Intracavity Electronic Absorption Spectra of MoO and WO Molecules in the Visible Region

Absorption electronic spectra of MoO and WO molecules have been investigated by a intracavity laser technique in the region 550–800 run. New features have been discovered.

As for MoO molecule the rotational analysis of the four bands have been carried out for the first time. Two of these bands were referred to 0–0 transitions arisen from the new (probable triplet) low-lying electronic state, two other bands were referred to transitions arisen from excited components of X⁵II ground state.

As for WO molecule the rotational analysis of 0–0 and 1–0 bands represented A-X and B-X systems have been carried out for the first time. The new band has been discovered which has been referred to new electronic transition.

Molecular constants of new states of both molecules studied have been evaluated.     

Application of dye-partition technique to the determination of the rates of initiation in radical polymerization

Summary Dye-partition technique as an useful method of measuring kinetic chain length (v), rate of initiation (R _i ), initiator efficiency (f), and the parameter [=(2k _t)^1/2 k _p] etc. in radical polymerization using styrene and methylmethacrylate as monomers in dimethyl formamide medium and 4,4 azobis-4-cyanopentanoic acid as the initiator to produce dye responsive carboxyl ended polymers has been discussed. The values ofR _p,f and obtained by this method compare fairly well with those obtained by a standard method, viz., molecular weight method. The magnitude off much less than unity and constancy in its value under different concentrations of monomers and initiator indicate that almost all radicals surviving geminate recombination is captured by the monomers. The precautions necessary for applying this method have also been discussed.

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Zusammenfassung Farbstoff-Verteilungstechnik als nützliche Methode zur Messung der kinetischen Kettenlänge (v), Initiationsgeschwindigkeit (R _i ), des Initiator-Wirkungsgrades (f), und des Kennwertes (2k,^1/2 k _p ) (=) etc. bei der radikalischen Polymerisation von Styrol und Methylmethacrylat in Dimethylformamid-Medium mit 4,4'-Azobis-4-cyanopentansäure als Initiator zur Bildung von mit Farbstoffen reagierenden Carboxylatendgruppen in den Polymeren, wurde diskutiert. Die durch obengenannte Methode festgestellten Werte vonR _p ),f und sind ungefähr mit den durch übliche Methoden festgestellten Werten vergleichbar (durch Molekulargewicht-Methode).Die konstante Größenordnung von 'f, die viel weniger als eins beträgt, weist darauf hin, daß alle die paarweise Rekombination überlebenden Radikale von den Monomeren abgefangen werden. Die zur Anwendung dieser Methode nötigen Vorsichtsmaßnahmen sind auch diskutiert worden.

     

新型半导体可见光催化剂纳米锰酸钇

采用聚丙烯酰胺凝胶法制备了锰酸钇(YMnO3)纳米颗粒,并运用X射线衍射、扫描电镜和紫外可见漫反射光谱对样品进行了表征.结果表明,制得的YMnO3纳米晶主要为六方钙钛矿结构,兼有少许的正交钙钛矿结构,且颗粒粒度均匀、形貌规整、呈类球形,平均颗粒尺寸约为45 nm.另外,测得YMnO3纳米颗粒的光学带隙值为1.31 eV...     

容量矩阵法在涡方法中的应用

本文将容量矩阵技术与快速Fourier变换相结合求解非矩形域的Poisson方程,再与格子涡方法相结合,发展了一套求解复杂外形的快速涡方法。作为算例,计算了有厚度平板和楔形体的分离流动,得到了满意的结果。特别是在垂直平板绕流中,模拟出了由于剪切层不稳定性引起的小涡结构。     

Conjugated turbulent heat transfer with axial conduction in wall and convection boundary conditions in a parallel-plate channel

The steady-state conjugated turbulent heat transfer with axial conduction in the wall and convection boundary conditions is solved with the generalized integral transform technique for the flow of Newtonian fluid in parallel-plate duct. A lumped wall model that neglects transverse temperature gradients in the solid but that takes into account the axial heat conduction along the wall is adopted. Highly accurate results are presented for the fluid bulk and wall temperatures and Nusselt number. The effects of the conjugation parameter, Biot number, and the dimensionless channel length on Nusselt number and fluid bulk and wall temperatures are systematically investigated.     

云纹干涉制栅新技术

本文介绍了两种新的光栅复制技术,它们具有快速、高质量、低成本、操作简单、使用方便、不需特殊仪器等特点.该技术从我国一般力学实验室条件出发,解决了试件栅制作困难,其中漆栅方法可极大地缩短云纹干涉方法的实验周期,该技术也为光栅测试技术的广泛应用提供了方便.     

转动盘一片系的循环对称模综

本文考察在任意恒定转速下叶片/轮盘系的固有模态分析,计及叶片预扭所引起的大变形效应.把群论算法用于子结构技术,通过联立迭代求出叶片/轮盘系在离心场中的平衡位置和应力分布,进而确定初应力刚度矩阵、大变形刚度矩阵,以及相应的动频模态.由于本方法考虑了叶片大变形的影响,且可消去子结构间的全体内连自由度。从而在确保精度的前提下,显著地压缩了计算的规模.实践证明本文提出的子结构联立迭代法有很好的收敛性,它使计算量有巨大的节省.     

关于湍流拟序结构的思考

本文在简要地回顾了30多年来湍流拟序结构研究的进展之后,评述了目前拟序结构研究的动态。笔者强调准确的湍流场数据库建立的重要性,它是定量描述和研究拟序结构的基础。笔者评述了关于拟序结构目前流行的几种观点和方法,认为应当把研究拟序结构的动力学作为我们研究的目标。笔者深信准确掌握拟序结构的动力学规律,对于预测和控制湍流将有极大的推动。      

A direct relationship between bending waves and transition conditions of floating plates

Ocean waves travel deep into ice fields in the polar regions, both affecting the formation of sea-ice and causing its break-up. Recently, it has been shown that a relatively simple linear water and bending wave theory can predict the decay rate of the wave energy travelling through fractured ice sheets and floes at the geophysically important wave periods of 6–15 s. That work used simple free-edge conditions. A possible improvement to the current model is to better represent the effective connection due to partially frozen cracks that occur in practice. The Wiener–Hopf technique gives explicit formulae for the velocity potential and surface deflection, expressed as series expansions over the modes of the elastic plate floating on water of finite depth, with the coefficients in the expansion given as functions of four constants. These constants are determined by a system of four linear equations, represented by a 4-by-4 matrix and a four-element vector. The elements of the matrix are given as explicit functions of relationship between edge conditions. General connections between ice sheets may be interpreted as a vertical and a rotational spring providing transition conditions for the shear force and the bending moment. The reflection and the transmission of waves can then be simply calculated as direct functions of the connection conditions. Conversely, reflected and transmitted waves allow complete characterization of the effective connection conditions at a material discontinuity.     

钢板-混凝土组合加固钢筋混凝土梁的非线性有限元分析

以10根采用钢板-混凝土组合加固技术加固的钢筋混凝土梁的试验为基础,建立了钢板-混凝土组合加固钢筋混凝土梁的非线性有限元模型.沿用了钢板-混凝土组合梁有限元分析中栓钉的荷载-滑移曲线及断裂模型,提出了新老混凝土界面的剪切-滑移模型,可以较好地模拟界面受力性能.采用有限元软件ABAQUS,模拟了一次加固、不同损伤加固及持载加固等加载情况下加固构件受力全过程和受弯破坏以及新老混凝土剥离破坏等破坏形态下加固试件的受力性能.在验证了有限元模型的准确性后,分析了钢板厚度、加固部分高度及长度等参数对加固构件承载能力及刚度的影响.最后提出了几点对钢板-混凝土组合加固RC梁的设计建议.