Advanced Materials Research Vols. 197-198

Abstract: The calcium carbonate crystallization were controlled by Ca²⁺ concentration in the 10% (V/V) egg white protein solution and the morphology, structure and thermal decomposition of which were characterized by FT-IR, SEM, XRD and TG. The results showed in egg white protein solution system, concentration of Ca²⁺ had significant effects on the crystallized morphology, orientation and crystallinity of calcium carbonate. Calcium carbonate particles have more uniformed calcite and vaterite mixed crystallization in low Ca²⁺ concentration while calcium carbonate tends to form mixed particle sizes and more complete calcite crystallization in high Ca²⁺ concentration.

Abstract: In recent years, the research on the medical robot's already became a new domain about the robot application, particularly the special medical robot already became a direction of the medical robot develops. This article started with the medical robot organization design, construct the three-dimensionalmodel,designed master-Slave Medical robot control system overall project, determined a new two-way control method of force telepresence, developed Master-Slave medical robot control system's simulation software, and conducted the experimental study, the experimental result showed that this simulation system had the very good timeliness and the accuracy.

Abstract: Nitrogen-doped titanium oxide (TiO_2-xN_x) films were prepared by an improved ultrasonic spray pyrolysis device with buty1 titanate as the titanium source and ammonia as the nitrogen source. X-ray diffraction technique, scanning electronic microscope and UV-VIS spectroscopy were applied to study the microstructure, surface morphology and optical properties of the resulting films. The XRD peak intensity of the as-prepared films decreased with the increasing of nitrogen content and increased with the increasing of temperature, which indicates that the N doping introduced defects or strain in the TiO₂ film. The SEM results indicate that all the samples have a nano-sized uniform surface. The smallest band gap and best hydrophobicity are obtained at the nitrogen concentration of 4 at. % and deposited at 400°C. The blood compatibility of TiO_2-xN_x thin films was observed through platelet adhesion. The experiments results show that the amount of thrombus on the TiO_2-xN_x thin films is much less than that of pyrolytic carbon. The experimental results show that the nano-sized TiO_2-xN_x thin films will be a new kind of promising materials applied to artificial heart valve and endovascula stent.

Abstract: Experimental study of radial ultrasonic vibration aided grinding of sintered Nd-Fe-B permanent magnetic material was conducted contrasted with traditional grinding. The effect on normal grinding force of grinding parameters was analyzed respectively in the two grinding processes. Experimental results indicate that the discontinuous grinding mechanism caused by ultrasonic vibration is the main factor that reducing the normal grinding force. The process of radial ultrasonic vibration aided grinding is especially suitable for shape machining of sintered Nd-Fe-B permanent magnet.

Abstract: Titanium alloys are commonly used in biomedical application in hard tissues replacement especially for knee and hip implants. Surface modifications are required prior to diamond coating process for improving tribological and wear properties of the titanium alloy. In this study, experiments were carried out to investigate the effects of different carburizing times on the adhesion strength of carbide layer formed on the Ti-6Al-7Nb. Prior to carburization process, all samples were treated to remove residual stress and oxide scales by annealing and pickling processes respectively. Hard wood charcoal powder was used as a medium. The carburizing process was carried out for 6, 12 and 24 hours at 950 °C under normal atmospheric condition. Surface morphology, carbide layer thickness and adhesion strength were evaluated using SEM, XRD, 3D Surface Profilometer and Blast Wear Tester (BWT). It is found that a mixture of oxide and carbide layers formed on the substrate and the thickness of these layers increases with carburizing time. It is also revealed that the 24 hr carburizing time provides the strongest adhesion strength among the three and TiC as the dominant layer.

Abstract: Encapsulation glycoprotein extracted from kiwifruit in chitosan-alginate microspheres was prepared by ionic gelation method for controlling release by using various combinations of chitosn and Ca²⁺ as cation and alginate as anion. The concentration of chitosan, sodium alginate and calcium chloride could affect glycoprotein loading efficiency and the total release capacity of glycoprotein from chitosan-alginate microspheres. The maxmum amount of glycoprotein loaded and the minimum total release capacity were attained when 2% alginate, 0.7% chitosan, and 0.2M Ca²⁺ were crosslinked at pH 5.5, 37°C.

Abstract: The extraction technique of flavonoids from the tender leaves and fruits of medlar (Lycium chinense Miller) were investigated, and the flavonoids content from both was compared. Through single-factor and the L9 (3⁴) orthogonal design, the optimal extraction parameters were determined. The results showed that the content of flavonoids in the tender leaves was significantly higher than in the fruits. There were four important factors influencing the yield of flavonoids, including ethanol concentration, extraction time, solid-liquid ratio and extraction temperature. As for leaves, the optimum extraction parameters were 80% ethanol concent, solid-liquid ratio 1:50, two times per 40min, and 60°С . In order to extract flavonoids from fruits, the optimum parameters of ethanol content, solid-liquid ratio, extract times, and temperature were 80%, 1:50, 2 per 30min and 60С respectively. Under the optimum condition, the yield of flavonoids from leaves and fruits were 47.371 and 9.593 mg.g^-1 respectively.

Abstract: A fixed bed of raw rice husk was used for the removal of Zn (II) from aqueous solution. The material as adopted was found to be an efficient media for the removal of Zn (II) in continuous mode using fixed bed column. Different column design parameters like depth of exchange zone, flow rate and initial concentration were calculated. When conducted with Zn (II) concentration 10 mg.L^-1 and flow rate 10 ml.min^-1 with different bed depths such as 3, 6 and 9 cm, the equilibrium uptake was 3.366, 2.847 and 2.764 mg.g^-1, respectively. The equilibrium uptake decreased from 2.802 to 1.975 mg.g^-1 with increasing of flow rate from 5 to 15 mL.min^-1 and increased from 2.764 to 3.798 mg.g^-1 when initial concentration increased from 10 to 30 mg.L^-1. The dynamics of adsorption process was modeled by bed depth service time (BDST), and indicating the validity of BDST model when applied to the continuous column studies.

Abstract: Drug delivery systems with active targeting ligand provide improved therapeutic efficiency due to the selectivity towards tumor cells. In this paper we prepared drug loaded nanoparticles (NPs) using folate (FA) incorporated chitosan (FA-CS) based on ionic gelation technology. FA-CS NPs were spherical in shape with an average particle size of 100 nm, while 5-fluorouracil (5-FU) loaded NPs became less circular with average particle size of 100-500 nm. NPs made from FA-CS conjugates exhibited improved capability to encapsulate hydrophilic 5-FU. It was found 5-FU distributed in FA-CS NPs in solid solution state. In vitro release results demonstrated the release of 5-FU from FA-CS NPs was more controllable as compared to that of CS NPs.

Abstract: In this Study, the Tripolyphosphate-Chitosan (TPP-CS) Nano-Carrier was Prepared by Polyelectrolyte Complexation. TPP and CKGM are Polyanion, and can Interact with Cationic Chitosan by Electrostatic Forces. the Nanoparticles Size was Analyzed by the Transmission Electron Micrographs (TEM) and Scattering Electron Micrographs (SEM). FTIR Confirmed Tripolyphosphoric Groups of TPP and CKGM Linked with Ammonium Groups of Chitosan in the Nanoparticles. the CS Nps were Loaded with the Anticancer Drug, Berberine, by Different Concentration of Cross-Linking Agent. the Zeta Potentials of CKGM and CS were Shown as a Function of Ph. it was Observed that CS has Strong Interaction with CKGM about Ph 5.5. the CKGM-CS Nanoparticles were Formed by Mixed Different Weight Ratio of CS and CKGM. the Morphology of CKGM-CS was Characterized by FESEM. the Size of CKGM-CS Particles was Smaller than 150 Nm. the Zeta Potential of CKGM-CS Particles was Proved that the Polymer Ratio can Control the Charge Density.