基于Citect的煤矿装车监控系统设计

 煤矿装车监控系统的稳定性、快速性直接关系到整个煤矿煤炭供销和输配调度,对整个煤矿企业的生产和效益起到至关重要的作用。本文提出了一种基于Citect组态软件为开发平台的选煤厂煤炭装车监控系统,介绍了煤炭装车系统硬件设备组成和软件功能,能够通过工业快速以太网通信方式实时监控系统的工艺参数和设备状态,保证了系统稳定安全运行,提高了生产效率。     

选煤厂装车系统高效化升级改造

选煤厂装车系统,作为矿井产品煤外运的关键部位,随着矿井产量的逐年提升,装车系统部分环节能力不足的问题日益凸显,为此,成庄矿洗选厂对装车系统进行高效化升级改造,不仅优化了装车系统,也满足成庄矿千万吨能力精品矿井的需要。     

油气火灾下椭圆形钢柱性能的试验研究

椭圆形空心钢构件是一种有效的钢构件。尽管其外形和结构效率均有很大吸引力,但还没有相关的耐火规范,这限制其在工程中的应用。故首次研究了椭圆形空心构件钢柱的耐火性能。在油气火灾下,对6根柱子进行试验,参数包括:3种荷载作用(αL=0.3,0.45,0.6)及2种长细比(λ=40.1,50.8)。给出了椭圆形空心钢柱的轴向位移和温度数据,并着重说明了椭圆形空心构件独特的局部及整体屈曲破坏模型。     

数据中心的环境设计与供电系统选型（1）

本文介绍了数据中心机房建设需要考虑的几个问题：可靠性分配,高可用性机房建设的要点,UPS的选型要点以及UPS系统容量选择的考虑,并以实例介绍了选择的计算方法。     

求解强异类集装箱装载问题的混合蚁群算法

针对强异类集装箱装载问题,设计了一种混合蚁群算法。算法中搜索空间分为货物摆放的优先序列和货物摆放的状态两部分;引入体积大的货物优先放入的启发式规则;将蚂蚁搜索得到的序列与历史最优序列进行交叉,取三者最优序列作为该蚂蚁的搜索路径;在更新信息素时,采取两种挥发系数更新信息素以避免信息素过快饱和,同时分析了算法的复杂度。通过三个强异类实例的测试,表明算法得到的装载方案有较高的空间利用率。     

Application of KF/MgO as a heterogeneous catalyst in the production of biodiesel from rapeseed oil

Biodiesel was synthesized from rapeseed oil by transesterification over Magnesium oxide loaded with KF. The catalytic activity strongly depends on the loading amount of KF and calcined temperature. We found that the reaction reached a 79.37% yield when the loading amount was at 35 wt% and calcined at 500 °C. The simply dried 30% KF/MgO at 80 °C was found to give equally good results from the catalyst calcined at 500 °C, avoiding the usual activation at high temperature. The catalysts were characterized by the Hammett indicator method, BET, TG/DTG, XRD, NMR, EDS, and FT-IR. According to the instrumental analysis, the activity in the transesterification probably belonged to coordinately unsaturated F⁻ and liberation of hydroxide during preparation. The effects of methanol/oil ratio and catalyst amounts on the conversion were also studied in this paper.     

Onsager coefficients for binary mixture diffusion in nanopores

This paper presents a critical appraisal of current estimation methods for the Onsager coefficients L₁₁, L₂₂, and L₁₂ for binary mixture diffusion inside nanopores using pure component diffusivity data inputs. The appraisal is based on extensive sets of molecular dynamics (MD) simulation data on L_ij for a variety of mixtures in zeolites (MFI, AFI, TON, FAU, CHA, DDR, MOR, and LTA), carbon nanotubes (CNTs: armchair and zig-zag configurations), titanosilicates (ETS-4), and metal-organic frameworks (IRMOF-1, CuBTC). The success of the L_ij predictions is crucially dependent on the estimates of the degree of correlations in molecular jumps for different guest-host combinations; these correlations are captured in Maxwell-Stefan approach by the exchange coefficients ?_ij. Three limiting scenarios for correlation effects have been distinguished; for each of these scenarios appropriate expressions for the L_ij are presented. For CNTs, correlation effects are dominant and the interaction factor, defined by , is close to unity. For cage-type zeolites such as LTA, CHA, and DDR with narrow windows separating cages, correlation effects are often, but not always, negligibly small and the assumption of uncoupled diffusion, i.e., α₁₂=0, is a reasonable approximation provided the occupancies are not too high. In other cases such as zeolites with one-dimensional channel structures (AFI, TON), intersecting channels (MFI), cage-type zeolite with large windows (FAU), ETS-4, CuBTC, and in IRMOF-1, it is essential to have a reliable estimation of the ?_ij; MD simulations underline the wide variety of factors that influence the ?_ij.We also highlight two situations where estimations of the L_ij fail completely; in both cases the failure is caused due to segregated adsorption. In adsorption of CO₂-bearing mixtures in LTA and DDR zeolites, CO₂ is preferentially lodged at the narrow window regions and this hinders the diffusion of partner molecules between cages. The second situation arises in MOR zeolite that has one-dimensional channels connected to side pockets. Some molecules such as methane, get preferentially lodged in the side pockets and do not freely participate in the molecular thoroughfare. Current phenomenological models do not cater for segregation effects on mixture diffusion.     

结晶器振动装置中长臂的瞬态有限元分析

以直弧形四连杆型结晶器振动装置中的长臂为研究对象,利用模型切分方法,完成长臂复杂模型的全六面体网格划分,根据结晶器振动周期内前后两个半周期内不同作用力,运用有限元中分步加载的方法完成了一个周期内的长臂瞬态动力学分析.计算结果表明:在周期性交变载荷作用下,长臂的最小和最大综合应力的变化趋势几乎相同.二者后半周期的变化没有前半周期明显,且都存在极值波峰情况.在临界变化点时,波动差最大,极易使长臂产生破坏,因而在设计时应采用对长臂弯折处进行导角设计和局部增加筋板等方法以提高长臂的抗疲劳能力.     

Effects of Loading Process and Contact Shape on Point Impact Elastohydrodynamics

The squeeze effect is an important subject in studies of elastohydrodynamic lubrication (EHL). By impact loading, the oil between point contact surfaces is entrapped at the central region or the peripheral region depending on the initial conditions. The effects of the loading process, surface roughness, and ellipticity ratio of contacts on the film thickness and pressure distributions are not fully understood yet. In the current study, those effects are elucidated through numerical analyses by specified initial impact gaps, which produce the central or the peripheral oil entrapments. The loading process, which can produce rather low pressure, has been proposed. Moreover, conditions, under which a microdimple is produced in the central circular bump are clarified.     

电子设备装车设计技术

本文简述了电子设备装车设计的重要性,以电子方舱为例具体介绍了电子设备装车设计技术的主要内容,并提出了解决电子设备装车设计中的抗冲震设计、通风散热设计及电磁兼容设计等关键技术的途径和方法。