The literature is full of claims regarding the consumption of polyphenol or polyamine-rich foods that offer some protection from developing cardiovascular disease(CVD). This is achieved by preventing cardiac hypertrop...The literature is full of claims regarding the consumption of polyphenol or polyamine-rich foods that offer some protection from developing cardiovascular disease(CVD). This is achieved by preventing cardiac hypertrophy and protecting blood vessels through improving the function of endothelium. However, do these interventions work in the aged human hearts? Cardiac aging is accompanied by an increase in left ventricular hypertrophy, along with diastolic and systolic dysfunction. It also confers significant cardiovascular risks for both sexes. The incidence and prevalence of CVD increase sharply at an earlier age in men than women. Furthermore, the patterns of heart failure differ between sexes, as do the lifetime risk factors. Do caloric restriction(CR)-mimetics, rich in polyphenol or polyamine, delay or reverse cardiac aging equally in both men and women? This review will discuss three areas:(1) mechanisms underlying age-related cardiac remodeling;(2) gender-related differences and potential mechanisms underlying diminished cardiac response in older men and women;(3) we select a few polyphenol or polyamine rich compounds as the CRmimetics, such as resveratrol, quercetin, curcumin, epigallocatechin gallate and spermidine, due to their capability to extend health-span and induce autophagy. We outline their abilities and issues on retarding aging in animal hearts and preventing CVD in humans. We discuss the confounding factors that should be considered for developing therapeutic strategies against cardiac aging in humans.展开更多
Nitrogen oxides are one of the most significant pollution sources during coal combustion. This experimental study was conducted in a 15 kWth lab-scale pressurized fluidized bed (inner diameter = 81-100 mm, H = 2100 mm...Nitrogen oxides are one of the most significant pollution sources during coal combustion. This experimental study was conducted in a 15 kWth lab-scale pressurized fluidized bed (inner diameter = 81-100 mm, H = 2100 mm) firing with bituminous coals. The effects of operating parameters, including bed temperature (800℃-900℃), operating pressure (0.1-0.4 MPa), excess air level (16%-30%) and flow pattern on NOX and N2O emissions were systematically studied during the tests. During each test the interaction effects of all the operating parameters were properly controlled. The results show that most operating parameters have an opposite effect on NOX and N2O emissions, and the N2O emissions mainly depend on the bed temperature. Increasing the operating pressure can significantly suppress the fuel-N conversion to NOX but enhance its conversion to N2O. With the rise of the excess air level and fluidization number, NOX emissions grow distinctly while N2O emissions remain almost unchanged. Total nitrogen oxide emissions increase with the bed temperature while decrease with the operating pressure.展开更多
This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration...This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm estimates.The Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise impact.The successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed vigor.Finally,a model for seed vigor classifi-cation of Q.variabili s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was developed.The results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection methods.The combination SG second derivative-LS-SVM provided the best classification model for Q.variabilis seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.展开更多
Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic a...Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic air flow,and gas discharge is an effective way to achieve this.A nanosecond pulsed discharge experimental system under supersonic conditions was established,and a pin-to-plate nanosecond pulsed discharge experiment in Mach 2 air flow was performed to verify that the proposed method produced uniform and stable plasma under supersonic conditions.The results show that the discharge under supersonic conditions was stable overall,but uniformity was not as good as that under static conditions.Increasing the number of pins improved discharge uniformity,but reduced discharge intensity and hence plasma density.Under multi-pin conditions at 1000Hz,the discharge was almost completely corona discharge,with the main current component being the displacement current,which was smaller than that under static conditions.展开更多
[Objectives]The quality of Lycium ruthenicum Murr.from different producing areas was studied.[Methods]The content of proanthocyanidins(UV spectrophotometry),water-soluble vitamins(VB 2,VB 6,VB 12,Vc,niacinamide,and fo...[Objectives]The quality of Lycium ruthenicum Murr.from different producing areas was studied.[Methods]The content of proanthocyanidins(UV spectrophotometry),water-soluble vitamins(VB 2,VB 6,VB 12,Vc,niacinamide,and folic acid)),fat-soluble vitamins(VD,and VK 1)(high performance liquid chromatography),and trace elements Cu,Zn,and Fe(flame atomic absorption method)in L.ruthenicum from Ejin Banner of Inner Mongolia,Nuomuhong of Qinghai and Korla of Xinjiang were measured.[Results]The content of proanthocyanidins,VB 2,nicotinamide and VB 12 in L.ruthenicum from Ejin Banner was higher,and the content of Vc,VB 6,Cu,Zn,VD and VK 1 in L.ruthenicum from Nuomuhong was higher,while the content of folic acid and Fe in L.ruthenicum from Korla was higher.The proanthocyanidin content of L.ruthenicum from Ejin Banner was the highest,so it is an ideal plant for extracting proanthocyanidins.[Conclusions]This study provides a theoretical basis for the research,development and utilization of L.ruthenicum from Nuomuhong,Ejin Banner and Korla.展开更多
In this study,civil gas energy accidents reported by the China Gas Network and related organizations from 2012 to 2021 were collected,and a comprehensive multidimensional correlation analysis was conducted considering...In this study,civil gas energy accidents reported by the China Gas Network and related organizations from 2012 to 2021 were collected,and a comprehensive multidimensional correlation analysis was conducted considering factors such as accident timing,geography,causes,and casualties.The results identified July and August,Mondays and Sundays,and the morning,mid-day,and evening cooking times as the high-incidence months,days,and times for gas accidents,respectively.Gas accidents were found to occur more frequently in eastern coastal areas,provincial capitals,and larger cities,while residential and construction sites were identified as high-risk areas for gas accidents.Explosions were the most prevalent type of gas accident,followed by leaks,fires,and poisoning.Third-party construction and valve issues were identified as the primary factors contributing to gas leakage,whereas cooking was identified as the most common ignition source.An analysis of the Pearson correlation coefficient indicated a significant correlation among the gas accident factors.Moreover,a time-series prediction model was developed to forecast gas accidents in China,with the results demonstrating fluctuating gas accidents.This study proposes targeted preventive measures in terms of publicity,education,equipment,and facilities to provide scientific support to government units to improve civil gas energy security measures.展开更多
Lappaconitine(LA),a natural compound with a novel C18-diterpenoid alkaloid skeleton,displayed extensive biological profile.Recent research on LA is focused mainly on its anti-tumor and analgesic effects,and therefore ...Lappaconitine(LA),a natural compound with a novel C18-diterpenoid alkaloid skeleton,displayed extensive biological profile.Recent research on LA is focused mainly on its anti-tumor and analgesic effects,and therefore we aimed to investigate its anti-inflammatory potential.A series of novel LA derivatives with various substituents on the 20-N position was designed and synthesized.In the initial screening of LA derivatives against NO production,all the target compounds,except compound E2,exhibited excellent inhibitory ability relative to that of LA.Particularly,compound A4 exhibited the most potent inhibition with IC50 of 12.91 mmol/L.The elementary structureeactivity relationships(SARs)of NO inhibitory activity indicated that replacement of the benzene ring with an electron donating group could improve the anti-inflammatory efficacy.Furthermore,compound A4 shows an anti-inflammatory mechanism by inhibiting NO,PGE2,and TNF-a generation via the suppression of NF-kB and MAPK signaling pathways.Notably,compound A4 could exert a significant therapeutic effect on LPS-induced acute lung injury(ALI)in vivo.Based on the above research,we further investigated the preliminary pharmacokinetic property of A4 in rats.Therefore,compound A4 could be a promising candidate for the development of anti-inflammatory agents in the future.展开更多
Delivery of proteins to the plasma membrane occurs via secretion,which requires tethering,docking,priming,and fusion of vesicles.In yeast and mammalian cells,an evolutionarily conserved RAB GTPase activation cascade f...Delivery of proteins to the plasma membrane occurs via secretion,which requires tethering,docking,priming,and fusion of vesicles.In yeast and mammalian cells,an evolutionarily conserved RAB GTPase activation cascade functions together with the exocyst and SNARE proteins to coordinate vesicle transport with fusion at the plasma membrane.However,it is unclear whether this is the case in plants.In this study,we show that the small GTPase RABA2a recruits and interacts with the VAMP721/722-SYP121-SNAP33 SNARE ternary complex for membrane fusion.Through immunoprecipitation coupled with mass spectrometry analysis followed by the validatation with a series of biochemical assays,we identified the SNARE proteins VAMP721 and SYP121 as the interactors and downstream effectors of RABA2a.Further expreiments showed that RABA2a interacts with all members of the SNARE complex in its GTP-bound form and modulates the assembly of the VAMP721/722-SYP121-SNAP33 SNARE ternary complex.Intriguingly,we did not observe the interaction of the exocyst subunits with either RABA2a or theSNARE proteins in several different experiments.Neither RABA2a inactivation affects the subcellular localization or assembly of the exocystnor the exocyst subunit mutant exo84b shows the disrupted RABA2a-SNARE association or SNARE assembly,suggesting that the RABA2a-SNARE-and exocyst-mediated secretory pathways are largely independent.Consistently,our live imaging experiments reveal that the two sets of proteins follow non-overlapping trafficking routes,and genetic and cell biologyanalyses indicate that the two pathways select different cargos.Finally,we demonstrate that the plant-specific RABA2a-SNARE pathway is essential for the maintenance of potassium homeostasis in Arabisopsis seedlings.Collectively,our findings imply that higher plants might have generated different endomembrane sorting pathways during evolution and may enable the highly conserved endomembrane proteins to participate in plant-specific trafficking mechanisms for adaptation to the changing environment.展开更多
Due to the technology limitation and inferior deNO_(x) efficiency of urea selective catalytic reduction (SCR) catalysts at low temperatures, passive NO_(x) adsorber (PNA) for decrease of NO_(x), CO and hydrocarbons (H...Due to the technology limitation and inferior deNO_(x) efficiency of urea selective catalytic reduction (SCR) catalysts at low temperatures, passive NO_(x) adsorber (PNA) for decrease of NO_(x), CO and hydrocarbons (HCs) during “cold start” of vehicles was proposed to meet the further tighten NO_(x) emission regulations in future. Among them, Pd modified zeolite PNA materials have received more attention because of their excellent NO_(x) storage capacity, anti-poisoning and hydrothermal stability and since Pd/zeolite PNA was proposed, a variety of advanced characterization methods have been applied to investigate its adsorption behavior and structure-performance relationship. The comprehension of the active sites and adsorption chemistry of Pd/zeolite PNA was also significantly improved. However, there are few reviews that systematically summarize the recent progress and application challenges in atomic-level understanding of this material. In this review, we summarized the latest research progress of Pd/zeolite PNA, including active adsorption sites, adsorption mechanism, material physicochemical properties, preparation methods, storage and release performance and structure-performance relationships. In addition, the deactivation challenges faced by Pd/zeolite PNA in practical applications, such as chemical poisoning, high temperature hydrothermal aging deactivation, etc., were also discussed at the micro-level, and some possible effective countermeasures are given. Besides, some possible improvements and research hotspots were put forward, which could be helpful for designing and constructing more efficient PNA materials for meeting the ultra-low NO_(x) emission regulation in the future.展开更多
With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with ...With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application,due to their abundant and tailorable structure.Herein,[(CH_(3))_(3)S]_(2)SnCl_(6)・H_(2)O is synthesized as a host for dopant ions Bi^(3+)and Sb^(3+).The Sb^(3+)doped,or Bi^(3+)/Sb^(3+)co-doped,[(CH_(3))3S]_(2)SnCl_(6)・H_(2)O has a tunable optical emission spectrum by means of varying dopant ratio and excitation wavelength.As a result,we can achieve single-phase materials suitable for emission ranging from cold white light to warm white light.The intrinsic mechanism is examined in this work,to clarify the dopant effect on the optical properties.The high stability of title crystalline material,against water,oxygen and heat,makes it promising for further application.展开更多
基金supported by grants from the National Natural Science Foundation of China(81800245,81970228,82102306,81900779)the China Postdoctoral Science Foundation(2020M670030ZX)+1 种基金the Shaoguan Science and Technology Program(2019sn078)the Start-up Fund for RAPs under the Strategic Hiring Scheme(P0035913)。
文摘The literature is full of claims regarding the consumption of polyphenol or polyamine-rich foods that offer some protection from developing cardiovascular disease(CVD). This is achieved by preventing cardiac hypertrophy and protecting blood vessels through improving the function of endothelium. However, do these interventions work in the aged human hearts? Cardiac aging is accompanied by an increase in left ventricular hypertrophy, along with diastolic and systolic dysfunction. It also confers significant cardiovascular risks for both sexes. The incidence and prevalence of CVD increase sharply at an earlier age in men than women. Furthermore, the patterns of heart failure differ between sexes, as do the lifetime risk factors. Do caloric restriction(CR)-mimetics, rich in polyphenol or polyamine, delay or reverse cardiac aging equally in both men and women? This review will discuss three areas:(1) mechanisms underlying age-related cardiac remodeling;(2) gender-related differences and potential mechanisms underlying diminished cardiac response in older men and women;(3) we select a few polyphenol or polyamine rich compounds as the CRmimetics, such as resveratrol, quercetin, curcumin, epigallocatechin gallate and spermidine, due to their capability to extend health-span and induce autophagy. We outline their abilities and issues on retarding aging in animal hearts and preventing CVD in humans. We discuss the confounding factors that should be considered for developing therapeutic strategies against cardiac aging in humans.
基金Supported by the National Key R&D Program of China(2016YFB0600802)the National Natural Science Foundation of China(51736002)
文摘Nitrogen oxides are one of the most significant pollution sources during coal combustion. This experimental study was conducted in a 15 kWth lab-scale pressurized fluidized bed (inner diameter = 81-100 mm, H = 2100 mm) firing with bituminous coals. The effects of operating parameters, including bed temperature (800℃-900℃), operating pressure (0.1-0.4 MPa), excess air level (16%-30%) and flow pattern on NOX and N2O emissions were systematically studied during the tests. During each test the interaction effects of all the operating parameters were properly controlled. The results show that most operating parameters have an opposite effect on NOX and N2O emissions, and the N2O emissions mainly depend on the bed temperature. Increasing the operating pressure can significantly suppress the fuel-N conversion to NOX but enhance its conversion to N2O. With the rise of the excess air level and fluidization number, NOX emissions grow distinctly while N2O emissions remain almost unchanged. Total nitrogen oxide emissions increase with the bed temperature while decrease with the operating pressure.
基金funded by the National Natural Science Foundation of China(Grant No.31770769)the National Key Research and Development Program of China(No.2017YFC0504403)the Fundamental Research Funds for the Central Universities(No.2015ZCQ-GX-03).
文摘This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm estimates.The Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise impact.The successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed vigor.Finally,a model for seed vigor classifi-cation of Q.variabili s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was developed.The results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection methods.The combination SG second derivative-LS-SVM provided the best classification model for Q.variabilis seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.
基金National Natural Science Foundation of China (Nos. 11372352, 51776222)the China Postdoctoral Science Foundation (Nos. 2017T100772, 2016M590972).
文摘Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic air flow,and gas discharge is an effective way to achieve this.A nanosecond pulsed discharge experimental system under supersonic conditions was established,and a pin-to-plate nanosecond pulsed discharge experiment in Mach 2 air flow was performed to verify that the proposed method produced uniform and stable plasma under supersonic conditions.The results show that the discharge under supersonic conditions was stable overall,but uniformity was not as good as that under static conditions.Increasing the number of pins improved discharge uniformity,but reduced discharge intensity and hence plasma density.Under multi-pin conditions at 1000Hz,the discharge was almost completely corona discharge,with the main current component being the displacement current,which was smaller than that under static conditions.
基金Supported by Support Fund for Young Graduate Tutors(No.GAU-QNDS-201715)Sheng Tongsheng Innovation Fund(No.GSAU-STS-1736)+1 种基金Gansu Provincial Key Laboratory of Aridland Crop Science,Gansu Agricultural University(No.GSCS-2012-14)Study on Breeding and Propagation Techniques of Lycium ruthenicum Murr.(NLKY[2015]No.3)
文摘[Objectives]The quality of Lycium ruthenicum Murr.from different producing areas was studied.[Methods]The content of proanthocyanidins(UV spectrophotometry),water-soluble vitamins(VB 2,VB 6,VB 12,Vc,niacinamide,and folic acid)),fat-soluble vitamins(VD,and VK 1)(high performance liquid chromatography),and trace elements Cu,Zn,and Fe(flame atomic absorption method)in L.ruthenicum from Ejin Banner of Inner Mongolia,Nuomuhong of Qinghai and Korla of Xinjiang were measured.[Results]The content of proanthocyanidins,VB 2,nicotinamide and VB 12 in L.ruthenicum from Ejin Banner was higher,and the content of Vc,VB 6,Cu,Zn,VD and VK 1 in L.ruthenicum from Nuomuhong was higher,while the content of folic acid and Fe in L.ruthenicum from Korla was higher.The proanthocyanidin content of L.ruthenicum from Ejin Banner was the highest,so it is an ideal plant for extracting proanthocyanidins.[Conclusions]This study provides a theoretical basis for the research,development and utilization of L.ruthenicum from Nuomuhong,Ejin Banner and Korla.
基金The authors appreciate the financial support from the opening project of the State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)(No.KFJJ23-19 M)the Beijing Nova Program Interdisciplinary Cooperation Project(No.Z2111000021211)the opening project of Tianjin Key Laboratory of Fire Safety Technology(No.2023TKLFST06).
文摘In this study,civil gas energy accidents reported by the China Gas Network and related organizations from 2012 to 2021 were collected,and a comprehensive multidimensional correlation analysis was conducted considering factors such as accident timing,geography,causes,and casualties.The results identified July and August,Mondays and Sundays,and the morning,mid-day,and evening cooking times as the high-incidence months,days,and times for gas accidents,respectively.Gas accidents were found to occur more frequently in eastern coastal areas,provincial capitals,and larger cities,while residential and construction sites were identified as high-risk areas for gas accidents.Explosions were the most prevalent type of gas accident,followed by leaks,fires,and poisoning.Third-party construction and valve issues were identified as the primary factors contributing to gas leakage,whereas cooking was identified as the most common ignition source.An analysis of the Pearson correlation coefficient indicated a significant correlation among the gas accident factors.Moreover,a time-series prediction model was developed to forecast gas accidents in China,with the results demonstrating fluctuating gas accidents.This study proposes targeted preventive measures in terms of publicity,education,equipment,and facilities to provide scientific support to government units to improve civil gas energy security measures.
基金supported by the National Natural Science Foundation of China(No.21662036).
文摘Lappaconitine(LA),a natural compound with a novel C18-diterpenoid alkaloid skeleton,displayed extensive biological profile.Recent research on LA is focused mainly on its anti-tumor and analgesic effects,and therefore we aimed to investigate its anti-inflammatory potential.A series of novel LA derivatives with various substituents on the 20-N position was designed and synthesized.In the initial screening of LA derivatives against NO production,all the target compounds,except compound E2,exhibited excellent inhibitory ability relative to that of LA.Particularly,compound A4 exhibited the most potent inhibition with IC50 of 12.91 mmol/L.The elementary structureeactivity relationships(SARs)of NO inhibitory activity indicated that replacement of the benzene ring with an electron donating group could improve the anti-inflammatory efficacy.Furthermore,compound A4 shows an anti-inflammatory mechanism by inhibiting NO,PGE2,and TNF-a generation via the suppression of NF-kB and MAPK signaling pathways.Notably,compound A4 could exert a significant therapeutic effect on LPS-induced acute lung injury(ALI)in vivo.Based on the above research,we further investigated the preliminary pharmacokinetic property of A4 in rats.Therefore,compound A4 could be a promising candidate for the development of anti-inflammatory agents in the future.
基金This work was supported by the Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes(2019KSYS006)was also financially supported by grants from the Natural Science Foundation of China(31770306)+7 种基金the Natural Science Foundation of Guangdong Province(2020A1515010966)the Guangdong Innovation Research Team Fund(2016ZT06S172)the Shenzhen Sci-Tech Fund(KYTDPT20181011104005)Z.M.and Y.M.were supported financially by the Singapore Ministry of Education(MOE)Tier 1(RG32/20)and Tier 3(MOE2019-T3-1-012)X.Z.was supported financially by the National Science Foundation for Young Scientists of China(32000558)the China Postdoctoral Science Foundation(grant no.2019M660494)R.L.L.was supported financially by the Natural Science Foundation of China(31970182,31670182)the Fundamental Research Funds for the Central Universities(2019ZY29).
文摘Delivery of proteins to the plasma membrane occurs via secretion,which requires tethering,docking,priming,and fusion of vesicles.In yeast and mammalian cells,an evolutionarily conserved RAB GTPase activation cascade functions together with the exocyst and SNARE proteins to coordinate vesicle transport with fusion at the plasma membrane.However,it is unclear whether this is the case in plants.In this study,we show that the small GTPase RABA2a recruits and interacts with the VAMP721/722-SYP121-SNAP33 SNARE ternary complex for membrane fusion.Through immunoprecipitation coupled with mass spectrometry analysis followed by the validatation with a series of biochemical assays,we identified the SNARE proteins VAMP721 and SYP121 as the interactors and downstream effectors of RABA2a.Further expreiments showed that RABA2a interacts with all members of the SNARE complex in its GTP-bound form and modulates the assembly of the VAMP721/722-SYP121-SNAP33 SNARE ternary complex.Intriguingly,we did not observe the interaction of the exocyst subunits with either RABA2a or theSNARE proteins in several different experiments.Neither RABA2a inactivation affects the subcellular localization or assembly of the exocystnor the exocyst subunit mutant exo84b shows the disrupted RABA2a-SNARE association or SNARE assembly,suggesting that the RABA2a-SNARE-and exocyst-mediated secretory pathways are largely independent.Consistently,our live imaging experiments reveal that the two sets of proteins follow non-overlapping trafficking routes,and genetic and cell biologyanalyses indicate that the two pathways select different cargos.Finally,we demonstrate that the plant-specific RABA2a-SNARE pathway is essential for the maintenance of potassium homeostasis in Arabisopsis seedlings.Collectively,our findings imply that higher plants might have generated different endomembrane sorting pathways during evolution and may enable the highly conserved endomembrane proteins to participate in plant-specific trafficking mechanisms for adaptation to the changing environment.
基金financial support from the National Natural Science Foundation of China (No. 52000084)the China Postdoctoral Science Foundation (No. 2019M662630)National Engineering Laboratory for Mobile Source Emission Control Technology (No. NELMS2018A08)。
文摘Due to the technology limitation and inferior deNO_(x) efficiency of urea selective catalytic reduction (SCR) catalysts at low temperatures, passive NO_(x) adsorber (PNA) for decrease of NO_(x), CO and hydrocarbons (HCs) during “cold start” of vehicles was proposed to meet the further tighten NO_(x) emission regulations in future. Among them, Pd modified zeolite PNA materials have received more attention because of their excellent NO_(x) storage capacity, anti-poisoning and hydrothermal stability and since Pd/zeolite PNA was proposed, a variety of advanced characterization methods have been applied to investigate its adsorption behavior and structure-performance relationship. The comprehension of the active sites and adsorption chemistry of Pd/zeolite PNA was also significantly improved. However, there are few reviews that systematically summarize the recent progress and application challenges in atomic-level understanding of this material. In this review, we summarized the latest research progress of Pd/zeolite PNA, including active adsorption sites, adsorption mechanism, material physicochemical properties, preparation methods, storage and release performance and structure-performance relationships. In addition, the deactivation challenges faced by Pd/zeolite PNA in practical applications, such as chemical poisoning, high temperature hydrothermal aging deactivation, etc., were also discussed at the micro-level, and some possible effective countermeasures are given. Besides, some possible improvements and research hotspots were put forward, which could be helpful for designing and constructing more efficient PNA materials for meeting the ultra-low NO_(x) emission regulation in the future.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.22373014 and 22371043)the Natural Science Foundation of Fujian Province(No.2022J06019)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF009).
文摘With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application,due to their abundant and tailorable structure.Herein,[(CH_(3))_(3)S]_(2)SnCl_(6)・H_(2)O is synthesized as a host for dopant ions Bi^(3+)and Sb^(3+).The Sb^(3+)doped,or Bi^(3+)/Sb^(3+)co-doped,[(CH_(3))3S]_(2)SnCl_(6)・H_(2)O has a tunable optical emission spectrum by means of varying dopant ratio and excitation wavelength.As a result,we can achieve single-phase materials suitable for emission ranging from cold white light to warm white light.The intrinsic mechanism is examined in this work,to clarify the dopant effect on the optical properties.The high stability of title crystalline material,against water,oxygen and heat,makes it promising for further application.
