Effect of Structural Parameters on the Thermal Stress of a NiFe2O4-Based Cermet Inert Anode in Aluminum Electrolysis

Inert anode has been a hot issue in the aluminum industry for many decades. With the help of FEA(finite element analysis) software ANSYS,a model was developed to simulate the thermal stress distribution working condition of an inert anode. To reduce its thermal stress,the effect of some parameters on the thermal stress distribution was investigated,including the anode height,the anode radius,the hole depth,the hole radius,and the radius of inner chamfer and outer chamfer. The results showed that in the actual working condition of an inert anode,there existed a large axial tensile stress near the tangent interface between the anode and bath,which was the major cause of anode breaking. Increasing the anode height and reducing the hole depth properly seemed to be beneficial for the stress distribution. With the increase of anode radius,the stress distribution became better first and then deteriorated,the reasonable value was between 0.045 to 0.06m. The hole radius had a significant effect on the stress and a smaller radius would reduce the thermal stress. The effect of the radius of the inner chamfer and the outer chamfer was less than other parameters.     

3-D Finite Element Analysis of the Effect of Welding Residual Stress on Hydrogen Diffusion in Hydrogen Contained Environment

The hydrogen distribution of 16MnR steel weldment in hydrogen contained environment was calculated using the finite element method (FEM). The effect of welding residual stress on hydrogen diffusion has been discussed using a 3-D sequential coupling finite element analysis procedure complied by Abaqus code. The hydrogen diffusion coefficient in weld metal, the heat affected zone (HAZ), and the base metal of the 16MnR steel weldment were measured using the electrochemical permeation technique. The hydrogen diffusion without the effect of stress was also calculated and compared. Owing to the existence of welding residual stress, the hydrogen concentration was obviously increased and the hydrogen would diffuse and accumulate in the higher stress region.     

Multifunctional Modification of SIS Membrane with Chimeric Peptides to Promote Its Antibacterial,Osteogenic, and Healing-Promoting Abilities for Applying to GBR

Guided bone regeneration (GBR) technology is the most widely used and stable method for bone defect repair. However, infectious bone defect limits the application of this technique. Herein, a small intestinal submucosa (SIS) membrane modified by chimeric peptides as a new type of GBR membrane is developed for efficacious tissue regeneration. Based on the main components of SIS membrane are I and III collagen, collagen binding peptides TKKTLRT and KELNLVY sequences are used to construct chimeric peptides with healing-promoting peptide Hst1 or antibacterial osteogenic peptide JH8194, so as to realize the specifically target of SIS. This method achieves the fast and efficient multifunctional modification of SIS membrane. The chimeric peptides modified SIS (pSIS) membrane has satisfactory biocompatibility and a certain degree of antibacterial activity. Moreover, pSIS promotes the osteogenic related factors expression of rat bone mesenchymal stem cells and demonstrates great bone regeneration in rat skull defect model. Furthermore, pSIS accelerates the migration of oral epithelial cells in vitro and activate integrin α3β1 signal pathway contribute to wound healing. This study presents a novel biomaterial design of GBR membrane, specifically for the treatment of infectious bone defects.     

CNOOC to Boost Its Output Significantly in 2008

CNOOC Ltd., which is the listing arm of China National Offshore Oil Corporation, the country＇s No. 3 oil producer, said in late January that its crude oil and natural gas output would grow up to 17.8 percent this year as 10 new projects started operations. It expected net production to hit 195-199 million barrels of oil equivalent （BOE） in 2008, compared with the estimated output of 169-171 million BOE in 2007.     

Growth Morphologies of a Binary Alloy with Low Anisotropy in Directional Solidification

Two new classes of growth morphologies, called doublons and seaweed, were simulated using a phase-field method. The evolution of doublon and seaweed morphologies was obtained in directional solidification. The influence of orientation and velocity on the growth morphology was investigated. It was indicated that doublons preferred growing with its crystallographic axis aligned with the heat flow direction. Seaweed, on the other hand, could be obtained by tilting the crystalline axis to 45°. Stable doublons could only exist in a range of velocity regime. Beyond this regime the patterns formed would be unstable. The simulation results agreed with the reported experimental results qualitatively.     

Effects of molten material temperatures and coolant temperatures on vapor explosion

An observable experiment facility for low-temperature molten materials to be dropped into water was set up in this study to investigate the mechanism of the vapor explosion. The effect of the fuel and coolant interaction (FCI) on the vapor explosion during the severe accidents of a fission nuclear reactor has been studied. The experiment results showed that the molten material temperature has an important effect on the vapor explosion behavior and pressure. The increase of the coolant temperature would decrease the pressure of the vapor explosion.     

Crystallization of μc-Si on plastic substrate by using a pulsed double-frequency YAG laser

Thin film transistors (TFTs) of microcrystalline silicon (μc-Si) can provide higher mobility and stability than that of a-Siand better uniformity than that of poly-Si TFTs,and it would be more suitable to be applied to larger-area AMOLEDs.By using 2ωYAG laser annealing,crystalline μc-Si thin film on plastic substrate has been investigated and the proper laser energy needed for crystallization has been indicated.It has been found that the dehydrogenation process at 300-450℃ for a few of hours could be omitted by decreasing the H content in the crystallization precursor,which is suitable for laser crystallization on plastic substrates.The crystalline volume fraction (Xc) and the grain size of the resulted μc-Si could be adjusted by controlling the laser energy.By this method,the μc-Si on plastic substrate with Xc and grain size is respectively 85% (at the maximum) and 50 nm.     

Gamma-ray attenuation technique for measuring void fraction in horizontal gas-liquid two-phase flow

The measurement of void fraction is of importance to the oil industry and chemical industry. In this article, the principle and mathematical method of determining the void fraction of horizontal gas-liquid flow by using a single-energy γ-ray system is described. The γ-ray source is the radioactive isotope of 241Am with γ-ray energy of 59.5 keV. The time-averaged value of the void fraction in a 50.0-mm i.d. transparent horizontal pipeline is measured under various combinations of the liquid flow and gas flow. It is found that increasing the gas flow rate at a fixed liquid flow rate would increase the void fraction. Test data are compared with the predictions of the correlations and a good agreement is found. The result shows that the designed γ-ray system can be used for measuring the void fraction in a horizontal gas-liquid two-phase flow with high accuracy.     

脆性材料弹性常数的复合测量法及程序实现

指出了直接测量脆性材料弹性常数带来的困难,提出了复合测量法,详述了数据处理过程,为测量弹性常数找到了一种更为精确的新方法,在此基础上编制了C程序。     

APPLICATION OF FRF ESTIMATOR BASED ON ERRORS.IN-VARIABLES MODEL IN MULTI-INPUT MULTI-OUTPUT VIBRATION CONTROL SYSTEM

The FRF estimator based on the errors-in-variables(EV)model of multi-input multi-output (MIMO)system is presented to reduce the bias error of FRF H1 estimator.The FRF H1 estimator is influenced by the noises in the inputs of the system and generates an under-estimation of the true FRF. The FRF estimator based on the EV model takes into account the errors in both the inputs and outputs of the system and would lead to more accurate FRF estimation.The FRF estimator based on the EV model is applied to the waveform replication on the 6-DOF (degree-of-freedom) hydraulic vibration table.The result shows that it is favorable to improve the control precision of the MIMO vibration control system.