Wyniki wyszukiwania - BazTech

1

Mineralogical and chemical characteristics of the lead-zinc tailing and contaminated soil from the mine tailing pond in Hunan Province (China)

Li C., Zeng L., Fu J., Chen J., He J., He Z.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

1133--1147

EN

The mineralogical and chemical characteristics of heavy metals in tailings and soils is an imperative for potential ecological risk assessment of metals to environment and heavy metals pollution prevention and control. The lead-zinc tailing and contaminated soil in and near the tailing pond were sampeled from a mine tailing pond in Hunan province (China), in which the chemical composition, phase composition and thermal behavior of tailing and soil were investigated. Furthermore, the petrography of lead-zinc tailing and chemical fractionations of Pb and Zn in the contaminated soil were studied in details. The mineral phases of lead-zinc tailing were galena, pyrite, chalcopyrite, sphalerite, quartz and fluorite, as distinguished by the reflected light microscopy and further proofed by the scanning electron microscope-energy dispersive spectrometer under the back scattered electron mode. Chemical fractionations were carried out by the European Community Bureau of Reference (BCR) sequential extraction procedure for Pb and Zn in the soil and the mild acido-soluble (F1), reducible (F2), oxidizable (F3), and residual (F4) fractions were 5.90, 75.24, 4.90 and 13.96% for Pb, and 47.74, 34.06, 9.59 and 8.61% for Zn, respectively. Subsequently, the individual contamination factor (ICF) of Pb and Zn were calculated as 6.16 and 10.61, respectively. The DTPA-available content of Pb and Zn in the contaminated soil were 39.9 and 170.7 mg·kg-1, respectively. The study provided a base for selecting remediation strategies in the studied area.

2

Study of Magnetic Levitation Spherical Joint with Decoupling Control

Zhang F., Zeng L., Fang C.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 7b

239--242

EN

This paper presents a new magnetic levitation spherical reluctance driving joint. After the analysis of air-gap magnetic theory of the driving joint and the working mechanism of the magnetic levitation force and electromagnetic torque, its mathematical model and the inverse system decoupling model have been established. The decoupling linearization and the state feedback closed-loop control system have been achieved also. The result of system simulation provides us the decoupling characteristic and the dynamic characteristic of the driving joint system.

PL

W artykule zaprezentowano reluktancyjne połaczenie kuliste z lewitacja magnetyczną. Zaprezentowano model matematyczny i odwrotny model odsprzężenia. Przeanalizowano układ ze statycznym sprzężeniem zwrotnym.

3

Force and torque study of magnetic levitation spherical driving joint with magnetic field segmentation method

Zeng L., Zhang F., Zhang D.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 7b

235--238

EN

This paper presents a novel multi-degree-of-freedom spherical reluctance driving joint with magnetic levitation. The analysis of operation mechanism and the joint’s magnetic conduction of the gap are deduced by means of the way to magnetic segmentation. The relationship between electrical and mechanical energy conversion is analysed and then the radial suspension force and the tangential suspension torque are calculated. The simulation experiments show that the system of driving joint has well static and dynamic characteristics.

PL

W artykule zaprezentowano kuliste reluktancyjne połączenie napędowe o wielu stopniach swobody. Przeanalizowano właściwości bazując na magnetycznej segmentacji. Obliczono promieniową siłę i tangencjalny moment.

4

An isocratic UV HPLC assay for analysis of total and free melphalan concentrations in human plasma

Nath C. E., Zeng L., Eslick A., Trotman J., Earl W.

Acta Chromatographica

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2008

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Vol. 20, no. 3

383-398

EN

A simple isocratic HPLC-UV assay for measurement of total and free melphalan concentrations in human plasma is described. Samples were prepared by methanol precipitation (total melphalan assay) and ultrafiltration (free melphalan assay). On a 25 cm × 4.6 mm C column with 0.016 M mixed soldium phosphate citrate buffer (pH 3.75)-acetonitrile 87:13 as mobile phase, at a flow rate of 1 mL min -1, the retention time of melphalan was 11.5 min. Detection was at 254 nm. For total melphalan assay response was a linear function of concentration up to 40 µg mL -1, with excellent interday precision (<6% for 0.5-40 µg mL -1 melphalan), accuracy (<2% deviation from the true concentration), and recovery (91-110%). For free melphalan assay response was a linear function of concentration up to 2.5 ?g mL -1, with good precision (<11% for 0.7-2.5 µg mL -1 melphalan) and recovery (89-93%). Detection limits were 0.1 µg mL -1 and 0.05 µg mL -1 for total and free melphalan assays, respectively. The assays were clinically applied in a study of myeloma patients.