Fu X.,Beijing National Day School |
Liu E.,Beijing Normal University
American Biology Teacher | Year: 2016
We designed a course based on inquiry learning using WISE, an online inquiry-based science environment platform, and the 5E instructional model. This article summarizes guidelines used in designing the course, analyses of student needs and school environment, setting of course objectives, modification of materials, and evaluation of student performance. A "Healthy Life" course based on those guidelines was implemented, along with a teacher-training workshop, in two schools, and pretests and posttests were administered to evaluate the achievements of the project participants. The results showed that the participants had constructed scientific concepts and improved their level of cognitive knowledge. An efficiency questionnaire and semistructured interviews demonstrated the effectiveness of the course, thus indicating that we should share the guidelines and features of the Healthy Life course with other course designers and teachers. © 2016 National Association of Biology Teachers. All rights reserved.
Wen S.Y.,Beijing Normal University |
Sun X.C.,Chinese Ministry of Water Resources |
Ma M.L.,Beijing National Day School
Materials Science Forum | Year: 2014
Five types of TiO2-bentonite catalyst, #1, #2, #3, #4, and #5, were prepared separately using hydrochloric acid, nitric acid and perchloric acid by the sol-gel method. The original concentration of sodium dodecyl benzene sulfonate (SDBS) in the aqueous solutions was 20 mg/L. The amounts of SDBS degraded by #1, #2, #3, #4 and #5 under a 6 W ultraviolet lamp were compared, the influences of #1 and #2 on the chemical oxygen demand (COD) of the aqueous solutions studied. And the influences of the initial pH on the degradation of SDBS and on the COD of aqueous solutions were investigated. The results showed as the following. (1) When the catalyst input was 0.5‰ and the solutions were irradiated with a 6 W ultraviolet lamp, 81.0%, 90.5% 47.5%, 39.5% and 26.5% of the SDBS in the aqueous solutions was degraded within 2 hours by catalysts #1, #2, #3, #4 and #5, respectively. The COD was reduced by 8.81% and 50.84%by catalysts #1 and #2, respectively. (2) Under an ultraviolet lamp, 94.5% and 99.3% of the SDBS in the aqueous solutions was degraded and 33.59% and 96.93% of the COD was reduced within 6 hours by catalysts #1 and #2, respectively. TiO2-bentonite catalyst #2 was the best based on the effects on the degradation of SDBS and on the reduction of the COD of aqueous solutions. Using nitric acid was better than using hydrochloric acid or perchloric acid for the preparation of TiO2-bentonite. (3) Under the same conditions (20 mg/L SDBS, 20°C, ultraviolet light irradiation time of 2 h, electromagnetic mixing, 0.5‰ input of TiO2-bentonite #2), 90.3% and 90.5% of SDBS was degraded by TiO2-bentonite #2 at pHs 6 and 8, respectively. The optimal pH range for SDBS degradation was 6~8. The COD was reduced by 59.5% and 63.5% pHs 4 and 6, respectively. The optimal pH range for the COD reduction was 4 ~ 6. The pH had a clear effect on SDBS degradation and the COD of the aqueous solutions. © (2014) Trans Tech Publications, Switzerland.
Fan C.,Beijing University of Posts and Telecommunications |
Zhao T.,Beijing National Day School |
Wu Y.,Beijing University of Posts and Telecommunications |
Gong N.,Beijing University of Posts and Telecommunications
Proceedings - 2016 International Conference on Networking and Network Applications, NaNA 2016 | Year: 2016
This work analyzes the methods of utilizing LDA (Latent Dirichlet Allocation) model to find implicit semantic dimensionality. With the analysis we propose a modified LDA model, E-LDA, according to the timeliness and topic's variation. In E-LDA, time dimension and topic dimension are incorporated. E-LDA firstly discretizes document sets and then analyzes the latent semantic information in discrete time slices. We count the number of topics with known information in current time slice, and apply the E-LDA model to their corresponding document sets. Experimental results show that the proposed E-LDA can classify topic related documents of Web information according to latent semantic, and furthermore, it can accomplish analyzing the trend of topics with their distribution and popularity at different time. © 2016 IEEE.
Li J.,CAS Institute of Process Engineering |
Li J.,Xiangtan University |
Mu Y.,CAS Institute of Process Engineering |
Mu Y.,Shenyang Institute of Chemical Technology |
And 5 more authors.
Huagong Xuebao/CIESC Journal | Year: 2013
A series of V2O5-WO3- TiO2/SO4 2- catalysts were prepared with the impregnation method using nano-TiO2 support sulfated according to three different orders of sulfating TiO2 support and with different acid amounts. Characterization of the catalysts with XRD, BET, FT-IR and TG-DTG showed that sulfating the catalyst support decreased the specific surface area of the resulting catalyst but did not vary its crystal form. Sulfation caused as well strong interactions between WO3 and the sulfate of the loaded active component. Temperature-programmed activity tests demonstrated further that sulfation increased catalytic activity by increasing the acidity of the catalyst at 120-400°C. This was confirmed also with NH3-TPD for the prepared V/Ti denitration catalysts. © All Rights Reserved.
Li Y.-F.,CAS Institute of High Energy Physics |
Zhao J.,CAS Institute of High Energy Physics |
Qu Y.,CAS National Center for Nanoscience and Technology |
Gao Y.,CAS Institute of High Energy Physics |
And 5 more authors.
Nanomedicine: Nanotechnology, Biology, and Medicine | Year: 2015
Nanotoxicology studies the interactions of engineered nanomaterials with biological systems. Traditional in vitro and in vivo toxicological assays have been successfully employed. However, the toxicological mechanisms of nanoparticles might not be the same as those incurred in traditional molecular toxicology. Furthermore, how to realize in situ and real time measurements especially in the biological microenvironment is still a challenge. Synchrotron radiation, which is highly polarized and tunable, has been proved to play an indispensible role for nanotoxicology studies. In this review, the role of synchrotron radiation techniques is summarized in screening physicochemical characteristics, in vitro and in vivo behaviors, and ecotoxicological effects of engineered nanomaterials. From the Clinical Editor: The rapid gain in popularity of nanomaterials has also raised the concern of nanotoxicity, which needs to be assessed and addressed. In this comprehensive review, the authors outlined the underlying principles of using synchrotron radiation techniques for nanotoxicology studies and also in other scientific fields. © 2015 Elsevier Inc.
Liu C.,Shandong University |
Zhang X.-Y.,Shandong University |
Wen X.-R.,Beijing National Day School |
Shi M.,Shandong University |
And 2 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2016
A yellow-pigmented, rod-shaped, non-flagellated, aerobic and Gram-reaction-negative bacterium, designated strain SM1212T, was isolated from intertidal sand of Kongsfjorden, Svalbard. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1212T constituted a distinct lineage within the family Flavobacteriaceae. It shared highest 16S rRNA gene sequence similarities with the type strains of Bizionia echini (96.0%), Lacinutrix jangbogonensis (95.8%) and Psychroserpens damuponensis (95.7%) and,95.6% sequence similarity with other recognized species in the family Flavobacteriaceae. The strain grew at 4–35 8C and with 0–6.0% (w/v) NaCl. It hydrolysed gelatin, DNA, starch and Tween 80 but did not reduce nitrate to nitrite. The major cellular fatty acids were anteiso- C15: 0, iso-C15: 0, iso-C15: 1 G, anteiso-C15: 1 A, iso-C15: 0 3-OH, C17: 0 2-OH and iso- C17: 0 3-OH and the major respiratory quinone was menaquinone MK-6. Polar lipids included phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminophospholipid, three unidentified aminolipids and nine unidentified lipids. The genomic DNA G+C content of strain SM1212T was 36.6 mol%. On the basis of data from this polyphasic study, strain SM1212T represents a novel species in a new genus in the family Flavobacteriaceae, for which the name Arcticiflavibacter luteus gen. nov., nov., sp. nov. is proposed. The type strain of Arcticiflavibacter luteus is SM1212T (=MCCC 1K00234T=KCTC 32514T). © 2015 IUMS.
Tan Y.-Q.,University of Chinese Academy of Sciences |
Yu Y.,University of Chinese Academy of Sciences |
Hao Y.-M.,University of Chinese Academy of Sciences |
Dong S.-Y.,Beijing National Day School |
Yang Y.-W.,Beijing National Day School
Materials Research Bulletin | Year: 2013
A new type of tungsten bronze ceramic Ba5NdCu 1.5Nb8.5O30-δ has been prepared by a conventional solid-state reaction technique. Its structural, dielectric properties were investigated. Rietveld analysis shows that Ba 5NdCu1.5Nb8.5O30-δ has a single-phase tetragonal (space group P4bm and lattice constants a = b = 12.4961(4), c = 3.9426(8), V = 615.66(4)3) tungsten bronze structure. The occupations of sites A and B are quite interesting. A1 sites are fully disordered occupied by Ba ions and Nd ions and A2 sites for Ba ions only, while B-sites are equal for both Cu and Nb ions to occupy. This material exhibits an obvious relaxation behavior in the 213-573 K temperature range. The dielectric constants have been fitted by the modified Curie-Weiss law and all the estimated γ values are close to 2, confirming the typical relaxor ferroelectric behavior. The disorders of Ba2+ or Nd3+ in A1 sites and Nb5+, Cu2+ in B sites induced by the oxygen vacancies may contribute to this dielectric behavior. © 2013 Elsevier Ltd.
Hao Y.,University of Chinese Academy of Sciences |
Wang Z.,University of Chinese Academy of Sciences |
Gou J.,University of Chinese Academy of Sciences |
Dong S.,Beijing National Day School
Arabian Journal of Chemistry | Year: 2015
A new kind of adsorbent graphene oxide nanocomposite (GO-Fe3O4) for removal of Chrysoidine Y was synthesized using the modified Hummers method and co-precipitation. The synthesized GO-Fe3O4 was used as an adsorbent for the removal of Chrysoidine Y from aqueous solution. The effect of initial pH on the adsorption of Chrysoidine Y onto GO-Fe3O4 has been investigated. The adsorption kinetics, isotherm and thermodynamics also have been evaluated. The adsorption was strongly dependent on the pH of medium. The studies on the adsorption revealed that the adsorption process obeyed the Pseudo-second order kinetics model, and the rate-limiting step might be chemical sorption. And the Langmuir isotherm was applicable to describe the adsorption process. This hybrid showed a good performance for the removal of Chrysoidine Y from aqueous solution with an adsorption capacity of 344.83mgg-1 at room temperature, and could be easily removed from solution using a hand-held magnet in 10min. Moreover, the adsorption mechanism was discussed and thermodynamic parameters were determined. Thermodynamic parameters indicated that the adsorption process was exothermic and spontaneous. Above all, the removal efficiency of GO-Fe3O4 was still kept at 96.0% when the concentration of dye was 100mgL-1 in polluted river. This work shows that GO-Fe3O4 is a suitable and efficient adsorbent in the removal of Chrysoidine Y from aqueous solution. © 2015 The Authors.
PubMed | University of Chinese Academy of Sciences, CAS Institute of Biophysics, Beijing National Day School, CAS Institute of High Energy Physics and Shandong Maternity and Child Care Hospital
Type: | Journal: Environmental pollution (Barking, Essex : 1987) | Year: 2016
Mercury (Hg) is a global pollutant that poses a serious threat to human and the environment. Rice was found as an important source for human exposure to Hg in some areas. In this study, the transportation and transformation of IHg and MeHg in rice plants exposed to IHg or MeHg were investigated. The IHg and MeHg concentrations in rice roots and shoots collected every five days were analyzed by HPLC-ICP-MS and SR-XANES. When exposed to MeHg, the percent of IHg in rice roots and shoots increased while MeHg decreased significantly, suggesting prominent demethylation of MeHg occurred. However no notable MeHg was found in both roots and shoots of rice plant when exposed to IHg. SR-XANES analysis further confirmed the demethylation of MeHg with rice. This study provides a new finding that demethylation of MeHg could occur in growing rice, which may be a self-defense process of rice plant.
PubMed | CAS Institute of Process Engineering, Beijing National Day School and City University of Hong Kong
Type: Journal Article | Journal: Nanoscale research letters | Year: 2016
Growing high-quality and low-cost GaAs nanowires (NWs) as well as fabricating high-performance NW solar cells by facile means is an important development towards the cost-effective next-generation photovoltaics. In this work, highly crystalline, dense, and long GaAs NWs are successfully synthesized using a two-source method on non-crystalline SiO2 substrates by a simple solid-source chemical vapor depositionmethod. The high V/III ratio and precursor concentration enabled by this two-source configuration can significantly benefit the NW growth and suppress the crystal defect formation as compared with the conventional one-source system. Since less NW crystal defects would contribute fewer electrons being trapped by the surface oxides, the p-type conductivity is then greatly enhanced as revealed by the electrical characterization of fabricated NW devices. Furthermore, the individual single NW and high-density NW parallel arrays achieved by contact printing can be effectively fabricated into Schottky barrier solar cells simply by employing asymmetric Ni-Al contacts, along with an open circuit voltage of ~0.3V. All these results indicate the technological promise of these high-quality two-source grown GaAs NWs, especially for the realization of facile Schottky solar cells utilizing the asymmetric Ni-Al contact.