Organic coatings are widely used to control the corrosion of steel structure. The anticorrosive property of these coatings depends on their barrier properties, making a separation between the corrosive medium and the ...Organic coatings are widely used to control the corrosion of steel structure. The anticorrosive property of these coatings depends on their barrier properties, making a separation between the corrosive medium and the substrate. But unavoidable completely small pores, cracks and other defects in organic coatings may cause ions, water, gases, and other corrosive species penetrate and distribute in the coatings, causing accumulation and swelling of coatings, so leading to the degradation of coatings. In addition, water affects the permeation of oxygen and other corrosive medium, consequently the presence of such substances at coating-metal interface promotes corrosion of metal substrate. So the absorbability of the coatings to water may be one of the most important factors in undercoating corrosion. In recent years, electrochemical impedance spectroscopy (EIS) has been established and frequently used as a non-destructive testing method for assessing the performance of organic coatings, especially for the determination of the water content in organic coatings, since the capacitance of the coatings is sensitive to the penetration of water. So from EIS it can extract a wealth of information on the electrochemical corrosion of coated steels, especially, it can be utilized to assess organic coatings used under particular surroundings. The principle, methods and application of EIS on evaluating life-span and analyzing failure mechanism of organic coatings are also introduced briefly. Combining other analysis techniques such as XRD, SEM and FTIR with electrochemical technique, it will blaze a way in studying degradation mechanism of organic coatings and estimating their lifetime.展开更多
The effective energy loss functions for Al have been derived from differential i nverse inelastic mean free path based on the extended Landau approach. It has be en revealed that the effective energy loss function is ...The effective energy loss functions for Al have been derived from differential i nverse inelastic mean free path based on the extended Landau approach. It has be en revealed that the effective energy loss function is very close in value to th e theoretical surface energy loss function in the lower energy loss region but g radually approaches the theoretical bulk energy loss function in the higher ener gy loss region. Moreover, the intensity corresponding to surface excitation in e ffective energy loss functions decreases with the increase of primary electron e nergy. These facts show that the present effective energy loss function describe s not only surface excitation but also bulk excitation. At last, REELS spectra s imulated by Monte Carlo method based on use of the effective energy loss functio ns has reproduced the experimental REELS spectra with considerable success.展开更多
Stroke is a major health concern and an intensive research subject due that it is the major cause of death and the leading cause of disability worldwide. The past three decades of clinical disappointments in treating ...Stroke is a major health concern and an intensive research subject due that it is the major cause of death and the leading cause of disability worldwide. The past three decades of clinical disappointments in treating stroke must compel us to rethink our strategy. New effective protocol for stroke could greatly benefit from the advances in optical imaging technologies. This review focuses on the latest advance of applications of three optical imaging techniques in animal model of stroke, such as photoacoustic （PA） imaging, laser speckle contrast imaging （LSCI） and two-photon microscopy （TPM）. The potential roles of those techniques in the future of stroke management are also discussed.展开更多
文摘Organic coatings are widely used to control the corrosion of steel structure. The anticorrosive property of these coatings depends on their barrier properties, making a separation between the corrosive medium and the substrate. But unavoidable completely small pores, cracks and other defects in organic coatings may cause ions, water, gases, and other corrosive species penetrate and distribute in the coatings, causing accumulation and swelling of coatings, so leading to the degradation of coatings. In addition, water affects the permeation of oxygen and other corrosive medium, consequently the presence of such substances at coating-metal interface promotes corrosion of metal substrate. So the absorbability of the coatings to water may be one of the most important factors in undercoating corrosion. In recent years, electrochemical impedance spectroscopy (EIS) has been established and frequently used as a non-destructive testing method for assessing the performance of organic coatings, especially for the determination of the water content in organic coatings, since the capacitance of the coatings is sensitive to the penetration of water. So from EIS it can extract a wealth of information on the electrochemical corrosion of coated steels, especially, it can be utilized to assess organic coatings used under particular surroundings. The principle, methods and application of EIS on evaluating life-span and analyzing failure mechanism of organic coatings are also introduced briefly. Combining other analysis techniques such as XRD, SEM and FTIR with electrochemical technique, it will blaze a way in studying degradation mechanism of organic coatings and estimating their lifetime.
基金This work was supported by the National Natural Science Foundation of China(No.10025420,No.20075026,No.60306006 and No.90206009)the post-doctoral fellowship provided by a Grant-in-Aid for Creative Scientific Research of Japanese govermment(No.13GS0022).The authors would also like to thank Dr.H.Yoshikawa,National Institute for Materials Science of Japan,and Dr.T.Nagatomi,Osaka University,for their helpful comments.
文摘The effective energy loss functions for Al have been derived from differential i nverse inelastic mean free path based on the extended Landau approach. It has be en revealed that the effective energy loss function is very close in value to th e theoretical surface energy loss function in the lower energy loss region but g radually approaches the theoretical bulk energy loss function in the higher ener gy loss region. Moreover, the intensity corresponding to surface excitation in e ffective energy loss functions decreases with the increase of primary electron e nergy. These facts show that the present effective energy loss function describe s not only surface excitation but also bulk excitation. At last, REELS spectra s imulated by Monte Carlo method based on use of the effective energy loss functio ns has reproduced the experimental REELS spectra with considerable success.
文摘Stroke is a major health concern and an intensive research subject due that it is the major cause of death and the leading cause of disability worldwide. The past three decades of clinical disappointments in treating stroke must compel us to rethink our strategy. New effective protocol for stroke could greatly benefit from the advances in optical imaging technologies. This review focuses on the latest advance of applications of three optical imaging techniques in animal model of stroke, such as photoacoustic （PA） imaging, laser speckle contrast imaging （LSCI） and two-photon microscopy （TPM）. The potential roles of those techniques in the future of stroke management are also discussed.
