热喷涂技术的现状和发展

介绍了热喷涂工艺的特点，喷涂方法的种类及其技术以及热喷涂技术的应用概况，并对热喷涂技术的发展方向给予了展望。     

光子选通光谱烧孔的全息检测与图像存贮

报道在有机光子选通光谱烧孔材料苯基四苯并卟啉锌/芳晴系统中，进行全息光谱烧孔和图像存贮的实验结果．实验表明全息烧孔极大地提高了光谱孔的检测灵敏度和信噪比．通过全息光子选通光谱烧孔，成功地进行了光子选通型的频率选择的多幅全息图存贮，得到清晰的图像再现 关键词：     

一个包含Smarandache函数的方程

对于任意正整数n,我们用S(n)表示Smarandache函数,即S(n)=min{m:n|m!}.本文的主要目的是运用初等方法研究方程∑_(d|n)S(d)=n的可解性,并给出它的所有正整数解.     

Cluster and periodic DFT calculations of adsorption and activation of CO2 on the Cu(hkl) surfaces

The adsorption behavior and thermal activation of carbon dioxide on the Cu(1 1 1), Cu(1 0 0), and Cu(1 1 0) surfaces have been investigated by means of density functional theory calculations and cluster models and periodic slabs. According to the cluster models, the optimized results indicate that the basis set of C and O atoms has a distinct effect on the adsorption energy, but an indistinct one on the equilibrium geometry. For the CO₂/Cu(hkl) adsorption systems studied here, the final structure of adsorbed CO₂ is near linear and the preferred modes for the adsorption of CO₂ onto the Cu(1 1 1), Cu(1 0 0), and Cu(1 1 0) surfaces are the side-on adsorption at the cross bridge site with an adsorption energy of 13.06 kJ/mol, the side-on adsorption at the short bridge site (13.54 kJ/mol), and the end-on adsorption on the on-top site with C–O bonds located along the short bridge site (26.01 kJ/mol), respectively. However, the calculated adsorption energies from periodic slabs are lower as compared to the experimental data as well as the cluster model data, indicating that the periodic slab approach of generalized gradient approximation in the density function theory may be not suitable to obtain quantitative information on the interaction of CO₂ with Cu(hkl) surfaces.     

质子滴线区新的缓发质子先驱核121Ce

藉助核反应⁹²Mo(³²S ,3n)产生了未知的缓发质子先驱核¹²¹Ce ,并利用氦喷嘴快速带传输系统和“p-γ”符合方法对它进行了鉴别 .测定了¹²¹Ce的半衰期 ( 1.1±0 .1 )s,观测了它的β缓发质子能谱 ,粗略地估计了它的β缓发质子衰变道的分支比约为1% .首次观测了先驱核¹¹⁹Ba,¹²¹Ba和¹²²La经过β缓发衰变在“子核”中产生的低位能级到基态的γ 跃迁.     

70个南天旋涡星系等值厚度的测定

利用彭秋和提出的方法以及分析星系的旋涡图样 ,得到 70个南天旋涡星系的等值厚度 ,这些星系的图象是从北京天文台兴隆观测站Palomar天图数字光盘 (theDigitizedSkySurvey)中读出的 .为了得到星系的最佳倾角 (星系平面与天球切平面之间的夹角 ) ,把用最小二乘法拟合得到的对数螺线画在星系图象上与旋臂进行比对 ,反复调节星系的倾角 ,使拟合得到的对数螺线能很好地与旋臂吻合 ,从而得出星系的最佳倾角.     

积分方程的ε复杂性

本文考虑积分方程的ε复杂性问题.问题的ε复杂性是在误差不超过ε的前提下解决问题所需的最小成本.对某些具各向异性核与自由项的第二类Fredholm方程,求得了ε复杂性的精确阶.同时,找到了解决该问题具最小成本的算法.     

First Total Synthesis of 12-Hydroxy-13-methylpodocarpa-9, 11, 13-trien-3-one

12-Hydroxy-13-methylpodocarpa-9, 11, 13-trien-3-one 9 was isolated from the twigs ofCroton salutaris1. Many diterpenes exhibit significant bioactivities, such as antibac-terial and antitumour and 9 has a rare structure. In order to study the relationshipb…     

Crosslinked epoxy materials exhibiting thermal remendablility and removability from multifunctional maleimide and furan compounds

Crosslinked polymeric materials, which exhibit thermal remendability and removability through Diels–Alder (DA) and retro‐DA reactions, were obtained from using multifunctional maleimide and furan compounds as monomers. The synthesized monomers possess low melting points and good solubility in organo solvents to show excellent processing properties. The performance of DA and retro‐DA reactions were demonstrated with DSC and FTIR measurements. High performance of thermal remendablility and removability of the crosslinked materials were observed with SEM and solvent tests. These materials were applicable in advanced encapsulants and structural materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 905–913, 2006     

Sulfonated poly(aryl ether ether ketone ketone)s containing fluorinated moieties as proton exchange membrane materials

A series of sulfonated poly(aryl ether ether ketone ketone)s statistical copolymers with high molecular weights were synthesized via an aromatic nucleophilic substitution polymerization. The sulfonation content (SC), defined as the number of sulfonic acid groups contained in an average repeat unit, could be controlled by the feed ratios of monomers. Flexible and strong membranes in sodium sulfonate form could be prepared by the solution casting method, and readily transformed to their proton forms by treating them in 2 N sulfuric acid. The polymers showed high T_gs, which increased with an increase in SC. Membranes prepared from the present sulfonated poly(ether ether ketone ketone) copolymers containing the hexafluoroisopropylidene moiety (SPEEKK‐6F) and copolymers containing the pendant 3,5‐ditrifluoromethylphenyl moiety (SPEEKK‐6FP) had lower water uptakes and lower swelling ratios in comparison with previously prepared copolymers containing 6F units. All of the polymers possessed proton conductivities higher than 1 × 10^?2 S/cm at room temperature, and proton conductivity values of several polymers were comparable to that of Nafion at high relative humidity. Their thermal stability, oxidative stability, and mechanical properties were also evaluated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2299–2310, 2006