Molecular dynamics study on mechanical properties of C-S-H composites

Xianfeng Wang,Peng Wei,Rui Han,Wei Xie,Taoran Li,Dawang Li,Yonggang Peng,Zhen Chen,Feng Xing 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.S1

In this paper, the mechanical properties of calcium silicate hydrate gel (C-S-H) are investigated with molecular dynamics (MD)simulations, in which the Tobermorite 9Å, Tobermorite 11Å, Tobermorite 14Å and Jennite crystals are treated as fundamentalmodels of the C-S-H nanostructure. The initial structures of the crystal models are firstly preprocessed and optimized, andthen are simulated in the canonical (NVT) ensemble conditions. The orthotropic elastic constants of the C-S-H nanostructureare determined and used to derive the bulk and shear moduli via the Voigt-Reuss-Hill method. The self-consistent, Mori-Tanaka, and Voigt methods are employed to compute the mechanical properties of various mixtures of C-S-H composites withdifferent porosities. The simulated results are found to be in a reasonable agreement with those obtained from nanoindentationtests, while the result obtained from the Mori-Tanaka method appears to be the closest to the experimental one. It could also be observed that the mechanical properties of C-S-H vary within a certain range as the porosity and proportionsof the components change.

Early age behavior analysis for reinforced concrete bridge pier

Xianfeng Wang,Dawang Li,Ningxu Han,Feng Xing 사단법인 한국계산역학회 2016 Computers and Concrete, An International Journal Vol.18 No.5

In this study, the construction of a reinforced concrete bridge pier was analyzed from durability point of view. The goal of the study is to analyze the crack iniation condition due to construction and present some recommendations for construction conditions of the reinforced concrete bridge pier. The bridge is located at the western port area of Shenzhen, where the climate is high temperature and humidity. To control the cracking of concrete, a construction simulation was carried out for a heat transfer problem as well as a thermal stress problem. A shrinkage model for heat produced due to cement hydration and a Burger constitutive model to simulate the creep effect are used. The modelling based on Femmasse© is verified by comparing with the testing results of a real underground abutment. For the bridge pier, the temperature and stress distribution, as well as their evolution with time are shown. To simulate the construction condition, four initial concrete temperatures (5°C, 10°C, 15°C, 20°C) and three demoulding time tips (48h, 72h, 96h) are investigated. From the results, it is concluded that a high initial concrete temperature could result in a high extreme internal temperature, which causes the early peak temperature and the larger principle stresses. The demoulding time seems to be less important for the chosen study cases. Currently used 72 hours in the construction practice may be a reasonable choice.

Effect of lead sulfate on chloride ion transport properties in cementitious material

Xianfeng Wang,Yabin Yuan,Yingxin Huang,Tielin Han,Weilun Wang,Jian Liu,Feng Xing 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.S1

A novel microcapsule-based self-healing system was developed in Guangdong Key Laboratory of Durability in Coastal CivilEngineering to prolong the concrete service life, in which lead sulfate is used as the shell material of the microcapsules. Theself-healing system is triggered by the reaction of lead sulfate with chloride ion. In this study, the effect of lead sulfate onchloride ion transport in cement-based materials was investigated. The bulk diffusion and rapid chloride migration tests werecarried out. The time dependence of chloride diffusion was analysed based on the results of the Bulk diffusion test. The changein the microstructure of cement-based materials upon incorporation of lead sulfate was observed and analysed via mercuryintrusion porosimetry and scanning electron microscopy. Results showed that chloride-binding was prevalent at an immersionperiod of less than 90 days, while sulfate attack superseded after 90 days. Therefore, the impact of both factors needs to beconsidered when utilizing lead sulfate as a shell material in cementitious materials.

과제 유형에 따른 중국인 한국어 학습자의 관형사형 어미 중간언어 변이 연구

왕현풍 ( Xianfeng Wang ) 사단법인 아시아문화학술원 2021 인문사회 21 Vol.12 No.3

이 연구에서는 중국인 학습자를 대상으로 과제 유형과 숙달도에 따른 관형사형 어미의 중간언어 변이 양상이 어떻게 나타나는지 살펴보고자 하였다. 이를 위하여 중국인 중급 학습자 40명, 고급 학습자 40명을 대상으로 문법 판단 테스트, 번역 과제, 구어 인터뷰로 진행하였다. 이 연구 결과, 과제 유형에 따라 관형사형 어미 사용에 변이가 나타났으며, 숙달도에 따라서도 그의 정확도와 변이 양상까지 달라지는 사실을 확인할 수 있었다. 나아가 문어·구어 과제를 바탕으로 중국인 학습자들의 관형사형 어미에 대한 습득과 산출 과정을 살펴본 결과, 중간언어 변이가 언어적 맥락에서 많이 나타났음을 확인할 수 있었다. 또한 학습자의 숙달도가 높을수록 중간언어 변이 양상이 목표어인 한국어에 더 가까워지는 것도 살펴볼 수 있었다. 이 연구 결과가 한국어 학습자들의 중간언어 체계 구축을 위한 기초자료로 제공될 수 있기를 기대한다. This study was aim to examine Chinese Korean learners how the Interlanguage variation of Adnominal Ending Form according to task type and proficiency. To this end, grammar judgement tests, translation tasks, and oral interviews were conducted on 40 intermediate learners and 40 advanced learners. It was confirmed that variation occurred in the use of Adnominal Ending Form was controlled by task type, and that its accuracy and variation varied depending on mastery. Furthermore, Based on the written and spoken language tasks, Chinese learners’ acquisition and calculation of Adnominal Ending Form confirmed that there were many Interlanguage variations in the linguistic context. In addition, The higher the learner’s proficiency, the closer the Interlanguage variation becomes to the target Korean language. These results are expected to be provided as basic data for the establishment of an Interlanguage system for Korean learners.

Involvement of JNK-initiated p53 accumulation and phosphorylation of p53 in pseudolaric acid B induced cell death

Xianfeng Gong,Minwei Wang,Shin-ichi Tashiro,Satoshi Onodera,Takashi Ikejima 생화학분자생물학회 2006 Experimental and molecular medicine Vol.38 No.4

A terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay was used to determine that apoptosis causes HeLa cell death induced by pseudolaric acid B. The c-Jun N-terminal kinase (JNK) inhibitor SP600125 decreased p53 protein expression during exposure to pseudolaric acid B. SP600125 decreased the phosphorylation of p53 during pseudolaric acid B exposure, indicating that JNK mediates phosphorylation of p53 during the response to pseudolaric acid B. SP600125 reversed pseudolaric acid B-induced down-regulation of phosphorylated extracellular signal-regulated pro-tein kinase (ERK), and protein kinase C (PKC) was activated by pseudolaric acid B, whereas stau-rosporine, calphostin C, and H7 partly blocked this effect. These results indicate that p53 is partially regulated by JNK in pseudolaric acid B-induced HeLa cell death and that PKC participates in pseudolaric acid B-induced HeLa cell death.

Pseudolaric acid B induces apoptosis via activation of c-Jun N-terminal kinase and caspase-3 in HeLa cells

Xianfeng Gong,M inwei Wang,Zhen Wu,S hin -ichi T ashiro,Satoshi Onodera,Takashi Ikejima 생화학분자생물학회 2004 Experimental and molecular medicine Vol.36 No.6

Pseudolaric acid B was isolated from Pseudolarix kaempferi Gordon (Pinaceae) and was evaluated for the anti-cancer effect in HeLa cells. We ob-served that pseudolaric acid B inhibited cel proliferation and induced apoptosis in a time- and dose-dependent manner. HeLa cels treated with pseudolaric acid B showed typical characteristics of apoptosis including the morphological changes and DNA fragmentation. JNK inhibitor, SP60125, markedly inhibited pseudolaric acid B-induced cel death. In addition, Bcl-2 expression was down-re-gulated while Bax protein level was up-regulated. Caspase-3 inhibitor, z-DEVD-fmk, partially blocked pseudolaric acid B-induced cel death, and the expression of two classical caspase substrates, PARP and ICAD, were both decreased in a time- pase activation.

Traffic speed mapping with cellular network signaling data by FOSS4G

Wang Weifeng,Zhu Kemin,Liu Junli,Hu Jinghao,Raganvan Venkatesh,Xu Jiang,Song Xianfeng 대한공간정보학회 2022 Spatial Information Research Vol.30 No.2

Mapping traffic speed on road networks is crucial for urban traffic management and the development of intelligent transportation systems. Traditionally, information regarding traffic speed can be obtained from locationfixed sensors, such as loop detectors and cameras; however, these methods are limited to major road crosses. Recently, a considerable attention has been paid to utilizing vehicles with mobile phones as probes for collecting traffic information. This study proposes an open-source GIS approach to map traffic speeds in a road network. First, public service vehicles (PSVs) were identified from cellular network signaling data by measuring the similarity between cell-ID trajectories and bus routes. Then, the cell-ID trajectories of PSVs were refined into high-quality spatiotemporal trajectories, and projected onto the road network via heuristic global optimization. Finally, hourly traffic speed maps were computed by weighing the speeds of the PSVs in the road network. The approach was implemented using free and open source software for geospatial mapping stacks of toolkits (Python, TimescaleDB/PostGIS, Pandas/Pygmo2, and Matplotlib/Seaborn); this application demonstrated good results using cellular network signaling data and GPS trajectories collected in Huilongguan district, Beijing, China. Moreover, this demonstration illustrates that probe mobile monitoring is emerging as a critical technology for traffic monitoring supplements, which can help develop a comprehensive view of the roads and reduce the cost of monitoring a large area.

Reducing higher alcohols by nitrogen compensation during fermentation of Chinese rice wine

Xianfeng Zhong,Ali Wang,Yubo Zhang,Ziying Wu,Bin Li,Hua Lou,Guidong Huang,Haixiang Wen 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.6

Excessive amount of higher alcohols in alcoholicbeverages causes unwell and side-effect for consumersalthough adequate consumption offers joy and pleasure. Therefore, reducing higher alcohols in alcoholic beveragesis necessary. We used nitrogen compensation to reducehigher alcohols with Chinese rice wine as an experimentalmodel. Higher alcohols including isobutyl alcohols, isoamylalcohols, and b-phenethyl alcohols were significantlydecreased by 19.27, 23.03 and 19.43%, respectively, when200 mg/L (NH4)2HPO4, 5% (w/v) yeast, and 11% wheatKoji were added to fermentation broth. Meanwhile,important quality parameters remained unchanged includingfree amino acids, organic acids, biogenic amines, andesters. The expression of glutamate dehydrogenase 1 gene(GDH1) and glutamine synthetase gene (GLN1) was significantlyenhanced, 26.9- and 1.9-folds respectively. Theseresults suggest that ammonium compensation could effectivelydecrease higher alcohols in Chinese rice wine byactivating glutamate dehydrogenase (GDH) pathway inammonium assimilation.

Traffic speed mapping with cellular network signaling data by FOSS4G

Wang Weifeng,Zhu Kemin,Liu Junli,Hu Jinghao,Raganvan Venkatesh,Xu Jiang,Song Xianfeng 대한공간정보학회 2022 Spatial Information Research Vol.30 No.1

Mapping traffic speed on road networks is crucial for urban traffic management and the development of intelligent transportation systems. Traditionally, information regarding traffic speed can be obtained from locationfixed sensors, such as loop detectors and cameras; however, these methods are limited to major road crosses. Recently, a considerable attention has been paid to utilizing vehicles with mobile phones as probes for collecting traffic information. This study proposes an open-source GIS approach to map traffic speeds in a road network. First, public service vehicles (PSVs) were identified from cellular network signaling data by measuring the similarity between cell-ID trajectories and bus routes. Then, the cell-ID trajectories of PSVs were refined into high-quality spatiotemporal trajectories, and projected onto the road network via heuristic global optimization. Finally, hourly traffic speed maps were computed by weighing the speeds of the PSVs in the road network. The approach was implemented using free and open source software for geospatial mapping stacks of toolkits (Python, TimescaleDB/PostGIS, Pandas/Pygmo2, and Matplotlib/Seaborn); this application demonstrated good results using cellular network signaling data and GPS trajectories collected in Huilongguan district, Beijing, China. Moreover, this demonstration illustrates that probe mobile monitoring is emerging as a critical technology for traffic monitoring supplements, which can help develop a comprehensive view of the roads and reduce the cost of monitoring a large area.

Tuning the Optical Orbital Angular Momentum of a Focused Gaussian Beam in an Optical Supperlattice under the Electro-optic Effect

Jie Wang,Jianhong Shi,Linghao Tian,Xianfeng Chen 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.8

In this paper, we theoretically propose a new method to generate and tune the optical orbital angular momentum. A focused Gaussian beam passing through an optical superlattice under the electro-optic effect carries orbital angular momentum (OAM). This kind of OAM arises from the curl of the polarization. By adjusting the external electric field, the beam waist radius and the crystal length, we can obtain a dramatic variation of the OAM across the output light transverse section. This invention will find applications in the area of optical manipulation.