紫花苜蓿高频体细胞胚与次生胚再生体系的建立

通过系统地对紫花苜蓿体细胞胚发生以及次生胚发生途径中若干影响因子的比较研究,建立了紫花苜蓿高频体细胞胚和次生胚再生体系.结果表明,体细胞胚再生体系及次生胚再生体系均具有严格的基因型依赖性,不同的品种间以及同一品种内的不同株系间再生频率存在较大差别;MSO培养基可作为胚状体成苗培养基,但次生胚在MSO培养基中成苗率较低而再次形成新的胚状体;改良无激素SH培养基可有效终止次生胚的发生,并诱导次生胚成苗.此外,从6个紫花苜蓿品种中筛选到3个具有较强胚状体再生能力的品种,6个高胚状体发生能力的株系,2个具有较强的次生胚发生能力的株系,为进一步的遗传转化奠定了基础.     

Two-dimensional simulation of Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect

Poiseuille-Rayleigh-Bénard flows in binary fluids with Soret effect are directly simulated by a mixed finite element method. A temperature perturbation is used as an initial disturbed source for the basic parallel flows. The whole spatio-temporal evolution of the binary fluid flows is exhibited: initially only the disturbed mode with the wavenumber k=π is amplified while others are damped, and continuously the amplified mode grows further and the nonlinear effect becomes important; after a nonlinear evolution transition the flow system evolves finally into a periodic right traveling wave.     

Protective effect of sodium butyrate on the cell culture model of Huntington disease

This study aimed to develop a cell culture model of Huntington disease and observe the effect of sodium butyrate on this cell culture model. Exon 1 of both a wild type and a mutant IT15 gene from the genomic DNA of a healthy adult and a patient with Huntington disease was amplified and cloned into the eukaryotic expression vector pEGFP-C1. Human neuroblastoma SH-SY5Y cells were transiently transfected with these recombinant plasmids in the absence and presence of sodium butyrate (0.1, 0.2, 0.5, 1.0 mmol/L). The MTT assay was used to measure cell viability. The results indicated that the N-terminal fragment of mutant huntingtin formed perinuclear and intranuclear aggregates and caused a decrease of SH-SY5Y cell viability. Sodium butyrate inhibited the decrease of SH-SY5Y cell viability caused by the N-terminal fragment of mutant huntingtin. This suggests that sodium butyrate has a protective effect on this cell culture model of Huntington disease.     

Effects of historical land cover changes on climate

In order to explore the influence of anthropogenic land use on the climate system during the last mil- lennium, a set of experiments is performed with an Earth system model of intermediate complexity—— the McGill Paleoclimate Model (MPM-2). The present paper mainly focuses on biogeophysical effects of historical land cover changes. A dynamic scenario of deforestation is described based on changes in cropland fraction (RF99). The model simulates a decrease in global mean annual temperature in the range of 0.09-0.16℃, especially 0.14-0.22℃ in Northern Hemisphere during the last 300 years. The responses of climate system to GHGs concentration changes are also calculated for comparisons. Now, afforestation is becoming an important choice for the enhancement of terrestrial carbon sequestration and adjustment of regional climate. The results indicate that biogeophysical effects of land cover changes cannot be neglected in the assessments of climate change.     

均质条件对明胶乳液膜物理性能及控释性的影响

针对蛋白膜材料机械性能和水汽阻隔性能较差的问题,采用微射流乳化的方法制备了新型橄榄油/明胶乳液膜材料,分析了均质条件对成膜乳液粒径分布和乳液膜物理性能的影响,并探讨了膜材料中油滴分布与膜材料的机械性能和水汽阻隔性之间的关联性,以及膜材料对溶菌酶的控释性.结果表明:高速分散处理的成膜乳液的油滴粒径较大且分布不均,成膜过程中部分油相富集在膜表面形成类似双层结构,膜材料机械性能较差;而经过微射流处理可以获得纳米尺度的粒子集中分布的成膜乳液,膜材料中油相均匀分散,具有良好的的抗拉强度;与对照膜相比,两种处理方法制备的乳液膜均有着较强的水汽阻隔性,但对于不同均质处理呈现不同的机制;利用微射流处理制备的膜材料具有良好的机械性能和水汽阻隔性,并对溶菌酶良好的控释性.     

基于转矩控制的上坡辅助电控系统

针对车辆坡道起步时加速踏板和制动踏板协同操纵难度大、易引发溜坡事故等问题,提出一种基于电机转矩控制的电动汽车上坡辅助控制方法.建立了车辆坡道起步动力学模型,构建了具备"前馈+反馈"结构的预加载上坡辅助控制算法以保证控制实时性,通过时域分析法揭示了控制参数对系统稳定性、稳态误差和动态性能的影响机理.开发了面向量产纯电动乘用车平台的实车控制系统,分析了整车CAN网络通信架构.综合考虑溜坡距离和乘坐舒适性,通过道路试验确定了最优的控制参数组合,并将试验结果与现有的纯PI调节和负载观测器调节进行了对比分析.结果 表明,预加载上坡辅助控制算法相比于纯PI调节,可以减少11 cm的溜车距离,将溜车距离控制在3 cm以内,有效解决了坡道起步的溜车问题.     

海南岛棕果蝠不同季节血象的观察

为了测定海南岛棕果蝠(Rousettus leschenaulti)不同季节血液生理指标的参考值,对不同季节的棕果蝠进行脚趾静脉采血,做血液涂片观察血细胞形态,并使用MiVNT图象分析软件对其进行分析;同时做血常规分析,对血细胞数量、形态以及血红蛋白含量等进行了测定.结果表明:其红细胞形态与其他哺乳动物相似,呈双凹圆盘形,无细胞核;六种白细胞均能清晰的观察到;血细胞的各种生理指标具有季节性变化(ANOVA,P＜0.05),在冬季红细胞数量(12.8±0.74)×1012/L、白细胞数量(11.7±6.82)×109/L,血红蛋白含量(182.0±15.47)g/L均较其他季节高;随着气温的下降,红细胞平均体积(44.73±1.52)fL、红细胞压积(0.58±0.05)L/L、红细胞体积分布宽度0.21±0.01都变大.结论:棕果蝠的血液生理指标受多种因素影响,但是这种变化与其活动节律、繁殖行为等相适应.     

不同粒度肥煤的膨胀性研究

对不同粒级淮北宿州肥煤的奥亚膨胀度、黏结指数、最大胶质层厚度、有机显微组分、挥发分以及镜质组氧元素含量进行分析。结果表明,不同粒级肥煤的黏结指数G值和最大胶质层厚度Y值无明显差异,且奥亚膨胀度b值和膨胀温度区间的变化趋势基本一致;0.5～2mm粒级肥煤的膨胀性能较优,粒度大于2mm或小于0.5mm肥煤的最大膨胀度b值和膨胀温度区间相对较小,其膨胀性能明显劣化。讨论了采用膨胀性指标表征肥煤工艺性质的优越性,并从活惰比、镜质组氧元素含量和活性成分比表面积对不同粒级肥煤膨胀性差异进行了分析。     

基于Hu不变矩扩展的交通标志识别

交通标志的识别是智能交通系统(ITS)的组成部分之一，具有十分重要的意义，对Hu提出的区域不变矩和Chen提出的区域不变矩快速算法进行了扩展，得到一组新的描述形状特征的参数，这些参数具有平移、缩放和旋转不变性，并且具有较低的计算复杂性，具有Hu和Chen方法的综合优点．     

风电机组振动故障的检测方法

论述了风电机组振动故障检测的重要性及常用的振动故障的检测方法;归纳比较了小波变换法、神经网络法、神经网络与模糊理论结合法及人工免疫法的性能与优缺点;分析了我国在风电机组故障检测预警系统方面的现状与发展趋势;指出目前小波变换故障诊断法在我国已趋成熟,而人工智能检测法的应用才刚刚起步.