Reliability of Power Transmission and Transformation Facilities in 2010

Through the reliability analysis on transmission and transformation facilities with 220 kV or above voltage level in China in 2010, particularly by investigating the planned and unplanned outage of transformers, circuit breakers and overhead transmission lines with 220 kV, 330 kV and 500 kV level, the weak parts that may influence the operational reliabilities are figured out from technical and liability causes. Moreover, through the research on the device models and comparison of performance indices between domestic and imported devices, the trend of the reliability changes are identified so that the references can be provided for power enterprises to determine corresponding effective reliability measures during planning, design, implementation and production stages.

Simulation Analysis of Transmission-Line Impedance Transformers for Petawatt-Class Pulsed Power Accelerators

Based on the transmission line code TLCODE, a 1D circuit model for a transmission- line impedance transformer was developed and the simulation results were compared with those in the literature. The model was used to quantify the efficiencies of voltage-transport, energy- transport and power-transport for a transmission-line impedance transformer as functions of ψ （the ratio of the output impedance to the input impedance of the transformer） and Г （the ratio of the pulse width to the one-way transit time of the transformer） under a large scale of m （the coefficient of the generalized exponential impedance profile）. Simulation results suggest that with the increase in Г, from 0 to ∞, the power transport efficiency first increases and then decreases. The maximum power transport efficiency can reach 90% or even higher for an exponential impedance profile （m = 1）. With a consideration of dissipative loss in the dielectric and electrodes of the transformer, two representative designs of the water-insulated transformer are investigated for the next generation of petawatt-class z-pinch drivers. It is found that the dissipative losses in the electrodes are negligibly small, below 0.1%, but the dissipative loss in the water dielectric is about 1% to 4%.

Research on the risk-evaluation model of power transmission and transformation projects based on multilevel fuzzy-thought weighting for cloud-model improvement

The risk evaluation of power transmission and transformation projects is a complex and comprehensive evaluation process influenced by many factors and involves many indicators.In order to solve the uncertainty and fuzziness problems in the process of the multilevel fuzzy risk evaluation of power transmission and transformation projects,this paper introduces the cloud theory,which is specialized in the study of uncertainty problems and constructs the multilevel fuzzy comprehensive risk-evaluation model of power transmission and transformation projects based on the improved multilevel fuzzy-thought weighting based on the cloud model.Finally,the risk of the Beijing 220-kV Tangyu power transmission and transformation project is evaluated and the feasibility of the evaluation model is verified.The results of the evaluation and the evaluation layer cloud model are combined with MATLAB simulation to show that the risk level of the project is between large risk and general risk.

Underdetermined Blind Source Separation of Adjacent Satellite Interference Based on Sparseness

The problem of underdetermined blind source separation of adjacent satellite interference is proposed in this paper. Density Clustering algorithm(DC-algorithm) presented in this article is different from traditional methods. Sparseness representation has been applied in underdetermined blind signal source separation. However, some difficulties have not been considered, such as the number of sources is unknown or the mixed matrix is ill-conditioned. In order to find out the number of the mixed signals, Short Time Fourier Transform(STFT) is employed to segment received mixtures. Then, we formulate the blind source signal as cluster problem. Furthermore, we construct Cost Function Pair and Decision Coordinate System by using density clustering. At the end of this paper, we discuss the performance of the proposed method and verify the novel method based on several simulations. We verify the proposed method on numerical experiments with real signal transmission, which demonstrates the validity of the proposed method.

Prediction model for cost data of a power transmission and transformation project based on Pearson correlation coefficient-IPSO-ELM

In view of the difficulty in predicting the cost data of power transmission and transformation projects at present,a method based on Pearson correlation coefficient-improved particle swarm optimization(IPSO)-extreme learning machine(ELM)is proposed.In this paper,the Pearson correlation coefficient is used to screen out the main influencing factors as the input-independent variables of the ELM algorithm and IPSO based on a ladder-structure coding method is used to optimize the number of hidden-layer nodes,input weights and bias values of the ELM.Therefore,the prediction model for the cost data of power transmission and transformation projects based on the Pearson correlation coefficient-IPSO-ELM algorithm is constructed.Through the analysis of calculation examples,it is proved that the prediction accuracy of the proposed method is higher than that of other algorithms,which verifies the effectiveness of the model.

Fibrinogen Adsorption on Biomaterials as Characterized by Transmission FTIR Spectroscopy

The adsorption of plasma proteins onto biomaterials can be characterized by either the amount of adsorbed protein or the conformation of the adsorbed proteins. The adsorption characteristics of biomaterials are important for hemocompatibility evaluation. In this investigation, the amount of adsorbed human fibrinogen (HFG) and the conformation of the adsorbed HFG on different surfaces were measured simultaneously using transmission FTIR. The surface materials included CaF 2, polymethyl methacrylate (PMMA), type II polyurethane made by Chengdu University of Science & Technology, pellethane 2363 55D and pellethane 2363 80A. The results indicate that both the amount of adsorbed protein and the conformation of the adsorbed protein can be measured simultaneously using a single transmission FTIR technique. The result also suggests that a single parameter, either the adsorbed amount or the conformation of the adsorbed HFG, can not provide complete information about the hemocompatibility of the biomaterials.

Stress-Induced Martensitic Transformation of Zr_(50)Cu_(25)Ni_(10)Co_(15) Nanocrystals Embedded in an Amorphous Matrix

The stress induced martensitic phase transformation of spherical ZrCu nanocrystals embedded in an amorphous matrix was studied in this paper. Microstructural observations revealed that the martensitic transformation of the nanocrystal was hindered by the surrounding amorphous coating. The existence of two-step transformation from the austenite phase（B2） to the base structure martensite（B19＇） and finally to the most stable superstructure martensite（Cm） was also demonstrated. The Cm martensite with（021） type I twinning symmetrically accommodation was surrounded by the B19＇ martensite with dislocation morphologies.

Capuli cherry-mediated green synthesis of silver nanoparticles under white solar and blue LED light

In this article, the Capuli （Prunus serotina Ehrh. var. Capuli） cherry extract was used for the synthesis of silver nanoparticles （AgNPs） in the presence of white/visible solar and blue light-emitting diode （LED） light. For the characterization of the extract and the AgNPs, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy were employed, along with hydrodynamic particle size analysis, trans- mission electron microscopy and X-ray diffraction. The Ag nanospheres obtained using white light were 40-100 nm in diameter and exhibited an absorption peak at λmax= 445 nm, whereas those obtained using blue LED light were 20-80 nm in diameter with an absorption peak at λmax= 425 nm. Thermal analysis revealed that the content of biomolecules surrounding the AgNPs was about 55-65%, and it was also found that blue LED light AgNPs （56.28%, 0.05 mM） had a higher antioxidant efficacy than the white solar light AgNPs （33.42%, 0.05 mM） against l,l-diphenyl-2-picrylhydrazyl. The results indicate that obtaining AgNPs using a blue LED light may prove to be a simple, cost-effective and easily reproducible method for creating future nanopharmaceuticals.

Influence of tribofilm on superlubricity of highly-hydrogenated amorphous carbon films in inert gaseous environments

In this study,we mainly focus on the structural morphology and inter-atomic bonding state of tribofilms resulting from a highly-hydrogenated amorphous carbon(a-C:H) film in order to ascertain the underlying mechanisms for its superlubric behavior(i.e.,less than 0.01 friction coefficient).Specifically,we achieved superlubricity(i.e.,friction coefficients of down to 0.003) with this film in dry nitrogen and argon atmospheres especially when the tribo-pair is made of an a-C:H coated Si disk sliding against an a-C:H coated steel ball,while the a-C:H coated disk against uncoated ball does not provide superlubricity.We also found that the state of superlubricity is more stable in argon than in nitrogen and the formation of a smooth and uniformly-thick carbonaceous tribofilm appears to be one of the key factors for the realization of such superlubricity.Besides,the interfacial morphology of sliding test pairs and the atomic-scale bond structure of the carbon-based tribofilms also play an important role in the observed superlubric behavior of a-C:H films.Using Raman spectroscopy and high resolution transmission electron microscopy,we have compared the structural differences of the tribofilms produced on bare and a-C:H coated steel balls.For the a-C:H coated ball as mating material which provided superlow friction in argon,structural morphology of the tribofilm was similar or comparable to that of the original a-C:H coating;while for the bare steel ball,the sp^2-bonded C fraction in the tribofilm increased and a fingerprint-like nanocrystalline structure was detected by high resolution transmission electron microscopy(HRTEM).We also calculated the shear stresses for different tribofilms,and established a relationship between the magnitude of the shear stresses and the extent of sp^3-sp^2 phase transformation.

Systematic study of Ce^(3+) on the structural and magnetic properties of Cu nanosized ferrites for potential applications

Ce^（3＋） substituted Cu-spinel nanoferrites CuCe_xFe_（2-x）O_4（x=0.00, 0.02, 0.04, 0.06, 0.08 and 0.10） were synthesized via sol-gel self-combustion hybrid route. Single phase spinel ferrite of Cu nanoferrites were examined using X-ray diffraction（XRD） analysis whereas the multiphase structure was observed as Ce contents increased from x=0.06. Field emission scanning electron microscopy（FESEM）, Thermogravimetric and differential thermal analysis（TGA and DTA） and Fourier transform infrared spectroscopy（FTIR） were used to find out the morphology phase and metal stretching vibrations of Ce^（3＋） substituted nanocrystalline ferrites. The crystallite size was increased and found in the range of 25-91 nm. The agglomerations in Cu ferrite samples increase as the Ce^（3＋） concentration increases. The magnetic properties such as remanence, saturation magnetization, coercivity, Bohr magneton and magnetocrystalline anisotropy constant（K） were determined using M-H loops recorded from a vibrating sample magnetometer（VSM）. Saturation magnetization, remanence and coercivity are increased as the Ce^（3＋）contents increase in Cu nanocrystalline samples. Moreover, law of approach to saturation（LoA） was used to calculate the maximum value of saturation for Ce-doped Cu nanoferrites. The soft magnetic behaviour of the Cu nanoferrite is observed as compared to the samples substituted with the increased Ce contents in Cu nanocrystalline ferrite. Bohr magneton and magnetocrystalline anisotropy are found to increase with the substitution of rare earth Ce^（3＋） contents in Cu spinel nanocrystalline ferrite. Cedoped Cu nanocrystalline ferrites with excellent properties may be suitable for potential applications in sensing, security, switching, core, multilayer chip inductor, biomedical and microwave absorption applications.