稳定的复数域上状态反馈系统的几何结构

从信息几何的角度使用新的方法研究稳定的复数域上的状态反馈增益系统. 首先, 给出所有稳定的状态反馈增益集合的参数化. 进而,可知稳定的状态反馈增益集合微分同胚于满足一定代数条件的正定Hermite矩阵和反Hermite矩阵的笛卡尔积;其次, 探讨稳定矩阵中稳定的状态反馈增益系统的几何结构;然后,给出状态反馈增益的一个浸入;最后, 举例说明结果.      

Bioactivity analysis of the Ta (V) doped SiO2–CaO–Na2O–P2O5 ceramics prepared by solid state sintering method

The main objective of the study was to control the degradation rate of material at a higher degradation rate improving the chemical stability of the material. Ta is known to have good chemical resistance, biocompatibility and show no adverse biological response. In the present study, SiO2–Na2O–CaO–P2O5 bioceramics with different Ta2O5 contents was prepared by solid state sintering method at 1000 °C. The as-sintered ceramics were subjected to immersion studies in stimulated body fluid (SBF) for 21 days under static condition and characterized by XRD, FTIR, SEM, and AAS. The findings of the research indicate that the addition of Ta2O5 controlled degradability, and all samples showed sufficient bioactivity.     

阳离子淀粉CST制备及脱色性能研究

研究了在基本干的反应条件下制备阳离子淀粉的方法及其脱色性能,确定了用氢氧化钠作催化剂时的最佳反应条件。     

A thyromimetic that decreases plasma cholesterol levels without increasing cardiac activity

A number of agents that mimic the ability of the thyroid hormone, T3, to decrease plasma cholesterol levels are described; one is as effective as T3 at reducing cholesterol levels and stimulating liver function, but has very little effect on cardiac function and is thus less likely to be toxic. The agent may be useful in the treatment of atherosclerosis.     

Size-manipulat ion, compacti on and electrical properties of barium manganite nanorods synthesized via the CHM method

A composite-hydroxide mediated method was employed to synthesize barium manganite nanorods.Diameter,surface smoothness and uniformity of these nanorods were optimized by varying reaction temperature and reaction time.The rods with an average diameter of 200 nm and length of1–1.5 μm were obtained at optimum conditions of 200 1C/48 h.The dielectric study of these rods reveals that they have higher value of dielectric constant at lower frequencies which was attributed to the interfacial and rotational type polarizations.Similarly,the increase in dielectric constant with temperature was attributed to the thermal activation of such polarizations.Furthermore,the analysis of ln(J) vs.E1/2characteristics in the temperature range of 300–400 K shows that possible operative conduction mechanism was of Poole–Frenkel type.The value of βexp was found to be 4.85 times greater than the expected theoretical value of feld lowering coeffcient with an internal feld enhancement factor ofα2 23.5.This high value of βexp may be due to some localized electric felds existing inside the sample.     

Plant genetics: increased outcrossing in hothead mutants

Arising from: S. J. Lolle, J. L. Victor, J. M. Young & R. E. Pruitt 434, 505-509 (2005); Lolle et al. reply. Lolle et al. report that loss-of-function alleles of the HOTHEAD (HTH) gene in Arabidopsis thaliana are genetically unstable, giving rise to wild-type revertants. On the basis of the reversion of many other genetic markers in hth plants, they suggested a model in which a cache of extragenomic information could cause genes to revert to the genotype of previous generations. In our attempts to reproduce this phenomenon, we discovered that hth mutants show a marked tendency to outcross (unlike wild-type A. thaliana, which is almost exclusively self-fertilizing). Moreover, when hth plants are grown in isolation, their genetic inheritance is completely stable. These results may provide an alternative explanation for the genome wide non-mendelian inheritance reported by Lolle et al.     

Structural and optical properties of Zn1−xNixTe thin films prepared by electron beam evaporation technique

Zn1-xNixTe thin films with different composition(x=0.0, 0.05, 0.10, 0.15 and 0.20) were deposited on glass substrate by electron beam evaporation technique followed by its characterization using advanced structural and optical analysis techniques. Structural properties of the prepared thin films were studied by X-ray diffraction(XRD). The XRD patterns revealed that the binary compounds transformed into a ternary compound with cubic structure having preferred orientation along the c-direction with(111) planes. Composition analysis of the films was determined by energy dispersive analysis of X-rays(EDAX) and found to be in agreement with the precursor composition. Optical properties such as extinction coefficient(k) and band gap energy of these films were examined by using a spectroscopic ellipsometer. It was found that the extinction coefficient(k) increased with the addition of Ni content in the alloy. In comparison, the band gap energy was also determined by using transmission spectra and found to be agreed with that of the ellipsometric results. These analyses confirm that the band gap energy decreases with the increase of Ni content in the alloy.     

Perspectives on the prevention and treatment of infection for orthopedic tissue engineering applications

The emergence of orthopedic tissue engineering devices as viable clinical solutions demands that the field address significant clinical complications associated with the implantation of foreign materials in the body, especially infection. While tissue engi- neering has focused on the development of methods to regenerate and repair, until recently there has been a relative dearth of literature regarding the intersection of tissue engineering and infection. In particular, local delivery of antimicrobials has long been of clinical interest, but only recently has that been translated into the realm of tissue engineering. In this perspective, we briefly review major modes of local delivery for infection prevention and treatment and discuss possible strategies for preventing implant-associated infections.     

Zr-pillared montmoril lonite supported cobalt nanoparticles for Fischer – Tropsch synthesis

In this article Fischer–Tropsch(FT) synthesis was studied over cobalt nanoparticles supported on modifed Montmorillonite(Zr-PILC).Co-loaded/Zr-PILC catalysts were synthesized by hydrothermal methods and were characterized by XRD,XRF,BET,H2-TPR,TGA and SEM techniques.FT reactions were carried out in fxed bed microreactor(T 225 1C,260 1C and 275 1C,P 1,5 and 10 bars).The FT-products obtained over Co-loaded/Zr-PILC catalysts showed increased selectivity of C2–C12hydrocarbons and decreased selectivity towards CH4and higher molecular weight hydrocarbons(C21) at a TOS of 2–30 h as compared to the Co-loaded/NaMMT catalysts.With increase in reaction temperature from225 1C to 275 1C,CO-conversion and CH4selectivity increases while that of C5+hydrocarbons decreases.Decrease in CH4selectivity while increase in C5+hydrocarbons and CO-conversion were observed on increasing the pressure of reaction.     

Overexpression of rice OsLOL2 gene confers disease resistance in tobacco to Pseudomonas syringae pv. Tabaci

LSD1-related proteins of Arabidopsis with LSDl-like zinc finger domains regulate disease resistance and programmed cell death （PCD）. We cloned a rice OsLOL2 gene, orthologous to LSD1 of Arabidopsis and expressed it in a tobacco plant. Transgenic tobacco lines displayed enhanced disease resistance to a virulent bacterium Pseudomonas syringae pv. tabaci （Pst）. RT-PCR analysis showed that overexpression of OsLOL2 in transgenic tobacco lines resulted in upregulation of two pathogenesis-related （PR） protein genes, PR2 and PR5. Our results suggest that overexpression of OsLOL2 in transgenic tobacco enhances the resistance through the induction of PR proteins and hypersensitive response-like reaction.