The Molecularly Imprinted Polymers. Influence of Monomers on The Properties of Polymers - A Review

The synthesis of MIPs for two types of templates (herbicides, and flavonoids) and their application in analytical chemistry are discussed. Particular attention has been paid the issue of bonding the template and selection of appropriate monomer in different types of compounds. This short review aims at presenting the molecular imprinting technology (MIT) which is considered as an attractive method to produce impressive receptors for application in analytical chemistry. The challenge of designing and synthesizing a molecularly imprinted polymer (MIP) can be a daunting prospect to the uninitiated practitioner, simply because of the number of experimental variables involved, e.g. the nature and levels of template, functional monomers, cross-linkers, solvents, initiators and even the method of initiation and the duration of polymerization. Indubitably, the most important place of the polymer is its quotheartquot or the cavity corresponding to the template and the waynbs

Charge transfer and trapping as origin of a double dip in the transfer characteristics of graphene based field-effect transistors

We discuss the origin of an additional dip other than the charge neutrality point observed in transfer characteristics of graphene-based field-effect transistors. The double-dip is proved to arise from charge transfer between graphene and metal electrodes, while charge storage at the graphene/SiO2 interface enhances it. Considering different Fermi energy from the neutrality point along the channel and partial charge pinning at the contacts, we propose a model which explains all features in gate voltage loops.Comment: 14 pages, 5 figure

Graphene Grown on Ge(001) from Atomic Source

Among the many anticipated applications of graphene, some - such as transistors for Si microelectronics - would greatly benefit from the possibility to deposit graphene directly on a semiconductor grown on a Si wafer. We report that Ge(001) layers on Si(001) wafers can be uniformly covered with graphene at temperatures between 800{\deg}C and the melting temperature of Ge. The graphene is closed, with sheet resistivity strongly decreasing with growth temperature, weakly decreasing with the amount of deposited C, and reaching down to 2 kOhm/sq. Activation energy of surface roughness is low (about 0.66 eV) and constant throughout the range of temperatures in which graphene is formed. Density functional theory calculations indicate that the major physical processes affecting the growth are: (1) substitution of Ge in surface dimers by C, (2) interaction between C clusters and Ge monomers, and (3) formation of chemical bonds between graphene edge and Ge(001), and that the processes 1 and 2 are surpassed by CH$_{2}$ surface diffusion when the C atoms are delivered from CH$_{4}$. The results of this study indicate that graphene can be produced directly at the active region of the transistor in a process compatible with the Si technology

Graphene field effect transistors with Niobium contacts and asymmetric transfer characteristics

We fabricate back-gated field effect transistors using Niobium electrodes on mechanically exfoliated monolayer graphene and perform electrical characterization in the pressure range from atmospheric down to 10-4 mbar. We study the effect of room temperature vacuum degassing and report asymmetric transfer characteristics with a resistance plateau in the n-branch. We show that weakly chemisorbed Nb acts as p-dopant on graphene and explain the transistor characteristics by Nb/graphene interaction with unpinned Fermi level at the interface.Comment: 10 pages, Research Pape

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

We demonstrate tunable Schottky barrier height and record photo-responsivity in a new-concept device made of a single-layer CVD graphene transferred onto a matrix of nanotips patterned on n-type Si wafer. The original layout, where nano-sized graphene/Si heterojunctions alternate to graphene areas exposed to the electric field of the Si substrate, which acts both as diode cathode and transistor gate, results in a two-terminal barristor with single-bias control of the Schottky barrier. The nanotip patterning favors light absorption, and the enhancement of the electric field at the tip apex improves photo-charge separation and enables internal gain by impact ionization. These features render the device a photodetector with responsivity (3 A/W for white LED light at 3 mW/cm2 intensity) almost an order of magnitude higher than commercial photodiodes. We extensively characterize the voltage and the temperature dependence of the device parameters and prove that the multi-junction approach does not add extra-inhomogeneity to the Schottky barrier height distribution. This work represents a significant advance in the realization of graphene/Si Schottky devices for optoelectronic applications.Comment: Research paper, 22 pages, 7 figure

Biomasa alg słodkowodnych surowcem dla przemysłu i rolnictwa

Wykorzystując doniesienia literaturowe oraz wyniki badań własnych, przedstawiono występowanie, budowę chemiczną i morfologiczną alg słodkowodnych występujących także na terenie Polski oraz zastosowanie ich biomasy jako cennego surowca dla różnych gałęzi przemysłu i rolnictwa. Z powodu braku w Polsce systemu wykorzystywania biomasy alg do celów przemysłowych i rolniczych, zagospodarowanie tych surowców powstających na dużą skalę w zbiornikach wodnych stanowi duże wyzwanie i jest istotnym elementem gospodarki zrównoważonego rozwoju.Praca sfinansowana ze środków grantu PBS 1/A1/2/2012: „Innowacyjna technologia ekstraktów glonowych – komponentów nawozów, pasz i kosmetyków” przyznanego przez Narodowe Centrum Badań i Rozwoju.92710011004Przemysł Chemiczn

Synthesis and characterization of Zr2Al3C4 thin films

Zr2Al3C4 is an inherently nanolaminated carbide where layers of ZrC alternatewith layers of Al3C2. Characterization of bulk samples has shown it has improved damage tolerance and oxidation resistance compared to its binary counterpart ZrC. Though a potential candidate for coatings applied for use in harsh environments, thin films of Zr2Al3C4 have not been reported.We have synthesized epitaxial Zr2Al3C4 thin films by pulsed cathodic arc deposition from three elemental cathodes, and have studied the effect of incident atomic flux ratio, deposition temperature, and choice of substrate on material quality. X-ray diffraction analysis showed that Zr2Al3C4 of the highest structural quality was obtained for growth on 4 H-SiC(001) substrate at 800 ^deg;C. Also, suppression of competing phases could be achieved on á-Al2O3(001) at elevated substrate temperatures. Very similar growth behavior to that of the well-known Mn+1AXn phases - Al supersaturation, binary carbide intergrowth and high sensitivity to choice of substrate - indicates a strong connection between the two families ofmaterials, despite their differences in structure and in chemistry

Current incidence, severity, and management of veno-occlusive disease/sinusoidal obstruction syndrome in adult allogeneic HSCT recipients:an EBMT Transplant Complications Working Party study

The current incidence, diagnostic policy, management, and outcome of VOD/SOS at EBMT centers were studied. All centers that had performed allogeneic HSCTs in adult patients within one defined year were invited to the study. Seventy-one centers participated with a total of 2886 allogeneic transplantations and 93 cases of VOD/SOS in 2018. The cumulative incidence of VOD/SOS at day 21 was 1.8% and at day 100 2.4%. Of 67 cases with detailed data, 52 were classical and 15 (22%) late onset (&gt;day 21). According to the EBMT criteria, 65/67 patients had at least two VOD/SOS risk factors. The severity grades were: mild 0, moderate 3, severe 29, very severe 35. Fifty-four patients were treated with defibrotide. VOD/SOS resolved in 58% of the patients, 3/3 with moderate, 22/28 with severe, and 12/33 with very severe grade (p &lt; 0.001). By day 100, 57% of the patients were alive; 3/3 with moderate, 22/29 with severe, and 13/35 with very severe VOD/SOS (p = 0.002). In conclusion, the incidence of VOD/SOS was low. Severe and very severe grades dominated. Very severe grade predicted poor outcome compared to severe grade further supporting the concept of early diagnosis and treatment to avoid a dismal outcome. [Figure not available: see fulltext.]</p