A Ballistic Graphene Cooper Pair Splitter

We report an experimental study of Cooper pair splitting in an encapsulated graphene based multiterminal junction in the ballistic transport regime. Our device consists of two transverse junctions, namely the superconductor/graphene/superconductor and the normal metal/graphene/normal metal junctions. In this case, the electronic transport through one junction can be tuned by an applied bias along the other. We observe clear signatures of Cooper pair splitting in the local as well as nonlocal electronic transport measurements. Our experimental data can be very well described by using a modified Octavio-Tinkham-Blonder-Klapwijk model and a three-terminal beam splitter model

Engineering graphene by oxidation: a first principles study

Graphene epoxide, with oxygen atoms lining up on pristine graphene sheets, is investigated theoretically in this Letter. Two distinct phases: metastable clamped and unzipped structures are unveiled in consistence with experiments. In the stable (unzipped) phase, epoxy group breaks underneath sp2 bond and modifies the mechanical and electronic properties of graphene remarkably. The foldable epoxy ring structure reduces its Young's modulus by 42.4%, while leaves the tensile strength almost unchanged. Epoxidation also perturbs the pi state and opens semiconducting gap for both phases, with dependence on the density of epoxidation. In the unzipped structures, localized states revealed near the Fermi level resembles the edge states in graphene nanoribbons. The study reported here paves the way for oxidation-based functionalization of graphene-related materials.Comment: 17 pages (4 figures, 1 table

Structural adjustment and forest resources - the impact of World Bank operations

Over two decades, the World Bank has undertaken many structural adjustment operations withgovernments of developing countries. During negotiations for structural adjustment loans (SALs), partner governments agree to specific policy reforms, whose implementation becomes a condition for disbursement of SAL funds. Conditionality varies with local circumstances, but generally supports privatization of state enterprises, liberalization of the domestic economy, and openness in international trade. Structural adjustment operations have often been controversial because they are explicitly political. Opposition, or support reflects ideological perspectives, perceptions of who gains, and who loses economically from a SAL, or beliefs about its environmental, and social impacts. Environmental groups express particular concern about SALs'impacts on the rate of deforestation. Debate about adjustment, and deforestation has been fueled largely by anecdotes, and a few country cases bases on limited time-series data. The authors broaden the analysis by combining a complete record of Bank SAL operations, with a 38-year socioeconomic database for 112 developing countries. They find that adjustment has greatly affected imports, exports, consumption, and production in many forest products sectors (such as fuel-wood, sawn-wood, panels, pulp, and paper). Some activities have increased, and some declined, but overall, the effects have balanced each other. The net impact on domestic round-wood production, the authors'proxy for forest exploitation, has been almost exactly zero. Their results suggest that growth in round-wood production is explained well by population growth, urbanization, and world demand for forest products. Their findings suggest that adjustment has not promoted domestic deforestation, but it has increased net imports of wood products, implying some displacement of pressure onto other countries'forest resources. They also find that devaluations have significantly increased the exploitation of forest resources.Environmental Economics&Policies,Labor Policies,Economic Theory&Research,Silviculture,Consumption,Environmental Economics&Policies,Economic Theory&Research,Silviculture,Forestry,Consumption

Response time correlations for platinum resistance thermometers in flowing fluids

The thermal response of two types of Platinum Resistance Thermometers (PRT's), which are being considered for use in the National Transonic Wind Tunnel Facility, were studied. Response time correlations for each PRT, in flowing water, oil and air, were established separately. A universal correlation, tau WOA = 2.0 + 1264, 9/h, for a Hy-Cal Sensor (with a reference resistance of 100 ohm) within an error of 20% was established while the universal correlation for the Rosemount Sensor (with a reference resistance of 1000 ohm), tau OA = 0.122 + 1105.6/h, was found with a maximum percentage error of 30%. The correlation for the Rosemount Sensor was based on air and oil data only which is certainly not sufficient to make a correlation applicable to every condition. Therefore, the correlation needs more data to be gathered in different fluids. Also, it is necessary to state that the calculation of the parameter, h, was based on the available heat transfer correlations, whose accuracies are already reported in literature uncertain within 20-30%. Therefore, the universal response constant correlations established here for the Hy-Cal and Rosemount sensors are consistent with the uncertainty in the input data and are recommended for future use in flowing liquids and gases