An alternative method for estimation of annual extreme wind speeds

Yi Hui,Qingshan Yang,Zhengnong Li 한국풍공학회 2014 Wind and Structures, An International Journal (WAS Vol.19 No.2

This paper presents a method of estimation of extreme wind. Assuming the extreme wind follows the Gumbel distribution, it is modeled through fitting an exponential function to the numbers of storms over different thresholds. The comparison between the estimated results with the Improved Method of Independent Storms (IMIS) shows that the proposed method gives reliable estimation of extreme wind. The proposed method also shows its advantage on the insensitiveness of estimated results to the precision of the data. The volume of extreme storms used in the estimation leads to more than 5% differences in the estimated wind speed with 50-year return period. The annual rate of independent storms is not a significant factor to the estimation.

Non-stationary and non-Gaussian characteristics of wind speeds

Yi Hui,Bo Li,Hiromasa Kawai,Qingshan Yang 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

Non-stationarity and non-Gaussian property are two of the most important characteristics of wind. These two features are studied in this study based on wind speed records measured at different heights from a 325 m high meteorological tower during the synoptic wind storms. By using the time-frequency analysis tools, it is found that after removing the low frequency trend of the longitudinal wind, the retained fluctuating wind speeds remain to be asymmetrically non-Gaussian distributed. Results show that such non-Gaussianity is due to the weak-stationarity of the detrended fluctuating wind speed. The low frequency components of the fluctuating wind speeds mainly contribute to the non-zero skewness, while distribution of the high frequency component is found to have high kurtosis values. By further studying the decomposed wind speed, the mechanisms of the non-Gaussian distribution are examined from the phase, turbulence energy point of view.

Building an Eco-city:university Dragon Boat Racing"s Effect and Self-development----Case Study of Jimei district in Xiamen, China

( Yihui Cheng ) 한국체육학회 2015 국제스포츠과학 학술대회 Vol.2015 No.1

Purpose: the effect of university sport has always been ignored by people, while in fact it really has a deep and wide effect to the area around the university. There are several famous universities in Jimei district, Xiamen, China, dragon boat racing has already become an important part of university sport in these universities, people not only students but also local people, tourists all attracted by the exciting chinese traditional sports game. This study has the objective to explore the effects that the university sport----university dragon boat racing provides to build the eco-city, analyze its social, economical, educational and cultural functions and find a good way for its own development in the process of building the eco-city. Method: The methods used in the study are field research, literature review and expert interview. The methods used here is to review the former research for finding the experience and to find the real function of university dragon boat racing for building the eco-city. Result: university dragon boat racing is not only a school game affecting the schools where it played, which is also a game affecting the area around the university. The effect includes social area, cultural environment, education and economical development. All these parts are the element of eco-environment, so the racing has great effect to eco-environment. Just because of these effects, the society made a good environment for the development of university dragon boat racing. For developing university dragon boat racing well, it should find a suitable way to match the city``s image and explore the culture value. university dragon boat racing is also a way for education, teaching the tradional culture. Conclusion: Firstly, the university dragon boat racing has great effect for building the eco-city, which has social function, educational function, cultural function and economical function. Secondly, to fulfill these function, university dragon boat racing should find its own way both for its self-development and affecting the environment.

Feasibility analysis of bone density evaluation with Hounsfield unit value after fibula flap reconstruction of jaw defect

Yihui Yang,Yifan Kang,Yifan Yang,Mengkun Ding,Xiaofeng Shan,Zhigang Cai 대한악안면성형재건외과학회 2023 Maxillofacial Plastic Reconstructive Surgery Vol.45 No.-

Background Implant-supported dentures have become an essential means of restoring occlusal function after jaw reconstruction. Bone mineral density (BMD) may influence the success rate of implant denture restorations. This study aimed to explore whether the Hounsfield unit (HU) value can be used to monitor the changing trend of fibular BMD after jaw reconstruction. Results A total of 54 patients who underwent maxillar/mandibular reconstruction with a fibula flap were included in this study. There was a significant correlation between the HU value and BMD at 1 week, 3 months, and 6 months after surgery, and both were significantly correlated with follow-up time. The difference between each pair of absorption rates (DAR) was less than 10% in 66.7% and 75.9% of patients at 3 and 6 months; however, the DAR was more than 20% in 12% and 13.8% of patients at 3 and 6 months, respectively. Conclusions There is a significant correlation between HU value and BMD. The HU value can be used to roughly reflect the fibular BMD changing trend in a group of patients as opposed to an individual, and the HU value is not equivalent to BMD. Trial registration ChiCTR, ChiCTR2300069661, retrospectively registered on 22 March 2023. Retrospectively registered, https:// www. chictr. org. cn/ showp roj. html? proj= 188953.

Separating paint mist from paint spraying waste gas: mechanism, model and application

Yihui Zhou,Xi He,Wang Li,Tao Xu,Dong Xie,Xin Dai,Zhang Liu,Hanqing Wang,Gang Yu 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.5

The paint spraying waste gas contains a large amount of paint mist, volatile organic compounds (VOCs) and other hazardous materials, which seriously affects human health and atmospheric environment. Paint mist cannot be separated from paint spraying waste gas effectively by the existing dry filtration methods because of the filter blocking. A new separation process and a novel coupling device with high separation efficiency have been developed. A numerical model was established to optimize the structure and operation parameters of the baffle interceptor by hydrodynamics method which verified by the coupling device experiment. From the simulating results, when plate spacing was 20 ㎜, folding angle was 90° and airflow velocity was up to 8 ㎧, the separation efficiency of paint mist with the diameter of 15 ㎛ was 84.7% and the pressure drop of the baffle interceptor was 220.2 ㎩. Experiment was conducted under the above-optimized conditions, and the results showed that the pressure drop of the baffle interceptor was 303.33 ㎩, and the paint mist separation efficiencies of the baffle interceptor and the interception-filtration coupling device were 78.34% and 96.38%, respectively.

Research on Grid Side Power Factor of Unity Compensation Method for Matrix Converters

Yihui Xia,Xiaofeng Zhang,Zhihao Ye,Mingzhong Qiao 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

Input filters are very important to matrix converters (MCs). They are used to improve grid side current waveform quality and to reduce the input voltage distortion supplied to the grid side. Due to the effects of the input filter and the output power, the grid side power factor (PF) is not at unity when the input power factor angle is zero. In this paper, the displacement angle between the grid side phase current and the phase voltage affected by the input filter parameters and output power is analyzed. Based on this, a new grid side PF unity compensation method implemented in the indirect space vector pulse width modulation (ISVPWM) method is presented, which has a larger compensation angle than the traditional compensation method, showing a higher grid side PF at unity in a wide output power range. Simulation and experimental results verify that the analysis of the displacement angle between the grid side phase current and the phase voltage affected by the input filter and output power is right and that the proposed compensation method has a better grid side PF at unity.

Burkholderia thailandensis outer membrane vesicles exert antimicrobial activity against drug-resistant and competitor microbial species

Yihui Wang,Joseph P. Hoffmann,Chau-Wen Chou,Kerstin Höner zu Bentrup,Joseph A. Fuselier,Jacob P. Bitoun,William C. Wimley,Lisa A. Morici 한국미생물학회 2020 The journal of microbiology Vol.58 No.7

Gram-negative bacteria secrete outer membrane vesicles (OMVs) that play critical roles in intraspecies, interspecies, and bacteria-environment interactions. Some OMVs, such as those produced by Pseudomonas aeruginosa, have previously been shown to possess antimicrobial activity against competitor species. In the current study, we demonstrate that OMVs from Burkholderia thailandensis inhibit the growth of drug-sensitive and drug-resistant bacteria and fungi. We show that a number of antimicrobial compounds, including peptidoglycan hydrolases, 4-hydroxy-3-methyl-2-(2-nonenyl)- quinoline (HMNQ) and long-chain rhamnolipid are present in or tightly associate with B. thailandensis OMVs. Furthermore, we demonstrate that HMNQ and rhamnolipid possess antimicrobial and antibiofilm properties against methicillin- resistant Staphylococcus aureus (MRSA). These findings indicate that B. thailandensis secretes antimicrobial OMVs that may impart a survival advantage by eliminating competition. In addition, bacterial OMVs may represent an untapped resource of novel therapeutics effective against biofilm- forming and multidrug-resistant organisms.

Properties of alkali-solubilized collagen solution crosslinked by N-hydroxysuccinimide activated adipic acid

Yihui Chen,Min Zhang,Wentao Liu,Guoying Li 한국유변학회 2011 Korea-Australia rheology journal Vol.23 No.1

The effect of N-hydroxysuccinimide activated adipic acid (NHS-AA) on the properties of alkali-solubilized collagen solutions was examined. The residual amino group content in crosslinked collagen, determined by trinitrobenzensulfonic acid (TNBS) assay, was decreased with increasing NHS-AA concentration. The results from differential scanning calorimeter (DSC) indicated that the maximum denaturation temperature (Td) of crosslinked collagen solution was about 4.2oC higher than that of un-crosslinked collagen solution (36.6℃). Moreover, the values of storage modulus (G'), loss modulus (G") and complex viscosity (η^*), obtained by means of dynamic frequency sweeps, were increased as NHS-AA concentration added up to 1.5mM, and then decreased slightly when further increased NHS-AA concentration. Besides, for collagen solution crosslinked with 1.5mM NHS-AA, dynamic denaturation temperature (T_(dd)) was about 1.1℃ lower than T_d (40.8℃), and the Arrhenius-type time-temperature superposition (TTS) principle was applied to yield the activation energy to be 474.4kJmol^(-1).

Research on Grid Side Power Factor of Unity Compensation Method for Matrix Converters

Xia, Yihui,Zhang, Xiaofeng,Ye, Zhihao,Qiao, Mingzhong The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

Input filters are very important to matrix converters (MCs). They are used to improve grid side current waveform quality and to reduce the input voltage distortion supplied to the grid side. Due to the effects of the input filter and the output power, the grid side power factor (PF) is not at unity when the input power factor angle is zero. In this paper, the displacement angle between the grid side phase current and the phase voltage affected by the input filter parameters and output power is analyzed. Based on this, a new grid side PF unity compensation method implemented in the indirect space vector pulse width modulation (ISVPWM) method is presented, which has a larger compensation angle than the traditional compensation method, showing a higher grid side PF at unity in a wide output power range. Simulation and experimental results verify that the analysis of the displacement angle between the grid side phase current and the phase voltage affected by the input filter and output power is right and that the proposed compensation method has a better grid side PF at unity.

Properties of alkali-solubilized collagen solution crosslinked by N-hydroxysuccinimide activated adipic acid

Chen, Yihui,Zhang, Min,Liu, Wentao,Li, Guoying 한국유변학회 2011 Korea-Australia rheology journal Vol.23 No.1

The effect of N-hydroxysuccinimide activated adipic acid (NHS-AA) on the properties of alkali-solubilized collagen solutions was examined. The residual amino group content in crosslinked collagen, determined by trinitrobenzensulfonic acid (TNBS) assay, was decreased with increasing NHS-AA concentration. The results from differential scanning calorimeter (DSC) indicated that the maximum denaturation temperature ($T_d$) of crosslinked collagen solution was about $4.2^{\circ}C$ higher than that of un-crosslinked collagen solution ($36.6^{\circ}C$). Moreover, the values of storage modulus (G'), loss modulus (G") and complex viscosity (${\eta}^*$), obtained by means of dynamic frequency sweeps, were increased as NHS-AA concentration added up to 1.5 mM, and then decreased slightly when further increased NHS-AA concentration. Besides, for collagen solution crosslinked with 1.5 mM NHS-AA, dynamic denaturation temperature ($T_{dd}$) was about $1.1^{\circ}C$ lower than $T_d$ ($40.8^{\circ}C$), and the Arrhenius-type time-temperature superposition (TTS) principle was applied to yield the activation energy to be $474.4kJmol^{-1}$.