Bolted connections have become the most widely used connection method in steel structures. Over the long-term service of the bolts, loosening damage and other defects will inevitably occur due to various factors. To ensure the stability of bolted connections, an efficient and precise method for identifying loosened bolts in a given structure is proposed based on computer vision technology. The main idea of this method is to combine deep learning with image processing techniques to recognize and label the loosening angle from bolt connection images. A rectangular steel plate was taken as the test research object, and three grade 4.8 ordinary bolts were selected for study. The analysis was conducted under two conditions: manual loosening and simulated loosening. The results showed that the method proposed in this article could accurately locate the position of the bolts and identify the loosening angle, with an error value of about ±0.1°, which proves the accuracy and feasibility of this method, meeting the needs of structural health monitoring.
以胡萝卜缨为主要原料,制备蔬菜包装纸.通过单因素试验和响应面试验研究黄原胶、羧甲基纤维素钠、明胶和大豆改性磷脂的添加量对胡萝卜缨蔬菜包装纸感官评价的影响,确定蔬菜包装纸制备的最佳工艺.实验结果表明:黄原胶添加量为0.49％、羧甲基纤维素钠添加量为0.31％、明胶添加量为0.21％、大豆改性磷脂添加量为0.42％时,胡萝卜缨蔬菜包装纸色泽均匀、翠绿有光泽、表面平整、易揭.本研究为新型胡萝卜缨蔬菜包装纸的制备提供了理论依据.
益生菌及其代谢产物具有抑制炎症、改善肉鸡抗氧化与免疫功能的作用.本试验旨在研究复合益生菌制剂(CPP)对脂多糖(Lipolyaccharide,LPS)感染肉鸡肠道健康的影响.试验选取30只体重均一且健康的AA肉鸡,平均分到3个处理组.对照组与LPS感染组的肉鸡饲喂基础日粮,LPS+CPP组肉鸡采食的日粮中添加100 mg/kg CPP.试验为期28 d,于试验结束时LPS与LPS+CPP组肉鸡腹腔注射LPS,对照组肉鸡注射等体积的生理盐水.结果显示:与对照组相比,LPS处理提高血清二胺氧化酶(Diamine oxidase,DAO)的活力,降低血清超氧化物歧化酶(Total superoxide dismutase,T-SOD)与空肠总抗氧化能力(Total antioxi-dant capacity,T-AOC)的含量(P＜0.05).此外,LPS处理显著下调空肠与回肠绒毛蛋白(villin)与黏蛋白(Mucin-2)的转录水平,上调空肠与回肠IL-1β、TNF-α的mRNA水平(P＜0.05).日粮中中添加CPP可提高空肠的相对长度与回肠的相对重量(P＜0.05).此外CPP可缓解LPS引起的血清DAO活力;空肠IL-1β、IFN-γ与回肠IL-1β转录水平的上调;缓解LPS引起的血清T-SOD水平的下调(P＜0.05).综上所述,日粮中添加复合益生菌制剂可缓解脂多糖对肉鸡肠道健康的负面影响.
研究生大量的阅读专业文献是获取主要的研究内容来源之一.研究生在几年的学习中,其重要的考核便是以形成学术论文的形式呈现自身的学习成果,而论文中的参考文献则是对研究生学习态度、学习视域、学习方向及学术诚信的重要考察因素.本研究主要探讨研究生在学术论文中对于参考文献的认知误差及隐藏的种种学术不端行为,并就此提出必须加强研究生的自觉自律及学术规范的培养;加强研究生导师对论文的指导责任;开展学术论文写作及学术论文规范化的讨论与交流,让学术规范与诚信意识深入学生心中并使之化为严谨的科研行为习惯.
为了解江西省南昌市市售米面食品中克罗诺杆菌的污染状况、毒力基因特征以及耐药性情况,利用PCR扩增技术和16S rDNA测序分析对克罗诺杆菌进行鉴定,并对5种毒力基因进行扩增,同时通过肉汤微量稀释法对菌株进行8种抗生素的药敏试验.结果显示在68株克罗诺杆菌中,有47株属于阪崎克罗诺杆菌,检出率为68.12％,有10株属于丙二酸盐克罗诺杆菌,检出率为14.49％.阪崎克罗诺杆菌中的cpa基因检出率最高,为91.49％,其他依次为aut(80.85％)、hly(68.09％)和inv(42.55％),sip未检出;丙二酸盐克罗诺杆菌中则是aut基因检出率最高,为80％,另外cpa基因也有检出,检出率为30％,其他3种毒力基因均未检出.阪崎克罗诺杆菌中同时携带两种以上毒力基因的比例达到91.49％.克罗诺杆菌对于8种抗生素的耐药率普遍较低,阪崎克罗诺杆菌仅有2株对氨苄西林表现出耐药性,耐药率为4.26％,有1株同时对头孢曲松和头孢噻肟表现出耐药性;丙二酸盐克罗诺杆菌中仅有2株对呋喃妥因表现出耐受性.研究结果可为米粉及面条中食源性致病菌的风险评估提供一定的参考和数据支持.
