Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban tran...Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban transportation carbon emission reduction.Since the whole life cycle of urban rail transit carbon emission measurement involves a wide range of aspects,a systematic framework model is required for analysis.This research reviews the existing studies on carbon emission of urban rail transit.First,the characteristics of urban rail transit carbon emission were determined and the complexity of carbon emission measurement was analyzed.Then,the urban rail transit carbon emission measurement models were compared and analyzed in terms of the selection of research boundaries,the types of greenhouse gas(GHG)emissions calculation,and the accuracy of the measurement.Following that,an intelligent station was introduced to analyze the practical application of digital collaboration technology and energy-saving and carbon-reducing system platforms for rail transit.Finally,the urgent problems and future research directions at this stage were discussed.This research presents the necessity of establishing a dynamic carbon emission factor library and the important development trend of system integration of carbon emission measurement and digital system technology.展开更多
This paper primarily discusses the main circuit of single-phase inverter circuits.It begins by introducing the research context and the significance of the subject,then discusses the topology of grid-connected single-...This paper primarily discusses the main circuit of single-phase inverter circuits.It begins by introducing the research context and the significance of the subject,then discusses the topology of grid-connected single-phase inverter circuits,continues by discussing the control strategy for grid-connected single-phase inverter circuits,realizes a sinusoidal pulse width modulation(SPWM)signal generation circuit and an inverse control algorithm program,and finally ensures good output waveform and fast dynamic response.In view of the hysteresis feature of the grid voltage’s synchronous signal sampling circuit,the acquisition function in digital signal processing(DSP)control chips is applied,and the reasons for the hysteresis phenomenon are thoroughly investigated.The reliability of the SPWM control algorithm is revealed through the results.展开更多
The isoindolinone and biaryl scaffolds are prevalent in natural products and drug molecules,which have showed broad and interesting biological activities.The efficient construction of such hybridized molecules and bio...The isoindolinone and biaryl scaffolds are prevalent in natural products and drug molecules,which have showed broad and interesting biological activities.The efficient construction of such hybridized molecules and biological evaluation are of great interest to medicinal chemistry community.In this communication,we report an efficient BrΦnsted acid-promoted C(sp^3)-H functionalization approach that enables the rapid construction of biologically important isoindolinone/[1,2,4]triazolo[1,5-a]pyrimidine hybrids from 5-methyl-7-(2,4,6-trimethoxyphenyl)-[1,2,4]triazolo[1,5-a]pyrimidine,2-formylbenzoic acid and various anilines.The title compounds were generated in high to excellent yields(up to 96%)regardless of the electronic nature and steric effects of the substituents.In this reaction,an isoindolinone scaffold,one C-C single bond,and two C-N bonds were formed simultaneously with high atom economy.In this work,we have envisioned that the methyl group linked to the electron-deficient Nheterocycles could be used as a new synthetic handle for late-state diversification and may have broad applications in the field of organic and medicinal chemistry.Besides,the title compounds have exhibited promising activity against the SKP2-CKS1 interaction.展开更多
Fibrosis is a common problem in soft tissue regeneration,often caused by the differentiation of fibroblasts into myofibro-blasts.Because of the nanoscale topology that regulates the mechanical transduction of cells,na...Fibrosis is a common problem in soft tissue regeneration,often caused by the differentiation of fibroblasts into myofibro-blasts.Because of the nanoscale topology that regulates the mechanical transduction of cells,nanofibers or nanoparticles are commonly used to modulate fibroblast differentiation.However,the strength of nanofibers is insufficient,and the physi-ological toxicity of nanoparticles still remains to be verified.In this study,self-induced crystallization was used to construct nano-protrusions on the random and aligned polycaprolactone microfibers to regulate the behavior of fibroblasts.The results revealed that the mechanical properties of microfibers with a nanoscale topology were improved.Immunofluorescence staining manifested that nano-protrusions impeded the activation of integrins and vinculins,thereby inhibiting the nuclear transfer of Yes-associated protein,resulting in a decrease in the expression ofα-smooth muscle actin.Nanoscale topology of microfibers hampered the activation of the Rho/ROCK signalling pathway.In general,we used a simple process to con-struct a fibrous scaffold with a micro-nano multilevel structure.This structure can hinder the transformation of fibroblasts into myofibroblasts on both random and aligned fibers,which is expected to prevent fibrosis.展开更多
基金supported by Beijing Natural Science Foundation(J210001)Natural Science Foundation of Hebei Province(E2021210142)Tianjin Natural Science Foundation(21JCZXJC00160).
文摘Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban transportation carbon emission reduction.Since the whole life cycle of urban rail transit carbon emission measurement involves a wide range of aspects,a systematic framework model is required for analysis.This research reviews the existing studies on carbon emission of urban rail transit.First,the characteristics of urban rail transit carbon emission were determined and the complexity of carbon emission measurement was analyzed.Then,the urban rail transit carbon emission measurement models were compared and analyzed in terms of the selection of research boundaries,the types of greenhouse gas(GHG)emissions calculation,and the accuracy of the measurement.Following that,an intelligent station was introduced to analyze the practical application of digital collaboration technology and energy-saving and carbon-reducing system platforms for rail transit.Finally,the urgent problems and future research directions at this stage were discussed.This research presents the necessity of establishing a dynamic carbon emission factor library and the important development trend of system integration of carbon emission measurement and digital system technology.
文摘This paper primarily discusses the main circuit of single-phase inverter circuits.It begins by introducing the research context and the significance of the subject,then discusses the topology of grid-connected single-phase inverter circuits,continues by discussing the control strategy for grid-connected single-phase inverter circuits,realizes a sinusoidal pulse width modulation(SPWM)signal generation circuit and an inverse control algorithm program,and finally ensures good output waveform and fast dynamic response.In view of the hysteresis feature of the grid voltage’s synchronous signal sampling circuit,the acquisition function in digital signal processing(DSP)control chips is applied,and the reasons for the hysteresis phenomenon are thoroughly investigated.The reliability of the SPWM control algorithm is revealed through the results.
基金supported by the National Natural Science Foundation of China(Nos.81773562 and 81703326)China Postdoctoral Science Foundation(Nos.2018M630840 and 2019T120641)Scientific Program of Henan Province(No.182102310123)。
文摘The isoindolinone and biaryl scaffolds are prevalent in natural products and drug molecules,which have showed broad and interesting biological activities.The efficient construction of such hybridized molecules and biological evaluation are of great interest to medicinal chemistry community.In this communication,we report an efficient BrΦnsted acid-promoted C(sp^3)-H functionalization approach that enables the rapid construction of biologically important isoindolinone/[1,2,4]triazolo[1,5-a]pyrimidine hybrids from 5-methyl-7-(2,4,6-trimethoxyphenyl)-[1,2,4]triazolo[1,5-a]pyrimidine,2-formylbenzoic acid and various anilines.The title compounds were generated in high to excellent yields(up to 96%)regardless of the electronic nature and steric effects of the substituents.In this reaction,an isoindolinone scaffold,one C-C single bond,and two C-N bonds were formed simultaneously with high atom economy.In this work,we have envisioned that the methyl group linked to the electron-deficient Nheterocycles could be used as a new synthetic handle for late-state diversification and may have broad applications in the field of organic and medicinal chemistry.Besides,the title compounds have exhibited promising activity against the SKP2-CKS1 interaction.
基金Supported by Shanghai Sailing Program(Grant No.20YF1400800)Shanghai Science and Technology Development Fund(21S31900700)111 Project 2.0(Grant no.BP0719035).
文摘Fibrosis is a common problem in soft tissue regeneration,often caused by the differentiation of fibroblasts into myofibro-blasts.Because of the nanoscale topology that regulates the mechanical transduction of cells,nanofibers or nanoparticles are commonly used to modulate fibroblast differentiation.However,the strength of nanofibers is insufficient,and the physi-ological toxicity of nanoparticles still remains to be verified.In this study,self-induced crystallization was used to construct nano-protrusions on the random and aligned polycaprolactone microfibers to regulate the behavior of fibroblasts.The results revealed that the mechanical properties of microfibers with a nanoscale topology were improved.Immunofluorescence staining manifested that nano-protrusions impeded the activation of integrins and vinculins,thereby inhibiting the nuclear transfer of Yes-associated protein,resulting in a decrease in the expression ofα-smooth muscle actin.Nanoscale topology of microfibers hampered the activation of the Rho/ROCK signalling pathway.In general,we used a simple process to con-struct a fibrous scaffold with a micro-nano multilevel structure.This structure can hinder the transformation of fibroblasts into myofibroblasts on both random and aligned fibers,which is expected to prevent fibrosis.
