A tetrabenzotriazaporphyrin based organic thin film transistor: Comparison with a device of the phthalocyanine analogue

The characteristics of bottom-gate bottom-contact organic thin film field-effect transistors (OTFTs) with 70 nm thick films of solution processed non-peripherally octahexyl-substituted nickel tetrabenzo triazaporphyrin (6NiTBTAP) molecules as active layers on silicon substrates are experimentally studied and the results are compared with the similary configured transistors using the corresponding nickel phthalocyanine (6NiPc) compound. 6NiTBTAP transistors are found to exhibit improved performance over 6NiPc transistors in terms of greater saturation hole mobility, two orders of magnitude higher on/off ratio and lower threshold voltage. This enhanced performance of 6NiTBTAP OTFTs over 6NiPc devices is attributed to improved surface morphology and large grain size of the active 6NiTBTAP film

High-mobility solution-processed copper phthalocyanine-based organic field-effect transistors

© 2011 National Institute for Materials ScienceSolution-processed films of 1,4,8,11,15,18,22,25-octakis(hexyl) copper phthalocyanine (CuPc6) were utilized as an active semiconducting layer in the fabrication of organic field-effect transistors (OFETs) in the bottom-gate configurations using chemical vapour deposited silicon dioxide (SiO2) as gate dielectrics. The surface treatment of the gate dielectric with a self-assembled monolayer of octadecyltrichlorosilane (OTS) resulted in values of 4×10−2 cm2 V−1 s−1 and 106 for saturation mobility and on/off current ratio, respectively. This improvement was accompanied by a shift in the threshold voltage from 3V for untreated devices to −2V for OTS treated devices. The trap density at the interface between the gate dielectric and semiconductor decreased by about one order of magnitude after the surface treatment. The transistors with the OTS treated gate dielectrics were more stable over a 30-day period in air than untreated ones.Technology Strategy Board, UK (Project No: TP/6/EPH/6/S/K2536J)

On the feasibility of collaborative green data center ecosystems

The increasing awareness of the impact of the IT sector on the environment, together with economic factors, have fueled many research efforts to reduce the energy expenditure of data centers. Recent work proposes to achieve additional energy savings by exploiting, in concert with customers, service workloads and to reduce data centers’ carbon footprints by adopting demand-response mechanisms between data centers and their energy providers. In this paper, we debate about the incentives that customers and data centers can have to adopt such measures and propose a new service type and pricing scheme that is economically attractive and technically realizable. Simulation results based on real measurements confirm that our scheme can achieve additional energy savings while preserving service performance and the interests of data centers and customers.Peer ReviewedPostprint (author's final draft

A liquid crystalline copper phthalocyanine derivative for high performance organic thin film transistors

This journal is © The Royal Society of Chemistry 2012Bottom-gate, bottom-contact organic thin film transistors (OTFTs) were fabricated using solvent soluble copper 1,4,8,11,15,18,22,25-octakis(hexyl)phthalocyanine as the active semiconductor layer. The compound was deposited as 70 nm thick spin-coated films onto gold source–drain electrodes supported on octadecyltrichlorosilane treated 250 nm thick SiO2 gate insulators. The performance of the OTFTs was optimised by investigating the effects of vacuum annealing of the films at temperatures between 50 0C and 200 0C, a range that included the thermotropic mesophase of the bulk material. These effects were monitored by ultraviolet-visible absorption spectroscopy, atomic force microscopy and XRD measurements. Device performance was shown to be dependent upon the annealing temperature due to structural changes of the film. Devices heat treated at 100 0C under vacuum (≥10-7 mbar) were found to exhibit the highest field-effect mobility, 0.7 cm2 V^-1 s^-1, with an on–off current modulation ratio of~107, a reduced threshold voltage of 2.0 V and a sub-threshold swing of 1.11 V per decade.UK Technology Strategy Board (Project no: TP/6/EPH/6/S/K2536J) and UK National Measurement System (Project IRD C02 ‘‘Plastic Electronics’’, 2008–2011)

Newly Synthesised Gadolinium bis-Phthalocyanine Sandwich Complex: Ambipolar Organic Semiconductor

Time of flight (TOF) photocurrent transient studies on 5µm thick solution processed films of novel non-peripherally octa-octyl-substituted liquid crystalline gadolinium bis-1,4,8,11,15,18,22,25-octakis(octyl) phthalocyanines (8GdPc2) provide a quantitative analysis of the intrinsic ambipolar charge transport relative to mesomorphic structure of this lanthanide compound. Characteristic liquid crystalline phases of these molecules have been identified from differential scanning calorimetry supported by observation from the UV-visible absorption, showing crystal-columnar mesophase and columnar mesophase-isotropic liquid transitions at 64.2°C and 162°C, respectively. The TOF carrier mobility is found to be structure dependent and highest values of 4.73×10−6m2/Vs and 1.6×10−6m2/Vs have been estimated for hole and electron mobilities for hexagonally packed, columnar structures of the spin-coated films. These results are exploitable for development of single molecule based all organic complimentary analogue and digital circuits with tunable field effect performance

Compact modeling of organic thin film transistors with solution processed octadecyl substituted tetrabenzotriazaporphyrin as an active layer

Using 70nm thick spin-coated film of newly synthesized octadecyl substituted copper tetrabenzotriazaporphyrin (10CuTBTAP) as an active layer on a highly doped silicon (110) gate electrode substrates, output characteristics and transfer characteristics of bottom-gate bottom-contact organic thin film transistors have been measured at room temperature. A compact model for thin film transistors has been employed as a part of circuit design tool to extract device parameters such as the charge carrier mobility μ, the threshold voltage VT and the contact resistances. Parallel measurements and analysis were performed on similarly constructed devices with a copper phthalocyanine analogue (10CuPc). The results reveal that the 10CuPc layer is relatively more susceptible to trapping degradation near the gate region than a 10CuTBTAP layer, which is significant in order to achieve stability in these transistors. The application of the simple square law in the classical MOS model provides a quicker but approximate interpretation of the transistor performance without providing information on the gate voltage dependence of mobility and the effects of the contact regions. In this comparative study, the analysis of the contact regions is found to be very important for determining the difference in the performance of two transistors

Preparatory Education of Crews and Passengers for evacuation in Cold Climate (Arctic and Antarctic)

MASTER OF MARITIME OPERATIONS, Maritime StudiesDue to the ongoing climate change, melting ice has opened the door for increased cruise traffic in the polar regions. In the past decades, we have seen a prolific increase in Polar Cruise Tourism, and thereby, more humans are able to visit the Polar Regions. As a result of this, the IMO implemented the Polar Code in 2017 to better prepare seafarers in polar waters in order to ensure maritime safety. Several researches have been carrying out work, after the Polar Code came into force, to evaluate its realization concerning the harsh climatic conditions of the Arctic and Antarctic. Based on the Polar Code requirements, the crew’s preparedness for evacuation and survival in negative temperatures due to remoteness, is somewhat uncertain. Also, the use of safety equipment in the polar climate still is in the discussion, whether sufficient or not. This thesis investigates the cruise crew’s preparedness for an evacuation in the Arctic and Antarctic, according to the Polar Code. Here, gaps in the existing Polar Code Basic and Advanced Training modules were identified with respect to evacuation needs. Questionnaires and interviews were used as the research method to evaluate the insights of the potential target audiences. The study findings were analyzed and reveal the Polar Code’s ineffectiveness with respect to educating the cruise crew for an evacuation, along with the lack of requirement to passenger survival training. This study recommends specific evacuation training for all the cruise crew members based on the actual needs and, subsequently, the need for improvement in the Polar Code training modules. It also proposes survival training modules for cruise passengers to be developed, for evacuation of a vessel in the Arctic and Antarctic.MMO501

Effect of iodine incorporation on characteristic properties of cadmium telluride deposited in aqueous solution

The electrodeposition of polycrystalline I-doped CdTe was successfully performed from aqueous solutions containing cadmium nitrate (Cd(NO3)2 and tellurium oxide (TeO2). The effects of different I-doping concentrations in the electrolytic bath on the deposited CdTe layers deposited were evaluated structurally, optically, morphologically and electronically using X-ray diffraction (XRD), ultraviolet-visible spectrophotometry, scanning electron microscopy, photoelectrochemical cell measurement and direct-current (DC) conductivity test respectively. The XRD show reduction in the (111) cubic CdTe peak intensity and the calculated crystallite size of the CdTe:I layers above 5 ppm I-doping. At I-doping of 1000 ppm of the CdTe-bath and above, the deposition of only crystalline Te due to the formation of Cd-I complexes debarring the deposition of Cd and co-deposition of CdTe in aqueous solution was observed. Morphologically, reductions in grain size were observed above 5 ppm I-doping with high pinhole density and the formation of cracks within the CdTe:I layers. For the as-deposited CdTe:I layers, conduction type remained n-type across all the explored I-doping concentration of 200 ppm. For the CdCl2 and Ga2(SO4)2+CdCl2 treated CdTe:I layers, the transition from n- to p-type conductivity was observed for the CdTe:I baths doped with 20 ppm and above due to the reduced cadmium deposition on the substrate. The highest conductivity was observed at 5 ppm I-doping of the CdTe-bath. Observations made on the CdTe:I in aqueous solution differs from the non-aqueous solvent documented in the literature. These results are reported systematically in this communication

Death within 8 years after childhood convulsive status epilepticus:a population-based study

The risk of long-term mortality and its predictors following convulsive status epilepticus in childhood are uncertain. We report mortality within 8 years after an episode of convulsive status epilepticus, and investigate its predictors from a paediatric, prospective, population-based study from north London, UK. In the current study, we followed-up a cohort previously ascertained during a surveillance study of convulsive status epilepticus in childhood. After determining the survival status of the cohort members, we defined cause of death as that listed on their death certificates. We estimated a standardized mortality ratio to compare mortality in our cohort with that expected in the reference population. Multivariable Cox regression analysis was used to investigate any association between the clinical and demographic factors at the time of status epilepticus and subsequent risk of death. The overall case fatality was 11% (95% confidence interval 7.5–16.2%); seven children died within 30 days of their episode of convulsive status epilepticus and 16 during follow-up. The overall mortality in our cohort was 46 times greater than expected in the reference population, and was predominantly due to higher mortality in children who had pre-existing clinically significant neurological impairments when they had their acute episode of convulsive status epilepticus. Children without prior neurological impairment who survived their acute episode of convulsive status epilepticus were not at a significantly increased risk of death during follow-up. There were no deaths in children following prolonged febrile convulsions and idiopathic convulsive status epilepticus. A quarter of deaths during follow-up were associated with intractable seizures/convulsive status epilepticus, and the rest died as a complication of their underlying medical condition. On regression analysis, presence of clinically significant neurological impairments prior to convulsive status epilepticus was the only independent risk factor for mortality. In conclusion, there is a high risk of death within 8 years following childhood convulsive status epilepticus but most deaths are not seizure related. Presence of pre-existing clinically significant neurological impairments at the time of convulsive status epilepticus is the main risk factor for mortality within 8 years after the acute episode. The attributable role of convulsive status epilepticus on mortality remains uncertain, but appears less than is generally perceived

한국의 사이버 여성권리 및 인권. 출현, 특성 및 결과

The massification and widespread of the available tools on Internet contributes togive shape and movement to the contemporary social and political life.The variety of information and communication possibilities converges in the formation of groups and movements with shared interests and identities. In this context, in the Republic of Korea, feminist groups have emerged and proliferated promoting their demands in a quickly, anonymous and simultaneous way and were nourished by the wide possibilities offered by the cyberspace.The objective of this paper is to analyze the circumstances that motivated the conformation of these feminist groups on the web, defined under the conceptual framework of cyberfeminism, its characteristics and the consequences of its actions at a cultural and political level. This information allows us to outline the possibilities of its future development.The analysis dimensions include: the member?s characteristics, the collaboration?s types, the topics of interest, the action?s modalities, and the positioning with respect to the LGBT community.We consider that cyberfeminism has gained considerably social importance in South Korea and has influenced public opinion, also affecting the establishment of public policy agenda.The methodological approach, of qualitative nature, is nourished by previous ownresearch, specialized literature, and information collected/gathered from IT tools thatprovide/allow the analysis of our object of study. This paper considers contextual variables, such as the internet expansion and the feminism history in the country, in order to analyze the structuration of the feminist movement online.The general results achieved about cyberfeminism in Korea are focus on the member's characteristic, the types of collaboration between its members, the topics of interest, the modality of action and their positioning with respect to the demands of the LGBT community in the feminist struggle. Based on the outcomes of the investigation, it concludes with recommendationson how the South Korean feminism can influence society and promote public demonstrations that can result in changes in public policies. It also reflects on the intervention of online groups and the gender dynamics on the internet, which are strongly shaped by globalization.Fil: Bavoleo, Bárbara Inés. Universidad Nacional de La Plata. Facultad de Ciencias Jurídicas y Sociales. Instituto de Relaciones Internacionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Chaure, Desirée. Universidad Nacional de La Plata. Facultad de Ciencias Jurídicas y Sociales. Instituto de Relaciones Internacionales; Argentin