Total Focusing Method Approach of Ultrasonic Phased Array Based on Compressed Sensing

Russian Journal of Nondestructive Testing - Nondestructive testing and evaluation technology of the total focusing method (TFM) based on full matrix capture (FMC) is a hot spot in the current array...     

Finding high-impact interdisciplinary users based on friend discipline distribution in academic social networking sites

Scientometrics - Specialized academic social networking sites are gaining popularity in scientific communication. A huge volume of interdisciplinary information is generated when researchers from...     

白玉菇多糖对免疫抑制型小鼠的免疫调节作用

目的:研究白玉菇多糖对免疫抑制型小鼠脾脏、胸腺的免疫调节作用。方法:经超声波辅助热水浸提及Sevage法去蛋白得到白玉菇精多糖(RPHM)。将小鼠随机分为空白对照组、模型对照组、阳性对照组、RPHM低剂量组(30 mg/kg bw/d)、RPHM中剂量组(60 mg/kg bw/d)、RPHM高剂量组(120 mg/kg bw/d),每天同时间段进行灌胃,灌胃15 d,建立环磷酰胺(CPA)免疫抑制型小鼠模型。取小鼠脾脏、胸腺,测定其体重、脏器指数;血清细胞因子、单核-巨噬细胞吞噬能力;外周白细胞、红细胞和血小板计数并观察脾脏、胸腺的形态学。结果:与模型组相比,RPHM中剂量组(60 mg/kg bw/d)、高剂量组(120 mg/kg bw/d)可明显提升免疫抑制型小鼠的毛色、活动情况、身体状况、食欲、体重、脾脏指数和胸腺指数、单核-巨噬细胞吞噬功能、骨髓造血功能等指标;也可在一定程度上提高免疫抑制型小鼠IL-2、IL-12、IFN-γ和TNF-α的水平,并改善IL-6的分泌异常情况;还可明显改善免疫抑制型小鼠脾脏、胸腺的病变,改善结构完整度。结论:RPHM对免疫抑制型小鼠的脾脏和胸腺有明显的免疫调节作用。     

多壁碳纳米管负载FeS2的制备及脱汞性能分析

采用硝酸铁与硫脲在溶剂热反应条件下制备FeS₂，利用物理浸渍法将FeS₂负载至多壁碳纳米管（MWCNTs）上，借助扫描电镜（SEM）、X射线衍射（XRD）、X光电子能谱（XPS）等分析测试手段对制备样品的结构特性进行探究，通过固定床反应器研究模拟烟气氛围下吸附剂对烟气中单质汞的吸附特性。实验考察了不同FeS₂负载量、烟气初始汞浓度、床层温度以及O₂、NO和SO₂对吸附剂脱汞效率的影响。结果表明，制备出的FeS₂分散性较好，呈球状晶体，表面均匀覆盖着MWCNTs，成团簇状。当负载量为10%、反应温度为70℃时，FeS₂/MWCNTs的吸附效果最好，最高脱除效率能达到100%，60min后脱除效率仍有80.3%。TPD脱附曲线和XPS分析结果进一步表明烟气中的Hg⁰被氧化成Hg²⁺以HgS的形式附着在吸附剂表面，证实吸附剂以化学吸附为主。此外，汞脱除效率随初始汞浓度的增加而降低，汞吸附容量却随之增加，60min最高能达到5.1μg/g。酸性气体NO和SO₂的存在，占据了吸附剂表面的活性点位，不利于Hg⁰的吸附，但低浓度NO对吸附剂的整体效果影响不大，抗NO性能较好。     

Rate-distortion-complexity optimization for x265

Rate-distortion optimization (RDO) is conventionally based on the analysis of rate-distortion (R-D) curve to minimize the coding distortion under the coding bits constraint. However, it is necessary to consider the computational complexity in the RDO process. In this paper, we obtain the Confidence LEvel - Computational complexity (CLEC) curves which indicate the characteristics of coding tree units (CTUs). Based on the CLEC curves, a rate-distortion-complexity optimization (RDCO) algorithm is proposed to optimize R-D under given computational complexity and achieve the optimal coding performance for x265. Experimental results demonstrate that the proposed algorithm can achieve a wide range of encoding speed under a given quantization parameter (QP) whereas the original x265 can only achieve a few fixed encoding speeds, and the proposed algorithm can reduce the BD-rate and increase the BD-PSNR by 6.59% and 0.13 dB on average under the same requirements of encoding speeds as the original x265.     

A novel intelligent approach for yaw position forecasting in wind energy systems

Yaw control systems orientate the rotor of a wind turbine into the wind direction, optimize the wind power generated by wind turbines and alleviate the mechanical stresses on a wind turbine. Regarding the advantages of yaw control systems, a k-nearest neighbor classifier (k-NN) has been developed in order to forecast the yaw position parameter at 10-min intervals in this study. Air temperature, atmosphere pressure, wind direction, wind speed, rotor speed and wind power parameters are used in 2, 3, 4, 5 and 6-dimensional input spaces. The forecasting model using Manhattan distance metric for k = 3 uncovered the most accurate performance for atmosphere pressure, wind direction, wind speed and rotor speed inputs. However, the forecasting model using Euclidean distance metric for k = 1 brought out the most inconsistent results for atmosphere pressure and wind speed inputs. As a result of multi-tupled analyses, many feasible inferences were achieved for yaw position control systems. In addition, the yaw position forecasting model developed was compared with the persistence model and it surpassed the persistence model significantly in terms of the improvement percent.     

Effective PtAu nanowire network catalysts with ultralow Pt content for formic acid oxidation and methanol oxidation

Pt is the ideal anode catalyst in fuel cells. In this paper, in order to increase the utilization of Pt, the PtAu nanowire networks (NWNs) with ultralow content of Pt are fabricated by a simple silicon monoxide (SiO) reduction method without any capping agent. PtAu NWNs supported on carbon black with Pt content of 1 wt% (Pt₀.₀₅Au NWNs) are employed as catalysts for formic acid oxidation (FAO) and methanol oxidation reaction (MOR), whose mass activities are as high as 4998.9 and 2282.3 mA∙mg_Pt⁻¹, respectively. The network structure facilitates the electron transfer and increases the stability of the catalysts. The PtAu composite experiences compressive lattice strain as confirmed by X-ray powder diffraction (XRD). The Pt₀.₀₅Au NWNs catalyst with low Pt content results in the largest strain variation compared with PtAu composited of other ratios, which may downshift the d-band center of Pt and lead to the higher electrocatalytic activity in oxidation reaction.     

Urban amenities for creativity: An analysis of location drivers for photography studios in Nanjing,China

Urban amenities have been an increasing concern in recent scholarly discussion for their crucial role in promoting local economic development, especially for the rapid rise of the creative class. However, due to the Anglophone dominance in current discourse on this issue, the urban amenities for creativity in the particular context of China remain under-explored. This paper focuses on the location drivers for a specific sector of creative industries, photography studios, based at city level in Nanjing, China. It is suggested that urban amenities for creativity present great power to explain the spatial concentration of photography studios in the old downtown area of Nanjing. In general, photography entrepreneurship is closely associated with landscape amenities, leisure and networking amenities, and accessibility, whereas it is only slightly related to educational amenities. More specifically, the urban amenities for creativity for photography in Nanjing refer in particular to city gardens, cultural heritage, catering places, subway stations, locations which are relatively different from the attractions for creativity that are highlighted by the studies based in West. We therefore propose a contextualized and categorized approach for the urban policy of creative cities.     

Hollow porous nanocuboids cobalt-based metal–organic frameworks with coordination defects as anode for enhanced lithium storage

Journal of Materials Science - Controlling the morphology of metal–organic frameworks to improve their application in energy storage remains a particular challenge. In this work, hollow...