Fluid-chemical modeling of the near-cathode sheath formation process in a high current broken in DC air circuit breaker

When the contacts of a medium-voltage DC air circuit breaker(DCCB) are separated, the energy distribution of the arc is determined by the formation process of the near-electrode sheath. Therefore, the voltage drop through the near-electrode sheath is an important means to build up the arc voltage, which directly determines the current-limiting performance of the DCCB. A numerical model to describe the near-electrode sheath formation process can provide insight into the physical mechanism of the arc formation, and thus provide a method for arc energy regulation. In this work, we establish a two-dimensional axisymmetric time-varying model of a medium-voltage DCCB arc when interrupted by high current based on a fluid-chemical model involving 16 kinds of species and 46 collision reactions. The transient distributions of electron number density, positive and negative ion number density, net space charge density, axial electric field, axial potential between electrodes, and near-cathode sheath are obtained from the numerical model. The computational results show that the electron density in the arc column increases, then decreases, and then stabilizes during the near-cathode sheath formation process, and the arc column's diameter gradually becomes wider. The 11.14 V–12.33 V drops along the17 μm space charge layer away from the cathode(65.5 k V/m–72.5 k V/m) when the current varies from 20 k A–80 k A.The homogeneous external magnetic field has little effect on the distribution of particles in the near-cathode sheath core,but the electron number density at the near-cathode sheath periphery can increase as the magnetic field increases and the homogeneous external magnetic field will lead to arc diffusion. The validity of the numerical model can be proven by comparison with the experiment.

碳储科学与工程新专业建设模式探索与发展方向思考

建设碳储科学与工程新专业,培养新型碳储人才,是国家战略需求和新时代育人要求。通过分析研究,提出以行业需求为导向,以人才培养为目标,制订地学特色培养方案;以课程建设为中心,以教材编写为主体,构建现代化教学资源数据库;以教学名师为引领,以队伍建设为抓手,组建老中青结合优秀教学团队;以实验室建设为依托,以虚实结合为手段,建设室内室外实验教学新平台;以科研合作为契机,以工程实践为主题,打造校企合作实践教学新基地的五措施并举、五内容并建的专业建设方案。提出了集教学创新团队、精品课程、品牌教材、特色实践教学基地于一体的碳储科学与工程专业建设模式。碳储科学与工程专业建设理念、教学方法、课程体系及应用成果将对同行专业具有借鉴作用。

塔里木盆地北部下寒武统肖尔布拉克组海进-海退转换背景下的微生物礁滩发育模式

基于塔里木盆地西北缘阿克苏地区的野外露头观察和北部地区重点探井的测井资料分析和薄片鉴定工作,建立塔里木盆地塔北地区的高精度层序地层格架,分析肖尔布拉克组碳酸盐岩台地的演化过程及微生物礁滩发育模式。研究认为肖尔布拉克组可分为2个三级层序(SQ1和SQ2)和5个四级层序(sq1、sq2、sq3、sq4和sq5),其中sq1和sq2发育层状微生物席,为中-内缓坡沉积,对应缓坡型台地;sq3时期相对海平面先上升后下降,缓坡型台地转变为弱镶边台地,在古地貌高地微生物开始建礁,古地貌较低的斜坡区微生物岩基本不发育;sq4和sq5时期海平面持续下降,弱镶边台地发育,sq4发育藻粒滩和微生物礁沉积,sq5发育砂屑滩、砾屑滩和微生物礁沉积。高精度层序地层对比结果显示海平面的变化在垂向上控制着微生物礁滩的演化特征,古地貌在平面上控制着微生物礁滩的分布。

The Solar Upper Transition Region Imager(SUTRI)Onboard the SATech-01 Satellite

The Solar Upper Transition Region Imager(SUTRI)onboard the Space Advanced Technology demonstration satellite(SATech-01),which was launched to a Sun-synchronous orbit at a height of~500 km in 2022 July,aims to test the on-orbit performance of our newly developed Sc/Si multi-layer reflecting mirror and the 2k×2k EUV CMOS imaging camera and to take full-disk solar images at the Ne VII 46.5 nm spectral line with a filter width of~3 nm.SUTRI employs a Ritchey-Chrétien optical system with an aperture of 18 cm.The on-orbit observations show that SUTRI images have a field of view of~416×416 and a moderate spatial resolution of~8″without an image stabilization system.The normal cadence of SUTRI images is 30 s and the solar observation time is about16 hr each day because the earth eclipse time accounts for about 1/3 of SATech-01's orbit period.Approximately15 GB data is acquired each day and made available online after processing.SUTRI images are valuable as the Ne VII 46.5 nm line is formed at a temperature regime of~0.5 MK in the solar atmosphere,which has rarely been sampled by existing solar imagers.SUTRI observations will establish connections between structures in the lower solar atmosphere and corona,and advance our understanding of various types of solar activity such as flares,filament eruptions,coronal jets and coronal mass ejections.

Genome-wide profiling of histone H3 lysine 27 trimethylation and its modification in response to chilling stress in grapevine leaves

Histone H3 lysine 27 trimethylation(H3K27me3) is a histone modification associated with transcriptional repression. However, insights into the genome-wide pattern of H3K27me3 in grapevines are limited. Here, anti-H3K27 chromatin immunoprecipitation(ChIP), high-throughput sequencing, and transcriptome analysis were performed using leaves of Vitis amurensis. The leaves were treated at 4°C for 2 h and 24 h and used to investigate changes in H3K27me3 under chilling treatment. The results show that H3K27me3 is well-distributed both in gene regions(-50%) and in the intergenic region(-50%) in the grapevine genome(Vitis vinifera ‘Pinot Noir PN40024'). H3K27me3 was found to be localized in8 368 annotated gene regions in all detected samples(leaves at normal temperature and under chilling treatments) and mainly enriched in gene bodies with the adjacent promoter and downstream areas. The short-term chilling treatments(4°C for 2 h) induced 2 793 gains and 305losses in H3K27me3 modification. Subsequently, 97.3% of the alterations were restored to original levels after 24 h treatment. The ChIP-qPCR for five differential peaks showed similar results to the data for ChIP-seq, indicating that the chilling-induced H3K27me3 modification is reliable.Integrative analysis of transcriptome and ChIP-seq results showed that the expression of H3K27me3 target genes was significantly lower than those of non-target genes, indicating transcriptional repression of H3K27me3 in grapevine leaves. Furthermore, histone methylation alterations were detected in 82 genes and were related to either repression or activation of their expression during chilling stress. The findings provide the genome-wide H3K27me3 patterns in grapevines and shed light on uncovering its regulation in chilling stress responses.

VvBBX44 and VvMYBA1 form a regulatory feedback loop to balance anthocyanin biosynthesis in grape

Anthocyanins are essential for the quality of perennial horticultural crops,such as grapes.In grapes,ELONGATED HYPOCOTYL 5(HY5)and MYBA1 are two critical transcription factors that regulate anthocyanin biosynthesis.Our previous work has shown that Vitis vinifera B-box protein 44(VvBBX44)inhibits anthocyanin synthesis and represses VvHY5 expression in grape calli.However,the regulatory mechanism underlying this regulation was unclear.In this study,we found that loss of VvBBX44 function resulted in increased anthocyanin accumulation in grapevine callus.VvBBX44 directly represses VvMYBA1,which activates VvBBX44.VvMYBA1,but not VvBBX44,directly modulates the expression of grape UDP flavonoid 3-O-glucosyltransferase(VvUFGT).We demonstrated that VvBBX44 represses the transcriptional activation of VvUFGT and VvBBX44 induced by VvMYBA1.However,VvBBX44 and VvMYBA1 did not physically interact in yeast.The application of exogenous anthocyanin stimulated VvBBX44 expression in grapevine suspension cells and tobacco leaves.These findings suggest that VvBBX44 and VvMYBA1 form a transcriptional feedback loop to prevent overaccumulation of anthocyanin and reduce metabolic costs.Our work sheds light on the complex regulatory network that controls anthocyanin biosynthesis in grapevine.

Grapevine plantlets respond to different monochromatic lights by tuning photosynthesis and carbon allocation

The quality of planting materials is the foundation for productivity,longevity,and berry quality of perennial grapevines with a long lifespan.Manipulating the nursery light spectrum may speed up the production of healthy and high-quality planting vines but the underlying mechanisms remain elusive.Herein,the effects of different monochromatic lights(green,blue,and red)on grapevine growth,leaf photosynthesis,whole-plant carbon allocation,and transcriptome reprograming were investigated with white light as control.Results showed that blue and red lights were favorable for plantlet growth in comparison with white light.Blue light repressed excessive growth,significantly increased the maximum net photosynthetic rate(Pn)of leaves by 39.58%and leaf specific weight by 38.29%.Red light increased the dry weight of the stem by 53.60%,the starch content of the leaf by 53.63%,and the sucrose content of the stem by 230%.Green light reduced all photosynthetic indexes of the grape plantlet.Photosynthetic photon flux density(PPFD)/Ci–Pn curves indicated that blue light affected photosynthetic rate depending on the light intensity and CO2 concentration.RNA-seq analysis of different organs(leaf,stem,and root)revealed a systematic transcriptome remodeling and VvCOP1(CONSTITUTIVELY PHOTOMORPHOGENIC 1),VvHY5(ELONGATED HYPOCOTYL5),VvHYH(HY5 HOMOLOG),VvELIP(early light-induced protein)and VvPIF3(PHYTOCHROME INTERACTING FACTOR 3)may play important roles in this shoot-to-root signaling.Furthermore,the correlation network between differential expression genes and physiological traits indicated that VvpsbS(photosystem II subunit S),Vvpsb28(photosystem II subunit 28),VvHYH,VvSUS4(sucrose synthase 4),and VvALDA(fructose-bisphosphate aldolase)were pertinent candidate genes in responses to different light qualities.Our results provide a foundation for optimizing the light recipe of grape plantlets and strengthen the understanding of light signaling and carbon metabolism under different monochromatic lights.

The class B heat shock factor HSFB1 regulates heat tolerance in grapevine

Grape is a widely cultivated crop with high economic value.Most cultivars derived from mild or cooler climates may not withstand increasing heat stress.Therefore,dissecting the mechanisms of heat tolerance in grapes is of particular significance.Here,we performed comparative transcriptome analysis of Vitis davidii‘Tangwei’(heat tolerant)and Vitis vinifera‘Jingxiu’(heat sensitive)grapevines after exposure to 25°C,40°C,or 45°C for 2 h.More differentially expressed genes(DEGs)were detected in‘Tangwei’than in‘Jingxiu’in response to heat stress,and the number of DEGs increased with increasing treatment temperatures.We identified a class B Heat Shock Factor,HSFB1,which was significantly upregulated in‘Tangwei’,but not in‘Jingxiu’,at high temperature.VdHSFB1 from‘Tangwei’and VvHSFB1 from‘Jingxiu’differ in only one amino acid,and both showed similar transcriptional repression activities.Overexpression and RNA interference of HSFB1 in grape indicated that HSFB1 positively regulates the heat tolerance.Moreover,the heat tolerance of HSFB1-overexpressing plants was positively correlated to HSFB1 expression level.The activity of the VdHSFB1 promoter is higher than that of VvHSFB1 under both normal and high temperatures.Promoter analysis showed that more TATA-box and AT∼TATA-box cis-elements are present in the VdHSFB1 promoter than the VvHSFB1 promoter.The promoter sequence variations between VdHSFB1 and VvHSFB1 likely determine the HSFB1 expression levels that inf luence heat tolerance of the two grape germplasms with contrasting thermotolerance.Collectively,we validated the role of HSFB1 in heat tolerance,and the knowledge gained will advance our ability to breed heat-tolerant grape cultivars.

塔里木盆地良里塔格地区奥陶系生物礁的沉积特征和成礁模式

塔里木盆地奥陶系生物礁储集层受到广泛关注。笔者优选塔里木盆地良里塔格地区奥陶系鹰山组顶部生物礁体(NYG-1)和一间房组底部生物礁体(NYG-2)为研究对象,通过详细的野外观察、实测和薄片鉴定,对生物礁的生物类型、岩性特征和沉积相单元进行分析。结果表明:塔里木盆地良里塔格地区鹰山组和一间房组的造礁生物主要由瓶筐石组成,与生物礁相关的岩性有障积礁灰岩、粘结礁灰岩、生屑粒泥灰岩、生屑泥粒灰岩、内碎屑泥粒灰岩、生屑颗粒灰岩、内碎屑颗粒灰岩和球粒颗粒灰岩。NYG-1礁体发育礁基、礁核、礁顶、礁翼和礁盖5个沉积相单元;NYG-2发育礁基、礁核与礁盖3个沉积相单元。从生物类型来看,鹰山组的礁为托盘—障积礁,为近似圆形的台内点礁,展布无明显的方向性;一间房组的礁为托盘障积—粘结礁,属台缘礁,常呈现出礁体迁移的特征。鹰山组和一间房组成礁模式的共同点是都经历了礁基的形成、礁体的发育和礁体的衰亡3个阶段,而差异主要表现在生物礁体的灭亡阶段:对鹰山组生物礁而言,海平面的快速下降和高能水动力条件导致了瓶筐石的灭亡和内碎屑灰岩的产生;对一间房组生物礁而言,海平面的上升和浮游藻类生物大量发育造成造礁生物甁筐石的灭亡。以上研究对于建立符合塔里木盆地地区条件的礁体沉积模式和探索露头与井下生物礁对比研究有重要意义。

Agrobacterium tumefaciens-Mediated Transformation of Wild Tobacco Species Nicotiana debneyi, Nicotiana clevelandii, and Nicotiana glutinosa

Studies on Agrobacterium tumefaciens-mediated transformation of wild tobaccos Nicotiana debneyi, Nicotiana clevelandii, and Nicotiana glutinosa were conducted. Leaf disks were infected and co-cultivated with A. tumefaciens strain EHA105 carrying the binary vector pBISN1 with an intron interrupted β-glucuronidase (GUS) reporter gene (gusA) and the neomycin phosphotransferase gene (nptII). Selection and regeneration of kanamycin resistant shoots were conducted on regeneration medium containing 8.88 μM 6-benzylaminopurine (BAP), 0.57 μM indole-3-acetic acid (IAA), 50 mg·L-1 kanamycin and 250 mg·L-1 timentin. Kanamycin resistant shoots were rooted Murashige and Skoog (MS) medium containing 100 mg·L-1 kanamycin and 250 mg·L-1 timentin. Using this protocol, kanamycin-resistant plants were obtained from all three wild tobaccos at frequencies of 75.6% for N. debneyi, 25.0% for N. clevelandii, and 2.8% for N. glutinosa. Transcripts of nptII and gusA were detected in kanamycin-resistant T0 transformants (i.e., 2 for N. glutinosa and 5 for each of the N. debneyi and N. clevelandii) by the reverse transcript polymerase chain reaction (RT-PCR), and histochemical GUS assays confirmed expression of gusA in both T0 plants and T1 seedlings. The results indicate that the protocols are efficient for transformation of wild tobacco N. debneyi and N. clevelandii.

塔里木盆地寒武系中统—上统不整合面识别特征及地质意义——以肖尔布拉克剖面为例

采用野外露头观察,薄片分析,主、微量元素测试及碳氧同位素测试等方法,结合层序地层学理论,以塔里木盆地柯坪地区肖尔布拉克剖面为例,分析寒武系中统—上统T81不整合面识别特征及地质意义。结果表明:在露头上,T81界面表现为岩相转换面,界面上发育中厚层状藻砂屑白云岩,界面下可见溶塌角砾,岩性为泥晶灰岩—中厚层白云岩—含叠层石藻白云岩的有序叠加。Ce、La、Al、Fe、Si等质量分数在界面处明显增大,即惰性元素相对富集;Cl的质量分数在界面上突减,反映界面下盐度较大;Sr/Ba和Mg/Ca变小,反映水体变浅;δ13 C在界面附近减小,界面下δ13 C较大,δ18 O明显降低,指示海平面下降造成短期暴露,且界面下的阿瓦塔格组沉积水介质盐度较高,还原条件下富δ12 C的有机质快速埋藏。T81界面下U、Th、K质量分数增加,GR曲线值较大,反映界面下泥质含量较大,界面上沉积环境发生变化,界面存在陆上短期暴露。地震剖面上可见顶超、前积特征,代表沉积间断的发育。T81界面属于Ⅱ级层序界面,在全盆地范围内发育,主要表现为同沉积暴露不整合、平行不整合、构造—侵蚀不整合、多期叠加不整合。界面上、下发育两套性质不同的断裂体系,沉积环境由缓坡型蒸发台地转变为镶边型局限台地。该研究结果为塔里木盆地寒武系沉积环境分析、储盖组合预测提供参考。

昆明城市热岛效应的数值模拟研究

本文利用WRF(V3.9.1)模式中耦合Noah/SLUCM方案作为Control试验,研究了土地利用类型(Md04试验)、陆面过程(NoUCM试验)和湖泊(Nolake试验)对城市热岛强度及昆明城市气象要素水平、垂直的时空分布影响。主要结论如下:(1)四个试验城市热岛强度的平均日变化趋势相似,白天城市热岛强度较弱、夜间较强,在20时(北京时,下同)左右达到最大值。城市冠层(湖泊)对城市热岛有较明显的减(增)温,Control-NoUCM(Nolake)试验中,平均日最大差值为−0.79°C(+1.07°C)。(2)从能量平衡方程分析Control-Md04试验,感热(潜热)通量的差值为+46.18(−79.71)W m^(−2),潜热通量释放大于感热通量的绝对值。Control-NoUCM试验中,感热(潜热)通量的差值为−40.88(+29.60)W m^(−2);因NoUCM试验未考虑几何建筑物储热与遮挡,太阳辐射大部分被地表所吸收,导致感热通量偏大。(3)四种试验中,15(07)时边界层高度达到最大(小)值。NoUCM(Nolake)试验中城市边界层高度分别降低103 m(32 m)左右,而Md04试验中城市边界层高度增加102 m左右。(4)湖泊(滇池)对城市热岛环流影响的试验表明,湖泊上空垂直运动较弱,但水平方向湖陆风较大,这有利于向城市输送水汽,增加干空气湿度,使城市中空气的水汽含量增加,同时增大潜热能量释放,降低感热通量,减小了垂直温度梯度。

新疆塔北隆起桥古地区前中生界碳酸盐岩潜山储层特征与发育模式

桥古地区前中生界潜山地层是新疆塔北隆起油气勘探取得突破的重点区域。该区潜山地层埋藏深且分布复杂,储层非均质性强且受后期流体活动改造强烈,油气富集规律不清楚,严重制约区域油气勘探和靶区优选。为查明潜山储层特征和储层发育主控因素,建立储层发育模式,利用岩心、钻测井和地震等资料进行系统的储层特征和控制因素研究。研究结果表明:桥古地区前中生界储层岩性主要为晶粒白云岩、硅质白云岩及颗粒白云岩三大类;储集空间以裂缝为主,溶孔次之,局部发育溶洞。不同岩相物性差异明显,细粉晶白云岩、灰质粉晶白云岩和砂屑泥晶白云岩储集层较发育,储层基质物性好;泥晶白云岩、硅质白云岩相对致密,为非储层,物性差。基于以上研究提炼出桥古地区内幕潜山储层发育模式,即储层发育主要受控于岩相、断裂及埋藏-热液作用,其中岩相是储层发育的物质基础,断裂是储层发育的关键因素,埋藏-热液对储层发育进行叠加改造。对比目的层系储集单元特征,肖尔布拉克组上段发育5套开发小层系,其中第1、3、4套开发层系具有良好的储层物性和储盖组合,是未来油气勘探与靶区优选重点目标。

Design of the Full-disk Magneto Graph (FMG) onboard the ASO-S

The Full-disk Magneto Graph(FMG),a payload onboard the Advanced Space Solar Observatory(ASO-S),will measure the vector magnetic field in the photosphere.The instrument consists of a frontwindow filter,a telescope,an LCVR polarimeter,an image-stabilization system,a seven-stage tunable Lyot filter,a CMOS camera with 4096×4096 pixels and a pair of calibration/focus wheels.In this paper,we describe the design of the FMG instrument and provide a summary of test observations carried out with the FMG prototype.

Preparation,Microstructure and Properties of NiO-Cr_2O_3-TiO_2 Infrared Radiation Coating

The spherical agglomerated particles were fabricated by spray drying with the powders of NiO, Cr2O3 and TiO2. Plasma spray power, which has good property of flowability, was acquired by heat treatment from the particles at 1200℃ in the reducing atmosphere. Dark and uniform coating of More than 50 μm thick was deposited on the copper sheet substrate by plasma spraying. It is found that the infrared normal total emissivity of the coating is up to 0.91 at 600℃ by infrared radiation testing. The X-ray diffraction analysis shows that the formation of （Cr0.88Ti0.12）2O3 and spinel structural NiCr2O4 in the coating is the main reason for high efficient infrared radiation, and the phase structure and performance of coating is favorable under the thermal cycle between room temperature and 600℃.

Optimizing the CRISPR/Cas9 system for genome editing in grape by using grape promoters

The efficacy of the CRISPR/Cas9 system in grapevine(Vitis vinifera L.)has been documented,but the optimization of this system,as well as CRISPR/Cas9-mediated multiplex genome editing,has not been explored in this species.Herein,we identified four VvU3 and VvU6 promoters and two ubiquitin(UBQ)promoters in grapevine and demonstrated that the use of the identified VvU3/U6 and UBQ2 promoters could significantly increase the editing efficiency in grape by improving the expression of sgRNA and Cas9,respectively.Furthermore,we conducted multiplex genome editing using the optimized CRISPR/Cas9 vector that contained the conventional multiple sgRNA expression cassettes or the polycistronic tRNA-sgRNA cassette(PTG)by targeting the sugar-related tonoplastic monosaccharide transporter(TMT)family members TMT1 and TMT2,and the overall editing efficiencies were higher than 10%.The simultaneous editing of TMT1 and TMT2 resulted in reduced sugar levels,which indicated the role of these two genes in sugar accumulation in grapes.Moreover,the activities of the VvU3,VvU6,and UBQ2 promoters in tobacco genome editing were demonstrated by editing the phytoene desaturase(PDS)gene in Nicotiana benthamiana leaves.Our study provides materials for the optimization of the CRISPR/Cas9 system.To our knowledge,our simultaneous editing of the grape TMT family genes TMT1 and TMT2 constitutes the first example of multiplex genome editing in grape.The multiplex editing systems described in this manuscript expand the toolbox of grape genome editing,which would facilitate basic research and molecular breeding in grapevine.

Temperature field simulations during selective laser melting process based on fully threaded tree

Selective laser melting(SLM) is a promising technique for additive manufacturing. During SLM of metallic powder, the temperature field and thermal history are important to understand physical phenomena involved. The purpose of this study is to simulate the temperature field during the SLM process of a hollow cylinder shape part based on a fully threaded tree(FTT) technique, and to analyze the temperature variation with time in different regions of the part. A revised model for temperature field simulation in the SLM process was employed, which includes the transition of powder-to-dense sub-model and a moving volumetric Gaussian distribution heat source sub-model. The FTT technique is then adopted as an adaptive mesh strategy in the simulation. The simulation result shows that during the SLM process of cylinder part, the temperature of inner powder bed is obviously higher than external one. The temperature at the internal of the molten pool is also higher than external, which may lead to differences in microstructures and other properties between the two regions.

Distributed Cooperative OFDM-IM System

This paper considered a multi-relay distributed cooperative system in which not only the source communicates with the destination,but also the relays have communication requests with the destination.In order to achieve the requirements of simultaneous communication for the source and relays,we propose a distributed cooperative system based on orthogonal frequency division multiplexing with index modulation(OFDM-IM).In this system,the relay can communicate with the destination by superimposing its own signal over the inactive subcarriers on the decoded OFDM-IM signal.Upper bounds on the bit error rates of the source and the active relay are both derived in closed form,whose tightness is verified through simulation results.

A Near Optimal Power Allocation Scheme for Cooperative Relay Networking with NOMA

In this paper, we propose cooperative relay networks with non-orthogonal multiple access in order to design a near-optimal power allocation strategy. Like other next generation wireless technologies, spatially multiplexed transmissions are achieved by relay nodes which enables decode-and-forward relaying of a new superposition code after reception from the source. It is worth noting that, since it is hard to exactly prove the proposed PA scheme, due the fact that it is one kind of the approximate conjectures. Therefore, mathematical and numerical methods have been used to clarify the feasibility of the proposal. Numerical results indicate that it is able to asymptotically achieve the optimal sum rate at the higher signal-to-noise ratio region with the proposed strategy applied instead of negligible performance loss.

Quantitative Survivability Analysis Using Probability Model Checking: A Study of Cluster-Based Vehicle Networks with Dual Cluster Heads

As an important part of future 5G wireless networks,a vehicular network demands safety,reliability and connectivity.In this context,networking survivability is usually considered an important metric to evaluate network performance.In this paper,we propose a survivability model for vehicle communication networking based on dual cluster heads,wherein a backup cluster head(CH)will be activated if the primary CH fails,thereby effectively enhancing the network lifetime.Additionally,we introduce a software rejuvenation strategy for the prime CH to further improve the survivability of the entire network.Using the Probabilistic Symbolic Model Checker(PRISM),we verify and discuss the proposed survivability model via numerical simulations.The results show that network survivability can be effectively improved by introducing an additional CH and further enhanced by adopting the software rejuvenation technique.