裂解气相色谱质谱法研究Lyocell纤维裂解作用

加热裂解Lyocell纤维,采用气相色谱质谱联用仪研究裂解过程.750℃时,鉴定了其中59种裂解产物,主要的裂解产物为二氧化碳、醛、酮、酸和酯类、呋喃类杂环化合物和糖类化合物等.1,6-脱水-β-D-吡喃葡萄糖(左旋葡聚糖)是Lyocell纤维的重要裂解产物.Lyocell纤维裂解过程中,发生侧基消去水反应,转糖苷作用引起链剪切作用,逆醛醇缩合反应的链剪切作用.经过分子重排,次级反应等形成了各种裂解产物.     

天然甲壳素热裂解制备精细化学品的研究

为了充分利用甲壳素这种丰富的天然资源,将甲壳素进行了热解,用热重量分析仪和示差扫描热量计来观测此分解反应,所得的挥发产物用红外光谱进行即时表征.用气相色谱-质谱(GC-MS)对这些挥发性物质进行进一步的鉴定.可以确认在挥发性化合物产品中,有大量的呋喃和吡咯类物质,其中乙酰胺是最主要的成分,其总量超过了其他挥发性化合物的总和.因此,甲壳素具有大批量制备精细化学品如乙酰胺,呋喃和吡咯的潜在价值.推测了甲壳素热解生成挥发性产物的反应机理.在高温下,乙酰胺的生成是由于侧链的断开,裂解以及产品挥发导致的.     

高温下催化热裂解甲壳素制备双环芳烃

甲壳素是仅次于纤维素的第二大生物质资源,开发甲壳素的利用途径对生物质资源的发展和环境保护都具有重要的意义。通过自制催化剂固定床热解器在高温下进行催化热解甲壳素制备双环芳烃的研究。工作中尝试了温度和催化剂进行热解产物影响,选择了ZSM-5,HZSM-5,MCM-41,β-分子筛和NaY分子筛五种分子筛催化剂进行对比实验。结果发现在700℃,N_2流速3L/h下ZSM-5做催化剂进行甲壳素热裂解获得最好的有机化合物质量产率24. 3%。通过GC/MS对产物的分析,产物中双环芳烃萘和甲基萘的选择性达到了65. 0%、13. 3%。其他催化剂在获得芳烃化合物上有着不同的选择性,通过催化剂的选择催化热裂解甲壳素制备不同的化学品,扩展了甲壳素的应用范围和芳烃的来源途径。     

裂解气相色谱质谱法研究废旧ABS塑料的热降解行为

采用裂解气相色谱质谱联用技术对ABS塑料的热降解行为进行了研究.在氦气氛围中,500℃下对ABS进行热裂解,通过色谱质谱联用仪对裂解产物进行了定性分析,共鉴定出苯乙烯、甲苯和4-苯基丁腈等31种裂解产物.根据裂解产物信息和有机物热裂解反应的原理对ABS的热裂解反应机理作了探讨.ABS塑料的热降解过程是典型的自由基历程,解释了裂解产物中芳香烃类化合物、脂肪烃类化合物、腈类化合物和含溴酚类化合物的生成机理.ABS的高温降解过程不是三种结构单元降解过程的简单累加,三种结构单元在其降解过程中相互明显影响,最终导致裂解产物在结构和类别上的多样性.废旧塑料ABS热裂解过程会产生多种有害污染物,因此,选择合适的裂解工艺条件,既可得到更多有用的裂解产物,又可减少对环境的污染.     

裂解气相色谱-质谱法研究聚醚砜的热裂解机理

采用裂解气相色谱-质谱联用仪(PyGC-MS)分析了聚醚砜(PES)在温度500~700℃内热裂解形成的产物种类及其相对含量.结果发现:500℃下PES热裂解形成的主要产物是苯酚,550℃时裂解才产生SO_2;随着裂解温度的升高,裂解产物的种类越来越多,SO_2逐渐成为主要的裂解产物.最后根据不同温度下形成的裂解产物的种类及其相对含量推测了PES产生热裂解的机理.     

油茶籽快速热裂解及产物分析

采用居里点热裂解仪-气相色谱-质谱(CP-GC-MS)联用分析技术,分别对油茶籽仁和种壳在358～590 ℃条件下进行快速裂解,并对产物组分进行了分析。结果表明,随着温度的增加,热裂解产物中的组分种类逐渐增加。籽仁热裂解产物主要为脂肪酸,此外还包括糠醛、β-香树脂醇和维生素E等附加值比较高的物质; 种壳的热裂解产物中,脂肪酸的含量占5%左右,主要的产物还包括苯酚类化合物,在产物中还检测到糠醛、香草醛和丁子香酚等附加值比较高的化合物。分析认为,油茶种壳的热裂解产物包含多种工业、医药以及食品行业所需求的原料,同时,产物中的长碳链烯烃类物质可作为生物质能源进行利用。     

生物油催化裂解精制机理

采用乙酸为模型化合物,在裂解温度500℃,质量空速为5.0h-1,不同水含量条件下进行了催化裂解精制实验,并采用GC-MS分析了催化裂解液体产物.乙酸经过HZSM-5分子筛催化剂催化裂解后,产物中含有苯、萘、茚及其衍生物.根据乙酸催化裂解产物,推测了乙酸催化裂解精制反应途径,说明生物油催化裂解精制反应过程主要发生脱氧和芳烃化反应.     

精馏法催化大豆油裂解制备可再生燃料油

采用自组装的裂解精炼装置,以大豆油为原料考察了精馏反应条件对裂解产物性能的影响。结果表明,最佳反应条件为：精馏柱温度范围320~350 ℃,裂解反应釜温度480~500 ℃,大豆油滴加速度为35 g/h。通过红外光谱（FTIR）、气质联用（GC MS）和凝胶色谱（SEC）对裂解产物的分析表明,产物具有较低的平均分子质量,主要成分为烷烃、烯烃、醛、羧酸等。从化学组成及燃料性能来看,裂解产物的性质与石化柴油相近,裂解所得产物密度825 kg/m3,黏度40 mm2/s,热值42 MJ/kg,冷凝点-9 ℃,冷滤点-4 ℃,具有较好燃料性能。     

氧化钙条件下焦油主要组分的催化裂解

为降低煤气化时焦油产率、提高煤气产率，利用固定床反应器研究了焦油的两种主要组分苯和甲苯在氧化钙条件下的裂解反应特性，探讨了氧化钙的催化机理。实验结果表明，与石英砂条件下相比，氧化钙在苯和甲苯裂解反应中具有催化作用，改变了反应路径，使苯和甲苯裂解活化能分别下降２８．６６％，４７．８７％，频率因子分别下降３，６个数量级；相同转化率所需温度分别下降约１５０℃，１００℃；碳析出量降低，气态裂解产物总产率提高。     

核壳丙烯酸酯类树脂热裂解-气相色谱/质谱研究

采用热裂解-气相色谱/质谱法(PY-GC/MS)对核壳丙烯酸类树脂(ACR)进行分析.ACR样品在500℃条件下进行热裂解,裂解产物通过BPX5石英毛细管柱分离和质谱鉴定,获得了ACR在热裂解条件下的特征化合物.并通过对已知均聚物同条件分析的验证,找到了ACR各个热裂解产物的来由,从而确定了组成ACR共聚物的单体.对ACR丙酮不溶物的分析,初步探索了ACR粒子的内部组成结构.     

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