遗传算法结合响应面法优化番茄红素纳米结构脂质载体的制备

目的 提高脂溶性番茄红素的生物利用率和稳定性。方法 采用熔融-高速剪切法制备番茄红素纳米结构脂质载体。以包封率、平均粒径为主要评价指标，进行单因素实验，并在单因素基础上通过遗传算法结合Box-Behnken响应面法对制备工艺进行优化。结果 遗传算法和Box-Behnken响应面法优化得到的理论包封率分别为86.208 2%、86.169 5%。通过验证实验得到实际包封率为(86.267±0.44)%，平均粒径为(121.8±5.20)nm。结论 结果表明遗传算法结合Box-Behnken响应面法优化番茄红素纳米结构脂质载体模型可靠。     

甜玉米芯多糖对胰岛素抵抗HepG2细胞糖代谢功能的影响

目的：探讨甜玉米芯多糖（sweet corncob polysaccharide，SCP）组分SCP-80-I对胰岛素抵抗HepG2（insulin resistant HepG2，IR-HepG2）细胞糖代谢功能的影响。方法：确立IR-HepG2细胞模型建立的最佳条件，并由此建立IR-HepG2细胞模型；分别以50、100、200、400 μg/mL剂量的SCP-80-I孵育细胞24 h，评价其对细胞葡萄糖消耗的影响，同时利用噻唑蓝法评价其细胞毒性；检测氧化应激标志物超氧化物歧化酶（superoxide dismutase，SOD）、丙二醛（malondialdehyde，MDA）及活性氧（reactive oxygen species，ROS）的水平，测定细胞内糖原积累水平及糖酵解关键限速酶己糖激酶（hexokinase，HK）、丙酮酸激酶（pyruvate kinase，PK）的活力。结果：确立以1×10－6 mol/L胰岛素处理24 h作为诱导IR-HepG2细胞形成的最佳条件，并成功建立IR-HepG2细胞模型；在孵育实验中，SCP-80-I能极显著增加IR-HepG2细胞的葡萄糖摄取量（P＜0.01），细胞活力随SCP-80-I质量浓度的增加呈先上升后下降的趋势；200 μg/mL SCP-80-I处理组与模型对照组相比，胞内MDA含量极显著下降，SOD活力极显著提高，ROS水平极显著下降（P＜0.01）；胞内糖原含量极显著增加（P＜0.01），HK与PK活力极显著增加（P＜0.01）。结论：推测SCP-80-I的降血糖功效与其缓解氧化应激所造成的肝脏细胞损伤，改善胰岛素抵抗肝脏细胞的糖代谢功能有关。     

Infrared Image Segmentation Algorithm Based on Multi Structure Morphology—Pulse Coupled Neural Network in Application to the Inspection of Aerospace Materials

Russian Journal of Nondestructive Testing - Infrared images of aerospace materials were collected by infrared camera and analyzed to evaluate debonding defects. However, it is difficult to identify...     

Dynamic thermal tomography: Recent improvements and applications

The concept of “dynamic thermal tomography” (DTT) was suggested in the 1980s. At that time, there was a wave of interest in the tomographic analysis of materials by active thermal nondestructive testing (TNDT). Unlike particles and quanta of electromagnetic radiation, thermal energy propagates in solids by diffusion. Therefore, a purely geometrical approach, that is characteristic of computed X-ray tomography, is replaced in DTT with the analysis of the evolution of temperature versus time. DTT is based on the fact that, in one-sided TNDT, deeper material layers are characterized by longer time delays of the thermal response. The DTT algorithm is relatively stable when used in the inspection of certain materials. Thermal waves experience damping by amplitude and retardation in time. This limits the detection depth and produces certain artifacts that can be suppressed by thresholding maxigrams. DTT can also be considered as a specific way of data presentation that has proven to be useful in many practical cases, including surface and volumetric thermal stimulation of both metals and non-metals. Thermal tomograms appear similar to binary maps of defects, thus enabling more reliable defect detection in comparison to conventional IR thermograms. In this paper, a “reference-free” approach to DTT is proposed being based on some mathematical manipulations with a front-surface temperature response. Also, the possibility of using the DTT principles for processing the results of ultrasonic infrared thermography is demonstrated.     

Effects of plasma treatments applied to fresh ricotta cheese

The aim of this study was to test two different innovative plasma assisted approaches to prolong ricotta shelf life. In one test the ricotta cheese is directly exposed to the plasma effects, and in the other one the plasma is indirectly applied (i.e. blowing the plasma effluents on the substrate). This last approach is innovative and very promising because in this way, plasma treatment can be assured at moments or at places where no plasma source can be used or is available. To the aim, treated and untreated samples were stored at 4 °C for a period of 8 days, during which microbiological, sensory analyses and pH measurements were carried out. Tests were repeated more times to also taken into account product variability. Results highlighted that both treatments in all tests were effective to control microbial proliferation and preserve sensory quality. Specifically, a significant shelf life prolongation was recorded, ranging between 50% and 100%, depending to the type of treatment and on the initial microbial contamination.Industrial relevanceBoth direct and indirect plasma treatments tested have led to a shelf life increase of up 2 days, which is a very promising result for a fresh product such as artisanal ricotta. The current paper offers the first example in literature of “gentle” and efficacious treatment of fresh perishable products by gas effluents plasma-enriched by reactive oxygen or nitrogen species. The easy implementation of the proposed indirect approach and the easily customizable CAP system at room temperature could gain great attention from fresh dairy sector, with economic advantages and benefits also for the environment.     

考虑电商平台信用支付促销的供应链协调研究

考虑到我国越来越多的电商平台为消费者提供基于互联网的信用支付策略作为重要的促销手段,构建了二级供应链中促销努力水平影响消费者需求的函数,研究其定价和促销努力水平协调问题。利用Stackelberg博弈分析供应链主体间的最优决策,并与集中模式下进行对比分析,为了促使电商平台提高促销努力水平,构建了“成本共担-收益共享”契约达到供应链协调的目的。通过数值分析证明：“成本共担-收益共享”契约对电商平台的促销努力水平具有显著的提升作用;促销努力水平弹性系数对于促销努力水平具有一定的影响,在一定区间内,增加促销努力水平弹性系数将使供应链各企业的利润增加,一旦促销努力弹性系数超过一个临界值就会使得供应链各主体的利益受损。     

热裂法切割玻璃等硬脆材料关键技术研究进展

热裂法自1967年提出至今已取得丰硕成果。为使国内外学者清晰掌握其研究体系和发展趋势, 有必要对热裂法近60年的研究成果进行规律性总结。本文首先明确提出热裂法的发展路线分两个方向: 非预制轨迹热裂切割和预制轨迹热裂切割。在非预制轨迹热裂切割研究领域, 切割速度、裂纹轨迹偏移量和切割面质量是最主要的优化目标参数; 在预制轨迹热裂切割研究领域, 切割速度和切割面质量是最受关注的优化目标参数。针对上述目标参数的优化, 均可通过采用新的热源形式、冷却形式和优化工艺流程得以实现, 指出热裂法切割玻璃和陶瓷关键技术研究方向在于创新发展新的热源技术、冷却技术和进一步优化工艺流程。     

冰雪运动主题网络游戏临时用户模型研究

目的从用户体验角度出发,总结出针对冰雪运动主题网络游戏的临时用户模型,理论上为后续冰雪运动主题网络游戏设计研究提供研究思路与方法,实践上通过建立临时用户模型快速了解用户需求,增强网络游戏产品的更新迭代、满足用户多感官体验的需求。方法根据Alan Cooper提出的临时用户模型理论,对冰雪运动主题游戏用户进行划分,通过挑选出用户研究相关因子等建立临时用户模型。结论建立3个冰雪运动主题网络游戏临时用户模型,并结合相关主题的冰雪运动游戏进行测试及访谈,验证临时冰雪运动主题网络游戏临时用户模型,提出相关应对建议。通过总结冰雪运动主题网络游戏设计中临时用户模型的研究方法提出相关对策,为后续的虚拟冰雪游戏设计提供思路。     

Na0.5Bi0.5TiO3−BaTiO3−SrTiO3陶瓷的相图及电致伸缩性能

目的 利用SrTiO3调控Na0.5Bi0.5TiO3−BaTiO3−SrTiO3(NBT−BT−ST)三元系陶瓷的相结构,在室温下获得性能优异的电致伸缩材料,该材料可用于包装机械物料供给微振动器的研发。方法 采用传统固相合成法制备(1−x)[0.94NBT−0.06BT]−xST陶瓷。在分析(1−x)[0.94NBT−0.06BT]−xST陶瓷相图的基础上,阐述不同相区应变的来源,并系统研究弛豫相区陶瓷铁电、应变和电致伸缩性能等。结果 随着ST含量的增加,(1−x)[0.94NBT−0.06BT]−xST陶瓷的相结构由三方相、四方相两相共存→四方铁电相→铁电相、弛豫相共存→弛豫相。三方、四方两相共存区陶瓷的应变主要来源于晶格变形和非180^o畴转向。铁电、弛豫两相共存区陶瓷的应变主要来源于电场引发弛豫相和铁电相的相变。弛豫相区陶瓷的应变主要来源于样品晶格本征变形产生的电致伸缩效应。在弛豫相区,随着ST含量的增大,(1−x)[0.94NBT−0.06BT]−xST陶瓷的弛豫性增强,电滞回线逐渐变瘦,应变和滞后性均出现不同程度的降低,其中,x=0.40的样品在电场强度60 kV/cm下的应变滞后性降至7.8%,表现出典型的电致伸缩特征。在较强的弛豫性和形成纳米极性微区的作用下,在组分x=0.40时陶瓷在电场强度50 kV/cm下的电致伸缩系数高达0.021 3 m⁴/C²。结论 通过ST调控NBT基陶瓷的相结构,在弛豫相区能够有效地改善其电致伸缩性能。利用该技术制备的陶瓷电致伸缩材料可为包装机械物料供给微驱动器的研发和改进提供技术支持。     

热丝CVD法制备金刚石涂层刀具的研究现状

金刚石涂层刀具具有优异的硬度、耐磨性及导热性,在军事、航空航天等高精尖应用领域加工石墨、高硅铝合金、碳纤维增强塑料等难切削材料时无可替代,但目前金刚石涂层刀具存在两个问题:一是涂层与刀具间膜基结合力较差,导致涂层在使用中过早脱落;二是涂层表面粗糙度较大,难以保证被加工面的平整度与尺寸精度。本文从增强涂层结合力与降低涂层粗糙度两方面,将近年来科研人员对HFCVD法制备金刚石涂层的研究成果加以综述,并分析了各种因素对金刚石涂层刀具性能的影响。