The parameters of beam transverse positions at HLS 200 MeV LINAC are very important to injection ef-ficiency. We have designed a new non-interceptive strip line beam position monitor (BPM) as a substitution for the or...The parameters of beam transverse positions at HLS 200 MeV LINAC are very important to injection ef-ficiency. We have designed a new non-interceptive strip line beam position monitor (BPM) as a substitution for the original interceptive fluorescent target. This paper gives out the theoretical analysis and bench test result of the strip line BPM. The BPM has a characteristic impedance of (50±5)?, a reflection coefficient of less than –4 dB, a band-width of 400 MHz, a coupling coefficient of less than -15 dB, and a sensitivity of 1.16 dB/mm. Additionally, the strip line BPM has a good linearity.展开更多
It has been observed that H^- current could be improved by adding Ar to H2 plasma. But due to a slower pumping speed for Ar with the existing pumping scheme, the tank pressure will increase quickly during the length o...It has been observed that H^- current could be improved by adding Ar to H2 plasma. But due to a slower pumping speed for Ar with the existing pumping scheme, the tank pressure will increase quickly during the length of a beam pulse. Since H^- stripping loss depends on the tank pressure and gas species, part of the H^- beam can be converted to H^0 and then H^0 can be converted into H^＋ with background H2 and Ar gas thickness. Therefore, the H^- beam current, measured by a Faraday cup, situated at a distance L from GG （ground grid）, will decrease because it will be converted into a H^＋ current. This gives a ratio of the Faraday cup net current to the H^- beam current before stripping at background partial pressure of Ar.展开更多
The influence of oxide scales on the corrosion behaviors of B510 L hot-rolled steel strips was investigated in this study. Focused ion beams and scanning electron microscopy were used to observe the morphologies of ox...The influence of oxide scales on the corrosion behaviors of B510 L hot-rolled steel strips was investigated in this study. Focused ion beams and scanning electron microscopy were used to observe the morphologies of oxide scales on the surface and cross sections of the hot-rolled steel. Raman spectroscopy and X-ray diffraction were used for the phase analysis of the oxide scales and corrosion products. The corrosion potential and impedance were measured by anodic polarization and electrochemical impedance spectroscopy. According to the results, oxide scales on the hot-rolled strips mainly comprise iron and iron oxides. The correlation between mass gain and test time follows a power exponential rule in the damp-heat test. The corrosion products are found to be mainly composed of γ-Fe OOH, Fe3O4, ？-Fe OOH, and γ-Fe2O3. The contents of the corrosion products are different on the surfaces of the steels with and without oxide scales. The steel with oxide scales is found to show a higher corrosion resistance and lower corrosion rate.展开更多
An analytical method was proposed to solve the mechanical problems of stamping a thin strip on an elastic foundation. The thin strip was divided into four parts according to its deformation and contact with the punch ...An analytical method was proposed to solve the mechanical problems of stamping a thin strip on an elastic foundation. The thin strip was divided into four parts according to its deformation and contact with the punch and the elastic foundation, especially an elastic-plastic part was considered in the deflection of the thin strip. Analytical solutions were derived individually for each part and two models were established with the help of elastic and plastic large deflection theories. Compatibility conditions between the neighboring parts of the thin strip constructed the non-linear equation group. Solutions were carried out by programming with a software. The deformation shape, the membrane force, and the moment and shear force of the deformed thin strip were obtained. The results of the two models were compared. The study shows that the method is effective.展开更多
Vapor deposited coatings onto strip steel are a promising alternative as functional layers for corrosion protection or high abrasion resistance.Conventional coating systems have some limits regarding environmental com...Vapor deposited coatings onto strip steel are a promising alternative as functional layers for corrosion protection or high abrasion resistance.Conventional coating systems have some limits regarding environmental compatibility,the range of coating materials and application properties. Physical vapor deposition(PVD) is an environment-friendly technology and enables nearly unlimited material and process variety.Electron beam high-rate evaporation with deposition rates up to some micrometers per second is the most productive PVD technology for low cost coating.The combination of evaporation with powerful plasma is an efficient way to improve the layer properties.The developed plasma sources can be used for special plasma enhanced chemical vapor deposition(PECVD) processes too. The paper gives an overview about the latest developments in these technologies.Furthermore,the paper explains some examples of new layer stacks onto steel strips.While enhanced corrosion protection can be obtained by magnesium,aluminium or copper containing coatings other functional surface properties come more and more in the focus of interest.For instance,decorative gold colored layers,transparent scratch resistant layers,hard coatings and photo catalytic layers were deposited on running steel strips.Functional layers and layer systems for energy saving and sun energy absorption by solar thermal effects and photo voltaics are under development.The coatings are prepared under the conditions of very high deposition rates using our in-line vacuum coater for metallic strips and sheets with the name MAXI.The influence of the process and plasma parameters on the layer properties were investigated and will be demonstrated for some applications.展开更多
基金Supported by Project of Building a High-level University Well-known Both in China and in the World (KY2901), and Project of Hi-tech Research and Development Program of China (863-410-8-2)
文摘The parameters of beam transverse positions at HLS 200 MeV LINAC are very important to injection ef-ficiency. We have designed a new non-interceptive strip line beam position monitor (BPM) as a substitution for the original interceptive fluorescent target. This paper gives out the theoretical analysis and bench test result of the strip line BPM. The BPM has a characteristic impedance of (50±5)?, a reflection coefficient of less than –4 dB, a band-width of 400 MHz, a coupling coefficient of less than -15 dB, and a sensitivity of 1.16 dB/mm. Additionally, the strip line BPM has a good linearity.
文摘It has been observed that H^- current could be improved by adding Ar to H2 plasma. But due to a slower pumping speed for Ar with the existing pumping scheme, the tank pressure will increase quickly during the length of a beam pulse. Since H^- stripping loss depends on the tank pressure and gas species, part of the H^- beam can be converted to H^0 and then H^0 can be converted into H^＋ with background H2 and Ar gas thickness. Therefore, the H^- beam current, measured by a Faraday cup, situated at a distance L from GG （ground grid）, will decrease because it will be converted into a H^＋ current. This gives a ratio of the Faraday cup net current to the H^- beam current before stripping at background partial pressure of Ar.
基金supported by the National Natural Science Foundation of China(No.51222106)the Fundamental Research Funds for the Central Universities(No.FRF-TP-14-011C1)+1 种基金the Major State Basic Research Development Program of China(No.2014CB643300)the Beijing Municipal Commission of Education
文摘The influence of oxide scales on the corrosion behaviors of B510 L hot-rolled steel strips was investigated in this study. Focused ion beams and scanning electron microscopy were used to observe the morphologies of oxide scales on the surface and cross sections of the hot-rolled steel. Raman spectroscopy and X-ray diffraction were used for the phase analysis of the oxide scales and corrosion products. The corrosion potential and impedance were measured by anodic polarization and electrochemical impedance spectroscopy. According to the results, oxide scales on the hot-rolled strips mainly comprise iron and iron oxides. The correlation between mass gain and test time follows a power exponential rule in the damp-heat test. The corrosion products are found to be mainly composed of γ-Fe OOH, Fe3O4, ？-Fe OOH, and γ-Fe2O3. The contents of the corrosion products are different on the surfaces of the steels with and without oxide scales. The steel with oxide scales is found to show a higher corrosion resistance and lower corrosion rate.
基金Project(04JJ40035) supported by the Natural Science Foundation of Hunan Province, China Project(2003AA331090) supported by the High-tech Research and Development Program of China
文摘An analytical method was proposed to solve the mechanical problems of stamping a thin strip on an elastic foundation. The thin strip was divided into four parts according to its deformation and contact with the punch and the elastic foundation, especially an elastic-plastic part was considered in the deflection of the thin strip. Analytical solutions were derived individually for each part and two models were established with the help of elastic and plastic large deflection theories. Compatibility conditions between the neighboring parts of the thin strip constructed the non-linear equation group. Solutions were carried out by programming with a software. The deformation shape, the membrane force, and the moment and shear force of the deformed thin strip were obtained. The results of the two models were compared. The study shows that the method is effective.
文摘Vapor deposited coatings onto strip steel are a promising alternative as functional layers for corrosion protection or high abrasion resistance.Conventional coating systems have some limits regarding environmental compatibility,the range of coating materials and application properties. Physical vapor deposition(PVD) is an environment-friendly technology and enables nearly unlimited material and process variety.Electron beam high-rate evaporation with deposition rates up to some micrometers per second is the most productive PVD technology for low cost coating.The combination of evaporation with powerful plasma is an efficient way to improve the layer properties.The developed plasma sources can be used for special plasma enhanced chemical vapor deposition(PECVD) processes too. The paper gives an overview about the latest developments in these technologies.Furthermore,the paper explains some examples of new layer stacks onto steel strips.While enhanced corrosion protection can be obtained by magnesium,aluminium or copper containing coatings other functional surface properties come more and more in the focus of interest.For instance,decorative gold colored layers,transparent scratch resistant layers,hard coatings and photo catalytic layers were deposited on running steel strips.Functional layers and layer systems for energy saving and sun energy absorption by solar thermal effects and photo voltaics are under development.The coatings are prepared under the conditions of very high deposition rates using our in-line vacuum coater for metallic strips and sheets with the name MAXI.The influence of the process and plasma parameters on the layer properties were investigated and will be demonstrated for some applications.
