旋转连铸坯切分热模拟实验研究

采用φ300mm轧机，研究厚度为90mm坯料的切分道次及切入量，验证切分方案及切分楔形式的正确性，测定力能参数，结果表明：采用纯张力切分方案及选用的流线型切分楔是正确的，在该轧机上 坯料的切分宜用四道次。     

60／150kN耙式吊大车端梁裂纹处理

概述了60/150kN耙式吊大车端梁裂纹产生的原因和裂纹的处理方案，大车端梁头两侧腹板由12mm加厚到30mm，并增加主撑筋；贴板由14mm加厚到24mm。按此处理后，已使用22个月末出现裂纹。     

2400mm可逆铝带热轧机主传动方案选择

本文以2400mm可逆铝带热轧机主传动方案的制定为实例，从控制性能、动态响应、可靠性、节能效果、对电网污染程度及性能价格比几方面，详细分析了全数字直流传动系统、全数字交-交变频系统和基于IGCT的全数字交直交变频系统三个方案的优缺点，并结合有色金属加工企业的现状，论述了2400mm可逆铝带热轧机主传动方案制定过程。     

唐钢1650 mm可逆式冷轧机偏心补偿研究(续)

分析轧辊偏心对板带材厚度的影响，深入研究唐钢1650mm可逆式冷轧机的轧辊偏心补偿方案，由于通过数字程序直接实现，避免了传统偏心补偿方案的缺陷。     

唐钢1650mm可逆式冷轧机偏心补偿研究

分析轧辊偏心对板带材厚度的影响，深入研究唐钢1650mm可逆式冷轧机的轧辊偏心补偿方案，由于通过数字程序直接实现，避免了传统的偏心补偿方案的缺陷。     

变态箱型孔轧制大规格圆钢的生产实践

针对新钢特殊钢有限责任公司锻造厂生产Φ120mm，Φ130mm圆钢效率低、成本高问题，提出了以轧代锻的方案和变态箱型孔的设计方法，重点介绍了Φ650mm轧机轧制Φ120-130mm圆钢精轧孔型工艺参数的选择和确定，并把变态箱型孔应用于轧制实践，实现了以轧代锻，取得良好的效果。     

提高热叠扎薄板剪切精度的技术改造

本文分析了热叠轧薄板剪切时对角线差值大的设备影响因素，提出了简单易行的技术改造方案。使对角线差值由8－18mm减小到1－6mm，提高了剪切精度，满足了用户需求。     

大型轧钢箱形设备基础降水固结地基沉降分析和控制

结合某钢厂2250mm热轧工程大型箱形设备基础的地基处理，介绍了采用桩基方案与降水固结后天然地基方案两者的经济对比情况，并指出通过降水载荷试验、得到提高后的地基土承载力特征值及变形指标，经按有关规范中的公式计算沉降，结果满足变形要求，由此证明了方案的合理性。     

2800mm冷轧机换辊系统技术改造设计

阐述了改变2800mm冷轧机换辊方式的必要性，通过分析和理论计算论证了该方案的可行性，并进行方案设计和计算。     

首钢京唐公司2250mm热轧精轧机换辊装置移动轨道行程加长改造的设计与应用

针对首钢京唐公司2250mm热轧精轧机换辊装置移动轨道行程不能满足磨辊问天车同时起吊上下工作辊的问题，分析了原设计产生该问题的原因，通过对可能采取的修改方案进行技术和经济分析比较，得出了最优方案。     

立式板坯连铸机结晶器内液面波动的物理模拟

为优化200 mm×1 300 mm立式板坯连铸结晶器浸入式水口,采用1:1水模型模拟研究水口结构参数(侧孔断面-40 mm×80 mm,40 mm×40 mm和侧孔角度+15°和-15°)以及工艺参数(浸入深度-100～130 mm,拉速0.45～0.65 m/min)对液面波动的影响。结果表明:水口结构参数对液面波动的影响较明显;侧孔断面40 mm×40 mm,侧孔角度+15°的2^#水口的使用性能相对较好;浸入深度对液面波动量的影响不大;拉速对液面波动的影响与水口结构有关,对拉速变化的敏感程度由大到小的次序是2^#水口(40 mm×40 mm,+15°),4^#水口(40 mm×40mm,-15°),3^#水口(40 mm×80 mm,-15°),1^#水口(40 mm×80 mm,+15°)。     

轻压下参数对75Cr1高碳钢230 mm连铸板坯冶金质量的影响

基于有限元法,利用ANSYS软件模拟计算了高碳钢（0.73%~0.77%C）连铸板坯轻压下过程中热-机械塑性应变分布,分析了给定扇形段的压下量2 mm+2 mm,3 mm+3 mm和2 mm+2 mm+2 mm对压下区间和位置的塑性应变的影响,并通过现场试验对模拟结果进行了验证。结果表明,塑性应变模型模拟值与实测值吻合;热变形过程中,铸坯心部的等效应变最大,表面节点次之,1/4位置等效应变最小;热-机械塑性应变随着压下量和压下速率的增加而增加,3 mm+3 mm压下模式具有较好的压下效果。生产试验结果表明,采用2个扇形段（6^#和7^#或7^#和8^#）进行2.2 mm+2.3 mm轻压下铸坯较优化前3个扇形段（6^#,7^#和8^#）1.5 mm+1.5 mm+1.5 mm轻压下铸坯中心偏析2.0级和中心疏松2.0级提高中心偏析0.5级和中心疏松0.5级,显著改善了连铸板坯的低倍质量。     

火花放电原子发射光谱分析中不同规格线材类型标准化样品兼容性探讨

在实际生产应用中,火花放电原子发射光谱法广泛应用于线材的日常检验。而线材的规格种类繁多,若每个牌号每种规格都进行类型标准化不仅影响分析效率,而且会提高分析成本。实验针对小规格线材,分别使用ϕ6.60 mm、ϕ5.42 mm、ϕ4.22 mm、ϕ3.02 mm 共4种类型标准化样品(以下简称类标)分析14种不同规格的待测线材,按照标准要求进行精密度和正确度的验证,开展了将火花放电原子发射光谱法类标按直径进行归并的可行性研究。结果表明,ϕ6.60 mm的类标可以满足ϕ5.82 mm～ϕ7.40 mm样品的准确分析;ϕ5.42 mm的类标可以满足ϕ5.02 mm～ϕ5.82 mm样品的准确分析;ϕ4.22 mm的类标可以满足ϕ4.22 mm～ϕ4.60 mm样品的准确分析;ϕ4.22 mm以下的线材只能进行相应规格的类型标准化。     

Differential susceptibility to neurofibrillary pathology among patients with Down syndrome

Individual differences in the development of neurofibrillary changes were examined in eight cortical regions in the brains of 43 subjects with Down syndrome (DS; age range, 15-69 years) using sections stained with monoclonal antibodies (mAb) tau-1 and 3-39. Neurofibrillary pathology was found in 4 cases below 36 years of age and in all 20 cases above that age. In the 24 positive cases, numerical density of pretangles stained with tau-1 and 3-39, respectively, was 6.1/mm2 and 0/mm2; early tangles, 5.0/mm2 and 5.3/mm2; mature tangles, 4.0/mm2 and 5.0/mm2 (p < 0.01); and end-stage tangles, 0.04/mm2 and 2.5/mm2 (p < 0.001). Numerical density of pretangles stained with mAb tau-1 and tangles and plaques stained with mAb 3-39 correlates weakly with age (r = 0.43; p< 0.02), and together with the wide range of numerical densities suggested heterogeneity of the population examined. Cluster analysis based on two variables - i.e., numerical density of pretangles stained with mAb tau-1 and neurofibrillary tangles (NFTs) and plaques stained with mAB 3-39, distinguished three groups of subjects with severe, moderate and weak changes. The severely affected group of 5 subject (21%) had an average 54.6/mm2 of neurons and 13.9/mm/ plaques with neurofibrillary changes, whereas the moderately affected group (6 subjects; 25%) showed a significantly lower numerical density of neurons and plaques with neurofibrillary changes (25.7/mm2 and 8.1/mm2, respectively) as compared with the most affected group. Most of the subjects (13; 54%) belong to the third group with only 2.2/mm2 of neurons and 1.4/mm2 plaques with neurofibrillary pathology. Comparison of these three groups of Down syndrome subjects representing high, moderate, and low susceptibility to neurofibrillary changes with the general population suggests that the risk of Alzheimer disease is similar but the onset of pathological changes is earlier in DS.     

国内外高牌号无取向硅钢夹杂物的控制效果与评价

采用非水溶液电解提取、扫描电镜和X光微区分析方法,考察了国内、外部分钢企代表性钢种成品试样中磁性能相当、高牌号无取向硅产品中夹杂物类型和数量。结果表明,四个企业A、B、C、D其成品磁性能水平相当,而其中的夹杂物控制在类型、数量上存在明显的差异。其中,A 企业的夹杂物以 CaO 夹杂为主;B、C、D 企业的夹杂物以 MnS、AlN为主。A、B、C、D 四个企业,1.0 μm 以下的夹杂物数量分别为 31万个/mm³、1 200万个/mm³、1 800万个/mm³和85万个/mm³;1.0 μm～10 μm之间的夹杂物数量分别为 108.4万个/mm³、34.5万个/mm³、71.6万个/mm³和5.6万个/mm³;10 μm 以上夹杂物数量四个企业均很少。     

水口吹氩工艺参数对180mm×700mm板坯结晶器宽面含气率分布的影响

通过建立的6:10几何相似比的模拟180mm×700 mm板坯结晶器的水模型（108 mm×420mm）,使用数字图像处理技术,分析了水量2.54~3.16 m³/h,气量0.037~0.110 m³/h,滑板开口度51%~100%,水口浸入深度78~108 mm等参数对水口吹氩板坯结晶器水模型内宽面含气率分布的影响。结果表明,当水量3.16 m³/h（相当于原型1.50m³/h）,气量0.037 m³/h（原型0.120 m³/h）,水口底部形状为凹形,滑板开口度51%,水口浸入深度78 mm（原型130 mm）时,水模型内气泡分布相对均匀,有利于流场的改善和夹杂的上浮去除。180 mm×700mm铸坯的生产性试验表明,采用优化的参数生产的超低碳钢连铸坯中≥30μm的夹杂物量和夹杂物总量均显著降低。     

Effects of heart rate on vulnerability to fibrillation in a computer model

The SET-2400W is a newly designed whole-body PET scanner with a large axial field of view (20 cm). Its physical performance was investigated and evaluated. The scanner consists of four rings of 112 BGO detector units (22.8 mm in-plane x 50 mm axial x 30 mm depth). Each detector unit has a 6 (in-plane) x 8 (axial) matrix of BGO crystals coupled to two dual photomultiplier tubes. They are arranged in 32 rings giving 63 two-dimensional image planes. Sensitivity for a 20-cm cylindrical phantom was 6.1 kcps/kBq/ml (224 kcps/microCi/ml) in the 2D clinical mode, and to 48.6 kcps/kBq/ml (1.8 Mcps/microCi/ml) in the 3D mode after scatter correction. In-plane spatial resolution was 3.9 mm FWHM at the center of the field-of-view, and 4.4 mm FWHM tangentially, and 5.4 mm FWHM radially at 100 mm from the center. Average axial resolution was 4.5 mm FWHM at the center and 5.8 mm FWHM at a radial position 100 mm from the center. Average scatter fraction was 8% for the 2D mode and 40% for the 3D mode. The maximum count rate was 230 kcps in the 2D mode and 350 kcps in the 3D mode. Clinical images demonstrate the utility of an enlarged axial field-of-view scanner in brain study and whole-body PET imaging.     

连铸坯中心偏析对LX72A钢帘线合股断丝的影响

70 t BOF-LF-Φ380 mm CC-开坯成150 mm×150 mm方坯-CR和200 t BOF-LF-200 mm×200mm CC-CR两种工艺路线所生产的Φ5.5 mm盘条经拉拔成Φ0.22 mm钢帘线合股过程的断丝率为Φ380mm圆铸坯工艺-2.86次/t,200 mm×200 mm方坯工艺-<1次/t。检验结果表明,圆坯工艺生产的盘条严重的中心偏析是大量断丝的主要因素,150mm×150 mm轧坯的宏观碳偏析高达1.11。采用断面尺寸200 mm×200 mm以上的方坯连铸工艺流程,中间包钢水过热度15～25℃,拉速恒定,采用结晶器和末端电磁搅拌,可有效地减轻中心偏析。     

A comparative evaluation of halo pin designs in an immature skull model

To design an improved halo pin for use in pediatric patients, three commonly used halo pins were evaluated with a mechanical testing apparatus and segments of prepared fetal calf skull. The pins were driven through the bone segments while the load at the bone-pin interface was measured. New pins were designed with respect to pin tip and flange width and similarly compared. Mean maximum loads to penetration, normalized for bone segment thickness, were 55.6 N/mm for the PMT Corporation pin, 61.5 N/mm for the Bremer pin, and 73.6 N/mm for the Ace pin. Four new, short tipped pins were designed and compared with the Ace pin, and there was no significant difference. Finally, four new pins were designed with varying flange widths. Mean maximum loads, normalized for bone segment thickness, were 68.9 N/mm for the 4.2 mm flange, 72.2 N/mm for the 4.7 mm flange, 92.9 N/mm for the 5.2 mm flange, and 96.4 N/mm for the 5.7 mm flange. The findings of this investigation are clinically important because they may help to explain the variability in the complication rates seen with the use of different halo systems in children. The three halo pins currently on the market have different pin designs, including tip lengths and flange distances, which contribute to the difference in load to penetration for each pin. The new, wide flanged, short tipped halo pin design might decrease the complication rate of halo use in children by providing an improved capacity to resist penetration despite increased loads of application.     

复吹转炉钢-渣间容量传质系数的水-油模型

在熔池直径880mm、深258mm的冷态模型中，利用水模拟钢水、机油模拟渣、苯甲酸模拟钢-渣间传输物质来研究熔池直径5285mm、深1545mm的复吹转炉吹炼工艺参数对钢-渣间容量传质系数的影响。结果表明，枪位350mm，顶吹流量117m^3/h，底吹流量1．68m^3/h至2．36m^3/h时，传输物质苯甲酸的容量传质系数变化最显著，在采用枪位350mm，顶吹流量140m^3/h，底吹流量1．68m^3/h，底枪布置方式为8孔对称布置在0．66直径的圆上时，传输物质的容量传质系数最大。