嵌入式Linux混合文件系统的设计与分析

嵌入式Linux系统必须达到性能和空间的优化.文章对嵌入式Linux进行了耗时分析,根据系统对根文件目录操作中耗时问题设计了嵌入式Linux混合文件系统,并与常见单一文件系统在启动速度和程序运行速度上对其进行了仿真测试.数据证明混合型文件系统不仅占用空间较小,并且能提高系统的性能.     

QuatJND: A Robust Quaternion JND Model for Color Image Watermarking

Robust quantization watermarking with perceptual JND model has made a great success for image copyright protection. Generally, either restores each color channel separately or processes the vector representation from three color channels with the traditional monochromatic model. And it cannot make full use of the high correlation among RGB channels. In this paper, we proposed a robust quaternion JND Model for color image watermarking (QuatJND). In contrast to the existing perceptual JND models, the advantage of QuatJND is that it can integrate quaternion representation domain and colorfulness simultaneously, and QuatJND incorporates the pattern guided contrast masking effect in quaternion domain. On the other hand, in order to efficiently utilize the color information, we further develop a robust quantization watermarking framework using the color properties of the quaternion DCT coefficients in QuatJND. And the quantization steps of each quaternion DCT block in the scheme are optimal. Experimental results show that our method has a good performance in term of robustness with better visual quality.     

场发射锥尖的制备及特性研究

研究了倒金字塔填充型锥尖及正向刻蚀硅尖的制备工艺,采用了两种封装结构测试了场发射硅尖阵列的发射特性,并分析比较了这两种结构的特点及用于制备高频微波器件的可能性。     

Sustainable and Robust Graphene Cellulose Paper Decorated with Lithiophilic Au Nanoparticles to Enable Dendrite-free and High-Power Lithium Metal Anode

Lithium metal anodes (LMAs) with high energy density have recently captured increasing attention for development of next-generation batteries. However, practical viability of LMAs is hindered by the uncontrolled Li dendrite growth and infinite dimension change. Even though constructing 3D conductive skeleton has been regarded as a reliable strategy to prepare stable and low volume stress LMAs, engineering the renewable and lithiophilic conductive scaffold is still a challenge. Herein, a robust conductive scaffold derived from renewable cellulose paper, which is coated with reduced graphene oxide and decorated with lithiophilic Au nanoparticles, is engineered for LMAs. The graphene cellulose fibres with high surface area can reduce the local current density, while the well-dispersed Au nanoparticles can serve as lithiophilic nanoseeds to lower the nucleation overpotential of Li plating. The coupled relationship can guarantee uniform Li nucleation and unique spherical Li growth into 3D carbon matrix. Moreover, the natural cellulose paper possesses outstanding mechanical strength to tolerate the volume stress. In virtue of the modulated deposition behaviour and near-zero volume change, the hybrid LMAs can achieve reversible Li plating/stripping even at an ultrahigh current density of 10 mA cm⁻² as evidenced by high Coulombic efficiency (97.2 % after 60 cycles) and ultralong lifespan (1000 cycles) together with ultralow overpotential (25 mV). Therefore, this strategy sheds light on a scalable approach to multiscale design versatile Li host, promising highly stable Li metal batteries to be feasible and practical.     

Durable antimicrobial cotton fabric fabricated by carboxymethyl chitosan and quaternary ammonium salts

Cellulose - In this article, carboxymethyl chitosan (CMC) and (3-carboxypropyl) trimethylammonium chloride (CPTC) were used as raw materials to prepare an antibacterial cotton fabric with excellent...     

RF化学气相淀积金刚石薄膜

本文论述了金刚石薄膜的优点，比较了化学淀积金刚石薄膜的常用方法的优缺点，主要介绍了电容耦合射频化学气相淀积金刚石薄膜的原理和近期国际对典型电容耦合气相淀积设备的改进研究。     

Formylferrocenyl-3-hydroxyl-2-naphthoylhydrazone and its transition metal complexes

Summary Formylferrocenyl-3-hydroxyl-2-naphthoylhydrazone and its transition metal coordination compounds have been synthesized and characterized by elemental analyses, i.r., ¹H-n.m.r., u.v.-vis., t.g.-d.t.a. and molar conductivities. The results show that the ligand coordinates to transition metal ions in the enolic form, accompanied by the release of acetate or nitrate.     

纳米硅(nc-Si:H )/晶体硅(c-Si)异质结太阳电池的数值模拟分析

运用美国宾州大学发展的AMPS程序模拟分析了n-型纳米硅（n+-nc-Si:H）/p-型晶体硅(p-c-Si)异质结太阳电池的光伏特性.分析表明，界面缺陷态是决定电池性能的关键因素，显著影响电池的开路电压（VOC）和填充因子（FF），而电池的光谱响应或短路电流密度（JSC）对缓冲层的厚度较为敏感.对不同能带补偿（bandgap offset）的情况所进行的模拟分析表明，随着ΔEc的增大，由于界面态所带来的开路电压和填充因子的减小逐渐被消除，当ΔEc达到05eV左右时界面态的影响几乎完全被掩盖.界面层的其他能带结构特征对器件性能的影响还有待进一步研究.最后计算得到了这种电池理想情况下（无界面态、有背面场、正背面反射率分别为0和1）的理论极限效率ηmax=3117% (AM15，100mW/cm2，040—110μm波段).     

内点算法和动力系统

本文以动力系统的理论统一处理各种解线性规划的内点算法.在一般情况下讨论了此类系统的构成和基本的附加条件.对轨线的几何特征,尤其是它们在靠近边界处的动态作了进一步研究.     

Determination of90Sr and 137Cs concentrations in the IAEA reference material Soil-6

Vezetéknév This revised version was published online in August 2006 with corrections to the Cover Date.