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改进的喷淋-鼓泡式平衡器GC法测定海水中的Pco2 总被引:8,自引:0,他引:8
在全球变化研究中,海气变换平衡器是海水中二氧化碳分压(Pco2)直接测定的关键。本文在喷啉式平衡器和鼓泡式平衡器的技术基础上设计了新的喷淋-鼓泡式平衡器,就平衡器体积,平衡后气体进样方式,海气平衡时间等作了改进并与层流式平衡器进行了互校(气相色谱法现场测定)。经精密度分析和F法,t法显著性检验,本实验室的喷淋-鼓泡平衡器-气相色谱系统对大气和海水中Pco2的分析,都可以达到通量计算中Pco2的测定精密度需小于1%的要求,两种平衡器之间无显著性差异,改进的喷淋-鼓泡式平衡器能准确测定海水中的二氧化碳分压。 相似文献
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卢治平 《广东微量元素科学》1995,2(8):32-34
提出了在水源现场测定微量氟离子的离子选择性电极三点法,该法受测量条件影响较小,且操作简单,快速、灵敏度高,特别适用于野外现场分析。 相似文献
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1引言中等化学教材和高校无机化学教科书一般只介绍镁与二氧化碳的反应:那么究竟哪些金属能与二氧化碳反应?反应产物除金属氧化物和碳以外是否还有其他物质生成?对于这2个问题,目前主要有以下观点:(1)钠也能在二氧化碳中燃烧,生成氧化钠和碳[1]。(2)钠与二氧化碳的反应,由于钠比镁更活泼,因此更容易发生[2]。(3)镁在二氧化碳中燃烧时除生成氧化镁和碳外,还有一氧化碳气体生成,但镁不能在一氧化碳气体中燃烧[3]。其实,能与二氧化碳反应的金属不只是钠和镁2种。金属与二氧化碳反应趋势的顺序不同于金属活动性顺序,随温度的… 相似文献
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本文研究了分子筛对氦气中微量二氧化碳的静态吸附和对氩气中微量二氧化碳的连续动态吸附,及格连续流动法测定了载气氩和氦对分子筛吸附微量二氧化碳的影响。 相似文献
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利用微流路控制技术中心切割装置(Deans Switch)、两根色谱柱(PoraPLOT Q和Molsieve 5A)和3个检测器(脉冲氦离子化检测器、火焰光度检测器、热导检测器),建立了一种二维气相色谱分析系统,实现了海洋中多种示踪气体组分(氢气、甲烷、二氧化碳、硫化氢)的同时分析和精确测定。氢气、甲烷、二氧化碳、硫化氢的含量分别在2~1030、0.6~501、120~10500和0.2~49.1 μmol/mol范围内的校正曲线线性关系良好,检出限分别为0.51、0.17、82和0.08 μmol/mol,10次重复测定含量的相对标准偏差均小于10%。通过对南海天然气水合物区沉积物间隙水顶空气的测定,表明该方法方便、灵敏、可靠,易于实现海上现场测定;与以往采用多种分析方法分别测定示踪气体相比,大大节省了样品量。该方法适用于海洋天然气水合物、海底热液等资源的调查和海洋溶解态气体的研究等。 相似文献
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中国无烟煤焦气化活性的研究——水蒸气与二氧化碳气化活性的比较 总被引:2,自引:7,他引:2
在常压和920℃~1050℃下,采用热重方法,进行了六种中国典型无烟煤焦水蒸气与二氧化碳气化活性比较的研究。结果表明,无烟煤焦与水蒸气气化反应的活性与无烟煤的煤化程度相对应,无烟煤煤化程度越高,水蒸气气化反应活性越小。无烟煤焦与二氧化碳气化反应的活性与煤中矿物质的催化作用有密切关系,煤中矿物质的催化作用越大,二氧化碳气化反应活性越大。无烟煤焦与二氧化碳气化反应活性明显小于与水蒸气气化反应活性,后者比前者大10倍左右。初步探讨了无烟煤焦与水蒸气和二氧化碳的气化机理。 相似文献
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超临界CO2在高分子合成与制备中的应用 总被引:6,自引:0,他引:6
介绍超临界二氧化碳流体作为介质在高分子合成与制备中的研究进展。文中表明,可在超临界二氧化碳中实施氟代单体的自由基溶液聚合、甲基丙烯酸甲酯的分散聚合、丙烯酸的沉淀聚合、丙烯酰胺的反相乳液聚合以及异丁基乙烯基醚的阳离子聚合等多种聚合反应,可用超临界二氧化碳溶胀聚合法制备梯度共混物。此外,超临界二氧化碳还可用于聚合物分级和聚合物微孔、微纤与微球材料的制备等,显示出超临界二氧化碳是一种对环境无污染且价廉的 相似文献
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二氧化碳熄灭阶梯烛火实验的改进邓九皋(北京新街口中学100035)初三化学第三章中讲到二氧化碳性质时,安排一个演示实验(图略)。可以把二氧化碳象倾倒液体那样从一个容器中倒入另一个容器里。这是一个内涵丰富,现象明显,具有启发性的实验。因该实验不便于操作... 相似文献
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The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献
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Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared. 相似文献
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Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position. 相似文献
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Stepkowska E. T. Perez-Rodriguez J. L. Jimenez de Haro M. C. Sayagues M. J. 《Journal of Thermal Analysis and Calorimetry》2002,69(1):187-204
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6. 相似文献
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The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations
were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples
were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of
hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the
best fitting experimental data.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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