Theory of Digitized Conjugate Surface and Solution to Conjugate Surface

In order to meet the needs of designing and processing digitized surfaces,the method to spreading digitized surface has been proposed.The key technique is to solve the problem of digitized conjugate surface.In the paper,the digitized conjugate surface was theoretically investigated,and the solution of conjugate surface based on digitized surface was also studied.The digitized conjugate surface theory was then proposed,and applied to build the model of solving conjugate surface based on digitized surface.A corresponding algorithm was developed.This paper applies the software Conjugater1.0 that is developed by ourselves to compute the digitized conjugate surfaces of the drum-tooth surface.This study provides theoretical and technical bases for analyzing engagement of digitized surface,simulation and numerical processing technique.     

Surface quality of cold rolling aluminum strips under lubrication condition

The effects of oil film on the rolled surface, including surface roughness and topography, were investigated during cold rolling of aluminum strips. Various mineral oils with viscosities from 0.10 to 1.6 Pa.s were used to obtain different oil film thicknesses. Results from experiment and calculation show that the thicker oil film protects the initial roughening surface so that it leads to an increase in roughness of the rolled surface, in particular when the surface roughness has the character of direction. The rolled surface roughness was determined by λ, which is the ratio of oil film thickness to the combined surface roughness. When λ > 3, the rolled surface roughness increases rapidly with the increase in oil viscosity, whereas the surface roughening has already occurred when λ < 3, but the increase of the rolled surface roughness with increasing viscosity is not distinct.     

Covalent electron density analysis and surface energy calculation of gold with the empirical electron surface model

Based on the empirical electron surface model (EESM), the covalent electron density of dangling bonds (CEDDB) was calculated for various crystal planes of gold, and the surface energy was calculated further. Calculation results show that CEDDB has a great influence on the surface energy of various index surfaces and the anisotropy of the surface. The calculated surface energy is in agreement with experimental and other theoretical values. The calculated surface energy of the close-packed (111) surface has the lowest surface energy, which agrees with the theoretical prediction. Also, it is found that the spatial distribution of covalent bonds has a great influence on the surface energy of various index surfaces. Therefore, CEDDB should be a suitable parameter to describe and quantify the dangling bonds and surface energy of various crystal surfaces.     

Three-year changes of surface albedo of degraded grassland and cropland surfaces in a semiarid area

Diurnal, seasonal and interannual variations of surface albedo of degraded grassland and cropland surfaces at a semiarid area of Tognyu have been investigated based on the continuous three years observational data from 2003 to 2005. The changes of surface albedo with solar elevation angle and soil moisture have been discussed also. It has been found that surface albedo has almost the same diurnal and seasonal variations on degraded grassland and cropland surfaces in the semiarid area, while surface albedo is large in winter and small in summer. The diurnal variation of the surface albedo has relationship with the weather condition. The diurnal cycle of the surface albedo likes the ＂U＂ shape curve in sunny day, while it is low-high after the rain, and high-low after the snow. The surface albedo has large variation in cloudy day, while it has no any variation in overcast day. The large difference of the surface albedo can be 0.04 in winter between two land surfaces, because the snow has large effects on the surface albedo in winter. The rainfall is an important factor in summer on the surface albedo, while the difference of the surface albedo is 0.01 only between two land surfaces. The differences of the surface albedo can also be 0.04 in autumn due to vegetation growing. The seasonal-average surface albeo from 2003-2005 is 0.25, 0.22, 0.24, 0.32 respectively in spring, summer, autumn and winter on the degraded grassland surface, while it is 0.25, 0.21,0.22, 0.33 respectively in spring, summer, autumn and winter on the cropland surface. The surface albedo becomes smaller with the increase of solar elevation angle. When the solar elevation angle is greater than 40°, the surface albedo changes very little and tends to be a constant. The surface albedo has negative exponent functions with soil moisture in the growing season.     

Surface study of the reconstructed anatase TiO_2(001) surface

The anatase TiO_2(001) surface has attracted extensive attention in surface science and for practical applications because of its excellent performance. However, the highly reactive(001) surface usually reconstructs to a(1 ×4)-(001) surface, which may potentially alter its properties. As a result, there are still controversial issues concerning the intrinsic performance of this surface. Recently, significant advances have been made in the surface science study of TiO_2(001), which have elucidated its intrinsic physical and chemical properties. In this review,we summarize our present understanding of the structure and properties of the reconstructed TiO_2(001) surface.First, we provide a brief background of the anatase TiO_2 surfaces, including its low-index surface structures and the synthesis of anatase TiO_2 nanocrystals with the(001) surface exposed. Next, we focus on the structure,formation mechanism, stability, and surface chemistry of the reconstructed TiO_2(001) surface. Finally, we finish this review by highlighting the current challenges of this subject and providing future research perspectives.     

The Surface Properties and Tensile Strength of HSPE Fiber Treated by Controlling Oxidation in Chromic Acid

This work reported on the surface modification of high strength polyethylene(HSPE)fiber by chemical etching in chromic acid.The surface chemistry,the functional group contents, the wetting ability, the surface morphology and the tensile strength of modified fibers were investigated. The results show that, the surface roughness,surface wet properties and active functional group can be introduced on the HSPE fiber surface by this method,which will improve the interface adhesion in the composites, and the decrease of the tensile strength of modified fibers can be controlled.     

Effects of Electrochemical Treatment on the Superficial Properties of Rayon-based Carbon Fibers

The development of surface acidity on rayon-based carbon fibers during mild electrochemical treatment was investigated. Conductimetric titration was the primary method used to investigate the functionalities on the carbon fiber surface. The acidity on the surface of the untreated carbon fiber was very low, while for the treated fibers, the acidity increased significantly. Moreover, with the treatment extent proceeded, the acidity on the fiber surface also increased. SEM analysis shows electrochemical treatment under intense treatment degree caused considerable etch on the fiber surface. Cavities and grooves can be observed on the surface via the SEM microphotograph. While in a more mild treatment, electrochemical treatment didn't cause great etch on the surface of the fiber.     

SKINNING MODELLING OF THE HUMAN BODY BASED ON NON-UNIFORM B-SPLINE

This paper describes the surface modelling method of the human body based on non-uniform B-spline. Tensor-product form of B-spline surface is employed in computation of surface interpolation. It is efficient to reduce the raw data of the human body captured from 3D surface scanner. The surface model acquired provides a coherent representation to the raw data, therefore is useful for 3D computer-aided clothing design.     

First-principle study on the surface atomic relaxation properties of sphalerite

The surface properties of sphalerite (ZnS) were theoretically investigated using first principle calculations based on the density functional theory (DFT). DFT results indicate that both the (110) and the (220) surfaces of sphalerite undergo surface atom relaxation after geometry optimization, which results in a considerable distortion of the surface region. In the normal direction, i.e., perpendicular to the surface, S atoms in the first surface layer move outward from the bulk (d₁), whereas Zn atoms move toward the bulk (d₂), forming an S-enriched surface. The values of these displacements are 0.003 nm for d₁ and 0.021 nm for d₂ on the (110) surface, and 0.002 nm for d₁ and 0.011 nm for d₂ on the (220) surface. Such a relaxation process is visually interpreted through the qualitative analysis of molecular mechanics. X-ray photoelectron spectroscopic (XPS) analysis provides the evidence for the S-enriched surface. A polysulphide (S_n2-) surface layer with a binding energy of 163.21 eV is formed on the surface of sphalerite after its grinding under ambient atmosphere. This S-enriched surface and the S_n2- surface layer have important influence on the flotation properties of sphalerite.     

Some inequalities for geominimal surface areas

The concept of geominimal surface area is first intro- duced, and then, the affine surface area projection inequality is given by Petty. In recent years, associated with geominimal surface area, Lutwak obtained some significant results containing the extended affine projection inequality. In this paper, combining with curvature image and combinations of convex bodies, we get some inequalities for geominimal surface areas. Furthermore, the integral form of geominimal surface area is obtained.     

Plasmonic coupling in single flower-like gold nanoparticle assemblies

Localized surface plasmon resonance (LSPR) arises when light interacts with metallic nanoparticles (NPs). When nanoparticles (NPs) assemble together, the plasmon coupling effect between the NPs often leads to new features in the LSPR of the assembled structure. Understanding the plasmon coupling in the complex assemblies will greatly benefit the development of new plasmonic devices. Here we demonstrate the fabrication of a 3D structure using two different sized Au NPs as building blocks. This 3D structure was achieved by manipulating the binding efficiency of ligands linking the NPs, and proper choice of the NP size. The assembled structure is flower-like structure, with one 130 nm Au NP in the center, and several 40 nm Au NPs attaching as “petals”. Single particle dark-field scattering measurements of the individual assemblies were performed, together with electrodynamics simulations. The experimental and theoretical studies show that, the plasmonic coupling lead to broadening of the LSPR and additional peaks, depending on the number and 3D arrangement of the 40 nm NPs around the center 130 nm NP.     

Aqueous controllable synthesis of spindle-like palladium nanoparticles and their application for catalytic reduction of 4-nitrophenol

In this study, an effective wet-chemical route was developed in an aqueous solution for the synthesis of spindle-like palladium nanoparticles (Pd NPs). Spindle-like Pd NPs in high-yield were successfully synthesized by using cetyltrimethylammonium chloride (CTAC) as surfactant and ascorbic acid (AA) as reduction reagent. The influence factors including the concentration of CTAC, AA, and NaI, as well as the reaction temperature for synthesis of spindle-like Pd NPs were systematically investigated. The formation mechanism of spindle-like Pd NPs was proposed on the basis of these experimental results. Spindle-like Pd NPs with high density of twins and sharp edges exhibit enhanced catalytic activities for the reduction of 4-nitrophenol.     

退火气氛对ZnO纳米颗粒的结构及发光特性的影响

在500℃且不同退火气氛(氮气、氧气)条件下,我们通过化学沉淀法成功制备了ZnO纳米颗粒.采用X射线衍射仪(XRD)、透射电子显微镜(TEM)、光致发光(PL)和拉曼光谱(Raman)研究退火气氛对ZnO纳米颗粒结构和发光特性的影响.实验结果表明,制得样品为具有六角纤锌矿结构的ZnO.从Raman和PL光谱可以观测到,退火气氛对ZnO纳米颗粒的结晶和发光特性都有很大的影响,氮气气氛下退火得到样品发光特性较好,缺陷较少,文中对其影响机制进行了讨论.     

Au NPs decorated TiO2 nanotubes array candidate for UV photodetectors

This work reports the Au nanoparticles (NPs) deposited on TiO2 nanotubes (NTs) which were successfully synthesized by a simple two-step anodization method. This fabrication process is notable for a simple and inexpensive method for obtaining pure TiO2 NTs and Au NPs deposited TiO2 NTs. The prepared samples were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and I-V curve. We found that the size of Au NPs can be controlled by changing the bias voltage during the deposition. The photodetectors of Au NPs/TiO2 devices showed good wavelength selectivity with high photocurrent as compared to pure TiO2 NTs devices. Subsequently, Au NPs deposited on TiO2 NTs at bias voltage of 70 V was potentially used in fabrication of UV photodetector. At this applied voltage, a high density of Au NPs was uniformly deposited on TiO2 NTs. As a result, it enables a high photocurrent and great responsivity in UV region. It is suggested that the Au NPs deposited TiO2 NTs device shows good promise for UV photodetectors with possibility to fine-tune properties in both UV and visible regions and is worthy of further investigation.     

Reactive incorporation of Ag into porous TiO_2 coating and its influence on its microstructure,in vitro antibacterial efficacy and cytocompatibility

Ag-doped TiO_2 coatings were successfully fabricated on Ti using plasma electrolytic oxidation(PEO) in the electrolytes containing Ag or Ag_2O nanoparticles(NPs). The results showed that the different Ag sources resulted in significant variations of morphology, composition and chemical state. The thermal decomposition of Ag_2O during PEO process contributed to the formation of Ag NPs, which might reactively incorporate into TiO_2, leading to the presence of a Ca, P-rich amorphous layer between entrapped Ag NPs and the peripheral TiO_2. By contrast,Ag specie tends to be present as micro-sized clusters consisting of metallic Ag NPs in the PEO coating fabricated via Ag NPs addition. The different microstructures inevitably affected the Ag ionic release behaviour and thus antibacterial capabilities and cytocompatibilities. It is indicated that the application of Ag_2O NPs as Ag source is promising to fabricate Ag-doped PEO coating with both long-term antibacterial activity and acceptable cytocompatibility.     

Ag@Pt核壳结构纳米粒子催化剂在电催化过程中的失效分析

通过种子生长法和自组装技术合成Ag@Pt核壳结构纳米粒子(以下简称Ag@Pt粒子),测量和比较在电催化循环伏安扫描(以下简称CV扫描)过程中失效前后的Ag@Pt粒子对甲醇的电催化性能的变化,采用透射电镜、高分辨电镜、X射线光电子能谱等方法研究其失效机理.结果表明：Ag@Pt粒子在循环伏安扫描的过程中会发生空化现象,其临界电压为0.5 V,空化现象随时间的增长而变得明显;Ag@Pt粒子空化后形成由Ag包覆空心Pt壳的纳米粒子,这是导致其在对甲醇进行电催化氧化过程中催化性能明显下降的原因.     

金/二氧化硅中空核壳纳米球的制备与表征

采用水热反应法和正硅酸乙酯水解法制备出核壳结构的Au/C纳米球颗粒以及夹层结构的Au/C/SiO<,2>纳米球颗粒,在空气中锻烧将Au/C/SiO<,2>夹层结构中的碳层除去,得到内部带有可移动纳米金核、壳层厚度约为20 nM的中空Au/SiO<,2>纳米球颗粒.用透射电子显微镜对所制得的纳米微球的形貌进行表征,并用红...     

基于壳聚糖载体的蛋白质药物纳米颗粒制备研究

采用基于壳聚糖(CS)与聚阴离子(多聚磷酸纳)间静电作用的离子凝胶化方法,以牛血清白蛋白(BSA)为模型,在室温下制备了包载蛋白质的亲水性壳聚糖纳米颗粒.对BSA-壳聚糖纳米颗粒的形成条件进行了考察,结果表明:在pH值为5.0,CS与TPP的质量比为4,壳聚糖分子量为40 kDa的最优化的条件下可制备粒径小于100 nm的BSA-壳聚糖纳米颗粒,对BSA的包封率达到50%以上.并将该体系初步应用于蛋白类药物丙种球蛋白-壳聚糖纳米颗粒的制备研究,这种壳聚糖纳米颗粒对丙种球蛋白具有良好的缓释作用.     

A facile and general approach for the synthesis of fluorescent silica nanoparticles doped with inert dyes

A general and facile approach was developed for the synthesis of almost monodisperse fluorescent silica nanoparticles (NPs) doped with inert dyes, which are organic fluorophores that are strongly fluorescent but are hydrophobic or lack a covalent binding group. The prepared NPs were mesoporous and the dye molecules were encapsulated in the pores via hydrophobic interaction with the CTAB template. The NPs were stable and highly fluorescent in aqueous solution, and have potential applications in bioanalysis a...     

金纳米颗粒的摄入对细胞光学性质影响的数值仿真

采用时域有限差分法(FDTD)方法计算了细胞摄入金纳米颗粒后的消光光谱,并对金纳米颗粒在细胞中3种不同的分布做了比较:金纳米颗粒均匀分布细胞膜上;金纳米颗粒在细胞质内均匀分布,不存在于细胞核中;金纳米颗粒在整个细胞中均匀分布.分析结果表明,由于金纳米颗粒的等离子共振效应,细胞在可见光区域的散射截面产生增强,并且其消光光谱的峰形和消光峰的位置也发生相应的变化,这种变化依赖于金纳米颗粒在细胞内的分布情况.当金纳米颗粒在细胞膜上均匀分布的时候,细胞的消光光谱的峰值最大,而另外2种情况则形成较宽的消光峰.计算结果有助进一步理解纳米颗粒在细胞内的扩散或生长的过程.