Boundary element analysis of thermal stress intensity factors for interface griffith and cusp cracks

The thermal stress intensity factors for interface cracks of Griffith and symmetric lip cusp types under vertical uniform heat flow in a finite body are calculated by the boundary element method. The boundary conditions on the crack surfaces are insulated or fixed to constant temperature. The relationship between the stress intensity factors and the displacements on the nodal point of a crack-tip element is derived. The numerical values of the thermal stress intensity factors for an interface Griffith crack in an infinite body are compared with the previous solutions. The thermal stress intensity factors for a symmetric lip cusp interface crack in a finite body are calculated with respect to various effective crack lengths, configuration parameters, material property ratios and the thermal boundary conditions on the crack surfaces. Under the same outer boundary conditions, there are no appreciable differences in the distribution of thermal stress intensity factors with respect to each material property. However, the effect of crack surface thermal boundary conditions on the thermal stress intensity factors is considerable.     

掺杂铁电纳米粉的液晶的电光特性

铁电纳米粒子悬浮在向列相液晶母体中，增强介电各向异性，而且对施加的电场信号敏感。本文也展示了纳米粒子对所述复合材料可实现的总的相变的作用。这种方法也许可应用于设计新型显示材料。     

Trenched‐Sinker LDMOSFET (TS‐LDMOS) Structure for 2 GHz Power Amplifiers

This paper proposes a new LDMOSFET structure with a trenched sinker for high‐power RF amplifiers. Using a low‐temperature, deep‐trench technology, we succeeded in drastically shrinking the sinker area to one‐third the size of the conventional diffusion‐type structure. The RF performance of the proposed device with a channel width of 5 mm showed a small signal gain of 16.5 dB and a maximum peak power of 32 dBm with a power‐added efficiency of 25% at 2 GHz. Furthermore, the trench sinker, which was applied to the guard ring to suppress coupling between inductors, showed an excellent blocking performance below ?40 dB at a frequency of up to 20 GHz. These results confirm that the proposed trenched sinker should be an effective technology both as a compact sinker for RF power devices and as a guard ring against coupling.     

Droplet de-entrainment by inertial impaction on vertical rods in an air-droplet mixture flow

We experimentally investigate the de-entrainment of droplets by inertial impaction on an array of vertical rods in an air-droplet mixture flow. The de-entrainment efficiencies are measured for a single rod, for a single row of rods, and for a multi-row of rods. We investigate the effects of the droplet mass flux (0.5–5.4 kg/m² s), the droplet Weber number (3000–8000), the air velocity (0–6 m/s), the rod geometry, and the surface roughness on the de-entrainment, and the rod diameter-to-pitch ratio effect on the de-entrainment. The results for a single rod show that the de-entrainment efficiency decreases slightly as the droplet mass flux increases; however, in our experimental ranges, there is negligible dependence on the droplet Weber number, the air velocity, and the surface roughness. The rod geometry affects the de-entrainment efficiency. The results for a single row of rods show that the existence of neighboring rods promotes de-entrainment due to droplet splashing, and we develop a correlation to show the effect of diameter-to-pitch ratio on the de-entrainment. Using information on the de-entrainment efficiencies of a single rod and those of a single row of rods, we propose a correlation that predicts the de-entrainment efficiency for a multi-row of rods with a staggered array. The RMS errors of the correlation from the de-entrainment efficiencies experimentally obtained are within 13.5%.     

Synthesis and comparative molecular field analysis (CoMFA) of antitumor 3-arylisoquinoline derivatives

In this study a series of 3-arylisoquinoline derivatives were synthesized and cytotoxicity against human melanoma tumor cell evaluated, and a three dimensional quantitative structure-activity relationship was investigated using the comparative molecular field analysis (CoMFA). The results suggested that the electrostatic, steric and hydrophobic factors of 3-arylisoquinolines were strongly correlated with the antitumor activity. Considerable predictive ability (cross-validated r2 as high as 0.721) was obtained through CoMFA.     

A study on crystallization kinetics of pentaerythritol in a batch cooling crystallizer

The crystallization kinetics of pentaerythritol (PeE) in aqueous solution in the presence of impurity or not in a batch cooling crystallizer was explored. Also, the solubility and the nucleation and crystal growth kinetics of PeE in aqueous solution were investigated. A second-order dependence of PeE growth rate on supersaturation is observed in pure PeE-water system. The crystal growth rate of PeE-water system in the presence of impurity is proportional to the supersaturation to the 3.5 power. The nucleation and crystal growth behaviors for PeE-water system in a batch cooling crystallizer were grasped according to Mersmann's criteria. The nucleation in this crystallizer was found to act with heterogeneous nucleation. In this system, it suggests that the crystal growth is controlled by a complex mechanism behavior of surface integrated and diffusion limited. Simplified relation was derived for calculation of mean crystal size of product crystals from the batch cooling crystallizer. The obtained relation was verified by a set of experiments.     

Preparation and characterization of syndiotactic polystyrene/ethylene‐propylene copolymer blends

The reactive compatibilization of syndiotactic polystyrene (sPS)/oxazoline‐styrene copolymer (RPS)/maleic anhydride grafted ethylene‐propylene copolymer (EPR‐MA) blends is investigated in this study. First, the miscibility of sPS/RPS blends is examined by thermal analysis. The cold crystallization peak (T_cc) moved toward higher temperature with increased PRS, and, concerning enthalpy relaxation behaviors, only a single enthalpy relation peak was found in all aged samples. These results indicate that the sPS/RPS blend is miscible along the various compositions and RPS can be used in the reactive compatibilization of sPS/RPS/EPR‐MA blends. The reactive compatibilized sPS/RPS/EPR‐MA blends showed finer morphology than sPS/EPR‐MA physical blends and higher storage modulus (G') and complex viscosity (η*) when RPS contents were increased. Moreover, the impact strength of sPS/RPS/EPR‐MA increased significantly compared to sPS/EPR‐MA blend, and SEM micrographs after impact testing show that the sPS/RPS/EPR‐MA blend has better adhesion between the sPS matrix and the dispersed EPR‐MA phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2084–2091, 2002     

On-line identification of interacting two-tank system

In order to demonstrate the effectiveness of the process identification algorithm, on-line parameter estimator is evaluated experimentally by using two-tank system with interaction. On-line parameter estimator used in this paper is based on a recursive parameter estimation algorithm. MIMO linear, bilinear and quadratic models based on ARMA model are used to identify two-tank system. A quadratic model for two-tank system with interaction is developed to confirm the propriety of MIMO quadratic model used in identification of two-tank system. The results of on-line identification experiments on the two-tank system show that the estimated parameters of each model converge and the output tracking errors are bounded by disturbance bound. But, the quadratic model showed the best convergence.     

Multiple categorizations of products: cognitive modeling of customers through social media data mining

As various forms of social media are spreading, we often witness that an idea of an individual user drives macroscopic changes. From the perspectives of product development and marketing, the opinions left by potential consumers in online social network can generate big ripple effects. This study analyzes the user opinions in online space to grasp preferences toward various products psychologically categorized by users. We also suggest an aspect of the market mentally configured by users using network modeling while following the framework of economic sociology. Existing analyses on online market place are mainly dealing with structural issues such as inter-actor relationships and status measurement. This study, however, analyzes complex preferences regarding diverse products and brands and derives a new model for inter-market connections. We expect that our study will provide important consequences on digital marketing and community design of corporations planning word of mouth effect in online space.     

Synthesis and luminescence properties of new blue‐light‐emitting polyconjugated poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene} polymers and copolymers

Three new soluble polyconjugated polymers, all of which emitted blue light in photoluminescence and electroluminescence, were synthesized, and their luminescence properties were studied. The polymers were poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene}, poly((9,9‐dioctylfluorene‐2,7‐diyl)‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)vinylene‐1,4‐phenylene]}) [P(DOF‐PVP)], and poly([N‐(2‐ethyl) hexylcarbazole‐3,6‐diyl]‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)]vinylene‐1,4‐phenylene}). The last two polymers had alternating sequences of the two structural units. Among the three polymers, P(DOF‐PVP) performed best in the light‐emitting diode devices of indium–tin oxide/poly(ethylenedioxythiophene) doped with poly(styrene sulfonate) (30 nm)/polymer (150 nm)/Li:Al (100 nm). This might have been correlated with the balance in and magnitude of the mobility of the charge carriers, that is, positive holes and electrons, and also the electronic structure, that is, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels, of the polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 307–317, 2006