学习策略培训对高职高专学生听力的影响

以实验方法探究学习策略培训(SBI)对高职高专学生听力的影响。结果发现:策略培训对高职高专学生的听力有积极作用;这种作用在低水平学习者身上体现得更明显;高职高专学生使用所有学习策略的频率都很低。因此,在教学中,高职高专英语教师应该在听力教学中引入直接的、明确的策略培训,并且结合应用于日常教学中。在策略培训中,不要忽略低水平学习者,他们是最需要策略培训并且会从中获益最多的群体。     

正交试验法筛选藏药红毛五加多糖的提取分离工艺

目的: 研究藏药红毛五加多糖的提取分离的最佳工艺条件.方法: 采用正交设计法筛选.结果: 藏药红毛五加多糖的最佳提取分离工艺为: 采用加热回流法,石油醚(30～60 ℃)回流6 h,95%乙醇回流4 h,滤渣加14、 12倍量的水,提取2 h,提取2次,提取液浓缩到50 mL,加醇使醇浓度达到80%,静置16 h,减压过滤,滤渣真空干燥,得红毛五加多糖粗品.结论: 本实验为藏药红毛五加多糖的提取分离的条件提供了参考,为藏药红毛五加的进一步开发研究提供依据.     

芳香型二丁基锡双羧酸酯的合成、表征及抗癌活性研究

用二正丁基氧化锡和取代芳香单羧酸以1∶2摩尔比反应,合成了10个芳香型二正丁基锡双羧酸酯n-Bu2Sn(OOCAr)2(3a~3j).利用1H NMR,119Sn NMR和IR等对这些化合物进行了表征.并用X-射线单晶衍射测定了其中化合物3b和3e的晶体结构.3b和3e晶体中锡原子配位数均为6,形成了严重扭的曲八面体几何构型.3b和3e均存在分子内及分子间氢键作用,3b中氢键作用较弱,在生物体系中比3e更易释放出游离态R2Sn2 ,易与癌细胞的DNA结合,具有更好的抗癌生物活性.     

Improved Prediction and Reduction of Sampling Density for Soil Salinity by Different Geostatistical Methods

The spatial estimation for soil properties was improved and sampling intensities also decreased in terms of incorporated auxiliary data. In this study, kriging and two interpolation methods were proven well to estimate auxiliary variables： cokriging and regression-kriging, and using the salinity data from the first two stages as auxiliary variables, the methods both improved the interpolation of soil salinity in coastal saline land. The prediction accuracy of the three methods was observed under different sampling density of the target variable by comparison with another group of 80 validation sample points, from which the root-mean-square error （RMSE） and correlation coefficient （r） between the predicted and measured values were calculated. The results showed, with the help of auxiliary data, whatever the sample size of the target variable may be, cokriging and regression-kriging performed better than ordinary kriging. Moreover, regression-kriging produced on average more accurate predictions than cokriging. Compared with the kriging results, cokriging improved the estimations by reducing RMSE from 23.3 to 29% and increasing r from 16.6 to 25.5%, regression-kriging improved the estimations by reducing RMSE from 25 to 41.5% and increasing r from 16.8 to 27.2%. Therefore, regression-kriging shows promise for improved prediction for soil salinity and reduction of soil sampling intensity considerably while maintaining high prediction accuracy. Moreover, in regression-kriging, the regression model can have any form, such as generalized linear models, non-linear models or tree-based models, which provide a possibility to include more ancillary variables.     

Comparison of Near Infrared Spectroscopy Models for Determining Protein and Amylose Contents Between Calibration Samples of Recombinant Inbred Lines and Conventional Varieties of Rice

The near infrared spectra of 178 recombinant inbred lines （RILs） from the cross of Ⅱ-32B/Yuezaoxian 6 （YZX6） and 511 varieties in rice were acquired. A total of 80 RILs and 96 cultivars were selected as modeling samples by comparing the spectra similarity primarily. Three partial least square （PLS） regression models were developed, based on the RILs （RIL-model）, the varieties （Var-model） and their mixture （Mix-model）, for protein content （PC） and amylose content （AC）, respectively. Cross validation and outer prediction showed that the models were largely influenced by the range and distribution of modeling samples. The regression model of PC based on the cultivars and the model of AC based on RILs had higher coefficient of determination （r^2 ≥ 0.9） and lower root mean square error of cross validation （RMSECVs）. The disadvantages of RIL samples for PC model and variety samples for AC model were probably caused by the narrow range of variance. Aberrant predictions were obtained for outer sample with PC or AC outside the range or within the distribution gap of modeling samples. The Mix-models gave more reliable prediction as the distribution of RIL and variety modeling samples were complementary to each other.     

3-羟基,12-羧基印楝素的制备、结构鉴定及生物活性测定

对印楝素进行水解反应,得到3-羟基,12-羧基印楝素,以浸叶喂食法研究了3-羟基,12-羧基印楝素对小菜蛾Plutella xylostella、斜纹夜蛾Spodoptera litura和棉铃虫Heliothis armigera的生物活性.结果表明,在室温敞开体系贮存15 d后,印楝素、印楝素干粉和印楝种子甲醇粗提物溶液中印楝素大部分降解,但溶液仍对斜纹夜蛾幼虫具有良好的毒杀活性.处理后24 和48 h,3-羟基, 12-羧基印楝素对斜纹夜蛾3龄幼虫的AFC50值分别为37.19 和 50.18 μg/mL.在3 μg/mL的剂量下处理后24 h,3-羟基,12-羧基印楝素对小菜蛾3龄幼虫的拒食率为 46.69 %;在5 μg/mL的剂量下处理后24 h,对棉铃虫3龄幼虫的拒食率为75.65 %;在3 μg/mL的剂量下处理后72 h,小菜蛾3龄幼虫的死亡率为61.28 %;在5 μg/mL的剂量下处理后72 h,棉铃虫3龄幼虫的死亡率为47.65%;在 2.0 μg/mL 的剂量下处理后72 h,棉铃虫3龄幼虫的体质量下降率为48.93 %;在1.0 μg/mL的剂量下处理后 72 h,斜纹夜蛾3龄幼虫的体质量下降率为41.18 %.     

退耕还林对农户经济影响的分析——以陕西省吴起县为例

以陕西省吴起县为例,通过对1 619户农户的全面调查,了解农民对退耕还林政策的态度,系统分析了退耕还林工程的实施对当地农民的经济收入、行为方式、种植业、畜牧养殖业以及产业结构的影响,结果表明:退耕还林不仅使当地农民受惠,而且促进了该县农村经济结构的调整和区域经济的发展.     

猪源支气管败血波氏杆菌的分离鉴定及生物学特性研究

 【目的】探讨2003～2006年间支气管败血波氏杆菌（Bordetella bronchiseptica,Bb）在中国湖北等十余省市猪群中的流行病学分布和协同感染特性并对部分菌株进行生物学特性研究。【方法】采用病原菌的形态学观察、生化鉴定和PCR鉴定,从2 057份有肺炎或萎缩性鼻炎症状猪的肺脏等病料组织中分离出190株Bb和不同数量的其它共感染菌。经生化鉴定,药敏试验、血凝试验及动物试验等方法进行检测和分析。【结果】在中国湖北等十余省市的猪群中,不同省份Bb的总分离率介于7.3%～14.1%之间;不同年份Bb的总分离率介于7.3%～11.8%之间;2003～2006年间的Bb总分离率为9.2%;Bb的分离率与猪日龄有一定的关系。Bb最常见的共感染菌依次是链球菌（55.9%）、副猪嗜血杆菌（50.0%）、大肠杆菌（43.1%）、巴氏杆菌（25.5%）、绿脓杆菌（17.6%）和沙门氏菌（11.8%）。在43份有典型萎缩性鼻炎症状猪的病料中,分离出22株Bb、7株产毒素巴氏杆菌和6株绿脓杆菌;在分离出产毒素巴氏杆菌的7份病料中均同时分离出了Bb,而其中6份又同时分离出了绿脓杆菌。对2003年分离的31株Bb进行药敏试验、红细胞凝集试验和乳鼠皮肤坏死试验。结果表明：各菌株对15种药物的耐药谱不同,但对卡那霉素、庆大霉素、多粘菌素B、环丙沙星和舒普深高度敏感;各菌株均可凝集猪和羊的红细胞且能不同程度导致乳鼠皮肤坏死。【结论】在中国湖北等十余省市的猪群中,Bb与其它病原菌的共感染情况非常严重,且在萎缩性鼻炎的病猪中检出率最高。     

基于车速分段的多模型切换在车道保持系统中的应用

针对目前车道保持系统中车速变化较大时被控车辆道路跟随性能较差的问题,采用基于车速分段的多模型切换方法,结合最优控制策略设计车辆横向控制算法建立车道保持系统控制策略。计算仿真及实车试验结果表明：所建立的基于车速分段的多模型切换算法能够在车速变化范围较大时有效降低被控车辆的车-路偏移量,一般工况下,能够使车-路偏移量控制在10 cm以下;车-路偏差在车道保持试验过程中平缓、稳定调整,满足车道保持系统控制精度的要求;与单模型设计控制算法的车道保持系统相比,被控车辆对车道中心线的跟随性能得到有效提高。     

不同母质条件下海南省胶园土壤肥力特性研究

[目的]为胶园土壤肥力的管理提供依据。[方法]对海南省胶园酸性火成岩、基性火成岩、酸性变质岩、沉积岩、冲积物、海积物等不同母质发育下的土壤有机质和氮磷钾养分含量进行分析,研究胶园土壤肥力指标与其母质之间的关系。[结果]胶园不同土层土壤有机质、全氮、全磷含量均为在玄武岩中最高,全钾、缓效钾含量在花岗岩中最高。胶园0~20 cm土壤速效氮含量在页岩中最高,21~40、41~60 cm土壤速效氮含量在玄武岩中最高。[结论]胶园土壤有机质和氮磷钾养分含量在一些母质上对母岩特性有继承性,但生物气候及耕作与施肥等因素已经完全弱化了因母岩成分不同而造成的土壤有机质及氮磷钾养分含量的差异。