Nanocrystalline Cellulose– and Graphene Oxide–reinforced Polyvinyl Alcohol Films: Synthesis,Characterization, and Origin of Beneficial Co-filling Effects

Applied Composite Materials - The increased demand for durable yet flexible and stretchable membranes has inspired the investigation of polymer nanocomposite films, such as those based on polyvinyl...     

柑桔精油中d-苧烯的转化研究

本课题以冷榨、高速离心分离、己烷低温浓缩的方法从柑桔皮渣中成功地提取了柑桔精油 ,产率达 8.81克 /千克柑桔皮。并探讨了以粉碎———绝氧陈化———紫外线激活的方法 ,让柑桔皮中的自体酵素发酵催化 ,将柑桔精油中的d-烯转化成含氧萜烯类 ,降低了精油中碳氢萜类 ,相对提高了含氧萜烯类含量 ,从而明显地提高了柑桔精油的产量和香气品质。     

Ultrasonic improvement of rheological behavior of polystyrene

The effects of ultrasonic oscillation on die pressure, productivity of extrusion, melt viscosity, and melt oscillating flow of polystyrene (PS) as well as their mechanism were studied in a special ultrasonic oscillations extrusion system developed in our lab. The experimental results show that in the presence of ultrasonic oscillations, the PS melt oscillating flow or surface distortion of PS extrudate is inhibited or disappears. The surface appearance of PS extrudate gets greatly improved. The die pressure, melt viscosity, flow activation energy, and consistency efficiency of PS decreased and the productivity of PS extrudate increased in the presence of ultrasonic oscillation. The shear sensitivity of PS melt viscosity is decreased because of the increase of its power law index in the presence of ultrasonic oscillation. Introduction of ultrasonic oscillation into PS melt can greatly improve the processibility of PS. Their possible mechanism is also proposed in this article. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2451–2460, 2002     

Effect of ultrasonic oscillations on weld line strength of PS,PMMA, and their blends

The effect of ultrasonic oscillations on the weld line strength of amorphous polystyrene (PS), polymethyl methacrylate (PMMA), and PS/PMMA (20/80, 50/50, 80/20) blends at various temperatures was investigated. By facilitating the molecular diffusion across the weld line, the introduction of ultrasonic oscillations could evidently improve the weld line strength of PS, PMMA, and their blends. The different effects on the weld line strength of PS/PMMA (20/80, 50/50, 80/20) blends were investigated. The ultrasonic oscillations could greatly increase the weld line strength of PS/PMMA (80/20) by ～ 70%, but was less efficient to PS/PMMA (50/50, 20/80) blends, due to the great difference of weld line morphologies of these blends. The dispersed phase of PS/PMMA (80/20) in the weld line was spherical while two different morphologies in the weld line of PS/PMMA (50/50) were observed. And the stripe‐like morphology of PS perpendicular to the flow direction in the weld line of PS/PMMA (20/80) is responsible for the little effect of ultrasonic oscillations. The fractured surfaces of PS, PMMA, and PS/PMMA (80/20) with weld line became much rougher due to the introduction of ultrasonic oscillations. The morphology study of PS/PMMA (80/20) showed that the spherical dispersed phase of PS/PMMA at the skin turned smaller under ultrasonic oscillations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2990–2997, 2006     

Mechanically Strong and Ductile Polypropylene/Poly(ethylene-co-octene) Blends Prepared Through Multistretched Extrusion: Morphological Evolution,Toughening, and Reinforcing Mechanism

In this paper, polypropylene matrix with densely stacked shish-kebab crystalline structure and dispersed poly(ethylene-co-octene) phase with micro/nanofibers were formed simultaneously in polypropylene/poly(ethylene-co-octene) blends through multistretched extrusion. The as-obtained highly oriented and densely stacked shish-kebab crystalline structure can provide blends with greatly enhanced tensile yield strength. The as-formed poly(ethylene-co-octene) micro/nanofibers can toughen polypropylene matrix effectively through deflecting the crack, which is different from the toughening mechanism in polypropylene/poly(ethylene-co-octene) blends filled with spherical poly(ethylene-co-octene) particles. Compared with that of conventional polypropylene/poly(ethylene-co-octene) blends, the tensile yield strength of multistretched blends increased approximately 300%, while the notched impact strength declined slightly.     

“山竹”台风对广州市滨江园林树木的 影响——以临江大道及带状公园为例

临江大道及其带状公园是广州市沿江道路绿化和滨江绿地，是该城市园林景观的重要组成部分。由于2018年第22号“山竹”台风的影响，临江大道园林树木受损严重。基于临江大道行道树安全检测评估，综合“山竹”台风灾后临江大道及带状公园的树木受损情况进行了分析，结果发现不同的树种其抗风性差异较大；对6种重要的不同树种倒伏进行Logistic回归分析，发现相关的种树之间的倒伏差异极显著。从树木安全评估角度去探讨滨江园林树木受损、树种选择与种植情况，为华南地区城市滨江园林树木养护和修复提供参考和借鉴。     

广州南沙地区整体城市设计和重要节点城市设计

南沙地区整体城市设计和重要节点城市设计既尊重《南沙地区发展规划》“自上而下”的要求，又在分析南沙地区资源潜力的前提下，“自下而上”对相关规划提出了基于空间形态的调整意见，尤其是“创建南沙中心城”和“塑造宜人尺度滨海城市”的构思对南沙的未来发展有重要意义。     

钢管混凝土柱-环梁节点抗震性能的试验研究

混凝土环梁节点是钢管混凝土柱与混凝土梁连接的一种新型节点。通过14个钢管混凝土柱-环梁节点模型的低周反复荷载试验,研究了环梁节点的抗震性能。试验结果表明:无论塑性铰出现在框架梁端还是在环梁上,试件都有很好的弹塑性变形能力;达到最大承载力时,大部分试件的钢管柱转角即层间位移角已超过1/120,滞回曲线比较饱满;承载力下降时,滞回曲线虽有不同程度的捏拢,但不严重,试件有较好的耗能能力;环梁节点的钢管混凝土柱与环梁相对独立,节点的破坏基本上不影响钢管混凝土柱的承载力。     

某体育馆多次预应力钢网壳屋盖结构设计与研究

西昌铁路分局体育活动中心屋盖采用了“四加三卸”加载顺序的多次预应力钢穹网壳新型空间结构。设计时确定了预加应力体系结构的方案，配置了合理的预加力值，制定了可行的张拉工艺。实践证明该结构是一种高效、经济、安全、新颖的大跨空间承重结构体系，值得进一步研究推广。     

中国南方海相复杂山地页岩气储层甜点综合评价技术——以昭通国家级页岩气示范区为例

针对中国南方海相页岩气勘探开发所面临的"强改造、过成熟、复杂山地人文"等地质与地理条件,以云南昭通国家级页岩气示范区6年来的页岩气勘探甜点评价及黄金坝产区5×10~8m~3页岩气产能建设实践为支撑,在调研总结国内外页岩气储层评价认识的基础上,明确提出南方海相山地页岩气储层甜点评价中应补充页岩气保存条件、孔隙压力条件这2项关键指标,并应强化地应力与天然微裂缝系统评价研究。以此为基础,融合页岩气多学科资料进行系统分析并开展地质工程一体化综合研究,由此建立了页岩气储层"地球物理、储层地质、裂缝系统、岩石地质力学"三维模型。应用实践结果表明:①地质工程一体化和储层三维建模是中国南方海相复杂山地页岩气储层甜点评价的有效方法;②页岩气储层甜点评价体现了多属性、多项评价参数的三维空间叠合与叠加效应;③木桶短板原理决定了页岩气储层甜点区的分布格局和评选结果。结论认为:该页岩气储层甜点综合评价方法具有创新性,可有效规避复杂的地质风险和工程风险,对高效勘探开发南方海相页岩气具有指导意义。