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1.
氧化钙碳酸化反应动力学研究   总被引:2,自引:4,他引:2  
采用单一扫描速率法(2℃/min)对氧化钙粉末在CO2气氛中的碳酸化反应进行了热分析动力学研究。结果表明,氧化钙碳酸化反应的最大转化速率在694℃,与在镁钙砂表面碳酸化改性工艺研究中得到的最佳炉温十分接近;而氧化钙的碳酸化反应可用n=2的Avrami-Erofeev随机成核、随后生长模式(机理)函数描述,相应的表观反应活化能为178kJ·mol-1,频率因子为3.4×108min-1。  相似文献   

2.
碳酸钙热分解反应动力学的不同方法研究   总被引:4,自引:0,他引:4  
因比较法和主曲线法在求算热分解动力学"三因子"时基本原理和处理方法不同,为此而探讨了2种方法处理的结果是否一致.利用热重分析(TGA)技术研究了碳酸钙热分解过程,通过这2种方法分别求算了碳酸钙热分解反应动力学"三因子".比较法结果:活化能Ea为174.00kJ·mol-1,指前因子A为9.63×106s-1,机理函数微分形式和积分形式分别为f(α)=2(1-α)1/2和g(α)=1-(1-α)1/2;主曲线法结果:活化能Eα=169.81 kJ/mol,指前因子A=3.84×106s-1,机理函数微分表达式为f(α)=2(1-α)1/1.57,积分表达式为g(α)=1-(1-α)1/1.57,2种方法所得结果基本吻合,说明这2种方法判定动力学"三因子"的一致性和可靠性.  相似文献   

3.
采用单一扫描速率(2℃/min)法对镁钙砂细粉的碳酸化反应进行了热分析动力学研究,为镁钙砂颗粒表面碳酸化改性反应动力学研究提供相关信息.研究结果表明,镁钙砂细粉碳酸化反应初期MgO的碳酸化和CaO碳酸化反应前期机理,可用n=2的Avrami-Erofeev随机成核、随后生长模式函数描述,后期(相对转化率大于33%~38%)则可用Jander或Ginstling-brounshtein三维扩散模式函数描述.同时,MgO碳酸化反应产生的体积效应导致CaO反应前期表观活化能大幅度降低.  相似文献   

4.
本文利用普适积分法、微分法来拟合求解50nm和500nm铁粉在10K?min-1、20K?min-1、30K?min-1和40K?min-1升温速率下的燃烧动力学参数,并确定纳米铁粉燃烧反应的动力学模型和最概然机理函数。30种机理函数的计算结果表明,50nm铁粉的活化能和指前因子的数值范围分别为90~130KJ?mol-1和103~108s-1,500nm铁粉的活化能和指前因子的数值范围分别为160~220KJ?mol-1和106~1011s-1,纳米铁粉的燃烧反应动力学模型为随机成核和随后生长,机理符合Avrami-Erofeev方程,最概然机理积分函数为G(α)=[-ln(1-α)]3,微分函数为f(α)= (1-a)[-ln(1-a)]-2/3。  相似文献   

5.
对-叔丁基杯[4]的热力学和热分析动力学   总被引:3,自引:0,他引:3  
用热重TG和DSC对杯芳烃对-叔丁基杯[4]热分解过程进行了研究,用多升温速率法和单升温速率法相结合的方法推断出了对-叔丁基杯[4]热分解的可能过程,并推断出了其可能的裂解反应动力学方程及热分析动力学参数;得出了结论脱包结甲苯的过程为23号机理函数,为三级反应过程,动力学方程为dα/dt=Ae-(E)/(RT)(1)/(2)(1-α)3;;表观活化能E为166.97 kJ*mol-1,指前因子A为1.67×1016 s-1;自身热分解脱去叔丁基的过程为1号机理函数,反应过程为一维扩散,动力学方程为dα/dt=Ae-(E)/(RT)(1)/(2)α;活化能E为248.89 kJ*mol-1,指前因子A为42.89 s-1.  相似文献   

6.
一种新的热分析动力学处理方法   总被引:8,自引:1,他引:8  
用一种新的方法对一水草酸钙(CaC2O4·H2O)脱水反应的热分析动力学三因子,即活化能Ea、指前因子A和反应机理函数f(α)进行了求取.此方法可分为三步:(1)用迭代的方法求取Ea值;(2)用Popescu的方法求取反应的f(α);(3)由以上两步所得的结果求取指前因子A.此方法有两大优点:对动力学参数Ea和f(α)分别进行求取,从而使f(α)求取的准确性不因Ea值求取是否存在误差而受影响;在f(α)的求取中没有引入任何积分误差,从而提高了计算结果的准确性.  相似文献   

7.
热分析动力学的多升温速率等温法及其应用   总被引:2,自引:0,他引:2  
提出了多升温速率等温法确定热分析动力学可能的机理函数g(α);用迭代的等转化率法求出较为可靠的活化能Ea;在Ea和g(α)的基础上计算出指前因子A.用该法对二水草酸镍(NiC2O4·2H2O)脱水反应的热分析动力学三因子进行了研究,得出Ea为96.55 kJ/mol;A为7.746×107~9.415×107s-1;其对应的机理函数为随机成核和随后生长(Avrami-Erofeer),调节函数Am,其积分形式g(α)=[-ln(1-α)]1/m和微分形式f(α)=m(1-α)[-ln(1-α)]1-1/m,调节因子m=1.55~1.70.用该法求算动力学三因子,结果可靠,重现性较好,具有一定的可比性.  相似文献   

8.
在水溶液中用硫酸铜和邻苯二甲酸氢钾反应合成了Cu(C8H5O4)2·2H2O,并得到了该配合物的单晶体,通过元素分析、IR光谱、TG-DTA对产物进行鉴定.以Achar法、Coats-Redfern法对TG曲线数据进行非等温动力学拟合,得到第一步脱水反应的动力学方程为dα/dt=Aexp(-E/RT)2(1-α)[-1n(1-α)]1/2,活化能E=135.0kJ/mol,指前因子lg(A/s-1)=14.89;第二步热分解的动力学方程为:dα/dt=Aexp(-E/RT)[-ln(1-α)]-1,活化能E=289.7kJ/mol,指前因子lg(A/s-1)=26.86.  相似文献   

9.
采用共沉淀法制备了不同铈锆比的ZrxCe1-xO2(x=0,0.1,0.3,0.5,0.7,0.9,1.0)固溶体.利用热分析方法研究了Zrx(OH)4x.Ce1-x(OH)4(1-x)体系的热分解过程,并运用XRD对其热分解产物进行了表征.实验表明Zrx(OH)4x.Ce1-x(OH)4(1-x)在空气中的热分解是一步完成的,随着锆含量的增加分解温度逐渐提高.应用微分法和积分法相结合对该分解过程的分解机理进行了推测,得出了一系列分解反应的表观活化能E和指前因子A.发现其热分解反应遵循Zhuralev-Lesokin-Tempelman三维扩散机理,其动力学方程为:f(α)=3/2(1-α)4/3[(1-α)-1/3-1]-1;g(α)=[(1-α)-1/3-1]2,其表观活化能大小与样品中的锆含量有关.  相似文献   

10.
报道了用热重法(TG)研究替硝唑(Tinidazole,TNZ)原药及片剂中替硝唑热分解非等温动力学以及药物的稳定性,并对用热重分析仪测定片剂含量的方法进行了探讨.推断出原药热分解过程为零级反应,其动力学方程为dα/dt=Ae-(Ea)/(RT),热分解反应活化能Ea为99.7kJmol-1,指前因子A为3.60×107s-1;片剂中替硝唑的热分解过程为三维扩散级反应,其动力学方程为dα/dt=Ae-(Ea)/(RT)3/2(1+α)2/3/[(1+α)1/3-1],活化能Ea为105.1kJmol-1,指前因子A为1.08×106s-1.实验表明替硝唑原药具有较高的热解活化能,热稳定性较好;在片剂中热分解机理和分解活化能发生改变,说明赋形剂对药物的热稳定性有一定影响.根据得到的热分解反应的机理函数和动力学参数,得到片剂有效存贮期与贮存温度的关系曲线,估算出在室温(25℃)下,分解率为10%时药物的存贮期为26.7年,分解率为5%时所需要的时间约为6.9年.  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 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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

15.
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   

16.
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.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
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   

19.
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   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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