1,411 research outputs found
Satlc model lesson for teaching and learning complex environmental issues related to the thermodynamics
Environmental chemistry is one of the disciplines of Science. For the goal of the deep learning of the subject, it is indispensable to present perception and models of chemical behaviour explicitly. This can be accomplished by giving careful consideration to the development of concepts such that newer approaches are given contemplation, taking in consideration participation of students. Students, well versed in issues which integrate to enhance vital concepts, are thus able to understand nature and help us to discover means to view the impact of industrialization on the well being of mankind. Understanding environmental chemistry needs quality teaching at undergraduate stage of students learning. In the absence of necessary input of biological sciences, mathematics, statistics, along with the parameters of analytical and physical chemistry, students often find environmental chemistry a difficult subject. It is therefore desirable that the practice of disseminating knowledge related to environmental chemistry must avoid the tradition of presenting the necessary information separated from each other. The lectures should be designed in such a way that they provide the complete description of any issue debated in the class room. The students have not to be encouraged to address the issue in a sphere of limited knowledge. It is suggested that the teachers organize their lectures in such a way that the student get involved in the class. This essential scenario can only develop when the knowledge is transferred through Systemic diagrams. Recently concept based teaching methodology; namely systemic approach to teaching and learning chemistry (SATLC) has been employed to highlight the connectivity between some environmental issues and the disciplines of Physical Chemistry. [African Journal of Chemical Education—AJCE 5(2), July 2015
Phonon-Induced Rabi-Frequency Renormalization of Optically Driven Single InGaAs/GaAs Quantum Dots
The authors thank the EPSRC (U.K.) EP/G001642, and the QIPIRC U.K. for financial support. A. N. is supported by the EPSRC and B.W. L. by the Royal Society.We study optically driven Rabi rotations of a quantum dot exciton transition between 5 and 50 K, and for pulse areas of up to 14 pi. In a high driving field regime, the decay of the Rabi rotations is nonmonotonic, and the period decreases with pulse area and increases with temperature. By comparing the experiments to a weak-coupling model of the exciton-phonon interaction, we demonstrate that the observed renormalization of the Rabi frequency is induced by fluctuations in the bath of longitudinal acoustic phonons, an effect that is a phonon analogy of the Lamb shift.Peer reviewe
Macrocyclic cyanocobalamin (vitamin B12) as a homogeneous electrocatalyst for water oxidation under neutral conditions
Highly water-soluble cyanocobalamin (also known as vitamin B-12) is the most structurally macrocyclic complex comprising cobalt in the center of a corrin ring. Interestingly, it acts as a robust electrocatalyst in water oxidation at similar to 0.58 V overpotential with a faradaic efficiency of 97.50% under neutral buffered conditions. The catalyst is impressively stable even after long-term bulk electrolysis, and homogeneous in nature, as established by a series of experiments and characterization techniques
Colorectal Cancer Screening Behaviors among American Indians in the Midwest
Colorectal cancer is the second most diagnosed cancer among American Indians and is also the second leading cause of cancer death. We used a community-based participatory approach to conduct a mixed methods study to examine colorectal cancer screening behaviors. Here we report on the screening behaviors of our focus group participants (n=153). There were significant gender differences in the colorectal cancer screening rates for FOBT and colonoscopy. Although over 80% of participants reported having health insurance, only 35% of males over 50 years old and 57% of females reported ever having a colonoscopy. More research is needed to identify the causes of gender differences in colorectal cancer screening rates among American Indians. The results of the current study provide new information on the prevalence of colorectal cancer screening among American Indians living in the Midwestern (Kansas and Missouri) portion of the country
Efficient high-fidelity quantum computation using matter qubits and linear optics
We propose a practical, scalable, and efficient scheme for quantum
computation using spatially separated matter qubits and single photon
interference effects. The qubit systems can be NV-centers in diamond,
Pauli-blockade quantum dots with an excess electron or trapped ions with
optical transitions, which are each placed in a cavity and subsequently
entangled using a double-heralded single-photon detection scheme. The fidelity
of the resulting entanglement is extremely robust against the most important
errors such as detector loss, spontaneous emission, and mismatch of cavity
parameters. We demonstrate how this entangling operation can be used to
efficiently generate cluster states of many qubits, which, together with single
qubit operations and readout, can be used to implement universal quantum
computation. Existing experimental parameters indicate that high fidelity
clusters can be generated with a moderate constant overhead.Comment: 5 pages, 3 figures, broader introduction and improved scalability of
cluster state generatio
Long-lived spin entanglement induced by a spatially correlated thermal bath
We investigate how two spatially separated qubits coupled to a common heat
bath can be entangled by purely dissipative dynamics. We identify a dynamical
time scale associated with the lifetime of the dissipatively generated
entanglement and show that it can be much longer than either the typical
single-qubit decoherence time or the time scale on which a direct exchange
interaction can entangle the qubits. We give an approximate analytical
expression for the long-time evolution of the qubit concurrence and propose an
ion trap scheme in which such dynamics should be observable.Comment: 5 pages, 2 figure
Life assessment prognostic modelling for multi-layered coating systems using a multidisciplinary approach
The multi-disciplinary approach has been adopted to model the formation and propagation of blistering effect for evaluation of useful coating life in the multi-layered coating-substrate system. Prognostic model of de-bonding driving force has been formulated as a function of material science, solid mechanics and fracture mechanics properties to estimate critical, safe and fail conditions of the coating-substrate system. The blister growth velocity rate is also included in the developed model to estimate the blister propagation as a function of diffusion-induced stress and residual stress. The proposed prognostic modelling for the formation and propagation of blistering effect are combined to form an assessment model for evaluation of useful coating life of the multi-layered coating-substrate system and validated through experimental observation
Selective spin coupling through a single exciton
We present a novel scheme for performing a conditional phase gate between two
spin qubits in adjacent semiconductor quantum dots through delocalized single
exciton states, formed through the inter-dot Foerster interaction. We consider
two resonant quantum dots, each containing a single excess conduction band
electron whose spin embodies the qubit. We demonstrate that both the two-qubit
gate, and arbitrary single-qubit rotations, may be realized to a high fidelity
with current semiconductor and laser technology.Comment: 5 pages, 3 figures; published version, equation formatting improved,
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