The evaporator is the main part of a quick-freeze equipment. There are many factors influencing the heat transfer coefficient of an evaporator. The most important factors among them are the fin shape, tube diameter, d...The evaporator is the main part of a quick-freeze equipment. There are many factors influencing the heat transfer coefficient of an evaporator. The most important factors among them are the fin shape, tube diameter, distance of fin space, frost, and velocity of air flow etc. They mainly influence the thermal efficiency of an evaporator, and therefore its thermal efficiency has direct relationship with the whole efficiency of the quick freeze plant. Evaporators with different structural types have different heat transfer efficiency, in order to obtain high efficiency structure of evaporator, 8 evaporator models with different fin shape, tube diameter and tube arrangement are analyzed and compared. The calculation results show that the integral waved fins, equilateral-triangle arranged small diameter tubes and varying fin-spacing has the highest heat transfer coefficient. The experimental result also shows that the evaporator with this type of structure has better thermal efficiency. The experimental result is in good agreement with the calculation result, it can instruct engineering design for usual designer. A real quick-freeze equipment is designed and put into production. The result shows that, compared with traditional domestic quick-freeze equipments, this equipment decreases by 40% in size and by 20% in energy consumption.展开更多
Information transfer technique is exploitable in teaching EFL Learners English pronunciation. This paper explores its possible application in a remedial lesson for the normal university learners of English major.
A new method to obtain numerical solution of Acoustic Transfer Function (ATF) by BEM is presented. For a simply supported panel backed by a rectangular cavity at low frequency band (0-200 Hz), the frequency property o...A new method to obtain numerical solution of Acoustic Transfer Function (ATF) by BEM is presented. For a simply supported panel backed by a rectangular cavity at low frequency band (0-200 Hz), the frequency property of ATF is analyzed. The relation between the accuracy of the rapid evaluation of sound field and the discretization schemes of the vibrational panel is discussed. The result shows that the method to obtain ATF and the rapid evaluation of sound field using the ATF is suitable to low frequency band. If an appropriate discretization scheme is choosed based on the frequency involved and the effort to obtain ATF, the accuracy of the rapid evaluation of sound field is acceptable.展开更多
The reciprocity measurement theory in anomalous reverberant sound fields was investigated.An improved method Was proposed due to the interrelated errors.The source volume velocity Was corrected by spatial average of m...The reciprocity measurement theory in anomalous reverberant sound fields was investigated.An improved method Was proposed due to the interrelated errors.The source volume velocity Was corrected by spatial average of measurement results and evaluation of the reverberant sound field influence on acoustic energy density.The result was validated in underwater experiment,corrected reciprocity measurement results were almost the same as direct measurement results.It indicates that reverberant sound field does not affect the validitv of the principle,but influences the obtainment of source volume velocity,then influences the measurement of transfer functions with the principle.The proposed method is simple and effective in anomalous reverberant sound fields.The study mav be valuable for the applications which are based on the principle.展开更多
Plate-pin heat sinks are widely used for the electronic cooling system,internal combustion IC engine,cooling of gas turbine blades and other different applications to enhance the thermal performance of heat sinks due ...Plate-pin heat sinks are widely used for the electronic cooling system,internal combustion IC engine,cooling of gas turbine blades and other different applications to enhance the thermal performance of heat sinks due to simplicity,low cost,and a reliable manufacturing process.However,compact heat sinks give higher pressure drop compared with other types of heat sinks.The purpose of this article is to summarise the main advantages and disadvantages of the compact heat sink with some recommendation studies for future works heat sink thermal airflow experiment and simulations.Furthermore,the research attempts to highlight the importance of balance the relationship between the hydraulic performance and the thermal performance of compact heat sinks。展开更多
Medicinal plants are popular and widely used as a major source of herbal drugs and pharmaceutical compounds. Ever-growing demands make medicinal plants faced to several problems including efficacy and safety to meet b...Medicinal plants are popular and widely used as a major source of herbal drugs and pharmaceutical compounds. Ever-growing demands make medicinal plants faced to several problems including efficacy and safety to meet business requirements, conservation, and artificially assisted breeding. As a powerful molecular tool, microsatellites offer the great potentials for various purposes in plants. This review provides a scenario of microsatellites in medicinal plants including development from genomic or expressed sequence tag libraries, cross-species transferability, genotyping, and potential applications. We emphasized on the authentication of medicinal plants by microsatellite markers.展开更多
基金This project is supported by National Key Technologies R&D Programme,China (No.2001BA501A22).
文摘The evaporator is the main part of a quick-freeze equipment. There are many factors influencing the heat transfer coefficient of an evaporator. The most important factors among them are the fin shape, tube diameter, distance of fin space, frost, and velocity of air flow etc. They mainly influence the thermal efficiency of an evaporator, and therefore its thermal efficiency has direct relationship with the whole efficiency of the quick freeze plant. Evaporators with different structural types have different heat transfer efficiency, in order to obtain high efficiency structure of evaporator, 8 evaporator models with different fin shape, tube diameter and tube arrangement are analyzed and compared. The calculation results show that the integral waved fins, equilateral-triangle arranged small diameter tubes and varying fin-spacing has the highest heat transfer coefficient. The experimental result also shows that the evaporator with this type of structure has better thermal efficiency. The experimental result is in good agreement with the calculation result, it can instruct engineering design for usual designer. A real quick-freeze equipment is designed and put into production. The result shows that, compared with traditional domestic quick-freeze equipments, this equipment decreases by 40% in size and by 20% in energy consumption.
文摘Information transfer technique is exploitable in teaching EFL Learners English pronunciation. This paper explores its possible application in a remedial lesson for the normal university learners of English major.
基金This work is supported by the National Natural Science Foundation of China (No.59875069).
文摘A new method to obtain numerical solution of Acoustic Transfer Function (ATF) by BEM is presented. For a simply supported panel backed by a rectangular cavity at low frequency band (0-200 Hz), the frequency property of ATF is analyzed. The relation between the accuracy of the rapid evaluation of sound field and the discretization schemes of the vibrational panel is discussed. The result shows that the method to obtain ATF and the rapid evaluation of sound field using the ATF is suitable to low frequency band. If an appropriate discretization scheme is choosed based on the frequency involved and the effort to obtain ATF, the accuracy of the rapid evaluation of sound field is acceptable.
基金supported by the National Natural Science Foundation of China(51209214)
文摘The reciprocity measurement theory in anomalous reverberant sound fields was investigated.An improved method Was proposed due to the interrelated errors.The source volume velocity Was corrected by spatial average of measurement results and evaluation of the reverberant sound field influence on acoustic energy density.The result was validated in underwater experiment,corrected reciprocity measurement results were almost the same as direct measurement results.It indicates that reverberant sound field does not affect the validitv of the principle,but influences the obtainment of source volume velocity,then influences the measurement of transfer functions with the principle.The proposed method is simple and effective in anomalous reverberant sound fields.The study mav be valuable for the applications which are based on the principle.
文摘Plate-pin heat sinks are widely used for the electronic cooling system,internal combustion IC engine,cooling of gas turbine blades and other different applications to enhance the thermal performance of heat sinks due to simplicity,low cost,and a reliable manufacturing process.However,compact heat sinks give higher pressure drop compared with other types of heat sinks.The purpose of this article is to summarise the main advantages and disadvantages of the compact heat sink with some recommendation studies for future works heat sink thermal airflow experiment and simulations.Furthermore,the research attempts to highlight the importance of balance the relationship between the hydraulic performance and the thermal performance of compact heat sinks。
基金National Natural Science Foundation of China(31270340,31200225,30800624)Instrument Developing Project of the Chinese Academy of Sciences(YZ201227)+1 种基金the Key Research Program of the Chinese Academy of Sciences(Grant NO.KSZD-EW-Z-004)Grant from Zhongning County
文摘Medicinal plants are popular and widely used as a major source of herbal drugs and pharmaceutical compounds. Ever-growing demands make medicinal plants faced to several problems including efficacy and safety to meet business requirements, conservation, and artificially assisted breeding. As a powerful molecular tool, microsatellites offer the great potentials for various purposes in plants. This review provides a scenario of microsatellites in medicinal plants including development from genomic or expressed sequence tag libraries, cross-species transferability, genotyping, and potential applications. We emphasized on the authentication of medicinal plants by microsatellite markers.
