季也蒙毕赤酵母MCJ-1培养条件优化及其冻干菌粉的制备

康普茶是一种酸甜味发酵饮料,由酵母、糖和发酵茶制成。该研究以从康普茶混菌体系中筛选获得的季也蒙毕赤酵母(Pichia guilliermondii)MCJ-1为研究对象,采用单因素试验及响应面法优化菌株MCJ-1的培养条件,并制备其冻干菌粉。结果表明,菌株MCJ-1的最佳培养条件为:蔗糖25.00 g/L,氯化铵7.7 g/L,蛋白胨10.00 g/L,酵母浸粉5.00 g/L,培养温度30℃,初始pH值为6,转速200 r/min。在此优化培养条件下,菌体干质量为(5.06±0.22)mg/mL,比优化前提高了64.82%。菌粉制备中菌泥与保护剂的比例为1:1,保护剂甘油添加量为4.0%,可以获得存活率达(80.83±5.36)%的冻干菌粉。

Topographical Parameter Characteristics of Dry Sliding Surfaces of Particle-Reinforced Aluminum Composites

Generally, friction and wear occur on the surface of the materials. It is necessary to investigate the dry sliding friction and wear behavior of surface. In this paper, 3-D topographical parameters were used to investigate the topographical characteristics of dry sliding surfaces for particle-reinforced alu-minum composites on semi-metallic friction material. The experimental results indicate that the surface topography of the particle-reinforced aluminum composites can be divided into two types, the flaking-off pit type and the groove type. The composites whose surface topography is the flaking-off pit type possess superior heat conductivity and bearing area, lower wear rate, and higher friction coefficient than the groove type. Consequently, the flaking-off pit type surface topography is much better than the groove type for particle-reinforced aluminum composites on semi-metallic friction materials in dry sliding.

矿物掺合料对高性能混凝土收缩分布的影响

为了探索掺不同矿物掺合料高性能混凝土的非均匀收缩特征,采用固定多组位移传感器的方法测试了单面干燥条件下不同深度处混凝土的收缩变形,同时采用湿度传感器监测了各混凝土中相对湿度变化.结果表明:单面干燥条件下,表层混凝土的相对湿度降低和收缩增长速率明显大于内层混凝土,距离干燥表面100 mm处的收缩值比10 mm处低15%～33%.掺硅灰使混凝土内外层收缩梯度明显减小,掺粉煤灰和矿渣粉均使混凝土内外层收缩梯度增大.各矿物掺合料混凝土试件表层和内部的收缩与其相对湿度之间均存在较好的线性关系.

粉煤灰对混凝土内外层非均匀收缩的影响

采用多组LVDT位移传感器,研究了单面干燥条件下不同粉煤灰掺量的混凝土距离表面不同深度处的收缩变形,同时采用埋置湿度传感器的方法测试了不同深度层混凝土中相对湿度变化.结果表明:单面干燥条件下,各混凝土中均存在明显的内外层收缩差和湿度梯度差,且这种收缩变形差随干燥龄期的延长逐渐增大.距离干燥表面任一深度处,混凝土的最终收缩变形和单位相对湿度降低引起的收缩值均随粉煤灰的掺入而减小.掺粉煤灰使混凝土的内外层收缩变形差在开始一周内的增长速率加快,但却使最终收缩梯度差变小.

中国南方碳酸盐岩裸露区表层地震地质条件研究

从岩石力学性质、产生弹性波有效能量理论研究出发,结合中国南方碳酸盐岩裸露区地表地形特点,给出了三个浅地表地质模型。理论上对三个模型表层地震地质条件、地震单炮采集记录品质进行研究和剖析。提出在实际工作中遇到这三个模型中地震资料品质变差时的解决方案,进而提高叠加效果和改善剖面品质,对中国南方碳酸盐岩裸露区进行地震资料采集具有一定的指导意义。通过地震勘探基础研究,无论是对常规油气地震勘探,还是非常规油气地震勘探都是适用的。

DIFFERENCES BETWEEN DRY AND WET SUMMER IN THE VERTICAL MOTION ON NORTH SIDE OF QINGHAI-XIZANG PLATEAU AND THE THERMAL IMPACT OF PLATEAU

To better analyse and understand the causes of Northwest China(NW China)arid climate formation,firstly the dry and wet standards were chosen and the yearly dry and wet grades on the north side of Qinghai-Xizang Plateau(hereafter NSQXP)in summers were classified utilizing the rainfall data of five stations over the area in June-August of 1952—1990.Then the differences between the vertical motion over the Qinghai-Xizang Plateau(QXP)and NSQXP in dry and wet summers were comparatively analyzed using the ECMWF's gridded data of June—August of 1979 —1986.Finally the connection between the QXP surface thermal condition and the dry and wet summers on the NSQXP was discussed as well. The main results are the following:(1)the dry and wet standards taking the rainfall standard deviation as criterion are suitable for the arid climate area;(2)the QXP may be,to some extent. responsible for the environment background of Middle Asia,NW China and North China arid climate areas;(3)there are the striking differences between the dominant vertical motion over the QXP and NSQXP in the dry and wet summers of NSQXP:(4)the QXP surface thermal condition is.to a great extent,responsible for the year—to—year variation of NW China arid climate as well.

单面干燥条件下混凝土的收缩变形分布特征

通过固定多组位移传感器,研究了单面干燥条件下不同水灰比混凝土试件距离表面不同深度处的收缩变形,同时埋置湿度传感器,研究了不同深度处混凝土中相对湿度变化。结果表明:混凝土试件内层(距表面55mm和100mm)的收缩和相对湿度降低明显小于混凝土近表层(距表面10mm)的;水灰比越小。沿混凝土干燥表面垂直方向的收缩与湿度梯度差越大;单面干燥条件下,不同深度混凝土层的收缩与其相对湿度降低值之间均存在较好的线性关系,在达到相同湿度条件时的表层混凝土收缩小于内层混凝土。