16 research outputs found
Multipulse operation of a Ti:sapphire laser mode locked by an ion-implanted semiconductor saturable-absorber mirror
Multipulse operation was demonstrated with a Ti:sapphire laser mode-locked by a semiconductor saturable absorber mirror. Widely separated double, triple, and quadruple pulses with irregular spacing were observed. In addition, closely coupled states were also found that could be attributed to interplay between saturable absorber and filter losses, saturated gain and the coherent interaction of solitons. These observations, as well as the mechanisms in the transitions from single to multipulse states are explained within the framework of the generalized complex Ginzburg-Landau equation as the laser master equation.Peer Reviewe
Perekonomian Indonesia dalam Menghadapi Sistem Globalisasi
Globalisation is a part of human being. Until now, there arenÂŽt succes for a nation without relation and assosiation to other countries. Indonesia hope, that globalisation can continue the national economic market system to the international level. What is our attitude to face it? what is the agenda need to be prepared? Preparing non market institution is a key toface globalisation and executing more effective diplomacy. Keywords:Globalisation, Economic market system
TRY plant trait database â enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
A milliliter-scale setup for the efficient characterization of multicomponent vapor-liquid equilibria using raman spectroscopy
Vapor-liquid equilibrium (VLE) data are of major importance for the chemical industry. Despite significant progress in predictive methods, experimental VLE data are still indispensable. In this work, we address the need for experimental VLE data. Commonly, the characterization of VLE requires significant experimental effort. To limit the experimental effort, VLE measurements are frequently conducted by synthetic methods which employ samples of known composition and avoid complex analytics and sampling issues. In contrast, analytical methods provide independent information on phase compositions, commonly based on sampling and large amounts of substance. In the first part of this work, we employ a synthetic method, the well-established Cailletet setup, to characterize the high pressure VLE of two promising binary biofuel blends. The Cailletet method serves as a state of the art reference method that enables collecting data of remarkable accuracy. However, extensive infrastructure is needed. In the second part, to avoid extensive infrastructure and overcome limitations of previous methods, we develop a novel analytical milliliter-scale setup for the non-invasive and efficient characterization of VLE: RAMSPEQU (Raman Spectroscopic Phase Equilibrium Characterization). The novel setup saves substance and rapidly characterizes VLE. Sampling and its associated errors are avoided by analyzing phase compositions using Raman spectroscopy. Thereby, volumes of less than 3 ml are sufficient for reliable phase equilibrium measurements. To enable rapid data generation and save substance, we design an integrated workflow combining Raman signal calibration and VLE measurement. As a result, RAMSPEQU gives access to up to 15 pTxy-data sets per workday. RAMSPEQU is successfully validated against pure component and binary VLE data from literature. However, mixtures with only two components rarely depict real industrial applications. As the number of experiments increases strongly with a rising number of components, the efficient RAMSPEQU setup seems particularly suited for multicomponent systems. In the third part of this work, we employ the RAMSPEQU setup for the characterization of a quaternary system and its binary subsystems. 22 ml and 105 ml of the binary and quaternary mixtures are sufficient for an extensive VLE characterization. The RAMSPEQU setup and its integrated workflow enable the characterization of multicomponent VLE while saving significant amounts of substance and laboratory time