Low-voltage silicon （Si）-based light-emitting diode （LED） is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor （CMOS） technology. The low-voltage LED is de...Low-voltage silicon （Si）-based light-emitting diode （LED） is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor （CMOS） technology. The low-voltage LED is designed under the research of cross-finger structure LEDs and sophisticated structure enhanced LEDs for high efficiency and stable light source of monolithic chip integration. The device size of low-voltage LED is 45.85x38.4 （#m）, threshold voltage is 2.2 V in common condition, and temperature is 27 ~C. The external quantum efficiency is about 10-6 at stable operating state of 5 V and 177 mA.展开更多
Two methods：high-power,short-time,single-shot irradiation（Method A） and low-power,long-time,multi-shot irradiation（Method B） are investigated to mitigate the UV damage growth in fused silica by using a 10.6-μm C...Two methods：high-power,short-time,single-shot irradiation（Method A） and low-power,long-time,multi-shot irradiation（Method B） are investigated to mitigate the UV damage growth in fused silica by using a 10.6-μm CO2 laser.To verify the mitigation effect of the two methods,the laser induced damage thresholds（LIDTs） of the mitigated sites are tested with a 355-nm,6.4-ns Nd：YAG laser,and the light modulation of the mitigation sites are tested with a 351-nm continuous Nd：YLF laser.The mitigated damaged sites treated with the two methods have almost the same LIDTs,which can recover to the level of pristine material.Compared with Method A,Method B produces mitigated sites with low crater depth and weak light modulation.In addition,there is no raised rim or re-deposited debris formed around the crater edge for Method B.Theoretical calculation is utilized to evaluate the central temperature of the CO2 laser beam irradiated zone and the radius of the crater.It is indicated that the calculated results are consistent with the experimental results.展开更多
To demonstrate the existence of light thresholds in plant growth and to examine the effects of elevated CO2 on the shade tolerance of a tree species, an experiment consisting of a completely randomized design for a to...To demonstrate the existence of light thresholds in plant growth and to examine the effects of elevated CO2 on the shade tolerance of a tree species, an experiment consisting of a completely randomized design for a total of 96 yellow birch （Betula alleghaniensis Britton） seedlings was conducted with 3 light levels （2.9%, 7.7%, 26.1% of full sunlight） × 2 CO2 levels （350 and 700±10 ppm） with 4 replications in a phytotron. The study proved that thresholds exist and they vary in different plant organs. In ambient CO2, the thresholds were 13.3%, 18.7%, 15.0%, 15.2%, and 15.6% of full sunlight for stem, leaf, root, total plant biomass, and the averaged value, respectively. In 700 ppm CO2, the corresponding thresholds were 16.7%, 21.3%, 18.1%, 21.7% and 19.5% for stem, leaf, root, total plant biomass, and the averaged value, respectively. The lowest threshold in the stem is an indicator of the minimal light intensity for regular growth for seedlings of this species. Below this threshold, light-stressful growth occurs. The result of a paired t-test indicated that the thresholds in elevated CO2 were significantly higher than in ambient CO2. This suggests that yellow birch will lose its moderate shade tolerance, evolutionally becoming a shade-intolerant species, and that it may become more difficult to naturally regenerate in the future.展开更多
As the key principle of precision farming,the distribution of fractional vegetation cover is the basis of crop management within the field serves.To estimate crop FVC rapidly at the farm scale,high temporal-spatial re...As the key principle of precision farming,the distribution of fractional vegetation cover is the basis of crop management within the field serves.To estimate crop FVC rapidly at the farm scale,high temporal-spatial resolution imagery obtained by unmanned aerial vehicle(UAV)was adopted.To verify the application potential of consumer-grade UAV RGB imagery in estimated FVC,blue-green characteristic vegetation index(TBVI)and red-green vegetation index(TRVI)were proposed in this study according to the differences of the gray value among cotton vegetation,soil and shadow in the field.First,two new constructed indices and several published indices were used to extract visible light images and generate greyscale images for each of the visible light vegetation indices.Then,the thresholds of cotton vegetation and non-vegetation pixels were established based on the vegetation index threshold method which combines support vector machine classification and vegetation index.Finally,the accuracy difference in vegetation information extraction between the newly constructed and several published indices was compared.The results show that the accuracy of the information extracted by TRVI is higher than that of subdivision index of other visible light(FVC extraction precision in the first bud stage of cotton:R2=0.832,RMSE=2.307,nRMSE=4.405%;FVC extraction precision in the bud stage of cotton:R2=0.981,RMSE=1.393,nRMSE=1.984%;FVC extraction precision in the flowering stage of cotton:R2=0.893,RMSE=2.101,nRMSE=2.422%;FVC extraction precision in the boll stage of cotton:R2=0.958,RMSE=1.850,nRMSE=2.050%).展开更多
基金supported by the National Natural Science Foundation of China(Nos.61036002,60536030, 60776024,60877035,61076023,and 90820002)the National "863" Program of China(Nos.2007AA04Z329, 2007AA04Z254,2011CB933203,and 2011CB933102)
文摘Low-voltage silicon （Si）-based light-emitting diode （LED） is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor （CMOS） technology. The low-voltage LED is designed under the research of cross-finger structure LEDs and sophisticated structure enhanced LEDs for high efficiency and stable light source of monolithic chip integration. The device size of low-voltage LED is 45.85x38.4 （#m）, threshold voltage is 2.2 V in common condition, and temperature is 27 ~C. The external quantum efficiency is about 10-6 at stable operating state of 5 V and 177 mA.
基金Project supported by the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant No. 11076008)the Fundamental Research Funds for the Central Universities (Grant No. ZYGX2011J043)+1 种基金the Foundation for Young Scholars of University of Electronic Science and Technology of China (Grant No. 8010401JX0806)the Young Scientists Foundation of Sichuan Province of China (Grant No. 2010JQ0006)
文摘Two methods：high-power,short-time,single-shot irradiation（Method A） and low-power,long-time,multi-shot irradiation（Method B） are investigated to mitigate the UV damage growth in fused silica by using a 10.6-μm CO2 laser.To verify the mitigation effect of the two methods,the laser induced damage thresholds（LIDTs） of the mitigated sites are tested with a 355-nm,6.4-ns Nd：YAG laser,and the light modulation of the mitigation sites are tested with a 351-nm continuous Nd：YLF laser.The mitigated damaged sites treated with the two methods have almost the same LIDTs,which can recover to the level of pristine material.Compared with Method A,Method B produces mitigated sites with low crater depth and weak light modulation.In addition,there is no raised rim or re-deposited debris formed around the crater edge for Method B.Theoretical calculation is utilized to evaluate the central temperature of the CO2 laser beam irradiated zone and the radius of the crater.It is indicated that the calculated results are consistent with the experimental results.
文摘To demonstrate the existence of light thresholds in plant growth and to examine the effects of elevated CO2 on the shade tolerance of a tree species, an experiment consisting of a completely randomized design for a total of 96 yellow birch （Betula alleghaniensis Britton） seedlings was conducted with 3 light levels （2.9%, 7.7%, 26.1% of full sunlight） × 2 CO2 levels （350 and 700±10 ppm） with 4 replications in a phytotron. The study proved that thresholds exist and they vary in different plant organs. In ambient CO2, the thresholds were 13.3%, 18.7%, 15.0%, 15.2%, and 15.6% of full sunlight for stem, leaf, root, total plant biomass, and the averaged value, respectively. In 700 ppm CO2, the corresponding thresholds were 16.7%, 21.3%, 18.1%, 21.7% and 19.5% for stem, leaf, root, total plant biomass, and the averaged value, respectively. The lowest threshold in the stem is an indicator of the minimal light intensity for regular growth for seedlings of this species. Below this threshold, light-stressful growth occurs. The result of a paired t-test indicated that the thresholds in elevated CO2 were significantly higher than in ambient CO2. This suggests that yellow birch will lose its moderate shade tolerance, evolutionally becoming a shade-intolerant species, and that it may become more difficult to naturally regenerate in the future.
基金The authors gratefully acknowledge the financial support provided by Top Talents Program for One Case One Discussion of Shandong Province,China Agriculture Research System(Grant No.CARS-15-22)Natural Science Foundation of Shandong Province(Grant No.ZR2021MD091).
文摘As the key principle of precision farming,the distribution of fractional vegetation cover is the basis of crop management within the field serves.To estimate crop FVC rapidly at the farm scale,high temporal-spatial resolution imagery obtained by unmanned aerial vehicle(UAV)was adopted.To verify the application potential of consumer-grade UAV RGB imagery in estimated FVC,blue-green characteristic vegetation index(TBVI)and red-green vegetation index(TRVI)were proposed in this study according to the differences of the gray value among cotton vegetation,soil and shadow in the field.First,two new constructed indices and several published indices were used to extract visible light images and generate greyscale images for each of the visible light vegetation indices.Then,the thresholds of cotton vegetation and non-vegetation pixels were established based on the vegetation index threshold method which combines support vector machine classification and vegetation index.Finally,the accuracy difference in vegetation information extraction between the newly constructed and several published indices was compared.The results show that the accuracy of the information extracted by TRVI is higher than that of subdivision index of other visible light(FVC extraction precision in the first bud stage of cotton:R2=0.832,RMSE=2.307,nRMSE=4.405%;FVC extraction precision in the bud stage of cotton:R2=0.981,RMSE=1.393,nRMSE=1.984%;FVC extraction precision in the flowering stage of cotton:R2=0.893,RMSE=2.101,nRMSE=2.422%;FVC extraction precision in the boll stage of cotton:R2=0.958,RMSE=1.850,nRMSE=2.050%).
