Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte s...Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ignored.Consequently,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)electrodes.The results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the adsorbate.This finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR activity.Additional support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine adsorption.We further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR activity.This study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.展开更多
Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturall...Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturally grown on Cu_(0.75)Ni_(0.25)(111) film and investigate the electronic structure by angle-resolved photoemission spectroscopy.Compared with other substrates,our TBG with a wafer scale is acquired with a shorter growth time.The Fermi velocity and energy gap of Dirac cones of TBG are comparable with those of a monolayer on Cu_(0.85)Ni_(0.15)(111).The signature of moré lattices has not been observed in either the low-energy electron diffraction patterns or the Fermi surface map within experimental resolution,possibly due to different Cu and Ni contents in the substrates enhancing the different couplings between the substrate and the first/second layers and hindering the formation of a quasiperiodic structure.展开更多
Monolithic textured perovskite/silicon tandem solar cells(TSCs)are expected to achieve maximum light capture at the lowest cost,potentially exhibiting the best power conversion efficiency.However,it is challenging to ...Monolithic textured perovskite/silicon tandem solar cells(TSCs)are expected to achieve maximum light capture at the lowest cost,potentially exhibiting the best power conversion efficiency.However,it is challenging to fabricate high-quality perovskite films and preferred crystal orientation on commercially textured silicon substrates with micrometersize pyramids.Here,we introduced a bulky organic molecule(4-fluorobenzylamine hydroiodide(F-PMAI))as a perovskite additive.It is found that F-PMAI can retard the crystallization process of perovskite film through hydrogen bond interaction between F^(−)and FA^(+)and reduce(111)facet surface energy due to enhanced adsorption energy of F-PMAI on the(111)facet.Besides,the bulky molecular is extruded to the bottom and top of perovskite film after crystal growth,which can passivate interface defects through strong interaction between F-PMA+and undercoordinated Pb^(2+)/I^(−).As a result,the additive facilitates the formation of large perovskite grains and(111)preferred orientation with a reduced trap-state density,thereby promoting charge carrier transportation,and enhancing device performance and stability.The perovskite/silicon TSCs achieved a champion efficiency of 30.05%based on a silicon thin film tunneling junction.In addition,the devices exhibit excellent longterm thermal and light stability without encapsulation.This work provides an effective strategy for achieving efficient and stable TSCs.展开更多
This work shows that despite a lattice mismatch of almost 20%, CdMnTe/CdTe/CdMnTe heterostructures grown directly on Si(111) have surprisingly good optical emission properties. The investigated structures were grown b...This work shows that despite a lattice mismatch of almost 20%, CdMnTe/CdTe/CdMnTe heterostructures grown directly on Si(111) have surprisingly good optical emission properties. The investigated structures were grown by molecular beam epitaxy and characterized by scanning transmission electron microscopy, macro-and micro-photoluminescence. Low temperature macro-photoluminescence experiments indicate three emission bands which depend on the CdTe layer thickness and have different confinement characteristics. Temperature measurements reveal that the lower energy emission band (at 1.48 eV)is associated to defects and bound exciton states, while the main emission at 1.61 eV has a weak 2D character and the higher energy one at 1.71 eV has a well-defined (zero-dimensional, 0D) 0D nature. Micro-photoluminescence measurements show the existence of sharp and strongly circularly polarized (up to 40%) emission lines which can be related to the presence of Mn in the heterostructure. This result opens the possibility of producing photon sources with the typical spin control of the diluted magnetic semiconductors using the low-cost silicon technology.展开更多
BACKGROUND As hepatic myelolipoma is rarely encountered,its radiological diagnosis using ultrasonography(US),computed tomography(CT),and magnetic resonance imaging(MRI)is challenging.Hepatic myelolipoma is similar to ...BACKGROUND As hepatic myelolipoma is rarely encountered,its radiological diagnosis using ultrasonography(US),computed tomography(CT),and magnetic resonance imaging(MRI)is challenging.Hepatic myelolipoma is similar to fat-contained hepatic lesions seen in hepatocellular carcinoma and angiomyolipoma.Therefore,further development of techniques to diagnose hepatic myelolipoma is warranted.CASE SUMMARY A 44-year-old obese man was found to have a hepatic lesion during his medical checkup.The lesion was 50 mm×57 mm in size and was detected in segment 8(S8)of the liver by US.The patient was diagnosed with hepatic lesion 20 years ago,but it was left unresolved.The patient had no symptoms,liver dysfunction,hepatitis virus antibody,or tumor marker elevation.Plain CT showed a welldefined lesion in S8 of the liver.The central and peripheral areas of the lesion primarily exhibited fat density and hypodensity,respectively.MRI revealed a capsule-like structure.Biopsy was performed to address the probability of hepatocellular carcinoma.The lesion was pathologically confirmed as a myelolipoma.Bone marrow scintigraphy performed using 111InCl3 revealed accumulation of the radiopharmaceutical in the soft tissue component,except in the fat-dominant part of the tumor,as well as in the surrounding liver parenchyma due to the presence of reticuloendothelial cells in the liver.CONCLUSION This is the first report on the diagnosis of hepatic myelolipoma using 111InCl3 scintigraphy.The effectiveness of bone marrow scintigraphy for diagnosing hepatic myelolipoma might be limited.As radiopharmaceuticals accumulate in both hematopoietic and reticuloendothelial cells,the accumulation of radiopharmaceuticals in the lesion is obscure.展开更多
基金supported by the National Natural Science Foundation of China(no.22372154,21972131).
文摘Despite substantial efforts in developing high-performance catalysts for the oxygen reduction reaction(ORR),the persistent challenge lies in the high onset overpotential of the ORR,and the effect of the elec-trolyte solution cannot be ignored.Consequently,we have systematically investigated the impact of adsorbate species and concentration,as well as solution pH,on the ORR activity on Pt(111)and Pt(poly)electrodes.The results all tend to establish a linear quantitative relationship between the onset potential for ORR and the adsorption equilibrium potential of the adsorbate.This finding indicates the decisive role of adsorbates in the onset potential for ORR,suggesting that the adsorption potential of adsorbates can serve as an intuitive criterion for ORR activity.Additional support for this conclusion is derived from experimental results obtained from the oxygen evolution reaction on Pt(poly)with different adsorbate species and from the hydrogen evolution reaction on Pt(111)with iodine adsorption.We further propose both an empirical equation for the onset potential for ORR and the concept of a potential-regulated adsor-bate shielding effect to elucidate the influence of adsorbates on ORR activity.This study provides new insights into the high onset overpotential of the ORR and offers potential strategies for predicting and enhancingORRactivity inthefuture.
基金Project supported by the National Key R&D Program of China (Grant Nos. 2022YFB3608000 and 2022YFA1204900)the National Natural Science Foundation of China (Grant Nos. 12222413 and 12074205)+2 种基金the Natural Science Foundation of Shanghai (Grant Nos. 23ZR1482200 and 22ZR1473300)the Natural Science Foundation of Zhejiang Province (Grant No. LQ21A040004)the funding of Ningbo University (Grant No. LJ2024003)。
文摘Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturally grown on Cu_(0.75)Ni_(0.25)(111) film and investigate the electronic structure by angle-resolved photoemission spectroscopy.Compared with other substrates,our TBG with a wafer scale is acquired with a shorter growth time.The Fermi velocity and energy gap of Dirac cones of TBG are comparable with those of a monolayer on Cu_(0.85)Ni_(0.15)(111).The signature of moré lattices has not been observed in either the low-energy electron diffraction patterns or the Fermi surface map within experimental resolution,possibly due to different Cu and Ni contents in the substrates enhancing the different couplings between the substrate and the first/second layers and hindering the formation of a quasiperiodic structure.
基金the financial support of National Key Research and Development Program of China(Grant No.2023YFB4202503)the Joint Funds of the National Natural Science Foundation of China(Grant No.U21A2072)+7 种基金Natural Science Foundation of China(Grant No.62274099)Natural Science Foundation of Tianjin(No.20JCQNJC02070)China Postdoctoral Science Foundation(No.2020T130317)the Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China(Grant No.B16027)Tianjin Science and Technology Project(Grant No.18ZXJMTG00220)Key R&D Program of Hebei Province(No.19214301D)provided by the Haihe Laboratory of Sustainable Chemical Transformationsthe Fundamental Research Funds for the Central Universities,Nankai University.
文摘Monolithic textured perovskite/silicon tandem solar cells(TSCs)are expected to achieve maximum light capture at the lowest cost,potentially exhibiting the best power conversion efficiency.However,it is challenging to fabricate high-quality perovskite films and preferred crystal orientation on commercially textured silicon substrates with micrometersize pyramids.Here,we introduced a bulky organic molecule(4-fluorobenzylamine hydroiodide(F-PMAI))as a perovskite additive.It is found that F-PMAI can retard the crystallization process of perovskite film through hydrogen bond interaction between F^(−)and FA^(+)and reduce(111)facet surface energy due to enhanced adsorption energy of F-PMAI on the(111)facet.Besides,the bulky molecular is extruded to the bottom and top of perovskite film after crystal growth,which can passivate interface defects through strong interaction between F-PMA+and undercoordinated Pb^(2+)/I^(−).As a result,the additive facilitates the formation of large perovskite grains and(111)preferred orientation with a reduced trap-state density,thereby promoting charge carrier transportation,and enhancing device performance and stability.The perovskite/silicon TSCs achieved a champion efficiency of 30.05%based on a silicon thin film tunneling junction.In addition,the devices exhibit excellent longterm thermal and light stability without encapsulation.This work provides an effective strategy for achieving efficient and stable TSCs.
基金the financial support by the Brazilian funding agencies CAPES, CNPq (306201/2022-4)FAPEMIG (APQ-00371-17, APQ-02500-22, APQ-00388-22, and RED00223-23)FAPESP (2021/06803-4)。
文摘This work shows that despite a lattice mismatch of almost 20%, CdMnTe/CdTe/CdMnTe heterostructures grown directly on Si(111) have surprisingly good optical emission properties. The investigated structures were grown by molecular beam epitaxy and characterized by scanning transmission electron microscopy, macro-and micro-photoluminescence. Low temperature macro-photoluminescence experiments indicate three emission bands which depend on the CdTe layer thickness and have different confinement characteristics. Temperature measurements reveal that the lower energy emission band (at 1.48 eV)is associated to defects and bound exciton states, while the main emission at 1.61 eV has a weak 2D character and the higher energy one at 1.71 eV has a well-defined (zero-dimensional, 0D) 0D nature. Micro-photoluminescence measurements show the existence of sharp and strongly circularly polarized (up to 40%) emission lines which can be related to the presence of Mn in the heterostructure. This result opens the possibility of producing photon sources with the typical spin control of the diluted magnetic semiconductors using the low-cost silicon technology.
文摘BACKGROUND As hepatic myelolipoma is rarely encountered,its radiological diagnosis using ultrasonography(US),computed tomography(CT),and magnetic resonance imaging(MRI)is challenging.Hepatic myelolipoma is similar to fat-contained hepatic lesions seen in hepatocellular carcinoma and angiomyolipoma.Therefore,further development of techniques to diagnose hepatic myelolipoma is warranted.CASE SUMMARY A 44-year-old obese man was found to have a hepatic lesion during his medical checkup.The lesion was 50 mm×57 mm in size and was detected in segment 8(S8)of the liver by US.The patient was diagnosed with hepatic lesion 20 years ago,but it was left unresolved.The patient had no symptoms,liver dysfunction,hepatitis virus antibody,or tumor marker elevation.Plain CT showed a welldefined lesion in S8 of the liver.The central and peripheral areas of the lesion primarily exhibited fat density and hypodensity,respectively.MRI revealed a capsule-like structure.Biopsy was performed to address the probability of hepatocellular carcinoma.The lesion was pathologically confirmed as a myelolipoma.Bone marrow scintigraphy performed using 111InCl3 revealed accumulation of the radiopharmaceutical in the soft tissue component,except in the fat-dominant part of the tumor,as well as in the surrounding liver parenchyma due to the presence of reticuloendothelial cells in the liver.CONCLUSION This is the first report on the diagnosis of hepatic myelolipoma using 111InCl3 scintigraphy.The effectiveness of bone marrow scintigraphy for diagnosing hepatic myelolipoma might be limited.As radiopharmaceuticals accumulate in both hematopoietic and reticuloendothelial cells,the accumulation of radiopharmaceuticals in the lesion is obscure.
