It is a fact that the near surface loess has magnetic susceptibility anomalies in oil and gas areas. Why these anomalies occur and whether they have any significant value for the exploration of oil and gas reservoirs ...It is a fact that the near surface loess has magnetic susceptibility anomalies in oil and gas areas. Why these anomalies occur and whether they have any significant value for the exploration of oil and gas reservoirs are questions that geophysicists are mostly concerned about and study. We analyze the cause of the formation of surface loess susceptibility anomalies in oil and gas areas, process the observations of the susceptibility of loess samples taken from an oil and gas area in western China with proper mathematical methods, and determine the background value of loess susceptibility. These results are used to determine oil and gas prospect areas with a numeric evaluation factor based on the susceptibility anomalies. Actual oil wells have verified that using the susceptibility anomalies to indicate the location of oil and gas reservoirs is valid.展开更多
In the 1940s,Wang Zhenduo王振铎re-created the sinan司南(southpointing loadstone spoon)mentioned in ancient texts.However,subsequent researchers were unsuccessful in their attempts to replicate this design,resulting in...In the 1940s,Wang Zhenduo王振铎re-created the sinan司南(southpointing loadstone spoon)mentioned in ancient texts.However,subsequent researchers were unsuccessful in their attempts to replicate this design,resulting in longstanding questions over its feasibility.Loadstones with high natural remanent magnetization acquired today resemble the magnetism of those recorded in premodern Chinese documents.By simulating ancient stoneware processing techniques,a loadstone was cut and polished into a spoon shape.It was found that during the course of processing the loadstone spoon,demagnetization was negligible,while after completion,the internal magnetic field was rebalanced due to the change in shape,and the magnetic moment decreased slightly then stabilized for the long term.Experiments of this sort carried out by the author have testified to the enduring and reliable directivity of the resulting loadstone spoon.Paleo-magnetic research indicates that over the past two millennia the horizontal component of the geomagnetic field intensity in northern China underwent a clear M-shaped development.The level in the Qin and Han dynasties is approximately double that of the current day.Using a simulated ancient geomagnetic field,experiments have revealed that multiple methods,such as the“water floating method”and“hanging method,”could manifest a degree of geo-directivity.The comprehensive studies carried out demonstrate that the loadstone spoon is the most optimal among these diverse means for attaining magnetic directivity from the Pre-Qin period(before 221 BCE)to the Tang dynasty(618–907 CE)in view of the availability of loadstone,the state of the geomagnetic field,and existing knowledge and techniques。展开更多
One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron sourc...One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron source.A chelating polycarboxylic acid such as citric acid(CA)was employed as the carbon source,and it dissolved Fe very effectively,Fe3O4 and natural magnetite to composite an iron-citrate complex with the assistance of ammonium hydroxide.The core-shell structure of the as-prepared nanocomposites was formed directly by high-temperature pyrolysis.The Fe3C@C materials exhibited superparamagnetic properties(38.09 emu/mg),suggesting potential applications in biomedicine,environment,absorption,catalysis,etc.展开更多
文摘It is a fact that the near surface loess has magnetic susceptibility anomalies in oil and gas areas. Why these anomalies occur and whether they have any significant value for the exploration of oil and gas reservoirs are questions that geophysicists are mostly concerned about and study. We analyze the cause of the formation of surface loess susceptibility anomalies in oil and gas areas, process the observations of the susceptibility of loess samples taken from an oil and gas area in western China with proper mathematical methods, and determine the background value of loess susceptibility. These results are used to determine oil and gas prospect areas with a numeric evaluation factor based on the susceptibility anomalies. Actual oil wells have verified that using the susceptibility anomalies to indicate the location of oil and gas reservoirs is valid.
文摘In the 1940s,Wang Zhenduo王振铎re-created the sinan司南(southpointing loadstone spoon)mentioned in ancient texts.However,subsequent researchers were unsuccessful in their attempts to replicate this design,resulting in longstanding questions over its feasibility.Loadstones with high natural remanent magnetization acquired today resemble the magnetism of those recorded in premodern Chinese documents.By simulating ancient stoneware processing techniques,a loadstone was cut and polished into a spoon shape.It was found that during the course of processing the loadstone spoon,demagnetization was negligible,while after completion,the internal magnetic field was rebalanced due to the change in shape,and the magnetic moment decreased slightly then stabilized for the long term.Experiments of this sort carried out by the author have testified to the enduring and reliable directivity of the resulting loadstone spoon.Paleo-magnetic research indicates that over the past two millennia the horizontal component of the geomagnetic field intensity in northern China underwent a clear M-shaped development.The level in the Qin and Han dynasties is approximately double that of the current day.Using a simulated ancient geomagnetic field,experiments have revealed that multiple methods,such as the“water floating method”and“hanging method,”could manifest a degree of geo-directivity.The comprehensive studies carried out demonstrate that the loadstone spoon is the most optimal among these diverse means for attaining magnetic directivity from the Pre-Qin period(before 221 BCE)to the Tang dynasty(618–907 CE)in view of the availability of loadstone,the state of the geomagnetic field,and existing knowledge and techniques。
基金supported by the National Natural Science Foundation of China(No.51876046 and No.51711540032)。
文摘One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron source.A chelating polycarboxylic acid such as citric acid(CA)was employed as the carbon source,and it dissolved Fe very effectively,Fe3O4 and natural magnetite to composite an iron-citrate complex with the assistance of ammonium hydroxide.The core-shell structure of the as-prepared nanocomposites was formed directly by high-temperature pyrolysis.The Fe3C@C materials exhibited superparamagnetic properties(38.09 emu/mg),suggesting potential applications in biomedicine,environment,absorption,catalysis,etc.
