基于现场的热连轧温度控制关键技术

为了目标轧件拥有优良的内部组织结构,获得好的强韧性能,采用对带钢热连轧温度制度进行在线控制。引入自学习功能,通过对热对流散热系数进行修正和层流冷却段温度累积求和,机理模型更适用于生产实际。     

动态修正轧机弹跳值提高热轧带钢头尾厚度精度

为了得到高精度的辊缝设定值,分析了某钢铁公司热连轧厂轧机弹性方程,找出更接近实际的轧机弹性曲线,以便在假定带钢塑性系数为常数的条件下,在线动态给出带钢穿带过程中轧机弹跳值修正量。结果表明：一段轧机弹跳回归模型精度比二段轧机弹跳回归模型高一个数量级。通过动态修正轧机弹跳方程,消除了辊缝设定模型中的刚度补偿系数误差,可以提高热轧带钢头尾部厚度精度。     

Magmasoft模拟条件与低压铸造铝车轮生产条件匹配性研究

分析了Magmasoft软件边界条件数据库与低压铸造铝车轮实际生产条件存在的差别,对模拟分析时使用的边界条件进行了修正,对换热系数进行了模拟计算,对实际生产工艺中模具的冷却系统进行了改进,验证了修正后的软件边界条件设置与改进后的模具冷却系统的实际匹配性。在修正后的软件边界条件及模具冷却的基础上,采用Magmasoft软件,使用实际生产工艺进行模拟分析,并对温度场进行了理论与实际的校验。     

连铸坯坯壳厚度的射钉测试及凝固系数的修正

针对目前采用射钉测量铸坯坯壳厚度的方法中没有考虑钉子射入铸坯后熔化时间的问题,建立了钉子在铸坯内部的传热数学模型,同时应用有限元软件MSC.Marc对钉子熔化过程进行数值模拟,提出了凝固系数的修正方法和计算式,以实际算例说明了凝固系数、凝固终点位置在修正前后分别有0.5%和1.2%的偏差,采用修正以后的计算式,凝固系数和凝固终点的计算更为准确,对实际生产具有指导意义.     

K因子在ZAF迭代计算中的作用和强基体效应样品中ZAF修正系数的具体分析

ZAF法是目前电子探针(EPMA)定量分析时最常用的修正方法,其本质就是准确测量样品中每个元素的K因子,然后进行K因子的数学迭代计算(数学修正)。理解了这一修正过程,有利于操作者正确、精确地设置定量分析实验条件。对于超轻元素含量不低或基体效应强的样品,K因子和实际浓度相差较大,修正系数相应也较大,这种情形下K因子的准确测量尤为重要。本文首先对ZAF法的迭代计算数学过程进行了推导,说明K因子是ZAF定量分析的核心;通过CrTiAlC磁控溅射材料(C质量分数约为8%)的微区定量分析结果,进一步分析造成C、Al元素的K因子和实际浓度相差较大的物理原因并对ZAF修正系数的每一项进行分析,进一步理解ZAF定量的数学迭代过程,建立强基体效应样品系统下的定量分析参数设置思路。     

中厚板轧制过程基于灰色关联度的厚度修正方法

由于中厚板轧制过程传统道次修正方法稳定性较差,提出了基于灰色关联度的道次修正算法.通过灰色关联度模型计算出最近生产的n块钢板所有道次以及当前正在轧制钢板前m道次与当前轧制道次轧制力自学习系数的关联度,根据关联度的高低来确定当前道次和后续道次的自学习系数,并通过道次修正对后续辊缝进行二次调整,以获取精确的目标出口厚度.实际应用结果表明,产品目标出口厚度的命中率提高了2.5%～3.0%,具有很高的现场应用价值.     

毛细管升高法测水的表面张力系数及其修正

对用毛细管升高法测水的表面张力系数的测量方法进行了修正,给出了修正后的测量公式,并以粗细不同的毛细管为实验举例,验证了修正后的测量公式的优越性,消除了实验教学中的疑点.     

宝钢2030mm热镀锌机组退火炉F1段燃烧状况仿真

为了研究宝钢2 030 mm热镀锌机组退火炉内F1段的燃烧状况以及不同煤气过剩系数设定值对该段燃烧状况的影响,利用FLUENT软件,通过仿真手段再现了F1段的燃烧情况,包括炉内温度分布、气体组分等;并通过对不同煤气过剩系数下的燃烧仿真结果进行了比较,确定了最佳煤气过剩系数设定值。通过对不同燃烧氛围(氧化性氛围与还原性氛围)下炉内燃烧情况的仿真结果分析,从理论上证实了氧化性氛围下进行退火的不可行性,为实际生产提供了一定指导作用。     

中厚板轧制过程基于灰色关联度的厚度修正修正方法

 基于中厚板的轧制特点,提出了基于灰色关联度的道次修正算法。通过灰色关联度模型计算出最近生产的n块钢板所有道次以及当前正在轧制钢板前m道次与当前轧制道次轧制力自学习系数的关联度,根据关联度的高低来确定当前道次和后续道次的自学习系数,并通过道次修正对后续辊缝进行二次调整,以获取精确的目标出口厚度。实际应用结果表明,产品的目标出口厚度的命中率有了大幅度的提高,具有很高的现场应用价值。     

铁合金电炉设计中几个问题的讨论

本文分析比较了铁合金设计中电炉生产率的几个常规计算公式;提出了综合修正系数的概念及其作用,并根据实际生产数据确定出其取值范围;指出了电炉容量和变压器选型等应注意的几个问题。     

Case Study: River Training and Its Effects on Fluvial Processes in the Lower Yellow River, China

More than 50?years’ river training practices in the Lower Yellow River provide valuable experience in river management for flood control in rivers having rapid flow changes, silting beds, and active channel migrations and are of importance in understanding the fluvial processes in regulated rivers with high sediment loads. Planned channel alignments for river training in the Lower Yellow River usually consist of a series of consecutive moderate bends representing the natural tendency of flows. Flow guide works, namely spur dikes, were constructed on the concave banks of the planned bends to protect the channel against scouring and migration by deflecting the current away from bends and further guiding the main flow from one bend to the next one. As a result, well-planned flow guide works can play a crucial role in limiting channel shifting and migration and in establishing a relatively stable channel. Enough flow guide works, on both sides together reaching about 80% of the channel length, may change the transitional and braided channel patterns to a confined meandering pattern.     

兰州安宁区滨河北路西段工程地质特性及地基基础建议

兰州市位于甘肃省中部,属中温带干旱和半干旱气候区,干燥少雨,四季分明,昼夜温差很大。研究地段位于黄河上游的兰州安宁区滨河北路西段黄河北岸Ⅰ级阶地,在黄河安宁区段具有代表性。本文通过作者多年在该区不同地段积累的工程地质勘察实际资料,结合地貌和沉积特征,从地层空间分布、物理力学性质等方面系统分析评价了岩土工程地质特性,选择了区内建筑持力层、提出了地基基础类型方案和建议,为该地段开发和建筑设计提供参考。     

Rare earth element content in the SPM of Daliao river system and its comparison with that in the sediments, loess and soils in China

Content and distribution patterns of rare earth dements （REEs） in the suspended particulate material （SPM） of Daliao River system were investigated and compared with those in the fiver and sea sediments, loess, and soils of China. Twenty-seven samples of SPM were taken in Daliao River system and digested with various acids followed by ICP-MS analysis for REEs and ICP-OES analysis for Al, Fe, Mn, Ti, Mg, Ca, Na, and K, to measure the total concentrations of these elements. Results indicated that the spatial change in the content of REEs was great, with the coefficient of variance （CV） from 84% to 105%, while the contents of REEs were significantly correlated with each other. Chondrite-normalized patterns of REEs were characterized by higher enrichment of light REEs than heavy REEs, and a depletion of Eu in the SPM was generally found. The positive anomaly of Eu in the SPM of Xi River was due to anthropogenic source in Shenyang City. Furthermore, chondfite- and upper continent crust-normalized patterns of REEs in the SPM of Daliao River system, sediments of Yangtze River and Yellow River, sediments of Yellow Sea, East Sea, South Sea of China, and loess and soil of China, were very similar to one another. These demonstrated that the weathering and sedimentary processes resulted in constant REE distribution not only in the typical sedimentary rocks, but also in the modem riverine particle, sea sediments, loess, and soils.     

Tracer Study of Mixing and Transport in the Upper Hudson River with Multiple Dams

In October 2001, ～ 0.2?mol of SF6 was injected into the upper Hudson River, a modified natural channel with multiple dams, at Ft. Edward, N.Y. The tracer was monitored for 7 days as it moved ～ 50?km downriver. The longitudinal evolution of the tracer distribution was used to estimate one-dimensional advection (9.0±0.2?km?d?1) and dispersion (17.3±4.0?m2?s?1) along the river axis. Comparison of these results to tracer studies on channels without dams suggests that dams reduce longitudinal dispersion below the value expected in a natural channel with the same discharge. SF6 loss through air–water gas exchange along the river and at two dams (10.7?m combined height) was estimated by observing decay in peak concentration. Losses at dams (approximately 50% per dam) were dominant. The estimated gas exchange at dams was compared to a simple model adapted from those available in literature. Small amounts of tracer were trapped in a canal segment ( ～ 5?km long) that parallels the river, where advection and dispersion were sharply reduced.     

Predicting the Morphodynamic Response of Silt-Laden Rivers to Water and Sediment Release from Reservoirs: Lower Yellow River, China

The high sediment load of the Yellow River results in rapid infilling of its reservoirs when sediment is not regularly flushed. Simultaneously, the downstream reaches of the Yellow River experience extremely high siltation rates, which are reduced when sediment is retained in its reservoirs. To minimize siltation in the reservoirs and the downstream river bed, water and sediment are released from the reservoir in a controlled way through flushing experiments. In this paper, we analyze the effect of such a flushing event on the downstream river bed through data analysis and numerical modeling. Sedimentation may be minimized by relating the amount of sediment released from the reservoir to the sediment available for release through operational monitoring and by releasing relatively clear water after turbid water. Despite this flushing of sediment, the reservoir will eventually fill up, and more sediment released again into the lower Yellow River. The change in discharge magnitude and frequency brought about by the reservoir will then probably result in increased siltation rates in the lower Yellow River compared to the predam situation.     

Wash Load and Bed-Material Load Transport in the Yellow River

It has been the conventional assumption that wash load is supply limited and is only indirectly related to the hydraulics of a river. Hydraulic engineers also assumed that bed-material load concentration is independent of wash load concentration. This paper provides a detailed analysis of the Yellow River sediment transport data to determine whether the above assumptions are true and whether wash load concentration can be computed from the original unit stream power formula and the modified unit stream power formula for sediment-laden flows. A systematic and thorough analysis of 1,160 sets of data collected from 9 gauging stations along the Middle and Lower Yellow River confirmed that the method suggested by the conjunctive use of the two formulas can be used to compute wash load, bed-material load, and total load in the Yellow River with accuracy.     

黄河水源污染对画匠营子水厂供水的影响

黄河是包头市的主要水源.本文分析了由于黄河过境流量减少及河水污染对画匠营子自来水总厂造成的影响,并对此提出了改进建议.     

Channel Degradation Downstream from the Three Gorges Project and Its Impacts on Flood Level

The effects of the sediment regime on the flood level in the middle reach of the Yangtze River before and after the construction of the Three Gorges Dam (TGD) are investigated. Before the dam construction, the sediment regime has driven the flood level higher and higher over recent decades in the middle reach of the Yangtze River, which has reflected changes in the location and amount of sediment deposition. After dam completion, the magnitude and rate of channel degradation determines the process of flood stage lowering but they are difficult to estimate owing to insufficient understanding of the sediment discharge recovery process. To make a rational prediction of channel degradation of the Yangtze River downstream from the TGD, the sediment transport rate during channel degradation downstream from other dams is examined. It is found that, for any grain size, postdam sediment transport rates cannot exceed the predam level at any location along the downstream channel. Erosion amounts predicted for the reach downstream from the TGD before its closure are too high. In light of this, a numerical simulation of the channel degradation process is carried out. The results indicate that, although degradation takes place immediately after the TGD closure, the flood level in the middle reach of the Yangtze River will still remain at its predam condition in the following 20 years. This is determined not only by the regional characteristics of the middle reach of the Yangtze River but also by the common law of sediment transportation downstream from dams.     

Sediment provenance discrimination in northern Okinawa Trough during the last 24 ka and paleoenvironmental implication:rare earth elements evidence

Rare earth elements(REE) compositions and discriminant function were successfully used to examine high resolution sediment source changes in the northern Okinawa Trough over the last 24.1 ka,especially for the influence from the Yellow River and the Tsushima Warm Current(TWC) that has not been well solved.Variations of these parameters were clearly divided into three distinct depositional units.During Interval 1(24.1-16.0 ka BP),the paleo-Yellow River and the paleo-Yangtze River mouths were situated near the studied area and could have played major roles in the sedimentation therein.In Interval 2(16.0-7.3 ka BP),these river mouths gradually retreated with global sea-level rise,leading to less fluvial inputs from them to the northern Okinawa Trough.Meanwhile,formation of the TWC could carry some sediment loads of Taiwan to the studied core,especially during its late phase(8.0-7.3 ka BP).Modern oceanographic conditions,with a predominance of the TWC,were finally established since the beginning of Interval 3,causing more terrigenous contribution from Taiwan to the studied area.Sub-sequently,modern depositional environments mainly influenced by the Yellow River,the Yangtze River,and the TWC were finally formed.     

磁性活性炭的制备及去除河涌水中COD的研究

采用改性磁种——磁性活性炭复合吸附材料结合磁分离法处理河涌水,考察了絮凝剂种类及用量、改性磁种投加量、作用时间、磁场强度等对河涌水中COD的去除效果。结果表明,采用改性磁种——磁性活性炭吸附并结合高梯度磁分离处理河涌水COD效果明显,在聚合氯化铝(PAC)用量10g/L、改性磁种用量30g/L、改性磁种作用时间20min、分离磁场强度8 000kA/m的条件下,原水含COD 90.18mg/L,出水含COD可降至6.59mg/L,除COD率达92.69%,达到《地表水环境质量标准》(GB 3838—2002)中的Ⅰ类水COD标准。