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An hp-angular adaptivity with the discrete ordinates method for Boltzmann transport equation
Dai Ni,Zhang Bin,Wang Xinyu,Lu Daogang,Chen Yixue 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2
This paper describes an hp-angular adaptivity algorithm in the discrete ordinates method for Boltzmann transport applications with strong angular effects. This adaptivity uses discontinuous finite element quadrature sets with different degrees, which updates both angular mesh and the degree of the underlying discontinuous finite element basis functions, allowing different angular local refinement to be applied in space. The regular and goal-based error metrics are considered in this algorithm to locate some regions to be refined. A mapping algorithm derived by moment conservation is developed to pass the angular solution between spatial regions with different quadrature sets. The proposed method is applied to some test problems that demonstrate the ability of this hp-angular adaptivity to resolve complex fluxes with relatively few angular unknowns. Results illustrate that a reduction to approximately 1/50 in quadrature ordinates for a given accuracy compared with uniform angular discretization. This method therefore offers a highly efficient angular adaptivity for investigating difficult particle transport problems.
Xinyue Zhang,Bushi Dai,Shucheng Ren,Zenan Hu,Xin Zheng,Yao Wang,Hongbin Sun,Dun Niu,Linshan Wang 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.5
Due to the complexity of the contaminations in wastewater, a universal adsorbent that takes many sorts of pollutant is desired. A multi-functioning magnetic Fe3O4-cored magnesium-aluminum layered double oxide (Fe3O4@LDO) composite was prepared and employed as an adsorbent for removing F-, Sb(III) and MO from water, respectively, which are three typical contaminants with different molecule sizes as water contamination. The effect of pH contact time and initial concentrations of pollutants on the removal rates of each contaminant were investigated. Fe3O4@LDO composite showed excellent adsorption performance for all of the three molecules F-, Sb(III) and MO, and their maximum adsorption capacities are as high as 258, 391, and 506mg/g, respectively. The adsorption process of F-, Sb(III) and MO on Fe3O4@LDO fitted well to Langmuir model and pseudo-second-order kinetic model. The adsorption mechanisms of F-, Sb(III) and MO on Fe3O4@LDO were investigated. We discovered that iron ions diffused from Fe3O4 nanospheres contributed to the good performance of the absorbent.
Pengfei Chen,Xiaoquan Dai,Pingxing Xing,Xinyue Zhao,Qingle Zhang,Shifeng Ge,Jianxiao Si,Leihong Zhao,Yiming He 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-
Novel SnSe/g-C3N4 photocatalysts were one-step synthesized via a microwave heating assisted process in35 min with SnSe and melamine as precursors. The as-synthesized SnSe/g-C3N4 worked very well in H2evolution via photocatalysis. Under simulated sunlight, the best SnSe/g-C3N4 sample displayed a H2-production velocity of 1064 mmol g 1 h 1, which is 1.8 folds faster than that of neat g-C3N4. Similarpromotion effect was also observed under visible light. To reveal the nature behind the highphotoactivity, a thorough investigation was performed. XRD and XPS experiments proved the binaryconstitution of the composite. DRS experiment demonstrated that the addition of SnSe improved thephotoabsorption performance. N2-adsorption analysis showed that the SnSe/g-C3N4 photocatalystpresented similar surface area as g-C3N4. TEM experiments showed that some bulk SnSe werespontaneously decomposed to nanoparticles andfinely dispersed in g-C3N4 during the microwaveheating process. These SnSe nanoparticles were believed to be the active phase and constructed aheterojunction structure with g-C3N4, resulting in the enhanced charge separation. This conclusion wasconsidered as the key factor leading to the high H2-evolution performance and was further confirmed bythe PL, EIS, and PC experiments. The present work provides a feasible and rapid method for theconstruction of g-C3N4 based photocatalysts.
Li Mengkun,Xu Zhihui,Li Wei,Yang Jun,Yang Ming,Hongxin Lu,Dai Xinyu 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7
In this paper, 3D model-based interactive gamma ray shielding package (MIGSHIELD) is developed in virtual reality platform for windows operating system. In MIGSHIELD, the computational methodology is based on point kernel algorithm (PK), several key parameters of PK are obtained using new technique and new methods. MIGSHIELD has interactive capability with virtual world. The main features made in the MIGSHIELD are (i) handling of physical information from virtual world, (ii) handling of arbitrary shapes radioactive source, (iii) calculating the mean free path of gamma ray, (iv) providing interactive function between PK and virtual world, (v) making better use of PK for virtual simulation, (vi) plug and play. The developed package will be of immense use for calculations involving radiation dose assessment in nuclear safety and contributing to fast radiation simulation for virtual nuclear facilities.
Cloning and expression of a Chk1 gene in Daphnia pulex during different modes of reproduction
Xiaoge Guo,Shanliang Xu,Xuemei Yan,Wei Zhou,Xinyu Dai,Xiu Zou,Chunlin Wang,Danli Wang,Yunlong Zhao 한국유전학회 2015 Genes & Genomics Vol.37 No.9
The full-length cDNA of a Chk1 gene (DpChk1) was cloned from Daphnia pulex using RACE method. This cDNA is 1767 bp in length, consisting of a 1497 bp open reading frame encoding 498 amino acid protein. The deduced DpChk1 protein sequence contains phosphorylation sites, three conserved Ser-Gln and Thr- Gln motifs and shares 51–55 % similarity with A. pisum, M. rotundata, D. melanogaster, A. echinatior, B. terrestris, R. pulchellus and M. occidentalis, respectively. Gene expression analysis showed that Chk1 is differentially expressed in D. pulex during different reproductive modes. DpChk1 expression in sexually-reproducing females and males is significantly higher than in parthenogenetic Daphnia. Whole-mount in situ hybridization revealed that DpChk1 was expressed during two kinds of reproductive modes. In parthenogenetic females, hybridization signals were found in the antennae and thoracic limb, whereas expression levels in the corresponding sites of sexuallyreproducing females were relatively strong, DpChk1 could not be detected in the gonads of ephippial and parthenogenetic females. Taken together, these different reproductive stages and sex specific expression patterns are regulated temporally and spatially. We speculate that DpChk1 may be involved in conversion between different stages of reproduction and in sexual differentiation in D. pulex.
Xia Tong,Gee Gilbert C.,Jian Li,Liu Xinyue,Dai Jin,Shi Lu,Zhang Donglan,Chen Zhuo,Han Xuesong,Li Yan,Li Hongmei,Wen Ming,Su Dejun,Chen Liwei 한국역학회 2023 Epidemiology and Health Vol.45 No.-
Objectives: During the coronavirus disease 2019 (COVID-19) pandemic, a growing prevalence of racial and ethnic discrimination occurred when many Americans struggled to maintain healthy lifestyles. This study investigated the associations of racial and ethnic discrimination with changes in exercise and screen time during the pandemic in the United States (US). Methods: We included 2,613 adults who self-identified as non-Hispanic White, non-Hispanic Black, non-Hispanic Asian, or Hispanic from the Health, Ethnicity, and Pandemic (HEAP) study, a cross-sectional survey conducted among a nationally representative sample of US adults between October and November 2020. We assessed self-reported racial and ethnic discrimination by measuring COVID-19-related racial and ethnic bias and examined its associations with changes in exercise and screen time using multivariable logistic regression models. We analyzed data between September 2021 and March 2022.Results: COVID-19-related racial and ethnic bias was associated with decreased exercise time among non-Hispanic Asian (odds ratio [OR]=1.46; 95% confidence interval [CI], 1.13–1.89) and Hispanic people (OR=1.91; 95% CI, 1.32–2.77), and with increased screen time among non-Hispanic Black people (OR=1.94; 95% CI, 1.33–2.85), adjusting for age, gender, education, marital status, annual household income, insurance, and employment status. Conclusions: Racial and ethnic discrimination may have adversely influenced exercise and screen time changes among racial and ethnic minorities during the COVID-19 pandemic in the US. Further studies are needed to investigate the mechanisms through which racial and ethnic discrimination can impact lifestyles and to develop potential strategies to address racial and ethnic discrimination as a barrier to healthy lifestyles.