The formation mechanisms and growth kinetics of Al3 Ni and Al3Ni2 in Ni-Al diffusion couple prepared by electrodeposition of Ni on Al substrate were investigated. The nickel coating with 20 μm thickness was applied o...The formation mechanisms and growth kinetics of Al3 Ni and Al3Ni2 in Ni-Al diffusion couple prepared by electrodeposition of Ni on Al substrate were investigated. The nickel coating with 20 μm thickness was applied on 6061 aluminum alloy by direct current electroplating. The samples were then heat-treated for different durations at 450, 500 and 550 °C under argon atmosphere. The intermetallic phases were identified by means of scanning electron microscopy（SEM）, energy dispersive spectrometry（EDS） and X-ray diffraction（XRD）. The results showed that the formation of intermetallic phases consisted of two important steps. The first step was the lateral growth of intermetallic phase from separate sites, resulting in the formation of a continuous layer. The second step was the growth of the continuous intermetallic layer in the direction perpendicular to the interface. However, excessive increase in thickness of intermetallic phases led to the detachment of reaction products, i.e., Al3 Ni and Al3Ni2, from the substrate. It was also observed that aluminum was the dominant diffusing element during Al3 Ni growth, while nickel diffusion was dominant during Al3Ni2 growth. The growth kinetics of both Al3 Ni and Al3Ni2 phases obeyed a parabolic law.展开更多
Cold-rolled Ti/Al laminated composites were annealed at 525−625℃for 0−128 h,and the interfacial microstructure evolution was investigated.The results indicate that only the TiAl_(3) phase was formed at the Ti/Al inte...Cold-rolled Ti/Al laminated composites were annealed at 525−625℃for 0−128 h,and the interfacial microstructure evolution was investigated.The results indicate that only the TiAl_(3) phase was formed at the Ti/Al interface;most of TiAl_(3) grains were fine equiaxed with average sizes ranging from hundreds of nanometers to several microns and the TiAl_(3) grain size increased with increasing annealing time and/or temperature,but the effect of annealing temperature on the TiAl_(3) grain size was far greater than that of annealing time.The growth of the TiAl_(3) phase consisted of two stages.The initial stage was governed by chemical reaction with a reaction activation energy of 195.75 kJ/mol,and the reaction rate constant of the TiAl_(3) phase was larger as the Ti/Al interface was bonded with fresh surfaces.At the second stage,the growth was governed by diffusion,the diffusion activation energy was 33.69 kJ/mol,and the diffusion growth rate constant of the TiAl_(3) phase was mainly determined by the grain boundary diffusion owing to the smaller TiAl_(3) grain size.展开更多
This paper studies the technics of reducing item exposure by utilizing automatic item generation methods. Known test item calibration method uses item parameter estimation with the statistical data, collected during e...This paper studies the technics of reducing item exposure by utilizing automatic item generation methods. Known test item calibration method uses item parameter estimation with the statistical data, collected during examinees prior testing. Disadvantage of the mentioned item calibration method is the item exposure; when test items become familiar to the examinees. To reduce the item exposure, automatic item generation method is used, where item models are being constructed based on already calibrated test items without losing already estimated item parameters. A technic of item model extraction method from the already calibrated and therefore exposed test items described, which can be used by the test item development specialists to integrate automatic item generation principles with the existing testing applications.展开更多
Due to high price of Straight Vegetable Oil （SVO） for bio-diesel production, the use of Waste Cooking Oil （WCO） will be cost effective. Furthermore, utilization of WCO will refrain waterways pollution and endanger...Due to high price of Straight Vegetable Oil （SVO） for bio-diesel production, the use of Waste Cooking Oil （WCO） will be cost effective. Furthermore, utilization of WCO will refrain waterways pollution and endanger ecosystem. In Malaysia, more than 50-tone of WCO from various sources was produced every day. This study evaluates combustion performance and exhaust emission characteristics of several WCOs with different sources. Modification on fuel properties has been done to improve the combustion and exhaust emission of using WCO as diesel fuel. Regular diesel fuel also has been used for comparison in the test. A 0.6 liter, single-cylinder, air-cooled direct injection diesel engine was used to perform this experiment. Experiment was done at variable engine loads at constant speed.展开更多
Educators and teachers generally agree that a major variable affecting students learning L2 or FL is motivation. This paper discusses the correlation between increasing the sense of achievement and sustaining students...Educators and teachers generally agree that a major variable affecting students learning L2 or FL is motivation. This paper discusses the correlation between increasing the sense of achievement and sustaining students＇ motivations in a Chinese cultural setting, in which language learning should not be understood in terms of North American and Western cultural values. Considering EFL or ElL situations at a tertiary education level in China's Mainland, the author thinks that for university students, we should consider this issue in another way and concludes that, from the adults＇ psychological perspective, the sense of achievement, more than any other factor, plays the most important role in sustaining students＇ motivations, thus contributing greatly to the whole process of learning. Therefore, it should be viewed as a very useful and effective method to maintain students＇ motivations. Based on this idea, the author strongly suggests that while they are capitalizing on some effective methods or strategies to foster and maintain their students＇ motivations, EFL or ElL teachers should try every means and utilize any occasion to ensure that students can feel their achievement and see progress during the advanced level of learning, thus guaranteeing they will keep expending energy and effort in continued learning.展开更多
Applying the theory of adaptation, Feminism, and Performance Studies, this paper explores the adaptation, inter-textuality, and gender in the three films The Tempest （2010） directed by Julie Taymor, Prospero＇s Boo...Applying the theory of adaptation, Feminism, and Performance Studies, this paper explores the adaptation, inter-textuality, and gender in the three films The Tempest （2010） directed by Julie Taymor, Prospero＇s Books （1991） directed by Peter Greenaway, and Shakespeare in Love （1998） directed by John Madden, referenced to Gnomeo and Juliet （2011）, a cartoon animation. Both films of The Tempest show visual spectacle and technology images by CGI （Computer-Generated Cinematic Graphic Image） effect. The author argues the power struggle between Caliban and Prospero played by actress Helen Mirren, changes from post-colonial discourse in the male domain, to be more about the intellect contest between man and woman, and Taymor＇s adaptation is more focused on maternity than actor John Gielgud＇s on politics. Inter-textuality exists in Shakespeare in Love and Shakespeare＇s Romeo and Juliet, and Twelfth Night. Unlike the tragedy in the films, Gnomeo and Juliet ends happily as we can expect from most musicals and fairy tales. The inter-textuality of literature and art, dramatic plays, historical events, and biographical sketches are delicately intertwined. Media represent Shakespeare applied by Jean Baudrillard＇s ＂simulacra＂ and Richard Schechner＇s ＂simulation＂ to present the liminal threshold between reality, role-playing, and theatricality. Shakespeare represented by media rise to visual narratives.展开更多
Energy requirements for tertiary educational purpose is burgeoning, a reflection of its criticality to human asset formation and to use self auto-generation by petrol or diesel generators as the energy supply source i...Energy requirements for tertiary educational purpose is burgeoning, a reflection of its criticality to human asset formation and to use self auto-generation by petrol or diesel generators as the energy supply source is an unsustainable practice. The situation is worrisome in view of the noise pollution and nuisance that constitutes to the learning environment. This paper, therefore, determines the quantity of self generated energy supply, its intensity, the associated CO2 emissions and their possible implications for human capital development. A survey of generating sets was conducted using the University of Nigeria Nsukka as a representative of Nigerian universities. A walk-through-approach was adopted in gathering data and two metrics-life cycle cost and cost of electricity from auto-generation were used to determine the economic implications of the self generation. The results show that self auto-generation contributed installed energy capacity of amount 19 MVA, 20 MVA, 34 MVA, 11 MVA and 22 MVA to run human capital development activities, respectively for academic sessions from July 2006 to November 2010. The study helps us understand that reforms in educational sector are not effective as long as energy insecurity is a dominant factor.展开更多
Objective: To investigate the effect of recombinant human basic fibroblast growth factor ( rhbFGF) on angiogenesis during mandible fracture healing in rabbit.Methods: Fifty adult white rabbits were used for animal mod...Objective: To investigate the effect of recombinant human basic fibroblast growth factor ( rhbFGF) on angiogenesis during mandible fracture healing in rabbit.Methods: Fifty adult white rabbits were used for animal model and randomly divided into a control group (25 rabbits) and an experimental group (25 rabbits). The membranous complex of rhbFGF and bovine type I collagen was prepared and implanted into the rabbit mandible fracture site under periosteum. The animals were sacrificed on 7, 14, 28, 56 and 84 days respectively after operation and the whole mandibles were harvested. The expression of factor Vm related antigen (F8-RA) in callus was examined with immimohistochemical staining.Results: The amounts of microvascular formation in calluses in the rhbFGF-treating group on days 7, 14, 28 and 56 were more than those of the control group (P < 0.01).Conclusions: The results indicated that rhbFGF could stimulate microvascular formation during mandible fracture healing in rabbits.展开更多
文摘The formation mechanisms and growth kinetics of Al3 Ni and Al3Ni2 in Ni-Al diffusion couple prepared by electrodeposition of Ni on Al substrate were investigated. The nickel coating with 20 μm thickness was applied on 6061 aluminum alloy by direct current electroplating. The samples were then heat-treated for different durations at 450, 500 and 550 °C under argon atmosphere. The intermetallic phases were identified by means of scanning electron microscopy（SEM）, energy dispersive spectrometry（EDS） and X-ray diffraction（XRD）. The results showed that the formation of intermetallic phases consisted of two important steps. The first step was the lateral growth of intermetallic phase from separate sites, resulting in the formation of a continuous layer. The second step was the growth of the continuous intermetallic layer in the direction perpendicular to the interface. However, excessive increase in thickness of intermetallic phases led to the detachment of reaction products, i.e., Al3 Ni and Al3Ni2, from the substrate. It was also observed that aluminum was the dominant diffusing element during Al3 Ni growth, while nickel diffusion was dominant during Al3Ni2 growth. The growth kinetics of both Al3 Ni and Al3Ni2 phases obeyed a parabolic law.
基金the financial supports from the S&T Program of Hebei Province,China(No.20373901D)the National Natural Science Foundation of China(Nos.51807047,51804095)+2 种基金the National Science Foundation of Hebei Province,China(No.E2019402433)the Youth Top Talents Science and Technology Research Project of Hebei Province University,China(No.BJ2019003)the Research and Development Project of Science and Technology of Handan City,China(No.19422111008-19).
文摘Cold-rolled Ti/Al laminated composites were annealed at 525−625℃for 0−128 h,and the interfacial microstructure evolution was investigated.The results indicate that only the TiAl_(3) phase was formed at the Ti/Al interface;most of TiAl_(3) grains were fine equiaxed with average sizes ranging from hundreds of nanometers to several microns and the TiAl_(3) grain size increased with increasing annealing time and/or temperature,but the effect of annealing temperature on the TiAl_(3) grain size was far greater than that of annealing time.The growth of the TiAl_(3) phase consisted of two stages.The initial stage was governed by chemical reaction with a reaction activation energy of 195.75 kJ/mol,and the reaction rate constant of the TiAl_(3) phase was larger as the Ti/Al interface was bonded with fresh surfaces.At the second stage,the growth was governed by diffusion,the diffusion activation energy was 33.69 kJ/mol,and the diffusion growth rate constant of the TiAl_(3) phase was mainly determined by the grain boundary diffusion owing to the smaller TiAl_(3) grain size.
文摘This paper studies the technics of reducing item exposure by utilizing automatic item generation methods. Known test item calibration method uses item parameter estimation with the statistical data, collected during examinees prior testing. Disadvantage of the mentioned item calibration method is the item exposure; when test items become familiar to the examinees. To reduce the item exposure, automatic item generation method is used, where item models are being constructed based on already calibrated test items without losing already estimated item parameters. A technic of item model extraction method from the already calibrated and therefore exposed test items described, which can be used by the test item development specialists to integrate automatic item generation principles with the existing testing applications.
文摘Due to high price of Straight Vegetable Oil （SVO） for bio-diesel production, the use of Waste Cooking Oil （WCO） will be cost effective. Furthermore, utilization of WCO will refrain waterways pollution and endanger ecosystem. In Malaysia, more than 50-tone of WCO from various sources was produced every day. This study evaluates combustion performance and exhaust emission characteristics of several WCOs with different sources. Modification on fuel properties has been done to improve the combustion and exhaust emission of using WCO as diesel fuel. Regular diesel fuel also has been used for comparison in the test. A 0.6 liter, single-cylinder, air-cooled direct injection diesel engine was used to perform this experiment. Experiment was done at variable engine loads at constant speed.
文摘Educators and teachers generally agree that a major variable affecting students learning L2 or FL is motivation. This paper discusses the correlation between increasing the sense of achievement and sustaining students＇ motivations in a Chinese cultural setting, in which language learning should not be understood in terms of North American and Western cultural values. Considering EFL or ElL situations at a tertiary education level in China's Mainland, the author thinks that for university students, we should consider this issue in another way and concludes that, from the adults＇ psychological perspective, the sense of achievement, more than any other factor, plays the most important role in sustaining students＇ motivations, thus contributing greatly to the whole process of learning. Therefore, it should be viewed as a very useful and effective method to maintain students＇ motivations. Based on this idea, the author strongly suggests that while they are capitalizing on some effective methods or strategies to foster and maintain their students＇ motivations, EFL or ElL teachers should try every means and utilize any occasion to ensure that students can feel their achievement and see progress during the advanced level of learning, thus guaranteeing they will keep expending energy and effort in continued learning.
文摘Applying the theory of adaptation, Feminism, and Performance Studies, this paper explores the adaptation, inter-textuality, and gender in the three films The Tempest （2010） directed by Julie Taymor, Prospero＇s Books （1991） directed by Peter Greenaway, and Shakespeare in Love （1998） directed by John Madden, referenced to Gnomeo and Juliet （2011）, a cartoon animation. Both films of The Tempest show visual spectacle and technology images by CGI （Computer-Generated Cinematic Graphic Image） effect. The author argues the power struggle between Caliban and Prospero played by actress Helen Mirren, changes from post-colonial discourse in the male domain, to be more about the intellect contest between man and woman, and Taymor＇s adaptation is more focused on maternity than actor John Gielgud＇s on politics. Inter-textuality exists in Shakespeare in Love and Shakespeare＇s Romeo and Juliet, and Twelfth Night. Unlike the tragedy in the films, Gnomeo and Juliet ends happily as we can expect from most musicals and fairy tales. The inter-textuality of literature and art, dramatic plays, historical events, and biographical sketches are delicately intertwined. Media represent Shakespeare applied by Jean Baudrillard＇s ＂simulacra＂ and Richard Schechner＇s ＂simulation＂ to present the liminal threshold between reality, role-playing, and theatricality. Shakespeare represented by media rise to visual narratives.
文摘Energy requirements for tertiary educational purpose is burgeoning, a reflection of its criticality to human asset formation and to use self auto-generation by petrol or diesel generators as the energy supply source is an unsustainable practice. The situation is worrisome in view of the noise pollution and nuisance that constitutes to the learning environment. This paper, therefore, determines the quantity of self generated energy supply, its intensity, the associated CO2 emissions and their possible implications for human capital development. A survey of generating sets was conducted using the University of Nigeria Nsukka as a representative of Nigerian universities. A walk-through-approach was adopted in gathering data and two metrics-life cycle cost and cost of electricity from auto-generation were used to determine the economic implications of the self generation. The results show that self auto-generation contributed installed energy capacity of amount 19 MVA, 20 MVA, 34 MVA, 11 MVA and 22 MVA to run human capital development activities, respectively for academic sessions from July 2006 to November 2010. The study helps us understand that reforms in educational sector are not effective as long as energy insecurity is a dominant factor.
基金This study was supported by the National Natural Science Foundation of China,No.59975074.
文摘Objective: To investigate the effect of recombinant human basic fibroblast growth factor ( rhbFGF) on angiogenesis during mandible fracture healing in rabbit.Methods: Fifty adult white rabbits were used for animal model and randomly divided into a control group (25 rabbits) and an experimental group (25 rabbits). The membranous complex of rhbFGF and bovine type I collagen was prepared and implanted into the rabbit mandible fracture site under periosteum. The animals were sacrificed on 7, 14, 28, 56 and 84 days respectively after operation and the whole mandibles were harvested. The expression of factor Vm related antigen (F8-RA) in callus was examined with immimohistochemical staining.Results: The amounts of microvascular formation in calluses in the rhbFGF-treating group on days 7, 14, 28 and 56 were more than those of the control group (P < 0.01).Conclusions: The results indicated that rhbFGF could stimulate microvascular formation during mandible fracture healing in rabbits.
