煤自燃过程气态产物产生机理

为了能够更加有效地利用气态产物预报煤的自燃过程,需要对煤自燃过程产生气体的机理进行深入研究.利用实验模拟出煤自燃气态产物的产生过程,得出其规律是:不同指标气体开始出现的温度不一样,同一指标气体在不同煤体中出现的温度不同.对煤低温氧化过程微观结构、自由基浓度与煤体温度之间的变化规律的分析,并以煤自燃自由基和逐步自活化反应为理论基础,提出了新的煤自燃过程气态产物产生机理,即煤中不同活性结构在不同温度下被活化发生氧化反应,在发生氧化反应时该类结构发生断裂形成自由基.不同自由基之间,自由基与氧之间相互发生反应,形成不同的指标气体从煤体中释放出来.图3,表4,参12.     

煤自燃过程中极限参数的研究

煤自燃过程是煤氧化产热和环境散热之间平衡关系的变化过程，通过对煤自燃过程的热平衡关系进行分析，导出了煤体氧化蓄热升温的必要条件的数学表达式，在此基础上，研究得出了上限漏风强度、上限煤体粒度、下限氧含量和下限煤体厚度4个煤自燃过程的重要极限参数，研究结果表明，任何一种煤在氧化蓄热过程中，只有同时满足煤体的漏风强度小于该煤体的下限漏风强度，煤体粒度小于其上限煤体粒度，煤体中的氧含量大于其下限氧含量，以及煤体厚度大于其上限煤体厚度，才有可能引起自燃，这一研究结果为进一步完善煤自燃理论以及研究新型自燃防治技术提供了必要的理论基础。     

原始赋存水分对煤自燃过程的影响及作用机制研究

通过干燥处理褐煤原煤,制备出不同含水量的褐煤煤样,用程序升温氧化装置实现煤自燃过程模拟,利用原位傅里叶红外变换光谱仪测定煤自燃过程中氧化煤样活性官能团的变化,同时利用氮吸附仪和热分析仪表征煤自燃过程中微观比表面积和质量的变化规律,探讨原始赋存水分对煤自燃过程影响作用机制。原始赋存水分对煤自燃过程的作用机制主要表现在4个阶段:在缓慢氧化阶段,外来水分对煤氧化主要起到了物理抑制作用,外来水分的持续挥发引起煤体质量与羟基和羧酸组分含量的降低;在加速氧化阶段,煤中水分直接参与反应,对煤氧化起到化学促进作用,羧基类化合物含量开始显著增长,原始赋存水分对煤氧化的抑制作用逐渐减小;在快速氧化阶段,煤体原始赋存水分基本脱除,内在水分脱除过程中煤体孔隙结构持续坍塌碎裂,产生新活性点位,对煤氧化反应过程表现出延迟促进效应,内在水分主要作用于中间络合物生成和分解以及气体的释放;当煤体温度达到180℃后,原始赋存水分参与和影响煤氧化反应过程效果微弱,煤体自燃特征趋于一致。     

煤自燃过程的动态数学模型及数值分析

通过煤自然发火实验和松散煤体粒度与氧化自燃性关系实验，推算出煤自燃过程中一些特性参数的计算公式．根据多孔介质流体力学、传质和传热学理论，建立了松散煤体漏风流流场、氧浓度场和温度场的数学模型．通过实验和理论分析，建立了松散煤体自然发火的三维动态数学模型，分析了模型边界条件的确定方法，并采用有限差分法对二维模型进行了数值求解．     

三相泡沫阻化特性实验研究

提出了三相泡沫防治煤炭自燃的新技术．利用煤自燃特性实验系统测试研究了三相泡沫处理后煤样的氧化升温速率和CO的释放速率，包括煤样煤质、三相泡沫浓度、浆液农度和颗粒粒度等因素的影响．研究结果表明三相泡沫对煤体的阻化效果显著。能有效地减缓煤的氧化放热速率，抑制煤温度的升高；同时也极大地抑制了CO的释放量．图6，表2。参8．     

程序升温条件下煤炭自燃特性

通过程序升温实验研究了煤炭的自燃特性，测定了不同粒度煤样在不同温度下产生CO，CO2等气体的浓度，讨论了指标气体的选择，分析了CO，CO2等气体浓度随温度的变化规律，得到了耗氧速度与煤温及煤温及煤体粒度的关系，结果表明，煤体粒度越小，温度越高，则煤氧复合的强度越大，本实验的研究结果对煤矿火灾的防治具有指导作用。     

灰分对煤自燃特性影响的实验研究

为了研究灰分对煤自燃能力的影响作用,利用绝热氧化实验装置对不同灰分含量煤样进行升温氧化实验,采用R_(70)、T_(CPT)、B3种指标表征灰分含量对煤样自发氧化过程的影响。结果表明:1)灰分含量越大,煤样低温氧化阶段温升速率越小,温升加速点温度越高,煤样的自发氧化过程越慢,煤越不易自燃;灰分含量大于40%后,煤自燃倾向性快速减弱。温升加速点是反应微观信息的零活化能温度的宏观累计结果,具有直观且滞后的特点。灰分越大,滞后越明显,温差越大。2)R_(70)、T_(CPT)、B3种指标与灰分关系表现为二次函数。R_(70)和T_(CPT)两种指标显示灰分越大,自燃倾向性越弱,与实践经验相符。受水分权重影响,B指标显示煤样在灰分小于40%时,灰分越大,煤样自燃倾向性越强,这与实践经验相悖。因此,B在判定灰分对煤样自燃倾向性的影响时具有一定的局限性。     

褐煤自然发火特性实验及数值模拟

 为研究褐煤的自然发火特性,采用恒温加热法,对不同尺寸的立方体网状容器内的煤样进行实验,得到煤样的升温曲线和临界自燃点温度。根据实验条件,应用Fluent软件建立煤样升温过程的温度场、空气渗流场和氧气浓度场三场耦合模型。实验与模拟结果表明：煤体体积越大,临界自燃温度越低;当环境温度高于临界自燃温度值,煤体能够自燃,反之煤体不能自燃;煤体升温过程中的温度场、空气渗流场和氧气浓度场是随着时间变化并且相互影响的。     

沿空侧煤柱耗氧-升温的三维数值模拟

为研究综放工作面沿空侧破碎煤柱耗氧和释热对自燃发展过程的影响,构建反映煤柱内部氧化升温关系的三维数值模型,利用FLUENT软件对其流场分布进行数值解算.研究结果表明:巷道内空气向顶煤和煤柱渗流—扩散效应明显,渗流影响范围从进风口向出口递减,破碎煤体具有比煤层更好的氧化条件.高温区在空间上位于进风处附近,煤体内部升温速率不但随着时间的增加呈现加速,整体温度分布也有上移的趋势.在煤质一定的情况下,巷道风速会使自燃更加恶化.该研究结论可以在现场防火工作中,事先对煤体破碎程度、释热能力、巷道风量和氧化时间进行综合评估,缩小火源探测范围,提高防火工程效率.     

煤分子中活性基团氧化与煤的自燃机制探讨

本文从导致煤体增温条件和致发起火燃烧两个方面探讨了煤炭自燃的机制,指出了煤分子中侧链、桥键等活性基团在氧化反应中产生自由基,引起链式反应,形成生热条件,而具有很大內表面且易产生自由基的丝炭是煤炭自燃的导火索。     

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.     

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.     

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

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

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the