物流非高斯振动下的产品损伤分析

公路运输过程中的冲击信号造成了物流随机振动的非高斯特性。为研究冲击成分对产品损伤的影响,对8条中型卡车和重型卡车实测道路信号进行了统计分析。将振动信号分为20%的高强度非高斯信号、60%的中等强度高斯信号和20%的低强度高斯信号。使用有限元软件进行时域振动分析,计算各信号段的损伤占比。结果表明:振动过程中,非高斯信号蕴含了高强度的冲击信号,造成了绝大部分的损伤。中型卡车振动数据冲击幅值大、占比少,相对而言,重型卡车冲击幅值低、占比多。中型卡车高5%的冲击信号造成了90%以上的损伤;重型卡车20%的非高斯信号中除10%的冲击成分外还包含10%的较高幅值振动,其20%的非高斯信号造成的损伤约为80%或更高。在整个运输振动过程中,含量较少的冲击信号主导了损伤的累积。

基于地下水位插值与遥感解译的盐碱化等级划分

为探明受地下水位影响的干旱荒漠区土地盐碱化形成概率,选取甘肃省景泰川电力提灌工程灌区为研究区,以1994、2001、2015年TM影像数据与年均地下水埋深数据为本底数据,采用Arc GIS监督误差分类法对区域遥感影像进行不同程度盐碱地提取分类,运用克里金空间插值将实测地下水位进行空间转换,在此基础上,将分类结果和插值结果通过重分类消除量纲并进行等权重合并,同时把合并结果等间距分5级来表示受地下水位影响土地盐碱化形成概率。结果表明:1994-2015年灌区盐碱地呈现扩张趋势,增长率为61.87%,年均增长率为2.95%;地下水插值结果显示区域内整体地下水位抬升,年均抬升量为0.125 m,东北部地下水位变化最为剧烈;自西南到东北部土地盐碱化形成概率等级逐渐增加,土地等级转变较为明显,盐碱化等级为1、2级的土地明显增加,水位抬升对土地盐碱化等级增加影响突出。研究可为干旱荒漠区区域地下水利用提供理论依据。

碱溶性茯苓多糖的抗氧化作用

以九资河茯苓为原材料制备碱溶性茯苓多糖,通过傅里叶红外光谱和紫外可见分光光谱扫描对其结构进行初步表征,并评价其对超氧阴离子自由基、羟基自由基和DPPH自由基的清除能力。结果表明,碱溶性茯苓多糖显示出多糖的典型特征吸收峰为β型多糖;其体外抗氧化能力整体随碱溶性茯苓多糖浓度的升高而增大,当碱溶性茯苓多糖浓度为1.0 g/L时,超氧阴离子自由基和羟基自由基清除率达到最大,分别为63.27%和62.32%,且在此浓度下碱溶性茯苓多糖具有最大还原能力,吸光值为0.51;多糖浓度为0.8 g/L时,DPPH自由基清除率达到最大值,为61.21%。综上所述,碱溶性茯苓多糖具有良好的体外抗氧化能力,具有深入研究及开发的潜力和价值。

Experimental investigation on debris flow resistance and entrainment characteristics:effects of the erodible bed with discontinuous grading

Debris flow deposits in natural channels typically have a wide grain size distribution(GSD).The effects of bed sediment GSD on the basal entrainment rate are neglected in current debris flow erosion models.Field investigations have detected three different vertical graded bedding structures:normal,inverse,and mixed-gradation,characterized by discontinuous gradation sediment and almost without intermediate-sized particles.This study conducted small-scale flume experiments to investigate the debris flow resistance forces and entrainment characteristics by incorporating the effects of discontinuous grading bed sediments.Discontinuous graded bed sediments with varying fine particle content,volumetric water content(VWC),and roundness were designed for comparison.Debris flow resistance in erodible beds generally increased in the group with gravel of larger-sized coarse particle,lower roundness,and higher bed sediment VWC.For discontinuous grading bed sediment,the entrained depths increased in the group with gravel of smaller coarse particle sizes,larger amounts of fine particles,and higher sediment roundness,and decreased with larger VWCs.This abnormality may be attributed to the disproportionately large effects of viscous flow resistance in our small-scale flume tests.The maximum erosion rates of the continuous bed sediment were higher than those of the corresponding discontinuous bed sediment with the same maximum coarse gravel size.This is because,for discontinuous grading bed sediments,localized failure of intermediate-sized sediment grains may cause a large-scale collapse of the solid grain skeleton and enhance basal entrainment rates.A revised formula for calculating the debris flow entrainment rate is proposed by incorporating the kurtosis coefficient,which describes the distribution of discontinuous bed sediments and fine particle content.Our revised formula could facilitate an elaborate estimation of basin erosion and sediment runoff and reveal the development and recession of debris flow fans.

单片机在高职传感器课程教学上的应用研究

通过对传统的传感器课程教学的分析,找出其教学方法单一,学生感觉内容抽象枯燥,学习积极性不高的问题,提出在课程中引入单片机知识,基于项目化教学,将传感器知识与单片机知识相结合,让高职学生更好地学习掌握这门课程,提高学生的学习兴趣。

Crystal Structure and Bovine Serum Albumin Binding Studies of Methyl 4-(2,4-Dichlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate

The title compound, methyl 4-(2,4-dichlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate(C_(20) H_(21)Cl_2NO_3, 1) was synthesized and the crystal structure was —determined by single-crystal X-ray diffraction. It crystallizes in tetragonal system, space group P421 c with a = 16.076(3), b = 16.076(3), c = 14.750(2) ?, V = 3811.8(14) ?3, Z = 8, R = 0.0377 and wR = 0.0845. The interactions between compound 1 and bovine serum albumin(BSA) were investigated using fluorescence spectroscopy. The results revealed that compound 1 can effectively quench the intrinsic fluorescence of BSA by static quenching mechanism. The thermodynamic parameters revealed that the action forces between compound 1 and BSA were mainly van der Waals forces and hydrogen bonds. According to F?rster's non-radioactive energy transfer theory, the binding distance between compound 1 and BSA had been determined. Furthermore, the synchronous fluorescence showed that compound 1 has few effects on the microenvironment and conformation of BSA in the binding process.

Optical Transition Radiation Measurement of Electron Beam for Beijing Free Electron Laser

We used transition radiation techniques instead of the original phosphor targets to improve the electronic beam diagnostic system at Beijing Free Electron Laser.The beam profile,size(3.3×2.4mm),position and divergence angle(σrms=2.5mrad)in transverse have been obtained from optical transition radiation.We also present the experimental set-up and some preliminary results.

异烟肼缩2-羟基-1-萘甲醛酰腙Ni^(2+)荧光探针的研究

由2-羟基-1-萘甲醛与异烟肼缩合得到异烟肼缩2-羟基-1-萘甲醛酰腙(探针1)。荧光光谱实验表明:探针1是一种选择好、灵敏度高的Ni^(2+)荧光探针。当Ni^(2+)浓度在0~20μmol/L范围内,Ni^(2+)的浓度与探针1(10μmol/L)的荧光强度之间呈较好的线性关系,检出限为5.10μg/L。Job实验表明:Ni^(2+)与探针1的络合比为11,结合常数为7.83×103L/mol。