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The generalization of a class of impulse stochastic control models of a geometric Brownian motion

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Science in China(Series F) 2009年第6期52卷 983-998页

作者： liu xiaopeng liu KunHui College of Science Beijing Jiaotong University Beijing 100044 China

Recently, international academic circles advanced a class of new stochastic control models of a geometric Brownian motion which is an important kind of impulse control models whose cost structure is different from the others before, and it has a broad applying background and important theoretical significance in financial control and management of *** paper generalizes substantially the above stochastic control models under quite extensive conditions and describes the models more exactly under more normal theoretical system of stochastic *** establishing a set of proper variational equations and proving the existence of its solution, and applying the means of stochastic analysis, this paper proves that the generalized stochastic control models have optimal ***, we also analyze the structure of optimal controls ***, we study the solution function of variational equations in a relatively deep-going way, which constitutes the value function of control models to some *** the analysis methods of this paper are greatly different from those of original reference, this paper possesses considerable originality to some *** addition, this paper gives the strict proof to the part of original reference which is not fairly well-knit in analyses, and makes analyses and discussions of the model have the exactitude of mathematical sense.

关键词： mpulse stochastic control geometric Brownian motion variational equation optimal control

Catalytic Performance of MFI/MFI Core-Shell Zeolites in Benzene Methylation

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China Petroleum Processing & Petrochemical Technology 2014年第4期16卷 94-99页

作者： Zhang Baozhong liu xiaopeng General Research Institute for Nonferrous Metals SINOPEC Tianjin Company

Thanks to its 10-membered-ring structure with a three-dimensional uniform pore system and acid distribution, ZSM-5 zeolite is a key catalytic material for benzene methylation with methanol. After epitaxial inter-growth of a dense layer of shell consisting of nano-particles on the conventional ZSM-5 crystal surface, the MFI/MFI core-shell zeolite not only has much more active surface area, but also can enrich the diffusion and reaction pore system at the same time, which can significantly improve its catalytic performance. In contrast to the performance of conventional ZSM-5 catalyst, an indepth investigation on the reaction parameters of benzene methylation over the core-shell structured zeolite is of great significance.

关键词： core-shell zeolite, methanol, benzene methylation, process parameters

Preparation of Al2O3/Y2O3 composite coating for deuterium permeation reduction

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Journal of Rare Earths 2020年第11期38卷 1237-1242,I0004页

作者： Weijing Wang Qinghe Yu xiaopeng liu Zheng Lu National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A tritium permeation barrier is required in fusion blankets for the reduction of fuel loss and radiological *** this study,an Al2O3/Y2O3 composite coating was prepared on 316 L stainless steel by radiofrequency magnetron sputtering in order to improve the tritium permeation *** microstructure and the phase composition of the Al2O3/Y2O3 composite coating are observed by scanning electron microscopy,transmission electron microscopy and grazing incidence X-ray ***,Auger electron spectroscopy was used to characterize the depth profiles of Al,Y and O *** results clearly indicate that the Al2O3/Y2O3 composite coating is fully dense and the total thickness is approximately 340 *** Al2O3/Y2O3 coating consists of an amorphous Al2O3 and the cubic Y2O3,in which Al,Y and O elements are homogeneously distributed in the vertical base ***,the deuterium permeation property of the Al2O3/Y2O3 composite coating was measured by the gas phase permeation *** results show that the introduction of an interface and the existence of a tiny amount of micro-defects improve the deuterium resistance of the Al2O3/Y2O3 coating,and its deuterium permeation reduction factor is 536-750 at 873-973 ***,it is concluded that the Al2O3/Y2O3 co mposite coating as deuterium permeation barrier can significa ntly enha nce the deuterium permeation resistance property.

关键词： Deuterium Permeation barrier Al2O3 coating Y2O3 coating Composite coating Rare earths

Research on Rare Earth Encapsulated Luminescent Material

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Journal of Rare Earths 2004年第z1期22卷 153-156页

作者： Yu Zhiwei liu Chengdong Qi xiaopeng Material Science and Engineering Department East China Institute of Technology Fuzhou Jiangxi 344000China Material Science and Engineering Department East China Institute of Technology Fuzhou Jiangxi 344000China Material Science and Engineering Department East China Institute of Technology Fuzhou Jiangxi 344000China

A new method of preparation of irradiative material by using rare earth as luminophor and inorganic powder as base nucleus was *** earth was used to make colloid, which was mixed with base nucleus solution,where deposition/attachment reaction took place and rare earth was adhered onto the surface of base nucleus, hence yielding a new rare earth encapsulated irradiative *** spectrum analysis shows that this material possesses two emission peaks, one within 400 ～ 500 nm and the other within 580 ～ 700 nm, reflecting the luminous characteristics of original rare earth material.

关键词： irradiative material fluorescent analysis rare earths

Hydrogen storage properties of Zr_(1-x)Ti_xCo intermetallic compound

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Rare Metals 2006年第z2期25卷 200-203页

作者： HUANG Zhuo liu xiaopeng JIANG Lijun WANG Shumao Energy Materials and Technology Research Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China Energy Materials and Technology Research Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China Energy Materials and Technology Research Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China Energy Materials and Technology Research Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China

The intermetallic compound Zr1-xTixCo was prepared and its suitability for hydrogen storage was investigated. The alloys obtained by magnetic levitation melting with the composition of Zr1-xTixCo (x=0, 0.1, 0.2 and 0.3, at.%) show single cubic phase by X-ray diffraction. A single sloping plateau was observed on each isothermal, and pressure-composition-temperature (PCT) measurement results show that the equilibrium hydrogen desorption pressure of Zr1-xTixCo alloy increases with increasing Ti content. The desorption temperatures for supplying 100 kPa hydrogen are about 665, 642, 621 and 614 K for ZrCo, Zr0.9Ti0.1Co, Zr0.8Ti0.2Co and Zr0.7Ti0.3Co alloy, respectively. Repeated hydrogen absorption and desorption cycles do not generate separated ZrCo, TiCo and ZrH2 phases, indicating that alloys have good thermal and hydrogen stabilization.

关键词： hydrogen storage alloy ZrCo intermetallic compound hydrogen isotope

Preparation and hydrogen sorption properties of Mg-Cu-Y-H systems

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Rare Metals 2006年第z2期25卷 89-94页

作者： LI Zhinian liu xiaopeng HUANG Zuo JIANG Lijun WANG Shumao Energy Materials and Technology Research Institute General Research Institute for Nonferrous MetalsBeijing 100088China

Mg-xwt.%CuY(x=15,20,25)composites were successfully prepared by reactive mechanical alloying(RMA).X-ray diffraction(XRD)measurement shows that main phases of the as milled composites are MgH_(2) and Mg_(2)Cu,and they converted into Mg and MgCu_(2) after dehydrogenation,***-Composition-Isotherm(PCI)test shows that the composites exhibit double pressure plateau at each isothermal desorption *** hydrogen absorption and desorption kinetics of the composites become worse with increasing x content,indicating that Mg-Cu phase has a negative effect on the hydrogen sorption properties of the *** is supposed that the good hydrogen sorption properties of the composites attribute to the catalyst effect of yttrium hydride distributed in Mg substrate and the particles size reduction and crystal defects formed by RMA.

关键词： hydrogen storage composite mechanical alloying Mg-Cu-Y-H system magnesium

Hydrogen sorption properties of Mg-20wt.%Fe_(23)Y_(8) composite prepared by reactive mechanical alloying

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Rare Metals 2006年第z1期25卷 247-251页

作者： LI Zhinian liu xiaopeng HUANG Zuo JIANG Lijun WANG Shumao Hydrogen Material&Technology Research Institute General Research Institute for Nonferrous MetalBeijing100088China

Mg-20wt.%Fe_(23)Y_(8) composite was successfully prepared by reactive mechanical alloying(RMA).X-ray diffraction(XRD)measurement shows that the main phases of composite are MgH_(2) and *** composite exhibits excellent hydrogen abs/desorption properties and can absorb 4.36wt.%and 5.72wt.%hydrogen at 473 and 573 K in 10 min under 3.0 MPa hydrogen pressure,*** composite can desorb 5.27wt.%hydrogen at 573 K in 30 min under 0.02 MPa hydrogen *** with the pure MgH_(2),the hydrogen desorption temperature of Mg-20wt.%Fe_(23)Y_(8) composite is decreased about 40℃.It is supposed that both the catalyst effect of Fe-Y distributed in Mg substrate and the crystal defects play the main role in improving hydrogen sorption properties of Mg-20wt.%Fe_(23)Y_(8) composite.

关键词： hydrogen storage composite magnesium mechanical alloying P-C-T and Mg_(2)FeH_(6)

Influencing Factors and Prediction of Risk of Returning to Ecological Poverty in liupan Mountain Region,China

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Chinese Geographical Science 2024年第3期34卷 420-435页

作者： CUI Yunxia liu xiaopeng JIANG Chunmei TIAN Rujun NIU Qingrui School of Geography and Planning Ningxia UniversityYinchuan 750021China Key Laboratory(China-Arab)of Resource Evaluation and Environmental Regulation of Arid Region in Ningxia Yinchuan 750021China

China has resolved its overall regional poverty in 2020 by attaining moderate societal *** country has entered a new development stage designed to achieve its second centenary ***,ecological fragility and risk susceptibility have increased the risk of returning to ecological *** this paper,the liupan Mountain Region of China was used as a case study,and the counties were used as the scale to reveal the spatiotempora differentiation and influcing factors of the risk of returning to poverty in study *** indicator data for returning to ecological poverty from 2011-2020 were collected and summarized in three dimensions:ecological,economic and *** autoregressive integrated moving average model(ARIMA)time series and exponential smoothing method(ES)were used to predict the multidimensional indicators of returning to ecological poverty for 61 counties(districts)in the liupan Mountain Region for *** back propagation neural network(BPNN)and geographic information system(GIS)were used to generate the spatial distribution and time variation for the index of the risk of returning to ecological poverty(RREP index).The results show that 1)ecological factors were the main factors in the risk of returning to ecological poverty in liupan Mountain Region.2)The RREP index for the 61 counties(districts)exhibited a downward trend from *** RREP index declined more in medium-and high-risk areas than in low-risk *** 2021 to 2025,the RREP index exhibited a slight downward *** 2026 to2030,the RREP index was expected to decline faster,especially from 2029-2030.3)Based on the RREP index,it can be roughly divided into three types,namely,the high-risk areas,the medium-risk areas,and the low-risk *** natural resource conditions in lowrisk areas of returning to ecological poverty,were better than those in medium-and high-risk areas.

关键词： risk of returning to ecological poverty autoregressive integrated moving average model(ARIMA) exponential smoothing model back propagation neural network(BPNN) liupan Mountain Region,China

The enhanced protective effects of salvianic acid A: A functionalized nanoparticles against ischemic stroke through increasing the permeability of the blood-brain barrier

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Nano Research 2020年第10期13卷 2791-2802页

作者： Yaru Li Xiaojie Zhang Zhifeng Qi Xueling Guo xiaopeng liu Wenjuan Shi Yang liu Libo Du State Key Laboratory for Structural Chemistry of Unstable and Stable Species Center for Molecular ScienceInstiute of ChemistryChinese Academy of SciencesBeijing 100190China Graduate School University of Chinese Academy of SciencesBejing 100049China Cerebrovascular Diseases Research Institute Xuanwu Hospital of Captital Medical UniversityBeijing 100053China Department of Neurosurger The Second Hospial of Hebei Medical UniversityShijazhuang 050051China

Ischemic stroke is the leading cause of disability and death worldwide. Currently, the only proven treatment for ischemic stroke is restoring the cerebral blood supply. In addition, some of the tissue is damaged during the subsequent reperfusion because of the overproduction of reactive oxygen species (ROS). Furthermore, antioxidant therapies have shown promise in preclinical studies for the treatment of ischemia-reperfusion injury. However, their therapeutic efficacy has been limited because of their low bioavailability in brain. To resolve this issue, we synthesized ROS-responsive, fan-shaped dendrimer nanoparticles (NPs) and conjugated them with a blood-brain barrier (BBB)-targeting peptide, COG1410, and salvianic acid A (SA), which is an effective antioxidant in ischemic stroke. The BBB targeting peptide acts as a ligand of the nanocarrier system and penetrates the BBB through the endocytosis of the ligand receptor. The results showed that T-SA-NPs not only target and accumulate in the infarct area, they also reduce over 2 times of the infarct area and reverse the behavioral deficits in MCAO mice, which illustrates that these NPs have an effective therapeutic effect on the ischemic stroke. In addition, these NPs had no toxicity in any organs of the body. Importantly, the present study provides an alternative strategy for delivering antioxidants to the brain and achieving targeted therapy of ischemic stroke.

关键词： ischemic stroke blood-brain barrier salvianic acid A COG1410 reactive oxygen species(ROS)-responsive nanocarrier mitophagy