无人机遥感影像快速拼接方法研究

无人机低空遥感技术作为一种新兴的低空遥感技术,具有灵活性强、操作方便、现势性好、分辨率高、投入低等众多优点,已成为遥感数据获取不可或缺的手段之一。本文针对无人机影像量大、无规律、像幅小、拼接困难的特点,通过试验研究对比了几种无人机低空遥感影像拼接方法,并分析其拼接影像的精度及应用范围。     

我国光稳定剂市场现状

文章介绍了光稳定剂的种类，阐述了我国光稳定剂的市场现状，并对其未来市场进行了预测。     

UVA紫外辐射对室内碳纤维增强环氧树脂基复合材料性能的影响

研究了Ultraviolet A(UVA)紫外辐射对碳纤维增强环氧树脂基复合材料产生的影响。测量和分析了从窗户照射到室内太阳光和日光灯辐射的UVA紫外线辐照度, 研究了碳纤维增强环氧树脂基复合材料经辐照度为200 μW·cm^-2的UVA紫外灯辐射处理后的力学性能变化, 并通过XPS、 接触角、 纳米压痕、 原子力显微镜(AFM)测试方法研究了其表面性能变化。结果表明: 春夏季节晴天室内太阳光紫外辐照度在14点时达到最大值, 距离窗户0 m处最大值为375 μW·cm^-2, 1 m处最大值迅速降至30 μW·cm^-2; 对功率40 W的日光灯, 距离日光灯0 m处, 紫外辐照度为87.3 μW·cm^-2, 1 m处快速降至5.4 μW·cm^-2; 经过45天的紫外辐射, 碳纤维增强环氧树脂基复合材料的层间剪切强度、 弯曲强度和拉伸强度无明显变化; 碳纤维增强环氧树脂基复合材料表面发生氧化反应, 表面硬度和粗糙度变大。     

超声辅助CMT电弧增材制造TC4钛合金微观组织和力学性能研究

目的研究超声辅助对CMT电弧增材制造钛合金TC4微观组织及力学性能的影响。方法 CMT增材制造TC4钛合金的同时利用超声辅助设备进行振动辅助,采用不同的振动功率和不同的振动位置对增材后的TC4力学性能和微观组织进行对比分析。结果 600 W超声辅助振动基板时的钛合金试样成形美观,力学性能优异。水平方向上,抗拉强度平均值为952.7 MPa,伸长率平均值为7.46%;垂直方向上,抗拉强度平均值为905.83 MPa,伸长率平均值为11.03%,相较未施加超声振动增材试样的力学性能有明显提高。结论超声辅助的引入有效提高了熔池的深宽比,加快了熔池冷却速度,柱状晶尺寸也明显减小,针状马氏体数量增多,得到的钛合金力学性能和微观组织均良好。     

基于三支决策的双激素人工胰脏模型预测控制算法研究

目前,关于双激素人工胰脏子系统切换机制的研究较少,并且现有研究在运行效率和群体控制质量上有待提高.以三支决策理论和模型预测控制算法为依托,提出一种基于三支决策的双激素人工胰脏模型预测控制算法.该算法利用三支决策理论设计3个子系统之间的切换规则,该规则通过设计包含经济代价和高低血糖风险的代价矩阵,计算切换到每个子系统的决...     

Comparison of sun protection factors determined by an in vivo and different in vitro methodologies: a study with 58 different commercially available sunscreen products

An extensive study on the sun protection factors (SPF) of sun care products was carried out using the COLIPA (The European Cosmetic Toiletry and Perfumery Association) method, which relates to in vivo experiments. Furthermore, in vitro methods were tested with sunscreen formulations that were prepared as films on surface-roughened plates of polymethyl methacrylate (PMMA). One of the in vitro methods, i.e. using the sunscreen tester, has been recently developed, whereas the second has been defined by a pure spectroscopic approach, which is based on spectral transmission measurements of sunscreen films. Altogether 58 different sunscreen formulations, with manufacturer declared SPF values ranging from 4 to 60 and currently available on the European market, were investigated. The quality of correlations with results from the individual products based on the different in vitro methods versus the COLIPA values that were considered as generally accepted standard values was assessed. In this context, also variations because of sample preparation and spectral measurement were discussed. For sunscreen products with in vivo SPF values larger 25, the spectral transmittance within the UVA/UVB range is rapidly decreasing, which is experienced even for products with reduced amounts reaching 0.5 mg cm(-2) and still leading to unsatisfactory correlation of the spectroscopically derived SPF values versus the results from the alternative assays. Opposite to these small amounts, a sunscreen product spread of 2 mg cm(-2) is standard for the in vivo COLIPA method, whereas an area-normalized amount of 1 mg cm(-2) is currently routinely used for the sunscreen tester method. Furthermore, an overview of the individual product characteristics, such as their specific critical wavelengths and their UVA/UVB ratios is provided; both parameters can also be calculated from the spectral absorbances of the standardized sunscreen films.     

Effect of the mechanical activation on the photoelectrochemical properties of anatase powders

Mechanically activated anatase powders were used to assemble thin film electrodes for electrophotocatalytic applications. Flat band potential of the different samples, estimated from the dependence of photopotential on the light intensity, as well as photocurrent vs potential curves were measured at samples milled for different times and compared with those of the untreated anatase. The maximum performance is achieved at samples milled for very short times, at which the mechanical process gives rise to a mixed-phase titania catalyst constituted by anatase and TiO₂(II) phases. Electrochemical Impedance Spectroscopy measurements were also performed in order to individuate the controlling step of the photoelectrochemical process of water splitting.     

Minocycline Impact on Redox Homeostasis of Normal Human Melanocytes HEMn-LP Exposed to UVA Radiation and Hydrogen Peroxide

Minocycline is a semisynthetic tetracycline antibiotic. In addition to its antibacterial activity, minocycline shows many non-antibiotic, beneficial effects, including antioxidative action. The property is responsible, e.g., for anti-inflammatory, neuroprotective, and cardioprotective effects of the drug. However, long-term pharmacotherapy with minocycline may lead to hyperpigmentation of the skin. The reasons for the pigmentation disorders include the deposition of the drug and its metabolites in melanin-containing cells and the stimulation of melanogenesis. The adverse drug reaction raises a question about the influence of the drug on melanocyte homeostasis. The study aimed to assess the effect of minocycline on redox balance in human normal melanocytes HEMn-LP exposed to hydrogen peroxide and UVA radiation. The obtained results indicate that minocycline induced oxidative stress in epidermal human melanocytes. The drug inhibited cell proliferation, decreased the level of reduced thiols, and stimulated the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). The described changes were accompanied by an increase in the intracellular level of ROS. On the other hand, pretreatment with minocycline at the same concentrations increased cell viability and significantly attenuated the oxidative stress in melanocytes exposed to hydrogen peroxide and UVA radiation. Moreover, the molecular docking analysis revealed that the different influence of minocycline and other tetracyclines on CAT activity can be related to the location of the binding site.     

查耳酮衍生物接枝改性的聚硅氧烷UVA滤光剂

制备了查耳酮衍生物（E）-3-（4-烯丙氧基）苯基-1-苯基丙-2-烯-1-酮（Blank-Cha），（E）-3-（4-烯丙氧基）苯基-1-（4-羟基苯基）丙-2-烯-1-酮（Oxhydryl-Cha）和（E）-3-（4-烯丙氧基）苯基-1-（4-甲氧基苯基）丙-2-烯-1-酮（Methoxy-Cha）。再通过硅氢加成反应将Methoxy-Cha接枝到含氢硅油链上，制备了聚硅氧烷UVA滤光剂（WPUF）。采用NMR、LC-MS及FTIR鉴定产物化学结构，证明查耳酮衍生物和WPUF成功合成。研究了不同取代基对查尔酮衍生物的光吸收性能和细胞毒性的影响。结果表明，查耳酮衍生物摩尔吸光系数ε＞10000，Methoxy-Cha的细胞毒性最低；避光6个月和90 ℃加热12 h后WPUF的化学结构无变化，模拟阳光照射4 h后紫外吸收能力仅损失30.46%，且WPUF在250 μg/mL及以下的浓度不表现出细胞毒性。体外透皮试验结果表明WPUF角质层平均渗透深度为11 μm。体外测定WPUF的SPF值为36.21，与商用防晒剂相当。