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Regularity of the Density for the Total Weighted Occupation Measure of Super-Brownain Motion

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Acta Mathematica Sinica,English Series 2011年第8期27卷 1557-1572页

作者： rong li liu Department of Mathematics Nanjing University Nanjing 210093 P. R. China

Let （Xt） be a super-Brownian motion in a bounded domain D in R^d. The random measure Y^D（.） = ∫o^∞ Xt（.）dt is called the total weighted occupation time of （Xt）. We consider the regularity properties for the densities of a class of yD. When d = 1, the densities have continuous modifications. When d ≥ 2, the densities are locally unbounded on any open subset of D with positive y D （dx）-measure.

关键词： Superprocesses Poisson point processes regularity total weighted occupation time

Role of platelet-activating factor in pathogenesis of acute pancreatitis

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World Journal of Gastroenterology 2006年第4期12卷 539-545页

作者： li-rong liu Shi-Hai Xia Department of Gastroenterology Pancreas Center of Affiliated Hospital of Medical College of the Chinese People's Armed Police Forces Tianjin 300162 China

Platelet-activating factor(PAF)is a potentproinflammatory phospholipid mediator that belongsto a family of biologically active,structurally relatedalkyl phosphoglycerides with diverse pathologicaland physiological *** bioactive phospholipidmediates processes as diverse as wound healing,physiological inflammation,angiogenesis,apoptosis,reproduction and long-term *** actsby binding to a specific G protein-coupled receptorto activate multiple intracellular signaling *** most cells both synthesize and release PAFand express PAF receptors,PAF has potent biologicalactions in a broad range of cell types and *** activation of this signaling pathway isassociated with many diseases in which inflammationis thought to be one of the underlying ***(AP)is a common inflammatory *** onset of AP is pancreatic autodigestion mediatedby abnormal activation of pancreatic enzyme caused bymultiple agents,which subsequently induce pancreaticand systemic inflammatory reactions.A number ofexperimental pancreatitis and clinical trials indicatethat PAF does play a critical role in the pathogenesisof *** of PAF receptor antagonist cansignificantly reduce local and systemic events that occurin *** review focuses on the aspects that are morerelevant to the pathogenesis of AP.

关键词： Platelet-activating factor Signal transduction Pancreatitis Pathogenesis

Effects of Dendritic Orientation on Stress Rupture Properties of DD6 Single Crystal Superalloy

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Journal of Iron and Steel Research International 2011年第10期18卷 66-71页

作者： SHI Zhen-xue li Jia-rong liu Shi-zhong ZHAOJin-qian National Key Laboratory of Science and Technology on Advanced High Temperature Structural Materials Beijing Institute of Aeronautical Materials Beijing 100095 China

DD6 single crystal superalloy slabs were prepared with seed method in the direetionally solidified furnace with high temperature gradient. The transverse stress rupture properties and fracture hehaviour of the alloy at 760 ℃/758 MPa, 850 ℃/550 MPa and 980 ℃/250 MPa were investigated and compared with those of longitudinal specimens. The transverse stress rupture lives are corresponding with the longitudinal stress rupture lives at 760 ℃/758 MPa and 850 ℃/550 MPa. The transverse stress rupture lives are slightly less than the longitudinal stress rupture lives at 980 ℃/ 250 MPa. The fracture mechanism of the transverse stress rupture of the alloy at 760 ℃/758 MPa shows quasi-cleav- age mode and the fracture mechanism at 980 ℃/250 MPa shows dimple mode, while the fracture mechanism at 850 ℃/ 550 MPa shows quasi-cleavage and dimple mixture mode. At higher temperature and lower stress, the microeracks are easier to initiate and interconnect in the transverse specimen than those in longitudinal specimen because there are interdendritic regions perpendicular to the axis of stress.

关键词： DD6 single crystal superalloy stress rupture property fracture behaviour

Effect of long-term thermal exposure on microstructure and creep properties of DD5 single crystal superalloy

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China Foundry 2021年第3期18卷 185-191页

作者： Xu-dong Wang Zhong Yang Qiang Gao li-rong liu School of Materials and Chemical Engineering Xi’an Technological UniversityXi’an 710021China Fugu County Xuli Mechanical and Electrical Technology Co. Ltd.Yulin 719499China School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

The effect of thermal exposure on the microstructure and creep properties of the Ni-based single crystal superalloy in different test conditions was ***-term exposure was performed at 1,000 ℃ and 1,100 ℃ for 500 h prior to the creep *** creep lifetime is found to be improved after the long-term exposure at 1,000 ℃ for 500 h as a result of the formation of secondary M_(23)C_(6) in the interdendritic *** coarsening of γ’ precipitates accompanied by the formation of TCP phase lead to the degradation of alloy,which is responsible for the reduction of the creep lifetime of Ni-base single crystal superalloy after long-term exposure at 1,100 ℃ for 500 *** creep lifetime of 1,000 oC thermally exposed sample under the conditions of 1,093 ℃/137 MPa is lower than that of heat-treated *** exposure at 1,100 ℃ for 500 h causes the creep lifetime to drop drastically.

关键词： long-term thermal exposure microstructure creep properties Ni-based single crystal superalloy M_(23)C_(6)carbide

Dysprosium Modification of Cobalt Ferrite Ionic Magnetic Fluids

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Journal of China University of Mining and Technology 2005年第4期15卷 354-356页

作者： JIANG rong-li liu Yong-chao GENG Quan-rong ZHAO Wen-tao School of Chemical Engineering and Technology China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

Dysprosium composite cobalt ferrite ionic magnetic fluids were prepared by precipitation in the presence of Tri-sodium citrate. Influence of dysprosium modification on magnetic property is studied. The result shows that magnetic response toward exterior magnetic field can be improved by adding Dy3+. Studies also show that the increase of reaction temperature may improve the modification effect of dysprosium. By adding dysprosium ions, the average diameter of the magnetic nanoparticles will be decreased evidently. It is clear that the particles appear as balls. Cobalt ferrite with sizes of 12-15 nm, rare earth composite cobalt ferrite with sizes of 6-8 nm.

关键词： cobalt ferrite magnetic fluids dysprosium modification mechanism magnetic property

Effect of sintering temperature on microstructure and properties of 3D printing polysilazane reinforced Al_(2)O_(3)core

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China Foundry 2023年第5期20卷 387-394页

作者： Wen-jun Dong Qiao-lei li Tian-ci Chen Ming-ke Zou Jing-jing liang li-rong liu Hui Mei Jin-guo li School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Space Manufacturing Technology(CAS Key Lab) Beijing 100094China Science and Technology on Thermostructural Composite Materials Laboratory School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China

Ceramic cores are the key intermediate components of hollow blades for *** processes,such as hot-press molding and gel film casting,face difficulties in fabricating complex-structured ceramic cores due to the complexity of moulds and long process *** 3D printing provides a new idea for the fabrication of complex-structured ceramic *** effect of sintering temperature on open porosity,bulk density,weight loss rate,shrinkage rate,flexural strength and microstructure of the Al_(2)O_(3)-based ceramic core doped with 10vol.%polysilazane(PSZ)was *** sintering mechanism of PSZ-reinforced ceramic cores was *** show that the optimum sintering temperature of PSZ-reinforced ceramic cores is 1,450°*** this temperature,the open porosity of the ceramic core is 36.60%,bulk density is 2.33 g·cm^(-3),weight loss rate is 22.11%,shrinkage rate along the X,Y,Z directions is 5.72%,5.01%,9.61%,respectively;the flexural strength is 28.794 MPa at 25°C and 13.649 MPa at 1,500°*** of 3D printing PSZ-reinforced ceramic cores can meet the casting requirement of superalloy hollow blades,which is expected to promote the industrial application of 3D printing complex structure ceramic cores.

关键词： investment casting ceramic core 3D printing sintering temperature flexural strength

Evolution of interfacial dislocation networks during long term thermal aging in Ni-based single crystal superalloy DD5

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China Foundry 2019年第1期16卷 14-22页

作者： Qiang Gao li-rong liu Xiao-hua Tang Zhi-jiang Peng Ming-jun Zhang Su-gui Tian School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China AECC Shenyang liming Aero Engine Co.Ltd. Shenyang 110043China

Interfacial dislocations found in single crystal superalloys after long term thermal aging have an important effect on mechanical properties. Long term thermal aging tests for DD5 single crystal superalloy were carried out at 1,100 ℃ for 20, 100, 200, 500 and 1000 h, and then cooled by air. The effect of long term thermal aging on the dislocation networks at the γ/γ' interfaces was investigated by FE-SEM. Results showed that during the long term thermal aging at 1,100 ℃, misfit dislocations formed firstly and then reorientation in the(001) interfacial planes occurred. Different types of square or rectangular dislocation network form by dislocation reaction. Square dislocation networks consisting of four groups of dislocations can transform into octagonal dislocation networks, and then form another square dislocation network by dislocation reaction. Rectangular dislocation networks can also transform into hexagonal dislocation networks. The interfacial dislocation networks promote the γ' phase rafting process. The dislocation networks spacings become smaller and smaller, leading to the effective lattice misfit increasing from-0.10% to-0.32%.

关键词： DD5 single crystal superalloy interfacial dislocations long term thermal aging effective lattice misfit

Immune Responses of Chicken Immunizedwith Marek's Disease Vaccines

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Journal of Northeast Agricultural University(English Edition) 1996年第1期3卷 29-37页

作者： liu Zhonggui, Gao rong,li Qingzhang,liu Yun, Zheng Shimin,Yan liping(Northeast Agricultural University,Harbin,150030 PR China)

The experiment was conducted to study the dynamic changes of immune responses of chicks immunized with March's disease(MD)trivalent vaccine and turkey herpesvirus(HVT)at one day *** were found that after immunization of chicks with MD vaccines,the intcrlcukinc-2(IL-2)inductive activity and IL-2 receptor expression of T cells from thymus and spleen significantly increased,suggesting that the immunoregulativc function was markedly enhanced in the immune organs;the number of antibody-producing cells,the number and proliferative function of T cells rose markedly in Bursa Fabricius,spleen and thymus,indicating that the cellular and humoral immune responses were elevated remarkablly in the central and peripheral immune organs;the number of T and antibody-producing cells as well as the content of IgG,IgA and IgM obviously mounted in cecal tonsil, Harder tan gland mucosal lymphoid tissues of bronchus along with tears,trachea washings, bile and intestinal fluids,demonstrating that the local and mucosal immunity was raised in the respiratory and digestive tract;the levels of immune responses mentioned above in the trivalent vaccine-immuniaed chicks were apparently higher than those of HVT-immunized birds.

关键词： Marek's vaccination chick immune responses

Effect of Long-Term Thermal Exposures on Tensile Behaviors of K416B Nickel-Based Superalloy

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Acta Metallurgica Sinica(English Letters) 2020年第12期33卷 1699-1708页

作者： Mao-Kai Chen Jun Xie De-Long Shu Gui-Chen Hou Shu-ling Xun Jin-Jiang Yu li-rong liu Xiao-Feng Sun Yi-Zhou Zhou Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Shenyang University of Technology Shenyang 110870China

The effect of long-term thermal exposure on the tensile behavior of a high W content nickel-based superalloy K416B was *** microstructure and the deformation characteristics were observed by scanning electron microscopy and transmission electron microscopy,and the phase transformation of the alloy during long-term thermal exposure was analyzed by X-ray diffraction patterns and differential thermal *** showed that after thermal exposure at 1000℃,the MC carbides in the K416 B alloy decomposed into M_(6)*** tensile deformation,dislocations slipping inγmatrix crossed over the M_(6)C by Orowan bowing *** the increase of thermal exposure time,the secondary M_(6)C reduced greatly the yield strength of the alloy at room ***,the continuous distribution of the secondary M_(6)C with great brittleness in the grain boundary could become the main source of crack,which might change the fracture characteristic of the alloy from trans-granular to intergranular.

关键词： K416B superalloy Thermal exposure Deformation mechanism Fracture characteristics