The purpose of this paper is to present a shape preserving topology optimization method to prevent the adverse effects of the mechanical deformation on the Radar Cross Section(RCS).The optimization will suppress the v...The purpose of this paper is to present a shape preserving topology optimization method to prevent the adverse effects of the mechanical deformation on the Radar Cross Section(RCS).The optimization will suppress the variation of RCS on the perfect conductor surface by structural design.On the one hand,the physical optics method is utilized to calculate the structural RCS,which is based on the surface displacement field obtained from the finite element analysis of the structure.The corresponding design sensitivities of topology optimization are derived analytically and solved by the adjoint method.On the other hand,the RCS variation and mechanical performance are taken into account simultaneously by extending a standard compliance-based topology optimization model.Two optimization formulations are discussed in an illustrative example,where the influences of upper limits of the compliance and the RCS variation are considered.Two more examples are further tested to show the ability and validity of the proposed optimization method.展开更多
Traditional triethylamine(TEA)sensors suffer from the drawback of serious cross-sensitivity due to the low charge-transfer ability of gas-sensing materials.Herein,an advanced anti-interference TEA sensor is designed b...Traditional triethylamine(TEA)sensors suffer from the drawback of serious cross-sensitivity due to the low charge-transfer ability of gas-sensing materials.Herein,an advanced anti-interference TEA sensor is designed by utilizing interfacial energy barriers of hierarchical Bi_(2)O_(3)/WO_(3) composite.Benefiting from abundant slit-like pores,desirable defect features,and amplification effect of heterojunctions,the sensor based on Bi_(2)O_(3)/WO_(3) composite with 40%Bi_(2)O_(3)(0.4-Bi_(2)O_(3)/WO_(3))demonstrates remarkable performance in terms of faster response/recovery time(1.7-fold/1.2-fold),higher response(2.1-fold),and lower power consumption(30℃-decrement)as compared with the pristine WO_(3) sensor.Furthermore,the composite sensor exhibits long-term stability,reproducibility,and negligible response towards interfering molecules,indicating the promising potential of Bi_(2)O_(3)/WO_(3) heterojunctions in anti-interference detection of low-concentration TEA in real applications.This work not only offers a rational solution to design advanced gas sensors by tuning the interfacial energy barriers of heterojunctions,but also provides a fundamental understanding of hierarchical Bi_(2)O_(3) structures in the gas-sensing field.展开更多
Integrating functional nanomaterials on nonplanar organisms has emerged as a rising technology,while significant mismatch would cause interface failure and poor durability.Herein,we demonstrate a facile strategy to as...Integrating functional nanomaterials on nonplanar organisms has emerged as a rising technology,while significant mismatch would cause interface failure and poor durability.Herein,we demonstrate a facile strategy to assemble crystalline catecholate frameworks with honeycomb lattice on seaweed-derived polysaccharide microfibers,which is expected to form biomimetic connections and maintain durable stability.By physiological coagulation,well-aligned ZnO nanoarrays are tightly attached on alginate fibers,which is fractionally adopted as sacrifice for heteroepitaxial growth of zinc-catecholate frameworks(Zn3(HHTP)2).Benefiting from amplification effect of in-situ formed heterojunctions,promoted interfacial charge transfer is achieved,which allows for fabricating broadband photodetectors.Combined with high porosity for gas adsorption,the heteroepitaxial catecholate framework further enables its use as highly selective ppb-level triethylamine sensors.This work provides a promising strategy for heteroepitaxial growth of catecholate frameworks on organo-substrates and opens new applications in wearable sensor platform based on comfortable biofibers.展开更多
Sustainable light energy from ambient environment has attracted particular attention to meet the evergrowing need of small-scale electronics.The modulation of intercorrelated thermal and electronic transport is one of...Sustainable light energy from ambient environment has attracted particular attention to meet the evergrowing need of small-scale electronics.The modulation of intercorrelated thermal and electronic transport is one of the crucial aspects for reliable photothermoelectric electronics.Herein,a defectpromoted photothermoelectric effect is demonstrated in densely aligned ZnO nanorod array with rich lattice defects.The defect-rich ZnO device delivers high electrical conductivity and large Seebeck coefficient to enable significant improvement of photothermoelectric energy conversion and self-powered photodetection.The position sensitivity reaches approximately 0.19 mV mm^(-1),and the temperature gradient induced electric field makes up for the suppression in the photothermoelectric process.The synergism between intrinsic defects and extra temperature field plays an important role in promoting the photothermoelectric properties of dense ZnO nanorod array.This study is interesting for interpreting the thermo-phototronic phenomena as well as demonstrating the possibility of defect engineering and phonon engineering to enable highly efficient light energy scavenging and self-powered photodetection.展开更多
Designing efficient non-noble metal catalysts with good oxygen reduction activity is highly desirable but challenging.Herein,we demonstrate the synthesis of Fe-based carbon materials with multi active sites of Fe–Nx,...Designing efficient non-noble metal catalysts with good oxygen reduction activity is highly desirable but challenging.Herein,we demonstrate the synthesis of Fe-based carbon materials with multi active sites of Fe–Nx,Fe_(3)O_(4) and Fe_(2)C for oxygen reduction through facile pyrolysis of a Fe–porphyrin conjugated microporous polymer.The nanofiber structure of the polymer is retained with in situ Fe and N heteroatom doping and Fe_(3)O_(4)/Fe_(2)C composite nanocrystals enchased in the walls of carbon fibers.Synergism between the N-doped carbon nanofibers and the in situ formed active sites of Fe–Nx,Fe_(2)C and Fe_(3)O_(4) facilitates the electrocatalytic performance of the as-synthesized catalysts.The catalyst obtained from 800℃ pyrolysis exhibits prominent oxygen reduction catalytic performance in 0.1 M KOH with an onset potential of 0.91 V,a half-wave potential of 0.81 V,and a small Tafel slope of 74 mV dec^(−1).Its limiting current density of−5.3 mA cm^(−2),excellent durability and resistance to methanol surpass the commercial 20% Pt/C under identical conditions.Thus,this work may provide a guideline for the design and synthesis of multi active nonprecious metal electrocatalysts for future fuel–cell applications.展开更多
基金supported by Key Project of NSFC (51790171, 51761145111, 51735005)NSFC for Excellent Young Scholars (11722219)
文摘The purpose of this paper is to present a shape preserving topology optimization method to prevent the adverse effects of the mechanical deformation on the Radar Cross Section(RCS).The optimization will suppress the variation of RCS on the perfect conductor surface by structural design.On the one hand,the physical optics method is utilized to calculate the structural RCS,which is based on the surface displacement field obtained from the finite element analysis of the structure.The corresponding design sensitivities of topology optimization are derived analytically and solved by the adjoint method.On the other hand,the RCS variation and mechanical performance are taken into account simultaneously by extending a standard compliance-based topology optimization model.Two optimization formulations are discussed in an illustrative example,where the influences of upper limits of the compliance and the RCS variation are considered.Two more examples are further tested to show the ability and validity of the proposed optimization method.
基金supported by the National Natural Science Foundation of China(No.51973099)Taishan Scholar Program of Shandong Province(No.tsqn201812055)+1 种基金Qingdao Science and Technology Plan Key Research and Development Special Project(No.21-1-2-17-xx)State Key Laboratory of Bio-Fibers and Eco-Textiles(Qingdao University)(Nos.ZKT04 and GZRC202007).
文摘Traditional triethylamine(TEA)sensors suffer from the drawback of serious cross-sensitivity due to the low charge-transfer ability of gas-sensing materials.Herein,an advanced anti-interference TEA sensor is designed by utilizing interfacial energy barriers of hierarchical Bi_(2)O_(3)/WO_(3) composite.Benefiting from abundant slit-like pores,desirable defect features,and amplification effect of heterojunctions,the sensor based on Bi_(2)O_(3)/WO_(3) composite with 40%Bi_(2)O_(3)(0.4-Bi_(2)O_(3)/WO_(3))demonstrates remarkable performance in terms of faster response/recovery time(1.7-fold/1.2-fold),higher response(2.1-fold),and lower power consumption(30℃-decrement)as compared with the pristine WO_(3) sensor.Furthermore,the composite sensor exhibits long-term stability,reproducibility,and negligible response towards interfering molecules,indicating the promising potential of Bi_(2)O_(3)/WO_(3) heterojunctions in anti-interference detection of low-concentration TEA in real applications.This work not only offers a rational solution to design advanced gas sensors by tuning the interfacial energy barriers of heterojunctions,but also provides a fundamental understanding of hierarchical Bi_(2)O_(3) structures in the gas-sensing field.
基金This work was supported by the National Natural Science Foundation of China(No.51973099)Taishan Scholar Program of Shandong Province(Nos.tsqn201812055 and tspd20181208)the State Key Laboratory of Bio-Fibers and Eco-Textiles(Qingdao University)(Nos.ZKT04 and GZRC202007).
文摘Integrating functional nanomaterials on nonplanar organisms has emerged as a rising technology,while significant mismatch would cause interface failure and poor durability.Herein,we demonstrate a facile strategy to assemble crystalline catecholate frameworks with honeycomb lattice on seaweed-derived polysaccharide microfibers,which is expected to form biomimetic connections and maintain durable stability.By physiological coagulation,well-aligned ZnO nanoarrays are tightly attached on alginate fibers,which is fractionally adopted as sacrifice for heteroepitaxial growth of zinc-catecholate frameworks(Zn3(HHTP)2).Benefiting from amplification effect of in-situ formed heterojunctions,promoted interfacial charge transfer is achieved,which allows for fabricating broadband photodetectors.Combined with high porosity for gas adsorption,the heteroepitaxial catecholate framework further enables its use as highly selective ppb-level triethylamine sensors.This work provides a promising strategy for heteroepitaxial growth of catecholate frameworks on organo-substrates and opens new applications in wearable sensor platform based on comfortable biofibers.
基金This work was supported by the National Natural Science Foundation of China(Nos.51973099,21761029)Taishan Scholar Program of Shandong Province(No.tsqn201812055)+3 种基金First Division Alar Science and Technology Plan Project in Xinjiang Corps(2019GJJ04)the State Key Laboratory of Bio-Fibers and Eco-Textiles(Qingdao University)(Nos.ZKT04,GZRC202007)the Dean Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(No.2017K005)Training Program for Outstanding Young Teachers in Xinjiang Corps,and the Engineering Laboratory of Chemical Resources Utilization in South Xinjiang of Xinjiang Production and Construction Corps(CRUZD2003).
文摘Sustainable light energy from ambient environment has attracted particular attention to meet the evergrowing need of small-scale electronics.The modulation of intercorrelated thermal and electronic transport is one of the crucial aspects for reliable photothermoelectric electronics.Herein,a defectpromoted photothermoelectric effect is demonstrated in densely aligned ZnO nanorod array with rich lattice defects.The defect-rich ZnO device delivers high electrical conductivity and large Seebeck coefficient to enable significant improvement of photothermoelectric energy conversion and self-powered photodetection.The position sensitivity reaches approximately 0.19 mV mm^(-1),and the temperature gradient induced electric field makes up for the suppression in the photothermoelectric process.The synergism between intrinsic defects and extra temperature field plays an important role in promoting the photothermoelectric properties of dense ZnO nanorod array.This study is interesting for interpreting the thermo-phototronic phenomena as well as demonstrating the possibility of defect engineering and phonon engineering to enable highly efficient light energy scavenging and self-powered photodetection.
基金supported by the National Natural Science Foundation of China(Grant No.21571187,21501198 and 21601205)the Taishan Scholar Foundation(ts201511019)the Fundamental Research Funds for the Central Universities(18CX02047A and 18CX07001A).
文摘Designing efficient non-noble metal catalysts with good oxygen reduction activity is highly desirable but challenging.Herein,we demonstrate the synthesis of Fe-based carbon materials with multi active sites of Fe–Nx,Fe_(3)O_(4) and Fe_(2)C for oxygen reduction through facile pyrolysis of a Fe–porphyrin conjugated microporous polymer.The nanofiber structure of the polymer is retained with in situ Fe and N heteroatom doping and Fe_(3)O_(4)/Fe_(2)C composite nanocrystals enchased in the walls of carbon fibers.Synergism between the N-doped carbon nanofibers and the in situ formed active sites of Fe–Nx,Fe_(2)C and Fe_(3)O_(4) facilitates the electrocatalytic performance of the as-synthesized catalysts.The catalyst obtained from 800℃ pyrolysis exhibits prominent oxygen reduction catalytic performance in 0.1 M KOH with an onset potential of 0.91 V,a half-wave potential of 0.81 V,and a small Tafel slope of 74 mV dec^(−1).Its limiting current density of−5.3 mA cm^(−2),excellent durability and resistance to methanol surpass the commercial 20% Pt/C under identical conditions.Thus,this work may provide a guideline for the design and synthesis of multi active nonprecious metal electrocatalysts for future fuel–cell applications.
