bluuebunny/crossref_metadata_2025 huggingface dataset:
Conversations with I. A. Richards: The Renaissance in Cognitive Literary Studies
Authors: Goodblatt Chanita , Glicksohn Joseph
Published: April 2011

Throughout his career as critic and teacher, I. A. Richards (1893–1979) was involved in various conversations about poetry: those with his students in the course Practical Criticism, which he pioneered at Cambridge in 1925 and which is still being taught today; those of his students and colleagues in the years 1925–28 with the poetic texts he gave them, generated in an experimental procedure and published in part in his book Practical Criticism; and those with students at Harvard University during the years 1944–63. The challenge for us in this present essay is to integrate these varied cognitive literary studies into our own response to Richards, specifically through the empirical study of poetic texts within the tradition of the Gestalt school of psychology. In the first section, we discuss the poem as a gestalt, which stands behind Richards's presentation of the real reader's “poetic experience” in his Principles of Literary Criticism. We exemplify this by developing a particular technique, used by Richards to teach poetry at Harvard, into an empirical study of the haiku form of poetry. In the second section, we explicate Richards's own empirical study of John Donne's “Holy Sonnet 7,” originally presented in Practical Criticism, which is a good example of the renaissance in Donne criticism at the beginning of the twentieth century. Richards's experimental technique is discussed in relation to what was then contemporary experimental psychology. We then compare Richards's study with various subsequent replications, including our own, presented here. In the third section, we try to update Richards's experimental technique of obtaining written protocols to one of obtaining online verbal protocols in response to Donne's poem “The Bait.” The move from reading this poem to its empirical study highlights our integration of the different lines of thought within cognitive literary studies.
In Vitro Cytotoxicity and Intracellular Bioimaging of Dendritic Platinum Nanoparticles by Differential Interference Contrast (DIC)
Authors: Hong Chen-Yu , Yamauchi Yusuke , Wu Kevin C-W
Published: April 2011

We demonstrated the excellent biocompatibility of dendritic platinum nanoparticles (DPNs) in vitro using a cancer cell line (BT-20) and MTT assay. In addition, a successful observation of DPNs within live cells using differential interference contrast (DIC) microscopy without labelling fluorescent dyes has been achieved.
Detentions of older adults under the Mental Health (Care and Treatment) (Scotland) Act 2003
Authors: Stevenson Gary
Published: April 2011

This study prospectively examined all initial emergency and short-term detention orders of older adults under the Mental Health (Care and Treatment) (Scotland) Act 2003 in a Scottish health region in 2008 to determine differences in characteristics and outcomes by patients' age, gender and those detained by consultant compared with non-consultant clinicians. Detention order papers were scrutinized, the detaining practitioners were interviewed and case records were examined. Appropriate statistical analyses were performed. For the 87 detentions, subjects were Caucasian, male (54%) and 45% were aged 80 years or older. Ninety-four percent of detentions occurred on a weekday, during working hours (87%), in hospital (67%) with consultants initiating 74% of orders. Detention rates ranged from 66 to 171 per 100,000 over-65s. Seventy-five percent of patients had an organic disorder, 46% exhibiting psychotic symptoms. The older group had higher rates of confusion, organic diagnoses, but lower levels of previous psychiatric admissions. Consultants were more likely to detain patients with a wider variety of disorders, with more admissions to and detentions in psychiatric hospital care. Final detention outcomes were significantly different between the consultant and non-consultant groups. The results indicated few differences between the genders, but differences were more significant between the age cohorts and were further influenced by the grade of the detaining clinician. Further research is required to examine the influence that community mental health teams, advance statements and the use of guardianship and incapacity legislation have on the increasing rates of mental health detentions in the aging population.
Health Professionals or Policemen?; Error with Nonformulary Drug; Adjust Pradaxa Dose for Renal Impairment; Federal Legislation to Address Drug Shortages; Nicotine-Nitroglycerin Patch Mix-up
Authors: Cohen Michael R. , Smetzer Judy L.
Published: April 2011

These medication errors have occurred in health care facilities at least once. They will happen again—perhaps where you work. Through education and alertness of personnel and procedural safeguards, they can be avoided. You should consider publishing accounts of errors in your newsletters and/or presenting them at your inservice training programs.

Your assistance is required to continue this feature. The reports described here were received through the Institute for Safe Medication Practices (ISMP) Medication Errors Reporting Program. Any reports published by ISMP will be anonymous. Comments are also invited; the writers' names will be published if desired. ISMP may be contacted at the address shown below.

Errors, close calls, or hazardous conditions may be reported directly to ISMP through the ISMP Web site ( www.ismp.org ), by calling 800-FAIL-SAFE, or via e-mail at ismpinfo@ismp.org . ISMP guarantees the confidentiality and security of the information received and respects reporters' wishes as to the level of detail included in publications.
Pioglitazone-lnduced Pancytopenia; Trimethoprim-Sulfamethoxazole-Induced Aseptic Meningitis; Oxcarbazepine-Related Thrombocytopenia Purpura; Beta-Blockers and REM Sleep Behavior Disorders; Beta-Blockers and the Risk of Incident Depression in the Elderly; Two Reports of Central Nervous System Problems with “Marijuana Substitute”; Iatrogenic Glaucoma Secondary to Medications
Authors: Shuster Joel
Published: April 2011

The purpose of this feature is to heighten awareness of specific adverse drug reactions (ADRs), discuss methods of prevention, and promote reporting of ADRs to the US Food and Drug Administration's (FDA's) MedWatch program (800-FDA-1088). If you have reported an interesting, preventable ADR to MedWatch, please consider sharing the account with our readers.
Challenges in the measurement of serum testosterone concentrations as a biomarker of men's health1
Authors: Haring Robin , Spielhagen Christin , Nauck Matthias
Published: April 2011

Male testosterone concentrations gained recent attention in the field of andrology. Various epidemiological cohort studies presented associations of low serum testosterone concentrations with incident cardiovascular risk factors and increased mortality risk. Furthermore, low serum testosterone concentrations are integral part for the diagnosis of late-onset hypogonadism. Because of their high validity and throughput, mass spectrometry assays have replaced conventional immunoassays for testosterone measurement, and are believed to become the "gold standard" for sex hormone quantitation. This article will focus on challenges in the measurement of serum testosterone concentrations and will provide practical information on the interpretation of serum testosterone measurements.
Evaluation of In Situ Characterization Techniques for Pavement Applications of Portland Cement-Stabilized Soil
Authors: Griffin Jonathon R. , Jersey Sarah R.
Published: April 2011

Evaluation of the structural capacity of in-service pavements with a cement-stabilized soil layer provides a unique challenge. Properties required to assess the structural capacity include strength and stiffness of the material. Traditionally these parameters are determined from laboratory testing of samples obtained in situ. Obtaining, transporting, and testing material samples are expensive procedures often not possible due to the low strength of some stabilized blends. The U.S. Army Engineer Research and Development Center investigated the potential of implementing a series of portable tools to rapidly obtain these parameters in the field. Field tests were performed at three sites, and samples were recovered and subjected to laboratory testing. Regression analyses were used to determine the existence of linear relationships between the results of the laboratory and field testing. Statistical analyses were performed to determine the validity of applying select relationships from literature and those developed in this study. The development of a reliable evaluation procedure was hindered by the inherent variability of stabilized materials. However, the devices investigated in this study should be considered for quality control testing on new construction with portland cement-stabilized soil.
Blurring the Lines in Interferon γ Receptor Deficiency: An Infant With Near-Fatal Airway Disease
Authors: Auld Benjamin , Urquhart Donald , Walsh Mark , Nourse Clare , Harris Margaret-Anne
Published: April 2011

Deficiencies of the interferon γ (IFN-γ) pathway have become a well-recognized cause of nontuberculous mycobacterial infection. We report here a case of autosomal dominant IFN-γ receptor 1 (IFN-γ-R1) deficiency presenting at the unusually young age of 16 months with a severe clinical course. Mycobacterium avium complex was cultured from bronchial washings of a child who presented with primary endobronchial disease after a 4-month history of rhinorrhea, wheeze, and acute lobar consolidation. A maternal history of multifocal Mycobacterium kansasii osteomyelitis and cutaneous M avium complex led to genetic confirmation of IFN-γ-R1 818del4 deletion (a 4 base pair deletion at nucleotide position 818) in both family members. This case demonstrates the link between mycobacterial disease and IFN-γ pathway deficiency, the diagnosis of which facilitates more accurate therapy and genetic counseling. The case also raises questions about the reported distinct presentation, treatment, and prognosis of autosomal dominant and recessive IFN-γ-R1 phenotypes.
Influenza A/H1N1 MF59-Adjuvanted Vaccine in Preterm and Term Children Aged 6 to 23 Months
Authors: Esposito Susanna , Pugni Lorenza , Daleno Cristina , Ronchi Andrea , Valzano Antonia , Serra Domenico , Mosca Fabio , Principi Nicola
Published: April 2011

OBJECTIVE:

This study was designed to evaluate the immunogenicity, safety, and tolerability of a monovalent 2009 pandemic influenza A/H1N1 MF59-adjuvanted vaccine in children aged 6 to 23 months who had different gestational ages (GAs) at birth.

METHODS:

The study involved 105 children: 35 preterm subjects with a GA of <32 weeks; 35 preterm subjects with a GA of 32 to 36 weeks; and 35 term subjects with a GA of 37 to 42 weeks. Each child received 2 intramuscular vaccine doses (Focetria [Novartis, Siena, Italy]): dose 1 at enrollment and dose 2 after 4 weeks (28 ± 2 days). Serum samples for antibody measurements were collected immediately before administration of dose 1, before administration of dose 2 (28 ± 2 days after baseline), and 4 weeks later (56 ± 2 days after baseline). Local and systemic reactions were assessed during the 14 days after each vaccination.

RESULTS:

Of the 101 children who completed the study 32 out of 34 preterm subjects with a GA of <32 weeks, all of the preterm subjects with a GA of 32 to 36 weeks, and all of the term subjects seroconverted and were seroprotected after the first vaccine dose. Local and systemic tolerability was good in all of the groups, but fever was significantly more common after the first dose than after the second dose (P < .05), and there were no between-group differences.

CONCLUSIONS:

A single dose of 2009 pandemic influenza A/H1N1 MF59-adjuvanted vaccine evoked a significant immune response against pandemic influenza A/H1N1 virus in children aged 6 to 23 months even if their GA was <32 weeks. The vaccine had a good safety and tolerability profile.
Growth and Characterization of Shape-Controlled Single Crystals by a Micro-pulling-down Method
Authors: Yokota Yuui , Tanaka Hidehiko , Sato Masato , Chani Valery , Tota Kazushige , Onodera Ko , Yanagida Takayuki , Yoshikawa Akira
Published: April 2011

Shape-controlled CaF2 and sapphire crystals were grown by a micro-pulling-down (μ-PD) method and the crystallinities were investigated. By the μ-PD method with crucibles which have special configurations, circular tube-shaped CaF2 crystal, square tube-shaped CaF2 crystal and square tube-shaped sapphire crystal with high transparency were obtained. The grown crystals indicated a single phase of CaF2 and Al2O3 in the XRD measurements. X-ray rocking curve of square tube-shaped sapphire indicated the crystal has no mosaic structure in the crystal and it has high crystallinity comparable to crystals grown by Cz method.
Study of Mechanical Responses and Thermal Expansion of CNF-modified Polyester Nanocomposites Processed by Different Mixing Systems
Authors: Hossain Muhammad E. , Hossain Mohammad K. , Hosur Mahesh , Jeelani Shaik
Published: April 2011

In this study, different dispersion techniques such as sonication at high frequency, mechanical mixing, and magnetic stirring methods were employed to infuse 0.1 to 0.4 wt.% carbon nanofiber (CNF) into polyester matrix to study the influence of CNF on mechanical and thermal properties of the polyester nanocomposites. Dispersion of CNF studied using scanning electron microscopy (SEM) micrographs revealed excellent dispersion of CNF using sonication when 0.2 wt.% CNF was mixed in polyester resulting in enhanced mechanical response. On the other hand, agglomerations were observed in samples prepared with other mixing methods. Polyester with 0.2 wt.% CNF samples prepared by sonication resulted in 88% and 16% increase in flexural strength and modulus, respectively, over neat samples. Quasi-static compression tests showed similar increasing trend with addition of 0.2 wt.% CNF. Dynamic mechanical analysis (DMA) showed 35% and 5 °C improvement in the storage modulus and glass transition temperature (Tg), respectively, in the 0.2 wt.% loaded samples. Thermal mechanical analysis (TMA) performed on neat and samples with 0.2 wt.% CNF showed lower coefficient of thermal expansion (CTE) in nanophased sample compared to neat. Fracture morphology evaluated using SEM revealed relatively rougher surface in CNF-loaded polyester compared to neat as a result of better interaction between fiber and matrix due to the presence of CNF.
In Situ Synthesis and Integration of Polymer Electrolytes in Nanostructured Electrodes for Photovoltaic Applications
Authors: Nejati Siamak , Lau Kenneth K. S.
Published: April 2011

The conventional dye sensitized solar cell (DSSC) is limited by the use of a liquid electrolyte that is prone to leakage and evaporation. Efforts to replace the liquid with a solid equivalent have been met with difficulties in penetrating the mesoporous TiO2 nanostructured photoanode with liquid processing, particularly for photoanode layer thickness greater than 2 μm. Here, initiated chemical vapor deposition (iCVD) is successfully applied to directly synthesize and fill the pores of the mesoporous TiO2 network of up to 12 μm thickness with poly(2-hydroxyethyl methacrylate) (PHEMA) polymer electrolyte. Comparing with equivalent liquid electrolyte cells, DSSCs integrated with PHEMA polymer electrolyte showed consistently higher open circuit voltage, which is attributed to a decrease in electron recombination with the redox couple at the electrode-electrolyte interface.
Magnetic Polypropylene Nanocomposites Reinforced with In-situ Fabricated Iron Oxide Nanoparticles
Authors: Zhu Jiahua , Wei Suying , Guo Zhanhu
Published: April 2011

Polypropylene(PP)/Fe2O3 nanocomposites are fabricated using an in-situ method to uniformly disperse the magnetic nanoparticles (NPs) in polymer matrix. Maleic anhydride functionalized PP (f-PP) with different molecular weight is used as surfactant to stabilize the in-situ produced nanoparticles. The thermal behavior of PP and its nanocomposites with the incorporation of small amount f-PP is studied with thermal gravimetric analysis (TGA). The results show that the onset degradation temperature is increased by ~117 oC with the addition of NPs. Both melt rheology and transmission electron microscopy are used to investigate the NPs dispersion. Strong saturated magnetization (Ms) is observed after introducing f-PP to the nanocomposites through protecting the as-formed NPs from oxidation.
Gelation, Electrical Conductivity and Elasticity of PAM- MWNT
Authors: Evingur Gulsen A. , Pekcan Önder
Published: April 2011

Polyacrylamide- Multiwalled carbonnanotube (PAM- MWNT) composites were prepared via free radical crosslinking copolymerization with different amounts of MWNT varying in the range between 0.1 and 15 wt. %. PAM- MWNT composite gels were characterized by fluorescence, dielectric spectroscopy and the tensile testing technique. A small content of doped nanotubes dramatically changed gelation time, conductivity and young modulus, respectively. The gel fraction exponent,βof PAM- MWNT composite gels were measured for various monomer and MWNT concentrations and observed that the gel fraction exponentβagrees best with the percolation theory for various amounts of PAM- MWNT. These polymer systems which are initially of an isolator character are doped with carbon nanotubes of nano dimensions and when the amount of this addition exceeds a critical value (0.3 wt. % MWNT) known as the percolation threshold, then composite gel systems with carbon nanotubes become electrically conducting structures with a critical exponent aroundr=2 which is close to the theoretical prediction of this value in 3D percolated system as known random resistor network. The observed elasticities are decreased above 3 wt. %MWNT with critical exponent aroundy=0.72 which is indicative of a transition from liquid-like to solid-like viscoelastic behavior.
Microwave Metamaterials Containing Magnetically Soft Microwires
Authors: Panina L. V. , Ipatov M. , Zhukova V. , Estevez J. , Zhukov A.
Published: April 2011

This paper discusses a new type of wire media based on amorphous ferromagnetic microwires. The combination of two effects, namely, a strong dispersion of the effective permittivity in metallic wire composites (resonance or plasmonic type) and giant magnetoimpedance effect in wires will result in unusual property that an effective dielectric response may strongly depend on the wire magnetization which can be changed with different external stimuli. We have demonstrated the effect of the external magnetic field on microwave response from composites containing CoFeSiBCr amorphous wires in free space at microwave frequency.
Melt-Quench Formed Smectic Phase in iPP/CNT Nanocomposites and its Re-Crystallization
Authors: Georgiev Georgi , Cabrera Yaniel , Wielgus Lauren , Schoen Scott , Ivy Devin , Cebe Peggy
Published: April 2011

The largest commercial application of carbon nanotubes (CNT) are their polymer nanocomposites (PNCs). This motivates detailed studies of the interactions between CNTs and polymers and the ways the CNTs influence the crystallization behavior and structure of PNCs. We have chosen isotactic polypropylene (iPP) as one of the best model systems because of its ability to form a smectic liquid crystal phase. We studied iPP/CNT nanocomposites with CNT concentrations ranging from 0.01 to 5% per weight. We prepared films by compression molding and quenching in a mixture of isopropyl alcohol and dry ice. Some of the formed smectic liquid crystalline (LC) phase of iPP/CNT PNCs persisted to temperatures higher than the last melting temperature for iPP crystals. By means of differential scanning calorimetry we corroborated the existence of the LC phase in the nanocomposites and studied the impact of multi-walled carbon nanotubes on its melting and re-crystallization. We used a polarizing optical microscopy to reconfirm our DSC data.
Laser assisted fabrication of porous polymer MEMS with nano structured additives
Authors: Shishkovsky Igor V. , Morozov Yuri G.
Published: April 2011

Selective laser sintering (SLS) process was used to obtain nanostructured porous 3D objects consisting of Ni or/and Cu nanoclusters enveloped with a polycarbonate (PC) matrix for M/NEMS applications. The liquid phase SLS process was performed in air or Ar. The powder mixtures of Ni + PC in proportions 1:1, 1:2 (Ni particle size ranged from 27 to 184 nm) and Cu + PC = 1:9, 1:4, 3:7 (Cu particle size ranged from 76 to 90 nm) and a cw YAG:Nd+3 laser (P = 4–10 W) with defocused laser beam were used. Optimal regimes of laser treatment as monolayer as layerwise 3D part manufacturing in above mention nano compositions were determined. The scanning electronic microscopy (SEM) equipped EDX and qualitative XRD analysis showed that content and size of nanoparticles are remained unaffected after the liquid-phase sintering. It was shown a principle possibility of functional graded 3D parts fabrication via the interleaving of the metal - polymer powdered compositions with Ni and/or Cu additives, which ensures the nano particle sizes conservation. Proposed approach is opened a new way by deliberated M/NEMS device synthesis. Alternation of ferromagnetic and non-magnetic layers with Ni and/or Cu core – polymer shell structures was provided the interesting electro-physical properties of such devices.
Layer-by-layer Stacking Method for 3-D Nano Structure Fabrication Using Block Copolymer Self Assembly
Authors: Warisawa Shin’ichi , Kanameda Ryosuke , Kometani Reo , Ishihara Sunao
Published: April 2011

In this paper, we present layer-by-layer stacking method to fabricate self-assembled structures of block copolymers (BCP) toward the out-of-plane direction. Layer-by-layer stacking is realized by transferring a BCP film on one substrate to another. Specifically, a water-soluble polymer film is coated on the former substrate, which is placed and fixed in contact with a target substrate. Consequently, the BCP film is released from the substrate and transferred to the target substrate when immersed in de-ionized water. In our experiment, PS-b-PMMA is used to form and transfer self-assembled structures, and polyvinyl alcohol is used as a water-soluble polymer. We prepared two kinds of target substrates; one has horizontal cylindrical structures by BCP self assembly, and the other has groove structures by EB lithography. In the case of BCP patterned substrate, BCP film with vertical cylindrical structures is transferred onto the line structures of BCP. In the case of EB lithography patterned substrate, BCP film with vertical cylindrical structures is transferred in a doubly suspended condition. Furthermore, vertical and horizontal cylindrical structures are also observed to align along the grooves.
Crystallization Kinetics in Isotactic Polypropylene Films with Carbon Nanotubes
Authors: Georgiev Georgi , Schoen Scott , Ivy Devin , Wielgus Lauren , Cabrera Yaniel , Cebe Peggy
Published: April 2011

Polymer nanocomposites are the largest commercial application for carbon nanotubes (CNTs) which determines the interest in their effect on crystallization processes of polymers. We chose Isotactic Polypropylene (iPP) as one of the most widely used polymers. Nanocomposites with multiwall carbon nanotubes (MWCNTs) 0-5% by weight were studied, using differential scanning Calorimetry to measure the crystal nucleation and kinetics effects of MWCNTs. Isothermal crystallization at 138°C was performed and the data were analyzed using Avrami analysis. We obtained results for the effect of MWCNTs on the crystallization kinetics. The Avrami analysis showed a dramatic increase in the crystallization rate constant and constancy of the Avrami exponent with increase of the CNTs concentration. The full width at half maximum (FWHM) of the heat flow exotherm and the peak time for crystallization (tp) change dramatically. The crystallinity shows a slight variation with the CNTs concentration dipping at 2% CNTs which can be explored further at higher concentrations.
Long Cycle Life Nanocellulose Polypyrrole Electrodes
Authors: Nyström Gustav , Olsson Henrik , Sjödin Martin , Carlsson Daniel O. , Mihranyan Albert , Nyholm Leif , Strømme Maria
Published: April 2011

A polypyrrole (PPy) nanocellulose composite was shown to cycle well over 3000 cycles in 2.0 M NaCl electrolyte when used as the active material for both electrodes in an energy storage device. SEM micrographs show a highly porous nature of the conductive paper material and electrochemical charge-discharge measurements, as well as external electrode potential monitoring, confirm the good cycling behavior of the material.
The Electrical Conduction at Early Stages of Cluster-Assembled Films Growth
Authors: Barborini Emanuele , Corbelli Gabriele , Milani Paolo
Published: April 2011

Electrical conduction in Fe, Pd, Nb, W and Mo cluster-assembled films was investigated in-situ, during their growth by supersonic cluster beam deposition. We observed for clusterassembled films resistivity values several orders of magnitude larger than corresponding bulk, as well as an increase of resistivity by increasing the film thickness, in contrast to the behaviour of atom-assembled metallic films. This suggests that nanoscale morphology arising by growth dynamics of cluster-assembled films, such as the minimal cluster-cluster interconnection and the evolution of surface roughness with thickness, may play a crucial role in the observed behaviour. Theoretical models based on non-isotropic 3D distributions of clusters into the film would help for a deeper understanding of the behaviour of cluster-assembled films compared to atomassembled ones. Benefits are expected in the technological field of devices performing electrical read-out on active nanostructured layers, as in the case of chemoresistive sensors.
Silicon nanowires solar cell
Authors: Xie Xiaobing , Zeng Xiangbo , Yao Wenjie , Yang Ping , Liu Shiyong , Peng Wenbo , Wang Chao , Zhang Xingwang , Zhu Hongliang , Wang Zhanguo
Published: April 2011

We made an amorphous-silicon (a-Si) solar cell with a nanowire-array structure on stainless steel(SS) by plasma enhanced chemical vapor (PECVD) deposition. This nanowire structure has an n-type Si nanowire array in which a-Si intrinsic layer and p type layer are sequentially grown on the surface of the nanowire. The highest open-circuit voltage (Voc) and short-circuit current density (Jsc) for AM 1.5 illumination were 620 mV and 13.4 mA/cm2, respectively at a maximum power conversion efficiency of 3.57%.
Comprehensive light trapping study of next generation thin film solar cells
Authors: Zhou Zhou , Zhou Jian , Sun Xiaowei , Cheng Tim , Wang Shengqi , Yi Yasha
Published: April 2011

Light trapping is one of the key challenges for the next generation of thin film solar cells. In this work, we have identified the distinct light trapping effects for short and long wavelength solar spectrum ranges, by investigating lighting trapping structures on both sides of Si thin film solar cells. The sub-wavelength moth-eye-like photonic front surface and multi-layer grating photonic crystal reflector on the bottom surface are studied in detail via the Finite Difference Time Domain method for its solar energy absorption characteristics. Our study reveals the drastic difference in the light trapping effects within the solar spectrum wavelength. This work may provide guidance for efficiency enhancement of next generation thin film photovoltaic cells.
Binding of Dinuclear Ruthenium Complexes, SWNTs and Nanoparticles for Hybrid Nanocomposite Materials
Authors: Alston Jeffrey R. , Poler Jordan C.
Published: April 2011

Integration of nanomaterials into composite systems is the next evolutionary step in nanoscale science. Until recently nanocomposites are formed by embedding nanomaterial components into matrices, through chemical bonding or with various wrapping agents. We seek to show that through directed self assembly nanomaterials can be coupled with photosensitizing ruthenium complexes while avoiding chemical augmentation and insulating effects from polymer, surfactant or DNA wrapping. We have synthesized dinuclear ruthenium complexes (dimers) possessing rigid conjugated π-electron systems that form a nanoscale pocket. The pocket is dimensionally suited to interact strongly with nanomaterials forming an architecture that could facilitate photon collection and charge transfer across the interaction. This study explores the binding interaction of our ruthenium dimers with SWNTs. The binding strength varies relative to the magnitude of formal charge which trends with DFT simulations that predict SWNT dimer interactions. SWNT surface saturation by ruthenium dimers can be observed using UV-visible spectroscopy and characterized with adsorption isotherms. We also explore a new technique to measure nanomaterial interactions, isothermal titration calorimetry (ITC). We show that ITC can be used to directly measure the binding enthalpy of nano material surface interactions in solution.
Electrospun Polythiophene Nanofibers and Their Applications for Organic Solar Cells
Authors: Chuangchote Surawut , Fujita Michiyasu , Sagawa Takashi , Yoshikawa Susumu
Published: April 2011

Poly(3-hexylthiophene) (P3HT) nanofibers were fabricated with an association of poly(vinyl pyrrolidone) (PVP) by electrospinning. A mixture of P3HT/PVP in a mixed solvent of chlorobenzene and methanol was electrospun to form composite fibers with 60 nm - 2 μm in diameter, followed by getting rid of PVP by selective extraction. After extraction, pure P3HT nanofibers were obtained as a spindle-like structure with wrinkled surface. The nanofibers obtained exhibit specific features of strong interchain contribution as investigated by UV-vis, fluorescence spectroscopic, X-ray diffraction (XRD), and photo-electron investigations. Bulk heterojunction P3HT:PCBM nanofibers with ~200 nm in diameters were also successfully fabricated by using the same technique. The preliminary results from the study of P3HT:PCBM nanofiber-based photovoltaic cells with conversion efficiency over 0.2% could be achieved.
Anisotropic Conducting Film (ACF) of Ag Nanoparticles as Transfer Polymer and Electrical Interface for Silicon Micro- and Nano- Pillars
Authors: Ombaba Matthew , Logeeswaran V. J , Islam M. Saif
Published: April 2011

We report a novel application of Anisotropic Conductive Films (ACFs) technology to provide electrical contact and mechanical anchor between fracture transfer-printed (1-D) single crystal semiconductor micro- and nanopillars and a bottom metal. This fracture-transfer method enables highly crystalline micro- and nanopillars of different materials with diverse bandgaps and physical properties to be fabricated on appropriate mother substrates and transferred to form multilayered 3D stacks for multifunctional devices. The proposed protocol incorporates silver (Ag) nanoparticles into thermoplastic polymers exploitable in transfer-printed semiconductor devices and circuits with low contact resistance that is compatible with current IC processing methods. The vertical micropillars arrays are then embossed onto the polymer at its rubbery state by applying a vertical force leading to particle trapping between the bottom electrode and the micropillars. The polymer is then hardened while retaining the applied vertical force. By applying a lateral force on the mother substrate, the firmly cemented pillars are fractured off thereby allowing the mother substrate to be reused.
Plasmon Spectra at Wurtzite Aluminum Gallium Nitride / Silicon Carbide Heterojunctions
Authors: Praharaj Choudhury Jayant
Published: April 2011

We present theoretical calculations for electron plasmon spectra at wurtzite Aluminum Gallium Nitride/ Silicon Carbide heterojunctions. Spontaneous and piezoelectric polarizations in wurtzite semiconductors give rise to polarization discontinuities at interfaces and to bound interface sheet charges. These charges are of the order of 1013 electrons per cm2 and give rise to two dimensional electron or hole gases near heterojunctions. Electron-electron interactions in the two-dimensional electron gases give rise to collective plasmon excitations. We calculate the dielectric function in these electron gases under the well-known and widely studied random phase approximation. Our calculations are relevant to the determination of the plasmon spectra at wurtzite Aluminum Gallium Nitride / Silicon Carbide heterojunctions and are of potential interest for determining the limits of mobility in two-dimensional electron gases. They are also of interest for terahertz electronics applications.
Ion Transport and Storage in Ionic Polymer Bending Actuators
Authors: Lin Jun-Hong , Liu Yang , Hatipoglu Gokhan , Zhang Qiming
Published: April 2011

The actuation of ionic polymer actuators is mainly caused by the ion transport and excess ions storage in the membrane and electrodes. To quantify the charge transport behavior, a time domain method based on Poisson-Nernst-Planck equations was applied. The time domain transient current in response to a step voltage can provide insights on the charge transport and storage behaviors in the membranes. In this study, we investigate the charge transport behavior of Aquivion ionomer with different uptakes of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). A critical uptake and voltage independent of charge transport behavior were observed. The results also show that bending actuations of the Aquivion membrane with 40wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chain ionomer possesses a better electromechanical coupling between the excess ions and the membrane backbones, while not affect the actuation speed.
Thermo-switchable Polymer Dielectrics
Authors: Johnson Ross S. , Kholwadwala Fenil M. , Dirk Shawn M.
Published: April 2011

We are interested in utilizing the thermo-switchable properties of precursor poly(p-phenylene vinylene) (PPV) polymers to develop capacitor dielectrics that will fail at specific temperatures due to the material irreversibly switching from an insulator to a conducting polymer. By utilizing different leaving groups on the polymer main chain, the temperature at which the polymer transforms into a conductor can be varied over a range of temperatures. Electrical characterization of thin-film capacitors prepared from several precursor PPV polymers indicates that these materials have good dielectric properties until they reach elevated temperatures, at which point conjugation of the polymer backbone effectively disables the device. Here, we present the synthesis, dielectric processing, and electrical characterization of a new thermo-switchable polymer dielectric.
Modified Polyaniline Nanofibres for Ascorbic Acid Detection
Authors: Florea Larisa , Lahiff Emer , Diamond Dermot
Published: April 2011

Polyaniline nanofibres (PAni) can be surface modified to improve electroactivity over a broader pH range. The technique we describe here can be used to attach carboxylic acid terminated substituents. Modified nanofibres maintain their high surface area, and ability to switch between different redox states. These properties make the material suitable for sensing applications. Unlike unmodified PAni, the functionalised material is self-doping and hence more stable in higher pH solutions. Here we demonstrate how modified PAni fibres can be used for the detection of ascorbic acid.
Quantitative Studies of Long-term Stable, Top-down Fabricated Silicon Nanowire pH Sensor
Authors: Choi Sun , Pisano Albert P.
Published: April 2011

We report simple and effective methods to develop long-term, stable silicon nanowire-based pH sensors and systematic studies of the performance of the developed sensors. In this work, we fabricate silicon nanowire pH sensors based on top-down fabrication processes such as E-beam lithography and conventional photolithography. In order to improve the stability of the sensor performance, the sensors are coated with a passivation layer (silicon nitride) for effective electrical insulation and ion-blocking. The stability, the pH sensitivity, and the repeatability of the sensor response are critically analyzed with regard to the physics of sensing interface between sample liquid and the sensing surface. The studies verify that the sensor with a passivation layer over critical thickness show long-term, stable sensor response without long-term drift. The studies also show the detection of pH level with silicon nanowire sensors is repeatable only after proper rinsing of sensor surfaces and there exists trade-off between the stability and the pH sensitivity of sensor response.
Effect of Non-equilibrium Pulsed Ejection of Si Species into Background Gas on the Formation of Si Nanocrystallite and Nanocrystal-film
Authors: Umezu Ikurou , Okubo Shunto , Sugimura Akira
Published: April 2011

The Si nanocrystal-films are prepared by pulsed laser ablation of Si target in a mixture of helium and hydrogen gas. The total gas pressure and hydrogen partial gas pressure were varied to control structure of nanocrystal-film. The surface of Si nanocrystallite was hydrogenated and degree of hydrogenation increased with increasing hydrogen partial gas pressure. The aggregate structure of nanocrystal-film depended on both the total gas pressure and the hydrogen partial gas pressure. The former and the latter alter spatial confinement of Si species during deposition and the surface hydrogenation of individual nanocrystal, respectively. Spatial confinement increases probability of collision between nanocrystals in the plume. While, surface hydrogenation prevents coalescence of nanocrystals. The individual or aggregated nanocrystals formed in the plume reach the substrate and the nanocrystal-film is deposited on the substrate. The non-equilibrium growth processes during pulsed laser ablation are essential for the formation of the surface structure and the subsequent nanocrystal-film growth. Our results indicate that the structure of nanocrystal-film depends on the probabilities of collision and coalescence between nanocrystals in the plume. These probabilities can be varied by controlling the total gas pressure and the hydrogen partial gas pressure.
Mesoscale Simulation of Morphology in Hydrated Perfluorosulfonic Acid Membranes
Authors: Wescott James T. , Qi Yue , Subramanian Lalitha , Capehart T. Weston
Published: April 2011

Current fuel cell proton exchange membranes (PEM) rely on a random network of conducting hydrophilic domains to transport protons across the membrane. Despite extensive investigation, details of the structure of the hydrophilic domains in these membranes remain unresolved. In this study a dynamic self-consistent mean field theory has been applied to obtain the morphologies of hydrated Perfluorosulfonic Acid (PFSA) (equivalent weight of 1100) as a model for Nafion® at several water contents. A coarse-grained mesoscale model was developed by dividing the system into three components: backbone, side chain, and water. The interaction parameters for this model were generated using classical molecular dynamics. The simulated morphology shows phase separated micelles filled with water, surrounded by side chains containing sulfonic groups, and embedded in the fluorocarbon matrix. For λ<6 (λ gives the ratio of water molecules to sulfonic groups), the isolated domains obtained from simulation are nearly spherical with a domain size smaller than that fitted to experimental SANS data. For λ>8; the domains deform into elliptical and barbell shapes as they merge. The simulated morphology, hydrophilic domain size and shape are generally consistent with some experimental observations.
Application of Carbon Nanotube/Polymer Composites as Electrode for Polyelectrolyte Membrane Fuel Cells
Authors: Prehn Kirsten , Nunes Suzana Pereira , Schulte Karl
Published: April 2011

Carbon nanotubes (CNTs) possess remarkable mechanical and physical characteristics due to their unique structure. The high electrical conductivity of CNTs in combination with their structural and chemical properties make this material attractive for improvement of the performance of the electrodes in electrochemical devices, such as polyelectrolyte-membrane fuel cells. The requirements in particular for this application are manifold. Since the electrode is the reaction layer in a fuel cell, the electrolyte, being proton conductive, has to be combined with catalytic activity and electron conductivity, as well as chemical stability against the reactants. Employed as an electrode, CNTs offer feasibilities to enhance the efficiency of fuel cells due to an improved contact between electrolyte-membrane, electrode and catalyst. An other promising capacity is the large specific surface area of CNTs on which catalyst particles can be distributed in small clusters. This provides an increase of the catalyst efficiency on account of a higher reactive surface area which enables a reduction of the amount of catalyst required. In combination with a good electron conductivity, a CNT based electrode is a potential alternative fuel cell electrode. The presented work focuses on a membrane assembly, consisting of CNTs as electrode and sulfonated polyether ether ketone (SPEEK), which is used as polyelectrolyte in direct methanol fuel cells (DMFCs) and provides good proton conductivity. Nanocomposites were produced by a modified drop casting technique, leading to the formation of an asymmetric structure. Due to the process, the compounded membranes provided a single-sided electron conductivity on account of the CNTs. By using different 3D-structured CNT-carpets, varying in thickness, density and setup, the properties of the electrode membrane could be adjusted for its special application. In consideration of the insertion of platinum and ruthenium particles as catalyst in nano-sized clusters on the CNTs, carpets were modified and grown in a CVD-process at the TUHH. The evaluation of the assemblies comprised SEM-pictures in order to analyse the 3D-nano-structure, measurements of the surface conductivity as well as tests in a fuel cell.
Microstructural Control by a Rolling-Annealing Technique and Hydrogen Permeability in the Nb-Ti-Ni alloys
Authors: Tokui Sho , Ishikawa Kazuhiro , Aoki Kiyoshi
Published: April 2011

Cold rolling reduction, microstructural changes induced by cold rolling and subsequent heat treatment, hydrogen permeability (Φ) of Nb-Ti-Ni duplex phase alloys have been investigated using a rolling machine, a scanning electron microscope (SEM), an X-ray diffractometer (XRD) and a gas flow technique. The Nb-Ti-Ni alloys on the line connecting the TiNi compound and the Nb90Ti10solid solution alloy show higher rolling reduction of 70 % or more at room temperature. The value of Φ for the Nb40Ti30Ni30alloy, which is higher than that of pure Pd at 673K, decreases with increasing rolling reduction and attains to one third of that of the original one by the 50 % rolling reduction. The eutectic microstructure consisting of {TiNi+(Nb, Ti)} phases disappears and is replaced by the (Nb, Ti) phase embedded in the TiNi matrix by heat treatment 1073 K or more and for 605ks in a vacuum. However, its Φ value remains as it was by annealing at 1273 K or less, while it increases with increasing annealing periods at 1373 K or more and recovers to the original value after annealing for 605ks. These experimental results indicate that rolling and annealing techniques are the useful method for the preparation of a hydrogen permeable Nb-Ti-Ni alloy membrane.
Thermoelectric properties of epitaxial and topotaxial NaxCoO2 thin films
Authors: Venimadhav Adyam , Ma Z , Li Qi , Soukiassian A , Xi X. X. , Schlom D. G. , Arroyave R. , Liu Z. K. , Lee Minhyea , Ong N. P.
Published: April 2011

We report structural, electrical, and thermopower properties of epitaxial and topotaxial NaxCoO2 thin films on (0001) sapphire substrate. Topotaxial NaxCoO2 films were prepared by converting an epitaxial Co3O4 film to NaxCoO2 by annealing in Na vapor and epitaxial NaxCoO2 films were obtained by pulsed laser deposition. All the films are c-axis oriented. For topotaxial films, annealing in different Na vapor pressures resulted in films with different Na concentrations, which showed distinct transport properties. For directly deposited epitaxial films by pulsed laser deposition, deposition parameters are found to control the Na concentration and hence the film properties. The largest thermoelectric power of the samples made by different methods is found to be similar in the range of 70-100 μV/K at room temperature
Preparation of [(Bi2Te3)x(HfTe2)]y Superlattices
Authors: Schmid Benjamin Allen , Harris Fred R , Johnson David C
Published: April 2011

The synthesis of a number of (Bi2Te3)x(HfTe2)y superlattices was accomplished using the modulated elemental reactants (MER) method. The samples were characterized using X-ray reflectivity and X-ray diffraction in the as deposited (amorphous) state and as a function of annealing temperature and time.
Preparation of (TiTe2)x(Sb2Te3)y(TiTe2)3(Bi2Te3)z Superlattices using the Modulated Elemental Reactants (MER) Technique
Authors: Mortensen Clay , Matelich Ben , Schmid Benjamin , Rostek Raimar , Johnson David C.
Published: April 2011

Difficulty in preparing (Bi2Te3)x(Sb2Te3)y superlattices due to interdiffusion of Sb and Bi led to the study of interduffusion barriers. TiTe2 has been explored as an interdiffusion barrier to minimize the interdiffusion of Sb and Bi, as TiTe2 is not soluble in either Bi2Te3 or Sb2Te3. Preparation of (TiTe2)3(Sb2Te3)y(TiTe2)3(Bi2Te3)z superlattices has been achieved with varying x, y and z. The formation of the superlattices was studied as a function of annealing temperature and time. TOF-SIMS depth profiles were used to study the extent of interdiffusion in the samples. Unit cell control was achieved allowing for the preparation of an array of superlattices with varying periods with very good reproducibility.
Ab initiostudies of electronic structure of defects on the Te sites in PbTe
Authors: Ahmad Salameh , Mahanti S. D. , Kanatzidis M. G.
Published: April 2011

Ab initioelectronic structure calculations have been carried out to understand the nature of anionic defect states in PbTe. We find that Te vacancies strongly perturb the electronic density of states (DOS) near the band gap region. New states of predominantly Pb p character appear in the band gap. Iodine is an ideal substitutional defect and a donor. Sulpher and Selenium do not affect the states near the conduction band minimum but suppress the DOS near the valence band maximum. These results have important implications on the thermoelectric properties of PbTe and PbTexM1−x(M=S, Se) ternary systems.
Thermoelectric Modeling of Si-Si1−xGex Ordered Nanowire Composites
Authors: Tang Ming Y. , Dresselhaus Mildred S. , Yang Ronggui , Chen Gang
Published: April 2011

Thermoelectrics have always been attractive for power generation and cooling because of power reliability and environmentally friendly issues. However, this concept remains non-competitive due to the limitation in the efficiency of available thermoelectric materials and device designs [1]. In the 1990s, Hicks and Dresselhaus predicted the possibility of a dramatic enhancement in thermoelectric performance based on the special behavior of low dimensional materials [2, 3]. This enhancement is in part due to the increase in quantum confinement effects, the increase in electronic density of states at specified energies, and the increase in the phonon interface scattering for low dimensional structures.

Nanowires and core-shell nanowires can be considered to be model systems to illustrate representative behavior in low dimensional thermoelectric materials. It is expected that a system made out of nanowires or core-shell nanowires would have a higher thermoelectric performance than its bulk counterpart due to an increase in the number of interfaces. The interfaces that are introduced must be such that phonons are scattered more strongly than are electrons. Theoretical studies have been carried out to better understand the transport properties of Si-Si1−xGex ordered nanowire composites. The composite is modeled as having Si wires embedded in a Si1−xGex host matrix. Thus, core-shell Si/Si1−xGex nanowires can be considered as a building block of the composite. The effect of the wire diameter and the shell alloy composition on ZT is presented.