This paper is devoted to the study of semi-commutative harmonic analysis associated with Hermite semigroups. In the first part, we establish the noncommutative maximal inequalities for Bochner-Riesz means associated w...This paper is devoted to the study of semi-commutative harmonic analysis associated with Hermite semigroups. In the first part, we establish the noncommutative maximal inequalities for Bochner-Riesz means associated with Hermite operators and then obtain the corresponding pointwise convergence theorems. In particular, we develop a noncommutative version of Stein's theorem of Bochner-Riesz means for Hermite operators. In the second part, we investigate two noncommutative multiplier theorems. Our approach in this part relies on a noncommutative analog of the classical Littlewood-Paley-Stein theory associated with Hermite semigroups.展开更多
Carbon neutrality has been considered a new focus of countries for achieving the goal of the Paris Agreement.China has pledged to peak CO_(2) emissions before 2030 and achieve carbon neutrality before 2060,and a"...Carbon neutrality has been considered a new focus of countries for achieving the goal of the Paris Agreement.China has pledged to peak CO_(2) emissions before 2030 and achieve carbon neutrality before 2060,and a"1+N"policy framework has been built to guide the implementations.Scientific and technological innovation has been emphasized as one of the key strategies to establish an innovation system,strengthen research,and promote applications of green and low-carbon technologies[1].Despite numerous studies and policies on decarbonization technologies,studies focusing on technological development pathways for China’s carbon neutrality are needed[2].展开更多
Direct synthesis of dimethyl ether(DME)by CO2 hydrogenation has been investigated over three hybrid catalysts prepared by different methods:co-precipitation,sol-gel,and solid grinding to produce mixed Cu,ZnO,ZrO2 cata...Direct synthesis of dimethyl ether(DME)by CO2 hydrogenation has been investigated over three hybrid catalysts prepared by different methods:co-precipitation,sol-gel,and solid grinding to produce mixed Cu,ZnO,ZrO2 catalysts that were physically mixed with a commercial ferrierite(FER)zeolite.The catalysts were characterized by N2 physisorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),temperature programmed desorption of CO2(CO2-TPD),temperature programmed desorption of NH3(NH3-TPD),and temperature programmed H2 reduction(H2-TPR).The results demonstrate that smaller CuO and Cu crystallite sizes resulting in better dispersion of the active phases,higher surface area,and lower reduction temperature are all favorable for catalytic activity.The reaction mechanism has been studied using in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS).Methanol appears to be formed via the bidentate-formate(b-HCOO)species undergoing stepwise hydrogenation,while DME formation occurs from methanol dehydration and reaction of two surface methoxy groups.展开更多
基金supported by National Natural Science Foundation of China (Grant No. 12071355)National Research Foundation of Korea (Grant No. NRF-2022R1A2C1092320)Samsung Science and Technology Foundation (Grant No. SSTF-BA2002-01)。
文摘This paper is devoted to the study of semi-commutative harmonic analysis associated with Hermite semigroups. In the first part, we establish the noncommutative maximal inequalities for Bochner-Riesz means associated with Hermite operators and then obtain the corresponding pointwise convergence theorems. In particular, we develop a noncommutative version of Stein's theorem of Bochner-Riesz means for Hermite operators. In the second part, we investigate two noncommutative multiplier theorems. Our approach in this part relies on a noncommutative analog of the classical Littlewood-Paley-Stein theory associated with Hermite semigroups.
基金support on data research and technological deployment provided by the Administrative Centre for China’s Agenda 21,Ministry of Science and Technology of the People’s Republic of Chinathe funding provided by the National Natural Science Foundation of China(72140005 and 51621003)。
文摘Carbon neutrality has been considered a new focus of countries for achieving the goal of the Paris Agreement.China has pledged to peak CO_(2) emissions before 2030 and achieve carbon neutrality before 2060,and a"1+N"policy framework has been built to guide the implementations.Scientific and technological innovation has been emphasized as one of the key strategies to establish an innovation system,strengthen research,and promote applications of green and low-carbon technologies[1].Despite numerous studies and policies on decarbonization technologies,studies focusing on technological development pathways for China’s carbon neutrality are needed[2].
基金supported by the China Scholarship Council(No.201608140182)the University of Wyomingand State of Wyoming。
文摘Direct synthesis of dimethyl ether(DME)by CO2 hydrogenation has been investigated over three hybrid catalysts prepared by different methods:co-precipitation,sol-gel,and solid grinding to produce mixed Cu,ZnO,ZrO2 catalysts that were physically mixed with a commercial ferrierite(FER)zeolite.The catalysts were characterized by N2 physisorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),temperature programmed desorption of CO2(CO2-TPD),temperature programmed desorption of NH3(NH3-TPD),and temperature programmed H2 reduction(H2-TPR).The results demonstrate that smaller CuO and Cu crystallite sizes resulting in better dispersion of the active phases,higher surface area,and lower reduction temperature are all favorable for catalytic activity.The reaction mechanism has been studied using in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS).Methanol appears to be formed via the bidentate-formate(b-HCOO)species undergoing stepwise hydrogenation,while DME formation occurs from methanol dehydration and reaction of two surface methoxy groups.
