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1

The influence of finite element meshing accuracy on a welding machine for offshore platform’s modal analysis

Xie J., Sun D., Xu C., Wu J.

Polish Maritime Research

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2018

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S 3

147--153

EN

The purpose objective of this study was to investigate the influence of finite element meshing accuracy on modal analysis which is one of the basic factors affecting the accuracy of finite element analysis and mostly preoccupies the working staff in pre-processing finite element simulation models. In this paper, we established several finite element models of a welding machine for offshore platform, with the meshing accuracy as the variable and workbench software as the platform for modal analysis, as the same time, comparing the analysis results. The results indicated that for some specific structures and simulation types, mesh refinement alone does not achieve desired results, and the authors indicate that mesh refinement is rarely related to the equipment’s low-frequency modal analysis but it’s great related to the equipment’s high-frequency modal analysis. The findings of this study may serve as breaking the opinion that smaller mesh size means higher calculation precision and provides references for mesh division practices in low frequency modal analysis.

2

Low to middle vibro-acoustic noise prediction in ship cabin by using plate-cavity coupling model

Zhou Z., Wu J.

Polish Maritime Research

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2018

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S 2

149--157

EN

A plate-cavity coupling method based on modal expansion technique in the closed sound cavity was introduced, aiming at ship cabin structural noise. Using this method, a coupled equation was established. The structural vibration acceleration of the target cabin was extracted from a ship vibration response calculation, applied to the model. Then the target cabin noise value was obtained through numerical calculation. The effectiveness and reliability of the method were validated through experiments. The coupled model predicts noise in the cabin does not require fluid finite element model of the cabin air, thus greatly reducing the calculation time compared with the pure finite element method. It was shown that the method is suitable for the calculation of noise in a single ship cabin; the method has a high calculation efficiency. Furthermore, the calculated result is a continuum. On the one hand, it can be conveniently converted to an octave or 1/3 octave according to the specification. On the other hand, the form of the continuum also provides a corresponding response to the subsequent vibration and noise control.

3

Contribution on fluid inclusion abundance to activation of quartz flotation

Yuan Y., Zhang L., Guan J., Zhang C., Wu J., Chen Z.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

981--991

EN

In this study, comparative experiments were conducted on the recovery of quartz using flotation with different fluid inclusion abundances. A large number of fluid inclusions with various sizes have been found in natural quartz. Micrographs, inductively coupled plasma, electron probe microanalysis, homogenization temperature, Raman spectra, zeta potentials, X-ray photoelectron spectroscopy, scanning electron microscope, and energy dispersive spectrometer were used to characterize the fluid inclusions and quartz, as well as the adsorption tests and single mineral flotation experiments to investigate its floatability. The results demonstrated that it was more likely for quartz with higher fluid inclusion abundance to connect with Fe3+ sufficiently to achieve a high level of flotation recovery, due to the powerful collecting ability by sodium dodecyl sulphonate to Fe3+. Furthermore, the mechanism indicated that the adsorption between quartz and Fe3+ was a process of chemisorption.

4

Magnified holographic projection based on spatial light modulators

Su Y., Cai Z., Shi L., Zhou F., Chen H., Wu J.

Optica Applicata

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2018

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Vol. 48, nr 4

589--600

EN

In this paper, a magnified holographic projection based on spatial light modulators is proposed and implemented by combining four magnification methods, including similarity principle of Fourier transform, spatial division, digital lens, and image splicing methods. The Fourier holographic display system is constructed for the experimental verification of the proposed methods. With such four methods of holographic magnification, the reconstruction image can be magnified to 10 × 5 times in two-dimensional directions, which is verified by the experiments. Furthermore, the undesirable light of holographic projection is eliminated by encoding the linear phase onto the computer-generated holograms. The experimental results prove that the proposed system can realize magnified holographic projection with good reconstructed quality, which provides a promising potential for the dynamic holographic projector.

5

Estimation of small uav position and attitude with reliable in-flight initial alignment for MEMS inertial sensors

Wang D., Dong Y., Li Q., Wu J., Wen Y.

Metrology and Measurement Systems

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2018

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Vol. 25, nr 3

603--616

EN

The advance of MEMS-based inertial sensors successfully expands their applications to small unmanned aerial vehicles (UAV), thus resulting in the challenge of reliable and accurate in-flight alignment for air-borne MEMS-based inertial navigation system (INS). In order to strengthen the rapid response capability for UAVs, this paper proposes a robust in-flight alignment scheme for airborne MEMS-INS aided by global navigation satellite system (GNSS). Aggravated by noisy MEMS sensors and complicated flight dynamics, a rotation-vector-based attitude determination method is devised to tackle the in-flight coarse alignment problem, and the technique of innovation-based robust Kalman filtering is used to handle the adverse impacts of measurement outliers in GNSS solutions. The results of flight test have indicated that the proposed alignment approach can accomplish accurate and reliable in-flight alignment in cases of measurement outliers, which has a significant performance improvement compared with its traditional counterparts.

6

Performance optimization of organic Rankine cycles for waste heat recovery for a large diesel engine

Ma Z., Wu J., Zhang Y.

Archives of Thermodynamics

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2018

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Vol. 39, no 1

3--23

EN

In order to recover the low grade waste heat and increase system fuel economy for main engine 10S90ME-C9.2-TII(part load, exhaust gas bypass) installed on a 10000 TEU container ship, a non-cogeneration and single-pressure type of waste heat recovery system based on organic Rankine cycle is proposed. Organic compound candidates appropriate to the system are analyzed and selected. Thermodynamic model of the whole system and thermoeconomic optimization are performed. The saturated organic compound vapor mass flow rate, net electric power output, pinch point, thermal efficiency and exergy efficiency varied with different evaporating temperature are thermodynamically analyzed. The results of thermodynamic and thermoeconomic optimization indicate that the most appropriate organic compound candidate is R141b due to its highest exergy efficiency, biggest unit cost benefit and shortest payback time.

7

Parametric study on cement treated aggregate panel under impact load

Ali S., Liu X., Thambiratnam D., Fawzia S., Gu Y., Wu J., Remennikov A.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 2

622--629

EN

The cement treated aggregate (CTA) is increasingly used as base or sub-base layer for pavement to withstand various traffic and dynamic loads. Under extreme events, the CTA layer of the pavement is expected to absorb significant amount of impact energies subjected to different loading conditions including accidents, mobile vehicles, heavy aircrafts, machinery, or even terrorist attack. However, no research has been found on the resistance of CTA under drop weight impact load. To fill up this gap, a detailed study was carried out to investigate the impact resistance of CTA under impact loading through both experimental and finite element analysis (FEA). Moreover, detailed parametric studies were carried out based on the validated model to determine the significance of selected key parameters on the impact resistance of CTA.

8

Dual reference beam digital off-axis holography for exact suppression of zero-order term and twin image without spectrum loss

Wang M., Wang K., Zheng M., Li F., Wu J.

Optica Applicata

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2017

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Vol. 47, nr 3

435--443

EN

In this paper, we describe an effective approach to suppressing zero-order term and twin image by using pixel-by-pixel multiplication of double holograms in digital off-axis holography. This method records two holograms, respectively, by using the reference waves in different directions. It shows not only a simpler algorithm and easier implementation in experiment, but also exact and complete suppression of the zero-order term and twin image without any spectrum loss of the object in the image reconstruction, particularly when the image and the zero-order term are fairly close to each other. The experimental result approves of the theoretical prediction very well. This approach provides an effective solution to suppressing undesired noises in the digital off-axis holography.

9

Temperature-dependent Shock Initiation of CL-20-based High Explosives

Pi Z., Chen L., Wu J.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 2

361--374

EN

To investigate the effects of temperature on the shock initiation characteristics of hexanitrohexaazaisowurtzitane (CL-20), shock initiation experiments on heated C-1 explosive (94% epsilon phase CL-20, and 6% binder, by weight) were performed at temperatures of 20 °C, 48 °C, 75 °C, 95 °C, 125 °C, 142 °C, and 175 °C. An explosive driven flyer device was used to initiate the C-1 charges and manganin pressure gauges were embedded in the C-1 specimen to record the pressure changes with time. Our results show that C-1 becomes more sensitive as the temperature is increased from 20 °C to 95 °C. The ε to γ phase transition in CL-20 occurs at 125 °C; C-1 with CL-20 in the γ phase at 142 °C is less shock sensitive than C-1 with CL-20 in the ε phase at 95 °C or 75 °C. Compared with C-1 at 142 °C, C-1 at 175 °C shows a dramatic increase in shock sensitivity. An ignition and growth reactive flow model was used to simulate the shock initiation of C-1 at various temperatures, and the parameters were obtained by fitting the experimental data. With this parameter set, the shock initiation characteristics of C-1 for temperatures between 20 °C and 175 °C can be derived.

10

Detonation Reaction Characteristics for CL-20 and CL-20-based Aluminized Mixed Explosives

Liu D., Chen L., Wang C., Wu J.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 3

573--588

EN

The interfacial particle velocities for CL-20 and CL-20-based aluminized mixed explosives were measured by interferometry in order to analyze the aluminum reactions in the latter. The reaction characteristics were obtained, as well as a better understanding of the effects of aluminum powder on the detonation reaction zone length. Two functions were used to fit the particle velocity-time profiles, and their intersection was the corresponding Chapman-Jouget (CJ) point. From these profiles, the detonation reaction zone length and the aluminum reaction were then analyzed. CL-20-based explosives have a short reaction time (48 ns for a high CL-20 content), while the reaction time of CL-20/Al explosives increased with the aluminum content and particle size. Micron-scale aluminum particles barely reacted in the CL-20 detonation reaction zone, but instead reacted with the detonation products after the CJ point. This reduced the detonation pressure; however, the aluminum reaction can slow down the decrease in particle velocities. The start times of small-particle aluminum reactions were earlier than those of the larger particles. The 2-3-μm aluminum particles start to react within 1 μs after the CJ point, while the 200-nm particles may start to react in the reaction zone.

11

Eddy current density asymmetric distribution of damper bars in bulb tubular turbine generator

Qiu H., Fan X., Yi R., Feng J., Wu J., YANG C., ZHAO H.

Archives of Electrical Engineering

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2017

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Vol. 66, nr 3

571--581

EN

The major reasons that cause the damage of damper bars in the leeward side are found in this paper. It provides a route for the structure optimization design of a hydro generator. Firstly, capacity of a 24 MW bulb tubular turbine generator is taken as an example in this paper. The transient electromagnetic field model is established, and the correctness of the model is verified by the comparison of experimental results and simulation data. Secondly, when the generator is operated at rated condition, the eddy current density distributions of damper bars are studied. And the asymmetric phenomenon of the eddy current density on damper bars is discovered. The change laws of the eddy currents in damper bars are determined through further analysis. Thirdly, through the study of eddy current distributions under different conditions, it is confirmed that the stator slots and armature reaction are the main factors to affect the asymmetric distribution of the eddy current in damper bars. Finally, the studies of the magnetic density distribution and theoretical analysis revealed the asymmetric distribution mechanism of eddy current density.

12

Assessing the Suitability of Habitat for Wintering Siberian Cranes (Leucogeranus leucogeranus) at Different Water Levels in Poyang Lake Area, China

Chen B., Cui P., Xu H., Lu X., Lei J., Wu Y., Shao M., Ding H., Wu J., Cao M., Liu G.

Polish Journal of Ecology

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2016

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Vol. 64, nr 1

84--97

EN

Poyang lake area (1000–3246 km2) is the most important wintering ground for the globally critically endangered Siberian crane (Leucogeranus leucogeranus). More than 98% of the Siberian crane population overwinters in Poyang lake area. Remote-sensing and the spatial analysis tools of geographic information system (GIS) technology were used to assess the suitability of the habitat for wintering Siberian cranes in Poyang lake area at different water levels. The results demonstrated that as the water level increased within the range of 7.93–12.16 m, the area of unsuitable habitat increased gradually, but the areas of good, fair and poor habitat decreased. When the water level reached 12.16 m, good habitat for Siberian cranes covered an area of only 3005 ha, which is only 0.93% of the area of the total lake area. When human disturbance factors including vehicles, fishing and construction activities were added to the analysis of the current distribution of Siberian crane habitat, the results again indicated that the area of good habitat decreased with an increase in water level within the range of 7.93–12.16 m. Additionally, the areas of good habitat occurred primarily in the region of two national nature reserves, which are the Poyang Lake National Nature Reserve and the Nanjishan National Nature Reserve. Our study provides important data and an important theoretical basis for water level management and nature reserve construction in Poyang lake area.

13

Training safely, Training safety

Wu J., An M., Jin Y., Geng H.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2014

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Vol. 8, no. 3

423--427

EN

It is the basic requirement of maritime safety education to guarantee the safety of teaching operation while training the crew's occupation safety capability. Marine Training Center of Shanghai Maritime University has undertaken the practical teaching of "marine survival" for many years and come up with the whole safety procedures of training. Based on the requirements of SOLAS convention and regulations of STCW over crew training, this paper introduces the safety allocation, utilization and maintenance of teaching equipments. Through the investigation of the safety situation of students' practical operation, the safety teaching method named "four in one" has been put forward, which includes the pre-teaching safety precaution, the whole monitor during the teaching process, the post-teaching summary evaluation, and the reset and standby of teaching facilities. Finally, during the learning and training of "marine survival", crews and students are called on to place priority on personal safety rather than acquisition of knowledge and skills. Only in this way can they be capable of self-protection and protection of others in the career of seafaring.

14

Effectiveness Evaluation on Fire Drills for Emergency and PSC Inspections on Board

Wu J., Jin Y., Fu J.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2014

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Vol. 8, no. 2

229--236

EN

The paper evaluates effectiveness of fire drills for emergency and responding to PSC inspections on board. A brief background about the PSC inspection on fire drills on board is introduced in the beginning. Then the significance of effectiveness evaluation on fire drills is presented. Next, legal ground is discussed on International Conventions, including regulation of related regional group, national maritime laws and rules and Concentrated Inspection Campaign (CIC). Furthermore, PSC New Inspection Regime (NIR) for Paris MOU and Tokyo MOU are also discussed, and many deficiencies related to fire safety measures found in the PSC inspection are statistically analyzed. More importantly, the paper introduces System Engineering Theory, presents the principle and method of effectiveness evaluation, focuses on the preparation, performance and rehabilitation of fire drill and develops the Criterion of Effectiveness Evaluation. Finally, some suggestions are raised to carry out effectiveness evaluation for emergency and responding to the PSC inspection.

15

Investigation of the cook-off processes of HMX-based mixed explosives

Chen L., Ma X., Lu F., Wu J.

Central European Journal of Energetic Materials

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2014

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Vol. 11, no. 2

199--218

EN

In order to investigate the characteristics of the thermal reaction for two kinds of mixed explosives, PBXC-10 (HMX/TATB/Binder, 38/57/5) and JO-8 (HMX/Binder, 95/5), multi-point measured temperature cook-off tests were carried out at different heating rates. The thermal transfer and finite chemical reactions that include the β→δ transition of HMX, and the endothermic and exothermic cook-off processes were analyzed. A 3D model of the explosive cook-off test was developed to simulate the thermal and chemical behaviour in a thermal ignition. The decomposition mechanisms for HMX and TATB are described by the multistep, chemical kinetic model. The thermal properties, decomposition pathways, and chemical kinetic reaction rate constants for each component are used to develop the reaction courses at various weight percentages. The thermal decomposition reaction of a multi-component, mixed explosive can be predicted as long as the chemical kinetics model of each single-base explosive and binder are known. The phase transition of HMX has an influence on the temperature of the explosive, especially for an explosive with a high HMX content. For mixed explosives containing HMX and TATB, most of the heat release is produced by the decomposition of HMX before ignition, but TATB can delay the ignition time and decrease the reaction violence in the cook-off process.

16

Style Consistent Calligraphy Tablet Design

Yu K., Yuan Z., Wu J.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

138--139

EN

A style-consistent calligraphy tablet designing approach is proposed in this paper. The layout of the tablet is calculated firstly. The calligraphy characters are retrieved from the ones written by the specific calligrapher, while the style-consistency calligraphy character synthesis approach is applied to synthesize the non-existent ones. Finally, these characters are adjusted so that their styles are unified to be put on the calligraphy tablet according to the layout. The experiments show that the proposed approach can produce aesthetic calligraphy tablet.

PL

W artykule zaproponowano metodę projektowania tabliczek z kaligrafią, mający na celu ułatwienie i ujednolicenie produkcji. Zastosowany algorytm działania oparty został na bazie odniesienia znaków, przez co tworzone napisy mają jednorodny styl, co przekłada się na ich estetykę.

17

Design Optimization of QFP Structure for over 8Gbps Package Applications

Sun H., Cai Z., Wu J., Shi L., Sun L.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1b

284--289

EN

A 8Gbps packaging solution that uses low-cost quad flat pack (QFP) technology is presented. Since such a high speed is beyond the reach of traditional QFP package structure, a new design methodology with coplanar transmission line structure built into the lead frame has been developed. Due to the complexity level in QFP structure, each interconnect segment is accurately modelled in 3D model by utilizing the industry leading advance software tool, ANSYS HFSS. S-parameter, Time Domain Reflectometry (TDR) and Eye Diagram are used to help in understanding the contributing to the optimized QFP structure. The analysis results indicate that the optimized QFP structure can successfully achieve over 8Gbps single-end signal transmission.

PL

W artykule przedstawiono metodę zmiany struktury QFP na potrzeby przesyłu z prędkością 8Gbps. W celu analizy działania, stworzono model struktury o bardzo wysokiej precyzji, przy wykorzystaniu programów ANSYS HFSS. S-parameter, Time Domain Reflectometry (TDR) oraz Eye Diagram. Analiza wyników badań wykazuje, że wprowadzona optymalizacja pozwala na osiągnięcie założonej prędkości przesyłu danych.

18

An Online Monitoring System of Corona Loss of High Voltage Transmission Lines Based on Metalized Membrane Method

Luo Y., Liu H., Wang M., Xin X., Zhang Y., Li R., Wang G., Wu J., Bai X.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 10

217-220

EN

An online monitoring system of corona loss of high voltage transmission lines based on metalized membrane method is developed in this paper. The system includes 3 components: the upper computer, the conductor voltage acquisition module and the corona leakage current acquisition module. The corona leakage current acquisition module is set on the high voltage line. The transmission line is covered by a certain length of thin metalized membrane . The sampling resistance is put paralleling between metal layer and bundle conductor. The conductor voltage acquisition module is set in transformer substation. The two modules are synchronized by the rising edge of Pulse Per Second (PPS) emitted by Global Position System (GPS), and the data is sent to the public port of mobile telephone network by General Packet Radio Service (GPRS). The remote upper computer gets the data and calculates corona loss of each bundle conductor by visiting public port. The experiment results show that the system can monitor the corona loss accurately. The whole study is helpful in the further research of UHV transmission line’s corona in different environment and weather.

PL

Zaprezentowano metodę monitorowania strat powodowanych ulotem (wyładowaniem koronowym) w liniach transmisyjnych wysokiego napięcia. Do tego celu wykorzystano metalizowaną membranę. Układ składa się z trzech modułów: komputera, systemu akwizycji napia) ęcia i systemu akwizycji prądu ulotu. Linia transmisyjna jest pokryta na pewnej długości cienką metalizowaną membraną. Do lokalizacji ulotu zastosowano moduł GPS a do transmisji danych moduł GPRS.

19

Cooperative driving at isolated intersections based on the optimal minimization of the maximum exit time

Wu J., Abbas-Turki A., Perronnet F.

International Journal of Applied Mathematics and Computer Science

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2013

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Vol. 23, no. 4

773--785

EN

Traditional traffic control systems based on traffic light have achieved a great success in reducing the average delay of vehicles or in improving the traffic capacity. The main idea of these systems is based on the optimization of the cycle time, the phase sequence, and the phase duration. The right-of-ways are assigned to vehicles of one or several movements for a specific time. With the emergence of cooperative driving, an innovative traffic control concept, Autonomous Intersection Management (AIM), has emerged. In the framework of AIM, the right-of-way is customized on the measurement of the vehicle state and the traffic control turns to determine the passing sequence of vehicles. Since each vehicle is considered individually, AIM faces a combinatorial optimization problem. This paper proposes a dynamic programming algorithm to find its optimal solution in polynomial time. Experimental results obtained by simulation show that the proper arrangement of the vehicle passing sequence can greatly improve traffic efficiency at intersections.

20

Mathematic Simulating of Levofloxacin Release from Chitosan Nano/Microparticles

Guan J., Cheng P., Huang S., Li Z., Wu J., Gao P., Wang X., Zhang H.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 7b

345--349

EN

Chitosan based levofloxacin nano/microparticles were prepared by ionotropic gelatin and emulsion crosslinking technique. Their in vitro release profiles showed that microparticles had better sustaining delivery property than nanoparticles. The best fitting kinetics for nanoparticles and microparticles were First Order and Diffusion-Relaxation model respectively. The result suggests that levofloxacin delivery from nanoparticles was mainly controlled by diffusion process only, and that from microparticles was dominated by both diffusion and relaxation process.

PL

Mikro- i nanoelementy lekarstwa levofloaxin były wytwarzane techniką sieciowania emulsji. Dla lepszego dopasowania kinematyki opracowano model matematyczny. Stwierdzono że nanocząstki dostarczają materiał przez dyfuzję podczas gdy mikrocząstki wykorzystują też relaksację.