Application of backflush and micro-flow techniques to the analysis of C5—C13 hydrocarbons in crude oils and its geochemical significance

An Agilent 6890N GC equipped with both FID and Agilent 5975 MSD analyzer has been employed to analyze C₅—C₁₃ hydrocarbon fractions of crude oils. A technical combination of program temperature volatilizer injection, backflush and micro-flow controller afforded a fine separation of C₅—C₁₃ compounds on a PONA column with the heavy part of crude oils being cut off before entering the analytical column. Both GC-FID chromatogram and GC-MS mass chromatograms (MID and full scan) could be obtained at the same time. The retension time differences of nC₆—nC₁₃ alkanes between GC and TIC were in the range of 0.02—0.58 minutes. Totally 286 peaks have been assigned group compositions. Results on 8 typical oil samples from CNPC Key Laboratory Crude Oil Library showed that the characteristics of C₆—C₁₃ hydrocarbon group composition could be used in oil-oil correlation studies.     

Electrical conductivity of molten LiF-DyF3-Dy2O3-Cu2O system for Dy-Cu intermediate alloy production

Dy-Cu intermediate alloys have shown substantial potential in the field of magnetostrictive and magnetic refrigerant materials. Therefore, this study focused on investigating the electrical conductivity of molten-salt systems for the preparation of Dy-Cu alloys and on optimizing the corresponding operating parameters. The electrical conductivity of molten LiF-DyF₃-Dy₂O₃-Cu₂O systems was measured from 910 to 1030℃ using the continuously varying cell constant method. The dependencies of the LiF-DyF₃-Dy₂O₃-Cu₂O system conductivity on the melt composition and temperature were examined herein. The optimal operating conditions for Dy-Cu alloy production were determined via analyses of the electrical conductivity and activation energies for conductance, which were calculated using the Arrhenius equation. The conductivity of the molten system regularly increases with increasing temperature and decreases with increasing concentration of Dy₂O₃ or Cu₂O or both. The activation energy E_κ of the LiF-DyF₃-Dy₂O₃ and LiF-DyF₃-Cu₂O molten-salt systems increases with increasing Dy₂O₃ or Cu₂O content. The regression functions of conductance as a function of temperature (t) and the addition of Dy₂O₃ (W(Dy₂O₃)) and Cu₂O (W(Cu₂O)) can be expressed as κ=-2.08435 + 0.0068t-0.18929W(Dy₂O₃)-0.07918W(Cu₂O). The optimal electrolysis conditions for preparing the Dy-Cu alloy in LiF-DyF₃-Dy₂O₃-Cu₂O molten salt are determined to be 2.0wt% ≤ W(Dy₂O₃) + W(Cu₂O) ≤ 3.0wt% and W(Dy₂O₃):W(Cu₂O)=1:2 at 970 to 1000℃.     

Alkaline pressure oxidative leaching of bismuth-rich and arsenic-rich lead anode slime

A new alkaline pressure oxidative leaching process(with NaNO3 as the oxidant and NaOH as the alkaline reagent)is proposed herein to remove arsenic,antimony,and lead from bismuth-rich and arsenic-rich lead anode slime for bismuth,gold,and silver enrichment.The effects of the temperature,liquid-to-solid ratio,leaching time,and reagent concentration on the leaching ratios of arsenic,antimony,and lead were investigated to identify the optimum leaching conditions.The experimental results under optimized conditions indicate that the average leaching ratios of arsenic,antimony and lead are 95.36%,79.98%,63.08%,respectively.X-ray diffraction analysis indicated that the leaching residue is composed of Bi,Bi2O3,Pb2Sb2O7,and trace amounts of NaSb(OH)6.Arsenic,antimony,and lead are thus separated from lead anode slime as Na3AsO4·10H2O and Pb2Sb2O7.Scanning electron microscopy and energy-dispersive spectrometry imaging revealed that the samples undergo appreciable changes in their surface morphology during leaching and that the majority of arsenic,lead,and antimony is removed.X-ray photoelectron spectroscopy was used to demonstrate the variation in the valence states of the arsenic,lead,and antimony.The Pb(IV)and Sb(V)content was found to increase substantially with the addition of NaNO3.     

Selective flotation separation of andalusite and quartz and its mechanism

The separation of andalusite and quartz was investigated in the sodium oleate flotation system, and its mechanism was studied by solution chemical calculation, zeta-potential tests, Fourier transform infrared spectroscopic (FTIR), and X-ray photoelectron spectroscopic (XPS). The flotation tests results show that FeCl₃·6H₂O has a strong activation effect on andalusite and quartz and citric acid has a strong inhibitory effect on activated quartz, thus increasing the floatability difference between quartz and andalusite when the pulp pH is approximately 8. The FTIR, Zeta potential, and XPS analyses combined with the chemical calculation of flotation reagent solutions demonstrate that Fe forms hydroxide precipitates on the surface of andalusite and quartz and that oleate anions and metal ions adsorb onto the surface of the minerals. The elements Al and Fe can be chemically reacted. The anions in citric acid have different degrees of dissolution of Fe on the andalusite and quartz surfaces, thereby selectively eliminating the activation of the elemental Fe on andalusite and quartz and increasing the floatability of andalusite, leading to a better separation effect between andalusite and quartz.     

Interface microstructure and formation mechanism of ultrasonic spot welding for Al–Ti dissimilar metals

The present study focuses on interface microstructure and joint formation. AA6061 aluminum alloy (Al) and commercial pure ti-tanium (Ti) joints were welded by ultrasonic spot welding (USW). The welding energy was 1100–3200 J. The Al–Ti joint appearance and in-terface microstructure were observed mainly via optical microscopy and field emission scanning electron microscopy. Results indicated that a good joint can be achieved only with proper welding energy of 2150 J. No significant intermetallic compound (IMC) was found under all con-ditions. The high energy barriers of Al–Ti and difficulties in diffusion were the main reasons for the absence of IMC according to kinetic ana-lysis. The heat input is crucial for the material plastic flow and bonding area, which plays an important role in the joint formation.     

STUDY ON ELIMINATING FLUORESCENCE IN COTTON PULP WITH PERACETIC ACID

INTRODUCTIONIn resent years people have paid more and more attention to the elimination of fluorescence in cotton linter for the sake of getting better cotton linter pulp since some user ask for higher quality cotton pulp. Cotton linter is a kind of industrial material used to make fine paper, synthetic fiber, medicine additives and other chemical products. Some impurities containing fluorescence usually enter into linter during the processing and purchase, especially in the low grade of l…     

Artificial Neural Network Applied to Quality Diagnosis

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对《定冠词“the”的基本用法》一文的看法

学报1979年第一期发表了米景沅同志的《定冠词“the”的基本用法》一文。该论文叙述的语法基本规则及例句,多半取材于当前在我国外语教育界最流行的一些语法著作及有关辞书和材料。该文行文较长,谈得较细,并且列举了不少搜集来的例句进行说明解释,费了一定的功夫,是值得称许的。但读后觉得存在一些问题,特提出来和作者研讨。(1) 论文(54页)有这样一个句子:“He made a comparison between the English and German language.”我们查问了张道真的《实用英语语法》,该书39页上写着:He made a comparison between the English and the German languages.论文作者把German之前的定冠词“the”去掉,似乎欠妥;张道真在同一页上说:“当并列两个名词前都应有定冠词时,一般不能省略。”language一词如用单数,那么并列的English和German前一般应有各自的定冠词,因为在这种情况     

Vibrating Liquefaction Experiment and Mechanism Study in Saturated Granular Media

1IntroductionLiquefactionof saturatedgranules(e.g.brokenrocks,sandy soils and tailings,etc)is aphenomenon that granules show similar liquidcharacter and lose carrying capacity completelyunderthe actionof dynamical load[1-5].There aresome behaviors about liquefaction,such as theeruption of water and sands fromthe ground,theinstability of foundation,the large area landslip,the building falling by vibration,etc.Theproblemof liquefactionis aremarkable questioningeotechnical engineering.In the past…     

An effective absorbing boundary algorithm for acoustical wave propagator

In this paper,Berenger's perfectly matched layer(PML)absorbing boundary condition for electromagnetic waves is introduced as the truncation area of the computational domain to absorb one-dimensional acoustic wave for the scheme of acoustical wave propagator(AWP).To guarantee the efficiency of the AWP algorithm,a regulated propagator matrix is derived in the PML medium.Numerical simulations of a Gaussian wave packet propagating in one-dimensional duct are carried out to illustrate the efficiency of the combination of PML and AWP.Compared with the traditional smoothing truncation windows technique of AWP,this scheme shows high computational accuracy in absorbing acoustic wave when the acoustical wave arrives at the computational edges.Optimal coefficients of the PML configurations are also discussed.