民勤沙井子地区沙质荒漠化过程中植被群落物种多样性和排序研究

基于对民勤沙井子地区植被调查数据,研究了不同群落自然植被基本特征,结果表明:丰富度减小是物种多样性变化的主要原因,均匀度指数与多样性指数呈显著的正相关,丰富度指数和均匀度指数呈负相关,CCA和DCCA二维排序说明了植物群落与环境因子的关系,随着地下水位的下降,植被逐渐向强旱生方向演替。     

基于改进ResNeXt50残差网络的锦鲤选美方法

锦鲤选美的不同等级之间具有高相似度的特点,目前都是人工进行选美分级。为解决人工选美所存在的效率低、主观性强、成本高的问题,提出了一种基于迁移学习和改进ResNeXt50残差网络的锦鲤选美方法。本文首先构建了红白、大正、昭和3种锦鲤的选美等级数据集。其次,采用迁移学习策略提高训练速度,并从SE注意力模块、Hardswish激活函数和Ranger优化器3方面对ResNeXt50模型进行了改进,构建了SH-ResNeXt50锦鲤选美分级模型。试验结果表明：SH-ResNeXt50模型有效提升了锦鲤选美的等级分选能力,模型准确率达95.6%,损失值仅0.074,优于常用的AlexNet、GoogLeNet、ResNet50和ResNeXt50网络模型。最后,采用Grad-CAM分析SH-ResNeXt50模型的可解释性,结果表明SH-ResNeXt50模型和人工识别的感兴趣区域基本一致。本文所提出的方法实现了具有高相似度的锦鲤不同等级的智能分选,对其它具有高相似度的生物等级分选具有借鉴意义。     

Guidance of groups of guppies (Poecilia reticulata) to allow sorting by computer vision

Prior to marketing, ornamental tropical fish are currently sorted, graded and counted manually; a process that is labor intensive, stressful to fish and inaccurate. Manipulation of fish movements at our will is a key element in the development of a device for automatically sorting, grading and counting fish by a computer vision system, and the present study is one step towards the development of such a fish-friendly sorting device. The positive phototactic and rheotactic innate responses of guppies (Poecilia reticulata) were exploited to induce them to swim through transparent pipes or narrow channels, to render them ready for inspection by a computer vision system. Water flow direction and velocity, water level, and illumination were effective in inducing fish to move from one container into the other via a narrow transparent pipe. It was attempted to separate guppies moving in groups into individually spaced fish, by introducing an obstacle into a narrow channel or narrowing the transparent pipe.     

Selectivity of flexible size-sorting grid in Mediterranean multispecies trawl fishery

ABSTRACT:   The demersal multispecies trawl fishery in the western Mediterranean Sea has a poor selectivity; large numbers of juvenile fish are caught when using the legislated 40-mm diamond mesh cod end. The selectivity of a flexible sorting grid with 20-mm bar spacing (BS20) installed in front the conventional trawl cod end was investigated. The standard covered cod end method was used. Data was adequate for analyzing the selectivity of European hake Merluccius merluccius , poor cod Trisopterus minutus , greater forkbeard Phycis blennoides and Norway lobster Nephrops norvegicus . The selectivity of the 20-mm sorting grid was compared with the performance of 40-mm diamond (DM40) and square mesh (SM40) cod ends. The effect of a guiding funnel on the performance of the grid (BS20-f) was also explored. Finally, the potential changes in yield per recruit (Y/R) and biomass per recruit (B/R) after implementing a sorting grid were explored. An overall improvement in the 50% selection length ( L ₅₀ ) with all four species was substantial when comparing the BS20 to the DM40. Higher improvement in L ₅₀ s was achieved when the grid was equipped with the guiding funnel. When comparing the performance of the BS20-f to the SM40, there was no marked difference in L ₅₀ s. The Y/R and B/R, however, are substantially higher with BS20-f for poor cod and about the same for European hake. BS20 compared to SM40 achieved lower Y/R and B/R for all four species; the smallest difference was observed for Norway lobster. Further development is required if the sorting grid is to be introduced into commercial fisheries.     

废纸制浆固废物成分分析及分拣

以废纸制浆过程中产生的废渣为研究对象,采用“四分法”取样。通过分析样品中的成分构成及各成分比例,探讨其应用于木塑复合材料的可行性。分析结果显示,固体废弃物中主要成分为塑料和植物纤维废渣,两者占总重的80wt%以上;聚丙烯（PP）和聚乙烯（PE）占塑料总重的55wt%以上;采用水浮法可实现废渣原料的分拣。     

不同播期、密度和肥料对菜用板蓝根产量及品质的影响

为探索菜用板蓝根在毕节地区的优质高产栽培措施,通过田间试验研究菜用板蓝根不同播期、密度和氮钾肥施用量对产量及品质的影响。结果表明,在毕节地区,菜用板蓝根适宜播期为4月30日左右,种植密度为50．025～66．70万株/hm2,钾肥施用量为150～300 kg/hm2,氮肥施用量为778 kg/hm2左右,在此栽培条件下,产量可达73947．96～76749．35 kg/hm2,且品质较好,蛋白质、脂肪、水溶性糖及维生素含量较高,粗纤维含量较低。     

黄芪对鲤头肾中巨噬细胞的增殖和一氧化氮产量的影响：离体研究

用密度梯度离心分离鲤头肾中的巨噬细胞和嗜中性粒细胞。用RPMI细胞培养液对分离的细胞进行原代培养,在细胞培养液中加入不同浓度的黄芪水提取液来研究黄芪对鲤头肾中免疫细胞非特异性免疫应答的影响。黄芪水提取液单独使用时能刺激鲤头肾中巨噬细胞的增殖,但不能刺激巨噬细胞的氮暴发活性。用黄芪和脂多糖(LPS)混合刺激巨噬细胞和中性粒细胞时,黄芪水提取液能显著提高脂多糖刺激所产生的一氧化氮的产量。研究结果表明,黄芪不仅能刺激巨噬细胞数量的增加,而且能协同脂多糖增强头肾中免疫细胞的功能,从而对机体的非特异性免疫起调节作用。     

牛膝细胞转化苗的田间培植

经过近1年的实验室工作,于1997年5月得到发育良好的牛膝细胞转化苗.1997年6月将室内培植14日的6棵幼苗移栽至田间.种植1O日后去弱保留3棵.1997年1O月收获种子.一部分留样,一部分于1998年5月进行田间播种,扩大种植.     

拨辊推送式马铃薯清选分选机设计与试验

针对现有马铃薯清选分选机的薯土分离效果差、伤薯率较高、工作效率低等问题,设计了一种拨辊推送式马铃薯清选分选机。对该机器的工作机理进行了阐述,确定了清选装置、分选装置的结构参数,分析了马铃薯在清选分选过程中的力学特性。选取机组的转速、上料量、机组提升角度作为试验因素,伤薯率、分选清洁率为试验性能指标进行正交试验,并对试验结果进行显著性分析。结果表明,各因素对伤薯率影响的主次因素顺序为:机组提升角度、机组转速和上料量;对分选清洁率的影响主次因素顺序为:上料量、机组转速和机组提升角度。按照以马铃薯的伤薯率较低,兼顾分选清洁率较高的原则,确定较优组合,即机组转速为145 r/min,上料量为20 t/h,机组提升角度为12°,并对该参数组合进行了验证试验,结果表明,在该条件下机器伤薯率为0.773%,分选清洁率为95.42%,符合基本作业要求。     

回转带精选大豆的试验研究

大豆精选主要是去除虫伤破嘴豆、虫眼豆等杂质,提高大豆的整齐度和纯净度。为此,运用二次通用旋转组合设计方法进行了优质大豆与虫伤破嘴豆的分选试验,建立了试验因素与试验指标间的回归数学模型。通过观察分析该装置对含有各种杂质的大豆的精选效果,为进一步研究精选装置、达到高精选率奠定了基础。试验表明,回转带式分选装置可有效去除大豆中的虫伤破嘴籽粒,但对洞口很小的虫眼豆精选效果不理想,需进一步研究。