Quantum technology establishes a foundation for secure communication via quantum key distribution (QKD). In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. I...Quantum technology establishes a foundation for secure communication via quantum key distribution (QKD). In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satellites with different sizes, such as space stations. Here we report an experimental demonstration of space-to-ground QKD using a small-sized payload, from Tiangong-2 space lab to Nanshan ground station. The 57.9-kg payload integrates a tracking system, a QKD transmitter along with modules for synchronization, and a laser communication transmitter. In the space lab, a 50MHz vacuum+weak decoy-state optical source is sent through a reflective telescope with an aperture of 200mm. On the ground station, a telescope with an aperture of 1200mm collects the signal photons. A stable and high-transmittance communication channel is set up with a high-precision bidirectional tracking system, a polarization compensation module, and a synchronization system. When the quantum link is successfully established, we obtain a key rate over 100bps with a communication distance up to 719km. Together with our recent development of QKD in daylight, the present demonstration paves the way towards a practical satellite-constellation-based global quantum secure network with small-sized QKD payloads.展开更多
Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,f...Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,for realizing UV-visible-NIR light driven dehydrogenation of benzyl alcohol(BA)into benzaldehydes(BAD)and H_(2),a novel localized surface plasmon resonance(LSPR)enhanced S-scheme heterojunction was designed by combining noble-metal-free plasmon MoO_(3-x) as oxidation semiconductor and Zn_(0.1)Cd_(0.9)S as reduction semiconductor.The photoredox system of Zn_(0.1)Cd_(0.9)S/MoO_(3-x) displayed an unconventional reaction model,in which the BA served as both electron donor and acceptor.The S-scheme charge transfer mechanism induced by the formed internal electric field enhanced the redox ability of charge carriers thermodynamically and boosted charge separation kinetically.Moreover,due to the LSPR effect of MoO_(3-x) nanosheets,Zn_(0.1)Cd_(0.9)S/MoO_(3-x) photocatalysts exhibited strong absorption in the region of full solar spectrum.Therefore,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite generated H_(2) and BAD simultaneously via selective oxidation of BA with high production(34.38 and 33.83 mmol×g^(–1) for H_(2) and BAD,respectively)upon full solar illumination.Even under NIR light irradiation,the H_(2) production rate could up to 94.5 mmol×g^(–1)×h^(–1).In addition,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite displayed effective photocatalytic H_(2) evolution rate up to 149.2 mmol×g^(–1)×h^(–1) from water,which was approximate 6 times that of pure Zn_(0.1)Cd_(0.9)S.This work provides a reference for rational design of plasmonic S-scheme heterojunction photocatalysts for coproduction of high-value chemicals and solar fuel production.展开更多
Dear Editor,Compared with traditional technologies affecting gene expression,changing DNA sequences of target genes is one of the most outstanding characters of CRISPR(Clustered Regularly Interspaced Short Palindromic...Dear Editor,Compared with traditional technologies affecting gene expression,changing DNA sequences of target genes is one of the most outstanding characters of CRISPR(Clustered Regularly Interspaced Short Palindromic Repeats).Single-guide RNAs(sgRNAs)guiding endonuclease Cas to target sites is a crucial step of CRISPR-Cas system for changing DNA sequences.An ideal sgRNA should only bind to the target gene.However,similar sequences of non-target sites can also be recognized leading to off-target effects[1].展开更多
Commercial varieties of upland cotton(Gossypium hirsutum)have undergone extensive breeding for agronomic traits,such as fiber quality,disease resistance,and yield.Cotton breeding programs have widely used Chinese upla...Commercial varieties of upland cotton(Gossypium hirsutum)have undergone extensive breeding for agronomic traits,such as fiber quality,disease resistance,and yield.Cotton breeding programs have widely used Chinese upland cotton source germplasm(CUCSG)with excellent agronomic traits.A better understanding of the genetic diversity and genomic characteristics of these accessions could accelerate the identification of desirable alleles.Here,we analyzed 10,522 high-quality singlenucleotide polymorphisms(SNP)with the CottonSNP63 K microarray in 137 cotton accessions(including 12 hybrids of upland cotton).These data were used to investigate the genetic diversity,population structure,and genomic characteristics of each population and the contribution of these loci to heterosis.Three subgroups were identified,in agreement with their knownpedigrees,geographical distributions,and times since introduction.For each group,we identified lineagespecific genomic divergence regions,which potentially harbor key alleles that determine the characteristics of each group,such as early maturity-related loci.Investigation of the distribution of heterozygous loci,among 12 commercial cotton hybrids,revealed a potential role for these regions in heterosis.Our study provides insight into the population structure of upland cotton germplasm.Furthermore,the overlap between lineagespecific regions and heterozygous loci,in the high-yield hybrids,suggests a role for these regions in cotton heterosis.展开更多
Flowering time(FTi)is a major factor determining how quickly cotton plants reach maturity.Early maturity greatly affects lint yield and fiber quality and is crucial for mechanical harvesting of cotton in northwestern ...Flowering time(FTi)is a major factor determining how quickly cotton plants reach maturity.Early maturity greatly affects lint yield and fiber quality and is crucial for mechanical harvesting of cotton in northwestern China.Yet,few quantitative trait loci(QTLs)or genes regulating early maturity have been reported in cotton,and the underlying regulatory mechanisms are largely unknown.In this study,we characterized 152,68,and 101 loci that were significantly associated with the three key early maturity traits—FTi,flower and boll period(FBP)and whole growth period(WGP),respectively,via four genome-wide association study methods in upland cotton(Gossypium hirsutum).We focused on one major early maturity-related genomic region containing three single nucleotide polymorphisms on chromosome D03,and determined that GhAP1-D3,a gene homologous to Arabidopsis thaliana APETALA1(AP1),is the causal locus in this region.Transgenic plants overexpressing GhAP1-D3 showed significantly early flowering and early maturity without penalties for yield and fiber quality compared to wild-type(WT)plants.By contrast,the mutant lines of GhAP1-D3 generated by genome editing displayed markedly later flowering than the WT.GhAP1-D3 interacted with GhSOC1(SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1),a pivotal regulator of FTi,both in vitro and in vivo.Changes in GhAP1-D3 transcript levels clearly affected the expression of multiple key flowering regulatory genes.Additionally,DNA hypomethylation and high levels of H3K9ac affected strong expression of GhAP1-D3 in early-maturing cotton cultivars.We propose that epigenetic modifications modulate GhAP1-D3 expression to positively regulate FTi in cotton through interaction of the encoded GhAP1 with GhSOC1 and affecting the transcription of multiple flowering-related genes.These findings may also lay a foundation for breeding early-maturing cotton varieties in the future.展开更多
With the development of controllable quantum systems,fast and practical characterization of multi-qubit gates has become essential for building high-fidelity quantum computing devices.The usual way to fulfill this req...With the development of controllable quantum systems,fast and practical characterization of multi-qubit gates has become essential for building high-fidelity quantum computing devices.The usual way to fulfill this requirement via randomized benchmarking demands complicated implementation of numerous multi-qubit twirling gates.How to efficiently and reliably estimate the fidelity of a quantum process remains an open problem.This work thus proposes a character-cycle benchmarking protocol and a character-average benchmarking protocol using only local twirling gates to estimate the process fidelity of an individual multi-qubit operation.Our protocols were able to characterize a large class of quantum gates including and beyond the Clifford group via the local gauge transformation,which forms a universal gate set for quantum computing.We demonstrated numerically our protocols for a non-Clifford gate—controlled-(T X)and a Clifford gate—five-qubit quantum errorcorrecting encoding circuit.The numerical results show that our protocols can efficiently and reliably characterize the gate process fidelities.Compared with the cross-entropy benchmarking,the simulation results show that the character-average benchmarking achieves three orders of magnitude improvements in terms of sampling complexity.展开更多
Dear Editor,Sources of genetic variations in genomes include small-scale sources(such as single-nucleotide polymorphisms(SNPs),insertions/deletions(InDels),and simple sequence repeats and larger-scale structural varia...Dear Editor,Sources of genetic variations in genomes include small-scale sources(such as single-nucleotide polymorphisms(SNPs),insertions/deletions(InDels),and simple sequence repeats and larger-scale structural variations(mainly presence-absence variants(PAVs))and copy number variants).PAVs are sequences that are either inserted or missing in genomes in comparison with a reference sequence or genome.PAVs can have a much longer sequence than SNPs and InDels,as illustrated in the human genome(Conrad et al.,2010).PAVs are important genomic structural variations that can directly affect genomic structure and key functional genes in the genome(Kumar et al.,2007).Moreover,the use of PAVs for studying quantitative traits has been valuable(Lam et al.,2010).展开更多
基金Supported by China Manned Space Program,Technology and Engineering Center for Space Utilization Chinese Academy of Sciences,Chinese Academy of Sciencesthe National Natural Science Foundation of China
文摘Quantum technology establishes a foundation for secure communication via quantum key distribution (QKD). In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satellites with different sizes, such as space stations. Here we report an experimental demonstration of space-to-ground QKD using a small-sized payload, from Tiangong-2 space lab to Nanshan ground station. The 57.9-kg payload integrates a tracking system, a QKD transmitter along with modules for synchronization, and a laser communication transmitter. In the space lab, a 50MHz vacuum+weak decoy-state optical source is sent through a reflective telescope with an aperture of 200mm. On the ground station, a telescope with an aperture of 1200mm collects the signal photons. A stable and high-transmittance communication channel is set up with a high-precision bidirectional tracking system, a polarization compensation module, and a synchronization system. When the quantum link is successfully established, we obtain a key rate over 100bps with a communication distance up to 719km. Together with our recent development of QKD in daylight, the present demonstration paves the way towards a practical satellite-constellation-based global quantum secure network with small-sized QKD payloads.
文摘Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,for realizing UV-visible-NIR light driven dehydrogenation of benzyl alcohol(BA)into benzaldehydes(BAD)and H_(2),a novel localized surface plasmon resonance(LSPR)enhanced S-scheme heterojunction was designed by combining noble-metal-free plasmon MoO_(3-x) as oxidation semiconductor and Zn_(0.1)Cd_(0.9)S as reduction semiconductor.The photoredox system of Zn_(0.1)Cd_(0.9)S/MoO_(3-x) displayed an unconventional reaction model,in which the BA served as both electron donor and acceptor.The S-scheme charge transfer mechanism induced by the formed internal electric field enhanced the redox ability of charge carriers thermodynamically and boosted charge separation kinetically.Moreover,due to the LSPR effect of MoO_(3-x) nanosheets,Zn_(0.1)Cd_(0.9)S/MoO_(3-x) photocatalysts exhibited strong absorption in the region of full solar spectrum.Therefore,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite generated H_(2) and BAD simultaneously via selective oxidation of BA with high production(34.38 and 33.83 mmol×g^(–1) for H_(2) and BAD,respectively)upon full solar illumination.Even under NIR light irradiation,the H_(2) production rate could up to 94.5 mmol×g^(–1)×h^(–1).In addition,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite displayed effective photocatalytic H_(2) evolution rate up to 149.2 mmol×g^(–1)×h^(–1) from water,which was approximate 6 times that of pure Zn_(0.1)Cd_(0.9)S.This work provides a reference for rational design of plasmonic S-scheme heterojunction photocatalysts for coproduction of high-value chemicals and solar fuel production.
基金This work was supported by National Natural Science Foundation of China(Grant No.32100501)Shenzhen Science and Technology Program(Grant No.RCBS20210609103819020)J.Z.was funded by the Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(2021C02070-1).
文摘Dear Editor,Compared with traditional technologies affecting gene expression,changing DNA sequences of target genes is one of the most outstanding characters of CRISPR(Clustered Regularly Interspaced Short Palindromic Repeats).Single-guide RNAs(sgRNAs)guiding endonuclease Cas to target sites is a crucial step of CRISPR-Cas system for changing DNA sequences.An ideal sgRNA should only bind to the target gene.However,similar sequences of non-target sites can also be recognized leading to off-target effects[1].
基金supported by grants from the National Key Research and Development Program of China (2017YFD0102000 and 2016YFD0100306)the National Natural Science Foundation of China (31301365)
文摘Commercial varieties of upland cotton(Gossypium hirsutum)have undergone extensive breeding for agronomic traits,such as fiber quality,disease resistance,and yield.Cotton breeding programs have widely used Chinese upland cotton source germplasm(CUCSG)with excellent agronomic traits.A better understanding of the genetic diversity and genomic characteristics of these accessions could accelerate the identification of desirable alleles.Here,we analyzed 10,522 high-quality singlenucleotide polymorphisms(SNP)with the CottonSNP63 K microarray in 137 cotton accessions(including 12 hybrids of upland cotton).These data were used to investigate the genetic diversity,population structure,and genomic characteristics of each population and the contribution of these loci to heterosis.Three subgroups were identified,in agreement with their knownpedigrees,geographical distributions,and times since introduction.For each group,we identified lineagespecific genomic divergence regions,which potentially harbor key alleles that determine the characteristics of each group,such as early maturity-related loci.Investigation of the distribution of heterozygous loci,among 12 commercial cotton hybrids,revealed a potential role for these regions in heterosis.Our study provides insight into the population structure of upland cotton germplasm.Furthermore,the overlap between lineagespecific regions and heterozygous loci,in the high-yield hybrids,suggests a role for these regions in cotton heterosis.
基金funded by the National Natural Science Foundation of China(31971986 and 32260478)the Education Technology Innovation Project of Gansu Province(2022QB-076)+2 种基金the Gansu Province Science and Technology Program(20JR10RA520)the Biological Breeding program of Gansu Academy of Agricultural Sciences(2022GAAS04)the Tianshan talent plan of Xinjiang Autonomous Region(2021)。
文摘Flowering time(FTi)is a major factor determining how quickly cotton plants reach maturity.Early maturity greatly affects lint yield and fiber quality and is crucial for mechanical harvesting of cotton in northwestern China.Yet,few quantitative trait loci(QTLs)or genes regulating early maturity have been reported in cotton,and the underlying regulatory mechanisms are largely unknown.In this study,we characterized 152,68,and 101 loci that were significantly associated with the three key early maturity traits—FTi,flower and boll period(FBP)and whole growth period(WGP),respectively,via four genome-wide association study methods in upland cotton(Gossypium hirsutum).We focused on one major early maturity-related genomic region containing three single nucleotide polymorphisms on chromosome D03,and determined that GhAP1-D3,a gene homologous to Arabidopsis thaliana APETALA1(AP1),is the causal locus in this region.Transgenic plants overexpressing GhAP1-D3 showed significantly early flowering and early maturity without penalties for yield and fiber quality compared to wild-type(WT)plants.By contrast,the mutant lines of GhAP1-D3 generated by genome editing displayed markedly later flowering than the WT.GhAP1-D3 interacted with GhSOC1(SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1),a pivotal regulator of FTi,both in vitro and in vivo.Changes in GhAP1-D3 transcript levels clearly affected the expression of multiple key flowering regulatory genes.Additionally,DNA hypomethylation and high levels of H3K9ac affected strong expression of GhAP1-D3 in early-maturing cotton cultivars.We propose that epigenetic modifications modulate GhAP1-D3 expression to positively regulate FTi in cotton through interaction of the encoded GhAP1 with GhSOC1 and affecting the transcription of multiple flowering-related genes.These findings may also lay a foundation for breeding early-maturing cotton varieties in the future.
基金National Natural Science Foundation of China(11875173,12174216)National Key Research and Development Program of China(2019QY0702,2017YFA0303903)。
文摘With the development of controllable quantum systems,fast and practical characterization of multi-qubit gates has become essential for building high-fidelity quantum computing devices.The usual way to fulfill this requirement via randomized benchmarking demands complicated implementation of numerous multi-qubit twirling gates.How to efficiently and reliably estimate the fidelity of a quantum process remains an open problem.This work thus proposes a character-cycle benchmarking protocol and a character-average benchmarking protocol using only local twirling gates to estimate the process fidelity of an individual multi-qubit operation.Our protocols were able to characterize a large class of quantum gates including and beyond the Clifford group via the local gauge transformation,which forms a universal gate set for quantum computing.We demonstrated numerically our protocols for a non-Clifford gate—controlled-(T X)and a Clifford gate—five-qubit quantum errorcorrecting encoding circuit.The numerical results show that our protocols can efficiently and reliably characterize the gate process fidelities.Compared with the cross-entropy benchmarking,the simulation results show that the character-average benchmarking achieves three orders of magnitude improvements in terms of sampling complexity.
基金Supported by the National Key Research and Development Program of China (2016YFD0100300)the National Natural Science Foundation of China (31600223)+4 种基金the Natural Science Basic Research Plan in Shaanxi Province (2019JQ-062)the Shaanxi Youth Entrusted Talents Program (20190205)the Shaanxi Postdoctoral Project (2018BSHYDZZ76)the National Natural Science Foundation of China (31872175)and the State Key Laboratory of Cotton Biology Open Fund (CB2018A07, CB2019A03, and 2019A09).
文摘Dear Editor,Sources of genetic variations in genomes include small-scale sources(such as single-nucleotide polymorphisms(SNPs),insertions/deletions(InDels),and simple sequence repeats and larger-scale structural variations(mainly presence-absence variants(PAVs))and copy number variants).PAVs are sequences that are either inserted or missing in genomes in comparison with a reference sequence or genome.PAVs can have a much longer sequence than SNPs and InDels,as illustrated in the human genome(Conrad et al.,2010).PAVs are important genomic structural variations that can directly affect genomic structure and key functional genes in the genome(Kumar et al.,2007).Moreover,the use of PAVs for studying quantitative traits has been valuable(Lam et al.,2010).