The influence of Ti-Si-Mg-AI wire on microstructure and mechanical properties of SiCp/A1 metal matrix composite joints produced by plasma arc in-situ weld-alloying was investigated. Argon-nitrogen mixture was used as ...The influence of Ti-Si-Mg-AI wire on microstructure and mechanical properties of SiCp/A1 metal matrix composite joints produced by plasma arc in-situ weld-alloying was investigated. Argon-nitrogen mixture was used as plasma gas and Ti-Si-Mg-A1 flux-cored wires as filled composites. Weldments were submitted to tensile test. Meanwhile, the macro morphology and microstructure of the joints were examined. The result shows that the formation ofneedie-like harmful phase A14C3 is effectively inhibited and the wettability of molten pool is improved by adding Ti-Si-Mg-A1 flux-cored wires. With 15Ti-5Si-5Mg-A1 flux-cored wire as filled composite, the maximum tensile strength of the welded joint is 267 MPa, which is up to 83% that of the matrix composites under annealed condition.展开更多
In the paper, the effects of linear expansion coefficient and basic index of melting slag on the detachability of self shielded flux cored electrode (SSFCE) are investigated. An equation is obtained on the principles ...In the paper, the effects of linear expansion coefficient and basic index of melting slag on the detachability of self shielded flux cored electrode (SSFCE) are investigated. An equation is obtained on the principles of ceramics and mineralography which predict the detachability of basic SSFCE. In addition, stick slag mechanism of SSFCE is analyzed.展开更多
To investigate influence of welding parameters on weld bead geometry in underwater wet flux cored arc welding (FCAW), orthogonal experiments of underwater wet FCAW were conducted in the hyperbaric chamber at water d...To investigate influence of welding parameters on weld bead geometry in underwater wet flux cored arc welding (FCAW), orthogonal experiments of underwater wet FCAW were conducted in the hyperbaric chamber at water depth from 0.2 m to 60 m and mathematical models were developed by multiple curvilinear regression method from the experimental data. Sensitivity analysis was then performed to predict the bead geometry and evaluate the influence of welding parameters. The results reveal that water depth has a greater influence on bead geometry than other welding parameters when welding at a water depth less than 10 m. At a water depth deeper than 10 m, a change in travel speed affects the bead geometry more strongly than other welding parameters.展开更多
By measuring the content of oxygen and nitrogen in welds of six kinds of self-shielded flux-cored wires,the effect of oxygen on nitrogen content in weld is studied and the different absorptive mechanisms of nitrogen a...By measuring the content of oxygen and nitrogen in welds of six kinds of self-shielded flux-cored wires,the effect of oxygen on nitrogen content in weld is studied and the different absorptive mechanisms of nitrogen at a low oxygen level([O] lower than 0.02%) and a high oxygen level ([O] higher than 0.03%) have been discovered.The results indicate that the content of nitrogen in weld can be made lowest by modifying the composition of flux and controlling the content of oxygen to the range of 0.02%~0.03%.展开更多
A set of electromagnetic vibration powder feeding apparatus of the flux cored wire production line and its single chip controlling system have been designed in this paper. The parameters of the electromagnatic vibr...A set of electromagnetic vibration powder feeding apparatus of the flux cored wire production line and its single chip controlling system have been designed in this paper. The parameters of the electromagnatic vibration powder feeding apparatus have been tested, the functional relation between powder feeding velocity V L and current I has been made out so that the controlling system can not only automatically make out the quantity of the powder according to the width of the steel belt, powder density, production speed and filling ratio, but also adjust the powder feeding speed according to the real production speed, keeping a stable filling ratio.展开更多
Because of the high requirement of quality,vile working environment and great difficulty of automatic welding,MMAW is usually adopted for the welding of the platform jacket and the pile pipe.Its low efficiency and har...Because of the high requirement of quality,vile working environment and great difficulty of automatic welding,MMAW is usually adopted for the welding of the platform jacket and the pile pipe.Its low efficiency and hard working is one of the choke points for construction progress. In this article,an up-to-date technology for platform pile pipe welding was introduced. Cored with FCW-S and combined with the characters and requirements of platform construction,the special automatic horizontal welding equipment and process were developed. Further more,the offshore application were introduced too.展开更多
This study was focused on wear-resistant material prepared by CO2 GMAW method to basically determine the alloys and hardfacing technology which could be employed into mining equipment. Three flux-cored wires with diff...This study was focused on wear-resistant material prepared by CO2 GMAW method to basically determine the alloys and hardfacing technology which could be employed into mining equipment. Three flux-cored wires with different chemical compositions, marked by DM-I, DM-II and DM-III were used in welding a martensitic steel for the comparison of the microstructures and mechanical properties of the welding metals and HAZ. The results show that DM-I weld metal contains martensite plus other reinforced phases, while both DM-II and DM-III alloys lead to mainly martensitic microstructures with little precipitates. Among all of the tested materials the DM-I alloy has the highest hardness and wear resistance but the lowest impact toughness among the experimental weld metals. Meanwhile, the hardness, impact toughness and wear resistance of the DM-II and DM-III alloys are close to those of the base metal but the DM-III is not as strong as DM-II. Dimples can be found on the impact fracture of the weld metals, but the steel fracture consists of both cleavage and dimples. Thus HAZ has less risk for cracking than the welds, and the DM-II wire which produces the weld having identical mechanical properties to the base metal is suitable for further application.展开更多
MCC (micro crystalline cellulose) is a very important product in pharmaceuticals, foods, cosmetics and other industries. MCC can be made from any natural cellulose materials that have high content of cellulose rangi...MCC (micro crystalline cellulose) is a very important product in pharmaceuticals, foods, cosmetics and other industries. MCC can be made from any natural cellulose materials that have high content of cellulose ranging from pure cellulose, commercial grade cellulose to lignocellulosic materials. In this work, Beeswing (-20 L) and Chaff (5/8) which are the parts of corn cobs were used as raw materials to produce MCC via alkaline degradation, bleaching and hydrolysis. The optimum conditions of alkaline degradation, bleaching and hydrolysis were studied. MCC samples that prepared from -20 L and 5/8 were characterized through XRD (X-ray diffraction), SEM (scanning electron microscopy) and compared with the commercial MCC (Avicel PH 101). The results show that the degree of crystallinity of alkaline degradation, bleaching and hydrolysis obtained at 10% of NaOH 95 ~C for 2 h, NaCIO21.5 g 10% of acetic acid 0.5 mL 70 ~C for 2 h, 2 N of HC1, 105 ~C for 1 h showed maximum values which are 77.07%, 75.07% and 86.84%, respectively. The degree of crystallinity and the morphology of prepared MCC correspond to that of Avicel PH 101 industrial investment has been studied, the benefits of micro crystalline cellulose production (MCC) is 3,447 baht/kg. The investment of the plant is 7,263,514 baht and the breakeven point is around 6 years.展开更多
In pre-clinical phase of new drug development,it is particularly important to establish an in vitro model to mimic the metabolism situation of human body.The aim of the in vitro model is to reduce the usage of experim...In pre-clinical phase of new drug development,it is particularly important to establish an in vitro model to mimic the metabolism situation of human body.The aim of the in vitro model is to reduce the usage of experimental animals and to make a more accurate prediction of the drug metabolism in vivo.Microfluidic chip is an emerging technology to establish predictive models.By integrating subcellular fractions,hepatocytes or liver tissue in the microfluidic chips,more predictive in vitro metabolism models can be established for drug development.The microfluidic platform offers dynamic and controlled fluids,as well as sophisticated liver tissue assembly to remodel the physiological and pathological microenvironment of liver in the human body.This review updates the microfluidic-based liver drug metabolism models since 2011,and summarizes the development of different models based on different chip vectors(subcellular components,primary hepatocytes,and tissue sections).It serves as a guide for newcomers to this dynamic field.展开更多
基金Project (09003) supported by the Open-Fund Research of State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,ChinaProject (JD0805) supported by the Science and Technology Innovation Team,Jiangsu University,China
文摘The influence of Ti-Si-Mg-AI wire on microstructure and mechanical properties of SiCp/A1 metal matrix composite joints produced by plasma arc in-situ weld-alloying was investigated. Argon-nitrogen mixture was used as plasma gas and Ti-Si-Mg-A1 flux-cored wires as filled composites. Weldments were submitted to tensile test. Meanwhile, the macro morphology and microstructure of the joints were examined. The result shows that the formation ofneedie-like harmful phase A14C3 is effectively inhibited and the wettability of molten pool is improved by adding Ti-Si-Mg-A1 flux-cored wires. With 15Ti-5Si-5Mg-A1 flux-cored wire as filled composite, the maximum tensile strength of the welded joint is 267 MPa, which is up to 83% that of the matrix composites under annealed condition.
文摘In the paper, the effects of linear expansion coefficient and basic index of melting slag on the detachability of self shielded flux cored electrode (SSFCE) are investigated. An equation is obtained on the principles of ceramics and mineralography which predict the detachability of basic SSFCE. In addition, stick slag mechanism of SSFCE is analyzed.
基金Projects(51175185,50705030)supported by the National Natural Science Foundation of ChinaProject(2012ZZ0052)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(9151064101000065)supported by the Natural Science Foundation of Guangdong Province,China
文摘To investigate influence of welding parameters on weld bead geometry in underwater wet flux cored arc welding (FCAW), orthogonal experiments of underwater wet FCAW were conducted in the hyperbaric chamber at water depth from 0.2 m to 60 m and mathematical models were developed by multiple curvilinear regression method from the experimental data. Sensitivity analysis was then performed to predict the bead geometry and evaluate the influence of welding parameters. The results reveal that water depth has a greater influence on bead geometry than other welding parameters when welding at a water depth less than 10 m. At a water depth deeper than 10 m, a change in travel speed affects the bead geometry more strongly than other welding parameters.
文摘By measuring the content of oxygen and nitrogen in welds of six kinds of self-shielded flux-cored wires,the effect of oxygen on nitrogen content in weld is studied and the different absorptive mechanisms of nitrogen at a low oxygen level([O] lower than 0.02%) and a high oxygen level ([O] higher than 0.03%) have been discovered.The results indicate that the content of nitrogen in weld can be made lowest by modifying the composition of flux and controlling the content of oxygen to the range of 0.02%~0.03%.
文摘A set of electromagnetic vibration powder feeding apparatus of the flux cored wire production line and its single chip controlling system have been designed in this paper. The parameters of the electromagnatic vibration powder feeding apparatus have been tested, the functional relation between powder feeding velocity V L and current I has been made out so that the controlling system can not only automatically make out the quantity of the powder according to the width of the steel belt, powder density, production speed and filling ratio, but also adjust the powder feeding speed according to the real production speed, keeping a stable filling ratio.
文摘Because of the high requirement of quality,vile working environment and great difficulty of automatic welding,MMAW is usually adopted for the welding of the platform jacket and the pile pipe.Its low efficiency and hard working is one of the choke points for construction progress. In this article,an up-to-date technology for platform pile pipe welding was introduced. Cored with FCW-S and combined with the characters and requirements of platform construction,the special automatic horizontal welding equipment and process were developed. Further more,the offshore application were introduced too.
文摘This study was focused on wear-resistant material prepared by CO2 GMAW method to basically determine the alloys and hardfacing technology which could be employed into mining equipment. Three flux-cored wires with different chemical compositions, marked by DM-I, DM-II and DM-III were used in welding a martensitic steel for the comparison of the microstructures and mechanical properties of the welding metals and HAZ. The results show that DM-I weld metal contains martensite plus other reinforced phases, while both DM-II and DM-III alloys lead to mainly martensitic microstructures with little precipitates. Among all of the tested materials the DM-I alloy has the highest hardness and wear resistance but the lowest impact toughness among the experimental weld metals. Meanwhile, the hardness, impact toughness and wear resistance of the DM-II and DM-III alloys are close to those of the base metal but the DM-III is not as strong as DM-II. Dimples can be found on the impact fracture of the weld metals, but the steel fracture consists of both cleavage and dimples. Thus HAZ has less risk for cracking than the welds, and the DM-II wire which produces the weld having identical mechanical properties to the base metal is suitable for further application.
文摘MCC (micro crystalline cellulose) is a very important product in pharmaceuticals, foods, cosmetics and other industries. MCC can be made from any natural cellulose materials that have high content of cellulose ranging from pure cellulose, commercial grade cellulose to lignocellulosic materials. In this work, Beeswing (-20 L) and Chaff (5/8) which are the parts of corn cobs were used as raw materials to produce MCC via alkaline degradation, bleaching and hydrolysis. The optimum conditions of alkaline degradation, bleaching and hydrolysis were studied. MCC samples that prepared from -20 L and 5/8 were characterized through XRD (X-ray diffraction), SEM (scanning electron microscopy) and compared with the commercial MCC (Avicel PH 101). The results show that the degree of crystallinity of alkaline degradation, bleaching and hydrolysis obtained at 10% of NaOH 95 ~C for 2 h, NaCIO21.5 g 10% of acetic acid 0.5 mL 70 ~C for 2 h, 2 N of HC1, 105 ~C for 1 h showed maximum values which are 77.07%, 75.07% and 86.84%, respectively. The degree of crystallinity and the morphology of prepared MCC correspond to that of Avicel PH 101 industrial investment has been studied, the benefits of micro crystalline cellulose production (MCC) is 3,447 baht/kg. The investment of the plant is 7,263,514 baht and the breakeven point is around 6 years.
基金National Natural Science Foundation of China(Grant No.81573684 and 81530097)Beijing Municipal Science and Technology Project(Grant No.Z181100002218028)National Key Technology R&D Program “New Drug Innovation” of China(Grant No.2018ZX09711001-008-003)
文摘In pre-clinical phase of new drug development,it is particularly important to establish an in vitro model to mimic the metabolism situation of human body.The aim of the in vitro model is to reduce the usage of experimental animals and to make a more accurate prediction of the drug metabolism in vivo.Microfluidic chip is an emerging technology to establish predictive models.By integrating subcellular fractions,hepatocytes or liver tissue in the microfluidic chips,more predictive in vitro metabolism models can be established for drug development.The microfluidic platform offers dynamic and controlled fluids,as well as sophisticated liver tissue assembly to remodel the physiological and pathological microenvironment of liver in the human body.This review updates the microfluidic-based liver drug metabolism models since 2011,and summarizes the development of different models based on different chip vectors(subcellular components,primary hepatocytes,and tissue sections).It serves as a guide for newcomers to this dynamic field.