While three-dimensional perovskites have high defect tolerance and an adjustable bandgap,their charges tend to be free rather than forming excitons,making them unsuitable for use in efficient light-emitting diodes(LED...While three-dimensional perovskites have high defect tolerance and an adjustable bandgap,their charges tend to be free rather than forming excitons,making them unsuitable for use in efficient light-emitting diodes(LEDs).Rather,quasi-two-dimensional(Q-2D)perovskites offer high photoluminescence quantum yield along with the advantages of bulk perovskites,making them ideal for high-performance LEDs.In Q-2D perovskites,the structure(which includes factors like crystal orientation,phase distribution,and layer thickness)directly influences how excitons and charge carriers behave within the material.Growth control techniques,such as varying the synthesis conditions or employing methods,allow for fine-tuning the structural characteristics of these materials,which in turn affect exciton dynamics and charge transport.This review starts with a description of the basic properties of Q-2D perovskites,examines crystal growth in solution,explains how structure affects energy transfer behavior,and concludes with future directions for Q-2D perovskite LEDs.By understanding and optimizing the structure-dependent behavior,researchers can better control exciton dynamics and charge transport,which are crucial for enhancing the performance of optoelectronic devices like solar cells and LEDs.展开更多
Sensitizing molecular triplets by colloidal nanocrystals via triplet energy transfer is important for applications such as upconversion or organic synthesis.Typically two step triplet energy transfer(TET)are included ...Sensitizing molecular triplets by colloidal nanocrystals via triplet energy transfer is important for applications such as upconversion or organic synthesis.Typically two step triplet energy transfer(TET)are included in these applications:firstly the triplet energy stored in nanocrystals are extracted into surface ligands,and then the ligands further transfer triplet energy into molecules in bulk solution.Here we report one-step TET application from CsPbBr_(3)perovskite nanocrystals(NCs)to surface-anchored metalloporphyrin derivative molecules(MP).Compared to conventional two-step TET,the one-step TET mechanism possess lower energy loss and higher TET efficiency which is more generally implementable.In this scheme,photoexcitation of CsPbBr_(3)NCs leads to the sensitization of MP ligands triplets which efficiently emit phosphorescence.The enhanced light absorption of MP ligands and down-shifted photon emission can be useful in devices such as luminescent solar concentrators.展开更多
The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improv...The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improved algorithmal expressions for strap down attitude ut ilizing the angular increment output by the laser gyro from the last two and cur rent updating periods according to the number of gyro samples, and analyses the algorithm error in the classical coning motion. Compared with the conventional algorithms, simulational results show that this improved algorithm has higher precision. A new way to improve the rotation vector algorithms is provided.展开更多
[Objective] The paper aims to explore the influences of source sink change of wheat at different densities on wheat yield.[Method] 225 （D1） and 320 plant/m2（D2） were adopted,then cutting flag leaf （L1）,the secon...[Objective] The paper aims to explore the influences of source sink change of wheat at different densities on wheat yield.[Method] 225 （D1） and 320 plant/m2（D2） were adopted,then cutting flag leaf （L1）,the second last leaf （L2）,removing upper part of spike （L3） and controlling （CK） were used to conduct field experiment.[Result] The results showed that both of the two densities of wheat＇s 1 000-grain weight and grain filling rate after anthesis in a decreasing order of L3〉CK〉L2〉L1,and the grain weight per spike and dry matter amount translated after anthesis turned to be CK〉L2〉L1 〉L3.[Conclusion].Both of leaf-cutting and spikelet removing decreased the grain weight per spike and dry matter amount translated after anthesis.Removing upper part of spike increased wheat＇s 1 000-grain weight.But the decreasing of the sink and dry matter amount translated contributed to the decreasing of the yield of wheat.展开更多
The electrical resistivity of NZ30K-Mg alloy was measured at different heating rates during continuous heating to stud the precipitation kinetics.Two kinds of metastable phases,β＂ and β＇,formed during the heating....The electrical resistivity of NZ30K-Mg alloy was measured at different heating rates during continuous heating to stud the precipitation kinetics.Two kinds of metastable phases,β＂ and β＇,formed during the heating.Kissinger method and differentia isoconversional method were employed to assess the precipitation kinetic parameters of NZ30K-Mg alloy,activation energy Eα an pre-exponential factor A＇α.The fraction of transformation（α） and the precipitation sequence in NZ30K-Mg alloy were determinec Continuous heating transformation（CHT） and isothermal heating transformation（IHT） diagrams were further obtained for guidin the aging of NZ30K-Mg alloy.The analysis shows that the precipitation kinetic parameters of NZ30K-Mg alloy can be obtaine accurately using isoconversional method.展开更多
[Objective] The study was to investigate roles of Brassica napus EINB in （ BnEIN3 ） resistance to Sclerotinia sclerotiorum. [ Methods] Genomic PCR and RT-PCR were carded out to isolate genomic DNA and cDNA sequences...[Objective] The study was to investigate roles of Brassica napus EINB in （ BnEIN3 ） resistance to Sclerotinia sclerotiorum. [ Methods] Genomic PCR and RT-PCR were carded out to isolate genomic DNA and cDNA sequences of BnEIN3 from oilseed rape, based on the highly conserved region of EIN3 gene from Arabidopsis thaliana and the homologous sequences of oilseed rape ESTs. Expression levels of BnEIN3 were detected in three varieties of oilseed rape inoculated with S. sclerotiorum by real-time quantitative PCR.[Results] A 1 947 bp DNA fragment was obtained from oilseed rape. The fragment shared 82% identity to A. thaliana EIIV3, encoded 614 amino acids containing an EIN3 domain, and was named as BnEIN3. Real-time PCR results showed that expression patterns of BnEIN3 were drastically different in different varieties. In highly resistant oilseed rape variety D083, BnEIN3 expression level was significantly increased 72 h after S. sclerotiorum inoculation whereas in middle resistant and susceptible varieties Zhongshuang 9 and 84039, BnEIN3 expression was suppressed. [ Conclusion ] BnEIIV3 may play an important role in oilseed rape resistance to S. sclerotiorum.展开更多
文摘While three-dimensional perovskites have high defect tolerance and an adjustable bandgap,their charges tend to be free rather than forming excitons,making them unsuitable for use in efficient light-emitting diodes(LEDs).Rather,quasi-two-dimensional(Q-2D)perovskites offer high photoluminescence quantum yield along with the advantages of bulk perovskites,making them ideal for high-performance LEDs.In Q-2D perovskites,the structure(which includes factors like crystal orientation,phase distribution,and layer thickness)directly influences how excitons and charge carriers behave within the material.Growth control techniques,such as varying the synthesis conditions or employing methods,allow for fine-tuning the structural characteristics of these materials,which in turn affect exciton dynamics and charge transport.This review starts with a description of the basic properties of Q-2D perovskites,examines crystal growth in solution,explains how structure affects energy transfer behavior,and concludes with future directions for Q-2D perovskite LEDs.By understanding and optimizing the structure-dependent behavior,researchers can better control exciton dynamics and charge transport,which are crucial for enhancing the performance of optoelectronic devices like solar cells and LEDs.
基金This work is supported by the National Natural Science Foundation of China(No.21803070).
文摘Sensitizing molecular triplets by colloidal nanocrystals via triplet energy transfer is important for applications such as upconversion or organic synthesis.Typically two step triplet energy transfer(TET)are included in these applications:firstly the triplet energy stored in nanocrystals are extracted into surface ligands,and then the ligands further transfer triplet energy into molecules in bulk solution.Here we report one-step TET application from CsPbBr_(3)perovskite nanocrystals(NCs)to surface-anchored metalloporphyrin derivative molecules(MP).Compared to conventional two-step TET,the one-step TET mechanism possess lower energy loss and higher TET efficiency which is more generally implementable.In this scheme,photoexcitation of CsPbBr_(3)NCs leads to the sensitization of MP ligands triplets which efficiently emit phosphorescence.The enhanced light absorption of MP ligands and down-shifted photon emission can be useful in devices such as luminescent solar concentrators.
文摘The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improved algorithmal expressions for strap down attitude ut ilizing the angular increment output by the laser gyro from the last two and cur rent updating periods according to the number of gyro samples, and analyses the algorithm error in the classical coning motion. Compared with the conventional algorithms, simulational results show that this improved algorithm has higher precision. A new way to improve the rotation vector algorithms is provided.
基金Supported by Jiangsu High School Natural Science Fund(09KJB210004)Undergraduate Practice Innovation Project of Nanjing University of Information Science & Technology (09CX0025 )Educational Reform Project of Nanjing University of Information Science &Technology (09JY0036)~~
文摘[Objective] The paper aims to explore the influences of source sink change of wheat at different densities on wheat yield.[Method] 225 （D1） and 320 plant/m2（D2） were adopted,then cutting flag leaf （L1）,the second last leaf （L2）,removing upper part of spike （L3） and controlling （CK） were used to conduct field experiment.[Result] The results showed that both of the two densities of wheat＇s 1 000-grain weight and grain filling rate after anthesis in a decreasing order of L3〉CK〉L2〉L1,and the grain weight per spike and dry matter amount translated after anthesis turned to be CK〉L2〉L1 〉L3.[Conclusion].Both of leaf-cutting and spikelet removing decreased the grain weight per spike and dry matter amount translated after anthesis.Removing upper part of spike increased wheat＇s 1 000-grain weight.But the decreasing of the sink and dry matter amount translated contributed to the decreasing of the yield of wheat.
基金Project (2011ZX04014-052,2012ZX04012011) supported by CNC Machine Tools and Basic Manufacturing Equipment Technology Comments
文摘The electrical resistivity of NZ30K-Mg alloy was measured at different heating rates during continuous heating to stud the precipitation kinetics.Two kinds of metastable phases,β＂ and β＇,formed during the heating.Kissinger method and differentia isoconversional method were employed to assess the precipitation kinetic parameters of NZ30K-Mg alloy,activation energy Eα an pre-exponential factor A＇α.The fraction of transformation（α） and the precipitation sequence in NZ30K-Mg alloy were determinec Continuous heating transformation（CHT） and isothermal heating transformation（IHT） diagrams were further obtained for guidin the aging of NZ30K-Mg alloy.The analysis shows that the precipitation kinetic parameters of NZ30K-Mg alloy can be obtaine accurately using isoconversional method.
文摘[Objective] The study was to investigate roles of Brassica napus EINB in （ BnEIN3 ） resistance to Sclerotinia sclerotiorum. [ Methods] Genomic PCR and RT-PCR were carded out to isolate genomic DNA and cDNA sequences of BnEIN3 from oilseed rape, based on the highly conserved region of EIN3 gene from Arabidopsis thaliana and the homologous sequences of oilseed rape ESTs. Expression levels of BnEIN3 were detected in three varieties of oilseed rape inoculated with S. sclerotiorum by real-time quantitative PCR.[Results] A 1 947 bp DNA fragment was obtained from oilseed rape. The fragment shared 82% identity to A. thaliana EIIV3, encoded 614 amino acids containing an EIN3 domain, and was named as BnEIN3. Real-time PCR results showed that expression patterns of BnEIN3 were drastically different in different varieties. In highly resistant oilseed rape variety D083, BnEIN3 expression level was significantly increased 72 h after S. sclerotiorum inoculation whereas in middle resistant and susceptible varieties Zhongshuang 9 and 84039, BnEIN3 expression was suppressed. [ Conclusion ] BnEIIV3 may play an important role in oilseed rape resistance to S. sclerotiorum.
