Experimental analysis of particle deposition on single collectors

Experimental studies of particle deposition from liquid suspensions of monodispersed particles flowing past single spherical collectors were carried out and compared with theoretical results based on trajectory calculations. The experimental observations indicate the significant effect of particle flocculation and thus suggest the importance of sedimentation as a collection mechanism. The agreement between the theoretical results and the experimental data is good when the surface force interactions are favorable for collection. However, when the electrokinetic repulsion dominates in the neighborhood of the collector, the rate of collection drops rapidly, although not to zero as predicted by theory.     

Picture-Neutrosophic Trusted Safe Semi-Supervised Fuzzy Clustering for Noisy Data

Clustering is a crucial method for deciphering data structure and producing new information. Due to its significance in revealing fundamental connections between the human brain and events, it is essential to utilize clustering for cognitive research. Dealing with noisy data caused by inaccurate synthesis from several sources or misleading data production processes is one of the most intriguing clustering difficulties. Noisy data can lead to incorrect object recognition and inference. This research aims to innovate a novel clustering approach, named Picture-Neutrosophic Trusted Safe Semi-Supervised Fuzzy Clustering (PNTS3FCM), to solve the clustering problem with noisy data using neutral and refusal degrees in the definition of Picture Fuzzy Set (PFS) and Neutrosophic Set (NS). Our contribution is to propose a new optimization model with four essential components: clustering, outlier removal, safe semi-supervised fuzzy clustering and partitioning with labeled and unlabeled data. The effectiveness and flexibility of the proposed technique are estimated and compared with the state-of-art methods, standard Picture fuzzy clustering (FC-PFS) and Confidence-weighted safe semi-supervised clustering (CS3FCM) on benchmark UCI datasets. The experimental results show that our method is better at least 10/15 datasets than the compared methods in terms of clustering quality and computational time.     

Stationary points of a kurtosis maximization algorithm for blindsignal separation and antenna beamforming

Blind source separation has been the subject of extensive research. In particular, blind antenna beamforming is an effective signal separation technique for communication systems to combat co-channel interference. Among many potential candidate approaches, the simple constant modulus algorithm (CMA) has been widely studied and used in practice. The CMA is designed to capture and separate signals with negative kurtosis. However, when some signals have positive kurtoses, the CMA is unable to capture and separate these sources. We show that the kurtosis maximum algorithm (KMA) can capture signals with both the positive and negative kurtoses. Its global convergence proof is presented for noiseless systems with multiple signals sources and for systems with a single source and zero-kurtosis (such as Gaussian) additive noise     

相图识别与相图的计算机管理系统

本文在建立相图数据库的基础上,提出了一种基于模式识别与模糊概念的相图录入方法。通过图象扫描仪将相图扫入,形成映像(image)文件,再由计算机来自动识别相图,将图中相线上的点以数据形式进行存贮,实现读取数据自动化。本文还介绍了该相图数据库管理系统的功能,并对其进一步的应用给出了实例。     

Finite-difference time-domain simulations of the effects of air gaps in double-shell extended hemispherical lenses

The effects of parasitic air gaps on the input impedance and radiation characteristics of dense double-shell integrated lens antennas are studied numerically at millimetre waves using the finite-difference time-domain method. The lens core is made up of Macor or silicon, and is coated with a quarter wavelength matching layer. Two kinds of gaps are compared: they are located either (i) between both shells of the lens, or (ii) between the lens base and the feed substrate. We show that their impact is much more critical in the second case, and that it becomes dramatic for silicon lenses, even with very thin gaps (smaller than ? ₀/100); the three major observed effects are the following: (i) strong shift of the resonant frequency, (ii) beam broadening and directivity loss, (iii) increase of the side lobe level.     

Foreign Particle Promoted Crystalline Nucleation for Growing High‐Quality Ultrathin Rubrene Films

Introducing foreign particles or agents as nucleator is an efficient way to promote crystallization in the crystal growth field, with the advantage to speed up the crystallizing rate and control the growth process. However, in the field of organic crystalline film growth, where the crystallization and morphology modulation are of significant importance in optoelectronics, this method has rarely been utilized. Particularly, some potential high‐performance materials such as rubrene face the problem of crystallization during film formation. Here a strategy is reported to promote the crystallization of rubrene films in the initial stage assisted by foreign particles. Highly ordered thin film from the sub‐monolayer stage can be achieved. Efficient charge transport and high mobility up to 2.95 cm² V^?1 s^?1 are achieved on thus ultrathin crystalline films. Such a method enables the well controlling of the film growth from the very early stage and produces uniform crystalline films with good reproducibility, thus highly promising to yield desired optoelectrical properties and applications.     

周期极化钽酸锂倍频窄谱线全光纤连续激光放大器特性

通过准相位匹配技术,采用1μm波段高功率窄谱线连续光纤激光放大器抽运高二次谐波转换效率周期性极化晶体,是实现高光束质量、小型化、高功率连续绿光激光器的一个非常有前途的方向。实验自主研发了高效率主振荡功率放大(MOPA)全光纤保偏放大模块,获得中心波长为1064.25nm,线宽为0.035nm的30 W连续线偏振激光,并以此作为基频光抽运国产周期极化钽酸锂(PPSLT)晶体进行了外腔单通倍频实验。保持PPSLT晶体的控制温度为145.6℃,在抽运光功率为21.5W时得到了2.1W的绿光输出。实验分析了温度、基频光功率密度和Boyd-Kleinman聚焦因子对倍频光转换效率的影响。实验过程中没有出现饱和现象,进一步提高抽运功率有望获得更高功率的绿光。     

Recent Advances on 3D Printing Technique for Thermal‐Related Applications

Advances in ink formulation and printing techniques make producing material systems with new and versatile characteristics and functionalities possible. Additive manufacturing or 3D printing enables fabricating complex structures at a faster production rate using different types of materials for various applications. Recently, 3D printing methods are being studied for thermal‐related applications. In this paper, the authors review recent progress of materials and printing techniques for thermal application devices using composite materials.

     

Quantitative studies by differential scanning calorimetry of the reaction between hydrogen peroxide and lignocellulose

Heat of reaction and kinetic parameters were determined by differential scanning calorimetry for decomposition of hydrogen peroxide, reaction of hydrogen peroxide with lignocellulosic materials, glucose and pinitol, and for the reaction of the same materials with produced or introduced oxygen. The heat of decomposition of hydrogen peroxide obtained in N₂ (720 cal/g H₂O₂) was in fair agreement with literature data, considering the different temperature and pressure conditions. The heats of reaction of hydrogen peroxide and lignocelluloses were higher when determined in N₂ (1670–2500 cal/g H₂O₂) than in O₂ (1450–2020 cal/g H₂O₂) atmosphere. The activation energy for decomposition of hydrogen peroxide amounted to 20.3 kcal/mol in N₂ and 15.9 kcal/mol in O₂ with frequency factors of 5.7 × 10⁹ and 3.7 × 10⁷ min^?1, respectively. The activation energies for the reaction of hydrogen peroxide and lignocellulosic materials tested were similar and not influenced by the atmospheric composition, ranging overall between 19.7 and 22.4 kcal/mol. The corresponding frequency factors ranged between 2.77 × 10⁹ and 2.23 × 10¹¹.     

纳米VO2的制备及在智能控温包装材料中的应用

本文分别采用水热法和溶剂热法制备低维VO₂（B）纳米材料,然后在N₂（99.999%）氛围中将VO₂（B）进行623K热处理,得到VO₂（M）蓝黑色粉末。利用X-射线衍射（XRD）、X-射线光电子能谱（XPS）、红外光谱（FTIR）、透射电子显微镜（T。EM）和高分辨力透射电子显微镜（HRTEM）等测试样品的成分及形貌特征。结果发现:水热法制得的VO₂（B）经热处理后得到VO₂（M）纳米带,该纳米带有数微米长,宽100～150nm,厚20～30nm,是典型的纳米带状结构;溶剂热法制得的VO₂（B）经热处理后得到花瓣状纳米团簇的VO₂（M）,该花瓣状团簇纳米材料由超薄薄片组装而成,长短不均,宽约数10nm。将VO₂（M）纳米粉体、高分子分散剂和硅树脂混合制备得到智能控温包装材料（ICTPM）;通过变温红外测试,发现以水热法和溶剂热法所制备的VO₂（M）为基础的包装材料的相变温度为341K,这一结果为VO₂（M）在智能控温包装中的应用奠定了基础。