p-d Orbital Hybridization Engineered Single-Atom Catalyst for Electrocatalytic Ammonia Synthesis

The rational design of metal single-atom catalysts(SACs)for electrochemical nitrogen reduction reaction(NRR)is challenging.Two-dimensional metal-organic frameworks(2DMOFs)is a unique class of promising SACs.Up to now,the roles of individual metals,coordination atoms,and their synergy effect on the electroanalytic performance remain unclear.Therefore,in this work,a series of 2DMOFs with different metals and coordinating atoms are systematically investigated as electrocatalysts for ammonia synthesis using density functional theory calculations.For a specific metal,a proper metal-intermediate atoms p-d orbital hybridization interaction strength is found to be a key indicator for their NRR catalytic activities.The hybridization interaction strength can be quantitatively described with the p-/d-band center energy difference(Δd-p),which is found to be a sufficient descriptor for both the p-d hybridization strength and the NRR performance.The maximum free energy change(ΔG_(max))andΔd-p have a volcanic relationship with OsC_(4)(Se)_(4)located at the apex of the volcanic curve,showing the best NRR performance.The asymmetrical coordination environment could regulate the band structure subtly in terms of band overlap and positions.This work may shed new light on the application of orbital engineering in electrocatalytic NRR activity and especially promotes the rational design for SACs.

Morphological and molecular evidence for natural hybridization between Sorbus pohuashanensis and S. discolor (Rosaceae)

In overlapping distribution areas of Sorbus pohuashanensis and S.discolor in North China(Mount Tuoliang,Mount Xiling and Mount Baihua),Sorbus indi-viduals were found with pink fruit,which have never been recorded for the flora of China.Fourteen morphological characters combined with four chloroplast DNA markers and internal transcribed spacer(ITS)were used to analyze the origin of the Sorbus individuals with pink fruits and their relationship to S.pohuashanensis and S.discolor.PCA,SDA and one-way(taxon)ANOVA of morphological characters provided convincing evidence of the hybrid ori-gin of Sorbus individuals with pink fruits based on a novel morphological character and many intermediate characters.Haplotype analysis based on four cpDNA markers showed that either S.pohuashanensis or S.discolor were maternal parents of Sorbus individuals with pink fruits.Incongru-ence of the position of Sorbus individuals with pink fruits between cpDNA and ITS in cluster trees supported by DNA sequence comparative analysis,implying former hybridiza-tion events between S.pohuashanensis and S.discolor.Mul-tiple hybridization events between S.pohuashanensis and S.discolor might have contributed to the generation of Sorbus individuals with pink fruits.This study has provided insights into hybridization between species of the same genus in sympatric areas,which is of great significance for the study of interspecific hybridization.

Cryptic diversity and rampant hybridization in annual gentians on the Qinghai-Tibet Plateau revealed by population genomic analysis

Understanding the evolutionary and ecological processes involved in population differentiation and speciation provides critical insights into biodiversity formation. In this study, we employed 29,865 single nucleotide polymorphisms(SNPs) and complete plastomes to examine genomic divergence and hybridization in Gentiana aristata, which is endemic to the Qinghai-Tibet Plateau(QTP) region. Genetic clustering revealed that G. aristata is characterized by geographic genetic structures with five clusters(West, East, Central, South and North). The West cluster has a specific morphological character(i.e., blue corolla) and higher values of FSTcompared to the remaining clusters, likely the result of the geological barrier formed by the Yangtze River. The West cluster diverged from the other clusters in the Early Pliocene;these remaining clusters diverged from one another in the Early Quaternary. Phylogenetic reconstructions based on SNPs and plastid data revealed substantial cyto-nuclear conflicts. Genetic clustering and D-statistics demonstrated rampant hybridization between the Central and North clusters,along the Bayankala Mountains, which form the geological barrier between the Central and North clusters. Species distribution modeling demonstrated the range of G. aristata expanded since the Last Interglacial period. Our findings provide genetic and morphological evidence of cryptic diversity in G. aristata, and identified rampant hybridization between genetic clusters along a geological barrier.These findings suggest that geological barriers and climatic fluctuations have an important role in triggering diversification as well as hybridization, indicating that cryptic diversity and hybridization are essential factors in biodiversity formation within the QTP region.

Enhanced and asymmetric signatures of hybridization at climatic margins: Evidence from closely related dioecious fig species

Hybridization plays a significant role in biological evolution. However, it is not clear whether ecological contingency differentially influences likelihood of hybridization, particularly at ecological margins where parental species may exhibit reduced fitnesses. Moreover, it is unknown whether future ecosystem change will increase the prevalence of hybridization. Ficus heterostyla and F. squamosa are closely related species co-distributed from southern Thailand to southwest China where hybridization, yielding viable seeds, has been documented. As a robust test of ecological factors driving hybridization, we investigated spatial hybridization signatures based on nuclear microsatellites from extensive population sampling across a widespread contact range. Both species showed high population differentiation and strong patterns of isolation by distance. Admixture estimates exposed asymmetric interspecific gene flow.Signatures of hybridization increase significantly towards higher latitude zones, peaking at the northern climatic margins. Geographic variation in reproductive phenology combined with ecologically challenging marginal habitats may promote this phenomenon. Our work is a first systematic evaluation of such patterns in a comprehensive, latitudinally-based clinal context, and indicates that tendency to hybridize appears strongly influenced by environmental conditions. Moreover, that future climate change scenarios will likely alter and possibly augment cases of hybridization at ecosystem scales.

Cryptic divergences and repeated hybridizations within the endangered “living fossil” dove tree(Davidia involucrata) revealed by whole genome resequencing

The identification and understanding of cryptic intraspecific evolutionary units(lineages) are crucial for planning effective conservation strategies aimed at preserving genetic diversity in endangered species.However, the factors driving the evolution and maintenance of these intraspecific lineages in most endangered species remain poorly understood. In this study, we conducted resequencing of 77 individuals from 22 natural populations of Davidia involucrata, a “living fossil” dove tree endemic to central and southwest China. Our analysis revealed the presence of three distinct local lineages within this endangered species, which emerged approximately 3.09 and 0.32 million years ago. These divergence events align well with the geographic and climatic oscillations that occurred across the distributional range.Additionally, we observed frequent hybridization events between the three lineages, resulting in the formation of hybrid populations in their adjacent as well as disjunct regions. These hybridizations likely arose from climate-driven population expansion and/or long-distance gene flow. Furthermore, we identified numerous environment-correlated gene variants across the total and many other genes that exhibited signals of positive evolution during the maintenance of two major local lineages. Our findings shed light on the highly dynamic evolution underlying the remarkably similar phenotype of this endangered species. Importantly, these results not only provide guidance for the development of conservation plans but also enhance our understanding of evolutionary past for this and other endangered species with similar histories.

Scale-space effect and scale hybridization in image intelligent recognition of geological discontinuities on rock slopes

Geological discontinuity(GD)plays a pivotal role in determining the catastrophic mechanical failure of jointed rock masses.Accurate and efficient acquisition of GD networks is essential for characterizing and understanding the progressive damage mechanisms of slopes based on monitoring image data.Inspired by recent advances in computer vision,deep learning(DL)models have been widely utilized for image-based fracture identification.The multi-scale characteristics,image resolution and annotation quality of images will cause a scale-space effect(SSE)that makes features indistinguishable from noise,directly affecting the accuracy.However,this effect has not received adequate attention.Herein,we try to address this gap by collecting slope images at various proportional scales and constructing multi-scale datasets using image processing techniques.Next,we quantify the intensity of feature signals using metrics such as peak signal-to-noise ratio(PSNR)and structural similarity(SSIM).Combining these metrics with the scale-space theory,we investigate the influence of the SSE on the differentiation of multi-scale features and the accuracy of recognition.It is found that augmenting the image's detail capacity does not always yield benefits for vision-based recognition models.In light of these observations,we propose a scale hybridization approach based on the diffusion mechanism of scale-space representation.The results show that scale hybridization strengthens the tolerance of multi-scale feature recognition under complex environmental noise interference and significantly enhances the recognition accuracy of GD.It also facilitates the objective understanding,description and analysis of the rock behavior and stability of slopes from the perspective of image data.

Manipulating d-d orbital hybridization induced by Mo-doped Co_(9)S_(8) nanorod arrays for high-efficiency water electrolysis

Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water electrolysis.It has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities.Thanks to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,respectively.More impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) production.The innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.

Asymmetric orbital hybridization in Zn-doped antiperovskite Cu_(1-x)Zn_(x)NMn_(3)enables highly efficient electrocatalytic hydrogen production

Rational design of efficient and robust earth-abundant alkaline hydrogen evolution reaction(HER)catalysts is a key factor for developing energy conversion technologies.Currently,antiperovskite nitride CuNMn_(3)has garnered significant interest due to its remarkable properties such as negative/zero thermal expansion and magnetocaloric effects.However,when utilized as hydrogen evolution catalysts,it encounters large challenge resulting from excessively strong/weak interactions with adsorbed H on Mn/Cu active sites,which leads to low HER activity.In this study,we introduce an asymmetric orbital hybridization strategy in Zn-doped Cu_(1-x)Zn_(x)NMn_(3)by leveraging the localization of Zn electronic states to reconfigure the electronic structures of Cu and Mn,thereby reducing the energy barrier for water dissociation and optimizing Cu and Mn active sites for hydrogen adsorption and H_(2)production.Electrochemical evaluations reveal that Cu_(0.85)Zn_(0.15)NMn_(3)with x=0.15 demonstrates exceptional electrocatalytic activity in alkaline electrolytes.A low overpotential of 52 mV at 10 mA cm^(-2)and outstanding stability over a 150-h test period are achieved,surpassing commercial Pt/C.This research offers a novel strategy for enhancing HER performance by modulating asymmetric hybridization of electron orbitals between multiple metal atoms within a material structure.

Enhanced Redox Electrocatalysis in High‑Entropy Perovskite Fluorides by Tailoring d–p Hybridization

High-entropy catalysts featuring exceptional properties are,in no doubt,playing an increasingly significant role in aprotic lithium-oxygen batteries.Despite extensive effort devoted to tracing the origin of their unparalleled performance,the relationships between multiple active sites and reaction intermediates are still obscure.Here,enlightened by theoretical screening,we tailor a high-entropy perovskite fluoride(KCoMnNiMgZnF_(3)-HEC)with various active sites to overcome the limitations of conventional catalysts in redox process.The entropy effect modulates the d-band center and d orbital occupancy of active centers,which optimizes the d–p hybridization between catalytic sites and key intermediates,enabling a moderate adsorption of LiO_(2)and thus reinforcing the reaction kinetics.As a result,the Li–O2 battery with KCoMnNiMgZnF_(3)-HEC catalyst delivers a minimal discharge/charge polarization and long-term cycle stability,preceding majority of traditional catalysts reported.These encouraging results provide inspiring insights into the electron manipulation and d orbital structure optimization for advanced electrocatalyst.

aCGH应用于产前诊断意外发现DMD基因缺失或重复病例分析

目的 探讨微阵列比较基因组杂交(aCGH)技术应用在产前诊断中发现抗肌萎缩蛋白基因(又称DMD基因)缺失或重复的重要价值。方法 收集2019年9月至2020年7月在西北妇女儿童医院因高危因素(高龄、血清学筛查高风险、无创筛查高风险或超声软指标异常等)选择aCGH技术进行产前诊断的851例孕妇的羊水样本进行检测,并进一步采用多重连接探针扩增(MLPA)方法对DMD基因变异样本进行验证。结果 在851例孕妇的羊水样本中,经aCGH产前诊断时意外发现4例羊水样本存在DMD基因缺失或重复,同时MLPA检测验证了上述变异。胎儿1:男胎,arr[GRCh37]Xp21.1(31691172-31766673)×0,DMD基因E52-53缺失;胎儿2:男胎,arr[GRCh37]Xp21.2(31016983-31351900)×2,DMD基因E61-79重复;胎儿3:女胎,arr[GRCh37]Xp21.2(31182699-31474949)×3,DMD基因E58-74重复;胎儿4:男胎,arr[GRCh37]Xp21.1(31777925-32152126)×2,DMD基因E45-51重复。4例变异均遗传自母亲。结论 产前诊断是防止DMD患者出生的重要手段,aCGH技术用于产前诊断不仅可以检测染色体微缺失和微重复综合征,还有助于检测由基因缺失或重复引起的单基因疾病,从而为临床诊断及遗传咨询提供了理论依据。

An optimized protocol using Steedman’s wax for high-sensitivity RNA in situ hybridization in shoot apical meristems and flower buds of cucumber

In situ mRNA hybridization(ISH)is a powerful tool for examining the spatiotemporal expression of genes in shoot apical meristems and flower buds of cucumber.The most common ISH protocol uses paraffin wax;however,embedding tissue in paraffin wax can take a long time and might result in RNA degradation and decreased signals.Here,we developed an optimized protocol to simplify the process and improve RNA sensitivity.We combined embedding tissue in low melting-point Steedman’s wax with processing tissue sections in solution,as in the whole-mount ISH method in the optimized protocol.Using the optimized protocol,we examined the expression patterns of the CLAVATA3(CLV3)and WUSCHEL(WUS)genes in shoot apical meristems and floral meristems of Cucumis sativus(cucumber)and Arabidopsis thaliana(Arabidopsis).The optimized protocol saved 4–5 days of experimental period compared with the standard ISH protocol using paraffin wax.Moreover,the optimized protocol achieved high signal sensitivity.The optimized protocol was successful for both cucumber and Arabidopsis,which indicates it might have general applicability to most plants.

Plasmonic hybridization properties in polyenes octatetraene molecules based on theoretical computation

Relationship of plasmonic properties of multiple clusters to molecular interactions and properties of a single cluster or molecule have become increasingly important due to the continuous emergence of molecular and cluster devices or systems.A hybrid phenomenon similar to plasmonic nanoparticle hybridization exists between two molecules with plasmon excitation modes.We use linear-response time-dependent density functional theory,real-time propagation time-dependent density functional theory,the plasmonicity index,and transition contribution maps(TCMs)to identify the plasmon excitation modes for the linear polyenes octatetraene with–OH and–NH_(2)groups and analyze the hybridization characteristics using charge transitions.The results show that molecular plasmon hybridization exists when the two molecules are coupled.The TCM analysis shows that the plasmon modes and hybridization result from collective and single-particle excitation.The plasmon mode is stronger,and the individual properties of the molecules are maintained after coupling when there is extra charge depose in the molecules because the electrons are moving in the molecules.This study provides new insights into the molecular plasmon hybridization of coupled molecules.

土壤施硒量对杂交狼尾草生长和硒积累的影响

为探讨杂交狼尾草(P.americanum×P.purpureum)产能对富硒强化措施的响应,本研究采用盆栽试验,研究不同土壤施硒量(0,0.50,1.00,2.00,5.00,10.00,20.00,30.00,40.00和50.00 mg·kg^(-1))处理对杂交狼尾草幼苗成活率、产能和硒积累的影响。结果显示,土壤施硒量1.00 mg·kg^(-1)对杂交狼尾草的生长有促进作用;20.00 mg·kg^(-1)显著抑制幼苗的成活率和分蘖期的生长,对拔节期和成熟期植株影响不显著;40.00 mg·kg^(-1)抑制拔节期的生长。土壤施硒量≤5.00 mg·kg^(-1)时,杂交狼尾草地上部和根系对硒有较强的富集能力,富集能力强于紫云英、黑麦草和紫花苜蓿等;通过杂交狼尾草的生物转化,大量无机硒可转化为有机硒,而在≤5.00 mg·kg^(-1)施硒量下有机硒转化率最高,为56.19%~73.91%。研究表明,杂交狼尾草是一种富硒能力强的饲草,在土壤施硒量≤5.00 mg·kg^(-1)(土壤硒本底值为0.07 mg·kg^(-1))时对硒的富集效果最佳,有机硒转化率高,具备作为高硒、高值化饲料添加剂材料的开发潜力。

西葫芦新品种京葫42的选育

京葫42是以抗病自交系865为母本,以820为父本配制而成的温室专用抗病西葫芦一代杂种。中早熟,生长势强,茎秆粗壮,低温弱光下连续结瓜能力强,抗白粉病、小西葫芦花叶病毒(ZYMV)、西瓜花叶病毒(WMV)和番木瓜花叶病毒(PRSV);商品瓜翠绿色,中长柱形,瓜条顺直,商品性好;每667 m^(2)产量12000 kg左右,适宜华北、西北、黄淮海和东北地区越冬温室栽培。

辣椒新品种云干椒7号的选育

云干椒7号是以自交系258-1-2-3-1X-1为母本,以丘北辣椒优异单株390-1-1为父本配制而成的干制辣椒一代杂种。植株生长势及分枝性强,中熟,定植至采收约100 d(天),坐果率高;果实线形,老熟果深红色,平均果长11.5 cm,横径1.1 cm,干制后果面光滑油亮,平均单果干质量1.3 g,香辣味浓,辣椒素含量0.12%,VC含量1570.13 mg·kg^(-1);抗疫病,每667 m^(2)鲜椒产量920~1080 kg,干椒产量230~270 kg,制干率约25%,适宜云南省文山、曲靖、昭通、楚雄等干椒主产区及海拔2200 m以下的小果干椒类型地区春季栽培。

基于混合分解和PCG-BiLSTM的风速短期预测

为降低风速的随机性对风力发电的影响,提高风速短期预测的精准度,提出一种基于混合分解、双通道输入、多分支PCG-BiLSTM深度学习模型的短期风速预测方法。首先,将全年风速数据分为春、夏、秋、冬4个季度,选取春季作为主要实验对象;其次,利用奇异谱分解(SSD)和变分模态分解(VMD)以降低原始春季风速数据复杂度,生成具有不同模态且复杂度低的子分量,两种不同模式子分量组合为混合分量,实现不同模式分解算法的优势互补;最后,将混合分量以双通道的形式输入到多分支PCG-BiLSTM深度学习模型中,其模型的每个分支由卷积神经网络(CNN)与门控循环单元(GRU)并联组成时空特征提取模块,用于提取两种分解分量组合的混合分量的时空特征,各分支提取对应混合分量的时空特征经聚合后再由双向长短期记忆网络(BiLSTM)进一步提取风速信号的正向和反向双向波动规律,进而得到最终的风速预测结果。多组实验结果表明:提出的组合预测方法在短期风速预测中具有较高的精度和泛化能力,优于其他传统预测方法。

中国混合动力汽车动力总成技术进展

在国家政策与市场需求的双重驱动下,2021年以来,中国品牌混合动力汽车动力总成技术实现突破,围绕中国市场特点与消费者用车习惯推出一批具有中国特色、世界范围内领先的混合动力汽车产品。近期混合动力汽车市场销量呈爆发式增长,2023年中国市场混合动力乘用车销售超300万辆,同比增长83%。然而,受近年来汽车领域电动化浪潮影响,行业内尚存关于混合动力汽车仅为过渡性技术的观点,部分消费者对国产混动汽车技术产品力仍存质疑。为纠正对混合动力汽车的片面性、偏见性认识,该文围绕中国混合动力汽车动力总成技术路线展开,聚焦多样化的混动架构与专用化的核心部件,提出新的混合度定义作为动力总成电气化程度的统一评价标准,探讨国内外主流混动技术异同,剖析当下中国最前沿的混动技术特点与发展趋势,厘清中国混动汽车动力总成的发展脉络。研究表明:中国式混动汽车以大容量动力电池与插电式混合动力为技术特色,实现发动机、电机两大驱动动力源以及动力电池、增程系统两大动力能量源的灵活混合与优势互补。与纯内燃机车相比,得益于电驱动技术辅助,混合动力汽车聚焦提高发动机热效率、发动机高效区利用率以及整车燃油经济性。与纯电动车相比,混合动力汽车则基于发动机的增程发电,以高性价比和高便利度解决纯电动车的补能焦虑;并通过结合发动机直驱、变速器动力放大等机械驱动技术,以更低的硬件成本实现更稳定的强劲动力输出。混合动力汽车的独特优势使其作为长期性技术路线,将成为带动汽车产业向碳中和方向转型升级的关键,该文对当下市场的深度分析和未来趋势的理性推测将为中国混动技术的进一步发展提供有益参考。

梨杂交F_(1)果实性状遗传倾向分析

以延边大香水为母本,红香酥、早酥、红茄、晋酥、晋密、鄂梨1号和云红1号为父本的7个梨杂交组合F_(1)为试材,对果实性状进行连续3年调查,总结分析果实性状遗传倾向,以期为梨遗传育种提供参考依据。结果表明:杂种F_(1)单果重、果实横径、果实纵径、果柄长度、果柄粗度、果形指数及可溶性固形物等7个性状都有趋中遗传倾向。其中,单果重产生退化,向小果遗传趋势强;可溶性固形物和果形指数变异系数较小,遗传传递力较高;果柄粗度呈趋中偏低遗传,果柄长度、果实横径、果实纵径呈趋中偏高遗传。对不同组合果实性状遗传倾向研究认为果实底色、萼片类型、萼洼深度、质地、汁液、风味等性状受母本影响较大,为母性遗传;萼洼广度有趋中遗传倾向;果实香气受父本影响较大;果实面色可隔代遗传。以上研究结果为梨果实性状遗传规律研究及杂交育种亲本的选择选配提供参考价值。

计算全息检测技术的精度溯源研究现状分析(内封面文章)

随着光学系统性能的要求越来越高,非球面、自由曲面等复杂光学曲面能够提升系统的成像性能,因此提升复杂光学曲面的检测精度极为重要。干涉检测是测量复杂光学曲面的重要手段,其中计算全息检测法(Computer Generated Hologram,CGH)作为干涉检测中的一种,因其精度高和设计自由度大等优点得到了广泛的应用。但是在CGH检测复杂曲面的过程中存在的各类误差会影响波前检测的精度。文中首先介绍了计算全息法的检测精度现状,其次归纳总结了造成计算全息法误差的主要因素。分别介绍了不同误差的产生原理、影响效果、相对应标定补偿方法及适用情景和优缺点;并介绍了基于CGH占空比与线条位置误差的调研现状分析以及现有的研究方法;最后对计算全息法检测的精度溯源和精度提升研究趋势进行了展望。

香型优质高产杂交稻新品种野香优669的选育与应用

【目的】选育产量、米质和抗性相协调的香型优质水稻新品种。【方法】利用亲本间的遗传多样性和农艺性状的互补性,以高产、高配合力的父本福恢669与香型、优质、抗病的不育系野香A杂交,结合多生态点抗性鉴定、高温逼熟后品质分析、多年多点品比试验等相结合。【结果】选育出优质、高产、抗病,株叶态协调的杂交稻品种野香优669。2019–2020年参加福建省中稻区域试验,全生育期两年平均139.8 d,比对照II优3301早熟1.1d,产量平均9363 kg·hm^(-2),比对照增产2.24%,未达显著水平。两年稻瘟病抗性鉴定综合评价为抗稻瘟病,稻米品质达部颁一等优质食用稻品种品质标准,2021年通过福建省农作物审定委员会审定(闽审稻20210014)。野香优669聚合了来自双亲的22个有利基因,其中6个为单方携带,16个为双亲均携带。【结论】野香优669产量高、抗性强、品质好、口感佳,在生产上大面积推广应用,是福建省农业主推品种之一。