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•A novel operation strategy based on minimum distance which is flexible and adaptable was proposed.•An integrated evaluation criterion reflecting the matching performance was ...presented.•The strategy and criterion was used to optimize the design of the CCHP system.
A novel operation strategy based on minimum distance was proposed. Also, an integrated evaluation criterion which can reflect the matching performance between the CCHP (combined cooling, heating and power) system and the building was presented. A hospital in Shanghai was used to evaluate the CCHP system with the proposed strategy using the proposed evaluation criterion. The proposed operation strategy was compared with FEL (following the electric load), FTL (following the thermal load) and FHL (following hybrid electric-thermal load) strategies. The results show that the matching performance evaluation criterion is reasonable and integrated. The system with a better matching performance would be fully used and maintain high efficiency. Compared with FEL, FTL and FHL strategies, the proposed operation strategy is flexible and adaptable, which can lead to a better matching performance for a CCHP system. In the case study, the optimized power generation unit capacity and weightings of the optimized operation strategy are 900kW and w1,above equals to 0.4, w1,below equals to 0.1, respectively.
External signal steady magnetic field and electric-magnetic compound field were applied to investigate the influence of the electromagnetic field to the laser cladding NiCrBSi coatings. The ...macromorphology, phase composition and microstructure were identified by optical microscope (OM), confocal scanning laser microscope (CSLM), X-ray diffraction (XRD) and scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS). The experimental results demonstrated that the main phase composition of the coatings was γ-(Fe,Ni), Cr23C6, Cr7C3, CrB, Ni3B with and without electromagnetic fields. Results showed that the dilution of the coating under electric-magnetic compound field was similar (14%) to the coating without auxiliary field. While the dilution of the coating had a decrease (10.8%) under signal steady magnetic field. Results of microstructure indicated the content of CrB phase in the coating increased obviously under electromagnetic field. The average microhardness of the coating under electromagnetic field was increased compared to that of the coating without auxiliary field. Corrosion resistance was also improved under electromagnetic field auxiliary laser cladding.
•Electromagnetic field can change the dilution rate of the coating.•The steady magnetic field can suppress the diffusion of element.•Electromagnetic field can improve the microhardness and corrosion resistance of coating.•Electromagnetic field does not affect the type of coating phase.
Previous studies have shown that diffusion tensor imaging suggests a diffuse loss of white matter integrity in people with white matter hyperintensities or lacunes. The purpose of this study was to ...investigate whether the presence of cerebral microbleeds and their distribution are related to the integrity of white matter microstructures.
The study comprised 982 participants who underwent brain MR imaging to determine microbleed status. The cross-sectional relation between microbleeds and the microstructural integrity of the white matter was assessed by 2 statistical methods: a multilinear regression model based on the average DTI parameters of normal-appearing white matter and Tract-Based Spatial Statistics analysis, a tract-based voxelwise analysis. Fiber tractography was used to spatially describe the microstructural abnormalities along WM tracts containing a cerebral microbleed.
The presence of cerebral microbleeds was associated with lower mean fractional anisotropy and higher mean diffusivity, axial diffusivity, and radial diffusivity, and the association remained when cardiovascular risk factors and cerebral small-vessel disease markers were further adjusted. Tract-Based Spatial Statistics analysis indicated strictly lobar cerebral microbleeds associated with lower fractional anisotropy, higher mean diffusivity, and higher radial diffusivity in the internal capsule and corpus callosum after adjusting other cerebral small-vessel disease markers, while only a few voxels remained associated with deep cerebral microbleeds. Diffusion abnormalities gradients along WM tracts containing a cerebral microbleed were not found in fiber tractography analysis.
Cerebral microbleeds are associated with widely distributed changes in white matter, despite their focal appearance on SWI.
•A feed in tariff policy ensuring both energy and economic performance was proposed.•The proposed policy is the best choice in all climate zones except the hottest zone.•If improving PER is ...attractive, FTL is the best choice under the proposed policy.•The effect of policy improving performance reduces from cold zone to hot zone.
In this paper, a feed-in tariff policy which can contribute to both energy and economic performance of a CCHP system is proposed. By applying this feed-in tariff policy, the impact on design optimization (power generation unit capacity and operation strategy) and system performance (economic, energy, and matching performance) of a hospital CCHP system used in different climate zones are evaluated and analyzed. In policy one (Pol1), no electricity is allowed to be sold. In policy two (Pol2), the electricity selling price is constant. In policy three (Pol3), the selling price of electricity is proportional to the PER (Primary Energy consumption Ratio) of the system when the PER is not lower than a critical value. Otherwise, the selling price is zero. The results show that Pol3 can ensure both energy and economic performances of CCHP system. The effect of feed-in tariff policy to improve the performance of CCHP system reduces gradually from the cold zone to the hot zone. Multi-criteria decision making results show that Pol3 with reasonable parameters is the best choice in all climate zones except for the hottest zone in this study. When improving PER is attractive, following thermal load operation strategy is the best choice under Pol3. In the hottest zone of this study, little excess electricity would be produced and sold to the grid. Feed-in tariff policy has little help to improve the economic and energy performance in this zone.
Abstract Background Peroxiredoxin-1 (Prx-1) is an important protector for redox damage and its abnormal expression is continually reported in various tumors. This study aims to investigate the ...expression status of Prx-1 and evaluate its clinical value in pancreatic cancer. Methodology Immunohistochemistry was used to detect Prx-1 expression in pancreatic cancer tissues and para-cancerous tissues. Enzyme-linked immunosorbent assay (ELISA) method was applied to detect the serum Prx-1 levels. Results The immunohistochemical results indicated that positive rate of Prx-1 was ( p < 0.05) higher in pancreatic cancer tissues (74.4%) than in para-cancerous tissues (37.2%). Prx-1 expression was positively correlated with vascular endothelial growth factor (VEGF) and microvessel density (MVD) in cancer tissues. The ELISA results showed that patients with pancreatic cancer had a higher serum Prx-1 level than healthy subjects (31.2 ± 13.5 vs. 13.2 ± 11.9 ng/ml, p < 0.001). Prx-1 expression was correlated with aggressive clinicopathological parameter. The combination of serum Prx-1 and CA19-9, the area under the curve (AUC) was significantly higher than Prx-1 separate. Positive Prx-1 expression was correlated with disappointing overall survival (OS) ( p = 0.002) and disease-free survival (DFS) ( p < 0.001). Multivariate analysis showed that Prx-1 staining as an independent biomarker of poor OS ( p = 0.035) and DFS ( p < 0.001). Conclusion These findings suggest that the levels of Prx-1 expression are significantly increased in pancreatic cancer. The up-regulated Prx-1 is closely related to tumor angiogenesis and acts as a promising tumor marker for diagnosis and prognosis of pancreatic cancer.
•The statistical methods are used in the influence analysis of the optimal design and performance of CCHP systems.•The regression models between building energy demand indexes and the design and ...performance parameters are built.•The design and performance features of CCHP systems for 16 building across 7 climate zones are analyzed.•Some instructive conclusions on the promotion of CCHP systems are summarized.
Combined cooling, heating and power (CCHP) is a promising technology to provide energy for various energy consumers for its good economic, energy and environmental performance. However, the widely promotion of CCHP is hindered by its complex design and varying performance under different situations. In this paper, the influence of energy demands, operation strategy and thermal energy storage strategy on optimal design and performance of CCHP systems is studied by using statistical methods 13,472 energy demand samples for 16 types of building across 7 climate zones in the U.S. are used in the paper. On the whole, building energy demands are the most influential factor. Among the building types, the performance of large hotel, hospital and outpatient healthcare is outstanding. Among the climate zones, CCHP systems have better performance in cold and very cold climate zones. For operation strategies, the ATCSR and PESR values of the FTL mode are averagely less than those of the FEL mode, and the differences between the two modes for ATCSR and PESR are on average 0.25% and 1.03%, respectively. Besides, the use of thermal energy storage can improve the integrated performance of CCHP. In the FEL-TES mode, the average increments of ATCSR and PESR are 0.82% and 0.79%, respectively. In the FTL-TES mode, the average increments of ATCSR and PESR mode can reach 3.42% and 3.46%, respectively. The relationship between building energy demand indexes and the design and performance parameters of the CCHP is also explored by stepwise regression method to build regression models and determine the most effective parameters.
The current study investigates the grain refinement of an Al-7wt%Si alloy with addition of Al–V–B master alloy. It is found that the Al–V–B master alloys can overcome the Si poison effect on grain ...refinement and refine the as cast grain structure of the Al-7wt%Si alloy effectively. A remarkable grain refinement has been achieved by using an Al–3V–1B master alloy with the combined inoculation of 0.015 wt% V and 0.005 wt% B, compared to that obtained by separate inoculation of Al–5V and Al–3B master alloys with the same concentrations of V and B. The corresponding XRD analysis on the Al–5V and Al–3V–1B master alloys and extracted particles from the Al–3V–1B master alloy show that the active nuclei are VB2 particles. The employment of the new Al–3V-1.28B master alloy optimized according to the atomic ratio of V:B = 1:2 produced the finest grain size in the Al-7wt.%Si alloy compared with the commercial Al–3Ti–1B and Al–5Ti–1B master alloys. This study indicates that the Al–V–B master alloy has the potential to be an effective grain refiner for Al–Si alloys.
•A new potential grain refiner for Al–Si alloys, Al–V–B refiner, is employed to induce the grain refinement.•The optimized Al–V–B refiner can produce the finest grain size in the Al-7wt.%Si alloy compared with the Al–Ti–B refiners.•VB2 particles supplied by Al–V–B master alloy are the active nuclei for heterogeneous nucleation in Al-7wt.%Si alloy.
Electrically tunable dielectric materials have potential applications as various microwave devices, such as tunable oscillators, phase shifters and varactors. High dielectric tunability, low ...dielectric loss tangent and appropriate level of dielectric constant, are basic requirements for such applications. Ferroelectric materials are the most promising candidates. In general, strontium titanate (SrTiO3 or ST) is used for devices operating at low temperatures, while the devices based on barium strontium titanate (Ba1a degree x Sr x TiO3 or BST) are operated at room temperatures. The modifications of parent ferroelectrics, such as Sr1a degree x Pb x TiO3, BaZr x Ti1a degree x O3 and BaTi1a degree x Sn x O3 etc., have also been widely investigated. In addition, there have been reports on electrically tunable dielectric materials, based on non-ferroelectric compounds, such as microwave dielectrics and carbon nanotube (CNT) composites. Specifically for ferroelectric materials, a critical issue is the reduction of the dielectric losses, because their dielectric loss tangents are relatively high for practical device applications. Recently, many efforts have been made in order to reduce the dielectric losses of BST based ferroelectrics. An efficient way is to dope oxides that have low dielectric losses, such as MgO, ZrO2 and Al2O3, TiO2, LaAlO3, and Bi1.5ZnNb1.5O7 etc., into the ferroelectric materials. In addition to the reduction in dielectric loss tangents, the introduction of oxides would also be able to modify the dielectric constant to be suitable for practical design of various devices. Meanwhile, dielectric and electrical properties of thin films can be improved by chemical doping, substrate adaptation, orientation and anisotropy optimization. This review provides an overall summary on the recent progress in developing electrically tunable dielectric materials, based on ferroelectrics and non-ferroelectrics, with a specific attention to the strategies employed to improve the performances of ferroelectric materials for microwave device applications.
•Electromagnetic field does not change the phase composition of the coating.•Electromagnetic field can change the temperature gradient.•Electromagnetic field can improve the microstructure of the ...coating.•Electromagnetic field can reduce the cracks and improve the microhardness of the coating.
Laser cladding Ni-base coatings were prepared on pure iron assisted by an electromagnetic compound field. The microstructure, phase composition, crack and microhardness of the cladding coatings were investigated. Results indicated that laser cladding Ni-base coatings with and without the electromagnetic field was composed of γ-(Fe, Ni), CrB, Cr7C3, Ni3B and Ni2B. The electromagnetic compound field could promote the transformation of γ-(Fe, Ni) to equiaxed crystals. The volume fraction of hard phase CrB can be increased by electromagnetic field. Mechanical scouring effect of electromagnetic stirring makes hard phase Cr7C3 form an independent rod structure. The number of cracks in coatings is decreased under the electromagnetic field. The average microhardness of cladding coatings increased to 923.7 HV0.2. Under the combined action of the electromagnetic stirring and current thermal effect, the temperature gradient in the molten pool had an optimum value. That is, the value of AC current was 1200 A and magnetic flux intensity was 0.2 T.
Based upon 14 field surveys conducted between 2003 and 2008, we showed that the seasonal pattern of sea surface partial pressure of CO2 (pCO2 ) and sea-air CO2 fluxes differed among four different ...physical-biogeochemical domains in the South China Sea (SCS) proper. The four domains were located between 7 and 23° N and 110 and 121° E, covering a surface area of 1344 × 103 km2 and accounting for ~ 54% of the SCS proper. In the area off the Pearl River estuary, relatively low pCO2 values of 320 to 390 μatm were observed in all four seasons and both the biological productivity and CO2 uptake were enhanced in summer in the Pearl River plume waters. In the northern SCS slope/basin area, a typical seasonal cycle of relatively high pCO2 in the warm seasons and relatively low pCO2 in the cold seasons was revealed. In the central/southern SCS area, moderately high sea surface pCO2 values of 360 to 425 μatm were observed throughout the year. In the area west of the Luzon Strait, a major exchange pathway between the SCS and the Pacific Ocean, pCO2 was particularly dynamic in winter, when northeast monsoon induced upwelling events and strong outgassing of CO2 . These episodic events might have dominated the annual sea-air CO2 flux in this particular area. The estimate of annual sea-air CO2 fluxes showed that most areas of the SCS proper served as weak to moderate sources of the atmospheric CO2 , with sea-air CO2 flux values of 0.46 ± 0.43 mol m-2 yr-1 in the northern SCS slope/basin, 1.37 ± 0.55 mol m-2 yr-1 in the central/southern SCS, and 1.21 ± 1.48 mol m-2 yr-1 in the area west of the Luzon Strait. However, the annual sea-air CO2 exchange was nearly in equilibrium (-0.44 ± 0.65 mol m-2 yr-1 ) in the area off the Pearl River estuary. Overall the four domains contributed (18 ± 10) × 1012 g C yr-1 to the atmospheric CO2 .
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