Yeats' lyrics of sublimation is one of his major concerns in his later years. Sublimation for Yeats is essentially the transmutation and elevation of bitterness and tragic facts of being into happiness, into tranq...Yeats' lyrics of sublimation is one of his major concerns in his later years. Sublimation for Yeats is essentially the transmutation and elevation of bitterness and tragic facts of being into happiness, into tranquility of mind, then into the emotionless emotion, as Yeats names it as "innocence". The process of sublimation enriches the creativity of Yeats as artist when he is confronted with severity of aging spiritually and physically.展开更多
High-resolution X-ray diffractometry(HRXRD)was used to assess the quality of 6H-SiC crystals grown by sublimation method.The results show the occurrence of low-angle grain boundaries(LB)is close relative to the inclin...High-resolution X-ray diffractometry(HRXRD)was used to assess the quality of 6H-SiC crystals grown by sublimation method.The results show the occurrence of low-angle grain boundaries(LB)is close relative to the inclination of the crystal interface.At the central faceted region with 0°inclination the crystal is of high structural perfection.However,at the region close to the facet with less than 5°inclination LB occurs slightly and at the region close to the peripheral polytype ring with more than 5°inclination LB defect occurs heavily.The density of LB can be drastically reduced by decreasing radial temperature gradient that determines the shape of the crystal growth interface.展开更多
The thermo physical parameters of Tm vapor and the range of sublimation temperature were determined by vapor pressure of metal Tm, and a 2-D axis-symmetric heat transfer model was developed to investigate the temperat...The thermo physical parameters of Tm vapor and the range of sublimation temperature were determined by vapor pressure of metal Tm, and a 2-D axis-symmetric heat transfer model was developed to investigate the temperature distribution in sublimation furnace. The simulation results showed that, due to the heat loss at crucible bottom, the temperature of crucible, solid metal and Tm vapor increased with crucible height increasing, reached the maximum value in the middle of crucible in height direction, and then decreased rapidly; at the outside surface of condenser, the temperature decreased sharply; with heating body temperature of 1000oC, the mean temperature at upper surface of solid Tm was 22oC higher than that on the lower surface, the mean temperature of upper surface of solid Tm was about 32oC lower than that of heating body, and the calculated sublimation velocity was 8.16g/cm2/h, which was only 54.4% of sublimation velocity calculation by heating body temperature.展开更多
The lunar surface is a typical vacuum environment,and its harsh heat rejection conditions bring great challenges to the thermal control technology of the exploration mission.In addition to the radiator,the sublimator ...The lunar surface is a typical vacuum environment,and its harsh heat rejection conditions bring great challenges to the thermal control technology of the exploration mission.In addition to the radiator,the sublimator is recommended as one of the promising options for heat rejection.The sublimator makes use of water to freeze and sublimate in a porous medium,rejecting heat to the vacuum environment.The complex heat and mass transfer process involves many physical phenomena such as the freezing and sublimation phase change of water in the porous medium and the movement of the phase-change interface.In this paper,the visualized ground-based experimental approaches of space sublimation cooling were presented to reveal the moving law of threephase point and the growth phenomenon of ice-peak and icicle in microchannels under vacuum conditions.The visualized experiments and results prove that the freezing ice is divided into the porous ice-peak and the transparent icicle.As the sublimation progresses,the phase-change interface moves downward steadily,the length of the ice-peak increases,but the icicle decreases.The visualized experiments of space sublimation cooling in the capillary have guiding significance to reveal the sublimation cooling mechanism of water in the sublimator for lunar exploration missions.展开更多
Close-space sublimation(CSS)has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes(OLEDs).CSS utilizes a planar donor plate pre-coated with organic thin films...Close-space sublimation(CSS)has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes(OLEDs).CSS utilizes a planar donor plate pre-coated with organic thin films as an area source to rapidly transfer the donor film to a device substrate at temperatures below 200℃.CSS is also conformal and capable of depositing on odd-shaped substrates using flexible donor media.The evaporation behaviors of organic donor films under CSS were fully characterized using model OLED materials and CSS-deposited films exhibited comparable device performances in an OLED stack to films deposited by conventional point sources.The low temperature and conformal nature of CSS,along with its high material utilization and short process time,make it a promising method for fabricating flexible OLED displays.展开更多
Drying is an important unit operation in processing of biological resources. The drying process may influence the product properties and quality, which may shrink, break or undergo rheological, physical and biochemica...Drying is an important unit operation in processing of biological resources. The drying process may influence the product properties and quality, which may shrink, break or undergo rheological, physical and biochemical changes. The important parameters responsible for such changes are drying conditions, type of drying technology and residence drying time. Thermal conductivity, thermal-mass diffusivity, enthalpy, porosity and density are the main material property and heat-mass transfer parameters, which are essential for understanding the changes in product quality and for designing and dimensioning the drying processes. In this paper physical properties of food products undergoing a combined sublimation and evaporation were studied. Pieces of vegetables and potatoes were dried in a heat pump fluidized bed dryer at combined modes with temperatures below the freezing point in the beginning and a final drying step at temperatures above the freezing point. Samples of products were tested at different moisture contents with respect to physical properties. Physical properties of leek and potato samples were measured and mass diffusivities were determined from drying kinetic data. Based on bulk density and rehydration measurements it was clearly observed that drying temperature and modes influenced the final product physical properties. The potato cube run dried with initial atmospheric freeze-drying step had rehydration ability 430%above a run dried only above the freezing point. The average effective mass diffusivity for 5 mm slabs of leek was 0.5 x 10-11m2·s-1 for the sublimation stage and 2.2 x 10-11m2·s-1 for the evaporation stage.展开更多
CdTe films are prepared by closed-space sublimation technology. Dependence of film crystalline on substrate materials and substrate temperature is investigated. It is found that films exhibit higher crystallinity at s...CdTe films are prepared by closed-space sublimation technology. Dependence of film crystalline on substrate materials and substrate temperature is investigated. It is found that films exhibit higher crystallinity at substrate temperature higher than 400 ℃. And the CdTe films deposited on CdS films with higher crystallinity have bigger crystallite and higher uniformity. Treatment with CdCl 2 methanol solution promotes the crystallite growth of CdTe films during annealing.展开更多
Thin films of Zn1-xCuxSe （x= 0.00, 0.05, 0.10, 0.15, 0.20） were grown on glass substrates by closed space sublimation technique. The deposited films were annealed at 200 ~C and 400 ~C in air for 1 h. The annealed sa...Thin films of Zn1-xCuxSe （x= 0.00, 0.05, 0.10, 0.15, 0.20） were grown on glass substrates by closed space sublimation technique. The deposited films were annealed at 200 ~C and 400 ~C in air for 1 h. The annealed samples have been investigated through Rutherford backscattering spectroscopy （RBS）, X-ray diffraction （XRD）, spectroscopic ellipsometer, spectrophotometer and Raman spectroscopy. Through RBS, the composition of the films was calculated and compared with the initial concentration. Structural characteriza- tion including crystal structure, crystal orientation, lattice parameter, grain size, strain and dislocation density were carried out using XRD data. From XRD spectra it was revealed that the as-deposited and annealed films were polycrystalline in nature with zinc-blende structure. However, the crystallinity and the grain size were improved with the increase of annealing temperature. According to Raman spectroscopy, it was observed that as deposited and annealed samples have the same characteristic vibrational modes of ZnSe at low and high frequency optical phonon modes while another mode was observed for 400 ℃ annealed samples at 745 cm-1. Spectroscopic ellipsometer has been used to found annealing effect on the optical properties of ZnSe. The band gap energy has been determined using transmission spectra. It was found that the band gap energy of the film increased with the increase of annealing temperature.展开更多
A novel design of crucible is proposed in this paper for the growth of SiC crystals. The relation between grown crystal shape and temperature distribution in a growth chamber was discussed. It is pointed out that the ...A novel design of crucible is proposed in this paper for the growth of SiC crystals. The relation between grown crystal shape and temperature distribution in a growth chamber was discussed. It is pointed out that the crystal shape had a close relationship with temperature distribution. The calculations suggested that the radial temperature field of the growing crystal became homogenous by setting up the cone-shaped baffle in the growth chamber. By modifying the crucible design and temperature distribution in the growth chamber, it is possible to enhance the enlargement of crystal, and also possible to keep grown surface flat.展开更多
Based on the linearity of the heat transfer coefficient and dimensionless temperature ratio, and analogy between heat and mass transfer, an experimental study on film cooling characteristic was carried out with a nove...Based on the linearity of the heat transfer coefficient and dimensionless temperature ratio, and analogy between heat and mass transfer, an experimental study on film cooling characteristic was carried out with a novel naphthalene sublimation. In general, cooling effectiveness distributions have been obtained on adiabatic surface, but separate testing on a non adiabatic wall is required to determine the heat transfer coefficient distribution. This novel naphthalene sublimation, which is different from previous heat transfer or analogy method, can measure both cooling effectiveness and heat transfer coefficient together with the same test section. The results show well by being compared with other references.展开更多
This paper attempts to demonstrate Hester Prynne＇s, in Nathaniel Hawthorne＇s romantic work of fiction The Scarlet Letter （1994）, sublimation of her sexual impulses into identifying with the socially acceptable hum...This paper attempts to demonstrate Hester Prynne＇s, in Nathaniel Hawthorne＇s romantic work of fiction The Scarlet Letter （1994）, sublimation of her sexual impulses into identifying with the socially acceptable humanitarian actions, and societal demands in order to avoid the confrontation with the scorn of the people of Boston, her sexual urge, and with her weakness. Hester＇s libidinal energy was channeled into socially approved activities in her self-devoted years that made up her identity and reality. The scarlet letter ceased to be a stigma which once attracted the world＇s scorn and bitterness, later looked upon with reverence, and transformed into a thing to be sorrowed over. She had not ignored a large part of reality of her life （the past and present）. If she ignored her past she would entirely detach it from the present. She integrated her stigma into her life in the continual process of self-making, and thereby projecting herself into the future展开更多
An individual suspended graphene sheet was connected to a scanning tunneling microscopy probe inside a transmission electron microscope,and Joule heated to high temperatures.At high temperatures and under electron bea...An individual suspended graphene sheet was connected to a scanning tunneling microscopy probe inside a transmission electron microscope,and Joule heated to high temperatures.At high temperatures and under electron beam irradiation,the few-layer graphene sheets were removed layer-by-layer in the viewing area until a monolayer graphene was formed.The layer-by-layer peeling was initiated at vacancies in individual graphene layers.The vacancies expanded to form nanometer-sized holes,which then grew along the perimeter and propagated to both the top and bottom layers of a bilayer graphene joined by a bilayer edge.The layer-by-layer peeling was induced by atom sublimation caused by Joule heating and facilitated by atom displacement caused by high-energy electron irradiation,and may be harnessed to control the layer thickness of graphene for device applications.展开更多
A sublimation condensation model is developed for microwave freeze drying of unsaturated porous media. The transport properties in the model are analyzed and the model is calculated numerically for the microwave freez...A sublimation condensation model is developed for microwave freeze drying of unsaturated porous media. The transport properties in the model are analyzed and the model is calculated numerically for the microwave freeze drying of unsaturated porous media. The results show that the effects of sublimation condensation region on drying processes are significant as compared with the traditional sublimation interface model.展开更多
Introduction Pd/Ti double-layer thin film as non-evaporable getter(NEG)was deposited by sublimation,and its activation temperature was as low as 100℃.The Pd film was deposited in situ after Ti deposition to ensure no...Introduction Pd/Ti double-layer thin film as non-evaporable getter(NEG)was deposited by sublimation,and its activation temperature was as low as 100℃.The Pd film was deposited in situ after Ti deposition to ensure no oxidization on Ti film.Pumping speed test and characterization method The pumping speed of the coated pipe was measured by a pumping speed test system.The sticking factor was calculated by Molflow.The surface morphology was observed by a scanning electron microscope(SEM).The chemical composition of the film was measured by an energy-dispersive spectrum inbuilt with the SEM.The crystalline structure of the film was measured using grazing incidence X-ray diffraction.Conclusion It was found that the pumping performance of the Pd/Ti film still remained high after 15 times of activation.The maximum pumping speed after heating at 100℃for 24 h was 1.1 L/s cm^(2)and 0.49 L/s cm^(2)for H_(2)and CO,respectively.It can be concluded that the key to reducing the activation temperature of NEG materials is to enhance the oxidation resistance of the surface of NEG.展开更多
Using films by Patricia Rozema and Igmar Bergman,“Lowering Human Hubris into the Sublime”reminds the reader that the particular in our lives is where the sublime performs.While we multitask and take for granted the ...Using films by Patricia Rozema and Igmar Bergman,“Lowering Human Hubris into the Sublime”reminds the reader that the particular in our lives is where the sublime performs.While we multitask and take for granted the world around us that supports our mythic assumptions,the particular objects and lives are actively present.In the two movies,the particular functions as a source of the sublime reminder and source of metaphor for stability and atrophy in everyday living.In one film an artist focuses the ordinary objects in everyday life while being disregarded by artists involved in the abstract.In the second film the particular behind the scenes works quietly to dismantle cultural beliefs for the people living the soon to be dated beliefs where opportunities for more inclusive community reside.展开更多
The Book of Songs is the first collection of poems in China,originally named Poetry,and is one of the Five Classics.Whether in terms of themes,thoughts and emotions,language skills,as well as in artistic images and ex...The Book of Songs is the first collection of poems in China,originally named Poetry,and is one of the Five Classics.Whether in terms of themes,thoughts and emotions,language skills,as well as in artistic images and expression methods,it has shown the great achievements of China’s earliest poetry works and has produced a profound influence on Chinese culture and literature.It not only has recorded the various aspects of the society of that time,but also opens the door to many literary studies.There is no need to argue about its status and significance.In the West,about twelve centuries after the creation of the first poem collected in The Book of Songs,there lived a literary theorist who has performed a great influence on western literature.He was Longinus,the author of On the Sublime.By comparing the aesthetic ideas of Longinus and the artistic characteristics of The Book of Songs,we are surprised to find that The Book of Songs is a paragon of the sublime described by Longinus.展开更多
Chen Duxiu’S political career might be said to have been awakened by the Sino.Japanese War(1 894—95),and it ended,or rather.underwent a final awakening.in themidst of the Chinese nation’S War of Resistance against ...Chen Duxiu’S political career might be said to have been awakened by the Sino.Japanese War(1 894—95),and it ended,or rather.underwent a final awakening.in themidst of the Chinese nation’S War of Resistance against Japan.展开更多
In this work, comprehensive studies of 2,4-dinitroanisole(2,4DNAN) were carried out using powder thermorentgenography of the internal standard. The time of the complete polymorphic transition in the solid phase β→a ...In this work, comprehensive studies of 2,4-dinitroanisole(2,4DNAN) were carried out using powder thermorentgenography of the internal standard. The time of the complete polymorphic transition in the solid phase β→a in 2,4DNAN under various combinations of conditions has been determined. It has been established that, regardless of the season of manufacture of the substance, when it is stored for 8-9months, with a change in ambient temperature from minus 30℃ to plus 30℃, a complete polymorphic transition β→a occurs. When stored in conditions below minus 5℃, polymorphic transition does not occur. When stored in conditions above plus 30℃ in a closed container, polymorphic transition occurs within 3 weeks. The polymorphic transition is accompanied by a decrease in density by 1.3%-1.5% and an increase in melting temperature by 10-12℃, depending on the degree of purity of the starting substance. The activation energy of the molecular rearrangement was 68-70 k J/mol(16.5 ± 3 kcal/mol). The mechanism of polymorphic transition has been evaluated, which is presumably based on internal homodiffusion and energy transfer to the surface of the mass of powder particles and the product. The average activation energy of the polymorphic transition process was 110 ± 6.2 k J/mol(26.2 kcal/mol). In an open container, reactions proceed by a homogeneous mechanism, and in a closed container by a heterogeneous mechanism involving the gas phase.展开更多
Crystallization,while a common process in nature,remains one of the most mysterious phenomena.Understanding its physical mechanisms is essential for obtaining high-quality crystals.Typically,crystals grown by thermal ...Crystallization,while a common process in nature,remains one of the most mysterious phenomena.Understanding its physical mechanisms is essential for obtaining high-quality crystals.Typically,crystals grown by thermal evaporation or sublimation nucleate the substrate facing the evaporation source.Here,a novel vapor micro-turbulence mass transport mechanism in the growth process of ultrathin BiOCl single crystals has been revealed.In this mechanism,the precursor vapor bypasses the solid substrate,forming micro-turbulent vaporizing flows to nucleate on the surface of the substrate facing away from the evaporation source.Considering nucleation kinetics,fast shear flows are known to cause secondary nucleation,increasing nucleation quantity while decreasing the final size of the crystals.Thus,the nucleation and growth process of BiOCl crystals are controlled by adjusting the micro-turbulence intensity to reduce shear flow energy and dilate phase distribution,resulting in BiOCl crystals with uniform distribution and regular shape.Subsequent structural and morphological characterization confirms the high crystallization quality of the obtained crystals,and the performance of the constructed solar-blind photodetectors is comparable to that of similar devices.These findings contribute to a deeper understanding of vapor mass transport and crystal growth techniques and may be useful for applications related to metal oxide crystals.展开更多
文摘Yeats' lyrics of sublimation is one of his major concerns in his later years. Sublimation for Yeats is essentially the transmutation and elevation of bitterness and tragic facts of being into happiness, into tranquility of mind, then into the emotionless emotion, as Yeats names it as "innocence". The process of sublimation enriches the creativity of Yeats as artist when he is confronted with severity of aging spiritually and physically.
基金Project supported National Natural Science Foundation of China(60025409 and 50472068)National"863"High Technology Plan(2001AA311080)
文摘High-resolution X-ray diffractometry(HRXRD)was used to assess the quality of 6H-SiC crystals grown by sublimation method.The results show the occurrence of low-angle grain boundaries(LB)is close relative to the inclination of the crystal interface.At the central faceted region with 0°inclination the crystal is of high structural perfection.However,at the region close to the facet with less than 5°inclination LB occurs slightly and at the region close to the peripheral polytype ring with more than 5°inclination LB defect occurs heavily.The density of LB can be drastically reduced by decreasing radial temperature gradient that determines the shape of the crystal growth interface.
基金Project supported by National Hi-Tech R&D Program of China(863Program,2011AA03A409)Major State Basic Research Development Program of China(973Program,2012BA01207)
文摘The thermo physical parameters of Tm vapor and the range of sublimation temperature were determined by vapor pressure of metal Tm, and a 2-D axis-symmetric heat transfer model was developed to investigate the temperature distribution in sublimation furnace. The simulation results showed that, due to the heat loss at crucible bottom, the temperature of crucible, solid metal and Tm vapor increased with crucible height increasing, reached the maximum value in the middle of crucible in height direction, and then decreased rapidly; at the outside surface of condenser, the temperature decreased sharply; with heating body temperature of 1000oC, the mean temperature at upper surface of solid Tm was 22oC higher than that on the lower surface, the mean temperature of upper surface of solid Tm was about 32oC lower than that of heating body, and the calculated sublimation velocity was 8.16g/cm2/h, which was only 54.4% of sublimation velocity calculation by heating body temperature.
基金primarily funded by the cooperative project offered by Beijing Key Laboratory of Space Thermal Control Technologyfunded by China Postdoctoral Science Foundation(No.2020 M671618)。
文摘The lunar surface is a typical vacuum environment,and its harsh heat rejection conditions bring great challenges to the thermal control technology of the exploration mission.In addition to the radiator,the sublimator is recommended as one of the promising options for heat rejection.The sublimator makes use of water to freeze and sublimate in a porous medium,rejecting heat to the vacuum environment.The complex heat and mass transfer process involves many physical phenomena such as the freezing and sublimation phase change of water in the porous medium and the movement of the phase-change interface.In this paper,the visualized ground-based experimental approaches of space sublimation cooling were presented to reveal the moving law of threephase point and the growth phenomenon of ice-peak and icicle in microchannels under vacuum conditions.The visualized experiments and results prove that the freezing ice is divided into the porous ice-peak and the transparent icicle.As the sublimation progresses,the phase-change interface moves downward steadily,the length of the ice-peak increases,but the icicle decreases.The visualized experiments of space sublimation cooling in the capillary have guiding significance to reveal the sublimation cooling mechanism of water in the sublimator for lunar exploration missions.
基金financially supported by the General Research Fund(16309918)from the Research Grant Council,Hong Kongfunding from the Institute for Advanced Study of the Hong Kong University of Science and Technology。
文摘Close-space sublimation(CSS)has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes(OLEDs).CSS utilizes a planar donor plate pre-coated with organic thin films as an area source to rapidly transfer the donor film to a device substrate at temperatures below 200℃.CSS is also conformal and capable of depositing on odd-shaped substrates using flexible donor media.The evaporation behaviors of organic donor films under CSS were fully characterized using model OLED materials and CSS-deposited films exhibited comparable device performances in an OLED stack to films deposited by conventional point sources.The low temperature and conformal nature of CSS,along with its high material utilization and short process time,make it a promising method for fabricating flexible OLED displays.
文摘Drying is an important unit operation in processing of biological resources. The drying process may influence the product properties and quality, which may shrink, break or undergo rheological, physical and biochemical changes. The important parameters responsible for such changes are drying conditions, type of drying technology and residence drying time. Thermal conductivity, thermal-mass diffusivity, enthalpy, porosity and density are the main material property and heat-mass transfer parameters, which are essential for understanding the changes in product quality and for designing and dimensioning the drying processes. In this paper physical properties of food products undergoing a combined sublimation and evaporation were studied. Pieces of vegetables and potatoes were dried in a heat pump fluidized bed dryer at combined modes with temperatures below the freezing point in the beginning and a final drying step at temperatures above the freezing point. Samples of products were tested at different moisture contents with respect to physical properties. Physical properties of leek and potato samples were measured and mass diffusivities were determined from drying kinetic data. Based on bulk density and rehydration measurements it was clearly observed that drying temperature and modes influenced the final product physical properties. The potato cube run dried with initial atmospheric freeze-drying step had rehydration ability 430%above a run dried only above the freezing point. The average effective mass diffusivity for 5 mm slabs of leek was 0.5 x 10-11m2·s-1 for the sublimation stage and 2.2 x 10-11m2·s-1 for the evaporation stage.
文摘CdTe films are prepared by closed-space sublimation technology. Dependence of film crystalline on substrate materials and substrate temperature is investigated. It is found that films exhibit higher crystallinity at substrate temperature higher than 400 ℃. And the CdTe films deposited on CdS films with higher crystallinity have bigger crystallite and higher uniformity. Treatment with CdCl 2 methanol solution promotes the crystallite growth of CdTe films during annealing.
文摘Thin films of Zn1-xCuxSe （x= 0.00, 0.05, 0.10, 0.15, 0.20） were grown on glass substrates by closed space sublimation technique. The deposited films were annealed at 200 ~C and 400 ~C in air for 1 h. The annealed samples have been investigated through Rutherford backscattering spectroscopy （RBS）, X-ray diffraction （XRD）, spectroscopic ellipsometer, spectrophotometer and Raman spectroscopy. Through RBS, the composition of the films was calculated and compared with the initial concentration. Structural characteriza- tion including crystal structure, crystal orientation, lattice parameter, grain size, strain and dislocation density were carried out using XRD data. From XRD spectra it was revealed that the as-deposited and annealed films were polycrystalline in nature with zinc-blende structure. However, the crystallinity and the grain size were improved with the increase of annealing temperature. According to Raman spectroscopy, it was observed that as deposited and annealed samples have the same characteristic vibrational modes of ZnSe at low and high frequency optical phonon modes while another mode was observed for 400 ℃ annealed samples at 745 cm-1. Spectroscopic ellipsometer has been used to found annealing effect on the optical properties of ZnSe. The band gap energy has been determined using transmission spectra. It was found that the band gap energy of the film increased with the increase of annealing temperature.
文摘A novel design of crucible is proposed in this paper for the growth of SiC crystals. The relation between grown crystal shape and temperature distribution in a growth chamber was discussed. It is pointed out that the crystal shape had a close relationship with temperature distribution. The calculations suggested that the radial temperature field of the growing crystal became homogenous by setting up the cone-shaped baffle in the growth chamber. By modifying the crucible design and temperature distribution in the growth chamber, it is possible to enhance the enlargement of crystal, and also possible to keep grown surface flat.
文摘Based on the linearity of the heat transfer coefficient and dimensionless temperature ratio, and analogy between heat and mass transfer, an experimental study on film cooling characteristic was carried out with a novel naphthalene sublimation. In general, cooling effectiveness distributions have been obtained on adiabatic surface, but separate testing on a non adiabatic wall is required to determine the heat transfer coefficient distribution. This novel naphthalene sublimation, which is different from previous heat transfer or analogy method, can measure both cooling effectiveness and heat transfer coefficient together with the same test section. The results show well by being compared with other references.
文摘This paper attempts to demonstrate Hester Prynne＇s, in Nathaniel Hawthorne＇s romantic work of fiction The Scarlet Letter （1994）, sublimation of her sexual impulses into identifying with the socially acceptable humanitarian actions, and societal demands in order to avoid the confrontation with the scorn of the people of Boston, her sexual urge, and with her weakness. Hester＇s libidinal energy was channeled into socially approved activities in her self-devoted years that made up her identity and reality. The scarlet letter ceased to be a stigma which once attracted the world＇s scorn and bitterness, later looked upon with reverence, and transformed into a thing to be sorrowed over. She had not ignored a large part of reality of her life （the past and present）. If she ignored her past she would entirely detach it from the present. She integrated her stigma into her life in the continual process of self-making, and thereby projecting herself into the future
基金This work was performed,in part,at the Center for Integrated Nanotechnologies,the U.S.Department of Energy,Office of Basic Energy Sciences user facility.Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation,a Lockheed-Martin Company,for the U.S.Department of Energy under Contract No.DE-AC04-94AL85000JL would like to acknowledge support by Honda Research Institute USA,NSF CMMI-0728069,AFOSR,and ONR N00014-05-1-0504J.Y.H.would like to thank Dr.Ping Lu at Sandia National Laboratories for conducting the HRTEM image simulations.
文摘An individual suspended graphene sheet was connected to a scanning tunneling microscopy probe inside a transmission electron microscope,and Joule heated to high temperatures.At high temperatures and under electron beam irradiation,the few-layer graphene sheets were removed layer-by-layer in the viewing area until a monolayer graphene was formed.The layer-by-layer peeling was initiated at vacancies in individual graphene layers.The vacancies expanded to form nanometer-sized holes,which then grew along the perimeter and propagated to both the top and bottom layers of a bilayer graphene joined by a bilayer edge.The layer-by-layer peeling was induced by atom sublimation caused by Joule heating and facilitated by atom displacement caused by high-energy electron irradiation,and may be harnessed to control the layer thickness of graphene for device applications.
文摘A sublimation condensation model is developed for microwave freeze drying of unsaturated porous media. The transport properties in the model are analyzed and the model is calculated numerically for the microwave freeze drying of unsaturated porous media. The results show that the effects of sublimation condensation region on drying processes are significant as compared with the traditional sublimation interface model.
基金provided by National Development and Reform Commission(Grand No.发改高技(2017)2173号)
文摘Introduction Pd/Ti double-layer thin film as non-evaporable getter(NEG)was deposited by sublimation,and its activation temperature was as low as 100℃.The Pd film was deposited in situ after Ti deposition to ensure no oxidization on Ti film.Pumping speed test and characterization method The pumping speed of the coated pipe was measured by a pumping speed test system.The sticking factor was calculated by Molflow.The surface morphology was observed by a scanning electron microscope(SEM).The chemical composition of the film was measured by an energy-dispersive spectrum inbuilt with the SEM.The crystalline structure of the film was measured using grazing incidence X-ray diffraction.Conclusion It was found that the pumping performance of the Pd/Ti film still remained high after 15 times of activation.The maximum pumping speed after heating at 100℃for 24 h was 1.1 L/s cm^(2)and 0.49 L/s cm^(2)for H_(2)and CO,respectively.It can be concluded that the key to reducing the activation temperature of NEG materials is to enhance the oxidation resistance of the surface of NEG.
文摘Using films by Patricia Rozema and Igmar Bergman,“Lowering Human Hubris into the Sublime”reminds the reader that the particular in our lives is where the sublime performs.While we multitask and take for granted the world around us that supports our mythic assumptions,the particular objects and lives are actively present.In the two movies,the particular functions as a source of the sublime reminder and source of metaphor for stability and atrophy in everyday living.In one film an artist focuses the ordinary objects in everyday life while being disregarded by artists involved in the abstract.In the second film the particular behind the scenes works quietly to dismantle cultural beliefs for the people living the soon to be dated beliefs where opportunities for more inclusive community reside.
文摘The Book of Songs is the first collection of poems in China,originally named Poetry,and is one of the Five Classics.Whether in terms of themes,thoughts and emotions,language skills,as well as in artistic images and expression methods,it has shown the great achievements of China’s earliest poetry works and has produced a profound influence on Chinese culture and literature.It not only has recorded the various aspects of the society of that time,but also opens the door to many literary studies.There is no need to argue about its status and significance.In the West,about twelve centuries after the creation of the first poem collected in The Book of Songs,there lived a literary theorist who has performed a great influence on western literature.He was Longinus,the author of On the Sublime.By comparing the aesthetic ideas of Longinus and the artistic characteristics of The Book of Songs,we are surprised to find that The Book of Songs is a paragon of the sublime described by Longinus.
文摘Chen Duxiu’S political career might be said to have been awakened by the Sino.Japanese War(1 894—95),and it ended,or rather.underwent a final awakening.in themidst of the Chinese nation’S War of Resistance against Japan.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(Agreement with Zelinsky Institute of Organic Chemistry RAS Grant No.075-15-2020-803).
文摘In this work, comprehensive studies of 2,4-dinitroanisole(2,4DNAN) were carried out using powder thermorentgenography of the internal standard. The time of the complete polymorphic transition in the solid phase β→a in 2,4DNAN under various combinations of conditions has been determined. It has been established that, regardless of the season of manufacture of the substance, when it is stored for 8-9months, with a change in ambient temperature from minus 30℃ to plus 30℃, a complete polymorphic transition β→a occurs. When stored in conditions below minus 5℃, polymorphic transition does not occur. When stored in conditions above plus 30℃ in a closed container, polymorphic transition occurs within 3 weeks. The polymorphic transition is accompanied by a decrease in density by 1.3%-1.5% and an increase in melting temperature by 10-12℃, depending on the degree of purity of the starting substance. The activation energy of the molecular rearrangement was 68-70 k J/mol(16.5 ± 3 kcal/mol). The mechanism of polymorphic transition has been evaluated, which is presumably based on internal homodiffusion and energy transfer to the surface of the mass of powder particles and the product. The average activation energy of the polymorphic transition process was 110 ± 6.2 k J/mol(26.2 kcal/mol). In an open container, reactions proceed by a homogeneous mechanism, and in a closed container by a heterogeneous mechanism involving the gas phase.
基金financially supported by Jiangsu Funding Program for Excellent Postdoctoral Talent(Nos.2023ZB695 and 2023ZB167)China Postdoctoral Science Foundation(Nos.2023M742557 and 2023M742561)+2 种基金the National Natural Science Foundation of China(No.52372055)the Basic Research Development Program of Suzhou(No.SJC2023004)Jiangsu Independent Innovation Fund Project of Agricultural Science and Technology(No.CX(21)3163)。
文摘Crystallization,while a common process in nature,remains one of the most mysterious phenomena.Understanding its physical mechanisms is essential for obtaining high-quality crystals.Typically,crystals grown by thermal evaporation or sublimation nucleate the substrate facing the evaporation source.Here,a novel vapor micro-turbulence mass transport mechanism in the growth process of ultrathin BiOCl single crystals has been revealed.In this mechanism,the precursor vapor bypasses the solid substrate,forming micro-turbulent vaporizing flows to nucleate on the surface of the substrate facing away from the evaporation source.Considering nucleation kinetics,fast shear flows are known to cause secondary nucleation,increasing nucleation quantity while decreasing the final size of the crystals.Thus,the nucleation and growth process of BiOCl crystals are controlled by adjusting the micro-turbulence intensity to reduce shear flow energy and dilate phase distribution,resulting in BiOCl crystals with uniform distribution and regular shape.Subsequent structural and morphological characterization confirms the high crystallization quality of the obtained crystals,and the performance of the constructed solar-blind photodetectors is comparable to that of similar devices.These findings contribute to a deeper understanding of vapor mass transport and crystal growth techniques and may be useful for applications related to metal oxide crystals.
