Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extens...Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extensive attention due to their advantages of small size,high multiplexing efficiency,convenient mass production,and low cost.An RGB beam combiner based on directional couplers is designed,with a core-cladding relative refractive index difference of 0.75%.The RGB beam combiner is optimized from the perspective of parameter optimization.Using the beam propagation method(BPM),the relationship between the performance of the RGB beam combiner and individual parameters is studied,achieving preliminary optimization of the device’s performance.The key parameters of the RGB beam combiner are optimized using the entropy weight-technique for order preference by similarity to an ideal solution TOPSIS method,establishing the optimal parameter scheme and further improving the device’s performance indicators.The results show that after optimization,the multiplexing efficiencies for red,green,and blue lights,as well as the average multiplexing efficiency,reached 99.17%,99.76%,96.63%and 98.52%,respectively.The size of the RGB beam combiner is 4.768 mm×0.062 mm.展开更多
Based on the Overlapped Multiplexing Principle[12],a frequency domain OVFDM(Overlapped Frequency Domain Multiplexing) Coding is proposed.By the data weighted shift overlapped version of any band-limited Multiplexing T...Based on the Overlapped Multiplexing Principle[12],a frequency domain OVFDM(Overlapped Frequency Domain Multiplexing) Coding is proposed.By the data weighted shift overlapped version of any band-limited Multiplexing Transfer Function H(f) the coding gain and spectral efficiency are both achieved.The heavier the overlap of the data weighted Multiplexing Transfer Function H(f),the higher the coding gain and spectral efficiency as well as the closer the output to the optimum complex Gaussian distribution.The bit error probability performance is estimated.The time domain OVTDM(Overlapped Time Domain Multiplexing) Coding,the dual of OVFDM in time domain is incidentally proposed as well.Both theoretical analysis and testified simulations show that OVFDM(OVTDM) is suitable for high spectral efficiency application and its spectral efficiency is only roughly linear to SNR rather than the well-known logarithm to SNR.展开更多
In order to satisfy sending multi-channel navigation signals in one frequency for modern GNSS（Global Navigation Satellite System）, the principle of Interplex multiplexing were introduced. And the three-way multiplex...In order to satisfy sending multi-channel navigation signals in one frequency for modern GNSS（Global Navigation Satellite System）, the principle of Interplex multiplexing were introduced. And the three-way multiplexing structure and the four-way multiplexing method were also optimized. The Galileo E1 signal, as the example of Interplex reuse, was analyzed in detail. The power configuration of the multiplexing efficiency and the minimum of the multiplexing efficiency were obtained.展开更多
Most of the important agronomic traits in crop plants, such as yield, quality and stress response, are quantitative and jointly controlled by many genomic loci or major genes. Improving these complex traits depends on...Most of the important agronomic traits in crop plants, such as yield, quality and stress response, are quantitative and jointly controlled by many genomic loci or major genes. Improving these complex traits depends on the combination of beneficial alleles at the quantitative trait loci （QTLs）. However, the conventional cross breeding method is extremely time-consuming and laborious for pyramiding multiple QTLs. In certain cases, this approach might be technically difficult because of close linkage between genes separately responsible for desirable and undesirable traits.展开更多
Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9...Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.展开更多
Dear Editor,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants.The system is composed of a nuclease...Dear Editor,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants.The system is composed of a nuclease such as Cas9 or Cas12a and an engineered single-guide RNA(sgRNA)incorporating a target sequence(Li et al.,2019).A Cas9/sgRNA complex recognizes its target site in the genome,resulting in a mutation at that site.展开更多
基金Project(52175445)supported by the National Natural Science Foundation of ChinaProject(2022JJ30743)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(2023GK2024)supported by the Key Research and Development Program of Hunan Province,ChinaProject(2023ZZTS0391)supported by the Fundamental Research Funds for the Central Universities of China。
文摘Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extensive attention due to their advantages of small size,high multiplexing efficiency,convenient mass production,and low cost.An RGB beam combiner based on directional couplers is designed,with a core-cladding relative refractive index difference of 0.75%.The RGB beam combiner is optimized from the perspective of parameter optimization.Using the beam propagation method(BPM),the relationship between the performance of the RGB beam combiner and individual parameters is studied,achieving preliminary optimization of the device’s performance.The key parameters of the RGB beam combiner are optimized using the entropy weight-technique for order preference by similarity to an ideal solution TOPSIS method,establishing the optimal parameter scheme and further improving the device’s performance indicators.The results show that after optimization,the multiplexing efficiencies for red,green,and blue lights,as well as the average multiplexing efficiency,reached 99.17%,99.76%,96.63%and 98.52%,respectively.The size of the RGB beam combiner is 4.768 mm×0.062 mm.
基金The NNSF(National Nature Science Foundation)of China for their continuously long term support by key projects
文摘Based on the Overlapped Multiplexing Principle[12],a frequency domain OVFDM(Overlapped Frequency Domain Multiplexing) Coding is proposed.By the data weighted shift overlapped version of any band-limited Multiplexing Transfer Function H(f) the coding gain and spectral efficiency are both achieved.The heavier the overlap of the data weighted Multiplexing Transfer Function H(f),the higher the coding gain and spectral efficiency as well as the closer the output to the optimum complex Gaussian distribution.The bit error probability performance is estimated.The time domain OVTDM(Overlapped Time Domain Multiplexing) Coding,the dual of OVFDM in time domain is incidentally proposed as well.Both theoretical analysis and testified simulations show that OVFDM(OVTDM) is suitable for high spectral efficiency application and its spectral efficiency is only roughly linear to SNR rather than the well-known logarithm to SNR.
基金the key projects of education department in Sichuan Province under Grant No.14ZA0292 and the aviation science foundation project under Grand No.20100119004
文摘In order to satisfy sending multi-channel navigation signals in one frequency for modern GNSS（Global Navigation Satellite System）, the principle of Interplex multiplexing were introduced. And the three-way multiplexing structure and the four-way multiplexing method were also optimized. The Galileo E1 signal, as the example of Interplex reuse, was analyzed in detail. The power configuration of the multiplexing efficiency and the minimum of the multiplexing efficiency were obtained.
基金supported by Genetically Modified Breeding Major Projects(No.2016ZX08010-002-008)the National Natural Science Foundation of China(Nos.31501239 and 31401454)
文摘Most of the important agronomic traits in crop plants, such as yield, quality and stress response, are quantitative and jointly controlled by many genomic loci or major genes. Improving these complex traits depends on the combination of beneficial alleles at the quantitative trait loci （QTLs）. However, the conventional cross breeding method is extremely time-consuming and laborious for pyramiding multiple QTLs. In certain cases, this approach might be technically difficult because of close linkage between genes separately responsible for desirable and undesirable traits.
基金supported by the Beijing Scholars Program[BSP041]。
文摘Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.
基金grants from the National Natural Science Foundation of China (91435203 and 31991222)the Major Program of Guangdong Basic and Applied Basic Research (2019B030302006)。
文摘Dear Editor,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants.The system is composed of a nuclease such as Cas9 or Cas12a and an engineered single-guide RNA(sgRNA)incorporating a target sequence(Li et al.,2019).A Cas9/sgRNA complex recognizes its target site in the genome,resulting in a mutation at that site.
