The spring flood of 2009 in the Red River Valley was exacerbated with severe ice breakup and ice jamming. To assist ice jam mitigation by cutting and breaking up the river ice cover before the flood season and to supp...The spring flood of 2009 in the Red River Valley was exacerbated with severe ice breakup and ice jamming. To assist ice jam mitigation by cutting and breaking up the river ice cover before the flood season and to support the operation of the Red River Floodway, Manitoba Water Stewardship is striving to model the occurrence of ice breakup and simulate the behaviour of ice jamming along the river. An important parameter in ice breakup forecasting is the ice thickness. RADARSAT-2 standard satellite images were collected along the course of the Red River in Manitoba during the 2009-2010 winter to help determine ice thicknesses along the river. Standard images can have transmit-receive polarizations in the horizontal-horizontal (HH) or horizontal-vertical (HV) configurations. Ice thickness measurements were taken in the field during the same time frame when the satellite passed over the Red River Valley. Good correlations were obtained between the HH-backscatter readings and the surveyed ice thicknesses. HV-backscatter readings correlate better with fresh snow depth measurements. Additionally, using same sensor incident angle and flight geometry allows ice thickening rate behavior over the course of the winter to be determined.展开更多
Results of investigation of X-ray diffraction, infrared and optical spectra of powders of the ruthenium dioxide, lead-silicate glass as well as their mixture before and after sintering are reported. Sintering conditio...Results of investigation of X-ray diffraction, infrared and optical spectra of powders of the ruthenium dioxide, lead-silicate glass as well as their mixture before and after sintering are reported. Sintering conditions typical for thick film resistors were used. Intensity of main lines of RuO2 in X-ray diffraction patterns of sintered mixtures decreases and they slightly shift towards small angles. No new reflexes appear in these patterns. Absorbance of RuO2 in the range of 2.5-100 μm is proportional to and featureless. Infrared spectrum of lead-silicate glass has absorption bands of [SiO4]4- tetrahedra and Pb-O bonds only. Optical spectrum of RuO2 has wide absorption bands at 950 and 370 nm. Spectra of the mixture of RuO2 and glass powders before and after sintering are different indicating that there is interaction between them during the sintering process. Concentration of free charge carriers estimated from the optical spectra is about 1021 cm-3.展开更多
The influence of an ultrathin 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） fluorescent dye layer at donor/acceptor heterojunction on the performance of small-molecule o...The influence of an ultrathin 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） fluorescent dye layer at donor/acceptor heterojunction on the performance of small-molecule organic photovoltaic （OPV） cell is studied. The structure of OPV cell is of indium-tin oxide （ITO）/copper phthalocyanine （CuPc）/DCJTB/fullerene （C60）/bathophenantbroline （Bphen）/Ag. The results show that open circuit voltage （Voc） increases to 0.57 V as the film thickness of DCJTB layer increases from 0.2 to 2.0 nm. By using an equivalent circuit model, the enhancement of VOC is found to be attributed to the reduced reverse saturation current density （Js） which is due to the lower highest occupied molecular orbital （HOMO） level in DCJTB than that in CuPc. Also, the short circuit current density （JSC） is affected when the DCJTB layer becomes thicker, resulting from the high series resistance RsA due to the low charge carrier mobility of fluorescent red dye.展开更多
目的:系统评价低能量红光对于近视儿童脉络膜厚度(ChT)和等效球镜度(SE)及眼轴长度(AL)的影响。方法:通过检索Pubmed、Embase、Cochrane Library、Web of Science、中国知网、万方、维普网及中国生物医学文献数据库共8个数据库,从建库至...目的:系统评价低能量红光对于近视儿童脉络膜厚度(ChT)和等效球镜度(SE)及眼轴长度(AL)的影响。方法:通过检索Pubmed、Embase、Cochrane Library、Web of Science、中国知网、万方、维普网及中国生物医学文献数据库共8个数据库,从建库至2023-01期间所有关于低能量红光干预近视发展的随机对照试验,红光干预作为试验组,仅配戴单焦眼镜作为对照组。按照Cochrane手册要求进行文献质量及偏倚风险评价。Meta分析由Revman5.4软件完成。结果:共计纳入8篇有关低能量红光干预近视发展的随机对照试验研究。用于分析ChT变化的样本量为红光组407眼,对照组425眼;用于分析SE变化差值的样本量为红光组490眼,对照组518眼;纳入AL分析的样本量为红光组518眼,对照组539眼。红光组与对照组ChT、SE、AL比较均有差异(ChT:WMD=37.81,95%CI:21.55~54.07,P<0.001;SE:WMD=0.58,95%CI:0.46~0.71,P<0.001;AL:WMD=-0.31,95%CI:-0.39~-0.24,P<0.001)。结论:特定的红光有助于促进ChT而抑制SE及AL增加,但其远期效果及副作用尚不清楚,上述结论还需要更多大样本的随机对照研究进一步明确。展开更多
文摘The spring flood of 2009 in the Red River Valley was exacerbated with severe ice breakup and ice jamming. To assist ice jam mitigation by cutting and breaking up the river ice cover before the flood season and to support the operation of the Red River Floodway, Manitoba Water Stewardship is striving to model the occurrence of ice breakup and simulate the behaviour of ice jamming along the river. An important parameter in ice breakup forecasting is the ice thickness. RADARSAT-2 standard satellite images were collected along the course of the Red River in Manitoba during the 2009-2010 winter to help determine ice thicknesses along the river. Standard images can have transmit-receive polarizations in the horizontal-horizontal (HH) or horizontal-vertical (HV) configurations. Ice thickness measurements were taken in the field during the same time frame when the satellite passed over the Red River Valley. Good correlations were obtained between the HH-backscatter readings and the surveyed ice thicknesses. HV-backscatter readings correlate better with fresh snow depth measurements. Additionally, using same sensor incident angle and flight geometry allows ice thickening rate behavior over the course of the winter to be determined.
文摘Results of investigation of X-ray diffraction, infrared and optical spectra of powders of the ruthenium dioxide, lead-silicate glass as well as their mixture before and after sintering are reported. Sintering conditions typical for thick film resistors were used. Intensity of main lines of RuO2 in X-ray diffraction patterns of sintered mixtures decreases and they slightly shift towards small angles. No new reflexes appear in these patterns. Absorbance of RuO2 in the range of 2.5-100 μm is proportional to and featureless. Infrared spectrum of lead-silicate glass has absorption bands of [SiO4]4- tetrahedra and Pb-O bonds only. Optical spectrum of RuO2 has wide absorption bands at 950 and 370 nm. Spectra of the mixture of RuO2 and glass powders before and after sintering are different indicating that there is interaction between them during the sintering process. Concentration of free charge carriers estimated from the optical spectra is about 1021 cm-3.
基金Project partially supported by the National Natural Science Foundation of China(NNSFC)(Grant Nos.60736005 and 60425101-1)the Foundation for Innovative Research Groups of the NNSFC(Grant No.60721001)+3 种基金the Research Fund for the Dectoral Program of Higher Education(RFDP)(Grant No.20090185110020)the Program for New Century Excellent Talents in University,China(Grant No.NCET-06-0812)the Scientific Research Foundation for Returned Overseas Chinese Scholars,State Education Ministry(Grant No.GGRYJJ08-05)the Young Excellence Project of Sichuan Province,China(Grant No.09ZQ026-074)
文摘The influence of an ultrathin 4-（dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） fluorescent dye layer at donor/acceptor heterojunction on the performance of small-molecule organic photovoltaic （OPV） cell is studied. The structure of OPV cell is of indium-tin oxide （ITO）/copper phthalocyanine （CuPc）/DCJTB/fullerene （C60）/bathophenantbroline （Bphen）/Ag. The results show that open circuit voltage （Voc） increases to 0.57 V as the film thickness of DCJTB layer increases from 0.2 to 2.0 nm. By using an equivalent circuit model, the enhancement of VOC is found to be attributed to the reduced reverse saturation current density （Js） which is due to the lower highest occupied molecular orbital （HOMO） level in DCJTB than that in CuPc. Also, the short circuit current density （JSC） is affected when the DCJTB layer becomes thicker, resulting from the high series resistance RsA due to the low charge carrier mobility of fluorescent red dye.
文摘目的:系统评价低能量红光对于近视儿童脉络膜厚度(ChT)和等效球镜度(SE)及眼轴长度(AL)的影响。方法:通过检索Pubmed、Embase、Cochrane Library、Web of Science、中国知网、万方、维普网及中国生物医学文献数据库共8个数据库,从建库至2023-01期间所有关于低能量红光干预近视发展的随机对照试验,红光干预作为试验组,仅配戴单焦眼镜作为对照组。按照Cochrane手册要求进行文献质量及偏倚风险评价。Meta分析由Revman5.4软件完成。结果:共计纳入8篇有关低能量红光干预近视发展的随机对照试验研究。用于分析ChT变化的样本量为红光组407眼,对照组425眼;用于分析SE变化差值的样本量为红光组490眼,对照组518眼;纳入AL分析的样本量为红光组518眼,对照组539眼。红光组与对照组ChT、SE、AL比较均有差异(ChT:WMD=37.81,95%CI:21.55~54.07,P<0.001;SE:WMD=0.58,95%CI:0.46~0.71,P<0.001;AL:WMD=-0.31,95%CI:-0.39~-0.24,P<0.001)。结论:特定的红光有助于促进ChT而抑制SE及AL增加,但其远期效果及副作用尚不清楚,上述结论还需要更多大样本的随机对照研究进一步明确。
