Advanced Materials Research Vols. 152-153

Abstract: A novel CdTe/Ni QDs which combined both magnetism and fluorescence was successfully synthesized and its optical properties were investigated. Ni magnetic nanoparticles (MNPs) were synthesized and used as magnetic core, CdTe quantum dots (QDs) were applied as fluorescent shell material, the qualified magnetic CdTe/Ni quantum dots (mQDs) were achieved via layer-by-layer process using 1,6-hexylenediamime as linker, surface charge types of MNPs and mQDs were confirmed with a delsa nano beckman coulter. Morphology of the prepared Ni MNPs and CdTe/Ni mQDs was characterized by transmission electron microscopy (TEM), and optical properties were investigated with fluorescence spectrum (FS). Qualified CdTe/Ni mQDs with high fluorescence and narrow maximum emission peak width were obtained under the optimum conditions. Surface zeta-potential of CdTe QDs and Ni MNPs were estimated to be -36.2 and 27.97mV, respectively. TEM data indicated that ca 20nm of Ni MNPs and ca 25nm of CdTe/Ni mQDs were prepared, respectively; the size-increasing indicated the formation of CdTe shell on the Ni MNPs core. Narrow half peak width of emission peak was detected and calculated to be about 50nm via FS. High fluorescence intensity of CdTe/Ni mQDs was determined and brilliant yellow solution was observed when excited under UV360nm. The synthesized CdTe/Ni mQDs showed excellent magnetic property, and can be magnetically concentrated with a common magnet. The obtained data indicated that the prepared bi-functional CdTe/Ni mQDs possess excellent magnetic and fluorescent properties, and it can be used as a energy donor in DNA sensing based on fluorescence resonance energy transfer (FRET).

Abstract: We performed first-principles calculations to the electronic structure and bonding characteristic of NdMgNi4H4. The calculation results show that the H—Ni units are formed by the covalent H—Ni bonds, the surrounding Mg and Nd atoms provide electrons to the H—Ni units, and the Ni-Ni bonds between the different H—Ni units are covalent, making the H—Ni units not isolated. These bonding characteristics show that NdMgNi4H4 is similar with interstitial metal hydride in some aspects, and similar with complex metal hydrides in other aspects, indicating NdMgNi4H4 is the intermediate between interstitial metal hydrides and complex metal hydrides.

Abstract: The thermal stability of Al-Cu-Mg-Ag alloys under-aged and peak-aged was analyzed by tensile testing and transmission electron microscopy (TEM). And the microstructural evolution and mechanical properties of Al-Cu-Mg-Ag alloy during thermal exposed at elevated temperature were also studied. The results show that the under-aged Al-Cu-Mg-Ag alloy possessed better thermal stability compared with the peak-aged alloy when exposed at 150 . The tensile strength of the peak-aged alloy decreased with prolonging the holding time. While that of the under-aged alloy increased and then decreased with a peak of 524 MPa after exposed for 20 h, which was 19 MPa higher than that of the peak-aged alloy. Meanwhile the precipitations were distributed dispersively and amount of fine phases were observed. The tensile strength of the under-aged alloy was 434 MPa after exposed for 1000 h at 150 . When exposed at 200 , the tensile strength of the under-aged sample decreased and the prolongation increased with prolonging the thermal exposure time. The tensile strength of the sample decreased dramatically when exposed at 250 and 300 and the strengthening phases coarsened dramatically and evolved to the equilibrium phases . The width of the precipitation free zone (PFZ) increased with increasing the thermal exposure temperature and the distribution of the precipitations on the boundaries became discontinuous.

Abstract: (Al3Ti)p/6351 composites were in situ synthesized via direct melt reaction between 6351 wrought aluminum alloy and K2TiF6 at 720°C. OM, SEM and EDS are utilized to analyze the microstructure and components of composites. The fusing agents of CaF2 and LiCl are mixed with K2TiF6 to lower the temperature of initial in situ reaction. The volume fraction of Al3Ti is 3%.The size of Al3Ti is in the range of 2~4μm, which is much lowered than that fabricated by conventional process. Due to the calcium element from CaF2 the size of Mg2Si phases are decreased to 1~2μm.The microns of independent silicon phases are also observed in the squeezed section. The grain size of α-Al is fined to 30~40μm, which is due to the disperse effect of Al3Ti. The tensile, yield properties and elongation are at room temperature are 365MPa, 320MPa and 10.2%.

Abstract: TiO2 thin film containing SrFe12O19 powders on the surface of 316L stainless steel and NiTi alloy was prepared through sol-gel method and micro-magnetic field was established by the magnetization process applied on the coating. The coating film was characterized by x-ray diffraction (XRD) and the surface morphology of the coating was observed by scanning electron microscope (SEM). This blood compatibility thin film was evaluated by dynamic cruor time of blood test.The results show that dynamic cruor time of blood is prolonged by the micro-magnetic field of the thin film, indicating improved blood compatibility.

Abstract: There is a great potential market for biodegradable materials products and process equipment, long time molding, lower heat transfer efficiency, uniform temperature distribution and other issues have been studied focused, combined with biomass biodegradable food boxes forming technology research. The die temperature distribution and the temperature difference between upper and lower template have been analyzed by simulation model in this paper. According to analyzing, the die structure has been changed, so as to meet the requirements of the upper and lower temperature.

Abstract: MgAl-hydrotalcite compounds (MgAl-HT) with different n(Mg)/n(Al) ratios were synthesized by coprecipitation method. XRD and FT-IR were performed to characterize the structure of MgAl-HT. TG-DTG technology was adopted to study the thermal decomposition behavior. It was discovered that the thermal decomposition proceeded in two stages when the ratios of n(Mg) toward n(Al) being to 2~4. The kinetic parameters of the thermal decomposition procedure were also calculated by Ozawa method, which demonstrated that the value of active energy showed dynamic distribution. At each step of the decomposition behavior, the value of active energy decreased at first and then rose. The value of active energy for the deformation of the water in the interlayer was located within 45~90 kJ•mol-1 and within 150~230 kJ•mol-1 for the deformation of structure hydroxyl. Those characteristics were discussed and explained according to relative theory.

Abstract: Biodegradable material is a kind of green material, which is easily reclaimed and reused, and does not pollute the environment and can decompose quickly, there is not insurant produce after trash. This study aims to looking for new material and low price to produce dishware. Food dishware we produced using different biodegradable material cooperating with Jiufa Group Company, the main material is pure plant fiber and starch, additive edible material, and degradable material. (1) The mix of the dishware material technology and the spark technology has been studied. (2) The test of biodegradable of the dishware has been studied, and the result shows this packaging material can be separated to carbon and water finally after disused by the action of animalcule, in the water and air. The energy sources and resource can more reduce for this degradable material to produce dishware, so as to green and keep environment friendly, safe to use.

Abstract: In the field of pharmaceutical industry, the controlled-release drugs have received considerable attention in the last years. Impregnation using supercritical fluid technology has already proven its feasibility in the preparation of controlled release systems. The use of supercritical fluids such as supercritical CO2 has provided a ‘clean’ and effective alternative to traditional methods of drug releasing and polymer processes. In particular, scCO2 has a number of unique properties that make it possible to process both bioactive molecules and amorphous polymers without using toxic organic solvents or elevated temperatures. A high purity product, free of residual solvents is obtained, since no organic solvents are involved in the impregnation process. Here, we review the advantages of supercritical fluid and the preparation of controlled-release drugs by supercritical solvent impregnation.

Abstract: It’s important to prevent the happening of biological fouling because it can increase friction and accelerate corrosion to the marine ships. In this paper, PDMS elastomers with different modulus between 0.43 and 2.35MPa were prepared by hydrosilylation reactions, and the effect of modulus on the adhesion of diatom (Navicula sp) and ulva spore (Pertusa) were investigated. Results reveal that the density of adhered diatoms and ulva spores have no relation with elastic modulus(E), but the removal ratio of adhered diatoms and ulva spores increase significantly with the decrease of elastic modulus, and the deep study find it decrease in proportion to E1/2.