Influence of particle packing on fracture properties of concrete

Huan He,Piet Stroeven,Martijn Stroeven,Lambertus Johannes Sluys 사단법인 한국계산역학회 2011 Computers and Concrete, An International Journal Vol.8 No.6

Particle packing on meso-level has a significant influence on workability of fresh concrete and also on the mechanical and durability properties of the matured material. It was demonstrated earlier that shape exerts but a marginal influence on the elastic properties of concrete provided being packed to the same density, which is not necessarily the case with different types of aggregate. Hence, elastic properties of concrete can be treated as approximately structure-insensitive parameters. However, fracture behaviour can be expected structure-sensitive. This is supported by the present study based on discrete element method (DEM) simulated three-phase concrete, namely aggregate, matrix and interfacial transition zones (ITZs). Fracture properties are assessed with the aid of a finite element method (FEM) based on the damage materials model. Effects on tensile strength due to grain shape and packing density are investigated. Shape differences are shown to have only modest influence. Significant effects are exerted by packing density and physicalmechanical properties of the phases, whereby the ITZ takes up a major position.

Optimization of particle packing by analytical and computer simulation approaches

Huan He,Piet Stroeven,Martijn Stroeven,Lambertus Johannes Sluys 사단법인 한국계산역학회 2012 Computers and Concrete, An International Journal Vol.9 No.2

Optimum packing of aggregate is an important aspect of mixture design, since porosity may be reduced and strength improved. It may also cause a reduction in paste content and is thus of economic relevance too. Several mathematic packing models have been developed in the literature for optimization of mixture design. However in this study, numerical simulation will be used as the main tool for this purpose. A basic, simple theoretical model is used for approximate assessment of mixture optimization. Calculation and simulation will start from a bimodal mixture that is based on the mono-sized packing experiences. Tri-modal and multi-sized particle packing will then be discussed to find the optimum mixture. This study will demonstrate that computer simulation is a good alternative for mixture design and optimization when appropriate particle shapes are selected. Although primarily focusing on aggregate, optimization of blends of Portland cement and mineral admixtures could basically be approached in a similar way.

Primary damage of 10 keV Ga PKA in bulk GaN material under different temperatures

He Huan,He Chaohui,Zhang Jiahui,Liao Wenlong,Zang Hang,Li Yonghong,Liu Wenbo 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

Molecular dynamics (MD) simulations were conducted to investigate the temperature effects on the primary damage in gallium nitride (GaN) material. Five temperatures ranging from 300 K to 900 K were studied for 10 keV Ga primary knock-on atom (PKA) with inject direction of [0001]. The results of MD simulations showed that threshold displacement energy (Ed) was affected by temperatures and at higher temperature, it was larger. The evolutions of defects under various temperatures were similar. However, the higher temperature was found to increase the peak number, peak time, final time and recombination efficiency while decreasing the final number. With regard to clusters, isolated point defects and little clusters were common clusters and the fraction of point defects increased with temperature for vacancy clusters, whereas it did not appear in the interstitial clusters. Finally, at each temperature, the number of Ga interstitial atoms was larger than that of N and besides that, there were other different results of specific types of split interstitial atoms.

Wnt pathway is involved in 5-FU drug resistance of colorectal cancer cells

Lingfeng He,Hong Zhu,Shiying Zhou,Ting Wu,Huan Wu,Huan Yang,Huiwen Mao,Chandra SekharKathera,Avilala Janardhan,Ashlin M. Edick,Anna Zhang,Zhigang Hu,Feiyan Pan,Zhigang Guo 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. 5-Fluorouracil (5-FU) is widely used in the treatment of cancers, but its antineoplastic activity is limited in drug-resistant cancer cells. To investigate the detailed mechanism of 5-FU resistance, we developed a model of 5-FU-resistant cells from HCT-8 cells, a wellestablished colorectal cancer cell line. We found that the drug-resistant cells demonstrated high expression of TCF4 and β-catenin, indicating an upregulated Wnt pathway. A microarray analysis revealed that the suppression of the checkpoint kinase 1 (CHK1) pathway explained the resistance to 5-FU, especially in p53 wild-type cancer cells such as HCT-8. Our data also demonstrated that the CHK1 pathway is suppressed by the Wnt pathway in 5-FU-resistant cells. In summary, we have discovered a novel mechanism for 5-FU resistance mediated by histone deacetylation, which also revealed the crosstalk between the Wnt pathway and CHK1 pathway.

Parametric pitch instability investigation of Deep Draft Semi-submersible platform in irregular waves

Huan Mao,He-zhen Yang 대한조선학회 2016 International Journal of Naval Architecture and Oc Vol.8 No.1

Parametric pitch instability of a Deep Draft Semi-submersible platform (DDS) is investigated in irregular waves. Parametric pitch is a form of parametric instability, which occurs when parameters of a system vary with time and the variation satisfies a certain condition. In previous studies, analyzing of parametric instability is mainly limited to regular waves, whereas the realistic sea conditions are irregular waves. Besides, parametric instability also occurs in irregular waves in some experiments. This study predicts parametric pitch of a Deep Draft Semi-submersible platform in irregular waves. Heave motion of DDS is simulated by wave spectrum and response amplitude operator (RAO). Then Hill equation for DDS pitch motion in irregular waves is derived based on linear-wave theory. By using Bubnov-Galerkin approach to solve Hill equation, the corresponding stability chart is obtained. The differences between regular-waves stability chart and irregular-waves stability chart are compared. Then the sensitivity of wave parameters on DDS parametric pitch in irregular waves is discussed. Based on the discussion, some suggestions for the DDS design are proposed to avoid parametric pitch by choosing appropriate parameters. The results indicate that it's important and necessary to predict DDS parametric pitch in irregular waves during design process.

Breathing-based Continuous Non-intrusive User Verification Leveraging Commodity WiFi

Huan Dai,Jingjing Jiang,Jiaju Ma,He Huang,Hongbo Liu 한국통신학회 2022 Journal of communications and networks Vol.24 No.2

This paper opens up a new pathway of the utilityof breathing pattern for user verification. We demonstrate thatit is possible to capture people’s breathing pattern leveragingcommodity WiFi devices. While prior solutions for biometricsbaseduser recognition usually require dedicated devices (e.g.,video cameras or IR sensors), this paper introduces the firstgeneral, low-cost breathing-based user verification system usingcommodity WiFi devices. The proposed system is based onthe fact that the breathing pattern always keeps consistentfor the same user but distinct among different people. Ourinnovative method successfully extracts the breathing patternof different people based on channel state information of WiFisignal to facilitate user verification. The prototype study usingtwo commodity WiFi devices can differentiate people with anaverage verification accuracy over 90%, suggesting that ourbreathing-based user verification system using commerical offthe-shelf (COTS) WiFi is promising to be one of the most criticalmethods in biometrics.

Benefit of Post-mastectomy Radiotherapy of the Supra-/infraclavicular Lymphatic Drainage Area in Breast Cancer Patients

He, Zhen-Yu,Wu, San-Gang,Zhou, Juan,Sun, Jia-Yuan,Li, Feng-Yan,Lin, Qin,Guo, Ling,Lin, Huan-Xin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.14

Background: This study investigated the survival benefit of radiotherapy (RT) of the supra- and infraclavicular lymphatic drainage area in Chinese women with T1-2N1M0 breast cancer receiving mastectomy. Methods: A total of 593 cases were retrospectively reviewed from 1998 to 2007. The relationship between supra- or infraclavicular fossa relapse (SCFR) and post-operative RT at the supra-/infraclavicular lymphatic drainage area was evaluated. Results: The majority of patients (532/593; 89. 8%) received no RT while 61 patients received RT. The median follow-up was 85 months. Among patients without RT, 54 (10. 2%) developed recurrence in the chest wall or ipsilateral SCFR. However, none of the 61 patients who underwent RT demonstrated SCFR. One patient who received RT (1. 6%) experienced recurrence in the chest wall. Univariate analysis revealed that age and molecular subtype (both P < 0. 05) were two prognostic factors related to supraclavicular and infraclavicular fossa relapse-free survival (SFRFS). Multivariate analysis revealed that only Her-2 positive status (P = 0. 011) was an independent predictor of SFRFS. RT had no influence on distant metastasis (P = 0. 328) or overall survival (P = 0. 541). SCFR significantly affected probability of distant metastasis (P < 0. 001) and overall survival (P < 0. 001). Conclusion: Although RT was not significantly associated with SFRFS, postoperative RT was significantly associated with a lower locoregional (i. e., supraclavicular/infraclavicular and chest wall) recurrence rate. SCFR significantly influenced distant metastasis-free survival, which significantly influenced the overall survival of T1-2N1M0 breast cancer patients after mastectomy. Thus, prophylactic RT is recommended in T1-2N1M0 breast cancer patients, especially those who have Her-2 positive lesions.

Aerodynamic properties of a streamlined bridge-girder under the interference of trains

Huan Li,Xu-hui He,Liang Hu,Xiaojun Wei 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.35 No.3

Trains emerging on a streamlined bridge-girder may have salient interference effects on the aerodynamic properties of the bridge. The present paper aims at investigating these interferences by wind tunnel measurements, covering surface pressure distributions, near wake profiles, and flow visualizations. Experimental results show that the above interferences can be categorized into two primary effects, i.e., an additional angle of attack (AoA) and an enhancement in flow separation. The additional AoA effect is demonstrated by the upward-moved stagnation point of the oncoming flow, the up-shifted global symmetrical axis of flow around the bridge-girder, and the clockwise-deflected orientation of flow approaching the bridgegirder. Due to this additional AoA effect, the two critical AoAs, where flow around the bridge-girder transits from trailing-edge vortex shedding (TEVS) to impinging leading-edge vortices (ILEV) and from ILEV to leading-edge vortex shedding (LEVS) of the bridge-girder are increased by 4° with respect to the same bridge-girder without trains. On the other hand, the underlying flow physics of the enhancement in flow separation is the large-scale vortices shedding from trains instead of TEVS, ILEV, and LEVS governed the upper half bridge-girder without trains in different ranges of AoA. Because of this enhancement, the mean lift and moment force coefficients, all the three fluctuating force coefficients (drag, lift, and moment), and the aerodynamic spanwise correlation of the bridge-girder are more significant than those without trains.

CMTM5-v1, a four-transmembrane protein, presents a secreted form released via a vesicle-mediated secretory pathway

( He Nan Li ),( Xiao Huan Guo ),( Lu Ning Shao ),( Markus Plate ),( Xiao Ning Mo ),( Yu Wang ),( Wen Ling Han ) 한국생화학분자생물학회 (구 한국생화학회) 2010 BMB Reports Vol.43 No.3

The CKLF-like MARVEL transmembrane domain-containing family (CMTM) is a novel family of proteins linking classical chemokines and the transmembrane 4 superfamily (TM4SF). Our earlier studies indicated several CMTM members (such as CKLF1 and CMTM2) have a secreted form. This is the first report of the secreted form of CMTM5-v1, the major RNA splicing form of CMTM5, which is produced as small vesicles (<100 nm diameter) and floats at a peak density of 1.19 g/ml on continuous sucrose gradients. CMTM5-v1 has no obvious co-localization with CD63 or Golgi complex. In addition, brefeldin A but not wortmannin can inhibit the secretion of CMTM5-v1. Our results suggest that CMTM5-v1 might be secreted via a different vesicle-mediated secretory pathway, which will be helpful for the studies of vesicle-mediated secretion and MARVEL domain-containing proteins. [BMB reports 2010; 43(3): 182-187]

Iron-loaded Natural Clay as Heterogeneous Catalyst for Fenton-like Discoloration of Dyeing Wastewater

Huan-Yan Xu,Xiu-Lan He,Ze Wu,Lian-Wei Shan,Wei-Dong Zhang 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.10

The clay-based Fe-bearing catalyst was successfully prepared through ion-exchange reaction and applied as heterogeneous catalyst for discoloration of acid fuchsine (AF) in an aqueous solution by Fenton-like action.Experimental results demonstrated that the AF discoloration ratios increased by increasing Fe-loaded clay dosage and initial H2O2 concentration, and by decreasing the pH, respectively. The lower the initial AF concentration, the shorter the reaction time needed to achieve complete discoloration of AF. Comparative studies indicated that AF discoloration ratios were much higher in presence of Fe-loaded clay and H2O2 than those in presence of H2O2, raw natural clay or Fe-loaded clay only and raw natural clay and H2O2 jointly. After AF discoloration, there existed no new phases in the clay samples detected by XRD and no change in the clay crystal morphology observed by SEM. A mechanism proposed suggested adsorption and Fenton-like reaction were responsible for discoloration of AF.