As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray as...As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.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
Na_(0.5)Bi_(0.5)TiO_(3)(NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric properties.However,their ...Na_(0.5)Bi_(0.5)TiO_(3)(NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric properties.However,their energy storage performance still needs to be further improved to satisfy the increasing demand.Herein,we report a novel 0.90(Na_(0.5)Bi_(0.5))0.7Sr_(0.3)TiO_(3-0.10)Bi(Ni_(0.5)Sn_(0.5))O_(3)(0.90NBST-0.10BNS)ceramic with significantly improved energy density(5.0 J cm3),enhanced recoverable energy density(4.18 J cm^(3))and high energy efficiency(83.64%)through the incorporation of Bi(Ni0.5Sn0.5)O3(BNS),due to the increased breakdown strength and the relaxation ferroelectric(RFE)properties.The first-order reversal curve(FORC)measurements confirm that the addition of BNS improves RFE properties by breaking the order of long-range ferroelectricity.The 0.90NBST-0.10BNS ceramic also possesses an outstanding temperature and frequency stability of energy storage properties in the range of 20C e140C and 1 Hze100 Hz,respectively.More importantly,the discharge properties characterized by a preeminent power density(36.19 MW cm^(3)),transient energy release times(144.2 ns),and high discharge energy density(1.16 J cm3)also synchronously observed in 0.90NBST-0.10BNS ceramic.These results show that the 0.90NBST-0.10BNS ceramic with outstanding comprehensive performances is a promising energy storage ceramic candidate for capacitors in high power systems.展开更多
由于缺乏先进的固体电解质界面相,水系锌电池的循环寿命受到锌金属负极副反应和枝晶等问题的严重制约.本文介绍了一种由两性分子(APMs)电解液添加剂构建而成的自组装电极-电解质界面相(AEEI).作为一个示范,这里选取聚乙烯吡咯烷酮(PVP)...由于缺乏先进的固体电解质界面相,水系锌电池的循环寿命受到锌金属负极副反应和枝晶等问题的严重制约.本文介绍了一种由两性分子(APMs)电解液添加剂构建而成的自组装电极-电解质界面相(AEEI).作为一个示范,这里选取聚乙烯吡咯烷酮(PVP)用做APMs,因为它的羰基氧原子与芳香性的吡咯环共轭,从而具有较强的电子给体性质.X射线光电子能谱和傅里叶变换红外光谱分析表明,AEEI的形成和稳定是由APMs的羰基氧原子同时与锌金属和锌离子相互作用推动的.所形成的AEEI主要由富含锌离子的APMs致密层状胶束构成.在电解质中保持APMs的含量在临界聚集浓度(~0.1%)以上,可以保证AEEI的固有稳定性,避免裂纹形成或脱落等问题.得益于其抑制水分解副反应和不利的二维锌扩散的能力,在AEEI的作用下实现了无枝晶的锌沉积.在1 M Zn(OTf)_(2)添加1%PVP的电解液中,形成的AEEI保证了锌对称电池具有超过2000小时的长循环寿命,Zn||Ti电池500个循环后库仑效率高于99.2%,以及V_(2)O_(5)||Zn全电池500个循环后容量的高保持率(达76%).展开更多
Dielectrics used for energy storage are highly desired for power electronics and pulse power applications and the polymer capacitors are the main commercial ones available.The development of flexible electronics and w...Dielectrics used for energy storage are highly desired for power electronics and pulse power applications and the polymer capacitors are the main commercial ones available.The development of flexible electronics and wearable devices require the relative materials being flexible.Besides,high temperature resistance is also desired because of the rising demand for high power devices and large electricity under elevated temperature.The polymer dielectrics for polymer capacitors are flexible but with relatively low working temperature normally less than 100℃.Therefore,fabricating a dielectric material to satisfy the flexibility and high working temperature simultaneously is still a great challenge.Here we propose one solution by demonstrating a hand-exfoliated fluorophlogopite film with micrometer scale thickness.Among which,the mica film with a thickness of around 10μm(Mica-10)exhibits the inorganic-like temperature stability even polymer-like flexibility.From 25℃to 200℃,Mica-10 has an energy density of around 11.27 J/cm^(3)with a variation within 2%,accompanied by a charge-discharge efficiency of around 95%at an electric field of 500 MV/m.Meanwhile,the thin thickness makes Mica-10 flexible,enabling its excellent flexibility and durability.This work revives the traditional material,mica,providing a way for high-temperature energy storage applications.展开更多
The internal pressure of the process was studied theoretically and experimentally. The external load character and internal stress character of tube hydroforming were discussed first. Then, according to the characters...The internal pressure of the process was studied theoretically and experimentally. The external load character and internal stress character of tube hydroforming were discussed first. Then, according to the characters, the function and classification of internal pressure were presented in general. Base on the stress analysis, its effect on the yield criterion and calculation formula were also researched and derived. To verify the correction of the theoretical analysis and derived formula, experiments with different internal pressures were carried out and the result was compared and discussed. It demonstrates that internal pressure plays an important role in tube hydroforming and theory and formula discussed and derived by this paper are feasible in practice.展开更多
Successful vaccines induce specific immune responses and protect against various viral and bacterial infections. Noninactivated vaccines, especially viral vector vaccines such as adenovirus and poxvirus vaccines, domi...Successful vaccines induce specific immune responses and protect against various viral and bacterial infections. Noninactivated vaccines, especially viral vector vaccines such as adenovirus and poxvirus vaccines, dominate the vaccine market because their viral particles are able to replicate and proliferate in vivo and produce lasting immunity in a manner similar to natural infection. One challenge of human and livestock vaccination is vaccine stability related to the antigenicity and infectivity. Freeze-drying is the typical method to maintain virus vaccine stability, while cold chain transportation is required for temperatures about 2 °C–8 °C. The financial and technological resource requirements hinder vaccine distribution in underdeveloped areas. In this study, we developed a freeze-drying formula consisting of bovine serum albumin(BSA), L-glutamic acid(L-Glu), polyethylene glycol(PEG), and dextran(DEX) to improve the thermal stability and activity of viral vaccines, including vaccinia recombinant vaccine(rTTV-OVA) and adenovirus vaccine(Ad5-ENV). We compared a panel of five different formulations(PEG: DEX: BSA: L-GLU = 50:9:0:0(#1), 50:5:4:0(#2), 50:10:9:0(#3),50:0:0:9(#4), and 50:1:0:8(#5), respectively) and optimized the freeze-drying formula for rTTV-OVA and Ad5-ENV. We found that the freeze-drying formulations #2 and #3 could maintain rTTV-OVA infectivity at temperatures of 4 °C and25 °C and that r TTV-OVA immunogenicity was retained during lyophilization. However, formulations #4 and #5 maintained Ad5-ENV infectivity under the same conditions, and Ad5-ENV immunogenicity had maximum retention with freeze-drying formulation #4. In summary, we developed new freeze-drying formulations that increased virus vaccine storage times and retained immunogenicity at an ambient temperature.展开更多
基金project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)support from the National Key Research and Development Program of China(Grant No.2016YFA0400800)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA04010202,XDA04010300,and XDB23040400)the National Natural Science Foundation of China(Grant Nos.U1838201,and U1838102).
文摘As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.
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The authors sincerely thank the support from the National Natural Science Foundation of China(Grant No.51572159)the Shaanxi Science&Technology Co-ordination&Innovation Project of China(Grant No.2017TSCXL-GY-08-05)the Science Fund for Distinguished Young Scholars of Shaanxi Province(Grant No.2018JC-029).
文摘Na_(0.5)Bi_(0.5)TiO_(3)(NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric properties.However,their energy storage performance still needs to be further improved to satisfy the increasing demand.Herein,we report a novel 0.90(Na_(0.5)Bi_(0.5))0.7Sr_(0.3)TiO_(3-0.10)Bi(Ni_(0.5)Sn_(0.5))O_(3)(0.90NBST-0.10BNS)ceramic with significantly improved energy density(5.0 J cm3),enhanced recoverable energy density(4.18 J cm^(3))and high energy efficiency(83.64%)through the incorporation of Bi(Ni0.5Sn0.5)O3(BNS),due to the increased breakdown strength and the relaxation ferroelectric(RFE)properties.The first-order reversal curve(FORC)measurements confirm that the addition of BNS improves RFE properties by breaking the order of long-range ferroelectricity.The 0.90NBST-0.10BNS ceramic also possesses an outstanding temperature and frequency stability of energy storage properties in the range of 20C e140C and 1 Hze100 Hz,respectively.More importantly,the discharge properties characterized by a preeminent power density(36.19 MW cm^(3)),transient energy release times(144.2 ns),and high discharge energy density(1.16 J cm3)also synchronously observed in 0.90NBST-0.10BNS ceramic.These results show that the 0.90NBST-0.10BNS ceramic with outstanding comprehensive performances is a promising energy storage ceramic candidate for capacitors in high power systems.
基金supported by the National Natural Science Foundation of China(52271222,51902301 and 22379096)the Natural Science Foundation of Zhejiang Province(LY21E020006)Shanghai Science and Technology Commission(21010503100 and 23DZ1202500)。
文摘由于缺乏先进的固体电解质界面相,水系锌电池的循环寿命受到锌金属负极副反应和枝晶等问题的严重制约.本文介绍了一种由两性分子(APMs)电解液添加剂构建而成的自组装电极-电解质界面相(AEEI).作为一个示范,这里选取聚乙烯吡咯烷酮(PVP)用做APMs,因为它的羰基氧原子与芳香性的吡咯环共轭,从而具有较强的电子给体性质.X射线光电子能谱和傅里叶变换红外光谱分析表明,AEEI的形成和稳定是由APMs的羰基氧原子同时与锌金属和锌离子相互作用推动的.所形成的AEEI主要由富含锌离子的APMs致密层状胶束构成.在电解质中保持APMs的含量在临界聚集浓度(~0.1%)以上,可以保证AEEI的固有稳定性,避免裂纹形成或脱落等问题.得益于其抑制水分解副反应和不利的二维锌扩散的能力,在AEEI的作用下实现了无枝晶的锌沉积.在1 M Zn(OTf)_(2)添加1%PVP的电解液中,形成的AEEI保证了锌对称电池具有超过2000小时的长循环寿命,Zn||Ti电池500个循环后库仑效率高于99.2%,以及V_(2)O_(5)||Zn全电池500个循环后容量的高保持率(达76%).
基金The work was supported by the National 973 projects of China(No.2015CB654603)the National Natural Science Foundation of China(No.61471290,61631166004).
文摘Dielectrics used for energy storage are highly desired for power electronics and pulse power applications and the polymer capacitors are the main commercial ones available.The development of flexible electronics and wearable devices require the relative materials being flexible.Besides,high temperature resistance is also desired because of the rising demand for high power devices and large electricity under elevated temperature.The polymer dielectrics for polymer capacitors are flexible but with relatively low working temperature normally less than 100℃.Therefore,fabricating a dielectric material to satisfy the flexibility and high working temperature simultaneously is still a great challenge.Here we propose one solution by demonstrating a hand-exfoliated fluorophlogopite film with micrometer scale thickness.Among which,the mica film with a thickness of around 10μm(Mica-10)exhibits the inorganic-like temperature stability even polymer-like flexibility.From 25℃to 200℃,Mica-10 has an energy density of around 11.27 J/cm^(3)with a variation within 2%,accompanied by a charge-discharge efficiency of around 95%at an electric field of 500 MV/m.Meanwhile,the thin thickness makes Mica-10 flexible,enabling its excellent flexibility and durability.This work revives the traditional material,mica,providing a way for high-temperature energy storage applications.
基金This work is supported by the National Natural Science Foundation under grant No.59975021,which was gratefully acknowledged.At the same time,the author also thanks Prof.P.Zeng of Tsinghua University for his kind assistance which is also indispensble in the accomplishment of this paper.
文摘The internal pressure of the process was studied theoretically and experimentally. The external load character and internal stress character of tube hydroforming were discussed first. Then, according to the characters, the function and classification of internal pressure were presented in general. Base on the stress analysis, its effect on the yield criterion and calculation formula were also researched and derived. To verify the correction of the theoretical analysis and derived formula, experiments with different internal pressures were carried out and the result was compared and discussed. It demonstrates that internal pressure plays an important role in tube hydroforming and theory and formula discussed and derived by this paper are feasible in practice.
基金supported by the National Key R&D Program (2016YFC1303402)the National 13th Five-Year Grand Programon Key Infectious Disease Control (2018ZX10301403, 2017ZX10202102-006)the Intramural Funding from Shanghai Public Health Clinical Center。
文摘Successful vaccines induce specific immune responses and protect against various viral and bacterial infections. Noninactivated vaccines, especially viral vector vaccines such as adenovirus and poxvirus vaccines, dominate the vaccine market because their viral particles are able to replicate and proliferate in vivo and produce lasting immunity in a manner similar to natural infection. One challenge of human and livestock vaccination is vaccine stability related to the antigenicity and infectivity. Freeze-drying is the typical method to maintain virus vaccine stability, while cold chain transportation is required for temperatures about 2 °C–8 °C. The financial and technological resource requirements hinder vaccine distribution in underdeveloped areas. In this study, we developed a freeze-drying formula consisting of bovine serum albumin(BSA), L-glutamic acid(L-Glu), polyethylene glycol(PEG), and dextran(DEX) to improve the thermal stability and activity of viral vaccines, including vaccinia recombinant vaccine(rTTV-OVA) and adenovirus vaccine(Ad5-ENV). We compared a panel of five different formulations(PEG: DEX: BSA: L-GLU = 50:9:0:0(#1), 50:5:4:0(#2), 50:10:9:0(#3),50:0:0:9(#4), and 50:1:0:8(#5), respectively) and optimized the freeze-drying formula for rTTV-OVA and Ad5-ENV. We found that the freeze-drying formulations #2 and #3 could maintain rTTV-OVA infectivity at temperatures of 4 °C and25 °C and that r TTV-OVA immunogenicity was retained during lyophilization. However, formulations #4 and #5 maintained Ad5-ENV infectivity under the same conditions, and Ad5-ENV immunogenicity had maximum retention with freeze-drying formulation #4. In summary, we developed new freeze-drying formulations that increased virus vaccine storage times and retained immunogenicity at an ambient temperature.
