Multi-Layer Simulation of the Powder Bed Selective Laser Processing of Alumina for Residual Stress and Distortion Evaluation

A numerical model was developed to simulate the real process of alumina powder bed selective laser processing (PBSLP) to thoroughly investigate the residual stress and distortion experienced in printed parts when multi-layer scanning with a CO₂ laser source is considered. The model contains a user-defined function (UDF) for the laser source, temperature-dependent material properties, scanning strategies, and build orientations, and it is solved using ANSYS 2020R2. In addition, the model’s validation was confirmed with experimental results. The results revealed that a high scanning speed (up to 1200 mm/s) and low laser power are effective for the PBSLP of alumina, owing to alumina’s high absorptivity for CO₂ lasers, and a high manufacturing rate can be achieved. During the multi-layer printing simulation, the accumulated heat inside the part increased gradually with an increased number of printed layers. Additionally, the calculated residual stress exceeded the yield limit for all the studied build orientations due to the printed part’s high-temperature difference. When preheating was applied, the residual stress decreased by 23% and the distortion decreased by 54%. For the successful PBSLP of ceramics, commercial printers cannot be used effectively. A particular printer equipped with a temperature controller and a preheating system is required for ceramics.     

Zapline‐plus: A Zapline extension for automatic and adaptive removal of frequency‐specific noise artifacts in M/EEG

Removing power line noise and other frequency‐specific artifacts from electrophysiological data without affecting neural signals remains a challenging task. Recently, an approach was introduced that combines spectral and spatial filtering to effectively remove line noise: Zapline. This algorithm, however, requires manual selection of the noise frequency and the number of spatial components to remove during spatial filtering. Moreover, it assumes that noise frequency and spatial topography are stable over time, which is often not warranted. To overcome these issues, we introduce Zapline‐plus, which allows adaptive and automatic removal of frequency‐specific noise artifacts from M/electroencephalography (EEG) and LFP data. To achieve this, our extension first segments the data into periods (chunks) in which the noise is spatially stable. Then, for each chunk, it searches for peaks in the power spectrum, and finally applies Zapline. The exact noise frequency around the found target frequency is also determined separately for every chunk to allow fluctuations of the peak noise frequency over time. The number of to‐be‐removed components by Zapline is automatically determined using an outlier detection algorithm. Finally, the frequency spectrum after cleaning is analyzed for suboptimal cleaning, and parameters are adapted accordingly if necessary before re‐running the process. The software creates a detailed plot for monitoring the cleaning. We highlight the efficacy of the different features of our algorithm by applying it to four openly available data sets, two EEG sets containing both stationary and mobile task conditions, and two magnetoencephalography sets containing strong line noise.     

Study on Hot Deformation Behavior of an Antibacterial 50Cr15MoVCu Tool Steel

Hot deformation behaviors of an antibacterial 50Cr15MoVCu tool steel were studied. The flow stress curves presented three typical characteristics: (i) a single peak dynamic recrystallization curve, (ii) a monotone incremental work-hardening curve, and (iii) the equilibrium dynamic recovery curve. The flow stress increased with the increase of the deformation rate at each deformation temperature and decreased with the increase of the deformation temperature at the same deformation rate. The thermal activation energy and material constants were Q of 461.6574 kJ/mol, A of 3.42 × 10¹⁷, and α of 0.00681 MPa⁻¹, respectively. The high temperature constitutive equation was: Z=ε˙expQ/RT=3.42×1017sinh0.0068×σ5.6807. Based on the processing maps and microstructure evolution, the best hot working process was a deformation temperature of 1050 °C and deformation rate of 0.001 s⁻¹.     

麻黄汤中臣佐使药对君药中伪麻黄碱的人体药代学的影响

目的:以君药效应成分伪麻黄碱(pseudo-ephedrine,PE)为指标,用GC-MS法考察不同配伍对PE药代学参数的影响规律,探索麻黄汤方中臣佐使药对君药人体内过程的影响。方法:对麻黄汤作正交设计拆成8个配伍组,每组8名健康男性志愿者,服药后在不同时间点抽取静脉血,测定血清中PE的含量,绘制药-时曲线;选用药代软件Win-Nonlin4.0.1求算药代学参数;采用SPSS10.0软件对药代参数进行统计分析。结果:所有药时曲线均符合无滞后开放式一房室动力学模型;不同配伍对PE的部分药代学参数有显著影响(P<0.05);方中各药味对PE的部分药代参数的影响有显著交互作用(P<0.05)。结论:臣佐使药对方中君药有效成分伪麻黄碱的药代学参数有一定影响。     

中药复方防治急性肺损伤的作用机制研究进展

急性肺损伤(acute lung injury,ALI)是各种直接或间接因素导致的肺泡上皮细胞及毛细血管内皮细胞损伤,能造成弥漫性肺间质及肺泡水肿,由其导致的急性低氧性呼吸功能不全,是临床上常见的危重病症,至今尚缺乏有效的治疗药物.中药复方在防治肺损伤方面日益显示其优势,其作用机制研究也不断深入.作者分别从抑制炎性反应、调节免疫功能、抗氧化、调节凝血和纤溶系统的异常、上调水通道蛋白及减轻肺纤维化等6方面,对近3年来相关研究进展进行综述,并总结了中医治则与现代药理机制之间的关联,以期为研制防治ALI的创新药物提供一定依据和线索.     

星点设计-效应面法优化炒茺蔚子炮制工艺

目的:利用星点设计-效应面法对炒茺蔚子的炮制工艺进行优化,为炒茺蔚子的规范化生产提供依据。方法:采用清炒法,以炮制温度、炮制时间、炒药机转速为自变量,总生物碱、盐酸水苏碱、水溶性浸出物、醇溶性浸出物质量分数为评价指标,对自变量各水平进行多元回归拟合,利用效应面法筛选最佳炮制工艺并进行预测分析。采用UV测定总生物碱的含量,检测波长520 nm;采用高效液相色谱仪-蒸发光散射法测定盐酸水苏碱的含量,流动相乙腈-水(60∶40),流速0.5 m L·min~(-1),漂移管温度70℃。结果:三项式拟合复合相关系数较高。最佳炮制工艺为炮制温度219℃,炮制时间2 min,炒药机转速14 r·min~(-1)。总生物碱、盐酸水苏碱、水溶性浸出物、醇溶性浸出物质量分数的平均值分别为9.82,2.50,86.16,193.28 mg·g~(-1),综合评分与三项式拟合方程预测值偏差0.87%。结论:利用星点设计-效应面法优化炒茺蔚子炮制工艺的方法简便且预测性良好,适用于炒茺蔚子的规范化生产。     

何首乌及炮制品中二苯乙烯苷的稳定性研究

[目的] 研究何首乌生品及不同炮制品中2,3,5,4’-四羟基二苯乙烯-2-O-β-D-葡萄糖苷（TSG）的稳定性。[方法] 采用高效液相色谱（HPLC）及高效液相色谱-质谱联用仪（LC-MS）,系统考查了光照、温度和铁离子（Fe³⁺）浓度等因素对TSG单体、何首乌生品及炮制品中TSG的影响。[结果] 各个因素对TSG的稳定性均有不同程度的影响。其中光照、温度等因素对TSG单体、何首乌生品及其炮制品中TSG的影响并不存在明显差别,而Fe³⁺对何首乌生品及其炮制品中反应平衡点存在明显差别,推测可能原因是何首乌中的其他相似结构的二苯乙烯类成分与TSG竞争消耗Fe³⁺所致。[结论] 文章对何首乌指标成分的稳定性影响因素进行了系统研究,为规范其加工、贮藏、炮制和制剂相关研究奠定一定基础,为相似成分的稳定性研究提供了参考。     

建昌帮蜜糠炒白术炮制工艺优化

目的优选建昌帮蜜糠炒白术的炮制工艺。方法以白术内酯I、白术内酯II、白术内酯III、苍术酮、醇浸出物质量分数为指标,HPLC法及《中国药典》2010年版中的醇浸出物法测定各个指标,采用L9(34)正交试验,确定其最佳炮制工艺参数:蜜糠用量、炒制温度和炒制时间。结果蜜糠炒白术的最佳工艺:辅料蜜糠用量为50%(占药材质量的百分比),炒制温度为200℃,炒制时间为5 min。结论最佳炮制工艺经验证,稳定可行。     

盐黄柏炮制历史沿革和机制的研究进展及其质量标志物（QMarker）预测分析

盐黄柏是黄柏Phellodendri Chinensis Cortex经盐水加工后的炮制品,具有滋阴降火的功效,在我国具有广泛且悠久的应用历史。通过查阅历代本草典籍及现代研究文献报道,梳理盐黄柏的历史沿革,并对其现代炮制机制的研究进展进行归纳。从药性、盐制后化学成分与功效变化、药动学及体内过程相关性等方面对盐黄柏的质量标志物(quality marker,Q-Marker)进行预测分析,初步确定小檗碱、小檗红碱、黄柏碱等为其可能的Q-Marker,以期为盐黄柏的质量评价、临床有效应用及相关基础研究提供科学依据。     

不同炮制方法对吴茱萸中3种指标性成分含量的影响研究

目的:比较吴茱萸生品及不同炮制品中吴茱萸内酯、吴茱萸碱及吴茱萸次碱的含量差异。方法:采用Agilent C18色谱柱(4.6 mm×250 mm,5μm),以乙腈-水(45∶55)溶剂系统为流动相,检测波长为225 nm。结果:吴茱萸生品及不同炮制品中三种成分的含量存在明显差异。结论:不同炮制品中吴茱萸内酯、吴茱萸碱及吴茱萸次碱的含量不同,为临床用药提供科学的依据。