A shard of Chinese underglaze copper-red porcelain from the Yuan dynasty (AD 1271–1368) made in the Jingdezhen kiln was measured by synchrotron radiation- induced X-ray fluorescence mapping and X-ray absorption near-...A shard of Chinese underglaze copper-red porcelain from the Yuan dynasty (AD 1271–1368) made in the Jingdezhen kiln was measured by synchrotron radiation- induced X-ray fluorescence mapping and X-ray absorption near-edge spectroscopy to investigate the influence of copper element distribution and speciation on the color of porcelain. In black-colored region, copper accumulates at the interface between the body and glaze layers with metallic copper particles as the main speciation. In contrast, Cu is irregularly distributed in the red-colored region with multi-valence speciation. The differences in Cu distribution and speciation in black- and red-colored regions indicate that they are the main factors influencing the different colors of copper-red underglaze porcelain.展开更多
In China, the firing and glazed red techniques of producing underglaze-red porcelain began early in the Yuan Dynasty (AD1206~ 1368). This paper reports the results of the PIXE analysis of ancient Chinese underglaze-r...In China, the firing and glazed red techniques of producing underglaze-red porcelain began early in the Yuan Dynasty (AD1206~ 1368). This paper reports the results of the PIXE analysis of ancient Chinese underglaze-red porcelain produced at Kuan kiln (Jingdezhen, Jiangxi Province) in the Yuan Dynasty. In this work the elemental composition analysis of the obtained samples was carried out using the PIXE facility of a 3 MeV tandem accelerator at Fudan University. The major; minor and trace elements of the clay body, white and red glazes were determined,and details of the results are presented. The obtained data can be used for identification of precious Chinese Yuan underglaze-red porcelain.展开更多
A copper-red and silver-white metallic glaze of R_(2)O-RO-Al_(2)O_(3)-SiO_(2)-P_(2)O_(5)system was synthesized by adjusting the firing temperature and glaze components.The coloration mechanism of the metallic glaze wa...A copper-red and silver-white metallic glaze of R_(2)O-RO-Al_(2)O_(3)-SiO_(2)-P_(2)O_(5)system was synthesized by adjusting the firing temperature and glaze components.The coloration mechanism of the metallic glaze was revealed via investigation of the microstructure of the glaze.Our research reveals that the metallic glaze with different colors is mainly due to the amount of Fe_(2)O_(3).The metallic glaze shows a silver-white luster due to a structural color ofα-Fe_(2)O_(3)crystals with a good orientation when the sample contains 0.0939 mol of Fe_(2)O_(3),maintaining temperatures at 1150℃for 0.5 h.The metallic glaze is copper-red which is dominated by the coupling of chemical and structural color ofα-Fe_(2)O_(3)crystals when the sample contains 0.0783 mol of Fe_(2)O_(3).After testing the amount of SiO_(2),we find that 4.0499 mol is the optimal amount to form the ceramic network,and 0.27 mol AlPO_(4)is the best amount to promote phase separation.展开更多
Porcelain electrical equipment (PEE), such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic ...Porcelain electrical equipment (PEE), such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers (MTMD). An MTMD damping device involving three mass units, named a triple tuned mass damper (TTMD), is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.展开更多
The characteristics of broken surfaces were r esearched by a scanning electron microscope (SEM) and a reflection microscope, a nd the fractal dimensions of broken surfaces were measured by the Slit Island me thod. Th...The characteristics of broken surfaces were r esearched by a scanning electron microscope (SEM) and a reflection microscope, a nd the fractal dimensions of broken surfaces were measured by the Slit Island me thod. The experimental results indicate that the broken surface of aluminum elec tric porcelain is a fractal body in statistics, and the fractal dimensions of br oken surfaces are different with the different amplification multiple value.In a ll of measured fractal dimensions,both of values measured in 100× under reflect ion microscope and in 500× under SEM are maximum, whereas the values measur ed in 63× under reflection microscope and in 2000× under SEM are obviously min imum. The fractal dimensions of broken surfaces are also affected by the degrees of gray comparison and the kinds of measuring methods. The relationships betwee n the fractal dimensions of broken surfaces and porcelain bend strengths are tha t they are in positive correlation on the low multiples and in negative correlat ion on the high multiples.展开更多
Usually the thermal expansion coefficients (TEC) of metals are higher than that of porcelains. In order to match the TECs in the case of coating porcelains on metals, high TEC porcelains are needed. In this research, ...Usually the thermal expansion coefficients (TEC) of metals are higher than that of porcelains. In order to match the TECs in the case of coating porcelains on metals, high TEC porcelains are needed. In this research, the high TEC phase leucite (KAlSi2 O6) in the high TEC porcelain was prepared by sol-gel method. The crystal size of leucite made by sol-gel is about 77nm through controlling the process parameters. The process from xerogel to leucite was investigated by means of DSC (differential scanning calorimetry), TG (thermogravimetry), XRD ( X-ray diffraction) and IR (infrared absorption spectrum). Leucite had been detected after the gel was treated at 900℃, this formation temperature is about 250℃ lower than that of melting method. The porcelain made from 50% of the leucite powder and 50% of low fused temperature frit has an average TEC of 19.2×10-6/℃ C from room temperature to 450℃, which is much higher than the common porcelains.展开更多
Bauxite porcelain can be sintered to make its bending strength reach 179Mpa by using sintered bauxite, clay and potash feldspar and albite as the main raw materials in oxidation atmosphere under the normal pressure. X...Bauxite porcelain can be sintered to make its bending strength reach 179Mpa by using sintered bauxite, clay and potash feldspar and albite as the main raw materials in oxidation atmosphere under the normal pressure. XRD, SEM and so on are utilized to study the relationships between factors like the composition of ingot, reduction particle size and heat insulating time at sintering temperature and the phase composition, microstructure and bending strength of ceramic body. The results show that the main phases in bauxite porcelain are corundum, mullite and glass, and the mullite is composed of two parts: primary mullite formed by clay conversion and secondary mullite whiskers precipitating from high temperature melt. The bending strength of ceramic body can be improved by enhancing the content of sintered bauxite in the formula: the smaller the particle size of the ceramic body is, the higher the bending strength will be. The high-temperature heat insulating technique is beneficial to the precipitation of certain quantitative secondary mullite whiskers so as to remarkably improve the strength of glass phase and ceramic body.展开更多
The present study experimentally investigated the effect of a simulated single-horn glaze ice accreted on ro- tor blades on the vortex structures in the wake of a hori- zontal axis wind turbine by using the stereoscop...The present study experimentally investigated the effect of a simulated single-horn glaze ice accreted on ro- tor blades on the vortex structures in the wake of a hori- zontal axis wind turbine by using the stereoscopic particle image velocimetry (Stereo-PIV) technique. During the ex- periments, four horizontal axis wind turbine models were tested, and both "free-run" and "phase-locked" Stereo-PIV measurements were carried out. Based on the "free-run" measurements, it was found that because of the simulated single-horn glaze ice, the shape, vorticity, and trajectory of tip vortices were changed significantly, and less kinetic en- ergy of the airflow could be harvested by the wind turbine. In addition, the "phase-locked" results indicated that the pres- ence of simulated single-horn glaze ice resulted in a dramatic reduction of the vorticity peak of the tip vortices. Moreover, as the length of the glaze ice increased, both root and tip vortex gaps were found to increase accordingly.展开更多
CO2 continuous wave laser beam had been applied to the laser glazing of plasma sprayed nanostructure zirconia thermal barrier coatings. The effects of laser glazing processing parameters on the surface figuration and ...CO2 continuous wave laser beam had been applied to the laser glazing of plasma sprayed nanostructure zirconia thermal barrier coatings. The effects of laser glazing processing parameters on the surface figuration and microstructure change had been carried out, the microstructure and phase composition of the coatings had been evaluated by the scanning electron microscope ( SEM) and the X-ray diffraction ( XRD ). SEM observation indicates that the microstructure of the as-glazed coating could be altered from singlecolumnar structure to a combination of the columnar grain and fine equiaxed grain with the different laser glazing conditions. XRD analysis illustrates that the predominance phase of the us-glazed coating is the metastable tetragonal phase, and the glazed coating with the single columnar structure has shown the clear orientation in (220) and (400) peaks while the other coatings do not show that.展开更多
Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection,resistance to heat and abrasion,high hardness,hygiene and ease of cleaning.The typical ...Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection,resistance to heat and abrasion,high hardness,hygiene and ease of cleaning.The typical process to produce enameled steels is roughly divided into two stages:the first stage consists of a forming process to give the desired shape to a steel substrate,and the second stage consists of a firing process to bond enamel frits on the substrate.This firing process requires a high temperature above 800 °C,which may lead to austenitic transformation and severe thermal deformation of the steel substrate.The aim of this study is to develop a finite element analysis (FE analysis) technique to predict the mechanical and thermal deformations of the enameled steels during forming and any further enameling process,including firing.The FE analysis involves analyzing the strain history of the steel substrate,which comprises the stress and thickness distributions of the substrate and its deformed shape,and the high-temperature behavior of the enamel coating layer.The validity of the FE analysis is verified through the U-bending test and firing test with various numbers and positions of enamel coating layers on the substrate.The results reveal that the FE analysis results agree well with the experimental results with 8% error.展开更多
Drying shrinkage of thermal insulation mortar with glazed hollow beads was measured by a vertical length comparator, and the influences of fly ash with different contents(0, 18%, 36%, and 54% were used) on the long-...Drying shrinkage of thermal insulation mortar with glazed hollow beads was measured by a vertical length comparator, and the influences of fly ash with different contents(0, 18%, 36%, and 54% were used) on the long-term drying shrinkage were discussed. The mass loss was measured by the weighting method and the pore structure was characterized using three different methods, including the light microscopy, the mercury intrusion porosimetry(MIP), and the nitrogen adsorption/desorption(NAD) experiments, and the correlations among them were researched. The results show that drying shrinkage process of thermal insulation mortar includes three steps with increasing curing time: the acceleration period(before 7 d), the deceleration period(7-365 d), and the metastable period(after 365 d). Drying shrinkage in the first stage(7 d before) increases quickly owing to the fast water loss, and its development in the last two stages is attributed to the increment of the pore volume of mortar with the radius below 50 nm, especially the increment of the pore volume fraction of the pore radius within the size range between 7.3 nm and 12.3 nm. There is no change in the drying shrinkage development trend of mortar with fly ash addition, and three steps in the service life, but fly ash addition in the mortar restrains its value. There is a linear relationship between the drying shrinkage and fly ash content, which means that drying shrinkage reduces with fly ash addition.展开更多
Infrared radiant powder was synthesized by conventional ceramic processing techniques by using Fe2 O3, MnO2, CuO, Co2 O3 and kaolin as raw materials. A novel infrared radant glaze was developed by introducing the infr...Infrared radiant powder was synthesized by conventional ceramic processing techniques by using Fe2 O3, MnO2, CuO, Co2 O3 and kaolin as raw materials. A novel infrared radant glaze was developed by introducing the infrared radiant powder into glazing as a functional additive. Infrared radiant characteristics of the powder and the glaze were investigated. The optimum content of infrared radiant powder in glazing was ascertained to be 5% . The infrared radiant glaze exhibits significant antibacterial and antifungal Junctions due to the thermal effect of infrared radiation. Antibacterial percentages of the glaze reach 91% - 100% when Escherichia coli, Staphylococcus aureus and Bacillus subtilis are used as model bacterium respectively, while antifungal percentage of the glaze exceeds 95% when Penicillum citrinum is used as model fungus.展开更多
A lead-free base glaze suitable for pearlescent pigments was prepared by a low-temperature solid-phase reaction with alkali waste.Tests were performed to evaluate the effects of the sintering conditions and alkali was...A lead-free base glaze suitable for pearlescent pigments was prepared by a low-temperature solid-phase reaction with alkali waste.Tests were performed to evaluate the effects of the sintering conditions and alkali waste composition on the prepared base glaze and pearlescent glaze.The experimental results show that partially replacing SiO_(2) with B_(2)O_(3) effectively reduced the sintering temperature and time to form a glass network,but the network structure becomes disconnected as the B_(2)O_(3) content increases.An amorphous base glaze was obtained when soda ash was replaced with a small amount of alkali waste,but increasing the addition of NaCl further was adverse to base glaze formation by resulting in crystallization of the base glaze and a decrease in the bridging oxygen content.The pearlescent pigment was thermally stable in the glaze at 750℃,while higher temperatures caused the crystalline phase of NaAlSiO_(4) to appear and adhere to the surface of pigment granules,which degraded the pearlescent effect of the glaze.展开更多
Objective : To evaluate the color change of the two-layer porcelain laminate veneer after adding veneering porcelain of different thickness to the 0. 2 mm thick aluminum oxide. Methods : Ten aluminum oxide disks were ...Objective : To evaluate the color change of the two-layer porcelain laminate veneer after adding veneering porcelain of different thickness to the 0. 2 mm thick aluminum oxide. Methods : Ten aluminum oxide disks were randomized into 2 groups. Each of five disks was veneered with Vita Lumin Shade 54 porcelain of thickness 0/0.4 mm and 0. 6 mm respectively. The L'a'b* color notations of the substrate covered with nan-veneered disks and 2 thickness porcelain veneered disks were measured separately and the color differences (AE) were calculated. Results ?Statistically significant differences in color coordinates of dark substrates were recorded after the substrate was covered by an aluminum oxide disk and also after the addition of veneering porcelain to the aluminum oxide disks in group 1 (P=0. 000 2) and group 2(P=0. 007 5) and between 2 groups (P=0. 000 1). Conclusion -The ability of masking underlying discoloration was increased and shifted to gray when the thickness of veneering porcelain increased.展开更多
The installed porcelain insulators on existing railway lines in China are prone to“snow flash”in winter.In order to prevent the occurrence of“snow flash”and improve the reliability of the insulators,a composite-po...The installed porcelain insulators on existing railway lines in China are prone to“snow flash”in winter.In order to prevent the occurrence of“snow flash”and improve the reliability of the insulators,a composite-porcelain insulator is designed.A multi-physics coupling simulation model is built based on numerical simulation methods of the electromagnetic field theory and computational fluid dynamics.Taking average electric field intensity on the surface of the insulator as the characteristic parameter of the electric field distortion degree and the snow crystal collision coefficient and distribution coefficient as the characteristic parameter of snow crystal deposition,the characteristics of snow crystal deposition under different wind speeds and wind direction angles and the electric field characteristics under two snow cover types are analyzed.The simulation results show that the average electric field intensity of composite-porcelain insulators is 10.4%and 13.8%,respectively,lower than that of porcelain insulators in vertical and horizontal wind snow covers,which can effectively reduce the degree of electric field distortion.The collision coefficient of snow crystals on the surface of the composite-porcelain insulator sheds is 16.0%higher than that of the porcelain insulator,and the collision coefficient of the trunk and the fittings are lower 20.2%and 11.9%than that of the porcelain insulator.There is almost no change in the distribution coefficient of the insulator sheds.展开更多
Porcelain aorta(PA)is an asymptomatic atherosclerotic disease,characterized by circumferential calcification throughout the whole perimeter of the aorta.It is seen in 2%to 9.3%of patients undergoing elective coronary ...Porcelain aorta(PA)is an asymptomatic atherosclerotic disease,characterized by circumferential calcification throughout the whole perimeter of the aorta.It is seen in 2%to 9.3%of patients undergoing elective coronary artery bypass grafting(CABG)and makes manipulation of the ascending aorta impossible.It has been clearly shown that most emboli seen and detected during the CABG procedure occur during aortic cross-clamping and aortic side-clamping.Manipulation of porcelain or a severely atherosclerotic aorta increases the risk of perioperative stroke.The incidence of stroke after CABG is between 0.48%and 2.9%,and the risk is correlated with the extent and severity of the atherosclerotic disease.A conventional CABG procedure involves successive steps that include cannulation of the ascending aorta,application of a cross-clamp to the aorta,and partial clamping of the aorta to create the proximal anastomosis.Therefore in procedures that involve cannulation,clamping,or proximal anastomosis,and where aortic manipulation is inevitable,preassessment of the atherosclerotic aortic plaques is crucial.Although many surgeons still rely on intraoperative manual aortic palpation,this approach has very low sensitivity and underestimates the severity of the atherosclerotic illness.Imaging methods including preoperative computed tomography or intraoperative epiaortic ultrasonography enable modification of the surgical technique according to the severity of atherosclerosis.Various surgical techniques have been described to reduce the risk of atheroembolism that may lead to cerebrovascular events in patients with severely atherosclerotic ascending aorta.Anaortic or“no-touch”techniques that do not utilize aortic manipulation may significantly decrease the development of neurological complications by avoiding aortic maneuvers known to cause emboli.In cases where severe atherosclerotic disease or other factors preclude safe use of the ascending aorta,modifications in the surgical techniques,such as switching to different cannulation sites including the axillary/subclavian,femoral and innominate arteries,or using hypothermic ventricular fibrillation and in-situ pedicled arterial grafts,or performing proximal anastomoses at alternative anatomical locations will enable CABG operations to be performed safely with low morbidity and mortality rates in patients with porcelain aortas.展开更多
梳理纪录片Treasures of Chinese Porcelain的拍摄背景、内容及重要观点,进行图像学与意识形态分析,对片中多次出现的维多利亚和阿尔伯特博物馆陶瓷、《陶冶图》、蓝白色画面、生产污染等镜头进行探讨。该片具有较浓厚的"欧洲中心...梳理纪录片Treasures of Chinese Porcelain的拍摄背景、内容及重要观点,进行图像学与意识形态分析,对片中多次出现的维多利亚和阿尔伯特博物馆陶瓷、《陶冶图》、蓝白色画面、生产污染等镜头进行探讨。该片具有较浓厚的"欧洲中心主义"意识形态色彩,对其叙述产生了较大影响。纪录片的拍摄应体现对真实世界与历史的了解,而中外文化的交流更应建立在充分沟通、认同的基础之上。展开更多
基金supported by Natural Science Foundation of China(Nos.51762027 and 11875312)Jiangxi Collaborative Innovation Center of Ceramic Relics Conservation and Imperial Kiln Research
文摘A shard of Chinese underglaze copper-red porcelain from the Yuan dynasty (AD 1271–1368) made in the Jingdezhen kiln was measured by synchrotron radiation- induced X-ray fluorescence mapping and X-ray absorption near-edge spectroscopy to investigate the influence of copper element distribution and speciation on the color of porcelain. In black-colored region, copper accumulates at the interface between the body and glaze layers with metallic copper particles as the main speciation. In contrast, Cu is irregularly distributed in the red-colored region with multi-valence speciation. The differences in Cu distribution and speciation in black- and red-colored regions indicate that they are the main factors influencing the different colors of copper-red underglaze porcelain.
文摘In China, the firing and glazed red techniques of producing underglaze-red porcelain began early in the Yuan Dynasty (AD1206~ 1368). This paper reports the results of the PIXE analysis of ancient Chinese underglaze-red porcelain produced at Kuan kiln (Jingdezhen, Jiangxi Province) in the Yuan Dynasty. In this work the elemental composition analysis of the obtained samples was carried out using the PIXE facility of a 3 MeV tandem accelerator at Fudan University. The major; minor and trace elements of the clay body, white and red glazes were determined,and details of the results are presented. The obtained data can be used for identification of precious Chinese Yuan underglaze-red porcelain.
基金Funded by the National Natural Science Foundation of China(No.52202231)the College Students Innovation and Entrepreneurship Training Program of Hubei University of Technology(No.202310500039)。
文摘A copper-red and silver-white metallic glaze of R_(2)O-RO-Al_(2)O_(3)-SiO_(2)-P_(2)O_(5)system was synthesized by adjusting the firing temperature and glaze components.The coloration mechanism of the metallic glaze was revealed via investigation of the microstructure of the glaze.Our research reveals that the metallic glaze with different colors is mainly due to the amount of Fe_(2)O_(3).The metallic glaze shows a silver-white luster due to a structural color ofα-Fe_(2)O_(3)crystals with a good orientation when the sample contains 0.0939 mol of Fe_(2)O_(3),maintaining temperatures at 1150℃for 0.5 h.The metallic glaze is copper-red which is dominated by the coupling of chemical and structural color ofα-Fe_(2)O_(3)crystals when the sample contains 0.0783 mol of Fe_(2)O_(3).After testing the amount of SiO_(2),we find that 4.0499 mol is the optimal amount to form the ceramic network,and 0.27 mol AlPO_(4)is the best amount to promote phase separation.
基金Scientific Research Fund of IEM,CEA under Grant Nos.2016B09,2014B12China Natural Science Foundation under Grant Nos.51478442,51408565
文摘Porcelain electrical equipment (PEE), such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers (MTMD). An MTMD damping device involving three mass units, named a triple tuned mass damper (TTMD), is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.
基金Funded by the Natural Science Foundation of Shaanxi Province(No.2003E225)
文摘The characteristics of broken surfaces were r esearched by a scanning electron microscope (SEM) and a reflection microscope, a nd the fractal dimensions of broken surfaces were measured by the Slit Island me thod. The experimental results indicate that the broken surface of aluminum elec tric porcelain is a fractal body in statistics, and the fractal dimensions of br oken surfaces are different with the different amplification multiple value.In a ll of measured fractal dimensions,both of values measured in 100× under reflect ion microscope and in 500× under SEM are maximum, whereas the values measur ed in 63× under reflection microscope and in 2000× under SEM are obviously min imum. The fractal dimensions of broken surfaces are also affected by the degrees of gray comparison and the kinds of measuring methods. The relationships betwee n the fractal dimensions of broken surfaces and porcelain bend strengths are tha t they are in positive correlation on the low multiples and in negative correlat ion on the high multiples.
基金This research was funded by the National High Technology Research and Development Program of China(Grant No.2002AA302204)Science and Technology Program of Guangdong Provrince of China(Grant No.2001A1070102).
文摘Usually the thermal expansion coefficients (TEC) of metals are higher than that of porcelains. In order to match the TECs in the case of coating porcelains on metals, high TEC porcelains are needed. In this research, the high TEC phase leucite (KAlSi2 O6) in the high TEC porcelain was prepared by sol-gel method. The crystal size of leucite made by sol-gel is about 77nm through controlling the process parameters. The process from xerogel to leucite was investigated by means of DSC (differential scanning calorimetry), TG (thermogravimetry), XRD ( X-ray diffraction) and IR (infrared absorption spectrum). Leucite had been detected after the gel was treated at 900℃, this formation temperature is about 250℃ lower than that of melting method. The porcelain made from 50% of the leucite powder and 50% of low fused temperature frit has an average TEC of 19.2×10-6/℃ C from room temperature to 450℃, which is much higher than the common porcelains.
基金Supported by the Industrial Foster of the Education Department of Shaanxi Province (No. 3JC11)
文摘Bauxite porcelain can be sintered to make its bending strength reach 179Mpa by using sintered bauxite, clay and potash feldspar and albite as the main raw materials in oxidation atmosphere under the normal pressure. XRD, SEM and so on are utilized to study the relationships between factors like the composition of ingot, reduction particle size and heat insulating time at sintering temperature and the phase composition, microstructure and bending strength of ceramic body. The results show that the main phases in bauxite porcelain are corundum, mullite and glass, and the mullite is composed of two parts: primary mullite formed by clay conversion and secondary mullite whiskers precipitating from high temperature melt. The bending strength of ceramic body can be improved by enhancing the content of sintered bauxite in the formula: the smaller the particle size of the ceramic body is, the higher the bending strength will be. The high-temperature heat insulating technique is beneficial to the precipitation of certain quantitative secondary mullite whiskers so as to remarkably improve the strength of glass phase and ceramic body.
基金supported by Science and Technology Commission of Shanghai Municipality(15ZR1442700)
文摘The present study experimentally investigated the effect of a simulated single-horn glaze ice accreted on ro- tor blades on the vortex structures in the wake of a hori- zontal axis wind turbine by using the stereoscopic particle image velocimetry (Stereo-PIV) technique. During the ex- periments, four horizontal axis wind turbine models were tested, and both "free-run" and "phase-locked" Stereo-PIV measurements were carried out. Based on the "free-run" measurements, it was found that because of the simulated single-horn glaze ice, the shape, vorticity, and trajectory of tip vortices were changed significantly, and less kinetic en- ergy of the airflow could be harvested by the wind turbine. In addition, the "phase-locked" results indicated that the pres- ence of simulated single-horn glaze ice resulted in a dramatic reduction of the vorticity peak of the tip vortices. Moreover, as the length of the glaze ice increased, both root and tip vortex gaps were found to increase accordingly.
文摘CO2 continuous wave laser beam had been applied to the laser glazing of plasma sprayed nanostructure zirconia thermal barrier coatings. The effects of laser glazing processing parameters on the surface figuration and microstructure change had been carried out, the microstructure and phase composition of the coatings had been evaluated by the scanning electron microscope ( SEM) and the X-ray diffraction ( XRD ). SEM observation indicates that the microstructure of the as-glazed coating could be altered from singlecolumnar structure to a combination of the columnar grain and fine equiaxed grain with the different laser glazing conditions. XRD analysis illustrates that the predominance phase of the us-glazed coating is the metastable tetragonal phase, and the glazed coating with the single columnar structure has shown the clear orientation in (220) and (400) peaks while the other coatings do not show that.
基金Project(NRF-2012R1A5A1048294)supported by the National Research Foundation of Korea(NRF)Grant funded by the Ministry of Education,Science and Technologythe LG Electronics
文摘Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection,resistance to heat and abrasion,high hardness,hygiene and ease of cleaning.The typical process to produce enameled steels is roughly divided into two stages:the first stage consists of a forming process to give the desired shape to a steel substrate,and the second stage consists of a firing process to bond enamel frits on the substrate.This firing process requires a high temperature above 800 °C,which may lead to austenitic transformation and severe thermal deformation of the steel substrate.The aim of this study is to develop a finite element analysis (FE analysis) technique to predict the mechanical and thermal deformations of the enameled steels during forming and any further enameling process,including firing.The FE analysis involves analyzing the strain history of the steel substrate,which comprises the stress and thickness distributions of the substrate and its deformed shape,and the high-temperature behavior of the enamel coating layer.The validity of the FE analysis is verified through the U-bending test and firing test with various numbers and positions of enamel coating layers on the substrate.The results reveal that the FE analysis results agree well with the experimental results with 8% error.
基金Funded by the National Key Technology R&D Program of China during the 12th Five-year Plan(No.2012BAJ20B02)
文摘Drying shrinkage of thermal insulation mortar with glazed hollow beads was measured by a vertical length comparator, and the influences of fly ash with different contents(0, 18%, 36%, and 54% were used) on the long-term drying shrinkage were discussed. The mass loss was measured by the weighting method and the pore structure was characterized using three different methods, including the light microscopy, the mercury intrusion porosimetry(MIP), and the nitrogen adsorption/desorption(NAD) experiments, and the correlations among them were researched. The results show that drying shrinkage process of thermal insulation mortar includes three steps with increasing curing time: the acceleration period(before 7 d), the deceleration period(7-365 d), and the metastable period(after 365 d). Drying shrinkage in the first stage(7 d before) increases quickly owing to the fast water loss, and its development in the last two stages is attributed to the increment of the pore volume of mortar with the radius below 50 nm, especially the increment of the pore volume fraction of the pore radius within the size range between 7.3 nm and 12.3 nm. There is no change in the drying shrinkage development trend of mortar with fly ash addition, and three steps in the service life, but fly ash addition in the mortar restrains its value. There is a linear relationship between the drying shrinkage and fly ash content, which means that drying shrinkage reduces with fly ash addition.
基金Funded by the Foundation for Excellent Youth of Wuhan (No. 995004088G) and key Project of New Products of Hubei Province
文摘Infrared radiant powder was synthesized by conventional ceramic processing techniques by using Fe2 O3, MnO2, CuO, Co2 O3 and kaolin as raw materials. A novel infrared radant glaze was developed by introducing the infrared radiant powder into glazing as a functional additive. Infrared radiant characteristics of the powder and the glaze were investigated. The optimum content of infrared radiant powder in glazing was ascertained to be 5% . The infrared radiant glaze exhibits significant antibacterial and antifungal Junctions due to the thermal effect of infrared radiation. Antibacterial percentages of the glaze reach 91% - 100% when Escherichia coli, Staphylococcus aureus and Bacillus subtilis are used as model bacterium respectively, while antifungal percentage of the glaze exceeds 95% when Penicillum citrinum is used as model fungus.
基金by the National Natural Science Foundation of China(No.51402097)the College Students Innovation and Entrepreneurship Training Program of Hubei University of Technology(No.202010500045)。
文摘A lead-free base glaze suitable for pearlescent pigments was prepared by a low-temperature solid-phase reaction with alkali waste.Tests were performed to evaluate the effects of the sintering conditions and alkali waste composition on the prepared base glaze and pearlescent glaze.The experimental results show that partially replacing SiO_(2) with B_(2)O_(3) effectively reduced the sintering temperature and time to form a glass network,but the network structure becomes disconnected as the B_(2)O_(3) content increases.An amorphous base glaze was obtained when soda ash was replaced with a small amount of alkali waste,but increasing the addition of NaCl further was adverse to base glaze formation by resulting in crystallization of the base glaze and a decrease in the bridging oxygen content.The pearlescent pigment was thermally stable in the glaze at 750℃,while higher temperatures caused the crystalline phase of NaAlSiO_(4) to appear and adhere to the surface of pigment granules,which degraded the pearlescent effect of the glaze.
文摘Objective : To evaluate the color change of the two-layer porcelain laminate veneer after adding veneering porcelain of different thickness to the 0. 2 mm thick aluminum oxide. Methods : Ten aluminum oxide disks were randomized into 2 groups. Each of five disks was veneered with Vita Lumin Shade 54 porcelain of thickness 0/0.4 mm and 0. 6 mm respectively. The L'a'b* color notations of the substrate covered with nan-veneered disks and 2 thickness porcelain veneered disks were measured separately and the color differences (AE) were calculated. Results ?Statistically significant differences in color coordinates of dark substrates were recorded after the substrate was covered by an aluminum oxide disk and also after the addition of veneering porcelain to the aluminum oxide disks in group 1 (P=0. 000 2) and group 2(P=0. 007 5) and between 2 groups (P=0. 000 1). Conclusion -The ability of masking underlying discoloration was increased and shifted to gray when the thickness of veneering porcelain increased.
基金National Natural Science Foundation of China(No.51867013)。
文摘The installed porcelain insulators on existing railway lines in China are prone to“snow flash”in winter.In order to prevent the occurrence of“snow flash”and improve the reliability of the insulators,a composite-porcelain insulator is designed.A multi-physics coupling simulation model is built based on numerical simulation methods of the electromagnetic field theory and computational fluid dynamics.Taking average electric field intensity on the surface of the insulator as the characteristic parameter of the electric field distortion degree and the snow crystal collision coefficient and distribution coefficient as the characteristic parameter of snow crystal deposition,the characteristics of snow crystal deposition under different wind speeds and wind direction angles and the electric field characteristics under two snow cover types are analyzed.The simulation results show that the average electric field intensity of composite-porcelain insulators is 10.4%and 13.8%,respectively,lower than that of porcelain insulators in vertical and horizontal wind snow covers,which can effectively reduce the degree of electric field distortion.The collision coefficient of snow crystals on the surface of the composite-porcelain insulator sheds is 16.0%higher than that of the porcelain insulator,and the collision coefficient of the trunk and the fittings are lower 20.2%and 11.9%than that of the porcelain insulator.There is almost no change in the distribution coefficient of the insulator sheds.
文摘Porcelain aorta(PA)is an asymptomatic atherosclerotic disease,characterized by circumferential calcification throughout the whole perimeter of the aorta.It is seen in 2%to 9.3%of patients undergoing elective coronary artery bypass grafting(CABG)and makes manipulation of the ascending aorta impossible.It has been clearly shown that most emboli seen and detected during the CABG procedure occur during aortic cross-clamping and aortic side-clamping.Manipulation of porcelain or a severely atherosclerotic aorta increases the risk of perioperative stroke.The incidence of stroke after CABG is between 0.48%and 2.9%,and the risk is correlated with the extent and severity of the atherosclerotic disease.A conventional CABG procedure involves successive steps that include cannulation of the ascending aorta,application of a cross-clamp to the aorta,and partial clamping of the aorta to create the proximal anastomosis.Therefore in procedures that involve cannulation,clamping,or proximal anastomosis,and where aortic manipulation is inevitable,preassessment of the atherosclerotic aortic plaques is crucial.Although many surgeons still rely on intraoperative manual aortic palpation,this approach has very low sensitivity and underestimates the severity of the atherosclerotic illness.Imaging methods including preoperative computed tomography or intraoperative epiaortic ultrasonography enable modification of the surgical technique according to the severity of atherosclerosis.Various surgical techniques have been described to reduce the risk of atheroembolism that may lead to cerebrovascular events in patients with severely atherosclerotic ascending aorta.Anaortic or“no-touch”techniques that do not utilize aortic manipulation may significantly decrease the development of neurological complications by avoiding aortic maneuvers known to cause emboli.In cases where severe atherosclerotic disease or other factors preclude safe use of the ascending aorta,modifications in the surgical techniques,such as switching to different cannulation sites including the axillary/subclavian,femoral and innominate arteries,or using hypothermic ventricular fibrillation and in-situ pedicled arterial grafts,or performing proximal anastomoses at alternative anatomical locations will enable CABG operations to be performed safely with low morbidity and mortality rates in patients with porcelain aortas.
文摘梳理纪录片Treasures of Chinese Porcelain的拍摄背景、内容及重要观点,进行图像学与意识形态分析,对片中多次出现的维多利亚和阿尔伯特博物馆陶瓷、《陶冶图》、蓝白色画面、生产污染等镜头进行探讨。该片具有较浓厚的"欧洲中心主义"意识形态色彩,对其叙述产生了较大影响。纪录片的拍摄应体现对真实世界与历史的了解,而中外文化的交流更应建立在充分沟通、认同的基础之上。