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大型线性方程组(集)的分段分片直接解法及其与子结构法的偶合

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高等学校计算数学学报 1980年第1期 1-6页

作者：叶碧泉冯振兴李茂祥沈成武武汉大学

本文提出了一种求解大型线代数方程(正定)组集的直接解法,称为分段、分片解法(D.S.P)。它是基于LDL~T分解的一种改进算法,可用于含多组右端向量的方程集,并适用于大带宽矩阵,可兼顾节省计算机容量与时间。与文[1]、[2]相比,本解法用分... 详细信息

本文提出了一种求解大型线代数方程(正定)组集的直接解法,称为分段、分片解法(D.S.P)。它是基于LDL~T分解的一种改进算法,可用于含多组右端向量的方程集,并适用于大带宽矩阵,可兼顾节省计算机容量与时间。与文[1]、[2]相比,本解法用分片处理克服了带宽过大时引起的所谓“超段”问题;并提出与子结构法偶合,以有效地处理多叉式结构。

关键词：线性方程组内点直接法有限元法子结构法解法幺矩阵单位矩阵子块偶合矩阵求逆

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食品4D打印技术在食品工业中的应用进展

食品工业科技 2025年第1期46卷 424-430页

作者：童强肖帅磊毕野吴豪董秀萍大连工业大学机械工程与自动化学院辽宁大连116034 海洋食品加工与安全控制全国重点实验室国家海洋食品工程技术研究中心辽宁省海产品精深加工产业共性技术创新平台大连市中式预制食品技术创新中心辽宁大连116034 大连工业大学食品交叉科学研究院辽宁大连116034

4D打印技术作为在3D打印的基础上增加了“时间”这个维度的新兴打印技术,不仅可以在三维空间内构建复杂结构,还能通过材料的预设形变来实现打印物体的自我组装和形态变化。4D打印技术作为新一代的增材制造技术,因演变过程完全可预测、... 详细信息

4D打印技术作为在3D打印的基础上增加了“时间”这个维度的新兴打印技术,不仅可以在三维空间内构建复杂结构,还能通过材料的预设形变来实现打印物体的自我组装和形态变化。4D打印技术作为新一代的增材制造技术,因演变过程完全可预测、可设计和可控制的特点,其潜力和影响力正在不断扩大。近年来,4D打印技术在现代食品加工领域也得到了广泛的研究和应用,通过4D打印实现食品结构、营养成分、口感等特性的精准控制。本文综述了食品4D打印技术原理、要素及优势,分析了食品4D打印在现代食品加工领域中的应用进展,包括4D打印材料特性、外界刺激等方面,并重点探讨了4D打印智能食品的微观结构控制与口感之间的关系,最后展望了食品4D打印技术发展趋势和挑战,旨在为现代食品加工领域提供参考借鉴。

关键词： 4D打印增材制造食品加工外界刺激微结构控制

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High-precision magnetic field measurement system based on a coherent population trapping magnetometer onboard the SATech-01 satellite

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Science China Technological Sciences 2025年

作者： Hongbo XUE Wei SONG Haoran ZHAO Yiteng ZHANG Shanzhi ye Jindong WANG Ran TAO Peng SANG Keli CHEN Xingzi bi bingjun CHENG bin ZHOU Yongliang XUE Yingying TANG Liu LIU Jinsong LI Xiaocheng ZHU Baoquan LI Jinguo LIU Wen CHEN Xiaofeng ZHANG Yonghe ZHANG Lei LI State Key Laboratory of Space Weather National Space Science Center Chinese Academy of Sciences Key Laboratory of Solar Activity and Space Weather National Space Science Center Chinese Academy of Sciences Key Laboratory of Electronics and Information Technology for Space Systems National Space Science Center Chinese Academy of Sciences State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Innovation Academy for Microsatellites Chinese Academy of Sciences

On July 27, 2022, a high-precision system for measuring the magnetic field based on a coherent population trapping magnetometer（referred to as the CPT system） was launched onboard the Space Advanced Technology demonstration satellite（SATech-01） by a ZK-1A rocket. The payload comprises a scalar coherent population trapping magnetometer（CPTM）, triaxial anisotropic magnetoresistance magnetometer（AMRM）, and nano star tracker mounted on a non-magnetic telescopic tubular mast. This configuration enables synchronized measurement of scalar and vector geomagnetic fields, as well as the attitude,making the payload with its compact sensors suitable for applications on miniature satellite platforms. On November 7, 2022,the novel telescopic tubular mast was deployed in orbit, extending to a length of 5.28 m. The CPTM, an absolute scalar magnetometer with an omnidirectional sensor, is the first China-developed quantum/atomic magnetometer successfully operating in space. In orbit, the CPTM has sensitivity of ～10 pT/Hz1/2and can automatically operate under complex magnetic field variations. The difference between the scalar fields obtained using the CPTM and CHAOS model has a mean deviation of–3.73 n T and a standard deviation of 26.11 nT（1σ）, without on-orbit calibration or correction. The miniaturized AMRM has a sensitivity of ～0.3 n T/Hz1/2and maintains stable and reliable operation in orbit. The low-power and miniaturized nano star tracker has a measurement uncertainty of 14.23″（1σ） in orbit. The mission has realized the on-orbit technical verification of the integrated and synchronized detection of the vector magnetic field and attitude and fully validated the system's performance,automation level, and reliability.

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Advances in theoretical study on transition-metal-catalyzed C-H activation

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Science China Chemistry 2016年第11期59卷 1448-1466页

作者： Yuan-ye Jiang Xiaoping Man Siwei bi School of Chemistry and Chemical Engineering Qufu Normal University

Transition-metal-catalyzed C–H activation represents one of most attractive research fields in modern organic chemistry while theoretical studies have become a popular and effective tool for elucidating mechanism nowadays. The recent achievements in the cross field of the two orientations are reviewed in this article. The first part introduced the advances in theoretical study on transition-metal-catalyzed C–H activation. The elegant work reported mainly in and after 2013, classified according to the mechanisms of C–H activation, were covered. The second part provided an analysis on the distribution of quantum-chemical methods, solvation models and basis sets in the collected theoretical studies.

关键词： transition metal C–H activation mechanism DFT

Interface temperature evolution exposed to arc discharges occurred on the uniform moist pollution layer of composite insulators based on interface fibre Bragg gratings

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High Voltage 2022年第4期7卷 763-770页

作者： Yanpeng Hao Jikai bi quan Wang Lin Yang School of Electric Power South China University of TechnologyGuangzhouChina

Arc discharges of moist polluted composite insulators pose a serious threat to the stable operation of transmission ***,there is no effective detection technology for arc *** evolution mechanism of interface temperature accompanied by arc discharges is not *** this paper,a 10 kV composite insulator with quasi-distributed fibre Bragg gratings(FBGs)embedded at the insulator core-housing interface was *** temperature calibration experiment of interface FBGs,and the arc dis-charges experiment of the uniform moist polluted composite insulator were *** voltage was controlled to get the continuous arc with an arc time of 46 s and the intermittent arc with an arc time of 8 *** to the two types of surface arcs,the interface temperature evolution was explored.A new phenomenon of the sharp drop of the interface temperature was observed:the interface temperature first drops sharply and then rises rapidly during the continuous *** results show that quasi-distributed FBGs are valid for detecting the two types of surface arcs by interface temperature *** paper provides a technical means to evaluate the state of surface discharges and insulating properties of composite insulators.

关键词： interface composite insulator

A simplified physically-based algorithm for surface soil moisture retrieval using AMSR-E data

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Frontiers of Earth Science 2014年第3期8卷 427-438页

作者： Jiangyuan ZENG Zhen LI quan CHEN Haiyun bi Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Beijing 100094 China University of Chinese Academy of Sciences Beijing 100049 China

A simplified physically-based algorithm for surface soil moisture inversion from satellite microwave radiometer data is presented. The algorithm is based on a radiative transfer model, and the assumption that the optical depth of the vegetation is polarization independent. The algorithm combines the effects of vegetation and roughness into a single parameter. Then the microwave polarization difference index （MPDI） is used to eliminate the effects of surface temperature, and to obtain soil moisture, through a nonlinear iterative procedure. To verify the present algorithm, the 6.9 GHz dual-polarized brightness temperature data from the Advanced Micro- wave Scanning Radiometer （AMSR-E） were used. Then the soil moisture values retrieved by the present algorithm were validated by in-situ data from 20 sites in the Tibetan Plateau, and compared with both the NASA AMSR-E soil moisture products, and Soil Moisture and Ocean Salinity （SMOS） soil moisture products. The results show that the soil moisture retrieved by the present algorithm agrees better with ground measurements than the two satellite products. The advantage of the algorithm is that it doesn＇t require field observations of soil moisture, surface roughness, or canopy biophysical data as calibration parameters, and needs only single-frequency brightness temperature observations during the whole retrieval process.

关键词： passive microwave remote sensing soilmoisture inversion AMSR-E SMOS

quantum nature of proton transferring across one-dimensional potential fields

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Chinese Physics B 2021年第4期30卷 417-424页

作者： Cheng bi quan Chen Wei Li Yong Yang Key Laboratory of Photovoltaic and Energy Conservation Materials Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230026China Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China

Proton transfer plays a key role in the applications of advanced energy materials as well as in the functionalities of biological *** this work,based on the transfer matrix method,we study the quantum effects of proton transfer in a series of one-dimensional(1 D) model potentials and numerically calculate the quantum probability of transferring across single and double barriers(wells).In the case of single barriers,when the incident energies of protons are above the barrier height,the quantum oscillations in the transmission coefficients depend on the geometric shape of the *** is found that atomic resonant tunneling(ART) not only presents in the rectangular single well and rectangular double barriers as expected,but also exists in the other types of potential wells and double *** hetero-structured double barriers,there is no resonant tunneling in the classical forbidden zone,i.e.,in the case when the incident energy(E_(i)) is lower than the barrier height(E_(b)).Furthermore,we have provided generalized analysis on the characteristics of transmission coefficients of hetero-structured rectangular double barriers.

关键词： proton transfer nuclear quantum effects atomic resonant tunneling double barriers

Characteristic analysis of lock-in for an elastically suspended airfoil in transonic buffet flow

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Chinese Journal of Aeronautics 2016年第1期29卷 129-143页

作者： quan Jingge Zhang Weiwei Gao Chuanqiang ye Zhengyin School of Aeronautics Northwestern Ploytechnical University

Numerical simulations are performed to study the aeroelastic responses of an elastically suspended airfoil in transonic buffet flow, by coupling the unsteady Reynolds-averaged Navier- Stokes （RANS） equations and structural motion equation. The current work focuses on the char- acteristic analysis of the lock-in phenomenon. Great attentions are paid to studying the frequency range of lock-in and the effects of the three parameters, namely the structural natural frequency, mass ratio and structural damping, on lock-in characteristic of the elastic system in detail. It is found that when the structural natural frequency is close to the buffet frequency, the coupling fre- quency of the elastic system is no longer equal to the buffet frequency, but keeps the same value as the structural natural frequency. The frequency lock-in occurs and stays present until the structural nature frequency is near the double buffet frequency. It means that the lock-in presents within a broad range, of which the lower threshold is near the buffet frequency, while the upper threshold is near the double buffet frequency. Moreover, the frequency range of lock-in is affected by mass ratio and structural damping. The lower the mass ratio and structural damping are, the wider the range of lock-in will be. The upper threshold of lock-in grows with the mass ratio and structural damping decreasing, but the lower threshold always keeps the same.

关键词： Aeroelastic analysisBuffet Elastic airfoil Lock-in Transonic flow

6-DOF MOTION AND CENTER OF ROTATION ESTIMATION BASED ON STEREO VISION

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Chinese Journal of Mechanical Engineering 2008年第2期21卷 87-92页

作者： CAO Wanpeng bi Wei CHE Rensheng GUO Wenbo ye Dong Department of Automatic Measurement and Control Harbin Institute of Technology Harbin 150001 China China Academy of Machinery Science and Technology Beijing 100044 China Department of Electrical Engineering and Automation Harbin Institute of Technology Harbin 150001 China

A new motion model and estimation algorithm is proposed to compute the general rigid motion object＇s 6-DOF motion parameters and center of rotation based on stereo vision. The object＇s 6-DOF motion model is designed from the rigid object＇s motion character under the two defined reference frames. According to the rigid object＇s motion model and motion dynamics knowledge, the corresponding motion algorithm to compute the 6-DOF motion parameters is worked out. By the rigid object pure rotation motion model and space sphere geometry knowledge, the center of rotation may be calculated after eliminating the translation motion out of the 6-DOF motion. The motion equations are educed based on the motion model and the closed-form solutions are figured out. To heighten the motion estimation algorithm＇s robust, RANSAC algorithm is applied to delete the outliers. Simulation and real experiments are conducted and the experiment results are analyzed. The results prove the motion model＇s correction and algorithm＇s validity.

关键词： Motion estimation Center of rotation 6-DOF motion Stereo vision