共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
3.
用液膜法从稀土浸出液中分离非稀土杂质 总被引:1,自引:0,他引:1
探讨了用乳状液膜从浸出的稀土液中提取稀土的可能性;研究了流动载体、料液类型、无机盐、表面活性剂、水乳比、NaAc缓冲剂和膜回用等对乳状液膜提取稀土中浓缩和分离非稀土杂质(Ca、Mg、Zn、Fe、Pb、Al、Cu、Na)的影响,结果表明:采用该技术稀土提取率达85%~97%、富集液中稀土的浓度在40~90g/L、稀土氧化物的纯度达99%以上;比较了乳状液膜法和现行工业法所得稀土氧化物的分析结果,结果 相似文献
4.
5.
T Yoshida 《Canadian Metallurgical Quarterly》1997,69(15):3038-3043
A new method is established for separating peptides in normal phase liquid chromatography using TSK gel Amide-80, carbamoyl groups bonded to a silica gel matrix, and an acetonitrile-water solution containing 0.1% trifluoroacetic acid. Peptide retention time increased with acetonitrile concentration in the initial eluent. Hydrophilic peptides with no retention in a reversed phase column were retained and separated in the present method. Separation selectivities in the present and reversed phase methods differed significantly. Two-dimensional separation of protein digest using reversed and normal phases was conducted, taking advantage of the differences in selectivities. All peptides obtained from the digest could be separated completely. The present method is useful for separating peptide mixtures in conjunction with reversed phase liquid chromatography. Peptide recovery from the Amide-80 column exceeded 80%, as with the reversed phase column, and repeatability and reproducibility were satisfactory. 相似文献
6.
7.
8.
9.
It was found that both normal human myometrium and uterine leiomyoma contain several glycosaminoglycans. In contrast to many normal and tumour tissues the amount of hyaluronic acid is very low and the proportional amount of sulphated glycosaminoglycans is distinctly higher. It is of interest that heparan sulphate is the major glycosaminoglycan component both in normal myometrium, and in leiomyoma. The amount of hyaluronic acid in myometrium and in the leiomyoma is very low. No significant change in hyaluronate content was observed during the tumour growth. In contrast to that the amount of some sulphated glycosaminoglycans (heparan sulphate, keratan sulphate, chondroitin sulphates and heparin) distinctly increased. It is suggested that some of the GAGs participate in the creation of a storage depot for biologically active molecules (growth factors, enzymes) which are thereby stabilized and protected. Hydrolytic degradation of some GAGs may result in the release of some cytokines which may promote the tumour growth and stimulate collagen biosynthesis by tumour cells. 相似文献
10.
Cloned gene 8, which specifies the protein of the head-tail connector of bacteriophage T7, was expressed in Escherichia coli. Extracts prepared in a low-salt buffer gave rise to free monomers, assembled connectors, and various complexes and aggregates. Connectors isolated as single peaks from DEAE-Sepharose and phosphocellulose chromatography gave separate peaks of monomers and stable connectors upon hydroxylapatite chromatography perhaps because of dissociation of monomer-connector complexes or disassembly of unstable connectors. Electron microscopy showed that the connectors readily formed ordered arrays after hydroxylapatite chromatography but not before. Addition of 100 mM NaCl to the buffer used to prepare extracts eliminated most complexes and aggregates and gave rise almost entirely to monomers and stable connectors that formed arrays even before hydroxylapatite chromatography. The distribution of masses determined by scanning transmission electron microscopy would be consistent with a mixed population of stable connectors containing 12 or 13 monomers, and the same preparation gave two bands upon agarose gel electrophoresis. Connectors bound linear, circular and supercoiled DNA, whereas monomers did not, as determined by a gel-shift assay. No ATPase activity was detected in either monomer or connector preparations in the absence or presence of DNA. 相似文献
11.
K Harada M Oshikata T Shimada A Nagata N Ishikawa M Suzuki F Kondo M Shimizu S Yamada 《Canadian Metallurgical Quarterly》1997,5(5):201-207
Microcystins are potent hepatotoxins produced by cyanobacteria, and are also tumor promoters as well as potent inhibitors of the catalytic subunits of protein phosphatases 1 and 2A. In order to establish a physicochemical method for individual detection and determination of trace amounts of microcystins, we developed a derivatization method for fluorescence (FL) and chemiluminescence (CL) detection, in which a highly fluorescent dienophile, DMEQ-TAD (4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalinyl) ethyl]-1,2,4-triazoline-3,5-dione), was used as the labeling reagent. DMEQ-TAD reacted smoothly with the conjugated diene of the Adda moiety to give 2 stereoisomers of the adducts. As a result of the extensive experiments, the following reaction conditions were optimized for the labeling: sample amount, 10 micrograms; reaction solvent, DMF:acetonitrile (1:1); reaction time, 15 minutes; reaction temperature, 70 degrees C; amount of DMEQ-TAD used relative to that of microcystin, 80 equivalent. The resulting 6 adducts from microcystins-LR, -YR, and -RR can be separated from one another using the following reversed phase HPLC conditions in combination with a clean-up using ODS silica gel: column, Cosmosil 5C18-AR (150 x 4.6 I.D. mm); mobile phase, methanol:0.05M phosphate buffer (pH 3) (1:1); flow rate, 1.0 ml/min; detection, FL lambda ex 370 nm, lambda em 440 nm. The detection limits of the DMEQ-TAD derivatives were estimated to be 100 and 500 pg for LR, and 65 and 2,500 pg for RR using FL and CL detections, respectively; and the detection behavior was different from that of the Dns-Cys derivatives, which were more sensitive to CL than FL. 相似文献
12.
Hyo-Hoon Park Seong-Jai Cho Duk N. Yoon 《Metallurgical and Materials Transactions A》1984,15(6):1075-1080
Models for liquid flow into isolated pores during liquid phase sintering are described qualitatively. The grains are assumed
to maintain an equilibrium shape determined by a balance between their tendency to become spherical and a negative capillary
pressure in the liquid due to menisci at the specimen surface and the pore. With an increase of grain size, the grain sphering
force decreases while the radius of liquid menisci increases to maintain the force equilibrium. When grain growth reaches
a critical point, the liquid menisci around a pore become spherical and the driving force for filling the pore rapidly increases
as liquid flows into it. The critical grain size required for filling a pore increases linearly with pore size. Experimentally,
filling of isolated pores has been investigated in Fe-Cu powder mixture after liquid phase sintering treatment and after dipping
into a molten matrix alloy. The observed pore filling behaviors agree with the qualitative predictions based on the models.
In Fe-Cu alloy, pore filling is terminated by gas bubbles formed in liquid pockets.
This paper is based on a presentation delivered at the symposium “Activated and Liquid Phase Sintering of Refractory Metals
and Their Compounds” held at the annual meeting of the AIME in Atlanta, Georgia on March 9, 1983, under the sponsorship of
the TMS Refractory Metals Committee of AIME. 相似文献
13.
14.
A right lung cancer case is presented, aged 65 years, obese, submitted to a right lung resection. Stress is laid on the difficult evolution concerning the haemodynamics and particularly the breathing owing to the association of risk factors. 相似文献
15.
16.
《中国稀土学报(英文版)》2017,(2)
This paper reviewed various systems such as neutral phosphorus and acid phosphorus, carboxylic acid and amine extractant for solvent extraction chemistry of yttrium, including thermodynamics, kinetics and yttrium extracting separation process containing the development course and new separation process. 相似文献
17.
EJ Murphy AP Slivka TA Rosenberger LA Horrocks 《Canadian Metallurgical Quarterly》1993,209(2):339-342
A sensitive, reliable method for the extraction, separation, and quantitation of methylprednisolone from rat brain is reported. The method can accurately quantitate methylprednisolone levels between 9.8 and 2500 ng/injection using a two-step HPLC separation and monitoring absorbance at 254 nm. A 90% extraction recovery of methylprednisolone (interday variation of 9.0% and an intraday variation of 0.0 to 7.7%) from rat cortex was obtained with a double extraction method using low toxicity solvents. These solvents are known to quantitatively extract the neutral lipids and phospholipids from brain. Combined with the ability to separate the neutral lipid and methylprednisolone fractions for further separation, and the ability to separate all phospholipid classes in the first run, this method offers great utility combined with the reliable, high extraction recovery and sensitive quantitation of methylprednisolone. 相似文献
18.
Over a hundred acidic urinary constituents were separated within 30 min by using 5-micron octadecyl-silica columns and gradient elution with increasing acetonitrile concentration in dilute aqueous phosphoric acid solution at 70 degrees. The column effluent was monitored with a UV detector at 280 nm or with a fluorescence detector at 260 nm excitation and 340 nm emission wavelengths. The high sensitivity and speed of analysis, the excellent reproducibility and adequate resolution obtained suggest that this technique may be useful to obtain metabolic profiles in routine clinical work. 相似文献
19.
20.
Results of an investigation into a new method of magnetic liquid separation, which differs from known ones by the presence of a bilayer separation medium in the form of immiscible ferromagnetic liquids of different densities, are presented. During the separation in a bilayer medium, the equilibrium condition of a particle on a flat surface, which is written according to the Young law and Neumann rule, should be supplemented by the linear tension of a curve-phase interface surface. The linear tension is the force and energy barrier, which prevents fastening of small particles of precious metals at the phase interface, and the cause of their effective separation into a heavy fraction. The method of magnetic liquid separation is tested for concentrates containing platinum group metals. It is established that, during the separation in the bilayer medium, the recovery of platinum group metals into the heavy fraction is 25.89%, while that for the waterbased ferromagnetic liquid is 19.73%. The quality of the heavy fraction makes gives the opportunity to direct it to the hydrometallurgical stage bypassing the copper plant, which increases the recovery of precious metals by 5.0 abs %. 相似文献