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121.
122.
In this article, we consider a geometric process model for M/PH(M/PH)/1/K queue with new service machine procurement lead time. A maintenance policy (N???1,?N) based on the number of failures of the service machine is introduced into the system. Assuming that a failed service machine after repair will not be ‘as good as new’, and the spare service machine for replacement is only available by an order. More specifically, we suppose that the procurement lead time for delivering the spare service machine follows a phase-type (PH) distribution. Under such assumptions, we apply the matrix-analytic method to develop the steady state probabilities of the system, and then we obtain some system performance measures. Finally, employing an important Lemma, the explicit expression of the long-run average cost rate for the service machine is derived, and the direct search method is also implemented to determine the optimal value of N for minimising the average cost rate. 相似文献
123.
通过对自贡盐化产业集群现状的分析,探讨了影响集群发展的制约因素,从理论上提出了集群发展的具体对策和措施。 相似文献
124.
The impedance of a capacitively coupled contactless conductivity detector (C4D) cell was experimentally examined for different cell parameters by alternative current impedance (ACImp). The effect of the gap between the electrodes and the length of the electrodes on the impedance behavior of the C4D cell has been studied. As a result, the impedance of C4D cell is largely defined by the length of the gap between the electrodes and the length of the electrodes. The impedance increases with increasing gap between the electrodes and the length of the electrodes. It could be found that tightly coupling of the electrodes to the outer wall of the capillary is needed. The axial contactless conductometric detector can be effectively described by the simplest possible equivalent circuitry consisting of a capacitor, resistor, a second resister and a Warburg impedance. These results are helpful to understand the impedance characteristics of C4D cell and improve its detective performance. 相似文献
125.
126.
Hye-Ju Jung Ji-Sook Hong Jeong-Kwon Suh 《Korean Journal of Chemical Engineering》2011,28(9):1882-1888
This study aimed to find a way to remove organic pollutants, phenol and humic acid in aqueous solutions using TiO2 spherical activated carbon (Ti-SPAC). The Ti-SPAC was manufactured by resin ion-exchange and a heating process. This method
was very effective not only in creating TiO2 on the surface of the supports evenly, but also in making activated carbon that has highly-developed micro pores. To estimate
whether Ti-SPAC has the proper features as a photocatalyst and adsorbent, it was examined in detail by X-ray patterns, SEM
image, EDXS, BET, EPMA. The results proved that Ti-SPAC is a very useful material for treating wastewater by photocatalysis
and absorption. 相似文献
127.
This paper investigates the influence of char-forming, flame-inhibiting and intumescent surface coatings on the post-heat flexural behavior of glass fibre-reinforced epoxy composites exposed to one-sided radiant heating. The fire performance of glass/epoxy laminates surface-coated with varied formulations was evaluated using a cone calorimeter under various external heat fluxes (25, 50 and 65 kW/m2). Self-sustained ignition was significantly delayed for fire-protected laminates relative to the control. The peak heat release rates and the time to reach this event were significantly reduced in thermally-protected laminates. In addition to the chemical nature of flame retardant chemicals present in the coatings, the time to reach the peak heat release rate and the magnitude of the total heat release were influenced by the quantity and morphology of the char formed by each type of surface coating. The post-heat flexural performance of heat-damaged laminates was determined via three-point bending. There was a significant improvement in the post-heat flexural moduli retention in thermally-protected glass/epoxy laminates. This may be due to the flame retardation efficacy of the coatings and the ability of the charred structures to reduce the heat transfer into the substrate thereby protecting the underlying composite and its mechanical integrity. 相似文献
128.
Mechanistic understanding of the functionality of organic corrosion inhibitors in acidic media is essential to knowledge-based performance optimization. In this study, we address a key issue hindering progress in this area, namely the chemical nature of the corrosion inhibitor/substrate interface. X-ray photoelectron spectroscopy (XPS) is employed to reveal the surface termination of carbon-steel, following immersion in 1 M hydrochloric acid inhibited with 2-mercaptobenzimidazole (MBI). Core level spectra indicate that the termination varies as a function of MBI concentration, with the interface consisting of MBI bound to film-free carbon-steel on highly inhibited substrates. 相似文献
129.
Amorphous tin oxide (SnOx) was cathodically deposited onto graphite electrode in a bath containing 0.1 M stannous chloride (SnCl2), 0.5 M sodium nitrate (NaNO3), and 0.4 M nitric acid (HNO3) in an aqueous solution of 50% (v/v) ethanol. The SnOx coatings grown on graphite were characterized as typical capacitive behaviors by cyclic voltammetry (CV), chronopotentiometric (CP) in 0.5 M KCl. Specific capacitance (in milli-farad per square centimeter, Ca) changes linearly with the deposition charge up to 4.5 C cm−2, and a maximum of as high as 355 mF cm−2 was obtained with the SnOx coating grown at around 5 C cm−2. For the SnOx coating deposited at 0.2 C cm−2, a maximum specific capacitance (in farad per gram, Cm) of 298 and 125 F g−1 was achieved from CVs at a scan rate of 10, and 200 mV s−1, respectively. The value of Cm significantly gets lower from 265 to around 95 F g−1 when the deposition charge increases from 0.2 to around 6.0 C cm−2. The long cycle-life and stability of the SnOx coatings on graphite via the presented cathodic deposition were also demonstrated. 相似文献
130.