The paper deals with state estimation problem of nonlinear non-Gaussian discrete dynamic systems for improvement of accuracy and consistency. An efficient new algorithm called the adaptive Gaussian-sum square-root cub...The paper deals with state estimation problem of nonlinear non-Gaussian discrete dynamic systems for improvement of accuracy and consistency. An efficient new algorithm called the adaptive Gaussian-sum square-root cubature Kalman filter（AGSSCKF） with a split-merge scheme is proposed. It is developed based on the squared-root extension of newly introduced cubature Kalman filter（SCKF） and is built within a Gaussian-sum framework. Based on the condition that the probability density functions of process noises and initial state are denoted by a Gaussian sum using optimization method, a bank of SCKF are used as the sub-filters to estimate state of system with the corresponding weights respectively, which is adaptively updated. The new algorithm consists of an adaptive splitting and merging procedure according to a proposed split-decision model based on the nonlinearity degree of measurement. The results of two simulation scenarios（one-dimensional state estimation and bearings-only tracking） show that the proposed filter demonstrates comparable performance to the particle filter with significantly reduced computational cost.展开更多
Merged satellite altimeter products are widely used in ocean-related fields.Currently,the altimeter merged products of archiving validation and interpretation of satellite oceanographic(AVISO)data are widely used inte...Merged satellite altimeter products are widely used in ocean-related fields.Currently,the altimeter merged products of archiving validation and interpretation of satellite oceanographic(AVISO)data are widely used internationally.Chinese National Satellite Ocean Application Service also released merged altimeter products(ALT MUL)in 2023.However,there are few studies on the quality assessment of ALT MUL.Based on the data of AVISO merged products,Jason3 satellite,tide gauge and drifter buoy,the quality assessment and effect analysis of ALT MUL merged products were carried out by means of error evaluation index,interpolation along rails,velocity inversion and power spectrum.The result shows that the average sea level anomaly(SLA)of ALT MUL is about 2 cm smaller than that of AVISO.And they are consistent with the large-scale characteristics and spatial distribution.These two SLA products are both in accordance with normal distribution.Results indicate a lesser congruence between ALT MUL and Jason3 satellite compared to AVISO.This difference may be attributed to the fact that AVISO products use Jason3 satellite as crosscalibrated reference satellite during the merged process.Comparing the matching effect of the two merged products with the tide gauge and drifter buoy,ALT MUL merged products are superior to AVISO in general.The energy spectral density was calculated by using Jason3 satellite data along the orbit,and the two merged products were interpolated to the data points along the orbit.The effective resolution of AVISO and ALT MUL merged products was 180 km and 210 km respectively through spectral calculation,indicating that AVISO merged products have higher effective resolution.展开更多
Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen e...Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen evolution reaction(HER)and the anodic oxygen evolution reaction(OER).Transition metal-based catalysts have garnered significant research interest as promising alternatives to noble-metal catalysts,owing to their low cost,tunable composition,and noble-metal-like catalytic activity.Nevertheless,systematic reviews on their application as bifunctional catalysts for overall water splitting(OWS)are still limited.This review comprehensively outlines the principal categories of bifunctional transition metal electrocatalysts derived from electrospun nanofibers(NFs),including metals,oxides,phosphides,sulfides,and carbides.Key strategies for enhancing their catalytic performance are systematically summarized,such as heterointerface engineering,heteroatom doping,metal-nonmetal-metal bridging architectures,and single-atom site design.Finally,current challenges and future research directions are discussed,aiming to provide insightful perspectives for the rational design of high-performance electrocatalysts for OWS.展开更多
Herein,we have developed a straightforward wet-chemical method to synthesize a series of Pd-based alloy nanowires(NWs),including Pd Pt NWs,Pd Au NWs,Pd Ir NWs,and Pd Ru NWs,which exhibits high mass activity and turnov...Herein,we have developed a straightforward wet-chemical method to synthesize a series of Pd-based alloy nanowires(NWs),including Pd Pt NWs,Pd Au NWs,Pd Ir NWs,and Pd Ru NWs,which exhibits high mass activity and turnover frequency(TOF) for HER,surpassing Pt/C by 4.6-fold and 1.5-fold in acidic and alkaline electrolytes,respectively.It also demonstrates high stability in alkaline electrolyte at a current density of 220 m A/cm^(2) for 280 h,highlighting its potential for practical applications under industrial current conditions.Pd Pt NWs exhibited ultrathin structures with head-to-tail kinks and inherent defects,significantly increasing the density of active sites and precisely tuning the electronic structure,which could accelerate reaction kinetics and boost water-splitting electrocatalytic performance.This study highlights the potential of Pd Pt NWs as highly efficient catalysts,offering outstanding catalytic performance and stability for practical applications.展开更多
The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix sp...The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix splitting methods.Taking the decomposition of the diagonal elements for coefficient matrix as the key point,some new preconditioners are constructed.Taking the tri-diagonal coefficient matrix as an example,the convergence domains and optimal relaxation factor of the new method are analyzed theoretically.The presented new iteration methods are applied to solve linear algebraic equations,even 2D and 3D diffusion problems with the fully implicit discretization.The results of numerical experiments are matched with the theoretical analysis,and show that the iteration numbers are reduced greatly.The superiorities of presented iteration methods exceed some classical iteration methods dramatically.展开更多
目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,...目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。展开更多
Pharmacophore is a commonly used method for molecular simulation, including ligand-based pharmacophore （LBP） and structure-based pharmacophore （SBP）. LBP can be utilized to identify active compounds usual with low...Pharmacophore is a commonly used method for molecular simulation, including ligand-based pharmacophore （LBP） and structure-based pharmacophore （SBP）. LBP can be utilized to identify active compounds usual with lower accuracy, and SBP is able to use for distin- guishing active compounds from inactive compounds with frequently higher missing rates. Merged pharmacophore （MP） is presented to integrate advantages and avoid shortcomings of LBP and SBP. In this work, LBP and SBP models were constructed for the study of per- oxisome proliferator receptor-alpha （PPARα） agonists. According to the comparison of the two types of pharmacophore models, mainly and secondarily pharmacological features were identified. The weight and tolerance values of these pharmacological features were adjusted to construct MP models by single-factor explorations and orthogonal experimental design based on SBP model. Then, the reliability and screening efficiency of the best MP model were validated by three databases. The best MP model was utilized to compute PPARα activity of compounds from traditional Chinese medicine. The screening efficiency of MP model outperformed individual LBP or SBP model for PPARα agonists, and was similar to combinatorial screening of LBP and SBP. However, MP model might have an advantage over the combination of LBP and SBP in evaluating the activity of compounds and avoiding the inconsistent prediction of LBP and SBP, which would be beneficial to guide drug design and optimization.展开更多
在循证医学时代下,依托规范的技术方法和标准化的操作规程发掘中医药独特优势,是实现中医药现代化、国际化发展并惠泽人类的必由之路。中医理论、人用经验和研究证据三结合证据体系的提出标志着中医药特色评价体系思维方法取得了重要进...在循证医学时代下,依托规范的技术方法和标准化的操作规程发掘中医药独特优势,是实现中医药现代化、国际化发展并惠泽人类的必由之路。中医理论、人用经验和研究证据三结合证据体系的提出标志着中医药特色评价体系思维方法取得了重要进步,经过恰当方法整合后的多元证据体是中医药临床指南推荐意见和循证卫生决策的有力支撑。本文基于当前国际证据合成与分级方法学前沿进展,初步提出中医药多元证据整合的方法学框架——MERGE(Merge Evidence-based Research and artificial intelliGence to support smart dEcision)框架,以期为中医药循证医学方法学体系的完善和发展提供借鉴和参考。展开更多
基金supported by the National Natural Science Foundation of China(No. 61032001)Shandong Provincial Natural Science Foundation of China (No. ZR2012FQ004)
文摘The paper deals with state estimation problem of nonlinear non-Gaussian discrete dynamic systems for improvement of accuracy and consistency. An efficient new algorithm called the adaptive Gaussian-sum square-root cubature Kalman filter（AGSSCKF） with a split-merge scheme is proposed. It is developed based on the squared-root extension of newly introduced cubature Kalman filter（SCKF） and is built within a Gaussian-sum framework. Based on the condition that the probability density functions of process noises and initial state are denoted by a Gaussian sum using optimization method, a bank of SCKF are used as the sub-filters to estimate state of system with the corresponding weights respectively, which is adaptively updated. The new algorithm consists of an adaptive splitting and merging procedure according to a proposed split-decision model based on the nonlinearity degree of measurement. The results of two simulation scenarios（one-dimensional state estimation and bearings-only tracking） show that the proposed filter demonstrates comparable performance to the particle filter with significantly reduced computational cost.
基金The National Key R&D Program of China under contract No.2021YFC3101503the National Natural Science Foundation of China under contract Nos 42276205 and 42406195+1 种基金the Hunan Provincial Natural Science Foundation of China under contract No.2023JJ10053the Youth Independent Innovation Science Foundation under contract No.ZK24-54.
文摘Merged satellite altimeter products are widely used in ocean-related fields.Currently,the altimeter merged products of archiving validation and interpretation of satellite oceanographic(AVISO)data are widely used internationally.Chinese National Satellite Ocean Application Service also released merged altimeter products(ALT MUL)in 2023.However,there are few studies on the quality assessment of ALT MUL.Based on the data of AVISO merged products,Jason3 satellite,tide gauge and drifter buoy,the quality assessment and effect analysis of ALT MUL merged products were carried out by means of error evaluation index,interpolation along rails,velocity inversion and power spectrum.The result shows that the average sea level anomaly(SLA)of ALT MUL is about 2 cm smaller than that of AVISO.And they are consistent with the large-scale characteristics and spatial distribution.These two SLA products are both in accordance with normal distribution.Results indicate a lesser congruence between ALT MUL and Jason3 satellite compared to AVISO.This difference may be attributed to the fact that AVISO products use Jason3 satellite as crosscalibrated reference satellite during the merged process.Comparing the matching effect of the two merged products with the tide gauge and drifter buoy,ALT MUL merged products are superior to AVISO in general.The energy spectral density was calculated by using Jason3 satellite data along the orbit,and the two merged products were interpolated to the data points along the orbit.The effective resolution of AVISO and ALT MUL merged products was 180 km and 210 km respectively through spectral calculation,indicating that AVISO merged products have higher effective resolution.
基金Supported by the National Natural Science Foundation of China(No.52273056)the Science and Technology Development Program of Jilin Province,China(No.YDZJ202501ZYTS305)。
文摘Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen evolution reaction(HER)and the anodic oxygen evolution reaction(OER).Transition metal-based catalysts have garnered significant research interest as promising alternatives to noble-metal catalysts,owing to their low cost,tunable composition,and noble-metal-like catalytic activity.Nevertheless,systematic reviews on their application as bifunctional catalysts for overall water splitting(OWS)are still limited.This review comprehensively outlines the principal categories of bifunctional transition metal electrocatalysts derived from electrospun nanofibers(NFs),including metals,oxides,phosphides,sulfides,and carbides.Key strategies for enhancing their catalytic performance are systematically summarized,such as heterointerface engineering,heteroatom doping,metal-nonmetal-metal bridging architectures,and single-atom site design.Finally,current challenges and future research directions are discussed,aiming to provide insightful perspectives for the rational design of high-performance electrocatalysts for OWS.
基金the financial support from the National Natural Science Foundation of China (Nos.21805170,22172093)Natural Science Foundation of Shandong Province (Nos.ZR2023QB219,ZR2021QB161)Qingdao Postdoctoral Innovation Project (No.QDBSH20220202031)。
文摘Herein,we have developed a straightforward wet-chemical method to synthesize a series of Pd-based alloy nanowires(NWs),including Pd Pt NWs,Pd Au NWs,Pd Ir NWs,and Pd Ru NWs,which exhibits high mass activity and turnover frequency(TOF) for HER,surpassing Pt/C by 4.6-fold and 1.5-fold in acidic and alkaline electrolytes,respectively.It also demonstrates high stability in alkaline electrolyte at a current density of 220 m A/cm^(2) for 280 h,highlighting its potential for practical applications under industrial current conditions.Pd Pt NWs exhibited ultrathin structures with head-to-tail kinks and inherent defects,significantly increasing the density of active sites and precisely tuning the electronic structure,which could accelerate reaction kinetics and boost water-splitting electrocatalytic performance.This study highlights the potential of Pd Pt NWs as highly efficient catalysts,offering outstanding catalytic performance and stability for practical applications.
基金The National Natural Science Foundations of China (12202219)the Natural Science Foundations of Ningxia (2024AAC02009, 2023AAC05001)the Ningxia Youth Top Talents Training Project。
文摘The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix splitting methods.Taking the decomposition of the diagonal elements for coefficient matrix as the key point,some new preconditioners are constructed.Taking the tri-diagonal coefficient matrix as an example,the convergence domains and optimal relaxation factor of the new method are analyzed theoretically.The presented new iteration methods are applied to solve linear algebraic equations,even 2D and 3D diffusion problems with the fully implicit discretization.The results of numerical experiments are matched with the theoretical analysis,and show that the iteration numbers are reduced greatly.The superiorities of presented iteration methods exceed some classical iteration methods dramatically.
文摘目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。
文摘Pharmacophore is a commonly used method for molecular simulation, including ligand-based pharmacophore （LBP） and structure-based pharmacophore （SBP）. LBP can be utilized to identify active compounds usual with lower accuracy, and SBP is able to use for distin- guishing active compounds from inactive compounds with frequently higher missing rates. Merged pharmacophore （MP） is presented to integrate advantages and avoid shortcomings of LBP and SBP. In this work, LBP and SBP models were constructed for the study of per- oxisome proliferator receptor-alpha （PPARα） agonists. According to the comparison of the two types of pharmacophore models, mainly and secondarily pharmacological features were identified. The weight and tolerance values of these pharmacological features were adjusted to construct MP models by single-factor explorations and orthogonal experimental design based on SBP model. Then, the reliability and screening efficiency of the best MP model were validated by three databases. The best MP model was utilized to compute PPARα activity of compounds from traditional Chinese medicine. The screening efficiency of MP model outperformed individual LBP or SBP model for PPARα agonists, and was similar to combinatorial screening of LBP and SBP. However, MP model might have an advantage over the combination of LBP and SBP in evaluating the activity of compounds and avoiding the inconsistent prediction of LBP and SBP, which would be beneficial to guide drug design and optimization.
文摘在循证医学时代下,依托规范的技术方法和标准化的操作规程发掘中医药独特优势,是实现中医药现代化、国际化发展并惠泽人类的必由之路。中医理论、人用经验和研究证据三结合证据体系的提出标志着中医药特色评价体系思维方法取得了重要进步,经过恰当方法整合后的多元证据体是中医药临床指南推荐意见和循证卫生决策的有力支撑。本文基于当前国际证据合成与分级方法学前沿进展,初步提出中医药多元证据整合的方法学框架——MERGE(Merge Evidence-based Research and artificial intelliGence to support smart dEcision)框架,以期为中医药循证医学方法学体系的完善和发展提供借鉴和参考。
