县域冬小麦生育期气候要素与产量的灰色关联度分析—以河南省为例

基于河南省及周边39个气象站1996-2015年逐日气象观测资料和冬小麦产量数据,采用灰色关联分析方法,分析生育期各气候要素与河南省县域冬小麦产量关联度的时空变化特征。结果表明:总体来看,各气候要素与河南省冬小麦产量的关联度中,气温的关联度最大,日照时数次之,降水量最小;关联度空间分布上呈现北部地区高于南部地区的格局,南北过渡性明显,尤其是南部信阳市的关联度较其它地区明显偏低。分时段来看,各气候要素与冬小麦产量关联度在1996-2010年有所下降,在2011-2015年突变上升,有明显的年际变化特征,尤其是位于西南部和南部地区的县域单元变化显著,而北部、东部和中部地区的县域单元变化较小。各气候要素与冬小麦产量关联度总体呈上升趋势,气候变化对冬小麦产量的影响逐渐显著,应积极采取策略应对气候变化的影响。     

光强和温度对球等鞭金藻(Isochrysis sphaerica)生长及其脂肪酸的影响

本研究测定了光照强度为16～58μmol/(m2·s)和15～30℃条件下球等鞭金藻(Isochrysis sphaerica)的生长曲线以及脂肪酸组成和含量.结果表明,在设置的光照强度范围内,光照强度越强,微藻的生长速度越快.光强对各种脂肪酸的含量影响有差异,过低和过高都不利于藻体内多不饱和脂肪酸(Polyunsaturated Fatty Acids,PUFAs)的积累.当光强为24μmol/( m2.s)时二十二碳六烯酸(Docosahexaenoic Acid,DHA,C22:6 n-3)的积累量最高,占总脂肪酸的11.77%.球等鞭金藻的最适生长温度在20—25℃之间,低温条件有利于不饱和脂肪酸的积累.光强20μmol/( m2.s)、温度20℃条件下总不饱和脂肪酸(Total Unsaturated Fatty Acids,TUFAs)含量最高,达64.99%;同样的光强,温度15℃条件下DHA占总脂肪酸的12.19%.可见适宜的光强和温度是利用球等鞭金藻收获PUFAs的关键.     

西北太平洋SST暖水区·ITCZ对东北冷涡及副热带高压的影响

利用1958～1997年NCAR/NCEP再分析月平均500hPa位势高度格点资料,分析了东北冷涡与西太平洋副热带高压的关系,研究了海表温度（SST）和射出长波辐射（OLR）对东北冷涡及副热带高压的影响。结果表明,在夏季,东北冷涡与副热带高压是正相关关系,GMS-SST=28℃阈值特征线与东北冷涡高度指数、副热带高压高度指数都是反位相关系,随着GMS-SST=28℃阈值特征线的逐渐北移,副热带高压减弱,东北冷涡增多、加强。     

Optimization of switchgrass and extruder parameters for enzymatic hydrolysis using response surface methodology

Switchgrass is an important biomass that can be hydrolyzed to yield fermentable sugars through pretreatment, which is the primary and expensive step in conversion of biomass to bio-ethanol. Most of the pretreatment operates in batch mode, which is energy intensive, requires high capital, results in decomposition of hemicellulose, and formation of inhibitors. Considering these shortcomings, a novel biomass pretreatment method using a high shear bioreactor could be a viable continuous one. The current study was undertaken to determine the effect of biomass parameters such as moisture content (10, 20, 30, 40, and 50% wb) and particle size (2, 4, 6, 8, and 10 mm) over a range of barrel temperature and screw speed (45-225 °C and 20-200 rpm). Statistical analyses revealed that among the independent variables considered temperature, screw speed, and moisture content had significant effect on sugar recoveries. Proposed quadratic model to predict glucose, xylose, and combined sugar recoveries from switchgrass had a high F and R² values indicating that the model has the ability to represent the relationship among the independent variables studied. The optimum pretreatment condition of barrel temperature 176 °C, screw speed 155 rpm, moisture content 20% wb, and particle size 8 mm resulted in maximum glucose, xylose, and combined sugar recoveries of 41.4, 62.2 and 47.4%, respectively. The optimum pretreated switchgrass had 50% higher surface area than that of the control.     

Effect of temperature and durations of heating on coir fibers

Biocomposites derived from polymeric resin and lignocellulosic fibers may be processed at temperatures ranging from 100 °C to 230 °C for durations of up to 30 min. These processing parameters normally lead to the degradation of the fiber's mechanical properties such as Young's modulus (E), ultimate tensile strength (UTS) and percentage elongation at break (%EB). In this study, the effect of processing temperature and duration of heating on the mechanical properties of coir fibers were examined by heating the fibers in an oven at 150 °C and 200 °C for 10, 20 and 30 min to simulate processing conditions. Degradation of mechanical properties was evaluated based on the tensile properties. It was observed that the UTS and %EB of heat treated fibers decreased by 1.17-44.00% and 15.28-81.93%, respectively, compared to untreated fibers. However, the stiffness or E of the fibers increased by 6.3-25.0%. Infra red spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to elucidate further the influence of chemical, thermal and microstructural degradation on the resulting tensile properties of the fibers. The main chemical changes observed at 2922, 2851, 1733, 1651, 1460, 1421 and1370 cm⁻¹ absorption bands were attributed to oxidation, dehydration and depolymerization as well as volatization of the fiber components. These phenomena were also attributed to in the TGA, and in addition the TGA showed increased thermal stability of the heat treated coir fibers with reference to the untreated counterparts which was most probably due to increased recrystallization and cross linking. The microstructural features including microcracks, micropores, collapsed microfibrils and sort of cooled molten liquid observed on the surface of heat treated coir fibers from the scanning electron microscope (SEM) could not directly be linked to the effect of temperature and durations of heating although such features may have largely account for the lower tensile properties of heat treated coir fibers with reference to untreated ones.     

勐海县水稻粘虫的发生及与气候的关系

通过分析1982～2007年勐海县气候因子及粘虫数量变化,探讨了两者的关系,结果表明：粘虫的发生与该县的气候条件有一定的关系,其中温度与粘虫数量间存在极显著相关关系,温度影响着粘虫发生的数量,回归关系为y=2.691x-57.123（R2=0.110）;相对湿度与粘虫数量间没有显著性相关关系;降雨量与粘虫数量大发生有明显关系。     

谷物烘干机温度控制系统的设计

介绍了燃油循环式谷物烘干机的工艺流程,提出了谷物烘干自动控制方案,实现了用PLC对谷物烘干的自动控制。     

利用RegCM3模式模拟新疆区域气候

为了检验高分辨率区域气候模式RegCM3对新疆气候的模拟能力,对2005年夏季气候进行了模拟试验,针对模拟的温度场和降水场作了具体分析,并利用新疆境内102个气象站点的逐日资料对温度场和降水场进行了检验分析。温度场的模拟结果表明,模式能较好地反映新疆的温度场空间分布特征,但在数值上出现明显的＂冷偏差＂,整体偏低4～7℃;模式较好地模拟了新疆的夏季降水特征：降水高值区位于天山山区。模式对平原地区的降水模拟较接近实测值,但对山区的模拟效果较差。     

内蒙古东部近40年气温降水变化特征分析

利用内蒙古东部四盟市48个地面气象观测站自1951～2005年的地面气象观测资料,采用趋势分析方法分析了内蒙古东部地区降水量、降水日数、极端降水事件、气温、极端气温的变化趋势及空间分布特征。结果表明,40多年来内蒙古东部地区气温升高,且极端最低温度升高的程度大于极端最高温度升高的程度;呼伦贝尔市东部和赤峰市西南部降水增加较明显,通辽市降水减少最明显。大部分地区降水日数呈减少的趋势,仅呼伦贝尔市的西南部、东部和北部的降水日数呈增加的趋势,大于25mm的极端降水事件呈增加的趋势。     

淄博市近40年降水及气温时空特征分析

利用淄博市1966～2005年的历年逐月降水和气温资料,应用趋势分析等气候诊断方法和墨西哥帽小波变换分析方法,对淄博市五区三县的降水及气温时空变化特征进行了分析。结果表明,淄博市的降水和气温随着年代际发生变化,降水量以平均每年1.5mm的速度缓慢增加,且存在32年、25～29年、10～23年和准5年的多尺度振荡周期,明显的突变点在1977和1995年,1977年之前和1995年之后降水偏多,1977～1995年降水偏少;年平均气温以0.48℃/10a的速度上升,且存在21～32年、17～21年、9～13年和2～3年的多尺度振荡周期,明显的突变点在1991年,之前,气温偏冷,之后气温偏暖。淄博市的降水和气温在地域分布上存在较大差异,降水自南向北呈递减趋势,气温则呈南、北低,中部高,可分为南部型、中部型、北部型3个型。