Production and Storage of Energy with One-Dimensional Semiconductor Nanostructures

This article outlines state-of-the-art energy technologies, including production and storage, available to us through semiconductor nanomaterials. The nanostructure growth processes have been illustrated in detail, with emphasis on the latest developments in hierarchical and radial-composition modulated nanostructures. On the energy efficiency and generation part, light-emitting diodes, photovoltaics, photoelectrochemistry, thermoelectric, and fuel cells have been discussed. In the energy storage part, supercapacitors and lithium batteries have been discussed.     

Hadron mass spectrum from lattice QCD

Finite temperature lattice simulations of quantum chromodynamics (QCD) are sensitive to the hadronic mass spectrum for temperatures below the "critical" temperature T(c) ≈ 160 MeV. We show that a recent precision determination of the QCD trace anomaly shows evidence for the existence of a large number of hadron states beyond those known from experiment. The lattice results are well represented by an exponentially growing mass spectrum up to a temperature T=155 MeV. Using simple parametrizations of the hadron mass spectrum we show how one may estimate the total spectral weight in these yet undermined states.     

SANS investigation on evolution of pore morphology for varying sintering time in porous ceria

Precipitates of ceria were synthesized by homogeneous precipitation method using cerium nitrate and hexamethylenetetramine at 80°C. The precipitates were ground to fine particles of average size ∼0.7 μm. Circular disks with 10 mm diameter, 2 and 3 mm thickness were prepared from the green compacts by sintering at 1300° C for three different sintering times. Evolution of the pore structures in these specimens with sintering time was investigated by small-angle neutron scattering (SANS). The results show that the peak of the pore size distribution shifts towards the larger size with increasing sintering time although the extent of porosity decreases. This indicates that finer pores are eliminated from the system at a faster rate than the coarser ones as sintering proceeds and some of the finer pores coalesce to form bigger ones.     

2-(2-喹啉偶氮)-1,5-苯二酚分光光度法测定烟草样品中的钙

在 p H为 8.0的柠檬酸钠 -氢氧化钠缓冲介质中 ,Triton X- 10 0存在下 ,2 - (2喹啉偶氮 ) - 1,5苯二酚(QADHB)与钙反应生成 1∶ 1稳定配合物 ,λmax=5 5 5 nm,ε=4 .18× 10 4L· mol-1· cm-1。钙含量在 0 .1—2 5μg/ 2 5 m L的范围内符合比耳定律 ,方法用于烟草中钙含量的测定 ,结果令人满意。     

赤铁矿和三羟铝石吸附Cu~(2+)的红外光谱研究

应用红外光谱法,研究了不同pH值和Cu2+浓度条件下,合成赤铁矿和三羟铝石吸附Cu2+后表面羟基结构及其特征吸收峰的变化。结果表明:(1)随Cu2+浓度增加,赤铁矿表面H—O—H和OH的变形振动参与了吸附反应,Cu2+强烈地缔结在Fe—O上,形成了Fe—O—(Cu)结构。(2)酸性条件下,H+破坏了赤铁矿表面的O—H结构,NO3-促使弱峰1 131 cm-1的产生。随pH值增大,赤铁矿表面OH-逐渐由伸缩振动转变为变形振动,Fe—OH和Fe3+—O2-结构不断发生改变。(3)三羟铝石对Cu2+的吸附发生在高波位,随Cu2+浓度增大,其表面游离羟基的O—H弯曲振动、水分子的OH-伸缩振动和H—O—H弯曲振动均参与了吸附反应,Al—O基中的Al3+渐被Cu2+取代从而加强了较低波位的振动强度。(4)随pH值增加,三羟铝石Al—OH的弯曲振动和Al—O的伸缩振动逐渐发生着改变,表明吸附Cu2+后,在其表面形成了AlOCu+与AlOCuOH结构。     

气轨上单摆的混沌实验

设计并自制了一个气轨上单摆的混沌演示装置,建立了系统的动力学方程,直观地显示了混沌的一些基本特征。     

Synthesis of a Novel Flame Retardant and Its Synergistic Effect With a Phosphapheanthrene Flame Retardant in Polypropylene/Polyethylene Vinyl Acetate Blends

A novel flame retardant (NSiB) containing nitrogen, silicon and boron was synthesized through reacting of N-(β-aminoethyl)-γ-aminopropyl trimethoxy-silane (KH-792) and boric acid. The structure of NSiB was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy with energy dispersive spectrometry (SEM-EDS). The effects of NSiB on the flame retardancy and thermal behaviors of polypropylene (PP)/polyethylene vinyl acetate (EVA) blends were investigated by limiting oxygen index value (LOI), vertical burning tests (UL-94) and thermal gravimetric analysis tests (TGA). The results showed that the flame retardancy and thermal stability of PP/EVA blends were improved with the addition of NSiB. When 7.5 wt% DOPO (phosphaphenanthrene) and 0.5 wt% NSiB were incorporated, the LOI value of the PP/EVA blends was 26.9%, and the class V-0 of UL-94 test was passed, as compared to the LOI value of 22.4% and class V-2 of UL-94 test for 8.0 wt% DOPO only and 16.7% and fail, respectively, for the PP/EVA blends alone. The char structure observed by SEM indicated that the surface of the char for the PP/EVA/7.5 wt% DOPO/0.5 wt% NSiB blends had a denser and continuous char structure when compared with that of the PP/EVA blends and PP/EVA/8.0 wt% DOPO blends. These results indicated that there was a good synergistic effect for NSiB and DOPO.     

温度对潜望式激光通信终端SiC反射镜性能影响

分析了温度梯度和均匀温度对潜望式激光通信终端反射镜形变的影响,利用椭圆域上的Zernike多项式对椭圆反射镜的波前进行拟合,计算由于热形变导致的波前畸变误差,给出了星间激光通信终端反射镜均方根值、发射光束瞄准误差、接收端光强随温度梯度和均匀温度的变化关系。结果表明:温度梯度对反射镜的影响只是引起峰值光强的漂移和少许下降,当温度梯度为14 ℃/m时瞄准误差达2.1 μrad。均匀温度会引起接收端的光强分布变化,从而导致很大的瞄准误差和光强衰减,当均匀温度与参考温度的差值小于0.6 ℃时,由波前畸变误差引起的瞄准误差小于1 μrad,当差值大于0.6 ℃时,瞄准误差突然增大到几μrad,接收端光强分布发生变化,此时反射镜热形变引起的像散项对光强分布起重要作用。