Nature is amazing!Sometimes you don’t need a weather App to predict rain or shine-you just need nature!Feel the heat:listen to crickets Want to know the outside temperature?Listen to the crickets!Count how many times...Nature is amazing!Sometimes you don’t need a weather App to predict rain or shine-you just need nature!Feel the heat:listen to crickets Want to know the outside temperature?Listen to the crickets!Count how many times a cricket chirps in 15 seconds and add 40.That’s the temperature in Fahrenheit(华氏温度,1℉≈0.56℃).Do it several times and find the average.展开更多
In pre-modern China,systematic records of astronomical phenomena measured by units including“zhang,”“chi,”and“cun”and records using phrases such as“as large as something”(making comparison with images取象比类)...In pre-modern China,systematic records of astronomical phenomena measured by units including“zhang,”“chi,”and“cun”and records using phrases such as“as large as something”(making comparison with images取象比类)were kept.Some of these records survive and together they constitute a“scale system”for records of astronomical phenomena.A textual model of the celestial sphere based on naked eye observations also survives.According to this model and using the conversion ratio that 1 chi equals 1 degree,the author has reconstituted the geometric meaning of the records of“zhang,”“chi,”and“cun,”while records that use a comparison with a certain object have been converted to their apparent diameters or magnitudes.Finally,these two records are integrated into one system.Through an analysis of the origin of the chi system,the author obtains the result that the radius of the celestial sphere when the ancients observed the sky with the naked eye was about 13 meters.The paper supports this conclusion from various perspectives,including psychological factors,the radius of planetariums,and the nautical Method of Reckoning by the Stars.As naked eye observers always regard the vault of heaven as a plane hemisphere,they have a common false impression in their minds;the pre-modern observational data therefore contains some systematic errors.Under different illumination and weather conditions,the vault of heaven is plane in varying degrees,for which the author has defined“the angle of apparent plane degree”视扁度角.To correct the visual errors,the author has devised a series of calculation tables for daytime,nighttime,cloudy days,clear days,moonlit nights,and moonless nights,to convert the apparent heights or sizes of celestial bodies to the true heights or sizes.展开更多
This thesis sets out to classify the fossilized errors made by the subjects from lexical and syntactic levels respectively,through the empirical experiment and questionnaire.
This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization usin...This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.展开更多
文摘Nature is amazing!Sometimes you don’t need a weather App to predict rain or shine-you just need nature!Feel the heat:listen to crickets Want to know the outside temperature?Listen to the crickets!Count how many times a cricket chirps in 15 seconds and add 40.That’s the temperature in Fahrenheit(华氏温度,1℉≈0.56℃).Do it several times and find the average.
文摘In pre-modern China,systematic records of astronomical phenomena measured by units including“zhang,”“chi,”and“cun”and records using phrases such as“as large as something”(making comparison with images取象比类)were kept.Some of these records survive and together they constitute a“scale system”for records of astronomical phenomena.A textual model of the celestial sphere based on naked eye observations also survives.According to this model and using the conversion ratio that 1 chi equals 1 degree,the author has reconstituted the geometric meaning of the records of“zhang,”“chi,”and“cun,”while records that use a comparison with a certain object have been converted to their apparent diameters or magnitudes.Finally,these two records are integrated into one system.Through an analysis of the origin of the chi system,the author obtains the result that the radius of the celestial sphere when the ancients observed the sky with the naked eye was about 13 meters.The paper supports this conclusion from various perspectives,including psychological factors,the radius of planetariums,and the nautical Method of Reckoning by the Stars.As naked eye observers always regard the vault of heaven as a plane hemisphere,they have a common false impression in their minds;the pre-modern observational data therefore contains some systematic errors.Under different illumination and weather conditions,the vault of heaven is plane in varying degrees,for which the author has defined“the angle of apparent plane degree”视扁度角.To correct the visual errors,the author has devised a series of calculation tables for daytime,nighttime,cloudy days,clear days,moonlit nights,and moonless nights,to convert the apparent heights or sizes of celestial bodies to the true heights or sizes.
文摘This thesis sets out to classify the fossilized errors made by the subjects from lexical and syntactic levels respectively,through the empirical experiment and questionnaire.
基金supports for this project from the National Natural Science Foundation of China(22378295).
文摘This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.
