1500mm冷带切边圆盘剪的优化改造

针对山东钢铁莱钢集团公司板带厂1500mm冷轧拉矫圆盘剪切边质量差、生产效率低的问题,分别从设备程序控制、圆盘剪备件材质、工艺参数及操作模式、导料槽等方面对圆盘剪系统进行了优化改造,大大提高了拉矫圆盘剪的切边质量和圆盘剪的使用寿命。     

机械零件表面精整与光饰

机械零件表面精整与光饰加工技术适用范围非常之大,广泛用于机床机械、印刷机械、纺织机械、医疗器械、汽车、摩托车、电子电器、五金工具、仪器仪表、铸造、锻造焊接、冲压、压铸等各种不同材质的中小型异型零件的光整加工。研发生产出效率高、质量好、多工位控制、自动化程度高的新一代光整加工设备。光整机,可清除零件的机械加工毛刺,倒圆锐边与尖角。清除铸件、锻件和热处理件表面的残渣、杂质及氧化皮。在原基础上细化零件加工表面粗糙度1—2级。外观光亮．手感光滑柔和,外观具有精品效果。改善零件表面层应力状态,形成抗疲劳破坏的均匀压应力值（一般增加50％以上）。改善零件表面层金相组织状态,提高表面显微硬度（一般提高6％-20％）,形成耐磨损、抗疲劳的致密金属层（一般提高4倍以上）。提高零件清洁度,完成传动件的初期磨损．改善整机部分性能指标,缩短整机磨合期40％以上。机械零件表面精整与光饰加工技术将会普及到各行各业．产生巨大的经济效益和社会效益。     

变导程螺旋副滚子受力分析与优化设计

变导程螺旋副的滚子对螺旋副结构有较大影响。结合滚子修型线的相关理念对不同修型线分析,提出符合变导程螺旋副的滚子类型。以地铁门为研究对象,分析结构受力。为了更好的验证各滚子的优劣,利用ABAQUS对滚子进行接触受力分析。根据结果分析各种滚子在变导程螺旋副结构中的受力情况。经过分析后,选择适合变导程螺旋副的滚子曲线设计滚子。设计的滚子在ABAQUS中分析并与前面的进行比较,结果表明:设计的滚子所受应力较小,应力曲线平稳,符合结构要求。     

不同叶幕机械修剪方式下赤霞珠葡萄所酿酒的酚类物质研究

以赤霞珠葡萄为试材,研究机械修剪叶幕厚度对葡萄酒酚类物质的影响,为试验地葡萄管理提供理论基础。通过叶幕修剪机设置4种叶幕厚度（机械+人工、机械70 cm、85 cm、100 cm）,果实成熟后采收并采用传统工艺酿造干红葡萄酒,检测花色苷及非花色苷酚类物质组成及含量。结果表明,机械+人工及机械70 cm处理方式能够有效增加基本花色苷、乙酰化花色苷、香豆酰化花色苷及咖啡酰化花色苷含量,并丰富其组成;机械70 cm处理能促进黄酮醇及非类黄酮物质的积累,并增加其组成;而机械+人工处理降低了黄烷醇及羟基肉桂酸酚类物质含量。因此,在选择叶幕管理方式时,机械+人工及机械70 cm这两种处理具有现实的参考意义。     

分级修切及浮动废料刀结构设计

介绍了一种新型的分级修切及浮动废料刀结构,该结构彻底消除了传统废料刀引起的二次剪切问题,有效杜绝了毛刺及铁屑的产生,同时保证废料顺利滑落,极大地提高了模具使用寿命,改善了制件表面质量。     

数控齿条成形磨齿机中在线修整装置的研究

成形磨削的齿形精度主要取决于被修整砂轮的轮廓精度.研制了一种利用金刚石笔作为修整工具的成形砂轮在线修整装置,介绍了该成形砂轮修整装置的结构及工作方式,并设计了其控制系统.该控制系统用欧姆龙公司生产的小型PLC来完成,并通过PLC的高速计数器输入端子外接编码器和光栅尺的方式构成了一种简单的闭环结构,达到了提高砂轮修整精度的目的.     

面向飞机蒙皮柔性夹持数控切边的定位仿真系统及应用

针对切边过程中有效定位点动态变化的特征,提出＂X-2-1＂动态定位原理。基于几何约束关系实现了柔性工装对曲面零件的虚拟装夹,精确计算出柔性工装的调形参数。通过协调单元生死顺序和铣削力加载,实现了切边过程有限元仿真分析。选择典型飞机蒙皮零件进行了集成验证试验,试验分析结果表明加工精度满足制造要求。     

浪形保持架整形凹模加工工艺改进

浪形保持架整形凹模在等分车床上加工时,由于加工精度低,达不到使用要求,选择在镗铣加工中心加工,既减少了加工工序,又提高了模具的精度和寿命,提高了生产率。     

Bovine claw and limb disorders at claw trimming related to milk yield

As part of a cross-sectional study of Norwegian Red Cattle, associations of lameness, lesions at the tarsus, claw shapes, claw lesions, and claw trimming with milk yield were examined. Fifty-five tie-stall herds and 57 free-stall herds were sampled by computerized systematic selection, and 2,665 cows were trimmed and limb and claw disorders recorded. After exclusions, 2,599 cows were included in this study. Monthly recordings of milk were extracted from the Norwegian Dairy Herd Recording System. Most claw lesions were mild (score 1). The prevalence of moderate and severe lesions (score 2 and 3) did not exceed 5% for any of the lesions. Associations with test-day milk yield were identified using regression analyses (Proc Mixed) with repeated measurements within lactation and herd as random effect. Lactation curves were fit to visualize differences in changes in milk yield throughout the lactation. Milk yield was generally higher in cows with lesions at the tarsus, heel-horn erosions, and hemorrhages of the white line and the sole than in cows without these lesions, whereas cows with dermatitis yielded less than cows without dermatitis. Cows in lactation 1 with corkscrewed claws had reduced milk yield, whereas cows in lactations 2 and above had increased milk yield compared with cows without corkscrewed claws in respective lactations. Cows in lactation 1 yielded 0.47 ± 0.15 kg and cows in later lactations yielded 0.51 ± 0.15 kg more milk on test days after claw trimming than they did before when adjusted for days in milk. In this study, where most disorders were mild, the most evident results were higher milk yield in cows with lesions at the tarsus, heel-horn erosions, and hemorrhages of the white line and the sole than in cows without these lesions. Cows yielded more milk after claw trimming than they did before trimming.     

Production of fermentable media from vine‐trimming wastes and bioconversion into lactic acid by Lactobacillus pentosus

Trimmings of vineshoots, an agricultural waste with little use, were hydrolysed with dilute sulphuric acid (1–5%) in order to obtain sugar solutions suitable as fermentation media. The operational conditions for hydrolysis were selected on the basis of both the generation of hemicellulosic sugars (mainly xylose) and glucose and the concentrations of reaction byproducts affecting fermentation (furfural, hydroxymethylfurfural and acetic acid). Hemicellulosic hydrolysates were supplemented with nutrients and fermented with Lactobacillus pentosus, without any previous detoxification stage, to produce lactic acid. Under the best operational conditions assayed (3% H₂SO₄ and 15 min), 21.8 g lactic acid l^?1 was produced (Q_P = 0.844 g l^?1 h^?1, Y_P/S = 0.77 g g^?1), which represents a theoretical yield of 99.6%. Acetic acid was the primary byproduct formed from xylose, at about 25% of the lactic acid level. Copyright © 2004 Society of Chemical Industry