Fast generation method of 3D scene in Chinese landscape painting

The three-dimensional (3D) modeling of Chinese landscape painting is of great significance for the digital protection of cultural heritage and the production of virtual reality content. A fast modeling method to create 3D landscape scenes for traditional Chinese painting is proposed in this paper, based on integrated terrain modeling and the water flow rendering algorithm. A height map generation algorithm based on auxiliary lines is first proposed to carry out fast modeling from a simple two-dimensional contour to create a 3D mountain model. A realistic flow simulation that fits the topography is then undertaken, based on a flow chart which is calculated using the particle force in the normal grid of topography, and the theory of smoothing particle hydrodynamics. Finally, a stylistic scene that conforms to the artistic concept of traditional Chinese painting is acquired by optimizing the parameters. The interactive modeling platform of the integrated algorithm is tested in this study, and compared with existing research. Results show the method can achieve real-time rendering and realistic rendering to rapidly generate a 3D scene model consistent with a traditional painting scene, and provide support for the follow up development of virtual reality applications.

     

黄河中下游沿黄城市水资源承载力贴近度空间结构及作用机理

采用贴近度测度黄河中下游31个沿黄城市水资源承载力,分析承载力贴近度的空间特征和空间作用机理。结果表明：黄河中下游流域城市水资源承载力整体偏低,尤其是下游流域沿黄城市的水资源供需矛盾尖锐;从空间结构特征全局看,31个沿黄城市水资源承载力整体呈现空间自相关特征,从局部看,大部分城市无分异特征,但中游流域出现热点区域,下游流域尤其是河南省出现低洼区域;通过沿黄城市水资源承载力贴近度空间作用机理分析,中游流域沿黄城市水资源承载力受到驱动力（D）、压力（P）、状态（S）、影响（I）、管理（M）5个因素的影响,且城市之间存在空间虹吸效应,水资源表现出空间竞争,而不是空间协同发展。下游流域沿黄城市水资源承载力只受到驱动力（D）、状态（S）、影响（I）3个因素的作用。研究成果可为沿黄城市加强水资源的管理、优化城市发展模式提供参考。     

六氟丙烯等离子体处理对聚丙烯驻极体性能的影响

以六氟丙烯(C3F6)为反应气体,通过等离子体激发使聚丙烯(PP)微粉表面氟化,并以此为原料采用热极化驻极制备了氟化改性PP驻极体.使用红外光谱、能谱分析、扫描电镜、差示扫描量热分析、X射线衍射、接触角测试仪及振动式电容静电计对氟化改性PP驻极体进行了表征,研究了氟化改性对其驻极性能的影响.研究结果表明,低温六氟丙烯等离子体处理PP微粉接枝了六氟丙烯;等离子处理后的PP微粉疏水性提高,水接触角最大为126°;在功率400 W下,随着等离子体处理时间的延长,氟化改性PP微粉表面氟含量先增大后减小;处理15 min时,表面氟含量达到最大值0.88％;驻极电压一定时,氟含量越高驻极体的初始表面电位越大,且储存电荷能力提高;等离子体氟化改性对PP结晶行为没有明显影响;热极化驻极由于存在外电场作用力,驻极体的熔融峰值增大约8℃;氟化改性PP驻极体对大肠杆菌有良好的抑菌活性.     

Preparation of poly(vinyl alcohol)-based separator with pore-forming additive for lithium-ion batteries

In this work, poly(vinyl alcohol) (PVA)-based separators with microporous structure were prepared from a casting solution composed of PVA resin, water as solvent, and poly(vinyl pyrrolidone) (PVP) polymer as pore controlling additive by non-solvent induced phase separation (NIPS) wet-process and investigated in lithium-ion batteries. The effects of PVP on the morphology and properties of the separator, such as porosity, electrolyte wettability, thermal stability and battery performance (discharge capacity, C-rate capability and cycleability) were systematically analyzed. Results show that PVP induced more pores on the bottom surfaces and the electrolyte uptake, ionic conductivity was further improved. Finally, a 10 wt% PVA-based separator with PVP solid content of 6 wt% exhibited greatly improved porosity, electrolyte uptake, ion conductivity and thermal resistance, resulting in the cell with high safety performance and matched electrochemical performance. The results demonstrated that the PVA-based separator with PVP as pore controlling additive can be a successful candidate serving as an effective separator for lithium-ion battery. Additionally, the present method of producing the microporous separator for LIBs is simple, environmentally benign and economically viable.     

配筋超高性能混凝土用作免拆模板对短柱力学性能影响的实验研究

为进一步提高在海洋浪溅区等严重氯盐腐蚀环境下混凝土结构的耐久性,采用以配筋超高性能混凝土(UHPC)用作免拆模板加素填芯混凝土的技术思路,通过轴压实验研究了配筋UHPC用作免拆模板对短柱轴压力学性能的影响。结果表明,与破坏时海工混凝土柱出现大量的混凝土剥落和钢筋裸露不同,UHPC免拆模板柱的整体性良好,表面的UHPC仅出现少量剥落且钢筋不外露。同时,在等截面和相同配筋的情况下,UHPC免拆模板方柱和圆柱的开裂荷载明显高于高强海工混凝土方柱和圆柱的极限荷载,且分别达到其自身极限荷载的93%和88%。考虑到混凝土对钢筋的有效保护是影响海工混凝土结构耐久性的重要因素,配筋UHPC用作免拆模板这一思路在提高柱体的极限承载力、延性、刚度的同时还可以提高结构的开裂荷载、抗裂性能,有效地提高结构耐久性,适用于沿海工程。其中圆柱的力学性能提高幅度要远高于方柱,从配筋UHPC免拆模板的使用效果和施工便利性考虑,优选UHPC免拆模板圆柱。     

Characteristics of flow fields in the gas–liquid mini-bubble columns with particle image velocimetry measurements

As a new type of gas–liquid microreactors, the gas–liquid mini-bubble column has potential applications. However, few studies on the flow fields in the mini-bubble column can be found at present. In this work, particle image velocimetry (PIV) was used to visually study the velocity fields, vorticity fields and bubble dynamics in the gas–liquid mini-bubble columns with column inner diameters of 1–3 mm and mini-bubble diameters ranged from 0.7 to 1.3 mm. It is found that with the increase of superficial liquid velocity, bubbles rose from almost straight line to Z-shaped or S-shaped trajectory, and the bubble trajectory changed from one-dimension to three-dimension; when the bubble velocity changed, the bubble size and gas holdup decreased; bubble terminal velocity was controlled by bubble buoyancy and flow resistance, and increased slightly with bubble coalescence. These findings may provide basic reference for the design and scale-up of such a mini-bubble column reactor.     

Principles of Amino-Acid-Nucleotide Interactions Revealed by Binding Affinities between Homogeneous Oligopeptides and Single-Stranded DNA Molecules

We have determined the binding strengths between nucleotides of adenine, thymine, guanine and cytosine in homogeneous single stranded DNAs and homo-octapeptides consisting of 20 common amino acids. We use a bead-based fluorescence assay for these measurements in which octapeptides are immobilized on the bead surface and ssDNAs are in solutions. Comparative analyses of the distribution of the binding energies reveal unique binding strength patterns assignable to each DNA nucleotide and amino acid originating from the chemical structures. Pronounced favorable (such as Arg-G, etc.) and unfavorable (such as Ile-T, etc.) binding interactions can be identified in selected groups of amino acid and nucleotide pairs that could provide basis to elucidate energetics of amino-acid-nucleotide interactions. Such interaction selectivity, specificity and polymorphism establish the contributions from DNA backbone, DNA bases, as well as main chain and side chain of the amino acids.     

超高能量电子辐照氮掺杂金刚石的光致发光研究

利用低温光致发光光谱研究了MeV超高能量电子辐照氮掺杂金刚石,结果表明,辐照缺陷以氮-空位缺陷(NV)和中性单空位缺陷(GR1)为主;辐照电子经1.2 mm铝箔遮挡后,其能量大幅度衰减,金刚石中只剩余了NV缺陷,这表明此时辐照产生的空位都被氮杂质所束缚而以NV缺陷形式存在;经800℃高温退火后,空位扩散到晶体表面以下约15μm处而被氮杂质束缚,进而使得GR1信号减弱而NV信号增强.     

不同变性淀粉对麻糬面包品质的影响

为了探索并优化麻糬面包的配方,研究了预糊化乙酰化双淀粉己二酸酯分别与羟丙基二淀粉磷酸酯、乙酰化双淀粉和磷酸酯双淀粉的不同复配比例对麻糬面团的流变特性、微观结构,以及麻糬面包的比容、感官评价与质构特性的影响。结果表明,随着预糊化淀粉添加量的增加,麻糬面包的储能模量与损耗模量升高,初始模量最高分别超过12 500 Pa和4 000 Pa。羟丙基变性淀粉与磷酸酯变性淀粉组中预糊化淀粉添加量增加,麻糬面包的硬度升高到7 571.47 g和6 017.17 g,咀嚼度升高到2 435.48和2 840.05,但是比容逐渐降低,微观结构变的更清晰。而乙酰化变性淀粉组中预糊化淀粉含量升高,麻糬面包的硬度与咀嚼性先下降后上升,比容先上升后下降。当预糊化淀粉添加量为20%时,麻糬面包的感官评分最高,达到86.25分。该研究结果可为麻糬面包的原料提供更多选择,为其加工提供理论依据。