Nano particles lanthanum modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO 2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at v...Nano particles lanthanum modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO 2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at various temperature. XRD and SEM show that the prepared films have good crystallization behavior and perovskite structure. The crystallite is about 60 nm. The deposition speed is 3 nm/min. This deposition method can exactly control stoichiometry ratios, doping concentration ratio and thickness of PLT thin films. The best annealing process is to bake at 300 ℃ for 10 min and anneal at 600 ℃ for 1 h.展开更多
Nujiang farmers use the innovative dryland rice cultivation technology developed by a Chinese expert team to grow yields and income.As April ushers in spring,mist clings to the deep valleys of the Nujiang Grand Canyon...Nujiang farmers use the innovative dryland rice cultivation technology developed by a Chinese expert team to grow yields and income.As April ushers in spring,mist clings to the deep valleys of the Nujiang Grand Canyon in Southwest China’s Yunnan Province.High on a mountainside in Ziji Village,Daxingdi Town,Lushui City,Nujiang Lisu Autonomous Prefecture,at an altitude exceeding 1,300 metres,62-year-old Lisu villager Cha Wenxing is planting rice.These demonstration plots,cultivating high-quality upland rice,seem to float amongst the clouds.展开更多
As 1.5 million wildebeest pierce the dawn mist of the East African Rift Valley and the roar of lions merges with the cry of zebras beneath sprawling acacia trees,this land unveils life at its rawest-majestic and achin...As 1.5 million wildebeest pierce the dawn mist of the East African Rift Valley and the roar of lions merges with the cry of zebras beneath sprawling acacia trees,this land unveils life at its rawest-majestic and achingly fragile.展开更多
“It's coming!”Liu Fuhai shouted,lying prone on a rock,one of his eyes pressed against his camera.Beads of sweat could be seen on his forehead.Roaring water in the Yellow River plunged from the cliff,making gigan...“It's coming!”Liu Fuhai shouted,lying prone on a rock,one of his eyes pressed against his camera.Beads of sweat could be seen on his forehead.Roaring water in the Yellow River plunged from the cliff,making gigantic splashes(落水声)which eventually turned into thick mists.Liu,holding his breath,clicked the shutter quickly to capture the grandeur of the Hukou Waterfall,the largest waterfall on the Yellow River.展开更多
To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistat...To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.展开更多
The role of cold nitrogen gas and oil mist on tool wear and surface roughness is investigated in turning the K424 nickel-base super alloy with Sialon and SiC whisker-reinforced alumina ceramic tools. A new cooling sys...The role of cold nitrogen gas and oil mist on tool wear and surface roughness is investigated in turning the K424 nickel-base super alloy with Sialon and SiC whisker-reinforced alumina ceramic tools. A new cooling system is developed and used to lower the temperature of the compressed nitrogen gas. Experiments are performed in three different cooling/lubrication modes, i.e. the dry cutting, the cold nitrogen gas （CNG）, and the cold nitrogen gas and oil mist （CNGOM）. Experimental results show that the depth-of-cut notching severely limits the tool life in all the cooling/lubrication modes. Compared with the dry cutting, the use of CNG and CNGOMcan yield higher wear rate of depth-of-cut notching and worse surface finish.展开更多
Green manufacturing （GM） and high efficiency machining technology are inevitable trends in the field of advanced manufacturing of the 21st century. To ensure green and high-efficiency machining, a new high efficienc...Green manufacturing （GM） and high efficiency machining technology are inevitable trends in the field of advanced manufacturing of the 21st century. To ensure green and high-efficiency machining, a new high efficiency cooling technology-cryogenic pneumatic mist jet impinging cooling （CPMJI） technology is presented. For obtaining the best cooling effect, a little quantity of coolant is carried by high speed cryogenic air （-20 C ） and reaches the machining zone in the form of mist jet to enhance heat transfer. Experimental results indicate that under the conditions of 40 m/s in the jet impinging speed and 10 mm in the jet impinging distance, the critical heat flux（CHF） nearly reaches 6× 10^7 W/m^2, more than six times of the CHF of the grinding burn with a value of （8～10）×10^6 W/m^2.展开更多
To understand better the impact on mist net capture rates of the activity height of birds, light intensity, bird richness and abundance, we compared data from mist nets and point counts at the Jianfengling Forest Area...To understand better the impact on mist net capture rates of the activity height of birds, light intensity, bird richness and abundance, we compared data from mist nets and point counts at the Jianfengling Forest Area, Hainan Island. Mist-nets were operated for a total of 7135 net-hours. A total of 587 individuals of 45 bird species were captured. The total mean capture rate was 8.6 ± 10.4 per 100 net-hours. A total of 4932 individuals of 107 bird species were recorded by visual observation alone and 7616 individuals of 120 species were recorded in a visual and aural combination. The Grey-cheeked Fulvetta (Alcippe morrisonia) was the most abundant species, accounting for 38.7% of total captures, 27.9% of visual observations and 22.2% of visual + aural observations. The capture number was correlated with the number observed. Thirty-one species were more likely to be captured than observed. Canopy species, such as members of the Corvidae and Dicruridae, were seldom captured. For all ground feeding species, the capture number was greater than that of observation. Some cryptic species, such as the Lesser Wren Babbler (Napothera epilepidota), Spotnecked Babbler (Stachyris striolata) and Cuckoo Owl (Glaucidium cuculoides) also had a higher relative capture rate than that of observations. There was a significant relationship between light intensity and the number of birds captured.展开更多
（上接《IS0/TC8与IM0要求的关系及其国际标准-2》[1-2]）ISO16437：2012 船舶与海上技术-救生与防火-船舶油雾探测器（Ships and marine technology-Lifesaving and fire protection--Atmospheric oil mist detectors for
The effects of a fine water mist environment in a semi-confined blast chamber on the chemical and thermodynamic processes following detonation of a 20 g PE4 explosive charge have been investigated.The effects were qua...The effects of a fine water mist environment in a semi-confined blast chamber on the chemical and thermodynamic processes following detonation of a 20 g PE4 explosive charge have been investigated.The effects were quantified by the analysis of pressure profiles recorded where several parameters including arrival time of the shock at the sensors, peak overpressures, specific impulse of the positive phase, period of the negative phase and the specific impulse of the multiple reflections were quantified.The effect of the fine water mist on the arrival time, peak pressures and the specific impulse of the positive phase agrees with previous findings in literature. In this paper, the focus is on the implications of the fine water mist on the negative phase and the impulse of multiple pressure reflections. The period of the negative phase was found to have increased by 40% and with higher negative peak pressure in the mist condition compared to the atmospheric condition. The activities of the multiple pressure reflections were found to have decreased considerably, both in number and in amplitude leading to lower impulses(by about 60%) for the water mist conditions.展开更多
To enhance the explosion suppression effects of water mist, various potassium halide additives were tested in a confined vessel filled with a 10% mixture of methane/air. Air and CO2(0.7 MPa) were used as driver gases....To enhance the explosion suppression effects of water mist, various potassium halide additives were tested in a confined vessel filled with a 10% mixture of methane/air. Air and CO2(0.7 MPa) were used as driver gases. The results revealed that halide additives exhibit considerable suppression effects on explosion overpressure. A30% KI mist decreased the explosion overpressure by 27.46% compared with the suppression by pure water mist under the same conditions. When CO2 is used as the driver gas, it will dissolve in water under high pressure.The synergistic effect of a CO2 solution with an effective additive afforded significant suppression. Under the same conditions, the overpressures suppressed by a mist of 30% KI + 0.7 MPa CO2 solution decreased by 33.53% compared with those suppressed by pure water mist driven by air. The synergistic suppression effect is much better than that of a 0.7 MPa CO2 solution mist or 30% KI mist alone. The multicomponent additives can be considered when suppressing methane/air explosions with pressure-formed water mist.展开更多
Combined effects of obstacles and fine water mist on a methane-air explosion of a semi-closed pipe were investigated experimentally.In this study,the diameter of the water mist,the location,and the number of obstacles...Combined effects of obstacles and fine water mist on a methane-air explosion of a semi-closed pipe were investigated experimentally.In this study,the diameter of the water mist,the location,and the number of obstacles was considered.The results demonstrated that 5 μm water mist present a significant suppression affected while 45 μm shows a slight promotion effected on a gas explosion of the condition without obstacles.In the presence of an obstacle,however,the inhibitory effect of 5 μm water veils of mist dropped significantly during flame propagation,and the effect of 45 μm water veils of mist changed from the enhancement of inhibition,and its inhibitory effect was significant.The inhibitory effect of 45 μm water veils of mist on gas explosion weakened firstly and then enhanced with the increasing distance between obstacle location from the ignition location as well as in several obstacles.展开更多
The main objective of the present study was introduced water mist suppressiontechnology to prevent and control gas burning which occurred during drilling at Wu20160working-face in No.10 coal mine of Pingdingshan Ltd.....The main objective of the present study was introduced water mist suppressiontechnology to prevent and control gas burning which occurred during drilling at Wu20160working-face in No.10 coal mine of Pingdingshan Ltd..Based on the self-developed ex-periment platform,a series of fire suppression tests to evaluate the performance of a watermist system were conducted.The detailed measurements of the spray characteristics,i.e.,the Sauter Mean Diameter(SMD),the velocity and spray angle which are the main pa-rameters considered in the Study,were obtained by using LS-2000 Sizer.The amount ofwater consumed and the water flux density distribution over the cross section downstreamthe nozzle exit were measured by cup collector method.The operating pressure of thewater mist nozzle is set to 0.5 MPa,the droplet SMD of 104 pm,the water flux density dis-tribution from 0.71 to 8.47 L/(m^2.min),the average velocity of 2.14 m/s.The experimentalresults show that the averaged time required for extinguishment is 3.14 s,and the corre-sponding amount of water used during fire test is about 0.11 kg.The gas fire suppressionsystem reduces the temperature in combustion chamber of the experimental apparatusbelow the ignition point of the gas,which can effectively avoid the occurrence of the gasfire in coal mine.展开更多
文摘Nano particles lanthanum modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO 2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at various temperature. XRD and SEM show that the prepared films have good crystallization behavior and perovskite structure. The crystallite is about 60 nm. The deposition speed is 3 nm/min. This deposition method can exactly control stoichiometry ratios, doping concentration ratio and thickness of PLT thin films. The best annealing process is to bake at 300 ℃ for 10 min and anneal at 600 ℃ for 1 h.
文摘Nujiang farmers use the innovative dryland rice cultivation technology developed by a Chinese expert team to grow yields and income.As April ushers in spring,mist clings to the deep valleys of the Nujiang Grand Canyon in Southwest China’s Yunnan Province.High on a mountainside in Ziji Village,Daxingdi Town,Lushui City,Nujiang Lisu Autonomous Prefecture,at an altitude exceeding 1,300 metres,62-year-old Lisu villager Cha Wenxing is planting rice.These demonstration plots,cultivating high-quality upland rice,seem to float amongst the clouds.
文摘As 1.5 million wildebeest pierce the dawn mist of the East African Rift Valley and the roar of lions merges with the cry of zebras beneath sprawling acacia trees,this land unveils life at its rawest-majestic and achingly fragile.
文摘“It's coming!”Liu Fuhai shouted,lying prone on a rock,one of his eyes pressed against his camera.Beads of sweat could be seen on his forehead.Roaring water in the Yellow River plunged from the cliff,making gigantic splashes(落水声)which eventually turned into thick mists.Liu,holding his breath,clicked the shutter quickly to capture the grandeur of the Hukou Waterfall,the largest waterfall on the Yellow River.
基金supported by the National Natural Science Foundation of China(grant numbers:52201334)sup-ported by National Key Laboratory of Ship Structural Safety(grant numbers:Naklas2024-KF015-s).
文摘To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.
文摘The role of cold nitrogen gas and oil mist on tool wear and surface roughness is investigated in turning the K424 nickel-base super alloy with Sialon and SiC whisker-reinforced alumina ceramic tools. A new cooling system is developed and used to lower the temperature of the compressed nitrogen gas. Experiments are performed in three different cooling/lubrication modes, i.e. the dry cutting, the cold nitrogen gas （CNG）, and the cold nitrogen gas and oil mist （CNGOM）. Experimental results show that the depth-of-cut notching severely limits the tool life in all the cooling/lubrication modes. Compared with the dry cutting, the use of CNG and CNGOMcan yield higher wear rate of depth-of-cut notching and worse surface finish.
文摘Green manufacturing （GM） and high efficiency machining technology are inevitable trends in the field of advanced manufacturing of the 21st century. To ensure green and high-efficiency machining, a new high efficiency cooling technology-cryogenic pneumatic mist jet impinging cooling （CPMJI） technology is presented. For obtaining the best cooling effect, a little quantity of coolant is carried by high speed cryogenic air （-20 C ） and reaches the machining zone in the form of mist jet to enhance heat transfer. Experimental results indicate that under the conditions of 40 m/s in the jet impinging speed and 10 mm in the jet impinging distance, the critical heat flux（CHF） nearly reaches 6× 10^7 W/m^2, more than six times of the CHF of the grinding burn with a value of （8～10）×10^6 W/m^2.
基金funded by the Kadoorie Farm and Botanical Garden and the Hong Kong Special Administrative Region,China
文摘To understand better the impact on mist net capture rates of the activity height of birds, light intensity, bird richness and abundance, we compared data from mist nets and point counts at the Jianfengling Forest Area, Hainan Island. Mist-nets were operated for a total of 7135 net-hours. A total of 587 individuals of 45 bird species were captured. The total mean capture rate was 8.6 ± 10.4 per 100 net-hours. A total of 4932 individuals of 107 bird species were recorded by visual observation alone and 7616 individuals of 120 species were recorded in a visual and aural combination. The Grey-cheeked Fulvetta (Alcippe morrisonia) was the most abundant species, accounting for 38.7% of total captures, 27.9% of visual observations and 22.2% of visual + aural observations. The capture number was correlated with the number observed. Thirty-one species were more likely to be captured than observed. Canopy species, such as members of the Corvidae and Dicruridae, were seldom captured. For all ground feeding species, the capture number was greater than that of observation. Some cryptic species, such as the Lesser Wren Babbler (Napothera epilepidota), Spotnecked Babbler (Stachyris striolata) and Cuckoo Owl (Glaucidium cuculoides) also had a higher relative capture rate than that of observations. There was a significant relationship between light intensity and the number of birds captured.
文摘（上接《IS0/TC8与IM0要求的关系及其国际标准-2》[1-2]）ISO16437：2012 船舶与海上技术-救生与防火-船舶油雾探测器（Ships and marine technology-Lifesaving and fire protection--Atmospheric oil mist detectors for
文摘The effects of a fine water mist environment in a semi-confined blast chamber on the chemical and thermodynamic processes following detonation of a 20 g PE4 explosive charge have been investigated.The effects were quantified by the analysis of pressure profiles recorded where several parameters including arrival time of the shock at the sensors, peak overpressures, specific impulse of the positive phase, period of the negative phase and the specific impulse of the multiple reflections were quantified.The effect of the fine water mist on the arrival time, peak pressures and the specific impulse of the positive phase agrees with previous findings in literature. In this paper, the focus is on the implications of the fine water mist on the negative phase and the impulse of multiple pressure reflections. The period of the negative phase was found to have increased by 40% and with higher negative peak pressure in the mist condition compared to the atmospheric condition. The activities of the multiple pressure reflections were found to have decreased considerably, both in number and in amplitude leading to lower impulses(by about 60%) for the water mist conditions.
基金Supported by the Key Technologies R&D Program of Tianjin(15ZCZDSF00550)the“Strengthen Police Force by Science and Technology” Special Foundation on Basic Research of Ministry of Public Security(2015GABJC28)the Key Technical Research Plan of Ministry of Public Security(2017JSYJA13).
文摘To enhance the explosion suppression effects of water mist, various potassium halide additives were tested in a confined vessel filled with a 10% mixture of methane/air. Air and CO2(0.7 MPa) were used as driver gases. The results revealed that halide additives exhibit considerable suppression effects on explosion overpressure. A30% KI mist decreased the explosion overpressure by 27.46% compared with the suppression by pure water mist under the same conditions. When CO2 is used as the driver gas, it will dissolve in water under high pressure.The synergistic effect of a CO2 solution with an effective additive afforded significant suppression. Under the same conditions, the overpressures suppressed by a mist of 30% KI + 0.7 MPa CO2 solution decreased by 33.53% compared with those suppressed by pure water mist driven by air. The synergistic suppression effect is much better than that of a 0.7 MPa CO2 solution mist or 30% KI mist alone. The multicomponent additives can be considered when suppressing methane/air explosions with pressure-formed water mist.
基金financial supports of the National Key Research and Development Program of China(2018YFC0808103)the National Natural Science Foundation of China (51774115, 51604095)。
文摘Combined effects of obstacles and fine water mist on a methane-air explosion of a semi-closed pipe were investigated experimentally.In this study,the diameter of the water mist,the location,and the number of obstacles was considered.The results demonstrated that 5 μm water mist present a significant suppression affected while 45 μm shows a slight promotion effected on a gas explosion of the condition without obstacles.In the presence of an obstacle,however,the inhibitory effect of 5 μm water veils of mist dropped significantly during flame propagation,and the effect of 45 μm water veils of mist changed from the enhancement of inhibition,and its inhibitory effect was significant.The inhibitory effect of 45 μm water veils of mist on gas explosion weakened firstly and then enhanced with the increasing distance between obstacle location from the ignition location as well as in several obstacles.
基金Supported by the Natural Science Foundation of China(50274061,50476033)The Outstanding Talents Innovative Foundation of Henan Province of China(421000800)the Natural Science Foundation of HPU(646102)
文摘The main objective of the present study was introduced water mist suppressiontechnology to prevent and control gas burning which occurred during drilling at Wu20160working-face in No.10 coal mine of Pingdingshan Ltd..Based on the self-developed ex-periment platform,a series of fire suppression tests to evaluate the performance of a watermist system were conducted.The detailed measurements of the spray characteristics,i.e.,the Sauter Mean Diameter(SMD),the velocity and spray angle which are the main pa-rameters considered in the Study,were obtained by using LS-2000 Sizer.The amount ofwater consumed and the water flux density distribution over the cross section downstreamthe nozzle exit were measured by cup collector method.The operating pressure of thewater mist nozzle is set to 0.5 MPa,the droplet SMD of 104 pm,the water flux density dis-tribution from 0.71 to 8.47 L/(m^2.min),the average velocity of 2.14 m/s.The experimentalresults show that the averaged time required for extinguishment is 3.14 s,and the corre-sponding amount of water used during fire test is about 0.11 kg.The gas fire suppressionsystem reduces the temperature in combustion chamber of the experimental apparatusbelow the ignition point of the gas,which can effectively avoid the occurrence of the gasfire in coal mine.
