Advanced Materials Research Vols. 129-131

Abstract: With the rapid growth of information resources and increasing individual demands of farmers, the problem of how to organize complicated information effectively in agricultural risk management and provide efficient information services has become more and more important. Research on architecture of agricultural risk-oriented domain ontology-based information integrated service is studied. The ontology molecule theory, which is a new theory in ontology field, is introduced and utilized in this paper. Based on the ontology molecule theory, the paper builds a frame of the agricultural risk ontology and proposes the architecture and implementation of the agricultural risk-oriented information integrated service. At the end, this article points out that the future research is to establish an ontology-based information service system for the agricultural risk management, in order to better predict the agricultural risk and reduce its effect to farmers.

Abstract: with economic globalization and market-oriented agricultural economy, the impact factors of agricultural risks become more complicated. As a variety of factors intertwine together, the traditional Expert System is difficult to identify and manage agricultural risks, which greatly hampers the process of agricultural risk management. To overcome this problem, we introduce the ontology theory. By constructing agricultural risk ontology and agricultural risk strategy ontology, we can resolve the problem of agricultural risk's description and identification, and improve the efficiency and reliability of agricultural risk management. In this paper, we introduce the domain ontology theory to the field of agricultural risk management, and describe the basic process of the domain ontology-based agricultural risk management. And then, we propose a framework of ontology-based agricultural risk management and specifically introduce each module in the framework. Meanwhile, based on the method of building ontology, this article constructs the basic frame of the agricultural risk ontology. Finally, to take the drought risk for example, the paper analyses the implementation process and technologies of the domain ontology-based agricultural risk management.

Abstract: This paper presents a simulation system based on STEP-NC that can verify STEP-NC program and demonstrate the running of STEP-NC system (CNC system based on STEP-NC). NC Programs used in the STEP-NC system are in XML format. The overall architecture of the system which consists of feature extraction module, graphical modeling module, movement modeling module, feature library, simulation drive module and user interface is established. Some key technologies to implement simulation system are discussed in details. The simulation system shows great potential to the development and popularization of STEP-NC system.

Abstract: The study investigated the crystallization and sintering behavior in Li2O-Al2O3-SiO2 (LAS) glass powder. The sintered sample was produced with a glass particle (Φ=44㎛). The relative density and transmittance of the sintered samples showed the highest value at the temperature of 650°C. In the higher temperature than 650°C, the crystal growth occurred to decrease the densification of Li2O-Al2O3-SiO2 (LAS) glass powder. Main crystalline phase was β-spodumene in the glass powder. From the non-isothermal differential thermal analysis, the crystallization of the particles (Φ=44㎛) was observed at 640~684°C with respect to the heating rate. The activation energy of crystallization (EC) and Avrami constant (n) calculated by Kissinger and Ozawa equations indicated that the surface and the bulk crystallization occurred simultaneously in the glass. The optimum sintering condition of this glass powder was 650°C without crystal growth of β-spodumene, although a nucleation or nano-crystal growth occurred.

Abstract: Studies on digital library information service and the key technologies have both recently witnessed significant progress while still remains some open problems on how to apply the key technology in the digital library. Therefore there is an indisputable value in analyzing the superior and difference of key technologies used in the digital library information service. This paper introduces the main organizations and business contents of the digital library, the key technology of digital library information service, the analysis on key technologies and efficiency of digital library information service, and analyzes the application prospects on key technologies of digital library information service in china. The application of technologies will make the digital library information service more productive and effective to the public and can effectively solve various problems. The emergence of information technology provides good prospects of application for the digital library information service.

Abstract: Magnesium powders were sintered by using spark plasma sintering (SPS) and conventional pressureless sintering (PLS) techniques at sintering temperatures ranged from 552°C to 605°C to investigate effect of sintering method on microstructure and mechanical properties of sintered magnesium. High densed magnesium could be obtained by using spark plasma sintering technique compared to conventional presureless sintering at the same sintering temperature. It was found that the ultimate tensile strength increased with increasing sintering temperature for both the materials sintered by PLS and SPS. The magnesium samples prepared by SPS showed better mechanical properties than those prepared by PLS. The microstructural observations revealed that the grain growth was not significant in SPS process compared to PLS, which would enhance the mechanical properties of the SPS sintered magnesium.

Abstract: In this paper the measurement concept of QoE related to mobile video streaming in 3G network environment is introduced. The state-of-the-art tools created for automatic data capturing in field experiments are compared. Results of a semi-Living Lab experiment using the MyExperience in-situ measurement tool are presented and analyzed. Five orthogonal QoE aspects are proposed by performing Principal Component Analysis on 17 question items from the questionnaires. Technical-quality related QoE aspects are modeled by the technical QoS parameters (at wireless infrastructure and network level) measured during the experiment. It is shown that QoE of mobile video streaming is influenced by the QoS and by the context also.

Abstract: K-constant fatigue crack growth (FCG) tests were conducted on low carbon steels with uniformly distributed hard particle with different of pearlite, bainite and martensite in a soft ferrite matrix. The FCG tests by using a single edge cracked tension (SECT) type was performed inside a scanning electron microscope chamber equipped with a servo-hydraulic fatigue machine. During the test, in-situ crack path observation was carried out to identify the crack tip stress shielding phenomena. From the results, influence of hardness of second phase particle on the FCG behavior in Paris regime was systematically investigated. The results revealed that the ferrite-martensite (FM) steel showed significantly higher FCG resistance compared to that of ferrite-pearlite (FP) and ferrite-bainite (FB) steels. The harder second phase particle would be more difficult to be plastically deformed, which would induce higher plastic constrain. This higher plastic constrain may result in significant crack closure effect and stress shielding effect, thereby increasing higher FCG resistance.

Abstract: Poplar engineering biocomposites is a new engineering materials. In order to evaluate its potential environmental risk to human, the volatile organic compounds of poplar engineering biocomposites were adsorbed and determined by TD-GC-MS. The result were: (1) The main constituents of volatiles at 40°С were bicyclo[2.2.1]heptan-2-one, 1,7,7- trimethyl-, (1r)-(31.55%), 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester(14.94%), 2,6,10,14,18,22- tetracosahexaene, 2,6,10,15,19,23-hexamethyl-(7.34%), [1,1':3',1''-terphenyl]-2'-ol(5.97%), cedrol (5.29%), caryophyllene(5.26%), 3-[(1z)-1,3-butadienyl]-4-vinylcyc lopentene(3.92%), etc. (2) The main constituents of volatiles at 60°С were 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester(17.13%), [1,1':3',1''-terphenyl]-2'-ol(9.11%), camphor(8.6%), 4-imidazolidinone, 5-(phenylmethyl)-2-thioxo- (7.6%), cedrol(7.26%), 2,5-cyclohexadiene-1,4-dione, 2,5- diphenyl-(4.58%), 1h-indole, 5-methyl- 2-phenyl-(3.94%), 2,6,10,14,18,22-tetracosahexaene, 2,6,10,15,19,23-hexamethyl- (3.63%), phenol,2,4-bis(1,1-dimethylethyl) (3.56%), etc. So the poplar engineering biocomposites was safe under 40-60°С.

Abstract: BiVO4/FeVO4 composite photocatalyst samples were prepared by calcining the mixture of FeVO4 and BiVO4 precusor which were prepared through liquid phase precipitation method for further increasing the photocatalytic efficiency of FeVO4. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microsoope（SEM）and specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. The XRD patterns indicate that BiVO4/FeVO4 composite photocatalysts consist of triclinic phase and the lattice was not distorted beacause of doping Bi. But the morphology change greatly and the specific surface area has little change. In the experimental conditions used, the optimal photocatalytic activity for all the prepared samples was reached when BiVO4 doping was 22 at%. The degradation rate of MO was increased by 20％ or so than that of pure FeVO4.