A geochemical perspective on the genesis of Cenozoic basic volcanism in northeastern Turkey:an overview of metasomatism and heterogeneity of the sub-continental lithospheric mantle in a post-collisional setting

The post-collisional Cenozoic basic volcanic rocks in NE Turkey show temporal variations in whole-rock lithophile element and highly siderophile element(HSE)systematics that are mainly associated with the nature of sub-continental lithospheric mantle(SCLM)sources and parental melt generation.So far,the traditional whole-rock lithophile geochemical data of these basic volcanic rocks have provided important constraints on the nature of SCLM sources.Integrated lithophile element and HSE geochemical data of these basic volcanic rocks also reveal the heterogeneity of the SCLM source,which is principally related to variable metasomatism resulting from previous subduction(s)and post-collisional mantle-crust interactions in an extensional setting.Lithophile element geochemical features suggest that the parental magmas have derived from metasomatized spinel-to garnet-bearing SCLM sources for Eocene and Miocene basic volcanic rocks with subduction signatures whereas originated from spinel-to garnet-bearing SCLM sources for Mio-Pliocene and Plio-Quaternary basaltic volcanic rocks without the subduction signature.Lithophile element and HSE geo-chemistry also reveal that Eocene and Miocene basic vol-canic rocks were affected by more pronounced crustal contamination than the basaltic volcanic rocks of Mio-Pliocene and Quaternary.Furthermore,the integrated lithophile element and HSE compositions of these basic volcanic rocks,together with the regional asymmetric lithospheric delamination model,reveal that the compositional variation(especially due to metasomatism)was significant temporally in the heterogeneity of the SCLM sources from which parental magmas formed during the Cenozoic era.

Wind-Vortex-Induced Vibrations of a Deepwater Jacket Pipe and Vibration Suppression Using a Nonlinear Energy Sink

The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.

Dynamic performance and parameter optimization of a half-vehicle system coupled with an inerter-based X-structure nonlinear energy sink

Inspired by the demand of improving the riding comfort and meeting the lightweight design of the vehicle, an inerter-based X-structure nonlinear energy sink(IXNES) is proposed and applied in the half-vehicle system to enhance the dynamic performance. The X-structure is used as a mechanism to realize the nonlinear stiffness characteristic of the NES, which can realize the flexibility, adjustability, high efficiency, and easy operation of nonlinear stiffness, and is convenient to apply in the vehicle suspension, and the inerter is applied to replacing the mass of the NES based on the mass amplification characteristic. The dynamic model of the half-vehicle system coupled with the IX-NES is established with the Lagrange theory, and the harmonic balance method(HBM) and the pseudo-arc-length method(PALM) are used to obtain the dynamic response under road harmonic excitation. The corresponding dynamic performance under road harmonic and random excitation is evaluated by six performance indices, and compared with that of the original half-vehicle system to show the benefits of the IX-NES. Furthermore, the structural parameters of the IX-NES are optimized with the genetic algorithm. The results show that for road harmonic and random excitation, using the IX-NES can greatly reduce the resonance peaks and root mean square(RMS) values of the front and rear suspension deflections and the front and rear dynamic tire loads, while the resonance peaks and RMS values of the vehicle body vertical and pitching accelerations are slightly larger.When the structural parameters of the IX-NES are optimized, the vehicle body vertical and pitching accelerations of the half-vehicle system could reduce by 2.41% and 1.16%,respectively, and the other dynamic performance indices are within the reasonable ranges.Thus, the IX-NES combines the advantages of the inerter, X-structure, and NES, which improves the dynamic performance of the half-vehicle system and provides an effective option for vibration attenuation in the vehicle engineering.

Dynamics and vibration reduction performance of asymmetric tristable nonlinear energy sink

With its complex nonlinear dynamic behavior,the tristable system has shown excellent performance in areas such as energy harvesting and vibration suppression,and has attracted a lot of attention.In this paper,an asymmetric tristable design is proposed to improve the vibration suppression efficiency of nonlinear energy sinks(NESs)for the first time.The proposed asymmetric tristable NES(ATNES)is composed of a pair of oblique springs and a vertical spring.Then,the three stable states,symmetric and asymmetric,can be achieved by the adjustment of the distance and stiffness asymmetry of the oblique springs.The governing equations of a linear oscillator(LO)coupled with the ATNES are derived.The approximate analytical solution to the coupled system is obtained by the harmonic balance method(HBM)and verified numerically.The vibration suppression efficiency of three types of ATNES is compared.The results show that the asymmetric design can improve the efficiency of vibration reduction through comparing the chaotic motion of the NES oscillator between asymmetric steady states.In addition,compared with the symmetrical tristable NES(TNES),the ATNES can effectively control smaller structural vibrations.In other words,the ATNES can effectively solve the threshold problem of TNES failure to weak excitation.Therefore,this paper reveals the vibration reduction mechanism of the ATNES,and provides a pathway to expand the effective excitation amplitude range of the NES.

Q355NE钢特厚板坯凝固过程模拟研究

以(475×2000)mm断面的Q355NE钢特厚板坯为研究对象,通过射钉法和红外测温方法测量凝壳厚度及表面温度,将其作为凝固模型计算结果的验证。使用ProCAST软件进行凝固传热过程模拟,分析了不同拉速、过热度、比水量对铸坯温度场和凝固终点的影响规律。结果表明:与过热度和比水量的影响相比,拉速对其凝固终点、温度场影响较大,拉速每提高0.05 m/min,凝固终点平均后移4.54 m,铸坯完全凝固后的铸坯心部温度升高81℃左右;而比水量每降低10%,铸坯凝固终点后移0.33 m左右;过热度每升高5℃,铸坯凝固终点后移0.38 m左右。

路博润:扩充TPU生产线、成立亚太区高性能膜品创新中心、推出“ESTANE TPU赋能生态系统”

路博润公司近日宣布一系列加速拓展本地化生产和创新能力的重要举措,旨在进一步深化热塑性聚氨酯(TPU)业务本土发展布局。这包括扩充上海工厂TPU生产线、成立亚太区高性能膜品创新中心以及推出“ESTANE TPU赋能生态系统”。这些举措不仅凸显了路博润在TPU领域的雄厚实力,更彰显了对中国市场持续增长的坚定信心,以及对与行业共同成长的长期承诺。

1500MW燃机电站配套NE余热锅炉大型模块吊装工艺探讨

通过对国际上1500MW燃机电站配套NE余热锅炉大模块吊装工艺研究与实践,总结经验与不足,改进该类型余热锅炉大模块的吊装工艺,对未来类似项目提供积极参考。

路博润面向全球漆面保护膜市场推出ESTANE TPU赋能生态系统

前不久,路博润面向漆面保护膜(PPF)行业推出ESTANE TPU赋能生态系统,旨在帮助使用100% ESTANE TPU材料生产热塑性聚氨酯(TPU)基膜或PPF产品的制造商和品牌商们推广其产品的高品质和性能。路博润的ESTANE TPU在PPF行业拥有超过30年的应用经验,赢得了行业性能标杆的声誉。路博润的赋能生态系统为加入该系统的合作企业提供了源头材料的授权认证方式。

TDM网主用汇聚节点NE20故障案例分析

NE20作为各地区局广泛使用的重要路由汇聚设备,需要满足长期稳定运行的要求,本文结合湖北空管分局TDM网主用汇聚节点NE20发生的故障,TDM网承载的甚高频、雷达、ADS-B和甚高频监控业务出现短暂中断的现象,通过详细的排查过程,原因分析和改进措施,成功定位故障源头并提出有效的解决方案。

血清GABA、BDNF、5-HT、DA及NE在胃食管反流病中的表达及临床意义

目的探讨血清γ-氨基丁酸(GABA)、脑源性营养因子(BDNF)、5-羟色胺(5-HT)、去甲肾上腺素(NE)及多巴胺(DA)在胃食管反流病(GERD)中的表达及临床意义。方法选取100例GERD患者作为GERD组、40例同期健康体检者为对照组,GERD组患者给予药物治疗8周,根据治疗效果分为效果良好组和效果不良组;对照组于体检时、GERD组于治疗前、治疗后(8周时)取外周静脉血,检测血清GABA、BDNF、5-HT、DA、NE、胃动素(MTL)、胃泌素(GAS)、胆囊收缩素(CCK)水平;采用匹兹堡睡眠质量指数(PSQI)、汉密尔顿抑郁量表(HAMD)、焦虑自评量表(SAS)、日常生活能力量表(ADL)评分评估GERD组治疗前后、对照组体检时的睡眠质量、抑郁程度、焦虑状态、日常生活能力;比较GERD患者治疗前后、效果良好及效果不良组食管括约压力、立位返流时间比、卧位反流时间比、总反流时间;采用Pearson分析GERD患者治疗前GABA、BDNF、5-HT、NE及DA水平与患者食管括约肌压力、立位返流时间比、卧位返流时间比、总返流时间比、MTL、GAS、CCK的相关性。结果GERD组治疗后血清GABA、BDNF、5-HT、NE、DA、MTL、GAS水平高于治疗前、但低于对照组,血清CCK水平及各量表评分均低于治疗前、但高于对照组(P<0.05);GERD组患者治疗后食管括约压力高于治疗前,立位返流时间比、卧位反流时间比、总反流时间均低于治疗前(P<0.05);30例疗效不良组GERD患者血清GABA、BDNF、5-HT、NE、DA、MTL、GAS水平及食管括约肌压力均低于70例疗效良好组,血清CCK水平、各量表评分、立位返流时间比、卧位反流时间比、总反流时间比均高于疗效良好组(P<0.05);GERD患者治疗前血清BDNF、5-HT、DA水平与MTL、GAS、食管括约肌压力呈正相关,与立位返流时间比、卧位反流时间比、总反流时间比、CCK呈负相关,GABA、NE与MTL、GAS、食管括约肌压力呈正相关,NE与立位返流时间比、CCK呈负相关性,GABA与立位返流时间比、总反流时间比、CCK呈负相关,差异有统计学意义(P<0.05)。结论GABA、BDNF、5-HT、NE及DA水平与胃内激素MTL、GAS、CCK的合成分泌及胃动力相关指标关系密切,这些神经递质可能参与GERD的发生和发展过程。

IL-6、NE-CPD联合皮肤温度变化对膝关节置换术后早期感染的预测价值

目的探讨持续性检测白细胞介素-6(IL-6)、中性粒细胞群落参数(NE-CPD)联合皮肤温度变化对膝关节置换术后早期感染的预测价值。方法选取2020年3月—2022年3月于河南省郑州市第六人民医院接受人工膝关节置换手术治疗的85例老年患者,根据术后3个月内是否发生膝关节假体感染分为感染组(n=7)与未感染组(n=78)。比较2组患者术前、术后1 d、术后7 d、术后1个月、术后3个月血清IL-6、血液NE-CPD及膝关节手术部位周围皮肤温度。结果2组患者术前及术后1 d血清IL-6水平比较,差异均无统计学意义(P>0.05);未感染组患者术后7 d、术后1个月、术后3个月血清IL-6水平低于感染组,差异均有统计学意义(P<0.05)。2组患者术前NE-CPD相关参数比较,差异均无统计学意义(P>0.05)。2组患者术后1 d的体积均值(MN-V-NE)均高于术前,术后7 d的MN-V-NE均低于术后1 d,术后1个月MN-V-NE均低于术后7 d,差异均有统计学意义(P<0.05);感染组患者术后3个月MN-V-NE高于术后1个月,差异有统计学意义(P<0.05);未感染组患者术后1 d、7 d、1个月、3个月MN-V-NE均低于感染组,差异均有统计学意义(P<0.05)。2组患者术前及术后不同时间点组间及组内传导性均值(MN-C-NE)比较,差异均无统计学意义(P>0.05)。感染组患者术后3个月中位角光散射均值(MN-MALS-NE)低于术前,差异有统计学意义(P<0.05);感染组患者术后1个月、3个月MN-MALS-NE低于未感染组,差异均有统计学意义(P<0.05)。感染组患者术后3个月高中位角光散射均值(MN-UMALS-NE)低于术前及未感染组,差异均有统计学意义(P<0.05)。感染组患者术后3个月低中位角光散射均值(MN-LMALS-NE)低于未感染组,差异有统计学意义(P<0.05)。感染组患者术后1个月、3个月轴向光吸收均值(MN-AL2-NE)低于未感染组,差异均有统计学意义(P<0.05)。2组患者术前及术后不同时间点手术部位周围皮肤温度比较,差异有统计学意义(P<0.05);感染组患者术后不同时间点手术部位周围皮肤温度均高于术前,差异均有统计学意义(P<0.05);未感染组患者术前及术后各时间点皮肤温度两两比较,差异均无统计学意义(P>0.05);未感染组患者术后不同时间点手术部位周围皮肤温度均低于感染组,差异均有统计学意义(P<0.05)。结论膝关节置换术后持续检测IL-6、NE-CPD及手术部位周围皮肤温度变化对术后感染的发生有较好预测价值,有助于预防术后感染,降低感染发生风险。

Geology, geochronology and geochemistry of large Duobaoshan Cu-Mo-Au orefield in NE China: Magma genesis and regional tectonic implications

Duobaoshan is the largest porphyry-related Cu-Mo-Au orefield in northeastern(NE)Asia,and hosts a number of large-medium porphyry Cu(PCDs),epithermal Au and Fe-Cu skarn deposits.Formation ages of these deposits,from the oldest(Ordovician)to youngest(Jurassic),have spanned across over 300 Ma.No similar orefields of such size and geological complexity are found in NE Asia,which reflects its metallogenic uniqueness in forming and preserving porphyry-related deposits.In this study,we explore the actual number and timing of magmatic/mineralization phases,their respective magma genesis,fertility,and regional tectonic connection,together with the preservation of PCDs.We present new data on the magmatic/mineralization ages(LA-ICP-MS zircon U-Pb,pyrite and molybdenite Re-Os dating),whole-rock geochemistry,and zircon trace element compositions on four representative deposits in the Duobaoshan orefield,i.e.,Duobaoshan PCD,Tongshan PCD,Sankuanggou Fe-Cu skarn,and Zhengguang epithermal Au deposits,and compiled published ones from these and other mineral occurrences in the orefield.In terms of geochronology,we have newly summarized seven magmatic phases in the orefield:(1)Middle-Late Cambrian(506-491 Ma),(2)Early and Middle Ordovician(485-471 Ma and~462 Ma),(3)Late Ordovician(450-447 Ma),(4)Early Carboniferous and Late-Carboniferous to Early Permian(351-345 and 323-291 Ma),(5)Middle-Late Triassic(244-223 Ma),(6)Early-Middle and Late Jurassic(178-168 Ma and~150 Ma),and(7)Early Cretaceous(~112 Ma).Three of these seven major magmatic phases were coeval with ore formation,including(1)Early Ordovician(485-473 Ma)porphyry-type Cu-Mo-(Au),(2)Early-Middle Triassic(246-229 Ma)porphyry-related epithermal Au-(Cu-Mo),and(3)Early Jurassic(177-173 Ma)Fe-Cu skarn mineralization.Some deposits in the orefield,notably Tongshan and Zhengguang,were likely formed by more than one mineralization events.In terms of geochemistry,ore-causative granitoids in the orefield exhibit adakite-like or adakite-normal arc transitional signatures,but those forming the porphyry-/epithermal-type Cu-Mo-Au mineralization are largely confined to the former.The varying but high Sr/Y,Sm/Yb and La/Yb ratios suggest that the ore-forming magmas were mainly crustal sourced and formed at different depths(clinopyroxene-/amphibole-/garnet-stability fields).The adakite-like suites may have formed by partial melting of the thickened lower crust at 35-40 km(for the Early Ordovician arc)and>40 km(for the Middle-Late Triassic arc)depths.The Early Jurassic Fe-Cu skarn orecausative granitoids show an adakitic-normal arc transitional geochemical affinity.These granitoids were likely formed by partial melting of the juvenile lower crust(35-40 km depth),and subsequently modified by assimilation and fractional crystallization(AFC)processes.In light of the geological,geochronological and geochemical information,we proposed the following tectonometallogenic model for the Duobaoshan orefield.The Ordovician Duobaoshan may have been in a continental arc setting during the subduction of the Paleo-Asian Ocean,and formed the porphyry-related deposits at Duobaoshan,Tongshan and Zhengguang.Subduction may have ceased in the latest Ordovician,and the regional tectonics passed into long subsidence and extension till the latest Carboniferous.This extensional tectonic regime and the Silurian terrestrial-shallow marine sedimentation had likely buried and preserved the Ordovician Duobaoshan magmatic-hydrothermal system.The south-dipping Mongol-Okhotsk Ocean subduction from north of the orefield had generated the Middle-Late Triassic continental arc magmatism and the associated Tongshan PCD and Zhengguang epithermal Au mineralization(which superimposed on the Ordovician PCD system).The Middle Jurassic closure of Mongol-Okhotsk Ocean in the northwestern Amuria block(Erguna terrane),and the accompanying Siberia-Amuria collision,may have placed the Paleo-Pacific subduction system in NE China(including the orefield)under compression,and formed the granodiorite-tonalite and Fe-Cu skarn deposits at Sankuanggou and Xiaoduobaoshan.From the Middle Jurassic,the consecutive accretion of Paleo-Pacific arc terranes(e.g.,Sikhote-Alin and Nadanhada)onto the NE Asian continental margin may have gradually distant the Duobaoshan orefield from the subduction front,and consequently arc-type magmatism and the related mineralization faded.The minor Late Jurassic and Cretaceous unmineralized magmatism in the orefield may have triggered mainly by the far-field extension led by the post-collisional(Siberia-Amuria)gravitational collapse and/or Paleo-Pacific backarc-basin opening.

Diagenetic and Mineralization Age of the Hehuaping Tin-polymetallic Orefield,Hunan Province

The Hehuaping tin deposit is a large deposit found in recent years during geological surveys. The discovered tin deposit includes not only rock-alteration type deposits in fault zones, but also deposits developed in interstratified rupture zones between Devonian carbonate rocks （Qiziqiao Formation） and sandstone （Tiaomajian Formation）. The finding of tin deposits of the latter type has greatly enriched tin-mineralization types in the famous Nanling polymetallic metallogenetic region and may provide us with a new potential orientation for prospecting of tin deposits in the region. It is commonly believed that the forming of the tin deposits in the Nanling region should be related to the Yanshanian instead of Indosinian granitic magmatism. Systematical zircon U-Pb SHRIMP dating in this paper shows that tin mineralizations have endured at least two stages. The early stage should be related to the intrusion of the main body of the Wangxianling granite, which was emplaced during the Indosinian period with a diagenetic and minerafized age of 224.0±1.9 Ma （MSWD=0.54）, and the late stage should be related to the intrusion of Yanshaulan granitic porphyry that took place after 142±3 Ma （MSWD=0.5）.

基于构造物理模拟的塔中北坡NE向走滑断裂形成机理

为了揭示塔中北坡NE向走滑断裂的形成机制,本文在前人研究的基础上,利用相似分析原理,设计了构造物理模拟实验平台,完成了3组构造物理模拟对比实验,模拟了塔中北坡NE向走滑断裂的形成演化过程,分析了塔中北坡NE向走滑断裂的形成机制。结果表明:塔中北坡NE向走滑断裂受控于先存的基底断裂以及上奥陶统厚层泥岩的调节作用,在周缘构造活动的作用下形成;塔中地区NE向走滑断裂经历了形成期和复活期两个阶段,先后受到SW方向与SE方向作用力挤压。

新型非对称惯容NES减震控制性能研究

为提高控制装置的减震性能及减小附加阻尼器的质量,基于非对称非线性能量阱(nonlinear energy sink,NES)提出一种附加惯容器的新型控制装置——非对称惯容NES。根据非对称惯容NES系统的工作原理推导出运动方程;在脉冲型荷载作用下进行控制参数数值优化,分析非对称惯容NES的能量鲁棒性和频率鲁棒性。分析地震作用下结构与控制装置响应,研究主体结构刚度变化前后的控制性能。应用数值小波变换对体系的地震响应时程进行功率谱分析,从能量的角度研究控制装置的减振机理。研究结果表明,非对称惯容NES具有极强的能量鲁棒性和频率鲁棒性,在地震作用过程中能有效减小顶层加速度峰值且所需行程更小,能在更广频域内与主体结构发生共振,因而其减震效率更高。非对称惯容NES减震控制性能与已有的非对称NES相当甚至更优,并能够减小40%阻尼器质量,在实际应用中具有更广阔的前景。

Genesis of the Xinqiao Gold-Sulfide Orefield, Anhui Province, China

The Xinqiao S-Fe-Cu-Au orefield is located in the Tongling ore cluster in the middle and lower reaches of the Yangtze River in East China. There have been many researches regarding the genesis of the Xinqiao orefield in recent years, showing that it belongs to various types, such as sedimentary-reformed type, stratabound-skarn type, sedimentary submarine rocks-hosted exhalative type. We propose that it was formed in two periods of mineralization base on systematic field observation and Pb and S isotopic analyses in nearly ten years. The first period was formed during a syngenetic sedimentary process, whereas the massive sulphide orebodies are mainly related to the Yanshanian granitic magmatism. Sulfide metallic mineral associations show zoning around a granite intrusion, i.e. magnetite and pyrite→pyrite, chalcopyrite and native gold→pyrite, sphalerite and galena. Gold orebodies occur outside the contact zone of the granite intrusion.

Rare-Earth Elements and Genesis of Lamprophyres in the Laowangzhai Gold Orefield, Yunnan Province

The Laowangzhai super-large gold orefield, which is situated in northern Mt. Ailaotectonic zone, Yunnan Province, is a typical gold orefield where lamprophyres are temporallyand spatially related to gold mineratization. Major element data show that lamprophyres in theorefield are of alkalic series and can be divided into potassic and K-rich calc-alkaline lamprophyres. The rocks are enriched in rare-earth elenlents as compared with the primary mantle andmid-ocean ridge basalts(MORB). Modelled calculations by the least squares method of Petrological Mixing show that the mantle source for the lamprophyres is enriched in rare-earth elements. The geotectonic development of western Yunnan, Sr and Nd isotopic compeitions, incompatible element patterns and linear programing calculations indicate that the fluids were de-rived from dehydration of submaine sediments which are enriched in ALK, LREE and incompatible elements and then were carried to mantle wedges as a result of plate subduction. That isthe main factor leading to the formation of a metasomatic fertile mantle in the area studied.

碱土金属原子与Ne原子间相互作用势的理论计算

本文基于无任何可调参数的势模型计算了碱土金属原子(Be、Mg、Ca、Sr、Ba)与Ne原子间相互作用势,得到的势能曲线及势阱位置和深度与现有的从头计算结果符合较好.本文的计算结果进一步验证了碱土金属原子与稀有气体原子间交换能主要来自碱土金属原子最外层s电子与稀有气体原子最外层p电子之间的交换作用.

激活后的NEG薄膜在氖气保护下的应用研究

NEG薄膜目前已成为新一代同步辐射光源储存环真空室表面处理的主要手段,HALF光源拟采用镀Ti-Zr-V NEG薄膜的方式以满足储存环真空度的设计要求。在一些情况下,需要打开真空室以更换某些故障件或安装插入件等,这将使NEG薄膜暴露大气,严重损伤薄膜的吸气性能及使用寿命,此外也需要数周时间使真空度恢复到原有水平。因此采取向真空室充入Ne气的方法能在一定程度上保护激活后的NEG薄膜,从而避免再次激活薄膜以延长使用寿命和节省时间,另外进行了充入N_(2)的对比实验。结果表明,充入Ne气后,真空度恢复后能满足静态真空度的要求,无需激活,从而延长NEG薄膜的使用寿命并且节省时间。而充入N_(2)后,真空度恢复后达不到静态真空度的要求。但通过低温激活,NEG薄膜均能恢复一定活性并达到静态真空度要求。相对于N_(2),在Ne气保护作用下真空度恢复的更好。通过对残余气体的分析,发现低温激活前后Ne的含量均极低,对束流的稳定性不会产生影响,进一步证明了充入Ne气的可行性。

Φ800 mm圆坯Q355NE凝固传热数值模拟和工艺实践

以钢厂断面尺寸为Φ800 mm圆坯Q355NE为研究对象,建立大圆坯传热模型,在不采用结晶器电磁搅拌的条件下,研究拉速和过热度对凝固过程的影响规律。结果表明:拉速对坯壳厚度、凝固终点位置和中心固相率的影响高于过热度,拉速每增加0.02 m·min^(-1),凝固终点后移2.6 m左右;过热度升高10℃,凝固终点后移0.21 m左右。实际生产中,二冷比水量0.18 L·kg^(-1)、过热度25℃、拉速0.14 m·min^(-1)时,出结晶器坯壳厚度超过43 mm,末端电磁搅拌充分发挥作用,铸坯中心疏松和中心缩孔较结晶器电磁搅拌(300 A/1.5 Hz)、二冷比水量0.18 L·kg^(-1)、过热度25℃、拉速0.16 m·min^(-1)工艺有所改善。