163 research outputs found
DFT, EPR and SPR insight to the relation between photocatalytic activity and nonlinearity and anisotropy ferromagnetism of Au/Co3O4/Bi2MoO6 composites
No full textThe combination of Surface Plasmon Resonance (SPR) effect with hetero-p-n structure has shown promising benefits to photocatalytic activity of catalysts. In this study, Au nanoparticles doped p-n hetero-structured Co3O4/Bi2MoO6 composites were synthesized and subjected to photocatalytic and photocurrent tests using visible light irradiation. The synthesized Au/Co3O4/Bi2MoO6 efficiently removed 97.2% of Methyl orange within 60 min, showing very good photocatalytic stability through leaching test. Colorless pollutant phenol degradation test verified the excellent photocatalytic activity of Au/Co3O4/Bi2MoO6. Possible influential factors such as electron transition, charge transfer, energy band gap, DOS, polarizability, SPR effect, oxygen vacancies and anisotropy permittivity were investigated through DFT, XPS, EPR, Z-scan, UV–visible spectra, ellipsometer spectroscopy and Mott-Schottky analysis. A reasonable degradation mechanism and possible pathway for Methyl orange were proposed based on the experimental results and DFT calculations. The doped Co3O4 provided active 3d electrons transition and charge transfer which increased carriers’ con
centration and reduced the energy band gap, while the Au SPR enhanced internal polarization and strengthened the built-in electric field, yielding strong driving force for photo-generated electrons-holes pairs separation and consumption. In addition, magnetic Co3O4 endowed sample with room-temperature ferromagnetism which was obviously strengthened by Au NPs. The magnetism of sample was beneficial for separation and recovery in photocatalytic practical applications.
Al3O4 tailored La0.8Sr0.2FeO3 crystallization in heavy metal oxide glass: synthesis, structure, and enhanced linear & nonlinear properties
No full textGlass containing magnetic nanocrystals are attractive to provide high optical linear and nonlinearity properties. In this study, we reported the synthesis of perovskite La0.8Sr0.2FeO3 nanocrystals in heavy metal oxide glass under the AlO3 tailoring. The influence of AlO3 amount to the formation of La0.8Sr0.2FeO3 nanocrystals and the influence of nanocrystals to glass structure, optical linear& nonlinear properties were thoroughly investigated. The 10 nm-nanocrystals of orthogonal La0.8Sr0.2FeO3 were synthesized by melting quenching followed with subsequent crystallization process at 400 degrees for 30 min under the tuning of AlO3. The formed La0.8Sr0.2FeO3 were well distributed in matrix without aggregation. Structure and chemical valence study revealed the aluminum abnormality effect and the Sr2+ induced multi-valence states of Fe ions and oxygen vacancies in La0.8Sr0.2FeO3 lattice. Such modification clearly influenced the optical ab-sorption, refractive index, polarizability, energy band gap shrinkage and nonlinearity. Physical parameters such as oxygen packing density, free volume etc. were calculated to confirm the influence of AlO3 tailored La0.8Sr0.2FeO3 crystallization to glass. The glass with 10%AlO3 amount exhibited a large thermal stability (132 degrees), low thermal expansion coefficient (10.2 x10(-6)/K) and high BO4/AlO4 units, providing suitable environment for La0.8Sr0.2FeO3 crystallization. About 20 nm nanocrystals were formed and well distributed in glass which contributed to large nonlinearity absorption coefficient (5.19 x10(-10) m/W) and FOM (13.6 x10(3) esu cm) which much superior than from relative literatures. The obtained glass with extremely good optical linear and nonlinearity performances can be promising candidate for photonics device applications. (C) 2022 Elsevier B.V. All rights reserved
Dual p-n Z-scheme heterostructure boosted superior photoreduction CO2 to CO, CH4 and C2H4 in In2S3/MnO2/BiOCl photocatalyst
No full textThe creation of a Z-scheme heterojunction is a sophisticated strategy to enhance photocatalytic efficiency. In our study, we synthesized an In2S3/MnO2/BiOCl dual Z-scheme heterostructure by growing BiOCl nanoplates on the sheets of In2S3 nanoflowers, situated on the surface of MnO2 nanowires. This synthesis involved a combination of hydrothermal and solution combustion methods. Experiments and density functional theory (DFT) calculations demonstrated that the In2S3/MnO2/BiOCl composite exhibited notable photo reduction performance and photocatalytic stability. This was attributed to the pivotal roles of BiOCl and MnO2 in the composite, acting as auxiliaries to enhance the electronic structure and facilitate the adsorption/activation capacity of CO2 and H2O. The yield rates of CO, CH4, and C2H4 over In2S3/MnO2/BiOCl as the catalyst were 3.94, 5.5, and 3.64 times higher than those of pure In2S3, respectively. Photoelectrochemical analysis revealed that the dual Z-scheme heterostructure, with its oxygen vacancies and large surface area, enhanced CO2 absorption and active sites on the nanoflower/nanowire intersurfaces. Consequently, the dual Z-scheme charge transfer pathway provided efficient channels for boosting electron transfer and charge separation, resulting in high C2H4, CH4, and CO yields of formed and exihibits an promising photoreduction rate of CO2 to CO (51.2 μmol/g.h), CH4 (42.4 μmol/g.h) and C2H4 (63.2 μmol/g.h), respectively. DFT, in situ Diffuse reflectance infrared fourier transform spectroscopy, and temperature-programmed desorption tests were employed to verify the intermediates pathway. The study proposed a potential photocatalytic mechanism based on these findings
Baoji (City profile)
No full textBaoji was a historical town with about 7 000 people at the beginning of this century. The strategic location made it an important transport and communication node in central China. Since 1949 it has attracted many government funded industrial and transport-related projects. By the early 1990s it has become the second largest city and a regional political and economic centre in Shaanxi Province with a population of 450 000. Under the current economic reform, the city faces new challenges and has to compete with other places for private investment. The city planners are seeking new approaches to shape the future development
Olecryptotendipes melasmus Yan, Wang & Bu 2012
No full textOlecryptotendipes melasmus Yan, Wang & Bu, 2012 Olecryptotendipes melasmus Yan, Wang & Bu, 2012: 88. Specimens examined. Type material: Holotype ♂ (BDN No. 04250). CHINA: Shaanxi Province, Baoji City, Feng County, Qinling, Dongyu, 33°54'42.03"N, 106°31'21.10"E, 30. vii.1994, sweep net, W. Bu. Paratype (BDN No. 20598). CHINA: 1♂, Fujian Province, Jianning County, 26°49'51.25"N, 116°50'45.90"E, 25. ix. 2002, light trap, Z. Liu. Diagnostic characters. Thorax and legs with blackish brown spots. Anal point concave in its median portion, rounded apically, superior volsella curved basally, straight distally, with large posterolateral projection and inferior volsella with reduced lobate caudal projection. Gonostylus swollen at base, concave medially and slender to apex. Distribution. China (Palaearctic China: Shaanxi Province, Oriental China: Fujian Province).Published as part of Yan, Chuncai, Liu, Ting, Zhao, Guangjun, Shi, Yafeng & Wang, Xinhua, 2017, A new species of Olecryptotendipes Zorina from China (Diptera, Chironomidae), pp. 291-296 in Zootaxa 4299 (2) on page 295, DOI: 10.11646/zootaxa.4299.2.10, http://zenodo.org/record/83590
Midinfrared one-dimensional photonic crystal constructed from two-dimensional electride material
No full textDicalcium nitride (Ca2N) is a layered material that has been recently identified as a two-dimensional electride, based on first-principles calculations, where the electronic property and the optical complex dielectric function are studied using density functional theory. We find that the optical permittivity tensor is highly anisotropic, and Ca2N possesses metallic characters when the in-plane dielectric function is negative in midinfrared frequency. In addition, the enhanced midinfrared transmission property and the field distribution of one-dimensional photonic crystals composed of alternating Ca2N layers and the dielectric material are theoretically studied using the transfer-matrix method. It is found that the Ca2N photonic crystals support a series of passbands and stopbands the numbers of which increase with the thickness and the permittivity of the dielectrics. The field distributions show that the transmission resonances in the passband are attributed to the coupled Fabry-Pérot resonances of the individual reactively loaded dielectric slabs. It is also noticed that these resonances lie within certain characteristic frequency bands which are independent of the period of the photonic crystal. The low-frequency edge of the passband is highly tunable by the thickness of the electride material and the dielectric material, the permittivity of the dielectric layer, while the high-frequency edge is insensitive to the electride material thickness. Moreover, the first band gap in lower frequency is almost omnidirectional and polarization insensitive. When defect layers are introduced, the twin defect modes are found, and the frequency and the frequency interval of the two defect modes can be tuned just by changing the permittivity, the thickness and the position of the defect layer, respectively. Polarization and angular insensitive absorption bands can also be obtained for the electride-dielectric photonic crystal with a reflective substrate. These properties of electride material photonic crystals have potential applications in tunable multiband filters and absorbers in the midinfrared region.</p
Paratrichocladius ater Wang et Zheng
No full text<i>Paratrichocladius ater</i> Wang <i>et</i> Zheng <p>(Fig. 2 A–K)</p> <p> <i>Paratrichocladius ater</i> Wang <i>et</i> Zheng, 1990: 243; Wang 2000: 638.</p> <p> <b>Material examined. CHINA: Jilin Province</b>, Jilin City, Changbaishan Mountain (43°55’ N, 126°26’ E), alt. 1700 m, 25. vi. 1986, light trap, holotype male, Xinhua Wang (BDN No. 05384), Additional material: <b>Sichuan Province:</b> Ganzi Autonomous State, Luding County (29°55’ N, 102°14’ E), alt. 1395 m, light trap, 1 male, 7. vi. 1996, Xinhua Wang (BDN No. 12340); Ganzi Autonomous State, Yajiang County (30°02’ N, 101°01’ E), alt. 1900 m, light trap, 1 male, 6. vi. 1996, Xinhua Wang (BDN No. 12247); Wenchuan County, Yingxiu Town (31°03’ N, 103°29’ E), alt. 994 m, light trap, 2 males, 15. vii. 1987, Xinhua Wang (BDN No. 0 4571, 04577); Kangding County, Wasigou (30°03’ N, 101°57’ E), alt. 3700 m, light trap, 2 males, 15. vi. 1996, Xinhua Wang (BDN No. 23796, 23797); <b>Yunnan Province</b>: Lijiang Naxizu Autonomous County, Shizishan Mountain (26°51’ N, 100°15’ E), alt. 2400 m, 1 male, 15. vii. 2001, Xinhua Wang (BDN No. 13145); Eryuan County, Niujie Town, Meici River (26°6' N, 99°56' E), alt. 2332 m, light trap, 3 males, 2. vi. 1996, Changfa Zhou (BDN No. 0 9757, 0 9921, 09923); Dali County (25°40’ N, 100°12’ E), alt. 2300 m, light trap, 1 male, 22. v. 1996, Xinhua Wang (BDN No. 11049); <b>Ningxia Autonomous Region</b>: Wuzhong City, Tongxin County, Changshantou Farm (36°58’ N, 105°55’ E), alt. 1353 m, 2 males, 4. viii. 1987, Xinhua Wang (BDN No. 0 5387, 05388); Yinchuan City, Helan County, Helanshan Mountain (38°29’ N, 106°08’ E), alt. 1118 m, light trap, 4 males, 26. vii. 1987, Xinhua Wang (BDN No. 0 54390, 0 5397, 0 5399, 05400); <b>Shandong Province</b>: Taishan Mountain (36°15’ N, 117°02’ E), alt. 1500 m, 3 males, 26. v. 1994, Xinhua Wang (BDN No. 0 3251, 0 3245, 03247),; <b>Hebei Province</b>: Weichang County, Qipan Town (42°10’ N, 117°57’ E), alt. 1800 m, light trap, 3 males, 16. vii. 2001, Yuhong Guo (BDN No. 23352, 23350, 23388); Chengde City, West Railway Station (40°58’ N, 117°57’ E), alt. 360 m, light trap, 4 males, 12. vii. 2001, Yuhong Guo (BDN No. 23325, 23326, 23327, 23328); <b>Henan Province</b>: Xinyang County, Jigongshan Mountain (31°48’ N, 114°05’ E), alt. 690 m, light trap, 9. vii. 1997, 1 male, Xinhua Wang (BDN No. 13145); <b>Shananxi Province</b> Baoji City, Feng County, Qinling (33°58’ N, 106°46’ E), alt. 1302 m, sweeping, 1 male, 27. vii. 1994, Wenjun Bu (BDN No. 08282); <b>Gansu Province</b>: Tianshui City, Maijishan Mountain (34°21’ N, 106°00’ E), alt. 1600 m, 7. viii. 1986, 1 male, Xinhua Wang (BDN No. 16178).</p> <p> <b>Diagnostic characters.</b> The adult male can be separated from other members of the genus by having high AR; humeral pit well developed, almost rectangular; inferior volsella bilobed, and gonostylus with crista dorsalis. It is similar to <i>P. t a m a a t e r</i> Sasa in the shape of inferior volsella, but differ in the higher antennal ratio of 1.6–2.0, 1.8 as compared to 1.14 in <i>P. tamaater</i>; in the coloration and in the chaetotaxy of the abdomen.</p> <p> <b>Additions to description (n = 31).</b> Total length 2.7–3.6, 3.1 mm. Wing length 1.4–2.0, 1.8 mm. Total length/ wing length 1.7–2.0, 1.8. Wing length/ length of profemur 2.3–2.8, 2.6. Temporal setae 8–11. Tentorium 140–180, 159 µm long, 35–45, 39 µm wide. Stipes 140–160, 155 µm long; 8–10, 9 µm wide. Palpomere 5/ 3 1.4–1.9, 1.7. Dorsocentrals 15–18, 16 setae; prealars 4–5. Scutellum with 4–8, 6 setae. Squama with 11–15, 13 fringe setae. Sensilla chaetica 10–14, 12 on ta1 of P3. Laterosternite IX with 6–8, 7 long setae. Phallapodeme 65–80, 75 µm long, transverse sternapodeme 100–195, 135 µm long, with oral projections. Gonocoxite 185–238, 215 µm long. Gonostylus 78–108, 88 µm long, with crista dorsalis. Megaseta 10–15, 13 µm long. HR 2.1–3.1, 2.5, HV 3.1–3.5, 3.3.</p> <p> <b>Distribution.</b> The Chinese specimen was collected in Ningxia Autonomous Regions; Jilin, Liaoning, Hebei, Henan, Shandong and Gansu Provinces (Palaearctic China); Shananxi (Baoji City), Yunnan and Sichuan Provinces (Oriental China). This is the first record from Oriental China.</p> <p> <b>Remarks.</b> The shape of the inferior volsella varies among different localities (Fig. 2 A–K).</p>Published as part of <i>Fu, Yue, Saether, Ole A. & Wang, Xinhua, 2012, A review of Paratrichocladius Santos Abreu from the Sino-Indian Region (Diptera: Chironomidae: Orthocladiinae), pp. 453-482 in Zootaxa 3478</i> on pages 456-457, DOI: <a href="http://zenodo.org/record/209364">10.5281/zenodo.209364</a>
Electronic and hyperbolic dielectric properties of ZrS<sub>2</sub>/HfS<sub>2</sub> heterostructures
No full textIn this paper we investigate the electronic and optical dielectric properties of lateral and vertical heterostructures composed of two-dimensional (2D) ZrS2 and HfS2 monolayers based on density functional theory. First, we show that the bulk and monolayer ZrS2 and HfS2 as well as the vertical (ZrS2)m/(HfS2)n heterostructures are in direct band gap semiconductors, while the lateral heterostructures exhibit an indirect to direct bandgap transition. Then we demonstrate that the optical properties of the bulk and monolayer HfS2 and ZrS2are strongly anisotropic, for the bulk HfS2 and ZrS2, the in-plane components of the dielectric function is negative in a certain frequency band, where they can work as naturally hyperbolic metamaterials (HMMs). Interestingly, the vertical heterostructures also possess a hyperbolic region, whose position and width can be tunable with the thickness ratio of constituents. It is also found that the (ZrS2)/(HfS2) vertical heterostructures can enhance spontaneous emission and about 100-fold improvement of the Purcell factor is obtained. These results prove the feasibility of 2D material heterostructures to realize tunable hyperbolic metamaterials, the heterostructures present a promising opportunity for the practical applications in light-generation technologies
Low-Carbon Impact of Urban Rail Transit Based on Passenger Demand Forecast in Baoji
No full textThere are increasing traffic pollution issues in the process of urbanization in many countries; urban rail transit is low-carbon and widely regarded as an effective way to solve such problems. The passenger flow proportion of different transportation types is changing along with the adjustment of the urban traffic structure and a growing demand from passengers. The reduction of carbon emissions brought about by rail transit lacks specific quantitative research. Based on a travel survey of urban residents, this paper constructed a method of estimating carbon emissions from two different scenarios where rail transit is and is not available. This study uses the traditional four-stage model to forecast passenger volume demand at the city level and then obtains the basic target parameters for constructing the carbon emission reduction model, including the trip origin-destination (OD), mode, and corresponding distance range of different modes on the urban road network. This model was applied to Baoji, China, where urban rail transit will be available from 2023. It calculates the changes in carbon emission that rail transit can bring about and its impact on carbon emission reductions in Baoji in 2023
Low-Carbon Impact of Urban Rail Transit Based on Passenger Demand Forecast in Baoji
No full textThere are increasing traffic pollution issues in the process of urbanization in many countries; urban rail transit is low-carbon and widely regarded as an effective way to solve such problems. The passenger flow proportion of different transportation types is changing along with the adjustment of the urban traffic structure and a growing demand from passengers. The reduction of carbon emissions brought about by rail transit lacks specific quantitative research. Based on a travel survey of urban residents, this paper constructed a method of estimating carbon emissions from two different scenarios where rail transit is and is not available. This study uses the traditional four-stage model to forecast passenger volume demand at the city level and then obtains the basic target parameters for constructing the carbon emission reduction model, including the trip origin-destination (OD), mode, and corresponding distance range of different modes on the urban road network. This model was applied to Baoji, China, where urban rail transit will be available from 2023. It calculates the changes in carbon emission that rail transit can bring about and its impact on carbon emission reductions in Baoji in 2023.</jats:p
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