芳香类重质油基针状焦的制备及表征

针状焦作为一种应用广泛的人造炭素材料,是制备超高功率石墨电极和锂离子电池负极用石墨的重要原料。原料的基础物性对针状焦的品质影响极大,从而进一步影响石墨材料的性质。为进一步考察芳香族重质油制备高品质针状焦的可行性,分别以混合油(MO)和乙烯渣油馏分油(EPO)为原料,利用延迟焦化装置进行公斤级试验。分别以FTIR和TGA解析重质油的分子结构以及热解特性,从光学组织结构、表面形貌、晶体结构、微晶分布形式以及导电性能五个方面分析针状焦性质。研究结果表明：MO和EPO的芳香性指数(I_ar)分别为0.592 7和0.569 4,支链化指数(CH₃/CH₂)为0.351 6和0.228 3,得到的针状焦MO-Coke和EPO-Coke中纤维状结构含量分别为47.68%和57.40%。两种针状焦MO-Coke和EPO-Coke表面光滑且呈类石墨片层结构,微晶堆垛高度分别为2.73 nm和3.50 nm,理想石墨微晶含量达到10.58%和16.43%,电阻率仅为489μΩ·m和471μΩ·m。换句话说,芳香族重质油MO和EPO是制备高品...     

薄层色谱扫描仪检定方法的研究

根据薄层色谱扫描仪计量溯源空白的现状,探寻一套简单适用的检定方法,并详细介绍检定过程,给相关使用单位和计量检定部门提供一定的技术指导.     

气相色谱-质谱法测定夜来香种子油中的脂肪酸

利用气相色谱-质谱联用技术对夜来香种子油中的脂肪酸(经甲酯化后)进行分离和定性,共鉴定出二十种脂肪酸。并用归一化法确定出各成分在夜来香种子油中的相对含量。对所得的结果进行了讨论。     

虾仁中氯霉素残留量的气相色谱测定

建立了用配有电子俘获检测器(ECD)的气相色谱仪来测定虾仁中的氯霉素含量的方法。试样用乙酸乙酯提取,正己烷去杂,硅胶柱纯化.BSTFA+TMCS(99:1)试剂硅烷化。以GC-ECD方式测定,外标法定量。当添加水平为0.2×10~9～1.0×10~(-9)μg/kg时,回收率为70%～110%;相对标准偏差为1.0%～5.0%;线性相关系数,r>0.998。     

毛细管气相色谱法测定水中氯苯类化合物的方法研究

建立了毛细管气相色谱法同时测定水中氯苯类化合物的方法。用苯作溶剂提取,经HP-5色谱柱分离后用ECD检测。水中检出限为0．003-0．25ug／L比比地表水环境质量标准GB3838—2002中的限值低1—4个数量级。本方法线性相关性良好,方法相对标准偏差为0．7％～11.8％,实际样品加标回收率为92％～107％。     

薄层色谱同板检测冰片与薄荷脑的展开剂摸索方法探讨

笔者针对目前制剂中冰片与薄荷脑成分常用检测方法存在的问题,通过大量的实验,摸索出用薄层色谱法同板检测冰片与薄荷脑的方法,并对展开剂系统进行了筛选,摸索出具有设备、操作简单,检测费用低;方法专一性和准确性强;检测周期短;易于推广应用等特点的检测方法。     

氢燃料电池用氢气中甲酸的测定——气相色谱法

阐述了采用气相色谱法测定氢燃料电池用氢气中甲酸含量。该方法准确、可靠,便于操作。     

清溪乌鳖油脂肪酸的气相色谱-质谱联用分析

采用气相色谱-质谱法对清溪乌鳖油脂中脂肪酸组成进行分析。共检测到22种脂肪酸,其中单不饱和脂肪酸6种,多不饱和脂肪酸9种,饱和脂肪酸7种。清溪乌鳖富含ω-3脂肪酸,含量达16.69%。此外清溪乌鳖油中9-十八碳烯酸（油酸）和9-十六碳烯酸（棕榈油酸）的含量也较高。本研究为清溪乌鳖油在生物制药和营养保健品领域的开发应用提...     

汞灯辅助MOCVD SnO2薄层晶体的结构与透明导电性研究

采用x—射线衍射(XRD)、高能电子衍射(RHEED)、扫描电子显微镜(SEM)和紫外可见吸收谱(UV)等技术研究了在汞灯(ML)辅助下进行有机金属化学气相沉积(MOCVD)所得本征及掺杂SnO_2薄层晶体的结构和透明导电性。实验指出,采用汞灯辅助有机金属化学气相沉积(ML-MOCVD)SnO_2薄层晶体比无汞灯辅助的有机金属化学气相沉积(MOCVD)膜层生长速度快,结晶粒度大且其透明导电性能更好。本文对ML-MOCVD SnO_2薄层晶体的结晶粒度与生长温度的关系、掺杂对结晶取向的影响以及可见光透过率、导电性能等进行了较详细的研究。结果指出,ML-MOCVD是获得透明导电优质薄层SnO_2晶体材料的最佳途径。     

一种快速测定啤酒酒精含量的方法-气相色谱法

本文介绍了用气相色谱法快速测定啤酒酒精含量的方法。与比重瓶法相比,该法具有准确快速的优点,实验证明其检测结果准确,再现性好,适合于啤酒厂及检测部门检验。     

薄层扫描仪校准方法探讨

薄层扫描仪已广泛应用于医药的研制和生产领域,但目前国内还没有相关的检定规程或校准规范,无法保证其计量性能的准确一致。文章简要介绍了薄层扫描仪的作用、工作原理及结构,探讨了薄层扫描仪的校准项目和校准方法,对其操作步骤及性能要求做了规定,为薄层扫描仪的计量校准提供了一种可行的方法和依据。     

Stability indicating HPTLC determination of linezolid as bulk drug and in pharmaceutical dosage form

A simple, selective, precise, and stability-indicating high-performance thin layer chromatographic method of analysis of Linezolid both as a bulk drug and in formulations was developed and validated in pharmaceutical dosage form. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-acetone (5:5, v/v). This system was found to give compact spots for Linezolid (R_f value of 0.29 ± 0.01). Linezolid was subjected to acidic, alkali hydrolysis, oxidation, and photodegradation. The degraded products also were well separated from the pure drug. Densitometric analysis of Linezolid was conducted in the absorbance mode at 254 nm. The linear regression data for the calibration plots showed good linear relationship with r² = 0.997 ± 0.001 in the concentration range of 300-800 ng/spot. The mean value of correlation coefficient, slope, and intercept were 0.998 ± 0.003, 0.15 ± 0.009, and 19.52 ± 1.66 respectively. The method was validated for precision, accuracy, ruggedness, and recovery. The limits of detection and quantification were 20 ng/spot and 50 ng/spot, respectively. The drug undergoes degradation under acidic and basic conditions, oxidation and photo degradation. All the peaks of degraded product were resolved from the standard drug with significantly different R_f values. This indicates that the drug is susceptible to acid-base hydrolysis, oxidation, and photo degradation. Statistical analysis proves that the method is reproducible and selective for the estimation of the said drug. Because the method could effectively separate the drug from its degradation products, it can be used as a stability indicating one.     

表面活性剂丁二酸二异辛酯磺酸钠含量测定方法研究

本文根据色谱法原理,用薄层色谱与柱色谱相结合,定量分离出表面活性剂丁二酸二异辛酯磺酸钠,然后加碱皂化求出其含量。该法对本表面活性剂的生产控制和应用研究是很有实际意义的。     

BiFeO3 films on steel substrate by the citrate method

We deposited BiFeO₃ films on stainless steel substrates using a simple low-temperature wet-chemical route. Bismuth and iron nitrates were used as metal source and citric acid as chelating agent to prepare a water solution and deposit the film by dipping the steel substrate in the viscous solution. We have investigated the composition, crystallinity and structure of the BiFeO₃ film on steel by X-ray diffraction, X-ray photoelectron spectroscopy, high resolution scanning electron microscopy, conventional and high resolution transmission electron microscopy, and energy dispersive spectroscopy techniques. The film deposited on the steel substrate has two sublayers: a very thin (about 100 nm) nanocrystalline layer, with crystallite size of few nanometers, and a thicker (below 1 μm) crystalline layer.     

A new Fourier transform infrared method for the determination of moisture in edible oils

A rapid, practical, and accurate Fourier transform infrared (FT-IR) method for the determination of moisture content in edible oils has been developed based on the extraction of water from oil samples into dry acetonitrile. A calibration curve covering a moisture content range of 0-2000 ppm was developed by recording the mid-infrared (MIR) spectra of moisture standards, prepared by gravimetric addition of water to acetonitrile that had been dried over molecular sieves, in a 500 microm ZnSe transmission flow cell and ratioing these spectra against that of the dry acetonitrile. Water was measured in the resulting differential spectra using either the OH stretching (3629 cm(-1) or bending (1631 cm(-1)) bands to produce linear standard curves having standard deviations (SDs) of approximately +/-20 ppm. For moisture analysis in oils, the oil sample was mixed with dry acetonitrile in a 1:1 w/v ratio, and after centrifugation to separate the phases, the spectrum of the upper acetonitrile layer was collected and ratioed against the spectrum of the dry acetonitrile used for extraction. The method was validated by standard addition experiments with samples of various oil types, as well as with oil samples deliberately contaminated with alcohols, hydroperoxides, and free fatty acids to investigate possible interferences from minor constituents that may be present in oils and are potentially extractable into acetonitrile. The results of these experiments confirmed that the moisture content of edible oils can be assessed with high accuracy (on the order of +/-10 ppm) by this method, thus providing an alternative to the conventional, but problematic, Karl Fischer method and facilitating the routine analysis of edible oils for moisture content.     

Ni/Zr-Co-Re堆栈层薄膜吸气剂的吸气性能及Ni作用机理研究

采用磁控溅射的方法制备了带有Ni保护层和Zr-Co-Re(Re代表稀土元素)主体层的堆栈层薄膜吸气剂。通过X射线光电子能谱仪(XPS)分析了薄膜吸气剂内部O元素的含量分布,研究了薄膜吸气剂中Ni层的防氧化作用和机理。研究表明:(1)Ni/Zr-CoRe堆栈层薄膜吸气剂在160℃保温3h的条件下可以有效激活,并具有高于Zr-Co-Ni单层薄膜吸气剂的吸气性能;(2)Ni保护层降低了吸气剂的被氧化程度,促进了表面吸附的H2分子的解离和扩散。     

A method for dynamic fracture toughness determination using short beams

This paper deals with dynamic fracture toughness testing of small beam specimens. The need for testing such specimens is often dictated by the characteristic dimensions of the end product. We present a new methodology which combines experimentally determined loads and fracture time, together with a numerical model of the specimen. Calculations are kept to a minimum by virtue of the linearity of the problem. The evolution of the stress intensity factor (SIF) is obtained by convolving the applied load with the calculated specimen response to unit impulse force. The fracture toughness is defined as the value of the SIF at fracture time. The numerical model is first tested by comparing numerical and analytical solutions (Kishimoto et al., 1990) of the impact loaded beam. One point impact experiments were carried out on of commercial tungsten base heavy alloy specimens. The robustness of the method is demonstrated by comparing directly measured stress intensity factors with the results of the hybrid experimental-numerical calculation. The method is simple to implement, computationally inexpensive, and allows testing of large sample sizes, without restriction on the specimen geometry and type of loading.     

新型液-液微萃取--气相色谱法测定海水中的有机氯农药

本文采用了一种新型的液---液两相微萃取技术作为海水样品前处理方法,对海水中的八种有机氯农药(α-BHC,β-BHC,γ-BHC,δ-BHC,p,p,-DDE,o,p,-DDT,p,p,-DDD,p,p,-DDT)进行萃取、富集和分离,采用配微池电子捕获检测器气相色谱法分析测定。对影响萃取效率的因素进行了优化。结果表明,在优化条件下,六六六、滴滴涕在1.0-100.0μg/L范围内有良好的线性关系,R≥0.9963,检测限为0.004~0.016μg/L。     

厚/薄板振动分析的样条无单元法

建立了厚/薄板振动分析的样条无单元法计算格式,对整个求解区域仅需少量的结点离散,无需单元分划,把挠度和剪应变作为全局的场变量,采用双向三次B样条基函数乘积的线性组合构造场函数,可以充分发挥无单元法及三次B样条基函数的优点。计算结果表明该方法适用于不同厚度,不同边界的板的动力特性分析,无剪切闭锁现象,且精度高,收敛快,未知量少,程序简便。