Effect of molasses binder on the physical and mechanical properties

Molasses was used as an alternative binder to the bentonite binder. The change in moisture absorption by pellets prepared with different iron ores and different molasses contents were investigated. Iron ore properties exerted the major effect on pellet behavior and final pellet quality. The absorbed moisture content of pellets prepared without binder, bentonite-added pellets, and molasses-added pellets were in the range of 7.72%–9.95%, 9.62%–10.84%, and 6.14%-6.69%, respectively. The wet pellet compressive strength of molasses-added pellets(43–230 N/pellet) was superior to that of bentonite-added pellets(9.47–11.92 N/pellet). The compressive strength of dried molasses-modified pellets increased to 222–394 N/pellet, which is currently the highest value achieved for dried pellets.     

Effect of nitrogen doping on structural and optical properties of ZnO nanoparticles

Infl uence of nitrogen doping on structural and optical properties of ZnO nanoparticles has been studied. Undoped and N doped ZnO nanoparticles were synthesized via chemical precipitation approach. The prepared samples were characterized through X-ray diffraction(XRD),Transmission electron microscopy(TEM) equipped with Energy dispersive X-ray(EDAX) spectroscopy, UV–visible spectroscopy, Fourier transform infrared(FTIR) spectroscopy and micro-Raman spectroscopy(m RS). Wurtzite phase of undoped as well as 0.5–10% N doped ZnO nanoparticles was con fi rmed through characteristic XRD patterns. The particle size expansion due to N incorporation in ZnO was further revealed by TEM and EDAX analysis where 11 nm size undoped and 18–22 nm size 0.5–10% N doped ZnO(N:ZnO) nanoparticles without any impurity were ascertained. Slight blue-shift in band gap energy, as observed in our case, symbolized weak quantum con fi nement of the prepared nanoparticles. The alterations in vibrational modes of ZnO due to N incorporation, remarkably H substituting at O site and subsequently causing the passivation in N:ZnO nanoparticles, were detected through FTIR analysis. Finally, the effect of the nano-size of crystallite and gradual prominence of N into ZnO lattice due to increase of N doping concentration in prepared nanoparticles was meticulously expatiated though m RS analysis.     

基于卷积编码的SOC测试响应压缩研究

提出一种单输出压缩方法. 首先提出了码率为n/（n-1）、距离为3的卷积码的设计规则, 利用这些规则可得到卷积码的校验矩阵, 该校验矩阵的实现电路即是能够提供单输出压缩的响应压缩电路. 所设计的压缩电路可避免2个和任意奇数个错误位的混淆、避免一个未知位（X位）对特征的掩盖. 利用概率论分析了未知位掩盖效应. 如果未知位分布具有聚簇特征, 那么提出的多重量校验矩阵设计算法能够大大降低未知位的掩盖效应. 最后用一些实验数据验证了所提出的压缩电路能够提供较强的未知位容忍能力和非常低的错误位混淆率.     

Cyclosporin A inhibits activation-induced cell death in T-cell hybridomas and thymocytes

One mechanism by which the immune system develops the ability to discriminate self from nonself is the deletion of autoreactive T-cell clones during thymic maturation. The drug cyclosporin A (CsA) has been shown to interfere with this process, allowing the escape of normally 'forbidden' T-cell clones and the appearance of autoimmune disease. Recently, it has been demonstrated that immature thymocytes undergo programmed cell death (apoptosis) upon activation via the T-cell receptor. A similar phenomenon of activation-induced cell death (AICD) has been observed in T-cell hybridomas. Here we show that AICD in T-cell hybridomas in vitro and in thymocytes in vivo is blocked by CsA. Thus, clonal deletion may involve AICD when self-reactive, immature T cells are induced by self antigen, and CsA may cause autoimmunity by interfering with this process.     

A collimated, high-speed outflow from the dying star V Hydrae

Stars with masses in the range 1-8 solar masses (M(\circ)) live ordinary lives for approximately 10(9)-10(10) years, but die extraordinary deaths. First, during their death throes as asymptotic giant branch (AGB) stars they eject, over 10(4)-10(5) years, half or more of their mass in slowly expanding, spherical winds, and then, in a short (a few 100-1,000 years) and poorly understood phase, they are transformed into aspherical planetary nebula. Recent studies support the idea that high-speed, jet-like flows play a crucial role in this transformation. Evidence for such outflows is indirect, however; this phase is so short that few nearby stars are likely to be caught in the act. Here we report the discovery of a newly launched, high-speed jet-like outflow in the nearby AGB star, V Hydrae. We have detected both proper motions and ongoing evolution in the jet. These results support a model in which the jet is driven by an accretion disk around an unseen, compact companion. We also find a central, dense equatorial disk-like structure which may enable and/or enhance the formation of the accretion disk.