The corrosion behaviors of hafnium in Et4NBr isopropanol and acetonitrile(ACN)solutions were investigated usingelectrochemical measurements,ICP-AES and SEM techniques.Results revealed that the open circuit potential g...The corrosion behaviors of hafnium in Et4NBr isopropanol and acetonitrile(ACN)solutions were investigated usingelectrochemical measurements,ICP-AES and SEM techniques.Results revealed that the open circuit potential gets more positive dueto the increased passivity of the surface oxide film with increasing immersion time until it reaches a steady state value.Thepotentiodynamic anodic polarization curves did not exhibit an active dissolution region near corrosion potential due to the presenceof an oxide film on the electrode surface,which was followed by pitting corrosion.SEM images confirmed the existence of pits onthe electrode surface.Cyclic voltammetry and galvanostatic measurements allowed the pitting potential(φpit)and the repassivationpotential(φp)to be determined.φpit increased with increasing potential scanning rate but decreased with increasing temperature,Br-concentration and ACN concentration.The impedance spectra showed that the resistances of the solution and charge transferdecreased with the increase of ACN concentration.展开更多
The outpatient-based study by Deng et al [World J Gastroenterol 2011 July 14; 17(26): 3133-3139] on the factors that may influence the colorectal cancer (CRC) screening feasibility, encouraged our curiosity. Establish...The outpatient-based study by Deng et al [World J Gastroenterol 2011 July 14; 17(26): 3133-3139] on the factors that may influence the colorectal cancer (CRC) screening feasibility, encouraged our curiosity. Establishing a simple method for quickly assessing the educational level of patients and modulating a questionnaire for each type of patient, may be an effective protocol to increase the people participation, mainly in countries where sufficient medical resources and financial support are lacking. In fact, the knowledge directly affects the feasibility when screening is offered. Patient educational level influences the understanding of the knowledge and the screening method. This factor may affect patient's priority level on the study participation, the understanding of questions, and the motivation to complete the questionnaire and, consequently, the screening success. Recent studies have found a relationship between high educational level and CRC screening participation, and emphasized the question-naire ineffectiveness in the illiterate people. Although the questionnaire is an excellent method for this kind of evaluation, physician's contribution could be the most important factor associated with the screening method. Thus, further studies should be conducted to explore the compliance of patients with low educational level and to look for the best solutions for their enrollment.展开更多
Group discussions are very important in oral English classes. It maximizes students＇ speaking time in a specified-time period. Group discussions have a strong positive effect on the atmosphere in the classroom and th...Group discussions are very important in oral English classes. It maximizes students＇ speaking time in a specified-time period. Group discussions have a strong positive effect on the atmosphere in the classroom and the behaviors of the students as they can get more ideas from their friends, and sometimes students don＇t even understand the topic for discussion but by interacting with others they can understand the topic. Particularly it is a good warm-up in conversational classes. The most important reason for using group discussions before speaking tasks is to reduce students＇ nervousness of making mistakes. And this encourages students to be more active in speaking class.展开更多
There is a popular notion of teachers that they judge a student according to their score. On this basis, teachers developed a systematical thinking method, perspective and way of act. Currently, teachers arrange seats...There is a popular notion of teachers that they judge a student according to their score. On this basis, teachers developed a systematical thinking method, perspective and way of act. Currently, teachers arrange seats and interact with students and do many other things according to their score sub-consciously. This phenomenon, however, has a long-standing basis on which the school evaluates teachers and teachers evaluate themselves.展开更多
The elastic behavior of the polymer chain was investigated in a three-dimensional off-lattice model. We sample more than 109 conformations of each kind of polymer chain by using a Monte Carlo algorithm, then analyze t...The elastic behavior of the polymer chain was investigated in a three-dimensional off-lattice model. We sample more than 109 conformations of each kind of polymer chain by using a Monte Carlo algorithm, then analyze them with the non-Gaussian theory of rubberlike elasticity, and end with a statistical study. Through observing the effect of the chain flexibility and the stretching ratio on the mean-square end-to-end distance, the average energy, the average Helmholtz free energy, the elastic force, the contribution of energy to the elastic force, and the entropy contribution to elastic force of the polymer chain, we find that a rigid polymer chain is much easier to stretch than a flexible polymer chain. Also, a rigid polymer chain will become difficult to stretch only at a quite high stretching ratio because of the effect of the entropy contribution. These results of our simulation calculation may explain some of the macroscopic phenomena of polymer and biomacromolecular elasticity.展开更多
The present study investigates the preferred strategies of the speech act of complaint by Malaysian ESL learners. The subjects were selected from Malaysian university students majoring in English at University Sains M...The present study investigates the preferred strategies of the speech act of complaint by Malaysian ESL learners. The subjects were selected from Malaysian university students majoring in English at University Sains Malaysia. Data were collected through an open-ended questionnaire in the form of a discourse completion task and a semi-structured interview. The responses were analyzed based on Rinnert and Nogami＇s （2006） taxonomy of the speech act of complaint to examine the main components of complaint, the level of directness and the degree of mitigation. It is anticipated that the findings will be able to provide valuable insights into teaching and learning English in non-native settings.展开更多
We propose an aggregation model of a two-species system to mimic the growth of cities＇ population and assets, in which irreversible coagulation reactions and exchange reactions occur between any two aggregates of th...We propose an aggregation model of a two-species system to mimic the growth of cities＇ population and assets, in which irreversible coagulation reactions and exchange reactions occur between any two aggregates of the same species, and the monomer-birth reactions of one species occur by the catalysis Of the other species. In the case with population-catalyzed birth of assets, the rate kernel of an asset aggregate Bκ of size k grows to become an aggregate Bκ＋1 through a monomer-birth catalyzed by a population aggregate Aj of size j is J（κ,j） = Jkjλ. And in mutually catalyzed birth model, the birth rate kernels of population and assets are H（k,j）=Hkjη and J（k,j） = Jkjλ, respectively. The kinetics of the system is investigated based on the mean-field theory. In the model of population-catalyzed birth of aseets, the long-time asymptotic behavior of the assets aggregate size distribution obeys the conventional or modified scaling form. In mutually catalyzed birth system, the asymptotic behaviors of population and assets obey the conventional scaling form in the case of η=λ =0, and they obey the modified scaling form in the case of η=0, λ=1. In the case of η = λ= 1, the total mass of population aggregates and that of asset aggregates both grow much faster than those in population-catalyzed birth of assets model, and they approaches to infinite values in finite time.展开更多
Extended digital image correlation(X-DIC) method is one novel test method in experimental mechanics.In this paper,the principle of the X-DIC method was introduced in detail.A selection scheme of the initial value of N...Extended digital image correlation(X-DIC) method is one novel test method in experimental mechanics.In this paper,the principle of the X-DIC method was introduced in detail.A selection scheme of the initial value of Newton iteration method was proposed when Newton iteration method was applied to solve the partial differential equations.This scheme could make the X-DIC method suitable for the large deformation measurement and avoid the non-convergence phenomenon effectively.The performance of the X-DIC method was verified by simulated images.Since the pixel point with the maximum absolute error occurred mainly at the corner or on the interface of the region of interest(ROI,region used for correlation calculation),measured deformation of the core area(area surrounding the center point of the ROI with a smaller size) was taken as the reliable measured value.The measurement accuracy of the X-DIC method could be improved greatly by using the core area.Combined with a long-distance microscope,the X-DIC method could be used in the deformation measurement of the micro-region.Zero deformation experiment was done to test the precision of the measurement system.Then,the X-DIC method was applied to measure the micro-region deformation of the specimen with a crack.Test value was proved to be in accordance with the actual deformation,showing that the X-DIC method is suitable for the research of microscale mechanical behavior of materials.展开更多
In recent years, there has been a growing interest toward Blast Furnace Gas （BFG） as a low-grade energy source for industrial furnaces. This paper considers the revamping of a galvanic plant furnace converted to BFG...In recent years, there has been a growing interest toward Blast Furnace Gas （BFG） as a low-grade energy source for industrial furnaces. This paper considers the revamping of a galvanic plant furnace converted to BFG from natural gas. In the design of the new system, the ejector on the exhaust line is a critical component. This paper studies the flow behavior of the ejector using a Computational Fluid Dynamics （CFD） analysis. The CFD model is based on a 3D representation of the ejector, using air and exhaust gases as working fluids. This paper is divided in three parts. In the first part, the galvanic plant used as case study is presented and discussed, in the second part the CFD approach is outlined, and in the third part the CFD approach is validated using experimental data and the numerical results are presented and discussed. Different Reynolds-Averaged Navier-Stokes （RANS） turbulence models （k-to SST and k-e Realizable） are evaluated in terms of convergence capability and accuracy in predicting the pressure drop along the ejector. Suggestions for future optimization of the system are also provided.展开更多
基金Project(51374254) supported by the National Natural Science Foundation of China
文摘The corrosion behaviors of hafnium in Et4NBr isopropanol and acetonitrile(ACN)solutions were investigated usingelectrochemical measurements,ICP-AES and SEM techniques.Results revealed that the open circuit potential gets more positive dueto the increased passivity of the surface oxide film with increasing immersion time until it reaches a steady state value.Thepotentiodynamic anodic polarization curves did not exhibit an active dissolution region near corrosion potential due to the presenceof an oxide film on the electrode surface,which was followed by pitting corrosion.SEM images confirmed the existence of pits onthe electrode surface.Cyclic voltammetry and galvanostatic measurements allowed the pitting potential(φpit)and the repassivationpotential(φp)to be determined.φpit increased with increasing potential scanning rate but decreased with increasing temperature,Br-concentration and ACN concentration.The impedance spectra showed that the resistances of the solution and charge transferdecreased with the increase of ACN concentration.
文摘The outpatient-based study by Deng et al [World J Gastroenterol 2011 July 14; 17(26): 3133-3139] on the factors that may influence the colorectal cancer (CRC) screening feasibility, encouraged our curiosity. Establishing a simple method for quickly assessing the educational level of patients and modulating a questionnaire for each type of patient, may be an effective protocol to increase the people participation, mainly in countries where sufficient medical resources and financial support are lacking. In fact, the knowledge directly affects the feasibility when screening is offered. Patient educational level influences the understanding of the knowledge and the screening method. This factor may affect patient's priority level on the study participation, the understanding of questions, and the motivation to complete the questionnaire and, consequently, the screening success. Recent studies have found a relationship between high educational level and CRC screening participation, and emphasized the question-naire ineffectiveness in the illiterate people. Although the questionnaire is an excellent method for this kind of evaluation, physician's contribution could be the most important factor associated with the screening method. Thus, further studies should be conducted to explore the compliance of patients with low educational level and to look for the best solutions for their enrollment.
文摘Group discussions are very important in oral English classes. It maximizes students＇ speaking time in a specified-time period. Group discussions have a strong positive effect on the atmosphere in the classroom and the behaviors of the students as they can get more ideas from their friends, and sometimes students don＇t even understand the topic for discussion but by interacting with others they can understand the topic. Particularly it is a good warm-up in conversational classes. The most important reason for using group discussions before speaking tasks is to reduce students＇ nervousness of making mistakes. And this encourages students to be more active in speaking class.
文摘There is a popular notion of teachers that they judge a student according to their score. On this basis, teachers developed a systematical thinking method, perspective and way of act. Currently, teachers arrange seats and interact with students and do many other things according to their score sub-consciously. This phenomenon, however, has a long-standing basis on which the school evaluates teachers and teachers evaluate themselves.
基金This work was supported by the National Science Fund for Distinguished Young Scholars （No.20525416）, the National Natural Science Foundation of China （No.20490220, No.20374050, and No.90403022）, and the National Basic Research Program of China （No.2005CB623800）.
文摘The elastic behavior of the polymer chain was investigated in a three-dimensional off-lattice model. We sample more than 109 conformations of each kind of polymer chain by using a Monte Carlo algorithm, then analyze them with the non-Gaussian theory of rubberlike elasticity, and end with a statistical study. Through observing the effect of the chain flexibility and the stretching ratio on the mean-square end-to-end distance, the average energy, the average Helmholtz free energy, the elastic force, the contribution of energy to the elastic force, and the entropy contribution to elastic force of the polymer chain, we find that a rigid polymer chain is much easier to stretch than a flexible polymer chain. Also, a rigid polymer chain will become difficult to stretch only at a quite high stretching ratio because of the effect of the entropy contribution. These results of our simulation calculation may explain some of the macroscopic phenomena of polymer and biomacromolecular elasticity.
文摘The present study investigates the preferred strategies of the speech act of complaint by Malaysian ESL learners. The subjects were selected from Malaysian university students majoring in English at University Sains Malaysia. Data were collected through an open-ended questionnaire in the form of a discourse completion task and a semi-structured interview. The responses were analyzed based on Rinnert and Nogami＇s （2006） taxonomy of the speech act of complaint to examine the main components of complaint, the level of directness and the degree of mitigation. It is anticipated that the findings will be able to provide valuable insights into teaching and learning English in non-native settings.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10275048 and 10175008, and the Natural Science Foundation of Zhejiang Province of China under Grant No. 102067
文摘We propose an aggregation model of a two-species system to mimic the growth of cities＇ population and assets, in which irreversible coagulation reactions and exchange reactions occur between any two aggregates of the same species, and the monomer-birth reactions of one species occur by the catalysis Of the other species. In the case with population-catalyzed birth of assets, the rate kernel of an asset aggregate Bκ of size k grows to become an aggregate Bκ＋1 through a monomer-birth catalyzed by a population aggregate Aj of size j is J（κ,j） = Jkjλ. And in mutually catalyzed birth model, the birth rate kernels of population and assets are H（k,j）=Hkjη and J（k,j） = Jkjλ, respectively. The kinetics of the system is investigated based on the mean-field theory. In the model of population-catalyzed birth of aseets, the long-time asymptotic behavior of the assets aggregate size distribution obeys the conventional or modified scaling form. In mutually catalyzed birth system, the asymptotic behaviors of population and assets obey the conventional scaling form in the case of η=λ =0, and they obey the modified scaling form in the case of η=0, λ=1. In the case of η = λ= 1, the total mass of population aggregates and that of asset aggregates both grow much faster than those in population-catalyzed birth of assets model, and they approaches to infinite values in finite time.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10772133 and 11072172)the Doctoral Fund of Ministry of Education of China (Grant No. 20090032110006)
文摘Extended digital image correlation(X-DIC) method is one novel test method in experimental mechanics.In this paper,the principle of the X-DIC method was introduced in detail.A selection scheme of the initial value of Newton iteration method was proposed when Newton iteration method was applied to solve the partial differential equations.This scheme could make the X-DIC method suitable for the large deformation measurement and avoid the non-convergence phenomenon effectively.The performance of the X-DIC method was verified by simulated images.Since the pixel point with the maximum absolute error occurred mainly at the corner or on the interface of the region of interest(ROI,region used for correlation calculation),measured deformation of the core area(area surrounding the center point of the ROI with a smaller size) was taken as the reliable measured value.The measurement accuracy of the X-DIC method could be improved greatly by using the core area.Combined with a long-distance microscope,the X-DIC method could be used in the deformation measurement of the micro-region.Zero deformation experiment was done to test the precision of the measurement system.Then,the X-DIC method was applied to measure the micro-region deformation of the specimen with a crack.Test value was proved to be in accordance with the actual deformation,showing that the X-DIC method is suitable for the research of microscale mechanical behavior of materials.
文摘In recent years, there has been a growing interest toward Blast Furnace Gas （BFG） as a low-grade energy source for industrial furnaces. This paper considers the revamping of a galvanic plant furnace converted to BFG from natural gas. In the design of the new system, the ejector on the exhaust line is a critical component. This paper studies the flow behavior of the ejector using a Computational Fluid Dynamics （CFD） analysis. The CFD model is based on a 3D representation of the ejector, using air and exhaust gases as working fluids. This paper is divided in three parts. In the first part, the galvanic plant used as case study is presented and discussed, in the second part the CFD approach is outlined, and in the third part the CFD approach is validated using experimental data and the numerical results are presented and discussed. Different Reynolds-Averaged Navier-Stokes （RANS） turbulence models （k-to SST and k-e Realizable） are evaluated in terms of convergence capability and accuracy in predicting the pressure drop along the ejector. Suggestions for future optimization of the system are also provided.
