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Polymer-to-Monomers Chemically Recyclable Poly(imide-imine)Plastics with Extreme-Condition Resistance and Flame Retardancy

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Chinese Journal of Polymer Science 2024年第10期42卷 1525-1535,I0012页

作者： zhen-yu wang Xiao-Kong Liu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun130012China

Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of ***,it is of great significance to develop recyclable polyimides with comparable properties to the commercial ***,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-CR-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine *** PtM-CR-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial *** PtM-CR-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile strength as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-CR-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic ***,the cyclophosphazene moieties endow the PtM-CR-PII plastic with excellent flame *** PtM-CR-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-CR-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high *** recovered pure monomers can be used to regenerate new PtM-CR-PII plastics,enabling sustainable polymer-monomers-polymer circulation.

关键词： Chemical recyclability Polyimides Polyimines Dynamic imine bonds Mechanical properties Chemical stability

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FACTORS INFLUENCING THERMAL STRUCTURE IN A TRIBUTARY BAY OF THREE GORGES RESERVOIR

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Journal of Hydrodynamics 2011年第4期23卷 407-415页

作者： yu zhen-zhen wang Ling-ling College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China

To better understand the factors influencing the thermal structure of tributaries in the Three Gorges Reservoir （TGR）, a well validated three-dimensional hydrodynamic and water temperature model was proposed to simulate the water temperature distribution in the Xiangxi Bay, a representative tributary of TGR. The numerical results show that water temperature stratification seasonally occurred in the Xiangxi Bay, with stable vertical temperature profiles. It is found from the numerical experiments that three key factors are responsible for the formation of water temperature structure：（1） very often, the locations of thermocline are mainly determined by wind speeds, and the higher the wind speed is, the deeper the thermocline is located beneath the water surface, which could be expressed by a fitted exponential function, （2） the thermal structure is affected by static stability of water column, and the thermocline becomes closer to the water surface and its thickness increases with the increase of temperature, （3） due to the effect of the thermal density inflow, the water temperature of the hypolimnion tends to be uniform, however, even under the condition of larger inflow discharge, the influence of the inflow on the epilitnnion and the thermocline is not significant.

关键词： water temperature stratification numerical simulation density current influencing factors wind force static stability of water inflow discharge Three Gorges Reservoir (TGR)

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Regional Stability of Positive Switched Linear Systems with Multi-equilibrium Points

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International Journal of Automation and computing 2017年第2期14卷 213-220页

作者： Zhi Liu yu-zhen wang School of Control Science and Engineering Shandong University Ji'nan 250061 China

This paper studies the regional stability for positive switched linear systems with multi-equilibrium points （PSLS-MEP）. First, a sufficient condition is presented for the regional stability of PSLS-MEP via a common linear Lyapunov function. Second, by establishing multiple Lyapunov functions, a dwell time based condition is proposed for the regional stability analysis. Third, a suprasphere which contains all equilibrium points is constructed as a stability region of the considered PSLS-MEP, which is less conservative than existing results. Finally, the study of an illustrative example shows that the obtained results are effective in the regional stability analysis of PSLS-MEP.

关键词： Regional stability positive switched linear system multi-equilibrium points common linear Lyapunov function multipleLyapunov function.

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Dual protective role of HO-1 in transplanted liver grafts:A review of experimental and clinical studies

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World Journal of Gastroenterology 2011年第26期17卷 3101-3108页

作者： Chun-Feng wang zhen-yu wang Ji-yu Li Department ofGeneral Surgery Xinhua Hospital School of Medicine ShanghaiJiao Tong University Shanghai 200092 China

Liver transplantation is considered as the most effective treatment for end-stage liver ***,serious complications still exist,particularly in two aspects:ischemia and subsequent reperfusion of the liver,causing postoperative hepatic dysfunction and even failure;and acute and chronic graft rejections,affecting the allograft *** oxygenase(HO),a stressresponse protein,is believed to exert a protective function on both the development of ischemia-reperfusion injury(IRI) and graft *** this review of current researches on allograft protection,we focused on the *** conjecture that HO-1 may link these two main factors affecting the prognosis of liver *** this review,the following aspects were emphasized:the basic biological functions of HO-1,itsroles in IRI and allograft rejection,as well as methods to induce HO-1 and the prospects of a therapeutic application of HO-1 in liver transplantation.

关键词： Liver transplantation Heme oxygenase-1 AIIograft rejection Ischemia/reperfusion injury

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Discrete element modeling of sand behavior in a biaxial shear test

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第9期9卷 1176-1183页

作者： Zhi-yi HUANG Zhong-xuan YANG zhen-yu wang Department of Civil Engineering Zhejiang University Hangzhou 310027 China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang University Hangzhou 310027 China Department of Civil Engineering The University of Hong Kong Hong Kong China

The mechanical behavior of sand is very complex, and depends on factors including confining pressure, density, and drainage condition. A soil mass can be contractive or dilative when subjected to shear loading, and eventually reaches an ultimate state, referred to as the critical state in soil mechanics. Conventional approach to explore the mechanical behavior of sand mainly relies on the experimental tests in laboratory. This paper gives an alternative view to this subject using discrete element method (DEM), which has attracted much attention in recent years. The implementation of the DEM is carried out by a series of numerical tests on granular assemblies with varying initial densities and confining pressures, under different test configurations. The results demonstrate that such numerical simulations can produce correct responses of the sand behavior in general, including the critical state response, as compared to experimental observations. In addition, the DEM can further provide details of the microstructure evolutions during shearing processes, and the resulting induced anisotropy can be fully captured and quantified in the particle scale.

关键词： Granular soil behavior Critical state Microstructure Discrete element method (DEM)

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Preserving qubit coherence by dynamical decoupling

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Frontiers of physics 2011年第1期6卷 2-14页

作者： Wen YANG zhen-yu wang Ren-Bao LIU Department of Physics University of California San Diego La Jolla CA 92093-0319 USA Department of Physics The Chinese University of Hong Kong Shatin N. T. Hon9 Kong China

In quantum information processing, it is vital to protect the coherence of qubits in noisy environments. Dynamical decoupling （DD）, which applies a sequence of flips on qubits and averages the qubit-environment coupling to zero, is a promising strategy compatible with other desired functionalities, such as quantum gates. Here, we review the recent progresses in theories of dynamical decoupling and experimental demonstrations. We give both semiclassical and quantum descriptions of the qubit decoherence due to coupling to noisy environments. Based on the quantum picture, a geometrical interpretation of DD is presented. The periodic Carr Purcell-Meiboom-Gill DD and the concatenated DD are reviewed, followed by a detailed exploration of the recently developed Uhrig DD, which employs the least number of pulses in an unequally spaced sequence to suppress the qubit-environment coupling to a given order of the evolution time. Some new developments and perspectives are also discussed.

关键词： qubit decoherence dynamical decoupling

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A Bi-Functional Xyloglucan Galactosyltransferase Is an Indispensable Salt Stress Tolerance Determinant in Arabidopsis

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Molecular Plant 2013年第4期6卷 1344-1354页

作者： Wenbo Li Qingmei Guan zhen-yu wang Yingdian wang Jianhua Zhu College of Life Sciences Beijing Normal University Beijing 100875 China Department of Plant Science and Landscape Architecture University of Maryland College Park MD 20742 USA Center for Plant Stress Genomics and Technology King Abdullah University of Science and Technology Thuwal 23955-6900 Kingdom of Saudi Arabia

Salinity is an abiotic stress that substantially limits crop production worldwide. To identify salt stress tolerance determinants, we screened for Arabidopsis mutants that are hypersensitive to salt stress and designated these mutants as short root in salt medium （rsa）. One of these mutants, rsa3-1, is hypersensitive to NaCI and LiCI but not to CsCI or to general osmotic stress. Reactive oxygen species （ROS） over-accumulate in rsa3-1 plants under salt stress. Gene expression profiling with Affymetrix microarray analysis revealed that RSA3 controls expression of many genes including genes encoding proteins for ROS detoxification under salt stress. Map-based cloning showed that RSA3 encodes a xyloglucan galactosyltransferase, which is allelic to a gene previously named MUR3/KAM1. The RSA3/ MUR3/KAMl-encoded xylogluscan galactosyltransferase regulates actin microfilament organization （and thereby con- tributes to endomembrane distribution） and is also involved in cell wall biosynthesis. In rsa3-1, actin cannot assemble and form bundles as it does in the wild-type but instead aggregates in the cytoplasm. Furthermore, addition of phal- Ioidin, which prevents actin depolymerization, can rescue salt hypersensitivity of rsa3-1. Together, these results sug- gest that RSA3/MUR3/KAM1 along with other cell wall-associated proteins plays a critical role in salt stress tolerance by maintaining the proper organization of actin microfilaments in order to minimize damage caused by excessive ROS.

关键词： salt stress tolerance xyloglucan galactosyltransferase endomembranes actin microfilaments RSA3.

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Robust H_∞ Filter Design for Time-delay Systems with Saturation

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International Journal of Automation and computing 2013年第4期10卷 368-374页

作者： Xiao-Fang Hong yu-zhen wang Hai-Tao Li School of Control Science and Engineering Shandong University Department of Electrical and Automation Shandong Labor Vocational and Technical College

This paper investigates the H∞ filtering problem for a class of linear continuous-time systems with both time delay and saturation. Such systems have time delay in their state equations and saturation in their output equations, and their process and measurement noises have unknown statistical characteristics and bounded energies. Based on the Lyapunov-Krasovskii stability theorem and the linear matrix inequalities （LMIs） technique, a generalized dynamic filter architecture is proposed, and a filter design method is developed. The linear H∞ filter designed by the method can guarantee the H∞ performance. The parameters of the designed filter can be obtained by solving a kind of LMI. An illustrative example shows that the design method proposed in this paper is very effective.

关键词： H∞ filter saturation time delay nonlinear system linear matrix inequality.

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Crack Properties of Lean Duplex Stainless Steel 2101 in Hot Forming Processes

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Journal of Iron and Steel Research International 2011年第4期18卷 58-62页

作者： FANG Yi-liu LIU zhen-yu wang Guo-dong State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

The crack behavior of LDX 2101 by hot compression tests in the temperature range of 950 to 1150 ℃ and strain rate range of 0.01 to 30 s-1 was *** hot workability map of LDX 2101 was constructed and the alloy exhibited a better crack resistance at higher temperature and lower strain *** initiated and coalesced into crack at subsurface on the equatorial plane of bulge surface under secondary tensile *** cracks were orientated at an angle of approximately 45° with respect to the compression axis due to the secondary tensile *** easily initiated on the interface of ferrite and austenite and propagated within *** predicted results using specific plastic work approach were matched well with the free surface cracks.

关键词： lean duplex stainless steel hot workability crack specific plastic work approach

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Development of a PC-based Open Architecture Software-CNC System

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Chinese Journal of Aeronautics 2007年第3期20卷 272-281页

作者： MA Xiong-bo HAN zhen-yu wang Yong-zhang FU Hong-ya School of Electromechanical Engineering Harbin Institute of Technology Harbin 150001 China

As a key te..hnology in the field of advanced manufacturing, an open architecture controller is studied. In order to develop an open architecture software-CNC system on personal computer （PC） according to open modular architecture controllers （OMAC）. First, the software and hardware platform is chosen and software realization methodology for the CNC system is determined. Second, static modeling methods of an open architecture controller inclusive of object-oriented （OO） programming technology, dynamic link library （DLL） technology and system modules partition are investigated. Third, the dynamical behavioral modeling and the data flow representation of open architecture controller are discussed, which are both described in hierarchy fmite state machine （FSM） model. Fourth, a reusable software module model is established to develop software function module library. Finally, a 3-axis milling machine tool test-bed, named for HIT-CNC, is successfully designed by means of the constructed software function module library and the system configuring method. The experimental results show that, besides increasing the degree of reusability and openness, application of above-mentioned method- ology leads to significant decrease of development time as well as maintenance cost.

关键词： open architecture controller PC soflware-CNC behavioral model OMAC machine tool

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