Grid-forming(GFM)control is a key technique for power systems with high penetration of converter-interfaced generation.However,its application to photovoltaic(PV)systems faces challenges related to DC voltage transien...Grid-forming(GFM)control is a key technique for power systems with high penetration of converter-interfaced generation.However,its application to photovoltaic(PV)systems faces challenges related to DC voltage transient stability.This paper investigates a common countermeasure involving a PI-based DC voltage controller for GFM-PV systems,revealing that their small-signal stability is sensitive to parameter tuning.The study develops a generalized DC voltage-dominated 2nd-order GFM model and successfully conducts complex torque analysis,showing that this approach can be effectively extended to other dynamics governed by DC voltage-dominated GFM systems.Subsequently,the paper establishes a stability criterion for GFM-PV systems and proposes a parameter tuning method for DC voltage controllers that incorporates damping margin considerations.The performance of the tuned single-machine-infinite-bus GFM-PV system is validated on the RT-LAB real-time simulation platform under scenarios involving solar irradiance fluctuations and grid frequency disturbances.The proposed method proves effective in ensuring the stability of the GFM-PV system,with robust theoretical support.展开更多
We report the SrII optical lattice clock at the National Time Service Center(NTSC).In this system,a blackbody radiation shield with movable lattice mitigates blackbody radiation shifts through active temperature contr...We report the SrII optical lattice clock at the National Time Service Center(NTSC).In this system,a blackbody radiation shield with movable lattice mitigates blackbody radiation shifts through active temperature control.A shallow optical lattice with minimal tunneling minimizes AC Stark shifts.Phase-locked counter-propagating lattice beams and conductive vacuum viewports further reduce systematic uncertainties and a novel initial-state preparation method simplifies the system.Clock transition spectra achieve a linewidth of 2.5 Hz with a 400 ms clock pulse,and self-comparison stability reaches 5.1×10^(-16)at 1 s.These advancements give this clock the potential to be a critical platform for realizing outstanding systematic uncertainties in the future.展开更多
BACKGROUND Hepatitis D virus-hepatitis B virus(HDV-HBV)co-infection accelerates liver disease progression and increases the risk of hepatocellular carcinoma,but the immunopathogenic mechanism of its combination with a...BACKGROUND Hepatitis D virus-hepatitis B virus(HDV-HBV)co-infection accelerates liver disease progression and increases the risk of hepatocellular carcinoma,but the immunopathogenic mechanism of its combination with autoimmune hepatitis(AIH)has not been clarified.This study reveals for the first time that HDV may induce AIH through abnormalities in immunoregulation in two specific cases.This is the first report of HDV-HBV co-infected patients who did not receive interferon therapy and achieved serological conversion and histological remission by combining antiviral(entecavir)with immunosuppression(prednisone+azathioprine)therapy,providing new evidence of the mechanism of this complex disease.CASE SUMMARY A 40-year-old female developed malaise and jaundice with an alanine aminotransferase/aspartate aminotransferase>20 upper limit of normal(ULN),total bilirubin:97.20μmol/L,immunoglobulin G(IgG)47.1 g/L(>3×ULN),HDV RNA 1.6×10^(7)copies/mL and liver biopsy showed G3S4.Tenofovir alafenamide combined with prednisone and azathioprine was administered,and three months later the Child-Turcotte-Pugh class C was reduced to class B and IgG decreased to 13.62 g/L.Another 58-year-old male complained of pain in the liver area,antinuclear antibody was 1:320,IgG 22.6 g/L(>1.3×ULN),and liver biopsy showed G2S3.Entecavir was administered in combination with prednisone and azathioprine,and after 3 months,liver function returned to normal,and IgG reduced to 14.22 g/L.CONCLUSION Patients with HDV-HBV co-infection combined with AIH can achieve clinical remission following combination therapy,and the study of immunomodulatory mechanisms should be emphasized.展开更多
Coatings of marine equipment inevitably suffer from physical or chemical damage in service,together with biofouling from microbial attachment,leading to a shorter service life of them.Herein,a multi-functional corrosi...Coatings of marine equipment inevitably suffer from physical or chemical damage in service,together with biofouling from microbial attachment,leading to a shorter service life of them.Herein,a multi-functional corrosion-resistant coating with efficient photothermal self-healing and anti-biofouling per-formance was designed by using CuO/g-C_(3)N_(4)(CuO/CN)S-scheme heterojunction filler in combination with polydimethylsiloxane(PDMS)as the coating matrix for achieving the effective protection of Q235 steel.The results of the electrochemical impedance spectroscopy(EIS)experiments indicate that the CuO/CN/PDMS composite coatings possessed excellent corrosion resistance,in which the impedance ra-dius of optimal CuO/CN-1/PDMS composite coating could still remain 3.49×10^(9)Ωcm^(2)after 60 d of immersion in seawater under sunlight irradiation.Meanwhile,the as-prepared CuO/CN/PDMS compos-ite coating not only can be rapidly heated up under the Xenon lamp illumination to achieve complete self-repair of scratches within 45 min,but also exhibited excellent antimicrobial effects in the antifouling experiments.This study opens a new avenue for the development of g-C_(3)N_(4)-based multifunctional coat-ings and provides guidance for the development of the next generation of intelligent protective coatings.展开更多
This study presents an achievement of laser cooling of alkaline-earth atoms in the Chinese Space Station’s strontium(Sr)atomic space optical clock.The system’s core components,physical unit,optical unit,and electric...This study presents an achievement of laser cooling of alkaline-earth atoms in the Chinese Space Station’s strontium(Sr)atomic space optical clock.The system’s core components,physical unit,optical unit,and electrical unit,have a total volume of 306 L and a total mass of 163.8 kg.These compact and robust units can overcome mechanical vibrations and temperature fluctuations during space launch.The laser sources of the optical unit are composed of diode lasers,and the injection locking of slave lasers is automatically performed by a program.In the experiment,a blue magneto-optical trap of cold atoms was achieved,with the atom numbers estimated to be approximately(1.50±0.13)×10^(6) for 87Sr and(8.00±0.56)×10^(6) for 88Sr.This work establishes a foundation for atomic confinement and high-precision interrogation in space-based optical clocks and expands the frontiers of cold atom physics in microgravity.展开更多
Abnormal accumulation of collagen fibrils is a hallmark feature of oral submucous fibrosis(OSF).However,the precise characteristics and underlying mechanisms remain unclear,impeding the advancement of potential therap...Abnormal accumulation of collagen fibrils is a hallmark feature of oral submucous fibrosis(OSF).However,the precise characteristics and underlying mechanisms remain unclear,impeding the advancement of potential therapeutic approaches.Here,we observed that collagen Ⅰ,the main component of the extracellular matrix,first accumulated in the lamina propria and subsequently in the submucosa of OSF specimens as the disease progressed.Using RNA-seq and Immunofluorescence in OSF specimens,we screened the cartilage oligomeric matrix protein(COMP)responsible for the abnormal collagen accumulation.Genetic COMP deficiency reduced arecoline-stimulated collagen I deposition significantly in vivo.In comparison,both COMP and collagen Ⅰ were upregulated under arecoline stimulation in wild-type mice.Human oral buccal mucosal fibroblasts(hBMFs)also exhibited increased secretion of COMP and collagen I after stimulation in vitro.COMP knockdown in hBMFs downregulates arecoline-stimulated collagen Ⅰ secretion.We further demonstrated that hBMFs present heterogeneous responses to arecoline stimulation,of which COMP-positive fibroblasts secrete more collagen Ⅰ.Since COMP is a molecular bridge with Fibril-associated collagens with Interrupted Triple helices(FACIT)in the collagen network,we further screened and identified collagen XIV,a FACIT member,co-localizing with both COMP and collagen Ⅰ.Collagen XIV expression increased under arecoline stimulation in wild-type mice,whereas it was hardly expressed in the Comp^(-/-) mice,even with under stimulation.In summary,we found that COMP may mediates abnormal collagen Ⅰ deposition by functions with collagen XIV during the progression of OSF,suggesting its potential to be targeted in treating OSF.展开更多
基金supported in part by Northeast Branch of State Grid Corporation of China(52992624000W).
文摘Grid-forming(GFM)control is a key technique for power systems with high penetration of converter-interfaced generation.However,its application to photovoltaic(PV)systems faces challenges related to DC voltage transient stability.This paper investigates a common countermeasure involving a PI-based DC voltage controller for GFM-PV systems,revealing that their small-signal stability is sensitive to parameter tuning.The study develops a generalized DC voltage-dominated 2nd-order GFM model and successfully conducts complex torque analysis,showing that this approach can be effectively extended to other dynamics governed by DC voltage-dominated GFM systems.Subsequently,the paper establishes a stability criterion for GFM-PV systems and proposes a parameter tuning method for DC voltage controllers that incorporates damping margin considerations.The performance of the tuned single-machine-infinite-bus GFM-PV system is validated on the RT-LAB real-time simulation platform under scenarios involving solar irradiance fluctuations and grid frequency disturbances.The proposed method proves effective in ensuring the stability of the GFM-PV system,with robust theoretical support.
基金supported by the Innovation Pro-gram for Quantum Science and Technology(Grant Nos.2021ZD0300900 and 2021ZD0300902)the Strate-gic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB35010202)the Operation and Maintenance of Major Scientific and Technological In-frastructure of the Chinese Academy of Sciences(Grant No.2024000014).
文摘We report the SrII optical lattice clock at the National Time Service Center(NTSC).In this system,a blackbody radiation shield with movable lattice mitigates blackbody radiation shifts through active temperature control.A shallow optical lattice with minimal tunneling minimizes AC Stark shifts.Phase-locked counter-propagating lattice beams and conductive vacuum viewports further reduce systematic uncertainties and a novel initial-state preparation method simplifies the system.Clock transition spectra achieve a linewidth of 2.5 Hz with a 400 ms clock pulse,and self-comparison stability reaches 5.1×10^(-16)at 1 s.These advancements give this clock the potential to be a critical platform for realizing outstanding systematic uncertainties in the future.
基金Supported by Xinjiang“Tianshan Talents”Medical and Health High-Level Talent Training Program-Young and Middle-Aged Backbone Medical Talents.
文摘BACKGROUND Hepatitis D virus-hepatitis B virus(HDV-HBV)co-infection accelerates liver disease progression and increases the risk of hepatocellular carcinoma,but the immunopathogenic mechanism of its combination with autoimmune hepatitis(AIH)has not been clarified.This study reveals for the first time that HDV may induce AIH through abnormalities in immunoregulation in two specific cases.This is the first report of HDV-HBV co-infected patients who did not receive interferon therapy and achieved serological conversion and histological remission by combining antiviral(entecavir)with immunosuppression(prednisone+azathioprine)therapy,providing new evidence of the mechanism of this complex disease.CASE SUMMARY A 40-year-old female developed malaise and jaundice with an alanine aminotransferase/aspartate aminotransferase>20 upper limit of normal(ULN),total bilirubin:97.20μmol/L,immunoglobulin G(IgG)47.1 g/L(>3×ULN),HDV RNA 1.6×10^(7)copies/mL and liver biopsy showed G3S4.Tenofovir alafenamide combined with prednisone and azathioprine was administered,and three months later the Child-Turcotte-Pugh class C was reduced to class B and IgG decreased to 13.62 g/L.Another 58-year-old male complained of pain in the liver area,antinuclear antibody was 1:320,IgG 22.6 g/L(>1.3×ULN),and liver biopsy showed G2S3.Entecavir was administered in combination with prednisone and azathioprine,and after 3 months,liver function returned to normal,and IgG reduced to 14.22 g/L.CONCLUSION Patients with HDV-HBV co-infection combined with AIH can achieve clinical remission following combination therapy,and the study of immunomodulatory mechanisms should be emphasized.
基金supported by the National Natural Science Foundation of China(Nos.22006057 and 21906072)the China Postdoctoral Science Foundation(No.2023M743178)+2 种基金the Jiangsu Province Industry-University-Research Cooperation Project(No.BY20231482)the Open Fund of the Key Laboratory of Solar Cell electrode Materials in China Petroleum,Chemical Industry(No.2024A093)the Key Laboratory of Functional Inorganic Mate-rial Chemistry(Heilongjiang University),Ministry of Education and Postgraduate Research&Practice Innovation Program of Jiangsu Province(China)(No.SJCX24_2481).
文摘Coatings of marine equipment inevitably suffer from physical or chemical damage in service,together with biofouling from microbial attachment,leading to a shorter service life of them.Herein,a multi-functional corrosion-resistant coating with efficient photothermal self-healing and anti-biofouling per-formance was designed by using CuO/g-C_(3)N_(4)(CuO/CN)S-scheme heterojunction filler in combination with polydimethylsiloxane(PDMS)as the coating matrix for achieving the effective protection of Q235 steel.The results of the electrochemical impedance spectroscopy(EIS)experiments indicate that the CuO/CN/PDMS composite coatings possessed excellent corrosion resistance,in which the impedance ra-dius of optimal CuO/CN-1/PDMS composite coating could still remain 3.49×10^(9)Ωcm^(2)after 60 d of immersion in seawater under sunlight irradiation.Meanwhile,the as-prepared CuO/CN/PDMS compos-ite coating not only can be rapidly heated up under the Xenon lamp illumination to achieve complete self-repair of scratches within 45 min,but also exhibited excellent antimicrobial effects in the antifouling experiments.This study opens a new avenue for the development of g-C_(3)N_(4)-based multifunctional coat-ings and provides guidance for the development of the next generation of intelligent protective coatings.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB35010202)the National Natural Science Foundation of China(Grants No.62275268)。
文摘This study presents an achievement of laser cooling of alkaline-earth atoms in the Chinese Space Station’s strontium(Sr)atomic space optical clock.The system’s core components,physical unit,optical unit,and electrical unit,have a total volume of 306 L and a total mass of 163.8 kg.These compact and robust units can overcome mechanical vibrations and temperature fluctuations during space launch.The laser sources of the optical unit are composed of diode lasers,and the injection locking of slave lasers is automatically performed by a program.In the experiment,a blue magneto-optical trap of cold atoms was achieved,with the atom numbers estimated to be approximately(1.50±0.13)×10^(6) for 87Sr and(8.00±0.56)×10^(6) for 88Sr.This work establishes a foundation for atomic confinement and high-precision interrogation in space-based optical clocks and expands the frontiers of cold atom physics in microgravity.
基金supported by the National Natural Science Foundation of China grant(81974150).
文摘Abnormal accumulation of collagen fibrils is a hallmark feature of oral submucous fibrosis(OSF).However,the precise characteristics and underlying mechanisms remain unclear,impeding the advancement of potential therapeutic approaches.Here,we observed that collagen Ⅰ,the main component of the extracellular matrix,first accumulated in the lamina propria and subsequently in the submucosa of OSF specimens as the disease progressed.Using RNA-seq and Immunofluorescence in OSF specimens,we screened the cartilage oligomeric matrix protein(COMP)responsible for the abnormal collagen accumulation.Genetic COMP deficiency reduced arecoline-stimulated collagen I deposition significantly in vivo.In comparison,both COMP and collagen Ⅰ were upregulated under arecoline stimulation in wild-type mice.Human oral buccal mucosal fibroblasts(hBMFs)also exhibited increased secretion of COMP and collagen I after stimulation in vitro.COMP knockdown in hBMFs downregulates arecoline-stimulated collagen Ⅰ secretion.We further demonstrated that hBMFs present heterogeneous responses to arecoline stimulation,of which COMP-positive fibroblasts secrete more collagen Ⅰ.Since COMP is a molecular bridge with Fibril-associated collagens with Interrupted Triple helices(FACIT)in the collagen network,we further screened and identified collagen XIV,a FACIT member,co-localizing with both COMP and collagen Ⅰ.Collagen XIV expression increased under arecoline stimulation in wild-type mice,whereas it was hardly expressed in the Comp^(-/-) mice,even with under stimulation.In summary,we found that COMP may mediates abnormal collagen Ⅰ deposition by functions with collagen XIV during the progression of OSF,suggesting its potential to be targeted in treating OSF.
