Aerodynamic admittance of along-wind loads on tall buildings

高层建筑顺风向的脉动风荷载通常是基于准定常假设,由来流风速的功率谱密度函数和相干函数求得,其中风荷载和风速功率谱密度对气动导纳函数影响较大。依据; 10个典型高层建筑模型的同步测压风洞试验数据,对高层建筑各层高度处顺风向荷载的功率谱密度函数和气动导纳函数的特性进行分析,提出了顺风向荷载气动导; 纳函数的表达式,并针对公式中的具体参数进行了拟合。采用该表达式对一栋实际高层建筑的顺风向风致动态响应进行计算,并与其模型的试验结果进行对比。结果; 表明:高层建筑顺风向荷载的气动导纳曲线沿高度变化不大,但与其截面形状关系较大,曲线整体呈指数分布,当折减频率小于0.1时,气动导纳数值均接近于1; .0。算例结果表明,采用所建议的气动导纳拟合式计算出的风致响应结果与风洞试验计算结果较为吻合,误差在10%以内。Along-wind fluctuating loads on tall buildings are usually obtained by; power spectra and coherence functions of inflow wind velocity based on; the quasi steady theory. In this process, the aerodynamic admittance of; along-wind loads plays an important role. Ten tall building models with; different section shapes were tested using simultaneous pressure; measuring technique in a wind tunnel. According to the test data, the; power spectra and aerodynamic admittances of along-wind loads on every; layer in the terrain category B and D were analyzed in detail and the; fitting formula of the aerodynamic admittances was proposed. Parameters; in this formula were given accordingly. The wind-induced responses of an; actual high-rise building were calculated by the formula given here and; random vibration method based on wind tunnel test data respectively. The; results show that the aerodynamic admittances of along-wind loads on; different height of the same tall building have little discrepancy and; vary with the section shapes. All of the aerodynamic admittances satisfy; the exponential law and approach 1.0 when the reduced frequency is less; than 0.1. The response using present aerodynamic admittance agrees well; with one from the wind tunnel experiment and the error is less than 10%.国家自然科学基金重大研究计划重点项

The Analysis of the Application of Asset Securitization in Chinese Enterprises

从全球资本市场的发展历程以及金融实践来看，资产证券化是资本市场发展和演化到一定程度的必然产物，有助于推进股票市场、债券市场、信贷市场以及货币市场的共同发展，有利于提高金融服务的整体水平。2013年以来，党中央、国务院将资产证券化提升到了一个非常重要的高度，该领域近期也成为了中国金融市场理论学术界和实务操作界共同关注的热门领域。 本文重点研究资产证券化在我国企业中的实际应用问题，对资产证券化在我国实务操作中的三种主要的业务模式——银监会监管下的信贷资产证券化、证监会监管下的企业资产证券化、银行间市场交易商协会管理下的资产支持票据的交易主体、交易结构以及交易流程的一般范式进行分别的研究，并通过对...Through the development process and the financial practice of the global capital market, we can see that asset securitization is the inevitable outcome of the development and the evolution of the capital market. Asset securitizaion can contribute to the collaborative development of the market of stock, bond, credit and money. It can contribute to improving the service of finance. Since 2013, the P...学位：工商管理硕士院系专业：管理学院高级经理教育中心（EMBA项目）_高级管理人员工商管理硕士(EMBA)学号：X200815606

高层建筑抗风网络数据库平台的构建

风荷载是高层建筑结构设计的控制性荷载之一,其取值大小直接影响到高层建筑结构的安全性与舒适性。本文构建了一个基于互联网应用程序的高层建筑抗风数据库平台,详细描述了该网络数据库平台的基本框架、软件设计及工程应用。应用结果表明,该平台能将大量风洞试验数据进行整理、存储、在线计算,得到结构设计所需的风荷载,并通过Internet向公众开放,可大大减少传统规范中运用表格、图表以及拟合公式所带来的误差,可作为结构抗风设计的有效手段

Preparation of Nearly Stoichiometric SiC Fibers Derived From PCS by the control of atmosphere

本文通过控制裂解气氛制备了近化学计量比SiC纤维。采用先氢气后氩气的分阶段气氛控制和全过程不同体积比氢气及氩气的混合气氛路线，研究了这两种路线中不同的工艺对SiC纤维的C/Si原子比及纤维性能的影响规律，并探索了氢气对PCS裂解的作用机理。研究结果表明：①分阶段气氛工艺路线中，气氛转换温度Th从600℃升高至1200℃，得到的SiC纤维的C/Si原子比从1.54降低至0.79，当Th=800℃时，可得到近化学计量比SiC纤维。在纯氢气氛下裂解获得SiC纤维截面上的C/Si原子比呈现芯部高、边缘低的变化趋势；②在氢气和氩气的混合气氛条件下，随着氢气浓度逐渐升高，SiC纤维C/Si原子比从1.81...Nearly stoichiometric SiC fibers derived from PCS by the control of atmosphere were investigated in this thesis，namely first in H2 atmosphere then in Ar atmosphere and H2/Ar mixed atmosphere. Atomic ratio and properties of fabricated SiC fibers were studied，and the effect of H2 in the pyrolysis of PCS was explored. The results show as follow: ①When atmosphere changing temperature Th changes fr...学位：工学硕士院系专业：化学化工学院_材料物理与化学学号：20033601

桩基动力参数的灵敏度分析

将桩基简化成离散的多自由度系统,对其纵向振动的动力参数进行了分析,对桩基的振动参数频率、振型、频响函数与频域响应对刚度改变的灵敏度进行了数学推导.可知频率对刚度改变的灵敏度很小,振型对刚度改变的灵敏度也不大,但在节点处有一定的影响,频响函数与频域响应对刚度的变化反应比较明显,并且用一个实例进行了验算,得到的结果与理论推导吻合良好

论财政支出改革

财政支出改革应从建立国库单一账户体系入手 ,加大收支两条线改革的力度 ,首先应把市直预算单位的资金运动纳入国库单一账户体系 ;应实行会计委派制 ,建立会计工作站 ,把市直预算单位的财务活动纳入会计集中核算 ;应全面落实政府采购制度 ,试行国库直接支付 ,统一开支标准 ,实行综合预算

中烈度高风压地区基础隔震高层建筑响应分析

针对高层建筑在中烈度地震时减震系数值较大以及在高风压下可能引起其隔震支座受拉等原因导致中烈度高风压地区基础隔震高层建筑的研究较少的问题,以一栋处于初步设计阶段的基础隔震高层建筑为研究对象,详细分析了该高层建筑在达到不同设防水准的地震和不同重现期风荷载的作用下,上部结构以及隔震支座的各种响应和减震效果.结果表明,在中烈度高风压地区,可以设计安全可靠的基础隔震高层建筑,且达到良好的减震效果

Degradation of 2-methylisoborneol in water by hydroxyl radical

二-甲基异莰醇(2-MIB)是一种由蓝绿藻以及放线菌等微生物产生,具有桥环结构的饱和叔醇,在水中具有令人厌恶的土霉味,常规水处理工艺难以对其氧化; 降解.利用大气压强电离放电生成羟基自由基(·OH),对2-MIB进行氧化降解,确定了其氧化剂剂量效应、时间效应关系,并利用GC-MS对2-MIB; 氧化降解过程中间产物的分析,推断其氧化降解机制.结果表明:对初始浓度为150,300ng/L的2-MIB,分别投加总氧化剂TRO1.8,2.3m; g/L,接触反应6s去除率分别为96%和97.6%,处理后残余浓度低于10ng/L; (低于人类嗅阈值).在2-MIB水样中加入·OH淬灭剂叔丁醇(TBA)后,2-MIB的去除效果明显降低,证明氧化降解2-MIB的主要为·OH.另; 外通过对氧化降解过程中间产物分析表明,·OH能破坏2-MIB的桥环结构,并最终矿化生成CO_2和H_2O.2-methylisoborneol (2-MIB) produced by cyanobacteria and actinomycetes; is a saturated bicyclic-tertiary alcohol, which can cause earthy/musty; taste and odor in surface water. Moreover, 2-MIB is usually difficult to; be decomposed and removed by conventional water treatment process. In; this paper, hydroxyl radical (·OH) generated by a strong ionization; discharge process at atmosphere pressure was used to degrade 2-MIB in; water, of which the removal efficiency including dose effects and; contact reaction time were investigated. The intermediate products; formed in ·OH treatment process were analyzed by GC-MS, and the; oxidative degradation mechanism of 2-MIB by ·OH was discussed. Results; show that the removal rate for 2-MIB with initial concentration of 150; and 300ng/L could reach 96% and 97.6% within 6.0s, while the total; reactive oxidant (TRO) dose were 1.8 and 2.3mg/L, respectively. After; ·OH treatment, the concentration of 2-MIB in water was lower than 10ng/L; (lower than the human olfactory threshold). The degradation effects of; 2-MIB were obviously reduced by the ·OH scavengers tertiary butyl; alcohol (TBA), indicating that ·OH should be the main oxidant for 2-MIB; oxidative degradation. By analyzing the intermediates produced in the; oxidative degradation process, it was found that the bridge ring; structures of 2-MIB could be destroyed by ·OH and finally mineralized to; CO_2 and H_2O.国家科技支撑计划项目; 国家重大科研仪器研制项目; 科技部创新人才推进计划重点领域创新团队; 辽宁省重点实验室基础研究项

Preliminary Study on Thermochemical Curing of Polycarbosilane Fibers

［中文文摘］以异丙醇锆(ZIP)为交联剂、聚碳硅烷(PCS)为先驱体,在Ar气氛的保护下通过干法纺丝、热化学交联工艺使PCS从热塑性转变热固性结构。研究了该工艺对PCS纤维质量变化、Si-H反应程度、溶解性及氧含量等性能的影响。实验结果表明:在不熔化过程中,PCS结构中的Si-H键与ZIP反应,在PCS分子间形成Si-O-Zr交联结构,随着交联温度和保温时间的升高,Si-H反应程度和纤维失重率相应提高;在测试范围内最大Si-H反应程度为73.06%,失重率2.678%,氧含量低于2.0%。［英文文摘］Polycarbosilane from dry spinning to SiC fiber through thermochemical curing,which is catalysed by zirconium iso-propoxide(ZIP) under Ar gas stream,is transformed from thermoplastic to thermoset structure.The effects of curing temperature and holding time on cured PCS fibers are mainly studied in this paper.The experimental result shows that Si-H bonds in polycarbosilane are crosslinked by ZIP during the curing process which is made up of Si-O-Zr structure in PCS molecule.And the reaction degree of Si-H bonds and mass loss of fibers are increased accordingly with thetemperature and holding time rising.The maxium reaction degree of Si -H bonds is 73.06%, mass loss 2.678%,and oxygen content no more than 2.0%, respectively.总装备部预研基金资助(51412020404QT870

A Parallel Algorithm for Fresnel Tomography

摘要:与射线层析成像相比, Fresnel 层析成像考虑波频率的影响, 具有较高的分辨率,但所需的存储 空间和计算量更大,因此提出了Fresnel 层析成像的并行算法1 把大型层析反演方程组的求解,转化成 对其中的各个方程进行相互独立的计算,避免了大型系数矩阵的存储问题;把一个Fresnel 带的正演和 反演计算放在一个进程,不同Fresnel 带的计算相互独立进行,不需要信息传递,达到了极高的并行度; 从进程之间没有通信, 仅当从进程计算结束后,在主进程与各从进程之间有少量的数据传递,使通信开 销达到了极小的程度1 应用MPI 在Linux PC 集群环境下实现了该算法,实际测试表明,该算法具有较 高的并行度和加速比.Abstract 　In cont rast with ray2based t raveltime tomography , Fresnel tomography account s for the band2 limited nature of seismic waves and gives the higher resolution tomograms1 Because Fresnel tomography demands much computer memory and much running time , a parallel algorithm for it is proposed1 The tomographic inversion is t ransformed to resolving respectively a series of single equation in light of backprojection principle , each equation corresponding to a Fresnel zone1 The forward and inverse computation concerning a Fresnel zone is allocated to one process and is independent of other processes1 Then the storage and calculation of the large2scale mat rix in the tomography are avoided1 No message delivers between the slave processes , and only a little of data delivers between a master process and the slave ones1 By using the portable message passing interface standard (MPI ) for the communication , the computing code of the algorithm is implemented on Linux system , which allows to dist ribute the work on several PCs connected via standard Ethernet in an in2house network , and greatly expands the applicability of Fresnel tomography1 The test s on the synthetic and observed seismic t ravel time data show that this parallel algorithm has a good performance on Linux PCs1基金项目:国家自然科学基金项目(40774065) ;福建省自然科学基金项目(2006J0044