Nitrogen-doped（N-doped） graphene has attracted increasing attentions because of the significantly enhanced properties in physic, chemistry, biology and material science, as compared with those of pristine graphene. ...Nitrogen-doped（N-doped） graphene has attracted increasing attentions because of the significantly enhanced properties in physic, chemistry, biology and material science, as compared with those of pristine graphene. By date, N-doped graphene has opened up an exciting new field in the science and technology of two-dimensional materials. From the viewpoints of chemistry and materials, this article presents an overview on the recent progress of N-doped graphene, including the typical synthesis methods, characterization techniques, and various applications in energy fields. The challenges and perspective of Ndoped graphene are also discussed. We expect that this review will provide new insights into the further development and practical applications of N-doped graphene.展开更多
Surface-enhanced Raman Spectroscopy(SERS)has been used to characterize hurnic substances.By using HNO_3 -roughened silver foils as the enhancing surface,both fluorescence quenching and strong SERS signals have been ob...Surface-enhanced Raman Spectroscopy(SERS)has been used to characterize hurnic substances.By using HNO_3 -roughened silver foils as the enhancing surface,both fluorescence quenching and strong SERS signals have been observed at the same time.The results obtained herein show that SERS is a particularly sensitive and highly selective technique for the characterization of humic substances in the environment. Humic substances axe receiving ever-inereasing attention because of their importance in the environment. Very recently,we have reported the first successful application of Raman spectroscopy for characterizing humic substances.In this present paper,the application of surface-enhanced Raman spectroscopy(SERS)for humic substances has further been investigated.To our knowledge,no such studies have previously been reported.The results obtained herein dearly demonstrate that SERS has a great deal of promise as an analytical method for“In Situ”characterizing humic substances in the environment.展开更多
The femtosecond laser pulses reflected from the self-induced plasma mirror（PM） surface are characterized. More than two orders of magnitude improvement on intensity contrast both in nanosecond and picosecond tempora...The femtosecond laser pulses reflected from the self-induced plasma mirror（PM） surface are characterized. More than two orders of magnitude improvement on intensity contrast both in nanosecond and picosecond temporal scales are measured. The far-field distribution, i.e., focusability, is measured to degrade in comparison with that without using a PM. Experiments on proton accelerations are performed to test the effect of the balance between degraded focusability and increased reflectivity. Our results show that PM is an effective and robust device to improve laser contrast for applications.展开更多
When using the current popular text recognition algorithms such as optical character recognition(OCR)algorithm for text images,the presence of watermarks in text images interferes with algorithm recognition to the ext...When using the current popular text recognition algorithms such as optical character recognition(OCR)algorithm for text images,the presence of watermarks in text images interferes with algorithm recognition to the extent of fuzzy font,which is not conducive to the improvement of the recognition rate.In order to pursue fast and high recognition rate,watermark removal has become a critical problem to be solved.This work studies the watermarking algorithm based on morphological algorithm set and classic image algorithm in computer images.It can not only remove the watermark in a short time,but also keep the form and clarity of the text in the image.The algorithm also meets the requirements that the higher the clarity of image and text,the better the processing effect.It can process the Chinese characters with complex structure,complicated radicals or other characters well.In addition,the algorithm can basically process ordinary size images in 1 s,the efficiency is relatively high.展开更多
We give a new characterization of the paratingent cone in terms of contingent cones,i. e., the paratingent cone to any open set at a boundary point is the upper limit of the contingentcones at the neighboring points. ...We give a new characterization of the paratingent cone in terms of contingent cones,i. e., the paratingent cone to any open set at a boundary point is the upper limit of the contingentcones at the neighboring points. We use this result to characterize the strict differentiability in termsof the contingent directional derivatives. We also define a P-subderivative for continuous functionsand develop a subdifferential calculus with applications to optimality conditions in mathematicalprograming.展开更多
基金supported by the National Key R&D Program of China(2017YFA0208200,2016YFB0700600,2015CB659300)Projects of NSFC(21403105,21573108)+2 种基金Anhui Provincial Key Research and Development Program(1704A0902022)Natural Science Foundation of Jiangsu Province(BK20150583,BK20160647)the Fundamental Research Funds for the Central Universities(020514380107)
文摘Nitrogen-doped（N-doped） graphene has attracted increasing attentions because of the significantly enhanced properties in physic, chemistry, biology and material science, as compared with those of pristine graphene. By date, N-doped graphene has opened up an exciting new field in the science and technology of two-dimensional materials. From the viewpoints of chemistry and materials, this article presents an overview on the recent progress of N-doped graphene, including the typical synthesis methods, characterization techniques, and various applications in energy fields. The challenges and perspective of Ndoped graphene are also discussed. We expect that this review will provide new insights into the further development and practical applications of N-doped graphene.
文摘Surface-enhanced Raman Spectroscopy(SERS)has been used to characterize hurnic substances.By using HNO_3 -roughened silver foils as the enhancing surface,both fluorescence quenching and strong SERS signals have been observed at the same time.The results obtained herein show that SERS is a particularly sensitive and highly selective technique for the characterization of humic substances in the environment. Humic substances axe receiving ever-inereasing attention because of their importance in the environment. Very recently,we have reported the first successful application of Raman spectroscopy for characterizing humic substances.In this present paper,the application of surface-enhanced Raman spectroscopy(SERS)for humic substances has further been investigated.To our knowledge,no such studies have previously been reported.The results obtained herein dearly demonstrate that SERS has a great deal of promise as an analytical method for“In Situ”characterizing humic substances in the environment.
基金supported by National Basic Research Program of China (No. 2013CBA01502)the National Natural Science Foundation of China (Nos. 11121504, 11205100, and 11305103)the National Key Scientific Instrument Development Project (No. 2012YQ030142)
文摘The femtosecond laser pulses reflected from the self-induced plasma mirror（PM） surface are characterized. More than two orders of magnitude improvement on intensity contrast both in nanosecond and picosecond temporal scales are measured. The far-field distribution, i.e., focusability, is measured to degrade in comparison with that without using a PM. Experiments on proton accelerations are performed to test the effect of the balance between degraded focusability and increased reflectivity. Our results show that PM is an effective and robust device to improve laser contrast for applications.
基金Supported by the National Entrepreneurship Training Fund Project(No.201810573007X)China Scholarship Council Project(No.201708440547)GDPU Higher Education Innovation Strong School Project(No.2017GXJK079,51359055)。
文摘When using the current popular text recognition algorithms such as optical character recognition(OCR)algorithm for text images,the presence of watermarks in text images interferes with algorithm recognition to the extent of fuzzy font,which is not conducive to the improvement of the recognition rate.In order to pursue fast and high recognition rate,watermark removal has become a critical problem to be solved.This work studies the watermarking algorithm based on morphological algorithm set and classic image algorithm in computer images.It can not only remove the watermark in a short time,but also keep the form and clarity of the text in the image.The algorithm also meets the requirements that the higher the clarity of image and text,the better the processing effect.It can process the Chinese characters with complex structure,complicated radicals or other characters well.In addition,the algorithm can basically process ordinary size images in 1 s,the efficiency is relatively high.
文摘We give a new characterization of the paratingent cone in terms of contingent cones,i. e., the paratingent cone to any open set at a boundary point is the upper limit of the contingentcones at the neighboring points. We use this result to characterize the strict differentiability in termsof the contingent directional derivatives. We also define a P-subderivative for continuous functionsand develop a subdifferential calculus with applications to optimality conditions in mathematicalprograming.
