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1.
从可持续发展和经济建设两方面分析了我国长型材生产面临的问题,认识到发展先进长型材的必要性。指出,先进长型材的轧制应当实现4个主要功能,即:形变温、速度组织演变的最佳耦合、尺寸精度与产品最终组织目标的统一、高表面质量和高外形质量。这些功能反映了长型材轧制技术和钢材一体化生产的发展趋势。  相似文献   

2.
介绍了八钢小型材机组轧制弹簧扁钢与轧制圆钢(带肋钢筋)在工艺上存在着较大差异,传统轧制的电气控制不能满足当前轧制弹扁的要求.为此对制约轧制弹簧扁钢的电气技术进行了改造,实现了轧制棒线和弹簧扁钢工艺的更换.  相似文献   

3.
文章介绍了热轧钢板的生产、冷轧钢板(包括镀层板)和复合板的生产、型材轧制的生产、钢管和冷弯型材的生产、金属制品的生产、辊子和接合钢筋的生产、一般问题与理论问题等。  相似文献   

4.
吴迪  赵宪明  何纯玉 《钢铁》2004,39(2):28-31
型钢生产企业欲扩大市场份额和提高经济效益,必须提高产品的尺寸精度。在钢材产量大于市场需求的条件下,高精度轧制显得更加重要。对型材的高精度轧制工艺进行研究,结果表明:欲实现型材高精度轧制,不仅需要高精度成品轧机,轧制工艺也须相应改进。采用合适轧制工艺,使用普通精度的型钢轧机,异形断面型钢的轧制尺寸精度可以达到冷加工的尺寸精度,直接轧制某些特定用途的机械零件。提高型材轧制尺寸精度,关键是l~2个成品和成品前孔型的轧制精度,并非需要全线轧机都要提高轧制尺寸精度。  相似文献   

5.
1 国外小型材生产技术的发展 全连续、无扭、微张力和无张力轧制是小型材生产技术发展的总趋势。国外小型材的生产技术也经历了从横列式向连续式小型生产的转变过程。进入50年代以来,国外新建的小型轧机大部分为全连续式轧机,特别是80年代以来,以计算机为标志的全数字化电气控制系统在小型连轧生产线上的广泛应用,使小型连轧技术的发展到了一个新  相似文献   

6.
本文介绍了合金钢坯料的准备、修靡过程与加热工艺,同时还介绍了合金钢条型材轧制的形变特性及其轧制工艺设计。  相似文献   

7.
无孔型轧制是一项可以优化线棒材生产的先进技术。本文依托新兴铸管盘螺生产机组开展了无孔型轧制工业试验和研究,具体介绍新兴铸管股份公司在高线车间粗中轧1-12^#轧机上采用了无孔型轧制工艺并介绍了其工艺特点,通过制定合理的轧制工艺参数正确的使用轧辊、导卫,解决开发中发现的问题,并分析了高线无孔型轧制技术带来的效益。实践证明,无孔型轧制技术开发成功后,可优化轧制工序,能达到统一坯料、去除氧化铁皮、节约生产时间、降低轧辊和导卫消耗、降低劳动强度和减少固定资产投入等目的。无孔型轧制技术具有广阔的发展应用前景,技术价值和经济价值较大,特别适合小型材生产的老线改造和新线建设。  相似文献   

8.
孔德彪 《特殊钢》2002,23(6):36-39
介绍了CSP(紧凑式带材生产)、ISP(在线带材生产)、FTSC(通用薄板坯连铸)等薄板坯连铸连轧的轧制设备(包括加热炉)和轧制技术-自由轧制技术、无头轧制技术和铁素体轧制技术等。  相似文献   

9.
控制轧制在厚板生产中应用广泛,但对厚板轧机的产能有很大的影响。通过使用多块钢轧制技术可以有效地解决这一问题。介绍了控制轧制的概念,以及单机架和双机架配置下不同类型的多块钢轧制技术,同时对每种轧制技术的优缺点进行了分析。最后给出了使用多块钢轧制技术的生产实绩。  相似文献   

10.
介绍了使用预控图对型材轧制质量进行控制实践,结果表明,型材实物质量明显提高,经济效益显著。  相似文献   

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The efficacy of treatment with cambendazole was tested in 1-year-old horses on a farm in Dubrovka, Ukraine. Thirty-five horses were treated. Their egg output was compared on the day of treatment and 14 days later with that of 33 untreated horses. Before treatment the mean number of eggs g-1 faeces was 614 in the controls and 766 in horses that had been treated. After 14 days the mean egg output in the controls was 580 and in the treated horses 369. This means a reduction of 54.5%. Only cyathostome larvae could be cultured from faeces collected after treatment. It can be concluded that benzimidazole resistance in cyathostomes is present in the Ukraine.  相似文献   

13.
以重庆大学、重庆邮电大学和重庆理工大学为例,剖析重庆高校推进产学研合作的基本模式,已经取得的突出成绩,分析总结其基本经验.从完善政策法规体系、强化经济调控、建立组织机构、加强中介建设及开展国际产学研合作等方面,提出了深入推进重庆高校产学研合作的对策建议.  相似文献   

14.
We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.  相似文献   

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A prospective study of fractures in 231 children received at Khartoum North Teaching Hospital(KNTH) was carried out for a period of six months. The incidence of child fracture rated as one per day, then it increased from the age of 5 years onwards in boys and between 6 and 8 years in girls. Most injuries were sustained during the day time, especially between late afternoon and sunset. 82% of injured children presented to a medical facility, while 18% were taken to native healers first. Non-road traffic accidents accounted for 84% of the fractures mainly due to sports, domestic injuries and falls; whereas road traffic accidents were 16% and occurred mainly in pedestrians. Forty three percent of the fractures needed only first aid and splintage while 42% needed closed reduction. Thirty one percent of all patients were treated as inpatients. The long bones were affected in 91% of all fractures, the commonest site being the distal end of the forearm (26%), followed by supracondylar fracture of the humerus (15.6%). In the upper limb, left-sided fractures predominated. The epiphyseal injuries were 3.5% of all fractures, mainly at the distal radial epiphysis. Boys were commonly affected between 13-15 years of age. Open fractures constituted 9.8% of the series and were mainly due to traffic accidents in town dwellers, the most vulnerable bones were those of the leg and foot. Pathological fractures accounted for 2.2% and were due to bone cysts and osteogenesis imperfecta. The problem of child safety and the preventive measures need to be more stressed.  相似文献   

18.
Certain patients enter psychoanalysis because of their inability to love another person. Often they report a repetitive erotic pursuit of desired partners, without being able to experience or maintain loving feelings. Kernberg has understood such difficulties as representing effects of early narcissistic disappointments and/or of difficulties in resolving oedipal conflicts. In this paper, Lacanian concepts of the mirror phase and symbolic love are employed to develop these issues. Sexualization of problems in mirroring may be fused with oedipal conflicts in some cases. An extended vignette is presented to illustrate the technical and theoretical issues.  相似文献   

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A model is presented in which ion translocation through the F0 part of the ATP synthase drives the rotation of the ring of c subunits (rotor) versus the a subunit (stator). The coupling ion binding sites on the rotor are accessible from the cytoplasm of a bacterial cell except for the c subunit at the interface to the stator. Here, the binding site is accessible from the periplasm through a channel formed by subunit a. In the ATP synthesis mode, a coupling ion is anticipated to pass through the stator channel into the binding site of the adjacent rotor subunit, following the electrical potential. Occupation of this site triggers, probably by electrostatic forces, the rotation of the ring. This makes the binding site accessible to the cytoplasm, where the coupling ion dissociates. Simultaneously, this rotation moves again an empty rotor subunit into the contact site with the stator, where its binding site becomes loaded and rotation continues.  相似文献   

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