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硅铝溶胶混合黏结剂的稳定性及其催化性能的研究

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石化技术与应用 2017年第1期35卷 28-31页

作者：张涛丁伟许鹏郑云锋左少卿高雄厚兰州交通大学化学与生物工程学院甘肃兰州730070 中国石油兰州化工研究中心甘肃兰州730060 中国石油石油化工研究院北京100083

以酸性硅溶胶、碱性硅溶胶为原材料,考察了6种不同酸碱性质的硅溶胶与铝溶胶按硅铝比(质量比)1∶1混合后的凝胶情况和稳定性,并分别以铝溶胶、酸性硅溶胶与铝溶胶、碱性硅溶胶与铝溶胶为黏结剂制备催化裂化(FCC)催化剂,对其孔结构、酸... 详细信息

以酸性硅溶胶、碱性硅溶胶为原材料,考察了6种不同酸碱性质的硅溶胶与铝溶胶按硅铝比(质量比)1∶1混合后的凝胶情况和稳定性,并分别以铝溶胶、酸性硅溶胶与铝溶胶、碱性硅溶胶与铝溶胶为黏结剂制备催化裂化(FCC)催化剂,对其孔结构、酸性及酸量进行分析,考察了引入部分硅溶胶的FCC催化剂在性能上的变化。结果表明:硅溶胶与铝溶胶混合凝胶程度及稳定性受硅铝溶胶的浓度及p H值等因素的影响。酸性硅溶胶与铝溶胶不能直接混合,但可以用蒸馏水先稀释再混合,则不发生凝胶;碱性硅溶胶不能与铝溶胶直接混合,可调节碱性硅溶胶p H值为1~7;硅、铝混合溶胶催化剂与铝溶胶催化剂比较,孔体积和B酸、L酸的酸量减小,比表面积增加。

关键词：硅溶胶铝溶胶黏结剂催化裂化催化剂

Heavy tail and light tail of Cox-Ingersoll-Ross processes with regime-switching

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Science China Mathematics 2020年第6期63卷 1169-1180页

作者： Tongtong hou Jinghai shao School of Mathematical Sciences Beijing Normal UniversityBeijing 100875China Center for Applied Mathematics Tianjin UniversityTianjin 300072Chind

This study aims to investigate the tail behavior of Cox-Ingersoll-Ross(CIR) processes with regime switching. An essential difference shown in this study between CIR processes with and without regime switching is that the stationary distribution of those with regime switching may be heavy-tailed. We first provide sharp criteria to justify the existence of a stationary distribution for the CIR process with regime switching, which is applied to study the long-term returns of interest rates. Then, we provide a criterion to identify whether this distribution is heavy-tailed. Our results provide theoretical evidence of the existence of regime switching for interest-rate models based on empirical evidence of a heavy-tailed distribution.

关键词： regime switching heavy tail light tail ergodicity

Advances in Investigation of Fe-based Glass-forming Alloy Melts

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Journal of Iron and Steel Research International 2016年第6期23卷 509-515页

作者： Hui GAO Bang-shao DONG shao-xiong Zhou Advanced Technology & Materials Co. Ltd.Beijing Key Laboratory of Energy NanomaterialsCentral Iron & Steel Research Institute

Continuous precision casting is an important trend in modern *** effects in glassforming metallic liquids tremendously influence the properties of rapidly quenched ribbons;therefore,much attention has been paid to the study of Fe-based glass-forming melts at high *** investigations of these melts are categorized and *** is concluded that more efforts are still required to reveal the discipline of amorphization brought about by rapid quenching of Fe-based glass-forming melts.

关键词： metallic amorphous heating subsequent quenching viscosity discipline melting glasses crystalline

A Branching Random Walk Method for Many-Body Wigner Quantum Dynamics

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Numerical Mathematics(Theory,Methods and Applications) 2019年第1期12卷 21-71页

作者： Sihong shao Yunfeng xiong LMAM and School of Mathematical Sciences Peking UniversityBeijing 100871China

A branching random walk algorithm for many-body Wigner equations and its numerical applications for quantum dynamics in phase space are proposed and ana-lyzed in this *** an auxiliary function,the truncated Wigner equation and its adjoint form are cast into integral formulations,which can be then reformulated into renewal-type equations with probabilistic *** prove that the first mo-ment of a branching random walk is the solution for the adjoint *** the help of the additional degree of freedom offered by the auxiliary function,we are able to produce a weighted-particle implementation of the branching random *** contrast to existing signed-particle implementations,this weighted-particle one shows a key ca-pacity of variance reduction by increasing the constant auxiliary function and has no time discretization *** canonical numerical experiments on the 2D Gaussian barrier scattering and a 4D Helium-like system validate our theoretical findings,and demonstrate the accuracy,the efficiency,and thus the computability of the proposed weighted-particle Wigner branching random walk algorithm.

关键词： Wigner equation branching random walk quantum dynamics variance reduction signed-particle Monte Carlo method adjoint equation renewal-type equations importance sam-pling resampling

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使用光谱分析实现弯管中两相流含气率的预测

光谱学与光谱分析 2025年第1期45卷 231-238页

作者：车少敏马世一刘雪婧殷雄周延熊兵李锟李飞西安交通大学能源与动力工程学院陕西西安710049 中国航发四川燃气涡轮研究院四川成都610500 西安石油大学电子工程学院陕西西安710065

空气被夹带进入发动机润滑油系统形成油气两相流后,会严重影响润滑系统的正常运行。因此实现发动机润滑油系统中油气两相流含气率的准确和快速测量具有十分重要的意义。基于光谱匹配方法,对发动机润滑油系统在弯管处的油气两相流含气率... 详细信息

空气被夹带进入发动机润滑油系统形成油气两相流后,会严重影响润滑系统的正常运行。因此实现发动机润滑油系统中油气两相流含气率的准确和快速测量具有十分重要的意义。基于光谱匹配方法,对发动机润滑油系统在弯管处的油气两相流含气率进行了测量研究。首先使用近红外、可见光和紫外光谱仪获取油气两相流在2个流速、5个温度工况下0.10%~1.00%含气率范围(间隔0.06%)的吸光度数据并进行分析,确认油气两相流在三个波段下均有吸收,且吸收强度与含气率有关;其次提出将数据预处理结合光谱相似性测度方法并应用于弯管含气率光谱分析中,显著降低了基于原始光谱的含气率预测的最大相对误差。在近红外波段通过使用数据增强方法如中心化(center)和标准化(autoscaling)并结合光谱角余弦方法,得出新润滑油的含气率最大相对误差相对于原始光谱得到的数值从48%降低到36%。利用该方法分别在三个波段进行含气率预测,试验工况包括2个流速、5个温度,分析了两相流的温度和流速对含气率预测的影响。温度30.0℃,流速5.1 m·min^(-1)下,含气率信息在紫外波段(193.5~413.8 nm)与光谱向量的方向或形状差异的联系更为紧密,含气率预测的最大相对误差仅为6%。在近红外和可见光波段,流速或温度一定时,最大相对误差随着温度或流速的增加均有减小趋势。紫外波段下温度对含气率预测效果没有特定的影响规律,随着两相流的流速增加,含气率预测的最大相对误差有增大趋势。结果表明对于透光性较好的新润滑油,使用紫外光谱仪进行含气率数据的采集,含气率的预测选用标准化预处理结合光谱角余弦方法,得到的含气率预测最大相对误差最小。

关键词：气液两相流含气率光谱分析光谱匹配

ARTIFICIAL BOUNDARY METHOD FOR THE THREE-DIMENSIONAL EXTERIOR PROBLEM OF ELASTICITY

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Journal of Computational Mathematics 2005年第6期23卷 603-618页

作者： hou-de Han Chun-xiong Zheng Department of Mathematical Sciences Tsinghua University Beijing 100084 China Department of Mathematics University of Science and Technology of China Hefei 230026 China

The exact boundary condition on a spherical artificial boundary is derived for the three-dimensional exterior problem of linear elasticity in this paper. After this boundary condition is imposed on the artificial boundary, a reduced problem only defined in a bounded domain is obtained. A series of approximate problems with increasing accuracy can be derived if one truncates the series term in the variational formulation, which is equivalent to the reduced problem. An error estimate is presented to show how the error depends on the finite element discretization and the accuracy of the approximate problem. In the end, a numerical example is given to demonstrate the performance of the proposed method.

关键词： artificial boundary method unbounded domains elasticity

Unconventional 2D Periodic Nanopatterns Based on Block Molecules

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Chinese Journal of Polymer Science 2023年第10期41卷 1508-1524页

作者： Bo hou Wen-Bin Zhang Yu shao Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry&Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

This review summarizes the self-assembly of block molecules forming unconventional two-dimensional(2D)periodic ***,we emphasize the structural evolution from simple columnar phases to complex 2D tiling morphologies in soft materials including block copolymers,liquid crystals,giant molecules,***,the state-of-the-art nanofabrication technologies for making sophisticated nanostructures with specific functions via combining both bottom-up assembly and top-down lithography-based methods are discussed,highlighting the use of directed self-assembly ***,we provide our perspective on this *** further increasing the complexity of block molecules and the designability of lithography,low-dimensional ordered morphologies will be particularly promising for further application in nanotechnology.

关键词： Two-dimensional ordered morphologies Block molecules Directed self-assembly Nanofabrication Tilings and patterns

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硅溶胶制备催化裂化催化剂的凝胶及性能研究

石化技术与应用 2017年第2期35卷 112-115,118页

作者：张涛黄校亮丁伟郑云锋许鹏左少卿高雄厚兰州交通大学化学与生物工程学院甘肃兰州730070 中国石油兰州化工研究中心甘肃兰州730060 中国石油石油化工研究院北京100083

分别以酸、碱性硅溶胶为黏结剂制备催化裂化(FCC)催化剂,考察了催化剂制备过程中发生的凝胶现象及其原因,并将未发生凝胶的硅基黏结剂催化剂与铝基黏结剂催化剂进行了性能对比分析。结果表明:无论如何改变分子筛、硅溶胶、拟薄水铝石、... 详细信息

分别以酸、碱性硅溶胶为黏结剂制备催化裂化(FCC)催化剂,考察了催化剂制备过程中发生的凝胶现象及其原因,并将未发生凝胶的硅基黏结剂催化剂与铝基黏结剂催化剂进行了性能对比分析。结果表明:无论如何改变分子筛、硅溶胶、拟薄水铝石、盐酸等的加料顺序,均会发生凝胶;但不加入盐酸或拟薄水铝石,则不会发生凝胶;铝离子的存在是导致碱性硅溶胶发生凝胶的原因,但不引发酸性硅溶胶发生凝胶;电解质浓度过大是导致酸、碱性硅溶胶发生凝胶的共同原因;硅基黏结剂催化剂较铝基黏结剂催化剂的比表面积和B酸、L酸的总酸量均更大。

关键词：催化裂化(FCC) FCC催化剂黏结剂硅溶胶凝胶比表面积酸量

Quasi-Newton method based control design for unknown nonlinear systems with input constraints

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Science China(Information Sciences) 2020年第5期63卷 224-226页

作者： Shuangshuang xiong Zhongsheng hou Chenkun YIN Advanced Control Systems Lab School of Electronic and Information EngineeringBeijing Jiaotong University School of Automation Qingdao University

Dear editor,With the development in digital computers, various and huge data of controlled plants are obtained and stored, which has led to a rapid growth in the application of numerical methods in controller design. In recent years, the quasi-Newton method [1, 2], as one of the powerful numerical methods which has superlinear convergence speed

关键词： Newton Quasi-Newton method based control design for unknown nonlinear systems with input constraints