棒材穿水冷却过程温度场有限元分析

针对棒材穿水冷却过程,利用ANSYS有限元分析软件建立了棒材温度场预报模型,研究了棒材穿水冷却过程中的热边界条件,分析了棒材温度场的分布及其变化规律。该模型的计算结果与实测值吻合较好,能够准确地预测棒材穿水冷却后的温度分布和最终的组织。     

有限差分法在钢筋穿水冷却时温度场模拟中的应用

采用有限差分法对螺纹钢筋轧后穿水冷却时的传热行为进行了数值解析,对钢筋温度场控冷时的变化规律建立了数值模型,反算出了穿水冷却时的对流换热系数,得到了冷却过程中温度变化曲线,模拟结果符合现场实际情况.     

棒材穿水冷却温度场的仿真研究

针对棒材穿水冷却过程,采用有限元仿真软件ANSYS对其进行了温度场仿真,建立了棒材温度场预报模型。该模型的仿真结果与实测值相吻合,能够准确地预测棒材穿水冷却过程的温度分布,为棒材性能预报与优化控冷工艺提供依据。     

棒材穿水冷却温度场研究与工程应用

针对棒材穿水冷却过程,建立了棒材温度场数学模型。同时提出了对流换热系数公式并对其参数进行了优化,该温度场数学模型的仿真结果与实测值相吻合,能够准确地预测棒材穿水冷却过程的温度分布。采用棒材温度场数学模型可以计算轧钢车间水箱布置数量及恢复段的长度,为优化控冷工艺及轧钢车间工艺布置提供计算依据。     

低温钢筋穿水冷却工艺

 根据低温钢筋穿水冷却工艺特点,利用现场实测数据并结合理论分析得到不同规格低温钢筋穿水冷却过程中的对流换热系数。采用MSC Marc有限元软件与现场试制结果对低温钢筋穿水冷却过程进行了研究。研究了冷却水流量、终轧温度、穿水时间等工艺参数对低温钢筋温度场和组织演变的影响。模拟结果表明：当冷却水流量为120 m3/h时,钢筋芯部开始有珠光体转变;当冷却水流量为400 m3/h时,钢筋芯部无铁素体转变;冷却水流量为160～200 m3/h时,所获得的组织为针状铁素体与贝氏体。终轧温度增加50 ℃,出水冷装置后钢筋表面温度约增加10 ℃,返红温度约增加30 ℃;在200 m3/h水流量下冷却1.2 s,终轧温度为1 050 ℃时,其芯部组织为针状铁素体与细小的贝氏体。在相同水压与水流量条件下,随着穿水速度的增加,淬透层深度减小,返红温度增加。     

冷却器管道直径对大直径棒材冷却效果的影响规律

利用有限元耦合场数值模拟计算方法,对大直径棒材穿水冷却过程进行了三维非稳态数值模拟,分析了冷却器管道直径在棒材不同位置及对整体冷却效果的影响规律。模拟结果表明：在棒材整体方向上,管道直径D=220mm及D=240mm时冷却效果最好,D=350mm及D=400mm时冷却效果最差;在给定的工况条件下,棒材表层的温度在冷却过程中出现了波动,且冷却器管道直径越大波动现象越明显;棒材长度方向上温度分布不均匀。     

大直径GCr15轴承钢棒材穿水冷却规律及工艺研究

利用有限元耦合场数值模拟计算方法,对大直径棒材穿水冷却过程进行了三维数值模拟,在确定了冷却器结构的条件下,依据GCr15轴承钢的冷却工艺参数,研究冷却水流量和温度对棒材冷却效果的影响规律。模拟结果表明：冷却水流量对棒材温降效果影响较大,但当流量达到一定值时,继续增加流量,效果减弱;冷却水温对棒材温降效果影响较小。由此提出适合此种规格棒材的冷却水流量和水温区间。     

双机架紧凑式可逆炉卷轧机板材热连轧的温度场有限元研究

本文实现了对国内唯一一架双机架紧凑式可逆炉卷轧机板材热连轧的温度场有限元研究。采用弹塑性大变形热力耦合有限元法研究板材热连轧过程。利用有限元理论建立了板材热连轧模型,应用MSC／MARC软件进行计算,重点分析了轧制过程和变形区中轧件的温度场分布和变化。计算结果与实际生产情况相吻合,同时表明有限元理论可以实现对板材热连轧过程的数值模拟。     

双机架紧凑式可逆炉卷轧机板材热连轧的温度场有限元研究

实现了对国内唯一一架双机架紧凑式可逆炉卷轧机板材热连轧的温度场有限元研究。采用弹塑性大变形热力耦舍有限元法研究板材热连轧过程。利用有限元理论建立了板材热连轧模型，应用MSC／MARC软件进行计算，重点分析了轧制过程和变形区中轧件的温度场分布和变化。计算结果与实际生产情况相吻合，同时表明有限元理论可以实现对板材热连轧过程的数值模拟。     

推动模型在棒线材轧制过程模拟中的应用

基于三维热一机耦合有限元分析方法建立了刚性体推动模型，模拟棒线材多道次连轧过程。刚性体推动模型与常规有限元模型的比较结果说明刚性体推动模型可以在获得相同的精度前提下，显著地提高运算效率。将所建立的有限元模型应用于304不锈钢粗轧过程的数值模拟，得到了轧件6道次连轧过程的温度场、应变场和轧件的变形过程，并比较了各道次的轧制力模拟结果和轧机许用轧制力。温度场的模拟结果与测量结果的比较证明了模型的可靠性。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)