ZigBee无线传感器网络在瓦斯监控系统中的应用

为了提高煤矿瓦斯监控系统的安全性和稳定性,采用符合ZigBee技术的芯片CC2430,设计了煤矿瓦斯监控系统.该系统采用典型的无线传感器网络结构,以基于分簇的能量控制路由算法,降低了网络系统的能耗,延长了网络使用寿命.分析表明,ZigBee技术在煤矿瓦斯监控系统中应用,可有效地减少煤矿安全事故的发生,降低井下人员的伤亡,保证系统传递信息的实时性和有效性.     

Zigbee网络应用在煤矿井下环境的技术优势

现代煤矿企业对于信息自动化的要求越来越高,很多技术集中的生产场所都要求实现无人化的智能管理。建设井下大范围环境监测监控和人员监测监控系统,可以减少下井人员数量,降低井下人员工作强度,并做到精确监控与有效管理。现有的井下监控系统对传感器以及设备信息的采集主要依靠硬接线,存在着布线工作量巨大而且复杂,维护困难的缺点。近年来无线通讯技术陆续用于部分井下系统,而针对井下生产设备监控和环境安全监控的无线监控系统基本处于试验阶段。ZigBee作为一种新兴的近距离、低复杂度、低功耗、低数据速率、低成本的无线网络技术,相对其他无线传输技术更适合煤矿井下环境。本文将从技术原理、传输速度、传输距离以及功耗等方面论证其优势。     

基于Zigbee的井下人员定位考勤系统的设计

本文基于ZigBee技术,设计了煤矿井下人员定位考勤系统,实时对井下人员进行定位、身份识别。实现了井下人员的考勤统计,并为监控井下的人员分布提供了依据,适用于煤矿井下的安全管理。     

煤矿井下Zigbee网络技术研究

文章开展了Zigbee技术在矿井井下应用时工作对象分析、产品性能选取的工程实践工作,力求在现有Zigbee产品以及通用的工业控制产品的基础上合理选择设备参数,满足井下监测系统要求.文章分析了矿井井下监控应用的需求,确定了井下ZigBee监控网络的构成方案;并分析了井下环境因素(如巷道的形状和走向、井下粉尘及湿气等)对ZigBee无线传输的影响以及监控数据量的需求,在此基础上确定了井下无线监控网络的主要技术参数以及节点设备构成.     

基于组态的煤矿安全监控系统的研究

我国矿井分布广阔、地质条件复杂,煤矿的安全生产与井下工作人员的人身安全息息相关。因此,煤矿事故的多发成了煤炭开采中的最大隐患经过研究发现对煤矿开采中的井下环境状况实时监控,可以有效地降低事故的发生率．本文采用组态软件作为上位机对煤矿生产过程中的可能诱发煤矿事故的几项致灾因素进行监测,通过实时刷新使得监测人员掌握井下的安全生产状况,最终达到降低煤矿开采的事故率、     

基于ZigBee技术的井下人员定位安全监测系统

采用德州仪器(TI)公司CC2431芯片,构建了基于ZigBee协议的井下人员定位及安全监控系统.网络由网络协调器、定位参考基站、人员终端组成,通过在井下建立线状和网状ZigBee无线网络,实现井下人员定位、环境监测和通信等功能.通过人员终端测定附近定位基站的信号强度,可以用监控系统上位机软件实时观测井下人员的活动,并进行数据采集和传输.通过对天线的近场效应进行补偿性修正,定位误差降低了约50%.模拟井下环境的性能测试结果表明,该系统可以达到0.25 m的测量分辨率,定位误差小于2 m,可以支持4 kbps的数据传输,满足井下人员定位和事故发生时的疏散调度要求.     

ZigBee技术在煤矿井下通信系统中的应用

ZigBee是一种成熟的无线通信技术。本文介绍ZigBee技术特点,协议模型及应用,并以该技术为基础,设计了一种应用于煤矿井下的无线通信系统。     

矿井下ZigBee的Mesh网络安全监控系统设计

针对煤矿井下安全监控的需求,通过方案和系统设计、NS仿真分析,开发了一种基于ZigBee技术与Mesh网络相结合的安全监控系统。该系统通过安装在终端节点上的传感器采集井下数据,将采集到的数据通过Mesh网络传输到井上监控中心,实现对井下环境数据的实时监控。该系统具有可靠性高、网络覆盖范围大、移动性好的特点。对煤矿井下安全监控及安全事故的预防具有指导意义。     

井下瓦斯浓度监测机器人控制系统的设计

针对煤矿瓦斯爆炸事故问题,本文将ZigBee无线传感技术与履带式机器人探测技术相结合,研究了一种具有独立越障、避障能力的井下瓦斯浓度监测机器人。机器人以S3C2440为核心控制单元,结合CC2430射频芯片,在嵌入式系统Linux下控制机器人,快速准确地探测井下瓦斯浓度并及时想地上监控中心传送数据,一旦监测到井下有瓦斯异常情况,可及时发出警报,能够较好的完成井下瓦斯爆炸事故的预测和报警工作,对保障工人安全具有重要的现实意义。     

基于ZigBee技术的矿井安全监控系统

针对煤矿复杂的工作环境及安全生产的要求,提出一种基于ZigBee技术的矿井安全监控系统.首先介绍了ZigBee技术的特点,重点对井下数据采集子系统进行了设计,其中主要包括井下人员携带的ZigBee终端移动节点、ZigBee路由器以及ZigBee协调器的设计,并通过CAN总线将采集的数据传送到地面监控中心,最后给出了井上...     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.