为探讨进行乡村建成环境主观评价(Subjective Evaluation of Built Environment,SEBE)时,适用于乡村留守老人使用主体的评价因子及尺度体系科学构建方法,选取雪峰山丘陵山区村落为研究对象,通过实地访谈和调研得到用于主观评价的语义词...为探讨进行乡村建成环境主观评价(Subjective Evaluation of Built Environment,SEBE)时,适用于乡村留守老人使用主体的评价因子及尺度体系科学构建方法,选取雪峰山丘陵山区村落为研究对象,通过实地访谈和调研得到用于主观评价的语义词、语义量词的初选库,然后制作成问卷向村民发放,最后对收集的问卷数据进行量化分析,确定主观评价语义词和语义量词。研究获得了适于留守老人使用主体的乡村环境主观评价14组评价因子的形容词对和5级、7级、9级的评价尺度标尺。乡村有当地的语言使用习惯,主观评价基于村民的习惯开展,需对空间场景及心理尺度进行精确描述,构建的“评价体系初选—乡村实地走访—数据数理统计—评价体系形成”的方法,为量化建成环境对使用主体的价值需求满足程度,建立了切实有效的乡村环境主观评价可行路径。展开更多
The reactive oxygen plasma cleaning was proved an efficient method to decrease the field emission effect of the HWR superconducting cavities on the vertical test platform.
Multicell superconducting radio frequency(SRF)elliptical cavities are proposed for efficient acceleration of proton beam in the Chinese initiative Accelerator Driven Subcritical System(CiADS).
RF Surface Technology Research Group was founded in August 2019.It was evolved from the former Supercon-ducting Radio Frequency(SRF)research group of Linac center.The primary research topics will be presented in this ...RF Surface Technology Research Group was founded in August 2019.It was evolved from the former Supercon-ducting Radio Frequency(SRF)research group of Linac center.The primary research topics will be presented in this report.展开更多
The Buffered Chemical Polishing(BCP),consisting of one volume of 40%HF,one volume of 65%HNO_(3) and two volumes of 85%H_(3)PO_(4),has been considered as a popular method for etching the inner surfaces of niobium cavit...The Buffered Chemical Polishing(BCP),consisting of one volume of 40%HF,one volume of 65%HNO_(3) and two volumes of 85%H_(3)PO_(4),has been considered as a popular method for etching the inner surfaces of niobium cavities after its fabrication,especially for lowβ(β<0.3)cavities.展开更多
After many years of worldwide exploration and improvement of the post treatment process,niobium(Nb)cavities are now approaching their fundamental limits both in terms of maximum acceleration field and in terms of surf...After many years of worldwide exploration and improvement of the post treatment process,niobium(Nb)cavities are now approaching their fundamental limits both in terms of maximum acceleration field and in terms of surface resistance at typical operating temperatures.展开更多
In 2018,detailed studies on RF induced plasma for the in-situ cleaning of the HWR cavity were conducted to improve the performance of the cavity.For the purpose of cleaning the HWR cavities in cryomodule,an apparatus ...In 2018,detailed studies on RF induced plasma for the in-situ cleaning of the HWR cavity were conducted to improve the performance of the cavity.For the purpose of cleaning the HWR cavities in cryomodule,an apparatus for the discharge experiments was designed at room temperature,which duplicates the assembly of cavities inside cryomodule,where the FPC was used for power coupling.展开更多
The Accelerator Driven System(ADS)consists of a high power proton accelerator,a high power heavy metal target,and a sub-critical fast reactor.The availability of the accelerator as high as more than 0.9 is one of the ...The Accelerator Driven System(ADS)consists of a high power proton accelerator,a high power heavy metal target,and a sub-critical fast reactor.The availability of the accelerator as high as more than 0.9 is one of the most critical issues in ADS.The superconducting resonators have very high Quality factor.That means the slight change of resonator will cause the big shift of frequency which is one of the mean sources of beam trips of the superconducting linear accelerator.From the operation of CAFe,it is investigated that high stability,low cost,and maintainability are the main characteristics of Superconducting RF resonators for ADS.展开更多
SRF cavities are the common accelerating structures for many accelerators nowadays.Since a series of external loads on the resonator walls predetermine the main working conditions of the SC cavities,the detailed inves...SRF cavities are the common accelerating structures for many accelerators nowadays.Since a series of external loads on the resonator walls predetermine the main working conditions of the SC cavities,the detailed investigation of their mechanical properties should be conducted in parallel with the main RF design.The effects of very high electromagnetic fields that result in strong Lorentz forces and the pressure on cavity walls from the helium tank that also deforms the cavity shape,the tuning scheme resulting in the change of accelerating field profile and mechanical eigen resonance of cavities which are the main source of the microphonics must be taken into account during integrated design of the resonator and its liquid helium vessel.展开更多
There are two types of HWR cavities have been developed in IMP for C-ADS Injector.HWR010s have been used to accelerate proton from 2.1 MeV to 10 MeV.There are 12 HWR010s assembled in two CMs.The taper type HWR015s hav...There are two types of HWR cavities have been developed in IMP for C-ADS Injector.HWR010s have been used to accelerate proton from 2.1 MeV to 10 MeV.There are 12 HWR010s assembled in two CMs.The taper type HWR015s have been used to accelerate proton from 10MeV to 18.5 MeV.There are 5 HWRs assembled in the third CM.Proton beam has been accelerated to 26 MeV by HWR010,HWR015 and Spoke021 in June 2017.The beam has been accelerated to 18.5 MeV by HWR010 and HWR015.The CMs in the tunnel are shown in Fig.1.展开更多
SRF cavities are operated at Meissner state,which al-lows the electro-magnetic wave only interacts with the very surface of the cavity.The penetration depth of Nb at 4.2 is^100 nm,which means more than 99%of the expen...SRF cavities are operated at Meissner state,which al-lows the electro-magnetic wave only interacts with the very surface of the cavity.The penetration depth of Nb at 4.2 is^100 nm,which means more than 99%of the expensive SRF grade Nb used on the SRF cavity is not involved in the interaction with the E-M wave.Fig.1 shows the schematics diagram of the interac-tion between magnetic field and a Nb coated Cu cavity.With a Nb film thicker than 3λ,the copper hide behind wouldn't be able to see the E-M wave nor generate RF dissipation.展开更多
文摘为探讨进行乡村建成环境主观评价(Subjective Evaluation of Built Environment,SEBE)时,适用于乡村留守老人使用主体的评价因子及尺度体系科学构建方法,选取雪峰山丘陵山区村落为研究对象,通过实地访谈和调研得到用于主观评价的语义词、语义量词的初选库,然后制作成问卷向村民发放,最后对收集的问卷数据进行量化分析,确定主观评价语义词和语义量词。研究获得了适于留守老人使用主体的乡村环境主观评价14组评价因子的形容词对和5级、7级、9级的评价尺度标尺。乡村有当地的语言使用习惯,主观评价基于村民的习惯开展,需对空间场景及心理尺度进行精确描述,构建的“评价体系初选—乡村实地走访—数据数理统计—评价体系形成”的方法,为量化建成环境对使用主体的价值需求满足程度,建立了切实有效的乡村环境主观评价可行路径。
文摘The reactive oxygen plasma cleaning was proved an efficient method to decrease the field emission effect of the HWR superconducting cavities on the vertical test platform.
文摘Multicell superconducting radio frequency(SRF)elliptical cavities are proposed for efficient acceleration of proton beam in the Chinese initiative Accelerator Driven Subcritical System(CiADS).
文摘RF Surface Technology Research Group was founded in August 2019.It was evolved from the former Supercon-ducting Radio Frequency(SRF)research group of Linac center.The primary research topics will be presented in this report.
文摘The Buffered Chemical Polishing(BCP),consisting of one volume of 40%HF,one volume of 65%HNO_(3) and two volumes of 85%H_(3)PO_(4),has been considered as a popular method for etching the inner surfaces of niobium cavities after its fabrication,especially for lowβ(β<0.3)cavities.
文摘After many years of worldwide exploration and improvement of the post treatment process,niobium(Nb)cavities are now approaching their fundamental limits both in terms of maximum acceleration field and in terms of surface resistance at typical operating temperatures.
文摘In 2018,detailed studies on RF induced plasma for the in-situ cleaning of the HWR cavity were conducted to improve the performance of the cavity.For the purpose of cleaning the HWR cavities in cryomodule,an apparatus for the discharge experiments was designed at room temperature,which duplicates the assembly of cavities inside cryomodule,where the FPC was used for power coupling.
文摘The Accelerator Driven System(ADS)consists of a high power proton accelerator,a high power heavy metal target,and a sub-critical fast reactor.The availability of the accelerator as high as more than 0.9 is one of the most critical issues in ADS.The superconducting resonators have very high Quality factor.That means the slight change of resonator will cause the big shift of frequency which is one of the mean sources of beam trips of the superconducting linear accelerator.From the operation of CAFe,it is investigated that high stability,low cost,and maintainability are the main characteristics of Superconducting RF resonators for ADS.
文摘SRF cavities are the common accelerating structures for many accelerators nowadays.Since a series of external loads on the resonator walls predetermine the main working conditions of the SC cavities,the detailed investigation of their mechanical properties should be conducted in parallel with the main RF design.The effects of very high electromagnetic fields that result in strong Lorentz forces and the pressure on cavity walls from the helium tank that also deforms the cavity shape,the tuning scheme resulting in the change of accelerating field profile and mechanical eigen resonance of cavities which are the main source of the microphonics must be taken into account during integrated design of the resonator and its liquid helium vessel.
文摘There are two types of HWR cavities have been developed in IMP for C-ADS Injector.HWR010s have been used to accelerate proton from 2.1 MeV to 10 MeV.There are 12 HWR010s assembled in two CMs.The taper type HWR015s have been used to accelerate proton from 10MeV to 18.5 MeV.There are 5 HWRs assembled in the third CM.Proton beam has been accelerated to 26 MeV by HWR010,HWR015 and Spoke021 in June 2017.The beam has been accelerated to 18.5 MeV by HWR010 and HWR015.The CMs in the tunnel are shown in Fig.1.
文摘SRF cavities are operated at Meissner state,which al-lows the electro-magnetic wave only interacts with the very surface of the cavity.The penetration depth of Nb at 4.2 is^100 nm,which means more than 99%of the expensive SRF grade Nb used on the SRF cavity is not involved in the interaction with the E-M wave.Fig.1 shows the schematics diagram of the interac-tion between magnetic field and a Nb coated Cu cavity.With a Nb film thicker than 3λ,the copper hide behind wouldn't be able to see the E-M wave nor generate RF dissipation.
基金National Natural Science Foundation of China(11622217)Key Research Project of Frontier Science from Chinese Academy of Sciences(QYZDY-SSW-JSC019)The National Key Project of Scientific Instrument and Equipment Development(11327802)
