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Frequency steering of spaceborne clocks based on XPNAV-1 observations

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Chinese Journal of Aeronautics 2023年第6期36卷 266-278页

作者： Mengna HAN Minglei TONG Liansheng LI Yongqiang shi Tinggao YANG Yuping GAO National Time Service Center Chinese Academy of SciencesXi'an 710600China Schoolof Astronomy and Space Science University of Chinese Academy of SciencesBejing 100049China Beijing Institute of Control Engineering Beijing 100190China

Due to high stable rotations, timing of pulsars provides a natural tool to correct the frequency deviation of spaceborne atomic clocks. Based on processing the observational data about a year of Crab pulsar given by XPNAV-1 satellite, we study the possibility of correcting the frequency deviation of spaceborne atomic clocks using pulsar timing. According to the observational data in X-ray band and the timing model parameters from radio observations, the pre-fit timing residuals with a level of 67.66 μs are obtained. By fitting the slope of the timing residuals affected by the faked frequency-biased reference clock, we estimated successfully the relative frequency deviation of the reference clock. For a satellite clock with frequency deviation of the order about 10^(-12), a calibration accuracy with relative error of about 2% can be obtained from the Crab pulsar’s data for one year.The stability of the time scale based on Crab pulsar is about 10^(-12) for an interval of one year.

关键词： Pulsar time scale Pulsar timing Atomic clock Frequency steering X-ray observation

n-Type acceptor-acceptor polymer semiconductors

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Journal of Semiconductors 2021年第10期42卷 6-8页

作者： Yongqiang shi Liming Ding College of Chemistry and Materials Science Anhui Normal UniversityWuhu 241002China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Polymer semiconductors have aroused interests from both academic and industry due to their wide applications in electronic devices,such as organic thin-film transistors(OT-FTs)[1],polymer solar cells(PSCs)[2−6],organic thermoelectrics(OTEs)[7−11],and perovskite solar cells(PVSCs)[12−14].To date,great efforts have been devoted to developing p-type poly-mer semiconductors,while the development of n-type poly-mers lags far behind.In fact,n-type polymers are essential for organic electronic devices.

关键词： semiconductors acceptor polymer

Amitriptyline inhibits NLRP3 inflammasome activation via the ASM/CE pathway in a cell model of NAFLD

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BIOCELL 2024年第5期48卷 759-769页

作者： QIN LIU CHUNYAN NIU QIANG ZHANG shiQIN SUN YUE CHEN Yongqiang shi Shengli Clinical Medical College Fujian Medical UniversityFuzhou350001China Department of Gastroenterology Nanjing Lishui People’s HospitalZhongda Hospital Lishui BranchSoutheast UniversityNanjing211200China Department of Gastroenterology Yancheng Third People’s Hospital(The Yancheng School of Clinical Medicine of Nanjing Medical University)Yancheng224000China Administrative Department of Teaching and Scientific Research Nanjing Lishui People’s HospitalZhongda Hospital Lishui BranchSoutheast UniversityNanjing211200China

Background:Nonalcoholic fatty liver disease(NAFLD)is a global health concern with the acid sphingomyelinase(ASM)/ceramide(CE)pathway and the NOD-like receptor family,pyrin domain-containing protein 3(NLRP3)inflammasome identified as pivotal players in lipid disorders and inflammation.This study explores the interaction mechanism between the ASM/CE pathway and NLRP3 in NAFLD cell models,aiming to understand the impact of amitriptyline(Ami),an ASM inhibitor,on lipid deposition and hepatocyte injury by regulating the ASM/CE-NLRP3 pathway.Methods:HepG2 and HL-7702 cells were exposed to free fatty acids(FFAs)to establish the NAFLD model.The cells were divided into 5 groups:control group,model group,Ami group,tumor necrosis factoralpha(TNF-α)group,and Ami+TNF-αgroup.Intracellular lipid droplets were visualized using Oil Red O staining,and Western blot analysis quantified ASM,NLRP3,and caspase 1 protein expression.Enzyme linked immunosorbent assay(ELISA)was measured CE and ASM levels,while qRT-PCR assessed mRNA expression.The apoptotic rate was evaluated by flow cytometry(FCM).Results:Following FFAs incubation,significant increases in ASM and CE levels were observed in HepG2 and HL-7702 cells,accompanied by elevated expression of NLRP3,and caspase 1,and IL-1β.TNF-αtreatment further amplified these indicators.Ami demonstrated a reduction in lipid deposition,suppressed ASM/CE pathway activation,downregulated NLRP3 and caspase 1 expression,and improved apoptosis.Additionally,MCC950,a selective inhibitor of the NLRP3,mitigated NLRP3,caspase 1,and IL-1βexpression,alleviating lipid deposition and apoptosis in the NAFLD cell model.Conclusion:The ASM/CE-NLRP3 pathway in NAFLD cells promotes hepatocyte steatosis,inflammation,and cell damage.Ami emerges as a promising therapeutic agent by inhibiting the ASM/CE-NLRP3 pathway,underscoring its potential as a key target for NAFLD treatment.

关键词： Nonalcoholic fatty liver disease Hepatocyte Amitriptyline ASM/CE pathway NLRP3 Nonalcoholic steatohepatitis

To enhance the performance of n-type organic thermoelectric materials

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Journal of Semiconductors 2022年第2期43卷 5-7页

作者： Xin Wang Yongqiang shi Liming Ding School of Chemistry and Materials Science Anhui Normal UniversityWuhu 241002China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Organic thermoelectric(OTE)materials that can convert waste heat to electricity have aroused interests due to their unique advantages over traditional inorganic TE materials,such as light weight,mechanical flexibility,low thermal conductivity,and solution processability[1-4].In general,TE devices require both p-type and n-type semiconductors.The p-type polymers have been extensively studied,showing rapid advances,but there are few efficient n-type TE polymers[5,6].Therefore,the development of high-performance ndoped conjugated polymers is demanded.

关键词： performance inorganic conjugated

Significant sensing performance of an all-silicon terahertz metasurface chip for Bacillus thuringiensis Cry1Ac protein

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Photonics Research 2022年第3期10卷 740-746页

作者： Zijian Cui Yue Wang Yongqiang shi yongqiang Zhu Dachi Zhang Zhiqi Hong Xuping Feng Key Laboratory of Ultrafast Photoelectric Technology and Terahertz Science in Shaanxi Xi’an University of TechnologyXi’an 710048China Key Laboratory of Engineering Dielectric and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbin 150080China College of Biosystems Engineering and Food Science Zhejiang UniversityHangzhou 310058China

The promising prospect of a terahertz metasurface in sensing and detection applications has attracted increasing attention because of its ability to overcome the classical diffraction limit and the enhancement of field intensity.In this work,a novel scheme based on an all-silicon terahertz plasmon metasurface is proposed and experimentally demonstrated to be a highly sensitive biosensor for the Bacillus thuringiensis Cry1Ac toxin.The regression coefficients between Bacillus thuringiensis protein concentrations and the spectral resonance intensity and frequency were 0.8988 and 0.9238,respectively.The resonance amplitude variation and frequency shift of the metasurface were investigated in terms of both thickness and permittivity change of the analyte,which reflected the protein residue in the actual process.Moreover,the reliability and stability of the metasurface chip were verified by time period,temperature,and humidity control.These results promise the ability of the proposed metasurface chip as a Bacillus thuringiensis protein sensor with high sensitivity and stability.In addition,this novel device strategy provides opportunities for the advancement of terahertz functional applications in the fields of biochemical sensing and detection.

关键词： stability process overcome

Cloud Storage Security Assessment Through Equilibrium Analysis

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Tsinghua Science and Technology 2019年第6期24卷 738-749页

作者： Yuzhao Wu yongqiang Lyu Yuanchun shi Institute for Interdisciplinary Information Sciences Tsinghua UniversityBeijing 100084China Research Institute of Information Technology & TNList Tsinghua UniversityBeijing 100084China State Key Laboratory of Intelligent Technology and Systems Tsinghua UniversityBeijing 100084China

With ever greater amounts of data stored in cloud servers, data security and privacy issues have become increasingly important. Public cloud storage providers are semi-trustworthy because they may not have adequate security mechanisms to protect user data from being stolen or misused. Therefore, it is crucial for cloud users to evaluate the security of cloud storage providers. However, existing security assessment methods mainly focus on external security risks without considering the trustworthiness of cloud providers. In addition, the widely used thirdparty mediators are assumed to be trusted and we are not aware of any work that considers the security of these mediators. This study fills these gaps by assessing the security of public cloud storage providers and third-party mediators through equilibrium analysis. More specifically, we conduct evaluations on a series of game models between public cloud storage providers and users to thoroughly analyze the security of different service scenarios.Using our proposed security assessment, users can determine the risk of whether their privacy data is likely to be hacked by the cloud service providers;the cloud service providers can also decide on strategies to make their services more trustworthy. An experimental study of 32 users verified our method and indicated its potential for real service improvement.

关键词： cloud storage security security assessment equilibrium analysis

Design of the solar X-ray detector for the Macau Science Satellite-1B

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Earth and Planetary Physics 2023年第1期7卷 125-130页

作者： Yongqiang shi LianSheng Li JianWu Chen FuChang Zuo XiaoPing Zhang ZhiWu Mei Li Wang Keke Zhang Beijing Institute of Control Engineering State Key Laboratory of Lunar and Planetary Sciences Macau University of Science and Technology

The solar X-ray detector(SXD) onboard the Macau Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle. The SXD includes two parts: a soft X-ray detection unit and a hard X-ray detection unit. Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators, two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector), and a processing circuit. Compared with similar instruments, the energy range of the SXD is wider(1–600 ke V) and the energy resolution is better(150 e V at 5.9 ke V, 12% at 59.5 ke V, and 3% at 662 keV).

关键词： Macau Science Satellite-1B (MSS-1B) solar X-ray detector solar X-ray spectrometer

Response of community composition and biomass of submerged macrophytes to variation in underwater light, wind and trophic status in a large eutrophic shallow lake

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Journal of Environmental Sciences 2021年第5期33卷 298-310页

作者： Baili Dong yongqiang Zhou Erik Jeppesen Kun shi Boqiang Qin Taihu Laboratory for Lake Ecosystem Research State Key Laboratory of Lake Science and EnvironmentNanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China Department of Bioscience Aarhus UniversityVejlsovej 258600 SilkeborgDenmark Sino-Danish Centre for Education and Research(SDC) University of Chinese Academy of SciencesBeijing 100049China Limnology Laboratory Department of Biological Sciences and Centre for Ecosystem Research and ImplementationMiddle East Technical UniversityAnkaraTurkey

Light climate is of key importance for the growth, community composition of submerged macrophytes in lakes and, they, in turn, are affected by lake depth and the degree of eutrophication. To test the relationships between submerged macrophyte presence and the ratio of Secchi disk depth(SDD) to water depth, i.e. SDD/depth, nutrients and wind, we conducted an extensive sampling campaign in a macrophyte-dominated area of the eastern region( n = 36) in 2016 in Lake Taihu, China, and combined the data gathered with results from extensive physico-chemical monitoring data from the entire lake. We confirmed that SDD/Depth is the primary factor controlling the community composition of macrophytes and showed that plant abundance increased with increasing SDD/Depth ratio( p 0.4 ensured growth of submerged macrophytes. Total phosphorus and total nitrogen also influenced the growth and community composition of macrophytes( p 0.05). The key to restore the macrophyte beds in the lake is to reduce the nutrient loading. A decrease of the water level may contribute as well in the shallow bays but will not bring plants back in the main part of the lake. As the tolerance of shade and nutrients varied among the species studied, this should be taken into account in the restoration of lakes by addition of plants.

关键词： Underwater light climate Water depth Community composition Macrophyte Eutrophication

Self-assembled donor-acceptor hole contacts for inverted perovskite solar cells with an efficiency approaching 22%: The impact of anchoring groups

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Journal of Energy Chemistry 2022年第5期31卷 87-95页

作者： Qiaogan Liao Yang Wang Zilong Zhang Kun Yang Yongqiang shi Kui Feng Bolin Li Jiachen Huang Peng Gao Xugang Guo Department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Functional Oxide Materials and DevicesSouthern University of Science and Technology(SUSTech)Shenzhen 518055GuangdongChina College of Materials Fujian Key Laboratory of Advanced MaterialsXiamen UniversityXiamen 361005FujianChina CAS Key Laboratory of Design and Assembly of Functional Nanostructures Fujian Provincial Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001HeilongjiangChina

Self-assembled molecules(SAMs) have shown great potential in replacing bulk charge selective contact layers in high-performance perovskite solar cells(PSCs) due to their low material consumption and simple processing. Herein, we design and synthesize a series of donor-acceptor(D-A) type SAMs(MPA-BTCA, MPA-BT-BA, and MPA-BT-RA, where MPA is 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline;BT is benzo[c][1,2,5]-thiadiazole;CA is 2-cyanoacrylic acid, BA is benzoic acid, RA is rhodanine-3-propionic acid) with distinct anchoring groups, which show dramatically different properties. MPA-BTCA with CA anchoring groups exhibited stronger dipole moments and formed a homogeneous monolayer on the indium tin oxide(ITO) surface by adopting an upstanding self-assembling mode. However, the MPA-BT-RA molecules tend to aggregate severely in solid state due to the sp~3 hybridization of the carbon atom on the RA group, which is not favorable for achieving a long-range ordered self-assembled layer.Consequently, benefiting from high dipole moment, as well as dense and uniform self-assembled film,the device based on MPA-BT-CA yielded a remarkable power conversion efficiency(PCE) of 21.81%.Encouragingly, an impressive PCE approaching 20% can still be obtained for the MPA-BT-CA-based PSCs as the device area is increased to 0.80 cm^(2). Our work sheds light on the design principles for developing hole selecting SAMs, which will pave a way for realizing highly efficient, flexible, and large-area PSCs.

关键词： Self-assembled molecules Donor-acceptor backbones Hole contacts Perovskite solar cells Anchoring groups