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Feasible synthesis of porous h-BN by Mg^(2+)induced lattice dislocations for hydrogen and ammonia storage

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Nano Research 2025年第1期18卷 94-99页

作者： Xiaojia Huang Zihao wang Yihan Kong Li Jiang Baolin wang Jiangtao Jia Heping ma Guangshan zhu Key Laboratory of Polyoxometalate and Reticular material Chemistry of Ministry of Education Northeast Normal UniversityChangchun 130024China School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an 710049China

Hexagonal boron nitride(h-BN)is a two-dimensional(2D)layered material with a structure similar to graphite and it has potential as a hydrogen and ammonia storage ***,dense packing in the standard h-BN structure limits its surface area and prevents the B and N from being adsorption *** this study,the addition of Mg^(2+)during h-BN synthesis facilitated the growth of lattice dislocations and led to a crosslinked three-dimensional(3D)porous structure.A proposed formation mechanism for porous h-BN was confirmed by several characterization routes,most clearly by high-resolution transmission electron microscopy(HRTEM).Porous Mg/BNs exhibited high H_(2)and NH_(3)uptakes and showed potential for H_(2)and NH_(3)storage.

关键词： hexagonal boron nitride porous material dislocation gas storage

Label fusion for segmentation via patch based on local weighted voting

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Frontiers of Information Technology & Electronic Engineering 2017年第5期18卷 680-688页

作者： Kai zhu Gang LIU Long ZHAO wan ZHANG School of Automation Engineering Shanghai University of Electrical Power Athinoula A.martinos Center for Biomedical Imaging Massachusetts General HospitalHarvard Medical School

Label fusion is a powerful image segmentation strategy that is becoming increasingly popular in medical imaging. However, satisfying the requirements of higher accuracy and less running time is always a great challenge. In this paper we propose a novel patch-based segmentation method combining a local weighted voting strategy with Bayesian inference. Multiple atlases are registered to a target image by an advanced normalization tools(ANTs) algorithm. To obtain a segmentation of the target, labels of the atlas images are propagated to the target image. We first adopt intensity prior and label prior as two key metrics when implementing the local weighted voting scheme, and then compute the two priors at the patch level. Further, we analyze the label fusion procedure concerning the image background and take the image background as an isolated label when estimating the label prior. Finally, by taking the Dice score as a criterion to quantitatively assess the accuracy of segmentations, we compare the results with those of other methods, including joint fusion, majority voting, local weighted voting, majority voting based on patch, and the widely used Free Surfer whole-brain segmentation tool. It can be clearly seen that the proposed algorithm provides better results than the other methods. During the experiments, we make explorations about the influence of different parameters(including patch size, patch area, and the number of training subjects) on segmentation accuracy.

关键词： Label fusion Local weighted voting Patch-based Background analysis

Robust state-space realizations of digital filters against finite word length errors

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Journal of Systems Engineering and Electronics 2008年第5期19卷 896-901页

作者： He Xiongxiong Li Gang zhu Guangxin wan Chunru Coll. of Information Engineering Zhejiang Univ. of Technology Hangzhou 310014 P. R. China School of EEE Nanyang Technological Univ. Singapore 639798 Singapore

This article deals with two important issues in digital filter implementation： roundoff noise and limit cycles. A novel class of robust state-space realizations, called normal realizations, is derived and characterized. It is seen that these realizations are free of limit cycles. Another interesting property of the normal realizations is that they yield a minimal error propagation gain. The optimal realization problem, defined as to find those normal realizations that minimize roundoff noise gain, is formulated and solved analytically. A design example is presented to demonstrate the behavior of the optimal normal realizations and to compare them with several well-known digital filter realizations in terms of minimizing the roundoff noise and the error propagation.

关键词： digital signal processing digital filter structures optimal normal realizations finite word length,roundoff noise limit cycles.

Super-resolution image reconstruction based on three-step-training neural networks

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Journal of Systems Engineering and Electronics 2010年第6期21卷 934-940页

作者： Fuzhen zhu Jinzong Li Bing zhu Dongdong ma Institute of Image Information Technology and Engineering Harbin Institute of Technology Heilongjiang 150001 R R. China

A new method of super-resolution image reconstruction is proposed, which uses a three-step-training error backpropagation neural network （BPNN） to realize the super-resolution reconstruction （SRR） of satellite image. The method is based on BPNN. First, three groups learning samples with different resolutions are obtained according to image observation model, and then vector mappings are respectively used to those three group learning samples to speed up the convergence of BPNN, at last, three times consecutive training are carried on the BPNN. Training samples used in each step are of higher resolution than those used in the previous steps, so the increasing weights store a great amount of information for SRR, and network performance and generalization ability are improved greatly. Simulation and generalization tests are carried on the well-trained three-step-training NN respectively, and the reconstruction results with higher resolution images verify the effectiveness and validity of this method.

关键词： image reconstruction super-resolution three-steptraining neural network BP algorithm vector mapping.

Electromigration in eutectic SnAg solder reaction couples with various ambient temperatures and current densities

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International Journal of Minerals,Metallurgy and materials 2009年第6期16卷 685-690页

作者： Guang-chen Xu Fu Guo wan-rong zhu College of materials Science and Engineering Beijing University of Technology Beijing 100124 China

The electromigration behavior of eutectic SnAg solder reaction couples was studied at various temperature （25 and 120℃ when the current density was held constant at 104 A/cm^2 or 5×10^3 A/cm^2. Under the current density of 104 A/cm^2, scallop type Cu6Sn5 spalls and migrates towards the direction of electron flow at room ambient temperature （25℃）, but transforms to layer type Cu3Sn and leaves Kirkendall voids in it at high ambient temperature （120℃）. Under the current density of 5×10^3 A/cm^2 plus room ambient temperature, no obvious directional migration of metal atoms/ions is found. Instead, the thermal stress induced by mismatch of dissimilar materials causes the formation of superficial valley at both interfaces. However, when the ambient temperature increases to 120℃, the mobility of metal atoms/ions is enhanced, and then the grains rotate due to the anisotropic property of β-Sn.

关键词： electromigration eutectic solder Joule heating intermetallic compound

Streak camera calibration for bunch length measurement at BEPC II

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Radiation Detection Technology and Methods 2021年第3期5卷 466-473页

作者： wan Zhang Dechong zhu Yanfeng Sui Huizhou ma Junhui Yue Jianshe Cao Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039China

Purpose Streak camera is an important device for bunch length *** errors introduced by streak camera should be considered in *** order to accurately measure bunch length,some streak camera calibrations are studied at BEPC *** In this context,the point spread function,caused by the optical system,is measured at focus mode with both deflec-tions *** the same conditions,the influence of camera gain on measurement is *** the dual sweep mode of streak camera,a calibration method using electrical delays is applied to calibrate the beam size *** Firstly,a point spread function calibration 1.78 ps of streak camera optical system is obtained with focus ***,studying the effect of camera gain on measurement,an optimal camera gain range from 506 to 662 is selected,in which the bunch length measurement error is within 0.5 ***,a dual sweep calibration factor 1.02 is *** For BEPCII bunch length,there is a little difference before and after the streak camera ***,for the accurate measurement of ultra-short bunch length,the calibrations are of great significance.

关键词： Streak camera Point spread function Photon counts Dual sweep mode Bunch length measurement

Integrated optimization on aerodynamics-structure coupling and flight stability of a large airplane in preliminary design

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Chinese Journal of Aeronautics 2018年第6期31卷 1258-1272页

作者： Xiaozhe wanG Zhiqiang wan zhu LIU Chao YANG School of Aeronautic Science and Engineering Beihang University Key Laboratory of Aircraft Advanced Design Technology Ministry of Industry and Information

The preliminary phase is significant during the whole design process of a large airplane because of its enormous potential in enhancing the overall performance. However, classical sequential designs can hardly adapt to modern airplanes, due to their repeated iterations, long periods, and massive computational burdens. Multidisciplinary analysis and optimization demonstrates the capability to tackle such complex design issues. In this paper, an integrated optimization method for the preliminary design of a large airplane is proposed, accounting for aerodynamics, structure, and stability. Aeroelastic responses are computed by a rapid three-dimensional flight load analysis method combining the high-order panel method and the structural elasticity correction. The flow field is determined by the viscous/inviscid iteration method, and the cruise stability is evaluated by the linear small-disturbance theory. Parametric optimization is carried out using genetic algorithm to seek the minimal weight of a simplified plate-beam wing structure in the cruise trim condition subject to aeroelastic, aerodynamic, and stability constraints, and the optimal wing geometry shape, front/rear spar positions, and structural sizes are obtained simultaneously. To reduce the computational burden of the static aeroelasticity analysis in the optimization process, the Kriging method is employed to predict aerodynamic influence coefficient matrices of different aerodynamic shapes. The multidisciplinary analyses guarantee computational accuracy and efficiency, and the integrated optimization considers the coupling effect sufficiently between different disciplines to improve the overall performance, avoiding the limitations of sequential approaches utilized currently.

关键词： Aeroelasticity Integrated optimization Multidisciptinary analysis Large airplane Preliminary design

Modified Frequency Scaling Algorithm for FMCW SAR Data Processing

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Chinese Journal of Aeronautics 2007年第4期20卷 339-345页

作者： Jiang Zhihong Huang Fukan wan Jianwei Cheng zhu College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

This paper presents a modified frequency scaling algorithm for frequency modulated continuous wave synthetic aperture radar （FMCW SAR） data processing. The relative motion between radar and target in FMCW SAR during reception and between transmission and reception will introduce serious dilation in the received signal. The dilation can cause serious distortions in the reconstructed images using conventional signal processing methods. The received signal is derived and the received signal in range-Doppler domain is given. The relation between the phase resulting from antenna motion and the azimuth frequency is analyzed. The modified frequency scaling algorithm is proposed to process the received signal with serious dilation. The algorithm can effectively eliminate the impact of the dilation. The algorithm performances are shown by the simulation results.

关键词： FMCW radar SAR radar imaging frequency scaling algorithm

Advanced silicon nanostructures derived from natural silicate minerals for energy storage and conversion

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Green Energy & Environment 2022年第2期7卷 205-220页

作者： Hao wan Wei ma Kechao Zhou Yijun Cao Xiaohe Liu Renzhi ma School of Chemical Engineering Zhengzhou UniversityZhengzhou450001China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China International Center for materials Nanoarchitectonics(WPI-maNA) National Institute for Materials Science(NIMS)Namiki 1-1TsukubaIbaraki305-0044Japan

To effectively alleviate the ever-increasing energy crisis and environmental issues,clean and sustainable energy-related materials as well as the corresponding storage/conversion devices are in urgent ***(Si) with the second most elemental abundance on the crust in the form of silicate or silica(SiO_(2)) minerals,is an advanced emerging material showing high performance in energy-related fields(***,photocatalytic hydrogen evolution).For the improved performance in industry-scale applications,Si materials with delicate nanostructures and ideal compositions in a massive production are highly *** account of the reserve,low cost and diverse micro-nanostructures,silicate minerals are proposed as promising raw *** the article,crystal structures and the reduction approaches for silicate minerals,as well as recent progress on the as-reduced Si products for clean energy storage/conversion,are presented ***,some cutting-edge fields involving Si materials are discussed,which may offer deep insights into the rational design of advanced Si nanostructures for extended energy-related fields.

关键词： minerals massive silicate