DO we need a fundamental change in our professional culture and knowledge foundation for control and automation?If so,what are necessary and critical steps we must take to ensure such a change would take place effecti...DO we need a fundamental change in our professional culture and knowledge foundation for control and automation?If so,what are necessary and critical steps we must take to ensure such a change would take place effectively and efficiently,or more general,smoothly and sustainably?展开更多
Many family medicine and community health researchers use surveys as an original research methodology.Our purpose is to illustrate how survey research provides an important form of quantitative research that can be ef...Many family medicine and community health researchers use surveys as an original research methodology.Our purpose is to illustrate how survey research provides an important form of quantitative research that can be effectively combined with qualitative data to form a mixed methods study.We first provide an overview of the key principles in survey research and in mixed methods research.We review the various ways that survey can be used in mixed methods studies,citing options such as beginning a study with a survey,using a survey as the second form of data collection,or combining a survey and a form of qualitative data in a single data collection procedure.Finally,we illustrate in a specific example six steps in conducting a mixed methods study using survey research.In a mixed methods study using a survey,primary care researchers should consider six steps.Step 1.Articulate the rationale for mixed methods study.Step 2.Detail quantitative and qualitative databases.Step 3.Identify a mixed methods design.Step 4.Analyse and report the results of the quantitative and qualitative databases.Step 5.Present and show integration.Step 6.Explicate the value of using mixed methods.The ability to combine and integrate survey research into a mixed methods study provides a more rigorous approach to research than conducting only a survey or conducting just a qualitative interview.While requiring skills beyond traditional survey approaches,surveys in primary care offers an opportunity for a high level of sophistication in research methodology.展开更多
The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is ...The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.展开更多
Let K be a basic field of characteristic 0, and fi,i=1,…,r, be polynomials in K(x1,…Xn)Consider the system of algebraic equations which defines an algebraic variety V consisting of zeros of the system in an arbitrar...Let K be a basic field of characteristic 0, and fi,i=1,…,r, be polynomials in K(x1,…Xn)Consider the system of algebraic equations which defines an algebraic variety V consisting of zeros of the system in an arbitrary extension field of K. The study of the structure of V or that of the set展开更多
基金partially supported by the Science and Technology Development Fund of Macao SAR(0050/2020/A1)。
文摘DO we need a fundamental change in our professional culture and knowledge foundation for control and automation?If so,what are necessary and critical steps we must take to ensure such a change would take place effectively and efficiently,or more general,smoothly and sustainably?
文摘Many family medicine and community health researchers use surveys as an original research methodology.Our purpose is to illustrate how survey research provides an important form of quantitative research that can be effectively combined with qualitative data to form a mixed methods study.We first provide an overview of the key principles in survey research and in mixed methods research.We review the various ways that survey can be used in mixed methods studies,citing options such as beginning a study with a survey,using a survey as the second form of data collection,or combining a survey and a form of qualitative data in a single data collection procedure.Finally,we illustrate in a specific example six steps in conducting a mixed methods study using survey research.In a mixed methods study using a survey,primary care researchers should consider six steps.Step 1.Articulate the rationale for mixed methods study.Step 2.Detail quantitative and qualitative databases.Step 3.Identify a mixed methods design.Step 4.Analyse and report the results of the quantitative and qualitative databases.Step 5.Present and show integration.Step 6.Explicate the value of using mixed methods.The ability to combine and integrate survey research into a mixed methods study provides a more rigorous approach to research than conducting only a survey or conducting just a qualitative interview.While requiring skills beyond traditional survey approaches,surveys in primary care offers an opportunity for a high level of sophistication in research methodology.
基金supported by the National Hi-Tech R&D Program of China (No. 2012AA063202)National Key Project of Scientific and Technical Support Program of China (Nos. 2011BAE13B07, 2012BAC02B01, and 2011BAC10B02)National Natural Science Foundation of China (Nos. 51174247 and 50972013)
文摘The effects of the acid leaching and alkali fusion on the leaching efficiency of Y,Eu,Ce,and Tb from the waste rare earth fluorescent powders were investigated in this paper.The results show that hydrochloric acid is better than sulfuric acid in the first acid leaching,and NaOH is better than Na2CO3in the alkali fusion.In the first acid leaching,the Wloss is 20.94%when the waste rare earth fluorescent powders are acid leached in H?concentration 3 mol L-1and S/L ratio 1:3 for 4 h due to red powders dissolved.The better results of the alkali fusion can be got at 800℃ for 2 h when the NaOH is used.The blue powders and the green powders can be dissolved into NaAlO2and oxides such as rare earth oxide(REO).The REO can be dissolved in H?concentration 5 mol L-1,S/L1:10 for 3 h in the second acid leaching.The leaching rates of the Y,Eu,Ce,and Tb are 99.06%,97.38%,98.22%,and 98.15%,respectively.The leaching rate of the total rare earth is 98.60%.
文摘Let K be a basic field of characteristic 0, and fi,i=1,…,r, be polynomials in K(x1,…Xn)Consider the system of algebraic equations which defines an algebraic variety V consisting of zeros of the system in an arbitrary extension field of K. The study of the structure of V or that of the set
