科创中国

Bearing ring is the crucial component of bearing. With regard to such problems as material waste, low efficiency and high energy consumption in current process of producing large bearing ring, a new process named "casting-rolling compound forming technology" is researched by taking the typical 42CrMo slew bearing as object. Through theoretical analysis, the design criteria of the main casting-rolling forming parameters are put forward at first. Then the constitutive relationship model of as-cast 42CrMo steel and its mathematical model of dynamic recrystallization are obtained according to the results of the hot compression experiment. By a coupled thermal-mechanical finite element model for radial-axial rolling of bearing ring, the fraction of dynamic recrystallization is calculated and recrystallized grains size are predicated. Meanwhile, the effects of the initial rolling temperature and feed rate of idle roll on material microstructure evolution are analyzed. Finally, the industrial rolling experiment is designed and performed, based on the simulation results. In addition, mechanical and metallographic tests are conducted on rolled bearing ring to get the mechanical parameters and metallographic structure. The experimental data and results show that the mechanical properties of bearing ring produced by casting-rolling compound forming technology are up to industrial standard, and a qualified bearing ring can be successfully formed by employing this new technology. Through the study, a process of forming large bearing ring directly by using casting ring blank is obtained, which could provide an effective theoretical guidance for manufacturing large ring parts. It also has an edge in saving material, lowering energy and improving efficiency.

As the popularization of dual ring fieldbus,the optimized dual ring synchronization methods are still in short.The current synchronization methods are generally established in traditional industrial fieldbus,in which transmission is commonly considered in single track,the two-way transmitting cannot take full effect,and would result in unwanted idle load on equipment lines.In stamp-transferring part,the synchronizing algorithm is not properly processed to diminish the latency,so the real-time performance of entire system cannot be ensured.To support the synchronization control of stations in the CNC system,a real-time time synchronization method for dual ring fieldbus in the CNC system is designed in this paper.In this method a synchronizing message transmission scheme based on dual ring architecture and the synchronization algorithm between master and secondary stations are integrated.In the scheme,the clock models of both master and secondary stations are optimized with corresponding modules and the stamp data transmission based on the dual ring fieldbus is devised exclusively,so the transmitting efficiency improves with less idle work.In the algorithm,all the secondary stations can accomplish the consistent state with master station by updating clock discrepancy information in one communication cycle,and it takes the advantage of two-way transmitting and makes the best use of dual ring structure,so the real-time performance of the system can be promoted while retaining the precision of synchronization.To evaluate the performance,the costs of the method and errors during synchronizing are noted and analyzed based on the actual running environment in the industrial fieldbus.The results show that it reduces communication cost and ensures the smoothness of the system with low lag effects under heavy load.The proposed time synchronization method optimizes the architecture of sync message transmission in dual ring fieldbus,and improves the efficiency of time synchronization in the stations of CNC system.

目的 探讨胃癌组织及癌旁正常组织中细胞分裂周期蛋白42(cell division cycle 42, Cdc42)和β1整合素的表达及临床意义.方法 采用免疫组化SP法检测60例胃癌及相应癌旁组织中Cdc42、β1整合素的表达,并复习相关文献.结果(1)Cdc42、β1整合素在胃癌中的阳性率分别为70.0%和90.0%,均高于癌旁正常组织(26.7%和36.7%),两组相比差异有统计学意义(P〈0.05);(2)Cdc42与β1整合素的表达均与肿瘤的浸润深度、分化程度、淋巴结转移及TNM分期呈正相关(P〈0.05),与其他临床病理参数无关;(3)Cdc42与β1整合素的表达有关联(χ2=4.268,P=0.039〈0.05,rs=0.267).结论 Cdc42与β1整合素在胃癌组织中表达呈正相关,二者在胃癌组织中不同程度的表达与胃癌的发生、发展密切相关.

介绍了机械式紧密纺的作用原理,对比了机械式、负压式紧密纺的优缺点.叙述了机械式紧密纺在上海-企业中的应用实例,对老机进行机械式紧密纺改造投资少、见效快,有节能和环保优势,具有推广潜力.

目的 探讨上调糖皮质诱导型蛋白激酶(SGK-1)能否保护Aβ1~42诱导的细胞毒性及其保护机制.方法 在HEK293细胞中给予不同浓度Aβ1 ~42聚集体处理,摸索合适的诱导细胞毒性的浓度.HEK293细胞转染SGK-1质粒24h后再给予Aβ1~42处理24h,通过细胞活性分析以及Western印迹实验检测凋亡相关通路变化.结果 过表达SGK-1能够明显改善HEK293细胞由Aβ1~42诱导的细胞毒性(P<0.05),SGK-1的上调伴随着JNK-1 (P <0.01)和Caspase-3的抑制(P<0.05).结论 上调SGK-1可能通过抑制JNK-1的激活从而抑制Caspase-3的活化来保护细胞,上调SGK-1可以作为治疗阿尔茨海默病(AD)患者Aβ细胞毒性的保护靶点.