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Design of digital calibration based on variable step size of sub-binary SAR ADC

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The Journal of China Universities of Posts and Telecommunications 2024年第2期31卷 62-71页

作者： liu wei Zhao Yanke Shang Shiguang School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China

Addressing the impact of capacitor mismatch on the conversion accuracy of successive approximation register analog-to-digital converter(SAR ADC),a 12-bit 1 MS/s sub-binary SAR ADC designed using variable step size digital calibration was *** least mean square(LMS)calibration algorithm was employed with a ramp signal used as the calibration *** errors,extracted under injected disturbances,underwent iterative training to optimize weight *** address the trade-off between conversion accuracy and speed caused by a fixed step size,a novel variable step size algorithm tailored for SAR ADC calibration was *** core circuit and layout of the SAR ADC were implemented using the Taiwan Semiconductor Manufacturing Company(TSMC)0.35μm complementary metal-oxide-semiconductor(CMOS)commercial *** of the SAR ADC calibration algorithm was conducted using Simulink,demonstrating quick convergence and meeting conversion accuracy requirements compared to fixed step size *** results indicated that the convergence speed of the LMS digital calibration algorithm with variable step size was approximately eight times faster than that with a fixed step size,also yielding a lower mean square error(MSE).After calibration,the simulation results for the SAR ADC exhibited an effective number of bit(ENOB)of 11.79 bit and a signal-to-noise and distortion ratio(SNDR)of 72.72 dB,signifying a notable enhancement in the SAR ADC performance.

关键词： successive approximation register analog-to-digital converter(SAR ADC) variable step size digital calibration disturbance technique

NONMONOTONE LOCAL MINIMAX METHODS FOR FINDING MULTIPLE SADDLE POINTS

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Journal of Computational Mathematics 2024年第3期42卷 851-884页

作者： wei liu Ziqing Xie Wenfan Yi South China Research Center for Applied Mathematics and Interdisciplinary Studies South China Normal UniversityGuangzhou 510631China Key Laboratory of Computing and Stochastic Mathematics(Ministry of Education) Hunan Normal UniversityChangshaHunan 410081China Hunan Provincial Key Laboratory of Intelligent Information Processing and Applied Mathematics School of MathematicsHunan UniversityChangshaHunan 410082China

In this paper,by designing a normalized nonmonotone search strategy with the BarzilaiBorwein-type step-size,a novel local minimax method(LMM),which is a globally convergent iterative method,is proposed and analyzed to find multiple(unstable)saddle points of nonconvex functionals in Hilbert *** to traditional LMMs with monotone search strategies,this approach,which does not require strict decrease of the objective functional value at each iterative step,is observed to converge faster with less ***,based on a normalized iterative scheme coupled with a local peak selection that pulls the iterative point back onto the solution submanifold,by generalizing the Zhang-Hager(ZH)search strategy in the optimization theory to the LMM framework,a kind of normalized ZH-type nonmonotone step-size search strategy is introduced,and then a novel nonmonotone LMM is *** feasibility and global convergence results are rigorously carried out under the relaxation of the monotonicity for the functional at the iterative ***,in order to speed up the convergence of the nonmonotone LMM,a globally convergent Barzilai-Borwein-type LMM(GBBLMM)is presented by explicitly constructing the Barzilai-Borwein-type step-size as a trial step-size of the normalized ZH-type nonmonotone step-size search strategy in each ***,the GBBLMM algorithm is implemented to find multiple unstable solutions of two classes of semilinear elliptic boundary value problems with variational structures:one is the semilinear elliptic equations with the homogeneous Dirichlet boundary condition and another is the linear elliptic equations with semilinear Neumann boundary *** numerical results indicate that our approach is very effective and speeds up the LMMs significantly.

关键词： Multiple saddle points Local minimax method Barzilai-Borwein gradient method Normalized nonmonotone search strategy Global convergence

TIMP-1 Promotes Expression of MCP-1 and Macrophage Migration by Inducing Fli-1 in Experimental Liver Fibrosis

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Journal of Clinical and Translational Hepatology 2024年第7期12卷 634-645页

作者： Xiaoli Huang Xiaofan Wang Yanhong Wang Shuangjun Shen wei Chen Tianhui liu ping Wang Xu Fan Lin liu Jidong Jia Min Cong Liver Research Center Beijing Friendship HospitalCapital Medical UniversityBeijingChina Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis and National Clinical Research Center of Digestive Disease BeijingChina Dongying People’s Hospital DongyingShandongChina Experimental and Translational Research Center Beijing Friendship HospitalCapital Medical UniversityBeijingChina

Background and Aims:Tissue inhibitor of metalloproteinase-1(TIMP-1)plays a role in the excessive generation of extracellular matrix in liver *** study aimed to explore the pathways through which TIMP-1 controls monocyte chemoattractant protein-1(MCP-1)expression and promotes hepatic macrophage ***:Liver fibrosis was triggered through carbon tetrachloride,and an adenoassociated virus containing small interfering RNA targeting TIMP-1(siRNA-TIMP-1)was administered to both rats and *** assessed the extent of fibrosis and macrophage *** molecular mechanisms regulating macrophage recruitment by TIMP-1 were investigated through transwell migration assays,luciferase reporter assays,the use of pharmacological modulators,and an analysis of extracellular vesicles(EVs).Results:siRNA-TIMP-1 alleviated carbon tetrachloride-induced liver fibrosis,reducing macrophage migration and MCP-1 ***-culturing macrophages with hepatic stellate cells(HSCs)post-TIMP-1 downregulation inhibited macrophage *** siRNATIMP-1-treated HSCs,microRNA-145(miRNA-145)expression increased,while the expression of Friend leukemia virus integration-1(Fli-1)and MCP-1 was *** of Fli-1 led to decreased MCP-1 expression,whereas Fli-1 overexpression increased MCP-1 expression within *** with miRNA-145 mimics reduced the expression of both Fli-1 and MCP-1,while miRNA-145 inhibitors elevated the expression of both Fli-1 and MCP-1 in ***-145 bound directly to the 3'-UTR of Fli-1,and mi RNA-145-EN-riched EVs secreted by HSCs after TIMP-1 downregulation influenced macrophage ***:TIMP-1 induces Fli-1 expression through miRNA-145,subsequently increasing MCP-1 expression and macrophage ***-145-enriched EVs from HSCs can transmit biological information and magnify the function of TIMP-1.

关键词： TIMP-1 Fli-1 MCP-1 miRNA-145 Liver fibrosis Extracellular vesicles

Transition metal clusters with precise numbers of atoms anchored on graphdiyne as multifunctional electrocatalysts for OER/ORR/HER:a computational study

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Rare Metals 2024年第7期43卷 3107-3117页

作者： Xin-Yang liu Jing-wei liu Gang Li Jing-Xiang Zhao College of Chemistry and Chemical Engineering Harbin Normal UniversityHarbin 150025China

Subnanometer metal clusters play an increasingly important role in heterogeneous catalysis due to their high catalytic activity and *** this work,by means of the density functional theory(DFT) calculations,the catalytic activities of transition metal clusters with precise numbers of atoms supported on graphdiyne(TM_(1-4)@GDY,TM=V,Cr,Mn,Fe,Co,Ni,Cu,Ru,Rh,Pd,Ir,Pt) were investigated for oxygen evolution reactions(OER),oxygen reduction reactions(ORR) and hydrogen evolution reactions(HER).The computed results reveal that the Pd_(2),Pd_(4) and Pt_(1) anchored graphdiyne can serve as trifunctional catalysts for OER/ORR/HER with the overpotentials of 0.49/0.37/0.06,0.45/0.33/0.12 and 0.37/0.43/0.01 V,respectively,while Pd_(1) and Pt_(2)@graphdiyne can exhibit excellent catalytic performance for water splitting(OER/HER) with the overpotentials of 0.55/0.17 and 0.43/0.03 *** addition,Ni_(1) and Pd_(3) anchored GDY can perform as bifunctional catalysts for metal-air cells(OER/ORR) and fuels cells(ORR/HER) with the overpotentials of 0.34/0.32 and 0.42/0.04 V,***,by precisely controlling the numbers of atoms in clusters,the TM_(1-4) anchored graphdiyne can serve as promising multifunctional electrocatalysts for OER/ORR/HER,which may provide an instructive strategy to design catalysts for the energy conversation and storage devices.

关键词： Density functional theory Graphdiyne Single-cluster catalysts Multifunctional electrocatalysts Overpotential

Changes in Spring Snow Cover over the Eastern and Western Tibetan Plateau and Their Associated Mechanism

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Advances in Atmospheric Sciences 2024年第5期41卷 959-973页

作者： Fangchi liu Xiaojing JIA wei DONG Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhouZhejiang 310058China

The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–*** current work investigates the possible mechanisms accounting for these distinct TPSC *** results indicate that the decrease in W_TPSC is primarily attributed to rising temperatures,while the increase in E_TPSC is closely linked to enhanced *** circulation analysis shows that the essential system responsible for the TPSC changes is a significant anticyclonic system centered over the northwestern *** anomalous descending motion and adiabatic heating linked to this anticyclone leads to warmer temperatures and consequent snowmelt over the western ***,anomalous easterly winds along the southern flank of this anticyclone serve to transport additional moisture from the North Pacific,leading to an increase in snowfall over the eastern *** analysis reveals that the anomalous anticyclone is associated with an atmospheric wave pattern that originates from upstream *** warming of the subtropical North Atlantic(NA)sea surface temperature(SST)induces an atmospheric pattern resembling a wave train that travels eastward across the Eurasian continent before reaching the ***,the decline in winter sea ice(SIC)over the Barents Sea exerts a persistent warming influence on the atmosphere,inducing an anomalous atmospheric circulation that propagates southeastward and strengthens the northwest TP anticyclone in ***,an enhancement of subtropical stationary waves has resulted in significant increases in easterly moisture fluxes over the coastal areas of East Asia,which further promotes more snowfall over eastern TP.

关键词： snow cover Tibetan Plateau long-term changes spring

Synergistic anionic/zwitterionic mixed surfactant system with high emulsification efficiency for enhanced oil recovery in low permeability reservoirs

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Petroleum Science 2024年第2期21卷 936-950页

作者： Hai-Rong Wu Rong Tan Shi-ping Hong Qiong Zhou Bang-Yu liu Jia-wei Chang Tian-Fang Luan Ning Kang Ji-Rui Hou National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing102249China Unconventional Petroleum Research Institute China University of Petroleum-BeijingBeijing102249China Gas Production Plant 5 of PetroChina Changqing Oilfield Company PetroChinaXi'an710000ShaanxiChina College of Petroleum Engineering China University of Petroleum-BeijingBeijing102249China College of Science China University of Petroleum-BeijingBeijing102249China Kazakh-British Technical University Almaty050000Kazakhstan

Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.

关键词： Anionic/zwitterionic mixed surfactant system Emulsification Synergistic effect Low permeability reservoir Enhanced oil recovery

Study on moisture absorption characteristics of glass fibrereinforced epoxy resin material for composite insulators based on the 3D-Fick model

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High Voltage 2024年第4期9卷 888-901页

作者： Yuming Zhang Yunpeng liu Sizu Hou Jianghai Geng ping Wang Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina Hebei Key Laboratory of Power Internet of Things Technology BaodingChina

Long-term exposure to moisture leads to a gradual deterioration of performance and reduced service life of glass fibre-reinforced epoxy resin(GFRP)material in composite ***,it is necessary to analyse the moisture absorption characteristics of GFRP material and the evolution of damage to their internal interface *** absorption tests on GFRP rod material used in composite insulators to obtain their three-dimensional diffusion coefficients are *** force microscopy was then employed to obtain the composite material system's fibre/matrix interfacial phase ***,a finite element model incorporating representative volume elements with interfacial phases and a mesoscale transient moisture absorption finite element model for the composite material was ***,the moisture absorption characteristics of GFRP material and the evolution of damage to the interfacial phase under thermal-humidity cycling conditions were *** results showed that the diffusion coefficient along the fibre direction in GFRP material was higher than that in the perpendicular *** moisture diffusion finite element model,incorporating an anisotropic interfacial phase,fitted the anisotropic diffusion coefficients of GFRP material more *** moisture invaded the GFRP material,the mismatch stresses continuously increased during the moisture ***,the non-uniform arrangement of fibres resulted in uneven distribution of moistureinduced stresses inside the material,leading to higher mismatch stresses in areas with dense fibre arrangements in the *** high and low humidity cycles led to the development of micro-cracks,micro-porosity,and interface debonding along the fibre direction at the GFRP material interfaces,thereby affecting the anisotropic moisture absorption characteristics of the *** findings of this study provide valuable insights into the mechanisms underlying the

关键词： composite fibre moisture

Pickering emulsion transport in skeletal muscle tissue:A dissipative particle dynamics simulation approach

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Chinese Journal of Chemical Engineering 2024年第4期68卷 65-75页

作者： Xuwei liu wei Chen Yufei Xia Guanghui Ma Reiji Noda wei Ge State Key Laboratory of Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Division of Environmental Engineering Science Graduate School of Science and TechnologyGunma University1-5-1 Tenjin-choKiryuGunma 376-8515Japan State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing 100190China

Lymph node targeting is a commonly used strategy for particulate vaccines,particularly for Pickering ***,extensive research on the internal delivery mechanisms of these emulsions,especially the complex intercellular interactions of deformable Pickering emulsions,has been surprisingly *** gap in knowledge holds significant potential for enhancing vaccine *** study aims to address this by summarizing the process of lymph-node-targeting transport and introducing a dissipative particle dynamics simulation method to evaluate the dynamic processes within cell *** transport of Pickering emulsions in skeletal muscle tissue is specifically investigated as a case *** factors impacting the transport process are explored,including local cellular tissue environmental factors and the properties of the Pickering emulsion *** simulation results primarily demonstrate that an increase in radial repulsive interaction between emulsion particles can decrease the transport ***,larger intercellular gaps also diminish the transport efficiency of emulsion droplet particles due to the increased motion complexity within the intricate transport space compared to a single *** study sheds light on the nuanced interplay between engineered and biological systems influencing the transport dynamics of Pickering *** insights hold valuable potential for optimizing transport processes in practical biomedical applications such as drug ***,the desired transport efficiency varies depending on the specific *** instance,while a more rapid transport might be crucial for lymph-node-targeted drug delivery,certain applications requiring a slower release of active components could benefit from the reduced transport efficiency observed with increased particle repulsion or larger intercellular gaps.

关键词： Pickering emulsion Skeletal muscular cells Transport phenomena Dissipative particle dynamics Drug delivery

Constructing highly safe and long-life calcium ion batteries based on hydratedvanadium oxide cathodes featuring a pillar structure

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Rare Metals 2024年第6期43卷 2597-2612页

作者： Chun-Fang Wang Shi-wei Zhang Lan Huang Yuan-Min Zhu Feng liu Jian-Chuan Wang Li-Ming Tan Chun-Yi Zhi Cui-ping Han Powder Metallurgy Research Institute Central South UniversityChangsha410083China Songshan Lake Materials Laboratory Dongguan 523808China Research Institute of Interdisciplinary Science and School of Materials Science and Engineering Dongguan University of TechnologyDongguan 523808China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China Faculty of Materials Science and Energy Engineering/Institute of Technology for Carbon Neutrality Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Calcium-ion batteries(CIBs)have generated intense interest due to the growing demand for safer,cheaper,and large-scale energy storage ***,their development is still in its infancy,owing to the lack of suitable cathodes for sustaining reversiblc Ca^(2+)intercalation/***,layered H_(2)V_(3)O_(8)(HVO)with Zn^(2+)pre-insertion(ZHVO)is reported as a high-rate and highly durable cathode material for *** existence of Zn^(2+)and H_(2)O pillars could expand the interlayer spacing up to 1.8 nm,which is favorable for the diffusion of bulky Ca^(2+).The formation of Zn-O bonds facilitates electron transfer and enhances electrical ***,the ZHVO cathode achieves superior capacity performance(213.9 mAh·g^(-1)at 0.2 A·g^(-1))and long lifespan(78.3%for 1,000 cycles at 5 A·g^(-1))compared to pristine *** functional theory(DFT)calculations revealed that Zn^(2+)moved during Ca^(2+)intercalation,thereby reducing the diffusion energy barrier and facilitating Ca^(2+)***,a safe aqueous calcium ion cell was successfully assembled.

关键词： Multivalent batteries Calcium-ion batteries Layered structure Vanadium oxide Cathode materials