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| 1 | Theoretical analyses and numerical experiments of variational assimilation for one-dimensional ocean temperature model with techniques in inverse problems显示文摘In the present work, the data assimilation problem in meteorology and physical oceanography is re-examined using the variational optimal control approaches in combination with regularization techniques in inverse problem. Here the estimations of the initial condition, boundary condition and model parameters are performed simultaneously in the framework of variational data assimilation. To overcome the difficulty of ill-posedness, especially for the model parameters distributed in space and time, an additional term is added into the cost functional as a stabilized functional. Numerical experiments show that even with noisy observations the initial conditions and model parameters are recovered to an acceptable degree of accuracy. | HUANG Sixun1,2, HAN Wei1 & WU Rongsheng2 1. P. O. Box 003, Nanjing 211101,China 2. Key Laboratory of Meso-Scale Severe Weather /MOE, Department of Atmospheric Sciences, Nanjing University, Nanjing 210093, China Correspondence should be addressed to Huang Sixun | 2004 | Science China Earth Sciences2004，47，7： | 18 |
| 2 | Statistical estimations of atmospheric duct over the South China Sea and the Tropical Eastern Indian Ocean显示文摘In 2010-2012 spring, atmospheric duct observation experiments were performed throughout three open cruises over the South China Sea and the Tropical Eastern Indian Ocean. The data used for ducting analysis were measured by high resolution balloon-borne GPS radiosondes. Through data quality control and diagnostic analysis, the probability of ducting occurrence and characteristic quantities of the three typical ducts were given. The total percentage occurrence of evaporation duct, surface-based duct and elevated duct were 75.3%, 5% and 43.7%, respectively. The mean evaporation duct height was 15.3 m. The mean values of duct height, thickness and magnitude were 84.1 m, 14.9 m and 10 M-units for surfaced-based duct, and 1003.6 m, 62.2 m and 7.9 M-units for elevated duct. These preliminary statistical results can serve as a basis for future comprehensive and comparative studies of atmospheric duct for the research region. | ZHAO XiaoFeng WANG DongXiao HUANG SiXun HUANG Ke CHEN Ju | 2013 | Chinese Science Bulletin2013，58，23： | 16 |
| 3 | Formation of Poly(ε-caprolactone) Networks via Supramolecular Hydrogen Bonding Interactions显示文摘In this contribution, we reported a novel approach to crosslink poly(ε-caprolactone)(PCL) via supramolecular hydrogen bonding interactions. First, a series of octa-armed poly(ε-caprolactone) stars with polyhedral oligomeric silsesquioxane(POSS) cores were synthesized via the ring-opening polymerizations. Thereafter, the arm ends of organic-inorganic star-shaped PCLs were reacted with 2-(6-isocyanatohexylaminocarbonylamino)-6-methyl-4[1 H]-pyrimidinone to obtain 2-ureido-4[1 H]-pyrimidone(UPy)-terminated PCL stars.Notably, the UPy-terminated PCL stars were physically crosslinked, which was evidenced by means of dynamic mechanical thermal analysis(DMTA) and rheological analysis. Owing to the formation of the physically-crosslinked networks, the organic-inorganic PCL stars displayed significant shape memory properties with about 100% of shape recovery, which was in marked contrast to the PCL stars without UPy termini. | Sen Xu Pengfei Chang Bingjie Zhao Muhammad Adeel Sixun Zheng | 2019 | Chinese Journal of Polymer Science2019，37，3： | 5 |
| 4 | Sufficient conditions of Rayleigh-Taylor stability and instability in equatorial ionosphere显示文摘Rayleigh-Taylor(R-T) instability is known as the fundamental mechanism of equatorial plasma bubbles(EPBs). However, the sufficient conditions of R-T instability and stability have not yet been derived. In the present paper, the sufficient conditions of R-T stability and instability are preliminarily derived. Linear equations for small perturbation are first obtained from the electron/ion continuity equations, momentum equations, and the current continuity equation in the equatorial ionosphere. The linear equations can be casted as an eigenvalue equation using a normal mode method. The eigenvalue equation is a variable coefficient linear equation that can be solved using a variational approach. With this approach, the sufficient conditions can be obtained as follows: if the minimum systematic eigenvalue is greater than one, the ionosphere is R-T unstable; while if the maximum systematic eigenvalue is less than one, the ionosphere is R-T stable. An approximate numerical method for obtaining the systematic eigenvalues is introduced, and the R-T stable/unstable areas are calculated. Numerical experiments are designed to validate the sufficient conditions. The results agree with the derived sufficient conditions. | Sicheng WANG Sixun HUANG | 2016 | Applied Mathematics and Mechanics(English Edition)2016，37，2： | 2 |
| 5 | Evolution of atmospheric corrosion of MnCuP weathering steel in a simulated coastal-industrial atmosphere显示文摘 | Long Hao Sixun Zhang Junhua Dong Wei Ke | 2012 | Corrosion Science2012，，： | 2 |
| 6 | Osteosarcoma cell proliferation and migration are partly regulated by redox-activated NHE-1显示文摘Background:Osteosarcoma(OS)is the most common primary malignant bone tumor in children and adolescents.OS is associated with locally aggressive growth and high metastatic potential.The mechanisms that underlie these processes are currently elusive.Reactive oxygen species(ROS)and Na+/H+exchanger 1(NHE1)have been suggested to regulate proliferation and migration of tumor cells.However,the relationship between NHE1 and ROS in OS proliferation and migration has not been investigated before.Aim:To investigate the role of NHE1 and ROS in the proliferation and migration of OS.Methods:ROS levels and NHE1 expression were studied in cultured human OS cells and human OS xenografts in nude mice.In vitro,OS cells were treated with different doses of tert-butyl hydroperoxide(tBHP),a ROS inducer,and cariporide,an NHE1 inhibitor,to study the effect on cell proliferation and migration.In vivo,nude mice bearing OS cells were administrated with NHE1 inhibitor or antioxidant and the tumor weights were measured.Results:This study reported for the first time that the expression of NHE1 and intracellular ROS level were both increased in OS tissues and cells.Exposure of OS cell to ROS derived from tBHP was able to accelerate cell proliferation and migration and also up-regulate NHE1 protein expression.Moreover,tBHP significantly increased intracellular pH(pHi),decreased extracellular pH(pHe)and induced upregulation of ERK,MMP2,and MMP9.Lowering of ROS levels with the anti-oxidant DMTU or inhibiting NHE1 activity via cariporide abolished the stimulatory effect of tBHP.However,there cariporide did not affect intracellular ROS levels.In vivo study we further confirmed that cariporide could inhibit tumor growth in the nude mouse xenografts of OS cells.Conclusions:The data demonstrate that up-regulation of NHE1 was induced by low concentrations of ROS contributes to the regulation of tumor proliferation and invasion of OS.Relevance for patients:There is potential application for cariporide as an effective antitumor agent during the development of human osteosarcoma.In addition,redox modulation on proton transport may represent a novel target of osteosarcoma prevention,and open a new avenues for future research. | Hua Bai Guojing Chen Congwen Fang Xuekang Yang Sixun Yu Chunxu Hai | 2015 | Journal of Clinical & Translational Research2015，1，3： | 2 |
| 7 | Epoxy nano- composites with octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane 显示文摘 | Liu Yonghong Zheng Sixun Nie Kangming | 2005 | Polymer2005，46，12： | 1 |
| 8 | Poly(4-vinylpyridine) nanocrosslinked by polyhedral oligomeric silsesquioxane显示文摘 | Liu Yonghong Meng Fanliang Zheng Sixun | 2005 | Macromolecular Rapid Communication2005，26，11： | 1 |
| 9 | Gerneralized method of variational analysis for 3-D hlow显示文摘 | Lan Weiren Huang Sixun | 2004 | Adv Atmos Sci2004，21，5： | 1 |
| 10 | Block Copolymer Networks Composed of Poly(ε-caprolactone) and Polyethylene with Triple Shape Memory Properties显示文摘In this contribution, we reported a novel synthesis of block copolymer networks composed of poly(ε-caprolactone)(PCL) and polyethylene(PE) via the co-hydrolysis and condensation of α,ω-ditriethoxylsilane-terminated PCL and PE telechelics. First, α,ω-dihydroxylterminated PCL and PE telechelics were synthesized via the ring-opening polymerization of ε-caprolactone and the ring-opening metathesis polymerization of cyclooctene followed by hydrogenation of polycyclooctene. Both α,ω-ditriethoxylsilane-terminated PCL and PE telechelics were obtained via in situ reaction of α,ω-dihydroxyl-terminated PCL and PE telechelics with 3-isocyanatopropyltriethoxysilane. The formation of networks was evidenced by the solubility and rheological tests. It was found that the block copolymer networks were microphase-separated. The PCL and PE blocks still preserved the crystallinity. Owing to the formation of crosslinked networks, the materials displayed shape memory properties. More importantly, the combination of PCL with PE resulted that the block copolymer networks had the triple shape memory properties, which can be triggered with the melting and crystallization of PCL and PE blocks. The results reported in this work demonstrated that triple shape memory polymers could be prepared via the formation of block copolymer networks. | Honggang Mei Bingjie Zhao Yuan Gao Lei Li Liyue Liu Sixun Zheng | 2022 | Chinese Journal of Polymer Science2022，40，2： | 1 |
| 11 | High-pressure DSCstudy of thermal transition of a poly(ethylene terephthalate)/carbon dioxide system显示文摘 | Zhikai Zhong Sixun Zheng Yongli Mi | 1999 | Polymer1999，40，： | 1 |
| 12 | Reaction-induced microphase separation in thermosetting blends of epoxy resin with poly(methyl methacrylate)- block -polystyrene block copolymers: Effect of topologies of block copolymers on morphological structures显示文摘 | Wenchun Fan Sixun Zheng | 2008 | Polymer2008，，13： | 1 |
| 13 | Synthesis, characterization, and controllable drug release of dendritic star-block copolymer by ring-opening polymerization and atom transfer radical polymerization显示文摘 | Weizhong Yuan Jinying Yuan Sixun Zheng Xiaoyin Hong | 2007 | Polymer2007，，9： | 1 |
| 14 | Montmorillonite Intercalated by Ammonium of Octaaminopropyl Polyhedral Oligomeric Silsesquioxane and Its Nanocomposites with Epoxy Resin显示文摘 | Liu Hongzhi Zhang Weian Zheng Sixun | 2005 | Polymer2005，46，1： | 1 |
| 15 | Hepta(3,3,3-trifluoro- propyl) polyhedral oligomeric silsesquioxane-capped poly(N- isopropylacrylamide) telechelies: Synthesis and behavior of physical hydrogels 显示文摘 | Wang Lei Zeng Ke Zheng Sixun | 2011 | ACS Appl Mater Interf2011，，3： | 1 |
| 16 | Montmorillonite Intercalated by Ammonium of Octaaminopropyl Polyhedral Oligomeric Silsesquioxane and its Nanocom- posites with Epoxy Resin显示文摘 | Liu Hongzhi Zhang Weian Zheng Sixun | 2005 | Polymer2005，46，1： | 1 |
| 17 | An improved QuikSCAT wind retrieval algorithm and eye locating for typhoon显示文摘This paper proposes a rain considered geophysical model function (GMF), to be noted as GMF plus Rain. GMF plus Rain is based on the basic raidative transfer model with attenuation and scattering effects of rain on radar signal considered. Combined with the NSCAT2 GMF and the rain correction model, the GMF plus Rain model is used to retrieve the ocean wind vectors from the collocated QuikSCAT and SSM/I rain rate data for typhoon Melor. The resulting wind speed estimates of typhoon Melor show improved agreement with the wind fields derived from the best track analysis of Japan Meteorological Agency (JMA). The results imply that compared with the GMF model, the GMF plus Rain model can improve the precision of wind retrieval under the rain condition. Then, a new general algorithm of locating the eye of typhoon through the normalized radar cross section (NRCS) is proposed. The implementation of this algorithm in the ten QuikSCAT observations of typhoon Melor suggests that this algorithm is effective. | ZHONG Jian FEI Jianfang HUANG Sixun DU Huadong ZHANG Liang | 2012 | Acta Oceanologica Sinica2012，31，1： | 1 |
| 18 | Inorganiceorganic interpenetrating polymer networks involving polyhedral oligomeric silsesquioxane and poly(ethylene oxide) 显示文摘 | Mu Jiangfeng Liu Yonghong Zheng Sixun | 2007 | Polymer2007，48，： | 1 |
| 19 | AMS radiocarbon dating of the Fengxi site in Shaanxi, China显示文摘 | Guo Zhiyu Liu Kexin Yuan Sixun | 2005 | Radiocarbon2005，47，2： | 1 |
| 20 | Retrieval of Eddy Thermal Conductivity in the Weakly Nonlinear Prandtl Model for Katabatic Flows显示文摘'Because the nonlinearity of actual physical processes can be expressed more precisely by the introduction of a nonlinear term, the weakly nonlinear Prandtl model is one of the most effective ways to describe the pure katabatic flow(no background flow). Features of the weak nonlinearity are reflected by two factors: the small parameter and the gradually varying eddy thermal conductivity. This paper first shows how to apply the Wentzel–Kramers–Brillouin(WKB) method for the approximate solution of the weakly nonlinear Prandtl model, and then describes the retrieval of gradually varying eddy thermal conductivity from observed wind speed and perturbed potential temperature.Gradually varying eddy thermal conductivity is generally derived from an empirical parameterization scheme. We utilize wind speed and potential temperature measurements, along with the variational assimilation technique, to derive this parameter. The objective function is constructed by the square of the differences between the observation and model value. The new method is validated by numerical experiments with simulated measurements, revealing that the order of the root mean squre error is 10^(–2) and thus confirming the method's robustness. In addition, this method is capable of anti-interference, as it effectively reduces the influence of observation error. | Bing YAN Sixun HUANG Jing FENG | 2017 | Journal of Meteorological Research2017，31，5： | 1 |
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