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1.
 在自制的销盘式干滑动摩擦磨损实验机上研究了45CrNiMoVA与PCrNiMo配副的摩擦磨损特性。结果表明:材料的磨损率随着速度、载荷的增加而增大;摩擦因数随着载荷增加而减小;随着速度的改变磨损率的变化规律为:减小、增大、再减小;硬度对实验材料磨损率的影响与通常所用材料不同,磨损机理为磨粒磨损和粘着磨损。  相似文献   

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张学浩 《山西冶金》2006,29(3):18-20
介绍了对45优质碳素结构钢开发试验情况。为中小钢厂在炉外精炼条件不完善的情况下,开发各种优质钢的过程中出现的各类问题的解决提供了借鉴。  相似文献   

4.
根据45钢液相线温度低、固液共存两相区宽及铸坯坯壳高温强度低的凝固特性和3^#连铸机现有的设备状况。确定了浇注温度、拉速及二次冷却配水量等工艺参数。把浇注温度下限上调5℃,控制在1515℃-1525℃,拉速控制在1.6—1.7m/min,经过低倍检验铸坯质量良好,符合实际生产要求。  相似文献   

5.
SG45钢是在45号钢基础上开发的1种新型的非调质钢,通过对成品棒材进行取样,分析了SG45的化学成分,在光学显微镜及扫描电镜下研究了不同状态下酸浸后的金相样品,研究了钢材组织及夹杂物的分布情况,并对试样进行了拉伸、冲击试验以分析其不同状态下的力学性能。比较了不同状态下SG45钢和45号钢的组织及力学性能,SG45钢作为1种替代性非调质钢,其抗拉强度为472MPa、硬度为230HBW、冲击值为45J、伸长率为36.5%。  相似文献   

6.
The reactivity of the antibovine monoclonal antibodies (mAbs) comprising temporary cluster TC1 was compared with that of two OvCD45R mAbs on sheep cells. Three of the mAbs--CC31, CC99 and CC103--did not cross-react with sheep cells. All the workshop mAbs precipitated two molecules of apparent molecular weight (MW) 200 kDa and 220 kDa while the antisheep CD45R mAb 20-96 precipitated a single band of 220 kDa. Cell surface expression was examined by single colour FACS (fluorescence activated cell sorting) analysis of efferent and afferent lymph cells and peripheral blood lymphocytes and the distribution of the antigens on CD4+, CD8+ and T19+ (WC1) and B cells was determined by two colour fluorescence staining. By cellular distribution and immunohistology the TC1 mAbs could be divided into four distinct groups which differed from a fifth group comprising the two OvCD45R antibodies.  相似文献   

7.
The high yield strength and elastic modulus of metallic glasses suggests they could perform an important role in structural applications. To produce materials with a high strength-to-weight ratio and excellent mechanical energy absorption, it is advantageous to form amorphous alloys as cellular solids. Using the elastic properties of slip cast amorphous Fe45Ni45Mo7B3 ribbons, a metallic glass honeycomb was manufactured with a unique manufacturing approach. First, prototypes were manufactured with a porosity of 97?pct, a cell wall thickness of 0.03?mm, and a cell size of 3?mm. Experimentally measured mechanical properties were reasonably similar to analytical models. This suggests that a three-times improvement in the yield strength along the out-of-plane direction is achievable when compared with crystalline aluminum honeycombs. An analytical model was developed to predict the relative density and the compressive stress (?? 3 * ) in the out-of-plane (X 3) direction of the ??teardrop?? cellular structure. The predictions are validated by initial experimental results and compare well with existing analytical models for hexagonal cellular materials.  相似文献   

8.
Swine cell binding analyses of a set of 48 monoclonal antibodies (mAbs), including eleven standards, assigned to the CD44 and CD45 subset group of the Second International Swine CD Workshop yielded 13 clusters. Although none of these corresponded to CD44, seven mAbs formed a cluster which was identified as being specific for restricted epitopes of CD45 (CD45R). In addition, a T-cell subset specific cluster comprised of four mAbs was also identified. Two mAbs (STH106 and SwNL 554.1) reacted exclusively with CD8 bright lymphocytes, the other two (2B11 and F01G9) with a subset of CD4 lymphocytes. The other 10 clusters were either specific for MHC-class I like molecules or overlapped with clusters identified by the adhesion molecule subgroup and are therefore just briefly discussed in this report. The specificity of all the mAbs in the CD45R cluster was verified by their ability to immunoprecipitate distinct proteins and to react with CHO cells expressing individual isoforms of CD45. Three CD45R mAbs (3a56, MIL5, -a2) did react with a 210 kDa isoform(s), while another three (STH267, FG2F9, 6E3/7) only recognized a 226 kDa isoform(s). The remaining one (MAC326) precipitated both a 210 and 226 kDa protein. The specificity of all the mAbs in the CD45R cluster, and of the CD45 common mAbs, was confirmed by their reactivity with CHO cells transfected with cDNAs encoding the extracellular and transmembrane portions of distinct CD45R isoforms. Those mAbs recognizing a 210 kDa protein reacted with CHO cells expressing the CD45RC isoform, while those capable of precipitating a 226 kDa, but not the 210 kDa, polypeptide recognized CHO cells expressing either the CD45RAC and the relatively rare CD45RA isoform. MAC326 was unique in its inability to react with CHO cells engineered to produce the CD45RC and CD45RAC isoforms. Thus, three mAbs (6E3/7, STH267, and FG2F9) appear to be specific for an epitope(s) encoded by the A exon, while one (MAC326) recognizes a determinant encoded by the C exon. The remaining three mAbs (3a56, -a2, MIL5) are apparently specific for an epitope(s) which results from the fusion of the C exon to the invariant leader sequence and is destroyed by inclusion of the A exon. All three CD45 common mAbs, K252.1E4, MAC323 and 74.9.3, did react with the CHO cells lines expressing either the CD45RA, CD45RC, CD45RAC or CD45RO isoforms, but not with untransfected CHO cells. When the natural expression of CD45 isoforms was examined by reacting lymphocytes with CD45R mAbs, a high level expression of isoforms containing the A exon-generated domain was detected in all B cells while the majority of CD4+ T cells had undetectable or lower expression density of this protein than B cells. In contrast, the density of expression of the CD45 isoform(s) containing the C exon-generated domain ranged from undetectable to high in CD4+ T cells whereas the amounts were approximately ten-fold lower in B cells. Overall this panel of CD45 mAbs will be very useful in analyzing the maturation and differentiation of swine lymphoid cells subsets.  相似文献   

9.
韶钢炼轧厂生产的 45号钢在常规生产检验中发现材料规格对力学性能初检合格率有影响 .为此 ,随机抽取16、18、2 8、3 0mm 4个规格、11个炉号的 45号钢进行正火工艺试验 ,探讨了正火工艺对 45号钢力学性能的影响 .结果表明 :直径小于 2 5mm的 45号钢 ,正火工艺采用GB/T699- 1999标准推荐的工艺执行 ,即 85 0℃×40min ,力学性能达到标准要求 ;直径大于或等于 2 5mm的 45号钢 ,正火工艺采用 880℃× 3 0~ 60min也可达标 .金相检验表明 :这两种工艺处理试样的金相组织均为块状铁素体和大小均匀的珠光体 ,这种组织能够满足强度和塑性的理想配合  相似文献   

10.
Flow cytometry is a powerful tool for immunophenotyping of acute leukemia. Gating of leukemic cells is currently performed on the two dimensional display of forward scatter (FSC) and side scatter (SSC). However, this gating method can not discriminate leukemic cells from contaminated normal cells. Therefore, we used a CD45 monoclonal antibody to detect leukemic cells (CD45dlm cells) in combination with the SSC parameter. This CD45-SSC gating method was very useful for immunotyping of AML and ALL, especially leukemia with a low percentage of blasts. We recommend this new gating method for more accurate immunophenotyping of acute leukemia.  相似文献   

11.
为了了解45A钢铸坯夹杂物行为,利用显微镜、电子探针和大样电解等分析方法对45A钢铸坯中夹杂物分布、数量和种类做了分析。结果表明:铸坯夹杂物整体控制水平较好,其中铸坯夹杂物指数平均为22.2个/mm2,铸坯中心夹杂物指数为25.8个/mm2;铸坯大样电解结果表明大型夹杂物总量平均为2.23 mg/(10 kg),夹杂物直径都大于300μm;大型夹杂物主要来源于结晶器卷渣、氧化产物和中间包覆盖剂等。  相似文献   

12.
南钢45号钢的主要问题是铸坯和轧材裂纹率高,轧材易在热墩或热墩后的机加工过程中出现不同程度的开裂。究其原因是由于钢中大量的氧化物和硫化物夹杂使得其塑性、韧性及疲劳强度降低、加工性能变坏所致。因此,通过控制转炉终点碳质量分数和出钢过程温度、增加软吹氩时间、在LF炉中提前造白渣以及加强保护浇注等措施,降低了45号钢钢中夹杂物的数量,有效的避免了加工开裂。  相似文献   

13.
Forty-five patients with Williams syndrome (WS) were evaluated for oral abnormalities. The mean age of the patients was 9.25 years, the median age was 6.7 years, and the majority (62.2%) were male. Hypodontia was present in 11.1% of the patients. Abnormal tooth morphology was noted in 12.5% of the primary dentitions and 40.7% of the permanent dentitions. With the exception of the primary mandibular central incisors of males, all mesiodistal incisor crown dimensions were statistically significantly smaller when compared with norms (P < 0.05). At least one hypoplastic enamel defect was present in 9.4% of patients with primary teeth and in 18.5% with permanent teeth. No patients exhibited generalized enamel hypoplasia. More than half of the patients (59.1%) were both caries and restoration free, while only 13.6% presented with clinically active caries. Tongue thrusting was present in 67.7% of the sample, while more than 50% of the patients present with excessive interdental spacing. Patients exhibited a higher than normal prevalence of Class II and III occlusions, open and deep bites and anterior crossbites. No single dental finding was pathognomonic of WS, however two constellations of findings, each occurring in approximately one-third of the sample, were observed: 1) microdontia, anterior crossbite, tongue thrusting, and excessive interdental spacing, and 2) microdontia, deep or open bite, and excessive interdental spacing.  相似文献   

14.
The flow in a junction manhole is analyzed using hydraulic modeling and a semiempirical approach. A large number of experiments was conducted to obtain insight in the complex hydraulic features of flows in either one or both of the approach junction branches. Given their significance in applications, in addition to supercritical flow conditions, junction flow with mixed approach flows were also considered. The results include information regarding the main wave structure, with detailed discussions of locations and heights of so-called waves A, B, and C. Further, the swell height at the downstream manhole end was determined and it was found that choking of the supercritical flow structure occurs mainly because of a capacity limit at this outlet. Then, both the minimum and maximum flow limitations were determined. If the discharge is smaller than the minimum discharge, there is a transition from supercritical to subcritical junction flow. If, on the other hand, the discharge is larger than the maximum discharge, supercritical junction flow breaks down and a pressurized two-phase flow is established, which can be responsible for dangerous phenomena such as manhole geysering.  相似文献   

15.
研究了大规格 45V非调质钢加热工艺、终轧温度和冷却速度等轧制工艺对综合力学性能的影响。并研究了获得良好综合力学性能而优化的轧制工艺  相似文献   

16.
介绍了安钢第二炼钢厂45号钢的生产工艺,确定了45号钢工艺参数及控制措施。  相似文献   

17.
针对45#硬线由Φ6.5 mm拉拔到Φ4.6 mm时发生断裂的问题,分析了其拉拔断口及表面裂纹形貌,用金相显微镜、扫描电镜对其金相组织、夹杂物及化学成分进行分析,结果表明:45#硬线钢中存在大颗粒脆性夹杂物,降低了盘条表面的强度和塑性,使其在拉拔过程中出现横裂纹,继而引起拉拔断裂,盘条表层组织不均匀也增加了盘条断裂机率。提出了夹杂物控制和金相组织改进措施,改进后盘条拉拔到Φ3.8 mm时的断丝率不足1.5%。  相似文献   

18.
针对传统AOD配气方式的缺点,研究了基于魏季和等的脱碳精炼数学模型的配气模型,使AOD脱碳配气可根据钢水碳含量的变化自动调整氧氩比、根据钢水温度变化自动调整供氧强度,以及根据炉役中炉容比的变化自动调整最大供氧强度。该模型应用于AOD不锈钢冶炼系统中,既提高了氧气利用率,又缩短了冶炼时间,而且吨钢氧耗和还原硅消耗也略有改善,取得了较好的效果,为AOD不锈钢冶炼智能化打下了良好的基础。  相似文献   

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郑果  田新喜  武炜 《山西冶金》2015,(3):87-88,91
介绍了山东石横特钢集团有限公司炼钢厂45 t转炉留渣操作工艺以及留渣操作工艺产生喷溅的预防措施。留渣操作工艺的应用,减少了石灰消耗、金属料耗,缩短了冶炼周期,延长了炉体寿命,不仅对钢铁企业产生了持续的经济效益,对节能减排也做出了贡献。  相似文献   

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