Benchmark-problem investigation for seismic response of a large-span cable-stayed bridge based on nonlinear stochastic optimal control

大跨度斜拉桥Benchmark问题的振动控制研究是当前国际结构控制研讨会的重要议题之一。以美国Bill Emerson Memorial斜拉桥第二阶段Benchmark模型为研究对象,在非线性随机动力学与控制的拟哈密顿理论体系框架下,运用基于随机平均法和随机动态规划原理的非线性随机最优(NSO)控制策略,对地震作用下的Benchmark模型进行MATLAB仿真分析。将最优控制力和性能评价指标与线性二次型Gauss(LQG)控制的计算结果进行对比,得出非线性随机最优控制策略能够更加有效地抑制斜拉桥的地震响应,提高结构的动力稳定性和抗震能力,具有更好的控制效果,对实际桥梁工程的振动控制具有较强的指导意义和适用价值。Investigation of vibration control for benchmark problems on large-span,cable-stayed bridge is one of the most important research topics in the current International Symposium on Structural Control. This paper studied secondstage benchmark problems on the Bill Emerson Memorial cable-stayed bridge. In terms of Hamiltonian theory for nonlinear stochastic dynamics and control, the benchmark model under seismic excitations was investigated using MATLAB simulation analysis,based on the stochastic averaging method and stochastic dynamic-programming principle. Comparison of analysis results for optimal forces and performance-evaluation indices between the nonlinear stochastic optimal( NSO)control strategy and the linear quadratic Gaussian( LQG) control strategy revealed that the former control strategy mitigates the seismic response of the cable-stayed bridge more effectively than the latter,thereby enhancing structural dynamic stability and earthquake resistance. In conclusion,the NSO control strategy demonstrates better control effect and presents instructive references and practical significance for vibration control of bridge-engineering applications.福建省青年人才项目(2008F3100

厦门地区非饱和残积土抗剪强度的试验研究

非饱和残积土是厦门地区诸多填方工程的工程用土,而岩土工程的强度与稳定性问题都涉及到非饱和土的抗剪强度及其指标.采用滤纸法测定非饱和残积土的基质吸力,通过一系列的直接剪切试验,测定不同初始含水量状态下土的抗剪强度及其强度指标.试验结果表明:基质吸力随着含水量、体积含水量或饱和度的增加而减小.当含水量小于16%,体积含水量大于35%或者饱和度大于70%时,基质吸力对含水量的变化非常敏感.在低基质吸力区,抗剪强度随着基质吸力的增加显著增加,表观粘聚力随基质吸力的增大而线性增加;在高基质吸力区,强度随基质吸力的增加变化不大,表观粘聚力的增长速率减小.表观内摩擦角仅在基质吸力较小时增加而后可近似为某一定值

甲烷无氧脱氢芳构化双促进W/MCM-22基催化剂研究

以MCM 2 2分子筛为载体 ,H2 SO4酸化的 (NH4) 2 WO4为W组分前驱物 ,以Zn和 /或Ga ,Co ,Mo为促进剂 ,研制两系列促进型W /MCM 2 2基催化剂 .在常压固定床连续流动反应器 GC测试系统评价其对CH4无氧脱氢芳构化的催化性能 ,结果显示 ,在双促进的W Co Mo(或W Ga Zn) /MCM 2 2催化剂上 ,常压、10 73K、原料气空速GHSV =15 0 0mL(STP)·h-1·(g cat.) -1的反应条件下 ,苯选择性最高达到 70 %～ 72 % ,相应甲烷转化率为～ 15 % ;反应 45 0min后 ,甲烷转化率降低到～ 5 %水平 ;7 5h平均积炭选择性～ 2 0 % .H2 TPR和NH3 TPD表征研究显示 ,在W /MCM 2 2基质催化剂中适当添加少量Co3 + / 2 + /Mon+ 或Ga3 + /Zn2 + ,一方面导致Wn+ 物种还原活化温度下降及可还原W6+ 物种数量增加 ,另一方面消去最强的一些B酸位同时诱生相当数量的中强酸位 ,这两方面的促进效应都对催化剂活性、选择性提高及结炭减缓作出贡献

Promotional Effects of Ni and Mg on the Preferential Oxidation of CO over Carbon Nanotube-Supported Pt Catalyst

采用共浸渍法制备了nI和Mg促进的碳纳米管载PT催化剂(PT-nI-Mg/CnT),考察了其对CO优先氧化的催化性能.结果表明,PT,nI和Mg在CnT表面发生了相互作用,可能存在合金纳米粒子,从而显著改善了催化剂CO优先氧化的催化性能.添加适量nI可提高CO的转化率,而加入适量Mg则有助于改善CO2的选择性.当PT,nI和Mg同时负载时,优化后所得的催化剂5%PT-5%nI-5%Mg/CnT在100°C对富H2气体中CO选择氧化的转化率为100%,CO2的选择性为53.7%;该催化剂在140°C下连续反应24H,催化活性稳定.A carbon nanotube-supported Pt catalyst promoted by Ni and Mg(Pt-Ni-Mg/CNT) was prepared by the co-impregnation method for preferential oxidation of CO in H2-rich gas.The results of X-ray diffraction, H2 temperature-programmed reduction, transmission electron microscopy, and energy dispersive spectroscopy indicated that Pt interacted with Ni and Mg on CNT surface and might form alloy nanoparticles to some extents, which in turn markedly improved the catalytic performance of preferential oxidation of CO in H2-rich gas.The results of performance tests showed that CO conversion at low temperatures could be effectively enhanced by adding a proper amount of Ni, while the selectivity was improved by adding a proper amount of Mg.When Ni and Mg were added simultaneously, the 5%Pt-5%Ni-5%Mg/CNT catalyst showed CO conversion of 100% and selectivity for CO2 of 53.7% in a H2-rich stream at 100 °C.The catalytic performance did not change obviously during 24 h of run at 140 °C.国家重点基础研究发展计划(973计划;2009CB939804);福建省科技重大专项前期项目(2009HZ10102

Vapor-phase hydrogenation of dimethyl oxalate over a CNTs-Cu-SiO2 hybrid catalyst with enhanced activity and stability

National Basic Research Program of China [2011CBA00508]; Natural Science Foundation of China [21173175, 20923004]; Research Fund for the Doctoral Program of Higher Education [20110121130002]; Program for Changjiang Scholars and Innovative Research Team in University [IRT1036]; Singapore Agency for Science, Technology and Research (SERC) [102 101 0020]Hybrids containing carbon nanotubes (CNTs) have attracted considerable attention in heterogeneous catalysis. In this study, a CNTs-Cu-SiO2 hybrid fabricated by urea-assisted gelation is disclosed to display excellent activity and outstanding long-term stability in the vapor-phase hydrogenation of dimethyl oxalate (DMO). Appropriate hybridization of CNTs with Cu-SiO2 results in enhanced Cu dispersion, which is suggested to be one of the key factors in determining the catalytic performance of copper catalysts. Furthermore, the growth of Cu nanoparticles (NPs) during the catalyst activation, DMO hydrogenation and severe aging tests is distinctively inhibited by incorporating CNTs into Cu-SiO2, leading to remarkably enhanced catalytic stability. The adsorption and activation of hydrogen on this particular hybrid catalyst are also influenced by the CNTs introduction

PVP-stabilized heteropolyacids as reusable self-assembling catalysts for alcoholysis of cellulosic saccharides

National Basic Research Program of China [2011CBA00508]; Natural Science Foundation of China [20923004, 21173175]; Research Fund for the Doctoral Program of Higher Education [20110121130002]; Program for Changjiang Scholars and Innovative Research Team in University [IRT1036]Polyvinylpyrrolidone-stabilized heteropolyacids (PVP-HPAs) are synthesized by self-assembling in alcohol. The structure of PVP-HPAs is determined by various characteristic techniques. HPAs can protonate PVP to form polymeric cations. In turn, the protonated PVP interacts strongly with the heteropolyanion by forming an ionic liquid (IL)-like structure. The self-assembling separation and recyclability characteristics are related to the PVP's IL-like structure. The catalyzing performance of PVP-HPAs varies with the species of HPA and the content of PVP. The optimized PVP-H4SiW12O40 center dot 5H(2)O (HSiW) (1/5 : 3/4) gives more than 60% conversion of cellulose and complete conversion of highly selective cellobiose into butylglucosides. The optimized PVP-HSiW is separated directly by centrifugation and retains the activity without any post-treatment during recycling. The deactivation of PVP-HPAs is related to the loss of the catalyst during recycling. The functional mechanism of the IL-like structure is explored in this control experiment

Promotional Effects of Ni and Mg on the Preferential Oxidation of CO over Carbon Nanotube-Supported Pt Catalyst

A carbon nanotube-supported Pt catalyst promoted by Ni and Mg (Pt-Ni-Mg/CNT) was prepared by the co-impregnation method for preferential oxidation of CO in H-2-rich gas. The results of X-ray diffraction, H-2 temperature-programmed reduction, transmission electron microscopy, and energy dispersive spectroscopy indicated that Pt interacted with Ni and Mg on CNT surface and might form alloy nanoparticles to some extents, which in turn markedly improved the catalytic performance of preferential oxidation of CO in H-2-rich gas. The results of performance tests showed that CO conversion at low temperatures could be effectively enhanced by adding a proper amount of Ni, while the selectivity was improved by adding a proper amount of Mg. When Ni and Mg were added simultaneously, the 5%Pt-5%Ni-5%Mg/CNT catalyst showed CO conversion of 100% and selectivity for CO2 of 53.7% in a H-2-rich stream at 100 degrees C. The catalytic performance did not change obviously during 24 h of ran at 140 degrees C

SURVEY OF MIXED INFECTIONS OF FISH-BORNE TREMATODES IN PINYUAN COUNTY AND DNA(RAPD)ANALYSIS

目的　调查广东省平远县棘隙吸虫及其他鱼源性吸虫混合感染情况。方法　对鱼类宿主取鱼鳃和鱼肉等组织 ,镜检囊蚴 ;用水洗过筛沉淀法粪检虫卵 ,部分虫卵阳性动物解剖检查。采用DNA -RAPD技术 ,比较福建棘隙吸虫广东株与福建株。结果　查出华支睾吸虫 (Clonorchissinensis)、东方次睾吸虫 (Metorchisorientalis)、福建棘隙吸虫 (Echinochasmusfujianensis)、日本棘隙吸虫 (E japonicus)、抱茎棘隙吸虫 (E perfoliatus)和钩棘单睾吸虫 (Haplorchispumilio) 6种。第二中间宿主为麦穗鱼等 11种 ,感染率 48 3% (182 / 377) ,有 92 4%的阳性鱼混合感染 2种以上吸虫囊蚴。保虫宿主狗、猫感染率 79 2 % (19/ 2 4) ,每只阳性动物均有 2种以上吸虫混合感染。 15个引物在福建棘隙吸虫广东株与福建株两者共获DNA片段 185个 ,共享度 (F) =0 984,遗传距离 (D) =0 0 16。结论　当地为人兽共患的多种鱼源性吸虫混合感染区。形态学观察和分子生物学检测结果相印证 ,福建棘隙吸虫广东株与福建棘隙吸虫福建株为同一虫种。Aim To seek the possible existence of mixed infections of Echinochasmus fujianensis and other fish-borne tremtodes in Pinyuan county,Guangdong.Methods Metacercariae of trematodes were detected from gills,muscles and some other tissues of freshwater fish and examintd under microscopy Sedimentation pocedures were used to observe parasite ova in stool Adult worms were obtained from definitive animal hosts upon dissection Experimental animal infection were performed from metacercariae of E fujianensis strains in Fujian and Guangdong,and it's DNA analysis Random amplified Polymorphic DNA(RAPD).Results Six species of trematodes were found,including Clonorchis sinensis,Metorchis orientalis,E fujanensis, E japonicus,E perfoliatus and Haplorchis pumilio Eleven species of freshwater fish comprising Pseudorasbora parve were identified as the second intermediate hosts,with an average positive rate of 48 33%(182/377) The overall mixed infection animal were contracted with 2 or more species Dogs and cats were detected to be reservoir hosts,the total infection rate being 79 2%(19/24).92 4% of infecded fish were contracted with 2 or 6 speies of the metacercariae of trematodes 185 DNA fragments were obtained by 15 primers,F=0 894 and D=0 016 between E fujianensis Guandong and Fujian strain Conclusion There are six species of fish-borne trematodes which may cause infections in human and animal in the regions E fujianensis Guangdong stain and Fujian strain are the same species福建省科技计划基金!资助项目 (No 98-Z - 1 56);; 福建省“百千万人才”人选培养资

Study on Phenolic Foam

［中文文摘］针对影响酚醛泡沫性质的众多参数的不确定性 ,给出了可发泡性甲阶酚醛树脂的合成方法及酚醛泡沫塑料发泡典型配方 ;考察了反应温度及水含量对酚醛树脂粘度的影响 ,讨论了表面活性剂、发泡剂、固化剂及发泡温度对泡沫性能的影响。结果表明 :当表面活性剂用量为 4%～ 7% ,发泡剂用量为 4%～ 10 % ,固化剂用量为 8%～ 12 % ,发泡温度在 70～ 80℃范围时 ,可制得较好的酚醛泡沫塑料。［英文文摘］This study presented the experimental results on the preparation and characteristics of resol and phenolic foam because of a very wide range of process variables with little indication of preferred or desired process parameters. The effects of reaction time and water concentration on the resin viscosity were studied. The effects of surfactant, blowing agent, acid catalyst and foaming temperature on the density of phenolic foam were also investigated. When the surfactant content was 4%～7%, blowing agent content 4 %～10 % , acid catalyst content 8 %～12 % , and at foaming temperature 70 ℃ ～ 80 ℃, phenolic foams with good properties could be prepared.固体表面物理化学国家重点实验室基金 (1130

Study on Improvement of Tensile Strength of Polyimide Film

［中文文摘］以二步法制备了均苯型聚酰亚胺薄膜,研究了提高聚酰亚胺薄膜力学性能的方法.结果表明,添加了磷酸三苯酯后,聚酰亚胺薄膜的拉伸强度得到显著提高;当磷酸三苯酯的添加量为聚酰亚胺质量的 3%时,聚酰亚胺薄膜的拉伸强度可提高1.8倍;经红外光谱测试,添加磷酸三苯酯后不会改变原来聚酰亚胺分子的结构.不同的去溶剂温度和热亚胺化的升温方式对聚酰亚胺薄膜拉伸强度也有较大的影响.去溶剂温度为 90℃,以 8℃/min的升温速率进行热亚胺化,热亚胺化的最高温度设定为375℃,采用分两段的阶梯式升温方式,均有利于提高聚酰亚胺薄膜的拉伸强度.［英文文摘］A study of mechanical properties is of importance for investigation of phase aggregation states,structure,and interactions in polymer chains which determine the suitability of a polyimide film in a specific application.In this paper,the methods to improve the mechanical properties of polyimide film based on pyromellitic dianhydride (PMDA) and 4,4’-oxydianiline (ODA) have been researched.When triphenyl phoshpate is added,the tensile strength of polyimide film is obviously improved.When the addition is the weight of polyimide film’s 3 % , the tensile strength is increased 1. 8 fold compared to the original. By inf rared analysis , the st ructure of polyimide film added triphenyl phoshpate has not been changed ,and it stensile strength is approaching to Kapton H film’s. The tensile st rength of polyimide film will also be affected by the temperature of desolvent and the heating way of thermal imidization. When the process of desolvent is kept at 90 ℃,or the heating rate of thermal imidization is 8 ℃/ min ,or the top temperature of thermal imidization is 375 ℃,or the heating way of two steps is used ,the tensile st rength of polyimide film can be improved too. In a word ,we have found that many factors have influenced on the tensile strength of polyimide film. After our work ,the tensile strength have been greatly improved