空气中^131I的取样和测量方法的研究

本文介绍一种气态和气载~(131)I 取样器。着重介绍了一种指数分布源的效率刻度方法,讨论了与取样有关的一些问题。     

Dynamics of novel hydrogen-bonded acidic fluorinated poly(amide-imide-silica) hybrids studied by solid-state NMR

Novel hydrogen-bonded acidic fluorinated poly(amide-imide-silica) hybrid materials, FPAI-SiO₂ (6E and 6F) series, were synthesized by a sol-gel process. The structures and spin relaxation of the hybrids were characterized by infrared (IR), and ²⁹Si and ¹³C nuclear magnetic resonance (NMR) spectroscopy. The abundant Q⁴ structures implied that in free catalyst the degree of condensation of tetramethoxysilane was enhanced by hydrogen-bonded acidic fluorinated poly(amide-imide). The dynamics on the local mobility of the hybrids was investigated by the time constant for energy exchange between ¹H and ²⁹Si spin system (T_SiH) and spin-diffusion path length (L) measurements. It was found that the faster T_SiH of 6E and 6F hybrids compared with the previous study of similar 6C and 6D hybrids implied that 6E and 6F hybrids had more aggregated structures even though the organic terminal segment changed from rigid imide to more flexible amide. The interactions of the charge transfer between donor and acceptor molecules or π-π aromatic stacking may be the dominant factors to affect the structures of 6E and 6F hybrids. Moreover, M¹ and D² segments of 6F hybrids had the same level mobility and the mobility of the 6F hybrids was little improved as the soft and flexible 1,3-bis(3-aminopropyl)-tetramethyl-disiloxane segment was incorporated in the dense structures of 6F hybrids. All of the L values of 6E and 6F hybrids were on the scale of 3.5-4.0 nm. The result also suggested that 6E and 6F hybrids had similar denser structures as 6D hybrids.     

Films and fibers of oriented single wall nanotubes

As-produced nanotubes form a light, fragile and isotropic soot. Different efforts are made to process nanotubes into macroscopic forms of more practical use and more controlled properties. We briefly review in this paper two methods recently proposed to make films of magnetically aligned nanotubes and fibers by using an electrophoretic method. Preferential orientation of the nanotubes in the plane of the films or along the fiber axis is an important feature of the obtained materials. Then we describe in details a different, spinning like, process for making fibers out of single wall carbon nanotubes. This process consists of dispersing the nanotubes in a surfactant solution, re-condensing the nanotubes in the flow of a polymer solution to form a nanotube mesh, and then collating this mesh to a nanotube fiber. The behaviors of the surfactant-stabilized dispersions, which are also presented, are critical for this process. The degree of nanotubes alignment in dried fibers has been characterized by X-ray scattering. It is found to be smaller than the alignment obtained in the previous materials. However, the processing is simpler and faster and potentially scalable for large-scale production.     

低密度MTC固井液在低渗透气井的试验研究

针对陕甘宁盆地低渗透气田天然气井地层漏失等问题，通过室内试验，设计了密度为１．４１～１．６０ｇ／ｃｍ３的二级固井高炉矿渣——ＭＴＣ水泥浆和ＡＰＩＧ级水泥——ＭＴＣ水泥浆。目的提高固井质量、降低固井成本。结果通过对高炉矿渣的水化机理和两种ＭＴＣ水泥浆对比分析，认为高炉矿渣——ＭＴＣ转化法较ＡＰＩＧ级水泥——ＭＴＣ转化法，具有外加剂用量少、抗压强度高、体系简单、固井成本低等特点。结论两种低密度ＭＴＣ水泥浆配方设计合理，性能优良，能满足现场施工的要求。     

Planning the GMAW process by constraint propagation

Although the gas metal arc welding (GMAW) process is widely used for joining metals, its planning is still a cumbersome task. The planning procedure involves many complex interrelationships among the process variables and depends heavily on empirical knowledge. Therefore, a solution method that allows a convenient way to represent the domain knowledge and evaluate the process variable relationships is needed. Further, the lack of a strong domain theory to quantify these interrelationships is a deficiency in the planning of the GMAW process. This paper presents a solution method that overcomes this deficiency and introduces a convenient knowledge representation scheme. The solution method considers the planning procedure to be a constraint satisfaction problem (CSP). The AC-4 algorithm is used to obtain arc consistency among nodes in the constraint network and the PC-4 algorithm is applied to obtain path consistency in the network. A modified version of the AC-4 algorithm is developed to reduce the search space and correspondingly reduce the computation time. An example is presented to demonstrate the capability of the method and its potential to reduce lead time.     

Neutral poly(3,4-ethylenedioxythiophene-2,5-diyl)s: preparation by organometallic polycondensation and their unique p-doping behavior

Neutral and non-doped poly(3,4-ethylenedioxythiophene), PEDOTh(Ni), and its hexyl derivative, PEDOTh-C₆(Ni), have been prepared by organometallic dehalogenation polycondensation of 2,5-dichloro-3,4-ethylenedioxythiophene and its hexyl derivative with a zerovalent nickel complex. PEDOTh-C₆(Ni) was soluble in organic solvents and ¹H NMR data indicated that it had an M_n of 11,000. MALDI-TOF mass analysis of PEDOTh(Ni) gave M_n and M_w of about 1700 and 2400, respectively. PEDOTh-C₆(Ni) showed a UV-Vis absorption peak at 546 nm in CHCl₃. Electrochemical oxidation of PEDOTh-C₆(Ni) started at about −0.40 V vs Ag⁺/Ag and gave a peak at 0.20 V vs Ag⁺/Ag. Chemical and electrochemical oxidation (or p-doping) of PEDOTh-C₆(Ni), both in solutions and in a solid state, led to weakening of the original π-π^∗ peaks and rise of new peak(s) in a region of 800-1500 nm. The p-doping of PEDOTh-C₆(Ni) caused not only a decrease in the intensity of ¹H NMR signals of the bridging ethylene hydrogens but also a decrease in that of the hexyl side chain, suggesting a strong interaction of the p-dopant with the side chain. NMR data of poly(3-methoxythiophene-2,5-diyl) also supported an assumption that p-doping brings about a severe change in electronic state of the substituent attached to the polythiophene main chain. PEDOTh(Ni) had a density of 1.71 g cm⁻³; the molecular packing mode of PEDOTh(Ni) is discussed based on the density of the polymer and its XRD data.     

Adaptive predictive control algorithm based on Laguerre Functional Model

Laguerre Functional Model has many advantages such as good approximation capability for the variances of system time‐delay, order and other structural parameters, low computational complexity, and the facility of online parameter identification, etc., so this model is suitable for complex industrial process control. A series of successful applications have been gained in linear and non‐linear predictive control fields by the control algorithm based on Laguerre Functional Model, however, former researchers have not systemically brought forward the theoretical analyses of the stability, robustness, and steady‐state performance of this algorithm, which are the keys to guarantee the feasibility of the control algorithm fundamentally. Aimed at this problem, we introduce the principles of the Incremental Mode Linear Laguerre Predictive Control (IMLLPC) algorithm, and then systemically propose the theoretical analyses and proofs of the stability and robustness of the algorithm, in addition, we also put forward the steady‐state performance analysis. At last, the control performances of this algorithm on two different physical industrial plants are presented in detail, and a number of experimental results validate the feasibility and superiority of IMLLPC algorithm. Copyright © 2005 John Wiley & Sons, Ltd.     

C5/C6异构化催化剂的首次工业应用

采用中石化金陵分公司研究院研制的CI-50(Pd/丝光沸石)作C5/C6烷烃异构化催化剂.详细介绍了该催化剂的工业放大试验装置的工艺流程、首次开工过程中技术问题及处理方法.     

水轮机调速器参数自整定遗传算法的研究

水轮机调速器的参数整定直接关系到水轮机调节系统的稳定运行及调节品质，进而会影响到电能的质量.应用可变交叉概率和变异概率的改进遗传算法对水轮机PID调速器参数进行优化，并将改进遗传算法的计算结果进行仿真分析，结果表明，该方法有效地消除了对参数初值的依赖性，使得寻优效率大大提高，改善了收敛性，是一种较好的PID参数寻优方法。