Study on phase behavior–impact strength relationship of unsaturated polyester/polyurethane hybrid polymer network

The phase behavior of a hybrid polymer network (HPN) composed of poly[(propylene glycol maleate)-co-(propylene glycol phthalate)] crosslinked with styrene and polyester–urethane crosslinked with methylene-bis-ortho-chloroaniline was examined. The correlation between phase separation and impact strength of the HPNs is discussed. The composition of HPNs has an effect on their properties.     

Cying for Me, Cying for Us: Relational Dialectics in a Korean Social Network Site

This study employs a relational dialectics approach to gain insights into the nature of relational communication via Cyworld , a Korean social network site. Qualitative analysis of in-depth interview data from 49 users suggests that Cyworld users routinely negotiate multiple dialectical tensions that are created within the online world, transferred from face-to-face contexts, or imposed by interpersonal principles that relate to Korea's collectivistic culture. The interviewees experienced a new relational dialectic of interpersonal relations versus self-relation, analogous to Baxter and Montgomery's (1996) connection-autonomy contradiction. Their responses suggest that Cyworld's design features and functions encourage users to transcend the high-context communication of Korean culture by offering an alternative channel for elaborate and emotional communication, which fosters the reframing of relational issues offline. Cy-Ilchons (online buddies) virtually extend the Korean cultural concept of blood ties, called yons, in ways that intensify the openness-closedness contradiction at early stages of relationship formation.     

Parasitic Bipolar Junction Transistors in a Floating-Gate MOSFET for Fluorescence Detection

In this letter, we examined whether the parasitic bipolar junction transistors (BJTs) in the MOSFET fabricated by the standard CMOS process can play a role as a fluorescence detector. To suppress the action of two vertical parasitic BJTs, the gate and n-well were tied in the parasitic BJTs, and the body node was connected to the drain. The proposed device was compared with the inherent and the parasitic diodes in the MOSFET. It had 100 times higher photocurrents than the diodes in the MOSFET. In addition, it was applied for the detection of the fluorescent signal, and could detect near 10 nM of Alexa 546. Therefore, CMOS-process-compatible parasitic BJTs can be used as a photodetector in an integrated fluorescence detector.     

朴素的认识

2月20日，“中国国际建筑艺术实践展”项目开工典礼在南京珍珠泉佛手湖工地现场举行。此时距这个项目正式启动已经过了一年半了。从主办方提供的资料看．参展建筑师的设计方案可谓各具特色，但也许正是这种有意为之的特色使得建筑真的成了一件展品。如果说迪斯尼乐园里那些城堡和尖塔是孩子们的大玩具的话，那么佛手湖畔这将要建成的24栋建筑就是成人们的大玩具。     

Thermal stratification and reactor piping integrity

Thermal stratification, cycling, and striping phenomena have drawn much attention recently because of the incidents at several nuclear plants that raised significant safety concerns. The concerns due to these phenomena relate to thermal fatigue in branch pipes connected to the main coolant piping. Nuclear utility industry is addressing the issue with the aim to understand the mechanisms that lead to fatigue in nominally stagnant piping systems near the reactor coolant piping. Two key results from this effort are described in this paper. First, tests to investigate the interaction between the main coolant piping and the stagnant attached lines by turbulence penetration are described and a working correlation is obtained. Turbulence penetration into unisolable lines, or the transport of turbulence into stagnant piping from the reactor coolant system (RCS) line, represents a mechanism for carrying hot RCS water into regions filled with cold water. The possibility of stratification of the two fluids (and the resultant thermal stresses) is the reason for developing an understanding of the turbulence penetration process. Secondly, results of an evaluation to develop a loading definition for thermal striping are included. Based on this testing several important conclusions relating to fatigue in nominally static reactor coolant systems are reached.     

The dynamic effects and compensation of load transitions in robotic systems

The problem of a robot handling a payload typically involves pre-load, load, and post-load stages, and payload transitions between these stages. Although considerable work has focused on the control of robots carrying payloads, few consider the problem of load transitions—one of the most important effects on system performance. This article studies these transitions and presents a compensation method. It is shown that load transitions lead to abrupt (jump) parameters and uncertain transition times in the robot/payload model. A control strategy is proposed that takes the load transitions into account and guarantees the stable path tracking of robots in the face of these transitions. The effectiveness of the proposed control strategy is verified via simulation. © 1994 John Wiley & Sons, Inc.     

Effects of Sc2O3 and MgO passivation layerson the output power of AlGaN/GaN HEMTs

The low temperature (100°C) deposition of Sc₂O₃ or MgO layers is found to significantly increase the output power of AlGaN/GaN HEMTs. At 4 GHz, there was a better than 3 dB increase in output power of 0.5×100 μm² HEMTs for both types of oxide passivation layers. Both Sc₂ O₃ and MgO produced larger output power increases at 4 GHz than conventional plasma-enhanced chemical vapor deposited (PECVD) SiN_x passivation which typically showed ⩽2 dB increase on the same types of devices. The HEMT gain also in general remained linear over a wider input power range with the Sc₂O₃ or MgO passivation. These films appear promising for reducing the effects of surface states on the DC and RF performance of AlGaN/GaN HEMTs