Micro-honeycomb ceramics were successfully fabricated through brush-coating with cloth fabric as pore-forming agent. The influence of pore-forming agent and slurry’s moisture content on the micro-honeycomb ceramics w...Micro-honeycomb ceramics were successfully fabricated through brush-coating with cloth fabric as pore-forming agent. The influence of pore-forming agent and slurry’s moisture content on the micro-honeycomb ceramics was investigated. The results indicated that micro-honeycomb ceramics made from pore-forming agent cloth fabric with fibre diameter of 100 μm and slurry with 45% （mass fraction） moisture content have the porosity of 65% （volume fraction）, bending strength of 24.3 MPa, pore size of about 100 μm, cell wall thickness of about 50 μm and porosity of 1131 pore/cm2. It was suggested that the pore size and the porosity could be adjusted using the pore-forming agent and moisture content of the slurry respectively.展开更多
The Hainan Peacock Pheasant (Polyplectron katsumatae),the smallest allied species of somber forest peacock pheasants among the taxa of Polyplectron spp.,is a rare tropical forest bird endemic to China,and distributed ...The Hainan Peacock Pheasant (Polyplectron katsumatae),the smallest allied species of somber forest peacock pheasants among the taxa of Polyplectron spp.,is a rare tropical forest bird endemic to China,and distributed only in the mountainous region of central and southwestern Hainan Island dominated by evergreen broadleaf forests.By integrating references and unpublished data based on our field surveys,we presented information on species status,distribution and population,habitat and home range,breeding ecology and conservation of the Hainan Peacock Pheasant.Future investigation should focus on its life history traits in relation to vulnerability.Considering its limited distribution and small population size,it has recently been recognized as "Endangered" by the IUCN Red List to prevent loss of this island endemic.展开更多
The purpose of the research is to assess the sound absorption performance(SAP)of acoustic metamaterials made of double-layer Nomex honeycomb structures in which a micro-orifice corresponds to a honeycomb unit.For this...The purpose of the research is to assess the sound absorption performance(SAP)of acoustic metamaterials made of double-layer Nomex honeycomb structures in which a micro-orifice corresponds to a honeycomb unit.For this purpose,the influences of structural parameters on the SAP of acoustic metamaterials were investigated by using experimental testing and a validated theoretical model.In addition,the sandwich structure was optimized by the genetic algorithm.The research shows that the panel thickness and micro-orifice diameter mainly affect the second resonant frequency and second peak sound absorption coefficient(SAC)of the structure.The unit cell size is found to influence the first and second resonant frequencies and two peaks of the SAC.An extremely low side-length of the honeycomb core decreases the SAP of the structure for low-frequency noise signals.Additionally,the sandwich structure presents a better SAP when the diameter of micro-orifices on the front micro-perforated panel(MPP)exceeds that of the back MPP.The sandwich structure shows better noise reduction performance after the optimization aiming at the noise frequency outside trains.展开更多
Heterogeneous catalysts with ultra-small clusters and atomically dispersed(USCAD)active sites have gained increasing attention in recent years.However,developing USCAD catalysts with high-density metal sites anchored ...Heterogeneous catalysts with ultra-small clusters and atomically dispersed(USCAD)active sites have gained increasing attention in recent years.However,developing USCAD catalysts with high-density metal sites anchored in porous nanomaterials is still challenging.Here,through the template-free S-assisted pyrolysis of low-cost Fe-salts with melamine(MA),porous alveolate Fe/g-C3N4 catalysts with high-density(Fe loading up to 17.7 wt%)and increased USCAD Fe sites were synthesized.The presence of a certain amount of S species in the Fe-salts/MA system plays an important role in the formation of USCAD S-Fe-salt/CN catalysts;the S species act as a"sacrificial carrier"to increase the dispersion of Fe species through Fe-S coordination and generate porous alveolate structure by escaping in the form of SO2 during pyrolysis.The S-Fe-salt/CN catalysts exhibit greatly promoted activity and reusability for degrading various organic pollutants in advanced oxidation processes compared to the corresponding Fe-salt/CN catalysts,due to the promoted accessibility of USCAD Fe sites by the porous alveolate structure.This S-assisted method exhibits good feasibility in a large variety of S species(thiourea,S powder,and NH4SCN)and Fe salts,providing a new avenue for the low-cost and large-scale synthesis of high-density USCAD metal/g-C3N4 catalysts.展开更多
基金Project (2011WK4013) supported by the Basic Research Program of Hunan Provincial Science and Technology Department, ChinaProject (K1003031-11) supported by the Major Program for the Fundamental Research of Changsha Science and Technology Bureau, China
文摘Micro-honeycomb ceramics were successfully fabricated through brush-coating with cloth fabric as pore-forming agent. The influence of pore-forming agent and slurry’s moisture content on the micro-honeycomb ceramics was investigated. The results indicated that micro-honeycomb ceramics made from pore-forming agent cloth fabric with fibre diameter of 100 μm and slurry with 45% （mass fraction） moisture content have the porosity of 65% （volume fraction）, bending strength of 24.3 MPa, pore size of about 100 μm, cell wall thickness of about 50 μm and porosity of 1131 pore/cm2. It was suggested that the pore size and the porosity could be adjusted using the pore-forming agent and moisture content of the slurry respectively.
基金supported by the NationalNatural Science Foundation of China(Nos.30860044,30360015 and39830030)by Program for New Century Excellent Talents in University(NCET-10-0111)
文摘The Hainan Peacock Pheasant (Polyplectron katsumatae),the smallest allied species of somber forest peacock pheasants among the taxa of Polyplectron spp.,is a rare tropical forest bird endemic to China,and distributed only in the mountainous region of central and southwestern Hainan Island dominated by evergreen broadleaf forests.By integrating references and unpublished data based on our field surveys,we presented information on species status,distribution and population,habitat and home range,breeding ecology and conservation of the Hainan Peacock Pheasant.Future investigation should focus on its life history traits in relation to vulnerability.Considering its limited distribution and small population size,it has recently been recognized as "Endangered" by the IUCN Red List to prevent loss of this island endemic.
基金Project(51775558)supported by the National Natural Science Foundation of ChinaProject(2019 JJ 30034)supported by the Natural Science Foundation for Excellent Youth Scholars of Hunan Province,ChinaProject(20181053303 gg)supported by the Training Objects of Young-Middle-Aged Backbone Teacher in Ordinary Universities of Hunan Province,China。
文摘The purpose of the research is to assess the sound absorption performance(SAP)of acoustic metamaterials made of double-layer Nomex honeycomb structures in which a micro-orifice corresponds to a honeycomb unit.For this purpose,the influences of structural parameters on the SAP of acoustic metamaterials were investigated by using experimental testing and a validated theoretical model.In addition,the sandwich structure was optimized by the genetic algorithm.The research shows that the panel thickness and micro-orifice diameter mainly affect the second resonant frequency and second peak sound absorption coefficient(SAC)of the structure.The unit cell size is found to influence the first and second resonant frequencies and two peaks of the SAC.An extremely low side-length of the honeycomb core decreases the SAP of the structure for low-frequency noise signals.Additionally,the sandwich structure presents a better SAP when the diameter of micro-orifices on the front micro-perforated panel(MPP)exceeds that of the back MPP.The sandwich structure shows better noise reduction performance after the optimization aiming at the noise frequency outside trains.
文摘Heterogeneous catalysts with ultra-small clusters and atomically dispersed(USCAD)active sites have gained increasing attention in recent years.However,developing USCAD catalysts with high-density metal sites anchored in porous nanomaterials is still challenging.Here,through the template-free S-assisted pyrolysis of low-cost Fe-salts with melamine(MA),porous alveolate Fe/g-C3N4 catalysts with high-density(Fe loading up to 17.7 wt%)and increased USCAD Fe sites were synthesized.The presence of a certain amount of S species in the Fe-salts/MA system plays an important role in the formation of USCAD S-Fe-salt/CN catalysts;the S species act as a"sacrificial carrier"to increase the dispersion of Fe species through Fe-S coordination and generate porous alveolate structure by escaping in the form of SO2 during pyrolysis.The S-Fe-salt/CN catalysts exhibit greatly promoted activity and reusability for degrading various organic pollutants in advanced oxidation processes compared to the corresponding Fe-salt/CN catalysts,due to the promoted accessibility of USCAD Fe sites by the porous alveolate structure.This S-assisted method exhibits good feasibility in a large variety of S species(thiourea,S powder,and NH4SCN)and Fe salts,providing a new avenue for the low-cost and large-scale synthesis of high-density USCAD metal/g-C3N4 catalysts.
