42 research outputs found

    Coherence memory and amnesia in a mode-locked laser

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    Self-organization of temporal modes in mode-locked lasers usually starts from quantum noise. In this process, incoherent spontaneous emission is steered into coherent ultrashort pulses by dissipation and nonlinearity. In this work, we investigated self-organization dynamics in a mode-locked Mamyshev oscillator starting from coherent pulse seeds as opposed to quantum noise. We observed that the coherence of the seed can be remembered or forgotten depending on the initial inverse population. The excessive nonlinearity in the coherence amnesia regime can devastate the seed coherence, causing the oscillator to undergo a chaotic transition lasting hundreds of round trips before regaining coherence. Conversely, the oscillator converges in only a few round trips for the coherence memory regime. A heterodyne technique was developed to record the fast varying optical phase and characterize these two regimes. Dissipative soliton molecules were synthesized from external pulse pair seeds via the coherence memory pathway. In this case, a plateau of the generated pulse spacing independent from seed pulse spacing, i.e., amnesia of the seed spacing, was observed for close spaced seed pulse pairs. Moreover, we show that pulse seeds can be used for laser reconfiguration and pulse pattern control. Our work paves a way to control transient pulse dynamics and steady pulse forms on demand in mode-locked lasers

    GLISP: A Scalable GNN Learning System by Exploiting Inherent Structural Properties of Graphs

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    As a powerful tool for modeling graph data, Graph Neural Networks (GNNs) have received increasing attention in both academia and industry. Nevertheless, it is notoriously difficult to deploy GNNs on industrial scale graphs, due to their huge data size and complex topological structures. In this paper, we propose GLISP, a sampling based GNN learning system for industrial scale graphs. By exploiting the inherent structural properties of graphs, such as power law distribution and data locality, GLISP addresses the scalability and performance issues that arise at different stages of the graph learning process. GLISP consists of three core components: graph partitioner, graph sampling service and graph inference engine. The graph partitioner adopts the proposed vertex-cut graph partitioning algorithm AdaDNE to produce balanced partitioning for power law graphs, which is essential for sampling based GNN systems. The graph sampling service employs a load balancing design that allows the one hop sampling request of high degree vertices to be handled by multiple servers. In conjunction with the memory efficient data structure, the efficiency and scalability are effectively improved. The graph inference engine splits the KK-layer GNN into KK slices and caches the vertex embeddings produced by each slice in the data locality aware hybrid caching system for reuse, thus completely eliminating redundant computation caused by the data dependency of graph. Extensive experiments show that GLISP achieves up to 6.53×6.53\times and 70.77×70.77\times speedups over existing GNN systems for training and inference tasks, respectively, and can scale to the graph with over 10 billion vertices and 40 billion edges with limited resources

    Gynecomastia during imatinib mesylate treatment for gastrointestinal stromal tumor: a rare adverse event

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    <p>Abstract</p> <p>Background</p> <p>Imatinib mesylate has been the standard therapeutic treatment for chronic myeloid leukemia, advanced and metastatic gastrointestinal stromal tumor (GIST). It is well tolerated with mild adverse effects. Gynecomastia development during the course of treatment has been rarely reported.</p> <p>Methods</p> <p>Ninety-eight patients with advanced or recurrent GIST were treated with imatinib mesylate. Among the fifty-seven male patients six developed gynecomastia during the treatment. The lesions were confirmed by sonography. Sex hormone levels were determined in six patients with and without the presence of gynecomastia respectively. The patients with gynecomatia were treated with tamoxifene and the sex hormones were assayed before and after tamoxifene treatment.</p> <p>Results</p> <p>In patients with gynecomastia the lump underneath the bilateral nipples was 2.5 to 5 centimeters in diameter. Their serum free testosterone levels ranged between 356.61 and 574.60 ng/dl with a mean ± SD of 408.64 ± 82.06 ng/dl (95% CI 343.03~474.25 ng/dl), which is within the normal range. The level of serum estradiol was 42.89 ± 16.54 pg/ml (95% CI 29.66~56.12 pg/ml). Three patients had higher levels (43.79~71.21 pg/ml) and the others' were within normal range of 27.00~34.91 pg/ml. Six patients without the development of gynecomastia had normal free testosterone. One patient died because of large tumor burden. The sex hormones had no significant changes before and after tamoxifene treatment.(<it>P </it>> 0.05)</p> <p>Conclusions</p> <p>Testosterone levels were not decreased in the six GIST patients with gynecomastia. Three patients had increased serum estradiol level which suggests that imbalance of sex hormones may be the cause of gynecomastia during treatment with imatinib mesylate.</p

    Opening to the Outside World in Northeast China and Economic Cooperations in Northeast Asia

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    Since Deng Xiaoping's speech during his inspection tour to the South of China, China's reform and opening has begun to get into a new development stage, and the Northeast China's opening to the outside world has begun to take a new step forward. 1. The Tumen River Area development has made a substantive progress. 2. A New Goal has been set for the East Liaoning Peninsula's Opening to the Outside World. 3. The frontier trade between Russia, DPRK and China has been developing rapidly. With the relaxation of the political situations in Northeast Asia, the economic cooperations among the countries, the areas has begun developing rapidly on the basis of mutual economic complement. But because it is composed of countries of different social systems, there exist in politics south-to-north relationships and in economic development great difference. All this determines the complex nature of the economic cooperation there and makes it different from other economic areas in the following characteristics: 1. The Countries in Northeast Asia have a characteristics of internal trade structure on the basis of natural economic connection. 2. Trade structure of multiple axis will be fonned by puting vertical division of labour in proper place developing horisontal one. 3. Economic cooperation systems of multiple levels are to be formed with Japan, ROK and China as the cores

    Room temperature stable E,Z-diphosphenes: their isomerization, coordination, and cycloaddition chemistry

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    E,Z-isomers display distinct physical properties and chemical reactivities. However, investigations on heavy main group elements remain limited. In this work, we present the isolation and X-ray crystallographic characterization of N-heterocyclic vinyl (NHV) substituted diphosphenes as both E-and Z-isomers (L= CH-P=P-CH=L, E,Z-2b; L =N-heterocyclic carbene). E-2b is thermodynamically more stable and undergoes reversible photo-stimulated isomerization to Z-2b. The less stable Z-isomer Z-2b can be thermally reverted to E-2b. Theoretical studies support the view that this E Z isomerization proceeds via P=P bond rotation, reminiscent of the isomerization observed in alkenes. Furthermore, both E,Z-2b coordinate to an AuCl fragment affording the complex [AuCl(n(2)-Z-2b)] with the diphosphene ligand in Z-conformation, exclusively. In contrast, E,Z-2b undergo [2 + 4] and [2 + 1] cycloadditions with dienes or diazo compounds, respectively, yielding identical cycloaddition products in which the phosphorus bound NHV groups are in trans-position to each other. DFT calculations provide insight into the E/Z-isomerisation and stereoselective formation of Au(I) complexes and cycloaddition products.ISSN:2041-6520ISSN:2041-653

    Making the unconventional mu(2)-P bridging binding mode more conventional in phosphinine complexes

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    Phosphinines, as aromatic heterocycles, usually engage in coordination as η1-P σ-complexes or η6-phosphinine π-complexes. The μ2-P bridging coordination mode is rarely observed. With the aim to study the effect of different electronic configurations of phosphinines on the coordination modes, a series of anionic phosphinin-2-olates and neutral phosphinin-2-ols were prepared with moderate to high yield. Then the coordination chemistry of these two series was studied in detail towards coinage metals (Au(I) and Cu(I)). It is observed that the anionic phosphinin-2-olates possess a higher tendency to take a bridging position between two metal centers compared to the neutral phosphinin-2-ols. Based on these experimental findings bolstered by DFT calculations, some insight is gained on how the unconventional μ2-P phosphinine bridging coordination mode can be made more conventional and used for the synthesis of polynuclear complexes.ISSN:2041-6520ISSN:2041-653
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