检索结果-南通市图书馆

Thermal and elemental analysis of the combustion chamber deposits in a large-scale two-stroke marine diesel engine

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第10期58卷 1717-1725页

作者： ZHANG XuSheng ZENG XiangMing SUN XiuCheng DENG Biao PENG GuanYun XIE HongLan WU ZhiJun XIAO TiQiao Merchant Marine College Shanghai Maritime University Shanghai Institute of Applied Physics Chinese Academy of Sciences School of Automotive Studies Tongji University

It is of significance to understand the chemical content of carbon deposits in the large-scale two-stroke(LSTS) marine diesel engine because of adverse effect on the engine performance, oil consumption and emissions. In this work, two different combustion chamber deposits in an LSTS marine diesel engine were studied using thermogravimetry analysis(TGA), elemental analysis(EA) and synchrotron X-ray fluorescence(SXRF). One was on the piston top and the other on the piston land, termed PTCD and PLCD, respectively. For the PTCD sample, the 97% residue in the TGA and 1.4% carbon content in the EA indicated the main compositions of PTCD were metal salts or oxides and ashes, significantly different from the previous findings of the highest carbon content in deposits from the small four stroke engines. The different chemical content between PTCD and PLCD implied higher thermal load in the LSTS marine diesel engine led to a nearly complete thermal decomposition of PTCD. The higher calcium content in PTCD and PLCD indicated the additives of cylinder oil should be the main source of metal content of PTCD and PLCD. Calcium distribution in the SXRF results was indicative of the potential layered structure in PTCD and PLCD. In addition, the appearance of iron on the surface against the piston in PTCD and PLCD indicated iron oxides formation between carbon deposit and piston materials.

关键词： combustion chamber deposits thermogravimetry analysis elemental analysis marine diesel engine synchrotron X-rayfluorescence spectrometry

Multi-elemental analysis and 2D Image Mapping within Roots, Leaves and Seeds from O. glaberrima Rice Plants Using Micro-PIXE Technique

在线全文

学校读者我要写书评

暂无评论

World Journal of Nuclear Science and Technology 2024年第2期14卷 97-106页

作者： Alassane Traore Anna Ndiaye Christopher Bongani Mtshali Manneh Baboucarr Jean Paul Latyr Faye Daouda Mbodj Kandiaba Traore Tapha Gueye Ababacar Sadikhe Ndao Département de Physique Faculté des Sciences et Techniques Université Cheikh Anta Diop Dakar Senegal Département de Chimie Faculté des Sciences et Techniques Université Cheikh Anta Diop Dakar Senegal Tandetron Laboratory IBA Group iThemba LABS Cape Town South Africa Africa Rice Center St. Louis Senegal

Understanding metal accumulation at organ level in roots, leaves and seeds in O. glaberrima (OG) is crucial for improving physiological and metabolic aspects in growing Asian and African rice in salted areas. The micro-analytical imaging techniques are required to reveal its accumulation and distribution within plant tissues. PIXE studies have been performed to determine different elements in rice plants. The existing microbeam analytical technique at the iThemba LABS will be applied for the 2D image mapping of fresh rice tissues to perform a concentration of low atomic mass elements (such as Al, Si, P, S, Cl, Ca, Ti, Mn, Fe, Cu, Br, Zn and K) with detection limits of typically 1-10 μg/g. Comparison of the distribution of the elements between leaves, root and seed samples using uptake and distribution of elements in particular environmental conditions with potential amount of salt in water have been performed. We are also expecting to indicate metal exclusion as salt tolerance strategies from leaves, root, and seed compartments using matrix correlation between samples and between elements on rice species.

关键词： PIXE 2D Mapping Rice Concentration elemental analysis

Carbonization mechanism of bamboo (phyllostachys) by means of Fourier Transform Infrared and elemental analysis

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Forestry Research 2003年第1期14卷 75-79页

作者：左宋林高尚愚阮锡根徐柏森南京林业大学

通过测定在200-600℃炭化竹材得到的固体产物的碳、氢、氧元素的含量及它们的红外光谱,研究了在炭化过程中竹材中半纤维素、纤维素及木素的变化规律。结果表明,结合元素分析,红外光谱分析方法是研究竹材炭化机理的有效手段。在200℃以前... 详细信息

通过测定在200-600℃炭化竹材得到的固体产物的碳、氢、氧元素的含量及它们的红外光谱,研究了在炭化过程中竹材中半纤维素、纤维素及木素的变化规律。结果表明,结合元素分析,红外光谱分析方法是研究竹材炭化机理的有效手段。在200℃以前,竹材中的半纤维素和纤维素的大量羟基断裂,并结合成水而失去。在200-250℃之间,竹材中的纤维素被降解,其中的吡喃型环也遭到破坏。并且木素中的甲氧基也被脱去。竹材中的木素网状结构在250-400℃之间遭到完全的破坏。竹炭中的碳原子在600℃已基本上完成了芳环化。图3表2参15。

关键词： Bamboo Carbonization Fourier Transform infrared elemental analysis

Characterization of humic acids extracted from the sediments of the various rivers and lakes in China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2008年第11期20卷 1294-1299页

作者： HE Mengchang SHI Yehong LIN Chunye State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing 100875 China

The humic acids (HAs) isolated from the sediments of the various rivers,lakes,and reservoirs in China were studied using elemental analyzer,fourier transform infrared (FT-IR),and CP/MAS 13C nuclear magnetic resonance (NMR) *** results showed that the HAs were characterized by some common chemical and physicochemical properties,but they also pose some differences in the C-containing functional *** C/N,C/H,O/C,and O/H ratios differ widely for the various HAs,showing that the elemental comp...

关键词： CP/MAS 13C NMR spectroscopy elemental analysis fourier transform infrared spectroscopy humic acids surficial sediment structural characteristics

SPECTRAL AND CHEMICAL MONITORING OF CYCLO-ADDITION REACTION OF CO_2 WITH POLY(MMA-co-GMA) COPOLYMERS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2012年第5期30卷 727-734页

作者： M.Yadollahi H.Bouhendi M.J.Zohuriaan-Mehr K.Kabiri Iran Polymer and Petrochemical Institute(IPPI) P.O.Box 14965-115TehranIran

This paper deals with the monitoring cyclo-addition of CO2 to methyl methacrylate （MMA）-glycidyl methacrylate （GMA） copolymers using spectral （IH-NMR and FTIR） and chemical （elemental analysis and titration） methods. Thus, poly（MMA-co-GMA）, was first prepared via solution polymerization. The copolymer was then treated with CO2 gas flow in the presence of cetyltrimethyl ammoniumbromide as a catalyst. In terms of the carbonation reaction time, the terpolymer poly（MMA-eo-GMA-co-2-oxo-l,3-dioxolane-4-yl-methyl methacrylate） was prepared in various yield of CO2 fixation （〉 90%）. The peak intensity changes in the 1H-NMR and FTIR spectra provided excellent demonstrative techniques to monitor the carbonation reaction progression. In a comparative analytical viewpoint, the NMR and elemental analysis were recognized to be the most accurate ways to follow the cyclo-addition reaction progression. However, titration was recognized to be the most preferred method, because it is a very inexpensive, facile and available method with a reasonable cost- accuracy balance.

关键词： Carbon dioxide Cyclic carbonate Glycidyl methacrylate Titration 1H-NMR elemental analysis FTIR.

Quantitative analysis of saindha salt using laser induced breakdown spectroscopy and cross-validation with ICP-MS

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2020年第7期22卷 51-58页

作者： M QASIM M ANWAR-UL-HAQ M SHER AFGAN S U HAQ M A BAIG Department of Physics University of SargodhaSargodha 40100Pakistan Department of Energy&Power Engineering Tsinghua-BP Clean Energy CenterTsinghua UniversityBeijing 100084People’s Republic of China National Institute of Lasers and Optronics(NILOP) NiloreIslamabad 45650Pakistan National Center for Physics Quaid-i-Azam University CampusIslamabad 45320Pakistan

Saindha salt is considered to be more advantageous than the other edible salts for the patients suffering from diabetes,blood pressure and kidney *** explore the constituent elements of this salt,laser induced breakdown spectroscopy(LIBS) has been exploited for its qualitative and quantitative *** third harmonic(355 nm) of a Q-switched Nd:YAG laser has been used to produce the saindha salt plasma and the time integrated optical emission spectra were registered using a set of six miniature spectrometers covering the spectral range of 230-805 *** spectroscopic analysis of the emission spectra predominately revealed numerous neutral or singly ionized emission lines of Ca,Mg,Na,K,Fe,Sr,Si,Li and *** laser produced plasma was characterized by calculating the electron temperature from the Boltzmann plots and the electron number density from the Stark broadened line profile as a function of laser irradiance and distance from the target *** relative concentration of the constituent elements was extracted by the integrated line intensities of the strongest spectral line of each element using the self-calibration-LIBS(SC-LIBS) and one-line calibration free-LIBS(OLCF-LIBS) *** cross-validation,the LIBS results have been compared with that obtained from the inductively coupled plasma-mass spectroscopy(ICP-MS) showing good agreement.

关键词： elemental analysis CF-LIBS plasma parameters

Characterization of humic substances in bio-treated municipal solid waste landfill leachate

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2012年第5期6卷 711-716页

作者： Guangxia QI Dongbei YUE Yongfeng NIE Key Laboratory for Solid Waste Management and Environment Safety(Ministry of Education) Tsinghua UniversityBeijing 100084China

Considerable organic matter remains in muni- cipal solid waste landfill leachate after biological treat- ments. Humic substances （HSs） dominate the organic matter in bio-treated landfill leachate. In this study, the HSs from landfill leachate treated by membrane bioreactor （MBR-HSs） were analyzed via elemental analysis, ultra- violet-visible spectroscopy, Fourier transform infrared spectroscopy, and charge polarized magic-angle spin- ning-~3C-nuclear magnetic resonance. The characteristic absorption in the UV wavelength range indicated the presence of high C=C and C=O double bonds within the MBR-HSs. Compared with commercial HSs, MBR-HSs had lower carbon content [48.14% for fulvic acids （FA） and 49.52% for humic acids （HA）], higher nitrogen content （4.31% for FA and 6.16% for HA）, lower aromatic structure content, and higher carbohydrate and carboxylic atoms of carbon content. FA predominantly had an aliphatic structure, and HA had less condensed or substituted aromatic ring structures than natural HA. The aromatic carbon content of MBR-HSs was lower than that of humus-derived HSs but higher than that of waste- derived HSs, indicating that MBR-HSs appeared to be more similar to humus-derived HSs than waste-derived HA.

关键词： bio-treated landfill leachate humic sub-stances elemental analysis spectroscopic characteristics

ELECTROCHEMICAL POLYMERIZATION OF ANILINE IN PHOSPHORIC ACID AND THE PROPERTIES OF POLYANILINE

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2004年第5期22卷 405-415页

作者：穆绍林 YongKong JunWu DepartmentofChemistry YangzhouUniversityYangzhou225002China

The behavior of the electrochemical polymerization of aniline in a weak acid, phosphoric acid, is very similar to that in strong acids, i.e. its polymerization rate increases quickly with the electrolysis time. The FTIR spectra of polyaniline samples synthesized in phosphoric acid indicate that the counter ion H2PO4- is present in both the oxidized form and the reduced form of polyaniline. The counter ion plays an important role in adjusting the pH value at the electrode surface of polyaniline during the oxidation and reduction processes. As a result, a pair of redox peaks still appear in cyclic voltammograms of polyaniline in a solution of sodium sulfate of pH 5.5 and in a solution of NaH2PO4 of pH 7.0, respectively, at low potential scan rate; and the color of polyaniline film also changes with applied potential at pH 7.0. Thus, the pH region for the electrochemical activity and the electrochromism of polyaniline is extended to pH 5.5 for a solution of sodium sulfate and to pH 7.0 for a solution of NaH2PO4. The conductivity of polyaniline is 3.3 S cm-1, depending on the concentration of phosphoric acid used in the stage of polymerization of aniline. The result of elemental analysis of polyaniline is presented here.

关键词： Electrochemical polymerization Polyaniline Spectroelectrochemistry FTIR spectra elemental analysis

Dielectric and physico-chemical behavior of single thermally thick wood blocks under microwave assisted pyrolysis

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第3期86卷 291-303页

作者： Nicole Vorhauer-Huget Jakob Seidenbecher Supriya Bhaskaran Francesca Schenkel Lucas Briest Suresh Gopalkrishna Jan Barowski Andrea Dernbecher Liane Hilfert Ilona Rolfes Alba Dieguez-Alonso Otto von Guericke University Magdeburg Universitatsplatz 239106MagdeburgGermany Ruhr University Bochum Institute of Microwave SystemsUniversitatsstraβe 15044801BochumGermany

Pyrolysis of thermally thick beech wood blocks with a size of around 2.5×8×6 cm^(3)(width×length×height)was carried out in a lab scale microwave reactor with a frequency of 2.45 GHz,operated,both,at 300 W and 600 W under inert conditions,using N_(2) at around 400 mbar absolute *** microwave cavity had a size of 20×20×20 cm^(3).The specific energy supply referred to the untreated wood block was 4-8 W/g,with slight variations depending on the initial water *** mass loss and the reflected microwave power were in-situ monitored during the *** sample surface and chamber temperatures were measured with a pyrometer and a thermocouple,***-chemical and dielectric properties of the produced solids were investigated and compared to those of chars produced under conventional pyrolysis using the same raw *** is shown that the complex dielectric permittivity of the solid products changed drastically during the pyrolysis process,with increasing heating properties as the conversion process *** was easily achieved using 60o W without ***,300 W was not enough to achieve a high conversion degree,independently of the irradiation ***,together with the physico-chemical analyses of the solids,hinted to the importance of the transport kinetics in thermally thick materials,although further investigationis still required.

关键词： Microwave assistedpyrolysis Conventional pyrolysis Dielectric measurements Penetration depth elemental analysis