Advanced Materials Research Vols. 291-294

Abstract: Graft copolymerization of acrylic acid(AA) on starch to prepare super absorbent resin (SAR) under microwave irradiation were investigated using N,N-methylene bis-acrylamide as crosslinker and potassium persulfate as initiator. The influences of the amount of initiator and crosslinker, neutralization degree of acrylic acid(AA), ratio of starch to AA, microwave power level and irradiation time on the distilled water absorption amount of resin were investigated. The results indicated that it only needed 4min under the microwave level of 231W to obtain the resin with the maximum absorption amount of 1110g×g^-1, under the conditions that 0.3wt% initiator, 0.02wt% crosslinker, 60% neutralization degree of acrylic acid, the ratio of starch to acrylic acid of 0.25. Under microwave irradiation, the synthesis and drying of super absorbent resin could be completed at one step without nitrogen. Compared to conventional heating method, the methods had the striking advantages of short reaction time, simple process and low cost.

Abstract: The research in this paper optimized the extraction technique of lentinan with ultrasonic assistant method on the basis of hot water extraction technique, and investigated the promoting function of ultrasound to polysaccharides extraction. Extraction condition was selected by means of orthogonal experimental design, four factors and three levels L₉(3⁴), after key elements were respectively chosen through single factor experiments. Comparison between optimal extraction parameters of two method, hot water extraction technique and ultrasonic assistant extraction technique, showed decreased extraction temperature and significantly shortened extraction time, which existed in the second means, improved the extraction efficiency. Lentinus edodes polysaccharide extracted with ultrasonic assistant technique, the extraction rate and polysaccharide content percentage increased 6.22% and 8.66% respectively, comparative to which extracted with hot water extraction technique.

Abstract: Nature rubber (NR) is neither completely viscous nor elastic in nature, but viscoelastic in their properties. In the experiment, we used two types of equipments named rubber process analyzer (RPA) 2000 and mooney viscometer to characterize the viscoelastic properties of NR dried by microwave and hot-air, respectively. In present research, RPA tests on uncured NR dried by different methods were carried out using frequency and strain sweeps, and Mooney viscometer was detected using the big rotor at 100°C. The results showed that microwave drying has not influenced the viscoelastic properties of NR greatly, without changing the profiles of its rheological behavior. Compared with hot-air drying, the properties of NR dried by microwave improved significantly. As a new application, microwave drying technology offered an alternative way to the drying of NR.

Abstract: In this paper, a hybrid control system of the energy dissipation and isolation of flexible pile(EDIPF) is proposed, the dynamic analysis model of system is established, and its vibration and control equations are derived. Taking a typical flexible pile base-isolated structure for example, the isolation performance, control effect and main control parameters are studied. The results show that: the isolation and energy dissipation system of flexible pile can effectively reduce the seismic responses of structure, and to apply active control to this system can reduce the possibility of collision between pile and wall of pile hole. At the same time, the vertical loads and the stiffness of superstructure and piles have a significant influence on the control effect of structures.

Abstract: In the paper, the research on raising the grade of iron ore and dephosphorization for high-phosphorus oolitic hematite by coal-based carbothermal reduction in microwave field was carried out. The microwave action mechanism was analyzed by the aspects of ionic crystal lattice energy and thermodynamics and dynamics^[1]. The possibility of the application of microwave in raising the grade of iron ore and dephosphorization for high-phosphorus hematite was discussed. The research indicated that the primary structure of the high-phosphorus hematite was changed by the high-phosphorus hematite carbothermal reduction in microwave field, meantime the carbothermal reduction reaction activation energy was decreased and the reduction rate was speeded up^[2-4].

Abstract: The purpose of this research paper is focused on the high speed steel surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the high speed steel alloying with carbides using high power diode laser HPDL. Investigation indicate the influence of the alloying carbides on the structure and properties of the surface layer of investigated steel depending on the kind of alloying carbides and power implemented laser (HPDL). In the effect of laser alloying with powder of carbides occurs size reduction of microstructure as well as dispersion hardening through fused in but partially dissolved carbides and consolidation through enrichment of surface layer in alloying additions coming from dissolving carbides. Introduced particles of carbides and in part remain undissolved, creating conglomerates being a result of fusion of undissolved powder grains into molten metal base. The structural mechanism was determined of surface layers development, effect was studied of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer, and especially on its hardness, abrasive wear resistance, and roughness. It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.

Abstract: Using laser clads magnesium surface with Al-Si eutectic powder, analyzing the organization and composition of the cladding layer with scanning electron microscopy and EDS. The results show that the cladding layer mainly composed of β (Mg17Al12) phase, α (Mg) + β (Mg17Al12) eutectic, α(Mg) solid solution, Mg₂Si phase composition, and cladding layer and the substrate combined well, pores and cracks weren^,t found. Laser heat treatment of the cladding layer, then the bulky Mg₂Si phase was blown, small blocks were distributed in the grain boundary and improve the performance of the cladding layer.

Abstract: The PZT is used for piezoelectric actuators that have high area efficiency but no good machinability. A direct writing micro structures on PZT wafer by excimer laser micromaching method has been proposed and confirmed. PZT nano-needle structures have also been fabricated by the direct writing method only by changing the laser micromachiong process parameters. The fabricated nano-needle structures can be very useful because of the need for studies on ferroelectric size effects as well as for potential applications such as ultra-high density memory devices.The relationship of process depth with the excimer laser parameters has been tested.

Abstract: Two-photon three-dimensional optical data storage is an effective method for high capacity data storage. Based on DVD pick-up head and two-photon absorption, two-photon three-dimensional optical disk storage system is built, and operating principle of the overall system is in detail. In the servo module of three-dimensional optical disk storage system, DVD circuit control board (MT1389SE) is conducted on three-point improvement: extract focus servo error signal and servo error signal, increase four communications interfaces，increase photoelectric detectors; the extraction of focus and track servo signal on reading and writing module is analyzed in detailed. The measured principles and methods of the voice coil motor characteristic curve of Sanyo DVD pick-up head (SF-HD60S) are analyzed in detailed by using dual-frequency laser interferometer, which can be well meet the layer selection requirements of three-dimensional optical storage. DVD pick-up head applied in three-dimensional optical storage overcomes the limitations of three-dimensional scanning stage, integrates with existing DVD servo technology, and lays a solid foundation for practical use of two-photon three-dimensional optical storage.

Abstract: Laser transmission joining of dissimilar and biocompatible materials has potential applications in biomedical implants. In this work, a three-dimensional (3D) transient model for sequentially coupled thermal/mechanical analysis of laser transmission joining of 0.1mm thick PET film and 0.1mm stainless steel has been developed by using the ANSYS parametric design language APLD, along with a moving Gaussian laser heat source. It can be calculated how long it takes to reach the quasi-steady state through the stimulation of the temperature field. The calculated values of the joint width are in good agreement with the experimental results by comparison under conditions of different parameters, which indicates that the model is reliable and is helpful for optimizing process parameters. Then based on the temperature field, the residual stress field distribution on both PET and stainless steel surface is achieved by applying the indirect coupling methods to the analysis. this study also has laid a theoretical foundation for improving the stress distribution on the joint.