Preparation and clinical trial of new dried balanced food products "Unipit" for total restorative nutrition]

Designs of 2 types of dried balanced food mixtures ("Unipit-1" and "Unipit-2") intended for complete recovery nutrition of patients with retained and disordered digestive function have been validated. The chemical composition of these products has been presented. The results of clinical trials have proved the high therapeutic effectiveness of "Unipit-1" and "Unipit-2" in rehabilitation of neurosurgical patients.     

Cation interdiffusion between thick film of YBa2Cu3O7-δ and ceramic substrate

Thick films of superconducting oxides, YBa₂Cu₃O_7-, were successfully made by conventional screen-printing technology on Al₂O₃, MgO, and ZrO₂ substrates. Interdiffusion between the superconductive film and substrate was investigated using analytical electron microscopy. The results indicate that MgO and ZrO₂ are superior to Al₂O₃ for substrate materials.     

Microstructural studies of aluminium-silicon alloy reinforced with alumina fibres

The microstructure of an alumina fibre reinforced Al-7wt% Si alloy has been investigated. It was shown that the Al-Si eutectic structure which characterized this alloy was markedly changed by the presence of the fibres, with coarsening of silicon particles and a reduction in primary aluminium grain size. The coarse silicon particles exhibited twinning but no orientation relationship with the aluminium. Fine silicon precipitates were also present and these had a cube-cube orientation relationship with the aluminium lattice. Lath-like intermetallics, FeSiAl₅ and FeSi₂Al₄ with monoclinic and tetragonal structures, were identified which existed in equilibrium and had the epitaxial relationship (001)_mono//(001)_tet and [100]_mono//[100]_tet. The iron was a contaminant introduced in the course of composite fabrication.Dislocations were a common feature of the aluminium matrix, with a typical density of 4×10⁷mm^–2. Nevertheless, dislocation hardening of the metal matrix was not detected. No evidence of Mg₂Si precipitates in the metal matrix was found, but the small addition (0.2wt%) of magnesium to the alloy was discovered to segregate at the fibre-aluminium interface. This segregation was believed to result in improved wettability of the two constituents, encouraging the formation of a strong fibre-matrix bond, and producing desirable properties of the composite in the transverse direction.     

Synthesis of polycrystalline alumina fibre with aluminium chelate precursor

Polycrystalline alumina fibre was successfully synthesized by pyrolysis of preceramic fibre formed from aluminium chelate compound. Ethyl 3-oxobutanoatodiisopropoxyaluminium (EOPA) was reacted with glacial acetic acid yielding a polymeric product. The absorption bands ascribed to Al-O from 630–705 cm^–1 changed from a sharp to a broad band on treatment with acetic acid. The¹³CNMR spectrum of EOPA changed from sharp singlets to multiplets after the reaction with acetic acid. The viscosity of the polymeric product increased in intensity with increasing amount of acetic acid. The viscosity of the polymeric product formed from EOPA-30 mol % acetic acid was 450 Pa s at 30 °C, and decreased to 5.4 Pa s with increasing measurement temperature from 30–70 °C. The²⁷Al resonance at 35 p.p.m. increased in intensity with increasing viscosity of the polymeric precursor. The molecular weight of the precursor was distributed from 400–800. The polymeric precursor pyrolysed at 500 °C in air was amorphous to X-rays, and crystallized in -alumina at 840 °C. The precursor fibres were pyrolysed, to yield fine-grained fibres of -alumina, at 1300 °C for 1 h.     

The formation of β′-sialon from a montmorillonite-polyacrylonitrile composite by carbothermal reduction: an NMR,TGA, XRD and EM study

The products of carbothermal reduction in N₂ of a nanocomposite between dodecylammonium-exchanged montmorillonite and polyacrylonitrile (PAN) have been studied by solid-state ²⁷Al and ²⁹SiNMR spectroscopy, X-ray diffraction, transmission electron microscopy and thermogravimetry. Comparison with analogous reactions involving sodium-exchanged montmorillonite and dodecylammonium-exchanged montmorillonite (without PAN) shows that in the presence of PAN, the formation of silica, cordierite or mullite is almost completely suppressed. The only crystalline phase detected between 1000 and 1300 °C was a -sialon, having a much higher SiAl ratio (7.051) than that of the precursor clay (2.441). Reduction of the octahedral AlO₆ begins near 1200 °C, forming increasing amounts of Al(N,O)₄ tetrahedra with temperature, so that by 1600 °C, complete reduction to AlN₄ (i.e. bulk AlN) has occurred. In contrast, reduction of the tetrahedral SiO₄ is appreciable at 1100 °C, and is almost complete (SiN₄ tetrahedra only) by 1200 °C. No intermediate Si(N,0)₄ environments are found. By 1600 °C, only the SiC₄ environment (i.e. bulk SiC) remains. A mechanism is suggested, involving the formation of alternating slabs of an amorphous aluminosilicate and carbon at 1000 °C, followed by diffusion of silicon from the outer regions of the aluminosilicate band towards the centre, and sequential reduction of Si(OSi)₄ and Si(OSi)₃ (OAl) groups.     

Structure of nickel-doped α-FeOOH

Colloidal particles of nickel-doped-FeOOH prepared under varied conditions were characterized using transmission electron microscopy, X-ray diffraction thermogravimetry-differential thermal analysis, Fourier transform infrared analysis, inductively coupled plasma spectroscopy and nitrogen adsorption. The unit cell dimensions of the resulting-FeOOH slightly changed on doping with nickel. Both the total and surface hydroxyl ions decreased with increasing amounts of nickel. The nickel content in the surface layer determined by X-ray photoelectron spectroscopy was larger than the total nickel content determined by inductively coupled plasma spectroscopy. The results obtained indicate that the substitution of iron with nickel took place in the surface layer more than in the internal phase.     

卡尔曼滤波算法在MEMS热式风速风向传感器中的应用

针对MEMS热式风速风向传感器在实际使用过程中因噪声问题导致输出不稳定的现象,本文首次采用了卡尔曼(Kalman)滤波算法对本征白噪声进行滤波处理,从而优化传感器的输出性能.本文分别通过理论分析和仿真模拟证明了Kalman滤波算法的可行性.实验结果表明,通过调节相关参数,Kalman滤波算法在滤波效果、响应速度及误差上均优于传统的加权滑动均值滤波算法.除此之外,在消耗较少资源的前提下,Kalman滤波算法可以有效减少本征白噪声的干扰,且调节空间较大,可以适应不同的应用需求.     

物流中心选址问题的二元语义决策方法

为了有效避免语言评价中信息的损失和扭曲,从而提高物流中心选址的准确性,在层次分析法中引入三角模糊数,将各评价指标量化,提出一种二元语义决策选址方法.给出二元语义评价的方法与步骤,并通过物流中心选址的算例分析说明该方法的合理性.     

基于不完全信道信息的D2D功率分配算法

针对蜂窝与终端直通(Device-to-device,D2D)混合网络中的不完全信道状态信息(Channel state information,CSI),提出了一种基于不完全CSI的最优功率分配算法。利用拉格朗日乘数法推导出了最优功率分配解的闭式表达式。相对于传统的最大发送功率分配方案,该最优解受信道信息误差的影响较小,具有较好的鲁棒性。仿真结果表明,本文算法可以节约发送功率,并得到更大的接收信噪比。     

Influence of static pre-loading on the dynamic bending strength of concrete with particle element modeling

Experimental tests show that static pre-loading has a significant effect on the dynamic strength of concrete.Based on meso-scale particle element model,numerical simulations of dynamic bending tests with pre-loading are performed.Complete stress–strain relationships are then obtained.Significant increase in dynamic strength is found when the pre-loadings are imposed within the elastic limit of concrete.However,when the imposition of pre-loadings reaches the plastic or softening range,dynamic strengths may gradually decrease along with the increase in pre-loadings.The distribution of energy components and the failure modes are discussed to explain the mechanisms of the phenomena.