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排序方式: 共有438条查询结果,搜索用时 15 毫秒
81.
主要研究了多胺-硫脲缩聚物对环氧-聚酰胺固化体系的促进作用。通过示差扫描量热,对改性前后固化反应动力学多种参数进行了计算,说明了这种增强作用是由于多胺-硫脲缩聚物的加入使体系动力学反应的前置因子和反应速率常数大幅度提高。在此基础上研制的环氧树脂/聚酰胺/缩聚物胶粘剂具有高强度,高耐湿热性,室温下可快速固化的特点。 相似文献
82.
城市污水处理厂污泥热解机理 总被引:1,自引:0,他引:1
本研究采用热重分析仪对南昌市青山湖污水污泥进行热重分析实验,分别获得了20 K/min和40 K/min加热速率下污泥的TG-DTG曲线,得出了污水处理厂污泥的热解特性。根据实验结果对干燥污泥热解过程进行了分析且利用积分法确定了热解机理,求出反应动力学参数-频率因子A、活化能E。 相似文献
83.
84.
In order to improve the deposition rate and microstructure of pyrocarbon, nickel was introduced by electroplating on carbon fibers and used as a catalyst during the deposition of pyrocarbon at 1000 C using methane as a precursor gas. The distribution of nickel catalyst and the microstructure of pyrocarbon were characterized by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray diffraction(XRD), and Raman micro-spectrometry. Results show that nano-sized nickel particles could be well distributed on carbon fibers and the pyrocarbon deposited catalytically had a smaller d002 value and a higher graphitization degree compared with that without catalyst. In addition, the deposition rate of pyrocarbon in each hour was measured.The deposition rate of pyrocarbon in the first hour was more than 10 times when carbon cloth substrates were doped with nickel catalysts as compared to the pure carbon cloths. The pyrocarbon gained by rapid deposition may include two parts, which are generation directly on the nickel catalyst and formation with the carbon nanofibers as crystal nucleus. 相似文献
85.
通过冻融和化学侵蚀试验,研究了NW-056A机场道面除冰液对道面水混混凝土耐久性的影响以及在道面除冰液环境下两种新型混凝土保护剂的防护效果。结果表明:①混凝土在道面除冰液中冻融后表面无明显剥落现象,相对动弹模损失率比在水中小很多,道面除冰液延缓了混凝土的冻融破坏:②混凝土在道面除冰液常温浸泡下表面无剥蚀现象,但强度比在水中降低很多,因此存在化学腐蚀.且主要表现为对混凝土内部结构的缓慢损伤;(④两种新型混凝土保护剂均对预防混凝土的冻融破坏以及除冰液环境下的腐蚀破坏起到一定作用,涂刷混凝土保护剂是提高混凝土道面耐久性的有效方法。 相似文献
86.
FINITE DIFFERENCE MODEL FOR SIMULATION OF DENSIFYING CARBON-CARBON COMPOSITES BY CHEMICAL VAPOR INFILTRATIONP ROCESSES 总被引:1,自引:0,他引:1
NomenclaturesA0—coeficientoftheArheniusequationC(n)—hydrocarbonconcentrationinunit(n)(mol/cm3)C0—hydrocarbonconcentrationatex... 相似文献
87.
S.I. Bartsev V.V. Mezhevikin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
Searching for extraterrestrial life attracts more and more attention. However this searching hardly can be effective without sufficiently universal concept of life origin, which incidentally tackles a problem of origin of life on the Earth. A concept of initial stages of life origin is stated in the paper. The concept eliminates key difficulties in the problem of life origin, and allows experimental verification of it. According to the concept the predecessor of living beings has to be sufficiently simple to provide non-zero probability of self-assembling during short (in geological or cosmic scale) time. In addition the predecessor has to be capable of autocatalysis, and further complication (evolution). A possible scenario of initial stage of life origin, which can be realized both on other planets, and inside experimental facility is considered. In the scope of the scenario a theoretical model of multivariate oligomeric autocatalyst is presented. Results of computer simulation of two versions of oligomeric autocatalytic reactions are presented. It is shown that the contribution of monomer activation reaction is essential, and in some cases autocatalysis in polymerizing reaction can be achieved without catalyzing proper monomer binding reaction. 相似文献
88.
It is commonly believed that comets are made of primordial material. As a consequence, they can reveal more information about
the origin of our solar system. To interpret the coma composition measurements of comet Churyumov–Gerasimenko that will be
collected by the Rosetta mission, models of the coma chemistry have to be constructed. However, programming the chemistry
of a cometary coma is extremely complex due to the large number of species and reactions involved. Moreover, such a program
needs to be very flexible as one may want to extend, change, or update the set of species, reactions, and reaction rates.
Therefore, we developed software to manage a database of species and reactions and to generate code automatically to compute
source/loss balances. This database includes the data from the UMIST database and the ion–molecule reactions collected by
V.G. Anicich. To use all these databases together, a lot of practical problems need to be solved, but the result is an enormous
source of information about chemical reactions that can be used in chemical models, not only for comets but also for other
applications. 相似文献
89.
90.
用准稳态方法建立碳氢燃料点火燃烧的简化化学反应动力学模型 总被引:2,自引:0,他引:2
基于“准稳态”方法建立了一套碳氢燃料点火燃烧的化学反应动力学模型简化方法和相应的软件SPARCK,并从甲烷点火燃烧的GRI2.11详细基元反应动力学模型出发简化得出了包含16个组分12步总包反应形式的简化化学反应动力学模型,从庚烷点火燃烧的详细基元反应动力学模型出发简化得出了包含25个组分21步总包反应形式的简化化学反应动力学模型。通过其计算结果与CARM软件导出简化模型的计算结果和典型激波管试验结果的对比可以看出,本文简化得到的简化反应动力学模型能较为有效地再现详细基元反应模型的反应机理,简化模型的计算精度与CARM软件导出简化模型的计算精度相当。与详细基元反应动力学模型相比,简化模型有效地减少了反应组分,在工程计算中有比较好的应用前景。 相似文献