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1

Simulation and Casting Process of Aluminum Alloy Multi-Way Valve Body with Various Gating Systems

Rong L., Lunjun C., Ming S., Qi Z., Yong L., Heng W.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

84--94

EN

In order to study the effects of various gating systems on the casting of a complex aluminum alloyed multi-way valve body, both software simulation analysis and optimization were carried out. Following, the aluminum alloyed multi-way valve body was cast to check the pouring of the aluminum alloy valve body. The computer simulation results demonstrated that compared to the single side casting mode, the casting method of both sides of the gating system would reduce the filling of the external gas, while the air contact time would be lower. Adversely, due to the pouring on both sides, the melt cannot reach at the same time, leading to the liquid metal speed into the cavity to differ, which affected the liquid metal filling stability. The riser unreasonable setting led to the solidification time extension, resulting in a high amount of casting defects during solidification. Also, both gating systems led the entire casting inconsequential solidification. To overcome the latter problems, a straight gate was set at the middle pouring and the horizontal gate diversion occurred on both sides of pouring, which could provide better casting results for the aluminum alloyed multi-valve body.

2

Study on Friction and Wear Characteristics of Aluminum Alloy Hydraulic Valve Body and Its Antiwear Mechanism

Rong L., Lunjun Ch., Ming Su, Qi Z., Yong Liu

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

207--215

EN

In order for the working status of the aluminum alloyed hydraulic valve body to be controlled in actual conditions, a new friction and wear design device was designed for the cast iron and aluminum alloyed valve bodies comparison under the same conditions. The results displayed that: (1) The oil leakage of the aluminum alloyed hydraulic valve body was higher than the corresponding oil leakage of the iron body during the initial running stage. Besides during a later running stage, the oil leakage of the aluminum alloyed body was lower than corresponding oil leakage of the iron body; (2) The actual oil leakage of different materials consisted of two parts: the foundation leakage that was the leakage of the valve without wear and wear leakage that was caused by the worn valve body; (3) The aluminum alloyed valve could rely on the dust filling furrow and melting mechanism that led the body surface to retain dynamic balance, resulting in the valve leakage preservation at a low level. The aluminum alloy modified valve body can meet the requirements of hydraulic leakage under pressure, possibly constituting this alloy suitable for hydraulic valve body manufacturing.

3

Investigation of the Influence of electrical parameters on dynamic property of Self-integrating Rogowski coil

Rong L., Ji-sheng L., Yang-yu F.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 4

115-119

EN

Rogowski coil as the special mutual inductor is often applied to measure high amplitude and transient currents in electrical industry. Since there are no iron core, they cannot be driven into saturation. In this paper, the transfer function of the self-integrating Rogowski is proposed based on the analysis of the Rogowski coil. According to the transfer function, bode diagram simulates the effect of changing some of these parameters. Also, the influences of self-inductance, sampling resistance and stray capacitance are disussed in details. Moreover, a high-frequency current transducer for measurement of PD is developed based on the self-integrating Rogowsk,and the actual dynamic response are performed by adopting function generator. Based on the transducer, measurements of PD of needle-plate model under impulse voltage is identical to the results of theory analysis. Finally, the method to obtain an optimum dynamic property in self-integrating Rogowski coil is suggested.

PL

W artykule wyznaczono charakterystykę przetwarzania paska Rogowskiego bez układu całkującego. Wyznaczono charakterystyki częstotliwościowe czujnika prądu a następnie sprawdzono parametry na przykładzie badania wyładowań niezupełnych.

4

Determination of free 3-nitrotyrosine in human plasma using HPLC method with fluorescence detection

Guo S., Shao L., Pei J., Rong L., Wang X., Chi D.

Chemia Analityczna

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2009

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Vol. 54, No. 4

691-703

EN

High performance liquid chromatography assay for determination of free 3-nitrotyrosine in human plasma was developed. After precipitation of plasma proteins and solid phase extraction of 500 μL-in-volume plasma sample, derivatization reaction between 3-nitrotyrosine and 4-fiuoro-7-nitrobenzofurazon was carried out under alkaline conditions (pH 9.5). A 20μL aliquot of the reaction mixture was injected directly into a HPLC appa ratus using acetonitrile-phosphate buffer (0.02 mol L-1, plus 500 μ L-1TFA, pH 3.0) (36:64, v/v) mobile phase at a flow rate of 1.0 mL min-1. Separation was performed on C18 column at 35°C. Analytical signals were obtained using a fluorescence detector at excitation and emission wavelengths of 470 nm and 530 nm, respectively. Calibration plot was linear over the analyte concentration range in plasma 0.5-50.0 nmol L-1. Limit of detection was 0.15 nmol L-1. Intra- and inter-day variation coefficients were lower than 6.4% and 7.2%, respectively. The proposed method was sensitive, accurate, and reproducible; it allowed for determination of 3-nitrotyrosine in human plasma at a nanomolar level. It was successfully applied to the determination of 3-nitrotyrosine in plasma of healthy volunteers and patients with chronic hepatitis B.

PL

Opracowano metodę analityczną opartą na wysokosprawnej chromatografii do oznaczania wolnej 3-nitrotyrozyny w osoczu ludzkim. Po wytrąceniu białek i ekstrakcji (stała faza) z próbki plazmy o objętości 500 μ L modyfikowano chemicznie 3-nitrotyrozynę w reakcji z 4-fluoro-7-nitrobenzofurazonem przy pH 9,5.2 L końcowego roztworu wstrzykiwano do kolumny z ruchomą fazą o składzie acetonitryl-bufor fosforanowy o pH 3,0 (36:64 v/v) i szybkości przepływu l ,0 mL min-1. Do rozdzielania używano kolumny C18 w temperaturze 35°C. Fluorescencyjny detektor pracował przy długościach fali 471 (wzbudzenie) i 530 nm (emisja). Krzywa kalibrowania była liniowa w zakresie stężeń 0,5-50,0 nmol LL-1. Granica wykrywalności wyniosła 0,15 nmol L-1. Współczynniki zmienności w ciągu dnia i miedzy-dniowe były odpowiednio niższe niż 6,4 i 7,2%. Opracowana metoda jest czuła, dokładna i odtwarzalna; pozwoliła na oznaczenie 3-nitrotyrozyny w osoczu na poziomie nanomolo-wym. Badano poziom tego związku u zdrowych ochotników i pacjentów z chronicznym zapaleniem wątroby.