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Science China(Physics,Mechanics & Astronomy) 2012年第9期55卷 1679-1690页

作者： zhang junhua zhang Wei College of Mechanical Engineering Beijing University of Technology Beijing 100124 China

By using an extended Melnikov method on multi-degree-of-freedom Hamiltonian systems with perturbations,the global bifurcations and chaotic dynamics are investigated for a parametrically excited,simply supported rectangular buckled thin *** formulas of the rectangular buckled thin plate are derived by using the von Karman type *** two cases of the buckling for the rectangular thin plate are *** the aid of Galerkin's approach,a two-degree-of-freedom nonautonomous nonlinear system is obtained for the non-autonomous rectangular buckled thin *** high-dimensional Melnikov method developed by Yagasaki is directly employed to the non-autonomous ordinary differential equation of motion to analyze the global bifurcations and chaotic dynamics of the rectangular buckled thin *** method is used to find the chaotic responses of the non-autonomous rectangular buckled thin *** results obtained here indicate that the chaotic motions can occur in the parametrically excited,simply supported rectangular buckled thin plate.

关键词： extended high-dimensional Melnikov method rectangular buckled thin plate non-autonomous nonlinear system chaotic motions

Clinical research of traditional Chinese medicine in big data era

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Frontiers of Medicine 2014年第3期8卷 321-327页

作者： junhua zhang Boli zhang Tianjin University of Traditional Chinese Medicine Tianjin 210029 China China Academy of Chinese Medical Sciences Beijing 100700China

With the advent of big data era, our thinking, technology and methodology are being transformed. Data-intensive scientific discovery based on big data, named ＂The Fourth Paradigm,＂ has become a new paradigm of scientific research. Along with the development and application of the Internet information technology in the field of healthcare, individual health records, clinical data of diagnosis and treatment, and genomic data have been accumulated dramatically, which generates big data in medical field for clinical research and assessment. With the support of big data, the defects and weakness may be overcome in the methodology of the conventional clinical evaluation based on sampling. Our research target shifts from the ＂causality inference＂ to ＂correlativity analysis.＂ This not only facilitates the evaluation of individualized treatment, disease prediction, prevention and prognosis, but also is suitable for the practice of preventive healthcare and symptom pattern differentiation for treatment in terms of traditional Chinese medicine （TCM）, and for the post-marketing evaluation of Chinese patent medicines. To conduct clinical studies involved in big data in TCM domain, top level design is needed and should be performed orderly. The fundamental construction and innovation studies should be strengthened in the sections of data platform creation, data analysis technology and big-data professionals fostering and training.

关键词： big data traditional Chinese medicine clinical evaluation evidence based medicine

DETECTING COMMUNITY STRUCTURE： FROM PARSIMONY TO WEIGHTED PARSIMONY

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Journal of Systems Science & Complexity 2010年第5期23卷 1024-1036页

作者： junhua zhang Yuqing QIU Xiang-Sun zhang Key Laboratory of Random Complex Structures and Data Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Community detection has attracted a great deal of attention in recent years. A parsimony criterion for detecting this structure means that as minimal as possible number of inserted and deleted edges is needed when we make the network considered become a disjoint union of cliques. However, many small groups of nodes are obtained by directly using this criterion to some networks especially for sparse ones. In this paper we propose a weighted parsimony model in which a weight coefficient is introduced to balance the inserted and deleted edges to ensure the obtained subgraphs to be reasonable communities. Some benchmark testing examples are used to validate the effectiveness of the proposed method. It is interesting that the weight here can be determined only by the topological features of the network. Meanwhile we make some comparison of our model with maximizing modularity Q and modularity density D on some of the benchmark networks, although sometimes too many or a little less numbers of communities are obtained with Q or D, a proper number of communities are detected with the weighted model. All the computational results confirm its capability for community detection for the small or middle size networks.

关键词： Cliques community detection complex networks parsimony.

Multi-scale strength analysis of bolted connections used in integral thermal protection system

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Chinese Journal of Aeronautics 2018年第8期31卷 1728-1740页

作者： Heng LIANG Yuqing WANG Mingbo TONG junhua zhang College of Aerospace Engineering Ministerial Key Discipline Laboratory of Advanced Design Technology of Aircraft Nanjing University of Aeronautics & Astronautics Nanjing 210016 China Shanghai Aircraft Design and Research Institute Shanghai 201210 China

Efficient and accurate strength analysis of bolted connections is essential in analyzing the integral thermal protection system（ITPS） of hypersonic vehicles, since the system bears severe loads and structural failures usually occur at the connections. Investigations of composite mechanical properties used in ITPS are still in progress as the architecture of the composites is complex. A new method is proposed in this paper for strength analysis of bolted connections by investigating the elastic behavior and failure strength of three-dimensional C/C orthogonal composites used in ITPS. In this method a multi-scale finite element method incorporating the global–local method is established to ensure high efficiency in macro-scale and precision in meso-scale in *** results reveal that predictions of material properties show reasonable accuracy compared with test results. And the multi-scale method can analyze the strength of connections efficiently and accurately.

关键词： Bolted connection Composite Multi-scale method Strength analysis Thermal Protection System

Predicting lean blow-off of bluffbody stabilized flames based on Damkohler number

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Chinese Journal of Aeronautics 2019年第2期32卷 308-323页

作者： Zhonghao WANG Bin HU Aiming DENG junhua zhang Qingjun ZHAO Institute of Engineering Thermophysics Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Light-duty Gas-turbine Chinese Academy of Sciences

Lean Blow-Off(LBO) prediction is important to propulsion system design. In this paper,a hybrid method combining numerical simulation and Da(Damk?hler) model is proposed based on bluffbody stabilized flames. In the simulated reacting flow, Practical Reaction Zone(PRZ) is built based on OH radical concentration, and it is considered to be the critical zone that controls *** number is obtained based on the volume-averaged parameters of PRZ. The flow time scale(s_f)indicates the residence time of the fresh mixture flowing through the PRZ. It is obtained based on the characteristic length and volume-averaged axial velocity of the PRZ. The chemical time scale(s_c) indicates the shortest time needed to trigger the reaction of the mixture. It is obtained by commercial software CHEMKIN through monitoring the transient variation of the reactor temperature. The result shows that the average Da number under different LBO conditions is 1.135(the Da number under each LBO condition ranges from 0.673 to 1.351). This indicates that the flow time scale and chemical time scale are comparable. The combustion is in a critical state where LBO is easy to occur. With the increase of the fuel mass flow rate(the global fuel/air ratio increases from 0.004761 to 0.01095), s_f increases from 0.001268 s to 0.007249 s, and s_c decreases from 0.00124 s to0.00089 s. Accordingly, Da number increases from 1.023 to 8.145, which shows that the combustion becomes more stable. The above results show that the method proposed in the present study can properly predict the LBO limits of combustors, which provides important technical supports for combustor design and optimization.

关键词： Bluffbody stabilized flames Damkohler number Hybrid method LBO Time scales

Distribution patterns of SOC/TN content and their relationship with topography,vegetation and climatic factors in China’s north-south transitional zone

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Journal of Geographical Sciences 2022年第4期32卷 645-662页

作者： zhang junhua ZHU Lianqi LI Guodong ZHAO Fang QIN Jingting Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions(Henan University) Ministry of EducationKaifeng 475004HenanChina College of Geography and Environmental Science Henan UniversityKaifeng 475004HenanChina

The spatial distributions and variation mechanism of key soil indices in the Qinling-Daba Mountains are important indicators for the identification of the transitional effect and regional characteristics of the north–south transitional zone in *** manuscript analyzes the spatial variations in soil organic carbon(SOC)and total nitrogen(TN)and corresponding relationships with major geographical factors based on spatial analysis and geostatistics considering data obtained from the Second National Soil *** results indicate that the spatial distributions of the SOC and TN contents are consistent,and three high-content areas,one secondary high-content area and one low-content area are *** content values are located in the high-altitude regions of the Qinling-Daba Mountains and mountainous areas to the west of the Jialing River,the low-content area occurs on the north slope of the Qinling Mountains,and the secondary high-content area mainly encompasses both sides of the Hanjiang River and regions in the Qinling-Daba Mountains at altitudes below 1000 *** SOC and TN contents vary between the above two ranges,with the gradual increase in content revealing a horn-shaped *** the spatial variations and functions of vegetation,topography and climate factors,it is found that the SOC/TN range in the secondary high-content area remains consistent along the 1000 m contour line,the upper limit of the transitional mountain altitudinal belt,the 0℃isotherm line in January and the 24℃isotherm line in *** region constitutes the main body of the transitional zone between the subtropical and warm temperate zones,and the northern boundary is roughly distributed along the Dujiangyan-Maoxian-Pingwu-Wenxian line to the west of the Jialing River and the 1000 m contour line on the southern slope of the Qinling Mountains,while the southern boundary occurs along the Dujiangyan-Beichuan-Qingchuan line to the west of the Jialing River and the 1000 m cont

关键词： China’s north-south transitional zone SOC/TN distribution terrains mountain altitudinal belts climatic elements

Study on the interfacial shear behavior of steel reinforced concrete （SRC） members with stud connectors after fire

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Frontiers of Structural and Civil Engineering 2014年第2期8卷 140-150页

作者： Zihua zhang junhua LI Lei zhang Kai YU College of Civil Engineering and Environment Ningbo University Ningbo 315211 China

Statically push-out tests of 20 steel reinforced concrete short columns （SRCSC） with stud connectors on the surface of shape steel after fire and two SRCSC under ambient temperature were carried out, in order to study the failure mode, load-slip relationship and the interfacial shear transfer of SRC members after fire. Experimental results show that the typical failure modes and load-slip curves of SRCSC after fire are almost the same as the case under ambient temperature. The interfacial shear transfer of SRCSC declines exponentially not only with the increase of the peak temperature the specimen experienced but also with the increase of the peak temperature duration. The interfacial shear transfer of the specimens with studs arranged at the steel web is much higher than those with studs arranged at the steel flange. Empirical formulas of SRCSC interfacial shear transfer after fire are proposed, and the calculated results generally agree well with the experimental results.

关键词： steel reinforced concrete (SRC) short column stud connector afcer fire interfacial shear transfer

Spatial variation and driving mechanism of soil organic carbon components in the alluvial/sedimentary zone of the Yellow River

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Journal of Geographical Sciences 2021年第4期31卷 535-550页

作者： LI Guodong zhang junhua ZHU Lianqi TIAN Huiwen SHI Jiaqi REN Xiaojuan Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions(Henan University) Ministry of EducationKaifeng 475004HenanChina College of Environment and Planning Henan UniversityKaifeng 475004HenanChina

Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower *** Kaifeng and Zhoukou as typical cases of the Yellow River flooding area,the field survey,soil sample collection,laboratory experiment and Geographic Information System(GIS)spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil *** results revealed that the soil total organic carbon(TOC),active organic carbon(AOC)and nonactive organic carbon(NOC)contents ranged from 0.05–30.03 g/kg,0.01–8.86 g/kg and 0.02–23.36 g/kg,*** TOC,AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer,and the sequence of the content and change range within a single layer was TOC>NOC>*** analysis indicated that the TOC,AOC and NOC contents were commonly influenced by structural and random factors,and the influence magnitudes of these two factors were *** overall spatial trends of TOC,AOC and NOC remained relatively consistent from the 0–20 cm layer to the 20–100 cm layer,and the transition between high-and low-value areas was obvious,while the spatial variance was *** AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation *** distribution and depth of the sediment,agricultural land-use type,cropping system,fertilization method,tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon(SOC)***,increasing the organic matter content,straw return,applying organic manure,adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.

关键词： soil organic carbon Yellow River sediment spatial variation driving mechanism cultivation history

Development of Methylene Bis-Benzotriazolyl Tetramethylbutylphenol-grafted lignin sub-microspheres loaded with TiO_(2) for sunscreen applications

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Journal of Bioresources and Bioproducts 2024年第4期9卷 534-547页

作者： Yarong Li Zhiguang Tang Xiaohan Zhou junhua zhang Xueping Song Kai Li Wei Liu Zhanying zhang College of Light Industry and Food Engineering Guangxi UniversityNanning530004China Province and Ministry Co-Sponsored Collaborative Innovation Center of Cane Sugar Industry Nanning530004China Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources College of Chemical EngineeringNanjing Forestry UniversityNanjing210037China Guangxi Key Laboratory of Clean Pulp&Papermaking and Pollution Control Nanning530004China Tianjin Key Laboratory of Pulp&Paper Tianjin University of Science&TechnologyTianjin300457China School of Mechanical Medical and Process EngineeringCentre for Agriculture and the BioeconomyQueensland University of TechnologyQueensland4000Australia

Lignin serves as a promising Ultraviolet(UV)absorber within sunscreen ***,the commercial development of lignin-containing sunscreens faces challenges due to their low sun protection factor(SPF)and dark color in cosmetics *** this study,dual modifications on the chemical and physical structures of lignin were conducted to address these ***,methylene bis-benzotriazolyl tetramethylbutylphenol(MBBT)was grafted onto alkali lignin(AL)through an atom transfer radical polymerization reaction,resulting in a polymer of AL-graft-MBBT_(3)(AL-g-MBBT_(3)).The sunscreen prepared with 10%AL-g-MBBT_(3) displays outstand-ing sun protection performance with a SPF of 42.93 and a light color with a color difference value(ΔE)of 45.6,in contrast to 10%AL with a SPF of 4.74 and aΔE value of ***,AL-g-MBBT_(3) was transformed into normal submicron spheres(AL-g-MBBT_(3) N)and TiO_(2)-loading submicron spheres(AL-g-MBBT_(3)/TiO_(2)).The sun protection performances of 10%AL-g-MBBT_(3) N@C and AL-g-MBBT_(3)/TiO_(2)@C sunscreens obviously surpass that of AL-g-MBBT_(3)@C sunscreen,achieving SPFs of 60.38 and 66.20,***,there is a considerable improve-ment in the color of these sunscreens,withΔE values of 41.8 and 36.3,*** results provide valuable insights into exploring lignin’s high-value applications in sunscreen.

关键词： Lignin Graft Submicron sphere TiO_(2) Anti-UV performance Color

One pot synthesis of N-ethylaniline from nitrobenzene and ethanol

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Science China Chemistry 2008年第3期51卷 248-256页

作者： LI XiaoNian zhang junhua XIANG YiZhi MA Lei zhang QunFeng LU ChunShan WANG Hong BAI Ying Resources&Environment Catalysis Institute of Zhejiang University of Technology State Key Laboratory Breeding Base of Green Chemistry Synthesis TechnologyHangzhou 310032China

A novel method for the one pot synthesis of N-alkyl arylamines from nitro aromatic compounds and alcohols is proposed through the combination of the aqueous-phase reforming of alcohol for hydrogen production, the reduction of nitro aromatic compounds for the synthesis of aromatic amine and the N-alkylation of aromatic amine for the production of N-alkyl arylamine over an identical catalyst under the same conditions of temperature and pressure in a single reactor. In this process, hydrogen generated from the aqueous-phase reforming of alcohols was used in-situ for the hydrogenation of nitro aromatic compounds for aromatic amine synthesis, followed by N-alkylation of aromatic amine with alcohols to form the corresponding N-alkyl arylamines at a low partial pressure of hydrogen. For the system composed of nitrobenzene and ethanol, under the conditions of 413 K and PN2 = 1 MPa, the conversion degrees of nitrobenzene and aniline were 100%, the selectivity to N-ethylaniline and N, N-diethylaniline were 85.9% and 0%-4%, respectivity, after reaction for 8 h at the volumetric ratio of nitrobenzene:ethanol:water = 10:60:0. The selectivity for N, N-diethylaniline production is much lower than that through the traditional method. In this process, hydrogen and aromatic amines generated from the aqueous-phase reforming of alcohols and hydrogenation of nitro aromatic compounds, respectively, could be promptly removed from the surface of the catalyst due to the occurrence of in-situ hydrogenation and N-alkylation reactions. Thus, this may be a potential approach to increase the selectivity to N-alkyl arylamine.

关键词： nitrobenzene ethanol one pot N-ethylaniline combination N-alkylation Raney Ni