关于溶液中酸碱组分的分布的再讨论

本文针对学生关于溶液中酸域组分的分布系数的计算所出现的错误，对溶液中酸碱组分的分布进行再讨论，提出对一元碱及多元碱酸效应分布系数的推导和应用，并总结出其规律．

Experimental study on the durability of BFRP bars embedded in concrete

This paper presents an experimental study on the alkali-resistant properties of basalt fiber reinforced polymers （BFRP） bars under a typical concrete environment. BFRP bars were embedded in concrete and exposed to different aggressive environments, including tap water, saline solution and ambient temperature environments, to study the effects of the type of solution and relative humidity （RH） on the durability of BFRP. Meanwhile, BFRP bars were directly immersed in an alkaline solution for comparison. The acceleration factor describing the relationship between the alkaline solution immersion and the moisture-saturated concrete was also obtained. Aging was accelerated with a temperature of 60 ℃. The results show that the chloridion in the saline solution does not have any harmful effects on the degradation of the concrete-encased BFRP bars. Contact with an alkaline （high pH） concrete pore-water solution is the primary reason for the degradation of the BFRP bars. The degradation rate of concrete-encased BFRP bars is accelerated when a high temperature and a high humidity are present simultaneously. The degradation rate of the BFRP bars is relatively quick at the initial stage and slows down with exposure time. Results show that the degradation of 2.18 years in moisture-saturated concrete at 60 ℃corresponds to that of one year when directly immersed in an alkaline solution （other conditions remaining the same） for the BFRP bars analyzed.

配平氧化还原反应方程式的一种常用方法

对于中学生来说,要配平氧化数没有改变的酸碱反应、沉淀反应、一般络合反应并非难事。但对于众多的比较复杂的氧化——还原反应方程式的配平则感到困难。本文将就怎样配平这类方程式介绍一种简便而有效的配平方法供同行指正。

Computational identification and characterization of microRNAs and their targets in Penaeus monodon

Study on shrimp miRNAs was limited and just 7 mature miRNA sequences of Marsupenaeus japonicus are deposited in mir Base database. In this study, miRNAs and their target gene candidates were computationally identified from shrimp Penaeu s monodon and then experimentally validated. Using 39 908 expressed sequence tags(ESTs) and 21 124 genome survey sequences(GSSs) of P. monodon(pmo) as reference dataset, a comprehensive approach based on inter-species homolog search was employed to investigate the candidate miRNAs(i.e. pmo-miRNA). A total of eight miRNAs belonging to 7 families were computationally identified and five out of them were subsequently validated by PCR and sequencing. Of these, pmo-miR-4961a, pmo-miR-4961b, pmo-miR-4979 and pmo-miR-3819 were first identified from shrimps. Both the mature pmo-miRNAs and the corresponding precursors were conserved among different species. Based on perfect or near-perfect match to the target region, the target gene candidates of pmomiRNAs were predicted from 10 331 mRNA sequences of P. monodon. A total of 20 genes were predicted as the targets of pmo-miR-4961a, pmo-miR-4961b, pmo-miR-4979 and pmo-miR-6492. Experimental validation by dual luciferase reporter assay confi rmed the targeting between 3 pmo-miRNAs and one or two of their target genes, especially the pmo-miR-4979 which could significantly down-regulate the expression of target gene(JR226772). This study updates the miRNAs and their targets in P. monodon and lays a solid foundation for future RNAi study.

A New Method for Characterizing Single Parametric Model Potential

A novel approach of characterizing single parametric model potential is proposed by equating total pair wise force to zero. Our well-established single parametric model potential is characterized using the proposed idea and compared the obtained parameter with parameters computed by previously used approaches. Thus characterized pseudopotential is then tested to compute total energy of alkali metals. The results establish the reliability of proposed idea of making total pair wise force to zero in determining the parameter of the pseudopotential.

破碎解理方式对高岭石颗粒电动特性的影响

为了掌握不同粒度高岭石颗粒的电动特性,利用ZetaProbe分析仪测定了其在溶液中的表面ζ电位,分析了不同解理方式对颗粒各面面积的影响,研究了破碎解理方式对高岭石颗粒在溶液中电动特性的影响规律.结果表明:D_(50)分别为0.30,4.65和7.95 mm 3种高岭石颗粒的等电点(IEP)随粒度的增加呈先降后增的趋势;3.00<pH<7.40时,高岭石颗粒表面的负ζ电位与粒度正相关,而pH≥7.40时,随粒度的增加呈先降后增的趋势;T-O解理会使高岭石颗粒酸碱响应系数α值减小,E-E解理则会增大颗粒的α值;大粒度高岭石破碎时T-O解理较多,随颗粒粒度的减小,E-E解理逐渐增多是不同粒度高岭石颗粒群电动特性的主要成因.

High-Order Dispersion Coefficients for Alkali-metal Atoms

High-order dispersion coefficients C9, C11, C12, and C13 for the ground-state alkali-metals were calculated by combining the 1-dependent model potential of alkali-metal atoms and linear variation method based on B-spline basis functions. The results were compared.

Separation characteristics of boron isotopes in continuous annular chromatography

A well designed continuous annular chromatograph （CAC） column was set to stndy the enrichment of Boron isotopes. The column is 820 mm high and consists of a rotational annulus with an outer diameter of 246 mm and a width of 15 mm. The weak basic resin （Diaion WA21J）, the boric acid and water were used as the absorbent, the feed and the eluent respectively. The effects of CAC rotating speed, concentration of boric acid and flow ratio of eluent to feed on the enrichment of 10B were investigated. The concentration of boron isotope was determined by a Thermal Elemental X7 ICP-MS （Thermo Electron Co., USA）. It is shown from the experimental results that 10B and 11B can be separated effectively by this CAC column. By fitting the experimental elution profiles based on reliable mathematic models and software the mass transfer coefficient k and adsorp- tion equilibrium constant K values of 10B and 11B in CAC column were estimated. It is clear from this study that the CAC has practical continuous operational capabilities in comparison with fixed batch chromatography and is an effective technology for seoarating boron isotones.