Wyniki wyszukiwania - Biblioteka Nauki

1

Propagation of goldenrod (Solidago canadensis L.) from leaf and nodal explants

100%

Li J. , Kang Y. , Qiang S. , Peng G.

Acta Societatis Botanicorum Poloniae

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2012

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tom 81

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nr 1

EN

Goldenrod (Solidago canadensis L.) is an invasive plant species in many countries except North America but a cut-flower species worldwide. There is a need to generate and propagate goldenrod clones efficiently for research and commercial purposes. A callus induction and plantlet regeneration system was developed by studying the influence of explant type and different concentrations of plant growth regulators. The highest callus production from leaf segments was obtained on Murashige and Skoog's medium (MS medium) supplemented with 1.0 mg/L naphthalene acetic acid (NAA) and 1.0 mg/L 6-benzylaminopurine (BA). Adventitious shoots could be regenerated directly from leaf explants without an intermediate callus phase with the highest shoot induction percentage of 87.2%. The largest number of adventitious shoots per leaf explant (3.2) was obtained on MS medium supplemented with 0.4 mg/L NAA and 2.0 mg/L BA. MS medium supplemented with 0.1 mg/L NAA and 1.0 mg/L BA was the best medium for axillary shoot regeneration from nodal segments. The highest root number and longest roots occurred on half-strength MS without the addition of any growth regulator. Rooted plantlets were then transferred to a soil-based growth medium, placed in a greenhouse, and acclimatized with 100% success. All surviving plants grew normally without showing any morphological variation when compared to those grow from seed. This regeneration protocol may be used to produce certain biotypes of goldenrod suitable for genetic transformation, rapid propagation of goldenrod for commercial purposes or for screening fungi and toxins as potential biocontrol agents against this weed.

2

Voltage/current control mode for combined three-phase inverter

100%

Wang H. , Yue X. , Pei X. , Kang Y.

Przegląd Elektrotechniczny

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2010

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tom R. 86, nr 11a

358-362

EN

For parallel inverters system, controlling the output voltage in normal operation constantly is named the voltage control mode (VCM), and controlling the output current constantly in abnormal operation conditions (such as short circuit) is named the current control mode (CCM). The combined three-phase inverter topology is presented, the equivalent inverter topology with a LCL filter is obtained and mathematical models are built in VCM and CCM. A hybrid control strategy is proposed. The PID control and the repetitive control are used in VCM to obtain the fast dynamic responses and low harmonic distortions. On the other hand, the state feedback control is used in CCM. Pole assignment has been employed in designing parameter of the PID controller and state feedback, and the repetitive control design process is given. Experimental results validate the proposed control using two 400KVA parallel inverters.

PL

Dla równoległego systemu przekształtników zazwyczaj stosuje się system kontroli napięcia VCM i system kontroli prądu CCM (w warunkach specjalnych - np. zwarcia). Zaprezentowano topologie przekształtnika trójfazowego. Odpowiednia topologia przekształtnika z filtrem LCL została przedstawiona. Zaproponowano hybrydową strategię sterowania. System PID sterowania użyty w VCM zapewnia szybką odpowiedź dynamiczną i małe zniekształcenia. W układzie CCM użyto stałego sprzężenia zwrotnego. Sprawdzono położenie biegunów. Wyniki eksperymentu z dwoma 400kVA równoległymi przekształtnikami potwierdziły założenia.

3

A Dual Loop Control Strategy for Parallel Interleaved Three-Phase Four-Leg PWM Boost-Type Rectifier in UPS

100%

Lei H. , Xiao E. , Lin X. , Kang Y.

Przegląd Elektrotechniczny

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2012

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tom R. 88, nr 10a

242-246

EN

This paper presents a dual-loop control strategy for parallel interleaved three-phase four-leg PWM boost-type rectifier in double conversion UPS. The interleaving method is adopted for its main benefit of harmonic cancellation. The current in the fourth leg is treated as a perturbation because the fourth leg is shared by rectifier and inverter, and the controller can be designed in a-b-c coordinate conveniently. The DCbus voltage feedback in outer control loop can be delayed by quarter-cycle to filter out the oscillating component when the load of UPS is unbalanced. The performance of proposed control scheme is verified by experimental results.

PL

W artykule zaprezentowano strategię dwóch pętli sterowania trójfazowym czterogałęziowym prostownikiem PWM typu boost w układzie UPS. Wykorzystano metodę z przeplotem w celu eliminacji wpływu harmonicznych. (Dwuobwodowa strategia sterowania trójfazowym prostownikiem PWM w układach UPS)

4

A high acid mesoporous USY zeolite prepared by alumination

88%

Ma J. , Kang Y. , Ma N. , Hao W. , Wang Y.

Materials Science Poland

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2013

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tom Vol. 31, No. 1

19-24

EN

A high-acidity HUSY zeolite with mesoporous structure was prepared by alumination with a dilute aqueous NaAlO2 solution and characterized by XRD, N2 adsorption, IR framework vibration and 29Si MAS NMR methods. The results indicated the extra-framework aluminum was reinserted into the tetrahedral framework through isomorphic substitution of framework Si (0Al) sites by Al ions, whereas the crystal and micropore structure were unaltered. FTIR spectra of hydroxyl vibrations and pyridine adsorbed on realuminated zeolites showed that the number of Brfinsted acid sites and strong Lewis acid sites increased whereas weak Lewis acid sites decreased twice. The mesoporous structure composed of inter-and intra-crystalline pores in the aluminated HUSY increased the external surface area of the zeolite, improving accessibility of molecules to the active sites and enhancing its catalytic ability. The realuminated HUSY zeolite supported with Ru catalyst exhibited a higher catalytic activity for benzene hydrogenation than the parent HUSY zeolite; the reaction rate in comparison to the mesozeolite increased by 5.5 times.

5

An Improved Method for Voltage Sag Detection Based on Weighted Least-Squares Estimation with Harmonic Models

88%

Lei H. , Lin X. , Kang Y. , Duan Y. , Qiu J.

Przegląd Elektrotechniczny

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2012

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tom R. 88, nr 10a

238-241

EN

A rapid voltage sag detection method based on weighted least-squares estimation (WLSE) with harmonic models is proposed to satisfy the requirement of the dynamic voltage restorer. The covariance resetting technique is adopted to detect the voltage sag accurately and rapidly, even in condition the voltage contains considerable amount of harmonic components. The threshold of covariance resetting is larger than the steady state error between the sample and estimation of the voltage for the purpose of favorable covariance resetting only if the voltage sag occurs. The threshold of covariance resetting can be small because the steady state error will contain little harmonic components by the proposed WLSE method which have a positive impact on the detecting speed even if the depth of voltage sag is low. The algorithm has been tested under different conditions so as to verify its performance on voltage sag detection.

PL

Zaproponowano metodę szybkiej detekcji zapadu napięcia bazująca na określaniu średniej ważonej najmniejszych kwadratów. Do detekcji zapadu wykorzystuje się technikę kowariancji co umożliwia szybką detekcję nawet przy znacznej zawartości harmonicznych. (Ulepszona metoda detekcji zapadów napięcia bazująca na określaniu wartości ważonej najmniejszych kwadratów z uwzględnieniem harmonicznych)

6

Wild food plants and wild edible fungi of Heihe valley ( Qinling Mountains, Shaanxi, central China): herbophilia and indifference to fruits and mushrooms

88%

Kang Y. , Luczaj L. , Ye S. , Zhang S. , Kang J.

Acta Societatis Botanicorum Poloniae

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2012

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tom 81

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nr 4

7

How Chlorella sorokiniana and its high tolerance to Pb might be a potential Pb biosorbent

75%

Liang S. , Kang Y. , Zeng L. , Qin Y. , Wang L. , Zhang Q. , Luo J.

Polish Journal of Environmental Studies

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2017

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tom 26

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nr 3

EN

The link between the acute toxicity of heavy metals on algae and the bioadsorption capacity of heavy metals by algae has seldom been reported. In the present study, an acute toxicity experiment was carried out to assess the toxic effects of Pb, Cu, and Cd for Chlorella sorokiniana, and the 96 h IC₅₀ values were 0.249 mg/L, 0.485 mg/L, 46.108 mg/L, and 21.00 mg/L for Cu, Cd, Pb (total), and Pb (free ion), respectively, which implied that Chlorella sorokiniana showed high tolerance to Pb compared to Cu and Cd. Pb distribution analysis indicated that 73.40% to 98.15% of free Pb ions were accumulated on the algae cell wall to avoid further intracellular accumulation, resulting in irreversible metabolic disorders. Then the adsorption capacity of Chlorella was explored. It could be found that the Langmuir model (the R² were 0.988 and 0.962 for living and lifelss cells, respectively) was fit to explain the adsorption equilibrium data and the qₑ calculated by this model were 1.54 and 2.97 mg /10¹⁰ cells for living and lifeless cells, respectively, which was consistent with the experimental result. In the competitive adsorption, Chlorella exhibited a greater affinity for Pb with the higher removal rate compared to Cu and Ni. Therefore, the renewable Chlorella sorokiniana and its dramatic resistance to Pb may serve as a potential biosorbent for Pb in the future.