Miscible blends of poly(n-vinyl-2-pyrrolidone) with poly(3-chloropropyl methacrylate), poly(2-bromoethyl methacrylate) and poly(2-iodoethyl methacrylate)

Summary Poly(N-vinyl-2-pyrrolidone) is miscible with poly(3-chloropropyl methacrylate), poly(2-bromoethyl methacrylate) and poly(2-iodoethyl methacrylate) as shown by the optical clarity and the glass transition behaviour of the blends. The miscible blends degrade before phase separation could be induced by heating. The three T_g-composition curves can be fitted by the Gordon-Taylor equation. The implication of the Gordon-Taylor k parameters of the blends is discussed.     

Driving a Wedge Between Evidence and Beliefs: How Online Ideological News Exposure Promotes Political Misperceptions

This article has 2 goals: to provide additional evidence that exposure to ideological online news media contributes to political misperceptions, and to test 3 forms this media‐effect might take. Analyses are based on representative survey data collected during the 2012 U.S. presidential election (N = 1,004). Panel data offer persuasive evidence that biased news site use promotes inaccurate beliefs, while cross‐sectional data provide insight into the nature of these effects. There is no evidence that exposure to ideological media reduces awareness of politically unfavorable evidence, though in some circumstances biased media do promote misunderstandings of it. The strongest and most consistent influence of ideological media exposure is to encourage inaccurate beliefs regardless of what consumers know of the evidence.     

Problematic Instant Messaging Use

This study is an empirical investigation of problematic instant messaging (IM) use among university students in Singapore. It adapts Caplan's (2005) theoretical framework of problematic Internet use (PIU) to the context of problematic IM use by linking pre-existing human dispositions to cognitive-behavioral symptoms and negative outcomes of improper IM use. Four new factors—oral communication apprehension, polychronicity, perceived inconvenience of using offline communication means, and trait procrastination—were tested as predictors of problematic IM use. The results provided strong support for Caplan's theoretical framework of PIU and indicated that oral communication apprehension and perceived inconvenience of using offline means were significant predictors of problematic IM use, whereas polychronicity and trait procrastination were not. The implications of these findings are discussed.     

搞定双核处理器“变”单核的问题

不久前笔者购买了一台电脑,采用Intel Pentium E2180双核处理器,在现场验机时,看到开机自检信息和系统属性中均显示出正确的处理器型号,于是就打包拿回了家。不料再开机使用时才发现,任务管理器中只有一颗核心的占用率信息（正常应该是两颗）,而且在CPU-Z和Everest检测软件中均显示处理器型号为Intel Pentium E2180,但核心却只有一个（图1、图2）。难道双核处理器也有假货吗？     

Small PWRs using coated particle fuel for district heating, PFPWR50

It has been said that nuclear energy is an important option for especially developing countries to satisfy their increasing energy demand. However, it will be difficult to deploy first of a kind nuclear power plant in developing countries because extensive safety demonstration has to be conducted in industrialized countries. On the other hand, it will be essential to present rigid proof of reliable operational experience to develop proper understanding of the safety features of new reactor systems among the people around the demonstration plant sites. One of the ways to solve the issue is to integrate existing technologies supported by a great deal of data and experience into a new reactor design. Based on the consideration, a small-sized district heating reactor system based on the pressurized water reactor (PWR) technologies combined with the fuel concept of high temperature gas cooled reactors (HTGRs) has been studied. The purpose of the combination of these two existing concepts is to take the best advantages of both excellent operational experience of PWRs and the integrity of HTGR fuel, coated particle fuel, against fission products release even at high temperature. We expect that this approach will help create a breakthrough to the current stagnation of nuclear power deployment.     

EFFECTS OF COOLANT SUPPLY METHODS AND CUTTING CONDITIONS ON TOOL LIFE IN END MILLING TITANIUM ALLOY

Titanium machining poses a great challenge to cutting tools due to its severe negative influence on tool life primarily due to high temperature generated and strong adhesion in the cutting area. Thus, various coolant supply methods are widely used to improve the machining process. On account of this, tool life and cutting force are investigated based on dry cutting, flood cooling, and minimum quantity lubrication (MQL) techniques. The experimental results show that MQL machining can remarkably and reliably improve tool life, and reduce cutting force due to the better lubrication and cooling effect.     

Hydrogel‐mediated formation of living cartilage template for endochondral initiation

The use of hydrogel in cartilage tissue engineering is especially popular due to its high hydrophilic property which is similar to native cartilage matrix. Alginate hydrogel was used as a transient scaffold material to facilitate chondrocyte proliferation into a three‐dimensional scaffold‐free living hyaline cartilaginous graft (LhCG). As LhCG is purely cell‐based and has a marked resemblance to native hyaline cartilage, it served as an excellent in vitro platform for studying the endochondral ossification pathway. Due to the complexity of events involved throughout endochondral ossification, this study only focuses on early stages of the process where it involves chondrocyte hypertrophy and blood vessel invasion. Human umbilical vein endothelial cells (HUVECs) were selected as the target cells for possible endothelialization in the LhCG template. They were seeded onto the LhCG construct and subjected to vascular endothelial growth factor (VEGF) treatment. Results suggested that VEGF is indeed a potent driving force for initiation of the endochondral pathway. It alone is sufficient to induce hypertrophy in chondrocytes and the corresponding expression of osteogenic genes with or without the presence of HUVECs in the LhCG template. On the other hand, the effect of HUVECs in the LhCG system was less evident. It is hypothesized that this is attributed to the preservation of anti‐angiogenic properties in primary chondrocytes from the LhCG construct, inhibiting HUVECs from endothelialization in the LhCG+HUVEC construct. Based on the outcome from this study, it is recommended that hypertrophy in chondrocytes should be induced prior to endothelial cell introduction so that the microenvironment will be altered to favor angiogenesis within the cartilaginous template. © 2013 Society of Chemical Industry     

Spiral column configuration for protein separation by high-speed countercurrent chromatography

Retention of the stationary phase of aqueous–aqueous polymer phase systems is improved by a spiral column configuration which utilizes the radially acting centrifugal force along the spiral pitch to retain the heavier phase in the outer portion and the lighter phase in the inner portion of the spiral channel. For the separation of proteins which has low mass transfer rates, the system needs further modification of the separation channel to interrupt the laminar flow and enhance mixing of the two phases.     

Thermal stability in high-T c coil and magnet design by process control of Bi(Pb)-2223/Ag multifilamentary tapes

It has been found that the degree of thermal stability of Bi(Pb)-2223/Ag pancake-shaped coils at 77 K can be determined by controlling the amount of matrix and superconducting materials during processing. The intermediate deformation step between sintering stages has been found to be crucial in optimizing the performance of the processed composite tapes as well as governing the thermal stability of the subsequently made pancake-shaped coils. Results obtained from numerical analysis of the finite element method has shown that monolayer coils produced from Bi(Pb)-2223/Ag composite tapes are thermally very stable with high values of the fill factor. However, increasing the number of co-wound tapes would require either a reduction in the fill factor or an increase in cooling rate for thermal stability to be sustained as would otherwise be achieved with the metallurgically same single tape.     

A Mixed-Signal Approach Towards Linear and Efficient N-Way Doherty Amplifiers

A mixed-signal approach for the design and testing of high-performance N-way Doherty amplifiers is introduced. In support of this, an analysis of N-way power-combining networks is presented-in particular, their optimum design-by examining the relationship between the drive conditions of the active devices and input power. This analysis makes no prior assumption on the network topology and facilitates free-to-choose levels for the high-efficiency power back-off points. By comparing the results of this analysis with prior work, it is shown that very specific drive conditions apply to traditional three-way Doherty amplifier implementations to obtain simultaneously high-efficiency and high-linearity operation. To support these conclusions, a 15-W three-way Doherty amplifier was constructed using Philips GEN4 LDMOS devices featuring three separate inputs to independently drive the main and peaking devices. By testing this three-way amplifier with a custom-built measurement setup, capable of providing multiple digitally controlled coherent RF input signals with high spectral purity, a unique flexible amplifier concept is created resulting in a record-high efficiency for LDMOS-based Doherty amplifiers over a 12-dB back-off power range