The new-generation electronic components require a balance between electromagnetic interference shielding efficiency and open structure factors such as ventilation and heat dissipation.In addition,realizing the tunabl...The new-generation electronic components require a balance between electromagnetic interference shielding efficiency and open structure factors such as ventilation and heat dissipation.In addition,realizing the tunable shielding of porous shields over a wide range of wavelengths is even more challenging.In this study,the well-prepared thermoplastic polyurethane/carbon nanotubes composites were used to fabricate the novel periodic porous flexible metamaterials using fused deposition modeling 3D printing.Particularly,the investigation focuses on optimization of pore geometry,size,dislocation configuration and material thickness,thus establishing a clear correlation between structural parameters and shielding property.Both experimental and simulation results have validated the superior shielding performance of hexagon derived honeycomb structure over other designs,and proposed the failure shielding size(D_(f)≈λ/8-λ/5)and critical inclined angle(θf≈43°-48°),which could be used as new benchmarks for tunable electromagnetic shielding.In addition,the proper regulation of the material thickness could remarkably enhance the maximum shielding capability(85-95 dB)and absorption coefficient A(over 0.83).The final innovative design of the porous shielding box also exhibits good shielding effectiveness across a broad frequency range(over 2.4 GHz),opening up novel pathways for individualized and diversified shielding solutions.展开更多
It is a prospective strategy to produce sustainable energy by photocatalytic overall water splitting(POWS).This work aims to develop a simple method for integrating a donor-acceptor system into polymeric car-bon nitri...It is a prospective strategy to produce sustainable energy by photocatalytic overall water splitting(POWS).This work aims to develop a simple method for integrating a donor-acceptor system into polymeric car-bon nitride(PCN)structure,which could accelerate the charge separation significantly.In the as-prepared photocatalyst(COCNT),carbon and oxygen were successfully incorporated into the framework of PCN,and the chemical environment of C and O was well probed by X-ray absorption near-edge structure(XANES)and X-ray photoelectron spectroscopy(XPS).It showed that the C-containing and O-containing segments of COCNT played the role of a donor,while the heptazine part played the role of an acceptor.In addition,Density-functional-theory(DFT)calculations confirmed the spatial split of the highest occupied molec-ular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)for promoting charge separation.Impressively,COCNT could efficiently split pure water to generate hydrogen and oxygen.And,the photo-catalytic hydrogen evolution rate over COCNT(1550.9μmol g^(-1)h^(-1))is about 17-fold higher than that of PCN.Finally,we proposed a possible photocatalytic mechanism to explain the above results.展开更多
The title polymeric complex [Cu(C_4H_2O_4)(C_(10)H_8N_2)]_n·2nH_2O wasprepared and its crystal structure was determined by X-ray diffraction methods. The crystal belongsto space group P2_1/c with cell dimensions ...The title polymeric complex [Cu(C_4H_2O_4)(C_(10)H_8N_2)]_n·2nH_2O wasprepared and its crystal structure was determined by X-ray diffraction methods. The crystal belongsto space group P2_1/c with cell dimensions of a = 1.0104(1), b = 1.9952(2), c = 0.7357(2) nm, β=98.38(2)° and Z = 4. The complex forms zig-zag chains along crystallographic axis c via Cu―O(car-boxyl) bond in the apical direction. Each repeated unit consists of a square pyramidal Cu( Ⅱ)centre with one maleate dianion and one 2, 2′-bipyridine forming a basal plane. Adjacent chainslink to each other by H-bonding between carboxyl groups and crystalline water. The distance of0.3482 run between parallel bipyridine rings shows a π- π stacking interaction. The title complexwas also characterized by IR, UV and ESR spectra.展开更多
The single crystals of the title compound were obtained from a reaction of MnCO3, benzenetetracarboxylic acid (H4BTC) and imidazole in an aqueous solution. The crystal of Mn(II) complex (C28H34Mn2N12O124H2O, Mr = 912....The single crystals of the title compound were obtained from a reaction of MnCO3, benzenetetracarboxylic acid (H4BTC) and imidazole in an aqueous solution. The crystal of Mn(II) complex (C28H34Mn2N12O124H2O, Mr = 912.62) belongs to tricli nic, space group P?with a = 10.036(1), b = 10.650(1), c = 11.102(1) , a = 114.72(2), b = 95.75(1), g = 108.46(2)o, V = 984.2(2) 3, Z = 1, Dc = 1.540 g/cm3, F(000) = 472, m(MoKa) = 0.726 mm-1, R = 0.0409 and wR = 0.1166 for 3909 observed reflections (I > 2s(I)). The crystal consists of the polymeric Mn(II) complex anions and discrete Mn(II) complex cations, both with normal octahedral coordination geometry. Each BTC bridges two Mn(II) atoms to form the anionic polymeric chain, and the cations distribute be- tween the chains and link them through both classic and weak CH…O H-bonding.展开更多
Thermal regeneration ofhypercrosslinked polymeric adsorbent （HPA） was performed at 67℃. Experiments were carried out using a multimode microwave oven operating at 2450 MHz and a thermostatic water bath so as to com...Thermal regeneration ofhypercrosslinked polymeric adsorbent （HPA） was performed at 67℃. Experiments were carried out using a multimode microwave oven operating at 2450 MHz and a thermostatic water bath so as to compare the effect of the different heating mechanisms on the regeneration efficiency of the HPA saturated with nitrophenols. The temperature rise action of the heterogeneous regeneration system under microwave irradiation was described. Additionally, a complete structure and chemical characterization of the regenerated HPA was also carried out in order to study the influence of the subsequent regeneration cycles on the structure and the adsorption capacities of the adsorbents. Structure characterization of the regenerated HPA was accomplished by means of the analysis of FTIR spectra.展开更多
Four bismuth complexes, (H2En)[Bi2(cit)2(H2O)4/3]·(H2O)x (1), (H2En)3[Bi2(cit)2Cl4]·(H2O)x (2), (HPy)2[Bi2(cit)2(H2O)8/5]·(H2O)x (3) and (H2En)[Bi2(cit)2](H2O)x (4) [cit = citrate4-; En = ethylenediamin...Four bismuth complexes, (H2En)[Bi2(cit)2(H2O)4/3]·(H2O)x (1), (H2En)3[Bi2(cit)2Cl4]·(H2O)x (2), (HPy)2[Bi2(cit)2(H2O)8/5]·(H2O)x (3) and (H2En)[Bi2(cit)2](H2O)x (4) [cit = citrate4-; En = ethylenediamine; Py = pyridine] have been synthesized and crystallized. The crystal structures reveal that the basic building blocks in all of these complexes are bismuth citrate dimeric units which combine to form polymeric architectures. The embedded protonated ethylenediamine and pyridine moieties in the polymeric frameworks have been identified by X-ray crystallography and solid-state cross polarization/magic angle spinning (CP/MAS) 13C NMR. Based on the framework of complex 1, a structural model of a clinically used antiulcer drug, ranitidine bismuth citrate (RBC) was generated. The behavior of the protonated amine-bismuth citrate complexes in acidic aqueous solution has been studied by electrospray ionization-mass spectrometry (ESI-MS).展开更多
Polymeric surfactants are amongst the most widespread of all polymers. In nature, proteins and polysaccharidescause self organization as a result of this surfactancy; in industry, polymeric surfactants play key roles ...Polymeric surfactants are amongst the most widespread of all polymers. In nature, proteins and polysaccharidescause self organization as a result of this surfactancy; in industry, polymeric surfactants play key roles in the food, explosivesand surface coatings sectors. The generation of useful nano- and micro-structures in films and emulsions as a result ofpolymer amphiphilicity and the application of mechanical stress is discussed. The use of X-ray and neutron small anglescattering and reflectivity to measure these structures and their dynamic properties will be described. New results on linear and dendritic polymer surfactants are presented.展开更多
基金supported by the National Key R&D Program of China(2023YFB4603504)the International Science&Technology Innovation Cooperation Project of Sichuan Province(2024YFHZ0232)+2 种基金the International Science&Technology Cooperation Project of Chengdu(2021-GH03-00009-HZ)the Program for Featured Directions of Engineering Multi-disciplines of Sichuan University(2020SCUNG203)the Program of Innovative Research Team for Young Scientists of Sichuan Province(22CXTD0019).
文摘The new-generation electronic components require a balance between electromagnetic interference shielding efficiency and open structure factors such as ventilation and heat dissipation.In addition,realizing the tunable shielding of porous shields over a wide range of wavelengths is even more challenging.In this study,the well-prepared thermoplastic polyurethane/carbon nanotubes composites were used to fabricate the novel periodic porous flexible metamaterials using fused deposition modeling 3D printing.Particularly,the investigation focuses on optimization of pore geometry,size,dislocation configuration and material thickness,thus establishing a clear correlation between structural parameters and shielding property.Both experimental and simulation results have validated the superior shielding performance of hexagon derived honeycomb structure over other designs,and proposed the failure shielding size(D_(f)≈λ/8-λ/5)and critical inclined angle(θf≈43°-48°),which could be used as new benchmarks for tunable electromagnetic shielding.In addition,the proper regulation of the material thickness could remarkably enhance the maximum shielding capability(85-95 dB)and absorption coefficient A(over 0.83).The final innovative design of the porous shielding box also exhibits good shielding effectiveness across a broad frequency range(over 2.4 GHz),opening up novel pathways for individualized and diversified shielding solutions.
基金supported by the National Natural Science Foundation of China(Nos.21703097 and 21972172)South-ern University of Science and Technology(SUSTech)start fund through the Shenzhen Peacock Talent program,the Shenzhen Ba-sic Research Fund project(No.JCYJ20150507170334573)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06N532).
文摘It is a prospective strategy to produce sustainable energy by photocatalytic overall water splitting(POWS).This work aims to develop a simple method for integrating a donor-acceptor system into polymeric car-bon nitride(PCN)structure,which could accelerate the charge separation significantly.In the as-prepared photocatalyst(COCNT),carbon and oxygen were successfully incorporated into the framework of PCN,and the chemical environment of C and O was well probed by X-ray absorption near-edge structure(XANES)and X-ray photoelectron spectroscopy(XPS).It showed that the C-containing and O-containing segments of COCNT played the role of a donor,while the heptazine part played the role of an acceptor.In addition,Density-functional-theory(DFT)calculations confirmed the spatial split of the highest occupied molec-ular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)for promoting charge separation.Impressively,COCNT could efficiently split pure water to generate hydrogen and oxygen.And,the photo-catalytic hydrogen evolution rate over COCNT(1550.9μmol g^(-1)h^(-1))is about 17-fold higher than that of PCN.Finally,we proposed a possible photocatalytic mechanism to explain the above results.
文摘The title polymeric complex [Cu(C_4H_2O_4)(C_(10)H_8N_2)]_n·2nH_2O wasprepared and its crystal structure was determined by X-ray diffraction methods. The crystal belongsto space group P2_1/c with cell dimensions of a = 1.0104(1), b = 1.9952(2), c = 0.7357(2) nm, β=98.38(2)° and Z = 4. The complex forms zig-zag chains along crystallographic axis c via Cu―O(car-boxyl) bond in the apical direction. Each repeated unit consists of a square pyramidal Cu( Ⅱ)centre with one maleate dianion and one 2, 2′-bipyridine forming a basal plane. Adjacent chainslink to each other by H-bonding between carboxyl groups and crystalline water. The distance of0.3482 run between parallel bipyridine rings shows a π- π stacking interaction. The title complexwas also characterized by IR, UV and ESR spectra.
文摘The single crystals of the title compound were obtained from a reaction of MnCO3, benzenetetracarboxylic acid (H4BTC) and imidazole in an aqueous solution. The crystal of Mn(II) complex (C28H34Mn2N12O124H2O, Mr = 912.62) belongs to tricli nic, space group P?with a = 10.036(1), b = 10.650(1), c = 11.102(1) , a = 114.72(2), b = 95.75(1), g = 108.46(2)o, V = 984.2(2) 3, Z = 1, Dc = 1.540 g/cm3, F(000) = 472, m(MoKa) = 0.726 mm-1, R = 0.0409 and wR = 0.1166 for 3909 observed reflections (I > 2s(I)). The crystal consists of the polymeric Mn(II) complex anions and discrete Mn(II) complex cations, both with normal octahedral coordination geometry. Each BTC bridges two Mn(II) atoms to form the anionic polymeric chain, and the cations distribute be- tween the chains and link them through both classic and weak CH…O H-bonding.
文摘Thermal regeneration ofhypercrosslinked polymeric adsorbent （HPA） was performed at 67℃. Experiments were carried out using a multimode microwave oven operating at 2450 MHz and a thermostatic water bath so as to compare the effect of the different heating mechanisms on the regeneration efficiency of the HPA saturated with nitrophenols. The temperature rise action of the heterogeneous regeneration system under microwave irradiation was described. Additionally, a complete structure and chemical characterization of the regenerated HPA was also carried out in order to study the influence of the subsequent regeneration cycles on the structure and the adsorption capacities of the adsorbents. Structure characterization of the regenerated HPA was accomplished by means of the analysis of FTIR spectra.
基金supported by the Research Grants Council of Hong Kong (HKU 703808P,HKU 704909P,HKU 107C and HKU 75209)the National Natural Science Foundation of China and Livzon Pharmaceutical Ltd
文摘Four bismuth complexes, (H2En)[Bi2(cit)2(H2O)4/3]·(H2O)x (1), (H2En)3[Bi2(cit)2Cl4]·(H2O)x (2), (HPy)2[Bi2(cit)2(H2O)8/5]·(H2O)x (3) and (H2En)[Bi2(cit)2](H2O)x (4) [cit = citrate4-; En = ethylenediamine; Py = pyridine] have been synthesized and crystallized. The crystal structures reveal that the basic building blocks in all of these complexes are bismuth citrate dimeric units which combine to form polymeric architectures. The embedded protonated ethylenediamine and pyridine moieties in the polymeric frameworks have been identified by X-ray crystallography and solid-state cross polarization/magic angle spinning (CP/MAS) 13C NMR. Based on the framework of complex 1, a structural model of a clinically used antiulcer drug, ranitidine bismuth citrate (RBC) was generated. The behavior of the protonated amine-bismuth citrate complexes in acidic aqueous solution has been studied by electrospray ionization-mass spectrometry (ESI-MS).
文摘Polymeric surfactants are amongst the most widespread of all polymers. In nature, proteins and polysaccharidescause self organization as a result of this surfactancy; in industry, polymeric surfactants play key roles in the food, explosivesand surface coatings sectors. The generation of useful nano- and micro-structures in films and emulsions as a result ofpolymer amphiphilicity and the application of mechanical stress is discussed. The use of X-ray and neutron small anglescattering and reflectivity to measure these structures and their dynamic properties will be described. New results on linear and dendritic polymer surfactants are presented.
