Advances in neutron imaging

Imaging techniques based on neutron beams are rapidly developing and have become versatile non-destructive analyzing tools in many research fields. Due to their intrinsic properties, neutrons differ strongly from electrons, protons or X-rays in terms of their interaction with matter: they penetrate deeply into most common metallic materials while they have a high sensitivity to light elements such as hydrogen, hydrogenous substances, or lithium. This makes neutrons perfectly suited probes for research on materials that are used for energy storage and conversion, e.g., batteries, hydrogen storage, fuel cells, etc. Moreover, their wave properties can be exploited to perform diffraction, phase-contrast and dark-field imaging experiments. Their magnetic moment allows for resolving magnetic properties in bulk samples. This review will focus on recent applications of neutron imaging techniques in both materials research and fundamental science illustrated by examples selected from different areas.     

Investigation on the anti-reduction mechanism of Ti4+ in high dielectric constant system Ca0.9La0.067TiO3 by doping with Al2O3

Ca_0.9La_0.067TiO₃ (abbreviated as CLT) ceramics doped with different amount of Al₂O₃ were prepared via the solid state reaction method. The anti-reduction mechanism of Ti⁴⁺ in CLT ceramics was carefully investigated. X-ray diffraction (XRD) was used to analyze the phase composition and lattice structure. Meanwhile, the Rietveld method was taken to calculate the lattice parameters. X-ray photoelectron spectroscopy (XPS) was employed to study the valence variation of Ti ions in CLT ceramics without and with Al₂O₃. The results showed that Al³⁺ substituted for Ti⁴⁺ to form solid solution and the solid solubility limit of Al³⁺ is near 1.11 mol%. Furthermore, the reduction of Ti⁴⁺ in CLT ceramics was restrained by acceptor doping process and the Q × f values of CLT ceramics were improved significantly. The CLT ceramic doped with 1.11 mol% Al₂O₃ exhibited good microwave dielectric properties: ε_r = 141, Q × f = 6848 GHz, τ_f = 576 ppm/°C.     

Delineation of mineral potential zone using high resolution aeromagnetic data over part of Nasarawa State,North Central,Nigeria

Qualitative analysis of aeromagnetic data of part of Nasarawa State had been carried out with the aim of delineating mineral potential zone. The study area is bounded by Longitude 8.0°E – 9.0°E and Latitude 8.0°N – 9.5°N with an estimated total area of 18,150?km². Different filters were used to enhance the short wavelength anomalies which could give preliminary information about the magnetic minerals present in the study area. The total magnetic intensity map shows variation of both highs and lows magnetic signature ranges from ?51.2?nT to 110.4?nT after the removal of IGRF value of 33,000?nT; the highs which is basement dominates the north-eastern and north-western part of the study area which corresponds to Akwanga, Wamba and Nasarawa Eggon; these are areas with promising solid minerals of economic potentials like, gold at Wamba; Tin, Columbite and Tantalite at Akwanga while Granite rocks with possible radioactive elements are in abundance at Nasarawa Eggon. The low magnetic values on the other hand, which is made up of sediment deposition also dominates the southern part of the study area, this area corresponds to Lafia, Doma and Keana; Lafia and Doma host some industrial minerals like Clay, glass Sands and the Salt Brines at Keana. The major high magnetic signature trends east-west. The greenish part of the study area indicates alluvium deposition. The filters used are vertical derivatives, downward continuation and analytic signal. The first and second vertical derivatives; shows structures like lineament that could be the host to minerals present in the study area and it trends NE-SW. The downward continued at the depth of 50?m and 100?m shows the veins where magnetic minerals most especially gold are known to settle along igneous and metamorphic rocks. The analytic signal map shows that magnetic amplitude highs could be found at the northern end with most lineaments delineated also conform to other filter used. The tilt derivative map enhances short wavelength anomalies which could be used to mapped shallow basement structures and mineral exploration targets. The results of these filters agreed largely and since most magnetic minerals are structural controls, it is expected that those lineaments identified, most especially at the northern part, could play host to those minerals aforementioned.     

小尺度交通信号灯的检测与状态识别

交通信号灯识别包括检测和状态识别，在智能交通系统中发挥重要作用。基于YOLOv3算法提出了一种交通信号灯检测与状态识别模型。针对交通信号灯相较于交通场景中其他目标具有尺度小的特性进行了算法的设计：降低骨干网络的下采样倍率以增加小尺度目标的特征描述能力；通过增大特征图的尺度来改进多尺度特征融合；引入广义交并比作为检测任务的损失函数来改进目标边界框的回归效果。同时，根据交通信号灯本身的特性，使用颜色和形状约束的方法对信号灯进行状态识别和类别验证。最后在公开的Bosch交通信号灯数据集上和实际的城区道路进行了实验验证。实验结果表明，所提出的算法能够提升交通信号灯识别的精度和召回率，识别准确率可以达到90%左右。     

Effect of ultrasonication treatment and fermentation by probiotic Lactobacillus plantarum strains on goat milk bioactivities

In the present research, the effects of continuous ultrasound treatment (100 W, 30 kHz; 0%, 30%, 60% and 90% amplitudes, 15 min) and fermentation process (37°C, 24 h) on the growth of Lactobacillus plantarum LP3 and LU5 strains and bioactive properties (peptide content, α-amylase and α-glucosidase inhibition, anticancer and antioxidant activities and exopolysaccharide content) of goat milk were investigated. According to our results, the ultrasonication of milk up to 60% amplitude promoted the growth of Lactobacillus strains and enhanced the bioactive properties compared with control during fermentation, while, the ultrasonication at 90% amplitude had negative effects on the mentioned parameters. Exopolysaccharide content, α-amylase inhibition, α-glucosidase inhibition, antioxidant activity and anticancer activity of treated samples at 60% amplitude at the end of fermentation in comparison to its beginning were increased 18.09, 12.79, 12.44, 9.4 and 1.92 folds, respectively. Also, the increase of assayed characteristics was found strain-dependent, so that L. plantarum LP3 was more effective than LU5 strain.     

基于双层修正无迹卡尔曼的水下节点定位算法* .txt

摘要：针对水下无线传感网络中运动节点定位精度低的问题，提出了一种新的基于双层修正无迹卡尔曼的水下节点定位算法(DLMUKF)。该算法利用下层无迹卡尔曼滤波算法对节点状态进行预测，根据各信标节点的测距传播时延对预测的节点状态进行修正。运用上层无迹卡尔曼滤波算法对修正后的状态进行新的预测与修正。仿真实验中，DLMUKF算法的平均定位误差约为传统多边定位算法的15%，约为基于无迹卡尔曼滤波（UKF）定位算法的16%，受节点运动时间与速度的影响最小。通过实验证明DLMUKF算法能更充分利用实际距离值，可以有效减小运动节点的定位误差。 .txt     

Fabrication of highly sensitive MnO2/F-MWCNT/Ta hybrid nanocomposite sensor with different MnO2 overlayer thickness for H2O2 detection

In this work, we report the development of MnO₂/F-MWCNT/Ta hybrid nanocomposite sensor with different MnO₂ overlayer thickness for the detection of H₂O₂ in real samples. A novel two-step process using e-beam evaporation and spray pyrolysis deposition was adopted for the synthesis of hybrid MnO₂/F-MWCNT/Ta electrodes. SE morphology revealed smaller-sized, compact grains of MnO₂ infiltrated on the outermost walls of MWCNTs. Raman analysis confirmed the existence of carbon nanotubes with abundant structural defects of MnO₂ in the composite. The cyclic voltammetry results displayed a high peak current and narrowed over potential towards the reduction of H₂O₂. The sensor displayed a fast response (<5?s), wide linear range (2–1510?μM) and a low limit of detection (0.04?μM) with significant anti-interfering properties, promising for the development of highly sensitive and reproducible biosensors. The three dimensional nanocomposite sensor also exhibited good recovery (> 98%), thus providing a favourable tool for analysis of H₂O₂ in milk samples.     

Milk from cows fed a diet with a high forage:concentrate ratio improves inflammatory state,oxidative stress,and mitochondrial function in rats

Excessive energy intake may evoke complex biochemical processes characterized by inflammation, oxidative stress, and impairment of mitochondrial function that represent the main factors underlying noncommunicable diseases. Because cow milk is widely used for human nutrition and in food industry processing, the nutritional quality of milk is of special interest with respect to human health. In our study, we analyzed milk produced by dairy cows fed a diet characterized by a high forage:concentrate ratio (high forage milk, HFM). In view of the low n-6:n-3 ratio and high content of conjugated linoleic acid of HFM, we studied the effects of this milk on lipid metabolism, inflammation, mitochondrial function, and oxidative stress in a rat model. To this end, we supplemented for 4 wk the diet of male Wistar rats with HFM and with an isocaloric amount (82 kJ, 22 mL/d) of milk obtained from cows fed a diet with low forage:concentrate ratio, and analyzed the metabolic parameters of the animals. Our results indicate that HFM may positively affect lipid metabolism, leptin:adiponectin ratio, inflammation, mitochondrial function, and oxidative stress, providing the first evidence of the beneficial effects of HFM on rat metabolism.     

一种下肢运动意图识别算法性能实时测评系统* .txt

摘要：对腿部运动意图识别算法的实时性能进行综合可靠的评价是实现下肢假肢灵活稳定控制的前提。提出一种逐层分级的基于下肢运动意图识别算法的实时测评方法，对算法的可靠性、稳定性以及运动意图识别速度进行综合评价。利用开发的运动意图识别算法评测系统，对基于肌电信号源和机械信号源的两种运动意图识别算法进行了实时性能测试，发现肌电信号源的算法识别时间大于机械信号源算法，但是其算法稳定性优于机械信号源算法。进一步地，还利用该评测系统有效地区分出正常识别策略与异常识别策略，发现正常策略的动作识别稳定系数比异常策略高25%左右。因此，所提的基于下肢运动意图识别算法的实时测评方法，能够对不同信号源算法以及不同识别策略的实时性能进行有效评价，为智能下肢假肢控制系统开发提供可供参考的测试平台。 .txt