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《Ceramics International》2022,48(11):15056-15063
Hydrogen (H2) sensors based on metal oxide semiconductors (MOS) are promising for many applications such as a rocket propellant, industrial gas and the safety of storage. However, poor selectivity at low analyte concentrations, and independent response on high humidity limit the practical applications. Herein, we designed rGO-wrapped SnO2–Pd porous hollow spheres composite (SnO2–Pd@rGO) for high performance H2 sensor. The porous hollow structure was from the carbon sphere template. The rGO wrapping was via self-assembly of GO on SnO2-based spheres with subsequent thermal reduction in H2 ambient. This sensor exhibited excellently selective H2 sensing performances at 390 °C, linear response over a broad concentration range (0.1–1000 ppm) with recovery time of only 3 s, a high response of ~8 to 0.1 ppm H2 in a minute, and acceptable stability under high humidity conditions (e. g. 80%). The calculated detection limit of 16.5 ppb opened up the possibility of trace H2 monitoring. Furthermore, this sensor demonstrated certain response to H2 at the minimum concentration of 50 ppm at 130 °C. These performances mainly benefited from the special hollow porous structure with abundant heterojunctions, the catalysis of the doped-PdOx, the relative hydrophobic surface from rGO, and the deoxygenation after H2 reduction. 相似文献
3.
Smartphones are indispensable for many young people, which in turn increases the risk of smartphone addiction. Previous studies have discovered significant and positive influences of boredom proneness, sensation seeking and smartphone addiction. This study further explored these influences, their underlying mechanisms, and the mediating effects of pastime, flow experience and self-regulation on smartphone addiction. A total of 442 Chinese college students completed a survey focusing on boredom proneness, sensation seeking, pastime, flow experience, self-regulation and smartphone addiction. The results indicated that boredom proneness positively affects smartphone addiction. Contrary to expectations, the results showed that there is no significant relationship between sensation seeking and smartphone addiction. Moreover, pastime and self-regulation have partial mediation effects on the relationship between boredom proneness and smartphone addiction, while the effect of sensation seeking on smartphone addiction is completely transmitted with the help of flow experience and self-regulation. The findings and their implications are discussed. 相似文献
4.
As a response to the threat of climate change, many nations are increasing their use of renewable energy, including wind energy. Large wind farms often conflict with other land uses, particularly tourism, which is a growing industry worldwide. In Iceland, tourism has recently become the largest export sector, with majority of tourists travelling to the country to experience its nature. This paper examines tourists’ opinions and perceptions of wind power development in the Southern Highlands of Iceland and compares how number, size and proximity of wind turbines, and the landscape in which they are situated, influence tourists’ perceptions. The study is based on an on-site questionnaire survey conducted in 2015. The results indicate that one-third of the travellers would be less likely to visit the Southern Highlands if a proposed wind farm were built, and two-thirds think that wind turbines would decrease the area’s attractiveness. 相似文献
5.
Pradum Pundlikrao Ige Rohit Ravindra Badgujar Pankaj Padmakar Nerkar Hitendra Shaligram Mahajan Raju Onkar Sonawane Sanjay Javarilal Surana 《Particulate Science and Technology》2018,36(5):583-591
Drug which shows extensive first pass effect is difficult task that, needs to be solved by formulators in the pharmaceutical science. The low oral bioavailability (49%) of flutamide may be due to poor wettability, low aqueous solubility and extensive first pass effect. The aim of present investigation was to prepare flutamide loaded microspheres and incorporate it into suppositories for rectal delivery to avoid first pass effect and enhance residence time. Flutamide loaded mucoadhesive microspheres of Ocimum Basilicum mucilage (OBM) were prepared using spray drying and characterized by percent production yield, encapsulation efficiency, particle size, zeta potential, polydispersity index, DSC, SEM, XRPD, in vitro drug release and stability studies. Moreover, ex vivo mucoadhesion was investigated using falling liquid film technique to determine the adhesion of microspheres to sheep rectal mucosa. The microspheres had nearly spherical shape and size about 2.53?μm. The encapsulation efficiency and mucoadhesion of optimized formulation MBF10 were found to be 69.6?±?2.3% and 89.01?±?2.18%, respectively. Percent CDR of optimized flutamide loaded mucoadhesive microspheres was found to be 88.7?±?1.3 at 7?h. In conclusion, OBM microparticles based suppository could be used to deliver drug through rectal delivery. 相似文献
6.
《Advanced Powder Technology》2020,31(1):287-299
The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed. 相似文献
7.
探讨沉浸式艺术这一新概念,研究其审美体验是如何有助于自我发现并运用于艺术创作再设计中的。沉浸式艺术是一种能够启发感知联觉的审美体验方式,可使人们重新思考自己与“世界”(真实和虚拟)之间的关系。“感知”、“关系”和“转换”是三个相互交织并贯穿全文的主要问题,同时也是沉浸式艺术的研究基础。结合海德格尔“在世界上”(être-au-monde) 的观念来看,与其说“存在”,不如说人们沉浸并感知于这个世界中。然而,人们对周围环境的感知通常是无意识的,对于感知的认识也时常是冷漠和忽视的。沉浸式艺术使这些感觉得以被强调,它突出了个人的感知运动能力,同时也引起了人们对身体本身的重视。又如Bergson所提出的“投机性关注是建立在一种感知机制的基础上的,这种感知机制从根本上允许对世界进行一定行动而不是仅仅了解这个世界”。因此,对于一个完善的沉浸式审美体验过程来说,重要的是使观众自然地参与其中。当无意识的行为转换为肉眼可见的视觉效果时,审美体验将会更加深入人心。因此关于沉浸式艺术作品的创作,可以结合西方艺术家Marcel Duchamp的Ready-made的创作理念和中国道家的“无为”思想,研究怎样将被忽视的日常行为自然地转换为可见的,被重视的视觉效果,从而揭发主体与“世界”之间的多种潜在关系。 相似文献
8.
为解决无线基站宽带工作频带内电压驻波比(Voltage Standing Wave Ratio,VSWR)的实时测量,提出了一种采用信道估计法的测量方案。该方案实现简单,在基带处理单元高速率位置发送数据,依次抓取射频通道反馈和反射数据,分别求取信道响应序列,结合工厂装备测试数据,计算驻波反射系数和反射点位置。发送信号采用宽带正交频分复用信号,能检测到工作频段内任何频点处的驻波异常。有用信号前加循环前缀,并引入峰值抵消核,能正确检测到多个反射点驻波。仿真结果表明,该方案驻波测量精度和单回波点位置精度达到预期,多回波点测量能抓准外部主要故障点,在基站VSWR实时测量中具有良好的应用前景。 相似文献
9.
为了更加有效地检索到符合用户复杂语义需求的图像,提出一种基于文本描述与语义相关性分析的图像检索算法。该方法将图像检索分为两步:基于文本语义相关性分析的图像检索和基于SIFT特征的相似图像扩展检索。根据自然语言处理技术分析得到用户文本需求中的关键词及其语义关联,在选定图像库中通过语义相关性分析得到“种子”图像;接下来在图像扩展检索中,采用基于SIFT特征的相似图像检索,利用之前得到的“种子”图像作为查询条件,在网络图像库中进行扩展检索,并在结果集上根据两次检索的图像相似度进行排序输出,最终得到更加丰富有效的图像检索结果。为了证明算法的有效性,在标准数据集Corel5K和网络数据集Deriantart8K上完成了多组实验,实验结果证明该方法能够得到较为精确地符合用户语义要求的图像检索结果,并且通过扩展算法可以得到更加丰富的检索结果。 相似文献
10.
The visual ability factors of peripheral perception, visual reaction and visual pursuit ability are important for safe driving. Thus, this study explored the influence of driving experience on these visual ability factors. Sixty-five drivers, including novice and experienced drivers, participated in this study. The visual ability levels of the three factors were measured by the Vienna Test System. In addition, driver's awareness of the three factors' importance for safe driving was measured by questionnaire items. Results showed that out of the three factors, drivers' peripheral perception ability was correlated significantly with their driving experience. Experienced drivers had higher peripheral perception ability than that of novice drivers. In addition, compared with novice drivers, experienced drivers believed that peripheral perception was more important whereas visual reaction was less important. It is suggested that higher attention should be paid to peripheral perception in driving training and novice drivers should increase their importance awareness for this factor. 相似文献