Apomictic seed development is a complex process including formation of unreduced embryo sac,parthenogenetic embryo development from the egg cell,and endosperm formation either autonomously,or due to fertilization of p...Apomictic seed development is a complex process including formation of unreduced embryo sac,parthenogenetic embryo development from the egg cell,and endosperm formation either autonomously,or due to fertilization of polar nuclei by the sperm(under pseudogamous form of apomixis).In the latter case,an obstacle to the normal endosperm development is disturbance of maternal(m)-to-paternal(p)genomic ratio 2m:1p that occurs in the cases of pollination of unreduced embryo sac with haploid sperms.Usage of tetraploid pollinators can overcome this problem because in such crosses maternal-to-paternal genomic ratio is 4m:2p that provides formation of kernels with plump endosperm.Using tetraploid lines as pollen parents we observed formation of plump kernels on the ears and panicles of diploid maize and sorghum accessions.These kernels had hybrid endosperm and diploid maternal-type embryo or hybrid embryo with different ploidy level(2n,3n,4n).The frequencies of plump kernels on the ear ranged from 0.2-0.3%to 5.7-6.2%counting from the number of ovaries.Maternal-type plants were found in two maize lines,their frequency varying from 10.7 to 37.5%of the progeny plants.In CMS-lines of sorghum pollinated with tetraploid sorghum accessions,the frequency of plump kernels ranged from 0.6 to 14.0%counting from the number of ovaries;the frequency of maternal-type plants varied from 33.0 up to 96.1%.The hybrid nature of endosperm of the kernels that gave rise to maternal-type plants has been proved by marker gene expression and by SDS-electrophoresis of endosperm proteins.These data testify to variable modes of seed formation under diploid×tetraploid crosses in maize and sorghum both by amphi-and by apomixis.Therefore,usage of tetraploid pollinators might be a promising approach for isolation of apomixis in maize and sorghum accessions.展开更多
Comparison of seed setting rate,plant height and Cheng's morphological traits were made between the F_(2)progeny of indica-japonica hybrids,02428/Pei'ai 64 and Taichung 65/Teqing.There existed resemblance norm...Comparison of seed setting rate,plant height and Cheng's morphological traits were made between the F_(2)progeny of indica-japonica hybrids,02428/Pei'ai 64 and Taichung 65/Teqing.There existed resemblance normal distribution in plant height,and the distribution had no relationship with the seed setting rate and plant height in F_(1)progeny,suggesting that there were no gametic selection for the plant height in the F_(2)progeny of indica-japoniea hybrids.An average seed setting rate of the F_(2)was equal to the F_(1)populations in the recombination of 02428/Pei'ai 64 in which there was an excellent cross compatibility,but the remarkable increase in the seed setting rate from the F_(1)to F_(2)in Taichung 65/Teqing,indicating that gametic selection only took place in the indica-japonica crosses with low cross compatibility while null or little in the hybrids with high compatibility.There were many intermediate types among the leaf pubescence,color of hull at heading,and length of the first and second panicle internode,and these Cheng's morphological traits was distributed normally;there were also a little intermediate types in hull hairness and phenol reaction with bi-peak distribution;while length to width ratio of grain was inclined to the japonica types obviously showing a skewed distribution in the F_(2)population.Although Cheng's morphological traits in F_(2)populations had inconsistent distribution types,Cheng's morphological traits index showed normal distribution,which suggested that intermediate types,i.e.indicalinous or japonicalinous,were primary in F_(2)population.展开更多
Indica and japonica rices are two subspecies ofAsia cultivated rice.Their grain qualities exista significant difference.The objective of thispaper is to study the genetic control of qualitytraits in intersubspecies cr...Indica and japonica rices are two subspecies ofAsia cultivated rice.Their grain qualities exista significant difference.The objective of thispaper is to study the genetic control of qualitytraits in intersubspecies crosses of rice.In 1991,4 japonica varieties with widecompatibility,PC311,Zhenxiqiuguang,Lun-hui 422,and Ce 03 were crossed with 5 indicavarieties,3037,Zaoxiandang 18,IR36,Minghui 63,and Yangdao 4 according to NC(?)design.The 20 hybrids using japonica as ma-展开更多
Pure lines derived from multiple parents provide abundant variation for genetic study.However,efficient genetic analysis methods and user-friendly software are still lacking.In this study, we developed linkage analysi...Pure lines derived from multiple parents provide abundant variation for genetic study.However,efficient genetic analysis methods and user-friendly software are still lacking.In this study, we developed linkage analysis methods and integrated analysis software for pure-line populations derived from four-way and eight-way crosses.First, polymorphic markers are classified into different categories according to the number of identifiable alleles in the inbred parents.Expected genotypic probability is then derived for each pair of complete markers, and based on them a maximum likelihood estimate(MLE) of recombination frequency is calculated.An EM algorithm is proposed for calculating recombination frequencies in scenarios that at least one marker is incomplete.A linkage map can thus be constructed using estimated recombination frequencies.We describe a software package called GAPL for recombination frequency estimation and linkage map construction in multi-parental pure-line populations.Both simulation studies and results from a reported four-way cross recombinant inbred line population demonstrate that the proposed method and software can build more accurate linkage maps in shorter times than other published software packages.The GAPL software is freely available from www.isbreeding.net and can also be used for QTL mapping in multi-parental populations.展开更多
The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - d...The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - derived lines were chosen from each of the six crosses under both high-and low-fertility for use in this study. In 1995, the total 24 lines were tested in high, medium and low fertility sites with the same experimental design (CRB) to study the selcctoin effects of high and low - fertility. The results suggested that high- and low-fertility had different selection effects. High fertility was more effective for selecting lines, which had higher yield under high-fertility and lower yield under low-fertility; low-fertility was better for selecting lines, which had higher yield under low-fertility and lower yield under low-fertility, and high fertility was somewhat better than low fertility for selecting lines, which had higher yield under both high and low-fertility. It revealed that the lines selected from high-fertility had superior yield potential. The lines selected from high-fertility had shorter plant height, more nodes on main stem, fewer branches, higher seed-stem ratio. The reverse was true for the lines selected from low-fertility . The lodging-resistance of the lines selected from highfertility was greater than that of the lines from low-fertility. The soil fertility level of breeding nursery should be chosen according to the breeding objective.展开更多
The influence of the gap on the absorption performance of the conventional split ring resonator(SRR) absorber is investigated at microwave frequencies. Our simulated results reveal that the geometry of the square SRR ...The influence of the gap on the absorption performance of the conventional split ring resonator(SRR) absorber is investigated at microwave frequencies. Our simulated results reveal that the geometry of the square SRR can be equivalent to a Jerusalem cross(JC) resonator and its corresponding metamaterial absorber(MA) is changed to a JC absorber. The JC MA exhibits an experimental absorption peak of 99.1% at 8.72 GHz, which shows an excellent agreement with our simulated results. By simply assembling several JCs with slightly different geometric parameters next to each other into a unit cell, a perfect multi-band absorption can be effectively obtained. The experimental results show that the MA has four distinct and strong absorption peaks at 8.32 GHz, 9.8 GHz, 11.52 GHz and 13.24 GHz. Finally, the multi-reflection interference theory is introduced to interpret the absorption mechanism.展开更多
The narrow genetic base in potato (Solanum tuberosum L.) limits the progress in cultivar development.The rich diploid germplasm in the origin center of potato provide a unique resource for improvement of tetraploid po...The narrow genetic base in potato (Solanum tuberosum L.) limits the progress in cultivar development.The rich diploid germplasm in the origin center of potato provide a unique resource for improvement of tetraploid potatoes.Seven newly developed diploid hybrids with 2n pollen production,all of which have S. phureja background,were developed and evaluated for their value in potato breeding.They were crossed as male parnets to six tetraploid Solanum tuberosum cultivars,and seeds in large quantity from eleven crosses were obtained.Main agronomic traits,such as tuber yield,tuber number,mean tuber weight,tuber shape,eye depth,skin smoothness,flesh color,and specific gravity,were measured for 4x 2x tetraploid progenies in seedling generation,and their parents as well.All of the diploid hybrids had some merit for specific traits and the DH39 was more promising;high specific gravity trait in some diploid hybrids was successfully introgressed into tetroploid progenies via 4x 2x crosses.These diploid hybrids have potential value in potato breeding.展开更多
The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones pr...The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones primarily precipitate in the sample aged at 200℃for 1 h(T6-200℃/1h),while the Al_(2)Ca phases mainly precipitate in the sample aged at 275℃for 8 h(T6-275℃/8h).The T6-200℃/1h sample exhibits excellent creep resistance,with a steady-state creep rate one order of magnitude lower than that of the T6-275℃/8h sample.The abnormally high stress exponent(~8.2)observed in the T6-200℃/1h sample is associated with the power-law breakdown mechanism.TEM analysis illuminates that the creep mechanism for the T6-200℃/1h sample is cross-slip between basal and prismatic dislocations,while the T6-275℃/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb.Compared with the Al_(2)Ca phase,the dense G.P.zones effectively impede dislocation climb and glide during the creep process,demonstrating superior creep resistance of the T6-200℃/1h sample.展开更多
Mai Weitong,an illustrator and motion-graphic artist,based in London,the United Kingdom,has been drawing since she was a child,immersed in both Eastern and Western artistic environments.In 2017,after she graduated fro...Mai Weitong,an illustrator and motion-graphic artist,based in London,the United Kingdom,has been drawing since she was a child,immersed in both Eastern and Western artistic environments.In 2017,after she graduated from Camberwell College of Arts,in the UK,with a bachelor’s degree in illustration,Mai became a freelance illustrator,and she began collaborating with various publishers and advertising agencies to create book illustrations and promotional artwork.In her work,she has revitalized Eastern elements with contemporary illustrations.Through her illustrations,Mai creates bridges of cross-cultural communication,which she uses to help introduce talented Asian illustrators to international audiences.展开更多
To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.T...To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.展开更多
Hybridization remains an important method for breeding new poplar varieties.It results in significant variation in leaf phenotype among parents and offspring,and among offspring themselves.This study aimed to investig...Hybridization remains an important method for breeding new poplar varieties.It results in significant variation in leaf phenotype among parents and offspring,and among offspring themselves.This study aimed to investigate whether leaf shape variations were similar in offspring produced from reciprocal crosses.Specifically,two hybrid combinations were produced:the direct cross with Populus ussuriensis as the maternal parent and P.simonii×P.nigra as the paternal parent(HY53),and the reciprocal cross with P.simonii×P.nigra as the maternal parent and P.ussuriensis as the paternal parent(HY268).Using 3-month-old rooted cuttings from 40 clones(36 F1 hybrids and their parents)growing in a greenhouse,we measured and analyzed 14 leaf morphological traits to assess genetic variation and heterosis.The results showed HY53 clones generally exhibited greater average height than HY268 clones.Leaf phenotypes differed between the two hybrid combinations,with significant differences observed among parents and offspring for almost all traits,as revealed by analysis of variance(ANOVA).The phenotypic coefficient of variation was higher in HY268 clones.Additionally,leaf traits demonstrated high repeatability.Notably,some hybrid offspring exhibited positive or negative mid-parent heterosis,as well as over-parent heterosis for certain leaf phenotypes.The systematic cluster analysis further indicated distinct separation among HY268 clones.This research provides valuable materials for poplar breeding and offers insights into hybrid vigor in wood plants.The findings highlight the importance of reciprocal crossing in influencing leaf phenotype variation and heterosis,offering practical insights for future breeding strategies.展开更多
Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsit...Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsite,nearest neighbor,and next-nearest-neighbor Coulomb interactions,respectively.When the Fermi level lies in the flat band,the instability toward ferromagnetic(FM)order gives rise to a FM half-metal at sufficiently large onsite N.Intriguingly,at band filling n=17/24,the Fermi level crosses the van Hove singularity of the spin-minority bands of the half-metal.We show that,due to the unique geometry and sublattice interference on the kagomélattice at van Hove singularity,the inter-site Coulomb interactions V_(1) and V_(2)drive a real and an imaginary bond-ordered 2a_(0)×2a_(0) CDW instability,respectively.The FM loop current CDW with complex bond orders is a spin-polarized Chern insulator exhibiting the quantum anomalous Hall effect.The bond fluctuations are found to be substantially enhanced compared to the corresponding nonmagnetic kagomémetals at van Hove filling,providing a concrete model realization of the bond-ordered CDWs,including the FM loop current CDW,over the onsite charge density ordered states.When the spins are partially polarized at an intermediate N,we find that the interplay of CDW and magnetism enables the formation of real and complex bond-ordered CDWs,and the CDW transition is accompanied by a substantial enhancement in the ordered magnetic moments.These findings provide physical insights for the emergence of 2a_(0)×2a_(0) CDWs and their interplay with magnetism on the kagomélattice,and capture the essential physics observed experimentally in Fe Ge.展开更多
Wild peanut(Arachis)species are promising sources of disease resistance for improving peanut cultivars.The objective of this study was to assess cross-compatibility among cultivated and wild peanuts in crosses between...Wild peanut(Arachis)species are promising sources of disease resistance for improving peanut cultivars.The objective of this study was to assess cross-compatibility among cultivated and wild peanuts in crosses between eight peanut cultivars and 27 wild species carrying the A,B,E,Ex,F,K,P,and H genomes.Embryo culture and chromosome doubling led to polyploids representing hybrids between cultivated peanut and A.stenosperma,A.macedoi,A.duranensis,A.villosa,and A.diogoi.The first two showed greater resistance to bacterial wilt than their cultivated parents.DNA markers were developed for verifying the hybrids and for identifying translocation or introgression lines with alien chromosome fragments.展开更多
There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and grea...There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and great surface conformability.To meet these requirements,we designed and fabricated a flexible bioinspired meta-structure with ultra-broadband MA,thin thickness and excellent surface conformality.The carbonyl iron powder-carbon nanotubes-polydimethylsiloxane composite was synthesized by physical blending method for fabricating the MA meta-structure.Through geometry-electromagnetic optimal design by heuristic optimization algorithm,the meta-structure mimicking to the nipple photonic nanostructures on the eyes of moth can achieve ultra-broadband MA performance of 35.14 GHz MA bandwidth(reflection loss≤–10 dB),covering 4.86–40.00 GHz,with thickness of only 4.3 mm.Through simple fabrication processes,the meta-structure has been successfully fabricated and bonded on wings’leading edges,exhibiting excellent surface conformability.Furthermore,the designed flexible MA meta-structure possesses significant Radar Cross-Section(RCS)reduction capability,as demonstrated by the RCS analysis of an unmanned aerial vehicle.This flexible ultra-broadband MA meta-structure provides an outstanding candidate to meet the radar stealth requirement of variable curvature structures on aircraft.展开更多
Background:Over the past few decades,a threefold increase in obesity and type 2 diabetes(T2D)has placed a heavy burden on the health-care system and society.Previous studies have shown correlations between obesity,T2D...Background:Over the past few decades,a threefold increase in obesity and type 2 diabetes(T2D)has placed a heavy burden on the health-care system and society.Previous studies have shown correlations between obesity,T2D,and neurodegenera-tive diseases,including dementia.It is imperative to further understand the relation-ship between obesity,T2D,and cognitive deficits.Methods:This investigation tested and evaluated the cognitive impact of obesity and T2D induced by high-fat diet(HFD)and the effect of the host genetic background on the severity of cognitive decline caused by obesity and T2D in collaborative cross(CC)mice.The CC mice are a genetically diverse panel derived from eight inbred strains.Results:Our findings demonstrated significant variations in the recorded phenotypes across different CC lines compared to the reference mouse line,C57BL/6J.CC037 line exhibited a substantial increase in body weight on HFD,whereas line CC005 ex-hibited differing responses based on sex.Glucose tolerance tests revealed significant variations,with some lines like CC005 showing a marked increase in area under the curve(AUC)values on HFD.Organ weights,including brain,spleen,liver,and kidney,varied significantly among the lines and sexes in response to HFD.Behavioral tests using the Morris water maze indicated that cognitive performance was differentially affected by diet and genetic background.Conclusions:Our study establishes a foundation for future quantitative trait loci map-ping using CC lines and identifying genes underlying the comorbidity of Alzheimer's disease(AD),caused by obesity and T2D.The genetic components may offer new tools for early prediction and prevention.展开更多
High-entropy design is attracting growing interest as it offers unique structures and unprecedented application potential for ma-terials.In this article,a novel high-entropy ferrite(CoNi)_(x/2)(CuZnAl)_((1-x)/3)Fe_(2)...High-entropy design is attracting growing interest as it offers unique structures and unprecedented application potential for ma-terials.In this article,a novel high-entropy ferrite(CoNi)_(x/2)(CuZnAl)_((1-x)/3)Fe_(2)O_(4)(x=0.25,0.34,0.40,0.50)with a single spinel phase of space group Fd3m was successfully developed by the solid-state reaction method.By tuning the Co-Ni content,the magnetic properties of the material,especially the coercivity,changed regularly,and the microwave absorption properties were improved.In particular,the ef-fective absorption bandwidth of the material increased from 4.8 to 7.2 GHz,and the matched thickness decreased from 3.9 to 2.3 mm,while the minimum reflection loss remained below-20 dB.This study provides a practical method for modifying the properties of fer-rites used to absorb electromagnetic waves.展开更多
文摘Apomictic seed development is a complex process including formation of unreduced embryo sac,parthenogenetic embryo development from the egg cell,and endosperm formation either autonomously,or due to fertilization of polar nuclei by the sperm(under pseudogamous form of apomixis).In the latter case,an obstacle to the normal endosperm development is disturbance of maternal(m)-to-paternal(p)genomic ratio 2m:1p that occurs in the cases of pollination of unreduced embryo sac with haploid sperms.Usage of tetraploid pollinators can overcome this problem because in such crosses maternal-to-paternal genomic ratio is 4m:2p that provides formation of kernels with plump endosperm.Using tetraploid lines as pollen parents we observed formation of plump kernels on the ears and panicles of diploid maize and sorghum accessions.These kernels had hybrid endosperm and diploid maternal-type embryo or hybrid embryo with different ploidy level(2n,3n,4n).The frequencies of plump kernels on the ear ranged from 0.2-0.3%to 5.7-6.2%counting from the number of ovaries.Maternal-type plants were found in two maize lines,their frequency varying from 10.7 to 37.5%of the progeny plants.In CMS-lines of sorghum pollinated with tetraploid sorghum accessions,the frequency of plump kernels ranged from 0.6 to 14.0%counting from the number of ovaries;the frequency of maternal-type plants varied from 33.0 up to 96.1%.The hybrid nature of endosperm of the kernels that gave rise to maternal-type plants has been proved by marker gene expression and by SDS-electrophoresis of endosperm proteins.These data testify to variable modes of seed formation under diploid×tetraploid crosses in maize and sorghum both by amphi-and by apomixis.Therefore,usage of tetraploid pollinators might be a promising approach for isolation of apomixis in maize and sorghum accessions.
基金supported by a grant from the Department of Science and Technique and Education in Hubei Province(2000B05006 and 2001 AA204A01)the 9th Key Pro-jects of Chinese Academy of Sciences(KY951A13029).
文摘Comparison of seed setting rate,plant height and Cheng's morphological traits were made between the F_(2)progeny of indica-japonica hybrids,02428/Pei'ai 64 and Taichung 65/Teqing.There existed resemblance normal distribution in plant height,and the distribution had no relationship with the seed setting rate and plant height in F_(1)progeny,suggesting that there were no gametic selection for the plant height in the F_(2)progeny of indica-japoniea hybrids.An average seed setting rate of the F_(2)was equal to the F_(1)populations in the recombination of 02428/Pei'ai 64 in which there was an excellent cross compatibility,but the remarkable increase in the seed setting rate from the F_(1)to F_(2)in Taichung 65/Teqing,indicating that gametic selection only took place in the indica-japonica crosses with low cross compatibility while null or little in the hybrids with high compatibility.There were many intermediate types among the leaf pubescence,color of hull at heading,and length of the first and second panicle internode,and these Cheng's morphological traits was distributed normally;there were also a little intermediate types in hull hairness and phenol reaction with bi-peak distribution;while length to width ratio of grain was inclined to the japonica types obviously showing a skewed distribution in the F_(2)population.Although Cheng's morphological traits in F_(2)populations had inconsistent distribution types,Cheng's morphological traits index showed normal distribution,which suggested that intermediate types,i.e.indicalinous or japonicalinous,were primary in F_(2)population.
文摘Indica and japonica rices are two subspecies ofAsia cultivated rice.Their grain qualities exista significant difference.The objective of thispaper is to study the genetic control of qualitytraits in intersubspecies crosses of rice.In 1991,4 japonica varieties with widecompatibility,PC311,Zhenxiqiuguang,Lun-hui 422,and Ce 03 were crossed with 5 indicavarieties,3037,Zaoxiandang 18,IR36,Minghui 63,and Yangdao 4 according to NC(?)design.The 20 hybrids using japonica as ma-
基金supported by the National Key Research and Development Program of China (2016YFD0101804)the National Natural Science Foundation of China (31671280)HarvestPlus (part of the CGIAR Research Program on Agriculture for Nutrition and Health, http://www.harvestplus.org/)
文摘Pure lines derived from multiple parents provide abundant variation for genetic study.However,efficient genetic analysis methods and user-friendly software are still lacking.In this study, we developed linkage analysis methods and integrated analysis software for pure-line populations derived from four-way and eight-way crosses.First, polymorphic markers are classified into different categories according to the number of identifiable alleles in the inbred parents.Expected genotypic probability is then derived for each pair of complete markers, and based on them a maximum likelihood estimate(MLE) of recombination frequency is calculated.An EM algorithm is proposed for calculating recombination frequencies in scenarios that at least one marker is incomplete.A linkage map can thus be constructed using estimated recombination frequencies.We describe a software package called GAPL for recombination frequency estimation and linkage map construction in multi-parental pure-line populations.Both simulation studies and results from a reported four-way cross recombinant inbred line population demonstrate that the proposed method and software can build more accurate linkage maps in shorter times than other published software packages.The GAPL software is freely available from www.isbreeding.net and can also be used for QTL mapping in multi-parental populations.
文摘The F2, F3, families and F4 lines of six soybean crosses, were selected successively under high-and low - fertility sites with the relection objective of high yield and the method of pedigree was used. Two best F4 - derived lines were chosen from each of the six crosses under both high-and low-fertility for use in this study. In 1995, the total 24 lines were tested in high, medium and low fertility sites with the same experimental design (CRB) to study the selcctoin effects of high and low - fertility. The results suggested that high- and low-fertility had different selection effects. High fertility was more effective for selecting lines, which had higher yield under high-fertility and lower yield under low-fertility; low-fertility was better for selecting lines, which had higher yield under low-fertility and lower yield under low-fertility, and high fertility was somewhat better than low fertility for selecting lines, which had higher yield under both high and low-fertility. It revealed that the lines selected from high-fertility had superior yield potential. The lines selected from high-fertility had shorter plant height, more nodes on main stem, fewer branches, higher seed-stem ratio. The reverse was true for the lines selected from low-fertility . The lodging-resistance of the lines selected from highfertility was greater than that of the lines from low-fertility. The soil fertility level of breeding nursery should be chosen according to the breeding objective.
基金Project supported by the National Natural Science Foundation of China （Grant Nos. 10775055 and 11105002） and the Open-end Fund of State Key Laboratory of Structural Analysis for Industrial Equipment, China （Grant No. GZ 1215）.
文摘The influence of the gap on the absorption performance of the conventional split ring resonator(SRR) absorber is investigated at microwave frequencies. Our simulated results reveal that the geometry of the square SRR can be equivalent to a Jerusalem cross(JC) resonator and its corresponding metamaterial absorber(MA) is changed to a JC absorber. The JC MA exhibits an experimental absorption peak of 99.1% at 8.72 GHz, which shows an excellent agreement with our simulated results. By simply assembling several JCs with slightly different geometric parameters next to each other into a unit cell, a perfect multi-band absorption can be effectively obtained. The experimental results show that the MA has four distinct and strong absorption peaks at 8.32 GHz, 9.8 GHz, 11.52 GHz and 13.24 GHz. Finally, the multi-reflection interference theory is introduced to interpret the absorption mechanism.
文摘The narrow genetic base in potato (Solanum tuberosum L.) limits the progress in cultivar development.The rich diploid germplasm in the origin center of potato provide a unique resource for improvement of tetraploid potatoes.Seven newly developed diploid hybrids with 2n pollen production,all of which have S. phureja background,were developed and evaluated for their value in potato breeding.They were crossed as male parnets to six tetraploid Solanum tuberosum cultivars,and seeds in large quantity from eleven crosses were obtained.Main agronomic traits,such as tuber yield,tuber number,mean tuber weight,tuber shape,eye depth,skin smoothness,flesh color,and specific gravity,were measured for 4x 2x tetraploid progenies in seedling generation,and their parents as well.All of the diploid hybrids had some merit for specific traits and the DH39 was more promising;high specific gravity trait in some diploid hybrids was successfully introgressed into tetroploid progenies via 4x 2x crosses.These diploid hybrids have potential value in potato breeding.
基金supported by the National Natural Science Foundation of China (Nos. 52175322, 52271031)the Natural Science Foundation of Jilin Province, China (No. SKL202302015)。
文摘The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones primarily precipitate in the sample aged at 200℃for 1 h(T6-200℃/1h),while the Al_(2)Ca phases mainly precipitate in the sample aged at 275℃for 8 h(T6-275℃/8h).The T6-200℃/1h sample exhibits excellent creep resistance,with a steady-state creep rate one order of magnitude lower than that of the T6-275℃/8h sample.The abnormally high stress exponent(~8.2)observed in the T6-200℃/1h sample is associated with the power-law breakdown mechanism.TEM analysis illuminates that the creep mechanism for the T6-200℃/1h sample is cross-slip between basal and prismatic dislocations,while the T6-275℃/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb.Compared with the Al_(2)Ca phase,the dense G.P.zones effectively impede dislocation climb and glide during the creep process,demonstrating superior creep resistance of the T6-200℃/1h sample.
文摘Mai Weitong,an illustrator and motion-graphic artist,based in London,the United Kingdom,has been drawing since she was a child,immersed in both Eastern and Western artistic environments.In 2017,after she graduated from Camberwell College of Arts,in the UK,with a bachelor’s degree in illustration,Mai became a freelance illustrator,and she began collaborating with various publishers and advertising agencies to create book illustrations and promotional artwork.In her work,she has revitalized Eastern elements with contemporary illustrations.Through her illustrations,Mai creates bridges of cross-cultural communication,which she uses to help introduce talented Asian illustrators to international audiences.
基金supported by the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2024ZD0302502 for WZ)the National Natural Science Foundation of China(Grant No.92365210 for WZ)+1 种基金Tsinghua Initiative Scientific Research Program (for WZ)the project of Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies (JIAOT,for YH)。
文摘To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.
基金supported by“National Key R&D Program of China(2021YFD2200203)”“the Fundamental Research Funds for the Central Universities(No.2572022AW02 and No.2572023CT19)”。
文摘Hybridization remains an important method for breeding new poplar varieties.It results in significant variation in leaf phenotype among parents and offspring,and among offspring themselves.This study aimed to investigate whether leaf shape variations were similar in offspring produced from reciprocal crosses.Specifically,two hybrid combinations were produced:the direct cross with Populus ussuriensis as the maternal parent and P.simonii×P.nigra as the paternal parent(HY53),and the reciprocal cross with P.simonii×P.nigra as the maternal parent and P.ussuriensis as the paternal parent(HY268).Using 3-month-old rooted cuttings from 40 clones(36 F1 hybrids and their parents)growing in a greenhouse,we measured and analyzed 14 leaf morphological traits to assess genetic variation and heterosis.The results showed HY53 clones generally exhibited greater average height than HY268 clones.Leaf phenotypes differed between the two hybrid combinations,with significant differences observed among parents and offspring for almost all traits,as revealed by analysis of variance(ANOVA).The phenotypic coefficient of variation was higher in HY268 clones.Additionally,leaf traits demonstrated high repeatability.Notably,some hybrid offspring exhibited positive or negative mid-parent heterosis,as well as over-parent heterosis for certain leaf phenotypes.The systematic cluster analysis further indicated distinct separation among HY268 clones.This research provides valuable materials for poplar breeding and offers insights into hybrid vigor in wood plants.The findings highlight the importance of reciprocal crossing in influencing leaf phenotype variation and heterosis,offering practical insights for future breeding strategies.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1403800 and 2023YFA1407300)the National Natural Science Foundation of China(Grant Nos.12374153,12447101,and 11974362)supported by the U.S.Department of Energy,Basic Energy Sciences(Grant No.DE-FG02-99ER45747)。
文摘Motivated by the recent discovery of charge density wave(CDW)order in the magnetic kagomémetal Fe Ge,we study the single-orbital t-N-V_(1)-V_(2)model on the kagomélattice,where N,V_(1),and V_(2)are the onsite,nearest neighbor,and next-nearest-neighbor Coulomb interactions,respectively.When the Fermi level lies in the flat band,the instability toward ferromagnetic(FM)order gives rise to a FM half-metal at sufficiently large onsite N.Intriguingly,at band filling n=17/24,the Fermi level crosses the van Hove singularity of the spin-minority bands of the half-metal.We show that,due to the unique geometry and sublattice interference on the kagomélattice at van Hove singularity,the inter-site Coulomb interactions V_(1) and V_(2)drive a real and an imaginary bond-ordered 2a_(0)×2a_(0) CDW instability,respectively.The FM loop current CDW with complex bond orders is a spin-polarized Chern insulator exhibiting the quantum anomalous Hall effect.The bond fluctuations are found to be substantially enhanced compared to the corresponding nonmagnetic kagomémetals at van Hove filling,providing a concrete model realization of the bond-ordered CDWs,including the FM loop current CDW,over the onsite charge density ordered states.When the spins are partially polarized at an intermediate N,we find that the interplay of CDW and magnetism enables the formation of real and complex bond-ordered CDWs,and the CDW transition is accompanied by a substantial enhancement in the ordered magnetic moments.These findings provide physical insights for the emergence of 2a_(0)×2a_(0) CDWs and their interplay with magnetism on the kagomélattice,and capture the essential physics observed experimentally in Fe Ge.
基金supported by National Natural Science Foundation of China(32272153)Henan Province Science and Technology R&D Joint Fund(232301420025)+4 种基金National Key Research and Development Program of China(2023YFD1200200)the Key Research Project of the Shennong Laboratory(SN01-2022-03)Independent Innovation Foundation of Henan Academy of Agricultural Sciences(2024ZC024)China Agriculture Research System(CARS-13)Henan Provincial Agriculture Research System(S2012-5).
文摘Wild peanut(Arachis)species are promising sources of disease resistance for improving peanut cultivars.The objective of this study was to assess cross-compatibility among cultivated and wild peanuts in crosses between eight peanut cultivars and 27 wild species carrying the A,B,E,Ex,F,K,P,and H genomes.Embryo culture and chromosome doubling led to polyploids representing hybrids between cultivated peanut and A.stenosperma,A.macedoi,A.duranensis,A.villosa,and A.diogoi.The first two showed greater resistance to bacterial wilt than their cultivated parents.DNA markers were developed for verifying the hybrids and for identifying translocation or introgression lines with alien chromosome fragments.
基金supported by the Basic Research Development Program of China(No.JCKY2021607B036)the National Natural Science Foundation of China(No.52275512).
文摘There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and great surface conformability.To meet these requirements,we designed and fabricated a flexible bioinspired meta-structure with ultra-broadband MA,thin thickness and excellent surface conformality.The carbonyl iron powder-carbon nanotubes-polydimethylsiloxane composite was synthesized by physical blending method for fabricating the MA meta-structure.Through geometry-electromagnetic optimal design by heuristic optimization algorithm,the meta-structure mimicking to the nipple photonic nanostructures on the eyes of moth can achieve ultra-broadband MA performance of 35.14 GHz MA bandwidth(reflection loss≤–10 dB),covering 4.86–40.00 GHz,with thickness of only 4.3 mm.Through simple fabrication processes,the meta-structure has been successfully fabricated and bonded on wings’leading edges,exhibiting excellent surface conformability.Furthermore,the designed flexible MA meta-structure possesses significant Radar Cross-Section(RCS)reduction capability,as demonstrated by the RCS analysis of an unmanned aerial vehicle.This flexible ultra-broadband MA meta-structure provides an outstanding candidate to meet the radar stealth requirement of variable curvature structures on aircraft.
文摘Background:Over the past few decades,a threefold increase in obesity and type 2 diabetes(T2D)has placed a heavy burden on the health-care system and society.Previous studies have shown correlations between obesity,T2D,and neurodegenera-tive diseases,including dementia.It is imperative to further understand the relation-ship between obesity,T2D,and cognitive deficits.Methods:This investigation tested and evaluated the cognitive impact of obesity and T2D induced by high-fat diet(HFD)and the effect of the host genetic background on the severity of cognitive decline caused by obesity and T2D in collaborative cross(CC)mice.The CC mice are a genetically diverse panel derived from eight inbred strains.Results:Our findings demonstrated significant variations in the recorded phenotypes across different CC lines compared to the reference mouse line,C57BL/6J.CC037 line exhibited a substantial increase in body weight on HFD,whereas line CC005 ex-hibited differing responses based on sex.Glucose tolerance tests revealed significant variations,with some lines like CC005 showing a marked increase in area under the curve(AUC)values on HFD.Organ weights,including brain,spleen,liver,and kidney,varied significantly among the lines and sexes in response to HFD.Behavioral tests using the Morris water maze indicated that cognitive performance was differentially affected by diet and genetic background.Conclusions:Our study establishes a foundation for future quantitative trait loci map-ping using CC lines and identifying genes underlying the comorbidity of Alzheimer's disease(AD),caused by obesity and T2D.The genetic components may offer new tools for early prediction and prevention.
基金supported by the National Natural Science Foundation of China(No.52371231)the Key Research and Development Program of Shanxi Province,China(No.202102030201006)+1 种基金the Central Government Guides Local Science and Technology Development Special Fund Project(No.YDZJSX2022B003),the Natural Science Foundation of Shanxi Province,China(No.202203021212205)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China(No.2022L074).
文摘High-entropy design is attracting growing interest as it offers unique structures and unprecedented application potential for ma-terials.In this article,a novel high-entropy ferrite(CoNi)_(x/2)(CuZnAl)_((1-x)/3)Fe_(2)O_(4)(x=0.25,0.34,0.40,0.50)with a single spinel phase of space group Fd3m was successfully developed by the solid-state reaction method.By tuning the Co-Ni content,the magnetic properties of the material,especially the coercivity,changed regularly,and the microwave absorption properties were improved.In particular,the ef-fective absorption bandwidth of the material increased from 4.8 to 7.2 GHz,and the matched thickness decreased from 3.9 to 2.3 mm,while the minimum reflection loss remained below-20 dB.This study provides a practical method for modifying the properties of fer-rites used to absorb electromagnetic waves.
