This essay focused on comparing and contrasts audio lingual method and Task-based language teaching method,demonstrating the strengths and weaknesses of the two methods and discusses how they impact upon both the teac...This essay focused on comparing and contrasts audio lingual method and Task-based language teaching method,demonstrating the strengths and weaknesses of the two methods and discusses how they impact upon both the teachers and the learners.TBLT is the contemporary teaching method with a great number of strong points.It seems that if there is more relatively scientific and effective method,TBLT should give way to it.The ultimate goal is to advocate the comparatively successful teaching method in the field of foreign language education.展开更多
Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ult...Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ultrasound is two-to three-orders magnitude weaker than that of light, photoacoustic imaging can effectively improve the imaging depth.However, as the depth of imaging further increases, the incident light is seriously affected by scattering that the generated photoacoustic signal is very weak and the signal-to-noise ratio(SNR) is quite low. Low SNR signals can reduce imaging quality and even cause imaging failure. In this paper, we proposed a new wavefront shaping and imaging method of low SNR photoacoustic signal using digital micromirror device(DMD) based superpixel method. We combined the superpixel method with DMD to modulate the phase and amplitude of the incident light, and the genetic algorithm(GA) was used as the wavefront shaping algorithm. The enhancement of the photoacoustic signal reached 10.46. Then we performed scanning imaging by moving the absorber with the translation stage. A clear image with contrast of 8.57 was obtained while imaging with original photoacoustic signals could not be achieved. The proposed method opens new perspectives for imaging with weak photoacoustic signals.展开更多
As one of the most exciting inspection and powerful analysis methods in modern materials metallographic examinations, the difference interference contrast (DIC) method has many advantages, including relatively low req...As one of the most exciting inspection and powerful analysis methods in modern materials metallographic examinations, the difference interference contrast (DIC) method has many advantages, including relatively low requirement for specimen preparation, obvious relief senses observed under microscope. Details such as fine structures or defects that are not or barely visible in incident-light bright field, could be easily revealed and thus make materials analysis more reliable. Differential interference contrast produces an image that can be readily manipulated using digital and video imaging techniques to further enhance contrast. But, studies of material metallography based on DIC method have rarely carried out. Based on the fundamental principle of the DIC method combing with the computer image analysis, applications of DIC method in materials metallographic examination were investigated in this study.展开更多
Recent studies indicated that except for the land-sea thermal contrast,there also existed the land-land thermal contrast.The composite analysis and t-test method are used to further study the local thermal contrast va...Recent studies indicated that except for the land-sea thermal contrast,there also existed the land-land thermal contrast.The composite analysis and t-test method are used to further study the local thermal contrast variation over the Asian continent,and to discuss the association of seasonal variation of land thermal state with circulation over East Asia,the early summer and summer monsoon activity,and the precipitation anomaly in China in the decadal scale.Results show that the positive meridional temperature anomaly transports downward from upper tropospheric layers in middle-high latitudes north of 25°N in the positive years.In the zonal direction,the Tibetan Plateau heating in the successive spring acts as a force to influence the atmosphere,leading to the rapid temperature warming over eastern Chinese continent,which could increase the land-sea thermal contrast with the negative SSTA.Accordingly,the monsoon activity in early summer over East Asian establishes earlier and the summer monsoon intensity becomes stronger.The early summer precipitation is more-than-normal over the Yangtze River,and the summer precipitation is more-than-normal over the north China and the southwest China.The situation is contrary in the negative years.展开更多
文摘This essay focused on comparing and contrasts audio lingual method and Task-based language teaching method,demonstrating the strengths and weaknesses of the two methods and discusses how they impact upon both the teachers and the learners.TBLT is the contemporary teaching method with a great number of strong points.It seems that if there is more relatively scientific and effective method,TBLT should give way to it.The ultimate goal is to advocate the comparatively successful teaching method in the field of foreign language education.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFB1104500)the Beijing Natural Science Foundation,China(Grant No.7182091)+1 种基金the National Natural Science Foundation of China(Grant No.21627813)the Research Projects on Biomedical Transformation of China–Japan Friendship Hospital(Grant No.PYBZ1801)。
文摘Photoacoustic(PA) imaging has drawn tremendous research interest for various applications in biomedicine and experienced exponential growth over the past decade. Since the scattering effect of biological tissue on ultrasound is two-to three-orders magnitude weaker than that of light, photoacoustic imaging can effectively improve the imaging depth.However, as the depth of imaging further increases, the incident light is seriously affected by scattering that the generated photoacoustic signal is very weak and the signal-to-noise ratio(SNR) is quite low. Low SNR signals can reduce imaging quality and even cause imaging failure. In this paper, we proposed a new wavefront shaping and imaging method of low SNR photoacoustic signal using digital micromirror device(DMD) based superpixel method. We combined the superpixel method with DMD to modulate the phase and amplitude of the incident light, and the genetic algorithm(GA) was used as the wavefront shaping algorithm. The enhancement of the photoacoustic signal reached 10.46. Then we performed scanning imaging by moving the absorber with the translation stage. A clear image with contrast of 8.57 was obtained while imaging with original photoacoustic signals could not be achieved. The proposed method opens new perspectives for imaging with weak photoacoustic signals.
文摘As one of the most exciting inspection and powerful analysis methods in modern materials metallographic examinations, the difference interference contrast (DIC) method has many advantages, including relatively low requirement for specimen preparation, obvious relief senses observed under microscope. Details such as fine structures or defects that are not or barely visible in incident-light bright field, could be easily revealed and thus make materials analysis more reliable. Differential interference contrast produces an image that can be readily manipulated using digital and video imaging techniques to further enhance contrast. But, studies of material metallography based on DIC method have rarely carried out. Based on the fundamental principle of the DIC method combing with the computer image analysis, applications of DIC method in materials metallographic examination were investigated in this study.
基金Natural Science Fund projects of China(40675045,41065004)NSFC-Yunnan Joint Foundation(U0833602)National Public Benefit Research Foundation of China(GYHY201206017)
文摘Recent studies indicated that except for the land-sea thermal contrast,there also existed the land-land thermal contrast.The composite analysis and t-test method are used to further study the local thermal contrast variation over the Asian continent,and to discuss the association of seasonal variation of land thermal state with circulation over East Asia,the early summer and summer monsoon activity,and the precipitation anomaly in China in the decadal scale.Results show that the positive meridional temperature anomaly transports downward from upper tropospheric layers in middle-high latitudes north of 25°N in the positive years.In the zonal direction,the Tibetan Plateau heating in the successive spring acts as a force to influence the atmosphere,leading to the rapid temperature warming over eastern Chinese continent,which could increase the land-sea thermal contrast with the negative SSTA.Accordingly,the monsoon activity in early summer over East Asian establishes earlier and the summer monsoon intensity becomes stronger.The early summer precipitation is more-than-normal over the Yangtze River,and the summer precipitation is more-than-normal over the north China and the southwest China.The situation is contrary in the negative years.
