致密砂岩气聚集模型与定量模拟探讨

将致密砂岩气聚集带划分为连续带和过渡带,并建立相应的地质模型。连续带位于构造低部位或斜坡处,砂岩直接覆盖在烃源岩之上,具有天然气大面积连续分布,上部不受盖层控制,下部无明显底水等特点;过渡带紧邻连续带,位于斜坡的上倾方向或构造较高部位,砂岩与烃源岩没有直接接触,天然气主要分布在储层物性相对较好的“甜点”中,天然气藏具有常规气和连续气2种特点。连续带以纳米级孔喉结构为特征,天然气运聚主要驱动力为生气产生的超压;过渡带以微米级孔喉结构为特征,天然气运聚主要驱动力为浮力。基于上述认识,建立“排挤式”和“置换式”致密砂岩气聚集数值模型。该模型在四川盆地合川地区的应用效果符合率达到90%,指出还有一半的天然气资源未被发现,主要分布在合川地区东北部、潼南地区北部和潼南地区东南部。     

Effect of Pre-deformation on Grain Ultrafining by Intercritical Deformation in Low-Carbon Microalloyed Steels

In this study, the effect of pre-deformation at recrystallization and non-recrystallization zone on the grain ultrafining by the subsequent intercritical deformation(ID) was investigated on low-carbon microalloyed steel. The results showed that ultrafine grain microstructure with an average size of ~1.0 lm was fabricated through pre-deformation in the recrystallization zone followed by ID. When pre-deformed at the non-recrystallization zone prior to ID, the grain size increased to 1.6 lm with a heterogeneous distribution along with the well-developed dynamic recovery of ferrite. The grain ultrafining mechanism was attributed to the combined action of the deformation-induced ferrite transformation and the continuous dynamic recrystallization. In particular, the continuous dynamic recrystallization process during ID occurred on the pro-eutectoid ferrite as a result of the subgrain rotation mechanism and the absorbing dislocations mechanism.     

High-order approximations of three-phase-lag heat conduction model: Some qualitative results

This article deals with some high-order approximations of the three-phase-lag heat transfer model aiming, at first, to identify the restrictions that make them well-posed consistence. Consequently, a first result about the uniqueness and continuous dependence of the solutions with respect to the given initial data and to the supply term is established for the related initial boundary value problems. Subsequently, to provide a more comprehensive analysis of the model, some further spatial decay results are established, this time conveniently relaxing the hypotheses about the delay times and the thermal conductivities. More precisely, a theorem of influence domain is proved for the wave propagating models and an exponential decaying estimate of Saint-Venant type is established for the diffusive models.     

Q345B连铸坯表面夹渣缺陷的形成原因及控制

描述了Q345B铸坯表面夹渣缺陷的宏观形貌,并通过扫描电镜及能谱仪对缺陷形貌进行观察和能谱分析。结果表明,缺陷内主要为氧化铁皮并含有保护渣成分。分析了铸坯表面夹渣缺陷的形成原因主要有以下4个方面:浸入式水口设计不合理引起的结晶器液面波动卷渣、结晶器内弯月面受冲击夹渣、保护渣成分不均匀引起的分熔现象及结晶器振动负滑脱时间长导致的下渣不均匀。并提出优化措施:1)优化浸入式水口的结构,将侧孔角度为25°减小至18°;2)改善结晶器流场,板间的氩气流量由原来的5 L/min减少至3 L/min以下,SEN的插入深度控制在90~130 mm;3)优化保护渣成分和性能,将保护渣熔点由原来的1 050℃提高至1 150℃,碱度大于1,黏度0.12~0.2 Pa·s,降低了保护渣的消耗;4)调整结晶器振动参数,使负滑脱时间由原来的0.207 s减至0.165 s。22炉的现场试验结果表明,优化后的工艺由于铸坯缺陷引起的中厚板表面裂纹发生率控制在1%以下,并实现了铸坯、中厚板表面质量的稳定控制。     

连退工艺对烘烤硬化钢CR180B2力学性能的影响

通过连续退火模拟试验,研究了连退工艺参数对烘烤硬化钢CR180B2力学性能的影响,进而对连退工艺进行了优化。结果表明：随着退火温度的提高,试验钢的强度下降,伸长率、n值、r-以及BH值有所提高;随着缓冷温度的提高,试验钢的强度下降,伸长率和r-增加,n值几乎没有变化,而BH值显著增加;随着快冷冷速的增加,试验钢BH值逐渐增加。     

高强钢连铸板坯中心偏析的分析及改善措施

分析了评价连铸坯中心偏析的几种方法及其各自优缺点,并综合比较了各类中心偏析的形成机制和控制技术的特点。在实际生产过程中对于钢水成分、钢水纯净度、钢水过热度、连铸冷却工艺、板坯缓冷、连铸机辊缝控制、轻压下的参数选择等关键控制技术进行了讨论。     

宽板连铸结晶器设计若干技术问题分析

结合国内涟源钢铁公司和伊朗穆巴拉克宽板连铸结晶器设计技术特点和工艺要求,详细提出宽板结晶器主要部件在设计过程需要优化和改进的要点,为后来宽板连铸项目的结晶器设计、优化提供更好的基础和思路。     

不锈钢板坯内外弧尺寸差异分析及解决措施

结合304奥氏体不锈钢高温凝固特性及现场连铸浇铸参数,分析304不锈钢连铸铸坯内外弧宽度尺寸相差约为4～7 mm的具体原因,如结晶器内外弧冷却不同、内外弧铜板锥度不同、水口不对中等。详细研究因结晶器内外弧冷却不同对铸坯内外尺寸的影响,实践证明,调整结晶器内外弧水量可以有效改善内外弧铸坯尺寸差异问题。     

宝钢炼钢异常板坯的分析与控制

针对宝钢炼钢过程中的板坯异常问题,进行了现场跟踪与分析,得出炼钢过程中板坯异常主要与过热度和液面波动异常有关。研究发现,炼钢各工序间时间间隔不适宜,易造成工序间温度符合率低下;头尾坯、异钢种交接坯生产中拉速不稳定以及正常板坯浇铸过程中氩气流量过大,均易造成液面波动异常,从而导致板坯异常。通过制定相应火车时刻表、改进炼钢生产计划编排、优化连铸氩气流量等措施,有效控制了浇铸过程中过热度异常与浇铸液面波动问题,使宝钢异常板坯量得到有效的改善。     

Effect of substrate concentration on fermentative hydrogen production from sweet sorghum extract

The aim of the present study was to assess the influence of substrate concentration on the fermentative hydrogen production from sweet sorghum extract, in a continuous stirred tank bioreactor. The reactor was operated at a Hydraulic Retention Time (HRT) of 12 h and carbohydrate concentrations ranging from 9.89 to 20.99 g/L, in glucose equivalents. The maximum hydrogen production rate and yield were obtained at the concentration of 17.50 g carbohydrates/L and were 2.93 ± 0.09 L H₂/L reactor/d and 0.74 ± 0.02 mol H₂/mol glucose consumed, corresponding to 8.81 ± 0.02 L H₂/kg sweet sorghum, respectively. The main metabolic product at all steady states was butyric acid, while ethanol production was high at high substrate concentrations. The experiments showed that hydrogen productivity depends significantly on the initial carbohydrate concentration, which also influences the distribution of the metabolic products.