A Novel Manufacturing Approach of Phase-change Heat Sink for High-power LED

AbstractHeat removal in packaged high-power light-emitting diode (LED) chips is critical to device performance and reliability. Thermal performance of LEDs is important in that lowered junction temperatures extend the LED's lifetime at a given photometric flux. Optionally, lower thermal resistance can enable increased brightness operation without exceeding the maximum allowable junction temperature for a given lifetime. The goal of this study is to improve the thermal characteristics of high-power LED package by using phase change heat sink. The heat-release characteristics of high-power LED package are analyzed and a novel phase change heat sink with 3D integral-fin boiling structures for high-power LED is developed. Two different fin structures were obtained in grooves formed with chopping-ploughing-extrusion compound forming technology and observed by scanning electron microscope (SEM)

Hybrid Artificial Root Foraging Optimizer Based Multilevel Threshold for Image Segmentation

This paper proposes a new plant-inspired optimization algorithm for multilevel threshold image segmentation, namely, hybrid artificial root foraging optimizer (HARFO), which essentially mimics the iterative root foraging behaviors. In this algorithm the new growth operators of branching, regrowing, and shrinkage are initially designed to optimize continuous space search by combining root-to-root communication and coevolution mechanism. With the auxin-regulated scheme, various root growth operators are guided systematically. With root-to-root communication, individuals exchange information in different efficient topologies, which essentially improve the exploration ability. With coevolution mechanism, the hierarchical spatial population driven by evolutionary pressure of multiple subpopulations is structured, which ensure that the diversity of root population is well maintained. The comparative results on a suit of benchmarks show the superiority of the proposed algorithm. Finally, the proposed HARFO algorithm is applied to handle the complex image segmentation problem based on multilevel threshold. Computational results of this approach on a set of tested images show the outperformance of the proposed algorithm in terms of optimization accuracy computation efficiency

A comparison of the performance of 68Ga-Pentixafor PET/CT versus adrenal vein sampling for subtype diagnosis in primary aldosteronism

ObjectiveTo investigate the diagnostic efficiency and prognostic value of 68Ga-Pentixafor PET/CT in comparison with adrenal vein sampling (AVS) for functional lateralization in primary aldosteronism (PA). Histology and long-term clinical follow-up normally serve as the gold standard for such diagnosis.MethodsWe prospectively recruited 26 patients diagnosed with PA. All patients underwent 68Ga-Pentixafor PET/CT and AVS. Postsurgical biochemical and clinical outcomes of patients with unilateral primary aldosteronism (UPA), as diagnosed by PET/CT or AVS, were assessed by applying standardized Primary Aldosteronism Surgical Outcome (PASO) criteria. Immunohistochemistry (IHC) was performed to detect the expression of aldosterone synthase (CYP11B2) and CXCR4.ResultsOn total, 19 patients were diagnosed with UPA; of these, 13 patients were lateralized by both PET/CT and AVS, four patients were lateralized by PET-only, and two by AVS-only. Seven subjects with no lateralization on AVS and PET received medical therapy. All patients achieved complete biochemical success except one with nodular hyperplasia lateralized by AVS alone. The consistency between PET/CT and AVS outcomes was 77% (20/26). Moreover, CYP11B2-positive nodules were all CXCR4-positive and showed positive findings on PET. Patients who achieved complete biochemical and clinical success had a higher uptake on PET as well as stronger expression levels of CXCR4 and CYP11B2.ConclusionOur analysis showed that 68Ga-Pentixafor PET/CT could enable non-invasive diagnosis in most patients with PA and identify additional cases of unilateral and surgically curable PA which could not be classified by AVS. 68Ga-Pentixafor PET/CT should be considered as a first-line test for the future classification of PA

Artificial root foraging optimizer algorithm with hybrid strategies

In this work, a new plant-inspired optimization algorithm namely the hybrid artificial root foraging optimizion (HARFO) is proposed, which mimics the iterative root foraging behaviors for complex optimization. In HARFO model, two innovative strategies were developed: one is the root-to-root communication strategy, which enables the individual exchange information with each other in different efficient topologies that can essentially improve the exploration ability; the other is co-evolution strategy, which can structure the hierarchical spatial population driven by evolutionary pressure of multiple sub-populations that ensure the diversity of root population to be well maintained. The proposed algorithm is benchmarked against four classical evolutionary algorithms on well-designed test function suites including both classical and composition test functions. Through the rigorous performance analysis that of all these tests highlight the significant performance improvement, and the comparative results show the superiority of the proposed algorithm

Optimal Coordinated Strategy Analysis for the Procurement Logistics of a Steel Group

This paper focuses on the optimization of an internal coordinated procurement logistics system in a steel group and the decision on the coordinated procurement strategy by minimizing the logistics costs. Considering the coordinated procurement strategy and the procurement logistics costs, the aim of the optimization model was to maximize the degree of quality satisfaction and to minimize the procurement logistics costs. The model was transformed into a single-objective model and solved using a simulated annealing algorithm. In the algorithm, the supplier of each subsidiary was selected according to the evaluation result for independent procurement. Finally, the effect of different parameters on the coordinated procurement strategy was analysed. The results showed that the coordinated strategy can clearly save procurement costs; that the strategy appears to be more cooperative when the quality requirement is not stricter; and that the coordinated costs have a strong effect on the coordinated procurement strategy

Dietary supplementation with ketoacids protects against CKD-induced oxidative damage and mitochondrial dysfunction in skeletal muscle of 5/6 nephrectomised rats

Abstract Background A low-protein diet supplemented with ketoacids (LPD + KA) maintains the nutritional status of patients with chronic kidney disease (CKD). Oxidative damage and mitochondrial dysfunction associated with the upregulation of p66SHC and FoxO3a have been shown to contribute to muscle atrophy. This study aimed to determine whether LPD + KA improves muscle atrophy and attenuates the oxidative stress and mitochondrial damage observed in CKD rats. Methods 5/6 nephrectomy rats were randomly divided into three groups and fed with either 22% protein (normal-protein diet; NPD), 6% protein (low-protein diets; LPD) or 5% protein plus 1% ketoacids (LPD + KA) for 24 weeks. Sham-operated rats with NPD intake were used as the control. Results KA supplementation improved muscle atrophy and function in CKD + LPD rats. It also reduced the upregulation of genes related to the ubiquitin-proteasome system and 26S proteasome activity, as well as protein and mitochondrial oxidative damage in the muscles of CKD + LPD rats. Moreover, KA supplementation prevented the drastic decrease in activities of mitochondrial electron transport chain complexes, mitochondrial respiration, and content in the muscles of CKD + LPD rats. Furthermore, KA supplementation reversed the elevation in p66Shc and FoxO3a expression in the muscles of CKD + LPD rats. Conclusions Our results showed that KA supplementation to be beneficial to muscle atrophy in CKD + LPD, which might be associated with improvement of oxidative damage and mitochondrial dysfunction through suppression of p66Shc and FoxO3a

Effect of Temperature on Microstructure and Mechanical Properties of Fe-9Ni-2Cu Steel during the Tempering Process

In this paper, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray stress meter (XRSA), atom probe tomography (APT), hardness, and tensile tests were used to study the effect of tempering temperature on the microstructure and properties of Fe-9Ni-2Cu steel. The results show that after the quenched samples were tempered at 460 °C for 2 h, the hardness values increased from 373 to 397 HV, and elongation also increased from 13% to 16%. With the tempering temperature increasing from 460 to 660 °C, the hardness firstly decreases from 397 to 353 HV and then increases to 377 HV, while the elongation increases to 17% and then decreases to 11%. The variation of the mechanical properties greatly depends on the evolution of the Cu-rich phase and carbides. The precipitation strengthening of the Cu-rich phase and carbides leads to the increase of hardness, but when the precipitate is coarsened, the precipitation strengthening weakens, and then, the hardness increases. When the tempering temperature is 560 °C, a large amount of stable reverse transformation austenite was formed with a content of 7.1%, while the tensile strength reached the lowest value of 1022 MPa and the elongation reached the maximum value of 17%

[Photograph 2012.201.B1243.0096]

Photograph used for a newspaper owned by the Oklahoma Publishing Company

Fare Optimality Analysis of Urban Rail Transit under Various Objective Functions

Urban rail transit fare strategies include fare structures and fare levels. We propose a rail transit line fare decision based on an operating plan that falls under elastic demand. Combined with the train operation plan, considering flat fare and distance-based fare, and based on the benefit analysis of both passenger flow and operating enterprises, we construct the objective functions and build an optimization model in terms of the operators’ interests, the system’s efficiency, system regulation goals, and the system costs. The solving algorithm based on the simulated annealing algorithm is established. Using as an example the Changsha Metro Line 2, we analyzed the optimized results of different models under the two fare structures system. Finally the recommendations of fare strategies are given