The cooling storage ring(CSR)external-target experiment(CEE)is a spectrometer used in construction to study the properties of nuclear matter in high-baryon density regions at the Heavy-Ion Research Facility in Lanzhou...The cooling storage ring(CSR)external-target experiment(CEE)is a spectrometer used in construction to study the properties of nuclear matter in high-baryon density regions at the Heavy-Ion Research Facility in Lanzhou(HIRFL).This study presents the design,simulation,manufacturing,and testing of a half-size prototype of a multi-wire drift chamber(MWDC)for the CEE.First,the performance of the MWDC connected to homemade electronics was simulated.The results demonstrated that an energy resolution of 18.5% for 5.9-keV X-rays and a position resolution of 194μm for protons can be achieved by the current design.Because the size of the largest MWDC reached 176 cm×314 cm,a set of 98 cm×98 cm prototypes was built using the new techniques.The positioning accuracy of the anode wires in this prototype is better than 20μm.After optimization,using commercially available electronics,the prototype can achieved an energy resolution of 19.7%for a^(55)Fe X-ray source.The CEE-MWDC detector and electronics were simultaneously tested.An energy resolution of 22%was achieved for the^(55)Fe source;the track residuals were approximately 330μm for the cosmic rays.The results demonstrate that the current design and techniques meet the requirements of the CEE-MWDC array.展开更多
A half-size prototype of the multi wire drift chamber for the cooling storage ring external-target experiment(CEE)was assembled and tested in the 350 MeV/u Kr+Fe reactions at the heavy-ion research facility in Lanzhou...A half-size prototype of the multi wire drift chamber for the cooling storage ring external-target experiment(CEE)was assembled and tested in the 350 MeV/u Kr+Fe reactions at the heavy-ion research facility in Lanzhou.The prototype consists of six sense layers,where the sense wires are stretched in three directions X,U,and V;meeting 0?,30?,and-30?,respectively,with respect to the vertical axis.The sensitive area of the prototype is 76 cm×76 cm.The amplified and shaped signals from the anode wires were digitized in a serial capacity array.When operating at a high voltage of 1500 V on the anode wires,the efficiency for each layer is greater than 95%.The tracking residual is approximately 301±2μm.This performance satisfies the requirements of CEE.展开更多
Background The Multi-Wire Drift Chamber(MWDC)is among the significant detectors for CSR External Target Experiment(CEE).We require the MWDC detector’s front-end readout circuits to have a high integration,high count r...Background The Multi-Wire Drift Chamber(MWDC)is among the significant detectors for CSR External Target Experiment(CEE).We require the MWDC detector’s front-end readout circuits to have a high integration,high count rate,and big dynamic range in order to measure the tracks of fore-angle products.Purpose In this paper,MWDC readout electronics verification system is shown,which is based on the front-end amplifier chip and Switched Capacitor Array(SCA)chip independently established by the project team.Results In the dynamic input range of 14 fC–950 fC,the readout electronics’energy measurement linearity is greater than 1%.The test results with MWDC illustrate that with a 55Fe source an energy resolution of 22.4%was acquired,and with cosmic rays the residual error is less than 400um.展开更多
The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this paper.The influences of their different roles in model construction of str...The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this paper.The influences of their different roles in model construction of structural topology optimization are also discussed.Furthermore,two structural topology optimization models,optimizing a performance index under the limitation of an economic index,represented by the minimum compliance with a volume constraint（MCVC）model,and optimizing an economic index under the limitation of a performance index,represented by the minimum weight with a displacement constraint（MWDC）model,are presented.Based on a comparison of numerical example results,the conclusions can be summarized as follows：（1）under the same external loading and displacement performance conditions,the results of the MWDC model are almost equal to those of the MCVC model;（2）the MWDC model overcomes the difficulties and shortcomings of the MCVC model;this makes the MWDC model more feasible in model construction;（3）constructing a model of minimizing an economic index under the limitations of performance indexes is better at meeting the needs of practical engineering problems and completely satisfies safety and economic requirements in mechanical engineering,which have remained unchanged since the early days of mechanical engineering.展开更多
With the rapid deployment of 5G and the emergence of 6G technologies,the demand for high-performance microwave dielectric ceramics(MWDCs)has increased.This study developed Y_(3)MgAl_(3)GeO_(12)(YMAG)garnet ceramics to...With the rapid deployment of 5G and the emergence of 6G technologies,the demand for high-performance microwave dielectric ceramics(MWDCs)has increased.This study developed Y_(3)MgAl_(3)GeO_(12)(YMAG)garnet ceramics to meet 5G/6G requirements for low signal delay,low loss,and high-temperature stability.YMAG ceramics synthesized via a solid-state reaction were characterized for phase composition,crystal structure,microstructure,and microwave dielectric properties.The results revealed that YMAG ceramics exhibited excellent microwave performance:a permittivity(εr)of 9.86,a quality factor(Q×f)of 89,000 GHz,and a temperature coefficient of resonant frequency(τf)of−40 ppm/°C.Far-infrared and terahertz(THz)spectroscopic analyses verified the low intrinsic dielectric loss and frequency-stable dielectric characteristics of the material in high-frequency ranges.Temperature-dependent dielectric measurements coupled with thermal expansion studies revealed outstanding stability in this material,as evidenced by its low coefficient of thermal expansion(αL=9.13 ppm/°C).To attain near-zeroτf,we added TiO_(2)as a positiveτf compensation agent.This strategy effectively tuned theτf value to within|τf|<10 ppm/°C while preserving excellent microwave dielectric performance(Q×f≈43,000 GHz).Furthermore,a rectangular dielectric resonator antenna(DRA)designed with the optimized YMAG–TiO_(2)composite demonstrated excellent impedance matching(VSWR=1.02)and high radiation efficiency(>90%)in the X-band(10.21 GHz),validating its potential for 5G/6G applications.This work provides a novel approach for developing high-performance MWDCs for next-generation communication technologies and emphasizes the critical role of material design and optimization in achieving superior microwave properties.展开更多
The explosive process of 5G communication evokes the urgent demand of miniaturized and integrated dielectric ceramics filter It is a pressing need to advance the development of dielectric ceramics utilization of emerg...The explosive process of 5G communication evokes the urgent demand of miniaturized and integrated dielectric ceramics filter It is a pressing need to advance the development of dielectric ceramics utilization of emerging technology to design new materials and understand the polarization mechanism.This review provides the summary of the study of microwave dielectric ceramics(MWDCs)sintered higher than 1000℃ from 2010 up to now,with the purpose of taking a broad and historical view of these ceramics and illustrating research directions.To date,researchers endeavor to explain the structure-property relationship of ceramics with multitude of approaches and design a new formula or strategy to obtain excellent microwave dielectric properties.There are variety of factors that impact the permittivity,dielectric loss,and temperature stability of dielectric materials,covering intrinsic and extrinsic factors.Many of these factors are often intertwined,which can complicate new dielectric material discovery and the mechanism investigation.Because of the various ceramics systems,pseudo phase diagram was used to classify the dielectric materials based on the composition.In this review,the ceramics were firstly divided into ternary systems,and then brief description of the experimental probes and complementary theoretical methods that have been used to discern the intrinsic polarization mechanisms and the origin of intrinsic loss was mentioned.Finally,some perspectives on the future outlook for high-temperature MWDCs were offered based on the synthesis method,characterization techniques,and significant theory developments.展开更多
Microwave dielectric ceramics(MWDCs)with low dielectric constant and low dielectric loss are desired in contemporary society,where the communication frequency is developing to high frequency(sub-6G).Herein,Nd_(2)(Zr_(...Microwave dielectric ceramics(MWDCs)with low dielectric constant and low dielectric loss are desired in contemporary society,where the communication frequency is developing to high frequency(sub-6G).Herein,Nd_(2)(Zr_(1−x)Ti_(x))_(3)(MoO_(4))_(9)(NZ_(1−x)T_(x)M,x=0.02-0.10)ceramics were prepared through a solid-phase process.According to X-ray diffraction(XRD)patterns,the ceramics could form a pure crystal structure with the R3c(167)space group.The internal parameters affecting the properties of the ceramics were calculated and analyzed by employing Clausius-Mossotti relationship,Shannon’s rule,and Phillips-van Vechten-Levine(P-V-L)theory.Furthermore,theoretical dielectric loss of the ceramics was measured and analyzed by a Fourier transform infrared(IR)radiation spectrometer.Notably,when x=0.08 and sintered at 700℃,optimal microwave dielectric properties of the ceramics were obtained,including a dielectric constant(ε_(r))=10.94,Q·f=82,525 GHz(at 9.62 GHz),and near-zero resonant frequency temperature coefficient(τ_(f))=−12.99 ppm/℃.This study not only obtained an MWDC with excellent properties but also deeply analyzed the effects of Ti^(4+)on the microwave dielectric properties and chemical bond characteristics of Nd_(2)Zr_(3)(MoO_(4))_(9)(NZM),which laid a solid foundation for the development of rare-earth molybdate MWDC system.展开更多
基金supported by the Research Program of the National Major Research Instruments(No.11927901)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB34000000)+3 种基金the Function Development Project of Chinese Academy of Sciences(No.2022G101)National Key R&D Program of China(No.2018YFE0205200)Natural Science Foundation of China(Nos.11875301,11875302,U1867214,U1832105,U1832167)CAS"Light of West China"Program。
文摘The cooling storage ring(CSR)external-target experiment(CEE)is a spectrometer used in construction to study the properties of nuclear matter in high-baryon density regions at the Heavy-Ion Research Facility in Lanzhou(HIRFL).This study presents the design,simulation,manufacturing,and testing of a half-size prototype of a multi-wire drift chamber(MWDC)for the CEE.First,the performance of the MWDC connected to homemade electronics was simulated.The results demonstrated that an energy resolution of 18.5% for 5.9-keV X-rays and a position resolution of 194μm for protons can be achieved by the current design.Because the size of the largest MWDC reached 176 cm×314 cm,a set of 98 cm×98 cm prototypes was built using the new techniques.The positioning accuracy of the anode wires in this prototype is better than 20μm.After optimization,using commercially available electronics,the prototype can achieved an energy resolution of 19.7%for a^(55)Fe X-ray source.The CEE-MWDC detector and electronics were simultaneously tested.An energy resolution of 22%was achieved for the^(55)Fe source;the track residuals were approximately 330μm for the cosmic rays.The results demonstrate that the current design and techniques meet the requirements of the CEE-MWDC array.
基金supported by the National Natural Science Foundation of China(Nos.11927901,11875301,11875302,U1867214,U1832105,U1832167)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34000000)+2 种基金the National Key R&D Program of China(No.2018YFE0205200)the CAS"Light of West China"Programthe Tsinghua University Initiative Scientific Research Program。
文摘A half-size prototype of the multi wire drift chamber for the cooling storage ring external-target experiment(CEE)was assembled and tested in the 350 MeV/u Kr+Fe reactions at the heavy-ion research facility in Lanzhou.The prototype consists of six sense layers,where the sense wires are stretched in three directions X,U,and V;meeting 0?,30?,and-30?,respectively,with respect to the vertical axis.The sensitive area of the prototype is 76 cm×76 cm.The amplified and shaped signals from the anode wires were digitized in a serial capacity array.When operating at a high voltage of 1500 V on the anode wires,the efficiency for each layer is greater than 95%.The tracking residual is approximately 301±2μm.This performance satisfies the requirements of CEE.
基金supported by the National Natural Science Foundation of China(Nos.E11927901 and E911530101).
文摘Background The Multi-Wire Drift Chamber(MWDC)is among the significant detectors for CSR External Target Experiment(CEE).We require the MWDC detector’s front-end readout circuits to have a high integration,high count rate,and big dynamic range in order to measure the tracks of fore-angle products.Purpose In this paper,MWDC readout electronics verification system is shown,which is based on the front-end amplifier chip and Switched Capacitor Array(SCA)chip independently established by the project team.Results In the dynamic input range of 14 fC–950 fC,the readout electronics’energy measurement linearity is greater than 1%.The test results with MWDC illustrate that with a 55Fe source an energy resolution of 22.4%was acquired,and with cosmic rays the residual error is less than 400um.
基金supported by the National Natural Science Foundation of China(Grant 11172013)
文摘The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this paper.The influences of their different roles in model construction of structural topology optimization are also discussed.Furthermore,two structural topology optimization models,optimizing a performance index under the limitation of an economic index,represented by the minimum compliance with a volume constraint（MCVC）model,and optimizing an economic index under the limitation of a performance index,represented by the minimum weight with a displacement constraint（MWDC）model,are presented.Based on a comparison of numerical example results,the conclusions can be summarized as follows：（1）under the same external loading and displacement performance conditions,the results of the MWDC model are almost equal to those of the MCVC model;（2）the MWDC model overcomes the difficulties and shortcomings of the MCVC model;this makes the MWDC model more feasible in model construction;（3）constructing a model of minimizing an economic index under the limitations of performance indexes is better at meeting the needs of practical engineering problems and completely satisfies safety and economic requirements in mechanical engineering,which have remained unchanged since the early days of mechanical engineering.
基金supported by the Guangxi Science and Technology Plan Project(No.GuikeAD25069100)the Guangxi Natural Science Foundation Project(No.2024GXNSFDA010060).
文摘With the rapid deployment of 5G and the emergence of 6G technologies,the demand for high-performance microwave dielectric ceramics(MWDCs)has increased.This study developed Y_(3)MgAl_(3)GeO_(12)(YMAG)garnet ceramics to meet 5G/6G requirements for low signal delay,low loss,and high-temperature stability.YMAG ceramics synthesized via a solid-state reaction were characterized for phase composition,crystal structure,microstructure,and microwave dielectric properties.The results revealed that YMAG ceramics exhibited excellent microwave performance:a permittivity(εr)of 9.86,a quality factor(Q×f)of 89,000 GHz,and a temperature coefficient of resonant frequency(τf)of−40 ppm/°C.Far-infrared and terahertz(THz)spectroscopic analyses verified the low intrinsic dielectric loss and frequency-stable dielectric characteristics of the material in high-frequency ranges.Temperature-dependent dielectric measurements coupled with thermal expansion studies revealed outstanding stability in this material,as evidenced by its low coefficient of thermal expansion(αL=9.13 ppm/°C).To attain near-zeroτf,we added TiO_(2)as a positiveτf compensation agent.This strategy effectively tuned theτf value to within|τf|<10 ppm/°C while preserving excellent microwave dielectric performance(Q×f≈43,000 GHz).Furthermore,a rectangular dielectric resonator antenna(DRA)designed with the optimized YMAG–TiO_(2)composite demonstrated excellent impedance matching(VSWR=1.02)and high radiation efficiency(>90%)in the X-band(10.21 GHz),validating its potential for 5G/6G applications.This work provides a novel approach for developing high-performance MWDCs for next-generation communication technologies and emphasizes the critical role of material design and optimization in achieving superior microwave properties.
基金supported by the National Natural Science Foundation of China(Grant No.51872037).
文摘The explosive process of 5G communication evokes the urgent demand of miniaturized and integrated dielectric ceramics filter It is a pressing need to advance the development of dielectric ceramics utilization of emerging technology to design new materials and understand the polarization mechanism.This review provides the summary of the study of microwave dielectric ceramics(MWDCs)sintered higher than 1000℃ from 2010 up to now,with the purpose of taking a broad and historical view of these ceramics and illustrating research directions.To date,researchers endeavor to explain the structure-property relationship of ceramics with multitude of approaches and design a new formula or strategy to obtain excellent microwave dielectric properties.There are variety of factors that impact the permittivity,dielectric loss,and temperature stability of dielectric materials,covering intrinsic and extrinsic factors.Many of these factors are often intertwined,which can complicate new dielectric material discovery and the mechanism investigation.Because of the various ceramics systems,pseudo phase diagram was used to classify the dielectric materials based on the composition.In this review,the ceramics were firstly divided into ternary systems,and then brief description of the experimental probes and complementary theoretical methods that have been used to discern the intrinsic polarization mechanisms and the origin of intrinsic loss was mentioned.Finally,some perspectives on the future outlook for high-temperature MWDCs were offered based on the synthesis method,characterization techniques,and significant theory developments.
基金supported by the National Natural Science Foundation of China (Nos.51972143 and 52272126)State Key Laboratory of New Ceramics and Fine Processing,Tsinghua University (No.KFZD202101).
文摘Microwave dielectric ceramics(MWDCs)with low dielectric constant and low dielectric loss are desired in contemporary society,where the communication frequency is developing to high frequency(sub-6G).Herein,Nd_(2)(Zr_(1−x)Ti_(x))_(3)(MoO_(4))_(9)(NZ_(1−x)T_(x)M,x=0.02-0.10)ceramics were prepared through a solid-phase process.According to X-ray diffraction(XRD)patterns,the ceramics could form a pure crystal structure with the R3c(167)space group.The internal parameters affecting the properties of the ceramics were calculated and analyzed by employing Clausius-Mossotti relationship,Shannon’s rule,and Phillips-van Vechten-Levine(P-V-L)theory.Furthermore,theoretical dielectric loss of the ceramics was measured and analyzed by a Fourier transform infrared(IR)radiation spectrometer.Notably,when x=0.08 and sintered at 700℃,optimal microwave dielectric properties of the ceramics were obtained,including a dielectric constant(ε_(r))=10.94,Q·f=82,525 GHz(at 9.62 GHz),and near-zero resonant frequency temperature coefficient(τ_(f))=−12.99 ppm/℃.This study not only obtained an MWDC with excellent properties but also deeply analyzed the effects of Ti^(4+)on the microwave dielectric properties and chemical bond characteristics of Nd_(2)Zr_(3)(MoO_(4))_(9)(NZM),which laid a solid foundation for the development of rare-earth molybdate MWDC system.
