调控铝在ITH沸石骨架中的位置以用于催化甲醇制烯烃

随着低碳烯烃需求量的增加,甲醇制烯烃(MTO)成为由非石油资源制取低碳烯烃的关键技术,其中沸石由于具有可调节的酸度、有序的微孔结构和较好的择型性能而被广泛用作MTO反应催化剂.ITQ-13沸石(ITH拓扑结构)由于其独特的九元环结构在MTO反应中表现出较好的丙烯选择性和反应寿命,引起了广泛关注.研究表明,分子筛的酸中心分布与MTO反应性能密切相关,因此,研究ITQ-13沸石中铝分布与MTO反应性能的关系,对进一步提升其MTO催化性能具有重要意义.本文分别以与ITH具有共同基本结构单元(双四元环,D4Rs)的LTA沸石(LTA-ITH)和薄水铝石(C-ITH)为铝源,合成了两类铝硅酸盐ITH沸石.X射线衍射、扫描电子显微镜以及氮气吸脱附表征结果表明,这两类分子筛具有相似的片状形貌和微孔性质.氨气程序升温脱附结果表明,具有相近硅铝比的两类ITH沸石具有相近的酸量.进一步采用27Al魔角旋转核磁共振(MAS NMR)、密度泛函理论计算和1-己烯裂解反应对两类ITH分子筛的铝分布进行研究.结果表明,两类分子筛具有不同的铝分布,LTA-ITH中有更多的铝进入ITH的正弦孔道与直孔道,而C-ITH中有更多的铝分布在交叉孔道.当前,研究者普遍认为MTO反应过程遵循双循环烃池机理,ITH交叉孔道由于具有较大的空间,相比于正弦孔道和直孔道,更有利于芳烃循环中间体的产生,从而有利于形成芳烃循环产物(乙烯),而正弦孔道和直孔道却更有利于烯烃循环过程,导致产生更多的丙烯.对两类ITH进行了MTO催化性能测试,结果表明,LTA-ITH比C-ITH表现出更高的丙烯选择性,并且表现出更高的丙烯与乙烯的比率,表明其烯烃循环过程得到加强,这与^(27)Al MAS NMR以及1-己烯裂解反应得到的结论一致,进一步证明ITH分子筛的铝分布得到有效调控.综上,本文阐明了ITH沸石中铝分布与其反应性能的关系,为调整沸石骨架中的Al位点提供一种新策略,为未来制备高效的MTO沸石基催化剂提供参考.

Microstructure and water-swelling mechanism of red-bed mudstone in the Xining region,Northeastern Tibetan Plateau

This paper examines the effect of the microstructure and electrical conductivity(EC)on the swelling ratio and pressure in red-bed mudstone sampled from arid areas in the Xining region in the northeastern Tibetan Plateau.A series of laboratory tests,including swelling experiments,X-ray diffraction(XRD),and scanning electron microscope(SEM),was carried out for mechanical and microstructural analysis.The coupled influence of the EC and microstructural parameters on the expansion ratio and pressure was investigated,and the weight coefficients were discussed by the entropy weight method.The results revealed an increasing exponential trend in EC,and the maximum swelling speed occurred at an EC of approximately 10 μS/cm.In addition,a method for predicting the expansion potential is proposed based on the microstructure,and its reliability is verified by comparing with swelling experimental results.In addition,according to the image analysis results,the ranges of the change in the clay minerals content(CMC),the fractal dimension(FD),the average diameter(AD)of pores,and the plane porosity(PP)are 23.75%-53%,1.08-1.17,7.53-22.45 mm,and 0.62%-1.25%,respectively.Moreover,mudstone swelling is negatively correlated with the plane porosity,fractal dimension and average diameter and is linearly correlated with the clay mineral content.Furthermore,the weight values prove that the microstructural characteristics,including FD,AD,and PP,are the main factors influencing the expansion properties of red-bed mudstones in the Xining region.Based on the combination of macro and micro-analyses,a quantitative analysis of the swelling process of mudstones can provide a better reference for understanding the mechanism of expansion behavior.

Oxygen tension modulates cell function in an in vitro three-dimensional glioblastoma tumor model

Hypoxia is a typical feature of the tumor microenvironment,one of the most critical factors affecting cell behavior and tumor progression.However,the lack of tumor models able to precisely emulate natural brain tumor tissue has impeded the study of the effects of hypoxia on the progression and growth of tumor cells.This study reports a three-dimensional(3D)brain tumor model obtained by encapsulating U87MG(U87)cells in a hydrogel containing type I collagen.It also documents the effect of various oxygen concentrations(1%,7%,and 21%)in the culture environment on U87 cell morphology,proliferation,viability,cell cycle,apoptosis rate,and migration.Finally,it compares two-dimensional(2D)and 3D cultures.For comparison purposes,cells cultured in flat culture dishes were used as the control(2D model).Cells cultured in the 3D model proliferated more slowly but had a higher apoptosis rate and proportion of cells in the resting phase(G0 phase)/gap I phase(G1 phase)than those cultured in the 2D model.Besides,the two models yielded significantly different cell morphologies.Finally,hypoxia(e.g.,1%O2)affected cell morphology,slowed cell growth,reduced cell viability,and increased the apoptosis rate in the 3D model.These results indicate that the constructed 3D model is effective for investigating the effects of biological and chemical factors on cell morphology and function,and can be more representative of the tumor microenvironment than 2D culture systems.The developed 3D glioblastoma tumor model is equally applicable to other studies in pharmacology and pathology.

Design Framework of Unsourced Multiple Access for 6G Massive IoT

In this paper,ambient IoT is used as a typical use case of massive connections for the sixth generation(6G)mobile communications where we derive the performance requirements to facilitate the evaluation of technical solutions.A rather complete design of unsourced multiple access is proposed in which two key parts:a compressed sensing module for active user detection,and a sparse interleaver-division multiple access(SIDMA)module are simulated side by side on a same platform at balanced signal to noise ratio(SNR)operating points.With a proper combination of compressed sensing matrix,a convolutional encoder,receiver algorithms,the simulated performance results appear superior to the state-of-the-art benchmark,yet with relatively less complicated processing.

Three‐dimensional(3D)‐printed MXene high‐voltage aqueous micro‐supercapacitors with ultrahigh areal energy density and low‐temperature tolerance

The rapid advancement in the miniaturization,integration,and intelligence of electronic devices has escalated the demand for customizable microsupercapacitors(MSCs)with high energy density.However,efficient microfabrication of safe and high‐energy MXene MSCs for integrating microelectronics remains a significant challenge due to the low voltage window in aqueous electrolytes(typically≤0.6 V)and limited areal mass loading of MXene microelectrodes.Here,we tackle these challenges by developing a highconcentration(18mol kg^(−1))“water‐in‐LiBr”(WiB)gel electrolyte for MXene symmetric MSCs(M‐SMSCs),demonstrating a record high voltage window of 1.8 V.Subsequently,additive‐free aqueous MXene ink with excellent rheological behavior is developed for three‐dimensional(3D)printing customizable all‐MXene microelectrodes on various substrates.Leveraging the synergy of a highvoltage WiB gel electrolyte and 3D‐printed microelectrodes,quasi‐solid‐state MSMSCs operating stably at 1.8 V are constructed,and achieve an ultrahigh areal energy density of 1772μWhcm^(−2) and excellent low‐temperature tolerance,with a long‐term operation at−40℃.Finally,by extending the 3D printing protocol,M‐SMSCs are integrated with humidity sensors on a single planar substrate,demonstrating their reliability in miniaturized integrated microsystems.

The role of intestinal flora on tumorigenesis,progression,and the efficacy of PD-1/PD-L1 antibodies in colorectal cancer

Intestinal flora affects the maturation of the host immune system,serves as a biomarker and efficacy predictor in the immunotherapy of several cancers,and has an important role in the development of colorectal cancer(CRC).Anti-PD-1/PD-L1 antibodies have shown satisfactory results in MSI-H/d MMR CRC but performed poorly in patients with MSS/p MMR CRC.In recent years an increasing number of studies have shown that intestinal flora has an important impact on anti-PD-1/PD-L1 antibody efficacy in CRC patients.Preclinical and clinical evidence have suggested that anti-PD-1/PD-L1 antibody efficacy can be improved by altering the composition of the intestinal flora in CRC.Herein,we summarize the studies related to the influence of intestinal flora on anti-PD-1/PD-L1 antibody efficacy in CRC and discuss the potential underlying mechanism(s).We have focused on the impact of the intestinal flora on the efficacy and safety of anti-PD-1/PD-L1 antibodies in CRC and how to better utilize the intestinal flora as an adjuvant to improve the efficacy of anti-PD-1/PD-L1 antibodies.In addition,we have provided a basis for the potential of the intestinal flora as a new treatment modality and indicator for determining patient prognosis.

Sustainable nitrogen fixation by bubble discharge plasma:Performance optimization and mechanism

Sustainable nitrogen fixation driven by renewable energy sources under mild conditions has been widely sought to replace the industrial Haber-Bosch process.The fixation of nitrogen in the form of NO_(x)^(-)and NH_4^(+)into aqueous solutions using electricity-driven gas-liquid discharge plasma is considered a promising prescription.In this paper,a scalable bubble discharge excited by nanosecond pulse power is employed for nitrogen fixation in the liquid phase.The nitrogen fixation performance and the mechanisms are analyzed by varying the power supply parameters,working gas flow rate and composition.The results show that an increase in voltage and frequency can result in an enhanced NO_(3)^(-)yield.Increases in the gas flow rate can result in inadequate activation of the working gas,which together with more inefficient mass transfer efficiencies can reduce the yield.The addition of O_(2) effectively elevates NO_(3)^(-)production while simultaneously inhibiting NH_4^(+) production.The addition of H_(2)O vapor increases the production of OH and H,thereby promoting the generation of reactive nitrogen and enhancing the yield of nitrogen fixation.However,the excessive addition of O_(2) and H_(2)O vapor results in negative effect on the yield of nitrogen fixation,due to the significant weakening of the discharge intensity.The optimal nitrogen fixation yield was up to 16.5 μmol/min,while the optimal energy consumption was approximately 21.3 MJ/mol in this study.Finally,the mechanism related to nitrogen fixation is discussed through the optical emission spectral(OES) information in conjunction with the simulation of energy loss paths in the plasma by BOLSIG+.The work advances knowledge of the effect of parameter variations on nitrogen fixation by gas-liquid discharge for higher yield and energy production.

Enhanced degradation of tetracycline by gas-liquid discharge plasma coupled with g-C_(3)N_(4)/TiO_(2)

Plasma-catalysis is considered as one of the most promising technologies for antibiotic degradation in water.In the plasma-catalytic system,one of the factors affecting the degradation effect is the performance of the photocatalyst,which is usually restricted by the rapid recombination of electrons and holes as well as narrow light absorption range.In this research,a photocatalyst g-C_(3)N_(4)/TiO_(2) was prepared and coupled with gas-liquid discharge(GLD)to degrade tetracycline(TC).The performance was examined,and the degradation pathways and mechanisms were studied.Results show that a 90%degradation rate is achieved in the GLD with g-C_(3)N_(4)/TiO_(2) over a 10 min treatment.Increasing the pulse voltage is conducive to increasing the degradation rate,whereas the addition of excessive g-C_(3)N_(4)/TiO_(2) tends to precipitate agglomerates,resulting in a poor degradation efficiency.The redox properties of the g-C_(3)N_(4)/TiO_(2) surface promote the generation of oxidizing active species(H2O2,O3)in solution.Radical quenching experiments showed that·OH,hole(h^(+)),play important roles in the TC degradation by the discharge with g-C_(3)N_(4)/TiO_(2).Two potential degradation pathways were proposed based on the intermediates.The toxicity of tetracycline was reduced by treatment in the system.Furthermore,the g-C_(3)N_(4)/TiO_(2) composites exhibited excellent recoverability and stability.

{1012}twin–twin intersection-induced lattice rotation and dynamic recrystallization in Mg–6Al–3Sn–2Zn alloy

This study investigated the formation mechanism of new grains due to twin–twin intersections in a coarse-grained Mg–6Al–3Sn–2Zn alloy during different strain rates of an isothermal compression.The results of electron backscattered diffraction investigations showed that the activated twins were primarily{1012}tension twins,and 60°<1010>boundaries formed due to twin–twin intersections under different strain rates.Isolated twin variants with 60°<1010>boundaries transformed into new grains through lattice rotations at a low strain rate(0.01 s^(−1)).At a high strain rate(10 s^(−1)),the regions surrounded by subgrain boundaries through high-density dislocation arrangement and the 60°<1010>boundaries transformed into new grains via dynamic recrystallization.

Customized modulation on plasma uniformity by non-uniform magnetic field in capacitively coupled plasma

A two-dimensional fluid model based on COMSOL Multiphysics is developed to investigate the modulation of static magnetic field on plasma homogeneity in a capacitively coupled plasma(CCP)chamber. To generate a static magnetic field, direct current is applied to a circular coil located at the top of the chamber. By adjusting the magnetic field's configuration, which is done by altering the coil current and position, both the plasma uniformity and density can be significantly modulated. In the absence of the magnetic field, the plasma density exhibits an inhomogeneous distribution characterized by higher values at the plasma edge and lower values at the center. The introduction of a magnetic field generated by coils results in a significant increase in electron density near the coils. Furthermore, an increase in the sets of coils improves the uniformity of the plasma. By flexibly adjusting the positions of the coils and the applied current,a substantial enhancement in overall uniformity can be achieved. These findings demonstrate the feasibility of using this method for achieving uniform plasma densities in industrial applications.

Type Synthesis of Fully Decoupled Three Translational Parallel Mechanism with Closed-Loop Units and High Stifness

In order to solve the problem of weak stifness of the existing fully decoupled parallel mechanism, a new synthesis method of fully decoupled three translational (3T) parallel mechanisms (PMs) with closed-loop units and high stifness is proposed based on screw theory. Firstly, a new criterion for the full decoupled of PMs is presented that the reciprocal product of the transmission wrench screw matrix and the output twist screw matrix of PMs is a diagonal matrix, and all elements on the main diagonal are nonzero constants. The forms of the transmission wrench screws are determined by the criterion. Secondly, the forms of the actuated and unactuated screws can be obtained according to their relationships with the transmission wrench screws. The basic decoupled limbs are generated by combination of the above actuated and unactuated screws. Finally, a closed-loop units construction method is investigated to apply the decoupled mechanisms in a better way on the high stifness occasion. The closed-loop units are constructed in the basic decoupled limbs to generate a high-stifness fully decoupled 3T PM. Kinematic and stifness analyses show that the Jacobian matrix is a diagonal matrix, and the stifness is obviously higher than that of the coupling mechanisms, which verifes the correctness of the proposed synthesis method. The mechanism synthesized by this method has a good application prospect in vehicle durability test platform.

Improving physical properties of poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels via the Hofmeister effect

Hydrogel is a kind of three-dimensional crosslinked polymer material with high moisture content.However,due to the network defects of polymer gels,traditional hydrogels are usually brittle and fragile,which limits their practical applications.Herein,we present a Hofmeister effect-aided facile strategy to prepare high-performance poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels.Layered montmorillonite nanosheets can not only serve as crosslinking agents to enhance the mechanical properties of the hydrogel but also promote the ion conduction.More importantly,based on the Hofmeister effect,the presence of(NH_(4))_(2)SO_(4)can endow nanocomposite hydrogels with excellent mechanical properties by affecting PVA chains'aggregation state and crystallinity.As a result,the as-prepared nanocomposite hydrogels possess unique physical properties,including robust mechanical and electrical properties.The as-prepared hydrogels can be further assembled into a high-performance flexible sensor,which can sensitively detect large-scale and small-scale human activities.The simple design concept of this work is believed to provide a new prospect for developing robust nanocomposite hydrogels and flexible devices in the future.

挤压态和峰值时效态Mg−6Al−3Sn−2Zn合金显微组织与力学性能之间的关系

研究挤压态和时效态Mg−6Al−3Sn−2Zn(ATZ632)合金的显微组织和力学性能。挤压态ATZ632合金表现出优异的力学性能,其屈服强度(YS)、极限抗拉强度(UTS)和伸长率(EL)分别为216.4MPa、344.3MPa和18.4%。经时效处理后,Mg_(17)Al_(12)析出相体积分数增加且出现Mg_(4)Zn_(7)相,Mg_(17)Al_(12)相平行于基面,Mg4Zn7垂直于α-Mg的(0001)面析出,从而使时效态ATZ632合金的YS和UTS分别增加到252.5和416.2MPa;但EL下降至10.1%。经过150℃较低温度时效处理后,合金中出现静态再结晶晶粒,且静态再结晶晶粒的c轴垂直于挤压方向,其取向呈高度一致性。

Grain refinement and strength enhancement in Mg wrought alloys: A review

Low absolute strength becomes one major obstacle for the wider applications of low/no rare-earth(RE) containing Mg alloys. This review firstly demonstrates the importance of grain refinement in improving strength of Mg alloys by comprehensively comparing with other strategy, e.g., precipitation strengthening. Dynamic recrystallization(DRX) plays a crucial role in refining grain size of Mg wrought alloys.Therefore, secondly, the DRX models, grain nucleation mechanisms and the related grain refinement abilities in Mg alloys are summarized,including phase boundary, twin boundary and general boundary induced recrystallization. Thirdly, the newly developed low-RE containing Mg alloy, e.g., Mg-Ce, Mg-Nd and Mg-Sm based alloys, and the RE-free Mg alloys, e.g., Mg-Al, Mg-Zn, Mg-Sn and Mg-Ca based alloy,are reviewed, with the focus on enhancing the mechanical properties mainly via the grain refinement strategy. At the last section, the perspectives and outstanding issues concerning high-performance Mg wrought alloys are also proposed. This review is meant to promote the deep understanding on the critical role of grain refinement in Mg alloys and provide reference for the development of other high strength and low-cost Mg alloys which are fabricated by the conventional extrusion/rolling processing.

复杂基因组测序技术研究进展

复杂基因组指的是无法使用常规测序和组装手段直接解析的一类基因组,通常指包含高比例重复序列、高杂合度、极端GC含量、存在难消除异源DNA污染的基因组。为了解决复杂基因组的测序和组装问题,需要分别从基因组测序实验方法、测序技术平台、组装算法与策略3个方面进行深入研究。本文详细介绍了复杂基因组测序组装相关的现有技术与方法,并结合复杂基因组经典实例介绍了复杂基因组测序的技术解决途径和发展历程,可为制订合适的复杂基因组测序策略提供参考。

角膜保护剂对2型糖尿病患者白内障超声乳化术后眼表的影响

目的:探讨白内障超声乳化术中应用角膜保护剂(2%HPMC)对年龄相关性白内障(ARC)伴2型糖尿病患者术后眼表泪膜稳定性的影响。方法:前瞻性平行对照试验。将我院2017-03/2018-05行白内障超声乳化术的ARC伴2型糖尿病患者107例(107眼)纳入该研究。按照随机数字表将患者分为HPMC组和平衡盐溶液(BSS)组,HPMC组纳入57眼,术中角膜表面均匀覆盖2%HPMC;BSS组纳入50眼,术中不断向角膜上滴注BSS。所有患者手术前1d及术后7、30、60、90d行泪膜破裂时间(BUT)、泪液分泌试验(SⅠt)、角膜荧光素染色(CFS)检查,并观察其变化。结果:白内障术后7、30、60d,与BSS组术眼比较,HPMC组术眼BUT明显延长,且CFS着色点明显减少;术后7d,HPMC组SⅠt值明显低于BSS组,术后30、60d时HPMC组SⅠt值高于BSS组(P<0.05)。术后60d,HPMC组BUT、SⅠt、CFS结果与术前比较无差异(P>0.05),BSS组BUT、SⅠt、CFS结果与术前比较有差异(P<0.05)。结论:白内障超声乳化术中应用2%HPMC对ARC伴2型糖尿病患者眼表泪膜稳定性有一定保护作用,术后60d泪膜稳定性各项指标可恢复至术前水平。

缝合泡沫夹芯材料的冲击后压缩性能

利用VARTM制备技术制备缝合/未缝合泡沫夹芯材料,分别在4组不同冲击能量下进行冲击试验及冲击后压缩试验,利用超声c检测技术对冲击后纤维面板内部的不可见损伤进行探测,发现缝合树脂柱的加入可以有效提高复合结构的抗冲击性能,其中冲击最大载荷的提升幅度达到20%~50%,此时,通过超声c检测发现纤维面板内部已经发生了较多的基体开裂,但分层破坏及纤维断裂情况有明显的减少,另外冲击后剩余压缩强度的提高也达到了35%~40%,同时发现相较于15 mm×15 mm的缝合密度,10 mm×10 mm的缝合密度具有更好的抗冲击性能。

Catalytic roles of the acid sites in different pore channels of H‐ZSM‐5 zeolite for methanol‐to‐olefins conversion

H‐ZSM‐5 zeolite is a typical catalyst for methanol‐to‐olefins(MTO)conversion.Although the performance of zeolite catalysts for MTO conversion is related to the actual location of acid sites in the zeolite framework,the catalytic roles of the acid sites in different pore channels of the H‐ZSM‐5 zeolite are not well understood.In this study,the MTO reaction network,involving the aromatic cycle,alkene cycle,and aromatization process,and also the diffusion behavior of methanol feedstock and olefin and aromatic products at different acid sites in the straight channel,sinusoidal channel,and intersection cavity of H‐ZSM‐5 zeolite was comparatively investigated using density functional theory calculations and molecular dynamic simulations.The results indicated that the aromatic cycle and aromatization process occurred preferentially at the acid sites in the intersection cavities with a much lower energy barrier than that at the acid sites in the straight and sinusoidal channels.In contrast,the formation of polymethylbenzenes was significantly suppressed at the acid sites in the sinusoidal and straight channels,whereas the alkene cycle can occur at all three types of acid sites with similar energy barriers and probabilities.Consequently,the catalytic performance of H‐ZSM‐5 zeolite for MTO conversion,including activity and product selectivity,can be regulated properly through the purposive alteration of the acid site distribution,viz.,the location of Al in the zeolite framework.This study helps to elucidate the relation between the catalytic performance of different acid sites in the H‐ZSM‐5 zeolite framework for MTO conversion,which should greatly benefit the design of efficient catalyst for methanol conversion.

Effects of IBA on the rooting of branch cuttings of Chinese jujube (Zizyphus jujuba Mill.) and changes to nutrients and endogenous hormones

‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.

The apricot(Prunus armeniaca L.)genome elucidates Rosaceae evolution and beta-carotenoid synthesis

Apricots,scientifically known as Prunus armeniaca L,are drupes that resemble and are closely related to peaches or plums.As one of the top consumed fruits,apricots are widely grown worldwide except in Antarctica.A high-quality reference genome for apricot is still unavailable,which has become a handicap that has dramatically limited the elucidation of the associations of phenotypes with the genetic background,evolutionary diversity,and population diversity in apricot.DNA from P.armeniaca was used to generate a standard,size-selected library with an average DNA fragment size of~20 kb.The library was run on Sequel SMRT Cells,generating a total of 16.54 Gb of PacBio subreads(N50=13.55 kb).The high-quality P.armeniaca reference genome presented here was assembled using long-read single-molecule sequencing at approximately 70×coverage and 171×Illumina reads(40.46 Gb),combined with a genetic map for chromosome scaffolding.The assembled genome size was 221.9 Mb,with a contig NG50 size of 1.02 Mb.Scaffolds covering 92.88%of the assembled genome were anchored on eight chromosomes.Benchmarking Universal Single-Copy Orthologs analysis showed 98.0%complete genes.We predicted 30,436 protein-coding genes,and 38.28%of the genome was predicted to be repetitive.We found 981 contracted gene families,1324 expanded gene families and 2300 apricot-specific genes.The differentially expressed gene(DEG)analysis indicated that a change in the expression of the 9-cis-epoxycarotenoid dioxygenase(NCED)gene but not lycopene beta-cyclase(LcyB)gene results in a lowβ-carotenoid content in the white cultivar“Dabaixing”.This complete and highly contiguous P.armeniaca reference genome will be of help for future studies of resistance to plum pox virus(PPV)and the identification and characterization of important agronomic genes and breeding strategies in apricot.