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Acta Mechanica Sinica 2014年第4期30卷 607-614页

作者： Yang Liu Dong-Wei Shu school of Mechanical and Aerospace Engineering Nanyang Technological University

Delaminations in structures may significantly reduce the stiffness and strength of the structures and may affect their vibration characteristics. As structural components, beams have been used for various purposes, in many of which beams are often subjected to axial loads and static end moments. In the present study, an analytical solution is developed to study the coupled bending-torsion vibration of a homogeneous beam with a single delamination subjected to axial loads and static end moments. Euler-Bernoulli beam theory and the ＂free mode＂ assumption in delamination vibration are adopted. This is the first study of the influences of static end moments upon the effects of delaminations on natural frequencies, critical buckling loads and critical moments for lateral instability. The results show that the effects of delamination on reducing natural frequencies, critical buckling load and critical moment for lateral instability are aggravated by the presence of static end moment. In turn, the effects of static end moments on vibration and instability characteristics are affected by the presence of delamination. The analytical results of this study can serve as a benchmark for finite element method and other numerical solutions.

关键词： Vibration · Delamination ·End moments · Nat-ural frequency · Critical moment for lateral instability

Impact of undissociated volatile fatty acids on acidogenesis in a two-phase anaerobic system

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Journal of Environmental Sciences 2016年第4期28卷 196-201页

作者： Keke Xiao Yan Zhou Chenghong Guo Yogananda Maspolim Wun Jern Ng Advanced Environmental Biotechnology Centre Nanyang Environment and Water Research InstituteNanyang Technological University school of Civil and Environmental Engineering Nanyang Technological University

This study investigated the degradation and production of volatile fatty acids（VFAs）in the acidogenic phase reactor of a two-phase anaerobic system.20 mmol/L bromoethanesulfonic acid（BESA）was used to inhibit acidogenic methanogens（which were present in the acidogenic phase reactor）from degrading *** impact of undissociated volatile fatty acids（un VFAs）on＂net＂VFAs production in the acidogenic phase reactor was then evaluated,with the exclusion of concurrent VFAs degradation.＂Net＂VFAs production from glucose degradation was partially inhibited at high un VFAs concentrations,with 59%,37% and 60% reduction in production rates at 2190 mg chemical oxygen demand（COD）/L undissociated acetic acid（un HAc）,2130 mg COD/L undissociated propionic acid（un HPr）and 2280 mg COD/L undissociated n-butyric acid（un HBu）,*** profile of VFAs produced further indicated that while an un VFA can primarily affect its own formation,there were also un VFAs that affected the formation of other VFAs.

关键词： Anaerobic process Waste treatment Substrate inhibition Undissociated volatile fatty acids Acidogenesis

Analysis of the Mobile Communications Market Shares in China Based on Improved Stackelberg Model

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China Communications 2008年第3期5卷 119-124页

作者： Sunanda Sangwan nanyang Business school Nanyang Technological University

Based on improved Cournot model and Stackelberg model,this paper analyzes the firstmover advantage of China Mobile which is in a dominant position;then,by using complete information dynamic game,this paper analyzes the market shares of the oligarchic monopoly market of the mobile communications industry before the restructuring of the telecom industry and tests the analysis conclusion;at the same time,this paper analyzes the market shares in initial stage and mature stage of the mobile communications market after the *** to the analysis of this paper,China Mobile's market share will drop after the restructuring,the restructuring has a certain effect,but China Mobile is still in a leading *** the duopoly market before the restructuring or the three oligopoly market after the restructuring,every mobile operator has a relatively fixed market share under stable *** shows that mobile operators in China should cooperate on the basis of competition when developing the domestic market,and explore the international market to achieve greater development.

关键词： mobile communications market shares game analysis

＂The Tastes of Asia＂： Leung Ping-kwan, Foodscape, and the Politics of Representation

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Frontiers of Literary Studies in China-Selected Publications from Chinese Universities 2017年第4期11卷 739-775页

作者： Songjian ZHANG school of humanities Nanyang Technological University 50 Nanyang Ave 639798Singapore

Leung Ping-kwan （1949-2o13）, a leading writer and cultural critic of Hong Kong, has around ten collections of poems published over the past few decades. Beginning in 1997, Leung wrote about food, making significant contributions to poetry in Chinese. Drawing literary texts from Leung＇s collections of poetry, this paper aims to cast light on the role that Leung has played in the shaping of foodscape poetics and how he elaborates and addresses historical memory and cultural politics. In addition, this paper contends that his deconstruction of nationalism and an emphasis on ＂wisdom of peoples＇ livlihood＂ lies at the core of Leung＇s foodscape poetics, and they constitute a ＂positionality＂ rooted in his experience in Hong Kong.

关键词： Leung Ping-kwan foodscape diaspora cultural identity

Laterally pre-compressed SiC tiles against long rod impact

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Defence Technology（防务技术） 2018年第5期14卷 585-589页

作者： Bo-yang Luo Wei-liang Goh Zhong Chen Jian-ming Yuan Temasek Laboratories Nanyang Technological University school of Materials Science and Engineering Nanyang Technological University

A combined experimental and computational study was carried out to investigate ballistic performance of laterally preload compressed SiC tile against long rod impact. A 100 x 100 by 20 mm thick SiC tile was pushed into a 5 mm thick steel frame at high temperature of 430 ℃ so that after cool down to room temperature, the lateral preload compressive stress was developed in the SiC tiles. Depth of penetration tests of the SiC tiles with and without pre-stress were performed, where tungsten alloy long rods at a nominal velocity of 1240 m/s were launched to hit the SiC tiles backed by the steel blocks. Compared with the SiC tiles without any pre-stress, the pre-compressed SiC tiles were found to reduce significantly the residual penetration in the backing block. Simulations were carried out using the LS-dyna hydrocode,taking account of preload stress. The simulations showed that the lateral preload compression strengthened the intact SiC tiles and dwell occurred in the early penetration stage, eroding the striking long rod efficiently.

关键词： Pre-compressed SiC tile DOP test WHA long rod

Effect of a high strength chemical industry wastewater on microbial community dynamics and mesophilic methane generation

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Journal of Environmental Sciences 2014年第4期26卷 875-884页

作者： Harish Venkatakrishnan Youming Tan Maszenan bin Abdul Majid Santosh Pathak Antonius Yudi Sendjaja Dongzhe Li Jerry Jian Lin Liu Yan Zhou Wun Jern Ng school of Civil and Environmental Engineering Nanyang Technological University Advanced Environmental Biotechnology Center Nanyang Environment and Water Research Institute Nanyang Technological University school of Public Health Shanghai Jiaotong University nanyang Environment and Water Research Institute Nanyang Technological University Sembcorp Industries Ltd.

A high strength chemical industry wastewater was assessed for its impact on anaerobic microbial com- munity dynamics and consequently mesophilic methane generation. Cumulative methane production was 251 mL/g total chemical oxygen demand removed at standard temperature and pressure at the end of 30 days experimental period with a highest recorded methane percentage of 80.6% of total biogas volume. Volatile fatty acids （VFAs） analysis revealed that acetic acid was the major intermediate VFAs produced with propionic acid accumulating over the experimental period. Quantitative analysis of microbial communities in the test and control groups with quantitative real time polymerase chain reaction highlighted that in the test group, Eubacteria （96.3%） was dominant in comparison with methanogens （3.7%）. The latter were dominated by Methanomicrobiales and Methanobacteriales while in test groups increased over the experimental period, reaching a maximum on day 30. Denaturing gradient gel electrophoresis profile was performed, targeting the 16S rRNA gene of Eubacteria and Archaea, with the DNA samples extracted at 3 different time points from the test groups. A phylogenetic tree was constructed for the sequences using the neighborhood joining method. The analysis revealed that the presence of organisms resembling Syntrophomonadaceae could have contributed to increased production of acetic and propionic acid intermediates while decrease of organisms resembling Pelotomaculum sp. could have most likely contributed to accumulation of propionic acid. This study suggested that the degradation of organic components within the high strength industrial wastewater is closely linked with the activity of certain niche microbial communities within eubacteria and methanogens.

关键词： biochemical methane potential biogas community dynamics denaturing gradient gel electrophoresis industrial chemical wastewater quantitative real-time PCR

Historical Imagination and Cultural Identity: Revisiting Yang Mu's Poetics of History

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Frontiers of Literary Studies in China-Selected Publications from Chinese Universities 2019年第1期13卷 49-71页

作者： Songjian ZHANG school of humanities Nanyang Technological UniversitySingapore 637332Singapore

This essay aims to examine one key dimension of Yang Mu's literary writings, namely, his "poetics of history." From 1968 to 2011, Yang Mu created approximately twenty-two poems on history at different stages of his Iife. This paper holds that, by invoking historical memory, Yang Mu not only offers his critical response to the polemics on modern Chinese poetry in 1970s Taiwan but also brilliantly conceives of two specific approaches and modes, namely,"observing and presenting history" and "reenacting and re-interpreting history." This paper argues that the second approach and mode, e.g., Yang Mu speaking through fictionalized and dramatized historical figures, should be viewed as Yang's insight, as it powerfully displays the originality and depth of the poet's vision. In addition, as the focus of Yang Mu's historical imagination shifts from Chinese mainland to Taiwan over the decades, his cultural identity undergoes a major transforma廿on;in a sense, this shift results from the rise of Taiwan's nativization movement in the age of globalization.

关键词： Yang Mu poetry history cultural identity

Adaptive failure compensation for uncertain systems with multiple inputs

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Journal of Systems Engineering and Electronics 2011年第1期22卷 70-76页

作者： Wei Wang Changyun Wen school of Electrical and Electronic Engineering Nanyang Technological University Nanyang Avenue 639798 Singapore

The aim of this paper is to develop controllers for uncertain systems in the presence of stuck type actuator failures.A new scheme is proposed to design output feedback controllers for a class of uncertain systems having redundant control inputs,with which the relative degrees of transfer functions are *** deal with these inputs using backstepping technique,a pre-filter is introduced before each actuator such that its output is the input to the *** orders of the pre-filters are chosen properly to ensure all their inputs can be designed at the same step in the systematic *** compensate for the effects of possible failed actuators,more uncertain parameters than system parameters are required to be *** the proposed scheme,the global boundedness of the closed-loop system can still be ensured and the system output can be regulated to a specific value when some of the actuators＇ outputs are stuck at unknown fixed values.

关键词： adaptive control actuator failure failure compensation pre-filter backstepping.

Self-powered pressure sensor for ultra-wide range pressure detection

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Nano Research 2017年第10期10卷 3557-3570页

作者： Kaushik Parida Venkateswarlu Bhavanasi Vipin Kumar Ramaraju Bendi Pooi See Lee school of Materials Science and Engineering Nanyang Technological University Nanyang Avenue 639798 Singapore

The next generation of sensors should be self-powered, maintenance-free, precise, and have wide-ranging sensing abilities. Despite extensive research and development in the field of pressure sensors, the sensitivity of most pressure sensors declines significantly at higher pressures, such that they are not able to detect a wide range of pressures with a uniformly high sensitivity. In this work, we demonstrate a single-electrode triboelectric pressure sensor, which can detect a wide range of pressures from 0.05 to 600 kPa with a high degree of sensitivity across the entire range by utilizing the synergistic effects of the piezoelectric polarization and triboelectric surface charges of self-polarized polyvinyldifluoride-trifluoroethylene （P（VDF-TrFE）） sponge. Taking into account both this wide pressure range and the sensitivity, this device exhibits the best performance relative to that of previously reported self-powered pressure sensors. This achievement facilitates wide-range pressure detection for a broad spectrum of applications, ranging from simple human touch, sensor networks, smart robotics, and sports applications, thus paving the way forward for the realization of next-generation sensing devices. Moreover, this work addresses the critical issue of saturation pressure in triboelectric nanogenerators and provides insights into the role of the surface charge on a piezoelectric polymer when used in a triboelectric nanogenerator.

关键词： self-powered triboelectric piezoelectric nanogenerator pressure sensor

On Feasible Region of Droop-based Fast Frequency Response Controller Parameters of Wind Turbines

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1690-1695页

作者： Junkai Huang Yan Xu school of Electrical and Electronic Engineering Nanyang Technological University50 Nanyang AvenueSingapore

Droop-based fast frequency response(FFR)control of wind turbines can improve the frequency performance of power systems with high penetration of wind *** formulating the feasible region of the droop-based FFR controller parameters can allow system operators to conveniently assess the feasibility of FFR controller parameter settings to comply with system frequency security,and efficiently tune and optimize FFR controller parameters to meet frequency security ***,the feasible region of FFR controller parameters is inherently nonlinear and implicit because the power point tracking controllers of wind turbine would counteract the effect of FFR *** address this issue,this letter proposes a linear feasible region formulation method,where frequency regulation characteristics of wind turbines,the dead band,and reserve limits of generators are all *** effectiveness of the proposed method and its application is demonstrated on a 10-machine power system.

关键词： Wind turbine fast frequency response feasible region frequency security