A narrow linewidth Faraday anomalous dispersion optical filter(FADOF)with reflection configuration is achieved for the first time based on the cesium(Cs)ground state 6S_(1/2) to the excited state 6P_(3/2) transition a...A narrow linewidth Faraday anomalous dispersion optical filter(FADOF)with reflection configuration is achieved for the first time based on the cesium(Cs)ground state 6S_(1/2) to the excited state 6P_(3/2) transition at 852 nm.Compared with the conventional FADOF with transmission configuration,reflection-type FADOF can greatly improve the transmittance of optical filter under the same experimental parameters,because it allows signal light to go and return through the atomic vapor cell.In our experiment,peak transmittance at Cs 6S_(1/2) F=4-6P_(3/2) transition is 81%for the reflection-type FADOF,and while 54%for the transmission-type FADOF when the temperature of Cs vapor cell and the axial magnetic field are 60℃and 19 G.The idea of this reflection-type FADOF design has the potential to be applied to the FADOF operating between two excited states to obtain higher transmittance.展开更多
Based on field research data of farmers in Zhejiang Province, the authors analyzed factors influencing farmers' participation in forest farmers cooperatives (hereafter referred to as FFCs) by the binary logistic r...Based on field research data of farmers in Zhejiang Province, the authors analyzed factors influencing farmers' participation in forest farmers cooperatives (hereafter referred to as FFCs) by the binary logistic regression model. Results show that understanding of farmers about cooperatives has a great influence on their behavior of participation in FFCs. Besides, educational level of householders and existing member scale of cooperatives also have significant influence on farmers' behavior of participation in cooperatives. Therefore, it is required to strengthen propaganda of cooperatives, deepen their understanding of cooperatives; cultivate new high quality farmers to provide talents for development of cooperatives; establish incentive mechanism to encourage farmers to participate in cooperatives.展开更多
The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fi...The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.展开更多
In this study,Fe3 O4@SiO2@ZnO:La microspheres were successfully prepared.The microspheres have the advantages of both ZnO doped with La and the Fe3 O4@SiO2 structure such that the former improves the photocatalytic ac...In this study,Fe3 O4@SiO2@ZnO:La microspheres were successfully prepared.The microspheres have the advantages of both ZnO doped with La and the Fe3 O4@SiO2 structure such that the former improves the photocatalytic activity of ZnO and the latter can be reused.The X-ray diffraction(XRD),a field emission scanning electron microscope(SEM),a field emission transmission electron microscope(TEM),X-ray photoelectron spectroscopy(XPS),and a vibrating sample magnetometer(VSM)were used to characterize Fe3 O4@SiO2@ZnO:La microspheres.Methyl orange was used as the model molecule to study the effect of the Zn2+concentration and the doping amount of La on the photocatalytic activity of Fe3 O4@SiO2@ZnO:La microspheres.Results show that in the synthesis of Fe3 O4@SiO2@ZnO:La microspheres,photocatalytic activity of the microspheres is enhanced first and weakened later with the increase of Zn2+concentration.In the La doping process,the photocatalytic activity of Fe3 O4@SiO2@ZnO:La microspheres is enhanced with the increase in the La doping amount.The magnetic photocatalysts not only have high photocatalytic activity,but also can be reused.After being reused five times,the photocatalyst’s degradation rate of methyl orange is still as high as 81%,which shows that magnetic photocatalysts have prospective wider applications in photocatalytic degradation of dye wastewater.展开更多
Micro-gyroscopes using micro-electro-mechanical system(MEMS)and micro-optoelectro-mechanical system(MOEMS)are the new-generation and recently well-developed gyroscopes produced by the combinations of the traditional g...Micro-gyroscopes using micro-electro-mechanical system(MEMS)and micro-optoelectro-mechanical system(MOEMS)are the new-generation and recently well-developed gyroscopes produced by the combinations of the traditional gyroscope technology and MEMS/MOEMS technologies.According to the working principle and used materials,the newly-reported micro-gyroscopes in recent years include the silicon-based micromechanical vibratory gyroscope,hemispherical resonant gyroscope,piezoelectric vibratory gyroscope,suspended rotor gyroscope,microfluidic gyroscope,optical gyroscope,and atomic gyroscope.According to different sensitive structures,the silicon-based micromechanical vibratory gyroscope can also be divided into double frame type,tuning fork type,vibrating ring type,and nested ring type.For those micro-gyroscopes,in recent years,many emerging techniques are proposed and developed to enhance different aspects of performances,such as the sensitivity,angle random walk(ARW),bias instability(BI),and bandwidth.Therefore,this paper will firstly review the main performances and applications of those newly-developed MEMS/MOEMS gyroscopes,then comprehensively summarize and analyze the latest research progress of the micro-gyroscopes mentioned above,and finally discuss the future development trends of MEMS/MOEMS gyroscopes.展开更多
基金the National Natural Science Foundation of China(Grant Nos.61975102 and 11974226)the National Key Research and Development Program of China(Grant No.2017YFA0304502)+1 种基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China(Grant No.2019L0101)the Natural Science Foundation of Shanxi Province,China(Grant No.20210302123437).
文摘A narrow linewidth Faraday anomalous dispersion optical filter(FADOF)with reflection configuration is achieved for the first time based on the cesium(Cs)ground state 6S_(1/2) to the excited state 6P_(3/2) transition at 852 nm.Compared with the conventional FADOF with transmission configuration,reflection-type FADOF can greatly improve the transmittance of optical filter under the same experimental parameters,because it allows signal light to go and return through the atomic vapor cell.In our experiment,peak transmittance at Cs 6S_(1/2) F=4-6P_(3/2) transition is 81%for the reflection-type FADOF,and while 54%for the transmission-type FADOF when the temperature of Cs vapor cell and the axial magnetic field are 60℃and 19 G.The idea of this reflection-type FADOF design has the potential to be applied to the FADOF operating between two excited states to obtain higher transmittance.
基金Supported by the Project of Food and Agricultural Organization of the United Nations(GCP/CPR/038/200906)the Project of Zhejiang Province Forestry Department(07A13)
文摘Based on field research data of farmers in Zhejiang Province, the authors analyzed factors influencing farmers' participation in forest farmers cooperatives (hereafter referred to as FFCs) by the binary logistic regression model. Results show that understanding of farmers about cooperatives has a great influence on their behavior of participation in FFCs. Besides, educational level of householders and existing member scale of cooperatives also have significant influence on farmers' behavior of participation in cooperatives. Therefore, it is required to strengthen propaganda of cooperatives, deepen their understanding of cooperatives; cultivate new high quality farmers to provide talents for development of cooperatives; establish incentive mechanism to encourage farmers to participate in cooperatives.
基金Supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+2 种基金the Natural Science Foundation of Sichuan Province,China(No.2023NSFSC0961)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06)the Postgraduate Innovation Fund Project by Southwest University of Science and Technology,China(No.24ycx2027).
文摘The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.
基金Project supported by the National Natural Science Foundation of China(31560466,20968005)。
文摘In this study,Fe3 O4@SiO2@ZnO:La microspheres were successfully prepared.The microspheres have the advantages of both ZnO doped with La and the Fe3 O4@SiO2 structure such that the former improves the photocatalytic activity of ZnO and the latter can be reused.The X-ray diffraction(XRD),a field emission scanning electron microscope(SEM),a field emission transmission electron microscope(TEM),X-ray photoelectron spectroscopy(XPS),and a vibrating sample magnetometer(VSM)were used to characterize Fe3 O4@SiO2@ZnO:La microspheres.Methyl orange was used as the model molecule to study the effect of the Zn2+concentration and the doping amount of La on the photocatalytic activity of Fe3 O4@SiO2@ZnO:La microspheres.Results show that in the synthesis of Fe3 O4@SiO2@ZnO:La microspheres,photocatalytic activity of the microspheres is enhanced first and weakened later with the increase of Zn2+concentration.In the La doping process,the photocatalytic activity of Fe3 O4@SiO2@ZnO:La microspheres is enhanced with the increase in the La doping amount.The magnetic photocatalysts not only have high photocatalytic activity,but also can be reused.After being reused five times,the photocatalyst’s degradation rate of methyl orange is still as high as 81%,which shows that magnetic photocatalysts have prospective wider applications in photocatalytic degradation of dye wastewater.
基金This work was supported in part by the National Natural Science Foundation of China(Grant Nos.U2230206,12074058,62371106,and 61971113)the National Key Research and Development Program for Young Scientists(Grant No.2022YFA1405900)+2 种基金the Joint Fund of Ministry of Education(Grant No.8091B022126)the Fundamental Enhancement Program Technology Area Fund(Grant No.2021-JCJQ-JJ-0667)Sichuan Provincial Science and Technology Planning Program of China(Grant Nos.2021YJ0089,2022YFG0230,and 2023YFG0040).
文摘Micro-gyroscopes using micro-electro-mechanical system(MEMS)and micro-optoelectro-mechanical system(MOEMS)are the new-generation and recently well-developed gyroscopes produced by the combinations of the traditional gyroscope technology and MEMS/MOEMS technologies.According to the working principle and used materials,the newly-reported micro-gyroscopes in recent years include the silicon-based micromechanical vibratory gyroscope,hemispherical resonant gyroscope,piezoelectric vibratory gyroscope,suspended rotor gyroscope,microfluidic gyroscope,optical gyroscope,and atomic gyroscope.According to different sensitive structures,the silicon-based micromechanical vibratory gyroscope can also be divided into double frame type,tuning fork type,vibrating ring type,and nested ring type.For those micro-gyroscopes,in recent years,many emerging techniques are proposed and developed to enhance different aspects of performances,such as the sensitivity,angle random walk(ARW),bias instability(BI),and bandwidth.Therefore,this paper will firstly review the main performances and applications of those newly-developed MEMS/MOEMS gyroscopes,then comprehensively summarize and analyze the latest research progress of the micro-gyroscopes mentioned above,and finally discuss the future development trends of MEMS/MOEMS gyroscopes.