采用Fluo-3 AM-ester探针研究桃不同组织的Ca^2＋信号分布

钙作为植物最重要的矿质元素之一,在植物生理和生化活动中起重要作用。采用激光扫描共聚焦显微镜,以Fluo-3 AM-ester为荧光探针研究了桃果肉和叶柄组织中Ca2＋的分布,结果表明Fluo-3 AM-ester可作为荧光探针对桃不同组织中游离的Ca2＋信号强度和分布特征进行分析。不同的物镜观察（10×和20×）下,C...     

Sedimentary aggregates in the Peoria Loess of Nebraska, USA

Loess grain size data used to infer transport direction or wind strength are generally derived from vigorously disaggregated samples. However, these data may not adequately represent the effective particle size distribution during loess transport, if the transported dust contained aggregates of fine-grained material. Thin sections of minimally altered C and BC horizons in the late Pleistocene Peoria Loess of Nebraska, USA, indicate the presence of aggregates with diameters of 30–1000 μm. The larger aggregates (>250 μm) are unlikely to have been transported, and are interpreted as the result of soil faunal activity and other pedogenic processes after deposition. Aggregates smaller than 250 μm could have a similar origin, but laser diffraction particle size analysis suggests that many are sedimentary particles. Comparison of minimally and fully dispersed particle size distributions from each sampling site was used to estimate the modal diameter of aggregates. The aggregate modal diameter becomes finer with decreasing loess thickness, representing increasing distance from the source. A similar trend was observed in the modal diameter of fully dispersed particle size distributions, which represents the mode of sand and silt transported as individual grains. We interpret both trends as the result of sorting during transport, supporting the interpretation that many of the aggregates were transported rather than formed in place. Aggregate content appears to increase with distance from the source, explaining a much more rapid downwind increase in clay content than would be expected if clay were transported as particles smaller than 2 μm diameter. Although the Peoria Loess of Nebraska contains sedimentary aggregates, many of the coarse silt and sand grains in this loess were transported as primary particles, were thoroughly exposed to sunlight and are potentially well suited for luminescence dating.     

混联机床并联轴定位精度的激光测量与误差补偿

在分析混联机床并联轴定位精度的激光干涉测量原理和方法的基础上,采用干涉法检测了并联轴Z向的定位精度和重复定位精度,做出了并联轴的平均偏差特性曲线,获得了其线性位移定位误差数学模型;利用最小二乘法得到了混联机床并联轴定位误差补偿模型和增量补偿特性曲线;推导了并联机构动平台位姿和各驱动杆杆长的求解过程,进而对混联机床并联轴定位精度进行了有效补偿,得到了一种并联轴定位精度激光干涉测量方法和误差补偿模型的建立方法.     

曲轴激光喷丸强化数值仿真

采用数值仿真的方法,研究了激光冲击强化对175A型柴油机曲轴疲劳寿命的影响,取得了数值仿真条件下曲轴过渡圆角处残余应力场的数据,数值仿真结果和实验结果的对比分析表明:数值仿真结果和实验结果较为接近,从而验证所采用的材料本构模型、冲击波峰值压力和冲击波作用时间是精确的.通过此类激光冲击强化仿真分析,可优化激光冲击的相关参数,使曲轴过渡圆角产生有利的残余应力场,从而为激光冲击强化曲轴提供优化的工艺参数.     

铁皮石斛miR168分子进化特征及响应蓝激光表达分析

笔者在关于铁皮石斛miRNA组学研究中发现较多响应蓝激光的miRNA,挑选关键且差异表达的miR168进行分子进化特征及其响应蓝激光表达分析。经对前体和成熟体分类统计、进化树构建、靶基因预测、启动子顺示作用元件及响应不同光质表达等进行分析,结果显示：miR168家族成员分布在40个植物物种中,前体和成熟体成员较少,其在植物中可能进化得不够完整;物种特异性是影响miR168前体进化特性的重要因素,而序列保守性是影响成熟体进化特性的主要因素;由3p臂上形成的miR168成熟体序列有较高特异性、5p臂形成的成熟体的序列保守性较高;Mfold和Rfam预测表明铁皮石斛miR168茎序列的保守性高于环序列,前体发卡结构较多,成熟体位置位于3p臂上,既包含茎序列也包含环序列;铁皮石斛miR168a的启动子主要包括光、激素、生物和非生物胁迫响应元件,可能通过这些顺式元件在其响应蓝激光中起调控作用;铁皮石斛响应蓝激光的靶基因主要包括ABC转运蛋白B家族成员、乙酰辅酶 A 乙酰转移酶等,主要参与植物生长发育和响应外界因素。实时荧光定量PCR结果表明,铁皮石斛miR168a与其靶基因gene-MA16_Dca006149、gene-MA16_Dca020995、gene-MA16_Dca017821参与蓝激光对铁皮石斛的影响。     

Measurement of enteric methane from ruminants using a hand-held laser methane detector

Abstract

This study investigated the effectiveness of the proprietary laser methane detector (LMD) in enteric methane monitoring from individual dairy cows and sheep. Three experiments were carried out. First, the relationship between LMD and indirect open-circuit respiration calorimetric chamber measurements was tested. Sensitivity and specificity for cows were 95.4% and 96.5%. For sheep, sensitivity was 93.8% and specificity was 78.7%. Second, the effect of cow's activity on enteric methane emissions was investigated. During drinking and feeding, cows produced significantly more (p<0.001) methane emissions than when idle. Third, effect of different micrometeorological factors on LMD measurements under outdoor grazing conditions was investigated. Wind speed, relative humidity, pressure and wind direction relative to methane point-source had significant effect on methane measurements (p<0.001) under outdoor conditions. With further validation, the LMD has potential to provide reliable estimates from ruminants and hence provide a useful technique for on-farm monitoring and decision support for greenhouse gas mitigation strategies.     

基于激光拉曼光谱的脐橙内部品质无损检测

论文初步探讨了运用激光拉曼光谱技术来检测脐橙内部品质的方法。应用激光拉曼光谱仪获取脐橙拉曼谱线,通过对拉曼谱线处理与分析得到了预测脐橙果肉糖度和硬度的谱线特征值,以四个谱线特征值为输入参数、脐橙糖度和硬度为输出建立了三层BP神经网络模型。结果表明,模型的糖度预测值与实测值之间的误差总体方差为0.0656,模型的硬度预测值与实测值之间的误差总体方差为0.0062。研究表明,采用激光拉曼光谱技术检测脐橙内部品质是可行的。     

激光辐照水与水仙花对水仙花生长影响研究

[目的]研究激光辐照水和水仙花对水仙花生长的影响。[方法]以金盏银台水仙花为材料,以无辐照处理为对照,用He-Ne激光器分别以辐照强度0.75、1.20、1.50和1.80 mW对4组水仙花的水培养液和另外4组水仙花辐照处理5、10、15、20和25 min,研究各处理水仙花的生长发育情况。[结果]各辐照处理的水仙花叶长、叶宽、花瓣直径、花茎直径、开花时间等都好于CK。0.75 mW激光辐照水仙花对水仙花生长的促进作用比较明显;在5~20 min,水仙花叶长、叶宽、花瓣直径、花茎直径随1.20 mW激光照射时间的延长而增加;在5~25 min,水仙花叶长、叶宽、花瓣直径、花茎直径随1.50 mW激光照射时间的延长先增大后减小;1.80 mW激光照射抑制水仙花生长。[结论]低强度激光辐照可促进水仙花生长。     

Emulator of A-bucket Algorithm applying to the Surface Detection

An important problem in phase-shifting interferometry is to get rid of the phase-shift error in order to enhance the measurement accuracy. In this paper, a new method that can be used to calculate the real phase-shift from the interference pattern is proposed and emulated.     

Parallel Optical Method in Laser Speckle Velocimetry and Particle Image Velocimetry

A method of parallel optical processing of double exposure specklegram or particle image using hololens array is presented.It can greatly decrease the processing time because the mechanical moving time of the X Y translation stage is decreased by tens of times.