The park-level integrated energy system(PIES)is essential for achieving carbon neutrality by managing multi-energy supply and demand while enhancing renewable energy integration.However,current carbon trading mechanis...The park-level integrated energy system(PIES)is essential for achieving carbon neutrality by managing multi-energy supply and demand while enhancing renewable energy integration.However,current carbon trading mechanisms lack sufficient incentives for emission reductions,and traditional optimization algorithms often face challenges with convergence and local optima in complex PIES scheduling.To address these issues,this paper introduces a low-carbon dispatch strategy that combines a reward-penalty tiered carbon trading model with P2G-CCS integration,hydrogen utilization,and the Secretary Bird Optimization Algorithm(SBOA).Key innovations include:(1)A dynamic reward-penalty carbon trading mechanism with coefficients(μ=0.2,λ=0.15),which reduces carbon trading costs by 47.2%(from$694.06 to$366.32)compared to traditional tiered models,incentivizing voluntary emission reductions.(2)The integration of P2G-CCS coupling,which lowers natural gas consumption by 41.9%(from$4117.20 to$2389.23)and enhances CO_(2) recycling efficiency,addressing the limitations of standalone P2G or CCS technologies.(3)TheSBOA algorithm,which outperforms traditionalmethods(e.g.,PSO,GWO)in convergence speed and global search capability,avoiding local optima and achieving 24.39%faster convergence on CEC2005 benchmark functions.(4)A four-energy PIES framework incorporating electricity,heat,gas,and hydrogen,where hydrogen fuel cells and CHP systems improve demand response flexibility,reducing gas-related emissions by 42.1%and generating$13.14 in demand response revenue.Case studies across five scenarios demonstrate the strategy’s effectiveness:total operational costs decrease by 14.7%(from$7354.64 to$6272.59),carbon emissions drop by 49.9%(from 5294.94 to 2653.39kg),andrenewable energyutilizationincreases by24.39%(from4.82%to8.17%).These results affirmthemodel’s ability to reconcile economic and environmental goals,providing a scalable approach for low-carbon transitions in industrial parks.展开更多
Light-driven CO_(2) reduction reaction(CO_(2)RR)to value-added ethylene(C2H4)holds significant promise for addressing energy and environmental challenges.While the high energy barriers for*CO intermediates hydrogenati...Light-driven CO_(2) reduction reaction(CO_(2)RR)to value-added ethylene(C2H4)holds significant promise for addressing energy and environmental challenges.While the high energy barriers for*CO intermediates hydrogenation and C–C coupling limit the C_(2)H_(4)generation.Herein,CuxP/g-C_(3)N_(4) heterojunction prepared by an in-situ phosphating technique,achieved collaborative photocatalytic CO_(2) and H2O,producing CO and C_(2)H_(4)as the main products.Notably,the selectivity of C_(2)H_(4)produced by CuxP/g-C_(3)N_(4) attained to 64.25%,which was 9.85 times that of CuxP(6.52%).Detailed time-resolution photoluminescence spectra,femtosecond transient absorption spectroscopy tests and density functional theory(DFT)calculation validate the ultra-fast interfacial electron transfer mechanism in CuxP/g-C_(3)N_(4) heterojunction.Successive*H on P sites caused by adsorbed H2O splitting with moderate hydrogenation ability enables the multi-step hydrogenation during CO_(2)RR process over CuxP/g-C_(3)N_(4).With the aid of mediated asymmetric Cu and P dual sites by g-C_(3)N_(4) nanosheet,the produced*CHO shows an energetically favorable for C–C coupling.The coupling formed*CHOCHO further accepts photoexcited efficient e–and*H to deeply produce C_(2)H_(4)according to the C^(2+)intermediates,which has been detected by in-situ diffuse reflectance infrared Fourier transform spectroscopy and interpreted by DFT calculation.The novel insight mechanism offers an essential understanding for the development of CuxP-based heterojunctions for photocatalytic CO_(2) to C^(2+)value-added fuels.展开更多
（MnFe）2（P, Si）-type compounds are, to date, one of the best candidates for magnetic refrigeration and energy conversion applications due to the combination of giant magnetocaloric effect （MCE）, tunable working t...（MnFe）2（P, Si）-type compounds are, to date, one of the best candidates for magnetic refrigeration and energy conversion applications due to the combination of giant magnetocaloric effect （MCE）, tunable working temperature range and low material cost. The giant MCE in the （Mn, Fe）2（P, Si）-type compounds originates from strong mag- netoelastic coupling, where the lattice degrees of freedom and spin degrees of freedom are efficiently coupled. The tunability of the phase transition, in terms of the critical temperature and the character of the phase transition, is essentially attributed to the changes in the magnetoelastic coupling in the （Mn, Fe）2（P, Si）-type compounds. In this review, not only the fundamentals of the magnetoelastic coupling but also the related practical aspects such as magnetocaloric performance, hysteresis issue and mechanical stability are discussed for the （Mn, Fe）2（P, Si）- type compounds. Additionally, some future fundamental studies on the MCE as well as possible ways of solving the hysteresis and fracture issues are proposed.展开更多
A series of Na-W-Mn-Zr/SiO_(2)catalysts promoted by different contents of S or/and P were prepared and their catalytic performance for oxidative coupling of methane was investigated to clarify the effect of S and P on...A series of Na-W-Mn-Zr/SiO_(2)catalysts promoted by different contents of S or/and P were prepared and their catalytic performance for oxidative coupling of methane was investigated to clarify the effect of S and P on the Na-W-Mn-Zr/SiO_(2)catalyst.The catalysts were characterized by X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).From the characterization results,it is found that the addition of S and P to the Na-W-Mn-ZffSiO_(2)catalyst helps the formation of active phases,such asα-cristobalite,Na2WO4,ZrO_(2),and Na2SO4.Moreover,the addition of S and P increases the concentration of surface-active oxygen species by improving the migration of active components from the bulk phase to the surface of the catalyst.According to the activity test,impressive methane conversion and C2 hydrocarbons yield were obtained at a low temperature of 1023 K over the six-component Na-W-Mn-Zr-S-P/SiO_(2)catalyst,which contained 2 wt%S and 0.4 wt%P simultaneously.The deactivation of Na-W-Mn-Zr-S-P/SiO_(2)was due to the loss of surface active components.展开更多
在碳达峰碳中和的政策方针背景下,北方地区的冬季由于需要供热,使得热电联产机组(combined heat and power,CHP)强迫出力,限制了新能源的消纳与碳减排的能力。利用碳捕集与封存(carbon capture and storage,CCS)技术将热电联产机组产生...在碳达峰碳中和的政策方针背景下,北方地区的冬季由于需要供热,使得热电联产机组(combined heat and power,CHP)强迫出力,限制了新能源的消纳与碳减排的能力。利用碳捕集与封存(carbon capture and storage,CCS)技术将热电联产机组产生的CO_(2)捕捉并封存,将新能源发电通过电转气(power to gas,P2G)产生氢能并与捕集到的CO_(2)反应生成CH_(4),热电联产的燃气轮机使用合成的CH_(4)并掺入一定比例的H_(2)进行燃烧,循环使用CO_(2),减少碳排放并增加收益,进一步提高虚拟电厂参与电力市场的经济性与低碳性,促进新能源消纳,并保障北方冬季的供热量。建立了考虑P2G及碳捕集的热电联产虚拟电厂的数学模型,并通过MATLAB调用CPLEX求解器进行求解,仿真结果验证了所建模型的有效性。展开更多
Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the devel...Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather challenging.Herein,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea production.Our results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic properties.Interestingly,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side reactions.The outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active sites.Our findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.展开更多
Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship betw...Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.展开更多
在“双碳”背景下,为推进园区级综合能源系统(integrated energy systems,IES)建设、提升清洁能源消纳能力、降低园区碳排放,以综合能源系统运行总成本最小为目标函数,系统安全和机组出力为约束条件,引入电转气与碳捕获系统耦合设备,综...在“双碳”背景下,为推进园区级综合能源系统(integrated energy systems,IES)建设、提升清洁能源消纳能力、降低园区碳排放,以综合能源系统运行总成本最小为目标函数,系统安全和机组出力为约束条件,引入电转气与碳捕获系统耦合设备,综合考虑了阶梯式碳交易和碳封存成本,建立了含氢储能的综合能源系统低碳调度模型。最后以某园区为算例,运用CPLEX求解器对所提模型进行求解,算例结果表明所建模型能够有效提高系统的经济性与低碳性,提高园区新能源消纳能力,减少弃风弃光等成本,进一步降低园区碳排放并减少经济运行成本,提高综合能源系统运行灵活性。展开更多
The objective of this study was to prepare a new photocatalyst with high activities for degradation of organic pollutants.Coupled ZrO_(2)/ZnO photocatalyst was prepared with a simple precipitation method with cheap ra...The objective of this study was to prepare a new photocatalyst with high activities for degradation of organic pollutants.Coupled ZrO_(2)/ZnO photocatalyst was prepared with a simple precipitation method with cheap raw materials zinc acetate and zirconium oxychloride,and was character-ized by X-ray diffraction(XRD)and transmission electron microscopy(TEM).Reactive brilliant red X-3B was used as a model compound to investigate the photocatalytic activity of synthesized catalysts in water under 254 nm UV irradia-tion.Results show that the optimal calcination temperature and coupling molar ratio of Zr were 350°C and 2.5%,respec-tively.At the calcination temperature of 350°C,ZrO_(2) was dispersed on the surface of hexagonal ZnO in the form of amorphous clusters.The particle size of ZrO_(2)/ZnO decreased with the decrease of calcination temperature and the increase of Zr coupling amount.ZrO_(2)/ZnO has better photocatalytic activity for degradation of reactive brilliant red(RBR)X-3B than pure ZnO and P25-TiO_(2).展开更多
This paper describes the synthesis and free radical polymerization of 2,5 bis(4′ alkyloxyphenyl)styrene(M n ) for mesogen jacketed liquid crystal polymers(MJLCPs), where p terphenyl subsituted by alkoxy groups at bot...This paper describes the synthesis and free radical polymerization of 2,5 bis(4′ alkyloxyphenyl)styrene(M n ) for mesogen jacketed liquid crystal polymers(MJLCPs), where p terphenyl subsituted by alkoxy groups at both ends was used as mesogenic unit. Because of the absence of the polar linkage groups, such as —COO— or —CONH— as employed in the previous reported MJLCPs, M n is believed to be polymerized easily by both free radical polymerization and ionic polymerization. The chemical structure of M n was proved by 1H NMR, mass spectrometry and elementary analysis. Their phase transition and liquid crystallinity were characterized by DSC and POM. Although M 1, M 2, M 3 and M 4 exhibited monotropic nematic mesophase, M 5 displayed enantiotropic nematic mesophase presumably because of its decreased melting transition temperature. All monomers were easily polymerized to moderately high molecular weight polymers. At elevated temperature above T g, poly[2,5 bis(4′ alkoxyphenyl)styrene] showed a very stable mesophase. The formed birefrigence did not disappear until thermal decomposition started. Compared to other MJLCPs, the polymers reported here have much higher thermal stability. [WT5HZ]展开更多
基金funded by State Grid Beijing Electric Power Company Technology Project,grant number 520210230004.
文摘The park-level integrated energy system(PIES)is essential for achieving carbon neutrality by managing multi-energy supply and demand while enhancing renewable energy integration.However,current carbon trading mechanisms lack sufficient incentives for emission reductions,and traditional optimization algorithms often face challenges with convergence and local optima in complex PIES scheduling.To address these issues,this paper introduces a low-carbon dispatch strategy that combines a reward-penalty tiered carbon trading model with P2G-CCS integration,hydrogen utilization,and the Secretary Bird Optimization Algorithm(SBOA).Key innovations include:(1)A dynamic reward-penalty carbon trading mechanism with coefficients(μ=0.2,λ=0.15),which reduces carbon trading costs by 47.2%(from$694.06 to$366.32)compared to traditional tiered models,incentivizing voluntary emission reductions.(2)The integration of P2G-CCS coupling,which lowers natural gas consumption by 41.9%(from$4117.20 to$2389.23)and enhances CO_(2) recycling efficiency,addressing the limitations of standalone P2G or CCS technologies.(3)TheSBOA algorithm,which outperforms traditionalmethods(e.g.,PSO,GWO)in convergence speed and global search capability,avoiding local optima and achieving 24.39%faster convergence on CEC2005 benchmark functions.(4)A four-energy PIES framework incorporating electricity,heat,gas,and hydrogen,where hydrogen fuel cells and CHP systems improve demand response flexibility,reducing gas-related emissions by 42.1%and generating$13.14 in demand response revenue.Case studies across five scenarios demonstrate the strategy’s effectiveness:total operational costs decrease by 14.7%(from$7354.64 to$6272.59),carbon emissions drop by 49.9%(from 5294.94 to 2653.39kg),andrenewable energyutilizationincreases by24.39%(from4.82%to8.17%).These results affirmthemodel’s ability to reconcile economic and environmental goals,providing a scalable approach for low-carbon transitions in industrial parks.
文摘Light-driven CO_(2) reduction reaction(CO_(2)RR)to value-added ethylene(C2H4)holds significant promise for addressing energy and environmental challenges.While the high energy barriers for*CO intermediates hydrogenation and C–C coupling limit the C_(2)H_(4)generation.Herein,CuxP/g-C_(3)N_(4) heterojunction prepared by an in-situ phosphating technique,achieved collaborative photocatalytic CO_(2) and H2O,producing CO and C_(2)H_(4)as the main products.Notably,the selectivity of C_(2)H_(4)produced by CuxP/g-C_(3)N_(4) attained to 64.25%,which was 9.85 times that of CuxP(6.52%).Detailed time-resolution photoluminescence spectra,femtosecond transient absorption spectroscopy tests and density functional theory(DFT)calculation validate the ultra-fast interfacial electron transfer mechanism in CuxP/g-C_(3)N_(4) heterojunction.Successive*H on P sites caused by adsorbed H2O splitting with moderate hydrogenation ability enables the multi-step hydrogenation during CO_(2)RR process over CuxP/g-C_(3)N_(4).With the aid of mediated asymmetric Cu and P dual sites by g-C_(3)N_(4) nanosheet,the produced*CHO shows an energetically favorable for C–C coupling.The coupling formed*CHOCHO further accepts photoexcited efficient e–and*H to deeply produce C_(2)H_(4)according to the C^(2+)intermediates,which has been detected by in-situ diffuse reflectance infrared Fourier transform spectroscopy and interpreted by DFT calculation.The novel insight mechanism offers an essential understanding for the development of CuxP-based heterojunctions for photocatalytic CO_(2) to C^(2+)value-added fuels.
基金financially supported by the Key Research & Development Program of Jiangsu Province(No.BE2017102)
文摘（MnFe）2（P, Si）-type compounds are, to date, one of the best candidates for magnetic refrigeration and energy conversion applications due to the combination of giant magnetocaloric effect （MCE）, tunable working temperature range and low material cost. The giant MCE in the （Mn, Fe）2（P, Si）-type compounds originates from strong mag- netoelastic coupling, where the lattice degrees of freedom and spin degrees of freedom are efficiently coupled. The tunability of the phase transition, in terms of the critical temperature and the character of the phase transition, is essentially attributed to the changes in the magnetoelastic coupling in the （Mn, Fe）2（P, Si）-type compounds. In this review, not only the fundamentals of the magnetoelastic coupling but also the related practical aspects such as magnetocaloric performance, hysteresis issue and mechanical stability are discussed for the （Mn, Fe）2（P, Si）- type compounds. Additionally, some future fundamental studies on the MCE as well as possible ways of solving the hysteresis and fracture issues are proposed.
基金supported by the National Natural Science Foundation of China(20676116)
文摘A series of Na-W-Mn-Zr/SiO_(2)catalysts promoted by different contents of S or/and P were prepared and their catalytic performance for oxidative coupling of methane was investigated to clarify the effect of S and P on the Na-W-Mn-Zr/SiO_(2)catalyst.The catalysts were characterized by X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).From the characterization results,it is found that the addition of S and P to the Na-W-Mn-ZffSiO_(2)catalyst helps the formation of active phases,such asα-cristobalite,Na2WO4,ZrO_(2),and Na2SO4.Moreover,the addition of S and P increases the concentration of surface-active oxygen species by improving the migration of active components from the bulk phase to the surface of the catalyst.According to the activity test,impressive methane conversion and C2 hydrocarbons yield were obtained at a low temperature of 1023 K over the six-component Na-W-Mn-Zr-S-P/SiO_(2)catalyst,which contained 2 wt%S and 0.4 wt%P simultaneously.The deactivation of Na-W-Mn-Zr-S-P/SiO_(2)was due to the loss of surface active components.
文摘在碳达峰碳中和的政策方针背景下,北方地区的冬季由于需要供热,使得热电联产机组(combined heat and power,CHP)强迫出力,限制了新能源的消纳与碳减排的能力。利用碳捕集与封存(carbon capture and storage,CCS)技术将热电联产机组产生的CO_(2)捕捉并封存,将新能源发电通过电转气(power to gas,P2G)产生氢能并与捕集到的CO_(2)反应生成CH_(4),热电联产的燃气轮机使用合成的CH_(4)并掺入一定比例的H_(2)进行燃烧,循环使用CO_(2),减少碳排放并增加收益,进一步提高虚拟电厂参与电力市场的经济性与低碳性,促进新能源消纳,并保障北方冬季的供热量。建立了考虑P2G及碳捕集的热电联产虚拟电厂的数学模型,并通过MATLAB调用CPLEX求解器进行求解,仿真结果验证了所建模型的有效性。
基金financially supported in China by Natural Science Funds for Distinguished Young Scholars of Heilongjiang Province(No.JC2018004)Natural Science Foundation of Heilongjiang Province of China(No.TD2020B001)in the USA by NSF-CREST Center for Innovation,Research,and Education in Environmental Nanotechnology(CIRE2N)(No.HRD-1736093)
文摘Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather challenging.Herein,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea production.Our results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic properties.Interestingly,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side reactions.The outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active sites.Our findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.
基金supported by the National Natural Science Foundation of China(22265021)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.
文摘在“双碳”背景下,为推进园区级综合能源系统(integrated energy systems,IES)建设、提升清洁能源消纳能力、降低园区碳排放,以综合能源系统运行总成本最小为目标函数,系统安全和机组出力为约束条件,引入电转气与碳捕获系统耦合设备,综合考虑了阶梯式碳交易和碳封存成本,建立了含氢储能的综合能源系统低碳调度模型。最后以某园区为算例,运用CPLEX求解器对所提模型进行求解,算例结果表明所建模型能够有效提高系统的经济性与低碳性,提高园区新能源消纳能力,减少弃风弃光等成本,进一步降低园区碳排放并减少经济运行成本,提高综合能源系统运行灵活性。
文摘The objective of this study was to prepare a new photocatalyst with high activities for degradation of organic pollutants.Coupled ZrO_(2)/ZnO photocatalyst was prepared with a simple precipitation method with cheap raw materials zinc acetate and zirconium oxychloride,and was character-ized by X-ray diffraction(XRD)and transmission electron microscopy(TEM).Reactive brilliant red X-3B was used as a model compound to investigate the photocatalytic activity of synthesized catalysts in water under 254 nm UV irradia-tion.Results show that the optimal calcination temperature and coupling molar ratio of Zr were 350°C and 2.5%,respec-tively.At the calcination temperature of 350°C,ZrO_(2) was dispersed on the surface of hexagonal ZnO in the form of amorphous clusters.The particle size of ZrO_(2)/ZnO decreased with the decrease of calcination temperature and the increase of Zr coupling amount.ZrO_(2)/ZnO has better photocatalytic activity for degradation of reactive brilliant red(RBR)X-3B than pure ZnO and P25-TiO_(2).
文摘This paper describes the synthesis and free radical polymerization of 2,5 bis(4′ alkyloxyphenyl)styrene(M n ) for mesogen jacketed liquid crystal polymers(MJLCPs), where p terphenyl subsituted by alkoxy groups at both ends was used as mesogenic unit. Because of the absence of the polar linkage groups, such as —COO— or —CONH— as employed in the previous reported MJLCPs, M n is believed to be polymerized easily by both free radical polymerization and ionic polymerization. The chemical structure of M n was proved by 1H NMR, mass spectrometry and elementary analysis. Their phase transition and liquid crystallinity were characterized by DSC and POM. Although M 1, M 2, M 3 and M 4 exhibited monotropic nematic mesophase, M 5 displayed enantiotropic nematic mesophase presumably because of its decreased melting transition temperature. All monomers were easily polymerized to moderately high molecular weight polymers. At elevated temperature above T g, poly[2,5 bis(4′ alkoxyphenyl)styrene] showed a very stable mesophase. The formed birefrigence did not disappear until thermal decomposition started. Compared to other MJLCPs, the polymers reported here have much higher thermal stability. [WT5HZ]
