面向分拣机器人的珍珠形状视觉检测方法

针对人工进行珍珠形状分拣效率低、精度不稳定等问题,提出基于机器视觉的珍珠形状检测方法;采用背光成像方式消除珍珠表面纹理和光泽的影响,对获取的珍珠图像进行同态滤波等预处理算法,提高图像对比度;为了解决相互接触珍珠影响珍珠轮廓提取的问题,采用分水岭算法对珍珠图像进行分割,得到了独立存在的珍珠个体,再通过连通域标记、质心算法对珍珠进行定位;根据国家标准对珍珠形状的规定,基于珍珠图像信息建立珍珠形状参数模型,对珍珠形状进行量化;实验结果表明,不同形状的珍珠样本的检测误差为0.63%,形状统计精度为100%,算法耗时24 ms;该方法可准确高效地对珍珠进行分拣分级,具有一定的实用价值。     

结合位图切割和区域合并的彩色图像分割

就经典分水岭图像分割算法中存在的过分割问题，提出一种结合位图切割和区域合并的彩色图像分割算法。对原始彩色图像通过空域梯度算子求其梯度图像，并利用位图切割重建梯度图像；对新梯度图像进行分水岭预分割；对预分割图像基于异质性最小原则进行区域合并，并获得最终分割结果。相比于现有的同类方法，该算法引入位图切割，抑制噪声对分割结果的影响，在边缘模糊处分割准确，得到符合人类视觉的较小分割区域数目，同时在运行效率上提高。     

Visually deficient working conditions and reduced work performance in office workers: Is it mediated by visual discomfort?

IntroductionThe main purpose of this cross-sectional study was to investigate whether visual discomfort acts as a mediating factor between perceived visual ergonomic working conditions and self-rated visual performance among office workers who carry out administrative tasks and computer-based work at the Swedish Tax Agency.MethodsA questionnaire was sent to 94 office workers addressing: 1) perceived visual quality of the visual display units; 2) prevalence of eye symptoms; and 3) self-rated visual performance. Eighty-six persons (54 women (63%), 31 men (36%), and 1 of unspecified sex) answered the questionnaire. Multiple regression analysis investigated the association between visual ergonomic working conditions and visual performance, both with and without visual discomfort as a mediator.ResultsThe group mean of the Indexed survey questions indicated a reasonably good quality of visual ergonomic working conditions, a relative absence of eye symptoms, and acceptable self-rated visual performance. Results from multiple regression analysis showed a significant association between perceived visual ergonomic working conditions and self-rated visual performance (r² = 0.30, β = 0.327, p < 0.01). When visual discomfort was used as a mediator, the association between perceived visual ergonomic working conditions and self-rated visual performance remained the same (r² = 0.32, β = 0.315, p < 0.01).DiscussionIt was remarkable to discover that self-rated visual performance was independent of visual discomfort. Possible explanations include exposure factors not included in the current study, such as dry air and sensory irritation in the eyes, psychosocial stress, time spent performing near work activities, or time exposed to visually deficient working conditions.Relevance to industryThe strong connection between satisfaction with visual ergonomic working conditions and productivity in this study has implications for workplace profitability and staff satisfaction. If productivity is enhanced by better visual ergonomic working conditions, then managers of workplaces may be able to improve work outcomes by optimizing the physical work environment.     

一类Hilfer型分数阶微分方程解的存在和唯一性

用Banach不动点定理和上下解方法研究了α(1<α <2)阶数和β(0≤β ≤1)类型Hilfer分数阶微分方程的解,给出了方程解的存在和唯一性,并通过例证验证了本文所得结果的有效性.     

综放工作面上隅角瓦斯治理技术实践

为解决瓦斯矿井综放面推采过高瓦斯区域时,上隅角瓦斯易超限的问题,结合赵庄二号井2309工作面地质情况,研究实施了工作面采空区瓦斯抽采和上隅角软管抽放的综合治理技术。实践表明:在2309综放工作面回采期间,上隅角瓦斯浓度得到有效控制,平均为0.15%,最高为0.36%,为工作面安全生产提供了有力保障。     

上水口环形吹氩对中间包内渣眼形成的影响

 中间包上水口环形吹氩可以在塞棒周围形成清洗钢液的环形气幕，同时部分氩气泡随钢液进入上水口内，可以减少非金属夹杂物在水口内壁的黏附，起到防止水口堵塞的作用。然而，不合理的吹氩量会导致中间包内液面渣层受过强的气液羽流冲击而形成渣眼，使得钢液裸露并发生二次氧化，严重影响铸坯质量。采用标准 k ε 湍流模型研究中间包内流体流动，采用DPM模型和VOF模型耦合方法，研究上水口环形吹氩条件下渣眼的形成及演化规律。结果表明，上水口环形吹氩在塞棒周围形成较强的上升流，塞棒上部邻近区域存在多个涡流区；在钢液涡流的影响下，中间包液渣下层远离塞棒区域，上层向塞棒区域迁移；随着吹氩量的增大，平均湍动能增大，塞棒附近钢液速度逐渐增大，钢渣界面钢液速度先增大后减小，渣眼边缘钢液速度先增大后减小然后再增大，速度与垂直方向夹角逐渐减小；增大吹氩量，中间包熔池液面形成以塞棒为中心的渣眼，渣眼面积逐渐增大。试验条件下不产生渣眼的临界吹氩量为4.2 L/min，对应的钢渣界面最大速度为0.247 m/s，与垂直方向夹角为70°。     

上保护层开采底板破坏深度和应力分析研究

上保护层开采导致的底板变形、应力释放会使被保护层内高瓦斯沿着上覆岩层内形成的空隙裂隙结构向上运移，很容易造成所采工作面采空区内瓦斯增加，造成工作面瓦斯超限。以峰峰集团以黄沙矿为研究实例，针对其主采的2号煤层利用FLAC^3D模拟软件进行上保护层开采底板应力研究，揭示了上保护层开采底板应力的规律特性，对于保护层开采工作瓦斯治理具有一定的指导意义。     

浅谈煤与瓦斯突出矿井"U"型通风系统采煤工作面上隅角瓦斯管理

屯兰煤矿是煤与瓦斯突出矿井,瓦斯涌出量大,上隅角瓦斯治理困难。为解决这一通风难题,该矿采取沿空留巷抽采措施进行作业。实践证明,该技术解决了上隅角瓦斯积聚隐患,保障了矿井高产高效。     

《陶人心语》中唐英心境浅析

唐英,清代沈阳人,隶属汉军正白旗。《陶人心语》是清代督陶官唐英撰写的诗集。该诗集内容丰富,表达了唐英对皇帝的感恩之情,以及他的赤城之心;对制陶事业的热爱之情;对亲人的思念关爱之情,体恤百姓的疾苦,关心百姓等。此书具有丰富的文学价值和历史价值。