SAR图像组合分割算法

由于存在乘性斑点噪声的影响,给SAR图像分割造成很大困难,本文研究利用最大似然区域增长分割算法,提出区域增长前引入自适应边缘检测,图像分割性能获得较大提高.介绍了我们研究的分割性能优异的模拟退火分割算法,提出了分割性能接近模拟退火并且在SAR图像分割中比较实用的模拟退火和最大似然混合分割算法,并给出了这些分割算法的分割性能比较,以及在实际分割SAR图像时应当如何选择分割算法.     

Cut‐off Frequencies Induced by the Length of Strain Gauges Measuring Impact Events

Abstract: The finite length of strain gauges may induce filtering effects when measuring impact events. In this study, we are interested in quantifying these effects. Precisely, we determined the cut‐off frequencies of strain gauges cemented on visco‐elastic bars and measuring impact‐induced strain waves. This study shows that the cut‐off frequencies increase with the bar’s wave velocity and decrease with the bar’s diameter. The asymptotic value, corresponding to an infinite bar diameter, is reached rapidly (bar diameter ≈ 15 mm). Moreover, we showed that the mode cut‐off frequencies are more severe (lower) than the gauge length cut‐off frequencies for bar diameters greater than 8 mm.     

Scalable Production of Biomedical Microparticles via High-Throughput Microfluidic Step Emulsification

Drug microcarriers are widely used in disease treatment, and microfluidics is well established in the preparation of microcarrier particles. A proper design of the microfluidic platform toward scalable production of drug microcarriers can extend its application values in wound healing, where large numbers of microcarriers are required. Here, a microfluidic step emulsification method for the preparation of monodisperse droplets is presented. The droplet size depends primarily on the microchannel depth rather than flow rate, making the system robust for high-throughput production of droplets and hydrogel microparticles. Based on this platform, basic fibroblast growth factor (bFGF) is uniformly encapsulated in the microparticles, and black phosphorus (BP) is incorporated for controllable release via near-infrared (NIR) stimulation. The microparticles serve as drug carriers to be applied to the wound site, inducing angiogenesis and collagen deposition, thereby accelerating wound repair. These results indicate that the step emulsification technique provides a promising solution to scalable production of drug microcarriers for wound healing as well as tissue regeneration.     

Objective yarn bulk measurement through image analysis

A novel objective yarn bulk measurement method has been developed through image analysis technique. Two orthogonal images are taken from the same part of a yarn and then transformed into gray scale. Each gray scale image is further processed separately by extracting the yarn image from background with the help of intensity histogram using adaptive threshold. This gives rise to a binary image which is used as input for the second part of the algorithm measuring yarn volume. The processing on the input image starts with omitting the long rare loops, considered as noise, by morphological operations. This is followed by measuring the width of the two orthogonal images pixel by pixel along the yarn. Finally, the total volume of the yarn is ascertained by integrating the volume of all the individual imaginary ovals with their two diameters replaced by the two widths of orthogonal images at the corresponding pixel.     

离轴三反空间相机的焦距测量

离轴三反光学系统的焦距是空间相机的重要指标之一,离轴三反空间相机在完成光学系统装调及光学镜头装配后需要进行焦距测量。通过对两种经典的焦距测量方法即放大率法和测角法进行对比分析,选用测角法作为焦距的测量方法,同时对用于同轴光学系统的焦距测量公式增加离轴角修正量使其适用于离轴三反光学系统,并以某离轴三反空间相机为例论述焦距测量方法及步骤。由修正后的焦距计算公式计算出相机的焦距为8 010mm,证实了该测量方法的可行性。     

外形要求下径向磁力轴承的参数分析

在列举了几种径向磁力轴承的典型外形要求后，以满足外形要求为前提，得出几组结构参数的变化，并分析这几组参数各自对磁力的影响。从而对比各组参数的优劣及其适用情况，便于径向磁力轴承的结构设计及设计结果的更改。     

Cow characteristics and their association with production performance with different dry period lengths

Shortening or omitting the dry period (DP) has been proposed as a management strategy to improve energy balance of dairy cows in early lactation. Both shortening and complete omission of the DP reduces milk production in the subsequent lactation compared with a conventional DP length of 60 d. Some cows have less milk production loss than other cows after applying no DP or a short DP. The aim of this study is to evaluate which cow characteristics are associated with the amount of milk production losses following no DP or a short DP (30 d). Daily production information from the lactation before and after the DP was available from 161 dairy cows (54 cows with a 0-d DP, 51 cows with a 30-d DP, and 56 cows with a 60-d DP) from a research herd. Daily production (milk, fat, and protein) until 305 d in milk was estimated for all cows. Subsequently, total fat- and protein-corrected milk yield from 60 d before the expected calving date until 305 d in the following lactation (FPCM_total) was estimated. A statistical analysis was performed to evaluate which cow characteristics were associated with limited or no production losses following no DP or a short DP, compared with a conventional DP length of 60 d. Average FPCM_total was 9,341, 10,499, and 10,795 kg for cows with no DP, a 30-d DP, and a 60-d DP, respectively. The cow characteristics parity, daily milk production at 12 wk before the expected calving date, and reduction in daily milk production between 16 and 12 wk before the expected calving date were associated with production loss due to a short (30 d) or no DP. Compared with 60 d DP, multiparous cows had less production loss (987 kg) following no DP than primiparous cows (2,132 kg). The difference in FPCM_total between the 3 DP groups was largest for cows with a low milk production (e.g., 10 kg/d) at 12 wk before the expected calving date. The greater the reduction in milk production between 16 and 12 wk before the expected calving date, the larger the difference in FPCM_total between the 3 DP groups. The difference in FPCM_total between cows with no DP and 60 d DP at a reduction in milk production between 16 and 12 wk of 10% was 665 kg, whereas this difference was 1,138 kg at a reduction of 70%. The cow characteristics found can be used to select cows for specific DP lengths in a decision-support model to support the farmer on the economic optimal DP length for each individual cow. Output of such a decision-support model can be, for instance, to advise a 30-d DP for multiparous cows with high milk production (e.g., 25 kg/d) at 12 wk before the expected calving date.     

淀粉替代剂在双胶纸中的应用

探讨了淀粉替代剂部分替代淀粉进行表面施胶,使双胶纸质量有一定提高,并降低了生产成本。实验表明,当淀粉替代剂替代比例为20%时,方案最佳,吨纸成本可节约22.09元,胶液成膜性比未使用替代剂要好,而且成纸的表面强度和裂断长分别比未使用替代剂时提高21%（正面）/17%（反面）和24%,透气度也有所降低,平滑度与之前相当,表面施胶剂烷基烯酮二聚体（AKD）的用量比未使用替代剂时节约3.1 kg/t（纸）。     

Study on flock detaching motion of a cotton comber

Flock detaching motion is an important factor of the combing quality of a cotton comber. A model for flock detaching time and detaching roller motion was developed by analyzing the motion of the nipper during the flock detaching process. Then, a diagram for the relationship between flock detached time parameters and a graph for detaching roller speed were drawn. This study provides a theoretical basis for analyzing combing quality and designing detaching roller motion.     

青钱柳-葛根复合发酵型饮料发酵工艺优化

以青钱柳液和葛根汁为原料,加入酵母菌和植物乳杆菌植物亚种（Lactobacillus plantarum subsp. plantarum）,进行分步发酵生产青钱柳-葛根复合发酵型饮料。在单因素试验的基础上进行正交试验,优化青钱柳-葛根复合发酵型饮料发酵工艺。结果表明,青钱柳-葛根复合发酵型饮料最佳的发酵工艺为：青钱柳液与葛根汁比例1∶1（V/V）,酵母接种量0.5%,一次发酵时间24 h,植物乳杆菌植物亚种接种量3.5%,二次发酵时间16 h。在此优化发酵工艺条件下,青钱柳-葛根复合发酵型饮料具有青钱柳和葛根的清香味,口感柔和,酸甜适口,感官评分达91.7分,酒精度为0.2%vol,总酸含量为2.49 g/L,糖度为8.3 °Bx,pH值为3.58,总黄酮含量达5.15 mg/g。