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Further Results on Delay-distribution-dependent Robust Stability Criteria for Delayed Systems

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International Journal of Automation and computing 2011年第1期8卷 23-28页

作者： jian-jiang yu School of Information Science and Technology Yancheng Teachers University Yancheng 224002 PRC

This paper concerns the robust stability analysis of uncertain systems with time delays as random variables drawn from some probability distribution. The delay-distribution-dependent criteria for the exponential stability of the original system in mean square sense are achieved by Lyapunov functional method and the linear matrix inequality （LMI） technique. The proposed approach involves neither free weighting matrices nor any model transformation, and it shows that the new criteria can provide less conservative results than some existing ones. Numerical examples are given to demonstrate the effectiveness and the benefits of the proposed method.

关键词： Delay-distribution-dependent robust stability stochastic time delay time-varying delay linear matrix inequality (LMI).

Formation mechanisms and sequence response of authigenic grain-coating chlorite: evidence from the Upper Triassic Xujiahe Formation in the southern Sichuan Basin, China

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Petroleum Science 2016年第4期13卷 657-668页

作者： yu yu Liang-Biao Lin jian Gao State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology Institute of Sedimentary Geology Chengdu University of Technology

Authigenic grain-coating chlorite is widely distributed in the clastic rocks of many sedimentary basins around the world. These iron minerals were mainly derived from flocculent precipitates formed when rivers flow into the ocean, especially in deltaic environments with high hydrodynamic conditions. At the same time, sandstone sequences with grain-coating chlorites also tend to have relatively high glauconite and pyrite content. EPMA composition analysis shows that glauconites with ‘‘high Al and low Fe’’ content indicate slightly to semi-saline marine environments with weak alkaline and weakly reducing conditions. By analyzing the chlorite-containing sandstone bodies of the southern Sichuan Xujiahe Formation, this study found that chlorite was mainly distributed in sedimentary microfacies, including underwater distributary channels, distributary channels, shallow lake sandstone dams, and mouth bars. Chlorite had a tendency to form in the upper parts of sandstone bodies with signs of increased base level, representing the influence of marine（lacustrine）transgression. This is believed to be influenced by megamonsoons in the Middle and Upper Yangtze Region during the Late Triassic Epoch. During periods of abundant precipitation, river discharges increased and more Fe particulates flowed into the ocean（lake）. In the meantime,increases or decreases in lake level were only affected byprecipitation for short periods of time. The sedimentary environment shifted from weakly oxidizing to weak alkaline, weakly reducing conditions as sea level increased, and Fe-rich minerals as authigenic chlorite and glauconite began to form and deposit.

关键词： Sichuan Basin Xujiahe Formation Graincoating chlorite Glauconite Pyrite

Steel-refractory reactions in lanthanum-,cerium-,and ytrium-added steels

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Journal of Iron and Steel Research International 2024年第6期31卷 1473-1485页

作者： jian Kang Hong-po Wang yu Wang College of Materials Science and Engineering Chongqing UniversityChongqing 400044China The State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China

A systematic experimental study was conducted on the similarities and differences in the reactions between commonly used rare earth elements(REEs)and frequently used refractories in the steelmaking *** results indicate that the reaction behaviors of La,Ce,and Y with MgO,Al_(2)O_(3),and MgO·Al_(2)O_(3) crucibles differed *** consumption rates of La,Ce,and Y in the molten steel were in descending order of La>Ce>Y for smelting with all three kinds of *** the REEs reacted with the crucible,the contents of Mg and Al showed a trend of first increasing and then *** laboratory-scale smelting conditions,the reactions related to REEs were dominated by steel-crucible reactions,and the contact area between the unit mass of molten steel and refractory materials mainly determined the consumption rates of ***-and Ce-crucible reactions generated loose and porous reaction interfaces;however,Y-crucible reactions generated a dense Y_(2)O_(3) layer,dramatically suppressing the consumption rate of *** calculation indicated that the reactions between rare earth and different refractory materials were first-order *** crucible materials significantly affected the product type and morphology of the steel-crucible reaction interfaces,thereby influencing the consumption rate of *** reactions between REEs and refractories must be seriously considered,especially for small-scale smelting.

关键词： Rare earth Inclusion Refractory Thermodynamics Dynamics

tuning Surface Molecular Design of Porous Carbon for Blue Energy Harvesting

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Research 2024年第1期2023卷 651-662页

作者： jian yu Zhong-Lin Wang Tianwei Ma Department of Civil and Environmental Engineering University of Hawaii at MānoaHonoluluHI 96822USA Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China College of Engineering Texas A&M University-Corpus ChristiCorpus ChristiTX 78412USA

Capacitive mixing is a promising blue energy technology due to its membrane-free electricity generation and long electrode life ***,because of limited performance,existing systems do not lend themselves to practical *** it is a crucial factor directly influencing electrode behavior,surface chemistry has largely been overlooked in capacitive ***,we show that manipulating surface functionalization alone can tune the responses of electrodes to produce a high voltage rise without altering the pore structure of the *** findings reveal that the spontaneous electrode potential of a surface-modified carbon electrode shifts negatively proportional to the surface charge due to the surface groups,which explains why and how manipulating the surface chemistry can improve the power generation capacity.

关键词： electrode Porous mixing

A regeneratable dynamic differential evolution algorithm for neural networks with integer weights

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第12期11卷 939-947页

作者： jian BAO yu CHEN Jin-shou yu School of lnformation Science and Engineering East China Universi~ of Science and Technology Shanghai 200237 China Institute of Sofrtware and Intelligent Technology Hangzhou Dianzi University Hangzhou 310018 China

Neural networks with integer weights are more suited for embedded systems and hardware implementations than those with real weights. However, many learning algorithms, which have been proposed for training neural networks with float weights, are inefficient and difficult to train for neural networks with integer weights. In this paper, a novel regeneratable dynamic differential evolution algorithm (RDDE) is presented. This algorithm is efficient for training networks with integer weights. In comparison with the conventional differential evolution algorithm (DE), RDDE has introduced three new strategies: (1) A regeneratable strategy is introduced to ensure further evolution, when all the individuals are the same after several iterations such that they cannot evolve further. In other words, there is an escape from the local minima. (2) A dynamic strategy is designed to speed up convergence and simplify the algorithm by updating its population dynamically. (3) A local greedy strategy is introduced to improve local searching ability when the population approaches the global optimal solution. In comparison with other gradient based algorithms, RDDE does not need the gradient information, which has been the main obstacle for training networks with integer weights. The experiment results show that RDDE can train integer-weight networks more efficiently.

关键词： Differential evolution Integer weights Neural networks Greedy Embedded systems Function approximation

Discerning Weld Seam Pro les from Strong Arc Background for the Robotic Automated Welding Process via Visual Attention Features

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Chinese Journal of Mechanical Engineering 2020年第1期33卷 170-181页

作者： Yinshui He Zhuohua yu jian Li Lesheng yu Guohong Ma School of Environment and Chemical Engineering Nanchang UniversityNanchang 330031China School of Mechanical Engineering Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi ProvinceNanchang UniversityNanchang 330031China Institute of Technology.East China Jiao Tong University Nanchang 330100China

In the robotic welding process with thick steel plates,laser vision sensors are widely used to profile the weld seam to implement automatic seam *** weld seam profile extraction(WSPE)result is a crucial step for identifying the feature points of the extracted profile to guide the welding torch in real *** visual information processing system may collapse when interference data points in the image survive during the phase of feature point identification,which results in low tracking accuracy and poor welding *** paper presents a visual attention featurebased method to extract the weld seam profile(WSP)from the strong arc background using clustering ***,a binary image is obtained through the preprocessing ***,all data points with a gray value 255 are clustered with the nearest neighborhood clustering ***,a strategy is developed to discern one cluster belonging to the WSP from the appointed candidate clusters in each loop,and a scheme is proposed to extract the entire WSP using visual *** with the previous methods the proposed method in this paper can extract more useful details of the WSP and has better stability in terms of removing the interference *** WSPE tests with butt joints and T-joints show the anti-interference ability of the proposed method,which contributes to smoothing the welding process and shows its practical value in robotic automated welding with thick steel plates.

关键词： Weld seam profile extraction Visual attention features Clustering Robotic welding

Removal of dichloromethane from waste gases by a biotrickling filter

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Journal of Environmental Sciences 2006年第6期18卷 1073-1076页

作者： yu jian-ming CHEN jian-meng WANG Jia-de College of Biological and Environmental Engineering Zhejiang University of Technology Hangzhou 310032 China

Dichloromethane is harmful to human health and hazardous to atmospheric environment. In this study, two strains were isolated which were identified as Pseudomonas sp. and Mycobacterium sp., and utilized dichloromethane （DCM） as sole carbon and energy sources. The optimal culture conditions were temperature of 28℃ and pH of 6.5 for obtaining the two mixed bacterial strains. The investigation on the purification of DCM-contaminated gas was carried out in a bench-scale biotrickling filter which was inoculated with the two strains and operated under these optimal conditions. The DCM removal efficiencies varied between 72% and 99% in the biotrickling filter when empty-bed residence time was 9.6 s with the inlet concentrations ranged fi＇om 0.7 to 3.12 g/m^3 under the conditions ofpH of 6.5 ±0.5 and temperature of 28℃. It was also found that NaCl accumulation in the broth would inhibit the DCM biodegradation dramatically when the accumulated NaCl concentration was over 35.1 g/L.

关键词： dichloromethane biodegradation biotrickling filter air pollution control

Transverse relaxation characteristic and stress relaxation model considering molecular chains of HTPB coating based on pre-strained thermal aging

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Defence Technology（防务技术） 2021年第3期17卷 821-828页

作者： Yong-qiang Du jian Zheng Gui-bo yu jian-zhuang Zhi Shijiazhuang Campus Army Engineering UniversityShijiazhuang050003China Intelligent Manufacturing Institute Hebei College of Industry and TechnologyShijiazhuang050003China

In order to accurately describe the transverse relaxation characteristic and stress relaxation modulus of HTPB coating during pre-strain thermal aging process,a one month thermal aging test was carried out at70C with pre-strain of 0%,3%,6%and 9%,*** low-field1 H NMR and stress relaxation modulus tests were carried out for HTPB coating at different aging *** stress relaxation model considering the molecular chains was proposed according to the changes of crosslinking chain and dangling chain of HTPB coating during pre-strain *** results showed that with the increase of aging time,the decay rate of transverse relaxation curve became faster,the transverse relaxation time decreased,the value of combined parameter q Mrl increased,the proportion of crosslinking chain decreased,while the proportion of dangling chain ***,the stress relaxation modulus increased,the crosslinking network structure of HTPB coating became denser and the degree of crosslinking *** the initial aging stage,the pre-strain will destroy the crosslinking network structure of HTPB coating to a certain *** the increase of aging time,the effect of pre-strain will gradually weaken and the influence of aging on materials will gradually *** correlations between the stress relaxation model considering the molecular chains and the test results were more than 0.9950,which can accurately describe the stress relaxation modulus of HTPB coating during the pre-strain thermal aging process.

关键词： HTPB Pre-strain aging Transverse relaxation characteristic Molecular chain Stress relaxation model

HMFI分子筛Bronsted酸性位点与碱性分子的作用机制

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原子与分子物理学报 2025年第4期42卷 1-7页

作者：郑健秦康秦玉才宋丽娟中石化石油化工科学研究院有限公司北京100083 辽宁石油化工大学辽宁省石油化工催化科学与技术重点实验室抚顺113001

采用密度泛函理论(DFT)方法,以单铝、双铝和三铝酸性位点HMFI分子筛为模型分子筛,计算去质子化能考察HMFI分子筛的本征酸性,以NH_(3)分子作为模型分子,计算NH_(3)分子在HMFI分子筛中的吸附能与去质子化能进行关联性分析,并进一步考察NH_... 详细信息

采用密度泛函理论(DFT)方法,以单铝、双铝和三铝酸性位点HMFI分子筛为模型分子筛,计算去质子化能考察HMFI分子筛的本征酸性,以NH_(3)分子作为模型分子,计算NH_(3)分子在HMFI分子筛中的吸附能与去质子化能进行关联性分析,并进一步考察NH_(3)分子与HMFI分子筛的作用机制.研究表明分子筛Bronsted酸(简称B酸)强度与B酸数量没有强相关性,在考虑B酸位数量的同时须考虑B酸位的分布.酸性位点数量和分布的差异均可以调控NH_(3)分子的吸附构象,并且可以通过调节HMFI分子筛孔道对分子施加相互作用的模式,解析分子的结构和电子性质,精准调控分子的进一步转化.此项工作可以为未来高效多孔材料有效物种活性位的构建提供新思路.

关键词：密度泛函理论 HMFI分子筛 Bronsted酸性质吸附性能