Process engineering of high-ethanol-tolerance yeast for the manufacture of ethanol

Applied Biochemistry and Biotechnology - Inhibitory effects of ethanol and glucose on a high-ethanol-tolerance yeast strain (fusion product ofSaccharomyces diastaticus andSaccharomyces uvarum)...     

单壁BN纳米管和碳纳米管物理吸附储氢性能的理论对比研究

采用巨正则蒙特卡罗方法(GCMC)研究了单壁氮化硼纳米管(SWBNNTs)和单壁碳纳米管(SWCNTs)的物理吸附储氢性能,主要对比研究了纳米管的管径、温度和手性对二者物理吸附储氢量的影响. 研究结果表明：在低温下,SWBNNTs的物理吸附储氢性能优于相应的SWCNTs;但是随着温度的升高,二者的物理吸附储氢性能差别越来越小,在常温下,SWBNNTs不具备有比SWCNTs更强的物理吸附储氢性能,而是和相同条件下的SWCNTs相差不大,只是在高压下的物理吸附储氢量稍稍大于SWCNTs,并给出了合理的理论解释 关键词： 巨正则蒙特卡罗方法(GCMC) 单壁氮化硼纳米管(SWBNNTs) 单壁碳纳米管(SWCNTs) 储氢     

固相萃取-气相色谱-质谱联用检测蔬菜中苄草隆残留及其断裂机理研究

建立了固相萃取-气相色谱-质谱法检测蔬菜中的苄草隆残留的分析方法。样品用乙腈提取,经液液分配,Carb/NH2双层柱净化后过滤膜上机。采用选择离子扫描方式,外标法定量。本方法简便、快速,通过优化前处理和上机条件,在最优条件下进行测试,苄草隆的定量检出限为0.008mg/kg,在加标水平0.01~0.5mg/kg范围内,回收率为98%~122%;相对标准偏差为6.9%~14.2%。对苄草隆的质谱检测断裂机理进行了研究。     

Determination of Benzocaine in Pharmaceutical Formulations by Indirect SERRS Assay Combined with Azo Coupling

Coupled with an azo coupling reaction, a simple, rapid, sensitive, and effective surface-enhanced resonance Raman scattering (SERRS) detection method for benzocaine was developed. In our study, benzocaine which is used clinically as a local anesthetic was derived with p-aminothiophenol into a corresponding azo product within 5 min, resulting in a strong SERRS response with the simple addition of Ag NPs excited with a 532 nm laser. The linear correlation between SERRS intensity of dominant bands and logarithm of benzocaine concentration was investigated for quantitative determination. The method reached a limit of detection (LOD) down to 0.139 and 0.0788 μg/mL calculated with two peak intensity ratios (I₁₅₆₈/I₂₂₆₀ and I₁₃₃₁/I₂₂₆₀), which is comparable to most studies reported previously, and meanwhile had superiority in simplicity and rapidness. The quantitative measurements for pharmaceutical preparations with benzocaine were conducted without complex extraction and enrichment processes. It was indicated that the SERRS assay combined with azo derivatization reaction has implications for practical applications in more complicated systems involving biological samples, in which appropriate and simplified pretreatments were conducted to remove interfering components.     

The impact of loyalty and promotion effects on retention rate

Researching customer retention rates is made difficult because of the lack of suitable systems with which to measure it. From a first-order Markov brand-switching model, serial equations are derived to estimate the retention rate using market share and loyalty. To explore the impact of loyalty and promotion programme on retention rate, data from five leading brands for three product categories were obtained to fit the developed model. Findings suggest that: (1) when the loyalty effect remains unchanged over a period of time, the greater the effect of a promotion programme, the greater the retention rate; (2) when the promotion effects among brands are similar, the retention rate varies depending on level of loyalty; and (3) when the proportion of loyal customers is high, the proportion of potential switchers affected by promotion programmes is low. In this case, the impact of a promotion programme on the retention rate is not significant. This model successfully demonstrates how the Markov brand-switching model can be employed to estimate a measure of retention rate from consumer panel data as well as to better understand how promotion affects loyalty, switching behaviour, and retention rate.     

The Growth of KLN Crystals

１ＩＮＴＲＯＤＵＣＴＩＯＮＣｒｙｓｔａｌｏｆＫ３Ｌｉ２＋ｘＮｂ５＋ｘＯ１５＋２ｘｉｓａｆｅｒｏｅｌｅｃｔｒｉｃｃｒｙｓｔａｌｂｅｌｏｎｇｉｎｇｔｏｔｅｔｒａｇｏｎａｌｓｙｓｔｅｍｗｉｔｈｔｈｅｓｔｒｕｃｔｕｒｅｏｆｔｈｅｍｉｎｅｒａｌｔｕｎｇｓｔｅｎ...     

忆阻器及其阻变机理研究进展

忆阻器是除电阻、电容、电感之外的第四种电路元件,在信息存储、逻辑运算和神经网络等研究领域具有重要的应用前景.本文综述了忆阻器以及忆阻器材料的研究进展,主要介绍了忆阻器的内涵与特征、阻变机理、材料类型以及应用前景,指出了目前忆阻器研究中需要关注的主要问题,并对以后的发展趋势进行了展望.     

AunXm(n+m=4,X=Cu，Al，Y)混合小团簇的结构和稳定性研究

采用基于密度泛函理论的B3LYP方法，优化了Au_nX_m(n+m=4,X=Cu，A l，Y)二元混合团簇的稳定结构.计算了稳定结构的平均结合能、电离势、电子亲和势、最高占据轨道能级和最低空轨道能级及二者间的能隙.结合Mulliken集居数分析研究了二元混合团簇稳定存在的规律，得出掺杂可以增强团簇稳定性的结论. 关键词： 混合团簇 结合能 能隙 分子轨道集居数