不同燃料的喷嘴内流动与喷雾形态可视化试验

采用高速可控闪光摄影技术搭建了喷油器喷孔内流动及近场喷雾可视化试验装置,针对柴油、汽油、乙醇柴油、生物柴油4种燃料,对实际尺寸的透明喷油器喷孔内的流动及近场喷雾进行了对比试验研究。试验研究结果表明:所有试验燃料喷孔内均呈现空穴流动,低运动粘度、高饱和蒸气压的燃料空穴生成时刻更早、空穴强度更强;喷孔空穴强度较大的燃料具有更大的近场喷雾锥角;喷射结束后喷孔内会产生气体倒流现象并形成初始气泡,初始气泡体积随燃料表面张力的减小而增大。同时发现,针阀运动会对压力室和喷孔内的流动产生极大的扰动并影响其流动形态。     

基于CiteSpace可视化分析有机肥料研究进展

从Wo S数据库核心合集中检索出1900—2019年相关文献4473篇,运用CiteSpace知识图谱分析工具,对合著国家、机构、作者、学科领域、关键词、文献共被引网络等进行可视化分析,对有机肥料的研究进展及演变趋势进行图谱解读与分析:①有机肥料对改善土壤理化性状、抑制土传病害、提高作物产量品质的作用及其机理依然是研究重点;②最新的基因测序等分子生物学技术在有机肥料研究中将得到更加广泛应用;③添加天然沸石、生物质炭等物质制造有机类肥料是未来有机肥料加工的重要方向;④有机肥料研究具有很强的学科交叉性,涉及农业、化学、环境生态学、环境科学、工程学等众多学科领域;⑤中国有机肥料研究发展迅速,国际上合作发表有机肥料学术论文数量前三的研究机构分别是中国科学院、南京农业大学、中国农科院,具有重要的学术影响力。     

Understanding the mechanism of change in morphological structures,visualization features,and physicochemical characteristics of adlay seeds (Coix lacryma-jobi L.): The role of heat soaking

Heat soaking is an essential factor deciding the final quality of hard-to-cook grains. In this study, the morphological structures, visualization features, and physicochemical characteristics of adlay seeds soaked at 30–70 °C were investigated compared with waxy rice (easy to cook). The morphology of macromolecules and section cracks were observed by scanning electron microscopy and light microscopy as these are the crucial factors for penetrate water penetration, which showed that starch granules were slightly eroded when adlay seeds were soaked at 70 °C. The MRI images showed that at higher soaking temperatures, the moisture of soaked adlay seeds was distributed more evenly across a gradient. Meanwhile, heat soaking has a minor effect on starch and protein content of adlay seeds, and the proportion of bound water of adlay seeds slightly declined after heat soaking. Moreover, hardness analysis and pasting measurements exhibited structural changes and viscosity transition in the grains. However, the contribution of heat soaking to the infrared spectrogram and relative crystallinity of adlay seeds was insignificant. This study provides effective methods to evaluate changes in adlay seeds during heat soaking and explains why it is hard to cook.     

农业面源污染研究可视化分析

了解国内近年来的农业面源污染领域研究现状,获取该领域目前研究的内容及热点重点,并借此预测中国农业面源污染研究领域未来的发展趋势。以2008—2019年CNKI（中国知网）中涉及农业面源污染的1000篇较有代表性的文献（其中包括核心期刊论文、硕士论文和博士论文）为基础,采用可视化分析方法,分析此领域研究现状及发展趋势,结果表明农业面源污染研究领域发文总量整体呈现上升趋势;高频词汇主要包括化肥、禽畜粪便和农户等。从时间线看,前期研究重点集中在污染的现状、目标地区的污染负荷、地表及地下径流的情况、化肥的使用量等方面,而后期,农业面源污染的防控防治、国家的控制政策、污染控制技术等作为高频词开始出现,表明国家对农业面源方面污染的防控越来越重视。本研究结果可以为中国农业面源污染的防治及政策制定提供一定的参考数据。     

基于社会网络分析的国内语义检索领域作者合作研究

显性作者合作和隐性作者合作是科学研究中作者合作关系中的两个重要研究方面。文章采用社会网络分析方法,研究国内语义检索领域的显性作者合作关系,然后基于关键词耦合方法来挖掘该领域的隐性作者合作关系,以期为作者间的知识交流及信息传递提供依据。     

Correlation analysis between visualization of hemorrheologic changes and platelet function in patients with acute coronary syndrome after percutaneous coronary intervention

AIM:To intuitionally observe the characteristics of blood rheology in the patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI) for 1 year to 3 years by micro-channel array flow analyzer (MC-FAN) combined with other platelet function indexes, and to explore the correlations between the test results of MC-FAN and platelet function. METHODS:This study brought 74 patients with ACS after PCI for 1 year to 3 years into test group, and 21 healthy subjects were enrolled as normal group. The levels of platelet aggregation test (PAgT), platelet adhesiveness test (PAdT), P-selectin, platelet-derived growth factor BB (PDGF-BB) and von Willebrand factor (vWF) were detected. MC-FAN HR300 was used to detect the transiting time (MC-FAN TT) of the blood passing through the model body capillaries. The differences of the test results between the 2 groups were compared, and the correlations between the results of MC-FAN and platelet function in the patients with ACS after PCI were also explored. RESULTS:Compared with normal group, the MC-FAN TT in test group was prolonged (P<0.01), the ability of erythrocyte deformation was weakened, and the leukocyte attaching the vascular wall and platelet adhesion and aggregation relatively increased. The levels of PAgT, PAdT, P-selectin and PDGF-BB in test group were all higher than those in normal group (P<0.01). No difference of vWF between the 2 groups was observed. The intergroup correlation analysis showed that there were correlations between MC-FAN TT and platelet function, in which 10 μL MC-FAN TT and 30 μL MC-FAN TT had the most significant correlation with P-selectin (r=0601, P<0.01; r=0334, P<0.01), 60 μL MC-FAN TT had the most significant correlation with PAgT (r=0527, P<0.01), and 100 μL MC-FAN TT had the most significant correlation with PAdT (r=0. 815, P<0.05). CONCLUSION:The visualization of hemorrheologic changes and platelet function in the patients with ACS after PCI are abnormal.There are correlations between MC-FAN TT and platelet function.The results of MC-FAN can objectively evaluate the blood rheology of the patients, and provide the reference for clinical treatment.     

植物叶脉可视化造型研究

提出了植物叶脉可视化建模方法,包括植物叶的形态几何建模及植物叶脉的形状建模.植物叶的形态几何模型采用矩形形状变形;同时对植物叶脉的形状建模提出了多种构建方法.利用非线性多项式生成羽状叶序,提出了基于种子生长的随机迭代方法生成网状脉及基于叶片生长方法生成掌状脉序.方法简单易行,可控性好,易于构造各种不同类型的叶脉.通过给出的树叶模拟结果,表明其仿真效果较好.     

林业科学与科学可视化

本文概述了科学可视化对推动科学技术的发展所产生的巨大影响，以及在各领域的科研生产中所发挥的重要作用，并着重分析了可视化技术在林业科研领域中应用的特点、现状和应遵循的发展途径。另外，本文还介绍了作者在森林景物的视景仿真方面的研究成果和经验，并指出了可视化技术在林业科研领域应用中存在的问题和亟待解决的几个关键技术，即（1）自然景物的计算机图形的生成问题；（2）图形数据库管理技术；（3）交互界面的辅助设计工具的开发；（4）多种数据源的一体化管理。最后，对可视化技术在林业科学领域中的应用前景做了美好的憧憬。     

近年来土壤重金属研究知识图谱分析及关键主题述评

土壤重金属污染问题一直都是环境科学的热点与前沿。为深刻了解国内外这一领域的关键主题及最新动态,本文以Web of Science和CNKI期刊数据库检索的文献数据为样本,以CiteSpace为分析平台,从国家、机构、作者、研究热点等诸多方面,对土壤重金属研究的现状及关键主题进行了可视化分析。结果表明,国际上土壤重金属研究呈现多样化趋势,并且中国占居核心地位;关键主题集中于污染物来源与分布、污染评价及污染修复三大领域;当前研究偏重于环境科学、农学、工程技术、化学、地质学、毒理学以及植物学的相关研究。预计未来土壤重金属研究将呈现国际化、多学科综合化、多技术协同化发展的趋势。     

压铸件凝固过程温度场变化的计算机模拟

针对复杂、薄壁压铸件，研究提出了对其实体模型进行计算机自动网格划分及对温度场变化进行计算机模拟的物理建模方法、计算方法及判定算法，并对计算结果进行了可视化。应用结果表明效果良好。