The production of Indo-Pacific monochrome drawn glass beads in the Sasanian Empire: Insights from Xinjiang,northwest China

Indo-Pacific glass beads are produced by the drawn technique, which originates from South Asia, and their chemical compositions are unique in South and Southeast Asia. However, a small number of Indo-Pacific beads with Sassanian glass compositions are excavated in Asia and Africa after the 3rd c. CE, and their production sites in South/Southeast Asia or in the Sassanian region remain controversial. In this study, 15 drawn glass beads with various colours from Astana necropolis (ca. the 4th-8th c. CE) in Xinjiang, northwest China were investigated by using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), Scanning Electron Microscope, Raman spectroscopy and visible to near-infrared spectroscopy to characterize the production technology and origins. The results show that most Astana glass beads share similar chemical compositions with the glassware from Veh Arda?īr, a famous Sasanian site. Furthermore, Sasanian glass compositions predominate in Indo-Pacific beads in Xinjiang during the 4th-8th c. CE, while popular glass recipes in contemporary South/Southeast Asia are infrequently found; thus, it is deduced that the drawn method should have been mastered by Sasanian craftsmen. Moreover, the cobalt materials in Sasanian glass were imported from further western regions and changed over time. The popular Sasanian glass across central Eurasia reflects the trade monopoly of Sasanian in West and Central Asia, and the land glass bead trade is distinct from the contemporary maritime trade in the Indian and Pacific Oceans.     

Combination of heat treatment and chitosan coating to improve postharvest quality of wolfberry (Lycium barbarum)

The synergistic application of hot water dip at 42 °C for 30 min and 1% chitosan coating on differentiation in postharvest quality traits, microstructure as well as microbiological evolution of wolfberry fruits was investigated. Fresh wolfberry fruits were stored at 2 ± 0.5 °C and 90% relative humidity (RH) for 28 days. Results indicated the combination of prestorage heat treatment and chitosan coating maintained higher levels of ascorbic acid, total phenolic contents and antioxidant capacity as well as lower decay, compared with untreated wolfberry fruits. The possible mechanism was that the heat treatment almost sealed open stomata to limit the sites of pathogen penetration into fruits independently, followed by the biofilm formed by chitosan which controlled secondary infections as well as slowed changes in fruit respiration and metabolic activity in wolfberries. The synergistically treated fruit also exhibited a higher acceptability obtained by sensory analysis after cold storage. In this sense, the integrated application of heat treatment and chitosan coating could be regarded as an effective strategy to extend storage life and maintain the postharvest quality of wolfberry fruits.     

结合位图切割和区域合并的彩色图像分割

就经典分水岭图像分割算法中存在的过分割问题，提出一种结合位图切割和区域合并的彩色图像分割算法。对原始彩色图像通过空域梯度算子求其梯度图像，并利用位图切割重建梯度图像；对新梯度图像进行分水岭预分割；对预分割图像基于异质性最小原则进行区域合并，并获得最终分割结果。相比于现有的同类方法，该算法引入位图切割，抑制噪声对分割结果的影响，在边缘模糊处分割准确，得到符合人类视觉的较小分割区域数目，同时在运行效率上提高。     

基于时空的弱点状运动目标检测技术

如何在复杂背景下持续有效地检测目标位置,一直是研究者们需要面对的主要挑战。本文在研究红外点状移动目标特征的基础上,根据目标无纹理,无形状的特性,提出一种改进的形态学目标增强算法,并利用目标连续时空不变性检测目标。首先,建立多尺度的图像金字塔,在每层上采用改进的形态学算法快速、粗糙定位小目标。然后进一步的根据目标在时空上的位置相关性,提出基于目标运动特征分析的精确检测方法。得到精确稳定的检测结果。最后实验结果表明与经典的形态学检测算法及其他算法相比,该技术能更有效地检测弱小目标,具有更高的鲁棒性。     

管式段塞流捕集器构造及其优化设计

天然气近年来由于技术的进步及其自身多项优势而被广泛利用,油气混输作为一种经济性良好的运输方式也开始服务于各大油气田。然而多相流的运动很复杂,加上一些其他因素而产生的段塞流则是危害较大,其主要危害体现在各项参数不稳,混输管路下游的处理设备会受到较大冲击,因此需要在混输管路末端设置段塞流捕集器来缓解这种冲击,保证下游的稳定供给。     

P(DBF-VA)型柴油低温流动性改进剂的研制

针对新疆地产柴油蜡含量较高的特点,以游离基聚合法合成了富马酸双链混合酯和醋酸乙烯酯共聚物型[P(DBF-VA)]柴油低温流动改进剂,利用正交实验研究了单体配比,引发剂用量,溶剂用量,聚合温度对聚合物降冷滤效果的影响。共聚物用IR进行表征,利用XRD初步探讨了该降凝剂的降凝机理。结果表明:该剂能使吐哈—10~#、0~#柴油冷滤点降低10℃和7℃;使独山子0~#柴油冷滤点下降12℃;使石化0~#柴油冷滤点下降8℃;使克拉玛依0~#柴油的冷滤点下降8℃。     

天然气产业链下游市场风险评价模型探讨

随着我国天然气主干管网的逐步形成，天然气产业链下游市场正在进入快速成长阶段，建立风险预警系统的重要性开始显现，而风险评价模型是其基础工作之一。文章在天然气产业链下游区域市场风险评价指标体系的基础上，综合运用层次分析法和灰色系统理论，建立了对天然气产业链下游区域市场风险评价的模型，并以各区域市场的用气量占全国总用气量的比重为权重，建立起完整的市场风险评价模型，可为评价天然气产业链下游市场整体市场风险时参考。