AIM： To choose appropriate concentration of sodium hydroxide（Na OH） solution to establish a stable and consistent corneal alkali burn mouse model in grade II.·METHODS： The mice（n =60） were randomly divided ...AIM： To choose appropriate concentration of sodium hydroxide（Na OH） solution to establish a stable and consistent corneal alkali burn mouse model in grade II.·METHODS： The mice（n =60） were randomly divided into four groups and 15 mice each group. Corneal alkali burns were induced by placing circle filter paper soaked with Na OH solutions on the right central cornea for 30 s.The concentrations of Na OH solutions of groups A, B, C,and D were 0.1 mol/L, 0.15 mol/L, 0.2 mol/L, and 1.0 mol/L respectively. Then these corneas were irrigated with 20 m L physiological saline（0.9% Na Cl）. On day 7 postburn, slit lamp microscope was used to observe corneal opacity,corneal epithelial sodium fluorescein staining positive rate, incidence of corneal ulcer and corneal neovascularization, meanwhile pictures of the anterior eyes were taken. Cirrus spectral domain optical coherence tomography was used to scan cornea to observe corneal epithelial defect and corneal ulcer.·RESULTS： Corneal opacity scores（ x ±s） were not significantly different between the group A and group B（P =0.097）. Incidence of corneal ulcer in group B was significantly higher than that in group A（P =0.035）.Incidence of corneal ulcer and perforation rate in group B was lower than that in group C. Groups C and D had corneal neovascularization, and incidence of corneal neovascularization in group D was significantly higher than that in group C（P =0.000）.·CONCLUSION： Using 0.15 mol/L Na OH can establish grade II mouse model of corneal alkali burns.展开更多
A 30 mm electrothermal-chemical(ETC) gun experimental system is employed to research the burning rate characteristics of 4/7 high-nitrogen solid propellant. Enhanced gas generation rates(EGGR) of propellants during an...A 30 mm electrothermal-chemical(ETC) gun experimental system is employed to research the burning rate characteristics of 4/7 high-nitrogen solid propellant. Enhanced gas generation rates(EGGR) of propellants during and after electrical discharges are verified in the experiments. A modified 0D internal ballistic model is established to simulate the ETC launch. According to the measured pressure and electrical parameters, a transient burning rate law including the influence of EGGR coefficient by electric power and pressure gradient(dp/dt) is added into the model. The EGGR coefficient of 4/7 high-nitrogen solid propellant is equal to 0.005 MW-1. Both simulated breech pressure and projectile muzzle velocity accord with the experimental results well. Compared with Woodley's modified burning rate law, the breech pressure curves acquired by the transient burning rate law are more consistent with test results. Based on the parameters calculated in the model, the relationship among propellant burning rate, pressure gradient(dp/dt) and electric power is analyzed. Depending on the transient burning rate law and experimental data, the burning of solid propellant under the condition of plasma is described more accurately.展开更多
A zero-dimensional single-zone double-curve model is presented to predict fuel burning rate in stratified charge engines, and it is integrated with GT-Power to predict the overall performance of the stratified charge ...A zero-dimensional single-zone double-curve model is presented to predict fuel burning rate in stratified charge engines, and it is integrated with GT-Power to predict the overall performance of the stratified charge engines. The model consists of two exponential functions for calculating the fuel burning rate in different charge zones. The model factors are determined by a non-linear curve fitting technique, based on the experimental data obtained from 30 cases in middle and low loads. The results show good agreement between the measured and calculated cylinder pressures, and the deviation between calculated and measured cylinder pressures is less than 5%. The zerodimensional single-zone double-curve model is successful in the combustion modeling for stratified charge engines.展开更多
Three-dimensional models, consisting of the flame kernel formation model, flame kernel development model and natural gas single step reaction model, are used to analyze the contribution of cyclic equivalence ratio var...Three-dimensional models, consisting of the flame kernel formation model, flame kernel development model and natural gas single step reaction model, are used to analyze the contribution of cyclic equivalence ratio variations to cyclic variations in the compressed natural gas （CNG） lean burn spark ignition engine. Computational results including the contributions of equivalence ratio cyclic variations to each combustion stage and effects of engine speed to the extent of combustion variations are discussed. It is concluded that the equivalence ratio variations affect mostly the main stage of combustion and hardly influence initial kernel development stage.展开更多
目的:探究基于行为分阶段转变理论的护理干预在四肢大面积烧伤后瘢痕整形患者中的应用效果。方法:选取2019年5月-2022年5月于笔者医院行瘢痕整形修复的四肢大面积烧伤后瘢痕患者作为研究对象,根据基于行为分阶段转变理论护理干预在笔者...目的:探究基于行为分阶段转变理论的护理干预在四肢大面积烧伤后瘢痕整形患者中的应用效果。方法:选取2019年5月-2022年5月于笔者医院行瘢痕整形修复的四肢大面积烧伤后瘢痕患者作为研究对象,根据基于行为分阶段转变理论护理干预在笔者医院实施时间,将2019年5月-2020年12月收治的46例患者纳入对照组,给予常规干预;2021年1月-2022年5月收治的44例患者纳入观察组,给予基于行为分阶段转变理论的护理干预。比较干预前和干预3个月后两组患者恐动症信念[恐动症信念评分量表(Kinesiophobia causes scale,KCS)]、恐惧回避信念[恐惧-回避信念问卷(Fear-avoidance beliefs questionnaire,FABQ)]、健康行为[健康行为能力自评量表(Self-rated abilities for health practices scale,SRAHP)]、创面愈合情况[创面愈合时间、温哥华瘢痕量表(Vancouver scar scale,VSS)、瘢痕美容评估与评级量表(Scar cosmesis assessment and rating,SCAR)]、生活质量[烧伤专用健康量表(Burn specific health scale,BSHS-A)]。结果:干预3个月后,两组KCS、FABQ、VSS、SCAR评分均较干预前降低,且观察组低于对照组(均P<0.05);观察组创面愈合时间短于对照组(P<0.05);两组SRAHP、BSHS-A评分较干预前升高,且观察组高于对照组(均P<0.05)。结论:基于行为分阶段转变理论的护理干预可减弱四肢大面积烧伤后瘢痕整形术患者恐动和恐惧回避信念,促进患者健康行为及创面愈合,提高患者生活质量。展开更多
The starting characteristics of thermodynamic undersea vehicle systems are determined by the geometry, size and combustion area of solid propellants, which directly effect liquid propellant pipeline design. It is nece...The starting characteristics of thermodynamic undersea vehicle systems are determined by the geometry, size and combustion area of solid propellants, which directly effect liquid propellant pipeline design. It is necessary to establish accurate burning models for solid propellants. Based on combustion models using powder rings and two different solid ignition grains, namely star-shaped ignition grains and stuffed ignition grains, a mathematic model of the ignition process of the propulsion system was built. With the help of Matlab, a series of calculations were made to determine the effects of different grains on ignition characteristics. The results show that stuffed ignition grain is best suited to be the ignition grain of a thermodynamic undersea vehicle system.展开更多
This article mainly studies the current status of the operation of the“burning money model”of Internet products,expounds and analyzes the disadvantages of this operating model,studies the practical effects brought b...This article mainly studies the current status of the operation of the“burning money model”of Internet products,expounds and analyzes the disadvantages of this operating model,studies the practical effects brought by the“burning money model”,and explores the development direction of future Internet products.Domestic scholars have done a lot of research on the development of Internet products in the future and have achieved certain results.This article aims to discuss the development model of China’s Internet products,summarize the current“burning money”behavior in the operation process of Internet products,and combine the development situation of China’s Internet in the new era to make suggestions for the future development of Internet products.展开更多
Erosive burning is a common burning phenomenon of the gunpowder with inner holes.The actual combustion law of the gunpowder with inner holes can be changed by erosive burning.Pressure difference between the inner and ...Erosive burning is a common burning phenomenon of the gunpowder with inner holes.The actual combustion law of the gunpowder with inner holes can be changed by erosive burning.Pressure difference between the inner and the outer of hole caused by loading density variation of the propellant charge makes erosive burning occur at inner holes during in-bore burning.The effect of erosive burning on burning speed of the propellant is studied by using the effects of flow rate,heat transfer and erosion of the combustion gas in inner holes on burning rate.The mathematic model of erosive burning of the propellant is established.The effects of the factors such as loading density,inner hole size and grain length on erosive burning and interior ballistic performance are analyzed.The method to improve the bore pressure for small charge mass and small firing range by erosive burning is proposed.展开更多
基金Supported by National Science and Technology Major Project of China(No.2011ZXJ09104-10C)
文摘AIM： To choose appropriate concentration of sodium hydroxide（Na OH） solution to establish a stable and consistent corneal alkali burn mouse model in grade II.·METHODS： The mice（n =60） were randomly divided into four groups and 15 mice each group. Corneal alkali burns were induced by placing circle filter paper soaked with Na OH solutions on the right central cornea for 30 s.The concentrations of Na OH solutions of groups A, B, C,and D were 0.1 mol/L, 0.15 mol/L, 0.2 mol/L, and 1.0 mol/L respectively. Then these corneas were irrigated with 20 m L physiological saline（0.9% Na Cl）. On day 7 postburn, slit lamp microscope was used to observe corneal opacity,corneal epithelial sodium fluorescein staining positive rate, incidence of corneal ulcer and corneal neovascularization, meanwhile pictures of the anterior eyes were taken. Cirrus spectral domain optical coherence tomography was used to scan cornea to observe corneal epithelial defect and corneal ulcer.·RESULTS： Corneal opacity scores（ x ±s） were not significantly different between the group A and group B（P =0.097）. Incidence of corneal ulcer in group B was significantly higher than that in group A（P =0.035）.Incidence of corneal ulcer and perforation rate in group B was lower than that in group C. Groups C and D had corneal neovascularization, and incidence of corneal neovascularization in group D was significantly higher than that in group C（P =0.000）.·CONCLUSION： Using 0.15 mol/L Na OH can establish grade II mouse model of corneal alkali burns.
文摘A 30 mm electrothermal-chemical(ETC) gun experimental system is employed to research the burning rate characteristics of 4/7 high-nitrogen solid propellant. Enhanced gas generation rates(EGGR) of propellants during and after electrical discharges are verified in the experiments. A modified 0D internal ballistic model is established to simulate the ETC launch. According to the measured pressure and electrical parameters, a transient burning rate law including the influence of EGGR coefficient by electric power and pressure gradient(dp/dt) is added into the model. The EGGR coefficient of 4/7 high-nitrogen solid propellant is equal to 0.005 MW-1. Both simulated breech pressure and projectile muzzle velocity accord with the experimental results well. Compared with Woodley's modified burning rate law, the breech pressure curves acquired by the transient burning rate law are more consistent with test results. Based on the parameters calculated in the model, the relationship among propellant burning rate, pressure gradient(dp/dt) and electric power is analyzed. Depending on the transient burning rate law and experimental data, the burning of solid propellant under the condition of plasma is described more accurately.
基金Supported by National Natural Science Foundation of China ( No. 50576064)Youth Foundation of Tianjin University (No. W50201).
文摘A zero-dimensional single-zone double-curve model is presented to predict fuel burning rate in stratified charge engines, and it is integrated with GT-Power to predict the overall performance of the stratified charge engines. The model consists of two exponential functions for calculating the fuel burning rate in different charge zones. The model factors are determined by a non-linear curve fitting technique, based on the experimental data obtained from 30 cases in middle and low loads. The results show good agreement between the measured and calculated cylinder pressures, and the deviation between calculated and measured cylinder pressures is less than 5%. The zerodimensional single-zone double-curve model is successful in the combustion modeling for stratified charge engines.
基金Sponsored by the National Natural Science Foundation of China(50406003)
文摘Three-dimensional models, consisting of the flame kernel formation model, flame kernel development model and natural gas single step reaction model, are used to analyze the contribution of cyclic equivalence ratio variations to cyclic variations in the compressed natural gas （CNG） lean burn spark ignition engine. Computational results including the contributions of equivalence ratio cyclic variations to each combustion stage and effects of engine speed to the extent of combustion variations are discussed. It is concluded that the equivalence ratio variations affect mostly the main stage of combustion and hardly influence initial kernel development stage.
文摘目的:探究基于行为分阶段转变理论的护理干预在四肢大面积烧伤后瘢痕整形患者中的应用效果。方法:选取2019年5月-2022年5月于笔者医院行瘢痕整形修复的四肢大面积烧伤后瘢痕患者作为研究对象,根据基于行为分阶段转变理论护理干预在笔者医院实施时间,将2019年5月-2020年12月收治的46例患者纳入对照组,给予常规干预;2021年1月-2022年5月收治的44例患者纳入观察组,给予基于行为分阶段转变理论的护理干预。比较干预前和干预3个月后两组患者恐动症信念[恐动症信念评分量表(Kinesiophobia causes scale,KCS)]、恐惧回避信念[恐惧-回避信念问卷(Fear-avoidance beliefs questionnaire,FABQ)]、健康行为[健康行为能力自评量表(Self-rated abilities for health practices scale,SRAHP)]、创面愈合情况[创面愈合时间、温哥华瘢痕量表(Vancouver scar scale,VSS)、瘢痕美容评估与评级量表(Scar cosmesis assessment and rating,SCAR)]、生活质量[烧伤专用健康量表(Burn specific health scale,BSHS-A)]。结果:干预3个月后,两组KCS、FABQ、VSS、SCAR评分均较干预前降低,且观察组低于对照组(均P<0.05);观察组创面愈合时间短于对照组(P<0.05);两组SRAHP、BSHS-A评分较干预前升高,且观察组高于对照组(均P<0.05)。结论:基于行为分阶段转变理论的护理干预可减弱四肢大面积烧伤后瘢痕整形术患者恐动和恐惧回避信念,促进患者健康行为及创面愈合,提高患者生活质量。
文摘The starting characteristics of thermodynamic undersea vehicle systems are determined by the geometry, size and combustion area of solid propellants, which directly effect liquid propellant pipeline design. It is necessary to establish accurate burning models for solid propellants. Based on combustion models using powder rings and two different solid ignition grains, namely star-shaped ignition grains and stuffed ignition grains, a mathematic model of the ignition process of the propulsion system was built. With the help of Matlab, a series of calculations were made to determine the effects of different grains on ignition characteristics. The results show that stuffed ignition grain is best suited to be the ignition grain of a thermodynamic undersea vehicle system.
文摘This article mainly studies the current status of the operation of the“burning money model”of Internet products,expounds and analyzes the disadvantages of this operating model,studies the practical effects brought by the“burning money model”,and explores the development direction of future Internet products.Domestic scholars have done a lot of research on the development of Internet products in the future and have achieved certain results.This article aims to discuss the development model of China’s Internet products,summarize the current“burning money”behavior in the operation process of Internet products,and combine the development situation of China’s Internet in the new era to make suggestions for the future development of Internet products.
文摘Erosive burning is a common burning phenomenon of the gunpowder with inner holes.The actual combustion law of the gunpowder with inner holes can be changed by erosive burning.Pressure difference between the inner and the outer of hole caused by loading density variation of the propellant charge makes erosive burning occur at inner holes during in-bore burning.The effect of erosive burning on burning speed of the propellant is studied by using the effects of flow rate,heat transfer and erosion of the combustion gas in inner holes on burning rate.The mathematic model of erosive burning of the propellant is established.The effects of the factors such as loading density,inner hole size and grain length on erosive burning and interior ballistic performance are analyzed.The method to improve the bore pressure for small charge mass and small firing range by erosive burning is proposed.
