The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particle...The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay. On the surface of BS, both toluene insoluble organic matter and structural OH group are detected at the same time. The surface characteristics imparted a bi-wettable nature to the BS. As a result, the BS is able to stabilize fine water emulsion in the bitumen phase. The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.展开更多
This work investigated the effect of process parameters on densification,microstructure,and mechanical properties of a nickel-aluminum-bronze(NAB)alloy fabricated by laser powder bed fusion(LPBF)additive manufacturing...This work investigated the effect of process parameters on densification,microstructure,and mechanical properties of a nickel-aluminum-bronze(NAB)alloy fabricated by laser powder bed fusion(LPBF)additive manufacturing.The LPBF-printed NAB alloy samples with relative densities of over 98.5%were obtained under the volumetric energy density range of 200−250 J/mm^(3).The microstructure of the NAB alloy printed in both horizontal and vertical planes primarily consisted ofβ'martensitic phase and bandedαphase.In particular,a coarser-columnar grain structure and stronger crystallographic texture were achieved in the vertical plane,where the maximum texture intensity was 30.56 times greater than that of random textures at the(100)plane.Increasing the volumetric energy density resulted in a decrease in the columnar grain size,while increasing the amount ofαphase.Notably,β_(1)'martensitic structures with nanotwins and nanoscaleκ-phase precipitates were identified in the microstructure of LPBF-printed NAB samples with a volumetric energy density of 250 J/mm^(3).Furthermore,under optimal process parameters with a laser power of 350 W and scanning speed of 800 mm/s,significant improvements were observed in the microhardness(HV 386)and ultimate tensile strength(671 MPa),which was attributed to an increase in refined acicular martensite.展开更多
Chronologies of glacial advances during the last glacial period in the Nyainqentanglha mountain range may provide constraints on the past climate in a transition zone of the Asian monsoon. We present 15 new Be exposur...Chronologies of glacial advances during the last glacial period in the Nyainqentanglha mountain range may provide constraints on the past climate in a transition zone of the Asian monsoon. We present 15 new Be exposure ages from two moraines in the Payuwang valley, on the north slope of the range. The inner moraine has exposure ages ranging from 18.0±1.7 to 30.6±2.8 ka （n=10）, with a mean age of 23.8±4.0 ka, corresponding to the global Last Glacial Maximum （LGM）. The outer moraine yields exposure ages ranging from 18.0±1.6 to 39.9±3.7 ka （n=5）. Evidence for weathering leads us to view the oldest age as a mini mum age, placing moraine formation during MIS3. Chronologies from the last glacial period from south slope of the Nyainqentanglha support this interpretation. Thus, there appears to have been a local LGM （LLGM） during MIS3 and a more limited glacial advance during the global LGM. Glacial advances during MIS3 in the Nyainqentanglha may correlate with mil lennialscale climate change （Heinrich events）.展开更多
Penicillium digitatum is the most important pathogen of postharvest citrus. Gene targeting can be done in P. digitatum using homologous recombination via Agrobacterium tumefaciens mediated transformation （ATMT）, but...Penicillium digitatum is the most important pathogen of postharvest citrus. Gene targeting can be done in P. digitatum using homologous recombination via Agrobacterium tumefaciens mediated transformation （ATMT）, but the frequencies are often very low. In the present study, we replaced the Ku80 homolog （a gene of the non-homologous end-joining （NHEJ） pathway） with the hygromycin resistance cassette （hph） by ATMT. No significant change in vegetative growth, conidiation, or pathogenicity was observed in KuSO-deficient strain （△dKuSO） of P. digitatum. However, using △pdKuSO as a targeting strain, the gene-targeting frequencies for both genes PdbrlA and PdmpkA were significantly increased. These results suggest that Ku80 plays an important role in homologous inte- gration and the created △PdKuSO strain would be a good candidate for rapid gene function analysis in P. digitatum.展开更多
基金Financially supported by the Opening Fund of National Key Laboratory of State Heavy Oil University of Petroleum+1 种基金 Beijing (2003-04) and the Scientific Research Foundation (SRF) for the Returned Overseas Chinese Scholars (ROCS) State Education Minis
文摘The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay. On the surface of BS, both toluene insoluble organic matter and structural OH group are detected at the same time. The surface characteristics imparted a bi-wettable nature to the BS. As a result, the BS is able to stabilize fine water emulsion in the bitumen phase. The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.
基金Project(2022A1515010304)supported by the Guangdong Basic and Applied Basic Research Foundation,ChinaProject(52305358)supported by the National Natural Science Foundation of China+2 种基金Project(2023QNRC001)supported by the Young Elite Scientists Sponsorship Program by China Association for Science and TechnologyProject(QT-2023-001)supported by the Young Talent Support Project of Guangzhou,ChinaProject(2023ZYGXZR061)supported by the Fundamental Research Funds for the Central Universities,China。
文摘This work investigated the effect of process parameters on densification,microstructure,and mechanical properties of a nickel-aluminum-bronze(NAB)alloy fabricated by laser powder bed fusion(LPBF)additive manufacturing.The LPBF-printed NAB alloy samples with relative densities of over 98.5%were obtained under the volumetric energy density range of 200−250 J/mm^(3).The microstructure of the NAB alloy printed in both horizontal and vertical planes primarily consisted ofβ'martensitic phase and bandedαphase.In particular,a coarser-columnar grain structure and stronger crystallographic texture were achieved in the vertical plane,where the maximum texture intensity was 30.56 times greater than that of random textures at the(100)plane.Increasing the volumetric energy density resulted in a decrease in the columnar grain size,while increasing the amount ofαphase.Notably,β_(1)'martensitic structures with nanotwins and nanoscaleκ-phase precipitates were identified in the microstructure of LPBF-printed NAB samples with a volumetric energy density of 250 J/mm^(3).Furthermore,under optimal process parameters with a laser power of 350 W and scanning speed of 800 mm/s,significant improvements were observed in the microhardness(HV 386)and ultimate tensile strength(671 MPa),which was attributed to an increase in refined acicular martensite.
基金supported by National Natural Science Foundation of China(Key Program)(Grant No.41230523)Strategic Priority Research Program(B) of the Chinese Academy of Sciences(Grant No.XDB01020300)National Natural Science Foundation of China(General Program)(Grant No.40971017)
文摘Chronologies of glacial advances during the last glacial period in the Nyainqentanglha mountain range may provide constraints on the past climate in a transition zone of the Asian monsoon. We present 15 new Be exposure ages from two moraines in the Payuwang valley, on the north slope of the range. The inner moraine has exposure ages ranging from 18.0±1.7 to 30.6±2.8 ka （n=10）, with a mean age of 23.8±4.0 ka, corresponding to the global Last Glacial Maximum （LGM）. The outer moraine yields exposure ages ranging from 18.0±1.6 to 39.9±3.7 ka （n=5）. Evidence for weathering leads us to view the oldest age as a mini mum age, placing moraine formation during MIS3. Chronologies from the last glacial period from south slope of the Nyainqentanglha support this interpretation. Thus, there appears to have been a local LGM （LLGM） during MIS3 and a more limited glacial advance during the global LGM. Glacial advances during MIS3 in the Nyainqentanglha may correlate with mil lennialscale climate change （Heinrich events）.
基金supported by the National Natural Science Foundation of China(Nos.31371961 and 31071649)the China Agriculture Research System(No.CARS-27)the Special Fund for Agro-scientific Research in the Public Interest(No.201203034),China
文摘Penicillium digitatum is the most important pathogen of postharvest citrus. Gene targeting can be done in P. digitatum using homologous recombination via Agrobacterium tumefaciens mediated transformation （ATMT）, but the frequencies are often very low. In the present study, we replaced the Ku80 homolog （a gene of the non-homologous end-joining （NHEJ） pathway） with the hygromycin resistance cassette （hph） by ATMT. No significant change in vegetative growth, conidiation, or pathogenicity was observed in KuSO-deficient strain （△dKuSO） of P. digitatum. However, using △pdKuSO as a targeting strain, the gene-targeting frequencies for both genes PdbrlA and PdmpkA were significantly increased. These results suggest that Ku80 plays an important role in homologous inte- gration and the created △PdKuSO strain would be a good candidate for rapid gene function analysis in P. digitatum.
