内置钢箱-混凝土连续组合梁受力性能试验

为研究超静定内置钢箱-混凝土组合梁的塑性设计方法,进行了4根两跨内置钢箱-混凝土连续组合梁试验,获得了试验梁裂缝分布与开展、变形发展、破坏特征及塑性内力重分布等方面的试验结果.通过分析,给出了内置钢箱-混凝土连续组合梁等效塑性铰区长度计算公式,提出了以支座控制截面弯矩弹性计算值与组合梁正截面破坏时钢箱所承担弯矩之差为调幅对象、以相对塑性转角为自变量的弯矩调幅设计方法.     

脉冲加热方法铌热物性参数的动态测量

提出积分球反射法脉冲加热技术测量材料热物性的方法,研制的脉冲加热瞬态热物性测量装置能同时测量铌带状试样温度范围在1100-2700K的比热容、电阻率、全波长半球发射率.装置中高速高温计测量试样的辐射温度,积分球反射计测量试样的法向光谱发射率,即可得出带状试样的真实温度.再通过测得的试样上的电压、电流等数据经计算获得其他热物性参数.对国外的标准铌试样进行了测试,所得测量数据与国外同行数据进行了比对,具有较好的一致性.实验结果表明:比热容测量不确定度为5%,全波长半球发射率测量不确定度为3.5%,电阻率的测量不确定度为3.6%,测量数据可作为航天、军事和民用领域材料应用的设计依据.     

递推批量MGM(1,N)模型在滑行艇运动姿态预报中的应用

为了设计出有效的滑行艇的自动控制系统,需要建立预测模型对其运动姿态进行实时的、精确的预报.分析利用MGM(1,N)模型对滑行艇运动姿态进行预报的适用性.同时,针对滑行艇运动姿态数据的特点和预报的实时性要求,提出了新采集了一批数据之后,计算模型的参数矩阵的递推公式.利用该公式可以在提高预测精度、延长预测时间的同时,不会显著的增加计算量.数值仿真试验的结果表明,将批量递推MGM(1,N)模型应用于滑行运动姿态预报是可行的,并且具有非常高的预测精度.     

树枝状荧光探针设计制备及荧光特性初步研究

树枝状荧光探针是将荧光染料引入树枝状化合物（dendrimer）端基的一类化合物,具有良好的稳定性及光谱特性．笔者以2,2-二甲氧基乙胺为核,采用发散合成法合成了一端含活性氨基的扇形树枝状化合物,并将羧基噻唑橙染料（TO—COOH）引入树枝状化合物的端基,制备出树枝状荧光分子．初步研究了其荧光特性,讨论了反应温度、反应时间等条件对反应收率的影响．     

数据集市技术浅析

数据集市是当前数据仓库建设的重要环节,本文通过对目前某电信的数据现状进行分析,给出了两种数据集市的建设方案,并分别对两种方案特点进行了描述。解决了电信所遇到的数据问题。     

Synthesis and properties of poly(amide–imide)s based on N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide,p‐aminobenzoic acid and various aromatic diamines

A new diimide–diacid monomer, N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide (I), was prepared by azeotropic condensation of 4,4′‐oxydiphthalic anhydride (ODPA) and p‐aminobenzoic acid (p‐ABA) at a 1:2 molar ratio in a polar solvent mixed with toluene. A series of poly(amide–imide)s (PAI, III_a–m) was synthesized from the diimide–diacid I (or I′, diacid chloride of I) and various aromatic diamines by direct polycondensation (or low temperature polycondensation) using triphenyl phosphite and pyridine as condensing agents. It was found that only III_k–m having a meta‐structure at two terminals of the diamine could afford good quality, creasable films by solution‐casting; other PAIs III using diamine with para‐linkage at terminals were insoluble and crystalline; though III_g–i contained the soluble group of the diamine moieties, their solvent‐cast films were brittle. In order to improve their to solubility and film quality, copoly(amide–imide)s (Co‐PAIs) based on I and mixtures of p‐ABA and aromatic diamines were synthesized. When on equimolar of p‐ABA (m = 1) was mixed, most of Co‐PAIs IV had improved solubility and high inherent viscosities in the range 0.9–1.5 dl g^?1; however, their films were still brittle. With m = 3, series V was obtained, and all members exhibited high toughness. The solubility, film‐forming ability, crystallinity, and thermal properties of the resultant poly(amide–imide)s were investigated. © 2002 Society of Chemical Industry     

Well-defined polymer precursors synthesized by RAFT polymerization of N,N-dimethylacrylamide/N-acryloxysuccinimide: random and block copolymers

N,N-dimethylacrylamide (DMA) and N-acryloxysuccinimide (NAS) were copolymerized by the reversible addition–fragmentation chain transfer (RAFT) polymerization technique, to obtain random and block copolymer precursors onto which different side-groups may be statistically grafted via the reactive NAS units. These reactive copolymers have interesting applications in various fields such as coatings and paints, water purification and biology. Random poly(DMA-co-NAS) copolymer chains were synthesized with a 75/25 molar ratio, high conversion, an excellent molecular weight (MW) control from 5000 to 130 000 g mol⁻¹, and low polydispersity index (M_w/M_n<1.1). Poly(DMA-b-NAS) block copolymers were synthesized by a two step method, in which a poly(DMA) homopolymer was prepared first and then used as macro-chain transfer agent to polymerize NAS. For example, a poly(DMA-b-NAS) sample was obtained with an average molecular weight of 44 300/7400 g mol⁻¹ corresponding to 447 DMA and 44 NAS units. Such block copolymers had not yet been synthesized by any controlled polymerization technique. They can be used to prepare polymers with exactly the same backbone and an increasing number of different side groups (e.g. hydrophobic, ionic or fluorescent).     

Interphases in the Adhesive Bonding of Fluoropolymers

Strong and durable adhesive bonds may be made between polytetrafluoroethylene (PTFE) and either cyanoacrylate (CA) or epoxy adhesives, if the PTFE surface is modified by the use of a “primer” such as triphenylphosphine (TPP) or diaminodiphenylmethane (DDM). The primer mixes with the PTFE surface, and the modified surface is then capable of forming an interphase, tens to hundreds of nanometers thick, where interpenetration of the adhesive and adherend occurs. Using CA adhesives, PTFE/CA/PTFE block compression shear bond strength (ASTM D4501-85) of over 10 MPa can be achieved, with failure occurring cohesively. Initial work with epoxy adhesives indicates that the use of DDM primer gives adhesive bonds comparable in strength with those produced by modification of the fluoropolymer surface by sodium naphthalenide.     

Investigation of conductivity characteristics of nitrile butadiene rubber vulcanizates filled with semiconducting carbide ceramic

SiC‐ and B₄C‐filled NBR rubber composites were prepared with various volume fractions of filler by a conventional roll‐mill method. The morphological structures of the NBR–SiC and NBR–B₄C composites were analyzed by scanning electron microscopy. The dependence of room‐temperature volume resistivity (ρ_v) on the concentration of filler in the two systems was studied. In addition, variation in the number of current carriers (n), mobility carriers (μ), dielectric constant (ε), and dielectric loss factor (tan δ) on filler concentration in the two systems were investigated in detail. The applicability of composites as negative temperature coefficient (NTCR) linear thermistors was studied by the dependence of volume resistivity on temperature. The resistivity showed negative temperature dependence and changed linearly with temperature parallel. The conduction mechanism of the conductivity of the two composites was analyzed in terms of the computed activation energy and hopping energy. Change in volume resistivity as a function of frequency for the two systems was also investigated. Finally, the dependence of volume resistivity on applied pressure and possible real applications of these composites as transducers in pressure sensors were also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2158–2165, 2007     

虚拟校园漫游与实时可视化研究

将虚拟现实技术和人机工程相结合,基于Crystal Space 3D平台实现虚拟校园系统。该系统由数据和软件两部分组成,数据部分包括多媒体数据和三维模型数据。在建模阶段引入面向对象思想并大量使用纹理,降低了三维模型的复杂度。同时,使用XML描述导出后的模型,使模型数据更容易被读取和解析。软件部分支持多种输入硬件、支持不同的漫游方式和对虚拟校园中指定地点的查询及自动寻路,并配以介绍学校文化的背景音乐,使整个虚拟系统在突出虚拟现实交互性、沉浸性等独有特性的同时,最大限度考虑“人”的使用因素,提供多样的使用方法和舒适的使用环境等人机工程特性,使系统的实用性更强。