Microstructure and impact mechanical properties of multi-layer and multi-pass TIG welded joints of Al-Zn-Mg alloy plates

The microstructure and mechanical properties of multi-layer multi-pass TIG welded joints of Al-Zn-Mg alloy plates were studied.The phase constituent and microstructure of different regions of the welded joints were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),transmission electron microscopy(TEM)and energy disperse spectrum(EDS),while the mechanical properties were evaluated according to the impact test.A dispersively distributed spherical and needle-likeη(MgZn2)phase was obtained in the welding seam.The phase composition of the heat-affected zone(HAZ)wasα(Al)+η(MgZn2)+Al6Mn,and there were a large number of dispersively precipitated nanoscale particles.The welded joint zone had the highest impact toughness as compared with the other parts of the joint.The MgZn2 phase in the weld zone contributed to the improved toughness of the joint.Al2 MgCu phase in HAZ was proven to act as a crack source during fracture.

Bayesian-Based Speckle Suppression for SAR Image Using Contourlet Transform

A novel and efficient speckle noise reduction algorithm based on Bayesian contourlet shrinkage using contourlet transform is proposed.First,we show the sub-band decompositions of SAR images using contourle transforms,which provides sparse representation at both spatial and directional resolutions.Then,a Bayesian contourlet shrinkage factor is applied to the decomposed data to estimate the best value for noise-free contourle coefficients.Experimental results show that compared with conventional wavelet despeckling algorithm,the proposed algorithm can achieve an excellent balance between suppresses speckle effectively and preserve image details,and the significant information of origina image like textures and contour details is well ma intained.

An Immunoabsorption Column Configuration for Hepatitis B Virus

Objective To conifgure an immunoabsorption column for hepatitis B virus. Methods Being activated by epichlorohydrin, the human antibody HBsAb-IgG was bound to the carrier of agarose gel. The configuration process was as follows: the synthesis of epoxide matrix, the synthesis and activation of amino matrix, the synthesis of aldehydic matrix, the synthesis of immunoabsorption matrix, the end capping and reduction of unbound aldehydic, the blocking of unbound mass and the iflling of the column. Results The bound rate of activated agarose gel and antibody HBsAb-IgG is 85.07%. By plasma adsorption experiment, it is revealed that the immunoabsorption column can absorb and eliminate 58.97%of HBsAg and 53.1%of hepatitis B virus particles in extracorporeal plasma. Conclusions The immunoabsorption column for hepatitis B virus can absorb and eliminate HBsAg and hepatitis B virus particles in extracorporeal plasma.

Clinical Characteristics and Treatment for Patients with Occult Chronic Hepatitis B

Objective To observe the clinical manifestations and assess direct antiviral effect for patients with occult hepatitis B in China.Methods The study includes 15 patients with occult hepatitis B and their medical history,family history,firstdiagnosis time,confirmed-diagnosis time,laboratory report,anti-viral therapy and outcomes were analyzed.Results The average age of the patients is 38.67-year old(6 males and 9 females),2 with acute hepatitis B(2/15,13.3%),13 with no hepatitis history(13/15,86.6%),8 with family history(8/15,53.3%),6 with no family history(6/15,40%),1 with unknown family history(1/15,6.6%).Eight patients were treated with entecavir(0.5 mg/day,taken orally),with effective results and steady conditions;3 patients were treated with lamivudine(0.1 g/day,taken orally),2 of them were prescribed to take adefovir dipivoxil additionally due to drug-resistance,the other one was treated with lamivudine continuously without drug-resistance;4 cases refused anti-viral therapy.One patient’s condition remained steady,1 patient died of cirrhosis with portal hypertension and liver failure 5 years after firstdiagnosis,1 patient progressed to hepatocellular carcinoma and accepted surgery operation treatment 5 years after first-diagnosis,the other 1 patient progressed to compensatory cirrhosis 2 years after first-diagnosis and is steady from then,which indicates that occult chronic hepatitis B can progress to cirrhosis and hepatocellular carcinoma without therapy in time.Conclusions The clinical characteristics of 15 cases with occult chronic hepatitis B showed that these patients with short latency,younger age when being-struck,and light damage to liver function.The efficacy and drugresistance of nucleos(t)ide-analogue(entecavir,lamivudine,adefovir dipivoxil)in treatment of patients with occult chronic hepatitis B are similar to chronic hepatitis B.

Medical X-Ray Image Enhancement Based on Kramer's PDE Model

The purpose of this study is to present an application of a novel enhancement technique for enhancing medical images generated from X-rays. The method presented in this study is based on a nonlinear partial differential equation （PDE） model, Kramer＇s PDE model. The usefulness of this method is investigated by experimental results. We apply this method to a medical X-ray image. For comparison, the X-ray image is also processed using classic Perona-Malik PDE model and Catte PDE model. Although the Perona-Malik model and Catte PDE model could also enhance the image, the quality of the enhanced images is considerably inferior compared with the enhanced image using Kramer＇s PDE model. The study suggests that the Kramer＇s PDE model is capable of enhancing medical X-ray images, which will make the X-ray images more reliable.