Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-...Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-reduction method. The electrochemical stability of Tin O2n-1 was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V(vs NHE) in 0.5 mol/L H2SO4 aqueous solution. The catalytic activity and stability of the Pt/Tin O2n-1 toward the oxygen reduction reaction(ORR) in 0.5 mol/L H2SO4 solution were investigated through the accelerated aging tests(AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V(vs SCE), the specific kinetic current density of the ORR on the Pt/Tin O2n-1 is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/Tin O2n-1. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on Tin O2n-1 remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2times that of the Pt/Tin O2n-1. The superior catalytic stability of Pt/Tin O2n-1 toward the ORR could be attributed to the excellent stability of the Tin O2n-1 and the electronic interaction between the metals and the support.展开更多
Flow anodic oxidation system has demonstrated to be a promising and environmental benign water treatment technology because of its advantages of high contaminant removal efficiency and low energy consumption.However,t...Flow anodic oxidation system has demonstrated to be a promising and environmental benign water treatment technology because of its advantages of high contaminant removal efficiency and low energy consumption.However,traditional setup needs an external unit for flow anode material separation and recovery,which inevitably increases the capital cost and hinders its continuous operation.Herein,a specific porous cathode is introduced to achieve continuous water purification with high contaminant removal in a flow anodic oxidation system.The efuent concentration of carbamazepine(CBZ),a common and model contaminant widely detected in natural water environment,was reduced by 99%.The linear sweep voltammetry(LSV)and quenching tests demonstrated that HO·was the dominant reactive species.While the removal of contaminants was inhibited in practical surface water,largely related to the quenching by dissolved organic matter and bicarbonate,the flow anodic oxidation process was competent in alleviating the ecotoxicity following oxidation.Our study constructs a modular device for cost-effective continuous water purification and provides insight into the mechanisms of flow andic oxidation.展开更多
Magn-eli,a fascinating sub-stoichiometric titanium oxide phase that contains oxygen vacancies of TiO_(2),is proposed as a potential photo-electrode for photocatalysis due to its high conductivity and photoelectric con...Magn-eli,a fascinating sub-stoichiometric titanium oxide phase that contains oxygen vacancies of TiO_(2),is proposed as a potential photo-electrode for photocatalysis due to its high conductivity and photoelectric conversion efficiency.In this work,partially reduced porous TiO_(2) ceramics with a graded reduction profile and an aligned pore structure were prepared by carbo-thermal reduction of freeze-cast TiO_(2) with a range of porosities from 10 to 30 vol.%.AC conductivity evaluation revealed that the oxygen vacancies that exist in Magn-eli lead to a relatively high AC conductivity of~10 S/m at 1 kHz,as compared to that of the stoichiometric porous TiO_(2).A maximum photocurrent density and incident photon-to-current efficiency(IPCE)of 9.14 mA/cm^(2) and 40.52%respectively were achieved from the gradient porous Magn-eli with a porosity of 30 vol.%.展开更多
Pancreatic ductal adenocarcinoma is the most common malignant tumor of the pancreas. The remaining pancreatic tumors are a diverse group of pancreatic neoplasms that comprises cystic pancreatic neoplasms, endocrine tu...Pancreatic ductal adenocarcinoma is the most common malignant tumor of the pancreas. The remaining pancreatic tumors are a diverse group of pancreatic neoplasms that comprises cystic pancreatic neoplasms, endocrine tumors and other uncommon pancreatic tumors. Due to the excellent soft tissue contrast resolution, magnetic resonance imaging(MRI) is frequently able to readily separate cystic from noncystic tumors. Cystic tumors are often easy to diagnose with MRI; however, noncystic non-adenocarcinoma tumors may show a wide spectrum of imaging features, which can potentially mimic ductal adenocarcinoma. MRI is a reliable technique for the characterization of pancreatic lesions. The implementation of novel motionresistant pulse sequences and respiratory gating techniques, as well as the recognized benefits of MR cholangiopancreatography, make MRI a very accurate examination for the evaluation of pancreatic masses. MRI has the distinctive ability of non-invasive assessment of the pancreatic ducts, pancreatic parenchyma, neighbouring soft tissues, and vascular network in one examination. MRI can identify different characteristics of various solid pancreatic lesions, potentially allowing the differentiation of adenocarcinoma from other benign and malignant entities. In this review we describe the MRI protocols and MRI characteristics of various solid pancreatic lesions. Recognition of these characteristics may establish the right diagnosis or at least narrow the differential diagnosis, thus avoiding unnecessary tests or procedures and permitting better management.展开更多
基金Project(21406273)supported by the National Natural Science Foundation of China
文摘Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-reduction method. The electrochemical stability of Tin O2n-1 was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V(vs NHE) in 0.5 mol/L H2SO4 aqueous solution. The catalytic activity and stability of the Pt/Tin O2n-1 toward the oxygen reduction reaction(ORR) in 0.5 mol/L H2SO4 solution were investigated through the accelerated aging tests(AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V(vs SCE), the specific kinetic current density of the ORR on the Pt/Tin O2n-1 is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/Tin O2n-1. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on Tin O2n-1 remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2times that of the Pt/Tin O2n-1. The superior catalytic stability of Pt/Tin O2n-1 toward the ORR could be attributed to the excellent stability of the Tin O2n-1 and the electronic interaction between the metals and the support.
基金financially supported by the Basic Science Center Project of the National Natural Science Foundation of China(No.52388101)Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2019ZT08L213)the National Natural Science Foundation of China(No.52100030)。
文摘Flow anodic oxidation system has demonstrated to be a promising and environmental benign water treatment technology because of its advantages of high contaminant removal efficiency and low energy consumption.However,traditional setup needs an external unit for flow anode material separation and recovery,which inevitably increases the capital cost and hinders its continuous operation.Herein,a specific porous cathode is introduced to achieve continuous water purification with high contaminant removal in a flow anodic oxidation system.The efuent concentration of carbamazepine(CBZ),a common and model contaminant widely detected in natural water environment,was reduced by 99%.The linear sweep voltammetry(LSV)and quenching tests demonstrated that HO·was the dominant reactive species.While the removal of contaminants was inhibited in practical surface water,largely related to the quenching by dissolved organic matter and bicarbonate,the flow anodic oxidation process was competent in alleviating the ecotoxicity following oxidation.Our study constructs a modular device for cost-effective continuous water purification and provides insight into the mechanisms of flow andic oxidation.
基金Key Research and Development Project of Hunan Province,China(No.2020WK2004)Hundred Youth Talents Program of Hunan,China,Overseas Talent Introduction Project of China,the Academy of Medical Sciences GCRF Fund,China(GCRFNGR2-10059)The Leverhulme Trust(RGP-2018-290)for their support.
文摘Magn-eli,a fascinating sub-stoichiometric titanium oxide phase that contains oxygen vacancies of TiO_(2),is proposed as a potential photo-electrode for photocatalysis due to its high conductivity and photoelectric conversion efficiency.In this work,partially reduced porous TiO_(2) ceramics with a graded reduction profile and an aligned pore structure were prepared by carbo-thermal reduction of freeze-cast TiO_(2) with a range of porosities from 10 to 30 vol.%.AC conductivity evaluation revealed that the oxygen vacancies that exist in Magn-eli lead to a relatively high AC conductivity of~10 S/m at 1 kHz,as compared to that of the stoichiometric porous TiO_(2).A maximum photocurrent density and incident photon-to-current efficiency(IPCE)of 9.14 mA/cm^(2) and 40.52%respectively were achieved from the gradient porous Magn-eli with a porosity of 30 vol.%.
文摘Pancreatic ductal adenocarcinoma is the most common malignant tumor of the pancreas. The remaining pancreatic tumors are a diverse group of pancreatic neoplasms that comprises cystic pancreatic neoplasms, endocrine tumors and other uncommon pancreatic tumors. Due to the excellent soft tissue contrast resolution, magnetic resonance imaging(MRI) is frequently able to readily separate cystic from noncystic tumors. Cystic tumors are often easy to diagnose with MRI; however, noncystic non-adenocarcinoma tumors may show a wide spectrum of imaging features, which can potentially mimic ductal adenocarcinoma. MRI is a reliable technique for the characterization of pancreatic lesions. The implementation of novel motionresistant pulse sequences and respiratory gating techniques, as well as the recognized benefits of MR cholangiopancreatography, make MRI a very accurate examination for the evaluation of pancreatic masses. MRI has the distinctive ability of non-invasive assessment of the pancreatic ducts, pancreatic parenchyma, neighbouring soft tissues, and vascular network in one examination. MRI can identify different characteristics of various solid pancreatic lesions, potentially allowing the differentiation of adenocarcinoma from other benign and malignant entities. In this review we describe the MRI protocols and MRI characteristics of various solid pancreatic lesions. Recognition of these characteristics may establish the right diagnosis or at least narrow the differential diagnosis, thus avoiding unnecessary tests or procedures and permitting better management.
