The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and tempora...The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative correlation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), composite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and composite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the competitive relationship between compaction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass.展开更多
Previous studies show that infrared radiation temperature(IRT)abnormalities are always accompanied by the crack development in rocks under external loads.In this context,experiments were conducted on preflawed sandsto...Previous studies show that infrared radiation temperature(IRT)abnormalities are always accompanied by the crack development in rocks under external loads.In this context,experiments were conducted on preflawed sandstone to investigate the infrared radiation characteristics during failure process.Two indicators were defined herein,i.e.coefficient of variation of IRT(CVIRT)and skewness of IRT(SIRT).The regression analysis shows that the IRT probability distributions during loading process fit the Gaussian model.The variations in the CVIRT are characterized by four stages:primary stage,steady stage,accelerating stage and post-peak stage.Besides,the variations in the SIRT are divided into three stages:primary stage,steady stage and failure and post-peak stage.The precursor point for preflawed rock failure is identified based on the CVIRTetime curve,with average precursor point of 83%of the peak stress.Compared with other IRT indicators,the proposed two IRT indicators have higher sensitivity to IRT abnormalities during failure process.Furthermore,the connection between the IRT indicators and the rock fracturing was investigated to interpret the IRT indicator abnormalities.Based on the Verhulst inverse function,a new quantitative model was presented to describe the primary stage,steady stage and accelerating stage of the CVIRTetime curve.The results obtained in this study can provide early-warning information for rock failure prediction.展开更多
Hot air(HA)drying of banana has low drying efficiency and results in undesirable product quality.The objectives of this research were to investigate the feasibility of infrared(IR)heating to improve banana drying rate...Hot air(HA)drying of banana has low drying efficiency and results in undesirable product quality.The objectives of this research were to investigate the feasibility of infrared(IR)heating to improve banana drying rate,evaluate quality of the dried product,and establish models for predicting drying characteristics.Banana slices of 5 mm and 8 mm thickness were dried with IR and HA at product temperatures of 60℃,70℃ and 80℃.Banana drying characteristics and changes in residual polyphenol oxidase(PPO),Hydroxymethylfurfural(HMF),color,moisture content(MC)and water activity during the treatments were investigated.Results showed that significant moisture reduction and higher drying rates were achieved with IR drying compared to HA drying in the early stage.The drying data could be fitted to the Page model for accurate prediction of MC change for IR and HA drying with mean R2 of 0.983.It was noted that enzyme inactivation occurred more quickly with IR than with HA drying.A unique response of PPO under IR and HA drying was revealed.IR heating of banana inactivated PPO within the first 20 min of drying at 60℃,70℃ and 80℃,while PPO was first activated before inactivation at 60℃ and 70℃ drying with HA.The highest HMF content occurred in banana slices with 5 mm thickness dried with IR at a product temperature of 80℃.It is therefore recommendable to dry banana with IR at product temperature of 70℃ or below to preserve the product quality.These findings are new and provide more insight in the application of IR heating for drying banana for improved drying rate and product quality.展开更多
A three-dimensional infrared radiation code for exhaust system was developed by the finite volume method coupled with narrow band k-distribution in non-gray absorbing-emitting media.The final infrared signature had co...A three-dimensional infrared radiation code for exhaust system was developed by the finite volume method coupled with narrow band k-distribution in non-gray absorbing-emitting media.The final infrared signature had considered the atmosphere effect,and the simulation values were favorably consistent with testing ones.The results indicate that the relative errors considering the effect of atmosphere compared with that of the contrary condition reduce by 31%,it shows that when simulating the infrared radiation of the target which is received by the infrared detectors,even the calculation band is in atmospheric windows 3～5 μm,the effect of atmospheric transmission on infrared signature of the target should not be neglected.展开更多
To address deeper understandings about the aero-thermal performance of an integrating infrared suppressor under more realistic situations,a numerical investigation is motivated in the current study,concerning the effe...To address deeper understandings about the aero-thermal performance of an integrating infrared suppressor under more realistic situations,a numerical investigation is motivated in the current study,concerning the effects of forward-flight speed on exhaust plume flow and infrared radiation of the Infrared Suppressor-integrating(IRS-integrating)helicopter,wherein the forward-flight speed is changed from 0 m/s(hover state)to 100 m/s,while both the engine exhaust parameters and the main-rotor operation parameters remains unchanged during different forward-flight velocities.The results show that the interaction between forward-flight flow and downwash flow alters the exhaust plume development and the internal flow inside the IRS-integrating rear fuselage more complicatedly,tightly dependent on the forward-flight speed.Of particular concern is the situation where the forward-flight flow has nearly the same level as the downwash flow,the hot mixing flow could possibly interacts with the helicopter rear fuselage to play a local heating effect.With the increase of forward-flight speed,the ejection coefficient is generally increased and the average exhaust temperature of mixing flow is decreased,leading to a reduction of the infrared radiation intensity of exhaust plume in 3–5 lm band.However,the influence of forward-flight speed on the overall infrared radiation intensity of IRS-integrating helicopter is conjectured not monotonous due to the complicated interaction between forward-flight flow and downwash flow.Under high-speed forward-flight states,the overall infrared radiation intensity of the IRS-integrating helicopter in 3–5 lm band is reduced with the increase of forward-flight speed.With respect to 3–5 lm band,the forward-flight speed has little effect on the infrared radiation in 8–14 lm band.展开更多
A coupled model,capable of simulating transonic flow,solid heat conduction,species transport,and gas radiation,is developed that provides better computational treatment of infrared radiation from hot exhaust nozzles.T...A coupled model,capable of simulating transonic flow,solid heat conduction,species transport,and gas radiation,is developed that provides better computational treatment of infrared radiation from hot exhaust nozzles.The modeling of gas radiation is based on a statistical narrow-band correlated-k analysis,whose parameters are deduced from the HITEMP line-by-line database.To improve computational efficiency,several methods are employed.A mixed analytical-numerical algorithm is described for the stiffness of the two-equation turbulence model and an alternating direction implicit pretreatment for the ill-conditioned matrix appearing in the coupled problem of flow and solid heat conduction.Moreover,an improved multigrid method and a symmetry plane treatment of the radiation transfer-energy equations are also introduced.Four numerical simulations are given to confirm the efficiency and accuracy of the numerical method.Finally,an account of the aerothermodynamics and infrared characteristics for two types of nozzles are presented.The infrared radiation intensity of the Chevron ejecting nozzle is clearly smaller than that of the common axisymmetric ejecting nozzle.All computations can be performed on a personal computer.展开更多
Objective:This paper mainly analyzes the effect of infrared radiation combined with external application nursing on maintenance of vascular access in hemodialysis patients.Methods:A total of 150 hemodialysis patients ...Objective:This paper mainly analyzes the effect of infrared radiation combined with external application nursing on maintenance of vascular access in hemodialysis patients.Methods:A total of 150 hemodialysis patients in our hospital from December 2019 to September 2020 were divided into the conventional group and the study group,75 cases in each group.The conventional group was given external application nursing alone,and the study group was given infrared radiation combined with external application nursing,and the effect on the maintenance of vascular access was counted.Results:After the intervention,the indexes of URR,kt/V and human albumin in the study group were higher than those in the routine group,and the indexes of β2-mg and MIS in the study group were lower than those in the routine group,P<0.05;The improvement of vascular elasticity and quality of life in the study group was higher than that in the conventional group,and the incidence of complications was lower than that in the conventional group,P<0.05.Conclusion:Infrared radiation combined with external application of nursing care in hemodialysis patients with vascular access maintenance effect is significant,can effectively improve vascular elasticity.展开更多
Hypersonic vehicles emit strong infrared radiation from their high-temperature exhaust plume and body, which is critical for infrared early warning, tracking, and guidance. In this work, a comprehensive analysis is co...Hypersonic vehicles emit strong infrared radiation from their high-temperature exhaust plume and body, which is critical for infrared early warning, tracking, and guidance. In this work, a comprehensive analysis is conducted on the factors involved in air dissociation reaction within the shock layer of hypersonic missile heads, as well as the multi-component afterburning effect of the exhaust plume. A novel Reverse Monte Carlo Method(RMCM) is proposed for infrared radiation calculation, which utilizes two-dimensional Low-Discrepancy Sequences(LDS) to improve computational accuracy. The numerical calculations for a dagger-type missile show that afterburning reactions increase the temperature on the centerline of the outlet exhaust plume by about 1000 K. The total infrared radiation intensity of the missile is the highest in the 1–3 μm band, with the hightemperature wall of the nozzle being the primary source of solid radiation, and gas radiation primarily coming from H_(2)O. The radiation intensity of the missile exhaust plume in the 3–5 μm band is the highest, with radiation sources primarily coming from CO_(2), CO, and HCl. Afterburning reactions of the exhaust plume increase the total infrared radiation intensity of the missile by about 0.7times. These results can provide reference for the detection and guidance of hypersonic missiles.展开更多
This paper contributes to explain the global warming instead of"giving up"and thinking about passively adapting to climate change or global warming.It makes more sense to tackle what creates the greenhouse e...This paper contributes to explain the global warming instead of"giving up"and thinking about passively adapting to climate change or global warming.It makes more sense to tackle what creates the greenhouse effect and contributes to global warming.The greenhouse effect is not only due to GHGs emissions,but also to the excess IR radiation emitted during the day,by artificial surfaces,following the absorption of solar radiation.The phenomenon should be compared to that of radiative forcing well known by climatologists and which makes the link between atmospheric pollution and the density of heat fluxes stopped by the atmosphere inducing global warming.It becomes clear that type an equation here.The surplus CO2 and IR radiation emissions influence global warming,not to mention the direct part of the heat released by the combustion of fossil fuels and even renewable(wood fires,biogas,friction of wind turbine propellers with the air).展开更多
Chalkboard erasers that are commonly used in many schools and education organizations have <span>the </span><span>poor ability in removing the dust off the chalkboard and collect them. The dust that ...Chalkboard erasers that are commonly used in many schools and education organizations have <span>the </span><span>poor ability in removing the dust off the chalkboard and collect them. The dust that is not collected will be taken into human bodies via inhalation, which will lead to respiratory diseases. Therefore, it is crucial to design a chalkboard eraser that can collect the dust effectively. If the eraser can be controlled both remotely and manually by people, it can further reduce the amount of dust taken in by human bodies. To achieve remote control, a micro-controller is needed to transfer the infrared radiation (IR) into signals that can control electric motors to move around on the chalkboard. Furthermore, the microfiber is also used as the cleaning material to improve the performance of dust cleaning and collecting. A vacuum pump is needed to create negative pressure between the eraser and the chalkboard so that the eraser can stick to it. The result shows a stronger ability in removing and collecting dust. With the help of the Arduino UNO board, the remote control is successfully achieved, and the eraser can move on the chalkboard freely according to the order.</span>展开更多
Atmospheric radiative fluxes are evaluated for the line-by-line model of spectral lines in considering the atmosphere as a weakly nonuniform plane layer and altitude profiles of its parameters are taken from the model...Atmospheric radiative fluxes are evaluated for the line-by-line model of spectral lines in considering the atmosphere as a weakly nonuniform plane layer and altitude profiles of its parameters are taken from the model of standard atmosphere.Concepts of molecular spectroscopy are combined with the local thermodynamic equilibrium for greenhouse gases and with information from HITRAN data base for parameters of radiative transitions.In addition,the energetic balance of the Earth allows one to determine the radiative flux from clouds.As a result,the algorithm is worked out for evaluation of the atmospheric radiative flux toward the Earth depending on its composition.We below concentrate on the change of atmospheric radiative fluxes as a result of doubling of the concentration of CO2 molecules.It is shown that the change of the global temperature in this case according to the above algorithm in 5-6 times exceeds that followed from climatological models which are based on old spectral data,rather than those from HITRAN data base.These codes ignore overlapping of spectral lines of atmospheric radiators.展开更多
Semitransparent organic solar cells(ST-OSCs)have the potentials to open promising applications that differ from those of conventional inorganic ones,such as see-through power windows with both energy generation and he...Semitransparent organic solar cells(ST-OSCs)have the potentials to open promising applications that differ from those of conventional inorganic ones,such as see-through power windows with both energy generation and heat insulation functions.However,to achieve so,there remain significant challenges,especially for balancing critical parameters,such as power conversion efficiency(PCE),average visible transparency(AVT)and low energy infrared photon radiation rejection(IRR)to realize the full potentials of ST-OSCs.Herein,we demonstrate the new design of ST-OSCs through the rational integration of organic materials,transparent electrode and infrared photon reflector in one device.With the assistance of optical simulation,new ST-OSCs with precise layout exhibit state-of-art performance,with near 30%AVT and PCE of 7.3%,as well as an excellent IRR of over 93%(780-2500 nm),representing one of best multifunctional ST-OSCs with promising perspective for window application.展开更多
Electrothermal metasurfaces have garneredconsiderable attention owing to their ability to dynamicallycontrol thermal infrared radiation. Although previousstudies were mainly focused on metasurfaces with infiniteunit c...Electrothermal metasurfaces have garneredconsiderable attention owing to their ability to dynamicallycontrol thermal infrared radiation. Although previousstudies were mainly focused on metasurfaces with infiniteunit cells, in practice, the finite-size effect can be a criticaldesign factor for developing thermal metasurfaces withfast response and broad temperature uniformity. Here, westudy the thermal metasurfaces consisting of goldnanorods with a finite array size, which can achieve aresonance close to that of the infinite case with onlyseveral periods. More importantly, such a small footprintdue to the finite array size yields response time down to ananosecond level. Furthermore, the number of the unitcells in the direction perpendicular to the axis of nanorodsis found to be insensitive to the resonance and responsetime;thus, providing a tunable aspect ratio that can boostthe temperature uniformity in the sub-Kelvin level.展开更多
The yield reduction caused by miss-seeding in potato mechanized sowing is astonishing.The existing research always needs to install a spare compensator on the original seed-metering device.Therefore,problems of comple...The yield reduction caused by miss-seeding in potato mechanized sowing is astonishing.The existing research always needs to install a spare compensator on the original seed-metering device.Therefore,problems of complex planter structure and compensated potato seed poor landing accuracy need to be solved urgently.Consequently,a scheme of integrated seeding and compensating potato planter based on one-way clutch is proposed in this paper.Based on a basic‘improved one raw potato planter’and the working principle of one-way clutch,power of seed-metering system is provided through main power transmission one-way clutch by land wheels when the system works properly.However,when miss-seeding detection system with infrared radiation deciding that a miss-seeding incident has happened,the seed-metering power will be replaced by a compensatory motor through compensating one-way clutch at a higher speed.Thus,the idea of catching-up compensation can be realized.After compensation is completed,the system controller disconnects the compensatory motor,and the seed-metering power will naturally switch to the land wheels again.A prototype based on this idea was built.Field tests showed that the accuracy of seed monitoring system is more than 99.9%;the adoption of catching-up compensation scheme does not bring about empty spoon rate rise significantly.Within the range of 0.2-0.8 m/s of the seed-metering chain speed,although the average success compensation rate decreases evidently with the increase of the chain speed,the success compensation rate is still near 70%even at 0.8 m/s,the vast majority of missed seeds can be compensated effectively.展开更多
The development of multifunctional materials and synergistic applications of various functions are important conditions for integrated and miniaturized equipment.Here,we developed asymmetric MXene/aramid nanofibers/po...The development of multifunctional materials and synergistic applications of various functions are important conditions for integrated and miniaturized equipment.Here,we developed asymmetric MXene/aramid nanofibers/polyimides(AMAP)aerogels with different modules using an integrated molding process.Cleverly asymmetric modules(layered MXene/aramid nanofibers section and porous MXene/aramid nanofibers/polyimides section)interactions are beneficial for enhanced performances,resulting in low reflection electromagnetic interference(EMI)shielding(specific shielding effectiveness of 2483(dB·cm^(3))/g and a low R-value of 0.0138),high-efficiency infrared radiation(IR)stealth(ultra-low thermal conductivity of 0.045 W/(m·K)and IR emissivity of 0.32 at 3–5μm and 0.28 at 8–14μm),and excellent thermal management performances of insulated Joule heating.Furthermore,these multifunctional AMAP aerogels are suitable for various application scenarios such as personal and building protection against electromagnetic pollution and cold,as well as military equipment protection against infrared detection and EMI.展开更多
基金National Natural Science Foundation of China(No.52178393)2023 High-level Talent Research Project from Yancheng Institute of Technology(No.xjr2023019)+1 种基金Open Fund Project of Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering(Grant No.YT202302)Science and Technology Innovation Team of Shaanxi Innovation Capability Support Plan(No.2020TD005).
文摘The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative correlation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), composite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and composite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the competitive relationship between compaction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass.
基金The research was funded by the National Natural Science Foundation of China(Grant No.11902128)the Applied Basic Research Foundation of Yunnan Province(Grant Nos.2019FI012 and 2018FB093)。
文摘Previous studies show that infrared radiation temperature(IRT)abnormalities are always accompanied by the crack development in rocks under external loads.In this context,experiments were conducted on preflawed sandstone to investigate the infrared radiation characteristics during failure process.Two indicators were defined herein,i.e.coefficient of variation of IRT(CVIRT)and skewness of IRT(SIRT).The regression analysis shows that the IRT probability distributions during loading process fit the Gaussian model.The variations in the CVIRT are characterized by four stages:primary stage,steady stage,accelerating stage and post-peak stage.Besides,the variations in the SIRT are divided into three stages:primary stage,steady stage and failure and post-peak stage.The precursor point for preflawed rock failure is identified based on the CVIRTetime curve,with average precursor point of 83%of the peak stress.Compared with other IRT indicators,the proposed two IRT indicators have higher sensitivity to IRT abnormalities during failure process.Furthermore,the connection between the IRT indicators and the rock fracturing was investigated to interpret the IRT indicator abnormalities.Based on the Verhulst inverse function,a new quantitative model was presented to describe the primary stage,steady stage and accelerating stage of the CVIRTetime curve.The results obtained in this study can provide early-warning information for rock failure prediction.
文摘Hot air(HA)drying of banana has low drying efficiency and results in undesirable product quality.The objectives of this research were to investigate the feasibility of infrared(IR)heating to improve banana drying rate,evaluate quality of the dried product,and establish models for predicting drying characteristics.Banana slices of 5 mm and 8 mm thickness were dried with IR and HA at product temperatures of 60℃,70℃ and 80℃.Banana drying characteristics and changes in residual polyphenol oxidase(PPO),Hydroxymethylfurfural(HMF),color,moisture content(MC)and water activity during the treatments were investigated.Results showed that significant moisture reduction and higher drying rates were achieved with IR drying compared to HA drying in the early stage.The drying data could be fitted to the Page model for accurate prediction of MC change for IR and HA drying with mean R2 of 0.983.It was noted that enzyme inactivation occurred more quickly with IR than with HA drying.A unique response of PPO under IR and HA drying was revealed.IR heating of banana inactivated PPO within the first 20 min of drying at 60℃,70℃ and 80℃,while PPO was first activated before inactivation at 60℃ and 70℃ drying with HA.The highest HMF content occurred in banana slices with 5 mm thickness dried with IR at a product temperature of 80℃.It is therefore recommendable to dry banana with IR at product temperature of 70℃ or below to preserve the product quality.These findings are new and provide more insight in the application of IR heating for drying banana for improved drying rate and product quality.
文摘A three-dimensional infrared radiation code for exhaust system was developed by the finite volume method coupled with narrow band k-distribution in non-gray absorbing-emitting media.The final infrared signature had considered the atmosphere effect,and the simulation values were favorably consistent with testing ones.The results indicate that the relative errors considering the effect of atmosphere compared with that of the contrary condition reduce by 31%,it shows that when simulating the infrared radiation of the target which is received by the infrared detectors,even the calculation band is in atmospheric windows 3～5 μm,the effect of atmospheric transmission on infrared signature of the target should not be neglected.
基金financial supports for this project from the National Science and Technology Major Project of China(No.J2019-III-0009-0053)。
文摘To address deeper understandings about the aero-thermal performance of an integrating infrared suppressor under more realistic situations,a numerical investigation is motivated in the current study,concerning the effects of forward-flight speed on exhaust plume flow and infrared radiation of the Infrared Suppressor-integrating(IRS-integrating)helicopter,wherein the forward-flight speed is changed from 0 m/s(hover state)to 100 m/s,while both the engine exhaust parameters and the main-rotor operation parameters remains unchanged during different forward-flight velocities.The results show that the interaction between forward-flight flow and downwash flow alters the exhaust plume development and the internal flow inside the IRS-integrating rear fuselage more complicatedly,tightly dependent on the forward-flight speed.Of particular concern is the situation where the forward-flight flow has nearly the same level as the downwash flow,the hot mixing flow could possibly interacts with the helicopter rear fuselage to play a local heating effect.With the increase of forward-flight speed,the ejection coefficient is generally increased and the average exhaust temperature of mixing flow is decreased,leading to a reduction of the infrared radiation intensity of exhaust plume in 3–5 lm band.However,the influence of forward-flight speed on the overall infrared radiation intensity of IRS-integrating helicopter is conjectured not monotonous due to the complicated interaction between forward-flight flow and downwash flow.Under high-speed forward-flight states,the overall infrared radiation intensity of the IRS-integrating helicopter in 3–5 lm band is reduced with the increase of forward-flight speed.With respect to 3–5 lm band,the forward-flight speed has little effect on the infrared radiation in 8–14 lm band.
文摘A coupled model,capable of simulating transonic flow,solid heat conduction,species transport,and gas radiation,is developed that provides better computational treatment of infrared radiation from hot exhaust nozzles.The modeling of gas radiation is based on a statistical narrow-band correlated-k analysis,whose parameters are deduced from the HITEMP line-by-line database.To improve computational efficiency,several methods are employed.A mixed analytical-numerical algorithm is described for the stiffness of the two-equation turbulence model and an alternating direction implicit pretreatment for the ill-conditioned matrix appearing in the coupled problem of flow and solid heat conduction.Moreover,an improved multigrid method and a symmetry plane treatment of the radiation transfer-energy equations are also introduced.Four numerical simulations are given to confirm the efficiency and accuracy of the numerical method.Finally,an account of the aerothermodynamics and infrared characteristics for two types of nozzles are presented.The infrared radiation intensity of the Chevron ejecting nozzle is clearly smaller than that of the common axisymmetric ejecting nozzle.All computations can be performed on a personal computer.
文摘Objective:This paper mainly analyzes the effect of infrared radiation combined with external application nursing on maintenance of vascular access in hemodialysis patients.Methods:A total of 150 hemodialysis patients in our hospital from December 2019 to September 2020 were divided into the conventional group and the study group,75 cases in each group.The conventional group was given external application nursing alone,and the study group was given infrared radiation combined with external application nursing,and the effect on the maintenance of vascular access was counted.Results:After the intervention,the indexes of URR,kt/V and human albumin in the study group were higher than those in the routine group,and the indexes of β2-mg and MIS in the study group were lower than those in the routine group,P<0.05;The improvement of vascular elasticity and quality of life in the study group was higher than that in the conventional group,and the incidence of complications was lower than that in the conventional group,P<0.05.Conclusion:Infrared radiation combined with external application of nursing care in hemodialysis patients with vascular access maintenance effect is significant,can effectively improve vascular elasticity.
基金supported by the National Defense Science and Technology Pre-Research Fund, China (No. KJXYY2019054/M51)。
文摘Hypersonic vehicles emit strong infrared radiation from their high-temperature exhaust plume and body, which is critical for infrared early warning, tracking, and guidance. In this work, a comprehensive analysis is conducted on the factors involved in air dissociation reaction within the shock layer of hypersonic missile heads, as well as the multi-component afterburning effect of the exhaust plume. A novel Reverse Monte Carlo Method(RMCM) is proposed for infrared radiation calculation, which utilizes two-dimensional Low-Discrepancy Sequences(LDS) to improve computational accuracy. The numerical calculations for a dagger-type missile show that afterburning reactions increase the temperature on the centerline of the outlet exhaust plume by about 1000 K. The total infrared radiation intensity of the missile is the highest in the 1–3 μm band, with the hightemperature wall of the nozzle being the primary source of solid radiation, and gas radiation primarily coming from H_(2)O. The radiation intensity of the missile exhaust plume in the 3–5 μm band is the highest, with radiation sources primarily coming from CO_(2), CO, and HCl. Afterburning reactions of the exhaust plume increase the total infrared radiation intensity of the missile by about 0.7times. These results can provide reference for the detection and guidance of hypersonic missiles.
文摘This paper contributes to explain the global warming instead of"giving up"and thinking about passively adapting to climate change or global warming.It makes more sense to tackle what creates the greenhouse effect and contributes to global warming.The greenhouse effect is not only due to GHGs emissions,but also to the excess IR radiation emitted during the day,by artificial surfaces,following the absorption of solar radiation.The phenomenon should be compared to that of radiative forcing well known by climatologists and which makes the link between atmospheric pollution and the density of heat fluxes stopped by the atmosphere inducing global warming.It becomes clear that type an equation here.The surplus CO2 and IR radiation emissions influence global warming,not to mention the direct part of the heat released by the combustion of fossil fuels and even renewable(wood fires,biogas,friction of wind turbine propellers with the air).
文摘Chalkboard erasers that are commonly used in many schools and education organizations have <span>the </span><span>poor ability in removing the dust off the chalkboard and collect them. The dust that is not collected will be taken into human bodies via inhalation, which will lead to respiratory diseases. Therefore, it is crucial to design a chalkboard eraser that can collect the dust effectively. If the eraser can be controlled both remotely and manually by people, it can further reduce the amount of dust taken in by human bodies. To achieve remote control, a micro-controller is needed to transfer the infrared radiation (IR) into signals that can control electric motors to move around on the chalkboard. Furthermore, the microfiber is also used as the cleaning material to improve the performance of dust cleaning and collecting. A vacuum pump is needed to create negative pressure between the eraser and the chalkboard so that the eraser can stick to it. The result shows a stronger ability in removing and collecting dust. With the help of the Arduino UNO board, the remote control is successfully achieved, and the eraser can move on the chalkboard freely according to the order.</span>
文摘Atmospheric radiative fluxes are evaluated for the line-by-line model of spectral lines in considering the atmosphere as a weakly nonuniform plane layer and altitude profiles of its parameters are taken from the model of standard atmosphere.Concepts of molecular spectroscopy are combined with the local thermodynamic equilibrium for greenhouse gases and with information from HITRAN data base for parameters of radiative transitions.In addition,the energetic balance of the Earth allows one to determine the radiative flux from clouds.As a result,the algorithm is worked out for evaluation of the atmospheric radiative flux toward the Earth depending on its composition.We below concentrate on the change of atmospheric radiative fluxes as a result of doubling of the concentration of CO2 molecules.It is shown that the change of the global temperature in this case according to the above algorithm in 5-6 times exceeds that followed from climatological models which are based on old spectral data,rather than those from HITRAN data base.These codes ignore overlapping of spectral lines of atmospheric radiators.
基金funded by Ministry of Science and Technology(No.2017YFA0206600)National Natural Science Foundation of China(Nos.21722404,21674093,21734008,21761132001 and 91633301)+2 种基金International Science and Technology Cooperation Program of China(ISTCP,No.2016YFE0102900)supported by the Fundamental Research Funds for the Central Universities(No.2018XZZX002-16)support by Zhejiang Natural Science Fund for Distinguished Young Scholars(No.LR17E030001)。
文摘Semitransparent organic solar cells(ST-OSCs)have the potentials to open promising applications that differ from those of conventional inorganic ones,such as see-through power windows with both energy generation and heat insulation functions.However,to achieve so,there remain significant challenges,especially for balancing critical parameters,such as power conversion efficiency(PCE),average visible transparency(AVT)and low energy infrared photon radiation rejection(IRR)to realize the full potentials of ST-OSCs.Herein,we demonstrate the new design of ST-OSCs through the rational integration of organic materials,transparent electrode and infrared photon reflector in one device.With the assistance of optical simulation,new ST-OSCs with precise layout exhibit state-of-art performance,with near 30%AVT and PCE of 7.3%,as well as an excellent IRR of over 93%(780-2500 nm),representing one of best multifunctional ST-OSCs with promising perspective for window application.
文摘Electrothermal metasurfaces have garneredconsiderable attention owing to their ability to dynamicallycontrol thermal infrared radiation. Although previousstudies were mainly focused on metasurfaces with infiniteunit cells, in practice, the finite-size effect can be a criticaldesign factor for developing thermal metasurfaces withfast response and broad temperature uniformity. Here, westudy the thermal metasurfaces consisting of goldnanorods with a finite array size, which can achieve aresonance close to that of the infinite case with onlyseveral periods. More importantly, such a small footprintdue to the finite array size yields response time down to ananosecond level. Furthermore, the number of the unitcells in the direction perpendicular to the axis of nanorodsis found to be insensitive to the resonance and responsetime;thus, providing a tunable aspect ratio that can boostthe temperature uniformity in the sub-Kelvin level.
基金We are grateful for the National Natural Science Foundation of China(51765004)the support of Science and Technology Innovation Fund of Gansu Agricultural University(GAU-QDFC-2019-10)+1 种基金the Fuxi Talent Project of Gansu Agricultural University(GAUFX-02J01)and the Sheng Tong Sheng Science and Technology Innovation Fund of Gansu Agricultural University(GSAU-STS-1731).
文摘The yield reduction caused by miss-seeding in potato mechanized sowing is astonishing.The existing research always needs to install a spare compensator on the original seed-metering device.Therefore,problems of complex planter structure and compensated potato seed poor landing accuracy need to be solved urgently.Consequently,a scheme of integrated seeding and compensating potato planter based on one-way clutch is proposed in this paper.Based on a basic‘improved one raw potato planter’and the working principle of one-way clutch,power of seed-metering system is provided through main power transmission one-way clutch by land wheels when the system works properly.However,when miss-seeding detection system with infrared radiation deciding that a miss-seeding incident has happened,the seed-metering power will be replaced by a compensatory motor through compensating one-way clutch at a higher speed.Thus,the idea of catching-up compensation can be realized.After compensation is completed,the system controller disconnects the compensatory motor,and the seed-metering power will naturally switch to the land wheels again.A prototype based on this idea was built.Field tests showed that the accuracy of seed monitoring system is more than 99.9%;the adoption of catching-up compensation scheme does not bring about empty spoon rate rise significantly.Within the range of 0.2-0.8 m/s of the seed-metering chain speed,although the average success compensation rate decreases evidently with the increase of the chain speed,the success compensation rate is still near 70%even at 0.8 m/s,the vast majority of missed seeds can be compensated effectively.
基金supported by the National Key R&D Program of China(No.2021YFB3502500)the National Natural Science Foundation of China(Nos.52172091 and 52172295)+1 种基金Open Fund of Key Laboratory of Materials Preparation and Protection for Harsh Environment(Nanjing University of Aeronautics and Astronautics)Ministry of Industry and Information Technology(No.56XCA22042).
文摘The development of multifunctional materials and synergistic applications of various functions are important conditions for integrated and miniaturized equipment.Here,we developed asymmetric MXene/aramid nanofibers/polyimides(AMAP)aerogels with different modules using an integrated molding process.Cleverly asymmetric modules(layered MXene/aramid nanofibers section and porous MXene/aramid nanofibers/polyimides section)interactions are beneficial for enhanced performances,resulting in low reflection electromagnetic interference(EMI)shielding(specific shielding effectiveness of 2483(dB·cm^(3))/g and a low R-value of 0.0138),high-efficiency infrared radiation(IR)stealth(ultra-low thermal conductivity of 0.045 W/(m·K)and IR emissivity of 0.32 at 3–5μm and 0.28 at 8–14μm),and excellent thermal management performances of insulated Joule heating.Furthermore,these multifunctional AMAP aerogels are suitable for various application scenarios such as personal and building protection against electromagnetic pollution and cold,as well as military equipment protection against infrared detection and EMI.
