences need to understand the movie titles before they enjoy the movies. But due to different cultural traditions, contexts, customs and thinking modes between the western and eastern world, the choices of their film names embodies distinctive cultural features. Movie titles convey the story to the audience to attract them. This requires the translation of movie titles to be accurate and embody the commercial values. This paper analyzes the translation strategies of English movie titles and explores a new strategy according to previous research results and research methods. This paper introduces the definition of translation strategies and some features of English movie titles and functions. Then it describes the principles of English movie titles translation and points out the translation strategies of English film titles. It is hoped that the context can help people to realize the necessity of proper translation of English movie titles, and accordingly promote the development of films in international market. [ABSTRACT FROM AUTHOR]

Higher power applications require a multilevel converter to meet high power ratings. A multimodule current-source converter (CSC) can provide a multilevel current waveforms and at the same time eliminate the bulky transformer at the ac side. However, it is required for the multimodule CSC to use multiple dc-link inductors for the purpose of power balance among different modules. Thus, one key issue in the design of the multimodule CSC is to balance the current through different dc-link inductors. This paper focuses on studying the control strategy of the multimodule CSC and a generalized current balancing method is presented. As presented, zero vectors are distributed based on the deviation of the dc-link inductor currents and the comparison of the capacitor voltages. Therefore, the current imbalance problems, not only those among the upper inductors but also those among the lower inductors are solved. Moreover, since the current balancing algorithm is not dependent on module numbers, the presented control strategy is very suitable for modularization. Especially, with the feedback of the capacitor voltages, the resonance arising from the inductor-capacitor (LC) filter is damped. In addition, a design method of the dc-link inductors is also derived. Finally, simulation and experimental results show the validity of the propositions. [ABSTRACT FROM AUTHOR]

This paper aims to explore the pulsewidthmodulation (PWM) schemes for three-phase current source converter, and a generic six-step direct PWM (SS-DPWM) scheme is proposed. In the SS-DPWM, one line cycle is divided into six 60° intervals, so called as "six-step." During each interval, only two of the three references, referred to as the Master and Slave references, respectively, compare with the carriers to directly generate the required switching patterns instead of using the transformation from bilogic signals to trilogic ones, as used in the conventional sinusoidal PWM (SPWM). In this paper, the variety of the Slave reference for each interval is identified, and many sets of modulating waveforms are presented for the SS-DPWM, resulting in very flexible and expanded modulations. The mechanism of the SS-DPWM is also presented to develop itsmodulating characteristics, and it is shown that, comparing with the conventional SPWM, the SS-DPWM has lower switching frequency, higher dc current utilization ratio, and in-phase transfer between the line currents and their references. A prototype has been built in the lab and the validity of the theoretical analysis is verified by the experimental results. [ABSTRACT FROM AUTHOR]

This paper examines the representation of Bai ethnicity based on a video made by a local Bai cameraman for temple carers. Presenting this video as a case of identity construction, this article deals with how a locally made video functions as a constructive tool which allows the cameraman and the locals, to some extent, to reproduce Bai ethnicity. In this case, the camera in 'native' hands is not used to visualise anthropology. The commonality between an independent video-making agenda and one that is geared toward anthropological inquiry challenges us to ponder if it is essential to distinguish between films made by anthropologists or the 'natives' that represent who they/we are. [ABSTRACT FROM AUTHOR]

This paper examines the construction of Bai ethnicity and Bai identity on the tourist market in Dali, Dali Bai Autonomous Prefecture, Yunnan, China. Focusing on how the social landscape of Dali has changed in response to the development of tourism, this paper explores how Bai ethnicity is advocated as a product loaded with potential economic values. The author discovers that 'commerce of authenticity' (T. Oakes, Tourism and modernity in China. London, Routledge, 1998), and different forms of ethnicity and artefacts promoted in the tourist market have not drowned out the sense of being ethnically Bai. Instead, the tourist industry has become a daily reminder of ethnicity to both insiders and outsiders by making people more self-conscious and reflexive about the 'cultural stuff' that they may have previously taken for granted, or may have left unattended. This paper demonstrates how locals actively appropriate state-defined categories and reshape them into the repertoire they desire. [ABSTRACT FROM AUTHOR]

Highly conserved heptad-repeat (HR1 and HR2) regions in class I viral fusion (F) proteins, including the F protein from paramyxovirus, interact with each other post-fusion to form a six-helix bundle called a fusion core. Crystals of the fusion core of Nipah virus have been grown at 291 Kusing PEG 4000 as precipitant. The diffraction pattern of the crystal extends to 2.1 Å resolution at 100 K in-house. The crystals have unit-cell parameters a = 31.664, b = 31.725, c = 51.256 Å, α = 80.706, β = 86.343, γ = 65.812° and belong to space group P1. Crystals of the fusion core of Hendra virus have also been grown at 291 K using PEG 4000 as precipitant. The diffraction pattern of the crystal extends to 2.0 Å resolution at 100 K in-house. A selenomethionine (SeMet) derivative of the HeV fusion core was overexpressed using the same Escherichia coli expression system and purified. The derivative crystals were obtained under similar conditions and three different wavelength data sets were collected to 2.0 Å resolution from the derivative crystal at BSRF (Beijing Synchrotron Radiation Facility). The crystals have unit-cell parameters a = 31.997, b = 31.970, c = 53.865 Å, α = 85.990, β = 85.842, γ = 68.245° and belong to space group P1. [ABSTRACT FROM AUTHOR]

The aetiological agent of an emergent outbreak of atypical pneumonia, severe acute respiratory syndrome (SARS), is a positive-stranded RNA virus (SARS-CoV) belonging to the Coronaviridae family with a genome that differs substantially from those of other known coronaviruses. Highly conserved heptad-repeat (HR1 and HR2) regions in class I viral fusion proteins, including spike protein from SARS coronavirus, interact with each other to form a six-helix bundle, which is called a fusion core. The crystal structure of the fusion core is expected to greatly facilitate drug design. Crystals of the fusion core of SARS-CoV spike protein have been grown at 291 K using PEG 4000 as precipitant. The diffraction pattern of the crystal extends to 2.8 Å resolution at 100 K in-house. The crystals have unit-cell parameters a = 121.2, b = 66.3, c = 70.0 Å , α = γ = 90, β = 107.4° and belong to space group C2. Assuming the presence of six molecules per asymmetric unit, the solvent content is estimated to be about 28%. [ABSTRACT FROM AUTHOR]

Crystals of a 2-Helix fusion-core construct of MHV spike protein (commonly referred to as E2) have been grown at 291 K using PEG 4000 as precipitant. The diffraction pattern of the crystal extends to 2.8 Å resolution at 100 K in-house. Furthermore, a selenomethionine (SeMet) derivative of MHV spike protein fusion core has been overexpressed and purified. The derivative crystals were obtained under similar conditions and three different wavelength data sets were collected to 2.4 Å resolution from a single derivative crystal at BSRF (Beijing Synchrotron Radiation Facility). The crystals have unit-cell parameters a = b = 48.3, c = 199.6 Å, α = β = 90, γ = 120° and belong to space group R3. Assuming the presence of two molecules in the asymmetric unit, the solvent content is calculated to be about 46%. [ABSTRACT FROM AUTHOR]

The surface transmembrane glycoprotein is responsible for mediating virion attachment to cell and subsequent virus-cell membrane fusion. However, the molecular mechanisms for the viral entry of coronaviruses remain poorly understood. The crystal structure of the fusion core of mouse hepatitis virus S protein, which represents the first fusion core structure of any coronavirus, reveals a central hydrophobic coiled coil trimer surrounded by three helices in an oblique, antiparallel manner. This structure shares significant similarity with both the low pH-induced conformation of influenza hemagglutinin and fusion core of HIV gp41, indicating that the structure represents a fusion-active state formed after several conformational changes. Our results also indicate that the mechanisms for the viral fusion of coronaviruses are similar to those of influenza virus and HIV. The coiled coil structure has unique features, which are different from other viral fusion cores. Highly conserved heptad repeat 1 (HR1) and HR2 regions in coronavirus spike proteins indicate a similar three-dimensional structure among these fusion cores and common mechanisms for the viral fusion. We have proposed the binding regions of HR1 and HR2 of other coronaviruses and a structure model of their fusion core based on our mouse hepatitis virus fusion core structure and sequence alignment. Drug discovery strategies aimed at inhibiting viral entry by blocking hairpin formation may be applied to the inhibition of a number of emerging infectious diseases, including severe acute respiratory syndrome. [ABSTRACT FROM AUTHOR]