RENEWING THE FORBIDDEN CITY’S CENTURY-OLD LEGACY.Oriental Outlook.27 November 2025.At sunrise,the Forbidden City glows under a veil of gold;at night,it retreats into quiet dignity.But the palace never really sleeps.A...RENEWING THE FORBIDDEN CITY’S CENTURY-OLD LEGACY.Oriental Outlook.27 November 2025.At sunrise,the Forbidden City glows under a veil of gold;at night,it retreats into quiet dignity.But the palace never really sleeps.As visitors depart,the“digital relic vault”awakens online,where porcelain,calligraphy,jade and timepieces reveal their beauty in virtual form.History continues to breathe in the data stream.展开更多
This article focuses on the connection between Leibniz and the production of Saxony hard porcelain.Leibniz commissioned Jesuits to investigate China’s porcelain-making techniques,sharing relevant information with Zin...This article focuses on the connection between Leibniz and the production of Saxony hard porcelain.Leibniz commissioned Jesuits to investigate China’s porcelain-making techniques,sharing relevant information with Zinnhaus and inspiring him with scientific ideas.Zinnhaus achieved key technological breakthroughs,and Poterger continued to refine the formula and establish the factory.Although Leibniz did not directly participate in the experiments,he promoted this process through his ideas,information,and connections,serving as an important behind-the-scenes force.展开更多
In the early 18th century,to meet Europe's urgent demand for Jingdezhen's ceramic production techniques,French Jesuit missionary François Xavier d'Entrecolles traveled to Jingdezhen,Jiangxi.While cond...In the early 18th century,to meet Europe's urgent demand for Jingdezhen's ceramic production techniques,French Jesuit missionary François Xavier d'Entrecolles traveled to Jingdezhen,Jiangxi.While conducting missionary work,he thoroughly investigated local porcelain-making techniques.He compiled his findings into two lengthy letters and sent samples of porcelain raw materials to Europe,successfully disseminating Jingdezhen's ceramic artistry to the continent.D'Entrecolles skillfully integrated the protective function of his religious identity,the resource coordination capabilities of political networks,the documentation methods of empirical science,and a localized infiltration strategy,constructing a four-dimensional investigative framework of"missionary integration-observation and interviews-literature review-experimental verification"through Broussonetia papyrifera.These systematic research methods enabled him to comprehensively master Jingdezhen's porcelain technology at the time,establishing him as the pioneer of Western systematic studies on Chinese ceramics and creating a new paradigm of"field research+scientific empiricism"in early cross-cultural technological transmission.展开更多
1 Fascinated by the beauty of white Chinese porcelain(瓷),Marc Leuthold has spent two months creating contemporary artworks using the local clay and firing methods of Quyang,a county in Hebei Province,with over a thou...1 Fascinated by the beauty of white Chinese porcelain(瓷),Marc Leuthold has spent two months creating contemporary artworks using the local clay and firing methods of Quyang,a county in Hebei Province,with over a thousand years of ceramic⁃making history.2 Leuthold,an elected lifetime member of the International Academy of Ceramics and a retired professor from the State University of New York,has been invited to around 20 Chinese cities to exhibit,lecture and exchange ideas.He also worked full⁃time at an art institute in Shanghai from 2018 to 2023.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
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
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
Porcelain cap and pin insulators are by far the most popular suspension insulators in high voltage(HV) distribution networks all around the world.Inspection and condition monitoring of HV insulators is also very impor...Porcelain cap and pin insulators are by far the most popular suspension insulators in high voltage(HV) distribution networks all around the world.Inspection and condition monitoring of HV insulators is also very important to the utility companies because of the critical and vital role that they play in distribution systems.In terms of safety, practicality and ease of use,remote detection methods are more popular among the line technicians.A new remote condition assessment method based on electromagnetic radiations from porcelain insulators is presented in this paper. In a lab environment,a string of two porcelain insulators is energized by a 45 kV transformer.Electromagnetic radiations due to the partial discharge activities inside the porcelain insulator are captured by passive sensors and antennas. Two cases of defective insulators on a two insulator string are studied here.The first case focuses on the effect of contaminated porcelain shells on radiation signature of partial discharges.A polluted porcelain shell with ESDD level of 0.03 mg/cm^2 was first tested.The second case studies the effect of cracks of an intentionally-cracked porcelain shell. The cracked insulator is also tested on a two insulator string.To compare the partial discharge radiation signature of different faulty insulators,phase resolved graphs were developed.The electromagnetic radiated signature of a polluted insulator and a cracked insulator was calculated and compared using phase resolved graphs.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
In recent years,more than 50%of the cities in the inland area of our country have suffered from moderate pollution.It can affect the distribution of electric field along the surface of insulator and the pollution char...In recent years,more than 50%of the cities in the inland area of our country have suffered from moderate pollution.It can affect the distribution of electric field along the surface of insulator and the pollution characteristics of its surface area,even endanger the safe operation of transmission lines.This paper takes the XSP-160 porcelain three umbrella insulator under the action of 0–±30 kV DC voltage as the research object,and establishes the physical model of the insulator;uses COMSOL software to simulate the electric field of the insulator.The comparison with the results of the wind tunnel test of North China Electric Power University verifies the rationality of the simulation method.In view of the medium pollution environment which often occurs in the inland area,the force of the polluted particles deposited on the insulator under 110 kV DC voltage was analyzed.The distribution characteristics of the electric field along the surface in the clean and three kinds of pollution environment(light,medium and heavy)were simulated and compared.The results showed that:1)In the moderate pollution environment,the influence of fluid drag force on the movement of polluted particles is greater at the initial stage(0.28–0.33 s);at the late stage(after 0.33 s),the influence of the electric field force begins to increase,and gradually plays a major role in the process of fouling.2)In the three different polluted environments,the potential along the surface of each umbrella skirt of the insulator increases non-linearly with the increasing of the pollution concentration,and there are apparent potential inflection points near b and l.3)The pollution particle concentration has the most obvious influence on the electric field along the low-voltage umbrella skirt,whose potential distortion rate can be up to 220 times in the heavy polluted environment.展开更多
The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens w...The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups（n515）. Fifteen specimens（group 1） were glazed and 15 specimens（group 2） were veneered with feldspathic ceramic and then glazed. Prior to grinding,maximum roughness depth（Rmax） values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 mm, 10 mm, and 7.5 mm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmaxvalues were determined. Differences between groups were examined using one-way analysis of variance（ANOVA）. The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing.It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing; more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.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
文摘RENEWING THE FORBIDDEN CITY’S CENTURY-OLD LEGACY.Oriental Outlook.27 November 2025.At sunrise,the Forbidden City glows under a veil of gold;at night,it retreats into quiet dignity.But the palace never really sleeps.As visitors depart,the“digital relic vault”awakens online,where porcelain,calligraphy,jade and timepieces reveal their beauty in virtual form.History continues to breathe in the data stream.
文摘This article focuses on the connection between Leibniz and the production of Saxony hard porcelain.Leibniz commissioned Jesuits to investigate China’s porcelain-making techniques,sharing relevant information with Zinnhaus and inspiring him with scientific ideas.Zinnhaus achieved key technological breakthroughs,and Poterger continued to refine the formula and establish the factory.Although Leibniz did not directly participate in the experiments,he promoted this process through his ideas,information,and connections,serving as an important behind-the-scenes force.
文摘In the early 18th century,to meet Europe's urgent demand for Jingdezhen's ceramic production techniques,French Jesuit missionary François Xavier d'Entrecolles traveled to Jingdezhen,Jiangxi.While conducting missionary work,he thoroughly investigated local porcelain-making techniques.He compiled his findings into two lengthy letters and sent samples of porcelain raw materials to Europe,successfully disseminating Jingdezhen's ceramic artistry to the continent.D'Entrecolles skillfully integrated the protective function of his religious identity,the resource coordination capabilities of political networks,the documentation methods of empirical science,and a localized infiltration strategy,constructing a four-dimensional investigative framework of"missionary integration-observation and interviews-literature review-experimental verification"through Broussonetia papyrifera.These systematic research methods enabled him to comprehensively master Jingdezhen's porcelain technology at the time,establishing him as the pioneer of Western systematic studies on Chinese ceramics and creating a new paradigm of"field research+scientific empiricism"in early cross-cultural technological transmission.
文摘1 Fascinated by the beauty of white Chinese porcelain(瓷),Marc Leuthold has spent two months creating contemporary artworks using the local clay and firing methods of Quyang,a county in Hebei Province,with over a thousand years of ceramic⁃making history.2 Leuthold,an elected lifetime member of the International Academy of Ceramics and a retired professor from the State University of New York,has been invited to around 20 Chinese cities to exhibit,lecture and exchange ideas.He also worked full⁃time at an art institute in Shanghai from 2018 to 2023.
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 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.
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.
文摘Porcelain cap and pin insulators are by far the most popular suspension insulators in high voltage(HV) distribution networks all around the world.Inspection and condition monitoring of HV insulators is also very important to the utility companies because of the critical and vital role that they play in distribution systems.In terms of safety, practicality and ease of use,remote detection methods are more popular among the line technicians.A new remote condition assessment method based on electromagnetic radiations from porcelain insulators is presented in this paper. In a lab environment,a string of two porcelain insulators is energized by a 45 kV transformer.Electromagnetic radiations due to the partial discharge activities inside the porcelain insulator are captured by passive sensors and antennas. Two cases of defective insulators on a two insulator string are studied here.The first case focuses on the effect of contaminated porcelain shells on radiation signature of partial discharges.A polluted porcelain shell with ESDD level of 0.03 mg/cm^2 was first tested.The second case studies the effect of cracks of an intentionally-cracked porcelain shell. The cracked insulator is also tested on a two insulator string.To compare the partial discharge radiation signature of different faulty insulators,phase resolved graphs were developed.The electromagnetic radiated signature of a polluted insulator and a cracked insulator was calculated and compared using phase resolved graphs.
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.
基金Science and Technology Project of State Grid Corporation(GY7111053)[www.sgcc.com.cn].
文摘In recent years,more than 50%of the cities in the inland area of our country have suffered from moderate pollution.It can affect the distribution of electric field along the surface of insulator and the pollution characteristics of its surface area,even endanger the safe operation of transmission lines.This paper takes the XSP-160 porcelain three umbrella insulator under the action of 0–±30 kV DC voltage as the research object,and establishes the physical model of the insulator;uses COMSOL software to simulate the electric field of the insulator.The comparison with the results of the wind tunnel test of North China Electric Power University verifies the rationality of the simulation method.In view of the medium pollution environment which often occurs in the inland area,the force of the polluted particles deposited on the insulator under 110 kV DC voltage was analyzed.The distribution characteristics of the electric field along the surface in the clean and three kinds of pollution environment(light,medium and heavy)were simulated and compared.The results showed that:1)In the moderate pollution environment,the influence of fluid drag force on the movement of polluted particles is greater at the initial stage(0.28–0.33 s);at the late stage(after 0.33 s),the influence of the electric field force begins to increase,and gradually plays a major role in the process of fouling.2)In the three different polluted environments,the potential along the surface of each umbrella skirt of the insulator increases non-linearly with the increasing of the pollution concentration,and there are apparent potential inflection points near b and l.3)The pollution particle concentration has the most obvious influence on the electric field along the low-voltage umbrella skirt,whose potential distortion rate can be up to 220 times in the heavy polluted environment.
基金Forschungsgemeinschaft Dental e.V. for supporting this study (project no. 3/2012)
文摘The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups（n515）. Fifteen specimens（group 1） were glazed and 15 specimens（group 2） were veneered with feldspathic ceramic and then glazed. Prior to grinding,maximum roughness depth（Rmax） values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 mm, 10 mm, and 7.5 mm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmaxvalues were determined. Differences between groups were examined using one-way analysis of variance（ANOVA）. The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing.It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing; more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.
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.
