Organosoluble poly(ether imide)s from phthalimidine based and trifluoromethyl substituted bis(ether amine)

A series of new organosoluble and optically transparent poly(ether imide)s (PEIs) were synthesized by the polycondensation of trifluoromethyl substituted and phthalimidine cardo group based bis(ether amine), 3,3‐bis‐[4‐{2′‐trifluoromethyl 4′‐(4″‐aminophenyl)phenoxy}phenyl]‐2‐phenyl‐2, 3‐dihydro‐isoindole‐1‐one with different fluorinated and non‐fluorinated aromatic dianhydrides (2a–e). All the PEIs were well characterized by elemental analysis, NMR, FTIR spectroscopy, and gel permeation chromatography (GPC). The synthesized PEIs showed moderate to high inherent viscosity 0.41–0.61 dL/g and excellent solubility at room temperature in different organic solvents. All the transparent yellow films showed cut‐off length upto 425 nm. They exhibited high tensile strengths upto 98 MPa, excellent thermostability upto 554°C for 5% weight loss, high glass transition temperature upto 327°C, and water uptake value less than 0.6%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Cadmium Sulfide Aggregates through Reverse Micelles

CdS aggregates, composed of primary nanocrystalline particles, were synthesized in cyclohexane-sorbitan monooleate (Span 80) reverse micelles at 80°± 1°C under mechanical agitation and sonication with varying Cd²⁺ concentrations in the solutions. The critical micelle concentration (CMC) of the surfactant Span 80 in cyclohexane was determined from discernible breaks in the surface tension and optical (ultraviolet) absorbance versus surfactant concentration curves. The synthesized aggregates were characterized using transmission electron microscopy, X-ray diffractometry, particle-size analysis, Fourier-transform infrared spectroscopy, and thermal analyses. The generated aggregates exhibited the characteristic green emission at 520 nm. A minor decrease in emission intensity with increased aggregate size at the same wavelength was observed.     

Internal friction of γ-TiAl alloys at high temperature

Intermetallic γ-TiAl based alloys of engineering interest with respect to high temperature applications are two-phase alloys consisting of γ-TiAl (ordered face-centered tetragonal structure) and ₂-Ti₃Al (ordered hexagonal structure). For this investigation a γ-TiAl based alloy with a composition of Ti-46.4 at%Al-4 at% (Cr, Nb, Ta, B) was studied utilizing a low frequency subresonance apparatus at frequencies between 0.01 and 10 Hz. Above 1000 K, the damping increases strongly up to Q⁻¹=0.2. The frequency and temperature dependence of the high-temperature background was analysed by applying a Maxwell rheological model for viscoelastic relaxation including a distribution of relaxation times. The activation enthalpy of H=3.9 eV agrees well with that from creep experiments (H=3.6 eV) carried out at temperatures between 973 and 1073 K at 200 MPa. The results are discussed in terms of diffusion controlled dislocation climb.     

The neural response to facial attractiveness.

What are the neural correlates of attractiveness? Using functional MRI (fMRI), the authors addressed this question in the specific context of the apprehension of faces. When subjects judged facial beauty explicitly, neural activity in a widely distributed network involving the ventral occipital, anterior insular, dorsal posterior parietal, inferior dorsolateral, and medial prefrontal cortices correlated parametrically with the degree of facial attractiveness. When subjects were not attending explicitly to attractiveness, but rather were judging facial identity, the ventral occipital region remained responsive to facial beauty. The authors propose that this region, which includes the fusiform face area (FFA), the lateral occipital cortex (LOC), and medially adjacent regions, is activated automatically by beauty and may serve as a neural trigger for pervasive effects of attractiveness in social interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

多元文化背景下的家电设计

无论全球化如何发展,固有的文化认同仍然存在,这也对电器的个性化提出了更高的要求。随着城市化的不断发展,城市文化逐渐生根。我们开始以相同的方式生活、工作和游戏。对于电器营销人员来说,     

Designing leakage tolerant, low power wide-OR dominos for sub-130 nm CMOS technologies

In this paper, we discuss the design of leakage tolerant wide-OR domino gates for deep submicron (DSM), bulk CMOS technologies. Technology scaling is resulting in a 3×-5× increase in transistor I_OFF/μm per generation causing 15-30% degradation in the noise margin of high performance domino gates. We investigate several techniques that can improve the noise margin of domino logic gates and thereby ensure their reliable operation for sub-130 nm technologies. Our results indicate that, selective usage of dual V_TH transistors shows acceptable energy-delay tradeoffs for the 90 nm technology. However, techniques like supply voltage (V_cc) reduction or using non-minimum L_e transistors are required in order to ensure robust and low power operation of wide-OR domino designs for the 70 nm generation.     

Variation in the reaction zone and its effects on the strength of diffusion bonded titanium–stainless steel couple

Solid state bonding was carried out between commercially pure titanium and 304 stainless steel at 850 °C temperature for 30–150 min under uniaxial load in vacuum. The transition joints were characterized using optical and scanning electron microscopes and revealed the presence of reaction layers in the diffusion zone. The chemical composition of these reaction products was determined by energy dispersive spectroscopy and the presence of phase/phase mixtures σ, -Fe + χ, χ + λ, λ + FeTi + β-Ti and β-Ti were predicted. Their existence was also confirmed by X-ray diffraction technique. The concentration–penetration plots for Ti, Fe, Cr and Ni are obtained from electron probe microanalysis, which also exhibit concentration gaps in the profile indicating formation of intermetallics in the diffusion zone. The width of intermetallic phases attains its maximum for 90 min joining time, then drops and again rises for 150 min bonding time. The maximum bond strength of 76% of that of titanium was achieved for the assemblies processed for 90 min owing to better coalescence of the mating surfaces, though the volume fraction of intermetallics is high.     

ARC: an integrated admission and rate control framework for competitive wireless CDMA data networks using noncooperative games

The competition among wireless data service providers brings in an option for the unsatisfied customers to switch their providers, which is called churning. The implementation of Wireless Local Number Portability (WLNP) is expected to further increase the churn rate (the probability of users switching the provider). However, the existing resource management algorithms for wireless networks fail to fully capture the far-reaching impact of this unforeseen competitiveness. From this perspective, we first formulate noncooperative games between the service providers and the users. A user's decision to leave or join a provider is based on a finite set of strategies. A service provider can also construct its game strategy set so as to maximize their utility (revenue) considering the churn rate. Based on the game theoretic framework, we propose an integrated admission and rate control (ARC) framework for CDMA-based wireless data networks. The admission control is at the session (macro) level while the rate control is at the link layer packet (micro) level. Two admission control modes are considered - one-by-one mode and batch processing mode, in which multiple users are admitted at a time. We show that: 1) for the one-by-one mode, the Nash equilibrium using pure strategy can be established for both under-loaded and fully-loaded systems and 2) for batch processing mode, there is either an equilibrium in pure strategy or a dominant strategy exists for the service provider. Therefore, the providers have clearly defined admission criteria as outcome of the game. Users are categorized into multiple classes and offered differentiated services based on the price they pay and the service degradation they can tolerate. We show that the proposed ARC framework significantly increases the provider's revenue and also successfully offers differentiated QoS to the users.     

Thalamic thought disorder: on being "a bit addled"

Humans can generate and maintain relatively coherent trains of thought in natural discourse. The neural mediation of this ability and the phenomenology of its breakdown are not well understood. We report a case of a woman with paramedian thalamic strokes involving the mammillothalamic tract, intralaminar nuclei, parts of the dorsomedial and ventral lateral nuclei bilaterally. She presented with a dense amnesia and confusion typical of the syndrome of bilateral paramedian thalamic infarcts. Her Tc-99m HMPAO brain SPECT scan showed decreased thalamic and basal ganglia blood flow. General diminution of cerebral blood flow and areas of further diminution in the right frontal, left temporal and left temporoparietal regions were also observed. Although her amnesia was characteristic of diencephalic amnesia, her most striking clinical feature was a bizarre, disconnected and at times incoherent speech output. Analysis of her speech revealed relatively preserved lexical and morpho-syntactic linguistic production. By contrast, analysis of the macrostructure of her discourse revealed frequent unpredictable topic shifts that were completely unconstrained by contextual factors. Many of her shifts were intrusions from previous topics. We interpret her severely disordered speech output as representing the surface manifestations of a thought disorder (rather than as a language disorder per se) characterized by an inability to maintain and appropriately shift themes that normally guide discourse. Median and intralaminar thalamic nuclei appear to be critical for the neurophysiologic regulation of thalamocortical and striatocortical circuits, which in turn may be critical for the functional regulation of contextually appropriate transitions of thought.