bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of a liquid‐assisted molding process for coating microchannels with an ultraviolet curable polymer
Authors: Boehm Michael W. , Koelling Kurt W.
Published: May 2012

Injection molding can be altered to form hollow parts by partially pre‐filling a mold with polymer melt and then injecting a gas into the mold before cooling. The gas will core the center section and in the process force melt into the unfilled portions of the mold. This process is called gas‐assisted injection molding (GAIM) and is a thoroughly studied polymer processing technique. Liquid‐assisted molding follows the same principles as GAIM, except the coring fluid is a liquid of low viscosity. Liquid‐assisted molding of an ultraviolet (UV) curable polymer can be used to coat microchannels, the benefit of which being a smooth and circular cross‐section. Presented here are experiments of the controlled microchannel flow of a long, immiscible liquid thread through a viscous UV curable polymer. The roles of channel geometry and bubble velocity are discussed for square, rectangular, and circular microchannels. Finally, a quasi‐analytical model for calculating the Newtonian coating fluid thickness, when the coring fluid is driven by a constant pressure, was developed using the equation for Poiseuille‐like flow within a square channel. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Effect of volume ratio of acetonitrile to water on the morphology and property of polypyrrole prepared by chemical oxidation method
Authors: Huang Zhenhao , Hu Shuchun , Zhang Nan , Chen Xiaolang , Chen Dan , Jin Qian , Jian Xian
Published: May 2012

Polypyrrole (PPY) was prepared by the method of chemical oxidation polymerization in ice bath, and a series of products with different morphology or particle size were obtained through changing volume ratio of acetonitrile to water (VRAW) in the mixed reaction solvents. The structures, morphologies, yield, and conductivities of the as‐prepared PPY were characterized by FTIR, SEM, electronic balance, and Four‐probe conductivity meter. Furthermore, the effect of VRAW on the morphology of the obtained PPY was investigated in detail. As shown from the corresponding results, PPY's average diameter decreased with the increase of VRAW in the range of 1:9 to 4:6, with particle morphology; the film‐shaped PPY was obtained when VRAW was in the scope of 5:5 to 7:3. According to the analysis on the polymerization mechanism of pyrrole in the reaction mixture, the change of PPY's morphology was attributed to the structure change of acetonitrile micelle from spherical structure to double layered structure. As the further study shown, the PPY synthesized at a VRAW of 1:9 shows higher yield and conductivity than which prepared in pure water without acetonitrile; however, the further increase of VRAW results in the decrease of the yield and conductivity. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Influence of carbon nanofibers reinforcement on thermal and electrical behavior of polysulfone nanocomposites
Authors: Nayak L. , Khastgir D. , Chaki T.K.
Published: May 2012

Carbon nanofiber (CNF) based polysulfone (PSU) nanocomposites have been developed successfully by a innovative solution mixing technique to explore the effect of state of dispersion and wt% loading of CNFs on different properties of PSU. In order to enhance the interfacial adhesion between CNFs and PSU, CNFs were functionalized by air oxidation. Thermal properties were characterized by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and it was seen that thermal stability of PSU was increased with increase in CNFs loading. The state of dispersion of CNFs throughout the PSU matrix and PSU–CNFs interaction were confirmed using field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) study. The electrical properties of nanocomposites were studied from direct current (DC) and alternating current (AC) resistivity measurement. DC resistivity registered a very low percolation threshold in‐between 0.5–1 wt% of CNFs loading. DC resistivity of PSU was decreased by nine orders of magnitude with the addition of 1 wt% CNFs loading. Dielectric constant and dissipation factor of nanocomposites were significantly increased with increase in CNFs content in nanocomposites. The enhancement in these properties suggests a great potential application of the resulting nanocomposites as multifunctional materials in various electronics industries. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
High‐performance heat‐sink composites incorporating micron‐sized inorganic fillers and Sn/In metal particles
Authors: Hong Jung‐Pyo , Yoon Sung‐Woon , Hwang Taeseon , Oh Joon‐Suk , Hong Seung‐Chul , Lee Youngkwan , Nam Jae‐Do , Bhuiya Md Mainul Hossain , Kim Kwang J.
Published: May 2012

A novel thermal‐barrier composite system was developed by incorporating fusible metal particles in the epoxy matrix system. Using the latent heat of melting, the Sn/In metal particles having melting temperature at 125°C were imbedded in the polymer matrix to suppress the thermal shock and transient temperature variation. The high‐density metal particles were successfully dispersed in the polymer matrix without sinking by incorporating inorganic particles of aluminum nitride (AlN) and boron nitride (BN), which desirably facilitated the heat dissipation to give a high thermal conductivity at around 10 W/m‐K. Under the repeated melting and cooling cycles, the spherical shape of metal particles and the latent heat of melting were retained demonstrating the reversible thermal‐barrier capability of the developed composite system. Under the constant‐heating conditions, it was validated that the temperature rise was delayed by the endothermic melting of Sn/In particles. The developed composite system could find various applications since it could minimize damages caused by the repeated thermal fatigue and/or accidental thermal shock. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Properties and structures of novel cyanate ester/organic rectorite nanocomposites
Authors: Yuan Li , Gu Aijuan , Liang Guozheng , Ma Xiaoyan , Lin Chao , Chen Feng
Published: May 2012

Organic rectorite (OREC) was applied to bisphenol A dicyanate ester (BADCy) resin to develop a novel BADCy/OREC system. The influence of OREC on the reactivity of BADCy was discussed. The morphologies of cured BADCy/OREC systems were investigated by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The static and dynamic mechanical properties as well as the hot water resistance of cured BADCy/OREC systems were evaluated. Results indicate that the addition of OREC can catalyze the reaction of BDACy resin. The intercalated structure and exfoliated structure of silicate platelets may be formed in the cured BADCy/OREC composites. The suitable amount of OREC canimprove the flexural strength, the impact resistance and the hot water resistance of cured BADCy. OREC can maintain the glass transition temperature (Tg) and have slight influence on the dielectric property of cured BADCy. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Mesua ferrea L. seed oil‐based hyperbranched shape memory polyurethanes: Effect of multifunctional component
Authors: Kalita Hemjyoti , Karak Niranjan
Published: May 2012

The bio‐based hyperbranched polyurethanes (HBPUs) have generated immense interest as advanced shape memory materials. In the present investigation, HBPUs were synthesized from poly(ε‐caprolactone)diol as a macroglycol, butanediol as a chain extender, monoglyceride of Mesua ferrea L. seed oil as a bio‐based chain extender, triethanolamine as a branch‐generating moiety (at different percentages), and toluene diisocyanate by a prepolymerization technique using A2 + B3 approach. The structure of the synthesized HBPU was characterized by different techniques. Nuclear magnetic resonance (proton) study indicated the formation of highly branched structure with degree of branching 0.9. The increment of thermal stability from 225 to 260°C and melting point from 50 to 53.5°C with the increase of triethanolamine content was observed. Tensile strength 4–8 MPa, elongation at break 614–814%, impact resistance 0.8–0.95 m, and scratch hardness 2–6 kg increased with the increase of multifunctional moiety content from 0 to 5 wt%. The shape recovery ratio increased with the increase of multifunctional moiety content from 0.21 to 0.95. Thus, the studied HBPUs have the potential to be used as advanced thermoresponsive shape memory materials. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Synthesis of modified silica spheres used for the preparation of dual ultraviolet‐ and thermo‐cured epoxyacrylate/silica composites
Authors: Su Yu‐Chieh , Cheng Liao‐Ping , Don Trong‐Ming
Published: May 2012

To investigate the interfacial effect on properties of epoxyacrylate–silica composites, submicron‐sized silica spheres were synthesized by sol–gel reaction under a basic environment and their surfaces were endowed with vinyl functional groups by further modification with 3‐methacryloxypropyl trimethoxy silane. The pure silica (PS) and the modified silica (MPS) spheres were characterized by Fourier transform infrared, 29Si‐ and 13C‐nuclear magnetic resonance (NMR), scanning electron microscope (SEM), and particle size analyzer. The silica spheres were then added to the presynthesized difunctional epoxyacrylate resin with one vinyl group and one epoxide group at each end, in addition to the photo‐ and thermo‐curing agents. After cure, thermal and mechanical properties of the obtained epoxyacrylate–silica composites were measured and compared. Tensile mechanical properties including initial modulus, ultimate tensile strength, and elongation at break, as well as the fracture energy of the epoxyacrylate–silica composite were all increased by increasing the content of silica spheres. Moreover, the composites filled with MPS had stronger interfacial strength between silica sphere and matrix than those with PS and thus exhibited an additional increase of tensile mechanical properties and fracture toughness. The increase of fracture toughness was owing to the crack deflection and particle–matrix debonding as evidenced by SEM pictures on the fracture surface. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Role of 2‐hydroxyethyl end group on the thermal degradation of poly(ethylene terephthalate) and reactive melt mixing of poly(ethylene terephthalate)/poly(ethylene naphthalate) blends
Authors: Blanco Ignazio , Cicala Gianluca , Restuccia Carmelo Luca , Latteri Alberta , Battiato Salvatore , Scamporrino Andrea , Samperi Filippo
Published: May 2012

In an attempt to minimize the acetaldehyde formation at the processing temperatures (280–300°C) and the outer–inner transesterification reactions in the poly (ethylene terephthalate) (PET)–poly(ethylene naphthalate) (PEN) melt‐mixed blends, the hydroxyl chain ends of PET were capped using benzoyl chloride. The thermal characterization of the melt‐mixed PET–PEN blends at 300°C, as well as that of the corresponding homopolymers, was performed. Degradations were carried out under dynamic heating and isothermal conditions in both flowing nitrogen and static air atmosphere. The initial decomposition temperatures (Ti) were determined to draw useful information about the overall thermal stability of the studied compounds. Also, the glass transition temperature (Tg) was determined by finding data, indicating that the end‐capped copolymers showed a higher degradation stability compared to the unmodified PET and, when blended with PEN, seemed to be efficient in slowing the kinetic of transesterification leading to, for a finite time, the formation of block copolymers, as determined by 1H‐NMR analysis. This is strong and direct evidence that the end‐capping of the OH chain ends influences the mechanism and the kinetic of transesterification. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Crystallization behavior and mechanical strength of poly(butylene succinate‐co‐ethylene glycol)‐based nanocomposites using functionalized multiwalled carbon nanotubes
Authors: Tan Licheng , Chen Yiwang , Zhou Weihua , Ye Suwen
Published: May 2012

Biodegradable poly(butylene succinate‐co‐ethylene glycol) (PBSG)/multiwalled carbon nanotube (MWCNT) nanocomposites were successfully prepared through physical blending and silication between PBSG and acyl aminopropyltriethoxysilane functionalized multiwalled carbon nanotube (MWCNT‐APTES). Nuclear magnetic resonance (NMR) spectra observations revealed that the PBSG chains were covalently attached to the MWCNT‐APTES by hydrolysis. PBSG/MWCNT‐APTES nanocomposites after hydrolysis showed excellent interfacial compatibility between PBSG and MWCNT‐APTES, which was helpful for the dispersion of MWCNT in the PBSG matrix. The incorporation of MWCNT‐APTES accelerated the crystallization of PBSG in the nanocomposites for both approaches of physical blending and hydrolysis due to the heterogeneous nucleation effect of MWCNT while the crystal structure of PBSG was remained. Furthermore, the crystallization rate of PBSG in PBSG/MWCNT‐APTES nanocomposites after hydrolysis was slower than that in the nanocomposite by physical blend. The tensile strength and modulus of the nanocomposites increased about 6% and 11% with the addition of only 1 wt% MWCNT‐APTES compared with that of neat PBSG, and was larger for the PBSG/MWCNT‐APTES nanocomposites after hydrolysis. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Organ Accumulation in Mice After Inhalation of Single or Mixed Essential Oil Compounds
Authors: Satou Tadaaki , Takahashi Mizuho , Kasuya Hikaru , Murakami Shio , Hayashi Shinichiro , Sadamoto Kiyomi , Koike Kazuo
Published: May 2012

Essential oils are composed of multiple components. It is thought that the effect of essential oils is due to specific component ratios, which may differ from the original ratio when the essential oil is absorbed. However, very little detailed research exists in this area. We studied the distribution of essential oil components after inhalation of single and mixed components in mice. This research was done using four main components of Alpinia zerumbet (Pers.) B. L. Burtt. and R. M. Sm.: α‐pinene, p‐cymene, 1,8‐cineole, and limonene. After inhalation of single or mixed components for 90 min, component levels in the brain and liver of mice were measured. The results indicated that the amount of α‐pinene in the brain and liver was twofold greater after mixed‐component inhalation than that after single‐component inhalation. In a comparison of the components of the mixed inhalation, the ratio of α‐pinene increased to about three times that of 1,8‐cineole. It is thought that the absorption via the nasal mucus greatly influences this phenomenon. The results of this investigation of the bodily distribution of essential oil volatile components may provide clues for elucidating their action. Copyright © 2012 John Wiley & Sons, Ltd.
MORE EXOTIC AND FEWER NATIVE PLANT SPECIES: RIVERINE VEGETATION PATTERNS ASSOCIATED WITH ALTERED SEASONAL FLOW PATTERNS
Authors: Greet J. , Cousens R. D. , Webb J. A.
Published: May 2012

Natural flow regimes are important for sustaining riverine vegetation. The regulation of river flows to provide water for agriculture often results in changes to flow timing. This study assesses the impact of altered seasonal flow patterns on riverine flora.

Within temperate Australia, we surveyed the vegetation of five lowland rivers, three of which have large dams that alter their seasonal flow patterns; the other two are unregulated. From four to six sites were selected on each river, and these were classified into three levels of regulation based on the extent to which the timing of their seasonal flow patterns were altered. Sites were surveyed in winter and the following summer. Permanent quadrats were also established at a number of the surveyed sites and resurveyed every 3 months.

Of the 267 plant taxa identified, 145 were exotic (non‐native). More exotic taxa and fewer native taxa were associated with increasing level of seasonal flow inversion (regulation). In particular, greater numbers of short‐lived exotic terrestrial taxa and fewer native woody taxa were associated with increasing level of regulation. Some exotic woody species (e.g. willows) were more common in the unregulated rivers and may have life‐history traits favoured by the natural seasonal flow patterns of study area. Multivariate analyses showed that level of regulation had a significant effect on the overall composition of the riverine vegetation.

Our results provide support for the hypotheses that flow regulation adversely affects native species diversity and increases the vulnerability of riparian zones to invasion by exotic species; however, these effects are dependent on plant species' life‐history strategies. Our study highlights the importance of natural seasonal flow patterns for sustaining native riverine plant communities. Flow management aimed at maintaining or restoring ecological values should consider seasonal flow patterns. Winter/spring flow peaks may be particularly important for the recruitment of native riverine plants, especially trees and shrubs, and reducing the extent of exotic annuals and grasses. Copyright © 2012 John Wiley & Sons, Ltd.
Critical window for the vacant set left by random walk on random regular graphs
Authors: Černý Jiří , Teixeira Augusto
Published: May 2012

We consider the simple random walk on a random d ‐regular graph with n vertices, and investigate percolative properties of the set of vertices not visited by the walk until time
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}\left\lfloor un \right\rfloor\end{align*} \end{document}, where u > 0 is a fixed positive parameter. It was shown in Černý et al., (Ann Inst Henri Poincaré Probab Stat 47 (2011) 929–968) that this so‐called vacant set exhibits a phase transition at u = u⋆: there is a giant component if u < u⋆ and only small components when u > u⋆. In this paper we show the existence of a critical window of size n‐1/3 around u⋆. In this window the size of the largest cluster is of order n2/3. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013
Sharp load thresholds for cuckoo hashing
Authors: Fountoulakis Nikolaos , Panagiotou Konstantinos
Published: May 2012

The paradigm of many choices has influenced significantly the design of efficient data structures and, most notably, hash tables. Cuckoo hashing is a technique that extends this concept. There, we are given a table withnlocations, and we assume that each location can hold one item. Each item to be inserted chooses randomlyk≥ 2 locations and has to be placed in any one of them. How much load can cuckoo hashing handle before collisions prevent the successful assignment of the available items to the chosen locations? Practical evaluations and theoretical analysis of this method have shown that one can allocate a number of elements that is a large proportion of the size of the table, being very close to 1 even for small values ofksuch as 4 or 5.

In this paper we show that there is a critical value for this proportion: with high probability, when the amount of available items is below this value, then these can be allocated successfully, but when it exceeds this value, the allocation becomes impossible. We give explicitly for eachk≥ 3 this critical value. This answers an open question posed by Mitzenmacher (ESA '09) and underpins theoretically the experimental results. Our proofs are based on the translation of the question into a hypergraph setting, and the study of the related typical properties of randomk‐uniform hypergraphs.© 2012 Wiley Periodicals, Inc. Random Struct., 2012
Context Memory in Korsakoff’s Syndrome
Authors: Kessels Roy P. C. , Kopelman Michael D.
Published: May 2012

Memory for contextual information and target-context integration are crucial for successful episodic memory formation and are impaired in patients with Korsakoff’s syndrome. In this paper we review the evidence for the notion that a context memory deficit makes an important contribution to the amnesia in these patients. First, we focus on anterograde memory for contextual (spatial and temporal) information. Next, the use of contextual cues in memory retrieval is examined and their role in retrograde amnesia and confabulation. Evidence on the role of contextual cues and associations in working memory is discussed in relation to the underlying neurocognitive mechanisms and their dissociation from long-term encoding. Finally, we focus on implicit learning of contextual information in Korsakoff patients. It can be concluded that Korsakoff patients are impaired in the explicit processing of contextual information and in target-context binding, both in long-term (retrograde and anterograde) memory and in working memory. These results extend the context memory deficit hypothesis. In contrast, implicit contextual learning is relatively preserved in these patients. These findings are discussed in relation to evidence of dysfunction of the extended diencephalic-hippocampal memory circuit in Korsakoff’s syndrome.
Data Quality Challenges in Systemic Lupus Erythematosus Trials: How Can This Be Optimized?
Authors: Pike Marilyn C. , Kelley Lexy
Published: May 2012

Major scientific advances in basic science, pharmacology, and translational medicine have allowed the discovery of new molecular targets whose manipulation by new chemical entities has led to treatments for inflammatory diseases, including rheumatoid arthritis, multiple sclerosis, and inflammatory bowel disease. Development of new agents for systemic lupus erythematosus (SLE) has lagged, however, because the protean manifestations of SLE present challenges for measuring therapeutic effects in a consistent manner. Composite end points combining several Disease Activity Indices (DAIs) are being used in ongoing global studies, but the uniform application of these complex DAIs across large numbers of clinical sites has proven difficult. We describe herein approaches that are being utilized to facilitate collection, review, and analysis of the clinical measures utilizing independent central adjudication committees.
Tuning adaptive computations for the performance improvement of applications in JEE server
Authors: Zhang Ying , Huang Gang , Liu Xuanzhe , Mei Hong
Published: May 2012

With the increasing use of autonomic computing technologies, a Java Enterprise Edition (JEE) application server is implemented with more and more adaptive computations for self-managing the Middleware as well as its hosted applications. However, these adaptive computations consume resources such as CPU and memory, and can interfere with the normal business processing of applications at runtime due to resource competition, especially when the whole system is under heavy load. Tuning these adaptive computations from the perspective of resource management becomes necessary. In this article, we propose a tuning model for adaptive computations. Based on the model, tuning is carried out dynamically by upgrading or degrading the autonomic level of an adaptive computation so as to control its resource consumption. We implement the RSpring tuner and use it to optimize autonomic JEE servers such as PkuAS and JOnAS. RSpring is evaluated on ECperf and RUBiS benchmark applications. The results show that it can effectively improve the application performance by 13.6 % in PkuAS and 19.2 % in JOnAS with the same amount of resources.
Expression of BMP‐2 and Ets1 in BMP‐2‐stimulated mouse pre‐osteoblast differentiation is regulated by microRNA‐370
Authors: Itoh Tomohiro , Ando Masashi , Tsukamasa Yasuyuki , Akao Yukihiro
Published: May 2012

MicroRNAs (miRs) regulate several biological functions such as cell growth, cell differentiation, and carcinogenesis, by binding to the 3′‐untranslated regions (3′‐UTR) of specific target genes, in order to repress translation or promote degradation of the transcribed mRNAs. In the present study, using microRNA array and in silico analyses, we found that miR‐370 regulates the expression of bone morphogenetic protein‐2 (BMP‐2) and V‐ets Erythroblastosis Virus E26 Oncogene Homolog 1 (Ets1) in BMP‐2‐stimulated murine pre‐osteoblast MC3T3‐E1 cell differentiation. The enforced expression of mature miR‐370 in MC3T3‐E1 cells or primary osteoblast cells remarkably attenuated BMP‐2‐induced pre‐osteoblast differentiation. To ascertain the mechanisms underlying the regulation of osteoblast differentiation by miR‐370, we hypothesized a BMP‐2‐Ets1‐PTHrP feed‐forward loop regulatory mechanism.
I Like Your Product When I like My Photo: Misattribution Using Interactive Virtual Mirrors
Authors: Cho Hyejeung , Schwarz Norbert
Published: May 2012

Recent technological advances in interactive marketing allow consumers to use a ‘virtual mirror’ (created with their own digital photo uploaded to a retailer's Web site) to see how products would look on them. The virtual mirror can be used for simulated product experiences in virtual shopping environments (e.g., trying a garment or a pair of sunglasses in an Internet shopping mall). To enhance our understanding of the managerial implications of this new marketing tool, we test whether the images consumers select to construct their ‘virtual mirror’ influence their product evaluations. Psychological theorizing suggests that it is difficult to distinguish one's reaction to the product from one's reaction to the personal image to which the product is applied, giving rise to misattribution effects. Consistent with this assumption, three studies show that consumers evaluate a product more favorably the more they like the image used to construct a virtual mirror (for themselves or for someone they personally know); the variables used to enhance consumers’ liking of their virtual mirror include the consumer's own facial expression (Study 1), a visual enhancement of the image (Study 2), and a regular vs. mirror image format (Study 3).
Effects of Monetary Incentives on Task Switching
Authors: Kleinsorge Thomas , Rinkenauer Gerhard
Published: May 2012

In two experiments, effects of incentives on task switching were investigated. Incentives were provided as a monetary bonus. In both experiments, the availability of a bonus varied on a trial-to-trial basis. The main difference between the experiments relates to the association of incentives to individual tasks. In Experiment 1, the association of incentives to individual tasks was fixed. Under these conditions, the effect of incentives was largely due to reward expectancy. Switch costs were reduced to statistical insignificance. This was true even with the task that was not associated with a bonus. In Experiment 2, there was a variable association of incentives to individual tasks. Under these conditions, the reward expectancy effect was bound to conditions with a well-established bonus-task association. In conditions in which the bonus-task association was not established in advance, enhanced performance of the bonus task was accompanied by performance decrements with the task that was not associated with a bonus. Reward expectancy affected mainly the general level of performance. The outcome of this study may also inform recently suggested neurobiological accounts about the temporal dynamics of reward processing.
Inferences From Counterfactual Threats and Promises
Authors: Egan Suzanne M. , Byrne Ruth M. J.
Published: May 2012

We examine how people understand and reason from counterfactual threats, for example, “if you had hit your sister, I would have grounded you” and counterfactual promises, for example, “if you had tidied your room, I would have given you ice-cream.” The first experiment shows that people consider counterfactual threats, but not counterfactual promises, to have the illocutionary force of an inducement. They also make the immediate inference that the action mentioned in the “if” part of the counterfactual threat and promise did not occur. The second experiment shows that people make more negative inferences (modus tollens and denial of the antecedent) than affirmative inferences (modus ponens and affirmation of the consequent) from counterfactual threats and promises, unlike indicative threats and promises. We discuss the implications of the results for theories of the mental representations and cognitive processes that underlie conditional inducements.
A Multisensory Interaction Effect in the Conceptual Realm of Time
Authors: Ouellet Marc , Román Antonio , Santiago Julio
Published: May 2012

Recent studies on the conceptualization of abstract concepts suggest that the concept of time is represented along a left-right horizontal axis, such that left-to-right readers represent past on the left and future on the right. Although it has been demonstrated with strong consistency that the localization (left or right) of visual stimuli could modulate temporal judgments, results obtained with auditory stimuli are more puzzling, with both failures and successes at finding the effect in the literature. The present study supports an account based on the relative relevance of visual versus auditory-spatial information in the creation of a frame of reference to map time: The auditory location of words interacted with their temporal meaning only when auditory information was made more relevant than visual spatial information by blindfolding participants.
Confirming Expectations in Asymmetric and Symmetric Social Hypothesis Testing
Authors: Rusconi Patrice , Sacchi Simona , Toscano Armando , Cherubini Paolo
Published: May 2012

This article examines individuals’ expectations in a social hypothesis testing task. Participants selected questions from a list to investigate the presence of personality traits in a target individual. They also identified the responses that they expected to receive and the likelihood of the expected responses. The results of two studies indicated that when people asked questions inquiring about the hypothesized traits that did not entail strong a priori beliefs, they expected to find evidence confirming the hypothesis under investigation. These confirming expectations were more pronounced for symmetric questions, in which the diagnosticity and frequency of the expected evidence did not conflict. When the search for information was asymmetric, confirming expectations were diminished, likely as a consequence of either the rareness or low diagnosticity of the hypothesis-confirming outcome. We also discuss the implications of these findings for confirmation bias.
The Testing Effect as a Function of Explicit Testing Instructions and Judgments of Learning
Authors: Jönsson Fredrik U. , Hedner Margareta , Olsson Mats J.
Published: May 2012

During study, people monitor their learning; the output of this monitoring is captured in so-called judgments of learning (JOLs). JOLs predict later recall better if they are made after a slight delay, instead of immediately after study (the delayed JOL effect). According to the self-fulfilling prophecy (SFP) hypothesis delayed JOLs are based on covert retrieval attempts from long-term memory, and successful retrieval attempts in themselves enhance learning (the testing effect). We compared memory for 40 Swahili-Swedish paired associates after a week as a function of three different learning conditions, namely study plus (i) explicitly instructed self-testing, (ii) delayed JOLs, or (iii) less self-testing. We showed that repeated delayed JOLs lead to a memory improvement that does not differ significantly from a comparable condition where the participants are explicitly testing memory, and both the latter groups performed reliably better than a group that self-tested less. The results suggest that delayed JOLs improve long-term retention as efficiently as explicit memory testing and lend support to the SFP hypothesis.
Integrating the Irrelevant Sound
Authors: Moeller Birte , Rothermund Klaus , Frings Christian
Published: May 2012

A distractor can be integrated with a target response and the subsequent repetition of the distractor can facilitate or hamper responding depending on whether the same or a different response is required, a phenomenon labeled distractor-response binding. In two experiments we used a priming paradigm with an identification task to investigate influences of stimulus grouping on the binding of irrelevant stimuli (distractors) and responses in audition. In a grouped condition participants heard relevant and irrelevant sounds in one central location, whereas in a non-grouped condition the relevant sound was presented to one ear and the irrelevant sound was presented to the other ear. Distractor-based retrieval of the prime response was stronger for the grouped compared to the non-grouped presentation of stimuli indicating that binding of irrelevant auditory stimuli with responses is modulated by perceptual grouping.
Utilities in the 2-4-6 Task
Authors: Vallée-Tourangeau Frédéric
Published: May 2012

The Wason 2-4-6 task was embedded in a practical reasoning scenario where number sequences had well-defined utilities in the process of achieving a goal. Reasoners’ hypothesis-testing behavior was clearly goal-driven and was significantly influenced by whether the utilities favored positive or negative sequences. In the version of the scenario where generating positive sequences had greater benefits than generating negative ones, participants performed poorly at the task as measured by their ability to guess the correct rule and by the nature and number of triples tested before making an announcement. In contrast, the scenario that assigned a greater utility to the production of negative sequences fostered significantly more diligent and creative hypothesis-testing behavior, and participants were significantly more likely to discover the rule. These results suggest that the poor performance observed in Wason’s traditional 2-4-6 task reflects a hypothesis-testing process that by default assigns greater utility to the production of sequences that conform to the initial triple, and hence receive positive feedback. However, reasoners are not averse to producing negative sequences, and understand their implication, if their utility is made relevant in the process of achieving goals.
Interplay between intrachain and interchain interactions in semiconducting polymer assemblies: The HJ-aggregate model
Authors: Yamagata H. , Spano F. C.
Published: May 2012

A new model for analyzing the photophysics of polymer aggregates is introduced taking into account exciton motion along a polymer chain and across polymer chains. Excitonic coupling and vibronic coupling are treated on equal footing using a Holstein-based Hamiltonian represented in a multi-particle basis set. In the HJ-aggregate model the competition between intrachain (through-bond) coupling leading to Wannier-Mott excitons, and interchain (through-space) coupling leading to Frenkel excitons, is studied in detail for two model dimers: one composed of red-phase polydiacetylene (PDA) chains and the other composed of regioregular P3HT chains. The resulting photophysical properties are shown to depend critically on the relative magnitudes of the intrachain and interchain exciton bandwidths. Dominant intraband (interband) coupling favors a photophysical response resembling J-aggregates (H-aggregates). In PDA dimers, where intrachain coupling prevails, the absorption spectrum is dominated by the 0-0 peak, as is characteristic of J-aggregates. The photoluminescence (PL) spectrum displays hybrid character: the ratio of the main (0-0) band to the first vibronic sideband intensities is initially zero at T = 0 K due to the forbidden nature of the 0-0 transition, but then increases with temperature in a manner characteristic of H-aggregates, peaking when kT ≈ ΔE, where ΔE is the interchain splitting. Further increases in temperature result in a decline of the PL ratio, as in a J-aggregate. This remarkable H to J transition is also predicted for the temperature dependence of the radiative decay rate, krad. The maximum (peak) rate scales as, $k_{rad}^{max} \sim (W_{\it intra} /W_{inter})^{1/2} $kradmax∼(Wintra/Winter)1/2, where Wintra (Winter) is the intrachain (interchain) exciton bandwidth. Hence, when Wintra is sufficiently larger than Winter the dimer displays thermally activated superradiance. In P3HT the intrachain coupling is far weaker than in PDA making the intrachain and interchain couplings comparable in the crystalline phase. Although the absorption spectral line shape is still well-accounted for by the conventional H-aggregate model, the photoluminescence is more sensitive, with H or J behavior tunable by changes in morphology. Long range intrachain order which coincides with weaker interchain interactions induces J-aggregate behavior, while short range intrachain order and the resulting stronger interchain coupling induces H-aggregate behavior. Our predictions neatly account for the H-like dominance exhibited by the PL from spin-cast films and the J-like dominance exhibited by the PL from highly ordered P3HT nanofibers self-assembled in toluene.
Structural and spectroscopic study of the van der Waals complex of CO with HCO+ and the isoelectronic complex of CS with HCS+
Authors: Cotton C. Eric , Francisco Joseph S. , Linguerri Roberto , Mitrushchenkov Alexander O.
Published: May 2012

This work reports the results of high level ab initio calculations of the OC-HCO+ complex and the SC-HCS+ complex and their hydrogen migration transition states. Geometry optimizations are performed at the CCSD(T)/aug-cc-pV5Z level of theory. Subsequent frequency calculations are carried out at the CCSD(T)/aug-cc-pVQZ level of theory. Additional geometry optimizations and harmonic frequency calculations for all the species involved in this study have been done with the explicitly correlated CCSD(T)-F12 method with the aug-cc-pVTZ and VTZ-F12 basis set. The geometries, rotational constants, harmonic vibrational frequencies, and energetics of the species involved in the complex are reported. These methods result in accurate computational predictions that have mean deviations for bond lengths, rotational constants, and vibrational frequencies of 0.001 Å, 163 MHz, and 46 cm−1, respectively. These results provide essential spectroscopic properties for the complexes that can facilitate both laboratory and interstellar observations, and they also provide a comparison between oxygen and sulfur complex observability based on thermodynamic stability.
Identification of the dimethylamine-trimethylamine complex in the gas phase
Authors: Du Lin , Lane Joseph R. , Kjaergaard Henrik G.
Published: May 2012

We have identified the dimethylamine-trimethylamine complex (DMA-TMA) at room temperature in the gas phase. The Fourier transform infrared (FTIR) spectrum of DMA-TMA in the NH-stretching fundamental region was obtained by spectral subtraction of spectra of each monomer. Explicitly correlated coupled cluster calculations were used to determine the minimum energy structure and interaction energy of DMA-TMA. Frequencies and intensities of NH-stretching transitions were also calculated at this level of theory with an anharmonic oscillator local mode model. The fundamental NH-stretching intensity in DMA-TMA is calculated to be approximately 700 times larger than that of the DMA monomer. The measured and calculated intensity is used to determine a room temperature equilibrium constant of DMA-TMA of 1.7 × 10−3 atm−1 at 298 K.
The absorption spectrum of D2: Ultrasensitive cavity ring down spectroscopy of the (2–0) band near 1.7 μm and accurate ab initio line list up to 24 000 cm−1
Authors: Kassi Samir , Campargue Alain , Pachucki Krzysztof , Komasa Jacek
Published: May 2012

Eleven very weak electric quadrupole transitions Q(2), Q(1), S(0)-S(8) of the first overtone band of D2 have been measured by very high sensitivity CW-cavity ring down spectroscopy (CRDS) between 5850 and 6720 cm−1. The noise equivalent absorption of the recordings is on the order of αmin ≈ 3 × 10−11 cm−1. By averaging a high number of spectra, the noise level was lowered to αmin ≈ 4 × 10−12 cm−1 in order to detect the S(8) transition which is among the weakest transitions ever detected in laboratory experiments (line intensity on the order of 1.8 × 10−31 cm/molecule at 296 K). A Galatry profile was used to reproduce the measured line shape and derive the line strengths. The pressure shift and position at zero pressure limit were determined from recordings with pressures ranging between 10 and 750 Torr. A highly accurate theoretical line list was constructed for pure D2 at 296 K. The intensity threshold was fixed to a value of 1 × 10−34 cm/molecule at 296 K. The obtained line list is provided as supplementary material. It extends up to 24 000 cm−1 and includes 201 transitions belonging to ten v-0 cold bands (v = 0–9) and three v-1 hot bands (v = 1–3). The energy levels include the relativistic and quantum electrodynamic corrections as well as the effects of the finite nuclear mass. The quadrupole transition moments are calculated using highly accurate adiabatic wave functions. The CRDS line positions and intensities of the first overtone band are compared to the corresponding calculated values and to previous measurements of the S(0)-S(3) lines. The agreement between the CRDS and theoretical results is found within the claimed experimental uncertainties (on the order of 1 × 10−3 cm−1 and 2% for the positions and intensities, respectively) while the previous S(0)-S(3) measurements showed important deviations for the line intensities.
A product branching ratio controlled by vibrational adiabaticity and variational effects: Kinetics of the H + trans-N2H2 reactions
Authors: Zheng Jingjing , Rocha Roberta J. , Pelegrini Marina , Ferrão Luiz F. A. , Carvalho Edson F. V. , Roberto-Neto Orlando , Machado Francisco B. C. , Truhlar Donald G.
Published: May 2012

The abstraction and addition reactions of H with trans-N2H2 are studied by high-level ab initio methods and density functional theory. Rate constants were calculated for these two reactions by multistructural variational transition state theory with multidimensional tunneling and including torsional anharmonicity by the multistructural torsion method. Rate constants of the abstraction reaction show large variational effects, that is, the variational transition state yields a smaller rate constant than the conventional transition state; this results from the fact that the variational transition state has a higher zero-point vibrational energy than the conventional transition state. The addition reaction has a classical barrier height that is about 1 kcal/mol lower than that of the abstraction reaction, but the addition rates are lower than the abstraction rates due to vibrational adiabaticity. The calculated branching ratio of abstraction to addition is 3.5 at 200 K and decreases to 1.2 at 1000 K and 1.06 at 1500 K.
Electronic spectra of the jet-cooled 1-methylvinylthio radical
Authors: Nakajima Masakazu , Miyoshi Akira , Sumiyoshi Yoshihiro , Endo Yasuki
Published: May 2012

Electronic spectra of the $\tilde B - \tilde X$B̃−X̃ transition of the 1-methylvinylthio radical were observed in a discharged jet of propylene sulfide by laser-induced fluorescence spectroscopy. Identification of the spectral carrier was made by comparing the observed spectra with results of molecular orbital calculations, in particular, for vibrational frequencies, rotational contour simulations, and the Franck-Condon simulations. Vibrational structures observed in the electronic spectra indicate that the 1-methylvinylthio radical can be regarded as a molecule with Cs symmetry at the zero-point levels of both the excited and ground states.
Laser induced modification and ablation of InAs nanowires
Authors: He Jiayu , Chen Pingping , Lu Wei , Dai Ning , Zhu Da-Ming
Published: May 2012

InAs nanowires were irradiated locally under an ambient condition using a focused laser beam, which led to laser ablation and thinning of the nanowires. We show that the laser beam can induce a reduction of the local As concentration in an InAs nanowire; the change leads to a significant decrease of local melting temperature of InAs, which results in the thinning and eventually breaking of the nanowire. The results indicate that chemical and mechanical modifications of an InAs nanowire can be accomplished by using a confocal laser beam, which may prove to be a convenient approach in fabricating nanostructural materials and nanodevices.
Ultrafast carrier response of Br+-irradiated In0.53Ga0.47As excited at telecommunication wavelengths
Authors: Fekete L. , Němec H. , Mics Z. , Kadlec F. , Kužel P. , Novák V. , Lorinčík J. , Martin M. , Mangeney J. , Delagnes J. C. , Mounaix P.
Published: May 2012

We present results of infrared pump—terahertz probe experiments applied to a set of In0.53Ga0.47As films irradiated with heavy ions (Br+) at doses from 109 to 1012 cm−2. Photoexcitation at 1400 nm (0.89 eV) allowed us to characterize the response close to telecommunications’ wavelengths whilst avoiding the intervalley carrier scattering observed when a shorter wavelength excitation is used. The excitation fluence was varied in our experiments in order to characterize the dynamics in detail: the lifetimes and mobilities of both electrons and holes were retrieved, and the trap filling and carrier diffusion were clearly observed. The In0.53Ga0.47As film irradiated by the dose of 1012 cm−2 exhibits simultaneously ultrashort electron lifetime (∼300 fs) and very high electron mobility (2800 cm2V−1s−1). These findings are particularly important for the design of terahertz emitters controlled by lasers operating at standard telecommunication wavelengths.
Magnetism, magnetoresistance, and Shubnikov-de Haas oscillations in Na-implanted highly oriented pyrolitic graphite
Authors: Pires R. F. , Pureur P. , Behar M. , Pimentel J. L. , Schaf J. , Kopelevich Y.
Published: May 2012

We report on magnetization, magnetoresistance, and Shubnikov-de Haas oscillations experiments in Na-implanted samples of highly oriented pyrolitic graphite (HOPG). Different ion fluences were applied so that samples with Na contents of 0.5, 1.0, 1.5, and 2.0 at. % were obtained in the implanted region. Ferromagnetic-like hysteresis was observed in magnetization experiments where the field was applied parallel to the graphene planes. The observed saturation moment increases systematically as a function of the implanted ion concentration up to Na 1 at. %, where it goes through a maximum before decreasing slightly towards Na 2 at. %. The planar magnetoresistance amplitude at fixed field and temperature closely correlates with the saturation magnetization data. This result suggests that the strong planar magnetoresistance in graphite is at least partially related to a spin dependent mechanism. The magnetoresistance experiments also reveal the occurrence of Shubnikov-de Haas oscillations. The characteristic frequencies and the effective masses could be estimated and do not depend on the Na concentration. The reported experiments show that the expressive enhancement observed in ferromagnetic-like response in Na-implanted HOPG is primarily due to point defects produced by the implantation process.
Growth of highly oriented YSZ and CeO2 films with Tasker-forbidden surfaces in oxygen-deficient environments
Authors: Zhang Xiaojun , Kronawitter Coleman X. , Berdahl Paul , Mao Samuel S.
Published: May 2012

Yttria-stabilized zirconia and cerium dioxide thin films are deposited in oxygen-deficient environments and compared to those deposited in oxygen-rich environments. Oxygen-deficient films are highly (001)-oriented, which corresponds to a surface that should be forbidden based on Tasker’s theoretical calculation. Oxygen-vacancy-induced surface reconstruction and relaxation are proposed to explain the phenomenon. The analysis is consistent with preferred orientations previously observed in indium tin oxide, SnO2, and NiO films. Detailed studies of preferred orientations of these oxygen-deficient metal oxide films are of importance for their use in solid oxide fuel cells, gas sensors, and optical devices, etc.