The overall crystallization behavior of polyethylene/wax blends as phase change materials for thermal energy storage: A mini review

This review paper deals with the overall crystallization behavior of polyethylene/wax blends as phase change materials (PCMs) for thermal energy storage with the determination of their thermal properties. The addition of molten wax to the polyethylenes decreases the crystallization and melting temperatures of the blends. However, incorporating fillers to the polyethylene/wax blends can either decrease or increase the crystallization and melting temperatures of the composites depending on the filler type. The normalized enthalpy values of linear low-density polyethylene showed no significant change when increasing the wax content. On the contrary, the normalized enthalpy values of the wax in the blends were lesser than that of pure wax and increased with increasing wax content. Since the wax in the blend had a lower crystallinity compared to pure wax, this influences its effectiveness as a PCM for thermal energy storage. The effect of different polyethylenes on the wax morphology gave rise to enhance phase separation when wax was blended to high-density polyethylene as compared to the other polyethylenes. On the contrary, the effect of various waxes on the morphology of polyethylene resulted in different morphologies due to the molecular weight of the wax used and the structure of the polyethylene chain. The addition of fillers to the polyethylene (PE)/wax samples resulted in enhanced phase separation. The overall isothermal crystallization rate and the equilibrium melting temperature of PEs in the PEs/wax blends were depressed by wax addition due to the wax dilution effect.     

Synthesis and Initial Characterization of a Selective,Pseudo-irreversible Inhibitor of Human Butyrylcholinesterase as PET Tracer

The enzyme butyrylcholinesterase (BChE) represents a promising target for imaging probes to potentially enable early diagnosis of neurodegenerative diseases like Alzheimer's disease (AD) and to monitor disease progression in some forms of cancer. In this study, we present the design, facile synthesis, in vitro and preliminary ex vivo and in vivo evaluation of a morpholine-based, selective inhibitor of human BChE as a positron emission tomography (PET) tracer with a pseudo-irreversible binding mode. We demonstrate a novel protecting group strategy for ¹⁸F radiolabeling of carbamate precursors and show that the inhibitory potency as well as kinetic properties of our unlabeled reference compound were retained in comparison to the parent compound. In particular, the prolonged duration of enzyme inhibition of such a morpholinocarbamate motivated us to design a PET tracer, possibly enabling a precise mapping of BChE distribution.     

AP2M1 Supports TGF-β Signals to Promote Collagen Expression by Inhibiting Caveolin Expression

The extracellular matrix (ECM) is important for normal development and disease states, including inflammation and fibrosis. To understand the complex regulation of ECM, we performed a suppressor screening using Caenorhabditis elegans expressing the mutant ROL-6 collagen protein. One cuticle mutant has a mutation in dpy-23 that encodes the μ2 adaptin (AP2M1) of clathrin-associated protein complex II (AP-2). The subsequent suppressor screening for dpy-23 revealed the lon-2 mutation. LON-2 functions to regulate body size through negative regulation of the tumor growth factor-beta (TGF-β) signaling pathway responsible for ECM production. RNA-seq analysis showed a dominant change in the expression of collagen genes and cuticle components. We noted an increase in the cav-1 gene encoding caveolin-1, which functions in clathrin-independent endocytosis. By knockdown of cav-1, the reduced TGF-β signal was significantly restored in the dpy-23 mutant. In conclusion, the dpy-23 mutation upregulated cav-1 expression in the hypodermis, and increased CAV-1 resulted in a decrease of TβRI. Finally, the reduction of collagen expression including rol-6 by the reduced TGF-β signal influenced the cuticle formation of the dpy-23 mutant. These findings could help us to understand the complex process of ECM regulation in organism development and disease conditions.     

基于多特征融合的电影推荐系统

协同过滤算法（CF）根据用户-物品的评分矩阵做推荐，未考虑物品自身属性。本文将MovieLens数据集上的电影属性，作为影响推荐结果的因素，融合电影的简介、评论、评分、导演和演员等多种因素，进行推荐。使用CNN（卷积神经网络）和Word2Vec（Word to Vector,词向量模型）处理电影简介；使用AFINN（Finn rup Nielsen情感词典）处理评论，并对结果进行映射；对导演和演员数据进行建模，得到该因素下的预测评分，最后将各因素下的结果进行加权融合，通过调整权重，得到最佳效果。经验证，该方法的推荐性能优于传统的CF算法。     

凝胶型99Mo-99mTc发生器研究现状

与裂变型⁹⁹Mo-^99mTc发生器相比，凝胶型⁹⁹Mo-^99mTc发生器制备^99mTc具有工艺简单、产生的放射性废物容易处理、对环境影响小等优点。本文主要论述了凝胶型⁹⁹Mo-^99mTc发生器与裂变型⁹⁹Mo-99mTc发生器的区别，堆照生产⁹⁹Mo原料和凝胶材料的研究进展，凝胶结构以及凝胶组分等多种条件因素对凝胶型⁹⁹Mo-^99mTc发生器性能的影响等，并对低比活度⁹⁹Mo生产^99mTc的研究进展进行综述。     

Evaluation of adult and offspring thiamine deficiency in salmonine species from Lake Ontario

Thiamine Deficiency Complex (TDC) is an ongoing problem impacting salmonine health in various waterbodies, including Lake Ontario. The prevalence of TDC has been variable and explanations for differences are limited. In the current study, thiamine concentrations were measured in eggs, liver tissue, and muscle tissue sampled from brown trout (Salmo trutta), Chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), lake trout (Salvelinus namaycush), and steelhead trout (O. mykiss) that were collected from Lake Ontario and its surrounding tributaries. The occurrence of TDC was measured for each species based on TDC-induced offspring mortality rates under laboratory conditions. TDC-induced offspring mortality was observed for all species except brown trout. For affected species, egg free thiamine (Th) was consistently low compared to lake trout collected from Lake Superior that are considered thiamine replete. In addition, species with the lowest percentages of Th in their eggs were the most susceptible to TDC, suggesting that limited thiamine reserves in the form of Th may cause TDC-induced offspring mortality. Lastly, our results show that egg thiamine concentrations have yearly variation and increased for all species throughout the study. Reasons for such variation are undetermined; but, if egg thiamine concentrations continue to increase, the impacts of TDC on these salmonine species may lessen. Future monitoring is needed for determining if thiamine concentrations are increasing and the potential impacts that may have on the entire Lake Ontario fishery.     

基于改进耦合增强随机共振的滚动轴承故障诊断

针对强背景噪声下经典随机共振方法对滚动轴承故障特征提取效果差的问题,提出了一种基于改进耦合增强随机共振的滚动轴承故障诊断方法。首先,利用一个定参双稳系统和一个变参双稳系统构成耦合随机共振系统,外部输入直接作用于定参双稳系统;然后,通过调节变参双稳系统参数和耦合系数实现耦合系统的随机共振控制,并借助遗传算法实现控制参数的自适应选取。实验和工程应用验证了所提方法的有效性和优越性。     

Numerical modelling of a low power non-transferred arc plasma reactor for methane conversion

Thermal flow characteristics and the methane conversion reaction in a low power arc plasma reactor for efficient storage and transport of methane, which is the main component of shale gas, were simulated. The temperature and velocity distributions were calculated according to the type of discharge gases and arc current level by a self-developed magnetohydrodynamics (MHD) code and a commercial ANSYS-FLUENT code; the transport of chemical species was analyzed as including the chemical reactions of methane conversion. The simulated results were verified by the comparison of calculated and measured arc voltages with permissible low error as under 4%. Three C₂ hydrocarbon gases with ethane (C₂H₆), ethylene (C₂H₄), and acetylene (C₂H₂) were selected as the converted species of methane from experimental data. The mass fraction of C₂ hydrocarbons and hydrogen as the product of the conversion reaction at the reactor was also calculated. Those values show good agreement with the actual experimental results in that the major conversion reaction occurred in C₂H₂ and hydrogen, and the conversions to C₂H₆, C₂H₄, and hydrogen were minor reactions of methane pyrolysis conversion.     

Effect of preparation method on physicochemical properties and catalytic performances of LaCoO_3 perovskite for CO oxidation

Perovskite oxides LaCoO_3 prepared by templating, co-precipitation and sol-gel method with different complexants were systematically characterized and its catalytic performances for CO oxidation were investigated. The samples were characterized by X-ray diffraction, thermogravimetry analysis and differential scanning calorimetry, N_2 physisorption, transmission electron microscopy, temperature program reduction of hydrogen, temperature program desorption of oxygen and X-ray photoelectron spectroscopy measurement, results of which show that the properties of LaCoO_3, such as surface morphology, surface area, surface compositions, redox capability, oxygen vacancy, as well as the calcination temperature and formation mechanism, depend intimately on the preparation method. Catalytic tests indicate that the sample prepared by carbon templating method shows the best activity for CO oxidation, with full CO conversion obtained at 135 ℃. In particular, the catalyst can be activated and significant increase of activity can be obtained with the increase of reaction time. The cyclic and longterm stability of catalysts were discussed and compared.     

An improved cuckoo search algorithm for the problem of electric distribution network reconfiguration

Power loss reduction has an important role in operating electric distribution network system. There are a lot of methods for reduction power loss such as capacitor placement, distributed generation placement and electric distribution network reconfiguration (EDNR). Among these methods, the EDNR is an efficient technique to reduce power loss due to without taking any costs. However, the EDNR problem is a nonlinear, discrete problem and lots of extreme points. Therefore, it is necessary to have efficient methods for solving the EDNR problem. In this paper, an improved cuckoo search algorithm (ICSA) is proposed for solving the EDNR problem. In which, based on disadvantages of exploration and exploitation process of cuckoo search algorithm (CSA) for solving the EDNR problem, a local search mechanism is added to exploit candidate solutions existing around the current best solution. The calculated results on the simple distribution networks to complex distribution networks show that ICSA has ability for finding the global optimal solution with much smaller iterations and better quality of obtained solution compared with CSA and some other improved versions of CSA. The performance comparisons with other existing methods available in previous studies and the software of Power System Simulator/Advanced Distribution Engineering Productivity Tool (PSS/ADEPT) also lead to the better electric distribution network configuration with smaller total power losses. As a result, ICSA is a potential and reliable method for solving the EDNR problems.