A facile method for preparation of PGS@ZB‐N and gas‐sol alternating synergistic effect for fire resistance of EVA

Through the simple precipitation of palygorskite (PGS) by zinc borate (ZB) (to make PGS@ZB) and the decoration of PGS@ZB by dodecylamine (N), a novel organic‐inorganic@inorganic hybrid flame retardant of PGS@ZB‐N was prepared and was incorporated with ethylene vinyl acetate copolymer (EVA) to improve its flame retardance. The structure and morphology of PGS@ZB‐N were characterized by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), and scanning electron microscopy (SEM), and it was confirmed that the PGS@ZB‐N hybrid had been successfully prepared. The flame retardancy and burning behavior of EVA/PGS@ZB‐N/EG (EG = expandable graphite) composite were studied through thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL‐94 (by the vertical burning test), and cone calorimeter test (CCT) characterizations. The prepared EVA/PGS@ZB‐N/EG composite obtained an LOI value of 41.2% with the addition of 30 wt% PGS@ZB‐N/EG. It was found that EVA/PGS@ZB‐N/EG was protected through a gas phase and condensed phase alternating synergistic effect mechanism.     

Corrosion behavior of Cu–Sn bronze alloys in simulated archeological soil media

The corrosion behavior of synthetic Cu–Sn bronze alloys with six different Sn contents was examined through an electrochemical test and a synthetic test in a simulated corrosive medium. The mechanism of corrosion and the morphology of the corroded surfaces were characterized through field emission scanning electron microscopy equipped with energy-dispersive spectroscopy. At the corrosion potential, the corrosion behavior appears to be determined by the charge transfer step and the diffusion process. It was found that the bronze-IV (Cu–26.8Sn) specimen exhibited the best corrosion resistance, as evidenced by a low corrosion current density and a high impedance. This improvement resulted from an increase in the content of the Cu–Sn solid solution in the alloy, which was conducive to forming a relatively more protective passive film on the surface of the bronze alloy. This finding would be valuable in the anticorrosion protection of archeological artefacts after their excavation.     

Flame Front Deformation Instabilities of Filtration Combustion for Initial Thermal Perturbation

The flame front deformation instability of low-velocity filtration combustion within an inert packed bed is studied based on the initial preheating non-uniformity. Based on the experimental phenomena, an initial thermal perturbation model is numerically proposed so as to predict the deformation behaviors of the flame front instabilities. The numerical prediction indicates that the assumption of an initial thermal perturbation is a feasible explanation as the cause of the flame front inclination instability. As the initial thermal perturbation increases, the phenomena of the flame front break and shrinking instabilities could easily occur at high filtration velocity or low equivalence ratio. Moreover, the evolutions of the flame front break rate and the shrinking rate are quantitatively analyzed.     

基于中压加氢改质方案的炼油流程协同优化

中国石化北京燕山分公司(简称燕山分公司）为增产高附加值产品、提升效益，对炼油系统进行了流程协同优化。中压加氢裂化装置掺炼催化裂化柴油，由加氢裂化方案改为加氢改质方案运行，将改质柴油送入三号催化裂化装置（简称三催化装置）的提升管进行回炼；同时，将焦化蜡油改入加氢裂化装置进行加工，而蜡油加氢装置不再加工焦化蜡油以改善催化裂化原料。协同优化后，中压加氢改质装置的柴油产品十六烷值提高7个单位；三催化装置的液化气收率提高1.96百分点，汽油收率增加0.88百分点，总液体收率增加2.28百分点；高压加氢裂化装置喷气燃料产品的密度（20 ℃）降低至806 kg/m3，烟点为23.8 mm，尾油BMCI由11.8降低至10.8；蜡油加氢装置精制蜡油的饱和分质量分数提高4.68百分点，芳香分质量分数降低5.96百分点，氮质量分数降低0.06百分点，使催化裂化原料性质得以改善。通过将中压加氢改质装置的喷气燃料馏分抽出送催化裂化装置回炼，与回炼改质柴油相比，催化裂化汽油的研究法辛烷值（RON）增加1.0个单位，改质柴油十六烷值提高4.8个单位。通过全炼油板块系统性优化，燕山分公司车用柴油产品的十六烷值由53.5降低至51.5，解决了质量过剩问题。     

Mathematical modelling and numerical simulation of ordered porosity metal materials formation

Ordered porosity metal materials belong to a relatively new class of porous materials named gasars. This paper presents a mathematical model of the complex physical phenomena in the production of gasars. Analyses for heat transfer, solidification kinetics and gas diffusion were coupled to describe the formation of unique gasar structure. Several criterial functions were introduced to provide significant quantitative information about the relationship between the operating technological parameters and the final structure. The computational outcomes of the numerical simulation were compared with the characteristics of real gasar ingots. The model was applied to determine the boundary conditions that would provide approximately constant physical conditions on the solidification front. The structure sensitiveness of gasars with respect to the different technological parameters is discussed.     

中压蒸汽管道焊接质量统计分析及建议

中压蒸汽管道作为工厂的公用管网的组成部分,在生产中起着非常重要的作用,其主要用于压缩机蒸汽透平等关键工艺单元,除了对材料有特殊要求外,还要求运行可靠、管内高度洁净,因此对焊接质量提出了更高要求。结合齐鲁石化公司煤代油技术改造工程的中压蒸汽管道的施工,就焊接质量用统计分析的方法,对焊接产生的气孔、夹渣、未焊透等缺陷产生的原因及采取的控制措施进行了分析,并就今后的焊接质量控制提出建议。     

238C防盗报警系统的改进

漯河中波台自安装238C防盗报警系统以来,多次出现误报现象,严重影响了发射及其他工作的正常进行。首先对该系统的工作原理进行了简单介绍,然后对误报故障现象进行了分析、处理,并改进了电路设计中存在的不足。改进后的运行数据表明,系统误报率明显下降,达到了预期的目的。最后,对本系统的设计提出了进一步完善的建议。     

一种新型火焰安全监控系统的设计与实现

介绍了一种新型火焰安全监控系统，并详述了系统实现的方法及火焰检测部分的软硬件设计．为燃烧器的管理和燃料安全提供了一种很好的方法。     

Nonlinear Propagation of Coupling Optical Pulse under Compton Scattering in Laser Medium

After considering Kerr nonlinear effect,group velocity dispersion of host and gain distribution of active particle in laser amplifying medium,a basic equation describing propagation of the coupling optical pulse under the multi-photon nonlinear Compton scattering in the laser amplifying medium has been deduced. Besides,the profile and power spectrum of a picosecond-level super-Gaussian coupling pulse in the laser amplifying medium have been discussed when its central frequency coincides with the gain peak frequency of the laser amplifying medium.     

Scheduling Algorithms for Packet-Oriented MAC Protocols in Wireless Multimedia Systems

Future generation wireless multimediacommunications will require efficient Medium AccessControl (MAC) protocols able to guarantee suitable Qualityof Service (QoS) levels for different traffic classes whileachieving a high utilization of radio resources. This paperproposes a new scheduling technique to be adopted at the MAClevel in wireless access systems, named Dynamic Scheduling-Time DivisionDuplexing (DS-TDD), that efficiently managesvideo, voice, Web and background traffics. A theoretical approachis proposed in this paper to evaluate the DS-TDD performance withvoice and Web traffics. Simulation results have permitted tohighlight the following promising characteristics of the DS-TDDscheme: (i) a high capacity of real-time traffics isattained with a QoS insensitive to Web and background trafficloads; (ii) a high throughput can be guaranteed whilepreserving the QoS levels of the different traffic classes;(iii) heavier downlink traffic loads do not modify the QoSof uplink traffics. Finally, extensive comparisons with differentscheduling schemes proposed in the literature have permitted tohighlight the better performanceof DS-TDD.