表调工艺条件对冷轧汽车板锌系磷化膜耐腐蚀性能的影响

以耐硫酸铜点滴时间作为评判冷轧汽车板锌系磷化膜耐腐蚀性能的依据,通过单独分析表调液温度、表调液浓度和表调时间对耐硫酸铜点滴时间的影响,得到最佳表调工艺条件为:表调液温度30℃、表调液浓度4 g/L、表调时间35 s。结果表明:在最佳表调工艺条件下的磷化膜耐硫酸铜点滴时间达到185 s,较未表调处理的磷化膜耐硫酸铜点滴时间(142 s)明显延长。在最佳工艺条件下进行表调处理延长了磷化膜耐盐雾时间,磷化膜表现出较强的耐盐雾腐蚀能力,优于未表调处理的磷化膜。盐雾试验前后,磷化膜的主要成分没有明显变化。

40Cr钢表面锌-锰系磷化膜的制备与耐腐蚀性能研究

采用中温锌-锰系磷化工艺,按照三因素四水平正交试验方案,在40Cr钢表面制备了16种锌-锰系磷化膜。通过硫酸铜点滴实验,测试了磷化膜的耐腐蚀性能,进行了最优工艺参数的筛选。分析了最优工艺条件下制备的磷化膜的元素组成,并观察了最优磷化膜和40Cr钢浸泡腐蚀前后的形貌。结果表明,正交试验极差分析得到各因素对磷化膜耐硫酸铜点滴时间影响的主次顺序为:磷化液温度>磷化时间>表调时间。当表调时间为30 s、磷化时间为25 min、磷化液温度为65℃时,磷化膜的耐硫酸铜点滴时间最长,耐腐蚀性能最好。最优磷化膜主要由Zn、P、Mn、Fe和O元素组成,Zn元素含量最高,约为38%;最优磷化膜浸泡腐蚀前后的形貌变化不大,能有效减轻40Cr钢的腐蚀程度。

Group scheduling with general position-dependent effect

In order to investigate more realistic group scheduling problems with position-dependent effects,the model of general position-dependent group scheduling is proposed,where the actual group setup times and actual processing times are described by general functions of the normal group setup time and position in the sequence.These general functions are not assumed to have specific function structures,and are not restricted to be monotone.By mathematical analysis and proof,each considered problem is decomposed into a group scheduling process and a job scheduling process,and each scheduling process is transferred into the classic assignment problem or the classic single-machine sequence problem,and then the computational complexity to solve the considered problem is analyzed.Analysis results show that,even with general position-dependent job processing times,both the single machine makespan minimization group scheduling problems and the parallel-machine total load minimization group scheduling problems remain polynomially solvable.

Rescheduling Problems with Bicriteria

In the rescheduling on a single machine,a set of original jobs has already been scheduled to minimize some cost objective,when a new set of jobs arrives and creates a disruption.The decision maker needs to insert the new jobs into the existing schedule without excessively disrupting it.In this paper,we consider hierarchical optimization between the scheduling cost of all the jobs and the degree of this disruption.For every problem,we provide either a polynomial time algorithm or an intractable result.

Simultaneous scheduling of machines and automated guided vehicles in flexible manufacturing systems using genetic algorithms

The problem of simultaneous scheduling of machines and vehicles in flexible manufacturing system (FMS) was addressed.A spreadsheet based genetic algorithm (GA) approach was presented to solve the problem.A domain independent general purpose GA was used,which was an add-in to the spreadsheet software.An adaptation of the propritary GA software was demonstrated to the problem of minimizing the total completion time or makespan for simultaneous scheduling of machines and vehicles in flexible manufacturing systems.Computational results are presented for a benchmark with 82 test problems,which have been constructed by other researchers.The achieved results are comparable to the previous approaches.The proposed approach can be also applied to other problems or objective functions without changing the GA routine or the spreadsheet model.

Hybrid Task and Message Scheduling in Hard Real Time Distributed Systems over FlexRay Bus

FlexRay is a vehicular communication protocol designed to meet growing requirements in hard real time automotive systems and to support time triggered as well as event triggered paradigms. Thus, there has been a lot of recent interest in timing analysis techniques in order to provide bounds for the message communication times on FlexRay. In this paper, we present an approach to compute the WCRT （worst case response time） for periodic and sporadic tasks, within a FlexRay node, responsible for sending messages on the FlexRay SS （static segment） and DS （dynamic segment）. On the other hand, we propose a scheduling table for messages transmitted over the FlexRay SS. An interesting innovation would be the use of a scheduling algorithm performed on a FlexRay node to guarantee the arrival of the right data on the right time and to ensure that every task meets its deadline. As application, we will use the extended SAE （society of automotive engineers） benchmark for the FlexRay network to identify the static and dynamic tasks, and calculate the response time, based on a hybrid scheduling model to further prove that the deadline of the SAE benchmark applications is insured.

Accelerated Particle Swarm Optimization for Controlling Virtual Power Plant Consisting of Renewable Energy Sources

RES （renewable energy sources）, such as wind and photovoltaic power plants, suffer from their stochastic nature that is why their behavior on market is very delicate. In order to diversify risk, a concept of VPP （virtual power plant） has been developed. The VPP is composed of several RES, from which at least one of them is fully controllable. Because the production of noncontrollable RES can not be forecasted perfectly, therefore an optimal dispatch schedule within VPP is needed. To address this problem, an APSO （accelerated particle swarm optimization） is used to solve the constrained optimal dispatch problem within VPP. The experimental results show that the proposed optimization method provides high quality solutions while meeting constraints.

Changes of Bone Remodeling-related Factors of HPDLF Regulated by Estrogen and Tensile Strain

Estrogen deficiency has been proposed as a risk factor for alveolar bone loss, but whether or not estrogen will influcence the bone rebuilting process during orthodontic tooth movement and what the mechanisms involved remain unclear. The paper aims to provide new information that may elucidate the modulatory effect of estrogen on the bone-resorbing cytokines RANKL and its anti-resorptive factor OPG secrected by HPLFs which are already force-stimulated. The expression of OPG mRNA is rising after mechanical loading either with or without stimulated by estrogen before. But HPDL cells exposured to estrogen for 24 h before loaded tend to express more OPG mRNA. Compared with the no-estrogen group, the inhibit trend of RANKL mRNA is much more apparent in with-estrogen group. Moreover, estrogen and mechanic force time-dependently increased OPG expression and attenuated the RANKL expression.