试论营养教育的重点人群

营养教育是健康教育的重要组成部分,是方便、有效的营养干预方式,许多国家都极为重视。我国目前营养教育应当首先关注重点人群,即营养弱势群体和对膳食与营养具有影响力的人群。营养弱势群体主要包括儿童青少年、孕妇乳母、老年人、慢性病患者、社会弱势群体,他们或处在生长发育的关键时期、或处在特殊的生理时期,或是健康状况不良的人群,或是营养状况较差的群体;对膳食与营养具有影响力的人群主要包括家庭主妇、团体膳食制作及管理人员。营养教育应从这些重点人群入手,提高其膳食营养意识,普及基本营养知识,改善大众营养状况,提升生命质量。     

烯基琥珀酸酐表面改性淀粉膜羟基取代度的影响因素

以十二烯基琥珀酸酐和辛烯基琥珀酸酐为酯化剂对淀粉膜进行表面改性,通过正交试验研究了各种因素对淀粉膜表面羟基取代度的综合影响。结果表明,用十二烯基琥珀酸酐表面改性时,影响羟基取代度的最重要因素是酸酐稀释倍数;用辛烯基琥珀酸酐改性时,影响羟基取代度的最主要的因素是平衡环境的湿度;将十二烯基琥珀酸酐和辛烯基琥珀酸酐按不同的比例混合起来对淀粉膜表面改性,影响其羟基取代度的最主要因素是碱溶液质量分数。     

提高自我发展能力是农村弱势群体救助的必然选择

尽管政府对农村弱势群体的救济力度不断加大,却没能从根本上改变其弱势状态.贫困只是农村弱势群体的表象,自我发展能力的缺乏才是本质所在.因此,只有通过提升自我发展能力,让农村弱势群体成员积极主动地融入社会发展之中,才是解决农村弱势问题的根本出路.     

±800kV云广直流输电工程控制保护系统提高可靠性的措施

±800kV云广特高压直流输电工程是西电东送的重要通道,必须确保系统的可靠性。为此,在一次接线上采用了双12脉动阀组接线,使得一个阀组故障时仍可传送一半功率。对应新的接线形式,云广工程控制保护系统的设计从合理的层次结构、功能划分、通信网络结构以及抗干扰措施等多方面进行了综合考虑,提高了系统的可靠性和可用率。     

Preparation of a Novel Class of Cationic Gemini Imidazolium Surfactants Containing Amide Groups as the Spacer: Their Surface Properties and Antimicrobial Activity

A class of novel cationic Gemini imidazolium surfactants containing amide groups as the spacer were synthesized from ethylenediamine and 1-bromoalkane(C₈, C₁₀, C₁₂, C₁₄, C₁₆) by N-alkylation to get N,N′-dialkyl ethylenediamine (1a–e), 1a–e was further reacted with chloroacetyl chloride by N-acylation to get N,N′-(ethane-1,2-diyl)bis(2-chloro-N-alkylacetamide) (2a–e), which was further reacted respectively with 1-methyl imidazole by quaternized to form the surfactant molecule, N,N′-((ethane-1,2-diyl)bis(alkyl-azanediyl)bis(2-oxoethane-2,1-diyl)) bis(1-methyl-1H-imidazol-3-ium) dichloride. The structures of intermediates (1a–e) and (2a–e) were characterized by IR and ¹H NMR. The structures of the surfactants (3a–e) were characterized by IR, ¹H-NMR and ¹³C-NMR and element analysis. The critical micelle concentrations (CMC) of 3a–e were determined by the conductivity method at 25 °C. The CMC values decreased with increasing the length of the hydrophobic chain. The surfactants (3a–e) showed good foaming stability, emulsion ability and wetting ability. The surfactants (3a–e) also have good antimicrobial activity against Staphylococcus aureus, Escherichia coli and Bacillus subtilis.     

Sensitivity of single wall carbon nanotubes to oxidative processing: structural modification, intercalation and functionalisation

The effect of oxidation on modification of single wall carbon nanotubes (SWCNTs) through successive purification steps has been studied. The efficient elimination of metal impurities has been followed by induced coupled plasma spectroscopy. Upon acid treatment, Raman spectroscopy clearly proofed that HNO₃ molecules were intercalated into the bundles of SWCNTs. At the same time, SWCNTs also have suffered a high degree of degradation and defects were introduced. The subsequent thermal processes led to the removal of further defect carbon materials and to the almost complete de-intercalation of the HNO₃ molecules. Changes in the structure of the SWCNT bundles have been observed by transmission electron microscopy. While bundles tend to separate upon acid treatment, after the complete purification process, the remaining SWCNTs tend to form thick bundles again. The existence of functional groups in the raw single wall carbon nanotubes material and their modification and almost complete removal after the final annealing step has been studied by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and temperature programmed desorption. Nitrogen adsorption isotherms analysed according to Brunauer-Emmet-Teller showed important changes in the pore volume and surface area through the purification steps.     

Synthesis,structural characterization and properties of novel functional poly(ether imide)/titania nanocomposite thin films

In this study, the synthesis, morphology, and thermal properties of new poly(ether imide)/titania nanohybrid films were investigated. The novel diamine containing functional nitrile groups was prepared in two steps by the nucleophilic substitution reaction and it was fully characterized by different techniques. Reaction of this diamine with pyromellitic dianhydride and 4-aminobenzoic acid gave poly(ether imide) with carboxylic acid end groups. This acid functionalized poly(ether imide) was condense with different amount of TiO₂ nanoparticles to provide organic-inorganic bonding, and the flexible films of these hybrid were prepared. The obtained materials were characterized by Fourier transform-infrared spectroscopy, thermogravimetry analysis (TGA), differential scanning calorimetry, X-ray powder diffraction, UV–Vis spectroscopy, field emission-scanning electron microscopy, and transmission electron microscopy (TEM) techniques. TEM of the nanohybrid films with 12% of TiO₂ contents confirms well dispersion of nanoparticles in the polymer matrix. TGA data indicated that the thermal behavior of the hybrid materials was increased with an increasing the content of TiO₂ nanoparticles. The tensile stress–strain of the hybrids was investigated and the resulting nanocomposites showed good mechanical properties. The permeability and selectivity of the PEI/TiO₂ membranes as a function of the titania weight percentage were study and the results indicated that the permeabilities of CO₂ and N₂ increase with increasing the titania content.     

Classifying rangeland vegetation type and coverage using a Fourier component based similarity measure

This paper defines a land cover classification technique based on the annual NDVI cycle. A similarity measure based directly on the components of the Discrete Fourier Transform is used to determine a pixels class membership. This Fourier component similarity measure produces an objective, computationally inexpensive and rapid method of classification that is able to classify rangeland vegetation by dominant shrub type, and which performs favorably compared to previously published classification techniques. By also defining a Fourier component based coverage measure this technique provides an estimate of vegetation coverage.     

A. I. Lobanov’s transformations

The concept of a Lobanov transformation is introduced. Its distinctive features and application to information coding are studied. It is shown that Lobanov transformations belong to the class of geometric transformation.Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 160–168, September–October 2004.