中国古代金的分析技术

归纳总结了中国古代金分析技术的主要成果和与其相关的重要事件，对于认识金的分析技术的起源有一定的参考意义。     

浅谈如何做一名新时期创新型教师

教师的职业道德是贯穿教育全过程的精神支柱,它对学生和社会都会有深远的激励和影响作用;而熟练掌握专业知识和教育理论知识是教师业务能力的本质要求。新时期的创新型教师都必须不断地在这两个方面进行提升才能够符合时代的要求。     

温度对Ni—P化学镀层结合力影响的研究

用弯曲法、划痕法研究了镀后加热温度对Ni-P化学镀层结合力的影响,结果表明:镀后退火温度越高,镀层结合力越好,但温度过高时,镀层硬度将下降。用金相观察及电子探针分析,探讨了镀后退火温度影响结合力的机理。结果指出:退火时将在镀层和基体界面上发生Ni与Fe的互扩散,形成Ni-Fe合金扩散层,从而提高了结合力。为了能在保证镀层硬度的前提下提高结合力,本文提出了二次镀覆的设想,获得较好试验结果。     

多孔β-TCP陶瓷药物载体的制备与体外释药速率的研究

本文用注浆成形的方法制备了以β-TCP为主晶相的多孔药物载体，体外测定了利福平的释药速率。实验结果表明，利福平在模拟体液中能够达到稳定的释放，可以作为骨结核手术后的辅助治疗。多孔β-TCP药物载体有望成为一种理想的药物缓释载体。     

Dielectric properties of polyarylate (PAr) around the glass transition

Dielectric characterization of the α-relaxation in polyarylate (PAr) has been carried out by means of a dielectric spectroscopy technique in a frequency range of 10–30 kHz. Complementary thermally stimulated depolarization currents (TSDC) and differential scanning calorimetry d.s.c.) measurements have also been performed. The results are interpreted in terms of the standard Cole-Cole plot and Havriliak-Negami distribution for the dielectric relaxation times. Information about the temperature and frequency dependence of a.c. conductivity is also obtained from the experimental curves. However, the behaviour of the main dielectric relaxation time is deduced from the experimental data in a wide range of temperature around the glass transition. This behaviour results in close agreement with the theoretical predictions of a free-volume approach for the dielectric α-relaxation recently proposed by the authors.     

Interpretation of quasi-elastic light scattering data for flexible chains: model dependence

The autocorrelation functions and corresponding relaxation times obtained from the forward depolarized quasi-elastic light scattering experiment are exhibited for two quite similar models of flexible polymer chains in solution. A very small change in the chain dynamics is found to be sufficient to change the relaxation time from a relatively short time independent of chain length, with an autocorrelation function suggestive of an unweighted sum of contributions from all the relaxation times in the spectrum of chain motion, to a long time with an autocorrelation function identical with that for the end-to-end vector, strongly dependent upon chain length and dominated by the longest relaxation time in the spectrum. These results raise the question whether widely-used models in which information about short-range chain structure and motion is deliberately omitted can be expected to be appropriate for the interpretation of depolarized scattering experiments.     

Impact of class clustering in a multiclass FCFS queue with order-dependent service times

In multi-class queueing systems, customers of different classes can enter the system. When studying such systems, it is traditionally assumed that the different classes of customers occur randomly and independently in the arrival stream of customers in the system. This is often in contrast to the actual situation. Therefore, we study a multi-class system with so-called class clustering in the customer arrival stream, i.e., (Markovian) correlation occurs in the classes of consecutive customers. The system under investigation consists of one server that is able to serve two classes of customers. In addition, the service-time distribution of a customer depends on the equality or non-equality of its class with the class of the previous customer. This latter feature occurs frequently in practice. For instance, execution of the same task again can lead to both faster or slower processing times. The first case can occur when the execution of a different task entails resetting a machine, or loading new data, et cetera. The opposite situation appears, for instance, when execution of the same task requires postprocessing (such as cooling down or reinitialization of a machine). We deduce the probability generating function (pgf) of the system content, from which we can extract various performance measures, among which the mean values of the system content and the customer delay. We demonstrate that class clustering has a tremendous impact on the system performance, which highlights the necessity to include it in the performance assessment of any system in which it occurs.     

A novel algorithm for layout optimization of injection process with random demands and sequence dependent setup times

Injection molding is an ideal manufacturing process for producing high volumes of products from both thermoplastic and thermo setting materials. Nevertheless, in some cases, this type of manufacturing process decelerates the production rate as a bottleneck. Thus, layout optimization plays a crucial role in this type of problem in terms of increasing the efficiency of the production line. In this regard, a novel computer simulation–stochastic data envelopment analysis (CS-SDEA) algorithm is proposed in this paper to deal with a single row job-shop layout problem in an injection molding process. First, the system is modeled with discrete-event-simulation as a powerful tool for analyzing complex stochastic systems. Then, due to lack of information about some operational parameters, theory of uncertainty is imported to the simulation model. Finally, an output-oriented stochastic DEA model is used for ranking the outputs of simulation model. The proposed CS-SDEA algorithm is capable of modeling and optimizing non-linear, stochastic, and uncertain injection process problems. The solution quality is illustrated by an actual case study in a refrigerator manufacturing company.     

Modeling and solving mixed-model assembly line balancing problem with setups. Part I: A mixed integer linear programming model

This paper is the first one of the two papers entitled “modeling and solving mixed-model assembly line balancing problem with setups”, which has the aim of developing the mathematical programming formulation of the problem and solving it with a hybrid meta-heuristic approach. In this current part, a mixed-integer linear mathematical programming (MILP) model for mixed-model assembly line balancing problem with setups is developed. The proposed MILP model considers some particular features of the real world problems such as parallel workstations, zoning constraints, and sequence dependent setup times between tasks, which is an actual framework in assembly line balancing problems. The main endeavor of Part-I is to formulate the sequence dependent setup times between tasks in type-I mixed-model assembly line balancing problem. The proposed model considers the setups between the tasks of the same model and the setups because of the model switches in any workstation. The capability of our MILP is tested through a set of computational experiments. Part-II tackles the problem with a multiple colony hybrid bees algorithm. A set of computational experiments is also carried out for the proposed approach in Part-II.