苹果渣浸液培养嗜酸乳杆菌条件的研究

以苹果鲜渣为原料,利用嗜酸乳杆菌发酵其浸提液,以活菌数为主要指标,通过单因素试验和响应面分析(RSM)对发酵条件进行优化,确定嗜酸乳杆菌发酵苹果渣浸液的最佳工艺条件为:料水比为1:8～1:10,100℃浸提50～60 min,过滤,添加1.56%酵母粉,1.54%乳清粉,发酵28.14 h,活菌数可达到5.24×109 cfu/ml。     

响应面法优化黑盖木层孔菌菌丝体液体发酵培养基研究

应用Plackett-Burman设计法对影响液体发酵黑盖木层孔菌菌丝体产量的培养基组分进行筛选,确定影响菌丝体产量的关键因素为玉米粉、麸皮和VB1。在此基础上,采用最陡爬坡试验结合Box-Behnken响应面法优化黑盖木层孔菌液体发酵培养基。结果表明:当培养基组分中玉米粉为65 g/L、麸皮为49.31 g/L、VB1为214.61μg/L时,菌丝体产量预测值为10.75 g/L,最佳条件下菌丝体产量可达11.16 g/L,预测值与验证值吻合得较好。     

响应面法优化枳椇果汁的制备工艺

以枳犋果柄为原料,通过单因素试验和响应面法,优化工艺条件,探讨枳椇果汁的生产工艺.结果表明:枳犋果汁提取的最佳工艺参数为水浴温度50℃、液固比10∶1、pH值2.5、浸提时间4h、果胶酶0.045 g/10g干果.以此工艺制备的枳椇果汁具有枳犋特有的果香,风味独特,味道酸甜可口.     

Effects of temperature,water regime and irrigation system on the release of ascospores of Mycosphaerella nawae,causal agent of circular leaf spot of persimmon

Experiments were conducted under controlled conditions to quantify the effects of temperature, water regime and irrigation system on the release of Mycosphaerella nawae ascospores from leaf litter in Spanish persimmon orchards. The effect of temperature on ascospore release was best described by a Gompertz model. The end of the lag phase of ascospore release occurred at 9·75°C, and the end of the exponential phase at 15·75°C. Few ascospores were discharged from dry leaves wetted with 0·1 or 0·5 mm water, but significant amounts were recovered with 1–50 mm water. About half of the total ascospores were released after three wetting and drying cycles, but 32 cycles were necessary for a complete discharge. No significant difference in ascospore release was detected when the leaf litter was wetted by flood and drip irrigation. However, considering the proportion of soil area wetted in both systems, inoculum release was significantly reduced by drip irrigation. The potential of drip irrigation as a cultural control measure should be investigated.     

Assessment of wood surface roughness: comparison of tactile roughness and three-dimensional parameters derived using a robust Gaussian regression filter

Japanese oak and Japanese beech were sanded by hand with abrasive papers of varying grit number. Two three-dimensional parameters selected to characterize their surface roughness – one parameter for the distribution of roughness-profile peaks and the other for the relative area of the roughness-profile peaks above the threshold height – were compared against tactile roughness. The parameters were obtained from roughness profiles as determined by a robust Gaussian regression filter (RGRF) using seven cutoffs. The RGRF filtering process was adjusted specifically for the evaluation of wood surface roughness. Except for a cutoff wavelength of 0.25mm, the RGRF lent itself well to the determination of roughness profiles. No distortion of roughness profiles occurred around deep valleys, and there was a good correlation between the parameters and tactile roughness.Part of this study was presented at the 2002 Kansai Branch Office lecture meeting of the Japan Society for Precision Engineering, Kyotanabe, August 2002     

民勤荒漠区无霜期及春季低温变化特征分析

以甘肃民勤治沙综合试验站数十年气象定点观测资料为基础,统计、分析了民勤荒漠区无霜期、春季低温、冻土层的变化特征。结果显示:该地区平均终霜期为5月10日,初霜期为9月28日,50 a来终霜期有逐渐提前、初霜期有逐渐推后的趋势,但不同年份变异幅度增大;3-5月份地表平均最低温度、气温逐渐上升,≤0℃出现比率下降,但4月下旬至5月上旬大强度的降温天气时有发生;3月份冻土层的变化与气温变化趋势相近。30 a以来地表平均日最低温度和气温亦有所提高。     

鸟类羽被防水性能的形态学基础

提出用水-羽毛接触点密度(Dp)的指标来描述鸟类廓羽表面的防水性能。29种鸟类胸部廓羽的检测表明,除了极少数物种以外,陆禽的Dp较小,涉禽和潜水鸟类的Dp居中,而游禽的Dp较大。这表明鸟类通过羽毛微观结构的变化来使羽毛具有相应水平的防水性能。因此,Dp是一个连接羽毛结构和功能的指标,对鸟类的适应性进化的研究具有重要意义。图3表1参9。     

迎面火与主地表火相互作用的实验研究

为了研究地表火卷吸作用的范围和迎面火与主火相互作用的机理 ,在大空间室内实验室进行了实验研究 .在该实验室实验可以避免环境风和环境温度变化的影响 .研究结果表明 :(1)在火头前方有明显的逆风区存在 .在逆风区下部的逆风风速要比上部的大 ,而且当高度达到某一数值时 ,逆风就不明显了 ;(2 )迎面火与主火之间即使相距较远也存在相互作用 .当它们相互接近到一定程度时 ,彼此相互吸引 .这使得火的蔓延速度显著升高 .对于火线火强度为 16 0kW·m-1地表火来说 ,蔓延速度增加2 7% .