基于小白鼠实验的新型膨胀阻燃低密度聚乙烯复合材料烟气毒性研究（英文）

利用小白鼠试验来研究新型阻燃低密度聚乙烯(LDPE)复合材料的烟气毒性,探寻材料烟气毒性最大不至死浓度,根据相关标准判断材料毒性所属级别,并比较研究不同燃烧状况下阻燃LDPE复合材料产烟毒性.从烟气毒性实验可知,有焰燃烧比无焰燃烧具有较小的烟气毒性.同时利用火灾性能指数和火灾发展指数对阻燃LDPE复合材料的火灾安全性进行评价.研究结果有助于优化设计环境友好、综合性能优良的阻燃低密度聚乙烯复合材料.     

五合板的燃烧特性及其动态和静态生烟特性

利用热重分析仪(TGA)、差示扫描量热仪(DSC)、锥形量热仪(Cone)和塑料烟密度仪研究五合板的燃烧特性和生烟特性,并对燃烧特性与生烟特性的相关性进行分析。研究结果表明:五合板的热解过程可分为3个阶段,即干燥和粗挥发阶段、热解阶段和炭化阶段,其中热解过程为先吸热后放热的过程。五合板的动态烟释放(比消光面积、生烟速率和总生烟量)及静态烟释放(比光密度和质量光密度)与其燃烧过程有关且随着辐射功率的增加而增大,其中锥形量热仪实验中五合板的峰值生烟速率、总生烟量与峰值热释放速率之间存在较好的线性关系。五合板的静态生烟特性还受火焰条件的影响,其中相同辐射功率下有焰燃烧的比光密度和质量烟密度低于无焰燃烧条件下的,但质量损失却明显高于无焰条件下的。     

烟气再循环对蓄热式平焰燃气炉内燃烧特性的影响

平焰燃烧与蓄热式燃烧技术一起使用时火焰温度较高,热力型氮氧化物生成量较大。采用烟气再循环技术是降低蓄热式燃烧过程中热力型氮氧化物的生成量的有效途径之一。文中采用蓄热式平焰燃气试验炉、综合烟气分析仪、热电偶等设备,对比研究了采用烟气再循环和不采用烟气再循环2种工况下平展流火焰特性、炉顶温度分布和烟气中NO生成特性。结果表明:采用烟气再循环使平展流火焰面暗区变小,燃烧区域扩大,火焰面温度分布更加均匀,烟气中NO浓度明显降低,火焰面峰值温度降低9℃,谷值温度升高37℃,NO浓度最大降幅为20%。     

粗煤气基本燃烧特性的实验研究

在实验室条件下对粗煤气在不同过量空气系数和不同燃料配比条件下的燃烧特性进行了研究。通过测量燃烧室内的温度分布及烟气成分含量,分析了过量空气系数和燃料配比对粗煤气燃烧特性的影响。实验结果表明,一定工况下的混合气完全燃烧时对应有一个最佳过量空气系数;不同燃烧配比工况时混合气表现的整体燃烧特性不同,提高氢气含量可改善气体的燃烧特性,这可为多联产全程的粗煤气实际利用提供指导与依据。     

典型阻燃材料火灾毒性烟气释放规律研究进展

对可燃材料进行阻燃处理,可以在一定程度上提高材料抵抗被引燃和火焰蔓延的能力,降低热释放速率和总热释放量,减小材料在火灾条件下的热危害。但是对材料进行阻燃处理并不是万全之策,在较高的热辐射或环境温度下,阻燃材料仍然能够发生燃烧,同时由于阻燃剂的填加,会引入一些毒性元素,加之阻燃剂的燃烧抑制作用和燃烧时环境氧浓度相对较低,使材料燃烧不完全,因此阻燃材料燃烧时毒性气体的产量可能比非阻燃材料高,给火灾中未能及时疏散的人员带来更大的生命危险。综合分析了常见材料的阻燃技术及应用领域,综述了阻燃材料火灾烟气毒性的相关研究,并在此基础上提出了典型阻燃材料火灾毒性烟气释放规律研究方面存在的有待进一步研究的问题和可行的方法。以期为科学、全面的评价材料的火灾危险性提供研究参考。     

通风量对火灾烟气中CO2和CO释放的影响

该文利用文献中评价材料毒性的原始实验数据,从烟气毒性物质释放的角度,分析了火灾烟气中CO2和CO的释放特性,并着重分析了通风量的影响机理.研究发现CO2和CO的释放受燃烧模式的影响.在通风控制模式下,木材的扩散燃烧按照挥发分和固定碳燃烧分阶段进行,并受扩散供氧和燃烧耗氧之间制约关系的影响,其烟气成分的释放也具有上述特点.另外,数据分析表明,燃烧存在临界通风量和着火延迟.通风量具有强化燃烧和稀释、掺冷烟气的双重作用.     

基于复杂热解和化学反应修正的电缆燃烧模拟研究

电缆燃烧仿真模拟对电缆燃烧特性可进行有效研究,从而获取电缆火灾蔓延、烟气发展等规律,对于电缆火灾防护具有重要意义.针对多层结构电力电缆难以准确燃烧模拟的问题,本文根据实际燃烧原理建立了固相热解与气相反应研究模型.首先,对不同的固相热解设置进行了模拟,分析了热解质量损失率的差异,模拟表明复杂热解更能反映真实电缆热解的变化...     

无焰氧化气流床气化实验炉设计与气化特性研究

根据煤粉无焰氧化燃烧的条件与技术要求,设计定制了一圆形横截面的煤粉气流床气化实验炉.并在炉膛上对冲布置了三层煤粉喷嘴、切向布置了三层空气喷嘴.在实验炉上分别进行了冷态流场实验与典型工况下的煤粉无焰氧化气化特性实验.研究结果表明,在三层煤粉喷嘴投入运行且氧/碳原子比为1.0左右时,气化炉的气化特性最佳,有效气组分（CO＋H2）浓度、合成气热值和冷煤气效率均达最大值,分别为30.3%,4 477kJ/Nm3和75.29%.     

氨燃烧污染物特性的实验研究及动力学分析

在旋风无焰燃烧炉中研究了空气预热温度、热负荷及当量比对氨气无焰燃烧污染物生成特性的影响,通过Chemkin分析了NO_x生成的动力学原因．实验和模拟结果表明：无焰燃烧可以显著拓宽氨气的可燃极限,稳定的无焰燃烧可以在1 300 K以上实现．贫燃条件下,当量比?=0.6～0.8时NO_x排放量达峰值,H₂ 排放和氨逃逸几乎为零．热负荷升高使远贫燃极限点的炉温升至1 400 K以上,NH+O₂==NO+OH和HNO+OH==NO+H₂O这两种主要NO生成路径的反应速率明显提高,促使远贫燃工况点的NO排放量迅速增加,NO_x排放峰值向远贫燃工况偏移．在富燃条件下,NO和N2O的排放量几乎为零,H₂ 排放和氨逃逸迅速增加．在微贫燃工况下(?=0.96～0.97),最终实现了最低体积分数为5.6×10^-5的NO_x排放和3.7×10^-5的氨逃逸．     

城市污水污泥热解和燃烧的实验研究

利用热重分析仪对城市污水污泥分别在氮气和空气气氛下进行热解和燃烧特性实验研究,分析了污泥在不同气氛条件下热解及燃烧的反应机理,并采用微分法确定了燃烧反应的机理方程,求出污水污泥反应动力学参数活化能和频率因子.实验研究的结果为污泥流化床焚烧炉的设计计算提供理论依据.     

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.     

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