高频红外吸收法测定水泥中的硫

采用高频红外吸收法测定了水泥中硫的含量，并对样品作测定前的预处理(物理处理)，在测定中选用复合型助熔剂．解决了高频感应炉中顶吹氧气流的作用而导致的样品喷溅问题。该法可准确测定硫含量在0．001％～5％的水泥样中的硫，回收率为98、6％～102．5％，相对标准偏差为0．78％～1．35％。     

红外吸收法测定SiC的探讨

随着我国工业领域的持续发展,相关领域对Si C的需求量日益增大,基于此背景,本文对红外吸收法测定Si C进行探讨。该方法的大致步骤为:对Si C试样进行灼烧预处理→除去游离碳→校正仪器→用高频红外碳硫仪测定Si C。实验表明,此种测定方式步骤简单,用时较少,具有极大的市场竞争优势。     

碘量法与非分散红外吸收法测定二氧化硫浓度的对比

本文研究了用碘量法和非分散红外吸收法对二氧化硫浓度测定的对比.通过试验证明了.碘量法测得的二氧化硫的浓度均偏高.结果表明:非分散红外吸收法具有良好的准确度和精确度,适用于长时间测定二氧化硫混合气体浓度.     

高频红外吸收法测定普碳钢中碳含量

采用高频红外吸收法检测钢中碳含量,采用GBW 01205 (碳标准值0.455%)和纯钨作为助溶剂,采用统计分析的方法,研究标样含量和助溶剂用量对钢样中碳含量检测值稳定性的影响。结果表明,钢样用量0.200 0 g、助溶剂用量为1.5 g时,钢样碳含量检测值的波动性最小,碳含量检测值最接近真实值。相对标准偏差(RSD,n=5)<1%。     

红外吸收法测定催化剂中碳硫

介绍了红外吸收法测定催化剂中碳硫的分析方法。采用同心管燃烧炉高温灼烧试样,利用红外池检测试样中的碳、硫含量,探讨了试样量、空白值、燃烧温度、分析时间等因素对分析方法的影响,建立了测定碳、硫含量的工作曲线,总结了仪器分析的常见故障情况及处理方法。本方法快速,简单,准确度高,精密度好,完全能够满足生产需求。     

燃烧氧化——非分散红外吸收法测定废水中TOC影响因素的探讨

针对燃烧氧化—非分散红外吸收法测定废水中TOC的条件进行了优化。根据实际分析工作中的经验,对造成分析结果偏差的干扰因素——悬浮物、含盐量、pH和无机碳酸盐,提出了有效可行的解决办法,确保了分析结果的准确性、重复性。     

高频红外吸收法测定煤中的碳和硫

采用高频红外吸收法测定了煤中碳和硫的含量,并对样品作测定前的预处理(物理处理),在测定中选用复合型助熔剂,解决了高频感应炉中应顶吹氧气流的作用而导致的样品喷溅问题。该法可准确测定煤中硫含量0.001%～5%,碳含量0.001%～80%,回收率为93.91%～103.65%,RSD为0.83%～1.70%。     

硅碳管加热-红外吸收法测定煤中硫量

选择合适的分析条件,采用硅碳管加热-红外吸收法分析煤中的硫量。通过大量的试验证明该方法操作简便、快速、分析精度和准确度高,能够满足煤物质分析硫量的要求。     

红外吸收法测定碳铁中碳含量

以蔗糖为校准样品,采用红外吸收法测定碳铁中的碳含量。对实验数据进行线性回归,结果表明,测量允许差小于0.4%,能够满足碳铁的日常分析要求。     

电弧炉-红外吸收法测定钼铁中碳硫含量

应用电弧炉-红外碳硫分析仪,研究出一种测定钼铁中碳硫含量的简便方法。钼铁试样在电弧炉中通入氧气进行燃烧,碳和硫分别生成二氧化碳和二氧化硫,混合气体进入红外吸收池,二氧化碳和二氧化硫吸收某一特定波长的能量,吸收值与碳硫含量符合朗伯-比尔定律,使用含量相近的标准物质校准仪器,可以直接读出样品中碳硫含量。方法用于四种钼铁标准物质的碳硫测定,其相对标准偏差RSD(n=6),碳为1. 09%～3. 86%,硫为1. 87%～3. 95%,测定值与标准值相符合。     

电阻炉-红外吸收法测定页岩中固定碳含量

样品经70%王水处理,除去碳酸盐、硫化物以及部分有机质等。在600℃下,处理后的样品使用总碳分析仪灼烧180 s,再经950℃灼烧,测定样品中固定碳的含量。该方法快速、简便、准确,适合对页岩中低含量固定碳的测定。     

The formation of Co2C species in activated carbon supported cobalt-based catalysts and its impact on Fischer–Tropsch reaction

The cobalt carbide (Co₂C) species was formed in some activated carbon supported cobalt-based (Co/AC) catalysts during the activation of catalysts. It was found that the activity of Fischer–Tropsch reaction over Co-based catalysts decreased due to the formation of cobalt carbide species. Some promoters and pretreatment of activated carbon with steam could restrain the formation of cobalt carbide.     

Production of hydrocarbons in Fischer-Tropsch synthesis with Fe-based catalyst: Investigations of primary kerosene yield and carbon mass balance

The Fischer-Tropsch synthesis (FTS) of syngas was carried out using Fe-based catalysts in order to produce hydrocarbons (HCs) equivalent to kerosene, which is used as an alternative aviation fuel. The FTS was conducted in a downdraft continuous-flow-type fixed-bed reactor under a temperature of 533-573 K and a pressure of 3.0 MPa. The effects of reduction gases and time of the Fe-based catalyst, reaction temperature and the chemical species included in the Fe-based catalyst on the FTS were studied by focusing on primary kerosene yield and the carbon mass balance. The carbon mass balances in the study were almost 100%. In C6 + HCs, the selectivity of CO to the C11−C14 HCs equivalent to kerosene was found to be the second highest, the highest being its selectivity to C20 + HCs equivalent to wax. The amount of primary kerosene produced was maximum under the following conditions: the prepared Fe catalyst did not contain other chemical species, the feed ratio of the reduction gases H₂:CO:N₂ was 2:1:3, the catalyst reduction time was 8 h, and the FTS reaction temperature was 553 K.     

氦气替换法测定煤的真相对密度

就氦气替换法测定煤的真相对密度进行了研究。6个国家一级标准煤样的测定值都在标准值的不确定度范围之内;方法的准确度与国家标准方法没有偏倚,精密度与国家标准规定一致。     

A method to determine the relative value of the barriers of carbon chain growth and termination in Fischer-Tropsch synthesis: elementary reaction kinetics for chain growth

A method is established, by which the difference of the reaction activation barriers of carbon chain growth and termination in Fischer-Tropsch (FT) synthesis can be determined from experiments. A FT synthesis is carried out on Fe/Zn catalyst. We apply the method to analyze the experimental result and obtain the difference of reaction activation barriers of carbon chain growth and termination of -olefins on the catalyst.     

正交实验法对20~#碳钢在油田采出水中的应用研究

为了研究20#碳钢材料在油田上的适用范围,采用室内静态腐蚀挂片正交实验法,模拟油田采出水腐蚀性因素对20#碳钢在油田采出水中的应用进行了探讨。根据腐蚀失重法及试片的腐蚀速率分析,利用正交实验考察ρ(Ca2+)、ρ(HCO3-)、ρ(Cl-)、温度、pH值对20#碳钢腐蚀行为的影响。结果表明,对20#碳钢腐蚀性影响的强弱程度为温度pH值ρ(Cl-)ρ(HCO3-)ρ(Ca2+)。温度对20#碳钢起主要的影响,其腐蚀速率随温度升高而升高。同时,腐蚀速率随pH值增大而降低。其次,ρ(Cl-)的增加使低碳钢腐蚀加重,ρ(Ca2+)、ρ(HCO3-)对20#碳钢也有一定程度的腐蚀作用。     

A novel whitening test method of a sulfur-cured EPDM composite filled with carbon black in calcium cation solution

A simple and efficient whitening test method of a carbon black-filled sulfur-cured EPDM composite by formation of calcium stearate was established using Ca²⁺ solution and convenient analytical techniques. The sample was aged in 0.1 M CaCl₂ solution at 30–90 °C for 1 and 3 days. ATR-FTIR spectra of the aged sample surfaces displayed unique calcium stearate peaks. Level of the whitening of a rubber article can be determined by analysis of the cross section of the aged sample using an image analyzer and by analysis of calcium stearate on the aged sample surface using an ATR-FTIR.     

树脂吸附结合还原络合法去除盐酸中的铁离子

研究D201强碱性阴离子交换树脂（Cl型）吸附结合还原络合法进行盐酸除铁离子精制的过程,最佳试验条件为：采用D201强碱性阴离子交换树脂（Cl型）,还原剂硫代硫酸钠加入量1%（相对树脂质量,下同）,螯合剂EDTA加入量0.5%;在该条件下进行盐酸除铁离子精制,铁离子质量浓度降至0.1 mg/L以下。     

Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulse plasma CVD

A pulse plasma chemical vapor deposition (CVD) technique was developed for improving the growth yield of single-walled carbon nanotubes (SWNTs) with a narrow chirality distribution. The growth yield of the SWNTs could be improved by repetitive short duration pulse plasma CVD, while maintaining the initial narrow chirality distribution. Detailed growth dynamics is discussed based on a systematic investigation by changing the pulse parameters. The growth of SWNTs with a narrow chirality distribution could be controlled by the difference in the nucleation time required using catalysts comprising relatively small or large particles as the key factor. The nucleation can be controlled by adjusting the pulse on/ofF time ratio and the total processing time.     

Combustion synthesis of SiC-based ceramics reinforced by discrete carbon fibers with in situ grown SiC nanowires

This study proposes a combustion-based ceramic matrix composite processing technique intended on single-step in situ deposition of single-crystal SiC nanowires (SiC_nw) on the surface of carbon fibers (C_f) and formation of SiC_nw–reinforced SiC matrix. This was accomplished by Ta-catalyzed combustion of poly-(C₂F₄)-containing reactive mixtures with pre-mixed chopped C_f. Depending on the combustion conditions, carbon fiber surface is subjected either to formation of diffusion layers, ceramic particle incrustation or growth of continuous arrays of carbon-coated single-crystal SiC_nw with a nearly defect-free lattice, 10–50 nm diameter and 15–20 μm length. Thermodynamics, phase and structure formation mechanisms are explored, and the optimal conditions are outlined for reproducible C_f/in situ SiC_nw dual reinforcement of SiC-based ceramics. Hot pressing at 1500 °C produced C_f/in situ SiC_nw-reinforced ceramic SiC–TaSi₂ specimens with a relative density of 97%, 19 GPa Vickers hardness, 3-point flexural strength σ = 420 ± 70 MPa and fracture toughness K_1C = 12.5 MPa m^1/2.