浅析影响挥发分测定的几个因素及措施

从煤样粒度、加热温度和时间、坩埚和坩埚架、样品质量等因素出发，分析了影响挥发分测定的因素并提出了相应的措施。     

煤低温氧化动力学参数与粒度关系实验研究

探讨煤样粒度与表征煤氧化速度的活化能、指前因子的关系,了解粒度对煤的氧化反应速率等自然参数的影响,通过不同粒度东滩煤样的程序升温实验,测定了其不同温度下在空气中的耗氧速度。利用回归分析计算出反应的指前因子及活化能,并进行了分析。研究发现,随粒度降低,煤样氧化的活化能和指前因子均增加,并且在3mm处出现了突跃现象。说明煤的自燃性取决于粒度小于3mm颗粒的比例,而不是其平均粒度。     

煤升温氧化过程特征的热重分析

用热重方式进行了煤在常规条件下的热重实验,分别用TG/DTG曲线描述了煤燃烧的整个过程,分析了煤升温氧化过程的特征参数,得到了各种煤的着火温度等特征温度.结果表明,煤样的特征温度与挥发分存在一定的规律性,特征温度下的失重值受挥发分的影响,着火温度随挥发分增加呈线性下降.     

双鸭山集贤煤矿煤样自燃性程序升温实验研究

采用程序升温实验装置，研究双鸭山集贤矿不同粒度煤样在不同温度条件下与氧反应的特性。通过实验分析，得出双鸭山集贤矿煤自燃预测预报的主要指标气体为CO。通过计算得出不同粒度煤样的耗氧速度和CO，CO2，CH4等气体的产生速率，以及这些特性参数随煤温和粒度的变化规律。进而分析得出该矿煤样自燃的临界温度为65～75℃。为双鸭山集贤矿煤自然火灾的预测预报提供依据。     

污泥及其与煤混合物的热解特性和灰熔融特性

采用热重分析法对造纸污泥、市政污泥及其与煤的混合物的热解特性进行了系统研究.揭示了污泥、煤及其两者混合物热解特性的异同,研究了升温速率、掺混比等因素对混合试样热解特性的影响,提出了挥发分综合释放特性指数.研究表明:造纸污泥的挥发分析出特性与烟煤相当,而市政污泥的挥发分析出特性远优于造纸污泥和烟煤;在污泥与煤混合物的热解过程中,2种组分之间的相互作用可以忽略不计.随着升温速率的增加,污泥与煤混合物的挥发分初析温度提高,挥发分最高析出速率和平均析出速率升高.但升温速率对挥发分析出总量没有明显影响.测定了煤灰和污泥灰在不同混合比例下的熔融特征温度,测试结果表明,随着污泥灰比例的增大,混合试样的灰熔点逐渐下降,但由于存在低温共熔现象,不按线性规律变化.     

利用X射线光电子能谱确定煤及其残焦中硫的形态

利用X射线光电子能谱(XPS)技术分析了宜宾煤及其释放出挥发分后残焦中硫的形态,研究了煤中的硫在挥发分释放过程中的迁移规律.结果表明:XPS能够鉴别出宜宾煤中的硫;宜宾煤的S2p图谱有2个需要解叠的峰,分别位于163～164eV和169～171eV之间,这主要是由煤中的硫化铁和硫酸盐引起的;宜宾煤中含有硫砜,但不含亚砜.残焦的分析结果表明,在900℃加热条件下,宜宾煤在释放挥发分的同时,其中的部分燃料硫能够转化为硫酸盐和亚硫酸盐并被固定在残焦之中.在煤的挥发分释放过程中,也有部分燃料硫与挥发分一起释放出来,其份额与加热温度有关,随温度的升高而增加.     

松散煤低温耗氧速率的多因素作用特征及模型

为给采空区煤自然发火的实际探测及数值分析提供理论支持,研究氧体积分数(φi)、粒度(D)和温度(T)复合作用条件下的松散煤低温氧化的耗氧速率(v0)模型。设计松散煤在氧体积分数相同、粒度不同和粒度相同、氧体积分数不同2种方式下煤的程序升温实验,应用气相色谱仪分析特定温度下的出口气体氧体积分数并对松散煤的耗氧速率进行计算,比较不同氧体积分数、粒度条件下煤样在不同温度点的耗氧速率,得出单一变量条件下的v0-φi,v0-D和v0-T曲线。研究结果表明:耗氧速率与煤样温度基本呈指数关系,与氧体积分数呈对数关系,与松散煤样粒径呈负指数关系;在低温条件下,温度、粒径和氧体积分数3个因素对松散煤耗氧速率的作用相对独立。最后,在实验分析的基础上建立以耗氧速率为因变量,温度、氧体积分数、粒度为自变量的松散煤低温耗氧速率复合作用模型。     

煤的挥发分准确测定影响因素浅析

挥发分是煤的工业分析中最重要的一个指标,也是最难测准的一个项目.影响挥发分测定的因素很多,主要有加热温度和时间;坩埚材质、大小、厚薄、严密性与坩埚架大小;试样的质量和粒度以及水分测定的准确度和实验操作是否规范等.对各影响因素进行了分析与讨论.     

氧化钙对褐煤和无烟煤热解特性影响

为研究CaO对褐煤和无烟煤热解特性影响,采用实验室小型固定床反应器对锡林郭勒褐煤(X)和宁夏石嘴山无烟煤(SH),进行热解实验,研究了CaO对热解三相产物分布规律影响。实验结果表明:在500~600℃时,添加2%CaO后褐煤热解生成CO_2的产率小于未添加CaO煤样热解生成CO_2的产率,添加CaO与否对其他3种气体H_2,CH_4,CO产率影响不大;与未加入CaO的褐煤煤样相比,加入CaO的褐煤煤样在相应温度下热解气相产物产率小幅度降低,且随着热解温度的升高,加入CaO的褐煤煤样气相产物产率增加速率大于未加入CaO的褐煤煤样。褐煤脱挥发分主要在600℃之前的热解阶段,而对于无烟煤来说,CaO在中温热解阶段对挥发分的脱除具有促进作用。对于褐煤半焦来说,加入2%CaO一直作为灰分存在半焦中,且随着热解温度的升高,褐煤半焦在高温时反应活性较高,发生热缩聚反应,导致半焦中有机质含量降低,以上2种原因直接导致褐煤半焦灰分升高;对于无烟煤来说,灰分增加主要是由于CaO的加入。     

CO_2对煤低温氧化反应过程的影响实验研究

为了深入研究CO2对煤低温氧化反应的影响,利用程序升温油浴实验装置,研究在不同CO2浓度下煤样的自燃特性。采集南屯矿煤样,破碎并筛分出混合平均粒径为4.18 mm的煤样,向试验管煤样中通入不同配比的混合气体,实验控制升温速度为0.3℃/min,供气量为190 mL/min.测定在6种不同浓度CO2气氛下的煤样低温氧化特性,实验结果表明:CO2浓度越高,煤样耗氧速率越小,CO产生率降低。在起始阶耗氧速率相差不大,煤氧复合作用以物理吸附和化学吸附为主,后期阶段以化学反应为主,变化明显。相比于空气气氛下,CO2气氛下煤样活化能有所提高,在40~100℃的温度范围内煤氧作用的活化能值由17.85 kJ/mol升高至22.71 kJ/mol,氧化反应速率降低,表明CO2的加入降低了煤的氧化反应速率,抑制了煤的氧化反应。     

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.     

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.     

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.     

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.     

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.     

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.     

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