bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecularly Imprinted Polymers (MIPs) Against Uracils: Functional Monomer Design, Monomer-Template Interactions In Solution And MIP Performance In Chromatography
Authors: Hall Andrew J. , Manesiotis Panagiotis , Mossing Jakob T. , Sellergren Börje 
Published: April 2017

AbstractThe interaction of N1-substituted uracils (cyclohexyl (1) and benzyl (2)) with three polymerisable recognition elements, the novel monomers 9-(3/4-vinylbenzyl)adenine (3) and 2,6-diamino-9-(3/4-vinylbenzyl)purine (4) and the previously synthesised monomer 2,6-bis(acrylamido)pyridine (5), has been studied via1H NMR in deuterio-chloroform solution. MIPs against (2) have been prepared using each of the monomers and tested in the chromatographic mode. The effect of the number and type of hydrogen bonds formed between the templates and the functional monomers is reflected in the values of the apparent association constants obtained from the solution study and by the performance of the subsequently prepared MIPs in the chromatographic mode.
Sensor Materials - Detecting Molecules, Mixtures and Microorganisms -
Authors: Dickert Franz L. , Hayden Oliver , Lieberzeit Peter A. , Palfinger Christian 
Published: April 2017

AbstractSensor materials based on molecularly imprinted organic and inorganic polymers were designed and characterized according to their selectivity and sensitivity using mass-sensitive quartz crystal microbalances (QCMs). Cavities of differing shapes and sizes were created in both organic and inorganic polymers, able to selectively re-include the template species. Imprinting was performed both on the molecular and the micrometer scale. The chemical and biomimetic sensors developed allow the detection of various analytes, such as VOCs in ambient conditions, complex mixtures (automotive engine oils) and microorganisms. Thus, the extraordinary flexibility of templating methods is proved as the most versatile platform technology for advanced sensor materials.
On Route to the Chiral Imprinting of Bulk Silica
Authors: Ini Santiago , Defreese Jessica L. , Parra-Vasquez Nicholas , Katz Alexander 
Published: April 2017

AbstractShape-selective pores have been synthesized in bulk silica via imprinting. The synthetic approach relies on a sol-gel process to immobilize the imprint within a hybrid organic/inorganic material. Cleavage of the carbamate linkage from this material generates a primary amine within a microporous binding site. Characterization studies, including potentiometric titration and solid-state nuclear magnetic resonance spectroscopy, indicate that most imprinted amine sites are accessible during binding with small molecule probes. However, larger probes are unable to adsorb to the same material, indicating significant shape-selectivity in binding. Additionally, an investigation of framework pore size effects in a catalytic system shows that shape-selectivity can be solely a result of the imprinted active site and not the framework structure.
Studies on the Process of Formation, Nature and Stability of Binding Sites in Molecularly Imprinted Polymers
Authors: Lanza F. , Rüther M. , Hall A.J. , Dauwe C. , Sellergren B. 
Published: April 2017

AbstractIn Molecular Imprinting the nature of the templated binding sites and the mechanism of their formation are still poorly understood. For this reason our groups are carrying out fundamental studies concerning known imprinting protocols, with the primary aim of shedding light on the role of the template in the different steps of the polymerisation, from the formation of primary chains to the build-up of the porous structure. In this paper we report our initial results concerning copolymers of methacrylic acid (MAA) and ethyleneglycol dimethacrylate (EDMA) and their formation in presence or absence of the templates 9-ethyladenine, ametryn or terbutylazine. Monitoring the monomer disappearance by 1H-NMR showed that the presence of templates such as 9-ethyladenine significantly retarded the polymerisation but otherwise had minor influence on the relative reactivity of the monomers. The latter appeared in most cases to be stoichiometrically incorporated into the polymer. The signals arising from the template experienced little or no shift in the early stage of the polymerisation, although pronounced broadening was observed. By delaying the addition of the template, it was observed that binding sites with high selectivity could be induced more than one hour after the gel point of the system had been passed. Finally, the results of post-polymerisation curing on the dry and swollen state porosities and the recognition properties of terbutylazine imprinted polymers are reported. This treatment when performed at temperatures between 100-120°C, slightly enhanced the selectivity of the polymers, whereas at higher temperatures the polymers lost their molecular recognition properties. Swollen state porosity derived from inverse size exclusion chromatography (ISEC) revealed an interesting sharpening of the pore size distribution for the imprinted compared to the non-imprinted polymers.
Signal Generation from Switchable Polydiacetylene Fluorescence
Authors: Reppy Mary A. 
Published: April 2017

AbstractChemical and biological sensors require a material component to act as a transducer from the molecular level event of interest to a discernable output measurable in the macroscopic world. One such material is polydiacetylene (PDA), a conjugated polymer that can switch from harnessed to provide signal generation for bio-sensors and assays as a more sensitive alternative to the previously reported monitoring of PDA colorimetric shifts. While providing a more sensitive transduction mechanism the fluorescence behavior of PDA is also more complicated than the absorbance, in particular the emission profile of PDA in liposomes is strongly affected by the extent of polymerization. Incorporating small molecule fluorophores into the PDA materials further increases the overall emission of fluorescent PDA materials. The fluorophores accept energy from the excited state of the polymer and fluoresce, leading to both an overall increase in the quantum yield of the system and an increase in the Stokes shift. Basic photophysical properties of fatty acid PDA liposomes and a model assay for phospholipase A2 are presented. The model assay results show that the fluorescence response is greater than the colorimetric, and is further enhanced by addition of fluorophores.
Modification of Deposition Process of Piezoelectric Polycrystalline Film by Hydrothermal Method -Improvement of the Deposition Process by Pre-Treatment Using Hydrogen Peroxide
Authors: Endo Akito , Kawashima Norimichi , Takeuchi Shinichi , Ishikawa Mutsuo , Kurosawa Minoru 
Published: April 2017

AbstractWe have studied on hydro-thermally synthesis of Pb(Ti, Zr)O3(PZT)piezoelectric polycrystalline thick film on titanium (Ti) substrate. The purpose of this study is resolving the problems for application of PZT hydrothermal polycrystalline thick film to the ultra miniature high frequency medical ultrasound array probe. The problems were the existence of pinholes in the deposited PZT film, the rough surface of that, low dielectric breakdown electric field etc. The surface of Ti substrate was pretreated to have hydrophilic property by using high reactivity of hydrogen peroxide for resolving the problems in this study. As results, hydrophilic property on the surface of Ti substrate was improved. Surface of PZT hydrothermal polycrystalline thick film without pinholes and smooth surface of that were obtained. Furthermore, the material properties like density, Young's modulus and piezoelectric constant d31 were increased by the pretreatment of Ti substrate. Consequently, dielectric breakdown electric field of PZT hydrothermal polycrystalline film was improved.
Thin Film Silicon Microbridges for DNA Detection
Authors: Adrega T. , Gaspar J. , Fixe F. , Chu V. , Prazeres D.M.F. , Conde J.P. 
Published: April 2017

AbstractThin-film MEMS molecular sensors are fabricated at temperatures below 110°C on glass substrates. The microelectromechanical structure consists of a surface micromachined bilayer bridge of phosphorous-doped hydrogenated amorphous silicon and aluminum with a patterned SiO2 layer on the top. Specific binding of DNA to functionalized SiO2 on the bridge is confirmed using fluorescence microscopy. Microbridges are electrostatically actuated and the resonance frequency measurements are performed in vacuum in the initial state after fabrication, after the chemical functionalization of the SiO2surface and after DNA immobilization. The sensor is able to detect the functionalization molecular layer, the cross-linker molecular layer, and the DNA molecules attached to the surface through a shift in its resonance frequency. The binding of molecules to the surface results in a shift of the resonance frequency due to contributions from surface stresses and mass loading.
Fabrication and Electromechanical Properties of Conductive Polymer Microbridge Actuators
Authors: Zhang Guandong , Gaspar Joao , Chu Virginia , Conde Joao Pedro 
Published: April 2017

AbstractThis paper reports on the fabrication of novel all-polymer microbridge electrostatic actuators based on conductive polymers and using surface micromachining on glass substrates. The electromechanical properties of the microbridges are studied using electrostatic actuation and optical and electrical detection. The pull-in phenomena and a dependence of the bridge deflection with the square of the applied voltage are observed. Compared to the silicon-based microbridges, the polymer structures present higher deflection amplitude for the same applied electrical force. The resonance frequency of the polymer bridges occurs in the MHz range and with quality factors of the order of 100 when measured in vacuum. The mechanical properties of the polymer device are affected by the residual stresses.
Low-cost and Chemical Resistant Microfluidic Devices Based on Thermoplastic Elastomers for a Novel Biosensor System
Authors: Stoyanov I. , Tewes M. , Glass S. , Koch M. , Löhndorf M. 
Published: April 2017

AbstractLow-cost and chemical resistant microfluidic devices based on thermoplastic elastomers have been fabricated by hot embossing technology. Commercial available thermoplastic elastomer foils based on polyurethane (PU) in a thickness range of 100-600 μm have been used. Prior to the fabrication of the microfluidic devices the chemical resistance of the material against a wide range of standard biological buffer solutions and solvents had been analysed. We created systems of channels, reservoirs and holes for the connections to external capillaries by double-sided hot embossing with an alignment accuracy of +/- 3 micrometer. Closed channel structures were produced by an additional chemical bonding process of the embossed devices with another thermoplastic elastomer foil. The total volume of the fluidic cell was 2 μl/sensor for the use with SAW (surface-acoustic wave) sensor chip and about 0.2 μ/sensor for the impedance sensors. A novel multi-chamber fluidic device was successfully tested for in-situ immobilization of thrombin antibodies and Bovin Serum Albumin (BSA) on different sensor elements of the same sensor chip.
Embedded Piezoresistive Microcantilever Sensors: Materials for Sensing Chemical and Biological Analytes
Authors: Porter Timothy L. , Delinger William , Gunter Robert L. 
Published: April 2017

AbstractWe have used embedded piezoresistive microcantilever (EPM) sensors in the detection of volatile organic compounds, industrial chemicals, and biological molecules. The EPM design incorporates a tiny piezoresistive microcantilever embedded or partially embedded into a material sensing layer. The sensing layer material is chosen so as to react to the desired analyte(s), and undergo a minute volumetric or vertical shift in dimension. In the present paper, we present results on the sensing of various VOC's, vaccinia virus in solution, carbon tetrachloride in vapor, and osmolality in human subjects.
A Systematic Study of the Formation of Nano-Tips on Silicon Thin Films by Excimer Laser Irradiation
Authors: Georgiev D.G. , Baird R.J. , Avrutsky I. , Auner G. , Newaz G. , Tokranova N. 
Published: April 2017

AbstractRecently, we reported conditions for controllable, direct laser fabrication of sharp conical tips with heights of about one micrometer and apical radii of curvature of several tens of nanometers. An individual cone is formed when a single-crystal silicon film on an insulator substrate is irradiated in air environment with a single pulse from a KrF excimer laser, homogenized and shaped to a circular spot several microns in diameter. In this work, we present a study of the formation of such tips as a function of the laser fluence, the film thickness, and the diameter of the irradiated spot. Atomic force microscopy and scanning electron microscopy were used to study the topography of the structures. A simple mechanism of formation based on movement of melted material is proposed. We have also studied structures (nano-ridges) that resulted from irradiation with narrow lines (width of several microns) instead of circular spots.
In-Situ Pretreatment Approach for Surface Deterioration Alleviation Amidst Thermal Desorption of GaAs(100)
Authors: Pun A.F. , Wang X. , Meeks J.B. , Durbin S.M , Zheng J.P. 
Published: April 2017

AbstractWithin this study, a novel in-situ pretreatment is proposed theoretically and demonstrated experimentally, in which the formation of surface pits is subsequently stifled during thermal desorption. The proposed method involves fueling the well reviewed chemical oxide reduction reaction with a segregated source of material other than that ordinarily utilized in pit formation. The proposed method is implementable in virtually all deposition systems subject to the constraints of providing material deposition, substrate heating, and the creation of non-oxidizing environments either via vacuum or inert atmo sphere.
A Wide Band Gap Boron-doped Microcrystalline Silicon Film Obtained with VHF Glow Discharge Method
Authors: feng Zhu , ying Zhao , changcun Wei , xiaodan Zhang , yantao Gao , jian Sun , xinhua Geng 
Published: April 2017

AbstractA wide bandgap microcrystalline silicon film for the window layer of microcrystalline silicon thin film solar cells was obtained with very high frequency (VHF) glow discharge technology. The material was deposited on corning 7059 substrate at about 170 When H2/SiH4was more than 100, Raman spectra showed that this material was highly crystallized, and no peak correlation with amorphous silicon was observed. This material showed strong n type before any intentional doping. We considered that the unintentional doping of oxygen and unpurified gases. The doping performance of this material was investigated by introducing B2H6into the reacting gas. As increasing the rate of B2H6/SiH4from zero to 0.5%, the conductivity changed from 10-1S.cm-1(n type) to 10-8S.cm-1dramatically and than backed to 10-1S.cm-1(p type), which indicated that this material had excellent doping ability. Raman spectra also showed that the microstructure of these materials did not change obviously in this doping range. We gained the p-uc-Si:H film with thickness less than 30nm, and the conductivity was more than 10-2S.cm-1, and crystalline volume fraction no less than 40%, the Egoptcould be wider than 2.10eV. Using this p window layer in microcrystalline silicon solar cells with no ZnO rear reflection, the conversion efficiency was 8.30% (Voc=0.531V, Jsc=24.66mA/cm2, FF=63.41% ).
Stabilized Pd-alloy/AlN/Si Hydrogen Sensors
Authors: Zhang Linfeng , Al-Homoudi Ibrahim , Rahman Md H. , McCullen Erik F. , Rimai Lajos , Baird Ronald J. , Naik Ratna , Newaz Golam , Auner Gregory W. , Ng K.Y. Simon 
Published: April 2017

AbstractIn order to extend the dynamic range of a hydrogen sensor with a metal-insulator-semiconductor (MIS) type structure, Pd-Cr and Pd-Ni alloy gated samples were studied. The PdCr gated sample shows quite stable and reproducible response, and could measure hydrogen concentrations from 100 to 50, 000 ppm. While the Pd-Ni gated sample shows turn-on/off response drift, this drift is probably due to the presence of oxygen on the surface of the insulator and the formation of metal hydride. Furthermore, the effect of oxygen on the sensors response was investigated; oxygen may deplete protons from the metal/insulator interface and could reduce the sensor's response.
Growth, Characterization and Processing of VO2 Thin Films for Micro-switching Devices
Authors: Soltani Mohamed , Stafford Luc , Chaker Mohamed , Margot Joëlle 
Published: April 2017

AbstractSingle-phase vanadium-dioxide (VO2) thin films have been deposited on various substrates by means of a reactive pulsed-laser-deposition technique. While the preferred orientation is (011) monoclinic for the films deposited on silicon substrates and (020) monoclinic for those deposited on sapphire substrates, the thermochromic properties of the VO2 layers is found to be fairly independent of the substrate type. It is further shown that W doping and Ti-W co-doping significantly improve the thermochromic properties. Following growth, VO2 layers were used in the context of the development of micro-switching devices. For this purpose, patterning of the VO2 layers was investigated using a high-density argon magnetoplasma. Highly anisotropic features have been produced with a high etch rate and a good selectivity over resist. The etch rate for VO2/Al2O3 samples is found to be higher than that for VO2/Si samples, which is due to the higher number of surface dangling bonds in the (020) phase as compared to the (011) phase.
Effects of Substrate Materials on the Electrical Behavior of Pd/AlN/Semiconductor Based Hydrogen Sensors
Authors: Rahman Md. H. , Zhang L. , Rimai L. , Baird R.J. , Naik R. , Ng K.Y.S. , Auner G. , Newaz G. 
Published: April 2017

AbstractC-plane textured wurtzite AlN films deposited on both, 3C and 6H SiC as well as Si, have been employed in Pd/AlN/Semiconductor diode Hydrogen sensor structures. The SiC based devices behave as rectifiers and do not show the bias dependent capacitance expected for an MIS structure when reverse biased. The Si based devices, albeit exhibiting rectifying characteristics do show the expected dependence of capacitance on reverse bias, with typical depletion and inversion regions. The SiC based devices show the sensor response as change in bias voltage at constant forward current but the Si based device showed no response in this mode of operation albeit it did respond well in terms of the Hydrogen induces shift of the depletion capacitance vs. bias characteristic. As the AlN itself has the same structure in all cases, the differences in both, electrical characteristics and sensing response mechanism are related to differences in the AlN/Substrate heterojunction resulting from differences in the electronic band structure of the substrates.
Ultra-Fine ZnO Nanobelts and their Photoluminescence Emission
Authors: Khan Aurangzeb , Kordesch Martin E 
Published: April 2017

AbstractUltra-Fine ZnO nanobelts are grown via thermal evaporation and condensation method without the use of any catalyst on the substrates. These nanobelts have an average width of about 5.8 nm. Photoluminescence spectra reveal that there is a blue shift in the near band edge ultra violet emission from 381 nm to 367 nm equal to 124 meV. These ultra-fine nanobelts have been studied for size induced optical and electrical properties.
Quantum Sizing of Power Electronics: A Trend Towards Miniaturiation of Power Electronic Systems and Equipments
Authors: Chakraborty Arindam , Emadi Ali 
Published: April 2017

AbstractHuman ability to manipulate atoms and molecules on quantum basis has generated a new dimension of physical structures for molecular scale transistors and devices. We will discuss about nanodimensional single electron transistor. This molecular device works as a switching element by controlling the electron tunneling for amplifying the current. The basic structure consists of two tunnel junctions isolated by a common insulator of nanodimensional length.One broader aspect of nano power electronics is that, it has got significant role in nanodimensional device regime as tunneling diodes. They have got inherently fast tunneling rate, which makes them highly suitable for high-speed operation. A special type of tunneling diode is an interband tunneling diode (ITD), which is actually, a p-n diode. The V-I characteristics of such diodes are dependent upon the tunneling barrier and tunneling process itself. Another special feature of these diodes is their negative-differential-resistance characteristics. This special characteristic of such diodes makes them very useful in switching digital circuits.
Critical Process Issues in the Fabrication of a Lateral, Self-cleaning, MEMS Switch
Authors: Shi Yong , Kim Sang-Gook 
Published: April 2017

AbstractA lateral contact MEMS switch was developed to address the needs for long life cycle, low contact resistance and low cost switches. The device is unique in its self-cleaning of particles, self-alignment of contact surfaces and the mechanical anchoring of the contact metal into the switch structures. The major issue for the lateral contact device fabrication is the creation of the vertical Au sidewall. Existing physical and chemical vapor deposition methods are found not satisfactory. The final Au sidewalls for electric contact are formed by electroplating in pre-patterned photoresist mold. SEM pictures show that the designed undulated contact surfaces are created successfully, and the surface of the electroplated Au is much smoother and denser than that by e-beam evaporation. The long lifecycle test shows that the contact resistance has been maintained below 0.1 Ω over 1010 cycles. The test results of the fabricated switch have proved the self-cleaning concept and opened the possibility of direct contact MEMS switch for high power and low cost RF applications.
The Performance of the Gate Electrode Using Co Thin Films Selectively Deposited on SAMs Patterns for a-Si TFT
Authors: Yang H.J. , Lee J.G. , Cho B. S. , Lee J. H. , Jeong C. O. , Chung K. H. 
Published: April 2017

AbstractSelective deposition of Co thin films has been developed to produce Co pattern for TFT gate electrode on glass. We have been carried out by the selective growth of Co films with combination of micro-contact printing and metal organic chemical vapor deposition (MOCVD) at low temperature below 100°C. In the first step octadecyltrichlorosilane(OTS) layer with polydimethylsiloxane(PDMS) stamps was pre-patterned on glass. The patterned OTS area created a hydrophobic surface on glass which can prohibit nucleation and growth of Co films. In the second step a MOCVD Co selective deposition examined the difference of incubation time between OTS coated glass and pure glass.We optimized Co selective deposition through working pressure, deposition temperature, and gas flow rate ratio. Root mean square (rms) of Co films deposited on glass is 2nm enough to use gate electrode.OTS pattern was decomposed by UV treatment in the range of 280 and 350nm and then trilayer(n+Si/a-Si/SiNx) was continuously created on the sample which was selectively organized Co gate electrode on glass. We fabricated thin film transistor (TFT) of inverse staggered type using selectively deposited Co gate pattern. Reflectance was used to evaluate incubation time for Co deposition time and AFM was employed to confirm selectivity of Co thin film. The subthreshold slope and on/off current ratio was 0.88 V/decade and 6x106, respectively. The electron field-effect mobility at saturation was 0.35 cm2/Vs for Vd = 9V.