Background:Traditional Chinese medicine(TCM)is commonly used for the diagnosis and treatment of insomnia,with tongue diagnosis being particularly important.The aim of our study was to develop and validate a novel tong...Background:Traditional Chinese medicine(TCM)is commonly used for the diagnosis and treatment of insomnia,with tongue diagnosis being particularly important.The aim of our study was to develop and validate a novel tongue imaging-based radiomics(TIR)method for accurately diagnosing insomnia severity.Methods:This two-center analysis prospectively enrolled 399 patients who underwent tongue imaging between July and October 2021 and divided them into primary and validation cohorts by study center.Here,we referred to the Insomnia Severity Index(ISI)standard and the degree of insomnia was evaluated as absent,subthreshold,moderate,or severe.For developed the TIR diagnostic tool,a U-Net algorithm was used to segment tongue images.Subsequently,seven imaging features were selected from the extracted high-throughout radiomics features using the least absolute shrinkage and selection operator algorithm.Then,the final radiomics model was developed in the primary cohort and tested in the independent validation cohort.Finally,we assessed and compared the diagnostic performance differences between TCM tongue diagnosis and our TIR diagnostic tool with the ISI gold standard.The confusion matrix was calculated to evaluate the diagnostic performance.Results:Seven tongue imaging features were selected to build the TIR tool,with showing good correlations with the insomnia degree.The TIR method had an accuracy of 0.798,a macro-average sensitivity of 0.78,a macro-average specificity of 0.906,a weighted-average sensitivity of 0.798,and a weighted specificity of 0.916,showing a significantly better performance compared to the average performance of three experienced TCM physicians(mean accuracy of 0.458,P<0.01).Conclusions:The preliminary study demonstrates the potential application of TIR in the diagnosis of insomnia degree and measurement of sleep health.The integration of quantitative imaging analysis and machine learning algorithms holds promise for advancing both of TCM and precision sleep medicine.展开更多
Senior study travel,as an emerging form of tourism,combines the dual characteristics of educational learning and leisure travel.It not only meets the elderly’s desire for spiritual and cultural life and self-fulfillm...Senior study travel,as an emerging form of tourism,combines the dual characteristics of educational learning and leisure travel.It not only meets the elderly’s desire for spiritual and cultural life and self-fulfillment but also promotes the construction of a healthy aging society.This study comprehensively uses methods such as literature analysis,interviews,and case studies to analyze the current status and existing problems of the senior study travel market.Based on the 7Ps service marketing model,it explores service marketing strategies for the senior study travel market,aiming to provide reference and guidance for related tourism enterprises to supply more attractive senior study travel services.展开更多
A 3W1 superconducting wiggler(SCW)with the pole gap of 68 mm was successfully tested and installed in a BEPC II storage ring in November,2019.The goal of zero liquid helium consumption was achieved,and the cryogenic s...A 3W1 superconducting wiggler(SCW)with the pole gap of 68 mm was successfully tested and installed in a BEPC II storage ring in November,2019.The goal of zero liquid helium consumption was achieved,and the cryogenic system exhibited a 12%residual cooling capacity(approximately 0.69 W@4.2 K).The 3W1-SCW was set to operate at 2.49 T and has been operating for more than seven months.Three instances of magnet quenching occurred during the normal operation.The evaporated helium gas can be recycled to the helium gas recycling system when the pressure in the helium tank is higher than the parameter value(the setpoint of the pressure value is 1.2 bara).The cryogenic system can be recovered within 4 h if sufficient liquid helium is available to inject into the cryostat.展开更多
In order to achieve the optimized design of a cased telescoped ammunition(CTA) interior ballistic design,a genetic algorithm was introduced into the optimal design of CTA interior ballistics with coupling the CTA inte...In order to achieve the optimized design of a cased telescoped ammunition(CTA) interior ballistic design,a genetic algorithm was introduced into the optimal design of CTA interior ballistics with coupling the CTA interior ballistic model. Aiming at the interior ballistic characteristics of a CTA gun, the goal of CTA interior ballistic design is to obtain a projectile velocity as large as possible. The optimal design of CTA interior ballistic is carried out using a genetic algorithm by setting peak pressure, changing the chamber volume and gun powder charge density. A numerical simulation of interior ballistics based on a 35 mm CTA firing experimental scheme was conducted and then the genetic algorithm was used for numerical optimization. The projectile muzzle velocity of the optimized scheme is increased from 1168 m/s for the initial experimental scheme to 1182 m/s. Then four optimization schemes were obtained with several independent optimization processes. The schemes were compared with each other and the difference between these schemes is small. The peak pressure and muzzle velocity of these schemes are almost the same. The result shows that the genetic algorithm is effective in the optimal design of the CTA interior ballistics. This work will be lay the foundation for further CTA interior ballistic design.展开更多
The Accelerator Driven Sub-critical(ADS)system is a strategic plan to solve the nuclear waste problem for nuclear power plants in China.High-energy particle accelerators and colliders contain long strings of supercond...The Accelerator Driven Sub-critical(ADS)system is a strategic plan to solve the nuclear waste problem for nuclear power plants in China.High-energy particle accelerators and colliders contain long strings of superconducting devices,superconducting radio frequency cavities,and magnets,which may require cooling by 2 K superfluid helium(HeliumⅡ).2 K superfluid helium cryogenic system has become a research hot spot in the field of superconducting accelerators.In this study,the ADS Injector-I 2 K cryogenic system is examined in detail.The cryogenic system scheme design,key equipment,and technology design,such as the 2 K Joule–Thomson(J–T)heat exchanger and cryomodules CM1+CM2 design,are examined,in addition to the commissioning and operation of the cryogenic system.The ADS Injector-I 2 K cryogenic system is the first 100 W superfluid helium system designed and built independently in China.The ADS proton beam reached 10 Me V at 10 m A in July 2016 and 10 Me V at 2 m A in continuous mode in January 2017 and has been operated reliably for over 15,000 h,proving that the design of ADS Injector-I 2 K cryogenic system,the key equipment,and technology research are reasonable,reliable,and meet the requirements.The research into key technologies provides valuable engineering experience that can be helpful for future projects such as CI-ADS(China Initiative Accelerator-Driven System),SHINE(Shanghai High Repetition Rate XFEL and Extreme Light Facility),PAPS(Platform of Advanced Photon Source Technology),and CEPC(Circular Electron-Positron Collider),thereby developing national expertise in the field of superfluid helium cryogenic systems.展开更多
One of the most important devices for the High Energy Photon Source Test Facility project,the 2.6 T 32-pole 3W1 superconducting wiggler,was designed by the Institute of High Energy Physics(IHEP);its magnetic gap is 68...One of the most important devices for the High Energy Photon Source Test Facility project,the 2.6 T 32-pole 3W1 superconducting wiggler,was designed by the Institute of High Energy Physics(IHEP);its magnetic gap is 68 mm,and its storage energy is 286 kJ.It will be installed at the storage ring of the Beijing Electron Positron Collider Upgrade Project at the IHEP to replace the old permanent wiggler.The primary purpose of the cryostat is to create a safe and reliable system and realize long-term operation with zero liquid helium consumption.To maintain liquid helium temperature,four identical two-stage cryocoolers are placed symmetrically at the wiggler ends.The cryostat has only one 60 K thermal shield,which is used to reduce the heat load to the liquid helium vessel.The cryostat has several novel features,including a suspension system with little heat leakage that is self-centered during cooling of the cryostat,a special copper liner and high-efficiency condensers,three pairs of binary current leads,and three-level safety design.The cryogenic system has been cooled three times,and the residual cooling capacity is approximately 0.41 W at 4.2 K without current.展开更多
A complex multiple flame structure is formed during the combustion of AP/HTPB base bleed propellant.The AP monopropellant flame is concentrated in a thin zone above the burning surface of AP crystal to maintain self-s...A complex multiple flame structure is formed during the combustion of AP/HTPB base bleed propellant.The AP monopropellant flame is concentrated in a thin zone above the burning surface of AP crystal to maintain self-sustained decomposition.Due to the low temperature near the burning surface,the diffusion between the decomposition products of AP and the pyrolysis products of HTPB occurs,and a partly pre-mixed diffusion flame structure-leading edge flame(LEF)is formed.The effects of pressure,chemical reaction rate and AP particle size on diffusion flame structure in the range from 20 atm to 100 atm are discussed.The Peclet number increases from 6.64 at 20 atm to 21.91 at 100 atm when AP particle size is 140 mm.The high temperature zone is blown away from the burning surface because the convective transport rate increases with the increase in Peclet number.The chemical reaction rate is enhanced and the diffusion mixing is inhibited as Damkohler number increases.The chemical heat release is more concentrated and the chemical reaction zone becomes narrow when Damkohler number changes from 330 at20 atm to 4700 at 100 atm.When AP particle diameter is decreased to 60 mm,the diffusion time scale is reduced due to the reduced diffusion length scale.So the diffusion mixing is enhanced and a more pre-mixed flame is formed.The burning rate increases because the more pre-mixed heat release increases the heat feedback to the HTPB binder.展开更多
A 16-pole superconducting multipole wiggler with a large gap of 68 mm was designed and fabricated to serve as a multipole wiggler for HEPS-TF.The wiggler consists of 16 pairs of NbTi superconducting coils with a perio...A 16-pole superconducting multipole wiggler with a large gap of 68 mm was designed and fabricated to serve as a multipole wiggler for HEPS-TF.The wiggler consists of 16 pairs of NbTi superconducting coils with a period length of 170 mm,and its maximum peak field is 2.6 Tesla.In magnet design,magnet poles were optimized.Furthermore,the Lorentz force on the coils and electromagnetic force between the upper and lower halves were computed and analyzed along with the stored energy and inductance at different currents.To enhance the critical current of the magnet coil,all the pole coils selected for the magnet exhibited excellent performance,and appropriate prestress derived from the coil force analysis was applied to the pole coils during magnet assembly.The entire magnet structure was immersed in 4.2-K liquid helium in the cryostat cooled solely by four two-stage cryocoolers,and the performance test of the superconducting wiggler was appropriately completed.Based on the measured results,the first and second field integrals on the axis of the superconducting wiggler were significantly improved at different field levels after the compensation of the corrector coils.Subsequently,the wiggler was successfully installed in the storage ring of BEPCII operation with beams.展开更多
The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
Measuring topological invariants is an essential task in characterizing topological phases of matter.They are usually obtained from the number of edge states due to the bulk-edge correspondence or from interference si...Measuring topological invariants is an essential task in characterizing topological phases of matter.They are usually obtained from the number of edge states due to the bulk-edge correspondence or from interference since they are integrals of the geometric phases in the energy band.It is commonly believed that the bulk band structures could not be directly used to obtain the topological invariants.Here,we implement the experimental extraction of Zak phase from the bulk band structures of a Su-Schrieffer-Heeger(SSH)model in the synthetic frequency dimension.Such synthetic SSH lattices are constructed in the frequency axis of light,by controlling the coupling strengths between the symmetric and antisymmetric supermodes of two bichromatically driven rings.We measure the transmission spectra and obtain the projection of the time-resolved band structure on lattice sites,where a strong contrast between the non-trivial and trivial topological phases is observed.The topological Zak phase is naturally encoded in the bulk band structures of the synthetic SSH lattices,which can hence be experimentally extracted from the transmission spectra in a fiber-based modulated ring platform using a laser with telecom wavelength.Our method of extracting topological phases from the bulk band structure can be further extended to characterize topological invariants in higher dimensions,while the exhibited trivial and non-trivial transmission spectra from the topological transition may find future applications in optical communications.展开更多
COVID-19 has seriously threatened public health,and transdermal vaccination is an effective way to prevent pathogen infection.Microneedles(MNs)can damage the stratum corneum to allow passive diffusion of vaccine macro...COVID-19 has seriously threatened public health,and transdermal vaccination is an effective way to prevent pathogen infection.Microneedles(MNs)can damage the stratum corneum to allow passive diffusion of vaccine macromolecules,but the delivery effciency is low,while iontophoresis can actively promote transdermal delivery but fails to transport vaccine macromolecules due to the barrier of the stratum corneum.Herein,we developed a wearable iontophoresis-driven MN patch and its iontophoresis-driven device for active and effcient transdermal vaccine macromolecule delivery.Polyacrylamide/chitosan hydrogels with good biocompatibility,excellent conductivity,high elasticity,and a large loading capacity were prepared as the key component for vaccine storage and active iontophoresis.The transdermal vaccine delivery strategy of the iontophoresis-driven MN patch is“press and poke,iontophoresis-driven delivery,and immune response”.We demonstrated that the synergistic effect of MN puncture and iontophoresis significantly promoted transdermal vaccine delivery effciency.In vitro experiments showed that the amount of ovalbumin delivered transdermally using the iontophoresis-driven MN patch could be controlled by the iontophoresis current.In vivo immunization studies in BALB/c mice demonstrated that transdermal inoculation of ovalbumin using an iontophoresis-driven MN patch induced an effective immune response that was even stronger than that of traditional intramuscular injection.Moreover,there was little concern about the biosafety of the iontophoresis-driven MN patch.This delivery system has a low cost,is user-friendly,and displays active delivery,showing great potential for vaccine self-administration at home.展开更多
In order to study Brassica napus fatty acid （FA） metabolism and relevant regulatory networks, a systematic identification of fatty acid （FA） biosynthesis-related genes was conducted. Following gene identification,...In order to study Brassica napus fatty acid （FA） metabolism and relevant regulatory networks, a systematic identification of fatty acid （FA） biosynthesis-related genes was conducted. Following gene identification, gene expression profiles during B. napus seed development and FA metabolism were performed by cDNA chip hybridization （〉8000 EST clones from seed）. The results showed that FA biosynthesis and regulation, and carbon flux, were conserved between B. napus and Arabidopsis. However, a more critical role of starch metabolism was detected for B. napus seed FA metabolism and storage-component accumulation when compared with Arabidopsis. In addition, a crucial stage for the transition of seed-to-sink tissue was 17-21 d after flowering （DAF）, whereas FA biosynthesis-related genes were highly expressed pri- marily at 21 DAF. Hormone （auxin and jasmonate） signaling is found to be important for FA metabolism. This study helps to reveal the global regulatory network of FA metabolism in developing B. napus seeds.展开更多
Purpose The accelerator-driven subcritical system(ADS)is the internationally recognized key technology of nuclear waste problem treatment,of which superconducting proton linac is an important part.With the support of ...Purpose The accelerator-driven subcritical system(ADS)is the internationally recognized key technology of nuclear waste problem treatment,of which superconducting proton linac is an important part.With the support of the strategic science and technology pilot project of the Chinese Academy of Sciences,the Institute of High Energy Physics of the Chinese Academy of Sciences took the lead in the research of 325 MHz superconducting proton linac,which is called ADS Injector I.The superconducting accelerator part of ADS Injector I mainly consists of 14 spoke-type superconducting cavities withβ0.12.At the same time,the research work of various cavities with differentβvalues and different frequencies is also carried out to lay the technical and technological foundation for ADS main accelerator.The only way to determine whether the superconducting cavity can reach the design target and whether it can be installed into the cryostat is the vertical test at cryogenic.As the only way to test the microwave performance of the superconducting cavity at low temperature,the vertical test can accurately test the acceleration gradient Eacc and the corresponding quality factor Q0 of the superconducting cavity.The design and construction of the superconducting cavity vertical test facility is based on the practical needs of the pilot project and the long-term development of the superconducting accelerator.Methods This paper mainly introduces the design and construction of the cryogenic vertical test system for the superconducting cavity of ADS Injector I,including the system scheme design,process design,heat load analysis,2 K superfluid helium obtaining method,system commissioning and operation,etc.Results and Conclusion The static heat leakage at 2 K of the 2 K superfluid helium vertical test system of ADS Injector I is 1.624W,which has reached the international advanced level.The 2 K superfluid helium vertical test system of ADS Injector I after constructed not only meets the test requirements of ADS pilot project,but also conducts 4 K and 2 K vertical tests for other different types of superconducting cavities and relevant cryogenic experiments.展开更多
The incidence rate of diabetes has been increasing every year in nearly all nations and regions.The traditional control of diabetes using transdermal insulin delivery by metal needles is generally associated with pain...The incidence rate of diabetes has been increasing every year in nearly all nations and regions.The traditional control of diabetes using transdermal insulin delivery by metal needles is generally associated with pain and potential infections.While microneedle arrays(MAs)have emerged as painless delivery techniques,the integration of MA systems with electronic devices to precisely control drug delivery has rarely been realized.In this study,we developed an iontophoresis-microneedle array patch(IMAP)powered by a portable smartphone for the active and controllable transdermal delivery of insulin.The IMAP in situ integrates iontophoresis and charged nanovesicles into one patch,achieving a one-step drug administration strategy of“penetration,diffusion and iontophoresis”.The MA of the IMAP is first pressed on the skin to create microholes and then is retracted,followed by the iontophoresis delivery of insulin-loaded nanovesicles through these microholes in an electrically controlled manner.This method has synergistically and remarkably enhanced controlled insulin delivery.The amount of insulin can be effectively regulated by the IMAP by applying different current intensities.This in vivo study has demonstrated that the IMAP effectively delivers insulin and produces robust hypoglycemic effects in a type-1 diabetic rat model,with more advanced controllability and efficiency than delivery by a pristine microneedle or iontophoresis.The IMAP system shows high potential for diabetes therapy and the capacity to provide active as well as long-term glycemic regulation without medical staff care.展开更多
.Constructions of synthetic lattices in modulated ring resonators attract growing attention to interesting physics beyond the geometric dimensionality,where complicated connectivities between resonant frequency modes ....Constructions of synthetic lattices in modulated ring resonators attract growing attention to interesting physics beyond the geometric dimensionality,where complicated connectivities between resonant frequency modes are explored in many theoretical proposals.We implement experimental demonstration of generating a stub lattice along the frequency axis of light,in two coupled ring resonators of different lengths,with the longer one dynamically modulated.Such a synthetic photonic structure intrinsically exhibits the physics of flat band.We show that the time-resolved band structure read-out from the drop-port output of the excited ring is the intensity projection of the band structure onto a specific resonant mode in the synthetic momentum space,where gapped flat band,mode localization effect,and flat-to-nonflat band transition are observed in experiments and verified by simulations.This work provides evidence for constructing a synthetic stub lattice using two different rings,which,hence,makes a solid step toward experimentally constructing complicated lattices in multiple rings associated with synthetic frequency dimensions.展开更多
基金supported by the Shandong Province Traditional Chinese Medicine Science and Technology Project (M-2022012)。
文摘Background:Traditional Chinese medicine(TCM)is commonly used for the diagnosis and treatment of insomnia,with tongue diagnosis being particularly important.The aim of our study was to develop and validate a novel tongue imaging-based radiomics(TIR)method for accurately diagnosing insomnia severity.Methods:This two-center analysis prospectively enrolled 399 patients who underwent tongue imaging between July and October 2021 and divided them into primary and validation cohorts by study center.Here,we referred to the Insomnia Severity Index(ISI)standard and the degree of insomnia was evaluated as absent,subthreshold,moderate,or severe.For developed the TIR diagnostic tool,a U-Net algorithm was used to segment tongue images.Subsequently,seven imaging features were selected from the extracted high-throughout radiomics features using the least absolute shrinkage and selection operator algorithm.Then,the final radiomics model was developed in the primary cohort and tested in the independent validation cohort.Finally,we assessed and compared the diagnostic performance differences between TCM tongue diagnosis and our TIR diagnostic tool with the ISI gold standard.The confusion matrix was calculated to evaluate the diagnostic performance.Results:Seven tongue imaging features were selected to build the TIR tool,with showing good correlations with the insomnia degree.The TIR method had an accuracy of 0.798,a macro-average sensitivity of 0.78,a macro-average specificity of 0.906,a weighted-average sensitivity of 0.798,and a weighted specificity of 0.916,showing a significantly better performance compared to the average performance of three experienced TCM physicians(mean accuracy of 0.458,P<0.01).Conclusions:The preliminary study demonstrates the potential application of TIR in the diagnosis of insomnia degree and measurement of sleep health.The integration of quantitative imaging analysis and machine learning algorithms holds promise for advancing both of TCM and precision sleep medicine.
基金Research Result of the Chongqing University of Science and Technology Graduate Innovation Program Project“Research on the Development of Senior Study Travel Products in Chongqing Based on the Enhancement of Happiness”(Project No.YKJCX2320903)。
文摘Senior study travel,as an emerging form of tourism,combines the dual characteristics of educational learning and leisure travel.It not only meets the elderly’s desire for spiritual and cultural life and self-fulfillment but also promotes the construction of a healthy aging society.This study comprehensively uses methods such as literature analysis,interviews,and case studies to analyze the current status and existing problems of the senior study travel market.Based on the 7Ps service marketing model,it explores service marketing strategies for the senior study travel market,aiming to provide reference and guidance for related tourism enterprises to supply more attractive senior study travel services.
基金supported in part by the High Energy Photon Source Test Facility and the Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences
文摘A 3W1 superconducting wiggler(SCW)with the pole gap of 68 mm was successfully tested and installed in a BEPC II storage ring in November,2019.The goal of zero liquid helium consumption was achieved,and the cryogenic system exhibited a 12%residual cooling capacity(approximately 0.69 W@4.2 K).The 3W1-SCW was set to operate at 2.49 T and has been operating for more than seven months.Three instances of magnet quenching occurred during the normal operation.The evaporated helium gas can be recycled to the helium gas recycling system when the pressure in the helium tank is higher than the parameter value(the setpoint of the pressure value is 1.2 bara).The cryogenic system can be recovered within 4 h if sufficient liquid helium is available to inject into the cryostat.
文摘In order to achieve the optimized design of a cased telescoped ammunition(CTA) interior ballistic design,a genetic algorithm was introduced into the optimal design of CTA interior ballistics with coupling the CTA interior ballistic model. Aiming at the interior ballistic characteristics of a CTA gun, the goal of CTA interior ballistic design is to obtain a projectile velocity as large as possible. The optimal design of CTA interior ballistic is carried out using a genetic algorithm by setting peak pressure, changing the chamber volume and gun powder charge density. A numerical simulation of interior ballistics based on a 35 mm CTA firing experimental scheme was conducted and then the genetic algorithm was used for numerical optimization. The projectile muzzle velocity of the optimized scheme is increased from 1168 m/s for the initial experimental scheme to 1182 m/s. Then four optimization schemes were obtained with several independent optimization processes. The schemes were compared with each other and the difference between these schemes is small. The peak pressure and muzzle velocity of these schemes are almost the same. The result shows that the genetic algorithm is effective in the optimal design of the CTA interior ballistics. This work will be lay the foundation for further CTA interior ballistic design.
文摘The Accelerator Driven Sub-critical(ADS)system is a strategic plan to solve the nuclear waste problem for nuclear power plants in China.High-energy particle accelerators and colliders contain long strings of superconducting devices,superconducting radio frequency cavities,and magnets,which may require cooling by 2 K superfluid helium(HeliumⅡ).2 K superfluid helium cryogenic system has become a research hot spot in the field of superconducting accelerators.In this study,the ADS Injector-I 2 K cryogenic system is examined in detail.The cryogenic system scheme design,key equipment,and technology design,such as the 2 K Joule–Thomson(J–T)heat exchanger and cryomodules CM1+CM2 design,are examined,in addition to the commissioning and operation of the cryogenic system.The ADS Injector-I 2 K cryogenic system is the first 100 W superfluid helium system designed and built independently in China.The ADS proton beam reached 10 Me V at 10 m A in July 2016 and 10 Me V at 2 m A in continuous mode in January 2017 and has been operated reliably for over 15,000 h,proving that the design of ADS Injector-I 2 K cryogenic system,the key equipment,and technology research are reasonable,reliable,and meet the requirements.The research into key technologies provides valuable engineering experience that can be helpful for future projects such as CI-ADS(China Initiative Accelerator-Driven System),SHINE(Shanghai High Repetition Rate XFEL and Extreme Light Facility),PAPS(Platform of Advanced Photon Source Technology),and CEPC(Circular Electron-Positron Collider),thereby developing national expertise in the field of superfluid helium cryogenic systems.
基金supported by the High Energy Photon Source Test Facility(HEPS-TF)project。
文摘One of the most important devices for the High Energy Photon Source Test Facility project,the 2.6 T 32-pole 3W1 superconducting wiggler,was designed by the Institute of High Energy Physics(IHEP);its magnetic gap is 68 mm,and its storage energy is 286 kJ.It will be installed at the storage ring of the Beijing Electron Positron Collider Upgrade Project at the IHEP to replace the old permanent wiggler.The primary purpose of the cryostat is to create a safe and reliable system and realize long-term operation with zero liquid helium consumption.To maintain liquid helium temperature,four identical two-stage cryocoolers are placed symmetrically at the wiggler ends.The cryostat has only one 60 K thermal shield,which is used to reduce the heat load to the liquid helium vessel.The cryostat has several novel features,including a suspension system with little heat leakage that is self-centered during cooling of the cryostat,a special copper liner and high-efficiency condensers,three pairs of binary current leads,and three-level safety design.The cryogenic system has been cooled three times,and the residual cooling capacity is approximately 0.41 W at 4.2 K without current.
基金the financial support provided by the National Natural Science Foundation of China(No.51176076)
文摘A complex multiple flame structure is formed during the combustion of AP/HTPB base bleed propellant.The AP monopropellant flame is concentrated in a thin zone above the burning surface of AP crystal to maintain self-sustained decomposition.Due to the low temperature near the burning surface,the diffusion between the decomposition products of AP and the pyrolysis products of HTPB occurs,and a partly pre-mixed diffusion flame structure-leading edge flame(LEF)is formed.The effects of pressure,chemical reaction rate and AP particle size on diffusion flame structure in the range from 20 atm to 100 atm are discussed.The Peclet number increases from 6.64 at 20 atm to 21.91 at 100 atm when AP particle size is 140 mm.The high temperature zone is blown away from the burning surface because the convective transport rate increases with the increase in Peclet number.The chemical reaction rate is enhanced and the diffusion mixing is inhibited as Damkohler number increases.The chemical heat release is more concentrated and the chemical reaction zone becomes narrow when Damkohler number changes from 330 at20 atm to 4700 at 100 atm.When AP particle diameter is decreased to 60 mm,the diffusion time scale is reduced due to the reduced diffusion length scale.So the diffusion mixing is enhanced and a more pre-mixed flame is formed.The burning rate increases because the more pre-mixed heat release increases the heat feedback to the HTPB binder.
文摘A 16-pole superconducting multipole wiggler with a large gap of 68 mm was designed and fabricated to serve as a multipole wiggler for HEPS-TF.The wiggler consists of 16 pairs of NbTi superconducting coils with a period length of 170 mm,and its maximum peak field is 2.6 Tesla.In magnet design,magnet poles were optimized.Furthermore,the Lorentz force on the coils and electromagnetic force between the upper and lower halves were computed and analyzed along with the stored energy and inductance at different currents.To enhance the critical current of the magnet coil,all the pole coils selected for the magnet exhibited excellent performance,and appropriate prestress derived from the coil force analysis was applied to the pole coils during magnet assembly.The entire magnet structure was immersed in 4.2-K liquid helium in the cryostat cooled solely by four two-stage cryocoolers,and the performance test of the superconducting wiggler was appropriately completed.Based on the measured results,the first and second field integrals on the axis of the superconducting wiggler were significantly improved at different field levels after the compensation of the corrector coils.Subsequently,the wiggler was successfully installed in the storage ring of BEPCII operation with beams.
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金supported by National Natural Science Foundation of China(12104297,12122407,11974245,11825401,12192252,12204304)National Key Research and Development Program of China(2021YFA1400900)+1 种基金Shanghai Municipal Science and Technology Major Project(2019SHZDZX01-Zx06)the Innovation Program for Quantum Science and Technology(2021ZD0302000)。
文摘Measuring topological invariants is an essential task in characterizing topological phases of matter.They are usually obtained from the number of edge states due to the bulk-edge correspondence or from interference since they are integrals of the geometric phases in the energy band.It is commonly believed that the bulk band structures could not be directly used to obtain the topological invariants.Here,we implement the experimental extraction of Zak phase from the bulk band structures of a Su-Schrieffer-Heeger(SSH)model in the synthetic frequency dimension.Such synthetic SSH lattices are constructed in the frequency axis of light,by controlling the coupling strengths between the symmetric and antisymmetric supermodes of two bichromatically driven rings.We measure the transmission spectra and obtain the projection of the time-resolved band structure on lattice sites,where a strong contrast between the non-trivial and trivial topological phases is observed.The topological Zak phase is naturally encoded in the bulk band structures of the synthetic SSH lattices,which can hence be experimentally extracted from the transmission spectra in a fiber-based modulated ring platform using a laser with telecom wavelength.Our method of extracting topological phases from the bulk band structure can be further extended to characterize topological invariants in higher dimensions,while the exhibited trivial and non-trivial transmission spectra from the topological transition may find future applications in optical communications.
基金supported by the National Natural Science Foundation of China(Project No.51975597 and 52175446)the Natural Science Foundation of Guangdong Province(Project Nos.2022B1515020011 and 2021A1515011740)+1 种基金the Shenzhen Science and Technology Program(Project No.JCYJ20220818102201003)the Foundation of Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument(Project No.2020B1212060077).
文摘COVID-19 has seriously threatened public health,and transdermal vaccination is an effective way to prevent pathogen infection.Microneedles(MNs)can damage the stratum corneum to allow passive diffusion of vaccine macromolecules,but the delivery effciency is low,while iontophoresis can actively promote transdermal delivery but fails to transport vaccine macromolecules due to the barrier of the stratum corneum.Herein,we developed a wearable iontophoresis-driven MN patch and its iontophoresis-driven device for active and effcient transdermal vaccine macromolecule delivery.Polyacrylamide/chitosan hydrogels with good biocompatibility,excellent conductivity,high elasticity,and a large loading capacity were prepared as the key component for vaccine storage and active iontophoresis.The transdermal vaccine delivery strategy of the iontophoresis-driven MN patch is“press and poke,iontophoresis-driven delivery,and immune response”.We demonstrated that the synergistic effect of MN puncture and iontophoresis significantly promoted transdermal vaccine delivery effciency.In vitro experiments showed that the amount of ovalbumin delivered transdermally using the iontophoresis-driven MN patch could be controlled by the iontophoresis current.In vivo immunization studies in BALB/c mice demonstrated that transdermal inoculation of ovalbumin using an iontophoresis-driven MN patch induced an effective immune response that was even stronger than that of traditional intramuscular injection.Moreover,there was little concern about the biosafety of the iontophoresis-driven MN patch.This delivery system has a low cost,is user-friendly,and displays active delivery,showing great potential for vaccine self-administration at home.
文摘In order to study Brassica napus fatty acid （FA） metabolism and relevant regulatory networks, a systematic identification of fatty acid （FA） biosynthesis-related genes was conducted. Following gene identification, gene expression profiles during B. napus seed development and FA metabolism were performed by cDNA chip hybridization （〉8000 EST clones from seed）. The results showed that FA biosynthesis and regulation, and carbon flux, were conserved between B. napus and Arabidopsis. However, a more critical role of starch metabolism was detected for B. napus seed FA metabolism and storage-component accumulation when compared with Arabidopsis. In addition, a crucial stage for the transition of seed-to-sink tissue was 17-21 d after flowering （DAF）, whereas FA biosynthesis-related genes were highly expressed pri- marily at 21 DAF. Hormone （auxin and jasmonate） signaling is found to be important for FA metabolism. This study helps to reveal the global regulatory network of FA metabolism in developing B. napus seeds.
文摘Purpose The accelerator-driven subcritical system(ADS)is the internationally recognized key technology of nuclear waste problem treatment,of which superconducting proton linac is an important part.With the support of the strategic science and technology pilot project of the Chinese Academy of Sciences,the Institute of High Energy Physics of the Chinese Academy of Sciences took the lead in the research of 325 MHz superconducting proton linac,which is called ADS Injector I.The superconducting accelerator part of ADS Injector I mainly consists of 14 spoke-type superconducting cavities withβ0.12.At the same time,the research work of various cavities with differentβvalues and different frequencies is also carried out to lay the technical and technological foundation for ADS main accelerator.The only way to determine whether the superconducting cavity can reach the design target and whether it can be installed into the cryostat is the vertical test at cryogenic.As the only way to test the microwave performance of the superconducting cavity at low temperature,the vertical test can accurately test the acceleration gradient Eacc and the corresponding quality factor Q0 of the superconducting cavity.The design and construction of the superconducting cavity vertical test facility is based on the practical needs of the pilot project and the long-term development of the superconducting accelerator.Methods This paper mainly introduces the design and construction of the cryogenic vertical test system for the superconducting cavity of ADS Injector I,including the system scheme design,process design,heat load analysis,2 K superfluid helium obtaining method,system commissioning and operation,etc.Results and Conclusion The static heat leakage at 2 K of the 2 K superfluid helium vertical test system of ADS Injector I is 1.624W,which has reached the international advanced level.The 2 K superfluid helium vertical test system of ADS Injector I after constructed not only meets the test requirements of ADS pilot project,but also conducts 4 K and 2 K vertical tests for other different types of superconducting cavities and relevant cryogenic experiments.
基金This research is financially supported by the National Natural Science Foundation of China(Grant Nos.51575543,51975597,61771498,61901535,51805556,and 31900954)the Natural Science Foundation of Guangdong Province(Grant No.2019A1515011011 and 2018A030313698)+7 种基金the General Program of Shenzhen Innovation Funding(Grant No.JCYJ20170818164246179)the Special Support Plan for High Level Talents in Guangdong Province(Grant No.2017TQ04X674)The authors also would like to acknowledge financial support from the National Natural Science Foundation of China(Grant Nos.61901535,31900954,81970778)Guangdong Province Key Area R&D Program(Grant No.2018B030332001)Natural Science Foundation of Guangdong Province(2019A1515012087,2020A1515010665)Science and Technology Program of Guangzhou,China(Grant No.201803010097,201907010038)This work is also supported by the Open Research Fund of State Key Laboratory of Ophthalmology,Sun Yat-sen University(Grant No.303060202400358)the Youth Teacher Training Program of Sun Yat-Sen University(Grant No.20lgpy47,18lgpy18,and 20lgzd14).
文摘The incidence rate of diabetes has been increasing every year in nearly all nations and regions.The traditional control of diabetes using transdermal insulin delivery by metal needles is generally associated with pain and potential infections.While microneedle arrays(MAs)have emerged as painless delivery techniques,the integration of MA systems with electronic devices to precisely control drug delivery has rarely been realized.In this study,we developed an iontophoresis-microneedle array patch(IMAP)powered by a portable smartphone for the active and controllable transdermal delivery of insulin.The IMAP in situ integrates iontophoresis and charged nanovesicles into one patch,achieving a one-step drug administration strategy of“penetration,diffusion and iontophoresis”.The MA of the IMAP is first pressed on the skin to create microholes and then is retracted,followed by the iontophoresis delivery of insulin-loaded nanovesicles through these microholes in an electrically controlled manner.This method has synergistically and remarkably enhanced controlled insulin delivery.The amount of insulin can be effectively regulated by the IMAP by applying different current intensities.This in vivo study has demonstrated that the IMAP effectively delivers insulin and produces robust hypoglycemic effects in a type-1 diabetic rat model,with more advanced controllability and efficiency than delivery by a pristine microneedle or iontophoresis.The IMAP system shows high potential for diabetes therapy and the capacity to provide active as well as long-term glycemic regulation without medical staff care.
基金National Natural Science Foundation of China(12104297,12122407,and 11974245)National Key R&D Program of China(2017YFA0303701)+3 种基金Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Natural Science Foundation of Shanghai(19ZR1475700)China Postdoctoral Science Foundation(2020M671090)L.Y.acknowledges support from the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.X.C.also acknowledges the support from Shandong Quancheng Scholarship(00242019024).
文摘.Constructions of synthetic lattices in modulated ring resonators attract growing attention to interesting physics beyond the geometric dimensionality,where complicated connectivities between resonant frequency modes are explored in many theoretical proposals.We implement experimental demonstration of generating a stub lattice along the frequency axis of light,in two coupled ring resonators of different lengths,with the longer one dynamically modulated.Such a synthetic photonic structure intrinsically exhibits the physics of flat band.We show that the time-resolved band structure read-out from the drop-port output of the excited ring is the intensity projection of the band structure onto a specific resonant mode in the synthetic momentum space,where gapped flat band,mode localization effect,and flat-to-nonflat band transition are observed in experiments and verified by simulations.This work provides evidence for constructing a synthetic stub lattice using two different rings,which,hence,makes a solid step toward experimentally constructing complicated lattices in multiple rings associated with synthetic frequency dimensions.
