High-resolution infrared spectrum of cyanogen

The high-resolution spectrum of cyanogen (¹⁴N¹²C¹²C¹⁴N) has been measured from 500 to 4900 cm⁻¹. For this isotopomer many combination levels with both degenerate fundamentals, ν₄ and ν₅, have been measured for the first time and the effects of vibrational l-type resonance are observed as well as rotational l-type resonance. The effects of the vibrational resonance coupling ν₂ and 2ν₄ have also been studied. The data have been combined with earlier measurements below 500 cm⁻¹ to give a comprehensive catalog of the vibrational energy levels and the rovibrational constants for the normal isotopomer of cyanogen. A comparison of the term value constants for the three major symmetric isotopomers is given and they are compared with a recent ab initio calculation. The present data were combined with earlier work on the two symmetric isotopomers, ¹³C₂¹⁴N₂ and ¹²C₂¹⁵N₂, to obtain the equilibrium bond lengths, r_CC = 138.109(60) pm and r_CN = 115.976(40) pm.     

Role of cleaning methods on bond quality of Ti coated glass/imidex system

Thin film materials are widely used in the fabrication of semiconductor microelectronic devices. In thin film deposition, cleanliness of substrate surface have become critically important as over 50% of yield losses in integrated circuit fabrication are caused by microcontamination [1]. There are many wafer cleaning techniques. The most successful approach for silicon wafer cleaning technique is RCA clean [2]. But for glass substrate it is still not known which procedure of cleaning is the best. This paper provides an understanding of the right way of glass wafer cleaning method, with a focus towards identifying good bond strength. Two wafer cleaning techniques have been used for cleaning glass substrates in the context of laser micro-joining of dissimilar substrates. First cleaning procedure involves two steps, first cleaning in acetone solution and then in DI water solution. After each step dried with N₂. Second cleaning procedure involves four steps, first cleaning with 1% Alconox solution, second in DI water, third in acetone solution and finally in a methanol solution and dried with N₂ after each step. Deposition of Ti thin film on top of these two types of substrate using DC magnetron sputtering method also showed better adhesion of Ti film on glass for the second type of cleaning method. Scanning electron microscopy (SEM) analyses of the lap shear tested failed surfaces for these two kinds of samples revealed strong bond for samples prepared by second cleaning method compared to first cleaning method. Characterization of these two sets of samples using X-ray photoelectron spectroscopy (XPS) has shown excellent contamination removal for the second cleaning method. This modification is believed to be due to reduction of carbon contamination.     

Efficient and selective hydroarylation of propiolic acids and their esters with arenes catalyzed by a PtCl2/AgOTf system

PtCl₂/AgOTf-catalyzed hydroarylation of ethyl propiolate proceeded effectively to give ethyl (2Z)-cinnamate derivatives in good to high yields, without the formation of diethyl (1E,3Z)-4-arylbuta-1,3-diene-1,3-dicarboxylates that was observed in Pd(OAc)₂-catalyzed reaction. Especially, PtCl₂/AgOTf-catalyzed hydroarylation of propiolic acids proceeded effectively to give (2Z)-cinnamic acids exclusively.     

Effects of the bond dilution on the phase diagrams of a spin-1 transverse Ising model with crystal field interaction on a honeycomb lattice

A bond diluted spin-1 Ising model with crystal and transverse field interactions is examined for honeycomb lattice by introducing an effective field approximation that takes into account the correlations between different spins that emerge when expanding the identities. The effects of the crystal field as well as the transverse field and dilution on the phase diagrams and order parameter m_z are discussed in detail. A number of interesting and unusual phenomena such as reentrant phenomena and three successive phase transitions originating from the crystal field as well as the transverse field and bond dilution have been found.     

Magnetic properties of the bond and crystal field dilution spin-3/2 Blume–Capel model in an external magnetic field

Magnetic properties of the bond and crystal field dilution spin-3/2 Blume–Capel model in an external magnetic field (h)$(h)$ on simple cubic lattice are studied by using the effective field theory. In the m−T$m-T$ plane, the degeneracy of the magnetization (m)$(m)$ is affected by the concentration of bond or crystal field dilution at low temperature (T)$(T)$. The magnetization curves can appear to fluctuate in certain regions of negative crystal field. In the m−h$m-h$ plane, the initial magnetization curve has an irregular behavior due to the introduction of bond dilution. The crystal field dilution has the influence on the process of magnetic domain displacement. In the χ−h$\chi -h$ plane, there exists one susceptibility (χ)$(\chi )$ shoulder and one step for different negative crystal field. The susceptibility curve takes on the feature of multi-peaks distribution under bond and crystal field dilution conditions.     

The bond force constants and elastic properties of boron nitride nanosheets and nanoribbons using a hierarchical modeling approach

A hierarchical approach bridging the atomistic and nanometric scales is used to compute the elastic properties of boron nitride nanosheets and nanoribbons, examining the effect of sheet size, aspect ratio and anisotropy. The approach consists in obtaining the bond force (force field) constants by dedicated computations based on density functional theory (DFT) and using such constants as input for larger scale structural models solved by finite element analysis (FEA). The bond force constants calculated by DFT are 616.9 N/m for stretching, 6.27×10⁻¹⁹ Nm/rad² for in-plane rotation and 1.32×10⁻¹⁹ Nm/rad² for dihedral rotation. Using these constants, the elastic properties of boron nitride nanosheets and nanoribbons predicted by FEA are almost independent of the sheet size, but strongly dependent on their aspect ratio. The sheet anisotropy increases with increased aspect ratio, with nanoribbons of aspect ratios of 10 exhibiting a ratio of elastic moduli along both in-plane directions of 1.7.     

Prediction of bond failure and deflection of carbon fiber-reinforced plastic reinforced concrete beams

Carbon fiber-reinforced plastic (CFRP) reinforced concrete beams can fail due to interface debonding, due to the high tensile strength of such rebars. A set of 16 concrete beams reinforced with different amounts of CFRP reinforcement was subject to static three-point bending. The beam dimensions and CFRP reinforcements used were selected to demonstrate a transition from compression failure to bond failure with decreasing reinforcement ratio. It is shown that accurate bond strength data to predict such failures can be obtained from a “hinged-beam” test configuration, rather than the conventional direct “pull-out” tests. Deflection under service loads can also be predicted more accurately using a proposed equation that includes the reinforcement ratio and the elastic modulus of the reinforcement.     

Mechanics of rubber shear springs

FEA calculations have been carried out for a model rubber shear spring, consisting of a block of a highly elastic material, bonded between two rigid parallel plates and sheared by displacing one of the plates parallel to the other in its own plane. The block was prevented from deforming in the perpendicular direction, and thus was deformed in plane strain. Stress distributions along the bond-line and the center-line are reported and compared with those expected from the theory of large elastic deformations. Unexpected tensile stresses were found to develop in the interior of the sheared block. They are attributed to the absence on the end surfaces of the stresses needed to maintain a simple shear, causing a pronounced change in the reference pressure—a consequence that is usually overlooked. Because the internal stresses are governed by the boundary conditions, they were strongly affected by the shape of the end surfaces. In addition, they were reduced markedly by assigning values to Poisson's ratio slightly lower than 0.5, thus allowing some volume expansion of the rubber. Strain energy release rates were also evaluated for growth of a crack along the bond-line, starting at the edges, and compared with those reported previously by Lindley and Teo [Energy for crack growth at the bonds of rubber springs, Plast. Rubber Mat. Appl. 4 (1979) 29-37], Muhr et al. [A fracture mechanics study of natural rubber-to-metal bond failure, J. Adhes. Sci. Technol. 10 (1996) 593-616], Gregory and Muhr [Stiffness and fracture analysis of bonded rubber blocks in simple shear, in: D. Boast, V.A. Coveny (Eds.), Finite Element Analysis of Elastomers, Professional Engineering Publications, Bury St. Edmunds, UK, 1999, pp. 265-274] and Gough and Muhr [Initiation of failure of rubber close to bondlines, in: Proceedings of the International Rubber Conference, Maastricht, Netherlands, June 2005, IOM Communications Ltd., London, 2005, pp. 165-174]. They confirm that a long crack at the compression edge will grow faster than one at the tension edge, but the results for short cracks were inconclusive.     

微重时卧圆柱内静液面方程与数值计算

由力学平衡方程导出了微重时卧圆柱内静液面方程,推出了边界接触角条件,使用Ｒｕｎｇｅ Ｋｕｔａ法在计算机上得出了数值结果,绘出了静液面形状,并对结果进行了分析．     

Modal part analysis of slosh of the liquid in a cylindrical container in the case of small bond number

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