一起TNT碱性废水沉淀池火灾事故分析

某化工厂TNT碱性废水沉淀池在清理过程中发生了火灾事故,在现场调查的过程中,从附着在沉淀池上的可燃物成分入手,详细分析了造成此次火灾事故的主要原因,并在假定附着在池壁及立柱上的红棕色物质为纯TNT和事故中TNT为等容、绝热燃烧的前提下,计算出了事故中TNT燃烧的最高温度及最大压力.对类似工程中的防火防爆工作提供参考.     

WFQ的性能分析及改进

定量分析了WFQ在不同信道利用率情况下和各等级业务负载分布变化时的性能变化。研究发现，WFQ本身具有一定的抗高等级业务突发的能力，其性能不仅与业务负载分布有关，而且与信道利用率和各服务等级权值之间的比例关系有关，提出了一种基于测量的可变权值的WFQ调度算法，根据信道利用率和各等级负载分布的变化调整各等级的权值，最后通过仿真，将这两种算法在比例区分服务模型PDS（Proportional Diferentiated Service)下进行了比较，仿真结果证明基于测量的WFQ在各等级业务负载正常分布的情况下性能比WFQ更好，在保证高等级业务的时延和时延抖动很小的情况下，抗高等级业务突发的能力更好。     

Active worm countermeasure based on detection

在分析了现有网络蠕虫遏制技术的不足的基础上,提出了一种基于检测驱动的网络蠕虫主动遏制模型:利用网络蠕虫检测技术,在网络出口设置探头对进出网络的数据包进行捕包检测,如发现网络蠕虫的感染主机,则利用网络的漏洞对网络蠕虫进行清除并且修补漏洞;同时采用漏洞扫描的方式对网络内的主机进行扫描,如发现存在漏洞的主机,对漏洞进行修补或对主机进行免疫,以达到防止网络蠕虫感染的目的.给出了这种主动遏制策略的数学模型,从理论上分析了主动遏制过程中各种参数之间的作用关系,为之后的具体策略研究提供了理论基础.     

逆布雷顿循环微型低温制冷机

在目前广泛采用的低温制冷循环中,以透平机械为主的逆布雷顿循环制冷机有望能够满足卫星,宇宙飞船等航天器上低冷量,高性能,高效率的特殊要求,成为空间制冷的一种选择,总结了近几年空间用逆布雷顿循环制冷机的研究成果,表明由ＤＣ－ＡＣ转换器,微型离心式压缩机,微型透平膨胀机及高效紧凑式换热器组成的微型逆布雷顿循环制冷机是一种有前途的微低温制冷机。     

Enhanced green emission from Tb-Bi co-doped GdAlO3 nanophosphors

Bi³⁺ and Tb³⁺ ions co-doped GdAlO₃ (GAP) nanophosphors have been synthesized by means of solvothermal reaction method. The XRD pattern of GAP phosphor confirms their orthorhombic phase. The luminescence properties of these phosphors have been explored by analyzing their excitation and emission spectra along with their decay curves. The excitation spectra of GAP:Tb³⁺, Bi³⁺ phosphors consist of a broad band in the shorter wavelength region due to the 4f⁸ → 4f⁷5d¹ transition of Tb³⁺ ions overlapped with the 6s² → 6s¹6p¹ (¹S₀ → ³P₁) transition of Bi³⁺ ions and some sharp peaks in the longer wavelength region due to f → f transitions of Tb³⁺ ions. The present phosphors exhibit green color due to strong ⁵D₄ → ⁷F₅ transition of Tb³⁺ ions. The emission intensity was enhanced by co-doping with Bi³⁺ ions under 292 nm excitation, which indicate that the efficient energy transfer occurred from Bi³⁺ to Tb³⁺ ions.     

Different shape of GaAs quantum structures under various growth conditions

We report the influences of growth parameters on the characteristics of GaAs quantum rings (QRs) and quantum dots (QDs) formed on AlGaAs/GaAs by the droplet epitaxy (DE) method. After forming Ga droplets on the AlGaAs/GaAs surface, varying amounts of arsenic (As) flux were introduced to fabricate the GaAs quantum structures. By decreasing the As flux from 8 × 10^− 5 to 3 × 10^− 5 Torr, the shape of the GaAs quantum structures was changed from QDs to elongated QRs. With further decreasing As flux, the shape of the elongated QRs became symmetric. The formation characteristics of the GaAs QRs from the QDs with the amount of As flux were discussed in terms of migration behaviors of the gallium (Ga) atoms on the GaAs(001)-c(4 × 4) surface. The effects of the amount of Ga supply and the growth temperature for the deposition of Ga droplets on the formation of the GaAs quantum structures were also considered.     

石膏型渗流制备泡沫铝填充圆管压缩行为研究

采用石膏型渗流制备开孔泡沫铝并填充到薄壁圆管,制成泡沫铝夹心管.通过准静态压缩试验研究了泡沫铝夹心管的压缩行为.结果表明:采用石膏型渗流法制备的泡沫铝孔隙率在85％左右,其压缩变形阶段可分为弹性段、塑性平台段和致密化段;空心圆管的压缩行为与其本身的结构参数有关;泡沫铝夹心管的力学性能与吸能能力比空心圆管和泡沫铝有了一定...     

热电材料研究的最新进展

热电材料是一种能将电能与热能相互转换的功能材料,近年来备受关注.从块体热电材料、低维热电材料、热电器件及其应用等方面综述了热电材料研究的最新进展,并展望了今后的发展方向.     

Integrated liquid crystal optical switch based on double teeth-shaped structure at telecom wavelengths

The characteristics of a double teeth-shaped plasmonic optical switch are analyzed. Based on the metal–insulator–metal waveguide consisting of double rectangular teeth, a nanoscale liquid crystal optical switch is proposed and numerically simulated by using the finite difference time domain method with a perfectly matched layer absorbing boundary condition. It is found that the double teeth-shaped structure filled with liquid crystal can realize the function of a switch. The modulation depth of the double teeth-shaped structure is larger than 50?dB.