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1.
利用热重法研究了半芳香尼龙聚联苯醚二甲酰十二碳二胺(PA12-O)在N2气氛中以不同速率β升温时的热降解过程及热降解动力学.结果表明,PA12-O的热降解是一步反应,随着β的增大,降解温度呈指数关系升高.其起始平衡降解温度为439.4℃,终止时的平衡降解温度为468.33℃,最大降解速率时的平衡降解温度为459.17℃.为确定PA12-O的热降解机理,比较了用Kissinger、 Flynn-Wall-Ozawa和 Coats-Redfern方法求得的PA12-O的热降解表观活化能,证明PA12-O的热降解机理为减速类型.  相似文献   

2.
TGA/SDTA、DSC和Py-GC-MS分析叶醇糖苷热降解性质   总被引:1,自引:0,他引:1  
为了开发热稳定型香原料,采用热重分析/同步差热分析法(TGA/SDTA)、差示扫描量热法(DSC)和在线热裂解气相色谱质谱法(Py—GC—MS)对叶醇糖苷的热降解行为及产物进行了研究.TG—DTC曲线显示主要失重区间在230—370℃,峰值为339.8℃,总失重96.9%;DTA显示在290—360℃有一个吸热峰,峰值为339.8℃;DSC显示230~340℃为吸热区间,峰值为301.3℃;Py—GC—MS测定了在200,350,500,650℃各温度下叶醇糖苷裂解的主要产物.在200℃,裂解量很少,350℃时则产生大量的叶醇和少量副产物,随着温度的升高,500℃和650℃时产生的副产物增加,使叶醇糖苷释放叶醇的最佳温度是350℃;热裂解的特征产物是叶醇,说明主要的裂解反应是氧糖苷键的断裂.  相似文献   

3.
采用高温固相合成法制备Cu Mn2O4/Ni Mn2O4热敏催化剂,通过XRD、TEM、TGA、UV-vis和SEM等手段对样品进行了表征,研究了近常温热催化降解亚甲基蓝有机污染物。结果表明:亚甲基蓝底物质量浓度分别为30、40和50 mg/L时,随着温度从30、35到40℃的升高,去除率分别达到68.35%、79.64%和88.89%;在完全遮光、40℃、亚甲基蓝底物质量浓度为30 mg/L和热敏催化剂用量45 mg的条件下,经过48 h热催化降解过程,最佳降解率达到最优。此外,利用GC-MS对降解产物进行了分析,发现降解的主要产物为二氯甲烷和甲苯,由此证明亚甲基蓝确实发生了降解反应,且其降解程度也比较彻底。综上所述,近常温热催化降解途径将为未来工业废水处理提供潜在解决方案。  相似文献   

4.
SBS-g-MMA的合成及热降解动力学分析   总被引:3,自引:1,他引:2  
将甲基丙烯酸甲酯(MMA)与SBS接枝共聚制得SBS-g-MMA接枝共聚物.利用热分析法研究了该共聚物在升温速率为10 K·min-1的N2气、O2气气氛中的热降解过程与热降解动力学.确定了SBS-g-MMA在N2气气氛下的热降解过程分2步完成,第1步热降解温度为530~720 K,第2步热降解温度为 720~830 K;在O2气气氛下的热降解过程分3步完成,第1步热降解温度为477~597 K,第2步热降解温度为597~714 K,第3步热降解温度为714~774 K.在N2气气氛下的热降解过程的平均活化能Ea=376.27 kJ·mol-1,微分机理函数f(α)=(1-α)[-ln(1-α)]-2/3,指前因子lnA=73.029,积分机理函数g(α)=[-ln(1-α)]3,指前因子lnA=64.220;在O2气气氛下的热降解过程较为复杂,实验结果不明确.  相似文献   

5.
采用在线热裂解-气质联用(Py-GC-MS)技术对废旧硅橡胶复合绝缘子在不同温度下(300 ℃,400 ℃,500 ℃,600 ℃)的热降解行为进行了研究,并通过质谱中裂解产物的碎片离子信息对其裂解机理进行探究。结果表明:硅橡胶裂解产物为一系列二甲基硅氧烷环体及少量的链状硅氧烷,主要环体为六甲基环三硅氧烷(D3)、八甲基环四硅氧烷(D4)及环五硅氧烷直至环九硅氧烷;较高的裂解温度下,大环基本裂解完全,仅剩小环裂解产物。因此用热裂解处理废旧硅橡胶时,温度需要达到500 ℃及以上才会有较好的效果。  相似文献   

6.
为了降低聚酰胺的熔融温度,运用分子设计的方法,采用芳香族和脂肪族两类二元胺共缩聚,成功地合成了三个系列的热致液晶聚酰胺。这些共聚酰胺具有300℃以下的熔融温度100℃以上液晶温度范围和稳定的液晶相。通过偏光显微镜、X光衍射分析和DSC分析等手段,确认上述热致共聚酰胺液晶为向列型液晶。  相似文献   

7.
采用热重-傅里叶红外光谱联用(TG-FTIR)技术对桉木碱性过氧化氢法(APMP)制浆废液固形物(ASLS)热裂解过程中主要挥发性产物的释放规律进行了研究,结合高温静态水平管式炉快速热解及气相色谱(GC)、气相色谱-质谱联用技术(GC-MS)对挥发分组成进行了确认.TG-FTIR结果表明,ASLS热解过程分为3个阶段,热解温度区间分别为200 ~371℃、371 ~530℃和745 ~986℃,第1热解阶段的主要产物为CO2,占总产物的90%以上,第2热解阶段的主要产物为CO2、CH4、醛酮类化合物和酚醇类化合物,第3热解阶段的主要产物为CO.GC分析结果显示,H2、CH4、CO、CO2、C2 H4和C2H6是热解的主要不可冷凝产物.GC-MS分析结果表明:醛酮类和酚类化合物是ASLS热解过程中的主要可冷凝产物,这与TG-FTIR结果相一致;醛酮类化合物在600℃左右达到最大产率41.43%.  相似文献   

8.
高性能纤维的热降解行为及动力学参数比较   总被引:1,自引:0,他引:1  
利用TG方法研究3种高性能纤维材料(Zylon(PBO),Kevlar129和Kermel纤维)在氮气和空气中的热降解过程和动力学参数.实验发现,样品在氮气中的降解特征温度比空气中的高30℃左右,且PBO纤维热降解的特征温度最高,所建立的综合温度指标可有效评价这一特性.同时,利用Freeman-Carroll法研究样品的热降解动力学参数,计算比较3种材料的反应活化能及反应级数,结果与特征温度分析基本一致.  相似文献   

9.
《河南科学》2016,(8):1245-1251
戊二酸酐和薄荷醇在4-二甲氨基吡啶(DMAP)的催化作用下,以甲苯为溶剂,合成新型清凉剂戊二酸单薄荷酯,采用正交试验优化了合成条件,得到较佳反应条件为:戊二酸酐和薄荷醇的摩尔比为1.4∶1,催化剂用量为薄荷醇摩尔分数的10%,回流温度下反应10 h,收率在80%以上.产物的结构通过红外光谱、核磁共振光谱和质谱进行了表征.利用热重-微商热重(TG-DTG)对戊二酸单薄荷酯的热失重、裂解温度进行了研究,通过在线裂解气相色谱/质谱联用(Py-GC/MS)技术对戊二酸单薄荷酯分别在无氧和有氧条件下,在300、600、750、900℃时的裂解产物进行了研究.结果表明:戊二酸单薄荷酯的裂解温度为305.1℃,在348.0℃时,样品总失重率接近100%;无氧和有氧条件下裂解产物的种类和数量随着温度升高而增多,有氧裂解产物数量多于无氧裂解;p-薄荷-3-烯、3-甲基-6-异丙基环己烯和薄荷醇是裂解的主要产物,具有致香和清凉作用.  相似文献   

10.
 组合应用热裂解、冷进样系统和气质联用仪(Py-CIS-GC/MS)对10个不同种类及等级的蜂蜜样品的有氧裂解行为进行了研究.在氧氮混合气体氛围(氧气和氮气按体积比9∶91混合)下,对10个蜂蜜样品在不同裂解温度(900,600,300℃)下的裂解产物挥发性成分进行分析比较,结果表明:①蜂蜜样品在900,600,300℃3个裂解温度下裂解,其共有裂解产物及半数以上样品共有裂解产物个数分别为:900℃,7个和20个,600℃,7个和16个,300℃,4个和6个;3个温度下均裂解出了糠醛、2,3-二氢-3,5-二羟基-6-甲基-4H-吡喃-4-酮、5-(羟甲基)-2-呋喃甲醛、D-阿洛糖4种产物;随着温度的降低,裂解产物个数、质量分减少,但各个温度下各蜂蜜样品主要裂解产物及其在产物中的质量分数差别不大;②3个温度下的裂解产物都以醛类、酮类、糖类以及呋喃、吡喃类物质为主;③部分蜂蜜挥发性成分原形转移进入裂解产物;④冷进样系统对热裂解产物的在线捕集更为完全.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
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。  相似文献   

15.
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.  相似文献   

16.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

17.
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.  相似文献   

18.
19.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

20.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

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